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1

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

2

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

3

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

4

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

5

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

6

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

7

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

8

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

9

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

10

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

11

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

12

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

13

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

14

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

15

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

16

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

17

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

yvind Jelmert; Inger-Lise Hansteen; Sverre Langrd

1995-01-01

18

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

19

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

20

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

21

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

22

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

23

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

24

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

25

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

26

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

27

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

28

Beyond the dilute Bose gas  

NASA Astrophysics Data System (ADS)

We discuss problems of three dimensional Bose gases in interaction but non-dilute. We then use the theory of a weakly interacting Bose gas recently analyzed as an attempt to obtain further insights into non-dilute systems. In particular, we develop the theory with additional remarks, discussions and a slight modification. The article concludes with a much more detailed analysis of the Bose condensate depletion, as well as a study of the two-fluid model of Tisza and Landau: the coexistence of normal and superfluid liquids at sufficiently low temperatures. In fact, even if it is based on one debatable hypothesis, this non-dilute gas qualitatively leads, up to Landau's T law, to a rigorous derivation of most of the previous theoretical studies on liquid helium. It also provides new observations, such as, for example, the coexistence of four subsystems of linked pair of particles: a thermal quasi-particle gas, a frozen jelly, a mixture between the previous ones, and a non-conventional Bose condensation of Cooper-type pairs. Moreover, the entropic gas is shown to be different from Landau's form associated with the normal liquid.

Bru, Jean-Bernard

2006-01-01

29

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

30

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

31

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, Pter; Schrder, Volkmar

2005-05-20

32

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

33

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

34

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

35

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

36

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 models 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.; Pietra, Tanja; Behr, Volker C.

2005-12-01

37

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

38

Inert gas solubility in binary germaniasilica glasses  

Microsoft Academic Search

Helium and neon solubility have been measured in vitreous silica, vitreous germania, and in a series of binary GeO2SiO2 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

39

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

40

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

41

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

42

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

43

Drying of a Dilute Suspension in a Revolving Flow Fluidized Bed of Inert Particles  

Microsoft Academic Search

Revolving air flow was generated by oblique holes on air distribution board in a fluidized bed dryer. Such a revolving air flow shows a large scale velocity fluctuation in radial as well as tangential directions. This turbulent flow of air can fluidize the inert particles with superior performance than vibrated fluidized bed. The revolving fluidized bed is simpler in fabrication

Lijuan Zhao; Yongkang Pan; Jianguo Li; Guohua Chen; Arun S. Mujumdar

2004-01-01

44

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

45

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

46

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 300K under conditions of oil-free pumping.

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

1982-01-01

47

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

48

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

49

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

50

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

51

Coupling of exothermic and endothermic reactions in oxidative conversion of natural gas into ethylene\\/olefins over diluted SrO\\/LaO\\/SA5205 catalyst  

Microsoft Academic Search

In the oxidative conversion of natural gas to ethylene\\/lower olefins over SrO (17.3 wt.%)\\/LaO (17.9 wt.%)\\/SA5205 catalyst diluted with inert solid particles (inerts\\/catalyst(w\\/w) = 2.0) in the presence of limited O, the exothermic oxidative conversion reactions of natural gas are coupled with the endothermic C{sub 2+} hydrocarbon thermal cracking reactions for avoiding hot spot formation and eliminating heat removal problems.

Vasant R. Choudhary; Shafeek A. R. Mulla

1997-01-01

52

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

53

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

54

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

55

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

56

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

57

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

58

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

59

Test of dilute gas approximation in quantum mechanical model  

Microsoft Academic Search

The validity of dilute gas approximation is explored by making use of the large-sized instanton in quantum mechanical model. It is shown that the Euclidean probability amplitude derived through a dilute gas approximation not only cannot explain the result of the linear combination of atomic orbitals approximation, but also does not exhibit a proper limiting case when the size of

D. K. Park; Soo-Young Lee; Jae-Rok Kahng; Sahng-Kyoon Yoo; C. H. Lee; Chang Soo Park; Eui-Soon Yim

1996-01-01

60

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

61

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

62

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

63

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

64

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

65

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

66

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

67

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

68

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

69

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=11.60.4 nm) and ferromagnetic cobalt fluids (mean particle size=51.63.4 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

70

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

71

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

72

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

73

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 Bnard instabilities. It is assumed that the gas phase is perfectly mixed at some distance from the liquidgas interface (given composition, pressure, and temperature). If this distance is not much larger

Benot Haut; Pierre Colinet

2005-01-01

74

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

75

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

76

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 900C in a graphite crucible, followed by a subsequent gradual temperature increase of up to 2000C, 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

77

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

78

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

79

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

80

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

81

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

82

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. zdemir

2002-01-01

83

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 FeCoCrNiMox 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

84

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; Jos A. M. Ferreira; Carlos A. G. M. Branco

2011-01-01

85

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

86

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

Microsoft Academic Search

Several permanent magnet alloys based on the ternary NdFeB (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

87

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

88

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 (H), 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; Vladimr Dohnal

1997-01-01

89

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; Joo L. F. Azevedo; Heidi Korzenowski

2000-01-01

90

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

91

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

92

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 200C. 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

93

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

94

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

95

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

96

A Dilution System for Dynamic Preparation of Gas Concentrations  

Microsoft Academic Search

Construction details of a portable system for dynamic preparation of gas concentrations are described. Permeation or diffusion tubes are used for generating the required gases. House air passes through a heatless dryer to obtain pure dry air, prior to entering the system. Two dilution and two bleed stations, as well as a temperature-controlled oven, are provided to allow production of

J. H. BLACKER

1971-01-01

97

Entropy production and viscosity of a dilute gas  

NASA Astrophysics Data System (ADS)

It is known that the viscosity of a dilute gas can be derived by using kinetic theory. We present here a new derivation by using two entropy production principles: the steepest entropy ascent (SEA) principle and the maximum entropy production (MEP) principle. The known result is reproduced in a similar form.

Zhang, Yong-Jun

2012-06-01

98

A new gas dilution method for measuring body volume.  

PubMed Central

This study was designed to examine the validity of a new gas dilution method (GD) for measuring human body volume and to compare its accuracy with the results obtained by the underwater weighing method (UW). We measured the volume of plastic bottles and 16 subjects (including two females), aged 18-42 years with each method. For the bottles, the volume measured by hydrostatic weighing was correlated highly (r = 1.000) with that measured by the new gas dilution method. For the subjects, the body volume determined by the two methods was significantly correlated (r = 0.998). However, the subject's volume measured by the gas dilution method was significantly larger than that by underwater weighing method. There was significant correlation (r = 0.806) between GD volume-UW volume and the body mass index (BMI), so that UW volume could be predicted from GD volume and BMI. It can be concluded that the new gas dilution method offers promising possibilities for future research in the population who cannot submerge underwater.

Nagao, N; Tamaki, K; Kuchiki, T; Nagao, M

1995-01-01

99

Dilute Monopole Gas, and K-Tensions in Gluodynamics  

NASA Astrophysics Data System (ADS)

A dilute monopole gas explains, in quarkless gluodynamics, the small ratio ? between the square of magnetic screening mass mM and spatial Wilson loop tension. This ratio is 0.0895 for T = 0 to 0.0594 at T = ? for any number of colours with order N-2 corrections and equals up to a numerical factor of O(1) the diluteness. The monopoles have a size lM = m-1M. The GNO classification tells us they are in a representation of the magnetic SU(N) group. Choosing the adjoint for the dilute gas predicts the k-tensions to scale as k(N - k), within a percent for high T, and a few percent for low T for the seven ratios determined by lattice simulation. The transition is determined by the transition of the dilute Bose gas at Tc = 0.174mM, and the transition is that of a non- or nearly-relativistic Bose gas.

Altes, C. P. Korthals; Giovannangeli, P.

2005-01-01

100

Review - numerical models for dilute gas-particle flows  

Microsoft Academic Search

The significant nondimensional parameters relating to dilute gas-particle flows are defined, and a review of the essential features of gas-particle flows from the point of view of model development is presented. Also, the various models that have appeared for one-dimensional and two-dimensional flows are examined, and the advantages and disadvantages of the trajectory and two-fluid models are considered. It is

C. T. Crowe

1982-01-01

101

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

102

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

103

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

104

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

105

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

106

Entropy production and thermal conductivity of a dilute gas  

NASA Astrophysics Data System (ADS)

It is known that the thermal conductivity of a dilute gas can be derived by using kinetic theory. We present here a new derivation by starting with two known entropy production principles: the steepest entropy ascent (SEA) principle and the maximum entropy production (MEP) principle. A remarkable feature of the new derivation is that it does not require the specification of the existence of the temperature gradient. The known result is reproduced in a similar form.

Zhang, Yong-Jun

2011-05-01

107

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

108

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

109

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

110

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

111

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

112

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

113

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

114

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

115

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

116

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

117

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

118

Monte Carlo Simulation of Wave Damping in a Dilute Gas  

NASA Astrophysics Data System (ADS)

A computer simulation has been written that simulates the evolution of a perturbed dilute gas using the Direct-Simulation Monte Carlo method, with the ultimate goal of adding collisions to a simulation of ultra-cold plasmas. As a test, it has been used to study fluid dynamic affects in one dimension using a small velocity perturbation so that comparison with standard gas-dynamic theory is possible. This comparison has been used to investigate the limitations on certain simulation parameters such as cell size, size of each time step, number of simulation particles, and mean-free-path. The simulation and the theory agree well when the mean-free path is a small fraction of the sound wavelength, but for long mean free paths the simulation and the theory diverge. As an illustration, the famous ``bell in a bell jar'' demonstration will be examined to see if wave damping might play a role.

Clary, Ryan; Spencer, Ross

2003-10-01

119

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

120

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

121

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

122

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, Joo L. F.; Korzenowski, Heidi

2000-05-01

123

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

124

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

125

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

126

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

127

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

128

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

129

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

130

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

131

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

132

In situ production of FeTiC 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 FeCrBSi 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

133

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

134

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 (CClF--CF) into the water inlet ; of a condenser suspected of leaking

1958-01-01

135

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

136

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

137

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

138

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

139

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. Gk

2011-01-01

140

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

141

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

142

Effects of oxygen cover gas and NaOH dilution on gas generation in tank 241-SY-101 waste  

SciTech Connect

Laboratory studies are reported of gas generation in heated waste from tank 241-SY-101. The rates of gas generation and the compositions of product gas were measured. Three types of tests are compared. The tests use: undiluted waste, waste diluted by a 54% addition of 2.5 M NaOH, and undiluted waste with a reactive cover gas of 30% Oxygen in He. The gas generation rate is reduced by dilution, increased by higher temperatures (which determines activation energies), and increased by reactions of Oxygen (these primarily produce H{sub 2}). Gases are generated as reduction products oxidation of organic carbon species by nitrite and oxygen.

Person, J.C.

1996-05-30

143

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

144

Viscosity increase upon spin polarization of a dilute Fermi gas  

Microsoft Academic Search

A vibrating-wire technique has been used to directly measure the viscosity increase in a dilute 3-4He solution caused by brute-force spin polarization up to 40%. The viscosity of a solution with degeneracy temperature TF=19.5 mK was measured over the temperature range 6.1-100 mK in magnetic fields of 1.00 and 7.96 T. Spin polarization caused a marked decrease in the mechanical

D. Candela; L.-J. Wei; D. R. McAllaster; W. J. Mullin

1991-01-01

145

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

146

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

147

Viscosity increase upon spin polarization of a dilute Fermi gas  

Microsoft Academic Search

A vibrating-wire technique has been used to directly measure the viscosity increase in a dilute ³He-⁴He solution caused by brute-force spin polarization up to 40%. The viscosity of a solution with degeneracy temperature {ital T}{sub {ital F}}=19.5 mK was measured over the temperature range 6.1--100 mK in magnetic fields of 1.00 and 7.96 T. Spin polarization caused a marked decrease

D. Candela; L. J. Wei; D. R. McAllaster; W. J. Mullin

1991-01-01

148

Headspace gas chromatography for measurement of infinite dilution activity coefficients of C 4 alcohols in water  

Microsoft Academic Search

For environmental and other reasons, there is interest in determining values of infinite dilution activity coefficients (??) of organic solutes in volatile solvents, particularly in water. Here, we present a detailed description of a headspace gas chromatograph recently constructed for the measurement of infinite dilution activity coefficients and report values of ?? for 1-butanol, 2-butanol, 2-methyl-1-propanol (iso-butanol) and 2-methyl-2-propanol (tert-butanol)

Paul G Whitehead; Stanley I Sandler

1999-01-01

149

The physics of trapped dilute-gas BoseEinstein condensates  

Microsoft Academic Search

The experimental realisation of BoseEinstein 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 BoseEinstein 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

150

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

151

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

152

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

153

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

154

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

155

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

156

Pore formation during hybrid laser-tungsten inert gas arc welding of magnesium alloy AZ31Bmechanism 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

157

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

158

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

159

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

160

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

161

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; Joo da C. Payo Filho

2011-01-01

162

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 0.40.8% vol. for a specific crude supply rate of 30005000 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

163

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

164

Investigating the Potential Dilution of the Metal Content of Hot Gas in Early-type Galaxies by Accreted Cold Gas  

NASA Astrophysics Data System (ADS)

The measured emission-weighted metal abundance of the hot gas in early-type galaxies has been known to be lower than theoretical expectations for 20 years. In addition, both X-ray luminosity and metal abundance vary significantly among galaxies of similar optical luminosities. This suggests some missing factors in the galaxy evolution process, especially the metal enrichment process. With Chandra and XMM-Newton, we studied 32 early-type galaxies (kT <~ 1 keV) covering a span of two orders of L X, gas/LK to investigate these missing factors. Contrary to previous studies that X-ray faint galaxies show extremely low Fe abundance (~0.1 Z ?), nearly all galaxies in our sample show an Fe abundance at least 0.3 Z ?, although the measured Fe abundance difference between X-ray faint and X-ray bright galaxies remains remarkable. We investigated whether this dichotomy of hot gas Fe abundances can be related to the dilution of hot gas by mixing with cold gas. With a subset of 24 galaxies in this sample, we find that there is virtually no correlation between hot gas Fe abundances and their atomic gas content, which disproves the scenario that the low metal abundance of X-ray faint galaxies might be a result of the dilution of the remaining hot gas by pristine atomic gas. In contrast, we demonstrate a negative correlation between the measured hot gas Fe abundance and the ratio of molecular gas mass to hot gas mass, although it is unclear what is responsible for this apparent anti-correlation. We discuss several possibilities including that externally originated molecular gas might be able to dilute the hot gas metal content. Alternatively, the measured hot gas Fe abundance may be underestimated due to more complex temperature and abundance structures and even a two-temperature model might be insufficient to reflect the true value of the emission weighted mean Fe abundance.

Su, Yuanyuan; Irwin, Jimmy A.

2013-03-01

165

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

166

A van der Waals Equation of State for a Dilute Boson Gas  

ERIC Educational Resources Information Center

|An equation of state of a system is a relationship that connects the thermodynamic variables of the system such as pressure and temperature. Such equations are well known for classical gases but less so for quantum systems. In this paper we develop a van der Waals equation of state for a dilute boson gas that may be used to explain the occurrence

Deeney, F. A.; O'Leary, J. P.

2012-01-01

167

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

Microsoft Academic Search

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

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

168

Dilute Monopole Gas, Magnetic Screening and K-Tensions in Hot Gluodynamics  

NASA Astrophysics Data System (ADS)

A dilute monopole gas explains, in quarkless gluodynamics, the small ratio ? between the square of magnetic screening mass mM and spatial Wilson loop tension. This ratio is 0.0895 for T = 0 to 0.0594 at T = ? for any number of colours with order N-2 corrections and equals up to a numerical factor of O(1) the diluteness. The monopoles have a size lM = mM{ - 1} . The GNO classification tells us they are in a representation of the magnetic SU(N) group. Choosing the adjoint for the dilute gas predicts the k-tensions to scale as k(N - k), within a percent for high T, and a few percent for low T for the seven ratios determined by lattice simulation. The transition is determined by the transition of the dilute Bose gas at Tc = 0.174mM, and the transition is that of a non- or nearly-relativistic Bose gas.

Korthals Altes, C. P.

2004-11-01

169

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

170

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

171

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

172

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

173

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

174

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

175

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

176

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

177

Stability Characteristics of Turbulent Hydrogen Dilute Diffusion Flames  

Microsoft Academic Search

Diffusion flame combustion of high-hydrogen fuels in land-based gas turbine combustors may include dilution of the fuel with inert gases and high velocity fuel injection to reduce NOx emissions. Stability regimes of such combustors are investigated in this study by examining turbulent dilute diffusion flames of hydrogen\\/nitrogen mixtures, issuing into a quiescent environment from a thin-lipped tube. This study has

Nathan T. Weiland; Peter A. Strakey

2009-01-01

178

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

179

Brazability of dissimilar metals tungsten inert gas butt weldingbrazing between aluminum alloy and stainless steel with AlCu filler metal  

Microsoft Academic Search

Dissimilar metals tungsten inert gas butt weldingbrazing between 5A06 aluminum alloy and SUS321 stainless steel was carried out using AlCu6 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 35?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

180

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

181

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. Shkolnik

1997-01-01

182

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

183

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

184

High-accuracy stable gas flow dilution using an internally calibrated network of critical flow orifices  

Microsoft Academic Search

A network of critical flow orifices has been developed to form a gas flow dilutor capable of stable and repeatable operation, which is not influenced by environmental conditions. When used with a novel self-calibration method it achieves dilutions of up to 31:1 with a relative standard uncertainty of 0.1%. This new approach avoids the uncertainty generated by setting and controlling

P. J. Brewer; B. A. Goody; T. Gillam; R. J. C. Brown; M. J. T. Milton

2010-01-01

185

The Ground State Energy of a Dilute Two-dimensional Bose Gas  

Microsoft Academic Search

The ground state energy per particle of a dilute, homogeneous, two-dimensional Bose gas, in the thermodynamic limit is shown rigorously to be $E_0\\/N = (2\\\\pi \\\\hbar^2\\\\rho \\/m){|\\\\ln (\\\\rho a^2)|^{-1}}$, to leading order, with a relative error at most ${\\\\rm O} (|\\\\ln (\\\\rho a^2)|^{-1\\/5})$. Here $N$ is the number of particles, $\\\\rho =N\\/V$ is the particle density and $a$ is the

Elliott H. Lieb; Jakob Yngvason

2000-01-01

186

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

NASA Astrophysics Data System (ADS)

The energy and structure of a dilute hard-disks Bose gas are studied in the framework of a variational many-body approach based on a Jastrow correlated ground-state wave function. The asymptotic behaviors of the radial distribution function and the one-body density matrix are analyzed after solving the Euler equation obtained by a free minimization of the hypernetted chain energy functional. Our results show important deviations from those of the available low density expansions, already at gas parameter values xtilde 0.001 . The condensate fraction in 2D is also computed and found generally lower than the 3D one at the same x .

Mazzanti, F.; Polls, A.; Fabrocini, A.

2005-03-01

187

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

SciTech Connect

The energy and structure of a dilute hard-disks Bose gas are studied in the framework of a variational many-body approach based on a Jastrow correlated ground-state wave function. The asymptotic behaviors of the radial distribution function and the one-body density matrix are analyzed after solving the Euler equation obtained by a free minimization of the hypernetted chain energy functional. Our results show important deviations from those of the available low density expansions, already at gas parameter values x{approx}0.001. The condensate fraction in 2D is also computed and found generally lower than the 3D one at the same x.

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

2005-03-01

188

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

189

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

190

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

191

Bulk Viscosity and Conformal Symmetry Breaking in the Dilute Fermi Gas near Unitarity  

NASA Astrophysics Data System (ADS)

The dilute Fermi gas at unitarity is scale invariant and its bulk viscosity vanishes. We compute, in the high temperature limit, the leading contribution to the bulk viscosity when the scattering length is not infinite. A measure of scale breaking is provided by the ratio (P-2/3E)/P, where P is the pressure and E is the energy density. At high temperature this ratio scales as z?/a, where z is the fugacity, ? is the thermal wavelength, and a is the scattering length. We show that the bulk viscosity ? scales as the second power of this parameter, ?(z?/a)2?-3.

Dusling, Kevin; Schfer, Thomas

2013-09-01

192

Bulk Viscosity and Conformal Symmetry Breaking in the Dilute Fermi Gas near Unitarity.  

PubMed

The dilute Fermi gas at unitarity is scale invariant and its bulk viscosity vanishes. We compute, in the high temperature limit, the leading contribution to the bulk viscosity when the scattering length is not infinite. A measure of scale breaking is provided by the ratio (P-2/3E)/P, where P is the pressure and E is the energy density. At high temperature this ratio scales as z?/a, where z is the fugacity, ? is the thermal wavelength, and a is the scattering length. We show that the bulk viscosity ? scales as the second power of this parameter, ??(z?/a)^{2}?^{-3}. PMID:24093239

Dusling, Kevin; Schfer, Thomas

2013-09-19

193

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

SciTech Connect

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

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

2008-01-01

194

Computational modeling of dilute gas-particle flows in an ultrasonic gas flowmeter  

Microsoft Academic Search

A computational procedure is presented to predict particle-laden turbulent gas flows in an ultrasonic flowmeter using curvilinear coordinates. The Eulerian-Lagrangian hybrid model is used for the two-phase flow predictions. The turbulent gas phase is formulated using the Eulerian governing equations whereas the particle phase is formulated using the Lagrangian governing equations. The effect of the gas turbulence on discrete particle

X.-Q. Chen; J. C. F. Pereira

1998-01-01

195

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.; Pron, F.; Lacquement, J.

2007-01-01

196

Itinerant ferromagnetism in a Fermi gas with contact interaction: Magnetic properties in a dilute Hubbard model  

NASA Astrophysics Data System (ADS)

Ground-state properties of the repulsive Hubbard model on a cubic lattice are investigated by means of the auxiliary-field quantum Monte Carlo method. We focus on low-density systems with varying on-site interaction U/t, as a model relevant to recent experiments on itinerant ferromagnetism in a dilute Fermi gas with contact interaction. Twist-average boundary conditions are used to eliminate open-shell effects and large lattice sizes are studied to reduce finite-size effects. The sign problem is controlled by a generalized constrained path approximation. We find no ferromagnetic phase transition in this model. The ground-state correlations are consistent with those of a paramagnetic Fermi liquid.

Chang, Chia-Chen; Zhang, Shiwei; Ceperley, David M.

2010-12-01

197

Dissipative fluid dynamics for the dilute Fermi gas at unitarity: Free expansion and rotation  

SciTech Connect

We investigate the expansion dynamics of a dilute Fermi gas at unitarity in the context of dissipative fluid dynamics. Our aim is to quantify the effects of shear viscosity on the time evolution of the system. We compare exact numerical solutions of the equations of viscous hydrodynamics to various approximations that have been proposed in the literature. Our main findings are (i) shear viscosity leads to characteristic features in the expansion dynamics; (ii) a quantitative description of these effects has to include reheating; (iii) dissipative effects are not sensitive to the equation of state P(n,T) as long as the universal relation P=(2/3)E is satisfied; (iv) the expansion dynamics mainly constrains the cloud average of the shear viscosity.

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

2010-12-15

198

Optimization in multidimensional gas chromatography applying quantitative analysis via a stable isotope dilution assay.  

PubMed

Trace level analyses in complex matrices benefit from heart-cut multidimensional gas chromatographic (MDGC) separations and quantification via a stable isotope dilution assay. Minimization of the potential transfer of co-eluting matrix compounds from the first dimension ((1)D) separation into the second dimension separation requests narrow cut-windows. Knowledge about the nature of the isotope effect in the separation of labeled and unlabeled compounds allows choosing conditions resulting in at best a co-elution situation in the (1)D separation. Since the isotope effect strongly depends on the interactions of the analytes with the stationary phase, an appropriate separation column polarity is mandatory for an isotopic co-elution. With 3-alkyl-2-methoxypyrazines and an ionic liquid stationary phase as an example, optimization of the MDGC method is demonstrated and critical aspects of narrow cut-window definition are discussed. PMID:23732869

Schmarr, Hans-Georg; Slabizki, Petra; Legrum, Charlotte

2013-06-04

199

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

SciTech Connect

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

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

2011-07-15

200

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

201

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

202

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

203

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

204

[Determination of indicator toxaphene in soil by isotope dilution-gas chromatography-tandem mass spectrometry].  

PubMed

Although toxaphene is now banned in use, the analysis of toxaphene has attracted increasing interest due to its persistence and widespread atmospheric transport in the environment. A new method based on isotope dilution-gas chromatography-tandem mass spectrometry (ID-GC-MS/MS) has been developed for the determination of three toxaphene specific congeners comprised of Parlar No. 26 (P26), Parlar No. 50 (P50) and Parlar No. 62 (P62) in soil. (13)C10-labeled indicator toxaphene solution was added to the sample prior to pretreatment. Then the sample was extracted using pressurized liquid extraction (PLE) followed by purification on multilayer acidic silica column and neutral silica column. The eluent was concentrated under gentle nitrogen gas flow and spiked with the injection of internal standard of (13)C10-chlordane. Identification and quantification of the analytes were carried out in the multiple reaction monitoring (MRM) mode after the GC separation. The linear range was 20-800 microg/L for three congeners, limits of detection (LOD) ranged from 3.0 to 6.0 pg. The five point calibration curves showed a good linearity for all the congeners (R2 > 0.99). The relative standard deviations (RSDs) were below 11% for and the spiked recoveries were in the range of 55%-110%. The developed analytical method is suitable for the determination of toxaphene specific congeners in soil. PMID:20812620

Zhang, Bing; Wu, Jiajia; Liu, Guorui; Gao, Lirong; Zheng, Minghui

2010-05-01

205

Lung volume measurements in wheezy infants: comparison of plethysmography and gas dilution.  

PubMed

The accuracy both of plethysmographic measurements of thoracic gas volume (TGV) and determinations of functional residual capacity (FRC) by gas dilution techniques in infants with obstructive lung disease is subject to continued dispute. We studied 25 wheezy infants and compared TGV derived from end-expiratory airway occlusions (TGVEE), corrected TGV after end-inspiratory airway occlusions (TGVEI), and FRC determined by nitrogen wash-out (FRCN2). Group mean TGVEE and TGVEI differed significantly (25.8 +/- 8.4 versus 24.6 +/- 7.1 ml.kg-1). TGVEE and FRCN2 did not differ significantly. TGVEE and TGVEI, as well as TGVEE and FRCN2, and TGVEI and FRCN2 data, respectively, showed lack of agreement. Based on 95% confidence intervals, calculated from TGVEE data, 14 of the 25 infants showed a significantly higher TGVEI than TGVEE; only one patient had a significantly lower TGVEI. Compared to FRCN1 data, TGVEE and TGVEI measurements yielded lower values in at least one third of our patients. The present study illustrates, that there is no gold standard for the measurement of lung volume in infants with airway obstruction. PMID:7875270

Eber, E; Steinbrugger, B; Modl, M; Weinhandl, E; Zach, M S

1994-11-01

206

IMPACT OF GROWING ENVIRONMENT ON CHICKASAW BLACKBERRY (RUBUS L.) AROMA EVALUATED BY GAS CHROMATOGRAPHY OLFACTOMETRY DILUTION ANALYSIS  

Technology Transfer Automated Retrieval System (TEKTRAN)

The aroma extract of Chickasaw blackberry ( RubusL.) was separated with silica gel normal phase chromatography into six fractions. Gas chromatography-olfactometry (GCO) was performed on each fraction to identify aroma active compounds. Aroma extraction dilution analysis (AEDA) was employed to charac...

207

Dilution refrigerator to obtain polarized liquid 3He below 200 mK starting from optically oriented gas  

Microsoft Academic Search

We describe the design and construction of a dilution refrigerator to obtain polarized liquid 3He in the degenerate region by liquifying and cooling optically pumped gas. This apparatus will extend the temperature region accessible with a 3He cryostat for the study of polarized 3He in our group (1). To establish thermal contact between the mixing chamber and the sample we

Gerard Vermeulen; Myriam Cornut

1990-01-01

208

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

209

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

210

[Determination of trace organochlorine pesticides in soil using isotope dilution-high resolution gas chromatography].  

PubMed

A method for the determination of trace organochlorine pesticides (OCPs) in soil using isotope dilution and high resolution gas chromatography-high resolution mass spectrometry (ID-HRGC-HRMS) was developed. The sample was extracted by accelerated solvent extractor (ASE) and cleaned-up by a Florisil solid phase extraction (SPE) cartridge. The analytes were separated by HRGC on a DB-5MS column (30 mx 0.25 mm x 0.25 microm) and determined by HRMS. The identifications of OCPs were based on the retention time of 13C-labelled standard and the abundance ratio of the two exact mass-to-charge ratios. The quantitative analysis was performed using the ratios of the integrated areas of the 13C-labelled standards. This method has the recoveries ranging from 77.3% to 114.5% and the relative standard deviations (RSD) less than 10.81% (n=5). The limits of detection (LODs) of this method for all OCPs were lower than 0.04 pg/g. The results indicated that the method is rapid, selective and sensitive for precise determination requirements of organochlorine pesticides at trace level in soil. PMID:20812621

Huang, Wenjun; Gao, Lirong; Gong, Aijun; Li, Cheng; Wang, Pu; Fu, Shan; Xiao, Ke; Zhang, Bing; Liu, Wenbin

2010-05-01

211

Mixed aqueous solutions as dilution media in the determination of residual solvents by static headspace gas chromatography.  

PubMed

Static headspace (HS) sampling has been commonly used to test for volatile organic chemicals, usually referred to as residual solvents (RS) in pharmaceuticals. If the sample is not soluble in water, organic solvents are used. However, these seriously reduce the sensitivity in the determination of some RS. Here, mixed aqueous dilution media (a mixture of water and an organic solvent like dimethyl formamide, dimethyl sulfoxide or dimethyl acetamide) were studied as alternative media for static HS-gas chromatographic analysis. Although it has been known that mixed aqueous dilution media can often improve sensitivity for many RS, this study used a systematic approach to investigate phase volumes and the organic content in the HS sampling media. Reference solutions using 18 different class 1, 2 and 3 RS were evaluated. The effect of salt addition was also studied in this work. A significant increase in the peak area was observed for all RS using mixed aqueous dilution media, when compared with organic solvents alone. Matrix effects related to the mixed aqueous dilution media were also investigated and reported. Repeatability and linearity obtained with mixed aqueous dilution media were found to be similar to those observed with pure organic solvents. PMID:21538876

D'Autry, Ward; Zheng, Chao; Wolfs, Kris; Yarramraju, Sitaramaraju; Hoogmartens, Jos; Van Schepdael, Ann; Adams, Erwin

2011-04-27

212

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

SciTech Connect

The surface thermodynamic properties of three main inorganic compounds formed during hydration of Portland cement: calcium hydroxide (Ca(OH){sub 2}), ettringite (3CaO.Al{sub 2}O{sub 3}.3CaSO{sub 4}.32H{sub 2}O) and calcium-silicate-hydrates (C-S-H), respectively, and one mineral filler: calcium carbonate (CaCO{sub 3}), have been characterised by inverse gas chromatography at infinite dilution (IGC-ID) at 35 deg. C. The thermodynamic properties have been investigated using a wide range of non-polar (n-alkane series), Lewis acidic (CH{sub 2}Cl{sub 2} and CHCl{sub 3}), Lewis basic (diethyl ether) and aromatic (benzene) and n-alkene series molecular probes, respectively. The tested samples are fairly high surface energy materials as judged by the high dispersive contribution to the total surface energy (the dispersive components {gamma} {sub s} {sup d} range from 45.6 up to 236.2 mJ m{sup -2} at 35 deg. C) and exhibit amphoteric properties, with a predominant acidic character. In the case of hydrated components (i.e. ettringite and C-S-H), the surface thermodynamic properties have been determined at various temperatures (from 35 up to 120 deg. C) in order to examine the influence of the water content. The changes of both dispersive and specific components clearly demonstrate that the material surface properties are activated with temperature. The changes in the acid-base properties are correlated with the extent of the overall water loss induced by the thermal treatment as demonstrated by thermogravimetric analysis (TGA). The elemental surface composition of these compounds has been determined by X-ray photoelectron spectroscopy (XPS)

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

2006-02-15

213

Gas chromatographic measurements of activity coefficients at infinite dilution for refrigerants with a polyol ester oil as a stationary phase  

Microsoft Academic Search

Activity coefficients at infinite dilution have been measured by gas chromatography for 14 refrigerants (R12, R22, R32, R124, R125, R134a, R142b, R143a, RE170, R236ea, R290, R600, R600a, and R236fa) as solutes, using a polyol ester oil (POE), EMKARATE by ICI, as a stationary phase (solvent). Instrumental analysis (NMR, IR) showed that the main components of the oil are pentaerithritol esters

Roman Stryjek; Sergio Bobbo; Roberto Camporese; Claudio Zilio

1999-01-01

214

Isotope dilution determination of polycyclic aromatic hydrocarbons in olive pomace oil by gas chromatographymass spectrometry  

Microsoft Academic Search

A gas chromatographic (GC) method with mass spectrometry detection (MS) for the determination of eight polycyclic aromatic hydrocarbons (PAHs) in olive pomace oil has been developed. The oil was diluted with n-pentane and extracted by liquidliquid partition with dimethyl sulphoxide (DMSO). After water addition and back-extraction with cyclohexane, a thin-layer chromatography on silica gel was performed as a further purification

Gianfranco Diletti; Giampiero Scortichini; Rossana Scarpone; Giuseppe Gatti; Luigi Torreti; Giacomo Migliorati

2005-01-01

215

Measurement of infinite-dilution activity coefficients of alcohols in water using relative gas-liquid chromatographic method  

Microsoft Academic Search

Infinite-dilution activity coefficients of n-alcohols (C1-C8) in water were measured by using the relative gas-liquid chromatographic method proposed by Orbey and Sandler [1991]. The\\u000a temperature range of measurement was 298 to 343 K. The g ?? values at 298.15 K varied from 1.72 (methanol) to 1970 (n-heptanol). ASOG, UNIFAC, modified UNIFAC (Dortmund), modified UNIFAC\\u000a (Lyngby) group contribution methods could predict

Katsumi Tochigi; Masanori Uchiyama; Kazuo Kojima

2000-01-01

216

RESEARCH ARTICLE Coupled-cluster theory of a gas of strongly-interacting fermions in the dilute limit  

Microsoft Academic Search

We study the ground-state properties of a dilute gas of strongly-interacting fermions in the framework of the coupled-cluster expansion (CCE). We demonstrate that properties such as universality, opening of a gap in the excitation spectrum and applicability of s-wave approx- imations appear naturally in the CCE approach. In the zero-density limit, we show that the ground-state energy density depends on

Bogdan Mihaila; Andres Cardenas

217

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

218

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

2013-06-01

219

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

220

Coupling of exothermic and endothermic reactions in oxidative conversion of natural gas into ethylene/olefins over diluted SrO/La{sub 2}O{sub 3}/SA5205 catalyst  

SciTech Connect

In the oxidative conversion of natural gas to ethylene/lower olefins over SrO (17.3 wt.%)/La{sub 2}O{sub 3} (17.9 wt.%)/SA5205 catalyst diluted with inert solid particles (inerts/catalyst(w/w) = 2.0) in the presence of limited O{sub 2}, the exothermic oxidative conversion reactions of natural gas are coupled with the endothermic C{sub 2+} hydrocarbon thermal cracking reactions for avoiding hot spot formation and eliminating heat removal problems. Because of this, the process is operated in the most energy-efficient and safe manner. The influence of various process variables (viz. temperature, NG/O{sub 2} and steam/NG ratios in feed, and space velocity) on the conversion of carbon and also of the individual hydrocarbons in natural gas, the selectivity for C{sub 2}-C{sub 4} olefins, and also on the net heat of reactions in the process has been thoroughly investigated. By carrying out the process at 800--850 C in the presence of steam (H{sub 2}O/NG {le} 0.2) and using limited O{sub 2} in the feed (NG/O{sub 2} = 12--18), high selectivity for ethylene (about 60%) or C{sub 2}-C{sub 4} olefins (above 80%) at the carbon conversion (>15%) of practical interest could be achieved at high space velocity ({ge}34,000 cm{sup 3}/g (catalyst) h), requiring no external energy and also without forming coke or tar-like products. The net heat of reactions can be controlled and the process can be made mildly exothermic or even close to thermoneutral by manipulating the O{sub 2} concentration in the feed.

Choudhary, V.R.; Mulla, S.A.R. [National Chemical Lab., Pune (India). Chemical Engineering Div.

1997-09-01

221

Simultaneous determination of mono-, di-, and tributyltin in sediments by isotope dilution analysis using gas chromatography--ICPMS.  

PubMed

A mixed spike containing 119Sn-enriched monobutyltin (MBT), dibutyltin (DBT), and tributyltin (TBT) was prepared by direct butylation of 119Sn-enriched tin metal using a 1:3 molar excess of butyl chloride with iodide and triethylamine as catalysts. The isotopic composition of the different tin species in the spike solution was determined by gas chromatography- ICPMS after aqueous ethylation using sodium tetraethylborate. Reverse isotope dilution analysis was used for the characterization of the spike by means of natural MBT, DBT, and TBT standards. No species transformation was evident during derivatization from the reverse isotope dilution experiments based on the measured isotope ratios both before and after spiking. The mixed spike was applied to the simultaneous analysis of MBT, DBT, and TBT in certified reference materials, PACS-2 and CRM 646, with satisfactory results. PMID:11467570

Encinar, J R; Villar, M I; Santamara, V G; Alonso, J I; Sanz-Medel, A

2001-07-01

222

EFFICIENCY OF GAS-WALL REACTIONS IN A CYLINDRICAL FLOW REACTOR  

EPA Science Inventory

Expressions are given for the concentration of a dilute reactive gas mixed with an inert carrier gas as a function of the radial and longitudinal distances in a cylindrical reactor and the reaction efficiency. The reaction efficiency is defined as the fraction of gas-wall collisi...

223

Gas chromatographic measurements of activity coefficients at infinite dilution for refrigerants with a polyol ester oil as a stationary phase  

SciTech Connect

Activity coefficients at infinite dilution have been measured by gas chromatography for 14 refrigerants (R12, R22, R32, R124, R125, R134a, R142b, R143a, RE170, R236ea, R290, R600, R600a, and R236fa) as solutes, using a polyol ester oil (POE), EMKARATE by ICI, as a stationary phase (solvent). Instrumental analysis (NMR, IR) showed that the main components of the oil are pentaerithritol esters of carboxylic acids, and electrospray ionization spectrometry revealed an average molecular mass of the POE of 618 g/mol. The measurements were performed within a temperature range of 244 K to 313 K, but a specific temperature range for each refrigerant was adopted depending on its retention data. The experimental findings are well-represented by the equation: ln {gamma}{sub i}{sup {infinity}} = a{sub i} {minus} b{sub i}/T. Some refrigerants, i.e., R22, R124, R125, R236ea, and R236fa, show quite a considerable positive temperature dependence of their activity coefficients at infinite dilution, which can be attributed to hydrogen bonding with the POE, unlike other refrigerants that show a small, either positive or negative temperature dependence. To the authors` knowledge, there are no data in the literature on activity coefficients at infinite dilution for refrigerant and oil (lubricant) systems, and details on the solubility of refrigerants in oils are also extremely scarce.

Stryjek, R. [Polish Academy of Sciences, Warsaw (Poland). Inst. of Physical Chemistry; Bobbo, S.; Camporese, R. [National Research Council, Padova (Italy). Inst. of Refrigeration; Zilio, C. [Univ. di Padova (Italy). Dept. di Fisica Tecnica

1999-05-01

224

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

Microsoft Academic Search

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

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

1997-01-01

225

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

Microsoft Academic Search

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

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

1996-01-01

226

Efficient gas-separation process to upgrade dilute methane stream for use as fuel  

Microsoft Academic Search

A membrane-based gas separation process for treating gas streams that contain methane in low concentrations. The invention involves flowing the stream to be treated across the feed side of a membrane and flowing a sweep gas stream, usually air, across the permeate side. Carbon dioxide permeates the membrane preferentially and is picked up in the sweep air stream on the

Johannes G. Wijmans; Timothy C. Merkel; Haiqing Lin; Scott Thompson; Ramin Daniels

2012-01-01

227

Constraining the volatility distribution and gas-particle partitioning of combustion aerosols using isothermal dilution and thermodenuder measurements.  

PubMed

The gas-particle partitioning of primary organic aerosol (POA) emissions from a diesel engine and the combustion of hard- and soft-woods in a stove was investigated by isothermally diluting them in a smog chamber or by passing them through a thermodenuder and measuring the extent of evaporation. The experiments were conducted at atmospherically relevant conditions: low concentrations and small temperature perturbations. The partitioning of the POA emissions from both sources varied continuously with changing concentration and temperature. Although the POA emissions are semivolatile, they do not completely evaporate at typical atmospheric conditions. The overall partitioning characteristics of diesel and wood smoke POA are similar, with wood smoke being somewhat less volatile than the diesel exhaust. The gas-particle partitioning of aerosols formed from flash-vaporized engine lubricating oil was also studied; diesel POA is somewhat more volatile than the oil aerosol. The experimental data from the dilution- and thermodenuder-based techniques were fit using absorptive partitioning theory to derive a volatility distribution of the POA emissions from each source. These distributions are suitable for use in chemical transport models that simulate POA concentrations. PMID:19673261

Grieshop, Andrew P; Miracolo, Marissa A; Donahue, Niel M; Robinson, Allen L

2009-07-01

228

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

229

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

230

Dilution-Based Emissions Sampling from Stationary Sources: Part 2Gas-Fired Combustors Compared with Other Fuel-Fired Systems  

Microsoft Academic Search

With the recent focus on fine particle matter (PM2.5),new, self-consistent data are needed to characterize emissions from combustion sources. Such data are necessary for health assessment and air quality modeling. To address this need, emissions data for gas-fired combustors are presented here, using dilution sampling as the reference.The dilution method allows for collection of emitted particles under conditions simulating cooling

Glenn C. England; John G. Watson; Judith C. Chow; Barbara Zielinska; M.-C. Oliver Chang; Karl R. Loos; George M. Hidy

2007-01-01

231

EFFECTS OF H2O AND CO2 DILUTION ON THE CATALYTIC AND GAS-PHASE COMBUSTION OF METHANE OVER PLATINUM AT ELEVATED PRESSURES  

Microsoft Academic Search

The impact of large exhaust gas dilution (up to 59.5% H2O and 30.3% CO2 per vol.) on the heterogeneous (catalytic) and homogeneous (gas-phase) steady combustion of fuel-lean CH4\\/O2\\/N2 mixtures over platinum has been investigated experimentally and numerically at pressures of 5 to 14 bar. In situ, one-dimensional Raman measurements of major gas-phase species concentrations and planar laser induced fluorescence (LIF)

MICHAEL REINKE; JOHN MANTZARAS; ROLF BOMBACH; SABINE SCHENKER; NICLAS TYLLI; KONSTANTINOS BOULOUCHOS

2007-01-01

232

Application of isotopically labeled methylmercury for isotope dilution analysis of biological samples using gas chromatography/ICPMS.  

PubMed

An isotope dilution (ID) procedure for the determination of methylmercury (MMHg) in biological samples using an inductively coupled plasma mass spectrometer as detector after the capillary gas chromatographic separation (CGC/ICPMS) has been developed. For the first time, open-focused-microwave pretreatment has been used in conjunction with ID. Optimum conditions for the measurement of isotope ratios on the fast transient chromatographic peaks have been established. Mass bias was found to be about 1.5%/mass unit and was corrected by using the simultaneously measured thallium signals at 203Tl and 205Tl. After mass-bias correction, deviation of the theoretical mercury ratio values was found to be as low as 0.2%. Isotope ratio precisions based on the peak areas measurements were 0.3% RSD for 20 pg injected (as Hg absolute). The absolute detection limits were in the range of 20-30 fg for 202Hg and 201Hg. Methylmercury enriched in 201Hg has been synthesized by direct reaction with methylcobalamine. The concentration of the MMHg spike has been measured by reverse isotope dilution with a natural MMHg standard. The capabilities of CGC/ICPMS to measure isotope ratios were used to optimize sample derivatization by aqueous ethylation with NaBEt4 with respect to MMHg degradation pathways and quantitative recovery. The accuracy of the method developed has been validated with biological certified reference materials (CRM-463, DORM-1). PMID:12069230

Rodriguez Martn-Doimeadios, R C; Krupp, E; Amouroux, D; Donard, O F X

2002-06-01

233

Simultaneous determination of alachlor, metolachlor, atrazine, and simazine in water and soil by isotope dilution gas chromatography/mass spectrometry  

SciTech Connect

A multiresidue method was developed for the simultaneous determination of low parts per billion (ppb) concentrations of the herbicides alachlor, metolachlor, atrazine, and simazine in water and soil using isotope dilution gas chromatography/mass spectrometry (GC/MS). Known amounts of /sup 15/N,/sup 13/C-alachlor and /sup 2/H/sub 5/-atrazine were added to each sample as internal standards. The samples were then prepared by a solid phase extraction with no further cleanup. A high resolution GC/low resolution MS system with data acquisition in selected ion monitoring mode was used to quantitate herbicides in the extract. The limit of detection was 0.05 ppb for water and 0.5 ppb for soil. Accuracy greater than 80% and precision better than 4% was demonstrated with spiked samples.

Huang, L.Q.

1989-03-01

234

Application of isotope dilution gas chromatography-mass spectrometry in analysis of organochlorine pesticide residues in ginseng root.  

PubMed

A highly accurate and precise method based on isotope dilution gas chromatography-mass spectrometry was developed for the determination of five matrix-bound organochlorine pesticides, namely, hexachlorobenzene and hexachlorocyclohexanes (alpha-, beta-, delta-, and gamma- isomers), in a reference sample of Panax gingseng. Identification of the analytes was confirmed under selective ion monitoring mode by the presence of two dominant ion fragments within the specific time windows (+/-1% of the relative retention time with respect to the calibration standards) and matching of relative ion intensities of the concerned ions in samples and calibration standards (within +/-5%). Quantification was based on the measurement of concentration ratios of the natural and isotopic analogues in the sample and calibration blends. To circumvent the tedious iterative process of exact isotope matching that is often used in isotope dilution mass spectrometry analysis, a single-point calibration procedure was adopted with the isotopic amount ratios in the sample and calibration blends close to unity (0.9-1.1). Under the described approach, intraday and interday repeatability of replicate analyses of organochlorine pesticides in the ginseng root sample were below 1.4%. The expanded relative uncertainty ranging from 4.0 to 6.5% at a coverage factor of 2 was significantly lower than those of conventional gas chromatographic methods using other calibration techniques (internal or external standards). A deviation of less than 2.0% from the certified values was achieved when applying the developed method to determine hexachlorobenzene, alpha-, and beta-hexachlorocyclohexane in a certified reference material (CRM), BCR-CRM 115. Because of the unavailability of relevant CRMs of herbal origins, the concerned ginseng root sample, after verification of the "true values" of the concerned organochlorine pesticides by the valid primary method, is suitable for serving as an in-house reference material for quality assurance and method validation purposes. PMID:17407316

Chan, Serena; Kong, Mei-Fong; Wong, Yiu-Chung; Wong, Siu-Kay; Sin, Della W M

2007-04-04

235

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

236

Dense-gas solvent-solute clusters at near-infinite dilution: EPR spectroscopic evidence  

SciTech Connect

The nitrogen hyperfine splitting constant of ditertbutyl nitroxide radicals was measured with electron paramagnetic resonance spectroscopy at near-infinite dilution in near-critical and supercritical ethane, as well as in liquid propane, liquid isobutane, and several nonhydrogen bonding liquid solvents. While the measurements in the liquids are described well by the theory of McRae, large deviations from the liquid behavior are observed in supercritical ethane. The deviations are used as a measure of the effective local density of the solvent around the solute. At the two temperatures investigated, T[sub r] = 1.009 and T[sub r] = 1.084, the local density enhancement, defined as the ratio of local to bulk densities, exhibits a maximum of about 3 occurring around 1/2 the critical density. The maximum is removed well from the critical density, where the maximum of the isothermal compressibility is observed. Local density enhancements are short-range effects and do not correlate well with the development of long-range critical phenomena. Local density enhancement data in ethane are compared with the prewetting transition that has been observed in near-critical ultrapure argon.

Carlier, C.; Randolph, T.W. (Yale Univ., New Haven, CT (United States))

1993-05-01

237

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

238

Competing Orders: Superfluidity and Spin Coherence in a Dilute Fermi Gas  

Microsoft Academic Search

The quest to achieve superfluidity in a two-component atomic Fermi gas is one of the most active research areas in ultra cold gases. Experimentally the possibility exists to prepare each atom in a superposition of two hyperfine states. In this case the system can be thought of as a spin-1\\/2 system, with longitudinal and transverse spin degrees of freedom. In

Jamie E. Williams; Nicolai N. Nygaard; Charles W. Clark

2003-01-01

239

Lung volumes in man immersed to the neck: dilution and plethysmographic techniques.  

PubMed

Previous studies of lung volumes during immersion have utilized dilution techniques for residual volume. We have compared lung volumes obtained by the use of a dual inert gas dilution technique with those determined by the Boyle's law technique in a plethysmograph designed to allow measurements in air and submersed to the neck in water. Both techniques gave similar results dry, but during immersion the dilution residual volume (RV) was 0.200 liter (16%) lower than the plethysmographic value (P greater than 0.001), which suggests that there is a significant amount of gas trapping during immersion due to breathing at low lung volumes and the central shift of blood. The unchanged RV due to hydrostatic force on the chest wall is balanced by the tendency to increase RV due to vascular congestion, which increases closing volume and stiffens the lung to compression. PMID:649469

Robertson, C H; Engle, C M; Bradley, M E

1978-05-01

240

An improved multiscale model for dilute turbulent gas particle flows based on the equilibration of energy concept  

SciTech Connect

Many particle-laden flows in engineering applications involve turbulent gas flows. Modeling multiphase turbulent flows is an important research topic with applications in fluidized beds and particle conveying. A predictive multiphase turbulence model can help CFD codes to be more useful for engineering applications, such as the scale-up in the design of circulating fluidized combustor and coal gasifications. In engineering applications, the particle volume fraction can vary from dilute (<10{sup -4}) to dense ({approx} 50%). It is reasonable to expect that multiphase turbulence models should at least satisfy some basic modeling and performance criteria and give reasonable predictions for the canonical problems in dilute particle-laden turbulent flows. In this research, a comparative assessment of predictions from Simonin and Ahmadi's turbulence models is performed with direct numerical simulation (DNS) for two canonical problems in particle-laden turbulent flows. Based on the comparative assessment, some criteria and the areas for model improvement are identified: (1) model for interphase TKE transfer, especially the time scale of interphase TKE transfer, and (2) correct prediction of TKE evolution with variation of particle Stokes number. Some deficiencies that are identified in the Simonin and Ahmadi models, limit the applicability. A new multiphase turbulence model, the Equilibration of Energy Model (EEM), is proposed in this work. In EEM, a multiscale interaction time scale is proposed to account for the interaction of a particle with a range of eddy sizes. EEM shows good agreement with the DNS results for particle-laden isotropic turbulence. For particle-laden homogeneous shear flows, model predictions from EEM can be further improved if the dissipation rate in fluid phase is modeled with more accuracy.

Xu, Ying

2005-05-01

241

The effect of positive end expiratory pressure on rebreathing and gas dilution in the Ayre's T-piece system--a laboratory study.  

PubMed

The effect of positive end expiratory pressure on the function of the Ayre's T-Piece System was studied using a simple lung model. Positive end expiratory pressure did not effect end tial CO2 during "controlled breathing" but caused an increase during "spontaneous breathing" when fresh gas flow was less than 3 times the minute volume. Gas dilution did not occur under any of the test conditions. PMID:352189

Dobbinson, T L; Fawcett, E R; Bolton, D P

1978-02-01

242

Kinetic Theory of Reactive Gas Mixtures with Application to Combustion  

Microsoft Academic Search

We consider a generalized Boltzmann equation valid for dilute, isotropic, polyatomic gas mixtures with chemical reactions. Depending on the ratio of characteristic times between reactive and inert collisions, various chemical regimes are obtained in the first order Enskog expansion and their compatibility with the Boltzmann H-theorem is investigated. We then review the mathematical structure of the transport linear systems resulting

A. Ern; V. Giovangigli

2003-01-01

243

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

244

Analysis of the surface heterogeneity of unmodified and modified silica by capillary inverse gas-solid chromatography at finite dilution  

SciTech Connect

The adsorption energy distributions (AEDs) of several molecular probes on two silica samples were determined from their chromatographic retention data. Adsorption data were obtained using the elution-by-characteristic points (ECP) method of capillary inverse gas chromatography at finite dilution. The diffuse rear profiles of the bands obtained with samples of different sizes overlay consistently. The numerical expectation-maximization (EM) method has been applied to the calculation of the AEDs from the unfitted experimental adsorption isotherms, using the Langmuir model for the local adsorption isotherm. Two silica samples, both unmodified and reacted with trimethylchlorosilane, were used. Results were obtained with methanol, diethyl ether, 1-chlorobutane, dichloromethane, and toluene. Their AEDs exhibit two high-energy peaks, around 45-60 and 50-70 kJ/mol, respectively. The differences observed for the specific capacities of adsorption and for the energy distributions of the unmodified and modified silicas are correlated with the chemical structure of the probe and the adsorbent surface. 17 refs., 10 figs., 4 tabs.

Pyda, M.; Stanley, B.J.; Xie, M.; Guiochon, G. (Univ. of Tennessee, Knoxville, TN (United States) Oak Ridge National Lab., TN (United States))

1994-05-01

245

INVESTIGATIONS OF THE POTASSIUM-ARGON METHOD OF AGE DETERMINATION USING SOLID ISOTOPIC DILUTION AND GAS REMOVAL BY CRUSHING  

Microsoft Academic Search

Preliminary work on a new technique of isotopic dilution analysis useful ; in the measurement of radiogenic Ar content of rocks or mineral samples in age ; determination is reported. Argon-38 is added to the sampies as the diluting ; isotope dissolved in a solid glassy silicate which approximates the pertinent ; properties of the sample. Crushing as well as

Naughton

1961-01-01

246

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

Microsoft Academic Search

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

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

1995-01-01

247

Simultaneous determination of amphetamine and methamphetamine enantiomers in urine by simultaneous liquidliquid extraction and diastereomeric derivatization followed by gas chromatographicisotope dilution mass spectrometry  

Microsoft Academic Search

A simple, rapid, reliable, and economic analytical scheme starting with in situ liquidliquid extraction and asymmetric (or diastereomeric) chemical derivatization (ChD) followed by gas chromatography (GC)-isotope dilution mass spectrometry (MS) is described for the simultaneous determination of d- and l-amphetamine (AP) and methamphetamine (MA) in urine which could have resulted from the administration of various forms of questioned amphetamines or

Sheng-Meng Wang; Ting-Cheng Wang; Yun-Seng Giang

2005-01-01

248

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

249

Vacuum versus sweeping gas operation for binary mixtures separation by dense membrane processes  

Microsoft Academic Search

When a gaseous phase takes place at the downstream side of a membrane separation process, two distinct options can be schematically operated in order to induce a driving force from that side: apply a lower pressure than the upstream one (thanks to a vacuum pump for instance), or exert a diluting effect by an inert gas sweep (under higher total

Ccile Vallieres; Eric Favre

2004-01-01

250

Aroma quality assessment of Korean fermented red pepper paste (gochujang) by aroma extract dilution analysis and headspace solid-phase microextraction-gas chromatography-olfactometry.  

PubMed

The objective of this study was to assess aroma quality of gochujang using purge and trap, simultaneous steam distillation and solvent extraction (SDE), and headspace solid-phase microextraction (HS-SPME), followed by gas chromatography-olfactometry (GC-O). Nineteen and 28 aroma-active compounds were detected by aroma extract dilution analysis of purge and trap and SDE, respectively. Diallyl disulfide and 3-isobutyl-2-methoxypyrazine played a significant role in the aroma quality of gochujang. Twelve aroma-active compounds were detected by HS-SPME-GC-O based on sample dilution analysis. Methional, diallyl disulfide, and 3-isobutyl-2-methoxypyrazine were the most intense aroma-active compounds. 3-Isobutyl-2-methoxypyrazine was identified for the first time in gochujang. PMID:24128505

Kang, Kyung-Mo; Baek, Hyung-Hee

2013-08-31

251

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

252

Quantitation of metabolites of the nerve agents sarin, soman, cyclohexylsarin, VX, and Russian VX in human urine using isotope-dilution gas chromatography-tandem mass spectrometry.  

PubMed

Organophosphorus nerve agents are among the most toxic organic compounds known and continue to be a threat for both military and terrorist use. We have developed an isotope-dilution gas chromatography-tandem mass spectrometric (GC-MS-MS) method for quantitating the urinary metabolites of the organophosphorus nerve agents sarin (GB), soman (GD), VX, Russian VX (RVX), and cyclohexylsarin (GF). Urine samples were acidified, extracted into ether-acetonitrile, derivatized by methylation with diazomethane, and analyzed by GC-MS-MS. The limits of detection were less than 1 micro g/L for all analytes. PMID:15239858

Barr, John R; Driskell, W J; Aston, Linda S; Martinez, Rodolfo A

253

Effect of isothermal dilution on emission factors of organic carbon and n-alkanes in the particle and gas phases of diesel exhaust  

NASA Astrophysics Data System (ADS)

To investigate the effect of isothermal dilution (30 C) on emission factors (EFs) of semivolatile and nonvolatile compounds of heavy-duty diesel exhaust, we measured EFs for particulate matter (PM), organic carbon (OC), and elemental carbon (EC) in the particle phase, and EFs for n-alkanes in both the particle phase and the gas phase of exhaust produced under high-idle engine operating conditions at dilution ratios (DRs) ranging from 8 to 1027. The EC EFs did not vary with DR, whereas the OC EFs in the particle phase determined at DR = 1027 were 13% of the EFs determined at DR = 8, owing to evaporation of organic compounds. Using partitioning theory and n-alkane EFs measured at DR = 14 and 238, we calculated the distributions of compounds between the particle and gas phases at DR = 1760, which corresponds to the DR for tailpipe emissions as they move from the tailpipe to the roadside atmosphere. The gas-phase EF of a compound with a vapor pressure of 10-7 Pa was 0.01 ?g kg-1-fuel at DR = 14, and this value is 1/330 the value derived at DR = 1760. Our results suggest that the EFs of high-volatility compounds in the particle phase will be overestimated and that the EFs of low-volatility compounds in the gas phase will be underestimated if the estimates are derived from data obtained at the low DRs and they are applied to the real world. Therefore, extrapolation from EFs derived at low DR values to EFs at atmospherically relevant DRs will be a source of error in predictions of the concentrations of particulate matter and gas-phase precursors to secondary organic aerosols in air quality models.

Fujitani, Yuji; Saitoh, Katsumi; Fushimi, Akihiro; Takahashi, Katsuyuki; Hasegawa, Shuich; Tanabe, Kiyoshi; Kobayashi, Shinji; Furuyama, Akiko; Hirano, Seishiro; Takami, Akinori

2012-11-01

254

Off-gas system development for the melt-dilute treatment of aluminum-based spent nuclear fuel  

Microsoft Academic Search

The Melt-Dilute treatment for aluminum-based spent nuclear fuel involves melting of the fuel to form a liquid solution of uranium-aluminum at a temperature of approximately 850 C. The containment and capture of the gaseous and volatile fission products potentially released at these temperatures is one of the key elements of the treatment process. Thermodynamic calculations have been performed to estimate

2000-01-01

255

Quantitative gas chromatography-olfactometry carried out at different dilutions of an extract. Key differences in the odor profiles of four high-quality Spanish aged red wines.  

PubMed

Four Spanish aged red wines made in different wine-making areas have been extracted, and the extracts and their 1:5, 1:50, and 1:500 dilutions have been analyzed by a gas chromatography-olfactometry (GC-O) approach in which three judges evaluated odor intensity on a four-point scale. Sixty-nine different odor regions were detected in the GC-O profiles of wines, 63 of which could be identified. GC-O data have been processed to calculate averaged flavor dilution factors (FD). Different ANOVA strategies have been further applied on FD and on intensity data to check for significant differences among wines and to assess the effects of dilution and the judge. Data show that FD and the average intensity of the odorants are strongly correlated (r(2) = 0.892). However, the measurement of intensity represents a quantitative advantage in terms of detecting differences. For some odorants, dilution exerts a critical role in the detection of differences. Significant differences among wines have been found in 30 of the 69 odorants detected in the experiment. Most of these differences are introduced by grape compounds such as methyl benzoate and terpenols, by compounds released by the wood, such as furfural, (Z)-whiskey lactone, Furaneol, 4-propylguaiacol, eugenol, 4-ethylphenol, 2,6-dimethoxyphenol, isoeugenol, and ethyl vanillate, by compounds formed by lactic acid bacteria, such as 2,3-butanedione and acetoine, or by compounds formed during the oxidative storage of wines, such as methional, sotolon, o-aminoacetophenone, and phenylacetic acid. The most important differences from a quantitative point of view are due to 2-methyl-3-mercaptofuran, 4-propylguaiacol, 2,6-dimethoxyphenol, and isoeugenol. PMID:11600028

Ferreira, V; Aznar, M; Lpez, R; Cacho, J

2001-10-01

256

Probing the effects of surfactant monolayers on gas- liquid collisions: Scattering studies of argon and xenon atoms striking dilute bismuth:gallium alloys  

NASA Astrophysics Data System (ADS)

Atomic beam scattering experiments are used to determine the ways in which surfactant Bi atoms alter energy transfer and scattering direction in collisions between Ar and Xe atoms and two dilute Bi:Ga alloys (0.02 and 0.2 atom% Bi in Ga). The Bi surface coverage of the dilute Bi:Ga solutions is measured with Auger Electron Spectroscopy (AES) and ranges from <1% at 673 K (0.02% Bi:Ga) to 98% at 313 K (0.2% Bi:Ga) of a Bi monolayer. The atomic beam scattering experiments show that surface Bi atoms reduce gas-liquid energy transfer between 92 kJ/mol Ar and 190 kJ/mol Xe atoms and the dilute alloys. The energy transfers take on pure Bi-like values at high Bi surface coverages, pure Ga-like values at low Bi surface coverages, and increase smoothly between the extremes of Bi-rich and Ga-rich surfaces. Surface Bi atoms are less effective at inhibiting Ar and Xe energy transfer when the incident energies of the gases are lowered (at incident energies of <30 kJ/mol for Ar and <75 kJ/mol for Xe). The effect of surface Bi atoms on the atomic-scale corrugation of the Bi, Ga, and Bi:Ga surfaces is investigated by measuring the Ar and Xe scattering intensity at ?inc = ? fin = 55 as a function of liquid temperature. The scattering intensities suggest that pure Ga presents a smoother liquid surface than either pure Bi or the low temperature (monolayer covered) alloy and that raising the temperature of the pure liquids increases surface roughness. The Ar and Xe intensities from the dilute Bi:Ga alloys suggest that the alloy surface is initially roughened as the temperature is increased but then becomes smoother at higher temperatures as surface Bi atoms are replaced with Ga atoms.

Morgan, Jason Aaron

257

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

258

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 gassolid 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

259

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

260

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

261

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

262

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

263

Dilution Confusion: Conventions for Defining a Dilution  

ERIC Educational Resources Information Center

|Two conventions for preparing dilutions are used in clinical laboratories. The first convention defines an "a:b" dilution as "a" volumes of solution A plus "b" volumes of solution B. The second convention defines an "a:b" dilution as "a" volumes of solution A diluted into a final volume of "b". Use of the incorrect dilution convention could

Fishel, Laurence A.

2010-01-01

264

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

265

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

PubMed

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

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

2013-06-20

266

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

NASA Astrophysics Data System (ADS)

Vibrational spectra of gas-source molecular beam epitaxy grown dilute InNxAs1-x/InP (001) alloys are obtained using a Fourier-transform infrared (IR) spectroscopy. A triply degenerate NAs local vibrational mode of Td-symmetry is observed near 438 cm-1 corresponding to the In-N bond energy. The analysis of composition dependent infrared reflectivity spectra in InNAs has predicted a two-phonon-mode behavior. In In(Ga)-rich GaInNAs alloys the observed splitting of the NAs local mode into a doublet for the NAs-Ga1(In1)In3(Ga3) pair-defect of C3v-symmetry is consistent with our simulated results based on a sophisticated Green's function theory.

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

2013-02-01

267

A rapid, sensitive method for the quantitation of specific metabolites of sulfur mustard in human urine using isotope-dilution gas chromatography-tandem mass spectrometry.  

PubMed

Sulfur mustard agent (HD) (2,2'-dichloroethyl sulfide), a Schedule I compound on the Chemical Weapons Convention Schedule of Chemicals, remains a public health concern because it is simple to synthesize and it is in the chemical weapon stockpiles of several countries. A sensitive, rapid, accurate, and precise method was developed to quantitate trace levels of 1,1'-sulfonylbis [2-(methylthio) ethane] (SBMTE) in human urine as a means of assessing exposure to HD. The method used immobilized liquid-liquid extraction with diatomaceous earth, followed by the analysis of the urine extract using isotope-dilution gas chromatography-tandem mass spectrometry. Relative standard deviations were less than 8.6% at 1 ng/mL and 3.6% at 20 ng/mL. The limit of detection for SBMTE was 0.038 ng/mL in 0.5 mL of urine. PMID:15239853

Young, Carrie L; Ash, Doris; Driskell, W J; Boyer, Anne E; Martinez, Rodolfo A; Silks, L A; Barr, John R

268

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

PubMed

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

Wang, Jian-Hua; Guo, Cui

2010-07-01

269

The growth of bunched and multi-circularly wrapped carbon nanotubes on bulk magnetic alloys by microwave enhanced hot-filament CVD with a dilute gas of ammonia  

NASA Astrophysics Data System (ADS)

Bunched and multi-circularly wrapped carbon nanotubes (CNT) are observed to grow on alloy substrates based on iron group metals and copper by a microwave enhanced hot-filament method with a dilute gas of ammonia at a proper RF self-bias. The grown size of CNTs embodied in the grain sizes of conducting bulk alloy catalysts such as Cu-Ni, Cu-Fe, Cu-Co, and Cu-Ni-Fe-Co are controlled by a precursor time of hydrogen plasma etching. Species with different structural features and homogenization of CNTs samples are produced crucially attributed to various reactant gases and self-bias induced by the radio frequency field.

Miao, H. Y.; Lue, J. T.; Chen, S. K.; Tsau, C. H.; Ouyang, M. S.

2005-02-01

270

Determination of atrazine, lindane, pentachlorophenol, and diazinon in water and soil by isotope dilution gas chromatography/mass spectrometry  

SciTech Connect

This paper describes an isotope dilution GC/MS technique for the analysis of low-parts-per-billion concentrations of atrazine, lindane, pentachlorophenol, and diazinon in water and soil. Known amounts of stable-labeled isotopes such as atrazine-d/sub 5/, lindane-d/sub 6/, pentachlorophenol-/sup 13/C/sub 6/, and diazinon-d/sub 10/ are spiked into each sample prior to extraction. Water samples are extracted with methylene chloride; soil samples are extracted with acetone/hexane. Analysis is performed by high-resolution GC/MS with the mass spectrometer operated in the selected ion monitoring mode. Accuracy greater than 86% and precision better than 8% were demonstrated by use of spiked samples. This technique has been used successfully in the analysis of over 300 water and 300 soil samples. Detection limits of 0.1-1.0 ppb were achieved for the test compounds by selected ion monitoring GC/MS. 8 references, 2 figures, 4 tables.

Lopez-Avila, V.; Hirata, P.; Kraska, S.; Flanagan, M.; Taylor, J.H. Jr.; Hern, S.C.

1985-12-01

271

Binary CF 3Br- and CHF 3inert 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

272

Airborne measurements of sulfur dioxide, dimethyl sulfide, carbon disulfide, and carbonyl sulfide by isotope dilution gas chromatography\\/mass spectrometry  

Microsoft Academic Search

A gas chromatograph\\/mass spectrometer is described for determining atmospheric sulfur dioxide, carbon disulfide, dimethyl sulfide, and carbonyl sulfide from aircraft and ship platforms. Isotopically labelled variants of each analyte were used as internal standards to achieve high precision. The lower limit of detection for each species for an integration time of 3 min was 1 pptv for sulfur dioxide and

Alan R. Bandy; Donald C. Thornton; Arthur R. Driedger

1993-01-01

273

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

274

Development and validation of a new analytical method for the determination of 1,4-dichlorobenzene in honey by gas chromatographyisotope dilution mass spectrometry after steam-distillation  

Microsoft Academic Search

A simple, fast, sensitive and robust analytical method using gas chromatography (GC)isotope dilution mass spectrometry (MS) was developed and validated for the identification and quantification of 1,4-dichlorobenzene (p-DCB) residues in honey samples. The proposed methodology is based on steam-distillation using a Clevenger-type apparatus followed by gas chromatographymass spectrometry (GCMS) in the selected ion monitoring (SIM) mode employing the isotopically labeled

E. V. Botitsi; P. N. Kormali; S. N. Kontou; A. Economou; D. F. Tsipi

2006-01-01

275

Airborne measurements of sulfur dioxide, dimethyl sulfide, carbon disulfide, and carbonyl sulfide by isotope dilution gas chromatography/mass spectrometry  

SciTech Connect

A gas chromatograph/mass spectrometer is described for determining atmospheric sulfur dioxide, carbon disulfide, dimethyl sulfide, and carbonyl sulfide from aircraft and ship platforms. Isotopically labelled variants of each analyte were used as internal standards to achieve high precision. The lower limit of detection for each species for an integration time of 3 min was 1 pptv for sulfur dioxide and dimethyl sulfide and 0.2 pptv for carbon disulfide and carbonyl sulfide. All four species were simultaneously determined with a sample frequency of one sample per 6 min or greater. When only one or two species were determined, a frequency of one sample per 4 min was achieved. Because a calibration is included in each sample, no separate calibration sequence was needed. Instrument warmup was only a few minutes. The instrument was very robust in field deployments, requiring little maintenance.

Bandy, A.R.; Thornton, D.C.; Driedger, A.R. III [Drexel Univ., Philadelphia, PA (United States)

1993-12-01

276

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

277

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

278

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

PubMed

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

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

2009-04-01

279

Isotope dilution high-resolution gas chromatography/high-resolution mass spectrometry method for analysis of selected acidic herbicides in surface water.  

PubMed

In this work, an isotope dilution method for determination of selected acidic herbicides by high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS) was developed for surface water samples. Average percent recoveries of native analytes were observed to be between 70.8 and 93.5% and average recoveries of labeled quantification standards [(13)C(6)]2,4-D and [(13)C(6)]2,4,5-T were 85.5 and 101%, respectively. Using this method, detection limits of 0.05 ng/L for dicamba, MCPA, MCPP, and triclopyr, and 0.5 ng/L for 2,4-D were routinely achieved. The method was applied to measuring the concentration of these analytes in surface water samples collected from five sampling locations in the Lower Fraser Valley region of British Columbia, Canada. All of the herbicides monitored were detected at varying levels in the surface water samples collected. The highest concentrations detected for each analyte were 345 ng/L for 2,4-D, 317 ng/L for MCPA, 271 ng/L for MCPP, 15.7 ng/L for dicamba, and 2.18 ng/L for triclopyr. Average detection frequencies of the herbicides were 95% for MCPA, 80% for MCPP, 70% for dicamba, 65% for 2,4-D, and 46% for triclopyr. Seasonal variations of herbicide levels are also discussed. PMID:16956613

Woudneh, Million B; Sekela, Mark; Tuominen, Taina; Gledhill, Melissa

2006-09-07

280

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

281

Application of the carbon dioxide-barium hydroxide hydrate gas-solid reaction for the treatment of dilute carbon dioxide-bearing gas streams  

SciTech Connect

The removal of trace components from gas streams via irreversible gas-solid reactions in an area of interest to the chemical engineering profession. This research effort addresses the use of fixed beds of Ba(OH)/sub 2/ hydrate flakes for the removal of an acid gas, CO/sub 2/, from air that contains approx. 330 ppM/sub v/ CO/sub 2/. Areas of investigation encompassed: (1) an extensive literature review of Ba(OH)/sub 2/ hydrate chemistry, (2) microscale studies on 0.150-g samples to develop a better understanding of the reaction, (3) process studies at the macroscale level with 10.2-cm-ID fixed-bed reactors, and (4) the development of a model for predicting fixed-bed performance. Experimental studies indicated fixed beds of commercial Ba(OH)/sub 2/.8H/sub 2/O flakes at ambient temperatures to be capable of high CO/sub 2/-removal efficiencies (effluent concentrations <100 ppB), high reactant utilization (>99%), and an acceptable pressure drop (1.8 kPa/m at a superficial gas velocity of 13 cm/s). Ba(OH)/sub 2/.8H/sub 2/O was determined to be more reactive toward CO/sub 2/ than either Ba(OH)/sub 2/.3H/sub 2/O or Ba(OH)/sub 2/.1H/sub 2/O. A key variable in the development of this fixed-bed process was relative humidity. Operation at conditions with effluent relative humidities >60% resulted in significant recrystallization and restructuring of the flake and subsequent pressure-drop problems.

Haag, G.L.

1983-09-01

282

Modeling the effects of size on patch dynamics of an inert tracer  

NASA Astrophysics Data System (ADS)

Mesoscale iron enrichment experiments have revealed that additional iron affects the phytoplankton productivity and carbon cycle. However, the role of initial size of fertilized patch in determining the patch evolution is poorly quantified due to the limited observational capability and complex of physical processes. Using a three-dimensional ocean circulation model, we simulated different sizes of inert tracer patches that were only regulated by physical circulation and diffusion. Model results showed that during the first few days since release of inert tracer, the calculated dilution rate was found to be a linear function with time, which was sensitive to the initial patch size with steeper slope for smaller size patch. After the initial phase of rapid decay, the relationship between dilution rate and time became an exponential function, which was also size dependent. Therefore, larger initial size patches can usually last longer and ultimately affect biogeochemical processes much stronger than smaller patches.

Xiu, P.; Chai, F.

2010-03-01

283

Modeling the effects of size on patch dynamics of an inert tracer  

NASA Astrophysics Data System (ADS)

Mesoscale iron enrichment experiments have revealed that additional iron affects the phytoplankton productivity and carbon cycle. However, the role of initial size of fertilized patch in determining the patch evolution is poorly quantified due to the limited time of research vessels at sea. Using a three-dimensional ocean circulation model, we simulated different sizes of inert tracer patches that were only regulated by physical circulation and diffusion. Model results showed that during the first few days since release of inert tracer, the calculated dilution rate was found to be a linear function with time, which was sensitive to the initial patch size with steeper slope for smaller size patch. After the initial phase of rapid decay, the relationship between dilution rate and time became an exponential function, which was also size dependent. Therefore, larger initial size patches can usually last longer and ultimately affect biogeochemical processes much stronger than smaller patches.

Xiu, P.; Chai, F.

2009-08-01

284

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

285

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

286

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

287

Simultaneous determination of amphetamine and methamphetamine enantiomers in urine by simultaneous liquid-liquid extraction and diastereomeric derivatization followed by gas chromatographic-isotope dilution mass spectrometry.  

PubMed

A simple, rapid, reliable, and economic analytical scheme starting with in situ liquid-liquid extraction and asymmetric (or diastereomeric) chemical derivatization (ChD) followed by gas chromatography (GC)-isotope dilution mass spectrometry (MS) is described for the simultaneous determination of D- and L-amphetamine (AP) and methamphetamine (MA) in urine which could have resulted from the administration of various forms of questioned amphetamines or amphetamines-generating drugs. By using L-N-trifluoroacetyl-1-prolyl chloride (L-TPC) as chiral derivatizing agent, resolutions of 2.2 and 2.0 were achieved for the separation of AP and MA enantiomeric pairs, respectively, on an ordinary HP-5MS capillary column. The GC-MS quantitation was carried out in the selected ion monitoring (SIM) mode using m/z 237 and 251 as the quantifier ions for the respective diastereomeric pairs of AP-L-TPC and MA-L-TPC. The calibration curves plotted for the two pairs of analytes stretch with good linearity down to 45 ng/mL, and the limits of detection and quantitation determined were as low as 40 and 45 ng/mL, respectively. Also, a comparative study using 10 real-case urine specimens previously screened as positive for MA administration showed mostly tolerable biases between the two sums (of concentration) of D- and L-MA obtained via an asymmetric L-TPC-ChD approach and via an ordinary pentafluoropropionylation (PFPA-ChD) approach, respectively, as well as between the two sums of D- and L-AP obtained thereupon, thus validating the proposed analytical scheme as a promising forensic protocol for the detailed analysis of enantiomeric amphetamines in urine. PMID:15664343

Wang, Sheng-Meng; Wang, Ting-Cheng; Giang, Yun-Seng

2005-02-25

288

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

289

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

290

Gasliquid chromatography measurements of activity coefficients at infinite dilution of various organic solutes and water in tri- iso-butylmethylphosphonium tosylate ionic liquid  

Microsoft Academic Search

Activity coefficients at infinite dilution (?13?) of 33 different solutes (including alkanes, cycloalkanes, alkenes, alkynes, benzene, alkylbenzenes, water, alcohols, MTBE, thiophene and THF) in the ionic liquid tri-iso-butylmethylphosphonium tosylate have been determined by using the GLC method and have been reported over the temperature range (298.15 to 368.15)K. The partial molar excess enthalpies of mixing at infinite dilution have been

Urszula Doma?ska; Kamil Paduszy?ski

2010-01-01

291

Dilutions Made Easy.  

ERIC Educational Resources Information Center

Presents problems appropriate for high school and college students that highlight dilution methods. Promotes an understanding of dilution methods in order to prevent the unnecessary waste of chemicals and glassware in biology laboratories. (JRH)

Kamin, Lawrence

1996-01-01

292

Serial Dilution Simulation Lab  

ERIC Educational Resources Information Center

|Serial dilution is often a difficult concept for students to understand. In this short dry lab exercise, students perform serial dilutions using seed beads. This exercise helps students gain skill at performing dilutions without using reagents, bacterial cultures, or viral cultures, while being able to visualize the process.|

Keler, Cynthia; Balutis, Tabitha; Bergen, Kim; Laudenslager, Bryanna; Rubino, Deanna

2010-01-01

293

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

294

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. Vasileva; E. A. Dyakonova; A. V. Erofeev; A. D. Zuev; T. A. Lapushkina; A. A. Markhotok

1997-01-01

295

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

296

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

297

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

298

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

299

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

300

Stable-isotope dilution gas chromatographymass spectrometric measurement of 3-hydroxyglutaric acid, glutaric acid and related metabolites in body fluids of patients with glutaric aciduria type 1 found in newborn screening  

Microsoft Academic Search

We developed a simple and sensitive stable-isotope dilution method for the quantification of 3-hydroxyglutaric acid (3HGA) and glutaric acid (GA) in body fluids. In our method, tert-butyldimethylsilyl (tBDMS) derivatives of 3HGA and GA were measured with a conventional electron-impact ionization (EI) mode in gas chromatographymass spectrometry (GCMS). The control values for 3HGA in nmol\\/ml were 0.150.08 (serum; n=10) and 0.070.03

Yosuke Shigematsu; Ikue Hata; Yukie Tanaka; Go Tajima; Nobuo Sakura; Etsuo Naito; Toru Yorifuji

2005-01-01

301

Generation and induced emission on transitions in Xe2Cl* exciplex molecules in Xe-CCl4 and Ar-Xe-CCl4 "Dilute" gas mixtures pumped by pulsed electron beam  

NASA Astrophysics Data System (ADS)

We have experimentally studied spontaneous and induced emission from Xe2Cl* triplex molecules in Xe-CCl4 and Ar-Xe-CCl4 "dilute" gas mixtures excited by a pulsed high-energy electron beam. For an energy of about 0.004 J/pulse deposited in a 4-cm-long cavity, a regime of spontaneous emission amplification in a wavelength range of 430-550 nm is realized on transitions from 22B2 and 42? states of Xe2Cl* molecules.

Mis'kevich, A. I.; Guo, Jinbo

2013-04-01

302

Dilute Suspensions near Walls  

NASA Astrophysics Data System (ADS)

A precise account of particle-wall hydrodynamic interactions is important for modelling the motion of dilute suspensions near walls. Particles considered here are solid, spherical and small enough for the Reynolds number of the flow around each particle to be small compared with unity. At first order in Reynolds number, Stokes equations apply. Ambient flow fields are expressed as polynomials in terms of the coordinates. Various flow fields perturbed by a spherical particle near a wall may be superimposed by linearity of Stokes equations. Their solutions are recalled; they were calculated with the bispherical coordinates technique, providing precise results for the drag and torque on a particle. For particles in a gas, particle inertia may be important even though for low Reynolds number fluid inertia is negligible. It is shown that collision of a particle on a wall is not possible in creeping flow even if particle inertia is not negligible. At second order in the low Reynolds number, a small fluid inertia appears. For a sphere moving in a linear shear flow and a quadratic shear flow along a wall, there is then a lift force. The various pair couplings between sphere translation, rotation and the shear flows provide contributions to the lift. For a particle moving normal to a wall in a quiescent fluid at constant velocity, fluid inertia provides steady and unsteady contributions to the drag force.

Feuillebois, F.; Yahiaoui, S.

2008-10-01

303

Light-soaking in aSiC:H films grown by PECVD in undiluted and hydrogen diluted SiH 4 + CH 4 gas mixtures  

Microsoft Academic Search

Amorphous silicon carbon alloys having an energy gap in the range 2.02.5 eV were deposited by plasma enhanced chemical vapor deposition (PECVD) from undiluted and hydrogen diluted SiH4 + CH4 mixtures. The optoelectronic and compositional properties of the samples were measured. Light soaking till saturation was performed on the samples and the effect on defect densities and photoconduction was investigated

M. Fathallah; R. Gharbi; G. Crovini; F. Demichelis; F. Giorgis; C. F. Pirri; E. Tresso; P. Rava

1996-01-01

304

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

305

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

306

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

307

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

308

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

309

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

310

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

311

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 1.62.0mm in diameter), and a commercial

Heidi Bernas; Kari Ernen; Irina Simakova; Anne-Riikka Leino; Krisztin Kords; Jukka Myllyoja; Pivi Mki-Arvela; Tapio Salmi; Dmitry Yu. Murzin

2010-01-01

312

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

313

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

314

Probing the center-vortex area law in d=3: The role of inert vortices  

NASA Astrophysics Data System (ADS)

In center-vortex theory, beyond the simplest picture of confinement several conceptual problems arise that are the subject of this paper. Recall that confinement arises through configuration averaging of phase factors associated with the gauge center group, raised to powers depending on the total Gauss link number of a vortex ensemble with a given Wilson loop. The simplest approach to confinement counts this link number by counting the number of vortices, considered in d=3 as infinitely long closed self-avoiding random walks of fixed step length, piercing any surface spanning the Wilson loop. Problems arise because a given vortex may pierce a given spanning surface several times without being linked or without contributing a nontrivial phase factor, or it may contribute a nontrivial phase factor appropriate to a smaller number of pierce points. We estimate the dilution factor ?, due to these inert or partially inert vortices, that reduces the ratio of fundamental string tension KF to the areal density ? of vortices from the ratio given by elementary approaches and find ?=0.60.1. Then we show how inert vortices resolve the problem that the link number of a given vortex-Wilson-loop configuration is the same for any spanning surface of whatever area, yet a unique area (of a minimal surface) appears in the area law. Third, we discuss semiquantitatively a configuration of two distinct Wilson loops separated by a variable distance, and show how inert vortices govern the transition between two possible forms of the area law (one at small loop separation, the other at large), and point out the different behaviors in SU(2) and higher groups, notably SU(3). The result is a finite-range van der Waals force between the two loops. Finally, in a problem related to the double-loop problem, we argue that the analogs of inert vortices do not affect the fact that, in the SU(3) baryonic area law, the mesonic string tension appears.

Cornwall, John M.

2006-03-01

315

THE EFFECT OF PARTICLE DILUTION ON WETTING EFFICIENCY AND LIQUID FILM THICKNESS IN SMALL TRICKLE BEDS  

Microsoft Academic Search

Partial wetting in small scale trickle bed reactors results in incorrect determination of intra-particle apparent kinetic parameters as well as in erroneous reactor scale-up. Although a dilution of catalyst particles with inert fines improves the catalyst wetting efficiency, it does not guarantee full external catalyst wetting at all superficial liquid mass velocities. In this work, a method is presented to

D. TSAMATSOULIS; M. H. AL-DAHHAN; F. LARACHI; N. PAPAYA NNAKOS

2001-01-01

316

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

317

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

318

CFD simulation of dilute phase gassolid riser reactors: part IIsimultaneous adsorption of SO 2NO x from flue gases  

Microsoft Academic Search

Simultaneous adsorption of SO2NOx in a riser configuration is a novel route for flue gas cleaning. The riser operates at a low flux (2kgm?2s?1) of small diameter (dp=60?m) Na-?-Al2O3 sorbent particles. The reaction scheme is adopted from previous work (Ind. Eng. Chem. Res. 40 (2001) 119), without adjusting any of the kinetic parameters. The significant concentration gradient between the gas

A. K. Das; J. De Wilde; G. J. Heynderickx; G. B. Marin

2004-01-01

319

Evaluation of oxygen pressurized microwave-assisted digestion of botanical materials using diluted nitric acid.  

PubMed

The feasibility of diluted nitric acid solutions for microwave-assisted decomposition of botanical samples in closed vessels was evaluated. Oxygen pressurized atmosphere was used to improve the digestion efficiency and Al, Ca, K, Fe, Mg and Na were determined in digests by inductively coupled plasma optical emission spectrometry (ICP OES). Efficiency of digestion was evaluated taking into account the residual carbon content (RCC) and residual acidity in digests. Samples were digested using nitric acid solutions (2, 3, 7, and 14 mol L(-1) HNO(3)) and the effect of gas phase composition inside the reaction vessels by purging the vessel with Ar (inert atmosphere, 1 bar), air (20% of oxygen, 1 bar) and pure O(2) (100% of oxygen, 1 bar) was evaluated. The influence of oxygen pressure was studied using pressures of 5, 10, 15 and 20 bar. It was demonstrated that a diluted nitric acid solution as low as 3 mol L(-1) was suitable for an efficient digestion of sample masses up to 500 mg of botanical samples using 5 bar of oxygen pressure. The residual acidities in final digests were lower than 45% in relation to the initial amount of acid used for digestion (equivalent to 1.3 mol L(-1) HNO(3)). The accuracy of the proposed procedure was evaluated using certified reference materials of olive leaves, apple leaves, peach leaves and pine needles. Using the optimized conditions for sample digestion, the results obtained were in agreement with certified values. The limit of quantification was improved up to a factor of 14.5 times for the analytes evaluated. In addition, the proposed procedure was in agreement with the recommendations of the green chemistry once it was possible to obtain relatively high digestion efficiency (RCC<5%) using only diluted HNO(3), which is important to minimize the generation of laboratory residues. PMID:21238716

Bizzi, Cezar Augusto; Barin, Juliano Smanioto; Mller, Edson Irineu; Schmidt, Lucas; Nbrega, Joaquim A; Flores, Erico Marlon Moraes

2010-11-17

320

Stable Isotope Dilution for Hazardous Waste Incineration.  

National Technical Information Service (NTIS)

The report gives results of a project to determine if a proposed catalytic exchange procedure could be adapted to produce the labeled analog materials necessary for isotope dilution gas chromatography/mass spectrometry (GC/MS) analysis. It is related to a...

P. W. Ryan

1984-01-01

321

Dilution in single pass arc welds  

Microsoft Academic Search

A study was conducted on dilution of single pass arc welds of type 308 stainless steel filler metal deposited onto A36 carbon\\u000a steel by the plasma arc welding (PAW), gas tungsten arc welding (GTAW), gas metal arc welding (GMAW), and submerged are welding\\u000a (SAW) processes. Knowledge of the arc and melting efficiency was used in a simple energy balance to

J. N. DuPont; A. R. Marder

1996-01-01

322

Extinction of diffusion flames burning diluted methane and diluted propane in diluted air  

SciTech Connect

A theoretical and experimental investigation of the extinction limits of counterflow diffusion flames burning methane and propane is outlined. A diffusion flame is stabilized between counterflowing streams of a fuel diluted with nitrogen and air diluted with nitrogen. Extinction limits for such flames were measured over a wide parametric range. Results for methane and propane were found to be in appropriate agreement with previous measurements. The experimental results are interpreted by use of activation energy asymptotic theories developed previously. The gas-phase chemical reaction is approximated as a one step, irreversible process with a large value for the ratio of the activation energy characterizing the chemical reaction to the thermal energy in the flame. Equilibrium dissociation of products is neglected. The theoretical predictions are compared with experimental results, and the overall chemical kinetic rate parameters characterizing the gas-phase oxidation of methane and propane in a diffusion flame are deduced. The overall chemical kinetic rate parameters deduced by use of this procedure are valid only at flame temperatures where equilibrium dissociation is negligible. The scalar dissipation rate at extinction is predicted over a wide range.

Puri, I.K.; Seshadri, K.

1986-08-01

323

Design of a Compact Dilution Sampler for Stationary Combustion Sources  

Microsoft Academic Search

The dilution sampling method simulates the rapid cooling and dilution processes after hot flue gas have left the stack. This allows gases or vapors to nucleate both homogeneously and heterogeneously, and to condense on preexisting particles in processes analogous to those that occur in the ambient environment. Using this method the authors can collect filterable particulate matter (PM) and condensible

Xinghua Li; Shuxiao Wang; Lei Duan; Jiming Hao; Zhengwei Long

2011-01-01

324

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

325

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

326

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

327

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

NASA Astrophysics Data System (ADS)

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

Cornell, Eric A.

1997-04-01

328

Approach to the thermodynamics of enantionmer separation by gas chromatography Enantioselectivity between the chiral inhalation anesthetics enflurane, isoflurane and desflurane and a diluted ?-cyclodextrin derivative  

Microsoft Academic Search

The thermodynamics of enantioselectivity, ??D,L(?G), ??D,L(?H), ?D,L(?S) and Tiso, have been determined by gas chromatography employing the concept of the retention increment R? for the inhalation anesthetics enflurane (1), isoflurane (2) and desflurane (3) and the selector octakis(3-O-butanoyl-2,6-di-O-n-pentyl)-?-cyclodextrin (4) in the polysiloxane SE-54. It is shown that the separation factor ? is concentration dependent. Therefore, the separation factor ? should

V. Schurig; M. Juza

1997-01-01

329

Pitfalls encountered during quantitative determination of 3-alkyl-2-methoxypyrazines in grape must and wine using gas chromatography-mass spectrometry with stable isotope dilution analysis. Comprehensive two-dimensional gas chromatography-mass spectrometry and on-line liquid chromatography-multidimensional gas chromatography-mass spectrometry as potential loopholes.  

PubMed

The analysis of 3-alkyl-2-methoxypyrazines in Vitis vinifera grape must or wine at the low nanogram per liter level failed in several situations when applying a one-dimensional gas chromatographic analysis with mass spectrometric detection (GC-MS). Sample preparation methods such as headspace solid phase microextraction or solid phase extraction were convenient procedures, however lacking extraction selectivity for complex matrices. Analysis by comprehensive two-dimensional gas chromatography with mass spectrometric detection clearly demonstrated the potential for co-elution in such matrices and the risk for erroneous results when applying one-dimensional GC-MS. In one example, matrix problems would have been a challenge even for a comprehensive two-dimensional chromatographic approach with MS detection (GCGC-MS). A solution to matrix problems was found by protonating the 3-alkyl-2-methoxypyrazines in acidic pH and sample clean-up using solid phase extraction with a mixed-mode polymeric cation-exchange sorbent. Quantification was performed by a stable isotope dilution assay, following analysis by on-line coupled high performance liquid chromatography with multidimensional gas chromatography and detection with mass spectrometry (on-line LC-MDGC-MS). This new approach allowed trace-level analysis of 3-alkyl-2-methoxypyrazines in grape musts and wines and is described for V. vinifera Sauvignon blanc, following 3-alkyl-2-methoxypyrazines concentrations during ripening and in the processed wines. PMID:20637469

Schmarr, Hans-Georg; Ganss, Sebastian; Koschinski, Stefan; Fischer, Ulrich; Riehle, Carmen; Kinnart, Julian; Potouridis, Theodoros; Kutyrev, Maria

2010-06-25

330

Dilution pole combustor and method  

SciTech Connect

A gas turbine engine annular combustor having a longitudinal centerline axis, outer and inner annular liners is described spaced radially apart coaxially about the centerline axis to define an annular combustion chamber there between, an annular dome at upstream ends of the liners having a plurality of circumferentially spaced apart carburetors for providing a fuel/air mixture into the combustion chamber to generate combustion gases therein, and an annular outlet defined at downstream ends of the liners for discharging the combustion gases, a method comprising: channeling the fuel/air mixture axially through the dome into the combustion chamber to generate the combustion gases; blocking flow of the combustion gases at a plurality of circumferentially spaced apart locations at an axial position spaced axially downstream from the dome and spaced axially upstream from the outlet to define an intermediate zone disposed axially between a forward zone extending upstream therefrom to the dome, and an aft zone extending downstream therefrom to the outlet, and radially between the outer and inner liners to accelerate the combustion gases between the blocking locations in a plurality of circumferentially spaced apart throats; injecting dilution air into the combustion gases being channeled through the throats and radially between the outer and inner liners channeling the combustion gases through the forward zone with a rich equivalence ratio; and wherein the injecting step mixes the dilution air with the combustion gases being channeled through the throats to quench the combustion gases channeled to the aft zone to a lean equivalence ratio.

Stickles, R.W.; Dodds, W.J.; Sabla, P.E.; Cook, G.E.; Loconti, C.L.; MacHolloway, G.

1993-08-31

331

Development and validation of a new analytical method for the determination of 1,4-dichlorobenzene in honey by gas chromatography-isotope dilution mass spectrometry after steam-distillation.  

PubMed

A simple, fast, sensitive and robust analytical method using gas chromatography (GC)-isotope dilution mass spectrometry (MS) was developed and validated for the identification and quantification of 1,4-dichlorobenzene (p-DCB) residues in honey samples. The proposed methodology is based on steam-distillation using a Clevenger-type apparatus followed by gas chromatography-mass spectrometry (GC-MS) in the selected ion monitoring (SIM) mode employing the isotopically labeled analogue d4-1,4-dichlorobenzene (d4-p-DCB) as internal standard (IS). Validation of the method was performed in two different GC-MS systems, using quadrupole MS (QMS) and ion-trap MS (ITMS) detectors, with no statistically significant differences between two. Recoveries were better than 91% with percent relative standard deviations lower than 12%. The instrumental limits of detection were 1 microg kg(-1) in the GC-ITMS system and 0.6 microg kg(-1) in the GC-QMS system. The expanded uncertainty was estimated as 17% at the currently accepted "action level" of 10 microg kg(-1). The method was applied to the analysis of 310 honey samples in an extensive national monitoring study. A quality control (QC) system applied during the assays has demonstrated a good performance and long-term stability over a period of more than 8 months of continuous operation. PMID:17723727

Botitsi, E V; Kormali, P N; Kontou, S N; Economou, A; Tsipi, D F

2006-07-14

332

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

333

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

334

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

335

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

336

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

337

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

338

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

339

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

340

Dilution assay statistics.  

PubMed Central

A parametric method of statistical analysis for dilution assays is developed in detail from first principles of probability and statistics. The method is based on a simple product binomial model for the experiment and produces an estimate for the concentration of target entities, a confidence interval for this concentration, and an indicator of the quality of the assay called the p value for goodness of fit. The procedure is illustrated with data from a virologic quantitative micrococulture assay used to quantify free human immunodeficiency virus in clinical trials. The merits of the procedure versus those of nonparametric methods of estimating the dilution inducing a 50% response rate are discussed. Advantages of the proposed approach include plausibility of the underlying assumptions, ability to assess plausibility of specific experimental outcomes through their likelihood, and plausibility of confidence intervals.

Myers, L E; McQuay, L J; Hollinger, F B

1994-01-01

341

Probing the center-vortex area law in d=3: The role of inert vortices  

SciTech Connect

In center-vortex theory, beyond the simplest picture of confinement several conceptual problems arise that are the subject of this paper. Recall that confinement arises through configuration averaging of phase factors associated with the gauge center group, raised to powers depending on the total Gauss link number of a vortex ensemble with a given Wilson loop. The simplest approach to confinement counts this link number by counting the number of vortices, considered in d=3 as infinitely long closed self-avoiding random walks of fixed step length, piercing any surface spanning the Wilson loop. Problems arise because a given vortex may pierce a given spanning surface several times without being linked or without contributing a nontrivial phase factor, or it may contribute a nontrivial phase factor appropriate to a smaller number of pierce points. We estimate the dilution factor {alpha}, due to these inert or partially inert vortices, that reduces the ratio of fundamental string tension K{sub F} to the areal density {rho} of vortices from the ratio given by elementary approaches and find {alpha}=0.6{+-}0.1. Then we show how inert vortices resolve the problem that the link number of a given vortex-Wilson-loop configuration is the same for any spanning surface of whatever area, yet a unique area (of a minimal surface) appears in the area law. Third, we discuss semiquantitatively a configuration of two distinct Wilson loops separated by a variable distance, and show how inert vortices govern the transition between two possible forms of the area law (one at small loop separation, the other at large), and point out the different behaviors in SU(2) and higher groups, notably SU(3). The result is a finite-range van der Waals force between the two loops. Finally, in a problem related to the double-loop problem, we argue that the analogs of inert vortices do not affect the fact that, in the SU(3) baryonic area law, the mesonic string tension appears.

Cornwall, John M. [Department of Physics and Astronomy, University of California, Los Angeles, California 90095 (United States)

2006-03-15

342

Analysis of organochlorines in harbor seal (Phoca vitulina) tissue samples from Alaska using gas chromatography/ion trap mass spectrometry by an isotopic dilution technique.  

PubMed

A gas chromatography/ion trap mass spectrometry (GC/ITMS) method was developed for the determination of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polychlorinated naphthalenes (PCNs) in harbor seal (Phoca vitulina) tissues. Tissue samples were homogenized, lyophilized and fortified with (13)C-PCBs 28, 123, 169 and 170, and then extracted with an accelerated solvent extractor with a mixture of hexane and methylene chloride (1:1, v/v). After lipid removal using a 40% H(2)SO(4)-modified silica gel column, all organochlorines were collected in one fraction and further fractionated with an activated carbon/silica gel (1:20) column into a first fraction containing OCPs, non-coplanar PCBs and (13)C-PCBs 28, 123 and 170, and a second containing PCNs, coplanar PCBs and (13)C-PCB 169. Prior to GC/MS/MS analysis, (13)C-PCB 169 was added into the first fraction as an injection standard and (13)C-PCB 170 into the second fraction to calibrate the recoveries of the fortified internal standards. This method can effectively eliminate matrix interferences, and has high selectivity and sensitivity. Recoveries averaged 45-86% for OCPs with relative standard deviations (RSDs) of 2-14%, 52-137% for PCBs with RSDs of 3-29% and 36-152% for PCNs with RSDs of 7-29% from lard and chicken heart samples, which were used as alternative matrices to harbor seal samples in recovery studies. The limits of detection for OCPs, PCBs and PCNs were 0.7-1.9, 1.5-8.9 and 0.5-10 pg/g dry weight, respectively. This method can be used to analyze OCPs, PCBs and PCNs in harbor seal blubber, liver and kidney samples. PMID:15945031

Wang, Dongli; Atkinson, Shannon; Hoover-Miller, Anne; Li, Qing X

2005-01-01

343

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

344

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

345

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

346

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

347

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

348

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

349

Analysis of natural-occurring and synthetic sexual hormones in sludge-amended soils by matrix solid-phase dispersion and isotope dilution gas chromatography-tandem mass spectrometry.  

PubMed

A sensitive analytical method is presented for the simultaneous determination of four synthetic estrogens and six steroid hormones in sludge-amended soil. The method employs matrix solid-phase dispersion (MSPD) followed by isotope dilution gas chromatography-tandem mass spectrometry injecting a large volume sample (10?L) after trimethylsilyl derivatization, using the solvent vent mode. It affords good resolution, high sensitivity and reproducibility and freedom from interferences even from complex matrices as soil amended with sewage sludge. The limits of detection (LODs) ranged from 10 to 300pgg(-1) with testosterone and progesterone having the highest limits. Soil amended with sewage sludge was spiked at 2, 10, 25 and 50ngg(-1) and the recoveries after MSPD with acetonitrile:methanol (90:10, v/v), ranged from 80 to 110% with relative standard deviations ?9%. The method was applied to the analysis of six soil samples collected from agricultural plots and forested fields that had been amended with sewage sludge using isotopically labeled surrogates. Three of the synthetic estrogens studied were found at least in one of the six samples analyzed and trans-androsterone and estrone were the only natural hormones detected, although at very low levels (?0.4ngg(-1)). PMID:23465128

Albero, Beatriz; Snchez-Brunete, Consuelo; Miguel, Esther; Prez, Rosa A; Tadeo, Jos L

2013-02-08

350

On-line monitoring of benzene air concentrations while driving in traffic by means of isotopic dilution gas chromatography/mass spectrometry.  

PubMed

There is no shortage of information about the average benzene concentrations in urban air, but there is very little about microenvironmental exposure, such as in-vehicle concentrations while driving in various traffic conditions, while refuelling, or while in a parking garage. The main reason for this lack of data is that no analytical instrumentation has been available to measure on-line trace amounts of benzene in such situations. We have recently proposed a highly accurate, high-speed cryofocusing gas chromatography/mass spectrometry (GC/MS) system for monitoring benzene concentrations in air. Accuracy of the analytical data is achieved by enrichment of the air sample before trapping, with a stable isotope permeation tube system. The same principles have been applied to a new instrument, specifically designed for operation on an electric vehicle (Ducato Elettra, Fiat). The zero emission vehicle and the fully transportable, battery-operated GC/MS system provide a unique possibility of monitoring benzene exposure in real everyday situations such as while driving, refuelling, or repairing a car. All power consumptions have been reduced so as to achieve a battery-operated GC/MS system. Liquid nitrogen cryofocusing has been replaced by a packed, inductively heated, graphitized charcoal microtrap. The instrument has been mounted on shock absorbers and installed in the van. The whole system has been tested in both fixed and mobile conditions. The maximum monitoring period without external power supply is 6 h. The full analytical cycle is 4 min, allowing close to real-time monitoring, and the minimum detectable level is 1 microgram/m3 for benzene. In-vehicle monitoring showed that, when recirculation was off and ventilation on, i.e., air from outside the vehicle was blown inside, concentrations varied widely in different driving conditions: moving from a parking lot into normal traffic on an urban traffic condition roadway yielded an increase in benzene concentration from 17 to 62.3 micrograms/m3 even if the actual distance was small. A larger increase was observed when a car was left with the engine running at a distance 2 m from the zero emission vehicle: We measured an increment of benzene concentrations from 15.2 to 174.4 micrograms/m3 with a car equipped with a catalytic converter, and from 19.1 to 386.3 micrograms/m3 with a car without such a converter. PMID:8738357

Davoli, E; Cappellini, L; Moggi, M; Ferrari, S; Fanelli, R

1996-01-01

351

Development of AN Analytical Method Based on Isotope Dilution Gas Chromatography - Mass Spectrometry for the Determination of Trace Quantities of Aqueous Dimethyl Sulfide and Dimethyl Sulfoxide: Application to Rain and Sea Water.  

NASA Astrophysics Data System (ADS)

This dissertation reports the development of a method for determining trace quantities of aqueous dimethyl sulfide (DMS) and dimethyl sulfoxide (DMSO) by isotope dilution gas chromatography - mass spectrometry (GC/MS). Dimethyl sulfide was determined directly, while DMSO was determined indirectly by first reducing DMSO to DMS in situ with sodium borohydride, and subsequently determining the DMS yield. A Purge and trap method was used to strip DMS from solution and cryogenically preconcentrate DMS in unpacked teflon traps. Samples were collected at remote locations and cryogenically preserved in liquid nitrogen for transport to and analysis in the GC/MS laboratory at Drexel University. Perdeuterated DMS (d_6-DMS) and DMSO (d _6-DMSO) were used as internal standards for the determination of DMS and DMSO, respectively. The standards were prepared as ethylene glycol solutions. The precision of this method for determining both DMS and DMSO was +/-2-3%. The relationship between DMS and DMSO isotopomer aqueous concentration ratios and DMS isotopomer MS signal ratios was determined by calibrating the signal ratios as a function of concentration ratios for samples collected from test solutions prepared by adding known quantities of each isotopomer to solution. The ability of this method for determining true solution phase DMS concentrations was demonstrated by plotting the DMS signal ratio as a function of the volume of purge gas passing through solution. Extrapolation of this curve to zero purge gas yielded an intercept ratio that was statistically equivalent to the signal obtained after only a small volume (10 1) of purge gas passed through solution. The detection limit of the DMSO determination was 15 pM. The detection limit of the DMS determination was <10 pM. These methods were applied to the determination of DMS and DMSO in sea water and the determination of DMSO in rain. Dimethyl sulfide determinations made during two research cruises are reported. In addition, sampling procedures such as sample storage and sample filtration were investigated. The DMSO concentration found in rain was ca. 2-4 nM for samples collected at inland locations (Phila. PA) and 8-10 nM for samples collected at coastal locations (Lewes DE).

Ridgeway, Robert Gordon

1991-02-01

352

Diluted magnetic semiconductors  

Microsoft Academic Search

Diluted magnetic semiconductors (DMSs), i.e. semiconducting crystals whose lattice is made up in part of substitutional magnetic ions (e.g. Cd1-xMnxTe, Hg1-xFex Se, Zn1-xCoxS), are reviewed. The focus is on materials of the type A1-xII MnxB VI, which are the most thoroughly understood. However, the similarities and differences between these materials and the A1-x IIFexBVI and A1-IICoxBVI systems are discussed wherever

Nitin Samarth; J. K. Furdyna

1990-01-01

353

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

354

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

355

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

356

Dilution apparatus and method  

SciTech Connect

This patent describes a process for the secondary and tertiary recovery of oil from an oil-bearing subterranean formation having at least one input well and at least one output well which process includes the preparation of an aqueous solution of a polymer consisting essentially of a partially hydrolyzed polyacrylamide capable of meeting the performance demands of an oil-bearing subterranean formation. The polymer solution is introduced. The step of diluting the aqueous polymer solution has a polymer concentration such that the solution has a gel-like consistency to provide an aqueous polymer solution, with a substantially non-gel-like consistency while at the same time minimizing polymer degradation as the aqueous polymer solution is undergoing a physical change from a gel-like consistency to a substantially non gel-like consistency. This enables the partially hydrolyzed polyacrylamide to to retain its capability for meeting the performance demands of an oil-bearing formation into which an aqueous solution containing the polymer is introduced. The dilution is carried out by continuously dispersing an aqueous solution of the polymer of known concentration having a gel-like consistency into a chamber, having an inlet and an outlet, by passing the polymer solution through distributor means at the inlet of the chamber to increase the surface area of the gel-like polymer solution.

Luetzelschwab, W.E.

1987-07-14

357

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

358

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 corrosive gases and liquids.

Cummings, J.C.

1981-01-01

359

Dispersion serial dilution methods using the gradient diluter device.  

PubMed

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

Walling, Leslie; Schulz, Craig; Johnson, Michael

2012-02-24

360

Process and apparatus for igniting a burner in an inert atmosphere  

DOEpatents

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

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

1994-01-01

361

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

SciTech Connect

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

Mehra, Y.R.

1987-07-14

362

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

SciTech Connect

Excess actinides result from the dismantlement of nuclear weapons (Pu) and the reprocessing of commercial spent nuclear fuel (mainly 241 Am, 244 Cm and 237 Np). In Europe, Canada and Japan studies have determined much improved efficiencies for burnup of actinides using inert-matrix fuels. This innovative approach also considers the properties of the inert-matrix fuel as a nuclear waste form for direct disposal after one-cycle of burn-up. Direct disposal can considerably reduce cost, processing requirements, and radiation exposure to workers.

Rodney C. Ewing; Lumin Wang

2002-10-30

363

Constraining Inert Dark Matter by R ?? and WMAP data  

NASA Astrophysics Data System (ADS)

We discuss the constraints on Dark Matter coming from the LHC Higgs data and WMAP relic density measurements for the Inert Doublet Model, which is one of the simplest extensions of the Standard Model providing a Dark Matter candidate. We found that combining the diphoton rate R ?? and the ? DM h 2 data one can set strong limits on the parameter space of the Inert Doublet Model, stronger or comparable to the constraints provided by the XENON100 experiment for low and medium Dark Matter mass.

Krawczyk, Maria; Soko?owska, Dorota; Swaczyna, Pawe?; ?wie?ewska, Bogumi?a

2013-09-01

364

Signals of inert doublet dark matter in neutrino telescopes  

SciTech Connect

One of the simplest extensions of the standard model that explains the observed abundance of dark matter is the inert doublet model. In this theory a discrete symmetry ensures that the neutral component of an additional electroweak doublet scalar is stable and constitutes a dark matter candidate. As massive bodies such as the Sun and Earth move through the dark matter halo, dark matter particles can become gravitationally trapped in their cores. Annihilations of these particles result in neutrinos, which can potentially be observed with neutrino telescopes. We calculate the neutrino detection rate at these experiments from inert doublet dark matter annihilations in the cores of the Sun and the Earth.

Agrawal, Prateek [Department of Physics, University of Maryland, College Park, Maryland 20742 (United States); Dolle, Ethan M. [Department of Physics, University of Arizona, Tucson, Arizona 85721 (United States); Krenke, Christopher A. [Department of Physics, University of Maryland, College Park, Maryland 20742 (United States); Department of Physics, University of Arizona, Tucson, Arizona 85721 (United States)

2009-01-01

365

Removal of sulfur dioxide from a continuously operated binary fluidized bed reactor using inert solids and hydrated lime  

Microsoft Academic Search

Sulfur dioxide pollutant was treated in the laboratory with hydrated lime particles having a mean diameter of 9.1?m in a continuously operating binary fluidized bed reactor also containing inert sand particles with sizes varying from 500 to 590?m. The influence of temperature (500, 600, 700 and 800C) on the reaction medium, of the superficial velocity of the gas (0.8, 1.0

R. Pisani; D. de Moraes

2004-01-01

366

Dilution refrigerator for muon spin relaxation experiments  

SciTech Connect

The design, construction, and operational characteristics of a continuous THe--UHe dilution refrigerator specifically built for use in muon spin relaxation ( SR) measurements at LAMPF are described in this paper. The refrigerator is unique in that it makes an angle of 30 with respect to horizontal: a requirement imposed by the previously existing physical constraints of the SR spectrometer. Additionally, the refrigerator and associated gas handling units are portable so as to facilitate ease of movement into and out of the muon beam. Typical parameters describing refrigerator performance are 60-mK base temperature with 22- W cooling capacity at 100 mK.

Cooke, D.W.; Hoffer, J.K.; Maez, M.; Steyert, W.A.; Heffner, R.H.

1986-03-01

367

Dilution physics modeling: Dissolution/precipitation chemistry  

SciTech Connect

This report documents progress made to date on integrating dilution/precipitation chemistry and new physical models into the TEMPEST thermal-hydraulics computer code. Implementation of dissolution/precipitation chemistry models is necessary for predicting nonhomogeneous, time-dependent, physical/chemical behavior of tank wastes with and without a variety of possible engineered remediation and mitigation activities. Such behavior includes chemical reactions, gas retention, solids resuspension, solids dissolution and generation, solids settling/rising, and convective motion of physical and chemical species. Thus this model development is important from the standpoint of predicting the consequences of various engineered activities, such as mitigation by dilution, retrieval, or pretreatment, that can affect safe operations. The integration of a dissolution/precipitation chemistry module allows the various phase species concentrations to enter into the physical calculations that affect the TEMPEST hydrodynamic flow calculations. The yield strength model of non-Newtonian sludge correlates yield to a power function of solids concentration. Likewise, shear stress is concentration-dependent, and the dissolution/precipitation chemistry calculations develop the species concentration evolution that produces fluid flow resistance changes. Dilution of waste with pure water, molar concentrations of sodium hydroxide, and other chemical streams can be analyzed for the reactive species changes and hydrodynamic flow characteristics.

Onishi, Y.; Reid, H.C.; Trent, D.S.

1995-09-01

368

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

SciTech Connect

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

P. McIntyre and S. Seshadri

2008-06-20

369

Explosion propagation in inert porous media.  

PubMed

Porous media are often used in flame arresters because of the high surface area to volume ratio that is required for flame quenching. However, if the flame is not quenched, the flow obstruction within the porous media can promote explosion escalation, which is a well-known phenomenon in obstacle-laden channels. There are many parallels between explosion propagation through porous media and obstacle-laden channels. In both cases, the obstructions play a duel role. On the one hand, the obstruction enhances explosion propagation through an early shear-driven turbulence production mechanism and then later by shock-flame interactions that occur from lead shock reflections. On the other hand, the presence of an obstruction can suppress explosion propagation through momentum and heat losses, which both impede the unburned gas flow and extract energy from the expanding combustion products. In obstacle-laden channels, there are well-defined propagation regimes that are easily distinguished by abrupt changes in velocity. In porous media, the propagation regimes are not as distinguishable. In porous media the entire flamefront is affected, and the effects of heat loss, turbulence and compressibility are smoothly blended over most of the propagation velocity range. At low subsonic propagation speeds, heat loss to the porous media dominates, whereas at higher supersonic speeds turbulence and compressibility are important. This blending of the important phenomena results in no clear transition in propagation mechanism that is characterized by an abrupt change in propagation velocity. This is especially true for propagation velocities above the speed of sound where many experiments performed with fuel-air mixtures show a smooth increase in the propagation velocity with mixture reactivity up to the theoretical detonation wave velocity. PMID:22213663

Ciccarelli, G

2012-02-13

370

Reactor physics aspects of plutonium burning in inert matrix fuels  

Microsoft Academic Search

Burnup calculations have been performed on fuels containing either reactor grade or weapons grade plutonium mixed in an inert matrix or mixed in a thorium oxide matrix. At each branching during burnup, the fuel temperature coefficient, the moderator void coefficient and the boron reactivity worth have been calculated. From the reactor physics point of view, use of thorium oxide as

J. L. Kloosterman; P. M. G. Damen

1999-01-01

371

Inert Electrodes Program fiscal year 1988 annual report  

SciTech Connect

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

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

1989-10-01

372

Thoria and inert matrix fuels for a sustainable nuclear power  

Microsoft Academic Search

Nuclear power to be sustainable requires the fulfilling of peculiar constraints, which include addressing the proliferation risk. One possible route for sustainability is that to adopt a fuel cycle based on thorium. However, comparison with uranium cycle indicates that thorium cycle utilization is premature. Instead, a promising short-term option is the use of inert matrix fuels, possibly containing thoria, in

C. Lombardi; L. Luzzi; E. Padovani; F. Vettraino

2008-01-01

373

A Limit Theorem for Financial Markets with Inert Investors  

Microsoft Academic Search

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

Erhan Bayraktar; Ulrich Horst; Ronnie Sircar

2007-01-01

374

A NOVEL INERT COLLAGEN MATRIX FOR HYPOSPADIAS REPAIR  

Microsoft Academic Search

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

ANTHONY ATALA; LUIS GUZMAN; ALAN B. RETIK

1999-01-01

375

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

National Technical Information Service (NTIS)

A process description and system flow sheets have been prepared to support the design/build package for the Shippingport Spent Fuel Canister (SSFC) drying and inerting process skid. A process flow diagram was prepared to show the general steps to dry and ...

2002-01-01

376

INERT GASES AND THE EVOLUTION OF THE ATMOSPHERE  

Microsoft Academic Search

The origin of the present isotopic composition of the inert gases in the ; atmosphere is reviewed. Using new data on the maximum rate of tritium, and hence ; He³, production in the atmosphere, the present rate of escape of He⁴ ; and Ar⁴° from the crust can be calculated. It is found that this rate is ; far too

P. E. Damon; J. L. Kulp

1958-01-01

377

How the dynamics of an ablation plume is affected by ambient gas ionisation  

Microsoft Academic Search

The influence of inert gas ionisation on the expansion dynamics of a laser ablation plume propagating through an inert gas is studied. Charge transfer reactions between ionised ablated species and gas neutrals lead to the formation of a charged layer of ionised gas atoms in contact with the plume expansion front. The energy lost by fast ablated ions when the

A. Bailini; P. M. Ossi

2005-01-01

378

Experimental study on the solid velocity in horizontal dilute phase pneumatic conveying of fine powders  

Microsoft Academic Search

The calculation reliability of pressure drop and gassolid drag force in horizontal dilute phase pneumatic conveying strongly depends on the accuracy of gassolid velocity correlation. However, there are limited studies on the solid velocity in horizontal dilute phase pneumatic conveying and it is important to further validate suitability of existing correlation of gassolid velocity, especially for fine particles (such as

Wang Wei; Guan Qingliang; Wu Yuxin; Yang Hairui; Zhang Jiansheng; Lu Junfu

2011-01-01

379

Dilute Oxygen Combustion - Phase 3 Report  

SciTech Connect

Dilute Oxygen Combustion (DOC) burners have been successfully installed and operated in the reheat furnace at Auburn Steel Co., Inc., Auburn, NY, under Phase 3 of the Dilute Oxygen Combustion project. Two new preheat zones were created employing a total of eight 6.5 MMBtu/hr capacity burners. The preheat zones provide a 30 percent increase in maximum furnace production rate, from 75 tph to 100 tph. The fuel rate is essentially unchanged, with the fuel savings expected from oxy-fuel combustion being offset by higher flue gas temperatures. When allowance is made for the high nitrogen level and high gas phase temperature in the furnace, measured NOx emissions are in line with laboratory data on DOC burners developed in Phase 1 of the project. Burner performance has been good, and there have been no operating or maintenance problems. The DOC system continues to be used as part of Auburn Steel's standard reheat furnace practice. High gas phase temperature is a result of the high firing density needed to achieve high production rates, and little opportunity exists for improvement in that area. However, fuel and NOx performance can be improved by further conversion on furnace zones to DOC burners, which will lower furnace nitrogen levels. Major obstacles are cost and concern about increased formation of oxide scale on the steel. Oxide scale formation may be enhanced by exposure of the steel to higher concentrations of oxidizing gas components (primarily products of combustion) in the higher temperature zones of the furnace. Phase 4 of the DOC project will examine the rate of oxide scale formation in these higher temperature zones and develop countermeasures that will allow DOC burners to be used successfully in these furnace zones.

Riley, Michael F.

2000-05-31

380

Dilute Oxygen Combustion Phase 3 Final Report  

SciTech Connect

Dilute Oxygen Combustion (DOC) burners have been successfully installed and operated in the reheat furnace at Auburn Steel Co., Inc., Auburn, NY, under Phase 3 of the Dilute Oxygen Combustion project. Two new preheat zones were created employing a total of eight 6.5 MMBtu/hr capacity burners. The preheat zones provide a 30 percent increase in maximum furnace production rate, from 75 tph to 100 tph. The fuel rate is essentially unchanged, with the fuel savings expected from oxy-fuel combustion being offset by higher flue gas temperatures. When allowance is made for the high nitrogen level and high gas phase temperature in the furnace, measured NOx emissions are in line with laboratory data on DOC burners developed in Phase 1 of the project. Burner performance has been good and there have been no operating or maintenance problems. The DOC system continues to be used as part of Auburn Steel?s standard reheat furnace practice. High gas phase temperature is a result of the high firing density needed to achieve high production rates, and little opportunity exists for improvement in that area. However, fuel and NOx performance can be improved by further conversion of furnace zones to DOC burners, which will lower furnace nitrogen levels. Major obstacles are cost and concern about increased formation of oxide scale on the steel. Oxide scale formation may be enhanced by exposure of the steel to higher concentrations of oxidizing gas components (primarily products of combustion) in the higher temperature zones of the furnace. Phase 4 of the DOC project will examine the rate of oxide scale formation in these higher temperature zones and develop countermeasures that will allow DOC burners to be used successfully in these furnace zones.

Riley, M.F.; Ryan, H.M.

2000-05-31

381

the Metal Abundance of X-ray Faint Early-Type Galaxies: Effects of Dilution?  

NASA Astrophysics Data System (ADS)

The metallicity of hot gas in E/S0 galaxies is known to vary widely, in the sense that galaxies with only small amounts of hot gas often have very low hot gas metallicities. One solution is that what little hot gas X-ray faint systems have has been diluted by pristine hydrogen gas in the vicinity of the galaxy. There is a growing body of evidence suggesting that some early-type galaxies harbor sizable large-scale HI halos, presumably left over from the epoch of galaxy formation. If this pristine HI is accreted, the existing hot gas in the galaxy will be diluted. We propose to test this by measuring the metallicities of a sample of X-ray faint galaxies with a range of HI-to-hot gas ratios. If the dilution hypothesis is correct, galaxies with more HI will have lower hot gas metallicities.

Su, Yuanyuan

2010-10-01

382

Design of a compact dilution sampler for stationary combustion sources.  

PubMed

The dilution sampling method simulates the rapid cooling and dilution processes after hot flue gas have left the stack. This allows gases or vapors to nucleate both homogeneously and heterogeneously, and to condense on preexisting particles in processes analogous to those that occur in the ambient environment. Using this method the authors can collect filterable particulate matter (PM) and condensible PM, that is, primary PM, simultaneously. In order to make this method more suitable for field investigation, a compact dilution sampler was developed. The sampler enhances mixing of dilution air with the stack gas, and thus shortens the length of the mixing section. The design decreases the nominal flow rate through the aging section, and accordingly reduces the size of the residence chamber. The decreased size of the sampler is suitable for field test. Sampling gas is pressured into the residence chamber, and air pressure in the chamber is micro-positive. Uncollected redundant gas is automatically discharged through unused sampling ports, which keeps the unit stable. Performance evaluation tests demonstrate that the design is reasonable. The sampler has been applied to characterize PM emissions from various combustion sources in China. PMID:22168096

Li, Xinghua; Wang, Shuxiao; Duan, Lei; Hao, Jiming; Long, Zhengwei

2011-11-01

383

FIELD AND LABORATORY EVALUATION OF A WOODSTOVE DILUTION SAMPLING SYSTEM  

EPA Science Inventory

The paper discusses field and laboratory evaluation of a woodstove dilution sampling system. Two sampling methods have been developed and used by EPA to test emissions from woodstoves: both remove flue gas directly from the appliance chimney. The two methods have been developed t...

384

A miniature dilution refrigerator for sub-Kelvin detector arrays  

Microsoft Academic Search

We describe a miniature dilution refrigerator (MDR), operated in continuous mode and suitable for many detector applications at temperatures down to 50 mK. It distinguishes itself from other refrigerators in that it is self-contained and benefits from an internal cycle of the 3He gas. As a result, no external gas handling system is required so size, weight and complexity of

Gustav Teleberg; Simon T. Chase; Lucio Piccirillo

2006-01-01

385

Benefit Analysis for Nitrogen Inerting of Aircraft Fuel Tanks against Ground Fire Explosion.  

National Technical Information Service (NTIS)

The objective of this analysis was to access the potential benefits, in terms of reducing fatalities and injuries, resulting from three methods of aircraft fuel tank inerting. The methods analyzed were ground nitrogen inerting in center fuel tank only, gr...

R. Cherry K. Warren

1999-01-01

386

Species-specific isotope dilution analysis of mono-, di, and tri-butyltin compounds in sediment using gas chromatography-inductively coupled plasma mass spectrometry with synthesized 118Sn-enriched butyltins.  

PubMed

A species-specific isotope dilution (ID) method is described for the determination of mono-, di, and tri-butyltin compounds in sediment by gas chromatography-inductively coupled plasma mass spectrometry (GC-ICP-MS), where the mixture of 118Sn-enriched butyltin compounds synthesized in our laboratory was used as a spike. A correction method for the mass bias, a quantitative extraction of the butyltins from sediment, and an assay for the concentration of the standard solution for the reverse ID procedure were investigated to achieve a reliable ID analysis. The spike solution was added with tri-propyltin (TPrT), and the butyltins were extracted by mechanical shaking into acetic acid-tropolone-toluene. The extracted butyltins were ethylated with sodium tetraethylborate and measured by GC-ICP-MS. The mass bias correction factor for the butyltins was calculated with the measured area ratio of 120Sn/118Sn of TPrT in each chromatographic run, and the correction was carried out. The mass bias was well corrected with this in-run correction (the standard uncertainties of the corrected 120Sn/118Sn for the butyltins were in the range 0.03-0.45%, typically 0.25%, with triplicate measurement corresponding to 0.02-0.37% mass bias). The extraction efficiency of mono-butyltin (MBT) from sediment was improved by using tropolone-toluene as the solvent. Well-defined standard solutions for the reverse-ID procedure could be obtained by an assay for the purities of the natural abundance butyltin chloride reagents used for preparing the standard solutions. Overall uncertainties associated with the present method were estimated, where the sediment certified reference materials, PACS-2 and BCR 646, were analyzed. The uncertainty arising from the extraction was the main contributor to the overall uncertainties for MBT and di-butyltin (DBT) determinations, while with the case of tri-butyltin (TBT) determination the uncertainties arising from the purity of TBT chloride reagent used for preparing the standard solution was a large contributor to the overall uncertainties although the uncertainty arising from the extraction was also a main contributor. The analytical results of MBT, DBT, and TBT in both reference materials, except for MBT results in PACS-2, were in good agreement with the certified values in each. The result of MBT in PACS-2 (0.677 +/- 0.049 microg g(-1) as tin, mean +/- expanded uncertainty) was significantly higher than the certified value (0.45 +/- 0.05 microg g(-1)), but closely matched with the lately reported values (Rajendran, Tao, Nakazato and Miyazaki, Analyst, 2000, 125, 1757: 0.62 +/- 0.02 microg g(-1); Chiron, Roy, Cottier and Jeannot, J. Chromatogr. A, 2000, 879, 137: 0.634 +/- 0.082 microg g(-1); Alonso, Encinar, Gonzalez and Sanz-Medal, Anal. Bioanal. Chem., 2002, 373, 432: 0.64 +/- 0.04 microg g(-1). The present method is concluded to be reliable for the determination of MBT, DBT, and TBT in sediment. PMID:12705386

Inagaki, Kazumi; Takatsu, Akiko; Watanabe, Takuro; Aoyagi, Yoshie; Okamoto, Kensaku

2003-03-01

387

DETERMINATION OF INFINITE DILUTION ACTIVITY COEFFICIENTS FOR ORGANIC-AQUEOUS SYSTEMS USING A DILUTE VAPOR-LIQUID EQUILIBRIUM METHOD  

Microsoft Academic Search

A low pressure vapor-liquid equilibrium apparatus has been developed, tested and verified for the measurements of dilute solution activity coefficients for different organic solutes in aqueous systems. Activity coefficient data were measured for aqueous binary mixtures involving methanol, acetone, and benzene at 25C. The experimental measurements targeted the range of solute liquid compositions extending from the Gas Chromalograph detection limit

M. S. H. BADER; K. A. M. GASEM

1995-01-01

388

Computational model for prediction of particle degradation during dilute-phase pneumatic conveying: modeling of dilute-phase pneumatic conveying  

Microsoft Academic Search

A complete model of particle impact degradation during dilute-phase pneumatic conveying is developed, which combines a degradation model, based on the experimental determination of breakage matrices, and a physical model of solids and gas flow in the pipeline. The solids flow in a straight pipe element is represented by a model consisting of two zones: a strand-type flow zone immediately

Pierre Chapelle; Nicholas Christakis; Hadi Abou-Chakra; Ian Bridle; M. S. A. Bradley; Mayur Patel; Mark Cross

2004-01-01

389

The Optimum Plutonium Inert Matrix Fuel Form for Reactor-Based Plutonium Disposition  

SciTech Connect

The University of Florida has underway an ongoing research program to validate the economic, operational and performance benefits of developing an inert matrix fuel (IMF) for the disposition of the U.S. weapons plutonium (Pu) and for the recycle of reprocessed Pu. The current fuel form of choice for Pu disposition for the Department of Energy is as a mixed oxide (MOX) (PuO2/UO2). We will show analyses that demonstrate that a Silicon Carbide (SiC) IMF offers improved performance capabilities as a fuel form for Pu recycle and disposition. The reason that UF is reviewing various materials to serve as an inert matrix fuel is that an IMF fuel form can offer greatly reduced Pu and transuranic isotope (TRU) production and also improved thermal performance characteristics. Our studies showed that the Pu content is reduced by an order of magnitude while centerline fuel temperatures are reduced approximately 380 degrees centigrade compared to MOX. These reduced temperatures result in reduced stored heat and thermal stresses in the pellet. The reduced stored heat reduces the consequences of the loss of coolant accident, while the reduced temperatures and thermal stresses yield greatly improved fuel performance. Silicon Carbide is not new to the nuclear industry, being a basic fuel material in gas cooled reactors.

Tulenko, J.S.; Wang, J.; Acosta, C.

2004-10-06

390

The Optimum Plutonium Inert Matrix Fuel Form for Reactor-Based Plutonium Disposition  

SciTech Connect

The University of Florida has underway an ongoing research program to validate the economic, operational and performance benefits of developing an inert matrix fuel (IMF) for the disposition of the U.S. weapons plutonium (Pu) and for the recycle of reprocessed Pu. The current fuel form of choice for Pu disposition for the Department of Energy is as a mixed oxide (MOX) (PuO2/UO2). We will show analyses that demonstrate that a Silicon Carbide (SiC) IMF offers improved performance capabilities as a fuel form for Pu recycle and disposition. The reason that UF is reviewing various materials to serve as an inert matrix fuel is that an IMF fuel form can offer greatly reduced Pu and transuranic isotope (TRU) production and also improved thermal performance characteristics. Our studies showed that the Pu content is reduced by an order of magnitude while centerline fuel temperatures are reduced approximately 380 degrees centigrade compared to MOX. These reduced temperatures result in reduced stored heat and thermal stresses in the pellet. The reduced stored heat reduces the consequences of the loss of coolant accident, while the reduced temperatures and thermal stresses yield greatly improved fuel performance. Silicon Carbide is not new to the nuclear industry, being a basic fuel material in gas cooled reactors.

Tulenko, J.S.; Wang, J.; Acosta, C.

2004-10-03

391

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

PubMed

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

Chandrasekaran, Sriraam R; Hopke, Philip K

2012-09-04

392

Inert-sterile neutrino: Cold or warm dark matter candidate  

SciTech Connect

In usual particle models, sterile neutrinos can account for the dark matter of the Universe only if they have masses in the keV range and are warm dark matter. Stringent cosmological and astrophysical bounds, in particular, imposed by x-ray observations, apply to them. We point out that in a particular variation of the inert doublet model, sterile neutrinos can account for the dark matter in the Universe and may be either cold or warm dark matter candidates, even for masses much above the keV range. These inert-sterile neutrinos, produced nonthermally in the early Universe, would be stable and have very small couplings to standard model particles, rendering very difficult their detection in either direct or indirect dark matter searches. Their existence could be revealed only by discovering other particles of the model in collider experiments.

Gelmini, Graciela B.; Osoba, Efunwande [Department of Physics and Astronomy, UCLA, 475 Portola Plaza, Los Angeles, California 90095 (United States); Palomares-Ruiz, Sergio [Centro de Fisica Teorica de Particulas (CFTP), Instituto Superior Tecnico, P-1049-001, Lisboa (Portugal)

2010-03-15

393

Improved electroweak phase transition with subdominant inert doublet dark matter  

NASA Astrophysics Data System (ADS)

The inert doublet dark matter model has recently gained attention as a possible means of facilitating a strongly first-order electroweak phase transition (EWPT), as needed for baryogenesis. We extend previous results by considering the regime where the DM is heavier than half the Higgs mass, and its relic density is determined by annihilation into W, Z and Higgs bosons. We find a large natural region of parameter space where the EWPT is strongly first order, while the lightest inert doublet state typically contributes only 0.1%-3% of the total dark matter. Despite this small density, its interactions with nucleons are strong enough to be directly detectable given a factor of 5 improvement over the current sensitivity of XENON100. A 10% increase in the branching ratio for Higgs decays to two photons is predicted.

Cline, James M.; Kainulainen, Kimmo

2013-04-01

394

Thermodynamics of Extremely Diluted Aqueous Solutions  

Microsoft Academic Search

An extensive thermodynamic study has been carried out on aqueous solutions ob- tained through successive dilutions and succussions of 1% wt\\/vol of some solutes up to extremely diluted solutions, (less than l 10?5 mol kg?1 ) obtained via several 1\\/ 100 successive dilution processes. The interaction of acids or bases with the ex- tremely diluted solutions has been studied

Vittorio Elia; Marcella Niccoli

1999-01-01

395

Inert supports for lactic acid fermentation a technological assessment  

Microsoft Academic Search

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

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

1992-01-01

396

Biodiesel Impact on Engine Lubricant Dilution During Active Regeneration of Aftertreatment Systems  

Microsoft Academic Search

Experiments were conducted with ultra low sulfur diesel (ULSD) and 20% biodiesel blends (B20) to compare lube oil dilution levels and lubricant properties for systems using late in-cylinder fuel injection for aftertreatment regeneration. Lube oil dilution was measured by gas chromatography (GC) following ASTM method D3524 to measure diesel content, by Fourier transform infrared (FTIR) spectrometry following a modified ASTM

X. He; A. Williams; E. Christensen; J. Burton; R. McCormick

2011-01-01

397

Numerical investigation of the ignition of dilute fuel sprays including detailed chemistry  

Microsoft Academic Search

One-dimensional unsteady numerical calculations have been performed to study the ignition of dilute fuel sprays. Recent investigations in this field employ global kinetic rate expressions to model the chemical reactions occurring in the gas phase. In the present paper a detailed kinetic mechanism is employed to describe the ignition process of dilute methanol sprays in air, the mechanism for methanol

E GUTHEIL

1993-01-01

398

Bose-Einstein condensation experiment in a dilute vapor of rubidium  

Microsoft Academic Search

Over 70 years ago, Einstein predicted, based on the statistical arguments of Bose, that a dilute gas of integer spin particles exhibits a fundamentally quantum mechanical phase transition at low temperatures, the Bose-Einstein condensation (BEC). Only in the last two years has this novel state of matter been created in dilute atomic systems, in direct correspondence to Einstein's original conjecture.

Christopher John Myatt

1997-01-01

399

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

Federal Register 2010, 2011, 2012, 2013

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

2010-01-05

400

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

DOEpatents

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

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

2000-01-01

401

Experimental study on a high frequency miniature pulse tube refrigerator with inertance tube  

Microsoft Academic Search

It is generally considered that the use of an inertance tube in a high frequency pulse tube refrigerator (PTR) improves the phase shift between the pressure and the mass flow rate. In order to investigate the effects of inertance tubes on the performance of a miniature PTR, experiments on the high frequency miniature PTR with inertance tube, orifice and bypass

Y. K. Hou; Y. L. Ju; L. W. Yan; J. T. Liang; Y. Zhou

2002-01-01

402

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

Microsoft Academic Search

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

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

2000-01-01

403

Solute Retention in Column Liquid Chromatography. X. Determination of Solute Infinite-Dilution Activity Coefficients in Methanol, Water, and Their Mixtures, by Combined Gas-Liquid and Liquid-Liquid Chromatography  

Microsoft Academic Search

The Raoult's-law activity coefficients of 3- to 7-carbon aliphatic aldehyde, ketone, ester, and alcohol solutes at infinite dilution in methanol, water, and mixtures of the two and in polydimethylsiloxane, all at 293308 K, have been determined for the first time by appropriate combination of GLC and LLC retention data. The latter data are reported in terms of mole fractions, while

R. A. Djerki; R. J. Laub

1988-01-01

404

Heavy-Duty Waste Hauler with Chemically Correct Natural Gas Engine Diluted with EGR and Using a Three-Way Catalyst: Final Report, 24 February 2004 -- 23 February 2006  

SciTech Connect

This report discusses the development of a E7G 12-liter, lean-burn natural gas engine--using stoichiometric combustion, cooled exhaust gas recirculation, and three-way catalyst technologies--for refuse haulers.

Reppert, T.; Chiu, J.

2005-09-01

405

Development of a standard bench-scale cell for electrochemical studies on inert anodes. Inert Anode/Cathode Program  

SciTech Connect

Objective of this work was to develop a standard bench-scale cell for performing short-term ac and dc polarization studies on inert anode candidate materials in molten cryolite. Two designs for electrochemical cells were developed and successfully evaluated in short-term experiments. Both cells consisted on the inert anode as a small cylindrical specimen partially sheathed in alumina, an Al/Al/sub 2/O/sub 3/ reference electrode, and a cryolite bath saturated in alumina. The difference between the two cells was in the design of the cathode. One cell used a bare solid metal cathode; the other used an aluminum pad similar to the Hall-Heroult configuration.

Windisch, C.F. Jr.; Boget, D.I.

1986-07-01

406

Association effects in the {methanol + inert solvent} system via Monte Carlo simulations. I. Structure  

NASA Astrophysics Data System (ADS)

In this work, the clusters residing in the {methanol + inert solvent} binary system have been characterized using a specific methodology in the framework of Monte Carlo molecular simulations. The cluster classification scheme considered distinguishes into five types: linear chains, cyclic clusters or isolated rings, branched linear chains, branched cyclic clusters, and composite rings. The procedure allows one to compute the next rich structural information: the fraction of molecules in the monomer or associated state, the fraction of each type of aggregate with a given size (and of molecules belonging to them), and the most probable and average cluster size for each type; likewise, the degree of branching in branched linear chains and the size distribution of the inner ring in branched cyclic clusters can be quantified. Specifically, all these properties were obtained for the {Optimized Potential for Liquid Simulation methanol + Lennard-Jones spheres} system at 298.15 K and 1 bar throughout the composition range. The results have provided a complete structural picture of this mixture describing comprehensively the effect of dilution into the hydrogen-bonded network of the pure associated fluid.

Gmez-lvarez, Paula; Roman, Luis; Gonzlez-Salgado, Diego

2013-05-01

407

Investigation on the Inertance Tubes of Pulse Tube Cryocooler Without Reservoir  

NASA Astrophysics Data System (ADS)

Phase angle is of vital importance for high-efficiency pulse tube cryocoolers (PTCs). Inertance tube as the main phase shifter is useful for the PTCs to obtain appropriate phase angle. Experiments of inertance tube without reservoir under variable frequency, variable length and diameter of inertance tube and variable pressure amplitude are investigated respectively. In addition, the authors used DeltaEC, a computer program to predict the performance of low-amplitude thermoacoustic engines, to simulate the effects of inertance tube without reservoir. According to the comparison of experiments and theoretical simulations, DeltaEC method is feasible and effective to direct and improve the design of inertance tubes.

Liu, Y. J.; Yang, L. W.; Liang, J. T.; Hong, G. T.

2010-04-01

408

Dilution and the elusive baseline.  

PubMed

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

Likens, Gene E; Buso, Donald C

2012-04-05

409

Theory of Magnetically Dilute Systems  

Microsoft Academic Search

The variation of the critical temperature (the Curie or Nel temperature) of a magnetic crystal randomly diluted with non-magnetic atoms is evaluated as a function of concentration p of magnetic atoms by the effective Hamiltonian method based on the Ising and the Heisenberg models. The specific heat of Ising ferromagnet above the Curie temperature is calculated for various concentrations in

Takehiko Oguchi; Takeshi Obokata

1969-01-01

410

Quantitative Analysis by Isotopic Dilution Using Mass Spectroscopy: The Determination of Caffeine by GC-MS.  

ERIC Educational Resources Information Center

Describes a laboratory technique for quantitative analysis of caffeine by an isotopic dilution method for coupled gas chromatography-mass spectroscopy. Discusses caffeine analysis and experimental methodology. Lists sample caffeine concentrations found in common products. (MVL)

Hill, Devon W.; And Others

1988-01-01

411

Quantitative Analysis by Isotopic Dilution Using Mass Spectroscopy: The Determination of Caffeine by GC-MS.  

ERIC Educational Resources Information Center

|Describes a laboratory technique for quantitative analysis of caffeine by an isotopic dilution method for coupled gas chromatography-mass spectroscopy. Discusses caffeine analysis and experimental methodology. Lists sample caffeine concentrations found in common products. (MVL)|

Hill, Devon W.; And Others

1988-01-01

412

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

EPA Science Inventory

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

413

Inert Hugoniot for a porous titanium-Teflon mixture: Experiment and calculations  

NASA Astrophysics Data System (ADS)

A study of shock-induced reactions in metal-polymer mixtures via a series of gas gun experiments have been performed. Tests on a mixture of titanium and Teflon which is by weight 80% Ti and 20% Teflon and approximately 92.5% of theoretical maximum density showed reactivity at 3.48 GPa and above. PVDF gauges were used to determine the pressure at the sample/driver interface. Some of the tests were performed with a second PVDF gauge embedded further in the sample to measure reaction. Impedance matching technique was used to determine the inert Hugoniot. A series of calculations were performed to determine the calculation model which best mimics the experimentally determined Hugoniot. The results from the calculations show that an isotherm mixture model matches well the experimental results over the low and middle pressure range studied.

Davis, J. J.; Lindfors, A. J.

1998-07-01

414

Inert Hugoniot for a porous titanium - Teflon mixture: Experiment = and calculations  

NASA Astrophysics Data System (ADS)

A study of shock induced reactions in metal - polymer mixtures via a series of gas gun experiments have been performed. Tests on a mixture of titanium and Teflon which is by weight 80% Ti and 20% Teflon showed reactivity. These were at approximately 92% of theoretical maximum density. PVDF gauges were used to determine the pressure at the sample/driver interface and the pressure further in the sample via an embedded gauge. The impedance matching technique was used to determine the inert Hugoniot. Along with the experiments, a series of calculations were performed to determine which calculational model best mimics the experimentally determined Hugoniot. Several different approaches were tried. The results from the calculations show that an isotherm mixture model matchs well the experimental results. The experimental and modeling results will be presented and discussed along for results for other metal - polymer systems.

Davis, Jeff; Lindfors, Allen

1997-07-01

415

Extraordinary temperature dependence of isochoric thermal conductivity of crystalline CO2 doped with inert gases  

NASA Astrophysics Data System (ADS)

The isochoric thermal conductivities of the solid solutions (CO2)0.905Kr0.095 and (CO2)1-xXex (x=0.052 and 0.097) of different densities are investigated in the temperature interval from 150 K to the onset of melting. An unusual effect of point defects on the thermal conductivity has been detected. In pure CO2 at T>150 K the isochoric thermal conductivity decreases smoothly with increasing temperature. In contrast, the thermal conductivity of CO2/Kr and CO2/Xe solid solutions first decreases, passing through a minimum at 200-210 K, and then starts to increase with temperature up to the onset of melting. This behavior of the isochoric thermal conductivity is attributed to the rotation of the CO2 molecules, which gain more freedom as the spherically symmetrical inert gas atoms are dissolved in the CO2.

Konstantinov, V. A.; Manzhelii, V. G.; Revyakin, V. P.; Sagan, V. V.

2006-11-01

416

Neutron scattering study of dilute supercritical solutions  

SciTech Connect

Dilute solutions in supercritical solvents exhibit interesting microstructures that are related to their dramatic macroscopic behavior. In typical attractive solutions, solutes are believed to be surrounded by clusters of solvent molecules, and solute molecules are believed to congregate in the vicinity of one another. Repulsive solutions, on the other hand, exhibit a local region of reduced solvent density around the solute with solute-solute congregation. Such microstructures influence solubility, partial molar volume, reaction kinetics, and many other properties. We have undertaken to observe these interesting microstructures directly by neutron scattering experiments on dilute noble gas systems including Ar. The three partial structure factors for such systems and the corresponding pair correlation functions can be determined by using the isotope substitution technique. The systems studied are uniquely suited for our objectives because of the large coherent neutron scattering length of the isotope {sup 36}Ar and because of the accurate potential energy functions that are available for use in molecular simulations and theoretical calculations to be compared with the scattering results. We will describe our experiment, the unique apparatus we have built for it, and the neutron scattering results from our initial allocations of beam time. We will also describe planned scattering experiments to follow those with noble gases, including study of long-chain molecules in supercritical solvents. Such studies will involve hydrocarbon mixtures with and without deuteration to provide contrast.

Cochran, H.D.; Wignall, G.D. [Oak Ridge National Lab., TN (United States); Shah, V.M.; Londono, J.D.; Bienkowski, P.R. [Univ., of Tennessee, Knoxville, TN (United States). Dept. of Chemical Engineering

1994-10-01

417

Development of improved technologies and techniques for reducing base gas requirements in underground gas storage facilities: Simulation study of hanson field gas storage reservoir. Final report, May 1989November 1989  

Microsoft Academic Search

Base gas requirements in the U.S. amount to a few trillion cubic feet. The Gas Research Institute has proposed a gas storage operating plan whereby an inert gas or a low BTU gas could be injected to replace part of the hydrocarbon gas. A reservoir simulator has been developed, enhanced and tested to solve gas-water reservoir problems where the gas

Modine

1989-01-01

418

Application of Cryocoolers to a Vintage Dilution Refrigerator  

SciTech Connect

A dilution refrigerator is required for 50mK detector operation of CDMS (Cryogenic Dark Matter Search). Besides shielding the dilution refrigerator itself, the liquid nitrogen shield and liquid helium bath in the refrigerator cool the detector cryostat heat shields and cool electronics, resulting in significant external heat loads at 80K and at 4K. An Oxford Instruments Kelvinox 400 has served this role for ten years but required daily transfers of liquid nitrogen and liquid helium. Complicating the cryogen supply is the location 800 meters below ground in an RF shielded, class 10000 clean room at Soudan, MN. Nitrogen and helium re-liquefiers using cryocoolers were installed outside the clean room and continuously condense room temperature gas and return the liquids to the dilution refrigerator through a transfer line. This paper will describe the design, installation, controls and performance of liquefaction systems.

Schmitt, Richard; Smith, Gary; Ruschman, Mark; /Fermilab; Beaty, Jim; /Minnesota U.

2011-06-06

419

Inert Electrodes Program: Fiscal year 1990 annual report  

SciTech Connect

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

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

1991-08-01

420

Mobile Melt-Dilute Treatment for Russian Spent Nuclear Fuel  

SciTech Connect

Treatment of spent Russian fuel using a Melt-Dilute (MD) process is proposed to consolidate fuel assemblies into a form that is proliferation resistant and provides critically safety under storage and disposal configurations. Russian fuel elements contain a variety of fuel meat and cladding materials. The Melt-Dilute treatment process was initially developed for aluminum-based fuels so additional development is needed for several cladding and fuel meat combinations in the Russian fuel inventory (e.g. zirconium-clad, uranium-zirconium alloy fuel). A Mobile Melt-Dilute facility (MMD) is being proposed for treatment of spent fuels at reactor site storage locations in Russia; thereby, avoiding the costs of building separate treatment facilities at each site and avoiding shipment of enriched fuel assemblies over the road. The MMD facility concept is based on laboratory tests conducted at the Savannah River Technology Center (SRTC), and modular pilot-scale facilities constructed at the Savannah River Site for treatment of US spent fuel. SRTC laboratory tests have shown the feasibility of operating a Melt-Dilute treatment process with either a closed system or a filtered off-gas system. The proposed Mobile Melt-Dilute process is presented in this paper.

Peacock, H.

2002-09-17

421

Inert Anode Life in Low Temperature Reduction Process  

SciTech Connect

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

Bradford, Donald R.

2005-06-30

422

Inert failure strains of sodium aluminosilicate glass fibers  

Microsoft Academic Search

The inert failure strains (?f) of glass fibers from the compositional series 25Na2OxAl2O3(75?x)SiO2, where 0?x?32.5, were measured at 77 K using a two-point bending technique. Failure strain decreases when Al2O3 replaces SiO2, from 20.9% for x=0 to 13.7% for x=32.5. The failure strain depends on the testing speed, or faceplate velocity (Vfp) of the two-point bender. For glasses with relatively

Nathan P. Lower; Richard K. Brow; Charles R. Kurkjian

2004-01-01

423

Separation of Nuclear Fuel Surrogates from Silicon Carbide Inert Matrix  

SciTech Connect

The objective of this project has been to identify a process for separating transuranic species from silicon carbide (SiC). Silicon carbide has become one of the prime candidates for the matrix in inert matrix fuels, (IMF) being designed to reduce plutonium inventories and the long half-lives actinides through transmutation since complete reaction is not practical it become necessary to separate the non-transmuted materials from the silicon carbide matrix for ultimate reprocessing. This work reports a method for that required process.l

Dr. Ronald Baney

2008-12-15

424

Coating crystalline nuclear waste forms to improve inertness  

SciTech Connect

Crystalline waste forms of high simulated waste loading were successfully coated with layers of pyrolytic carbon and silicon carbide. Sol-gel technology was used to produce microspheres that contained simulated waste. A separate process for cesium immobilization was developed, which loads 5 wt % Cs onto zeolite particles for subsequent coating. The chemical vapor deposition process was developed for depositing thin layers of carbon and silicon carbide onto particles in a fluidized-bed coater. Pyrolytic carbon-coated particles were extremely inert in numerous leach tests. Aqueous leach test results of coated waste forms were below detection limits of such sensitive analytical techniques as atomic absorption and inductively coupled plasma atomic emission.

Stinton, D.P.; Angelini, P.; Caputo, A.J.; Lackey, W.J.

1981-01-01

425

investigation of ISI excimer pulse shaping for inert confined fusion  

NASA Astrophysics Data System (ADS)

The effort of ISI excimer pulse shaping based on gain depletion for inert confined fusion (ICF) in Heaven-I KrF laser system was introduced. The 24ns ISI pulse has been self-shortened to 10ns with a unique set-up call pulse feedback based on gain switch, which can be combined with the EFISI for the high uniformity beam profile. The shorter ISI pulses with the duration of 3~10ns have been obtained with laser quenching. The further proposal to generate a complex pulse shape for ICF based on gain depletion was discussed in this paper.

Gao, Zhixing; Lu, Ze; Zhang, Haifeng; Xiang, Yihuai; Hu, Fengming; Li, Jing; Tang, Xiuzhang

2013-05-01

426

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

SciTech Connect

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

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

2008-07-01

427

Theory of Dilute Macromolecular Solutions  

Microsoft Academic Search

The object of this paper is to lay the foundations of the Theory of Dilute Macromolecular Solutions in a unified, simplified, and yet rigorous manner. It also aims to acquaint chemists and physicists with a field of rapidly\\u000a increasing significance, in view of possible applications to biophysics (and biochemistry). The Introduction gives a brief\\u000a outline of the historical development of

A. Isihara; E. Guth

428

Asymptotic analysis of stationary adiabatic premixed flames in porous inert media  

SciTech Connect

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

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

2009-01-15

429

Asymptotic analysis of stationary adiabatic premixed flames in porous inert media  

SciTech Connect

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

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

2008-11-15

430

Dilution Models for Effluent Discharges. Third Edition.  

National Technical Information Service (NTIS)

This report describes two initial dilution plume models, RSB and UM, and model interface and manager, PLUMES, for preparing common model input and running the models. Two far-field algorithms are automatically initiated beyond the zone of initial dilution...

D. J. Baumgartner P. J. W. Roberts W. E. Frick

1994-01-01

431

Gas mixtures for spark gap closing switches  

DOEpatents

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

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

1987-02-20

432

Gas mixtures for spark gap closing switches  

DOEpatents

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

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

1988-01-01

433

Reconstruction of inert doublet scalars at the international linear collider  

NASA Astrophysics Data System (ADS)

We study collider signatures for extra scalar bosons in the inert doublet model at the international linear collider (ILC). The inert doublet model is a simple extension of the standard model by introducing an additional isospin-doublet scalar field which is odd under an unbroken Z2 symmetry. The model predicts four kinds of Z2-odd scalar bosons, and the lightest of them becomes stable and a candidate of the dark matter as long as it is electrically neutral. Taking into account the constraints from various theoretical and phenomenological conditions, we perform a simulation study for the distinctive signatures of the extra scalars over the standard-model background contributions at the ILC with the center-of-mass energy of s=250 GeV and 500 GeV. We further discuss observables for determination of the mass of the scalars. We find that the parameter regions which cannot be detected at the large hadron collider can be probed at the ILC.

Aoki, Mayumi; Kanemura, Shinya; Yokoya, Hiroshi

2013-10-01

434

Effect of inerts on layer ignition temperatures of coal dust  

SciTech Connect

An experimental study into the hot surface ignition of coal dust layers has been conducted. Two coals were examined: Prince coal from the Cape Breton Development Corporation and Pittsburgh coal from the United States Bureau of Mines. The effect of admixed inerts (dolomite and limestone) on the dust layer ignition temperature has been analyzed using a steady-state thermal explosion model. The analytical procedure used for evaluating the ignition temperature of a dust layer, heated from below and losing heat from its upper surface by convection, is an extension of the thermal explosion model of Thomas; namely, that of Thomas and Bowes. To commission the hot plate apparatus and validate the model predictions, a series of experiments were undertaken using sodium dithionite. This material is known to exhibit self-heating and there have been previous layer ignition temperature studies with which to compare results. It was demonstrated that an adequate estimate of the critical ignition temperature may be readily obtained by this analytical method. Furthermore, computed values of the critical ignition parameters for layers of coal dust admixed with inerts, accounting for changes in thermal conductivity, were in reasonable agreement with experimentally determined values.

Reddy, P.D.; Amyotte, P.R.; Pegg, M.J. [Dalhousie Univ., Halifax, Nova Scotia (Canada). Dept. of Chemical Engineering

1998-07-01

435

Amplification of Sound by Gas Phase Reactions.  

National Technical Information Service (NTIS)

A four year study of sound propagation in chemically reacting mixtures has led to experimental observation of sound amplification. Photo-initiated C12-H2-inert gas reactions provided the energy for the amplification observed. Amplification experiments wer...

H. E. Bass R. M. Detsch

1983-01-01

436

Nonequilibrium phase transition in a dilute Rydberg ensemble.  

PubMed

We demonstrate a nonequilibrium phase transition in a dilute thermal atomic gas. The phase transition, between states of low and high Rydberg occupancy, is induced by resonant dipole-dipole interactions between Rydberg atoms. The gas can be considered as dilute as the atoms are separated by distances much greater than the wavelength of the optical transitions used to excite them. In the frequency domain, we observe a mean-field shift of the Rydberg state which results in intrinsic optical bistability above a critical Rydberg number density. In the time domain, we observe critical slowing down where the recovery time to system perturbations diverges with critical exponent ?=-0.530.10. The atomic emission spectrum of the phase with high Rydberg occupancy provides evidence for a superradiant cascade. PMID:24074087

Carr, C; Ritter, R; Wade, C G; Adams, C S; Weatherill, K J

2013-09-10

437

Nonequilibrium Phase Transition in a Dilute Rydberg Ensemble  

NASA Astrophysics Data System (ADS)

We demonstrate a nonequilibrium phase transition in a dilute thermal atomic gas. The phase transition, between states of low and high Rydberg occupancy, is induced by resonant dipole-dipole interactions between Rydberg atoms. The gas can be considered as dilute as the atoms are separated by distances much greater than the wavelength of the optical transitions used to excite them. In the frequency domain, we observe a mean-field shift of the Rydberg state which results in intrinsic optical bistability above a critical Rydberg number density. In the time domain, we observe critical slowing down where the recovery time to system perturbations diverges with critical exponent ?=-0.530.10. The atomic emission spectrum of the phase with high Rydberg occupancy provides evidence for a superradiant cascade.

Carr, C.; Ritter, R.; Wade, C. G.; Adams, C. S.; Weatherill, K. J.

2013-09-01

438

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

NASA Astrophysics Data System (ADS)

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

Panahi, Allen

2009-05-01

439

Sonic black holes in dilute Bose-Einstein condensates  

Microsoft Academic Search

The sonic analog of a gravitational black hole in dilute-gas Bose-Einstein\\u000acondensates is investigated. It is shown that there exist both dynamically\\u000astable and unstable configurations which, in the hydrodynamic limit, exhibit a\\u000abehavior completely analogous to that of gravitational black holes. The\\u000adynamical instabilities involve creation of quasiparticle pairs in positive and\\u000anegative energy states. We illustrate these features

L. J. Garay; J. R. Anglin; J. I. Cirac; P. Zoller

2001-01-01

440

Bose-Einstein Condensation of Dilute Gases in Traps  

Microsoft Academic Search

The ground state of a gas of Bosons confined in an external trap potential and interacting via repulsive two-body forces has recently been shown to exhibit complete Bose-Einstein condensation in the dilute limit, yielding for the first time a rigorous proof of this phenomenon in a physically realistic setting. We give here an account of this work about the Gross-Pitaevskii

Elliott H. Lieb; Robert Seiringer

2002-01-01

441

Decomposition of dilute trichloroethylene by nonthermal plasma  

SciTech Connect

Decomposition performance of a dilute toxic organic compound, trichloroethylene (TCE), in air by using nonthermal plasma processing was studied extensively. The nonthermal plasma was generated by the high-frequency (2 kHz) or commercial-frequency (50 Hz) barrier discharge in a fused silica tube. Three types of reactors, bolt type, rod type (both are barrier-discharge type), and coil type (surface-discharge type), were tested. Analysis of byproducts, residual materials, and end products generated by the plasma process was performed by a gas chromatography mass spectrometer of gas chromatography. Most organic byproducts decrease with an increase of the electric discharge power, but only toxic phosgene increases with the increase of the discharge power. As a post process, NaOH solution was used to test effluent from the plasma reactor. The solution was found effective in phosgene absorption. Comparison between nonthermal plasma and UV irradiation for TCE decomposition was also made. In regard to the energy efficiency of the TCE decomposition, UV irradiation is found much better than discharge plasma.

Oda, Tetsuji; Takahashi, Tadashi; Tada, Keiko [Univ. of Tokyo (Japan). Dept. of Electrical Engineering

1999-03-01

442

The economics of inert anodes and wettable cathodes for aluminum reduction cells  

Microsoft Academic Search

Estimating the impact of inert-anode and wettable-cathode technologies on smelter costs must be speculative because no such\\u000a technologies have yet been commercialized. Even so, some broad conclusions can be drawn about the economic merit of inert\\u000a anodes in retrofit and greenfield smelter scenarios. Study suggests that retrofitting inert anodes to existing prebake cells\\u000a generates insufficient economic benefit to justify this

Jeff Keniry

2001-01-01

443

Processing of magnesia pyrochlore composites for inert matrix materials  

NASA Astrophysics Data System (ADS)

Inert matrix (IM) materials for nuclear fuel in light water reactors must meet several critical requirements that include high temperature stability, good irradiation behaviour, high thermal conductivity, and hot water corrosion resistance. MgO possesses all of the necessary requirements for an ideal IM candidate, except hot water corrosion resistance. A composite approach is being investigated in order to improve the corrosion resistance of MgO, while simultaneously taking advantage of the high thermal conductivity of MgO and its ability to be reprocessed in nitric acid. MgO pyrochlore composite compositions are fabricated based on neutronic property simulations for assessment as potential IM materials. The selected pyrochlore compositions are synthesized by both sol gel and solid state processing, and how composite processing affects the microstructure will be discussed. Among the multiple composite processing approaches investigated, ball milling produces the most homogeneous and consistent microstructures.

Yates, S. J.; Xu, P.; Wang, J.; Tulenko, J. S.; Nino, J. C.

2007-05-01

444

Higgs properties in a softly broken Inert Doublet Model  

NASA Astrophysics Data System (ADS)

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

Enberg, Rikard; Rathsman, Johan; Wouda, Glenn

2013-08-01

445

Production of iron and oxygen in molten K 2CO 3Na 2CO 3 by electrochemically splitting Fe 2O 3 using a cost affordable inert anode  

Microsoft Academic Search

Iron oxide was electrochemically split into iron and oxygen gas in molten Na2CO3K2CO3 at 750C using a solid iron oxide cathode and a Ni10Cu11Fe alloy inert anode. Fe2O3 was electrochemically reduced to Fe on the cathode, releasing oxygen anions into the electrolyte and which were oxidized on the anode to generate O2. The cathodic current efficiency was as high as

Huayi Yin; Diyong Tang; Hua Zhu; Yu Zhang; Dihua Wang

446

The effects of oxygen, carbon dioxide and water vapor on reprocessing silicon carbide inert matrix fuels by corrosion in molten potassium carbonate  

Microsoft Academic Search

The molten salt reaction\\/dissolution method for reprocessing silicon carbide based inert matrix fuels (IMF) is further developed in this paper through comparison of the corrosion rate in multiple gases and gas mixtures. Water vapor was firstly introduced in the SiC\\/K2CO3 corrosion system. The SiC corrosion rate in the H2O atmosphere was dramatically enhanced 34-fold compared to the rate under an

Ting Cheng; Ronald H. Baney; James Tulenko

2011-01-01

447

Dilute Acid and Autohydrolysis Pretreatment  

NASA Astrophysics Data System (ADS)

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

Yang, Bin; Wyman, Charles E.

448

Quantitative analysis of media dilution rate effects on Methanothermobacter marburgiensis grown in continuous culture on H 2 and CO 2  

Microsoft Academic Search

The characterization of hydrogenotrophic methanogens by using analytical bioprocess technology holds great potential for the development of biological gas conversion processes. Therefore, we aimed to investigate the influence of liquid dilution rate and total gassing rate on the performance of Methanothermobacter marburgiensis grown in continuous culture on H2\\/CO2.By increasing medium dilution rate M. marburgiensis biomass concentration decreased while specific methane

S. Rittmann; A. Seifert; C. Herwig

449

Dilution robustness for mean field ferromagnets  

NASA Astrophysics Data System (ADS)

In this work we compare two different random dilutions on a mean field ferromagnet: the first model is built on a Bernoulli diluted graph while the second lives on a Poisson diluted one. While it is known that the two models have, in the thermodynamic limit, the same free energy, we investigate the structural constraints that the two models must fulfill. We rigorously derive for each model the set of identities for the multi-overlap distribution, using different methods for the two dilutions: constraints in the former model are obtained by studying the consequences of the self-averaging of the internal energy density, while in the latter they are obtained by a stochastic stability technique. Finally we prove that the identities emerging in the two models are the same, showing robustness of the ferromagnetic properties of diluted graphs with respect to the details of dilution.

Barra, Adriano; Camboni, Federico; Contucci, Pierluigi

2009-03-01

450

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

Microsoft Academic Search

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

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

2005-01-01

451

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

Code of Federal Regulations, 2013 CFR

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

2013-07-01

452

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

Federal Register 2010, 2011, 2012, 2013

...Restricting the Mailing of Replica or Inert Explosive Devices AGENCY: Postal Service\\TM...restricting the mailing of replica or inert explosive devices, such as simulated grenades...dangerous but bear a realistic appearance to explosive devices, to Registered Mail\\TM\\...

2010-06-01

453

Erosion of metals by high pressure combustion gases - Inert and reactive erosion  

Microsoft Academic Search

An experimental and theoretical investigation of the erosion of various metals by high temperature, high pressure flows of combustion gases is described. The erosion process was categorized as either inert or a combination of inert and reactive erosion. Experimental results indicated the existence of two thresholds, the first represents the onset of erosion and the second the transition from purely

E. G. Plett; A. C. Alkidas; R. E. Shrader; M. Summerfield

1975-01-01

454

Inertance measurements by jet pulses in ventilated small lungs after perfluorochemical liquid (PFC) applications  

Microsoft Academic Search

Perfluorochemical liquid (PFC) liquids or aerosols are used for assisted ventilation, drug delivery, lung cancer hyperthermia and pulmonary imaging. The aim of this study was to investigate the effect of PFC liquid on the inertance (I) of the respiratory system in newborn piglets using partial liquid ventilation (PLV) with different volumes of liquid. End-inspiratory (Iin) and end-expiratory (Iex) inertance were

Gerd Schmalisch; Hans Proquitt; Mario Schmidt; Mario Rdiger; Roland R. Wauer

2005-01-01

455

Experimental study on a high frequency miniature pulse tube refrigerator with inertance tube  

NASA Astrophysics Data System (ADS)

It is generally considered that the use of an inertance tube in a high frequency pulse tube refrigerator (PTR) improves the phase shift between the pressure and the mass flow rate. In order to investigate the effects of inertance tubes on the performance of a miniature PTR, experiments on the high frequency miniature PTR with inertance tube, orifice and bypass have been carried out. Inertance tubes with various inner diameters of 0.5 mm, 1 mm, 1.5 mm, 2 mm and different lengths from 1 m to 7 m were tested. Two fine needle valves were adapted as the orifice and the bypass. The experiments were performed under a charge pressure of 2.5 MPa. The operating frequency is varied from 20 Hz to 50 Hz. Experimental results show that the inertance tube with inner diameter of 1.5 mm and length of 2 m is proper for the miniature PTR at high frequency. The benefit of using only an inertance tube is not apparent in miniature PTR. The lowest temperature achieved by the PTR with inertance tube is only 107.3 K, which is higher than the lowest temperature of 101.6 K achieved by the bypass PTR. The miniature PTR with both inertance tube and double inlet configuration has the lowest temperature of 89 K. It is also found that the bypass configuration has the function of power recovery. .

Hou, Y. K.; Ju, Y. L.; Yan, L. W.; Liang, J. T.; Zhou, Y.

2002-05-01

456

Use of a Titanium Metallocene as a Colorimetric Indicator for Learning Inert Atmosphere Techniques  

NASA Astrophysics Data System (ADS)

A method is described to aid the instruction of undergraduate and graduate students in inert atmosphere techniques. A highly oxygen-sensitive organometallic compound, a titanium metallocene, changes color form blue to yellow when exposed to dioxygen contaminant, thereby providing an easily visualized monitor for students learning to manipulate the special glassware and operations typical of inert atmosphere reactions.

Nieter Burgmayer, Sharon J.

1998-04-01

457

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

Code of Federal Regulations, 2010 CFR

...Mineral Resources 1 2009-07-01 2009-07-01 false Inerting of mine atmosphere prohibited. 75.1107-12 Section...Hydraulic Fluids on Underground Equipment § 75.1107-12 Inerting of mine atmosphere prohibited. No fire suppression...

2009-07-01

458

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

Code of Federal Regulations, 2010 CFR

...Mineral Resources 1 2010-07-01 2010-07-01 false Inerting of mine atmosphere prohibited. 75.1107-12 Section...Hydraulic Fluids on Underground Equipment § 75.1107-12 Inerting of mine atmosphere prohibited. No fire suppression...

2010-07-01

459

Band anticrossing in dilute nitrides  

SciTech Connect

Alloying III-V compounds with small amounts of nitrogen leads to dramatic reduction of the fundamental band-gap energy in the resulting dilute nitride alloys. The effect originates from an anti-crossing interaction between the extended conduction-band states and localized N states. The interaction splits the conduction band into two nonparabolic subbands. The downward shift of the lower conduction subband edge is responsible for the N-induced reduction of the fundamental band-gap energy. The changes in the conduction band structure result in significant increase in electron effective mass and decrease in the electron mobility, and lead to a large enhance of the maximum doping level in GaInNAs doped with group VI donors. In addition, a striking asymmetry in the electrical activation of group IV and group VI donors can be attributed to mutual passivation process through formation of the nearest neighbor group-IV donor nitrogen pairs.

Shan, W.; Yu, K.M.; Walukiewicz, W.; Wu, J.; Ager III, J.W.; Haller, E.E.

2003-12-23

460

Consequence of diluting modified ?-cyclodextrins in a side-chain crown ether polysiloxane and in a side-chain liquid-crystalline polysiloxane-containing crown ether as stationary phases in capillary gas chromatography  

Microsoft Academic Search

SummaryThis paper investigates the possibility of using a sidechain crown ether polysiloxane (PDB-14-C4) and a side-chain liquid-crystalline polysiloxane-containing crown ether (PSC-3) as matrices for peralkylated -CD employed as stationary phases. Three columns, coated with PSC-3 + permethylated -CD, PDB-14-C4 + permethylated -CD and PDB-14-C4 + perethylated -CD were characterized by gas chromatography. The column efficiencies, phase transitions, and selectivities were

P. Jing; R.-N. Fu; R.-J. Dai; J.-L. Ge; J.-L. Gu; Z. Huang; Y. Chen

1996-01-01

461

Evaluation of potent odorants in heated egg yolk by aroma extract dilution analysis  

Microsoft Academic Search

Egg yolk was extracted using the method of Likens-Nickerson (simultaneous distillation\\/extraction). The resulting aroma extract, which smelled characteristic of heated egg yolk was analysed by aroma extract dilution analysis and gas chromatographymass spectrometry. Of 41 odorants that were detected, 19 could be identified. Compounds with high flavour dilution factors were methional, phenyl acetaldehyde, 2-acetyl-1-pyrroline, heptanal, 1-octen-3-one and ( E, E)-2,4-decadienal.

Christoph Cerny; Rene Guntz

2004-01-01

462

Dilute Surfactant Methods for Carbonate Formations  

SciTech Connect

There are many fractured carbonate reservoirs in US (and the world) with light oil. Waterflooding is effective in fractured reservoirs, if the formation is water-wet. Many fractured carbonate reservoirs, however, are mixed-wet and recoveries with conventional methods are low (less than 10%). The process of using dilute anionic surfactants in alkaline solutions has been investigated in this work for oil recovery from fractured oil-wet carbonate reservoirs both experimentally and numerically. This process is a surfactant-aided gravity drainage where surfactant diffuses into the matrix, lowers IFT and contact angle, which decrease capillary pressure and increase oil relative permeability enabling gravity to drain the oil up. Anionic surfactants have been identified which at dilute concentration of 0.05 wt% and optimal salinity can lower the interfacial tension and change the wettability of the calcite surface to intermediate/water-wet condition as well or better than the cationic surfactant DTAB with a West Texas crude oil. The force of adhesion in AFM of oil-wet regions changes after anionic surfactant treatment to values similar to those of water-wet regions. The AFM topography images showed that the oil-wetting material was removed from the surface by the anionic surfactant treatment. Adsorption studies indicate that the extent of adsorption for anionic surfactants on calcite minerals decreases with increase in pH and with decrease in salinity. Surfactant adsorption can be minimized in the presence of Na{sub 2}CO{sub 3}. Laboratory-scale surfactant brine imbibition experiments give high oil recovery (20-42% OOIP in 50 days; up to 60% in 200 days) for initially oil-wet cores through wettability alteration and IFT reduction. Small (<10%) initial gas saturation does not affect significantly the rate of oil recovery in the imbibition process, but larger gas saturation decreases the oil recovery rate. As the core permeability decreases, the rate of oil recovery reduces, and this reduction can be scaled by the gravitational dimensionless time. Mechanistic simulation of core-scale surfactant brine imbibition matches the experimentally observed imbibition data. In-situ distributions observed through simulation indicate that surfactant diffusion (which depends on temperature and molecular weight) is the rate limiting step. Most of the oil is recovered through gravitational forces. Oil left behind at the end of this process is at its residual oil saturation. The capillary and Bond numbers are not large enough to affect the residual oil saturation. At the field-scale, 50% of the recoverable oil is produced in about 3 years if the fracture spacing is 1 m and 25% if 10 m, in the example simulated. Decreasing fracture spacing and height, increasing permeability, and increasing the extent of wettability alteration increase the rate of oil recovery from surfactant-aided gravity drainage. This dilute surfactant aided gravity-drainage process is relatively cheap. The chemical cost for a barrel of oil produced is expected to be less than $1.

Kishore K. Mohanty

2006-02-01

463

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

SciTech Connect

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

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

1990-04-01

464

DILUTE SURFACTANT METHODS FOR CARBONATE FORMATIONS  

SciTech Connect

There are many carbonate reservoirs in US (and the world) with light oil and fracture pressure below its minimum miscibility pressure (or reservoir may be naturally fractured). Many carbonate reservoirs are naturally fractured. Waterflooding is effective in fractured reservoirs, if the formation is water-wet. Many fractured carbonate reservoirs, however, are mixed-wet and recoveries with conventional methods are low (less than 10%). Thermal and miscible tertiary recovery techniques are not effective in these reservoirs. Surfactant flooding (or huff-n-puff) is the only hope, yet it was developed for sandstone reservoirs in the past. The goal of this research is to evaluate dilute (hence relatively inexpensive) surfactant methods for carbonate formations and identify conditions under which they can be effective. Laboratory imbibition tests show that imbibition rate is not very sensitive to the surfactant concentration (in the range of 0.05-0.2 wt%) and small amounts of trapped gas saturation. It is however very sensitive to oil permeability and water-oil-ratio. Less than 0.5 M Na2CO3 is needed for in situ soap generation and low adsorption; NaCl can be added to reach the necessary total salinity. The simulation result matches the laboratory imbibition experimental data. Small fracture spacing and high permeability would be needed for high rate of recovery.

Kishore K. Mohanty

2005-07-01

465

Thermo-dynamical process simulation of dilution refrigerator  

NASA Astrophysics Data System (ADS)

The design, analysis and optimization of a dilution refrigerator are carried via simulation of the thermo dynamical processes. To this end we have developed a comprehensive numerical simulation model, SIDFO (Simulation of Integrated Dilution Refrigerator for Optimization) based on enthalpy - balance considerations taking into account for several important micro-effects which are normally ignored by existing methods. The simulation has produced several unique results of the underlying phenomena occurring at various stages of the very low temperature process presented in this paper. The corresponding simulation results are compared with published experimental data of operational machines and found to comply well. The presence of 4He in the circulating gas and its consequences for the generalized cooling power is also thoroughly examined here.

Pradhan, Jedidiah; Das, Nisith Kr.; Chakraborty, Alok

2013-10-01

466

Metal ion implantation in inert polymers for strain gauge applications  

NASA Astrophysics Data System (ADS)

Metal ion implantation in inert polymers may produce ultra-thin conducting films below the polymer surface. These subsurface films are promising structures for strain gauge applications. To this purpose, polycarbonate substrates were irradiated at room temperature with low-energy metal ions (Cu+ and Ni+) and with fluences in the range between 1 1016 and 1 1017 ions/cm2, in order to promote the precipitation of dispersed metal nanoparticles or the formation of a continuous thin film. The nanoparticle morphology and the microstructural properties of polymer nanocomposites were investigated by glancing-incidence X-ray diffraction and transmission electron microscopy (TEM) measurements. At lower fluences (<5 1016 ions/cm2) a spontaneous precipitation of spherical-shaped metal nanoparticles occurred below the polymer top-surface (50 nm), whereas at higher fluences the aggregation of metal nanoparticles produced the formation of a continuous polycrystalline nanofilm. Furthermore, a characteristic surface plasmon resonance peak was observed for nanocomposites produced at lower ion fluences, due to the presence of Cu nanoparticles. A reduced electrical resistance of the near-surface metal-polymer nanocomposite was measured. The variation of electrical conductivity as a function of the applied surface load was measured: we found a linear relationship and a very small hysteresis.

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

2010-10-01

467

Porous HMX initiation studies -- Sugar as an inert simulant  

SciTech Connect

For several years the authors have been using magnetic particle velocity gauges to study the shock loading of porous HMX (65 and 73% TMD) of different particle sizes to determine their compaction and initiation characteristics. Because it has been difficult to separate the effects of compaction and reaction, an inert simulant was needed with properties similar to HMX. Sugar was selected as the simulant for several reasons: (1) the particle size distribution of C and H granulated sugar is similar to the coarse HMX the authors have been using (120 {micro}m average size), (2) the particle size of C and H confectioners (powdered) sugar is similar to the fine HMX in the studies (10 {micro}m average size), (3) it is an organic material, and (4) sugar was readily available. Because the densities of HMX and sugar are somewhat different, the authors chose to do the experiments on sugar compacts at 65 and 73% TMD. As expected, no reaction was observed in the sugar experiments. Compaction wave profiles were similar to those measured earlier for the HMX, i.e., the compaction waves in the coarse sugar were quite disperse while those in the fine sugar were much sharper. This indicates that the compaction wave profiles are controlled by particle size and not reaction. Also, the coarse sugar gauge signals exhibited a great deal of noise, thought to the be result of fracto-emission.

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

1997-11-01

468

DNP System Output Volume Reduction Using Inert Fluids  

PubMed Central

Purpose To present a method for significantly increasing the concentration of a hyperpolarized compound produced by a commercial DNP polarizer, enabling the polarization process to be more suitable for pre-clinical applications. Materials and Methods Using a HyperSense DNP polarizer, we have investigated the combined use of perfluorocarbon and water to warm and dissolve the hyperpolarized material from the polarization temperature of 1.4 K to produce material at temperatures suitable for injection. Results By replacing 75% of the water in the dissolution volume with a chemically and biologically inert liquid that is immiscible with water, the injection volume can be reduced fourfold Rapid separation of the water and perfluorocarbon mixture enables the aqueous layer containing polarized material to be easily and rapidly collected. Conclusion The approach provides a significantly increased concentration of compound in a volume for injection that is more appropriate for small animal studies. This is demonstrated for 13C labeled pyruvic acid and 13C labeled succinate, but may be applied to the majority of nuclei and compounds hyperpolarized by the DNP method.

Peterson, Eric T; Gordon, Jeremy W; Erickson, Matthew G; Fain, Sean B; Rowland, Ian J

2011-01-01

469

Investigation of materials for inert electrodes in aluminum electrodeposition cells  

SciTech Connect

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

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

1987-09-14

470

The Shock Response and Microstructural Determination of an Inert Simulant  

NASA Astrophysics Data System (ADS)

The resolution of details of the microstructure in a polymer matrix composite has important applications in addressing safety issues in energetic materials. The generation of three-dimensional microstructure, using a non-invasive method of high resolution will advance knowledge in a range of fields. A series of inert composites have been studied with microstructure analogous to that of plastic bonded explosives (PBXs). The experimental aims of this study lay in several areas. Firstly, adequately defining the bulk morphology. Secondly in determining the geometry of defects that might lead to sites for accidental ignition within the material. Finally in demonstrating a direct linkage into the finite element prediction of mechanical response. The study included investigation of materials selected to firstly test the resolution limits of the X-ray microtomography equipment, but also since a parallel series of shock experiments (with associated modelling) was conducted. This work is the first step in providing a coordinated capability to understand accidental ignition within insensitive high explosives (IHEs).

MacDonald, S. A.; Millett, J. C. F.

2005-07-01

471

A method for the determination of amitriptyline and its metabolites nortriptyline, 10-hydroxyamitriptyline, and 10-hydroxynortriptyline in human plasma using stable isotope dilution and gas chromatography-chemical ionization mass spectrometry (GC-CIMS).  

PubMed

A gas chromatography--mass spectrometry (GC-MS) method has been developed to measure amitriptyline and its metabolites nortriptyline, 10-hydroxyamitriptyline, and 10-hydroxynortriptyline in human plasma. Deuterated analogs of each compound were synthesized as internal standards. Isobutane was used as both gas chromatography (GC) carrier gas and chemical ionization (CI) reagent gas. In order to obtain compounds with satisfactory GC and mass spectrometry (MS) properties, the two alcohol metabolites were dehydrated without loss of label during sample preparation. Selective ion monitoring of the MH+ ions of the protio- and deuterio- compounds gave ion ratios which were converted to plasma concentrations using standard curves. For amitriptyline and nortriptyline, which are assayed using multiple deuterated analogs as internal standards, the curves are straight lines. For 10-hydroxyamitriptyline and 10-hydroxynortriptyline, which are assayed using monodeuterated analogs as internal standards, the curves are nonlinear and are analyzed using an iterative computer procedure. Assay sensitivity is 0.5 ng/ml for amitriptyline, nortriptyline, and 10-hydroxyamitriptyline and 1 ng/ml for 10-hydroxynortriptyline. Assay precision and accuracy in terms of percent error are both less than 5%. Following oral administration of a single 75-mg dose of amitriptyline to two subjects, the mean plasma levels of amitriptyline, nortriptyline, 10-hydroxyamitriptyline, conjugated 10-hydroxyamitriptyline, 10-hydroxynortriptyline, and conjugated 10-hydroxynortriptyline were 36, 8, 10, 66, 16, and 46 ng/ml, respectively, at 2 hr after dosing and 3, 4, 0.5, 1, 6, and 17 ng/ml, respectively, at 72 hr after dosing. Analyses of plasma samples from 12 subjects who had been receiving 50 mg amitriptyline therapy three times a day for an average +/- SD of 32 +/- 5 days gave a mean concentration of 81 +/- 40 ng/ml for amitriptyline, 71 +/- 57 ng/ml for nortriptyline, 12 +/- 5 ng/ml for 10-hydroxyamitriptyline, 91 +/- 30 ng/ml for conjugated 10-hydroxyamitriptyline, 82 +/- 27 ng/ml for 10-hydroxynortriptyline, and 176 +/- 64 ng/ml for conjugated 10-hydroxynortriptyline. PMID:376209

Garland, W A; Muccino, R R; Min, B H; Cupano, J; Fann, W E

1979-06-01

472

Measurements of mass-fraction activity coefficient at infinite dilution of aliphatic and aromatic hydrocarbons, thiophene, alcohols, water, ethers, and ketones in hyperbranched polymer, Boltorn H2004, using inverse gas chromatography  

Microsoft Academic Search

Thermodynamic properties of the hyperbranched polymer, Boltorn H2004 (B-H2004), were investigated by inverse gas chromatography with 42 different solvents: n-alkanes (C5C10), cycloalkanes (C5C8), alkenes (C5C8), alkynes (C5C8), aromatic hydrocarbons (benzene, toluene, ethylbenzene, o-, m-, p-xylene, thiophene), alcohols (C1C5), water, ethers (tetrahydrofuran (THF), methyl-tert-butylether (MTBE), diethyl-, di-n-propyl-, di-n-butyl ether), and ketones (acetone, 2-pentanone, 3-pentanone, 2-hexanone, 3-hexanone, cyclopentanone) at the temperatures from

Urszula Doma?ska; Zuzanna ?o?ek-Tryznowska

2010-01-01

473

40 CFR 1065.240 - Dilution air and diluted exhaust flow meters.  

Code of Federal Regulations, 2013 CFR

...meter to determine instantaneous diluted exhaust flow rates or total diluted exhaust flow over a test interval. You may use the difference...and a dilution air meter to calculate raw exhaust flow rates or total raw exhaust flow over a test...

2013-07-01

474

Kinetic model of ionization waves in a positive column at intermediate pressures in inert gases  

NASA Astrophysics Data System (ADS)

A kinetic model of ionization waves in the inert gas discharge is constructed, which is based on the simultaneous solution of the kinetic equation for electrons and the continuity equations for ions and excited atoms. The model corresponds to a range of intermediate pressures and small currents, when elastic collisions dominate in the electron energy balance and electron-electron collisions are negligibly small. A linear theory of ionization waves is constructed, growth rates and frequencies of wave disturbances able to propagate in plasma are found. It is shown that there is an upper bound to the existence of striations by pressure, as well as the lower bound by current. The self-consistent solution of the source system of equations is obtained, which describes a nonlinear wave. The profile of electric field and the electron distribution function in this field are calculated. The results of calculations are compared with the experimental data. The wavelengths obtained are essentially larger than the electron energy relaxation length. Such waves cannot be described within the limits of fluid models.

Golubovskii, Yu. B.; Maiorov, V. A.; Nekutchaev, V. O.; Behnke, J.; Behnke, J. F.

2001-03-01

475

Bayesian Analysis of Serial Dilution Assays  

Microsoft Academic Search

Summary. In a serial dilution assay, the concentration of a compound is estimated by combining mea- surements of several different dilutions of an unknown sample.The relation between concentration and measurement is nonlinear and heteroscedastic, and so it is not appropriate to weight these measurements equally.In the standard existing approach for analysis of these data, a large proportion of the measurements

Andrew Gelman; Ginger L. Chew; Michael Shnaidman

2004-01-01

476

DAVINCI a Dilute Aperture Coronagraph  

NASA Astrophysics Data System (ADS)

The motivation for DAVINCI was originally to make use of the technology developed for space interferometers like SIM to build a coronagraph from four 1.1m telescopes that was dramatically lower in cost than a 4 5m filled aperture offaxis coronagraph. Our initial studies through team X have shown this cost savings to be real. But a more careful analysis showed that DAVINCI would have an inner working angle of 35mas a factor of 2 smaller than a 2 lambda/D 4 meter coronagraph or 70m external occulter, resulting in a 10X increase in the number of potential Earth-Clone targets. DAVINCI uses a nulling interferometer as a coronagraph, a nulling interferometer is one the few coronagraph architectures that are compatible with segmented and dilute aperture telescopes. Combined with a post coronagraph wavefront sensor several ultra-demanding tolerances of conventional coronagraphs can be relaxed by factors of 100. The post coronagraph wavefront sensor is also much less affected by local and exozodi background than wavefront sensors that use the science camera as the wavefront sensor. The post coronagraph interferometer is also used on ground based extreme AO coronagraphs, GPI, and P1640.

Shao, Michael

2009-01-01

477

Control of degradation of spent LWR (light-water reactor) fuel during dry storage in an inert atmosphere  

SciTech Connect

Dry storage of Zircaloy-clad spent fuel in inert gas (referred to as inerted dry storage or IDS) is being developed as an alternative to water pool storage of spent fuel. The objectives of the activities described in this report are to identify potential Zircaloy degradation mechanisms and evaluate their applicability to cladding breach during IDS, develop models of the dominant Zircaloy degradation mechanisms, and recommend cladding temperature limits during IDS to control Zircaloy degradation. The principal potential Zircaloy cladding breach mechanisms during IDS have been identified as creep rupture, stress corrosion cracking (SCC), and delayed hydride cracking (DHC). Creep rupture is concluded to be the primary cladding breach mechanism during IDS. Deformation and fracture maps based on creep rupture were developed for Zircaloy. These maps were then used as the basis for developing spent fuel cladding temperature limits that would prevent cladding breach during a 40-year IDS period. The probability of cladding breach for spent fuel stored at the temperature limit is less than 0.5% per spent fuel rod. 52 refs., 7 figs., 1 tab.

Cunningham, M.E.; Simonen, E.P.; Allemann, R.T.; Levy, I.S.; Hazelton, R.F.

1987-10-01

478

Differential isospin-fractionation in dilute asymmetric nuclear matter  

SciTech Connect

The differential isospin-fractionation (IsoF) during the liquid-gas phase transition in dilute asymmetric nuclear matter is studied as a function of nucleon momentum. Within a self-consistent thermal model it is shown that the neutron/proton ratio of the gas phase becomes smaller than that of the liquid phase for energetic nucleons, although the gas phase is overall more neutron-rich. Clear indications of the differential IsoF consistent with the thermal model predictions are demonstrated within a transport model for heavy-ion reactions. Future comparisons with experimental data will allow us to extract critical information about the momentum dependence of the isovector strong interaction.

Li Baoan [Department of Physics, Texas A and M University-Commerce, Commerce, Texas 75429-3011 (United States); Chen Liewen [Department of Physics, Texas A and M University-Commerce, Commerce, Texas 75429-3011 (United States); Institute of Theoretical Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Center of Theoretical Nuclear Physics, National Laboratory of Heavy-Ion Accelerator, Lanzhou 730000 (China); Ma Hongru; Xu Jun [Institute of Theoretical Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Yong Gaochan [Department of Physics, Texas A and M University-Commerce, Commerce, Texas 75429-3011 (United States); Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

2007-11-15

479

Effects of Hypergravity and Anti-G-Suit Pressurization on Intrapulmonary Gas Mixing and Gas Trapping.  

National Technical Information Service (NTIS)

The purpose of this study was to assess the effects of hypergravity and AGS pressurization on the resting lung volume, on the efficiency of intrapulmonary gas mixing and on gas trapping in the lungs, using an inert gas washout method. The authors report t...

M. Groenkvist E. Bergsten O. Eiken R. Koelegard B. Lindborg P. M. Gustaffson

2000-01-01

480

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

Microsoft Academic Search

An inert anode for the electrolytic production of metals such as aluminum is disclosed. The inert anode includes a ceramic oxide material preferably made from NiO, Fe.sub.2 O.sub.3 and ZnO. The inert anode composition may comprise the following mole fractions of NiO, Fe.sub.2 O.sub.3 and ZnO: 0.2 to 0.99 NiO; 0.0001 to 0.8 Fe.sub.2 O.sub.3 ; and 0.0001 to 0.3

Siba P. Ray; Weirauch Jr. Douglas A; Xinghua Liu

2002-01-01