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1

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

Microsoft Academic Search

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

Mamoru Okumoto; Zhenzhou Su; Shinji Katsura; Akira Mizuno

1997-01-01

2

Purification of Inert Gas  

Microsoft Academic Search

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

Keiji NAITO; Toshihide TSUJI; Tsuneo MATSUI; Katsumi UNE

1974-01-01

3

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

Microsoft Academic Search

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

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

1981-01-01

4

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

NASA Astrophysics Data System (ADS)

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

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

1981-03-01

5

Inert Gas Dilution Effect on the Flammability Limits of Hydrocarbon Mixtures  

E-print Network

previous one from U.S. BMs???????....69 5.3 Ethane flammability properties with dilution of nitrogen (25 ?C and 1 atm)??????????????????????..????.. 70 5.4 Propane flammability properties with dilution of nitrogen (25 ?C and 1 atm...)???????????????????????..???.. 72 5.8 Flammability properties of methane and propane at different molar radios (20 %/80%, 40%/60%, 60%/40%, and 80%/20%) with dilution of nitrogen (25 ?C and 1 atm)?..????.?..?????????73 5.9 Flammability properties of ethane and propane...

Zhao, Fuman

2012-02-14

6

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

Microsoft Academic Search

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

Jayshree Seth; S. V. Babu

1993-01-01

7

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

Code of Federal Regulations, 2013 CFR

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

2013-07-01

8

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

Code of Federal Regulations, 2010 CFR

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

2010-07-01

9

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

Code of Federal Regulations, 2012 CFR

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

2012-07-01

10

Inert gas thrusters  

NASA Technical Reports Server (NTRS)

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

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

1979-01-01

11

Inert gas thrusters  

NASA Technical Reports Server (NTRS)

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

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

1980-01-01

12

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

Microsoft Academic Search

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

Mamoru Okumoto; Zhenzhou Su; Shinji Katsura; Akira Mizuno

1999-01-01

13

46 CFR 154.906 - Inert gas generators.  

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

2014-10-01

14

46 CFR 154.906 - Inert gas generators.  

Code of Federal Regulations, 2013 CFR

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

2013-10-01

15

46 CFR 154.906 - Inert gas generators.  

Code of Federal Regulations, 2011 CFR

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

2011-10-01

16

46 CFR 154.906 - Inert gas generators.  

Code of Federal Regulations, 2012 CFR

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

2012-10-01

17

46 CFR 154.906 - Inert gas generators.  

Code of Federal Regulations, 2010 CFR

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

2010-10-01

18

Mechanisms of inert gas narcosis  

NASA Technical Reports Server (NTRS)

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

1973-01-01

19

46 CFR 154.904 - Inert gas system: Controls.  

Code of Federal Regulations, 2010 CFR

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

2010-10-01

20

46 CFR 154.908 - Inert gas generator: Location.  

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

2014-10-01

21

46 CFR 154.908 - Inert gas generator: Location.  

Code of Federal Regulations, 2013 CFR

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

2013-10-01

22

46 CFR 154.908 - Inert gas generator: Location.  

Code of Federal Regulations, 2010 CFR

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

2010-10-01

23

46 CFR 154.908 - Inert gas generator: Location.  

Code of Federal Regulations, 2012 CFR

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

2012-10-01

24

46 CFR 154.908 - Inert gas generator: Location.  

Code of Federal Regulations, 2011 CFR

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

2011-10-01

25

Inert gas ups viscous oil production  

Microsoft Academic Search

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

Davison

1965-01-01

26

Barge brings inert gas where needed  

Microsoft Academic Search

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

Bleakley

1968-01-01

27

46 CFR 154.903 - Inert gas systems: General.  

Code of Federal Regulations, 2010 CFR

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

2010-10-01

28

Positron-inert gas differential elastic scattering  

NASA Technical Reports Server (NTRS)

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

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

1990-01-01

29

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

Code of Federal Regulations, 2011 CFR

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

2011-07-01

30

Refractory metals welded or brazed with tungsten inert gas equipment  

NASA Technical Reports Server (NTRS)

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

Wisner, J. P.

1965-01-01

31

Metal inert gas welding system for use in vacuum  

Microsoft Academic Search

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

Charles D. Stocks

1994-01-01

32

Metal inert gas welding system for use in vacuum  

Microsoft Academic Search

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

Charles D. Stocks

1993-01-01

33

46 CFR 153.501 - Requirement for dry inert gas.  

Code of Federal Regulations, 2010 CFR

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

2010-10-01

34

46 CFR 153.500 - Inert gas systems.  

Code of Federal Regulations, 2010 CFR

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

2010-10-01

35

Inert-Gas Diffuser For Plasma Or Arc Welding  

NASA Technical Reports Server (NTRS)

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

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

1994-01-01

36

Metal inert gas welding system for use in vacuum  

NASA Astrophysics Data System (ADS)

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

Stocks, Charles D.

1994-08-01

37

Metal inert gas welding system for use in vacuum  

NASA Astrophysics Data System (ADS)

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

Stocks, Charles D.

1993-09-01

38

Repulsive Interactions and Molecular Rotation in Inert-Gas Lattices  

Microsoft Academic Search

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

R. L. Armstrong

1966-01-01

39

Lattice Dynamics of Inert Gas Monolayers  

NASA Astrophysics Data System (ADS)

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

Hakim, Toufic Maurice

40

46 CFR 153.462 - Static discharges from inert gas systems.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Static discharges from inert gas systems. ...Or Combustible Cargoes § 153.462 Static discharges from inert gas systems. ...flammable or combustible cargo must not create static arcing as the inert gas is injected...

2013-10-01

41

46 CFR 153.462 - Static discharges from inert gas systems.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Static discharges from inert gas systems. ...Or Combustible Cargoes § 153.462 Static discharges from inert gas systems. ...flammable or combustible cargo must not create static arcing as the inert gas is injected...

2012-10-01

42

46 CFR 153.462 - Static discharges from inert gas systems.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Static discharges from inert gas systems. ...Or Combustible Cargoes § 153.462 Static discharges from inert gas systems. ...flammable or combustible cargo must not create static arcing as the inert gas is injected...

2011-10-01

43

46 CFR 153.462 - Static discharges from inert gas systems.  

Code of Federal Regulations, 2010 CFR

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

2010-10-01

44

Elastic electron scattering from inert-gas atoms  

SciTech Connect

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

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

2005-09-01

45

Development of advanced inert-gas ion thrusters  

NASA Technical Reports Server (NTRS)

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

Poeschel, R. L.

1983-01-01

46

Relating indices of inert gas washout to localised bronchoconstriction  

PubMed Central

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

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

2012-01-01

47

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

Microsoft Academic Search

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

R. Saleh; L. Munisa; W. Beyer

2004-01-01

48

Visual/vestibular effects of inert gas narcosis.  

PubMed

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

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

1993-08-01

49

Hepatic blood flow measurement with inert gas clearance.  

PubMed

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

Mathie, R T

1986-07-01

50

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

PubMed Central

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

Anderson, Joseph C.; Hlastala, Michael P.

2011-01-01

51

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

52

Numerical Simulation on Inert Gas Injection Applied to Sealed Fire Area  

Microsoft Academic Search

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

Jiuling Zhang; Xinquan Zhou; Wu Gong; Yuehong Wang

53

Operation of the J-series thruster using inert gas  

NASA Technical Reports Server (NTRS)

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

Rawlin, V. K.

1982-01-01

54

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

55

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

Microsoft Academic Search

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

Mikio ENOEDA; Takeshi HIGASHIJIMA; Masabumi NISHIKAWA; Nobuo MITSUISHI

1986-01-01

56

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

SciTech Connect

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

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

1998-04-01

57

Role of Carbon Dioxide in Inert Gas Narcosis.  

National Technical Information Service (NTIS)

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

H. S. Weiss

1977-01-01

58

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

NASA Technical Reports Server (NTRS)

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

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

2007-01-01

59

Gas dilution system results and application to acid rain utilities  

SciTech Connect

In 1997, the United States EPA will remove restrictions preventing acid rain utilities from using gas dilution systems for calibration or linearity studies for continuous emissions monitoring, Test Method 205 in 40CFR51 requires that a gas dilution system must produce calibration gases whose measured values are within {+-}2% of predicted values. This paper presents the evaluation of the Environics/CalMat 2020 Dilution System for use in calibration studies. Internal studies show that concentrations generated by this unit are within {+-}0.5% of predicted values. Studies are being conducted by several acid rain utilities to evaluate the Environics/CalMat system using single minor component calibration standards. In addition, an internally generated study is being performed to demonstrate the system`s accuracy using a multi-component gas mixture. Data from these tests will be presented in the final version of the paper.

Jolley-Souders, K.; Geib, R. [Matheson Gas Products, Montgomeryville, PA (United States); Dunn, C. [Environics, Inc., Tolland, CT (United States)

1997-12-31

60

Evaluation of two gas-dilution methods for instrument calibration  

NASA Technical Reports Server (NTRS)

Two gas dilution methods were evaluated for use in the calibration of analytical instruments used in air pollution studies. A dual isotope fluorescence carbon monoxide analyzer was used as the transfer standard. The methods are not new but some modifications are described. The rotary injection gas dilution method was found to be more accurate than the closed loop method. Results by the two methods differed by 5 percent. This could not be accounted for by the random errors in the measurements. The methods avoid the problems associated with pressurized cylinders. Both methods have merit and have found a place in instrument calibration work.

Evans, A., Jr.

1977-01-01

61

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

NASA Technical Reports Server (NTRS)

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

1974-01-01

62

Predictability of PaO2 in different inert gas-oxygen environments  

Microsoft Academic Search

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

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

1972-01-01

63

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

Microsoft Academic Search

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

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

1990-01-01

64

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

65

Prevention of defluidization by gas dilution for reactions involving gas–volume reduction  

Microsoft Academic Search

In industrial fluidized bed processes, the system often involved a change in volumetric flow. Defluidization occurs when reactions involving a decrease in gas volume are carried out in a fluidized catalyst bed. This is due to decrease in gas velocity below the minimum fluidization velocity in the emulsion phase. One method to improve fluidization quality is to supply an inert

Takami Kai; Mitsunobu Furukawa; Tsutomu Nakazato; Mitsuyuki Nakajima

2011-01-01

66

Quasiclassical molecular dynamics for the dilute Fermi gas at unitarity  

NASA Astrophysics Data System (ADS)

We study the dilute Fermi gas at unitarity using molecular dynamics with an effective quantum potential constructed to reproduce the quantum two-body density matrix at unitarity. Results for the equation of state, the pair-correlation function, and the shear viscosity are presented. These quantities are well understood in the dilute, high-temperature limit. Using molecular dynamics we determine higher-order corrections in the diluteness parameter n?3, where n is the density and ? is the thermal de Broglie wavelength. In the case of the contact density, which parameterizes the short distance behavior of the correlation function, we find that the results of molecular dynamics interpolate between the truncated second- and third-order virial expansion and are in excellent agreement with existing T-matrix calculations. For the shear viscosity we reproduce the expected scaling behavior at high temperature, ?˜1/?3, and we determine the leading density-dependent correction to this result.

Dusling, K.; Schäfer, T.

2012-12-01

67

Modeling syngas-fired gas turbine engines with two dilutants  

NASA Astrophysics Data System (ADS)

Prior gas turbine engine modeling work at the University of Wyoming studied cycle performance and turbine design with air and CO2-diluted GTE cycles fired with methane and syngas fuels. Two of the cycles examined were unconventional and innovative. The work presented herein reexamines prior results and expands the modeling by including the impacts of turbine cooling and CO2 sequestration on GTE cycle performance. The simple, conventional regeneration and two alternative regeneration cycle configurations were examined. In contrast to air dilution, CO2 -diluted cycle efficiencies increased by approximately 1.0 percentage point for the three regeneration configurations examined, while the efficiency of the CO2-diluted simple cycle decreased by approximately 5.0 percentage points. For CO2-diluted cycles with a closed-exhaust recycling path, an optimum CO2-recycle pressure was determined for each configuration that was significantly lower than atmospheric pressure. Un-cooled alternative regeneration configurations with CO2 recycling achieved efficiencies near 50%, which was approximately 3.0 percentage points higher than the conventional regeneration cycle and simple cycle configurations that utilized CO2 recycling. Accounting for cooling of the first two turbine stages resulted in a 2--3 percentage point reduction in un-cooled efficiency, with air dilution corresponding to the upper extreme. Additionally, when the work required to sequester CO2 was accounted for, cooled cycle efficiency decreased by 4--6 percentage points, and was more negatively impacted when syngas fuels were used. Finally, turbine design models showed that turbine blades are shorter with CO2 dilution, resulting in fewer design restrictions.

Hawk, Mitchell E.

68

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

Microsoft Academic Search

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

Rosari Saleh; Lusitra Munisa; Wolfhard Beyer

2006-01-01

69

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

E-print Network

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

DeVore, Robin Kent

2012-06-07

70

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

SciTech Connect

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

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

2010-11-07

71

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

NASA Technical Reports Server (NTRS)

This report compares results obtained for the determination of nitrogen in a selected group of niobium-base alloys by the inert-gas-fusion and the Kjeldahl procedures. In the inert-gas-fusion procedure the sample is heated to approximately 2700 C in a helium atmosphere in a single-use graphite crucible. A platinum flux is used to facilitate melting of the sample. The Kjeldahl method consisted of a rapid decomposition with a mixture of hydrofluoric acid, phosphoric acid, and potassium chromate; distillation in the presence of sodium hydroxide; and highly sensitive spectrophotometry with nitroprusside-catalyzed indophenol. In the 30- to 80-ppm range, the relative standard deviation was 5 to 7 percent for the inert-gas-fusion procedure and 2 to 8 percent for the Kjeldahl procedure. The agreement of the nitrogen results obtained by the two techniques is considered satisfactory.

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

1974-01-01

72

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

PubMed

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

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

2012-04-01

73

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

74

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

PubMed Central

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

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

2014-01-01

75

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

PubMed

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

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

2015-01-01

76

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

Microsoft Academic Search

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

S. C Juang; Y. S Tarng

2002-01-01

77

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

Microsoft Academic Search

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

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

2009-01-01

78

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

Microsoft Academic Search

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

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

2008-01-01

79

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

80

Deposition of Size-Selected Cu Nanoparticles by Inert Gas Condensation  

PubMed Central

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

2010-01-01

81

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

SciTech Connect

The treatment of spent fuel produced in nuclear power generation is one of the most important issues to both the nuclear community and the general public. One of the viable options to long-term geological disposal of spent fuel is to extract plutonium, minor actinides (MA), and potentially long-lived fission products from the spent fuel and transmute them into short-lived or stable radionuclides in currently operating light-water reactors (LWR), thus reducing the radiological toxicity of the nuclear waste stream. One of the challenges is to demonstrate that the burnup-dependent characteristic differences between Reactor-Grade Mixed Oxide (RG-MOX) fuel and RG-MOX fuel with MA Np-237 and Am 241 are minimal, particularly, the inert gas generation rate, such that the commercial MOX fuel experience base is applicable. Under the Advanced Fuel Cycle Initiative (AFCI), developmental fuel specimens in experimental assembly LWR-2 are being tested in the northwest (NW) I-24 irradiation position of the Advanced Test Reactor (ATR). The experiment uses MOX fuel test hardware, and contains capsules with MOX fuel consisting of mixed oxide manufactured fuel using reactor grade plutonium (RG-Pu) and mixed oxide manufactured fuel using RG-Pu with added Np/Am. This study will compare the fuel neutronics depletion characteristics of Case-1 RG-MOX and Case-2 RG-MOX with Np/Am.

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

2006-06-01

82

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

83

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

PubMed

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

Sato, K; Nakamura, K; Sato, S

1985-09-01

84

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

PubMed

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

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

2003-07-01

85

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

NASA Astrophysics Data System (ADS)

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

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

2005-01-01

86

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

SciTech Connect

This paper describes an updated Orbital design of a radioisotope Stirling power system and its predicted performance at the beginning and end of a six-year mission to the Jovian moon Europa. The design is based on General Purpose Heat Source (GPHS) modules identical to those previously developed and safety-qualified by the Department of Energy (DOE) which were successfully launched to Jupiter and Saturn by the Jet Propulsion Laboratory (JPL). In each generator, the heat produced by the decay of the Pu-238 isotope is converted to electric power by two free-piston Stirling engines and linear alternators developed by Stirling Technology Company (STC), and their rejected waste heat is transported to radiators by heat pipes. The principal difference between the proposed system design and previous Orbital designs (Or et al. 2000) is the thermal insulation between the heat source and the generator's housing. Previous designs had employed multifoil insulation, whereas the design described here employs Min-K-1800 thermal insulation. Such insulation had been successfully used by Teledyne and GE in earlier RTGs (Radioisotope Thermoelectric Generators). Although Min-K is a much poorer insulator than multifoil in vacuum and requires a substantially greater thickness for equivalent performance, it offers compensating advantages. Specifically it makes it possible to adjust the generator's BOM temperatures by filling its interior volume with inert cover gas. This makes it possible to meet the generator's BOM and EOM performance goals without exceeding its allowable temperature at the beginning of the mission.

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

2001-01-01

87

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

NASA Astrophysics Data System (ADS)

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

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

2012-03-01

88

Soret and Dilution Effects on Premixed Flames  

Microsoft Academic Search

The structure of a wrinkled premixed flame is analysed theoretically. By assuming the reactive mixture diluted in an inert gas and a weak cross-diffusion coupling between the heat and mass fluxes, the effect of the change by the reaction of the physical gas properties (thermal conductivity, specific heat, number of molecules) and Soret and Dufour diffusions have been investigated in

PEDRO GARCÍA-YBARRA; COLETTE NICOLI; PAUL CLAVIN

1984-01-01

89

Three stage gas dilution system for calibration of air quality instrumentation  

NASA Technical Reports Server (NTRS)

Tests were conducted on a three stage gas dilution system to evaluate the performance of the system for preparation of gas mixtures in the range of concentrations from 1 to 200 ppm. The test gas used in the evaluation was carbon monoxide. Mixtures of carbon monoxide and air were prepared in the gas dilution system and analyzed on stream with a commercially available infrared CO detector. Results showed the gas dilution system to be accurate to within 5, 3, and 2 percent in the respective ranges of 1-20 ppm, 20-50 ppm, and 50-200 ppm.

Gregory, G. L.; Emerson, B. R.; Hudgins, C. H.

1974-01-01

90

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

Microsoft Academic Search

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

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

91

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

Microsoft Academic Search

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

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

2006-01-01

92

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

SciTech Connect

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

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

2013-11-21

93

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

PubMed Central

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

2012-01-01

94

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

95

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

Microsoft Academic Search

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

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

96

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

NASA Technical Reports Server (NTRS)

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

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

2001-01-01

97

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

98

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

99

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

100

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

101

Nitrogen dilution effect on the flammability limits for hydrocarbons  

Microsoft Academic Search

Theoretical models to predict the upper\\/lower flammability limits of hydrocarbons diluted with inert nitrogen gas are proposed in this study. It is found that there are linear relations between the reciprocal of the upper\\/lower flammability limits and the reciprocal of the molar fraction of hydrocarbon in the hydrocarbon\\/inert nitrogen mixture. Such linearity is examined by experimental data reported in the

Chan-Cheng Chen; Tzu-Chi Wang; Horng-Jang Liaw; Hui-Chu Chen

2009-01-01

102

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

SciTech Connect

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

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

2009-09-15

103

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

SciTech Connect

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

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

1996-12-31

104

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

NASA Technical Reports Server (NTRS)

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

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

2001-01-01

105

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

SciTech Connect

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

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

2011-01-17

106

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

E-print Network

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

Elperin, Tov

107

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

SciTech Connect

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

Mielke, J.E.

1996-10-09

108

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

109

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

110

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

Microsoft Academic Search

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

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

2009-01-01

111

Dilute turbulent gas-solid flow in risers with particle-particle interactions  

Microsoft Academic Search

Dispersed gas-solid turbulent flows are encountered in a wide variety of chemical processes. Such processes include coal injection into entrained-flow gasifiers, pneumatic conveying of solids in transport lines, and high velocity fluidization as found in circulating fluidized beds (CFBs). Earlier work of Sinclair and Jackson that treats the laminar flow of gas-solid suspensions is extended to model dilute turbulent flow.

Eduardo J. Bolio; Jules A. Yasuna; Jennifer L. Sinclair

1995-01-01

112

EFFECT OF VENTILATION AND PERFUSION IMBALANCE ON INERT GAS REBREATHING VARIABLES  

EPA Science Inventory

The effects of ventilation-to-perfusion (Va/Qc) maldistribution within the lungs on measured multiple gas rebreathing variables were studied in 14 dogs. The rebreathing method (using He, C18C, and C2H2) allows for measurements of pulmonary capillary blood flow (Qc), diffusing cap...

113

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

114

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

115

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

NASA Astrophysics Data System (ADS)

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

Siefart, E.

116

Infinite dilution activity coefficients of apple juice aroma compounds  

Microsoft Academic Search

An apparatus based on the inert gas stripping method was assembled for measuring infinite dilution activity coefficients, ??, of 15 apple juice aroma compounds in aqueous solutions. Values were estimated using the UNIFAC model and compared with experimental results; differences ranged from ?80 to 118% with an average of 48% for the absolute values of the differences. Values predicted with

Martin F. Sancho; M. A. Rao; D. L. Downing

1997-01-01

117

Inert gas dilution and ion bombardment effects in room temperature (35 C) plasma deposition of a-Si:H  

SciTech Connect

Plasma enhanced chemical vapor deposition (PECVD) of a-Si:H with silane or silane and hydrogen at temperatures lower than 200 C commonly results in films with significant dihydride bonding and a high defect density. In this paper, the authors demonstrate the formation of monohydride dominant a-Si:H films using rf parallel plate PECVD at 35 C at deposition rates greater than 100 {angstrom}/min. In the as-deposited state, these films have low dark conductivity ({approximately}10{sup {minus}9}S/cm) and low photoconductivity. Annealing the films at 150 C caused the monohydride dominant films to show photo to dark conductivity ratio near 10{sup 5}. The results also indicate that an increase in monohydride fraction is not linked with a decrease in deposition rate.

Srinivasan, E.; Lloyd, D.A.; Fang, M.; Parsons, G.N. [North Carolina State Univ., Raleigh, NC (United States). Dept. of Chemical Engineering

1996-12-31

118

Hot nanoindentation in inert environments  

E-print Network

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

Trenkle, Jonathan C.

119

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

120

Richtmyer-Meshkov instability in dilute gas-particle mixtures with re-shock  

NASA Astrophysics Data System (ADS)

The Richtmyer-Meshkov instability (RMI) is investigated in a dilute gas-particle mixture using three-dimensional numerical simulations. This work extends an earlier two-dimensional study [S. Ukai, K. Balakrishnan, and S. Menon, "On Richtmyer-Meshkov instability in dilute gas-particle mixtures," Phys. Fluids 22, 104103 (2010)] to a larger parameter space consisting of variations in the mass loading and the particle size as well as considering both single-mode and multi-mode interface initializations. In addition, the effect of the presence of particles on re-shock RMI is also investigated. Single-phase numerical predictions of the mixing layer growth-rate are shown to compare well to both experimental and theoretical results. In a dilute gas-particle mixture, the initial growth-rate of RMI shows similar trends compared to previous work; however, the current numerical predictions show that there is an observable increase, not previously predicted, in the growth of the mixing layer at higher mass loadings. For the range of cases considered, an increase as much as 56% is observed. This increase is attributed to additional vorticity production in the mixing layer resulting from inter-phase momentum coupling. Moreover, the presence of particles introduces a continuous drag on the gas-phase resulting in a delay in the time at which re-shock occurs. This delay, which is observed to be as much as 6%, is largest for higher initial mass loadings and smaller particle radii and has a corresponding effect on both the growth-rate of the mixing-layer after re-shock and the final width of the mixing layer. A new semi-analytical correlation is developed and verified against the numerical data to predict the re-shocked RMI growth-rate in dilute gas-particle flows. The correlation shows that the re-shock RMI growth-rate is linearly proportional to the velocity jump at re-shock, the molecular mixing fraction, and the multi-phase Atwood number. Depending on the initial mass loading and particle radii, the re-shock RMI growth-rates were observed to be reduced by as much as 48% in some cases with variations of around 26% in the width of the mixing layer after re-shock.

Schulz, J. C.; Gottiparthi, K. C.; Menon, S.

2013-11-01

121

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

NASA Astrophysics Data System (ADS)

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

Li, Rong; Yin, Lan

2014-05-01

122

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

123

Characteristics of dilute gas-solids suspensions in drag reducing flow  

NASA Technical Reports Server (NTRS)

Measurements were performed on dilute flowing gas-solids suspensions and included data, with particles present, on gas friction factors, velocity profiles, turbulence intensity profiles, turbulent spectra, and particle velocity profiles. Glass beads of 10 to 60 micron diameter were suspended in air at Reynolds numbers of 10,000 to 25,000 and solids loading ratios from 0 to 4. Drag reduction was achieved for all particle sizes in vertical flow and for the smaller particle sizes in horizontal flow. The profile measurements in the vertical tube indicated that the presence of particles thickened the viscous sublayer. A quantitative theory based on particle-eddy interaction and viscous sublayer thickening has been proposed.

Kane, R. S.; Pfeffer, R.

1973-01-01

124

Di usive scaling of the spectral gap for the dilute Ising lattice gas dynamics below the percolation threshold  

E-print Network

Di#11;usive scaling of the spectral gap for the dilute Ising lattice gas dynamics below a conservative stochastic lattice gas dynamics reversible with respect to the canonical Gibbs measure of the bond gap of the generator of the dynamics in a box of side L centered at the origin scales like L 2

125

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

NASA Astrophysics Data System (ADS)

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

Gensterblum, Y.; Krooss, B. M.

2013-12-01

126

The Production of Polycyclic Aromatic Hydrocarbon Anions in Inert Gas Matrices Doped with Alkali Metals. Electronic Absorption Spectra of the Pentacene Anion (C22H14(-))  

NASA Technical Reports Server (NTRS)

The absorption spectra of pentacene (C22H14) and its radical cation (C22H14(+)) and anion (C22H14(-)) isolated in inert-gas matrices of Ne, Ar, and Kr are reported from the ultraviolet to the near-infrared. The associated vibronic band systems and their spectroscopic assignments are discussed together with the physical and chemical conditions governing ion (and counterion) production in the solid matrix. In particular, the formation of isolated pentacene anions is found to be optimized in matrices doped with alkali metal (Na and K).

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

1999-01-01

127

Dilution rate and microstructure of TIG arc NiAl powder surfacing layer  

Microsoft Academic Search

Surfacing beads are prepared by a direct current tungsten inert gas arc nickel-aluminum (Ni-Al) powder surfacing process.\\u000a With the aim of controlling the dilution rate and obtaining surfacing beads rich in intermetallic compounds, the effects of\\u000a surfacing parameters on geometric parameters, dilution rate, composition, and microstructure of the bead are investigated.\\u000a An assistant cooler, which can potentially reduce the temperature

Jiguo Shan; Wei Dong; Wenda Tan; Di Zhang; Jialie Ren

2007-01-01

128

Extended Le Chatelier's formula and nitrogen dilution effect on the flammability limits  

Microsoft Academic Search

The effect of nitrogen dilution on the flammability limits was measured carefully for a number of fuel gases in order to make an accurate numerical analysis of the data. An extension of Le Chatelier's formula was developed to apply to mixtures containing inert gas. A numerical analysis was carried out using the extended formula for newly measured experimental values of

Shigeo Kondo; Kenji Takizawa; Akifumi Takahashi; Kazuaki Tokuhashi

2006-01-01

129

Process for recovering oxygenated organic compounds from dilute aqueous solutions employing solid sorbent  

SciTech Connect

An oxygenated organic compound, such as ethanol, is recovered from a dilute aqueous stream thereof by contacting said stream with crosslinked polyvinylpyridine resin or nuclear substituted derivative thereof to effect selective sorption of the compound by said resin. The sorbed compound is thereafter removed from the resin by stripping with an inert gas such as carbon dioxide.

Feldman, J.

1984-05-22

130

Exponential approach to, and properties of, a non-equilibrium steady state in a dilute gas  

E-print Network

We investigate a kinetic model of a system in contact with several thermal reservoirs at different temperatures $T_\\alpha$. Our system is a spatially uniform dilute gas whose internal dynamics is described by the nonlinear Boltzmann equation with Maxwellian collisions. Similarly, the interaction with reservoir $\\alpha$ is represented by a Markovian process that has the Maxwellian $M_{T_\\alpha}$ as its stationary state. We prove existence and uniqueness of a non-equilibrium steady state (NESS) and show exponential convergence to this NESS in a metric on probability measures introduced into the study of Maxwellian collisions by Gabetta, Toscani and Wenberg (GTW). This shows that the GTW distance between the current velocity distribution to the steady-state velocity distribution is a Lyapunov functional for the system. We also derive expressions for the entropy production in the system plus the reservoirs which is always positive.

Eric A. Carlen; Joel L. Lebowitz; Clement Mouhot

2014-06-16

131

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

E-print Network

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.

Thomas Schaefer

2010-08-23

132

A quadrature-based kinetic model for a dilute non-isothermal granular gas  

NASA Astrophysics Data System (ADS)

A dilute non-isothermal inelastic granular gas between two stationary Maxwellian walls is studied by means of numerical simulations of the Boltzmann kinetic equation with hard-sphere collisions. The behavior of a granular gas in these conditions is influenced by the thickness of the wall Knudsen layer: if its thickness is not negligible, the traditional description based on the Navier-Stokes-Fourier equations is invalid, and it is necessary to account for the presence of rarefaction effects using high-order solutions of the Boltzmann equation. The system is described by solving the full Boltzmann equation using a quadrature-based moment method (QMOM), with different orders of accuracy in terms of the moments of the distribution function, considering moments up to the seventh order. Four different inelastic collision models (BGK, ES-BGK, Maxwell hard-sphere, Boltzmann hard-sphere) are employed. QMOM results are compared with the predictions of molecular dynamics (MD) simulations of a nearly equivalent system with finite-size particles, showing the agreement of constitutive quantities such as heat flux and stress tensor.

Passalacqua, Alberto; Galvin, Janine; Vedula, Prakash; Hrenya, Christine; Fox, Rodney

2009-11-01

133

Dilution Control in Gas-Tungsten-Arc Welds Involving Superaustenitic Stainless Steels and Nickel-Based Alloys  

E-print Network

Dilution Control in Gas-Tungsten-Arc Welds Involving Superaustenitic Stainless Steels and Nickel) were produced by varying the independent welding parameters of arc power and volumetric filler-Based Alloys S.W. BANOVIC, J.N. DuPONT, and A.R. MARDER Fusion welds were prepared between a superaustenitic

DuPont, John N.

134

Analyzing the safety impact of containment inerting at Vermont Yankee  

E-print Network

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

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

1980-01-01

135

Effects of Gas Temperature Gradient, Pulse Discharge Modulation, and Hydrogen Dilution on Particle Growth in Silane RF Discharges  

Microsoft Academic Search

The effects of gas temperature gradient, pulse discharge modulation, and hydrogen dilution on the growth of particles below about 10 nm in size in silane parallel-plate RF discharges are studied using a high-sensitivity photon-counting laser-light-scattering (PCLLS) method. Thermophoretic force due to the gas temperature gradient between the electrodes drives neutral particles above a few nm in size toward the cool

Masaharu Shiratani; Shinichi Maeda; Kazunori Koga; Yukio Watanabe

2000-01-01

136

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

SciTech Connect

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

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

2010-11-07

137

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

PubMed

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

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

2013-01-01

138

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

139

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

NASA Astrophysics Data System (ADS)

Motivated by recent experiments addressing the issue of itinerant ferromagnetism in a dilute ultra-cold Fermi gas with contact interaction, we examine ground state properties of the repulsive Hubbard model on a cubic lattice [1] by means of a very accurate auxiliary-field quantum Monte Carlo method [2]. We focus on low-density systems with varying on-site interaction U/t, in the range relevant to the experiments. Twist-averaged 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 [2]. We find no ferromagnetic phase transition in this model. The ground-state correlations are consistent with those of a paramagnetic Fermi liquid. [4pt] [1] Chia-Chen Chang, Shiwei Zhang, and David M. Ceperley, arXiv:1009.1409[0pt] [2] Chia-Chen Chang and Shiwei Zhang, Phys. Rev. B 78, 165101 (2008).

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

2011-03-01

140

Measurement of activity coefficients at infinite dilution for acetonitrile, water, limonene, limonene epoxide and their binary pairs  

Microsoft Academic Search

Activity coefficients at infinite dilution were determined for binary pairs of acetonitrile, water, limonene and limonene epoxide at room temperature using the dilutor technique (inert gas stripping) in a home-made dilutor apparatus. The activity coefficients were predicted with the Aspen Plus software using the Dortmund-modified UNIFAC contribution method. Values predicted by software simulations are in good agreement with experimental data.

Rolando Barrera Zapata; Aída Luz Villa; Consuelo Montes de Correa

2009-01-01

141

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

142

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

143

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

144

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

PubMed

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

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

2006-09-01

145

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

PubMed

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

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

2010-11-01

146

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

NASA Astrophysics Data System (ADS)

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

Orsi, Anais J.

147

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

148

Hydrogen\\/dust explosion hazard in ITER: Effect of nitrogen dilution on explosion behavior of hydrogen\\/tungsten dust\\/air mixtures  

Microsoft Academic Search

The work is aimed at supporting inert-gas dilution method proposed to mitigate hydrogen\\/dust explosion hazard in ITER in case of severe accidents. A standard method of 20-l sphere is used to study the effect of nitrogen dilution on the explosion behavior of 0.5-?m tungsten dust dispersed in hydrogen-containing air atmospheres. The oxygen content varied from normal 21 to 10vol.%. The

A. Denkevits

2010-01-01

149

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...

150

Respiratory and plumage gas volumes in unrestrained diving ducks ( Aythya affinis)  

Microsoft Academic Search

Closed-circuit plethysmography and inert gas equilibration analysis were used to measure the volumes of gas in the respiratory system and plumage at the end of voluntary dives in unrestrained lesser scaup (Aythya affinis). Total (respiratory plus plumage) gas volumes were measured by helium dilution and estimated from body mass, body tissue density and buoyant force. These two techniques yielded results

Richard Stephenson

1995-01-01

151

Biophysics of Inert Gases Related to Diving.  

National Technical Information Service (NTIS)

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

G. L. Pollack

1982-01-01

152

Ab initio potential energy surface for the carbon dioxide molecule pair and thermophysical properties of dilute carbon dioxide gas  

NASA Astrophysics Data System (ADS)

A four-dimensional intermolecular potential energy surface (PES) for two rigid carbon dioxide molecules was determined from quantum-chemical ab initio calculations. Interaction energies for 1229 CO2-CO2 configurations were computed at the CCSD(T) level of theory using basis sets up to aug-cc-pVQZ supplemented with bond functions. An analytical site-site potential function with seven sites per CO2 molecule was fitted to the interaction energies. The PES was validated by calculating the second virial coefficient as well as viscosity and thermal conductivity in the dilute-gas limit.

Hellmann, Robert

2014-10-01

153

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

1999-05-01

154

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

PubMed

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

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

2014-03-01

155

Ionization effect in the front of a weak shock wave propagating in an inert gas diluted by a small amount of Mo(CO)6  

Microsoft Academic Search

The propagation of shock waves in He and Ar containing 0.01% of molybdenum hexacarbonyl Mo(CO)6 as a heavy component of the mixture has been investigated with the use of the method of multichannel emission spectroscopy and an electrostatic probe with a spatial resolution of 0.2 mm placed in the core of a flow. The measurements have been carried out in

V. S. Ziborov; V. P. Efremov; V. E. Fortov

2007-01-01

156

Ionization effect in the front of a weak shock wave propagating in an inert gas diluted by a small amount of Mo(CO) 6  

Microsoft Academic Search

The propagation of shock waves in He and Ar containing 0.01% of molybdenum hexacarbonyl Mo(CO)6 as a heavy component of the mixture has been investigated with the use of the method of multichannel emission spectroscopy\\u000a and an electrostatic probe with a spatial resolution of 0.2 mm placed in the core of a flow. The measurements have been carried\\u000a out in

V. S. Ziborov; V. P. Efremov; V. E. Fortov

2007-01-01

157

Inert gas ion source program  

NASA Technical Reports Server (NTRS)

THe original 12 cm hexagonal magneto-electrostatic containment discharge chamber has been optimized for argon and xenon operation. Argon mass utilization efficiencies of 65 to 77 percent were achieved at keeper-plus-main discharge energy consumptions of 200 to 458 eV/ion, respectively. Xenon performance of 84 to 96 percent mass utilization was realized at 203 to 350 eV/ion. The optimization process and test results are discussed.

Ramsey, W. D.

1978-01-01

158

Inert gas ion thruster development  

NASA Technical Reports Server (NTRS)

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

Ramsey, W. D.

1980-01-01

159

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

Microsoft Academic Search

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

Greuer

1974-01-01

160

Methanol Droplet Combustion in Oxygen-Inert Environments in Microgravity  

NASA Technical Reports Server (NTRS)

The Flame Extinguishment (FLEX) experiment that is currently underway in the Combustion Integrated Rack facility onboard the International Space Station is aimed at understanding the effects of inert diluents on the flammability of condensed phase fuels. To this end, droplets of various fuels, including alkanes and alcohols, are burned in a quiescent microgravity environment with varying amounts of oxygen and inert diluents to determine the limiting oxygen index (LOI) for these fuels. In this study we report experimental observations of methanol droplets burning in oxygen-nitrogen-carbon dioxide and oxygen-nitrogen-helium gas mixtures at 0.7 and 1 atmospheric pressures. The initial droplet size varied between approximately 1.5 mm and 4 mm to capture both diffusive extinction brought about by insufficient residence time at the flame and radiative extinction caused by excessive heat loss from the flame zone. The ambient oxygen concentration varied from a high value of 30% by volume to as low as 12%, approaching the limiting oxygen index for the fuel. The inert dilution by carbon dioxide and helium varied over a range of 0% to 70% by volume. In these experiments, both freely floated and tethered droplets were ignited using symmetrically opposed hot-wire igniters and the burning histories were recorded onboard using digital cameras, downlinked later to the ground for analysis. The digital images yielded droplet and flame diameters as functions of time and subsequently droplet burning rate, flame standoff ratio, and initial and extinction droplet diameters. Simplified theoretical models correlate the measured burning rate constant and the flame standoff ratio reasonably well. An activation energy asymptotic theory accounting for time-dependent water dissolution or evaporation from the droplet is shown to predict the measured diffusive extinction conditions well. The experiments also show that the limiting oxygen index for methanol in these diluent gases is around 12% to 13% oxygen by volume.

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

2013-01-01

161

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

162

Characteristics of NO x emission with flue gas dilution in air and fuel sides  

Microsoft Academic Search

Flue gas recirculation (FGR) is a method widely adopted to control NOx in combustion system. The recirculated flue gas decreases flame temperature and reaction rate, resulting in the decrease\\u000a in thermal NO production. Recently, it has been demonstrated that the recirculated flue gas in fuel stream, that is, the fuel\\u000a induced recirculation (FIR), could enhance a much improved reduction in

Eun-Seong Cho; Suk Ho Chung

2004-01-01

163

Stable isotope dilution gas chromatography-mass spectrometry for quantification of thymoquinone in black cumin seed oil.  

PubMed

Black cumin seed (Nigella sativa L.) is a widely used spice and herb, where thymoquinone (2-isopropyl-5-methyl-1,4-benzoquinone) is the major bioactive compound. Here, a stable isotope dilution (SID) gas chromatography-mass spectrometry (GC-MS) technique was developed for the quantification of thymoquinone. A doubly deuterated thymoquinone ([(2)H2]-thymoquinone) was synthesized for the first time with more than 93% deuteration degree shown by mass spectrometry and proton nuclear magnetic resonance ((1)H NMR). This compound was used as an internal standard for the quantification of thymoquinone using a SID GC-MS method. The validation experiment showed a recovery rate of 99.1 ± 1.1% relative standard deviation (RSD). Standard addition and external calibration methods have also been used to quantify thymoquinone, which cross-validated the developed stable isotope dilution assay (SIDA). In comparison to external calibration and standard addition methods, the SIDA method is robust and accurate. The concentration of thymoquinone in five marketed black cumin seed oils ranged between 3.34 and 10.8 mg/mL by use of SID GC-MS. PMID:24871868

Johnson-Ajinwo, Okiemute Rosa; Li, Wen-Wu

2014-06-18

164

Simplified absolute metabolite quantification by gas chromatography-isotope dilution mass spectrometry on the basis of commercially available source material.  

PubMed

In the field of metabolomics, GC-MS has rather established itself as a tool for semi-quantitative strategies like metabolic fingerprinting or metabolic profiling. Absolute quantification of intra- or extracellular metabolites is nowadays mostly accomplished by application of diverse LC-MS techniques. Only few groups have so far adopted GC-MS technology for this exceptionally challenging task. Besides numerous and deeply investigated problems related to sample generation, the pronounced matrix effects in biological samples have led to the almost mandatory application of isotope dilution mass spectrometry (IDMS) for the accurate determination of absolute metabolite concentrations. Nevertheless, access to stable isotope labeled internal standards (ILIS), which are in many cases commercially unavailable, is quite laborious and very expensive. Here we present an improved and simplified gas chromatography-isotope dilution mass spectrometry (GC-IDMS) protocol for the absolute determination of intra- and extracellular metabolite levels. Commercially available (13)C-labeled algal cells were used as a convenient source for the preparation of internal standards. Advantages as well as limitations of the described method are discussed. PMID:22100557

Vielhauer, Oliver; Zakhartsev, Maksim; Horn, Thomas; Takors, Ralf; Reuss, Matthias

2011-12-15

165

Experimental investigation on dilute gas-solid multiphase jet in crossflow  

Microsoft Academic Search

In the current study, an experimental setup was built to investigate the gas flow and particle distribution in a normal jet\\u000a crossflow to a main flow in a confined test section. The experiments were conducted under two test conditions: with Rec\\/Rejet of 7.9×104\\/3.1×104 and 7.0×104\\/1.8×104. Four classes of particles were used in both tests. The planar gas flow field and

Yao Fu; Tong Wang; Chuangang Gu

2011-01-01

166

Effect of inert propellant injection on Mars ascent vehicle performance  

NASA Technical Reports Server (NTRS)

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

Colvin, James E.; Landis, Geoffrey A.

1992-01-01

167

Method of producing hydrogen, and rendering a contaminated biomass inert  

DOEpatents

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

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

2010-02-23

168

Quantifying gross fluxes of nitrous oxide and dinitrogen gas using a novel isotope pool dilution technique  

Microsoft Academic Search

One of the existing challenges in trace gas biogeochemistry lies in understanding the environmental controls on the net and gross fluxes of soil-derived compounds. This is because gross production and consumption fluxes of these gases often occur simultaneously or in close spatial proximity, making it difficult to make inferences about the effects of environmental variables (e.g. temperature, soil water content,

Yit Arn Teh; Wendy Yang; Whendee L. Silver

2010-01-01

169

Laboratory experimental testing of inerters  

Microsoft Academic Search

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

Christakis Papageorgiou; Malcolm C. Smith

2005-01-01

170

Argon gas dilution effect on the properties of amorphous carbon nitride thin films  

Microsoft Academic Search

Optical and structural properties of amorphous carbon nitride (a-C:Nx) thin films deposited on p-type silicon (p-Si) and quartz substrates by microwave (MW) surface-wave plasma (SWP) chemical vapor deposition (CVD) at low temperature (<100 °C) were analyzed in this paper. Argon (Ar: 100 sccm ?300 sccm) was used as carrier gas while acetylene (C2H2: 5 sccm) and nitrogen (N: 5 sccm) were used as plasma source.

Hare Ram Aryal; Sudip Adhikari; Dilip Chandra Ghimire; Hideo Uchida; Masayoshi Umeno

2007-01-01

171

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

172

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

173

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

174

On Richtmyer-Meshkov instability in dilute gas-particle mixtures  

NASA Astrophysics Data System (ADS)

Richtmyer-Meshkov instability (RMI) in gas-particle mixtures is investigated both numerically and analytically. The linear amplitude growth rate for a RMI in a two-phase mixture is derived by using a dusty gas formulation for small Stokes number (St ?1.0), and it is shown that the problem can be characterized by mass loading and St. The model predictions are compared with numerical results under two conditions, i.e., a shock wave hitting (1) a perturbed species interface of air and SF6 surrounded by uniformly distributed particles, and (2) a perturbed shape particle cloud in uniform air. In the first case, the interaction between the instability of the species perturbation and the particles is investigated. The multiphase growth model accurately predicts the growth rates when St ?1.0, and the amplitude growth normalized by the two-phase RMI velocity shows good agreement with the single-phase RMI growth rate as well. It is also shown that the two-phase model results are in accordance with the growth rates obtained from the simulations even for cases corresponding to St ?10. However, for St ?10, particles do not follow the RMI motion, and the RMI growth rate agrees with the original Richtmyer's model [R. D. Richtmyer, "Taylor instability in shock acceleration of compressible fluids," Commun. Pure Appl. Math. 13, 297 (1960)]. Preferential concentration of particles are observed around the RMI roll-ups at late times when St is of order unity, whereas when St ?1.0, the particles respond rapidly to the flow, causing them to distribute within the roll-ups. In the second problem, the two-phase RMI growth model is extended to study whether a perturbed dusty gas front shows RMI-like growth due to the impact of a shock wave. When St ?1.0, good agreement with the multiphase model is again seen. Moreover, the normalized growth rates are very close to the single-phase RMI growth rates even at late times, which suggest that the two-phase growth model is applicable to this type of perturbed shape particle clouds as well. However, when St is close to unity or larger (St >1.0), the particles do not experience impulsive acceleration but rather a continuous one, which results in exponential growth rates as seen in a Rayleigh-Taylor instability.

Ukai, Satoshi; Balakrishnan, Kaushik; Menon, Suresh

2010-10-01

175

Gas-liquid chromatography measurements of activity coefficients at infinite dilution of hydrocarbons and alkanols in 1-alkyl-3-methylimidazolium bis(oxalato)borate  

Microsoft Academic Search

The activity coefficients at infinite dilution, ?i? for various solutes: alkanes, cycloalkanes, 1-alkenes, 1-alkynes, benzene, alkylbenzenes, and alcohols in the ionic liquids 1-butyl-3-methylimidazolium bis(oxalato)borate [BMIM][BOB] and 1-hexyl-3-methyl-imidazolium bis(oxalato)borate [HMIM][BOB] have been determined by gas-liquid chromatography at the temperatures ranging from 308 to 348K. The partial molar excess enthalpies at infinite dilution HiE,? of the solutes in the ionic liquids were

Pei-Fang Yan; Miao Yang; Chang-Ping Li; Xiu-Mei Liu; Zhi-Cheng Tan; Urs Welz-Biermann

2010-01-01

176

Combustion selective temperature dilution  

SciTech Connect

In a gas turbine engine having a hot gas flowing in an annular path partially defined by inner and outer liners of a combustor and inner and outer vane shrouds, the combustor including at its upstream end injectors for admitting an original mixture of air and fuel to the upstream end of the combustor for burning of the mixture in the combustor, the improvement is described comprising: circumferentially spaced-apart stationary turbine vanes disposed in the hot gas flow path downstream of the combustor; circumferentially spaced-apart dilution apertures disposed in the combustor downstream of the injectors, upstream of the turbine vanes and in axial alignment with leading edges of the turbine vanes, for admitting dilution air into the combustor for mixing with the original mixture to promote partial mixing thereof; and circumferentially spaced dilution apertures for admitting dilution air into the combustor to promote partial mixing with the original mixture. The first and second apertures are axially located in a secondary combustion zone of the combustor and upstream of the turbine vanes to induce partial mixing of the dilution air with the hot gases for generating a preselected circumferential temperature gradient in the hot gas for providing a flow of hot gas at a relatively higher temperature through the gaps and a flow of hot gas at relatively lower temperature upon the turbine vanes.

Vdoviak, J.W.; Weinstein, B.

1988-03-29

177

Four frequently used test systems for serum cholesterol evaluated by isotope dilution gas chromatography-mass spectrometry candidate reference method.  

PubMed

We evaluated the performance of four frequently used cholesterol test systems, using split-sample measurements with a panel of 79 patients' specimens and isotope dilution gas chromatography-mass spectrometry (ID GS-MS) as a comparison method. The test systems were from Beckman, a Boehringer Mannheim, Merck, and Johnson & Johnson Clinical Diagnostics, performed on the Synchron CX7, Hitachi 717, Mega, and Ektachem 250 analyzers, respectively. The liner regression data for the method comparison [ID GS-MS as independent variable (x)] were for Beckman: slope = 1.012, intercept = 0.0243 mmol/L, dispersion (S(y/x)) = 0.1303 mmol/l, and correlation coefficient (r) = 0.9867; for Boehringer Mannheim: slope = 1.002, intercept = 0.114 mmol/L, Sy/x = 0.0759 mmol/L, r = 0.9954; for Merck: slope = 1.034, intercept = -0.0613 mmol/L, Sy/x = 0.0886 mmol/L, r = 0.9941; and for Johnson & Johnson Clinical Diagnostics: slope = 1.007, intercept = 0.01 mmol/L, Sy/x = 0.15 mmol/L, and r = 0.9811. These data demonstrate excellent state-of-the-art cholesterol measurement for some of the most widely used test systems. PMID:8605669

Thienpont, L M; Van Landuyt, K G; Stöckl, D; De Leenheer, A P

1996-04-01

178

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

...section. (f) Each oxygen or hydrocarbon analyzer required by this section must— (1) Be installed in accordance with API 550 (incorporated by reference, see 33 CFR 154.106); (2) Have a system response time of not more than one minute...

2014-07-01

179

Simultaneous supercritical fluid extraction and chemical derivatization for the gas chromatographic–isotope dilution mass spectrometric determination of amphetamine and methamphetamine in urine  

Microsoft Academic Search

An in-situ supercritical fluid extraction (SFE) and chemical derivatization (ChD) procedure followed by gas chromatography–isotope dilution mass spectrometry (GC–MS) for the determination of amphetamines in urine is described and evaluated. While using celite as the SFE wet-support, the one-pot sample pretreatment procedure also employs ammonium water to alkalize the urine matrix that contains protonated amphetamine (AP) and methamphetamine (MA). The

Sheng-Meng Wang; Yun-Seng Giang; Yong-Chien Ling

2001-01-01

180

Examination of charge dilution with EGR to reduce NO{sub x} emissions from a natural gas-fuelled 16 valve DOHC four-cylinder engine  

SciTech Connect

Charge dilution is commonly used to reduce emissions of nitrogen oxides (NO{sub x}) from internal combustion engine exhaust gas. The question of whether to use air or exhaust gas recirculation (EGR) as a charge diluent for the natural gas-fuelled test engine is addressed first. The decision to use EGR is based on the potentially lower NO{sub x} and unburned hydrocarbon emissions that could be achieved if a three-way catalyst were applied to the engine. The effect of EGR on the spark advance for maximum brake torque (MBT), NO{sub x}, and unburned hydrocarbon emissions is then examined in detail. The effect on fuel efficiency is discussed briefly. 37 refs., 16 figs., 3 tabs.

Jaeaeskelaeinen, H.E.; Wallace, J.S.

1994-10-01

181

Effects of hydrogen dilution of silane\\/methane gas mixtures on growth and structure of aSi 1?xC x:H alloys  

Microsoft Academic Search

In this paper we have studied amorphous hydrogenated silicon-carbon, a-Si1?xCx:H, films grown by ultra high vacuum plasma enhanced chemical vapor deposition in undiluted and hydrogen diluted SiH4+CH4 gas mixtures, having energy gap in the range 2.1–3.2 eV. The films have been characterized in optical properties by transmittance-reflectance spectroscopy. The elemental composition has been determined by Rutherford back-scattering and elastic recoil

F. Demichelis; F Giorgis; C. F Pirri

1995-01-01

182

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 affect…

Fishel, Laurence A.

2010-01-01

183

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

184

Activity coefficients at infinite dilution of organic solutes in the ionic liquid 1-butyl-3-methylimidazolium hexafluoroantimonate using gas–liquid chromatography at T = (313.15, 323.15, and 333.15) K  

Microsoft Academic Search

Activity coefficients at infinite dilution were determined for 27 solutes: n-alkanes, alk-1-enes, alk-1-ynes, cycloalkanes, alkylbenzenes, alcohols, and ketones in the ionic liquid 1-butyl-3-methylimidazolium hexafluoroantimonate, [BMIM][SbF6], by gas–liquid chromatography at three different temperatures, T=(313.15, 323.15, and 333.15)K. The results are compared to published data on related compounds. The partial molar excess enthalpy values at infinite dilution were calculated from the experimental

Eugene Olivier; Trevor M. Letcher; Paramespri Naidoo; Deresh Ramjugernath

2011-01-01

185

Modelling of non-catalytic reactions in a gas-solid trickle flow reactor: dry, regenerative flue gas desulphurization using a silica-supported copper oxide sorbent  

Microsoft Academic Search

A one-dimensional, two-phase dispersed plug flow model has been developed to describe the steady-state performance of a relatively new type of reactor, the gas-solid trickle flow reactor (GSTFR). In this reactor, an upward-flowing gas phase is contacted with as downward-flowing dilute solids phase over an inert packing. The model is derived from the separate mass heat balances for both the

J. H. A. Kiel; W. Prins; Swaaij van W. P. M

1992-01-01

186

-Based Cermet Inert Anodes for Aluminum Electrolysis  

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

187

Flame extinguishing in the cup-burner by inert gases  

Microsoft Academic Search

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

Joseph A. Senecal

2005-01-01

188

Detection and quantification of 1,N6-ethenoadenine in human urine by stable isotope dilution capillary gas chromatography/negative ion chemical ionization/mass spectrometry.  

PubMed

1,N(6)-Ethenoadenine (epsilonAde) is a promutagenic lesion detected in tissue DNA; it has been shown that epsilonAde can be repaired by human DNA glycosylases, and it is expected to be excreted in urine. In this paper, we present for the first time detection and accurate quantification of epsilonAde in human urine samples by a highly sensitive and specific stable isotope dilution gas chromatography/negative ion chemical ionization/mass spectrometric assay (GC/NICI/MS). Analysis by GC/NICI/MS includes adduct enrichment by a solid phase extraction column, followed by electrophore labeling and postderivatization cleanup. Using selective ion monitoring mode, the assay allows quantification of 0.5 pg of epsilonAde in as little as 0.1 mL of the urine sample, which is equivalent to corresponding concentration quantification limit of 31 pM. Using this assay, concentrations of epsilonAde in the 24 h urine samples of 23 healthy individuals were determined, which ranged from 0 to 124 pg/mL. After we adjusted for creatinine, a statistically significant correlation was found between epsilonAde excretion and cigarette smoking in males (p = 0.03). Thus, this stable isotope dilution GC/NICI/MS assay offers a sensitive and accurate quantification of urinary epsilonAde as a potential biomarker for oxidative damage of DNA and repair. PMID:12971797

Chen, Hauh-Jyun Candy; Chiu, Wei-Loong

2003-09-01

189

The measurement of theophylline in human serum or plasma using gas chromatography and isotope dilution-mass spectrometry (GC-IDMS) taking other substituted xanthines into consideration.  

PubMed

A method is described which uses a combination of gas chromatography and isotope dilution-mass spectrometry (GC-IDMS) to determine the concentration of theophylline (1,3-dimethyl xanthine) in human plasma or serum samples. The effects of similar substituted xanthines - namely theobromine (3,7-dimethyl xanthine), paraxanthine (1,7-dimethyl xanthine) 1,3-dimethyl-7-(2-hydroxyethyl) xanthine (internal standard HPLC) and caffeine (1,3,7-trimethyl xanthine) were tested to confirm the specificity of the method. The derivatisation of all xanthines was performed with N-methyl-N-trimethylsilyl trifluroacetamide (MSTFA). The internal standard used was 2-(13)C ,1,3-(15)N2-theophylline. The extraction and derivatisation procedures were examined in detail and optimised stepwise during the development of the method. High-performance liquid chromatography (HPLC) was used for comparison. PMID:12389715

Kress, Michael; Meissner, Dieane; Kaiser, Patricia; Hanke, Rainer; Wood, William Graham

2002-01-01

190

Infrared reflectivity spectra of gas-source molecular beam epitaxy grown dilute InN{sub x}As{sub 1-x}/InP (001)  

SciTech Connect

Vibrational spectra of gas-source molecular beam epitaxy grown dilute InN{sub x}As{sub 1-x}/InP (001) alloys are obtained using a Fourier-transform infrared (IR) spectroscopy. A triply degenerate N{sub As} local vibrational mode of T{sub d}-symmetry is observed near 438 cm{sup -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 N{sub As} local mode into a doublet for the N{sub As}-Ga{sub 1}(In{sub 1})In{sub 3}(Ga{sub 3}) pair-defect of C{sub 3v}-symmetry is consistent with our simulated results based on a sophisticated Green's function theory.

Talwar, Devki N. [Department of Physics, Indiana University of Pennsylvania, 975 Oakland Avenue, 56 Weyandt Hall, Indiana, Pennsylvania 15705-1087 (United States)] [Department of Physics, Indiana University of Pennsylvania, 975 Oakland Avenue, 56 Weyandt Hall, Indiana, Pennsylvania 15705-1087 (United States); Yang, Tzuen-Rong [Department of Physics, National Taiwan Normal University, Taipei 106-11, Taiwan (China)] [Department of Physics, National Taiwan Normal University, Taipei 106-11, Taiwan (China); Hsiung Lin, Hao; Chuan Feng, Zhe [Institute of Photonics and Optoelectronics, Department of Electrical Engineering and Center for Engineering Material and Advanced Devices National Taiwan University, Taipei 106-17, Taiwan (China)] [Institute of Photonics and Optoelectronics, Department of Electrical Engineering and Center for Engineering Material and Advanced Devices National Taiwan University, Taipei 106-17, Taiwan (China)

2013-02-04

191

7 CFR 201.19 - Inert matter.  

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

2014-01-01

192

Inert doublet model and LEP II limits  

SciTech Connect

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

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

2009-02-01

193

Quantitation of Red Blood Cell Folates by Stable Isotope Dilution Gas Chromatography-Mass Spectrometry Utilizing a Folate Internal Standard  

Microsoft Academic Search

We report a new gas chromatography-mass spectrometry (GC-MS) method of measurement of red blood cell folates utilizing a stable isotope-labeled bacterial synthesized folate internal standard. The GC-MS method exploits the fact that the common feature of all folate molecules is a p-aminobenzoic acid moiety sandwiched between a pteridine ring and a polyglutamate chain of varying length. In this method, red

C. R. Santhoshkumar; J. C. Deutsch; K. L. Hassell; N. M. Kolhouse; J. F. Kolhouse

1995-01-01

194

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

NASA Astrophysics Data System (ADS)

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

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

2011-05-01

195

Characterization of the major odor-active compounds in Thai durian ( Durio zibethinus L. 'Monthong') by aroma extract dilution analysis and headspace gas chromatography-olfactometry.  

PubMed

An aroma extract dilution analysis applied on the volatile fraction isolated from Thai durian by solvent extraction and solvent-assisted flavor evaporation resulted in 44 odor-active compounds in the flavor dilution (FD) factor range of 1-16384, 41 of which could be identified and 24 that had not been reported in durian before. High FD factors were found for ethyl (2S)-2-methylbutanoate (fruity; FD 16384), ethyl cinnamate (honey; FD 4096), and 1-(ethylsulfanyl)ethanethiol (roasted onion; FD 1024), followed by 1-(ethyldisulfanyl)-1-(ethylsulfanyl)ethane (sulfury, onion), 2(5)-ethyl-4-hydroxy-5(2)-methylfuran-3(2H)-one (caramel), 3-hydroxy-4,5-dimethylfuran-2(5H)-one (soup seasoning), ethyl 2-methylpropanoate (fruity), ethyl butanoate (fruity), 3-methylbut-2-ene-1-thiol (skunky), ethane-1,1-dithiol (sulfury, durian), 1-(methylsulfanyl)ethanethiol (roasted onion), 1-(ethylsulfanyl)propane-1-thiol (roasted onion), and 4-hydroxy-2,5-dimethylfuran-3(2H)-one (caramel). Among the highly volatile compounds screened by static headspace gas chromatography-olfactometry, hydrogen sulfide (rotten egg), acetaldehyde (fresh, fruity), methanethiol (rotten, cabbage), ethanethiol (rotten, onion), and propane-1-thiol (rotten, durian) were found as additional potent odor-active compounds. Fourteen of the 41 characterized durian odorants showed an alkane-1,1-dithiol, 1-(alkylsulfanyl)alkane-1-thiol, or 1,1-bis(alkylsulfanyl)alkane structure derived from acetaldehyde, propanal, hydrogen sulfide, and alkane-1-thiols. Among these, 1-(propylsulfanyl)ethanethiol, 1-{[1-(methylsulfanyl)ethyl]sulfanyl}ethanethiol, and 1-{[1-(ethylsulfanyl)ethyl]sulfanyl}ethanethiol were reported for the first time in a natural product. PMID:23088286

Li, Jia-Xiao; Schieberle, Peter; Steinhaus, Martin

2012-11-14

196

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  

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 chromatography–mass spectrometry (GC–MS) 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

197

Polarization rotation for light propagating non-parallel to a magnetic field in vacuum and in a dilute electron gas  

E-print Network

We study quantitatively the rotation of the polarization of light propagating perpendicular to an external magnetic field $B$ in QED vacuum and in an electron gas, by starting from the low frequency limit of the expressions for the photon self-energy in a constant external magnetic field. In both media, due to birefringence, the polarization vector describes an ellipse whose axes vary periodically. The results obtained for magnetized quantum vacuum are below the observed values reported in PVLAS experiments, but by assuming a remnant electron density of order $10^4/ cm^{-3}$, as might result from ionization of the molecules in the experimental medium, the rotation of the polarization plane would be compatible with the measured values.

Rojas, H Perez

2007-01-01

198

Dilution in single pass arc welds  

SciTech Connect

A study was conducted on dilution of single pass arc welds of type 308 stainless steel filler metal deposited onto A36 carbon steel by the plasma arc welding (PAW), gas tungsten arc welding (GTAW), gas metal arc welding (GMAW), and submerged arc welding (SAW) processes. Knowledge of the arc and melting efficiency was used in a simple energy balance to develop an expression for dilution as a function of welding variables and thermophysical properties of the filler metal and substrate. Comparison of calculated and experimentally determined dilution values shows the approach provides reasonable predictions of dilution when the melting efficiency can be accurately predicted. The conditions under which such accuracy is obtained are discussed. A diagram is developed from the dilution equation which readily reveals the effect of processing parameters on dilution to aid in parameter optimization.

DuPont, J.N.; Marder, A.R. [Lehigh Univ., Bethlehem, PA (United States). Dept. of Materials Science and Engineering

1996-06-01

199

Determination of nerve agent metabolites in human urine by isotope-dilution gas chromatography-tandem mass spectrometry after solid phase supported derivatization.  

PubMed

A simple and sensitive method has been developed and validated for determining ethyl methylphosphonic acid (EMPA), isopropyl methylphosphonic acid (IMPA), isobutyl methylphosphonic acid (iBuMPA), and pinacolyl methylphosphonic acid (PMPA) in human urine using gas chromatography-tandem mass spectrometry (GC-MS/MS) coupled with solid phase derivatization (SPD). These four alkyl methylphosphonic acids (AMPAs) are specific hydrolysis products and biomarkers of exposure to classic organophosphorus (OP) nerve agents VX, sarin, RVX, and soman. The AMPAs in urine samples were directly derivatized with pentafluorobenzyl bromide on a solid support and then extracted by liquid-liquid extraction. The analytes were quantified with isotope-dilution by negative chemical ionization (NCI) GC-MS/MS in a selected reaction monitoring (SRM) mode. This method is highly sensitive, with the limits of detection of 0.02 ng/mL for each compound in a 0.2 mL sample of human urine, and an excellent linearity from 0.1 to 50 ng/mL. It is proven to be very suitable for the qualitative and quantitative analyses of degradation markers of OP nerve agents in biomedical samples. PMID:24633564

Lin, Ying; Chen, Jia; Yan, Long; Guo, Lei; Wu, Bidong; Li, Chunzheng; Feng, Jianlin; Liu, Qin; Xie, Jianwei

2014-08-01

200

Physicochemical characterization of d-mannitol polymorphs: The challenging surface energy determination by inverse gas chromatography in the infinite dilution region.  

PubMed

Nowadays, it is well known that surface interactions play a preponderant role in mechanical operations, which are fundamental in pharmaceutical processing and formulation. Nevertheless, it is difficult to correlate surface behaviour in processes to physical properties measurement. Indeed, most pharmaceutical solids have multiple surface energies because of varying forms, crystal faces and impurities contents or physical defects, among others. In this paper, d-mannitol polymorphs (?, ? and ?) were studied through different characterization techniques highlighting bulk and surface behaviour differences. Due to the low adsorption behaviour of ? and ? polymorphs, special emphasis has been paid to surface energy analysis by inverse gas chromatography, IGC. Surface energy behaviour has been studied in Henry's domain showing that, for some organic solids, the classical IGC infinite dilution zone is never reached. IGC studies highlighted, without precedent in literature, dispersive surface energy differences between ? and ? mannitol, with a most energetically active ? form with a ?s(d) of 74.9mJ·m(-2). Surface heterogeneity studies showed a highly heterogeneous ? mannitol with a more homogeneous ? (40.0mJ.m(-2)) and ? mannitol (40.3mJ·m(-2)). Moreover, these last two forms behaved similarly considering surface energy at different probe concentrations. PMID:25151549

Cares-Pacheco, M G; Vaca-Medina, G; Calvet, R; Espitalier, F; Letourneau, J-J; Rouilly, A; Rodier, E

2014-11-20

201

[Determination of urinary cotinine of children exposed to passive smoking by stable isotope dilution gas chromatography-triple quadrupole mass spectrometry].  

PubMed

An analytical method for the determination of urinary cotinine of children exposed to passive smoking was established based on stable isotope dilution by gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS). The samples were extracted and purified with chloroform. The extracts were determined by GC-MS/MS in multiple reaction monitoring (MRM) mode. The cotinine-d3 as an isotope internal standard was applied to quantify and confirm the urinary cotinine of children exposed to passive smoking. The method had a good linearity from 0.1 microg/L to 10 microg/L with the correlation coefficient (r) > 0.998. The recoveries of the cotinine in blank urine were from 79.2% to 112.8% at spiked levels of 0.1, 1.0 and 10 microg/ L, with relative standard deviations (RSDs) from 2.1% to 5. 8%. The limit of quantification ( LOQ) of the method was 0.1 microg/L. The developed method is accurate, sensitive, rapid and can be applied to detect urinary cotinine of children exposed to passive smoking at home. PMID:25269267

Wang, Yun; Huang, Zhiqiang; Ye, Ying; Zhang, Ying; Xiao, Shuiyuan

2014-06-01

202

Retrospective estimation of values for total lung capacity by plethysmography, helium gas dilution, and chest radiography in patients with cystic fibrosis  

Microsoft Academic Search

In children with cystic fibrosis, total lung capacity was estimated by helium dilution, plethysmography, and radiography. None of these methods should be used interchangeably as the 95% confidence intervals for estimating were large at 58-144% for radiography and 45.3-100.4% for helium dilution.

R Cutrera; P Helms

1988-01-01

203

Thermodynamics of Dilute Solutions.  

ERIC Educational Resources Information Center

Discusses principles and definitions related to the thermodynamics of dilute solutions. Topics considered include dilute solution, Gibbs-Duhem equation, reference systems (pure gases and gaseous mixtures, liquid mixtures, dilute solutions), real dilute solutions (focusing on solute and solvent), terminology, standard states, and reference systems.…

Jancso, Gabor; Fenby, David V.

1983-01-01

204

Flammability limits of dusts: Minimum inerting concentrations  

SciTech Connect

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

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

1999-05-01

205

40 CFR 1065.546 - Validation of minimum dilution ratio for PM batch sampling.  

Code of Federal Regulations, 2010 CFR

...dilution ratio for PM batch sampling. 1065.546 Section...dilution ratio for PM batch sampling. Use continuous flows and/or tracer gas concentrations for transient...dilution ratios for PM batch sampling as specified in §...

2010-07-01

206

Simultaneous supercritical fluid extraction and chemical derivatization for the gas chromatographic-isotope dilution mass spectrometric determination of amphetamine and methamphetamine in urine.  

PubMed

An in-situ supercritical fluid extraction (SFE) and chemical derivatization (ChD) procedure followed by gas chromatography-isotope dilution mass spectrometry (GC-MS) for the determination of amphetamines in urine is described and evaluated. While using celite as the SFE wet-support, the one-pot sample pretreatment procedure also employs ammonium water to alkalize the urine matrix that contains protonated amphetamine (AP) and methamphetamine (MA). The mean recoveries achieved by simultaneous SFE-ChD, i.e., 95% (RSD=3.8%) for AP and 89% (RSD=4.0%) for MA, are significantly better than the corresponding overall recoveries obtained upon stepwise SFE-ChD, suggesting the unreacted trifluoroacetic anhydride (TFA) in the former procedure has strengthened the extracting power of CO, fluid as has been evidenced by a control test. As to GC-MS analysis, the optimal qualitative ions and quantitative ions of the respective analytes were determined via a rigorous evaluation process. Thus, the regression calibration curves for AP and MA in urine are linear within 100 approximately 50,000 ng/ml, with correlation coefficients typically exceeding 0.999. The limits of detection determined by two methods for AP and MA vary from 19 to 50 ng/ml, and limits of quantitation from 21 to 100 ng/ml. Precisions calculated for the triplicate analyses of AP and MA in a 500-ng/ml spiked control, two real-case samples and two quasi real-case samples, respectively, using regression calibration are typically below 10%. The method is simple and reliable. It may serve as an alternative to the existing confirmatory protocol for forensic urine drug testing. PMID:11499622

Wang, S M; Giang, Y S; Ling, Y C

2001-08-01

207

Plethysmography and Gas Dilution Techniques  

Microsoft Academic Search

Measurement of static lung volumes - i.e., total lung capacity (TLC), functional residual capacity, and residual volume (RV) - has undergone significant progress in its routine application in paediatrics over the last decade. In addition to providing an index of lung size and growth, many techniques are able to explore uneven ventilation and air trapping. Body plethysmography - by either

F. Marchal; C. Schweitzer

2005-01-01

208

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

209

Gamma Inert Sterilization: A Solution to Polyethylene Oxidation?  

PubMed Central

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

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

2009-01-01

210

Bino Dark Matter and Big Bang Nucleosynthesis in the Constrained E6SSM with Massless Inert Singlinos  

E-print Network

We discuss a new variant of the E6 inspired supersymmetric standard model (E6SSM) in which the two inert singlinos are exactly massless and the dark matter candidate has a dominant bino component. A successful relic density is achieved via a novel mechanism in which the bino scatters inelastically into heavier inert Higgsinos during the time of thermal freeze-out. The two massless inert singlinos contribute to the effective number of neutrino species at the time of Big Bang Nucleosynthesis, where the precise contribution depends on the mass of the Z' which keeps them in equilibrium. For example for mZ' > 1300 GeV we find Neff \\approx 3.2, where the smallness of the additional contribution is due to entropy dilution. We study a few benchmark points in the constrained E6SSM with massless inert singlinos to illustrate this new scenario.

Jonathan P. Hall; Stephen F. King

2011-04-12

211

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

NASA Astrophysics Data System (ADS)

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

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

2008-10-01

212

Carbon dioxide dilution effect on flammability limits for hydrocarbons  

Microsoft Academic Search

Theoretical models to predict the upper\\/lower flammability limits of a mixture composed of hydrocarbon and inert carbon dioxide are proposed in this study. It is found theoretically that there are linear relations between the reciprocal of the upper\\/lower flammability limits and the reciprocal of the molar fraction of hydrocarbon in the hydrocarbon\\/inert gas mixture. These theoretical linear relations are examined

Chan-Cheng Chen; Horng-Jang Liaw; Tzu-Chi Wang; Chin-Yu Lin

2009-01-01

213

Dark Matter from the Inert Doublet Model  

E-print Network

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

Laura Lopez Honorez

2007-06-01

214

The mathematics of dilution.  

PubMed

The major objection to homeopathic medicine is that the doses of medicine prescribed in some cases are too dilute for any active ingredient to be present. The medicines would hence be rendered inactive, necessitating novel explanations for the action. A further examination of dilution in the light of the Langmuir equation shows that homeopathic medicines may not be as dilute as a simplistic application of Avogadro's Principle suggests, due to surface effects. PMID:24685420

Chatterjee, Barun Kumar

2014-04-01

215

Isotope dilution analysis of polychlorinated biphenyls (PCBs) in transformer oil and global commercial PCB formulations by high resolution gas chromatography–high resolution mass spectrometry  

Microsoft Academic Search

Special polychlorinated biphenyls (PCBs) standards (native and isotope labeled) were analyzed by isotope dilution method using HRGC–HRMS. Multiple analysis of special PCBs standards by three different laboratories produced the relative response factors (RRFs) and relative standard deviations (RSDs %) was in the average of 0.979 and 3.86, respectively. Additionally, inter-laboratory analysis of various forms of transformer oil revealed the PCBs

Takumi Takasuga; Kurunthachalam Senthilkumar; Tohru Matsumura; Ken Shiozaki; Shin-ichi Sakai

2006-01-01

216

Two systems developed for purifying inert atmospheres  

NASA Technical Reports Server (NTRS)

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

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

1969-01-01

217

Passive suspensions incorporating inerters for railway vehicles  

Microsoft Academic Search

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

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

2012-01-01

218

Isotope dilution mass spectrometry  

NASA Astrophysics Data System (ADS)

In the past isotope dilution mass spectrometry (IDMS) has usually been applied using the formation of positive thermal ions of metals. Especially in calibrating other analytical methods and for the certification of standard reference materials this type of IDMS became a routine method. Today, the progress in this field lies in the determination of ultra trace amounts of elements, e.g. of heavy metals in Antarctic ice and in aerosols in remote areas down to the sub-pg g-1 and sub-pg m-3 levels respectively, in the analysis of uranium and thorium at concentrations of a few pg g-1 in sputter targets for the production of micro- electronic devices or in the determination of sub-picogram amounts of230Th in corals for geochemical age determinations and of226Ra in rock samples. During the last few years negative thermal ionization IDMS has become a frequently used method. The determination of very small amounts of selenium and technetium as well as of other transition metals such as vanadium, chromium, molybdenum and tungsten are important examples in this field. Also the measurement of silicon in connection with a re-determination of Avogadro's number and osmium analyses for geological age determinations by the Re/Os method are of special interest. Inductively-coupled plasma mass spectrometry is increasingly being used for multi-element analyses by the isotope dilution technique. Determinations of heavy metals in samples of marine origin are representative examples for this type of multi-element analysis by IDMS. Gas chromatography-mass spectrometry systems have also been successfully applied after chelation of metals (for example Pt determination in clinical samples) or for the determination of volatile element species in the environment, e.g. dimethyl sulfide. However, IDMS--specially at low concentration levels in the environment--seems likely to be one of the most powerful analytical methods for speciation in the future. This has been shown, up to now, for species of iodine, selenium and some heavy metals in aquatic systems.

Heumann, Klaus G.

1992-09-01

219

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

220

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

221

Microfluidic Serial Dilution Circuit  

PubMed Central

In vitro evolution of RNA molecules requires a method for executing many consecutive serial dilutions. To solve this problem, a microfluidic circuit has been fabricated in a three-layer glass-PDMS-glass device. The 400-nL serial dilution circuit contains five integrated membrane valves: three two-way valves arranged in a loop to drive cyclic mixing of the diluent and carryover, and two bus valves to control fluidic access to the circuit through input and output channels. By varying the valve placement in the circuit, carryover fractions from 0.04 to 0.2 were obtained. Each dilution process, which is comprised of a diluent flush cycle followed by a mixing cycle, is carried out with no pipeting, and a sample volume of 400 nL is sufficient for conducting an arbitrary number of serial dilutions. Mixing is precisely controlled by changing the cyclic pumping rate, with a minimum mixing time of 22 s. This microfluidic circuit is generally applicable for integrating automated serial dilution and sample preparation in almost any microfluidic architecture. PMID:17073422

Paegel, Brian M.; Grover, William H.; Skelley, Alison M.; Mathies, Richard A.; Joyce, Gerald F.

2008-01-01

222

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

NASA Technical Reports Server (NTRS)

The reactivity of the fullerenes is primarily a function of their strain, as measured by the pyramidalization angle or curvature of the conjugated carbon atoms. The development of faceting in the structure of large icosahedral fullerenes leads to a minimum in the value of the maximum fullerene pyramidalization angle that lies in the vicinity of C-240. On this basis it is argued that C-240 will be the most chemically inert fullerene. This observation explains the production of [10,10] single-walled nanotubes because a C-240 hemisphere is required for the nucleation of such tubes.

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

1997-01-01

223

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

224

The effect of internal particle heat conduction on heat transfer analysis of turbulent gas–particle flow in a dilute state  

Microsoft Academic Search

In many cases the conduction mechanism inside a particle can not be ignored (large particles, low thermal conductivity and\\u000a high porosity) during turbulent gas–particle flows. However, the accurate solution might be difficult to apply. Therefore,\\u000a we first develop here the ability to conduct accurate solution and then we define the criterion for which the internal conductivity\\u000a might be ignored. A

Mordechai Haim; Haim Kalman

2008-01-01

225

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

2006-10-01

226

Helium dilution refrigeration system  

DOEpatents

A helium dilution refrigeration system operable over a limited time period, and recyclable for a next period of operation is disclosed. The refrigeration system is compact with a self-contained pumping system and heaters for operation of the system. A mixing chamber contains [sup 3]He and [sup 4]He liquids which are precooled by a coupled container containing [sup 3]He liquid, enabling the phase separation of a [sup 3]He rich liquid phase from a dilute [sup 3]He-[sup 4]He liquid phase which leads to the final stage of a dilution cooling process for obtaining low temperatures. The mixing chamber and a still are coupled by a fluid line and are maintained at substantially the same level with the still cross sectional area being smaller than that of the mixing chamber. This configuration provides maximum cooling power and efficiency by the cooling period ending when the [sup 3]He liquid is depleted from the mixing chamber with the mixing chamber nearly empty of liquid helium, thus avoiding unnecessary and inefficient cooling of a large amount of the dilute [sup 3]He-[sup 4]He liquid phase. 2 figs.

Roach, P.R.; Gray, K.E.

1988-09-13

227

Helium dilution refrigeration system  

DOEpatents

A helium dilution refrigeration system operable over a limited time period, and recyclable for a next period of operation. The refrigeration system is compact with a self-contained pumping system and heaters for operation of the system. A mixing chamber contains .sup.3 He and .sup.4 He liquids which are precooled by a coupled container containing .sup.3 He liquid, enabling the phase separation of a .sup.3 He rich liquid phase from a dilute .sup.3 He-.sup.4 He liquid phase which leads to the final stage of a dilution cooling process for obtaining low temperatures. The mixing chamber and a still are coupled by a fluid line and are maintained at substantially the same level with the still cross sectional area being smaller than that of the mixing chamber. This configuration provides maximum cooling power and efficiency by the cooling period ending when the .sup.3 He liquid is depleted from the mixing chamber with the mixing chamber nearly empty of liquid helium, thus avoiding unnecessary and inefficient cooling of a large amount of the dilute .sup.3 He-.sup.4 He liquid phase.

Roach, Patrick R. (Darien, IL); Gray, Kenneth E. (Naperville, IL)

1988-01-01

228

40 CFR 89.419 - Dilute gaseous exhaust sampling and analytical system description.  

Code of Federal Regulations, 2012 CFR

...HFID. These gas temperatures...free from the influence of any wakes...Increase the gas stream temperature to...diluted exhaust stream inside of the...free from the influences of any wakes...C. Sample gas temperature...

2012-07-01

229

40 CFR 89.419 - Dilute gaseous exhaust sampling and analytical system description.  

...HFID. These gas temperatures...free from the influence of any wakes...Increase the gas stream temperature to...diluted exhaust stream inside of the...free from the influences of any wakes...C. Sample gas temperature...

2014-07-01

230

Photon energy dependence of final state screening in a dilute electron gas system: A synchrotron radiation photoemission study of β-PbO2  

NASA Astrophysics Data System (ADS)

Photoemission spectra of thick films of ?-PbO 2 have been measured over a range of exciting photon energies between 40 eV and 150 eV. There is evidence for occupation of conduction band states above the top of the main valence band to give a degenerate electron gas and the spectra terminate in a sharp metallic Fermi edge. Structure associated with screening of shallow 5d core holes by the mobile conduction electrons observed in Al K? excited X-ray photoemission spectra is suppressed in the lower energy spectra and the Pb 5d core level appears as a simple spin-orbit doublet.

Payne, D. J.; Hu, J. P.; Egdell, R. G.; Dhanak, V. R.; Miller, G.

2007-07-01

231

A compact rotating dilution refrigerator.  

PubMed

We describe the design and performance of a new rotating dilution refrigerator that will primarily be used for investigating the dynamics of quantized vortices in superfluid (4)He. All equipment required to operate the refrigerator and perform experimental measurements is mounted on two synchronously driven, but mechanically decoupled, rotating carousels. The design allows for relative simplicity of operation and maintenance and occupies a minimal amount of space in the laboratory. Only two connections between the laboratory and rotating frames are required for the transmission of electrical power and helium gas recovery. Measurements on the stability of rotation show that rotation is smooth to around 10(-3) rad s(-1) up to angular velocities in excess of 2.5 rad s(-1). The behavior of a high-Q mechanical resonator during rapid changes in rotation has also been investigated. PMID:24182127

Fear, M J; Walmsley, P M; Chorlton, D A; Zmeev, D E; Gillott, S J; Sellers, M C; Richardson, P P; Agrawal, H; Batey, G; Golov, A I

2013-10-01

232

A compact rotating dilution refrigerator  

NASA Astrophysics Data System (ADS)

We describe the design and performance of a new rotating dilution refrigerator that will primarily be used for investigating the dynamics of quantized vortices in superfluid 4He. All equipment required to operate the refrigerator and perform experimental measurements is mounted on two synchronously driven, but mechanically decoupled, rotating carousels. The design allows for relative simplicity of operation and maintenance and occupies a minimal amount of space in the laboratory. Only two connections between the laboratory and rotating frames are required for the transmission of electrical power and helium gas recovery. Measurements on the stability of rotation show that rotation is smooth to around 10-3 rad s-1 up to angular velocities in excess of 2.5 rad s-1. The behavior of a high-Q mechanical resonator during rapid changes in rotation has also been investigated.

Fear, M. J.; Walmsley, P. M.; Chorlton, D. A.; Zmeev, D. E.; Gillott, S. J.; Sellers, M. C.; Richardson, P. P.; Agrawal, H.; Batey, G.; Golov, A. I.

2013-10-01

233

Polarization rotation for light propagating non-parallel to a magnetic field in QED vacuum and in a dilute electron gas  

E-print Network

The rotation of the polarization vector for light propagating perpendicular to an external constant external magnetic field $B$, is calculated in quantum vacuum, where it leads to different photon eigenmodes of the magnetized photon self-energy tensor for polarizations along and orthogonal to $B$ (Cotton-Mouton effect in QED vacuum). Its analogies and differences with Faraday effect are discussed and both phenomena are calculated for a relativistic electron gas at low densities, by starting from the low energy limit of the photon self-energy eigenvalues in presence of $B$. In the Cotton-Mouton case the polarization vector describes an ellipse whose axes vary periodically from zero to a maximum value. By assuming an effective electron density of order $10^3$ cm$^{-3}$ the quantum relativistic eigenvalues lead to a rotation of the polarization plane compatible with some of the limit values reported by PVLAS experiments. Other consequences, which are interesting for astrophysics, are also discussed.

H. Perez Rojas; E. Rodriguez Querts

2007-08-16

234

Mucosal vaccination against tuberculosis using inert bioparticles.  

PubMed

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

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

2013-11-01

235

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

236

Continuous distributions of specific ventilation recovered from inert gas washout  

NASA Technical Reports Server (NTRS)

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

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

1978-01-01

237

Inert gas test of two 12-cm magnetostatic thrusters  

NASA Technical Reports Server (NTRS)

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

Ramsey, W. D.

1982-01-01

238

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; Sánchez-Brunete, Consuelo; Miguel, Esther; Pérez, Rosa A; Tadeo, José L

2013-03-29

239

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

Microsoft Academic Search

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

Rodney C. Ewing; Lumin Wang

2002-01-01

240

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

241

Spin currents in diluted magnetic semiconductors.  

PubMed

We study zero-bias spin separation in (Cd,Mn)Te/(Cd,Mg)Te diluted magnetic semiconductor structures. The spin current generated by electron gas heating under terahertz radiation is converted into a net electric current by applying an external magnetic field. The experiments show that the spin polarization of the magnetic ion system enhances drastically the conversion process due to giant Zeeman splitting of the conduction band and spin-dependent electron scattering on localized Mn(2+) ions. PMID:19518662

Ganichev, S D; Tarasenko, S A; Bel'kov, V V; Olbrich, P; Eder, W; Yakovlev, D R; Kolkovsky, V; Zaleszczyk, W; Karczewski, G; Wojtowicz, T; Weiss, D

2009-04-17

242

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

243

Diluted magnetic oxides  

NASA Astrophysics Data System (ADS)

In this review, we review the progress of research on ZnO- and In2O3-based diluted magnetic oxides (DMOs). Firstly, we present the preparation and characterization of DMOs. The former includes the preparation methods and conditions, and the latter includes the characterization techniques for measuring microstructures. Secondly, we introduce the magnetic and transport properties of DMOs, as well as the relationship between them. Thirdly, the origin and mechanism of the ferromagnetism are discussed. Fourthly, we introduce other related work, including computational work and pertinent heterogeneous structures, such as multilayers and magnetic tunnel junctions. Finally, we provide an overview and outlook for DMOs.

Li, XiaoLi; Qi, ShiFei; Jiang, FengXian; Quan, ZhiYong; Xu, XiaoHong

2013-01-01

244

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

245

He dilution refrigerator  

NASA Astrophysics Data System (ADS)

We describe the preparation of ultracold atomic clouds in a dilution refrigerator. The closed-cycle 3He/4He cryostat was custom made to provide optical access for laser cooling, optical manipulation and detection of atoms. We show that the cryostat meets the requirements for cold atom experiments, specifically in terms of operating a magneto-optical trap, magnetic traps and magnetic transport under ultrahigh vacuum conditions. The presented system is a step toward the creation of a quantum hybrid system combining ultracold atoms and solid-state quantum devices.

Jessen, F.; Knufinke, M.; Bell, S. C.; Vergien, P.; Hattermann, H.; Weiss, P.; Rudolph, M.; Reinschmidt, M.; Meyer, K.; Gaber, T.; Cano, D.; Günther, A.; Bernon, S.; Koelle, D.; Kleiner, R.; Fortágh, J.

2014-09-01

246

Effects of helium dilution on glow discharge depositions of aSi 1-xGex:H alloys  

Microsoft Academic Search

A study is made of the effects of helium feed gas dilution on the properties of a-Si1-xGex:H alloys deposited using radio-frequency glow discharge decomposition of silane and germane gas mixtures. Comparing a-Si1-xGex:H films deposited using 65% helium dilution with films deposited using 65% hydrogen dilution, it is found that films deposited with helium dilution have a longer charge carrier diffusion

Y. S. Tsuo; Y. Xu; I. Balberg; R. S. Crandall

1991-01-01

247

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

248

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

249

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

250

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

251

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

NASA Technical Reports Server (NTRS)

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

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

1995-01-01

252

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

Microsoft Academic Search

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

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

2011-01-01

253

Dilution jet mixing program  

NASA Technical Reports Server (NTRS)

Parametric tests were conducted to quantify the mixing of opposed rows of jets (two-sided injection) in a confined cross flow. Results show that jet penetrations for two sided injections are less than that for single-sided injections, but the jet spreading rates are faster for a given momentum ratio and orifice plate. Flow area convergence generally enhances mixing. Mixing characteristics with asymmetric and symmetric convergence are similar. For constant momentum ratio, the optimum S/H(0) with in-line injections is one half the optimum value for single sided injections. For staggered injections, the optimum S/H(0) is twice the optimum value for single-sided injection. The correlations developed predicted the temperature distributions within first order accuracy and provide a useful tool for predicting jet trajectory and temperature profiles in the dilution zone with two-sided injections.

Srinivasan, R.; Coleman, E.; Johnson, K.

1984-01-01

254

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

SciTech Connect

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

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

1990-05-01

255

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

256

Gas shielding apparatus  

DOEpatents

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

Brandt, D.

1984-06-05

257

Gas shielding apparatus  

DOEpatents

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

Brandt, Daniel (Los Alamos, NM)

1985-01-01

258

Gas shielding apparatus  

DOEpatents

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

Brandt, D.

1985-12-31

259

Stress in dilute suspensions  

NASA Technical Reports Server (NTRS)

Generally, two types of theory are used to describe the field equations for suspensions. The so-called postulated equations are based on the kinetic theory of mixtures, which logically should give reasonable equations for solutions. The basis for the use of such theory for suspensions is tenuous, though it at least gives a logical path for mathematical arguments. It has the disadvantage that it leads to a system of equations which is underdetermined, in a sense that can be made precise. On the other hand, the so-called averaging theory starts with a determined system, but the very process of averaging renders the resulting system underdetermined. A third type of theory is proposed in which the kinetic theory of gases is used to motivate continuum equations for the suspended particles. This entails an interpretation of the stress in the particles that is different from the usual one. Classical theory is used to describe the motion of the suspending medium. The result is a determined system for a dilute suspension. Extension of the theory to more concentrated systems is discussed.

Passman, Stephen L.

1989-01-01

260

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

Microsoft Academic Search

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

I.K. Puri; K. Seshadri

1986-01-01

261

THE ANISOTROPIC TRANSPORT EFFECTS ON DILUTE PLASMAS  

SciTech Connect

We examine the linear stability analysis of a hot, dilute, and differentially rotating plasma by considering anisotropic transport effects. In dilute plasmas, the ion Larmor radius is small compared with its collisional mean free path. In this case, the transport of heat and momentum along the magnetic field lines becomes important. This paper presents a novel linear instability that may be more powerful and greater than ideal magnetothermal instability and ideal magnetorotational instability in the dilute astrophysical plasmas. This type of plasma is believed to be found in the intracluster medium (ICM) of galaxy clusters and radiatively ineffective accretion flows around black holes. We derive the dispersion relation of this instability and obtain the instability condition. There is at least one unstable mode that is independent of the temperature gradient direction for a helical magnetic field geometry. This novel instability is driven by the gyroviscosity coupled with differential rotation. Therefore, we call it gyroviscous-modified magnetorotational instability (GvMRI). We examine how the instability depends on signs of the temperature gradient and the gyroviscosity and also on the magnitude of the thermal frequency and on the values of the pitch angle. We provide a detailed physical interpretation of the obtained results. The GvMRI is applicable not only to the accretion flows and ICM but also to the transition region between cool dense gas and the hot low-density plasma in stellar coronae, accretion disks, and the multiphase interstellar medium because it is independent of the temperature gradient direction.

Devlen, Ebru, E-mail: ebru.devlen@ege.edu.tr [Department of Astronomy and Space Sciences, Faculty of Science, University of Ege, Bornova 35100, Izmir (Turkey)

2011-04-20

262

Dilution refrigeration for space applications  

NASA Technical Reports Server (NTRS)

Dilution refrigerators are presently used routinely in ground based applications where temperatures below 0.3 K are required. The operation of a conventional dilution refrigerator depends critically on the presence of gravity. To operate a dilution refrigerator in space many technical difficulties must be overcome. Some of the anticipated difficulties are identified in this paper and possible solutions are described. A single cycle refrigerator is described conceptually that uses forces other than gravity to function and the stringent constraints imposed on the design by requiring the refrigerator to function on the earth without using gravity are elaborated upon.

Israelsson, U. E.; Petrac, D.

1990-01-01

263

Zirconia-magnesia inert matrix fuel and waste form: Synthesis, characterization and chemical performance in an advanced fuel cycle  

NASA Astrophysics Data System (ADS)

There is a significant buildup in plutonium stockpiles throughout the world, because of spent nuclear fuel and the dismantling of weapons. The radiotoxicity of this material and proliferation risk has led to a desire for destroying excess plutonium. To do this effectively, it must be fissioned in a reactor as part of a uranium free fuel to eliminate the generation of more plutonium. This requires an inert matrix to volumetrically dilute the fissile plutonium. Zirconia-magnesia dual phase ceramic has been demonstrated to be a favorable material for this task. It is neutron transparent, zirconia is chemically robust, magnesia has good thermal conductivity and the ceramic has been calculated to conform to current economic and safety standards. This dissertation contributes to the knowledge of zirconia-magnesia as an inert matrix fuel to establish behavior of the material containing a fissile component. First, the zirconia-magnesia inert matrix is synthesized in a dual phase ceramic containing a fissile component and a burnable poison. The chemical constitution of the ceramic is then determined. Next, the material performance is assessed under conditions relevant to an advanced fuel cycle. Reactor conditions were assessed with high temperature, high pressure water. Various acid solutions were used in an effort to dissolve the material for reprocessing. The ceramic was also tested as a waste form under environmental conditions, should it go directly to a repository as a spent fuel. The applicability of zirconia-magnesia as an inert matrix fuel and waste form was tested and found to be a promising material for such applications.

Holliday, Kiel Steven

264

DAVINCI: Dilute Aperture VIsible Nulling Coronagraphic Imager  

NASA Technical Reports Server (NTRS)

This slide presentation gives an overview of DAVINCI (Dilute Aperture VIsible Nulling Coronagraphic Imager). The presentation also includes information about dilute aperture coronagraph, and lyot efficiency.

Shao, Michael; Levine, B. M.; Vasisht, G.; Lane, B. F.; Woodruff, R.; Vasudevan, G.; Samuele, R.; Lloyd, C. A.; Clampin, M.; Lyon, R.; Guyon, O.

2008-01-01

265

"Inert" Strengths of Silicon Nitride Ceramics at Elevated Temperatures  

NASA Technical Reports Server (NTRS)

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

Choi, Sung R.; Salem, Jonathan A.

1996-01-01

266

The Influence of Charge Dilution and Injection Timing on Low Temperature Diesel Combustion and Emissions  

Microsoft Academic Search

The effects of charge dilution on low-temperature diesel combustion and emissions were investigated in a small- bore single-cylinder diesel engine over a wide range of injection timing. The fresh air was diluted with additional N2 and CO2, simulating 0 to 65% exhaust gas recirculation in an engine. Diluting the intake charge lowers the flame temperature T due to the reactant

Sanghoon Kook; Choongsik Bae

267

Effect of H 2 dilution on Cat-CVD aSiC:H films  

Microsoft Academic Search

Effect of hydrogen (H2) dilution of the Silane (SiH4), acetylene (C2H2) gas mixture during the deposition of hydrogenated amorphous silicon carbon alloy (a-SiC:H) films by Cat-CVD process shows that the H2 dilution induced additional carbon incorporation, leading to an increase of the carbon content in the films from 52% to 70% for the maximum H2 dilution employed. A slight increase

Bibhu P. Swain; T. K. Gundu Rao; Mainak Roy; Jagannath Gupta; R. O. Dusane

2006-01-01

268

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...

269

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

270

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

271

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

272

Bicosomes: bicelles in dilute systems.  

PubMed

Bicelles are discoidal phospholipid nanostructures at high lipid concentrations. Under dilute conditions, bicelles become larger and adopt a variety of morphologies. This work proposes a strategy to preserve the discoidal morphology of bicelles in environments with high water content. Bicelles were formed in concentrated conditions and subsequently encapsulated in liposomes. Later dilution of these new structures, called bicosomes, demonstrated that lipid vesicles were able to isolate and protect bicelles entrapped inside them from the medium. Characterization of systems before and after dilution by dynamic light-scattering spectroscopy and cryo-transmission electron microscopy showed that free bicelles changed in size and morphology, whereas encapsulated bicelles remained unaltered by the effect of dilution. Free and entrapped bicelles (containing the paramagnetic contrast agent gadodiamide) were injected into rat brain lateral ventricles. Coronal and sagittal visualization was performed by magnetic resonance imaging. Whereas rats injected with free bicelles did not survive the surgery, those injected with bicosomes did, and a hyperintensity effect due to gadodiamide was observed in the cerebrospinal fluid. These results indicate that bicosomes are a good means of preserving the morphology of bicelles under dilution conditions. PMID:20643066

Rodríguez, Gelen; Soria, Guadalupe; Coll, Elisenda; Rubio, Laia; Barbosa-Barros, Lucyanna; López-Iglesias, Carmen; Planas, Anna M; Estelrich, Joan; de la Maza, Alfons; López, Olga

2010-07-21

273

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

274

What are Inert Ingredients?1 Frederick M. Fishel2  

E-print Network

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

Watson, Craig A.

275

Porous HMX initiation studies-sugar as an inert simulant  

Microsoft Academic Search

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

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

1998-01-01

276

Porous HMX initiation studies -- Sugar as an inert simulant  

Microsoft Academic Search

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

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

1997-01-01

277

Porous HMX initiation studies—sugar as an inert simulant  

Microsoft Academic Search

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

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

1998-01-01

278

Porous HMX Initiation Studies =96 Sugar as an Inert Simulant  

Microsoft Academic Search

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

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

1997-01-01

279

Contamination control in semiconductor industry using laminar barrier inerting technology  

Microsoft Academic Search

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

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

1994-01-01

280

Dark Matter with Two Inert Doublets plus One Higgs Doublet  

E-print Network

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

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

2014-07-29

281

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

282

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...

283

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

2012-04-17

284

Primary system boron dilution analysis  

Microsoft Academic Search

The results are presented for an analysis conducted to determine the potential paths through which nonborated water or water with insufficient boron concentration might enter the LOFT primary coolant piping system or reactor vessel to cause dilution of the borated primary coolant water. No attempt was made in the course of this analysis to identify possible design modifications nor to

R. J. Crump; C. J. Naretto; R. A. Borgen; H. C. Rockhold

1978-01-01

285

Resource Dilution or Resource Augmentation?  

E-print Network

Resource Dilution or Resource Augmentation? Number of Siblings, Birth Order, Sex of the Child Augmentation? Number of Siblings, Birth Order, Sex of the Child and Frequency of Mother's Activities" This project extends research on the genesis and effects of individual heterogeneity to cover psychological

Moeller, Ralf

286

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

287

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

Code of Federal Regulations, 2010 CFR

...air and diluted exhaust flow meters. 1065.240...AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES...Measurement Instruments Flow-Related Measurements § 1065.240 Dilution air and diluted exhaust...

2010-07-01

288

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

Code of Federal Regulations, 2013 CFR

...air and diluted exhaust flow meters. 1065.240...AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES...Measurement Instruments Flow-Related Measurements § 1065.240 Dilution air and diluted exhaust...

2013-07-01

289

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

Code of Federal Regulations, 2011 CFR

...air and diluted exhaust flow meters. 1065.240...AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES...Measurement Instruments Flow-Related Measurements § 1065.240 Dilution air and diluted exhaust...

2011-07-01

290

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

Code of Federal Regulations, 2012 CFR

...air and diluted exhaust flow meters. 1065.240...AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES...Measurement Instruments Flow-Related Measurements § 1065.240 Dilution air and diluted exhaust...

2012-07-01

291

Vapor-liquid equilibrium constants at infinite dilution determined by a gas stripping method: ethane, propane, n-butane, n-pentane in the methane-n-decane system  

Microsoft Academic Search

A new apparatus to measure partition coefficients Kinfinity \\/SUB s\\/ at infinite dilution up to 200 10⁵ Pa and 423 K is described. Measurements of the systems: (1) methane-ethane-n-decane and methane-propane-n-decane at 294.25 K; and (2) methane-n-butane-n-decane at 344.25 K illustrate the reproducibility and good agreement with literature data. In addition, new data were obtained for the system methane-npentane-n-decane at

D. Legret; J. Desteve; H. Renon; D. Richon

1983-01-01

292

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

PubMed

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

Chandrasekaran, Sriraam R; Hopke, Philip K

2012-12-01

293

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

NASA Astrophysics Data System (ADS)

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

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

2011-06-01

294

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

Microsoft Academic Search

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

Rajarshi Banerjee; Ramesh Chandra; Pushan Ayyub

2002-01-01

295

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

296

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

SciTech Connect

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

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

2000-02-29

297

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

298

Evolution of weak disturbances in inert binary mixtures  

NASA Technical Reports Server (NTRS)

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

Rasmussen, M. L.

1977-01-01

299

Inert supports for lactic acid fermentation —a technological assessment  

Microsoft Academic Search

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

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

1992-01-01

300

A new viable region of the inert doublet model  

SciTech Connect

The inert doublet model, a minimal extension of the Standard Model by a second Higgs doublet, is one of the simplest and most attractive scenarios that can explain the dark matter. In this paper, we demonstrate the existence of a new viable region of the inert doublet model featuring dark matter masses between M{sub W} and about 160 GeV. Along this previously overlooked region of the parameter space, the correct relic density is obtained thanks to cancellations between different diagrams contributing to dark matter annihilation into gauge bosons (W{sup +}W{sup ?} and Z{sup 0}Z{sup 0}). First, we explain how these cancellations come about and show several examples illustrating the effect of the parameters of the model on the cancellations themselves and on the predicted relic density. Then, we perform a full scan of the new viable region and analyze it in detail by projecting it onto several two-dimensional planes. Finally, the prospects for the direct and the indirect detection of inert Higgs dark matter within this new viable region are studied. We find that present direct detection bounds already rule out a fraction of the new parameter space and that future direct detection experiments, such as Xenon100, will easily probe the remaining part in its entirety.

Honorez, Laura Lopez [Service de Physique Théorique, Université Libre de Bruxelles, 1050 Brussels (Belgium); Yaguna, Carlos E., E-mail: carlos.yaguna@uam.es, E-mail: llopezho@ulb.ac.be [Departamento de Física Teórica C-XI and Instituto de Física Teórica UAM-CSIC, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid (Spain)

2011-01-01

301

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

302

Gas stream purifier  

NASA Technical Reports Server (NTRS)

A gas stream purifier has been developed that is capable of removing corrosive acid, base, solvent, organic, inorganic, and water vapors as well as particulates from an inert mixed gas stream using only solid scrubbing agents. This small, lightweight purifier has demonstrated the ability to remove contaminants from an inert gas stream with a greater than 99 percent removal efficiency. The Gas Stream Purifier has outstanding market and sales potential in manufacturing, laboratory and science industries, medical, automotive, or any commercial industry where pollution, contamination, or gas stream purification is a concern. The purifier was developed under NASA contract NAS9-18200 Schedule A for use in the international Space Station. A patent application for the Gas Stream Purifier is currently on file with the United States Patent and Trademark Office.

Adam, Steven J.

1994-01-01

303

Numerical Investigation of Fuel Dilution Effects on the Performance of the Conventional and the Highly Preheated and Diluted Air Combustion Furnaces  

Microsoft Academic Search

This numerical study investigates the effects of using a diluted fuel (50% natural gas and 50% N2) in an industrial furnace under several cases of conventional combustion (air with 21% O2 at 300 and 1273 K) and the highly preheated and diluted air (1273 K with 10% O2 and 90% N2) combustion (HPDAC) conditions using an in-house computer program. It

Kiomars Abbasi Khazaei; Ali Asghar Hamidi; Masoud Rahimi

2009-01-01

304

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

305

Detailed Studies on Flame Extinction by Inert Particles in Normal- and Micro-gravity  

NASA Technical Reports Server (NTRS)

The combustion of dusty flows has been studied to lesser extent than pure gas phase flows and sprays. Particles can have a strong effect by modifying the dynamic response and detailed structure of flames through the dynamic, thermal, and chemical couplings between the two phases. A rigorous understanding of the dynamics and structure of two-phase flows can be attained in stagnation flow configurations, which have been used by others to study spray combustion as well as reacting dusty flows. In earlier studies on reacting dusty flows, the thermal coupling between the two phases as well as the effect of gravity on the flame response were not considered. However, in Ref. 6, the thermal coupling between chemically inert particles and the gas was addressed in premixed flames. The effects of gravity was also studied showing that it can substantially affect the profiles of the particle velocity, number density, mass flux, and temperature. The results showed a strong dynamic and thermal dependence of reacting dusty flows to particle number density. However, the work was only numerical and limited to twin-flames, stagnation, premixed flames. In Ref. 7 the effects of chemically inert particle clouds on the extinction of strained premixed and non-premixed flames were studied both experimentally and numerically at 1-g. It was shown and explained that large particles can cause more effective flame cooling compared to smaller particles. The effects of flame configuration and particle injection orientation were also addressed. The complexity of the coupling between the various parameters in such flows was demonstrated and it was shown that it was impossible to obtain a simple and still meaningful scaling that captured all the pertinent physics.

Andac, M. G.; Egolfopoulos, F. N.; Campbell, C. S.

2001-01-01

306

Effect of swine manure dilution on ammonia, hydrogen sulfide, carbon dioxide, and sulfur dioxide releases.  

PubMed

Animal manure is a significant source of environmental pollution and manure dilution in barn cleaning and slurry storage is a common practice in animal agriculture. The effect of swine manure dilution on releases of four pollutant gases was studied in a 30-day experiment using eight manure reactors divided into two groups. One group was treated with swine manure of 6.71% dry matter and another with manure diluted with water to 3.73% dry matter. Ammonia release from the diluted manure was 3.32 mg min(-1)m(-2) and was 71.0% of the 4.67 mg min(-1)m(-2) from the undiluted manure (P<0.01). Because the ammonia release reduction ratio was lower than the manure dilution ratio, dilution could increase the total ammonia emissions from swine manure, especially in lagoons with large liquid surface areas. Carbon dioxide release of 87.3 mg min(-1)m(-2) from the diluted manure was 56.4% of the 154.8 mg min(-1)m(-2) from the undiluted manure (P<0.01). Manure dry matter was an important factor for carbon dioxide release from manure. No differences were observed between the treatments (P>0.05) for both hydrogen sulfide and sulfur dioxide releases. Therefore, dilution could also significantly increase the total releases of hydrogen sulfide and sulfur dioxide to the environment because dilution adds to the total manure volume and usually also increases the total gas release surface area. PMID:20850169

Ni, Ji-Qin; Heber, Albert J; Sutton, Alan L; Kelly, Dan T; Patterson, John A; Kim, Sun-Tae

2010-11-01

307

Experimental research of the effect of hydrogen in argon as a shielding gas in arc welding of high-alloy stainless steel  

Microsoft Academic Search

The paper treats the effect of hydrogen in argon as a shielding gas in arc welding of austenitic stainless steel. The studies were carried out in TIG (Tungsten Inert Gas) welding with a non-consumable electrode and MIG (Metal Inert Gas) welding with a consumable electrode, in both cases with different volume additions of hydrogen to the argon shielding gas, i.e.,

M. Suban

2000-01-01

308

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

309

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

310

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

311

Inert scalar dark matter in an extra dimension inspired model  

NASA Astrophysics Data System (ADS)

In this paper we analyze a dark matter model inspired by theories with extra dimensions. The dark matter candidate corresponds to the first Kaluza–Klein mode of an real scalar added to the Standard Model. The tower of new particles enriches the calculation of the relic abundance. For large mass splitting, the model converges to the predictions of the inert singlet dark matter model. For nearly degenerate mass spectrum, coannihilations increase the cross-sections used for direct and indirect dark matter searches. Moreover, the Kaluza–Klein zero mode can mix with the SM higgs and further constraints can be applied.

Lineros, R. A.; Pereira dos Santos, F. A.

2014-10-01

312

Inert scalar dark matter in an extra dimension inspired model  

E-print Network

In this paper we analyze a dark matter model inspired by theories with extra dimensions. The dark matter candidate corresponds to the first Kaluza-Klein mode of a real scalar added to the Standard Model. The tower of new particles enriches the calculation of the relic abundance. For large mass splitting, the model converges to the predictions of the inert singlet dark matter model. For nearly degenerate mass spectrum, coannihilations increase the cross-sections used for direct and indirect dark matter searches. Moreover, the Kaluza-Klein zero mode can mix with the SM higgs and further constraints can be applied.

R. A. Lineros; F. A. Pereira dos Santos

2014-07-22

313

Polyvinyl alcohol battery separator containing inert filler. [alkaline batteries  

NASA Technical Reports Server (NTRS)

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 enhances 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. (inventors)

1981-01-01

314

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

NASA Technical Reports Server (NTRS)

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

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

1999-01-01

315

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

NASA Technical Reports Server (NTRS)

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

Egolfopoulos, Fokion N.; Campbell, Charles S.

1999-01-01

316

Serial Dilution & Parts Per Million  

NSDL National Science Digital Library

This activity provides a real world application of the ATEEC Recommended Core Curriculum. This curriculum was identified by ATEEC Fellows as necessary preparation for environmental technology occupation. In this activity, students will experiment with serial dilution and parts per million. At the end of the activity, students will understand how to perform lab procedures, translate real world problems into math relationship, apply ratios and proportions to solve problems, manipulate and substitute variables to solve formulas, and demonstrate safe practices. The activity is appropriate for a high school biology or chemistry class.

2013-11-04

317

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

318

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

319

Dilute Oxygen Combustion Phase 2 Final Report  

SciTech Connect

A novel burner, in which fuel (natural gas) and oxidant (oxygen or air) are separately injected into a furnace, shows promise for achieving very low nitrogen oxide(s) (NOx) emissions for commercial furnace applications. The dilute oxygen combustion (DOC) burner achieves very low NOx through in-furnace dilution of the oxidant stream prior to combustion, resulting in low flame temperatures, thus inhibiting thermal NOx production. The results of a fundamental and applied research effort on the development of the DOC burner are presented. In addition, the results of a market survey detailing the potential commercial impact of the DOC system are disclosed. The fundamental aspects of the burner development project involved examining the flame characteristics of a natural gas turbulent jet in a high-temperature (~1366 K) oxidant (7-27% O2 vol. wet). Specifically, the mass entrainment rate, the flame lift-off height, the velocity field and major species field of the jet were evaluated as a function of surrounding-gas temperature and composition. The measured entrainment rate of the fuel jet decreased with increasing oxygen content in the surrounding high-temperature oxidant, and was well represented by the d+ scaling correlation found in the literature. The measured flame lift-off height decreased with increasing oxygen content and increasing temperature of the surrounding gas. An increase in surrounding-gas oxygen content and/or temperature inhibited the velocity decay within the jet periphery as a function of axial distance as compared to isothermal turbulent jets. However, the velocity measurements were only broadly represented by the d+ scaling correlation. Several DOC burner configurations were tested in a laboratory-scale furnace at a nominal firing rate of 185 kW (~0.63 MMBtu/h). The flue gas composition was recorded as a function of furnace nitrogen content, furnace temperature, burner geometric arrangement, firing rate, and fuel injection velocity. NOx emissions increased with increasing furnace nitrogen content and furnace temperature, but remained relatively insensitive to variations in fuel injection velocity and firing rate. NOx emissions below 5-10-3 g/MJ (10 ppm-air equivalent at 3% O2 dry) were obtained for furnace temperatures below 1533 K (2300?F) and furnace nitrogen levels between 1 and 40%. CO emissions were typically low (<35 ppm). Detailed in-furnace species measurements revealed the importance of the interior furnace circulation patterns, as influenced by fuel and oxidant injection schemes, on pollutant emissions. The combustion stability traits of several DOC burner arrangements were ascertained through furnace pressure measurements, wit6h increased stability occurring as furnace temperature increased and as the separation distance between fuel and oxidant inputs decreased. Based on current market conditions, oxy-fuel conversion of batch steel reheat furnaces with a DOC burner is justified on the basis of lower utility costs alone. However, conversion of continuous steel reheat furnaces, which are responsible for most steel production, required additional economic incentives, such as further fuel savings, increased furnace productivity, or emission credits.

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

2005-09-30

320

Dilute Oxygen Combustion Phase I Final Report  

SciTech Connect

A novel burner, in which fuel (natural gas) and oxidant (oxygen or air) are separately injected into a furnace, shows promise for achieving very low nitrogen oxide(s) (NOx) emissions for commercial furnace applications. The dilute oxygen combustion (DOC) burner achieves very low NOx through in-furnace dilution of the oxidant stream prior to combustion, resulting in low flame temperatures, thus inhibiting thermal NOx production. The results of a fundamental and applied research effort on the development of the DOC burner are presented. In addition, the results of a market survey detailing the potential commercial impact of the DOC system are disclosed. The fundamental aspects of the burner development project involved examining the flame characteristics of a natural gas turbulent jet in a high-temperature (~1366 K) oxidant (7-27% O2 vol. wet). Specifically, the mass entrainment rate, the flame lift-off height, the velocity field and major species field of the jet were evaluated as a function of surrounding-gas temperature and composition. The measured entrainment rate of the fuel jet decreased with increasing oxygen content in the surrounding high-temperature oxidant, and was well represented by the d+ scaling correlation found in the literature. The measured flame lift-off height decreased with increasing oxygen content and increasing temperature of the surrounding gas. An increase in surrounding-gas oxygen content and/or temperature inhibited the velocity decay within the jet periphery as a function of axial distance as compared to isothermal turbulent jets. However, the velocity measurements were only broadly represented by the d+ scaling correlation. Several DOC burner configurations were tested in a laboratory-scale furnace at a nominal firing rate of 185 kW (~0.63 MMBtu/h). The flue gas composition was recorded as a function of furnace nitrogen content, furnace temperature, burner geometric arrangement, firing rate, and fuel injection velocity. NOx emissions increased with increasing furnace nitrogen content and furnace temperature, but remained relatively insensitive to variations in fuel injection velocity and firing rate. NOx emissions below 5-10-3 g/MJ (10 ppm-air equivalent at 3% O2 dry) were obtained for furnace temperatures below 1533 K (2300°F) and furnace nitrogen levels between 1 and 40%. CO emissions were typically low (<35 ppm). Detailed in-furnace species measurements revealed the importance of the interior furnace circulation patterns, as influenced by fuel and oxidant injection schemes, on pollutant emissions. The combustion stability traits of several DOC burner arrangements were ascertained through furnace pressure measurements, wit6h increased stability occurring as furnace temperature increased and as the separation distance between fuel and oxidant inputs decreased. Based on current market conditions, oxy-fuel conversion of batch steel reheat furnaces with a DOC burner is justified on the basis of lower utility costs alone. However, conversion of continuous steel reheat furnaces, which are responsible for most steel production, required additional economic incentives, such as further fuel savings, increased furnace productivity, or emission credits.

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

1997-10-31

321

Dilute oxygen combustion. Phase I report  

SciTech Connect

A novel burner, in which fuel (natural gas) and oxidant (oxygen or air) are separately injected into a furnace, shows promise for achieving very low nitrogen oxide(s) (NO{sub x}) emissions for commercial furnace applications. The dilute oxygen combustion (DOC) burner achieves very low NO{sub x} through in-furnace dilution of the oxidant stream prior to combustion, resulting in low flame temperatures, thus inhibiting thermal NO{sub x} production. The results of a fundamental and applied research effort on the development of the DOC burner are presented. In addition, the results of a market survey detailing the potential commercial impact of the DOC system are disclosed. The fundamental aspects of the burner development project involved examining the flame characteristics of a natural gas turbulent jet in a high-temperature ({approximately}1366 K) oxidant (7-27% O{sub 2} vol. wet). Specifically, the mass entrainment rate, the flame lift-off height, the velocity field and major species field of the jet were evaluated as a function of surrounding-gas temperature and composition. The measured entrainment rate of the fuel jet decreased with increasing oxygen content in the surrounding high-temperature oxidant, and was well represented by the d{sup +} scaling correlation found in the literature. The measured flame lift-off height decreased with increasing oxygen content and increasing temperature of the surrounding gas. An increase in surrounding-gas oxygen content and/or temperature inhibited the velocity decay within the jet periphery as a function of axial distance as compared to isothermal turbulent jets. However, the velocity measurements were only broadly represented by the d{sup +} scaling correlation. Several DOC burner configurations were tested in a laboratory-scale furnace at a nominal firing rate of 185 kW ({approximately}0.63 MMBtu/h). The flue gas composition was recorded as a function of furnace nitrogen content, furnace temperature, burner geometric arrangement, firing rate, and fuel injection velocity. NO{sub x} emissions increased with increasing furnace nitrogen content and furnace temperature, but remained relatively insensitive to variations in fuel injection velocity and firing rate. NO{sub x} emissions below 5{times}10{sup -3} g/MJ (10 ppm-air equivalent at 3% O{sub 2} dry) were obtained for furnace temperatures below 1533 K (2300{degree}F) and furnace nitrogen levels between 1 and 40%. CO emissions were typically low (<35 ppm). Detailed in- furnace species measurements revealed the importance of the interior furnace circulation patterns, as influenced by fuel and oxidant injection schemes, on pollutant emissions. The combustion stability traits of several DOC burner arrangements were ascertained through furnace pressure measurements, with increased stability occurring as furnace temperature increased and as the separation distance between fuel and oxidant inputs decreased. Based on current market conditions, oxy-fuel conversion of batch steel reheat furnaces with a DOC burner is justified on the basis of utility costs alone. However, conversion of continuous steel reheat furnaces, which are responsible for most steel production, requires additional economic incentives, such as further fuel savings, increased furnace productivity, or emission credits.

NONE

1997-10-01

322

Development of the Moving Least Squares Smooth Particle Hydrodynamics Approach For Inert/Energetic Material Interaction  

NASA Astrophysics Data System (ADS)

PRIMEX-Warhead Systems (PWS) has developed a smooth particle code based upon a methodology developed by G. Dilts (1999) referred to as MLSPH (Moving Least Squares Smooth Paticles Hydrodynamics). The object is to solve general high rate problems associated with the interaction of energetic and inert materials. Some conservative numerical schemes in cylindrical geometry were developed as well 1D, 2D, and 3D cartesian coding. We use a simple neighbor search technique that limits the computation of searching neighbor particles to one order lower compared to the total CPU time of calculation. PWSuses randomly distributed phantom particles to eliminate certain terms in the numerical growth factor, thus improving the stability of the MLSPH method. In fact, the stability factor can be close to unity. The boundary treatment is also naturally implemented by using this approach. The particle size effect has been minimized through rezoning. PWS developed a new numerical technique of second order accuracy that exactly conserves mass and volume. The rezoning technique provides smoother boundary surface and improves stability by naturally moving apart the particles that are close together. This rezoning method can be used to construct a conservative scheme for volume expansion of particles (mass conservation) that keeps the volume sum of particles equal to the volume enclosed by boundaries, this feature is not satisfied in other SPH schemes. We have also started working on the implementation of a general 3D rezoning technique for SPH. The PWS-MLSPH code is able to deal with material interactions between solid, fluid and gas. Several reaction models are contained in the code to solve problems that involves explosives. In particular the burn process of inert materials contained in an explosive matrix is handled with a 'neighbor ignition' method. That allows an explosive particle to be ignited only by another burning explosive particle that is close enough. We will present a calculation involving the interaction of inert tungsten particles in a TNT matrix. The program will eventually be modified to allow for energy release of metallic particles into the reaction zone (as a function of particle size and coating). The figure below depicts a calculation of 100 micron tungsten in a 60/40 volume ratio.

Yao, Jin; Gunger, Michael

2001-06-01

323

Comparison of the processes induced by nitrogen dilution on the photodissociation of silane and disilane at 193 nm  

Microsoft Academic Search

We compare the influence of the dilution of silane and disilane in nitrogen during laser photodissociation to produce silicon at 193nm, at room temperature in a static reaction chamber. The experimental results show that the conversion of the reactant gas and its deposition yield can be controlled by varying adequately the extent of dilution. So, two total pressure regions have

B. Aka; E. Boch

2002-01-01

324

Unidentified Inert Ingredients in Pesticides: Implications for Human and Environmental Health  

PubMed Central

Background By statute or regulation in the United States and elsewhere, pesticide ingredients are divided into two categories: active and inert (sometimes referred to as other ingredients, adjuvants, or coformulants). Despite their name, inert ingredients may be biologically or chemically active and are labeled inert only because of their function in the formulated product. Most of the tests required to register a pesticide are performed with the active ingredient alone, not the full pesticide formulation. Inert ingredients are generally not identified on product labels and are often claimed to be confidential business information. Objectives In this commentary, we describe the shortcomings of the current procedures for assessing the hazards of pesticide formulations and demonstrate that inert ingredients can increase the toxicity of and potential exposure to pesticide formulations. Discussion Inert ingredients can increase the ability of pesticide formulations to affect significant toxicologic end points, including developmental neurotoxicity, genotoxicity, and disruption of hormone function. They can also increase exposure by increasing dermal absorption, decreasing the efficacy of protective clothing, and increasing environmental mobility and persistence. Inert ingredients can increase the phytotoxicity of pesticide formulations as well as the toxicity to fish, amphibians, and microorganisms. Conclusions Pesticide registration should require full assessment of formulations. Evaluations of pesticides under the National Environmental Policy Act, the Endangered Species Act, and similar statutes should include impact assessment of formulations. Environmental monitoring for pesticides should include inert ingredients. To enable independent research and risk assessment, inert ingredients should be identified on product labels. PMID:17185266

Cox, Caroline; Surgan, Michael

2006-01-01

325

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

326

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 3–4-fold compared to the rate under an

Ting Cheng; Ronald H. Baney; James Tulenko

2011-01-01

327

Turboexpanders with dry gas seals and active magnetic bearings in hydrocarbon processing  

SciTech Connect

Since its first application in hydrocarbon processing in the early 1960s, turboexpander design has changed, evolved and improved tremendously. Today, hydrocarbon process designers use turboexpanders for almost all hydrocarbon liquid rejection and hydrocarbon dew point control for onshore and offshore installations. There are presently more than 3,000 turboexpanders operating in hydrocarbon gas processing plants worldwide. Due to the wide application of turboexpanders in hydrocarbon processing, the API-617 committee has assigned a task force to prepare an appendix to API-617 to cover design and manufacturing standards for turboexpanders. Dry gas seals (DGS) were cautiously introduced in the early 1980s for compressors used in hydrocarbon processing. It took almost a decade before dry gas seals found their application in turboexpanders. Dry gas seals were originally utilized to protect cryogenic hydrocarbon process gas from contamination by lubricating oil. Later on, dry gas seals were used to minimized hydrocarbon process gas leakage and also to provide an inert-gas-purged environment for both oil bearings and active magnetic bearings. The former eliminates the lubricating oil dilution problem and the latter made certification of active magnetic bearings by international certifying agencies possible. Active magnetic bearings (AMB), similar to dry gas seals, were originally introduced into hydrocarbon process gas compressors in the mid 1980s. The hydrocarbon processing industry waited half a decade to adopt this innovative technology for turboexpanders in the hydrocarbon process. The first turboexpander with active magnetic bearings was installed on an offshore platform in 1991. High reliability, low capital investment, low capital investment, low operating costs and more compact design have accelerated demand in recent years for turboexpanders with active magnetic bearings. In this paper, the author describes the technology of turboexpanders with dry gas seals and active magnetic bearings. Several applications are presented and performance, reliability and availability data will be presented.

Agahi, R.R.

1999-07-01

328

EPS dilution after SEOs and earnings management  

Microsoft Academic Search

Purpose – Firms are concerned about earnings per share (EPS) dilution after equity issues. The purpose of this paper is to investigate whether firms manage upward their discretionary accruals around seasoned equity offerings (SEOs) to mitigate the impact of dilution on reported earnings. Design\\/methodology\\/approach – The authors employ adjusted discretionary accruals from cash flow statements, normalized by the average common

Hui Di; Dalia Marciukaityte; Eugenie A. Goodwin

2012-01-01

329

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

ERIC Educational Resources Information Center

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

Luo, Yuyan; Kaufman, Lisa; Baillargeon, Renee

2009-01-01

330

Inert filter media for the biofiltration of waste gases – characteristics and biomass control  

Microsoft Academic Search

Soil biofilters and related systems based onthe use of natural filter beds have been usedfor several years for solving specific airpollution problems. Over the past decade,significant improvements have been brought tothese original bioprocesses, among which thedevelopment and use of new inert packingmaterials. The present paper overviews the mostcommon inert packings used in biofiltration ofwaste gases and their major characteristics. Apotential

Christian Kennes; María C. Veiga

2002-01-01

331

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 Parkinson’s disease, there is renewed interest in the ethics of using “active” placebos in surgical trials, where otherwise there are no inert procedures available, and in pharmacological trials, where there are inert substances, but where patients may guess to which arm they

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

2005-01-01

332

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

333

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

334

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

Code of Federal Regulations, 2012 CFR

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

2012-07-01

335

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

Code of Federal Regulations, 2011 CFR

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

2011-07-01

336

Differential isospin-fractionation in dilute asymmetric nuclear matter  

NASA Astrophysics Data System (ADS)

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, Bao-An; Chen, Lie-Wen; Ma, Hong-Ru; Xu, Jun; Yong, Gao-Chan

2007-11-01

337

Endotracheal tube resistance and inertance in a model of mechanical ventilation of newborns and small infants-the impact of ventilator settings on tracheal pressure swings.  

PubMed

Resistive properties of endotracheal tubes (ETTs) are particularly relevant in newborns and small infants who are generally ventilated through ETTs with a small inner diameter. The ventilation rate is also high and the inspiratory time (ti) is short. These conditions effectuate high airway flows with excessive flow acceleration, so airway resistance and inertance play an important role. We carried out a model study to investigate the impact of varying ETT size, lung compliance and ventilator settings, such as peak inspiratory pressure (PIP), positive end expiratory pressure (PEEP) and inspiratory time (ti) on the pressure-flow characteristics with respect to the resistive and inertive properties of the ETT. Pressure at the Y piece was compared to direct measurement of intratracheal pressure (P(trach)) at the tip of the ETT, and pressure drop (?P(ETT)) was calculated. Applying published tube coefficients (Rohrer's constants and inertance), P(trach) was calculated from ventilator readings and compared to measured P(trach) using the root-mean-square error. The most relevant for ?P(ETT) was the ETT size, followed by (in descending order) PIP, compliance, ti and PEEP, with gas flow velocity being the principle in common for all these parameters. Depending on the ventilator settings ?P(ETT) exceeded 8 mbar in the smallest 2.0 mm ETT. Consideration of inertance as an additional effect in this setting yielded a better agreement of calculated versus measured P(trach) than Rohrer's constants alone. We speculate that exact tracheal pressure tracings calculated from ventilator readings by applying Rohrer's equation and the inertance determination to small size ETTs would be helpful. As an integral part of ventilator software this would (1) allow an estimate of work of breathing and implementation of an automatic tube compensation, and (2) be important for gentle ventilation in respiratory care, especially of small infants, since it enables the physician to estimate consequences of altered ventilator settings at the tracheal level. PMID:21799238

Hentschel, Roland; Buntzel, Julia; Guttmann, Josef; Schumann, Stefan

2011-09-01

338

Response to dietary dilution in an omnivorous freshwater turtle: implications for ontogenetic dietary shifts.  

PubMed

Several species of freshwater turtles in the family Emydidae undergo an ontogenetic dietary shift; as juvenile turtles mature, they change from a primarily carnivorous to a primarily herbivorous diet. It has been hypothesized that this shift results from an unfavorable ratio of gut capacity to metabolic rate that prevents small reptiles from processing adequate volumes of plant material to meet their energetic demands. Effects of dietary dilution on intake were evaluated in two size classes of red-eared sliders (Trachemys scripta elegans) to test whether small reptiles have a lower capacity to compensate for low-quality diets through increased intake than do larger conspecifics. Artificial diets with an inert diluent were offered to two size classes of turtles, and mass-specific intakes of dry matter, energy, and nitrogen were calculated. Both small (28.7+/-4.9 g body mass, mean mass+/-SD) and large (1,230+/-94 g body mass) turtles compensated for dietary dilution and maintained constant energy and nitrogen intakes on diets with lower energy content than common aquatic plants. Thus, body size did not affect the ability to respond to nutritional dilution, which suggests that processing limitations imposed by small body size do not constrain juveniles from adopting an herbivorous diet. PMID:9882608

McCauley, S J; Bjorndal, K A

1999-01-01

339

Development and Comparison of Two Types of Cryogen-Free Dilution Refrigerator  

NASA Astrophysics Data System (ADS)

Dilution refrigerators are an important tool used in solid state and quantum fluid physics for cooling to temperatures below 0.3 K. Conventional dilution refrigerators consume a lot of liquid helium, which has to be recharged in a helium bath every few days. Cryogen-free dilution refrigerators, however, do not use liquid helium and then automatic operation by electricity can be possible from room temperature to the mK region. In near future, therefore, most conventional dilution refrigerators will be replaced by cryogen-free refrigerators because they are easy to operate, do not require maintenance and do not consume helium. We have developed two types of cryogen-free dilution refrigerator. One is directly cooled by a pulse tube refrigerator in the same cryostat using copper thin wires as a thermal link, and the other is cooled by a separate Gifford McMahon refrigerator using circulating helium gas through a flexible syphon tube. The latter has been developed as a vibration-free cryogen-free dilution refrigerator. These two types of cryogen-free dilution refrigerator are compared considering several key points: base temperature, precooling time, minimum temperature and vibration amplitude.

Hata, T.; Matsumoto, T.; Obara, K.; Yano, H.; Ishikawa, O.; Handa, A.; Togitani, S.; Nishitani, T.

2014-04-01

340

Development of a constant dilution sampling system for particulate and gaseous pollutant measurements  

NASA Astrophysics Data System (ADS)

This paper presents a new concept of a partial flow sampling system (PFSS), involving a two-stage diluter which operates on the principle of underpressure, while exhaust is sampled through a capillary. Due to the low flowrate through the capillary, the diluter may be sampling from a freely exhausting tailpipe and is not prone to pressure variations in the exhaust line. In addition, the PFSS operates at constant pressure conditions even upstream of diesel particle filters that increase the backpressure in the tailpipe. As a result, the PFSS offers a constant dilution ratio (DR) over any engine or vehicle operation condition. This study presents the diluter concept and a straightforward model developed to calculate the DR, depending on the dilution air flowrate and the diluter underpressure. The model is validated using CO2 as a trace gas, and very good agreement is demonstrated between the calculated and the measured DR values. Following validation, the PFSS is combined with aerosol measurement instruments to measure the exhaust particle concentration of a diesel engine operating at different steady-state modes. For demonstrating the stability of the DR and applicability of the PFSS, measurements are conducted with both heavy duty and light duty diesel exhaust gases. Future applications of this device include gas and particle exhaust measurements both in laboratory environments and on-board vehicles.

Tzamkiozis, T.; Ntziachristos, L.; Amanatidis, S.; Niemelä, V.; Ukkonen, A.; Samaras, Z.

2013-08-01

341

Gas diffusion cell removes carbon dioxide from occupied airtight enclosures  

NASA Technical Reports Server (NTRS)

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

1964-01-01

342

Effects of External EGR Loop on Cycle-to-Cycle Dynamics of Dilute SI Combustion  

SciTech Connect

Operation of spark-ignition (SI) engines with high levels of charge dilution through exhaust gas recirculation (EGR) achieves significant efficiency gains while maintaining stoichiometric operation for compatibility with three-way catalysts. Dilution levels, however, are limited by cyclic variability including significant numbers of misfires that becomes significant with increasing dilution. This variability has been shown to have both stochastic and deterministic components. Stochastic effects include turbulence, mixing variations, and the like, while the deterministic effect is primarily due to the nonlinear dependence of flame propagation rates and ignition characteristics on the charge composition, which is influenced by the composition of residual gases from prior cycles. The dynamics of operation with an external EGR loop differ substantially from those of dilute operation without external recirculation, both in time-scale and cylinder synchronization effects, especially when misfires are encountered. This paper examines these differences and the implications for prior-cycle-based control strategies.

Kaul, Brian C [ORNL; Finney, Charles [ORNL; Wagner, Robert [ORNL; Edwards, Michelle L [ORNL

2014-01-01

343

Thermally induced rotons in two-dimensional dilute Bose gases  

SciTech Connect

We show that rotonlike excitations are thermally induced in a two-dimensional dilute Bose gas as a consequence of the strong phase fluctuations in two dimensions. At low momentum, the rotonlike excitations lead for small enough temperatures to an anomalous phonon spectrum with a temperature-dependent exponent reminiscent of the Kosterlitz-Thouless transition. Despite the anomalous form of the energy spectrum, it is shown that the corresponding effective theory of vortices describes the usual Kosterlitz-Thouless transition. The possible existence of an anomalous normal state in a small temperature interval is also discussed.

Nogueira, Flavio S.; Kleinert, Hagen [Institut fuer Theoretische Physik, Freie Universitaet Berlin, Arnimallee 14, D-14195 Berlin (Germany)

2006-03-01

344

Terahertz Radiation from Magnetic Excitations in Diluted Magnetic Semiconductors  

NASA Astrophysics Data System (ADS)

We probed, in the time domain, the THz electromagnetic radiation originating from spins in CdMnTe diluted magnetic semiconductor quantum wells containing high-mobility electron gas. Taking advantage of the efficient Raman generation process, the spin precession was induced by low power near-infrared pulses. We provide a full theoretical first-principles description of spin-wave generation, spin precession, and of emission of THz radiation. Our results open new perspectives for improved control of the direct coupling between spin and an electromagnetic field, e.g., by using semiconductor technology to insert the THz sources in cavities or pillars.

Rungsawang, R.; Perez, F.; Oustinov, D.; Gómez, J.; Kolkovsky, V.; Karczewski, G.; Wojtowicz, T.; Madéo, J.; Jukam, N.; Dhillon, S.; Tignon, J.

2013-04-01

345

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

346

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

347

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

348

Sample Diluter for Detecting Hypergolic Propellants and Other Toxic or Hazardous Gases  

NASA Technical Reports Server (NTRS)

Hardware was developed to dilute vapor samples of purged hypergolic propellants (with air) into the range of existing instruments for detection of such toxic vapors. Since these detectors are normally used to monitor at the threshold limit value (TLV), most do not have quantitative capability at percent levels which relate to lower explosion limit (LEL) and fire hazards. For example, the upper limits of Energetic Sciences (ESI) 6000 series detectors used at KSC are 200 parts per million (ppm) for monomethyl hydrazine (MMH) and 500 ppm for nitrogen dioxide (NO2) arising from decomposition of nitrogen tetroxide (N2O4). Orbiter Processing Facility (OPF) personnel servicing Shuttle thrusters need to measure up to 250 ppm MMH and 7500 ppm NO2 with portable, intrinsically safe instruments. Our objective was to quickly fabricate a sample diluter out of existing materials as a temporary measure while other parallel efforts were conducted to provide a commercial or in-house-developed instrument to detect high propellant levels. A 3 to 1 diluter would bring 500 ppm MMH into the range of the existing fuel ESI, and a 30 to 1 diluter would do the same for NO2. In this way, familiar equipment already available would be used, resulting in minimal paperwork, safety, and training impacts and low cost. An MMH vapor sample-diluter was constructed from a 1/4-inch Kynar tee, along with specially designed lengths of sample and dilution tubing. The sample line was 3 feet of Bev-A-Line 4, 1/4 inch tube leading to the straight run of the tee. The side run of the tee had a 17-inch length of Bev-A-Line 4, 1/4-inch tube, for nominal 3 to 1 dilution. A gas sample bag was prepared and assayed at 113 ppm MMH, and diluted vapor sarnples were assayed at 39.5 ppm, or a measured dilution of 2.9 to 1. For NO2, a 316 stainless steel (SS) 1/8-inch tee with 49.5 inches of coiled, 1/8-inch outside diameter (OD) 316 SS tubing was used as the sarnpling end of the dilution system. The side run of the tee was open. The measured dilution ratio, based on the input value of 6,480 ppm NO2 and the average output value of 233 ppm, was 28 to 1. Thus, sample-diluters were successful in diluting concentrated hypergolic propellant vapors, both MMH and N2O4, into the ranges of existing TLV detectors.

Barile, R. G.; Hodge, T. R.; Meneghelli, B. J.; Gursky, R.; Lueck, D. E.

1997-01-01

349

Sample Diluter for Detecting Hypergolic Propellants and other Toxic or Hazardous Gases  

NASA Technical Reports Server (NTRS)

Hardware was developed to dilute vapor samples of purged hypergolic propellants (with air) into the range of existing instruments for detection of such toxic vapors. Since these detectors are normally used to monitor at the threshold limit value (TLV), most do not have quantitative capability at percent levels which relate to lower explosion limit (LEL) and fire hazards. For example, the upper limits of Energetic Sciences (ESI) 6000 series detectors used at KSC are 200 parts per million (ppm) for monomethyl hydrazine (MMH) and 500 ppm for nitrogen dioxide (NO2) arising from decomposition of nitrogen tetroxide (N2O4). Orbiter Processing Facility (OPF) personnel servicing Shuttle thrusters need to measure up to 250 ppm MMH and 7,500 ppm NO2 with portable, intrinsically safe instruments. Our objective was to quickly fabricate a sample diluter out of existing materials as a temporary measure while other parallel efforts were conducted to provide a commercial or in-house-developed instrument to detect high propellant levels. A 3 to 1 diluter would bring 500 ppm MMH into the range of the existing fuel ESI, and a 30 to 1 diluter would do the same for NO2. In this way, familiar equipment already available would be used, resulting in minimal paperwork, safety, and training impacts and low cost. An MMH vapor sample-diluter was constructed from a 1/4-inch Kynar tee, along with specially designed lengths of sample and dilution tubing. The sample line was 3 feet of Bev-A-Line 4, 1/4-inch tube leading to the straight run of the tee. The side run of the tee had a 17-inch length of Bev-A-Line 4, 1/4-inch tube, for nominal 3 to 1 dilution. A gas sample bag was prepared and assayed at 113 ppm ppm MMH, and diluted vapor samples were assayed at 39.5 ppm, or a measured dilution of 2.9 to 1. For NO2, a 316 stainless steel (SS) 1/8-inch tee with 49.5 inches of coiled, 1/8-inch outside diameter (OD) 316 SS tubing was used as the sampling end of the dilution system. The side run of the tee was open. The measured dilution ratio, based on the input value of 6,480 ppm NO2, and the average output value of 233 ppm, was 28 to 1. Thus, sample-diluters were successful in diluting concentrated hypergolic propellant vapors, both MMH and N2O4 into the ranges of existing TLV detectors.

Barile, R. G.; Hodge, T. R.; Meneghelli, B. J.; Gursky, R.; Lueck, D. E.

1997-01-01

350

40 CFR 174.533 - Glycine max Herbicide-Resistant Acetolactate Synthase (GM-HRA) inert ingredient; exemption from...  

Code of Federal Regulations, 2013 CFR

...Herbicide-Resistant Acetolactate Synthase (GM-HRA) inert ingredient; exemption from...Herbicide-Resistant Acetolactate Synthase (GM-HRA) inert ingredient; exemption from...herbicide-resistant acetolactate synthase (GM-HRA) enzyme in or on the food...

2013-07-01

351

21 CFR 864.5240 - Automated blood cell diluting apparatus.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Automated blood cell diluting apparatus. 864.5240 Section...Devices § 864.5240 Automated blood cell diluting apparatus. (a) Identification. An automated blood cell diluting apparatus is a fully...

2010-04-01

352

21 CFR 864.5240 - Automated blood cell diluting apparatus.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Automated blood cell diluting apparatus. 864.5240 Section...Devices § 864.5240 Automated blood cell diluting apparatus. (a) Identification. An automated blood cell diluting apparatus is a fully...

2013-04-01

353

40 CFR 1065.667 - Dilution air background emission correction.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Dilution air background emission correction...AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES...1065.667 Dilution air background emission correction...first determine the total flow of dilution air, n...

2011-07-01

354

40 CFR 1065.667 - Dilution air background emission correction.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Dilution air background emission correction...AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES...1065.667 Dilution air background emission correction...first determine the total flow of dilution air, n...

2010-07-01

355

40 CFR 1065.667 - Dilution air background emission correction.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Dilution air background emission correction...AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES...1065.667 Dilution air background emission correction...first determine the total flow of dilution air, n...

2012-07-01

356

40 CFR 1065.667 - Dilution air background emission correction.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Dilution air background emission correction...AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES...1065.667 Dilution air background emission correction...first determine the total flow of dilution air, n...

2013-07-01

357

21 CFR 864.5240 - Automated blood cell diluting apparatus.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Automated blood cell diluting apparatus. 864.5240 Section...Devices § 864.5240 Automated blood cell diluting apparatus. (a) Identification. An automated blood cell diluting apparatus is a fully...

2011-04-01

358

Reduction Kinetics of Iron Ore-Graphite Composite Pellets in a Packed-Bed Reactor under Inert and Reactive Atmospheres  

NASA Astrophysics Data System (ADS)

The rate of reduction of iron ore-graphite composite pellets in a packed-bed reactor under controlled atmosphere (inert and reducing) has been studied through experiments and modeling exercises. A customized high-mass, high-temperature thermogravimetric setup was constructed to carry out reduction experiments in a packed-bed reactor. A very low overall apparent activation energy estimated from experimental data indicates that the packed-bed reduction is unlikely to be chemical kinetics controlled. A kinetic model has been developed to calculate the temporal evolution of various phases of iron oxides and metallic iron. The rate-dependent parameters of the kinetic model are estimated from experimental data by applying an optimization tool. The predicted phases at various degrees of reduction were verified by X-ray diffraction and metallographic investigation, and a reasonable agreement between the results has been observed. It is observed that both the rate and the extent of metallic-iron production increase under reactive atmosphere. In addition, a simplified thermal model has been developed to ascertain the role of heat transfer on the kinetics of the reduction process under inert atmosphere. The reduction kinetics of the packed bed under reactive atmosphere, on the other hand, is not controlled by heat transfer and might possibly be controlled by CO-gas mass transfer through the pellets.

Chowdhury, G. M.; Roy, G. G.; Roy, S. K.

2008-04-01

359

Phenomenology of the inert (2+1) and (4+2) Higgs doublet models  

NASA Astrophysics Data System (ADS)

We make a phenomenological study of a model with two inert doublets plus one Higgs doublet [I(2+1)HDM] which is symmetric under a Z2 group, preserved after electroweak symmetry breaking by the vacuum alignment (0,0,v). This model may be regarded as an extension to the model with one inert doublet plus one Higgs doublet [I(1+1)HDM], by the addition of an extra inert scalar doublet. The neutral fields from the two inert doublets provide a viable dark matter (DM) candidate which is stabilized by the conserved Z2 symmetry. We study the new Higgs decay channels offered by the scalar fields from the extra doublets and their effect on the standard model Higgs couplings, including a new decay channel into (off-shell) photon(s) plus missing energy, which distinguishes the I(2+1)HDM from the I(1+1)HDM. Motivated by supersymmetry, which requires an even number of doublets, we then extend this model into a model with four inert doublets plus two Higgs doublets [I(4+2)HDM] and study the phenomenology of the model with the vacuum alignment (0,0,0,0,v ,v). This scenario offers a wealth of Higgs signals, the most distinctive ones being cascade decays of heavy Higgs states into inert ones. Finally, we also remark that the smoking-gun signature of all the considered models is represented by invisible Higgs decays into the lightest inert Higgs bosons responsible for DM.

Keus, Venus; King, Stephen F.; Moretti, Stefano

2014-10-01

360

Helium Dilution Cryocooler for Space Applications  

NASA Technical Reports Server (NTRS)

NASA's New Millenium Program Space Technology presents the Helium Dilution Cryocooler for Space Applications. The topics include: 1) Capability; 2) Applications; and 3) Advantages. This paper is in viewgraph form.

Roach, Pat; Hogan, Robert (Technical Monitor)

2001-01-01

361

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

NASA Astrophysics Data System (ADS)

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

Fizia, Marcin; Sacha, Krzysztof

2012-02-01

362

Calorimetric Study of Diluted Spin Ice Materials  

NASA Astrophysics Data System (ADS)

Spin ice materials Dy2Ti2O7 and Ho2Ti2O7 have been the subject of ongoing interest for over ten years. The cooperative magnetic ground state can be mapped onto the proton disordered ground state in water ice, and its residual entropy follows the same Pauling's estimate. Interestingly it was found in a previous study that, upon dilution of the magnetic rare earth ions Dy^3+ and Ho^3+ by non-magnetic substitutes Y^3+, the residual entropy depends non-monotonically on the dilution level. In this work we investigate through Monte Carlo simulations microscopic models to account quantitatively for the calorimetric experimental measurements, and thus also the residual entropies as a function of dilution. Features of the dilution physics in the specific heat are captured quantitatively by the microscopic models and the interplay between dilution and frustration is understood on the basis of a Bethe lattice calculation. The effect of the dipolar interactions between magnetic spins are exposed numerically for various dilution concentrations. Our work explains the previous discrepancy of the residual entropy between different species of rare earth ions and the generalized Pauling's estimate.

Lin, Taoran; Ke, Xianglin; Thesberg, Mischa; Schiffer, Peter; Melko, Roger; Gingras, Michel

2012-02-01

363

Analyses of turbulent flow fields and aerosol dynamics of diesel engine exhaust inside two dilution sampling tunnels using the CTAG model.  

PubMed

Experimental results from laboratory emission testing have indicated that particulate emission measurements are sensitive to the dilution process of exhaust using fabricated dilution systems. In this paper, we first categorize the dilution parameters into two groups: (1) aerodynamics (e.g., mixing types, mixing enhancers, dilution ratios, residence time); and (2) mixture properties (e.g., temperature, relative humidity, particle size distributions of both raw exhaust and dilution gas). Then we employ the Comprehensive Turbulent Aerosol Dynamics and Gas Chemistry (CTAG) model to investigate the effects of those parameters on a set of particulate emission measurements comparing two dilution tunnels, i.e., a T-mixing lab dilution tunnel and a portable field dilution tunnel with a type of coaxial mixing. The turbulent flow fields and aerosol dynamics of particles are simulated inside two dilution tunnels. Particle size distributions under various dilution conditions predicted by CTAG are evaluated against the experimental data. It is found that in the area adjacent to the injection of exhaust, turbulence plays a crucial role in mixing the exhaust with the dilution air, and the strength of nucleation dominates the level of particle number concentrations. Further downstream, nucleation terminates and the growth of particles by condensation and coagulation continues. Sensitivity studies reveal that a potential unifying parameter for aerodynamics, i.e., the dilution rate of exhaust, plays an important role in new particle formation. The T-mixing lab tunnel tends to favor the nucleation due to a larger dilution rate of the exhaust than the coaxial mixing field tunnel. Our study indicates that numerical simulation tools can be potentially utilized to develop strategies to reduce the uncertainties associated with dilution samplings of emission sources. PMID:23190276

Wang, Yan Jason; Yang, Bo; Lipsky, Eric M; Robinson, Allen L; Zhang, K Max

2013-01-15

364

Thermal conductivity and sound attenuation in dilute atomic Fermi gases  

SciTech Connect

We compute the thermal conductivity and sound attenuation length of a dilute atomic Fermi gas in the framework of kinetic theory. Above the critical temperature for superfluidity, T{sub c}, the quasiparticles are fermions, whereas below T{sub c}, the dominant excitations are phonons. We calculate the thermal conductivity in both cases. We find that at unitarity the thermal conductivity {kappa} in the normal phase scales as {kappa}{proportional_to}T{sup 3/2}. In the superfluid phase we find {kappa}{proportional_to}T{sup 2}. At high temperature the Prandtl number, the ratio of the momentum and thermal diffusion constants, is 2/3. The ratio increases as the temperature is lowered. As a consequence we expect sound attenuation in the normal phase just above T{sub c} to be dominated by shear viscosity. We comment on the possibility of extracting the shear viscosity of the dilute Fermi gas at unitarity using measurements of the sound absorption length.

Braby, Matt; Chao Jingyi; Schaefer, Thomas [Physics Department, North Carolina State University, Raleigh, North Carolina 27695 (United States)

2010-09-15

365

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

Microsoft Academic Search

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

W. Ketterle

2000-01-01

366

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

Code of Federal Regulations, 2010 CFR

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

2010-07-01

367

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

... § 75.1107-12 Inerting of mine atmosphere prohibited. No fire suppression device designed to control fire by total flooding shall be installed to protect unattended underground equipment except in enclosed dead-end entries or enclosed rooms....

2014-07-01

368

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

DOEpatents

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

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

2002-01-01

369

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

DOEpatents

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

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

2002-01-01

370

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

SciTech Connect

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

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

2013-03-15

371

Effects of N 2 gas on preheated laminar LPG jet diffusion flame  

Microsoft Academic Search

This paper presents an experimental investigation of the inert gas effect on flame length, NOx and soot free length fraction (SFLF) in a laminar LPG diffusion flame. Besides this, flame radiant fraction and temperature are also measured to explain observed NOx emission and SFLF. The inert is added to both air and fuel stream at each base line condition by

D. P. Mishra; P. Kumar

2010-01-01

372

Application of the gas phase condensation to the preparation of nanoparticles  

Microsoft Academic Search

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

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

1999-01-01

373

Use of coconut coir fibers as an inert solid support for production of cyclosporin A  

Microsoft Academic Search

In the present study, coconut coir was evaluated as an inert support for the production of cyclosporin A (CyA) using Tolypocladium inflatum MTCC 557 by solid state fermentation. Initially, four different inert supports such as coconut coir, polyurethane foam, polystyrene\\u000a beads, and sugarcane baggase were screened using different production media as moistening agents for the maximum production\\u000a of CyA. Different

Shrikant A. Survase; Celine Bacigalupi; Uday S. Annapure; Rekha S. Singhal

2009-01-01

374

Extended Gross-Pitaevskii description for the dynamics of thermal dilute Bose gases  

NASA Astrophysics Data System (ADS)

We introduce a technique to simulate the dynamics of a thermal dilute Bose gas. With the method of the nonequilibrium statistical operator, a correction to the Gross-Pitaevskii equation (GPE) is derived. This modification of the GPE describes spontaneous scattering processes. It regularizes the ultraviolet catastrophe and captures the dynamics of the particles at all energies, including the tail of the momentum distribution. We apply our model to the simulation of an evaporative cooling quench of a two-dimensional Bose gas.

Wouters, Michiel

2014-09-01

375

The role of "inert" surface chemistry in marine biofouling prevention.  

PubMed

The settlement and colonization of marine organisms on submerged man-made surfaces is a major economic problem for many marine industries. The most apparent detrimental effects of biofouling are increased fuel consumption of ships, clogging of membranes and heat exchangers, disabled underwater sensors, and growth of biofoulers in aquaculture systems. The presently common-but environmentally very problematic-way to deal with marine biofouling is to incorporate biocides, which use biocidal products in the surface coatings to kill the colonizing organisms, into the surface coatings. Since the implementation of the International Maritime Organization Treaty on biocides in 2008, the use of tributyltin (TBT) is restricted and thus environmentally benign but effective surface coatings are required. In this short review, we summarize the different strategies which are pursued in academia and industry to better understand the mechanisms of biofouling and to develop strategies which can be used for industrial products. Our focus will be on chemically "inert" model surface coatings, in particular oligo- and poly(ethylene glycol) (OEG and PEG) functionalized surface films. The reasons for choosing this class of chemistry as an example are three-fold: Firstly, experiments on spore settlement on OEG and PEG coatings help to understand the mechanism of non-fouling of highly hydrated interfaces; secondly, these studies defy the common assumption that surface hydrophilicity-as measured by water contact angles-is an unambiguous and predictive tool to determine the fouling behavior on the surface; and thirdly, choosing this system is a good example for "interfacial systems chemistry": it connects the behavior of unicellular marine organisms with the antifouling properties of a hydrated surface coating with structural and electronic properties as derived from ab initio quantum mechanical calculations using the electronic wave functions of oxygen, hydrogen, and carbon. This short review is written to outline for non-experts the hierarchical structure in length- and timescale of marine biofouling and the role of surface chemistry in fouling prevention. Experts in the field are referred to more specialized recent reviews. PMID:20407695

Rosenhahn, Axel; Schilp, Sören; Kreuzer, Hans Jürgen; Grunze, Michael

2010-05-01

376

The effects of heating and dilution on the rheological and physical properties of Tank 241-SY-101 waste  

SciTech Connect

Of the 177 high-level waste underground storage tanks at the Hanford Site, 25 have been identified as being potentially capable of generating and releasing flammable gas. Tank 241-SY-101 has exhibited periodic releases of gas, and in some cases the gas released has exceeded the lower flammable gas limit. The components of the released gas from Tank 241-SY-101 are hydrogen, nitrous oxide, nitrogen, ammonia, carbon monoxide, and methane. A mitigation strategy that may effectively reduce the retention and release of these gases and the release of flammable gases is dilution coupled with eating of the tank wastes. The purpose of this work was to determine changes in rheological and physical properties caused by heating and dilution of actual 241-SY-101 waste. In May and December 1991, following periodic gas releases, samples of the waste in Tank 241-SY-101 were obtained. Current work quantified the effects of heating coupled with NaOH dilution of a combination of waste samples from Tank 241-SY-101 characteristic of a non-convective layer. The experimental approach and results of this heating and dilution study on Tank 241-SY-101 waste samples are described in Sections 2 and 3, respectively. In Section 3.1, a discussion of the rheological properties of the waste as a function of shearing forces, volume percent dilution, and temperature is presented. In Section 3.2, the physical properties of the waste dilutions are described, including the densities of the slurry, filtered solids, and filtrate; the settling behavior; and the percent filtered solids in the composite sample and each of the composite dilutions. A brief discussion of the results and uncertainties is given is Section 3.3. The conclusions of this investigation are reported in Section 4.

Tingey, J.M.; Bredt, P.R.; Shade, E.H.

1994-10-01

377

Experiments in dilution jet mixing  

NASA Technical Reports Server (NTRS)

Experimental results are given on the mixing of a single row of jets with an isothermal mainstream in a straight duct, to include flow and geometric variations typical of combustion chambers in gas turbine engines. The principal conclusions reached from these experiments were: at constant momentum ratio, variations in density ratio have only a second-order effect on the profiles; a first-order approximation to the mixing of jets with a variable temperature mainstream can be obtained by superimposing the jets-in-an isothermal-crossflow and mainstream profiles; flow area convergence, especially injection-wall convergence, significantly improves the mixing; for opposed rows of jets, with the orifice centerlines in-line, the optimum ratio of orifice spacing to duct height is one half of the optimum value for single side injection at the same momentum ratio; and for opposed rows of jets, with the orifice centerlines staggered, the optimum ratio of orifice spacing to duct height is twice the optimum value for single side injection at the same momentum ratio.

Holdeman, J. D.; Srinivasan, R.; Berenfeld, A.

1983-01-01

378

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

E-print Network

Cryogenic Liquid Usage in the Laboratory Page 1 of 4 March 2009 Standard for Inert Cryogenic Liquid Usage in the Laboratory In University workplaces, the storage, handling and dispensing of cryogenic liquids (e.g. liquid-up. Appropriate controls must be implemented wherever cryogenics are in use. This standard outlines some general

Chan, Hue Sun

379

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

E-print Network

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

Eseltine, Dustin E.

2012-02-14

380

Respiratory and plumage gas volumes in unrestrained diving ducks (Aythya affinis).  

PubMed

Closed-circuit plethysmography and inert gas equilibration analysis were used to measure the volumes of gas in the respiratory system and plumage at the end of voluntary dives in unrestrained lesser scaup (Aythya affinis). Total (respiratory plus plumage) gas volumes were measured by helium dilution and estimated from body mass, body tissue density and buoyant force. These two techniques yielded results that differed by only 2.1 +/- 1.5%. Buoyancy decreased from a maximum of 3.46 +/- 0.16 N at immersion to a minimum of 2.65 +/- 0.16 N at 1.5 m depth at the end of the feeding phase of voluntary dives. At 0.193 +/- 0.013 L BTPS, the respiratory system contributed 52% of the initial buoyancy and 65% of the minimum value. The increasing relative influence of the respiratory system on buoyancy was due to the loss of 47 +/- 5% of the air in the plumage layer during the dive. These data differ significantly from estimates based on restrained ducks, and this has implications for modelling of mechanical costs of diving, oxygen storage capacity and thermal insulation in foraging ducks. PMID:7624614

Stephenson, R

1995-05-01

381

Method and burner apparatus for flaring inert vitiated waste gases  

SciTech Connect

This paper discusses burner apparatus for flaring waste gases. It comprises a first tubular member for discharging waste gases into the atmosphere having an inlet end and a discharge end; a second tubular member positioned around at least the discharge end portion of the first tubular member whereby a discharge space is provided between the first and second tubular members around the adjacent the discharge end of the first tubular member; burner means disposed within the discharge space around and adjacent the discharge end of the first tubular member for discharging and igniting fuel gas therein; fuel gas conduit means sealingly connected to the burner means for connecting the burner means to a source of fuel gas; and combustion air conduit means sealingly connected to the discharge space for connecting the space to a source of combustion air whereby combustion air supplied to the discharge space. It is mixed with fuel gas supplied to and discharged from the burner means. The mixture is ignited, discharged from the discharge space and burned in a stable envelope around waste gases discharged from the first tubular member, and a portion of the waste gases is heated to the ignition temperature thereof, ignited and burned thereby providing heat and ignition to the remaining waste gases.

Schwartz, R.E.; Noble, R.K.

1990-12-04

382

Diluted magnetic semiconductor nanowires exhibiting magnetoresistance  

DOEpatents

A method for is disclosed for fabricating diluted magnetic semiconductor (DMS) nanowires by providing a catalyst-coated substrate and subjecting at least a portion of the substrate to a semiconductor, and dopant via chloride-based vapor transport to synthesize the nanowires. Using this novel chloride-based chemical vapor transport process, single crystalline diluted magnetic semiconductor nanowires Ga.sub.1-xMn.sub.xN (x=0.07) were synthesized. The nanowires, which have diameters of .about.10 nm to 100 nm and lengths of up to tens of micrometers, show ferromagnetism with Curie temperature above room temperature, and magnetoresistance up to 250 Kelvin.

Yang, Peidong (El Cerrito, CA); Choi, Heonjin (Seoul, KR); Lee, Sangkwon (Daejeon, KR); He, Rongrui (Albany, CA); Zhang, Yanfeng (El Cerrito, CA); Kuykendal, Tevye (Berkeley, CA); Pauzauskie, Peter (Berkeley, CA)

2011-08-23

383

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

384

Reception and study of lunar surface material in inert gas medium. [considering laboratory vacuum receiving chamber  

NASA Technical Reports Server (NTRS)

The reception and study of lunar material returned by the Luna 16 space station is described. The layout of a vacuum receiving chamber for working with material in a helium atmosphere is examined along with the main operations involved in extracting the material from the ampule and drill.

Surkov, Y. A.; Rudnitskiy, Y. M.; Glotov, V. A.

1974-01-01

385

NIF Inert Gas/Vacuum Management Prestart Review Phase 3 - Permit Spatial Filter Vacuum  

SciTech Connect

A Management Prestart Review (MPR) for the National Ignition Facility (NIF) vacuum testing of spatial filters, the Cavity Spatial Filter (CSF) and the Transport Spatial Filter (TSF), was conducted during March 2001. The review was performed to determine the readiness of the Beamline Infrastucture System (BIS) team and the Integration Management and Installation (IMI) contractor to start the vacuum testing of the components and assemblies that constitute the four CSF clusters and four TSF clusters in the NIF laser. This review assures that appropriate engineering, planning and management is in place to start this testing. Completion and acceptance of this report satisfies the LLNL requirement for MPRs to be conducted whenever a significant new risk is introduced into a project and is an essential part of the ISM work authorization process.

Williams, J; Beavers, T; Bryan, S; Hermes, G; Patton, H

2001-03-01

386

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

PubMed

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

Gäfvert, T; Pagels, J; Holm, E

2003-01-01

387

Control of ion species in inductively coupled oxidation plasma by inert gas mixing  

SciTech Connect

We have controlled and investigated the ion density ratio ([O{sup +}]/[O{sub 2}{sup +}]) in oxidation plasma by He and Xe mixing. The ion density ratio increases from 0.26 to 0.97 by He mixing, and decreases to 0.015 by Xe mixing. The ratio is a strong function of the electron density and electron temperature. When the other conditions are fixed, the ion density ratio is proportional to the electron density in all the cases: the He/O{sub 2} and Xe/O{sub 2} mixtures as well as pure O{sub 2} plasma. This may be due to the increase in the dissociation rate and the process of ionization from O to O{sup +}. The rate of increase in the ion density ratio with the electron density is different in the two cases: In the He/O{sub 2} mixture, the rate of increase is slightly higher than that in the pure O{sub 2} plasma. However, the rate is very low in the Xe/O{sub 2} mixture. In the Xe/O{sub 2} mixture, the ion density ratio is actually a strong function of the electron temperature rather than the electron density.

Bai, K. H.; Chang, H. Y. [Memory Division, Semiconductor Business, Samsung Electronics, San no. 16 Banwol - Ri, Taean-Eup, Hwasung-City, Gyeonggi-Do, 445-701 (Korea, Republic of); Department of Physics, Korea Advanced Institute of Science and Technology, Taejon 305-701 (Korea, Republic of)

2006-12-01

388

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

NASA Astrophysics Data System (ADS)

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

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

2002-01-01

389

Hot cracking in tungsten inert gas welding of magnesium alloy AZ91D  

E-print Network

strength. Considerable researches have been carried out to study optimisation of die casting parameters,391D.13­16 Previous researches have identified porosity as a major problem in welding of AZ91D die castings.10,11 Hot cracking is also known as one of the problems in joining magnesium alloys,12

Zhou, Wei

390

The inert gas effect on the rate of evaporation of zinc and cadmium  

Microsoft Academic Search

An experimental study has been made to investigate the effect of argon and helium on the rate of evaporation of zinc and cadmium\\u000a under one atmosphere pressure at temperatures ranging from 500 to 850°C. The experimental results were compared with the maximum\\u000a rates calculated using the effusion formula as well as with values obtained using two different types of equations

P. C. S. Wu; T. J. O’keefe; F. Kisslinger

1980-01-01

391

The inert gas effect on the rate of evaporation of zinc and cadmium  

NASA Astrophysics Data System (ADS)

An experimental study has been made to investigate the effect of argon and helium on the rate of evaporation of zinc and cadmium under one atmosphere pressure at temperatures ranging from 500 to 850°C. The experimental results were compared with the maximum rates calculated using the effusion formula as well as with values obtained using two different types of equations based on kinetic theory, diffusion theory, and empirical data. Equations have been derived for expressing the rate of evaporation of zinc and cadmium in both argon and helium as functions of temperature of the liquid zinc and cadmium. It was found that the rates of evaporation of zinc and cadmium were higher in helium than in argon, with the difference increasing with increasing temperature. It was also found that the experimental results obtained in argon agree with the calculated values better than those obtained in helium.

Wu, P. C. S.; O'Keefe, T. J.; Kisslinger, F.

1980-12-01

392

The inert gas effect on the rate of evaporation of zinc and cadmium  

Microsoft Academic Search

An experimental study has been made to investigate the effect of argon and helium on the rate of evaporation of zinc and cadmium under one atmosphere pressure at temperatures ranging from 500 to 850°C. The experimental results were compared with the maximum rates calculated using the effusion formula as well as with values obtained using two different types of equations

P. C. S. Wu; T. J. O'Keefe; F. Kisslinger

1980-01-01

393

Detection thresholds for phenyl ethyl alcohol using serial dilutions in different solvents.  

PubMed

Detection thresholds are typically obtained by presenting a subject with serial dilutions of an odorant. Many factors, including the solvent used to dilute the odorant, can influence the measurement of detection thresholds. Differences have been reported in detection thresholds for phenyl ethyl alcohol (PEA) when different solvents are used. In this study we used gas chromatography (GC) to investigate further the effect of solvent on odor detection thresholds. We used a single ascending method and serial dilutions of PEA in four different solvents--liquid paraffin (LP), mineral oil (MO), propylene glycol (PG) and dipropylene glycol (DPG)--to determine the PEA thresholds for 31 adult subjects. For each solvent, we prepared eight serial log base 10 step dilutions (1-8), with corresponding liquid PEA concentrations of 6.3 x 10(1)-6.3 x 10(-6) (% v/v). We found that the threshold concentrations for PEA in LP (step 6.5) and PEA in MO (step 5.5) were significantly lower (P < 0.05) than for PEA in PG (step 4.0) and DPG (step 4.0) We then used GC to measure both the liquid and gas PEA concentrations for the dilution steps prepared with LP and PG. Although there were large threshold differences in the liquid concentrations of PEA in LP and PG, the headspace gas concentrations of PEA were the same. These results demonstrate the importance of determining the gas concentration of odorant stimuli when performing odor threshold measurements, in particular when comparing odor detection thresholds obtained using different solvents. PMID:12502521

Tsukatani, Toshiaki; Miwa, Takaki; Furukawa, Mitsuru; Costanzo, Richard M

2003-01-01

394

Geochemical detection of carbon dioxide in dilute aquifers  

SciTech Connect

Carbon storage in deep saline reservoirs has the potential to lower the amount of CO{sub 2} emitted to the atmosphere and to mitigate global warming. Leakage back to the atmosphere through abandoned wells and along faults would reduce the efficiency of carbon storage, possibly leading to health and ecological hazards at the ground surface, and possibly impacting water quality of near-surface dilute aquifers. We use static equilibrium and reactive transport simulations to test the hypothesis that perturbations in water chemistry associated with a CO{sub 2} gas leak into dilute groundwater are important measures for the potential release of CO{sub 2} to the atmosphere. Simulation parameters are constrained by groundwater chemistry, flow, and lithology from the High Plains aquifer. The High Plains aquifer is used to represent a typical sedimentary aquifer overlying a deep CO{sub 2} storage reservoir. Specifically, we address the relationships between CO{sub 2} flux, groundwater flow, detection time and distance. The CO{sub 2} flux ranges from 10{sup 3} to 2 x 10{sup 6} t/yr (0.63 to 1250 t/m{sup 2}/yr) to assess chemical perturbations resulting from relatively small leaks that may compromise long-term storage, water quality, and surface ecology, and larger leaks characteristic of short-term well failure.

Carroll, S; Hao, Y; Aines, R

2009-03-27

395

Electron Density of States of Dilute Alloys.  

National Technical Information Service (NTIS)

The change in the electron density of states with dilute alloying is directly related to the shielding of the added impurities. If there is no volume change on alloying, the change in rho (E), the density of states at energy E, is proportional to the exce...

E. A. Stern

1969-01-01

396

LAKE RESTORATION BY DILUTION: MOSES LAKE, WASHINGTON  

EPA Science Inventory

Dilution water, low in macronutrients, was added to Moses Lake on three occasions in 1977 and once in 1978 during the spring-summer period. The addition resulted in reducing the annual average inflow concentration of phosphorus from about 130-140 micrograms/l to 100 micrograms/l....

397

Resistance Minimum in Dilute Magnetic Alloys  

Microsoft Academic Search

Based on the s-d interaction model for dilute magnetic alloys we have calculated the scattering probability of the conduction electrons to the second Born approximation. Because of the dynamical character of the localized spin system, the Pauli principle should be taken into account in the intermediate states of the second order terms. Thus the effect of the Fermi sphere is

Jun Kondo

1964-01-01

398

Surface Pretreatment Based On Dilute Hexafluorozirconic Acid  

Microsoft Academic Search

Two surface pretreatments based on dilute hexafluorozirconic acid (FZ) solution, a simple FZ and a modified FZ or MFZ, were studied as replacements for the phosphating process. The FZ conversion coatings were deposited on cold rolled steel (CRS) substrates by immersion treatment. AFM images reveal that the coating surface exhibited small features tens of nm in size and clusters of

Y. Zhai; Z. Zhao; G. S. Frankel; J. Zimmerman; T. Bryden; W. Fristad

399

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

PubMed

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

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

2014-08-30

400

Effects of Inert Dust Clouds on the Extinction of Strained, Laminar Flames at Normal and Micro Gravity  

NASA Technical Reports Server (NTRS)

A combined experimental and detailed numerical study was conducted on the interaction between chemically inert solid particles and strained, atmospheric methane/air and propane/air laminar flames, both premixed and non-premixed. Experimentally, the opposed jet configuration was used with the addition of a particle seeder capable of operating in conditions of varying gravity. The particle seeding system was calibrated under both normal and micro gravity and a noticeable gravitational effect was observed. Flame extinction experiments were conducted at normal gravity by seeding inert particles at various number densities and sizes into the reacting gas phase. Experimental data were taken for 20 and 37 (mu) nickel alloy and 25 and 60 (mu) aluminum oxide particles. The experiments were simulated by solving along the stagnation streamline the conservation equations of mass, momentum, energy, and species conservation for both phases, with detailed descriptions of chemical kinetics, molecular transport, and thermal radiation. The experimental data were compared with numerical simulations, and insight was provided into the effects on extinction of the fuel type, equivalence ratio, flame configuration, strain rate. particle type. particle size. particle mass, delivery rate. the orientation of particle injection with respect to the flame and gravity. It was found that for the same injected solid mass, larger particles can result in more effective flame cooling compared to smaller particles, despite the fact that equivalent masses of the larger particles have smaller total surface area to volume ratio. This counter-intuitive finding resulted from the fact that the heat exchange between the two phases is controlled by the synergistic effect of the total contact area and the temperature difference between the two phases. Results also demonstrate that meaningful scaling of interactions between the two phases may not be possible due to the complexity of the couplings between the dynamic and thermal parameters of the problem.

Andac, M. Gurhan; Egolfopoulos, Fokion N.; Campbell, Charles S.; Lauvergne, Romain; Wu, Ming-Shin (Technical Monitor)

2000-01-01

401

Serial dilutions: a new area of research for animal behavior.  

PubMed

This paper attempts to stimulate the psychological investigation of homeopathy and serially agitated dilutions. The history of homeopathy and serial dilutions is provided in a literature review of selected research areas. Two original illustrative experiments are also presented and discussed. The first examined the effect of serially agitated dilutions of Sevin on the mortality rate of honey bees (Apis mellifera). In a second experiment, the effect of serially agitated dilutions of sucrose on proboscis extension in honey bees was assessed. No differences were found between serially agitated dilutions of pesticides and sucrose compared with dilutions alone. Implications, limitations, and proposed further work are discussed. PMID:23234091

Nolf, Sondra L; Craig, David Philip Arthur; Abramson, Charles I

2012-10-01

402

On the various forms of the energy equation for a dilute, monatomic mixture of nonreacting gases  

NASA Technical Reports Server (NTRS)

In the case of gas mixtures, the governing equations become rather formidable and a complete listing of the equations in their various forms and methods to evaluate the transport coefficients is difficult to find. This paper seeks to compile common, as well as less well known, results in a single document. Various relationships between equations describing conservation of energy for a dilute, monatomic, nonreacting gas in local equilibrium are provided. The gas is treated as nonrelativistic, not subject to magnetic or electric fields, or radiative effects.

Kennedy, Christopher A.

1994-01-01

403

Determination of Vinyl Chloride at ug/l. Level in Water by Gas Chromatography  

ERIC Educational Resources Information Center

A quantitative method for the determination of vinyl chloride in water is presented. Vinyl chloride is transfered to the gas phase by bubbling inert gas through the water. After concentration on silica gel or Carbosieve-B, determination is by gas chromatography. Confirmation of vinyl chloride is by gas chromatography-mass spectrometry. (Author/BT)

Bellar, Thomas A.; And Others

1976-01-01

404

Production of Oxygen Gas and Liquid Metal by Electrochemical Decomposition of Molten Iron Oxide  

E-print Network

Molten oxide electrolysis (MOE) is the electrolytic decomposition of a metal oxide, most preferably into liquid metal and oxygen gas. The successful deployment of MOE hinges upon the existence of an inert anode capable of ...

Wang, Dihua

405

Inert electrode composition having agent for controlling oxide growth on electrode made therefrom  

DOEpatents

An improved inert electrode composition is suitable for use as an inert electrode in the production of metals such as aluminum by the electrolytic reduction of metal oxide or metal salt dissolved in a molten salt bath. The composition comprises one or more metal alloys and metal compounds which may include oxides of the metals comprising the alloy. The alloy and metal compounds are interwoven in a network which provides improved electrical conductivity and mechanical strength while preserving the level of chemical inertness necessary for such an electrode to function satisfactorily. The electrode composition further includes a metal compound dopant which will aid in controlling the thickness of a protective oxide layer on at least the bottom portion of an electrode made therefrom during use. 12 figs.

Ray, S.P.

1986-04-15

406

iFit and Light Dilution: Ultraviolet volcanic SO2 measurements under the microscope  

NASA Astrophysics Data System (ADS)

Volcanic SO2 flux measurement systems are a staple of volcano monitoring networks, as this volcanic gas flux reflects the magma input rate into the volcano's feeding system. SO2 flux monitoring has been used since the seventies, with some notable successes at Pinatubo, Mt. St. Helens, Montserrat and Italian volcanoes. However, there are some subtle aspects of the atmospheric radiative transfer processed inherent in the technique which have been ignored for many years; or perhaps better, they have been forgotten, as these subtleties were clearly spelt out in early COSPEC papers by Millán and co-workers. Recent work by Kern et al. (2010, 2012) has re-focussed attention on the light dilution effect during SO2 plume measurements. This occurs when solar radiation is scattered into the slant column observed by a UV spectrometer or imaging system below the height of the volcanic plume, such that it has not passed through the plume. This below-plume light dilutes the SO2 absorption produced by light passing through the plume from above, apparently reducing the amount of SO2 present. Fortunately, the light dilution process leaves a signature in the shape of the SO2 absorption spectrum, due to the non-linear behaviour of absorption lines with respect to gas amount, following the Beer-Lamber law. This signature can be used to quantify the magnitude of the light dilution in real field spectra. We developed a new intensity spectrum UV fitting code called iFit that allows fitting of the light dilution signature, and applied this to examples from Stromboli and Etna. here we summarise the results from these studies and highlight the importance of this previously ignored process for quantify SO2 gas emissions from volcanoes.

Burton, Michael; Sawyer, Georgina

2013-04-01

407

Constraining Inert Triplet dark matter by the LHC and FermiLAT  

NASA Astrophysics Data System (ADS)

We study collider phenomenology of inert triplet scalar dark matter at the LHC. We discuss possible decay of Higgs boson to dark matter candidate and apply current experimental data for invisible Higgs decay and R?? to constrain parameter space of our model. We also investigate constraints on dark matter coming from forthcoming measurement, RZ? and mono-Higgs production. We analytically calculate the annihilation cross section of dark matter candidate into 2? and Z? and then use FermiLAT data to put constraints on parameter space of Inert Triplet Model. We found that this limit can be stronger than the constraints provided by LUX experiment for low mass DM.

Yaser Ayazi, Seyed; Mahdi Firouzabadi, S.

2014-11-01

408

A steam inerting system for hydrogen disposal for the Vandenberg Shuttle  

NASA Technical Reports Server (NTRS)

A two-year feasibility and test program to solve the problem of unburned confined hydrogen at the Vandenberg Space Launch Complex Six (SLC-6) during Space Shuttle Main Engine (SSME) firings is discussed. A novel steam inerting design was selected for development. Available sound suppression water is superheated to flash to steam at the duct entrance. Testing, analysis, and design during 1987 showed that the steam inerting system (SIS) solves the problem and meets other flight-critical system requirements. The SIS design is complete and available for installation at SLC-6 to support shuttle or derivative vehicles.

Belknap, Stuart B.

1988-01-01

409

Three extra mirror or sequential families: case for a heavy Higgs boson and inert doublet.  

PubMed

We study the possibility of the existence of extra fermion families and an extra Higgs doublet. We find that requiring the extra Higgs doublet to be inert leaves space for three extra families, allowing for mirror fermion families and a dark matter candidate at the same time. The emerging scenario is very predictive: It consists of a standard model Higgs boson, with a mass above 400 GeV, heavy new quarks between 340 and 500 GeV, light extra neutral leptons, and an inert scalar with a mass below M(Z). PMID:21668143

Martínez, Homero; Melfo, Alejandra; Nesti, Fabrizio; Senjanovi?, Goran

2011-05-13

410

40 CFR 1065.340 - Diluted exhaust flow (CVS) calibration.  

Code of Federal Regulations, 2013 CFR

... Diluted exhaust flow (CVS) calibration...AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING...and Verifications Flow-Related Measurements...recommend selecting CVS flow rates in a random...background in the dilution air at the...

2013-07-01

411

40 CFR 1065.340 - Diluted exhaust flow (CVS) calibration.  

Code of Federal Regulations, 2012 CFR

... Diluted exhaust flow (CVS) calibration...AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING...and Verifications Flow-Related Measurements...recommend selecting CVS flow rates in a random...background in the dilution air at the...

2012-07-01

412

Dilute nanoemulsions via separation of satellite droplets.  

PubMed

A facile method is suggested for fabrication of dilute nanoemulsions. In a typical emulsification process, drops are usually accompanied by off-grade satellite droplets. The size of these satellite droplets ranges from hundreds of nanometers to above microns. Experiments were carried out to assess the possibility of separation of nanodrops from macroemulsions made via a conventional method in order to produce nanoemulsions. A low-power homogenizer was used to produce parent emulsions which were then injected from the bottom to a glass column containing water and allowed to cream. By monitoring drops remaining in the bottom of the column, it is clearly shown how progressively smaller they become with time yielding eventually dilute nanoemulsions. The average diameter of drops reduced to 100 nm when oil with high viscosity was used. The concentration of resulting nanoemulsions increased with increasing viscosity and ratio of the disperse phase of parent emulsions. PMID:23830283

Deen, Shad; Sajjadi, Shahriar

2013-10-01

413

Unstable blast shocks in dilute granular flows.  

PubMed

Shocks and blasts can be readily obtained in granular flows be they dense or dilute. Here, by examining the propagation of a blast shock in a dilute granular flow, we show that such a front is unstable with respect to transverse variations of the density of grains. This instability has a well-defined wavelength which depends on the density of the medium and has an amplitude which grows as an exponential of the distance traveled. These features can be understood using a simple model for the shock front, including dissipation which is inherent to granular flows. While this instability bears much resemblance to that anticipated in gases, it is distinct and has special features we discuss here. PMID:23767525

Boudet, J F; Kellay, H

2013-05-01

414

Unstable blast shocks in dilute granular flows  

NASA Astrophysics Data System (ADS)

Shocks and blasts can be readily obtained in granular flows be they dense or dilute. Here, by examining the propagation of a blast shock in a dilute granular flow, we show that such a front is unstable with respect to transverse variations of the density of grains. This instability has a well-defined wavelength which depends on the density of the medium and has an amplitude which grows as an exponential of the distance traveled. These features can be understood using a simple model for the shock front, including dissipation which is inherent to granular flows. While this instability bears much resemblance to that anticipated in gases, it is distinct and has special features we discuss here.

Boudet, J. F.; Kellay, H.

2013-05-01

415

Computational Modelling of Particle Degradation in Dilute Phase Pneumatic Conveyors  

E-print Network

Computational Modelling of Particle Degradation in Dilute Phase Pneumatic Conveyors P. Chapellea degradation during dilute phase pneumatic conveying. A numerical procedure, based on a matrix representation. A complete model of particle degradation during dilute phase pneumatic conveying is then described, where

Christakis, Nikolaos

416

21 CFR 172.710 - Adjuvants for pesticide use dilutions.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 true Adjuvants for pesticide use dilutions. 172.710 Section...Additives § 172.710 Adjuvants for pesticide use dilutions. The following surfactants...related adjuvants may be safely added to pesticide use dilutions by a grower or...

2010-04-01

417

21 CFR 172.710 - Adjuvants for pesticide use dilutions.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Adjuvants for pesticide use dilutions. 172.710 Section...Additives § 172.710 Adjuvants for pesticide use dilutions. The following surfactants...related adjuvants may be safely added to pesticide use dilutions by a grower or...

2011-04-01

418

Gas arc constriction for plasma arc welding  

NASA Technical Reports Server (NTRS)

A welding torch for plasma arc welding apparatus has an inert gas applied circumferentially about the arc column externally of the constricting nozzle so as to apply a constricting force on the arc after it has exited the nozzle orifice and downstream of the auxiliary shielding gas. The constricting inert gas is supplied to a plenum chamber about the body of the torch and exits through a series of circumferentially disposed orifices in an annular wall forming a closure at the forward end of the constricting gas plenum chamber. The constricting force of the circumferential gas flow about the arc concentrates and focuses the arc column into a more narrow and dense column of energy after exiting the nozzle orifice so that the arc better retains its energy density prior to contacting the workpiece.

McGee, William F. (Inventor); Rybicki, Daniel J. (Inventor)

1994-01-01

419

Superparamagnetism and Exchange Anisotropy in Microparticles of Magnetite Embedded in an Inert Carbonaceous Matrix  

Microsoft Academic Search

By the controlled thermal degradation of ferricinium nitrate a material composed of iron oxide particles embedded in an inert carbonaceous matrix was obtained. The iron oxide particles were found to be mostly magnetite, and their average diameter about 35 Å. This value was obtained from both x-ray diffraction line broadening and from static magnetic measurements. The small particle size caused

Shaul M. Aharoni; Morton H. Litt

1971-01-01

420

Inert Doublet Dark Matter with an additional scalar singlet and 125 GeV Higgs Boson  

E-print Network

In this work we consider a model for particle dark matter where an extra inert Higgs doublet and an additional scalar singlet is added to the Standard Model (SM) Lagrangian. The dark matter candidate is obtained from only the inert doublet. The stability of this one component dark matter is ensured by imposing a $Z_2$ symmetry on this additional inert doublet. The additional singlet scalar has a vacuum expectation value (VEV) and mixes with the Standard Model Higgs doublet resulting in two CP even scalars $h_1$ and $h_2$. We treat one of these scalars, $h_1$, to be consistent with the SM Higgs like boson of mass around 125 GeV reported by the LHC experiment. These two CP even scalars affect the annihilation cross-section of this inert doublet dark matter resulting in a larger dark matter mass region that satisfies the observed relic density. We also investigate the $h_1 \\rightarrow \\gamma\\gamma$ and $h_1 \\rightarrow \\gamma Z$ processes and compared these with LHC results. This is also used to constrain the da...

Banik, Amit Dutta

2014-01-01

421

40 CFR 174.705 - Inert ingredients from sexually compatible plant.  

Code of Federal Regulations, 2010 CFR

...exempt if all of the following conditions are met: (a) The genetic material that encodes the inert ingredient or leads to the...sexually compatible with the recipient food plant. (b) The genetic material has never been derived from a source that is...

2010-07-01

422

Section 3. Reactor physics studies 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 coeÅcient, the moderator void coeÅcient 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

423

Method, Philosophy of Education and the Sphere of the Practico-Inert  

ERIC Educational Resources Information Center

This essay discusses a conception of the relation of philosophy to education that has come to be widely held in both general philosophy and philosophy of education. This view is approached here through the employment of Jean-Paul Sartre's notion of the "practico-inert" as the realm of consolidated social objects, part of which is the institution…

Papastephanou, Marianna

2009-01-01

424

Burnup simulations and spent fuel characteristics of ZrO2 based inert matrix fuels  

Microsoft Academic Search

Reducing the inventory of long lived isotopes that are contained in spent nuclear fuel is essential for maximizing repository capacity and extending the lifetime of related storage. Because of their non-fertile matrices, inert matrix fuels (IMF's) could be an ideal vehicle for using light-water reactors to help decrease the inventory of plutonium and other transuranics (neptunium, americium, curium) that are

E. A. Schneider; M. R. Deinert; S. T. Herring; K. B. Cady

2007-01-01

425

Improved scaling laws for stage inert mass of space propulsion systems. Volume 1: Summary  

NASA Technical Reports Server (NTRS)

Summarized is a study which satisfies the need for improved scaling laws for stage inert mass of space propulsion systems. The resulting laws are applicable to current and future vehicle systems and designs for a comprehensive spectrum of anticipated planetary missions.

1971-01-01

426

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

Microsoft Academic Search

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

D. Bharathan; J. Althof

1984-01-01

427

Method of Converting Nuclear-Fuel Wastes to an Inert Solid.  

National Technical Information Service (NTIS)

This patent application concerns predominantly sodium-containing nuclear-fuel wastes, either in liquid or solid form, which are converted to an inert solid material by adding a slight excess with respect to the formation of albite (Na2O . Al2O3 . 6SiO2) o...

J. R. Berreth

1974-01-01

428

The ethics of placebo-controlled trials: a comparison of inert and active placebo controls.  

PubMed

Because of the recent and controversial example of sham surgery for the evaluation of fetal tissue transplants for Parkinson's disease, there is renewed interest in the ethics of using "active" placebos in surgical trials, where otherwise there are no inert procedures available, and in pharmacological trials, where there are inert substances, but where patients may guess to which arm they have been allocated. This paper seeks to clarify the ethical arguments surrounding the use of active placebos in trials, and to set up a notation for assessing the ethics of trials more generally. We first establish an framework by which ethics committees can analyze such trials. We examine (1) the scientific value of the research; (2) the expected risks and benefits to individual patients, and (3) the voluntary nature of consent. We then contrast the implications of this framework for inert and active placebo-controlled trials, respectively. In particular, we analyze their relative expected utility using three main utility factors, namely, treatment effects, placebo effects, and altruism. We conclude that, when the intervention is already widely available, active placebo trials rely more heavily on altruism than do inert placebo trials and, when the intervention is restricted, this excess reliance may not be needed. What our analysis provides is the explicit justification for the apparent caution of Institutional Review Boards or ethics committees when reviewing sham operations, especially when the expected harm is not trivial and the risk of exploitation is high. PMID:15827854

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

2005-05-01

429

YOUNG INFANTS' REASONING ABOUT PHYSICAL EVENTS INVOLVING INERT AND SELF-PROPELLED OBJECTS  

PubMed Central

The present research examined whether 5- to 6.5-month-old infants would hold different expectations about various physical events involving a box after receiving evidence that it was either inert or self-propelled. Infants were surprised if the inert but not the self-propelled box: reversed direction spontaneously (Experiment 1); remained stationary when hit or pulled (Experiments 3 and 3A); remained stable when released in midair or with inadequate support from a platform (Experiment 4); or disappeared when briefly hidden by one of two adjacent screens (the second screen provided the self-propelled box with an alternative hiding place; Experiment 5). On the other hand, infants were surprised if the inert or the self-propelled box appeared to pass through an obstacle (Experiment 2) or disappeared when briefly hidden by a single screen (Experiment 5). The present results indicate that infants as young as 5 months of age distinguish between inert and self-propelled objects and hold different expectations for physical events involving these objects, even when incidental differences between the objects are controlled. These findings are consistent with the proposal by Gelman (1990), Leslie (1994), and others that infants endow self-propelled objects with an internal source of energy. Possible links between infants’ concepts of self-propelled object, agent, and animal are also discussed. PMID:19232579

Luo, Yuyan; Kaufman, Lisa; Baillargeon, Renee

2009-01-01

430

Quantification of Pantothenic Acid and Folates by Stable Isotope Dilution Assays  

Microsoft Academic Search

Stable isotope dilution assays for the quantification of pantothenic acid and folates in foods by using four-fold labeled isotopomers of the vitamins as internal standards (IS) were developed. The use of labeled IS enabled to exactly correct losses during cleanup and derivatization.Pantothenic acid and its labeled isotopomer were detected as trimethylsilyl derivatives by gas chromatography–mass spectrometry. In starch a detection

Michael Rychlik; Achim Freisleben

2002-01-01

431

Quantification of Orotic Acid in Dried Filter-Paper Urine Samples by Stable Isotope Dilution  

Microsoft Academic Search

A rapid, sensitive, and specific method for quantification of orotic acid from dried filter-paper urine samples is described. The method involves stable isotope dilution with 1,3-(15N2)orotic acid and analysis by gas chroma- tography-mass spectrometry. The assay is sufficiently sensitive to be used with solvent extraction techniques commonly used for urinary organic acid analysis. Extrac- tion efficiencies of both native and

Mark T. McCann; Mark M. Thompson; Joni C. Gueron; Mendel Tuchman

432

Effect of Hydrogen Dilution of Silane in Hydrogenated Amorphous Silicon Films Prepared by Photochemical Vapor Deposition  

Microsoft Academic Search

Hydrogenated amorphous silicon (a-Si:H) films were prepared by mercury photosensitized decomposition of silane-hydrogen (or -helium) gas mixtures. In hydrogen dilution, a-Si:H films were deposited from 20-100% of the silane fraction and hydrogenated amorphous-microcrystalline mixed-phase silicon (muc-Si:H) films were deposited for less than 10% of the silane fraction. The Si-H2 bond density and optical gap for a-Si:H films increased upon decreasing

Takaaki Kamimura; Masahiko Hirose

1986-01-01

433

Effect of Dilution Rate on Metabolic Pathway Shift between Aceticlastic and Nonaceticlastic Methanogenesis in Chemostat Cultivation  

Microsoft Academic Search

Acetate conversion pathways of methanogenic consortia in acetate-fed chemostats at dilution rates of 0.025 and 0.6 day1 were investigated by using 13C-labeled acetates, followed by gas chromatography-mass spectrom- etry (GC-MS) analysis of the CH4 and CO2 produced. Nonaceticlastic syntrophic oxidation by acetate-oxidizing syntrophs and hydrogenotrophic methanogens was suggested to occupy a primary pathway (approximately 62 to 90%) in total methanogenesis

Toru Shigematsu; Yueqin Tang; Tsutomu Kobayashi; Hiromi Kawaguchi; Shigeru Morimura; Kenji Kida

2004-01-01

434

A quadrature-based moment method for dilute fluid-particle flows  

Microsoft Academic Search

Gas-particle and other dispersed-phase flows can be described by a kinetic equation containing terms for spatial transport, acceleration, and particle processes (such as evaporation or collisions). In principle, the kinetic description is valid from the dilute (non-collisional) to the dense limit. However, its numerical solution in multi-dimensional systems is intractable due to the large number of independent variables. As an

O. Desjardins; R. O. Fox; P. Villedieu

2008-01-01

435

A level set approach for dilute non-collisional fluid-particle flows  

Microsoft Academic Search

Gas-particle and other dispersed-phase flows can be described by a kinetic equation containing terms for spatial transport, acceleration, and particle processes (such as evaporation or collisions). However, computing the dispersed velocity is a challenging task due to the large number of independent variables. A level set approach for computing dilute non-collisional fluid-particle flows is presented. We will consider the sprays

Hailiang Liu; Zhongming Wang; Rodney O. Fox

2011-01-01

436

Adiabatic premixed combustion in a gaseous fuel porous inert media under high pressure and temperature: Novel flame stabilization technique  

Microsoft Academic Search

This work presents an experimental investigation to study the characteristics of combustion using a premixed methane–air mixture within a non-homogeneous porous inert medium (PIM) under high pressure and temperature. In order to obtain a stable flame under these operating conditions within PIM, a novel flame stabilization technique in porous inert media (PIM) combustion under high pressure and temperature has been

Ayman Bakry; Ahmed Al-Salaymeh; Ala’a H. Al-Muhtaseb; Ahmad Abu-Jrai; D. Trimis

2011-01-01

437

Gas flow effects on selective laser melting (SLM) manufacturing performance  

Microsoft Academic Search

This study has been designed to investigate the effect of inert gas flow within the selective laser melting (SLM) process and the effects induced by this gas flow on the reproducibility of the key attributes (porosity and compression strength) created in the construction of porous titanium components. The work quantifies the characteristics of the manufactured parts and relates results of

B. Ferrar; L. Mullen; E. Jones; R. Stamp; C. J. Sutcliffe

438

Ultrasmall particles of CdSe and CdS formed in nafion by an ion-dilution technique  

SciTech Connect

The transition of semiconductor chalcogenides from molecular CdX (X = Se, S) to bulk material has been observed in Nafion, a cation-exchange membrane. The two-phase structure of Nafion, consisting of a hydrophobic region and ionic clusters, has been utilized to form ultrasmall particles of CdS/Se by using a technique analogous to an inverted micelle microemulsion method, where the Cd ion/ionomer cluster ratio is controlled by diluting the cadmium-exchange solution with an inert ion (Ca{sup 2+}). The absorption onset for the cadmium chalcogenides formed ban be tuned over a range of more than 3.5 eV by varying the Cd{sup 2+}Ca{sup 2+} ratio in the solution used to exchange the acidic form of the ionomer membrane.

Smotkin, E.S.; Brown, R.M. Jr.; Rabenberg, L.K.; Salomon, K.; Bard, A.J.; Campion, A.; Fox, M.A.; Mallouk, T.E.; Webber, S.E.; White, J.M. (Univ. of Texas, Austin (USA))

1990-09-20

439

The Effect of Dilution on the Structure of Microbial Communities  

NASA Technical Reports Server (NTRS)

To determine how dilution of microbial communities affects the diversity of the diluted assemblage a series of numerical simulations were conducted that determined the theoretical change in diversity, richness, and evenness of the community with serial dilution. The results of the simulation suggested that the effects are non linear with a high degree of dependence on the initial evenness of the community being diluted. A series of incubation experiments using a range of dilutions of raw sewage as an inoculum into sterile sewage was used for comparison to the simulations. The diluted communities were maintained in batch fed reactors (three day retention time) for nine days. The communities were harvested and examined by conventional plating and by molecular analysis of the whole-community DNA using AFLP and T-RFLP. Additional, CLPP analysis was also applied. The effects on richness predicted by the numerical simulations were confirmed by the analyses used. The diluted communities fell into three groups, a low dilution, intermediate dilution, and high dilution group, which corresponded well with the groupings obtained for community richness in simulation. The grouping demonstrated the non-linear nature of dilution of whole communities. Furthermore, the results implied that the undiluted community consisted of a few dominant types accompanied by a number of rare (low abundance) types as is typical in unevenly distributed communities.

Mills, Aaron L.

2000-01-01

440

Reactions of gaseous, elemental mercury with dilute halogen solutions  

SciTech Connect

Of the trace elements known to exist in fossil fuels, mercury (Hg) has emerged as one of the greatest concerns. Mercury has been found to be emitted from combustion in at least two different chemical forms: elemental Hg and oxidized Hg compounds. Precise identification of the oxidized compounds emitted has not been accomplished to date. However, most workers in this field assume that mercuric chloride should be the predominant oxidized species. Mercuric chloride should be readily removed in a wet scrubber system because of its relatively high solubility in water. However, it has been presumed, and we have shown, that elemental Hg will pass through a wet scrubber system with little or no removal being effected. Therefore, it is important, in order to obtain a high total Hg removal, to study methods that might result in a removal of gaseous, elemental Hg from a flue-gas stream. In this regard, we have been studying the effect of dilute halogen-containing solutions on elemental Hg in gas streams of various compositions. In particular, the results of passing Hg through bubblers containing solutions of iodine, chlorine, and chloric acid are described. Mercury found in the bubbler solutions is an indication of the extent of reaction (oxidation) of elemental Hg with the halogen species, since we have found very little Hg transferred to the liquid phase when only distilled water is used in the bubblers. Results using commercial iodine, sodium hypochlorite, and NOXSORB (sup TM) solutions are presented and discussed.

Mendelsohn, M.H.; Livengood, C.D.

1996-07-01

441

Inhibition of oil plume dilution in Langmuir ocean circulation  

NASA Astrophysics Data System (ADS)

Oil spills from deep-water blowouts rise through and interact with the ocean mixed layer and Langmuir turbulence, leading to considerable diversity of oil slick dilution patterns observed on the ocean surface. Certain conditions can drive oil droplet plumes to organize into distinct bands called windrows, inhibiting oil dilution. Observations of blurred or even diffused plumes are also common, but conditions under which these various dilution regimes emerge are not well understood. Here we use large eddy simulations to explain and quantify the dilution patterns and their dependence on relevant physical parameters. Two mechanisms, the downwelling and dilution due to Langmuir cells and the inhibition of dilution due to buoyancy of oil droplets, compete. This competition can be characterized by the ratio of Stokes drift to droplet rise velocity—the drift-to-buoyancy parameter, Db. We find that plume appearance and quantitative measures of relative dilution depend mainly on Db.

Yang, Di; Chamecki, Marcelo; Meneveau, Charles

2014-03-01

442

The rheology of a semi-dilute suspension of swimming model micro-organisms  

NASA Astrophysics Data System (ADS)

The rheological properties of a cell suspension may play an important role in the flow field generated by populations of swimming micro-organisms (e.g. in bioconvection). In this paper, a swimming micro-organism is modelled as a squirming sphere with prescribed tangential surface velocity, in which the centre of mass of the sphere may be displaced from the geometric centre (bottom-heaviness). Effects of inertia and Brownian motion are neglected, because real micro-organisms swim at very low Reynolds numbers but are too large for Brownian effects to be important. The three-dimensional movement of 64 identical squirmers in a simple shear flow field, contained in a cube with periodic boundary conditions, is dynamically computed, for random initial positions and orientations. The computation utilizes a database of pairwise interactions that has been constructed by the boundary element method. The restriction to pairwise additivity of forces is expected to be justified if the suspension is semi-dilute. The results for non-bottom-heavy squirmers show that the squirming does not have a direct influence on the apparent viscosity. However, it does change the probability density in configuration space, and thereby causes a slight decrease in the apparent viscosity at O(c2), where c is the volume fraction of spheres. In the case of bottom-heavy squirmers, on the other hand, the stresslet generated by the squirming motion directly contributes to the bulk stress at O(c), and the suspension shows strong non-Newtonian properties. When the background simple shear flow is directed vertically, the apparent viscosity of the semi-dilute suspension of bottom-heavy squirmers becomes smaller than that of inert spheres. When the shear flow is horizontal and varies with the vertical coordinate, on the other hand, the apparent viscosity becomes larger than that of inert spheres. In addition, significant normal stress differences appear for all relative orientations of gravity and the shear flow, in the case of bottom-heavy squirmers.

Ishikawa, Takuji; Pedley, T. J.

443

Dilution jet mixing program, phase 3  

NASA Technical Reports Server (NTRS)

The main objectives for the NASA Jet Mixing Phase 3 program were: extension of the data base on the mixing of single sided rows of jets in a confined cross flow to discrete slots, including streamlined, bluff, and angled injections; quantification of the effects of geometrical and flow parameters on penetration and mixing of multiple rows of jets into a confined flow; investigation of in-line, staggered, and dissimilar hole configurations; and development of empirical correlations for predicting temperature distributions for discrete slots and multiple rows of dilution holes.

Srinivasan, R.; Coleman, E.; Myers, G.; White, C.

1985-01-01

444

Structure and stability of vortices in dilute Bose-Einstein condensates at ultralow temperatures.  

PubMed

We compute the structure of a quantized vortex line in a harmonically trapped dilute atomic Bose-Einstein condensate using the Popov version of the Hartree-Fock-Bogoliubov mean-field theory. The vortex is shown to be (meta)stable in a nonrotating trap even in the zero-temperature limit, thus confirming that weak particle interactions induce for the condensed gas a fundamental property characterizing "classical" superfluids. We present the structure of the vortex at ultralow temperatures and discuss the crucial effect of the thermal gas component to its energetic stability. PMID:11290019

Virtanen, S M; Simula, T P; Salomaa, M M

2001-03-26

445

Dilute Potts model in two dimensions  

NASA Astrophysics Data System (ADS)

We study the two-dimensional dilute q -state Potts model by means of transfer-matrix and Monte Carlo methods. Using the random-cluster representation, we include noninteger values of q . We locate phase transitions in the three-dimensional parameter space of q , the Potts coupling K?0 , and the chemical potential of the vacancies. The critical plane is found to contain a line of fixed points that divides into a critical branch and a tricritical one, just as predicted by the renormalization scenario formulated by Nienhuis for the dilute Potts model. The universal properties along the line of fixed points agree with the theoretical predictions. We also determine the density of the vacancies along these branches. For q=2-2 we obtain the phase diagram in a three-dimensional parameter space that also includes a coupling V?0 between the vacancies. For q=2 , the latter space contains the Blume-Capel model as a special case. We include a determination of the tricritical point of this model, as well as an analysis of percolation clusters constructed on tricritical Potts configurations for noninteger q . This percolation study is based on Monte Carlo algorithms that include local updates flipping between Potts sites and vacancies. The bond updates are performed locally for q<1 and by means of a cluster algorithm for q>1 . The updates for q>1 use a number of operations per site independent of the system size.

Qian, Xiaofeng; Deng, Youjin; Blöte, Henk W. J.

2005-11-01

446

Geometric Exponents of Dilute Loop Models  

NASA Astrophysics Data System (ADS)

The fractal dimensions of the hull, the external perimeter and of the red bonds are measured through Monte Carlo simulations for dilute minimal models, and compared with predictions from conformal field theory and SLE methods. The dilute models used are those first introduced by Nienhuis. Their loop fugacity is ?=-2 \\cos(?/bar{kappa}) where the parameter bar{kappa} is linked to their description through conformal loop ensembles. It is also linked to conformal field theories through their central charges c(bar{kappa})=13-6(bar{kappa}+bar{kappa}^{-1}) and, for the minimal models of interest here, bar{kappa}=p/p' where p and p' are two coprime integers. The geometric exponents of the hull and external perimeter are studied for the pairs ( p, p')=(1,1),(2,3),(3,4),(4,5),(5,6),(5,7), and that of the red bonds for ( p, p')=(3,4). Monte Carlo upgrades are proposed for these models as well as several techniques to improve their speeds. The measured fractal dimensions are obtained by extrapolation on the lattice size H, V??. The extrapolating curves have large slopes; despite these, the measured dimensions coincide with theoretical predictions up to three or four digits. In some cases, the theoretical values lie slightly outside the confidence intervals; explanations of these small discrepancies are proposed.

Provencher, Guillaume; Saint-Aubin, Yvan; Pearce, Paul A.; Rasmussen, Jørgen

2012-04-01

447

ANALYSIS OF BORON DILUTION TRANSIENTS IN PWRS.  

SciTech Connect

A study has been carried out with PARCS/RELAP5 to understand the consequences of hypothetical boron dilution events in pressurized water reactors. The scenarios of concern start with a small-break loss-of-coolant accident. If the event leads to boiling in the core and then the loss of natural circulation, a boron-free condensate can accumulate in the cold leg. The dilution event happens when natural circulation is re-established or a reactor coolant pump (RCP) is restarted in violation of operating procedures. This event is of particular concern in B&W reactors with a lowered-loop design and is a Generic Safety Issue for the U.S. Nuclear Regulatory Commission. The results of calculations with the reestablishment of natural circulation show that there is no unacceptable fuel damage. This is determined by calculating the maximum fuel pellet enthalpy, based on the three-dimensional model, and comparing it with the criterion for damage. The calculation is based on a model of a B&W reactor at beginning of the fuel cycle. If an RCP is restarted, unacceptable fuel damage may be possible in plants with sufficiently large volumes of boron-free condensate in the cold leg.

DIAMOND,D.J.BROMLEY,B.P.ARONSON,A.L.

2004-02-04

448

Investigation factors that control trace metal toxicity in coastal systems : a temporal and spatial analysis of kinetically inert copper in Boston Harbor  

E-print Network

(cont.) form of inert Cu. Correlations between Cu concentrations and total suspended solids at one sampling location suggested that sediment resuspension may be a source of inert Cu to coastal waters. Consistently significant ...

Fitzmaurice, Arthur G., 1980-

2004-01-01

449

Motor-mediated microtubule self-organization in dilute and semi-dilute filament solutions.  

SciTech Connect

We study molecular motor-induced microtubule self-organization in dilute and semi-dilute filament solutions. In the dilute case, we use a probabilistic model of microtubule interaction via molecular motors to investigate microtubule bundle dynamics. Microtubules are modeled as polar rods interacting through fully inelastic, binary collisions. Our model indicates that initially disordered systems of interacting rods exhibit an orientational instability resulting in spontaneous ordering. We study the existence and dynamic interaction of microtubule bundles analytically and numerically. Our results reveal a long term attraction and coalescing of bundles indicating a clear coarsening in the system; microtubule bundles concentrate into fewer orientations on a slow logarithmic time scale. In semi-dilute filament solutions, multiple motors can bind a filament to several others and, for a critical motor density, induce a transition to an ordered phase with a nonzero mean orientation. Motors attach to a pair of filaments and walk along the pair bringing them into closer alignment. We develop a spatially homogenous, mean-field theory that explicitly accounts for a force-dependent detachment rate of motors, which in turn affects the mean and the fluctuations of the net force acting on a filament. We show that the transition to the oriented state can be both continuous and discontinuous when the force-dependent detachment of motors is important.

Swaminathan, S.; Ziebert, F.; Aranson, I. S.; Karpeev, D. (Mathematics and Computer Science); ( MSD); (Northwestern Univ.); (UMR CNRS)

2011-01-01

450

Adsorption of inert gases including element 118 on noble metal and inert surfaces from ab initio Dirac-Coulomb atomic calculations  

NASA Astrophysics Data System (ADS)

The interaction of the inert gases Rn and element 118 with various surfaces has been studied on the basis of fully relativistic ab initio Dirac-Coulomb CCSD(T) calculations of atomic properties. The calculated polarizability of element 118, 46.3 a.u., is the largest in group 18, the ionization potential is the lowest at 8.91 eV, and the estimated atomic radius is the largest, 4.55 a.u. These extreme values reflect, in addition to the general trends in the Periodic Table, the relativistic expansion and destabilization of the outer valence 7p3/2 orbital. Van der Waals coefficients C3 and adsorption enthalpies ?Hads of Ne through element 118 on noble metals and inert surfaces, such as quartz, ice, Teflon, and graphite, were calculated in a physisorption model using the atomic properties obtained. The C3 coefficients were shown to steadily increase in group 18, while the increase in ?Hads from Ne to Rn does not continue to element 118: The large atomic radius of the latter element is responsible for a decrease in the interaction energy. We therefore predict that experimental distinction between Rn and 118 by adsorption on these types of surfaces will not be feasible. A possible candidate for separating the two elements is charcoal; further study is needed to test this possibility.

Pershina, V.; Borschevsky, A.; Eliav, E.; Kaldor, U.

2008-10-01

451

Uninhibited methane biogeochemistry: A candid view of interactions among soil processes made possible by stable isotope and inert tracers  

NASA Astrophysics Data System (ADS)

Methane emission emerges as a highly variable property of ecosystems because the proximate controlling processes, methane production, consumption and transport, appear to vary considerably in both space and time. But the extent and importance of any co-correlation among these processes remains unclear. The idea of co-correlation is supported by a simplified model of methane fluxes that we have developed and by the frequently-observed relationship between net ecosystem productivity and methane emission. Yet the dominant approach toward problems in methane biogeochemistry remains focused on measuring or modeling each process individually and then assembling them into an understanding of the whole. This approach has arisen, in part, from our historic inability to measure methane production, consumption and transport simultaneously. Instead, one or more processes have been inhibited or excluded from consideration, leading to an incomplete picture of soil methane biogeochemistry. To overcome this limitation, we have used additions of 13C- labeled methane to simultaneously measure methane production and consumption in wetland soils. When coupled with additions of inert hydrologic and gas tracers (e.g., Br- and SF6), we have measured methane production, consumption and soil-atmosphere transport under field conditions with minimal disturbance. Our results reveal strong co-correlations among the processes that can be useful for building simpler, mechanistically-based models of ecosystem methane emissions.

von Fischer, J. C.

2006-12-01

452

Method and apparatus maintaining multi-component sample gas constituents in vapor phase during sample extraction and cooling  

DOEpatents

An apparatus and method for diluting and cooling that is extracted from high temperature and/or high pressure industrial processes. Through a feedback process, a specialized, CFD-modeled dilution cooler is employed along with real-time estimations of the point at which condensation will occur within the dilution cooler to define a level of dilution and diluted gas temperature that results in a gas that can be conveyed to standard gas analyzers that contains no condensed hydrocarbon compounds or condensed moisture.

Farthing, William Earl (Pinson, AL); Felix, Larry Gordon (Pelham, AL); Snyder, Todd Robert (Birmingham, AL)

2009-12-15

453

Method and apparatus for maintaining multi-component sample gas constituents in vapor phase during sample extraction and cooling  

DOEpatents

An apparatus and method for diluting and cooling that is extracted from high temperature and/or high pressure industrial processes. Through a feedback process, a specialized, CFD-modeled dilution cooler is employed along with real-time estimations of the point at which condensation will occur within the dilution cooler to define a level of dilution and diluted gas temperature that results in a gas that can be conveyed to standard gas analyzers that contains no condensed hydrocarbon compounds or condensed moisture.

Farthing, William Earl (Pinson, AL) [Pinson, AL; Felix, Larry Gordon (Pelham, AL) [Pelham, AL; Snyder, Todd Robert (Birmingham, AL) [Birmingham, AL

2008-02-12

454

Report on the treatability study for inerting small quantities of radioactive explosives and explosive components  

SciTech Connect

As a result of Sandia`s radiation hardening testing on a variety of its explosive components, radioactive waste streams were generated and have to be disposed of as radioactive waste. Due to the combined hazards of explosives and radioactivity, Sandia`s Radioactive and Mixed Waste Management organization did not have a mechanism for disposal of these waste streams. This report documents the study done to provide a method for the removal of the explosive hazard from those waste streams. The report includes the design of the equipment used, procedures followed, results from waste stream analog tests and the results from the actual explosive inerting tests on radioactive samples. As a result of the inerting treatment, the waste streams were rendered non-explosive and, thus, manageable through normal radioactive waste disposal channels.

Loyola, V.M.; Reber, S.D.

1996-02-01

455

Atomization of cadmium compounds under reactive and inert high-temperature environment with stationary sample introduction.  

PubMed

Atomization of cadmium compounds (acetate, chloride, nitrate, perchlorate, sulfate, formate, propionate) was studied using flame atomic absorption spectrometry. Our goal was to study processes influencing atomization separately, the focus was on the contribution of thermal properties of substances to atomization. For this purpose new techniques and equipment have been developed, such as a special separated three-slot burner, quartz flame furnace, and an electrically heated thermospectrometer. According to quartz flame furnace and thermospectrometric measurements, cadmium salts do not atomize below 600 °C in an inert atmosphere. We found that in the thermospectrometer the atomization of cadmium compounds follows at least two different reaction courses. At lower temperatures (650-700 °C) a slower mechanism is dominant at higher regions of the furnace, while at 800 °C a faster mechanism demanding less residence time in the furnace becomes dominant. Under inert atmosphere the degree of atomization strongly depends on the thermal properties of substances. PMID:24666943

Nagy, Dávid; Nagy, Tibor; Balogh, Attila; Falussy, Csaba; Posta, József

2014-03-01

456

Accurate determination of sulfur in gasoline and related fuel samples using isotope dilution ICP–MS with direct sample injection and microwave-assisted digestion  

Microsoft Academic Search

Inductively coupled plasma isotope-dilution mass spectrometry (ICP–IDMS) with direct injection of isotope-diluted samples into the plasma, using a direct injection high-efficiency nebulizer (DIHEN), was applied for accurate sulfur determinations in sulfur-free premium gasoline, gas oil, diesel fuel, and heating oil. For direct injection a micro-emulsion consisting of the corresponding organic sample and an aqueous 34S-enriched spike solution with additions of

Jens Heilmann; Sergei F. Boulyga; Klaus G. Heumann

2004-01-01

457

Characterization of the Dilute Ising Antiferromagnet  

SciTech Connect

A spin glass is a magnetic ground state in which ferromagnetic and antiferromagnetic exchange interactions compete, thereby creating frustration and a multidegenerate state with no long range order. An Ising system is a system where the spins are constrained to lie parallel or antiparallel to a primary axis. There has been much theoretical interest in the past ten years in the effects of applying a magnetic field transverse to the primary axis in an Ising spin glass at low temperatures and thus study phase transitions at the T=0 limit. The focus of this study is to search for and characterize a new Ising spin glass system. This is accomplished by site diluting yttrium for terbium in the crystalline material TbNi{sub 2}Ge{sub 2}. The first part of this work gives a brief overview of the physics of rare earth magnetism and an overview of experimental characteristics of spin glasses. This is followed by the methodology used to manufacture the large single crystals used in this study, as well as the measurement techniques used. Next, a summary of the results of magnetic measurements on across the dilution series from pure terbium to pure yttrium is presented. This is followed by detailed measurements on particular dilutions which demonstrate spin glass behavior. Pure TbNi{sub 2}Ge{sub 2} is an Ising antiferromagnet with a several distinct metamagnetic states below 17 K. As the terbium is alloyed with yttrium, these magnetic states are weakened in a consistent manner, as is seen in measurements of the transition temperatures and analysis of Curie-Weiss behavior at high temperature. At low concentrations of terbium, below 35%, long range order is no longer present and a spin-glass-like state emerges. This state is studied through various measurements, dc and ac susceptibility, resistivity, and specific heat. This magnetic behavior was then compared to that of other well characterized spin glasses. It is concluded that there is a region of concentration s for which a spin glass state is formed with the best spin glasses existing between the concentration of 25% and 30%.

Wiener, T.

2000-09-12

458

Phase Relations in the System Ce,O,-AI,O, in Inert and Reducing Atmospheres  

E-print Network

Phase Relations in the System Ce,O,-AI,O, in Inert and Reducing Atmospheres A. Cuneyt TasAlO,, in the system Ce,O,-AI,O, has been synthesized from the oxides and shown to have a perovskite-like tetragonalAIO,. This compound is shown to be stable up to 1950°C. The 1:11 compound, CeAI,,O,,, has also been synthesized

Tas, A. Cuneyt

459

Bomb radiocarbon in metabolically inert tissues from terrestrial and marine mammals  

SciTech Connect

We report here radiocarbon measurements of monkey eye lens nucleus proteins and a narwhal tusk, biological tissues which have sampled the bomb radiocarbon signal in different ways. The results confirm the metabolic inertness of eye lens nucleus proteins and demonstrate the feasibility of measuring radiocarbon in small samples of biological tissue using accelerator mass spectrometry (AMS). The narwhal tusk provides a unique record of the radiocarbon activity in Arctic Ocean waters over most of the 20th century.

Bada, J.L.; Vrolijk, C.D.; Brown, S.; Druffel, E.R.M.; Hedges, R.E.M.

1987-10-01

460

Burnup simulations and spent fuel characteristics of ZrO 2 based inert matrix fuels  

Microsoft Academic Search

Reducing the inventory of long lived isotopes that are contained in spent nuclear fuel is essential for maximizing repository capacity and extending the lifetime of related storage. Because of their non-fertile matrices, inert matrix fuels (IMF’s) could be an ideal vehicle for using light-water reactors to help decrease the inventory of plutonium and other transuranics (neptunium, americium, curium) that are

E. A. Schneider; M. R. Deinert; S. T. Herring; K. B. Cady

2007-01-01