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1

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

PubMed

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

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

2002-10-01

2

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

Microsoft Academic Search

In this study the mutual influence of heat and mass transfer during gas absorption and evaporation or condensation on the surface of a stagnant droplet in the presence of inert admixtures containing noncon- densable soluble gas is investigated numerically. The performed analysis is pertinent to slow droplet evapo- ration or condensation. The system of transient conjugate nonlinear energy and mass

T. Elperin; A. Fominykh; B. Krasovitov

2007-01-01

3

Microhardness of nanocrystalline palladium and copper produced by inert-gas condensation  

Microsoft Academic Search

This report describes the major results of a Vickers microhardness study of nanocrystalline palladium and copper produced by the inert-gas condensation method. Small grain size is known to have a strong influence on mechanical properties at low and intermediate temperatures, as observed in the Hall--Petch effect, Coble creep, and superplasticity. Until recently, the mechanical properties of nanocrystalline materials with mean

G. W. Nieman; J. R. Weertman; R. W. Siegel

1989-01-01

4

Iron and Cobalt-based magnetic fluids produced by inert gas condensation  

NASA Astrophysics Data System (ADS)

Iron and cobalt nanoparticle fluids have been prepared by inert-gas condensation into an oil/surfactant mixture. Superparamagnetic iron fluids (mean particle size=11.6±0.4 nm) and ferromagnetic cobalt fluids (mean particle size=51.6±3.4 nm) produced by this technique are promising candidates for magnetic targeting and hyperthermia applications.

Hai, Nguyen H.; Lemoine, Raymond; Remboldt, Shaina; Strand, Michelle; Shield, Jeffrey E.; Schmitter, David; Kraus, Robert H.; Michelle Espy, Jr.; Leslie-Pelecky, Diandra L.

2005-05-01

5

Effect of variables in inert gas condensation processing on nanoparticle trajectory simulated by finite volume method.  

PubMed

The finite volume method was applied to the determination of the three-dimensional convection current during inert gas condensation (IGC) processing by using the commercially available software, "Fluent". The lower velocity of the convection current at higher evaporation temperature resulted from the lower value of the coefficient of thermal expansion. The velocity of the convection current increased with increasing chamber pressure, because the driving force of the buoyancy was directly proportional to the gas density. 13% and 17.3% of the particles were trapped during the first period of circulation in the case of the single and double heaters, respectively. PMID:17252783

Lee, Kwang-Min; Juhng, Woo-Nam; Choi, Bo-Young

2006-11-01

6

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

SciTech Connect

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

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

2012-03-06

7

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

SciTech Connect

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

Golkar, Farhad [Mechanical and Materials Engineering, University of Nebraska, Lincoln, Nebraska 68588 (United States); Kramer, M. J.; Zhang, Y.; McCallum, R. W. [Ames Laboratory, Ames, Iowa 50011 (United States); Skomski, R.; Sellmyer, D. J. [Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588 (United States); Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, Nebraska 68588 (United States); Shield, J. E. [Mechanical and Materials Engineering, University of Nebraska, Lincoln, Nebraska 68588 (United States); Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, Nebraska 68588 (United States)

2012-04-01

8

Prevention of fog in the condensation of vapour from mixtures with inert gas, by a regenerative thermal process  

Microsoft Academic Search

In processing, vapours often have to be separated from mixtures mainly containing inert gas, as for example in the cleaning of exhaust air and the recovery of pollutant solvent vapours (volatile organic compounds, VOC). Whenever possible, condensation is applied for this task, since it is thermodynamically the most energy-efficient process. It can be carried out successfully, provided that the vapour

Stephan Kaufmann; Karl Hilfiker

1999-01-01

9

Synthesis and mechanical\\/magnetic properties of nano-grained iron-oxides prepared with an inert gas condensation and pulse electric current sintering process  

Microsoft Academic Search

Nanocrystalline iron-oxide powder was fabricated with an inert gas condensation (IGC) method combined with evaporation, and\\u000a in-situ oxidation techniques. The particle size of iron-oxide powder was controlled by varying the helium gas pressure between\\u000a 0.1 and 10 Torr, with the smallest one =10 nm at 0.1 Torr. The nanostructure was characterized by TEM. Nanocrystalline iron-oxide\\u000a powder was sintered with the

Yong-Ho Choa; Tatachika Nakayama; Tohru Sekino; Koichi Niihara

1999-01-01

10

Enhanced-recovery inert gas processes compared  

Microsoft Academic Search

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

1978-01-01

11

46 CFR 154.904 - Inert gas system: Controls.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 false Inert gas system: Controls. 154.904 Section 154.904...Construction and Equipment Atmospheric Control in Cargo Containment Systems § 154.904 Inert gas system: Controls. The inert gas system must...

2011-10-01

12

SP-100 inert gas act activation  

SciTech Connect

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

Wilcox, A.D.

1991-09-01

13

Humble recovers attic oil with unique inert gas system  

Microsoft Academic Search

Humble Oil and Refining Co. has successfully used inert gas for 4 yr on a high-pressure attic oil recovery project in S. Louisiana. As a result of this extensive injection test, Humble found that noncorrosive inert gas can be obtained from a combined stream of gas compressor engine exhaust and inert generator gas. The resulting gas can be compressed and

Godbold

1965-01-01

14

46 CFR 147.66 - Inert gas fire extinguishing systems.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Inert gas fire extinguishing systems. 147.66 Section...Requirements for Particular Materials § 147.66 Inert gas fire extinguishing systems. (a) Inert gas cylinders forming part of a clean agent...

2012-10-01

15

46 CFR 154.904 - Inert gas system: Controls.  

Code of Federal Regulations, 2012 CFR

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

2012-10-01

16

46 CFR 154.910 - Inert gas piping: Location.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Inert gas piping: Location. 154.910 Section...SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment...Containment Systems § 154.910 Inert gas piping: Location. Inert gas...

2011-10-01

17

46 CFR 154.910 - Inert gas piping: Location.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Inert gas piping: Location. 154.910 Section...SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment...Containment Systems § 154.910 Inert gas piping: Location. Inert gas...

2012-10-01

18

MUNICIPAL LANDFILL GAS CONDENSATE  

EPA Science Inventory

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

19

46 CFR 153.501 - Requirement for dry inert gas.  

Code of Federal Regulations, 2012 CFR

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

2012-10-01

20

46 CFR 153.501 - Requirement for dry inert gas.  

Code of Federal Regulations, 2011 CFR

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

2011-10-01

21

Inert Gas Generation Utilizing Diesel Exhaust  

SciTech Connect

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

Osgerby, I. T.; Durilla, M.

1981-01-01

22

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

Microsoft Academic Search

Cytogenetic damage was studied in lymphocytes from 23 welders using the Tungsten Inert Gas (TIG), and 21 welders using the Metal Inert Gas (MIG) and\\/ or Metal Active Gas (MAG) methods on stainless steel (SS). A matched reference group I, and a larger reference group II of 94 subjects studied during the same time period, was established for comparison. Whole

Øyvind Jelmert; Inger-Lise Hansteen; Sverre Langård

1995-01-01

23

46 CFR 154.906 - Inert gas generators.  

Code of Federal Regulations, 2011 CFR

...Produce an inert gas containing less than 5% oxygen by volume; (b) Have a device to...sample the discharge of the generator for oxygen content; and (c) Have an audible...when the inert gas contains 5% or more oxygen by...

2011-10-01

24

46 CFR 154.906 - Inert gas generators.  

Code of Federal Regulations, 2012 CFR

...Produce an inert gas containing less than 5% oxygen by volume; (b) Have a device to...sample the discharge of the generator for oxygen content; and (c) Have an audible...when the inert gas contains 5% or more oxygen by...

2012-10-01

25

CMI (Central Mining Institute) Inert Gas Mine Firefighting System.  

National Technical Information Service (NTIS)

The use of inert gas systems to extinguish mine fires has been the subject of research for some time in the United States. In some European countries, it is an established practice. Tests were conducted with the Central Mining Institute (CMI) Inert Gas Sy...

M. Paczkowski G. A. Tracey A. Wojtyczka

1982-01-01

26

46 CFR 153.500 - Inert gas systems.  

Code of Federal Regulations, 2010 CFR

...OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Special Requirements...system that: (a) Maintains the vapor space of the containment system in an inert state by filling the vapor space with a gas that is neither reactive...

2010-10-01

27

46 CFR 153.500 - Inert gas systems.  

Code of Federal Regulations, 2010 CFR

...OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Special Requirements...system that: (a) Maintains the vapor space of the containment system in an inert state by filling the vapor space with a gas that is neither reactive...

2009-10-01

28

Effect of Inert Gas on Turbulent Burning Velocities  

NASA Astrophysics Data System (ADS)

In our previous works, the preferential diffusion effect was found to play an important role in premixed turbulent combustion characteristics, where nitrogen was added as an inert gas to several fuel/oxygen mixtures. In this study, the inert gas is changed to Ar, He and CO2, and the relationship between the turbulent burning velocity and the diffusion coefficient of each inert gas in the multi-component mixture is examined experimentally. As a result, Ar and CO2 added mixtures show slightly larger turbulent burning velocities than that of nitrogen added mixtures. On the contrary, He added mixtures show very smaller turbulent burning velocities at the same equivalence ratio. These characteristics are discussed in connection with each diffusion coefficient of fuel, oxygen and inert gas in multi-component system.

Kido, Hiroyuki; Hashimoto, Jun; Barat, Dilmurat; Nishigaki, Masashi; Okamoto, Hideki

29

46 CFR 154.903 - Inert gas systems: General.  

Code of Federal Regulations, 2011 CFR

...carry and the materials of construction of the cargo tanks, hold and interbarrier spaces, and insulation. (b) The boiling point and dewpoint at atmospheric pressure of the inert gas must be below the temperature of any surface in those spaces...

2011-10-01

30

46 CFR 154.903 - Inert gas systems: General.  

Code of Federal Regulations, 2012 CFR

...carry and the materials of construction of the cargo tanks, hold and interbarrier spaces, and insulation. (b) The boiling point and dewpoint at atmospheric pressure of the inert gas must be below the temperature of any surface in those spaces...

2012-10-01

31

46 CFR 154.908 - Inert gas generator: Location.  

Code of Federal Regulations, 2011 CFR

...Design, Construction and Equipment Atmospheric Control in Cargo Containment Systems § 154.908...not in the cargo area and does not have direct access to any accommodation, service, or control space. (b) An inert gas generator...

2011-10-01

32

46 CFR 154.908 - Inert gas generator: Location.  

Code of Federal Regulations, 2012 CFR

...Design, Construction and Equipment Atmospheric Control in Cargo Containment Systems § 154.908...not in the cargo area and does not have direct access to any accommodation, service, or control space. (b) An inert gas generator...

2012-10-01

33

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

34

Cooling gas from condensed gas deposits  

Microsoft Academic Search

The gas from a well in a condensed gas deposit contains condensate and water, which must be separated from the gas, since otherwise they form crystalline hydrates that block the pipelines and equipment. Moreover, the condensate is a very valuable raw material used in industry [1]. It must be separated either by adsorption (with the aid of some adsorber) or

V. P. Yablonskaya

1965-01-01

35

46 CFR 153.500 - Inert gas systems.  

Code of Federal Regulations, 2011 CFR

...LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS...from raising the cargo tank pressure to more than...discharge; (c) Has storage for enough inerting gas...normally lost while the tank's atmosphere is maintained...condition (e.g. through tank breathing and...

2011-10-01

36

46 CFR 153.500 - Inert gas systems.  

Code of Federal Regulations, 2012 CFR

...LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS...from raising the cargo tank pressure to more than...discharge; (c) Has storage for enough inerting gas...normally lost while the tank's atmosphere is maintained...condition (e.g. through tank breathing and...

2012-10-01

37

Flammability of gas mixtures. Part 2: influence of inert gases.  

PubMed

Ternary systems, which contain flammable gas, inert gas and air, were studied in order to give the user an evaluation of the ISO 10156 calculation method for the flammability of gas mixtures. While in Part 1 of this article the fire potential of flammable gases was the focal point, the influence of inert gases on the flammability of gas mixtures was studied in Part 2. The inerting capacity of an inert gas is expressed by the dimensionless K value, the so-called "coefficient of nitrogen equivalency". The experimental determination of K values is demonstrated by using explosion diagrams. The objective of this study was to compare the estimated results, given by ISO 10156, with measurements of explosion ranges based on the German standard DIN 51649-1, given by CERN and CHEMSAFE. The comparison shows that ISO 10156, Table 1, supplies conservative K values, which can be regarded as safe in all cases. Nevertheless, in a number of cases ISO underestimates the inerting capacity, so that non-flammable gas mixtures are considered flammable. PMID:15885405

Molnarne, Maria; Mizsey, Péter; Schröder, Volkmar

2005-05-20

38

Behaviour of inert gas bubbles under chemical concentration gradients  

Microsoft Academic Search

The paper reports on the growth of helium inert gas bubbles in the copper side of the Cu?Ni diffusion couple. A bimodal distribution of the gas bubbles is created through the effect of the surface in the near surface region and diffusion generated excess vacancies in the diffusion zone. The analysis of the results shows that the presence of a

G. P. Tiwari

1996-01-01

39

Gas condensates as diesel fuel  

Microsoft Academic Search

The data of Table 1 show that the distillation curve of the gas condensate from the Yangi-Kazgan field matches that of A-72 gasoline; the Gazli condensate corresponds to light TS-I jet fuel; the Urtabulak, Gazli-Neft', and Urengoi condensates correspond to wide-cut jet fuel; the Kultak, Zevardy, l~barek, and Shurtan condensates correspond to wide-cut engine fuel. It will be noted that

A. A. Kukushkin; V. S. Azev; G. N. Gerasimova; V. M. Aprelenko; A. I. Kirsanov

1985-01-01

40

Fuzzy pattern recognition of tungsten inert gas weld quality  

Microsoft Academic Search

In this paper, a fuzzy pattern recognition technique is applied to classifying aluminium weld quality in tungsten inert gas (TIG) welding. The pattern vector includes three components, that is, the front height, the back height, and the front width of weld. Based on the values of the pattern vector, good, fair, and poor weld qualities can be automatically classified by

Y. S. Tarng; S. S. Yeh; S. C. Juang

1997-01-01

41

INERT-GAS-SHIELDED CONSUMABLE-ELECTRODE WELDING OF MOLYBDENUM  

Microsoft Academic Search

As part of an over-all program to improve the ductility of molybdenum ; weldments, studies were imitiated to adapt the inert-gas-shielded consumable-; electcode arc-welding process to molybdenum. This paper covers the work required ; to improve metal transfer and arc stabiliiy in molyhdenum arcs before starting ; complete evaluation of this welding process. Arc stability and metal transfer ; could

N. E. Weare; R. E. Monroe; D. C. Martin

1958-01-01

42

Visual\\/vestibular effects of inert gas narcosis  

Microsoft Academic Search

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

M.-F. LALIBERTE; R. HESLEGRAVE; S. KHAN

1993-01-01

43

Sampling gas-condensate wells  

SciTech Connect

The industry has a procedure for stabilizing and sampling retrograde-gas (gas-condensate) wells; however, no investigation of the quality of the samples resulting from this procedure has been published. During sampling, bottomhole flowing pressure (BHFP) typically is less than the dewpoint pressure of the original reservoir gas. This causes condensate liquid to build up in the reservoir around the wellbore. This paper presents the results of a study of the sampling procedure and of the buildup and stability of the condensate ring around the wellbore. A procedure designed to give the best chance of obtaining a representative sample is presented.

McCain, W.D. Jr.; Alexander, R.A. (Cawley, Gillespie and Associates, Inc. (US))

1992-08-01

44

Inert fluorinated gas T1 calculator  

NASA Astrophysics Data System (ADS)

The physics of spin-rotation interaction in roughly spherical perfluorinated gas molecules has been studied extensively. But, it is difficult to calculate a spin-lattice relaxation time constant T1 for any given temperature and pressure using the published literature. We give a unified parameterization that makes use of the Clausius equation of state, Lennard-Jones collision dynamics, and a formulaic temperature dependence for collision cross section for rotational change. The model fits T1s for SF6, CF4, C2F6, and c-C4F8 for temperatures from 180 to 360 K and pressures from 2 to 210 kPa and in mixtures with other common gases to within our limits of measurement. It also fits previous data tabulated according to known number densities. Given a pressure, temperature, and mixture composition, one can now calculate T1s for common laboratory conditions with a known accuracy, typically 0.5%. Given the success of the model’s formulaic structure, it is likely to apply to even broader ranges of physical conditions and to other gases that relax by spin-rotation interaction.

Kuethe, Dean O.; Pietraß, Tanja; Behr, Volker C.

2005-12-01

45

Evacuation of a Residual Oil Pipeline by Inert Gas Displacement  

Microsoft Academic Search

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

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

1987-01-01

46

Inert gas solubility in binary germania–silica glasses  

Microsoft Academic Search

Helium and neon solubility have been measured in vitreous silica, vitreous germania, and in a series of binary GeO2–SiO2 glasses. Measurements were made over a broad temperature range using a saturation-outgassing method. The enthalpy of solution of these gases is smaller for vitreous germania than for vitreous silica. Inert gas solubility decreases rapidly as silica is initially replaced by germania

Christopher C. Tournour; James E. Shelby

2004-01-01

47

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

Microsoft Academic Search

Gas phase synthesis processes involve the generation of metal atoms through various means, and the homogeneous nucleation and subsequent condensation and coagulation of nanoparticles. Inert gas condensation (IGC) is a desirable process for the synthesis of metal nanoparticles because it is a relatively simple process capable of producing large quantities of nanoparticles, and since it utilizes vacuum deposition, it offers

Colin C. Baker

2004-01-01

48

The use of inert gas as cushion gas in underground storage  

SciTech Connect

In early 1989 there were 395 underground natural gas storage fields in the United States operated by both transmission and distribution companies as an integral part of the gas industry`s delivery system. Base (cushion) gas is required to maintain storage reservoir volume and pressure to ensure adequate deliverability. Base gas is a major investment cost for new storage field development. An inert gas, such as nitrogen, that is less expensive than natural gas can be used to fill all or part of the base gas requirement and yield significant savings in the cost of storage field development. Inert base gas use, tested originally in France, should not dilute the pipeline quality of natural gas withdrawn from storage. The key technical issue is the degree to which natural and inert gases mix in the storage reservoir. The nature of the rock pore spaces that comprise storage fields inhibits the mixing process. A systematic planning approach has been developed to ensure that there are no long-term operating problems with storage fields containing inert base gas. The first field test of inert base gas technology in the US is being planned. The use of inert base gas is a promising technique with the potential to significantly reduce storage investment costs.

Randolph, P.L.; Foh, S.E.

1992-12-31

49

Inert gas analysis of ventilation-perfusion matching during hemodialysis.  

PubMed Central

The mechanism of hypoxemia during hemodialysis was investigated by the multiple inert gas elimination technique in anesthetized, paralyzed, mechanically ventilated dogs. Profound leukopenia occurred in the first hour of a 2-h hemodialysis with a cuprophan membrane and dialysate that contained acetate. Arterial partial pressure of O2 and CO2 and oxygen consumption remained unchanged during dialysis. Pulmonary carbon dioxide elimination and lung respiratory exchange ratio decreased with the initiation of dialysis, remained depressed throughout the duration of dialysis, and returned to predialysis levels after the cessation of dialysis. Cardiac output diminished during dialysis but did not return to base-line levels after dialysis. Multiple indices calculated from inert gas analysis revealed no ventilation-perfusion mismatching during dialysis. The shunt and perfusion to regions of low alveolar ventilation-to-perfusion ratio (VA/Q) were unchanged during dialysis. There was no change in the mean or standard deviation of the profile of the percentage of total perfusion to regions of the lung that had VA/Q near 1.0; nor was there any increase in the directly calculated arterial-alveolar partial pressure differences for the inert gases during dialysis. Dead space became mildly elevated during dialysis. These results show that during dialysis with controlled ventilation there is no ventilation-perfusion mismatching that leads to hypoxemia. During spontaneous ventilation any hypoxemia must occur due to hypoventilation secondary to the CO2 exchange by the dialyzer and subsequent reduction in pulmonary CO2 exchange.

Ralph, D D; Ott, S M; Sherrard, D J; Hlastala, M P

1984-01-01

50

46 CFR 153.462 - Static discharges from inert gas systems.  

Code of Federal Regulations, 2011 CFR

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

2011-10-01

51

46 CFR 153.462 - Static discharges from inert gas systems.  

Code of Federal Regulations, 2012 CFR

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

2012-10-01

52

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..

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

2012-01-01

53

Two methods for calculating regional cerebral blood flow from emission computed tomography of inert gas concentrations  

Microsoft Academic Search

Two methods are described for calculation of regional cerebral blood flow from completed tomographic data of radioactive inert gas distribution in a slice of brain tissue. It is assumed that the tomographic picture gives the average inert gas concentration in each pixel over data collection periods of 30 to 60 sec. In the early picture method a single picture taken

I. Kanno; N. A. Lassen

1979-01-01

54

Characterization of gas condensate mixtures  

SciTech Connect

Simulation of the phase behavior of gas condensate mixtures is a severe test of the employed equation of state and of the C/sub 7+/ - characterization procedure. This paper presents experimental and calculated results for the phase behavior of different gas condensate mixtures, one of which is near critical reservoir conditions. The calculations are based on the Soave-Redlich-Kwong equation of state. For the plus-fraction a continuous logarithmic dependence is assumed for the mole fraction against carbon number. The critical properties of the C/sub 7+/-fractions are calculated directly from measured physical properties of the fractions (molecular weight and density). The procedure is fully predictive. Accurate results are obtained for the phase properties and for the phase compositions. The model may be used successfully also for heavy oil mixtures. It is shown that deviations between the measured and calculated results often can be related to inaccuracies of the data related to the composition in particular of the results for the molecular weight of the plus fraction.

Pedersen, K.S. (CALSEP A/S, Lyngby Hovedgade 29, Dk-2800 Lyngby (DK)); Thomassen, P. (STATOIL, Forus, Postboks 300, N-4001 Stavanger (NO)); Fredenslund, A. (The Technical Univ. of Demark, Dk-2800 Lyngby (DK))

1988-01-01

55

Analysis of Flue Gas Condenser Operation  

NASA Astrophysics Data System (ADS)

The paper is devoted to the problems connected with the use of gas condensers in the wood chips-fuelled boilers. To process the relevant data and evaluate the operation of such a gas condenser, a model was created which involves not only the data derived from performance calculations of the energy source but also the data of experimental measurements; besides, the model contains an evaluation module which allows the efficiency of a gas condenser's operation and the necessary improvements to be determined.

Blumberga, D.; Vigants, E.; Veidenbergs, I.

2011-01-01

56

Inert-gas energy-accommodation coefficients on tungsten  

Microsoft Academic Search

Measurements have been made of the energy-accommodation coefficients for inert gases on the thermally cleaned and partially controllable surface of tungsten at about 300°K under conditions of oil-free pumping.

S. F. Borisov; Yu. G. Semenov; P. E. Suetin

1982-01-01

57

Wellhead gas refrigerator field strips condensate  

Microsoft Academic Search

A new refrigerator system, without moving parts, removes condensates from natural gas at low wellhead pressures of 45 to 435 psi. The thermal separator refrigerates wellhead gas after condensates have been separated in a primary heat exchanger. Field-tested successfully in France, the unique system was developed by the French companies ELF and BERTIN and licensed to NAT SA (Nouvelles Applications

Cotterlaz-Rennaz

1971-01-01

58

Mass transfer in porous injection of an inert gas into a liquid  

NASA Astrophysics Data System (ADS)

Measurements are reported on mass-transfer coefficients for a liquid containing a porous body through which an inert gas is injected. The data are compared with measurements on heat transfer on porous injection and on boiling.

Kuz'min, V. A.; Umbetov, A. S.; Khanaev, V. M.; Kuzin, N. A.; Kirillov, V. A.

1986-09-01

59

Inert Gas Injection as Secondary and Tertiary Recovery Method in the Martha Field in Kentucky  

Microsoft Academic Search

To study the economic feasibility of an inert gas injection process in the low-permeability portion of Martha field, a pilot project was initiated in Dec. 1966. During 3 yr of operation--from 1967 to 1969--77 MMscf, or 20.6 PV, of inert gas has been injected into the formation. As of this date, approx. 12,000 bbl of additional oil has been recovered.

Usman Vadgama; Bill Hinkle

1972-01-01

60

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

Microsoft Academic Search

This introductory review summarises four different aspects of the multiple inert gas elimination technique (MIGET). Firstly, the historical background that facilitated, in the mid 1970s, the development of the MIGET as a tool to obtain more information about the entire spectrum of VA\\/Q distribution in the lung by measuring the exchange of six gases of different solubility in trace concentrations.

J Roca; P D Wagner

1994-01-01

61

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

Microsoft Academic Search

The composition of the gas mixture secreted into the swim-bladders of several species of fish has been determined in the mass spectrometer. The secreted gas dif- fered greatly from the gas mixture breathed by the fish in the relative proportions of the chemically inert gases, argon, neon, helium, and nitrogen. Relative to nitrogen the proportion of the very soluble argon

JONATHAN B. WITTENBERG

1958-01-01

62

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

63

Inert Gas Purification and Measuring Oxygen Partial Pressure in Gas Mixtures with EMF Method Based on Solid Electrolyte Cell.  

National Technical Information Service (NTIS)

Inert atmospheres are often needed in metallurgical and chemical high-temperature experiments to prevent the sample from undesired reactions such as oxidation. Argon gas is readily available and thus the most commonly used medium for this purpose, so the ...

I. Isomaeki

1994-01-01

64

Radiation continuum emitted in the interaction of inert-gas ions with tungsten and molybdenum surfaces  

Microsoft Academic Search

The spectra of visible and ultraviolet radiation produced by inert-gas ions incident on W and Mo surfaces were studied. It was found that the intensity distribution of the radiation was dependent on the target material and the residual gas pressure. (AIP)

S. S. Pop; A. I. Imre; I. P. Zapesochnyi; A. I. Dashchenko; S. A. Evdokimov

1976-01-01

65

Bubble formation resulting from counterdiffusion supersaturation: a possible explanation for isobaric inert gas 'urticaria' and vertigo  

Microsoft Academic Search

In recent simulated diving experiments, subjects have experienced intense itching, confluent maculopapular skin lesions and a severe vestibular derangement with vertigo and nystagmus. These effects have been observed when a gas mixture containing nitrogen or neon is being breathed while a second inert gas, helium, is present in the surrounding environment. Attempts to explain this phenomenon led to a study

D. J. GRAVES; J. IDICULA; C. J. LAMBERTSEN; J. A. QUINN

1973-01-01

66

Inert Gas Washout: Theoretical Background and Clinical Utility in Respiratory Disease  

Microsoft Academic Search

Inert gas washout was first described more than 60 years ago and 2 principal tests have been developed from it: the single breath and multiple breath washout (MBW) techniques. The invention of fast responding gas analysers almost 60 years ago and small computers 30 years later have facilitated breath-by-breath analysis and the development of sophisticated analysis techniques. It is now

Paul D. Robinson; Michael D. Goldman; Per M. Gustafsson

2009-01-01

67

Characteristics of Inert-Gas Discharges During Short-Pulse Operation.  

National Technical Information Service (NTIS)

Inert-gas arc discharges were investigated to determine their spectral and electrical characteristics under the conditions of short-pulse, high-current-density, repetitive operation. The gas fills used were xenon, krypton, and argon at pressures in the or...

W. H. Wright

1970-01-01

68

Federal Helium Program: The Reaction Over An Inert Gas.  

National Technical Information Service (NTIS)

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 author...

J. E. Mielke

1996-01-01

69

The Effect of Mixing and Gravitational Segregation Between Natural Gas and Inert Cushion Gas on the Recovery of Gas from Horizontal Storage Aquifers  

Microsoft Academic Search

It has been proposed in the literature that certain economies might result from the use of an inert cushion gas, such as flue gas, during the storage of natural gas in aquifers. Where cushion gas is used, 2 types of displacement occur: (1) miscible displacement at the natural gas-cushion gas boundary and (2) immiscible displacement at the cushion gas-water interface.

Anil Kumar; Oscar Kimbler

1972-01-01

70

Gas-Phase Aldol Condensation Over Tin on Silica Catalysts.  

National Technical Information Service (NTIS)

Contents: Aldol condensation; Catalyst preparation and composition; Catalyst performance; Kinetics; On the nature of the active site for the aldol condensation over tin on silica catalysts; Gas-phase aldol condensation of n-butanal over tin on silica cata...

J. Venselaar

1980-01-01

71

INERT-GAS TUNGSTEN-ARC WELDING OF TITANIUM FOR NUCLEAR AND CHEMICAL INDUSTRIES  

Microsoft Academic Search

A process has been developed and is described by which unalloyed ; titanium may be field welded using only conventional inert-gas tungsten-arc ; equipment. The process is applicable to the high-quallty individual welds ; required in field welding for the chemical industry rather than to high-speed ; repetitive production welds. (auth)

G. M. Adamson; W. J. Leonard

1958-01-01

72

Modeling, optimization and classification of weld quality in tungsten inert gas welding  

Microsoft Academic Search

In this paper, a neural network is used to construct the relationships between welding process parameters and weld pool geometry in tungsten inert gas (TIG) welding. An optimization algorithm called simulated annealing (SA) is then applied to the network for searching the process parameters with an optimal weld pool geometry. Finally, the quality of aluminum welds based on the weld

Y. S Tarng; H. L Tsai; S. S Yeh

1999-01-01

73

Penetration and capture of low-energy inert gas ions in polycrystalline tungsten  

Microsoft Academic Search

Experimental values of the trapping probability of low-energy inert gas ions in polycrystalline tungsten are presented. This trapping probability is shown to be critically dependent upon the surface topography and the defect state of the tungsten, and it is concluded that experimental data determined without proper regard for these variables cannot be used for informative comparison with theoretically determined values

K. Erents; G. Carter

1968-01-01

74

Study on DC Double Pulse Metal Inert Gas (MIG) Welding of Magnesium Alloy  

Microsoft Academic Search

This article gives a preliminary research on direct current (DC) double pulse metal inert gas (MIG) welding of magnesium alloys. It will be an effort for broadening the application of this new MIG welding process. The unique parameters of DC double pulse MIG welding are selected to investigate their effects on weld bead geometry size and appearance of AZ31B Mg

Zhaodong Zhang; Xiangyu Kong

2012-01-01

75

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

Microsoft Academic Search

This report contains the results of a combined experimental and analytical study of ductile crack growth in tungsten inert gas (TIG) weldments of austenitic stainless steel specimens. The substantially greater yield strength of the weld metal relative to the base metal causes more plastic deformation in the base metal adjacent to the weld than in the weld metal. Accordingly, the

M. Nakagaki; C. Marschall; F. Brust

1986-01-01

76

Heat Intensity and Current Density Distributions at the Anode of High Current, Inert Gas Arcs  

Microsoft Academic Search

Heat transfer intensity and current density distributions at the anode of high current arcs in predominantly inert gas atmospheres were determined experimentally. Measurements were made for stable, axially symmetric arcs having a small diameter refractory metal cathode and a plane, cooled copper anode. The experimental method consisted of splitting the anode, measuring the heat flux and the current to one

O. H. Nestor

1962-01-01

77

Inert gas rejection device for zinc-halogen battery systems  

DOEpatents

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

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

1981-01-01

78

Maximize revenue from gas condensate wells  

SciTech Connect

A computerized oil/gas modeling program called C.O.M.P. allows operators to select the economically optimum producing equipment for a given gas-condensate well-stream. This article, the first of two, discusses use of the model to analyze performance of six different production system on the same wellstream and at the same wellhead conditions. All producing equipment options are unattended wellhead facilities designed for high volume gas-condensate wells and are not gas plants. A second article to appear in September will discuss operating experience with one of the producing systems analyzed, integrated multi-stage separation with stabilization and compression (the HERO system), which was developed by U.S. Enertek, Inc. This equipment was chosen for the wellstream analyzed because of the potential revenue increase indicated by the model.

Hall, S.R.

1988-07-01

79

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

PubMed

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

Lu, Y; Michel, C C; Wang, W

2012-05-17

80

Determination of nitrogen in uranium-plutonium mixed oxide fuel by gas chromatography after fusion in an inert gas atmosphere  

Microsoft Academic Search

A gas chromatographic technique has been developed for the determination of nitrogen in uranium-plutonium mixed oxide fuel after fusion in an inert gas atmosphere. When the sample and pure iron powder in a graphite crucible were heated to approximately 2500 °C by a resistance heating furnace, a large amount of carbon monoxide was evolved with a small amount of nitrogen

Toshiaki Hiyama; Toshio Takahashi; Katsuichiro Kamimura

1997-01-01

81

SALINE BRINES WITH NON-CONDENSIBLE GAS  

Microsoft Academic Search

A new equation-of-state module has been developed for the TOUGH2 simulator, belonging to the MULKOM family of computer codes developed at LBL. This EOS module is able to handle three-component mixtures of water, sodium chloride, and a non-condensible gas. It can describe liquid and gas phases, and 'includes precipitation and dissolution of solid salt. The dependence of density, viscosity, enthalpy,

A. Battistelli; C. Calore; K. Pruess

82

Surface-tension-driven instabilities of a pure liquid layer evaporating into an inert gas  

Microsoft Academic Search

A theoretical model of the evaporation of a pure liquid layer is developed. We focus on the influence of an inert gaseous component, in addition to vapor, on surface-tension-driven Bénard instabilities. It is assumed that the gas phase is perfectly mixed at some distance from the liquid–gas interface (given composition, pressure, and temperature). If this distance is not much larger

Benoît Haut; Pierre Colinet

2005-01-01

83

Inert-gas-bubble formation in the implanted metal\\/Si system  

Microsoft Academic Search

Inert-gas-bubble formation has been observed as a result of ion bombardment of thin metal films (Cr, V, Ni, Ti, or Pd) deposited on Si substrates. Rutherford backscattering measurements and cross-sectional transmission electron microscopic analyses indicated that the gas bubbles were formed predominantly near the interface between the Si substrate and the surface layer. In addition, pronounced mixing between Si and

B. Y. Tsaur; Z. L. Liau; J. W. Mayer; T. T. Sheng

1979-01-01

84

The effect of ion irradiation on inert gas bubble mobility  

SciTech Connect

The effect of Al ion irradiation on the mobility of Xe gas bubbles in Al thin films was investigated. Transmission electron microscopy was used to determine bubble diffusivities in films irradiated and/or annealed at 673K, 723K and 773K. Irradiation increased bubble diffusivity by a factor of 2--9 over that due to thermal annealing alone. The Arrhenius behavior and dose rate dependence of bubble diffusivity are consistent with a radiation enhanced diffusion phenomenon affecting a volume diffusion mechanism of bubble transport. 9 refs., 3 figs., 2 tabs.

Alexander, D.E.; Birtcher, R.C.

1991-09-01

85

Determination of oxygen content in magnesium and its alloys by inert gas fusion-infrared absorptiometry.  

PubMed

A method for the determination of the oxygen content in magnesium and magnesium alloys has been developed. Inert gas fusion-infrared absorptiometry was modified by introducing a multistep heating process; a sample containing oxygen is fused with tin to form an eutectic mixture at 900°C in a graphite crucible, followed by a subsequent gradual temperature increase of up to 2000°C, which enables the evaporation of magnesium from the mixture, and subsequent solidification at the rim of the crucible. Residual tin including magnesium oxide remained at the bottom of the crucible. The oxygen in the tin is measured by a conventional inert gas fusion (IGF) method. From a comparison with the results of charged particle activation analysis, the IGF method is considered to be an attractive candidate for measuring the oxygen content in Mg and its alloys. PMID:21747180

Tsuge, Akira; Achiwa, Hatsumi; Morikawa, Hisashi; Uemoto, Michihisa; Kanematsu, Wataru

2011-01-01

86

Annealing-induced property improvements in 2-14-1 powders produced by inert gas atomization  

SciTech Connect

The effects of vacuum annealing on the phase constitution and magnetic properties of various size fractions of 3 alloy compositions produced by Inert-gas atomization (IGA) are examined. Annealing results in the oxidation of properitectic {alpha}-Fe formed during cooling of the melt, producing considerable improvement in the hard magnetic properties of the powders largely via the removal of lower-anisotropy magnetic reversal regions.

Lewis, L.H. [Brookhaven National Lab., Upton, NY (United States). Dept. of Applied Science; Sellers, C.H. [Lockheed Idaho Technologies Co., Idaho Falls, ID (United States); Panchanathan, V. [Magnequench International Inc., Anderson, IN (United States)

1996-04-01

87

Metastable liquid phase separation in tungsten inert gas and electron beam copper\\/stainless-steel welds  

Microsoft Academic Search

The microstructure of Tungsten Inert Gas (TIG) and electron beam copper\\/stainless-steel welds were investigated using scanning electron microscopy. The relatively high cooling rates entailed in the welding result in high bulk supercooling, causing two microstructural effects: (i) melt separation into two liquids, iron-rich L1, and copper-poor L2, while each solidifies by a path dictated by the stable phase boundary; (ii)

A. Munitz

1995-01-01

88

Thorium232 Exposure during Tungsten Inert Gas Arc Welding and Electrode Sharpening  

Microsoft Academic Search

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 ××××× 10-2 Bq\\/m3 during TIG welding of aluminum (TIG\\/Al), 1.78 × ×× ×× 10-4 Bq\\/m3 during TIG welding of stainless steel (TIG\\/SS),

Hiroyuki SAITO; Naomi HISANAGA; Yukiko OKADA; Shoji HIRAI; Heihachiro ARITO

2003-01-01

89

Temperature field and flow field during tungsten inert gas bead welding of copper alloy onto steel  

Microsoft Academic Search

The temperature field in the base metal and bead-on-plate weld during tungsten inert gas bead welding Hs201 copper alloy onto 35CrMnSiA steel was studied and the fluid flow of the partially melted steel in the molten pool was analyzed. The results show that the thermal cycle changes remarkably and the peak temperature and the cooling speed in the fusion interface

Shixiong Lv; Jianling Song; Haitao Wang; Shiqin Yang

2009-01-01

90

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

Microsoft Academic Search

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

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

1999-01-01

91

Tungsten-inert gas surface alloying of a low carbon steel  

Microsoft Academic Search

In the present study, SAE 1020 steel surface was alloyed with preplaced graphite, chromium and high-carbon-ferro-chromium powders by using a tungsten-inert gas (TIG) heat source, separately. The effects of thickness of the preplaced powder layer on the microstructure, hardness and wear resistance of the alloyed surfaces were investigated. Following the surface alloying, conventional characterization techniques, such as optical microscopy, scanning

M. Ero?lu; N. Özdemir

2002-01-01

92

Characterization of multi-element alloy claddings manufactured by the tungsten inert gas process  

Microsoft Academic Search

Multi-element alloy filler method and the tungsten inert gas (TIG) cladding process were used to fabricate Fe–Co–Cr–Ni–Mox multi-element alloy claddings, and the microstructure and wear properties of the claddings were studied.In the absence of Mo, the claddings formed a face-centered-cubic (FCC) solid-solution phase. When the Mo concentration was increased, the claddings comprised not only the primary FCC phase but also

J. H. Chen; P. N. Chen; C. M. Lin; C. M. Chang; Y. Y. Chang; W. Wu

2009-01-01

93

Fatigue behaviour of T welded joints rehabilitated by tungsten inert gas and plasma dressing  

Microsoft Academic Search

This paper concerns a fatigue study on the effect of tungsten inert gas (TIG) and plasma dressing in non-load-carrying fillet welds of structural steel with medium strength. The fatigue tests were performed in three point bending at the main plate under constant amplitude loading, with a stress ratio of R=0.05 and a frequency of 7Hz.Fatigue results are presented in the

Armando L. Ramalho; José A. M. Ferreira; Carlos A. G. M. Branco

2011-01-01

94

Structural integrity of copper-nickel to steel using metal inert gas welding  

Microsoft Academic Search

Metal inert gas (MIG) welding may be used as a technique to attach copper-nickel panels to steel substrates to minimize the\\u000a corrosion and biofouling of offshore structures and ship hulls. A series of plug welds must be located on each panel in order\\u000a to eliminate bowing when the panels are subjected to compressive loadings. Laboratory tests on MIG plug-welded specimens

T. S. Sudarshan; J. H. Wilson; S. M. Fisher

1986-01-01

95

Microstructure and magnetic properties of inert gas atomized rare earth permanent magnetic materials  

Microsoft Academic Search

Several permanent magnet alloys based on the ternary NdâFeââB (2-14-1) composition have been prepared by inert gas atomization (IGA). The microstructure and magnetic properties of these alloys have been studied as a function of particle size, both before and after heat treatment. Different particle sizes have characteristic properties due to the differences in cooling rate experienced during solidification from the

C. H. Sellers; T. A. Hyde; D. J. Branagan; L. H. Lewis; V. Panchanathan

1997-01-01

96

Microstructure and magnetic properties of inert gas atomized rare earth permanent magnetic materials  

Microsoft Academic Search

Several permanent magnet alloys based on the ternary Nd2Fe14B (2-14-1) composition have been prepared by inert gas atomization (IGA). The microstructure and magnetic properties of these alloys have been studied as a function of particle size, both before and after heat treatment. Different particle sizes have characteristic properties due to the differences in cooling rate experienced during solidification from the

C. H. Sellers; T. A. Hyde; D. J. Branagan; L. H. Lewis; V. Panchanathan

1997-01-01

97

Determination of air-water partitioning of volatile halogenated hydrocarbons by the inert gas stripping method  

Microsoft Academic Search

Air-water partitioning for 21 volatile chlorinated or brominated alkanes, alkenes, and aromatics was measured at 20 C by the inert gas stripping method. Results of the measurements are presented in the form of Henry`s law constants (Hââ), air-water partition coefficients (K{sub aw}), and limiting activity coefficients (γ), accurate γ values being obtained only if accurate pure solute vapor pressure data

S. Hovorka; Vladimír Dohnal

1997-01-01

98

Unstructured Adaptive Grid Flow Simulations of Inert and Reactive Gas Mixtures  

Microsoft Academic Search

Unstructured adaptive grid flow simulation is applied to the calculation of high-speed compressible flows of inert and reactive gas mixtures. In the present case, the flowfield is simulated using the 2-D Euler equations, which are discretized in a cell-centered finite volume procedure on unstructured triangular meshes. Interface fluxes are calculated by a Liou flux vector splitting scheme which has been

L. F. Figueira da Silva; João L. F. Azevedo; Heidi Korzenowski

2000-01-01

99

Improving Well Productivity in Gas Condensate Reservoirs via Chemical Treatment  

Microsoft Academic Search

Condensate dropout and accumulation along with high water saturation near the wellbore region result in a decrease in the gas relative permeability. This permeability is a function of fluid saturations interfacial tension (IFT and rock wettability between the condensate and gas. The need to mitigate the reduction in well productivity caused by condensate build up below the dew point is

Mukul Sharma; Vishal Bang; Mohabbat Ahmadi; Harry Linnemeyer

100

A device for vacuum drying, inert gas backfilling and solder sealing of hermetic implant packages.  

PubMed

Modern implanted devices utilize microelectronics that have to be protected from the body fluids in order to maintain their functionality over decades. Moisture protection of implants is addressed by enclosing the electronic circuits into gas-tight packages. In this paper we describe a device that allows custom-built hermetic implant packages to be vacuum-dried (removing residual moisture from inside the package), backfilled with an inert gas at adjustable pressure and hermetically sealed employing a solder seal. A typical operation procedure of the device is presented. PMID:21096385

Schuettler, Martin; Huegle, Matthias; Ordonez, Juan S; Wilde, Juergen; Stieglitz, Thomas

2010-01-01

101

Quantum gas-liquid condensation in an attractive Bose gas  

SciTech Connect

Gas-liquid condensation (GLC) in an attractive Bose gas is studied on the basis of statistical mechanics. Using some results in combinatorial mathematics, the following are derived. (1) With decreasing temperature, the Bose-statistical coherence grows in the many-body wave function, which gives rise to the divergence of the grand partition function prior to Bose-Einstein condensation. It is a quantum-mechanical analogue to the GLC in a classical gas (quantum GLC). (2) This GLC is triggered by the bosons with zero momentum. Compared with the classical GLC, an incomparably weaker attractive force creates it. For the system showing the quantum GLC, we discuss a cold helium 4 gas at sufficiently low pressure.

Koh, Shun-ichiro [Physics Division, Faculty of Education, Kochi University, Akebono-cho, 2-5-1, Kochi 780 (Japan)

2005-07-01

102

Pulsed laser deposition of antifriction thin-film coatings in vacuum and inert gas  

NASA Astrophysics Data System (ADS)

MoSex coatings were obtained by pulsed laser deposition in vacuum and inert Ar gas atmosphere at the pressure from 1 to 10 Pa. The deposition temperature was 200°C. The films were studied by means of X-ray diffraction, scanning and transmission electron spectroscopy, X-ray photoelectron spectroscopy, Rutherford backscattering spectroscopy of helium ions. The tribological properties of thin film coatings were investigated by pin-on-disk testing in air with 50% relative humidity. Chemical composition, structure, and tribological properties of the coatings were found to be sensitive to the presence of the inert gas. Thus, increasing the gas pressure from 1 to 10 Pa changes the chemical composition, so that the value of x increases from 1.5 to 2.4 in the principal deposition zone. At the optimal gas pressure (~ 2 Pa), the composition of the coating was close to the stoichiometric one, and the layer adjacent to the substrate consisted of MoSex nano-crystals with the basal planes parallel to the substrate surface or oriented at small angles to the surface. The tribological properties of MoSex coatings deposited on steel substrates depend on the gas pressure. The friction coefficient in air decreases from 0.08 for deposition in vacuum to 0.04 for deposition at the optimal pressure.

Fominski, V.; Romanov, R.; Kostitchev, I.

2007-07-01

103

A Model for Surface Induced Growth of Inert Gas Bubbles in Irradiated Copper-Boron Alloys  

SciTech Connect

A matrix containing inert gas bubbles dilates in direct proportion to the growth experienced by the gas bubbles. This phenomenon is termed as swelling. A model for the swelling induced by the growth of the helium gas bubbles in irradiated copper-boron alloys is presented. The bubbles grow by acquiring vacancies from the external surface, which acts as a source of vacancies. The vacancies reach the surface of the bubbles mainly via lattice diffusion and to a limited extent via diffusion through short-circuiting paths such as grain boundaries and dislocation pipes. The model predicts that overall swelling of the matrix varies as 1.5 power of time. Another consequence of the present model is that the growth rate of a gas bubble varies inversely as the cube of its distance from the external surface. The model has been applied to the data on irradiated copper-boron alloys and found to be in accord with the experimental results. The model is general and can be applied to the growth of all kinds of stationary inert gas bubbles trapped within a crystalline matrix. (authors)

Tiwari, G.P.; Ramadasan, E. [Post Irradiation Examination Division, Bhabha Atomic Research Division (India)

2006-07-01

104

Numerical Study on Feasibility of Pulsed-Heat-Source High-Temperature Inert Gas MHD Electrical Power Generation  

Microsoft Academic Search

The performance of a pulsed-heat-source, high-temperature inert gas MHD electrical power generator, which is a candidate space-based laser-to-electrical power converter, is examined by time-dependent, quasi-one dimensional, numerical simulation. In the present MHD generator, the inert gas is assumed to be ideally pulse heated to about 104 K within a short time (˜1 mus) in a stagnant energy input volume. The

Masaharu Matsumoto; Tomoyuki Murakami; Yoshihiro Okuno

2008-01-01

105

Structural peculiarities and molecular properties of charge complexes formed on positive ion injection into dense inert gas media  

Microsoft Academic Search

The formation of charge complexes resulting from penetration of positive ions into the dense inert gas media is modelled on the basis of Hartree-Fock-Roothaan method calculations of the potential energy surface of proton interaction with n inert gas atoms R. It is shown that molecular ions of the type RH(+), R2H(+) with binding energy D(sub E) is greater than or

S. G. Potapov; L. P. Suchanov; G. L. Gutsev

1988-01-01

106

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

107

Laboratory Study of Gas-Fueled Condensing Furnaces.  

National Technical Information Service (NTIS)

The objective of the study was to determine if the direct measurement method of condensate collection that was developed during prior testing of a condensing boiler would be adequate for direct measurement of the condensate from gas fueled forced warm air...

E. R. Kweller R. A. Wise

1985-01-01

108

Single-electron capture cross-sections for W+ and W2+ ions colliding with inert gas and hydro-carbon molecular gas targets  

Microsoft Academic Search

Absolute cross-sections for single-electron capture collisions of singly and doubly charged tungsten ions with inert gas (He, Ne, Ar, and Kr) and hydro-carbon gas (H2, CH4, C2H6, and C3H8) targets were derived experimentally. The measured cross-sections show strong power-law dependence on the first ionization potential of the target, whose slopes are independently identical to inert and hydro-carbon gas targets.

Makoto Imai; Yoshitaka Iriki; Y. Kikuchi; A. Itoh

2009-01-01

109

Field adsorption of inert gas atoms on the tungsten surface: A pulsed-laser atom-probe study  

Microsoft Academic Search

On a solid surface, inert gas atoms can be field adsorbed to the surface under the influence of a strong electric field. The probability of field adsorption was measured as a function of temperature for He, Ne, and Ar on the W(112) surface. Although it was assumed that gas atoms field adsorb only on top of surface atoms, experimental evidence

T. J. Kinkus; T. T. Tsong

1985-01-01

110

Spectroscopic analysis of the plasma created by a double-flux tungsten inert gas (TIG) arc plasma torch  

Microsoft Academic Search

Measurements of population densities and temperature distributions have been performed in a double-flux tungsten inert gas (TIG) arc plasma column using high-resolution spectroscopy. The experimental conditions have been chosen to mimic typical welding conditions with argon gas. The results show that the plasma is dominated by metallic vapour species in the vicinity of the molten anode, while a nearly pure

D. Degout; A. Catherinot

1986-01-01

111

Changes in inert gas rebreathing parameters after ozone exposure in dogs  

SciTech Connect

The acute (30 min postexposure) and delayed (24 and 48 h postexposure) effects of a 4-h exposure to 1.0 ppm O/sub 3/, 0.3 ppm O/sub 3/ were evaluated using an inert multiple gas rebreathing method as well as arterial blood gas determinations in anesthetized dogs. Rebreathing parameters included pulmonary capillary blood flow (Qc), diffusing capacity, functional residual capacity, pulmonary tissue plus capillary blood volume (VTPC), and oxygen consumption. The Qc and PaO/sub 2/ were significantly decreased 30 min after exposure to O/sub 3/ and remained decreased 24 and 48 h after exposure only in the 1.0 ppm O/sub 3/ group. After exposure to 1.0 ppm O/sub 3/ only, a 33% increase in VTPC was found at 24 but not at 48 h and was confirmed by autopsy lung water determinations. No changes in rebreathing parameters or arterial blood gas measurements occurred in the air exposure control group. Therefore, an acute exposure to O/sub 3/ resulted in adverse cardiopulmonary effects in dogs. Five additional dogs were exposed to 1.0 ppm O/sub 3/ for 4 h while breathing spontaneously rather than with ventilation being assisted by electrophrenic stimulation (as done in the other exposures), and no changes in VTPC occurred. Thus, the ventilatory pattern used during O/sub 3/ exposure is also an important factor in causing critical degrees of parenchymal lung injury.

Friedman, M.; Gallo, J.M.; Nichols, H.P.; Bromberg, P.A.

1983-11-01

112

Kinetics of inert gas equilibration in an exclusively skin-breathing salamander, Desmognathus fuscus.  

PubMed

Characteristics of cutaneous gas exchange in amphibians were studied by analysis of the equilibration kinetics of an inert test gas in salamanders which have neither lungs nor gills. Specimens of the common dusky salamander (Desmognathus fuscus, Plethodontidae, Urodela), average body mass 6.1 g were equilibrated with 20% chlorodifluoromethane (Freon 22) in oxygen. The time course of subsequent elimination of Freon 22 into atmospheric air was more rapid in living than in dead animals. This difference was attributed to convective transport by blood flow. Several alternative models were proposed, providing a basis for quantitative analysis of the data. All models yielded similar values for convective conductance due to blood flow. In order to calculate blood flow therefrom, a simplified circulation model based on anatomical evidence was used: the cardiac output is in part directed to the skin, subserving gas exchange with the environment, and in part to the internal organs; the blood returning from both skin and internal organs is mixed before reaching the heart. Depending on assumptions regarding the model and the partitioning of blood flow to the skin and to internal organs, the following range of values was calculated from the experimental data: cardiac output, 85-195 mul/(min-g body mass); cutaneous blood flow, 27-63 mul/(min-g body mass). Due to inherent assumptions these values must be considered minimum estimates. PMID:1197944

Gatz, R N; Crawford, E C; Piiper, J

1975-06-01

113

Fusao a arco sob atmosfera de gas inerte da esponja de zirconio. (Arc melting in inert gas atmosphere of zirconium sponge).  

National Technical Information Service (NTIS)

The obtainment of metallic zirconium in laboratory scale with commercial and nuclear quality is the objective of the Metallurgy Department of IEN/CNEN - Brazil, so a melting procedure of zirconium sponge in laboratory scale using an arc furnace in inert a...

O. Julio Junior A. H. P. Andrade

1991-01-01

114

Efeito Do Gas Inerte na Queima de Polvora de Base Dupla (Effect of Inert Gas on the Burning of Double Base Powder).  

National Technical Information Service (NTIS)

Demonstrated is the lack of influence of the inert monatomic gases, helium and argon, on the burning rate of a solid propellant. It is concluded that the control mechanism of the combustion of the solid propellant is in the liquid or solid phase of the fl...

F. Fachinifilho W. Gill L. Dealbuquerquekimura

1987-01-01

115

Condensation of an ideal gas obeying non-Abelian statistics  

NASA Astrophysics Data System (ADS)

We consider the thermodynamic geometry of an ideal non-Abelian gas. We show that, for a certain value of the fractional parameter and at the relevant maximum value of fugacity, the thermodynamic curvature has a singular point. This indicates a condensation such as Bose-Einstein condensation for non-Abelian statistics and we work out the phase transition temperature in various dimensions.

Mirza, Behrouz; Mohammadzadeh, Hosein

2011-09-01

116

Employment of acoustic emission for the control of the tungsten-inert gas welding process of high-alloy steel  

Microsoft Academic Search

Many high-alloy steels are welded with the aid of a tungsten-inert gas procedure. The problems which occur in connection with the use of this welding method require, however, usually a nondestructive inspection of the weld. The acoustic emission analysis provides an appropriate method for such an inspection. A description is presented of a number of experiments which were conducted with

K.-F. Walder; H.-D. Steffens; H.-A. Crostack

1978-01-01

117

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

Microsoft Academic Search

In this study, the effects of heat input on the distribution of microhardness of tungsten inert gas (TIG) arc welded hot-extruded AZ61 magnesium alloy joints were investigated. The results show that with an increase of heat input, the distributions of microhardness at the top and bottom of the welded joints are different because they are determined by both the effect

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

2010-01-01

118

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

Microsoft Academic Search

Laser beam cutting of sheet metal requires an assist gas to blow away the molten material. Since the assist-gas dynamics influences the quality and speed of the cut, the orientation of the gas nozzle with respect to the kerf is also expected to be important. A 1 kW cw CO2 laser with nitrogen assist gas was used to cut mild

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

1996-01-01

119

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

NASA Astrophysics Data System (ADS)

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

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

1992-06-01

120

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

NASA Astrophysics Data System (ADS)

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

Whitehead, John C.; Lanning, Rodney K.; Evans, Mark C.; Barabas, Neil J.

1992-07-01

121

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

122

A condensed gas–phase chemical model and its application  

Microsoft Academic Search

Using the “lumped mechanism” and “counting species” methods, we developed a condensed gas-phase chemical model based on a\\u000a simplified one. The modified quasi-steady-state approximation (QSSA) scheme and the error redistribution mass conservation\\u000a technique are adopted to solve the atmospheric chemistry kinetic equations. Results show that the condensed model can well\\u000a simulate concentration variations of gas species such as SO2, NOX,

Tijian Wang; Zhaobo Sun; Zongkai Li

1999-01-01

123

Microstructure and magnetic properties of inert gas atomized rare earth permanent magnetic materials  

SciTech Connect

Several permanent magnet alloys based on the ternary Nd{sub 2}Fe{sub 14}B (2-14-1) composition have been prepared by inert gas atomization (IGA). The microstructure and magnetic properties of these alloys have been studied as a function of particle size, both before and after heat treatment. Different particle sizes have characteristic properties due to the differences in cooling rate experienced during solidification from the melt. These properties are also strongly dependent on the alloy composition due to the cooling rate{close_quote}s effect on the development of the phase structure; the use of rare earth rich compositions appears necessary to compensate for a generally inadequate cooling rate. After atomization, a brief heat treatment is necessary for the development of the optimal microstructure and magnetic properties, as seen from the hysteresis loop shape and improvements in key magnetic parameters (intrinsic coercivity H{sub ci}, remanence B{sub r}, and maximum energy product BH{sub max}). By adjusting alloy compositions specifically for this process, magnetically isotropic powders with good magnetic properties can be obtained and opportunities for the achievement of better properties appear to be possible. {copyright} {ital 1997 American Institute of Physics.}

Sellers, C.H.; Hyde, T.A.; Branagan, D.J. [Idaho National Engineering Laboratory, Idaho Falls, Idaho 83402-2211 (United States); Lewis, L.H. [Department of Applied Science, Materials Science Division, Brookhaven National Laboratory, Upton, New York 11973-5000 (United States); Panchanathan, V. [Magnequench International, Anderson, Indiana 46013 (United States)

1997-02-01

124

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

125

Unstructured Adaptive Grid Flow Simulations of Inert and Reactive Gas Mixtures  

NASA Astrophysics Data System (ADS)

Unstructured adaptive grid flow simulation is applied to the calculation of high-speed compressible flows of inert and reactive gas mixtures. In the present case, the flowfield is simulated using the 2-D Euler equations, which are discretized in a cell-centered finite volume procedure on unstructured triangular meshes. Interface fluxes are calculated by a Liou flux vector splitting scheme which has been adapted to an unstructured grid context by the authors. Physicochemical properties are functions of the local mixture composition, temperature, and pressure, which are computed using the CHEMKIN-II subroutines. Computational results are presented for the case of premixed hydrogen-air supersonic flow over a 2-D wedge. In such a configuration, combustion may be triggered behind the oblique shock wave and transition to an oblique detonation wave is eventually obtained. It is shown that the solution adaptive procedure implemented is able to correctly define the important wave fronts. A parametric analysis of the influence of the adaptation parameters on the computed solution is performed.

Figueira da Silva, L. F.; Azevedo, João L. F.; Korzenowski, Heidi

2000-05-01

126

Unstructured adaptive grid flow simulations of inert and reactive gas mixtures  

SciTech Connect

Unstructured adaptive grid flow simulation is applied to the calculation of high-speed compressible flows of inert and reactive gas mixtures. In the present case, the flowfield is simulated using the 2-D Euler equations, which are discretized in a cell-centered finite volume procedure on unstructured triangular meshes. Interface fluxes are calculated by a Liou flux vector splitting scheme which has been adapted to an unstructured grid context by the authors. Physicochemical properties are functions of the local mixture composition, temperature, and pressure, which are computed using the CHEMKIN-II subroutines. Computational results are presented for the case of premixed hydrogen-air supersonic flow over a 2-D wedge. In such a configuration, combustion may be triggered behind the oblique shock wave and transition to an oblique detonation wave is eventually obtained. It is shown that the solution adaptive procedure implemented is able to correctly define the important wave fronts. A parametric analysis of the influence of the adaptation parameters on the computed solution is performed.

Figueira da Silva, L.F.; Azevedo, J.L.F.; Korzenowski, H.

2000-05-20

127

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

SciTech Connect

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

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

1986-12-01

128

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

NASA Astrophysics Data System (ADS)

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

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

1996-11-01

129

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

SciTech Connect

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

Bokhan, P. A.; Zakrevsky, Dm. E. [Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Sciences, Prospekt Lavrent'eva 13, 630090 Novosibirsk (Russian Federation)

2010-08-30

130

Condensation of an ideal gas obeying non-Abelian statistics.  

PubMed

We consider the thermodynamic geometry of an ideal non-Abelian gas. We show that, for a certain value of the fractional parameter and at the relevant maximum value of fugacity, the thermodynamic curvature has a singular point. This indicates a condensation such as Bose-Einstein condensation for non-Abelian statistics and we work out the phase transition temperature in various dimensions. PMID:22060335

Mirza, Behrouz; Mohammadzadeh, Hosein

2011-09-13

131

Ultrasonic Measurements on Quench—Condensed Noble Gas Films  

Microsoft Academic Search

Quench–condensed noble gas films are a simple model system for studying the elastic properties of polycrystalline or amorphous solids at low temperatures. We have investigated the temperature dependence of the sound velocity dv\\/v and attenuation a of quench–condensed polycrystalline Ar, Ne, and HD films using surface acoustic waves at 800 MHz. Up to 0.7 K the sound velocity of all

G. Weiss; K. Eschenröder; J. Classen; S. Hunklinger

1998-01-01

132

Influence of TIG welding thermal cycles on HSLA100 steel plate. Technical report. [TIG (tungsten-inert gas)  

Microsoft Academic Search

A series of five bead on plate autogenous tungsten-inert-gas (TIG) welds were performed on U.S. Navy HSLA-100 steel. Power variations in these welds was achieved by altering the welding speed, voltage and current and were as follows (in kJ\\/mm); 0.7, 1.1, 1.2, 1.6 and 2.2. No evidence was found of either weld metal or underbead HAZ cracking in any of

A. G. Fox; S. D. Bhole

1993-01-01

133

Formation of ZrC ablation protective coatings on carbon material by tungsten inert gas cladding technique  

Microsoft Academic Search

Continuous, uniform, crack-free ZrC protective coatings have been deposited by a novel tungsten inert gas cladding technique on graphitic carbon substrates through the reaction of graphitic carbon with ZrO2. The phase composition, microstructure, and ablation performance have been researched. Cross-section morphology revealed that an excellent bond was formed at the coating\\/substrate interface. Ablation loss tests showed samples coated by tungsten

G. Wen; S. H. Sui; L. Song; X. Y. Wang; L. Xia

2010-01-01

134

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

Microsoft Academic Search

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

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

2006-01-01

135

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

Microsoft Academic Search

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

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

2006-01-01

136

Modeling of the mechanical effects induced by the tungsten inert-gas welding of the IN718 superalloy  

Microsoft Academic Search

The distortion and residual stresses arising during the tungsten inert-gas (TIG) welding of the nickel-based superalloy IN718\\u000a are modeled using sequentially coupled thermal-mechanical analyses. Processing trials have been carried out for validation\\u000a purposes, and, for a number of rectilinear testpieces, the distortion has been quantified. The residual stresses in one of\\u000a the welds have been characterized using the neutron diffraction

D. Dye; O. Hunziker; S. M. Roberts; R. C. Reed

2001-01-01

137

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

138

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

PubMed

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

McElearney, N; Irvine, D

1993-07-01

139

Reflux condenser mode with non-condensible gas: assessment of CATHARE against BETHSY test 7.2C.  

National Technical Information Service (NTIS)

The condensation process in the Steam Generator (SG) U-tubes with the presence of non-condensable gas (nitrogen) has been investigated on the Bethsy integral test facility. Bethsy test 7.2c dealing with Reflux Condenser mode consists of a succession of st...

B. Noel R. Deruaz

1993-01-01

140

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

141

Investigation of the Gas Condensate Produced in Underground Gasification of Coal.  

National Technical Information Service (NTIS)

The gas condensate of the Angren underground station is a condensation product of the moisture present in the gas produced in underground gasification. The moisture present in the gas condenses gradually as the gas moves through the line and the cooling s...

K. I. Gridneva E. F. Krymskaya

1969-01-01

142

Gas condensate reservoir characterisation for CO2 geological storage  

NASA Astrophysics Data System (ADS)

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

Ivakhnenko, A. P.

2012-04-01

143

Condensed phase decomposition and gas phase combustion of hydrazinium nitroformate  

Microsoft Academic Search

This paper presents the results of a series of experiments on the condensed phase decomposition and the gas phase combustion of hydrazinium nitroformate (HNF). The experiments include SEM analysis of quenched samples that showed evidence of the formation of a foam layer. FTIR spectrometry and mass spectrometry provide details on species formation during decomposition and combustion. The analysis of the

O. E. Dragomir; M. J. Tummers; E. H. van Veen; A. E. D. M. van der Heijden; D. J. E. M. Roekaerts

2009-01-01

144

Preparation of Binary Ice Layers by Condensation from Gas Phase.  

National Technical Information Service (NTIS)

Binary ice layers of H2O/NH3, H2O/CO2, NH3/CO2 (77 K), and H2O/CH4 (10 K) are prepared by condensing gas mixtures of defined composition onto a cold KBr plate in a cryostat at a vacuum of about 0.00001 mbar. Layer thickness and composition are determined ...

E. Biel A. Patnaik K. Roessler

1988-01-01

145

PROCEDURE FOR MEASURING FREON 114 LEAK RATES IN CASCADE COOLANT CONDENSERS BY THE GAS DILUTION METHOD  

Microsoft Academic Search

The gas dilution method for the measurement of Freon leak rates to the ; water side of cascade coolant condensers has been tested on various condensers in ; the X-333 building and on one condenser in the X-330 building. The gas dilution ; method involves injecting Freon 115 (CClFâ--CFâ) into the water inlet ; of a condenser suspected of leaking

1958-01-01

146

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

147

A method for calculating regional cerebral blood flow from emission computed tomography of inert gas concentrations  

Microsoft Academic Search

Emission tomography of positron or gamma emitting inert gases allows calculation of regional cerebral blood flow (rCBF) in cross-sectional slices of human brain. An algorithm is presented for rCBF calculations from a sequence of time averaged tomograms using inhaled 133Xe. The approach is designed to avoid loss of information in brain areas with low flow rates. It is based on

P. Celsis; T. Goldman; L. Henriksen; N. A. Lassen

1981-01-01

148

Effect of non-condensable gas on condensation in a highly-rotating drum with a scraper  

NASA Astrophysics Data System (ADS)

The effect of non-condensable gas on condensation in a highly rotating drum with a scraper is explored analytically. The formulation is first carried out generally, and then the application of the general formulation to the steam-air system gives heat transfer results for a wide range of operating conditions. It is found that a very small amount of non-condensable gas can induce a significant reduction in heat transfer. The reduction is accentuated at larger temperature differences, thinner condensate thickness and, to one's surprise, at higher operating pressures. By comparison, it is indicated that the present situation is more sensitive to non-condensable gas than forced convection condensation along a horizontal plate.

Zhong, M. K.; Mizukami, K.

149

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

DOEpatents

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

Bitensky, M.W.; Yoshida, Tatsuro

1997-04-29

150

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

Microsoft Academic Search

Well productivity in gas condensate reservoirs is reduced by condensate banking when the bottom hole flowing pressure drops below the dewpoint pressure. Several methods have been proposed to restore gas production rates after a decline due to condensate blocking. Gas injection, hydraulic fracturing, horizontal wells and methanol injection have been tried with limited success. These methods of well stimulation either

Viren Kumar

2006-01-01

151

Condensation  

NSDL National Science Digital Library

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

Kessler, James H.; Galvan, Patricia M.

2007-01-01

152

Maximize revenue from gas condensate wells  

SciTech Connect

A computerized oil/gas modeling program called C.O.M.P. was used to analyze comparative recovery, losses and revenues from six different producing systems on a given wellstream as tested on initial completion. A multi-stage separation/stabilization/compression system (HERO system) manufactured by U.S. Enertek, Inc., was subsequently installed to produce the well, plus five other wells in the immediate area. This article compares theoretical gains forecast by the modeling program with actual gains recorded during later testing of the same well with a two-stage separation hookup and the multi-stage unit. The test using two-stage separation was run as a basis for comparison. Operating temperatures and pressures for each test are shown.

Hall, S.R. (U.S. Enertek, Inc., Farmington, NM (US))

1988-09-01

153

The effect of hydrogen shielding gas on microstructure and abrasive wear behavior in the surface modification process using the tungsten inert gas method  

Microsoft Academic Search

In this study, SAE 1020 steel surfaces were separately alloyed with preplaced high-carbon ferro-chromium (FeCr), ferro-molybdenum\\u000a (FeMo), and ferro-titanium (FeTi) powders by using a tungsten inert gas (TIG) heat source. By using two different types of\\u000a shielding gas compositions during the alloying process, the study investigated the effects of modified shielding gas composition\\u000a on the microstructure, hardness, and abrasive wear

V. V. Cay; S. Ozan; M. S. Gök

2011-01-01

154

The development study on gas recycling injection in Yaha Gas Condensate Field, Tarim Basin, China  

Microsoft Academic Search

The Yaha Gas Condensate Field is the largest one discovered in China so far. In order to enhance the condensate recovery,\\u000a gas recycling at 50 MPa has been implemented in Yaha field. Such high-pressure injection is very rare throughout the world.\\u000a This paper offers the description of the geology and fluid phase behavior of Yaha field. The reservoir productivity and

Sun Longde; Song Wenjie; Jiang Tongwen

2003-01-01

155

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

156

Optical condensation measurement in gas turbine engine inlets  

Microsoft Academic Search

A non-intrusive optical system for the measurement of air inlet condensation in gas turbine engines is presented. The system uses a technique in which a linear relationship between the liquid water content (LWC) and the optical extinction coefficient exists. The extinction coefficient was determined by measuring the extinction of a 10.6 micrometers CO2 laser beam due to Mie scattering from

Jason Potter; Ralph P. Tatam

1997-01-01

157

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

158

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

SciTech Connect

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

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

2010-12-20

159

CATHODES FOR LOW TEMPERATURE SOFC: ISSUES CONCERNING INTERFERENCE FROM INERT GAS ADSORPTION AND CHARGE TRANSFER  

SciTech Connect

This report summarizes the work done on the project over the duration of the project, from October 1, 2002 through December 31, 2003, which includes a three month no-cost extension. Effort was directed in the following areas: (1) Fabrication of Sr-doped LaCoO3 (LSC) dense and porous samples. (2) Design and construction of a conductivity relaxation apparatus for the estimation of surface exchange coefficient, k{sub chem}, which depends on adsorption, and oxygen chemical diffusion coefficient, {tilde D}{sub 0}, the parameters which are thought to describe the cathodic activation polarization (overall charge transfer) in mixed ionic electronic conducting (MIEC) cathodes. (3) The measurement of and K{sub chem} and {tilde D}{sub 0} on LSC by conductivity relaxation, as a function of temperature and oxygen partial pressure, p{sub O{sub 2}}. (4) Fabrication of YSZ electrolyte discs with patterned LSM and LSC electrodes with three-phase boundary (TPB) length, l{sub TPB}, varying between 50 and 1200 cm{sup -1}. (5) The measurement of charge transfer resistance, R{sub ct}, and estimation of the charge transfer resistivity, {rho}{sub ct}, as a function of temperature and p{sub O{sub 2}}, and the incorporation of the adsorption step in the analysis. (6) Preliminary cell tests with oxidants having different inert gas diluents; N{sub 2}, Ar, and CO{sub 2}. Dense samples of LSC of thickness as small as 150 microns were fabricated by sintering followed by grinding. Porous samples of LSC were also fabricated wherein the porosity was {approx}30%. Both samples were used in conductivity relaxation experiments. Analysis of data from the dense samples gives both and k{sub chem} and {tilde D}{sub 0}, while that of porous samples gives k{sub chem}. It was observed that at a given temperature, k{sub chem} increases with increasing p{sub O{sub 2}}, while the {tilde D}{sub 0} is essentially a constant. The dependence of k{sub chem} on p{sub O{sub 2}} is attributed to the adsorption step. It was also observed that the porous samples gave a more accurate measurement of k{sub chem}, as the data were not influenced by {tilde D}{sub 0}. By contrast, the results on dense samples were influenced by {tilde D}{sub 0}, especially at lower temperatures. It is thus concluded that the use of porous samples is preferred for the measurement of k{sub chem}. In the case of composite electrodes, such as LSM + YSZ, the relevant parameters are the {rho}{sub ct} (or R{sub ct}) and the ionic resistivity of YSZ {rho}{sub i}, where 1/{rho}{sub ct} is analogous to k{sub chem} and 1/{rho}{sub i} is analogous to {tilde D}{sub 0}. LSM patterned electrodes were deposited on YSZ discs using photomicrolithography. The R{sub ct} was measured as a function of temperature and p{sub O{sub 2}}using complex impedance techniques, on samples with l{sub TPB} varying between 50 and 1200 cm{sup -1}. The plot of 1/R{sub ct} vs. l{sub TPB} was linear, consistent with the occurrence of charge transfer at TPB. Also, the data plotted on the assumption of dissociative adsorption was consistent with the model. The significance of the role of adsorption is discussed. Similar results were observed with LSC, indicating a similar role of adsorption. In the case of LSC, however, a significant transport of oxygen also occurs through the dense part of the electrode. Preliminary work was conducted on the testing of button cells with mixtures of O{sub 2} + N{sub 2}, O{sub 2} + Ar, and O{sub 2} + CO{sub 2} as oxidants, wherein the p{sub O{sub 2}} was varied between {approx}0.05 and {approx}1.0 atm. As expected, the results showed that the higher the p{sub O{sub 2}}, the better was the performance. In pure oxygen, the maximum power density at 800 C was {approx}2.9 W/cm{sup 2}. However, in 5% O{sub 2}, it was {approx}0.6 W/cm{sup 2}. This difference is attributed to adsorption, indicating that both charge transfer and adsorption needs to be addressed in order to improve cathode performance at lower temperatures and under high oxidant utilization (in low p{sub O{sub 2}} atmospheres). Data at low current dens

Anil V. Virkar

2004-05-05

160

Optical condensation measurement in gas turbine engine inlets  

NASA Astrophysics Data System (ADS)

A non-intrusive optical system for the measurement of air inlet condensation in gas turbine engines is presented. The system uses a technique in which a linear relationship between the liquid water content (LWC) and the optical extinction coefficient exists. The extinction coefficient was determined by measuring the extinction of a 10.6 micrometers CO2 laser beam due to Mie scattering from water droplets and the LWC calculated from the linear relationship. Results of the extinction coefficient determined with the system used in a single transmission path mode on a condensing flow occurring in the inlet of a subsonic suction tunnel are presented together with the temperature rise of the ambient air calculated from the extinction coefficient. A rise of 8.65 degrees K was obtained at 0.65. Mach, for an ambient temperature of 20 degrees C and relative humidity 49 percent, which is consistent with previous non-optical measurements.

Potter, Jason; Tatam, Ralph P.

1997-11-01

161

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

162

Evidence for a Critical Velocity in a Bose-Einstein Condensed Gas  

Microsoft Academic Search

We have studied dissipation in a Bose-Einstein condensed gas by moving a blue detuned laser beam through the condensate at different velocities. Strong heating was observed only above a critical velocity.

C. Raman; M. Köhl; R. Onofrio; D. S. Durfee; C. E. Kuklewicz; Z. Hadzibabic; W. Ketterle

1999-01-01

163

Boundary layers for the nonlinear discrete Boltzmann equation: Condensing vapor flow in the presence of a non-condensable gas  

NASA Astrophysics Data System (ADS)

Half-space problems for the Boltzmann equation are of great importance in the study of the asymptotic behavior of the solutions of boundary value problems of the Boltzmann equation for small Knudsen numbers. Half-space problems provide the boundary conditions for the fluid-dynamic-type equations and Knudsen-layer corrections to the solution of the fluid-dynamic-type equations in a neighborhood of the boundary. Here we consider a half-space problem of condensation for a pure vapor in the presence of a non-condensable gas by using discrete velocity models (DVMs) of the Boltzmann equation. The Boltzmann equation can be approximated by DVMs up to any order, and these DVMs can be applied for numerical methods, but also for mathematical studies to bring deeper understanding and new ideas. For one-dimensional half-space problems, the discrete Boltzmann equation (the general DVM) reduces to a system of ODEs. We obtain that the number of parameters to be specified in the boundary conditions depends on whether the condensing vapor flow is subsonic or supersonic. This behavior has earlier been found numerically. We want to stress that our results are valid for any finite number of velocities. This is an extension of known results for single-component gases (and for binary mixtures of two vapors) to the case when a non-condensable gas is present. The vapor is assumed to tend to an assigned Maxwellian, with a flow velocity towards the condensed phase, at infinity, while the non-condensable gas tends to zero at infinity. Steady condensation of the vapor takes place at the condensed phase, which is held at a constant temperature. We assume that the vapor is completely absorbed, that the non-condensable gas is diffusively reflected at the condensed phase, and that vapor molecules leaving the condensed phase are distributed according to a given distribution. The conditions, on the given distribution at the condensed phase, needed for the existence of a unique solution of the problem are investigated, assuming that the given distribution at the condensed phase is sufficiently close to the Maxwellian at infinity and that the total mass of the non-condensable gas is sufficiently small. Exact solutions and solvability conditions are found for a specific simplified discrete velocity model (with few velocities).

Bernhoff, N.

2012-11-01

164

Microstructural investigations of rapidly solidified Cu-Nb alloy powders produced by inert-gas atomization. Technical report  

SciTech Connect

This study presents a metallographic technique which enables the microstructural examination of the cross-sections of individual, fine-scale (10-75 um) powder particles. The technique was developed to permit characterization of the as-solidified features of Cu-based powders produced by high pressure inert gas atomization in order to relate the microstructures to processing history. In order to perform the necessary microscopy to elucidate the microstructural features, a metallographic technique was developed to permit characterization of the as-atomized microstructures within the individual powder particles. This technique involved classifying, mounting, and polishing through the diameters of individual powder particles and then using an attack etch to remove some of the copper matrix. This enabled characterization of the niobium-rich second phase. Secondary electron imaging on a scanning electron microscope provided the necessary resolution to characterize the second phase morphologies as a function powder-particle size, ultimately relating the microstructures to processing conditions.

Zeik, K.L.; Anderson, I.E.; Koss, D.A.; Howell, P.R.

1991-04-30

165

Possible robust insulator-superconductor transition on solid inert gas and other substrates  

NASA Astrophysics Data System (ADS)

We present observations of the insulator-superconductor transition in ultrathin films of Bi on amorphous quartz, quartz coated with Ge, and solid xenon condensed on quartz. The relative permeability ?r ranges from 1.5 for Xe to 15 for Ge. Though we find screening effects as expected, the I-S transition is robust, and unmodified by the substrate. The resistance separatrix is found to be close to h/4e2 and the crossover thickness close to 25 Å for all substrates. I-V studies and Aslamazov-Larkin analyses indicate superconductivity is inhomogeneous. The transition can be understood in terms of a percolation model.

Das Gupta, K.; Sambandamurthy, G.; Soman, Swati S.; Chandrasekhar, N.

2001-03-01

166

Robust Insulator-Superconductor transition on solid inert gas and other substrates  

NASA Astrophysics Data System (ADS)

We present observations of the insulator-superconductor transition in ultrathin films of Bi on amorphous quartz, quartz coated with Ge, and for the first time, solid xenon condensed on quartz. The relative permeability ?r ranges from 1.5 for Xe to 15 for Ge. Though we find screening effects as expected, the I-S transition is robust, and unmodified by the substrate. The resistance separatrix is found to be close to h/4e^2 and the crossover thickness close to 25 Åfor all substrates. I-V studies and Aslamazov-Larkin analyses indicate superconductivity is inhomogeneous. The transition can be understood in terms of a percolation model.

Sambandamurthy, G.; Das Gupta, K.; Soman, Swati; Chandrasekhar, N.

2001-03-01

167

Turbulent noncondensing and condensing gas jets in liquids  

NASA Astrophysics Data System (ADS)

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

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

1985-08-01

168

Momentum and heat transfer of an inert gas jet to the melt in laser cutting  

Microsoft Academic Search

The forces exerted by the gas jet on the molten layer in laser cutting are investigated theoretically by solving the equations of motion of the gas flow. The pressure distribution along the cutting front is found by the method of conformal mapping, while frictional forces are obtained from boundary layer theory. Both the pressure gradient and the frictional force are

M. Vicanek; G. Simon

1987-01-01

169

Onset of thermal ripples at the interface of an evaporating liquid under a flow of inert gas  

NASA Astrophysics Data System (ADS)

The dynamics of thermal ripples at the interface of a volatile pure liquid (C2H5OH) is studied experimentally and numerically. Liquid evaporates under a flow of inert gas (N2) circulating along the interface. The evaporation rate is varied by regulating both the gas flow rate and the gas pressure. Experiments in microgravity environment allowed to identify a transition to "interfacial turbulence," along which some particular events such as nearly periodic and possible intermittent behaviors. Direct numerical simulations have been performed, and compare qualitatively well with experimental results, offering new insights into the physical mechanisms involved. Small-scale ripples appear to arise from a secondary instability of large-scale convection cells and their motion seems to follow the corresponding large-scale surface flow. The relative role of surface tension and buoyancy in triggering these flows is assessed by comparing experiments and simulations in both microgravity and ground conditions. Qualitative features compare satisfactorily well such as typical speed and orientation of the thermal ripples, as well as spiral flow in the bulk.

Scheid, B.; Margerit, J.; Iorio, C. S.; Joannes, L.; Heraud, M.; Queeckers, P.; Dauby, P. C.; Colinet, P.

2012-05-01

170

Nucleation and growth of Nb nanoclusters during plasma gas condensation  

NASA Astrophysics Data System (ADS)

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.; DeCerbo, J. N.

2013-06-01

171

Structure and size distribution of silicon nanocrystals prepared by pulsed laser ablation in inert background gas  

Microsoft Academic Search

Silicon nanocrystals have been synthesized using pulsed laser ablation in argon background gas. The morphology structure and the size distribution of the silicon nanocrystals depending on the background gas pressure (0.1 Pa-100 Pa) have been studied. Experiment results show that the morphology of the silicon nanograins transits from amorphous-like continuous thin film to dispersed nanocrystals with the decreasing of argon

Guangsheng Fu; Wei Yu; Huijing Du; Li Han

2001-01-01

172

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

SciTech Connect

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

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

1982-09-27

173

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

174

Effect of post-weld aging treatment on mechanical properties of Tungsten Inert Gas welded low thickness 7075 aluminium alloy joints  

Microsoft Academic Search

This paper reports the influence of post-weld aging treatment on the microstructure, tensile strength, hardness and Charpy impact energy of weld joints low thickness 7075 T6 aluminium alloy welded by Tungsten Inert Gas (TIG). Hot cracking occurs in aluminium welds when high levels of thermal stress and solidification shrinkage are present while the weld is undergoing various degrees of solidification.

M. Temmar; M. Hadji; T. Sahraoui

2011-01-01

175

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

Microsoft Academic Search

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

Liming Liu; Gang Song; Guoli Liang; Jifeng Wang

2005-01-01

176

Observation of the trapping of radioactive inert gas radon on oxide glass surfaces: Macroporous scintillating-glass-fiber bundle alpha detector  

Microsoft Academic Search

We report the observation of the trapping of radioactive inert gas radon (222Rn) on oxide glass under ambient air temperature and pressure of 300 K and 760 Torr, respectively. Radon diffuses from the source, through two macroporous scintillating-glass-fiber bundle alpha detectors in series, to the end of the linear closed system filled with ambient air. The strategy is to provide

I. S. Kim; A. Appleby; G. H. Sigel Jr.

1997-01-01

177

Heat transfer performances of a thermosyphon contained non-condensible gas (1)  

NASA Astrophysics Data System (ADS)

The heat transfer performances of the thermosiphon contained non-condensible gas with the working fluid were obtained by an experimental study. The relations among the heat transfer rate, the effectively working length of condenser, the temperature difference between the evaporator and the condenser, and the over-all heat transfer coefficient are described.

Kaneko, K.; Negishi, K.

1985-03-01

178

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

Code of Federal Regulations, 2010 CFR

...2009-07-01 2009-07-01 false Inerting, enriching, and diluting systems...Vapor Control Systems § 154.824 Inerting, enriching, and diluting systems. (a) A vapor control system which uses inerting, enriching, or diluting gas must...

2009-07-01

179

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

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Inerting, enriching, and diluting systems...Vapor Control Systems § 154.824 Inerting, enriching, and diluting systems. (a) A vapor control system which uses inerting, enriching, or diluting gas must...

2010-07-01

180

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

SciTech Connect

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

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

2005-05-15

181

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

182

Fatigue strength of tungsten inert gas-repaired weld joints in airplane critical structures  

Microsoft Academic Search

In this work the effect of Gas Tungsten Arc Welding (GTAW) repairs on the axial fatigue strength of an AISI 4130 steel welded joint used in airframe critical to the flight-safety was investigated. Fatigue tests were performed at room temperature on 0.89mm thick hot-rolled plates with constant amplitude and load ratio of R=0.1, at 20Hz frequency. Monotonic tensile tests, optical

Marcelino P. Nascimento; Herman J. C. Voorwald; João da C. Payão Filho

2011-01-01

183

Natural gas conversion in a fluidized bed with an inert separable heat transfer agent  

Microsoft Academic Search

1.Experiments on the conversion of natural gas on a pilot plant which reproduces the process completely have shown that a high conversion level is possible. The residual methane content is 0.4–0.8% vol. for a specific crude supply rate of 3000–5000 cm3\\/g · h.2.It has been shown that a highly efficient separation of the catalyst from the heat transfer agent is

A. R. Brun-Tsekhovoi; Ya. R. K. Atsobashvili; V. F. Varnavskii; A. M. Glukhomanyuk; V. G. Kul'bachnyi; K. E. Makhorin

1969-01-01

184

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

185

Quantum hydrodynamics in dilute-gas Bose-Einstein condensates  

NASA Astrophysics Data System (ADS)

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

Engels, Peter

2012-10-01

186

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

SciTech Connect

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

Murakami, Tomoyuki; Okuno, Yoshihiro [Department of Energy Sciences, Tokyo Institute of Technology, 4259-G3-38 Nagatsuta, Midori-ku, Yokohama 226-8502 (Japan)

2008-07-28

187

Scaling and Thermodynamics of a Trapped Bose-Condensed Gas  

NASA Astrophysics Data System (ADS)

We investigate the thermodynamics of a Bose gas interacting with repulsive forces and confined in a harmonic trap. We show that the relevant parameters of the system (temperature, number N of atoms, harmonic oscillator length, deformation of the trap, s-wave scattering length) fix its thermodynamic behavior in the large N limit through two dimensionless scaling parameters. These are the reduced temperature t = T/T0c and the ratio ? between the T = 0 value of the chemical potential, evaluated in the Thomas-Fermi limit, and the critical temperature T0c of the noninteracting model. The scaling functions relative to the condensate fraction, energy, chemical potential, and moment of inertia are calculated within the Popov approximation.

Giorgini, S.; Pitaevskii, L. P.; Stringari, S.

1997-05-01

188

Final Report on the Field Operation of a High Efficiency Condensing Gas Furnace.  

National Technical Information Service (NTIS)

The Ontario Ministry of Municipal Affairs and Housing and the Consumers' Gas Company Ltd. share a mutual interest in the performance, reliability and acceptability of the new market entry models of energy-efficient condensing residential-sized gas furnace...

1983-01-01

189

A gas gun for plane and shear loading of inert and explosive targets  

NASA Astrophysics Data System (ADS)

The design and construction of a 75 mm bore laboratory gas gun capable of velocities up to 500 m s-1 is described. The performance of the gun is compared with the analytical interior ballistics model of Pidduck and Kent [A. E. Seigel, Report No. AGARDograph 91 (1965)]. The gun is constructed for two idealized loading geometries. One is plate impact, in which the loading is in one-dimensional strain, accomplished by impacting plane impactors onto targets aligned to micron tolerances, precisely normal to the impact axis. Another is pressure-shear in which the target and impacting plate are angled, but still aligned to the same tolerances. The system requires flexibility for addressing the problem of reactive targets when design must allow complete detonation of the target (up to 250 g). This has been accomplished and the system approved for use by the appropriate authorities.

Bourne, N. K.; Stevens, G. S.

2001-04-01

190

RESERVOIR ANALYSIS AND RECOVERY PREDICTION FOR CYCLING GAS-CONDENSATE RESERVOIRS  

Microsoft Academic Search

This paper demonstrates techniques for determining gas reserves and for predicting performance of gas- condensate reservoirs where cycling is employed. Calculation of original gas in place is accomplished through the application of a simple transient gas energy balance equation. The volumetric gas balance utilizes past production data and bottomhole pressures taken over the life of the project. Reservoir and fluid

O. R. Butterfield; J. D. Clark; E. B. Brauer

1965-01-01

191

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

Microsoft Academic Search

Two of the largest gas fields in the world, Hasi R'Mel, Algeria and North Dome, Qatar, also contain substantial condensate and light oil reserves. Gas to source rock geochemical correlation is difficult due to the paucity of molecular parameters in the former although stable isotope composition is invaluable. However, by correlating source rocks with light oils and condensates associated with

J. E. Zumberge; S. Macko

1996-01-01

192

Removal of fine particles in wet flue gas desulfurization system by heterogeneous condensation  

Microsoft Academic Search

A novel process to remove fine particles with high efficiency by heterogeneous condensation in a wet flue gas desulfurization (WFGD) system is presented. A supersaturated vapor phase, necessary for condensational growth of fine particles, was achieved in the SO2 absorption zone and at the top of the wet FGD scrubber by adding steam in the gas inlet and above the

Linjun Yang; Jingjing Bao; Jinpei Yan; Jinhui Liu; Shijuan Song; Fengxian Fan

2010-01-01

193

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

SciTech Connect

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

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

2010-07-15

194

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

NASA Astrophysics Data System (ADS)

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

Murakami, Tomoyuki; Okuno, Yoshihiro

2009-03-01

195

Inert gas cutting of titanium sheet with pulsed mode CO2 laser  

NASA Astrophysics Data System (ADS)

The present work aimed at studying the dynamic behavior of melt ejection in laser cutting of 1 mm thick titanium sheet and to obtain dross-free cuts with minimum heat affected zone (HAZ). CO2 laser cutting of titanium sheet was carried out with continuous wave (CW) and pulsed mode laser operation with different shear gases namely argon, helium and nitrogen. Laser cutting with high frequency and low-duty cycle pulse mode operation produced dross-free cuts with no noticeable HAZ. Helium, because of its high heat convection and ability to generate high shear stress, produced laser-cuts with narrow HAZ and low dross, as compared to those produced with argon as the shear gas. Microscopic features of laser cut surfaces were analyzed and correlated with dynamic mechanism involved in laser cutting process. Process parameters for laser piercing, required for the initiation of fusion cut within the sheet, were also studied. Laser piercing requires either CW or high-duty cycle (>80%) pulse mode operation.

Rao, B. Tirumala; Kaul, Rakesh; Tiwari, Pragya; Nath, A. K.

2005-12-01

196

46 CFR 153.923 - Inerting systems.  

Code of Federal Regulations, 2010 CFR

... Shipping 5 2010-10-01 2010-10-01 false Inerting systems. 153.923 Section 153.923 Shipping COAST...Operations General Cargo Operational Requirements § 153.923 Inerting systems. The master shall ensure that the inert gas...

2010-10-01

197

46 CFR 153.923 - Inerting systems.  

Code of Federal Regulations, 2011 CFR

... Shipping 5 2011-10-01 2011-10-01 false Inerting systems. 153.923 Section 153.923 Shipping COAST...Operations General Cargo Operational Requirements § 153.923 Inerting systems. The master shall ensure that the inert gas...

2011-10-01

198

46 CFR 153.923 - Inerting systems.  

Code of Federal Regulations, 2010 CFR

... Shipping 5 2009-10-01 2009-10-01 false Inerting systems. 153.923 Section 153.923 Shipping COAST...Operations General Cargo Operational Requirements § 153.923 Inerting systems. The master shall ensure that the inert gas...

2009-10-01

199

46 CFR 153.923 - Inerting systems.  

Code of Federal Regulations, 2012 CFR

... Shipping 5 2012-10-01 2012-10-01 false Inerting systems. 153.923 Section 153.923 Shipping COAST...Operations General Cargo Operational Requirements § 153.923 Inerting systems. The master shall ensure that the inert gas...

2012-10-01

200

Non-condensible gas injection including alpha-olefin sulfonate surfactant additives  

SciTech Connect

This patent describes a non-condensible gas process of recovering hydrocarbons from a subterranean formation in the absence of steam, wherein the formation is penetrated by at least one injection well and at least one production well. The process consists of: (a) injecting a non-condensible gas at an injection well until non-condensible gas breakthrough occurs at a production well; (b) continuing to inject into the formation the non-condensible gas and, including therewith and under non-stream conditions, a sufficient amount of alpha-olefin sulfonate to form a non-condensible gas and alpha-olefin sulfonate foam to assist the movement of hydrocarbons toward the production well; and (c) recovering hydrocarbons from the production well.

Duerksen, J.H.; Wall, R.G.; Knight, J.D.

1986-02-25

201

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

NASA Astrophysics Data System (ADS)

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

Baker, Colin C.

202

Effects of TiO 2 coating on the microstructures and mechanical properties of tungsten inert gas welded AZ31 magnesium alloy joints  

Microsoft Academic Search

The effects of TiO2 coating on the macro-morphologies, microstructures and mechanical properties of tungsten inert gas (TIG) welded AZ31 magnesium alloy joints were investigated by microstructural observations, microhardness tests and tensile tests. The results showed that an increase in the amount of the TiO2 coating resulted in an increase in the weld penetration and the depth\\/width (D\\/W) ratio of the

Linzhi Wang; Jun Shen; Nan Xu

2011-01-01

203

Brazability of dissimilar metals tungsten inert gas butt welding–brazing between aluminum alloy and stainless steel with Al–Cu filler metal  

Microsoft Academic Search

Dissimilar metals tungsten inert gas butt welding–brazing between 5A06 aluminum alloy and SUS321 stainless steel was carried out using Al–Cu6 filler metal and non-corrosive flux. A thin intermetallic compound layer has formed in welded seam\\/steel interface and the average thickness of the whole layer is 3–5?m, which is less than the limited value of 10?m. The intermetallic compound layer consists

S. B. Lin; J. L. Song; C. L. Yang; C. L. Fan; D. W. Zhang

2010-01-01

204

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

Microsoft Academic Search

In this paper, the effects of heat input on the microstructures and mechanical properties of tungsten inert gas arc butt-welded AZ61 magnesium alloy plates were investigated by microstructural observations, microhardness tests and tensile tests. The results show that with an increase of the heat input, the grains both in the fusion zone and the heat-affected zone coarsen and the width

Dong Min; Jun Shen; Shiqiang Lai; Jie Chen

2009-01-01

205

Experimental investigation of the anode region of a free-burning atmospheric-pressure inert-gas arc I. General characteristics of the discharge. Low-current regime  

Microsoft Academic Search

This paper reports the experimental investigation of the anode region of a free-burning inert-gas arc at atmospheric pressure\\u000a in the current range from a few amperes to hundreds of amperes. The tungsten thermionic-emission cathode and the large-diameter\\u000a water-cooled copper anode that were used permitted the anode arc root to assume its natural form. The general characteristics\\u000a of the discharge are

G. A. Dyuzhev; N. K. Mitrofanov; S. M. Shkol’nik

1997-01-01

206

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

207

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

208

Bose-Einstein condensation in a gas of sodium atoms  

Microsoft Academic Search

We have observed Bose-Einstein condensation of sodium atoms. The atoms were trapped in a novel trap that employed both magnetic and optical forces. Evaporative cooling increased the phase-space density by 6 orders of magnitude within seven seconds. Condensates contained up to 5 x 105 atoms at densities exceeding 1014 cm-3. The striking signature of Bose condensation was the sudden appearance

K. B. Davis; M. O. Mewes; M. R. Andrews; Druten van N. J; D. S. Durfee; D. M. Kurn; W. Ketterle

1995-01-01

209

Isobaric Inert Gas Counterdiffusion.  

National Technical Information Service (NTIS)

There were 32 participants at this workshop representing various scientific disciplines, federal agencies and universities all with an interest in diving medicine. Session I which dealt with experiments and observations, presented not only an historical r...

M. B. Kent

1982-01-01

210

The physics of trapped dilute-gas Bose–Einstein condensates  

Microsoft Academic Search

The experimental realisation of Bose–Einstein condensates of dilute atomic vapours has generated immense interest and activity in this field. Here, we present a review of recent theoretical research into the properties of trapped dilute-gas Bose–Einstein condensates. Topics covered include ground-state properties of trapped condensates, elementary excitations, light scattering properties, tests of broken gauge symmetry, and the atom laser.

A. S. Parkins; D. F. Walls

1998-01-01

211

Crossover from a Bose-Einstein Condensate of Molecules to a Degenerate Fermi Gas of Atoms  

Microsoft Academic Search

We have observed Bose-Einstein condensation of molecules. When a spin mixture of fermionic ^6Li atoms was evaporatively cooled in an optical dipole trap near a Feshbach resonance, the atomic gas was converted into ^6Li2 molecules. Below 600 nK, a Bose-Einstein condensate of up to 900,000 molecules was identified by the sudden onset of a bimodal density distribution. This condensate realizes

Christian H. Schunck; Sebastian M. F. Raupach; Martin W. Zwierlein; Claudiu A. Stan; Andrew J. Kerman; Subhadeep Gupta; Zoran Hadzibabic; Wolfgang Ketterle

2004-01-01

212

Corrosion of muffler materials in automotive exhaust gas condensates  

SciTech Connect

The corrosion of automotive mufflers collected in North America was investigated. Aluminum (Al)-plated steels corroded severely in the substrate under the Al plating. Type 409 (UNS S40900) stainless steels sustained a large number of pits. The effects of ions in the condensate and activated carbon on the corrosion resistance of muffler materials were studied with a newly developed condensate corrosion test.

Ujiro, Takumi; Kitazawa, Makoto; Togashi, Fusao (Kawasaki Steel Corp., Chiba (Japan). Iron and Steel Research Lab.)

1994-12-01

213

Corrosion of muffler materials in automotive exhaust gas condensates  

Microsoft Academic Search

The corrosion of automotive mufflers collected in North America was investigated. Aluminum (Al)-plated steels corroded severely in the substrate under the Al plating. Type 409 (UNS S40900) stainless steels sustained a large number of pits. The effects of ions in the condensate and activated carbon on the corrosion resistance of muffler materials were studied with a newly developed condensate corrosion

Takumi Ujiro; Makoto Kitazawa; Fusao Togashi

1994-01-01

214

Structural-group composition of organosulphur compounds of gas condensate from the Urtabulak deposit of Uzbekistan  

SciTech Connect

Concentrates of organosulphur compounds were isolated for the first time from the gas condensates of the Urtabulak deposit by extraction using 87 and 91% sulphuric acid. The structural-group composition of sulphides and thiophenes in the condensate were examined. The sulphides among the organosulphur compounds consist mainly of thiamono-, thiabicyclo-paraffins and dialkylsulphides. The thiophenes include alkylsubstituted thiophenes and benzothiophenes.

Agadzhanova, N.V.; Aliyeva, R.B.; Lyapina, N.K.; Parfenova, M.A.; Shmakov, V.S.

1983-01-01

215

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

216

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

Code of Federal Regulations, 2013 CFR

...pipe diameters from the gas injection point. (g) Oxygen analyzers which operate at elevated temperatures (i.e. , zirconia oxide or thermomagnetic) must not be used. (h) An inerting system must: (1) Supply sufficient inert gas to...

2013-07-01

217

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

218

EVALUATION OF THE TUNGSTEN-INERT GAS-ARC WELDING PROCESS FOR JOINING TYPE 6061T-6 ALUMINUM TUBING  

Microsoft Academic Search

The use of the tungsten inert-arc Process for joining aluminum tubing ; was investigated. The welds were requlred to be leak tight, smooth and ; metallurgically sound in relation to the base metal. The materials and ; procedures used are described. It was coucluded that welds could be made to meet ; all the requirements except that drop-through on the

Kittle

1958-01-01

219

Pair Condensation in a Finite Trapped Fermi Gas  

NASA Astrophysics Data System (ADS)

Cold atomic fermi gases are widely studied examples of strongly interacting quantum systems. Examples include ^40K, ^6Li and neutron matter. In the unitary regime, where the scattering length is very large compared to the mean inter-particle distance, they are nonperturbative and exhibit universal behavior. Moreover, they can be created in the lab, providing an excellent testing ground for theory. In this talk I will describe quantum Monte Carlo calculations we have been performing to study the signatures of pairing and the superfluid phase transtion in finite-size systems. Using the Auxillary Field Monte Carlo (AFMC) method, we study the pairing gap, condensate fraction, pair wavefunction and density profile as a function of temperature. Defining the onset of condensation Tcond as the temperature when the condensate fraction crosses its (finite) noninteracting limit, we consider the question of whether pairing occurs prior to condensation in the unitary regime.

Gilbreth, Christopher; Alhassid, Yoram

2012-02-01

220

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

221

Free electron in compressed inert gases  

SciTech Connect

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

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

2008-08-15

222

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

223

Bose-Einstein-condensation temperature of a gas of weakly dissociated diatomic molecules  

SciTech Connect

We consider the properties of a gas of bosonic diatomic molecules in the limit when few of the molecules are dissociated. Taking into account the effects of dissociation and scattering among molecules and atoms, we calculate the dispersion relation for a molecule, and the thermal depletion of the condensate. We calculate the dependence of the Bose-Einstein-condensation (BEC) temperature of a uniform gas on the atom-atom scattering length, and conclude that, for a broad Feshbach resonance, the condensation temperature increases as the molecular state becomes less strongly bound, thereby giving rise to a maximum in the transition temperature in the BEC-BCS crossover. We also argue on general grounds that, for a gas in a harmonic trap and for a narrow Feshbach resonance, the condensation temperature will decrease with increasing scattering length.

Jensen, L. M.; Maekelae, H.; Pethick, C. J. [Department of Physics, Nanoscience Center, University of Jyvaeskylae, P. O. Box 35, FI-40014 Jyvaeskylae (Finland); Department of Physics, University of Turku, FI-20014 Turku (Finland); Nordita, Blegdamsvej 17, DK-2100 Copenhagen O (Denmark)

2007-03-15

224

Optimization of quality characteristics parameters in a pulsed metal inert gas welding process using grey-based Taguchi method  

Microsoft Academic Search

Optimization of a manufacturing process has to take into accounts all of the factors that influence the product quality and\\u000a productivity. Optimization of welding process parameters is considerably complex because welding is a multi-variable process,\\u000a which is influenced by a lot of process uncertainties. In this paper, a grey-based Taguchi method has been adopted to optimize\\u000a the pulsed metal inert

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

2009-01-01

225

Effect of non-condensable gas on the vapor flow in thermosiphons  

NASA Astrophysics Data System (ADS)

A detailed flow field survey was conducted to get a better insight into condensation mechanism of vapor flow onto the cooled plate in the enclosure. A two-dimensional thermosyphon was used as an experimental apparatus and special attention was paid to the effect of non-condensable gas in the thermosiphon. Generally it is understood that the non-condensable gas in the thermosiphon in its steady state operation occupies an upper region of the condensation section, and that there exists an interfacial layer separating vapor flow from non-condensable gas which will move vertically according to the heat input rate applied to the thermosiphon. However the structural properties of this interfacial layer and the boundary layer on the wall of condensation section, such as location of layers, thickness, temperature or density variation across them, have not been thoroughly investigated. A real time laser holographic interferometer was used to visualize a flow field in the thermosiphon. Temperature distribution was measured to evaluate the total heat transfer coefficient in the condensation section.

Matsumoto, T.; Kobayashi, Y.

1985-03-01

226

The role of causality in tunable Fermi gas condensates  

NASA Astrophysics Data System (ADS)

We develop a new formalism for the description of the condensates of cold Fermi atoms whose speed of sound can be tuned with the aid of a narrow Feshbach resonance. We use this to look for spontaneous phonon creation that mimics spontaneous particle creation in curved space-time in Friedmann-Robertson-Walker and other model universes.

Hsiang, Jen-Tsung; Lin, Chi-Yong; Lee, Da-Shin; Rivers, Ray J.

2013-10-01

227

The role of causality in tunable Fermi gas condensates.  

PubMed

We develop a new formalism for the description of the condensates of cold Fermi atoms whose speed of sound can be tuned with the aid of a narrow Feshbach resonance. We use this to look for spontaneous phonon creation that mimics spontaneous particle creation in curved space-time in Friedmann-Robertson-Walker and other model universes. PMID:24025481

Hsiang, Jen-Tsung; Lin, Chi-Yong; Lee, Da-Shin; Rivers, Ray J

2013-09-11

228

A Carbon Dioxide Gas Turbine Direct Cycle with Partial Condensation for Nuclear Reactors  

Microsoft Academic Search

A carbon dioxide gas turbine power generation system with a partial condensation cycle has been proposed for thermal and fast nuclear reactors, in which compression is done partly in the liquid phase and partly in the gas phase. This cycle achieves higher cycle efficiency than a He direct cycle mainly due to reduced compressor work of the liquid phase and

Yasuyoshi Kato; Takeshi Nitawaki; Yoshio Yoshizawa

2002-01-01

229

Borate Ions in the Gas Phase, Fast-Atom Bombardment of Condensed-Phase Borates.  

National Technical Information Service (NTIS)

The intractable properties of crystalline and vitreous, condensed-phase boron-oxygen compounds have always hindered the generation and analysis of gas-phase boron-oxygen species. Recently, structures of gas-phase boron oxide cations, generated by fast-ato...

R. J. Doyle

1988-01-01

230

Kinetic limit of the ethane and ethylene yield in the gas phase condensation of methane  

SciTech Connect

A kinetic simulation of the initiated oxidative condensation of methane in the gas phase showed that the additional generation of methyl radicals via the reaction CH{sub 4} + O{sub 2} {yields} CH{sub 3} + HO{sub 2} causes a nearly tenfold increase in the C{sub 2} hydrocarbon yield. However, a kinetic limit of the yield exists that is close to that determined in experiments on the catalytic oxidative condensation of methane.

Vedeneev, V.I.; Arutyunov, V.S.; Basevich, V.Ya. [N.N. Semenov Institute of Chemical Physics, Moscow (Russian Federation)

1995-08-01

231

Manifestation of superfluidity in an evolving Bose-Einstein condensed gas.  

PubMed

We study the generation of excitations due to an "impurity" (static perturbation) placed into an oscillating Bose-Einstein condensed gas in the time-dependent trapping field. It is shown that there are two regions for the position of the local perturbation. In the first region the condensate flows around the impurity without generation of excitations demonstrating superfluid properties. In the second region the creation of excitations occurs, at least within a limited time interval, revealing destruction of superfluidity. The phenomenon can be studied by measuring the damping of condensate oscillations at different positions of the impurity. PMID:11019270

Kagan, Y; Maksimov, L A

2000-10-01

232

Interpretation of results from well testing gas-condensate reservoirs: Comparison of theory and field cases  

SciTech Connect

A more complete understanding of well test interpretation results for gas-condensate fields may depend significantly on the availability of sufficient, accurate and specific field correlations involving fluid and rock properties, and on flow meter surveys. Apart from compositional variations, the most useful parameters in reviewing gas-condensate samples are condensate-gas ratio, dewpoint pressure and gas gravity. Pressure data recorded by quartz crystal gauges can result in gas gradients with sufficient accuracy to confirm variations in gas composition with depth for a reservoir of several hundred metres in thickness. By comparing these gradients with gas gravities from fluid samples, variation of the initial dewpoint pressure with depth was established. Special core analysis was carried out/sup +/ to obtain specific high velocity ..beta..-factors. However, when these laboratory measurements are compared with results obtained from production test analysis, large discrepancies are found in most cases, which can be attributed to multiphase flow near the wellbore. Although wellstream composition is found to be a function of rate, the presence of a stable condensate bank appears to be unfounded.

Behrenbruch, P.; Kozma, G.

1984-09-01

233

The condensation of ideal Bose gas in a gravitational field  

NASA Astrophysics Data System (ADS)

Bose-Einstein condensation of two- and three-dimensional boson gases confined in the one-dimensional gravitational field is investigated. Using the semiclassical approximation method, the expressions for the BEC transition temperature, condensate fraction, heat capacity and the entropy of the system are obtained. The heat capacities of the systems with D=1, 2, 3 (D is the dimension) at the critical temperature are discussed. We find that for the 1-D and 2-D boson systems, the heat capacities are continuous, but for the 3-D case there is a gap at the critical temperature Tc. The entropies of the systems with D=1, 2, 3 are also studied in detail. It is found that the entropies increase with the increasing of the temperature T.

Du, Cong-Fei; Li, Hong; Lin, Zhen-Quan; Kong, Xiang-Mu

2012-11-01

234

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

NASA Astrophysics Data System (ADS)

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

Liang, Yongbin; Che, Defu; Kang, Yanbin

2007-05-01

235

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

236

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

NASA Astrophysics Data System (ADS)

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

Bourg, S.; Péron, F.; Lacquement, J.

2007-01-01

237

Prediction of the phase state of a natural condensed gas mixture  

SciTech Connect

The authors have examined how the type of data on the fractional composition of debutanized gas condensate and the selection of a state equation can influence the prediction of the phase state of a natural condensed gas mixture. The authors have attempted to have the fractional composition of the mixture as found by single-pass evaporation approach that revealed by fractional distillation. The advantage of the vacancy quasichemical equation of states over the Redlich-Kwong-Soave equation in the calculation of phase equilibria has been shown.

Kuranov, G.L.; Pukinskii, I.B.; Smirnova, N.A.; Avdeev, D.Yu. [St. Petersburg State Univ. (Russian Federation)

1995-07-20

238

On the retrograde condensation behavior of lean natural gas  

SciTech Connect

The occurrence of liquid dropout in natural gas pipelines may cause operational problems during storage, transport, and processing. Therefore, the availability of a model that accurately predicts the amount of liquid formed is of grate importance for the natural gas industry. The objective of this study is to develop a thermodynamic model for the accurate prediction of the amount of liquid formed in natural gas pipelines at transportation conditions. As input, the model requires an accurate gas analysis. A modified Peng-Robinson equation of state was selected for the phase equilibrium calculations. Interaction parameters were optimized from experimental data at conditions of practical interest, i.e., at pressures 10gas like methane and nitrogen. Also, an extensive experimental program was carried out to study the influence of minute amounts of nitrogen, ethane and carbon dioxide in methane on the solubility behavior of decane in these gas mixtures. From a sensitivity analysis, it could be concluded that the liquid dropout is influenced mainly by the concentration and characterization of C{sub 7}-C{sub 13} fractions. In this work, two characterization procedures to represent these fractions are compared. For two types of lean natural gas, the model predictions are compared with field measurement data, recently supplied by the Dutch natural gas industry.

Voulgaris, M.E.; Peters, C.J.; Arons, J. Swaan de [Univ. of Technology, Julianalaan (Netherlands)

1995-05-01

239

On the retrograde condensation behavior of lean natural gas  

NASA Astrophysics Data System (ADS)

The occurrence of liquid dropout in natural gas pipelines may cause operational problems during storage, transport, and processing. Therefore, the availability of a model that accurately predicts the amount of liquid formed is of great importance for the natural gas industry. The objective of this study is to develop a thermodynamic model for the accurate prediction of the amount of liquid formed in natural gas pipelines at transportation conditions. As input, the model requires an accurate gas analysis. A modified Peng-Robinson equation of state was selected for the phase equilibrium calculations. Interaction parameters were optimized from experimental data at conditions of practical interest, i.e., at pressures 10 < p < 70 bar and at temperatures 250 < T < 290 K. For a number of “keysystems,” the interaction parameters were calculated from new accurate solubility data of heavy hydrocarbons in some of the main constituents of natural gas like methane and nitrogen. Also, an extensive experimental program was carried out to study the influence of minute amounts of nitrogen, ethane and carbon dioxide in methane on the solubility behavior of decane in these gas mixtures. From a sensitivity analysis, it could be concluded that the liquid dropout is influenced mainly by the concentration and characterization of C7-C13 fractions. In this work, two characterization procedures to represent these fractions are compared. For two types of lean natural gas, the model predictions are compared with field measurement data, recently supplied by the Dutch natural gas industry.

Voulgaris, M. E.; Peters, C. J.; de Swaan Arons, J.

1995-05-01

240

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

241

Continuous Measurement of Multiple Inert and Respiratory Gas Exchange in an Anaesthetic Breathing System by Continuous Indirect Calorimetry  

Microsoft Academic Search

A method was tested which permits continuous monitoring from a breathing system of the rate of uptake of multiple gas species,\\u000a such as occurs in patients during inhalational anaesthesia. The method is an indirect calorimetry technique which uses fresh\\u000a gas rotameters for control, regulation and measurement of the gas flows into the system, with continuous sampling of mixed\\u000a exhaust gas,

Christopher Stuart-Andrews; Philip Peyton; Craig Humphries; Gavin Robinson; Brian Lithgow

2009-01-01

242

Condensate statistics and thermodynamics of weakly interacting Bose gas: Recursion relation approach  

NASA Astrophysics Data System (ADS)

We study condensate statistics and thermodynamics of weakly interacting Bose gas with a fixed total number N of particles in a cubic box. We find the exact recursion relation for the canonical ensemble partition function. Using this relation, we calculate the distribution function of condensate particles for N=200. We also calculate the distribution function based on multinomial expansion of the characteristic function. Similar to the ideal gas, both approaches give exact statistical moments for all temperatures in the framework of Bogoliubov model. We compare them with the results of unconstraint canonical ensemble quasiparticle formalism and the hybrid master equation approach. The present recursion relation can be used for any external potential and boundary conditions. We investigate the temperature dependence of the first few statistical moments of condensate fluctuations as well as thermodynamic potentials and heat capacity analytically and numerically in the whole temperature range.

Dorfman, K. E.; Kim, M.; Svidzinsky, A. A.

2011-03-01

243

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 1.5wt.% 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

2013-07-30

244

Effect of Inert Gas Additive Species on Cl(2) High Density Plasma Etching of Compound Semiconductors: Part 1. GaAs and GaSb  

SciTech Connect

The role of the inert gas additive (He, Ar, Xe) to C12 Inductively Coupled Plasmas for dry etching of GaAs and GaSb was examined through the effect on etch rate, surface roughness and near-surface stoichiometry. The etch rates for both materials go through a maximum with Clz 0/0 in each type of discharge (C12/'He, C12/Ar, C12/Xc), reflecting the need to have efficient ion-assisted resorption of the etch products. Etch yields initially increase strongly with source power as the chlorine neutral density increases, but decrease again at high powers as the etching becomes reactant-limited. The etched surfaces are generally smoother with Ax or Xe addition, and maintain their stoichiometry.

Abernathy, C.R.; Cho, H.; Hahn, Y.B.; Hays, D.C.; Jung, K.B.; Pearton, S.J.; Shul, R.J.

1998-12-23

245

Tungsten oxide nanoparticles grown by condensation in gas using domestic appliances  

Microsoft Academic Search

We report on the preparation of WO3 nanostructures using tungsten wire and iron wool in a domestic microwave oven. Pure WO3 nanoparticles were octahedral or rhombohedral while iron containing nanoparticles were spheroidal. Nanoparticles of monoclinic and cubic WO3 were found in the interior of burned commercial light bulbs, where they grow by a spontaneous reactive gas condensation process. This process

V. M. Fuenzalida; D. G. Galvez-Arancibia; I. J. Olavarria-Contreras; M. A. Salinger-Basterrica; D. E. Diaz-Droguett

2011-01-01

246

The simulator TOUGH2\\/EWASG for modelling geothermal reservoirs with brines and non-condensible gas  

Microsoft Academic Search

An equation-of-state (EOS) module has been developed for the TOUGH2 simulator, belonging to the MULKOM family of computer codes developed at Lawrence Berkeley National Laboratory. This module, named EWASG (Equation-of-State for Water, Salt and Gas), is able to handle three-component mixtures of water, sodium chloride, and a slightly soluble non-condensible gas (NCG). At present the NCG can be chosen to

Alfredo Battistelli; Claudio Calore; Karsten Pruess

1997-01-01

247

Chemistry with weakly-coordinating fluorinated alkoxyaluminate anions: Gas phase cations in condensed phases?  

Microsoft Academic Search

Many very simple and fundamentally important cations were initially observed in the gas phase, e.g. inside a mass spectrometer or even in space. The question arises, how to stabilize and study these gas phase cations in condensed phases. In this review, our work on the use of weakly-coordinating anions (WCAs) of type [Al(ORF)4]? and [(RFO)3Al–F–Al(ORF)3]? to investigate structural and chemical

Ingo Krossing; Andreas Reisinger

2006-01-01

248

Bose Einstein condensation of a relativistic q-deformed Bose gas  

Microsoft Academic Search

The q-deformed Bose-Einstein distribution derived from the q-boson algebra is used to study the low-temperature behavior of an ideal q-deformed Bose gas with relativistic energy spectrum. The effects of q-deformation on the properties relative to Bose-Einstein condensation (BEC) are discussed. It is shown that q-deformation leads to some novel characteristics different from those of an original Bose gas, which include

Guozhen Su; Shukuan Cai; Jincan Chen

2008-01-01

249

Bose-Einstein Condensation of a q-DEFORMED Bose Gas in a Random Box  

Microsoft Academic Search

The q-deformed Bose-Einstein distribution is used to study the Bose-Einstein condensation (BEC) of a q-deformed Bose gas in random box. It is shown that the BEC transition temperature is lowered due to random boundary conditions. The effects of q-deformation on the properties of the system are also discussed. We find some properties of a q-deformed Bose gas, which are different

Ying Wang; Xiang-Mu Kong

2010-01-01

250

Preparation of gas hydrates by nonequilibrium condensation of molecular beams  

NASA Astrophysics Data System (ADS)

Layers of amorphous ice saturated with carbon dioxide were prepared by the deposition of molecular beams of water and gas onto a substrate cooled with liquid nitrogen. Their heating is accompanied by glass transition (softening) and subsequent spontaneous crystallization. The glass transition and crystallization temperatures were determined from the change in dielectric properties during heating. The heat effects of the transformations were detected using differential thermal analysis. The crystallization of amorphous layers under conditions of deep metastability leads to the formation of crystalline hydrates. The avalanche nucleation of crystallization sites captures the gas molecules; therefore, they are not displaced by the movement of the crystallization front.

Faizullin, M. Z.; Vinogradov, A. V.; Koverda, V. P.

2013-09-01

251

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

252

Methanol Droplet Combustion in Oxygen-Inert Environments in Microgravity.  

National Technical Information Service (NTIS)

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. ...

D. L. Dietrich F. A. Williams M. C. Hicks V. Nayagam

2013-01-01

253

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

254

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

255

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

SciTech Connect

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

Astrakharchik, G.E. [Dipartimento di Fisica and BEC-INFM, Universita di Trento, I-38050 Povo (Italy); Institute of Spectroscopy, 142190 Troitsk (Russian Federation); Boronat, J.; Casulleras, J. [Departament de Fisica i Enginyeria Nuclear, Campus Nord B4-B5, Universitat Politecnica de Catalunya, E-08034 Barcelona (Spain); Giorgini, S. [JILA, University of Colorado, Boulder, Colorado 80309-0440 (United States); Dipartimento di Fisica and BEC-INFM, Universita di Trento, I-38050 Povo (Italy)

2005-12-02

256

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

2008-08-08

257

Shock waves in a one-dimensional Bose gas: From a Bose-Einstein condensate to a Tonks gas  

SciTech Connect

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

Damski, Bogdan [Theory Division, Los Alamos National Laboratory, MS-B213, Los Alamos, New Mexico 87545 (United States)

2006-04-15

258

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

NASA Astrophysics Data System (ADS)

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

Kumar, Viren

259

Bose-Einstein Condensation of a q-DEFORMED Bose Gas in a Random Box  

NASA Astrophysics Data System (ADS)

The q-deformed Bose-Einstein distribution is used to study the Bose-Einstein condensation (BEC) of a q-deformed Bose gas in random box. It is shown that the BEC transition temperature is lowered due to random boundary conditions. The effects of q-deformation on the properties of the system are also discussed. We find some properties of a q-deformed Bose gas, which are different from those of an ordinary Bose gas. Similar results are also shown for q-bosons confined in a harmonic oscillator potential well.

Wang, Ying; Kong, Xiang-Mu

260

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

SciTech Connect

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

Natu, Stefan S.; Mueller, Erich J. [Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853 (United States)

2011-11-15

261

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

PubMed

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

Moustafa, N E

262

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.

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

2011-01-01

263

Collective Excitations of a Trapped Bose-Condensed Gas  

NASA Astrophysics Data System (ADS)

We investigate the low energy excitations of a dilute atomic Bose gas confined in a harmonic trap of frequency ?0 and interacting with repulsive forces. The dispersion law ? = ?0\\(2n2+2nl+3n+l\\)1/2 for the elementary excitations is obtained for large numbers of atoms in the trap, to be compared with the prediction ? = ?0\\(2n+l\\) of the noninteracting harmonic oscillator model. Here n is the number of radial nodes and l is the orbital angular momentum. The effects of the kinetic energy pressure are estimated using a sum rule approach. Results are also presented for deformed traps and attractive forces.

Stringari, S.

1996-09-01

264

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

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

265

Condensed Fraction of an Atomic Bose Gas Induced by Critical Correlations  

NASA Astrophysics Data System (ADS)

We study the condensed fraction of a harmonically trapped atomic Bose gas at the critical point predicted by mean-field theory. The nonzero condensed fraction f0 is induced by critical correlations which increase the transition temperature Tc above TcMF. Unlike the Tc shift in a trapped gas, f0 is sensitive only to the critical behavior in the quasiuniform part of the cloud near the trap center. To leading order in the interaction parameter a/?0, where a is the s-wave scattering length and ?0 the thermal wavelength, we expect a universal scaling f0?(a/?0)4. We experimentally verify this scaling using a Feshbach resonance to tune a/?0. Further, using the local density approximation, we compare our measurements with the universal result obtained from Monte Carlo simulations for a uniform system, and find excellent quantitative agreement.

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

2011-11-01

266

Study of materials to resist corrosion in condensing gas fired furnaces  

NASA Astrophysics Data System (ADS)

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

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

1981-02-01

267

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

PubMed

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

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

2013-08-26

268

Crossover from a Molecular Bose-Einstein Condensate to a Degenerate Fermi Gas  

Microsoft Academic Search

We demonstrate a reversible conversion of a 6Li2 molecular Bose-Einstein condensate to a degenerate Fermi gas of atoms by adiabatically crossing a Feshbach resonance. By optical in situ imaging, we observe a smooth change of the cloud size in the crossover regime. On the Feshbach resonance, the ensemble is strongly interacting and the measured cloud size is 75(7)% of the

M. Bartenstein; A. Altmeyer; S. Riedl; S. Jochim; C. Chin; J. Hecker Denschlag; R. Grimm

2004-01-01

269

Evidence of Bose-Einstein Condensation in an Atomic Gas with Attractive Interactions  

Microsoft Academic Search

Evidence for Bose-Einstein condensation of a gas of spin-polarized ⁷Li atoms is reported. Atoms confined to a permanent-magnet trap are laser cooled to 200 μK and are then evaporatively cooled to lower temperatures. Phase-space densities consistent with quantum degeneracy are measured for temperatures in the range of 100 to 400 nK. At these high phase-space densities, diffraction of a probe

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

1995-01-01

270

Diamondoid Hydrocarbons—Application in the Chemical Fingerprinting of Natural Gas Condensate and Gasoline  

Microsoft Academic Search

Diamondoids are a class of naturally occurring, saturated hydrocarbons in petroleum that consist of three or more fused cyclohexane rings, which results in a “diamond-like” structure. The diamondoids that can be found in light petroleum liquids (e.g., natural gas condensates), intermediate petroleum distillates (e.g., naphthas), and finished petroleum products (e.g., automotive gasoline) include adamantane (boiling point ? 190°C) and diamantane

Scott A. Stout; Gregory S. Douglas

2004-01-01

271

Expansion of a Fermi gas interacting with a Bose-Einstein condensate.  

PubMed

We study the expansion of an atomic Fermi gas interacting attractively with a Bose-Einstein condensate. We observe a slower evolution of the radial-to-axial aspect ratio which reveals the importance of the mutual attraction between the two samples during the first phase of the expansion. For large atom numbers, we also observe a bimodal momentum distribution of the Fermi gas, which reflects the spatial distribution of the mixture in trap. This effect allows us to extract important information on the overlap of the two species across the collapse. PMID:15089523

Ferlaino, F; De Mirandes, E; Roati, G; Modugno, G; Inguscio, M

2004-04-09

272

Mesoscopic effects in Bose-Einstein condensate fluctuations of a weakly interacting gas in a box  

NASA Astrophysics Data System (ADS)

I study the quantum and thermal fluctuations of the Bose-Einstein condensate (BEC) in a box with the periodic boundary conditions under a particle-number constraint. I start with the particle-number conserving operator formalism of Girardeau and Arnowitt. I employ an expansion of the distribution function in terms of the multinomial coefficients. I present analytical formulas and numerical calculations for the central moments of the ground state occupation fluctuations in an weakly interacting Bose gas in a box with a mesoscopic number of particles in the framework of the Bogoliubov approximation. I discuss the mesoscopic effects in statistics of a weakly interacting gas versus statistics in the thermodynamic limit and statistics of an ideal gas. I emphasize the non-Gaussian nature of the BEC fluctuations. The crossover relations between the fluctuations of weakly interacting Bose gas and ideal Bose gas are obtained. In particular, high and low temperature asymptotics are presented. Suppression of the condensate fluctuations at the moderate temperatures and their enhancement at very low temperatures are described.

Dorfman, Konstantin

2008-10-01

273

Origin of the gas-condensate deposits and prediction of the phase state of hydrocarbons in northern West Siberia  

SciTech Connect

In northern West Siberia, a zone of petroleum accumulation has been identified, embracing the Nadym-Pur, Pur-Tazovskiy, Gydanovsk, and Yamal' petroliferous regions. A characteristic feature of this zone is the development of a thick (up to 2000 m) Cretaceous complex, with which the bulk of the gas and gas-condensate resources of West Siberia is associated. The origin of the gas-condensate deposits, discovered over a wide range from Upper Cretaceous (Cenomanian) to Jurassic, with differing hydrocarbon composition and amount of condensate, has been inadequately investigated, but nevertheless it has great significance in predicting the phase state of the hydrocarbons in the deposits and the reliability of estimating the reserves. The paper discusses the origin of these gas condensates from petroleum and coal deposits. 5 references.

Nemchenko, N.N.; Rovenskaya, A.S.

1987-05-01

274

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

275

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

NASA Astrophysics Data System (ADS)

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.

2011-09-01

276

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

NASA Astrophysics Data System (ADS)

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

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

2005-08-01

277

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

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

278

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

NASA Astrophysics Data System (ADS)

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

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

2012-11-01

279

Investigation of the vapor-gas front boundary in the condenser of a flat-plate gas-regulated heat pipe  

Microsoft Academic Search

A mathematical model is developed for vapor flow in the condenser of a flat-plate gas-regulated heat pipe at a uniform condensation rate. The equations of momentum and mass conservation are solved by the Karman-Pohlhausen method, and velocity profiles are calculated for the Re range of 0.0001-4.18. The results indicate that reverse flows occur in the condensers of such heat pipes.

V. V. Galaktionov; A. A. Parfenteva; V. D. Portnov; V. Ia. Sasin

1982-01-01

280

Laboratory and Field Evaluation of the Controlled Condensation System for S03 Measurements in Flue Gas Streams  

Microsoft Academic Search

The study reported by this paper involves the use of the Controlled Condensation System (Goksoyr\\/Ross Coil) for flue gas S03 measurements in both the laboratory and the field, under low and high mass loadings. The Controlled Condensation System cools the flue gas to below the dewpoint of H2S04 but above the H20 dewpoint. The resulting aerosol is collected either on

Ray F. Maddalone; Steve F. Newton; Richard G. Rhudy; Robert M. Statnick

1979-01-01

281

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

DOEpatents

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

Mohr, Charles M. (Idaho Falls, ID); Mines, Gregory L. (Idaho Falls, ID); Bloomfield, K. Kit (Idaho Falls, ID)

2002-01-01

282

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

NASA Astrophysics Data System (ADS)

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

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

2007-07-01

283

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

PubMed

Despite a rapid expansion over the past decade in the reliance on intrinsic bioremediation to remediate petroleum hydrocarbon plumes in groundwater, significant research gaps remain. Although it has been demonstrated that bacterial sulfate reduction can be a key electron accepting process in many petroleum plumes, little is known about the rate of this reduction process in plumes derived from crude oil and gas condensates at cold-climate sites (mean temperature <10 degrees C), and in complex hydrogeological settings such as silt/clay aquitards. In this field study, sulfate was injected into groundwater contaminated by gas condensate plumes at two petroleum sites in Alberta, Canada to enhance in-situ bioremediation. In both cases the groundwater near the water table had low temperature (6-9 degrees C). Monitoring data had provided strong evidence that bacterial sulfate reduction was a key terminal electron accepting process (TEAP) in the natural attenuation of dissolved hydrocarbons at these sites. At each site, water with approximately 2000 mg/L sulfate and a bromide tracer was injected into a low-sulfate zone within a condensate-contaminant plume. Monitoring data collected over several months yielded conservative estimates for sulfate reduction rates based on zero-order kinetics (4-6 mg/L per day) or first-order kinetics (0.003 and 0.01 day(-1)). These results favor the applicability of in-situ bioremediation techniques in this region, under natural conditions or with enhancement via sulfate injection. PMID:17292997

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

2007-01-13

284

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

285

Bose–Einstein condensation of a relativistic Bose gas in a harmonic potential  

NASA Astrophysics Data System (ADS)

Using semiclassical method, Bose–Einstein condensation (BEC) of a relativistic ideal Bose gas (RIBG) with and without antibosons in the three-dimensional (3D) harmonic potential is investigated. Analytical expressions for the BEC transition temperature, condensate fraction, specific heat and entropy of the system are obtained. Relativistic effects on the properties of the system are discussed and it is found that the relativistic effect decreases the transition temperature Tc but enlarges the gap of specific heat at Tc. We also study the influence of antibosons on a RIBG. Comparing with the system without antibosons, the system with antibosons has a higher transition temperature and a lower Helmholtz free energy. It implies that the system with antibosons is more stable.

Du, Cong-Fei; Kong, Xiang-Mu

2012-06-01

286

The electronic structure of gas phase croconic acid compared to the condensed phase: More insight into the hydrogen bond interaction  

NASA Astrophysics Data System (ADS)

The electronic structure of croconic acid in the gas phase has been investigated by means of core level and valence band photoemission spectroscopy and compared with hybrid Heyd-Scuseria-Ernzerhof density functional theory calculations. The results have been compared with the corresponding ones of the condensed phase. In the gas phase, due to the absence of hydrogen bond intermolecular interactions, the O 1 s core level spectrum shows a shift of binding energy between the hydroxyl (O-H) and the carbonyl group (C=O) of 2.1 eV, which is larger than the condensed phase value of 1.6 eV. Interestingly, such a shift decreases exponentially with the increase of the O-H distance calculated from theory. The significant differences between the gas and condensed phase valence band spectra highlight the important role played by the hydrogen bonding in shaping the electronic structure of the condensed phase.

Bisti, F.; Stroppa, A.; Perrozzi, F.; Donarelli, M.; Picozzi, S.; Coreno, M.; de Simone, M.; Prince, K. C.; Ottaviano, L.

2013-01-01

287

Condensation of N bosons: Microscopic approach to fluctuations in an interacting Bose gas  

SciTech Connect

We present a microscopic derivation of the master equation for the condensate density matrix for an interacting Bogoliubov-Bose gas of N atoms. We choose the interaction Hamiltonian in a special way that substantially simplifies the master equation, yielding no coupling between diagonal and off-diagonal terms. The present formulation allows us to solve the problem analytically in a steady state and obtain the expression for the distribution function and equilibrium condensate fluctuations. For the first two central moments, our results are equivalent to those obtained in the canonical-ensemble quasiparticle formalism [V. V. Kocharovsky, Vl. V. Kocharovsky, and M. O. Scully, Phys. Rev. Lett. 84, 2306 (2000); Phys. Rev. A 61, 053606 (2000)], in the low-temperature range where these papers are valid, but also give an accurate description at high temperatures. The present analysis for an interacting Bose gas is as accurate as the master equation approach of Kocharovsky et al.[Phys. Rev. A 61, 023609 (2000)] is for an ideal gas.

Svidzinsky, Anatoly A.; Scully, Marlan O. [Texas A and M University, College Station, Texas 77843 (United States) and Princeton University, Princeton, New Jersey 08544 (United States)

2010-12-15

288

Vortices in atomic Bose-Einstein condensates in the large-gas-parameter region  

NASA Astrophysics Data System (ADS)

In this work we compare the results of the Gross-Pitaevskii and modified Gross-Pitaevskii equations with ab initio variational Monte Carlo calculations for Bose-Einstein condensates of atoms in axially symmetric traps. We examine both the ground state and excited states having a vortex line along the z axis at high values of the gas parameter and demonstrate an excellent agreement between the modified Gross-Pitaevskii and ab initio Monte Carlo methods, both for the ground and vortex states.

Nilsen, J. K.; Mur-Petit, J.; Guilleumas, M.; Hjorth-Jensen, M.; Polls, A.

2005-05-01

289

Three-body recombination of a condensed Bose gas near a Feshbach resonance  

SciTech Connect

In this paper, we study the three-body recombination rate of a homogeneous dilute Bose gas with a Feshbach resonance at zero temperature. The ground state and excitations of this system are obtained. The three-body recombination in the ground state is due to the breakup of an atom pair in the quantum depletion and the formation of a molecule by an atom from the broken pair and an atom from the condensate. The rate of this process is in good agreement with the experiment on {sup 23}Na in a wide range of magnetic fields.

Zhang Yingyi; Yin Lan [School of Physics, Peking University, Beijing 100871 (China)

2005-10-15

290

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

PubMed

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

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

1996-01-01

291

Theory of Bose-Einstein condensation in a microwave-driven interacting magnon gas.  

PubMed

Room temperature Bose-Einstein condensation (BEC) of magnons in YIG films under microwave driving has been recently reported. We present a theory for the interacting magnon gas driven out of equilibrium that provides rigorous support for the formation of the BEC. The theory relies on the cooperative mechanisms created by the nonlinear magnetic interactions and explains the spontaneous generation of quantum coherence and magnetic dynamic order when the microwave driving power exceeds a critical value. The results fit very well the experimental data for the intensity and the decay rate of Brillouin light scattering and for the microwave emission from the BEC as a function of driving power. PMID:21386417

Rezende, Sergio M

2010-03-30

292

Synthesis of FeCu Nanopowder by Levitational Gas Condensation Process  

NASA Astrophysics Data System (ADS)

Condensation from the vapor state is an important technique for the preparation of nanopowders. Levitational gas condensation is one such technique that has a unique ability of attaining steady state. Here, we present the results of applying this technique to an iron-copper alloy (96Fe-4Cu). A qualitative model of the process is proposed to understand the process and the characteristics of resultant powder. A phase diagram of the alloy system in the liquid-vapor region was calculated to help understand the course of condensation, especially partitioning and coring during processing. The phase diagram could not explain coring in view of the simultaneous occurrence of solidification and the fast homogenization through diffusion in the nanoparticles; however, it could predict the very low levels of copper observed in the levitated drop. The enrichment of copper observed near the surface of the powder was considered to be a manifestation of the lower surface energy of copper compared with that of iron. Heat transfer calculations indicated that most condensed particles can undergo solidification even when they are still in the proximity of the levitated drop. It helped us to predict the temperature and the cooling rate of the powder particles as they move away from the levitated drop. The particles formed by the process seem to be single domain, single crystals that are magnetic in nature. They, thus, can agglomerate by forming a chain-like structure, which manifests as a three-dimensional network enclosing a large unoccupied space, as noticed in scanning electron microscopy and transmission electron microscopy studies. This also explains the observed low packing density of the nanopowders.

Sivaprahasam, Duraisamy; Sriramamurthy, A. M.; Vijayakumar, M.; Sundararajan, G.; Chattopadhyay, Kamanio

2010-08-01

293

Bose Einstein condensation of a relativistic q-deformed Bose gas  

NASA Astrophysics Data System (ADS)

The q-deformed Bose-Einstein distribution derived from the q-boson algebra is used to study the low-temperature behavior of an ideal q-deformed Bose gas with relativistic energy spectrum. The effects of q-deformation on the properties relative to Bose-Einstein condensation (BEC) are discussed. It is shown that q-deformation leads to some novel characteristics different from those of an original Bose gas, which include the criteria on the occurrence of BEC, critical temperature and jump of heat capacity at the critical point. The results obtained here provide a unified description for the properties of q-deformed Bose systems from the nonrelativistic case to the ultrarelativistic limit, so that some important conclusions in the literature are included in this paper.

Su, Guozhen; Cai, Shukuan; Chen, Jincan

2008-02-01

294

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

SciTech Connect

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

Marcos Dantus

2008-09-23

295

Monodisperse, submicrometer droplets via condensation of microfluidic-generated gas bubbles.  

PubMed

Microfluidics (MFs) can produce monodisperse droplets with precise size control. However, the synthesis of monodisperse droplets much smaller than the minimum feature size of the microfluidic device (MFD) remains challenging, thus limiting the production of submicrometer droplets. To overcome the minimum micrometer-scale droplet sizes that can be generated using typical MFDs, the droplet material is heated above its boiling point (bp), and then MFs is used to produce monodisperse micrometer-scale bubbles (MBs) that are easily formed in the size regime where standard MFDs have excellent size control. After MBs are formed, they are cooled, condensing into dramatically smaller droplets that are beyond the size limit achievable using the original MFD, with a size decrease corresponding to the density difference between the gas and liquid phases of the droplet material. Herein, it is shown experimentally that monodisperse, submicrometer droplets of predictable sizes can be condensed from a monodisperse population of MBs as generated by MFs. Using perfluoropentane (PFP) as a representative solvent due to its low bp (29.2 °C), it is demonstrated that monodisperse PFP MBs can be produced at MFD temperatures >3.6 °C above the bp of PFP over a wide range of sizes (i.e., diameters from 2 to 200 ?m). Independent of initial size, the generated MBs shrink rapidly in size from about 3 to 0 °C above the bp of PFP, corresponding to a phase change from gas to liquid, after which they shrink more slowly to form fully condensed droplets with diameters 5.0 ± 0.1 times smaller than the initial size of the MBs, even in the submicrometer size regime. This new method is versatile and flexible, and may be applied to any type of low-bp solvent for the manufacture of different submicrometer droplets for which precisely controlled dimensions are required. PMID:22700364

Seo, Minseok; Matsuura, Naomi

2012-06-15

296

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

297

Frequency and damping of hydrodynamic modes in a trapped Bose-condensed gas  

SciTech Connect

Recently it was shown that the Landau-Khalatnikov two-fluid hydrodynamics describes the collision-dominated region of a trapped Bose condensate interacting with a thermal cloud. We use these equations to discuss the low frequency hydrodynamic collective modes in a trapped Bose gas at finite temperatures. We derive variational expressions based on these equations for both the frequency and damping of collective modes. A new feature is our use of frequency-dependent transport coefficients, which produce a natural cutoff by eliminating the collisionless low-density tail of the thermal cloud. Above the superfluid transition, our expression for the damping in trapped inhomogeneous gases is analogous to the result first obtained by Landau and Lifshitz for uniform classical fluids. We also use the moment method to discuss the crossover from the collisionless to the hydrodynamic region. Recent data for the monopole-quadrupole mode in the hydrodynamic region of a trapped gas of metastable {sup 4}He is discussed. We also present calculations for the damping of the analogous m=0 monopole-quadrupole condensate mode in the superfluid phase.

Nikuni, Tetsuro; Griffin, Allan [Department of Physics, Faculty of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo, 162-9601 (Japan); Department of Physics, University of Toronto, Toronto, Ontario, M5S 1A7 (Canada)

2004-02-01

298

Geology of the Smoerbukk field - A gas-condensate fault trap  

SciTech Connect

The Smoerbukk field, which was discovered offshore mid-Norway in 1984, is a large gas-condensate find located on Haltenbanken in the western part of the Halten Terrace. The field covers an area of 140 km{sup 2}, and straddles Blocks 6506/11 and 6506/12. Water depth is 250-300 m. The field contains four reservoirs that consist of Lower and Middle Jurassic sandstones deposited in shallow-marine tidally influenced nearshore and braid-delta front environments. Structurally, the Smoerbukk field is defined as a southeasterly dipping structure with major normal faults to the west and north. Three wells have been drilled, proving reserves in reservoirs with different hydrocarbon contacts and GORs. Reservoir properties vary considerably mainly due to diagenetic effects caused by burial depth. Sedimentology and sequence stratigraphy are considered to be important tools to predict lateral variations in reservoir facies. At present, total in-place reserves are estimated to be 106 G Sm{sup 3} (3.7 tcf) gas and 90 M Sm{sup 3} (566 tcf) of condensate/oil.

Ehrenberg, S.N.; Gjerstad, H.M.; Hadler-Jacobson, F. (Statoil A.S., Stavanger (Norway))

1990-09-01

299

?-DIMENSIONAL Ideal Quantum q-GAS:. Bose-Einstein Condensation and ?-POINT Transition  

NASA Astrophysics Data System (ADS)

We consider an ideal quantum q-gas in ? spatial dimensions and energy spectrum ?i? p? Departing from the Hamiltonian H=?[N], we study the effect of the deformation on thermodynamic functions and equation of state of that system. The virial expansion is obtained for the high temperature (or low density) regime. The critical temperature is higher than in non-deformed ideal gases. We show that Bose-Einstein condensation always exists (unless when ?/?=1) for finite q but not for q=?. Employing numerical calculations and selecting for v/? the values 3/2, 2 and 3, we show the critical temperature as a function of q, the specific heat CV and the chemical potential µ as functions of {T {T {Tcq }}} ; } {Tcq }} for q=1.05 and q=4.5. CV exhibits a ?-point discontinuity in all cases, instead of the cusp singularity found in the usual ideal gas. Our results indicate that physical systems which have quantum symmetries can exhibit Bose-Einstein condensation phenomenon, the critical temperature being favored by the deformation parameter.

R-Monteiro, M.; Roditi, Itzhak; Rodrigues, Ligia M. C. S.

300

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  

Microsoft Academic Search

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

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

2007-01-01

301

Design studies for direct contact condensers with and without the presence of noncondensible gas  

Microsoft Academic Search

Analytical models are presented to predict the condensation in film type direct contact condensation and related processes. The related processes include condensation on a thin film flowing over an isothermal vertical surface and condensation on tube bundles. In addition the effects of noncondensible gases on the above processes are examined. The analysis is based on conservation laws alone and does

Nadig

1984-01-01

302

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); Klingler, Kerry M. (Idaho Falls, ID); Wilding, Bruce M. (Idaho Falls, ID)

2010-02-23

303

Gaussian basis sets for accurate calculations on molecular systems in gas and condensed phases  

NASA Astrophysics Data System (ADS)

We present a library of Gaussian basis sets that has been specifically optimized to perform accurate molecular calculations based on density functional theory. It targets a wide range of chemical environments, including the gas phase, interfaces, and the condensed phase. These generally contracted basis sets, which include diffuse primitives, are obtained minimizing a linear combination of the total energy and the condition number of the overlap matrix for a set of molecules with respect to the exponents and contraction coefficients of the full basis. Typically, for a given accuracy in the total energy, significantly fewer basis functions are needed in this scheme than in the usual split valence scheme, leading to a speedup for systems where the computational cost is dominated by diagonalization. More importantly, binding energies of hydrogen bonded complexes are of similar quality as the ones obtained with augmented basis sets, i.e., have a small (down to 0.2 kcal/mol) basis set superposition error, and the monomers have dipoles within 0.1 D of the basis set limit. However, contrary to typical augmented basis sets, there are no near linear dependencies in the basis, so that the overlap matrix is always well conditioned, also, in the condensed phase. The basis can therefore be used in first principles molecular dynamics simulations and is well suited for linear scaling calculations.

Vandevondele, Joost; Hutter, Jürg

2007-09-01

304

Nanocrystalline BaTiO{sub 3} from gas-condensation process  

SciTech Connect

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

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

1996-12-31

305

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

SciTech Connect

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

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

1989-01-01

306

Roeggaskondensering med varmepumpe paa flisfyrede kedelanlaeg. (Condensing of steam in flue gas using a heat pump system in relation to a wood chip fired boiler).  

National Technical Information Service (NTIS)

The aim of this report is to describe existing methods for condensing steam water in flue gas in relation to combustion of forest biomass, and to describe the implementation of a plant for condensing of water in flue gas on an existing installation for co...

A. Evald B. Petersen C. Bisgaard G. Vogel

1989-01-01

307

Secondary ions produced from condensed rare gas targets under highly charged MeV\\/amu heavy ion bombardment  

Microsoft Academic Search

Secondary ions produced from condensed rare gas targets are observed under MeV\\/amu, highly charged, heavy ion impact. The intensities of the observed cluster ions decrease smoothly as the cluster sizes become large but show some discontinuities at particular sizes of cluster ions. This seems to be closely related to the stabilities of cluster ion structures. It is also noted that

H. Tawara; T. Tonuma; H. Kumagai; T. Matsuo

1994-01-01

308

Ethyl ferrocene in gas, condensed, or adsorbed phases: three types of photosensitive elements for use in gaseous detectors  

Microsoft Academic Search

We have investigated the properties of an organometallic compound, ethyl ferrocene (EF), which we propose to use as the photosensitive element in gaseous detectors, both in the gas (vapour) phase and, in condensed or adsorbed layers, as photocathodes. The big advantage of EF is that it is easy to handle, as it is not reactive to oxygen. The sensitivity for

G. Charpak; V. Peskov; F. Sauli; D. Scigocki

1989-01-01

309

The effect of condensable minor components on the gas separation performance of polymeric membranes for carbon dioxide capture  

Microsoft Academic Search

Polymeric membranes as a carbon dioxide capture technology have a number of advantages over other approaches, including their low cost, high performance separation, ease of synthesis, as well as mechanical and thermal stability. However, condensable components in flue gas, in particular water, undergo competitively adsorption with carbon dioxide within the membranes, resulting in a reduction in CO2 permeability. Furthermore, on

Colin A. Scholes; Sandra E. Kentish; Geoff W. Stevens

2009-01-01

310

Vapor–liquid equilibria of LNG and gas condensate mixtures by the Nasrifar–Moshfeghian equation of state  

Microsoft Academic Search

The Nasrifar–Moshfeghian (NM) equation of state (EOS) is used to predict vapor–liquid equilibria (VLE) of multi-component mixtures. The systems under study consist of liquefied natural gases (LNG), gas condensates, an asymmetric system, slightly polar systems and gas\\/water systems. van der Waals mixing rules are used and no pure component parameter is adjusted; however, the predictions compare well with experimental data,

Kh Nasrifar; M Moshfeghian

2002-01-01

311

Effects of Surface Water on the Adsorption of Inert Gases.  

National Technical Information Service (NTIS)

Molecular water on mildly outgassed open oxide surfaces can, under special circumstances, significantly reduce the monolayer capacity for inert gas molecules. Non-porous thoria and cubic europia are two examples. The special proviso is that the surface be...

R. B. Gammage H. F. Holmes

1976-01-01

312

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

313

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

NASA Astrophysics Data System (ADS)

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.; Kocharovsky, Vladimir V.

2010-03-01

314

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

315

Gas-Phase Condensation Reactions of SixOyHz- Oxyanions with H2O  

SciTech Connect

Water was reacted with gas-phase oxyanions having the general composition SixOyHz- that were formed and isolated in an ion trap-secondary ion mass spectrometer (IT-SIMS). The radical SiO2- reacted slowly with H2O to abstract HO, forming SiO3H-, at a rate of 8 × 10-13 cm3 molecule-1 s-1, corresponding to an efficiency of about 0.03% compared with the theoretical collision rate constant (average dipole orientation). The product ion SiO3H- underwent a consecutive condensation reaction with H2O to form SiO4H3- at a rate that was approximately 0.4-0.7% efficient. SiO4H3- did not undergo further reaction with water. The multiple reaction pathways by which radical SiO3- reacted with H2O were kinetically modeled using a stochastic approach. SiO3- reacted with water by three parallel reaction pathways: (1) abstraction of a radical H to form SiO3H-, which then reacted with a second H2O to form SiO4H3-; (2) abstraction of a radical OH to form SiO4H-, which further reacted by consecutive H abstractions to form SiO4H2- and then SiO4H3-; and (3) condensation with H2O to form SiO4H2-, which subsequently abstracted a radical H from a second H2O to form SiO4H3-. In all of these reactions, the rate constants were determined to be very slow, as determined by both direct measurement and stochastic modeling. For comparison, the even electron ion Si2O5H- was also investigated: it underwent condensation with H2O to form Si2O6H3-, with a rate constant corresponding to 50% efficiency. The reactions were also modeled using ab initio calculations at the UB3LYP/6-311+G(2d,p) level. Addition of H2O to SiO3-, SiO3H-, and Si2O5H- was calculated to be approximately 42, 45, and 55 kcal mol-1 exothermic, respectively, and encountered low activation barriers. Modeling of SiO2- and SiO3- reactions with H2O failed to produce radical abstraction reaction pathways observed in the IT-SIMS, possibly indicating that alternative reaction mechanisms are operative.

Groenewold, Gary Steven; Scott, Jill Rennee; Gianotto, Anita Kay; Hodges, Brittany DM; Kessinger, Glen Frank; Benson, Michael Timothy; Wright, J. B.

2001-09-01

316

Characterization of complex hydrocarbons in cigarette smoke condensate by gas chromatography–mass spectrometry and comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry  

Microsoft Academic Search

Gas chromatography–mass spectrometry with electron ionization and positive-ion chemical ionization and comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry (GC × GC–TOF-MS) were applied for the characterization of the chemical composition of complex hydrocarbons in the non-polar neutral fraction of cigarette smoke condensates. Automated data processing by TOF-MS software combined with structured chromatograms and manual review of library hits were used to

Xin Lu; Mingyue Zhao; Hongwei Kong; Junlan Cai; Jianfang Wu; Ming Wu; Ruixiang Hua; Jianfu Liu; Guowang Xu

2004-01-01

317

Coal pulverizer characteristics for inerting systems design  

SciTech Connect

Design of coal pulverizer inerting systems is dependent on reasonably precise knowledge of several operating parameters that are not available in the open literature. While oxygen concentration is used as the major criterion for an inerted pulverized coal (p.c.) system, the means for achieving acceptable O/sub 2/ concentrations in a full-scale operating p.c. system as a function of time is not well known. The purpose of this paper is to outline the analysis methods used to predict O/sub 2/ concentration in p.c. systems, and identify the fan curves and operating lines that allow this to be done. The results will be compared to tests on a full-scale operating p.c. system both steady-state and transient (master fuel trip, etc.), with steam inerting. The times required to reach acceptable O/sub 2/ concentration levels are noted along with identification of temperature, pressure and velocity histories in the p.c. system under test. The data suggest that significant steam condensation occurs in the system, which delays the reduction of O/sub 2/ concentration to final design level. The results will be discussed in light of the new NFPA safety standards now in use.

Cannon, J.N.; Germane, G.J.; Smoot, L.D.

1983-11-01

318

Process and apparatus for the treatment of moist gas-dust mixtures  

US Patent & Trademark Office Database

The invention relates to a process and an apparatus for the treatment of moist, explosive gas-dust mixtures, particularly coal dust mixtures in mill drying plants. To avoid a condensing out of residual moisture from intermediately stored dust, heated inert gas is supplied to the conveying system for the coal dust or the intermediate storage points.

1994-05-31

319

Mathematical simulation of natural gas condensation processes using the Peng-Robinson equation of state  

SciTech Connect

On the basis of its simplicity and the data obtained by a great number of tests and comparative analysis, the authors consider the Peng-Robinson (PR) equation of state to be the most suitable to calculate the condensation processes of natural gas, and further on to set up the equations of material and heat balances. In case of mixtures, the accuracy of the PR equation of state was mainly influenced by the correct selection of the interaction coefficients. The paper presents the calculation correlations of the thermal and thermodynamic properties published uncompletely before, as expressed with the parameters of the PR equation of state. Using the experiences obtained by the application of the PENG-ROBINSON AGA PROGRAM the authors have developed a module for calculation of phase equilibria and thermodynamic properties of fluid systems. This is the main module of their program MODEL-TECH (constructed in module structure) which is suitable to calculate separators, heat exchangers, heat sources, heat drains, Joule-Thomson effect, expansion turbines, compressors, detander-compressor units, arbitrary columns and simulation processes of any degree of complexity built from the above elements.

Nagy, Z.; Shirkovshiy, A.I.

1982-09-01

320

Automated Fire-Inerting System.  

National Technical Information Service (NTIS)

An automatic fire-inerting system utilizes a fire-inerting agent in an enclosed area to prevent a fire while allowing human habitability. The system comprises an analyzer for continuously monitoring the concentration of the agent and initiating a timed se...

R. G. Gann

1977-01-01

321

Influence of operation of Kh52 steel on corrosion processes in a model solution of gas condensate  

Microsoft Academic Search

We investigate the corrosion and electrochemical properties of Kh52 steel in the initial state and after 30 years of operation\\u000a in main gas pipelines. It is established that the behavior of the steel in a model medium of aqueous condensate is intensified\\u000a due to a high concentration of chloride depassivators. The corrosion rate is controlled by the diffusion of cathodic

O. T. Tsyrul’nyk; Z. V. Slobodyan; O. I. Zvirko; M. I. Hredil’; H. M. Nykyforchyn; G. Gabetta

2008-01-01

322

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

323

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

Microsoft Academic Search

A new equation-of-state module has been developed for;\\u000athe TOUGH2 simulator, belonging to the MULKOM;\\u000afamily of computer codes developed at LBL. This EOS;\\u000amodule is able to handle three-component mixtures of;\\u000awater, sodium chloride, and a non-condensible gas. It;\\u000acan describe liquid and gas phases, and includes;\\u000aprecipitation and dissolution of solid salt.;\\u000aThe dependence of density, viscosity, enthalpy,

A. Battistelli; C. Calore; K. Pruess

1993-01-01

324

Non-condensible gas injection including alpha-olefin sulfonate dimer surfactant additives and a process of stimulating hydrocarbon recovery from a subterranean formation  

SciTech Connect

A non-condensible gas process is described of recovering hydrocarbons from a subterranean formation in the absence of steam, wherein the formation is penetrated by at least one injection well and at least one production well. The process consists of: (a) injecting a non-condensible gas and, including therewith and in the absence of steam, a sufficient amount of an alpha-olefin sulfonate dimer to form a non-condensible gas and alpha-olefin sulfonate dimer foam at an injection well; (b) continuing to inject the non-condensible gas and alpha-olefin sulfonate dimer foam to assist the movement of hydrocarbons toward the production well, and (c) recovering hydrocarbons from a production well.

Duerksen, J.H.; Wall, R.G.; Knight, J.D.

1986-03-18

325

Modelling and simulation of acid gas condensation in an industrial chimney - article no. A39  

SciTech Connect

Coal power stations as well as waste incinerators produce humid acid gases which may condense in industrial chimneys. These condensates can cause corrosion of chimney internal cladding which is made of stainless steel, nickel base alloys or non metallic materials. In the aim of polluting emission reduction and material optimal choice, it is necessary to determine and characterize all the phenomena which occur throughout the chimney and more especially condensation and dissolution of acid gases (in this particular case, sulfur dioxide SO{sub 2}).

Serris, E.; Cournil, M.M.; Peultier, J. [Ecole des Mines de St Etienne, St Etienne (France)

2009-07-01

326

Acetone gas phase condensation on alkaline metals doped TiO 2 sol–gel catalysts  

Microsoft Academic Search

The vapor-phase condensation of acetone was studied over sol–gel prepared TiO2 and TiO2-doped with 1wt.% of Li+ or Rb+. The acetone condensation was catalyzed by basic sites and the obtained products were mesityl oxide (MO), isomesityl oxide (ISMO), mesitylene (M) as well as isophorone (IP) and phorone (P). The TiO2 crystalline structure was characterized by XRD and the basicity of

Marcial Zamora; Tessy López; Ricardo Gómez; Maximiliano Asomoza; Ruth Meléndrez

2005-01-01

327

Condensate Fraction in a 2D Bose Gas Measured across the Mott-Insulator Transition  

SciTech Connect

We realize a single-band 2D Bose-Hubbard system with Rb atoms in an optical lattice and measure the condensate fraction as a function of lattice depth, crossing from the superfluid to the Mott-insulating phase. We quantitatively identify the location of the superfluid to normal transition by observing when the condensed fraction vanishes. Our measurement agrees with recent quantum Monte Carlo calculations for a finite-sized 2D system to within experimental uncertainty.

Spielman, I. B.; Phillips, W. D.; Porto, J. V. [Joint Quantum Institute, National Institute of Standards and Technology, and University of Maryland, Gaithersburg, Maryland, 20899 (United States)

2008-03-28

328

Bose-Einstein condensation of photons in an ideal atomic gas  

NASA Astrophysics Data System (ADS)

We study peculiarities of Bose-Einstein condensation of photons that are in thermodynamic equilibrium with atoms of noninteracting gases. General equations of the thermodynamic equilibrium of the system under study are obtained. We examine solutions of these equations in the case of high temperatures, when the atomic components of the system can be considered as nondegenerated ideal gases of atoms, and the photonic component can form a state with the Bose condensate. Transcendental equation for transition temperature and expression for the density of condensed photons in the considered system are derived. We also obtain analytical solutions of the equation for the critical temperature in a number of particular cases. The existence of two regimes of Bose condensation of photons, which differ significantly in nature of transition temperature dependence on the total density of photons pumped into the system, is revealed. In one case, this dependence is a traditional fractional-power law, and in another one it is the logarithmic law. Applying numerical methods, we determine boundaries of existence and implementation conditions for different regimes of condensation depending on the physical parameters of the system under study. We also show that for a large range of physical systems that are in equilibrium with photons (from ultracold gases of alkali metals to certain types of ideal plasma), the condensation of photons should occur according to the logarithmic regime.

Kruchkov, Alex; Slyusarenko, Yurii

2013-07-01

329

Ethyl ferrocene in gas, condensed, or adsorbed phases: three types of photosensitive elements for use in gaseous detectors  

NASA Astrophysics Data System (ADS)

We have investigated the properties of an organometallic compound, ethyl ferrocene (EF), which we propose to use as the photosensitive element in gaseous detectors, both in the gas (vapour) phase and, in condensed or adsorbed layers, as photocathodes. The big advantage of EF is that it is easy to handle, as it is not reactive to oxygen. The sensitivity for the detection of BaF2 fast emission was measured with EF vapour and was found to be lower by a factor of close to 1.5 compared with TMAE vapour measured under the condition of full light absorption. Adsorbed or condensed layers of EF used as photocathodes in a gaseous detector achieved an efficiency that was lower by a factor of 4 to 10, depending on the experimental conditions.

Charpak, G.; Peskov, V.; Sauli, F.; Scigocki, D.

1989-05-01

330

Inerting of fine metallic powders  

Microsoft Academic Search

Minimum explosible concentration (MEC) tests were carried out on mixtures of 50:50 AI?Mg dust, AI dust, and 70:30 Mg?Ca dust. MgO dust was added to these mixtures as an inertant. The results indicate that between 70 and 75% fine MgO dust is required to completely inert the 50:50 AI?Mg dust, which is in the same range as the levels of

K. J. Mintz; M. J. Bray; D. J. Zuliani; P. R. Amyotte; M. J. Pegg

1996-01-01

331

Biodegradation of an alicyclic hydrocarbon by a sulfate-reducing enrichment from a gas condensate-contaminated aquifer.  

PubMed

We used ethylcyclopentane (ECP) as a model alicyclic hydrocarbon and investigated its metabolism by a sulfate-reducing bacterial enrichment obtained from a gas condensate-contaminated aquifer. The enrichment coupled the consumption of ECP with the stoichiometrically expected amount of sulfate reduced. During ECP biodegradation, we observed the transient accumulation of metabolite peaks by gas chromatography-mass spectrometry, three of which had identical mass spectrometry profiles. Mass-spectral similarities to analogous authentic standards allowed us to identify these metabolites as ethylcyclopentylsuccinic acids, ethylcyclopentylpropionic acid, ethylcyclopentylcarboxylic acid, and ethylsuccinic acid. Based on these findings, we propose a pathway for the degradation of this alicyclic hydrocarbon. Furthermore, a putative metabolite similar to ethylcyclopentylsuccinic acid was also found in samples of contaminated groundwater from the aquifer. However, no such finding was evident for samples collected from wells located upgradient of the gas condensate spill. Microbial community analysis of the ECP-degrading enrichment by denaturing gradient gel electrophoresis revealed the presence of at least three different organisms using universal eubacterial primers targeting 550 bp of the 16S rRNA gene. Based on sequence analysis, these organisms are phylogenetically related to the genera Syntrophobacter and Desulfotomaculum as well as a member of the Cytophaga-Flexibacter-Bacteroides group. The evidence suggests that alicyclic hydrocarbons such as ECP can be anaerobically activated by the addition to the double bond of fumarate to form alkylsuccinate derivatives under sulfate-reducing conditions and that the reaction occurs in the laboratory and in hydrocarbon-impacted environments. PMID:12514025

Rios-Hernandez, Luis A; Gieg, Lisa M; Suflita, Joseph M

2003-01-01

332

Crossover behavior in the phase transition of the Bose-Einstein condensation in a microwave-driven magnon gas  

SciTech Connect

A magnon gas in a film of yttrium iron garnet driven by microwave radiation exhibits Bose-Einstein condensation (BEC) when the driving power exceeds a critical value. We show that the nature and the critical exponents of the BEC transition change dramatically if the BEC magnons are significantly coupled to the zone-center magnons. The theoretical results explain the diverse behavior of the order parameter inferred from the experimental data for the light scattering and the microwave emission from the BEC observed with coherent and incoherent microwave pumping.

Rezende, Sergio M. [Departamento de Fisica, Universidade Federal de Pernambuco, Recife 50670-901, PE (Brazil)

2009-09-01

333

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

334

Novel Numerical Techniques to Calculate the Ground and Excited States of an Anisotropically Confined Condensed Bose Gas  

NASA Astrophysics Data System (ADS)

The ground and excited states of a weakly interacting, dilute Bose gas confined in a harmonic oscillator potential are studied using a number of novel computational techniques which enable the authors to extend previous results to the completely anisotropic well and to condensates which have been difficult or impossible to study previously. The numerical calculations employ a discrete variable representation (DVR) based on either the Hermite or LaGrange interpolating polynomials which make it trivial to evaluate matrix elements of the nonlinear term in the Hamiltonian and in addition, lead to a sparse matrix representation. We have found that standard iterative techniques applied to the solution of these non-linear partial differential equations, particularly for large number of condensate atoms, are non-convergent. This limitation has been overcome using a variant of the method of the Direct Inversion in the Iterated Subspace (DIIS) and a novel use of of the multi-grid technique. In addition, the sparse structure of the DVR representation enables the efficient application of iterative techniques such as the Davidson and/or Lanczos methods, to extract the relevant eigenpairs. The results are compared with recent experimental data obtained for Bose-condensed alkali metal vapours confined in magnetic traps.

Schneider, Barry I.; Feder, David L.

1998-05-01

335

Finite-temperature properties of dilute alkali gas Bose-Einstein condensates  

NASA Astrophysics Data System (ADS)

Zero-temperature mean field theory has given a good quantitative account(M. Edwards et al.), J. Res. Natl. Inst. Stand. Technol. 101, 553 (1996). of the observed properties of ``pure'' dilute Bose-Einstein condensates (BECs) that have been produced in 1995 and 1996 by ``shaving away'' the non-condensate population by forced evaporative cooling.(E. Cornell, J. Res. Natl. Inst. Stand. Technol. 101), 419 (1996). However, recent experiments at JILA and MIT have begun to explore finite-temperature phenomena, and an appropriate theoretical framework must be developed. We present calculations of the finite temperature properties of BECs in the JILA TOP trap, calculated within the Hartree-Fock-Bogoliubov and Popov approximations.(A. Griffin, Phys. Rev. B 53), 9341 (1996). We find the quantum depletion of the condensate at T=0 to be less than 1% for typical conditions of the JILA experiments. Results will be presented for the temperature dependence of condensate fraction and collective excitation frequencies within these approximations. The BEC Home Page regularly reports progress in this field.

Dodd, Robert J.; Burnett, Keith; Edwards, Mark; Clark, Charles W.

1997-03-01

336

Observation of Superfluid Flow in a Bose-Einstein Condensed Gas  

Microsoft Academic Search

We have studied the hydrodynamic flow in a Bose-Einstein condensate stirred by a macroscopic object, a blue-detuned laser beam, using nondestructive in situ phase contrast imaging. A critical velocity for the onset of a pressure gradient has been observed, and shown to be density dependent. The technique has been compared to a calorimetric method used previously to measure the heating

R. Onofrio; C. Raman; J. M. Vogels; J. R. Abo-Shaeer; A. P. Chikkatur; W. Ketterle

2000-01-01

337

Experimental observation of the Bogoliubov transformation for a Bose-Eeinstein condensed gas.  

PubMed

Phonons with wave vector q/(planck constant) were optically imprinted into a Bose-Einstein condensate. Their momentum distribution was analyzed using Bragg spectroscopy with a high momentum transfer. The wave function of the phonons was shown to be a superposition of +q and -q free particle momentum states, in agreement with the Bogoliubov quasiparticle picture. PMID:11863793

Vogels, J M; Xu, K; Raman, C; Abo-Shaeer, J R; Ketterle, W

2002-01-28

338

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

339

Deposition of size-selected metal clusters generated by magnetron sputtering and gas condensation: a progress review.  

PubMed

This paper presents a topical review of the production and deposition of size-selected metal clusters generated by magnetron sputtering and gas condensation. Clusters with up to 75,000 atoms can be obtained by controlling the gas pressure in the sputtering source, prior to size selection with a novel (time-of-flight) mass filter. The clusters are deposited on the model graphite substrate to study the cluster-surface interaction. Two regimes for cluster deposition have been identified at elevated impact energies: (i) 'pinning' (ca. 10 eV per atom) and (ii) implantation (ca. 100 eV per atom). Of particular importance is the pinning regime, since this allows the fabrication of monodispersed cluster arrays, which are stable against diffusion at room temperature (and above). The deposition of size-selected metal clusters represents a novel method of preparing surface nanostructures, with potential applications including model catalyst studies and the immobilization of biological molecules. PMID:15306279

Xirouchaki, C; Palmer, R E

2004-01-15

340

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

SciTech Connect

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

Reed, M.H. (Univ. of Oregon, Eugene, OR (United States). Dept. of Geological Sciences)

1993-04-01

341

Off-diagonal long-range order, cycle probabilities, and condensate fraction in the ideal Bose gas.  

PubMed

We discuss the relationship between the cycle probabilities in the path-integral representation of the ideal Bose gas, off-diagonal long-range order, and Bose-Einstein condensation. Starting from the Landsberg recursion relation for the canonic partition function, we use elementary considerations to show that in a box of size L3 the sum of the cycle probabilities of length k>L2 equals the off-diagonal long-range order parameter in the thermodynamic limit. For arbitrary systems of ideal bosons, the integer derivative of the cycle probabilities is related to the probability of condensing k bosons. We use this relation to derive the precise form of the pik in the thermodynamic limit. We also determine the function pik for arbitrary systems. Furthermore, we use the cycle probabilities to compute the probability distribution of the maximum-length cycles both at T=0, where the ideal Bose gas reduces to the study of random permutations, and at finite temperature. We close with comments on the cycle probabilities in interacting Bose gases. PMID:18233625

Chevallier, Maguelonne; Krauth, Werner

2007-11-09

342

Gas transport and separation with ceramic membranes. Part I: Multilayer diffusion and capillary condensation  

Microsoft Academic Search

Multilayer diffusion and capillary condensation of propylene on supported ?-alumina films greatly improved the permeability and selectivity. Multilayer diffusion, occurring at relative pressures of 0.4 to 0.8 strongly increased the permeability of 6 times the Knudsen permeability, yielding permeabilities of 3.2 × 10?5 mol\\/m2-sec-Pa. The occurrence of a maximum in the permeability coincides with blocking of the pore by adsorbate

R. J. R. Uhlhorn; K. Keizer; A. J. Burggraaf

1992-01-01

343

Far-infrared spectra of methane in condensed rare gas matrices under high pressures  

Microsoft Academic Search

Far-infrared absorption spectra of methane molecule diluted in condensed argon, krypton, and xenon matrices have been obtained at 4.2 K under high pressures. It was found that in the CH4-Ar system the vibrational absorption band grew and its peak position showed a blue shift as the applied pressure increased. On the other hand, the rotational absorption bands in the CH4-Xe

T. Nanba; J. Obriot; F. Fondere; Ph. Marteau

1986-01-01

344

METAL SPRAYER FOR USE IN VACUUM OR INERT ATMOSPHERE  

DOEpatents

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

Monroe, R.E.

1958-10-14

345

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

346

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

347

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

2013-05-21

348

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

349

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

350

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

2011-09-08

351

A systematic analysis of elastic electron scattering from inert gases  

Microsoft Academic Search

As part of our simulation of gas discharges in plasma display panels we have been performing critical analyses of available experimental electron-atom cross sections. These studies include comparison between all available measurements and theoretical calculations for elastic electron scattering from inert gases at energies below 1 keV, and a multivariable fitting to obtain some predictive knowledge of these quantities. In

Mehrdad Adibzadeh; Constantine Theodosiou

2001-01-01

352

Drying of Starch Suspension in Spouted Bed with Inert Particles: Physical and Thermal Analysis of Product  

Microsoft Academic Search

Drying in a spouted bed with inert particles promotes high heat and mass transfer rates due to the gas–solid contact, which in turn is successfully achieved by particles' cyclic movements. Because of its advantages and versatility, spouted bed drying of suspensions on inert particles is a potential alternative to flash and spray drying and has received attention in research and

N. R. Pereira; F. C. Godoi; S. C. S. Rocha

2010-01-01

353

Trap- and population-imbalanced two-component Fermi gas in the Bose-Einstein-condensate limit  

SciTech Connect

We study equal mass population imbalanced two-component atomic Fermi gas with unequal trap frequencies (omega{sub a}rrow upnot =omega{sub a}rrow down) at zero temperature using the local density approximation (LDA). We consider the strongly attracting Bose-Einstein condensation (BEC) limit where polarized (gapless) superfluid is stable. The system exhibits shell structure: unpolarized superfluid->polarized superfluid->normal state. Compared to the trap symmetric case, when the majority component is tightly confined the gapless superfluid shell grows in size leading to reduced threshold polarization to form a polarized (gapless) superfluid core. In contrast, when the minority component is tightly confined, we find that the superfluid phase is dominated by the unpolarized superfluid phase with the gapless phase forming a narrow shell. The shell radii for various phases as a function of polarization at different values of trap asymmetry are presented and the features are explained using the phase diagram.

Silotri, S. A. [Theoretical Physics Division, Physical Research Laboratory, Ahmedabad 380009 (India)

2010-01-15

354

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

SciTech Connect

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

NONE

1997-12-16

355

46 CFR 154.1848 - Inerting.  

Code of Federal Regulations, 2010 CFR

... Shipping 5 2009-10-01 2009-10-01 false Inerting. 154.1848 Section 154.1848 Shipping COAST GUARD...CARRYING BULK LIQUEFIED GASES Operations § 154.1848 Inerting. (a) The master shall ensure that: (1)...

2009-10-01

356

46 CFR 154.1848 - Inerting.  

Code of Federal Regulations, 2011 CFR

... Shipping 5 2011-10-01 2011-10-01 false Inerting. 154.1848 Section 154.1848 Shipping COAST GUARD...CARRYING BULK LIQUEFIED GASES Operations § 154.1848 Inerting. (a) The master shall ensure that: (1)...

2011-10-01

357

46 CFR 154.1848 - Inerting.  

Code of Federal Regulations, 2010 CFR

... Shipping 5 2010-10-01 2010-10-01 false Inerting. 154.1848 Section 154.1848 Shipping COAST GUARD...CARRYING BULK LIQUEFIED GASES Operations § 154.1848 Inerting. (a) The master shall ensure that: (1)...

2010-10-01

358

46 CFR 154.1848 - Inerting.  

Code of Federal Regulations, 2012 CFR

... Shipping 5 2012-10-01 2012-10-01 false Inerting. 154.1848 Section 154.1848 Shipping COAST GUARD...CARRYING BULK LIQUEFIED GASES Operations § 154.1848 Inerting. (a) The master shall ensure that: (1)...

2012-10-01

359

Phase transition to Bose-Einstein condensation for a bosonic gas confined in a combined trap  

SciTech Connect

We present a study of phase transition to macroscopic superfluidity for an ultracold bosonic gas confined in a combined trap formed by a one-dimensional optical lattice and a harmonic potential, focusing on the critical temperature of this system and the interference patterns of the Bose gas released from the combined trap. Based on a semiclassical energy spectrum, we develop an analytic approximation for the critical temperature T{sub c}, and compare the analytic results with that obtained by numerical computations. For finite temperatures below T{sub c}, we calculate the interference patterns for both the normal gas and the superfluid gas. The total interference pattern shows a feature of 'peak on a peak'. As a comparison, we also present the experimentally observed interference patterns of {sup 87}Rb atoms released from a one-dimensional optical lattice system in accord with our theoretical model. Our observations are consistent with the theoretical results.

Lue Baolong; Xiong Hongwei [State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China); Tan Xinzhou; Wang Bing; Cao Lijuan [State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China)

2010-11-15

360

Equation of state of a polarized Fermi gas in the Bose-Einstein-condensate limit  

SciTech Connect

We present a theoretical study of the BEC-BCS crossover in the Bose-Einstein-condensate (BEC) regime in the case of an unequal number of fermions of two species. We take full account of the composite nature of the dimers made of fermions. In the limit of low densities, we calculate the ground-state energy of the system, or equivalently the chemical potentials of each species, as well as the one-particle gap and the energy of an 'impurity' immersed in a Fermi sea. For the chemical potentials we go up to order (density){sup 4/3}. The results found involve the exact atom-dimer a{sub AD} and dimer-dimer a{sub DD} scattering lengths and therefore include the three- and four-body problems in the many-body problem. We briefly comment on the importance of the different mean-field corrections for recent experiments.

Alzetto, F.; Leyronas, X. [Laboratoire de Physique Statistique, Ecole Normale Superieure, UPMC Paris 06, Universite Paris Diderot, CNRS, 24 rue Lhomond, F-75005 Paris (France)

2010-04-15

361

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

NASA Astrophysics Data System (ADS)

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.

1992-07-01

362

Combined use of high efficiency liquid and capillary gas chromatography for the determination of polycyclic aromatic hydrocarbons in automotive exhaust condensates and other hydrocarbon mixtures  

Microsoft Academic Search

High efficiency liquid and capillary gas chromatography are used in combination to examine and determine the polycyclic aromatic hydrocarbons present in automotive exhaust condensates from gasoline engines, finished gasolines, and catalytic reformates. The effect of adsorbed water and column temperature on liquid adsorption columns is discussed. The equilibrium conditions can readily be reached and maintained on Waters Porasil T by

T. Doran; N. G. McTaggart

1974-01-01

363

Prediction of the condensation behavior of natural gas: A comparative study of the Peng-Robinson and the simplified-perturbed-hard-chain theory equations of state  

Microsoft Academic Search

For the prediction of the condensation behavior of natural gas, one has to select an equation of state (EoS) which will be accurate in the temperature and pressure range of interest (10 < P\\/bar < 70 bar and 250 < T\\/K < 310). Another requirement of the selected EoS is that is easily can be adapted to a characterization procedure

Marianna E. Voulgaris; Cor J. Peters; Jakob de Swaan Arons

1998-01-01

364

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

365

Nanostructures of crystalline molybdenum trioxide grown by condensation in a carrier gas.  

PubMed

Molybdenum trioxide nanostructures were grown by direct evaporation of MoO3 from a tungsten boat resistively heated in the presence of hydrogen or helium as carrier gas at pressures from 100 to 600 Pa. Crystalline structures such as, nanoribbons, nanofibers, nanoneedles and nanoparticles were obtained at source temperatures below 900 degrees C. On the other hand, at source temperatures above 1000 degrees C, nanoporous structures were obtained. The latter were found more often when hydrogen was used as carrier gas. PMID:19198335

Diaz-Droguett, D E; Fuenzalida, V M; Solorzano, G

2008-11-01

366

Gas condensation within a bundle of carbon nanotubes - effects of screening  

Microsoft Academic Search

We study the low temperature phase behavior of hydrogen within a bundle of carbon nanotubes. Because the carbon environment weakens the attraction between molecules within the same interstitial channel (IC), the ground state of the one-dimensional (1D) system is an uncondensed gas. When the screened attractive interaction between molecules in adjacent ICs is taken into account, the hydrogen ground state

M. K. Kostov; J. C. Lewis; M. W. Cole

2000-01-01

367

Multisystem corrosion monitoring in a condensing flue gas heat exchanger, Phase 2  

Microsoft Academic Search

This report describes the second stage of an investigation of heat exchanger tube corrosion in a cyclic reheat test facility at the Scholz Steam Plant of the Gulf Power Company. Continuous electrochemical corrosion monitoring equipment was installed in a flue gas slipstream in order to investigate attack on tube welds and high corrosion rates at certain other locations that had

D. M. Farrell; W. M. Cox

1991-01-01

368

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

369

Absorption by dissociative continua and Rydberg states in condensed matter: HCl in rare gas matrices  

Microsoft Academic Search

The absorption spectra of HCl in rare gas matrices have been recorded in the first continuum (A1? ? X1?+) region in Kr and Xe matrices and up to 100 nm in Ar matrices. Concentration and temperature effects have been used to distinguish between absorption from monomers and that from clusters. The first continuum band of the monomer is seen to

K. H. Gödderz; N. Schwentner; M. Chergui

1996-01-01

370

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

371

Comparison of Experimental and Numerical Results of Ultra-Lean H2\\/CO Combustion within Inert Porous Media  

Microsoft Academic Search

Combustion of ultra-lean H2\\/CO mixtures, highly diluted in inert gases (N2, H2O, CO2, etc.), was investigated using a developed inert porous media (IPM) burner. Such gas mixtures constitute exhaust gases, produced within Combined Heat and Power (CHP) systems based on high temperature fuel cells (synthesis gas and\\/or anode off-gas). Typical synthesis gas and anode off-gas mixtures of Solid Oxide Fuel

S. Voss; M. Mendes; J. C. Pereira; D. Trimis

372

Methodology For Establishment Of The Radiation Control System At The Karachaganak Oil Gas-Condensate Field  

Microsoft Academic Search

\\u000a At the present time radiological contamination by natural radionuclides of industrial platforms of oil-fields is well-known,\\u000a but far from being resolved problem for many countries. Problem as a whole has gained an environmental-technological value.\\u000a The solution of the problem given requires an introduction at the oil-and-gas production facilities of the complex measures\\u000a on normalization of radiation - ecological conditions, decrease

S. V. Reznikov; K. K. Kadyrzhanov; A. Zh. Tuleushev; Zh. N. Marabaev; S. N. Lukashenko; V. P. Solodukhin; I. V. Kazachevskiy; T. I. Ageyeva

373

Spectroscopy of Carbon Vapor Condensed in Rare-Gas Matrices at 4° and 20°K. I  

Microsoft Academic Search

The molecules vaporizing from graphite at 2300° to 2600°K have been trapped in neon, argon, and xenon matrices at 4° and 20°K. The near-ultraviolet bands of C3, beginning at 4050 Å in the gas, have been observed in the absorption spectra of these matrices but shifted to 4057 Å in neon, 4102 Å in argon, and 4226 Å in xenon.

W. Weltner; P. N. Walsh; C. L. Angell

1964-01-01

374

Gas condensation within a bundle of carbon nanotubes - effects of screening  

Microsoft Academic Search

We study the low temperature phase behavior of hydrogen within a bundle of\\u000acarbon nanotubes. Because the carbon environment weakens the attraction between\\u000amolecules within the same interstitial channel (IC), the ground state of the\\u000aone-dimensional (1D) system is an uncondensed gas. When the screened attractive\\u000ainteraction between molecules in adjacent ICs is taken into account, the\\u000ahydrogen ground state

M. K. Kostov; J. C. Lewis; M. W. Cole

2000-01-01

375

Kinetics and energy states of nanoclusters in the initial stage of homogeneous condensation at high supersaturation degrees  

SciTech Connect

The condensation of metal vapor in an inert gas is studied by the molecular dynamics method. Two condensation regimes are investigated: with maintenance of partial pressure of the metal vapor and with a fixed number of metal atoms in the system. The main focus is the study of the cluster energy distribution over the degrees of freedom and mechanisms of the establishment of thermal equilibrium. It is shown that the internal temperature of a cluster considerably exceeds the buffer gas temperature and the thermal balance is established for a time considerably exceeding the nucleation time. It is found that, when the metal vapor concentration exceeds 0.1 of the argon concentration, the growth of clusters with the highest possible internal energy occurs, the condensation rate being determined only by the rate of heat removal from clusters.

Vorontsov, A. G., E-mail: sas@physics.susu.ac.ru [South Ural State University (Russian Federation); Gel'chinskii, B. R.; Korenchenko, A. E. [Russian Academy of Sciences, Institute of Metallurgy, Ural Branch (Russian Federation)

2012-11-15

376

Binary CF 3Br- and CHF 3–inert flame suppressants: effect of temperature on the flame inhibition effectiveness of CF 3Br and CHF 3  

Microsoft Academic Search

A numerical investigation with detailed chemistry and transport was conducted on the inhibition effectiveness of binary halogenated suppressant and inert gas mixtures. Computational results demonstrate that while positive synergism persists between CF3Br and inert gases, little or negative synergism exists between CHF3 and inert gases. These synergistic effects are attributed to the sensitivity of flame inhibition effectiveness of the chemical

Yuko Saso; Yoshio Ogawa; Naoshi Saito; Hai Wang

1999-01-01

377

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

378

Cement solidification of simulated off-gas condensates from vitrification of low-level nuclear waste solutions.  

PubMed

Solidification in a cementitious matrix is a viable alternative for low-level nuclear waste management; it is therefore important to understand the behavior and properties of such wasteforms. We have examined the cementitious solidification of simulated off-gas waste streams resulting from the vitrification of low-level nuclear waste. Different possible methods for scrubbing the off-gasses from a vitrifier give rise to three possible types of waste compositions: acidic (from aqueous dissolution of volatile NOx and POx carried over from the vitrifier), basic (from neutralizing the former with sodium hydroxide), and fully carbonated (arising from a direct-combustion vitrifier). Six binder compositions were tested in which ordinary Portland cement was replaced at different proportions by fly ash and/or ground granulated blast furnace slag. A high solution to binder ratio of 1l/1 kg was used to minimize the volume of the wasteform and 10% attapulgite clay was added to all mixes to ensure that the fresh mix did not segregate prior to setting. The 28-day compressive strengths decreased when a high proportion of cement was replaced with fly ash, but were increased significantly when the cement was replaced with slag. The heats of hydration at early age for the various solids compositions decreased when cement was replaced with either fly ash or slag; however, for the fly ash mix the low heat was also associated with a significant decrease in compressive strength. High curing temperature (60 degrees C) or the use of extra-fine slag did not significantly affect the compressive strength. Recommendations for choice of binder formulations and treatment of off-gas condensates are discussed. PMID:11478621

Katz, A; Brough, A R; Kirkpatrick, R J; Struble, L J; Sun, G K; Young, J F

2001-01-01

379

Broad iron emission lines in Seyfert galaxies - re-condensation of gas onto an inner disk below the ADAF?  

NASA Astrophysics Data System (ADS)

Context. The number of strong iron K? line detections in Seyfert AGN is clearly growing in the Chandra, XMM-Newton and Suzaku era. The iron emission lines are broad, some are relativistically blurred. These relativistic disk lines have also been observed for galactic black hole X-ray binaries. Thermal components found in hard spectra were interpreted as an indication for a weak inner cool accretion disk underneath a hot corona. Aims: Accretion in low-mass X-ray binaries (LMXB) occurs during phases of high and low mass accretion rate, outburst and quiescence, soft and hard spectral state, respectively. After the soft/hard transition for some sources a thermal component is found, which can be interpreted as sustained by re-condensation of gas from an advection-dominated flow (ADAF) onto the disk. In view of the similarity of accretion flows around stellar mass and supermassive black holes we discuss whether the broad iron emission lines in Seyfert 1 AGN (active galactic nuclei) can be understood as arising from a similar accretion flow geometry as in X-ray binaries. Methods: We derive accretion rates for those Seyfert galaxies for which broad iron emission lines were observed, the "best candidates" in the investigations of Miller (2007, ARA&A, 45, 441) and Nandra et al. (2007, MNRAS, 382, 194). For the evaluation of the Eddington-scaled rates we use the observed X-ray luminosity, bolometric corrections and black hole masses from the literature. Results: The accretion rates derived for the Seyfert galaxies in our sample are less than 0.1 of the Eddington rate for more than half of the sources. For 107 to 108M? black holes in Seyfert 1 AGN this limit corresponds to 0.01 to 0.2 M?/yr. This documents that the sources probably are in a hard spectral state and iron emission lines can arise from an inner weak accretion disk surrounded by an ADAF as predicted by the re-condensation model. Some of the remaining sources with higher accretion rates may be in a spectral state that is comparable to the "very high" state of LMXBs. Conclusions: Our investigation shows that in quite a number of Seyfert AGN the broad iron emission lines may indeed originate in a weak inner disk below the ADAF, close to the black hole, indicating the same accretion flow geometry as recently found for LMXBs. For the accretion history one then concludes that the accretion rates were higher in the outer radii at some earlier time.

Meyer-Hofmeister, E.; Meyer, F.

2011-03-01

380

Effects of surface water on the adsorption of inert gases  

Microsoft Academic Search

Molecular water on mildly outgassed open oxide surfaces can, under special circumstances, significantly reduce the monolayer capacity for inert gas molecules. Non-porous thoria and cubic europia are two examples. The special proviso is that the surface be sufficiently uniform to permit the formation of a well structured, ice-like surface with non-polar character. This type of behavior reaches an extreme for

R. B. Gammage; H. F. Holmes

1976-01-01

381

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

382

[On-line method for measurement of the carbon isotope ratio of atmospheric methane and its application to atmosphere of Yakela condensed gas field].  

PubMed

An on-line method for measurement of the 13C/12C ratio of methane by a gas chromatography/high-temperature conversion/ isotope ratio mass spectrometry (GC/C/MS) technique was developed. This method is less laborious, more rapid (45 min), of high precision (+/- 0.4 x 10(-3)) and by using a small amount of sample (about 200 mL of atmosphere). Its application to isotopic characterization, and hence methane source identification, was demonstrated by examination of atmosphere sample collected in Yakela condensed gas field, China. The average 13C/12C ratio of atmospheric methane in Yakela field was -45.0 x 10(-3) heavier by 1.2 x 10(-3) -2.0 x 10(-3) than the global average. This is caused by seepage and diffusing of methane from Yakela condensed gas reservoir. The concentrations of atmospheric methane in daytimes are found to be lower than those in nighttimes, and the corresponding 13C/12C ratios in daytimes are lighter compared to those in nighttimes, a phenomena probably caused by the fact that a small part of methane from Yakela condensate reservoir is consumed in soil's surface under sunlight. PMID:16599113

Tang, Jun-Hong; Bao, Zheng-Yu; Xiang, Wu; Qiao, Sheng-Ying; Li, Bing

2006-01-01

383

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; Going, J.; Chatrathi, K. [Fike Corp., Blue Springs, MO (United States)

1999-05-01

384

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

385

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.

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

386

Kinetic multi-layer model of gas-particle interactions in aerosols and clouds (KM-GAP): linking condensation, evaporation and chemical reactions of organics, oxidants and water  

NASA Astrophysics Data System (ADS)

We present a novel kinetic multi-layer model for gas-particle interactions in aerosols and clouds (KM-GAP) that treats explicitly all steps of mass transport and chemical reaction of semi-volatile species partitioning between gas phase, particle surface and particle bulk. KM-GAP is based on the PRA model framework (Pöschl-Rudich-Ammann, 2007), and it includes gas phase diffusion, reversible adsorption, surface reactions, bulk diffusion and reaction, as well as condensation, evaporation and heat transfer. The size change of atmospheric particles and the temporal evolution and spatial profile of the concentration of individual chemical species can be modeled along with gas uptake and accommodation coefficients. Depending on the complexity of the investigated system and the computational constraints, unlimited numbers of semi-volatile species, chemical reactions, and physical processes can be treated, and the model shall help to bridge gaps in the understanding and quantification of multiphase chemistry and microphysics in atmospheric aerosols and clouds. In this study we demonstrate how KM-GAP can be used to analyze, interpret and design experimental investigations of changes in particle size and chemical composition in response to condensation, evaporation, and chemical reaction. For the condensational growth of water droplets, our kinetic model results provide a direct link between laboratory observations and molecular dynamic simulations, confirming that the accommodation coefficient of water at ~270 K is close to unity (Winkler et al., 2006). Literature data on the evaporation of dioctyl phthalate as a function of particle size and time can be reproduced, and the model results suggest that changes in the experimental conditions like aerosol particle concentration and chamber geometry may influence the evaporation kinetics and can be optimized for efficient probing of specific physical effects and parameters. With regard to oxidative aging of organic aerosol particles, we illustrate how the formation and evaporation of volatile reaction products like nonanal can cause a decrease in the size of oleic acid particles exposed to ozone.

Shiraiwa, M.; Pfrang, C.; Koop, T.; Pöschl, U.

2012-03-01

387

Kinetic multi-layer model of gas-particle interactions in aerosols and clouds (KM-GAP): linking condensation, evaporation and chemical reactions of organics, oxidants and water  

NASA Astrophysics Data System (ADS)

We present a novel kinetic multi-layer model for gas-particle interactions in aerosols and clouds (KM-GAP) that treats explicitly all steps of mass transport and chemical reaction of semi-volatile species partitioning between gas phase, particle surface and particle bulk. KM-GAP is based on the PRA model framework (Pöschl-Rudich-Ammann, 2007), and it includes gas phase diffusion, reversible adsorption, surface reactions, bulk diffusion and reaction, as well as condensation, evaporation and heat transfer. The size change of atmospheric particles and the temporal evolution and spatial profile of the concentration of individual chemical species can be modeled along with gas uptake and accommodation coefficients. Depending on the complexity of the investigated system, unlimited numbers of semi-volatile species, chemical reactions, and physical processes can be treated, and the model shall help to bridge gaps in the understanding and quantification of multiphase chemistry and microphysics in atmospheric aerosols and clouds. In this study we demonstrate how KM-GAP can be used to analyze, interpret and design experimental investigations of changes in particle size and chemical composition in response to condensation, evaporation, and chemical reaction. For the condensational growth of water droplets, our kinetic model results provide a direct link between laboratory observations and molecular dynamic simulations, confirming that the accommodation coefficient of water at ~270 K is close to unity. Literature data on the evaporation of dioctyl phthalate as a function of particle size and time can be reproduced, and the model results suggest that changes in the experimental conditions like aerosol particle concentration and chamber geometry may influence the evaporation kinetics and can be optimized for efficient probing of specific physical effects and parameters. With regard to oxidative aging of organic aerosol particles, we illustrate how the formation and evaporation of volatile reaction products like nonanal can cause a decrease in the size of oleic acid particles exposed to ozone.

Shiraiwa, M.; Pfrang, C.; Koop, T.; Pöschl, U.

2011-12-01

388

Liquid Fuel Combustion Using Porous Inert Media.  

National Technical Information Service (NTIS)

Combustion using porous inert media (PIM) offers benefits such as high power density, stable operation over a wider turndown ratio, homogeneous product gases, lower combustion noise and reduced emissions of NOx, CO, particulates, etc. Much of the previous...

A. K. Agrawal S. R. Gollahalli

2006-01-01

389

INERT Atmosphere confinement operability test procedure  

SciTech Connect

This Operability Test Procedure (OTP) provides instructions for testing operability of the Inert Atmosphere Confinement (IAC). The Inert Atmosphere Confinement was designed and built for opening cans of metal items that might have hydrided surfaces. Unreviewed Safety Question (USQ) PFP-97-005 addresses the discovery of suspected plutonium hydride forming on plutonium metal currently stored in the Plutonium Finishing Plant vaults. Plutonium hydride reacts quickly with air, liberating energy. The Inert Atmosphere Confinement was designed to prevent this sudden liberation of energy by opening the material in an inert argon atmosphere instead of the normal glovebox atmosphere. The IAC is located in glovebox HC-21A, room 230B of the 234-5Z Building at the Plutonium Finishing Plant (PFP) in the 200-West Area of the Hanford Site.

RISENMAY, H.R.

1999-02-22

390

Axial grading of inert matrix fuels  

SciTech Connect

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

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

2012-07-01

391

[The characteristics of the behavior and brain lipid peroxidation function of rats in acute inhalation exposure to a hydrogen sulfide-containing gas condensate].  

PubMed

As a result of the effect of the gas condensate containing hydrogen sulfide a depression takes place of orienting-investigatory activity of Wistar male rats in conditions of open field, disturbance of elaboration and reproduction of conditioned reflex of two-way avoidance, surplus accumulation in the cerebral cortex tissue of products of peroxide lipids oxidation and depression of catalase. The changes were of cyclic character and returned to the level of the control animals in 48 h after the finishing of the effect. PMID:1323184

Boev, V M; Perepelkin, S V; Solovykh, D I

392

Gas-particle interactions of tropospheric aerosols: Kinetic and thermodynamic perspectives of multiphase chemical reactions, amorphous organic substances, and the activation of cloud condensation nuclei  

NASA Astrophysics Data System (ADS)

Aerosols are of central importance in the Earth system, influencing the atmosphere, biosphere, climate, and public health. This article outlines recent advances and perspectives in the investigation and effects of gas-particle interactions in tropospheric aerosols, including physical, chemical and biological aspects. In particular, it addresses how multiphase processes and heterogeneous chemical reactions can be efficiently described by kinetic models, how amorphous organic substances can influence the kinetics of water uptake and phase transitions, and how the abundance and activation of cloud condensation nuclei (CCN) depend on thermodynamic and kinetic parameters.

Pöschl, Ulrich

2011-08-01

393

Electron Clusters in Inert Gases  

Microsoft Academic Search

This Letter addresses the counterintuitive behavior of electrons injected into dense cryogenic media with negative scattering length L. Instead of strongly reduced mobility at all but the lowest densities due to the polaronic effect involving the formation of density enhancement clusters (expected in the theory with a simple gas-electron interaction successfully applied earlier to electrons in helium where L>0) which

S. Nazin; V. Shikin

2008-01-01

394

Models of coefficient of thermal expansion (CTE) for Gilsocarbon graphites irradiated in inert and oxidising environments  

NASA Astrophysics Data System (ADS)

This paper presents the development and validation of an empirical model of radiation effects on coefficient of thermal expansion (CTE) for the Gilsocarbon graphites used in Advanced Gas-cooled Reactors (AGRs). The combined irradiation and oxidation model is based in part on a new model of fast neutron damage in inert environment. The new inert model shows an increase to an "upper shelf" irradiated CTE value at very low dose, then CTE values decrease with increasing dose following a hyperbolic tangent function. The effect of the actual exposure in AGRs is modelled by shifting the inert model in both dose and CTE directions to agree with the CTE measurements on material trepanned from moderator bricks in operating AGRs. The shift in the inert model that is needed to match the trepanned data varies significantly by reactor. The new model predicts randomly-selected validation data that were not used in model fitting as well as it fits the calibration data.

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

2013-05-01

395

High-order numerical simulation and modelling of the interaction of energetic and inert materials  

Microsoft Academic Search

We present an integrated algorithm on a Eulerian grid, for multimaterial simulations of energetic and inert materials modelled by non-ideal equations of state. We employ high-resolution shock capturing numerical algorithms for each material inside its domain and use an overlap domain method across the interface, maintained by a recently developed, hybrid, level-set algorithm. For applications to condensed explosives we implement

D. Scott Stewart; Sunhee Yoo; B. L. Wescott

2007-01-01

396

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

Microsoft Academic Search

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

Philip Johnson

1998-01-01

397

CONDENSATION CAN  

DOEpatents

An apparatus is designed for condensing a vapor to a solid at relatively low back pressures. The apparatus comprises a closed condensing chamber, a vapor inlet tube extending to the central region of the chamber, a co-axial tubular shield surrounding the inlet tube, means for heating the inlet tube at a point outside the condensing chamber, and means for refrigeratirg the said chamber. (AEC)

Booth, E.T. Jr.; Pontius, R.B.; Jacobsohn, B.A.; Slade, C.B.

1962-03-01

398

Phase transformations in condensate pool development  

NASA Astrophysics Data System (ADS)

The phase behavior of a gas-condensate mixture in the pool depletion process and the influence of porosity on the amount of extracted concentrate and gas and on the gas phase composition have been studied experimentally. A possible approach to the differential condensation process has been determined. The substantial influence of the zone of condensate micronuclei formation in a porous medium on the parameters of phase condensation and on the technological parameters of condensate pool development have been established for the first time.

Abasov, M. T.; Abbasov, Z. Ya.; Fataliev, V. M.; Hamidov, N. N.; Mammadova, G. G.

2009-08-01

399

Studies on Pressure Response of Gas Bubbles Contributions of Condensed Droplets in Bubbles Generated by a Uniform Nucleation.  

National Technical Information Service (NTIS)

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...

Y. Matsumoto

1988-01-01

400

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

Microsoft Academic Search

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

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

2012-01-01

401

Condensation of steam and R113 on a bank of horizontal tubes in the presence of a noncondensing gas  

Microsoft Academic Search

Data are presented for condensation from steam-air and R113-air mixtures on a bank of horizontal tubes. The test bank consisted of 10 staggered rows of four and five tubes per row. Good agreement with single-tube theory was found for the top rows when account was taken of the variation in bulk air concentration, vapor velocity, and temperature down the bank.

R. Abdullah; J. R. Cooper; A. Briggs; J. W. Rose

1995-01-01

402

Visualization of the freeze\\/thaw characteristics of a copper\\/water heat pipe - Effects of non-condensible gas  

Microsoft Academic Search

The freeze\\/thaw characteristics of a copper\\/water heat pipe of rectangular cross section were investigated experimentally to determine the effect of variations in the amount of non-condensible gases (NCG) present. The transient internal temperature profiles in both the liquid and vapor channels are presented along with contours of the frozen fluid configuration obtained through visual observation. Several interesting phenomena were observed

J. M. Ochterbeck; G. P. Peterson

1991-01-01

403

Gibbons-Hawking effect in the sonic de Sitter space-time of an expanding Bose-Einstein-condensed gas.  

PubMed

We propose an experimental scheme to observe the Gibbons-Hawking effect in the acoustic analog of a (1+1)-dimensional de Sitter universe, produced in an expanding, cigar-shaped Bose-Einstein condensate. It is shown that a two-level system created at the center of the trap, an atomic quantum dot interacting with phonons, observes a thermal Bose distribution at the de Sitter temperature. PMID:14683099

Fedichev, Petr O; Fischer, Uwe R

2003-12-11

404

Inert strength of pristine silica glass fibers  

SciTech Connect

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

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

1993-11-01

405

The Condensation Coefficient of Aln.  

National Technical Information Service (NTIS)

The condensation coefficient of AlN was measured by following the rate of exchange is isotopic N2 gas (N15) with AlN14(s) and that of N2 gas (N14) with AlN15(s) using a time-of-flight mass spectrometer. The isotopic N2 gas (N15) was generated by decomposi...

M. Hoch D. Ramakrishnan

1965-01-01

406

Investigation of a Hall MHD channel with an ionization-unstable plasma of inert gases  

Microsoft Academic Search

We investigate a promising scheme for using ionization-unstable plasmas of pure inert gases as the working medium for a magnetohydrodynamic\\u000a (MHD) closed-cycle generator. Our experiments were carried out using a disc Hall MHD channel, with the flux of ionized gas\\u000a created in a shock tube. Our working gas was xenon. In these experiments we measured the gas pressure, the flow

R. V. Vasil’eva; E. A. D’yakonova; A. V. Erofeev; A. D. Zuev; T. A. Lapushkina; A. A. Markhotok

1997-01-01

407

Macroscopic quantum tunneling of a bose condensate  

Microsoft Academic Search

We study, by means of a variational method, the stability of a condensate in a magnetically trapped atomic Bose gas with a negative scattering length and find that the condensate is unstable in general. However, for temperatures sufficiently close to the critical temperature the condensate turns out to be metastable. For that case we determine in the usual WKB approximation

H. T. C. Stoof

1997-01-01

408

Macroscopic superpositions of Bose-Einstein condensates  

Microsoft Academic Search

We consider two dilute gas Bose-Einstein condensates with opposite velocities from which a monochromatic light field detuned far from the resonance of the optical transition is coherently scattered. In the thermodynamic limit, when the relative fluctuations of the atom number difference between the two condensates vanish, the relative phase between the Bose-Einstein condensates may be established in a superposition state

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

1998-01-01

409

Inerting Aircraft Fuel Systems Using Exhaust Gases.  

National Technical Information Service (NTIS)

Our purpose in this proposal was to determine the feasibility of using carbon dioxide, possibly obtained from aircraft exhaust gases as a substance to inert the fuel contained in fuel tanks aboard aircraft. To do this, we decided to look at the effects ca...

D. G. Hehemann

2002-01-01

410

Synthesis of mechanical networks: the inerter  

Microsoft Academic Search

The paper is concerned with the problem of synthesis of (passive) mechanical one-port networks. One of the main contributions of the paper is the introduction of a device, which win be called the inerter, which is the true network dual of the spring. This contrasts with the mass element which, by definition, always has one terminal connected to ground. The

Malcolm C. Smith

2002-01-01

411

Diamondoid Characterization in Condensate by Comprehensive Two-Dimensional Gas Chromatography with Time-of-Flight Mass Spectrometry: The Junggar Basin of Northwest China.  

PubMed

Diamondoids in crude oil are useful for assessing the maturity of oil in high maturation. However, they are very difficult to separate and accurately quantify by conventional geochemical methods due to their low abundance in oil. In this paper, we use comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC×GC-TOFMS) to study the compounds in condensates from the Junggar Basin of northwest China and address their geological and geochemical applications. GC×GC-TOFMS improves the resolution and separation efficiency of the compounds. It not only separates the compounds that coelute in conventional GC-MS (e.g., 4, 8-dimethyl-diamantane and trimethyl-diamantane) but also allows the identification of compounds that were not previously detected (e.g., trimethyl-diamantane (15A)). A reversed-phase column system improves the separation capabilities over the normal phase column system. The diamondoid indexes indicate that a representative condensate from Well DX 10 is highly mature with equivalent Ro being approximately 1.5%. PMID:23109861

Li, Shuifu; Hu, Shouzhi; Cao, Jian; Wu, Ming; Zhang, Dongmei

2012-09-12

412

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

Microsoft Academic Search

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

Roberta C. Hamme; Steven R. Emerson

2002-01-01

413

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

Microsoft Academic Search

Zirconium carbide is being actively considered for use as an inert matrix material in composite nuclear fuel for gas-cooled fast reactors. ZrC can be produced either by the endothermic carbothermal reduction of zirconium dioxide or by the direct exothermic reaction of pure zirconium and graphite powder mixtures. The exothermic reaction is classified as combustion synthesis or self heating synthesis. Experiments

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

2008-01-01

414

Experimental study of effect of inert gases on extinction of laminar diffusion flames  

Microsoft Academic Search

The limiting fuel concentration and the limiting oxygen concentration required to maintain the diffusion flame and the limit flame temperatures were measured using a counterflow diffusion flame established in the forward stagnation region of a porous cylinder. The fuels used were methane and hydrogen, and three kinds of inert gas (nitrogen, argon, and helium) were used as the diluent. The

S. Ishizuka; H. Tsuji

1981-01-01

415

Infrared applications for steam turbine condenser systems  

Microsoft Academic Search

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

Mark A. Lanius

2000-01-01

416

Condensation Processes in Geothermal Systems  

NASA Astrophysics Data System (ADS)

We model condensation processes in geothermal systems to understand how this process changes fluid chemistry. We assume two processes operate in geothermal systems: 1) condensation of a vapor phase derived by boiling an aqueous geothermal fluid into a cool near surface water and 2) condensation of a magmatic vapor by a deep circulating meteoric thermal fluid. It is assumed that the condensation process has two stages. Initially the condensing fluid is under saturated in gaseous species. Condensation of the vapor phase continues until the pressure on the fluid equals the sum of the partial pressures of water and the dissolved gaseous species. At that time bubbles flux through the condensing fluid. In time the fluid and fluxing gas phase come to equilibrium. Calculation shows that during the second stage of the condensation process the liquid phase becomes enriched in more soluble gaseous species like CO2 and H2S, and depleted in less soluble species like CH4 and N2. Stage 2 condensation processes can therefore be monitored by ratios of more and less condensable species like CO2/N2. Condensation of vapor released by boiling geothermal fluids results in liquids with high concentrations of H2S and CO2 like is seen in geothermal system steam-heated waters. Condensation of a magmatic vapor into circulating meteoric water has been proposed, but not well demonstrated. We compare to our models the Cerro Prieto, Mexico gas analysis data set collected over twelve years time by USGS personnel. It was assumed for modeling that the Cerro Prieto geothermal fluids are circulating meteoritic fluids with N2/Ar ratios about 40 to which is added a magmatic vapor with N2/Ar ratio = 400. The Cerro Prieto analyses show a strong correlation between N2/Ar and CO2/N2 as predicted by calculation. Two dimensional image plots of well N2/Ar + CO2/N2 show a bull's-eye pattern on the geothermal field. Image plots of analyses collected over a year or less time show N2/Ar and CO2/N2 hot spots. Plotting data for individual wells show a hysteresis like loops on time vs. CO2/N2 diagrams. Our analysis demonstrates that condensation of magmatic vapor into convecting meteoric waters is a viable process. Condensation explains variations in Cerro Prieto geothermal system gas chemistry and is compatible with helium isotope data. Locally condensation appears to wax and wane over a time periods of about 10 years.

Norman, D. I.; Moore, J. N.

2005-12-01

417

46 CFR 154.1740 - Vinyl chloride: Inhibiting and inerting.  

Code of Federal Regulations, 2011 CFR

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

2011-10-01

418

46 CFR 154.1740 - Vinyl chloride: Inhibiting and inerting.  

Code of Federal Regulations, 2010 CFR

... 2010-10-01 false Vinyl chloride: Inhibiting and inerting. 154.1740 Section 154.1740 Shipping COAST GUARD...Requirements § 154.1740 Vinyl chloride: Inhibiting and inerting. When a vessel is carrying vinyl chloride, the master...

2010-10-01

419

46 CFR 154.1740 - Vinyl chloride: Inhibiting and inerting.  

Code of Federal Regulations, 2012 CFR

... 2012-10-01 false Vinyl chloride: Inhibiting and inerting. 154.1740 Section 154.1740 Shipping COAST GUARD...Requirements § 154.1740 Vinyl chloride: Inhibiting and inerting. When a vessel is carrying vinyl chloride, the master...

2012-10-01

420

46 CFR 154.1740 - Vinyl chloride: Inhibiting and inerting.  

Code of Federal Regulations, 2010 CFR

... 2009-10-01 false Vinyl chloride: Inhibiting and inerting. 154.1740 Section 154.1740 Shipping COAST GUARD...Requirements § 154.1740 Vinyl chloride: Inhibiting and inerting. When a vessel is carrying vinyl chloride, the master...

2009-10-01

421

Influence of inertance on respiratory mechanics measurements in mechanically ventilated puppies.  

PubMed

The complete equation of motion for a single compartment model (SCM) includes an inertance term to describe pressure changes in phase with acceleration, as well as terms for resistance and elastance. Inertance has traditionally been excluded from the model when measuring respiratory mechanics at conventional ventilatory frequencies in mature respiratory systems. However, this omission has been questioned recently for measurements of respiratory mechanics in intubated infants where higher ventilation frequencies and smaller tracheal tubes are the norm. We investigated 1) the significance of inertance in an immature respiratory system during mechanical ventilation, and 2) the effect of omitting it from the model on estimates of respiratory mechanics. Six anesthetised, paralysed and mechanically ventilated puppies (2.6-3.9 kg) were studied. A SCM, including an inertance term was fitted to measurements of flow and airway opening (P(AO)) or transpulmonary (P(TP)) pressure using multiple linear regression to estimate respiratory system and lung resistance (R(RS), R(L)), elastance (E(RS), E(L)) and inertance (I(RS), I(L)) respectively, at various ventilation frequencies (0.2-2 Hz). Data obtained at each ventilation frequency were also fitted with a similar model without the inertance term. Inertance contributed significantly to the model at frequencies greater than approximately 0.3-0.5 Hz (20-30 breaths per minute), with I(RS) dominated by the lung. The importance of including the inertance term in the model increased as ventilation frequency increased. Exclusion of inertance from the model led to underestimation of E(RS) and E(L), but no errors in estimates of R(RS) or R(L). The errors increased with ventilation frequency to approximately 10-20% for E(RS) and approximately 10-40% for E(L) at 2 Hz. While inertance contributed significantly to the SCM at ventilation frequencies typically required to maintain normal gas exchange in puppies, the errors from excluding this term were small: <3% for E(RS) and <9% for E(L). PMID:10423313

Lanteri, C J; Petak, F; Gurrin, L; Sly, P D

1999-08-01

422

Phase characterization and grain size effects of nanophase Y2O3, ZrO2 and Y2O3-ZrO2 composites produced by the gas-phase condensation technique.  

National Technical Information Service (NTIS)

Nanophase (n-) ZrO(sub 2) was produced in its pure and partially stabilized form by the gas-phase condensation method. The material was examined by x-ray diffraction and Raman scattering to obtain information on the structural evolution of the material du...

C. M. Foster G. R. Bai J. C. Parker M. N. Ali

1992-01-01

423

Thermal regeneration of granular activated carbons using inert atmospheric conditions.  

PubMed

Thermal regeneration is increasingly being used for the recovery of field-spent granular activated carbons (GAC) generated by the water treatment industry. Despite its commercial success, conventional methods using oxidising conditions (usually steam) are known to damage the porosity of the regenerated carbons, thus reducing their adsorption capacity and economic value. This paper presents a comparative investigation into the benefits of using inert conditions for the regeneration of field-spent GAC. For the purpose of this work, a sample of spent carbon was regenerated in nitrogen and in steam to different degrees of burn off. The resulting samples were analysed for their porosity and surface area characteristics using nitrogen gas adsorption, and for their aqueous adsorption capacities using phenol and methylene blue. Experimental results showed that steam was sightly more effective than nitrogen at regenerating the total micropore volume and BET surface area of the carbons. However, these benefits were largely counteracted by greater losses in the carbon yield and damage to the narrow microporosity. Carbons regenerated in nitrogen exhibited greater adsorption capacities for the adsorption of small molecular size compounds (phenol) from solution, while carbons regenerated in steam adsorbed larger molecular size compounds (methylene blue) more effectively. However, when product yields were taken into consideration, inert regeneration was found to produce significantly better results than steam regeneration. An optimum process temperature was determined to be 950 degrees C. PMID:12523505

San Miguel, G; Lambert, S D; Graham, N J D

2002-12-01

424

Prediction of the condensation behavior of natural gas: A comparative study of the Peng-Robinson and the simplified-perturbed-hard-chain theory equations of state  

SciTech Connect

For the prediction of the condensation behavior of natural gas, one has to select an equation of state (EoS) which will be accurate in the temperature and pressure range of interest (10 < P/bar < 70 bar and 250 < T/K < 310). Another requirement of the selected EoS is that is easily can be adapted to a characterization procedure for the heavy-end fraction. For that purpose, two equations were tested: the Peng-Robinson (PR), which is one of the most applied cubic EoS, and the simplified-perturbed-hard-chain theory (SPHCT) equation, which is one of the simplest EoS based on sound statistical mechanical principles. In the underlying study, their predictive capabilities for the prediction of saturated vapor pressures of pure compounds and vapor/liquid equilibrium pressures for binary mixtures are compared. Only components present in natural gas are considered. In addition, new pure-component parameters for the SPHCT EoS for n-alkanes are evaluated. Also a method to find the characteristic energy for non-n-alkane molecules is proposed in this study. This study revealed that the PR EoS predicts more accurately the liquid phase composition, whereas the SPHCT EoS is superior for the gas phase prediction, especially for asymmetric binary mixtures. It was concluded that, with respect to the purpose of this study, both EoS, when used with optimum binary interaction parameters, have an equivalent descriptive accuracy. Therefore, the simpler PR EoS was preferred to describe natural gas mixtures.

Voulgaris, M.E.; Peters, C.J.; Swaan Arons, J. de [Delft Univ. of Technology (Netherlands). Lab. of Applied Thermodynamics and Phase Equilibria

1998-05-01

425

Trilepton signals in the inert doublet model  

SciTech Connect

In this work, we investigate the prospects for detecting the Inert Doublet Model via the trilepton channel at the LHC. We present a set of representative benchmark scenarios in which all applicable constraints are satisfied, and show that in some of these scenarios, it is possible to obtain a signal at the 5{sigma} significance level or better with integrated luminosity of 300 fb{sup -1}.

Miao, Xinyu; Su, Shufang [Department of Physics, University of Arizona, Tucson, Arizona 85721 (United States); Thomas, Brooks [Department of Physics, University of Arizona, Tucson, Arizona 85721 (United States); Department of Physics, University of Maryland, College Park, Maryland 20742 (United States)

2010-08-01

426

Deoxygenation of dodecanoic acid under inert atmosphere  

Microsoft Academic Search

A laboratory-scale fixed bed reactor (down-flow) was developed for the deoxygenation of dodecanoic (lauric) acid under inert atmosphere. This reaction can be utilized to produce renewable diesel components. The main products were undecane (decarboxylation) and undecene (decarbonylation). The catalysts were a palladium catalyst supported on mesoporous carbon, Sibunit (egg-shell type with spherical granules of 1.6–2.0mm in diameter), and a commercial

Heidi Bernas; Kari Eränen; Irina Simakova; Anne-Riikka Leino; Krisztián Kordás; Jukka Myllyoja; Päivi Mäki-Arvela; Tapio Salmi; Dmitry Yu. Murzin

2010-01-01

427

Bose-Einstein condensation of sodium atoms  

Microsoft Academic Search

Summary form only given. Bose-Einstein condensation (BEG) has been observed in a dilute gas of sodium atoms. A Bose-Einstein condensate consists of a macroscopic population of the ground state of the system and is a coherent state of matter. In an ideal gas, this phase transition is purely quantum statistical. The study of BEC in weakly interacting systems that can

N. I. Van Druten; D. S. Durfee; K. B. Davis; M.-O. Mewes; M. R. Andrews; D. M. Kurn; W. Ketterle

1996-01-01

428

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

PubMed

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

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

2012-05-14

429

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

430

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

SciTech Connect

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

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

1991-02-01

431

Studies of magnetically and optically confined Bose-Einstein condensates  

Microsoft Academic Search

The study of Bose-Einstein condensation in DC magnetic traps has yielded a rich harvest of researches. By studying the process of condensate formation in a super-cooled atomic gas, one not only verifies theories describing dynamic properties of the condensate, but also discerns the stimulated character of collisions into the condensate from the surrounding vapor. Studies of sound propagation have explored

D. M. Stanper-Kurn; M. R. Andrews; A. P. Chikkatur; S. Inouye; H.-J. Miesner; J. Stenger; W. Ketterle

1998-01-01

432

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.

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

2008-01-01

433

Polyvinyl alcohol battery separator containing inert filler  

SciTech Connect

A cross-linked polyvinyl alcohol battery separator is disclosed. A particulate filler, inert to alkaline electrolyte of an alkaline battery, is incorporated in the separator in an amount of 1-20% by weight, based on the weight of the polyvinyl alcohol, and is dispersed throughout the product. Incorporation of the filler enhences performance and increases cycle life of alkaline batteries when compared with batteries containing a similar separator not containing filler. Suitable fillers include titanates, silicates, zirconates, aluminates, wood floor, lignin, and titania. Particle size is not greater than about 50 microns.

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

1981-06-01

434

Fire-Extinguishing Effectiveness of 1-Bromo-3,3,3-Trifluoropropene\\/Inert Gaseous Mixture Evaluated by Cup Burner Method  

Microsoft Academic Search

1-bromo-3,3,3-trifluoropropene with low extinguishing concentration has been identified, but it has high boiling points and is not suitable replacements for halon 1301. However, mixtures of 1-bromo-3,3,3-trifluoropropene in an inert gas could produce fire-extinguishing agents with many of the desirable properties of halon 1301. To study binary fire suppressants, one has to determine the extinguishing concentration of the 1-bromo-3,3,3-trifluoropropene\\/inert gas mixtures.

Zhang Yongfeng; Lin Lin; Jin Xiang; Huang Xin; Liao Guangxuan

2007-01-01

435

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

2013-03-14

436

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

437

State of an adiabatic expanding and condensing vapor or slow, medium, and fast explosions into a vacuum  

SciTech Connect

A hot dense vapor expanding adiabatically into a vacuum is studied, A condensed phase develops after saturation and supercooling conditions have been achieved. The final state of the system consists of liquid drops in a expanding, cooling vapor. The final condensed mole fraction depends on the drop growth rate compared to the fractional volume rate of expansion at the time saturation is achieved. Drops are produced by a nonequilibrium collision process during supercooling of the vapor. The dependence of the number of drops on various factors is established. The First Law of Thermodynamics is used to solve for the evolution of the system, assuming the volume expansion rate is known. The initial vapor can include an inert gas that does not condense in the temperature range of interest. The vapors are treated as ideal gases until saturation occurs. Slow expansions result in the highest condensed mole fractions. Slow expansions are the result of one-dimensional versus three-dimensional expansions and from saturation occurring at high temperatures and densities. The size per drop depends mostly on how many drops are formed in the nonequilibrium supercooling process. 9 refs., 23 figs., 2 tabs.

Strobel, G.L. (Los Alamos National Lab., NM (USA) Georgia Univ., Athens, GA (USA). Dept. of Physics)

1990-04-01

438

Photochemical activity of Titan’s low-altitude condensed haze  

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

439

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

440

Experimental investigation of the length of a free diffusion jet of fuel gases diluted with inert gases  

NASA Astrophysics Data System (ADS)

Experimental investigation of the length of single burning jets of methane and hydrogen previously diluted with an inert gas (nitrogen or helium) was carried out. Efflux of fuel gases into the atmosphere occurred through cylindrical extension pieces 4 and 8 mm in diameter. The Reynolds numbers at the cut of a piece varied in the range from 400 to 12,000. A clearly defined dependence of the jet length on the quality of the added inert gas is obtained. The correlation of experimental data made it possible to recommend formulas for engineering calculations of free laminar and turbulent jets.

Polezhaev, Yu. V.; Vorob'ev, B. A.; Korovin, G. K.; Lamden, D. I.; Mostinskii, I. L.; Shigin, R. L.

2010-05-01

441

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

2013-08-19

442

Coal pulverizer inerting and fire extinguishing system  

SciTech Connect

A bowl mill is described having a substantially closed separator body, a rotatable grinding surface mounted for rotation in a first direction within the separator body and upon which pulverization of material is effected, material supply means supported within the separator body for supplying material to be pulverized to the grinding surface and having a first portion projecting outwardly of the separator body, outlet means supported on the separator body for discharging from the bowl mill material that has been pulverized therewithin, and air inlet means for supplying air to the interior of the separator body for transporting material that has been pulverized on the grinding surface therefrom to the outlet means for discharging from the bowl mill. The improvement consists of a combination inerting and fire extinguishing system.

Kmiotek, S.E.; Johnson, M.P.; Rogers, J.D.

1988-07-05

443

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

444

Cosmological tachyon condensation  

SciTech Connect

We consider the prospects for dark matter/energy unification in k-essence type cosmologies. 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.

Bilic, Neven; Tupper, Gary B.; Viollier, Raoul D. [Rudjer Boskovic Institute, 10002 Zagreb (Croatia); Centre of Theoretical Physics and Astrophysics, University of Cape Town, Rondebosch 7701 (South Africa)

2009-07-15

445

Upgrading of condensibles from coal devolatilization  

Microsoft Academic Search

This project has only been underway a very short time and initial efforts have been concerned with upgrading studies on the condensibles from the United Coal Company's mild gasification process. Ultimate analysis of the raw condensible product had been performed together with more detailed characterizations employing gas chromatography (GC) using flame ionization and nitrogen-specific detectors. In addition, gel permeation (GPC)

J. E. Mrochek; C. D. Scott

1987-01-01

446

Understanding Condensation  

NSDL National Science Digital Library

Monica Hartman, Assistant Director for Science in St. Clair County, Michigan, conducted this research while she was the learning specialist in a small suburban district just outside a large Midwestern city. While teaching full time in this district she was also completing her doctoral program in education at the University of Michigan. In this chapter, she tells the story of a "science talk" about condensation among fifth graders. She acted as a source and facilitator of change as she and the fifth-grade teacher worked collaboratively to help students share responsibility for their own learning. She describes their continual assessment of student understanding that occurred as their students struggled to explain observations and as they, the teachers, carefully resisted the temptation to end the struggle by saying "that's right!"

Hartman, Monica

2007-12-01

447

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

448

Electrochemical codeposition of inert particles in a metallic matrix  

Microsoft Academic Search

A survey on electrochemical codeposition of inert particles in a metallic matrix is given. Particles held in suspension in an electroplating bath are codeposited with the metal during electrodeposition. The particles used are inert to the bath and can be of different types, that is, pure metals, ceramics or organic materials. Combining this variety of types of particles with the

A. Hovestad; L. J. J. Janssen

1995-01-01

449

Performance Benefits in Passive Vehicle Suspensions Employing Inerters  

Microsoft Academic Search

A new ideal mechanical one-port network element named the inerter was recently introduced, and shown to be realisable, with the property that the applied force is proportional to the relative acceleration across the element. This paper makes a comparative study of several simple passive suspension struts, each containing at most one damper and inerter as a preliminary investigation into the

Malcolm C. Smith; Fu-Cheng Wang

2004-01-01

450

Electrolytic production of high purity aluminum using inert anodes  

DOEpatents

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

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

2001-01-01

451

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

452

Inertance Tube Modeling and the Effects of Temperature.  

National Technical Information Service (NTIS)

Pulse tube refrigerators (PTRs) have made dramatic improvements in reliability efficiency and usage. Inertance tube PTRs have been one of the keys to these improvements. The inertance tube is the component in the PTR that most easily affects the control o...

A. Razani C. Dodson T. Roberts

2010-01-01

453

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

Microsoft Academic Search

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

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

2002-01-01

454

33 CFR 157.164 - Use of inert gas system.  

Code of Federal Regulations, 2013 CFR

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

2013-07-01

455

The Migration and Coalescence of Inert Gas Bubbles in Metals  

Microsoft Academic Search

Thin copper films containing 0.1 atomic percent of helium, introduced by bombardment with 38 MeV alpha-particles, have been pulse-heated at ~ 800 ^circC in the electron microscope and the small helium bubbles which formed were observed and photographed after successive pulses. The bubbles could be seen to move through the copper with velocities ~ 1000 {circ}{ A}, exploding when they

R. S. Barnes; D. J. Mazey

1963-01-01

456

Temperature and gas-phase composition measurements in supersonic flows using tunable diode laser absorption spectroscopy: the effect of condensation on the boundary-layer thickness.  

PubMed

We used a tunable diode laser absorption spectrometer and a static-pressure probe to follow changes in temperature, vapor-phase concentration of D2O, and static pressure during condensation in a supersonic nozzle. Using the measured static-pressure ratio p/p0 and the mass fraction of the condensate g as inputs to the diabatic flow equations, we determined the area ratio (A/A*)wet and the corresponding centerline temperature of the flow during condensation. From (A/A*)wet we determined the boundary-layer displacement thickness during condensation (delta#)wet. We found that (delta#)wet first increases relative to the value of delta# in a dry expansion (delta#)Dry before becoming distinctly smaller than (delta#)Dry downstream of the condensation region. After correcting the temperature gradient across the boundary layers, the temperature determined from p/p0 and g agreed with the temperature determined by the laser-absorption measurements within our experimental error (+/-2 K), except when condensation occurred too close to the throat. The agreement between the two temperature measurements let us draw the following two conclusions. First, the differences in the temperature and mole fraction of D2O determined by the two experimental techniques, first observed in our previous study [P. Paci, Y. Zvinevich, S. Tanimura, B. E. Wyslouzil, M. Zahniser, J. Shorter, D. Nelson, and B. McManus, J. Chem. Phys. 121, 9964 (2004)], can be explained sufficiently by changes in delta# caused by the condensation of D2O, except when the phase transition occurs too close to the throat. Second, the extrapolation of the equation, which expresses the temperature dependence of the heat of vaporization of bulk D2O liquid, is a good estimate of the heat of condensation of supercooled D2O down to 210 K. PMID:16161570

Tanimura, Shinobu; Zvinevich, Yury; Wyslouzil, Barbara E; Zahniser, Mark; Shorter, Joanne; Nelson, David; McManus, Barry

2005-05-15

457

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

458

Condensation cleaning of particulate laden gases  

SciTech Connect

Particulate laden gas, especially those gases carrying particulates having a size in the micron or submicron range, are removed by humidifying the gas with water and thereafter subjecting the gas to indirect contact heat exchange sufficient to provide an energy transfer for water vapor condensation of at least 5 horsepower per 1000 cfm. Heat exchange is accomlished by passing the gas downwardly through an exchange element having smooth and vertical gas passages of a relatively large dimension.

Devries, E.

1981-08-18

459

Some Experimental Observations of Dropwise Condensation of Steam.  

National Technical Information Service (NTIS)

Using a tiltable steam condenser test section, the parametric effects of heat flux, non-condensable gas, promoter, condenser surface thermal resistance, and surface inclination were studied on a 3.18 mm thick flat copper plate and on 0.051 mm thick foils ...

J. L. Morgan

1977-01-01

460

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

SciTech Connect

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

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

1983-09-01

461

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

462

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

463

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

464

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

465

Inert grinding and direct firing in coal burning systems  

SciTech Connect

A system in which coal is ground and transported in an inert atmosphere to a place of burning which may be a rotary kiln or a furnace, and in which system the coal being ground is used as the medium to produce the drying and inerting while the transporting media is the air brought in from outside the system and treated in a heating unit to consume part of the normal oxygen so it is rendered inert by the time it circulates in the system as the transporting media.

Willams, R.M.

1980-10-07

466

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

467

Steam condenser developments  

NASA Astrophysics Data System (ADS)

Factors determining condenser size and tube arrangement are reviewed, including steam side pressure drop; incondensible blanketing; effect of incondensibles on heat transfer; vent requirements; deaeration; condensate depression; cooling water velocity; tube material and diameter selection; fouling; and enhanced heat transfer tubes. Tube nest shapes and condenser concepts are described. Thermal design, and condenser acceptance testing are treated; field test results on "Church Window'' condensers are reported.

Lang, H. V.

468

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

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

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

469

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

470

Direct condensation refrigerant recovery and restoration system  

SciTech Connect

This patent describes a refrigerant recovery and purification system for removing gaseous refrigerant from a disabled refrigeration unit, cleaning the refrigerant of contaminants, and converting the gaseous refrigerant to a liquid state for storage. It comprises a low pressure inlet section; a high pressure storage section; the low pressure inlet section comprising: an oil and refrigerant gas separator, including a separated oil removal means, first conduit means for connecting an inlet of the separator to the disabled refrigerant unit, a slack-sided accumulator, second conduit means connecting the separator to the slack-sided accumulator, a reclaim condenser, third conduit means connecting the separator and the reclaim condenser in series, an evaporator coil in the reclaim condenser connectable to a conventional operating refrigeration system for receiving a liquid refrigerant under pressure for expansion therein, the evaporator coil forming a condensing surface for condensing the refrigerant gas at near atmospheric pressure in the condenser, a liquid receiver, a reclaimed refrigerant storage tank, fourth conduit means further connecting the liquid receiver in series with the reclaim condenser, downstream thereof, means between the reclaim condenser and the liquid receiver.

Grant, D.C.H.

1992-03-10

471

Optimisation of inert matrix fuel concepts for americium transmutation  

Microsoft Academic Search

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

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

1999-01-01

472

Halon inerting as a hydrogen control measure for Sequoyah  

SciTech Connect

Halon inerting after accident initiation has been proposed as a hydrogen control measure for the Sequoyah nuclear plant containment building. We carried out a literature search and performed simple analyses in order to assess the pros and cons of using Halon and to develop a design concept for an inerting system. The most significant problem associated with Halon use in a nuclear plant appears to be decomposition of the Halon into corrosiv