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1

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

2

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

3

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

4

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

5

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

6

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

7

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

8

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

9

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

10

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

11

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

12

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

13

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

14

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

15

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

16

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

17

46 CFR 154.908 - Inert gas generator: Location.  

Code of Federal Regulations, 2010 CFR

... 2010-10-01 false Inert gas generator: Location. 154.908 Section 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

18

46 CFR 154.908 - Inert gas generator: Location.  

Code of Federal Regulations, 2012 CFR

... 2012-10-01 false Inert gas generator: Location. 154.908 Section 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

19

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

20

46 CFR 154.908 - Inert gas generator: Location.  

Code of Federal Regulations, 2014 CFR

... 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

21

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

22

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

23

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

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

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

NASA Astrophysics Data System (ADS)

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

Bharathan, D.; Althof, J.

1984-08-01

30

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

31

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

32

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

33

Synthesis and deposition of metal nanoparticles by gas condensation process  

SciTech Connect

In this work, the synthesis of Pt and Ag nanoparticles by means of the inert gas phase condensation of sputtered atomic vapor is presented. The process parameters (power, sputtering time, and gas flow) were varied in order to study the relationship between deposition conditions and properties of the nanoparticles such as their quantity, size, and size distribution. Moreover, the gas phase condensation process can be combined with a plasma enhanced chemical vapor deposition procedure in order to deposit nanocomposite coatings consisting of metallic nanoparticles embedded in a thin film matrix material. Selected examples of application of the generated nanoparticles and nanocomposites are discussed.

Maicu, Marina, E-mail: marina.maicu@fep.fraunhofer.de; Glöß, Daniel; Frach, Peter [Fraunhofer Institut für Elektronenstrahl und Plasmatechnik, FEP, Winterbergstraße 28, 01277 Dresden (Germany); Schmittgens, Ralph; Gerlach, Gerald [Institut für Festkörperelektronik, IFE, TU Dresden, Helmholtz Straße 18, 01069 Dresden (Germany); Hecker, Dominic [Fraunhofer Institut für Elektronenstrahl und Plasmatechnik, FEP, Winterbergstraße 28, 01277 Dresden, Germany and Institut für Festkörperelektronik, IFE, TU Dresden, Helmholtz Straße 18, 01069 Dresden (Germany)

2014-03-15

34

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

35

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

36

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

37

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

38

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

39

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

40

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

41

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

42

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

43

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

44

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

45

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

46

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

47

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

48

Size-controlled Pd nanocluster grown by plasma gas-condensation method  

Microsoft Academic Search

Syntheses of palladium (Pd) nanoclusters by sputtering gas-condensation technique are reported in this work. The Pd nanocluster\\u000a size distribution and number of nanoclusters are found to depend on several factors which include the inert gas flow rate\\u000a (f), sputtering discharge power, and growth region length. The discharge power and the length of the growth region are optimized\\u000a to produce high

A. I. Ayesh; S. Thaker; N. Qamhieh; H. Ghamlouche

2011-01-01

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

Gas condensate damage in hydraulically fractured wells  

E-print Network

GAS CONDENSATE DAMAGE IN HYDRAULICALLY FRACTURED WELLS A Thesis by REZA ROSTAMI RAVARI Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE August 2004 Major Subject: Petroleum Engineering GAS CONDENSATE DAMAGE IN HYDRAULICALLY FRACTURED WELLS A Thesis by REZA ROSTAMI RAVARI Submitted to Texas A&M University in partial...

Reza, Rostami Ravari

2004-11-15

52

KPIM of Gas\\/Condensate Productivity: Prediction of Condensate\\/Gas Ratio Using Reservoir Volumetric Balance  

Microsoft Academic Search

A new approach for forecasting viability of gas condensate wells and calculating Condensate Gas Ratio (CGR), using simpler techniques is presented. The calculation uses a volumetric balance model for reservoir system, standardized and modified correlations, equation of state and a vapor-liquid equilibrium technique. The technique has been extended to include mass transfer and also to allow for the changes in

A. F. Olaberinjo; M. O. Oyewola; O. A. Obiyemi; O. A. Adeyanju; M. S. Adaramola

2006-01-01

53

Optimization of condensing gas drive  

E-print Network

- cal, undersaturated reservoir with gas being injected into the crest and oil being produced from the base of the structure. Fractional oil re- covery at gas breakthrough proved to be less sensitive to changes in oil withdrawal rates as the gas... of gravity will result when gas is injected into the crest and oil produced from the base of a vertical reservoir. 4 Terwilliger, et al. demonstrated that fractional oil recovery at gas breakthrough is inversely proportional to the oil withdrawal rate...

Lofton, Larry Keith

1977-01-01

54

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

55

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

56

Characterization of KILnGAS process condensate  

SciTech Connect

In recent years, a great deal of development work has been done on processes and hardware directly related to coal gasification. These gasification processes produce wastewaters containing varying amounts of dissolved organics, ammonia, and other contaminants. Samples of process condensate obtained from the 600-tpd KILnGAS demonstration unit at Alton, Illinois, were obtained during plant operation in November and December of 1984. The samples were preserved and sent to Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee, where they were subjected to detailed characterization. The results of these analyses indicate that the KILnGAS process condensate is similar to many other gasification wastewaters. Subject to experimental verification, these results indicate that KILnGAS process condensate treatment should be possible by conventional technology. 1 fig., 4 tabs.

Walker, J.F. Jr.; Brown, C.H. Jr.; Fisher, J.F.

1985-01-01

57

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

58

Gas condensate damage in hydraulically fractured wells  

E-print Network

This project is a research into the effect of gas condensate damage in hydraulically fractured wells. It is the result of a problem encountered in producing a low permeability formation from a well in South Texas owned by the El Paso Production...

Adeyeye, Adedeji Ayoola

2004-09-30

59

Condensed Combustion Products of Aluminized Propellants. III. Effect of an Inert Gaseous Combustion Environment  

Microsoft Academic Search

The effect of gaseous combustion environment on particle size distribution and chemical compositions of condensed combustion products of a model propellant containing ammonium perchlorate, binder, and 23.4% aluminum was studied. Experiments were conducted at pressures of 0.6, 4.0, and 7.5MPa. Oxide particles with sizes of 1.2–60 µm and agglomerates with sizes from 60 µm to maximum were investigated. In experiments

O. G. Glotov

2002-01-01

60

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

PubMed

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

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

2014-11-17

61

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

62

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

63

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

64

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

65

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

66

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

67

Condensation Chemistry in Radioactive Supernova Gas  

NASA Astrophysics Data System (ADS)

New kinetic chemical paths are created during condensation by radioactivity. Supernova radioactivity not only dominates light curves, gamma rays and high excitation but also the chemistry of dust condensation. Dust normally is either C or oxides depending on whether C or O has greater abundance. Compton electrons dissociate the CO molecule in about one month, however, maintaining free atomic carbon at decreasing temperature. Our chemical model of SN1987A shows that linear C chains establish a near equilibrium between formation and destruction even when O > C. Isomerization to ringed carbon above n=24 atoms greatly reduces oxidation rates for them, enabling those rare seeds to grow to micron size during expansion time. In gas having C = O their abundances per C atom at 500d decline with C-atom number n as n-2/3 from N_24/N(C) = 10-20 at n=24. The abundances are less if C < O, but final graphite sizes are not. Maximum number is near n=10^15. Most carbon mass is calculated to lie in the largest graphite spheres, having mass fraction X=10-5 relative to C. This is comparable to the C mass fraction of micrometer SN graphite grains found in meteorites. Radiogenic ^44Ca from ^44Ti decay after C condensation establishes the supernova source for these condensates. Their total opacity suffices to shift emission lines in 87A blueward after 500d and also emits significant infrared luminosity. Parallel kinetic rates determine trace isotopes in the meteoritic SN graphites. The chemistry is kinetic rather than thermal equilibrium and is made possible by radiodeactivation of the CO trap for C. The ejected CO mass is an inverse measure of the ejected ^56Ni mass. A new chemical astronomy of supernova solids depends in these ways on the SN radioactivity.

Clayton, Donald; Liu, Weihong

1999-11-01

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

Spark gap switch system with condensable dielectric gas  

DOEpatents

A spark gap switch system is disclosed which is capable of operating at a high pulse rate comprising an insulated switch housing having a purging gas entrance port and a gas exit port, a pair of spaced apart electrodes each having one end thereof within the housing and defining a spark gap therebetween, an easily condensable and preferably low molecular weight insulating gas flowing through the switch housing from the housing, a heat exchanger/condenser for condensing the insulating gas after it exits from the housing, a pump for recirculating the condensed insulating gas as a liquid back to the housing, and a heater exchanger/evaporator to vaporize at least a portion of the condensed insulating gas back into a vapor prior to flowing the insulating gas back into the housing.

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

1991-01-01

71

Vapor condensation in the presence of a noncondensable gas  

SciTech Connect

Kinetic theory principles are used to study one-dimensional steady-state vapor condensation phenomena in the presence of a noncondensable gas. The results have been fitted to an interpolation formula describing the condensation flux that reduces to the one obtained by Labuntsov and Kryukov (Int. J. Heat Mass Transfer 22, 989 (1979)) in the limit of no noncondensable gas.

Pong, L.; Moses, G.A.

1986-06-01

72

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

73

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

74

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

75

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

76

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

77

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

78

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

79

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

80

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

81

CFD simulation of water vapour condensation in the presence of non-condensable gas in vertical cylindrical condensers.  

PubMed

This paper presents the simulation of the condensation of water vapour in the presence of non-condensable gas using computational fluid dynamics (CFD) for turbulent flows in a vertical cylindrical condenser tube. The simulation accounts for the turbulent flow of the gas mixture, the condenser wall and the turbulent flow of the coolant in the annular channel with no assumptions of constant wall temperature or heat flux. The condensate film is assumed to occupy a negligible volume and its effect on the condensation of the water vapour has been taken into account by imposing a set of boundary conditions. A new strategy is used to overcome the limitation of the currently available commercial CFD package to solve the simultaneous simulation of flows involving multispecies and fluids of gas and liquid in separate channels. The results from the CFD simulations are compared with the experimental results from the literature for the condensation of water vapour with air as the non-condensable gas and for inlet mass fraction of the water vapour from 0.66 to 0.98. The CFD simulation results in general agree well with the directly measured quantities and it is found that the variation of heat flux in the condenser tube is more complex than a simple polynomial curve fit. The CFD results also show that, at least for flows involving high water vapour content, the axial velocity of the gas mixture at the interface between the gas mixture and the condensate film is in general not small and cannot be neglected. PMID:24850953

Li, Jun-De

2013-02-01

82

CFD simulation of water vapour condensation in the presence of non-condensable gas in vertical cylindrical condensers  

PubMed Central

This paper presents the simulation of the condensation of water vapour in the presence of non-condensable gas using computational fluid dynamics (CFD) for turbulent flows in a vertical cylindrical condenser tube. The simulation accounts for the turbulent flow of the gas mixture, the condenser wall and the turbulent flow of the coolant in the annular channel with no assumptions of constant wall temperature or heat flux. The condensate film is assumed to occupy a negligible volume and its effect on the condensation of the water vapour has been taken into account by imposing a set of boundary conditions. A new strategy is used to overcome the limitation of the currently available commercial CFD package to solve the simultaneous simulation of flows involving multispecies and fluids of gas and liquid in separate channels. The results from the CFD simulations are compared with the experimental results from the literature for the condensation of water vapour with air as the non-condensable gas and for inlet mass fraction of the water vapour from 0.66 to 0.98. The CFD simulation results in general agree well with the directly measured quantities and it is found that the variation of heat flux in the condenser tube is more complex than a simple polynomial curve fit. The CFD results also show that, at least for flows involving high water vapour content, the axial velocity of the gas mixture at the interface between the gas mixture and the condensate film is in general not small and cannot be neglected. PMID:24850953

Li, Jun-De

2013-01-01

83

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

84

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

85

Effect of non-condensable gas on vapor flow in the condenser of VCHP  

Microsoft Academic Search

A fundamental study of the effect of noncondensable gas on a vapor flow in the condenser region of VCHP (variable conductance heat pipe) was conducted experimentally and analytically. In the experiment, a specific thermosyphon or a wickless VCHP model was fabricated which has a condenser of rectangular cross sectional area to realize two-dimensional flow field. Detailed flow field surveys conducted

Yasunori Kobayashi; Akira Okumura; Toshihisa Matsue

1989-01-01

86

Mathematical simulation of the process of condensing natural gas  

NASA Astrophysics Data System (ADS)

Presents a two-dimensional unsteady model of heat transfer in terms of condensation of natural gas at low temperatures. Performed calculations of the process heat and mass transfer of liquefied natural gas (LNG) storage tanks of cylindrical shape. The influence of model parameters on the nature of heat transfer. Defined temperature regimes eliminate evaporation by cooling liquefied natural gas. The obtained dependence of the mass flow rate of vapor condensation gas temperature. Identified the possibility of regulating the process of "cooling down" liquefied natural gas in terms of its partial evaporation with low cost energy.

Tastandieva, G. M.

2015-01-01

87

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

88

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

89

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

90

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

91

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

92

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

93

New inflow performance relationships for gas condensate reservoirs  

E-print Network

....................................................................................................(1.5) Similarly, using Eq. 1.2 or Eq. 1.4 to solve for the rate at any time, we have: )1 wf psso pb ? ....................................................................................................................(1.6) Dividing Eq. 1....13 GRACE versus GRACE + polynomial regression (Case 9) ? dry gas...................................... 66 4.14 Example 5 ? gas condensate (? o= 0.22 measured) .................................................................... 68 4.15 Example 5...

Del Castillo Maravi, Yanil

2004-09-30

94

Mechanisms of Liquid Buildup in Gas Condensate Reservoirs  

Microsoft Academic Search

Gas condensate reservoirs are different from dry and wet gas reservoirs in many cases, and these differences lead to weird and wonderful properties. When reservoir pressure falls below dew point, liquid dropout and its saturation may increase to a point that could flow. Therefore, in a reservoir three different regions are developed with different effects on well productivity. The authors

M. Qassamipour; A. Hashemi

2011-01-01

95

TBP and chromatographic data for gas condensates characterisation  

Microsoft Academic Search

Gas condensate fluids require accurate characterization for use in the equations of state used in reservoir modelling for field development planning. The most useful data for the computations are determined from single carbon number (SCN) fractions which are obtained by True Boiling Point (TBP) distillations and high precision gas chromatography (GC). TBP analysis requires careful calibration and operation to minimize

Raffie Hosein; Richard A. Dawe

2011-01-01

96

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

97

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

98

Condensed phase rare gas halide exciplex lasers  

Microsoft Academic Search

XeF-doped solid argon constitutes the first solid state exciplex laser in which lasing action over the B to X, C to A, and D to X bands have been demonstrated. The results of these studies are summarized. Generalization of principles to other members of the large family of condensed phase exciplexes is considered. Ternary X:Rg:Rg-prime solids in which the diatomic

V. A. Apkarian

1990-01-01

99

Gas condensate reservoir characterisation for CO2 geological storage  

NASA Astrophysics Data System (ADS)

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

Ivakhnenko, A. P.

2012-04-01

100

Use of Two-Phase Pseudo Pressure Method to Calculate Condensate Bank Size and Well Deliverability in Gas Condensate Reservoirs  

Microsoft Academic Search

This paper introduces a novel approach in the use of two-phase pseudo pressures for the calculation of condensate bank radius and productivity index of wells and the interpretation of gas condensate well test data. It is shown that knowledge of the relationship between condensate saturation and pressure is necessary for the integration of pseudo pressure in all regions of the

Jalal Mazloom; Fariborz Rashidi

2006-01-01

101

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

102

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

103

Industrial Research of Condensing Unit for Natural Gas Boiler House  

NASA Astrophysics Data System (ADS)

In the course of work industrial research was carried out at the boiler plant A/S "Imanta" where a 10MW passive condensing economizer working on natural gas was installed after the 116MW water boiler. The work describes the design of the condensing economizer and wiring diagram. During the industrial experiment, the following measurements were made: the temperature of water before and after the economizer; the ambient temperature; the quantity of water passing through the economizer; heat, produced by the economizer and water boilers. The work summarizes the data from 2010-2011.

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

2012-12-01

104

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

105

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

SciTech Connect

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

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

2011-01-17

106

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

107

Modeling condensation with a noncondensable gas for mixed convection flow  

NASA Astrophysics Data System (ADS)

This research theoretically developed a novel mixed convection model for condensation with a noncondensable gas. The model developed herein is comprised of three components: a convection regime map; a mixed convection correlation; and a generalized diffusion layer model. These components were developed in a way to be consistent with the three-level methodology in MELCOR. The overall mixed convection model was implemented into MELCOR and satisfactorily validated with data covering a wide variety of test conditions. In the development of the convection regime map, two analyses with approximations of the local similarity method were performed to solve the multi-component two-phase boundary layer equations. The first analysis studied effects of the bulk velocity on a basic natural convection condensation process and setup conditions to distinguish natural convection from mixed convection. It was found that the superimposed velocity increases condensation heat transfer by sweeping away the noncondensable gas accumulated at the condensation boundary. The second analysis studied effects of the buoyancy force on a basic forced convection condensation process and setup conditions to distinguish forced convection from mixed convection. It was found that the superimposed buoyancy force increases condensation heat transfer by thinning the liquid film thickness and creating a steeper noncondensable gas concentration profile near the condensation interface. In the development of the mixed convection correlation accounting for suction effects, numerical data were obtained from boundary layer analysis for the three convection regimes and used to fit a curve for the Nusselt number of the mixed convection regime as a function of the Nusselt numbers of the natural and forced convection regimes. In the development of the generalized diffusion layer model, the driving potential for mass transfer was expressed as the temperature difference between the bulk and the liquid-gas interface using the Clausius-Clapeyron equation. The model was developed on a mass basis instead of a molar basis to be consistent with general conservation equations. It was found that vapor diffusion is not only driven by a gradient of the molar fraction but also a gradient of the mixture molecular weight at the diffusion layer.

Liao, Yehong

2007-05-01

108

The effect of condensate dropout on pressure transient analysis of a high-pressure gas condensate well  

E-print Network

THE EFFECT OF CONDENSATE DROPOUT ON PRESSURE TRANSIENT ANALYSIS OF A HIGH-PRESSURE GAS CONDENSATE NELL A thesis FREDERIC JEAN-LOUIS BRIENS Submitted to the Graduate College of Texas A&M University in partial fulfillement of the requirements i...'or the degree of MASTER OF SCIENCE August 1986 Major Subject : Petr oleum Engineering THE EFFECT OF CONDENSATE DROPOUT ON PRESSURE TRANSIENT ANALYSIS OF A HIGH-PRESSURE GAS CONDENSATE WELL A thesis by FREDERIC JEAN-LOUiS SRIENS Approved as to style...

Briens, Frederic Jean-Louis

1986-01-01

109

Quasione and quasitwodimensional perfect Bose gas: the second critical density and generalised condensation  

E-print Network

condensation Mathieu Beau and Valentin A. Zagrebnov Universitâ??e de la Mâ??editerranâ??ee and Centre de Physique Th) In this letter we discuss a relevance of the 3D Perfect Bose gas (PBG) condensation in extremely elongated vessels for the study of anisotropic condensate coherence and the ''quasi­condensate''. To this end we

Recanati, Catherine

110

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

111

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

112

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.

113

Effect of Non-condensable gas on Solutal Marangoni Condensation Heat Transfer Characteristics for Water-Ethanol Vapor Mixture  

NASA Astrophysics Data System (ADS)

The condensation heat transfer characteristic curves for ternary vapor mixture of water, ethanol and air (or nitrogen) under the ethanol mass fraction of 0.01, 0.07, 0.25, 0.45 and relatively low concentrations of air (or nitrogen) were measured.The effect of air (or nitrogen) as a non-condensable gas on several different domains in the Marangoni condensation characteristic curves was discussed. It was shown that the effect of non-condensable gas in the domains controlled by the diffusion resistance and the filmwise condensation was not notable but in the domain dominated by the condensate resistance of dropwise mode was remarkable. Moreover, the variations of the several characteristic points representing the characteristic curves caused by the change in non-condensable gas concentration were discussed. The deteriorations of the maximum heat transfer coefficient and the maximum heat flux for low ethanol concentration and low concentration of non-condensable gas, in which the excellent heat transfer characteristics were exhibited, were more remarkable.

Wang, Shixue; Utaka, Yoshio

114

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

E-print Network

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

Narayan, G. Prakash

115

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

NASA Technical Reports Server (NTRS)

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

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

1976-01-01

116

Bose Einstein condensation in a gas of the Fibonacci oscillators  

E-print Network

We consider a system of the two-parameter deformed boson oscillators whose spectrum is given by a generalized Fibonacci sequence. In order to obtain the role of the deformation parameters (q1,q2) on the thermostatistics of the system, we calculate several thermostatistical functions in the thermodynamical limit and investigate the low-temperature behavior of the system. In this framework, we show that the thermostatistics of the (q1,q2)-bosons can be studied by the formalism of Fibonacci calculus which generalizes the recently proposed formalism of q-calculus. We also discuss the conditions under which the Bose-Einstein condensation would occur in the present two-parameter generalized boson gas. However, the ordinary boson gas results can be obtained by applying the limit q1=q2=1.

Abdullah Algin

2008-10-10

117

Nucleation and growth of Nb nanoclusters during plasma gas condensation  

SciTech Connect

Niobium nanoclusters were produced using a plasma gas condensation process. The influence of gas flow rate, aggregation length, and source current on the nanocluster nucleation and growth were analyzed. Nanoclusters with an average diameter from 4 nm to 10 nm were produced. Cluster size and concentration were tuned by controlling the process inputs. The effects of each parameter on the nucleation zone, growth length, and residence time was examined. The parameters do not affect the cluster formation and growth independently; their influence on cluster formation can be either cumulative or competing. Examining the nucleation and growth over a wide combination of parameters provided insight into their interactions and the impact on the growth process. These results provide the opportunity for a broader understanding into the nucleation and growth of nanoclusters and some insights into how process parameters interact during deposition. This knowledge will enhance the ability to create nanoclusters with desired size dispersions.

Bray, K. R.; Jiao, C. Q. [UES, Inc., 4401 Dayton-Xenia Rd, Dayton, Ohio 45432 (United States)] [UES, Inc., 4401 Dayton-Xenia Rd, Dayton, Ohio 45432 (United States); DeCerbo, J. N. [Air Force Research Laboratory, AFRL/RQQE, 1950 Fifth St., WPAFB, Ohio 45433 (United States)] [Air Force Research Laboratory, AFRL/RQQE, 1950 Fifth St., WPAFB, Ohio 45433 (United States)

2013-06-21

118

46 CFR 154.1848 - Inerting.  

Code of Federal Regulations, 2014 CFR

...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

119

ELECTRONIC STRUCTURE AND SPECTROSCOPY IN THE GAS AND CONDENSED PHASE: METHODOLOGY AND APPLICATIONS.  

E-print Network

ELECTRONIC STRUCTURE AND SPECTROSCOPY IN THE GAS AND CONDENSED PHASE: METHODOLOGY AND APPLICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 iii #12;3 Future work 96 3.1 Methodology

Krylov, Anna I.

120

Condensation  

NSDL National Science Digital Library

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

Kessler, James H.; Galvan, Patricia M.

2007-01-01

121

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

E-print Network

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

122

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

123

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

124

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

Microsoft Academic Search

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

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

2010-01-01

125

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

NASA Astrophysics Data System (ADS)

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

Gensterblum, Y.; Krooss, B. M.

2013-12-01

126

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

NASA Technical Reports Server (NTRS)

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

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

1999-01-01

127

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

128

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

129

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

NASA Technical Reports Server (NTRS)

A more exact one-dimensional condensation heat transfer model for insoluble gases was developed and compared with experimental data. Modifications to this model to accommodate soluble gas behavior were also accomplished, and the effects on gas front behavior demonstrated. Analytical models for condensation heat transfer are documented, and an optical method used for measuring gas concentration profiles is outlined. Experimental data is then presented and interpreted.

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

1976-01-01

130

AVO in North of Paria, Venezuela: Gas methane versus condensate reservoirs  

SciTech Connect

The gas fields of North of Paria, offshore eastern Venezuela, present a unique opportunity for amplitude variations with offset (AVO) characterization of reservoirs containing different fluids: gas-condensate, gas (methane) and water (brine). AVO studies for two of the wells in the area, one with gas-condensate and the other with gas (methane) saturated reservoirs, show interesting results. Water sands and a fluid contact (condensate-water) are present in one of these wells, thus providing a control point on brine-saturated properties. The reservoirs in the second well consist of sands highly saturated with methane. Clear differences in AVO response exist between hydrocarbon-saturated reservoirs and those containing brine. However, it is also interesting that subtle but noticeable differences can be interpreted between condensate-and methane-saturated sands. These differences are attributed to differences in both in-situ fluid density and compressibility, and rock frame properties.

Regueiro, J. [Univ. Simon Bolivar, Sartenejas (Venezuela)] [Univ. Simon Bolivar, Sartenejas (Venezuela); Pena, A. [Lagoven S.A., Caracas (Venezuela)] [Lagoven S.A., Caracas (Venezuela)

1996-07-01

131

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

132

Bose-Einstein condensation in a gas of sodium atoms  

Microsoft Academic Search

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

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

1995-01-01

133

Initiation of Water Hammer in a Steam\\/Water Pipe with a Non-Condensable Gas  

Microsoft Academic Search

The effect of a non-condensable gas on the initiation of water hammer in a condensing water-steam system has been investigated by extending Bjorge's work. Based on computational results, it is concluded that the pipe slope is the dominant parameter which affects the initiation of water hammer. The effective temperature difference in driving energy across the liquid interface was found to

Jiann-Lin Chen; Tzu-Chen Hung; S. Kong Wang; Bau-Shi Pei

134

Quasi-one-and quasi-two-dimensional perfect Bose gas: the second critical density and generalised condensation  

E-print Network

condensation Mathieu Beau and Valentin A. Zagrebnov Universit´e de la M´editerran´ee and Centre de Physique Th) In this letter we discuss a relevance of the 3D Perfect Bose gas (PBG) condensation in extremely elongated vessels for the study of anisotropic condensate coherence and the "quasi-condensate". To this end we

Boyer, Edmond

135

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

E-print Network

ICEBO2006, Shenzhen, China Heating technologies for energy efficiency Vol.III-1-5 Analysis of Heating Systems and Scale of Natural Gas-Condensing Water Boilers in Northern Zones Yuanyuan Wu Suilin Wang Shuyuan Pan Yongzheng Shi...

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

2006-01-01

136

Modeling metallic nanoparticle synthesis in a magnetron-based nanocluster source by gas condensation of a sputtered vapor  

SciTech Connect

Copper nanoparticles (NPs) were synthesized by inert-gas condensation of a sputtered metallic vapor using a dedicated commercial reactor. By controlling the time of residence of NPs in the carrier gas phase via the tuning of the collision path length, Cu NPs were produced. They exhibit various and well controlled diameters (3-10 nm) and a relatively narrow size dispersion. On the basis of these experimental results, a detailed modeling of NP nucleation and growth based on the classical nucleation theory was developed. It takes into account the peculiar geometry and thermal profile of the NP reactor. The simulated curves, calculated by a MATLAB program developed for that purpose, exhibit a good qualitative agreement with experiment. Moreover, they highlight the role of process parameters and the strong influence of the reactor temperature profile on the NP size distribution. In the future, such calculations could be used for the optimization of the NP source design in order to increase its efficiency and reproducibility.

Quesnel, E; Pauliac-Vaujour, E; Muffato, V [CEA-G/DRT/LITEN/DTNM, rue des Martyrs, 38054 Grenoble Cedex 9 (France)

2010-03-15

137

Noisy dynamics of a vortex in a partially Bose-Einstein condensed gas  

SciTech Connect

We study the dynamics of a straight vortex line in a partially Bose-Einstein condensed atomic gas. Using a variational approach to the stochastic field equation that describes the dynamics of the condensate at nonzero temperature, we derive the stochastic equations of motion for the position of the vortex core. Using these results, we calculate the time it takes the vortex to spiral out of the condensate. Due to the fact that we include thermal fluctuations in our description, this lifetime of the vortex is finite even if its initial position is in the center of the condensate.

Duine, R.A.; Stoof, H.T.C. [Institute for Theoretical Physics, University of Utrecht, Leuvenlaan 4, 3584 CE Utrecht (Netherlands); Leurs, B.W.A. [Instituut-Lorentz for Theoretical Physics, University of Leiden, Niels Bohrweg 2, 2333 CA Leiden (Netherlands)

2004-05-01

138

Condensate fraction of a two-dimensional attractive Fermi gas  

SciTech Connect

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

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

2007-07-15

139

Experimental and analytical study of the effects of noncondensable gas in a passive condenser system  

NASA Astrophysics Data System (ADS)

Passive Containment Cooling System (PCCS) of the Simplified Boiling Water Reactor (SBWR) is a passive condenser system which is designed to remove energy from the reactor containment during a postulated reactor accident. The presence of noncondensable gas in the vapor can greatly reduce the performance of condensers. Hence a detailed knowledge of the heat removal performance of the PCCS in the presence of noncondensable gas is crucial for the safety and design optimization of the SBWR. The purpose of the present study is the experimental and theoretical investigation of the effects of noncondensable gas in a passive condenser system. Condensation experiments were performed for a vertical tube submerged in water pool. The present experimental data provide a new database for complete condensation, cyclic venting and through flow modes of the passive condenser. Cyclic venting mode was simulated by a control volume analysis. Analysis results showed that venting period decreases with noncondensable gas fraction. It was found that inception of venting can occur before the condenser is fully filled with noncondensable gas. A boundary layer model was developed for the prediction of the film condensation with noncondensable gas in a vertical tube. Full set of the governing equations for the liquid film and vapor-gas mixture regions were solved. A heat and mass analogy model was also developed with a specific purpose for use in the thermal hydraulic system analysis code. In the vapor-gas mixture region, general momentum, heat and mass transport relations derived by analytic method were used with the consideration of surface suction effect. The predictions from the models were compared with the experimental data and the agreement was satisfactory. A mechanistic condensation correlation was developed based on the experimental data and the analysis results. It contains all the heat transfer components in its functional relationships. New correlation can provide accurate estimation of local condensation heat transfer coefficient for wide range of operating parameters. The assessment of wall condensation models in RELAP5 code was performed. Experimental conditions were simulated with RELAP5. Code simulation showed quite different results compared with data. Therefore, the condensation model in RELAP5 needs to be improved.

Oh, Seungmin

140

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

141

Field data test new holdup, pressure-loss calculations for gas, condensate pipelines  

Microsoft Academic Search

This second of three articles compares the performance of several pressure loss and holdup correlations, including those proposed in Part 1 (OGJ, Mar. 14, p. 55), against field data taken from three large-diameter gas and gas-condensate pipelines. The conclusion of this series continues these comparisons by presenting field data from two more pipelines.

A. Baker; K. Nielsen; A. Gabb

1988-01-01

142

A new fast technique for calculation of gas condensate well productivity by using pseudopressure method  

Microsoft Academic Search

This paper presents a new fast technique to obtain gas condensate well productivity without using simulator. The calculation uses a material balance model for reservoir depletion and Fevang and Whitson’s two phase pseudopressure function for well inflow performance. The two phase pseudopressure technique cannot be applied independently for well performance evaluation since it requires the well production gas-oil ratio (GOR)

M. Bonyadi; M. R. Rahimpour; F. Esmaeilzadeh

143

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

SciTech Connect

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

Lekov, Alex; Franco, Victor; Meyers, Steve

2010-05-14

144

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

145

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

146

Recovery of Water from Boiler Flue Gas Using Condensing Heat Exchangers  

SciTech Connect

Most of the water used in a thermoelectric power plant is used for cooling, and DOE has been focusing on possible techniques to reduce the amount of fresh water needed for cooling. DOE has also been placing emphasis on recovery of usable water from sources not generally considered, such as mine water, water produced from oil and gas extraction, and water contained in boiler flue gas. This report deals with development of condensing heat exchanger technology for recovering moisture from flue gas from coal-fired power plants. The report describes: (1) An expanded data base on water and acid condensation characteristics of condensing heat exchangers in coal-fired units. This data base was generated by performing slip stream tests at a power plant with high sulfur bituminous coal and a wet FGD scrubber and at a power plant firing high-moisture, low rank coals. (2) Data on typical concentrations of HCl, HNO{sub 3} and H{sub 2}SO{sub 4} in low temperature condensed flue gas moisture, and mercury capture efficiencies as functions of process conditions in power plant field tests. (3) Theoretical predictions for sulfuric acid concentrations on tube surfaces at temperatures above the water vapor dewpoint temperature and below the sulfuric acid dew point temperature. (4) Data on corrosion rates of candidate heat exchanger tube materials for the different regions of the heat exchanger system as functions of acid concentration and temperature. (5) Data on effectiveness of acid traps in reducing sulfuric acid concentrations in a heat exchanger tube bundle. (6) Condensed flue gas water treatment needs and costs. (7) Condensing heat exchanger designs and installed capital costs for full-scale applications, both for installation immediately downstream of an ESP or baghouse and for installation downstream of a wet SO{sub 2} scrubber. (8) Results of cost-benefit studies of condensing heat exchangers.

Edward Levy; Harun Bilirgen; John DuPoint

2011-03-31

147

Recovery of Water from Boiler Flue Gas Using Condensing Heat Exchangers  

SciTech Connect

Most of the water used in a thermoelectric power plant is used for cooling, and DOE has been focusing on possible techniques to reduce the amount of fresh water needed for cooling. DOE has also been placing emphasis on recovery of usable water from sources not generally considered, such as mine water, water produced from oil and gas extraction, and water contained in boiler flue gas. This report deals with development of condensing heat exchanger technology for recovering moisture from flue gas from coal-fired power plants. The report describes: • An expanded data base on water and acid condensation characteristics of condensing heat exchangers in coal-fired units. This data base was generated by performing slip stream tests at a power plant with high sulfur bituminous coal and a wet FGD scrubber and at a power plant firing highmoisture, low rank coals. • Data on typical concentrations of HCl, HNO{sub 3} and H{sub 2}SO{sub 4} in low temperature condensed flue gas moisture, and mercury capture efficiencies as functions of process conditions in power plant field tests. • Theoretical predictions for sulfuric acid concentrations on tube surfaces at temperatures above the water vapor dewpoint temperature and below the sulfuric acid dew point temperature. • Data on corrosion rates of candidate heat exchanger tube materials for the different regions of the heat exchanger system as functions of acid concentration and temperature. • Data on effectiveness of acid traps in reducing sulfuric acid concentrations in a heat exchanger tube bundle. • Condensed flue gas water treatment needs and costs. • Condensing heat exchanger designs and installed capital costs for full-scale applications, both for installation immediately downstream of an ESP or baghouse and for installation downstream of a wet SO{sub 2} scrubber. • Results of cost-benefit studies of condensing heat exchangers.

Levy, Edward; Bilirgen, Harun; DuPont, John

2011-03-31

148

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

E-print Network

1083 Exciton Bose condensation : the ground state of an electron-hole gas II. Spin states, incorporant la condensation de Bose des paires électron-trou. Nous étudions en détail la limite diluée, et incorporates Bose condensation of bound electron-hole pairs. We discuss in detail the low density limit

Boyer, Edmond

149

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

150

Factors affecting iron carbonate scale in gas condensate wells containing CO{sub 2}  

SciTech Connect

The conditions inside of gas condensate wells are typically not conducive to the formation of iron carbonate scale. The fact is that most of the natural inhibition in these wells is from the presence of this scale. Conditions under which this scale is not allowed to form, produce a highly corrosive condition which allows failures to occur in as little as 6 months. This paper attempts to provide a perspective into three of the primary factors inside gas condensate wells which allow or prevent this scale from forming.

Garber, J.D.; Sangita, K.A. [Univ. of Southwestern Louisiana, Lafayette, LA (United States). Corrosion Research Center

1998-12-31

151

On the retrograde condensation behavior of lean natural gas  

NASA Astrophysics Data System (ADS)

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

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

1995-05-01

152

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

153

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

154

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

155

Gas pressure on the surface of condensed phase in a resonance radiation field  

Microsoft Academic Search

The influence of resonance radiation on the pressure exerted by gas on the surface of a condensed phase is studied. The effects, which are associated with a change in the recoil pressure of molecules escaping from the surface in a radiation field, are considered. Combined manifestation of thermal and resonance effects is analyzed, as well as the influence of a

V. V. Levdansky

1999-01-01

156

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

E-print Network

and on the quantification of their impact on reservoir fluid flow and well performance. We selected three relative permeability models to compare the results obtained in the modeling of relative permeabilities for a published North Sea gas condensate reservoir. The models...

Zapata Arango, Jose? Francisco

2012-06-07

157

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

E-print Network

THE EFFECTS OF NON-CONDENSIBLE GAS AND SALINITY ON STEAM ADSORPTION A REPORT SUBMITTED% by weight of saline solution was added to the rock sample. Addition of salt to the sample enabled.1 Effects of GO2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.2 Effects of Salinity

Stanford University

158

Adapting gas-phase electron scattering R -matrix calculations to a condensed-matter environment  

Microsoft Academic Search

We investigate how gas phase R -matrix calculations for electron collisions with the water molecule can be efficiently used in a condensed environment. The electron band structure of cubic ice being fairly well studied, we try to reproduce it using a generalization of the Korringa-Kohn-Rostoker band calculation method. We find two cutoffs have to be applied to the R -matrix

Laurent Caron; D. Bouchiha; J. D. Gorfinkiel; L. Sanche

2007-01-01

159

Engineering design of gas-condensate pipelines with a compositional hydrodynamic model  

SciTech Connect

Gas condensation in pipelines designed to transport natural gas is common. The difference in the engineering design required for this system, compared with the required of dry gas pipelines, makes the problem of significant interest to the gas industry. Because the point and quantity of condensation is not usually known a priori, any attempt to develop a predictive capability for such a system must have an inherent means of providing this information. This requires a good coupling of the gas-phase behavior model with the appropriate hydrodynamic model. This paper reports work to develop such a model. With a two-parameter equation of state (EOS) to describe the phase behavior of the natural-gas system, a multiphase hydrodynamic model developed from fundamental fluid dynamics is used to describe the hydrodynamic behavior of the resulting two phases. The model, which consists of a system of nonlinear algebraic and ordinary differential equations (ODE's), was solved numerically. Output from the model solution includes quantity of condensation at any point in the pipeline, pressure drop, and other hydrodynamic variables. The model can predict the various engineering parameters of interest in the design of such pipelines and could be used for feasibility studies and for optimal location of fluid-handling equipment.

Vincent, P.A. (Trinidad Ministry of Energy (TT)); Adewumi, M.A. (Pennsylvania State Univ., University Park, PA (USA). Dept. of Petroleum and Natural Gas)

1990-11-01

160

Confined Phase Envelope of Gas-Condensate Systems in Shale Rocks  

NASA Astrophysics Data System (ADS)

Natural gas from shales (NGS) and from tight rocks are one of the most important fossil energy resource in this and next decade. Significant increase in gas consumption, in all world regions, will be marked in the energy sector. The exploration of unconventional natural gas & oil reservoirs has been discussed recently in many conferences. This paper describes the complex phenomena related to the impact of adsorption and capillary condensation of gas-condensate systems in nanopores. New two phase saturation model and new algorithm for search capillary condensation area is discussed. The algorithm is based on the Modified Tangent Plane Criterion for Capillary Condensation (MTPCCC) is presented. The examples of shift of phase envelopes are presented for selected composition of gas-condensate systems. Gaz ziemny z ?upków (NGS) oraz z ze z?ó? niskoprzepuszczalnych (typu `tight') staje si? jednym z najwa?niejszych zasobów paliw kopalnych, w tym i nast?pnym dziesi?cioleciu. Znacz?cy wzrost zu?ycia gazu we wszystkich regionach ?wiata zaznacza si? g?ównie w sektorze energetycznym. Rozpoznawanie niekonwencjonalnych z?ó? gazu ziemnego i ropy naftowej w ostatnim czasie jest omawiane w wielu konferencjach. Niniejszy artyku? opisuje z?o?one zjawiska zwi?zane z wp?ywem adsorpcji i kapilarnej kondensacji w nanoporach w z?o?ach gazowo-kondensatowych. Pokazano nowy dwufazowy model równowagowy dwufazowy i nowy algorytm wyznaczania krzywej nasycenia w obszarze kondensacji kapilarnej. Algorytm bazuje na kryterium zmodyfikowanym p?aszczyzny stycznej dla kapilarnej kondensacji (MTPCCC). Przyk?ady zmiany krzywych nasycenia s? przedstawiane w wybranym sk?adzie systemów gazowo- kondensatowych

Nagy, Stanislaw; Siemek, Jakub

2014-12-01

161

Application of the parallel multicanonical method to lattice gas condensation  

NASA Astrophysics Data System (ADS)

We present the speedup from a novel parallel implementation of the multicanonical method on the example of a lattice gas in two and three dimensions. In this approach, all cores perform independent equilibrium runs with identical weights, collecting their sampled histograms after each iteration in order to estimate consecutive weights. The weights are then redistributed to all cores. These steps are repeated until the weights are converged. This procedure benefits from a minimum of communication while distributing the necessary amount of statistics efficiently. Using this method allows us to study a broad temperature range for a variety of large and complex systems. Here, a gas is modeled as particles on the lattice, which interact only with their nearest neighbors. For a fixed density this model is equivalent to the Ising model with fixed magnetization. We compare our results to an analytic prediction for equilibrium droplet formation, confirming that a single macroscopic droplet forms only above a critical density.

Zierenberg, Johannes; Wiedenmann, Micha; Janke, Wolfhard

2014-05-01

162

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

163

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

SciTech Connect

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

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

2011-11-15

164

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

165

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

166

Terahertz Active Photonic Crystals for Condensed Gas Sensing  

PubMed Central

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

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

2011-01-01

167

Exciton Bose condensation : the ground state of an electron-hole gas I. Mean field description of a simplified model  

E-print Network

1069 Exciton Bose condensation : the ground state of an electron-hole gas I. Mean field description dégénérées. Nous étudions la condensation de Bose de ce système en fonction de la densité, négligeant dans the Bose condensed ground state of that system as a function of density, using a mean field variational

Boyer, Edmond

168

Condensation of supersaturated vapors. X. Pressure and nonideal gas effects  

NASA Astrophysics Data System (ADS)

Calculations of temperatures and supersaturations in nucleation experiments often include the assumption that all gases are ideal and they ignore the increase in vapor pressure due to the presence of noncondensible gases. Regardless of experimental technique, such assumptions can lead to substantial errors when comparing experiment to theory, especially when included in only one or the other. To demonstrate these effects, the procedures for calculating the temperatures and supersaturations in thermal diffusion cloud chambers are examined in detail. Nonideal gas effects do alter them; however, these effects also alter the rates calculated by nucleation theory and the effect is larger on nucleation theory than on the analysis of the experimental data. Due to the presence of noncondensible gases there also is a Poynting type effect, but it very nearly cancels in thermal diffusion cloud chambers when included consistently in both theory and experiment. An additional effect which arises only in nucleation theory is the nonzero compressibility of the critical nuclei. The net result (for n-nonane), when these effects are included consistently in both experiment and theory, is to reduce the temperature dependence of the multiplicative correction to theory necessary for agreement with experiment. None of these effects account for the previously observed apparent decrease in nucleation rate with increasing total pressure. Also critically examined are the uncertainties in the transport properties used to calculate the chamber profiles. Of particular interest is the uncertainty in the thermal diffusion factor which changes systematically with composition and thus with total pressure.

Fisk, Jeffery A.; Katz, Joseph L.

1996-06-01

169

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

Microsoft Academic Search

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

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

1995-01-01

170

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

Microsoft Academic Search

We find the universal structure and scaling of the Bose-Einstein condensation (BEC) statistics and thermodynamics (Gibbs free energy, average energy, heat capacity) for a mesoscopic canonical-ensemble ideal gas in a trap with an arbitrary number of atoms, any volume, and any temperature, including the whole critical region. We identify a universal constraint-cutoff mechanism that makes BEC fluctuations strongly non-Gaussian and

Vitaly V. Kocharovsky; Vladimir V. Kocharovsky

2010-01-01

171

Adapting gas-phase electron scattering R-matrix calculations to a condensed-matter environment  

Microsoft Academic Search

We investigate how gas phase R-matrix calculations for electron collisions with the water molecule can be efficiently used in a condensed environment. The electron band structure of cubic ice being fairly well studied, we try to reproduce it using a generalization of the Korringa-Kohn-Rostoker band calculation method. We find two cutoffs have to be applied to the R-matrix elastic scattering

Laurent Caron; D. Bouchiha; J. D. Gorfinkiel; L Sanche

2007-01-01

172

Condensed matter photoacoustic spectroscopy and detection using gas phase signal generation  

SciTech Connect

Photoacoustic (PA) spectroscopy and detection involving condensed samples and gas phase signal generation are briefly reviewed. Theoretical considerations, instrumentation, and applications are discussed with emphasis on electronic materials studies. Applications include PA absorption spectroscopy of single crystal CdS and ion implanted GaAs int he bandgap region, PA imaging of compositional variations related to thermal properties in H/sub gl-x/Cd/sub x/Te, and laser heating of Ge.

McClelland, J.F.

1980-01-01

173

Silicon clusters produced by femtosecond laser ablation: Non-thermal emission and gas-phase condensation  

E-print Network

Neutral silicon clusters Si_n (up to n = 7) and their cations Si_n+ (up to n = 10) have been produced by femtosecond laser ablation of bulk silicon in vacuum and investigated using time-of-flight mass spectrometry. Two populations of the Si_n+ clusters with different velocity and abundance distributions in the ablation plume have been clearly distinguished. Possible mechanisms of cluster formation (Coulomb explosion, gas-phase condensation, phase explosion) are discussed.

Bulgakov, A V; Ozerov, I; Bulgakov, Alexander V.; Ozerov, Igor; ccsd-00001265, ccsd

2004-01-01

174

Theory and Calculation of the Condensation Growth of a Droplet in Pure Vapor and in a Vapor–Gas Mixture  

Microsoft Academic Search

Consideration is given to the theory of condensation as applied to the liquefaction of gases. Numerical calculations of the growth of a droplet using methane as an example revealed the decisive role of heat removal from its surface to the ambient medium in condensation from both a pure vapor and a vapor–gas mixture. It is shown that for very low

K. M. Aref'ev; Yu. G. Belostotskii; A. M. Koshelev

2001-01-01

175

Local Observation of Pair Condensation in a Fermi Gas at Unitarity  

NASA Astrophysics Data System (ADS)

We present measurements of the local (homogeneous) density-density response function of a Fermi gas at unitarity using spatially resolved Bragg spectroscopy. By analyzing the Bragg response across one axis of the cloud, we extract the response function for a uniform gas which shows a clear signature of the Bose-Einstein condensation of pairs of fermions when the local temperature drops below the superfluid transition temperature. The method we use for local measurement generalizes a scheme for obtaining the local pressure in a harmonically trapped cloud from the line density and can be adapted to provide any homogeneous parameter satisfying the local density approximation.

Lingham, M. G.; Fenech, K.; Hoinka, S.; Vale, C. J.

2014-03-01

176

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

SciTech Connect

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

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

2011-09-15

177

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

178

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

179

Advances in SAW Gas Sensors Based on the Condensate-Adsorption Effect  

PubMed Central

A surface-acoustic-wave (SAW) gas sensor with a low detection limit and fast response for volatile organic compounds (VOCs) based on the condensate-adsorption effect detection is developed. In this sensor a gas chromatography (GC) column acts as the separator element and a dual-resonator oscillator acts as the detector element. Regarding the surface effective permittivity method, the response mechanism analysis, which relates the condensate-adsorption effect, is performed, leading to the sensor performance prediction prior to fabrication. New designs of SAW resonators, which act as feedback of the oscillator, are devised in order to decrease the insertion loss and to achieve single-mode control, resulting in superior frequency stability of the oscillator. Based on the new phase modulation approach, excellent short-term frequency stability (±3 Hz/s) is achieved with the SAW oscillator by using the 500 MHz dual-port resonator as feedback element. In a sensor experiment investigating formaldehyde detection, the implemented SAW gas sensor exhibits an excellent threshold detection limit as low as 0.38 pg. PMID:22247697

Liu, Jiuling; Wang, Wen; Li, Shunzhou; Liu, Minghua; He, Shitang

2011-01-01

180

Full field reservoir modelling of Central Oman gas/condensate fields  

SciTech Connect

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

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

1995-12-31

181

Laboratory Evaporation Testing Of Hanford Waste Treatment Plant Low Activity Waste Off-Gas Condensate Simulant  

SciTech Connect

The Hanford Waste Treatment and Immobilization Plant (WTP) Low Activity Waste (LAW) vitrification facility will generate an aqueous condensate recycle stream, LAW Off-Gas Condensate, from the off-gas system. The baseline plan for disposition of this stream is to send it to the WTP Pretreatment Facility, where it will be blended with LAW, concentrated by evaporation and recycled to the LAW vitrification facility again. Alternate disposition of this stream would eliminate recycling of problematic components, and would enable de-coupled operation of the LAW melter and the Pretreatment Facilities. Eliminating this stream from recycling within WTP would also decrease the LAW vitrification mission duration and quantity of canistered glass waste forms. This LAW Off-Gas Condensate stream contains components that are volatile at melter temperatures and are problematic for the glass waste form. Because this stream recycles within WTP, these components accumulate in the Condensate stream, exacerbating their impact on the number of LAW glass containers that must be produced. Approximately 32% of the sodium in Supplemental LAW comes from glass formers used to make the extra glass to dilute the halides to be within acceptable concentration ranges in the LAW glass. Diverting the stream reduces the halides in the recycled Condensate and is a key outcome of this work. Additionally, under possible scenarios where the LAW vitrification facility commences operation prior to the WTP Pretreatment facility, identifying a disposition path becomes vitally important. This task examines the impact of potential future disposition of this stream in the Hanford tank farms, and investigates auxiliary evaporation to enable another disposition path. Unless an auxiliary evaporator is used, returning the stream to the tank farms would require evaporation in the 242-A evaporator. This stream is expected to be unusual because it will be very high in corrosive species that are volatile in the melter (chloride, fluoride, sulfur), will have high ammonia, and will contain carryover particulates of glass-former chemicals. These species have potential to cause corrosion of tanks and equipment, precipitation of solids, release of ammonia gas vapors, and scale in the tank farm evaporator. Routing this stream to the tank farms does not permanently divert it from recycling into the WTP, only temporarily stores it prior to reprocessing. Testing is normally performed to demonstrate acceptable conditions and limits for these compounds in wastes sent to the tank farms. The primary parameter of this phase of the test program was measuring the formation of solids during evaporation in order to assess the compatibility of the stream with the evaporator and transfer and storage equipment. The origin of this LAW Off-Gas Condensate stream will be the liquids from the Submerged Bed Scrubber (SBS) and the Wet Electrostatic Precipitator (WESP) from the LAW facility melter offgas system. The stream is expected to be a dilute salt solution with near neutral pH, and will likely contain some insoluble solids from melter carryover. The soluble components are expected to be mostly sodium and ammonium salts of nitrate, chloride, and fluoride. This stream has not been generated yet, and, thus, the composition will not be available until the WTP begins operation, but a simulant has been produced based on models, calculations, and comparison with pilot-scale tests. This report discusses results of evaporation testing of the simulant. Two conditions were tested, one with the simulant at near neutral pH, and a second at alkaline pH. The neutral pH test is comparable to the conditions in the Hanford Effluent Treatment Facility (ETF) evaporator, although that evaporator operates at near atmospheric pressure and tests were done under vacuum. For the alkaline test, the target pH was based on the tank farm corrosion control program requirements, and the test protocol and equipment was comparable to that used for routine evaluation of feed compatibility studies for the 242-A evaporator. One of the

Adamson, Duane J.; Nash, Charles A.; McCabe, Daniel J.; Crawford, Charles L.; Wilmarth, William R.

2014-01-27

182

Condensed combustion products of aluminized propellants. 1. A technique for investigating the evolution of disperse-phase particles  

Microsoft Academic Search

This paper describes a technique for investigating the evolution of the condensed combustion products of metallized propellants. The technique involves freezing the combustion products of a propellant sample at different distances from the burning surface by mixing with a cocurrent cold flow of an inert diluent gas, followed by collecting the particles in metal sieves and in an aerosol filter.

O. G. Glotov; V. Ya. Zyryanov

1995-01-01

183

Renormalization Theory of a Two Dimensional Bose Gas: Quantum Critical Point and Quasi-Condensed State  

NASA Astrophysics Data System (ADS)

We present a renormalization group construction of a weakly interacting Bose gas at zero temperature in the two-dimensional continuum, both in the quantum critical regime and in the presence of a condensate fraction. The construction is performed within a rigorous renormalization group scheme, borrowed from the methods of constructive field theory, which allows us to derive explicit bounds on all the orders of renormalized perturbation theory. Our scheme allows us to construct the theory of the quantum critical point completely, both in the ultraviolet and in the infrared regimes, thus extending previous heuristic approaches to this phase. For the condensate phase, we solve completely the ultraviolet problem and we investigate in detail the infrared region, up to length scales of the order (? ^3? _0)^{-1/2} (here ? is the interaction strength and ? _0 the condensate density), which is the largest length scale at which the problem is perturbative in nature. We exhibit violations to the formal Ward Identities, due to the momentum cutoff used to regularize the theory, which suggest that previous proposals about the existence of a non-perturbative non-trivial fixed point for the infrared flow should be reconsidered.

Cenatiempo, S.; Giuliani, A.

2014-07-01

184

Classification of gasoline by octane number and light gas condensate fractions by origin with using dielectric or gas-chromatographic data and chemometrics tools  

Microsoft Academic Search

The approach for classification of gasoline by octane number and light gas condensate fractions by origin with using dielectric permeability data has been proposed and compared with classification of same samples on the basis of gas-chromatographic data. The precision of dielectric permeability measurements was investigated by using ANOVA. The relative standard deviation of dielectric permeability was in the range from

Vasiliy A. Rudnev; Alexander P. Boichenko; Pavel V. Karnozhytskiy

2011-01-01

185

Classification of gasoline by octane number and light gas condensate fractions by origin with using dielectric or gas-chromatographic data and chemometrics tools.  

PubMed

The approach for classification of gasoline by octane number and light gas condensate fractions by origin with using dielectric permeability data has been proposed and compared with classification of same samples on the basis of gas-chromatographic data. The precision of dielectric permeability measurements was investigated by using ANOVA. The relative standard deviation of dielectric permeability was in the range from 0.3 to 0.5% for the range of dielectric permeability from 1.8 to 4.4. The application of exploratory chemometrics tools (cluster analysis and principal component analysis) allow to explicitly differentiate the gasoline and light gas condensate fractions into groups of samples related to specific octane number or origin. The neural networks allow to perfectly classifying the gasoline and light gas condensate fractions. PMID:21482310

Rudnev, Vasiliy A; Boichenko, Alexander P; Karnozhytskiy, Pavel V

2011-05-15

186

Horizontal in-tube condensation in the presence of a noncondensable gas  

NASA Astrophysics Data System (ADS)

A horizontal heat exchanger design has been proposed for the Passive Containment Cooling System (PCCS) condenser of future Boiling Water Reactors (BWR). Compared to the vertical design, it has several advantages, but the challenge is that there is a lack of mechanistic understanding of the heat transfer and fluid flow phenomena occurring in the heat exchanger tubes. There is also the need for mechanistic analysis tools that can assess condenser performance. This research experimentally investigates the local heat transfer from the condensation of steam in the presence of noncondensable gas in a single horizontal tube. To capture the asymmetrical nature of horizontal two-phase flow and heat transfer, the heat fluxes at the top and bottom of the condenser tube were obtained. A novel thermocouple was designed and fabricated to accurately measure the inside wall temperature from which a local heat flux can be deduced. The calibration technique of the thermocouple pairs was also developed. This local heat flux measurement technique is an original method for data which had previously been unattainable. It is applicable to phase-change heat exchangers of any inclination. Tests with parameters that cover both design base accident and severe accident conditions have been performed. Analysis showed that the heat transfer at the top of the tube is much better than that at the bottom of the tube, which shows that for most of the conditions the liquid phase distribution has a great effect on the heat transfer. The effect of noncondensable gas has been qualitatively studied both locally and globally from the experimental data. A mechanistic model was developed independent of the experimental data and was verified by the experimental data. Diffusion layer theory was used to account for the effect of noncondensable gas. For annular flow, the phenomenon inside the tube was assumed to be symmetrical. For wavy and stratified flow, the tube is divided into top and bottom parts peripherally based on the local phase distribution. The heat transfer mode across the liquid film was considered differently for the top and bottom part of the tube. The predictions from the mechanistic model were compared with the experimental data both locally and globally, and the agreement was satisfactory.

Wu, Tiejun

187

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

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

188

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

SciTech Connect

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

Marcos Dantus

2008-09-23

189

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.

190

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

191

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

NASA Astrophysics Data System (ADS)

Based on the generalized uncertainty principle (GUP), the critical temperature and the Helmholtz free energy of Bose—Einstein condensation (BEC) in the relativistic ideal Bose gas are investigated. At the non-relativistic limit and the ultra-relativistic limit, we calculate the analytical form of the shifts of the critical temperature and the Helmholtz free energy caused by weak quantum gravitational effects. The exact numerical results of these shifts are obtained. Quantum gravity effects lift the critical temperature of BEC. By measuring the shift of the critical temperature, we can constrain the deformation parameter ?0. Furthermore, at lower densities, omitting quantum gravitational effects may lead to a metastable state while at sufficiently high densities, quantum gravitational effects tend to make BEC unstable. Using the numerical methods, the stable-unstable transition temperature is found.

Zhang, Xiu-Ming; Tian, Chi

2015-01-01

192

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

193

The potential for intrinsic bioremediation of BTEX hydrocarbons in soil\\/ground water contaminated with gas condensate  

Microsoft Academic Search

Gas condensate liquids contaminate soil and ground water at two gas production sites in the Denver Basin, CO. A detailed field\\u000a study was carried out at these sites to determine the applicability of intrinsic bioremediation as a remediation option. Ground\\u000a water monitoring at the field sites and analysis of soil cores suggested that intrinsic bioremediation is occurring at the\\u000a sites

Abhijeet P. Borole; Kerry L. Sublette; Kevin T. Raterman; Minoo Javanmardian; J. Berton Fisher

1997-01-01

194

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

E-print Network

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

Firoozabadi, Abbas

195

User's manual for the TRW gaspipe 2 program: A vapor-gas front analysis program for heat pipes containing non-condensible gas  

NASA Technical Reports Server (NTRS)

A digital computer program for design and analysis of heat pipes which contain non-condensible gases, either for temperature control or to aid in start-up from the frozen state, is presented. Some of the calculations which are possible with the program are: (1) wall temperature profile along a gas-loaded heat pipe, (2) amount of gas loading necessary to obtain desired evaporator temperature at a desired heat load, (3) heat load versus evaporator temperature for a fixed amount of gas in the pipe, and (4) heat and mass transfer along the pipe, including the vapor-gas front region.

Edwards, D. K.; Fleischman, G. L.; Marcus, B. D.

1973-01-01

196

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

SciTech Connect

A study was designed to determine if the intrinsic bioremediation of gas condensate hydrocarbons represented an important fate process in a shallow aquifer underlying a natural gas production site. For over 4 yr, changes in the groundwater, sediment, and vadose zone chemistry in the contaminated portion of the aquifer were interpreted relative to a background zone. Changes included decreased dissolved oxygen and sulfate levels and increased alkalinity, Fe(II), and methane concentrations in the contaminated groundwater, suggesting that aerobic heterotrophic respiration depleted oxygen reserves leaving anaerobic conditions in the hydrocarbon-impacted subsurface. Dissolved hydrogen levels in the contaminated groundwater indicated that sulfate reduction and methanogenesis were predominant biological processes, corroborating the geochemical findings. Furthermore, 10--1000-fold higher numbers of sulfate reducers and methanogens were enumerated in the contaminated sediment relative to background. Putative metabolites were also detected in the contaminated groundwater, including methylbenzylsuccinic acid, a signature intermediate of anaerobic xylene decay. Laboratory incubations showed that benzene, toluene, ethylbenzene, and each of the xylene isomers were biodegraded under sulfate-reducing conditions as was toluene under methanogenic conditions. These results coupled with a decrease in hydrocarbon concentrations in contaminated sediment confirm that intrinsic bioremediation contributes to the attenuation of hydrocarbons in this aquifer.

Gieg, L.M.; McInerney; Tanner, R.S.; Harris, S.H. Jr.; Sublette, K.L.; Suflita, J.M. (Univ. of Oklahoma, Norman, OK (United States)); Kolhatkar, R.V. (Univ. of Tulsa, OK (United States). Center for Environmental Research and Technology)

1999-08-01

197

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

NASA Astrophysics Data System (ADS)

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

Kocharovsky, Vitaly V.; Kocharovsky, Vladimir V.

2010-03-01

198

LABORATORY OPTIMIZATION TESTS OF TECHNETIUM DECONTAMINATION OF HANFORD WASTE TREATMENT PLANT LOW ACTIVITY WASTE OFF-GAS CONDENSATE SIMULANT  

SciTech Connect

The Hanford Waste Treatment and Immobilization Plant (WTP) Low Activity Waste (LAW) vitrification facility will generate an aqueous condensate recycle stream (LAW Off-Gas Condensate) from the off-gas system. The baseline plan for disposition of this stream is to send it to the WTP Pretreatment Facility, where it will be blended with LAW, concentrated by evaporation and recycled to the LAW vitrification facility again. Alternate disposition of this stream would eliminate recycling of problematic components, and would enable de-coupled operation of the LAW melter and the Pretreatment Facilities. Eliminating this stream from recycling within WTP would also decrease the LAW vitrification mission duration and quantity of glass waste. This LAW Off-Gas Condensate stream contains components that are volatile at melter temperatures and are problematic for the glass waste form. Because this stream recycles within WTP, these components accumulate in the Condensate stream, exacerbating their impact on the number of LAW glass containers that must be produced. Approximately 32% of the sodium in Supplemental LAW comes from glass formers used to make the extra glass to dilute the halides to acceptable concentrations in the LAW glass, and diverting the stream reduces the halides in the recycled Condensate and is a key outcome of this work. Additionally, under possible scenarios where the LAW vitrification facility commences operation prior to the WTP Pretreatment facility, identifying a disposition path becomes vitally important. This task examines the potential treatment of this stream to remove radionuclides and subsequently disposition the decontaminated stream elsewhere, such as the Effluent Treatment Facility (ETF), for example. The treatment process envisioned is very similar to that used for the Actinide Removal Process (ARP) that has been operating for years at the Savannah River Site (SRS), and focuses on using mature radionuclide removal technologies that are also compatible with longterm tank storage and immobilization methods. For this new application, testing is needed to demonstrate acceptable treatment sorbents and precipitating agents and measure decontamination factors for additional radionuclides in this unique waste stream. The origin of this LAW Off-Gas Condensate stream will be the liquids from the Submerged Bed Scrubber (SBS) and the Wet Electrostatic Precipitator (WESP) from the LAW melter off-gas system. The stream is expected to be a dilute salt solution with near neutral pH, and will likely contain some insoluble solids from melter carryover. The soluble components are expected to be mostly sodium and ammonium salts of nitrate, chloride, and fluoride. This stream has not been generated yet and will not be available until the WTP begins operation, but a simulant has been produced based on models, calculations, and comparison with pilot-scale tests. One of the radionuclides that is volatile and expected to be in greatest abundance in this LAW Off-Gas Condensate stream is Technetium-99 ({sup 99}Tc). Technetium will not be removed from the aqueous waste in the Hanford WTP, and will primarily end up immobilized in the LAW glass by repeated recycle of the off-gas condensate into the LAW melter. Other radionuclides that are low but are also expected to be in measurable concentration in the LAW Off-Gas Condensate are {sup 129}I, {sup 90}Sr, {sup 137}Cs, {sup 241}Pu, and {sup 241}Am. These are present due to their partial volatility and some entrainment in the off-gas system. This report discusses results of optimized {sup 99}Tc decontamination testing of the simulant. Testing examined use of inorganic reducing agents for {sup 99}Tc. Testing focused on minimizing the quantity of sorbents/reactants added, and minimizing mixing time to reach the decontamination targets in this simulant formulation. Stannous chloride and ferrous sulfate were tested as reducing agents to determine the minimum needed to convert soluble pertechnetate to the insoluble technetium dioxide. The reducing agents were tried with and without sorbents.

Taylor-Pashow, K.; Nash, C.; McCabe, D.

2014-09-29

199

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

200

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

SciTech Connect

After 2 years of operation, a condensate recycle line at a natural gas production field failed due to fatigue cracking. Fatigue was caused by a combination of both cyclic stresses related to an intermittant operational mode and stress concentration at the base of a fillet weld. Stress concentration was increased by weld surface defects, including undercut and overlap, that produced a sharp transition at the fillet weld base. Internal welding defects, such as porosity and lack of fusion, did not play a role in crack formation. On the other hand, the failure could be assisted by corrosion after exposing the crack surface to the atmospheric condition. The problem was solved by improving the geometry of the fillet weld so that acceptable contouring with a smooth transition at fillet weld base was obtained, reducing the stress concentration. Periodic inspection was scheduled to detect the existence of outer surface cracks and determine the necessary action to be done in order to avoid sudden failure and unexpected shut down.

El-Batahgy, A. [Welding Research Department, Central Metallurgical R and D Institute, Cairo (Egypt)]. E-mail: elbatahgy@yahoo.com; Zaghloul, B. [Central Metallurgical R and D Institute, Cairo (Egypt)

2005-03-15

201

Modeling of the dynamics of a gas phase evaporating from the surface of a condensed phase under the effect of concentrated radiation pulses  

Microsoft Academic Search

An algorithm is developed which describes changes with time of the gas phase pressure near the condensate-gas interface due to the effect of concentrated radiation pulses. In the simplest case of a gas transparent to radiation, theoretical results are shown to be in qualitative agreement with experimental data.

P. V. Gerasimenko; V. A. Mazarchenkov; A. D. Suprun; A. M. Fedorchenko

1986-01-01

202

Photochemical activity of Titan's low-altitude condensed haze.  

PubMed

Titan, the largest moon of Saturn and similar to Earth in many aspects, has unique orange-yellow colour that comes from its atmospheric haze, whose formation and dynamics are far from well understood. Present models assume that Titan's tholin-like haze formation occurs high in atmosphere through gas-phase chemical reactions initiated by high-energy solar radiation. Here we address an important question: Is the lower atmosphere of Titan photochemically active or inert? We demonstrate that indeed tholin-like haze formation could occur on condensed aerosols throughout the atmospheric column of Titan. Detected in Titan's atmosphere, dicyanoacetylene (C?N?) is used in our laboratory simulations as a model system for other larger unsaturated condensing compounds. We show that C4N2 ices undergo condensed-phase photopolymerization (tholin formation) at wavelengths as long as 355 nm pertinent to solar radiation reaching a large portion of Titan's atmosphere, almost close to the surface. PMID:23552063

Gudipati, Murthy S; Jacovi, Ronen; Couturier-Tamburelli, Isabelle; Lignell, Antti; Allen, Mark

2013-01-01

203

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

NASA Astrophysics Data System (ADS)

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

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

2007-09-01

204

-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

205

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

SciTech Connect

Ferromagnetic SmCo{sub 5} nanoparticles with large size have been directly synthesized by a magnetron-sputtering-based gas-phase condensation method. Based on this method, we studied the effect of thermodynamic environment for the growth of SmCo{sub 5} nanoparticles. It was found that the well-crystallized SmCo{sub 5} nanoparticle tends to form a hexagonal disk shape with its easy axis perpendicular to the disk plane. More importantly, under the condition of high sputtering current, well-crystallized nanoparticles were found to be formed through a three-stage growth process: aggregation, coalescence, and second crystallization.

He Shihai; Jing Ying; Wang Jianping [Department of Electrical and Computer Engineering and Center for Micromagnetics and Information Technology (MINT), University of Minnesota, 200 Union St. SE, 4-174 EE/CSci, Minneapolis, Minnesota 55455 (United States)

2013-04-07

206

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

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

207

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

SciTech Connect

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

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

2009-09-01

208

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

SciTech Connect

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

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

1995-12-31

209

Cloud Condensation in Titan's Lower Stratosphere  

NASA Technical Reports Server (NTRS)

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

Romani, Paul N.; Anderson, Carrie M.

2011-01-01

210

Laboratory Scoping Tests Of Decontamination Of Hanford Waste Treatment Plant Low Activity Waste Off-Gas Condensate Simulant  

SciTech Connect

The Hanford Waste Treatment and Immobilization Plant (WTP) Low Activity Waste (LAW) vitrification facility will generate an aqueous condensate recycle stream (LAW Off-Gas Condensate) from the off-gas system. The baseline plan for disposition of this stream is to send it to the WTP Pretreatment Facility, where it will be blended with LAW, concentrated by evaporation and recycled to the LAW vitrification facility again. Alternate disposition of this stream would eliminate recycling of problematic components, and would enable de-coupled operation of the LAW melter and the Pretreatment Facilities. Eliminating this stream from recycling within WTP would also decrease the LAW vitrification mission duration and quantity of glass waste. This LAW Off-Gas Condensate stream contains components that are volatile at melter temperatures and are problematic for the glass waste form. Because this stream recycles within WTP, these components accumulate in the Condensate stream, exacerbating their impact on the number of LAW glass containers that must be produced. Approximately 32% of the sodium in Supplemental LAW comes from glass formers used to make the extra glass to dilute the halides to acceptable concentrations in the LAW glass, and diverting the stream reduces the halides in the recycled Condensate and is a key outcome of this work. Additionally, under possible scenarios where the LAW vitrification facility commences operation prior to the WTP Pretreatment facility, identifying a disposition path becomes vitally important. This task seeks to examine the potential treatment of this stream to remove radionuclides and subsequently disposition the decontaminated stream elsewhere, such as the Effluent Treatment Facility (ETF), for example. The treatment process envisioned is very similar to that used for the Actinide Removal Process (ARP) that has been operating for years at the Savannah River Site (SRS), and focuses on using mature radionuclide removal technologies that are also compatible with longterm tank storage and immobilization methods. For this new application, testing is needed to demonstrate acceptable treatment sorbents and precipitating agents and measure decontamination factors for additional radionuclides in this unique waste stream. The origin of this LAW Off-Gas Condensate stream will be the liquids from the Submerged Bed Scrubber (SBS) and the Wet Electrostatic Precipitator (WESP) from the LAW melter off-gas system. The stream is expected to be a dilute salt solution with near neutral pH, and will likely contain some insoluble solids from melter carryover. The soluble components are expected to be mostly sodium and ammonium salts of nitrate, chloride, and fluoride. This stream has not been generated yet and will not be available until the WTP begins operation, but a simulant has been produced based on models, calculations, and comparison with pilot-scale tests. One of the radionuclides that is volatile and expected to be in high concentration in this LAW Off-Gas Condensate stream is Technetium-99 ({sup 99}Tc). Technetium will not be removed from the aqueous waste in the Hanford WTP, and will primarily end up immobilized in the LAW glass by repeated recycle of the off-gas condensate into the LAW melter. Other radionuclides that are also expected to be in appreciable concentration in the LAW Off-Gas Condensate are {sup 129}I, {sup 90}Sr, {sup 137}Cs, and {sup 241}Am. This report discusses results of preliminary radionuclide decontamination testing of the simulant. Testing examined use of Monosodium Titanate (MST) to remove {sup 90}Sr and actinides, inorganic reducing agents for {sup 99}Tc, and zeolites for {sup 137}Cs. Test results indicate that excellent removal of {sup 99}Tc was achieved using Sn(II)Cl{sub 2} as a reductant, coupled with sorption onto hydroxyapatite, even in the presence of air and at room temperature. This process was very effective at neutral pH, with a Decontamination Factor (DF) >577 in two hours. It was less effective at alkaline pH. Conversely, removal of the cesium was more effective at alka

Taylor-Pashow, Kathryn M.; Nash, Charles A.; Crawford, Charles L.; McCabe, Daniel J.; Wilmarth, William R.

2014-01-21

211

Condensed tannin in drinking water reduces greenhouse gas precursor urea in sheep and cattle urine  

Technology Transfer Automated Retrieval System (TEKTRAN)

Ingestion of small amounts of naturally-occurring condensed tannin (CT) by ruminants can provide several benefits including potential reduction of ammonia and nitrous oxide emissions over the long-term by reducing their urine urea excretion. However, providing grazing ruminants with sufficient amou...

212

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

213

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

SciTech Connect

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

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

1993-04-01

214

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

PubMed Central

Carbonaceous presolar grains of supernovae origin have long been isolated and are determined to be the carrier of anomalous 22Ne in ancient meteorites. That exotic 22Ne is, in fact, the decay isotope of relatively short-lived 22Na formed by explosive nucleosynthesis, and therefore, a selective and rapid Na physical trapping mechanism must take place during carbon condensation in supernova ejecta. Elucidation of the processes that trap Na and produce large carbon molecules should yield insight into carbon stardust enrichment and formation. Herein, we demonstrate that Na effectively nucleates formation of Na@C60 and other metallofullerenes during carbon condensation under highly energetic conditions in oxygen- and hydrogen-rich environments. Thus, fundamental carbon chemistry that leads to trapping of Na is revealed, and should be directly applicable to gas-phase chemistry involving stellar environments, such as supernova ejecta. The results indicate that, in addition to empty fullerenes, metallofullerenes should be constituents of stellar/circumstellar and interstellar space. In addition, gas-phase reactions of fullerenes with polycyclic aromatic hydrocarbons are investigated to probe “build-up” and formation of carbon stardust, and provide insight into fullerene astrochemistry. PMID:24145444

Dunk, Paul W.; Adjizian, Jean-Joseph; Kaiser, Nathan K.; Quinn, John P.; Blakney, Gregory T.; Ewels, Christopher P.; Marshall, Alan G.; Kroto, Harold W.

2013-01-01

215

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

PubMed

Carbonaceous presolar grains of supernovae origin have long been isolated and are determined to be the carrier of anomalous (22)Ne in ancient meteorites. That exotic (22)Ne is, in fact, the decay isotope of relatively short-lived (22)Na formed by explosive nucleosynthesis, and therefore, a selective and rapid Na physical trapping mechanism must take place during carbon condensation in supernova ejecta. Elucidation of the processes that trap Na and produce large carbon molecules should yield insight into carbon stardust enrichment and formation. Herein, we demonstrate that Na effectively nucleates formation of Na@C60 and other metallofullerenes during carbon condensation under highly energetic conditions in oxygen- and hydrogen-rich environments. Thus, fundamental carbon chemistry that leads to trapping of Na is revealed, and should be directly applicable to gas-phase chemistry involving stellar environments, such as supernova ejecta. The results indicate that, in addition to empty fullerenes, metallofullerenes should be constituents of stellar/circumstellar and interstellar space. In addition, gas-phase reactions of fullerenes with polycyclic aromatic hydrocarbons are investigated to probe "build-up" and formation of carbon stardust, and provide insight into fullerene astrochemistry. PMID:24145444

Dunk, Paul W; Adjizian, Jean-Joseph; Kaiser, Nathan K; Quinn, John P; Blakney, Gregory T; Ewels, Christopher P; Marshall, Alan G; Kroto, Harold W

2013-11-01

216

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

217

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

218

Method for removing metal vapor from gas streams  

DOEpatents

A process for cleaning an inert gas contaminated with a metallic vapor, such as cadmium, involves withdrawing gas containing the metallic contaminant from a gas atmosphere of high purity argon; passing the gas containing the metallic contaminant to a mass transfer unit having a plurality of hot gas channels separated by a plurality of coolant gas channels; cooling the contaminated gas as it flows upward through the mass transfer unit to cause contaminated gas vapor to condense on the gas channel walls; regenerating the gas channels of the mass transfer unit; and, returning the cleaned gas to the gas atmosphere of high purity argon. The condensing of the contaminant-containing vapor occurs while suppressing contaminant particulate formation, and is promoted by providing a sufficient amount of surface area in the mass transfer unit to cause the vapor to condense and relieve supersaturation buildup such that contaminant particulates are not formed. Condensation of the contaminant is prevented on supply and return lines in which the contaminant containing gas is withdrawn and returned from and to the electrorefiner and mass transfer unit by heating and insulating the supply and return lines.

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

1996-01-01

219

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

NASA Astrophysics Data System (ADS)

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

Gao, Lin

220

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

NASA Technical Reports Server (NTRS)

A short description of the program Stardust whose goal is to study the formation and properties of high temperature particles and gases, including silicate and carbonaceous materials, that are of interest in astrophysics and planetary science, is given. The international program was carried out in microgravity conditions in parabolic flight. A description of the laboratory equipment, conceived to perform experimental tests in reduced gravity conditions, and which is based on the gas evaporation technique, is given. The gas evaporation technique utilizes one or more heated crucible to vaporize solids materials (SiO, Mg) in a low pressure of inert or reactive gas inside of a vacuum bell jar. The vapor pressures of the materials are controlled by the temperature of the crucibles. The temperature and pressure of inert gas are also controlled. By varying the vapor pressure relative to the gas temperature and pressure, the conditions for substantial grain condensation can be controlled and grain formation measured using light scattering techniques. Thus the partial pressure for grain condensation, can be measured as a function of temperature. The gas evaporation technique has the advantage that complex chemical systems can be studied by using multiple crucibles each containing solid source material. Experimental results and future trends are addressed.

Ferguson, F.; Lilleleht, L. U.; Nuth, J.; Stephens, J. R.; Bussoletti, E.; Carotenuto, L.; Colangeli, L.; Dellaversana, P.; Mele, F.; Mennella, V.

1992-01-01

221

Biofilter application for control of BTEX compounds from glycol dehydrator condenser vent gases at oil and natural gas producing facility  

SciTech Connect

Compliance with 1990 Clean Air Act Amendments will require cost-effective control technologies to reduce air emissions for petroleum industries. EPA has also proposed a new MACT Rule for Oil and Natural Gas Producing Facilities which will require control of emissions from glycol dehydrator vents. Control of volatile organic compound (VOC) emissions such as benzene, toluene, ethylbenzene, and xylene (BTEX) is one of the major concerns for the petroleum industries. Traditional VOC control methods may not be economically feasible to meet the requirements of these regulations. Recent studies have shown that biofilters can cost-effectively remove BTEX compounds with greater than 95% efficiency. This paper describes results from field testing a biofilter at an Oil and Natural Gas Producing facility. The biofilter treats a low flow gas stream containing high concentrations of VOCs and carbon dioxide from a glycol dehydrator condenser vent. A modular high-rate vapor phase biofilter developed by BioiReaction Industries was used to investigate the feasibility of this low-cost technology. Due to the high VOC loading (BTEX compounds up to 18,000 ppm; total VOCs 50,000 to 90,000 ppm), three modular biofilters were installed in series.

Stewart, W.C. [BioiReaction Industries, Inc., Tualatin, OR (United States); Kamarthi, R.S. [Texaco E and P Technology Dept., Bellaire, TX (United States)

1997-12-31

222

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

PubMed

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

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

2013-05-01

223

Effect of scenedesmus acuminatus green algae extracts on the development of Candida lipolytic yeast in gas condensate-containing media  

NASA Technical Reports Server (NTRS)

Data are given of a comparative study of the growth and development as well as the characteristics of the biomass of the C. Lipolytica yeast according to the content of raw protein, protein, lipids, vitamins in the B group, and residual hydrocarbons during growth in media with de-aromatized gas-condensate FNZ as the carbon source with aqueous and alcohol extracts of S. acuminatus as the biostimulants. It is shown that the decoction and aqueous extract of green algae has the most intensive stimulating effect on the yeast growth. When a decoction of algae is added to the medium, the content of residual hydrocarbons in the biomass of C. lipolytica yeast is reduced by 4%; the quantity of protein, lipids, thamine and inositol with replacement of the yeast autolysate by the decoction of algae is altered little.

Bilmes, B. I.; Kasymova, G. A.; Runov, V. I.; Karavayeva, N. N.

1980-01-01

224

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

SciTech Connect

Well control and completion operations were seriously complicated by an unusual pressure phenomena encountered while drilling an appraisal well through Jurassic sandstones in a high-pressure, high-temperature (HPHT), gas and condensate field located in the United Kingdom continental shelf. The HPHT sandstone reservoir is located in the Upper Jurassic Franklin formation. Unorthodox well-control techniques were used because it was determined that the abnormally high pressure was generated by a mechanical reaction of the rock under the effect of heavy mud and equivalent circulating density, rather than by entry into the wellbore of formation fluids. This paper reviews the complex drilling fluid control procedures which had to be utilized to maintain an open bore hole during drilling.

Idelovici, J.L.

1993-07-01

225

Dynamics and Evolution of SO2 Gas Condensation Around Prometheus-like Volcanic Plumes on Io as Seen by the Near Infrared Mapping Spectrometer  

NASA Technical Reports Server (NTRS)

Near Infrared Mapping Spectrometer data acquired during the I24, 25, and 27 Io's Fly-bys by Galileo are analyzed to map the SO2 frost abundance and granularity. This allows a better understanding of the dynamics and evolution of gas condensation around volcanic plumes. Additional information is contained in the original extended abstract.

Doute, S.; Lopes-Gautier, R.; Smythe, W. D.; Kamp, L. W.; Carlson, R.

2001-01-01

226

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

NASA Astrophysics Data System (ADS)

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

Alzetto, F.; Leyronas, X.

2010-04-01

227

A compact setup to study homogeneous nucleation and condensation  

NASA Astrophysics Data System (ADS)

An experiment is presented to study homogeneous nucleation and the subsequent droplet growth at high temperatures and high pressures in a compact setup that does not use moving parts. Nucleation and condensation are induced in an adiabatic, stationary expansion of the vapor and an inert carrier gas through a Laval nozzle. The adiabatic expansion is driven against atmospheric pressure by pressurized inert gas its mass flow carefully controlled. This allows us to avoid large pumps or vacuum storage tanks. Because we eventually want to study the homogeneous nucleation and condensation of zinc, the use of carefully chosen materials is required that can withstand pressures of up to 106 Pa resulting from mass flow rates of up to 600 lN min-1 and temperatures up to 1200 K in the presence of highly corrosive zinc vapor. To observe the formation of droplets a laser beam propagates along the axis of the nozzle and the light scattered by the droplets is detected perpendicularly to the nozzle axis. An ICCD camera allows to record the scattered light through fused silica windows in the diverging part of the nozzle spatially resolved and to detect nucleation and condensation coherently in a single exposure. For the data analysis, a model is needed to describe the isentropic core part of the flow along the nozzle axis. The model must incorporate the laws of fluid dynamics, the nucleation and condensation process, and has to predict the size distribution of the particles created (PSD) at every position along the nozzle axis. Assuming Rayleigh scattering, the intensity of the scattered light can then be calculated from the second moment of the PSD.

Karlsson, Mattias; Alxneit, Ivo; Rütten, Frederik; Wuillemin, Daniel; Tschudi, Hans Rudolf

2007-03-01

228

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

SciTech Connect

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

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

2012-11-15

229

AN INNOVATIVE TRANSPORT MEMBRANE CONDENSER FOR WATER RECOVERY FROM GAS AND ITS REUSE - PHASE I  

EPA Science Inventory

Although water recycle and reuse is considered good environmental practice, its implementation is highly dependent on the economics and hence can be challenging to implement. In this project, we present a unique opportunity to recover both water and energy from boiler flue gas...

230

Properties of a classical electron gas at the surface of condensed media  

Microsoft Academic Search

An analysis is made of the problem of the density distribution of a classical electron gas in a charged capacitor whose electrodes\\u000a are coated with dielectric films (liquid or solid). At high density the electrons form thin layers at each of the capacitor\\u000a electrodes. The electric field distribution is determined both inside and outside these layers.

A. M. Dyugaev; P. D. Grigor’ev; Yu. N. Ovchinnikov

2000-01-01

231

Self-similar analytical solution of the critical fluctuations problem for the Bose-Einstein condensation in an ideal gas  

NASA Astrophysics Data System (ADS)

An exact analytical solution for the universal probability distribution of the order parameter fluctuations as well as for the universal statistical and thermodynamic functions of an ideal gas in the whole critical region of Bose-Einstein condensation (BEC) is obtained. A universal constraint nonlinearity is found that is responsible for all nontrivial critical phenomena of the BEC phase transition. Simple analytical approximations, which describe the universal structure of the critical region in terms of confluent hypergeometric or parabolic cylinder functions, as well as asymptotics of the exact solution are derived. The results for the order parameter, all higher order moments of BEC fluctuations and thermodynamic quantities, including specific heat, perfectly match the known asymptotics outside critical region as well as the phenomenological renormalization-group ansatz with known critical exponents in the close vicinity of the critical point. Thus, a full analytical solution to a long-standing problem of finding a universal structure of the ? point for BEC in an ideal gas is found.

Kocharovsky, Vitaly V.; Kocharovsky, Vladimir V.

2010-06-01

232

Electrolyte vapor condenser  

DOEpatents

A system is disclosed for removing electrolyte from a fuel cell gas stream. The gas stream containing electrolyte vapor is supercooled utilizing conventional heat exchangers and the thus supercooled gas stream is passed over high surface area passive condensers. The condensed electrolyte is then drained from the condenser and the remainder of the gas stream passed on. The system is particularly useful for electrolytes such as phosphoric acid and molten carbonate, but can be used for other electrolyte cells and simple vapor separation as well.

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

1983-01-01

233

Electrolyte vapor condenser  

DOEpatents

A system is disclosed for removing electrolyte from a fuel cell gas stream. The gas stream containing electrolyte vapor is supercooled utilizing conventional heat exchangers and the thus supercooled gas stream is passed over high surface area passive condensers. The condensed electrolyte is then drained from the condenser and the remainder of the gas stream passed on. The system is particularly useful for electrolytes such as phosphoric acid and molten carbonate, but can be used for other electrolyte cells and simple vapor separation as well. 3 figs.

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

1983-02-08

234

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

235

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

236

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

237

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

238

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

Microsoft Academic Search

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

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

239

Bond and site selectivity in dissociative electron attachment to gas phase and condensed phase ethanol and trifluoroethanol.  

PubMed

The formation of negative ions following electron impact to ethanol (CH(3)CH(2)OH) and trifluoroethanol (CF(3)CH(2)OH) is studied in the gas phase by means of a crossed electron-molecular beam experiment and in the condensed phase via Electron Stimulated Desorption (ESD) of fragment ions from the corresponding molecular films under UHV conditions. Gas phase ethanol exhibits two pronounced resonances, located at 5.5 eV and 8.2 eV, associated with a remarkable selectivity in the decomposition of the precursor ion. While the low energy resonance exclusively decomposes into O(-), that at higher energy generates OH(-) and a comparatively small signal of [CH(3)CH(2)O](-) due to the loss of a neutral hydrogen. CF(3)CH(2)OH shows a completely different behaviour, as now an intense feature at 1.7 eV appears associated with the loss of a neutral hydrogen atom exclusively occurring at the O site. The H(-) formation from the gas phase compounds is below the detection limit of the present experiment, while in ESD from 3 MonoLayer (ML) films of CH(3)CH(2)OH and CF(3)CH(2)OH the most intense fragment is H(-), appearing from a broad resonant feature between 7 and 12 eV. With CF(3)CH(2)OH, by using the isotopically-labelled analogues CF(3)CD(2)OH and CF(3)CH(2)OD it can be shown that this feature consists of two resonances, one located at 8 eV leading to H(-)/D(-) loss from the O site and a second resonance located at 10 eV leading to the loss of H(-)/D(-) from the CH(2) site. PMID:17664966

Orzol, Mario; Martin, Isabel; Kocisek, Jaroslav; Dabkowska, Iwona; Langer, Judith; Illenberger, Eugen

2007-07-14

240

Measurement of reactive and condensable gas permeation using a mass spectrometer  

SciTech Connect

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

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

2008-09-15

241

Nanostructured metals produced by physical vapour deposition or structural and gas-reactive applications  

Microsoft Academic Search

This paper highlights some of the research being conducted at the Naval Research Laboratory on nanostructured materials synthesized by the inert-gas condensation method. This research effort was initially concentrated on the development of metal-based nanocomposites for high-temperature structural applications. The nanocomposite approach, used in this initial phase, was based on a strengthening concept that involved the use of nearly immiscible

V. Provenzano; R. L. Holtz

1997-01-01

242

Agglomeration of Ni-nanoparticles in the gas phase under gravity and microgravity conditions  

Microsoft Academic Search

The agglomeration of metallic nanoparticles can be performed using the well-known inert gas condensation process. Unfortunately, thermal effects such as convection are created by the heating source and as a result the turbulent aerosol avoids ideal conditions. In addition, the sedimentation of large particles and\\/or agglomerates influences the self-assembly of particles. These negative effects can be eliminated by using microgravity

S Lösch; G N Iles; B Schmitz; B H Günther

2011-01-01

243

A NEW EXPERIMENTAL CORRELATION USING A CURVE-SHAPED CAPACITANCE SENSOR TO PREDICT LIQUID HOLDUP IN VERTICAL GAS-CONDENSATE PIPELINES  

Microsoft Academic Search

The performance of a curve-shaped capacitance sensor for measuring the mean liquid holdup of the two-phase mixture of gas-condensate and nitrogen in a vertical pipeline was studied experimentally. The sensor consists of two electrodes placed on the external wall of a cylindrical test duct. The calibration curves for bubble, slug, and plug flow regimes were developed for vertical flow and

F. Esmaielzadeh; M. M. Izady; H. Moazzen J

2007-01-01

244

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

245

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

246

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

247

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

248

7 CFR 201.51 - Inert matter.  

Code of Federal Regulations, 2014 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,...

2014-01-01

249

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

250

DNA condensation  

Microsoft Academic Search

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

Victor A Bloomfield

1996-01-01

251

Kinetic boundary layers in gas mixtures: Systems described by nonlinearly coupled kinetic and hydrodynamic equations and applications to droplet condensation and evaporation  

SciTech Connect

The authors consider a mixture of heavy vapor molecules and a light carrier gas surrounding a liquid droplet. The vapor is described by a variant of the Klein-Kramers equation; the gas is described by the Navier-Stokes equations; the droplet acts as a heat source due to the released heat of condensation. The exchange of momentum and energy between the constituents of the mixture is taken into account by force terms in the kinetic equation and source terms in the Navier-Stokes equations. These are chosen to obtain maximal agreement with the irreversible thermodynamics of a gas mixture. The structure of the kinetic boundary layer around the sphere is determined from the self-consistent solution of this set of coupled equations with appropriate boundary conditions at the surface of the sphere. The kinetic equation is rewritten as a set of coupled moment equations. A complete set of solutions of these moment equations is constructed by numerical integration inward from the region far away from the droplet, where the background inhomogeneities are small. A technique developed earlier is used to deal with the numerical instability of the moment equations. The solutions obtained for given temperature and pressure profiles in the gas are then combined linearly such that they obey the boundary conditions at the droplet surface; from this solution source terms for the Navier-Stokes equation of the gas are constructed and used to determine improved temperature and pressure profiles for the background gas. For not too large temperature differneces between the droplet and the gas at infinity, self-consistency is reached after a few iterations. The method is applied to the condensation of droplets from a supersaturated vapor as well as to strong evaporation of droplets under the influence of an external heat source, where corrections of up to 40% are obtained.

Widder, M.E.; Titulaer, U.M. (Johannes-Kepler-Universitaet Linz (Austria))

1993-03-01

252

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

253

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

254

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

255

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.

256

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

Microsoft Academic Search

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

Philip Johnson

1998-01-01

257

Effects of proton irradiation on a gas phase in which condensation takes place. I Negative Mg-26 anomalies and Al-26. [applied to solar and meteoritic composition  

NASA Technical Reports Server (NTRS)

In the present paper, isotopic effects in magnesium generated in a proton-irradiated gas phase are examined, taking only (p,n), (p,d), and (p, alpha) reactions in magnesium, aluminum, and silicon into consideration. In the presence of proton radiation, the three elements are 'removed' from the gas phase by condensation. It is required that a value of Al-26/Al-27 greater than 6 times 10 to the -5th must be reached, consistent with the value deduced by Lee Papanastassiou, and Wasserburg (1976) from their studies of the Allende meteorite. The calculations show that fast aluminum condensation reduces the required proton fluence substantially, that a significant fraction of aluminum remains uncondensed when the above value of the Al-26/Al-27 ratio is reached, that a detectable MG-24 excess is very likely to occur, that detectable negative MG-28 anomalies can be generated, and that proton fluxes and irradiation times can be varied simultaneously, and over a wide range of values, without significant changes in the required proton fluence.

Heymann, D.; Dziczkaniec, M.; Walker, A.; Huss, G.; Morgan, J. A.

1978-01-01

258

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

259

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

260

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

261

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

262

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

PubMed

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

Fedichev, Petr O; Fischer, Uwe R

2003-12-12

263

Effects of hydrogen gas injection on the properties of SiO x nanoparticles synthesized by using an evaporation and condensation process  

NASA Astrophysics Data System (ADS)

SiO x nanoparticles were synthesized by using an evaporation and condensation process involving induction melting of silicon (Si) chunks followed by the injection of a H2/Ar mixed gas into the melt. In particular, this research studied the effects of hydrogen gas on the nanoparticles' microstructural and electrochemical properties, etc. During the microstructural analysis, regardless of H2 content, all the nanoparticles were observed to have random shapes; their average particle sizes were 30 ˜ 35 nm. However, a crystalline Si phase, even though it was a small amount, was formed when H2/Ar gas was injected. From the X-ray photoelectron spectroscopy (XPS) analysis, the amount of the SiO2 phase in SiO x decreased when the H2/Ar gas ratio was higher than 1.0 vol.%. Injected hydrogen produced a Si-H network in SiO x , and the Si-H concentration was independent of the amount of injected gas. Consequently, due to hydrogen incorporation, not only was a crystalline Si phase formed, but also the amount of the SiO2 phase decreased. In addition, Si-H bonds were formed in the nanoparticles. The crystalline Si phase and the relatively small amount of the SiO2 phase resulted in an enhancement of the Li-ion capacity when those nanoparticles were applied as an anode material for a Li-ion battery. Furthermore, cycle performance was improved even when hydrogen was incorporated. For the sample synthesized with 5.0-vol.% H2/Ar gas, the discharge capacity and the columbic efficiency at the 21 st cycle were 889.1 mAhg-1 and 95.0%, respectively.

Jun, Young-Sik; Jang, Bo-Yun; Kim, Joon-Soo; Lee, Jin-Seok; Choi, Chul-Hee; Han, Moon-Hee

2013-02-01

264

Numerical evaluation of surface condensers for geothermal power plants  

Microsoft Academic Search

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

O WERES

1984-01-01

265

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

266

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

PubMed

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

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

2012-01-01

267

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

PubMed Central

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

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

2012-01-01

268

Phase operators and blurring time of a pair-condensed Fermi gas H. Kurkjian, Y. Castin, A. Sinatra  

E-print Network

-wave scattering length characterizing the short range interactions in the cold gas can be ideally changed from to the case of fermions. Cold fermionic gases have been widely studied in the last decade [18­ 20

269

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

270

Excitonic Condensates  

NASA Astrophysics Data System (ADS)

Exciton condensation may occur not only in semiconductors, but also in mixed-valent compounds(H. J. Leder, Solid State Commun. 27), 579 (1978). Whereas the excitonic condensate in a semiconductor must be created artificially using optical pumping, the excitonic condensate in a mixed-valent compound is already built in by nature. This makes mixed-valent compounds ideal systems for studying the optical properties of excitonic condensates(V. Yu. Irkin and M. I. Katsnel'son, Zh. Eksp. Teor. Fiz. 90), 1080 (1986) [Sov. Phys. JETP 63, 631 (1986)]. Three surprising manifestations of exciton condensation in mixed-valent compounds are discussed in this talk: 1) electronic ferroelectricity, 2) ferroelectric resonance, and 3) a nonvanishing susceptibility for second-harmonic generation. A number of experiments are proposed which can give evidence for exciton condensation in mixed-valent compounds.

Portengen, T.

1998-03-01

271

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

272

CONDENSATION AND EVAPORATION FOR THERMALLY UNEQUILIBRATED PHASES  

E-print Network

CONDENSATION AND EVAPORATION FOR THERMALLY UNEQUILIBRATED PHASES R. A. Marcus1 , A. V. Fedkin2-K) equation for the rate of condensation of a gas or evaporation of a solid or liquid is used for systems, Tg, differs from that of the condensed phase, Ts . Here, we modify the H-K equation for this case

Grossman, Lawrence

273

The thermalization, condensation and flickering of photons  

NASA Astrophysics Data System (ADS)

Other than in a three-dimensional thermal photon gas as Planck?s blackbody radiation, photons can exhibit Bose–Einstein condensation, if the thermalization process is restricted to two motional degrees of freedom. This self-contained tutorial describes the thermalization mechanism, the condensation process and the quantum statistics of the photon condensates in detail.

Klaers, Jan

2014-12-01

274

Experimental studies of Bose-Einstein condensation  

E-print Network

Experimental studies of Bose-Einstein condensation Dallin S. Durfee and Wolfgang Ketterle-Einstein condensation in a dilute gas of sodium atoms. These include studies of static and dynamic behavior of the condensate, and of its coherence properties. Ã?1998 Optical Society of America OCIS codes: (020.0020) Atomic

Hart, Gus

275

Condensate dark matter stars  

SciTech Connect

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

Li, X.Y.; Harko, T.; Cheng, K.S., E-mail: lixinyu@hku.hk, E-mail: harko@hkucc.hku.hk, E-mail: hrspksc@hkucc.hku.hk [Department of Physics and Center for Theoretical and Computational Physics, The University of Hong Kong, Pok Fu Lam Road, Hong Kong (China)

2012-06-01

276

Quark and Gluon Condensates in Isospin Matter  

E-print Network

Applying the Hellmann-Feynman theorem to a charged pion gas, the quark and gluon condensates at low isospin density are determined by precise pion properties. At intermediate density around $ f_\\pi^2m_\\pi$, from both the estimation for the dilute pion gas and the calculation with Nambu--Jona-Lasinio model, the quark condensate is strongly and monotonously suppressed, while the gluon condensate is enhanced and can be larger than its vacuum value. This unusual behavior of the gluon condensate is universal for Bose condensed matter of mesons. Our results can be tested by lattice calculations at finite isospin density.

Lianyi He; Yin Jiang; Pengfei Zhuang

2008-12-01

277

Gas and Dust Condensations and a Peculiar Class 0 Object in the Lupus 3 Star-Forming Cloud  

Microsoft Academic Search

The Lupus 3 molecular cloud has been surveyed for dense gas and dust cores and embedded objects in radio [H13CO+ J=1-0 line and 1.2 mm continuum] and infrared [JHKsL'MN1 bands and H2 v=1-0 S(1) line] wavelengths. These observations unveil a filamentary cloud, three dense cores, an embedded millimeter-wave source (MMS), and an associated elongated object in the K band. The

K. Tachihara; M. Rengel; Y. Nakajima; N. Yamaguchi; P. André; R. Neuhäuser; T. Onishi; Y. Fukui; A. Mizuno

2007-01-01

278

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

279

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

280

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

281

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

282

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

283

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

284

Equilibrium condensation in a solar nebula  

NASA Technical Reports Server (NTRS)

In attempts to reconstruct the environment of condensation of solar system materials, particularly exemplified by certain meteorite components, the relative temperatures of the gas and the solid are of critical importance. The relationships that determine the heat balance in a circumsolar grain-gas system are examined. Fundamental considerations show that regardless of opacity or gas density, the gas will always be at a higher temperature than the solid in such regions of the system where condensation is possible. Implications of the characteristic temperature differential between the gas and the condensing solid are discussed.

Arrhenius, G.; De, R. R.

1973-01-01

285

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

286

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

287

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

288

Charged Condensation  

E-print Network

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

Gregory Gabadadze; Rachel A. Rosen

2007-06-15

289

Agglomeration of Ni-nanoparticles in the gas phase under gravity and microgravity conditions  

NASA Astrophysics Data System (ADS)

The agglomeration of metallic nanoparticles can be performed using the well-known inert gas condensation process. Unfortunately, thermal effects such as convection are created by the heating source and as a result the turbulent aerosol avoids ideal conditions. In addition, the sedimentation of large particles and/or agglomerates influences the self-assembly of particles. These negative effects can be eliminated by using microgravity conditions. Here we present the results of the agglomeration of nanoscale Ni-particles under gravity and microgravity conditions, the latter provided by adapted microgravity platforms namely the European sounding rocket MAXUS 8 and the European Parabolic Flight aircraft, Airbus A300 Zero-G.

Lösch, S.; Iles, G. N.; Schmitz, B.; Günther, B. H.

2011-12-01

290

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

Microsoft Academic Search

We have developed a nebular condensation model and a computational routine that potentially can account for the unequilibrated mineral assemblages in chondritic meteorites. The model assumes that as condensation proceeds a specified fraction (called the isolation degree, x) of the existing condensate is steadily withdrawn from reactive contact with the residual gas, presumably as a result of the growth and

Michail I. Petaev; John A. Wood

1998-01-01

291

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

292

Electron ejection by heavy particles as precursor of track formation in condensed matter  

NASA Astrophysics Data System (ADS)

The detailed knowledge of the structure of ion tracks is a key issue for our understanding of radiation effects in condensed matter. Important examples are the radial energy deposition profile by electronic excitation for numerical simulations of track formation (via "Coulomb explosion" or "thermal spike") in inert matter, and calculations of the RBE (relative biological effectiveness) of heavy particles in living matter (with important applications in dosimetry and hadrontherapy). In both cases, differential electron ejection cross sections are used as input parameter. The precursor of track formation is thus electron ejection from target atoms, or from the projectile itself. These primary electrons and their subsequent secondary interactions lead to the deposition of energy along and around the ion trajectory. We first briefly discuss "primary ionization" (binary encounter and soft electron emission, multiple collision sequences: "Fermi shuttle") common to single atoms (gas targets) and condensed matter. Then, specific effects in condensed matter (electron transport, jet-like electron spikes, wake effects due to collective excitation of plasmons and emission of shock wave electrons) will be presented. Finally, we concentrate on effects connected to the high density of deposited energy and strong perturbation induced by heavy particles such as heavy ions and clusters (reduction effects due to screening, transport and "sweeping away", multiple ionization, electronic temperatures from Auger spectroscopy).

Rothard, Hermann

2004-08-01

293

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

294

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

295

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

296

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

297

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

298

Condensation polyimides  

NASA Technical Reports Server (NTRS)

Polyimides belong to a class of polymers known as polyheterocyclics. Unlike most other high temperature polymers, polyimides can be prepared from a variety of inexpensive monomers by several synthetic routes. The glass transition and crystalline melt temperature, thermooxidative stability, toughness, dielectric constant, coefficient of thermal expansion, chemical stability, mechanical performance, etc. of polyimides can be controlled within certain boundaries. This versatility has permitted the development of various forms of polyimides. These include adhesives, composite matrices, coatings, films, moldings, fibers, foams and membranes. Polyimides are synthesized through both condensation (step-polymerization) and addition (chain growth polymerization) routes. The precursor materials used in addition polyimides or imide oligomers are prepared by condensation method. High molecular weight polyimide made via polycondensation or step-growth polymerization is studied. The various synthetic routes to condensation polyimides, structure/property relationships of condensation polyimides and composite properties of condensation polyimides are all studied. The focus is on the synthesis and chemical structure/property relationships of polyimides with particular emphasis on materials for composite application.

Hergenrother, P. M.

1989-01-01

299

GASCON and MHDGAS: FORTRAN IV computer codes for calculating gas and condensed-phase compositions in the coal-fired open-cycle MHD system  

Microsoft Academic Search

FORTRAN 4 computer codes were written to calculate the equilibrium partial pressures of the gaseous phase and the quantity and composition of the condensed phases in the open cycle MHD system. The codes are based on temperature-dependent equilibrium constants, mass conservation, the mass action law, and assumed ideal solution of compounds in each of two condensed phases. It is assumed

P. E. Blackburn

1977-01-01

300

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

301

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

302

Reactions in gas phase and condensed phase C6F5X (X = NCO, CH2CN) triggered by low energy electrons.  

PubMed

Electron attachment to gas phase perfluorophenylisocyanate (C(6)F(5)NCO) and perfluorophenyloacetonitrile (C(6)F(5)CH(2)CN) generates metastable parent anions within a very narrow resonance close to zero energy. At higher energies (2-7 eV), dissociative electron attachment (DEA) resonances are present, associated with the rupture of the C(6)F(5)-X bond (X = NCO, CH(2)CN) with the excess electron finally localised on either of the two fragments. The most intense fragment ion from C(6)F(5)CH(2)CN (M) is (M - HF)(-), which arises from the loss of a neutral HF from the transient anion and requires the concerted cleavage of two bonds and formation of a new molecule (HF). Most remarkably, this rather complex DEA reaction is by about two orders of magnitude more intense than the single bond cleavages (C(6)F(5)-X) leading to the complementary DEA reactions C(6)F(5) + X(-) and C(6)F(5)(-) + X. From both condensed molecules we observe desorption of F(-) and CN(-) and, additionally, O(-) from C(6)F(5)NCO. The desorption yields also show a resonant behaviour with the peak maxima in the range 8-12 eV, i.e., near or above the ionization energy, indicating that in electron stimulated desorption (ESD) highly excited resonances are involved. Ab initio calculations are performed in order to get information on the shape and energy of the molecular orbitals involved in low energy (<2 eV) electron attachment. PMID:19551199

Dabkowska, Iwona; Flosadóttir, Helga Dögg; Orzol, Mario; Ptasinska, Sylwia; Bald, Ilko; Ingólfsson, Oddur; Illenberger, Eugen

2009-07-14

303

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

304

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

USGS Publications Warehouse

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

Otton, James K.; Zielinski, Robert A.

2001-01-01

305

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

Microsoft Academic Search

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

W. V. Boynton

1975-01-01

306

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

307

Polariton condensates  

SciTech Connect

Most students of physics know about the special properties of Bose-Einstein condensates (BECs) as demonstrated in the two best-known examples: superfluid helium-4, first reported in 1938, and condensates of trapped atomic gases, first observed in 1995. (See the article by Wolfgang Ketterle in PHYSICS TODAY, December 1999, page 30.) Many also know that superfluid {sup 3}He and superconducting metals contain BECs of fermion pairs. An underlying principle of all those condensed-matter systems, known as quantum fluids, is that an even number of fermions with half-integer spin can be combined to make a composite boson with integer spin. Such composite bosons, like all bosons, have the property that below some critical temperature--roughly the temperature at which the thermal de Broglie wavelength becomes comparable to the distance between the bosons--the total free energy is minimized by having a macroscopic number of bosons enter a single quantum state and form a macroscopic, coherent matter wave. Remarkably, the effect of interparticle repulsion is to lead to quantum mechanical exchange interactions that make that state robust, since the exchange interactions add coherently.

Snoke, David; Littlewood, Peter [University of Pittsburgh, Pennsylvania (United States); University of Cambridge (United Kingdom)

2010-08-15

308

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

309

Condensation cleaning of particulate laden gases  

SciTech Connect

Particulate laden gas, especially those gases carrying particulates having a size in the micron or submicron range, are removed by humidifying the gas with water and thereafter subjecting the gas to indirect contact heat exchange sufficient to provide an energy transfer for water vapor condensation of at least 5 horsepower per 1000 cfm. Heat exchange is accomlished by passing the gas downwardly through an exchange element having smooth and vertical gas passages of a relatively large dimension.

Devries, E.

1981-08-18

310

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 ...

311

Calculations predict condensate movement at T junctions  

Microsoft Academic Search

A model for the prediction of the route preference of condensate at T junctions in gas-transportation pipelines has been developed. The double-stream model can be applied to sharpedged and radiused, regular, and reduced T and Y junctions. The model permits an understanding of condensate behavior at a junction. From this knowledge, precautions can be taken to install gas-liquid separators at

J. M. H. Fortuin; P. J. Hamersma; J. Hart; H. J. Smit; W. P. Baan

1991-01-01

312

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

313

40 CFR 65.151 - Condensers used as control devices.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Condensers used as control devices. 65.151 Section 65.151...FEDERAL AIR RULE Closed Vent Systems, Control Devices, and Routing to a Fuel Gas System...Process § 65.151 Condensers used as control devices. (a) Condenser...

2010-07-01

314

40 CFR 65.151 - Condensers used as control devices.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Condensers used as control devices. 65.151 Section 65.151...FEDERAL AIR RULE Closed Vent Systems, Control Devices, and Routing to a Fuel Gas System...Process § 65.151 Condensers used as control devices. (a) Condenser...

2011-07-01

315

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

Microsoft Academic Search

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

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

1997-01-01

316

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

317

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

318

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

319

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

320

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

321

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

322

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

323

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

324

Condensation heat transfer  

NASA Astrophysics Data System (ADS)

The paper gives a brief description of some of the better understood aspects of condensation heat transfer and includes discussion of the liquid-vapour interface, natural and forced convection laminar film condensation and dropwise condensation.

Rose, J. W.

325

Understanding Condensation  

NSDL National Science Digital Library

Monica Hartman, Assistant Director for Science in St. Clair County, Michigan, conducted this research while she was the learning specialist in a small suburban district just outside a large Midwestern city. While teaching full time in this district she was also completing her doctoral program in education at the University of Michigan. In this chapter, she tells the story of a "science talk" about condensation among fifth graders. She acted as a source and facilitator of change as she and the fifth-grade teacher worked collaboratively to help students share responsibility for their own learning. She describes their continual assessment of student understanding that occurred as their students struggled to explain observations and as they, the teachers, carefully resisted the temptation to end the struggle by saying "that's right!"

Hartman, Monica

2007-12-01

326

CONDENSATION OF THE HIGH-FEO SILICATES IN PRIMITIVE CHONDRITES: STILL A PROBLEM. A. V. Fedkin1  

E-print Network

CONDENSATION OF THE HIGH-FEO SILICATES IN PRIMITIVE CHONDRITES: STILL A PROBLEM. A. V. Fedkin1 condensates [1, 2]. In solar gas, all Fe condenses as metallic NiFe and almost all Mg and Si as pure- leation kinetics prevented metallic Fe from condensing at its equilibrium condensation temperature, Teq

Grossman, Lawrence

327

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

328

40 CFR 174.705 - Inert ingredients from sexually compatible plant.  

Code of Federal Regulations, 2014 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...

2014-07-01

329

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

330

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

331

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

332

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

333

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

Federal Register 2010, 2011, 2012, 2013, 2014

...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

334

Asymptotic Behavior of Rotating Rarefied Gases with Evaporation and Condensation  

E-print Network

Asymptotic Behavior of Rotating Rarefied Gases with Evaporation and Condensation Liliana M. G of the cylindrical Couette flow problem for a rarefied rotating gas with evaporation and condensation is studied when difference of the evaporating gas; (ii) the angular velocity difference of the cylinders; and (iii

Sharipov, Felix

335

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

336

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

337

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

338

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

339

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

340

Condensation model for the ESBWR passive condensers  

SciTech Connect

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

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

2012-07-01

341

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

Microsoft Academic Search

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

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

1996-01-01

342

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

Federal Register 2010, 2011, 2012, 2013, 2014

...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

343

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

344

Secondary condenser Cooling water  

E-print Network

Receiver Secondary condenser LC LC Reboiler TC PC Cooling water PC FCPC Condenser LC XC Throttling valve ¨ mx my l© ª y s § y m «¬ ly my wx l n® ® x np © ¯ Condenser Column Compressor Receiver Super-heater Decanter Secondary condenser Reboiler Throttling valve Expansion valve Cooling water

Skogestad, Sigurd

345

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

346

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

347

A novel nickel metal-organic framework with fluorite-like structure: gas adsorption properties and catalytic activity in Knoevenagel condensation.  

PubMed

A new non-interpenetrating 3D metal-organic framework {[Ni4(?6-MTB)2(?2-H2O)4(H2O)4]·10DMF·11H2O}n (DMF = N,N'-dimethylformamide) built from nickel(ii) ions as connectors and methanetetrabenzoate ligands (MTB(4-)) as linkers has been synthesized and characterized. The single crystal X-ray diffraction showed that complex exhibits CaF2-like fluorite structure topology and four types of 3D channels with sizes about 12.6 × 9.4 Å(2), 9.4 × 8.0 Å(2), 12.6 × 11.7 Å(2) and 14.9 × 14.9 Å(2), which are filled with guest molecules. Conditions of the activation of the compound have been studied and optimized by powder X-ray diffraction during in situ heating, thermogravimetric analysis and infrared spectroscopy. Nitrogen and carbon dioxide adsorption showed that the activated sample exhibits a BET specific surface area of 700 m(2) g(-1) and a carbon dioxide uptake of 12.36 wt% at 0 °C, which are the highest values reported for the compounds of the MTB(4-) series. The complex was tested in Knoevenagel condensation of aldehydes and active methylene compounds. Straightforward dependence of the substrate conversion on the size of used aldehyde was established. A possible mechanism of Knoevenagel condensation over a MTB(4-) containing a metal-organic framework was proposed. PMID:24435475

Almáši, Miroslav; Zele?ák, Vladimír; Opanasenko, Maksym; Cejka, Jí?í

2014-03-01

348

Grand canonical Monte Carlo simulation study of capillary condensation between nanoparticles  

Microsoft Academic Search

Capillary condensation at the nanoscale differs from condensation in the bulk phase, because it is a strong function of surface geometry and gas-surface interactions. Here, the effects of geometry on the thermodynamics of capillary condensation at the neck region between nanoparticles are investigated via a grand canonical Monte Carlo simulation using a two-dimensional lattice gas model. The microscopic details of

Seonmin Kim; Sheryl H. Ehrman

2007-01-01

349

Two Heat-Transfer Improvements for Gas Liquefiers  

NASA Technical Reports Server (NTRS)

Two improvements in heat-transfer design have been investigated with a view toward increasing the efficiency of refrigerators used to liquefy gases. The improvements could contribute to the development of relatively inexpensive, portable oxygen liquefiers for medical use. A description of the heat-transfer problem in a pulse-tube refrigerator is prerequisite to a meaningful description of the first improvement. In a pulse-tube refrigerator in particular, one of in-line configuration heat must be rejected from two locations: an aftercooler (where most of the heat is rejected) and a warm heat exchanger (where a small fraction of the total input power must be rejected as heat). Rejection of heat from the warm heat exchanger can be problematic because this heat exchanger is usually inside a vacuum vessel. When an acoustic-inertance tube is used to provide a phase shift needed in the pulse-tube cooling cycle, another problem arises: Inasmuch as the acoustic power in the acoustic-inertance tube is dissipated over the entire length of the tube, the gas in the tube must be warmer than the warm heat exchanger in order to reject heat at the warm heat exchanger. This is disadvantageous because the increase in viscosity with temperature causes an undesired increase in dissipation of acoustic energy and an undesired decrease in the achievable phase shift. Consequently, the overall performance of the pulse-tube refrigerator decreases with increasing temperature in the acoustic-inertance tube. In the first improvement, the acoustic-inertance tube is made to serve as the warm heat exchanger and to operate in an approximately isothermal condition at a lower temperature, thereby increasing the achievable phase shift and the overall performance of the refrigerator. This is accomplished by placing the acoustic-inertance tube inside another tube and pumping a cooling fluid (e.g., water) in the annular space between the tubes. Another benefit of this improvement is added flexibility of design to locate the warm heat-rejection components outside the vacuum vessel. The second improvement is the development of a compact radial-flow condenser characterized by a very high heat transfer coefficient and a small pressure drop.

Martin, Jerry L.

2005-01-01

350

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

351

Low Energy Nuclear Transmutation in Condensed Matter Induced by D2 Gas Permeation Through pd Complexes:. Correlation Between Deuterium Flux and Nuclear Products  

Microsoft Academic Search

Observations of low energy nuclear reactions induced by D2 gas permeation through Pd complexes (Pd\\/CaO\\/Pd) were presented at ICCF-91 and in a paper2 published in the Japanese Journal of Applied Physics. When Cs was added on the surface of a Pd complex, Pr emerged on the surface while Cs decreased after the Pd complex was subjected to D2 gas permeation.

Y. Iwamura; T. Itoh; M. Sakano; S. Sakai; S. Kuribayashi

2005-01-01

352

Condensates from fields of Turkmenistan as motor fuel components  

SciTech Connect

The differences in condensate produced in 14 gas-condensate fields are examined. The first group of condensates have high contents of cyclic hydrocarbons; the second has a high content of pariffinic hydrocarbons. Both the high-cyclic and high-paraffin condensates can serve as feedstocks for the chemical, petrochemical, and biochemical industries. The naphtha cuts obtained form the condensates with end points of 150 and 180 degrees C, do not meet the requirements of the GOST for octane number, initial boiling point or 105 distillation point. The diesel fuel cuts obtained have cetane numbers far above the GOST requirements.

Kul'dzhaev, B.A.; Sergienko, S.R.; Tsibrova, E.G.

1986-03-01

353

Dynamics of capillary condensation in lattice gas models of confined fluids: a comparison of dynamic mean field theory with dynamic Monte Carlo simulations.  

PubMed

This article addresses the accuracy of a dynamic mean field theory (DMFT) for fluids in porous materials [P. A. Monson, J. Chem. Phys. 128, 084701 (2008)]. The theory is used to study the relaxation processes of fluids in pores driven by step changes made to a bulk reservoir in contact with the pore. We compare the results of the DMFT to those obtained by averaging over large numbers of dynamic Monte Carlo (DMC) simulation trajectories. The problem chosen for comparison is capillary condensation in slit pores, driven by step changes in the chemical potential in the bulk reservoir and involving a nucleation process via the formation of a liquid bridge. The principal difference between the DMFT results and DMC is the replacement of a distribution of nucleation times and location along the pore for the formation of liquid bridges by a single time and location. DMFT is seen to yield an otherwise qualitatively accurate description of the dynamic behavior. PMID:23802978

Edison, John R; Monson, Peter A

2013-06-21

354

Condensed combustion products of aluminized propellants. 1. A technique for investigating the evolution of disperse-phase particles  

SciTech Connect

This paper describes a technique for investigating the evolution of the condensed combustion products of metallized propellants. The technique involves freezing the combustion products of a propellant sample at different distances from the burning surface by mixing with a cocurrent cold flow of an inert diluent gas, followed by collecting the particles in metal sieves and in an aerosol filter. The technique allows one to determine particles sizes from 1.2 {mu}m to maximum as well as to establish the content of neat aluminum in particles at pressures up to 80 atm. The site of freezing is set by varying the length of the guard tube which prevents the flame from contacting with the diluent gas flow. The procedures and results of the particle-size and chemical analyses are described. Apart from changes in the mass distribution of particles in size, the evolution of the particles, as they depart from the burning surface, is characterized by a dependence of the mass fraction of aluminum in particles on the reaction time which involves the residence times in the guard tube and in the zone of the initial mixing of the flow of combustion products with the cocurrent flow of the diluent gas.

Glotov, O.G.; Zyryanov, V.Y. [Inst. of Chemical Kinetics and Combustion, Novosibirsk (Russian Federation)

1995-07-01

355

Theoretical analysis of condensation in the presence of noncondensable gases as applied to open cycle OTEC condensers  

NASA Astrophysics Data System (ADS)

The open cycle ocean thermal energy conversion condenser was analyzed from a theoretical standpoint. Interfacial temperature profiles and gas concentrations in the axial direction were determined, and their effects on the rate of condensation studied. For the analysis, the vapor phase was modeled using diffusion equations for simultaneous heat and mass transfer processes, while the liquid phase was modeled using a falling film analysis. This analysis was then applied to a plate fin condenser, and the effect of varying the fin density along the condenser lengths was investigated. General engineering aspects of heat exchanger design are discussed for condensation of vapor mixtures in the presence of noncondensable gases.

Panchal, C. B.; Bell, K. J.

356

Modeling unit cell interactions for the microstructure of a heterogeneous explosive: detonation diffraction past an inert sphere  

SciTech Connect

We describe an approach being used to model multi-phase blast explosive, that is mostly condensed explosive by volume with inert embedded particles. The asymptotic theory of detonation shock dynamics is used to describe the detonation shock propagation in the explosive. The shock motion rule in the explosive requires that the shock move at a normal speed that depends on the shock curvature. The angle that the shock makes with the particle boundary is also prescribed. We describe theory that can be used to predict the behavior of a collection of such detonation shock/particle interactions in the larger aggregate. A typical unit cell problem of a detonation shock diffraction over a sphere is analyzed by analytical and numerical means and the properties of an ensemble of such unit cell problems is discussed with implications for the macroscopic limiting behavior of the heterogeneous explosive.

Bdzil, John B [Los Alamos National Laboratory; Stewart, Donald S [Los Alamos National Laboratory; Walter, John W [Los Alamos National Laboratory; Aida, Toru [Los Alamos National Laboratory

2009-01-01

357

Condensate Mixtures and Tunneling  

SciTech Connect

The experimental study of condensate mixtures is a particularly exciting application of the recently developed atomic-trap Bose-Einstein condensate (BEC) technology: such multiple condensates represent the first laboratory systems of distinguishable boson superfluid mixtures. In addition, as the authors point out in this paper, the possibility of inter-condensate tunneling greatly enhances the richness of the condensate mixture physics. Not only does tunneling give rise to the oscillating particle currents between condensates of different chemical potentials, such as those studied extensively in the condensed matter Josephson junction experiments, it also affects the near-equilibrium dynamics and stability of the condensate mixtures. In particular, the stabilizing influence of tunneling with respect to spatial separation (phase separation) could be of considerable practical importance to the atomic trap systems. Furthermore, the creation of mixtures of atomic and molecular condensates could introduce a novel type of tunneling process, involving the conversion of a pair of atomic condensate bosons into a single molecular condensate boson. The static description of condensate mixtures with such type of pair tunneling suggests the possibility of observing dilute condensates with the liquid-like property of a self-determined density.

Timmermans, E.

1998-09-14

358

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

359

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

360

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

361

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

362

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

363

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

364

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

365

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

366

In situ observation of sub-Poissonian atom-number fluctuations in a repulsive 1D Bose gas: quantum quasi-condensate and strongly interacting regimes  

E-print Network

In situ observation of sub-Poissonian atom-number fluctuations in a repulsive 1D Bose gas: quantum for Quantum-Atom Optics, School of Mathematics and Physics, University of Queensland, Brisbane, Queensland 4072, Australia (Dated: March 21, 2011) We report on local measurements of atom number fluctuations

367

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

368

Condensation Particle Counter  

E-print Network

Model 3007 Condensation Particle Counter Operation and Service Manual 1930035, Revision C August 2002 P a r t i c l e I n s t r u m e n t s #12;#12;Model 3007 Condensation Particle Counter Operation............................................................................V 1. UNPACKING AND PARTS IDENTIFICATION..................................1 Unpacking the Condensation

Weber, Rodney

369

in Condensed Matter Physics  

E-print Network

Master in Condensed Matter Physics ­ Master académique #12;2 #12;3 Students at the University. Condensed matter physics is about explaining and predicting the relationship between the atomic, and broad education in the field of condensed matter physics · introduce you to current research topics

van der Torre, Leon

370

Condensation in Microchannels  

Microsoft Academic Search

Condensation in microchannels has applications in a wide variety of advanced microthermal devices. Presented here is a review of both experimental and theoretical analyses of condensation in these microchannels, with special attention given to the effects of channel diameter and surface conditions on the flow regimes of condensing flows occurring in these channels. This review suggests that surface tension, rather

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

2008-01-01

371

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

372

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

373

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

374

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

375

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

376

Low Energy Nuclear Transmutation in Condensed Matter Induced by D2 Gas Permeation Through pd Complexes:. Correlation Between Deuterium Flux and Nuclear Products  

NASA Astrophysics Data System (ADS)

Observations of low energy nuclear reactions induced by D2 gas permeation through Pd complexes (Pd/CaO/Pd) were presented at ICCF-91 and in a paper2 published in the Japanese Journal of Applied Physics. When Cs was added on the surface of a Pd complex, Pr emerged on the surface while Cs decreased after the Pd complex was subjected to D2 gas permeation. When Sr was added to the surface, Mo emerged while the Sr decreased after D2 gas permeation. The isotopic composition of the detected Mo was different from the natural abundance. In this paper, recent progress of our research is described. The detected Pr was confirmed by various methods such as TOF-SIMS, XANES, X-ray Fluorescence Spectrometry and ICP-MS. Analysis of the depth profile of Pr indicated that a very thin surface region up to 100 Å was the active transmutation zone. Many experimental results showed that the quantity of Pr was proportional to the deuterium flux through Pd complex. The cross-section of transmutation of Cs into Pr can be roughly estimated at 1 barn if we consider the deuterium flux as an ultra low energy deuteron beam.

Iwamura, Y.; Itoh, T.; Sakano, M.; Sakai, S.; Kuribayashi, S.

2005-12-01

377

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

378

Steady evaporation and condensation of isolated clouds in hot plasma  

NASA Technical Reports Server (NTRS)

The evaporation and condensation of an isolated cloud embedded in a thermally stable hot gas is studied under the assumption that the ambient hot gas is in thermal equilibrium at constant temperature and that the cloud is large enough that classical conduction is valid. It is found that the cloud will evaporate provided that it is smaller than the Field length, which gives the maximum range of thermal conduction. A large cloud can condense only if the pressure exceeds the saturated vapor pressure p(sat). The pressure required for condensation increases as the cloud radius decreases, until condensation becomes impossible. Since p(sat) is close to the maximum pressure at which the hot gas can exist in equilibrium, condensation is likely to occur under unsteady conditions. The Compton-bremsstrahlung case is treated as an example.

Mckee, Christopher F.; Begelman, Mitchell C.

1990-01-01

379

Electron-induced damage of biotin studied in the gas phase and in the condensed phase at a single-molecule level  

NASA Astrophysics Data System (ADS)

Biotin is an essential vitamin that is, on the one hand, relevant for the metabolism, gene expression and in the cellular response to DNA damage and, on the other hand, finds numerous applications in biotechnology. The functionality of biotin is due to two particular sub-structures, the ring structure and the side chain with carboxyl group. The heterocyclic ring structure results in the capability of biotin to form strong intermolecular hydrogen and van der Waals bonds with proteins such as streptavidin, whereas the carboxyl group can be employed to covalently bind biotin to other complex molecules. Dissociative electron attachment (DEA) to biotin results in a decomposition of the ring structure and the carboxyl group, respectively, within resonant features in the energy range 0-12 eV, thereby preventing the capability of biotin for intermolecular binding and covalent coupling to other molecules. Specifically, the fragment anions (M-H)-, (M-O)-, C3N2O-, CH2O2-, OCN-, CN-, OH- and O- are observed, and exemplarily the DEA cross section of OCN- formation is determined to be 3 × 10-19 cm2. To study the response of biotin to electrons within a complex condensed environment, we use the DNA origami technique and determine a dissociation yield of (1.1 ± 0.2) × 10-14 cm2 at 18 eV electron energy, which represents the most relevant energy for biomolecular damage induced by secondary electrons. The present results thus have important implications for the use of biotin as a label in radiation experiments.

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

2013-08-01

380

Potential Condensed Fuel for the Milky Way  

E-print Network

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

M. E. Putman

2006-03-23

381

Impurity condensation in liquid and solid helium  

NASA Astrophysics Data System (ADS)

It is shown from an analysis of x-ray structural and IR spectroscopic studies that when impurity particles are introduced into liquid or solid helium, the clusters formed in the cold part of a gas jet have a pronounced spatial separation of impurities with different volatility. In particular, in the condensation of partially dissociated diatomic molecules the atoms are highly concentrated near and on the surface of the clusters. Segregation of this kind is preserved in the condensate in liquid helium, which consists of clusters stuck together into a porous structure; in solid helium clusters are isolated. The presence of high concentrations of atoms in the surface layer at the boundary with condensed helium explains the specifics of condensate behavior observed by methods of optical spectroscopy, ESR, and thermometry. An experimental strategy is developed for detecting the formation of an impurity-helium solid.

Gordon, E. B.

2004-10-01

382

Bose-Einstein Condensation of Pions  

E-print Network

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

Viktor Begun; Mark Gorenstein

2007-09-10

383

Condensation Front Migration in a Protoplanetary Nebula  

NASA Technical Reports Server (NTRS)

Condensation front dynamics are investigated in the mid-solar nebula region. A quasi-steady model of the evolving nebula is combined with equilibrium vapor pressure curves to determine evolutionary condensation fronts for selected species. These fronts are found to migrate inwards from the far-nebula to final positions during a period of 10(exp 7) years. The physical process governing this movement is a combination of local viscous heating and luminescent heating from the central star. Two luminescent heating models are used and their effects on the ultimate radial position of the condensation front are discussed. At first the fronts move much faster than the nebular accretion velocity, but after a time the accreting gas and dust overtakes the slowing condensation front.

Davis, Sanford S.

2004-01-01

384

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

SciTech Connect

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

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

2005-10-15

385

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

386

Gas-phase infrared spectroscopy of the protonated dipeptides H+PheAla and H+AlaPhe compared to condensed-phase results  

NASA Astrophysics Data System (ADS)

The influence of the physical environment on the structures of biomolecules is considered here for the dipeptide model H+AlaPhe cation, by making use of infrared multiple-photon dissociation (IRMPD) spectroscopy complemented by DFT calculations. The gas-phase structures of this peptide are also compared to the related peptide cations H+PheAla and H+AlaAla. The gas-phase IRMPD spectra of the Phe-containing cations are compared to previous studies, including the X-ray-crystallographic crystal structure for the H+AlaPheCl-.2H2O salt, a recent IRMPD spectrum of H+AlaAla, and a recent determination of the IR absorption spectrum of the H+AlaPheCl- salt in a liquid-crystal host matrix, as well as recent cryogenic ion trap results for H+TyrAla and H+AlaTyr. Between the gas-phase H+AlaPhe ion and the H+AlaPheCl-.2H2O crystal a conformational switch is observed, induced by hydrogen bonding with a water of crystallization, involving a 180° rotation of the COOH group. The hoped-for comparison of the gas-phase IR spectra with the liquid-crystal matrix IR spectrum was frustrated, because the literature matrix spectrum seems most likely to be that of a protonated homodimer of the dipeptide rather than the protonated monomer. The IRMPD spectra of H+AlaPhe and H+PheAla are very similar, with only minor peak shifts suggesting small differences in local interactions within a similar overall architecture. The H+AlaAla spectrum was also similar, and no significant reorganization of the structure seems to result from the presence or position of the aromatic ring. The spectra give highly satisfactory matches to the predicted IR spectra computed for the most stable conformers of the protonated dipeptides. It is suggested that the NH3+ proton is shared through hydrogen bonding to the amide CO, giving a distinctive broadening of the associated H-bending mode.

Dunbar, Robert C.; Steill, Jeffrey D.; Polfer, Nick C.; Oomens, Jos

2009-06-01

387

Vapor Condensation in a Shock Tube; Condensation Coefficient for sec-Butyl Alcohol  

Microsoft Academic Search

The condensation of sec-butyl alcohol vapor has been observed in a glass shock tube instrumented to observe the variations in monochromatic light transmittance caused by the growth of a liquid film of sec-butyl alcohol on the shock-tube walls. The film thickness was obtained from the transmittance. The gas pressure during condensation was monitered by strain gages, and the wall temperature

Paul A. Kicska; Wesley R. Smith

1967-01-01

388

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

389

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

390

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

391

Bose-Einstein condensation in low-dimensional traps  

NSDL National Science Digital Library

The authors demonstrate the possibility of Bose-Einstein condensation of an ideal Bose gas confined by one- and two-dimensional power-law traps. Problem 6.66 in Gould & Tobochnik is based on this paper.

Bagnato, Vanderlei; Kleppner, Daniel

2011-05-26

392

Optimizing Steam and Condensate System: A Case Study  

E-print Network

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

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

393

MOBILE BED FLUX FORCE/CONDENSATION SCRUBBERS  

EPA Science Inventory

The report gives results of an experimental determination of fine particle collection in mobile bed scrubbers. Particle collection efficiency increased greatly as the gas-phase pressure drop increased. With no water vapor condensation, the performance capability of a mobile bed s...

394

Condensate-removal device for heat exchangers  

NASA Technical Reports Server (NTRS)

Device comprises array of perforated tubes manifolded together and connected to a vacuum suction device. Vacuum applied to these tubes pulls mixture of condensate and effluent gas through perforations and along length of tubes to discharge device. Discharge device may be a separator which separates water vapor from effluent air and allows recirculation of both of them.

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

1973-01-01

395

Condensation in the primitive solar nebula  

Microsoft Academic Search

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

Lawrence Grossman

1972-01-01

396

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

PubMed

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

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

2014-08-26

397

Recovery of hydrogen from ammonia synthesis purge gas  

Microsoft Academic Search

In a process for the recovery of hydrogen from compressed purge gas withdrawn from a recyling gas stream of an ammonia synthesis wherein the hydrogen is separated from the purge gas by partial condensation at cryogenic temperatures, refrigeration is provided by expanding and evaporating the condensate so formed, and the partial pressure of the expanded condensate is lowered by withdrawing

A. A. Haslam; W. H. Isalski; T. R. Tomlinson

1983-01-01

398

Quark Condensates: Flavour Dependence  

E-print Network

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

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

2007-03-23

399

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

400

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

401

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

402

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

403

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

Code of Federal Regulations, 2014 CFR

...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

404

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

405

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

406

Condensation and large cardinals.  

E-print Network

??Wir definieren lokale Clubmengenkondensation (Local Club Condensation), ein Prinzip, welches Eigenschaften von Gödels Kondensationsprinzip isoliert und verallgemeinert. Wir zeigen, dass wir über einem beliebigen Modell… (more)

Holy, Peter

2010-01-01

407

Of Matters Condensed  

E-print Network

The American Physical Society (APS) March Meeting of condensed matter physics has grown to nearly 10,000 participants, comprises 23 individual APS groups, and even warrants its own hashtag (#apsmarch). Here we analyze the text and data from March Meeting abstracts of the past nine years and discuss trends in condensed matter physics over this time period. We find that in comparison to atomic, molecular, and optical physics, condensed matter changes rapidly, and that condensed matter appears to be moving increasingly toward subject matter that is traditionally in materials science and engineering.

Shulman, Michael

2015-01-01

408

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

409

Experimental investigation of the film condensation of sulfur hexafluoride on a finned overhead surface  

SciTech Connect

The results of investigating the film condensation of sulfur hexafluoride on a finned overhead surface are presented. An experimental apparatus with controlled heat removal is described. The negative influence of noncondensing impurities in the condensible gas and subcooling of the condensation surface on the rate of the process is demonstrated. Methods of eliminating these effects are considered.

Salekhov, L.T.; Mazurin, I.M.

1987-08-01

410

VAPOR-CONDENSED PHASE PROCESSES IN THE EARLY SOLAR SYSTEM. L. Grossman. Department of the  

E-print Network

VAPOR-CONDENSED PHASE PROCESSES IN THE EARLY SOLAR SYSTEM. L. Grossman. Department@uchicago.edu. Equilibrium thermodynamic calculations of the sequence of condensation of phases from a cooling gas of solar that they underwent melting after condensation, crystallizing into the same phase as- semblage as their precursors

Grossman, Lawrence

411

Quantum kinetic theory: modelling and numerics for Bose-Einstein condensation  

E-print Network

Quantum kinetic theory: modelling and numerics for Bose-Einstein condensation Weizhu Bao1 , Lorenzo Bose-Einstein condensation in a dilute gas mathematically interesting and numerically challenging phenomenon of bosons condensation. We also show that the resulting schemes can be evaluated with the use

Markowich, Peter A.

412

DRAFT: JStatPhys, May 28, 2009 On the nature of BoseEinstein condensation  

E-print Network

DRAFT: JStatPhys, May 28, 2009 On the nature of Bose­Einstein condensation in disordered systems­Einstein condensation in the random eigenstates if and only if the same occurs in the one­particle kinetic­energy eigenstates, which corresponds to the generalized condensation of the free Bose gas. Moreover, we prove

413

BoseEinstein condensation, fluctuations, and recurrence relations in statistical mechanics  

E-print Network

Bose­Einstein condensation, fluctuations, and recurrence relations in statistical mechanics W. J­Einstein condensation in the ideal gas by using recurrence relations for the partition function. The grand canonical ensemble gives inaccurate results for certain properties of the condensate that are accurately provided

Mullin, William J.

414

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

415

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

416

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

417

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

418

Condensation Energy of a Spacetime Condensate  

E-print Network

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

Clovis Jacinto de Matos; Pavol Valko

2010-12-17

419

Integrated vacuum absorption steam cycle gas separation  

DOEpatents

Methods and systems for separating a targeted gas from a gas stream emitted from a power plant. The gas stream is brought into contact with an absorption solution to preferentially absorb the targeted gas to be separated from the gas stream so that an absorbed gas is present within the absorption solution. This provides a gas-rich solution, which is introduced into a stripper. Low pressure exhaust steam from a low pressure steam turbine of the power plant is injected into the stripper with the gas-rich solution. The absorbed gas from the gas-rich solution is stripped in the stripper using the injected low pressure steam to provide a gas stream containing the targeted gas. The stripper is at or near vacuum. Water vapor in a gas stream from the stripper is condensed in a condenser operating at a pressure lower than the stripper to concentrate the targeted gas. Condensed water is separated from the concentrated targeted gas.

Chen, Shiaguo (Champaign, IL); Lu, Yonggi (Urbana, IL); Rostam-Abadi, Massoud (Champaign, IL)

2011-11-22

420

Gas-separation process  

DOEpatents

A process for separating condensable organic components from gas streams. The process makes use of a membrane made from a polymer material that is glassy and that has an unusually high free volume within the polymer material.

Toy, Lora G. (San Francisco, CA); Pinnau, Ingo (Palo Alto, CA); Baker, Richard W. (Palo Alto, CA)

1994-01-01

421

MOLECULAR SPECTROSCPY AND REACTIONS OF ACTINIDES IN THE GAS PHASE AND CRYOGENIC MATRICES  

SciTech Connect

In this chapter we review the spectroscopic data for actinide molecules and the reaction dynamics for atomic and molecular actinides that have been examined in the gas phase or in inert cryogenic matrices. The motivation for this type of investigation is that physical properties and reactions can be studied in the absence of external perturbations (gas phase) or under minimally perturbing conditions (cryogenic matrices). This information can be compared directly with the results from high-level theoretical models. The interplay between experiment and theory is critically important for advancing our understanding of actinide chemistry. For example, elucidation of the role of the 5f electrons in bonding and reactivity can only be achieved through the application of experimentally verified theoretical models. Theoretical calculations for the actinides are challenging due the large numbers of electrons that must be treated explicitly and the presence of strong relativistic effects. This topic has been reviewed in depth in Chapter 17 of this series. One of the goals of the experimental work described in this chapter has been to provide benchmark data that can be used to evaluate both empirical and ab initio theoretical models. While gas-phase data are the most suitable for comparison with theoretical calculations, there are technical difficulties entailed in generating workable densities of gas-phase actinide molecules that have limited the range of species that have been characterized. Many of the compounds of interest are refractory, and problems associated with the use of high temperature vapors have complicated measurements of spectra, ionization energies, and reactions. One approach that has proved to be especially valuable in overcoming this difficulty has been the use of pulsed laser ablation to generate plumes of vapor from refractory actinide-containing materials. The vapor is entrained in an inert gas, which can be used to cool the actinide species to room temperature or below. For many spectroscopic measurements, low temperatures have been achieved by co-condensing the actinide vapor in rare gas or inert molecule host matrices. Spectra recorded in matrices are usually considered to be minimally perturbed. Trapping the products from gas-phase reactions that occur when trace quantities of reactants are added to the inert host gas has resulted in the discovery of many new actinide species. Selected aspects of the matrix isolation data were discussed in chapter 17. In the present chapter we review the spectroscopic matrix data in terms of its relationship to gas-phase measurements, and update the description of the new reaction products found in matrices to reflect the developments that have occurred during the past two years. Spectra recorded in matrix environments are usually considered to be minimally perturbed, and this expectation is borne out for many closed shell actinide molecules. However, there is growing evidence that significant perturbations can occur for open shell molecules, resulting in geometric distortions and/or electronic state reordering. Studies of actinide reactions in the gas phase provide an opportunity to probe the relationship between electronic structure and reactivity. Much of this work has focused on the reactions of ionic species, as these may be selected and controlled using various forms of mass spectrometry. As an example of the type of insight derived from reaction studies, it has been established that the reaction barriers for An+ ions are determined by the promotion energies required to achieve the 5fn6d7s configuration. Gas-phase reaction studies also provide fundamental thermodynamic properties such as bond dissociation and ionization energies. In recent years, an increased number of gas-phase ion chemistry studies of bare (atomic) and ligated (molecular) actinide ions have appeared, in which relevant contributions to fundamental actinide chemistry have been made. These studies were initiated in the 1970's and carried out in an uninterrupted way over the course of the past three d

Heaven, Michael C.; Gibson, John K.; Marcalo, Joaquim

2009-02-01

422

Bose-Einstein condensation on quantum graphs  

E-print Network

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

Jens Bolte; Joachim Kerner

2014-03-02

423

Dynamic condensation blocking in cryogenic refueling  

NASA Astrophysics Data System (ADS)

We demonstrate that a negative feedback between vapor pressure and condensation rate may be established in two-phase systems during vapor compression with rates of practical importance. As a result, dynamic condensation blocking occurs. The effect is studied numerically in the case of filling a no-vent insulated tank by liquid hydrogen. It is shown that the filling dynamics quite sensitively depends on the filling rate, and for sufficiently fast filling rates consist of a fast stage dominated by gas compression and a slow stage governed by heat conduction in the liquid.

Osipov, V. V.; Muratov, C. B.

2008-12-01

424

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

425

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

426

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

427

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

428

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

429

Freeze-Tolerant Condensers  

NASA Technical Reports Server (NTRS)

Two condensers designed for use in dissipating heat carried by working fluids feature two-phase, self-adjusting configurations such that their working lengths automatically vary to suit their input power levels and/or heat-sink temperatures. A key advantage of these condensers is that they can function even if the temperatures of their heat sinks fall below the freezing temperatures of their working fluids and the fluids freeze. The condensers can even be restarted from the frozen condition. The top part of the figure depicts the layout of the first condenser. A two-phase (liquid and vapor) condenser/vapor tube is thermally connected to a heat sink typically, a radiatively or convectively cooled metal panel. A single-phase (liquid) condensate-return tube (return artery) is also thermally connected to the heat sink. At intervals along their lengths, the condenser/vapor tube and the return artery are interconnected through porous plugs. This condenser configuration affords tolerance of freezing, variable effective thermal conductance (such that the return temperature remains nearly constant, independently of the ultimate sink temperature), and overall pressure drop smaller than it would be without the porous interconnections. An additional benefit of this configuration is that the condenser can be made to recover from the completely frozen condition either without using heaters, or else with the help of heaters much smaller than would otherwise be needed. The second condenser affords the same advantages and is based on a similar principle, but it has a different configuration that affords improved flow of working fluid, simplified construction, reduced weight, and faster recovery from a frozen condition.

Crowley, Christopher J.; Elkouhk, Nabil

2004-01-01

430

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

431

Bose-Einstein condensation of atoms in a uniform potential.  

PubMed

We have observed the Bose-Einstein condensation of an atomic gas in the (quasi)uniform three-dimensional potential of an optical box trap. Condensation is seen in the bimodal momentum distribution and the anisotropic time-of-flight expansion of the condensate. The critical temperature agrees with the theoretical prediction for a uniform Bose gas. The momentum distribution of a noncondensed quantum-degenerate gas is also clearly distinct from the conventional case of a harmonically trapped sample and close to the expected distribution in a uniform system. We confirm the coherence of our condensate in a matter-wave interference experiment. Our experiments open many new possibilities for fundamental studies of many-body physics. PMID:25167389

Gaunt, Alexander L; Schmidutz, Tobias F; Gotlibovych, Igor; Smith, Robert P; Hadzibabic, Zoran

2013-05-17

432

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

433

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

434

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

435

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

436

Slow dust in Enceladus' plume from condensation and wall collisions in tiger stripe fractures  

E-print Network

report a model for grain condensation and growth in channels of variable width. We show that repeated and condensation in cracks in Enceladus' ice shell. a, Schematic sketch. Gas escapes through channels of variable near the narrowest point of the channel (nozzle throat), where most grains nucleate. c, Profiles of gas

Potsdam, Universität

437

A combined condensing/vaporizing mechanism in the displacement of oil by enriched gases  

SciTech Connect

Experimental observations, combined with equation-of-state predictions, indicate that a combined condensing/vaporizing-gas drive mechanism, rather than the traditionally believed condensing-gas drive mechanism, may be responsible for displacements of reservoir oil by enriched gases. Apparent minimum miscibility pressures and minimum solvent enrichments are observed with this mechanism, even though true miscibility is probably not developed.

Zick, A.A.

1986-01-01

438

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

439

Thermocapillary flow with evaporation and condensation and its effect on liquid retention in low-G fluid acquisition devices  

NASA Technical Reports Server (NTRS)

The steady motion, thermal and free surface behavior of a volatile, wetting liquid in microgravity are studied using scaling and numerical techniques. The objective is to determine whether the thermocapillary and two-phase convection arising from thermodynamic nonequilibrium along the porous surfaces of spacecraft liquid acquisition devices could cause the retention failures observed with liquid hydrogen and heated vapor pressurant. Why these devices seem immune to retention loss when pressurized with heated helium or heated directly through the porous structure was also examined. Results show that highly wetting fluids exhibit large negative and positive dynamic pressure gradients towards the meniscus interline when superheated and subcooled, respectively. With superheating, the pressure variation and recoil force arising from liquid/vapor phase change exert the same influence on surface morphology and promote retention. With subcooling, however, the pressure distribution produces a suction that degrades mechanical equilibrium of the surface. This result indicates that thermocapillary-induced deformation arising from subcooling and condensation is the likely cause for retention loss. In addition, increasing the level of nonequilibrium by reducing accommodation coefficient suppresses deformation and explains why this failure mode does not occur in instances of direct screen heating or pressurization with a heated inert gas.

Schmidt, George R.

1994-01-01

440

Key condenser failure mechanisms  

SciTech Connect

Eight practical lessons highlight many of the factors that can influence condenser tube corrosion at coal-fired utilities and the effects contaminant in-leakage can have on steam generating units. 1 ref., 4 figs.

Buecker, B.

2009-04-15

441

Mechanism of dropwise condensation  

E-print Network

From a study of surface phenomena, information is obtained about conditions under which net condensation can occur. An experimental examination of the surface, using an optical method capable of detecting thin films of ...

Umur, Aydin

1963-01-01

442

THE COLOR GLASS CONDENSATE.  

SciTech Connect

The Color Glass Condensate is a state of high density gluonic matter which controls the high energy limit of hadronic interactions. Its properties are important for the initial conditions for matter produced at RHIC.

MCLERRAN,L.

2001-08-26

443

Infrared applications for steam turbine condenser systems  

NASA Astrophysics Data System (ADS)

Infrared inspection of the main steam condensers at the Peach Bottom Atomic Power Station has been utilized successfully in detecting condenser air in-leakage problems. Air in-leakage lowers the condenser's vacuum, thus decreasing the condenser's efficiency. This creates backpressure on the turbine which lowers its efficiency, resulting in fewer megawatts generated. Air in-leakage also creates an increase in off-gas flow which is a radiological concern for both the plant and the public. Inspections are normally performed on the condenser's manway covers and rupture disks prior to an outage during coast down and post outage. The optimum conditions are 100% power and temperature, however, a high radiation field prevents the inspection until reactor power is down to 65% or less. Anomalies are typically indicated by cooling in the effected areas of the air in-leakage. The anomalies are not limited to air in-leakage. Intermittent water out-leakage, due to a heater dump valve cycling, has been detected when visual inspections field nothing.

Lanius, Mark A.

2000-03-01

444

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

445

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

446

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

447

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

448

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

449

Measure Guideline: Evaporative Condensers  

SciTech Connect

The purpose of this measure guideline on evaporative condensers is to provide information on a cost-effective solution for energy and demand savings in homes with cooling loads. This is a prescriptive approach that outlines selection criteria, design and installation procedures, and operation and maintenance best practices. This document has been prepared to provide a process for properly designing, installing, and maintaining evaporative condenser systems as well as understanding the benefits, costs, and tradeoffs.

German, A.; Dakin, B.; Hoeschele, M.

2012-03-01

450

Open Problems in $?$ Particle Condensation  

E-print Network

$\\alpha$ particle condensation is a novel state in nuclear systems. We briefly review the present status on the study of $\\alpha$ particle condensation and address the open problems in this research field: $\\alpha$ particle condensation in heavier systems other than the Hoyle state, linear chain and $\\alpha$ particle rings, Hoyle-analogue states with extra neutrons, $\\alpha$ particle condensation related to astrophysics, etc.

Y. Funaki; M. Girod; H. Horiuchi; G. Roepke; P. Schuck; A. Tohsaki; T. Yamada

2010-03-05

451

Kinetics of mineral condensation in the solar nebula  

NASA Technical Reports Server (NTRS)

A natural extension of the type of gas-mineral-melt condensation experiments is to study the gas-mineral-melt reaction process by controlling the reaction times of appropriate gas compositions with silicate materials. In a condensing and vaporizing gas-solid system, important processes that could influence the composition of and speciation in the gas phase are the kinetics of vaporization of components from silicate crystals and melts. The high vacuum attainable in the space station would provide an environment for studying these processes at gas pressures much lower than those obtainable in experimental devices operated at terrestrial conditions in which the gas phase and mineral or melt would be allowed to come to exchange equilibrium. Further experiments would be performed at variable gas flow rates to simulate disequilibrium vapor fractionation. In this type of experiment it is desirable to analyze directly the species in the gas phase in equilibrium with the condensed silicate material. This analytical method would provide a direct determination of the species present in the gas phase. Currently, the notion of gas speciation is based on calculations from thermodynamic data. The proposed experiments require similar furnace designs and use similar experimental starting compositions, pressures, and temperatures as those described by Mysen.

Grove, T. L.

1987-01-01

452

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

453

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

454

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

455

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

456

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

457

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

458

US crude oil, natural gas, and natural gas liquids reserves  

SciTech Connect

This report presents estimates of proved reserves of crude oil, natural gas, and natural gas liquids as of December 31, 1989, and production volumes for the year 1989 for the total United States and for selected states and state sub-divisions. Estimates are presented for the following four categories of natural gas: total gas (wet after lease separation), its two major components (nonassociated and associated-dissolved gas), and total dry gas (wet gas adjusted for the removal of liquids at natural gas processing plants). In addition, two components of natural gas liquids, lease condensate and natural gas plant liquids, have their reserves and production reported separately. Also included is information on indicated additional crude oil reserves and crude oil, natural gas, and lease condensate reserves in nonproducing reservoirs. 28 refs., 9 figs., 15 tabs.

Not Available

1990-10-05

459

Condensate removal device for heat exchanger  

NASA Technical Reports Server (NTRS)

A set of perforated tubes disposed at the gas output side of a heat exchanger, in a position not to affect the rate of flow of the air or other gas is described. The tubes are connected to a common manifold which is connected to a sucking device. Where it is necessary to conserve and recirculate the air sucked through the tubes, the output of the manifold is run through a separator to remove the condensate from the gas. The perforations in the slurper tubes are small, lying in the range of 0.010 inch to 0.100 inch. The tubes are disposed in contact with the surfaces of the heat exchanger on which the condensate is precipitated, whether fins or plates, so that the water may be directed to the tube openings by means of surface effects, together with the assistance of the air flow. Only about 5 percent of the air output need be thus diverted, and it effectively removes virtually all of the condensate.

Trusch, R. B.; Oconnor, E. W. (inventors)

1975-01-01

460

Condensed Genome Structure  

PubMed Central

Large, tailed dsDNA-containing bacteriophage genomes are packaged to a conserved and high density (~500 mg/ml), generally in ~2.5-nm, duplex-to-duplex, spaced, organized DNA shells within icosahedral capsids. Phages with these condensate properties, however, differ markedly in their inner capsid structures: (1) those with a naked condensed DNA, (2) those with many dispersed unstructured proteins embedded within the DNA, (3) those with a small number of localized proteins, and (4) those with a reduced or DNA-free internal protein structure of substantial volume. The DNA is translocated and condensed by a high-force ATPase motor into a procapsid already containing the proteins that are to be ejected together with the DNA into the infected host. The condensed genome structure of a single-phage type is unlikely to be precisely determined and can change without loss of function to fit an altered capsid size or internal structure. Although no such single-phage condensed genome structure is known exactly, it is known that a single general structure is unlikely to apply to all such phages. PMID:22297527

Black, Lindsay W.

2013-01-01