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1

Structural and optical properties of PbSe nanostructure thin films prepared by inert gas condensation  

NASA Astrophysics Data System (ADS)

Lead Selenide (PbSe) nanostructure thin films synthesized via inert gas condensation (IGC) technique. The structure of as-prepared PbSe nanostructure thin films, were studied using Grazing incident in-plane X-ray diffraction (GIIXD). The study reveals that all films crystallized in cubic structure. The particle size (Ps) of the films, were calculated from X-ray diffraction to be ~5, 8 and 11 nm for film thicknesses 20, 46 and 87 nm respectively which have been confirmed with those determined from transmission electron microscope (TEM) micrographs. The optical energy gap was found to be increases from 2.22 eV to 2.37 eV as particle size decreases from 11 nm to 5.5 nm. In addition, the band tail width increased with decreasing the particle size but the refractive index increases with increasing the particle size of the prepared films.

Mahdy, Manal A.; Mahdy, Iman A.; Mahmoud, E. A.

2014-05-01

2

Deposition of Size-Selected Cu Nanoparticles by Inert Gas Condensation  

PubMed Central

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

2010-01-01

3

Characterization of Pb??Te?? quantum dot thin film synthesized by inert gas condensation.  

PubMed

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

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

2015-01-01

4

Purification of Inert Gas  

Microsoft Academic Search

The rate of removal of oxygen from inert gas by metallic getter is measured continuously, and the dilution model is adopted for explaining the rate of purification. The rate of removal of oxygen increases with flow rate. It is found that hydrogen and water vapor present in the inert gas contributes very effectively to reducing the oxygen partial pressure. The

Keiji NAITO; Toshihide TSUJI; Tsuneo MATSUI; Katsumi UNE

1974-01-01

5

Inert gas thrusters  

NASA Technical Reports Server (NTRS)

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

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

1979-01-01

6

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

E-print Network

­liquid interface taking into account the effect of nonisothermal gas absorption. It is demonstrated of evaporation of droplets in the flowing or stagnant gases were discussed in numerous theoretical

Elperin, Tov

7

Inert gas thrusters  

NASA Technical Reports Server (NTRS)

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.

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

1980-01-01

8

46 CFR 154.906 - Inert gas generators.  

...2014-10-01 2014-10-01 false Inert gas generators. 154.906 Section 154.906 Shipping...Cargo Containment Systems § 154.906 Inert gas generators. The inert gas generator must: (a) Produce an inert gas...

2014-10-01

9

46 CFR 154.906 - Inert gas generators.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Inert gas generators. 154.906 Section 154.906 Shipping...Cargo Containment Systems § 154.906 Inert gas generators. The inert gas generator must: (a) Produce an inert gas...

2013-10-01

10

46 CFR 154.906 - Inert gas generators.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Inert gas generators. 154.906 Section 154.906 Shipping...Cargo Containment Systems § 154.906 Inert gas generators. The inert gas generator must: (a) Produce an inert gas...

2011-10-01

11

46 CFR 154.906 - Inert gas generators.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Inert gas generators. 154.906 Section 154.906 Shipping...Cargo Containment Systems § 154.906 Inert gas generators. The inert gas generator must: (a) Produce an inert gas...

2012-10-01

12

46 CFR 154.906 - Inert gas generators.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Inert gas generators. 154.906 Section 154.906 Shipping...Cargo Containment Systems § 154.906 Inert gas generators. The inert gas generator must: (a) Produce an inert gas...

2010-10-01

13

Mechanisms of inert gas narcosis  

NASA Technical Reports Server (NTRS)

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

1973-01-01

14

46 CFR 154.904 - Inert gas system: Controls.  

Code of Federal Regulations, 2010 CFR

...and Equipment Atmospheric Control in Cargo Containment Systems...904 Inert gas system: Controls. The inert gas system must...of this section; (c) Automatic and manual inert gas pressure controls; and (d) Valves to...

2010-10-01

15

46 CFR 154.908 - Inert gas generator: Location.  

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

2014-10-01

16

46 CFR 154.908 - Inert gas generator: Location.  

Code of Federal Regulations, 2013 CFR

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

2013-10-01

17

46 CFR 154.908 - Inert gas generator: Location.  

Code of Federal Regulations, 2010 CFR

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

2010-10-01

18

46 CFR 154.908 - Inert gas generator: Location.  

Code of Federal Regulations, 2012 CFR

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

2012-10-01

19

46 CFR 154.908 - Inert gas generator: Location.  

Code of Federal Regulations, 2011 CFR

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

2011-10-01

20

Inert gas ups viscous oil production  

Microsoft Academic Search

One of the newest heavy oil-recovery techniques is that of cyclic injecting an inert gas of carbon dioxide and nitrogen in a producing well. This method has increased producing rates substantially in recent field tests. The experimental project is located in the Taylor Ina Field of Medina County in Southwest Texas. The wells previously pumped a few barrels per day,

Davison

1965-01-01

21

Barge brings inert gas where needed  

Microsoft Academic Search

The first of its class, a barge-mounted generating unit, delivers inert gas for Amerada Petroleum Corp. to Louisiana bayou wells for attic-oil recovery. The barge is made of reinforced concrete, 70 ft long and 30 ft wide. From deck to keel, it measures 12 ft. The hold of the barge is divided into floodable compartments so that the barge can

Bleakley

1968-01-01

22

46 CFR 154.903 - Inert gas systems: General.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Inert gas systems: General. 154.903 ...CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Atmospheric Control in Cargo Containment Systems § 154.903 Inert gas systems: General. (a)...

2010-10-01

23

Positron-inert gas differential elastic scattering  

NASA Technical Reports Server (NTRS)

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.

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

1990-01-01

24

Refractory metals welded or brazed with tungsten inert gas equipment  

NASA Technical Reports Server (NTRS)

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.

Wisner, J. P.

1965-01-01

25

Metal inert gas welding system for use in vacuum  

Microsoft Academic Search

Disclosed are a device and a method for inert gas plasma welding in a low pressure or vacuum environment. The device comprises: a pre-plasma cavity having a first opening therein capable of accepting an inert gas into the pre-plasma cavity, first and second electrodes within the pre-plasma cavity capable of applying an electromagnetic field to the inert gas to thereby

Charles D. Stocks

1994-01-01

26

Metal inert gas welding system for use in vacuum  

Microsoft Academic Search

Disclosed are a device and a method for inert gas plasma welding in a low pressure or vacuum environment. The device comprises: a pre-plasma cavity having a first opening therein capable of accepting an inert gas into the pre-plasma cavity, first and second electrodes within the pre-plasma cavity capable of applying an electromagnetic field to the inert gas to thereby

Charles D. Stocks

1993-01-01

27

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

Microsoft Academic Search

Experimental results of investigating steam condensation on water in the presence of (noncondensable) inert gases at low temperatures and pressures relevant to open-cycle ocean thermal energy conversion (OTEC) systems are reported. Seven different condenser configurations were tested. The experimental data are correlated using a liquid flow fraction and a vent fraction to yield simple relationships of condenser performance over a

D. Bharathan; J. Althof

1984-01-01

28

46 CFR 153.501 - Requirement for dry inert gas.  

Code of Federal Regulations, 2010 CFR

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

2010-10-01

29

46 CFR 153.500 - Inert gas systems.  

Code of Federal Regulations, 2010 CFR

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

2010-10-01

30

Inert-Gas Diffuser For Plasma Or Arc Welding  

NASA Technical Reports Server (NTRS)

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

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

1994-01-01

31

Inert states of spin-5 and spin-6 Bose-Einstein condensates  

NASA Astrophysics Data System (ADS)

In this paper, we consider spinor Bose-Einstein condensates with spin f = 5 and f = 6 in the presence and absence of an external magnetic field at the mean field level. We calculate all of the so-called inert states of these systems. Inert states are a very unique class of stationary states because they remain stationary while Hamiltonian parameters change. Their existence comes from Michel’s theorem. For illustration of symmetry properties of the inert states we use a method that allows for the classification of the systems as a polyhedron with 2f vertices proposed by Barnett et al (2006 Phys. Rev. Lett. 97 180412).

Fizia, Marcin; Sacha, Krzysztof

2012-02-01

32

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

SciTech Connect

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

Bharathan, D.; Althof, J.

1984-08-01

33

Metal inert gas welding system for use in vacuum  

NASA Astrophysics Data System (ADS)

Disclosed are a device and a method for inert gas plasma welding in a low pressure or vacuum environment. The device comprises: a pre-plasma cavity having a first opening therein capable of accepting an inert gas into the pre-plasma cavity, first and second electrodes within the pre-plasma cavity capable of applying an electromagnetic field to the inert gas to thereby convert the inert gas into a plasma and a second opening capable of allowing the plasma to exit the pre-plasma cavity and a structure capable of directing the plasma from the second opening of the pre-plasma cavity to an arc welding cavity adjacent to the second opening, the arc welding cavity capable of being placed adjacent to a working surface, the arc welding cavity further capable of accepting a welding material therein, the plasma impinging on the working surface and the welding material, the directing means focusing the plasma within the arc welding cavity to thereby increase a rate of heat transfer between the plasma and the working surface and the welding material. The present invention allows welding to be done in a vacuum by preventing the vacuum from prematurely dispersing the plasma.

Stocks, Charles D.

1994-08-01

34

Metal inert gas welding system for use in vacuum  

NASA Astrophysics Data System (ADS)

Disclosed are a device and a method for inert gas plasma welding in a low pressure or vacuum environment. The device comprises: a pre-plasma cavity having a first opening therein capable of accepting an inert gas into the pre-plasma cavity, first and second electrodes within the pre-plasma cavity capable of applying an electromagnetic field to the inert gas to thereby convert the inert gas into a plasma and a second opening capable of allowing the plasma to exit the pre-plasma cavity and a structure capable of directing the plasma from the second opening of the pre-plasma cavity to an arc welding cavity adjacent to the second opening, the arc welding cavity capable of being placed adjacent to a working surface, the arc welding cavity further capable of accepting a welding material therein, the plasma impinging on the working surface and the welding material, the directing means focusing the plasma within the arc welding cavity to thereby increase a rate of heat transfer between the plasma and the working surface and the welding material. The present invention allows welding to be done in a vacuum by preventing the vacuum from prematurely dispersing the plasma.

Stocks, Charles D.

1993-09-01

35

Repulsive Interactions and Molecular Rotation in Inert-Gas Lattices  

Microsoft Academic Search

A model is discussed from which the effect of repulsive interactions on the rotational energy levels of a solute molecule in an inert-gas lattice may be calculated. The model is based on the assumption that repulsive interactions may be understood in terms of single interatomic-exchange processes in the solid. Application is made to the case of HCl in argon, krypton,

R. L. Armstrong

1966-01-01

36

Combustion of Cr 2 O 3 + Al powder mixtures in a coflow of inert gas: 5. Effect of green density  

Microsoft Academic Search

Combustion of Cr2O3 + Al powder mixtures in a coflow of inert gas (Ar) was investigated upon variation in green density in the presence\\/absence\\u000a of blowing agents (borax, baking soda). The results were rationalized in terms of the convection-conduction theory for combustion\\u000a in heterogeneous condensed systems.

B. S. Seplyarskii; G. B. Brauer; A. G. Tarasov

2009-01-01

37

Lattice Dynamics of Inert Gas Monolayers  

NASA Astrophysics Data System (ADS)

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

Hakim, Toufic Maurice

38

Formation of porous low-dimensional nickel systems during near equilibrium condensation in ultrapure inert environment  

NASA Astrophysics Data System (ADS)

A new technique for synthesizing porous low-dimensional nickel has been developed, which involves the controlled sputter deposition of extremely small vapor fluxes in an ultrapure inert environment. This technique is based on the phase transition of sputtered substances into the condensed state under conditions close to thermodynamic equilibrium. The evolution of morphologically unique condensates which consist of weakly bound crystals have been analyzed on the basis of electron microscopy investigations. The experiments have shown that a rather prolonged condensation for durations exceeding 4 h results in the nucleation of whiskers with diameters between 30 and 600 nm. It is suggested that highly porous nickel structures obtained near thermodynamic equilibrium belong to a new zone in the structure zone model.

Perekrestov, Vyacheslav; Kornyushchenko, Anna; Kosminska, Yuliya; Wilde, Gerhard; Ostendorp, Stefan; Winkler, Nina

2014-10-01

39

46 CFR 153.462 - Static discharges from inert gas systems.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Static discharges from inert gas systems. ...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...

2013-10-01

40

46 CFR 153.462 - Static discharges from inert gas systems.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Static discharges from inert gas systems. ...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...

2012-10-01

41

46 CFR 153.462 - Static discharges from inert gas systems.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Static discharges from inert gas systems. ...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...

2011-10-01

42

Gas condensate damage in hydraulically fractured wells  

E-print Network

a 2D 1-phase simulator in order to help us to better understand the results of gas condensate simulation. Then during the research, gas condensate models with various gas compositions were simulated using a commercial simulator (CMG). The results...

Reza, Rostami Ravari

2004-11-15

43

Application of the gas phase condensation to the preparation of nanoparticles  

Microsoft Academic Search

The evaporation of materials in ultra-high vacuum leads to the growth of thin films on appropriated substrates. In the presence of an inert gas (pressure above 10?1Torr), the evaporated materials lose kinetic energy by collisions with the inert gas molecules in the gas phase and condense in the form of nanometric size crystallites that can be collected on the substrate

A. Fernández; E. P. Reddy; T. C. Rojas; J. C. Sánchez-López

1999-01-01

44

Supersonic condensation of molecular gas  

Microsoft Academic Search

The kinetic problem on supersonic condensation of polyatomic gas on a flat surface is solved by the Mott-Smith method. The\\u000a suggested model assumes a possibility of existence of a solution of the shock wave type. The contribution of the internal\\u000a degrees of freedom to the total heat capacity of gas is included. The regions of permissible values of parameters characterizing

I. A. Kuznetsova; A. A. Yushkanov; Yu. I. Yalamov

2000-01-01

45

Fog inerting effects on hydrogen combustion in a PWR ice condenser contaminant  

SciTech Connect

A mechanistic fog inerting model has been developed to account for the effects of fog on the upward lean flammability limits of a combustible mixture based on the thermal theory of flame propagation. Benchmarking of this model with test data shows reasonably good agreement between the theory and the experiment. Applications of the model and available fog data to determine the upward lean flammability limits of the H{sub 2}-air-steam mixture in the ice condenser upper plenum region of a pressurized water reactor (PWR) ice condenser contaminant during postulated large loss of coolant accident (LOCA) conditions indicate that combustion may be suppressed beyond the downward flammability limit (8 percent H{sub 2} by volume). 18 refs., 3 tabs.

Luangdilok, W. [Fauske & Associates, Inc., Burr Ridge, IL (United States); Bennett, R.B. [American Electric Power Service Corp., Columbus, OH (United States)

1995-05-01

46

46 CFR 153.462 - Static discharges from inert gas systems.  

Code of Federal Regulations, 2010 CFR

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

2010-10-01

47

Elastic electron scattering from inert-gas atoms  

SciTech Connect

We present a comprehensive set of theoretical values for differential, total, and momentum transfer cross sections for elastic scattering of electrons by inert-gas atoms, for energies below 1 keV. In addition, we also provide Sherman function values for the xenon atom at various energies. The present work includes a critical analysis of most available experimental and theoretical data, and systematic investigations on the effect of various choices for the atomic central, exchange, and polarization potential that we used in our calculations. The objective of the present work is to employ a relatively simple and semiempirical approach with a minimum number of adjustable parameters, which could generate a reliable set of cross sections for a wide range of energies. The present data are in very good agreement with prior accurate experimental and theoretical values.

Adibzadeh, Mehrdad [Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606-3390 (United States)]. E-mail: ma4j@virginia.edu; Theodosiou, Constantine E. [Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606-3390 (United States)

2005-09-01

48

Development of advanced inert-gas ion thrusters  

NASA Technical Reports Server (NTRS)

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

Poeschel, R. L.

1983-01-01

49

Relating indices of inert gas washout to localised bronchoconstriction  

PubMed Central

Asthma is typically characterised by increased ventilation heterogeneity. This can be directly inferred from the visualisation of ventilation defects in imaging studies, or indirectly inferred from indices derived from the multiple-breath nitrogen washout (MBNW). The basis for the understanding of the MBNW indices and their implication for changes in structure and function at the largest and smallest scales in the lung has been facilitated by mathematical models for inert gas transport. A new model is presented that couples airway resistance and regional tissue compliance, for simulation of the effect of ‘patchy’ bronchoconstriction - as inferred from imaging studies - on the Scond index of ventilation heterogeneity. Patches of reduced washin gas concentration can emerge by constricting only the terminal bronchioles within localised regions, however this pattern of constriction is insufficient to affect Scond; Scond from this model is only sensitive to constriction that occurs within entire contiguous regions. Furthermore the model illustrates the possibility that the MBNW may not detect gas trapped in ventilation defects.. PMID:22771781

Mitchell, Jennine H.; Hoffman, Eric A.; Tawhai, Merryn H.

2012-01-01

50

Microstructure characterization in dc sputtered aSiC:H films by inert gas effusion measurements  

Microsoft Academic Search

The effusion of argon, neon and helium as well as of hydrogen was used for microstructure characterization of dc sputtered amorphous silicon carbon (a-SiC:H) alloys deposited with various carbon and hydrogen contents. Inert gas atoms were incorporated into the material by ion implantation. Our results suggest that effusion of implanted inert gas atoms is a useful method for microstructure characterisation

R. Saleh; L. Munisa; W. Beyer

2004-01-01

51

Visual/vestibular effects of inert gas narcosis.  

PubMed

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

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

1993-08-01

52

Hepatic blood flow measurement with inert gas clearance.  

PubMed

Inert gas clearance has been used for 20 years to measure hepatic blood flow. Injection of a saline solution of 85Kr or 133Xe is usually made via the PV, and the resulting hepatic clearance is monitored with a Geiger-Müller tube, scintillation crystal, or gamma camera. Complex slow components in 133Xe clearance curves, once believed to indicate a correspondingly complex hepatic microcirculation, are now considered to be caused by nonhepatic radioactivity. Normal liver is therefore believed to receive a homogeneous perfusion throughout the depth of tissue in any given region. HA blood and PV blood are normally completely mixed in the hepatic sinusoids. Macroscopic variations in tissue perfusion may exist in different lobes of the liver in both animals and man. The technique expresses flow in units of milliliters per minute per 100 g. Accurate and acceptably reproducible results have been obtained after PV injection of isotope; fast component analysis of 133Xe clearance is most appropriate, while beta detection of 85Kr yields a simple monoexponential curve. Normal hepatic blood flow in dogs and in man is 100-130 ml min-1 100 g-1. Employing sites of isotope administration other than the PV produces inaccurate results unless appropriate corrections are made. Accuracy of flow measurement is critically dependent on a knowledge of the partition coefficient of the gas used. Liver disease per se does not affect measurement accuracy, and many practical features make the technique an attractive tool for the measurement of hepatic hemodynamics in man. Nevertheless, it is essential that the investigator be aware of certain limitations of the method, and carefully apply current concepts of clearance curve analysis and interpretation, in order to derive maximum advantage. PMID:3018367

Mathie, R T

1986-07-01

53

Solid-state ethanol fermentation by means of inert gas circulation.  

PubMed

A new method for solid-state ethanol fermentation (the SSEF system) was experimented on for the ethanol production from solid starchy materials, where a packedbed-type fermentor was used. Both cultivation of Aspergillus saitoi and enrichment of a saccharifying enzyme were effective for hydrolysis of the starch. Ethanol production was set in by a form of parallel fermentation using a respiration-deficient mutant of Saccharomyces cerevisiae. Produced ethanol was simultaneously stripped by circulating inert gas and separated in a condenser. Average ethanol concentration in the condensate was over 200 g/L, and over 90% of produced ethanol was recovered from the packed bed during 15 or 16 days of stripping. The fermentation efficiency was about 80%, which was evaluated much higher than those of conventional solid-state fermentations. The residue had lesser volume and a higher solids content compared with the distillery wastewaters of conventional liquid-state fermentations. This means an advantage for the treatment and the effective conversion of the residue into fetilizers or animal feeds. PMID:18553820

Sato, K; Nakamura, K; Sato, S

1985-09-01

54

Non-iterative condensation modeling for steam condensation with non-condensable gas in a vertical tube  

Microsoft Academic Search

Based on a heat and mass transfer analogy, an iterative condensation model for steam condensation in the presence of a non-condensable gas in a vertical tube is proposed including the high mass transfer effect, entrance effect, and interfacial waviness effect on condensation. A non-iterative condensation model is proposed for easy engineering application using the iterative condensation model and the assumption

Hee Cheon No; Hyun Sik Park

2002-01-01

55

Impact of Airway Gas Exchange on the Multiple Inert Gas Elimination Technique: Theory  

PubMed Central

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

Anderson, Joseph C.; Hlastala, Michael P.

2011-01-01

56

Influence of inert gas addition on electric breakdown using dielectric barrier discharge in oxygen  

NASA Astrophysics Data System (ADS)

This paper studies the influence of inert gas additions He, Ar, Kr and Xe on breakdown voltage within dielectric barrier discharge reactor with oxygen feed gas. The density-normalized effective ionization coefficients ?eff/N are calculated for inert gas/O2 mixtures, the critical reduced field E/Ncr is obtained where the electron ionization exactly balances the attachment. Adding inert gases would lead to the decreasing critical reduced field strength E/Ncr due to the enhancement of effective ionization coefficient. In addition, inert gas additions have shown to reduce the breakdown voltage. Moreover the numerical breakdown voltage values and the experimental data are plotted for the sake of comparison and results show that calculated results are in agreement with the experimental values. Parametric study offers substantial insight in plasma physics, as well as in ozone generation applications.

Wei, Lin-Sheng; Yuan, Ding-Kun; Zhang, Ya-Fang; Hu, Zhao-Ji; Dong, Guo-Pan

2014-07-01

57

Drain for condensate from flue gas  

Microsoft Academic Search

This patent describes the maintenance of a desired sub-atmospheric pressure in a flue gas at a selected point in a system burning hydrocarbon fuel from which water vapor condenses, a trap and drain comprising a standpipe in communication with and below a flue, means to establish an overflow level of the standpipe and to drain condensate therefrom, dip tube connected

Ahn

1986-01-01

58

Effects of inert gas dilution of silane on plasma-deposited aSi:H films  

Microsoft Academic Search

Electrical, optical, and structural characterization of hydrogenated amorphous silicon films plasma-deposited from mixtures of SiH4 with different inert-gas diluents reveals substantial differences in a number of properties. A general trend of increasing defect density with atomic weight of the inert gas is observed. Of specific interest to device applications is the observation that high deposition rates can be achieved concurrently

J. C. Knights; R. A. Lujan; M. P. Rosenblum; D. K. Bieglesen; J. A. Reimer

1981-01-01

59

Numerical Simulation on Inert Gas Injection Applied to Sealed Fire Area  

Microsoft Academic Search

\\u000a To provide a theoretical basis for application of inert gas injection measures on the mine fire disaster relief, the paper\\u000a establish mathematical model for the influence of inert gas injection to fire zone’s flow field, and the FLUENT software is\\u000a used to carry out numerical simulation, at last, the simulation results are compared with the experimental results. The result\\u000a shows

Jiuling Zhang; Xinquan Zhou; Wu Gong; Yuehong Wang

60

Effects of inert gas dilution of silane on plasma-deposited a-Si:H films  

NASA Astrophysics Data System (ADS)

Electrical, optical, and structural characterization of hydrogenated amorphous silicon films plasma-deposited from mixtures of SiH4 with different inert-gas diluents reveals substantial differences in a number of properties. A general trend of increasing defect density with atomic weight of the inert gas is observed. Of specific interest to device applications is the observation that high deposition rates can be achieved concurrently with low defect densities when helium is used as a diluent.

Knights, J. C.; Lujan, R. A.; Rosenblum, M. P.; Street, R. A.; Bieglesen, D. K.; Reimer, J. A.

1981-03-01

61

Operation of the J-series thruster using inert gas  

NASA Technical Reports Server (NTRS)

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.

Rawlin, V. K.

1982-01-01

62

Light-gas effect on steam condensation  

SciTech Connect

In a postulated reactor accident, the loss of coolant results in a release of high-temperature steam into the containment. Under these circumstances steam condensation onto containment walls provides an effective mechanism of energy removal. However, the presence of noncondensable gas is known to degrade the heat transfer. It has also been found that the introduction of a light noncondensable gas has little effect until sufficient quantities are present to disrupt the buoyancy forces. Our investigation shows the dramatic effect of high concentrations of light gas decreasing steam condensation rates under anticipated accident conditions for AP600, with helium as the simulant for hydrogen.

Anderson, M.H.; Corradini, M.L. [Univ. of Wisconsin, Madison, WI (United States); Herranz, L.E. [Centro de Investigcaiones Energeticas Medioambientales y Tecnologicas, Madrid (Spain)

1997-12-01

63

Light-gas effect on steam condensation  

Microsoft Academic Search

In a postulated reactor accident, the loss of coolant results in a release of high-temperature steam into the containment. Under these circumstances steam condensation onto containment walls provides an effective mechanism of energy removal. However, the presence of noncondensable gas is known to degrade the heat transfer. It has also been found that the introduction of a light noncondensable gas

M. H. Anderson; M. L. Corradini; L. E. Herranz

1997-01-01

64

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

SciTech Connect

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.

Chen Houlei; Zhao Miguang; Yang Luwei; Cai Jinghui; Hong Guotong; Liang Jingtao [Technical Institute of Physics and Chemistry, CAS, Beijing, 100190 (China)

2010-04-09

65

Optimization of condensing gas drive  

E-print Network

. In other words, any attempt to increase rates will decrease oil recovery at gas breakthrough. Results were determined by a laboratory investigation using displacement by a gas with essentially no solubility in the displaced liquid. The purpose.... In other words, any attempt to increase rates will decrease oil recovery at gas breakthrough. Results were determined by a laboratory investigation using displacement by a gas with essentially no solubility in the displaced liquid. The purpose...

Lofton, Larry Keith

2012-06-07

66

Recovery of Tritium in Inert Gas by Precious Metal Catalyst Supported by Hydrophilic Substrate  

Microsoft Academic Search

In this study, it is proposed to use exchange reaction between hydrogen isotopes in gas phase and those in hydrophilic substrate of the precious metal catalyst for the purpose of recovering tritium as molecular form from the inert gas such as the atomosphere in the secondary containment, where no oxygen is expected. The values of the equilibrium constant and reaction

Mikio ENOEDA; Takeshi HIGASHIJIMA; Masabumi NISHIKAWA; Nobuo MITSUISHI

1986-01-01

67

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

SciTech Connect

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.

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

1998-04-01

68

Role of Carbon Dioxide in Inert Gas Narcosis.  

National Technical Information Service (NTIS)

The role of carbon dioxide and oxygen in high pressure narcosis was studied by exposing animals to hyperbaric conditions while maintaining them normoxic and normocapnic. Chickens were the experimental animals. Heated, humidified gas entered the lung via a...

H. S. Weiss

1977-01-01

69

New inflow performance relationships for gas condensate reservoirs  

E-print Network

In this work we propose two new Vogel-type Inflow Performance Relations (or IPR) correlations for gas-condensate reservoir systems. One correlation predicts dry gas production the other predicts condensate (liquid) production. These correlations...

Del Castillo Maravi, Yanil

2004-09-30

70

Drain for condensate from flue gas  

SciTech Connect

This patent describes the maintenance of a desired sub-atmospheric pressure in a flue gas at a selected point in a system burning hydrocarbon fuel from which water vapor condenses, a trap and drain comprising a standpipe in communication with and below a flue, means to establish an overflow level of the standpipe and to drain condensate therefrom, dip tube connected to the overflow outlet means and extending downward within the standpipe to a trap level above the base of the standpipe, and downward-leading means, entering the standpipe at a level between the trap level and the overflow level, to conduct to the standpipe condensate from such selected point in the system at which such sub-atmospheric pressure is to be maintained, whereby after the standpipe is filled with water to such overflow level, such negative pressure is maintained by the rise of water from the standpipe into the downward-leading means.

Ahn, H.

1986-09-16

71

Dilution effect with inert gas in direct methanol synthesis from methane using nonthermal plasma  

Microsoft Academic Search

Direct methanol synthesis from CH4 and O2 has been experimentally studied using pulsed discharge plasma in a concentric-cylinder-type reactor. The methanol production was enhanced by dilution of source gas with inert gas, such as Ar, He. The methanol production became about 2.5 times larger at the dilution ratio of 2.5, and gradually decreased with increase of the dilution ratio, resulting

Mamoru Okumoto; Zhenzhou Su; Shinji Katsura; Akira Mizuno

1997-01-01

72

Substitution-inert trinuclear platinum complexes efficiently condense/aggregate nucleic acids and inhibit enzymatic activity.  

PubMed

The trinuclear platinum complexes (TriplatinNC-A [{Pt(NH3 )3 }2 -?-{trans-Pt(NH3 )2 (NH2 (CH2 )6 NH2 )2 }](6+) , and TriplatinNC [{trans-Pt(NH3 )2 (NH2 (CH2 )6 NH3 (+) )}2 -?-{trans-Pt(NH3 )2 (NH2 (CH2 )6 NH2 )2 }](8+) ) are biologically active agents that bind to DNA through noncovalent (hydrogen bonding, electrostatic) interactions. Herein, we show that TriplatinNC condenses DNA with a much higher potency than conventional DNA condensing agents. Both complexes induce aggregation of small transfer RNA molecules, and TriplatinNC in particular completely inhibits DNA transcription at lower concentrations than naturally occurring spermine. Topoisomerase?I-mediated relaxation of supercoiled DNA was inhibited by TriplatinNC-A and TriplatinNC at concentrations which were 60?times and 250?times lower than that of spermine. The mechanisms for the biological activity of TriplatinNC-A and TriplatinNC may be associated with their ability to condense/aggregate nucleic acids with consequent inhibitory effects on crucial enzymatic activities. PMID:25256921

Malina, Jaroslav; Farrell, Nicholas P; Brabec, Viktor

2014-11-17

73

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

NASA Technical Reports Server (NTRS)

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.

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

2007-01-01

74

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

E-print Network

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 "condensate banking...

Sandoval Rodriguez, Angelica Patricia

2012-06-07

75

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

NASA Technical Reports Server (NTRS)

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

1974-01-01

76

Changing inert gas mixing ratios on Mars using the York Mars GCM  

NASA Astrophysics Data System (ADS)

The current version of the York Mars model, GEM-MARS, is currently undergoing revision, and is being re-developed and assessed to be used in a semi-operational mode for planetary missions. GEM-Mars is based on the dynamical core of the Canadian Weather Forecast GEM (Global Environment Multi-scale) Model and our current version of GEM-MARS uses version 3.3.0. (Experiments are continuing at BIRA with a version which has a staggered vertical grid.) This study intends to focus on the condensation aspects of CO2 and its impact on the mixing ratios of inert (on a seasonal time scale) species for example such as Ar, and CO. As CO2 floods the polar atmosphere in the springtime the mixing ratios of the inert species decrease until mixing from lower latitudes adjusts the balance. In winter time the opposite sequence is obtained. We use straightforward CO2 condensation based on the work of Forget (1998) and adjust the 4D mixing ratio of the species in the column to ensure mass conservation for the basic species which make up the Martian atmosphere.

Beagley, S. R.; Fomichev, V. I.; Semeniuk, K.; Kaminski, J. W.; Wu, D.; Lupu, A.; Fazel-Rastgar, F.; McConnell, J. C.; Daerden, F.; Neary, L.

2012-12-01

77

Predictability of PaO2 in different inert gas-oxygen environments  

Microsoft Academic Search

Recent experimentation with metabolic changes in rats exposed to thermally isoconductive environments has involved the use of inert gas-oxygen mixtures with different total pressures (PT) and inspired oxygen fractions (F1O2). To determine the FIO2 for each mixture that would result in similar arterial oxygen pressures (P a O2) and saturations (OS), arterial blood of dogs breathing the mixtures through a

Christopher L. Schatte; Jack B. Simmons; David P. Clarkson; John P. Jordan

1972-01-01

78

Buffer-Gas Cooled Bose-Einstein Condensate  

E-print Network

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 ...

Ketterle, Wolfgang

79

Feasibility of waterflooding Soku E7000 gas-condensate reservoir  

E-print Network

We performed a simple 3D compositional reservoir simulation study to examine the possibility of waterflooding the Soku E7 gas-condensate reservoir. This study shows that water injection results in higher condensate recovery than natural depletion...

Ajayi, Arashi

2012-06-07

80

GAS CONDENSATION IN THE GALACTIC HALO  

SciTech Connect

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

Joung, M. Ryan; Bryan, Greg L.; Putman, Mary E., E-mail: moo@astro.columbia.edu [Department of Astronomy, Columbia University, 550 West 120th Street, New York, NY 10027 (United States)

2012-02-01

81

A Method For Estimating Pulmonary Blood Flow With Respiratory Inert Gas Analysis In An Open Gas Circuit  

Microsoft Academic Search

A model for non-invasively estimating pul- monary blood flow by applying respiratory inert gas analysis and a measuring system based on this model are described. This method allows the measurement to be performed in an open circuit gas system avoiding physiological disturbance inherent in rebreathing methods. As well, this method can be combined with a con- ventional breath-by-breath method to

K. Gan; I. Nishi; A. S. Slutsky

1990-01-01

82

Spark gap switch system with condensable dielectric gas  

DOEpatents

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.

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

1991-01-01

83

A Variable Cell Model for Simulating Gas Condensate Reservoir Performance  

E-print Network

, SPE-~~~ SPE 21428 A Variable Cell Model for Simulating Gas Condensate Reservoir Performance A Librarian, SPE, P.O. Box 833836, Richardson, TX 75083.3836 U.S.A., Telex, 730989 SPEDAL. ABSTRACT Studies of depletion performance of gas condensate reservoirs report the existence of a A variable cell model

Al-Majed, Abdulaziz Abdullah

84

The diffusion of hydrogen and inert gas in sputtered aSiC:H alloys: Microstructure study  

Microsoft Academic Search

The microstructure of DC sputtered amorphous silicon carbon (a-SiC:H) is studied by effusion measurements of hydrogen and of implanted inert gases helium, neon, argon and secondary ion mass spectrometry. The results suggest that the motion of inert gas atoms is controlled by the diffusion, greatly depending on a broadening of network openings. Already at carbon concentrations of 25at%, isolated voids

Rosari Saleh; Lusitra Munisa; Wolfhard Beyer

2006-01-01

85

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

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

86

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

E-print Network

ure Electromagnetic spectrum. a) Logarithmic scale b) Linear scale . Energy distribution for a blackbody at various temperatures Planck's distribution law for a blackbody radiator at 3000' K . ~Pa e 12 Ultraviolet spectrum Tungsten-inert gas... was made, called Heliarc welding, in which an inert- gas shield is used to protect the molten weld metal from atmos- pheric oxidants. This Heliarc process, which is called tungsten-inert gas welding (TIG), utilizes a nonconsumable elec- trode...

DeVore, Robin Kent

2012-06-07

87

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

SciTech Connect

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

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

2010-11-07

88

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

NASA Technical Reports Server (NTRS)

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.

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

1974-01-01

89

Direct-contact steam condensation with simultaneous noncondensable gas absorption  

Microsoft Academic Search

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

Vasilis Bontozoglou; Anastasios J. Karabelas

1995-01-01

90

The shear viscosity of a trapped Bose-condensed gas  

SciTech Connect

By obtaining Kubo formula type and using nonequilibrium Green's functions, we calculate the shear viscosity of a trapped Bose-condensed gas below and above the Bose-Einstein condensation temperature (T {sub BEC}). The contributions of the interactions between condensate and noncondensate atoms and between noncondensate atoms take into account to the viscous relaxation time, by evaluating second order self-energies in Beliaev approximation.

Shahzamanian, M.A. [Department of Physics, University of Isfahan, Isfahan 81744 (Iran, Islamic Republic of); Yavary, H. [Faculty of Khansar, University of Isfahan, Isfahan 81744 (Iran, Islamic Republic of)]. E-mail: hs_yavary@yahoo.com

2006-05-15

91

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

NASA Technical Reports Server (NTRS)

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.

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

1977-01-01

92

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

PubMed

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

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

2012-04-01

93

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

PubMed Central

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

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

2014-01-01

94

Determination of gas-condensate relative permeability on whole cores under reservoir conditions. [Middle East  

Microsoft Academic Search

The work reported here was undertaken on rock samples from a Middle-East carbonate retrograde condensate gas field, in order to determine relative permeability to gas and condensate curves. Special attention was given to determination of condensate minimum flowing saturation (or critical condensate saturation) and to reduction of permeability to gas in the presence of immobile condensate saturation. The originality of

J. F. Gravier; A. F. Abed; C. Barroux; P. Lemouzy

1983-01-01

95

Steam condensation inside a vertical tube with noncondensable gas  

SciTech Connect

Passive containment cooling systems are being studied extensively in order to enhance reactor simplicity. One promising concept is a system equipped with condensers submerged in pools located outside the primary containment vessel (PCV). Assuming a loss-of-coolant accident, steam flows into the condensers together with nitrogen, which fills the containment drywell. Then steam is condensed in the tubes, and the decay heat is released to the atmosphere by vaporization of the pool water, suppressing and pressure of the PCV below the design pressure. In the foregoing process, the noncondensable gas greatly lowers the heat transfer coefficient (HTC) inside the condenser tubes. Therefore the effect of noncondensable gases should be clarified to predict HTCs under such conditions. The objective of this study are to measure local HTCs inside a condenser tube and to develop their evaluation methods in the presence of noncondensable gas.

Araki, Hidefumi; Kataoka, Yoshiyuki; Murase, Michio

1994-12-31

96

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

Microsoft Academic Search

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

S. C Juang; Y. S Tarng

2002-01-01

97

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

Microsoft Academic Search

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

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

2008-01-01

98

Pulmonary blood flow measured by inspiratory inert gas concentration forcing oscillations.  

PubMed

The aim of this study was to discover if the forced inspired inert gas sinewave technique could be used to measure pulmonary blood flow, using nitrous oxide as the indicator gas, following inotropic stimulation of the heart by dobutamine, in the presence of a constant alveolar ventilation. Cardiac output (range 1-4.5 L min(-1)) was measured in six dogs by thermodilution and by calculation from the sinusoidal expired partial pressures of argon and nitrous oxide using: (i) analytical equations and a conventional continuous ventilation three-compartment lung model, which did not include recirculation; and (ii) a digital simulation tidal ventilation lung model (Gavaghan and Hahn, 1996. Respir. Physiol. 106, 209-221) which was adapted to include nitrous oxide mixed-venous recirculation from a combined single viscera compartment. The continuous ventilation model calculations always underestimated thermodilution cardiac output, with the bias error increasing to almost -1 L min(-1) at the longest forcing periods, 4-5 min. In contrast, the tidal ventilation model calculations were in close agreement to thermodilution cardiac output, with biases of -0.04 and -0.26 L min(-1) at forcing periods of 2 and 3 min, respectively. PMID:9776550

Williams, E M; Sainsbury, M C; Sutton, L; Xiong, L; Black, A M; Whiteley, J P; Gavaghan, D J; Hahn, C E

1998-07-01

99

Effects of inert gas dilution of 1,3 butadiene on plasma deposition of aC:H films  

Microsoft Academic Search

Amorphous hydrogenated carbon films (a-C:H) were deposited by the plasma decomposition of mixtures of 1,3 butadiene with different inert gas diluents (Ar, Ne, and He). Several characteristics of the plasma and the deposited films were investigated for deposition gas mixtures ranging in concentration from 0% to 90% of the diluent. Measurement of the optical emission from the plasma indicated the

Jayshree Seth; S. V. Babu

1993-01-01

100

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

SciTech Connect

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.

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

2006-06-01

101

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

PubMed

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

Wang, R R; Welsch, G E

1995-11-01

102

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

PubMed

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

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

2003-07-01

103

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

NASA Astrophysics Data System (ADS)

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

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

2005-01-01

104

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

SciTech Connect

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.

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

2001-01-01

105

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

NASA Astrophysics Data System (ADS)

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.

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

2012-03-01

106

Applications of noble gas NMR to condensed matter systems  

Microsoft Academic Search

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

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

107

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

E-print Network

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...

Carballo Salas, Jose Gilberto

2006-04-12

108

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

Microsoft Academic Search

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

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

109

In situ production of Fe–TiC surface composite coatings by tungsten-inert gas heat source  

Microsoft Academic Search

In the present study, AISI 1045 steel surfaces were alloyed with pre-placed graphite, ferrotitanium and Fe–Cr–B–Si powders by using a tungsten-inert gas (TIG) heat source. The effects of welding parameters and thickness of the pre-placed powder layers on the microstructure and properties of the coatings were also investigated. The results indicated that TiC particles can be obtained by direct metallurgical

X. H. Wang; M. Zhang; Z. D. Zou; S. L. Song; F. Han; S. Y. Qu

2006-01-01

110

Reactive Transport Modeling of Acid Gas Generation and Condensation  

SciTech Connect

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.

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

2005-01-25

111

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

SciTech Connect

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

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

2013-11-21

112

Use of inert gas jets to measure the forces required for mechanical gene transfection  

PubMed Central

Background Transferring genes and drugs into cells is central to how we now study, identify and treat diseases. Several non-viral gene therapy methods that rely on the mechanical disruption of the plasma membrane have been proposed, but the success of these methods has been limited due to a lack of understanding of the mechanical parameters that lead to cell membrane permeability. Methods We use a simple jet of inert gas to induce local transfection of plasmid DNA both in vitro (HeLa cells) and in vivo (chicken chorioallantoic membrane). Five different capillary tube inner diameters and three different gases were used to treat the cells to understand the dependency of transfection efficiency on the dynamic parameters. Results The simple setup has the advantage of allowing us to calculate the forces acting on cells during transfection. We found permeabilization efficiency was related to the dynamic pressure of the jet. The range of dynamic pressures that led to transfection in HeLa cells was small (200?±?20 Pa) above which cell stripping occurred. We determined that the temporary pores allow the passage of dextran up to 40 kDa and reclose in less than 5 seconds after treatment. The optimized parameters were also successfully tested in vivo using the chorioallantoic membrane of the chick embryo. Conclusions The results show that the number of cells transfected with the plasmid scales with the dynamic pressure of the jet. Our results show that mechanical methods have a very small window in which cells are permeabilized without injury (200 to 290 Pa). This simple apparatus helps define the forces needed for physical cell transfection methods. PMID:22963645

2012-01-01

113

Determination of Gas-Condensate Relative Permeability on Whole Cores Under Reservoir Conditions  

Microsoft Academic Search

Rock samples from a Middle East carbonate retrograde condensate gas field were studied to determine their relative permeability to gas and condensate curves. The authors emphasized the determination of condensate minimum flowing saturation-or critical condensate saturation-and the reduction of permeability to gas in the presence of immobile condensate saturation. A ternary pseudoreservoir fluid of methane\\/pentane\\/nonane made it possible to work

J. F. Gravier; P. Lemouzy; C. Barroux; A. F. Abed

1986-01-01

114

Effects of high fractional noncondensable gas on condensation in the dewvaporation desalination process  

Microsoft Academic Search

A shell and tube condenser column was designed and constructed to evaluate the performances of the steam condensation process with high fractional noncondesable gas. The process is related to steam–air mixed gas condensation in an annulus around a vertical copper tube with 10 mm outside diameter. In order to investigate the effect of condensing column length on overall heat transfer

A. M. Zhu; S. C. Wang; J. X. Sun; L. X. Xie; Z. Wang

2007-01-01

115

Direct-contact steam condensation with simultaneous noncondensable gas absorption  

SciTech Connect

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.

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

1995-02-01

116

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

SciTech Connect

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

MM Hall

2006-01-31

117

Industrial Research of Condensing Unit for Natural Gas Boiler House  

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

118

Removal of particle matter from dust-vapor-gas mixture in condenser with inclined tubes  

NASA Astrophysics Data System (ADS)

The article presents results of the research of particulate matter and droplets removal on inclined tubes of the flue gas cleaning condenser in the process of vapor condensation of vapor-and-gas emissions from kraft pulp production.

Romanova, L. V.; Gogonin, I. I.

2012-03-01

119

[Genotoxicity of stack gas condensates of Bavarian waste incineration plants. I. Stack gas condensate--sample collection techniques].  

PubMed

Investigations into the toxicity and the chemical analytics of stack gas condensates from 21 waste incineration plants (locations in Bavaria) were undertaken in the years 1990 to 1995. A decisive prerequisite was the development of a simple, standardizable technique for sample collection. It was done by condensating stack gases at 0 to 5 degrees C in an intensive glass condensator. Certain types of compounds showed a different behaviour of separation at the temperatures which were used. Whereas bivalent ionic mercury and chlorophenols were comparatively well separated with amounts of 60 to 95% and the polychlorinated dioxins, furans and biphenyls (PCBs) were sufficiently separated with 20 to 60%, less than 10% of the chlorobenzenes and polycyclic aromatics (PAHs) were found in the condensates. Sufficiently sensitive biological test procedures must be chosen for a biomonitoring of the condensates on geno- and immunotoxic effects to keep the required quantity of the condensates within practicable limits. The concentration of organic wastes was done through a solid phase extraction for the genotoxicity testing in the period from 1990 to 1991, and uniformly through a dichloromethane extraction for the biological and the simultaneous chemical analytical investigations from 1992 to 1995. PMID:10084203

Raabe, F; Brandl, A; Strobl, J; Dautzenberg, D; Lierse, C; Wichmann, G; Mücke, W

1999-02-01

120

Fuel cells for civil aircraft application: On-board production of power, water and inert gas  

Microsoft Academic Search

Fuel cell systems are regarded as a promising solution for future electrical energy generation on board of commercial aircraft. In addition to an improved efficiency such systems offer the opportunity of producing water usable for on-board purposes and provide additional functions such as inerting (providing a non-inflammable atmosphere) of the jet fuel tank. This paper presents an evaluation and assessment

Gwénaëlle Renouard-Vallet; Martin Saballus; Peter Schumann; Josef Kallo; K. Andreas Friedrich; Hans Müller-Steinhagen

121

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)

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.

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

2001-01-01

122

Development of a Market Optimized Condensing Gas Water Heater  

SciTech Connect

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

Peter Pescatore

2006-01-11

123

Inert gas jets for growth control in electron beam induced deposition  

SciTech Connect

An inert, precursor free, argon jet is used to control the growth rate of electron beam induced deposition. Adjustment of the jet kinetic energy/inlet temperature can selectively increase surface diffusion to greatly enhance the deposition rate or deplete the surface precursor due to impact-stimulated desorption to minimize the deposition or completely clean the surface. Physical mechanisms for this process are described. While the electron beam is also observed to generate plasma upon interaction with an argon jet, our results indicate that plasma does not substantially contribute to the enhanced deposition rate.

Henry, M. R.; Kim, S.; Rykaczewski, K.; Fedorov, A. G. [G. W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)

2011-06-27

124

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

USGS Publications Warehouse

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.

Verma, Mahendra K.

2012-01-01

125

Determination of gas-condensate relative permeability on whole cores under reservoir conditions  

SciTech Connect

Rock samples from a Middle East carbonate retrograde condensate gas field were studied to determine their relative permeability to gas and condensate curves. The authors emphasized the determination of condensate minimum flowing saturation-or critical condensate saturation-and the reduction of permeability to gas in the presence of immobile condensate saturation. A ternary pseudoreservoir fluid of methane/pentane/nonane made it possible to work in simulated reservoir conditions with a greater flexibility for experimental procedures. The initial water saturation equaling that in the reservoir was restored. The results of the gas-condensate indicate that the critical condensate saturations are high (the average value is 36% PV) and that the reduction of permeability to gas is higher than for a standard gas/oil system. Also presented are the details of the experimental procedures, the fluid characteristics, the results, and a discussion.

Gravier, J.F.; Lemouzy, P.; Barroux, C.; Abed, A.F.

1986-02-01

126

Bubble columns for condensation at high concentrations of noncondensable gas: Heat-transfer model and experiments  

E-print Network

Carrier gas based thermodynamic cycles are common in water desalination applications. These cycles often require condensation of water vapor out of the carrier gas stream. As the carrier gas is most likely a noncondensable ...

Narayan, G. Prakash

127

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

Microsoft Academic Search

Effect of current and gas flow rate on quality of weld in tungsten inter gas arc welding of austenitic stainless steel has been studied in the present work through experiments and analyses. Butt welded joints have been made by using several levels of current and gas flow rate. The quality of the weld has been evaluated in terms of ultimate

Pradip Kumar Pal; Goutam Nandi; Nabendu Ghosh

2011-01-01

128

Nucleation and growth of Nb nanoclusters during plasma gas condensation  

SciTech Connect

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.

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

129

Bose Einstein condensation in a gas of the Fibonacci oscillators  

E-print Network

We consider a system of the two-parameter deformed boson oscillators whose spectrum is given by a generalized Fibonacci sequence. In order to obtain the role of the deformation parameters (q1,q2) on 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 by 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.

Abdullah Algin

2008-10-10

130

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

SciTech Connect

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.

Hoshi, Y.; Yoshida, H. [National Institute of Advanced Industrial Science and Technology, Ibaraki 305-8564 (Japan)

2009-09-15

131

Design and optimization of integrated gas/condensate plants  

SciTech Connect

An optimized design is demonstrated for combining gas processing and condensate stabilization plants into a single integrated process facility. This integrated design economically provides improved condensate recovery versus use of a simple stabilizer design. A selection matrix showing likely application of this integrated process is presented for use on future designs. Several methods for developing the fluid characterization and for using a process simulator to predict future design compositions are described, which could be useful in other designs. Optimization of flowsheet equipment choices and of design operating pressures and temperatures is demonstrated including the effect of both continuous and discrete process equipment size changes. Several similar designs using a turboexpander to provide refrigeration for liquids recovery and stabilizer reflux are described. Operating overthrust and from the P/15-D platform in the Dutch sector of the North Sea has proven these integrated designs are effective. Concerns do remain around operation near or above the critical pressure that should be addressed in future work including providing conservative separator designs, providing sufficient process design safety margin to meet dew point specifications, selecting the most conservative design values of predicted gas dew point and equipment size calculated with different Equations-of-State, and possibly improving the accuracy of PVT calculations in the near critical area.

Root, C.R. [Amoco-E and P Sector, Denver, CO (United States); Wilson, J.L. [Amoco-E and C Shared Service, Houston, TX (United States)

1995-11-01

132

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

NASA Technical Reports Server (NTRS)

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

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

1976-01-01

133

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

SciTech Connect

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

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

1996-12-31

134

Experimental studies of Bose-Einstein condensation in a gas Wolfgang Ketterle, MIT  

E-print Network

of the atoms condenses in the lowest quantum state. This phenomenon was first predicted by Albert Einstein1 Experimental studies of Bose-Einstein condensation in a gas Wolfgang Ketterle, MIT with the achievement of Bose-Einstein condensation (BEC) in 1995. Because of the wealth of new phenomena which

135

Control of gas absorption in a geothermal steam direct contact condenser  

Microsoft Academic Search

The absorption of geothermal gases by the cooling water of a turbine exhaust steam condenser can be minimized by a combination of design and control technology. The condenser system should comprise the two stages of a condenser and gas cooler with parallel cooling water supply and hot water disposal systems. Each stage should operate countercurrently. The control system discussed allows

W. Hart

1980-01-01

136

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

NASA Technical Reports Server (NTRS)

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

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

2001-01-01

137

Control of gas absorption in a geothermal steam direct contact condenser  

SciTech Connect

The absorption of geothermal gases by the cooling water of a turbine exhaust steam condenser can be minimized by a combination of design and control technology. The condenser system should comprise the two stages of a condenser and gas cooler with parallel cooling water supply and hot water disposal systems. The control system discussed allows the condenser to retain its traditional flexibility of improved vacuum in cool weather and yet maintains a distribution of heat loads between the condenser and gas cooler without the use of accurate heat balances. 3 refs.

Hart, W.

1980-01-01

138

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

SciTech Connect

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

Kumar Pal, Pradip; Nandi, Goutam; Ghosh, Nabendu [Mechanical Engineering Department, Jadavpur University, Kolkata-700032 (India)

2011-01-17

139

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

SciTech Connect

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

Mielke, J.E.

1996-10-09

140

Effect of pulse current on microstructure and wear resistance of Stellite6\\/tungsten carbide claddings produced by tungsten inert gas process  

Microsoft Academic Search

In this paper, the tungsten inert gas (TIG) surfacing process was carried out in two, pulse and constant current modes to produce Stellite\\/WC composite claddings. To evaluate the coating, phase composition, microstructure, hardness and wear behavior of the clad layers were investigated. The results showed that the microstructure of the cladding was composed of a hypoeutectic structure (?+(?+WC)). The added

F. Madadi; M. Shamanian; F. Ashrafizadeh

2011-01-01

141

Combustion of bulk density powder mixtures in a coflow of inert gas: 6*(Fe 2 O 3 + 2Al) + 30% Al 2 O 3 mixtures  

Microsoft Academic Search

Investigated was the combustion of bulk density (Fe2O3 + 2Al) + 30% Al2O3 mixtures in a coflow of inert gas (Ar) in the presence\\/absence of blowing agents (borax, baking soda) and applied pressure\\u000a difference ?P. The results have been rationalized in terms of the conduction-convection theory for combustion in heterogeneous systems.

G. B. Brauer; A. G. Tarasov; B. S. Seplyarskii

2009-01-01

142

Abatement of gas-condensate hydrocarbons in a natural wetland.  

PubMed

Results of a five-year research study on natural attenuation processes in a wetland, located downgradient of a sour gas processing plant in central Alberta, Canada, show that natural attenuation may present a favourable remedial solution. Both free-phase and dissolved phase condensate have been discharging to the wetland since 1984. This condensate is primarily composed of C5 to C12 hydrocarbons, including BTEX compounds. The condensate enters the base of the wetland at 1 m below ground surface, resulting in contamination of the wetland peat and underlying clay till. The lateral extent of contamination in the wetland has remained stable, and apparent free product thickness and BTEX concentrations have decreased over time. Sorption, aerobic biodegradation, volatilization, and anaerobic biodegradation were identified as active attenuation processes at this site. Sorption and desorption processes were evaluated by laboratory testing of site soils using 14C-benzene. Linear sorption coefficients (Kd) for the surface and subsurface peat were similar (4.48-4.62 l/kg), while the Kd for the underlying silt was 0.096 l/kg. The significantly higher Kd values for the peat are attributed to the peat's higher organic content (40%), relative to the clayey silt (1%). No significant resistance to desorption was observed, however, indicating that benzene would remain mobile and bioavailable over time. Aerobic biodegradation and volatilization appear to be the main removal processes. They are enhanced by a seasonal drop in the water level from surface down to 1 m depth, resulting in an aerobic unsaturated zone. Respiration testing in the peat indicates a significant aerobic biodegradation rate of 27 mg/kg/day, equating to an estimated hydrocarbon removal rate of 5 kg/day across the 3600 m2 plume area. Surface vapour measurements indicate hydrocarbon volatilization is occurring at a rate of 3 x 10(-4) kg/m2/day, equating to a mass removal of 1 kg/day across the plume. Anaerobic biodegradation is occurring primarily in the clayey silt, based on geochemical indicator parameters, microbial analyses, and soil vapour sampling. Overall, natural attenuation appears to be a feasible remedial solution for this wetland, by providing continued removal and degradation of condensate components before they reach the downgradient surface water receptor. PMID:12046644

Moore, B J; Headley, J V; Dupont, R R; Doucette, W D; Armstrong, J E

2002-01-01

143

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

PubMed

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

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

2014-03-01

144

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...

145

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

E-print Network

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...

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

2006-01-01

146

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

E-print Network

THE EFFECTS OF NON-CONDENSIBLE GAS AND SALINITY ON STEAM ADSORPTION A REPORT SUBMITTED . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2.3.1 Using Steam . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 2.3.2 Using Non-Condensible reservoir materials was investigated by a transient flow technique using steam and C02 gas. Theoretical

Stanford University

147

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

Microsoft Academic Search

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

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

1983-01-01

148

An approach to the aerothermodynamic performance prediction of gas turbines containing wet steam condensation  

Microsoft Academic Search

After introducing the basic relation and fundamental equations of gas turbines containing wet steam condensation, a simple method is suggested which replaces the condensation and heat release process thermodynamically by an equivalent polytropic process such that the usual gas medium calculation program could be employed and performance prediction could be easily made. Calculated performance of this type of turbo expander

Z. Ling; S. Li; Y. Fei

1986-01-01

149

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

Microsoft Academic Search

The Henry's law constant (KH) of perfluorooctanoic acid (PFOA, C7F15C(O)OH) was determined at 298K in aqueous sulfuric acid solutions and in aqueous sodium chloride and sulfuric acid mixtures by an inert-gas stripping method in which a helical plate was used to increase the residence time of the gas bubbles in the solutions. The partial pressures of C7F15C(O)OH in the purge

Shuzo Kutsuna; Hisao Hori

2008-01-01

150

Comparison of water-based foam and inert-gas mass emergency depopulation methods.  

PubMed

Current control strategies for avian influenza (AI) and other highly contagious poultry diseases include surveillance, quarantine, depopulation, disposal, and decontamination. Selection of the best method of emergency mass depopulation involves maximizing human health and safety while minimizing disease spread and animal welfare concerns. Proper selection must ensure that the method is compatible with the species, age, housing type, and disposal options. No one single method is appropriate for all situations. Gassing is one of the accepted methods for euthanatizing poultry. Whole-house, partial-house, or containerized gassing procedures are currently used. The use of water-based foam was developed for emergency mass depopulation and was conditionally approved by the United States Department of Agriculture in 2006. Research has been done comparing these different methods; parameters such as time to brain death, consistency of time to brain death, and pretreatment and posttreatment corticosterone stress levels were considered. In Europe, the use of foam with carbon dioxide is preferred over conventional water-based foam. A recent experiment comparing CO2 gas, foam with CO2 gas, and foam without CO2 gas depopulation methods was conducted with the use of electroencephalometry results. Foam was as consistent as CO2 gassing and more consistent than argon-CO2 gassing. There were no statistically significant differences between foam methods. PMID:20521728

Alphin, R L; Rankin, M K; Johnson, K J; Benson, E R

2010-03-01

151

A CLOSER LOOK AT CONDENSATE INJECTION INTO LANDFILL GAS FLARES  

Microsoft Academic Search

With the benefits of condensate injection becoming more and more apparent, disposing liquids into an enclosed flare system is becoming increasingly popular. While not adversely effecting flare emissions, condensate injection offers a simple, less expensive way of disposing condensate than the alternatives of hauling and\\/or treating the liquid. Not only can the alternatives cost nearly $1.00 per gallon to haul,

Brandy Smith Johnson

152

Experimental and empirical study of steam condensation heat transfer with a noncondensable gas in a small-diameter vertical tube  

Microsoft Academic Search

An experimental study was performed to investigate local condensation heat transfer coefficients in the presence of a noncondensable gas inside a vertical tube. The data obtained from pure steam and steam\\/nitrogen mixture condensation experiments were compared to study the effects of noncondensable nitrogen gas on the annular film condensation phenomena. The condenser tube had a relatively small inner diameter of

Kwon-Yeong Lee; Moo Hwan Kim

2008-01-01

153

Lifetimes of Excited Alkalilike Atoms Colliding by Van der Waals Forces with Inert Gas Atoms in the Groundstate  

NASA Astrophysics Data System (ADS)

The influence of Van der Waals forces on the lifetime of coherently excited hyperfine-states |FimFi and |FimFi of alkalilike atoms i by collissions with inert gas atoms j in the groundstate |FjmFi has been examined. To do this the timedependent Schrödinger equation has been solved on taking into account a static magnetic field, a radiation field and a Van der Waals force. Introducing an impact parameter model for the colliding atoms with small scattering angles which form a quasimolecule |? = |FimFiFjmFi an expression for the cross section ?? has been derived which determines the halfwidth ?? of the coherently excited states. On making use of the irreducible tensor representation the calculation of the cross-section has been reduced to the calculation of multipole transitions. The result has been applied e. g. to the coherently excited 3d104p2P3/2-states of Cu I colliding by dipole-dipole interaction with inert gas atoms He I, and Ar I in the ground state. The values agree well with data which have been derived from zero-level-crossing experiments.Translated AbstractLebensdauern angeregter alkaliähnlicher Atome bei Wechselwirkung über van der Waalssche Kräfte mit Inertgasatomen im GrundzustandDer Einfluß der Van-der-Waals-Wechselwirkung auf die Lebensduer kohärent angeregter Hyperfeinzustände |FimFi und |FimFi alkaliähnlicher Atome i bei Stößen mit Edelgasatomen j im Grundzustand |FimFi wurde untersucht. Hierzu wurde die zeitabhängige Schrödinger-Gleichung unter Berücksichtigung eines statischen Magnetfeldes, eines Strahlungsfeldes und Van der Waals Kräften gelöst. Durch Einführung eines Stoßparametermodells für kleine Streuwinkel der miteinander wechselwirkenden Atome, die als Quasimolekül |? = |FimFiFimFi angenommen wurden, wurde eine Beziehung für den Wirkungsquerschnitt ?? abgeleitet, der die Halbwertsbreite ?? der kohärent angeregten Zustände bestimmt. Durch Verwendung der irreduziblen Tensordarstellung wurde die Berechnung der Wirkungsquerschnitte auf die Bestimmung von Multipolübergängen reduziert. Das Ergebnis wurde beispielhaft auf die kohärent angeregten 3d104p2P3/2-Zustände von Cu I für den Fall der Dipol-Dipol-Wechselwirkung mit He I, Ne I und Ar I im Grundzustand angewendet. Die Übereinstimmung mit Nullfeldcrossing-Experimenten ist gut.

Siefart, E.

154

Compositions of the condensed medium and gas phase forming upon heating of uranium oxides (UO 2 , UO 3 , U 3 O 8 , and U 4 O 9 ) in argon and oxygen atmosphere: Computer experiment  

Microsoft Academic Search

Thermodynamic modeling methods have been used for calculating the compositions of the condensed medium and gas phase forming\\u000a upon heating of the oxides UO2, UO3, U3O8, and U4O9 at constant pressure (p = 0.1 MPa) in the temperature range 300–2000 K in an inert (Ar) or oxidative (O2) atmosphere. The stability of uranium oxides and the state of aggregation of

G. K. Moiseev; A. B. Shubin; T. V. Kulikova; A. L. Ivanovskii

2008-01-01

155

Hot nanoindentation in inert environments  

E-print Network

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 ...

Trenkle, Jonathan C.

156

Fermion-fermion interaction in a dilute gas-mixture Bose condensate  

SciTech Connect

A mixture of a one-component Bose gas and two-component Fermi gas is considered at temperatures at which the Bose gas is completely condensed. Two fermions in such a mixture can interact with each other exchanging bosons from the condensate or supercondensate. The interaction potential, a change in the effective mass, the decay, and fermion spectrum are calculated in this quantum Fermi-Bose mixture.

Mogilyuk, T. I., E-mail: 5taras@mail.ru [National Research Centre Kurchatov Institute (Russian Federation)

2011-11-15

157

Altering Wettability in Gas Condensate Sandstone Reservoirs for Gas Mobillity Improvement  

E-print Network

. ______________ This thesis follows the style of SPE Journal. ? Fig Fig blo (Ka mo how ban foc F . 1-Gas-conde . 2 shows th cks the nea math 2007) re in extrem the satura king affect us of our stu ig. 2-Conden nsate phase d sta e condensat r... is 541 Mscf/D of gas and 198 bbl/D of condensate. Production decline is observed in Fig. 3 below. There was an estimate that only 10% of the OGIP could be recovered, even with the reservoir pressure still above the dewpoint pressure. Fracturing...

Fernandez Martinez, Ruth Gabriela

2012-07-16

158

Transition from natural to mixed convection for steam–gas flow condensing along a vertical plate  

Microsoft Academic Search

An analysis method based on two-phase boundary layer analysis has been developed to study the effects of superimposed forced convection on natural convection steam–gas flow condensing along a vertical plate. The mechanism by which superimposed forced convection enhances heat transfer is evaluated: the bulk flow blows away non-condensable gases accumulating near the interface, resulting in an elevated condensation driving force.

Y. Liao; K. Vierow; A. Dehbi; S. Guentay

2009-01-01

159

Determination of gas-condensate relative permeability on whole cores under reservoir conditions. [Middle East  

SciTech Connect

The work reported here was undertaken on rock samples from a Middle-East carbonate retrograde condensate gas field, in order to determine relative permeability to gas and condensate curves. Special attention was given to determination of condensate minimum flowing saturation (or critical condensate saturation) and to reduction of permeability to gas in the presence of immobile condensate saturation. The originality of this work lies in the use of a pseudoreservoir fluid, made up of a methane-pentane-nonane ternary mixture. This choice made it possible to work in conditions representative of reservoir conditions, but with a greater flexibility for experimental procedures. The initial water saturation was restored as in the reservoir. Results indicate two specific behaviours of the gas-condensate system: critical condensate saturations are high (the average value is 36% P.V.), and reduction of permeability to gas is higher than for a standard gas-oil system. Details on experimental procedures, fluid characteristics, results and discussion of these results are reported in this paper.

Gravier, J.F.; Abed, A.F.; Barroux, C.; Lemouzy, P.

1983-03-01

160

Study of the fusion zone and heat-affected zone microstructures in tungsten inert gas-welded INCONEL 738LC superalloy  

Microsoft Academic Search

The fusion zone and heat-affected zone (HAZ) microstructures obtained during tungsten inert gas (TIG) welding of a commercial\\u000a superalloy IN 738LC were examined. The microsegregation observed during solidification in the fusion zone indicated that while\\u000a Co, Cr, and W segregated to the ? dendrites, Nb, Ti, Ta, Mo, Al, and Zr were rejected into the interdendritic liquid. Electron\\u000a diffraction and

O. A. Ojo; N. L. Richards; M. C. Chaturvedi

2006-01-01

161

Quantum control of I2 in the gas phase and in condensed phase solid Kr matrix  

E-print Network

into account using both exact quantum dynamics and nearly classical theory. For the condensed phase, since control is indeed possible in con- densed phases. There are two paradigms for quantum control: a dynamicQuantum control of I2 in the gas phase and in condensed phase solid Kr matrix Christopher J

Apkarian, V. Ara

162

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

SciTech Connect

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.

TERRI, FELLINGER

2004-12-21

163

Non-Condensable Gas Absorption by Capillary Waves  

NASA Astrophysics Data System (ADS)

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

Andre, Matthieu A.; Bardet, Philippe M.

2013-03-01

164

Condensate fraction of a two-dimensional attractive Fermi gas  

SciTech Connect

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

Salasnich, Luca [CNR-INFM and CNISM, Dipartimento di Fisica 'Galileo Galilei', Universita di Padova, Via Marzolo 8, 35131 Padova (Italy)

2007-07-15

165

An approach to the aerothermodynamic performance prediction of gas turbines containing wet steam condensation  

NASA Astrophysics Data System (ADS)

After introducing the basic relation and fundamental equations of gas turbines containing wet steam condensation, a simple method is suggested which replaces the condensation and heat release process thermodynamically by an equivalent polytropic process such that the usual gas medium calculation program could be employed and performance prediction could be easily made. Calculated performance of this type of turbo expander shows good agreement with test results.

Ling, Z.; Li, S.; Fei, Y.

1986-05-01

166

Bose-Einstein condensation in an ultra-hot gas of pumped magnons  

NASA Astrophysics Data System (ADS)

Bose-Einstein condensation of quasi-particles such as excitons, polaritons, magnons and photons is a fascinating quantum mechanical phenomenon. Unlike the Bose-Einstein condensation of real particles (like atoms), these processes do not require low temperatures, since the high densities of low-energy quasi-particles needed for the condensate to form can be produced via external pumping. Here we demonstrate that such a pumping can create remarkably high effective temperatures in a narrow spectral region of the lowest energy states in a magnon gas, resulting in strikingly unexpected transitional dynamics of Bose-Einstein magnon condensate: the density of the condensate increases immediately after the external magnon flow is switched off and initially decreases if it is switched on again. This behaviour finds explanation in a nonlinear ‘evaporative supercooling’ mechanism that couples the low-energy magnons overheated by pumping with all the other thermal magnons, removing the excess heat, and allowing Bose-Einstein condensate formation.

Serga, Alexander A.; Tiberkevich, Vasil S.; Sandweg, Christian W.; Vasyuchka, Vitaliy I.; Bozhko, Dmytro A.; Chumak, Andrii V.; Neumann, Timo; Obry, Björn; Melkov, Gennadii A.; Slavin, Andrei N.; Hillebrands, Burkard

2014-03-01

167

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

SciTech Connect

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

Borg, I.Y.

1982-08-23

168

Effect of an interfacial shear stress on steam condensation in the presence of a noncondensable gas in a vertical tube  

Microsoft Academic Search

Experimental and analytical studies were performed to examine local condensation heat transfer coefficients in the presence of a noncondensable gas inside a vertical tube. The experimental data for pure steam and steam\\/nitrogen mixture bypass modes were compared to study the effects of noncondensable nitrogen gas on annular film condensation phenomena. The condenser tube had a relatively small inner diameter of

Kwon-Yeong Lee; Moo Hwan Kim

2008-01-01

169

Pair condensation in a dilute Bose gas with Rashba spin-orbit coupling  

NASA Astrophysics Data System (ADS)

We show that in a two-component Bose gas with Rashba spin-orbit coupling (SOC), two atoms can form bound states (Rashbons) with any intra-species scattering length. At zero center-of-mass momentum, there are two degenerate Rashbons due to time-reversal symmetry, but the degeneracy is lifted at finite in-plane momentum with two different effective masses. A stable Rashbon condensation can be created in a dilute Bose gas with attractive intra-species and repulsive inter-species interactions. The critical temperature of Rashbon condensation is about six times smaller than the Bose-Einstein condensation transition temperature of an ideal Bose gas. Due to the Rashba SOC, excitations in the Rashbon condensation phase are anisotropic in momentum space.

Li, Rong; Yin, Lan

2014-05-01

170

Economic analysis of condensers for water recovery in steam injected gas turbines  

SciTech Connect

Steam injection cycles are interesting for small power ranges because of the high efficiency and the relatively low investment costs. A big disadvantage is the consumption of water by the cycle. Water recovery is seldom realized in industrial practice. In this paper an analysis of the technical and economical possibilities of water recovery by condensation of water out of the exhaust gases is made. Three gas turbines are considered : the Kawasaki M1A-13CC (2.3 MWe), the Allison 501KH (6.8 MWe) and the General Electric LM1600 (17 MWe). For every gas turbine two types of condensers are designed. In the water cooled condenser finned tubes are used to cool the exhaust gases, flowing at the outside of the tubes. The water itself flows at the inside of the tubes and is cooled by a water to air cooler. In the air cooled condenser the exhaust gases flow at the inside of the tubes and the cooling air at the outside. The investment costs of the condensers is compared to the costs of the total installation. The investment costs are relatively smaller if the produced power goes up. The water cooled condenser with water to air cooler is cheaper than the air cooled condenser. Using a condenser results in higher exploitation costs due to the fans and pumps. It is shown that the air cooled condenser has lower exploitation costs than the water cooled one. Pay back time of the total installation does not significantly vary compared to the installation without recovery. Water prices are determined for which water recovery is profitable. For the water cooled condenser the turning point lies at 2.2 Euro/m; for the air cooled condenser this is 0.6 Euro/m.

De Paepe, M.; Huvenne, P.; Dick, E.

1998-07-01

171

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

SciTech Connect

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

Elmore, M.R.

1996-02-01

172

Some effects of non-condensible gas in geothermal reservoirs with steam-water counterflow  

SciTech Connect

A mathematical model is developed for fluid and heat flow in two-phase geothermal reservoirs containing non-condensible gas (CO{sub 2}). Vertical profiles of temperature, pressures and phase saturations in steady-state conditions are obtained by numerically integrating the coupled ordinary differential equations describing conservation of water, CO{sub 2}, and energy. Solutions including binary diffusion effects in the gas phase are generated for cases with net mass throughflow as well as for balanced liquid-vapor counterflow. Calculated examples illustrate some fundamental characteristics of two-phase heat transmission systems with non-condensible gas. 14 refs., 3 figs.

McKibbin, R.; Pruess, K.

1988-01-01

173

Four-quark condensates and chiral symmetry restoration in a resonance gas model  

E-print Network

As an alternative to the two-quark condensate we propose a specific four-quark condensate as an order parameter of chiral symmetry restoration. We show that this four-quark condensate is closer connected to observable quantities. Within a resonance gas model we calculate the in-medium changes of two- and four-quark condensate as functions of temperature and baryo-chemical potential. In this way we estimate the line of chiral symmetry restoration in the temperature-potential plane and also as a function of energy and baryon density. It turns out that the line determined from the vanishing of the four-quark condensate is extremely constant as a function of the energy density.

Stefan Leupold

2006-04-06

174

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

NASA Astrophysics Data System (ADS)

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

Gensterblum, Y.; Krooss, B. M.

2013-12-01

175

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)

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).

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

1999-01-01

176

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

E-print Network

to the natural gas company, which can either store the gas as liquefied natural gas, or deliver the final product to the consumer. In 2008, 23 Tcf of natural gas was consumed in the United States in the following manner (Energy Information... development. 1.4.1. The Arun Field The Arun Field is located on the northern coast of Aceh Province in North Sumatra, Indonesia. The Arun reservoir had an initial gas in place of 16.8 TCF of dry gas and an initial condensate in place...

Miller, Nathan

2010-07-14

177

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

SciTech Connect

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

Lekov, Alex; Franco, Victor; Meyers, Steve

2010-05-14

178

Effect of noncondensable gas on Steam Condensation in Passive containment cooling tube  

Microsoft Academic Search

A theoretical model has been developed to study the local heat transfer coefficient of a condensing vapour in the presence of a noncondensable gas, where the gas\\/vapor mixture is flowing downward inside a vertical tube. The two-phase heat transfer is analysed assuming an annular flow pattern with a liquid film at the tube wall and a turbulent gas\\/vapour core. The

N. K. Maheshwari; P. K. Vijayan; D. Saha

179

Hydrate formation and inhibition in gas condensate and hydrocarbon liquid systems  

SciTech Connect

Hydrate forming conditions have been determined for gas condensate and several separator hydrocarbon liquids in the presence of methanol or ethylene glycol solutions. Measurements were in HL1L2G region for the gas condensate stream, and in HL1L2 and HL1L2G regions for the separator liquids. Inhibitor concentrations up to 29 wt % methanol and 39% mono-ethylene glycol were used. Temperatures ranged from about 0/sup 0/ to 25/sup 0/C and pressures were up to 20 MPa.

Ng, H.J.; Chen, C.J.; Saeterstad, T.

1987-01-01

180

Evaporation and condensation in a polyatomic Knudsen gas  

Microsoft Academic Search

Based upon the scattering law and reciprocity, the evaporation coefficient and accommondation coefficients characterizing the interface heat and mass transfer of a polyatomic gas are defined. The particle flux and the heat flux through a polyatomic Knudsen gas between parallel surfaces are found to be the solutions of two Fredholm integral equations. A Neumann series leads to Onsager's reciprocity relations

H. Lang

1981-01-01

181

FORMATION OF POLYCYCLIC AROMATIC HYDROCARBONS AND CARBONACEOUS SOLIDS IN GAS-PHASE CONDENSATION EXPERIMENTS  

SciTech Connect

Carbonaceous grains represent a major component of cosmic dust. In order to understand their formation pathways, they have been prepared in the laboratory by gas-phase condensation reactions such as laser pyrolysis and laser ablation. Our studies demonstrate that the temperature in the condensation zone determines the formation pathway of carbonaceous particles. At temperatures lower than 1700 K, the condensation by-products are mainly polycyclic aromatic hydrocarbons (PAHs) that are also the precursors or building blocks for the condensing soot grains. The low-temperature condensates contain PAH mixtures that are mainly composed of volatile three to five ring systems. At condensation temperatures higher than 3500 K, fullerene-like carbon grains and fullerene compounds are formed. Fullerene fragments or complete fullerenes equip the nucleating particles. Fullerenes can be identified as soluble components. Consequently, condensation products in cool and hot astrophysical environments such as cool and hot asymptotic giant branch stars or Wolf-Rayet stars should be different and should have distinct spectral properties.

Jaeger, C.; Huisken, F.; Henning, Th. [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Mutschke, H.; Jansa, I. Llamas [Astrophysikalisches Institut und Universitaets-Sternwarte (AIU), Friedrich-Schiller-Universitaet Jena, Schillergaesschen 2-3, D-07745 Jena (Germany)], E-mail: Cornelia.Jaeger@uni-jena.de

2009-05-01

182

Condensation and quasicondensation in an elongated three-dimensional Bose gas  

NASA Astrophysics Data System (ADS)

We study the equilibrium correlations of a Bose gas in an elongated three-dimensional harmonic trap using a grand-canonical classical-field method. We focus in particular on the progressive transformation of the gas from the normal phase, through a phase-fluctuating quasicondensate regime to the so-called true-condensate regime, with decreasing temperature. Choosing realistic experimental parameters, we quantify the density fluctuations and phase coherence of the atomic field as functions of the system temperature. We identify the onset of Bose condensation through analysis of both the generalized Binder cumulant appropriate to the inhomogeneous system, and the suppression of the effective many-body T matrix that characterizes interactions between condensate atoms in the finite-temperature field. We find that the system undergoes a second-order transition to condensation near the critical temperature for an ideal Bose gas in the strongly anisotropic three-dimensional geometry but remains in a strongly phase-fluctuating quasicondensate regime until significantly lower temperatures. We characterize the crossover from a quasicondensate to a true condensate by a qualitative change in the form of the nonlocal first-order coherence function of the field and compare our results to those of previous works employing a density-phase Bogoliubov-de Gennes analysis.

Garrett, Michael C.; Wright, Tod M.; Davis, Matthew J.

2013-06-01

183

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

E-print Network

was used or neglected during a depletion process. To accomplish this, we analyzed several z-grid sizes and well completion cases, for volatile oil, gas condensate and two-phase reservoirs. The studied reservoir fluid belongs to the Cusiana gas condensate...

Jaramillo Arias, Juan Manuel

2012-06-07

184

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

E-print Network

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...

Zapata Arango, Jose? Francisco

2012-06-07

185

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

E-print Network

that the proposed concept (i.e., a radially-varying gas permeability) is oversimplified, in particular, it ignores the diffusive effects of the condensate (i.e., the viscosity-compressibility behavior). However, we have effectively validated the proposed model...

Wilson, Benton Wade

2004-09-30

186

Vortices in an Imperfect Bose Gas. I. The Condensate  

Microsoft Academic Search

A theoretical study of rectilinear vortices in an imperfect Bose gas shows a close correspondence with classical hydrodynamics. The energy and momentum of a vortex pair in an unbounded fluid are calculated. The similarity between a vortex pair and a vortex ring leads to an estimate of the critical velocity vc of liquid He II in a tube of radius

Alexander L. Fetter

1965-01-01

187

Bose-Einstein condensation in an ultra-hot gas of pumped magnons.  

PubMed

Bose-Einstein condensation of quasi-particles such as excitons, polaritons, magnons and photons is a fascinating quantum mechanical phenomenon. Unlike the Bose-Einstein condensation of real particles (like atoms), these processes do not require low temperatures, since the high densities of low-energy quasi-particles needed for the condensate to form can be produced via external pumping. Here we demonstrate that such a pumping can create remarkably high effective temperatures in a narrow spectral region of the lowest energy states in a magnon gas, resulting in strikingly unexpected transitional dynamics of Bose-Einstein magnon condensate: the density of the condensate increases immediately after the external magnon flow is switched off and initially decreases if it is switched on again. This behaviour finds explanation in a nonlinear 'evaporative supercooling' mechanism that couples the low-energy magnons overheated by pumping with all the other thermal magnons, removing the excess heat, and allowing Bose-Einstein condensate formation. PMID:24613901

Serga, Alexander A; Tiberkevich, Vasil S; Sandweg, Christian W; Vasyuchka, Vitaliy I; Bozhko, Dmytro A; Chumak, Andrii V; Neumann, Timo; Obry, Björn; Melkov, Gennadii A; Slavin, Andrei N; Hillebrands, Burkard

2014-01-01

188

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

PubMed

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

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

2008-08-01

189

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

SciTech Connect

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

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

2010-11-07

190

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

PubMed

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

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

2013-01-01

191

Condensation and vortex formation in a Bose gas upon cooling  

SciTech Connect

The mechanism for the transition of a Bose gas to the superfluid state via thermal fluctuations is considered. It is shown that in the process of external cooling some critical fluctuations (instantons) are formed above the critical temperature. The probability of the instanton formation is calculated in the three- and two-dimensional cases. It is found that this probability increases as the system approaches the transition temperature. It is shown that the evolution of an individual instanton is impossible without the formation of vortices in its superfluid part.

Brener, E. A. [Institut fuer Festkoerperforschung, Forschungszentrum Juelich, 52425 Juelich (Germany); Iordanskiy, S. V.; Saptsov, R. B. [Landau Institute for Theoretical Physics, RAS, 119334 Kosygin str.2, Moscow (Russian Federation)

2006-01-15

192

Condensation and vortex formation in a Bose gas upon cooling.  

PubMed

The mechanism for the transition of a Bose gas to the superfluid state via thermal fluctuations is considered. It is shown that in the process of external cooling some critical fluctuations (instantons) are formed above the critical temperature. The probability of the instanton formation is calculated in the three- and two-dimensional cases. It is found that this probability increases as the system approaches the transition temperature. It is shown that the evolution of an individual instanton is impossible without the formation of vortices in its superfluid part. PMID:16486236

Brener, E A; Iordanskiy, S V; Saptsov, R B

2006-01-01

193

Effect of disorder on condensation in the lattice gas model on a random graph  

NASA Astrophysics Data System (ADS)

The lattice gas model of condensation in a heterogeneous pore system, represented by a random graph of cells, is studied using an exact analytical solution. A binary mixture of pore cells with different coordination numbers is shown to exhibit two phase transitions as a function of chemical potential in a certain temperature range. Heterogeneity in interaction strengths is demonstrated to reduce the critical temperature and, for large-enough degreeS of disorder, divides the cells into ones which are either on average occupied or unoccupied. Despite treating the pore space loops in a simplified manner, the random-graph model provides a good description of condensation in porous structures containing loops. This is illustrated by considering capillary condensation in a structural model of mesoporous silica SBA-15.

Handford, Thomas P.; Dear, Alexander; Pérez-Reche, Francisco J.; Taraskin, Sergei N.

2014-07-01

194

Effect of disorder on condensation in the lattice gas model on a random graph.  

PubMed

The lattice gas model of condensation in a heterogeneous pore system, represented by a random graph of cells, is studied using an exact analytical solution. A binary mixture of pore cells with different coordination numbers is shown to exhibit two phase transitions as a function of chemical potential in a certain temperature range. Heterogeneity in interaction strengths is demonstrated to reduce the critical temperature and, for large-enough degreeS of disorder, divides the cells into ones which are either on average occupied or unoccupied. Despite treating the pore space loops in a simplified manner, the random-graph model provides a good description of condensation in porous structures containing loops. This is illustrated by considering capillary condensation in a structural model of mesoporous silica SBA-15. PMID:25122288

Handford, Thomas P; Dear, Alexander; Pérez-Reche, Francisco J; Taraskin, Sergei N

2014-07-01

195

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

NASA Astrophysics Data System (ADS)

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

Kutsuna, Shuzo; Hori, Hisao

196

Terahertz active photonic crystals for condensed gas sensing.  

PubMed

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

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

2011-01-01

197

Terahertz Active Photonic Crystals for Condensed Gas Sensing  

PubMed Central

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

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

2011-01-01

198

Measurement of total fraction condensed and phase boundary for a simulated natural gas. Research report  

SciTech Connect

The experimental investigation summarized in RR-56 completes a multiyear effort under Project 737 to obtain vapor-liquid equilibria of assessed accuracy on simulated natural gas systems representative of cryogenic gas processing. The current system consisting of four components, nitrogen, methane, ethane, and propane, was studied in the pressure-temperature region commensurate with turboexpander outlet conditions. The primary intent of Project 737 is to initiate a data base of evaluated experimental accuracy from which various existing vapor-liquid equilibria models can be evaluated rigorously and subsequently improved. For this purpose component equilibrium ratios or K-values are necessary. Equally important, however, is a comparison of the effect of deviations in predicted K-values on the amount of liquid condensation at a specified condition. Measurements of the amount of liquid condensed provided in the foregoing investigations permit this additional evaluation.

Oscarson, J.L.; Saxey, B.

1982-05-01

199

Enhanced Natural Gas and Condensate Recovery by Carbon Dioxide and Methane Flooding  

Microsoft Academic Search

The authors quantitatively investigates the recovery efficiency, pattern behavior, and relative permeability of (a) condensate following supercritical carbon dioxide (CO2) injection, methane (CH4) injection, and the injection of their mixtures; and (b) natural gas of various compositions following pure supercritical CO2 injection. A high-pressure high-temperature experimental laboratory was established to simulate reservoir conditions and to perform relative permeability measurements on

A. Al-Abri; H. Sidiq; R. Amin

2012-01-01

200

Inert electrode connection  

DOEpatents

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

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

1985-01-01

201

Inert electrode connection  

DOEpatents

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.

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

1985-02-19

202

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

SciTech Connect

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. These particulates are thought to be responsible for plugging the downstream High Efficiency Mist Eliminator filters. Therefore, the OGCT needs to be periodically cleaned to remove the build-up of entrained solids. Currently, the OGCT is cleaned by adding nominally 12 wt% nitric acid with agitation to slurry the solids from the tank. Samples from the OGCT were sent to the Savannah River National Lab (SRNL) for characterization and to conduct tests to determine the optimum nitric acid concentration and residence time to allow more effective cleaning of the OGCT. This report summarizes the chemical and radionuclide results and the results from the nitric acid dissolution testing at 50% and 12% obtained for the OGCT sample.

Fellinger, T

2005-04-08

203

Intraspecific variation in tracheal volume in the American locust, Schistocerca americana, measured by a new inert gas method.  

PubMed

The volume of a tracheal system influences breath-holding capacity and provides an index of an insect's investment in its respiratory system. Here, we describe a new, generally applicable method to measure tracheal volume that enables repeatable determinations on live animals. Animals are isolated in a closed chamber of a known volume and equilibrated with a helium:oxygen gas mixture. The chamber is then rapidly flushed with a nitrogen:oxygen gas mixture to eliminate the helium surrounding the animal, and sealed. After a period of time sufficient to allow equilibration of helium between tracheal system and chamber air, a gas sample is taken from the chamber, and tracheal volumes are calculated from the helium content of the sample, using a gas chromatograph. We show that relative investment in the tracheal system increases with age/size in the grasshopper; tracheal volume scales with mass to the power 1.3. This increased proportional investment in the tracheal system provides a mechanistic basis for the enhanced respiratory capacity of older grasshoppers. Tracheal volumes decrease strongly as grasshoppers grow within an instar stage, explaining reduced safety margins for oxygen delivery. Finally, tracheal volumes are smaller in gravid females than males, probably due to compression of air sacs by eggs. PMID:16916983

Lease, Hilary M; Wolf, Blair O; Harrison, Jon F

2006-09-01

204

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

SciTech Connect

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

Dell'Anna, L.; Mazzarella, G.; Salasnich, L. [Dipartimento di Fisica ''Galileo Galilei'' and CNISM, Universita di Padova, I-35122 Padova (Italy)

2011-09-15

205

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

SciTech Connect

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

Tiejun Wu; Karen Vierow [400 Central Drive, School of Nuclear Engineering, Purdue University, West Lafayette, IN 47907-2017 (United States); Hideaki Tokuma [Nuclear Power Engineering Dept., Mechanical Design Group, Tokyo Electric Power Company, 1-3 Uchisaiwai-cho, 1-chomeChiyoda-ku, Tokyo 100-0011 (Japan)

2004-07-01

206

Visualization of inert gas wash-out during high-frequency oscillatory ventilation using fluorine-19 MRI.  

PubMed

High-frequency oscillatory ventilation is looked upon as a lung-protective ventilation strategy. For a further clarification of the physical processes promoting gas transport, a visualization of gas flow and the distribution of ventilation are of considerable interest. Therefore, fluorine-19 magnetic resonance imaging of the imaging gas octafluorocyclobutane (C(4) F(8) ) during high-frequency oscillatory ventilation was performed in five healthy pigs. For that, a mutually compatible ventilation-imaging system was set up and transverse images were acquired every 5 sec using FLASH sequences on a 1.5 T scanner. Despite a drop in signal-to-noise ratio after the onset of high-frequency oscillatory ventilation, for each pig, the four experiments could be analyzed. A mean wash-out time (?) at 5 Hz of 52.7 ± 18 sec and 125.9 ± 39 sec at 10 Hz, respectively, were found for regions of interest including the whole lung. This is in agreement with the clinical findings, in that wash-out of respiratory gases is significantly prolonged for increased high-frequency oscillatory ventilation frequencies. Our study could be a good starting-point for a further optimization of high-frequency oscillatory ventilation. PMID:20593369

Wolf, Ursula; Scholz, Alexander; Terekhov, Maxim; Koebrich, Rainer; David, Matthias; Schreiber, Laura Maria

2010-11-01

207

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

Microsoft Academic Search

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

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

1983-01-01

208

Temperature reconstruction at the West Antarctic Ice Sheet Divide, for the last millennium, from the combination of borehole temperature and inert gas isotope measurements  

NASA Astrophysics Data System (ADS)

The study of past climates informs us on the causes, amplitude and mechanisms of climate change, which is necessary to our ability to predict future changes, and build the necessary infrastructure to ensure the resilience of our society to these changes. Local climate records contain both large scale and local signals, from both external forcing, such as radiative forcing, and internal climate variability. In order to understand the response of the climate system to global drivers, we must average out the local signals into hemispheric or global variables. This process has been difficult because we lack the spatial coverage in large areas of the Earth, including the oceans, and much of the Southern Hemisphere. The work presented here aims at improving our knowledge of the climate by producing a new temperature time series from the center of West Antarctica for the last 1000 years, a region previously unexplored. This temperature reconstruction is based on a new method, combining borehole temperature measurements with inert gas isotopes from the WAIS-Divide ice cores into a single inverse problem. Borehole temperature measurements constrain the long term changes in the climate, while inert gas isotopes record decadal to centennial scale changes. Together, they produce a temperature estimate that is independent of the traditional water isotope proxy, and provide a way to calibrate it. WAIS-Divide experienced a long term cooling trend from 950 to 1850 A.D., which ended abruptly by warming by 2.3°C in 30 years. More recently, WAIS-Divide has been warming by more than 1.5°C since 1957, which refutes the idea that Antarctica would not experience the current warming seen elsewhere. The long term cooling trend was superimposed on centennial scale variations in the climate, including two warming events, notably between 1315 and 1395 A.D., 1596 and 1626 A.D., with a warming rate of 0.24 and 0.32°C/decade. This evidence shows that the current rate of warming at WAIS-Divide, of 0.23°C/decade for the last 50 years is rare but not unprecedented. This record is consistent with the idea that the decrease in solar radiation from 1400 to 1800 A.D. induced widespread cooling in mid and high latitudes of both hemispheres.

Orsi, Anais J.

209

Film condensation of steam flowing downward on a tier of horizontal cylinders at different inclination angles in the presence of a non-condensable gas  

NASA Astrophysics Data System (ADS)

The problem of forced laminar film condensation of steam flowing downward a tier of horizontal cylinders is investigated numerically. The effects of free stream non-condensable gas, air concentration (m1,?), free stream velocity (Reynolds number), cylinder diameter, and angle of inclination on the condensation heat transfer are analyzed. Two flow arrangements, inline and staggered, are analyzed and investigated. The mathematical model takes into account the effect of staggering of the cylinders and how condensation is affected at the lower cylinders when condensate does not fall on to the center line of the cylinders. Condensation heat transfer results are available in ranges from (U? = 1 - 30 m/s) for free stream velocity, (m1,? = 0.01 -0.8) for free stream air mass fraction and (D = 12.7 -50.8 mm) for cylinder diameter. Results show that; a remarked reduction in the vapor side heat transfer coefficient is noticed. This results from the presence of small amounts of free stream air mass fractions in the steam-air mixture and increase in the cylinder diameter. On the other hand, it increases by increasing the free stream velocity (Reynolds number). Average heat transfer coefficient at the middle and the bottom cylinders increases by increasing the angle of inclination, whereas, no significant change is observed for that of the upper cylinder. Down the bank, a rapid decrease in the vapor side heat transfer coefficient is noticed. It may be resulted from the combined effects of inundation, decrease in the vapor velocity and increase in the non-condensable gas (air) at the bottom cylinders in the bank.

Ramadan, Abdulghani; Yamali, Cemil

2013-12-01

210

Phase operators and blurring time of a pair-condensed Fermi gas  

NASA Astrophysics Data System (ADS)

Due to atomic interactions and dispersion in the total atom number, the order parameter of a pair-condensed Fermi gas experiences a collapse in a time that we derive microscopically. As in the bosonic case, this blurring time depends on the derivative of the gas chemical potential with respect to the atom number and on the variance of that atom number. The result is obtained first using linearized time-dependent Bogoliubov-de Gennes equations, then in the random-phase approximation, and then it is generalized to beyond the mean field. In this framework, we construct and compare two phase operators for the paired fermionic field: The first one, issuing from our study of the dynamics, is the infinitesimal generator of adiabatic translations in the total number of pairs. The second one is the phase operator of the amplitude of the field of pairs on the condensate mode. We explain that these two operators differ due to the dependence of the condensate wave function on the atom number.

Kurkjian, H.; Castin, Y.; Sinatra, A.

2013-12-01

211

Condensate fraction and critical temperature of interacting Bose gas in anharmonic trap  

NASA Astrophysics Data System (ADS)

By using a correlated many body method and using the realistic van der Waals potential we study several statistical measures like the specific heat, transition temperature and the condensate fraction of the interacting Bose gas trapped in an anharmonic potential. As the quadratic plus a quartic confinement makes the trap more tight, the transition temperature increases which makes more favourable condition to achieve Bose-Einstein condensation (BEC) experimentally. BEC in 3D isotropic harmonic potential is also critically studied, the correction to the critical temperature due to finite number of atoms and also the correction due to inter-atomic interaction are calculated by the correlated many-body method. Comparison and discussion with the mean-field results are presented.

Haldar, Sudip Kumar; Chakrabarti, Barnali; Bhattacharyya, Satadal; Das, Tapan Kumar

2014-09-01

212

Effect of carrier gas pressure on condensation in a supersonic nozzle  

SciTech Connect

Supersonic nozzle experiments were performed with a fixed water or ethanol vapor pressure and varying amounts of nitrogen to test the hypothesis that carrier gas pressure affects the onset of condensation. Such an effect might occur if nonisothermal nucleation were important under conditions of excess carrier gas in the atmospheric pressure range, as has been suggested by Ford and Clement [J. Phys. A [bold 22], 4007 (1989)]. Although a small increase was observed in the condensation onset temperature as the stagnation pressure was reduced from 3 to 0.5 atm, these changes cannot be attributed to any nonisothermal effects. The pulsed nozzle experiments also exhibited two interesting anomalies: (1) the density profiles for the water and ethanol mixtures were shifted in opposite directions from the dry N[sub 2] profile; (2) a long transient period was required before the nozzle showed good pulse-to-pulse repeatability for condensible vapor mixtures. To theoretically simulate the observed onset behavior, calculations of nucleation and droplet growth in the nozzle were performed that took into account two principal effects of varying the carrier gas pressure: (1) the change in nozzle shape due to boundary layer effects and (2) the variation in the heat capacity of the flowing gas. Energy transfer limitations were neglected in calculating the nucleation rates. The trend of the calculated results matched that of the experimental results very well. Thus, heat capacity and boundary layer effects are sufficient to explain the experimental onset behavior without invoking energy transfer limited nucleation. The conclusions about the rate of nucleation are consistent with those obtained recently using an expansion cloud chamber, but are at odds with results from thermal diffusion cloud chamber measurements.

Wyslouzil, B.E.; Wilemski, G.; Beals, M.G.; Frish, M.B. (Physical Sciences Inc., 20 New England Business Center, Andover, Massachusetts 01810 (United States))

1994-08-01

213

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)

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.

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

2014-06-01

214

Early evaluation of uncertainties in the incremental condensate recovery through a gas cycling process  

SciTech Connect

In the case of a gas condensate reservoir assessed by two wells only, the recovery mechanism (primary depletion or gas-cycling) has not been selected yet. To succeed in the development project, the gas condensate recovery increment given by the gas-cycling option shall be completely demonstrated and above all shall not be overestimated at an early stage of the field life. With two wells only, a good many questions concerning the sedimentary model of the reservoir remain unanswered. However, two stages of diagenesis in the shallow water sandstones have been identified : the first one leads to the formation of carbonate cementation levels, the second one is a solution stage constituting drains. Given that the fundamental heterogeneity is unknown at this early stage, the modeling is based on the fact that the distinction between the cemented and non cemented levels can be easily made using logs. Two types of methods are successively used : the indicators for facies modeling, and the multigaussian method for petrophysical characteristics modeling. In order to provide contrasted models clearly showing the uncertainty associated to the geological model, two {open_quotes}end-member hypotheses{close_quotes} based on the frequency and the range of the heterogeneities have been made. Simulations carried out on a section of the reservoir only (a chronostratigraphic unit into a compartment) show that the results are sensitive to the heterogeneity range. This is particularly illustrated in the case of the gas-cycling option where the efficiency of the gas injection is much greater in the case of low range heterogeneities than the case of long range heterogeneities. One clustering method is suggested whose application demonstrates that the simulation results obtained on a fine gridded model can be reproduced using a number of layers significantly reduced.

Massonnat, G.J.; Bachtanik, C.; Tutenuit, E. [and others

1995-12-31

215

Full field reservoir modelling of Central Oman gas/condensate fields  

SciTech Connect

Gas reserves sufficient for a major export scheme have been found in Central Oman. To support appraisal and development planning of the gas/condensate fields, a dedicated, multi-disciplinary study team comprising both surface and subsurface engineers was assembled. The team fostered a high level of awareness of cross-disciplinary needs and challenges, resulting in timely data acquisition and a good fit between the various work-activities. The foundation of the subsurface contributions was a suite of advanced full-field reservoir models which: (1) provided production and well requirement forecasts; (2) quantified the impact of uncertainties on field performance and project costs; (3) supported the appraisal campaign; (4) optimised the field development plan; and (5) derived recovery factor ranges for reserves estimates. Geological/petrophysical uncertainties were quantified using newly-developed, 3-D probabilistic modelling tools. An efficient computing environment allowed a large number of sensitivities to be run in a timely, cost-effective manner. The models also investigated a key concern in gas/condensate fields: well impairment due to near-well condensate precipitation. Its impact was assessed using measured, capillary number-dependent, relative permeability curves. Well performance ranges were established on the basis of Equation of State single-well. simulations, and translated into the volatile oil full-field models using pseudo relative permeability curves for the wells. The models used the sparse available data in an optimal way and, as part of the field development plan, sustained confidence in the reserves estimates and the project, which is currently in the project specification phase.

Leemput, L.E.C. van de; Bertram, D.A.; Bentley, M.R. [and others

1995-12-31

216

Use of oil-emulsion mud in the Sivells Bend Field: Gas and gas condensate operations for the independent producer.  

E-print Network

meter ad)ustment, the following example ls offered: With a 6" x 2$" plate, using a 100"-2000$ meter set 1" slow and measuring gas at 1500 pal pressure, in excess of 1, 500 mcf/day was passing with no flow indicated on the chart. Extreme care should... are being used for the extraction of condensate, close field supervision may pay dividends. It should be remembered that llqu1d recoveries may vary consid- erably from field to field and under certain reservoir condit1ons will even vary from well to well...

Echols, Walter Harlan

2012-06-07

217

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

SciTech Connect

Condensate liquids have been found to contaminate soil and groundwater at two gas production sites in the Denver Basin operated by Amoco Production Co. These sites have been closely monitored since July 1993 to determine whether intrinsic aerobic or anaerobic bioremediation of hydrocarbons occurs at a sufficient rate and to an adequate end point to support a no-intervention decision. Groundwater monitoring and analysis of soil cores suggest that intrinsic bioremediation is occurring at these sites by multiple pathways, including aerobic oxidation Fe(III) reduction, and sulfate reduction. 2 refs., 5 figs., 1 tab.

Barker, G.W.; Raterman, K.T.; Fisher, J.B. [Amoco Production Co., Tulsa, OK (United States)]|[Univ. of Tulsa, OK (United States)] [and others

1996-12-31

218

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

NASA Astrophysics Data System (ADS)

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.

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

219

Conservation and greenhouse gas benefits of an electricity producing condensing furnace  

SciTech Connect

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.

Wicks, F.

1998-07-01

220

Biophysics of Inert Gases Related to Diving.  

National Technical Information Service (NTIS)

One of the main aims of this research is to understand from first principles what determines the solubility of a gas in liquid. In order to make this general and difficult problem more tractable, experiments studied the solubility of the inert gas Xe in s...

G. L. Pollack

1982-01-01

221

Exciton Bose condensation : the ground state of an electron-hole gas II. Spin states, screening and band structure effects  

E-print Network

1083 Exciton Bose condensation : the ground state of an electron-hole gas II. Spin states : screening corrections do not change the sign of the compressibility, which remains positive, in contrast expect a first order transition with a liquid-gas phase separation. J. Physique 43 (1982) 1083

Boyer, Edmond

222

Two-dimensional Bose gas of tilted dipoles: Roton instability and condensate depletion  

NASA Astrophysics Data System (ADS)

We predict the effect of the roton instability for a two-dimensional weakly interacting gas of tilted dipoles in a single homogeneous quantum layer. Being typical for strongly correlated systems, the roton phenomena appear to occur in a weakly interacting gas. It is important that in contrast to a system of normal to the layer dipoles, breaking of the rotational symmetry for a system of tilted dipoles leads to the convergence of the condensate depletion even up to the threshold of the roton instability, with mean-field approach being valid. Predicted effects can be observed in a wide class of dipolar systems. We suggest observing predicted phenomena for systems of ultracold atoms and polar molecules in optical lattices, and estimate optimal experimental parameters.

Fedorov, A. K.; Kurbakov, I. L.; Shchadilova, Y. E.; Lozovik, Yu. E.

2014-10-01

223

Scalar susceptibilities and four-quark condensates in the meson gas within chiral perturbation theory  

NASA Astrophysics Data System (ADS)

We analyze the properties of four-quark condensates and scalar susceptibilities in the meson gas, within finite temperature chiral perturbation theory (ChPT). The breaking of the factorization hypothesis does not allow for a finite four-quark condensate and its use as an order parameter, except in the chiral limit. This is rigorously obtained within ChPT and is therefore a model-independent result. Factorization only holds formally in the large Nc limit and breaks up at finite temperature even in the chiral limit. Nevertheless, the factorization breaking terms are precisely those needed to yield a finite scalar susceptibility, deeply connected to chiral symmetry restoration. Actually, we provide the full result for the SU(3) quark condensate to next-to-next-to- leading order in ChPT, thus extending previous results to include kaon and eta interactions. This allows us to check the effect of those corrections compared to previous approaches and the uncertainties due to low-energy constants. We provide a detailed analysis of scalar susceptibilities in the SU(3) meson gas, including a comparison between the pure ChPT approach and the virial expansion, where the unitarization of pion scattering is crucial to achieve a more reliable prediction. Through the analysis of the interactions within this approach, we have found that the role of the ? resonance is largely canceled with the scalar isospin two-channel interaction, leaving the ?(770) as the main contribution. Special attention is paid to the evolution towards chiral restoration, as well as to the comparison with recent lattice analysis.

Gómez Nicola, A.; Peláez, J. R.; de Elvira, J. Ruiz

2013-01-01

224

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

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

225

Inert gas ion source program  

NASA Technical Reports Server (NTRS)

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.

Ramsey, W. D.

1978-01-01

226

Inert gas ion thruster development  

NASA Technical Reports Server (NTRS)

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.

Ramsey, W. D.

1980-01-01

227

Process for the production of natural gas condensate having a reduced amount of mercury from a mercury containing natural gas wellstream  

Microsoft Academic Search

This patent describes a process for the production of a natural gas condensate having a reduced amount of mercury from a mercury-containing natural gas wellstream. It comprises separating the wellstream into a gaseous fraction and a liquid fraction, purifying the gaseous fraction with a carbonate solution which has the ability to absorb carbon dioxide and hydrogen sulfide, heating the resulting

C. A. Audeh; B. E. Hoffman

1992-01-01

228

Study of mine fire fighting using inert gases. Research report, 4 Jun 1973--24 Dec 1974  

Microsoft Academic Search

A theoretical evaluation was made of the usefulness of fighting coal mine fire with inert gases. A review is made of existing applications that indicate that inert gas methods of fighting mine fires are routine in Czechoslovakia and the U.S.S.R. Details are given of the calculation of inert gas requirements. If sudden ventilation changes can be avoided, the main inerting

Greuer

1974-01-01

229

Interaction-induced crossover versus finite-size condensation in a weakly interacting trapped one-dimensional Bose gas  

SciTech Connect

We discuss the transition from a fully decoherent to a (quasi)condensate regime in a harmonically trapped weakly interacting one-dimensional (1D) Bose gas. By using analytic approaches and verifying them against exact numerical solutions, we find a characteristic crossover temperature and crossover atom number that depend on the interaction strength and the trap frequency. We then identify the conditions for observing either an interaction-induced crossover scenario or else a finite-size Bose-Einstein condensation phenomenon characteristic of an ideal trapped 1D gas.

Bouchoule, I. [Laboratoire Charles Fabry, UMR 8501 du CNRS, 91 403 Orsay Cedex (France); Kheruntsyan, K. V. [ARC Centre of Excellence for Quantum-Atom Optics, School of Physical Sciences, University of Queensland, Brisbane, Queensland 4072 (Australia); Shlyapnikov, G. V. [Laboratoire de Physique Theorique et Modeles Statistiques, Universite Paris-Sud, 91405 Orsay Cedex (France); Van der Waals-Zeeman Institute, University of Amsterdam, 1018 XE Amsterdam (Netherlands)

2007-03-15

230

Methanol Droplet Combustion in Oxygen-Inert Environments in Microgravity  

NASA Technical Reports Server (NTRS)

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.

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

2013-01-01

231

Effect of the Minimal Length on Bose-Einstein Condensation in the Relativistic Ideal Bose Gas  

E-print Network

Based on the generalized uncertainty principle (GUP), the critical temperature and the Helmholtz free energy of Bose-Einstein condensation (BEC) in the relativistic ideal Bose gas are investigated. At the non-relativistic limit and the ultra-relativistic limit, we calculate the analytical form of the shifts of the critical temperature and the Helmholtz free energy caused by weak quantum gravitational effects. The exact numerical results of these shifts are obtained. Quantum gravity effects lift the critical temperature of BEC. By measuring the shift of the critical temperature, we can constrain the deformation parameter $\\beta_0$. Furthermore, at lower densities, omitting quantum gravitational effects may lead to a metastable state while at sufficiently high densities, quantum gravitational effects tend to make BEC unstable. Using the numerical methods, the stable-unstable transition temperature is found.

Zhang, Xiuming

2014-01-01

232

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

SciTech Connect

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.

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

233

Mesoscopic Effects in Bose-Einstein Condensate Fluctuations of an Ideal Gas in a Box  

E-print Network

Tc. Assuming that the degeneracy factor g = 1, one has: Tc = 3.31planckover2pi1 2 mn 2/3, (1.2) where n is the number density of the gas. Below the critical temperature the mean number of atoms ?n0 with the zero momentum p = 0 (the condensed atoms... of the operator ?nk = ?a?k?ak giving the number of atoms in the single-particle state. They obey the usual commutation relationships: [?ap,?a?k] = ?p,k, [?ak,?ap] = 0, [?a?p,?a?k] = 0. (1.26) BEC occurs when the mean number of atoms ?n0 of a particular single...

Dorfman, Konstantin Evgenievich

2009-05-15

234

Effect of the Minimal Length on Bose-Einstein Condensation in the Relativistic Ideal Bose Gas  

E-print Network

Based on the generalized uncertainty principle (GUP), the critical temperature and the Helmholtz free energy of Bose-Einstein condensation (BEC) in the relativistic ideal Bose gas are investigated. At the non-relativistic limit and the ultra-relativistic limit, we calculate the analytical form of the shifts of the critical temperature and the Helmholtz free energy caused by weak quantum gravitational effects. The exact numerical results of these shifts are obtained. Quantum gravity effects lift the critical temperature of BEC. By measuring the shift of the critical temperature, we can constrain the deformation parameter $\\beta_0$. Furthermore, at lower densities, omitting quantum gravitational effects may lead to a metastable state while at sufficiently high densities, quantum gravitational effects tend to make BEC unstable. Using the numerical methods, the stable-unstable transition temperature is found.

Xiuming Zhang; Chi Tian

2014-10-10

235

Effect of inert propellant injection on Mars ascent vehicle performance  

NASA Technical Reports Server (NTRS)

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.

Colvin, James E.; Landis, Geoffrey A.

1992-01-01

236

Wax precipitation for gas condensate fluids was studied in detail with a thermodynamic model. It was found that the precipitated  

E-print Network

Summary Wax precipitation for gas condensate fluids was studied in detail with a thermodynamic model. It was found that the precipitated wax phase can exhibit retrograde phenomena similar of precipitated wax may first increase, then decrease, then increase again. The effect of pressure on wax

Firoozabadi, Abbas

237

Method of producing hydrogen, and rendering a contaminated biomass inert  

DOEpatents

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

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

2010-02-23

238

Analytical theory of mesoscopic Bose-Einstein condensation in an ideal gas  

SciTech Connect

We find the universal structure and scaling of the Bose-Einstein condensation (BEC) statistics and thermodynamics (Gibbs free energy, average energy, heat capacity) for a mesoscopic canonical-ensemble ideal gas in a trap with an arbitrary number of atoms, any volume, and any temperature, including the whole critical region. We identify a universal constraint-cutoff mechanism that makes BEC fluctuations strongly non-Gaussian and is responsible for all unusual critical phenomena of the BEC phase transition in the ideal gas. The main result is an analytical solution to the problem of critical phenomena. It is derived by, first, calculating analytically the universal probability distribution of the noncondensate occupation, or a Landau function, and then using it for the analytical calculation of the universal functions for the particular physical quantities via the exact formulas which express the constraint-cutoff mechanism. We find asymptotics of that analytical solution as well as its simple analytical approximations which describe the universal structure of the critical region in terms of the parabolic cylinder or confluent hypergeometric functions. The obtained results for the order parameter, all higher-order moments of BEC fluctuations, and thermodynamic quantities perfectly match the known asymptotics outside the critical region for both low and high temperature limits. We suggest two- and three-level trap models of BEC and find their exact solutions in terms of the cutoff negative binomial distribution (which tends to the cutoff gamma distribution in the continuous limit) and the confluent hypergeometric distribution, respectively. Also, we present an exactly solvable cutoff Gaussian model of BEC in a degenerate interacting gas. All these exact solutions confirm the universality and constraint-cutoff origin of the strongly non-Gaussian BEC statistics. We introduce a regular refinement scheme for the condensate statistics approximations on the basis of the infrared universality of higher-order cumulants and the method of superposition and show how to model BEC statistics in the actual traps. In particular, we find that the three-level trap model with matching the first four or five cumulants is enough to yield remarkably accurate results for all interesting quantities in the whole critical region. We derive an exact multinomial expansion for the noncondensate occupation probability distribution and find its high-temperature asymptotics (Poisson distribution) and corrections to it. Finally, we demonstrate that the critical exponents and a few known terms of the Taylor expansion of the universal functions, which were calculated previously from fitting the finite-size simulations within the phenomenological renormalization-group theory, can be easily obtained from the presented full analytical solutions for the mesoscopic BEC as certain approximations in the close vicinity of the critical point.

Kocharovsky, Vitaly V. [Department of Physics, Texas A and M University, College Station, Texas 77843-4242 (United States); Institute of Applied Physics, Russian Academy of Science, RU-603950 Nizhny Novgorod (Russian Federation); Kocharovsky, Vladimir V. [Institute of Applied Physics, Russian Academy of Science, RU-603950 Nizhny Novgorod (Russian Federation)

2010-03-15

239

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

SciTech Connect

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.

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

240

Laboratory experimental testing of inerters  

Microsoft Academic Search

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

Christakis Papageorgiou; Malcolm C. Smith

2005-01-01

241

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

SciTech Connect

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.

Mohler, H.P.

1989-03-01

242

Consideration of real gas effects and condensation in a spray-combustion rocket-thrust-chamber design tool  

NASA Astrophysics Data System (ADS)

For the prediction of hot gas side heat transfer in rocket thrust chambers, Astrium Space Transportation (ST) uses the second generation multiphase Navier-Stokes solver Rocflam-II. To account for real-gas and condensation effects, pressure-dependent and even multiphase fluid data are included in the chemistry tables used by the code. Thus, the changing fluid properties near the two-phase region as well as transformation from gaseous to liquid and even solid state are reflected properly. Heat flux measurements for a dedicated subscale test campaign with strongly cooled walls show a clearly increasing heat load as soon as the combustion gases condense at the wall, due to the released latent heat of condensation. Corresponding coupled Rocflam-II/CFX simulations show a good quantitative agreement in heat flux for load cases with and without condensation, showing the ability of the code to correctly simulate flows in the real-gas and even inside the two-phase region.

Frey, M.; Kniesner, B.; Knab, O.

2011-10-01

243

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

NASA Technical Reports Server (NTRS)

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

Matsumoto, Y.

1988-01-01

244

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

SciTech Connect

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.

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

245

Dispersive and classical shock waves in Bose-Einstein condensates and gas dynamics  

SciTech Connect

A Bose-Einstein condensate (BEC) is a quantum fluid that gives rise to interesting shock-wave nonlinear dynamics. Experiments depict a BEC that exhibits behavior similar to that of a shock wave in a compressible gas, e.g., traveling fronts with steep gradients. However, the governing Gross-Pitaevskii (GP) equation that describes the mean field of a BEC admits no dissipation, hence classical dissipative shock solutions do not explain the phenomena. Instead, wave dynamics with small dispersion is considered and it is shown that this provides a mechanism for the generation of a dispersive shock wave (DSW). Computations with the GP equation are compared to experiment with excellent agreement. A comparison between a canonical one-dimensional (1D) dissipative and dispersive shock problem shows significant differences in shock structure and shock-front speed. Numerical results associated with the three-dimensional experiment show that three- and two-dimensional approximations are in excellent agreement and 1D approximations are in good qualitative agreement. Using 1D DSW theory, it is argued that the experimentally observed blast waves may be viewed as dispersive shock waves.

Hoefer, M. A.; Ablowitz, M. J. [Department of Applied Mathematics, University of Colorado, Campus Box 526, Boulder, Colorado 80309-0526 (United States); Coddington, I.; Cornell, E. A.; Engels, P.; Schweikhard, V. [JILA, National Institute of Standards and Technology, University of Colorado, Boulder, Colorado 80309-0440 (United States) and Department of Physics, University of Colorado, Boulder, Colorado 80309-0440 (United States)

2006-08-15

246

Treating of produced water for surface discharge at the Arun gas condensate field  

SciTech Connect

Mobil`s Arun Field in northern Sumatra produces natural gas, hydrocarbon liquids and water condensate. Purification of the water for surface disposal is the subject of this paper. The Arun waste water contains about 2,000 ppm of liquid hydrocarbons in the form of a very stable oil-in-water emulsion. Stability of the emulsion is enhanced by the small diameters of the oil droplets, low salt content of the water and low pH. The water is saturated with carbon dioxide and hydrocarbon gases which bubble from the water when pressure is released. Returns of acids, surfactants, emulsifying agents and corrosion inhibitors from acid fracturing operations also contribute to the composition of Arun waste water. Increases in waste water production, now about 32,000 BPD, and relatively high concentrations of BOD, phenols and ammonia have prompted Mobil to upgrade the Arun waste water treating facilities to protect the receiving bodies of water from contamination. The upgrade focused on two areas of water treating: (1) removal of suspended liquid hydrocarbons from the water; and (2) biological oxidation of dissolved organics. Demulsifier chemical and a skim tank were added to the oil removal facility; the decarbonator and caustic addition before air flotation were eliminated. Without added caustic, the gas flotation units remove acid gases from the water very effectively. The new skim tank removes over 90% of the suspended hydrocarbons. The biological oxidation ponds were upgraded by adding barriers to improved plug flow, increasing dispersed air flow, increasing sludge recycle volume, lowering the oil input and by adding nutrients and biological seeding. Results of the biological pond upgrades are not yet available because increased sludge recirculation and the optimization of biological seeding are not yet completed. Tests of the use of locally-produced biological sludge are planned.

Madian, E.S.; Moelyodihardjo, T.; Snavely, E.S.; Jan, R.J.

1995-11-01

247

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

Microsoft Academic Search

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 (24h) 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

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

2011-01-01

248

Structure and optical properties of tungsten oxide nanomaterials prepared by a modified plasma arc gas condensation technique  

Microsoft Academic Search

With the use of a modified plasma arc gas condensation technique and control of the processing parameters, namely, plasma\\u000a current and chamber pressure, we synthesized tungsten oxide nanomaterials with aspect ratios ranging from 1.1 (for equiaxed\\u000a particles with the length and width of 48 nm and 44 nm, respectively) to 12.7 (for rods with the length and width of 266 nm\\u000a and 21 nm,

Cherng-Yuh Su; Hsuan-Ching Lin; Tsung-Kun Yang; Chung-Kwei Lin

2010-01-01

249

Effects of NaOH treatment on condensed tannin contents and gas production kinetics of tree leaves  

Microsoft Academic Search

Effects of NaOH treatment on the crude protein (CP), condensed tannin (CT) and in vitro gas production kinetics of leaves of Arbutus andrachne, Glycyrrhiza glabra L. and wheat straw were determined. Wheat straw, which is tannin-free, was used as the standard. The NaOH treatment was completed by pulverization of samples with 0, 20, 40, 60 and 80g\\/L of NaOH solution

O. Canbolat; C. O. Ozkan; A. Kamalak

2007-01-01

250

Mathematical simulation of the combustion of a peat bed. Influence of steam condensation  

NASA Astrophysics Data System (ADS)

A model of the pyrolysis and combustion of a porous medium in the absence of forced convection is suggested. Substantial differences between this statement of the problem and filtration combustion of gases in inert porous media are considered. The influence of the condensation of steam contained in the products of pyrolysis on gas filtration and the temperature field close by the combustion site is shown.

Gnezdilov, N. N.; Kozlov, I. M.; Dobrego, K. V.

2012-09-01

251

Bifurcation of a Flow of a Gas between Rotating Coaxial Circular Cylinders with Evaporation and Condensation II  

NASA Astrophysics Data System (ADS)

A gas between rotating coaxial circular cylinders made of the condensed phase of the gas, where evaporation or condensation takes place is considered. The time-independent behavior of the gas is studied analytically with special interest in bifurcation of the solution in the following situation, where ``the incompressible Navier-Stokes set of equations'' is derived from the Boltzmann equation: (i) the Knudsen number is vanishingly small; (ii) the speeds of rotation of the cylinders are small and the Mach number of the gas flow is the same order as the Knudsen number (or the Reynolds number of the flow is of the order of unity); and (iii) the temperature difference of the cylinders is small (or the difference normalized by the mean temperature is of the order of the Knudsen number). The analysis is carried out with the asymptotic theory of the Boltzmann system by Sone & Aoki (1987). The bifurcation of solution from the axially symmetric and uniform solution is studied by a standard perturbation method. The relation of the parameters in the problem where the bifurcation occurs (bifurcation point) and the behavior of the solution in the neighborhood of the bifurcation point are obtained.

Sone, Yoshio; Doi, Toshiyuki

2001-11-01

252

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

E-print Network

correlation based on reservoir gas specific gravity has been attempted. The second correlation can be used to estimate the specific gravity of the gas currently in the reservoir, after some depletion, using the original reservoir gas specific gravity...

Ovalle Cortissoz, Adriana Patricia

2012-06-07

253

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

SciTech Connect

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.

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

254

Electrically conductive properties of Ag/Si composite nanoparticle assembled films prepared with a plasma–gas-condensation cluster source  

NASA Astrophysics Data System (ADS)

Ag1?x/Six composite nanoparticle assembled films were prepared using a plasma–gas-condensation cluster beam deposition apparatus. The electrical conductivity ? and Hall coefficient |RH| of Ag1?x/Six nanoparticle assembled films obey a power law of the volume fraction of Ag pAg. The marked change at around pAg = pc indicates that the percolation of Ag nanoparticles takes place at the threshold value pc. Moreover, we found that the |RH| at T = 5 K of the Ag1?x/Six nanoparticle assembled film with the closest pAg to pc is 20 times higher than that of the bulk Ag.

Kurokawa, Yuichiro; Hihara, Takehiko

2014-11-01

255

Light-induced torque for the generation of persistent current flow in atomic gas Bose-Einstein condensates  

SciTech Connect

We show that a persistent current flow in an atomic gas Bose-Einstein condensate could be realized when the system is subject to two counterpropagating Laguerre-Gaussian so-called doughnut beams, creating a toroidal trap. The theory is developed involving a two-photon process within three atomic levels leading to a quantized light-induced torque which rotates the atoms, generating an atomic current flow in the ring. We also show that it is possible for the torque to be controlled and even switched on and off by varying the frequencies of the incident light, thereby allowing a mechanism for the control of the current flow.

Lembessis, V. E. [New York College, 38 Amalias Avenue, GR-105 58, Athens (Greece); Babiker, M. [Department of Physics, University of York, York YO10 5DD (United Kingdom)

2010-11-15

256

Conversion of straight-run gas-condensate benzenes into high- octane gasolines based on modified ZSM-5 zeolites  

NASA Astrophysics Data System (ADS)

This paper describes the conversion of straight-run benzene of gas condensate into high-octane gasoline based on zeolite catalyst ZSM-5, modified in binary system oxide- based Sn (III) and Bi (III). It was defined that the introduction of the binary system oxide-based Sn(III) and Bi (III) into the basic zeolite results in the 2-fold increase of its catalytic activity.High-octane gasoline converted from straight-run benzene is characterized by a low benzol content in comparison to the high-octane benzenes produced during the catalytic reforming.

Erofeev, V.; Reschetilowski, V.; Tatarkina, A.; Khomajakov, I.; Egorova, L.; Volgina, T.

2014-08-01

257

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

NASA Astrophysics Data System (ADS)

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

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

2007-09-01

258

On the effect of the thermal gas component to the stability of vortices in trapped Bose-Einstein condensates  

E-print Network

We study the stability of vortices in trapped single-component Bose-Einstein condensates within self-consistent mean-field theories--especially we consider the Hartree-Fock-Bogoliubov-Popov theory and its recently proposed gapless extensions. It is shown that for sufficiently repulsively interacting systems the anomalous negative-energy modes related to vortex instabilities are lifted to positive energies due to partial filling of the vortex core with noncondensed gas. Such a behavior implies that within these theories the vortex states are eventually stable against transfer of condensate matter to the anomalous core modes. This self-stabilization of vortices, shown to occur under very general circumstances, is contrasted to the predictions of the non-self-consistent Bogoliubov approximation, which is known to exhibit anomalous modes for all vortex configurations and thus implying instability of these states. In addition, the shortcomings of these approximations in describing the properties of vortices are analysed, and the need of a self-consistent theory taking properly into account the coupled dynamics of the condensate and the noncondensate atoms is emphasized.

S. M. M. Virtanen; M. M. Salomaa

2002-03-12

259

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

EPA Science Inventory

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

260

Failure analysis of cooling water pipes used in the condensation system of a gas turbine  

Microsoft Academic Search

The copper–zinc alloy pipes used in the condensed water system of a power plant failed within a period of 5 to 6 years. Because the service life of such a system was expected to be on the order of 20 years, an investigation was carried out to determine the possible causes for early failure of the pipes. Visual inspection revealed that the

Havva Kazdal Zeytin

2008-01-01

261

Cloud Condensation in Titan's Lower Stratosphere  

NASA Technical Reports Server (NTRS)

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

Romani, Paul N.; Anderson, Carrie M.

2011-01-01

262

Assessment of the effect of development of the Bovanenkovskoe gas-condensate field in the middle Yamal region on the dynamics of the polar fox population  

SciTech Connect

Based on the findings of integrated monitoring research, the state of polar fox population in a zone of heavy technogenic pressure is assessed experimentally. Networks of breeding burrows on permanent experimental and control plots were carefully examined over the course of three summer seasons. Active development of the Bovanenkovskoe gas-condensate field has led to loss of the central portion of this area as a zone of polar fox restocking. Heavy accelerated exploitation of other gas and gas-condensate fields in the Yamal Peninsula may lower the Yamal population of polar fox to the verge of extinction. 15 refs.

Dobrinskii, N.L.; Sosin, V.F. [Institute of Animal and Plant Ecology, Ekaterinburg (Russian Federation)

1995-05-01

263

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

SciTech Connect

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

Kelley, P.A.; Imbus, S.W. [Texaco E& P Technology, Houston, TX (United States); McKeever, S.R. [Texaco E& P Inc., New Orleans, LA (United States)

1995-12-31

264

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

NASA Astrophysics Data System (ADS)

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.

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

2013-05-01

265

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

PubMed Central

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

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

266

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

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

267

Dynamics of gas condensate removal from an Al-Fe-humus podzol and its effect on the complexes of soil fungi  

NASA Astrophysics Data System (ADS)

The time period for the removal of gas condensate from the cultivated and forest Al-Fe-humus podzols in the northwestern region of Russia was determined in an experiment. The content of the light fractions of oil decreased more slowly in the forest soil than in the cultivated soil due to the lower rates of evaporation and photochemical reactions under the forest canopy. During the first five days after applying the gas condensate, its content decreased by nearly 70% in the cultivated soils and by only 8% in the forest soil. In three months of the growing period, the gas condensate was completely removed from the cultivated soils and by 91% from the forest soil. The species composition and structure of the fungal communities significantly changed in the polluted soils with an increase in the portion of conventionally pathogenic fungi from 45% in the control soil to 60-70% in the polluted soil.

Evdokimova, G. A.; Korneikova, M. V.; Myazin, V. A.

2013-03-01

268

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

PubMed

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

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

2013-07-01

269

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

NASA Astrophysics Data System (ADS)

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

Gao, Lin

270

Turbulent condensation on a cold wall in the presence of a noncondensable gas  

SciTech Connect

A condensation model for forced and natural convection is derived by extending the Reynolds-Colburn analogy for heat and momentum transfer to mass and momentum transfer. The model is compared to the steady-state data of Uchida and Tagami and found to be in reasonable agreement with the forced convection data when an imposed velocity of 2 m/s is assumed. The natural convection model has the same functional dependence on Grashof number (h /SUB tot/ aboutGr /SUP -0.37/ ) as the data of Akers.

Corradini, M.L.

1984-02-01

271

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

PubMed

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

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

2011-11-01

272

Electrolyte vapor condenser  

DOEpatents

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.

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

1983-02-08

273

Electrolyte vapor condenser  

DOEpatents

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.

Sederquist, Richard A. (Newington, CT); Szydlowski, Donald F. (East Hartford, CT); Sawyer, Richard D. (Canton, CT)

1983-01-01

274

Phenomenological Modeling of Critical Condensate Saturation and  

E-print Network

Phenomenological Modeling of Critical Condensate Saturation and Relative Permeabilities in Gas critical condensate saturation and relative permeability. Relative permeability at some saturations may be due to the shape of the gas phase relative permeability (krg); the mechanisms of gas productivity

Firoozabadi, Abbas

275

Crystallization of Ge2Sb2Te5 nanometric phase change material clusters made by gas-phase condensation  

NASA Astrophysics Data System (ADS)

The crystallization behavior of Ge2Sb2Te5 nanometric clusters was studied using X-ray diffraction with in situ annealing. Clusters were made using a sputtering gas-phase condensation source, which allowed for the growth of well-defined, contaminant-free, and isolated clusters. The average size for the clusters is 5.7 ± 1 nm. As-deposited amorphous clusters crystallize in the fcc cubic phase at 180 °C, while for thin films, the phase change temperature is 155 °C. This observation illustrates the scalability of the Ge2Sb2Te5 phase change from the amorphous to the cubic state in three-dimensionally confined systems in this size range.

Ghezzi, G. E.; Morel, R.; Brenac, A.; Boudet, N.; Audier, M.; Fillot, F.; Maitrejean, S.; Hippert, F.

2012-12-01

276

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

SciTech Connect

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.

Idelovici, J.L.

1993-07-01

277

SiO(x) nanoparticles synthesized by an evaporation and condensation process using induction melting of silicon and gas injection.  

PubMed

SiO(x) nanoparticles were synthesized using a specially designed induction melting system equipped with a segmented graphite crucible. The graphite crucible with the segmented wall was the key to enhancing the evaporation rate due to the increase of the evaporation area and convection of the silicon melt. Injection of the gas mixture of oxygen (O2) and argon (Ar) on silicon (Si) melt caused the formation of SiO(x) nanoparticles. The evaporated SiO(x) nanoparticles were then cooled and condensed in a process chamber. The effects of the O2/Ar ratio in the injection gas on the microstructures of the SiO(x) nanoparticles were then investigated. Synthesized SiO(x) nanoparticles were proven to be of a homogeneous amorphous phase with average diameters of 30-35 nm. The microstructures were independent from the O2/Ar ratio of the injected gas. However, x increased from 1.36 to 1.84 as the O2/Ar ratio increased. The purity of the synthesized nanoparticles was about 99.9%. SiO(x) nanoparticles could be applied as the active anode material in a lithium (Li) ion secondary battery. PMID:23858929

Jang, Bo Yun; Lee, Jin Seok; Kim, Joon Soo

2013-05-01

278

Measurement of total fraction condensed and phase boundary for a simulated natural gas. Research report  

Microsoft Academic Search

The experimental investigation summarized in RR-56 completes a multiyear effort under Project 737 to obtain vapor-liquid equilibria of assessed accuracy on simulated natural gas systems representative of cryogenic gas processing. The current system consisting of four components, nitrogen, methane, ethane, and propane, was studied in the pressure-temperature region commensurate with turboexpander outlet conditions. The primary intent of Project 737 is

J. L. Oscarson; B. Saxey

1982-01-01

279

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

280

Sampling and Analysis Procedures for Gas, Condensate, Brine, and Solids: Pleasant Bayou Well Test, 1988-Present  

SciTech Connect

This section covers analyses performed on gas. Chemical analyses can only be related to well performance if the quantity of the various fluids are known. The IGT on-line data computer system measures the flowrate, the pressures, and the temperatures every 10 seconds. These values are automatically recorded over operator selected intervals both on magnetic media and on paper. This allows review of samples versus operating conditions. This paper covers analyses performed on gas, including: An approximate sampling schedule during flow tests; On-site sample handling and storage of gas samples; Addresses of laboratories that perform off site analyses; Sample shipping instructions; Data archiving; and Quality Control/Quality Assurance. It is expected that the above procedures will change as the flow test progresses, but deviations from the written procedures should be approved by C. Hayden of IGT and noted on the results of the analysis.

Hayden, Chris

1988-01-01

281

Local heat transfer coefficients for forced-convection condensation of steam in a vertical tube in the presence of a noncondensable gas  

SciTech Connect

An experimental investigation has been conducted to determine the local condensation heat transfer coefficient (HTC) of steam in the presence of air or helium flowing downward inside a 46-mm-i.d. vertical tube. The gas-steam mixture flow rate was measured with a calibrated vortex flowmeter before it entered the 2.54-m-long test condenser. Cooling water flow rate in an annulus around the tube was measure with a calibrated rotameter. Temperatures of the cooling water, the gas-steam mixture, and the tube inside and outside surfaces were measured at 0.3-m intervals in the test condenser. Inlet and exit pressures and temperatures of the gas-steam mixture and of the cooling water were also measured. The local heat flux was obtained from the slope of the coolant axial temperature profile and the coolant mass flow rate. It was found that for the same mass fraction of the noncondensable gas, compared with air, helium has a more inhibiting effect on the heat transfer, but for the same molar ratio, air was found to be more inhibiting. An application where there is important is the proposed advanced passive boiling water reactor design (Simplified Boiling Water Reactor), which utilizes the isolation condenser as a main component of the passive containment cooling system (PCCS).

Siddique, M.; Golay, M.W.; Kazimi, M.S. (Massachusetts Inst. of Tech., Cambridge (United States))

1993-06-01

282

-Based Cermet Inert Anodes for Aluminum Electrolysis  

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

283

Analysis on Pipe Rupture of Steam Condensing Line at Hamaoka-1, (I) Accumulation of Non-condensable Gas in a Pipe  

Microsoft Academic Search

A pipe rupture occurred in the steam condensing line of the residual heat removal system at the Hamaoka Nuclear Power Station Unit-1 on November 7, 2001. The detonation of the hydrogen accumulated in the pipe was considered to be the likeliest cause of the rupture. As the first step of the accident analysis, fluid behavior in the line was analyzed

Masanori NAITOH; Fumio KASAHARA; Toshiharu MITSUHASHI; Iwao OHSHIMA

2003-01-01

284

Condensed Lecture Notes (Part 3) Hydrogen is the most abundant element in the universe. It is a transparent gas under normal conditions.  

E-print Network

18 Condensed Lecture Notes (Part 3) Hydrogen Hydrogen is the most abundant element in the universe. It is a transparent gas under normal conditions. It can form both a cation (H+ ) and an anion (H- ). It is made a nickel catalyst) CH4 + H2O CO + 3H2 (2) water gas-shift reaction (iron/copper catalyst) CO + H2O CO2

285

Flame extinguishing in the cup-burner by inert gases  

Microsoft Academic Search

National and international standards on gaseous fire extinguishing systems specify the minimum design concentrations of gaseous agents for flammable liquid hazards based on extinguishing concentrations determined by the cup-burner method. Extinguishing concentration values, XG, reported in standards documents do not correlate as well as expected with heat capacity, the underlying figure of merit for inert gas agents, a result that

Joseph A. Senecal

2005-01-01

286

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...

287

Enhanced production from a slightly geopressured water-drive gas condensate field  

SciTech Connect

The production history of a Texas Gulf Coast Frio water drive gas field is presented, including performance data from a well which was recently restored to commercial production after having been abandoned six years. Areas of additional study which would help forecast future performance are discussed.

Anderson, L.L.; Parisi, W.A.; Peterson, K.P.

1984-05-01

288

Recovery of Water from Boiler Flue Gas Using Condensing Heat Exchangers  

Microsoft Academic Search

Most of the water used in a thermoelectric power plant is used for cooling, and DOE has been focusing on possible techniques to reduce the amount of fresh water needed for cooling. DOE has also been placing emphasis on recovery of usable water from sources not generally considered, such as mine water, water produced from oil and gas extraction, and

Edward Levy; Harun Bilirgen; John DuPoint

2011-01-01

289

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

NASA Technical Reports Server (NTRS)

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.

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

290

Simulations and parameter variation studies of heavy gas dispersion using the SLAB model - condensed  

SciTech Connect

We are employing the SLAB model in ongoing studies of the atmospheric dispersion of heavy gases. SLAB computer simulations of four of the Burro series large-scale 40-m/sup 3/ liquefied natural gas (LNG) spill experiments at China Lake, California have been successful in predicting distances to the lower flammability limit (LFL). WE have used this model in simulations of three of the Coyote series of experiments as well as in parameter variation and sensitivity studies and improved simulations of some of the Burro tests. The parameters studied include source rate, wind speed, atmospheric stability, type of source gas, and source duration, as well as the parameters important to certain physics submodels. 8 references, 5 figures.

Morgan, D.L. Jr.; Kansa, E.J.; Morris, L.K.

1983-12-01

291

Influence of the bath gas on the condensation of supersaturated iron atom vapour at room temperature  

Microsoft Academic Search

The influence of the kind of bath gas and its pressure on the iron nanoparticle formation and growth was investigated experimentally. Iron nanoparticles were synthesized from supersaturated iron vapour generated by ArF excimer laser pulse photolysis of gaseous Fe(CO)5 at room temperature. The particle size was determined by time-resolved laser-induced incandescence (TiRe-LII) as a function of time after photolysis at

A. Eremin; E. Gurentsov; C. Schulz

2008-01-01

292

Gas chromatographic determination of residual hydrazine and morpholine in boiler feed water and steam condensates  

Microsoft Academic Search

Hydrazine, an oxygen scavenger in boiler water, was derivatised to the corresponding acetone azine and determined at the ng ml?1 level by gas chromatography. Morpholine, a corrosion inhibitor used in steam boilers, was estimated either directly (if >2.0 ?g ml?1) or by quantitative preconcentration (0.1 ng – 2.0 ?g ml?1). To obtain symmetrical peaks for these amines, the column packing

S. Vatsala; V. Bansal; D. K. Tuli; M. M. Rai; S. K. Jain; S. P. Srivastava; A. K. Bhatnagar

1994-01-01

293

DNA condensation  

Microsoft Academic Search

Recent progress in our understanding of DNA condensation includes the observation of the collapse of single DNA molecules, greater insights into the intermolecular forces driving condensation, the recognition of helix-structure perturbation in condensed DNA, and the increasing recognition of the likely biological consequences of condensation. DNA condensed with cationic liposomes is an efficient agent for the transfection of eukaryotic cells,

Victor A Bloomfield

1996-01-01

294

Hot-spot combustion of heterogeneous condensed mixtures. Thermal percolation  

Microsoft Academic Search

A model of combustion of heterogeneous condensed mixtures composed of reactive particles separated by an inert heat-conducting substance is considered. Propagation of the reaction in a one-dimensional periodic system of point reaction cells connected by inert thermal bridges is examined. The burning rate is determined as a function of the basic parameters of the system, and stability of the steady

S. A. Rashkovskii

2005-01-01

295

7 CFR 201.19 - Inert matter.  

...2014-01-01 2014-01-01 false Inert matter. 201.19 Section 201.19 Agriculture...Agricultural Seeds § 201.19 Inert matter. The label shall show the percentage by weight of inert matter. [5 FR 31, Jan. 4,...

2014-01-01

296

Measurement of reactive and condensable gas permeation using a mass spectrometer  

SciTech Connect

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

Zhang Xiaodong; Lewis, Jay S.; Parker, Charles B.; Glass, Jeffrey T.; Wolter, Scott D. [Pratt School of Engineering, Duke University, Durham, North Carolina 27708 (United States); RTI International, Research Triangle Park, North Carolina 27709 (United States); Pratt School of Engineering, Duke University, Durham, North Carolina 27708 (United States)

2008-09-15

297

Hydro-gravitational fragmentation, diffusion and condensation of the primordial plasma, dark-matter and gas  

E-print Network

The first structures were proto-voids formed in the primordial plasma. Viscous and weak turbulence forces balanced gravitational forces when the scale of causal connection at time 30,000 years matched the viscous and turbulent Schwarz scales of hydro-gravitational theory (Gibson 1996). The photon viscosity allows only weak turbulence from the Reynolds number Re = 200, with fragmentation to give proto-supercluster voids, buoyancy forces, fossil vorticity turbulence, and strong sonic damping. The expanding, cooling, plasma continued fragmentation to proto-galaxy-mass with the density and rate-of-strain preserved as fossils of the weak turbulence and first structure. Turbulence fossilization by self-gravitational buoyancy explains the cosmic microwave background temperature fluctuations, not sonic oscillations in cold-dark-matter fragments. After plasma to gas transition at 300,000 years, gas fragmentation occurred within the proto-galaxies to form proto-globular-star-cluster (PGCs) clouds of small-planetary-mass primordial-fog-particles (PFPs). Dark PGC clumps of frozen PFPs persist as the inner-galaxy-halo dark matter, supporting Schild's 1996 quasar-microlensing interpretation. Non-baryonic dark matter diffused into the plasma proto-cluster-voids and later fragmented as outer-galaxy-halos at diffusive Schwarz scales, indicating light, weakly-collisional fluid particles (possibly neutrinos). Observations support the theory (Gibson and Schild 2003).

Carl H. Gibson

1999-11-15

298

Thermodynamic properties of a condensed 39K Bose gas in a harmonic trap  

NASA Astrophysics Data System (ADS)

In this paper, the thermodynamic behavior of a 39K Bose gas with a finite number of atoms confined in a harmonic potential is investigated. By taking into account the conservation of the total number of particles N and using a modified semiclassical approximation, we derive analytically the simple explicit expression for the thermal atoms number in the excited state. This modification assures to include, finite size and indirectly the interatomic interaction effects simultaneously. Various experimental, the critical atoms number and its corresponding temperature are predicted via the graphical representation. The calculated results show that the thermodynamical parameters depend critically on the size, shape, and harmonic nature of the potential. The calculated critical atoms number are coincide with the measured experimental results for 39K, as reported in Tammuz et al. [3] and Smith et al. [4].

El-Badry, Azza M.; Hassan, Ahmed S.; Soliman, Shemi S. M.

2013-02-01

299

The effect of processing parameters on the synthesis of tungsten oxide nanomaterials by a modified plasma arc gas condensation technique.  

PubMed

In the present study, tungsten oxide nanomaterials were synthesized by a modified plasma arc gas condensation technique. The effects of processing parameters (plasma current ranged from 70-90 A and chamber pressure ranged from 200-600 torr) on the preparation of tungsten oxide nanomaterials were investigated. X-ray diffraction results showed that all of the nanomaterials synthesized in the present study exhibited W5O14 phase. Field emission scanning electron microscopy and transmission electron microscopy examinations revealed that the tungsten oxide nanomaterials were equiaxed when prepared at a relatively low plasma current of 70 A, and turned into rod-like nanoparticles with increasing plasma current (80 or 90 A). Generally, the relative amount, diameter, and length of tungsten oxide nanorods increased with increasing plasma currents or chamber pressures. The aspect ratio of the as-prepared tungsten oxide nanorods reached a maximum of 12.7 when a plasma current of 90 A and a chamber pressure of 400 torr were used. A growth mechanism for tungsten oxide nanorods was proposed. PMID:21125919

Su, Cherng-Yuh; Lin, Hsuan-Ching; Yang, Tsung-Kun; Lin, Chung-Kwei

2010-08-01

300

The role of the C2 gas in the emergence of C60 from the condensing carbon vapour  

NASA Astrophysics Data System (ADS)

A model has been developed that illustrates C60's emergence from the condensing carbon vapour. It is shown to depend upon (i) the decreasing heats of formation for larger cages; (ii) exponentially increasing number of isomers for fullerenes that are larger than C60; (iii) large cages' buckling induced by the pentagon-related protrusions that initiate fragmentation; (iv) the structural instability-induced fragmentation that shrinks large cages via C x ? C x-2 + C2; and (v) an evolving gas of C2 that is crucial to the whole process. The model describes a mechanism for the provision and presence of plenty of C2s during the formation and fragmentation processes. Fullerenes portrayed as 3D rotors have partition functions describing ensemble's entropy as a function of the fragmentation sequence. The bottom-up formations of large cages followed by the top-down cage shrinkage are shown to be stable, dynamical processes that lead to the C60 dominated fullerene ensemble.

Ahmad, Shoaib; Yaqub, Kashif; Ashraf, Afshan

2013-03-01

301

Inert doublet model and LEP II limits  

SciTech Connect

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

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

2009-02-01

302

Method for removing metal vapor from gas streams  

DOEpatents

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.

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

1996-01-01

303

Method for removing metal vapor from gas streams  

DOEpatents

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.

Ahluwalia, R.K.; Im, K.H.

1996-04-02

304

Study on the Thermoelectric Properties of CVD SiC Deposited with Inert Gases  

NASA Astrophysics Data System (ADS)

We deposited silicon carbide (SiC) by the chemical vapor deposition (CVD) method using the inert gases Ar and He. It was confirmed that SiC deposited with inert gases had a porous microstructure and high carbon content. We also studied the thermoelectric properties. SiC deposited with He gas had lower electrical and thermal conductivity compared with SiC deposited with Ar gas. Both samples using Ar and He exhibited a negative Seebeck coefficient, indicating n-type semiconductor behavior. The calculated figure of merit ( Z) of SiC deposited with inert gases was improved compared with SiC deposited with H2 or N2 gas. The value for SiC deposited with He was higher than that for SiC deposited with Ar. The thermoelectric properties of porous silicon carbide deposited with inert gases were also compared with those of silicon carbide deposited with hydrogen or nitrogen gas.

Kim, Jun Gyu; Choi, You Youl; Choi, Doo Jin; Choi, Soon Mok

2011-05-01

305

The thermodynamic efficiency of the condensing process circuits of binary combined-cycle plants with gas-assisted heating of cycle air  

NASA Astrophysics Data System (ADS)

The thermal efficiencies of condensing-type circuits of binary combined-cycle plants containing one, two, and three loops with different pressure levels and equipped with a GTE-160 (V94.2) gas turbine unit, and with preheating of cycle air are analyzed by way of comparison in a wide range of initial steam pressures. The variation of the combined-cycle plant efficiency, stream wetness, conditional overall heating surface of the heat-recovery boiler, and other parameters is presented.

Kovalevskii, V. P.

2011-09-01

306

Universal scaling in the statistics and thermodynamics of a Bose-Einstein condensation of an ideal gas in an arbitrary trap  

NASA Astrophysics Data System (ADS)

We analytically calculate the critical phenomena of a Bose-Einstein condensation of an ideal gas in an arbitrary trap with any mesoscopic or macroscopic number of particles and find all universality classes of the system's statistics and thermodynamics. In particular, we find analytically the universal fine structure of the famous discontinuity in the value or/and derivative of the specific heat in the critical region around the ? point.

Tarasov, S. V.; Kocharovsky, Vl. V.; Kocharovsky, V. V.

2014-09-01

307

The Pumpless Alternative to Condensate Return  

E-print Network

THE PUMPLESS ALTERNATIVE TO CONDENSATE RETURN Michael L. Sneary The Johnson Corporation Three Rivers, MI Michael G. Buchanan The Johnson Corporation Three Rivers, MI ABSTRACT In the pumpless system we use the positive displacement concept thus... Positive pressure has been used since the beginning of time to move objects. For condensate service, the positive pressure or motive pressure is generally steam or compressed air. Other inert gases may al s 0 be used. The pump ing device is called a...

Sneary, M. L.; Buchanan, M. G.

308

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

E-print Network

compositional model at the beginning of the simulation. Unrealistic vaporization in the MBO model was encountered in both natural depletion and cycling cases. Oil saturation profiles illustrated the differences in condensate saturation distribution for the near...

Izgec, Bulent

2004-09-30

309

Flammability limits of dusts: Minimum inerting concentrations  

SciTech Connect

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.

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

310

Relation between biomarkers in exhaled breath condensate and internal exposure to metals from gas metal arc welding.  

PubMed

Concerning possible harmful components of welding fumes, besides gases and quantitative aspects of the respirable welding fumes, particle-inherent metal toxicity has to be considered.The objective of this study was to investigate the effect markers leukotriene B4 (LTB4),prostaglandin E2 (PGE2) and 8-isoprostane (8-Iso PGF2?) as well as the acid–base balance(pH) in exhaled breath condensate (EBC) of 43 full-time gas metal arc welders (20 smokers) in relation to welding fume exposure. We observed different patterns of iron, chromium and nickel in respirable welding fumes and EBC. Welders with undetectable chromium in EBC(group A, n = 24) presented high iron and nickel concentrations. In this group, higher 8-isoPGF2? and LTB4 concentrations could be revealed compared to welders with detectable chromium and low levels of both iron and nickel in EBC (group B): 8-iso PGF2?443.3 pg mL?1 versus 247.2 pg mL?1; p = 0.001 and LTB4 30.5 pg mL?1 versus 17.3 pgmL?1; p = 0.016. EBC-pH was more acid in samples of group B (6.52 versus 6.82; p = 0.011).Overall, effect markers in welders were associated with iron concentrations in EBC according to smoking habits--non-smokers/smokers: LTB4 (rs = 0.48; p = 0.02/rs = 0.21; p = 0.37),PGE2 (rs = 0.15; p = 0.59/rs = 0.47; p = 0.07), 8-iso PGF2? (rs = 0.18; p = 0.54/rs = 0.59;p = 0.06). Sampling of EBC in occupational research provides a matrix for the simultaneous monitoring of metal exposure and effects on target level. Our results suggest irritative effects in the airways of healthy welders. Further studies are necessary to assess whether these individual results might be used to identify welders at elevated risk for developing a respiratory disease. PMID:22622358

Hoffmeyer, Frank; Raulf-Heimsoth, Monika; Weiss, Tobias; Lehnert, Martin; Gawrych, Katarzyna; Kendzia, Benjamin; Harth, Volker; Henry, Jana; Pesch, Beate; Brüning, Thomas

2012-06-01

311

Propagation of first and second sound in a highly elongated trapped Bose-condensed gas at finite temperatures  

NASA Astrophysics Data System (ADS)

We study sound propagation in Bose-condensed gases in a highly elongated harmonic trap at finite temperatures. This problem is studied within the framework of the Zaremba-Nikuni-Griffin (ZNG) formalism, which consists of a generalized Gross-Pitaevskii equation for the condensate and a kinetic equation for the thermal cloud. We extend the ZNG formalism to deal with a highly anisotropic trap potential and use it to simulate sound propagation using the trap parameters corresponding to an experiment on sound pulse propagation at finite temperature. We focus on the high-density two-fluid hydrodynamic regime, and explore the possibility of observing first- and second-sound pulse propagation. The results of numerical simulation are compared with analytical results derived from linearized ZNG hydrodynamic equations. We show that the second-sound mode makes the dominant contribution to condensate motion at relatively high temperature, while the first-sound mode makes an appreciable contribution.

Arahata, Emiko; Nikuni, Tetsuro

2013-03-01

312

A dynamic inert metal anode.  

SciTech Connect

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.

Hryn, J. N.

1998-11-09

313

Gamma Inert Sterilization: A Solution to Polyethylene Oxidation?  

PubMed Central

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

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

2009-01-01

314

Effect of spontaneous condensation on condensation heat transfer in the presence of non-condensable gases  

SciTech Connect

The presence of non condensable gases like nitrogen or air reduces the condensation heat transfer during condensation of binary steam mixtures. The non condensable gas accumulates in the vapor phase boundary layer and causes a high heat transfer resistance. Especially with high pressures and low water temperatures spontaneous condensation reduces heat transfer additionally. Fog forms within the steam-nitrogen boundary layer and the steam condenses on the water droplets of the fog layer. The convective mass transfer to the cooling water interface diminishes. Raman spectroscopy and film theory are used to quantify this effect locally. The calculation of overall condensation rates in large steam nitrogen systems requires to use three dimensional CFD codes. The paper presents equations to predict fog formation in the boundary layer which can be implemented in CFD codes.

Karl, J.; Hein, D.

1999-07-01

315

Numerical evaluation of surface condensers for geothermal power plants  

Microsoft Academic Search

The transport and partitioning of gases in four surface condensers for geothermal power plants has been modelled numerically. A vent condenser between the main condenser and the first stage gas ejectors improves hydrogen sulphide partitioning, particularly if the condensate from it, and from the inter- and aftercondensers, is recirculated to the main condenser tube bundles. Regardless of steam composition, hydrogen

O WERES

1984-01-01

316

Effect of precursor supply on structural and morphological characteristics of fe nanomaterials synthesized via chemical vapor condensation method.  

PubMed

Various physical, chemical and mechanical methods, such as inert gas condensation, chemical vapor condensation, sol-gel, pulsed wire evaporation, evaporation technique, and mechanical alloying, have been used to synthesize nanoparticles. Among them, chemical vapor condensation (CVC) has the benefit of its applicability to almost all materials because a wide range of precursors are available for large-scale production with a non-agglomerated state. In this work, Fe nanoparticles and nanowires were synthesized by chemical vapor condensation method using iron pentacarbonyl (Fe(CO)5) as the precursor. The effect of processing parameters on the microstructure, size and morphology of Fe nanoparticles and nanowires were studied. In particular, we investigated close correlation of size and morphology of Fe nanoparticles and nanowires with atomic quantity of inflow precursor into the electric furnace as the quantitative analysis. The atomic quantity was calculated by Boyle's ideal gas law. The Fe nanoparticles and nanowires with various diameter and morphology have successfully been synthesized by the chemical vapor condensation method. PMID:22524015

Ha, Jong-Keun; Ahn, Hyo-Jun; Kim, Ki-Won; Nam, Tae-Hyun; Cho, Kwon-Koo

2012-01-01

317

Evidence for a palaeo-oil column and alteration of residual oil in a gas-condensate field: Integrated oil inclusion and experimental results  

NASA Astrophysics Data System (ADS)

In the Phuong Dong gas condensate field, Cuu Long Basin, Vietnam, hydrocarbon inclusions in quartz trapped a variety of petroleum fluids in the gas zone. Based on the attributes of the oil inclusion assemblages (fluorescence colour of the oil, bubble size, presence of bitumen), the presence of a palaeo-oil column is inferred prior to migration of gas into the reservoir. When a palaeo-oil column is displaced by gas, a residual volume fraction of oil remains in pores. If the gas does not completely mix with the oil, molecular partitioning between the residual oil and the new gas charge may change the composition and properties of the residual oil (gas stripping or gas washing). To simulate this phenomenon in the laboratory, we sealed small amounts of crude oil (42 and 30 °API) and excess pure gas (methane, ethane, or propane) in fused silica capillary capsules (FSCCs), with and without water. These mixtures were characterized with the same methods used to characterize the fluid inclusions, heating and cooling stage microscopy, fluorescence spectroscopy, synchrotron FT-IR, and Raman spectroscopy. At room temperature, mixtures of ethane and propane with the 30 °API oil formed a new immiscible fluorescent liquid phase with colour that is visually more blue than the initial oil. The fluorescence of the original oil phase shifted to yellow or disappeared with formation of semi-solid residues. The blue-shift of the fluorescence of the immiscible phases and strong CH stretching bands in FT-IR spectra are consistent with stripping of hydrocarbon molecules from the oil. In experiments in FSCCs with water solid residues are common. At elevated temperature, reproducing geologic reservoir conditions, the fluorescence changes and therefore the molecular fractionation are enhanced. However, the precipitation of solid residues is responsible of more complex changes. Mixing experiments with the 42 °API oil do not form a new immiscible hydrocarbon liquid although the fluorescence displays a similar yellow shift when gas is added. Solid residues rarely form in mixtures with 42 °API oil. FT-IR spectra suggest that the decrease of fluorescence intensity of the original oil at short wavelengths to be due to the partitioning of low molecular weight aromatic molecules into the vapour phase and/or the new immiscible liquid phase. The decrease of fluorescence intensity at long wavelengths appears to be due to loss of high molecular weight aromatics during precipitation of solid residues by desorption of aromatics and resins from asphaltenes. Desorption of low molecular weight aromatics and resins from asphaltenes during precipitation can also increase the fluorescence intensity at short wavelengths of the residual oil. Water clearly affects the precipitation of semi-solid residues from the oil phase of the lowest API gravity oil. The change of hydrocarbon phase(s) in UV-visible fluorescence and FT-IR enclosed within the FSCCs were compared with the fluorescence patterns of natural fluid inclusions at Phuong Dong gas condensate field. The experimental results support the concept of gas-washing of residual oil and are consistent with the oil inclusion attributes from the current gas zone at Phuong Dong field. The hydrocarbon charge history of the fractured granite reservoir is interpreted to result from the trapping of residual oil after drainage of a palaeo-oil column by gas.

Bourdet, Julien; Burruss, Robert C.; Chou, I.-Ming; Kempton, Richard; Liu, Keyu; Hung, Nguyen Viet

2014-10-01

318

Many-body dimensional perturbation theory for quantum confined systems with a focus on atomic gas Bose-Einstein condensates  

NASA Astrophysics Data System (ADS)

Systems that involve N identical, interacting particles under quantum confinement appear throughout many areas of physics, including chemical, condensed matter, and atomic physics. In this thesis, we present the methods of dimensional perturbation theory, a powerful set of tools that uses symmetry to yield simple results for studying such many-body systems. We present a detailed discussion of the dimensional continuation of the N-particle Schrodinger equation, the D ? infinity equilibrium structure, and the normal-mode oscillations of this structure. We use the Wilson FG matrix method to derive general, analytical expressions for the many-body normal-mode vibrational frequencies, and we give analytical results for three N-body quantum-confined systems: the N-electron atom, N-electron quantum dot, and N-atom inhomogeneous Bose-Einstein condensate with a repulsive hard-core potential. The focus of this thesis will be on the many-body physics of Bose-Einstein condensates (BEC). The achievement of BEC in magnetically trapped alkali-metal atoms in 1995 has generated a considerable amount of experimental and theoretical activity in recent years. In typical BEC experiments, the average distance between the bose atoms is much larger than the range of the atomic interactions, and hence, the properties of these weakly interacting condensates have been successfully described by the mean-field nonlinear Gross-Pitaevskii equation. Recently, however, no longer restricted to the atom's natural interaction parameter, experimentalists have created condensates with a "knob" (i.e., a Feshbach resonance) that allows them to adjust the interaction to whatever strength, repulsive or attractive, they wish. These strongly interacting condensates provide a new test bed for fundamental atomic and many-body physics. In this thesis we develop a theory that goes beyond the standard mean-field approximation for many-body systems. Feshbach resonances notwithstanding, most experimentally realized atomic-vapor condensates are dilute and are best described by the mean-field Gross-Pitaevskii equation. For this reason, we use dimensional scaling methods to obtain an analytical approximation to the GP equation that is more accurate and flexible than the commonly used ground-state Thomas-Fermi approximation. We also demonstrate the power of dimensional perturbation theory by providing a full solution of a model BEC Hamiltonian and a two-electron quantum dot Hamiltonian. A feature shared by these examples is the high degree of accuracy provided by the lowest orders of the perturbation theory. In our approach to the full many-body BEC Hamiltonian, we use the lowest orders of many-body dimensional perturbation theory to obtain semi-analytical ground-state energies and collective excitation frequencies. Our many-body calculations for BEC's compare well with the Gross-Pitaevskii results in the weakly-interacting regime, as they should, and are much improved over mean-field theory predictions in the strongly-interacting regime.

McKinney, Brett Allen

319

The van der Waals Potential Coefficients ?C60 and ?C61 of the Intercombination Cd Line 326.1 nm for Pure Cd and Cd-Inert Gas Systems  

NASA Astrophysics Data System (ADS)

The absorption profiles of the Cd 326.1 nm line for pure Cd and Cd-inert gases (Xe, Kr, Ar, Ne and He) have been carefully studied from the line center to 700 cm-1 in the red wing using a high resolution double beam spectrometer. The density of Cd was about 5.108×1018 atoms cm-3. The temperature dependences of the red wings of these profiles were analysed in the frame work of the unified Frank Condon (UFC) treatment of pressure broadening of spectral lines developed by Szudy and Baylis. The van der Waals potential coefficient differences ?C60 and ?C61 between the ground 30+ state and the two exited states 30+ and 31 were obtained using Kuhn's law.

Roston, G. D.; Helmi, M. S.

2008-10-01

320

Condensate dark matter stars  

E-print Network

We investigate the structure and stability properties of compact astrophysical objects that may be formed from the Bose-Einstein condensation of dark matter. Once the critical temperature of a boson gas is less than the critical temperature, a Bose-Einstein Condensation process can always take place during the cosmic history of the universe. Therefore we model the dark matter inside the star as a Bose-Einstein condensate. In the condensate dark matter star model, the dark matter equation of state can be described by a polytropic equation of state, with polytropic index equal to one. We derive the basic general relativistic equations describing the equilibrium structure of the condensate dark matter star with spherically symmetric static geometry. The structure equations of the condensate dark matter stars are studied numerically. The critical mass and radius of the dark matter star are given by $M_{crit}\\approx 2(l_a/1fm)^{1/2}(m_{\\chi}/1\\;{\\rm GeV})^{-3/2}M_{\\odot}$ and $R_{crit}\\approx 1.1 \\times 10^6(l_a/1\\;{\\rm fm})^{1/2}(m_{\\chi}/1\\;{\\rm GeV})^{-3/2}$ cm respectively, where $l_a$ and $m_{\\chi}$ are the scattering length and the mass of dark matter particle, respectively.

X. Y. Li; T. Harko; K. S. Cheng

2012-05-14

321

CONDENSATION AND EVAPORATION FOR THERMALLY UNEQUILIBRATED PHASES  

E-print Network

CONDENSATION AND EVAPORATION FOR THERMALLY UNEQUILIBRATED PHASES R. A. Marcus1 , A. V. Fedkin2-K) equation for the rate of condensation of a gas or evaporation of a solid or liquid is used for systems, and apply it to shock wave- induced evaporation and condensation of a chondrule precursor. Theory

Grossman, Lawrence

322

Charged Condensation  

E-print Network

We consider Bose-Einstein condensation of massive electrically charged scalars in a uniform background of charged fermions. We focus on the case when the scalar condensate screens the background charge, while the net charge of the system resides on its boundary surface. A distinctive signature of this substance is that the photon acquires a Lorentz-violating mass in the bulk of the condensate. Due to this mass, the transverse and longitudinal gauge modes propagate with different group velocities. We give qualitative arguments that at high enough densities and low temperatures a charged system of electrons and helium-4 nuclei, if held together by laboratory devices or by force of gravity, can form such a substance. We briefly discuss possible manifestations of the charged condensate in compact astrophysical objects.

Gregory Gabadadze; Rachel A. Rosen

2007-06-15

323

Dark Matter from the Inert Doublet Model  

E-print Network

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

Laura Lopez Honorez

2007-06-01

324

COMPARISON OF LEVELS OF SULFOLANE AND DIISOPROPANOLAMINE IN NATURAL WETLAND VEGETATION EXPOSED TO GAS-CONDENSATE CONTAMINATED GROUND WATER  

Microsoft Academic Search

Groundwater containing the process chemicals sulfolane (tetrahydrothiophene 1,1-dioxide) and diisopropanolamine (DIPA) has contaminated a wetland in the vicinity of a sour-gas natural gas processing facility. Of concern is the extent of which these contaminants are taken up by vegetation and the associated risk to wildlife that may eat the plants. All sampled wetland plants contained detectable levels of sulfolane and

John V. Headley; Leslie C. Dickson; Kerry M. Peru

2002-01-01

325

Two systems developed for purifying inert atmospheres  

NASA Technical Reports Server (NTRS)

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

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

1969-01-01

326

Passive suspensions incorporating inerters for railway vehicles  

Microsoft Academic Search

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

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

2012-01-01

327

The influence of dredging on the biota of the Barents Sea during development of the Stockman condensed gas deposit  

SciTech Connect

This article focuses on the nature of the possible dispersion of sediment during the construction of major natural gas pipelines on the shelf of the Barents Sea and its influence on the survival rate of marine organisms. 8 refs., 3 figs.

Matishov, G.G.; Shparkovskii, I.A.; Nazimov, V.V. [Murmansk Marine Biological Institute (Russian Federation)

1995-11-01

328

Fundamental insights on impact of non-condensible gas evolution from coating pyrolysis and intentional injection on molten-aluminum water explosion onset during direct-chill casting  

SciTech Connect

Explosive interactions between molten aluminum and water are being studied with a focus on fundamentals to determine what causes robust-enough triggers for explosion onset, to determine the extent of protection provided from various coatings and to develop a fundamentally-based simple, cost-effective novel methodology for prevention. The workscope includes experimentation and mathematical modeling of the interactions between molten metals and water at various different coated and uncoated surfaces. Phenomenological issues related to surface wettability, gas generation from coatings, charring of coatings, inertial constraint, melt temperature, water temperature, external shocks are being investigated systematically to gage their relative impact on the triggerability of surface-assisted steam explosions. The steam explosion triggering studies (SETS) facility was designed and constructed as a rapid-turnaround, cost-effective, and safe means to address these phenomenological issues. Data from SETS tests have indicated that, non-condensible gas (NCG) generation during paint pyrolysis plays a predominant role in explosion prevention. This paper describes results of studies on impact of deliberate NCG injection on explosion prevention, via molten melt drops free-falling into water, as well as from tests using the SETS facility for studying entrapment induced explosive boiling. SETS is also being used to obtain information on time-varying and integral amounts of NCGs generated from various paints. Relevant data are presented. Results of investigations, taken together provide compelling evidence on the positive role NCGs play on explosion prevention.

Taleyarkhan, R.P.; Kim, S.H. [Oak Ridge National Lab., TN (United States); Gulec, K. [Oak Ridge Associated Universities, TN (United States)

1998-05-01

329

Dropwise condensation  

PubMed Central

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

Leach, R. N.; Stevens, F.; Langford, S. C.; Dickinson, J. T.

2008-01-01

330

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

Code of Federal Regulations, 2013 CFR

...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...

2013-07-01

331

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

Code of Federal Regulations, 2010 CFR

...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...

2010-07-01

332

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

Code of Federal Regulations, 2012 CFR

...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...

2012-07-01

333

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

Microsoft Academic Search

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

Michail I. Petaev; John A. Wood

1998-01-01

334

Dilution effect with inert gases in direct synthesis of methanol from methane using nonthermal plasma  

Microsoft Academic Search

Direct synthesis of methanol from CH4 and O2 has been experimentally studied using pulsed discharge plasma in a concentric-cylinder-type reactor. The methanol production was enhanced by dilution of source gas with inert gas, such as Ar and He. The methanol production became about 2.5 times larger at the dilution ratio of 2.5, and gradually decreased with increase of the dilution

Mamoru Okumoto; Zhenzhou Su; Shinji Katsura; Akira Mizuno

1999-01-01

335

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

E-print Network

study the so-called canonical ensemble problem. It describes, in some sense, an intermediate situation as com- pared with the microcanonical ensemble and the grand- canonical ensemble. In the microcanonical ensemble, the gas is completely isolated, E...%n0 2nl~nk11 !pn0 ,$ . . . ,nl21, . . . ,nk11, . . . %n0# 1hkl@nl~nk11 !pn0 ,$nk%n0 2~nl11 !nkpn0 ,$ . . . ,nl11, . . . ,nk21, . . . %n0#% 2k ($nk%n0 (k8.0 @~hk811 !~n011 !nk8pn0 ,$nk%n0 2~hk811 !n0~nk811 !pn021,$nk1dk ,k8%n021 1hk8n0~nk811 !pn0...

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

2000-01-01

336

A plagioclase-olivine-spinel-magnetite inclusion from Maralinga (CK): evidence for sequential condensation and solid-gas exchange  

NASA Astrophysics Data System (ADS)

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.

Kurat, Gero; Zinner, Ernst; Brandstätter, Franz

2002-09-01

337

Antimicrobial activity of silica coated silicon nano-tubes (SCSNT) and silica coated silicon nano-particles (SCSNP) synthesized by gas phase condensation.  

PubMed

Silica-coated, silicon nanotubes (SCSNTs) and silica-coated, silicon nanoparticles (SCSNPs) have been synthesized by catalyst-free single-step gas phase condensation using the arc plasma process. Transmission electron microscopy and scanning tunneling microscopy showed that SCSNTs exhibited a wall thickness of less than 1 nm, with an average diameter of 14 nm and a length of several 100 nm. Both nano-structures had a high specific surface area. The present study has demonstrated cheaper, resistance-free and effective antibacterial activity in silica-coated silicon nano-structures, each for two Gram-positive and Gram-negative bacteria. The minimum inhibitory concentration (MIC) was estimated, using the optical densitometric technique, and by determining colony-forming units. The MIC was found to range in the order of micrograms, which is comparable to the reported MIC of metal oxides for these bacteria. SCSNTs were found to be more effective in limiting the growth of multidrug-resistant Staphylococcus aureus over SCSNPs at 10 ?g/ml (IC 50 = 100 ?g/ml). PMID:23494617

Tank, Chiti; Raman, Sujatha; Karan, Sujoy; Gosavi, Suresh; Lalla, Niranjan P; Sathe, Vasant; Berndt, Richard; Gade, W N; Bhoraskar, S V; Mathe, Vikas L

2013-06-01

338

Acid-catalyzed condensed-phase reactions of limonene and terpineol and their impacts on gas-to-particle partitioning in the formation of organic aerosols.  

PubMed

We investigated the condensed-phase reactions of biogenic VOCs with C double bond C bonds (limonene, C(10)H(16), and terpineol, C(10)H(18)O) catalyzed by sulfuric acid by both bulk solution (BS) experiments and gas-particle (GP) experiments using a flow cell reactor. Product analysis by gas chromatography-mass spectrometry (GC-MS) showed that cationic polymerization led to dimeric and trimeric product formation under conditions of relative humidity (RH) <20% (in the GP experiments) and a sulfuric acid concentration of 57.8 wt % (in the BS experiments), while hydration occurred under conditions of RH > 20% (in the GP experiments) and sulfuric acid concentrations of 46.3 wt % or lower (in the BS experiments). Apparent partitioning coefficients (K(p,rxn)) were estimated from the GP experiments by including the reaction products. Only under extremely low RH conditions (RH < 5%) did the values of K(p,rxn) ( approximately 5 x 10(-6) m(3)/microg for limonene and approximately 2 x 10(-5) m(3)/microg for terpineol) substantially exceed the physical partitioning coefficients (K(p) = 6.5 x 10(-8) m(3)/microg for limonene and =2.3 x 10(-6) m(3)/microg for terpineol) derived from the absorptive partitioning theory. At RH higher than 5%, the apparent partitioning coefficients (K(p,rxn)) of both limonene and terpineol were in the same order of magnitude as the K(p) values derived from the absorptive partitioning theory. Compared with other conditions including VOC concentration and degree of neutralization (by ammonium) of acidic particles, RH is a critical parameter that influences both the reaction mechanisms and the uptake ability (K(p,rxn) values) of these processes. The finding suggests that RH needs to be considered when taking the effects of acid-catalyzed reactions into account in estimating organic aerosol formation from C double bond C containing VOCs. PMID:20550185

Li, Yong Jie; Cheong, Gema Y L; Lau, Arthur P S; Chan, Chak K

2010-07-15

339

HST-COS Spectroscopy of the Cooling Flow in Abell 1795 - Evidence for Inefficient Star Formation in Condensing Intracluster Gas  

E-print Network

We present far-UV spectroscopy from the Cosmic Origins Spectrograph on the Hubble Space Telescope of a cool, star-forming filament in the core of Abell 1795. These data, which span 1025A - 1700A, allow for the simultaneous modeling of the young stellar populations and the intermediate-temperature (10^5.5 K) gas in this filament, which is far removed (~30 kpc) from the direct influence of the central AGN. Using a combination of UV absorption line indices and stellar population synthesis modeling, we find evidence for ongoing star formation, with the youngest stars having ages of 7.5 +/- 2.0 Myr and metallicities of 0.4 +/- 0.2 Zsun. The latter is consistent with the local metallicity of the intracluster medium. We detect the O VI (1038) line, measuring a flux of 4.0 +/- 0.9 x 10^-17 erg s^-1 cm^-2. The O VI (1032) line is redshifted such that it is coincident with a strong Galactic H2 absorption feature, and is not detected. The measured O VI (1038) flux corresponds to a cooling rate of 0.85 +/- 0.2 (stat) +/-...

McDonald, Michael; Veilleux, Sylvain; Ehlert, Steven

2014-01-01

340

HST-COS Spectroscopy of the Cooling Flow in A1795—Evidence for Inefficient Star Formation in Condensing Intracluster Gas  

NASA Astrophysics Data System (ADS)

We present far-UV spectroscopy from the Cosmic Origins Spectrograph on the Hubble Space Telescope of a cool, star-forming filament in the core of A1795. These data, which span 1025 Å < ?rest < 1700 Å, allow for the simultaneous modeling of the young stellar populations and the intermediate-temperature (105.5 K) gas in this filament, which is far removed (~30 kpc) from the direct influence of the central active galactic nucleus. Using a combination of UV absorption line indices and stellar population synthesis modeling, we find evidence for ongoing star formation, with the youngest stars having ages of 7.5^{+2.5}_{-2.0} Myr and metallicities of 0.4^{+0.2}_{-0.1} Z ?. The latter is consistent with the local metallicity of the intracluster medium. We detect the O VI ?1038 line, measuring a flux of f O VI, 1038 = 4.0 ± 0.9 × 10-17 erg s-1 cm-2. The O VI ?1032 line is redshifted such that it is coincident with a strong Galactic H2 absorption feature, and is not detected. The measured O VI ?1038 flux corresponds to a cooling rate of 0.85 ± 0.2 (stat) ± 0.15 (sys) M ? yr-1 at ~105.5 K, assuming that the cooling proceeds isochorically, which is consistent with the classical X-ray luminosity-derived cooling rate in the same region. We measure a star formation rate of 0.11 ± 0.02 M ? yr-1 from the UV continuum, suggesting that star formation is proceeding at 13^{+3}_{-2}% efficiency in this filament. We propose that this inefficient star formation represents a significant contribution to the larger-scale cooling flow problem.

McDonald, Michael; Roediger, Joel; Veilleux, Sylvain; Ehlert, Steven

2014-08-01

341

Steam condensation on finned tubes, in the presence of non-condensable gases and aerosols: Influence of impaction, diffusiophoresis and settling on aerosol deposition  

Microsoft Academic Search

This paper presents a mechanistic model to predict the steam condensation on containment finned tube heat exchangers in the presence of non-condensable gases (NC) and aerosols. The total thermal resistance from the bulk gas to the coolant is formulated as a parallel combination of the convective and condensation gas resistances coupled in series to those of condensate layer, the aerosol

J. L. Muñoz-Cobo; J. Peña; L. E. Herranz; A. Pérez-Navarro

2005-01-01

342

40 CFR 65.151 - Condensers used as control devices.  

Code of Federal Regulations, 2010 CFR

...AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONSOLIDATED FEDERAL AIR RULE Closed Vent Systems, Control Devices, and Routing to a Fuel Gas System or a Process § 65.151 Condensers used as control devices. (a) Condenser equipment and...

2010-07-01

343

Condensates from fields of Turkmenistan as motor fuel components  

Microsoft Academic Search

The differences in condensate produced in 14 gas-condensate fields are examined. The first group of condensates have high contents of cyclic hydrocarbons; the second has a high content of pariffinic hydrocarbons. Both the high-cyclic and high-paraffin condensates can serve as feedstocks for the chemical, petrochemical, and biochemical industries. The naphtha cuts obtained form the condensates with end points of 150

B. A. Kuldzhaev; S. R. Sergienko; E. G. Tsibrova

1986-01-01

344

Determination of mercury in organic solvents and gas condensates by ?flow-injection — inductively coupled plasma mass spectrometry using a modified total consumption micronebulizer fitted with single pass spray chamber  

Microsoft Academic Search

A high-throughput flow-injection — inductively coupled plasma mass spectrometry (ICP MS) analytical method was developed for the determination of mercury in gas condensates and carbon-rich solvents. The sample (undiluted or diluted 10-fold) was introduced via a modified total consumption micronebulizer working at a flow rate of 30 ?l min?1 and fitted with a singlepass spray chamber. This low flow rate and

Brice Bouyssiere; Yoana Nuevo Ordóñez; Charles-Philippe Lienemann; Dirk Schaumlöffel; Ryszard ?obi?ski

2006-01-01

345

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

NASA Technical Reports Server (NTRS)

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.

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

1997-01-01

346

Bose-Einstein Condensate strings  

E-print Network

We consider the possible existence of gravitationally bound general relativistic strings consisting of Bose-Einstein Condensate (BEC) matter which is described, in the Newtonian limit, by the zero temperature time-dependent nonlinear Schr{\\"}odinger equation (the Gross-Pitaevskii equation), with repulsive inter-particle interactions. In the Madelung representation of the wave function, the quantum dynamics of the condensate can be formulated in terms of the classical continuity equation and the hydrodynamic Euler equations. In the case of a condensate with quartic nonlinearity, the condensates can be described as a gas with two pressure terms, the interaction pressure, which is proportional to the square of the matter density, and the quantum pressure, which is without any classical analogue though, when the number of particles in the system is high enough, the latter may be neglected. By assuming cylindrical symmetry, we analyze the physical properties of the BEC strings in both the interaction pressure and ...

Harko, Tiberiu

2014-01-01

347

High-Performance Air Cooling Condenser With Liquid-Vapor Separation  

Microsoft Academic Search

In this investigation, an innovative idea was introduced to design a new kind of high-performance air cooling condensers. This kind of condenser functions to automatically separate liquid from gas and makes condensation always occur in droplet and unsteady thin film condensation mode everywhere in the whole condenser, which results in very high average heat transfer coefficient. An introduction is presented

Di Wu; Zhen Wang; Gui Lu; Xiaofeng Peng

2010-01-01

348

Numerical evaluation of contact and hybrid condensers for geothermal power plants  

Microsoft Academic Search

-The transport and partitioning of gases in two contact condensers in use at The Geysers has been modelled numerically. Improvements on these designs have been investigated. Adding a surface type vent condenser between the main condenser and the first stage gas ejectors improves hydrogen sulphide partitioning dramatically. This ''hybrid condenser'' can match the performance of a surface condenser. Adding a

O WERES

1984-01-01

349

Cosmological tachyon condensation  

E-print Network

We consider the prospects for dark matter/energy unification in k-essence type theories. General mappings are established between the k-essence scalar field, the hydrodynamic and braneworld descriptions. We develop an extension of the general relativistic dust model that incorporates the effects of both pressure and the associated acoustic horizon. Applying this to a tachyon model, we show that this inhomogeneous "variable Chaplygin gas" does evolve into a mixed system containing cold dark matter like gravitational condensate in significant quantities. Our methods can be applied to any dark energy model as well as to mixtures of dark energy and traditional dark matter.

Neven Bilic; Gary B. Tupper; Raoul D. Viollier

2008-09-02

350

Fractionation in the solar nebula - Condensation of yttrium and the rare earth elements  

Microsoft Academic Search

The condensation of Y and the rare earth elements (REE) from the solar nebula may be controlled by thermodynamic equilibrium between gas and condensed solids. Highly fractionated REE patterns may result if condensates are removed from the gas before condensation is complete. It is found that the fractionation is not a smooth function of REE ionic radius but varies in

W. V. Boynton

1975-01-01

351

Simple Techniques For Assessing Impacts Of Oil And Gas Operations On Public Lands: A Field Evaluation Of A Photoionization Detector (PID) At A Condensate Release Site, Padre Island National Seashore, Texas  

USGS Publications Warehouse

Simple, cost-effective techniques are needed for land managers to assess the environmental impacts of oil and gas production activities on public lands, so that sites may be prioritized for remediation or for further, more formal assessment. Field-portable instruments provide real-time data and allow the field investigator to extend an assessment beyond simply locating and mapping obvious disturbances. Field investigators can examine sites for the presence of hydrocarbons in the subsurface using a soil auger and a photoionization detector (PID). The PID measures volatile organic compounds (VOC) in soil gases. This allows detection of hydrocarbons in the shallow subsurface near areas of obvious oil-stained soils, oil in pits, or dead vegetation. Remnants of a condensate release occur in sandy soils at a production site on the Padre Island National Seashore in south Texas. Dead vegetation had been observed by National Park Service personnel in the release area several years prior to our visit. The site is located several miles south of the Malaquite Beach Campground. In early 2001, we sampled soil gases for VOCs in the area believed to have received the condensate. Our purpose in this investigation was: 1) to establish what sampling techniques might be effective in sandy soils with a shallow water and contrast them with techniques used in an earlier study; and 2) delineate the probable area of condensate release. Our field results show that sealing the auger hole with a clear, rigid plastic tube capped at the top end and sampling the soil gas through a small hole in the cap increases the soil VOC gas signature, compared to sampling soil gases in the bottom of an open hole. This sealed-tube sampling method increases the contrast between the VOC levels within a contaminated area and adjacent background areas. The tube allows the PID air pump to draw soil gas from the volume of soil surrounding the open hole below the tube in a zone less influenced by atmospheric air. In an open hole, the VOC readings seem to be strongly dependent on the degree of diffusion and advection of soil gas VOCs into the open hole from the surrounding soil, a process that may vary with soil and wind conditions. Making measurements with the sealed hole does take some additional time (4-7 minutes after the hole is augered) compared to the open-hole technique (1-2 minutes). We used the rigid-plastic tube technique to survey for soil gas VOCs across the entire site, less than ? acre. Condensate has impacted at least 0.28 acres. The impacted area may extend northwest of the surveyed area.

Otton, James K.; Zielinski, Robert A.

2001-01-01

352

Mucosal vaccination against tuberculosis using inert bioparticles.  

PubMed

Needle-free, mucosal immunization is a highly desirable strategy for vaccination against many pathogens, especially those entering through the respiratory mucosa, such as Mycobacterium tuberculosis. Unfortunately, mucosal vaccination against tuberculosis (TB) is impeded by a lack of suitable adjuvants and/or delivery platforms that could induce a protective immune response in humans. Here, we report on a novel biotechnological approach for mucosal vaccination against TB that overcomes some of the current limitations. This is achieved by coating protective TB antigens onto the surface of inert bacterial spores, which are then delivered to the respiratory tract. Our data showed that mice immunized nasally with coated spores developed humoral and cellular immune responses and multifunctional T cells and, most importantly, presented significantly reduced bacterial loads in their lungs and spleens following pathogenic challenge. We conclude that this new vaccine delivery platform merits further development as a mucosal vaccine for TB and possibly also other respiratory pathogens. PMID:23959722

Reljic, Rajko; Sibley, Laura; Huang, Jen-Min; Pepponi, Ilaria; Hoppe, Andreas; Hong, Huynh A; Cutting, Simon M

2013-11-01

353

Inert anodes and advanced smelting of aluminum  

SciTech Connect

This report provides a broad assessment of open literature and patents that exist in the area of inert anodes and their related cathode systems and cell designs, technologies that are relevant for the advanced smelting of aluminum. The report also discusses the opportunities, barriers, and issued associated with these technologies from a technical, environmental, and economic viewpoint. It discusses the outlook for the direct retrofit of advanced reduction technologies to existing aluminum smelters, and compares retrofits to ''brown field'' usage and ''green field'' adoption of the technologies. A number of observations and recommendations are offered for consideration concerning further research and development efforts that may be directed toward these advanced technologies. The opportunities are discussed in the context of incremental progress that is being made in conventional Hall-Heroult cell systems.

ASME Technical Working Group on Inert Anode Technologies

1999-07-01

354

Optimizing Steam & Condensate System: A Case Study  

E-print Network

Optimization of Steam & Condensate systems in any process plant results in substantial reduction of purchased energy cost. During periods of natural gas price hikes, this would benefit the plant in controlling their fuel budget significantly...

Venkatesan, V. V.; Norris, C.

2011-01-01

355

Economics favor GTL projects with condensate coproduction  

Microsoft Academic Search

A moderate scale (20,000 b\\/d) gas-to-liquids (GTL) project can have viable economics if condensate revenues are credited to the project. Many reserves contain valuable condensates and other liquids as well as natural gas. Without such coproduction, near-to-medium term economics are challenging. A few projects of this size will pave the way for larger projects that benefit from economies of scale.

Corke

1998-01-01

356

Continuous distributions of specific ventilation recovered from inert gas washout  

NASA Technical Reports Server (NTRS)

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

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

1978-01-01

357

Inert gas test of two 12-cm magnetostatic thrusters  

NASA Technical Reports Server (NTRS)

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

Ramsey, W. D.

1982-01-01

358

INERT-MATRIX FUEL: ACTINIDE ''BURINGIN'' AND DIRECT DISPOSAL  

Microsoft Academic Search

Excess actinides result from the dismantlement of nuclear weapons (Pu) and the reprocessing of commercial spent nuclear fuel (mainly 241 Am, 244 Cm and 237 Np). In Europe, Canada and Japan studies have determined much improved efficiencies for burnup of actinides using inert-matrix fuels. This innovative approach also considers the properties of the inert-matrix fuel as a nuclear waste form

Rodney C. Ewing; Lumin Wang

2002-01-01

359

Electrolytic production of high purity aluminum using ceramic inert anodes  

DOEpatents

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.

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

360

40 CFR 65.151 - Condensers used as control devices.  

...2014-07-01 false Condensers used as control devices. 65.151 Section 65.151...FEDERAL AIR RULE Closed Vent Systems, Control Devices, and Routing to a Fuel Gas System...Process § 65.151 Condensers used as control devices. (a) Condenser...

2014-07-01

361

Process and apparatus for recovering condensable components from fluid streams  

Microsoft Academic Search

A process and apparatus are described for recovering condensable, heavier hydrocarbon components, e.g., propane, butane, etc., from natural gas streams. One of the gas streams originates from a source of gas rich in the hydrocarbon components and at least one of the other gas streams originates from a source of gas lean in the hydrocarbon components. The rich gas is

Humphries

1971-01-01

362

Condensation model for the ESBWR passive condensers  

SciTech Connect

In the General Electric's Economic simplified boiling water reactor (GE-ESBWR) the passive containment cooling system (PCCS) plays a major role in containment pressure control in case of an loss of coolant accident. The PCCS condenser must be able to remove sufficient energy from the reactor containment to prevent containment from exceeding its design pressure following a design basis accident. There are three PCCS condensation modes depending on the containment pressurization due to coolant discharge; complete condensation, cyclic venting and flow through mode. The present work reviews the models and presents model predictive capability along with comparison with existing data from separate effects test. The condensation models in thermal hydraulics code RELAP5 are also assessed to examine its application to various flow modes of condensation. The default model in the code predicts complete condensation well, and basically is Nusselt solution. The UCB model predicts through flow well. None of condensation model in RELAP5 predict complete condensation, cyclic venting, and through flow condensation consistently. New condensation correlations are given that accurately predict all three modes of PCCS condensation. (authors)

Revankar, S. T. [Pohang Univ. of Science and Technology, 400 Central Drive, West Lafayette, IN 47906 (United States); Zhou, W.; Wolf, B.; Oh, S. [Purdue Univ., West Lafayette, IN 47906 (United States)

2012-07-01

363

Bose-Einstein Condensation of Lithium: Observation of Limited Condensate Number  

Microsoft Academic Search

Bose-Einstein condensation of ⁷Li has been studied in a magnetically trapped gas. Because of the effectively attractive interactions between ⁷Li atoms, many-body quantum theory predicts that the occupation number of the condensate is limited to about 1400atoms. We observe the condensate number to be limited to a maximum value between 650 and 1300atoms. The measurements were made using a versatile

C. C. Bradley; C. A. Sackett; R. G. Hulet

1997-01-01

364

Geothermal steam condensate reinjection  

Microsoft Academic Search

Geothermal electric generating plants which use condensing turbines and generate and excess of condensed steam which must be disposed of are discussed. At the Geysers, California, the largest geothermal development in the world, this steam condensate has been reinjected into the steam reservoir since 1968. A total of 3,150,000,000 gallons of steam condensate has been reinjected since that time with

A. J. Chasteen

1974-01-01

365

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

Microsoft Academic Search

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.

W. Ketterle

2000-01-01

366

40 CFR 174.705 - Inert ingredients from sexually compatible plant.  

Code of Federal Regulations, 2013 CFR

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

2013-07-01

367

40 CFR 174.705 - Inert ingredients from sexually compatible plant.  

Code of Federal Regulations, 2012 CFR

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

2012-07-01

368

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

Federal Register 2010, 2011, 2012, 2013

...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...

2010-02-22

369

40 CFR 174.705 - Inert ingredients from sexually compatible plant.  

Code of Federal Regulations, 2011 CFR

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

2011-07-01

370

Electrochemical polishing of hydrogen sulfide from coal synthesis gas  

SciTech Connect

An advanced process has been developed for the separation of H{sub 2}S from coal gasification product streams through an electrochemical membrane. This technology is developed for use in coal gasification facilities providing fuel for cogeneration coal fired electrical power facilities and Molten Carbonate Fuel Cell electrical power facilities. H{sub 2}S is removed from the syn-gas by reduction to the sulfide ion and H at the cathode. The sulfide ion migrates to the anode through a molten salt electrolyte suspended in an inert ceramic matrix. Once at the anode it is oxidized to elemental sulfur and swept away for condensation in an inert gas stream. The syn-gas is enriched with the H{sub 2}. Order-of-magnitude reductions in H{sub 2}S have been repeatably recorded (100 ppm to 10 ppm H{sub 2}S) on a single pass through the cell. This process allows removal of H{sub 2}S without cooling the gas stream and with negligible pressure loss through the separator. Since there are no absorbents used, there is no absorption/regeneration step as with conventional technology. Elemental sulfur is produced as a by-product directly, so there is no need for a Claus process for sulfur recovery. This makes the process economically attractive since it is much less equipment intensive than conventional technology.

Gleason, E.F.; Winnick, J.

1995-11-01

371

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

NASA Technical Reports Server (NTRS)

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

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

1995-01-01

372

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

Microsoft Academic Search

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

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

2011-01-01

373

OPTICAL STUDY OF THE CHARACTERISTICS OF SHOCK-COMPRESSED CONDENSED DIELECTRICS  

Microsoft Academic Search

CONTENTS Introduction 229 I. Study of the optical characteristics of shock-compressed condensed materials, and of the structure and smoothness of the fronts of large-amplitude shock waves 1. Experimental procedure 231 2. Front thickness and smoothness of shock waves in condensed inert and explosive substances 232 3. Density dependence of the refractive index of liquid dielectrics. Anomalous behavior of shock-compressed carbon

S B Kormer

1968-01-01

374

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

NASA Astrophysics Data System (ADS)

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).)

Cornell, Eric A.

1997-04-01

375

Results of experimental studies of the gas-dynamic behavior of airflow in the circulation line of the air condenser of steam-turbine plants  

NASA Astrophysics Data System (ADS)

The results of experimental studies and a physical model of the three-dimensional flow of cooling air in the circulation line (CL) of a dummy air condenser (AC) incorporating a fan, heat-exchange modules, a shell, and other auxiliary components are analyzed. The local air velocity fields determined experimentally at the AC CL inlet and at the fan diffuser outlet are presented. The guidelines for determining the head-capacity characteristics of the airflow through the AC CL are proposed.

Fedorov, V. A.; Mil'man, O. O.; Gribin, V. G.; Anan'ev, P. A.

2014-12-01

376

Condensation system for power plant  

Microsoft Academic Search

A condensation system for use in a power plant including a steam generator and steam turbine comprises at least one side stream condenser. The side stream condenser defines therein first and second hot wells with the first hot well receiving therein condensate produced by condensing steam exhausted from the steam turbine. A condensate pump device forcibly delivers the condensate through

H. Ishimaru; T. Masuda; Y. Nagai

1984-01-01

377

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

SciTech Connect

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.

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

378

Analytical Treatment of Normal Condensation Shock  

NASA Technical Reports Server (NTRS)

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.

Heybey

1947-01-01

379

Analyzing the safety impact of containment inerting at Vermont Yankee  

E-print Network

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

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

1980-01-01

380

Inert electrodes program: Fiscal Year 1987 Annual Report  

SciTech Connect

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

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

1988-12-01

381

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

NASA Technical Reports Server (NTRS)

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.

Chung, Paul M.

1961-01-01

382

Condensation of pure steam and steam-air mixture with surface waves of condensate film on a vertical wall  

Microsoft Academic Search

A series of experiments has been conducted to investigate the effect of wavy interface on film condensation with and without a noncondensable gas present on a vertical wall. Concurrently, the instantaneous film thickness was measured. Overall heat transfer coefficients across the condensate film and the diffusion layer formed by a noncondensable gas were obtained in various parameters such as air-mass

S. K. Park; M. H. Kim; K. J. Yoo

1996-01-01

383

Gas shielding apparatus  

DOEpatents

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.

Brandt, D.

1984-06-05

384

Gas shielding apparatus  

DOEpatents

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.

Brandt, Daniel (Los Alamos, NM)

1985-01-01

385

Gas shielding apparatus  

DOEpatents

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

Brandt, D.

1985-12-31

386

An assessment of PWR steam generator condensation at the Oregon State University APEX facility  

Microsoft Academic Search

This report describes the testing to assess steam generator U-tube steam condensation conducted at the Oregon State University Advanced Plant Experiment Test Facility from 2005 to 2007. Six separate SG condensation (without non-condensable gas) tests were conducted as part of this test program. These tests were designed to evaluate steam condensation rates in a scaled Pressurized Water Reactor steam generator

Brian G. Woods; John Groome; Brian Collins

2009-01-01

387

The partitioning of hydrogen sulfide in the condensers of Geysers Unit 15  

Microsoft Academic Search

Geysers Unit 15 was the first of the geothermal units equipped with surface condensers to go on line at The Geysers power plant of the Pacific Gas and Electric Company. Units 1 through 12 have contact condensers. The switch to surface condensers was motivated by considerations of hydrogen sulfide mission abatement. In the contact condensers, there is a large liquid-to-vapor

O. Weres

1982-01-01

388

Shock compression of condensed matter using multimaterial reactive ghost fluid method  

Microsoft Academic Search

For the flow analysis of reactive compressible media involving energetic materials and deforming metallic boundaries, a HYDRO-SCCM (shock compression of condensed matter) tool is developed for handling multiphysics shock analysis of energetic and inert matters. The highly energetic flows give rise to the strong nonlinear shock waves and the high strain rate deformation of solid boundaries at high pressure and

Ki-Hong Kim; Jack J. Yoh

2008-01-01

389

Condensed Matter Physics  

Microsoft Academic Search

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 \\

Michael P. Marder

2000-01-01

390

Vortices and turbulence in trapped atomic condensates  

PubMed Central

After more than a decade of experiments generating and studying the physics of quantized vortices in atomic gas Bose–Einstein condensates, research is beginning to focus on the roles of vortices in quantum turbulence, as well as other measures of quantum turbulence in atomic condensates. Such research directions have the potential to uncover new insights into quantum turbulence, vortices, and superfluidity and also explore the similarities and differences between quantum and classical turbulence in entirely new settings. Here we present a critical assessment of theoretical and experimental studies in this emerging field of quantum turbulence in atomic condensates. PMID:24704880

White, Angela C.; Anderson, Brian P.; Bagnato, Vanderlei S.

2014-01-01

391

Vortices and turbulence in trapped atomic condensates.  

PubMed

After more than a decade of experiments generating and studying the physics of quantized vortices in atomic gas Bose-Einstein condensates, research is beginning to focus on the roles of vortices in quantum turbulence, as well as other measures of quantum turbulence in atomic condensates. Such research directions have the potential to uncover new insights into quantum turbulence, vortices, and superfluidity and also explore the similarities and differences between quantum and classical turbulence in entirely new settings. Here we present a critical assessment of theoretical and experimental studies in this emerging field of quantum turbulence in atomic condensates. PMID:24704880

White, Angela C; Anderson, Brian P; Bagnato, Vanderlei S

2014-03-25

392

Rydberg excitation of Bose-Einstein condensates  

E-print Network

Rydberg atoms provide a wide range of possibilities to tailor interactions in a quantum gas. Here we report on Rydberg excitation of Bose-Einstein condensed 87Rb atoms. The Rydberg fraction was investigated for various excitation times and temperatures above and below the condensation temperature. The excitation is locally blocked by the van der Waals interaction between Rydberg atoms to a density-dependent limit. Therefore the abrupt change of the thermal atomic density distribution to the characteristic bimodal distribution upon condensation could be observed in the Rydberg fraction. The observed features are reproduced by a simulation based on local collective Rydberg excitations.

Rolf Heidemann; Ulrich Raitzsch; Vera Bendkowsky; Björn Butscher; Robert Löw; Tilman Pfau

2007-10-30

393

Condensation in Microchannels  

Microsoft Academic Search

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

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

2008-01-01

394

Beware of condenser fouling  

Microsoft Academic Search

Many chemical process plants generate steam for power production and process use. Recovering this steam as condensate, and returning it to the boiler, is an economical way to recycle heat. This is usually done in a watercooled, steam-surface condenser located at the exhaust of a turbine. Poor performance of such a condenser -- which is really a large heat exchanger

Buecker

1995-01-01

395

Specific features pertinent to calculation of a condenser with inclined tubes  

NASA Astrophysics Data System (ADS)

Matters concerned with calculation of heat and mass transfer during steam condensation from steam-gas mixtures in a condenser with inclined tubes used in production of sulfate-cellulose for recovering heat and chemical agents are discussed.

Romanova, L. V.; Gogonin, I. I.

2012-08-01

396

"Inert" Strengths of Silicon Nitride Ceramics at Elevated Temperatures  

NASA Technical Reports Server (NTRS)

An attempt to determine high temperature "inert" strengths of several silicon nitride ceramics was made by using dynamic fatigue testing at the very high stressing rate of 2 x 106 MPa/min. The fatigue strengths of all the silicon nitride materials exhibited a well-defined convergence to the corresponding room-temperature inert strengths as stressing rate was increased. The result showed that the high temperature Inert" strength of a ceramic material can be obtained by using sufficiently high stressing rates (greater or = 2 x 10(exp 6) MPa/min) at which fatigue strength converges to a specific value. The specific value can be close to the room-temperature strength of the material.

Choi, Sung R.; Salem, Jonathan A.

1996-01-01

397

Disequilibrium condensation environments in space - A frontier in thermodynamics  

NASA Technical Reports Server (NTRS)

The thermal-disequilibrium aspect of the problem of dust-particle formation from a gas phase in an open space environment is discussed in an effort to draw attention to the space condensation environment as an interesting arena for application and extension of the ideas and formalisms of nonequilibrium thermodynamics. It is shown that quasi-steady states with a disequilibrium between the gas-phase kinetic temperature and the condensed-phase internal temperature appear to be the norm of condensation environments in space. Consideration of the case of condensation onto a bulk condensed phase indicates that these quasi-steady states may constitute Prigogine dissipative structures. It is suggested that a proper study of the process of condensation in a space environment should include any effects arising from thermal disequilibrium.

De, B. R.

1979-01-01

398

Condensation Front Migration in a Protoplanetary Nebula  

NASA Technical Reports Server (NTRS)

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.

Davis, Sanford S.

2004-01-01

399

Potential Condensed Fuel for the Milky Way  

E-print Network

Potential condensed clouds of gas in the Galactic halo are examined in the context of the recent models of cooling, fragmenting clouds building up the baryonic mass of the Galaxy. 582 high-velocity clouds (HVCs) are defined as the potential infalling, condensed clouds and the sample's spatial and velocity distribution are presented. With the majority of the hydrogen in the clouds ionized (~85%), the clouds at a distribution of distances within 150 kpc, and their individual total masses below 10^7 Msun, the total mass in potentially condensed clouds is 1.1 - 1.4 x 10^9 Msun. If the tighter distance constraint of < 60 kpc is adopted this mass range drops to 4.5 - 6.1 x 10^8 Msun. The implications on the condensing cloud models, as well as feedback and additional accretion methods, are discussed.

Putman, M E

2006-01-01

400

Potential Condensed Fuel for the Milky Way  

E-print Network

Potential condensed clouds of gas in the Galactic halo are examined in the context of the recent models of cooling, fragmenting clouds building up the baryonic mass of the Galaxy. 582 high-velocity clouds (HVCs) are defined as the potential infalling, condensed clouds and the sample's spatial and velocity distribution are presented. With the majority of the hydrogen in the clouds ionized (~85%), the clouds at a distribution of distances within 150 kpc, and their individual total masses below 10^7 Msun, the total mass in potentially condensed clouds is 1.1 - 1.4 x 10^9 Msun. If the tighter distance constraint of < 60 kpc is adopted this mass range drops to 4.5 - 6.1 x 10^8 Msun. The implications on the condensing cloud models, as well as feedback and additional accretion methods, are discussed.

M. E. Putman

2006-03-23

401

Bose-Einstein Condensation of Pions  

E-print Network

Particle number fluctuations are studied in the ideal pion gas approaching Bose-Einstein condensation. Two different cases are considered: Bose condensation of pions at large charge densities $\\rho_Q$ and Bose condensation at large total densities of pions $\\rho_{\\pi}$. Calculations are done in grand canonical, canonical and microcanonical ensembles. At high collision energy, in the samples of events with a fixed number of all pions, $N_{\\pi}$, one may observe a prominent signal. When $N_{\\pi}$ increases the scaled variances for particle number fluctuations of both neutral and charged pions increase dramatically in the vicinity of the Bose-Einstein condensation line. As an example, the estimates are presented for $p+p$ collisions at the beam energy of 70 GeV.

Viktor Begun; Mark Gorenstein

2007-09-10

402

Quark Condensates: Flavour Dependence  

E-print Network

We determine the q-bar q condensate for quark masses from zero up to that of the strange quark within a phenomenologically successful modelling of continuum QCD by solving the quark Schwinger-Dyson equation. The existence of multiple solutions to this equation is the key to an accurate and reliable extraction of this condensate using the operator product expansion. We explain why alternative definitions fail to give the physical condensate.

R. Williams; C. S. Fischer; M. R. Pennington

2007-03-23

403

Economical Condensing Turbines?  

E-print Network

Economical Condensing Turbines? by J.E.Dean, P.E. Steam turbines have long been used at utilities and in industry to generate power. There are three basic types of steam turbines: condensing, letdown 1 and extraction/condensing. ? Letdown... turbines reduce the pressure of the incoming steam to one or more pressures and generate power very efficiently, assuming that all the letdown steam has a use. Two caveats: ? Letdown turbines produce power based upon steam requirements and not based upon...

Dean, J. E.

404

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

405

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

NASA Astrophysics Data System (ADS)

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.

Watabe, Shohei; Ohashi, Yoji

2014-07-01

406

Condensation Energy of a Spacetime Condensate  

E-print Network

Starting from an analogy between the Planck-Einstein scale and the dual length scales in Ginzburg-Landau theory of superconductivity, and assuming that space-time is a condensate of neutral fermionic particles with Planck mass, we derive the baryonic mass of the universe. In that theoretical framework baryonic matter appears to be associated with the condensation energy gained by spacetime in the transition from its normal (symetric) to its (less symetric) superconducting-like phase. It is shown however that the critical transition temperature cannot be the Planck temperature. Thus leaving open the enigma of the microscopic description of spacetime at quantum level.

Clovis Jacinto de Matos; Pavol Valko

2010-12-17

407

Rotating trapped Bose-Einstein condensates  

SciTech Connect

After reviewing the ideal Bose-Einstein gas in a box and in a harmonic trap, the effect of interactions on the formation of a Bose-Einstein condensate are discussed, along with the dynamics of small-amplitude perturbations (the Bogoliubov equations). When the condensate rotates with angular velocity {Omega}, one or several vortices nucleate, leading to many observable consequences. With more rapid rotation, the vortices form a dense triangular array, and the collective behavior of these vortices has additional experimental implications. For {Omega} near the radial trap frequency {omega}{sub perpendicular}, the lowest-Landau-level approximation becomes applicable, providing a simple picture of such rapidly rotating condensates. Eventually, as {Omega}{yields}{omega}{sub perpendicular}, the rotating dilute gas is expected to undergo a quantum phase transition from a superfluid to various highly correlated (nonsuperfluid) states analogous to those familiar from the fractional quantum Hall effect for electrons in a strong perpendicular magnetic field.

Fetter, Alexander L. [Geballe Laboratory for Advanced Materials and Departments of Physics and Applied Physics, Stanford University, Stanford, California 94305-4045 (United States)

2009-04-15

408

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

Code of Federal Regulations, 2011 CFR

...uses an inerting or enriching system may not be operated at a vacuum after the injection point unless: (1) There are no sleeve-type pipe couplings, vacuum relief valves, or other devices which could allow air into the vapor collection system...

2011-07-01

409

Inert Electrodes Program fiscal year 1988 annual report  

SciTech Connect

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

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

1989-10-01

410

What are Inert Ingredients?1 Frederick M. Fishel2  

E-print Network

PI-44 What are Inert Ingredients?1 Frederick M. Fishel2 1. This document is PI-44, one of a series. Use pesticides safely. Read and follow directions on the manufacturer's label. The Institute of Food-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status

Watson, Craig A.

411

Porous HMX initiation studies-sugar as an inert simulant  

Microsoft Academic Search

For several years we have been using magnetic particle velocity gauges to study the shock loading of porous HMX (65 and 73% TMD) of different particle sizes to determine their compaction and initiation characteristics. Because it has been difficult to separate the effects of compaction and reaction, an inert simulant was needed with properties similar to HMX. Sugar was selected

S. A. Sheffield; R. L. Gustavsen; R. R. Alcon

1998-01-01

412

Porous HMX initiation studies -- Sugar as an inert simulant  

Microsoft Academic Search

For several years the authors have been using magnetic particle velocity gauges to study the shock loading of porous HMX (65 and 73% TMD) of different particle sizes to determine their compaction and initiation characteristics. Because it has been difficult to separate the effects of compaction and reaction, an inert simulant was needed with properties similar to HMX. Sugar was

S. A. Sheffield; R. L. Gustavsen; R. R. Alcon

1997-01-01

413

Porous HMX initiation studies—sugar as an inert simulant  

Microsoft Academic Search

For several years we have been using magnetic particle velocity gauges to study the shock loading of porous HMX (65 and 73% TMD) of different particle sizes to determine their compaction and initiation characteristics. Because it has been difficult to separate the effects of compaction and reaction, an inert simulant was needed with properties similar to HMX. Sugar was selected

S. A. Sheffield; R. L. Gustavsen; R. R. Alcon

1998-01-01

414

Porous HMX Initiation Studies =96 Sugar as an Inert Simulant  

Microsoft Academic Search

For several years we have been using magnetic particle velocity gauges to study the shock loading of porous HMX (65 and 74% TMD) of different particle sizes to determine their compaction and initiation characteristics. Because it has been difficult to separate the effects of compaction and reaction, an inert simulant was needed with properties similar to HMX. Sugar was selected

S. A. Sheffield; R. L. Gustavsen; R. R. Alcon

1997-01-01

415

Contamination control in semiconductor industry using laminar barrier inerting technology  

Microsoft Academic Search

Laminar Barrier Inerting is a new and effective method of preventing air infiltration into semiconductor process equipment. Air infiltration during loading and unloading is a major source of contamination within semiconductor process furnaces. During these steps, cooler clean room air can replace hot process nitrogen due to buoyant forces. Many fabrication processes are quite sensitive to oxygen and moisture resulting

E. Quilantang; A. Sharif; A. Hosein; T. Yokum; R. Cartwright

1994-01-01

416

Dark Matter with Two Inert Doublets plus One Higgs Doublet  

E-print Network

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.

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

2014-07-29

417

Investigation of the Noncondensable Effect and the Operational Modes of the Passive Condenser System  

SciTech Connect

An experimental study is performed to investigate the effect of noncondensable gas in a passive condenser system. A vertical condenser tube is submerged in a water pool where the heat transferred from the condenser tube is removed through boiling. Data are obtained for three operational modes of the passive condenser. Degradation of the condensation with noncondensable gas is investigated. The condensation heat transfer rate is enhanced by increasing the inlet steam flow rate and the system pressure. For the condenser submerged in a saturated water pool, strong primary pressure dependency is observed. A boundary layer-based condensation model and a simple condensation model with the interfacial friction factor correlation are developed. The model predictions are compared with the pure steam data, and the agreement is satisfactory.

Oh, Seungmin; Revankar, Shripad T. [Purdue University (United States)

2005-10-15

418

Bundle design protects air-cooled condensers from freezing  

Microsoft Academic Search

Air-cooled steam condensers used in turbine exhaust systems are subject to costly freeze damage to finned tubes during the winter. These condensers also are vulnerable to loss of thermal performance in summer. Loss of thermal performance is not due to an increased ambient air temperature; it comes from a degraded heat transfer capability resulting from gas-blanketed tubes. The author discusses

Larinoff

1990-01-01

419

Proceedings: Condenser Technology Conference  

Microsoft Academic Search

Steam surface condenser and associated systems performance strongly affects availability and. heat rate in nuclear and fossil power plants. Thirty-one papers presented at the 1993 conference discuss research results, industry experience, and case histories of condenser problems and solutions. These papers have been cataloged separately elsewhere.

Mussalli

1994-01-01

420

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)

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.

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

2013-08-01

421

Predictive Modeling of Steam Condensation onto Finned Tubes in the Presence of Noncondensable Gases for Passive Safety Reactor Containment Heat Exchangers  

Microsoft Academic Search

A mechanistic model is presented to predict the steam condensation on containment finned tubes in the presence of noncondensables (NCs). The total thermal resistance from bulk gas to coolant is formulated as a parallel combination of the convective and condensation gas resistances coupled in series to those of the condensate layer, the wall, and the coolant.The condensate layer thermal resistance

Jose Luis Munoz-Cobo; Maria Jose Palomo; Luis Enrique Herranz

2001-01-01

422

Condensate-removal device for heat exchangers  

NASA Technical Reports Server (NTRS)

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.

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

1973-01-01

423

Condensation in the primitive solar nebula  

Microsoft Academic Search

The distribution of the major elements between vapor and solid has been calculated for a cooling gas of cosmic composition. The assumption is made that high temperature condensates remain in equilibrium with the vapor, affecting the temperatures of appearance of successively less refractory phases. The model suggests that the major textural features and mineralogical composition of the Ca, Al-rich inclusions

Lawrence Grossman

1972-01-01

424

Comparison of film condensation models in presence of non-condensable gases implemented in a CFD Code  

Microsoft Academic Search

Several film condensation models in presence of non-condensable gases are presented. They have been implemented in a CFD code and compared with experimental data. The aim was to improve the code for simulating the gas mixing process in large containment buildings involving steam. The models based on correlation are more robust and simpler, but they work badly out of their

J. M. Martín-Valdepeñas; M. A. Jiménez; F. Martín-Fuertes; J. A. Fernández. Benítez

2005-01-01

425

Simulating film condensation of steam from steam-gas mixtures with different compositions on the outer surface of vertical tubes used in a heat exchanger  

NASA Astrophysics Data System (ADS)

A mathematical model of heat-and mass transfer processes in surface-type heat exchangers that use mixtures of steam with various noncondensable gases as heat carriers is presented. The results of numerical calculations are compared with experimental data reported in the literature. It is shown that the thermal-physical properties of the noncondensable component in a steam-gas mixture have an essential effect on the distribution of concentrations and temperatures over the heat exchanger length and on the heat flux transferred in it.

Dudnik, N. M.; Garyaev, A. B.

2010-06-01

426

Optimizing Steam and Condensate System: A Case Study  

E-print Network

Optimization of Steam & Condensate systems in any process plant results in substantial reduction in purchased energy cost. During periods of natural gas price hikes, this would benefit the plant in controlling their fuel budget significantly...

Venkatesan, V. V.; Merritt, B.; Tully, R. C.

427

Symmetry classification of spinor Bose-Einstein condensates  

SciTech Connect

We propose a method for systematically finding ground states of spinor Bose-Einstein condensates by utilizing the symmetry properties of the system. By this method, we can find not only an inert state, whose symmetry is maximal in the manifold under consideration, but also a noninert state, which has lower symmetry and depends on the parameters in the Hamiltonian. We establish the symmetry-classification method for the spin-1, 2, and 3 cases at zero magnetic field, and find an additional phase in the last case. The properties of the vortices in the spin-3 system are also discussed.

Kawaguchi, Yuki [Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Ueda, Masahito [Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Macroscopic Quantum Control Project, ERATO, JST, Bunkyo-ku, Tokyo 113-8656 (Japan)

2011-11-15

428

Bose-Einstein condensation of sodium atoms  

NASA Astrophysics Data System (ADS)

Bose-Einstein Condensation in an ultracold gas of neutral sodium atoms has been observed and studied. This was achieved utilizing a combination of laser cooling techniques, magnetic trapping and evaporative cooling. A novel tightly confining dc magnetic trap was developed and demonstrated. This trap combines tight confinement with excellent optical access. Evaporative cooling in this trap produced Bose condensates of 5× 106 atoms, a tenfold improvement over previous results. The Bose-Einstein phase transition was studied and characterized by mapping out the condensed fraction as a function of temperature across the transition point. The characteristic mean-field interaction of particles in the condensate was investigated. Collective excitations of a dilute Bose condensate have been observed. These excitations are analogous to phonons in superfluid helium. The frequencies of the lowest modes were studied for a temperature close to 0 K and compared with theoretical predictions based on mean-field theory. The characteristic damping of one of the modes was measured and compared to damping of 'sound waves' in an ultra-cold gas above the Bose-Einstein transition. We have also demonstrated an output coupler for Bose condensed atoms in a magnetic trap. With short rf pulses Bose condensates were put into a superposition of trapped and untrapped hyperfine states. By varying the rf amplitude we could adjust the fraction of outcoupled atoms between 0 and 100%. This source produces pulses of coherent atoms and can be regarded as a pulsed 'atom laser'. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)

Mewes, Marc-Oliver

1997-10-01

429

Condensed Matter Nuclear Science  

NASA Astrophysics Data System (ADS)

1. General. A tribute to gene Mallove - the "Genie" reactor / K. Wallace and R. Stringham. An update of LENR for ICCF-11 (short course, 10/31/04) / E. Storms. New physical effects in metal deuterides / P. L. Hagelstein ... [et al.]. Reproducibility, controllability, and optimization of LENR experiments / D. J. Nagel -- 2. Experiments. Electrochemistry. Evidence of electromagnetic radiation from Ni-H systems / S. Focardi ... [et al.]. Superwave reality / I. Dardik. Excess heat in electrolysis experiments at energetics technologies / I. Dardik ... [et al.]. "Excess heat" during electrolysis in platinum/K[symbol]CO[symbol]/nickel light water system / J. Tian ... [et al.]. Innovative procedure for the, in situ, measurement of the resistive thermal coefficient of H(D)/Pd during electrolysis; cross-comparison of new elements detected in the Th-Hg-Pd-D(H) electrolytic cells / F. Celani ... [et al.]. Emergence of a high-temperature superconductivity in hydrogen cycled Pd compounds as an evidence for superstoihiometric H/D sites / A. Lipson ... [et al.]. Plasma electrolysis. Calorimetry of energy-efficient glow discharge - apparatus design and calibration / T. B. Benson and T. O. Passell. Generation of heat and products during plasma electrolysis / T. Mizuno ... [et al.]. Glow discharge. Excess heat production in Pd/D during periodic pulse discharge current in various conditions / A. B. Karabut. Beam experiments. Accelerator experiments and theoretical models for the electron screening effect in metallic environments / A. Huke, K. Czerski, and P. Heide. Evidence for a target-material dependence of the neutron-proton branching ratio in d+d reactions for deuteron energies below 20keV / A. Huke ... [et al.]. Experiments on condensed matter nuclear events in Kobe University / T. Minari ... [et al.]. Electron screening constraints for the cold fusion / K. Czerski, P. Heide, and A. Huke. Cavitation. Low mass 1.6 MHz sonofusion reactor / R. Stringham. Particle detection. Research into characteristics of X-ray emission laser beams from solidstate cathode medium of high-current glow discharge / A. B. Karabut. Charged particles from Ti and Pd foils / L. Kowalski ... [et al.]. Cr-39 track detectors in cold fusion experiments: review and perspectives / A. S. Roussetski. Energetic particle shower in the vapor from electrolysis / R. A. Oriani and J. C. Fisher. Nuclear reactions produced in an operating electrolysis cell / R. A. Oriani and J. C. Fisher. Evidence of microscopic ball lightning in cold fusion experiments / E. H. Lewis. Neutron emission from D[symbol] gas in magnetic fields under low temperature / T. Mizuno ... [et al.]. Energetic charged particle emission from hydrogen-loaded Pd and Ti cathodes and its enhancement by He-4 implantation / A. G. Lipson ... [et al.]. H-D permeation. Observation of nuclear transmutation reactions induced by D[symbol] gas permeation through Pd complexes / Y. Iwamura ... [et al.]. Deuterium (hydrogen) flux permeating through palladium and condensed matter nuclear science / Q. M. Wei ... [et al.]. Triggering. Precursors and the fusion reactions in polarized Pd/D-D[symbol]O system: effect of an external electric field / S. Szpak, P. A. Mosier-Boss, and F. E. Gordon. Calorimetric and neutron diagnostics of liquids during laser irradiation / Yu. N. Bazhutov ... [et al.]. Anomalous neutron capture and plastic deformation of Cu and Pd cathodes during electrolysis in a weak thermalized neutron field: evidence of nuclei-lattice exchange / A. G. Lipson and G. H. Miley. H-D loading. An overview of experimental studies on H/Pd over-loading with thin Pd wires and different electrolytic solutions / A. Spallone ... [et al.] -- 3. Transmutations. Photon and particle emission, heat production, and surface transformation in Ni-H system / E. Campari ... [et al.]. Surface analysis of hydrogen-loaded nickel alloys / E. Campari ... [et al.]. Low-energy nuclear reactions and the leptonic monopole / G. Lochak and L. Urutskoev. Results of analysis of Ti foil after glow discharge with deuterium / I. B. Savvat

Biberian, Jean-Paul

2006-02-01

430

Steam condenser performance  

SciTech Connect

To understand condenser performance, it is necessary to perceive it as a whole machine and not just a single tube or tube bundle. A new heat-transfer rate is defined based on overall tube-bundle performance. This condenser performance standard has achieved its intended mission. Overall tube-bundle heat-transfer rates ensure that users can rely on the results in their plant design. It also assures users that they can purchase the performance from competent manufacturers. The paper discusses condenser operation and design, tube bundle operation and design, and heat transfer rate.

NONE

1995-05-01

431

Polariton Condensate Transistor Switch  

E-print Network

A polariton condensate transistor switch is realized through optical excitation of a microcavity ridge with two beams. The ballistically ejected polaritons from a condensate formed at the source are gated using the 20 times weaker second beam to switch on and off the flux of polaritons. In the absence of the gate beam the small built-in detuning creates potential landscape in which ejected polaritons are channelled toward the end of the ridge where they condense. The low loss photon-like propagation combined with strong nonlinearities associated with their excitonic component makes polariton based transistors particularly attractive for the implementation of all-optical integrated circuits.

Gao, T; Liew, T C H; Tsintzos, S I; Stavrinidis, G; Deligeorgis, G; Hatzopoulos, Z; Savvidis, P G

2012-01-01

432

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

PubMed

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

Chandrasekaran, Sriraam R; Hopke, Philip K

2012-12-01

433

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

NASA Astrophysics Data System (ADS)

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.

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

2011-06-01

434

Continuous droplet removal upon dropwise condensation of humid air on a hydrophobic micropatterned surface.  

PubMed

Combination of two physical phenomena, capillary pressure gradient and wettability gradient, allows a simple two-step fabrication process that yields a reliable hydrophobic self-cleaning condenser surface. The surface is fabricated with specific microscopic topography and further treatment with a chemically inert low-surface-energy material. This process does not require growth of nanofeatures (nanotubes) or hydrophilic-hydrophobic patterning of the surface. Trapezoidal geometry of the microfeatures facilitates droplet transfer from the Wenzel to the Cassie state and reduces droplet critical diameter. The geometry of the micropatterns enhances local coalescence and directional movement for droplets with diameter much smaller than the radial length of the micropatterns. The hydrophobic self-cleaning micropatterned condenser surface prevents liquid film formation and promotes continuous dropwise condensation cycle. Upon dropwise condensation, droplets follow a designed wettability gradient created with micropatterns from the most hydrophobic to the least hydrophobic end of the surface. The surface has higher condensation efficiency, due to its directional self-cleaning property, than a plain hydrophobic surface. We explain the self-actuated droplet collection mechanism on the condenser surface and demonstrate experimentally the creation of an effective wettability gradient over a 6 mm radial distance. In spite of its fabrication simplicity, the fabricated surface demonstrates self-cleaning property, enhanced condensation performance, and reliability over time. Our work enables creation of a hydrophobic condenser surface with the directional self-cleaning property that can be used for collection of biological (chemical, environmental) aerosol samples or for condensation enhancement. PMID:25073014

Zamuruyev, Konstantin O; Bardaweel, Hamzeh K; Carron, Christopher J; Kenyon, Nicholas J; Brand, Oliver; Delplanque, Jean-Pierre; Davis, Cristina E

2014-08-26

435

Influence of the sputtering gas on the preferred orientation of nanocrystalline titanium nitride thin films  

Microsoft Academic Search

Nanocrystalline titanium nitride thin films have been deposited by high pressure reactive magnetron sputtering from an elemental titanium target using a mixture of an inert gas and nitrogen. The mean crystallite or grain size in these films is in the range 8–12 nm as measured from X-ray line broadening. Interestingly, the type of inert gas used in the sputtering gas

Rajarshi Banerjee; Ramesh Chandra; Pushan Ayyub

2002-01-01

436

Bose-Einstein condensation on quantum graphs  

E-print Network

We present results on Bose-Einstein condensation (BEC) on general compact quantum graphs, i.e., one-dimensional systems with a (potentially) complex topology. We first investigate non-interacting many-particle systems and provide a complete classification of systems that exhibit condensation. We then consider models with interactions that consist of a singular part as well as a hardcore part. In this way we obtain generalisations of the Tonks-Girardeau gas to graphs. For this we find an absence of phase transitions which then indicates an absence of BEC.

Jens Bolte; Joachim Kerner

2014-03-02

437

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

DOEpatents

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.

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

438

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

SciTech Connect

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 C lowers corrosion on the inert anode constituents.

Dawless, R.K.; Ray, S.P.; Hosler, R.B.; Kozarek, R.L.; LaCamera, A.F.

2000-02-29

439

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

Federal Register 2010, 2011, 2012, 2013

...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...

2010-01-05

440

Evolution of weak disturbances in inert binary mixtures  

NASA Technical Reports Server (NTRS)

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.

Rasmussen, M. L.

1977-01-01

441

Inert supports for lactic acid fermentation —a technological assessment  

Microsoft Academic Search

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

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

1992-01-01

442

Ghost condensate busting  

SciTech Connect

Applying the Thomas-Fermi approximation to renormalizable field theories, we construct ghost condensation models that are free of the instabilities associated with violations of the null-energy condition.

Bilic, Neven [Rudjer Boskovic Institute, 10002 Zagreb (Croatia)] [Rudjer Boskovic Institute, 10002 Zagreb (Croatia); Tupper, Gary B; Viollier, Raoul D, E-mail: bilic@thphys.irb.hr, E-mail: gary.tupper@uct.ac.za, E-mail: raoul.viollier@uct.ac.za [Centre of Theoretical Physics and Astrophysics, University of Cape Town, Rondebosch 7701 (South Africa)

2008-09-15

443

THE COLOR GLASS CONDENSATE.  

SciTech Connect

The Color Glass Condensate is a state of high density gluonic matter which controls the high energy limit of hadronic interactions. Its properties are important for the initial conditions for matter produced at RHIC.

MCLERRAN,L.

2001-08-26

444

Key condenser failure mechanisms  

SciTech Connect

Eight practical lessons highlight many of the factors that can influence condenser tube corrosion at coal-fired utilities and the effects contaminant in-leakage can have on steam generating units. 1 ref., 4 figs.

Buecker, B.

2009-04-15

445

Ghost Condensate Busting  

E-print Network

Applying the Thomas-Fermi approximation to renormalizable field theories, we construct ghost condensation models that are free of the instabilities associated with violations of the null-energy condition.

Neven Bili?; Gary B. Tupper; Raoul D. Viollier

2008-01-25

446

A new viable region of the inert doublet model  

SciTech Connect

The inert doublet model, a minimal extension of the Standard Model by a second Higgs doublet, is one of the simplest and most attractive scenarios that can explain the dark matter. In this paper, we demonstrate the existence of a new viable region of the inert doublet model featuring dark matter masses between M{sub W} and about 160 GeV. Along this previously overlooked region of the parameter space, the correct relic density is obtained thanks to cancellations between different diagrams contributing to dark matter annihilation into gauge bosons (W{sup +}W{sup ?} and Z{sup 0}Z{sup 0}). First, we explain how these cancellations come about and show several examples illustrating the effect of the parameters of the model on the cancellations themselves and on the predicted relic density. Then, we perform a full scan of the new viable region and analyze it in detail by projecting it onto several two-dimensional planes. Finally, the prospects for the direct and the indirect detection of inert Higgs dark matter within this new viable region are studied. We find that present direct detection bounds already rule out a fraction of the new parameter space and that future direct detection experiments, such as Xenon100, will easily probe the remaining part in its entirety.

Honorez, Laura Lopez [Service de Physique Théorique, Université Libre de Bruxelles, 1050 Brussels (Belgium); Yaguna, Carlos E., E-mail: carlos.yaguna@uam.es, E-mail: llopezho@ulb.ac.be [Departamento de Física Teórica C-XI and Instituto de Física Teórica UAM-CSIC, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid (Spain)

2011-01-01

447

Measure Guideline: Evaporative Condensers  

SciTech Connect

The purpose of this measure guideline on evaporative condensers is to provide information on a cost-effective solution for energy and demand savings in homes with cooling loads. This is a prescriptive approach that outlines selection criteria, design and installation procedures, and operation and maintenance best practices. This document has been prepared to provide a process for properly designing, installing, and maintaining evaporative condenser systems as well as understanding the benefits, costs, and tradeoffs.

German, A.; Dakin, B.; Hoeschele, M.

2012-03-01

448

Development of a standard bench-scale cell for electrochemical studies on inert anodes. Inert Anode/Cathode Program  

SciTech Connect

Objective of this work was to develop a standard bench-scale cell for performing short-term ac and dc polarization studies on inert anode candidate materials in molten cryolite. Two designs for electrochemical cells were developed and successfully evaluated in short-term experiments. Both cells consisted on the inert anode as a small cylindrical specimen partially sheathed in alumina, an Al/Al/sub 2/O/sub 3/ reference electrode, and a cryolite bath saturated in alumina. The difference between the two cells was in the design of the cathode. One cell used a bare solid metal cathode; the other used an aluminum pad similar to the Hall-Heroult configuration.

Windisch, C.F. Jr.; Boget, D.I.

1986-07-01

449

Gas stream purifier  

NASA Technical Reports Server (NTRS)

A gas stream purifier has been developed that is capable of removing corrosive acid, base, solvent, organic, inorganic, and water vapors as well as particulates from an inert mixed gas stream using only solid scrubbing agents. This small, lightweight purifier has demonstrated the ability to remove contaminants from an inert gas stream with a greater than 99 percent removal efficiency. The Gas Stream Purifier has outstanding market and sales potential in manufacturing, laboratory and science industries, medical, automotive, or any commercial industry where pollution, contamination, or gas stream purification is a concern. The purifier was developed under NASA contract NAS9-18200 Schedule A for use in the international Space Station. A patent application for the Gas Stream Purifier is currently on file with the United States Patent and Trademark Office.

Adam, Steven J.

1994-01-01

450

Open Problems in $?$ Particle Condensation  

E-print Network

$\\alpha$ particle condensation is a novel state in nuclear systems. We briefly review the present status on the study of $\\alpha$ particle condensation and address the open problems in this research field: $\\alpha$ particle condensation in heavier systems other than the Hoyle state, linear chain and $\\alpha$ particle rings, Hoyle-analogue states with extra neutrons, $\\alpha$ particle condensation related to astrophysics, etc.

Y. Funaki; M. Girod; H. Horiuchi; G. Roepke; P. Schuck; A. Tohsaki; T. Yamada

2010-03-05

451

Two Heat-Transfer Improvements for Gas Liquefiers  

NASA Technical Reports Server (NTRS)

Two improvements in heat-transfer design have been investigated with a view toward increasing the efficiency of refrigerators used to liquefy gases. The improvements could contribute to the development of relatively inexpensive, portable oxygen liquefiers for medical use. A description of the heat-transfer problem in a pulse-tube refrigerator is prerequisite to a meaningful description of the first improvement. In a pulse-tube refrigerator in particular, one of in-line configuration heat must be rejected from two locations: an aftercooler (where most of the heat is rejected) and a warm heat exchanger (where a small fraction of the total input power must be rejected as heat). Rejection of heat from the warm heat exchanger can be problematic because this heat exchanger is usually inside a vacuum vessel. When an acoustic-inertance tube is used to provide a phase shift needed in the pulse-tube cooling cycle, another problem arises: Inasmuch as the acoustic power in the acoustic-inertance tube is dissipated over the entire length of the tube, the gas in the tube must be warmer than the warm heat exchanger in order to reject heat at the warm heat exchanger. This is disadvantageous because the increase in viscosity with temperature causes an undesired increase in dissipation of acoustic energy and an undesired decrease in the achievable phase shift. Consequently, the overall performance of the pulse-tube refrigerator decreases with increasing temperature in the acoustic-inertance tube. In the first improvement, the acoustic-inertance tube is made to serve as the warm heat exchanger and to operate in an approximately isothermal condition at a lower temperature, thereby increasing the achievable phase shift and the overall performance of the refrigerator. This is accomplished by placing the acoustic-inertance tube inside another tube and pumping a cooling fluid (e.g., water) in the annular space between the tubes. Another benefit of this improvement is added flexibility of design to locate the warm heat-rejection components outside the vacuum vessel. The second improvement is the development of a compact radial-flow condenser characterized by a very high heat transfer coefficient and a small pressure drop.

Martin, Jerry L.

2005-01-01

452

Thermal annealing: a facile way of conferring responsivity to inert alkyl-chain-passivated nanoparticle arrays.  

PubMed

This work demonstrates a facile post-treatment strategy, vacuum thermal annealing, to fabricate a dodecanethiol-passivated gold nanoparticle (Au NP) array with organic solvent sensitivity. Through investigating the structure change of the Au NP array, it was found that the interparticle distance decreased during vacuum heat treatment, which meant a closer arrangement of the particles and a more dense packing of the dodecanethiol ligands in the interparticle region. The condensation would increase the interaction of the alkyl chain and enhance their interdigitation. Furthermore, on the basis of the stretching of the alkyl chains in organic solvents, the thermally treated Au NP array showed a good response to organic solvent or vapor by using the interdigitated dodecanethiol network as its responsive unit. The alkyl chains stretch to different extents in different organic solvents, leading to differences in interparticle distance, which provided a distinct blue shift of maximum wavelength upon exposure to various organic solvents or vapors. All of these results indicated that thermal annealing was an efficient way to confer responsivity to inert Au NP arrays. Together with the cost-effectiveness of such NP arrays, this study has potential in the development of economical sensors for medical diagnostics, food safety screening, and environmental pollution monitoring. PMID:25313464

Zhou, Jun; Song, Guoshuai; Li, Yan; Song, Youxin; Chen, Bin; Zhang, Xuemin; Wang, Tieqiang; Fu, Yu; Li, Fei

2014-11-01

453

Gas mixtures for spark gap closing switches  

DOEpatents

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.

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

1987-02-20

454

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

SciTech Connect

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.

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

455

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

NASA Technical Reports Server (NTRS)

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

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

2001-01-01

456

Laser Isotope Separation Employing Condensation Repression  

SciTech Connect

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.

Eerkens, Jeff W.; Miller, William H.

2004-09-15

457

Infrared applications for steam turbine condenser systems  

NASA Astrophysics Data System (ADS)

Infrared inspection of the main steam condensers at the Peach Bottom Atomic Power Station has been utilized successfully in detecting condenser air in-leakage problems. Air in-leakage lowers the condenser's vacuum, thus decreasing the condenser's efficiency. This creates backpressure on the turbine which lowers its efficiency, resulting in fewer megawatts generated. Air in-leakage also creates an increase in off-gas flow which is a radiological concern for both the plant and the public. Inspections are normally performed on the condenser's manway covers and rupture disks prior to an outage during coast down and post outage. The optimum conditions are 100% power and temperature, however, a high radiation field prevents the inspection until reactor power is down to 65% or less. Anomalies are typically indicated by cooling in the effected areas of the air in-leakage. The anomalies are not limited to air in-leakage. Intermittent water out-leakage, due to a heater dump valve cycling, has been detected when visual inspections field nothing.

Lanius, Mark A.

2000-03-01

458

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

Microsoft Academic Search

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

M. Suban

2000-01-01

459

In-stack condensible particulate matter measurements and issues.  

PubMed

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 em