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1

Automated measurement of respiratory gas exchange by an inert gas dilution technique  

NASA Technical Reports Server (NTRS)

A respiratory gas analyzer (RGA) has been developed wherein a mass spectrometer is the sole transducer required for measurement of respiratory gas exchange. The mass spectrometer maintains all signals in absolute phase relationships, precluding the need to synchronize flow and gas composition as required in other systems. The RGA system was evaluated by comparison with the Douglas bag technique. The RGA system established the feasibility of the inert gas dilution method for measuring breath-by-breath respiratory gas exchange. This breath-by-breath analytical capability permits detailed study of transient respiratory responses to exercise.

Sawin, C. F.; Rummel, J. A.; Michel, E. L.

1974-01-01

2

Inert Gas Dilution Effect on the Flammability Limits of Hydrocarbon Mixtures  

E-print Network

al. [4], and Kuchta et al. [5] through Bureau of Mines Bulletin publications. 2.3.2 ASTM methods The American Society for Testing and Materials (ASTM) adopted three closed vessel methods to measure flammability limits of gases and vapors....1 Flammability limit vs. temperature????????..??7 2.2.2 Flammability limit vs. pressure????????????8 2.2.3 Flammability limit vs. oxygen and inert gases????.?9 2.2.4 Flammability limit vs. apparatus size and shape???..?..10 2.2.5 Flammability limit vs. flame...

Zhao, Fuman

2012-02-14

3

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

4

Inert gas thrusters  

NASA Technical Reports Server (NTRS)

Inert gases, particularly argon and xenon, are of interest as possible alternatives to the usual electric thruster propellants of mercury and cesium. Hollow cathode data were obtained for a wide range of operating conditions. Some test conditions gave plasma coupling voltages at or below the sputtering threshold, hence should permit long operating lifetimes. All observations of hollow cathode operation were consistent with a single theory of operation, in which a significant amount of the total electron emission is from localized areas within the orifice. This mode of emission is also supported by scanning electron microscope photographs that indicate local temperatures at or near the melting temperature of the tungsten tip. Experimental hollow cathode performance was correlated for two orifice diameters, three inert gas propellants, and a range of flow rates for each propellant. The basic theory for the production of doubly ionized argon and xenon was completed. Experimental measurements of the doubly ionized fraction agree with theory within about plus or minus 20 percent. High voltage isolators were studied for the propellant feed line. The breakdown voltage per segment ranged from 300 to over 500 V with argon.

Kaufman, H. R.

1977-01-01

5

Inert gas ion thruster  

NASA Technical Reports Server (NTRS)

Inert gas performance with three types of 12 cm diameter magnetoelectrostatic containment (MESC) ion thrusters was tested. The types tested included: (1) a hemispherical shaped discharge chamber with platinum cobalt magnets; (2) three different lengths of the hemispherical chambers with samarium cobalt magnets; and (3) three lengths of the conical shaped chambers with aluminum nickel cobalt magnets. The best argon performance was produced by a 8.0 cm long conical chamber with alnico magnets. The best xenon high mass utilization performance was obtained with the same 8.0 cm long conical thruster. The hemispherical thruster obtained 75 to 87% mass utilization at 185 to 205 eV/ion of singly charged ion equivalent beam.

Ramsey, W. D.

1980-01-01

6

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

7

Inert gas thrusters  

NASA Technical Reports Server (NTRS)

Inert gas thrusters have continued to be of interest for space propulsion applications. Xenon is of interest in that its physical characteristics are well suited to propulsion. High atomic weight and low tankage fraction were major factors in this choice. If a large amount of propellant was required, so that cryogenic storage was practical, argon is a more economical alternative. Argon was also the preferred propellant for ground applications of thruster technology, such as sputter etching and deposition. Additional magnetic field measurements are reported. These measurements should be of use in magnetic field design. The diffusion of electrons through the magnetic field above multipole anodes was studied in detail. The data were consistent with Bohm diffusion across a magnetic field. The theory based on Bohm diffusion was simple and easily used for diffusion calculations. Limited startup data were obtained for multipole discharge chambers. These data were obtained with refractory cathodes, but should be useful in predicting the upper limits for starting with hollow cathodes.

Kaufman, H. R.

1978-01-01

8

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

Code of Federal Regulations, 2010 CFR

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

2010-07-01

9

Inert-Gas Solids with Nanoscale Porosity  

NASA Astrophysics Data System (ADS)

The structure and thermal properties of novel mesoporous inert-gas solids were studied by synchrotron x-ray diffraction. The materials were prepared by injecting a jet of helium containing dilute amounts of inert atoms and molecules (Ne, Kr, N2) into superfluid helium. The characteristic size of the constituent building blocks is ~60 Å, and the density is >~1020 impurity atoms per cm3. The Kr and N2 solids are stable outside of liquid He, up to temperatures above 10 K. These materials may find various applications as a new type of porous medium for fundamental physics, as well as in cluster physics, matrix isolation spectroscopy, and catalysis of low temperature chemical reactions.

Kiryukhin, V.; Keimer, B.; Boltnev, R. E.; Khmelenko, V. V.; Gordon, E. B.

1997-09-01

10

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

Code of Federal Regulations, 2012 CFR

...concentration reading controls the inerting or enriching system and activates...alarm and automatic shutdown...concentration reading controls the enriching system and activates...alarm and automatic shutdown...concentration reading controls the diluting system and activates...alarm and automatic...

2012-07-01

11

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

Code of Federal Regulations, 2011 CFR

...concentration reading controls the inerting or enriching system and activates...alarm and automatic shutdown...concentration reading controls the enriching system and activates...alarm and automatic shutdown...concentration reading controls the diluting system and activates...alarm and automatic...

2011-07-01

12

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

Code of Federal Regulations, 2013 CFR

...concentration reading controls the inerting or enriching system and activates...alarm and automatic shutdown...concentration reading controls the enriching system and activates...alarm and automatic shutdown...concentration reading controls the diluting system and activates...alarm and automatic...

2013-07-01

13

Mechanisms of inert gas narcosis  

NASA Technical Reports Server (NTRS)

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

1973-01-01

14

46 CFR 154.904 - Inert gas system: Controls.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Inert gas system: Controls. 154.904...VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment...Systems § 154.904 Inert gas system: Controls. The inert gas system must have:...

2010-10-01

15

46 CFR 154.903 - Inert gas systems: General.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Inert gas systems: General. 154.903...VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment...Systems § 154.903 Inert gas systems: General. (a) Inert gas carried or generated to...

2010-10-01

16

46 CFR 154.904 - Inert gas system: Controls.  

Code of Federal Regulations, 2013 CFR

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

2013-10-01

17

Inert gas effects on embryonic development.  

NASA Technical Reports Server (NTRS)

It had been found in previous investigations that hatchability of fertile chicken eggs is reduced to 50% or less of controls if incubation takes place in a low nitrogen atmosphere containing He. Although these results suggest some role for nitrogen in embryogenesis, it is possible that a requirement exists for an inert molecule closer in physical characteristics to nitrogen than is He. An investigation is conducted involving incubation at ground level pressure in a gas mixture in which the 79% inert component was either neon or argon. The effect of varying combinations of nitrogen, helium, and oxygen was also studied.

Weiss, H. S.; Grimard, M.

1972-01-01

18

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 154...Containment Systems § 154.908 Inert gas generator: Location. (a) Except as allowed...paragraph (b) of this section, an inert gas generator must be located in the main...

2010-10-01

19

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 154...Containment Systems § 154.908 Inert gas generator: Location. (a) Except as allowed...paragraph (b) of this section, an inert gas generator must be located in the main...

2012-10-01

20

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 154...Containment Systems § 154.908 Inert gas generator: Location. (a) Except as allowed...paragraph (b) of this section, an inert gas generator must be located in the main...

2013-10-01

21

46 CFR 154.908 - Inert gas generator: Location.  

... 2014-10-01 false Inert gas generator: Location. 154.908 Section 154...Containment Systems § 154.908 Inert gas generator: Location. (a) Except as allowed...paragraph (b) of this section, an inert gas generator must be located in the main...

2014-10-01

22

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 154...Containment Systems § 154.908 Inert gas generator: Location. (a) Except as allowed...paragraph (b) of this section, an inert gas generator must be located in the main...

2011-10-01

23

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

...concentration reading controls the enriching system and activates...alarm and automatic shutdown...majority pair controls the enriching system and activates...alarm and automatic shutdown...concentration reading controls the diluting system and activates...alarm and automatic...

2014-07-01

24

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 COAST...DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment...

2010-10-01

25

46 CFR 153.500 - Inert gas systems.  

Code of Federal Regulations, 2010 CFR

... 5 2010-10-01 2010-10-01 false Inert gas systems. 153.500 Section 153.500 Shipping...DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment...

2010-10-01

26

46 CFR 154.903 - Inert gas systems: General.  

Code of Federal Regulations, 2013 CFR

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

2013-10-01

27

Adsorption of 85 Kr radioactive inert gas into hardening mixtures  

Microsoft Academic Search

Changes in volumetric activity of 85Kr radioactive inert gas take place in the atmosphere: it has increased by around 50% during the past 15 years. The main source\\u000a of such gas is the operation of nuclear power plants and spent nuclear fuel reprocessing plants. 85Kr as an inert gas spreads throughout the entire atmosphere and its ionizing radiation may result in

D. Butkus; J. Kleiza

2011-01-01

28

Inert fluorinated gas MRI: a new pulmonary imaging modality.  

PubMed

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

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

2014-12-01

29

Inert gas analysis of ventilation-perfusion matching during hemodialysis.  

PubMed Central

The mechanism of hypoxemia during hemodialysis was investigated by the multiple inert gas elimination technique in anesthetized, paralyzed, mechanically ventilated dogs. Profound leukopenia occurred in the first hour of a 2-h hemodialysis with a cuprophan membrane and dialysate that contained acetate. Arterial partial pressure of O2 and CO2 and oxygen consumption remained unchanged during dialysis. Pulmonary carbon dioxide elimination and lung respiratory exchange ratio decreased with the initiation of dialysis, remained depressed throughout the duration of dialysis, and returned to predialysis levels after the cessation of dialysis. Cardiac output diminished during dialysis but did not return to base-line levels after dialysis. Multiple indices calculated from inert gas analysis revealed no ventilation-perfusion mismatching during dialysis. The shunt and perfusion to regions of low alveolar ventilation-to-perfusion ratio (VA/Q) were unchanged during dialysis. There was no change in the mean or standard deviation of the profile of the percentage of total perfusion to regions of the lung that had VA/Q near 1.0; nor was there any increase in the directly calculated arterial-alveolar partial pressure differences for the inert gases during dialysis. Dead space became mildly elevated during dialysis. These results show that during dialysis with controlled ventilation there is no ventilation-perfusion mismatching that leads to hypoxemia. During spontaneous ventilation any hypoxemia must occur due to hypoventilation secondary to the CO2 exchange by the dialyzer and subsequent reduction in pulmonary CO2 exchange. PMID:6715542

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

1984-01-01

30

Nuclear Technology. Course 28: Welding Inspection. Module 28-3, Tungsten Inert Gas (TIG), Metal Inert Gas (MIG) and Submerged Arc Welding.  

ERIC Educational Resources Information Center

This third in a series of ten modules for a course titled Welding Inspection presents the apparatus, process techniques, procedures, applications, associated defects, and inspection for the tungsten inert gas, metal inert gas, and submerged arc welding processes. The module follows a typical format that includes the following sections: (1)…

Espy, John

31

Spatial relaxation of electrons in inert and molecular gas plasmas  

SciTech Connect

The electron kinetics in spatially inhomogeneous plasma regions is a subject of growing interest with respect to the microscopic treatment of real discharge plasmas. In order to improve the understanding of the complex electron behaviour in inhomogeneous plasma regions an efficient approach for solving the one-dimensional inhomogeneous electron Boltzmann equation in weakly ionized, collision dominated plasmas has been recently developed. The kinetic equation includes elastic and inelastic collisions of electrons and the action of an inhomogeneous electric field. This method is used to investigate now the relaxation of the electrons to homogeneous states in different inert and molecular gas plasmas under the action of various constant electric fields.

Sigeneger, F.; Winkler, R. [Institut fuer Niedertemperatur-Plasmaphysik, Greifswald (Germany)

1995-12-31

32

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

PubMed

Cytogenetic damage was studied in lymphocytes from 23 welders using the Tungsten Inert Gas (TIG), and 21 welders using the Metal Inert Gas (MIG) and/or Metal Active Gas (MAG) methods on stainless steel (SS). A matched reference group I, and a larger reference group II of 94 subjects studied during the same time period, was established for comparison. Whole blood conventional cultures (CC), cultures in which DNA synthesis and repair were inhibited (IC), and the sister chromatid exchange (SCE) assay were applied in the study. For the CC a statistically significant decrease in chromosome breaks and cells with aberrations was found for both TIG/SS and MIG/MAG/SS welders when compared with reference group II. A non-significant decrease was found for the corresponding parameters for the two groups of welders when compared with their matched referents. A statistically significant negative association was found between measurements of total chromium (Cr) in inhaled air and SCE, and a weaker negative correlation with hexavalent Cr (Cr(VI)) in air. In conclusion, no cytogenetic damage was found in welders exposed to the TIG/SS and MIG/MAG/SS welding fumes with low content of Cr and Ni. On the contrary, a decline in the prevalence of chromosomal aberrations was indicated in the TIG/SS and MIG/MAG/SS welders, possibly related to the suggested enhancement of DNA repair capacity at slightly elevated exposures. PMID:7885396

Jelmert, O; Hansteen, I L; Langård, S

1995-03-01

33

Crystallization of silicon nanoclusters with inert gas temperature control  

NASA Astrophysics Data System (ADS)

We analyze the fundamental process of crystallization of silicon nanoclusters by means of molecular dynamics simulations, complemented by magnetron-sputter inert gas condensation, which was used to synthesize polycrystalline silicon nanoclusters with good size control. We utilize two well-established Si interatomic potentials: the Stillinger-Weber and the Tersoff III. Both the simulations and experiments show that upon cooling down by an Ar gas thermal bath, initially liquid, free-standing Si nanocluster can grow multiple crystal nuclei, which drive their transition into polycrystalline solid nanoclusters. The simulations allow detailed analysis of the mechanism, and show that the crystallization temperature is size-dependent and that the probability of crystalline phase nucleation depends on the highest temperature the cluster reaches during the initial condensation and the cooling rate after it.

Zhao, Junlei; Singh, Vidyadhar; Grammatikopoulos, Panagiotis; Cassidy, Cathal; Aranishi, Kengo; Sowwan, Mukhles; Nordlund, Kai; Djurabekova, Flyura

2015-01-01

34

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...DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment...

2010-10-01

35

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

36

The intelligent control of an inert-gas atomization process  

NASA Astrophysics Data System (ADS)

Intelligent control is an attempt to specify the function of a controller in ways which mimic the decision-making capabilities of humans. Traditionally, issues relating to the emulation of human-like capabilities have fallen in the domain of artificial intelligence. Intelligent processing is a specific form of intelligent control in which the system to be controlled is a process rather than the more conventional mechanical or electrical system. The National Institute of Standards and Technology's program on intelligent processing of metal powders is a multi-disciplinary research initiative investigating the application of intelligent control technologies to improve the state of the art of metal powder manufacturing. This paper reviews the design of the institute's supersonic inert-gas metal-atomizer control system.

Osella, S. A.; Ridder, S. D.; Biancaniello, F. S.; Espina, P. I.

1991-01-01

37

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

SciTech Connect

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

Caskey, B.C.

1982-01-01

38

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

39

Oxygen carrier for gas chromatographic analysis of inert gases in propellants  

NASA Technical Reports Server (NTRS)

Gas chromatographic determination of small quantities of inert gases in reactive propellants is discussed. Operating conditions used for specific analyses of helium in diborane and nitrogen in oxygen difluoride are presented in tabular form.

Cannon, W. A.

1972-01-01

40

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

41

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

Microsoft Academic Search

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

Vasant R. Choudhary; Shafeek A. R. Mulla

1997-01-01

42

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

E-print Network

Evaporation and Condensation of Large Droplets in the Presence of Inert Admixtures Containing the mutual influence of heat and mass transfer during gas absorption and evaporation or condensation transfer during gas absorption by liquid droplets and during droplets evaporation and va- por condensation

Elperin, Tov

43

Test of dilute gas approximation in quantum mechanical model  

Microsoft Academic Search

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

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

1996-01-01

44

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

SciTech Connect

Air-water partitioning for 21 volatile chlorinated or brominated alkanes, alkenes, and aromatics was measured at 20 C by the inert gas stripping method. Results of the measurements are presented in the form of Henry`s law constants (H{sub 12}), air-water partition coefficients (K{sub aw}), and limiting activity coefficients ({gamma}), accurate {gamma} values being obtained only if accurate pure solute vapor pressure data are available. The halocarbons studied in this work are hydrophobic and exhibit enhanced volatilities from their dilute aqueous solutions representing approximately ranges of {gamma} from 230 to 70,000 and H{sub 12} from 2 to 70 MPa. Correct performance of the stripping method for such systems requires special precautions. As confirmed by test measurements on benzene, chlorobenzene, 1,1,1-trichloroethane, and 1,1,2-trichloroethane, the complete equilibration in the stripping cell can be achieved under vigorous mixing of the cell, low stripping gas flow rates (approximately 10 cm{sup 3}/min), and low relative elution rates (0.01 min{sup {minus}1}). Choosing for each system a cell of a suitable volume made it possible to comply with the latter requirement. The results compare well with recent literature values obtained by various methods for some of the halocarbons. For two selected halocarbons (bromobenzene and 1,1-dichloroethane), detailed measurements of the temperature dependence of air-water partitioning were carried out in the range of 10--50 C. These measurements corresponding to the range of H{sub 12} from 5 to 72 MPa provide additional support for the validity of the method.

Hovorka, S.; Dohnal, V. [Inst. of Chemical Technology, Prague (Czech Republic). Dept. of Physical Chemistry] [Inst. of Chemical Technology, Prague (Czech Republic). Dept. of Physical Chemistry

1997-09-01

45

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

DOEpatents

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

1997-01-01

46

Collisional shift of hyperfine line for rubidium in an atmosphere of the buffer inert gas  

NASA Astrophysics Data System (ADS)

New relativistic approach, based on the relativistic many-body perturbation theory using optimized wave functions sets, is applied to calculate the hyper fine structure collision shift for rubidium atom in atmosphere of the helium inert gas. Data for the collisional shifts of the Rb-He system are presented and compared with data available in the literature.

Glushkov, A. V.; Khetselius, O. Yu; Lopatkin, Y. M.; Florko, T. A.; Kovalenko, O. A.; Mansarliysky, V. F.

2014-11-01

47

ENERGETIC INERT GAS ATOM IMPACT EFFECTS DURING ION BEAM MULTILAYER DEPOSITION  

E-print Network

that hyperthermal metal atoms created by sputtering processes such as RF diode (or magnetron) sputtering and ion,6]. This is consistent with other observations that magnetron sputtering gives rise to the best GMR multilayers under. During ion beam sputtering, inert gas neutrals with energies between 50 and 200 eV impact the growth

Wadley, Haydn

48

Inert gas rejection device for zinc-halogen battery systems  

DOEpatents

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

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

1981-01-01

49

Inert gas clusters ejected from bursting bubbles during sputtering.  

PubMed

Ar(+)(n) cluster ions (ngas bubbles. Subsequent ion formation is shown to take place by resonant charge exchange with incident primary Ar+ ions in the gas phase up to at least 175 microm above the surface. Xe+2 clusters are similarly produced from Xe+-bombarded solids. The ion intensities of Ar+2 and Xe+2 are found to have a characteristic second-order dependence on primary Ar+ or Xe+ current density. PMID:12906546

Franzreb, Klaus; Williams, Peter

2003-07-01

50

Influence of inert gas pressure on deposition rate during pulsed laser deposition  

Microsoft Academic Search

.   The deposition rates of permalloy and Ag are monitored during pulsed laser deposition in different inert gas atmospheres.\\u000a Under ultrahigh vacuum conditions, resputtering from the film surface occurs due to the presence of energetic particles in\\u000a the plasma plume. With increasing gas pressure, a reduction of the particle energy is accompanied with a decrease of resputtering\\u000a and a rise

T. Scharf; H. U. Krebs

2002-01-01

51

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

52

Can pyrophoric materials form in oil tankers with inert gas fire protection systems. Final report  

Microsoft Academic Search

A literature study and analysis was made concerning the potential hazard of pyrophoric ignition of flammable vapors in oil tankers with inert gas systems (IGS). Only two pyrophor possibilities seem to be likely: Formation of ferrous sulfide (FeS) and\\/or ferrous oxide (FeO). Both FeS and FeO may be formed in an oxygen limited atmosphere, such as would be the case

Affens

1977-01-01

53

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

54

TIG WELDER LOCATED IN THE CLEAN ROOM OF THE TECHNICAL SERVICES BUILDING TSB - THE INERT GAS WELDING  

NASA Technical Reports Server (NTRS)

TIG WELDER LOCATED IN THE CLEAN ROOM OF THE TECHNICAL SERVICES BUILDING TSB - THE INERT GAS WELDING FACILITY IS USED FOR WELDING REFRACTORY METALS IN CONNECTION WITH THE COLUMBIUM LIQUID SODIUM LOOP PROJECT

1963-01-01

55

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

56

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

SciTech Connect

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

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

2012-04-01

57

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

SciTech Connect

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

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

2012-03-06

58

The Diffusion of Oxygen, Carbon Dioxide, and Inert Gas in Flowing Blood  

PubMed Central

Measurements were made of exchange rates of oxygen, carbon dioxide, and krypton-85 with blood at 37.5°C. Gas transfer took place across a 1 mil silicone rubber membrane. The blood was in a rotating disk boundary layer flow, and the controlling resistance to transfer was the concentration boundary layer. Measured rates were compared with rates predicted from the equation of convective diffusion using velocities derived from the Navier-Stokes equations and diffusivities calculated from the theory for conduction in a heterogeneous medium. The measured absorption rate of krypton-85 was closely predicted by this model. Significant deposition of material onto the membrane surface, resulting in an increased transfer resistance, occurred in one experiment with blood previously used in a nonmembrane type artificial lung. The desorption rate of oxygen from blood at low Po21 was up to four times the corresponding transfer rate of inert gas. This effect is described somewhat conservatively by a local equilibrium form of the convective diffusion equation. The carbon dioxide transfer rate in blood near venous conditions was about twice that of inert gas, a rate significantly greater than predicted by the local equilibrium theory. It should be possible to apply these theoretical methods to predict exchange rates with blood flowing in systems of other geometries. PMID:19211000

Spaeth, E. E.; Friedlander, S. K.

1967-01-01

59

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.

2011-12-01

60

Experimental observations of effects of inert gas on cavity formation during irradiation  

SciTech Connect

Cavity (void) formation and swelling in non-fissile materials during neutron irradiation and charged particle bombardments are reviewed. Helium is the most important inert gas and is primarily active as a cavity nucleant. It also enhances formation of dislocation structure. Preimplantation of helium overstimulates cavity nucleation and gives a different temperature response of swelling than when helium is coimplanted during the damage process. Helium affects, and is affected by, radiation-induced phase instability. Many of these effects are explainable in terms of cavity nucleation on submicroscopic critical size gas bubbles, and on the influence of the neutral sink strength of such bubbles. Titanium and zirconium resist cavity formation when vacancy loops are present.

Farrell, K.

1980-04-01

61

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

Microsoft Academic Search

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

D. Degout; A. Catherinot

1986-01-01

62

Entropy Production and Thermal Conductivity of A Dilute Gas  

E-print Network

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

Yong-Jun Zhang

2011-02-16

63

Spraying of Metallic Powders by Hybrid Gas/Water Torch and the Effects of Inert Gas Shrouding  

NASA Astrophysics Data System (ADS)

A hybrid DC arc plasma torch, combining water and gas stabilization, offers a high flexibility in plasma characteristics. These can be controlled in a wide range by the torch operational parameters, such as arc current and secondary gas flow rate. In this study, their influence on plasma spraying of tungsten and copper was investigated. To suppress the in-flight oxidation of the metals, inert gas shrouding was applied. In-flight particle diagnostics and analysis of free-flight particles and coatings was performed for spraying experiments in the open atmosphere and with argon shrouding. Both in-flight particle behavior and coating properties were found to be sensitive to the torch parameters. The application of shrouding was found to affect particle in-flight parameters, reduce the oxide content in the coatings and generally improve their properties, such as thermal conductivity. However, a different degree of these effects was observed for copper and tungsten.

Kavka, T.; Mat?jí?ek, J.; Ctibor, P.; Hrabovský, M.

2012-06-01

64

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

65

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

66

Characterization of Pb24Te76 quantum dot thin film synthesized by inert gas condensation  

NASA Astrophysics Data System (ADS)

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 5 h at 473 K. 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 473 K). The dc electrical conductivity is increased with raising temperature in the range (303-473 K) 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 473 K for 5 h.

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

2015-01-01

67

Computation of Hypersonic Shock Waves in Inert Gas Mixtures Using the Generalized Boltzmann Equation  

NASA Astrophysics Data System (ADS)

For numerical solution of the Generalized Boltzmann Equation (GBE) for simulating rarefied hypersonic flows in a gas mixture of multiple species, the GBE is formulated in the impulse space. The gas mixtures may consist of both monatomic gases and diatomic gases with arbitrary constituents, concentrations, and mass ratios. The conservative discrete ordinates method of Tcheremissine is applied to validate the solutions against the existing simulations for shock waves in an inert binary mixture of monatomic gases. The method is then exercised for various concentration ratios, mass ratios, and density ratios to evaluate its ability to simulate a wide range of binary gas mixtures. It is also applied to simulate two of the three primary constituents of air (N2, O2, Ar) in a binary mixture at 1:1 concentrations and at the relative concentrations found in air. These solutions can serve as validation test cases for other methods as well as an important building block in developing complex 3D simulations for shock waves in a mixture of multiple gases.

Wilson, Christopher D.; Agarwal, Ramesh K.; Tcheremissine, Felix G.

2011-05-01

68

Noninvasive Determination of Cardiac Output by the Inert-Gas-Rebreathing Method – Comparison with Cardiovascular Magnetic Resonance Imaging  

Microsoft Academic Search

Background: An easy, noninvasive and accurate technique for measuring cardiac output (CO) would be desirable for the diagnosis and therapy of cardiac diseases. Innocor, a novel inert-gas-rebreathing (IGR) system, has shown promising results in smaller studies. An extensive evaluation in a larger, less homogeneous patient collective is lacking. Methods: We prospectively assessed the accuracy and reproducibility of CO measurements obtained

Joachim Saur; Stephan Fluechter; Frederik Trinkmann; Theano Papavassiliu; Stefan Schoenberg; Joerg Weissmann; Dariusch Haghi; Martin Borggrefe; Jens J. Kaden

2009-01-01

69

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

70

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

71

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

72

Unstructured Adaptive Grid Flow Simulations of Inert and Reactive Gas Mixtures  

NASA Astrophysics Data System (ADS)

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

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

2000-05-01

73

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

74

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

PubMed

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

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

2013-01-01

75

Multiproperty empirical isotropic interatomic potentials for CH4–inert gas mixtures  

PubMed Central

An approximate empirical isotropic interatomic potentials for CH4–inert gas mixtures are developed by simultaneously fitting the Exponential-Spline-Morse-Spline-van der Waals (ESMSV) potential form to viscosity, thermal conductivity, thermal diffusion factors, diffusion coefficient, interaction second pressure virial coefficient and scattering cross-section data. Quantum mechanical lineshapes of collision-induced absorption (CIA) at different temperatures for CH4–He and at T = 87 K for CH4–Ar are computed using theoretical values for overlap, octopole and hexadecapole mechanisms and interaction potential as input. Also, the quantum mechanical lineshapes of collision-induced light scattering (CILS) for the mixtures CH4–Ar and CH4–Xe at room temperature are calculated. The spectra of scattering consist essentially of an intense, purely translational component which includes scattering due to free pairs and bound dimers, and the other is due to the induced rotational scattering. These spectra have been interpreted by means of pair-polarizability terms, which arise from a long-range dipole-induced-dipole (DID) with small dispersion corrections and a short-range interaction mechanism involving higher-order dipole–quadrupole A and dipole–octopole E multipole polarizabilities. Good agreement between computed and experimental lineshapes of both absorption and scattering is obtained when the models of potential, interaction-induced dipole and polarizability components are used.

El-Kader, M.S.A.

2012-01-01

76

Fibre Bragg grating sensors for monitoring the metal inert gas and friction stir welding processes  

NASA Astrophysics Data System (ADS)

Fibre Bragg grating (FBG) sensors are finding increased usage in experimental mechanics for monitoring service conditions in structures and other equipment and are currently being tested for process monitoring. In FBG sensors, strain and temperature cause a shift in the Bragg wavelength reflected by the grating contained in these fibres. In situ monitoring of strain and temperature during welding processes increases knowledge of the welded material and the welding process itself. In the present work, two welding processes are monitored using FBG sensors and the complete measurement approach including sensor selection, calibration, instrumentation, welding monitoring and result interpretation is presented. Calibration for strain measurements at constant temperature was performed using a four-point bending test, and temperature calibration was carried out using an oven. Results for a sensor length of 5 mm are presented. Both transient and residual strains were recorded during experiments on metal inert gas and friction stir welding and the possible impact of this monitoring technology is discussed in the light of process optimization and subsequent structural health monitoring.

Richter-Trummer, V.; Silva, S. O.; Peixoto, D. F. C.; Frazão, O.; Moreira, P. M. G. P.; Santos, J. L.; de Castro, P. M. S. T.

2010-08-01

77

Effect of inert cover gas on performance of radioisotope Stirling space power system  

NASA Astrophysics Data System (ADS)

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 on missions 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, R.; Kumar, V.; Or, C.; Schock, A.

2001-02-01

78

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

79

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

PubMed

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

McElearney, N; Irvine, D

1993-07-01

80

Recent study of nanomaterials prepared by inert gas condensation using ultra high vacuum chamber  

NASA Astrophysics Data System (ADS)

The ultra high vacuum chamber was developed in the Department of Nuclear Physics, University of Madras with the funding from DST, India. This UHV chamber is used to prepare nanocrystalline materials by inert gas condensation technique (IGCT). Nanocrystalline materials such as PbF_{2}, Mn^{2+}-doped PbF_{2}, Sn-doped In_{2}O_{3} (ITO), ZnO, Al_{2}O_{3}, Ag_{2}O, CdO, CuO, ZnSe:ZnO etc., were prepared by this technique and characterized. Results of some of these materials will be presented in this paper. In solid-state ^{207}Pb NMR on PbF_{2} a separate signal due to the presence of grain boundary has been observed. The structural phase transition pressure during the phase transformation from the cubic phase to orthorhombic phase under high pressure shows an increase with the decrease in grain size. Presence of electronic centres in nanocrystalline PbF_{2} is observed from Raman studies and the same has been confirmed by photoluminescence studies. Al_{2}O_{3} was prepared and ^{56}Fe ions were implanted. After implantation segregation of ^{56}Fe ions was examined by SEM. The oxidation properties of ITO were studied by HRTEM. As against the expectation of oxide coating on individual nanograins of In-Sn alloy, ITO nanograins grew into faceted nanograins on heat treatment in air and O_{2} atmosphere. The growth of ITO under O_{2} atmosphere showed pentagon symmetry. The PMN was initially prepared by solid-state reaction. Further, this PMN relaxor material will be used to convert into nanocrystalline PMN by IGCT with sputtering and will be studied.

Ramasamy, S.; Smith, D. J.; Thangadurai, P.; Ravichandran, K.; Prakash, T.; Padmaprasad, K.; Sabarinathan, V.

2005-11-01

81

Effect of inert species in gas phase on oscillatory dynamics of oxidation system of CO on Pt(100)  

NASA Astrophysics Data System (ADS)

We present a Monte Carlo simulation for the global oscillation of the CO catalytic oxidation system in the presence of inert species in gas phase, which can adsorb and desorb on the catalytic surface but cannot react with other species. It is found that the impurity has a dramatic effect on the oscillatory dynamics, although it does not involve in the reaction of CO oxidation. The simulation results show that with an increase in the fraction of impurity in gas phase, the periodic oscillation may change into an irregular oscillation and even can be inhibited completely. However, as the desorption rate of the impurity is increased, the regular oscillation will be recovered again.

Hua, Da-Yin; Zhang, Feng; Ma, Yu-Qiang

2003-05-01

82

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

83

Noninvasive cardiac output measurement by inert gas rebreathing in suspected pulmonary hypertension.  

PubMed

The objective of this study was to evaluate inert gas rebreathing (IGR) reliability in cardiac output (CO) measurement compared with Fick method and thermodilution. IGR is a noninvasive method for CO measurement; CO by IGR is calculated as pulmonary blood flow plus intrapulmonary shunt. IGR may be ideal for follow-up of patients with pulmonary hypertension (PH), sparing the need of repeated invasive right-sided cardiac catheterization. Right-sided cardiac catheterization with CO measurement by thermodilution, Fick method, and IGR was performed in 125 patients with possible PH by echocardiography. Patients were grouped according to right-sided cardiac catheterization-measured mean pulmonary and wedge pressures: normal pulmonary arterial pressure (n = 20, mean pulmonary arterial pressure = 18 ± 3 mm Hg, pulmonary capillary wedge pressure = 11 ± 5 mm Hg), PH and normal pulmonary capillary wedge pressure (PH-NW, n = 37 mean pulmonary arterial pressure = 42 ± 13 mm Hg, pulmonary capillary wedge pressure = 11 ± 6 mm Hg), and PH and high pulmonary capillary wedge pressure (PH-HW, n = 68, mean pulmonary arterial pressure = 37 ± 9 mm Hg, pulmonary capillary wedge pressure = 24 ± 6 mm Hg). Thermodilution and Fick measurements were comparable. Fick and IGR agreement was observed in normal pulmonary arterial pressure (CO = 4.10 ± 1.14 and 4.08 ± 0.97 L/min, respectively), whereas IGR overestimated Fick in patients with PH-NW and those with PH-HW because of intrapulmonary shunting overestimation in hypoxemic patients. When patients with arterial oxygen saturation (SO2) ?90% were excluded, IGR and Fick agreement improved in PH-NW (CO = 4.90 ± 1.70 and 4.76 ± 1.35 L/min, respectively) and PH-HW (CO = 4.05 ± 1.04 and 4.10 ± 1.17 L/min, respectively). In hypoxemic patients, we estimated pulmonary shunt as Fick - pulmonary blood flow and calculated shunt as: -0.2423 × arterial SO2 + 21.373 L/min. In conclusion, IGR is reliable for CO measurement in patients with PH with arterial SO2 >90%. For patients with arterial SO2 ?90%, a new formula for shunt calculation is proposed. PMID:24315114

Farina, Stefania; Teruzzi, Giovanni; Cattadori, Gaia; Ferrari, Cristina; De Martini, Stefano; Bussotti, Maurizio; Calligaris, Giuseppe; Bartorelli, Antonio; Agostoni, Piergiuseppe

2014-02-01

84

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

85

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

DOEpatents

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

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

1997-01-01

86

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

DOEpatents

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

Bitensky, M.W.; Yoshida, Tatsuro

1997-04-29

87

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

88

Computation of decompression schedules for single inert gas-oxygen dives using a hand-held programmable calculator.  

PubMed

An algorithm for on-site computation with a hand-held programmable calculator (TI-59, Texas Instruments) of single inert-gas decompression schedules is described. This program is based on Workman's 'M-value' method. It can compute decompression schedules with changes in the oxygen content of the breathing mixture and extension of stay at any decompression stop. The features of the program that enable calculation of atypical dive profiles, along with the portability of small calculators, would make such an algorithm suitable for on-site applications. However, since dive profiles generated by the program have not yet been tested, divers are warned not to generate schedules until their safety has been established by field tests. PMID:6257447

Ranade, A; Peterson, R E

1980-08-01

89

Decomposition of dilute trichloroethylene by nonthermal plasma processing-gas flow rate, catalyst, and ozone effect  

Microsoft Academic Search

Decomposition performance of dilute (100-1000 ppm) trichloroethylene (TCE) contaminated in air by using nonthermal plasma processing was studied to improve the decomposition efficiency. Three kinds of experiments were performed. One is the observation of the decomposition efficiency related to the processing gas flow rate. There exists an optimal gas flow rate for our reactor. The second experiment is the plasma

Tetsuji Oda; Kei Yamaji; Tadashi Takahashi

2004-01-01

90

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

91

Effects of inert species in the gas phase in a model for the catalytic oxidation of CO  

NASA Astrophysics Data System (ADS)

We study by kinetic Monte Carlo simulations the catalytic oxidation of carbon monoxide on a surface in the presence of contaminants in the gas phase. The process is simulated by a Ziff-Gulari-Barshad (ZGB) model that has been modified to include the effect of the contaminants and to eliminate an unphysical oxygen poisoned phase at very low CO partial pressures. The impurities can adsorb and desorb on the surface but otherwise remain inert. We find that if the impurities cannot desorb, no matter how small their proportion in the gas mixture, the reactive window and discontinuous transition to a CO poisoned phase at high CO pressures that characterize the original ZGB model disappear. The coverages become continuous, and once the surface has reached a steady state there is no production of CO2. This is quite different from the behavior of systems in which the surface presents a fixed percentage of impurities. When the contaminants are allowed to desorb, the reactive phase appears again for CO pressures below a value that depends on the proportion of contaminants in the gas and on their desorption rate.

Buendía, G. M.; Rikvold, P. A.

2012-03-01

92

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

93

Modeling and analyzing the effects of heat treatment on the characteristics of magnesium alloy joint welded by the tungsten-arc inert gas welding  

Microsoft Academic Search

The objective of this paper is to present the mathematical models for modeling and analysis of the effects of heat treatment on the characteristics of magnesium alloy joint welded by the tungsten-arc inert gas (TIG) welding. The process of heat treatment adopts the tempering process with varying processing parameters, including tempering temperature and tempering time. The microstructure and mechanical properties

Te-Chang Tsai; Chih-Chung Chou; Deng-Maw Tsai; Ko-Ta Chiang

2011-01-01

94

The effect of dilution on the gas retention behavior of Tank 241-SY- 103 waste  

SciTech Connect

Twenty-five of the 177 underground waste storage tanks on the Hanford Site have been placed on the Flammable Gas watch list. These 25 tanks, containing high-level waste generated during plutonium and uranium processing, have been identified as potentially capable of accumulating flammable gases above the lower flammability limit (Babad et al. 1991). In the case of Tanks 241-SY-101 and 241-SY-103, it has been proposed that diluting the tank waste may mitigate this hazard (Hudson et al. 1995; Stewart et al. 1994). The effect of dilution on the ability of waste from Tank 241-SY-103 to accumulate gas was studied at Pacific Northwest National Laboratory. A similar study has been completed for waste from Tank 241-SY-101 (Bredt et al. 1995). Because of the additional waste-storage volume available in Tank 241-SY-103 and because the waste is assumed to be similar to that currently in Tank 241-SY-101, Tank 241-SY-103 became the target for a demonstration of passive mitigation through in-tank dilution. In 1994, plans for the in-tank dilution demonstration were deferred pending a decision on whether to pursue dilution as a mitigation strategy. However, because Tank 241-SY-103 is an early retrieval target, determination of how waste properties vary with dilution will still be required.

Bredt, P.R.; Tingey, S.M.

1996-01-01

95

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

96

GAS HOLDUP IN BAFFLED BUBBLE COLUMNS OF DILUTE SLURRIES OF FINE POWDERS AND VISCOUS LIQUIDS  

Microsoft Academic Search

Experimental gas phase holdup data reported by the authors as taken on two baffled bubble columns and involving slurries of fine powders (average particle diameter ?90 ?m) and dilute suspensions (mass fraction ? 20 percent) in viscous fluids are re-examined after correction for a small calculation error in superficial gas velocity. The two bubble columns are: a Plexiglas bubble column, 0.108 m in

S. C. SAXENA; N. S. RAO; Z. D. CHEN

1992-01-01

97

Precipitate microstructures and resulting properties of Al-Zn-Mg metal inert gas-weld heat-affected zones  

NASA Astrophysics Data System (ADS)

Using the combination of small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM), the precipitate microstructure is quantitatively investigated in the heat-affected zones (HAZs) of Al-Zn-Mg metal inert gas (MIG)-welds, and the resulting mechanical properties are determined by hardness measurements. Three initial states prior to welding (T4, T6, and T7) are investigated, and the subsequent microstructure evolution during natural aging and postwelding heat treatments (PWHTs) is assessed. The critical part of the HAZ is shown to be the transition region where partial dissolution of the initially present precipitates occurs. In this transition zone, precipitate coarsening is shown to occur for the T6 and T7 initial states, contrarily to the T4 material. After PWHT, the T6 and T7 materials experience a weak region related to this coarsening behavior, whereas the T4 material HAZ is able to recover a homogeneous microstructure after a suitably chosen PWHT. Simple model ramp heat treatments are shown to describe the main phenomena involved in the HAZ. Finally, a precipitation hardening model is successfully applied to the microstructural data to describe the hardness profiles in the various HAZs.

Nicolas, M.; Deschamps, A.

2004-05-01

98

Influence of TIG welding thermal cycles on HSLA-100 steel plate. Technical report. [TIG (tungsten-inert gas)  

SciTech Connect

A series of five bead on plate autogenous tungsten-inert-gas (TIG) welds were performed on U.S. Navy HSLA-100 steel. Power variations in these welds was achieved by altering the welding speed, voltage and current and were as follows (in kJ/mm); 0.7, 1.1, 1.2, 1.6 and 2.2. No evidence was found of either weld metal or underbead HAZ cracking in any of the welds illustrating the advantage of low carbon steel for both weld wire and base plate. Microhardness traverses across both the weld metals and HAZs gave a maximum. Vickers diamond pyramid hardness of 345 HV in the coarse grain HAZ next to the fusion line in the lowest power weld; for the highest power weld this was somewhat lower at 328 HV. These are well below 375 which is usually considered to be the lowest Vickers Hardness value for which severe hydrogen induced cold cracking is observed in this type of steel. Optical, scanning and transmission electron microscopy studies of the coarse grain HAZ microstructure in the regions of maximum hardness was correlated with the continuous cooling transformation diagram for this steel and good agreement between observed and predicted microstructures was obtained.

Fox, A.G.; Bhole, S.D.

1993-11-01

99

Heat transfer coefficients of dilute flowing gas-solids suspensions  

NASA Technical Reports Server (NTRS)

Heat transfer coefficients of air-glass, argon-glass, and argon-aluminum suspensions were measured in horizontal and vertical tubes. The glass, 21.6 and 36.0 micron diameter particles, was suspended at gas Reynolds numbers between 11,000 and 21,000 and loading ratios between 0 and 2.5. The presence of particles generally reduced the heat transfer coefficient. The circulation of aluminum powder in the 0.870 inch diameter closed loop system produced tenacious deposits on protuberances into the stream. In the vertical test section, the Nusselt number reduction was attributed to viscous sublayer thickening; in the horizontal test section to particle deposition.

Kane, R. S.; Pfeffer, R.

1973-01-01

100

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.

101

Stability Characteristics of Turbulent Hydrogen Dilute Diffusion Flames  

Microsoft Academic Search

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

Nathan T. Weiland; Peter A. Strakey

2009-01-01

102

46 CFR 154.1848 - Inerting.  

...the flammable vapors are purged from the tank by inert gas before air is admitted; and (4) When gas free cargo tanks are to be filled with a flammable cargo, air is purged from the tank by inert gas until the oxygen...

2014-10-01

103

Temperature profile of a dilute gas undergoing a plane Poiseuille flow  

NASA Astrophysics Data System (ADS)

The temperature and the pressure profile of a dilute or moderately rarefied gas undergoing a plane Poiseuille flow are calculated and compared with simulation data for a gas of hard spheres as first presented by Malek Mansour, Baras and Garcia (Physica A 240 (1997) 225). The Boltzmann equation is solved by the moment method. The desired solution including terms up to second order in the applied force driving the flow, requires the use of a 19 moments approximation. It comprises results based on somewhat simpler 13 moments approximation which are qualitatively reasonable for the present problem.

Hess, Siegfried; Mansour, M. Malek

1999-10-01

104

Inert hydrocarbon-based refrigerants  

Microsoft Academic Search

This paper determines the flammability properties of two hydrocarbon blends, natural gas and propane–butane refrigerant, mixed with CF3I and C3F7H inerting agents. Four flammability envelopes are obtained allowing the determination of the minimum inerting concentrations and the maximum hydrocarbon to suppressant weight ratios for formulating non-flammable hydrocarbon refrigerants. These ratios are calculated from the slopes of lines drawn from the

B. Z. Dlugogorski; R. K. Hichens; E. M. Kennedy

2002-01-01

105

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

106

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

107

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

108

Thermal conductivity for a bidimensional dilute gas within the Chapman-Enskog approximation  

E-print Network

In this work we explicitly calculate the thermal conductivity for a bidimensional dilute gas of neutral molecules by solving Boltzmann's equation. Chapman-Enskog's method is used in order to analytically obtain the transport coefficient to first approximation. The result is expressed in terms of a collision integral for a unspecified molecular interaction model. The particular case of a hard disks model is addressed yielding a T 1/2 dependence with the temperature which is consistent with the one obtained by J. V. Sengers [1] and widely used in the literature as the low density limit in the Enskog expansion. The corresponding value for bidimensional Maxwellian molecules is also obtained.

Mendez, A R; Escobar, Eric

2015-01-01

109

Medium effects and the shear viscosity of the dilute Fermi gas away from the conformal limit  

NASA Astrophysics Data System (ADS)

We study the shear viscosity of a dilute Fermi gas as a function of the scattering length in the vicinity of the unitarity limit. The calculation is based on kinetic theory, which provides a systematic approach to transport properties in the limit in which the fugacity z =n ?3/2 is small. Here, n is the density of the gas and ? is the thermal wavelength of the fermions. At leading order in the fugacity expansion, the shear viscosity is independent of density, and the minimum shear viscosity is achieved at unitarity. At the next order, medium effects modify the scattering amplitude as well as the quasiparticle energy and velocity. We show that these effects shift the minimum of the shear viscosity to the Bose-Einstein condensation side of the resonance, in agreement with the result of recent experiments.

Bluhm, M.; Schäfer, T.

2014-12-01

110

Correlation of leak rates of various fluids with the leak rate of an inert gas in the same configuration  

NASA Technical Reports Server (NTRS)

NASA is interested in field testing for possible leakage in their fueling systems; however, many fuels are hazardous to the extent that personnel cannot be on hand when the system is being monitored. It is proposed that an inert material such as helium be used on the field test, and that those results be calibrated to simulate the actual process. A technique such as this would allow personnel to be on site during the testing and use techniques to determine the behavior of the system that could not be used otherwise. This endeavor attempts to develop such a correlation. The results show promise, but more refinement and data are needed.

Schleier, Howard

1990-01-01

111

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

112

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

NASA Astrophysics Data System (ADS)

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

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

113

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

NASA Astrophysics Data System (ADS)

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, porosity, redox, etc.) on gross fluxes based on bulk concentration measurements alone. One novel approach for quantifying gross fluxes of N2O and N2 is 'stable isotope pool dilution;' a technique that has been successfully applied to study bidirectional fluxes of other biogenic compounds, such as CH4 and halocarbons. To evaluate the efficacy of this method for quantifying gross N2O and N2 fluxes, we conducted a combined field and laboratory test of the pool dilution technique along side conventional measures of nitrification and denitrification. Experiments were conducted in a N-rich managed peatland pasture in the Sacramento-San Joaquin Delta, California, USA. Field and laboratory measurements were performed in a broad range of microforms and microtopes spanning a range of hydrologic and environmental conditions. Field experiments focussed on gross fluxes of N2O and N2 in upper soil horizons; the soil layers that exchange most rapidly with the atmosphere. Laboratory experiments indicated that 15N pool dilution compares favourably with more conventional measures of N2O and N2 flux, such as acetylene inhibition or the 15NO3- pulse-trace approach. Gross N2O fluxes greatly exceeded N2 fluxes by as much as an order of magnitude or more, and averaged 6.1 ± 2.2 mg N m-2 d-1, with a range from 0.06 to 63.13 mg N m-2 d-1. N2O:N2 emissions ratios generally exceeded 1 except along slopes, with an overall range of 0.2 to 30.9. NH4+ concentrations and denitrifying enzyme activity were the best predictors of gross N2O fluxes in the field (r2 = 0.65). Net N2O production rates explained 53 percent of the variability in gross N2 fluxes, whereas N2O:N2 ratios were best predicted by the combination of water-filled pore space and mineral N concentration (r2 = 0.44). This research highlights the potential of the pool dilution approach for quantifying gross fluxes of N2O and N2 from surface soils under both field and laboratory conditions. Future experiments will couple these measures of soil surface fluxes with push-pull methods for determining gross N2O and N2 fluxes at depth, and natural abundance isotopomer measurements to determine sources of N2O.

Arn Teh, Yit; Yang, Wendy; Silver, Whendee L.

2010-05-01

114

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

115

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

116

[Determination of endogenous agmatine in rat plasma by isotope dilution-gas chromatography-mass spectrometry].  

PubMed

A method for the determination of endogenous agmatine in rat plasma was developed by isotope dilution-gas chromatography-negative chemical ionization mass spectrometry (GC-NCI/MS). The plasma samples were analyzed after protein precipitation, evaporation, derivatization by hexafluoroacetone (HFAA), and clean-up on a Florisil SPE column. The GC-MS analysis utilized stable isotope d8-agmatine as internal standard. The samples after treatme were tested by negative chemical ionization with selected ion monitoring (SIM) which was set at m/z 492 (molecular ion of agmatine) and m/z 500 (molecular ion of internal standard). The limit of detection (LOD) of agmatine standard solution was 0.005 7 ng/mL. The calibration curve of the agmatine spiked in rat plasma showed a good linear relationship at the range of 1.14-57.0 ng/mL (r = 0.997). The recoveries of agmatine spiked in rat plasma ranged from 92.3% to 109.8%. Inter-day and intra-day precisions were less than 15%. The average concentration level of agmatine in rat plasma was (22 +/- 9) ng/mL, and there was no significant difference between male and female SD rats (p > 0.05). The method is high sensitive and specific, and can be used for the determination of endogenous agmatine in plasma. It provides a strong support for the subsequent research of agmatine. PMID:25255573

Qiu, Zhongli; Lin, Ying; Xiong, Zhili; Xie, Jianwei

2014-07-01

117

Laws of the DC arc in an inert gas during melting in furnaces with a tungsten electrode  

NASA Astrophysics Data System (ADS)

The I-V and voltage-baric characteristics of the dc arc glowing in argon between a tungsten cathode and a molten anode made of titanium, chromium, or manganese are studied at various gas pressures, arc currents, and arc lengths. The arc is probed to establish the relation between the voltage drop across the arc and its regions on the anode material and the melting conditions.

Belyanchikov, L. N.

2012-06-01

118

Direct quantitative determination of cyanamide by stable isotope dilution gas chromatography-mass spectrometry.  

PubMed

Cyanamide is a multifunctional agrochemical used, for example, as a pesticide, herbicide, and fertilizer. Recent research has revealed that cyanamide is a natural product biosynthesized in a leguminous plant, hairy vetch (Vicia villosa). In the present study, gas chromatography-mass spectrometry (GC-MS) equipped with a capillary column for amines was used for direct quantitative determination of cyanamide. Quantitative signals for ((14)N(2))cyanamide, ((15)N(2))cyanamide (internal standard for stable isotope dilution method), and m-(trifluoromethyl)benzonitrile (internal standard for correcting errors in GC-MS analysis) were recorded as peak areas on mass chromatograms at m/z 42 (A(42)), 44 (A(44)), and 171 (A(IS)), respectively. Total cyanamide content, ((14)N(2))cyanamide plus ((15)N(2))cyanamide, was determined as a function of (A(42)+A(44))/A(IS). Contents of ((14)N(2))cyanamide and ((15)N(2))cyanamide were then calculated by multiplying the total cyanamide content by A(42)/(A(42)+A(44)) and A(44)/(A(42)+A(44)), respectively. The limit of detection for the total cyanamide content by the GC-MS analysis was around 1ng. The molar ratio of ((14)N(2))cyanamide to ((15)N(2))cyanamide in the injected sample was equal to the observed A(42)/A(44) value in the range from 0.1 to 5. It was, therefore, possible to use the stable isotope dilution method to quantify the natural cyanamide content in samples; i.e., the natural cyanamide content was derived by subtracting the A(42)/A(44) ratio of the internal standard from the A(42)/A(44) ratio of sample spiked with internal standard, and then multiplying the resulting difference by the amount of added ((15)N(2))cyanamide (SID-GC-MS method). This method successfully gave a reasonable value for the natural cyanamide content in hairy vetch, concurring with the value obtained by a conventional method in which cyanamide was derivatized to a photometrically active compound 4-cyanimido-1,2-naphthoquinone and analyzed with reversed-phase HPLC (CNQ-HPLC method). The determination range of cyanamide in the SID-GC-MS method was almost the same as that in the CNQ-HPLC method; however, the SID-GC-MS method was much simpler than the CNQ-HPLC method. PMID:16314170

Hiradate, Syuntaro; Kamo, Tsunashi; Nakajima, Eri; Kato, Kenji; Fujii, Yoshiharu

2005-12-01

119

Derivation of the effective action of a dilute Fermi gas in the unitary limit of the BCS-BEC crossover  

SciTech Connect

The effective action describing the gapless Nambu-Goldstone, or Anderson-Bogoliubov, mode of a zero-temperature dilute Fermi gas at unitarity is derived up to next-to-leading order in derivatives from the microscopic theory. Apart from a next-to-leading order term that is suppressed in the BCS limit, the effective action obtained in the strong-coupling unitary limit is proportional to that obtained in the weak-coupling BCS limit.

Schakel, Adriaan M.J., E-mail: schakel@df.ufpe.br [Institut fuer Theoretische Physik, Universitaet Leipzig, Postfach 100 920, D-04009 Leipzig (Germany); Laboratorio de Fisica Teorica e Computacional, Departamento de Fisica, Universidade Federal de Pernambuco, 50670-901 Recife-PE (Brazil)

2011-01-15

120

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

SciTech Connect

In this paper, the effects of heat input on the microstructures and mechanical properties of tungsten inert gas arc butt-welded AZ61 magnesium alloy plates were investigated by microstructural observations, microhardness tests and tensile tests. The results show that with an increase of the heat input, the grains both in the fusion zone and the heat-affected zone coarsen and the width of the heat-affected zone increased. Moreover, an increase of the heat input resulted in a decrease of the continuous {beta}-Mg{sub 17}Al{sub 12} phase and an increase of the granular {beta}-Mg{sub 17}Al{sub 12} phase in both the fusion zone and the heat-affected zone. The ultimate tensile strength of the welded joint increased with an increase of the heat input, while, too high a heat input resulted in a decrease of the ultimate tensile strength of the welded joint. In addition, the average microhardness of the heat-affected zone and fusion zone decreased sharply with an increase of the heat input and then decreased slowly at a relatively high heat input.

Min Dong [College of Material Science and Engineering, Chongqing University, Chongqing 400044 (China); Shen Jun, E-mail: shenjun2626@163.com [College of Material Science and Engineering, Chongqing University, Chongqing 400044 (China); Lai Shiqiang; Chen Jie [College of Material Science and Engineering, Chongqing University, Chongqing 400044 (China)

2009-12-15

121

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

NASA Astrophysics Data System (ADS)

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

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

2012-11-01

122

Column Calibration Factor to Study the Composition Dependence of the Thermal Diffusion Factors of Inert Gas Mixtures  

NASA Astrophysics Data System (ADS)

The experimental thermal diffusion factors ?T of He4-Ar40 and Ne20-Xe132 gas mixtures at different compositions of the lighter components and an isotopic natural mixture of Ne20-Ne22 are estimated at the mean temperature \\bar{T}{=}340 K by the column calibration factor method from the available values of ln qe(qe being the equilibrium separation factor) for those mixtures at different pressures in atmosphere for each composition, measured by J. M. Saviron et al. in a thermal diffusion column with the column calibration factor Fs{=}3.946, the value (at \\bar{T}{=}340 K) derived from the formula Fs{=}68.94796-0.3174514 \\bar{T}+3.71383× 10-4T2 as obtained by S. Acharyya et al. It is shown that the experimental ?T’s, thus estimated with the help of Fs and ln qmax, agree excellently with those due to the existing methods using molecular models as well as with those due to Slieher’s model-independent method, so far as their magnitudes and the trends of their variation with the mole fraction of the lighter components are concerned. This suggests that the present method is a unique one which can safely be used to study the composition dependence of ?T in both the isotopic and nonisotopic cases.

Datta, A. K.; Dasgupta, G.; Acharyya, S.

1990-10-01

123

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

SciTech Connect

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

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

1997-09-01

124

Modeling of gob inertization with nitrogen  

SciTech Connect

The paper deals with a modeling of nitrogen distribution throughout gob so that the effect of inertization could be measured. The model takes into account flow transient character, methane liberation and different locations for nitrogen injection. Computer modeling, reflecting mathematical models is done by a specially created computer program NITRO{_}GOB, which allows dealing with different parameters of air leakage, of coal waste distribution as well as of gas picture in the gob before inertization. Effective evaluation of the most important parameters--injection place and nitrogen volume--on gob gas picture is illustrated under typical cross-section profiles of gas concentrations in gob depth and also under oxygen reduction in hazardous zones throughout gob surface. Thus the two aerodynamically linked parameters for object inertization control--place of injection and nitrogen amounts, can be studied. As a result of modeling, some changes in injection technology are suggested, leading to improvement of nitrogen distribution in SPONCOM hazard zones.

Michaylov, M.; Vlasseva, E.

1999-07-01

125

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

126

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

127

Measurement of Pyrethroid, Organophosphorus, and Carbamate Insecticides in Human Plasma using Isotope Dilution Gas Chromatography-High Resolution Mass Spectrometry  

PubMed Central

We have developed a gas chromatography-high resolution mass spectrometry method for measuring pyrethroid, organophosphorus, carbamate and fipronil pesticides and the synergist piperonyl butoxide in human plasma. Plasma samples were extracted using solid phase extraction and were then concentrated for injection and analysis using isotope dilution gas chromatography-high resolution mass spectrometry. The limits of detection ranged from 10 to 158 pg/mL with relative recoveries at concentrations near the LODs (e.g., 25 or 250 pg/mL) ranging from 87% to 156% (9 of the 16 compounds were withing ± 15% of 100%). The extraction recoveries ranged from 20% to 98% and the overall method relative standard deviations were typically less than 20% with some exceptions. Analytical characteristics were determined at 25, 250, and 1000 pg/mL. PMID:20434413

Pérez, José J.; Williams, Megan K.; Weerasekera, Gayanga; Smith, Kimberly; Whyatt, Robin M.; Needham, Larry L.; Barr, Dana Boyd

2010-01-01

128

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

129

Analysis of methoxypyrazines in wine using headspace solid phase microextraction with isotope dilution and comprehensive two-dimensional gas chromatography.  

PubMed

This study reports an optimized headspace-solid phase microextraction (HS-SPME) method for the determination of methoxypyrazines in wine. Analysis was performed by using comprehensive two-dimensional gas chromatography with novel detection capabilities, including nitrogen phosphorus detection (GC x GC-NPD) and time-of-flight mass spectrometry (GC x GC-TOFMS). In the latter, stable isotope dilution was performed for the quantitation of 2-methoxy-3-(2-methylpropyl) pyrazine (IBMP), using labelled 2-(2H3)methoxy-3-(2-methylpropyl)pyrazine (d3-IBMP) as the internal standard, and resolution of the two analogues was facilitated using the deconvolution capabilities of the TOFMS. This research represents the first report of HS-SPME with isotope dilution and GC x GC-TOFMS (GC x GC-IDTOFMS). Analysis by GC x GC-NPD enabled detection limits of 0.5 ng/L for the quantitation of IBMP, which was superior to that obtained using GC x GC-IDTOFMS (1.95 ng/L). Nevertheless, both methods were adequately sensitive for real wine analysis, yielding highly comparable IBMP concentrations of 26.1 and 27.8 ng/L, respectively, from a Sauvignon blanc wine. The complexity of the real wine headspace was simplified as a result of selective detection using GC x GC-NPD and, in the case of GC x GC-IDTOFMS, the use of extracted ion chromatograms (EICs). PMID:16013834

Ryan, Danielle; Watkins, Peter; Smith, Jason; Allen, Malcolm; Marriott, Philip

2005-06-01

130

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

131

Evaluation of boundary conditions used to model dilute, turbulent gas\\/solids flows in a pipe  

Microsoft Academic Search

A turbulent gas\\/solids model, based on the work of Simonin [1] [Simonin, O., 1996. Continuum modeling of dispersed two-phase flows, in Combustion and Turbulence in Two-Phase Flows, Von Karman Institute of Fluid Dynamics Lecture Series 1996-2], has been recently implemented in the MFIX computational fluid dynamic (CFD) code. This theory includes the effects of turbulence in the gas phase as

Sofiane Benyahia; Madhava Syamlal; Thomas J. O'Brien

2005-01-01

132

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

SciTech Connect

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

Huang, L.Q.

1989-03-01

133

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

NASA Astrophysics Data System (ADS)

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

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

1997-03-01

134

Attempted density blowup in a freely cooling dilute granular gas: hydrodynamics versus molecular dynamics.  

PubMed

It has been recently shown [I. Fouxon, Phys. Rev. E 75, 050301(R) (2007); I. Fouxon, Phys. Fluids 19, 093303 (2007)] that, in the framework of ideal granular hydrodynamics (IGHD), an initially smooth hydrodynamic flow of a granular gas can produce an infinite gas density in a finite time. Exact solutions that exhibit this property have been derived. Close to the singularity, the granular gas pressure is finite and almost constant. We report molecular dynamics (MD) simulations of a freely cooling gas of nearly elastically colliding hard disks, aimed at identifying the "attempted" density blowup regime. The initial conditions of the simulated flow mimic those of one particular solution of the IGHD equations that exhibits the density blowup. We measure the hydrodynamic fields in the MD simulations and compare them with predictions from the ideal theory. We find a remarkable quantitative agreement between the two over an extended time interval, proving the existence of the attempted blowup regime. As the attempted singularity is approached, the hydrodynamic fields, as observed in the MD simulations, deviate from the predictions of the ideal solution. To investigate the mechanism of breakdown of the ideal theory near the singularity, we extend the hydrodynamic theory by accounting separately for the gradient-dependent transport and for finite density corrections. PMID:18352020

Puglisi, Andrea; Assaf, Michael; Fouxon, Itzhak; Meerson, Baruch

2008-02-01

135

Ground-state energy and depletions for a dilute binary Bose gas  

SciTech Connect

When calculating the ground-state energy of a weakly interacting Bose gas with the help of the customary contact pseudopotential, one meets an artificial ultraviolet divergence which is caused by the incorrect treatment of the true interparticle interactions at small distances. We argue that this problem can be avoided by retaining the actual, momentum-dependent interaction matrix elements, and use this insight for computing both the ground-state energy and the depletions of a binary Bose gas mixture. Even when considering the experimentally relevant case of equal masses of both species, the resulting expressions are quite involved, and they are no straightforward generalizations of the known single-species formulas. On the other hand, we demonstrate in detail how these latter formulas are recovered from our two-species results in the limit of vanishing interspecies interaction.

Eckardt, Andre; Weiss, Christoph; Holthaus, Martin [Institut fuer Physik, Carl von Ossietzky Universitaet, D-26111 Oldenburg (Germany)

2004-10-01

136

Assay of blood and tissue oxaloacetate and alpha-ketoglutarate by isotope dilution gas chromatography-mass spectrometry.  

PubMed

The assay of oxaloacetate and alpha-ketoglutarate in biological samples is complicated by their chemical instability and low concentrations. We present a quantitative assay for physiological concentrations of these metabolites by isotope dilution gas chromatography-mass spectrometry. Samples are spiked with the corresponding internal standards of [U-13C4]oxaloacetate and [U-13C5] alpha-ketoglutarate prior to their treatment with hydroxylamine. After ethyl acetate extraction and evaporation of the organic phases, the oximes are converted to t-butyldimethylsilyl ethers and analyzed by selected ion monitoring gas chromatography-mass spectrometry of the [M-57]+ ion in electron impact. Although the internal standards of [U-13C4]oxaloacetate and [U-13C5] alpha-ketoglutarate are not commercially available, they can easily be synthesized in 30 min by reacting [1,2,3,6-13C4]citrate with citrate lyase, and L-[U-13C5]glutamate with pyruvate and glutamate-pyruvate transaminase, respectively. Because of their chemical instability, the internal standards are prepared on the day of the analysis. A stock solution of [1,2,3,6-13C4]citrate is prepared from L-[U-13C4]aspartate using citrate synthase and glutamate-oxaloacetate transaminase and then purified and kept frozen until required. The detection limit of the method is 0.05 nmol in a given sample. The method was applied to measurements of oxaloacetate and alpha-ketoglutarate in human blood and rat liver. PMID:7733461

Laplante, A; Comte, B; Des Rosiers, C

1995-01-20

137

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

138

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

139

Design, fabrication, and testing of a full-scale breadboard nitrogen generator for fuel tank inerting application. Final report  

Microsoft Academic Search

Aircraft fuel tank ullage may contain a mixture of fuel vapor in air that presents a fire and explosion hazard. This hazard can be eliminated if the air is replaced by an inert gas containing insufficient oxygen to allow ignition. Fuel tank inerting systems using onboard storage of liquid nitrogen to supply the inert gas were demonstrated by the FAA

Manatt

1977-01-01

140

An isotope dilution headspace method with gas chromatography-mass spectrometry for determination of propylene oxide in food.  

PubMed

A method based on isotope dilution headspace and gas chromatography-mass spectrometry was developed for the determination of propylene oxide in foods. Optimum method sensitivity was achieved by the addition of NaCl in water at saturation and with the sample solution incubated at 90 degrees C. The method had good repeatability with relative standard deviations of 6.0, 7.6 and 2.2% at 5, 20 and 40 microg l(-1), respectively. The method was used to determine propylene oxide in 36 selected food composite samples from the 2007 Canadian total diet study. Propylene oxide was not detected in any samples analyzed with an average method detection limit of 0.5 ng g(-1). Hydrolysis of propylene oxide in water was observed as a first-order reaction with a half-life of 15 h at room temperature and less than 10 min at 90 degrees C. This confirms that it is very unlikely to find propylene oxide in foods as consumed due to its volatility and reaction with water. PMID:19680922

Cao, Xu-Liang; Corriveau, Jeannette

2009-04-01

141

Analysis of N-nitrosamines in water by isotope dilution gas chromatography-electron ionisation tandem mass spectrometry.  

PubMed

A method has been developed for the determination of eight N-nitrosamines in drinking water and treated municipal effluent. The method uses solid phase extraction (SPE), gas chromatography (GC) and analysis by tandem mass spectrometry (MS-MS) with electron ionization (EI). The target compounds are N-nitrosodimethylamine (NDMA), N-nitrosomethyethylamine (NMEA), N-nitrosodiethylamine NDEA), N-nitrosodipropylamine (NDPA), N-nitrosodi-n-butylamine (NDBuA), N-nitrosodiphenylamine (NDPhA), N-nitrosopyrrolidine (NPyr), N-nitrosopiperidine (NPip), N-nitrosomorpholine (NMorph). The use of direct isotope analogues for isotope dilution analysis of all analytes ensures accurate quantification, accounting for analytical variabilities that may occur during sample processing, extraction and instrumental analysis. Method detection levels (MDLs) were determined to describe analyte concentrations sufficient to provide a signal with 99% certainty of detection. The established MDLs for all analytes were 0.4-4 ng L(-1) in a variety of aqueous matrices. Sample matrices were observed to have only a minor impact on MDLs and the method validation confirmed satisfactory method stability over intra-day and inter-day analyses of tap water and tertiary treated effluent samples. PMID:22967534

McDonald, James A; Harden, Nick B; Nghiem, Long D; Khan, Stuart J

2012-09-15

142

Atomic-emission spectrometry with an induction-coupled high-frequency plasma source Comparison with the inert-gas shielded premixed nitrous oxide-acetylene flame for multi-element analysis.  

PubMed

The performance for trace analysis in solution by atomic-emission spectrometry from a 36-MHz induction-coupled radiofrequency plasma atom-cell is predicted from a simple model and compared with the corresponding characteristics of an inert-gas shielded nitrous oxide-acetylene flame. A longer linear calibration range is predicted for the plasma source owing to the greater freedom from self-absorption under optimum operating conditions, and the long residence time of analyte species confers freedom from solute vaporization interferences. The predictions are verified experimentally and the advantages of the use of the plasma source are demonstrated in the analysis of aluminium alloys for copper, iron, magnesium, manganese, titanium and zinc. PMID:18961578

Kirkibright, G F; Ward, A F

1974-11-01

143

Quantification of carcinogenic 4- to 6-ring polycyclic aromatic hydrocarbons in human urine by solid-phase microextraction gas chromatography–isotope dilution mass spectrometry  

Microsoft Academic Search

Polycyclic aromatic hydrocarbons (PAHs) are pollutants found in living and working environments. The aim of this study was\\u000a to develop a solid-phase microextraction (SPME) gas chromatography (GC)–isotope dilution mass spectrometry method for the\\u000a quantification of 10 four- to six-ring PAHs in urine samples. Seven of the selected PAHs have been classified as carcinogenic.\\u000a Under the final conditions, analytes were sampled

Laura Campo; Silvia Fustinoni; PierAlberto Bertazzi

144

Simultaneous analysis of urinary phthalate metabolites of residents in Korea using isotope dilution gas chromatography-mass spectrometry.  

PubMed

Phthalates are used in industry products, household items, and medical tools as plasticizers. Human exposure to phthalates has raised concern about its toxicity. In the present study, optimization was conducted for the simultaneous analysis of eight kinds of phthalate metabolites using gas chromatography-mass spectrometry (GC-MS): MEP, MiBP, MnBP, MBzP, MiNP, MEHP, MEOHP, and MEHHP. In order to minimize the matrix effect and to do quantitative analysis, isotope dilution and LLE-GC-MS methods were performed. Urine samples were enzymatically hydrolyzed, extracted with a mixture of n-hexane and ethyl ether (8:2; v:v), and subsequently derivatized with trimethylsilylation. All eight kinds of analytes showed clear resolution and high reproducibility in GC-MS results. The method detection limit ranged from 0.05 ng/mL to 0.2 ng/mL. Calibration curves were found to be linear from 0.2 to 100 ng/mL with -(2)>0.992. The relative standard deviation of the intraday precision using water and urine ranged from 2.1% to 16.3%. The analysis was performed with urine samples that were collected from adults residing in the Republic of Korea. The analyzed concentration results were compared according to gender and region. As a result, DEHP metabolites showed the highest detected concentration (75.92 ?g/g creatinine, 100%), and MiNP, a metabolite of DiNP, showed the lowest detected concentration (0.42 ?g/g creatinine, 22.5%). On average, female urine (200.76 ?g/g creatinine) had a higher detected concentration of ?8 phthalate metabolites than male urine. Samples from rural regions (211.96 ?g/g creatinine) had higher levels than samples from urban regions. PMID:23928369

Kim, Miok; Song, Na Rae; Choi, Jong-Ho; Lee, Jeongae; Pyo, Heesoo

2014-02-01

145

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

E-print Network

-Based Alloys S.W. BANOVIC, J.N. DuPONT, and A.R. MARDER Fusion welds were prepared between a superaustenitic, with quantitative chemical information obtained through electron-probe microanalysis (EPMA). The dilution level

DuPont, John N.

146

Pressurized pyrolysis of rice husk in an inert gas sweeping fixed-bed reactor with a focus on bio-oil deoxygenation.  

PubMed

The pyrolysis of rice husk was conducted in a fixed-bed reactor with a sweeping nitrogen gas to investigate the effects of pressure on the pyrolytic behaviors. The release rates of main gases during the pyrolysis, the distributions of four products (char, bio-oil, water and gas), the elemental compositions of char, bio-oil and gas, and the typical compounds in bio-oil were determined. It was found that the elevation of pressure from 0.1MPa to 5.0MPa facilitated the dehydration and decarboxylation of bio-oil, and the bio-oils obtained under the elevated pressures had significantly less oxygen and higher calorific value than those obtained under atmospheric pressure. The former bio-oils embraced more acetic acid, phenols and guaiacols. The elevation of pressure increased the formation of CH4 partially via the gas-phase reactions. An attempt is made in this study to clarify "the pure pressure effect" and "the combined effect with residence time". PMID:25463787

Qian, Yangyang; Zhang, Jie; Wang, Jie

2014-12-01

147

Solid-phase microextraction and gas chromatography olfactometry analysis of successively diluted samples. A new approach of the aroma extract dilution analysis applied to the characterization of wine aroma.  

PubMed

The relationship between the composition and the aroma of the wine can be established by using gas chromatography with olfactometric detection (sniffing or GCO), which combines the chromatographic response with the human nose response. To evaluate the contribution of the odor compounds in wine aroma, we designed a new approach of the aroma extract dilution analysis (AEDA) that lies in the GCO analysis of serially diluted wine samples using headspace solid-phase microextraction (HS-SPME) as the extraction technique. The fiber coating used was Flex divinyl-carboxen-polydimethylsiloxane. The method developed was applied to determine the aromatic composition of a red Grenache wine from Priorat (Spain). The method allows 38 important odorants to be determined in the AEDA study, 30 of them precisely identified. These results are similar to those reported by other studies related to this variety of wine. HS-SPME is a suitable technique to obtain representative extracts of wine aroma with several advantages such as simplicity, speediness, and little sample manipulation. PMID:14690365

Martí, Maria Pilar; Mestres, Montserrat; Sala, Cristina; Busto, Olga; Guasch, Josep

2003-12-31

148

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

NASA Astrophysics Data System (ADS)

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

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

2012-11-01

149

Dilution-based emissions sampling from stationary sources: Part 2--Gas-fired combustors compared with other fuel-fired systems.  

PubMed

With the recent focus on fine particle matter (PM2.5), new, self-consistent data are needed to characterize emissions from combustion sources. Such data are necessary for health assessment and air quality modeling. To address this need, emissions data for gas-fired combustors are presented here, using dilution sampling as the reference. The dilution method allows for collection of emitted particles under conditions simulating cooling and dilution during entry from the stack into the air. The sampling and analysis of the collected particles in the presence of precursor gases, SO2 nitrogen oxide, volatile organic compound, and NH3 is discussed; the results include data from eight gas fired units, including a dual-fuel institutional boiler and a diesel engine powered electricity generator. These data are compared with results in the literature for heavy-duty diesel vehicles and stationary sources using coal or wood as fuels. The results show that the gas-fired combustors have very low PM2.5 mass emission rates in the range of approximately 10(-4) lb/million Btu (MMBTU) compared with the diesel backup generator with particle filter, with approximately 5 x 10(-3) lb/MMBTU. Even higher mass emission rates are found in coal-fired systems, with rates of approximately 0.07 lb/MMBTU for a bag-filter-controlled pilot unit burning eastern bituminous coal. The characterization of PM2.5 chemical composition from the gas-fired units indicates that much of the measured primary particle mass in PM2.5 samples is organic or elemental carbon and, to a much less extent, sulfate. Metal emissions are quite low compared with the diesel engines and the coal- or wood-fueled combustors. The metals found in the gas-fired combustor particles are low in concentration, similar in concentration to ambient particles. The interpretation of the particulate carbon emissions is complicated by the fact that an approximately equal amount of particulate carbon (mainly organic carbon) is found on the particle collector and a backup filter. It is likely that measurement artifacts, mostly adsorption of volatile organic compounds on quartz filters, are positively biasing "true" particulate carbon emission results. PMID:17269233

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

2007-01-01

150

-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

151

Gas-surface interactions using accommodation coefficients for a dilute and a dense gas in a micro- or nanochannel: Heat flux predictions using combined molecular dynamics and Monte Carlo techniques  

NASA Astrophysics Data System (ADS)

The influence of gas-surface interactions of a dilute gas confined between two parallel walls on the heat flux predictions is investigated using a combined Monte Carlo (MC) and molecular dynamics (MD) approach. The accommodation coefficients are computed from the temperature of incident and reflected molecules in molecular dynamics and used as effective coefficients in Maxwell-like boundary conditions in Monte Carlo simulations. Hydrophobic and hydrophilic wall interactions are studied, and the effect of the gas-surface interaction potential on the heat flux and other characteristic parameters like density and temperature is shown. The heat flux dependence on the accommodation coefficient is shown for different fluid-wall mass ratios. We find that the accommodation coefficient is increasing considerably when the mass ratio is decreased. An effective map of the heat flux depending on the accommodation coefficient is given and we show that MC heat flux predictions using Maxwell boundary conditions based on the accommodation coefficient give good results when compared to pure molecular dynamics heat predictions. The accommodation coefficients computed for a dilute gas for different gas-wall interaction parameters and mass ratios are transferred to compute the heat flux predictions for a dense gas. Comparison of the heat fluxes derived using explicit MD, MC with Maxwell-like boundary conditions based on the accommodation coefficients, and pure Maxwell boundary conditions are discussed. A map of the heat flux dependence on the accommodation coefficients for a dense gas, and the effective accommodation coefficients for different gas-wall interactions are given. In the end, this approach is applied to study the gas-surface interactions of argon and xenon molecules on a platinum surface. The derived accommodation coefficients are compared with values of experimental results.

Nedea, S. V.; van Steenhoven, A. A.; Markvoort, A. J.; Spijker, P.; Giordano, D.

2014-05-01

152

Effects of dilution on methane entering an SOFC anode  

NASA Astrophysics Data System (ADS)

Methane and other hydrocarbons such as propane and butane are ideal fuels for SOFCs operating in portable devices for domestic or leisure use [J. Power Sources 71 (1998) 268]. This paper addresses the fuel entry conditions necessary for such devices. A gas manifold system was connected to a micro-tubular zirconia cell 2 mm diameter with lanthanum strontium manganite cathode and nickel/zirconia/ceria anode. Wire current collectors were used to obtain electrochemical performance data via a potentiostat system. The reaction products from the anode were analysed by mass spectroscopy to elucidate the reaction mechanism, and temperature programmed oxidation allowed the carbon deposition to be evaluated [Proceedings of the 4th European Solid Oxide Fuel Cell Forum, Luzern, July 2001, p.151]. Carbon deposition was substantial near open circuit voltage, when little oxygen was flowing to the anode. Dilution with inert gas or with CO 2 caused a significant change in the reaction mechanism. The conclusion was that diluted methane could be fed directly into the SOFC, and that particular compositions (e.g. biogas at 30% methane and 70% carbon dioxide) gave optimum performance with little carbon fouling.

Kendall, K.; Finnerty, C. M.; Saunders, G.; Chung, J. T.

153

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

154

Analysis of alkyl and 2-6-ringed polycyclic aromatic hydrocarbons by isotope dilution gas chromatography/mass spectrometry. Quality assurance and determination in Spanish river sediments.  

PubMed

An accurate, precise and sensitive method is described for the analysis of 29 polycyclic aromatic hydrocarbons (PAHs), including 19 2-6-ringed PAHs and 10 alkyl-PAHs. The method is based on an isotope dilution technique using gas chromatography/mass spectrometry (GC/MS) and available labeled PAHs as internal standards. Quality parameters were calculated with satisfactory results and 36 Spanish river sediments were analysed. Results were evaluated regarding to the sediment quality guidelines (SQGs) based on the effects range-low (ERL) and the effects range-median (ERM) values. Most analysed sediments showed a good quality, since only 7 of them exceeded ERL values, including one sample surpassing ERM values. PAH profiles were studied in order to identify PAH sources as mainly petrogenic or pyrogenic. Most samples showed petrogenic-type fingerprints, although 6 of the 11 sediments with the highest PAH concentrations (> 1000 ng/g) were classified as pyrogenic, including 4 of the 7 samples exceeding ERL values. Quality assurance was carried out by the triplicate analysis of one preanalysed river sediment without PAHs subsequently spiked at a medium (500 ng/g) and a low concentration level (10 ng/g) of each analyte. Main quality requirements for methods based on isotope dilution were accomplished. Method accuracy was 80-120% for most PAHs, method precision was <15% for all the analysed compounds and method detection limits (MDLs) were 1-3 ng/g. PMID:16513126

Planas, Carles; Puig, Alejandra; Rivera, Josep; Caixach, Josep

2006-04-28

155

Bose-Einstein condensation in a dilute gas: the first 70 years and some recent experiments (Nobel Lecture).  

PubMed

Bose-Einstein condensates of dilute gases offer a rich field to study fundamental quantum-mechanical processes, manipulation of the speed at which light propogates, observation of atomic pair-formation and superfluidity, or even simulating white dwarf stars. Still more radical applications are on the horizon. However, their initial creation was a masterpiece of experimental physics. After an initial process of laser cooling (which itself won its developers the 1997 Nobel Prize), atoms in a magnetic-optical trap must be safely transferred into a purely magnetic trap, where the condensation process begins at 170 nK and 20 nK a pure condensate of 2000 atoms could be created. More astonishingly, Wieman and Cornell showed these low temperatures could be achieved in "bench scale" equipment rather than the massive pieces normally demanded by cryoscience. For their 1995 discovery of this new state of matter, they were awarded the 2001 Nobel Prize in Physics. PMID:12465486

Cornell, Eric A; Wieman, Carl E

2002-06-17

156

Inert gases in a terra sample - Measurements in six grain-size fractions and two single particles from Lunar 20.  

NASA Technical Reports Server (NTRS)

Review of the results of inert gas measurements performed on six grain-size fractions and two single particles from four samples of Luna 20 material. Presented and discussed data include the inert gas contents, element and isotope systematics, radiation ages, and Ar-36/Ar-40 systematics.

Heymann, D.; Lakatos, S.; Walton, J. R.

1973-01-01

157

Free electron in compressed inert gases  

SciTech Connect

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

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

2008-08-15

158

Free electron in compressed inert gases  

NASA Astrophysics Data System (ADS)

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

Gordon, E. B.; Smirnov, B. M.

2008-08-01

159

Adsorption of anionic nanosheets from their dilute colloidal suspensions onto gas-liquid interfaces with and without a Langmuir film of cationic surfactant.  

PubMed

The adsorption of [(Ca(2)Nb(3)O(10))(-)](n) (CNO) polyanionic nanosheets from their dilute colloidal suspensions onto gas-liquid interfaces with and without a cationic [N(CH(3))(2)(C(18)H(37))(2)](+) (DOA) surfactant film has been experimentally investigated. Our concern has been focused particularly on their dynamical aspects, which can be observed owing to the long specific time of the adsorption. The theoretical framework of the Langmuir adsorption model has enabled a quantitative analysis of the observed data, and that analysis has indicated that the presence of a positively charged Langmuir film enhances the ratio of the adsorption and desorption rate constants by approximately 30 times. Furthermore, the experimental results have shown that a "balanced" hybrid Langmuir film, in which both organic and inorganic constituents are densely packed, can be prepared. PMID:20141206

Ikegami, Keiichi; Tetsuka, Hiroyuki; Hoshi, Yasushi; Ebina, Takeo; Takashima, Hiroshi

2010-02-16

160

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

161

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

SciTech Connect

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

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

1985-12-01

162

Identification of odorants in frankincense (Boswellia sacra Flueck.) by aroma extract dilution analysis and two-dimensional gas chromatography-mass spectrometry/olfactometry.  

PubMed

Frankincense has been known, traded and used throughout the ages for its exceptional aroma properties, and is still commonly used in both secular and religious settings to convey a pleasant odor. Surprisingly, the odoriferous principle(s) underlying its unique odor profile have never been published. In this study, resin samples of Boswellia sacra Flueck. from both Somalia and Oman were investigated by aroma extract dilution analysis. In a comprehensive, odor-activity guided approach both chemo-analytical and human-sensory parameters were used to identify odor active constituents of the volatile fraction of B. sacra. Among the key odorants found were ?-pinene, ?-myrcene, linalool, p-cresol and two unidentified sesquiterpenoids. Overall, a total of 23 odorants were detected and analyzed by gas chromatography-olfactometry and heart-cut two-dimensional gas chromatography-mass spectrometry/olfactometry. The majority of the identified odorant compounds were oxygenated monoterpenes, along with some relevant mono- and sesquiterpenes and only one diterpenoid substance. Several of these compounds were reported here for the first time as odorous constituents in B. sacra. Identifying bioactive compounds might support a better understanding with regard to the potential benefits of frankincense, for example in aromatherapy or ecclesial settings. PMID:25468535

Niebler, Johannes; Buettner, Andrea

2015-01-01

163

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

164

Quantification of carcinogenic 4- to 6-ring polycyclic aromatic hydrocarbons in human urine by solid-phase microextraction gas chromatography-isotope dilution mass spectrometry.  

PubMed

Polycyclic aromatic hydrocarbons (PAHs) are pollutants found in living and working environments. The aim of this study was to develop a solid-phase microextraction (SPME) gas chromatography (GC)-isotope dilution mass spectrometry method for the quantification of 10 four- to six-ring PAHs in urine samples. Seven of the selected PAHs have been classified as carcinogenic. Under the final conditions, analytes were sampled with a 100-?m polydimethylsiloxane SPME fibre for 60 min at 80 °C and desorbed in the injection port of the GC at 270 °C. Fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenzo[a,h]anthracene, indeno[1,2,3-cd]pyrene and benzo[ghi]perylene were separated using a highly arylene-modified phase capillary column and quantified by MS using eight deuterated PAHs as surrogate internal standards. Limits of quantification (LOQ) were in the 0.5- to 2.2-ng/L range. Validation showed linear dynamic ranges up to 340 ng/L, inter- and intra-run precisions <20%, and accuracies within 20% of spiked concentrations. Matrix effect evaluation and the use of control charts to monitor process performances showed that the isotope dilution approach allowed for the control of bias sources. Urinary PAHs were above or equal to LOQ, depending on different compounds, in 58-100% (min-max), 40-100% and 5-39% of samples from coke oven workers (n?=?12), asphalt workers (n?=?10) and individuals not occupationally exposed to PAHs (n?=?18), respectively. Chrysene was the most abundant PAH determined with median levels of 62.6, 6.9 and <0.6 ng/L, respectively. These results show that the method is suitable for quantifying carcinogenic PAHs in specimens from individuals with different levels of PAH exposure. PMID:21626187

Campo, Laura; Fustinoni, Silvia; Bertazzi, Pieralberto

2011-08-01

165

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

NASA Technical Reports Server (NTRS)

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

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

1993-01-01

166

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

167

INERT Atmosphere confinement operability test procedure  

Microsoft Academic Search

This Operability Test Procedure (OTP) provides instructions for testing operability of the Inert Atmosphere Confinement (IAC). The Inert Atmosphere Confinement was designed and built for opening cans of metal items that might have hydrided surfaces. Unreviewed Safety Question (USQ) PFP-97-005 addresses the discovery of suspected plutonium hydride forming on plutonium metal currently stored in the Plutonium Finishing Plant vaults. Plutonium

1999-01-01

168

34 JOM May 2001 Inert Anodes  

E-print Network

by their poor thermomechanical properties. At one time, tin oxide was considered a poten- tial inert anode of aluminum production. Research is continuing on materials that would best serve that purpose. Results. Indeed, Charles Martin Hall himself lamented that, in the absence of an inert anode, he feared aluminum

Sadoway, Donald Robert

169

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

Microsoft Academic Search

Dry storage of Zircaloy-clad spent fuel in inert gas (referred to as inerted dry storage or IDS) is being developed as an alternative to water pool storage of spent fuel. The objectives of the activities described in this report are to identify potential Zircaloy degradation mechanisms and evaluate their applicability to cladding breach during IDS, develop models of the dominant

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

1987-01-01

170

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

171

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

172

Development of an equilibrium headspace gas chromatographic method for the measurement of noncovalent association and partitioning of n-alkylbenzenes at infinite dilution in fulvic acid pseudophase.  

PubMed

Fulvic acid (FA), the most important water soluble fraction of humic substances in nature, is known to form aggregate pseudophase and complexes with organic and inorganic species. Here, we report a novel equilibrium headspace gas chromatography (eHSGC) and a two-step reaction model to measure n-alkylbenzene-FA association constant (K11) and n-alkylbenzene-pseudophase FAn association constant (Kn1) without solute concentration and response factor. The K11 and Kn1 values were 2-3 orders of magnitude higher than those for sodium dodecylsulfate. Changes in peak area were used to calculate the critical FA-aggregation concentration (cfc), mole fraction based partition coefficients (Kx), activity coefficients of solute inside the aggregate pseudophase (?m(?)), and transfer free energies of alkyl CH2 at infinite dilution. The cfc was found to be 10±0.5?M. The Kx values are of the order of 10(7) in the FA-aggregate pseudophase. The data shows that benzene has the lowest (0.0002) and n-butylbenzene has the highest (0.01) ?m(?) values, which are seven orders of magnitude smaller than ?w(?) in water. The transfer free energy of association of a CH2 group, -155cal/mol, compared to that of benzene, -9722cal/mol, indicates that the FA-aggregate pseudophase is more polarizable benzene-like and less n-alkane aliphatic-like. PMID:25622521

Eljack, Mahmoud D; Wilson, Rachael E; Hussam, Abul; Khan, Shahamat U

2015-02-27

173

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

SciTech Connect

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

Haag, G.L.

1983-09-01

174

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

175

Axial grading of inert matrix fuels  

SciTech Connect

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

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

2012-07-01

176

7 CFR 201.51 - Inert matter.  

Code of Federal Regulations, 2012 CFR

...categories: (1) Damaged seed (other than grasses) with over one-half of the embryo missing. (2) Grass florets and caryopses classed as inert: (i) Glumes and empty florets of weedy grasses; (ii) Damaged grass caryopses,...

2012-01-01

177

7 CFR 201.51 - Inert matter.  

Code of Federal Regulations, 2011 CFR

...categories: (1) Damaged seed (other than grasses) with over one-half of the embryo missing. (2) Grass florets and caryopses classed as inert: (i) Glumes and empty florets of weedy grasses; (ii) Damaged grass caryopses,...

2011-01-01

178

7 CFR 201.51 - Inert matter.  

Code of Federal Regulations, 2010 CFR

...categories: (1) Damaged seed (other than grasses) with over one-half of the embryo missing. (2) Grass florets and caryopses classed as inert: (i) Glumes and empty florets of weedy grasses; (ii) Damaged grass caryopses,...

2010-01-01

179

7 CFR 201.51 - Inert matter.  

...categories: (1) Damaged seed (other than grasses) with over one-half of the embryo missing. (2) Grass florets and caryopses classed as inert: (i) Glumes and empty florets of weedy grasses; (ii) Damaged grass caryopses,...

2014-01-01

180

7 CFR 201.51 - Inert matter.  

Code of Federal Regulations, 2013 CFR

...categories: (1) Damaged seed (other than grasses) with over one-half of the embryo missing. (2) Grass florets and caryopses classed as inert: (i) Glumes and empty florets of weedy grasses; (ii) Damaged grass caryopses,...

2013-01-01

181

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

182

Inert strength of pristine silica glass fibers  

SciTech Connect

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

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

1993-11-01

183

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

184

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

E-print Network

Mechanisms controlling the global oceanic distribution of the inert gases argon, nitrogen and neon formation. We present argon, nitrogen, and neon data from the subtropical and subpolar North Pacific-mediated gas exchange. This result suggests that these three processes are the first order controls

Emerson, Steven R.

185

Modeling of Axisymmetric Two-phase Dilute Flows  

Microsoft Academic Search

This paper deals with the numerical treatment of Eulerian approach for dilute two-phase compressible flows (gas-particles mixtures) in axisymmetric configurations. For dilute flows, two classes of models depending on the dispersed phase volumetric fraction can be found. The volume occupied by the particles may be considered, that yields a model in which the gas phase and the dispersed phase equations

E. Daniel; R. Saurel; J. C. Loraud

1998-01-01

186

Pressure Effect of Various Inert Gases on the Phase Behavior of Polystyrene-block-Poly(n-pentyl methacrylate) Copolymer  

NASA Astrophysics Data System (ADS)

We investigated the pressure effect of three inert gases (nitrogen, helium and argon) on the phase behavior of polystyrene-block-poly(n-pentylmethacrylate) copolymer (PS-b-PnPMA) showing closed-loop phase behavior and baroplasticity. Helium gas pressure enhanced the miscibility between PS and PnPMA blocks similar to the hydrostatic pressure. Very interestingly, however, with increasing nitrogen and argon gas pressure, the miscibility between the two blocks decreased even though these two are also considered as inert gases. To explain these unexpected results, we measured the amount of gas absorption into each block. The experimentally measured gas absorption results are consistent with the theoretical ones based on the Sanchez-Lacombe theory. The results in this study imply that well-known and widely employed inert gases such as nitrogen and argon could significantly affect the phase behavior of a weakly interacting block copolymer at high pressures.

Moon, Hong Chul; Kim, Hye Jeong; Cho, Junhan; Kim, Jin Kon

2013-03-01

187

Spectroscopic diagnostics of barrier discharge plasmas in mixtures of zinc diiodide with inert gases  

Microsoft Academic Search

The spectral characteristics of the emission of gas discharge atmospheric pressure plasmas in mixtures of zinc diiodide vapor\\u000a with inert gases (He, Ne, Ar, Kr, and Xe) are investigated. The formation of a gas discharge plasma and the excitation of\\u000a the components of a working mixture were performed in a high-frequency (with a repetition frequency of sinusoidal voltage\\u000a pulses of

N. N. Guivan; A. N. Malinin

2005-01-01

188

Report on the source of the electrochemical impedance on cermet inert anodes  

SciTech Connect

the Inert Electrode Program at Pacific Northwest Laboratory (PNL) is supported by the Office of Industrial Processes of the US Department of Energy and is aimed at improving the energy efficiency of Hall-Heroult cells through the development of inert anodes. The inert anodes currently under study are composed of a cermet material of the general composition NiO-NiFe{sub 2}O{sub 4}-Cu. The program has three primary objectives: (a) to evaluate the anode material in a scaled-up, pilot cell facility, (b) to investigate the mechanisms of the electrochemical reactions at the anode surface, and (c) to develop sensors for monitoring anode and/or electrolyte conditions. This report covers the results of a portion of the studies on anode reaction mechanisms. The electrochemical impedances of cermet inert anodes in alumina-saturated molten cryolite as a function of frequency, current density, and time indicated that a significant component of the impedance is due to the gas bubbles produced at the anode during electrolysis. The data also showed a connection between surface structure and impedance that appears to be related to the effects of surface structure on bubble flow. Given the results of this work, it is doubtful that a resistive film contributes significantly to the electrochemical impedances on inert anodes. Properties previously assigned to such a film are more likely due to the bubbles and those factors that affect the properties and dynamics of the bubbles at the anode surface. 12 refs., 16 figs., 3 tabs.

Windisch, C.F. Jr.; Stice, N.D.

1991-02-01

189

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

NASA Technical Reports Server (NTRS)

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

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

1981-01-01

190

Analysis of pesticides and metabolites in Spanish surface waters by isotope dilution gas chromatography/mass spectrometry with previous automated solid-phase extraction Estimation of the uncertainty of the analytical results.  

PubMed

A method based on isotope dilution gas chromatography/mass spectrometry (GC/MS) with automated solid-phase extraction (SPE) is described for the analysis of 32 pesticides and metabolites in surface waters. This approach consist in the use of nine isotopically labelled representative pesticides as internal standards, which allows high accuracy (trueness and precision) and sensitivity for most analysed compounds, as it is required for isotope dilution-based methods. Uncertainties associated with pesticide determination in real samples were estimated using quality assurance/quality control (QA/QC) data. For most pesticides expanded uncertainty was below 40%, according to the commonly established requirements for analytical results. Ninety three Spanish surface waters collected in June-July and September-November 2004 were analysed. Concentration and occurrence of pesticides were evaluated. These parameters were higher in the summer than in the autumn period. In summer four pesticides were found in more than 50% of the analysed samples and four compounds were detected above the concentration level of 1 microg/l (atrazine, terbutylazine, 3,4-dichloroaniline and fenitrothion), while in autumn percentage of detection was below 50% for all pesticides and only one compound (terbutylazine) exceeded 1 microg/l. PMID:16962600

Planas, Carles; Puig, Alejandra; Rivera, Josep; Caixach, Josep

2006-10-27

191

Muco-inert nanoparticle probes and drug carriers  

NASA Astrophysics Data System (ADS)

Mucus coats the exposed surfaces of the eyes and respiratory, gastrointestinal (GI) and cervicovaginal (CV) tracts, and protects mucosal tissues against pathogens and other foreign particulates. Most foreign particles are effectively trapped in mucus through steric and adhesive interactions, and are rapidly eliminated by different mucus clearance mechanisms. Nevertheless, mucus also immobilizes conventional drug and gene carriers, thereby precluding sustained and targeted drug delivery to mucosal sites. Synthetic particles engineered with muco-inert surfaces, and some viruses, can readily penetrate mucus gel, and may serve as useful probes to understand the biophysical barrier properties of mucus. Improved understanding of the mucus barrier could provide insights into methods to enhance drug and gene delivery at mucosal surfaces, as well as understanding the occasional failure of mucus to protect against infection or injury. Recently, muco-inert nanoparticles were developed by conjugating a dense layer of low MW polyethylene glycol to particle surfaces. Since they are slowed only by steric obstruction from the mucus mesh, various sized muco-inert nanoparticles can be used to probe the microstructure and microrheology of mucus. I applied this technique to determine whether the mucus barrier may be altered by exogenous factors, including the presence of detergent, pH changes and synthetic nanoparticles. I first studied the microrheology of native human cervicovaginal mucus (CVM), and found that CVM behaves as a viscoelastic solid at length scales ? 1 microm (preventing large particles from diffusing through) but as a viscoelastic liquid at length scales up to at least 500 nm (allowing smaller particles to diffuse through low viscosity fluid-filled pores). Treating CVM with a nonionic detergent, N9, shifted the viscoelastic liquid-solid transition point to < 200 nm, suggesting hydrophobic interactions between mucin fibers play an important role in regulating the mucus microstructure and consequently the microrheology. Indeed, N9 caused the average mucus pore size to decrease from ˜340 nm to 130 nm. I then looked at the effect of pH on mucus and found that the microstructure of CVM is essentially pH-independent over a broad range of physiological pH. Between pH 4 (the native pH of CVM) and 6--7, the average pore size in the mucus mesh remained unchanged, and between pH 1--2 and 8--9, there was at most a 2-fold drop in the average pore size (likely due to changes in electrostatic vs. hydrophobic interactions between mucin fibers). Finally, I found that mucoadhesive synthetic nanoparticles, at sufficiently high concentrations, can bundle mucin fibers and create large openings in the mucus microstructure. Disruption of the mucus barrier in this manner allowed a greater fraction of large (1 microm) muco-inert particles to diffuse through the mucus mesh. Muco-inert nanoparticles---also referred to as "mucus-penetrating particles" (MPP)---offer the potential for sustained and targeted drug delivery to mucosal surfaces. By penetrating luminal mucus layers, MPP may be able to reach the slowly cleared adherent mucus layer or deep folds of the epithelium and thereby achieve prolonged retention. I first measured the long range penetration of MPP compared to conventional mucoadhesive particles (CP) into CVM. With minimal dilution of CVM, MPP could penetrate up to 200 microm over 1 hr with ˜530 particles/mm2 penetrating 100 microm or more, while CP remained immobilized (note that physiological mucus layer thicknesses are no more than ˜200 microm). Furthermore, with 30% v/v dilution, MPP could penetrate up to 1.5 mm over 1 hr with ˜74,000 particles/mm2 penetrating 100 microm or more, while CP continued to remain stuck. I then studied the distribution and retention of MPP vs. CP in the mouse vagina to determine whether improved mucus penetration leads to more uniform distribution and prolonged retention. I found that MPP were not only more uniformly distributed in the vaginal lumen, but also penetrated deep into epithel

Wang, Ying-Ying

2011-12-01

192

Polyvinyl alcohol battery separator containing inert filler  

SciTech Connect

A cross-linked polyvinyl alcohol battery separator is disclosed. A particulate filler, inert to alkaline electrolyte of an alkaline battery, is incorporated in the separator in an amount of 1-20% by weight, based on the weight of the polyvinyl alcohol, and is dispersed throughout the product. Incorporation of the filler enhences performance and increases cycle life of alkaline batteries when compared with batteries containing a similar separator not containing filler. Suitable fillers include titanates, silicates, zirconates, aluminates, wood floor, lignin, and titania. Particle size is not greater than about 50 microns.

Sheibley, D.W.; Hsu, L.C.; Manzo, M.A.

1981-06-01

193

Infants' individuation of agents and inert objects.  

PubMed

Using the violation-of-expectancy method, we investigated 10-month-old infants' ability to rely on dynamic features in object individuation processes. Infants were first familiarized to events in which two different objects repeatedly appeared and disappeared, one at a time from behind a screen; at test, the screen was removed, revealing either one or two objects. In Experiment 1, one self-moving non-rigid agent and one inert object were involved in each trial, while in Experiment 2 two different agents were presented. Infants preferred to look at one-object outcomes in Experiment 1, but they did not show any preference for one- or two-object outcomes in Experiment 2. The results suggest that infants can use dynamic information to detect agents in complex individuation tasks before they can rely on shape or surface features. We propose that the sortals agent and inert object appear in development before 12 months without a substantial contribution of linguistic experience. These findings may motivate a revision of current theories on the development of kind-based individuation and object files. PMID:20121870

Surian, Luca; Caldi, Stefania

2010-01-01

194

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

195

Mucosal Vaccination against Tuberculosis Using Inert Bioparticles  

PubMed Central

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.

2013-01-01

196

Total synthesis of isotopically enriched Si-29 silica NPs as potential spikes for isotope dilution quantification of natural silica NPs.  

PubMed

A new method was developed for the preparation of highly monodisperse isotopically enriched Si-29 silica nanoparticles ((29)Si-silica NPs) with the purpose of using them as spikes for isotope dilution mass spectrometry (IDMS) quantification of silica NPs with natural isotopic distribution. Si-29 tetraethyl orthosilicate ((29)Si-TEOS), the silica precursor was prepared in two steps starting from elementary silicon-29 pellets. In the first step Si-29 silicon tetrachloride ((29)SiCl4) was prepared by heating elementary silicon-29 in chlorine gas stream. By using a multistep cooling system and the dilution of the volatile and moisture-sensitive (29)SiCl4 in carbon tetrachloride as inert medium we managed to reduce product loss caused by evaporation. (29)Si-TEOS was obtained by treating (29)SiCl4 with absolute ethanol. Structural characterisation of (29)Si-TEOS was performed by using (1)H and (13)C nuclear magnetic resonance (NMR) spectroscopy and Fourier-transform infrared (FTIR) spectroscopy. For the NP preparation, a basic amino acid catalysis route was used and the resulting NPs were analysed using transmission electron microscopy (TEM), small angle X-ray scattering (SAXS), dynamic light scattering (DLS) and zeta potential measurements. Finally, the feasibility of using enriched NPs for on-line field-flow fractionation coupled with multi-angle light scattering and inductively coupled plasma mass spectrometry (FFF/MALS/ICP-MS) has been demonstrated. PMID:25617615

Pálmai, Marcell; Szalay, Roland; Bartczak, Dorota; Varga, Zoltán; Nagy, Lívia Naszályi; Gollwitzer, Christian; Krumrey, Michael; Goenaga-Infante, Heidi

2015-05-01

197

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

198

Neuroprotective and neurotoxic properties of the 'inert' gas, xenon  

Microsoft Academic Search

Background. Antagonists of the N-methyl-D-aspartate (NMDA) subtype of glutamate recep- tors have been shown not only to have neuroprotective effects but also to exhibit neurotoxic properties. In this study, we used c-Fos, a protein product of an immediate early gene, as a marker of neuronal injury to compare the neuroprotective effects of xenon and the neurotoxic properties of xenon, nitrous

D. Ma; S. Wilhelm; M. Maze; N. P. Franks

2002-01-01

199

Electron temperature measurement of tungsten inert gas arcs  

Microsoft Academic Search

In order to make clear the physical grounds of deviations from LTE (Local Thermodynamic Equilibrium) in the atmospheric helium TIG arcs electron temperature and LTE temperature obtained from electron number density were measured by using of line-profile analysis of the laser scattering method without an assumption of LTE. The experimental results showed that in comparison with the argon TIG arcs,

Manabu Tanaka; Shinichi Tashiro

2008-01-01

200

Inert Welding/Brazing Gas Filters and Dryers  

NASA Technical Reports Server (NTRS)

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

Goudy, Jerry

2009-01-01

201

An extended DEM–CFD model for char combustion in a bubbling fluidized bed combustor of inert sand  

Microsoft Academic Search

This paper proposes a transient three-phase numerical model for the simulation of multiphase flow, heat and mass transfer and combustion in a bubbling fluidized bed of inert sand. The gas phase is treated as a continuum and solved using the computational fluid dynamics (CFD) approach; the solid particles are treated as two discrete phases with different reactivity characteristics and solved

Yongming Geng; Defu Che

2011-01-01

202

Phosphorus diffusion in isoconcentration backgrounds under inert conditions in silicon  

E-print Network

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

Florida, University of

203

Tracheal volume in the pupa of the Saturniid moth Hyalophora cecropia determined with inert gases.  

PubMed

Tracheal volume (VTr) was measured in pupae of the Giant silkworm moth Hyalophora cecropia (Saturniidae, Lepidoptera, Insecta) using inert gas wash-out techniques. The animal was placed in a small vessel that was continuously ventilated (rate, V) by a gas mixture containing 20% O2 in N2; the inflowing (F1) and outflowing gas fractions (FE) of the vessel could be continuously measured by a respiratory mass spectrometer. At the onset of a spiracular constriction period, which was evidenced from the FECO2 trace, the mixture was rapidly replaced by pure Ar. At the subsequent burst, the amount of N2 emerging from the animal, MN2, was calculated from V and the difference (FE--F1)N2. VTr was calculated from MN2 and the N2 concentration in the tracheal system before constriction (assumed to equal that in the ventilating gas before replacement by Ar). Measurements were repeated with N2 and Ar replacing each other. VTr average 48 microliter . g-1 (range 39 to 59) for animals of 5.8 g average body weight (range 3.4 to 9.9), when inert gas solubility in body fluids was accounted for. Both size and stage in pupal development appear to affect VTr. These values show reasonable agreement with literature data, mostly obtained by emptying the tracheal gas space by mechanical compression. PMID:6255527

Bridges, C R; Kestler, P; Scheid, P

1980-06-01

204

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

205

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

SciTech Connect

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

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

2006-03-15

206

Growth and development in inert non-aqueous liquids. [of higher plants  

NASA Technical Reports Server (NTRS)

A preview is presented of the survival and growth capabilities of higher plants in non-aqueous, inert liquids. The two media which were used are mineral (white) oil and fluorochemical inert liquid FC-75. Both liquids dissolve oxygen and carbon dioxide readily, but are insoluble in water. Consequently, plants submerged in these liquids are capable of gas exchange with the atmosphere, but possess a water impermeable coating the dimensions of which are determined by the size of the liquid holding container. In a sense, growing plants in a tank of mineral oil imparts on them a cuticle. Plants plus prescribed volumes of water were innoculated into mineral oil. Organisms with minimal water supplied could then be observed. Also, submersed plants covered with an oil slick were shown to be capable of growth in dessicating atmospheres.

Siegel, S. M.

1974-01-01

207

Fuel-dilution effect on differential molecular diffusion in laminar hydrogen diffusion flames  

NASA Astrophysics Data System (ADS)

Laminar flame calculations have been made for a Tsuji counterflow geometry to investigate salient features caused by the differential diffusion effect in nitrogen-diluted hydrogen diffusion flames. A strong dependence of the differential diffusion parameter zHdilution is found, where zHinert gas dilution. This feature causes the differential diffusion parameter to increase with the amount of fuel dilution. The zH

Chen, Yung-cheng; Chen, Jyh-Yuan

1998-12-01

208

Inert Higgs doublet extension of the NMSSM  

NASA Astrophysics Data System (ADS)

We introduce one pair of inert Higgs doublets {Hd,Hu} and singlets {Nc,N}, and consider their couplings with the Higgs doublets of the minimal supersymmetric standard model (MSSM), W ?yNNchuHd+yN'NhdHu. We assign extra U(1)Z' gauge charges only to the extra vectorlike superfields, and so all the MSSM superfields remain neutral under the new U(1)Z'. They can be an extension of the "? term," W ??Shuhd in the next-to MSSM (NMSSM). Because of the U(1)Z', the maximally allowed low energy value of yN can be lifted up to 0.85, avoiding a Landau pole (LP) below the grand unification scale. Such colorless vectorlike superfields remarkably enhance the radiative MSSM Higgs mass particularly for large tan? through the yN term and the corresponding holomorphic soft term. As a result, the lower bound of ? and the upper bound of tan? can be relaxed to disappear from the restricted parameter space of the original NMSSM, 0.6?? ?0.7 and 1

Kyae, Bumseok

2014-04-01

209

Technical basis for storage of Zircaloy-clad spent fuel in inert gases  

SciTech Connect

This report summarizes the technical bases to establish safe conditions for dry storage of Zircaloy-clad fuel. Dry storage of fuel with zirconium alloy cladding has been licensed in Canada, the Federal Republic of Germany, and Switzerland. In addition, dry storage demonstrations, hot cell tests, and modeling have been conducted using Zircaloy-clad fuel. The demonstrations have included irradiated boiling water reactor, pressurized heavy-water reactor, and pressurized water reactor (PWR) fuel assemblies. Irradiated fuel has been emplaced in and retrieved from metal casks, dry wells, silos, and a vault. Dry storage tests and demonstrations have involved {similar_to}5,000 fuel rods, and {similar_to}600 rods have been monitored during dry storage in inert gases with maximum cladding temperatures ranging from 50 to 570{sup 0}C. Although some tests and demonstrations are still in progress, there is currently no evidence that any rods exposed to inert gases have failed (one PWR rod exposed to an air cover gas failed at {similar_to}70{sup 0}C). Based on this favorable experience, it is concluded that there is sufficient information on fuel rod behavior, storage conditions, and potential cladding failure mechanisms to support licensing of dry storage in the United States. This licensing position includes a requirement for inert cover gases and a maximum cladding temperature guideline of 380{sup 0}C for Zircaloy-clad fuel. Using an inert cover gas assures that even if fuel with cladding defects were placed in dry storage, or if defects develop during storage, the defects would not propagate. Tests and demonstrations involving Zircaloy-clad rods and assemblies with maximum cladding temperatures above 400{sup 0}C are in progress. When the results from these tests have been evaluated, the viability of higher temperature limits should be examined. Acceptable conditions for storage in air and dry storage of consolidated fuel are issues yet to be resolved.

Johnson, A.B. Jr.; Gilbert, E.R.

1983-09-01

210

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

211

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

212

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

213

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

214

The Physics and Technology of Dilute Nitrides  

Microsoft Academic Search

Dilute nitrides have emerged from conventional III–V semiconductors such as GaAs or InP by the insertion of nitrogen into the group V sub-lattice, which has a profound influence on the electronic properties of these materials and allows widely extended band structure engineering. This is expected to lead to novel devices, e.g. for optical data transmission, solar cells, biophotonics or gas

N Balkan

2004-01-01

215

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

216

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

217

Optimisation of inert matrix fuel concepts for americium transmutation  

Microsoft Academic Search

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

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

1999-01-01

218

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

219

Dispersion serial dilution methods using the gradient diluter device.  

PubMed

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

Walling, Leslie; Schulz, Craig; Johnson, Michael

2012-12-01

220

Nonequilibrium mechanism of the optical breakdown of inert gases near a refractory target  

NASA Astrophysics Data System (ADS)

Stationary optical breakdown in inert gases near refractory metals exposed to CW CO2-laser radiation is studied analytically and numerically. Consideration is given to surface temperatures at which the ionization equilibrium in the gas/metal vapor mixture is disrupted and the electron distribution function differs from the Maxwellian one (for tungsten the temperature value is 3.5-4.5 kK). The threshold power density is found to depend on the heat of the metal ion evaporation from the surface.

Gladush, G. G.; Iavokhin, A. N.

1985-10-01

221

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

222

Standard dilution analysis.  

PubMed

Standard dilution analysis (SDA) is a novel calibration method that may be applied to most instrumental techniques that will accept liquid samples and are capable of monitoring two wavelengths simultaneously. It combines the traditional methods of standard additions and internal standards. Therefore, it simultaneously corrects for matrix effects and for fluctuations due to changes in sample size, orientation, or instrumental parameters. SDA requires only 200 s per sample with inductively coupled plasma optical emission spectrometry (ICP OES). Neither the preparation of a series of standard solutions nor the construction of a universal calibration graph is required. The analysis is performed by combining two solutions in a single container: the first containing 50% sample and 50% standard mixture; the second containing 50% sample and 50% solvent. Data are collected in real time as the first solution is diluted by the second one. The results are used to prepare a plot of the analyte-to-internal standard signal ratio on the y-axis versus the inverse of the internal standard concentration on the x-axis. The analyte concentration in the sample is determined from the ratio of the slope and intercept of that plot. The method has been applied to the determination of FD&C dye Blue No. 1 in mouthwash by molecular absorption spectrometry and to the determination of eight metals in mouthwash, wine, cola, nitric acid, and water by ICP OES. Both the accuracy and precision for SDA are better than those observed for the external calibration, standard additions, and internal standard methods using ICP OES. PMID:25599250

Jones, Willis B; Donati, George L; Calloway, Clifton P; Jones, Bradley T

2015-02-17

223

Dark Matter with Topological Defects in the Inert Doublet Model  

E-print Network

We examine the production of dark matter by decaying topological defects in the high mass region $m_{\\mathrm{DM}} \\gg m_W$ of the Inert Doublet Model, extended with an extra U(1) gauge symmetry. The density of dark matter states (the neutral Higgs states of the inert doublet) is determined by the interplay of the freeze-out mechanism and the additional production of dark matter states from the decays of topological defects, in this case cosmic strings. These decays increase the predicted relic abundance compared to the standard freeze-out only case, and as a consequence the viable parameter space of the Inert Doublet Model can be widened substantially. In particular, for a given dark matter annihilation rate lower dark matter masses become viable. We investigate the allowed mass range taking into account constraints on the energy injection rate from the diffuse $\\gamma$-ray background and Big Bang Nucleosynthesis, together with constraints on the dark matter properties coming from direct and indirect detection limits. For the Inert Doublet Model high-mass region, an inert Higgs mass as low as $\\sim 200$ GeV is permitted. There is also an upper limit on string mass per unit length, and hence the symmetry breaking scale, from the relic abundance in this scenario. Depending on assumptions made about the string decays, the limits are in the range $10^{12}$ GeV to $10^{13}$ GeV.

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

2014-12-15

224

Gas  

MedlinePLUS

... swallow and the breakdown of undigested food by bacteria in the large intestine. Certain foods may cause gas. Foods that produce gas in one person may not cause gas in another. You can reduce the amount of gas you have by Drinking lots of water and non-fizzy drinks Eating more slowly so ...

225

Comprehensive two-dimensional gas chromatography with isotope dilution time-of-flight mass spectrometry for the measurement of dioxins and polychlorinated biphenyls in foodstuffs. Comparison with other methods.  

PubMed

A comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC x GC-TOF-MS) experimental setup was tested for the measurement of seven 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins (PCDDs), ten 2,3,7,8-substituted polychlorinated dibenzofurans (PCDFs), four non-ortho-polychlorinated biphenyls (PCBs), eight mono-ortho-PCBs, and six indicator PCBs (Aroclor 1260) in foodstuff samples. A 40m RTX-500 (0.18mm I.D., 0.10 microm df) was used as the first dimension (1D) and a 1.5 m BPX-50 (0.10mm I.D., 0.10 microm df) as the second dimension (2D). The GC x GC chromatographic separation was completed in 45 min. Quantification was performed using 13C-label isotope dilution (ID). Isotope ratios of the selected quantification ions were checked against theoretical values prior to peak assignment and quantification. The dynamic working range spanned three orders of magnitude. The lowest detectable amount of 2,3,7,8-TCDD was 0.2 pg. Fish, pork, and milk samples were considered. On a congener basis, the GC x GC-ID-TOF-MS method was compared to the reference GC-ID high resolution mass spectrometry (HRMS) method and to the alternative GC-ID tandem-in-time quadrupole ion storage mass spectrometry (QIST-MS/MS). PCB levels ranged from low picogram (pg) to low nanogram (ng) per gram of sample and data compared very well between the different methods. For all matrices, PCDD/Fs were at a low pg level (0.05-3 pg) on a fresh weight basis. Although congener profiles were accurately described, RSDs of GC x GC-ID-TOF-MS and GC-QIST-MS/MS were much higher than for GC-ID-HRMS, especially for low level pork and milk. On a toxic equivalent (TEQ) basis, all methods, including the dioxin-responsive chemically activated luciferase gene expression (DR-CALUX) assay, produced similar responses. A cost comparison is also presented. PMID:16130655

Focant, Jean-François; Eppe, Gauthier; Scippo, Marie-Louise; Massart, Anne-Cécile; Pirard, Catherine; Maghuin-Rogister, Guy; De Pauw, Edwin

2005-09-01

226

Neutronic aspects of inert matrix fuels for application in ADS  

NASA Astrophysics Data System (ADS)

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

Wallenius, J.

2003-07-01

227

Praxair's dilute oxygen combustion technology for pyrometallurgical applications  

NASA Astrophysics Data System (ADS)

Dilute oxygen combustion (DOC) technology uses separate high-velocity fuel and oxygen jets to generate strong in-furnace gas recirculation, producing combustion between the fuel and a highly diluted oxygen and furnace-gas mixture. These very low NOx oxy-fuel burners have been developed and commercially demonstrated in steel reheating furnaces. The burner design meets industry needs for increased productivity and lower operating costs with minimal capital expense and low maintenance. The performance of DOC technology has been measured under laboratory and industrial conditions encompassing both natural gas and coke oven gas firing, and a wide range of furnace temperatures and nitrogen levels that simulate air infiltration. This paper describes the results of the tests using natural gas as the fuel and lists potential applications for DOC technology in the non-ferrous metals industry.

Riley, M. F.; Kobayashi, H.; Deneys, A. C.

2001-05-01

228

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

229

The Anisotropic Transport Effects on Dilute Plasmas  

NASA Astrophysics Data System (ADS)

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

2011-04-01

230

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

... 2014-07-01 false Dilution air and diluted exhaust flow meters...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES...Measurements § 1065.240 Dilution air and diluted exhaust flow...

2014-07-01

231

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

Microsoft Academic Search

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

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

2011-01-01

232

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

ERIC Educational Resources Information Center

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

Searle, Graeme H.

1985-01-01

233

Combustion of hydrocarbon fuels within porous inert media  

Microsoft Academic Search

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

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

1996-01-01

234

Dark matter with two inert doublets plus one Higgs doublet  

NASA Astrophysics Data System (ADS)

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.

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

2014-11-01

235

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

236

Explosion propagation in inert porous media.  

PubMed

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

Ciccarelli, G

2012-02-13

237

Sea Urchin Embryology: Sperm Dilution  

NSDL National Science Digital Library

Lab directions for up to two 50 min periods and the last of the dilution labs. Includes set up information, materials, procedure, experimental design, things to observe, math possibilities, thought-provoking questions and an assessment.

PhD David Epel (Stanford U. Hopkins Marine Station)

2007-04-20

238

Sea Urchin Embryology: Simple Dilutions  

NSDL National Science Digital Library

Starting from a known concentration students learn to use dilutions to determine the concentration of an unknown. The following skills are used in this lesson: 1. making dilutions 2. reading the meter on a simple homemade spectrophotometer 3. keeping careful laboratory records 4. graphing on linear graph paper 5. determining an unknown concentration from known 6. using a colored filter to enhance contrast and sensitivity

PhD David Epel (Stanford U. Hopkins Marine Station)

2006-12-20

239

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

Microsoft Academic Search

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

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

2011-01-01

240

40 CFR 174.705 - Inert ingredients from sexually compatible plant.  

...PROCEDURES AND REQUIREMENTS FOR PLANT-INCORPORATED PROTECTANTS...ingredients from sexually compatible plant. An inert ingredient...ingredient or leads to the production of the inert ingredient is derived from a plant sexually compatible with...

2014-07-01

241

40 CFR 174.705 - Inert ingredients from sexually compatible plant.  

Code of Federal Regulations, 2011 CFR

...PROCEDURES AND REQUIREMENTS FOR PLANT-INCORPORATED PROTECTANTS...ingredients from sexually compatible plant. An inert ingredient...ingredient or leads to the production of the inert ingredient is derived from a plant sexually compatible with...

2011-07-01

242

40 CFR 174.705 - Inert ingredients from sexually compatible plant.  

Code of Federal Regulations, 2013 CFR

...PROCEDURES AND REQUIREMENTS FOR PLANT-INCORPORATED PROTECTANTS...ingredients from sexually compatible plant. An inert ingredient...ingredient or leads to the production of the inert ingredient is derived from a plant sexually compatible with...

2013-07-01

243

40 CFR 174.705 - Inert ingredients from sexually compatible plant.  

Code of Federal Regulations, 2010 CFR

...PROCEDURES AND REQUIREMENTS FOR PLANT-INCORPORATED PROTECTANTS...ingredients from sexually compatible plant. An inert ingredient...ingredient or leads to the production of the inert ingredient is derived from a plant sexually compatible with...

2010-07-01

244

40 CFR 174.705 - Inert ingredients from sexually compatible plant.  

Code of Federal Regulations, 2012 CFR

...PROCEDURES AND REQUIREMENTS FOR PLANT-INCORPORATED PROTECTANTS...ingredients from sexually compatible plant. An inert ingredient...ingredient or leads to the production of the inert ingredient is derived from a plant sexually compatible with...

2012-07-01

245

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

Federal Register 2010, 2011, 2012, 2013

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

2010-06-01

246

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

SciTech Connect

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

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

2004-10-06

247

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

248

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

SciTech Connect

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

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

2004-10-03

249

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

250

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

251

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

252

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

253

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

SciTech Connect

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

Reppert, T.; Chiu, J.

2005-09-01

254

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

255

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

256

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...

257

Dark Matter with Topological Defects in the Inert Doublet Model  

E-print Network

We examine the production of dark matter by decaying topological defects in the high mass region $m_{\\mathrm{DM}} \\gg m_W$ of the Inert Doublet Model, extended with an extra U(1) gauge symmetry. The density of dark matter states (the neutral Higgs states of the inert doublet) is determined by the interplay of the freeze-out mechanism and the additional production of dark matter states from the decays of topological defects, in this case cosmic strings. These decays increase the predicted relic abundance compared to the standard freeze-out only case, and as a consequence the viable parameter space of the Inert Doublet Model can be widened substantially. In particular, for a given dark matter annihilation rate lower dark matter masses become viable. We investigate the allowed mass range taking into account constraints on the energy injection rate from the diffuse $\\gamma$-ray background and Big Bang Nucleosynthesis, together with constraints on the dark matter properties coming from direct and indirect detectio...

Hindmarsh, Mark; No, Jose Miguel; West, Stephen M

2014-01-01

258

Biomathematical modeling for diluted drugs.  

PubMed

Several workers have proven that succussed ultra high dilution of a drug molecule in water or alcoholic medium, even exceeding Avogadro number, can bring forth noticeable physiological changes of an organism. Homeopathic drugs are prepared by dissolving such drug ingredients in distilled water and then the solution is centesimally diluted serially by ethanol. A mathematical model has been proposed by the present worker, which explains why the drug does not become non-molecular even in ultra-high dilution. This is due to loss of homogeneity in the solution, caused by increase of dielectric constant of the medium during the process of potentization. Facilitated binding of the drug molecules with minute physiologically important protein factors may be the cause of visible physiological alterations. PMID:12781641

Chattopadhyay, S

2003-07-01

259

Effect of Inert, Reducing, and Oxidizing Atmospheres on Friction and Wear of Metals to 1000 F  

NASA Technical Reports Server (NTRS)

Experiments were conducted in inert, reducing, and oxidizing atmospheres to determine their influence on the friction and wear properties of various metals. Nitrogen, argon, forming gas (10 volume percent H2, 90 volume percent N2), and various concentrations of oxygen in nitrogen were used. A 3/16-inch-radius hemispherical rider under a load of 1000 grams contacted the flat surface of a rotating disk. The surface speed employed was 35 feet per minute. The presence of surface oxides is vitally important to the protection of metals in sliding contact. Extremely high friction and excessive wear were encountered in the absence of these oxides. In some instances (electrolytically pure copper), the removal of the surface oxides resulted in mass welding of the specimens in sliding contact. Extremely small quantities of oxygen are sufficient to provide protection of metal surfaces; for example, with 440-C stainless steel, 0.03 volume percent oxygen was found to be adequate.

Buckley, Donald H.; Johnson, Robert L.

1961-01-01

260

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

261

Activity measurement of 85Kr diluted by a large volume balloon technique.  

PubMed

The National Metrology Institute of Japan (NMIJ) participated in the CCRI(II) Key-comparison of (85)Kr activity measurement. The absolute internal gas-counting method was used, with a set of proportional counters of different length. The original (85)Kr gas was diluted by a factor of 2x10(5) in order to achieve the suitable activity concentration for the proportional counters. A new dilution method was introduced, based on a large-volume balloon and gravimetric determination of the dilution volume with small uncertainties. PMID:20056431

Yunoki, Akira; Yamada, Takahiro; Kawada, Yasushi; Unno, Yasuhiro; Sato, Yasushi; Hino, Yoshio

2010-01-01

262

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, the labor market, equality, migration, health, or gender. One goal of the SFB is to integrate these fields

Moeller, Ralf

263

Mobile Melt-Dilute Treatment for Russian Spent Nuclear Fuel  

SciTech Connect

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

Peacock, H.

2002-09-17

264

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

265

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

266

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

267

Dry Dilution Refrigerator with He-4 Precool Loop  

E-print Network

He-3/He-4 dilution refrigerators (DR) are very common in sub-Kelvin temperature research. We describe a pulse tube precooled DR where a separate He-4 circuit condenses the He-3 of the dilution loop. Whereas in our previous work the dilution circuit and the He-4 circuit were separate, we show how the two circuits can be combined. Originally, the He-4 loop with a base temperature of ~ 1 K was installed to make an additional cooling power of up to 100 mW available to cool cold amplifiers and electrical lines. In the new design, the dilution circuit is run through a heat exchanger in the vessel of the He-4 circuit so that the condensation of the He-3 stream of the DR is done by the He-4 stage. A much reduced condensation time (factor of 2) of the He-3/He-4 gas mixture at the beginning of an experiment is achieved. A compressor is no longer needed with the DR as the condensation pressure remains below atmospheric pressure at all times; thus the risk of losing expensive He-3 gas is small. The performance of the DR ...

Uhlig, K

2014-01-01

268

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

269

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

270

Coating crystalline nuclear waste forms to improve inertness  

SciTech Connect

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

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

1981-01-01

271

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

272

Testing New Inert Matrix and Thoria Fuels for Plutonium Incineration  

SciTech Connect

One major issue for nuclear power continues to be the public concern about rad-waste and proliferation risk induced by large plutonium stockpiles accumulated worldwide. In this context, nuclear fuels which exhibit no-plutonium production, and possibly allow for an efficient utilization of the plutonium to get rid of, are of great interest. This is the basic reason for the efforts that many international institutions are devoting to R and D on such new U-free fuel concepts as Inert Matrix (IMF) and Thorium fuels. At the moment the major merit of such innovative fuels is primarily related to the safe closure of the nuclear fuel cycle as especially expected from those new concepts like ADS (Accelerated Driven System) for the transmutation of plutonium, minor actinides and LLFP. Both ceramic inert matrix (IM) and thoria (T) fuels have been identified as suitable to the scope of burning weapon and civilian plutonium and to act also as possible carrier for transmutation of minor actinides. For testing the irradiation behaviour of these new materials, three kinds of fuels have been selected: inert matrix (IM) fuel, inert matrix thoria-doped (IMT) fuel, and thoria (T) fuel. A first experiment, IFA-652, 40 MWD/kg burnup target, including high enriched uranium (HEU) as fissile phase, instead of plutonium, is currently underway in the Halden HWBR. The reason for this choice was that manufacturing of Pu containing fuels is more complex and there was no fabrication facility available at the needed time for the Pu fuel. It is expected, however, that the relative behaviour of the different kind of matrices would be only slightly dependent on the adopted fissile material. So, the comparison of the in-pile performance of the three fuels will constitute a significant common database also for plutonium bearing fuels. The primary aim for the IFA-652 experiment is the measurement of basic characteristics under LWR irradiation conditions over a period of 4-5 years. The design of a second experiment, truly based on plutonium bearing fuel with 80 MWd/kg target burnup, is under preparation. Beyond exploitation in the future transmuters (ADS), the selected fuels are also considered promising candidates for a more effective burning of all kind of plutonium in the present commercial LWRs, what may represent their near term application especially for the weapon Pu stockpile reduction. Most likely this latter aspect is of interest for a wider number of countries which do exploit the benefits of nuclear energy. (authors)

Vettraino, F. [ENEA, Via Martiri di Monte Sole, 4, Bologna 40129 (Italy); Padovan, E. [Politecnico di Milano, Piazza Leonardo da Vinci, 32, 20133 Milano (Italy); Tverberg, T. [OECD Halden Reactor Project, Institut for Energiteknikk, 1751 Halden (Norway)

2002-07-01

273

Gas entrainment allowance level at free surface and gas dynamic behavior of sodium-cooled fast reactor  

Microsoft Academic Search

In a sodium-cooled fast reactor (SFR), inert gases exist in the primary coolant system either in a state of dissolved gas or free gas bubbles. The sources of the gas bubbles are entrainment and dissolution of the reactor cover gas (argon) at the vessel free surface and emission of the helium gas that is produced as a result of disintegration

Akira Yamaguchi; Eisaku Tatsumi; Takashi Takata; Kei Ito; Hiroyuki Ohshima; Hideki Kamide; Jun Sakakibara

2011-01-01

274

Buoyant Response of the Tank 241-SY-101 Crust to Transfer and Back-Dilution  

SciTech Connect

The mixer pump installed in Hanford Tank 241-SY-101 (SY-101) in July 1993 has prevented the large buoyant displacement gas release events (BD GRE) it has historically exhibited. But the absence of periodic disruption from GREs and the action of mixing have allowed the crust to grow. The accelerated gas retention has resulted in over 30 inches of waste level growth and the flammable gas volume stored in the crust has become a hazard. To remediate gas retention in the crust and the potential for buoyant displacement gas releases from below the crust, SY-101 will be diluted in the fall of 1999 to dissolve a large fraction of the solids in the tank. The plan is to transfer waste out and back-dilute with water in several steps of about 100,000 gallons each. Back-dilution water may be added at the transfer pump inlet, the base of the mixer pump, and on top of the crust. The mixer pump will continue to be required to prevent formation of a deep nonconnective layer and resumption of BD GREs. Therefore, it is vital to ensure that the transfer and back-dilution processes do not significantly degrade the pump's effectiveness. Part of the strategy to avoid mixer pump degradation is to keep the base of the crust layer well above the pump inlet, which is 236 inches above the tank bottom. The maximum transfer for which an equal back-dilution is possible without sinking the crust is 90 kgal if water is injected at the 96-inch transfer pump inlet and 120 kgal for injection at the 9-inch mixer pump burrowing ring. To keep the crust base above the lowest observed elevation of 295 inches, transfer and back-dilution must be limited to 143 kgal and 80 kgal, respectively, for the 96-inch back-dilution and 175 kgal with a 112 kgal back-dilution using the 9-inch back-dilution elevation. These limits can be avoided by adding water to the top of the crust to dissolve the negatively buoyant layers. If 20 kgal of water is placed on top of the crust and the rest of the back-dilution is placed under the crust, back-dilution becomes limited by crust sinking at a 128 kgal transfer using the 96-inch injection point and at 160 kgal at 9 inches. The crust base remains well above the 295-inch minimum, and crust base elevation does not limit transfer volume. This result shows that top dilution is very beneficial in providing operational flexibility to the transfer and back-dilution process.

CW Stewart

1999-11-08

275

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

276

Materials research on inert matrices: a screening study  

NASA Astrophysics Data System (ADS)

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

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

1999-08-01

277

Study of a zirconia based inert matrix fuel under irradiation  

NASA Astrophysics Data System (ADS)

Yttria-stabilised zirconia doped with erbia and plutonia has been selected as inert matrix fuel (IMF) at PSI, Switzerland. The results of experimental irradiation experiments on yttria-stabilised zirconia doped with erbia and thoria samples utilising accelerators, tests with yttria-stabilised zirconia doped with plutonia and erbia or urania pellets within research reactors, and a study of natural zirconia contacted to actinide rich rock are evaluated and compared. The results obtained for zirconia implantation with xenon as a representative fission product are analysed in term of swelling and inertness of the material. The reactor tests preformed in the material test Boiling Water Reactor, Halden and in the High Flux Reactor, Petten are also described, with emphasis on the IMF properties under in-pile irradiation. The natural analogue study of baddeleyite from Jacupiranga, southern Brazil, provides additional information. Baddeleyite crystals enclosed within uranpyrochlore grains and received intense irradiation, which did not affect either the structural integrity or the durability of the mineral. The results of these case studies, with accelerator, use in-pile and contacted with natural radioactive sources, provide useful information on the outstanding of the behaviour of zirconia under irradiation.

Degueldre, C.; Hellwig, Ch.

2003-07-01

278

Thermal Conductivity and Sound Attenuation in Dilute Atomic Fermi Gases  

E-print Network

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_c, the quasi-particles are fermions, whereas below T_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 ~ T^{3/2}. In the superfluid phase we find \\kappa ~ T^{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_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.

Matt Braby; Jingyi Chao; Thomas Schaefer

2010-10-15

279

Sea Urchin Embryology: Simple Dilutions 2  

NSDL National Science Digital Library

SUMMARY: Building on what was learned in SIMPLE DILUTION, students will determine the best dilution strategy to solve a dilution problem. 1. Students are given an unknown dye solution and asked to determine its concentration by comparing it with standards they create. 2. Repeated "serial" dilutions will be necessary to determine accurate concentration readings. 3. Varying the color of the filters and the path length will aid in seeing lower concentrations.

PhD David Epel (Stanford U. Hopkins Marine Station)

2006-12-20

280

40 CFR 1065.715 - Natural gas.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Natural gas. 1065.715 Section...Test Fuels, Analytical Gases and Other Calibration...1065.715 Natural gas. (a) Except as...Specifications for Natural Gas Item Value 1 Methane...001 mol/mol. Inert gases (sum of CO2 and...

2010-07-01

281

Clamp and Gas Nozzle for TIG Welding  

NASA Technical Reports Server (NTRS)

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

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

1982-01-01

282

Fabrication and characterization of inert-substrate-supported tubular single cells by dip-coating process  

NASA Astrophysics Data System (ADS)

A tubular single cell supported by an inert substrate with a configuration of porous yttria-stabilized zirconia (YSZ) supporter/Ni anode current collector/Ni-Ce0.8Sm0.2O1.9 anode/YSZ/Ce0.8Sm0.2O1.9 bi-layer electrolyte/La0.6Sr0.4Co0.2Fe0.8O3-? cathode has been fabricated by a cold isostatic pressing and dip-coating process. The effects of pore morphology and porosity of the YSZ supporter on the mechanical strength and electrochemical performance of the single cell have been investigated with respect to the content of poly (methyl methacrylate) (PMMA) pore former. The average pore size and porosity of the YSZ supporter increase with the amount of pore former used, facilitating the gas diffusion process at the anode and reducing the polarization resistance of the single cell whereas leading to a decline of the mechanical strength. A preferred pore former content is determined to be 25 wt.% based on a trade-off of the mechanical strength and electrochemical performance. The single cell with 25 wt.% PMMA in YSZ supporter shows a bending strength of 21 ± 1 MPa and a maximum power density of 337 mW cm-2 at 800 °C in hydrogen. Moreover, the inert-substrate-supported tubular single cell displays a satisfactory redox cycling stability, maintaining 95% of its initial performance within seven redox cycles.

Zhao, Kai; Kim, Bok-Hee; Xu, Qing; Ahn, Byung-Guk

2014-01-01

283

Science Notes: Dilution of a Weak Acid  

ERIC Educational Resources Information Center

This "Science note" arose out of practical work involving the dilution of ethanoic acid, the measurement of the pH of the diluted solutions and calculation of the acid dissociation constant, K[subscript a], for each diluted solution. The students expected the calculated values of K[subscript a] to be constant but they found that the…

Talbot, Christopher; Wai, Chooi Khee

2014-01-01

284

Development of a compact dilution refrigerator for zero gravity operation  

NASA Technical Reports Server (NTRS)

A compact dilution refrigerator design based on internal charcoal adsorption is being tested for operation in zero gravity. This refrigerator is self-contained with no external pumps or gas handling system and provides reliable operation since it has no moving parts. All operations are performed with heaters and are completely computer controlled. The refrigerator is capable of providing many hours of operation at very low temperature before the charcoal pumps must be recycled.

Roach, Pat R.; Helvensteijn, Ben

1990-01-01

285

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

286

Modeling the Dispersion of Inert Particles Using the SAQM Model  

NASA Astrophysics Data System (ADS)

Cities throughout the U.S are subject to the emission of particulate matter (PM) into the atmosphere from a variety of sources. The impact of these emissions has been studied extensively in for regulatory compliance in the area of health effects, air quality and visibility. Little work has been done to study the fate and transport of the inert particulate matter within the El Paso-Juarez Airshed. The Environmental Physics Group at The University of Texas at El Paso has recently applied the SARMAP Air Quality Model (SAQM) to model the dispersion of inert particulate matter in the El Paso-Juarez Airshed. The meteorological data for the SAQM was created with the Penn State/NCAR meteorological modeling system, version 5 (MM5). The SAQM was used to simulate two common occurrences for large particulate emission and concentration. The first was periods of heavy traffic volume at the international bridges which cause large numbers of cars to sit, with engines running, for extended periods of time. The second was moderate to high wind events that cause large amounts of coarse particulate matter to become entrained in the atmosphere and transported into and around the region. Output from the MM5 was used as the meteorological driver for the SAQM. The MM5 was initialized with data from the NCAR reanalysis project. Meteorological data collected in the region by the Texas Commission on Environmental Quality (TCEQ) and by EPA was used for Four Dimensional Data Assimilation. The MM5 was nudged with gridded, surface and observational data. Statistical analysis was done on the MM5 for the variables, wind speed, wind direction, temperature and mixing ratio. The statistics performed included RMSE, RMSEs, RMSEu and index of agreement SAQM was applied to the domain with grid cell sizes of 1.3 km per side. Temporal comparisons were done between EPA's PM2.5 to identify similarities in the evolution of the SAQM with observation. The experience gained in this work will facilitate further studies of dispersion of inert particles throughout other U.S Southwest cities.

Pearson, R.; Fitzgerald, R. M.

2005-12-01

287

Flow characterization and dilution effects of N2 and CO2 on premixed CH4/air flames in a swirl-stabilized combustor  

NASA Astrophysics Data System (ADS)

Numerically-aided experimental studies are conducted on a swirl-stabilized combustor to investigate the dilution effects on flame stability, flame structure, and pollutant emissions of premixed CH4/air flames. Our goal is to provide a systematic assessment on combustion characteristics in diluted regimes for its application to environmentally-friendly approaches such as biogas combustion and exhaust-gas recirculation technology. Two main diluting species, N2 and CO2, are tested at various dilution rates. The results obtained by means of optical diagnostics show that five main flame regimes can be observed for N2-diluted flames by changing excess air and dilution rate. CO2-diluted flames follow the same pattern evolution except that all the domains are shifted to lower excess air. Both N2 and CO2 dilution affect the lean blowout (LBO) limits negatively. This behavior can be counter-balanced by reactant preheating which is able to broaden the flammability domain of the diluted flames. Flame reactivity is degraded by increasing dilution rate. Meanwhile, flames are thickened in the presence of both diluting species. NOx emissions are significantly reduced with dilution and proved to be relevant to flame stability diagrams: slight augmentation in NOx emission profiles is related to transitional flame states where instability occurs. Although dilution results in increase in CO emissions at certain levels, optimal dilution rates can still be proposed to achieve an ideal compromise.

Han, Yue; Cai, Guo-Biao; Wang, Hai-Xing; Renou, Bruno; Boukhalfa, Abdelkrim

2014-03-01

288

Advances in the study of striations in inert gases  

NASA Astrophysics Data System (ADS)

We present a review of studies of striations in a dc discharge in inert gases over recent decades. Physical mechanisms of stratification are described for various discharge conditions. Main attention is paid to striations at low pressures and small currents ( S, P, and R striations). The origin of these striations is associated with electron bunching in spatially periodic resonant fields. The idea of this mechanism and qualitative interpretation of the S and P striations based on the analytic theory are described in the pioneering work by L.D. Tsendin (1982). We describe the evolution of these ideas on quantitative level. New ideas concerning nonintegral resonances responsible for the formation of R striations are considered. The theory is compared with experiment.

Golubovskii, Yu. B.; Nekuchaev, V. O.; Skoblo, A. Yu.

2014-12-01

289

Waste gas storage  

NASA Technical Reports Server (NTRS)

Method for storing a waste gas mixture comprised of nitrogen, oxygen, carbon dioxide, and inert gases, the gas mixture containing corrosive contaminants including inorganic acids and bases and organic solvents, and derived from space station operations. The gas mixture is stored under pressure in a vessel formed of a filament wound composite overwrap on a metal liner, the metal liner being pre-stressed in compression by the overwrap, thereby avoiding any tensile stress in the liner, and preventing stress corrosion cracking of the liner during gas mixture storage.

Vickers, Brian D. (Inventor)

1994-01-01

290

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

291

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

292

Determination of selected monohydroxy metabolites of 2-, 3- and 4-ring polycyclic aromatic hydrocarbons in urine by solid-phase microextraction and isotope dilution gas chromatography–mass spectrometry  

Microsoft Academic Search

Eighteen monohydroxy polycyclic aromatic hydrocarbon metabolites (OH-PAHs) representing polycyclic aromatic hydrocarbons (PAHs) containing up to four rings in human urine have been measured. The method includes the addition of carbon-13 labeled internal standards, enzymatic hydrolysis, and solid-phase microextraction followed by gas chromatography with high-resolution mass spectrometry. By using response factors calculated with the carbon-13 labeled standards, results are presented for

Christopher J. Smith; Charisse J Walcott; Wenlin Huang; Vince Maggio; James Grainger; Donald G Patterson

2002-01-01

293

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

Microsoft Academic Search

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

Gerd Schmalisch; Hans Proquitté; Mario Schmidt; Mario Rüdiger; Roland R. Wauer

2005-01-01

294

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

295

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

296

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

297

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

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

2014-07-01

298

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

299

Combining stakeholder analysis and spatial multicriteria evaluation to select and rank inert landfill sites  

Microsoft Academic Search

This paper presents a method based on the combination of stakeholder analysis and spatial multicriteria evaluation (SMCE) to first design possible sites for an inert landfill, and then rank them according to their suitability. The method was tested for the siting of an inert landfill in the Sarca’s Plain, located in south-western Trentino, an alpine region in northern Italy. Firstly,

Davide Geneletti

2010-01-01

300

Chemical analysis of high temperature gas-cooled reactor fuel material  

Microsoft Academic Search

High temperature gas-cooled reactor fuel material is inert and difficult to analyze chemically. In this report, four methods are reviewed for the analysis of this material, including two salt fusion methods, a chlorination method and a high precision grind-burn-leach method. In the grind-burn-leach method HTGR fuel samples are ground under an inert liquid. The inert liquid is subsequently separated by

Hedrick

1976-01-01

301

A Microgravity Helium Dilution Cooler  

NASA Technical Reports Server (NTRS)

We are developing a He-3-He-4 dilution cooler to operate in microgravity. It uses charcoal adsorption pumps and heaters for its operation; it has no moving parts. It currently operates cyclically to well below 0.1 K and we have designed a version to operate continuously. We expect that the continuous version will be able to provide the long-duration cooling that many experiments need at temperatures down to 0.040 K. More importantly, such a dilution cooler could provide the precooling that enables the use of adiabatic demagnetization techniques that can reach temperatures below 0.001 K. At temperatures below 0.002 K many fascinating microgravity experiments on superfluid He-3 become possible. Among the possibilities are: research into a superfluid He-3 gyroscope, study of the nucleation of the B-phase of superfluid He-3 when the sample is floating out of contact with walls, study of the anisotropy of the surface tension of the B-phase, and NMR experiments on tiny free-floating clusters of superfluid He-3 atoms that should model the shell structure of nuclei.

Roach, Pat R.; Sperans, Joel (Technical Monitor)

1994-01-01

302

Dilute Acid and Autohydrolysis Pretreatment  

NASA Astrophysics Data System (ADS)

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

Yang, Bin; Wyman, Charles E.

303

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

SciTech Connect

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

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

1990-04-01

304

Pulse Tube Coolers with an Inertance Tube: Theory, Modeling and Practice  

NASA Technical Reports Server (NTRS)

We have studied the advantages to be gained by replacing the conventional orifice of a pulse tube cooler by an inertance tube - a long thin tube that introduces the possibility for additional phase shift between pressure and mass flow in the pulse tube section. The case for the use of an inertance tube is most clearly made with an electrical analogy where the 'inductance' added by the inertance tube allows for optimal power transfer at the cold heat exchanger. Detailed modeling of a pulse tube system with an inertance tube confirms these advantages. Comparison between a laboratory cooler with an orifice and with an inertance tube will be presented and reasons wily it is difficult to realize all the expected gain will be given.

Roach, Pat R.; Kashani, Ali; McCreight, Craig R. (Technical Monitor)

1997-01-01

305

Improved Assembly for Gas Shielding During Welding or Brazing  

NASA Technical Reports Server (NTRS)

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

Gradl, Paul; Baker, Kevin; Weeks, Jack

2009-01-01

306

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

307

An assessment of the dilution required to mitigate Hanford tank 241-SY-101  

SciTech Connect

A group of experts from PNL and WHC convened November 2 and 3, 1994, to screen the current state of knowledge about dilution and reach a consensus on the minimum dilution ratio that will achieve passive mitigation of Tank 241-SY-101 wastes and the dilution ratio that would satisfy the given cross-site transfer criteria with reasonable assurance. The panel evaluated the effects of dilution on the parameters important in gas generation, retention, and release and reached the following conclusions, which are deduced from the existing body of data, experience, and analyses: (1) Dissolution of solids is the single most important aspect of mitigation by dilution. We are confident that diluting until nitrates, nitrites, and aluminum salts are dissolved will mitigate Hanford flammable gas tanks; (2) Sufficient solids dissolution can be achieved in Tank 241-SY-101 at a dilution ratio of 1:1, which will result in a average specific gravity of approximately 1.35. It is likely that a 0.5:1 dilution will also mitigate 241-SY-101, but the current uncertainty is too high to recommend this dilution ratio; (3) The recommended dilution requires a diluent with at least 2 molar free hydroxide, because aluminum probably precipitates at lower hydroxide concentrations. The transfer criteria for Tank 241-SY-101 waste were also evaluated. These criteria have been specified as solids content {<=}30% (volume), viscosity {<=}30% cP and density <1.5 g/mL. (1) Solids content is the limiting criterion if it is defined as volume fraction of settled solids. A 1:1 dilution will satisfy this criterion at nominal premixing conditions in Tank 241-SY-101; however, analysis of Window E core samples suggests that up to 1.5:1 might be required. If the solids content is interpreted simply as solids volume fraction no further dilution is necessary, because Tank 241-SY-101 waste (excluding the crust) is already below 30%; (2) Bulk density is the next limiting criterion and is met at 0.4:1 dilution.

Hudson, J.D.; Bredt, P.R.; Felmy, A.R.; Stewart, C.W.; Tingey, J.M.; Trent, D.S. [Pacific Northwest Lab., Richland, WA (United States); Barney, G.S.; Herting, D.L.; Larrick, A.P.; Reynolds, D.A. [Westinghouse Hanford Co., Richland, WA (United States)

1995-02-01

308

Dry dilution refrigerator with He-4 precool loop  

SciTech Connect

He-3/He-4 dilution refrigerators (DR) are very common in sub-Kelvin temperature research. We describe a pulse tube precooled DR where a separate He-4 circuit condenses the He-3 of the dilution loop. Whereas in our previous work the dilution circuit and the He-4 circuit were separate, we show how the two circuits can be combined. Originally, the He-4 loop with a base temperature of ? 1 K was installed to make an additional cooling power of up to 100 mW available to cool cold amplifiers and electrical lines. In the new design, the dilution circuit is run through a heat exchanger in the vessel of the He-4 circuit so condensation of the He-3 stream of the DR is done by the He-4 stage. A much reduced condensation time (factor of 2) of the He-3/He-4 gas mixture at the beginning of an experiment is achieved. A compressor is no longer needed with the DR as the condensation pressure remains below atmospheric pressure at all times; thus the risk of losing expensive He-3 gas is small. The performance of the DR has been improved compared to previous work: The base temperature of the mixing chamber at a small He-3 flow rate is now 4.1 mK; at the highest He-3 flow rate of 1.2 mmol/s this temperature increases to 13 mK. Mixing chamber temperatures were measured with a cerium magnesium nitrate (CMN) thermometer which was calibrated with a superconducting fixed point device.

Uhlig, Kurt [Walther-Meissner-Institute, 85748 Garching (Germany)

2014-01-29

309

Dry dilution refrigerator with He-4 precool loop  

NASA Astrophysics Data System (ADS)

He-3/He-4 dilution refrigerators (DR) are very common in sub-Kelvin temperature research. We describe a pulse tube precooled DR where a separate He-4 circuit condenses the He-3 of the dilution loop. Whereas in our previous work the dilution circuit and the He-4 circuit were separate, we show how the two circuits can be combined. Originally, the He-4 loop with a base temperature of ˜ 1 K was installed to make an additional cooling power of up to 100 mW available to cool cold amplifiers and electrical lines. In the new design, the dilution circuit is run through a heat exchanger in the vessel of the He-4 circuit so condensation of the He-3 stream of the DR is done by the He-4 stage. A much reduced condensation time (factor of 2) of the He-3/He-4 gas mixture at the beginning of an experiment is achieved. A compressor is no longer needed with the DR as the condensation pressure remains below atmospheric pressure at all times; thus the risk of losing expensive He-3 gas is small. The performance of the DR has been improved compared to previous work: The base temperature of the mixing chamber at a small He-3 flow rate is now 4.1 mK; at the highest He-3 flow rate of 1.2 mmol/s this temperature increases to 13 mK. Mixing chamber temperatures were measured with a cerium magnesium nitrate (CMN) thermometer which was calibrated with a superconducting fixed point device.

Uhlig, Kurt

2014-01-01

310

Turbulence in Dilute Polymer Solutions  

NASA Astrophysics Data System (ADS)

We report measurements of particle trajectories in bulk turbulence of Re < 3200 for a dilute polymer solution of polyethylene oxide or polyacrylamide in water. Dissipation range Lagrangian statistics such as the rms acceleration of fluid particles and the acceleration autocorrelation are extracted from the trajectories. We compare these statistics with those for pure water. At high enough Re we find the rms acceleration for the polymer solution to be significantly less than that of water. The acceleration autocorrelation function decays more slowly for the polymer solution which indicates a change in the small scales of turbulence. More information is available at http:// milou.msc.cornell.edu/turbulence.html. This work is supported by the NSF under grant PHY9988755.

Mordant, Nicholas; Crawford, Alice; Laporta, Arthur; Bodenschatz, Eberhard

2002-03-01

311

Band anticrossing in dilute nitrides  

SciTech Connect

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

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

2003-12-23

312

Metal ion implantation in inert polymers for strain gauge applications  

NASA Astrophysics Data System (ADS)

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

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

2010-10-01

313

Inert Doublet Model with a 125 GeV Higgs  

E-print Network

A 125 GeV Higgs-like particle discovered at the LHC in 2012 has properties expected for it in the Standard Model (SM), with a possible enhancement in the two-photon channel. Such SM-like Higgs scenario can be realized within the Inert Doublet Model (IDM) - a version of the Two Higgs Doublet Model with an exact discrete D (Z_2-type) symmetry. In this model one SU(2) doublet plays the role of the SM Higgs doublet with one SM-like Higgs boson. The second doublet has no vacuum expectation value and does not interact with fermions. Among four scalars constituting this D-odd doublet the lightest one is stable, being if neutral a good DM candidate with the right relic density. In this paper an analysis of the two-photon Higgs decay rate in IDM, respecting theoretical and other experimental constraints, is presented. The enhancement in the two-photon channel is possible only if invisible channels are closed, with the enhancement R_{\\gamma \\gamma}>1.2 for masses of DM and charged scalars below 154 GeV. The temperature...

Krawczyk, Maria; Swiezewska, Bogumila

2013-01-01

314

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

315

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

316

Determining inert content in coal dust/rock dust mixture  

DOEpatents

A method and apparatus for determining the inert content of a coal dust and rock dust mixture uses a transparent window pressed against the mixture. An infrared light beam is directed through the window such that a portion of the infrared light beam is reflected from the mixture. The concentration of the reflected light is detected and a signal indicative of the reflected light is generated. A normalized value for the generated signal is determined according to the relationship .phi.=(log i.sub.c `log i.sub.co) / (log i.sub.c100 -log i.sub.co) where i.sub.co =measured signal at 0% rock dust i.sub.c100 =measured signal at 100% rock dust i.sub.c =measured signal of the mixture. This normalized value is then correlated to a predetermined relationship of .phi. to rock dust percentage to determine the rock dust content of the mixture. The rock dust content is displayed where the percentage is between 30 and 100%, and an indication of out-of-range is displayed where the rock dust percent is less than 30%. Preferably, the rock dust percentage (RD%) is calculated from the predetermined relationship RD%=100+30 log .phi.. where the dust mixture initially includes moisture, the dust mixture is dried before measuring by use of 8 to 12 mesh molecular-sieves which are shaken with the dust mixture and subsequently screened from the dust mixture.

Sapko, Michael J. (Finleyville, PA); Ward, Jr., Jack A. (Oakmont, PA)

1989-01-01

317

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

NASA Astrophysics Data System (ADS)

Zirconium carbide is being actively considered for use as an inert matrix material in composite nuclear fuel for gas-cooled fast reactors. ZrC can be produced either by the endothermic carbothermal reduction of zirconium dioxide or by the direct exothermic reaction of pure zirconium and graphite powder mixtures. The exothermic reaction is classified as combustion synthesis or self heating synthesis. Experiments were conducted to demonstrate the combustion synthesis reaction of zirconium and graphite powders and measure the ignition and adiabatic temperatures. The heat released during this short reaction time was sufficient only to partially sinter the compacts to less than 40% theoretical density. Subsequently, compacts of ZrC were similarly produced by combustion synthesis followed by a short, high temperature hold at 2440 °C to relieve residual stresses in the compacts following the rapid reaction sintering. External pressures of up to 5.2 MPa were used as an additional driving force for sintering. The effects of reactant particle size and degree of uniaxial pressing on the product density and porosity were also studied. Higher densities in the fabricated compacts were noted for higher uniaxial pressures irrespective of powder size. Also, smaller powder sizes produced compacts up to 92% TD, while larger particle sizes produced compacts up to 84% TD for the same pressure. The compacts were characterized based on composition, microstructure, and density/porosity. Results of the different experiments are presented.

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

2008-02-01

318

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

SciTech Connect

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

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

1987-10-01

319

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

320

Composition suitable for use as inert electrode having good electrical conductivity and mechanical properties  

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 metals or 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.

Ray, Siba P. (Plum Boro, PA); Rapp, Robert A. (Columbus, OH)

1984-01-01

321

Composition suitable for use as inert electrode having good electrical conductivity and mechanical properties  

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 metals or 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. 8 figs.

Ray, S.P.; Rapp, R.A.

1984-06-12

322

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

DOEpatents

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

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

2000-01-01

323

Results of Waste Transfer and Back-Dilution in Tanks 241-SY-101 and 241-SY-102  

SciTech Connect

This report chronicles the process of remediation of the flammable gas hazard in Tank 241-SY-101 (SY-101) by waste transfer and back-dilution from December 18, 1999 through April 2, 2000. A brief history is given of the development of the flammable gas retention and release hazard in this tank, and the transfer and dilution systems are outlined. A detailed narrative of each of the three transfer and dilution campaigns is given to provide structure for the balance of the report. Details of the behavior of specific data are then described, including the effect of transfer and dilution on the waste levels in Tanks SY-101 and SY-102, data from strain gauges on equipment suspended from the tank dome, changes in waste configuration as inferred from neutron and gamma logs, headspace gas concentrations, waste temperatures, and the mixerpump operating performance. Operating data and performance of the transfer pump in SY-101 are also discussed.

LA Mahoney; ZI Antoniak; WB Barton; JM Conner; NW Kirch; CW Stewart; BE Wells

2000-07-26

324

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

SciTech Connect

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

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

1993-10-01

325

Turbulence of Dilute Polymer Solution  

E-print Network

In fully developed three dimensional fluid turbulence the fluctuating energy is supplied at large scales, cascades through intermediate scales, and dissipates at small scales. It is the hallmark of turbulence that for intermediate scales, in the so called inertial range, the average energy flux is constant and independent of viscosity [1-3]. One very important question is how this range is altered, when an additional agent that can also transport energy is added to the fluid. Long-chain polymers dissolved at very small concentrations in the fluid are such an agent [4,5]. Based on prior work by de Gennes and Tabor [6,7] we introduce a theory that balances the energy flux through the turbulent cascade with that of the energy flux into the elastic degrees of freedom of the dilute long-chain polymer solution. We propose a refined elastic length scale, $r_\\varepsilon$, which describes the effect of polymer elasticity on the turbulence energy cascade. Our experimental results agree excellently with this new energy ...

Xi, Heng-Dong; Xu, Haitao

2013-01-01

326

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

327

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

328

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

329

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

DOEpatents

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

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

2002-01-01

330

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

E-print Network

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

Medvedev, Pavel

2005-02-17

331

Reduced Gravity Combustion of Propanol Droplets in Oxygen-Inert Environments  

Microsoft Academic Search

Reduced gravity combustion experiments were performed with individual fiber-supported propanol droplets that were initially about 1 mm in diameter. The environment was composed of an oxygen-inert mixture. Helium, argon, xenon, nitrogen, and carbon dioxide were used as inerts, the oxygen mole fraction was 0.21, and the pressure was 0.03, 0.1, or 0.3 MPa. Use of helium caused extinction at 0.03 MPa and 0.1 MPa,

J. B. Wei; B. D. Shaw

2009-01-01

332

Uv/vis Absorption Experiments on Mass Selected Cations by Counter-Ion Introduction Into AN Inert Neon Matrix  

NASA Astrophysics Data System (ADS)

Obtaining UV/Vis absorption spectra of cations is a challenging endeavor due to the low densities that can be achieved in the gas phase. In matrix isolation, ions of interest are accumulated in a cold inert matrix of a rare gas (e.g. Argon, Neon) until sufficient concentrations are attained for direct spectroscopic characterization. Nonetheless, in order to ensure neutralization of the matrix, experimentalists often rely on non-ideal, energetic processes, such as electron emission from metal surfaces upon cation bombardment. A better method for matrix neutralization would involve co-depositing a molecular counter-ion. In this talk, a two-ion source instrument is presented, where cations and anions are deposited into a cold inert matrix. Mass-selected cation beams are generated in an electron ionization source and filtered in a quadrupole mass filter (5-10 nA mass-selected naphthalene radical cations recorded). Anion beams are generated in a chemical ionization source (20 nA SF6- recorded). Both ion beams are introduced into an octopole ion guide via a quadrupole deflector. Cations and anions can be deposited simultaneously or separately; in the latter case, alternating layers of each species can be formed. Target cations of interest include open-shell naphthalene and tetracene, for which UV/Vis absorption spectra are recorded after deposition. The counter-ion of choice is SF6-, due to the high electronegativity of SF6. J. P. Maier, et al., J. Chem. Phys. 90, 600(1989). Godbout, et al., J. Phys. Chem. 100 2892-2899(1996). P. Brechignac, et al., J. Chem. Phys. 22 7337-7347(1999). M. Vala, et al., Chem. Phys. Lett. 245 539-548(1995).

Roehr, N. P.; Szczepanski, J.; Polfer, N. C.

2012-06-01

333

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

334

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

335

21 CFR 864.5240 - Automated blood cell diluting apparatus.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 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...

2012-04-01

336

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

337

21 CFR 864.5240 - Automated blood cell diluting apparatus.  

...2014-04-01 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...

2014-04-01

338

A new method for municipal solid waste incinerator (MSWI) fly ash inertization, based on colloidal silica.  

PubMed

Municipal solid waste incineration (MSWI) is a straightforward way to manage waste, however the disposal of process byproducts, mainly bottom and fly ash, is still a problem, because of their hazardous contents. Fly ash is a byproduct of many other processes that involve combustion to produce energy. In this paper we present and discuss a new method for MSWI fly ash inertization, mainly based on the use of colloidal silica as a stabilization agent for metals. In the patented procedure, fly ash of different provenance can be used to produce an inert and non-hazardous material, that can be reused. In fact to make the recovery process more efficient, landfilling should be totally avoided. For this reason, to enhance the possibility of reuse, a washing process, for salts recovery, is proposed as a final step of the inertization procedure. The obtained inert material is called COSMOS (COlloidal Silica Medium to Obtain Safe inert), and it is composed of calcium carbonate, calcium sulfate, silicon oxide and a wide quantity of non-soluble amorphous compounds. COSMOS does not contain any corrosive salts. This makes it extremely interesting for cement industry applications with several other advantages, and environmental benefits. The new proposed inertization procedure appears very promising, because it allows MSWI fly ash to be considered a valuable resource. Thanks to the obtained results, a demonstration project, in the frame of LIFE+, has been funded by the European Commission (LIFE+ 2008 project ENV/IT/000434, ). PMID:20959931

Bontempi, E; Zacco, A; Borgese, L; Gianoncelli, A; Ardesi, R; Depero, L E

2010-11-01

339

Comparison of dilution effects of R134a and nitrogen on flammable hydrofluorocarbons  

NASA Astrophysics Data System (ADS)

An experimental apparatus has been built to measure the flammability limits of combustible gases based on Chinese national standard GB/T 12474-90. The flammability limits of four binary mixtures of R161/R134a, R152a/R134a, R161/N2 and R152a/N2 were measured with this apparatus at atmospheric pressure and ambient temperature. The fuel inertization points (FIP) of these mixtures can be found from the envelopes. Comparisons were made with the literature data; good agreement for most measurements was obtained. R134a was found to have a better dilution effect than nitrogen in reducing the flammability of hydrofluorocarbons.

Li, Zhenming; Gong, Maoqiong; Wu, Jianfeng; Zhou, Yuan

2009-12-01

340

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

341

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

PubMed

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

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

2014-12-16

342

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

343

Near critical phase behaviour of dilute mixtures  

NASA Astrophysics Data System (ADS)

Predictions of the limiting phase behaviour of dilute mixtures of n-decane, n-tetradecane, n-octadecane, and n-docosane with n-hexane in the highly compressible region close to the critical point of n-hexane are presented. The predictions are based on a classical Taylor expansion of the Helmholtz energy about the critical point of the solvent [1, 2] and make use of the measured critical properties of the dilute mixtures. The importance of the Krichevskii parameter as a key factor influencing the limiting phase behaviour of dilute mixtures is demonstrated in the case of infinite dilution partition coefficients as well as solute partial molar volumes, and the link to a statistical mechanical description is made.

Gude, Michael T.; Teja, Amyn S.

344

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

345

Adsorption of nonelectrolytes from dilute aqueous solutions in carbon micropores: a condensation approximation approach  

Microsoft Academic Search

The Dubinin model of micropore volume filling for gas\\/solid adsorption is extended to describe the adsorption of nonelectrolytes from dilute aqueous solutions. Adsorption of poorly soluble organic compounds leads to the complete displacement of water from micropores and to formation of an interface between an adsorbed phase and the solution. The maximum molar work supplied by the field of the

Vladimir Kh. Dobruskin

2000-01-01

346

LLW solidification in cement: Effect of dilution  

SciTech Connect

A simulated Low Level nuclear Waste (LLW) solution was tested for long term solidification in a cement-based matrix. The waste is characterized by high pH and high concentrations of sodium, aluminum, nitrate, nitrite, phosphate and carbonate. The effect of diluting the waste with additional water was studied. The cementitious matrix was composed of cement, fly-ash and clay (21%, 68% and 11% respectively) with high solution to solid ratio (1 liter /1 kg.). Mixes were prepared at 45{degrees}C and cured at 90{degrees}C for 28 days. Maximum 28 day compressive strengths and early age heat evolution were achieved by diluting the LLW solution to approximately 67% of its original concentration. More dilution led to a lower heat evolution and compressive strength. No dilution was found to give lower compressive strength, and a heat evolution that was delayed, and lower in intensity. XRD spectra showed formation of zeolites and tobermorite at the higher concentrations (67, 85, and 100% of the concentration of the undiluted simulated LLW), with a change from Na-Pl zeolite for 67% of the undiluted concentration to a sodalite at 100%. SEM observations showed a porous system for the low and high dilution rates but a less porous one for an intermediate level of dilution.

Kruger, A.A. [Westinghouse Hanford Co., Richland, WA (United States); Katz, A.; Brough, A.R.; Bakharev, T.; Kirkpatrick, R.J.; Struble, L.J.; Young, J.F. [Univ. of Illinois at Urbana-Champaign, IL (United States). Center for Advanced Cement Based Materials

1995-02-01

347

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

E-print Network

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

Wadley, Haydn

348

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

349

Non-invasive assessment of ventilation maldistribution in lung disease using multiple breath inert gas washouts.   

E-print Network

Clinical research in cystic fibrosis (CF) requires study endpoints that are sensitive to airways disease, repeatable and non-invasive. Despite significant advances in the treatment of CF, lung function assessments continue ...

Horsley, Alex

2009-01-01

350

New method speeds body inert gas saturation and utilizes surface decompression  

NASA Technical Reports Server (NTRS)

Method reduces required saturation time from three days to six hours and also reduces required decompression time. Waiting time for planning underwater research is therefore reduced, and emergency surfacing is possible.

Edel, P. O.

1971-01-01

351

A unified numerical modeling of stationary tungsten-inert-gas welding process  

Microsoft Academic Search

In order to clarify the formative mechanism of weld penetration in an arc welding process, the development of a numerical\\u000a model of the process is quite useful for understanding quantitative values of the balances of mass, energy, and force in the\\u000a welding phenomena because there is still lack of experimentally understanding of the quantitative values of them because of\\u000a the

Manabu Tanaka; Hidenori Terasaki; Masao Ushio; John J. Lowke

2002-01-01

352

Optimization of nutrient supply in a downflow gas-phase biofilter packed with an inert carrier  

Microsoft Academic Search

.   Several methodologies were tested to supply nutrients to a downflow biofilter packed with perlite and used to treat toluene-polluted\\u000a air. Despite the presence of an inorganic carrier, elimination capacities of up to around 60 g\\/m3 per hour could be maintained when a basal medium, containing nitrogen, phosphorus and potassium, was supplied once every\\u000a fortnight or even once a month rather

Ó. Prado; J. A. Mendoza; M. C. Veiga; C. Kennes

2002-01-01

353

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

354

Welding of 316L Austenitic Stainless Steel with Activated Tungsten Inert Gas Process  

NASA Astrophysics Data System (ADS)

The use of activating flux in TIG welding process is one of the most notable techniques which are developed recently. This technique, known as A-TIG welding, increases the penetration depth and improves the productivity of the TIG welding. In the present study, four oxide fluxes (SiO2, TiO2, Cr2O3, and CaO) were used to investigate the effect of activating flux on the depth/width ratio and mechanical property of 316L austenitic stainless steel. The effect of coating density of activating flux on the weld pool shape and oxygen content in the weld after the welding process was studied systematically. Experimental results indicated that the maximum depth/width ratio of stainless steel activated TIG weld was obtained when the coating density was 2.6, 1.3, 2, and 7.8 mg/cm2 for SiO2, TiO2, Cr2O3, and CaO, respectively. The certain range of oxygen content dissolved in the weld, led to a significant increase in the penetration capability of TIG welds. TIG welding with active fluxes can increase the delta-ferrite content and improves the mechanical strength of the welded joint.

Ahmadi, E.; Ebrahimi, A. R.

2014-12-01

355

Diffusion coefficients of fluorescent organic molecules in inert gases  

NASA Astrophysics Data System (ADS)

We use arrested-flow pulse broadening to measure the diffusion coefficients of four archetype organic semiconductors in two carrier gases, N2 and Ar, with a precision of 5%. The measurements are realized by the injection and transport of pulses of organic molecules in an organic vapor phase deposition chamber, followed by their detection using laser induced fluorescence that dynamically measures the organic concentration in the gas phase. Measurements show that the diffusivity of tris(8-hydroxyquinoline) aluminum (Alq3) in N2 and Ar varies as the square of the temperature and inversely with pressure over a large range of gas conditions. We show that classical Chapman-Enskog theory can be used to approximate the diffusivity with an accuracy that depends on the physical dimensions of the organic molecular species, with the most accurate predictions for spherical and rigid molecules such as Alq3.

Rolin, Cedric; Forrest, Stephen R.

2013-07-01

356

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

357

Determination of Key Intermediates in Cholesterol and Bile Acid Biosynthesis by Stable Isotope Dilution Mass Spectrometry  

PubMed Central

For more than a decade, we have developed stable isotope dilution mass spectrometry methods to quantify key intermediates in cholesterol and bile acid biosynthesis, mevalonate and oxysterols, respectively. The methods are more sensitive and reproducible than conventional radioisotope (RI), gas-chromatography (GC) or high-performance liquid chromatography (HPLC) methods, so that they are applicable not only to samples from experimental animals but also to small amounts of human specimens. In this paper, we review the development of stable isotope dilution mass spectrometry for quantifying mevalonate and oxysterols in biological materials, and demonstrate the usefulness of this technique. PMID:19609389

Yoshida, Tadashi; Honda, Akira; Miyazaki, Hiroshi; Matsuzaki, Yasushi

2008-01-01

358

Dilute nitride InNP quantum dots: Growth and photoluminescence mechanism  

NASA Astrophysics Data System (ADS)

Self-assembled dilute nitride InNP quantum dots (QDs) in GaP matrix grown under the Stranski-Krastanov mode by gas-source molecular beam epitaxy are studied. The N-related localized states inside the InNP QDs provide a spatially direct recombination channel, in contrast to the spatially indirect channel through the strained In(N)P QDs/GaP interface states. The N incorporation into InP QDs therefore causes a blueshift and double-peak features in photoluminescence, which are not observed in other dilute nitride materials.

Kuang, Y. J.; Takabayashi, K.; Sukrittanon, S.; Pan, J. L.; Kamiya, I.; Tu, C. W.

2014-10-01

359

Dissolved gas concentrations of the geothermal fluids in Taiwan  

NASA Astrophysics Data System (ADS)

Taiwan, a geologically active island, is located on the boundary of the Philippine Sea Plate and the Eurasian Plate. High heat flow and geothermal gradient generated by the complex collision and orogeny, warm up the meteoric water and/or the ground water. The heated water becomes geothermal fluids. In previous studies, researchers tried to categorize hot springs based on the appearance, chemical compositions and lithological areas. Because of the chemical inertness, the concentrations and isotopic composition of dissolved noble gases are good indicators of the mantle degassing, geothermal conditions, and so on. In this study, 55 hot springs were collected from different tectonic units. It is the first time to systematically study the hot springs in Taiwan in terms of dissolved gases. Hot spring water is sampled and stored in pre-evacuated glass bottles for analyzing gas compositions. The abundances of noble gases were determined by a quadrupole mass spectrometer based on the isotope dilution technique. Samples with glass vials are introduced to RAD 7 and GC for dissolved Rn and major dissolved gases analyses. Furthermore, helium isotopic ratios and helium-neon ratios are measured on a conventional noble gas mass spectrometer. For hydrochemistry analysis, water samples are analyzed by IC, ICP-MS and titration. We can classify the hot springs samples into three major groups from main anion concentration data; and then, subdivide them into nine minor groups by cation concentration data. Moreover, according to major dissolved gases compositions, three major gas components: CH4, N2 and CO2, are identified. Dissolved noble gases provided more detailed clues about hot springs sources in Taiwan, such as the degree of mixing between meteoric water and deep-source water, which will be further discussed in this study.

Chen, Ai-Ti; Yang, Tsanyao Frank

2010-05-01

360

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

361

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

362

Mossbauer effect in dilute iron alloys  

NASA Technical Reports Server (NTRS)

The effects of variable concentration, x, of Aluminum, Germanium, and Lanthanum atoms in Iron lattice on various Mossbauer parameters was studied. Dilute binary alloys of (Fe-Al), (Fe-Ge), (Fe-Al) containing up to x = 2 a/o of the dilute constituent were prepared in the form of ingots and rolled to a thickness of 0.001 in. Mossbauer spectra of these targets were then studied in transmission geometry to measure changes in the hyperfine field, peak widths isomer shifts as well as the ratio of the intensities of peaks (1,6) to the intensities of peaks (2,5). It was shown that the concept of effective hyperfine structure field in very dilute alloys provides a useful means of studying the effects of progressively increasing the solute concentration on host lattice properties.

Singh, J. J.

1975-01-01

363

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

364

Three Extra Mirror or Sequential Families: Case for a Heavy Higgs Boson and Inert Doublet  

SciTech Connect

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{sub Z}.

Martinez, Homero [CEA, Saclay, DSM-IRFU-SPP (France); Melfo, Alejandra [ICTP, Trieste (Italy); Universidad de Los Andes, Merida (Venezuela, Bolivarian Republic of); Nesti, Fabrizio [Universita di Ferrara, Ferrara (Italy); Senjanovic, Goran [ICTP, Trieste (Italy)

2011-05-13

365

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

366

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

367

One-dimensional model for water and aqueous solutions. II. Solvation of inert solutes in water  

NASA Astrophysics Data System (ADS)

The two one-dimensional models introduced in Part I are used to study the thermodynamics of solvation of inert solutes in water. It is shown that the anomalously large Gibbs energy of solvation of inert solutes in water, on one hand, and the large negative entropy of solvation, on the other hand, arise from different molecular sources. While the primitive model can give rise to a large positive solvation Gibbs energy, it fails to show large negative entropy and enthalpy of solvation. It is remarkable that the primitive cluster model can show both the large positive Gibbs energy and enthalpy of solvation.

Ben-Naim, Arieh

2008-01-01

368

The "dilution effect" in stallion sperm.  

PubMed

Dilution of semen to less than 20 × 10(6) sperm/mL has been reported to decrease sperm quality in multiple species, a phenomenon known as the semen "dilution effect." Critical evaluation of stallion semen diluted to these concentrations, however, has not been reported. This study evaluated sperm motion characteristics (percent total motility [TMOT], percent progressive motility [PMOT], curvilinear velocity [?m/s], and percent straightness) and plasma membrane integrity (percent plasma membrane intact [PMI]) in semen samples diluted to 2.5 × 10(6) sperm/mL with the addition of 0%, 7.5%, or 25% seminal plasma (groups T-2.5/0, T-2.5/7.5, and T-2.5/25, respectively), or after simple dilution to 30 × 10(6) sperm/mL (group T-30), or simple dilution to a ratio of 3:1 (extender:semen; group T-3:1SD). Evaluations were performed immediately after semen collection (T0), and after 24 and 48 hours of cooled storage (T24 and T48, respectively). The PMI and TMOT were the highest in group T-3:1SD at T0. At T24, the PMI in groups T-30, T3:1SD and T3:1/30, and T-2.5/0 were higher than that in the other groups (P < 0.05), whereas TMOT in group T-3:1SD was higher (P < 0.05) than that in all other groups except T-30. By T48, no difference was detected for PMI among groups T-3:1SD, T-30, and T-2.5/0; for TMOT among groups T-3:1SD, T-30, and T-2.5/0, and T-2.5/7.5 (P > 0.05), whereas PMOT was the highest in groups T-2.5/0 and T-2.5/7.5 (P < 0.05). These findings revealed that treatments in which semen was diluted to a concentration of 2.5 × 10(6) sperm/mL had lower initial PMI, TMOT, and PMOT, but semen quality did not decline after 24 and 48 hours of cooled storage. In this study, TMOT and PMI in dilute semen were less than those in more concentrated semen at T0. This effect, while significant, was small and less apparent after cooled storage. PMID:25543156

Hayden, Shelby S; Blanchard, Terry L; Brinsko, Steven P; Varner, Dickson D; Hinrichs, Katrin; Love, Charles C

2015-03-01

369

Gas electron multiplier (GEM) enhanced ionization chamber for fluorescence detector  

Microsoft Academic Search

Detecting dilute elements in thin materials using extended X-ray absorption fluorescence spectroscopy (EXAFS) method requires a detector capable of high count rate and low noise. For detection of dilute elements, the fluorescence signal amplitude is often overcome by the presence of noise or background interference. In this paper we have used a gas ionization chamber enhanced by a gas electron

E. H. Shaban; D. P. Siddons; A. Kuczewski

2007-01-01

370

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

NASA Astrophysics Data System (ADS)

The influence of inert gas ionisation on the expansion dynamics of a laser ablation plume propagating through an inert gas is studied. Charge transfer reactions between ionised ablated species and gas neutrals lead to the formation of a charged layer of ionised gas atoms in contact with the plume expansion front. The energy lost by fast ablated ions when the plume is slowed down is calculated. For the exemplary carbon ablation in helium and argon atmospheres, where background gas ionisation plays a different role, model predictions agree with the observed microstructural differences of deposited films.

Bailini, A.; Ossi, P. M.

2005-10-01

371

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

372

Automatic dilution gaging of rapidly varying flow  

USGS Publications Warehouse

Obtaining discharge ratings at urban gaging stations is often difficult. Results of using an automated constant-rate dye-dilution technique to measure discharge at two sites in Madison, Wisconsin, are presented. The sites selected have well-defined stage-discharge ratings, developed during previous hydrologic studies. One site is a 60-inch-diameter concrete storm sewer and the other a concrete-lined open trapezoidal channel. Equipment selected to automate the method included a portable automatic water sampler, four-channel event recorder; and for dye injection, a peristaltic pump. An electrical switching circuit was designed to coordinate the operation of the water sampler, injection pump, and four-channel recorder. During the data-collection period of 1 year, a total of 20 storms was monitored. The analyses showed that the discharges measured by dye-dilution techniques ranged from + or - 5 to + or - 10 percent of the discharges determined from ratings established by current-meter measurements. Larger differences were noted at the start of and on the rising limb of four hydrographs. Of the 20 storms monitored, 17 produced acceptable results. Peak discharges by the dilution method at the open-channel site ranged from 0 to 12 percent departures from the existing rating, whereas the peak discharge by the dilution method at the storm-sewer site ranged from 0 to 5 percent departures from the existing rating. (UGGS)

Duerk, M.D.

1983-01-01

373

THE MOST DILUTE LAKE IN THE WORLD?  

EPA Science Inventory

Lake Notasha, near the crest of the Oregon Cascade mountain range, is the most dilute lake known. he measured conductivity during two visits was 1.3 and 1.6 uS cm-1, with a sum of base cations of 9 and 18 ueq L-1; bicarbonate was the dominant anion. ost of the cations in the lake...

374

Dissipative stresses in dilute polymer solutions  

Microsoft Academic Search

Planar extensional flows of a dilute polymer solution are investigated using a free-draining bead-rod model. For steady flows, an analytic expression for the probability density of the polymer configuration is available. It is found that part of the associated steady polymer stress is unambiguously viscous at all time scales, in the sense that on cessation of flow it disappears instantaneously,

J. M. Rallison

1997-01-01

375

Science Sampler: Dilution, Concentration, and Flotation  

NSDL National Science Digital Library

Classroom teaching practice and literature show that many students have difficulties with science concepts such as density. These investigations identify the relationship between density and floating through experimenting with successive dilution of a liquid, or the systematic change of concentration of a saltwater solution. The lessons follow the constructivist teaching model--invitation, exploration, proposing explanations, and taking action.

Joseph S. Schmuckler

2004-04-01

376

AN INITIAL DILUTION ZONE IMPACT ASSESSMENT  

E-print Network

TECHNICAL REPORT SERIES FREMP WQWM 93-06 DOE FRAP 1993-14 Prepared for FREMP Water Quality/Waste Management estuary (Technical report serices; WQWM 93-06) (Technical report series; DOE FRAP 1993-14) Includes FRAP 1993-14. TD227.F7N67 1993 363.73'942'0971133 C93-960027-X #12;INITIAL DILUTION ZONE IMPACT

377

Zinc oxide based diluted magnetic semiconductors  

Microsoft Academic Search

During my graduate research I have synthesized materials known as diluted magnetic semiconductors (DMS) as epitaxial thin film structures using the process of pulsed laser deposition (PLD). These materials are envisioned to be of importance in the emerging field of spintronics where the charge as well as the spin of the charge carriers can be combined to yield unique functionalities

Shivaraman Ramachandran

2007-01-01

378

Sulfuric Acid and Water: Paradoxes of Dilution  

ERIC Educational Resources Information Center

On equilibrium properties of aqueous solutions of sulfuric acid, Julius Thomsen has marked that the heat evolved on diluting liquid sulfuric acid with water is a continuous function of the water used, and excluded absolutely the acceptance of definite hydrates as existing in the solution. Information about thermochemical measurement, a discussion…

Leenson, I. A.

2004-01-01

379

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....

380

Quasi-static vapor pressure measurements on reactive systems in inert atmosphere box  

NASA Technical Reports Server (NTRS)

Apparatus makes vapor pressure measurements on air-sensitive systems in an inert atmosphere glove box. Once the apparatus is loaded with the sample and all connections made, all measuring operations may be performed outside the box. The apparatus is a single-tube adaptation of the double-tube quasi-static technique.

Fischer, A. K.

1968-01-01

381

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

382

Inert doublet dark matter with an additional scalar singlet and 125 GeV Higgs boson  

NASA Astrophysics Data System (ADS)

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 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 and . We treat one of these scalars, , to be consistent with the SM Higgs-like boson of mass around 125 GeV reported by the LHC experiment. These two CP even scalars contribute to 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 and processes and compared these with LHC results. This is also used to constrain the dark matter parameter space in the present model. We find that the dark matter candidate in the mass region 60-80 GeV ( GeV, mass of ) satisfies the recent bound from LUX direct detection experiment.

Dutta Banik, Amit; Majumdar, Debasish

2014-11-01

383

Method of enhanced lithiation of doped silicon carbide via high temperature annealing in an inert atmosphere  

SciTech Connect

A method for enhancing the lithium-ion capacity of a doped silicon carbide is disclosed. The method utilizes heat treating the silicon carbide in an inert atmosphere. Also disclosed are anodes for lithium-ion batteries prepared by the method.

Hersam, Mark C.; Lipson, Albert L.; Bandyopadhyay, Sudeshna; Karmel, Hunter J; Bedzyk, Michael J

2014-05-27

384

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

385

Field measurements of particle dry deposition rates to foliage and inert surfaces in a forest canopy  

Microsoft Academic Search

The authors measured dry deposition rates of particulate SOâ\\/sup 2 -\\/, NOâ⁻, Ca\\/sup 2 +\\/, and K\\/sup +\\/ to leaves and inert surfaces in the upper canopy of a deciduous forest at Walker Branch Watershed, TN. During 8 dry periods of several days duration each, polycarbonate Petri dishes were exposed adjacent to growing leaves in a chestnut oak tree at

Steven E. Lindberg; Gary M. Lovett

1985-01-01

386

OPTIMIZATION OF INERT DUSTS USED AS GRAIN PROTECTANTS AND RESIDUAL SURFACE TREATMENTS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Inert dusts such as diatomaceous earth (DE) are being advocated as natural control methods to eliminate insect infestations in stored grain, milling and processing plants, and food storage areas. However, efficacy of DE can be quite variable, depending on the specific formulation of DE, the particul...

387

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, Renée

2009-01-01

388

Conditional statistics of inert droplet effects on turbulent combustion in reacting mixing layers  

Microsoft Academic Search

Direct numerical simulation (DNS) of turbulent reacting mixing layers laden with evaporating inert droplets is used to assess the droplet effects in the context of the conditional moment closure (CMC) for multiphase turbulent combustion. The temporally developing mixing layer has an initial Reynolds number of 1000 based on the vorticity thickness with more than 16 million Lagrangian droplets traced. An

J. Xia; K. H. Luo

2009-01-01

389

Does the Addition of Inert Gases at Constant Volume and Temperature Affect Chemical Equilibrium?  

ERIC Educational Resources Information Center

In this article we examine three approaches, leading to different conclusions, for answering the question "Does the addition of inert gases at constant volume and temperature modify the state of equilibrium?" In the first approach, the answer is yes as a result of a common students' alternative conception; the second approach, valid only for ideal…

Paiva, Joao C. M.; Goncalves, Jorge; Fonseca, Susana

2008-01-01

390

USE OF AN INERT RADIOACTIVE PARTICLE FOR MEASURING PARTICLE ACCUMULATION BY FILTER-FEEDING BIVALVE MOLLUSCS  

EPA Science Inventory

The use of an inert, radioactively labeled microsphere as a measure of particle accumulation (filtration activity) by Mulinia lateralis (Say) and Mytilus edulis L. was evaluated. Bottom sediment plus temperature and salinity of the water were varied to induce changes in filtratio...

391

PAPER www.rsc.org/loc | Lab on a Chip Teflon films for chemically-inert microfluidic valves and pumps  

E-print Network

PAPER www.rsc.org/loc | Lab on a Chip Teflon films for chemically-inert microfluidic valves800600h We present a simple method for fabricating chemically-inert Teflon microfluidic valves and pumps for microfluidic devices. Previous work has shown that spin-coated amorphous fluoropolymers and Teflon

Manalis, Scott

392

Optimizing the effective conductivity and cost of gas-filled panel thermal insulations  

Microsoft Academic Search

Gas-Filled Panels, or GFPs, are an advanced thermal insulation that employ a low-conductivity, inert gas, at atmospheric pressure, within a multilayer reflective baffle. The thermal performance of GFPs varies with gas conductivity, overall panel thickness, and baffle construction. Design parameters of baffle constructions that have a strong effect on GFP thermal resistance are (1) cavities per thickness, (2) cavity surface

B. Griffith; D. Tuerler; D. Arasteh

1993-01-01

393

Microstructural Characterization of a Polycrystalline Nickel-Based Superalloy Processed via Tungsten-Intert-Gas-Shaped Metal Deposition  

Microsoft Academic Search

Recent trials have produced tungsten-inert-gas (TIG)-welded structures of a suitable scale to allow an evaluation of the technique as an economic and commercial process for the manufacture of complex aeroengine components. The employment of TIG welding is shown to have specific advantages over alternative techniques based on metal inert gas (MIG) systems. Investigations using the nickel-based superalloy 718 have shown

Daniel Clark; Martin R. Bache; Mark T. Whittaker

2010-01-01

394

Microstructural Characterization of a Polycrystalline Nickel-Based Superalloy Processed via Tungsten-Intert-Gas-Shaped Metal Deposition  

Microsoft Academic Search

Recent trials have produced tungsten-inert-gas (TIG)-welded structures of a suitable scale to allow an evaluation of the technique\\u000a as an economic and commercial process for the manufacture of complex aeroengine components. The employment of TIG welding\\u000a is shown to have specific advantages over alternative techniques based on metal inert gas (MIG) systems. Investigations using\\u000a the nickel-based superalloy 718 have shown

Daniel Clark; Martin R. Bache; Mark T. Whittaker

2010-01-01

395

40 CFR 1065.667 - Dilution air background emission correction.  

Code of Federal Regulations, 2011 CFR

... 2011-07-01 false Dilution air background emission correction...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES...Requirements § 1065.667 Dilution air background emission...

2011-07-01

396

40 CFR 1065.667 - Dilution air background emission correction.  

Code of Federal Regulations, 2013 CFR

... 2013-07-01 false Dilution air background emission correction...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES...Requirements § 1065.667 Dilution air background emission...

2013-07-01

397

40 CFR 1065.667 - Dilution air background emission correction.  

Code of Federal Regulations, 2010 CFR

... 2010-07-01 false Dilution air background emission correction...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES...Requirements § 1065.667 Dilution air background emission...

2010-07-01

398

40 CFR 1065.667 - Dilution air background emission correction.  

Code of Federal Regulations, 2012 CFR

... 2012-07-01 false Dilution air background emission correction...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES...Requirements § 1065.667 Dilution air background emission...

2012-07-01

399

40 CFR 1066.610 - Dilution air background correction.  

... 2014-07-01 false Dilution air background correction. 1066.610...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS VEHICLE-TESTING PROCEDURES...Calculations § 1066.610 Dilution air background correction....

2014-07-01

400

40 CFR 1065.667 - Dilution air background emission correction.  

... 2014-07-01 false Dilution air background emission correction...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES...Requirements § 1065.667 Dilution air background emission...

2014-07-01

401

Helium 3/Helium 4 dilution cryocooler for space  

NASA Technical Reports Server (NTRS)

Prototype dilution cryocoolers based on dilution refrigeration and adiabatic demagnetization refrigeration (ADR) cycles were designed, constructed, and tested. Although devices the devices did not operate as fully functional dilution cryocoolers, important information was gathered. The porous metal phase separator was demonstrated to operate in the -1-g configuration; this phase separation is the critical element in the He-3 circulation dilution cryocooler. Improvements in instrumentation needed for additional tests and development were identified.

Hendricks, John B.; Dingus, Michael L.

1991-01-01

402

Dilution jet mixing program, supplementary report  

NASA Technical Reports Server (NTRS)

The velocity and temperature distributions predicted by a 3-D numerical model and experimental measurements are compared. Empirical correlations for the jet velocity trajectory developed are presented. The measured velocity distributions for all test cases of phase through phase 3 are presented in the form of contour and oblique plots. quantification of the effects of the following on the jet mixing characteristics with a confined crossflow are: (1) orifice geometry momentum flux ratio and density ratio; (2) nonuniform mainstream temperature and velocity profiles upstream of dilution orifices; (3) cold versus hot jet injection; (4) cross-stream flow are a convergence as encountered in practical dilution zone geometries; (5) 2-D slot versus circular orifices; (6) discrete noncirculcer orifices; (7) single-sided versus opposed jets; (8) single row of jets.

Srinivasan, R.; White, C.

1986-01-01

403

Spectroscopic imaging of a dilute cell suspension  

E-print Network

A rigorous homogenization theory is derived to describe the effective admittivity of cell suspensions. A new formula is reported for dilute cases that gives the frequency-dependent effective admittivity with respect to the membrane polarization. Different microstructures are shown to be distinguishable via spectroscopic measurements of the overall admittivity using the spectral properties of the membrane polarization. The Debye relaxation times associated with the membrane polarization tensor are shown to be able to give the microscopic structure of the medium. A natural measure of the admittivity anisotropy is introduced and its dependence on the frequency of applied current is derived. A Maxwell-Wagner-Fricke formula is given for concentric circular cells, and the results can be extended to the random cases. A randomly deformed periodic medium is also considered and a new formula is derived for the overall admittivity of a dilute suspension of randomly deformed cells.

Habib Ammari; Josselin Garnier; Laure Giovangigli; Wenjia Jing; Jin-Keun Seo

2013-10-04

404

The Pliocene Yafo Formation in Israel: Hydrogeologically inert or active?  

NASA Astrophysics Data System (ADS)

For several decades the ``Saqiye beds'' (later renamed Yafo Formation) underlying the Coastal Plain aquifer (Kurkar Group) aquifer of Israel, were regarded as an extremely thick, tectonically undisturbed, and absolutely impervious aquiclude. Following intensive groundwater exploitation from the overlying Kurkar Group aquifer, brackish and saline waters were locally encountered in the lower parts of this aquifer and always at the contact with the underlying Yafo Formation aquiclude. The present study revealed that this aquiclude is not a uniform and impervious rock unit, but rather an alternation of pervious and impervious strata within the Yafo Formation containing highly pressured fluids of different - mostly high - salinities. The permeable beds are at an angular unconformity and in direct contact with the overlying Kurkar Group aquifer. The Yafo Formation and the underlying and overlying rock units are dislocated by numerous fault systems, which facilitate accessibility of brines into the Kurkar Group aquifer. The mobilization of the saline fluids and their injection into the Kurkar Group aquifer could be due either to diffusion of saline fluids occurring in the permeable horizons of the Petah Tiqva Member through the clays of the Yafo Formation or to their upconing following intensive pumping in the Coastal Plain aquifer. It could have also been caused by up-dip movement of saline water as the result of overpressure generated by major accumulation of gas in the permeable horizons. Another possible mechanism could be hydraulic contact with pressurized brines up-flowing along fault zones from deep-seated Jurassic or Cretaceous reservoirs. The squeezing of saline interstitial water from the clays of the Yafo Formation into the overlying Kurkar Group aquifer, is of secondary importance for groundwater salinization (its input is comparable with salt input from rain). Depuis longtemps, les «couches de Saqiye», nommées maintenant formation de Yafo, constituant le mur de l'aquifère côtier (série de Kurkar) d'Israël, ont été considérées comme un ensemble extrêmement épais, sans déformation tectonique et totalement imperméable. À la suite de l'exploitation intensive de l'eau souterraine de l'aquifère sus-jacent de la série de Kurkar, des eaux salées et des saumures sont rencontrées occasionnellement dans les parties les plus profondes de cet aquifère et toujours au contact de l'imperméable sous-jacent de la formation de Yafo. Cette étude a révélé que cet imperméable n'est pas une unité géologique uniforme et imperméable, mais qu'il s'agit plutôt d'une alternance de couches perméables et imperméables dans la formation de Yafo contenant des fluides sous des pressions fortes avec des salinités différentes (?) et en général élevées (?). Les niveaux perméables sont en discordance angulaire et en contact direct avec l'aquifère sus-jacent de la série de Kurkar. La formation de Yafo et les unités géologiques situées dessous et dessus sont disloquées par de nombreuses systèmes de failles, qui facilitent le passage des saumures dans l'aquifère de la série de Kurkar. La mobilisation des fluides salins et leur injection dans l'aquifère de Kurkar pourraient être dues soit à la diffusion des fluides salins dans les horizons perméables du Petah Tiqva au travers des argiles de la formation de Yafo, soit leur remontée par upconing sous l'effet de pompages intensifs dans l'aquifère de la plaine côtière. Il peut aussi être causé par la remontée des eaux salines selon le pendage sous l'effet d'une surpression provoquée par une accumulation considérable de gaz dans les horizons imperméables. Un autre mécanisme possible pourrait être un contact hydraulique avec des saumures sous pression, remontant le long des zones de faille depuis des réservoirs profonds jurassiques ou crétacés. L'expulsion d'eau saline interstitielle des argiles de la formation de Yafo dans l'aquifère de Kurkar est d'importance secondaire pour la salinisation de l'eau souterraine cet apport est comparable à ce

Avisar, D.; Rosenthal, E.; Shulman, H.; Zilberbrand, M.; Flexer, A.; Kronfeld, J.; Ben Avraham, Z.; Fleischer, L.

405

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

406

Employee stock options, EPS dilution, and stock repurchases  

Microsoft Academic Search

We investigate whether corporate executives’ stock repurchase decisions are affected by their incentives to manage diluted earning per share (EPS). We find that executives increase the level of their firms’ stock repurchases when: (1) the dilutive effect of outstanding employee stock options (ESOs) on diluted EPS increases, and (2) earnings are below the level required to achieve the desired rate

Daniel A. Bens; Venky Nagar; Douglas J. Skinner; M. H. Franco Wong

2003-01-01

407

Interaction of clays with dilute fluoride solutions  

Microsoft Academic Search

Interaction between dilute (mg L-1) NaF solutions and clay suspensions (0.08 % w\\/v) has been examined as a function of pH (range 3 to 8), clay type (Na+- or Ca2+-kaolinite, illite, montmorillonite) and NaF concentration. No F loss from solution was detected at pH > 6.5, while enhanced uptake was found on decreasing the pH, especially in the 4 to

J. Slavek; H. Farrah; W. F. Pickering

1984-01-01

408

Spectra of turbulence in dilute polymer solutions  

E-print Network

We investigate turbulence in dilute polymer solutions when polymers are strongly stretched by the flow. We establish power-law spectrum of velocity, which is not associated with a flux of a conserved quantity, in two cases. The first case is the elastic waves range of high Reynolds number turbulence of polymer solutions above the coil-stretch transition. The second case is the elastic turbulence, where chaotic flow is excited due to elastic instabilities at small Reynolds numbers.

A. Fouxon; V. Lebedev

2002-07-02

409

Zinc oxide-based diluted magnetic semiconductors  

Microsoft Academic Search

The current experimental situation on the occurrence or absence of ferromagnetism in diluted magnetic semiconductors based on wurtzite zinc oxide hosts is presented, focusing mainly on the many recent experiments which have been performed on bulk systems. Numerous reports have suggested that partial (typically less than 10at.%) substitution of Zn2+ in ZnO by magnetic transition metal (tM) ions, particularly Mn2+

Ram Seshadri

2005-01-01

410

Kinetic theory for dilute dipolar systems  

NASA Astrophysics Data System (ADS)

We propose a new kinetic theory to study dilute dipolar systems and apply it to the calculation of the angular velocity autocorrelation function for a system of Stockmayer molecules (Lennard-Jones particles with point dipoles) in the supercritical region. The predictions made from the theory are in excellent agreement with results obtained from molecular dynamics simulations over a broad range of densities above the critical temperature. The theory can be generalized to describe dielectric relaxation in supercritical water.

Bembenek, Scott D.; Szamel, Grzegorz

2002-11-01

411

Condensation stage of a pulse tube pre-cooled dilution refrigerator  

Microsoft Academic Search

In our article, experiments with a pulse tube (PTR) pre-cooled dilution refrigerator (DR) are presented, where an upgraded 3He condensation stage has been tested. The DR had a 3He flow rate of up to 1.1mmol\\/s. The 3He gas entering the refrigerator was first pre-cooled to a temperature of ?50K at the first stage of the PTR. In the next cooling

Kurt Uhlig

2008-01-01

412

Effect of topography on deposition from dilute pyroclastic density currents simulated by Ansys Fluent software  

Microsoft Academic Search

Pyroclastic density currents are volcanic gas-particle flows that move along volcano flanks and over the neighboring topography. Flow particle concentration can vary between two end members, concentrated and dilute. When a pyroclastic density current interacts with an uneven topography, the flow-field variables (velocity, pressure, particle concentration) are drastically changed at the flow-substrate boundary. These changes may significantly affect the sedimentation

Domenico Maria Doronzo; Greg A. Valentine; Pierfrancesco Dellino; Marco D. de Tullio

2010-01-01

413

Ignition of steel alloys by impact of low-velocity iron/inert particles in gaseous oxygen  

NASA Technical Reports Server (NTRS)

The ignition of carbon steel and 316 and 304 stainless steels caused by the impact of low-velocity particles (a standard mixture consisting of 2 g of iron and 3 g of inert materials) in gaseous oxygen was investigated using NASA/White Sands Test Facility for the ignition test, and a subsonic particle impact chamber to accelerate the particles that were injected into flowing oxygen upstream of the target specimen. It was found that the oxygen velocities required to ignite the three alloys were the same as that required to ignite the particle mixture. Ignition occurred at oxygen velocities greater than 45 m/sec at 20 to 24 MPa and was found to be independent of pressure between 2 and 30 MPa. Comparison of the present results and the past results from Wegener (1964) with the Compressed Gas Association (CGA) oxygen velocity limits for safe operations indicates that the CGA limits may be excessively conservative at high pressures and too liberal at low pressures.

Benz, Frank J.; Mcilroy, Kenneth; Williams, Ralph E.

1988-01-01

414

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

415

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

416

Conductometric studies of the serially diluted and agitated solutions on an anomalous effect that depends on the dilution process  

Microsoft Academic Search

We analysed the experimental data related to the specific conductivities of several serially diluted and agitated solutions (SDA for short). The experimental procedure consisted in measuring the specific conductivity, ? (?S cm?1), of samples of SDA we prepared several months before. After characterizing the SDA, we diluted them with twice distilled water at several ratio of dilution, ranging from 1:1

V. Elia; L. Elia; M. Montanino; E. Napoli; M. Niccoli; L. Nonatelli

2007-01-01

417

A Comparison of the Properties of Diluted Bitumen Crudes with other Oils A Comparison of the Properties of Diluted Bitumen  

E-print Network

A Comparison of the Properties of Diluted Bitumen Crudes with other Oils A Comparison of the Properties of Diluted Bitumen Crudes with other Oils POLARIS Applied Sciences, Inc. (2013) Abstract Diluted bitumen (dilbit) crude oil represents a range of oils produced from bitumen extracted from oil sands

New Hampshire, University of

418

Lanthanide(III) Complexes with a Reinforced Cyclam Ligand Show Unprecedented Kinetic Inertness.  

PubMed

Lanthanide(III) complexes of a cross-bridged cyclam derivative containing two picolinate pendant arms are kinetically inert in very harsh conditions such as 2 M HCl, with no dissociation being observed for at least 5 months. Importantly, the [Ln(dota)](-) complexes, which are recognized to be extremely inert, dissociate under these conditions with lifetimes in the range ca. 1 min to 12 h depending upon the Ln(3+) ion. X-ray diffraction studies reveal octadentate binding of the ligand to the metal ion in the [Eu(cb-tedpa)](+) complex, while (1)H and (13)C NMR experiments in D2O point to the presence of a single diastereoisomer in solution with a very rigid structure. The structure of the complexes in the solid state is retained in solution, as demonstrated by the analysis of the Yb(3+)-induced paramagnetic shifts. PMID:25495928

Rodríguez-Rodríguez, Aurora; Esteban-Gómez, David; Tripier, Raphaël; Tircsó, Gyula; Garda, Zoltán; Tóth, Imre; de Blas, Andrés; Rodríguez-Blas, Teresa; Platas-Iglesias, Carlos

2014-12-31

419

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-solutions are presented and discussed.

Mendelsohn, M.H.; Livengood, C.D. [Argonne National Lab., IL (United States)

1996-12-31

420

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

421

Method of making composition suitable for use as inert electrode having good electrical conductivity and mechanical properties  

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 metals or 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. 8 figs.

Ray, S.P.; Rapp, R.A.

1986-04-22

422

Method of making composition suitable for use as inert electrode having good electrical conductivity and mechanical properties  

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 metals or 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.

Ray, Siba P. (Pittsburgh, PA); Rapp, Robert A. (Columbus, OH)

1986-01-01

423

The development of an inert simulant for HNS/teflon explosive  

NASA Technical Reports Server (NTRS)

The report describes the development and evaluation of an inert simulant for the thermally stable, heat-resistant plastic-bonded explosive HNS/Teflon. The simulant is made by dry blending vinylidene fluoride, melamine and Teflon which when compared has a pressed density and thermal properties corresponding closely to the explosive. In addition, the machinability and handling characteristics of the simulant are similar to the explosive.

Elban, W. L.

1972-01-01

424

Synthesis and characterization of hydroxylapatite-inert ceramic composites and their coatings on biometals  

Microsoft Academic Search

In the first part of this thesis, HAP composites with nearly inert crystalline ceramics (alumina or zirconia) were synthesized to improve their mechanical properties and phase stability. In the second part, these composites were coated on Co-Cr-Mo and Ti-6Al-4V by cold pressing. The best combination of the composites and the metals were identified. In HAP-alpha-n-Al2O3 composites, HAP decomposed to tri-calcium-phosphate

Zafer Evis

2003-01-01

425

A novel solid-state fermentation system using polyurethane foam as inert carrier  

Microsoft Academic Search

A novel solid-state fermentation method using polyurethane foam as inert carrier impregnated with a synthetic liquid medium was developed simulating the nutritional composition and culture conditions of solid-state fermentation on wheat bran. With this system, biomass, the important parameter involved in solid-state fermentation processes, can be measured directly. Some other superiorities of this system over conventional solid-state fermentation systems are

Y. Zhu; J. P. Smits; W. Knol; J. Bol

1994-01-01

426

Effect of milk replacer and rumen inert fat on growth and reproduction of Malpura ram lambs.  

PubMed

The objective of this study was to assess the effects of milk replacer and rumen inert fat on growth, testicular development, puberty, semen production and sperm motion characteristics of ram lambs reared under intensive management in semi-arid climatic conditions. Seven-day-old male lambs of Malpura breed (n=20) were divided equally into two groups. Up to weaning, the lambs in G1 group (control) were fed concentrate, green khejri (Prosopis cineraria) leaves and cowpea (Vigna unguiculata) hay along with suckling of dams, whereas lambs in G2 group were fed reconstituted milk at 17 g/lamb per day for the 1st week and at 34 g/lamb per day from 2nd week in addition to the feed inputs given in G1. During post weaning, lambs in the G1 group were given control concentrate, whereas in G2 the control concentrate supplemented with 40 g rumen inert fat per kg of feed was offered along with dry pala (Zizyphus nummularia) and ardu (Ailanthus excelsa) leaves. BWs of lambs were recorded weekly up to 6 months of age. Ram lambs of both the groups were trained for semen collection at a weekly interval from the age of 5 months and simultaneously testicular measurements were recorded fortnightly. The feeding of milk replacer and rumen inert fat had positive (P<0.05) effects on BW, testicular length, testicular volume, semen volume, sperm concentration, mass motility, % motility, % rapid, medium or slow motile spermatozoa. However, no significant effect was observed on testicular breadth, scrotal circumference, age of puberty, sperm velocities and other CASA-derived parameters. The results of this study indicate that higher plane of nutrition in the form of milk-replacer feeding during preweaning and rumen inert fat-supplemented feed during the postweaning period to growing ram lambs enhances their growth, testicular development and semen quality. PMID:24524327

Kumar, D; Bhatt, R S; Karim, S A; Naqvi, S M K

2014-04-01

427

Brownian motion of inert tracer macromolecules in polymerized and spontaneously bundled mixtures of actin and filamin  

Microsoft Academic Search

Abstract. By use of light microscopy,and fluorescence photobleaching recovery, we have studied (a) struc- tures that form in a system composed,of copolymer- ized rabbit muscle,actin and chicken,gizzard filamin and (b) the Brownian motion,of inert tracer macromol- eeules in this matrix. We have used as tracers size- fractionated fluorescein-labeled ficoll and submicron polystyrene latex particles. In F-actin solutions, the relative diffusion

Li Hou; Katherine Luby-phelps; Frederick Lanni

1990-01-01

428

TOPICAL REVIEW: Inertial rotation and matrix interaction effects on the EPR spectra of methyl radicals isolated in 'inert' cryogenic matrices  

NASA Astrophysics Data System (ADS)

The CW-EPR lineshapes of methyl and small methyl-like radicals trapped in noble gas matrices at liquid He temperatures are substantially different from the expected classical EPR spectra. At low temperatures they show small or negligible anisotropy in studies using different experimental techniques and have a temperature dependence that differs from systems whose motional dynamics is diffusion controlled. At liquid He temperatures, before the Boltzmann statistics take over in the classical high temperature realm, the spectral intensities are dominated by quantum statistics. These properties, which were obtained experimentally at temperatures about 5 K and lower, and up to about 20 K, can be attributed to quantum effects of inertial rotary motion and its coupling to the nuclear spin of the radical. Methyl-like radicals have nuclear-exchange symmetry and contain the lightest possible isotopes, protons, and deuterons. In the ideal case of absent radical-matrix interaction, the methyl rotation about the central heavier carbon atom guaranties minimal moments of inertia. However, the theoretical interpretation of the above effects and other related quantum effects, as well as recognition of the important physics which lead to them, is not a simple matter. The literature accumulated on the subject over the years is successful but contains several unresolved questions. Recently obtained spectra of methyl radicals in Kr, N2 and CO matrices, which are less inert than the smaller noble gas Ar, were shown to exhibit greater, but certainly slight, overall anisotropic spectral features while in earlier experimental studies the anisotropy was practically absent. Even gases of smaller radii such as Ne and H2 at liquid He temperatures show interesting differences as hosts of methyl radicals compared to Ar. Investigation of other possible causes of this difference, not excluding the experimentally controlled ones related to the sample preparation and the MW power saturation of the CW-EPR measurement, were conducted in this work.

Benetis, Nikolas P.; Dmitriev, Yurij

2009-03-01

429

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

430

Performance of a flameless combustion furnace using biogas and natural gas.  

PubMed

Flameless combustion technology has proved to be flexible regarding the utilization of conventional fuels. This flexibility is associated with the main characteristic of the combustion regime, which is the mixing of the reactants above the autoignition temperature of the fuel. Flameless combustion advantages when using conventional fuels are a proven fact. However, it is necessary to assess thermal equipments performance when utilizing bio-fuels, which usually are obtained from biomass gasification and the excreta of animals in bio-digesters. The effect of using biogas on the performance of an experimental furnace equipped with a self-regenerative Flameless burner is reported in this paper. All the results were compared to the performance of the system fueled with natural gas. Results showed that temperature field and uniformity are similar for both fuels; although biogas temperatures were slightly lower due to the larger amount of inert gases (CO(2)) in its composition that cool down the reactions. Species patterns and pollutant emissions showed similar trends and values for both fuels, and the energy balance for biogas showed a minor reduction of the efficiency of the furnace; this confirms that Flameless combustion is highly flexible to burn conventional and diluted fuels. Important modifications on the burner were not necessary to run the system using biogas. Additionally, in order to highlight the advantages of the Flameless combustion regime, some comparisons of the burner performance working in Flameless mode and working in conventional mode are presented. PMID:19944602

Colorado, A F; Herrera, B A; Amell, A A

2010-04-01

431

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

432

Mitral inertance in humans: critical factor in Doppler estimation of transvalvular pressure gradients  

NASA Technical Reports Server (NTRS)

The pressure-velocity relationship across the normal mitral valve is approximated by the Bernoulli equation DeltaP = 1/2 rhoDeltav(2) + M. dv/dt, where DeltaP is the atrioventricular pressure difference, rho is blood density, v is transmitral flow velocity, and M is mitral inertance. Although M is indispensable in assessing transvalvular pressure differences from transmitral flow, this term is poorly understood. We measured intraoperative high-fidelity left atrial and ventricular pressures and simultaneous transmitral flow velocities by using transesophageal echocardiography in 100 beats (8 patients). We computed mean mitral inertance (M) by M = integral((DeltaP)-(1/2 x rho v(2))dt/integral(dv/dt)dt and we assessed the effect of the inertial term on the transmitral pressure-flow relation. ranged from 1.03 to 5.96 g/cm(2) (mean = 3.82 +/- 1.22 g/cm(2)). DeltaP calculated from the simplified Bernoulli equation (DeltaP = 1/2. rhov(2)) lagged behind (44 +/- 11 ms) and underestimated the actual peak pressures (2.3 +/- 1.1 mmHg). correlated with left ventricular systolic pressure (r = -0.68, P < 0.0001) and transmitral pressure gradients (r = 0.65, P < 0.0001). Because mitral inertance causes the velocity to lag significantly behind the actual pressure gradient, it needs to be considered when assessing diastolic filling and the pressure difference across normal mitral valves.

Nakatani, S.; Firstenberg, M. S.; Greenberg, N. L.; Vandervoort, P. M.; Smedira, N. G.; McCarthy, P. M.; Thomas, J. D.

2001-01-01

433

Conceptual studies for pressurised water reactor cores employing plutonium erbium zirconium oxide inert matrix fuel assemblies  

NASA Astrophysics Data System (ADS)

The most efficient way to enhance plutonium consumption in light water reactors is to eliminate the production of plutonium all together. This requirement leads to fuel concepts in which the uranium is replaced by an inert matrix. At PSI, studies have focused on employing ZrO 2 as inert matrix. Adding a burnable poison to such a fuel proves to be necessary. As a result of scoping studies, Er 2O 3 was identified as the most suitable burnable poison material. The results of whole-core three-dimensional neutronics analyses indicated, for a present-day 1000 MW e pressurised water reactor (PWR), the feasibility of an asymptotic equilibrium four-batch cycle fuelled solely with the proposed PuO 2-Er 2O 3-ZrO 2 inert matrix fuel (IMF). The present paper presents the results of more recent investigations related to `real-life' situations, which call for transition configurations in which mixed IMF and UO 2 assembly loadings must be considered. To determine the influence of the introduction of IMF assemblies on the characteristics of a UO 2-fuelled core, three-dimensional full-core calculations have been performed for a present-day 1000 MW e PWR containing up to 12 optimised IMF assemblies.

Stanculescu, A.; Kasemeyer, U.; Paratte, J.-M.; Chawla, R.

1999-08-01

434

Reducing aluminum dust explosion hazards: case study of dust inerting in an aluminum buffing operation.  

PubMed

Metal powders or dusts can represent significant dust explosion hazards in industry, due to their relatively low ignition energy and high explosivity. The hazard is well known in industries that produce or use aluminum powders, but is sometimes not recognized by facilities that produce aluminum dust as a byproduct of bulk aluminum processing. As demonstrated by the 2003 dust explosion at aluminum wheel manufacturer Hayes Lemmerz, facilities that process bulk metals are at risk due to dust generated during machining and finishing operations [U.S. Chemical Safety and Hazard Investigation Board, Investigation Report, Aluminum Dust Explosion Hayes Lemmerz International, Inc., Huntington, Indiana, Report No. 2004-01-I-IN, September 2005]. Previous studies have shown that aluminum dust explosions are more difficult to suppress with flame retardants or inerting agents than dust explosions fueled by other materials such as coal [A.G. Dastidar, P.R. Amyotte, J. Going, K. Chatrathi, Flammability limits of dust-minimum inerting concentrations, Proc. Saf. Progr., 18-1 (1999) 56-63]. In this paper, an inerting method is discussed to reduce the dust explosion hazard of residue created in an aluminum buffing operation as the residue is generated. This technique reduces the dust explosion hazard throughout the buffing process and within the dust collector systems making the process inherently safer. Dust explosion testing results are presented for process dusts produced during trials with varying amounts of flame retardant additives. PMID:18423857

Myers, Timothy J

2008-11-15

435

Inert dusts and their effects on the poultry red mite (Dermanyssus gallinae).  

PubMed

The haematophagous poultry red mite (Dermanyssus gallinae) is the most important pest of egg laying hens in many parts of the world. Control has often relied on chemical pesticides, but inert dusts, which are thought to kill target hosts primarily by desiccation, have become one of the most commonly applied alternative control methods for poultry red mite in Europe. This development has occurred despite a lack of knowledge of the efficacy of the different types of inert dusts and how this is affected by environmental parameters, e.g. the high relative humidity found in poultry houses. In this laboratory study the efficacy of different commercial inert dust products against D. gallinae is compared. All tested compounds killed mites, but there was a clear ranking of efficacy (measured as weight loss after 24 h and as time until 50% mortality), particularly at 75% relative humidity (RH). At 85% RH the efficacy was significantly lower for all tested compounds (P < 0.001). Weight changes over time followed an exponential evaporation model until the mites started dying whereafter the rate of evaporation increased again and followed a slightly different exponential evaporation model. A tarsal test showed that 24 h exposure to surfaces treated with doses much lower than those recommended by the producers is sufficient to kill mites as fast as when they were dusted with massive doses. These data emphasise the need for thorough treatment of all surfaces in a poultry house in order to combat D. gallinae. PMID:19160061

Kilpinen, Ole; Steenberg, Tove

2009-06-01

436

High Efficiency CdTe/CdS Thin Film Solar Cells Prepared by Treating CdTe Films with a Freon Gas in Substitution of CdCl2  

E-print Network

in an atmosphere containing a non toxic gas that is inert at room temperature, namely HCFCl2. This belongs, inert and not toxic at room temperature. Besides it eliminates the step of CdCl2 evaporation and in recent years also in view of the hig

Romeo, Alessandro

437

Ion Bombardment Effect on Hydrogen Content in Boron Thin Films Prepared by Electron Cyclotron Resonance Discharge of Diluted Decaborane Gases  

NASA Astrophysics Data System (ADS)

Boron thin films are prepared by electron cyclotron resonance discharge of decaborane gas diluted with helium gas. The dependence of the hydrogen content in the films on the bias voltage V B applied to substrates is investigated at the substrate temperature of 200°C. The hydrogen content are 2 3 at. 6 11 at. and 9.3 at. The bombardment of the ions with energies more than 300 V during the deposition increases the hydrogen content in the boron thin films.

Ito, Yoshifumi; Nishikawa, Masahiro

1995-12-01

438

Effect of sputtering gas on the surface composition of an Al–Pd–Mn quasicrystal  

Microsoft Academic Search

We demonstrate the effects of different inert sputtering gases on the surface composition of icosahedral (i-) Al–Pd–Mn. The sputtering gases used include He, Ne, Ar, Xe, and Kr. We demonstrate that the steady-state composition is independent of the inert gas chosen. This steady-state composition falls outside of the quasicrystalline region of the Al–Pd–Mn phase diagram. However, the fluence (ions\\/cm2) to

Cynthia J Jenks; Joseph W Burnett; Drew W Delaney; Thomas A Lograsso; Patricia A Thiel

2000-01-01

439

Buoyancy and Dissolution of the Floating Crust Layer in Tank 241-SY-101 During Transfer and Back-Dilution  

SciTech Connect

To remediate gas retention in the floating crust layer and the potential for buoyant displacement gas releases from below the crust, waste will be transferred out of Hanford Tank 241-SY-101 (SY-101) in the fall of 1999 and back-diluted with water in several steps of about 100,000 gallons each. To evaluate the effects of back-dilution on the crust a static buoyancy model is derived that predicts crust and liquid surface elevations as a function of mixing efficiency and volume of water added during transfer and back-dilution. Experimental results are presented that demonstrate the basic physics involved and verify the operation of the models. A dissolution model is also developed to evaluate the effects of dissolution of solids on crust flotation. The model includes dissolution of solids suspended in the slurry as well as in the crust layers. The inventory and location of insoluble solids after dissolution of the soluble fraction are also tracked. The buoyancy model is applied to predict the crust behavior for the first back-dilution step in SY-101. Specific concerns addressed include conditions that could cause the crust to sink and back-dilution requirements that keep the base of the crust well above the mixer pump inlet.

CW Stewart; JH Sukamto; JM Cuta; SD Rassat

1999-11-22

440

Global NOx Measurements in Turbulent Nitrogen-Diluted Hydrogen Jet Flames  

SciTech Connect

Turbulent hydrogen diffusion flames diluted with nitrogen are currently being studied to assess their ability to achieve the DOE Turbine Program’s aggressive emissions goal of 2 ppm NOx in a hydrogen-fueled IGCC gas turbine combustor. Since the unstrained adiabatic flame temperatures of these diluted flames are not low enough to eliminate thermal NOx formation the focus of the current work is to study how the effects of flame residence time and global flame strain can be used to help achieve the stated NOx emissions goal. Dry NOx measurements are presented as a function of jet diameter nitrogen dilution and jet velocity for a turbulent hydrogen/nitrogen jet issuing from a thin-lipped tube in an atmospheric pressure combustor. The NOx emission indices from these experiments are normalized by the flame residence time to ascertain the effects of global flame strain and fuel Lewis Number on the NOx emissions. In addition dilute hydrogen diffusion flame experiments were performed in a high-pressure combustor at 2 4 and 8 atm. The NOx emission data from these experiments are discussed as well as the results from a Computational Fluid Dynamics modeling effort currently underway to help explain the experimental data.

Weiland, N.T.; Strakey, P.A.

2007-03-01

441

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

SciTech Connect

Experiments were conducted with ultra low sulfur diesel (ULSD) and 20% biodiesel blends (B20) to compare lube oil dilution levels and lubricant properties for systems using late in-cylinder fuel injection for aftertreatment regeneration. Lube oil dilution was measured by gas chromatography (GC) following ASTM method D3524 to measure diesel content, by Fourier transform infrared (FTIR) spectrometry following a modified ASTM method D7371 to measure biodiesel content, and by a newly developed back-flush GC method that simultaneously measures both diesel and biodiesel. Heavy-duty (HD) engine testing was conducted on a 2008 6.7L Cummins ISB equipped with a diesel oxidation catalyst (DOC) and diesel particle filter (DPF). Stage one of engine testing consisted of 10 consecutive repeats of a forced DPF regeneration event. This continuous operation with late in-cylinder fuel injection served as a method to accelerate lube-oil dilution. Stage two consisted of 16 hours of normal engine operation over a transient test cycle, which created an opportunity for any accumulated fuel in the oil sump to evaporate. Light duty (LD) vehicle testing was conducted on a 2010 VW Jetta equipped with DOC, DPF and a NOx storage catalyst (NSC). Vehicle testing comprised approximately 4,000 miles of operation on a mileage-accumulation dynamometer (MAD) using the U.S. Environmental Protection Agency's Highway Fuel Economy Cycle because of the relatively low engine oil and exhaust temperatures, and high DPF regeneration frequency of this cycle relative to other cycles examined. Comparison of the lube oil dilution analysis methods suggests that D3524 does not measure dilution by biodiesel. The new back-flush GC method provided analysis for both diesel and biodiesel, in a shorter time and with lower detection limit. Thus all lube oil dilution results in this paper are based on this method. Analysis of the HD lube-oil samples showed only 1.5% to 1.6% fuel dilution for both fuels during continuous operation under DPF regeneration events. During the second stage of HD testing, the ULSD lube-oil dilution levels fell from 1.5% to 0.8%, while for B20, lube-oil dilution levels fell from 1.6% to 1.0%, but the fuel in the oil was 36% biodiesel. For the LD vehicle tests, the frequency of DPF regeneration events was observed to be the same for both ULSD and B20. No significant difference between the two fuels' estimated soot loading was detected by the engine control unit (ECU), although a 23% slower rate of increase in differential pressure across DPF was observed with B20. It appears that the ECU estimated soot loading is based on the engine map, not taking advantage of the lower engine-out particulate matter from the use of biodiesel. After 4,000 miles of LD vehicle operation with ULSD, fuel dilution in the lube-oil samples showed total dilution levels of 4.1% diesel. After 4,000 miles of operation with B20, total fuel in oil dilution levels were 6.7% consisting of 3.6% diesel fuel and 3.1% biodiesel. Extrapolation to the 10,000-mile oil drain interval with B20 suggests that the total fuel content in the oil could reach 12%, compared to 5% for operation on ULSD. Analysis of the oil samples also included measurement of total acid number, total base number, viscosity, soot, metals and wear scar; however, little difference in these parameters was noted.

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

2011-12-01

442

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

443

Measurements of activity coefficients at infinite dilution of aliphatic and aromatic hydrocarbons, alcohols, thiophene, tetrahydrofuran, MTBE, and water in ionic liquid [BMIM][SCN] using GLC  

Microsoft Academic Search

The activity coefficients at infinite dilution, ?13? for 32 solutes: alkanes, alken-1-es, alkyn-1-es, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, tetrahydrofuran, tert-butyl methyl ether, and water in the ionic liquid 1-butyl-3-methylimidazolium thiocyanate [BMIM][SCN] were determined by gas-liquid chromatography at the temperatures from 298.15K to 368.15K. The values of the partial molar excess enthalpies at infinite dilution ?H1E,? were calculated from the experimental

Urszula Doma?ska; Marta Laskowska

2009-01-01

444

A century of indicator dilution technique.  

PubMed

This review imparts the history and the present status of the indicator dilution technique with quantitative bolus injection. The first report on flow measurement with this technique appeared 100 years ago. In 1928, the use of intravascular dyes made possible a widespread application in animals and human during the next decades. Multiple indicators, radioactive tracers, inlet-outlet detection and residue detection were introduced in the 1950s and 1960s, and refined along with the development of indicator kinetics. From the 1970s, a wide clinical use in the study of heart, brain, lungs, liver and kidneys developed, and powerful computers in the 1980s and 1990s accorded the technique a new dimension. Today, the indicator dilution technique, on one hand, is applied in the same way as 100 years ago, on the other hand it forms the basis of quantitative SPECT, positron emission tomography, and dynamic MR scans. The technique still undergoes refinement and elaboration as a lasting concept with a high potential for further development. PMID:23869947

Henriksen, Jens H; Jensen, Gorm B; Larsson, Henrik B W

2014-01-01

445

40 CFR 90.420 - CVS concept of exhaust gas sampling system.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false CVS concept of exhaust gas sampling system. 90.420 Section 90.420 ...§ 90.420 CVS concept of exhaust gas sampling system. (a) A dilute exhaust sampling system is designed to directly...

2010-07-01

446

40 CFR 91.420 - CVS concept of exhaust gas sampling system.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false CVS concept of exhaust gas sampling system. 91.420 Section 91.420 ...§ 91.420 CVS concept of exhaust gas sampling system. (a) A dilute exhaust sampling system is designed to directly...

2010-07-01

447

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

448

Low Burnup Inert Matrix Fuels Performance: TRANSURANUS Analysis of the Halden IFA-652 First Irradiation Cycle  

SciTech Connect

The inert matrix fuels are a promising option to reduce-eliminate worldwide plutonium stockpiles by burning it in LWRs. These fuels, where plutonium is hosted in a U-free inert matrix phase, may reach high burning efficiency while preventing new plutonium build-up under irradiation. A specific investigation on CSZ and thoria inert matrices has been developed by ENEA since several years. In-pile testing on the ENEA-conceived innovative fuels is ongoing in the OECD Halden HBWR since June 2000 (IFA-652 experiment). The registered burnup at the end of 2005 is about 38 MWd.kgU{sub eq}{sup -1} vs. 45 MWd.kgU{sub eq}{sup -1} (40 MWd.kgUOX{sub eq}{sup -1}) target. Fuel pins are equipped with fuel temperature thermocouples, internal pressure transducers and fuel stack elongation sensors, with the task of studying thermal conductivity and its degradation with burnup, densification-swelling behaviour and the FGR. In this paper, the response at low burnup (< 7 MWd.kgU{sub eq}{sup -1}) of CSZ-based fuels loaded in IFA-652, is analysed by means of the TRANSURANUS code. To this purpose, a comprehensive modelling of the above mentioned un-irradiated fuels, mainly relying on the thermophysical characterisation performed at the JRC/ITU-Karlsruhe, has been implemented in a custom TRANSURANUS version (TU-IMF). A comparison of the code predictions vs. the experimental data, aimed at evaluating the early-stage under irradiation phenomena, particularly densification and relocation, has been performed. (authors)

Calabrese, R.; Vettraino, F. [ENEA, Nuclear Fission Division, via Martin di Monte Sole 4, 40129 Bologna (Italy); Tverberg, T. [OECD Halden Reactor Project, Institutt for energiteknikk, P.O. Box 175, N-1751 Halden (Norway)

2006-07-01

449

Copper Gas Diffusers For Purging Line-Focus Laser Welds  

NASA Technical Reports Server (NTRS)

Modified flow diffusers built for inert-gas purging of welds made with 5-kW CO(2) lasers operating with line-focus optics in conduction mode instead of with point-focus optics in customary keyhole mode. Diffusers made of copper components brazed together, robust enough to withstand strong reflections of line-focused laser energy.

Fonteyne, Steve L.; Hosking, Timothy J.; Shelley, D. Mark

1996-01-01

450

Thermal stability of distorted gas flame in porous media  

Microsoft Academic Search

The stability of a plane flame front with respect to spatial perturbations is investigated for chemically inert media. The influence of the gas-filtration rate on the stability is analyzed. In the long-wave approximation, the dependence of the flame front velocity on the surface curvature is obtained.

S. S. Minaev; S. I. Potytnyakov; V. S. Babkin

1994-01-01

451

Hydrogen-selective thermoelectric gas sensor  

Microsoft Academic Search

A thermoelectric (TE) hydrogen gas sensor was fabricated by depositing a platinum catalyst thin film on the half surface of nickel oxide thick film. When it was exposed to combustible gas diluted by synthetic air, the catalyst layer converts hydrogen and oxygen effectively to water vapor, and give out heat energy, resulting temperature difference across the sensor, and consequently voltage

Woosuck Shin; Masahiko Matsumiya; Noriya Izu; Norimitsu Murayama

2003-01-01

452

Heat conductivity of a pion gas  

E-print Network

We evaluate the heat conductivity of a dilute pion gas employing the Uehling-Uehlenbeck equation and experimental phase-shifts parameterized by means of the SU(2) Inverse Amplitude Method. Our results are consistent with previous evaluations. For comparison we also give results for an (unphysical) hard sphere gas.

Antonio Dobado Gonzalez; Felipe J. Llanes-Estrada; Juan M. Torres Rincon

2007-02-13

453

Final report on the characterization of the film on inert anodes  

SciTech Connect

Results of post-test microscopic and elemental analysis of the reaction zone on polarized cermet inert anodes, over a range of current densities and alumina concentrations, suggest that an alumina film does not form to protect the anode from dissolution. Rather, significant morphological and compositional changes occur at or near the anode surface. These changes and the chemical reactions that cause them involve the cermet material itself and appear to be responsible for properties that were previously assigned to an alumina film. In particular, a reaction layer formed from the cermet material may have protective properties, while changes in roughness and porosity may contribute to the electrochemical impedance.

Windisch, C.F. Jr.; Stice, N.D.

1991-01-01

454

Evaluation of selected trivalent metal oxides as inert markers used to estimate apparent digestibility in salmonids  

Microsoft Academic Search

Trivalent oxides of yttrium and rare earth metals were evaluated as inert markers in apparent digestibility studies with salmonids in four experiments. In Experiment 1, 100 mg kg?1 of each of 15 oxides (Dy2O3, Er2O3, Eu2O3, Gd2O3, Ho2O3, La2O3, Lu2O3, Nd2O3, Pr2O3, Sc2O3, Sm2O3, Tb(III and IV) oxide, Tm2O3, Y2O3 and Yb2O3) were included in a feed fed to rainbow

Erland Austreng; Trond Storebakken; Magny Skinlo Thomassen; Ståle Refstie; Yngvar Thomassen

2000-01-01

455

Inert Anode/Cathode Program: Fiscal Year 1986 annual report. [For Hall-Heroult cells  

SciTech Connect

Purpose of the program is to develop long-lasting, energy-efficient anodes, cathodes, and ancillary equipment for Hall-Heroult cells used by the aluminum industry. The program is divided into four tasks: Inert Anode Development, Cathode Materials Evaluation, Cathode Bonding Development, and Sensor Development. To devise sensors to control the chemistry of Hall-Heroult cells using stable anodes and cathodes. This report highlights the major FY86 technical accomplishments, which are presented in the following sections: Management, Materials Development, Materials Evaluation, Thermodynamic Evaluation, Laboratory Cell Tests, Large-Scale Tests, Cathode Materials Evaluation, Cathode Bonding Development, and Sensor Development.

Brenden, B.B.; Davis, N.C.; Koski, O.H.; Marschman, S.C.; Pool, K.H.; Schilling, C.H.; Windisch, C.F.; Wrona, B.J.

1987-06-01

456

Catalytic performance of limonite in the decomposition of ammonia in the coexistence of typical fuel gas components produced in an air-blown coal gasification process  

SciTech Connect

Catalytic decomposition of 2000 ppm NH{sub 3} in different atmospheres with an Australian {alpha}-FeOOH-rich limonite ore at 750-950{sup o}C under a high space velocity of 45000 h{sup -1} has been studied with a cylindrical quartz reactor to develop a novel hot gas cleanup method of removing NH{sub 3} from fuel gas produced in an air-blown coal gasification process for an integrated gasification combined cycle (IGCC) technology. The limonite shows very high catalytic activity for the decomposition of NH{sub 3} diluted with inert gas at 750{sup o}C, regardless of whether the catalyst material is subjected to H{sub 2} reduction before the reaction or not. Conversion of NH{sub 3} to N{sub 2} over the reduced limonite reaches {ge}99% at 750-950{sup o}C, and the catalyst maintains the high performance for about 40 h at 750{sup o}C. When the decomposition reaction is carried out in the presence of fuel gas components, the coexistence of syngas (20% CO/10% H{sub 2}) causes not only the serious deactivation of the limonite catalyst but also the appreciable formation of deposited carbon and CO{sub 2}. On the other hand, the addition of 10% CO{sub 2} or 3% H{sub 2}O to the syngas improves the catalytic performance and concurrently suppresses the carbon deposition almost completely, and the NH{sub 3} conversion in the 3% H{sub 2}O-containing syngas reaches about 90% and almost 100% at 750 and 850 {sup o}C, respectively. Influential factors controlling the catalytic activity of the limonite ore in the coexistence of fuel gas components are discussed on the basis of the results of the powder X-ray diffraction measurements, thermodynamic calculations, and some model experiments. 16 refs., 11 figs., 1 tab.

Naoto Tsubouchi; Hiroyuki Hashimoto; Yasuo Ohtsuka [Tohoku University, Katahira, Sendai (Japan). Research Center for Sustainable Materials Engineering

2007-12-15

457

Dilution Jet Mixing Program, phase 1  

NASA Technical Reports Server (NTRS)

The effect of jet to mainstream density ratio, flow area convergence as encounted in transition sections, and nonuniform mainstream profile upstream of dilution orifices on the mixing of a row of jets with a confined cross flow was quantified. It is found that: (1) jet spreading rate in transverse direction is increased with increasing J, H/D and with decreasing S/D; (2) the density ratio has only a second order effect on the jet mixing characteristics for a constant momentum ratio; (3) the temperature distributions in the jet mixing region are strongly influenced by the undisturbed mainstream profile; (4) flow area convergence enhances mixing in radial and transverse directions. An asymmetric convergent duct with flat wall injection has the same jet mixing characteristics as a symmetric convergent duct. An asymmetric convergent duct with slant wall injection has a faster jet spreading rate in the transverse direction.

Srinivasan, R.; Berenfeld, A.; Mongia, H. C.

1982-01-01

458

Are Room Temperature Ionic Liquids Dilute Electrolytes?  

E-print Network

An important question in understanding the structure of ionic liquids is whether ions are truly "free" and mobile which would correspond to a concentrated ionic melt, or are rather "bound" in ion pairs, that is a liquid of ion pairs with a small concentration of free ions. Recent surface force balance experiments from different groups have given conflicting answers to this question. We propose a simple model for the thermodynamics and kinetics of ion pairing in ionic liquids. Our model takes into account screened ion-ion, dipole-dipole and dipole-ion interactions in the mean field limit. The results of this model suggest that almost two thirds of the ions are free at any instant, and ion pairs have a short lifetime comparable to the characteristic timescale for diffusion. These results suggest that there is no particular thermodynamic or kinetic preference for ions residing in pairs. We therefore conclude that ionic liquids are concentrated, rather than dilute, electrolytes.

Lee, Alpha A; Perkin, Susan; Goriely, Alain

2014-01-01

459

Hydration structure in dilute hydrofluoric acid.  

PubMed

We have performed the multistate empirical valence bond (MS-EVB) molecular dynamics simulations of a dilute hydrofluoric acid solution at ambient temperature to study the hydration structure associated with its weak acidity. The developed MS-EVB model showed reasonable agreement with experimental and previous ab initio molecular dynamics and reference interaction site model self-consistent field simulations for the free energy and structural properties. The local tetrahedral and translational order parameters around the fluorine atom significantly increase in the transition and product states of the HF dissociation reaction. This indicates that the angular and translational rearrangements of the hydrogen-bond topology are necessary especially around the fluorine atom. At the transition state of the proton transfer, the tetrahedral order parameters are very large, whereas the translational order parameters are not. This suggests that for the proton transfer to occur the large angular rearrangements of the hydrogen-bond topology are more necessary than the translational ones. PMID:21210669

Joutsuka, Tatsuya; Ando, Koji

2011-02-10

460

Efficient removal of UDMH from dilute nitride MOCVD exhaust streams  

NASA Astrophysics Data System (ADS)

Unsymmetrical dimethyl hydrazine (UDMH) (CH 3) 2N 2H 2 is often used in the deposition of dilute nitride semiconductors because it provides a source of nitrogen with a low thermal decomposition temperature (Temperature-dependent carrier lifetime in GaNAs using resonant-coupled photoconductive decay, NCPV Program Review Meeting, Lakewood, Colorado, 14-17 October, 2001). The problems with using this material, however, are its significant toxicity (0.01 ppm compared to ammonia's 25 ppm) and also the fact that it blocks the action of conventional dosed wet scrubbers sometimes used on nitride applications, resulting in diminished efficiency in removing arsine (the source of arsenic), and arsine being similarly toxic (TLV of 0.05 ppm). Efficient removal of UDMH, AsH 3 and hydrogen (which, though not toxic poses a potential safety hazard) by means of a combined thermal oxidation reaction and wet scrubber in series is described at input gas flow rates exceeding those typically encountered in practice. The detection technique employed was Fourier transform infra red spectroscopy (FTIR), and the calibration and resolution techniques will be described. For input UDMH flows of up to 445 sccm (i.e. 1.85×10 -2 mol/min), destructive reaction efficiencies (DREs) of >99.9% were demonstrated, corresponding to the background detection resolution of 0.4 ppm.

Pahle, Jörg; Czerniak, Mike; Seeley, Andy; Baker, Derek

2004-12-01