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Sample records for high gas fractions

  1. Field tests of the high gas volume fraction multiphase meter

    SciTech Connect

    Tuss, B.; Perry, D.; Shoup, G.

    1996-12-31

    Tests were conducted during November, 1995 by Agar Corporation, Conoco, Inc., and Amoco Corporation at the Conoco Multiphase Test Facility near Lafayette, Louisiana, to demonstrate the performance of a novel high gas volume fraction multiphase meter. This paper describes how the meter works, summarizes the results of these field tests and discusses the application of the meter. The high gas volume fraction meter (MPFM-400 Series) utilizes a Fluidic Flow Diverter (FFD{trademark}) to divert most of the free gas in a multiphase stream around an MPFM-300 multiphase meter and into an ancillary gas measurement loop. The gas in the bypass loop is metered accurately and added to the oil, water, and gas measured by the multiphase meter. The result is a high void fraction multiphase meter which can accurately meter flow streams where the gas phase is a dominant component of the flow. This novel concept reduces the size and the cost of the multiphase meter while improving its capacity and accuracy. The field tests conducted at the Conoco Multiphase Test Facility have shown that the meter can handle flow conditions with the GOR of 20 to 90,000 SCF/BBL with very good accuracy. This paper describes the performance and accuracy of this new concept multiphase meter as demonstrated by the field tests. The MPFM400 Series Meter has important applications for metering high GOR wells or wells with moderate GOR that are tested at low pressure.

  2. Success grows in pumping high-gas-fraction multiphase fluids

    SciTech Connect

    Butler, B.

    1999-07-01

    Judging from the reports from user companies and discussions at the pump symposium following the 1999 Offshore Technology Conference, three kinds of pumps have now progressed to the point where they might be considered commercial and have demonstrated their ability to handle a variety of multiphase flows. These are twin screw, progressive cavity, and helico-axial (H-A) pumps. The twin-screw and progressive cavity (PC) pumps are positive displacement. They develop pressure hydrostatically and are less sensitive to density changes. The H-A type is a centrifugal pump which develops pressure dynamically and is highly sensitive to variation in density which is a characteristic of a multiphase flow stream. Now that the technical hurdles are better understood, it is time to look at economic viability. The close links between inlet pressure, gas volumes, and cost can be demonstrated and general cost relationships can be suggested. This discussion focuses on surface applications using twin-screw pumps that have the most applications and data highlighting actual field experience of major oil and gas companies who benefit from this type of multiphase technology.

  3. High-resolution fractionation after gas chromatography for effect-directed analysis.

    PubMed

    Pieke, Eelco; Heus, Ferry; Kamstra, Jorke H; Mladic, Marija; van Velzen, Martin; Kamminga, Dik; Lamoree, Marja H; Hamers, Timo; Leonards, Pim; Niessen, Wilfried M A; Kool, Jeroen

    2013-09-03

    This research presents an analytical technology for highly efficient, high-resolution, and high-yield fractionation of compounds after gas chromatography (GC) separations. The technology is straightforward, does not require sophisticated cold traps or adsorbent traps, and allows collecting large numbers of fractions during a GC run. The technology is based on direct infusion of a carrier solvent at the end of the GC column, where infusion takes place in the GC oven. Pentane and hexane used as carrier solvent showed good results. Acetonitrile also showed good results as a more polar carrier solvent. Development and optimization of the technology is described, followed by demonstration in a high-throughput effect directed analysis setting toward dioxin receptor bioactivity. The GC fractionation setup was capable of collecting fractions in the second range. As a result, fractionated compounds could be collected into one or two fractions when 6.5 s resolution fractionation was performed. Subsequently, mixtures containing polycyclic aromatic hydrocarbons, of which some are bioactive toward the dioxin receptor, were profiled with a mammalian gene reporter assay. After fractionation into 96-well plates, we used our new approach for direct cell seeding onto the fractions prior to assaying which allowed dioxin receptor bioactivity to be measured directly after fractionation. The current technology represents a great advance in effect directed analysis for environmental screening worldwide as it allows combining the preferred analytical separation technology for often non-polar environmental pollutants with environmentally relevant bioassays, in high resolution.

  4. Study on measures to improve gas-liquid phase mixing in a multiphase pump impeller under high gas void fraction

    NASA Astrophysics Data System (ADS)

    Zhang, J. Y.; Zhu, H. W.; Ding, K.; Qiang, R.

    2012-11-01

    Rotodynamic multiphase pump can transport crude gas-liquid mixture produced from oil well, and is regarded as the good choice of oil-gas multiphase transportation in offshore product system, for its advantages that compact structure, large flow rate, not sensitive to solid particles in the fluid. However, it is prone to bring about gas-liquid separation within the impeller under high gas void fraction. To solve the problem, this paper presents several measures to break gas packet and inhibit gas-liquid separation, such as, depositing the short blades, opening holes at the blades where gas packets gather, using T-shaped blades, etc. Then, CFD software was used to simulate the flow fields which were added measures to inhibit gas-liquid separation. The results show that streamlines in three new impellers distribute more evenly than in original impeller, the gas-liquid two phases mixed degree was improved, and the gas-liquid separation was inhibited to some extent. However, adding the short blades and using T-blade impeller failed to improve the differential pressure of impellers. So the placement and the geometrical parameters of the measures inhibiting gas-liquid separation should be further optimized.

  5. Theoretical and experimental analysis of a multiphase screw pump, handling gas-liquid mixtures with very high gas volume fractions

    SciTech Connect

    Raebiger, K.; Maksoud, T.M.A.; Ward, J.; Hausmann, G.

    2008-09-15

    In the investigation of the pumping behaviour of multiphase screw pumps, handling gas-liquid mixtures with very high gas volume fractions, theoretical and experimental analyses were performed. A new theoretical screw pump model was developed, which calculates the time-dependent conditions inside the several chambers of a screw pump as well as the exchange of mass and energy between these chambers. By means of the performed experimental analysis, the screw pump model was verified, especially at very high gas volume fractions from 90% to 99%. The experiments, which were conducted with the reference fluids water and air, can be divided mainly into the determination of the steady state pumping behaviour on the one hand and into the analysis of selected transient operating conditions on the other hand, whereas the visualisation of the leakage flows through the circumferential gaps was rounded off the experimental analysis. (author)

  6. Implementation of Ultrasonic Sensing for High Resolution Measurement of Binary Gas Mixture Fractions

    PubMed Central

    Bates, Richard; Battistin, Michele; Berry, Stephane; Bitadze, Alexander; Bonneau, Pierre; Bousson, Nicolas; Boyd, George; Bozza, Gennaro; Crespo-Lopez, Olivier; Riva, Enrico Da; Degeorge, Cyril; Deterre, Cecile; DiGirolamo, Beniamino; Doubek, Martin; Favre, Gilles; Godlewski, Jan; Hallewell, Gregory; Hasib, Ahmed; Katunin, Sergey; Langevin, Nicolas; Lombard, Didier; Mathieu, Michel; McMahon, Stephen; Nagai, Koichi; Pearson, Benjamin; Robinson, David; Rossi, Cecilia; Rozanov, Alexandre; Strauss, Michael; Vitek, Michal; Vacek, Vaclav; Zwalinski, Lukasz

    2014-01-01

    We describe an ultrasonic instrument for continuous real-time analysis of the fractional mixture of a binary gas system. The instrument is particularly well suited to measurement of leaks of a high molecular weight gas into a system that is nominally composed of a single gas. Sensitivity < 5 × 10−5 is demonstrated to leaks of octaflouropropane (C3F8) coolant into nitrogen during a long duration (18 month) continuous study. The sensitivity of the described measurement system is shown to depend on the difference in molecular masses of the two gases in the mixture. The impact of temperature and pressure variances on the accuracy of the measurement is analysed. Practical considerations for the implementation and deployment of long term, in situ ultrasonic leak detection systems are also described. Although development of the described systems was motivated by the requirements of an evaporative fluorocarbon cooling system, the instrument is applicable to the detection of leaks of many other gases and to processes requiring continuous knowledge of particular binary gas mixture fractions. PMID:24961217

  7. The Connection Between Reddening, Gas Covering Fraction, and the Escape of Ionizing Radiation at High Redshift

    NASA Astrophysics Data System (ADS)

    Reddy, Naveen A.; Steidel, Charles C.; Pettini, Max; Bogosavljević, Milan; Shapley, Alice E.

    2016-09-01

    Using a large sample of spectroscopically confirmed z∼ 3 galaxies, we establish an empirical relationship between reddening (E(B-V)), neutral gas covering fraction ({f}{{cov}}({{H}} {{I}})), and the escape of ionizing (Lyman continuum, LyC) photons. Our sample includes 933 galaxies at z∼ 3,121 of which have deep spectroscopic observations (≳ 7 hr) at 850≲ {λ }{{rest}}≲ 1300 Å with the Low Resolution Imaging Spectrograph on Keck. The high covering fraction of outflowing optically thick {{H}} {{I}} indicated by the composite spectra of these galaxies implies that photoelectric absorption, rather than dust attenuation, dominates the depletion of LyC photons. By modeling the composite spectra as the combination of an unattenuated stellar spectrum including nebular continuum emission with one that is absorbed by {{H}} {{I}} and reddened by a line-of-sight extinction, we derive an empirical relationship between E(B-V) and {f}{{cov}}({{H}} {{I}}). Galaxies with redder UV continua have larger covering fractions of {{H}} {{I}} characterized by higher line-of-sight extinctions. We develop a model which connects the ionizing escape fraction with E(B-V), and which may be used to estimate the ionizing escape fraction for an ensemble of galaxies. Alternatively, direct measurements of the escape fraction for our sample allow us to constrain the intrinsic LyC-to-UV flux density ratio to be < S(900 \\mathring{{A}} )/S(1500 \\mathring{{A}} ){> }{{int}}≳ 0.20, a value that favors stellar population models that include weaker stellar winds, a flatter initial mass function, and/or binary evolution. Last, we demonstrate how the framework discussed here may be used to assess the pathways by which ionizing radiation escapes from high-redshift galaxies. Based on data obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA, and was made possible by the generous

  8. High Dense Gas Fraction in a Gas-rich Star-forming Galaxy at z = 1.2

    NASA Astrophysics Data System (ADS)

    Gowardhan, Avani; Riechers, Dominik A.; Daddi, Emanuele; Pavesi, Riccardo; Dannerbauer, Helmut; Carilli, Chris

    2017-04-01

    We report observations of dense molecular gas in the star-forming galaxy EGS 13004291 (z = 1.197) using the Plateau de Bure Interferometer. We tentatively detect HCN and HNC J=2\\to 1 emission when stacked together at 4σ significance, yielding line luminosities of {L}{HCN(J=2\\to 1)}\\prime =(9+/- 3)× {10}9 K km s-1 pc2 and {L}{HNC(J=2\\to 1)}\\prime =(5+/- 2)× {10}9 K km s-1 pc2, respectively. We also set 3σ upper limits of <7-8 ×109 K km s-1 pc2 on the {{HCO}}+(J=2\\to 1), {{{H}}}2{{O}}({3}13\\to {2}20), and HC3N(J = 20 → 19) line luminosities. We serendipitously detect CO emission from two sources at z˜ 1.8 and z˜ 3.2 in the same field of view. We also detect CO(J=2\\to 1) emission in EGS 13004291, showing that the excitation in the previously detected CO(J=3\\to 2) line is subthermal ({r}32=0.65+/- 0.15). We find a line luminosity ratio of {L}{HCN}\\prime /{L}{CO}\\prime = 0.17 ± 0.07, as an indicator of the dense gas fraction. This is consistent with the median ratio observed in z> 1 galaxies ({L}{HCN}\\prime /{L}{CO}\\prime = 0.16 ± 0.07) and nearby ULIRGs ({L}{HCN}\\prime /{L}{CO}\\prime = 0.13 ± 0.03), but higher than that in local spirals ({L}{HCN}\\prime /{L}{CO}\\prime = 0.04 ± 0.02). Although EGS 13004291 lies significantly above the galaxy main sequence at z˜ 1, we do not find an elevated star formation efficiency (traced by {L}{FIR}/{L}{CO}\\prime ) as in local starbursts, but a value consistent with main-sequence galaxies. The enhanced dense gas fraction, the subthermal gas excitation, and the lower than expected star formation efficiency of the dense molecular gas in EGS 13004291 suggest that different star formation properties may prevail in high-z starbursts. Thus, using {L}{FIR}/{L}{CO}\\prime as a simple recipe to measure the star formation efficiency may be insufficient to describe the underlying mechanisms in dense star-forming environments inside the large gas reservoirs. Based on observations carried out under project ID U030

  9. Multiphase flowmeter measures three-phase flow at high gas volume fractions

    SciTech Connect

    1997-04-01

    A multiphase flowmeter (MPFM) installed offshore Egypt accurately measured three-phase flow in extremely gassy flow conditions. The meter is completely nonintrusive with no moving parts, requires no flow mixing before measurement and no bypass loop to remove gas before multiphase measurement. Flow regimes observed during the field test of this meter ranged from severe slugging to annular flow. Average gas volume fraction ranged from 93 to 98% during tests conducted on 7 wells. The meter was installed in the October field in the Gulf of Suez on a well-protector platform and was placed in series with a test separator located on a nearby production platform. Production was routed through both the MPFM and the test separator simultaneously. Flow conditions ranged from 1,300 to 4,700 B/D fluid, with 2.4 to 3.9 MMscf/D and water cuts from 1 to 52%. The MPFM measured gas and liquid rates to within {+-} 10% of test separator reference measurement flow rates at gas volume fractions from 93 to 96%. Accuracy deteriorated at higher gas volume fractions, but the meters provided repeatable results.

  10. High molecular gas fractions in normal massive star-forming galaxies in the young Universe.

    PubMed

    Tacconi, L J; Genzel, R; Neri, R; Cox, P; Cooper, M C; Shapiro, K; Bolatto, A; Bouché, N; Bournaud, F; Burkert, A; Combes, F; Comerford, J; Davis, M; Schreiber, N M Förster; Garcia-Burillo, S; Gracia-Carpio, J; Lutz, D; Naab, T; Omont, A; Shapley, A; Sternberg, A; Weiner, B

    2010-02-11

    Stars form from cold molecular interstellar gas. As this is relatively rare in the local Universe, galaxies like the Milky Way form only a few new stars per year. Typical massive galaxies in the distant Universe formed stars an order of magnitude more rapidly. Unless star formation was significantly more efficient, this difference suggests that young galaxies were much more molecular-gas rich. Molecular gas observations in the distant Universe have so far largely been restricted to very luminous, rare objects, including mergers and quasars, and accordingly we do not yet have a clear idea about the gas content of more normal (albeit massive) galaxies. Here we report the results of a survey of molecular gas in samples of typical massive-star-forming galaxies at mean redshifts of about 1.2 and 2.3, when the Universe was respectively 40% and 24% of its current age. Our measurements reveal that distant star forming galaxies were indeed gas rich, and that the star formation efficiency is not strongly dependent on cosmic epoch. The average fraction of cold gas relative to total galaxy baryonic mass at z = 2.3 and z = 1.2 is respectively about 44% and 34%, three to ten times higher than in today's massive spiral galaxies. The slow decrease between z approximately 2 and z approximately 1 probably requires a mechanism of semi-continuous replenishment of fresh gas to the young galaxies.

  11. Noble gas fractionation during subsurface gas migration

    NASA Astrophysics Data System (ADS)

    Sathaye, Kiran J.; Larson, Toti E.; Hesse, Marc A.

    2016-09-01

    Environmental monitoring of shale gas production and geological carbon dioxide (CO2) storage requires identification of subsurface gas sources. Noble gases provide a powerful tool to distinguish different sources if the modifications of the gas composition during transport can be accounted for. Despite the recognition of compositional changes due to gas migration in the subsurface, the interpretation of geochemical data relies largely on zero-dimensional mixing and fractionation models. Here we present two-phase flow column experiments that demonstrate these changes. Water containing a dissolved noble gas is displaced by gas comprised of CO2 and argon. We observe a characteristic pattern of initial co-enrichment of noble gases from both phases in banks at the gas front, followed by a depletion of the dissolved noble gas. The enrichment of the co-injected noble gas is due to the dissolution of the more soluble major gas component, while the enrichment of the dissolved noble gas is due to stripping from the groundwater. These processes amount to chromatographic separations that occur during two-phase flow and can be predicted by the theory of gas injection. This theory provides a mechanistic basis for noble gas fractionation during gas migration and improves our ability to identify subsurface gas sources after post-genetic modification. Finally, we show that compositional changes due to two-phase flow can qualitatively explain the spatial compositional trends observed within the Bravo Dome natural CO2 reservoir and some regional compositional trends observed in drinking water wells overlying the Marcellus and Barnett shale regions. In both cases, only the migration of a gas with constant source composition is required, rather than multi-stage mixing and fractionation models previously proposed.

  12. ALMA Observations of Gas-rich Galaxies in z ˜ 1.6 Galaxy Clusters: Evidence for Higher Gas Fractions in High-density Environments

    NASA Astrophysics Data System (ADS)

    Noble, A. G.; McDonald, M.; Muzzin, A.; Nantais, J.; Rudnick, G.; van Kampen, E.; Webb, T. M. A.; Wilson, G.; Yee, H. K. C.; Boone, K.; Cooper, M. C.; DeGroot, A.; Delahaye, A.; Demarco, R.; Foltz, R.; Hayden, B.; Lidman, C.; Manilla-Robles, A.; Perlmutter, S.

    2017-06-01

    We present ALMA CO (2-1) detections in 11 gas-rich cluster galaxies at z ˜ 1.6, constituting the largest sample of molecular gas measurements in z > 1.5 clusters to date. The observations span three galaxy clusters, derived from the Spitzer Adaptation of the Red-sequence Cluster Survey. We augment the >5σ detections of the CO (2-1) fluxes with multi-band photometry, yielding stellar masses and infrared-derived star formation rates, to place some of the first constraints on molecular gas properties in z ˜ 1.6 cluster environments. We measure sizable gas reservoirs of 0.5-2 × 1011 M ⊙ in these objects, with high gas fractions (f gas) and long depletion timescales (τ), averaging 62% and 1.4 Gyr, respectively. We compare our cluster galaxies to the scaling relations of the coeval field, in the context of how gas fractions and depletion timescales vary with respect to the star-forming main sequence. We find that our cluster galaxies lie systematically off the field scaling relations at z = 1.6 toward enhanced gas fractions, at a level of ˜4σ, but have consistent depletion timescales. Exploiting CO detections in lower-redshift clusters from the literature, we investigate the evolution of the gas fraction in cluster galaxies, finding it to mimic the strong rise with redshift in the field. We emphasize the utility of detecting abundant gas-rich galaxies in high-redshift clusters, deeming them as crucial laboratories for future statistical studies.

  13. Enhanced diesel fuel fraction from waste high-density polyethylene and heavy gas oil pyrolysis using factorial design methodology.

    PubMed

    Joppert, Ney; da Silva, Alexsandro Araujo; da Costa Marques, Mônica Regina

    2015-02-01

    Factorial Design Methodology (FDM) was developed to enhance diesel fuel fraction (C9-C23) from waste high-density polyethylene (HDPE) and Heavy Gas Oil (HGO) through co-pyrolysis. FDM was used for optimization of the following reaction parameters: temperature, catalyst and HDPE amounts. The HGO amount was constant (2.00 g) in all experiments. The model optimum conditions were determined to be temperature of 550 °C, HDPE = 0.20 g and no FCC catalyst. Under such conditions, 94% of pyrolytic oil was recovered, of which diesel fuel fraction was 93% (87% diesel fuel fraction yield), no residue was produced and 6% of noncondensable gaseous/volatile fraction was obtained. Seeking to reduce the cost due to high process temperatures, the impact of using higher catalyst content (25%) with a lower temperature (500 °C) was investigated. Under these conditions, 88% of pyrolytic oil was recovered (diesel fuel fraction yield was also 87%) as well as 12% of the noncondensable gaseous/volatile fraction. No waste was produced in these conditions, being an environmentally friendly approach for recycling the waste plastic. This paper demonstrated the usefulness of using FDM to predict and to optimize diesel fuel fraction yield with a great reduction in the number of experiments.

  14. Calculation of the pressure vessel failure fraction of fuel particle of gas turbine high temperature reactor 300 C

    SciTech Connect

    Aihara, J.; Ueta, S.; Mozumi, Y.; Sato, H.; Sawa, K.; Motohashi, Y.

    2007-07-01

    In high temperature gas-cooled reactors (HTGRs), coated particles are used as fuels. For upgrading HTGR technologies, present SiC coating layer which is used as the 3. layer could be replaced with ZrC coating layer which have much higher temperature stability in addition to higher resistance to chemical attack by fission product palladium than the SiC coating layer. The ZrC layer could deform plastically at high temperatures. Therefore, the Japan Atomic Energy Agency modified an existing pressure vessel failure fraction calculation code to treat the plastic deformation of the 3. layer in order to predict failure fraction of ZrC coated particle under irradiation. Finite element method is employed to calculate the stress in each coating layer. The pressure vessel failure fraction of the coated fuel particles under normal operating condition of GTHTR300C is calculated by the modified code. The failure fraction is evaluated as low as 3.5 x 10{sup -6}. (authors)

  15. Multiphase flowmeter successfully measures three-phase flow at extremely high gas-volume fractions -- Gulf of Suez, Egypt

    SciTech Connect

    Leggett, R.B.; Borling, D.C.; Powers, B.S.; Shehata, K.; Halvorsen, M.

    1998-02-01

    A multiphase flowmeter (MPFM) installed in offshore Egypt has accurately measured three-phase flow in extremely gassy flow conditions. The meter is completely nonintrusive, with no moving parts, requires no flow mixing before measurement, and has no bypass loop to remove gas before multiphase measurement. Flow regimes observed during the field test of this meter ranged from severe slugging to annular flow caused by the dynamics of gas-lift gas in the production stream. Average gas-volume fraction ranged from 93 to 98% during tests conducted on seven wells. The meter was installed in the Gulf of Suez on a well protector platform in the Gulf of Suez Petroleum Co. (Gupco) October field, and was placed in series with a test separator located on a nearby production platform. Wells were individually tested with flow conditions ranging from 1,300 to 4,700 B/D fluid, 2.4 to 3.9 MMscf/D of gas, and water cuts from 1 to 52%. The meter is capable of measuring water cuts up to 100%. Production was routed through both the MPFM and the test separator simultaneously as wells flowed with the assistance of gas-lift gas. The MPFM measured gas and liquid rates to within {+-} 10% of test-separator reference measurement flow rates, and accomplished this at gas-volume fractions from 93 to 96%. At higher gas-volume fractions up to 98%, accuracy deteriorated but the meter continued to provide repeatable results.

  16. A high gas fraction, reduced power, syngas bioprocessing method demonstrated with a Clostridium ljungdahlii OTA1 paper biocomposite.

    PubMed

    Schulte, Mark J; Wiltgen, Jeff; Ritter, John; Mooney, Charles B; Flickinger, Michael C

    2016-09-01

    We propose a novel approach to continuous bioprocessing of gases. A miniaturized, coated-paper strip, high gas fraction, biocomposite absorber has been developed using slowly shaken horizontal anaerobic tubes. Concentrated Clostridium ljungdahlii OTA1 was used as a model system. These gas absorbers demonstrate elevated CO mass transfer with low power input, reduced liquid requirements, elevated substrate consumption, and increased product secretion compared to shaken suspended cells. Concentrated OTA1 cell paste was coated by extrusion onto chromatography paper. The immobilized system shows high, constant reactivity immediately upon rehydration. Cell adhesion was by adsorption to the cellulose fibers; visualized by SEM. The C. ljungdahlii OTA1 coated paper mounted above the liquid level absorbs CO and H2 from a model syngas secreting acetate with minimal ethanol. At 100 rpm shaking speed (7.7 Wm(-3) ) the optimal cell loading is 6.5 gDCW m(-2) to maintain high CO absorbing reactivity without the cells coming off of the paper into the liquid phase. Reducing the medium volume from 10 mL to 4 mL (15% of tube volume) did not decrease CO reactivity. The reduced liquid volume increased secreted product concentration by 80%. The specific CO consumption by paper biocomposites was higher at all shaking frequencies <100 rpm than suspended cells under identical incubation conditions. At 25 rpm the biocomposite outperforms suspended cells for CO absorption by 2.5-fold, with an estimated power reduction of 97% over the power input at 100 rpm. The estimated minimum kL a for miniaturized biocomposite gas-absorbers is ∼100 h(-1) , 10 to 10(4) less power input than other syngas fermentation systems reported in the literature at similar kL a. Specific consumption rates in a biocomposite were ∼14 mmol gDCW-1 h(-1) . This work intensified CO absorption and reactivity by 14-fold to 94 mmol CO m(-2) h(-1) over previous C. ljungdahlii OTA1 work by our group

  17. Gas chromatography fractionation platform featuring parallel flame-ionization detection and continuous high-resolution analyte collection in 384-well plates.

    PubMed

    Jonker, Willem; Clarijs, Bas; de Witte, Susannah L; van Velzen, Martin; de Koning, Sjaak; Schaap, Jaap; Somsen, Govert W; Kool, Jeroen

    2016-09-02

    Gas chromatography (GC) is a superior separation technique for many compounds. However, fractionation of a GC eluate for analyte isolation and/or post-column off-line analysis is not straightforward, and existing platforms are limited in the number of fractions that can be collected. Moreover, aerosol formation may cause serious analyte losses. Previously, our group has developed a platform that resolved these limitations of GC fractionation by post-column infusion of a trap solvent prior to continuous small-volume fraction collection in a 96-wells plate (Pieke et al., 2013 [17]). Still, this GC fractionation set-up lacked a chemical detector for the on-line recording of chromatograms, and the introduction of trap solvent resulted in extensive peak broadening for late-eluting compounds. This paper reports advancements to the fractionation platform allowing flame ionization detection (FID) parallel to high-resolution collection of a full GC chromatograms in up to 384 nanofractions of 7s each. To this end, a post-column split was incorporated which directs part of the eluate towards FID. Furthermore, a solvent heating device was developed for stable delivery of preheated/vaporized trap solvent, which significantly reduced band broadening by post-column infusion. In order to achieve optimal analyte trapping, several solvents were tested at different flow rates. The repeatability of the optimized GC fraction collection process was assessed demonstrating the possibility of up-concentration of isolated analytes by repetitive analyses of the same sample. The feasibility of the improved GC fractionation platform for bioactivity screening of toxic compounds was studied by the analysis of a mixture of test pesticides, which after fractionation were subjected to a post-column acetylcholinesterase (AChE) assay. Fractions showing AChE inhibition could be unambiguously correlated with peaks from the parallel-recorded FID chromatogram. Copyright © 2016 Elsevier B.V. All rights

  18. The effects of 2 levels of the inspired oxygen fraction on blood gas variables in propofol-anesthetized dogs with high intracranial pressure

    PubMed Central

    Dias, Luis Gustavo Gosuen Gonçalves; Nunes, Newton; Lopes, Patrícia Cristina Ferro; de Almeida, Ricardo Miyasaka; Neto, Gláucia Bueno Pereira; de Souza, Ana Letícia Groszewicz; de Almeida Belmonte, Emílio

    2009-01-01

    The influence of 2 different levels of the inspired oxygen fraction (FiO2) on blood gas variables was evaluated in dogs with high intracranial pressure (ICP) during propofol anesthesia (induction followed by a continuous rate infusion [CRI] of 0.6 mg/kg/min) and intermittent positive pressure ventilation (IPPV). Eight adult mongrel dogs were anesthetized on 2 occasions, 21 d apart, and received oxygen at an FiO2 of 1.0 (G100) or 0.6 (G60) in a randomized crossover fashion. A fiberoptic catheter was implanted on the surface of the right cerebral cortex for assessment of the ICP. An increase in the ICP was induced by temporary ligation of the jugular vein 50 min after induction of anesthesia and immediately after baseline measurement of the ICP. Blood gas measurements were taken 20 min later and then at 15-min intervals for 1 h. Numerical data were submitted to Morrison’s multivariate statistical methods. The ICP, the cerebral perfusion pressure and the mean arterial pressure did not differ significantly between FiO2 levels or measurement times after jugular ligation. The only blood gas values that differed significantly (P < 0.05) were the arterial oxygen partial pressure, which was greater with G100 than with G60 throughout the procedure, and the venous haemoglobin saturation, that was greater with G100 than with G60 at M0. There were no significant differences between FiO2 levels or measurement times in the following blood gas variables: arterial carbon dioxide partial pressure, arterial hemoglobin saturation, base deficit, bicarbonate concentration, pH, venous oxygen partial pressure, venous carbon dioxide partial pressure and the arterial-to-end-tidal carbon dioxide difference. PMID:19436579

  19. THE UNIVERSAL GAS MASS FRACTION IN CLUSTERS OF GALAXIES

    SciTech Connect

    David, Laurence P.; Jones, Christine; Forman, William

    2012-04-01

    We obtained a deep 150 ks Chandra observation of the optically selected cluster of galaxies, RCS 2318+0034, to investigate the gas mass fraction in this system. Combining our deep Chandra observation with an archival 50 ks observation, we derive gas mass fractions of f{sub gas} = 0.06 {+-} .02 and 0.10 {+-} .02 within r{sub 2500} and r{sub 500}, respectively. The gas mass fraction in RCS 2318+0034 within r{sub 500} is typical of X-ray-selected clusters. Further study shows that the large-scale properties of RCS 2318+0034, including the relations between gas mass, X-ray luminosity, and gas temperature, are also consistent with the observed correlations of X-ray-selected clusters. However, the gas mass fraction within r{sub 2500} is less than most X-ray-selected clusters, as previously reported. The deep Chandra image of RCS 2318+0034 shows that this system is currently undergoing a major merger which may have an impact on the inferred gas mass fraction within r{sub 2500}.

  20. The effect of gas fraction on centrifugal pump

    NASA Astrophysics Data System (ADS)

    Zhu, Z. T.; Wang, Y.; Zhao, L. F.; Ning, C.; Xie, S. F.; Liu, Z. C.

    2015-01-01

    In order to study the multiphase flow field in M125 centrifugal pump, three-dimensional modeling was used for internal flow through three-dimensional software Pro/E. Then based on SST turbulence model combining with Rayleigh-Plesset cavitation model, and structured grid to simulate the hydraulic characteristics of volute and impeller within different gas conditions. The velocity, pressure and gas volume fraction distributions of the interior flow field of volute and impeller were obtained and analyzed, which revealed the effect of gas fractions on the flow characteristic of the centrifugal pump.

  1. Noble gas trapping and fractionation during synthesis of carbonaceous matter. [in meteorites

    NASA Technical Reports Server (NTRS)

    Frick, U.; Mack, R.; Chang, S.

    1979-01-01

    An investigation of noble gas entrapment during synthesis of carbonaceous, macromolecular, and kerogen-like substances is presented. High molecular weight organic matter synthesized in aqueous condensation reactions contained little gas, and the composition was consistent with fractionation due to noble gas solubility in water; however, propane soot produced during a modified Miller-Urey experiment in an aritificial gas mixture contained high concentrations of trapped noble gases that displayed strong elemental fractionation from their reservoirs. It is concluded that theses experiemnts show that processes exist for synthesis of carbonaceous carriers that result in high noble gas concentrations and strong elemental fractionation at temperatures well above those required by absorption to achieve similar effects.

  2. Noble gas trapping and fractionation during synthesis of carbonaceous matter. [in meteorites

    NASA Technical Reports Server (NTRS)

    Frick, U.; Mack, R.; Chang, S.

    1979-01-01

    An investigation of noble gas entrapment during synthesis of carbonaceous, macromolecular, and kerogen-like substances is presented. High molecular weight organic matter synthesized in aqueous condensation reactions contained little gas, and the composition was consistent with fractionation due to noble gas solubility in water; however, propane soot produced during a modified Miller-Urey experiment in an aritificial gas mixture contained high concentrations of trapped noble gases that displayed strong elemental fractionation from their reservoirs. It is concluded that theses experiemnts show that processes exist for synthesis of carbonaceous carriers that result in high noble gas concentrations and strong elemental fractionation at temperatures well above those required by absorption to achieve similar effects.

  3. Experimental studies and model analysis of noble gas fractionation in low-permeability porous media

    NASA Astrophysics Data System (ADS)

    Ding, Xin; Mack Kennedy, B.; Molins, Sergi; Kneafsey, Timothy; Evans, William C.

    2017-05-01

    Gas flow through the vadose zone from sources at depth involves fractionation effects that can obscure the nature of transport and even the identity of the source. Transport processes are particularly complex in low permeability media but as shown in this study, can be elucidated by measuring the atmospheric noble gases. A series of laboratory column experiments was conducted to evaluate the movement of noble gas from the atmosphere into soil in the presence of a net efflux of CO2, a process that leads to fractionation of the noble gases from their atmospheric abundance ratios. The column packings were designed to simulate natural sedimentary deposition by interlayering low permeability ceramic plates and high permeability beach sand. Gas samples were collected at different depths at CO2 fluxes high enough to cause extreme fractionation of the noble gases (4He/36Ar > 20 times the air ratio). The experimental noble gas fractionation-depth profiles were in good agreement with those predicted by the dusty gas (DG) model, demonstrating the applicability of the DG model across a broad spectrum of environmental conditions. A governing equation based on the dusty gas model was developed to specifically describe noble gas fractionation at each depth that is controlled by the binary diffusion coefficient, Knudsen diffusion coefficient and the ratio of total advection flux to total flux. Finally, the governing equation was used to derive the noble gas fractionation pattern and illustrate how it is influenced by soil CO2 flux, sedimentary sequence, thickness of each sedimentary layer and each layer's physical parameters. Three potential applications of noble gas fractionation are provided: evaluating soil attributes in the path of gas flow from a source at depth to the atmosphere, testing leakage through low permeability barriers used to isolate buried waste, and tracking biological methanogenesis and methane oxidation associated with hydrocarbon degradation.

  4. High Velocity Gas Gun

    NASA Technical Reports Server (NTRS)

    1988-01-01

    A video tape related to orbital debris research is presented. The video tape covers the process of loading a High Velocity Gas Gun and firing it into a mounted metal plate. The process is then repeated in slow motion.

  5. High Velocity Gas Gun

    NASA Technical Reports Server (NTRS)

    1988-01-01

    A video tape related to orbital debris research is presented. The video tape covers the process of loading a High Velocity Gas Gun and firing it into a mounted metal plate. The process is then repeated in slow motion.

  6. Comparison between pre-fractionation and fractionation process of heavy gas oil for determination of sulfur compounds using comprehensive two-dimensional gas chromatography.

    PubMed

    Machado, Maria Elisabete; Bregles, Lucas Panizzi; de Menezes, Eliana Weber; Caramão, Elina Bastos; Benvenutti, Edilson Valmir; Zini, Cláudia Alcaraz

    2013-01-25

    The separation of the organic sulfur compounds (OSC) of petroleum or its heavy fractions is a critical step and is essential for the correct characterization of these compounds, especially due to similar physical and chemical properties of polycyclic aromatic sulfur heterocycles (PASH) and polycyclic aromatic hydrocarbons (PAH). This similarity results in coelutions among PAH and PASH and for this reason former steps of fractionation are required before gas chromatographic analysis. The objective of this study was to evaluate the potential of GC×GC for the separation and identification of OSC in a heavy gas oil sample without fractionation, after pre-fractionation in an alumina column and also after fractionation process. This last one was performed with a modified stationary phase manufactured and characterized in the laboratory, called Pd(II)-MPSG, where palladium is chemically linked to silica through mercaptopropyl groups. The fractions obtained from both procedures were analyzed by GC×GC/TOFMS, which was effective to separate and identify various classes of OSC. A hundred and thirty-five compounds were tentatively identified in the sample that was only pre-fractionated. However, when the fractionation was also performed with the Pd(II)-MPSG phase, a larger number of sulfur compounds were found (317). Results have shown that the analysis of a pre-fractionated sample by GC×GC/TOFMS is suitable when the goal is a general characterization of classes of compounds in the sample, while a more detailed analysis of PASH can be performed, using also the fractionation Pd(II)-MPSG phase. GC×GC/TOFMS played a major role in the comparison of samples obtained from pre-fractionation and fractionation steps due to its high peak capacity, selectivity, organized distribution of chromatographic peaks and resolution.

  7. High Throughput In Situ DDA Analysis of Neuropeptides by Coupling Novel Multiplex Mass Spectrometric Imaging (MSI) with Gas-Phase Fractionation

    NASA Astrophysics Data System (ADS)

    OuYang, Chuanzi; Chen, Bingming; Li, Lingjun

    2015-12-01

    Matrix-assisted laser desorption/ionization (MALDI) mass spectrometric imaging (MSI) is a powerful tool to map the spatial distribution of biomolecules on tissue sections. Recent developments of hybrid MS instruments allow combination of different types of data acquisition by various mass analyzers into a single MSI analysis, which reduces experimental time and sample consumptions. Here, using the well-characterized crustacean nervous system as a test-bed, we explore the utility of high resolution and accurate mass (HRAM) MALDI Orbitrap platform for enhanced in situ characterization of the neuropeptidome with improved chemical information. Specifically, we report on a multiplex-MSI method, which combines HRAM MSI with data dependent acquisition (DDA) tandem MS analysis in a single experiment. This method enables simultaneous mapping of neuropeptide distribution, sequence validation, and novel neuropeptide discovery in crustacean neuronal tissues. To enhance the dynamic range and efficiency of in situ DDA, we introduced a novel approach of fractionating full m/z range into several sub-mass ranges and embedding the setup using the multiplex-DDA-MSI scan events to generate pseudo fractionation before MS/MS scans. The division of entire m/z into multiple segments of m/z sub-ranges for MS interrogation greatly decreased the complexity of molecular species from tissue samples and the heterogeneity of the distribution and variation of intensities of m/z peaks. By carefully optimizing the experimental conditions such as the dynamic exclusion, the multiplex-DDA-MSI approach demonstrates better performance with broader precursor coverage, less biased MS/MS scans towards high abundance molecules, and improved quality of tandem mass spectra for low intensity molecular species.

  8. High Throughput In Situ DDA Analysis of Neuropeptides by Coupling Novel Multiplex Mass Spectrometric Imaging (MSI) with Gas-Phase Fractionation.

    PubMed

    OuYang, Chuanzi; Chen, Bingming; Li, Lingjun

    2015-12-01

    Matrix-assisted laser desorption/ionization (MALDI) mass spectrometric imaging (MSI) is a powerful tool to map the spatial distribution of biomolecules on tissue sections. Recent developments of hybrid MS instruments allow combination of different types of data acquisition by various mass analyzers into a single MSI analysis, which reduces experimental time and sample consumptions. Here, using the well-characterized crustacean nervous system as a test-bed, we explore the utility of high resolution and accurate mass (HRAM) MALDI Orbitrap platform for enhanced in situ characterization of the neuropeptidome with improved chemical information. Specifically, we report on a multiplex-MSI method, which combines HRAM MSI with data dependent acquisition (DDA) tandem MS analysis in a single experiment. This method enables simultaneous mapping of neuropeptide distribution, sequence validation, and novel neuropeptide discovery in crustacean neuronal tissues. To enhance the dynamic range and efficiency of in situ DDA, we introduced a novel approach of fractionating full m/z range into several sub-mass ranges and embedding the setup using the multiplex-DDA-MSI scan events to generate pseudo fractionation before MS/MS scans. The division of entire m/z into multiple segments of m/z sub-ranges for MS interrogation greatly decreased the complexity of molecular species from tissue samples and the heterogeneity of the distribution and variation of intensities of m/z peaks. By carefully optimizing the experimental conditions such as the dynamic exclusion, the multiplex-DDA-MSI approach demonstrates better performance with broader precursor coverage, less biased MS/MS scans towards high abundance molecules, and improved quality of tandem mass spectra for low intensity molecular species. Graphical Abstract ᅟ.

  9. HIGH PRESSURE GAS REGULATOR

    DOEpatents

    Ramage, R.W.

    1962-05-01

    A gas regulator operating on the piston and feedback principle is described. The device is particularly suitable for the delicate regulation of high pressure, i.e., 10,000 psi and above, gas sources, as well as being perfectly adaptable for use on gas supplies as low as 50 psi. The piston is adjustably connected to a needle valve and the movement of the piston regulates the flow of gas from the needle valve. The gas output is obtained from the needle valve. Output pressure is sampled by a piston feedback means which, in turn, regulates the movement of the main piston. When the output is other than the desired value, the feedback system initiates movement of the main piston to allow the output pressure to be corrected or to remain constant. (AEC)

  10. Constraining the Fraction of Dense Gas in the Galactic Center

    NASA Astrophysics Data System (ADS)

    Mills, Elisabeth A.; Ginsburg, Adam; Barnes, Jonathan; Morris, Mark; Wiesenfeld, Laurent; Faure, Alexandre

    2016-01-01

    The central 500 parsecs of the Milky Way-- the Central Molecular Zone or CMZ-- is one of the most extreme environments for molecular gas in our Galaxy. Recent studies have suggested that the star formation relations in this region are anomalous, with less star formation per unit dense (n > 10^4 cm^-3) gas than is seen elsewhere in the universe. While this would be an exciting result indicating that star formation may proceed differently as a function of environment, it must be verified that it is not an effect of either undercounting the amount of star formation, or overestimating the bulk gas density in this region. CMZ gas densities in particular have not been revisited in several decades, and have only been measured accurately for a small handful of clouds in this region. We address this deficiency by presenting updated gas densities for a sample of 10 of the most massive molecular clouds in the CMZ. We use the Robert C. Byrd Green Bank Telescope, MOPRA, and APEX to measure lines of HC3N from J = 3-2 to J=30-29, and then perform radiative transfer analysis to constrain gas densities. We find that typical gas densities are somewhat lower than previously indicated, and present the first constraints on the fraction of gas with n >10^5 cm^-3 for multiple clouds in this region.

  11. Extreme Gas Fractions in Clumpy, Turbulent Disk Galaxies at z ~ 0.1

    NASA Astrophysics Data System (ADS)

    Fisher, David B.; Glazebrook, Karl; Bolatto, Alberto; Obreschkow, Danail; Mentuch Cooper, Erin; Wisnioski, Emily; Bassett, Robert; Abraham, Roberto G.; Damjanov, Ivana; Green, Andy; McGregor, Peter

    2014-08-01

    In this Letter, we report the discovery of CO fluxes, suggesting very high gas fractions in three disk galaxies seen in the nearby universe (z ~ 0.1). These galaxies were investigated as part of the DYnamics of Newly Assembled Massive Objects (DYNAMO) survey. High-resolution Hubble Space Telescope imaging of these objects reveals the presence of large star forming clumps in the bodies of the galaxies, while spatially resolved spectroscopy of redshifted Hα reveals the presence of high dispersion rotating disks. The internal dynamical state of these galaxies resembles that of disk systems seen at much higher redshifts (1 < z < 3). Using CO(1-0) observations made with the Plateau de Bure Interferometer, we find gas fractions of 20%-30% and depletion times of t dep ~ 0.5 Gyr (assuming a Milky-Way-like αCO). These properties are unlike those expected for low-redshift galaxies of comparable specific star formation rate, but they are normal for their high-z counterparts. DYNAMO galaxies break the degeneracy between gas fraction and redshift, and we show that the depletion time per specific star formation rate for galaxies is closely tied to gas fraction, independent of redshift. We also show that the gas dynamics of two of our local targets corresponds to those expected from unstable disks, again resembling the dynamics of high-z disks. These results provide evidence that DYNAMO galaxies are local analogs to the clumpy, turbulent disks, which are often found at high redshift.

  12. Molecular gas during the post-starburst phase: low gas fractions in green-valley Seyfert post-starburst galaxies

    NASA Astrophysics Data System (ADS)

    Yesuf, Hassen M.; French, K. Decker; Faber, S. M.; Koo, David C.

    2017-08-01

    Post-starbursts (PSBs) are candidate for rapidly transitioning from starbursting to quiescent galaxies. We study the molecular gas evolution of PSBs at z ∼ 0.03-0.2. We undertook new CO (2-1) observations of 22 Seyfert PSB candidates using the Arizona Radio Observatory Submillimeter Telescope. This sample complements previous samples of PSBs by including green-valley PSBs with Seyfert-like emission, allowing us to analyse for the first time the molecular gas properties of 116 PSBs with a variety of AGN properties. The distribution of molecular gas to stellar mass fractions in PSBs is significantly different from normal star-forming galaxies in the CO Legacy Database (COLD) GASS survey. The combined samples of PSBs with Seyfert-like emission line ratios have a gas fraction distribution that is even more significantly different and is broader (∼0.03-0.3). Most of them have lower gas fractions than normal star-forming galaxies. We find a highly significant correlation between the WISE 12 and 4.6 μm flux ratios and molecular gas fractions in both PSBs and normal galaxies. We detect molecular gas in 27 per cent of our Seyfert PSBs. Taking into account the upper limits, the mean and the dispersion of the distribution of the gas fraction in our Seyfert PSB sample are much smaller (μ = 0.025, σ = 0.018) than previous samples of Seyfert PSBs or PSBs in general (μ ∼ 0.1-0.2, σ ∼ 0.1-0.2).

  13. Gas phase fractionation method using porous ceramic membrane

    DOEpatents

    Peterson, Reid A.; Hill, Jr., Charles G.; Anderson, Marc A.

    1996-01-01

    Flaw-free porous ceramic membranes fabricated from metal sols and coated onto a porous support are advantageously used in gas phase fractionation methods. Mean pore diameters of less than 40 .ANG., preferably 5-20 .ANG. and most preferably about 15 .ANG., are permeable at lower pressures than existing membranes. Condensation of gases in small pores and non-Knudsen membrane transport mechanisms are employed to facilitate and increase membrane permeability and permselectivity.

  14. Characterization and quantification of the hydrocarbons fraction of the subcutaneous fresh fat of Iberian pig by off-line combination of high performance liquid chromatography and gas chromatography.

    PubMed

    Gamero-Pasadas, A; Viera Alcaide, I; Rios, J J; Graciani Constante, E; Vicario, I M; León-Camacho, M

    2006-08-04

    Hydrocarbons in fresh subcutaneous fat of Iberian pig have been analyzed by GC-MS after fractionation of the unsaponifiable fraction with a new off-line combination of HPLC and GC method. The new method proposed improves the recovery and simultaneous quantification of terpenic hydrocarbons in comparison to the traditional LC method. When necessary and for identification purposes, selective ion monitoring (SIM) was used as acquisition mode in GC-MS. To determine the position of the double bonds in the unsaturated hydrocarbon chain the dimethyl disulfide derivatives (DMDS) were obtained. To elucidate the structure of the branched 1-alkenes the hydrocarbon fraction was submitted to hydrogenation. Thirty-five compounds have been identified, including n-alkanes, n-alkenes, branched (n-1,n-2-dimethyl-1-alkenes) and terpenic hydrocarbons, being the most abundant n-alkenes and n-alkanes of even chain of n-C12-n-C26. Besides the hydrocarbons already described in bibliography, a new diterpenic hydrocarbon, ent-kaurene, have been identified for the first time. The compound reported as Neophytadiene by other authors, has been identified as a 20 atoms hydrocarbon with two double bonds, the 7,11,15-trimethyl-heptadeca-1,4-diene.

  15. The dense gas mass fraction of molecular clouds in the Milky Way

    SciTech Connect

    Battisti, Andrew J.; Heyer, Mark H. E-mail: heyer@astro.umass.edu

    2014-01-10

    The mass fraction of dense gas within giant molecular clouds (GMCs) of the Milky Way is investigated using {sup 13}CO data from the Five College Radio Astronomy Observatory Galactic Plane Surveys and the Bolocam Galactic Plane Survey (BGPS) of 1.1 mm dust continuum emission. A sample of 860 compact dust sources are selected from the BGPS catalog and kinematically linked to 344 clouds of extended (>3') {sup 13}CO J = 1-0 emission. Gas masses are tabulated for the full dust source and subregions within the dust sources with mass surface densities greater than 200 M {sub ☉} pc{sup –2}, which are assumed to be regions of enhanced volume density. Masses of the parent GMCs are calculated assuming optically thin {sup 13}CO J = 1-0 emission and local thermodynamic equilibrium conditions. The mean fractional mass of dust sources to host GMC mass is 0.11{sub −0.06}{sup +0.12}. The high column density subregions comprise 0.07{sub −0.05}{sup +0.13} of the mass of the cloud. Owing to our assumptions, these values are upper limits to the true mass fractions. The fractional mass of dense gas is independent of GMC mass and gas surface density. The low dense gas mass fraction suggests that the formation of dense structures within GMCs is the primary bottleneck for star formation. The distribution of velocity differences between the dense gas and the low density material along the line of sight is also examined. We find a strong, centrally peaked distribution centered on zero velocity displacement. This distribution of velocity differences is modeled with radially converging flows toward the dense gas position that are randomly oriented with respect to the observed line of sight. These models constrain the infall velocities to be 2-4 km s{sup –1} for various flow configurations.

  16. EXTREME GAS FRACTIONS IN CLUMPY, TURBULENT DISK GALAXIES AT z ∼ 0.1

    SciTech Connect

    Fisher, David B.; Glazebrook, Karl; Bassett, Robert; Bolatto, Alberto; Obreschkow, Danail; Cooper, Erin Mentuch; Wisnioski, Emily; Abraham, Roberto G.; Damjanov, Ivana; Green, Andy; McGregor, Peter

    2014-08-01

    In this Letter, we report the discovery of CO fluxes, suggesting very high gas fractions in three disk galaxies seen in the nearby universe (z ∼ 0.1). These galaxies were investigated as part of the DYnamics of Newly Assembled Massive Objects (DYNAMO) survey. High-resolution Hubble Space Telescope imaging of these objects reveals the presence of large star forming clumps in the bodies of the galaxies, while spatially resolved spectroscopy of redshifted Hα reveals the presence of high dispersion rotating disks. The internal dynamical state of these galaxies resembles that of disk systems seen at much higher redshifts (1 < z < 3). Using CO(1-0) observations made with the Plateau de Bure Interferometer, we find gas fractions of 20%-30% and depletion times of t {sub dep} ∼ 0.5 Gyr (assuming a Milky-Way-like α{sub CO}). These properties are unlike those expected for low-redshift galaxies of comparable specific star formation rate, but they are normal for their high-z counterparts. DYNAMO galaxies break the degeneracy between gas fraction and redshift, and we show that the depletion time per specific star formation rate for galaxies is closely tied to gas fraction, independent of redshift. We also show that the gas dynamics of two of our local targets corresponds to those expected from unstable disks, again resembling the dynamics of high-z disks. These results provide evidence that DYNAMO galaxies are local analogs to the clumpy, turbulent disks, which are often found at high redshift.

  17. Angular Momentum Regulates Atomic Gas Fractions of Galactic Disks

    NASA Astrophysics Data System (ADS)

    Obreschkow, D.; Glazebrook, K.; Kilborn, V.; Lutz, K.

    2016-06-01

    We show that the mass fraction {f}{{atm}}=1.35{M}{{H}{{I}}}/M of neutral atomic gas (H i and He) in isolated local disk galaxies of baryonic mass M is well described by a straightforward stability model for flat exponential disks. In the outer disk parts, where gas at the characteristic dispersion of the warm neutral medium is stable in the sense of Toomre, the disk consists of neutral atomic gas; conversely, the inner part where this medium would be Toomre-unstable, is dominated by stars and molecules. Within this model, {f}{{atm}} only depends on a global stability parameter q\\equiv jσ /({GM}), where j is the baryonic specific angular momentum of the disk and σ the velocity dispersion of the atomic gas. The analytically derived first-order solution {f}{{atm}}={min}\\{1,2.5{q}1.12\\} provides a good fit to all plausible rotation curves. This model, with no free parameters, agrees remarkably well (±0.2 dex) with measurements of {f}{{atm}} in isolated local disk galaxies, even with galaxies that are extremely H i-rich or H i-poor for their mass. The finding that {f}{{atm}} increasing monotonically with q for pure stability reasons offers a powerful intuitive explanation for the mean variation of {f}{{atm}} with M: in a cold dark matter universe, galaxies are expected to follow j\\propto {M}2/3, which implies the average scaling q\\propto {M}-1/3 and hence {f}{{atm}}\\propto {M}-0.37, in agreement with the observations.

  18. [High Pressure Gas Tanks

    NASA Technical Reports Server (NTRS)

    Quintana, Rolando

    2002-01-01

    Four high-pressure gas tanks, the basis of this study, were especially made by a private contractor and tested before being delivered to NASA Kennedy Space Center. In order to insure 100% reliability of each individual tank the staff at KSC decided to again submit the four tanks under more rigorous tests. These tests were conducted during a period from April 10 through May 8 at KSC. This application further validates the predictive safety model for accident prevention and system failure in the testing of four high-pressure gas tanks at Kennedy Space Center, called Continuous Hazard Tracking and Failure Prediction Methodology (CHTFPM). It is apparent from the variety of barriers available for a hazard control that some barriers will be more successful than others in providing protection. In order to complete the Barrier Analysis of the system, a Task Analysis and a Biomechanical Study were performed to establish the relationship between the degree of biomechanical non-conformities and the anomalies found within the system on particular joints of the body. This relationship was possible to obtain by conducting a Regression Analysis to the previously generated data. From the information derived the body segment with the lowest percentage of non-conformities was the neck flexion with 46.7%. Intense analysis of the system was conducted including Preliminary Hazard Analysis (PHA), Failure Mode and Effect Analysis (FMEA), and Barrier Analysis. These analyses resulted in the identification of occurrences of conditions, which may be becoming hazardous in the given system. These conditions, known as dendritics, may become hazards and could result in an accident, system malfunction, or unacceptable risk conditions. A total of 56 possible dendritics were identified. Work sampling was performed to observe the occurrence each dendritic. The out of control points generated from a Weighted c control chart along with a Pareto analysis indicate that the dendritics "Personnel not

  19. Properties of molecular gas in galaxies in the early and mid stages of interaction. II. Molecular gas fraction

    NASA Astrophysics Data System (ADS)

    Kaneko, Hiroyuki; Kuno, Nario; Iono, Daisuke; Tamura, Yoichi; Tosaki, Tomoka; Nakanishi, Kouichiro; Sawada, Tsuyoshi

    2017-08-01

    We have investigated properties of the interstellar medium in interacting galaxies in early and mid stages using mapping data of 12CO(J = 1-0) and H i. Assuming the standard CO-H2 conversion factor, we found no difference in molecular gas mass, atomic gas mass, and total gas mass (the sum of atomic and molecular gas mass) between interacting galaxies and isolated galaxies. However, interacting galaxies have a higher global molecular gas fraction f_{mol}^{global} (the ratio of molecular gas mass to total gas mass averaged over a whole galaxy) at 0.71 ± 0.15 than isolated galaxies (0.52 ± 0.18). The distribution of the local molecular gas fraction fmol, the ratio of the surface density of molecular gas to that of the total gas, is different from the distribution in typical isolated galaxies. By a pixel-to-pixel comparison, isolated spiral galaxies show a gradual increase in fmol along the surface density of total gas until it is saturated at 1.0, while interacting galaxies show no clear relation. We performed pixel-to-pixel theoretical model fits by varying metallicity and external pressure. According to the model fitting, external pressure can explain the trend of fmol in the interacting galaxies. Assuming half of the standard CO-H2 conversion factor for interacting galaxies, the results of pixel-to-pixel theoretical model fitting get worse than adopting the standard conversion factor, although f_{mol}^{global} of interacting galaxies (0.62 ± 0.17) becomes the same as in isolated galaxies. We conclude that external pressure occurs due to the shock prevailing over a whole galaxy or due to collisions between giant molecular clouds even in the early stage of the interaction. The external pressure accelerates an efficient transition from atomic gas to molecular gas. Regarding the chemical timescale, high fmol can be achieved at the very early stage of interaction even if the shock induced by the collision of galaxies ionizes interstellar gas.

  20. The Gas-Phase Deuterium Fractionation of Formaldehyde

    NASA Astrophysics Data System (ADS)

    Osamura, Yoshihiro; Roberts, Helen; Herbst, Eric

    2005-03-01

    The dominant mechanism for the deuteration of formaldehyde in the gas phase of low-temperature interstellar cloud cores occurs via reaction with the deuterating ions H2D+, HD+2, and D+3. Until now, it has been assumed that deuteration leads to an ion that, on recombination with electrons, can produce a deuterated neutral species with a statistical branching fraction. Quantum chemical calculations reported here, however, show an entirely different picture, in which the deuteration of formaldehyde leads to the molecular ion H2COD+, where the deuterium binds only on the oxygen side of the molecule. The structure is quite stable, while an alternative structure, H2DCO+, cannot be produced in a straightforward manner. Dissociative recombination of H2COD+ to reproduce a formaldehyde structure then removes the deuteration if the dissociation is direct, i.e., it occurs without change of structure. There are several possible indirect mechanisms by which dissociative recombination can lead to HDCO, however. For example, if the direct products are HCOD+H, it is possible that subsequent isomerization to HDCO can occur, although this involved process is unlikely. Another possibility is isomerization during the actual dissociation of the H2COD intermediate. Models of deuterium fractionation in which dissociative recombination is predominantly direct are presented, and it is found that the deuterium fractionation of formaldehyde to form both HDCO and D2CO can still occur via other mechanisms, although with less efficiency than previously obtained. If the dissociative recombination is half indirect, however, then we can recover the previously calculated efficiency.

  1. Galaxy evolution in cosmological simulations with outflows - II. Metallicities and gas fractions

    NASA Astrophysics Data System (ADS)

    Davé, Romeel; Finlator, Kristian; Oppenheimer, Benjamin D.

    2011-09-01

    We use cosmological hydrodynamic simulations to investigate how inflows, star formation and outflows govern the gaseous and metal content of galaxies within a hierarchical structure formation context. In our simulations, galaxy metallicities are established by a balance between inflows and outflows as governed by the mass outflow rate, implying that the mass-metallicity relation reflects how the outflow rate varies with stellar mass. Gas content, meanwhile, is set by a competition between inflow into and gas consumption within the interstellar medium, the latter being governed by the star formation law, while the former is impacted by both wind recycling and preventive feedback. Stochastic variations in the inflow rate move galaxies off the equilibrium mass-metallicity and mass-gas fraction relations in a manner correlated with the star formation rate, and the scatter is set by the time-scale to re-equilibrate. The evolution of both relations from z= 3 → 0 is slow, as individual galaxies tend to evolve mostly along the relations. Gas fractions at a given stellar mass slowly decrease with time because the cosmic inflow rate diminishes faster than the consumption rate, while metallicities slowly increase as infalling gas becomes more enriched. Observations from z˜ 3 → 0 are better matched by simulations employing momentum-driven wind scalings rather than constant wind speeds, but all models predict too low gas fractions at low masses and too high metallicities at high masses. All our models reproduce observed second-parameter trends of the mass-metallicity relation with the star formation rate and environment, indicating that these are a consequence of equilibrium and not feedback. Overall, the analytical framework of our equilibrium scenario broadly captures the relevant physics establishing the galaxy gas and metal content in simulations, which suggests that the cycle of baryonic inflows and outflows centrally governs the cosmic evolution of these properties

  2. Salinity independent measurement of gas volume fraction in oil/gas/water pipe flows

    PubMed

    Johansen; Jackson

    2000-10-01

    Dual mode densitometry is presented as a novel method of measuring the gas volume fraction in gas/oil/water pipe flows independent of the salinity of the water component. The different response in photoelectric attenuation and Compton scattering to changes in salinity is utilized. The total attenuation coefficient is found through traditional transmission measurements with a detector positioned outside the pipe wall diametrically opposite the source. The scatter response is measured with a second detector positioned somewhere between the source and the transmission detector. The feasibility of the method is demonstrated for homogeneously mixed flows.

  3. The dense gas mass fraction in the W51 cloud and its protoclusters

    NASA Astrophysics Data System (ADS)

    Ginsburg, Adam; Bally, John; Battersby, Cara; Youngblood, Allison; Darling, Jeremy; Rosolowsky, Erik; Arce, Héctor; Lebrón Santos, Mayra E.

    2015-01-01

    Context. The density structure of molecular clouds determines how they will evolve. Aims: We map the velocity-resolved density structure of the most vigorously star-forming molecular cloud in the Galactic disk, the W51 giant molecular cloud. Methods: We present new 2 cm and 6 cm maps of H2CO, radio recombination lines, and the radio continuum in the W51 star forming complex acquired with Arecibo and the Green Bank Telescope at ~ 50″ resolution. We use H2CO absorption to determine the relative line-of-sight positions of molecular and ionized gas. We measure gas densities using the H2CO densitometer, including continuous measurements of the dense gas mass fraction (DGMF) over the range 104cm-3gas mass fraction has been measured over a range of densities with a single data set. Results: The DGMF in W51 A is high, f ≳ 70% above n> 104cm-3, while it is low, f< 20%, in W51 B. We did not detect any H2CO emission throughout the W51 GMC; all gas dense enough to emit under normal conditions is in front of bright continuum sources and therefore is seen in absorption instead. Conclusions: (1) The dense gas fraction in the W51 A and B clouds shows that W51 A will continue to form stars vigorously, while star formation has mostly ended in W51 B. The lack of dense, star-forming gas around W51 C indicates that collect-and-collapse is not acting or is inefficient in W51. (2) Ongoing high-mass star formation is correlated with n ≳ 1 × 105cm-3 gas. Gas with n> 104cm-3 is weakly correlated with low and moderate mass star formation, but does not strongly correlate with high-mass star formation. (3) The nondetection of H2CO emission implies that the emission detected in other galaxies, e.g. Arp 220, comes from high-density gas that is not directly affiliated with already-formed massive stars. Either the non-star-forming ISM of these galaxies is very dense, implying the star formation density threshold is higher, or H ii regions

  4. High pressure synthesis gas fermentation

    SciTech Connect

    Not Available

    1991-01-01

    Construction of the high pressure gas phase fermentation system is nearing completion. All non-explosion proof components will be housed separately in a gas-monitored plexiglas cabinet. A gas-monitoring system has been designed to ensure the safety of the operations in case of small or large accidental gas releases. Preliminary experiments investigating the effects of high pressure on Clostridium 1jungdahlii have shown that growth and CO uptake are not negatively affected and CO uptake by an increased total pressure of 100 psig at a syngas partial pressure of 10 psig.

  5. Mass fractionation of noble gases in synthetic methane hydrate: Implications for naturally occurring gas hydrate dissociation

    USGS Publications Warehouse

    Hunt, Andrew G.; Stern, Laura; Pohlman, John W.; Ruppel, Carolyn; Moscati, Richard J.; Landis, Gary P.

    2013-01-01

    As a consequence of contemporary or longer term (since 15 ka) climate warming, gas hydrates in some settings may presently be dissociating and releasing methane and other gases to the ocean-atmosphere system. A key challenge in assessing the impact of dissociating gas hydrates on global atmospheric methane is the lack of a technique able to distinguish between methane recently released from gas hydrates and methane emitted from leaky thermogenic reservoirs, shallow sediments (some newly thawed), coal beds, and other sources. Carbon and deuterium stable isotopic fractionation during methane formation provides a first-order constraint on the processes (microbial or thermogenic) of methane generation. However, because gas hydrate formation and dissociation do not cause significant isotopic fractionation, a stable isotope-based hydrate-source determination is not possible. Here, we investigate patterns of mass-dependent noble gas fractionation within the gas hydrate lattice to fingerprint methane released from gas hydrates. Starting with synthetic gas hydrate formed under laboratory conditions, we document complex noble gas fractionation patterns in the gases liberated during dissociation and explore the effects of aging and storage (e.g., in liquid nitrogen), as well as sampling and preservation procedures. The laboratory results confirm a unique noble gas fractionation pattern for gas hydrates, one that shows promise in evaluating modern natural gas seeps for a signature associated with gas hydrate dissociation.

  6. Stable Vanadium Isotope Fractionation at High Temperatures

    NASA Astrophysics Data System (ADS)

    Prytulak, J.; Parkinson, I. J.; Savage, P. S.; Nielsen, S. G.; Halliday, A. N.

    2011-12-01

    Vanadium is a redox sensitive transition metal existing in multiple valence states at terrestrial conditions. Stable vanadium isotopes (reported as δ51V in % relative to an Alfa Aesar standard [1]) are a potentially powerful tracer of oxidation-reduction processes. However, the determination of δ51V is analytically challenging, primarily due to the extreme abundance ratio between the only two stable isotopes (51V/50V ~ 400) and, also, significant isobaric interferences of 50Ti and 50Cr on the minor 50V isotope. We have developed the first method able to determine δ51V to a precision (2 s.d. ~ 0.15%, [1,2]) that enables application of this isotope system to geological processes. To usefully investigate high temperature processes using vanadium isotopes, knowledge of the isotope composition and range of values present in the ambient mantle is required. Here we discuss the first δ51V measured in igneous materials encompassing peridotites, MORB, and primitive mantle-derived melts such as picrites. This first dataset provides a preliminary reconnaissance of the magnitude of natural fractionation. We find little isotope fractionation in suites of peridotites and MORB (< 0.5 %). However, the small but analytically significant variation appears to be related to secondary processes, with extremely altered peridotites consistently displaying slightly heavier isotope compositions. We find no resolvable δ51V variation between fresh MORB glass and fresh peridotite. Intriguingly, a suite of subduction-related peridotites from the Mariana forearc, previously characterized for fO2 [3], do not display the predicted co-variation between δ51V and fO2, but instead also have compositions identical to MORB glass. This nominally supports recent indications that there is limited difference in the oxygen fugacity of the MORB source and the subarc mantle wedge [e.g., 4, 5]. Finally, we observe large δ51V variations (~ 2 %) in a suite of evolving lavas from Hekla volcano, Iceland

  7. Experimental studies and model analysis of noble gas fractionation in porous media

    USGS Publications Warehouse

    Ding, Xin; Kennedy, B. Mack.; Evans, William C.; Stonestrom, David A.

    2016-01-01

    The noble gases, which are chemically inert under normal terrestrial conditions but vary systematically across a wide range of atomic mass and diffusivity, offer a multicomponent approach to investigating gas dynamics in unsaturated soil horizons, including transfer of gas between saturated zones, unsaturated zones, and the atmosphere. To evaluate the degree to which fractionation of noble gases in the presence of an advective–diffusive flux agrees with existing theory, a simple laboratory sand column experiment was conducted. Pure CO2 was injected at the base of the column, providing a series of constant CO2 fluxes through the column. At five fixed sampling depths within the system, samples were collected for CO2 and noble gas analyses, and ambient pressures were measured. Both the advection–diffusion and dusty gas models were used to simulate the behavior of CO2 and noble gases under the experimental conditions, and the simulations were compared with the measured depth-dependent concentration profiles of the gases. Given the relatively high permeability of the sand column (5 ´ 10−11 m2), Knudsen diffusion terms were small, and both the dusty gas model and the advection–diffusion model accurately predicted the concentration profiles of the CO2 and atmospheric noble gases across a range of CO2 flux from ?700 to 10,000 g m−2 d−1. The agreement between predicted and measured gas concentrations demonstrated that, when applied to natural systems, the multi-component capability provided by the noble gases can be exploited to constrain component and total gas fluxes of non-conserved (CO2) and conserved (noble gas) species or attributes of the soil column relevant to gas transport, such as porosity, tortuosity, and gas saturation.

  8. Steady state fractionation of heavy noble gas isotopes in a deep unsaturated zone

    USGS Publications Warehouse

    Seltzer, Alan M.; Severinghaus, Jeffrey P.; Andraski, Brian; Stonestrom, David A.

    2017-01-01

    To explore steady state fractionation processes in the unsaturated zone (UZ), we measured argon, krypton, and xenon isotope ratios throughout a ∼110 m deep UZ at the United States Geological Survey (USGS) Amargosa Desert Research Site (ADRS) in Nevada, USA. Prior work has suggested that gravitational settling should create a nearly linear increase in heavy-to-light isotope ratios toward the bottom of stagnant air columns in porous media. Our high-precision measurements revealed a binary mixture between (1) expected steady state isotopic compositions and (2) unfractionated atmospheric air. We hypothesize that the presence of an unsealed pipe connecting the surface to the water table allowed for direct inflow of surface air in response to extensive UZ gas sampling prior to our first (2015) measurements. Observed isotopic resettling in deep UZ samples collected a year later, after sealing the pipe, supports this interpretation. Data and modeling each suggest that the strong influence of gravitational settling and weaker influences of thermal diffusion and fluxes of CO2 and water vapor accurately describe steady state isotopic fractionation of argon, krypton, and xenon within the UZ. The data confirm that heavy noble gas isotopes are sensitive indicators of UZ depth. Based on this finding, we outline a potential inverse approach to quantify past water table depths from noble gas isotope measurements in paleogroundwater, after accounting for fractionation during dissolution of UZ air and bubbles.

  9. Steady state fractionation of heavy noble gas isotopes in a deep unsaturated zone

    NASA Astrophysics Data System (ADS)

    Seltzer, Alan M.; Severinghaus, Jeffrey P.; Andraski, Brian J.; Stonestrom, David A.

    2017-04-01

    To explore steady state fractionation processes in the unsaturated zone (UZ), we measured argon, krypton, and xenon isotope ratios throughout a ˜110 m deep UZ at the United States Geological Survey (USGS) Amargosa Desert Research Site (ADRS) in Nevada, USA. Prior work has suggested that gravitational settling should create a nearly linear increase in heavy-to-light isotope ratios toward the bottom of stagnant air columns in porous media. Our high-precision measurements revealed a binary mixture between (1) expected steady state isotopic compositions and (2) unfractionated atmospheric air. We hypothesize that the presence of an unsealed pipe connecting the surface to the water table allowed for direct inflow of surface air in response to extensive UZ gas sampling prior to our first (2015) measurements. Observed isotopic resettling in deep UZ samples collected a year later, after sealing the pipe, supports this interpretation. Data and modeling each suggest that the strong influence of gravitational settling and weaker influences of thermal diffusion and fluxes of CO2 and water vapor accurately describe steady state isotopic fractionation of argon, krypton, and xenon within the UZ. The data confirm that heavy noble gas isotopes are sensitive indicators of UZ depth. Based on this finding, we outline a potential inverse approach to quantify past water table depths from noble gas isotope measurements in paleogroundwater, after accounting for fractionation during dissolution of UZ air and bubbles.

  10. Ensiling effects of the ethanol fractionation of forages using gas production.

    PubMed

    Doane, P H; Pell, A N; Schofield, P

    1998-03-01

    We studied the use of gas curve subtraction to distinguish between two fractions soluble in neutral detergent solution. Samples of unfractionated (whole) forage, residue insoluble in 90% ethanol, and isolated NDF were fermented in vitro, and gas production was monitored. The gas volume associated with the ethanol solubles (A fraction) was determined as the difference between the gas from the whole forage and from the ethanol residue. The gas yield associated with the fraction insoluble in 90% ethanol but soluble in neutral detergent solution (B fraction) was determined by subtracting the isolated NDF gas curve from the corresponding ethanol residue curve. This experiment included three forages (alfalfa, bromegrass, and orchardgrass) harvested at two maturities and preserved by freeze-drying or ensiling to form a 3 x 2 x 2 factorial arrangement. Ensiling reduced the rate of gas formation from the A fraction by approximately 30% (P < .01). Ensiling increased (P < .05) the size of the A fraction (2 to 10% of DM) but did not change the volume of gas produced (P > .05). The gas yield from the B1 fraction was reduced 40% (P < .05) by ensiling with no significant change in rate. Curve subtraction of gas production profiles may be used to obtain rate estimates for multiple neutral detergent soluble pools. The separation of the neutral detergent solubles into two pools clarified the effects caused by ensiling. Changes due to ensiling on the rate of gas produced were associated with the A fraction, and the effects on final gas volume were associated with the B1 fraction.

  11. High gas flow alpha detector

    DOEpatents

    Bolton, R.D.; Bounds, J.A.; Rawool-Sullivan, M.W.

    1996-05-07

    An alpha detector for application in areas of high velocity gas flows, such as smokestacks and air vents. A plurality of spaced apart signal collectors are placed inside an enclosure, which would include smokestacks and air vents, in sufficient numbers to substantially span said enclosure so that gas ions generated within the gas flow are electrostatically captured by the signal collector means. Electrometer means and a voltage source are connected to the signal collectors to generate an electrical field between adjacent signal collectors, and to indicate a current produced through collection of the gas ions by the signal collectors. 4 figs.

  12. High gas flow alpha detector

    DOEpatents

    Bolton, Richard D.; Bounds, John A.; Rawool-Sullivan, Mohini W.

    1996-01-01

    An alpha detector for application in areas of high velocity gas flows, such as smokestacks and air vents. A plurality of spaced apart signal collectors are placed inside an enclosure, which would include smokestacks and air vents, in sufficient numbers to substantially span said enclosure so that gas ions generated within the gas flow are electrostatically captured by the signal collector means. Electrometer means and a voltage source are connected to the signal collectors to generate an electrical field between adjacent signal collectors, and to indicate a current produced through collection of the gas ions by the signal collectors.

  13. Development of a fraction collector for coupling gas chromatography with an AMS facility

    NASA Astrophysics Data System (ADS)

    Rottenbach, Andreas; Uhl, T.; Hain, A.; Scharf, A.; Kritzler, K.; Kretschmer, W.

    2008-05-01

    It has been shown that microscale 14C measurements are possible by using a gas handling system and a gas ion source [T. Uhl, W. Kretschmer, W. Luppold, A. Scharf, AMS measurements from microgram to milligram, Nucl. Instr. and Meth. (2005) 474 (240th ed.), T. Uhl, W. Luppold, A. Rottenbach, A. Scharf, K. Kritzler, W. Kretschmer, Development of an automatic gas handling system for microscale AMS (14C) measurements, Nucl. Instr. and Meth. (2007) 303 (259th ed.)]. In Erlangen a gas handling system was especially developed for environmental and biomedical investigations. For the separation of the compound of interest a standard gas chromatograph (GC) is used. To minimize the sample contamination and sample loss we have designed a fraction collector that connects a GC and an elemental analyzer (EA) directly. The selected compound is combusted in the EA and the resulting CO2 is then transferred into the gas handling system for AMS measurements. From the beginning of GC preparation up to the AMS measurement the sample is in a closed line. All operations are fully automated, so no manual operations are necessary. This guarantees high cleanness and maximum sample yield. Preliminary measurements are done using modern and old ethyl alcohol (from fermentation and of petrochemical origin, respectively). The results are consistent with their expected values although cross contamination and background signal increased as the sample mass was decreased.

  14. High pressure synthesis gas fermentation

    SciTech Connect

    Not Available

    1992-01-01

    The construction of the high pressure gas phase fermentation system has been completed. Photographs of the various components of the system are presented, along with an operating procedure for the equipment.

  15. In Situ Void Fraction and Gas Volume in Hanford Tank 241-SY-101 as Measured with the Void Fraction Instrument

    SciTech Connect

    CW Stewart; G Chen; JM Alzheimer; PA Meyer

    1998-11-10

    The void fraction instrument (WI) was deployed in Tank 241-SY-101 three times in 1998 to confm and locate the retained gas (void) postulated to be causing the accelerating waste level rise observed since 1995. The design, operation, and data reduction model of the WI are described along with validation testing and potential sources of uncertainty. The test plans, field observations and void measurements are described in detail, including the total gas volume calculations and the gas volume model. Based on 1998 data, the void fraction averaged 0.013 i 0.001 in the mixed slurry and 0.30 ~ 0.04 in the crust. This gives gas volumes (at standard pressure and temperature) of 87 t 9 scm in the slurry and 138 ~ 22 scm in the crust for a total retained gas volume of221 *25 scm. This represents an increase of about 74 scm in the crust and a decrease of about 34 scm in the slurry from 1994/95 results. The overall conclusion is that the gas retention is occurring mainly in the crust layer and there is very little gas in the mixed slurry and loosely settled layers below. New insights on crust behavior are also revealed.

  16. Scalable fractionation of iron oxide nanoparticles using a CO2 gas-expanded liquid system

    NASA Astrophysics Data System (ADS)

    Vengsarkar, Pranav S.; Xu, Rui; Roberts, Christopher B.

    2015-10-01

    Iron oxide nanoparticles exhibit highly size-dependent physicochemical properties that are important in applications such as catalysis and environmental remediation. In order for these size-dependent properties to be effectively harnessed for industrial applications scalable and cost-effective techniques for size-controlled synthesis or size separation must be developed. The synthesis of monodisperse iron oxide nanoparticles can be a prohibitively expensive process on a large scale. An alternative involves the use of inexpensive synthesis procedures followed by a size-selective processing technique. While there are many techniques available to fractionate nanoparticles, many of the techniques are unable to efficiently fractionate iron oxide nanoparticles in a scalable and inexpensive manner. A scalable apparatus capable of fractionating large quantities of iron oxide nanoparticles into distinct fractions of different sizes and size distributions has been developed. Polydisperse iron oxide nanoparticles (2-20 nm) coated with oleic acid used in this study were synthesized using a simple and inexpensive version of the popular coprecipitation technique. This apparatus uses hexane as a CO2 gas-expanded liquid to controllably precipitate nanoparticles inside a 1L high-pressure reactor. This paper demonstrates the operation of this new apparatus and for the first time shows the successful fractionation results on a system of metal oxide nanoparticles, with initial nanoparticle concentrations in the gram-scale. The analysis of the obtained fractions was performed using transmission electron microscopy and dynamic light scattering. The use of this simple apparatus provides a pathway to separate large quantities of iron oxide nanoparticles based upon their size for use in various industrial applications.

  17. [Mutagenicity of 3 organic fractions of atmospheric dust and gas chromatographic analysis of the basic fraction].

    PubMed

    Gottlieb, A; Schleibinger, H; Ketseridis, G; Wullenweber, M; Rüden, H

    1983-01-01

    Suspended particulate matter (PM) with a Dae less than 0.4 micron was collected from July 1981 till January 1982. The ether/benzene soluble extract (EEOM) and the acidic, basic and neutral fractions were determined and investigated for their mutagenic activities in the Ames bioassay. In addition particles (Dae) less than 10.2 micron derived in January were investigated. Five compounds of the basic fraction were determined by gaschromatography. The following results were obtained: Suspended particulate matter (Dae less than 0.4 micron) and the ether/benzene extract increase from July to January. The lowest rates occur in July (PM: 16.9 micron/m3) and August (EEOM: 3.0 micrograms/m3), the highest in January (PM: 48.9 micrograms/m3, EEOM: 10.5 micrograms/m3). The ether/benzene soluble portion of the suspended particulate matter increases from the average rate of 16.3% (July-September) to 22.7% (November-January). The neutral fraction amounts to 44.9%, the acidic fraction to 27.3% and the basic fraction to 3.5% of the organic matter (on an average). In experiments with metabolic activation 99% of the total mutagenicity during the period of July till September can be demonstrated by summing up the mutagenicity of the three fractions on the other hand only 59.7% from November till January. The EEOMs derived from winter exhibit without metabolic activation (250 micrograms/plate) distinctively higher numbers of revertants than the single fractions. Dose-response curves of extracts derived from back-up filters (Dae less than 0.4 micron) in January show that the acidic fraction has a slightly higher mutagenic activity than the neutral fraction (mean values of tests with and without S9-mix). The basic fraction shows no mutagenicity without S9-mix, with activation the mutagenic activity is lower than that of the other fractions. Mutagenicity expressed as rev./m3 air shows, that the neutral fraction is most efficient. The number of revertants per plate reveals-in relation to

  18. XMM-NEWTON observation of Abell 1835: Temperature, mass and gas mass fraction profiles

    NASA Astrophysics Data System (ADS)

    Majerowicz, S.; Neumann, D. M.; Reiprich, T. H.

    2002-10-01

    We present a study of the medium distant cluster of galaxies Abell 1835 based on XMM-NEWTON data. The high quality of XMM-NEWTON data enable us to perform spectro-imaging of the cluster up to large radii. We determine the gas and total mass profiles based on the hydrostatic approach using the beta-model and the temperature profile. For the determination of the temperature profile of the ICM, which is needed for the mass determination, we apply a double background subtraction, which accounts for the various kinds of background present (particle and astrophysical background). We find a basically flat temperature profile up to 0.75 r200 with a temperature decrease towards the center linked to the cooling flow. We obtain a gas mass fraction of (20.7+/-3.7)%, which is a lower limit on the baryon fraction in this cluster. Using this value as baryon fraction for the entire Universe, we obtain by combining our results with results based on primordial nucleosynthesis, an upper limit for Omegam <0.5h50-1/2, which is in good agreement with other recent studies.

  19. High power gas laser amplifier

    DOEpatents

    Leland, Wallace T.; Stratton, Thomas F.

    1981-01-01

    A high power output CO.sub.2 gas laser amplifier having a number of sections, each comprising a plurality of annular pumping chambers spaced around the circumference of a vacuum chamber containing a cold cathode, gridded electron gun. The electron beam from the electron gun ionizes the gas lasing medium in the sections. An input laser beam is split into a plurality of annular beams, each passing through the sections comprising one pumping chamber.

  20. High efficiency gas burner

    DOEpatents

    Schuetz, Mark A.

    1983-01-01

    A burner assembly provides for 100% premixing of fuel and air by drawing the air into at least one high velocity stream of fuel without power assist. Specifically, the nozzle assembly for injecting the fuel into a throat comprises a plurality of nozzles in a generally circular array. Preferably, swirl is imparted to the air/fuel mixture by angling the nozzles. The diffuser comprises a conical primary diffuser followed by a cusp diffuser.

  1. Cavity Enhanced Spectrometer performance assessment for greenhouse gas dry mole fraction measurement in humid air.

    NASA Astrophysics Data System (ADS)

    Laurent, Olivier; Yver Kwok, Camille; Guemri, Ali; Philippon, Carole; Rivier, Leonard; Ramonet, Michel

    2017-04-01

    Due to the high variability of the water vapor content in the atmosphere, the mole fraction of trace gas such as greenhouse gas (GHG) in the atmosphere is usually presented as mole fraction in dry air. In consequence, the first technology used for GHG measurement, gas chromatography or non-dispersive infra-red spectroscopy, required to dry the air sample prior to analysis at a dew point lower than -50°C. The emergence of new GHG analyzers using infrared Enhanced Cavity Spectroscopy which measure the water vapor content in the air sample, allows providing the dry mole fraction of GHG without any drying system upstream by applying appropriate correction of the water vapor effects (dilution, pressure broadening…). In the framework of ICOS, a European research infrastructure aiming to provide harmonized high precision data for advanced research on carbon cycle and GHG budgets over Europe, the Metrology Lab of the Atmosphere Thematic Centre (ATC), located at LSCE in France, is mainly dedicated to elaborating measurement protocols and evaluating performance of GHG analyzers. Among the different tests conducted to characterize the metrological performance, the Metrology Lab focuses on the water vapor correction to apply on the GHG measurement. Most of the analyzers tested at the Metrology Lab are based on Cavity Enhanced Spectroscopy measuring the ICOS mandatory species, CO2, CH4 and CO. This presentation presents the results of the performance assessment of the manufacturer built-in water vapor correction and the possible improvement. Thanks to the large number of instrument tested, the presentation provides a performance overview of the GHG analyzers deployed in the ICOS atmospheric station network. Finally the performance of the water vapor correction will be discussed in regard of the performance obtained by using a drying system.

  2. Orbital Structure of Merger Remnants. I. Effect of Gas Fraction in Pure Disk Mergers

    NASA Astrophysics Data System (ADS)

    Hoffman, Loren; Cox, Thomas J.; Dutta, Suvendra; Hernquist, Lars

    2010-11-01

    Since the violent relaxation in hierarchical merging is incomplete, elliptical galaxies retain a wealth of information about their formation pathways in their present-day orbital structure. Recent advances in integral field spectroscopy, multi-slit infrared spectroscopy, and triaxial dynamical modeling techniques have greatly improved our ability to harvest this information. A variety of observational and theoretical evidence indicates that gas-rich major mergers play an important role in the formation of elliptical galaxies. We simulate 1:1 disk mergers at seven different initial gas fractions (f gas) ranging from 0% to 40%, using a version of the TreeSPH code Gadget-2 that includes radiative heating and cooling, star formation, and feedback from supernovae and active galactic nuclei. We classify the stellar orbits in each remnant and construct radial profiles of the orbital content, intrinsic shape, and orientation. The dissipationless remnants are typically prolate-triaxial, dominated by box orbits within rc ~ 1.5 Re , and by tube orbits in their outer parts. As f gas increases, the box orbits within rc are increasingly replaced by a population of short-axis tubes (z-tubes) with near zero net rotation, and the remnants become progressively more oblate and round. The long-axis tube (x-tube) orbits are highly streaming and relatively insensitive to f gas, implying that their angular momentum is retained from the dynamically cold initial conditions. Outside rc , the orbital structure is essentially unchanged by the gas. For f gas >~ 15%, gas that retains its angular momentum during the merger re-forms a disk that appears in the remnants as a highly streaming z-tube population superimposed on the hot z-tube distribution formed by the old stars. In the 15%-20% gas remnants, this population appears as a kinematically distinct core (KDC) within a system that is slowly rotating or dominated by minor-axis rotation. These remnants show an interesting resemblance, in both

  3. High ratio recirculating gas compressor

    DOEpatents

    Weinbrecht, John F.

    1989-01-01

    A high ratio positive displacement recirculating rotary compressor is disclosed. The compressor includes an integral heat exchanger and recirculation conduits for returning cooled, high pressure discharge gas to the compressor housing to reducing heating of the compressor and enable higher pressure ratios to be sustained. The compressor features a recirculation system which results in continuous and uninterrupted flow of recirculation gas to the compressor with no direct leakage to either the discharge port or the intake port of the compressor, resulting in a capability of higher sustained pressure ratios without overheating of the compressor.

  4. High ratio recirculating gas compressor

    DOEpatents

    Weinbrecht, J.F.

    1989-08-22

    A high ratio positive displacement recirculating rotary compressor is disclosed. The compressor includes an integral heat exchanger and recirculation conduits for returning cooled, high pressure discharge gas to the compressor housing to reducing heating of the compressor and enable higher pressure ratios to be sustained. The compressor features a recirculation system which results in continuous and uninterrupted flow of recirculation gas to the compressor with no direct leakage to either the discharge port or the intake port of the compressor, resulting in a capability of higher sustained pressure ratios without overheating of the compressor. 10 figs.

  5. Iron Isotope Fractionation at High Temperatures

    NASA Astrophysics Data System (ADS)

    Weyer, S.; Arnold, G.; Chakrabarti, R.; Anbar, A.

    2003-04-01

    Most observed Fe isotope variations are believed to result from low temperature processes, (e.g., Beard et al., 1999; Anbar et al., 2000; Zhu et al., 2000). At high temperatures, the magnitude of equilibrium fractionation factors decreases. Beard et al. (2003) observed no variation between igneous rocks beyond their precision of ± 0.1 ppm (2SD), respectively. In contrast, Zhu et al. (2002), Poitrasson et al. (2002) and Williams et al. (2002) reported Fe isotope variations in the sub-per mil level between various mineral phases in the mantle or different igneous rocks from the Earth and other planetary bodies. The work of Zhu et al. (2002), Poitrasson et al. (2002) and Williams et al. (2002) employed the use of desolvation nebulization to minimize ArO^+, ArOH+ and ArN^+ interferences, and sample-standard bracketing assuming identical instrument mass bias between samples and standards. We are assessing this question using a high mass resolution MC-ICPMS with the technique of Weyer et al., submitted. With this technique molecular interferences are adequately resolved. Samples can be measured with both wet or dry plasma conditions to assess potential matrix effects. Increased precision for rock samples is achieved using Cu for mass bias correction. An external precision of 0.1 ppm (2SD) can be achieved for δ56Fe. In preliminary measurements of Fe from mineral separates from different terrestrial igneous rocks, mesosiderites and pallasites all samples fall within a range of ± 0.2 ppm, with slightly positive (0.1-0.2 ppm) δ56Fe compared to IRMM014 in average. Further results and interpretations will be presented. References: Anbar, A.D., et al., (2000) Science 288, 126. Beard, B.L., et al. (1999) Science 285, 1889. Beard, B.L. et al. (2003) Chem. Geol. , special issue, in press. Poitrasson, F., et al., (2002) Geochim. Cosmochim. Acta Suppl. 66, A608. Weyer, S. and Schwieters, J. B. (2002) submitted to Int. J. Mass Spectr. Williams, H., et al., (2002) Geochim

  6. Enhanced Lipidome Coverage in Shotgun Analyses by using Gas-Phase Fractionation

    NASA Astrophysics Data System (ADS)

    Nazari, Milad; Muddiman, David C.

    2016-11-01

    A high resolving power shotgun lipidomics strategy using gas-phase fractionation and data-dependent acquisition (DDA) was applied toward comprehensive characterization of lipids in a hen ovarian tissue in an untargeted fashion. Using this approach, a total of 822 unique lipids across a diverse range of lipid categories and classes were identified based on their MS/MS fragmentation patterns. Classes of glycerophospholipids and glycerolipids, such as glycerophosphocholines (PC), glycerophosphoethanolamines (PE), and triglycerides (TG), are often the most abundant peaks observed in shotgun lipidomics analyses. These ions suppress the signal from low abundance ions and hinder the chances of characterizing low abundant lipids when DDA is used. These issues were circumvented by utilizing gas-phase fractionation, where DDA was performed on narrow m/z ranges instead of a broad m/z range. Employing gas-phase fractionation resulted in an increase in sensitivity by more than an order of magnitude in both positive- and negative-ion modes. Furthermore, the enhanced sensitivity increased the number of lipids identified by a factor of ≈4, and facilitated identification of low abundant lipids from classes such as cardiolipins that are often difficult to observe in untargeted shotgun analyses and require sample-specific preparation steps prior to analysis. This method serves as a resource for comprehensive profiling of lipids from many different categories and classes in an untargeted manner, as well as for targeted and quantitative analyses of individual lipids. Furthermore, this comprehensive analysis of the lipidome can serve as a species- and tissue-specific database for confident identification of other MS-based datasets, such as mass spectrometry imaging.

  7. A high-speed algorithm for computation of fractional differentiation and fractional integration.

    PubMed

    Fukunaga, Masataka; Shimizu, Nobuyuki

    2013-05-13

    A high-speed algorithm for computing fractional differentiations and fractional integrations in fractional differential equations is proposed. In this algorithm, the stored data are not the function to be differentiated or integrated but the weighted integrals of the function. The intervals of integration for the memory can be increased without loss of accuracy as the computing time-step n increases. The computing cost varies as n log n, as opposed to n(2) of standard algorithms.

  8. The Relationships of Wood-, Gas- and Water Fractions of Tree Stems to Performance and Life History Variation in Tropical Trees

    PubMed Central

    Poorter, Lourens

    2008-01-01

    Background and Aims The volume of tree stems is made up of three components: solid wood, gas and water. These components have important consequences for the construction costs, strength and stability of trees. Here, the importance of stem components for sapling growth and survival in the field was investigated, and then these stem components were related to two important life history axes of variation: the light requirements for regeneration and the adult stature of the species. Methods Stem fractions of wood, gas and water were determined for saplings and adults of respectively 30 and 58 Bolivian tropical moist-forest species. Sapling height growth and survival were monitored for 2 years in the field as indicators of sapling performance. Key Results Sapling stems consisted of 26 % wood (range 7–36 % for species), 59 % water (range 49–88 %), and 15 % gas (range 0–38 %) per unit volume. The wood fraction was the only determinant of sapling performance and was correlated with increased survival and decreased growth rate across species. The wood fraction decreased with light requirements of the species, probably because a high wood fraction protects shade-tolerant species against pathogens and falling debris. The gas fraction increased with the light requirements and adult stature of the species; probably as an aid in realizing a rapid height growth and accessing the canopy in the case of light-demanding species, and for rapidly attaining stability and a large reproductive size in the case of tall species. The water fraction was not correlated with the life history variation of tree species, probably because it leads to increased stem loading and decreased stability. Conclusions The wood fraction might partially explain the growth–survival trade-off that has been found across tropical tree species. The wood and gas fractions are closely related to the regeneration light requirements of the species. Tall species have a high gas fraction, probably not only

  9. Identification of dinuclear aromatics in the gas oil fraction of Kuwait petroleum

    SciTech Connect

    Ijam, M.J.; Qatami, S.Y.A.; Arif, S.F.

    1988-08-01

    For several decades removal of aromatics from crude oil fractions (e.g. kerosene and lubricating oils) has been practiced in oil refining to produce fuels and lubricants of lower aromatic content and hence of improved quality. These aromatics are suitable raw materials for the manufacture of aromatic solvents, aromatic process oils, high octane gasoline, and as basic materials for making detergents, perfumes and dyes. Detailed study of molecular structure and substituent effects on the retention characteristics of aromatic hydrocarbons have been reported on alumina, silica and various chemically bonded silicas containing -C/sub 18/, -NH/sub 2/, -R(NH)/sub 2//sub 2/, -CN, RCN, RON and phenyl-mercuric acetate for the compound class (ring-numbered) high performance liquid chromatography (2, 3, 8, 12, 24, 28). Previous work in this laboratory has demonstrated that individual normal and branched aliphatic hydrocarbons from kerosene and light gas oil were isolated and identified. This paper describes the extension of this work to cover the separation and identification of aromatic ring classes (mono-, di-, and tri-aromatics) in the gas oil fraction of Kuwait petroleum. Characterization and identification of the major components in the dinuclear aromatics is our primary objective in this study.

  10. New Iterative Method for Fractional Gas Dynamics and Coupled Burger's Equations

    PubMed Central

    2015-01-01

    This paper presents the approximate analytical solutions to solve the nonlinear gas dynamics and coupled Burger's equations with fractional time derivative. By using initial values, the explicit solutions of the equations are solved by using a reliable algorithm. Numerical results show that the new iterative method is easy to implement and accurate when applied to time-fractional partial differential equations. PMID:25884018

  11. New iterative method for fractional gas dynamics and coupled Burger's equations.

    PubMed

    Al-Luhaibi, Mohamed S

    2015-01-01

    This paper presents the approximate analytical solutions to solve the nonlinear gas dynamics and coupled Burger's equations with fractional time derivative. By using initial values, the explicit solutions of the equations are solved by using a reliable algorithm. Numerical results show that the new iterative method is easy to implement and accurate when applied to time-fractional partial differential equations.

  12. Controlled initial surge despite high drug fraction and high solubility.

    PubMed

    Sarkar Das, Srilekha; Lucas, Anne D; Carlin, Alan S; Zheng, Jiwen; Patwardhan, Dinesh V; Saylor, David M

    2017-02-01

    Potential connections between release profiles and solvent evaporation rates alongside polymer chemistry were elucidated for the release of tetracycline hydrochloride from two different poly (d, l-lactide-co-glycolide) (PLGA) film matrices containing high drug fractions (50%, 30%, and 15%), and prepared at two distinct solvent evaporation rates. At highest tetracycline concentrations (50%), (i) the early release rates were ≤0.5 μg/min in all cases; (ii) release was linear from systems fabricated with lower lactic content and slower solvent evaporation rate and bimodal from systems fabricated with higher lactic content and faster evaporation rate; (iii) surface fractions covered by the drug were similar at both evaporation rates for 85:15 PLGA but very different for 50:50 PLGA, leading to unexpectedly reduced early release from 50:50 PLGA than from 85:15 PLGA when both the matrices were fabricated using a slower evaporation rate. These features remained unaffected in case of low drug concentration. Results suggested that during the formation of the drug-polymer microstructure, the combined effect of polymer chemistry and solvent evaporation rate sets apart the surface characteristics and the initial release profiles of systems containing high drug fraction, and an appropriate combination of these parameters may be utilized to control the early stage of drug release.

  13. Optimization of carbon dioxide supply in raceway reactors: Influence of carbon dioxide molar fraction and gas flow rate.

    PubMed

    Duarte-Santos, T; Mendoza-Martín, J L; Acién Fernández, F G; Molina, E; Vieira-Costa, J A; Heaven, S

    2016-07-01

    Influence of CO2 composition and gas flow rate to control pH in a pilot-scale raceway producing Scenedesmus sp. was studied. Light and temperature determined the biomass productivity whereas neither the CO2 molar fraction nor the gas flow rate used influenced it; because pH was always controlled and carbon limitation did not take place. The CO2 molar fraction and the gas flow rate influenced carbon loss in the system. At low CO2 molar fraction (2-6%) or gas flow rate (75-100l·min(-1)) the carbon efficiency in the sump was higher than 95%, 85% of the injected carbon being transformed into biomass. Conversely, at high CO2 molar fraction (14%) or gas flow rate (150l·min(-1)) the carbon efficiency in the sump was lower than 67%, 32% of the carbon being fixed as biomass. Analysis here reported allows the pH control to be optimized and production costs to be reduced by optimizing CO2 efficiency. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. High Excitation Gas and ISM

    NASA Technical Reports Server (NTRS)

    Peeters, E.; Martin-Hernandez, N. L.; Rodriguez-Fernandez, N. J.; Tielens, A. G. G. M.

    2004-01-01

    An overview is given of ISO results on regions of high excitation ISM and gas, i.e. HII regions, the Galactic Centre and Supernovae Remnants. IR emission due to fine-structure lines, molecular hydrogen, silicates, polycyclic aromatic hydrocarbons and dust are summarized, their diagnostic capabilities illustrated and their implications highlighted.

  15. High pressure gas metering project

    SciTech Connect

    Tripp, L.R.

    1980-07-07

    The initial research and development of a system that uses high pressure helium gas to pressurize vessels over a wide range of pressurization rates, vessel volumes, and maximum test pressures are described. A method of controlling the mass flow rate in a test vessel was developed by using the pressure difference across a capillary tube. The mass flow rate is related to the pressurization rate through a real gas equation of state. The resulting mass flow equation is then used in a control algorithm. Plots of two typical pressurization tests run on a manually operated system are included.

  16. Ancient carbon and noble gas fractionation. [in carbonaceous meteorites and terrestrial kerogen

    NASA Technical Reports Server (NTRS)

    Frick, U.; Chang, S.

    1977-01-01

    Noble gases in ancient terrestrial kerogen and meteoritic carbonaceous residues are compared in terms of their elemental fractionation with respect to atmospheric and the cosmic reservoirs, respectively. Fractionation factors for the heavy noble gases are almost identical in both types of samples. Therefore, some features of the interaction between carbon phases and noble gases in very different environments of origin appear to be similar. These findings underscore the plausibility of the meteoritic carbonaceous residues as a noble gas carrier and as a novel vehicle for achieving the elemental fractionation required to derive the planetary noble gas pattern from cosmic abundances.

  17. IONIZED GAS IN THE FIRST 10 kpc OF THE INTERSTELLAR GALACTIC HALO: METAL ION FRACTIONS

    SciTech Connect

    Howk, J. Christopher; Consiglio, S. Michelle E-mail: smconsiglio@ucla.edu

    2012-11-10

    We present direct measures of the ionization fractions of several sulfur ions in the Galactic warm ionized medium (WIM). We obtained high-resolution ultraviolet absorption-line spectroscopy of post-asymptotic giant branch stars in the globular clusters Messier 3 [(l, b) = (42.{sup 0}2, +78.{sup 0}7), d = 10.2 kpc, and z = 10.0 kpc] and Messier 5 [(l, b) = (3.{sup 0}9, +46.{sup 0}8), d = 7.5 kpc, and z = +5.3 kpc] with the Hubble Space Telescope and Far Ultraviolet Spectroscopic Explorer to measure, or place limits on, the column densities of S I, S II, S III, S IV, S VI, and H I. These clusters also house millisecond pulsars, whose dispersion measures give an electron column density from which we infer the H II column in these directions. We find fractions of S{sup +2} in the WIM for the M 3 and M 5 sight lines x(S{sup +2}) {identical_to} N(S{sup +2})/N(S) = 0.33 {+-} 0.07 and 0.47 {+-} 0.09, respectively, with variations perhaps related to location. With negligible quantities of the higher ionization states, we conclude that S{sup +} and S{sup +2} account for all of the S in the WIM. We extend the methodology to study the ion fractions in the warm and hot ionized gas of the Milky Way, including the high ions Si{sup +3}, C{sup +3}, N{sup +4}, and O{sup +5}. The vast majority of the Galactic ionized gas is warm (T {approx} 10{sup 4} K) and photoionized (the WIM) or very hot (T > 4 Multiplication-Sign 10{sup 5} K) and collisionally ionized. The common tracer of ionized gas beyond the Milky Way, O{sup +5}, traces <1% of the total ionized gas mass of the Milky Way.

  18. Fractional field equations for highly improbable events

    NASA Astrophysics Data System (ADS)

    Kleinert, H.

    2013-06-01

    Free and weakly interacting particles perform approximately Gaussian random walks with collisions. They follow a second-quantized nonlinear Schrödinger equation, or relativistic versions of it. By contrast, the fields of strongly interacting particles extremize more involved effective actions obeying fractional wave equations with anomalous dimensions. Their particle orbits perform universal Lévy walks with heavy tails, in which rare events are much more frequent than in Gaussian random walks. Such rare events are observed in exceptionally strong windgusts, monster or rogue waves, earthquakes, and financial crashes. While earthquakes may destroy entire cities, the latter have the potential of devastating entire economies.

  19. Soot volume fraction in a piloted turbulent jet non-premixed flame of natural gas

    SciTech Connect

    Qamar, N.H.; Alwahabi, Z.T.; King, K.D.; Chan, Q.N.; Nathan, G.J.; Roekaerts, D.

    2009-07-15

    Planar laser-induced incandescence (LII) has been used to measure soot volume fraction in a well-characterised, piloted, turbulent non-premixed flame known as the ''Delft Flame III''. Simulated Dutch natural gas was used as the fuel to produce a flame closely matching those in which a wide range of previous investigations, both experimental and modelling, have been performed. The LII method was calibrated using a Santoro-style burner with ethylene as the fuel. Instantaneous and time-averaged data of the axial and radial soot volume fraction distributions of the flame are presented here along with the Probability Density Functions (PDFs) and intermittency. The PDFs were found to be well-characterised by a single exponential distribution function. The distribution of soot was found to be highly intermittent, with intermittency typically exceeding 97%, which increases measurement uncertainty. The instantaneous values of volume fraction are everywhere less than the values in strained laminar flames. This is consistent with the soot being found locally in strained flame sheets that are convected and distorted by the flow. (author)

  20. Further characterization of particulate fractions from lysed cell envelopes of Halobacterium halobium and isolation of gas vacuole membranes.

    PubMed

    Toeckenius, W; Kunau, W H

    1968-08-01

    Lysates of cell envelopes from Halobacterium halobium have been separated into four fractions. A soluble, colorless fraction (I) containing protein, hexosamines, and no lipid is apparently derived from the cell wall. A red fraction (II), containing approximately 40 per cent lipid, 60 per cent protein, and a small amount of hexosamines consists of cell membrane disaggregated into fragments of small size. A third fraction (III) of purple color consists of large membrane sheets and has a very similar composition to II, containing the same classes of lipids but no hexosamines; its buoyant density is 1.18 g/ml. The fourth fraction (IV) has a buoyant density of 1.23 g/ml and contains the "intracytoplasmic membranes." These consist mainly of protein, and no lipid can be extracted with chloroform-methanol. Fractions I and II, which result from disaggregation of cell wall and cell membrane during lysis, contain a high proportion of dicarboxyl amino acids; this is in good agreement with the assumption that disruption of the cell envelope upon removal of salt is due to the high charge density. The intracytoplasmic membranes (IV) represent the gas vacuole membranes in the collapsed state. In a number of mutants that have lost the ability to form gas vacuoles, no vacuole membranes or any structure that could be related to them has been found.

  1. FURTHER CHARACTERIZATION OF PARTICULATE FRACTIONS FROM LYSED CELL ENVELOPES OF HALOBACTERIUM HALOBIUM AND ISOLATION OF GAS VACUOLE MEMBRANES

    PubMed Central

    Stoeckenius, Walther; Kunau, Wolf H.

    1968-01-01

    Lysates of cell envelopes from Halobacterium halobium have been separated into four fractions. A soluble, colorless fraction (I) containing protein, hexosamines, and no lipid is apparently derived from the cell wall. A red fraction (II), containing approximately 40 per cent lipid, 60 per cent protein, and a small amount of hexosamines consists of cell membrane disaggregated into fragments of small size. A third fraction (III) of purple color consists of large membrane sheets and has a very similar composition to II, containing the same classes of lipids but no hexosamines; its buoyant density is 1.18 g/ml. The fourth fraction (IV) has a buoyant density of 1.23 g/ml and contains the "intracytoplasmic membranes." These consist mainly of protein, and no lipid can be extracted with chloroform-methanol. Fractions I and II, which result from disaggregation of cell wall and cell membrane during lysis, contain a high proportion of dicarboxyl amino acids; this is in good agreement with the assumption that disruption of the cell envelope upon removal of salt is due to the high charge density. The intracytoplasmic membranes (IV) represent the gas vacuole membranes in the collapsed state. In a number of mutants that have lost the ability to form gas vacuoles, no vacuole membranes or any structure that could be related to them has been found. PMID:5664208

  2. Dense Gas Fraction and Star-formation Efficiency Variations in the Antennae Galaxies

    NASA Astrophysics Data System (ADS)

    Bigiel, F.; Leroy, A. K.; Blitz, L.; Bolatto, A. D.; da Cunha, E.; Rosolowsky, E.; Sandstrom, K.; Usero, A.

    2015-12-01

    We use the Combined Array for Research in Millimeter-wave Astronomy (CARMA) millimeter interferometer to map the Antennae Galaxies (NGC 4038/39), tracing the bulk of the molecular gas via the 12CO(1-0) line and denser molecular gas via the high density transitions HCN(1-0), HCO+(1-0), CS(2-1), and HNC(1-0). We detect bright emission from all tracers in both the two nuclei and three locales in the overlap region between the two nuclei. These three overlap region peaks correspond to previously identified “supergiant molecular clouds.” We combine the CARMA data with Herschel infrared (IR) data to compare observational indicators of the star formation efficiency (star formation rate/H2 ∝ IR/CO), dense gas fraction (HCN/CO), and dense gas star formation efficiency (IR/HCN). Regions within the Antennae show ratios consistent with those seen for entire galaxies, but these ratios vary by up to a factor of six within the galaxy. The five detected regions vary strongly in both their integrated intensities and these ratios. The northern nucleus is the brightest region in millimeter-wave line emission, while the overlap region is the brightest part of the system in the IR. We combine the CARMA and Herschel data with ALMA CO data to report line ratio patterns for each bright point. CO shows a declining spectral line energy distribution, consistent with previous studies. HCO+ (1-0) emission is stronger than HCN (1-0) emission, perhaps indicating either more gas at moderate densities or higher optical depth than is commonly seen in more advanced mergers.

  3. DENSE GAS FRACTION AND STAR FORMATION EFFICIENCY VARIATIONS IN THE ANTENNAE GALAXIES

    SciTech Connect

    Bigiel, F.; Leroy, A. K.; Blitz, L.; Bolatto, A. D.; Da Cunha, E.; Rosolowsky, E.; Sandstrom, K.; Usero, A.

    2015-12-20

    We use the Combined Array for Research in Millimeter-wave Astronomy (CARMA) millimeter interferometer to map the Antennae Galaxies (NGC 4038/39), tracing the bulk of the molecular gas via the {sup 12}CO(1–0) line and denser molecular gas via the high density transitions HCN(1–0), HCO{sup +}(1–0), CS(2–1), and HNC(1–0). We detect bright emission from all tracers in both the two nuclei and three locales in the overlap region between the two nuclei. These three overlap region peaks correspond to previously identified “supergiant molecular clouds.” We combine the CARMA data with Herschel infrared (IR) data to compare observational indicators of the star formation efficiency (star formation rate/H{sub 2} ∝ IR/CO), dense gas fraction (HCN/CO), and dense gas star formation efficiency (IR/HCN). Regions within the Antennae show ratios consistent with those seen for entire galaxies, but these ratios vary by up to a factor of six within the galaxy. The five detected regions vary strongly in both their integrated intensities and these ratios. The northern nucleus is the brightest region in millimeter-wave line emission, while the overlap region is the brightest part of the system in the IR. We combine the CARMA and Herschel data with ALMA CO data to report line ratio patterns for each bright point. CO shows a declining spectral line energy distribution, consistent with previous studies. HCO{sup +} (1–0) emission is stronger than HCN (1–0) emission, perhaps indicating either more gas at moderate densities or higher optical depth than is commonly seen in more advanced mergers.

  4. Sparger Effects on Gas Volume Fraction Distributions in Vertical Bubble-Column Flows as Measured by Gamma-Densitometry Tomography

    SciTech Connect

    GEORGE,DARIN L.; SHOLLENBERGER,KIM ANN; TORCZYNSKI,JOHN R.

    2000-01-18

    Gamma-densitometry tomography is applied to study the effect of sparger hole geometry, gas flow rate, column pressure, and phase properties on gas volume fraction profiles in bubble columns. Tests are conducted in a column 0.48 m in diameter, using air and mineral oil, superficial gas velocities ranging from 5 to 30 cm s{sup -1}, and absolute column pressures from 103 to 517 kPa. Reconstructed gas volume fraction profiles from two sparger geometries are presented. The development length of the gas volume fraction profile is found to increase with gas flow rate and column pressure. Increases in gas flow rate increase the local gas volume fraction preferentially on the column axis, whereas increases in column pressure produce a uniform rise in gas volume fraction across the column. A comparison of results from the two spargers indicates a significant change in development length with the number and size of sparger holes.

  5. Determination of void fraction in two phase liquid-gas flow using gamma absorption

    NASA Astrophysics Data System (ADS)

    Zych, M.; Hanus, R.; Jaszczur, M.; Strzępowicz, A.; Petryka, L.; Mastej, W.

    2016-09-01

    Full description of a two-phase liquid-gas flow requires the designation of lot parameters. First one, which describes which part of the pipeline is fulfilled by the gas, is the void fraction. Moreover the share of gas in a flowing mixture determines the structure of the flow and also affects the velocity of the individual phases. In that case void fraction can be determined by use the gamma absorption method, as well as other flow parameters may be evaluated by the same equipment. In addition the article presents the calibration of radiometric set, which consists of gamma radiation source Am-241 and scintillation probe NaI(Tl), for determination of the void fraction, illustrated by exemplary results of the described method application to various structures of air-water flow in the horizontal pipeline.

  6. Solar-wind krypton and solid/gas fractionation in the early solar nebula

    NASA Technical Reports Server (NTRS)

    Wiens, Roger C.; Burnett, D. S.; Neugebauer, M.; Pepin, R. O.

    1991-01-01

    The solar-system Kr abundance is calculated from solar-wind noble-gas ratios, determined previously by low-temperature oxidations of lunar ilmenite grains, normalized to Si by spacecraft solar-wind measurements. The estimated Kr-83 abundance of 4.1 + or - 1.5 per million Si atoms is within uncertainty of estimates assuming no fractionation, determined from CI-chondrite abundances of surrounding elements. This is significant because it is the first such constraint on solid/gas fractionation, though the large uncertainty only confines it to somewhat less than a factor of two.

  7. ORBITAL STRUCTURE OF MERGER REMNANTS. I. EFFECT OF GAS FRACTION IN PURE DISK MERGERS

    SciTech Connect

    Hoffman, Loren; Cox, Thomas J.; Dutta, Suvendra; Hernquist, Lars

    2010-11-01

    Since the violent relaxation in hierarchical merging is incomplete, elliptical galaxies retain a wealth of information about their formation pathways in their present-day orbital structure. Recent advances in integral field spectroscopy, multi-slit infrared spectroscopy, and triaxial dynamical modeling techniques have greatly improved our ability to harvest this information. A variety of observational and theoretical evidence indicates that gas-rich major mergers play an important role in the formation of elliptical galaxies. We simulate 1:1 disk mergers at seven different initial gas fractions (f{sub gas}) ranging from 0% to 40%, using a version of the TreeSPH code Gadget-2 that includes radiative heating and cooling, star formation, and feedback from supernovae and active galactic nuclei. We classify the stellar orbits in each remnant and construct radial profiles of the orbital content, intrinsic shape, and orientation. The dissipationless remnants are typically prolate-triaxial, dominated by box orbits within r{sub c} {approx} 1.5 R{sub e} , and by tube orbits in their outer parts. As f{sub gas} increases, the box orbits within r{sub c} are increasingly replaced by a population of short-axis tubes (z-tubes) with near zero net rotation, and the remnants become progressively more oblate and round. The long-axis tube (x-tube) orbits are highly streaming and relatively insensitive to f{sub gas}, implying that their angular momentum is retained from the dynamically cold initial conditions. Outside r{sub c} , the orbital structure is essentially unchanged by the gas. For f{sub gas} {approx}> 15%, gas that retains its angular momentum during the merger re-forms a disk that appears in the remnants as a highly streaming z-tube population superimposed on the hot z-tube distribution formed by the old stars. In the 15%-20% gas remnants, this population appears as a kinematically distinct core (KDC) within a system that is slowly rotating or dominated by minor-axis rotation

  8. Cryogenic fractionator gas as stripping gas of fines slurry in a coking and gasification process

    DOEpatents

    DeGeorge, Charles W.

    1981-01-01

    In an integrated coking and gasification process wherein a stream of fluidized solids is passed from a fluidized bed coking zone to a second fluidized bed and wherein entrained solid fines are recovered by a scrubbing process and wherein the resulting solids-liquid slurry is stripped with a stripping gas to remove acidic gases, at least a portion of the stripping gas comprises a gas comprising hydrogen, nitrogen and methane separated from the coker products.

  9. High Energy Gas Fracturing Test

    SciTech Connect

    Schulte, R.

    2001-02-27

    The Rocky Mountain Oilfield Testing Center (RMOTC) has recently completed two tests of a high-energy gas fracturing system being developed by Western Technologies of Crossville, Tennessee. The tests involved the use of two active wells located at the Naval Petroleum Reserve No. 3 (NPR-3), thirty-five miles north of Casper, Wyoming (See Figure 1). During the testing process the delivery and operational system was enhanced by RMOTC, Western Technologies, and commercial wireline subcontractors. RMOTC has assisted an industrial client in developing their technology for high energy gas fracturing to a commercial level. The modifications and improvements implemented during the technology testing process are instrumental in all field testing efforts at RMOTC. The importance of well selection can also be critical in demonstrating the success of the technology. To date, significant increases in well productivity have been clearly proven in well 63-TPX-10. Gross fluid production was initially raised by a factor of three. Final production rates increased by a factor of six with the use of a larger submersible pump. Well productivity (bbls of fluid per foot of drawdown) increased by a factor of 15 to 20. The above results assume that no mechanical damage has occurred to the casing or cast iron bridge plug which could allow well production from the Tensleep ''B'' sand. In the case of well 61-A-3, a six-fold increase in total fluid production was seen. Unfortunately, the increase is clouded by the water injection into the well that was necessary to have a positive fluid head on the propellant tool. No significant increase in oil production was seen. The tools which were retrieved from both 63-TPX-10 and 61-A-3 indicated a large amount of energy, similar to high gram perforating, had been expended downhole upon the formation face.

  10. Gas-phase Mechanisms of Sulfur Isotope Mass-independent Fractionation

    NASA Astrophysics Data System (ADS)

    Lyons, J. R.

    2006-12-01

    Mass-independent fractionation (MIF) in sulfur isotopes in ancient sulfur-bearing rocks (Farquhar et al. 2000a) is interpreted as evidence for gas-phase MIF processes in the early Earth atmosphere. This interpretation is made by analogy with oxygen isotope MIF in the modern atmosphere (produced during ozone formation), and by laboratory photolysis experiments on SO2 (Farquhar et al. 2001; Wing et al. 2004) that yield both elemental sulfur and sulfate with S MIF signatures at wavelengths above and below the SO2 dissociation limit. What is lacking is a quantitative understanding of the mechanisms of gas-phase S MIF. Quantification is essential in order to extract the full implications of sulfur MIF throughout Earth history, including for bacterial sulfate reduction processes which largely conserve D33S and D36S. Several sulfur MIF mechanisms are possible. The most obvious is the gas-phase thiozone reaction, which is isovalent to the ozone formation reaction. Ozone formation produces a well-known MIF signature in oxygen isotopes (Thiemens and Heidenreich 1983), and a symmetry-dependent non-RRKM mechanism has been proposed as the origin of O MIF (Gao and Marcus 2001). It is possible and perhaps likely that S3 formation also proceeds by a non-RRKM process. Data are lacking on isotopic (an even non-isotopic) rates of S3 formation, so it is not possible to make definitive statements about MIF in S3 at this time. However modeling results suggest that the vapor pressure of S2 is too low for gas-phase S3 formation to be significant. Two additional species that may exhibit a non-RRKM MIF signature are S2O2 and S4. Again, there is a lack of isotopomer-specific kinetic data for these reactions, and gas-phase formation of S4 is likely inconsequential. Perhaps the most obvious mechanism is simply the primary act of SO2 photolysis. The SO2 absorption spectrum is highly structured, with strong vibronic bands above and below the dissociation limit. In contrast H2S, with its mostly

  11. A simple methodological validation of the gas/particle fractionation of polycyclic aromatic hydrocarbons in ambient air

    PubMed Central

    Kim, Yong-Hyun; Kim, Ki-Hyun

    2015-01-01

    The analysis of polycyclic aromatic hydrocarbons (PAH) in ambient air requires the tedious experimental steps of both sampling and pretreatment (e.g., extraction or clean-up). To replace pre-existing conventional methods, a simple, rapid, and novel technique was developed to measure gas-particle fractionation of PAH in ambient air based on ‘sorbent tube-thermal desorption-gas chromatograph-mass spectrometer (ST-TD-GC-MS)’. The separate collection and analysis of ambient PAHs were achieved independently by two serially connected STs. The basic quality assurance confirmed good linearity, precision, and high sensitivity to eliminate the need for complicated pretreatment procedures with the detection limit (16 PAHs: 13.1 ± 7.04 pg). The analysis of real ambient PAH samples showed a clear fractionation between gas (two-three ringed PAHs) and particulate phases (five-six ringed PAHs). In contrast, for intermediate (four ringed) PAHs (fluoranthene, pyrene, benz[a]anthracene, and chrysene), a highly systematic/gradual fractionation was established. It thus suggests a promising role of ST-TD-GC-MS as measurement system in acquiring a reliable database of airborne PAH. PMID:26126962

  12. Estimation of the vapor pressure of petroleum distillate fractions from gas chromatographic data

    SciTech Connect

    Eggertsen, F.T.; Nygard, N.R.; Nickoley, L.D.

    1980-11-01

    The vapor pressure of petroleum distillate fractions is estimated conveniently by applying ideal gas and solution laws to gas chromatographic data. The vapor pressure is computed as a summation of the partial pressures for carbon number groups in the chromatogram, each partial pressure being derived as the product of mole fraction, determined from the chromatogram, and saturation pressure, calculated using the Antoine equation. A rapid method of computation with a programmable calculator was used. The method assumes approximate conformance to Raoult's and Dalton's laws relating to partial pressures from a solution. The results generally agree well with values obtained manometrically. Advantages of the method are the general availability of suitable gas chromatographic equipment, convenience and speed of the procedure and calculations, applicability over a wide range of volatility, freedom from temperature equilibration problems, and small sample requirement. 4 figures, 6 tables.

  13. High pressure synthesis gas fermentation

    SciTech Connect

    Not Available

    1991-01-01

    The purpose of this research project is to build and test a pressure fermentation system for the production of ethanol from synthesis gas. The fermenters, pumps, controls, and analytical system will be procured or fabricated and assembled in our laboratory. This system will then be used to determine the effects of high pressure on growth and ethanol production by clostridium ljungdahlii. The limits of cell concentration and mass transport relationships will be found in continuous stirred tank reactor and immobilized cell reactors. The minimum retention times and reactor volumes will be found for ethanol production in these reactors. Retention times of a few seconds are expected to result from these experiments. 2 figs., 2 tabs.

  14. Fractionation of Gibberellins in plant extracts by reverse phase high performance liquid chromatography

    SciTech Connect

    Jones, M.G.; Metzger, J.D.; Zeevaart, J.A.D.

    1980-02-01

    In studies on endogenous plant gibberellins (GAs), reverse phase (Bondapak C/sub 18/) high performance liquid chromatography (HPLC) has proved to be a useful method for the fractionation of plant extracts. The behavior of 18 authentic GAs in such a chromatographic system is described. The main factors determining chromatographic behavior are the degree and the position of hydroxylation of the GA. As an illustration of the use of reverse phase HPLC, the endogeneous GAs of immature seeds of Pharbitis nil L., strain Violet, were reinvestigated. The presence of gibberellins A/sub 3/, A/sub 5/, A/sub 17/, A/sub 20/, and A/sub 29/ was confirmed by gas-liquid chromatography-mass spectrometry. In addition, two other GAs, A/sub 19/ and A/sub 44/, were also identified in extracts of this material.

  15. An explicit high order method for fractional advection diffusion equations

    NASA Astrophysics Data System (ADS)

    Sousa, Ercília

    2014-12-01

    We propose a high order explicit finite difference method for fractional advection diffusion equations. These equations can be obtained from the standard advection diffusion equations by replacing the second order spatial derivative by a fractional operator of order α with 1<α≤2. This operator is defined by a combination of the left and right Riemann-Liouville fractional derivatives. We study the convergence of the numerical method through consistency and stability. The order of convergence varies between two and three and for advection dominated flows is close to three. Although the method is conditionally stable, the restrictions allow wide stability regions. The analysis is confirmed by numerical examples.

  16. High potential recovery -- Gas repressurization

    SciTech Connect

    Madden, M.P.

    1998-05-01

    The objective of this project was to demonstrate that small independent oil producers can use existing gas injection technologies, scaled to their operations, to repressurize petroleum reservoirs and increase their economic oil production. This report gives background information for gas repressurization technologies, the results of workshops held to inform small independent producers about gas repressurization, and the results of four gas repressurization field demonstration projects. Much of the material in this report is based on annual reports (BDM-Oklahoma 1995, BDM-Oklahoma 1996, BDM-Oklahoma 1997), a report describing the results of the workshops (Olsen 1995), and the four final reports for the field demonstration projects which are reproduced in the Appendix. This project was designed to demonstrate that repressurization of reservoirs with gas (natural gas, enriched gas, nitrogen, flue gas, or air) can be used by small independent operators in selected reservoirs to increase production and/or decrease premature abandonment of the resource. The project excluded carbon dioxide because of other DOE-sponsored projects that address carbon dioxide processes directly. Two of the demonstration projects, one using flue gas and the other involving natural gas from a deeper coal zone, were both technical and economic successes. The two major lessons learned from the projects are the importance of (1) adequate infrastructure (piping, wells, compressors, etc.) and (2) adequate planning including testing compatibility between injected gases and fluids, and reservoir gases, fluids, and rocks.

  17. High sensitivity gas spectroscopy of porous, highly scattering solids.

    PubMed

    Svensson, Tomas; Andersson, Mats; Rippe, Lars; Johansson, Jonas; Folestad, Staffan; Andersson-Engels, Stefan

    2008-01-01

    We present minimalistic and cost-efficient instrumentation employing tunable diode laser gas spectroscopy for the characterization of porous and highly scattering solids. The sensitivity reaches 3 x 10(-6) (absorption fraction), and the improvement with respect to previous work in this field is a factor of 10. We also provide the first characterization of the interference phenomenon encountered in high-resolution spectroscopy of turbid samples. Revealing that severe optical interference originates from the samples, we discuss important implications for system design. In addition, we introduce tracking coils and sample rotation as new and efficient tools for interference suppression. The great value of the approach is illustrated in an application addressing structural properties of pharmaceutical materials.

  18. Low Gas Fractions Connect Compact Star-Forming Galaxies to their z~2 Quiescent Descendants

    NASA Astrophysics Data System (ADS)

    Spilker, Justin; Bezanson, Rachel; Marrone, Daniel P.; Weiner, Benjamin J.; Whitaker, Katherine E.; Williams, Christina C.

    2017-01-01

    Early quiescent galaxies at z ~ 2 are known to be remarkably compact compared to their nearby counterparts. Possible progenitors of these systems include galaxies that are structurally similar, but are still rapidly forming stars. I will present Karl G. Jansky Very Large Array (VLA) observations of the CO(1-0) line towards three such compact, star-forming galaxies at z ~ 2.3, significantly detecting one. The VLA observations indicate baryonic gas fractions 5 times lower and gas depletion times 10 times shorter than normal, extended massive star-forming galaxies at these redshifts. At their current star formation rates, all three objects will deplete their gas reservoirs within 100Myr. These objects are among the most gas-poor objects observed at z > 2 and are outliers from standard gas scaling relations, a result which remains true regardless of assumptions about the CO-H2 conversion factor. Our observations are consistent with the idea that compact, star-forming galaxies are in a rapid state of transition to quiescence in tandem with the build-up of the z ~ 2 quenched population. In the detected compact galaxy, we see no evidence of rotation or that the CO-emitting gas is spatially extended relative to the stellar light. This casts doubt on recent suggestions that the gas in these compact galaxies is rotating and significantly extended compared to the stars. Instead, we suggest that, at least for this object, the gas is centrally concentrated, and only traces a small fraction of the total galaxy dynamical mass. I will conclude by discussing my ongoing efforts to characterize the gas and star forming properties of this unusual population of galaxies.

  19. Optimal q-homotopy analysis method for time-space fractional gas dynamics equation

    NASA Astrophysics Data System (ADS)

    Saad, K. M.; AL-Shareef, E. H.; Mohamed, Mohamed S.; Yang, Xiao-Jun

    2017-01-01

    It is well known that the homotopy analysis method is one of the most efficient methods for obtaining analytical or approximate semi-analytical solutions of both linear and non-linear partial differential equations. A more general form of HAM is introduced in this paper, which is called Optimal q-Homotopy Analysis Method (Oq-HAM). It has better convergence properties as compared with the usual HAM, due to the presence of fraction factor associated with the solution. The convergence of q-HAM is studied in details elsewhere (M.A. El-Tawil, Int. J. Contemp. Math. Sci. 8, 481 (2013)). Oq-HAM is applied to the non-linear homogeneous and non-homogeneous time and space fractional gas dynamics equations with initial condition. An optimal convergence region is determined through the residual error. By minimizing the square residual error, the optimal convergence control parameters can be obtained. The accuracy and efficiency of the proposed method are verified by comparison with the exact solution of the fractional gas dynamics equation. Also, it is shown that the Oq-HAM for the fractional gas dynamics equation is equivalent to the exact solution. We obtain graphical representations of the solutions using MATHEMATICA.

  20. Entropy, gas fraction, and temperature scaling relations of galaxy clusters and groups at R200

    NASA Astrophysics Data System (ADS)

    Wong, Ka-Wah; Irwin, Jimmy; Wik, Daniel R.; Sun, Ming; Sarazin, Craig L.; Fujita, Yutaka; Reiprich, Thomas

    2017-06-01

    With the growing number of galaxy clusters and groups measured in X-ray out to R200, it is possible to study the scaling relations between the enclosed gas fraction (fgas,200), entropy (K200), and temperature (T500), where the gas fraction and entropy are of great interest to constrain cosmological parameters and to understand the thermodynamic history of clusters or group formations, respectively. We will present scaling relations using 22 groups and clusters with published X-ray data in the literature. The power law slope of the K200-T200 relation is 0.638+/-0.205, which is shallower than the gravity heating-only baseline model of 1 and the K200-T200 relation. For massive clusters (T200 > 2 to 3 keV), K200 is lower than the baseline model, while no such entropy deficit was found for low-mass groups. The entropy deficit at R200 for massive clusters cannot be fully accounted for by the bias or deviation in the gas fraction. The enclosed baryon fraction at R200 is broadly consistent with the cosmic value. Physical properties of the outskirts of individual clusters, e.g., the nearest non-cool core cluster, Antlia, and a massive cluster, Abell 1689, will also be highlighted.

  1. Apparatus for measuring the local void fraction in a flowing liquid containing a gas

    DOEpatents

    Dunn, Patrick F.

    1981-01-01

    The local void fraction in liquid containing a gas is measured by placing an impedance-variation probe in the liquid, applying a controlled voltage or current to the probe, and measuring the probe current or voltage. A circuit for applying the one electrical parameter and measuring the other includes a feedback amplifier that minimizes the effect of probe capacitance and a digitizer to provide a clean signal. Time integration of the signal provides a measure of the void fraction, and an oscilloscope display also shows bubble size and distribution.

  2. Apparatus for measuring the local void fraction in a flowing liquid containing a gas

    DOEpatents

    Dunn, P.F.

    1979-07-17

    The local void fraction in liquid containing a gas is measured by placing an impedance-variation probe in the liquid, applying a controlled voltage or current to the probe, and measuring the probe current or voltage. A circuit for applying the one electrical parameter and measuring the other includes a feedback amplifier that minimizes the effect of probe capacitance and a digitizer to provide a clean signal. Time integration of the signal provides a measure of the void fraction, and an oscilloscope display also shows bubble size and distribution.

  3. Oxygen and sulfur isotope fractionation during methane dependent sulfate reduction in high pressure continuous incubation studies

    NASA Astrophysics Data System (ADS)

    Deusner, C.; Brunner, B.; Holler, T.; Widdel, F.; Ferdelman, T. G.

    2009-12-01

    The anaerobic oxidation of methane (AOM) coupled to sulfate reduction in marine sediments is an important sink in the global methane budget. However, many aspects of methane dependent sulfate reduction are not fully understood. We developed a novel high pressure biotechnical system to simulate marine conditions with high concentrations of dissolved gases, e.g. at gas seeps and gas hydrate systems. The system allows for batch, fed-batch and continuous gas-phase free incubation. We employ this system to study the kinetics and isotope fractionation during AOM at varying methane partial pressures up to 10 MPa. We present the results of long-term continuous and fed-batch incubations with highly active naturally enriched biomass from microbial mats from the Black Sea. During these experiments the methane partial pressure was increased stepwise from 0.1 to 10 MPa. The methane dependent sulfate reduction rate increased from 0.1 mmol/l/d to 3.5 mmol/l/d resulting from the increase in methane concentration and microbial growth. Sulfate reduction was negligible in the absence of methane. The sulfur and oxygen isotope fractionation during sulfate reduction was strongly influenced by the concentration of dissolved methane. Sulfur isotope fractionation was highest at low methane concentrations, and lowest at high methane concentrations. Relative to sulfate reduction rates, oxygen isotope exchange between sulfate and water was highest at low methane concentrations, and lowest at high methane concentrations.

  4. Low Gas Fractions Connect Compact Star-forming Galaxies to Their z ~ 2 Quiescent Descendants

    NASA Astrophysics Data System (ADS)

    Spilker, Justin S.; Bezanson, Rachel; Marrone, Daniel P.; Weiner, Benjamin J.; Whitaker, Katherine E.; Williams, Christina C.

    2016-11-01

    Early quiescent galaxies at z˜ 2 are known to be remarkably compact compared to their nearby counterparts. Possible progenitors of these systems include galaxies that are structurally similar, but are still rapidly forming stars. Here, we present Karl G. Jansky Very Large Array (VLA) observations of the CO(1-0) line toward three such compact, star-forming galaxies (SFGs) at z˜ 2.3, significantly detecting one. The VLA observations indicate baryonic gas fractions ≳ 5 times lower and gas depletion timescales ≳ 10 times shorter than normal, extended massive SFGs at these redshifts. At their current star formation rates, all three objects will deplete their gas reservoirs within 100 Myr. These objects are among the most gas-poor objects observed at z\\gt 2, and are outliers from standard gas scaling relations, a result that remains true regardless of assumptions about the CO-H2 conversion factor. Our observations are consistent with the idea that compact, SFGs are in a rapid state of transition to quiescence in tandem with the buildup of the z˜ 2 quenched population. In the detected compact galaxy, we see no evidence of rotation or that the CO-emitting gas is spatially extended relative to the stellar light. This casts doubt on recent suggestions that the gas in these compact galaxies is rotating and significantly extended compared to the stars. Instead, we suggest that, at least for this object, the gas is centrally concentrated, and only traces a small fraction of the total galaxy dynamical mass.

  5. Thermodynamics of a one-dimensional ideal gas with fractional exclusion statistics

    SciTech Connect

    Murthy, M.V.N.; Shankar, R. )

    1994-12-19

    We show that the particles in the Calogero-Sutherland model obey fractional exclusion statistics as defined by Haldane. We construct anyon number densities and derive the energy distribution function. We show that the partition function factorizes in the form characteristic of an ideal gas. The virial expansion is exactly computable and interestingly it is only the second virial coefficient that encodes the statistics information.

  6. Measurements of charge-state fractions following gas cells in beams of light negative ions

    SciTech Connect

    Grisham, L.R.; Post, D.E.; Johnson, B.M.; Jones, K.W.; Barrette, J.; Kruse, T.H.; Tserruya, I.; Da-Hai, W.

    1981-01-01

    We have measured neutral and charged particle fractions formed by passing beams of Li/sup -/, C/sup -/, O/sup -/, and Si/sup -/ at energies up to 7 MeV through gas cells of N/sub 2/, Ar, or CO/sub 2/. We discuss the implications of these results for the design of neutralizers to yield light atom beams for tokamak heating or current drive.

  7. Metallicity evolution, metallicity gradients, and gas fractions at z ~ 3.4

    NASA Astrophysics Data System (ADS)

    Troncoso, P.; Maiolino, R.; Sommariva, V.; Cresci, G.; Mannucci, F.; Marconi, A.; Meneghetti, M.; Grazian, A.; Cimatti, A.; Fontana, A.; Nagao, T.; Pentericci, L.

    2014-03-01

    We used near-infrared integral field spectroscopic observations from the AMAZE and LSD ESO programs to constrain the metallicity in a sample of 40 star-forming galaxies at 3 < z < 5 (most of which are at z ~ 3.4). We measured metallicities by exploiting strong emission-line diagnostics. We found that a significant fraction of star-forming galaxies at z ~ 3.4 deviate from the fundamental metallicity relation (FMR), with a metallicity of up to a factor of ten lower than expected according to the FMR. This deviation does not correlate with the dynamical properties of the galaxy or with the presence of interactions. To investigate the origin of the metallicity deviation in more detail, we also inferred information on the gas content by inverting the Schmidt-Kennicutt relation, assuming that the latter does not evolve out to z ~ 3.4. In agreement with recent CO observational data, we found that in contrast with the steeply rising trend at 0 < z < 2, the gas fraction in massive galaxies remains constant, with an indication of a marginal decline at 2 < z < 3.5. When combined with the metallicity information, we infer that to explain the low metallicity and gas content in z ~ 3.4 galaxies, both prominent outflows and massive pristine gas inflows are needed. In ten galaxies we can also spatially resolve the metallicity distribution. We found that the metallicity generally anticorrelates with the distribution of star formation and with the gas surface density. We discuss these findings in terms of pristine gas inflows toward the center, and outflows of metal-rich gas from the center toward the external regions. Based on data obtained at the VLT through the ESO programs 178.B-0838, 075.A-0300 and 076.A-0711.Appendices are available in electronic form at http://www.aanda.org

  8. Galaxy Cluster Gas Mass Fractions From Sunyaev-Zeldovich Effect Measurements: Constraints on Omega(M)

    NASA Technical Reports Server (NTRS)

    Grego, Laura; Carlstrom, John E.; Reese, Erik D.; Holder, Gilbert P.; Holzapfel, William L.; Joy, Marshall K.; Mohr, Joseph J.; Patel, Sandeep

    2001-01-01

    Using sensitive centimeter-wave receivers mounted on the Owens Valley Radio Observatory and Berkeley-Illinois-Maryland-Association millimeter arrays, we have obtained interferometric measurements of the Sunyaev-Zeldovich(SZ) effect toward massive galaxy clusters. We use the SZ data to determine the pressure distribution of the cluster gas and, in combination with published X-ray temperatures, to infer the gas mass and total gravitational mass of 18 clusters. The gas mass fraction, f(g), is calculated for each cluster and is extrapolated to the fiducial radius r(500) using the results of numerical simulations. The mean f(g) within r(500) is 0.081(+ 0.009 / - 0.011) per h(100) (statistical uncertainty at 68% confidence level, assuming Omega(M) = 0.3, Omega(Lambda) = 0.7). We discuss possible sources of systematic errors in the mean f(sub g) measurement. We derive an upper limit for Omega(M) from this sample under the assumption that the mass composition of clusters within r(500) reflects the universal mass composition: Omega(M)h is less than or equal to Omega(B)/f(g). The gas mass fractions depend on cosmology through the angular diameter distance and the r(500) correction factors. For a flat universe (Omega(Lambda) is identical with 1 - Omega(M)) and h = 0.7, we find the measured gas mass fractions are consistent with Omega(M) is less than 0.40, at 68% confidence. Including estimates of the baryons contained in galaxies and the baryons which failed to become bound during the cluster formation process, we find Omega(M) is approximately equal to 0.25.

  9. Galaxy Cluster Gas Mass Fractions From Sunyaev-Zeldovich Effect Measurements: Constraints on Omega(M)

    NASA Technical Reports Server (NTRS)

    Grego, Laura; Carlstrom, John E.; Reese, Erik D.; Holder, Gilbert P.; Holzapfel, William L.; Joy, Marshall K.; Mohr, Joseph J.; Patel, Sandeep

    2001-01-01

    Using sensitive centimeter-wave receivers mounted on the Owens Valley Radio Observatory and Berkeley-Illinois-Maryland-Association millimeter arrays, we have obtained interferometric measurements of the Sunyaev-Zeldovich(SZ) effect toward massive galaxy clusters. We use the SZ data to determine the pressure distribution of the cluster gas and, in combination with published X-ray temperatures, to infer the gas mass and total gravitational mass of 18 clusters. The gas mass fraction, f(g), is calculated for each cluster and is extrapolated to the fiducial radius r(500) using the results of numerical simulations. The mean f(g) within r(500) is 0.081(+ 0.009 / - 0.011) per h(100) (statistical uncertainty at 68% confidence level, assuming Omega(M) = 0.3, Omega(Lambda) = 0.7). We discuss possible sources of systematic errors in the mean f(sub g) measurement. We derive an upper limit for Omega(M) from this sample under the assumption that the mass composition of clusters within r(500) reflects the universal mass composition: Omega(M)h is less than or equal to Omega(B)/f(g). The gas mass fractions depend on cosmology through the angular diameter distance and the r(500) correction factors. For a flat universe (Omega(Lambda) is identical with 1 - Omega(M)) and h = 0.7, we find the measured gas mass fractions are consistent with Omega(M) is less than 0.40, at 68% confidence. Including estimates of the baryons contained in galaxies and the baryons which failed to become bound during the cluster formation process, we find Omega(M) is approximately equal to 0.25.

  10. The gas distribution in the high-redshift cluster MS 1054-0321

    NASA Astrophysics Data System (ADS)

    Mirakhor, M. S.; Birkinshaw, M.

    2016-04-01

    We investigate the gas mass distribution in the high-redshift cluster MS 1054-0321 using Chandra X-ray and One Centimetre Receiver array Sunyaev-Zel'dovich (SZ) effect data. We use a superposition of offset β-type models to describe the composite structure of MS 1054-0321. We find gas mass fractions f_{gas}^{X {-}ray} = 0.087_{-0.001}^{+0.005} and f_{gas}^SZ=0.094_{-0.001}^{+0.003} for the (main) eastern component of MS 1054-0321 using X-ray or SZ data, but f_{gas}^{X {-}ray}=0.030_{-0.014}^{+0.010} for the western component. The gas mass fraction for the eastern component is in agreement with some results reported in the literature, but inconsistent with the cosmic baryon fraction. The low-gas mass fraction for the western component is likely to be a consequence of gas stripping during the ongoing merger. The gas mass fraction of the integrated system is 0.060_{-0.009}^{+0.004}: we suggest that the missing baryons from the western component are present as hot diffuse gas which is poorly represented in existing X-ray images. The missing gas could appear in sensitive SZ maps.

  11. Compact, high energy gas laser

    DOEpatents

    Rockwood, Stephen D.; Stapleton, Robert E.; Stratton, Thomas F.

    1976-08-03

    An electrically pumped gas laser amplifier unit having a disc-like configuration in which light propagation is radially outward from the axis rather than along the axis. The input optical energy is distributed over a much smaller area than the output optical energy, i.e., the amplified beam, while still preserving the simplicity of parallel electrodes for pumping the laser medium. The system may thus be driven by a comparatively low optical energy input, while at the same time, owing to the large output area, large energies may be extracted while maintaining the energy per unit area below the threshold of gas breakdown.

  12. FT-Raman and photoacoustic infrared spectroscopy of Syncrude heavy gas oil distillation fractions.

    PubMed

    Michaelian, Kirk H; Hall, Robert H; Bulmer, J Tim

    2003-03-01

    FT-Raman and photoacoustic (PA) infrared spectra of six distillation fractions derived from Syncrude heavy gas oil (HGO), which has a boiling range from 343 to 524 degrees C, were analyzed in detail in this study. Most of the information on the fingerprint region (200-1,800 cm(-1)) is provided by the FT-Raman spectra, which display approximately 30 bands that are assignable to functional groups in alkanes or aromatics. Monocyclic, bicyclic and tricyclic aromatics in the six fractions were also monitored using bands in this region. The C-H stretching region in both the FT-Raman and PA infrared spectra of the HGO distillation fractions was analyzed according to a curve-fitting algorithm used in previous investigations of samples with lower boiling points. The PA spectra of the HGO fractions were also analyzed by integration. The curve-fitting results show that the frequencies of the 11 Raman and 8 infrared bands used to model the aliphatic (approximately 2,775-3,000 cm(-1)) parts of the respective spectra are approximately constant across the entire HGO boiling range. These band positions are consistent with the results obtained in earlier studies of other distillation fractions obtained from Syncrude sweet blend. Both curve-fitting and integration show that the respective proportions of CH(2) and CH(3) groups do not vary significantly within the HGO region.

  13. FT-Raman and photoacoustic infrared spectroscopy of syncrude light gas oil distillation fractions.

    PubMed

    Michaelian, Kirk H; Hall, Robert H; Bulmer, J Tim

    2003-11-01

    FT-Raman and photoacoustic (PA) infrared spectra of 12 distillation fractions derived from Syncrude light gas oil (LGO), which has a boiling range from 195 to 343 degrees C, were analyzed in detail in this study. In the fingerprint region (200-1800 cm(-1)) most of the information is obtained from the FT-Raman spectra, which display 36 bands that are assignable to various alkyl or aryl functional groups. Monocyclic, bicyclic and tricyclic aromatics in the 12 fractions were also characterized using Raman bands in this region. The corresponding section of the infrared spectra is much simpler, displaying a relatively small number of bands due to either aromatic or aliphatic CH(n) (n=1, 2 or 3) groups. The Cz.sbnd;H stretching region in both FT-Raman and PA infrared spectra of the LGO distillation fractions was curve-fitted according to procedures established in previous investigations of Syncrude samples with various boiling ranges. The PA spectra of the LGO fractions were also analyzed using an accepted integration strategy that requires no a priori assumptions with regard to the number of constituent bands or their shapes. The curve-fitting results show that the frequencies of the 11 Raman and eight infrared bands used to model the aliphatic ( approximately 2775-3000 cm(-1)) parts of the respective spectra decrease systematically as the median boiling points of the LGO fractions increase. These band positions are consistent with those determined in earlier studies of other distillation fractions. Both curve fitting and integration show that the abundance of CH(2) groups increases at the expense of CH(3) groups as the boiling points of the fractions increase within the LGO region.

  14. Fundamental studies on kinetic isotope effect (KIE) of hydrogen isotope fractionation in natural gas systems

    USGS Publications Warehouse

    Ni, Y.; Ma, Q.; Ellis, G.S.; Dai, J.; Katz, B.; Zhang, S.; Tang, Y.

    2011-01-01

    Based on quantum chemistry calculations for normal octane homolytic cracking, a kinetic hydrogen isotope fractionation model for methane, ethane, and propane formation is proposed. The activation energy differences between D-substitute and non-substituted methane, ethane, and propane are 318.6, 281.7, and 280.2cal/mol, respectively. In order to determine the effect of the entropy contribution for hydrogen isotopic substitution, a transition state for ethane bond rupture was determined based on density function theory (DFT) calculations. The kinetic isotope effect (KIE) associated with bond rupture in D and H substituted ethane results in a frequency factor ratio of 1.07. Based on the proposed mathematical model of hydrogen isotope fractionation, one can potentially quantify natural gas thermal maturity from measured hydrogen isotope values. Calculated gas maturity values determined by the proposed mathematical model using ??D values in ethane from several basins in the world are in close agreement with similar predictions based on the ??13C composition of ethane. However, gas maturity values calculated from field data of methane and propane using both hydrogen and carbon kinetic isotopic models do not agree as closely. It is possible that ??D values in methane may be affected by microbial mixing and that propane values might be more susceptible to hydrogen exchange with water or to analytical errors. Although the model used in this study is quite preliminary, the results demonstrate that kinetic isotope fractionation effects in hydrogen may be useful in quantitative models of natural gas generation, and that ??D values in ethane might be more suitable for modeling than comparable values in methane and propane. ?? 2011 Elsevier Ltd.

  15. Fundamental studies on kinetic isotope effect (KIE) of hydrogen isotope fractionation in natural gas systems

    NASA Astrophysics Data System (ADS)

    Ni, Yunyan; Ma, Qisheng; Ellis, Geoffrey S.; Dai, Jinxing; Katz, Barry; Zhang, Shuichang; Tang, Yongchun

    2011-05-01

    Based on quantum chemistry calculations for normal octane homolytic cracking, a kinetic hydrogen isotope fractionation model for methane, ethane, and propane formation is proposed. The activation energy differences between D-substitute and non-substituted methane, ethane, and propane are 318.6, 281.7, and 280.2 cal/mol, respectively. In order to determine the effect of the entropy contribution for hydrogen isotopic substitution, a transition state for ethane bond rupture was determined based on density function theory (DFT) calculations. The kinetic isotope effect (KIE) associated with bond rupture in D and H substituted ethane results in a frequency factor ratio of 1.07. Based on the proposed mathematical model of hydrogen isotope fractionation, one can potentially quantify natural gas thermal maturity from measured hydrogen isotope values. Calculated gas maturity values determined by the proposed mathematical model using δD values in ethane from several basins in the world are in close agreement with similar predictions based on the δ 13C composition of ethane. However, gas maturity values calculated from field data of methane and propane using both hydrogen and carbon kinetic isotopic models do not agree as closely. It is possible that δD values in methane may be affected by microbial mixing and that propane values might be more susceptible to hydrogen exchange with water or to analytical errors. Although the model used in this study is quite preliminary, the results demonstrate that kinetic isotope fractionation effects in hydrogen may be useful in quantitative models of natural gas generation, and that δD values in ethane might be more suitable for modeling than comparable values in methane and propane.

  16. Solubility controlled noble gas fractionation during magmatic degassing: Implications for noble gas compositions of primary melts of OIB and MORB

    NASA Astrophysics Data System (ADS)

    Yamamoto, Junji; Burnard, Pete G.

    2005-02-01

    Noble gas abundances in basaltic glasses from ocean islands (OIBs) are generally lower than those of mid-oceanic ridge basalts (MORBs), contrary to most geodynamic models which usually require that the source of OIBs is less degassed (resulting in higher primordial noble gas abundances) and more trace element enriched (resulting in higher radiogenic noble gas abundances) than the MORB source. Therefore, noble gas abundances in OIBs are often thought to have been reduced by extensive gas loss from the magma before eruption. The extent of magmatic degassing can be tested as it will cause characteristic changes in the composition of the volatiles; notably the 4He/ 40Ar* ratio (where 40Ar* is 40Ar corrected for atmospheric contamination) will increase in residual volatiles due to the higher solubility of He relative to Ar. The degree of He-Ar fractionation for a given fraction of gas loss depends on the ratio of the solubilities, S He/S Ar, which is sensitive to (among other things) the CO 2 and H 2O content of the basalt at the time of degassing. From a global database of OIB and MORB glasses, we show that 4He/ 40Ar* ratios of MORB glasses are broadly consistent with degassing of a magma with an initial 40Ar of ≈1.5 × 10 -5 ccSTP/g, i.e., similar to that of the "popping rock." However, OIB glasses generally have lower 40Ar* concentration for a given 4He/ 40Ar*. While this would appear to require lower 40Ar* abundances in the undegassed OIB magmas, the higher volatile contents of OIBs will reduce S He/S Ar (relative to MORBs) during degassing. By modeling S He/S Ar in OIBs, it is possible to show that extensive degassing of OIBs can occur without dramatically increasing the 4He/ 40Ar* ratio. We show that undegassed 40Ar concentrations of OIB magmas were probably similar to those of MORBs.

  17. DISRUPTION MITIGATION WITH HIGH-PRESSURE NOBLE GAS INJECTION

    SciTech Connect

    WHYTE, DG; JERNIGAN, TC; HUMPHREYS, DA; HYATT, AW; LASNIER, CJ; PARKS, PB; EVANS, TE; TAYLOR, PL; KELLMAN, AG; GRAY, DS; HOLLMANN, EM

    2002-10-01

    OAK A271 DISRUPTION MITIGATION WITH HIGH-PRESSURE NOBLE GAS INJECTION. High-pressure gas jets of neon and argon are used to mitigate the three principal damaging effects of tokamak disruptions: thermal loading of the divertor surfaces, vessel stress from poloidal halo currents and the buildup and loss of relativistic electrons to the wall. The gas jet penetrates as a neutral species through to the central plasma at its sonic velocity. The injected gas atoms increase up to 500 times the total electron inventory in the plasma volume, resulting in a relatively benign radiative dissipation of >95% of the plasma stored energy. The rapid cooling and the slow movement of the plasma to the wall reduce poloidal halo currents during the current decay. The thermally collapsed plasma is very cold ({approx} 1-2 eV) and the impurity charge distribution can include > 50% fraction neutral species. If a sufficient quantity of gas is injected, the neutrals inhibit runaway electrons. A physical model of radiative cooling is developed and validated against DIII-D experiments. The model shows that gas jet mitigation, including runaway suppression, extrapolates favorably to burning plasmas where disruption damage will be more severe. Initial results of real-time disruption detection triggering gas jet injection for mitigation are shown.

  18. Complete elution of vacuum gas oil resins by comprehensive high-temperature two-dimensional gas chromatography.

    PubMed

    Boursier, Laure; Souchon, Vincent; Dartiguelongue, Cyril; Ponthus, Jérémie; Courtiade, Marion; Thiébaut, Didier

    2013-03-08

    The development of efficient conversion processes requires extended knowledge on vacuum gas oils (VGOs). Among these processes, hydrocracking is certainly one of the best suited to meet the increasing demand on high quality diesel fuels. Most of refractory and inhibiting compounds towards hydrocracking and especially nitrogen containing compounds are contained in a fraction of the VGO called the resin fraction, which corresponds to the most polar fraction of a VGO obtained by liquid chromatography (LC) fractionation on a silica column. However, the lack of resolution observed through existing analytical methods does not allow a detailed characterization of these fractions. A recent study showed that comprehensive high temperature two-dimensional gas chromatography (HT-GC×GC) methods could be optimized in order to elute heavy compounds. This method was implemented for the analysis of VGO resin fractions and complete elution was reached. Firstly, the method was validated through repeatability, accuracy, linearity and response factors calculations. Four VGO resin fractions were analyzed and their HT-GC×GC simulated distillation curves were compared to their GC simulated distillation (GC-SimDist) curves. This comparison showed that the method allows complete elution of most of the analyzed VGO resin fractions. However, a detailed characterization of these fractions is not yet obtained due to the very large number of heteroatomic and aromatic species that a flame ionization detector can detect. Current work aims at increasing the selectivity of GC×GC by using heteroatom selective detectors in order to improve the characterization of such products.

  19. Highly Compressed Free Gas in Deep-Water Natural Gas Hydrate Systems

    NASA Astrophysics Data System (ADS)

    Barth, G. A.

    2006-12-01

    Natural gas, predominantly methane, is stored in a highly compact form within solid gas hydrate. The large volume of free gas that can be liberated by dissociation of hydrate (at standard surface conditions) is a prominent aspect of this potential energy resource. In contrast, the highly compressed state of free gas under pressure-temperature conditions found in deep-water marine settings is rarely noted. To facilitate comparison of gas quantities present within and below the hydrate stability zone in marine gas hydrate systems, particularly those in the deep-water Bering Sea basins, a suite of volume expansion ratios for 100% methane gas have been calculated. These ratios relate free gas volume under in-situ pressure (P) and temperature (T) conditions to free gas volume at standard surface conditions. The volume calculation is routine, using the Peng-Robinson equation of state (Peng and Robinson, 1976). Because most geophysical field studies aim to resolve the quantities of solid hydrate or free gas as a volume fraction of bulk rock in-situ, whereas gas resource volumes are reported as volume of free gas at STP, results here are presented as free gas volume ratios describing expansion between depth and surface conditions. This presentation also allows direct comparison with free gas yield of solid hydrate. Volume expansion ratio is presented for general reference for the pressure range 1 to 60 MPa and temperature range 0° to 80°C. (See USGS Open File Report 05-1451 online.) For pressures in the range 30 to 52 MPa and temperatures from 4° to 80°C, a more detailed evaluation of the P (water depth) and T (geotherm) effects on gas volumes has been undertaken. Ideal gas deviation factors, or z-factors, are also included. For free methane gas near the base of the hydrate stability zone at 360 m below seafloor in the Bering Sea, under conditions of 3,600 m water depth, 4°C seafloor temperature and 60°C/km geothermal gradient, the ratio of gas volume at standard

  20. Fuel Fraction Analysis of 500 MWth Gas Cooled Fast Reactor with Nitride (UN-PuN) Fuel without Refueling

    NASA Astrophysics Data System (ADS)

    Dewi Syarifah, Ratna; Su'ud, Zaki; Basar, Khairul; Irwanto, Dwi

    2017-01-01

    Nuclear Power Plant (NPP) is one of candidates which can support electricity demand in the world. The Generation IV NPP has fourth main objective, i.e. sustainability, economics competitiveness, safety and reliability, and proliferation and physical protection. One of Gen-IV reactor type is Gas Cooled Fast Reactor (GFR). In this study, the analysis of fuel fraction in small GFR with nitride fuel has been done. The calculation was performed by SRAC code, both Pij and CITATION calculation. SRAC2002 system is a code system applicable to analyze the neutronics of variety reactor type. And for the data library used JENDL-3.2. The step of SRAC calculation is fuel pin calculated by Pij calculation until the data homogenized, after it homogenized we calculate core reactor. The variation of fuel fraction is 40% up to 65%. The optimum design of 500MWth GFR without refueling with 10 years burn up time reach when radius F1:F2:F3 = 50cm:30cm:30cm and height F1:F2:F3 = 50cm:40cm:30cm, variation percentage Plutonium in F1:F2:F3 = 7%:10%:13%. The optimum fuel fraction is 41% with addition 2% Plutonium weapon grade mix in the fuel. The excess reactivity value in this case 1.848% and the k-eff value is 1.01883. The high burn up reached when the fuel fraction is low. In this study 41% fuel fraction produce faster fissile fuel, so it has highest burn-up level than the other fuel fraction.

  1. Energy use and greenhouse gas emissions from an algae fractionation process for producing renewable diesel

    SciTech Connect

    Pegallapati, Ambica K; Frank, Edward D.

    2016-09-01

    In one approach to algal biofuel production, lipids are extracted and converted to renewable diesel and non-lipid remnants are converted to biogas, which is used for renewable heat and power to support the process. Since biofuel economics benefit from increased fuel yield, the National Renewable Energy Laboratory analyzed an alternative pathway that extracts lipids and also makes ethanol from carbohydrates in the biomass. In this paper, we examine the environmental sustainability of this "fractionation pathway" through life-cycle analysis (LCA) of greenhouse gas emissions and energy use. When the feedstock productivity was 30 (18) g/m(2)/d, this pathway emitted 31 (36) gCO(2)e/MJ of total fuel, which is less than the emissions associated with conventional low sulfur petroleum diesel (96 gCO(2)e/MJ). The fractionation pathway performed well in this model despite the diversion of carbon to the ethanol fuel.

  2. The equivalent electrical permittivity of gas-solid mixtures at intermediate solid volume fractions.

    SciTech Connect

    Torczynski, John Robert; Ceccio, Steven Louis; Tortora, Paul Richard

    2005-07-01

    Several mixture models are evaluated for their suitability in predicting the equivalent permittivity of dielectric particles in a dielectric medium for intermediate solid volume fractions (0.4 to 0.6). Predictions of the Maxwell, Rayleigh, Bottcher and Bruggeman models are compared to computational simulations of several arrangements of solid particles in a gas and to the experimentally determined permittivity of a static particle bed. The experiment uses spherical glass beads in air, so air and glass permittivity values (1 and 7, respectively) are used with all of the models and simulations. The experimental system used to measure the permittivity of the static particle bed and its calibration are described. The Rayleigh model is found to be suitable for predicting permittivity over the entire range of solid volume fractions (0-0.6).

  3. Method of producing a high pressure gas

    DOEpatents

    Bingham, Dennis N.; Klingler, Kerry M.; Zollinger, William T.

    2006-07-18

    A method of producing a high pressure gas is disclosed and which includes providing a container; supplying the container with a liquid such as water; increasing the pressure of the liquid within the container; supplying a reactant composition such as a chemical hydride to the liquid under pressure in the container and which chemically reacts with the liquid to produce a resulting high pressure gas such as hydrogen at a pressure of greater than about 100 pounds per square inch of pressure; and drawing the resulting high pressure gas from the container.

  4. Low-temperature thermodynamics of the unitary Fermi gas: Superfluid fraction, first sound, and second sound

    SciTech Connect

    Salasnich, Luca

    2010-12-15

    We investigate the low-temperature thermodynamics of the unitary Fermi gas by introducing a model based on the zero-temperature spectra of both bosonic collective modes and fermonic single-particle excitations. We calculate the Helmholtz free energy and from it we obtain the entropy, the internal energy, and the chemical potential as a function of the temperature. By using these quantities and the Landau's expression for the superfluid density we determine analytically the superfluid fraction, the critical temperature, the first sound velocity, and the second sound velocity. We compare our analytical results with other theoretical predictions and experimental data of ultracold atoms and dilute neutron matter.

  5. Morphology and Molecular Gas Fractions of Local Luminous Infrared Galaxies as a Function of Infrared Luminosity and Merger Stage

    NASA Astrophysics Data System (ADS)

    Larson, K. L.; Sanders, D. B.; Barnes, J. E.; Ishida, C. M.; Evans, A. S.; U, V.; Mazzarella, J. M.; Kim, D.-C.; Privon, G. C.; Mirabel, I. F.; Flewelling, H. A.

    2016-07-01

    We present a new, detailed analysis of the morphologies and molecular gas fractions (MGFs) for a complete sample of 65 local luminous infrared galaxies from Great Observatories All-Sky Luminous Infrared Galaxies (LIRG) Survey using high resolution I-band images from The Hubble Space Telescope, the University of Hawaii 2.2 m Telescope and the Pan-STARRS1 Survey. Our classification scheme includes single undisturbed galaxies, minor mergers, and major mergers, with the latter divided into five distinct stages from pre-first pericenter passage to final nuclear coalescence. We find that major mergers of molecular gas-rich spirals clearly play a major role for all sources with {L}{IR}\\gt {10}11.5{L}⊙ ; however, below this luminosity threshold, minor mergers and secular processes dominate. Additionally, galaxies do not reach {L}{IR}\\gt {10}12.0{L}⊙ until late in the merger process when both disks are near final coalescence. The mean MGF ({MGF} = {M}{{{H}}2}/({M}* +{M}{{{H}}2})) for non-interacting and early-stage major merger LIRGs is 18 ± 2%, which increases to 33 ± 3%, for intermediate stage major merger LIRGs, consistent with the hypothesis that, during the early-mid stages of major mergers, most of the initial large reservoir of atomic gas (HI) at large galactocentric radii is swept inward where it is converted into molecular gas (H2).

  6. The efficacy and safety of subcision using CO2 gas combined with fractional laser for acne scars: Clinical and microscopic evaluation.

    PubMed

    Lee, Sang Jun; Suh, Dong Hye; Chang, Ka Yeon; Kim, Hyun Joo; Kim, Tae In; Jeong, Ki-Heon; Shin, Min Kyung; Song, Kye Yong

    2016-11-01

    Various modalities have been used to treat acne scars. CO2 fractional laser is an effective and commonly used treatment. CO2 gas injection into the dermis by needle with high pressure can cause fibrotic collagen breakage, producing the effects of subcision. CO2 also stimulates collagen synthesis by increasing neovascularization and releasing oxygen. This study evaluated the efficacy and the safety of the combined treatment with CO2 gas subcision and CO2 fractional laser for acne scars. Fourteen patients with acne scars were treated with three sessions of CO2 gas subcision at 2-week intervals and two sessions of fractional laser at 4-week interval. The clinical improvement was assessed using a 4-point scale. For histologic analysis, punch biopsy was performed before and after treatment in 10 patients. All patients experienced clinical improvements. Excellent, marked, moderate, and mild response was achieved in 1 (7%), 8 (57%), 4 (29%), and 1 patient (7%), respectively. Histologic evaluation of the biopsy specimens showed increased dermal collagen with dermal thickening and elastic fiber straightening in the reticular dermis after the treatment. The combination therapy with CO2 gas subcision and fractional laser was satisfactory and safe for treating acne scars. Abbreviation and acronym: CO2: Carbon dioxide GAS: Global assessment scale H&E: hematoxylin and eosin; SD: standard deviation.

  7. High dose bystander effects in spatially fractionated radiation therapy

    PubMed Central

    Asur, Rajalakshmi; Butterworth, Karl T.; Penagaricano, Jose A.; Prise, Kevin M.; Griffin, Robert J.

    2014-01-01

    Traditional radiotherapy of bulky tumors has certain limitations. Spatially fractionated radiation therapy (GRID) and intensity modulated radiotherapy (IMRT) are examples of advanced modulated beam therapies that help in significant reductions in normal tissue damage. GRID refers to the delivery of a single high dose of radiation to a large treatment area that is divided into several smaller fields, while IMRT allows improved dose conformity to the tumor target compared to conventional three-dimensional conformal radiotherapy. In this review, we consider spatially fractionated radiotherapy approaches focusing on GRID and IMRT, and present complementary evidence from different studies which support the role of radiation induced signaling effects in the overall radiobiological rationale for these treatments. PMID:24246848

  8. Magic Doping Fractions in High-Temperature Superconductors

    SciTech Connect

    Komiya, Seiki; Chen, Han-Dong; Zhang, Shou-Cheng; Ando, Yoichi; /CRIEPI, Tokyo

    2010-01-15

    We report hole-doping dependence of the in-plane resistivity {rho}{sub ab} in a cuprate superconductor La{sub 2-x}Sr{sub x}CuO{sub 4}, carefully examined using a series of high-quality single crystals. Our detailed measurements find a tendency towards charge ordering at particular rational hole doping fractions of 1/16, 3/32, 1/8, and 3/16. This observation appears to suggest a specific form of charge order and is most consistent with the recent theoretical prediction of the checkerboard-type ordering of the Cooper pairs at rational doping fractions x = (2m + 1)/2{sup n}, with integers m and n.

  9. High-rangeability ultrasonic gas flowmeter for monitoring flare gas.

    PubMed

    Mylvaganam, K S

    1989-01-01

    A transit-time ultrasonic gas flowmeter for high-rangeability requirements, such as those encountered in flare-gas flow-metering, is presented. The concept of ray rescue angle for the orientation of the ultrasonic transducers in single-beam transit-time ultrasonic flowmeters is introduced to overcome the problem of ultrasonic beam drift in high-velocity flows. To overcome problems associated with noise at high velocities, a chirp signal is used. To preserve the accuracy of the meter at low velocities near zero flow, a combination of chirp and continuous-wave signals is used to interrogate the flow. Overall system performance is presented, based on results from extensive wind-tunnel tests.

  10. Characterisation of the volatile fraction of aromatic caramel using heart-cutting multidimensional gas chromatography.

    PubMed

    Paravisini, Laurianne; Prot, Aurélie; Gouttefangeas, Cécile; Moretton, Cédric; Nigay, Henri; Dacremont, Catherine; Guichard, Elisabeth

    2015-01-15

    The first aim of our study was to improve characterisation of the volatile fraction of aromatic caramel by applying heart-cutting multidimensional gas chromatography coupled to mass spectrometry and olfactometry (MDGC-MS-O) on targeted odorant fractions. The second aim was to compare the volatile composition of two caramel samples, which differed in terms of their carbohydrate composition and cooking process. MDGC analyses enabled identification of 37 compounds (17 with the addition of pure standard) in the burnt sugar caramel, 20 of which were reported for the first time in caramel. Fifteen compounds were identified as odour-active and described using a range of attributes such as floral, roasted, spicy and almond. Furans, lactones and acids resulting from the thermal breakdown of sugars predominated in the volatile fraction of the burnt sugar caramel, due to the harsher cooking conditions. Finally, these results have enabled a clearer understanding of aromatic caramel as well as the identification of new compounds which might make an important contribution to its aroma. Copyright © 2014. Published by Elsevier Ltd.

  11. Gas-liquid Phase Distribution and Void Fraction Measurements Using the MRI

    NASA Technical Reports Server (NTRS)

    Daidzic, N. E.; Schmidt, E.; Hasan, M. M.; Altobelli, S.

    2004-01-01

    We used a permanent-magnet MRI system to estimate the integral and spatially- and/or temporally-resolved void-fraction distributions and flow patterns in gas-liquid two-phase flows. Air was introduced at the bottom of the stagnant liquid column using an accurate and programmable syringe pump. Air flow rates were varied between 1 and 200 ml/min. The cylindrical non-conducting test tube in which two-phase flow was measured was placed in a 2.67 kGauss MRI with MRT spectrometer/imager. Roughly linear relationship has been obtained for the integral void-fraction, obtained by volume-averaging of the spatially-resolved signals, and the air flow rate in upward direction. The time-averaged spatially-resolved void fraction has also been obtained for the quasi-steady flow of air in a stagnant liquid column. No great accuracy is claimed as this was an exploratory proof-of-concept type of experiment. Preliminary results show that MRI a non-invasive and non-intrusive experimental technique can indeed provide a wealth of different qualitative and quantitative data and is especially well suited for averaged transport processes in adiabatic and diabatic multi-phase and/or multi-component flows.

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

    PubMed

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

    2011-05-15

    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.

  13. Design of small gas cooled fast reactor with two region of natural Uranium fuel fraction

    NASA Astrophysics Data System (ADS)

    Ariani, Menik; Su'ud, Zaki; Waris, Abdul; Khairurrijal, Monado, Fiber; Sekimoto, Hiroshi; Nakayama, Sinsuke

    2012-06-01

    A design study of small Gas Cooled Fast Reactor with two region fuel has been performed. In this study, design GCFR with Helium coolant which can be continuously operated by supplying mixed Natural Uranium without fuel enrichment plant or fuel reprocessing plant. The active reactor cores are divided into two region fuel i.e. 60% fuel fraction of Natural Uranium as inner core and 65% fuel fraction of Natural Uranium as outer core. Each fuel core regions are subdivided into ten parts (region-1 until region-10) with the same volume in the axial direction. The fresh Natural Uranium initially put in region-1, after one cycle of 10 years of burn-up it is shifted to region-2 and the each region-1 filled by fresh Natural Uranium. This concept is basically applied to all regions in both cores area, i.e. shifted the core of ith region into i+1 region after the end of 10 years burn-up cycle. For the next cycles, we will add only Natural Uranium on each region-1. The burn-up calculation is performed using collision probability method PIJ (cell burn-up calculation) in SRAC code which then given eight energy group macroscopic cross section data to be used in two dimensional R-Z geometry multi groups diffusion calculation in CITATION code. This reactor can results power thermal 600 MWth with average power density i.e. 80 watt/cc. After reactor start-up the operation, furthermore reactor only needs Natural Uranium supply for continue operation along 100 years. This calculation result then compared with one region fuel design i.e. 60% and 65% fuel fraction. This core design with two region fuel fraction can be an option for fuel optimization.

  14. Photoionization and High Density Gas

    NASA Technical Reports Server (NTRS)

    Kallman, T.; Bautista, M.; White, Nicholas E. (Technical Monitor)

    2002-01-01

    We present results of calculations using the XSTAR version 2 computer code. This code is loosely based on the XSTAR v.1 code which has been available for public use for some time. However it represents an improvement and update in several major respects, including atomic data, code structure, user interface, and improved physical description of ionization/excitation. In particular, it now is applicable to high density situations in which significant excited atomic level populations are likely to occur. We describe the computational techniques and assumptions, and present sample runs with particular emphasis on high density situations.

  15. A New Void Fraction Measurement Method for Gas-Liquid Two-Phase Flow in Small Channels.

    PubMed

    Li, Huajun; Ji, Haifeng; Huang, Zhiyao; Wang, Baoliang; Li, Haiqing; Wu, Guohua

    2016-01-27

    Based on a laser diode, a 12 × 6 photodiode array sensor, and machine learning techniques, a new void fraction measurement method for gas-liquid two-phase flow in small channels is proposed. To overcome the influence of flow pattern on the void fraction measurement, the flow pattern of the two-phase flow is firstly identified by Fisher Discriminant Analysis (FDA). Then, according to the identification result, a relevant void fraction measurement model which is developed by Support Vector Machine (SVM) is selected to implement the void fraction measurement. A void fraction measurement system for the two-phase flow is developed and experiments are carried out in four different small channels. Four typical flow patterns (including bubble flow, slug flow, stratified flow and annular flow) are investigated. The experimental results show that the development of the measurement system is successful. The proposed void fraction measurement method is effective and the void fraction measurement accuracy is satisfactory. Compared with the conventional laser measurement systems using standard laser sources, the developed measurement system has the advantages of low cost and simple structure. Compared with the conventional void fraction measurement methods, the proposed method overcomes the influence of flow pattern on the void fraction measurement. This work also provides a good example of using low-cost laser diode as a competent replacement of the expensive standard laser source and hence implementing the parameter measurement of gas-liquid two-phase flow. The research results can be a useful reference for other researchers' works.

  16. TRANSFORMERLESS OPERATION OF DIII-D WITH HIGH BOOTSTRAP FRACTION

    SciTech Connect

    POLITZER,PA; HYATT,AW; LUCE,TC; MAHDAVI,MA; MURAKAMI,M; PERKINS,FW; PRATER,R; TURNBULL,AD; CASPER,TA; FERRON,JR; JAYAKUMAR,RJ; LAHAYE,RJ; LAZARUS,EA; PETTY,CC; WADE,MR

    2003-07-01

    OAK-B135 The authors have initiated an experimental program to address some of the questions associated with operation of a tokamak with high bootstrap current fraction under high performance conditions, without assistance from a transformer. In these discharges they have maintained stationary (or slowly improving) conditions for > 2.2 s at {beta}{sub N} {approx} {beta}{sub p} {approx} 2.8. Significant current overdrive, with dI/dt > 50 kA/s and zero or negative voltage, is sustained for over 0.7 s. The overdrive condition is usually ended with the appearance of MHD activity, which alters the profiles and reduces the bootstrap current. Characteristically these plasmas have 65%-80% bootstrap current, 25%-30% NBCD, and 5%-10% ECCD. Fully noninductive operation is essential for steady-state tokamaks. For efficient operation, the bootstrap current fraction must be close to 100%, allowing for a small additional ({approx} 10%) external current drive capability to be used for control. In such plasmas the current and pressure profiles are rightly coupled because J(r) is entirely determined by p(r) (or more accurately by the kinetic profiles). The pressure gradient in turn is determined by transport coefficients which depend on the poloidal field profile.

  17. Online Nanoflow Multidimensional Fractionation for High Efficiency Phosphopeptide Analysis*

    PubMed Central

    Ficarro, Scott B.; Zhang, Yi; Carrasco-Alfonso, Marlene J.; Garg, Brijesh; Adelmant, Guillaume; Webber, James T.; Luckey, C. John; Marto, Jarrod A.

    2011-01-01

    Despite intense, continued interest in global analyses of signaling cascades through mass spectrometry-based studies, the large-scale, systematic production of phosphoproteomics data has been hampered in-part by inefficient fractionation strategies subsequent to phosphopeptide enrichment. Here we explore two novel multidimensional fractionation strategies for analysis of phosphopeptides. In the first technique we utilize aliphatic ion pairing agents to improve retention of phosphopeptides at high pH in the first dimension of a two-dimensional RP-RP. The second approach is based on the addition of strong anion exchange as the second dimension in a three-dimensional reversed phase (RP)-strong anion exchange (SAX)-RP configuration. Both techniques provide for automated, online data acquisition, with the 3-D platform providing the highest performance both in terms of separation peak capacity and the number of unique phosphopeptide sequences identified per μg of cell lysate consumed. Our integrated RP-SAX-RP platform provides several analytical figures of merit, including: (1) orthogonal separation mechanisms in each dimension; (2) high separation peak capacity (3) efficient retention of singly- and multiply-phosphorylated peptides; (4) compatibility with automated, online LC-MS analysis. We demonstrate the reproducibility of RP-SAX-RP and apply it to the analysis of phosphopeptides derived from multiple biological contexts, including an in vitro model of acute myeloid leukemia in addition to primary polyclonal CD8+ T-cells activated in vivo through bacterial infection and then purified from a single mouse. PMID:21788404

  18. RESOLVE Survey Photometry and Volume-limited Calibration of the Photometric Gas Fractions Technique

    NASA Astrophysics Data System (ADS)

    Eckert, Kathleen D.; Kannappan, Sheila J.; Stark, David V.; Moffett, Amanda J.; Norris, Mark A.; Snyder, Elaine M.; Hoversten, Erik A.

    2015-09-01

    We present custom-processed ultraviolet, optical, and near-infrared photometry for the REsolved Spectroscopy of a Local VolumE (RESOLVE) survey, a volume-limited census of stellar, gas, and dynamical mass within two subvolumes of the nearby universe (RESOLVE-A and RESOLVE-B). RESOLVE is complete down to baryonic mass ˜ {10}9.1-9.3 {M}⊙ , probing the upper end of the dwarf galaxy regime. In contrast to standard pipeline photometry (e.g., SDSS), our photometry uses optimal background subtraction, avoids suppressing color gradients, and employs multiple flux extrapolation routines to estimate systematic errors. With these improvements, we measure brighter magnitudes, larger radii, bluer colors, and a real increase in scatter around the red sequence. Combining stellar mass estimates based on our optimized photometry with the nearly complete H i mass census for RESOLVE-A, we create new z = 0 volume-limited calibrations of the photometric gas fractions (PGF) technique, which predicts gas-to-stellar mass ratios (G/S) from galaxy colors and optional additional parameters. We analyze G/S-color residuals versus potential third parameters, finding that axial ratio is the best independent and physically meaningful third parameter. We define a “modified color” from planar fits to G/S as a function of both color and axial ratio. In the complete galaxy population, upper limits on G/S bias linear and planar fits. We therefore model the entire PGF probability density field, enabling iterative statistical modeling of upper limits and prediction of full G/S probability distributions for individual galaxies. These distributions have two-component structure in the red color regime. Finally, we use the RESOLVE-B 21 cm census to test several PGF calibrations, finding that most systematically under- or overestimate gas masses, but the full probability density method performs well.

  19. Interactions of soy protein fractions with high-methoxyl pectin.

    PubMed

    Lam, Monica; Paulsen, Paul; Corredig, Milena

    2008-06-25

    A protein-binding technique was employed to visualize, using scanning electron microscopy, the soy protein as well as the association between HMP and soy protein fractions. Image analysis indicated that at pH 7.5 and 3.5 soy protein isolate showed a bimodal distribution of sizes with an average [ d(0.5)] of about 0.05 microm, but at pH 3.8 the proteins formed larger aggregates than at high pH. Addition of HMP at pH 3.8 changed the surface charge of the particles from +20 to -15 mV. A small addition of HMP caused bridging of the pectin between soy protein aggregates and destabilization. With sufficient HMP, the suspensions showed improved stability to precipitation. The microscopy images are the first direct evidence of the interactions between soy proteins with high-methoxyl pectin (HMP).

  20. Modified algorithm for generating high volume fraction sphere packings

    NASA Astrophysics Data System (ADS)

    Valera, Roberto Roselló; Morales, Irvin Pérez; Vanmaercke, Simon; Morfa, Carlos Recarey; Cortés, Lucía Argüelles; Casañas, Harold Díaz-Guzmán

    2015-06-01

    Advancing front packing algorithms have proven to be very efficient in 2D for obtaining high density sets of particles, especially disks. However, the extension of these algorithms to 3D is not a trivial task. In the present paper, an advancing front algorithm for obtaining highly dense sphere packings is presented. It is simpler than other advancing front packing methods in 3D and can also be used with other types of particles. Comparison with respect to other packing methods have been carried out and a significant improvement in the volume fraction (VF) has been observed. Moreover, the quality of packings was evaluated with indicators other than VF. As additional advantage, the number of generated particles with the algorithm is linear with respect to time.

  1. Variegate galaxy cluster gas content: Mean fraction, scatter, selection effects, and covariance with X-ray luminosity

    NASA Astrophysics Data System (ADS)

    Andreon, S.; Wang, J.; Trinchieri, G.; Moretti, A.; Serra, A. L.

    2017-10-01

    We use a cluster sample selected independently of the intracluster medium content with reliable masses to measure the mean gas mass fraction and its scatter, the biases of the X-ray selection on gas mass fraction, and the covariance between the X-ray luminosity and gas mass. The sample is formed by 34 galaxy clusters in the nearby (0.050 < z < 0.135) Universe, mostly with 14 < log M500/M⊙ ≲ 14.5, and with masses calculated with the caustic technique. First, we found that integrated gas density profiles have similar shapes, extending earlier results based on subpopulations of clusters such as those that are relaxed or X-ray bright for their mass. Second, the X-ray unbiased selection of our sample allows us to unveil a variegate population of clusters; the gas mass fraction shows a scatter of 0.17 ± 0.04 dex, possibly indicating a quite variable amount of feedback from cluster to cluster, which is larger than is found in previous samples targeting subpopulations of galaxy clusters, such as relaxed or X-ray bright clusters. The similarity of the gas density profiles induces an almost scatterless relation between X-ray luminosity, gas mass, and halo mass, and modulates selection effects in the halo gas mass fraction: gas-rich clusters are preferentially included in X-ray selected samples. The almost scatterless relation also fixes the relative scatters and slopes of the LX-M and Mgas-M relations and makes core-excised X-ray luminosities and gas masses fully covariant. Therefore, cosmological or astrophysical studies involving X-ray or SZ selected samples need to account for both selection effects and covariance of the studied quantities with X-ray luminosity/SZ strength.

  2. High gas pressure effects on yeast.

    PubMed

    Espinasse, V; Perrier-Cornet, J-M; Marecat, A; Gervais, P

    2008-11-01

    Dried microorganisms are particularly resistant to high hydrostatic pressure effects. However, exposure to high pressures of nitrogen proved to be effective in inactivating dried yeasts. In this study, we tried to elucidate this mechanism on Saccharomyces cerevisiae. High-pressure treatments were performed using different inert gases at 150 MPa and 25 degrees C with holding time values up to 12 months. The influence of cell hydration was also investigated. For fully hydrated cells, pressurized gases had little specific effect: cell inactivation was mainly due to compression effects. However, dried cells were sensitive to high pressure of gases. In this latter case, two inactivation kinetics were observed. For holding time up to 1 h, the inactivation rate increased to 4 log and was linked to a loss of membrane integrity and the presence of damage on the cell wall. In such case cell inactivation would be due to gas sorption and desorption phenomena which would rupture dried cells during a fast pressure release. Gas sorption would occur in cell lipid phases. For longer holding times, the inactivation rate increased more slightly due to compression effects and/or to a slower gas sorption. Water therefore played a key role in cell sensitivity to fast gas pressure release. Two hypotheses were proposed to explain this phenomenon: the rigidity of vitrified dried cells and the presence of glassy solid phases which would favor intracellular gas expansion. Our results showed that dried microorganisms can be ruptured and inactivated by a fast pressure release with gases.

  3. Thermodynamics of ideal quantum gas with fractional statistics in D dimensions.

    PubMed

    Potter, Geoffrey G; Müller, Gerhard; Karbach, Michael

    2007-06-01

    We present exact and explicit results for the thermodynamic properties (isochores, isotherms, isobars, response functions, velocity of sound) of a quantum gas in dimensions D > or = 1 and with fractional exclusion statistics 0 < or = g < or =1 connecting bosons (g=0) and fermions (g=1) . In D=1 the results are equivalent to those of the Calogero-Sutherland model. Emphasis is given to the crossover between bosonlike and fermionlike features, caused by aspects of the statistical interaction that mimic long-range attraction and short-range repulsion. A phase transition along the isobar occurs at a nonzero temperature in all dimensions. The T dependence of the velocity of sound is in simple relation to isochores and isobars. The effects of soft container walls are accounted for rigorously for the case of a pure power-law potential.

  4. Efficient emulsification of viscous oils at high drop volume fraction.

    PubMed

    Tcholakova, Slavka; Lesov, Ivan; Golemanov, Konstantin; Denkov, Nikolai D; Judat, Sonja; Engel, Robert; Danner, Thomas

    2011-12-20

    It is shown experimentally in this study that the increase of drop volume fraction can be used as an efficient tool for emulsification of viscous oils in turbulent flow. In a systematic series of experiments, the effects of drop volume fraction and viscosity of the dispersed phase on the mean, d(32), and maximum, d(V95), diameters of the drops, formed during emulsification, are quantified. The volume fraction, Φ, of the dispersed oily phase is varied between 1% and 90%, and oils with viscosity varying between 3 and 10,000 mPa.s are studied. All experiments are performed at sufficiently high surfactant concentration, as to avoid possible drop-drop coalescence during emulsification. The analysis of the experimental data shows that there is a threshold drop volume fraction, Φ(TR), at which a transition from inertial turbulent regime into viscous turbulent regime of emulsification occurs, due to the increased overall viscosity of the emulsion. At Φ < Φ(TR), d(32) and d(V95) depend weakly on Φ and are well described by known theoretical expression for emulsification in inertial turbulent regime (Davies, Chem. Eng. Sci. 1985, 40, 839), which accounts for the effects of oil viscosity and interfacial tension. At Φ > Φ(TR), both d(32) and polydispersity of the formed emulsions decrease very significantly with the increase of Φ (for the oils with η(D) > 10 mPa.s). Thus, very efficient emulsification of the viscous oils is realized. Very surprisingly, a third regime of emulsification is observed in the range of concentrated emulsions with Φ > 75%, where the mean drop size and emulsion polydispersity are found experimentally to be very similar for all oils and surfactants studied-an experimental fact that does not comply with any of the existing models of drop breakup during emulsification. Possible mechanistic explanations of this result are discussed. The experimental data for semiconcentrated and concentrated emulsions with Φ > Φ(TR) are described by a simple

  5. Acquisition of void fraction of pulsatile gas-liquid two-phase flow in rectangular channel

    NASA Astrophysics Data System (ADS)

    Zhou, Bao; Liu, Jingxing; Tian, Jingda

    2013-07-01

    Experiment on two-phase pulsatile flow in a narrow rectangular visualization channel was carried out and photographed. Every frame was treated and restored as a black-white binary picture with the threshold of both gray-scale and gray-scale gradient. The gas-liquid interface in the binary pictures can be recognized well, including some very obvious interface, which either cannot be distinguished, or introduce big wrong-recognized area with the gray-scale threshold only. Then after such as `dilate', `erode', `fill', `filter' and so on operating, the binary pictures can reflect the twophase distinction situation in the experimental channel well; The instantaneous average void frictions at the length that the camera covered were calculated by counting the black and white pixels from the pictures. The average void fractions in the whole length of the test section were calculated with an iteration method. The average void fractions in the special length covered by camera and the ones in the whole length of the test section are different. The former shows that the void frictions dramatically frequently change, while the later at steady flow almost stay peace, at pulsatile flow change smoothly.

  6. Measure Guideline. High Efficiency Natural Gas Furnaces

    SciTech Connect

    Brand, L.; Rose, W.

    2012-10-01

    This measure guideline covers installation of high-efficiency gas furnaces, including: when to install a high-efficiency gas furnace as a retrofit measure; how to identify and address risks; and the steps to be used in the selection and installation process. The guideline is written for Building America practitioners and HVAC contractors and installers. It includes a compilation of information provided by manufacturers, researchers, and the Department of Energy as well as recent research results from the Partnership for Advanced Residential Retrofit (PARR) Building America team.

  7. Measure Guideline: High Efficiency Natural Gas Furnaces

    SciTech Connect

    Brand, L.; Rose, W.

    2012-10-01

    This Measure Guideline covers installation of high-efficiency gas furnaces. Topics covered include when to install a high-efficiency gas furnace as a retrofit measure, how to identify and address risks, and the steps to be used in the selection and installation process. The guideline is written for Building America practitioners and HVAC contractors and installers. It includes a compilation of information provided by manufacturers, researchers, and the Department of Energy as well as recent research results from the Partnership for Advanced Residential Retrofit (PARR) Building America team.

  8. High temperature gas-cooled reactor: gas turbine application study

    SciTech Connect

    Not Available

    1980-12-01

    The high-temperature capability of the High-Temperature Gas-Cooled Reactor (HTGR) is a distinguishing characteristic which has long been recognized as significant both within the US and within foreign nuclear energy programs. This high-temperature capability of the HTGR concept leads to increased efficiency in conventional applications and, in addition, makes possible a number of unique applications in both electrical generation and industrial process heat. In particular, coupling the HTGR nuclear heat source to the Brayton (gas turbine) Cycle offers significant potential benefits to operating utilities. This HTGR-GT Application Study documents the effort to evaluate the appropriateness of the HTGR-GT as an HTGR Lead Project. The scope of this effort included evaluation of the HTGR-GT technology, evaluation of potential HTGR-GT markets, assessment of the economics of commercial HTGR-GT plants, and evaluation of the program and expenditures necessary to establish HTGR-GT technology through the completion of the Lead Project.

  9. Systematic study of high molecular weight compounds in Amazonian plants by high temperature gas chromatography-mass spectrometry.

    PubMed

    de Siqueira, D S; Pereira, A S; Cabral, J A; Cid Ferreira, C A; de Aquino Neto, F R

    2000-01-01

    The fractions of hexane and dichloromethane extraction from marupá (Simaruba amara) and (Bertholletia excelsa) leaves were analyzed by HT-HRGC (high temperature high resolution gas chromatography) and HT-HRGC coupled to mass spectrometry (HT-HRGC-MS). Several compounds can be characterized including unusual high molecular weight compounds.

  10. Simultaneous imaging of fuel vapor mass fraction and gas-phase temperature inside gasoline sprays using two-line excitation tracer planar laser-induced fluorescence.

    PubMed

    Zigan, Lars; Trost, Johannes; Leipertz, Alfred

    2016-02-20

    This paper reports for the first time, to the best of our knowledge, on the simultaneous imaging of the gas-phase temperature and fuel vapor mass fraction distribution in a direct-injection spark-ignition (DISI) spray under engine-relevant conditions using tracer planar laser-induced fluorescence (TPLIF). For measurements in the spray, the fluorescence tracer 3-pentanone is added to the nonfluorescent surrogate fuel iso-octane, which is excited quasi-simultaneously by two different excimer lasers for two-line excitation LIF. The gas-phase temperature of the mixture of fuel vapor and surrounding gas and the fuel vapor mass fraction can be calculated from the two LIF signals. The measurements are conducted in a high-temperature, high-pressure injection chamber. The fluorescence calibration of the tracer was executed in a flow cell and extended significantly compared to the existing database. A detailed error analysis for both calibration and measurement is provided. Simultaneous single-shot gas-phase temperature and fuel vapor mass fraction fields are processed for the assessment of cyclic spray fluctuations.

  11. Hurricane risk mitigation - High Pressure Gas Facility

    NASA Technical Reports Server (NTRS)

    2008-01-01

    A worker pours concrete as part of a nitrogen risk mitigation project at the High Pressure Gas Facility at Stennis Space Center. The concrete slab will provide the foundation needed to place new pumps at the site and is part of ongoing hurricane-related mitigation work at Stennis.

  12. Hurricane risk mitigation - High Pressure Gas Facility

    NASA Image and Video Library

    2008-07-29

    A worker pours concrete as part of a nitrogen risk mitigation project at the High Pressure Gas Facility at Stennis Space Center. The concrete slab will provide the foundation needed to place new pumps at the site and is part of ongoing hurricane-related mitigation work at Stennis.

  13. Continuous high-power gas lasers

    NASA Technical Reports Server (NTRS)

    Hertzberg, A.

    1979-01-01

    High power gas laser concepts are discussed with emphasis on the role that fluid mechanics has played in their development. Consideration is given to three types of systems: gasdynamic lasers, HF supersonic diffusion lasers, and electric discharge lasers. Flow effects and aerodynamic windows in such lasers are briefly described. Future directions of research are outlined.

  14. Continuous high-power gas lasers

    NASA Technical Reports Server (NTRS)

    Hertzberg, A.

    1979-01-01

    High power gas laser concepts are discussed with emphasis on the role that fluid mechanics has played in their development. Consideration is given to three types of systems: gasdynamic lasers, HF supersonic diffusion lasers, and electric discharge lasers. Flow effects and aerodynamic windows in such lasers are briefly described. Future directions of research are outlined.

  15. Cauda equina tolerance to high-dose fractionated irradiation

    SciTech Connect

    Pieters, Richard S.; Niemierko, Andrzej; Fullerton, Barbara C.; Munzenrider, John E. . E-mail: jmunzenrider@partners.org

    2006-01-01

    Purpose: To report late neurologic toxicity rates and clinical outcomes for patients treated with high dose fractionated radiation therapy using three-dimensional treatment planning and combined proton and photon beams to portions of the cauda equina (L2-coccyx). Methods and Materials: Medical records of 53 patients treated to fields encompassing the cauda equina were reviewed for the onset of neurologic symptoms in the absence of local failure. All doses were normalized to equivalent dose delivered in 2-Gy fractions. Median cauda dose was 65.8 cobalt Gray equivalents (CGE) (range, 31.9-85.1). Median follow-up was 87 months (range, 14-217 months). Results: Nineteen patients experienced local recurrences, and 13 others had neurologic toxicity. A total of 54% (i.e., 7/13) of the toxicities occurred 5 years or more after treatment. Median caudal dose was 73.7 CGE in the group with neurologic toxicity, and 55.6 CGE in those without. On multivariate actuarial analysis, cauda dose and gender were statistically significant for neurotoxicity at p = 0.002 and p = 0.017, respectively. The estimated tolerance doses 5 years from treatment, TD 5/5 and TD 50/5, were 55 CGE and 72 CGE, respectively, for males and 67 CGE and 84 CGE for females. The tolerance doses were about 8 CGE lower when estimated at 10 years from treatment. Disease-free survival rates at 5 and 10 years were 66% and 53%, respectively. Conclusions: This study suggests that the probability of neurotoxicity is a relatively steep function of dose to cauda equina (slope {gamma}{sub 5} = approximately 3). The cauda equina tolerance is greater for females than males by about 11 CGE (at 2 CGE per fraction). Extended follow-up is necessary to accurately assess neurologic damage and then differentiate that phenomenon from local recurrence; the traditional 5-year assessment has limited meaning in this population. Local control remains an issue for these patients, even with the radical doses used.

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

    SciTech Connect

    Dell'Anna, L.; Mazzarella, G.; Salasnich, L.

    2011-09-15

    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.

  17. High-order fractional partial differential equation transform for molecular surface construction

    PubMed Central

    Hu, Langhua; Chen, Duan; Wei, Guo-Wei

    2013-01-01

    Fractional derivative or fractional calculus plays a significant role in theoretical modeling of scientific and engineering problems. However, only relatively low order fractional derivatives are used at present. In general, it is not obvious what role a high fractional derivative can play and how to make use of arbitrarily high-order fractional derivatives. This work introduces arbitrarily high-order fractional partial differential equations (PDEs) to describe fractional hyperdiffusions. The fractional PDEs are constructed via fractional variational principle. A fast fractional Fourier transform (FFFT) is proposed to numerically integrate the high-order fractional PDEs so as to avoid stringent stability constraints in solving high-order evolution PDEs. The proposed high-order fractional PDEs are applied to the surface generation of proteins. We first validate the proposed method with a variety of test examples in two and three-dimensional settings. The impact of high-order fractional derivatives to surface analysis is examined. We also construct fractional PDE transform based on arbitrarily high-order fractional PDEs. We demonstrate that the use of arbitrarily high-order derivatives gives rise to time-frequency localization, the control of the spectral distribution, and the regulation of the spatial resolution in the fractional PDE transform. Consequently, the fractional PDE transform enables the mode decomposition of images, signals, and surfaces. The effect of the propagation time on the quality of resulting molecular surfaces is also studied. Computational efficiency of the present surface generation method is compared with the MSMS approach in Cartesian representation. We further validate the present method by examining some benchmark indicators of macromolecular surfaces, i.e., surface area, surface enclosed volume, surface electrostatic potential and solvation free energy. Extensive numerical experiments and comparison with an established surface model

  18. High-order fractional partial differential equation transform for molecular surface construction.

    PubMed

    Hu, Langhua; Chen, Duan; Wei, Guo-Wei

    2013-01-01

    Fractional derivative or fractional calculus plays a significant role in theoretical modeling of scientific and engineering problems. However, only relatively low order fractional derivatives are used at present. In general, it is not obvious what role a high fractional derivative can play and how to make use of arbitrarily high-order fractional derivatives. This work introduces arbitrarily high-order fractional partial differential equations (PDEs) to describe fractional hyperdiffusions. The fractional PDEs are constructed via fractional variational principle. A fast fractional Fourier transform (FFFT) is proposed to numerically integrate the high-order fractional PDEs so as to avoid stringent stability constraints in solving high-order evolution PDEs. The proposed high-order fractional PDEs are applied to the surface generation of proteins. We first validate the proposed method with a variety of test examples in two and three-dimensional settings. The impact of high-order fractional derivatives to surface analysis is examined. We also construct fractional PDE transform based on arbitrarily high-order fractional PDEs. We demonstrate that the use of arbitrarily high-order derivatives gives rise to time-frequency localization, the control of the spectral distribution, and the regulation of the spatial resolution in the fractional PDE transform. Consequently, the fractional PDE transform enables the mode decomposition of images, signals, and surfaces. The effect of the propagation time on the quality of resulting molecular surfaces is also studied. Computational efficiency of the present surface generation method is compared with the MSMS approach in Cartesian representation. We further validate the present method by examining some benchmark indicators of macromolecular surfaces, i.e., surface area, surface enclosed volume, surface electrostatic potential and solvation free energy. Extensive numerical experiments and comparison with an established surface model

  19. ON THE CLUSTER PHYSICS OF SUNYAEV-ZEL'DOVICH AND X-RAY SURVEYS. III. MEASUREMENT BIASES AND COSMOLOGICAL EVOLUTION OF GAS AND STELLAR MASS FRACTIONS

    SciTech Connect

    Battaglia, N.; Bond, J. R.; Pfrommer, C.; Sievers, J. L.

    2013-11-10

    Gas masses tightly correlate with the virial masses of galaxy clusters, allowing for a precise determination of cosmological parameters by means of X-ray surveys. However, the gas mass fractions (f{sub gas}) at the virial radius (R{sub 200}) derived from recent Suzaku observations are considerably larger than the cosmic mean, calling into question the accuracy of cosmological parameters. Here, we use a large suite of cosmological hydrodynamical simulations to study measurement biases of f{sub gas}. We employ different variants of simulated physics, including radiative gas physics, star formation, and thermal feedback by active galactic nuclei, which we show is able to arrest overcooling and to result in constant stellar mass fractions for redshifts z < 1. Computing the mass profiles in 48 angular cones, we find anisotropic gas and total mass distributions that imply an angular variance of f{sub gas} at the level of 30%. This anisotropy originates from the recent formation epoch of clusters and from the strong internal baryon-to-dark-matter density bias. In the most extreme cones, f{sub gas} can be biased high by a factor of two at R{sub 200} in massive clusters (M{sub 200} ∼ 10{sup 15} M{sub ☉}), thereby providing an explanation for high f{sub gas} measurements by Suzaku. While projection lowers this factor, there are other measurement biases that may (partially) compensate. At R{sub 200}, f{sub gas} is biased high by 20% when assuming hydrostatic equilibrium masses, i.e., neglecting the kinetic pressure, and by another ∼10%-20% due to the presence of density clumping. At larger radii, both measurement biases increase dramatically. While the cluster sample variance of the true f{sub gas} decreases to a level of 5% at R{sub 200}, the sample variance that includes both measurement biases remains fairly constant at the level of 10%-20%. The constant redshift evolution of f{sub gas} within R{sub 500} for massive clusters is encouraging for using gas masses to

  20. Properties of pinto beans air-classified high starch fraction and its extrudates

    USDA-ARS?s Scientific Manuscript database

    Pinto beans were milled and air classified to obtain a high starch fraction, and then extruded. Properties of non-extruded high starch fraction (NE-HSF) and extruded high starch fraction (E-HSF) were compared with whole pinto flour (WPF). Composition (d.b.) of WPF was 4% ash, 1.6% extractable lipid ...

  1. Gas film disturbance characteristics analysis of high-speed and high-pressure dry gas seal

    NASA Astrophysics Data System (ADS)

    Chen, Yuan; Jiang, Jinbo; Peng, Xudong

    2016-08-01

    The dry gas seal(DGS) has been widely used in high parameters centrifugal compressor, but the intense vibrations of shafting, especially in high-speed condition, usually result in DGS's failure. So the DGS's ability of resisting outside interference has become a determining factor of the further development of centrifugal compressor. However, the systematic researches of which about gas film disturbance characteristics of high parameters DGS are very little. In order to study gas film disturbance characteristics of high-speed and high-pressure spiral groove dry gas seal(S-DGS) with a flexibly mounted stator, rotor axial runout and misalignment are taken into consideration, and the finite difference method and analytical method are used to analyze the influence of gas film thickness disturbance on sealing performance parameters, what's more, the effects of many key factors on gas film thickness disturbance are systematically investigated. The results show that, when sealed pressure is 10.1MPa and seal face average linear velocity is 107.3 m/s, gas film thickness disturbance has a significant effect on leakage rate, but has relatively litter effect on open force; Excessively large excitation amplitude or excessively high excitation frequency can lead to severe gas film thickness disturbance; And it is beneficial to assure a smaller gas film thickness disturbance when the stator material density is between 3.1 g/cm3 to 8.4 g/cm3; Ensuring sealing performance while minimizing support axial stiffness and support axial damping can help to improve dynamic tracking property of dry gas seal. The proposed research provides the instruction to optimize dynamic tracking property of the DGS.

  2. Cooled membrane for high sensitivity gas sampling.

    PubMed

    Jiang, Ruifen; Pawliszyn, Janusz

    2014-04-18

    A novel sample preparation method that combines the advantages of high surface area geometry and cold surface effect was proposed to achieve high sensitivity gas sampling. To accomplish this goal, a device that enables the membrane to be cooled down was developed for sampling, and a gas chromatograph-mass spectrometer was used for separation and quantification analysis. Method development included investigation of the effect of membrane temperature, membrane size, gas flow rate and humidity. Results showed that high sensitivity for equilibrium sampling, such as limonene sampling in the current study could be achieved by either cooling down the membrane and/or using a large volume extraction phase. On the other hand, for pre-equilibrium extraction, in which the extracted amount was mainly determined by membrane surface area and diffusion coefficient, high sensitivity could be obtained by using thinner membranes with a larger surface and/or a higher sampling flow rate. In addition, humidity showed no significant influence on extraction efficiency, due to the absorption property of the liquid extraction phase. Next, the limit of detection (LOD) was found, and the reproducibility of the developed cooled membrane gas sampling method was evaluated. Results showed that LODs with a membrane diameter of 19mm at room temperature sampling were 9.2ng/L, 0.12ng/L, 0.10ng/L for limonene, cinnamaldehyde and 2-pentadecanone, respectively. Intra- and inter-membrane sampling reproducibility revealed RSD% lower than 8% and 13%, respectively. Results uniformly demonstrated that the proposed cooled membrane device could serve as an alternative powerful tool for future gas sampling.

  3. Role of organic matter fractions in the Montney tight gas reservoir quality

    NASA Astrophysics Data System (ADS)

    Sanei, Hamed; Wood, James M.; Haeri Ardakani, Omid; Clarkson, Chris R.

    2015-04-01

    This study presents a new approach in Rock-Eval analysis to quantify various organic matter fractions in unconventional reservoirs. The results of study on core samples from the Triassic Montney Formation tight gas reservoir in the Western Canadian Sedimentary Basin show that operationally-defined S1 and S2 hydrocarbon peaks from conventional Rock-Eval analysis may not adequately characterize the organic constituents of unconventional reservoir rocks. Modification of the thermal recipe for Rock-Eval analysis, in conjunction with manual peak integration, provides important information with significance for the evaluation of reservoir quality. An adapted Rock-Eval method, herein called the extended slow heating (ESH) cycle, was developed in which the heating rate was slowed to 10°C per minute over an extended temperature range (150 to 650°C). For Montney core samples from the wet gas window, this method provided quantitative distinctions between major organic matter components of the rock. We show that the traditional S1 and S2 peaks can now be quantitatively divided into three components: (S1ESH) free light oil, (S2a ESH) condensed hydrocarbon residue (CHCR), and (S2b ESH + residual carbon) solid bitumen (refractory, consolidated bitumen/pyrobitumen). The majority of the total organic carbon (TOC) in the studied Montney core samples consists of solid bitumen that represents a former liquid oil phase which migrated into the larger paleo-intergranular pore spaces. Subsequent physicochemical changes to the oil environment led to the precipitation of asphaltene aggregates. Further diagenetic and thermal maturity processes consolidated these asphaltene aggregates into "lumps" of solid bitumen (or pyrobitumen at higher thermal maturity). Solid bitumen obstructs porosity and hinders fluid flow, and thus shows strong negative correlations with reservoir qualities such as porosity and pore throat size. We also find a strong positive correlation between the quantities of

  4. Pressurized laboratory experiments show no stable carbon isotope fractionation of methane during gas hydrate dissolution and dissociation.

    PubMed

    Lapham, Laura L; Wilson, Rachel M; Chanton, Jeffrey P

    2012-01-15

    The stable carbon isotopic ratio of methane (δ(13)C-CH(4)) recovered from marine sediments containing gas hydrate is often used to infer the gas source and associated microbial processes. This is a powerful approach because of distinct isotopic fractionation patterns associated with methane production by biogenic and thermogenic pathways and microbial oxidation. However, isotope fractionations due to physical processes, such as hydrate dissolution, have not been fully evaluated. We have conducted experiments to determine if hydrate dissolution or dissociation (two distinct physical processes) results in isotopic fractionation. In a pressure chamber, hydrate was formed from a methane gas source at 2.5 MPa and 4 °C, well within the hydrate stability field. Following formation, the methane source was removed while maintaining the hydrate at the same pressure and temperature which stimulated hydrate dissolution. Over the duration of two dissolution experiments (each ~20-30 days), water and headspace samples were periodically collected and measured for methane concentrations and δ(13)C-CH(4) while the hydrate dissolved. For both experiments, the methane concentrations in the pressure chamber water and headspace increased over time, indicating that the hydrate was dissolving, but the δ(13)C-CH(4) values showed no significant trend and remained constant, within 0.5‰. This lack of isotope change over time indicates that there is no fractionation during hydrate dissolution. We also investigated previous findings that little isotopic fractionation occurs when the gas hydrate dissociates into gas bubbles and water due to the release of pressure. Over a 2.5 MPa pressure drop, the difference in the δ(13)C-CH(4) was <0.3‰. We have therefore confirmed that there is no isotope fractionation when the gas hydrate dissociates and demonstrated that there is no fractionation when the hydrate dissolves. Therefore, measured δ(13)C-CH(4) values near gas hydrates are not affected

  5. A new contactless impedance sensor for void fraction measurement of gas-liquid two-phase flow

    NASA Astrophysics Data System (ADS)

    Ji, Haifeng; Chang, Ya; Huang, Zhiyao; Wang, Baoliang; Li, Haiqing

    2016-12-01

    With impedance elimination principle and phase sensitive demodulation (PSD) technique, this work aims to develop a new contactless impedance sensor, which is suitable for the void fraction measurement of gas-liquid two-phase flow. The impedance elimination principle is used to overcome the unfavorable influences of the coupling capacitances, i.e. the capacitive reactances of the coupling capacitances are eliminated by the inductive reactance of an introduced inductor. PSD technique is used to implement the impedance measurement. Unlike the conventional conductance/impedance sensors which use the equivalent conductance (the real part of the impedance) or the amplitude of the impedance of gas-liquid two-phase flow, the new contactless impedance sensor makes full use of the total impedance information of gas-liquid two-phase flow (including the amplitude, the real part and the imaginary part of the impedance, especially the imaginary part) to implement the void fraction measurement. As a preliminary study, to verify the effectiveness of the new contactless impedance sensor, two prototypes (with different inner diameters of 17.0 mm and 22.0 mm) are developed and experiments are carried out. Two typical flow patterns (bubble flow and stratified flow) of gas-liquid two-phase flow are investigated. The experimental results show that the new contactless impedance sensor is successful and effective. Compared with the conventional conductance/impedance sensors, the new contactless impedance sensor can avoid polarization effect and electrochemical erosion effect. The total impedance information is used and the void fraction measurement performance of the new sensor is satisfactory. The experimental results also indicate that the imaginary part of the impedance of gas-liquid two-phase flow is very useful for the void fraction measurement. Making full use of the total impedance information of gas-liquid two-phase flow can effectively improve the void fraction measurement

  6. High pressure hydrocracking of vacuum gas oil to middle distillates

    NASA Astrophysics Data System (ADS)

    Lahiri, C. R.; Biswas, Dipa

    1986-05-01

    Hydrocracking of heavier petroleum fractions into lighter ones is of increasing importance today to meet the huge demand, particularly for gasoline and middle distillates. Much work on hydrocracking of a gas oil range feed stock to mainly gasoline using modified zeolite catalyst-base exchanged with metals (namely Ni, Pd, Mo, etc.) has been reported. In India, however, present demand is for a maximum amount of middle distillate. The present investigation was therefore aimed to maximize the yield of middle distillate (140-270°C boiling range) by hydrocracking a vacuum gas oil (365-450°C boiling range) fraction from an Indian Refinery at high hydrogen pressure and temperature. A zeolite catalyst-base exchanged with 4.5% Ni was chosen for the reaction. A high pressure batch reactor with a rocking arrangement was used for the study. No pretreatment of the feed stock for sulphur removal applied as the total sulphur in the feed was less than 2%. The process variables studied for the maximum yield of the middle distillate were temperature 300-450°C, pressure 100-200 bar and residence period 1-3 h at the feed to catalyst ratio of 9.3 (wt/wt). The optimum conditions for the maximum yield of 36% middle distillate of the product were: temperature 400°C, pressure 34.5 bar (initially) and residence period 2 h. A carbon balance of 90-92% was found for each run.

  7. Absorption-line Spectroscopy of Gravitationally Lensed Galaxies: Further Constraints on the Escape Fraction of Ionizing Photons at High Redshift

    NASA Astrophysics Data System (ADS)

    Leethochawalit, Nicha; Jones, Tucker A.; Ellis, Richard S.; Stark, Daniel P.; Zitrin, Adi

    2016-11-01

    The fraction of ionizing photons escaping from high-redshift star-forming galaxies is a key obstacle in evaluating whether galaxies were the primary agents of cosmic reionization. We previously proposed using the covering fraction of low-ionization gas, measured via deep absorption-line spectroscopy, as a proxy. We now present a significant update, sampling seven gravitationally lensed sources at 4 < z < 5. We show that the absorbing gas in our sources is spatially inhomogeneous, with a median covering fraction of 66%. Correcting for reddening according to a dust-in-cloud model, this implies an estimated absolute escape fraction of ≃19% ± 6%. With possible biases and uncertainties, collectively we find that the average escape fraction could be reduced to no less than 11%, excluding the effect of spatial variations. For one of our lensed sources, we have sufficient signal-to-noise ratio to demonstrate the presence of such spatial variations and scatter in its dependence on the Lyα equivalent width, consistent with recent simulations. If this source is typical, our lower limit to the escape fraction could be reduced by a further factor ≃2. Across our sample, we find a modest anticorrelation between the inferred escape fraction and the local star formation rate, consistent with a time delay between a burst and leaking Lyman continuum photons. Our analysis demonstrates considerable variations in the escape fraction, consistent with being governed by the small-scale behavior of star-forming regions, whose activities fluctuate over short timescales. This supports the suggestion that the escape fraction may increase toward the reionization era when star formation becomes more energetic and burst-like.

  8. HALO GAS CROSS SECTIONS AND COVERING FRACTIONS OF Mg II ABSORPTION SELECTED GALAXIES

    SciTech Connect

    Kacprzak, Glenn G.; Churchill, Christopher W.; Steidel, Charles C.; Murphy, Michael T. E-mail: cwc@nmsu.edu E-mail: mmurphy@astro.swin.edu.au

    2008-03-15

    We examine halo gas cross sections and covering fractions, f{sub c} , of intermediate-redshift Mg II absorption selected galaxies. We computed statistical absorber halo radii, R{sub x}, using current values of dN/dz and Schechter luminosity function parameters, and have compared these values to the distribution of impact parameters and luminosities from a sample of 37 galaxies. For equivalent widths W{sub r}(2796) {>=} 0.3 A, we find 43 {<=} R{sub x} {<=} 88 kpc, depending on the lower luminosity cutoff and the slope, {beta}, of the Holmberg-like luminosity scaling, R {proportional_to} L{sup {beta}}. The observed distribution of impact parameters, D, are such that several absorbing galaxies lie at D>R{sub x} and several non-absorbing galaxies lie at D < R{sub x}. We deduced that f{sub c} must be less than unity and obtain a mean of {approx} 0.5 for our sample. Moreover, the data suggest that halo radii of Mg II absorbing galaxies do not follow a luminosity scaling with {beta} in the range of 0.2-0.28, if f{sub c} = 1 as previously reported. However, provided f{sub c} {approx} 0.5, we find that halo radii can remain consistent with a Holmberg-like luminosity relation with {beta} {approx_equal} 0.2 and R{sub *}= R{sub x}/{radical}(f{sub c}){approx}110 kpc. No luminosity scaling ({beta} = 0) is also consistent with the observed distribution of impact parameters if f{sub c} {<=} 0.37. The data support a scenario in which gaseous halos are patchy and likely have non-symmetric geometric distributions about the galaxies. We suggest that halo gas distributions may not be governed primarily by galaxy mass/luminosity but also by stochastic processes local to the galaxy.

  9. Supernova Feedback and the Hot Gas Filling Fraction of the Interstellar Medium

    NASA Astrophysics Data System (ADS)

    Li, Miao; Ostriker, Jeremiah P.; Cen, Renyue; Bryan, Greg L.; Naab, Thorsten

    2015-11-01

    Supernovae (SNe), the most energetic stellar feedback mechanism, are crucial for regulating the interstellar medium (ISM) and launching galactic winds. We explore how supernova remnants (SNRs) create a multiphase medium by performing three-dimentional hydrodynamical simulations at various SN rates, S, and ISM average densities, \\bar{n}. The evolution of an SNR in a self-consistently generated three-phase ISM is qualitatively different from that in a uniform or a two-phase warm/cold medium. By traveling faster and further in the low-density hot phase, the domain of an SNR increases by >102.5. Varying \\bar{n} and S, we find that a steady state can only be achieved when the hot gas volume fraction {f}{{V,hot}}≲ 0.6+/- 0.1. Above that level, overlapping SNRs render connecting topology of the hot gas, and the ISM is subjected to thermal runaway. Photoelectric heating (PEH) has a surprisingly strong impact on {f}{{V,hot}}. For \\bar{n}≳ 3 {{cm}}-3, a reasonable PEH rate is able to suppress the thermal runaway. Overall, we determine the critical SN rate for the onset of thermal runaway to be {S}{{crit}}=200{(\\bar{n}/1 {{cm}}-3)}k{({E}{{SN}}/{10}51 {{erg}})}-1 {{{kpc}}}-3 {{Myr}}-1, where k = (1.2, 2.7) for \\bar{n}≤slant 1 and \\gt 1 {{cm}}-3, respectively. We present a fitting formula of the ISM pressure P(\\bar{n},S), which can be used as an effective equation of state in cosmological simulations. Despite the five orders of magnitude span of (\\bar{n},S), the average Mach number varies little: {M} ≈ 0.5 ± 0.2, 1.2 ± 0.3, and 2.3 ± 0.9 for the hot, warm, and cold phases, respectively.

  10. A sub-grid, mixture-fraction-based thermodynamic equilibrium model for gas phase combustion in FIRETEC: development and results

    Treesearch

    M. M. Clark; T. H. Fletcher; R. R. Linn

    2010-01-01

    The chemical processes of gas phase combustion in wildland fires are complex and occur at length-scales that are not resolved in computational fluid dynamics (CFD) models of landscape-scale wildland fire. A new approach for modelling fire chemistry in HIGRAD/FIRETEC (a landscape-scale CFD wildfire model) applies a mixture– fraction model relying on thermodynamic...

  11. High resolution microprofiling, fractionation and speciation at sediment water interfaces

    NASA Astrophysics Data System (ADS)

    Fabricius, Anne-Lena; Duester, Lars; Ecker, Dennis; Ternes, Thomas A.

    2016-04-01

    Within aquatic environments, the exchange between the sediment and the overlaying water is often driven by steep gradients of, e.g., the oxygen concentration, the redox potential or the pH value at the sediment water interface (SWI). Important transport processes at the SWI are sedimentation and resuspension of particulate matter and diffusional fluxes of dissolved substances. To gain a better understanding of the key factors and processes determining the fate of substances at the SWI, methods with a spatial high resolution are required that enable the investigation of several sediment parameters in parallel to different analytes of interest in the sediment pore water. Moreover, beside the total content, questions concerning the speciation and fractionation are of concern in studying the different (transport) processes. Due to the availability of numerous micro-sensors and -electrodes (e.g., O2, redox potential, pH value, H2S, N2O) and the development of methods for pore water sampling [1], the toolbox to study the heterogeneous and often dynamic conditions at the SWI at a sub-millimetre scale were considerably improved. Nevertheless, the methods available for pore water sampling often require the installation of the sampling devices at the sampling site and/or intensive preparation procedures that may influence the conditions at the area studied and/or the characteristics of the samples taken. By combination of a micro profiling system with a new micro filtration probe head connected to a pump and a fraction collector, a micro profiling and micro sampling system ("missy") was developed that enables for the first time a direct, automate and low invasive sampling of small volumes (<500 μL) at a spatial high resolution of a few millimetres to sub-millimetres [2]. Via the application of different sample preparation procedures followed by inductively plasma-mass spectrometry analyses, it was possible to address not only the total content of metal(loid)s, but also

  12. A New Void Fraction Measurement Method for Gas-Liquid Two-Phase Flow in Small Channels

    PubMed Central

    Li, Huajun; Ji, Haifeng; Huang, Zhiyao; Wang, Baoliang; Li, Haiqing; Wu, Guohua

    2016-01-01

    Based on a laser diode, a 12 × 6 photodiode array sensor, and machine learning techniques, a new void fraction measurement method for gas-liquid two-phase flow in small channels is proposed. To overcome the influence of flow pattern on the void fraction measurement, the flow pattern of the two-phase flow is firstly identified by Fisher Discriminant Analysis (FDA). Then, according to the identification result, a relevant void fraction measurement model which is developed by Support Vector Machine (SVM) is selected to implement the void fraction measurement. A void fraction measurement system for the two-phase flow is developed and experiments are carried out in four different small channels. Four typical flow patterns (including bubble flow, slug flow, stratified flow and annular flow) are investigated. The experimental results show that the development of the measurement system is successful. The proposed void fraction measurement method is effective and the void fraction measurement accuracy is satisfactory. Compared with the conventional laser measurement systems using standard laser sources, the developed measurement system has the advantages of low cost and simple structure. Compared with the conventional void fraction measurement methods, the proposed method overcomes the influence of flow pattern on the void fraction measurement. This work also provides a good example of using low-cost laser diode as a competent replacement of the expensive standard laser source and hence implementing the parameter measurement of gas-liquid two-phase flow. The research results can be a useful reference for other researchers’ works. PMID:26828488

  13. Effect of Fuel Fraction on Small Modified CANDLE Burn-up Based Gas Cooled Fast Reactors

    SciTech Connect

    Ariani, Menik; Su'ud, Zaki; Waris, Abdul; Asiah, Nur; Shafii, M. Ali; Khairurrijal

    2010-12-23

    A conceptual design study of Gas Cooled Fast Reactors with Modified CANDLE Burn-up has been performed. The objective of this research is to get optimal design parameters of such type reactors. The parameters of nuclear design including the critical condition, conversion ratio, and burn-up level were compared. These parameters are calculated by variation in the fuel fraction 47.5% up to 70%. Two dimensional full core multi groups diffusion calculations was performed by CITATION code. Group constant preparations are performed by using SRAC code system with JENDL-3.2 nuclear data library. In this design the reactor cores with cylindrical cell two dimensional R-Z core models are subdivided into several parts with the same volume in the axial directions. The placement of fuel in core arranged so that the result of plutonium from natural uranium can be utilized optimally for 10 years reactor operation. Modified CANDLE burn-up was established successfully in a core radial width 1.4 m. Total thermal power output for reference core is 550 MW. Study on the effect of fuel to coolant ratio shows that effective multiplication factor (k{sub eff}) is in almost linear relations with the change of the fuel volume to coolant ratio.

  14. The effect of pH and gas composition on the bubble fractionation of proteins

    SciTech Connect

    DeSouza, A.H.G.; Tanner, R.D.; Effler, W.T. Jr.

    1991-12-31

    Studies were conducted to establish the effect of the variation of environmental factors on the separation occurring in protein systems, resulting from bubble fractionation in a bioreactor. The measure of separation was selected to be the separation ratio. This is defined to be the ratio of either the top or the middle position concentration in the vessel to the bottom concentration of the vessel. Invertase and Ce-amylase were the two {open_quotes}model{close_quotes} enzymes considered. It was observed that, under certain conditions, i.e., a combination of the nature of the sparging gas and the medium pH, varying degrees of protein separation were achieved. The pH of the system dramatically influenced the separation. It was found that the best separation occurred at a certain pH, assumed to be at or close to the pI of the protein in question. Furthermore, it was observed that systems sparged with CO{sub 2} exhibited greater separation than systems sparged with air. In fact, in the case of invertase, almost threefold separation was observed at the top port when the solution was sparged with CO{sub 2}.

  15. Effect of Fuel Fraction on Small Modified CANDLE Burn-up Based Gas Cooled Fast Reactors

    NASA Astrophysics Data System (ADS)

    Ariani, Menik; Su'ud, Zaki; Waris, Abdul; Khairurrijal, Asiah, Nur; Shafii, M. Ali

    2010-12-01

    A conceptual design study of Gas Cooled Fast Reactors with Modified CANDLE Burn-up has been performed. The objective of this research is to get optimal design parameters of such type reactors. The parameters of nuclear design including the critical condition, conversion ratio, and burn-up level were compared. These parameters are calculated by variation in the fuel fraction 47.5% up to 70%. Two dimensional full core multi groups diffusion calculations was performed by CITATION code. Group constant preparations are performed by using SRAC code system with JENDL-3.2 nuclear data library. In this design the reactor cores with cylindrical cell two dimensional R-Z core models are subdivided into several parts with the same volume in the axial directions. The placement of fuel in core arranged so that the result of plutonium from natural uranium can be utilized optimally for 10 years reactor operation. Modified CANDLE burn-up was established successfully in a core radial width 1.4 m. Total thermal power output for reference core is 550 MW. Study on the effect of fuel to coolant ratio shows that effective multiplication factor (keff) is in almost linear relations with the change of the fuel volume to coolant ratio.

  16. Coarsening in high volume fraction nickel-base alloys

    NASA Technical Reports Server (NTRS)

    Mackay, R. A.; Nathal, M. V.

    1990-01-01

    The coarsening behavior of the gamma-prime precipitate has been examined in high volume fraction nickel-base alloys aged at elevated temperatures for times of up to 5000 h. Although the cube rate law was observed during coarsening, none of the presently available coarsening theories showed complete agreement with the experimental particle size distributions (PSDs). These discrepancies were thought to be due to elastic coherency strains which were not considered by the available models. Increasing the Mo content significantly influenced the PSDs and decreased the coarsening rate of the gamma-prime cubes, as a result of increasing the magnitude of the lattice mismatch. After extended aging times, the gamma-prime cubes underwent massive coalescence into plates at a rate which was much faster than the cuboidal coarsening rate. Once the gamma-prime plates were formed, further coarsening was not observed, and this stabilization of the microstructure was attributed to the development of dislocation networks at the gamma-gamma-prime interfaces.

  17. Fractionating Polymer Microspheres as Highly Accurate Density Standards.

    PubMed

    Bloxham, William H; Hennek, Jonathan W; Kumar, Ashok A; Whitesides, George M

    2015-07-21

    This paper describes a method of isolating small, highly accurate density-standard beads and characterizing their densities using accurate and experimentally traceable techniques. Density standards have a variety of applications, including the characterization of density gradients, which are used to separate objects in a variety of fields. Glass density-standard beads can be very accurate (±0.0001 g cm(-3)) but are too large (3-7 mm in diameter) for many applications. When smaller density standards are needed, commercial polymer microspheres are often used. These microspheres have standard deviations in density ranging from 0.006 to 0.021 g cm(-3); these distributions in density make these microspheres impractical for applications demanding small steps in density. In this paper, commercial microspheres are fractionated using aqueous multiphase systems (AMPS), aqueous mixture of polymers and salts that spontaneously separate into phases having molecularly sharp steps in density, to isolate microspheres having much narrower distributions in density (standard deviations from 0.0003 to 0.0008 g cm(-3)) than the original microspheres. By reducing the heterogeneity in densities, this method reduces the uncertainty in the density of any specific bead and, therefore, improves the accuracy within the limits of the calibration standards used to characterize the distributions in density.

  18. High Energy Vibration for Gas Piping

    NASA Astrophysics Data System (ADS)

    Lee, Gary Y. H.; Chan, K. B.; Lee, Aylwin Y. S.; Jia, ShengXiang

    2017-07-01

    In September 2016, a gas compressor in offshore Sarawak has its rotor changed out. Prior to this change-out, pipe vibration study was carried-out by the project team to evaluate any potential high energy pipe vibration problems at the compressor’s existing relief valve downstream pipes due to process condition changes after rotor change out. This paper covers high frequency acoustic excitation (HFAE) vibration also known as acoustic induced vibration (AIV) study and discusses detailed methodologies as a companion to the Energy Institute Guidelines for the avoidance of vibration induced fatigue failure, which is a common industry practice to assess and mitigate for AIV induced fatigue failure. Such detailed theoretical studies can help to minimize or totally avoid physical pipe modification, leading to reduce offshore plant shutdown days to plant shutdowns only being required to accommodate gas compressor upgrades, reducing cost without compromising process safety.

  19. High pressure synthesis gas conversion. Final report

    SciTech Connect

    Not Available

    1993-05-01

    The purpose of this research project is to build and test a high pressure fermentation system for the production of ethanol from synthesis gas. The fermenters, pumps, controls, and analytical system were procured or fabricated and assembled in our laboratory. This system was then used to determine the effects of high pressure on growth and ethanol production by Clostridium ljungdahlii. The limits of cell concentration and mass transport relationships were found in CSTR and immobilized cell reactors (ICR). The minimum retention times and reactor volumes were found for ethanol production in these reactors. A maximum operating pressure of 150 psig has been shown to be possible for C. ljungdahlli with the medium of Phillips et al. This medium was developed for atmospheric pressure operation in the CSTR to yield maximum ethanol concentrations and thus is not best for operation at elevated pressures. It is recommended that a medium development study be performed for C. ljungdahlii at increased pressure. Cell concentration, gas conversion and product concentration profiles were presented for C. ljungdahlii as a function of gas flow rate, the variable which affects bacterium performance the most. This pressure was chosen as a representative pressure over the 0--150 psig operating pressure range for the bacterium. Increased pressure negatively affected ethanol productivity probably due to the fact that medium composition was designed for atmospheric pressure operation. Medium development at increased pressure is necessary for high pressure development of the system.

  20. High-Field Fractional Quantum Hall Effect in Optical Lattices

    SciTech Connect

    Palmer, R.N.; Jaksch, D.

    2006-05-12

    We consider interacting bosonic atoms in an optical lattice subject to a large simulated magnetic field. We develop a model similar to a bilayer fractional quantum Hall system valid near simple rational numbers of magnetic flux quanta per lattice cell. Then we calculate its ground state, magnetic lengths, fractional fillings, and find unexpected sign changes in the Hall current. Finally we study methods for detecting these novel features via shot noise and Hall current measurements.

  1. An experimental study of on-line measurement of water fraction in gas-oil-water three-phase flow

    NASA Astrophysics Data System (ADS)

    Chen, K.; Guo, L. J.; Ye, J.

    2012-03-01

    Gas-oil-water two-or three-phase flow is widely encountered in industry, such as petroleum chemical industry, bio-chemicals, food chemicals, and mineral engineering and energy projects. Two kinds of on-line measurement technique, which are double-ring conductance sensor and double-helical capacitance sensor, for water fraction in oil-water two-phase flow and gas-oil-water three-phase flow were developed in this paper. The calibration results shows that the responses of the two sensors are good enough as the variation of water fraction. And on the other hand, it is possible that the oil and the gas regard as one phase in gas-oil-water three-phase flow by using double-helical capacitance sensor, and the ratio between water and gas has no effect with the output signal. The range of water fraction which can be measured becomes bigger and bigger because of the using of new circuit. So the capacitance sensor is better enough to measure water fraction in the three phases flow. During dynamic experiment, because of phase inversion phenomenon between oil and water, the conductance sensor outputs poorly, however the capacitance sensor performs somewhat fine. The reason for the error using capacitance sensor is the edge effect of the capacitance. The experiment results show that the edge effect of the double-helical capacitance sensor causes that the output is smaller so that the measuring water fraction is a litter larger than the actual value. And when the variation of water fraction is above 10%, the edge effect of capacitance sensor can be almost neglected. On the contrary, when the variation of water fraction is below 10%, the edge effect is so lager than the results above that it cannot be ignored. Consequently, the double-helical capacitance probe is more suitable for measuring water fraction in slug flow and oil-water emulsion, in which the results agree better with static calibration than that in bubble flow.

  2. Highly ionized atoms in cooling gas

    NASA Technical Reports Server (NTRS)

    Edgar, R. J.; Chevalier, R. A.

    1986-01-01

    The ionization of low density gas cooling from a high temperature was calculated. The evolution during the cooling is assumed to be isochoric, isobaric, or a combination of these cases. The calculations are used to predict the column densities and ultraviolet line luminosities of highly ionized atoms in cooling gas. In a model for cooling of a hot galactic corona, it is shown that the observed value of N(N V) can be produced in the cooling gas, while the predicted value of N(Si IV) falls short of the observed value by a factor of about 5. The same model predicts fluxes of ultraviolet emission lines that are a factor of 10 lower than the claimed detections of Feldman, Brune, and Henry. Predictions are made for ultraviolet lines in cooling flows in early-type galaxies and clusters of galaxies. It is shown that the column densities of interest vary over a fairly narrow range, while the emission line luminosities are simply proportional to the mass inflow rate.

  3. Characterization of novel single-variety oxygenated sesquiterpenoid hop oil fractions via headspace solid-phase microextraction and gas chromatography-mass spectrometry/olfactometry.

    PubMed

    Van Opstaele, Filip; Praet, Tatiana; Aerts, Guido; De Cooman, Luc

    2013-11-06

    The volatile composition of novel varietal oxygenated sesquiterpenoid hop oil fractions ("spicy essences") was characterized by headspace solid-phase microextraction in combination with gas chromatography-mass spectrometry. Oxygenated sesquiterpenes represent the major chemical compound class, accounting for at least 65% of the total volatile fraction. In addition to oxygenated sesquiterpenes, spicy hop essences consist of several ketones, sesquiterpene and monoterpene hydrocarbons, and a relatively high number of unidentified compounds. On the basis of their relative composition, spicy hop essences can be fully differentiated according to their varietal origin. Multidimensional gas chromatography in combination with time-of-flight mass spectrometry on spicy hop essence cv. Spalter Select further demonstrated the enormous complexity of this particular hop oil fraction. The aromagram obtained via gas chromatography-olfactometry comprised nine odor-active regions described in terms of "citrus", "green", "haylike", "earthy", "woody", and "spicy". 2-Undecanone, 2-tridecanone, γ-cadinene, α-calacorene, calarene, humuladienone, caryolan-1-ol, caryophyllene oxide enantiomers, and humulene epoxide II are tentatively identified in the odor-active zones.

  4. An experimental study of the size effect on adiabatic gas-liquid two-phase flow patterns and void fraction in microchannels

    NASA Astrophysics Data System (ADS)

    Xiong, Renqiang; Chung, J. N.

    2007-03-01

    Adiabatic gas-liquid flow patterns and void fractions in microchannels were experimentally investigated. Using nitrogen and water, experiments were conducted in rectangular microchannels with hydraulic diameters of 0.209mm, 0.412mm and 0.622mm, respectively. Gas and liquid superficial velocities were varied from 0.06-72.3m/s and 0.02-7.13m/s, respectively. The main objective is focused on the effects of microscale channel sizes on the flow regime map and void fraction. The instability of flow patterns was observed. Four groups of flow patterns including bubbly slug flow, slug-ring flow, dispersed-churn flow, and annular flow were observed in microchannels of 0.412mm and, 0.622mm. In the microchannel of 0.209mm, the bubbly slug flow became the slug flow and the dispersed-churn flow disappeared. The current flow regime maps showed the transition lines shifted to higher gas superficial velocity due to a dominant surface tension effect as the channel size was reduced. The regime maps presented by other authors for minichannels were found to not be applicable for microchannels. Time-averaged void fractions were measured by analyzing 8000 high speed video images for each flow condition. The void fractions hold a nonlinear relationship with the homogeneous void fraction as opposed to the relatively linear trend for the minichannels. A new correlation was developed to predict the nonlinear relationship that fits most of the current experimental data and those of the 0.1mm diameter tube reported by Kawahara et al. [Int. J. Multiphase Flow 28, 1411 (2002)] within ±15%.

  5. Oscillation spectrum of an electron gas with a small density fraction of ions

    SciTech Connect

    Yeliseyev, Yu. N.

    2010-07-15

    The problem is solved of the stability of a nonneutral plasma that completely fills a waveguide and consists of magnetized cold electrons and a small density fraction of ions produced by ionization of the atoms of the background gas. The ions are described by an anisotropic distribution function that takes into account the characteristic features of their production in crossed electric and magnetic fields. By solving a set of Vlasov-Poisson equations analytically, a dispersion equation is obtained that is valid over the entire range of allowable electric and magnetic field strengths. The solutions to the dispersion equation for the m = +1 main azimuthal mode are found numerically. The plasma oscillation spectrum consists of the families of Trivelpiece-Gould modes at frequencies equal to the frequencies of oblique Langmuir oscillations Doppler shifted by the electron rotation and also of the families of 'modified' ion cyclotron (MIC) modes at frequencies close to the harmonics of the MIC frequency (the frequencies of radial ion oscillations in crossed fields). It is shown that, over a wide range of electric and magnetic field strengths, Trivelpiece-Gould modes have low frequencies and interact with MIC modes. Trivelpiece-Gould modes at frequencies close to the harmonics of the MIC frequency with nonnegative numbers are unstable. The lowest radial Trivelpiece-Gould mode at a frequency close to the zeroth harmonic of the MIC frequency has the fastest growth rate. MIC modes are unstable over a wide range of electric and magnetic field strengths and grow at far slower rates. For a low ion density, a simplified dispersion equation is derived perturbatively that accounts for the nonlocal ion contribution, but, at the same time, has the form of a local dispersion equation for a plasma with a transverse current and anisotropic ions. The solutions to the simplified dispersion equation are obtained analytically. The growth rates of the Trivelpiece-Gould modes and the behavior

  6. Magnetically Regulated Gas Accretion in High-Redshift Galactic Disks

    NASA Astrophysics Data System (ADS)

    Birnboim, Yuval

    2009-09-01

    Disk galaxies are in hydrostatic equilibrium along their vertical axis. The pressure allowing for this configuration consists of thermal, turbulent, magnetic, and cosmic-ray components. For the Milky Way the thermal pressure contributes ~10% of the total pressure near the plane, with this fraction dropping toward higher altitudes. Out of the rest, magnetic fields contribute ~1/3 of the pressure to distances of ~3 kpc above the disk plane. In this Letter, we attempt to extrapolate these local values to high-redshift, rapidly accreting, rapidly star-forming disk galaxies and study the effect of the extra pressure sources on the accretion of gas onto the galaxies. In particular, magnetic field tension may convert a smooth cold-flow accretion to clumpy, irregular star formation regions and rates. The infalling gas accumulates on the edge of the magnetic fields, supported by magnetic tension. When the mass of the infalling gas exceeds some threshold mass, its gravitational force cannot be balanced by magnetic tension anymore, and it falls toward the disk's plane, rapidly making stars. Simplified estimations of this threshold mass are consistent with clumpy star formation observed in SINS, UDF, GOODS, and GEMS surveys. We discuss the shortcomings of pure hydrodynamic codes in simulating the accretion of cold flows into galaxies, and emphasize the need for magnetohydrodynamic simulations.

  7. High performance hand-held gas chromatograph

    SciTech Connect

    Yu, C.M.

    1998-04-28

    The Microtechnology Center of Lawrence Livermore National Laboratory has developed a high performance hand-held, real time detection gas chromatograph (HHGC) by Micro-Electro-Mechanical-System (MEMS) technology. The total weight of this hand-held gas chromatograph is about five lbs., with a physical size of 8{close_quotes} x 5{close_quotes} x 3{close_quotes} including carrier gas and battery. It consumes about 12 watts of electrical power with a response time on the order of one to two minutes. This HHGC has an average effective theoretical plate of about 40k. Presently, its sensitivity is limited by its thermal sensitive detector at PPM. Like a conventional G.C., this HHGC consists mainly of three major components: (1) the sample injector, (2) the column, and (3) the detector with related electronics. The present HHGC injector is a modified version of the conventional injector. Its separation column is fabricated completely on silicon wafers by means of MEMS technology. This separation column has a circular cross section with a diameter of 100 pm. The detector developed for this hand-held GC is a thermal conductivity detector fabricated on a silicon nitride window by MEMS technology. A normal Wheatstone bridge is used. The signal is fed into a PC and displayed through LabView software.

  8. Induced superconductivity in high-mobility two-dimensional electron gas in gallium arsenide heterostructures

    PubMed Central

    Wan, Zhong; Kazakov, Aleksandr; Manfra, Michael J.; Pfeiffer, Loren N.; West, Ken W.; Rokhinson, Leonid P.

    2015-01-01

    Search for Majorana fermions renewed interest in semiconductor–superconductor interfaces, while a quest for higher-order non-Abelian excitations demands formation of superconducting contacts to materials with fractionalized excitations, such as a two-dimensional electron gas in a fractional quantum Hall regime. Here we report induced superconductivity in high-mobility two-dimensional electron gas in gallium arsenide heterostructures and development of highly transparent semiconductor–superconductor ohmic contacts. Supercurrent with characteristic temperature dependence of a ballistic junction has been observed across 0.6 μm, a regime previously achieved only in point contacts but essential to the formation of well separated non-Abelian states. High critical fields (>16 T) in NbN contacts enables investigation of an interplay between superconductivity and strongly correlated states in a two-dimensional electron gas at high magnetic fields. PMID:26067452

  9. Induced superconductivity in high-mobility two-dimensional electron gas in gallium arsenide heterostructures.

    PubMed

    Wan, Zhong; Kazakov, Aleksandr; Manfra, Michael J; Pfeiffer, Loren N; West, Ken W; Rokhinson, Leonid P

    2015-06-11

    Search for Majorana fermions renewed interest in semiconductor-superconductor interfaces, while a quest for higher-order non-Abelian excitations demands formation of superconducting contacts to materials with fractionalized excitations, such as a two-dimensional electron gas in a fractional quantum Hall regime. Here we report induced superconductivity in high-mobility two-dimensional electron gas in gallium arsenide heterostructures and development of highly transparent semiconductor-superconductor ohmic contacts. Supercurrent with characteristic temperature dependence of a ballistic junction has been observed across 0.6 μm, a regime previously achieved only in point contacts but essential to the formation of well separated non-Abelian states. High critical fields (>16 T) in NbN contacts enables investigation of an interplay between superconductivity and strongly correlated states in a two-dimensional electron gas at high magnetic fields.

  10. Recycle and fractionation of U and K in the mantle via slab subduction; noble gas isotopic evidence from Polynesian HIMU

    NASA Astrophysics Data System (ADS)

    Hanyu, Takeshi; Tatsumi, Yoshiyuki; Kimura, Jun-Ichi

    2013-04-01

    The abundance and distribution of U and K in the Earth are critical not only for isotope and noble gas geochemistry but also for internal heat production in the mantle. While the concentration of U in bulk silicate Earth (BSE) has been estimated from the chondritic value, K concentration in BSE is poorly constrained. K concentration in BSE has been estimated using U concentration in BSE multiplied by the canonical K/U ratio (13000) on the ground that crustal and mantle-derived rocks show uniform K/U. However, such theory might be uncertain if the subducted slab had fractionated K/U and it remained isolated as a hidden reservoir. We present He-Ne-Ar isotopic compositions for Polynesian HIMU lavas with radiogenic Pb isotopic compositions. It has been widely accepted that the HIMU lavas are sourced from subducted ancient oceanic crust. K/U of the HIMU reservoir is constrained using the relative abundances of radiogenic and nucleogenic noble gases, because 40Ar/36Ar evolves by decay of 40K while production of 4He and 21Ne is related with U and Th decay. In 4He/40Ar*-4He/21Ne* space (asterisks denote radiogenic component), the HIMU lavas define a trend that is parallel to, but offset from the trend previously observed for other ocean island basalts. Using 4He/21Ne* as a monitor of elemental fractionation of noble gasses, fractionation-corrected 4He/40Ar* is higher than that expected for the mantle with the canonical K/U of 13000. K/U of the HIMU reservoir converted from 4He/40Ar* is approximately 3000. Low K/U of the HIMU reservoir is best explained by a model where this reservoir originates from subducted oceanic crust that preferentially lost K relative to U via dehydration during its subduction. Since the HIMU reservoir, involving subducted oceanic crust, is enriched in U, but not in K, previous estimates of K/U and K concentrations for BSE, that did not take this reservoir into consideration, will be too high. The mass balance calculation, considering continental

  11. Magma Dynamics at Mid-Ocean Ridges by Noble Gas Kinetic Fractionation: Assessment of Magmatic Ascent Rates and Mantle Composition

    NASA Astrophysics Data System (ADS)

    Paonita, A.; Martelli, M.

    2007-12-01

    Topical scientific literature on magma degassing at mid-ocean ridges more and more focuses on exsolution processes occurring under conditions that are far from thermodynamic equilibrium between bubbles and silicate melt. Indeed, the dynamics of magma ascent and decompression can be faster than that of CO2 diffusion into bubbles, in which case the diffusivity ratios among volatiles are the main control of the composition of the exsolving gas phase. We have developed a model of bubble growth in silicate melts that calculates the extent of both CO2 supersaturation and kinetic fractionation among noble gases in vesicles in relation to the decompressive rate of basaltic melts. The model predicts that, due to comparable Ar and CO2 diffusivity, magma degassing at low pressure fractionates both He/Ar and He/CO2 ratios by a similar extent, while the slower CO2 diffusion at high pressure causes early kinetic effects on Ar/CO2 ratio and dramatically changes the degassing paths. By using this tool, we have reviewed the global He-Ar-CO2 dataset of fluid inclusions in mid-ocean-ridge glasses. We display that non-equilibrium fractionations among He, Ar and CO2, driven by their different diffusivities in silicate melts, are common in most of the natural conditions of magma decompression and their signature strongly depends on pressure of degassing. The different geochemical signatures among suites of data coming from different ridge segments mainly depend on the depth of the magma chamber where the melt was stored. Moreover, variations inside a single suite emerge due to the interplay between variable ascent speed of magma and cooling rate of the emplaced lava. As a result, two data groups coming from the Pito Seamount suite (Easter Microplate East ridge), showing different degree of CO2 supersaturation and He/Ar fractionation, provide ascent rates which differ by ten folds or even more. The large variations in both the He/CO2 and Ar/CO2 ratios at almost constant He/Ar, displayed

  12. High temperature surface protection. [10 gas turbines

    NASA Technical Reports Server (NTRS)

    Levine, S. R.

    1978-01-01

    Alloys of the MCrAlX type are the basis for high temperature surface protection systems in gas turbines. M can be one or more of Ni, Co, or Fe and X denotes a reactive metal added to enhance oxide scale adherence. The selection and formation as well as the oxidation, hot corrosion and thermal fatigue performance of MCrAlX coatings are discussed. Coatings covered range from simple aluminides formed by pack cementation to the more advanced physical vapor deposition overlay coatings and developmental plasma spray deposited thermal barrier coatings.

  13. Continuous fraction collection of gas chromatographic separations with parallel mass spectrometric detection applied to cell-based bioactivity analysis.

    PubMed

    Jonker, Willem; Stöckl, Jan B; de Koning, Sjaak; Schaap, Jaap; Somsen, Govert W; Kool, Jeroen

    2017-06-01

    We describe the development and evaluation of a GC-MS fractionation platform that combines high-resolution fraction collection of full chromatograms with parallel MS detection. A y-split at the column divides the effluent towards the MS detector and towards an inverted y-piece where vaporized trap solvent is infused. The latter flow is directed outside the GC oven allowing subsequent condensation and stepwise collection of liquid fractions with trapped analytes on a 384-well plate. For study and optimization of the effluent split ratio, restriction capillaries of different lengths and diameters were evaluated. For a wide range of settings, local pressures were monitored during fractionation to assess the influence of MS vacuum and trap solvent infusion on the GC system stability. The platform performance was evaluated by GC-MS analysis and continuous fractionation of an n-alkane mixture followed by GC analysis of each fraction. Comparison of the on-line recorded and fraction-reconstructed chromatogram showed the GC separation is maintained during fractionation. Multiple fractionation cycles of the n-alkane sample on the same 384-well plate yielded a reconstructed chromatogram which was highly similar to that of a single analysis, demonstrating the high repeatability. The applicability of the GC-MS-fractionation platform for bioactivity screening was investigated by applying the AR-Ecoscreen reporter gene bioassay on fractions obtained after analysis of standard solutions and dust samples containing the anti-androgenic compounds vinclozolin and p,p'-DDE. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. The KMOS Redshift One Spectroscopic Survey (KROSS): dynamical properties, gas and dark matter fractions of typical z ˜ 1 star-forming galaxies

    NASA Astrophysics Data System (ADS)

    Stott, John P.; Swinbank, A. M.; Johnson, Helen L.; Tiley, Alfie; Magdis, Georgios; Bower, Richard; Bunker, Andrew J.; Bureau, Martin; Harrison, Chris M.; Jarvis, Matt J.; Sharples, Ray; Smail, Ian; Sobral, David; Best, Philip; Cirasuolo, Michele

    2016-04-01

    The KMOS Redshift One Spectroscopic Survey (KROSS) is an ESO-guaranteed time survey of 795 typical star-forming galaxies in the redshift range z = 0.8-1.0 with the KMOS instrument on the Very Large Telescope. In this paper, we present resolved kinematics and star formation rates for 584 z ˜ 1 galaxies. This constitutes the largest near-infrared Integral Field Unit survey of galaxies at z ˜ 1 to date. We demonstrate the success of our selection criteria with 90 per cent of our targets found to be H α emitters, of which 81 per cent are spatially resolved. The fraction of the resolved KROSS sample with dynamics dominated by ordered rotation is found to be 83 ± 5 per cent. However, when compared with local samples these are turbulent discs with high gas to baryonic mass fractions, ˜35 per cent, and the majority are consistent with being marginally unstable (Toomre Q ˜ 1). There is no strong correlation between galaxy averaged velocity dispersion and the total star formation rate, suggesting that feedback from star formation is not the origin of the elevated turbulence. We postulate that it is the ubiquity of high (likely molecular) gas fractions and the associated gravitational instabilities that drive the elevated star formation rates in these typical z ˜ 1 galaxies, leading to the 10-fold enhanced star formation rate density. Finally, by comparing the gas masses obtained from inverting the star formation law with the dynamical and stellar masses, we infer an average dark matter to total mass fraction within 2.2re (9.5 kpc) of 65 ± 12 per cent, in agreement with the results from hydrodynamic simulations of galaxy formation.

  15. A control system for maintaining high stability in gas pressure

    SciTech Connect

    Wuest, C.R.; Hendricks, C.D.

    1987-09-01

    A pressure control system has been implemented on an experiment designed to detect the presence of fractional charges in bulk matter. The experiment utilizes a liquid-droplet generation technique requiring high-stability gas-pressure delivery to ensure accurate data collection. The pressure control system consists of a pressurized mercury reservoir containing a low-vapor-pressure, diffusion-pump oil. A commercially available differential pressure transducer, servo-driven valve, and controller sense the pressure fluctuations with respect to a static reference pressure. The system can maintain constant pressure to better than one part in 10,000 at working pressures in the range of 100 to 300 psi. 3 refs., 7 figs.

  16. Effects of dry bulk density and particle size fraction on gas transport parameters in variably saturated landfill cover soil.

    PubMed

    Wickramarachchi, Praneeth; Kawamoto, Ken; Hamamoto, Shoichiro; Nagamori, Masanao; Moldrup, Per; Komatsu, Toshiko

    2011-12-01

    Landfill sites are emerging in climate change scenarios as a significant source of greenhouse gases. The compacted final soil cover at landfill sites plays a vital role for the emission, fate and transport of landfill gases. This study investigated the effects of dry bulk density, ρ(b), and particle size fraction on the main soil-gas transport parameters - soil-gas diffusivity (D(p)/D(o), ratio of gas diffusion coefficients in soil and free air) and air permeability (k(a)) - under variably-saturated moisture conditions. Soil samples were prepared by three different compaction methods (Standard and Modified Proctor compaction, and hand compaction) with resulting ρ(b) values ranging from 1.40 to 2.10 g cm(-3). Results showed that D(p) and k(a) values for the '+gravel' fraction (<35 mm) became larger than for the '-gravel' fraction (<2mm) under variably-saturated conditions for a given soil-air content (ε), likely due to enhanced gas diffusion and advection through less tortuous, large-pore networks. The effect of dry bulk density on D(p) and k(a) was most pronounced for the '+gravel' fraction. Normalized ratios were introduced for all soil-gas parameters: (i) for gas diffusivity D(p)/D(f), the ratio of measured D(p) to D(p) in total porosity (f), (ii) for air permeability k(a)/k(a)(,pF4.1), the ratio of measured k(a) to k(a) at 1235 kPa matric potential (=pF 4.1), and (iii) for soil-air content, the ratio of soil-air content (ε) to total porosity (f) (air saturation). Based on the normalized parameters, predictive power-law models for D(p)(ε/f) and k(a)(ε/f) models were developed based on a single parameter (water blockage factor M for D(p) and P for k(a)). The water blockage factors, M and P, were found to be linearly correlated to ρ(b) values, and the effects of dry bulk density on D(p) and k(a) for both '+gravel' and '-gravel' fractions were well accounted for by the new models.

  17. Picosecond High Pressure Gas Switch experiment

    SciTech Connect

    Cravey, W.R.; Freytag, E.K.; Goerz, D.A.; Poulsen, P.; Pincosy, P.A.

    1993-08-01

    A high Pressure Gas Switch has been developed and tested at LLNL. Risetimes on the order of 200 picoseconds have been observed at 1 kHz prf and 1 atmosphere pressures. Calculations show that switching closure times on the order of tens of picoseconds can be achieved at higher pressures and electric fields. A voltage hold-off of 1 MV/cm has been measured at 10 atmospheres and several MV/cm appears possible with the HPGS. With such high electric field levels, energy storage of tens of Joules in a reasonably sized package is achievable. Initial HPGS performance has been characterized using the WASP pulse generator at LLNL. A detailed description of the switch used for initial testing is given. Switch recovery times of 1-ms have been measured at 1 atmosphere. Data on the switching uniformity, voltage hold-off recovery, and pulse repeatability, is presented. In addition, a physics switch model is described and results are compared with experimental data. Modifications made to the WASP HV pulser in order to drive the HPGS will also be discussed. Recovery times of less than 1 ms were recorded without gas flow in the switch chambers. Low pressure synthetic air was used as the switch dielectric. Longer recovery times were required when it was necessary to over-voltage the switch.

  18. High speed exhaust gas recirculation valve

    SciTech Connect

    Fensom, Rod; Kidder, David J.

    2005-01-18

    In order to minimize pollutants such as Nox, internal combustion engines typically include an exhaust gas recirculation (EGR) valve that can be used to redirect a portion of exhaust gases to an intake conduit, such as an intake manifold, so that the redirected exhaust gases will be recycled. It is desirable to have an EGR valve with fast-acting capabilities, and it is also desirable to have the EGR valve take up as little space as possible. An exhaust gas recirculation valve is provided that includes an exhaust passage tube, a valve element pivotally mounted within the exhaust passage tube, a linear actuator; and a gear train. The gear train includes a rack gear operatively connected to the linear actuator, and at least one rotatable gear meshing with the rack gear and operatively connected to the valve element to cause rotation of the valve element upon actuation of the linear actuator. The apparatus provides a highly compact package having a high-speed valve actuation capability.

  19. Development of High Temperature Gas Sensor Technology

    NASA Technical Reports Server (NTRS)

    Hunter, Gary W.; Chen, Liang-Yu; Neudeck, Philip G.; Knight, Dak; Liu, Chung-Chiun; Wu, Quing-Hai; Zhou, Huan-Jun

    1997-01-01

    The measurement of engine emissions is important for their monitoring and control. However, the ability to measure these emissions in-situ is limited. We are developing a family of high temperature gas sensors which are intended to operate in harsh environments such as those in an engine. The development of these sensors is based on progress in two types of technology: (1) The development of SiC-based semiconductor technology; and (2) Improvements in micromachining and microfabrication technology. These technologies are being used to develop point-contact sensors to measure gases which are important in emission control especially hydrogen, hydrocarbons, nitrogen oxides, and oxygen. The purpose of this paper is to discuss the development of this point-contact sensor technology. The detection of each type of gas involves its own challenges in the fields of materials science and fabrication technology. Of particular importance is sensor sensitivity, selectivity, and stability in long-term, high temperature operation. An overview is presented of each sensor type with an evaluation of its stage of development. It is concluded that this technology has significant potential for use in engine applications but further development is necessary.

  20. Sounding experiments of high pressure gas discharge

    SciTech Connect

    Biele, Joachim K.

    1998-07-10

    A high pressure discharge experiment (200 MPa, 5{center_dot}10{sup 21} molecules/cm{sup 3}, 3000 K) has been set up to study electrically induced shock waves. The apparatus consists of the combustion chamber (4.2 cm{sup 3}) to produce high pressure gas by burning solid propellant grains to fill the electrical pump chamber (2.5 cm{sup 3}) containing an insulated coaxial electrode. Electrical pump energy up to 7.8 kJ at 10 kV, which is roughly three times of the gas energy in the pump chamber, was delivered by a capacitor bank. From the current-voltage relationship the discharge develops at rapidly decreasing voltage. Pressure at the combustion chamber indicating significant underpressure as well as overpressure peaks is followed by an increase of static pressure level. These data are not yet completely understood. However, Lorentz forces are believed to generate pinching with subsequent pinch heating, resulting in fast pressure variations to be propagated as rarefaction and shock waves, respectively. Utilizing pure axisymmetric electrode initiation rather than often used exploding wire technology in the pump chamber, repeatable experiments were achieved.

  1. Volumetric Fraction Dynamic Measurement in Oil-Water-Gas Multiphase Horizontal Pipe Flow with Dual Energy Gamma-Ray

    NASA Astrophysics Data System (ADS)

    Li, Donghui; Wu, Yingxiang; Wang, Keren; Zhong, Xingfu

    2007-06-01

    The problems of how to measuring the volumetric fractions of oil-water-gas multiphase flow are still a problem remaining to be solved in oil industry. With the technological development of nuclear radioactive inspection, dual-energy γ-ray techniques make it possible to investigate the concentration of the different components on the cross-section of oil-water-gas multiphase pipe-flow. The dual-energy Gamma-ray technique is based on the materials attenuation coefficients measurement. It is comprised of two radioactive isotopes of 241Am and 137Cs with emission energies of 59.5keV and 662keV. In order to measuring the material's attenuation dose rate, some nuclear instruments and data acquisition system were designed; a number of static and dynamic tests were carried out in the Multiphase Laboratory, Institute of Mechanics, Chinese Academy of Sciences. The oil-water-gas three phases of medium have been investigated to simulate different media volumetric fraction distributions on the experimental flow loop. The measurement results of attenuation intensities were obtained; the linear attenuation coefficients and the volumetric fractions were studied and measurement error was discussed in this paper as well.

  2. HIGH EFFICIENCY DESULFURIZATION OF SYNTHESIS GAS

    SciTech Connect

    Kwang-Bok Yi; Anirban Mukherjee; Elizabeth J. Podlaha; Douglas P. Harrison

    2004-03-01

    Mixed metal oxides containing ceria and zirconia have been studied as high temperature desulfurization sorbents with the objective of achieving the DOE Vision 21 target of 1 ppmv or less H{sub 2}S in the product gas. The research was justified by recent results in this laboratory that showed that reduced CeO{sub 2}, designated CeOn (1.5 < n < 2.0), is capable of achieving the 1 ppmv target in highly reducing gas atmospheres. The addition of ZrO{sub 2} has improved the performance of oxidation catalysts and three-way automotive catalysts containing CeO{sub 2}, and was postulated to have similar beneficial effects on CeO{sub 2} desulfurization sorbents. An electrochemical method for synthesizing CeO{sub 2}-ZrO{sub 2} mixtures was developed and the products were characterized by XRD and TEM during year 01. Nanocrystalline particles having a diameter of about 5 nm and containing from approximately 10 mol% to 80 mol% ZrO{sub 2} were prepared. XRD analysis showed the product to be a solid solution at low ZrO{sub 2} contents with a separate ZrO{sub 2} phase emerging at higher ZrO{sub 2} levels. Unfortunately, the quantity of CeO{sub 2}-ZrO{sub 2} that could be prepared electrochemically was too small to permit desulfurization testing. Also during year 01 a laboratory-scale fixed-bed reactor was constructed for desulfurization testing. All components of the reactor and analytical systems that were exposed to low concentrations of H{sub 2}S were constructed of quartz, Teflon, or silcosteel. Reactor product gas composition as a function of time was determined using a Varian 3800 gas chromatograph equipped with a pulsed flame photometric detector (PFPD) for measuring low H{sub 2}S concentrations from approximately 0.1 to 10 ppmv, and a thermal conductivity detector (TCD) for higher concentrations of H{sub 2}S. Larger quantities of CeO{sub 2}-ZrO{sub 2} mixtures from other sources, including mixtures prepared in this laboratory using a coprecipitation procedure, were obtained

  3. High performance hand-held gas chromatograph

    SciTech Connect

    Yu, C M; Koo, J C

    2001-01-10

    Gas chromatography is a prominent technique for separating complex gases and then analyzing the relative quantities of the separate components. This analytical technique is popular with scientists in a wide range of applications, including environmental restoration for air and water pollution, and chemical and biological analysis. Today the analytical instrumentation community is to working towards moving the analysis away from the laboratory to the point of origin of the sample (''the field'') to achieve real-time data collection and lower analysis costs. The Microtechnology Center of Lawrence Livermore National Laboratory, has developed a hand-held, real-time detection gas chromatograph (GC) through Micro-Electro-Mechanical-System (MEMS) technology. The total weight of this GC is approximately 8 pounds, and it measures 8 inches by 5 inches by 3 inches. It consumes approximately 12 watts of electrical power and has a response time on the order of 2 minutes. The current detector is a glow discharge detector with a sensitivity of parts per billion. The average retention time is about 30 to 45 seconds. Under optimum conditions, the calculated effective plate number is 40,000. The separation column in the portable GC is fabricated completely on silicon wafers. Silicon is a good thermal conductor and provides rapid heating and cooling of the column. The operational temperature can be as high as 350 degrees Celsius. The GC system is capable of rapid column temperature ramping and cooling operations. These are especially important for organic and biological analyses in the GC applications.

  4. X-ray gas mass fraction in the Shapley Supercluster and its implication on the cosmological baryon-density parameter

    NASA Astrophysics Data System (ADS)

    Makino, Nobuyoshi; Suto, Yasushi

    1993-04-01

    We estimated the X-ray gas mass of the clusters in the Shapley Supercluster by improving a previous estimate based on the extrapolation from the Coma data. Our estimate of the X-ray gas mass in the Shapley Supercluster, which depends on h50 and beta (a power-law index characterizing the gas density profile around a cluster), turned out to be a factor of 2-4 times smaller than the previous value. We then considered its implication on the baryon density parameter in the universe. Our estimates from the the Shapley Supercluster region are consistent with the predicted range according to the standard big-bang nucleosynthesis model if the universe is open for h50 = 2.0, or if the universe is flat (Omega(0) = 1.0), but with a substantial fraction of (non-baryonic) dark matter existing in intercluster space for h50 = 1.0.

  5. Visualization and void fraction measurement of gas-liquid two-phase flow in plate heat exchanger.

    PubMed

    Asano, H; Takenaka, N; Fujii, T; Maeda, N

    2004-10-01

    Adiabatic and boiling gas-liquid two-phase flows in a simulated plate heat exchanger with a single-ribbed channel were visualized by a thermal neutron radiography method. In the experiments under adiabatic condition, the air-water two-phase flows in an aluminum test section were visualized. In the boiling two-phase flow experiments, chlorofluorocarbon R141b was used as the working fluid. Two-dimensional distributions of void fraction were measured from visualized images via some image processing techniques. As a result, it was shown that both the phases tended to flow straight in the ribbed channel, and mixing of gas and liquid phases was weak. Moreover, when working fluids flew into the test section as a gas-liquid mixture, the phase distributions were strongly affected by a liquid pool at the test section inlet.

  6. HIGH EFFICIENCY DESULFURIZATION OF SYNTHESIS GAS

    SciTech Connect

    Anirban Mukherjee; Kwang-Bok Yi; Elizabeth J. Podlaha; Douglas P. Harrison

    2001-11-01

    Mixed metal oxides containing CeO{sub 2} and ZrO{sub 2} are being studied as high temperature desulfurization sorbents capable of achieving the DOE Vision 21 target of 1 ppmv of less H{sub 2}S. The research is justified by recent results in this laboratory that showed that reduced CeO{sub 2}, designated CeO{sub n} (1.5 < n < 2.0), is capable of achieving the 1 ppmv target in highly reducing gas atmospheres. The addition of ZrO{sub 2} has improved the performance of oxidation catalysts and three-way automotive catalysts containing CeO{sub 2}, and should have similar beneficial effects on CeO{sub 2} desulfurization sorbents. An electrochemical method for synthesizing CeO{sub 2}-ZrO{sub 2} has been developed and the products have been characterized by XRD and TEM during year 01. Nanocrystalline particles having a diameter of about 5 nm and containing from approximately 10 mol% to 80 mol% ZrO{sub 2} have been prepared. XRD showed the product to be a solid solution at low ZrO{sub 2} contents with a separate ZrO{sub 2} phase emerging at higher ZrO{sub 2} levels. Phase separation did not occur when the solid solutions were heat treated at 700 C. A flow reactor system constructed of quartz and teflon has been constructed, and a gas chromatograph equipped with a pulsed flame photometric detector (PFPD) suitable for measuring sub-ppmv levels of H{sub 2}S has been purchased with LSU matching funds. Preliminary desulfurization tests using commercial CeO{sub 2} and CeO{sub 2}-ZrO{sub 2} in highly reducing gas compositions has confirmed that CeO{sub 2}-ZrO{sub 2} is more effective than CeO{sub 2} in removing H{sub 2}S. At 700 C the product H{sub 2}S concentration using CeO{sub 2}-ZrO{sub 2} sorbent was near the 0.1 ppmv PFPD detection limit during the prebreakthrough period.

  7. Statistical correlations in an ideal gas of particles obeying fractional exclusion statistics.

    PubMed

    Pellegrino, F M D; Angilella, G G N; March, N H; Pucci, R

    2007-12-01

    After a brief discussion of the concepts of fractional exchange and fractional exclusion statistics, we report partly analytical and partly numerical results on thermodynamic properties of assemblies of particles obeying fractional exclusion statistics. The effect of dimensionality is one focal point, the ratio mu/k_(B)T of chemical potential to thermal energy being obtained numerically as a function of a scaled particle density. Pair correlation functions are also presented as a function of the statistical parameter, with Friedel oscillations developing close to the fermion limit, for sufficiently large density.

  8. Dry fractionation creates fractions of wheat distillers dried grains and solubles with highly digestible nutrient content for grower pigs.

    PubMed

    Yáñez, J L; Beltranena, E; Zijlstra, R T

    2014-08-01

    Nutrient digestibility in distillers dried grains with solubles (DDGS) is limited by constraints such as particle size and fiber. Wheat DDGS contains more fiber than corn DDGS that may reduce its nutritional value in swine feeds. Dry fractionation may create DDGS fractions with low and high fiber content; therefore, wheat DDGS was processed sequentially using a vibratory sifter and gravity table. Sufficient material was obtained from 3 wheat DDGS fractions that differed in particle size from fine to coarse (Fraction A [FA], Fraction C [FC], and Fraction D [FD]). Five cornstarch-based diets were mixed that contained either 40% wheat DDGS, 30% FA, 30% FC plus 10% soybean meal (SBM), 30% FD plus 15% SBM, or 35% SBM. A sixth, N-free diet served to subtract basal endogenous AA losses and as control for energy digestibility calculations. Six ileal-cannulated barrows (29 kg BW) were fed 6 diets at 2.8 times maintenance for DE in six 9-d periods as a 6 × 6 Latin square. Feces and ileal digesta were collected sequentially for 2 d each. Wheat DDGS FA, FC, and FD were 258, 530, and 723 μm in mean particle size and contained 44.8, 39.3, and 33.8% CP and 29.1, 35.1, and 37.5% in NDF, respectively. The apparent total tract digestibility (ATTD) of GE was greater (P < 0.05) for SBM than wheat DDGS, was greater (P < 0.05) for FA than wheat DDGS, and did not differ between FC, FD, and wheat DDGS. The standardized ileal digestibility (SID) did not differ between SBM and wheat DDGS (P > 0.05) for most AA. The SID of Arg, Lys, Trp, and available Lys was greater (P < 0.05) for FD than wheat DDGS but was similar for FA, FC, and wheat DDGS and was greater (P < 0.05) for FD than SBM. The DE and NE value was greater (P < 0.05) for SBM, FA, and FC than wheat DDGS and did not differ between FD and wheat DDGS. The SID content of indispensable AA and available Lys was greater (P < 0.05) for SBM than wheat DDGS. The SID content of Ile, Leu, Met, Phe, and Val was greater (P < 0.05) for FA than

  9. Ceramic high pressure gas path seal

    NASA Technical Reports Server (NTRS)

    Liotta, G. C.

    1987-01-01

    Stage 1 ceramic shrouds (high pressure turbine gas path seal) were developed for the GE T700 turbine helicopter engine under the Army/NASA Contract NAS3-23174. This contract successfully proved the viability and benefits of a Stage 1 ceramic shroud for production application. Stage 1 ceramic shrouds were proven by extensive component and engine testing. This Stage 1 ceramic shroud, plasma sprayed ceramic (ZrOs-BY2O3) and bond coating (NiCrAlY) onto a cast metal backing, offers significant engine performance improvement. Due to the ceramic coating, the amount of cooling air required is reduced 20% resulting in a 0.5% increase in horsepower and a 0.3% decrease in specific fuel consumption. This is accomplished with a component which is lower in cost than the current production shroud. Stage 1 ceramic shrouds will be introduced into field service in late 1987.

  10. High temperature coatings for gas turbines

    DOEpatents

    Zheng, Xiaoci Maggie

    2003-10-21

    Coating for high temperature gas turbine components that include a MCrAlX phase, and an aluminum-rich phase, significantly increase oxidation and cracking resistance of the components, thereby increasing their useful life and reducing operating costs. The aluminum-rich phase includes aluminum at a higher concentration than aluminum concentration in the MCrAlX alloy, and an aluminum diffusion-retarding composition, which may include cobalt, nickel, yttrium, zirconium, niobium, molybdenum, rhodium, cadmium, indium, cerium, iron, chromium, tantalum, silicon, boron, carbon, titanium, tungsten, rhenium, platinum, and combinations thereof, and particularly nickel and/or rhenium. The aluminum-rich phase may be derived from a particulate aluminum composite that has a core comprising aluminum and a shell comprising the aluminum diffusion-retarding composition.

  11. An Automated High-Throughput System to Fractionate Plant Natural Products for Drug Discovery

    PubMed Central

    Tu, Ying; Jeffries, Cynthia; Ruan, Hong; Nelson, Cynthia; Smithson, David; Shelat, Anang A.; Brown, Kristin M.; Li, Xing-Cong; Hester, John P.; Smillie, Troy; Khan, Ikhlas A.; Walker, Larry; Guy, Kip; Yan, Bing

    2010-01-01

    The development of an automated, high-throughput fractionation procedure to prepare and analyze natural product libraries for drug discovery screening is described. Natural products obtained from plant materials worldwide were extracted and first prefractionated on polyamide solid-phase extraction cartridges to remove polyphenols, followed by high-throughput automated fractionation, drying, weighing, and reformatting for screening and storage. The analysis of fractions with UPLC coupled with MS, PDA and ELSD detectors provides information that facilitates characterization of compounds in active fractions. Screening of a portion of fractions yielded multiple assay-specific hits in several high-throughput cellular screening assays. This procedure modernizes the traditional natural product fractionation paradigm by seamlessly integrating automation, informatics, and multimodal analytical interrogation capabilities. PMID:20232897

  12. Condensate fraction in a 2D Bose gas measured across the Mott-insulator transition.

    PubMed

    Spielman, I B; Phillips, W D; Porto, J V

    2008-03-28

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

  13. Size-exclusion chromatography for the determination of the boiling point distribution of high-boiling petroleum fractions.

    PubMed

    Boczkaj, Grzegorz; Przyjazny, Andrzej; Kamiński, Marian

    2015-03-01

    The paper describes a new procedure for the determination of boiling point distribution of high-boiling petroleum fractions using size-exclusion chromatography with refractive index detection. Thus far, the determination of boiling range distribution by chromatography has been accomplished using simulated distillation with gas chromatography with flame ionization detection. This study revealed that in spite of substantial differences in the separation mechanism and the detection mode, the size-exclusion chromatography technique yields similar results for the determination of boiling point distribution compared with simulated distillation and novel empty column gas chromatography. The developed procedure using size-exclusion chromatography has a substantial applicability, especially for the determination of exact final boiling point values for high-boiling mixtures, for which a standard high-temperature simulated distillation would have to be used. In this case, the precision of final boiling point determination is low due to the high final temperatures of the gas chromatograph oven and an insufficient thermal stability of both the gas chromatography stationary phase and the sample. Additionally, the use of high-performance liquid chromatography detectors more sensitive than refractive index detection allows a lower detection limit for high-molar-mass aromatic compounds, and thus increases the sensitivity of final boiling point determination.

  14. High pressure synthesis gas conversion. Task 3: High pressure profiles

    SciTech Connect

    Not Available

    1993-05-01

    The purpose of this research project was to build and test a high pressure fermentation system for the production of ethanol from synthesis gas. The fermenters, pumps, controls, and analytical system were procured or fabricated and assembled in our laboratory. This system was then used to determine the effects of high pressure on growth and ethanol production by C. 1jungdahlii. The limits of cell concentration and mass transport relationships were found in CSTR and immobilized cell reactors (ICR). The minimum retention times and reactor volumes were found for ethanol production in these reactors.

  15. A picosecond high pressure gas switch

    SciTech Connect

    Cravey, W.R.; Poulsen, P.P.; Pincosy, P.A.

    1992-06-01

    Work is being done to develop a high pressure gas switch (HPGS) with picosecond risetimes for UWB applications. Pulse risetimes on the order of 200 picoseconds have been observed at 1 kHz prf and 1 atmosphere. Calculations show that switching closure times on the order of tens of picoseconds can be achieved at high pressures and higher electric fields. A voltage hold-off of 1 MV/cm has been measured at 10 atmospheres and several MV/cm appears possible with the HPGS. With these high electric field levels, energy storage of tens of Joules in a reasonably sized package is achievable. Initial HPGS performance has been characterized on the WASP pulse generator at LLNL. A detailed description of the switch used for initial testing is given. Switch recovery times of 1-ms have been measured at 1 atmosphere. Data on the switching uniformity, voltage hold-off recovery, and pulse repeatability, is presented. In addition, a physics switch model is described and results are compared with lab data.

  16. Bimodular high temperature planar oxygen gas sensor

    PubMed Central

    Sun, Xiangcheng; Liu, Yixin; Gao, Haiyong; Gao, Pu-Xian; Lei, Yu

    2014-01-01

    A bimodular planar O2 sensor was fabricated using NiO nanoparticles (NPs) thin film coated yttria-stabilized zirconia (YSZ) substrate. The thin film was prepared by radio frequency (r.f.) magnetron sputtering of NiO on YSZ substrate, followed by high temperature sintering. The surface morphology of NiO NPs film was characterized by atomic force microscope (AFM) and scanning electron microscope (SEM). X-ray diffraction (XRD) patterns of NiO NPs thin film before and after high temperature O2 sensing demonstrated that the sensing material possesses a good chemical and structure stability. The oxygen detection experiments were performed at 500, 600, and 800°C using the as-prepared bimodular O2 sensor under both potentiometric and resistance modules. For the potentiometric module, a linear relationship between electromotive force (EMF) output of the sensor and the logarithm of O2 concentration was observed at each operating temperature, following the Nernst law. For the resistance module, the logarithm of electrical conductivity was proportional to the logarithm of oxygen concentration at each operating temperature, in good agreement with literature report. In addition, this bimodular sensor shows sensitive, reproducible and reversible response to oxygen under both sensing modules. Integration of two sensing modules into one sensor could greatly enrich the information output and would open a new venue in the development of high temperature gas sensors. PMID:25191652

  17. Effects of dry bulk density and particle size fraction on gas transport parameters in variably saturated landfill cover soil

    SciTech Connect

    Wickramarachchi, Praneeth; Kawamoto, Ken; Hamamoto, Shoichiro; Nagamori, Masanao; Moldrup, Per; Komatsu, Toshiko

    2011-12-15

    Highlights: > The effects of soil physical properties on gas transport parameters were investigated. > Higher values of D{sub p} and k{sub a} exhibited in the '+gravel' than the '-gravel' fraction at same soil-air content ({epsilon}). > Recent power law models for D{sub p} (WLR) and k{sub a} (RPL) were modified. > Model parameters were linearly related to easily measurable dry bulk density ({rho}{sub b}). - Abstract: Landfill sites are emerging in climate change scenarios as a significant source of greenhouse gases. The compacted final soil cover at landfill sites plays a vital role for the emission, fate and transport of landfill gases. This study investigated the effects of dry bulk density, {rho}{sub b}, and particle size fraction on the main soil-gas transport parameters - soil-gas diffusivity (D{sub p}/D{sub o}, ratio of gas diffusion coefficients in soil and free air) and air permeability (k{sub a}) - under variably-saturated moisture conditions. Soil samples were prepared by three different compaction methods (Standard and Modified Proctor compaction, and hand compaction) with resulting {rho}{sub b} values ranging from 1.40 to 2.10 g cm{sup -3}. Results showed that D{sub p} and k{sub a} values for the '+gravel' fraction (<35 mm) became larger than for the '-gravel' fraction (<2 mm) under variably-saturated conditions for a given soil-air content ({epsilon}), likely due to enhanced gas diffusion and advection through less tortuous, large-pore networks. The effect of dry bulk density on D{sub p} and k{sub a} was most pronounced for the '+gravel' fraction. Normalized ratios were introduced for all soil-gas parameters: (i) for gas diffusivity D{sub p}/D{sub f}, the ratio of measured D{sub p} to D{sub p} in total porosity (f), (ii) for air permeability k{sub a}/k{sub a,pF4.1}, the ratio of measured k{sub a} to k{sub a} at 1235 kPa matric potential (=pF 4.1), and (iii) for soil-air content, the ratio of soil-air content ({epsilon}) to total porosity (f) (air

  18. Performance enhancement of direct ethanol fuel cell using Nafion composites with high volume fraction of titania

    NASA Astrophysics Data System (ADS)

    Matos, B. R.; Isidoro, R. A.; Santiago, E. I.; Fonseca, F. C.

    2014-12-01

    The present study reports on the performance enhancement of direct ethanol fuel cell (DEFC) at 130 °C with Nafion-titania composite electrolytes prepared by sol-gel technique and containing high volume fractions of the ceramic phase. It is found that for high volume fractions of titania (>10 vol%) the ethanol uptake of composites is largely reduced while the proton conductivity at high-temperatures is weakly dependent on the titania content. Such tradeoff between alcohol uptake and conductivity resulted in a boost of DEFC performance at high temperatures using Nafion-titania composites with high fraction of the inorganic phase.

  19. Galaxy Cluster Gas Mass Fractions From Sunyaev-Zel'dovich Effect Measurement: Constraints on Omega_M

    NASA Technical Reports Server (NTRS)

    Grego, Laura; Carlstrom, John E.; Reese, Erik D.; Holder, Gilbert P.; Holzapfel, William L.; Joy, Marshall K.; Mohr, Joseph J.; Patel, Sandeep; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    Using sensitive centimeter-wave receivers mounted on the Owens Valley Radio Observatory and Berkeley-Illinois-Maryland-Association millimeter arrays, we have obtained interferometric measurements of the Sunyaev-Zei'dovich (SZ) effect toward massive galaxy clusters. We use the SZ data to determine the pressure distribution of the cluster gas and, in combination with published X-ray temperatures, to infer the gas mass and total gravitational mass of 18 clusters. The gas mass fraction, fg, is calculated for each cluster, and is extrapolated to the fiducial radius r_{500} using the results of numerical simulations. The mean f_g within r_{500} is 0.081 + 0.009 - 0.011/(h_{100} (statistical uncertainty at 68% confidence level, assuming OmegaM=0.3, OmegaL=0.7). We discuss possible sources of systematic errors in the mean f 9 measurement. We derive an upper limit for OmegaM from this sample under the assumption that the mass composition of clusters within r_{500} reflects the universal mass composition: Omega_M h gas mass f on cosmology through the angular diameter distance and the r_{500} correction factors. For a flat universe (Omegal, = 1 - OmegaM) and h=0.7, we find the measured gas mass fractions are consistent with OmegaM less than 0.40, at 68% confidence. Including estimates of the baryons contained in galaxies and the baryons which failed to become bound during the cluster formation process, we find OmegaM\\approximately 0.25.

  20. Galaxy Cluster Gas Mass Fractions From Sunyaev-Zel'dovich Effect Measurement: Constraints on Omega_M

    NASA Technical Reports Server (NTRS)

    Grego, Laura; Carlstrom, John E.; Reese, Erik D.; Holder, Gilbert P.; Holzapfel, William L.; Joy, Marshall K.; Mohr, Joseph J.; Patel, Sandeep; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    Using sensitive centimeter-wave receivers mounted on the Owens Valley Radio Observatory and Berkeley-Illinois-Maryland-Association millimeter arrays, we have obtained interferometric measurements of the Sunyaev-Zei'dovich (SZ) effect toward massive galaxy clusters. We use the SZ data to determine the pressure distribution of the cluster gas and, in combination with published X-ray temperatures, to infer the gas mass and total gravitational mass of 18 clusters. The gas mass fraction, fg, is calculated for each cluster, and is extrapolated to the fiducial radius r_{500} using the results of numerical simulations. The mean f_g within r_{500} is 0.081 + 0.009 - 0.011/(h_{100} (statistical uncertainty at 68% confidence level, assuming OmegaM=0.3, OmegaL=0.7). We discuss possible sources of systematic errors in the mean f 9 measurement. We derive an upper limit for OmegaM from this sample under the assumption that the mass composition of clusters within r_{500} reflects the universal mass composition: Omega_M h gas mass f on cosmology through the angular diameter distance and the r_{500} correction factors. For a flat universe (Omegal, = 1 - OmegaM) and h=0.7, we find the measured gas mass fractions are consistent with OmegaM less than 0.40, at 68% confidence. Including estimates of the baryons contained in galaxies and the baryons which failed to become bound during the cluster formation process, we find OmegaM\\approximately 0.25.

  1. Fractionation of highly siderophile and chalcogen elements in components of EH3 chondrites

    NASA Astrophysics Data System (ADS)

    Kadlag, Yogita; Becker, Harry

    2015-07-01

    Abundances of highly siderophile elements (HSE: Re, platinum group elements and Au), chalcogens (Te, Se and S), 187Os/188Os and the major and minor elements Mg, Ca, Mn, Fe, Ni and Co were determined in the components of Sahara 97072 (EH3, find) and Kota Kota (EH3, find) in order to understand the element fractionation processes. In a 187Re-187Os isochron diagram, most magnetic components lie close to the 4.56 Ga IIIA iron meteorite isochron, whereas most other components show deviations from the isochron caused by late redistribution of Re, presumably during terrestrial weathering. Metal- and sulfide rich magnetic fractions and metal-sulfide nodules are responsible for the higher 187Os/188Os in bulk rocks of EH chondrites compared to CI chondrites. The HSE and chalcogens are enriched in magnetic fractions relative to slightly magnetic and nonmagnetic fractions and bulk compositions, indicating that Fe-Ni metal is the main host phase of the HSE in enstatite chondrites. HSE abundance patterns indicate mixing of two components, a CI chondrite like end member and an Au-enriched end member. Because of the decoupled variations of Au from those of Pd or the chalcogens, the enrichment of Au in EH metal cannot be due to metal-sulfide-silicate partitioning processes. Metal and sulfide rich nodules may have formed by melting and reaction of pre-existing refractory element rich material with volatile rich gas. A complex condensation and evaporation history is required to account for the depletion of elements having very different volatility than Au in EH chondrites. The depletions of Te relative to HSE, Se and S in bulk EH chondrites are mainly caused by the depletion of Te in metal. S/Se and S/Mn are lower than in CI chondrites in almost all components and predominantly reflect volatility-controlled loss of sulfur. The latter most likely occurred during thermal processing of dust in the solar nebula (e.g., during chondrule formation), followed by the non-systematic loss of S

  2. Can two-dimensional gas chromatography/mass spectrometric identification of bicyclic aromatic acids in petroleum fractions help to reveal further details of aromatic hydrocarbon biotransformation pathways?

    PubMed

    West, Charles E; Pureveen, Jos; Scarlett, Alan G; Lengger, Sabine K; Wilde, Michael J; Korndorffer, Frans; Tegelaar, Erik W; Rowland, Steven J

    2014-05-15

    The identification of key acid metabolites ('signature' metabolites) has allowed significant improvements to be made in our understanding of the biodegradation of petroleum hydrocarbons, in reservoir and in contaminated natural systems, such as aquifers and seawater. On this basis, anaerobic oxidation is now more widely accepted as one viable mechanism, for instance. However, identification of metabolites in the complex acid mixtures from petroleum degradation is challenging and would benefit from use of more highly resolving analytical methods. Comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GCxGC/TOFMS) with both nominal mass and accurate mass measurement was used to study the complex mixtures of aromatic acids (as methyl esters) in petroleum fractions. Numerous mono- and di-aromatic acid isomers were identified in a commercial naphthenic acids fraction from petroleum and in an acids fraction from a biodegraded petroleum. In many instances, compounds were identified by comparison of mass spectral and retention time data with those of authentic compounds. The identification of a variety of alkyl naphthalene carboxylic and alkanoic and alkyl tetralin carboxylic and alkanoic acids, plus identifications of a range of alkyl indane acids, provides further evidence for 'signature' metabolites of biodegradation of aromatic petroleum hydrocarbons. Identifications such as these now offer the prospect of better differentiation of metabolites of bacterial processes (e.g. aerobic, methanogenic, sulphate-reducing) in polar petroleum fractions. Copyright © 2014 John Wiley & Sons, Ltd.

  3. NEARBY CLUMPY, GAS RICH, STAR-FORMING GALAXIES: LOCAL ANALOGS OF HIGH-REDSHIFT CLUMPY GALAXIES

    SciTech Connect

    Garland, C. A.; Pisano, D. J.; Rabidoux, K.; Low, M.-M. Mac; Kreckel, K.; Guzmán, R. E-mail: djpisano@mail.wvu.edu E-mail: mordecai@amnh.org E-mail: guzman@astro.ufl.edu

    2015-07-10

    Luminous compact blue galaxies (LCBGs) have enhanced star formation rates (SFRs) and compact morphologies. We combine Sloan Digital Sky Survey data with H i data of 29 LCBGs at redshift z ∼ 0 to understand their nature. We find that local LCBGs have high atomic gas fractions (∼50%) and SFRs per stellar mass consistent with some high-redshift star-forming galaxies (SFGs). Many local LCBGs also have clumpy morphologies, with clumps distributed across their disks. Although rare, these galaxies appear to be similar to the clumpy SFGs commonly observed at z ∼ 1–3. Local LCBGs separate into three groups: (1) interacting galaxies (∼20%); (2) clumpy spirals (∼40%); and (3) non-clumpy, non-spirals with regular shapes and smaller effective radii and stellar masses (∼40%). It seems that the method of building up a high gas fraction, which then triggers star formation, is not the same for all local LCBGs. This may lead to a dichotomy in galaxy characteristics. We consider possible gas delivery scenarios and suggest that clumpy spirals, preferentially located in clusters and with companions, are smoothly accreting gas from tidally disrupted companions and/or intracluster gas enriched by stripped satellites. Conversely, as non-clumpy galaxies are preferentially located in the field and tend to be isolated, we suggest clumpy, cold streams, which destroy galaxy disks and prevent clump formation, as a likely gas delivery mechanism for these systems. Other possibilities include smooth cold streams, a series of minor mergers, or major interactions.

  4. The Prospects for Constraining Dark Energy withFuture X-ray Cluster Gas Mass Fraction Measurements

    SciTech Connect

    Rapetti, David; Allen, Steven W.

    2007-10-15

    We examine the ability of a future X-ray observatory, with capabilities similar to those planned for the Constellation-X mission, to constrain dark energy via measurements of the cluster X-ray gas mass fraction, fgas. We find that fgas measurements for a sample of {approx}500 hot (kT{approx}> 5keV), X-ray bright, dynamically relaxed clusters, to a precision of {approx}5 percent, can be used to constrain dark energy with a Dark Energy Task Force (DETF; Albrecht et al. 2006) figure of merit of 20-50. Such constraints are comparable to those predicted by the DETF for other leading, planned 'Stage IV' dark energy experiments. A future fgas experiment will be preceded by a large X-ray or SZ survey that will find hot, X-ray luminous clusters out to high redshifts. Short 'snapshot' observations with the new X-ray observatory should then be able to identify a sample of {approx}500 suitably relaxed systems. The redshift, temperature and X-ray luminosity range of interest has already been partially probed by existing X-ray cluster surveys which allow reasonable estimates of the fraction of clusters that will be suitably relaxed for fgas work to be made; these surveys also show that X-ray flux contamination from point sources is likely to be small for the majority of the targets of interest. Our analysis uses a Markov Chain Monte Carlo method which fully captures the relevant degeneracies between parameters and facilities the incorporation of priors and systematic uncertainties in the analysis. We explore the effects of such uncertainties, for scenarios ranging from optimistic to pessimistic. We conclude that the fgas experiment offers a competitive and complementary approach to the best other large, planned dark energy experiments. In particular, the fgas experiment will provide tight constraints on the mean matter and dark energy densities, with a peak sensitivity for dark energy work at redshifts midway between those of supernovae and baryon acoustic oscillation

  5. Determination of the rod-wise fission gas release fraction in a complete fuel assembly using non-destructive gamma emission tomography

    NASA Astrophysics Data System (ADS)

    Holcombe, Scott; Andersson, Peter; Svärd, Staffan Jacobsson; Hallstadius, Lars

    2016-11-01

    A gamma tomography instrument has been developed at the Halden Boiling Water Reactor (HBWR) in cooperation between the Institute for Energy Technology, Westinghouse (Sweden) and Uppsala University. The instrument is used to record the gamma radiation field surrounding complete fuel assemblies and consists of a shielded enclosure with fixtures to accurately position the fuel and detector relative to each other. A High Purity Germanium detector is used for acquiring high-resolution spectroscopic data, allowing for analysis of multiple gamma-ray peaks. Using the data extracted from the selected peaks, tomographic reconstruction algorithms are used to reproduce the corresponding spatial gamma-ray source distributions within the fuel assembly. With this method, rod-wise data can be can be deduced without the need to dismantle the fuel. In this work, the tomographic device has been experimentally benchmarked for non-destructive rod-wise determination of the Fission Gas Release (FGR) fraction. Measurements were performed on the fuel-stack and gas-plenum regions of a complete fuel assembly, and quantitative tomographic reconstructions of the measurement data were performed in order to determine the rod-wise ratio of 85Kr in the gas plenum to 137Cs in the fuel stack. The rod-wise ratio of 85Kr/137Cs was, in turn, used to calculate the rod-wise FGR fraction. In connection to the tomographic measurements, the fuel rods were also measured individually using gamma scanning in order to provide an experimental benchmark for the tomographic method. Fuel rods from two donor driver fuel assemblies were placed into a nine-rod HBWR driver fuel assembly configuration. In order to provide a challenging measurement object and thus an appropriate benchmark for the tomographic method, five rods were taken from an assembly with a burnup of 51 MWd/kgUO2, and four rods were from an assembly with a burnup of 26 MWd/kgUO2. At the time of the measurements, the nine rods had cooled for

  6. Influence of Albizia lebbeck Saponin and Its Fractions on In Vitro Gas Production Kinetics, Rumen Methanogenesis, and Rumen Fermentation Characteristics

    PubMed Central

    Sirohi, Sunil Kumar; Goel, Navneet; Singh, Nasib

    2014-01-01

    The present study was undertaken to investigate the effect of crude seed powder (CSP) and gross saponins extract (GSE) of seeds of Albizia lebbeck on antimicrobial activity by taking two Gram-positive (Staphylococcus aureus and Bacillus cereus), two Gram-negative (Escherichia coli and Salmonella Typhi) bacteria, and two fungi species (Aspergillus niger and Candida butyric) were taken at 25, 50, 100, 250, and 500 µg levels using agar well diffusion method. Zone of inhibition was increased with increasing of concentration of CSP and saponins which indicates that Gram-negative bacteria (E. coli), Gram-positive bacteria (B. cereus), and A. niger were significantly susceptible to inhibition. Another experiment was conducted to study the effect of GSE and saponins fraction A and B of A. lebbeck supplementation at 6% on DM basis on methane production and other rumen fermentation parameters using in vitro gas production test, by taking three different type diets, that is, high fiber diet (D1, 60R : 40C), medium fiber diet (D2, 50R : 50C), and low fiber diet (D3, 40R : 60C). Significant (P ≤ 0.05) increase was seen in IVDMD, methane production; however ammonia nitrogen concentration decreased as compared to control. The methane production was reduced in a range between 12 and 49% by saponin supplemented diets except in case of GSE in D2. Sap A showed the highest methane reduction per 200 mg of truly digested substrate (TDS) than other treatment groups. Results in relation with quantification of methanogens and protozoa by qPCR indicated the decreasing trend with saponins of A. lebbek in comparison with control except total methanogen quantified using mcr-A based primer. PMID:24977047

  7. An Efficient Algorithm for Some Highly Nonlinear Fractional PDEs in Mathematical Physics

    PubMed Central

    Ahmad, Jamshad; Mohyud-Din, Syed Tauseef

    2014-01-01

    In this paper, a fractional complex transform (FCT) is used to convert the given fractional partial differential equations (FPDEs) into corresponding partial differential equations (PDEs) and subsequently Reduced Differential Transform Method (RDTM) is applied on the transformed system of linear and nonlinear time-fractional PDEs. The results so obtained are re-stated by making use of inverse transformation which yields it in terms of original variables. It is observed that the proposed algorithm is highly efficient and appropriate for fractional PDEs and hence can be extended to other complex problems of diversified nonlinear nature. PMID:25525804

  8. An efficient algorithm for some highly nonlinear fractional PDEs in mathematical physics.

    PubMed

    Ahmad, Jamshad; Mohyud-Din, Syed Tauseef

    2014-01-01

    In this paper, a fractional complex transform (FCT) is used to convert the given fractional partial differential equations (FPDEs) into corresponding partial differential equations (PDEs) and subsequently Reduced Differential Transform Method (RDTM) is applied on the transformed system of linear and nonlinear time-fractional PDEs. The results so obtained are re-stated by making use of inverse transformation which yields it in terms of original variables. It is observed that the proposed algorithm is highly efficient and appropriate for fractional PDEs and hence can be extended to other complex problems of diversified nonlinear nature.

  9. High-temperature Gas Reactor (HTGR)

    NASA Astrophysics Data System (ADS)

    Abedi, Sajad

    2011-05-01

    General Atomics (GA) has over 35 years experience in prismatic block High-temperature Gas Reactor (HTGR) technology design. During this period, the design has recently involved into a modular have been performed to demonstrate its versatility. This versatility is directly related to refractory TRISO coated - particle fuel that can contain any type of fuel. This paper summarized GA's fuel cycle studies individually and compares each based upon its cycle sustainability, proliferation-resistance capabilities, and other performance data against pressurized water reactor (PWR) fuel cycle data. Fuel cycle studies LEU-NV;commercial HEU-Th;commercial LEU-Th;weapons-grade plutonium consumption; and burning of LWR waste including plutonium and minor actinides in the MHR. results show that all commercial MHR options, with the exception of HEU-TH, are more sustainable than a PWR fuel cycle. With LEU-NV being the most sustainable commercial options. In addition, all commercial MHR options out perform the PWR with regards to its proliferation-resistance, with thorium fuel cycle having the best proliferation-resistance characteristics.

  10. High-speed pectic enzyme fractionation by immobilised metal ion affinity membranes.

    PubMed

    Camperi, S A; Grasselli, M; Cascone, O

    2000-01-01

    Immobilised metal ion affinity polysulfone hollow-fibre membranes, with a high capacity for protein adsorption, were prepared and their utilisation for commercial pectic enzyme fractionation was studied. The pass-through fraction containing pectinlyase is useful for fruit-juice clarification without methanol production on account of pectinesterase being retained by the IDA-Cu2+ membrane.

  11. [Study of the fatty acid components of the triglyceride fraction of the blood in normal and thalassemic subjects, using gas chromatography].

    PubMed

    Gilli, G; Moiraghi Ruggenini, A; Nani, E; Bottura, G; Mastretta, L

    1977-01-01

    Thin layer chromatography was used to separate the triglyceridic fraction of plasma lipides in normal (19) and thalassaemic (15) subjects. Gas chromatographic analysis of the fraction was then carried out and the fatty acids represented were identified qualitatively and quantitatively. Statistically significant variations, specifically increase in arachidonic acid and reduction in palmitic and linoleic acids, were observed in the thalassaemic patients.

  12. Redshift evolution of stellar mass versus gas fraction relation in 0 < z < 2 regime: observational constraint for galaxy formation models

    NASA Astrophysics Data System (ADS)

    Morokuma-Matsui, Kana; Baba, Junichi

    2015-12-01

    We investigate the redshift evolution of molecular gas mass fraction (f_mol = M_mol/M_star +M_mol, where Mmol is molecular gas mass and M⋆ is stellar mass) of galaxies in the redshift range of 0 < z < 2 as a function of the stellar mass by combining carbon monoxide (CO) literature data. We observe a stellar-mass dependence of the fmol evolution where massive galaxies have largely depleted their molecular gas at z = 1, whereas the fmol value of less massive galaxies drastically decreases from z = 1. We compare the observed M⋆ - fmol relation with theoretical predictions from cosmological hydrodynamic simulations and semi-analytical models for galaxy formation. Although the theoretical studies approximately reproduce the observed mass dependence of the fmol evolution, they tend to underestimate the fmol values, particularly of less massive (<1010 M⊙) and massive galaxies (>1011 M⊙) when compared with the observational values. Our result suggests the importance of the feedback models which suppress the star formation while simultaneously preserving the molecular gas in order to reproduce the observed M⋆ - fmol relation.

  13. Analysis of oxidised heavy paraffininc products by high temperature comprehensive two-dimensional gas chromatography.

    PubMed

    Potgieter, H; Bekker, R; Beigley, J; Rohwer, E

    2017-08-04

    Heavy petroleum fractions are produced during crude and synthetic crude oil refining processes and they need to be upgraded to useable products to increase their market value. Usually these fractions are upgraded to fuel products by hydrocracking, hydroisomerization and hydrogenation processes. These fractions are also upgraded to other high value commercial products like lubricant oils and waxes by distillation, hydrogenation, and oxidation and/or blending. Oxidation of hydrogenated heavy paraffinic fractions produces high value products that contain a variety of oxygenates and the characterization of these heavy oxygenates is very important for the control of oxidation processes. Traditionally titrimetric procedures are used to monitor oxygenate formation, however, these titrimetric procedures are tedious and lack selectivity toward specific oxygenate classes in complex matrices. Comprehensive two-dimensional gas chromatography (GC×GC) is a way of increasing peak capacity for the comprehensive analysis of complex samples. Other groups have used HT-GC×GC to extend the carbon number range attainable by GC×GC and have optimised HT-GC×GC parameters for the separation of aromatics, nitrogen-containing compounds as well as sulphur-containing compounds in heavy petroleum fractions. HT-GC×GC column combinations for the separation of oxygenates in oxidised heavy paraffinic fractions are optimised in this study. The advantages of the HT-GC×GC method in the monitoring of the oxidation reactions of heavy paraffinic fraction samples are illustrated. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Electrochemical high-temperature gas sensors

    NASA Astrophysics Data System (ADS)

    Saruhan, B.; Stranzenbach, M.; Yüce, A.; Gönüllü, Y.

    2012-06-01

    Combustion produced common air pollutant, NOx associates with greenhouse effects. Its high temperature detection is essential for protection of nature. Component-integration capable high-temperature sensors enable the control of combustion products. The requirements are quantitative detection of total NOx and high selectivity at temperatures above 500°C. This study reports various approaches to detect NO and NO2 selectively under lean and humid conditions at temperatures from 300°C to 800°C. All tested electrochemical sensors were fabricated in planar design to enable componentintegration. We suggest first an impedance-metric gas sensor for total NOx-detection consisting of NiO- or NiCr2O4-SE and PYSZ-electrolyte. The electrolyte-layer is about 200μm thickness and constructed of quasi-single crystalline columns. The sensing-electrode (SE) is magnetron sputtered thin-layers of NiO or NiCr2O4. Sensor sensitivity for detection of total NOx has been measured by applying impedance analysis. The cross-sensitivity to other emission gases such as CO, CO2, CH4 and oxygen (5 vol.%) has been determined under 0-1000ppm NO. Sensor maintains its high sensitivity at temperatures up to 550°C and 600°C, depending on the sensing-electrode. NiO-SE yields better selectivity to NO in the presence of oxygen and have shorter response times comparing to NiCr2O4-SE. For higher temperature NO2-sensing capability, a resistive DC-sensor having Al-doped TiO2-sensing layers has been employed. Sensor-sensitivity towards NO2 and cross-sensitivity to CO has been determined in the presence of H2O at temperatures 600°C and 800°C. NO2 concentrations varying from 25 to 100ppm and CO concentrations from 25 to 75ppm can be detected. By nano-tubular structuring of TiO2, NO2 sensitivity of the sensor was increased.

  15. Plant- versus microbial signature in densimetric fractions of mediterranean forest soils: a study by thermochemolysis gas chromatography mass spectrometry

    NASA Astrophysics Data System (ADS)

    Rovira, Pere; Grasset, Laurent

    2015-04-01

    Plant- versus microbial signature in densimetric fractions of mediterranean forest soils: a study by thermochemolysis gas chromatography mass spectrometry The ageing of a given organic substrate decomposing in soil is strongly dependant of its microbial utilization and transformation (reworking) by the soil microflora. How far a given substrate or soil fraction has gone in this evolution is usually measured by means of molecular signatures, ratios between organic compounds which enlighten us about the origin and/or the degree of microbial reworking of a specific group of compounds: lipids, proteins, lignin, carbohydrates, etc. Owing to the biochemical heterogeneity of decomposing substrates it is unlikely that the degree of microbial reworking can be approached with a single signature. Applying a couple of them is much better, but obtaining a wide collection of molecular signatures can be time consuming. Here, instead of applying specific methods to obtain a collection of specific signatures, we apply TMAH-thermochemolysis to obtain a panoramic view of the biochemical composition of a series of densimetric fractions of soils. From the compounds identified after TMAH-thermochemolysis, a collection of indicators was obtained: (a) ratio between short and long-chained linear alkanoic acids; (b) ratio between branched and long-chained linear alkanoic acids; (c) ratio between C16 and total alpha-omega-alkanedioic acids; (d) ratio microbial to plant-derived 1-methoxyalkanes; (e) ratio syringyl to total lignin-derived phenolic compounds; (f) vanillic acid to vanillin ratio; (g) fucose/glucose ratio; and (h) xylose/glucose ratio. From these indicators a single numerical value is distilled, allowing to order a couple of densimetric fractions of soil organic matter according to its degree of microbial reworking. This approach was applied to the comparison of a couple of densimetric fractions of soil organic matter of three organic H horizons from mediterranean forest soils

  16. High temperature desulfurization of synthesis gas

    DOEpatents

    Najjar, Mitri S.; Robin, Allen M.

    1989-01-01

    The hot process gas stream from the partial oxidation of sulfur-containing heavy liquid hydrocarbonaceous fuel and/or sulfur-containing solid carbonaceous fuel comprising gaseous mixtures of H.sub.2 +CO, sulfur-containing gases, entrained particulate carbon, and molten slag is passed through the unobstructed central passage of a radiant cooler where the temperature is reduced to a temperature in the range of about 1800.degree. F. to 1200.degree. F. From about 0 to 95 wt. % of the molten slag and/or entrained material may be removed from the hot process gas stream prior to the radiant cooler with substantially no reduction in temperature of the process gas stream. In the radiant cooler, after substantially all of the molten slag has solidified, the sulfur-containing gases are contacted with a calcium-containing material to produce calcium sulfide. A partially cooled stream of synthesis gas, reducing gas, or fuel gas containing entrained calcium sulfide particulate matter, particulate carbon, and solidified slag leaves the radiant cooler containing a greatly reduced amount of sulfur-containing gases.

  17. Analysis of the unsaponifiable fraction of lipids belonging to various milk-types by using comprehensive two-dimensional gas chromatography with dual mass spectrometry/flame ionization detection and with the support of high resolution time-of-flight mass spectrometry for structural elucidation.

    PubMed

    Tranchida, Peter Q; Salivo, Simona; Bonaccorsi, Ivana; Rotondo, Archimede; Dugo, Paola; Mondello, Luigi

    2013-10-25

    The present investigation is focused on the use of a comprehensive two-dimensional GC (GC×GC) method, with dual mass spectrometry/flame ionization detection (MS/FID), for the qualitative and quantitative analysis of the unsaponifiable fraction of milk lipids (cow butter, buffalo, ewe, and goat milks). The structure of many constituents (particularly sterols) was confirmed by using GC-high resolution time-of-flight MS. The GC×GC column set used consisted of a low-polarity first dimension, and a medium-polarity secondary one, both characterized by a high thermal stability. The use of dual detection enabled the attainment of both mass spectral information and relative % FID data. The complexity of the fingerprint, generated by the unsaponifiable fraction, justified the employment of the two-dimensional GC technology. However, it was two other GC×GC characteristics that contributed most to the attainment of promising results, namely sensitivity enhancement and the formation of group-type patterns. Because many milk lipid constituents were not contained in the MS databases employed, exact mass information proved to be valuable for identification purposes.

  18. Off-line high-pH reversed-phase fractionation for in-depth phosphoproteomics.

    PubMed

    Batth, Tanveer S; Francavilla, Chiara; Olsen, Jesper V

    2014-12-05

    Protein phosphorylation is an important post-translational modification (PTM) involved in embryonic development, adult homeostasis, and disease. Over the past decade, several advances have been made in liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based technologies to identify thousands of phosphorylation sites. However, in-depth phosphoproteomics often require off-line enrichment and fractionation techniques. In this study, we provide a detailed analysis of the physicochemical characteristics of phosphopeptides, which have been fractionated by off-line high-pH chromatography (HpH) before subsequent titanium dioxide (TiO2) enrichment and LC-MS/MS analysis. Our results demonstrate that HpH is superior to standard strong-cation exchange (SCX) fractionation in the total number of phosphopeptides detected when analyzing the same number of fractions by identical LC-MS/MS gradients. From 14 HpH fractions, we routinely identified over 30,000 unique phosphopeptide variants, which is more than twice the number of that obtained from SCX fractionation. HpH chromatography displayed an exceptional ability to fractionate singly phosphorylated peptides, with minor benefits for doubly phosphorylated peptides over that with SCX. Further optimizations in the pooling and concatenation strategy increased the total number of multiphosphorylated peptides detected after HpH fractionation. In conclusion, we provide a basic framework and resource for performing in-depth phosphoproteome studies utilizing off-line basic reversed-phased fractionation. Raw data is available at ProteomeXchange (PXD001404).

  19. Fractional ventilation mapping using inert fluorinated gas MRI in rat models of inflammation and fibrosis.

    PubMed

    Couch, Marcus J; Fox, Matthew S; Viel, Chris; Gajawada, Gowtham; Li, Tao; Ouriadov, Alexei V; Albert, Mitchell S

    2016-05-01

    The purpose of this study was to extend established methods for fractional ventilation mapping using (19) F MRI of inert fluorinated gases to rat models of pulmonary inflammation and fibrosis. In this study, five rats were instilled with lipopolysaccharide (LPS) in the lungs two days prior to imaging, six rats were instilled with bleomycin in the lungs two weeks prior to imaging and an additional four rats were used as controls. (19) F MR lung imaging was performed at 3 T with rats continuously breathing a mixture of sulfur hexafluoride and O2 . Fractional ventilation maps were obtained using a wash-out approach, by switching the breathing mixture to pure O2 , and acquiring images following each successive wash-out breath. The mean fractional ventilation (r) was 0.29 ± 0.05 for control rats, 0.23 ± 0.10 for LPS-instilled rats and 0.19 ± 0.03 for bleomycin-instilled rats. Bleomycin-instilled rats had a significantly decreased mean r value compared with controls (P = 0.010). Although LPS-instilled rats had a slightly reduced mean r value, this trend was not statistically significant (P = 0.556). Fractional ventilation gradients were calculated in the anterior/posterior (A/P) direction, and the mean A/P gradient was -0.005 ± 0.008 cm(-1) for control rats, 0.013 ± 0.005 cm(-1) for LPS-instilled rats and 0.009 ± 0.018 cm(-1) for bleomycin-instilled rats. Fractional ventilation gradients were significantly different for control rats compared with LPS-instilled rats only (P = 0.016). The ventilation gradients calculated from control rats showed the expected gravitational relationship, while ventilation gradients calculated from LPS- and bleomycin-instilled rats showed the opposite trend. Histology confirmed that LPS-instilled rats had a significantly elevated alveolar wall thickness, while bleomycin-instilled rats showed signs of substantial fibrosis. Overall, (19)F MRI may be able to detect the effects of pulmonary

  20. HIGH EFFICIENCY DESULFURIZATION OF SYNTHESIS GAS

    SciTech Connect

    Kwang-Bok Yi; Elizabeth J. Podlaha; Douglas P. Harrison

    2003-11-01

    Mixed metal oxides containing CeO{sub 2} and ZrO{sub 2} are being studied as high temperature desulfurization sorbents capable of achieving the DOE Vision 21 target of 1 ppmv or less H{sub 2}S. The research is justified by recent results in this laboratory that showed that reduced CeO{sub 2}, designated CeOn (1.5 < n < 2.0), is capable of achieving the 1 ppmv target in highly reducing gas atmospheres. The addition of ZrO{sub 2} has improved the performance of oxidation catalysts and three-way automotive catalysts containing CeO{sub 2}, and should have similar beneficial effects on CeO{sub 2} desulfurization sorbents. An electrochemical method for synthesizing CeO{sub 2}-ZrO{sub 2} was developed and the products were characterized by XRD and TEM during year 01. Nanocrystalline particles having a diameter of about 5 nm and containing from approximately 10 mol% to 80 mol% ZrO{sub 2} were prepared. XRD analysis showed the product to be a solid solution at low ZrO{sub 2} contents with a separate ZrO{sub 2} phase emerging at higher ZrO{sub 2} levels. Unfortunately, the quantity of CeO{sub 2}-ZrO{sub 2} that could be prepared electrochemically was too small to permit full desulfurization testing. Also during year 01 a laboratory-scale fixed-bed reactor was constructed for desulfurization testing. All components of the reactor and analytical systems that may be exposed to low concentrations of H{sub 2}S are constructed of quartz, Teflon, or silcosteel. Reactor product gas composition as a function of time is determined using a Varian 3800 gas chromatograph equipped with a pulsed flame photometric detector (PFPD) for measuring low H{sub 2}S concentrations (<{approx}10 ppmv) and a thermal conductivity detector (TCD) for higher concentrations of H{sub 2}S. Larger quantities of CeO{sub 2}-ZrO{sub 2} mixtures from other sources, including mixtures prepared in this laboratory using a coprecipitation procedure, have been obtained. Much of the work during year 02 consisted of

  1. HIGH EFFICIENCY DESULFURIZATION OF SYNTHESIS GAS

    SciTech Connect

    Kwang-Bok Yi; Elizabeth J. Podlaha; Douglas P. Harrison

    2002-11-01

    Mixed metal oxides containing CeO{sub 2} and ZrO{sub 2} are being studied as high temperature desulfurization sorbents capable of achieving the DOE Vision 21 target of 1 ppmv or less H{sub 2}S. The research is justified by recent results in this laboratory that showed that reduced CeO{sub 2}, designated CeO{sub n} (1.5 < n < 2.0), is capable of achieving the 1 ppmv target in highly reducing gas atmospheres. The addition of ZrO{sub 2} has improved the performance of oxidation catalysts and three-way automotive catalysts containing CeO{sub 2}, and should have similar beneficial effects on CeO{sub 2} desulfurization sorbents. An electrochemical method for synthesizing CeO{sub 2}-ZrO{sub 2} was developed and the products were characterized by XRD and TEM during year 01. Nanocrystalline particles having a diameter of about 5 nm and containing from approximately 10 mol% to 80 mol% ZrO{sub 2} were prepared. XRD showed the product to be a solid solution at low ZrO{sub 2} contents with a separate ZrO{sub 2} phase emerging at higher ZrO{sub 2} levels. Unfortunately, the quantity of CeO{sub 2}-ZrO{sub 2} that could be prepared electrochemically was too small to permit full testing in our desulfurization reactor. Also during year 01 a laboratory-scale fixed-bed reactor was constructed for desulfurization testing. All components of the reactor and analytical systems that may be exposed to low concentrations of H{sub 2}S are constructed of quartz, Teflon, or silcosteel. Reactor product gas composition as a function of time is determined using a Varian 3800 gas chromatograph equipped with a pulsed flame photometric detector (PFPD) for measuring low H{sub 2}S concentrations ({approx}< 10 ppmv) and a thermal conductivity detector (TCD) for higher concentrations of H{sub 2}S. Larger quantities of CeO{sub 2}-ZrO{sub 2} mixtures from other sources, including mixtures prepared in this laboratory using a coprecipitation procedure, have been obtained. Characterization and desulfurization

  2. High-dose, conventionally fractionated thoracic reirradiation for lung tumors.

    PubMed

    Griffioen, Gwendolyn H M J; Dahele, Max; de Haan, Patricia F; van de Ven, Peter M; Slotman, Ben J; Senan, Suresh

    2014-03-01

    Loco-regional recurrences and second primary lung tumors are not uncommon after high-dose thoracic radiotherapy. The availability of improved radiotherapy techniques increases options for reirradiation. We describe a single-institutional experience with high-dose conventional thoracic reirradiation for both loco-regional recurrences and new primary tumors. Retrospective chart review of patients undergoing reirradiation between February 2004 and February 2013. Of 24 patients identified, 54% had a loco-regional recurrence, and 46% a new primary tumor. The majority (63%) had stage III NSCLC at both initial and second treatment; median interval between treatments was 51 months (5-189), median follow-up after reirradiation was 19.3 months (95% CI: 2.8-35.9). Median overall survival (OS) after reirradiation was 13.5 months, with 1-year survival 51%. Median event-free survival (EFS) was 8.4 months. Median time between reirradiation and local progression (n=8) or distant progression (n=8) was 6.7 and 11.8 months, respectively. Three patients died with possible grade 5 bleeding. Other toxicities were uncommon. Planning target volume (PTV) at reirradiation was the most important prognostic factor; PTV <300 versus ≥300cc was significantly associated with median OS (17.4 vs 8.2 months, p=0.03) and EFS (14.1 vs 5.5 months, p=0.03). Magnitude of overlap between the initial and subsequent PTVs, and between dose distributions, did not influence survival. Thoracic reirradiation with high dose conventional radiotherapy appears to deliver a meaningful survival benefit in low volume new primary or recurrent lung cancer. Further studies are needed to confirm these findings, and to establish reliable normal tissue tolerance doses for reirradiation. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  3. Effect of high pressure high temperature processing on the volatile fraction of differently coloured carrots.

    PubMed

    Kebede, Biniam T; Grauwet, Tara; Palmers, Stijn; Vervoort, Liesbeth; Carle, Reinhold; Hendrickx, Marc; Van Loey, Ann

    2014-06-15

    To get deeper insight into the effect of high pressure high temperature (HPHT) processing on the volatile fraction of carrots, differently coloured cultivars exhibiting orange, purple, red and yellow hues were investigated. The impact of HPHT sterilisation was compared with thermal sterilisation based on equivalent microbiological inactivation. The results of this study demonstrated HPHT sterilisation to exert a distinct effect on important chemical reactions in comparison to thermal sterilisation. A comprehensive integration of MS-based metabolomic fingerprinting (HS-SPME-GC-MS) and chemometric tools has been implemented as an untargeted multivariate screening tool to identify differences. In all carrot cultivars, two dominant discriminative quality-related reactions were found: oxidative degradation and the Maillard reaction. Regarding the first reaction, oxidative terpenes, free fatty acids and carotenoids degradation products were detected at higher levels after HPHT sterilisation. Regarding the latter reaction, HPHT sterilisation appeared to suppress the formation of Maillard and Strecker degradation products. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Method for high temperature mercury capture from gas streams

    DOEpatents

    Granite, E.J.; Pennline, H.W.

    2006-04-25

    A process to facilitate mercury extraction from high temperature flue/fuel gas via the use of metal sorbents which capture mercury at ambient and high temperatures. The spent sorbents can be regenerated after exposure to mercury. The metal sorbents can be used as pure metals (or combinations of metals) or dispersed on an inert support to increase surface area per gram of metal sorbent. Iridium and ruthenium are effective for mercury removal from flue and smelter gases. Palladium and platinum are effective for mercury removal from fuel gas (syngas). An iridium-platinum alloy is suitable for metal capture in many industrial effluent gas streams including highly corrosive gas streams.

  5. Heterodyne method for high specificity gas detection.

    NASA Technical Reports Server (NTRS)

    Dimeff, J.; Donaldson, R. W.; Gunter, W. D., Jr.; Jaynes, D. N.; Margozzi, A. P.; Deboo, G. J.; Mcclatchie, E. A.; Williams, K. G.

    1971-01-01

    This paper describes a new technique for measuring trace quantities of gases. The technique involves the use of a reference cell (containing a known amount of the gas being sought) and a sample cell (containing an unknown amount of the same gas) wherein the gas densities are modulated. Light passing through the two cells in sequence is modulated in intensity at the vibrational-rotational lines characteristic of the absorption spectrum for the gas of interest. Since the absorption process is nonlinear, modulating the two absorption cells at two different frequencies gives rise to a heterodyning effect, which in turn introduces sum and difference frequencies in the detected signal. Measuring the ratio of the difference frequency signal for example, to the signal introduced by the reference cell provides a normalized measure of the amount of the gas in the sample cell. The readings produced are thereby independent of source intensity, window transparency, and detector sensitivity. Experimental evaluation of the technique suggests that it should be applicable to a wide range of gases, that it should be able to reject spurious signals due to unwanted gases, and that it should be sensitive to concentrations of the order of 10 to the minus 8th power when used with a sample cell of only 20 cm length.

  6. Apoptosis-inducing activity of high molecular weight fractions of tea extracts.

    PubMed

    Hayakawa, S; Kimura, T; Saeki, K; Koyama, Y; Aoyagi, Y; Noro, T; Nakamura, Y; Isemura, M

    2001-02-01

    High molecular weight fractions of green tea, black tea, oolong tea, and pu-erh tea were found to induce apoptosis in human monoblastic leukemia U937 cells by examination of their ability to inhibit cell proliferation and to induce apoptotic body formation and DNA ladder formation. These tea fractions were also shown to induce apoptosis in stomach cancer MKN-45 cells. In addition to known antitumor-promoting activity of tea high molecular weight fractions, their apoptosis-inducing activity may contribute to cancer chemopreventive effects of tea.

  7. High-Order Compact Difference Scheme for the Numerical Solution of Time Fractional Heat Equations

    PubMed Central

    Karatay, Ibrahim; Bayramoglu, Serife R.

    2014-01-01

    A high-order finite difference scheme is proposed for solving time fractional heat equations. The time fractional derivative is described in the Riemann-Liouville sense. In the proposed scheme a new second-order discretization, which is based on Crank-Nicholson method, is applied for the time fractional part and fourth-order accuracy compact approximation is applied for the second-order space derivative. The spectral stability and the Fourier stability analysis of the difference scheme are shown. Finally a detailed numerical analysis, including tables, figures, and error comparison, is given to demonstrate the theoretical results and high accuracy of the proposed scheme. PMID:24696040

  8. Low or High Fractionation Dose {beta}-Radiotherapy for Pterygium? A Randomized Clinical Trial

    SciTech Connect

    Viani, Gustavo Arruda; De Fendi, Ligia Issa; Fonseca, Ellen Carrara; Stefano, Eduardo Jose

    2012-02-01

    Purpose: Postoperative adjuvant treatment using {beta}-radiotherapy (RT) is a proven technique for reducing the recurrence of pterygium. A randomized trial was conducted to determine whether a low fractionation dose of 2 Gy within 10 fractions would provide local control similar to that after a high fractionation dose of 5 Gy within 7 fractions for surgically resected pterygium. Methods: A randomized trial was conducted in 200 patients (216 pterygia) between February 2006 and July 2007. Only patients with fresh pterygium resected using a bare sclera method and given RT within 3 days were included. Postoperative RT was delivered using a strontium-90 eye applicator. The pterygia were randomly treated using either 5 Gy within 7 fractions (Group 1) or 2 Gy within 10 fractions (Group 2). The local control rate was calculated from the date of surgery. Results: Of the 216 pterygia included, 112 were allocated to Group 1 and 104 to Group 2. The 3-year local control rate for Groups 1 and 2 was 93.8% and 92.3%, respectively (p = .616). A statistically significant difference for cosmetic effect (p = .034), photophobia (p = .02), irritation (p = .001), and scleromalacia (p = .017) was noted in favor of Group 2. Conclusions: No better local control rate for postoperative pterygium was obtained using high-dose fractionation vs. low-dose fractionation. However, a low-dose fractionation schedule produced better cosmetic effects and resulted in fewer symptoms than high-dose fractionation. Moreover, pterygia can be safely treated in terms of local recurrence using RT schedules with a biologic effective dose of 24-52.5 Gy{sub 10.}.

  9. High-dose fractionated radiation therapy for select patients with brain metastases

    SciTech Connect

    Pezner, R.D.; Lipsett, J.A.; Archambeau, J.O.; Fine, R.M.; Moss, W.T.

    1981-08-01

    Four patients with metastases to the brain were treated by high-dose fractionated radiation therapy. In all four cases, a complete response and prolonged disease-free survival could be documented. Unlike the standard therapy for such patients (i.e., craniotomy and postoperative irradiation), high-dose fractionated radiation therapy carries no operative risk and can encompass multiple brain metastases and metastases in deep or critical intracranial sites. The risk of radiotherapy side effects in the brain is discussed.

  10. Shells, holes, worms, high-velocity gas and the z-distribution of gas in galaxies.

    NASA Astrophysics Data System (ADS)

    Rand, R. J.

    The author gives an overview of the current observational understanding of vertically extended gas components in spiral galaxies and the various phenomena which come under such names as shells, holes, worms, and high-velocity gas. For the most part, the focus is on recent high-resolution interferometric studies. The author concentrates on cold gas, and briefly on warm ionized gas, in the Milky Way and a few nearby spirals. Along the way, it is seen how phenomena such as worms and shells may be related to the formation and maintenance of the vertically extended components.

  11. Escape fraction of ionizing photons from high-redshift galaxies in cosmological SPH simulations

    NASA Astrophysics Data System (ADS)

    Yajima, Hidenobu; Choi, Jun-Hwan; Nagamine, Kentaro

    2011-03-01

    Combing the three-dimensional radiative transfer (RT) calculation and cosmological smoothed particle hydrodynamics (SPH) simulations, we study the escape fraction of ionizing photons (fesc) of high-redshift galaxies at z= 3-6. Our simulations cover the halo mass range of Mh= 109-1012 M⊙. We post-process several hundred simulated galaxies with the Authentic Radiative Transfer (ART) code to study the halo mass dependence of fesc. In this paper, we restrict ourselves to the transfer of stellar radiation from local stellar population in each dark matter halo. We find that the average fesc steeply decreases as the halo mass increases, with a large scatter for the lower-mass haloes. The low-mass haloes with Mh˜ 109 M⊙ have large values of fesc (with an average of ˜0.4), whereas the massive haloes with Mh˜ 1011 M⊙ show small values of fesc (with an average of ˜0.07). This is because in our simulations, the massive haloes show more clumpy structure in gas distribution, and the star-forming regions are embedded inside these clumps, making it more difficult for the ionizing photons to escape. On the other hand, in low-mass haloes, there are often conical regions of highly ionized gas due to the shifted location of young star clusters from the centre of dark matter halo, which allows the ionizing photons to escape more easily than in the high-mass haloes. By counting the number of escaped ionizing photons, we show that the star-forming galaxies can ionize the intergalactic medium at z= 3-6. The main contributor to the ionizing photons is the haloes with Mh≲ 1010 M⊙ owing to their high fesc. The large dispersion in fesc suggests that there may be various sizes of H II bubbles around the haloes even with the same mass in the early stages of reionization. We also examine the effect of UV background radiation field on fesc using simple, four different treatments of UV background.

  12. Vacuum Surface Flashover And High Pressure Gas Streamers

    DTIC Science & Technology

    1997-06-01

    Optical Emission Characteristics of Polycrystalline Diamond During Surface Flashover in Vacuum ," 1996 IEEE 1~ International Symposium on... VACUUM SURFACE FLASHOVER AND HIGH PRESSURE GAS STREAMERS J. M. Elizondo, M. L. Krogh, D. Smith, D. Stoltz, and S. N. Wright AlliedSignal Federal...breakdown current traces obtained during high pressure gas breakdown and vacuum surface flashover show similar signatures. The initial

  13. X-ray and Sunyaev-Zel'dovich Effect Measurements of the Gas Mass Fraction in Galaxy Clusters

    NASA Technical Reports Server (NTRS)

    LaRoque, Samuel J.; Bonamente, Massimiliano; Carlstrom, John E.; Joy, Marshall K.; Nagai, Daisuke; Reese, Erik D.; Dawson, Kyle S.

    2006-01-01

    We present gas mass fractions of 38 massive galaxy clusters spanning redshifts from 0.14 to 0.89, derived from Chandra X-ray data and OVRO/BIMA interferometric Sunyaev-Zel' dovich Effect (SZE) measurements. We use three models for the gas distribution: (1) an isothermal Beta-model fit jointly to the X-ray data at radii beyond 100 kpc and to all of the SZE data, (2) a nonisothermal double Beta-model fit jointly to all of the X-ray and SZE data, and (3) an isothermal Beta-model fit only to the SZE spatial data. We show that the simple isothermal model well characterizes the intracluster medium (ICM) outside of the cluster core, and provides consistently good fits to clusters spanning a wide range of morphological properties. The agreement in the results shows that the core can be satisfactorily accounted for by either excluding the core in fits to the X-ray data (the 100 kpc-cut model) or modeling the intracluster gas with a non-isothermal double Beta-model. We find that the SZE is largely insensitive to structure in the core.

  14. X-ray and Sunyaev-Zel'dovich Effect Measurements of the Gas Mass Fraction in Galaxy Clusters

    NASA Technical Reports Server (NTRS)

    LaRoque, Samuel J.; Bonamente, Massimiliano; Carlstrom, John E.; Joy, Marshall K.; Nagai, Daisuke; Reese, Erik D.; Dawson, Kyle S.

    2006-01-01

    We present gas mass fractions of 38 massive galaxy clusters spanning redshifts from 0.14 to 0.89, derived from Chandra X-ray data and OVRO/BIMA interferometric Sunyaev-Zel' dovich Effect (SZE) measurements. We use three models for the gas distribution: (1) an isothermal Beta-model fit jointly to the X-ray data at radii beyond 100 kpc and to all of the SZE data, (2) a nonisothermal double Beta-model fit jointly to all of the X-ray and SZE data, and (3) an isothermal Beta-model fit only to the SZE spatial data. We show that the simple isothermal model well characterizes the intracluster medium (ICM) outside of the cluster core, and provides consistently good fits to clusters spanning a wide range of morphological properties. The agreement in the results shows that the core can be satisfactorily accounted for by either excluding the core in fits to the X-ray data (the 100 kpc-cut model) or modeling the intracluster gas with a non-isothermal double Beta-model. We find that the SZE is largely insensitive to structure in the core.

  15. Acoustic and microwave tests in a cylindrical cavity for acoustic gas thermometry at high temperature

    PubMed Central

    Zhang, K.; Feng, X.J.; Gillis, K.; Moldover, M.; Zhang, J.T.; Lin, H.; Qu, J.F.; Duan, Y.N.

    2016-01-01

    Relative primary acoustic gas thermometry determines the ratios of thermodynamic temperatures from measured ratios of acoustic and microwave resonance frequencies in a gas-filled metal cavity on isotherms of interest. When measured in a cavity with known dimensions, the frequencies of acoustic resonances in a gas determine the speed of sound, which is a known function of the thermodynamic temperature T. Changes in the dimensions of the cavity are measured using the frequencies of the cavity's microwave resonances. We explored techniques and materials for acoustic gas thermometry at high temperatures using a cylindrical cavity with remote acoustic transducers. We used gas-filled ducts as acoustic waveguides to transmit sound between the cavity at high temperatures and the acoustic transducers at room temperature. We measured non-degenerate acoustic modes in a cylindrical cavity in the range 295 K < T < 797 K. The fractional uncertainty of the measured acoustic frequencies increased from 2×10−6 at 295 K to 5×10−6 at 797 K. In addition, we measured the frequencies of several transverse magnetic (TM) microwave resonances up to 1000 K in order to track changes in the cavity's length L and radius R. The fractional standard deviation of the values of L deduced from three TM modes increased from 3×10−6 for T < 600 K to 57×10−6 at 1000 K. We observed similar inconsistencies in a previous study. PMID:26903106

  16. High temperature coatings for gas bearings

    NASA Technical Reports Server (NTRS)

    Murray, S. F.

    1969-01-01

    Aluminum oxide and nickel-chrome bonded chrome carbide coatings enhance the performance of gas bearings at temperatures up to 1400 degrees F. A plasma-sprayed aluminum-oxide coating is applied to the bearing surface and a plasma- sprayed 25 percent nickel-chrome bonded chrome carbide coating is applied to the journal surface.

  17. Comparison of three sequential extraction procedures for arsenic fractionation in highly polluted sites.

    PubMed

    Wan, Xiang; Dong, Haochen; Feng, Liu; Lin, Zhijia; Luo, Qiuchen

    2017-07-01

    Three sequential extraction procedures (SEPs) including Tessier, Rauret, and Shiowatana SEPs, were compared for arsenic fractionation using highly polluted soils. In the definition context of exchangeable, reducible, oxidizable and residual fractions, with similar arsenic recovery and reproducibility, Tessier and Rauret SEPs were comparable to each other, whereas Shiowatana SEP showed higher extraction efficiency in all the first three arsenic fractions, although it might overestimate the reducible arsenic. Pot experiment indicated three SEPs all could provide an estimation of the most bioavailable arsenic fraction, and the application of Shiowatana SEP should be preferred. Accordingly, a case study with Shiowatana SEP for a site near a realgar mine area is conducted. The results show that although arsenic in this area presents predominantly in the stable fractions, the sum of most bioavailable fractions was accounted around 11% of total arsenic, and moreover, about another 10% of the total arsenic, the fourth fraction in Shiowatana SEP is likely to be transferred into bioavailable species under suitable conditions, such as strong acid impact, revealing a real major risk source being formed. The study indicated that Shiowatana should be more suitable for arsenic fractionation to provide valuable information in the framework of risk assessment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. The linear-quadratic model is inappropriate to model high dose per fraction effects in radiosurgery.

    PubMed

    Kirkpatrick, John P; Meyer, Jeffrey J; Marks, Lawrence B

    2008-10-01

    The linear-quadratic (LQ) model is widely used to model the effect of total dose and dose per fraction in conventionally fractionated radiotherapy. Much of the data used to generate the model are obtained in vitro at doses well below those used in radiosurgery. Clinically, the LQ model often underestimates tumor control observed at radiosurgical doses. The underlying mechanisms implied by the LQ model do not reflect the vascular and stromal damage produced at the high doses per fraction encountered in radiosurgery and ignore the impact of radioresistant subpopulations of cells. The appropriate modeling of both tumor control and normal tissue toxicity in radiosurgery requires the application of emerging understanding of molecular-, cellular-, and tissue-level effects of high-dose/fraction-ionizing radiation and the role of cancer stem cells.

  19. Electrophoretic chip for high-fidelity fractionation of double-stranded DNA.

    PubMed

    Sun, Kai; Li, Zheyu; Ueno, Kosei; Juodkazis, Saulius; Noji, Sumihare; Misawa, Hiroaki

    2007-05-01

    We report the high fidelity, on-chip fractionation of selected segments from an electrophoretic flow of separated fragments. dsDNA fragments (10-330 base pairs (bp)) were initially separated using a 6.5 cm long channel with an electric field strength of 150 V/cm. As an example of the fractionation process, a target fragment of 20 bp was selected and extracted from the separation channel. The extraction was confirmed and evaluated by fluorescence imaging. High resolution and extraction fidelity were achieved by introducing new procedures for (i) extraction channel-blocking and (ii) segment transfer with cleaning. These procedures are necessary for the development of a practical, fully automated multitarget fractionation electrophoretic chip. A kind of CCD image processing method was introduced to monitor, control, and evaluate the procedure of fractionation. The resolution limits of the separation and extraction are discussed.

  20. The Dense Gas Fraction in the Central Molecular Zone in the Milky Way

    NASA Astrophysics Data System (ADS)

    Vargas-Salazar, Irene; Battersby, Cara; Walker, Daniel; Zhang, Qizhou; CMZoom

    2017-01-01

    The Central Molecular Zone (CMZ), a large reservoir of dense molecular gas occupying the central 500pc of the Milky Way, is an extreme star-formation environment where the validity of star formation prescriptions can be tested. The star formation rate (SFR) in the CMZ is about an order of magnitude lower than predicted by the currently accepted prescriptions. An international team lead by PIs Battersby and Keto conducted a survey from 2013-2016 called CMZoom using the Submillimeter Array (SMA) to characterize star formation within resolved molecular clouds in this extreme region. One of the main goals of this survey is to further quantify and understand the low SFR found in this region of the Galaxy. Here, we use the CASA software package to run synthetic observations of hydrodynamical simulations of molecular clouds and vary the observation parameters in such a way that we explore the real parameter space that was probed during the survey. The purpose of this is to investigate how the different observational parameters affect the resultant data. Afterwards, we estimate the “dense gas fraction” (DGF) found in regions across the CMZ. This estimate was found by using the interferometric flux from SMA and the single-dish flux from the Bolocam Galactic Plane Survey. We analyzed the effects that different locations of the CMZ had on these approximate DGF. With these simulations and DGF estimates, we are able to generate improved methods to analyze the data from this survey that will help understand star formation in an extreme environment.The SAO REU program is funded in part by the National Science Foundation REU and Department of Defense ASSURE programs under NSF Grant no.1262851, and by the Smithsonian Institution.

  1. Highly ionized gas in the Galactic halo

    NASA Technical Reports Server (NTRS)

    Shull, J. Michael; Slavin, Jonathan D.

    1994-01-01

    We reexamine the values of electron density n(sub e) and gas pressure P/k in the interstellar medium (ISM) of the Galactic halo, as inferred from C IV emission and absorption lines and using current C IV atomic data. In a homogeneous model with 4.7 less than or equal to log T less than or equal to 5.3, the data are consistent with 0.01 less than or equal to n(sub e) less than or equal to 0.02/cu cm and 2200 less than or equal to P/k less than or equal to 3700/cu cm K, a factor of 2-3 higher than advocated by Martin & Bowyer (1990) and comparable to the thermal pressure in the disk. If some of the C IV absorption arises from nonemitting, photoionized gas, then the inferred density and pressure will increase accordingly. The volume filling factor for homogeneous models ranges from 0.5% to 5%. Because of the constraints arising from filling factor and radiated power, most of the C IV must arise from gas near the peak of the cooling curve, at log t less than or equal to 5.6. We relate both emission-line and absorption-line observations to recent models in which turbulent mixing layers and isobarically cooling supernova remnants (SNRs) provide significant amounts of halo gas at approximately 10(exp 5.3) K and process 20-40 solar mass/yr with a power of approximately 10(exp 41) ergs/sec. Since the observed C IV and N V absorption scale heights have been reported to differ, at 4.9 kpc and 1.6 kpc, respectively, we examine inhomogeneous models with different exponential scale heights of T, P, and SN energy input. The ISM may change its character with distance above the Galactic plane, as superbubbles and mixing layers dominate over isolated SNRs as the source of the C IV. For appropiate scale heights, the midplane pressure is twice the homogeneous values quoted above. The O IV lambda 1034 diffuse emission line, which can be used as a temperature diagnostic of the hot gas, is predicted to be comparable in strength to that of C IV lambda 1549 (approximately 6000 photons

  2. The capability of radial basis function to forecast the volume fractions of the annular three-phase flow of gas-oil-water.

    PubMed

    Roshani, G H; Karami, A; Salehizadeh, A; Nazemi, E

    2017-11-01

    The problem of how to precisely measure the volume fractions of oil-gas-water mixtures in a pipeline remains as one of the main challenges in the petroleum industry. This paper reports the capability of Radial Basis Function (RBF) in forecasting the volume fractions in a gas-oil-water multiphase system. Indeed, in the present research, the volume fractions in the annular three-phase flow are measured based on a dual energy metering system including the (152)Eu and (137)Cs and one NaI detector, and then modeled by a RBF model. Since the summation of volume fractions are constant (equal to 100%), therefore it is enough for the RBF model to forecast only two volume fractions. In this investigation, three RBF models are employed. The first model is used to forecast the oil and water volume fractions. The next one is utilized to forecast the water and gas volume fractions, and the last one to forecast the gas and oil volume fractions. In the next stage, the numerical data obtained from MCNP-X code must be introduced to the RBF models. Then, the average errors of these three models are calculated and compared. The model which has the least error is picked up as the best predictive model. Based on the results, the best RBF model, forecasts the oil and water volume fractions with the mean relative error of less than 0.5%, which indicates that the RBF model introduced in this study ensures an effective enough mechanism to forecast the results. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Fast High Capacity Annular Gas Puff Valve Design Concept

    NASA Astrophysics Data System (ADS)

    Ruden, Edward

    2000-10-01

    A fast opening gas valve design concept is presented that can theoretically inject a few grams of D2 gas radially outward into a coaxial annular vacuum region with a radius of about 10 cm in less that 100 μ s. The concept employs a single turn 20-30 T pulsed magnetic field coil that axially accelerates an Mg alloy ring, which seals a gas plenum, to high velocity, releasing the gas. Both coil and ring are profiled to minimize stress in the ring. Such a device could be used to supply the initial gas load for a proposed 5 MJ Dense Plasma Focus driven by AFRL's Shiva Star Capacitor bank. The intent here is keep the vacuum current feed insulator under high vacuum during the discharge to avoid surface breakdown. Alternatively, a high energy rep ratable plasma flow opening switch could be supplied with such a valve. This work is funded by the USAF.

  4. Gas adsorption and desorption effects on high pressure small volume cylinders and their relevance to atmospheric trace gas analysis

    NASA Astrophysics Data System (ADS)

    Satar, Ece; Nyfeler, Peter; Pascale, Céline; Niederhauser, Bernhard; Leuenberger, Markus

    2017-04-01

    Long term atmospheric monitoring of trace gases requires great attention to precision and accuracy of the measurement setups. For globally integrated and well established greenhouse gas observation networks, the World Meteorological Organization (WMO) has set recommended compatibility goals within the framework of its Global Atmosphere Watch (GAW) Programme [1]. To achieve these challenging limits, the measurement systems are regularly calibrated with standard gases of known composition. Therefore, the stability of the primary and secondary gas standards over time is an essential issue. Past studies have explained the small instabilities in high pressure standard gas cylinders through leakage, diffusion, regulator effects, gravimetric fractionation and surface processes [2, 3]. The latter include adsorption/desorption, which are functions of temperature, pressure and surface properties. For high pressure standard gas mixtures used in atmospheric trace gas analysis, there exists only a limited amount of data and few attempts to quantify the surface processes [4, 5]. Specifically, we have designed a high pressure measurement chamber to investigate trace gases and their affinity for adsorption on different surfaces over various temperature and pressure ranges. Here, we focus on measurements of CO2, CH4 and CO using a cavity ring down spectroscopy analyzer and quantify the concentration changes due to adsorption/desorption. In this study, the first results from these prototype cylinders of steel and aluminum will be presented. References [1] World Meteorological Organization (WMO), Global Atmosphere Watch.(GAW): Report No. 229, 18th WMO/IAEA Meeting on Carbon Dioxide, Other Greenhouse Gases and Related Tracers Measurement Techniques (GGMT-2015), 2016. [2] Keeling, R. F., Manning, A. C., Paplawsky, W. J., and Cox, A. C.: On the long-term stability of reference gases for atmospheric O2 /N2 and CO2 measurements, Tellus B, 59, 10.3402/tellusb.v59i1.16964, 2007. [3

  5. Assessing changes in stratospheric mean age of air and fractional release using historical trace gas observations

    NASA Astrophysics Data System (ADS)

    Laube, Johannes; Bönisch, Harald; Engel, Andreas; Röckmann, Thomas; Sturges, William

    2014-05-01

    Large-scale stratospheric transport is pre-dominantly governed by the Brewer-Dobson circulation. Due to climatic change a long-term acceleration of this residual stratospheric circulation has been proposed (e.g. Austin et al.,2006). Observational evidence has revealed indications for temporary changes (e.g. Bönisch et al., 2011) but a confirmation of a significant long-term trend is missing so far (e.g. Engel et al., 2009). A different aspect is a possible long-term change in the break-down of chemically important species such as chlorofluorocarbons as proposed by Butchart et al. 2001. Recent studies show significant differences adding up to more than 20 % in the chlorine released from such compounds (Newman et al., 2007; Laube et al., 2013). We here use a data set of three long-lived trace gases, namely SF6, CF2Cl2, and N2O, as measured in whole-air samples collected during balloon and aircraft flights between 1975 and 2011, to assess changes in stratospheric transport and chemistry. For this purpose we utilise the mean stratospheric transit times (or mean ages of air) in combination with a measure of the chemical decomposition (i.e. fractional release factors). We also evaluate the influence of different trend correction methods on these quantities and explore their variability with latitude, altitude, and season. References Austin, J. & Li, F.: On the relationship between the strength of the Brewer-Dobson circulation and the age of stratospheric air, Geophys. Res. Lett., 33, L17807, 2006. Bönisch, H., Engel, A., Birner, Th., Hoor, P., Tarasick, D. W., and Ray, E. A.: On the structural changes in the Brewer-Dobson circulation after 2000, Atmos. Chem. Phys., 11, 3937-3948, 2011. Butchart, N. & Scaife, A. A. Removal of chlorofluorocarbons by increased mass exchange between the stratosphere and troposphere in a changing climate. Nature, 410, 799-802, 2001. Engel, A., Möbius, T., Bönisch, H., Schmidt, U., Heinz, R., Levin, I., Atlas, E., Aoki, S., Nakazawa, T

  6. Preparation of Highly Immunogenic Ribosomal Fractions of Mycobacterium tuberculosis by Use of Sodium Dodecyl Sulfate

    PubMed Central

    Youmans, Anne S.; Youmans, Guy P.

    1966-01-01

    Youmans, Anne S. (Northwestern University Medical School, Chicago, Ill.), and Guy P. Youmans. Preparation of highly immunogenic ribosomal fractions of Mycobacterium tuberculosis by use of sodium dodecyl sulfate. J. Bacteriol. 91:2139–2145. 1966.—Ribosomal fractions of Mycobacterium tuberculosis, strain H37Ra, were prepared by treatment of the intracellular particulate fraction with 0.25 or 0.5% sodium dodecylsulfate (SDS) followed by centrifugation at 144,700 × g for 3 hr. This procedure has greatly simplified the preparation of ribosomal fractions and has given fractions composed of approximately 50% ribonucleic acid (RNA) and 15 to 20% protein. When incorporated into Freund's incomplete adjuvant and injected intraperitoneally into CF-1 mice, the SDS ribosomal fractions were more immunogenic than the particulate fractions from which they were prepared. They were as much as 100 times more immunogenic than ribosomal fractions prepared by differential centrifugation, 1 μg (dry weight) per mouse being sufficient for the induction of some immunity. However, none of these ribosomal preparations, in comparable doses, was as immunogenic as the living cells from which they were prepared. It was also shown that the addition of 10−4m MgCl2 to the final diluent increased immunogenic activity, whereas larger concentrations (10−3m) reduced immunogenic activity. Preparation of the ribosomal fraction from ruptured cells in one continuous process during the course of 1 day increased the activity. Two-week-old H37Ra cells contained more RNA and were more immunogenic than the older cultures which have been used in the past. PMID:4957609

  7. The contribution of gas-phase reactions to the nitroarene fraction of molecular weight 247 present in carbon particles sampled in an urban area of Northern Italy

    NASA Astrophysics Data System (ADS)

    Ciccioli, Paolo; Cecinato, Angelo; Cabella, Renato; Brancaleoni, Enzo; Buttini, Patrizia

    The formation of 2-nitrofluoranthene and 2-nitropyrene by gas-phase atmospheric reactions has been investigated by analysing the nitroarene fraction with molecular weight 247 extracted from 34 high-volume samples collected during two different monitoring campaigns held in the centre of Milan. 2-Nitrofluoranthene, 2-nitropyrene and 1-nitropyrene were the only nitroarenes detected. The ratios 2-nitrofluoranthene/1-nitropyrene and 2-nitrofluoranthene/2-nitropyrene combined with the day/night variations of various photochemical indicators have been used to assess the relative contribution of different reactions leading to the formation of 2-nitroarenes with MW 247 in carbon particles. Daytime OH radical-initiated reactions were found to be mainly responsible for their formation but evidence was collected of nightime formation.

  8. Characterizing the correlations between local phase fractions of gas-liquid two-phase flow with wire-mesh sensor.

    PubMed

    Tan, C; Liu, W L; Dong, F

    2016-06-28

    Understanding of flow patterns and their transitions is significant to uncover the flow mechanics of two-phase flow. The local phase distribution and its fluctuations contain rich information regarding the flow structures. A wire-mesh sensor (WMS) was used to study the local phase fluctuations of horizontal gas-liquid two-phase flow, which was verified through comparing the reconstructed three-dimensional flow structure with photographs taken during the experiments. Each crossing point of the WMS is treated as a node, so the measurement on each node is the phase fraction in this local area. An undirected and unweighted flow pattern network was established based on connections that are formed by cross-correlating the time series of each node under different flow patterns. The structure of the flow pattern network reveals the relationship of the phase fluctuations at each node during flow pattern transition, which is then quantified by introducing the topological index of the complex network. The proposed analysis method using the WMS not only provides three-dimensional visualizations of the gas-liquid two-phase flow, but is also a thorough analysis for the structure of flow patterns and the characteristics of flow pattern transition. This article is part of the themed issue 'Supersensing through industrial process tomography'.

  9. A Satellite Formation Due to A Giant Impact: The Effect of the Protoplanet Mass and Its Composition on the Disk Gas Fraction

    NASA Astrophysics Data System (ADS)

    Nakajima, M.; Genda, H.; Asphaug, E. I.; Ida, S.

    2010-12-01

    It has been thought that the Moon is formed by a giant impact in the late stage of the Earth formation. The impact generates a debris disk around the earth, from which the Moon is accreted. This type of satellite formation is believed to be common in the solar and extra solar systems, such as Pluto and its moon, Charon. Recent study has revealed that the initial gas mass fraction in an impact-generated disk can highly affect the satellite formation process. It also means that a satellite mass depends on the initial disk gas ratio. Machida and Abe (2004) have shown that the higher disk gas ratio creates smaller satellite mass. They have also found out that if evaporation rate exceeds 70%, no satellite can be formed from the disk since solid/liquid materials in the disk fall into the Earth or escape before the disk cooling. Wada et al. (2006) have suggested that strong shocks occur in a gas rich disk, which causes most of the disk material falls into the earth within a few days. Thus, initial disk gas ratio must be taken into account in order to understand the satellite formation process, however, its effect has not been considered carefully yet. In our work, we have investigated the disk gas ratio as a function of protoplanet mass and its material, based on the idea that impact energy and the latent heat of disk material basically define the disk gas ratio. We have performed giant impact simulations of water-icy and rocky protoplanets using Smoothed Particle Hydrodynamics (SPH) method. ANEOS and SESAME equation of states are used. As a result, the disk evaporation is negligible in a Pluto-Chaon mass-size impact, but for an Earth-Moon size, the disk evaporation rate of the water-icy protoplanet can exceed 70%, whereas that of rocky one is about 10-30%. For a 5 Earth mass size system, most of the disk material evaporates in both icy and rocky protoplanet impacts. The result suggests that protoplanet mass and its material also affect the satellite mass. In our

  10. Development of high pressure gas cells at ISIS

    NASA Astrophysics Data System (ADS)

    Kirichek, O.; Done, R.; Goodway, C. M.; Kibble, M. G.; Evans, B.; Bowden, Z. A.

    2012-02-01

    High-pressure research is one of the fastest-growing areas of natural science, and one that attracts as diverse communities as those of physics, bio-physics, chemistry, materials science and earth science. In condensed matter physics there are a number of highly topical areas, such as quantum criticality, pressure-induced superconductivity or non-Fermi liquid behaviour, where pressure is a fundamental parameter. Reliable, safe and user-friendly high pressure gas handling systems with gas pressures up to 1GPa should make a significant impact on the range of science possible. The ISIS facility is participating in the NMI3 FP7 sample environment project supported by the European Commission which includes high pressure gas cell development. In this paper the progress in designing, manufacturing and testing a new generation of high pressure gas cells for neutron scattering experiments is discussed.

  11. High quality fuel gas from biomass pyrolysis with calcium oxide.

    PubMed

    Zhao, Baofeng; Zhang, Xiaodong; Chen, Lei; Sun, Laizhi; Si, Hongyu; Chen, Guanyi

    2014-03-01

    The removal of CO2 and tar in fuel gas produced by biomass thermal conversion has aroused more attention due to their adverse effects on the subsequent fuel gas application. High quality fuel gas production from sawdust pyrolysis with CaO was studied in this paper. The results of pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) experiments indicate that the mass ratio of CaO to sawdust (Ca/S) remarkably affects the behavior of sawdust pyrolysis. On the basis of Py-GC/MS results, one system of a moving bed pyrolyzer coupled with a fluid bed combustor has been developed to produce high quality fuel gas. The lower heating value (LHV) of the fuel gas was above 16MJ/Nm(3) and the content of tar was under 50mg/Nm(3), which is suitable for gas turbine application to generate electricity and heat. Therefore, this technology may be a promising route to achieve high quality fuel gas for biomass utilization. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. High pressure gas pipeline under the influence of radiation

    NASA Astrophysics Data System (ADS)

    Ilic, Marko N.; Ilic, Gradimir S.; Stefanovic, Velimir P.; Pavlovic, Sasa R.; Bojic, Milorad L. j.

    2012-11-01

    This paper presents one of the possible hazardous situations during transportation of gas through the international pipeline. It describes case when at high pressure gas pipeline, due to mechanical or chemical effect, the crack and gas leakage appears and gas is somehow triggered to combusting. As a consequence of heat impingement on the pipe surface will be, change of material properties (decreasing of strength) at high temperatures. In order to avoid greater rapture a reasonable pressure relief rate needs to be applied. Standards in this particular domain of depressurizing procedure are not so exact (DIN EN ISO 23251; API 521). The main part of the work consists of two calculations. First is the numerical simulation of heat radiation of combustible gas which affects the pipeline, done by software FLUENT, and second in Matlab. There are also given conclusions according to achieved results.

  13. Fractionation of the reference inoculum of epizootic rabbit enteropathy in discontinuous sucrose gradient identifies aetiological agents in high density fractions.

    PubMed

    Szalo, I M; Lassence, C; Licois, D; Coudert, P; Poulipoulis, A; Vindevogel, H; Marlier, D

    2007-05-01

    Epizootic rabbit enteropathy (ERE) is a major cause of economic loss in intensive rabbit production. Since its first recognition in 1997, much work has been done to determine the pathogenic mechanisms of the disease and to identify the aetiological agent(s). Unfortunately, the quest for aetiology has only met with limited success despite the ability to reproduce the syndrome by inoculation of intestinal contents from field cases. These intestinal inocula contain a huge number of microorganisms which could all be involved in the aetiology of ERE. To decrease the number of putative agents, the French reference inoculum TEC3 was fractionated on a discontinuous sucrose gradient so that seven fractions (supernatant, 10%, 20%, 30%, 40%, 50% and pellet) were obtained. Specific-pathogen-free rabbits were inoculated with three out of these seven fractions (supernatant, 30%, and pellet). The objectives were: (1) to characterise the seven fractions by bacteriological examination; (2) to verify whether the aetiological agent was present in the fractions by inoculation of rabbits; (3) to assign the aetiological agent of ERE to a morphological group of pathogens; (4) to identify a fraction which could replace the reference inoculum TEC3 in applications such as cell cultures or egg inoculation. The results strongly suggest that ERE is a bacterial disease and does not have a viral or parasitic aetiology.

  14. Experimental investigation on the carbon isotope fractionation of methane during gas migration by diffusion through sedimentary rocks at elevated temperature and pressure

    NASA Astrophysics Data System (ADS)

    Zhang, Tongwei; Krooss, Bernhard M.

    2001-08-01

    Molecular transport (diffusion) of methane in water-saturated sedimentary rocks results in carbon isotope fractionation. In order to quantify the diffusive isotope fractionation effect and its dependence on total organic carbon (TOC) content, experimental measurements have been performed on three natural shale samples with TOC values ranging from 0.3 to 5.74%. The experiments were conducted at 90°C and fluid pressures of 9 MPa (90 bar). Based on the instantaneous and cumulative composition of the diffused methane, effective diffusion coefficients of the 12CH4 and 13CH4 species, respectively, have been calculated. Compared with the carbon isotopic composition of the source methane (δ13C1 = -39.1‰), a significant depletion of the heavier carbon isotope (13C) in the diffused methane was observed for all three shales. The degree of depletion is highest during the initial non-steady state of the diffusion process. It then gradually decreases and reaches a constant difference (Δ δ = δ13Cdiff -δ13Csource) when approaching the steady-state. The degree of the isotopic fractionation of methane due to molecular diffusion increases with the TOC content of the shales. The carbon isotope fractionation of methane during molecular migration results practically exclusively from differences in molecular mobility (effective diffusion coefficients) of the 12CH4 and 13CH4 entities. No measurable solubility fractionation was observed. The experimental isotope-specific diffusion data were used in two hypothetical scenarios to illustrate the extent of isotopic fractionation to be expected as a result of molecular transport in geological systems with shales of different TOC contents. The first scenario considers the progression of a diffusion front from a constant source (gas reservoir) into a homogeneous ;semi-infinite; shale caprock over a period of 10 Ma. In the second example, gas diffusion across a 100 m caprock sequence is analyzed in terms of absolute quantities and isotope

  15. 9. Photocopy of engineering drawing. LC 17 HIGH PRESSURE GAS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. Photocopy of engineering drawing. LC 17 HIGH PRESSURE GAS INSTALLATION: SITE & GRADING PLAN, APRIL 1969. - Cape Canaveral Air Station, Launch Complex 17, Facility 28419, East end of Lighthouse Road, Cape Canaveral, Brevard County, FL

  16. The highly ionized, high-velocity gas in NGC 6231

    NASA Astrophysics Data System (ADS)

    Massa, Derck

    2017-02-01

    It is well known that clusters of massive stars are influenced by the presence of strong winds, that they are sources of diffuse X-rays from shocked gas, and that this gas can be vented into the surrounding region or the halo through the champagne effect. However, the details of how these different environments interact and evolve are far from complete. This paper attributes the broad C IVλλ1500 absorption features (extending to -1900 km s-1) that are seen in the spectra of main sequence B stars in NGC 6231 to gas in the cluster environment and not the B stars themselves. It is shown that the presence of a WC star, WR 79, in the cluster makes this gas detectable because its wind enriches the cluster gas with carbon. Given the available data, it is not clear whether the absorbing gas is simply the far wind of WR 79 or a collective cluster wind enriched by carbon from the wind of WR 79. If it is simply due to the wind, then this wind must flow, unimpeded for more than 2 pc, suggesting that the inner region of the cluster is nearly devoid of obstructing material. If it is actually a collective wind from the cluster, then we could be witnessing an important stage of galactic feedback. In either case, the observations provide a unique and significant piece to the puzzle of how massive, open clusters evolve.

  17. Ionization chamber for measurements of high-level tritium gas

    SciTech Connect

    Carstens, D.H.W.; David, W.R.

    1980-01-01

    The construction and calibration of a simple ionization-chamber apparatus for measurement of high level tritium gas is described. The apparatus uses an easily constructed but rugged chamber containing the unknown gas and an inexpensive digital multimeter for measuring the ion current. The equipment after calibration is suitable for measuring 0.01 to 100% tritium gas in hydrogen-helium mixes with an accuracy of a few percent. At both the high and low limits of measurements deviations from the predicted theoretical current are observed. These are briefly discussed.

  18. High pressure gas spheres for neutron and photon experiments

    NASA Astrophysics Data System (ADS)

    Rupp, G.; Petrich, D.; Käppeler, F.; Kaltenbaek, J.; Leugers, B.; Reifarth, R.

    2009-09-01

    High pressure gas spheres have been designed and successfully used in several nuclear physics experiments on noble gases. The pros and cons of this solution are the simple design and the high reliability versus the fact that the density is limited to 40-60% of liquid or solid gas samples. Originally produced for neutron capture studies at keV energies, the comparably small mass of the gas spheres were an important advantage, which turned out to be of relevance for other applications as well. The construction, performance, and operation of the spheres are described and examples for their use are presented.

  19. Ethylene Trace-gas Techniques for High-speed Flows

    NASA Technical Reports Server (NTRS)

    Davis, David O.; Reichert, Bruce A.

    1994-01-01

    Three applications of the ethylene trace-gas technique to high-speed flows are described: flow-field tracking, air-to-air mixing, and bleed mass-flow measurement. The technique involves injecting a non-reacting gas (ethylene) into the flow field and measuring the concentration distribution in a downstream plane. From the distributions, information about flow development, mixing, and mass-flow rates can be dtermined. The trace-gas apparatus and special considerations for use in high-speed flow are discussed. A description of each application, including uncertainty estimates is followed by a demonstrative example.

  20. Pulse plasma carburizing and high pressure gas quenching -- Industrial applications

    SciTech Connect

    Preisser, F.; Schnatbaum, F.

    1995-12-31

    Pulse plasma carburizing with high pressure gas quenching up to 20 bar is the newly developed case hardening process now available in production size equipment. The first part of results demonstrates the tremendous potential of high pressure gas quenching for successful hardening of case hardening steels. The second part opens a window to glance at the pulse plasma carburizing of complex shaped parts. Both processes improve economical data and performance of carburizing processes.

  1. Effect of Gas Pores on Mechanical Properties of High-Pressure Die-Casting AM50 Magnesium Alloy.

    PubMed

    Jiang, Wei; Cao, Zhanyi; Liu, Liping; Jiang, Bo

    2016-08-01

    High-pressure die-casting (HPDC) AM50 tensile specimens were used to investigate characteristics of gas pores and its effect on mechanical properties of HPDC AM50 magnesium alloy. Combining microstructure morphology gained from optical microscopy, scanning electron microscopy (SEM), and three-dimensional (3D) reconstruction with the experimental data from uniaxial tensile testing, we pursued the relationship between gas pores and the mechanical properties of HPDC AM50 Mg alloy. Results indicate that comparing with 3D reconstruction models, 2D images like optical metallography images and SEM images have one-sidedness. Furthermore, the size and maximum areal fraction of gas pores have negative effects on the mechanical properties of HPDC AM50 Mg alloy. With increase of the maximum size of gas pores in the specimen, the ultimate tensile strength (UTS) and elongation decrease. In addition, with the maximum areal fraction becoming larger, both the UTS and elongation decrease linearly.

  2. Magma dynamics at mid-ocean ridges by noble gas kinetic fractionation: Assessment of magmatic ascent rates

    NASA Astrophysics Data System (ADS)

    Paonita, A.; Martelli, M.

    2006-01-01

    Despite its impact in understanding oceanic crust formation and eruptive styles of related volcanism, magma dynamics at mid-ocean ridges are poorly known. Here, we propose a new method to assess ascent rates of mid-ocean ridge basalt (MORB) magmas, as well as their pre- and sin-eruptive dynamics. It is based on the idea that a rising magma can reach a variable degree of both CO2 supersaturation in melt and kinetic fractionation among noble gases in vesicles in relation to its ascent rate through the crust. To quantify the relationship, we have used a model of multicomponent bubble growth in MORB melts, developed by extending the single-component model of Proussevitch and Sahagian [A.A. Proussevitch, D.L. Sahagian, Dynamics and energetics of bubble growth in magmas: analytical formulation and numerical modeling, J. Geophys. Res. 103 (1998), 18223-18251.] to CO2-He-Ar gas mixtures. After proper parameterization, we have applied it to published suites of data having the required features (glasses from Pito Seamount and mid-Atlantic ridges). Our results highlight that the investigated MORB magmas display very different ranges of ascent rates: slow rises of popping rock forming-magmas that cross the crust (0.01-0.5 m/s), slightly faster rates of energetic effusions (0.1-1 m/s), up to rates of 1-10 m/s which fall on the edge between lava effusion and Hawaiian activity. Inside a single plumbing system, very dissimilar magma dynamics highlight the large differences in compressive stress of the oceanic crust on a small scale. Constraints on how the systems of ridges work, as well as the characteristics of the magmatic source, can also be obtained. Our model shows how measurements of both the dissolved gas concentration in melt and the volatile composition of vesicles in the same sample are crucial in recognizing the kinetic effects and definitively assessing magma dynamics. An effort should be made to correctly set the studied samples in the sequence of volcanic submarine

  3. A Novel Approach to Constrain the Escape Fraction and Dust Content at High Redshift Using the Cosmic Infrared Background Fractional Anisotropy

    NASA Astrophysics Data System (ADS)

    Fernandez, Elizabeth R.; Dole, Herve; Iliev, Ilian T.

    2013-02-01

    The Cosmic Infrared Background (CIB) provides an opportunity to constrain many properties of the high-redshift (z > 6) stellar population as a whole. This background, specifically from 1 to 200 μm, should contain information about the era of reionization and the stars that are responsible for these ionizing photons. In this paper, we look at the fractional anisotropy (δI/I) of this high-redshift population, where δI is the ratio of the magnitude of the fluctuations and I is the mean intensity. We show that this can be used to constrain the escape fraction of the population as a whole, because the magnitude of the fluctuations of the CIB depends on the escape fraction, while the mean intensity does not. This results in lower values of the escape fraction producing higher values of the fractional anisotropy. This difference is predicted to be larger at longer wavelength bands (above 10 μm), albeit it is also much harder to observe in that range. We show that the fractional anisotropy can also be used to separate a dusty from a dust-free population. Finally, we discuss the constraints provided by current observations on the CIB fractional anisotropy.

  4. Trends in high temperature gas turbine materials

    NASA Technical Reports Server (NTRS)

    Grisaffe, S. J.; Dreshfield, R. L.

    1981-01-01

    High performance - high technology materials are among the technologies that are required to allow the fruition of such improvements. Materials trends in hot section components are reviewed, and materials for future use are identified. For combustors, airfoils, and disks, a common trend of using multiple material construction to permit advances in technology is identified.

  5. Identification of interactions in fractional-order systems with high dimensions

    SciTech Connect

    Ji, Xiaoxi; Wu, Yu; Sheng, Wenbo; Lin, Wei

    2014-06-15

    This article proposes an approach to identify fractional-order systems with sparse interaction structures and high dimensions when observation data are supposed to be experimentally available. This approach includes two steps: first, it is to estimate the value of the fractional order by taking into account the solution properties of fractional-order systems; second, it is to identify the interaction coefficients among the system variables by employing the compressed sensing technique. An error analysis is provided analytically for this approach and a further improved approach is also proposed. Moreover, the applicability of the proposed approach is fully illustrated by two examples: one is to estimate the mutual interactions in a complex dynamical network described by fractional-order systems, and the other is to identify a high fractional-order and homogeneous sequential differential equation, which is frequently used to describe viscoelastic phenomena. All the results demonstrate the feasibility of figuring out the system mechanisms behind the data experimentally observed in physical or biological systems with viscoelastic evolution characters.

  6. High reflected cubic cavity as long path absorption cell for infrared gas sensing

    NASA Astrophysics Data System (ADS)

    Yu, Jia; Gao, Qiang; Zhang, Zhiguo

    2014-10-01

    One direct and efficient method to improve the sensitivity of infrared gas sensors is to increase the optical path length of gas cells according to Beer-Lambert Law. In this paper, cubic shaped cavities with high reflected inner coating as novel long path absorption cells for infrared gas sensing were developed. The effective optical path length (EOPL) for a single cubic cavity and tandem cubic cavities were investigated based on Tunable Diode Laser Absorption Spectroscopy (TDLAS) measuring oxygen P11 line at 763 nm. The law of EOPL of a diffuse cubic cavity in relation with the reflectivity of the coating, the port fraction and side length of the cavity was obtained. Experimental results manifested an increase of EOPL for tandem diffuse cubic cavities as the decrease of port fraction of the connecting aperture f', and the EOPL equaled to the sum of that of two single cubic cavities at f'<0.01. The EOPL spectra at infrared wavelength range for different inner coatings including high diffuse coatings and high reflected metallic thin film coatings were deduced.

  7. Vegetation Fraction Mapping with High Resolution Multispectral Data in the Texas High Plains

    NASA Astrophysics Data System (ADS)

    Oshaughnessy, S. A.; Gowda, P. H.; Basu, S.; Colaizzi, P. D.; Howell, T. A.; Schulthess, U.

    2010-12-01

    Land surface models use vegetation fraction to more accurately partition latent, sensible and soil heat fluxes from a partially vegetated surface as it affects energy and moisture exchanges between the earth’s surface and atmosphere. In recent years, there is interest to integrate vegetation fraction data into intelligent irrigation scheduling systems to avoid false positive signals to irrigate. Remote sensing can facilitate the collection of vegetation fraction information on individual fields over large areas in a timely and cost-effective manner. In this study, we developed and evaluated a set of vegetation fraction models using least square regression and artificial neural network (ANN) techniques using RapidEye satellite data (6.5 m spatial resolution and on-demand temporal resolution). Four images were acquired during the 2010 summer growing season, covering bare soil to full crop cover conditions, over the USDA-ARS-Conservation and Production Research Laboratory in Bushland, Texas [350 11' N, 1020 06' W; 1,170 m elevation MSL]. Spectral signatures were extracted from 25 ground truth locations with geographic coordinates. Vegetation fraction information was derived from digital photos taken at the time of image acquisition using a supervised classification technique. Comparison of performance statistics indicate that ANN performed slightly better than least square regression models.

  8. A Radio-to-mm Census of Star-forming Galaxies in Protocluster 4C23.56 at Z = 2.5: Gas Mass and Its Fraction Revealed with ALMA

    NASA Astrophysics Data System (ADS)

    Lee, Minju M.; Tanaka, Ichi; Kawabe, Ryohei; Kohno, Kotaro; Kodama, Tadayuki; Kajisawa, Masaru; Yun, Min S.; Nakanishi, Kouichiro; Iono, Daisuke; Tamura, Yoichi; Hatsukade, Bunyo; Umehata, Hideki; Saito, Toshiki; Izumi, Takuma; Aretxaga, Itziar; Tadaki, Ken-ichi; Zeballos, Milagros; Ikarashi, Soh; Wilson, Grant W.; Hughes, David H.; Ivison, R. J.

    2017-06-01

    We investigate gas contents of star-forming galaxies associated with protocluster 4C23.56 at z = 2.49 by using the redshifted CO (3-2) and 1.1 mm dust continuum with the Atacama Large Millimeter/submillimeter Array. The observations unveil seven CO detections out of 22 targeted Hα emitters (HAEs) and four out of 19 in 1.1 mm dust continuum. They have high stellar mass ({M}\\star > 4× {10}10 M ⊙) and exhibit a specific star-formation rate typical of main-sequence star-forming galaxies at z˜ 2.5. Different gas-mass estimators from CO (3-2) and 1.1 mm yield consistent values for simultaneous detections. The gas mass ({M}{gas}) and gas fraction ({f}{gas}) are comparable to those of field galaxies, with {M}{gas}=[0.3,1.8]× {10}11× ({α }{CO}/(4.36× A(Z))) {M}⊙ , where {α }{CO} is the CO-to-H2 conversion factor and A(Z) is the additional correction factor for the metallicity dependence of {α }{CO}, and < {f}{gas}> =0.53+/- 0.07 from CO (3-2). Our measurements place a constraint on the cosmic gas density of high-z protoclusters, indicating that the protocluster is characterized by a gas density higher than that of the general fields by an order of magnitude. We found ρ ({H}2)˜ 5× {10}9 {M}⊙ {{Mpc}}-3 with the CO(3-2) detections. The five ALMA CO detections occur in the region of highest galaxy surface density, where the density positively correlates with global star-forming efficiency (SFE) and stellar mass. Such correlations possibly indicate a critical role of the environment on early galaxy evolution at high-z protoclusters, though future observations are necessary for confirmation.

  9. Characterization of pinto bean high-starch fraction after air classification and extrustion

    USDA-ARS?s Scientific Manuscript database

    The properties of three bean flours (whole, high-starch fraction, and extruded) were studied to determine their potential applications. Significant differences in moisture, protein, resistant starch, total starch, lipids, ash, phytic acid, amino acid content, and fatty acid profile were observed amo...

  10. Improvement of Bubble Model in High Void Fraction for Cavitating Flow Simulations

    NASA Astrophysics Data System (ADS)

    Tsurumi, Nobuo; Tamura, Yoshiaki; Matsumoto, Yoichiro

    One of the cavitation models for cavitating flow simulations is the bubble dynamics based method (bubble model). In a typical bubble dynamics based method, the Rayleigh-Plesset equation is solved for determining the volumetric motion of a bubble. It is derived for a single bubble in uniform fluid, and thus, is not adequate for a bubble in high void fraction fluid. Therefore, in the existing bubble dynamics based model, high void fraction fluid has not been treated as far as utilizing the Rayleigh-Plesset equation is concerned. In this paper, a bubble dynamics model treating high void fraction region is proposed. The present model has a threshold between low and high void fraction. Below the threshold, Rayleigh-Plesset equation is solved. Above the threshold, the second derivative of temporal difference of a bubble radius is set to be zero when the bubble is expanding, and Rayleigh-Plesset equation is again solved when the bubble is shrinking. For computational example, flow around Clark-Y11.7% and NACA0015 is calculated for validation of this approach and compared with experiment and the old bubble dynamics based method.

  11. Microbial sulfate reduction rates and sulfur and oxygen isotope fractionations at oil and gas seeps in deepwater Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Aharon, Paul; Fu, Baoshun

    2000-01-01

    Sulfate reduction and anaerobic methane oxidation are the dominant microbial processes occurring in hydrate-bearing sediments at bathyal depths in the Gulf of Mexico where crude oil and methane are advecting through fault conduits to the seafloor. The oil and gas seeps are typically overlain by chemosynthetic communities consisting of thiotrophic bacterial mats (Beggiatoa spp.) and methanotrophic mussels (Bathymodiolus spp.), respectively. Cores were recovered with a manned submersible from fine-grained sediments containing dispersed gas hydrates at the threshold of stability. Estimated sulfate reduction rates are variable but generally are substantially higher in crude oil seeps (up to 50 times) and methane seeps (up to 600 times) relative to a non-seep reference sediment (0.0043 μmol SO 42- cm -3 day -1). Sulfur and oxygen isotope fractionation factors are highest in the reference sediment (α S = 1.027; α O = 1.015) but substantially lower in the seep sediments (α S = 1.018 to 1.009; α O = 1.006 to 1.002) and are controlled primarily by kinetic factors related to sulfate reduction rates. Kinetic effects also control the δ 34S/δ 18O ratios such that slow microbial rates yield low ratios whereas faster rates yield progressively higher ratios. The seep data contradict previous claims that δ 34S/δ 18O ratios are diagnostic of either microbial sulfate reduction at a fixed δ 34S/δ 18O ratio of 4/1 or lower ratios caused by SO 4-H 2O equilibration at ambient temperatures. The new results offer a better understanding of methane removal via anaerobic oxidation in the sulfate reduction zone of hydrate-bearing sediments and have significant implications regarding the origin and geochemical history of sedimentary sulfate reconstructed on the basis of δ 34S and δ 18O compositions.

  12. Gas Fraction and Depletion Time of Massive Star-forming Galaxies at z ~ 3.2: No Change in Global Star Formation Process out to z > 3

    NASA Astrophysics Data System (ADS)

    Schinnerer, E.; Groves, B.; Sargent, M. T.; Karim, A.; Oesch, P. A.; Magnelli, B.; LeFevre, O.; Tasca, L.; Civano, F.; Cassata, P.; Smolčić, V.

    2016-12-01

    The observed evolution of the gas fraction and its associated depletion time in main-sequence (MS) galaxies provides insights on how star formation proceeds over cosmic time. We report ALMA detections of the rest-frame ˜300 μm continuum observed at 240 GHz for 45 massive (< {log}({M}\\star ({M}⊙ ))> =10.7), normal star-forming (< {log}({sSFR}({{yr}}-1))> =-8.6), i.e., MS, galaxies at z≈ 3.2 in the COSMOS field. From an empirical calibration between cold neutral, i.e., molecular and atomic, gas mass {M}{gas} and monochromatic (rest-frame) infrared luminosity, the gas mass for this sample is derived. Combined with stellar mass {M}\\star and star formation rate (SFR) estimates (from MagPhys fits) we obtain a median gas fraction of {μ }{gas}={M}{gas}/{M}\\star ={1.65}-0.19+0.18 and a median gas depletion time {t}{depl.}({Gyr})={M}{gas/{SFR}}={0.68}-0.08+0.07; correction for the location on the MS will only slightly change the values. The reported uncertainties are the 1σ error on the median. Our results are fully consistent with the expected flattening of the redshift evolution from the 2-SFM (2 star formation mode) framework which empirically prescribes the evolution assuming a universal, log-linear relation between SFR and gas mass coupled to the redshift evolution of the specific star formation rate (sSFR) of MS galaxies. While {t}{depl.} shows only a mild dependence on location within the MS, a clear trend of increasing {μ }{gas} across the MS is observed (as known from previous studies). Further, we comment on trends within the MS and (in)consistencies with other studies.

  13. Cryogenic Transport of High-Pressure-System Recharge Gas

    NASA Technical Reports Server (NTRS)

    Ungar, Eugene K,; Ruemmele, Warren P.; Bohannon, Carl

    2010-01-01

    A method of relatively safe, compact, efficient recharging of a high-pressure room-temperature gas supply has been proposed. In this method, the gas would be liquefied at the source for transport as a cryogenic fluid at or slightly above atmospheric pressure. Upon reaching the destination, a simple heating/expansion process would be used to (1) convert the transported cryogenic fluid to the room-temperature, high-pressure gaseous form in which it is intended to be utilized and (2) transfer the resulting gas to the storage tank of the system to be recharged. In conventional practice for recharging high-pressure-gas systems, gases are transported at room temperature in high-pressure tanks. For recharging a given system to a specified pressure, a transport tank must contain the recharge gas at a much higher pressure. At the destination, the transport tank is connected to the system storage tank to be recharged, and the pressures in the transport tank and the system storage tank are allowed to equalize. One major disadvantage of the conventional approach is that the high transport pressure poses a hazard. Another disadvantage is the waste of a significant amount of recharge gas. Because the transport tank is disconnected from the system storage tank when it is at the specified system recharge pressure, the transport tank still contains a significant amount of recharge gas (typically on the order of half of the amount transported) that cannot be used. In the proposed method, the cryogenic fluid would be transported in a suitably thermally insulated tank that would be capable of withstanding the recharge pressure of the destination tank. The tank would be equipped with quick-disconnect fluid-transfer fittings and with a low-power electric heater (which would not be used during transport). In preparation for transport, a relief valve would be attached via one of the quick-disconnect fittings (see figure). During transport, the interior of the tank would be kept at a near

  14. Resonance Line Formation in Moving Gas Flows with High Porosity

    NASA Astrophysics Data System (ADS)

    Shulman, S. G.

    2017-06-01

    The formation of resonance lines in gas flows generated by interactions of circumstellar gas with a star's magnetosphere is examined. An effective method is proposed for calculating these lines when the magnetospheric wind is highly porous. The resonance sodium lines observed in the spectrum of UX Ori type star RZ Psc are modelled as an example. It is shown that the narrow absorptions observed in the short wavelength wings of these lines can be formed by scattering of the star's radiation in two gas jets that are semitransparent at the line frequencies when they cross the line of sight.

  15. Optical Diagnostics of Nonequilibrium Phenomena in Highly Rarefied Gas Flows

    NASA Astrophysics Data System (ADS)

    Niimi, Tomohide

    2003-05-01

    The necessity of non-intrusive measurement of the thermodynamic variables in rarefied gas flows has motivated the development of optical diagnostics, such as electron beam fluorescence, laser induced fluorescence, coherent anti-Stokes Raman scattering, and so on. These spectroscopic methods have enabled to detect the nonequilibrium in the gas flows, based on the internal energy distributions obtained from spectral profiles. In this paper, the laser-based techniques for detection of the nonequilibrium phenomena in the highly rarefied gas flows and some results obtained by us are described.

  16. High octane ethers from synthesis gas-derived alcohols

    SciTech Connect

    Klier, K.; Herman, R.G.; Johansson, M.; Feeley, O.C.

    1992-01-01

    The objective of the proposed research is to synthesize high octane ethers, primarily methyl isobutyl ether (MIBE) and methyl tertiary butyl ether (MTBE), directly from H{sub 2}/CO/CO{sub 2} coal-derived synthesis gas via alcohol mixtures that are rich in methanol and 2-methyl-1-propanol (isobutanol). The overall scheme involves gasification of coal, purification and shifting of the synthesis gas, higher alcohol synthesis, and direct synthesis of ethers.

  17. High octane ethers from synthesis gas-derived alcohols

    SciTech Connect

    Klier, K.; Herman, R.G.; Johansson, M.A.; Feeley, O.C.

    1992-04-01

    The objective of the proposal research is to synthesize high octane ethers, primarily methyl isobutyl ether (MIBE) and methyl tertiary butyl ether (MTBE), directly from H{sub 2}/CO/CO{sub 2} coal-derived synthesis gas via alcohol mixtures that are rich in methanol and 2-methyl-1-propanol (isobutanol). The overall scheme involves gasification of coal, purification and shifting of the synthesis gas, higher alcohol synthesis, and direct synthesis of ethers.

  18. Polymorphic Transformation in Mixtures of High- and Low-Melting Fractions of Milk Fat

    SciTech Connect

    Cisneros,A.; Mazzanti, G.; Campos, R.; Marangoni, A.

    2006-01-01

    The kinetics of crystallization of high-melting fraction (HMF) and a mixture of 40% HMF and 60% low-melting fraction (LMF) of milk fat were studied at 5 C by time-resolved in-situ synchrotron X-ray diffraction. HMF crystallized in the {alpha} polymorph, had a longer lifetime than the ones previously reported in pure milk fat, and was almost completely solid. The HMF/LMF mixture crystallized initially in the {alpha} form and transformed into the {beta}' polymorph, with a solid fat content much lower than that of HMF. The polymorphic change was therefore attributed to a delayed sudden formation of {beta}' mixed crystals from the uncrystallized melt. These findings are important for the food industry and as fundamental knowledge to improve our understanding of the origin of the macroscopic physical properties of solid milk fat fractions used in many manufacturing processes.

  19. Fractional model for pharmacokinetics of high dose methotrexate in children with acute lymphoblastic leukaemia

    NASA Astrophysics Data System (ADS)

    Popović, Jovan K.; Spasić, Dragan T.; Tošić, Jela; Kolarović, Jovanka L.; Malti, Rachid; Mitić, Igor M.; Pilipović, Stevan; Atanacković, Teodor M.

    2015-05-01

    The aim of this study is to promote a model based on the fractional differential calculus related to the pharmacokinetic individualization of high dose methotrexate treatment in children with acute lymphoblastic leukaemia, especially in high risk patients. We applied two-compartment fractional model on 8 selected cases with the largest number (4-19) of measured concentrations, among 43 pediatric patients received 24-h methotrexate 2-5 g/m2 infusions. The plasma concentrations were determined by fluorescence polarization immunoassay. Our mathematical procedure, designed by combining Post's and Newton's method, was coded in Mathematica 8.0 and performed on Fujicu Celsius M470-2 PC. Experimental data show that most of the measured values of methotrexate were in decreasing order. However, in certain treatments local maximums were detected. On the other hand, integer order compartmental models do not give values which fit well with the observed data. By the use of our model, we obtained better results, since it gives more accurate behavior of the transmission, as well as the local maximums which were recognized in methotrexate monitoring. It follows from our method that an additional test with a small methotrexate dose can be suggested for the fractional system parameter identification and the prediction of a possible pattern with a full dose in the case of high risk patients. A special feature of the fractional model is that it can also recognize and better fit an observed non-monotonic behavior. A new parameter determination procedure can be successfully used.

  20. Searching for deviations from the general relativity theory with gas mass fraction of galaxy clusters and complementary probes

    NASA Astrophysics Data System (ADS)

    Holanda, R. F. L.; Pereira, S. H.; Santos da Costa, S.

    2017-04-01

    Nowadays, thanks to the improved precision of cosmological data, it has become possible to search for deviation from the general relativity theory with tests on large cosmic scales. Particularly, there is a class of modified gravity theories that breaks the Einstein equivalence principle (EEP) in the electromagnetic sector, generating variations of the fine structure constant, violations of the cosmic distance duality relation, and the evolution law of cosmic microwave background (CMB) radiation. In recent papers, this class of theories has been tested with angular diameter distances from galaxy clusters, type Ia supernovae, and CMB temperature. In this work we propose a new test by considering the most recent x-ray surface brightness observations of galaxy clusters jointly with type Ia supernovae and CMB temperature. The crucial point here is that we take into account the dependence of the x-ray gas mass fraction of galaxy clusters on possible variations of the fine structure constant and violations of the cosmic distance duality relation. Our basic result is that this new approach is competitive with the previous one, and it also does not show significant deviations from general relativity.

  1. Flow pattern, pressure drop and void fraction of two-phase gas-liquid flow in an inclined narrow annular channel

    SciTech Connect

    Wongwises, Somchai; Pipathattakul, Manop

    2006-03-01

    Two-phase flow pattern, pressure drop and void fraction in horizontal and inclined upward air-water two-phase flow in a mini-gap annular channel are experimentally studied. A concentric annular test section at the length of 880mm with an outer diameter of 12.5mm and inner diameter of 8mm is used in the experiments. The flow phenomena, which are plug flow, slug flow, annular flow, annular/slug flow, bubbly/plug flow, bubbly/slug-plug flow, churn flow, dispersed bubbly flow and slug/bubbly flow, are observed and recorded by high-speed camera. A slug flow pattern is found only in the horizontal channel while slug/bubbly flow patterns are observed only in inclined channels. When the inclination angle is increased, the onset of transition from the plug flow region to the slug flow region (for the horizontal channel) and from the plug flow region to slug/bubbly flow region (for inclined channels) shift to a lower value of superficial air velocity. Small shifts are found for the transition line between the dispersed bubbly flow and the bubbly/plug flow, the bubbly/plug flow and the bubbly/slug-plug flow, and the bubbly/plug flow and the plug flow. The rest of the transition lines shift to a higher value of superficial air velocity. Considering the effect of flow pattern on the pressure drop in the horizontal tube at low liquid velocity, the occurrence of slug flow stops the rise of pressure drop for a short while, before rising again after the air velocity has increased. However, the pressure does not rise abruptly in the tubes with {theta}=30{sup o} and 60{sup o} when the slug/bubbly flow occurs. At low gas and liquid velocity, the pressure drop increases, when the inclination angles changes from horizontal to 30{sup o} and 60{sup o}. Void fraction increases with increasing gas velocity and decreases with increasing liquid velocity. After increasing the inclination angle from horizontal to {theta}=30{sup o} and 60{sup o}, the void fraction appears to be similar, with a

  2. Stars and gas in high redshift galaxies

    NASA Astrophysics Data System (ADS)

    Pettini, Max

    Recent advances in instrumentation and observing techniques have made it possible to begin to study in detail the stellar populations and the interstellar media of galaxies at redshift z=3, when the universe was still in its "teen years". In keeping with the theme of this conference, I show how our knowledge of local star-forming regions can be applied directly to these distant galaxies to deduce their ages, metallicities, initial mass function, and masses. I also discuss areas where current limitations in stellar astrophysics have a direct bearing on the interpretation of the data being gathered, at an ever increasing rate, on the high redshift universe.

  3. High-current channel characteristics in high-pressure gas

    NASA Astrophysics Data System (ADS)

    Pinchuk, M. E.; Bogomaz, A. A.; Budin, A. V.; Leont'ev, V. V.; Leks, A. G.; Pozubenkov, A. A.; Rutberg, Ph G.

    2015-11-01

    Research results for discharge initiated by wire explosion in hydrogen at initial pressures up to 30 MPa and current amplitudes up to 1 MA are presented. Measurements of channel radius oscillation amplitude by magnetic probe diagnostics were made to calculate channel plasma parameters. The amplitude of channel radius oscillations was observed to decrease with growth of initial gas pressure and to increase with growth of current amplitude.

  4. Estimate of the Total Mechanical Feedback Energy from Galaxy Cluster-centered Black Holes: Implications for Black Hole Evolution, Cluster Gas Fraction, and Entropy

    NASA Astrophysics Data System (ADS)

    Mathews, William G.; Guo, Fulai

    2011-09-01

    The total feedback energy injected into hot gas in galaxy clusters by central black holes can be estimated by comparing the potential energy of observed cluster gas profiles with the potential energy of non-radiating, feedback-free hot gas atmospheres resulting from gravitational collapse in clusters of the same total mass. Feedback energy from cluster-centered black holes expands the cluster gas, lowering the gas-to-dark-matter mass ratio below the cosmic value. Feedback energy is unnecessarily delivered by radio-emitting jets to distant gas far beyond the cooling radius where the cooling time equals the cluster lifetime. For clusters of mass (4-11) × 1014 M sun, estimates of the total feedback energy, (1-3) × 1063 erg, far exceed feedback energies estimated from observations of X-ray cavities and shocks in the cluster gas, energies gained from supernovae, and energies lost from cluster gas by radiation. The time-averaged mean feedback luminosity is comparable to those of powerful quasars, implying that some significant fraction of this energy may arise from the spin of the black hole. The universal entropy profile in feedback-free gaseous atmospheres in Navarro-Frenk-White cluster halos can be recovered by multiplying the observed gas entropy profile of any relaxed cluster by a factor involving the gas fraction profile. While the feedback energy and associated mass outflow in the clusters we consider far exceed that necessary to stop cooling inflow, the time-averaged mass outflow at the cooling radius almost exactly balances the mass that cools within this radius, an essential condition to shut down cluster cooling flows.

  5. ESTIMATE OF THE TOTAL MECHANICAL FEEDBACK ENERGY FROM GALAXY CLUSTER-CENTERED BLACK HOLES: IMPLICATIONS FOR BLACK HOLE EVOLUTION, CLUSTER GAS FRACTION, AND ENTROPY

    SciTech Connect

    Mathews, William G.; Guo Fulai

    2011-09-10

    The total feedback energy injected into hot gas in galaxy clusters by central black holes can be estimated by comparing the potential energy of observed cluster gas profiles with the potential energy of non-radiating, feedback-free hot gas atmospheres resulting from gravitational collapse in clusters of the same total mass. Feedback energy from cluster-centered black holes expands the cluster gas, lowering the gas-to-dark-matter mass ratio below the cosmic value. Feedback energy is unnecessarily delivered by radio-emitting jets to distant gas far beyond the cooling radius where the cooling time equals the cluster lifetime. For clusters of mass (4-11) x 10{sup 14} M{sub sun}, estimates of the total feedback energy, (1-3) x 10{sup 63} erg, far exceed feedback energies estimated from observations of X-ray cavities and shocks in the cluster gas, energies gained from supernovae, and energies lost from cluster gas by radiation. The time-averaged mean feedback luminosity is comparable to those of powerful quasars, implying that some significant fraction of this energy may arise from the spin of the black hole. The universal entropy profile in feedback-free gaseous atmospheres in Navarro-Frenk-White cluster halos can be recovered by multiplying the observed gas entropy profile of any relaxed cluster by a factor involving the gas fraction profile. While the feedback energy and associated mass outflow in the clusters we consider far exceed that necessary to stop cooling inflow, the time-averaged mass outflow at the cooling radius almost exactly balances the mass that cools within this radius, an essential condition to shut down cluster cooling flows.

  6. Highly crosslinked silicon polymers for gas chromatography columns

    NASA Technical Reports Server (NTRS)

    Shen, Thomas C. (Inventor)

    1994-01-01

    A new highly crosslinked silicone polymer particle for gas chromatography application and a process for synthesizing such copolymer are described. The new copolymer comprises vinyltriethoxysilane and octadecyltrichlorosilane. The copolymer has a high degree of crosslinking and a cool balance of polar to nonpolar sites in the porous silicon polymer assuring fast separation of compounds of variable polarity.

  7. Preparation of high temperature gas-cooled reactor fuel element

    DOEpatents

    Bradley, Ronnie A.; Sease, John D.

    1976-01-01

    This invention relates to a method for the preparation of high temperature gas-cooled reactor (HTGR) fuel elements wherein uncarbonized fuel rods are inserted in appropriate channels of an HTGR fuel element block and the entire block is inserted in an autoclave for in situ carbonization under high pressure. The method is particularly applicable to remote handling techniques.

  8. Thermophoresis of a Small Evaporating Particle in a High-Temperature Diatomic Gas

    PubMed

    Chen

    1997-07-15

    Kinetic-theory analytical results are presented concerning the effect of intense evaporation on the thermophoretic force acting on a spherical particle suspended in a high-temperature diatomic gas for the case of free-molecule regime. Molecule dissociation and atom recombination are included in the analysis. It has been shown that evaporation may substantially enhance the thermophoretic force acting on a particle, especially for the case of the particle materials with low evaporation latent heat and small molecular weight and at high gas temperatures. The values of the effective atomic and molecular thermal-accommodation factors do not affect the thermophoretic force acting on a nonevaporating particle, but they affect significantly the evaporation-added thermophoretic force. It has been shown that the recombination fraction of atoms at the particle surface does not influence the thermophoresis.

  9. High Speed Size Sorting of Subcellular Organelles by Flow Field-Flow Fractionation.

    PubMed

    Yang, Joon Seon; Lee, Ju Yong; Moon, Myeong Hee

    2015-06-16

    Separation/isolation of subcellular species, such as mitochondria, lysosomes, peroxisomes, Golgi apparatus, and others, from cells is important for gaining an understanding of the cellular functions performed by specific organelles. This study introduces a high speed, semipreparative scale, biocompatible size sorting method for the isolation of subcellular organelle species from homogenate mixtures of HEK 293T cells using flow field-flow fractionation (FlFFF). Separation of organelles was achieved using asymmetrical FlFFF (AF4) channel system at the steric/hyperlayer mode in which nuclei, lysosomes, mitochondria, and peroxisomes were separated in a decreasing order of hydrodynamic diameter without complicated preprocessing steps. Fractions in which organelles were not clearly separated were reinjected to AF4 for a finer separation using the normal mode, in which smaller sized species can be well fractionated by an increasing order of diameter. The subcellular species contained in collected AF4 fractions were examined with scanning electron microscopy to evaluate their size and morphology, Western blot analysis using organelle specific markers was used for organelle confirmation, and proteomic analysis was performed with nanoflow liquid chromatography-tandem mass spectrometry (nLC-ESI-MS/MS). Since FlFFF operates with biocompatible buffer solutions, it offers great flexibility in handling subcellular components without relying on a high concentration sucrose solution for centrifugation or affinity- or fluorescence tag-based sorting methods. Consequently, the current study provides an alternative, competitive method for the isolation/purification of subcellular organelle species in their intact states.

  10. Development of Criteria and Identification of Particle Cluster Size Based on Measurements of Void Fraction in Gas-Solid Systems

    SciTech Connect

    David Roelant; Seckin Gokaltun

    2009-06-30

    A circulating fluidized bed (CFB) built at FIU was used to study particle motion in the riser in order to simulate flow regimes in a cold gasifier. High speed imaging was used in order to capture the dynamics of the particles flowing in the riser. The imaging method used here is called the shadow sizing technique which allowed the determination of particle areas and trajectories at various flow rates in the riser. The solid volume fraction and particle velocities calculated using the images acquired during the experiments can be related to granular temperature in order to detect formations of clusters in the riser section of the CFB. The shadow sizing technique was observed to be an effective method in detecting dynamics of particles in motion and formation of clusters when supported with high-speed imaging.

  11. Granular bed filtration of high temperature biomass gasification gas.

    PubMed

    Stanghelle, Daniel; Slungaard, Torbjørn; Sønju, Otto K

    2007-06-18

    High temperature cleaning of producer gas from biomass gasification has been investigated with a granular filter. Field tests were performed for several hours on a single filter element at about 550 degrees C. The results show cake filtration on the granular material and indicate good filtration of the biomass gasification producer gas. The relatively low pressure drop over the filter during filtration is comparable to those of bag filters. The granular filter can operate with high filtration velocities compared to bag filters and maintain high efficiency and a low residual pressure. This work is a part of the BioSOFC-up project that has a goal of utilizing the producer gas from the gasification plant in a solid oxide fuel cell (SOFC). The BioSOFC-up project will continue to the end of 2007.

  12. Highly fractionated Late Eocene (~ 35 Ma) leucogranite in the Xiaru Dome, Tethyan Himalaya, South Tibet

    NASA Astrophysics Data System (ADS)

    Liu, Zhi-Chao; Wu, Fu-Yuan; Ding, Lin; Liu, Xiao-Chi; Wang, Jian-Gang; Ji, Wei-Qiang

    2016-01-01

    The Xiaru dome is located in the middle section of the North Himalayan Gneiss Domes belt in southern Tibet. The leucogranite, which crops out in the core of the Xiaru dome, is a typical medium-grained garnet + tourmaline + muscovite leucogranite. U-(Th)-Pb dating of zircon and monazite from the leucogranite yielded ages of approximately 35 Ma. This finding supports a growing body of evidence indicating that an extensive magmatic event occurred during the late Eocene in the Himalayas. This leucogranite is strongly peraluminous with A/CNK values of 1.08-1.52 and characterized by evolved geochemical composition with high contents of SiO2 and alkali elements; low levels of CaO, MgO, TiO2, and FeOT; enriched large-ion lithophile elements (such as Rb); and depleted of high-field-strength elements (such as Nb, Zr, and Hf). The non-CHARAC (CHarge-And-Radius-Controlled) trace element behaviors, which are typical of a highly fractionated granite system, were recorded in the whole rock and the accessory minerals of the Xiaru leucogranite. Furthermore, the magmatic zircon overgrowths have extremely high content of Hf, consistent with those from the highly fractionated aqueous-like fluid system. In addition, whole-rock geochemical fractionation trends were observed, which can be explained by crystal fractionation of biotite, K-feldspar, zircon, xenotime, and monazite. These geochemical features indicate that the Xiaru leucogranite is a typical highly fractionated granite. The geochronological and geochemical features of the inherited zircons from the Xiaru leucogranite show a close affinity to those of the country rocks, suggesting a certain degree of assimilation from the country rocks during melt ascent and emplacement. Although a restricted range of εHf(t) values from - 12.8 to - 6.6 with Hf TDM2 model ages of 1.2-1.6 Ga was obtained from the late Eocene zircons, it is invalid to constrain the source of the parental magma due to the strong fractionation and assimilation

  13. High CO2 emissions through porous media: Transport mechanisms and implications for flux measurement and fractionation

    USGS Publications Warehouse

    Evans, William C.; Sorey, M.L.; Kennedy, B.M.; Stonestrom, D.A.; Rogie, J.D.; Shuster, D.L.

    2001-01-01

    Diffuse emissions of CO2 are known to be large around some volcanoes and hydrothermal areas. Accumulation-chamber measurements of CO2 flux are increasingly used to estimate the total magmatic or metamorphic CO2 released from such areas. To assess the performance of accumulation chamber systems at fluxes one to three orders of magnitude higher than normally encountered in soil respiration studies, a test system was constructed in the laboratory where known fluxes could be maintained through dry sand. Steady-state gas concentration profiles and fractionation effects observed in the 30-cm sand column nearly match those predicted by the Stefan-Maxwell equations, indicating that the test system was functioning successfully as a uniform porous medium. Eight groups of investigators tested their accumulation chamber equipment, all configured with continuous infrared gas analyzers (IRGA), in this system. Over a flux range of ~ 200-12,000 g m-2 day-1, 90% of their 203 flux measurements were 0-25% lower than the imposed flux with a mean difference of - 12.5%. Although this difference would seem to be within the range of acceptability for many geologic investigations, some potential sources for larger errors were discovered. A steady-state pressure gradient of -20 Pa/m was measured in the sand column at a flux of 11,200 g m-2 day-1. The derived permeability (50 darcies) was used in the dusty-gas model (DGM) of transport to quantify various diffusive and viscous flux components. These calculations were used to demonstrate that accumulation chambers, in addition to reducing the underlying diffusive gradient, severely disrupt the steady-state pressure gradient. The resultant diversion of the net gas flow is probably responsible for the systematically low flux measurements. It was also shown that the fractionating effects of a viscous CO2 efflux against a diffusive influx of air will have a major impact on some important geochemical indicators, such as N2/Ar, ??15N-N2, and 4He/22

  14. Fuel performance models for high-temperature gas-cooled reactor core design

    SciTech Connect

    Stansfield, O.M.; Simon, W.A.; Baxter, A.M.

    1983-09-01

    Mechanistic fuel performance models are used in high-temperature gas-cooled reactor core design and licensing to predict failure and fission product release. Fuel particles manufactured with defective or missing SiC, IPyC, or fuel dispersion in the buffer fail at a level of less than 5 x 10/sup -4/ fraction. These failed particles primarily release metallic fission products because the OPyC remains intact on 90% of the particles and retains gaseous isotopes. The predicted failure of particles using performance models appears to be conservative relative to operating reactor experience.

  15. Toxicity identification fractionation of environmental estrogens in waste water and sludge using gas and liquid chromatography coupled to mass spectrometry and recombinant yeast assay.

    PubMed

    Fernandez, Marc P; Noguerol, Tania-Noelia; Lacorte, Silvia; Buchanan, Ian; Piña, Benjamin

    2009-02-01

    We developed a toxicity identification fractionation (TIF) procedure to determine estrogenic compounds in wastewaters and sludge. The procedure consisted in fractionation of samples through a C(18) solid-phase extraction cartridge, in which Fraction I contained nonylphenol (NP) and its mono (NPEO(1)) and diethoxylate (NPEO(2)) and the markers of faecal exposure, Fraction II contained bisphenol A (BPA) and synthetic and natural hormones, and Fraction III contained the hormone conjugates. These three fractions were analyzed in parallel using gas or liquid chromatography coupled to mass spectrometry and recombinant yeast assay (RYA). Water samples collected daily throughout a whole week contained from 0.45 to 7.22 microg L(-1) of NP > NPEO(1) > NPEO(2) and were responsible for the estrogenicity of these samples. Fractions II and III were not estrogenic and that was due to the low ng L(-1) level of hormones and hormone conjugates found, respectively. The biological treatment sewage treatment plant (STP) was capable to eliminate from 52 to 100% of the compounds, with bisphenol A being the least removed. Only alkylphenols were accumulated in sludge with concentrations from 8.69 to 26.3 mg kg(-1) dw of NPEO(1) > NPEO(2) > NP. The integrated procedure herein proposed can be used as a screening method to evaluate estrogenic compounds in STPs and to survey faecal elimination.

  16. Qualitative Characterization of the Aqueous Fraction from Hydrothermal Liquefaction of Algae Using 2D Gas Chromatography with Time-of-flight Mass Spectrometry.

    PubMed

    Maddi, Balakrishna; Panisko, Ellen; Albrecht, Karl; Howe, Daniel

    2016-03-06

    Two-dimensional gas chromatography coupled with time-of-flight mass spectrometry is a powerful tool for identifying and quantifying chemical components in complex mixtures. It is often used to analyze gasoline, jet fuel, diesel, bio-diesel and the organic fraction of bio-crude/bio-oil. In most of those analyses, the first dimension of separation is non-polar, followed by a polar separation. The aqueous fractions of bio-crude and other aqueous samples from biofuels production have been examined with similar column combinations. However, sample preparation techniques such as derivatization, solvent extraction, and solid-phase extraction were necessary prior to analysis. In this study, aqueous fractions obtained from the hydrothermal liquefaction of algae were characterized by two-dimensional gas chromatography coupled with time-of-flight mass spectrometry without prior sample preparation techniques using a polar separation in the first dimension followed by a non-polar separation in the second. Two-dimensional plots from this analysis were compared with those obtained from the more traditional column configuration. Results from qualitative characterization of the aqueous fractions of algal bio-crude are discussed in detail. The advantages of using a polar separation followed by a non-polar separation for characterization of organics in aqueous samples by two-dimensional gas chromatography coupled with time-of-flight mass spectrometry are highlighted.

  17. Qualitative Characterization of the Aqueous Fraction from Hydrothermal Liquefaction of Algae Using 2D Gas Chromatography with Time-of-flight Mass Spectrometry

    SciTech Connect

    Maddi, Balakrishna; Panisko, Ellen; Albrecht, Karl; Howe, Daniel

    2016-01-01

    Two-dimensional gas chromatography coupled with time of flight mass spectrometry is a powerful tool for identifying and quantifying components in complex mixtures. It has been used to analyze gasoline, jet fuel, diesel, bio-diesel and organic fraction of bio-crude/bio-oil. In these experiments, the first dimension of separation was non-polar, followed by a polar separation. Aqueous fractions of bio-crude and other aqueous samples have been examined with similar column combinations. However, sample preparation techniques such as derivatization, solvent extraction, and solid-phase extraction were necessary prior to analysis. In this study, aqueous fraction obtained from hydrothermal liquefaction of algae was characterized by two-dimensional gas chromatography coupled with time of flight mass spectrometry without prior sample preparation techniques using a polar separation in the first dimension followed by a non-polar separation. Two-dimensional plots from this analysis were compared with those obtained from the more traditional column combination. Results from qualitative characterization aqueous fractions of algal bio-crude are discussed in detail. The advantages of using a polar separation followed by a non-polar separation for characterization of organics in aqueous samples by two-dimensional gas chromatography coupled with time of flight mass spectrometry are highlighted.

  18. Gas permeation through a high density polyethylene microwave window

    SciTech Connect

    Viet Nguyen-Tuong

    1993-07-01

    Due to its low dielectric constant and low loss tangent, high density polyethylene (HDPE) has been selected for use as a high power microwave vacuum window in the Continuous Electron Beam Accelerator Facility cryounit. This window isolates the cryounit waveguide vacuum from the dry air in the external waveguide system. Gas permeation through the window will lead to cryopumping of the gas onto the cold waveguide walls and the cold ceramic window of the superconducting cavity. The gas load from permeation and outgassing of the window have to be minimized, due to the possibility of arcing when high power is applied through the waveguide. The outgassing and permeation of air through the 3.2 mm thick HDPE window were measured using the throughput method. A typical outgassing rate of 5.0 x 10{sup -1} Torr l/s/cm{sup 2} for samples baked out at 70 C was observed 20 h after pump down and bakeout. The gas load due to permeation through 34 cm{sup 2} of the window was 1.6 x 10 {sup -7} Torr l/s. The gas permeation through the 3.2 mm thick HDPE coated with a 300 nm barrier layer of SiO{sub x} was also investigated. No improvement was observed. It was presumably due to the presence of defects in the deposited SiO{sub x} layer.

  19. X-ray constraints on the fraction of obscured active galactic nuclei at high accretion luminosities

    NASA Astrophysics Data System (ADS)

    Georgakakis, A.; Salvato, M.; Liu, Z.; Buchner, J.; Brandt, W. N.; Ananna, T. Tasnim; Schulze, A.; Shen, Yue; LaMassa, S.; Nandra, K.; Merloni, A.; McGreer, I. D.

    2017-08-01

    The wide-area XMM-XXL X-ray survey is used to explore the fraction of obscured active galactic nuclei (AGNs) at high accretion luminosities, LX(2-10 keV) ≳ 1044 erg s - 1, and out to redshift z ≈ 1.5. The sample covers an area of about 14 deg2 and provides constraints on the space density of powerful AGNs over a wide range of neutral hydrogen column densities extending beyond the Compton-thick limit, NH ≈ 1024 cm - 2. The fraction of obscured Compton-thin (NH = 1022-1024 cm - 2) AGNs is estimated to be ≈0.35 for luminosities LX(2-10 keV) > 1044 erg s - 1, independent of redshift. For less luminous sources, the fraction of obscured Compton-thin AGNs increases from 0.45 ± 0.10 at z = 0.25 to 0.75 ± 0.05 at z = 1.25. Studies that select AGNs in the infrared via template fits to the observed spectral energy distribution of extragalactic sources estimate space densities at high accretion luminosities consistent with the XMM-XXL constraints. There is no evidence for a large population of AGNs (e.g. heavily obscured) identified in the infrared and missed at X-ray wavelengths. We further explore the mid-infrared colours of XMM-XXL AGNs as a function of accretion luminosity, column density and redshift. The fraction of XMM-XXL sources that lie within the mid-infrared colour wedges defined in the literature to select AGNs is primarily a function of redshift. This fraction increases from about 20-30 per cent at z = 0.25 to about 50-70 per cent at z = 1.5.

  20. High methane natural gas/air explosion characteristics in confined vessel.

    PubMed

    Tang, Chenglong; Zhang, Shuang; Si, Zhanbo; Huang, Zuohua; Zhang, Kongming; Jin, Zebing

    2014-08-15

    The explosion characteristics of high methane fraction natural gas were investigated in a constant volume combustion vessel at different initial conditions. Results show that with the increase of initial pressure, the peak explosion pressure, the maximum rate of pressure rise increase due to a higher amount (mass) of flammable mixture, which delivers an increased amount of heat. The increased total flame duration and flame development time result as a consequence of the higher amount of flammable mixture. With the increase of the initial temperature, the peak explosion pressures decrease, but the pressure increase during combustion is accelerated, which indicates a faster flame speed and heat release rate. The maximum value of the explosion pressure, the maximum rate of pressure rise, the minimum total combustion duration and the minimum flame development time is observed when the equivalence ratio of the mixture is 1.1. Additionally, for higher methane fraction natural gas, the explosion pressure and the maximum rate of pressure rise are slightly decreased, while the combustion duration is postponed. The combustion phasing is empirically correlated with the experimental parameters with good fitting performance. Furthermore, the addition of dilute gas significantly reduces the explosion pressure, the maximum rate of pressure rise and postpones the flame development and this flame retarding effect of carbon dioxide is stronger than that of nitrogen. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. A new procedure for the determination of distillation temperature distribution of high-boiling petroleum products and fractions.

    PubMed

    Boczkaj, Grzegorz; Przyjazny, Andrzej; Kamiński, Marian

    2011-03-01

    The distribution of distillation temperatures of liquid and semi-fluid products, including petroleum fractions and products, is an important process and practical parameter. It provides information on properties of crude oil and content of particular fractions, classified on the basis of their boiling points, as well as the optimum conditions of atmospheric or vacuum distillation. At present, the distribution of distillation temperatures is often investigated by simulated distillation (SIMDIS) using capillary gas chromatography (CGC) with a short capillary column with polydimethylsiloxane as the stationary phase. This paper presents the results of investigations on the possibility of replacing currently used CGC columns for SIMDIS with a deactivated fused silica capillary tube without any stationary phase. The SIMDIS technique making use of such an empty fused silica column allows a considerable lowering of elution temperature of the analytes, which results in a decrease of the final oven temperature while ensuring a complete separation of the mixture. This eliminates the possibility of decomposition of less thermally stable mixture components and bleeding of the stationary phase which would result in an increase of the detector signal. It also improves the stability of the baseline, which is especially important in the determination of the end point of elution, which is the basis for finding the final temperature of distillation. This is the key parameter for the safety process of hydrocracking, where an excessively high final temperature of distillation of a batch can result in serious damage to an expensive catalyst bed. This paper compares the distribution of distillation temperatures of the fraction from vacuum distillation of petroleum obtained using SIMDIS with that obtained by the proposed procedure. A good agreement between the two procedures was observed. In addition, typical values of elution temperatures of n-paraffin standards obtained by the two

  2. Aspect Ratio Scaling of Ideal No-wall Stability Limits in High Bootstrap Fraction Tokamak Plasmas

    SciTech Connect

    J.E. Menard; M.G. Bell; R.E. Bell; D.A. Gates; S.M. Kaye; B.P. LeBlanc; R. Maingi; S.A. Sabbagh; V. Soukhanovskii; D. Stutman; the NSTX National Research Team

    2003-11-25

    Recent experiments in the low aspect ratio National Spherical Torus Experiment (NSTX) [M. Ono et al., Nucl. Fusion 40 (2000) 557] have achieved normalized beta values twice the conventional tokamak limit at low internal inductance and with significant bootstrap current. These experimental results have motivated a computational re-examination of the plasma aspect ratio dependence of ideal no-wall magnetohydrodynamic stability limits. These calculations find that the profile-optimized no-wall stability limit in high bootstrap fraction regimes is well described by a nearly aspect ratio invariant normalized beta parameter utilizing the total magnetic field energy density inside the plasma. However, the scaling of normalized beta with internal inductance is found to be strongly aspect ratio dependent at sufficiently low aspect ratio. These calculations and detailed stability analyses of experimental equilibria indicate that the nonrotating plasma no-wall stability limit has been exceeded by as much as 30% in NSTX in a high bootstrap fraction regime.

  3. Extreme Ultraviolet Fractional Orbital Angular Momentum Beams from High Harmonic Generation.

    PubMed

    Turpin, Alex; Rego, Laura; Picón, Antonio; San Román, Julio; Hernández-García, Carlos

    2017-03-10

    We investigate theoretically the generation of extreme-ultraviolet (EUV) beams carrying fractional orbital angular momentum. To this end, we drive high-order harmonic generation with infrared conical refraction (CR) beams. We show that the high-order harmonic beams emitted in the EUV/soft x-ray regime preserve the characteristic signatures of the driving beam, namely ringlike transverse intensity profile and CR-like polarization distribution. As a result, through orbital and spin angular momentum conservation, harmonic beams are emitted with fractional orbital angular momentum, and they can be synthesized into structured attosecond helical beams -or "structured attosecond light springs"- with rotating linear polarization along the azimuth. Our proposal overcomes the state of the art limitations for the generation of light beams far from the visible domain carrying non-integer orbital angular momentum and could be applied in fields such as diffraction imaging, EUV lithography, particle trapping, and super-resolution imaging.

  4. Highly efficient organosolv fractionation of cornstalk into cellulose and lignin in organic acids.

    PubMed

    Shui, Tao; Feng, Shanghuan; Yuan, Zhongshun; Kuboki, Takashi; Xu, Chunbao Charles

    2016-10-01

    In this study, effects of fractionation solvents, catalysts, temperatures and residence time on yields, purity and chemical composition of the products were investigated at the solid/solvent ratio of 1:5 (g/g). It was revealed that mixture of acetic acid/formic acid/water at the ratio of 3:6:1 (v/v/v) resulted in crude cellulose and lignin products of relatively high purity. The use of HCl catalyst contributed to a high crude cellulose yield, while H2SO4 showed an adverse effect on cellulose yield. However, both of these acidic catalysts contributed to much lower hemicellulose contents in the resulted crude cellulose products compared with those obtained without a catalyst. Fractionation at 90°C for 180min in mixed solvents of acetic acid/formic acid/water (3:6:1, v/v/v) with or without catalyst produced crude cellulose with very low residual lignin contents (<4%).

  5. Iron isotopic fractionation between silicate mantle and metallic core at high pressure

    NASA Astrophysics Data System (ADS)

    Liu, Jin; Dauphas, Nicolas; Roskosz, Mathieu; Hu, Michael Y.; Yang, Hong; Bi, Wenli; Zhao, Jiyong; Alp, Esen E.; Hu, Justin Y.; Lin, Jung-Fu

    2017-02-01

    The +0.1‰ elevated 56Fe/54Fe ratio of terrestrial basalts relative to chondrites was proposed to be a fingerprint of core-mantle segregation. However, the extent of iron isotopic fractionation between molten metal and silicate under high pressure-temperature conditions is poorly known. Here we show that iron forms chemical bonds of similar strengths in basaltic glasses and iron-rich alloys, even at high pressure. From the measured mean force constants of iron bonds, we calculate an equilibrium iron isotope fractionation between silicate and iron under core formation conditions in Earth of ~0-0.02‰, which is small relative to the +0.1‰ shift of terrestrial basalts. This result is unaffected by small amounts of nickel and candidate core-forming light elements, as the isotopic shifts associated with such alloying are small. This study suggests that the variability in iron isotopic composition in planetary objects cannot be due to core formation.

  6. Extreme Ultraviolet Fractional Orbital Angular Momentum Beams from High Harmonic Generation

    NASA Astrophysics Data System (ADS)

    Turpin, Alex; Rego, Laura; Picón, Antonio; San Román, Julio; Hernández-García, Carlos

    2017-03-01

    We investigate theoretically the generation of extreme-ultraviolet (EUV) beams carrying fractional orbital angular momentum. To this end, we drive high-order harmonic generation with infrared conical refraction (CR) beams. We show that the high-order harmonic beams emitted in the EUV/soft x-ray regime preserve the characteristic signatures of the driving beam, namely ringlike transverse intensity profile and CR-like polarization distribution. As a result, through orbital and spin angular momentum conservation, harmonic beams are emitted with fractional orbital angular momentum, and they can be synthesized into structured attosecond helical beams –or “structured attosecond light springs”– with rotating linear polarization along the azimuth. Our proposal overcomes the state of the art limitations for the generation of light beams far from the visible domain carrying non-integer orbital angular momentum and could be applied in fields such as diffraction imaging, EUV lithography, particle trapping, and super-resolution imaging.

  7. The Physical Conditions of Atomic Gas at High Redshift

    NASA Astrophysics Data System (ADS)

    Neeleman, Marcel

    In this thesis we provide insight into the chemical composition, physical conditions and cosmic distribution of atomic gas at high redshift. We study this gas in absorption against bright background quasars in absorption systems known as Damped Ly-alpha Systems (DLAs). These systems contain the bulk of the atomic gas at high redshift and are the likely progenitors of modern-day galaxies. In Chapter 2, we find that the atomic gas in DLAs obeys a mass-metallicity relationship that is similar to the mass-metallicity relationship seen in star-forming galaxies. The evolution of this relationship is linear with redshift, allowing for a planar equation to accurately describe this evolution, which provides a more stringent constraint on simulations modeling DLAs. Furthermore, the concomitant evolution of the mass-metallicity relationship of atomic gas and star-forming galaxies suggests an intimate link between the two. We next use a novel way to measure the physical conditions of the gas by using fine-structure line ratios of singly ionized carbon and silicon. By measuring the density of the upper and lower level states, we are able to determine the temperature, hydrogen density and electron density of the gas. We find that the conditions present in this high redshift gas are consistent with the conditions we see in the local interstellar medium (ISM). A few absorbers have higher than expected pressure, which suggests that they probe the ISM of star-forming galaxies. Finally in Chapter 4, we measure the cosmic neutral hydrogen density at redshifts below 1.6. Below this redshift, the Ly-alpha line of hydrogen is absorbed by the atmosphere, making detection difficult. Using the archive of the Hubble Space Telescope, we compile a comprehensive list of quasars for a search of DLAs at redshift below 1.6. We find that the incidence rate of DLAs and the cosmic neutral hydrogen density is smaller than previously measured, but consistent with the values both locally and at

  8. Method of processing a high-boiling fraction obtained in the cracking of hydrocarbons

    SciTech Connect

    Horner, B.; Lang, U.; Wernicke, H.J.

    1981-01-13

    A process for the treatment of a hydrocarbon fraction having a boiling point range beginning above 200* C. and obtained in the cracking of hydrocarbons, in which the polymeric component resulting from the cracking pyrolysis is removed and the remaining polymer-free hydrocarbon is subjected to hydrogenation under such reaction conditions that the product is high in monoaromatic components while the polyaromatics are removed therefrom.

  9. Cup-Drawing Behavior of High-Strength Steel Sheets Containing Different Volume Fractions of Martensite

    SciTech Connect

    Choi, Shi-Hoon; Kim, Dae-Wan; Yang, Hoe-Seok; Han, Seong-Ho; Yoon, Jeong Whan

    2010-06-15

    Planar anisotropy and cup-drawing behavior were investigated for high-strength steel sheets containing different volume fractions of martensite. Macrotexture analysis using XRD was conducted to capture the effect of crystallographic orientation on the planar anisotropy of high-strength steel sheets. A phenomenological yield function, Yld96, which accounts for the anisotropy of yield stress and r-values, was implemented into ABAQUS using the user subroutine UMAT. Cup drawing of high-strength steel sheets was simulated using the FEM code. The profiles of earing and thickness strain were compared with the experimentally measured results.

  10. High Pressure Supersonic Gas Jet Fueling on NSTX

    SciTech Connect

    Soukhanovskii, V; Bell, M; Blanchard, W; Dong, J; Gernhardt, R; Kaita, R; Kugel, H; Provost, T; Roquemore, A; Sichta, P

    2007-06-25

    A supersonic gas injector (SGI) has been developed for fueling and diagnostic applications on NSTX. The SGI is comprised of a small de Laval converging-diverging graphite nozzle, a commercial piezoelectric gas valve, and a diagnostic package, all mounted on a movable probe at a low field side midplane port location. The nozzle operated in a pulsed regime at room temperature, reservoir deuterium pressure up to 2500 Torr (50 PSIA), flow rate up to 65 Torr l /s (4.55e21 particles/s), and a measured Mach number of about 4. In initial experiments the SGI was used for fueling of ohmic and 2 - 6 MW NBI-heated L- and H-mode plasmas. Reliable H-mode access was obtained with SGI fueling, with a fueling efficiency in the range 0.1 - 0.3. Good progress was also made toward a controlled density SGI-fueled H-mode plasma scenario with the flow rate of the uncontrolled high field side (HFS) gas injector reduced by up to 20. These experiments motivated a number of SGI upgrades: (1) the maximum plenum pressure has been increased to 5000 Torr (100 PSIA), (2) the plenum pressure volume has been doubled, (3) the gas delivery system has been changed to allow for injection of various gases, (4) a multi-pulse capability has been implemented. As a result of the upgrades, the maximum flow rate increased to about 130 Torr l /s. Laboratory gas jet characterization tests indicated a Mach number of about 4 with H2 and D2, and 4-6 with He and N2. Plasma experiments demonstrated the high-pressure gas jet fueling compatibility with H-mode plasmas, high fueling efficiency (0.1 - 0.3), and high SOL penetration.

  11. A high-dispersion molecular gas component in nearby galaxies

    SciTech Connect

    Caldú-Primo, Anahi; Walter, Fabian; Sandstrom, Karin; Schruba, Andreas; Leroy, Adam; De Blok, W. J. G.; Ianjamasimanana, R.; Mogotsi, K. M.

    2013-12-01

    We present a comprehensive study of the velocity dispersion of the atomic (H I) and molecular (H{sub 2}) gas components in the disks (R ≲ R {sub 25}) of a sample of 12 nearby spiral galaxies with moderate inclinations. Our analysis is based on sensitive high-resolution data from the THINGS (atomic gas) and HERACLES (molecular gas) surveys. To obtain reliable measurements of the velocity dispersion, we stack regions several kiloparsecs in size, after accounting for intrinsic velocity shifts due to galactic rotation and large-scale motions. We stack using various parameters: the galactocentric distance, star formation rate surface density, H I surface density, H{sub 2} surface density, and total gas surface density. We fit single Gaussian components to the stacked spectra and measure median velocity dispersions for H I of 11.9 ± 3.1 km s{sup –1} and for CO of 12.0 ± 3.9 km s{sup –1}. The CO velocity dispersions are thus, surprisingly, very similar to the corresponding ones of H I, with an average ratio of σ{sub HI}/σ{sub CO}= 1.0 ± 0.2 irrespective of the stacking parameter. The measured CO velocity dispersions are significantly higher (factor of ∼2) than the traditional picture of a cold molecular gas disk associated with star formation. The high dispersion implies an additional thick molecular gas disk (possibly as thick as the H I disk). Our finding is in agreement with recent sensitive measurements in individual edge-on and face-on galaxies and points toward the general existence of a thick disk of molecular gas, in addition to the well-known thin disk in nearby spiral galaxies.

  12. Hydrodesulfurization of Qaiyarah 80-205 sup 0 C naphtha fraction of alumina supported Co-Mo-oxides; Part 2: Using stopped flow gas chromatography

    SciTech Connect

    Ali, L.H.; Sulaiman, S.T.; AlTamer, M.Y. )

    1990-04-01

    The authors report the effective desulfurization of Qaiyarah 80-205{sup 0}C, naphtha fraction on alumina supported Co-Mo oxides, assembled in a GC column using H{sub 2} as a carrier gas and the stopped-flow technique. Over 90% of sulfur was removed from this partially cracked naphtha and a similar result (Ca 90%) was obtained when hydrodesulfurizing an acid-base treated naphtha. /sup 1/H nmr studies on the chromatographically separated hydrodesulfurized fractions revealed interesting structural parameters which leads to suggestions related to the occurrence of a reforming reaction and the liberation of fresh H{sub 2} gases which further promotes hydrodesulfurization.

  13. High accuracy Primary Reference gas Mixtures for high-impact greenhouse gases

    NASA Astrophysics Data System (ADS)

    Nieuwenkamp, Gerard; Zalewska, Ewelina; Pearce-Hill, Ruth; Brewer, Paul; Resner, Kate; Mace, Tatiana; Tarhan, Tanil; Zellweger, Christophe; Mohn, Joachim

    2017-04-01

    Climate change, due to increased man-made emissions of greenhouse gases, poses one of the greatest risks to society worldwide. High-impact greenhouse gases (CO2, CH4 and N2O) and indirect drivers for global warming (e.g. CO) are measured by the global monitoring stations for greenhouse gases, operated and organized by the World Meteorological Organization (WMO). Reference gases for the calibration of analyzers have to meet very challenging low level of measurement uncertainty to comply with the Data Quality Objectives (DQOs) set by the WMO. Within the framework of the European Metrology Research Programme (EMRP), a project to improve the metrology for high-impact greenhouse gases was granted (HIGHGAS, June 2014-May 2017). As a result of the HIGHGAS project, primary reference gas mixtures in cylinders for ambient levels of CO2, CH4, N2O and CO in air have been prepared with unprecedented low uncertainties, typically 3-10 times lower than usually previously achieved by the NMIs. To accomplish these low uncertainties in the reference standards, a number of preparation and analysis steps have been studied and improved. The purity analysis of the parent gases had to be performed with lower detection limits than previously achievable. E.g., to achieve an uncertainty of 2•10-9 mol/mol (absolute) on the amount fraction for N2O, the detection limit for the N2O analysis in the parent gases has to be in the sub nmol/mol domain. Results of an OPO-CRDS analyzer set-up in the 5µm wavelength domain, with a 200•10-12 mol/mol detection limit for N2O, will be presented. The adsorption effects of greenhouse gas components at cylinder surfaces are critical, and have been studied for different cylinder passivation techniques. Results of a two-year stability study will be presented. The fit-for-purpose of the reference materials was studied for possible variation on isotopic composition between the reference material and the sample. Measurement results for a suit of CO2 in air

  14. Identification of Highly Fractionated 18O-Rich Silicate Grains in the Queen Alexandra Range 99177 CR3 Chondrite

    NASA Astrophysics Data System (ADS)

    Nguyen, A. N.; Keller, L. P.; Messenger, S.; Rahman, Z.

    2015-07-01

    Silicate grains with ~5% 18O enrichment are found in the QUE 99177 meteorite. TEM analysis of one grain indicates an aggregate of pyroxene grains and olivine. The grains could have formed from a fractionated 16O-poor gas reservoir.

  15. Gas transport in highly permeable, dry porous media

    NASA Astrophysics Data System (ADS)

    Levintal, Elad; Dragila, Maria I.; Kamai, Tamir; Weisbrod, Noam

    2017-04-01

    Gas exchange between soil and atmosphere is far more efficient via advective than diffusive mechanisms. Whereas advection requires media permeability be sufficiently high and an advecting driving mechanism, diffusion transport occurs in all permeabilities. Traditionally, diffusion models generally have focused only on low permeability media (sand particles and smaller, k < 10-5 cm2). Here we establish the validity of these models to quantify diffusive transport in higher permeability media when climatic conditions do not favor advection. A permeability cutoff is quantified, such that above it traditional diffusion models become inaccurate. Results are based on experiments using large columns filled with different homogeneous spherical particles, conducted inside a climate-controlled laboratory especially designed for quantifying soil-gas diffusivity under isothermal and windless conditions. The results indicate that traditional diffusion models are accurate for permeability values below 2.7×10-3 cm2. Above this threshold, gas transport could not be explained by diffusion alone. Our measurements indicate that for permeability values above this threshold gas flux is higher than can be explained by diffusion, even under stable environmental conditions where advection is not expected. The findings of this research can contribute to better understanding of gas transport in high-permeability porous media such as: aggregated soils, snowpacks and mines stockpiles.

  16. Pyrolysis-gas chromatography/mass spectrometry of a coal extract and its fractions separated by planar chromatography: correlation of structural features with molecular mass

    PubMed

    Islas; Suelves; Carter; Herod; Kandiyoti

    2000-01-01

    The structural characterisation of a coal liquefaction extract and its three fractions separated by planar chromatography has been described. Size exclusion chromatography showed the molecular mass distributions to become progressively larger with decreasing mobility on the plate. UV-fluorescence spectroscopy of the fractions indicated parallel increases in the sizes of polynuclear aromatic ring systems. Analysis by probe-mass spectrometry of the 'whole' coal extract showed the expected array of small polynuclear aromatic groups extending to m/z 450. The probe mass spectra of the lightest fraction ('mobile in pyridine and acetonitrile') showed similar features, except for effects due to vacuum drying to remove solvent. In sharp contrast, the two heaviest fractions ('mobile in pyridine and immobile in acetonitrile' and 'immobile in pyridine') showed no significant ions other than those from residual NMP solvent (m/z 98 and 99). Pyrolysis-gas chromatography/mass spectrometry of these two heaviest fractions showed only traces of aromatic compounds or fragments. The aromatic pyrolysis products of these fractions were too large and involatile to pass through the GC column. The major components observed in the pyrolysis-gas chromatography/mass spectrometry of the two heavy fractions were alkanes and alkenes, ranging between C10-C25. Since none of the samples contained free alkanes, alkenes or cycloalkanes before pyrolysis, they were generated during the pyrolysis step. The shifts of UV-fluorescence spectral intensity to shorter wavelengths with decreasing size indicated by size exclusion chromatography (SEC) provide direct evidence of differences in structure with changing molecular mass. This evidence strongly suggests that species identified as being of large molecular mass in this extract sample are not composed of molecular aggregates. It remains difficult to establish whether and when it would be legitimate to invoke molecular aggregates to explain the large

  17. Experiment on wear behavior of high pressure gas seal faces

    NASA Astrophysics Data System (ADS)

    Xu, Jing; Peng, Xudong; Bai, Shaoxian; Meng, Xiangkai; Li, Jiyun

    2014-11-01

    Current researches show that mechanical deformation of seal ring face makes fluid film clearance decrease at high pressure side, thus a divergent clearance is formed and face wear occurs more seriously at the high pressure side than that on the low pressure side. However, there is still lack of published experimental works enough to prove the theoretical results. In this paper, a spiral groove dry gas seal at high pressures is experimentally investigated so as to prove the face wear happened at the high pressure side of seal faces due to the face mechanical deformation, and the wear behavior affected by seal ring structure is also studied. The experimental results show that face wear would occur at the high pressure side of seal faces due to the deformation, thus the leakage and face temperature increase, which all satisfies the theoretical predictions. When sealed pressure is not less than 5 MPa, the pressure can provide enough opening force to separate the seal faces. The seal ring sizes have obvious influence on face wear. Face wear, leakage and face temperature of a dry gas seal with the smaller cross sectional area of seal ring are less than that of a dry gas seal with bigger one, and the difference of leakage rate between these two sizes of seal face width is in the range of 24%-25%. Compared with the effect of seal ring sizes, the effect of secondary O-ring seal position on face deformation and face wear is less. The differences between these two types of dry gas seals with different secondary O-ring seal positions are less than 5.9% when the rotational speed varies from 0 to 600 r/min. By linking face wear and sealing performance changes to the shift in mechanical deformation of seal ring, this research presents an important experimental method to study face deformation of a dry gas seal at high pressures.

  18. Planned Two-Fraction Proton Beam Stereotactic Radiosurgery for High-Risk Inoperable Cerebral Arteriovenous Malformations

    SciTech Connect

    Hattangadi, Jona A.; Chapman, Paul H.; Bussiere, Marc R.; Niemierko, Andrzej; Ogilvy, Christopher S.; Rowell, Alison; Daartz, Juliane; Loeffler, Jay S.; Shih, Helen A.

    2012-06-01

    Purpose: To evaluate patients with high-risk cerebral arteriovenous malformations (AVMs), based on eloquent brain location or large size, who underwent planned two-fraction proton stereotactic radiosurgery (PSRS). Methods and Materials: From 1991 to 2009, 59 patients with high-risk cerebral AVMs received two-fraction PSRS. Median nidus volume was 23 cc (range, 1.4-58.1 cc), 70% of cases had nidus volume {>=}14 cc, and 34% were in critical locations (brainstem, basal ganglia). Median AVM score based on age, AVM size, and location was 3.19 (range, 0.9-6.9). Many patients had prior surgery or embolization (40%) or prior PSRS (12%). The most common prescription was 16 Gy radiobiologic equivalent (RBE) in two fractions, prescribed to the 90% isodose. Results: At a median follow-up of 56.1 months, 9 patients (15%) had total and 20 patients (34%) had partial obliteration. Patients with total obliteration received higher total dose than those with partial or no obliteration (mean dose, 17.6 vs. 15.5 Gy (RBE), p = 0.01). Median time to total obliteration was 62 months (range, 23-109 months), and 5-year actuarial rate of partial or total obliteration was 33%. Five-year actuarial rate of hemorrhage was 22% (95% confidence interval, 12.5%-36.8%) and 14% (n = 8) suffered fatal hemorrhage. Lesions with higher AVM scores were more likely to hemorrhage (p = 0.024) and less responsive to radiation (p = 0.026). The most common complication was Grade 1 headache acutely (14%) and long term (12%). One patient developed a Grade 2 generalized seizure disorder, and two had mild neurologic deficits. Conclusions: High-risk AVMs can be safely treated with two-fraction PSRS, although total obliteration rate is low and patients remain at risk for future hemorrhage. Future studies should include higher doses or a multistaged PSRS approach for lesions more resistant to obliteration with radiation.

  19. High voltage gas insulated transmission line with continuous particle trapping

    DOEpatents

    Cookson, Alan H.; Dale, Steinar J.

    1983-01-01

    This invention provides a novel high voltage gas insulated transmission line utilizing insulating supports spaced at intervals with snap-in means for supporting a continuous trapping apparatus and said trapping apparatus having perforations and cutouts to facilitate trapping of contaminating particles and system flexibility.

  20. LOX vaporization in high-pressure, hydrogen-rich gas

    NASA Technical Reports Server (NTRS)

    Litchford, Ron J.; Jeng, San-Mou

    1990-01-01

    LOX droplet vaporization in high-pressure hydrogen-rich gas is analyzed, with special attention to thermodynamic effects which compel the surface to heat to the critical state and to supercritical vaporization processes on heating to criticality. Subcritical vaporization is modeled using a quasi-steady diffusion-controlled gas-phase transport formulation coupled to an effective-conductivity internal-energy-transport model accounting for circulation effects. It is demonstrated how the droplet surface might heat to the critical state, for ambient pressures slightly greater than the critical pressure of oxygen, such that the bulk of propellant within the droplet remains substantially below the critical mixing temperature.

  1. NOVEL GAS SENSORS FOR HIGH-TEMPERATURE FOSSIL FUEL APPLICATIONS

    SciTech Connect

    Palitha Jayaweera

    2004-05-01

    SRI is developing ceramic-based microsensors for detection of exhaust gases such as NO, NO{sub 2}, and CO in advanced combustion and gasification systems. The sensors detect the electrochemical activity of the exhaust gas species on catalytic electrodes and are designed to operate at high temperatures, elevated pressures, and corrosive environments typical of large power generation exhausts. Under this research project we are developing sensors for multiple gas detection in a single package along with data acquisition and control software and hardware. The sensor package can be easily integrated into online monitoring systems for active emission control. This report details the research activities performed from October 2003 to April 2004.

  2. Ceramic membranes for gas separation at high temperatures. Final report

    SciTech Connect

    Wang, C.J.

    1994-03-01

    Superior heat, wear, erosion, and corrosion resistance of ceramic materials have motivated the studies of processing-structure-performance interrelationships of ceramic membranes for high temperature gas separations. A literature review on pore transport mechanisms, physical structure of membranes, and module configuration of industrial membrane processes has been made to obtain a better understanding of membrane performance in gas separations. The research experience in decomposing polymer resins for ablative composites has stimulated a research interest in developing a dynamic model for membrane processes, incorporating a temperature effects on material and fluid properties. Brief summaries of the reviewed literature, permeability experiments, and process modeling are presented in this report.

  3. High speed pulse digitization in driftless gas scintillation proportional counters

    SciTech Connect

    Valero, J.; Smith, A.; Peacock, A.

    1988-06-01

    In a driftless gas scintillation proportional counter the observed light burst profile provides a wealth of information both about the incident photon and the transit of the electron cloud through the scintillation region. The different features of such profiles are difficult to separate with conventional analog electronics. In this work the authors apply the technique of high speed pulse digitization to the problem. They show that by this technique not only can the performance of the instrument be improved (e.g. background rejection) but valuable data can be obtained regarding the design of both the gas cell and the analysis electronics.

  4. High order harmonic generation in dual gas multi-jets

    SciTech Connect

    Tosa, Valer E-mail: calin.hojbota@itim-cj.ro; Hojbota, Calin E-mail: calin.hojbota@itim-cj.ro

    2013-11-13

    High order harmonic generation (HHG) in gas media suffers from a low conversion efficiency that has its origins in the interaction of the atom/molecule with the laser field. Phase matching is the main way to enhance the harmonic flux and several solutions have been designed to achieve it. Here we present numerical results modeling HHG in a system of multi-jets in which two gases alternate: the first gas jet (for example Ne) generates harmonics and the second one which ionizes easier, recover the phase matching condition. We obtain configurations which are experimentally feasible with respect to pressures and dimensions of the jets.

  5. Fractionation and delignification of empty fruit bunches with low reaction severity for high sugar recovery.

    PubMed

    Hong, Jin Young; Kim, Young Soo; Oh, Kyeong Keun

    2013-10-01

    Fractionation and delignification of empty fruit bunches (EFB) was conducted in a series of two steps under low reaction severity with the aim of minimizing the neutralization of hydrolyzates. In EFB underwent acid fractionation, the glucan content was increased to 62.4%, at which point 86.9% of the hemicellulosic sugar and 20.5% of the lignin were extracted from the raw EFB. Xylose-rich hydrolyzate, indicating a high selectivity of 17.7 could be separated. Through the consecutive delignification of acid-fractionated EFB using sodium hydroxide, solid residue with a high glucan content (70.4%) and low hemicellulosic sugar content (3.7%) could be obtained, which indicated that 95.9% of the hemicellulosic sugar and 67.5% of the lignin were extracted based on raw EFB. The final pretreated solid residue was converted to glucose through enzyme hydrolysis, which resulted in an enzymatic digestibility of 76.9% was achieved. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Challenges of Using High-Dose Fractionation Radiotherapy in Combination Therapy.

    PubMed

    Yang, Ying-Chieh; Chiang, Chi-Shiun

    2016-01-01

    Radiotherapy is crucial and substantially contributes to multimodal cancer treatment. The combination of conventional fractionation radiotherapy (CFRT) and systemic therapy has been established as the standard treatment for many cancer types. With advances in linear accelerators and image-guided techniques, high-dose fractionation radiotherapy (HFRT) is increasingly introduced in cancer centers. Clinicians are currently integrating HFRT into multimodality treatment. The shift from CFRT to HFRT reveals different effects on the tumor microenvironment and responses, particularly the immune response. Furthermore, the combination of HFRT and drugs yields different results in different types of tumors or using different treatment schemes. We have reviewed clinical trials and preclinical evidence on the combination of HFRT with drugs, such as chemotherapy, targeted therapy, and immune therapy. Notably, HFRT apparently enhances tumor cell killing and antigen presentation, thus providing opportunities and challenges in treating cancer.

  7. On mixed derivatives type high dimensional multi-term fractional partial differential equations approximate solutions

    NASA Astrophysics Data System (ADS)

    Talib, Imran; Belgacem, Fethi Bin Muhammad; Asif, Naseer Ahmad; Khalil, Hammad

    2017-01-01

    In this research article, we derive and analyze an efficient spectral method based on the operational matrices of three dimensional orthogonal Jacobi polynomials to solve numerically the mixed partial derivatives type multi-terms high dimensions generalized class of fractional order partial differential equations. We transform the considered fractional order problem to an easily solvable algebraic equations with the aid of the operational matrices. Being easily solvable, the associated algebraic system leads to finding the solution of the problem. Some test problems are considered to confirm the accuracy and validity of the proposed numerical method. The convergence of the method is ensured by comparing our Matlab software simulations based obtained results with the exact solutions in the literature, yielding negligible errors. Moreover, comparative results discussed in the literature are extended and improved in this study.

  8. Challenges of Using High-Dose Fractionation Radiotherapy in Combination Therapy

    PubMed Central

    Yang, Ying-Chieh; Chiang, Chi-Shiun

    2016-01-01

    Radiotherapy is crucial and substantially contributes to multimodal cancer treatment. The combination of conventional fractionation radiotherapy (CFRT) and systemic therapy has been established as the standard treatment for many cancer types. With advances in linear accelerators and image-guided techniques, high-dose fractionation radiotherapy (HFRT) is increasingly introduced in cancer centers. Clinicians are currently integrating HFRT into multimodality treatment. The shift from CFRT to HFRT reveals different effects on the tumor microenvironment and responses, particularly the immune response. Furthermore, the combination of HFRT and drugs yields different results in different types of tumors or using different treatment schemes. We have reviewed clinical trials and preclinical evidence on the combination of HFRT with drugs, such as chemotherapy, targeted therapy, and immune therapy. Notably, HFRT apparently enhances tumor cell killing and antigen presentation, thus providing opportunities and challenges in treating cancer. PMID:27446811

  9. Experimental Study of High-Z Gas Buffers in Gas-Filled ICF Engines

    SciTech Connect

    Rhodes, M A; Kane, J; Loosmore, G; DeMuth, J; Latkowski, J

    2010-12-03

    ICF power plants, such as the LIFE scheme at LLNL, may employ a high-Z, target-chamber gas-fill to moderate the first-wall heat-pulse due to x-rays and energetic ions released during target detonation. To reduce the uncertainties of cooling and beam/target propagation through such gas-filled chambers, we present a pulsed plasma source producing 2-5 eV plasma comprised of high-Z gases. We use a 5-kJ, 100-ns theta discharge for high peak plasma-heating-power, an electrode-less discharge for minimizing impurities, and unobstructed axial access for diagnostics and beam (and/or target) propagation studies. We will report on the plasma source requirements, design process, and the system design.

  10. Reproductive effects of the water-accommodated fraction of a natural gas condensate in the Indo-Pacific reef-building coral Pocillopora damicornis.

    PubMed

    Villanueva, R D; Yap, H T; Montaño, M N E

    2011-11-01

    Toxic effects of the water-accommodated fraction (WAF) of a natural gas condensate on the reproduction of the brooding coral Pocillopora damicornis were studied in short-term (24 h) laboratory experiments. Coral fragments were exposed to varying concentrations of condensate WAF during different reproductive phases: gametogenesis, early embryogenesis, and late embryogenesis (when nighttime planulation occurs). During gametogenesis, exposure to condensate WAF did not inhibit subsequent production of larvae. On the other hand, exposure to >25% WAF of gravid corals, at early and late embryogenesis, resulted in abortion and early release of larvae, respectively, with higher percentages of larvae expelled in fragments treated with higher concentrations of condensate WAF at least 3h after onset of exposure. Aborted larvae during early embryogenesis were 'premature', as they are of small size (0.06±0.03 mm³), low metamorphic competency (54%), and white in coloration, with a pale brown oral end (indicating low density of zooxanthellae). Those larvae released at the latter part of embryogenesis are bigger in size (0.22±0.08 mm³), possess 100% metamorphic competency, and are brown in coloration (high density of zooxanthellae). Aside from direct effects on reproduction, fragment mortality index was higher in samples exposed to higher concentrations of condensate WAF (>25%), hence lowering the number of potentially reproducing polyps. Altogether, exposure to >25% natural gas condensate WAF for at least 3h can potentially disrupt the replenishment of coral populations due to negative effects on reproduction and early life processes. Copyright © 2011 Elsevier Inc. All rights reserved.

  11. High resolution 3D gas-jet characterization.

    PubMed

    Landgraf, Björn; Schnell, Michael; Sävert, Alexander; Kaluza, Malte C; Spielmann, Christian

    2011-08-01

    We present a tomographic characterization of gas jets employed for high-intensity laser-plasma interaction experiments where the shape can be non-symmetrically. With a Mach-Zehnder interferometer we measured the phase shift for different directions through the neutral density distribution of the gas jet. From the recorded interferograms it is possible to retrieve 3-dimensional neutral density distributions by tomographic reconstruction based on the filtered back projections. We report on criteria for the smallest number of recorded interferograms as well as a comparison with the widely used phase retrieval based on an Abel inversion. As an example for the performance of our approach, we present the characterization of nozzles with rectangular openings or gas jets with shock waves. With our setup we obtained a spatial resolution of less than 60 μm for an Argon density as low as 2 × 10(17) cm(-3).

  12. Simulation of powder metal fabrication with high pressure gas atomization

    SciTech Connect

    Kuntz, D.W.; Payne, J.L.

    1994-12-31

    A computational/analytical technique has been developed which models the physics of high pressure gas atomization. The technique uses an uncoupled approach, such that the gas flowfield is initially calculated with a commercially-available Navier-Stokes code. The liquid metal droplet breakup, dynamics, and thermodynamics, are then calculated using the pre-computed flowfield by a separate computer program written by the authors. The atomization code models the primary breakup of the liquid metal stream, tracks the droplets resulting from primary breakup through the flowfield until they undergo secondary breakup, and then tracks the subdroplets until they breakup, solidify, or leave the flowfield region of interest. The statistical properties of the metal powder produced are then computed from the characteristics of these droplets. Comparisons between experimental measurements and computations indicate that the Navier-Stokes code is predicting the gas flowfield well, and that the atomization code is properly modeling the physics of the droplet dynamics and breakup.

  13. High-temperature gas stream filter and method

    SciTech Connect

    Notestein, J.E.

    1994-12-31

    The present invention relates generally to the removal of solid particulate material from high-temperature gas streams, and more particularly the removal of such particulate material by employing a barrier filter formed of a carbon-carbon composite provided by a porous carbon fiber substrate with open interstitial regions between adjacently disposed carbon fibers selectively restricted by carbon integrally attached to the carbon fibers of the substrate. In a typical utilization of a particulate-bearing hot gas stream, the particulate loading of the gas stream after cleaning is normally less than about 50 ppm and with essentially no particulates larger than about 10 microns. This carbon-carbon filter for removing particulate material of a particle size larger than a preselected particle size from a gas stream at a temperature greater than about 800 F, is produced by the steps which comprise: providing a substrate of carbonaceous fibers with pore-forming open interstitial regions between adjacently disposed fibers; and, sufficiently filling these open interstitial regions with carbon integrally attached to and supported by the fibers for providing the interstitial regions with throughgoing passage-ways of a pore size sufficient to provide for the passage of the gas stream while preventing the passage of particulate material larger than a preselected particle size.

  14. On high suppression of NO x and CO emissions in gas-turbine plants with combined gas-and-steam cycles

    NASA Astrophysics Data System (ADS)

    Ivanov, A. A.; Ermakov, A. N.; Shlyakhov, R. A.

    2010-12-01

    In this work are given results of analyzing processes of production of nitrogen oxides (NO x ) and afterburning of CO when firing natural gas at combined-cycle gas-turbine plants. It is shown that for suppressing emissions of the said microcomponents it is necessary to lower temperature in hot local zones of the flame in which NOx is formed, and, in so doing, to avoid chilling of cold flame zones that prevents afterburning of CO. The required lowering of the combustion temperature can be provided by combustion of mixtures of methane with steam, with high mixing uniformity that ensures the same and optimum fraction of the steam "ballast" in each microvolume of the flame. In addition to chilling, the steam ballast makes it possible to maintain a fairly high concentration of hydroxil radicals in the flame zone as well, and this provides high burning out of fuel and reduction in carbon monoxide emissions (active steam ballast). Due to this fact the fraction of steam when firing its mixtures with methane in a gas-turbine plant can be increased up to the weight ratio 4: 1. In this case, the concentrations of NO x and CO in emissions can be reduced to ultra-low values (less than 3 ppm).

  15. High power laser welding in hyperbaric gas and water environments

    SciTech Connect

    Shannon, G.J.; McNaught, W.; Deans, W.F.; Watson, J.

    1997-06-01

    As the exploitation of oil and gas reserves moves into deeper water (>500 m), advanced welding techniques will have to be developed for installation and repair as current commercially available arc welding processes can no longer be utilized at depths greater than 300 m due to the detrimental effect of pressure on arc stability. In addition, systems relying on diver intervention are unlikely to be viable due to health and safety considerations. Here, a hyperbaric laser welding facility has been constructed and the feasibility of high power CO{sub 2} and Nd:YAG laser welding in both high pressure gas and water environments, to simulated water depths of 500 m, has been established. From initial trials on welding through water at atmospheric pressure, it was found that the different absorption characteristics of water to 10.6 {micro}m (CO{sub 2} laser) and 1.06 {micro}m (Nd:YAG laser) radiation proved crucial. The Nd:YAG laser was totally unsuitable as the beam was largely diffused in the water, whereas the CO{sub 2} beam was readily absorbed and, using high speed video equipment, was found to form a high irradiance channel and a dry region around the weld area. Welding under a high pressure gas environment produced a highly energized plume which prevented keyhole welding at pressures over 1 {times} 10{sup 6} Pa. An investigation carried out into the efficacy of a gas jet delivery system to alleviate the extent of the plume showed that argon blown horizontally across the weld was the optimum configuration, extending the welding range up to 5 {times} 10{sup 6} Pa. A limited investigation into high pressure underwater welding showed porosity to be a problem although sound welds were produced at pressures up to 2 {times} 10{sup 6} Pa.

  16. Projecting insect voltinism under high and low greenhouse gas emission conditions.

    PubMed

    Chen, Shi; Fleischer, Shelby J; Tobin, Patrick C; Saunders, Michael C

    2011-06-01

    We develop individual-based Monte Carlo methods to explore how climate change can alter insect voltinism under varying greenhouse gas emissions scenarios by using input distributions of diapause termination or spring emergence, development rate, and diapause initiation, linked to daily temperature and photoperiod. We show concurrence of these projections with a field dataset, and then explore changes in grape berry moth, Paralobesia viteana (Clemens), voltinism that may occur with climate projections developed from the average of three climate models using two different future emissions scenarios from the International Panel of Climate Change (IPCC). Based on historical climate data from 1960 to 2008, and projected downscaled climate data until 2099 under both high (A1fi) and low (B1) greenhouse gas emission scenarios, we used concepts of P. viteana biology to estimate distributions of individuals entering successive generations per year. Under the low emissions scenario, we observed an earlier emergence from diapause and a shift in mean voltinism from 2.8 to 3.1 generations per year, with a fraction of the population achieving a fourth generation. Under the high emissions scenario, up to 3.6 mean generations per year were projected by the end of this century, with a very small fraction of the population achieving a fifth generation. Changes in voltinism in this and other species in response to climate change likely will cause significant economic and ecological impacts, and the methods presented here can be readily adapted to other species for which the input distributions are reasonably approximated.

  17. Characterization of the volatile fraction emitted by phloems of four pinus species by solid-phase microextraction and gas chromatography-mass spectrometry.

    PubMed

    Santos, A M; Vasconcelos, T; Mateus, E; Farrall, M H; Gomes da Silva, M D R; Paiva, M R; Branco, M

    2006-02-10

    Pine forests constitute some of the most important renewable resources supplying timber, paper and chemical industries, among other functions. Characterization of the volatiles emitted by different Pinus species has proven to be an important tool to decode the process of host tree selection by herbivore insects, some of which cause serious economic damage to pines. Variations in the relative composition of the bouquet of semiochemicals are responsible for the outcome of different biological processes, such as mate finding, egg-laying site recognition and host selection. The volatiles present in phloem samples of four pine species, P. halepensis, P. sylvestris, P. pinaster and P. pinea, were identified and characterized with the aim of finding possible host-plant attractants for native pests, such as the bark beetle Tomicus piniperda. The volatile compounds emitted by phloem samples of pines were extracted by headspace solid-phase micro extraction, using a 2cm 50/30mm divinylbenzene/carboxen/polydimethylsiloxane table flex solid-phase microextraction fiber and its contents analyzed by high-resolution gas chromatography, using flame ionization and a non polar and chiral column phases. The components of the volatile fraction emitted by the phloem samples were identified by mass spectrometry using time-of-flight and quadrupole mass analyzers. The estimated relative composition was used to perform a discriminant analysis among pine species, by means of cluster and principal component analysis. It can be concluded that it is possible to discriminate pine species based on the monoterpenes emissions of phloem samples.

  18. High spatial resolution measurements of ram accelerator gas dynamic phenomena

    NASA Technical Reports Server (NTRS)

    Hinkey, J. B.; Burnham, E. A.; Bruckner, A. P.

    1992-01-01

    High spatial resolution experimental tube wall pressure measurements of ram accelerator gas dynamic phenomena are presented. The projectile resembles the centerbody of a ramjet and travels supersonically through a tube filled with a combustible gaseous mixture, with the tube acting as the outer cowling. Pressure data are recorded as the projectile passes by sensors mounted in the tube wall at various locations along the tube. Data obtained by using a special highly instrumented section of tube has allowed the recording of gas dynamic phenomena with a spatial resolution on the order of one tenth the projectile length. High spatial resolution tube wall pressure data from the three regimes of propulsion studied to date (subdetonative, transdetonative, and superdetonative) are presented and reveal the 3D character of the flowfield induced by projectile fins and the canting of the projectile body relative to the tube wall. Also presented for comparison to the experimental data are calculations made with an inviscid, 3D CFD code.

  19. Isotope fractionation in aqua-gas systems: Cl(2)-HCl-Cl(-), Br(2)-HBr-Br(-) and H(2)S-S(2-).

    PubMed

    Czarnacki, Maciej; Hałas, Stanisław

    2012-01-01

    We report calculated values of isotope fractionation factors between chlorine, bromine and sulphide hydrated anions and respective gaseous compounds: hydrogen chloride, hydrogen bromide, molecular chlorine and bromine and hydrogen sulphide. For the calculation of the reduced partition function ratios (β-factors) of hydrated Cl(-), Br(-) and S(2-) anions, we used a model of a cluster composed of the considered ion surrounded by two shells of H(2)O molecules. Only the electrostatic interaction between ion and water molecules treated as electric dipoles was taken into account. The β-factors for the gaseous compounds (HCl, Cl(2), HBr, Br(2) and H(2)S) were calculated from vibrational frequencies reported by Urey and Greiff [Isotopic Exchange Equilibria, J. Am. Chem. Soc. 57, 321 (1935)] and Schauble et al. [Theoretical Estimates Equilibrium Chlorine-Isotope Fractionation, Geochim. Cosmochim. Acta 67, 3267 (2003)]. Low-temperature isotope fractionation between chlorine-hydrated anion and hydrogen chloride attains 1.55-1.68‰ (this work), which is in good agreement with experimental data (1.4-1.8‰) [Z.D. Sharp, J.D. Barnes, T.P. Fischer and M. Halick, An Experimental Determination of Chlorine Isotope Fractionation in Acid Systems and Applications to Volcanic Fumaroles, Geochim. Cosmochim. Acta 74, 264 (2010)]. The predicted isotope fractionations for hydrated bromine and HBr, Br(2) gases are very small, 1000 ln α, do not exceed 0.8‰; thus, the expected variations of bromine isotope composition in aqua-gas systems will require enhanced precision for their detection. In contrast, the sulphur isotope fractionation between H(2)S( gas ) and S(2-) attains 6.0‰ at room temperature and drops nearly linearly to 3.1‰ at 350°C.

  20. Preliminary investigation of a highly sulfated galactofucan fraction isolated from the brown alga Sargassum polycystum.

    PubMed

    Bilan, Maria I; Grachev, Alexey A; Shashkov, Alexander S; Thuy, Thanh Thi Thu; Van, Tran Thi Thanh; Ly, Bui Minh; Nifantiev, Nikolay E; Usov, Anatolii I

    2013-08-09

    A fucoidan preparation was isolated from the brown alga Sargassum polycystum (Fucales, Sargassaceae). The preparation was fractionated by anion-exchange chromatography, and two highly sulfated fractions F3 and F4 were obtained. The fractions were quite similar in composition, but different in chemical structure. F4 was analyzed by chemical methods, including desulfation, methylation, Smith degradation, and partial acid hydrolysis with mass-spectrometric monitoring, as well as by NMR spectroscopy. Several 2D NMR procedures, including HMQC-TOCSY and HMQC-NOESY, were used to obtain reliable structural information from the complex spectra. Molecules of F4 were shown to contain a backbone built up mainly of 3-linked α-L-fucopyranose 4-sulfate residues, as in many other fucoidans, but rather short sequences of these residues are interspersed by single 2-linked α-D-galactopyranose residues also sulfated at position 4. This rather unusual structural feature should have a great influence on the conformation of the polymeric molecule and may be important for biological activity of the polysaccharide. Hence, F4 is an example of a new sulfated galactofucan isolated from the brown alga. According to the data obtained, the distribution of galactose residues along the polysaccharide backbone seems to be not strictly regular, but the definitive sequence of monomers in the polymeric molecules awaits additional investigation.

  1. Rapid screening of polar compounds in Brazilian propolis by high-temperature high-resolution gas chromatography-mass spectrometry.

    PubMed

    Pereira, A S; Norsell, M; Cardoso, J N; Aquino Neto, F R; Ramos, M F

    2000-11-01

    Methanol extracts of propolis from six different places, five in Rio de Janeiro state and one in São Paulo state, both in the Southeast of Brazil, were investigated using high-temperature high-resolution gas chromatography (HT-HRGC) and HT-HRGC-mass spectometry. The main purpose of the study was to establish the applicability of HT-HRGC as an analytical method for systematic studies of polar propolis fractions. Several compounds, including carbohydrates, phenolic acid derivatives, and high molecular weight compounds (e.g., wax esters of long chain fatty alcohols) could be readily characterized in the crude extracts by HT-HRGC-MS. HT-HRGC and HT-HRGC-MS were shown to be quick and informative tools for rapid analysis of crude polar extracts without cleanup.

  2. Determination of gas-trapping during high frequency oscillatory ventilation.

    PubMed

    Alexander, J; Milner, A D

    1997-03-01

    To determine the effect of frequency and percent inspiratory time on tidal volume and gas-trapping during high-frequency oscillatory ventilation (HFOV). Nine preterm infants with respiratory distress syndrome tested in the first 48 h of life. Tidal volumes and the presence of gas-trapping were measured by respiratory jacket plethysmography at frequencies of 10, 14, and 17.8 Hz and at inspiratory times of 30%, 50% and 70%, using a commercially available high frequency oscillator.74 Mean (SD) tidal volumes were 2.40 (1.06) ml/kg at 10 Hz, 2.52 (1.07) ml/kg at 14 Hz and fell significantly to 1.96 (0.92) at 17.8 Hz (p < 0.05). Tidal volumes at 50% inspiratory time were significantly greater than at 30% inspiratory time [2.81 (1.42) ml/kg and 2.32 (1.18) ml/kg, respectively] but fell to baseline levels at 70% inspiratory time. There was no significant gas-trapping with increases in either frequency or percent inspiratory time. Gas-trapping is not a significant problem during HFOV in premature infants. Changes in tidal volume with increases in frequency and percent inspiratory time are similar to that seen in animal models.

  3. Land-use intensification impact on phosphorus fractions in highly weathered tropical soils

    NASA Astrophysics Data System (ADS)

    Maranguit, Deejay; Guillaume, Thomas; Kuzyakov, Yakov

    2016-04-01

    Deforestation and land-use intensification in tropics have increased over the past decades, driven by the demand for agricultural products. Despite the fact that phosphorus (P) is one of the main limiting nutrients for agricultural productivity in the tropics, the effect of land-use intensification on P availability remains unclear. The objective was to assess the impacts of land-use intensification on soil inorganic and organic P fractions of different availability (Hedley sequential fractionation) and P stocks in highly weathered tropical soils. We compared the P availability under extensive land-use (rubber agroforest) and intensive land-use with moderate fertilization (rubber monoculture plantations) or high fertilization (oil palm monoculture plantations) in Indonesia. The phosphorus stock was dominated by inorganic forms (60 to 85%) in all land-use types. Fertilizer application increased easily-available inorganic P (i.e., H2O-Pi, NaHCO3-Pi) in intensive rubber and oil palm plantations compared to agroforest. However, the easily-available organic P (NaHCO3-extractable Po) was reduced by half under oil palm and rubber. The decrease of moderately available and non-available P by land-use intensification means that fertilization maintains only short-term soil fertility that is not sustainable in the long run due to the depletion of P reserves. The mechanisms of this P reserve depletion are: soil erosion (here assessed by C/P ratio), mineralization of soil organic matter (SOM) and export of P with yield products. Easily-available P fractions (i.e., H2O-Pi, NaHCO3-Pi and Po) and total organic P were strongly positively correlated with carbon content suggesting that SOM plays a critical role in maintaining P availability. Therefore, the ecologically based management is necessary in mitigating SOM losses to increase the sustainability of agricultural production in P limited highly weathered tropical soils.

  4. Iron isotope fractionation in subduction-related high-pressure metabasites (Ile de Groix, France)

    NASA Astrophysics Data System (ADS)

    El Korh, Afifé; Luais, Béatrice; Deloule, Etienne; Cividini, Damien

    2017-06-01

    Characterisation of mass transfer during subduction is fundamental to understand the origin of compositional heterogeneities in the upper mantle. Fe isotopes were measured in high-pressure/low-temperature metabasites (blueschists, eclogites and retrograde greenschists) from the Ile de Groix (France), a Variscan high-pressure terrane, to determine if the subducted oceanic crust contributes to mantle Fe isotope heterogeneities. The metabasites have δ56Fe values of +0.16 to +0.33‰, which are heavier than typical values of MORB and OIB, indicating that their basaltic protolith derives from a heavy-Fe mantle source. The δ56Fe correlates well with Y/Nb and (La/Sm)PM ratios, which commonly fractionate during magmatic processes, highlighting variations in the magmatic protolith composition. In addition, the shift of δ56Fe by +0.06 to 0.10‰ compared to basalts may reflect hydrothermal alteration prior to subduction. The δ56Fe decrease from blueschists (+0.19 ± 0.03 to +0.33 ± 0.01‰) to eclogites (+0.16 ± 0.02 to +0.18 ± 0.03‰) reflects small variations in the protolith composition, rather than Fe fractionation during metamorphism: newly-formed Fe-rich minerals allowed preserving bulk rock Fe compositions during metamorphic reactions and hampered any Fe isotope fractionation. Greenschists have δ56Fe values (+0.17 ± 0.01 to +0.27 ± 0.02‰) similar to high-pressure rocks. Hence, metasomatism related to fluids derived from the subducted hydrothermally altered metabasites might only have a limited effect on mantle Fe isotope composition under subsolidus conditions, owing to the large stability of Fe-rich minerals and low mobility of Fe. Subsequent melting of the heavy-Fe metabasites at deeper levels is expected to generate mantle Fe isotope heterogeneities.

  5. High integrity adaptive SMA components for gas turbine applications

    NASA Astrophysics Data System (ADS)

    Webster, John

    2006-03-01

    The use of Shape Memory Alloys (SMAs) is growing rapidly. They have been under serious development for aerospace applications for over 15 years, but are still restricted to niche areas and small scale applications. Very few applications have found their way into service. Whilst they have been predominantly aimed at airframe applications, they also offer major advantages for adaptive gas turbine components. The harsh environment within a gas turbine with its high loads, temperatures and vibration excitation provide considerable challenges which must be met whilst still delivering high integrity, light weight, aerodynamic and efficient structures. A novel method has been developed which will deliver high integrity, stiff mechanical components which can provide massive shape change capability without the need for conventional moving parts. The lead application is for a shape changing engine nozzle to provide noise reduction at take off but will withdraw at cruise to remove any performance penalty. The technology also promises to provide significant advantages for applications in a gas turbine such as shape change aerofoils, heat exchanger controls, and intake shapes. The same mechanism should be directly applicable to other areas such as air frames, automotive and civil structures, where similar high integrity requirements exist.

  6. Ca isotope fractionation in a high-alkalinity lake system: Mono Lake, California

    NASA Astrophysics Data System (ADS)

    Nielsen, Laura C.; DePaolo, Donald J.

    2013-10-01

    Precipitation of calcium carbonate minerals from aqueous solutions causes surface-controlled kinetic stable Ca isotope fractionation. The magnitude of fractionation depends on the relative rates of ion attachment to and detachment from the mineral surface, which in turn is predicted to depend on both the saturation state and the solution stoichiometry or the Ca:CO32- activity ratio. Experimental studies have not directly investigated the effects of varying solution stoichiometry on calcium isotope partitioning during calcite or aragonite growth, but natural alkaline lake systems such as Mono Lake, California provide a test bed for the hypothesized stoichiometry dependence. Mono Lake has a Ca:CO32- activity ratio of about 0.0001, seven orders of magnitude lower than ocean water and typical terrestrial freshwater. We present chemical and isotopic measurements of streams, springs, lake water, and precipitated carbonates from the Mono Basin that yield evidence of stoichiometry-dependent Ca isotope fractionation during calcite, aragonite and Mg-calcite precipitation from the alkaline lake water. To estimate the Ca isotope fractionation factors, it is necessary to characterize the lake Ca balance and constrain the variability of lake water chemistry both spatially and temporally. Streams and springs supply Ca to the lake, and a substantial fraction of this supply is precipitated along the lake shore to form tufa towers. Lake water is significantly supersaturated with respect to carbonate minerals, so CaCO3 also precipitates directly from the water column to form carbonate-rich bottom sediments. Growth rate inhibition by orthophosphate likely preserves the high degree of supersaturation in the lake. Strontium isotope ratios are used to estimate the proportions of fresh and alkaline lake water from which each solid carbonate sample precipitated. Carbonate minerals that precipitate directly from lake water (low Ca:CO32-) experience relatively large Ca isotope fractionation

  7. Study on the purification of hydrogen bromide gas by fractional distillation technique and its effect on improvement of copper-hydrogen bromide laser performance

    NASA Astrophysics Data System (ADS)

    Biswal, Ramakanta; Agrawal, Praveen Kumar; Dixit, Sudhir K.; Nakhe, Shankar V.

    2012-11-01

    This paper presents a purification process of hydrogen bromide (HBr) gas by fractional distillation technique and its use for performance enhancement of copper-HBr laser (Cu-HBrL). The residual impurities in HBr were suppressed by a two-step distillation process at temperatures of -196°C and -20°C. The lowering of the impurities was confirmed by comparing the mass spectrograph of the HBr gas before and after distillation, using a quadrupole mass spectrometer. The effect of the purified HBr gas on the performance of Cu-HBrL average output power as well its electrical discharge characteristics were studied. More than 37% improvement in the laser average output power (40 to 55 W) was observed with the use of this distilled HBr gas compared to undistilled gas. The underlying mechanism of the enhancement was analyzed by comparing electrical discharge characteristics in the two cases. The improvement in Cu-HBrL performance with distilled HBr gas was attributed to lowering of bromine and hydrogen concentration, mainly manifested as increased average electrical energy coupling to the discharge. This resulted in increased laser gain as well as gain volume, which were reflected in increases in laser output power and beam diameter.

  8. Possible hypoglycemic effect of Aloe vera L. high molecular weight fractions on type 2 diabetic patients.

    PubMed

    Yagi, Akira; Hegazy, Sahar; Kabbash, Amal; Wahab, Engy Abd-El

    2009-07-01

    Aloe vera L. high molecular weight fractions (AHM) containing less than 10 ppm of barbaloin and polysaccharide (MW: 1000 kDa) with glycoprotein, verectin (MW: 29 kDa), were prepared by patented hyper-dry system in combination of freeze-dry technique with microwave and far infrared radiation. AHM produced significant decrease in blood glucose level sustained for 6 weeks of the start of the study. Significant decrease in triglycerides was only observed 4 weeks after treatment and continued thereafter. No deterious effects on kidney and liver functions were apparent. Treatment of diabetic patients with AHM may relief vascular complications probably via activation of immunosystem.

  9. Constraining cloud parameters using high density gas tracers in galaxies

    NASA Astrophysics Data System (ADS)

    Kazandjian, M. V.; Pelupessy, I.; Meijerink, R.; Israel, F. P.; Coppola, C. M.; Rosenberg, M. J. F.; Spaans, M.

    2016-11-01

    Far-infrared molecular emission is an important tool used to understand the excitation mechanisms of the gas in the interstellar medium (ISM) of star-forming galaxies. In the present work, we model the emission from rotational transitions with critical densities n ≳ 104 cm-3. We include 4-3 < J ≤ 15-14 transitions of CO and 13CO , in addition to J ≤ 7-6 transitions of HCN, HNC, and HCO+ on galactic scales. We do this by re-sampling high density gas in a hydrodynamic model of a gas-rich disk galaxy, assuming that the density field of the ISM of the model galaxy follows the probability density function (PDF) inferred from the resolved low density scales. We find that in a narrow gas density PDF, with a mean density of 10 cm-3 and a dispersion σ = 2.1 in the log of the density, most of the emission of molecular lines, even of gas with critical densities >104 cm-3, emanates from the 10-1000 cm-3 part of the PDF. We construct synthetic emission maps for the central 2 kpc of the galaxy and fit the line ratios of CO and 13CO up to J = 15-14, as well as HCN, HNC, and HCO+ up to J = 7-6, using one photo-dissociation region (PDR) model. We attribute the goodness of the one component fits for our model galaxy to the fact that the distribution of the luminosity, as a function of density, is peaked at gas densities between 10 and 1000 cm-3, with negligible contribution from denser gas. Specifically, the Mach number, ℳ, of the model galaxy is 10. We explore the impact of different log-normal density PDFs on the distribution of the line-luminosity as a function of density, and we show that it is necessary to have a broad dispersion, corresponding to Mach numbers ≳30 in order to obtain significant (>10%) emission from n> 104 cm-3 gas. Such Mach numbers are expected in star-forming galaxies, luminous infrared galaxies (LIRGS), and ultra-luminous infrared galaxies (ULIRGS). This method provides a way to constrain the global PDF of the ISM of galaxies from observations of

  10. PROBING THE PHYSICAL CONDITIONS OF ATOMIC GAS AT HIGH REDSHIFT

    SciTech Connect

    Neeleman, Marcel; Wolfe, Arthur M.; Prochaska, J. Xavier

    2015-02-10

    A new method is used to measure the physical conditions of the gas in damped Lyα systems (DLAs). Using high-resolution absorption spectra of a sample of 80 DLAs, we are able to measure the ratio of the upper and lower fine-structure levels of the ground state of C{sup +} and Si{sup +}. These ratios are determined solely by the physical conditions of the gas. We explore the allowed physical parameter space using a Monte Carlo Markov chain method to constrain simultaneously the temperature, neutral hydrogen density, and electron density of each DLA. The results indicate that at least 5% of all DLAs have the bulk of their gas in a dense, cold phase with typical densities of ∼100 cm{sup –3} and temperatures below 500 K. We further find that the typical pressure of DLAs in our sample is log (P/k{sub B} ) = 3.4 (K cm{sup –3}), which is comparable to the pressure of the local interstellar medium (ISM), and that the components containing the bulk of the neutral gas can be quite small with absorption sizes as small as a few parsecs. We show that the majority of the systems are consistent with having densities significantly higher than expected for a purely canonical warm neutral medium, indicating that significant quantities of dense gas (i.e., n {sub H} > 0.1 cm{sup –3}) are required to match observations. Finally, we identify eight systems with positive detections of Si II*. These systems have pressures (P/k{sub B} ) in excess of 20,000 K cm{sup –3}, which suggest that these systems tag a highly turbulent ISM in young, star-forming galaxies.

  11. Analysis of unsteady natural convective radiating gas flow in a vertical channel by employing the Caputo time-fractional derivative

    NASA Astrophysics Data System (ADS)

    Ahmad, Bakhtiar; Ali Shah, Syed Inayat; Ul Haq, Sami; Ali Shah, Nehad

    2017-09-01

    In this paper the exact solution of the unsteady natural convection radiating flow in an open ended vertical channel is studied. The channel is stationary with non-uniform temperature. The governing equations are fractional differential equations with the Caputo time-fractional derivative. Closed form analytical solutions for the temperature and velocity fields are obtained by using the Laplace transform technique. These solutions are expressed with the Wright function, the Robotnov and Hartley function. The effects of the fractional order and physical parameters on temperature and fluid velocity are presented graphically.

  12. ULTRASENSITIVE HIGH-TEMPERATURE SELECTIVE GAS DETECTION USING PIEZOELECTRIC MICROCANTILEVERS

    SciTech Connect

    Wan Y. Shih; Tejas Patil; Qiang Zhao; Yi-Shi Chiu; Wei-Heng Shih

    2004-03-05

    We have obtained very promising results in the Phase I study. Specifically, for temperature effects, we have established that piezoelectric cantilever sensors could retain their resonance peak strength at high temperatures, i.e., the Q values of the resonance peaks remained above 10 even when the temperature was very close to the Curie temperature. This confirms that a piezoelectric cantilever sensor can be used as a sensor up to its Curie temperature. Furthermore, we have shown that the mass detection sensitivity remained unchanged at different temperatures. For selective gas detection, we have demonstrated selective NH{sub 3} detection using piezoelectric cantilever sensors coated with mesoporous SiO{sub 2}. For high-temperature sensor materials development, we have achieved highly oriented Sr-doped lead titanate thin films that possessed superior dielectric and ferroelectric properties. Such highly oriented films can be microfabricated into high-performance piezoelectric microcantilever sensors that can be used up to 490 C. We have accomplished the goal of Phase I study in exploring the various aspects of a high-temperature gas sensor. We propose to continue the study in Phase II to develop a sensor that is suitable for high-temperature applications using piezoelectrics with a high Curie temperature and by controlling the effects of temperature. The lead titanate based thin film developed in Phase I is good for applications up to 490 C. In phase II, we will develop lithium niobate thin film based cantilevers for applications up to 1000 C.

  13. Sample handling and contamination encountered when coupling offline normal phase high performance liquid chromatography fraction collection of petroleum samples to Fourier transform ion cyclotron resonance mass spectrometry.

    PubMed

    Oro, Nicole E; Whittal, Randy M; Lucy, Charles A

    2012-09-05

    Normal phase high performance liquid chromatography (HPLC) is used to separate a gas oil petroleum sample, and the fractions are collected offline and analyzed on a high resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometer (FT-ICR MS). The separation prior to MS analysis dilutes the sample significantly; therefore the fractions need to be prepared properly to achieve the best signal possible. The methods used to prepare the HPLC fractions for MS analysis are described, with emphasis placed on increasing the concentration of analyte species. The dilution effect also means that contamination in the MS spectra needs to be minimized. The contamination from molecular sieves, plastics, soap, etc. and interferences encountered during the offline fraction collection process are described and eliminated. A previously unreported MS contamination of iron formate clusters with a 0.8 mass defect in positive mode electrospray is also described. This interference resulted from the stainless steel tubing in the HPLC system. Contamination resulting from what has tentatively been assigned as palmitoylglycerol and stearoylglycerol was also observed; these compounds have not previously been reported as contaminant peaks. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Scaling of multiphase pipeline flow behavior at high gas density

    SciTech Connect

    Crowley, C.J.

    1988-01-01

    This report contains data that demonstrates the scaling of flow regime, pressure drop, and holdup multiphase flow with pipe diameter. In addition, entrance length effects, the onset of liquid entrainment, and interfacial shear modeling at high gas density are studied for purposes of validating multiphase flow design methods. Stratified, slug and annular flow regimes have been observed. Air, freon, and water have been used to represent pipeline fluids.

  15. High-Temperature Gas-Cooled Test Reactor Point Design

    SciTech Connect

    Sterbentz, James William; Bayless, Paul David; Nelson, Lee Orville; Gougar, Hans David; Kinsey, James Carl; Strydom, Gerhard; Kumar, Akansha

    2016-04-01

    A point design has been developed for a 200 MW high-temperature gas-cooled test reactor. The point design concept uses standard prismatic blocks and 15.5% enriched UCO fuel. Reactor physics and thermal-hydraulics simulations have been performed to characterize the capabilities of the design. In addition to the technical data, overviews are provided on the technological readiness level, licensing approach and costs.

  16. Geothermal Well Stimulated Using High Energy Gas Fracturing

    SciTech Connect

    Chu, T.Y.; Jacobson, R.D.; Warpinski, N.; Mohaupt, Henry

    1987-01-20

    This paper reports the result of an experimental study of the High Energy Gas Fracturing (HEGF) technique for geothermal well stimulation. These experiments demonstrated that multiple fractures could be created to link a water-filled borehole with other fractures. The resulting fracture network and fracture interconnections were characterized by flow tests as well as mine back. Commercial oil field fracturing tools were used successfully in these experiments. 5 refs., 2 tabs., 5 figs.

  17. Gentle protein ionization assisted by high-velocity gas flow.

    PubMed

    Yang, Pengxiang; Cooks, R Graham; Ouyang, Zheng; Hawkridge, Adam M; Muddiman, David C

    2005-10-01

    Gentle protein electrospray ionization is achieved using the high-velocity gas flow of an air amplifier to improve desolvation in conventional ESI and generate intact folded protein ions in the gas phase. Comparisons are made between the ESI spectra of a number of model proteins, including ubiquitin, cytochrome c, lysozyme, and myoglobin, over a range of pH values under optimized conditions, with and without using an air amplifier to achieve high-velocity gas flow. Previously reported increased ion signals are confirmed. In addition, the peaks recorded using the air amplifier are shown to be narrower, corresponding to more complete desolvation. Significant changes in the charge-state distribution also are observed, with a shift to lower charge state at high-velocity flow. The relationship between the observed charge-state distribution and protein conformation was explored by comparing the charge-state shifts and the distributions of charge states for proteins that are or are not stable in their native conformations in low pH solutions. The data suggest retention of native or nativelike protein conformations using the air amplifier in all cases examined. This is explained by a mechanism in which the air amplifier rapidly creates small droplets from the original large ESI droplets and these microdroplets then desolvate without a significant decrease in pH, resulting in retention of the folded protein conformations. Furthermore, the holoform of ionized myoglobin is visible at pH 3.5, a much lower value than the minimum needed to see this form in conventional ESI. These results provide evidence for the importance of the conditions used in the desolvation process for the preservation of the protein conformation and suggest that the conditions achieved when using high-velocity gas flows to assist droplet evaporation and ion desolvation are much gentler than those in conventional ESI experiments.

  18. Fractionated exposure of high energy iron ions has a sparing effect in vivo

    NASA Astrophysics Data System (ADS)

    Chang, P. Y.; Bakke, J.; Puey, A.

    The radiation environment in deep space is complex and includes a broad spectrum of charged and highly energetic particle radiations. Exposure to these types of radiations may pose potential health risks in manned space missions. The detection of particle radiation-induced genomic alterations in vivo, particularly in slow or non-dividing tissues, is therefore important to provide relevant information in estimating risks. We are using a plasmid-based lacZ transgenic mouse model system to rapidly measure, in a statistically reliable way, the mutagenic potential of charged particle radiations relevant in the space environment. The lacZ transgenic mouse has been constructed so that every cell of the animal contains multiple copies of an integrated target reporter gene, allowing us to measure tissue-specific radiation-induced changes as a function of dosing regime. The nature of these mutations can also be characterized by restriction fragment length polymorphisms (RFLP). To examine the impact of dose protraction, animals were exposed to a single dose or daily fractions of 1 GeV/n iron ions. Cytotoxicity in the peripheral blood was measured by enumerating the frequency of circulating micronucleated reticulocytes (fMN-RET) in a time course from 24 h up to 1 week after completion of the radiation protocol. Brain and spleen tissues were harvested at 8 weeks after exposure and mutant frequencies (MF) in the transgene in these tissues were measured. Results from the fractionated protocol were compared to the responses obtained after the animals were exposed to the single dose treatment. We noted significantly lower levels of micronucleated reticulocytes in peripheral blood at 48 h after fractionated doses of iron ions when compared to the same total dose delivered in a single exposure demonstrating that protracted exposures of particle radiation resulted in an overall sparing effect in cytogenetic toxicity in the hematopoietic system in animals. Transgene mutation analysis

  19. Development of a vaccine to mitigate greenhouse gas emissions in agriculture: vaccination of sheep with methanogen fractions induces antibodies that block methane production in vitro.

    PubMed

    Wedlock, D N; Pedersen, G; Denis, M; Dey, D; Janssen, P H; Buddle, B M

    2010-02-01

    To develop an understanding of the immune responses of ruminants to methanogens, and to provide proof of a concept that harnessing the immune system of ruminants is a potentially viable approach to mitigate greenhouse gas emissions from agriculture. Four subcellular fractions, namely cytoplasmic, two cell-wall preparations, and cell wall-derived proteins were prepared from Methanobrevibacter ruminantium M1. Twenty sheep (10 months of age) were vaccinated with these fractions or with whole cells (n=4 per group). Sheep were re-vaccinated once after 3 weeks, and antibody responses to M. ruminantium M1 antigens in sera and saliva measured using ELISA at 2 weeks after the second vaccination. Antigens recognised by the antisera were visualised using Western blotting. The antisera were tested in vitro for their impact on M. ruminantium M1, measuring the effect on cell growth, methane production, and ability to induce agglutination. Basal levels (pre-vaccination) of antibodies against M. ruminantium M1 antigens were low. Vaccination with the antigenic fractions induced strong antibody responses in serum. Both IgG and IgA responses to methanogen antigens were detected in saliva following vaccination. Western blot analysis of the antisera indicated reactivity of antibodies, and a wide range of proteins was present in the different methanogen fractions. Antisera against the various fractions agglutinated methanogens in an in-vitro assay. In addition, these antisera decreased the growth of a pure culture of a methanogen and production of methane in vitro. Antigens from methanogens are immunogenic in ruminants, and antisera from sheep vaccinated with fractions of methanogens have a significant impact on these organisms, inducing cell agglutination, and decreasing growth of methanogens and production of methane. Only antisera to selected methanogen fractions were able to achieve these effects. The results demonstrate the feasibility of a vaccination strategy to mitigate emission

  20. Exploration for unknown substances in rapeseed oil that shorten survival time of stroke-prone spontaneously hypertensive rats. Effects of super critical gas extraction fractions.

    PubMed

    Ohara, Naoki; Naito, Yukiko; Nagata, Tomoko; Tatematsu, Kenjiro; Fuma, Shin-Ya; Tachibana, Shigehiro; Okuyama, Harumi

    2006-07-01

    To identify the causative substances for the shortening of survival time by rapeseed (Canola) oil in stroke-prone spontaneously hypertensive rats (SHRSP), SHRSP were fed on a standard chow supplemented with 10 w/w% soybean oil (control), rapeseed oil, one of the fractions of rapeseed oil obtained by super critical gas extraction (SCE) under a pressure of 180-bar or 350-bar, at 40 degrees C, or the residue from the extraction (with 0.5% NaCl in drinking water). In another series of experiment, SHRSP were fed for 8 weeks on the above-mentioned diets without salt loading and autopsied. Fatty acid compositions in these diets were similar, except in the soybean oil diet, and phytosterol contents were: (diet containing) 180-bar fraction>residue>rapeseed oil>350-bar fraction>soybean oil. Survival times in the rapeseed oil, 350-bar fraction and residue groups were shorter than, whereas that in the 180-bar fraction was similar to in the soybean oil group. In the 8-week feeding experiment, chronic nephropathy was found frequently in the groups other than the soybean oil group. The heart weights were higher in the rapeseed oil and residue groups. Cerebral necrosis was found in the residue group. Taken together, the followings are concluded, (1) Neither the fatty acid composition, nor the amount of phytosterols in the diets appeared to be decisive in the shortening of life. (2) SCE appeared to produce a safe (180-bar) fraction, though it failed to separate clearly the causative substances into specific fractions. (3) The factors that facilitate the genetic disease of SHRSP appear to exist in rapeseed oil. However, they might not be identical to those responsible for the life-shortening, since there were no findings common across the rapeseed oil, 350-bar and residue groups, which showed similar life-shortening.

  1. Scintillation luminescence for high-pressure xenon gas

    NASA Astrophysics Data System (ADS)

    Kobayashi, S.; Hasebe, N.; Igarashi, T.; Kobayashi, M.-N.; Miyachi, T.; Miyajima, M.; Okada, H.; Okudaira, O.; Tezuka, C.; Yokoyama, E.; Doke, T.; Shibamura, E.; Dmitrenko, V. V.; Ulin, S. E.; Vlasik, K. F.

    2004-09-01

    Scintillation and ionization yields in xenon gas for 5.49MeV alpha-particles were measured in the range of pressure from 0.35 to 3.7MPa and the electric field strength (E) over the number density of xenon atoms (N), E/N from 0 to 5×10-18Vcm2. When our data are normalized at the data point measured by Saito et al., the number of scintillation photons is 2.3×105 while the number of ionization electrons is 2.0×105 at 2.6MPa and at 3.7×10-18Vcm2. The scintillation and ionization yields of xenon doped with 0.2% hydrogen, High-Pressure Xenon gas[H2-0.2%], at 2.6MPa was also measured. Scintillation yield of the Xe-H2 mixture gas is 80% as high as that of pure xenon. It is found that the scintillation yield is luminous enough to generate a trigger pulse of the high-pressure xenon time projection chamber, which is expected as a promising MeV Compton gamma-ray camera.

  2. Feeding cosmic star formation: exploring high-redshift molecular gas with CO intensity mapping

    NASA Astrophysics Data System (ADS)

    Breysse, Patrick C.; Rahman, Mubdi

    2017-06-01

    The study of molecular gas is crucial for understanding star formation, feedback and the broader ecosystem of a galaxy as a whole. However, we have limited understanding of its physics and distribution in all but the nearest galaxies. We present a new technique for studying the composition and distribution of molecular gas in high-redshift galaxies inaccessible to existing methods. Our proposed approach is an extension of carbon monoxide intensity mapping methods, which have garnered significant experimental interest in recent years. These intensity mapping surveys target the 115 GHz 12CO (1-0) line, but also contain emission from the substantially fainter 110 GHz 13CO (1-0) transition. The method leverages the information contained in the 13CO line by cross-correlating pairs of frequency channels in an intensity mapping survey. Since 13CO is emitted from the same medium as the 12CO, but saturates at a much higher column density, this cross-correlation provides valuable information about both the gas density distribution and isotopologue ratio, inaccessible from the 12CO alone. Using a simple model of these molecular emission lines, we show that a future intensity mapping survey can constrain the abundance ratio of these two species and the fraction of emission from optically thick regions to order ˜30 per cent. These measurements cannot be made by traditional CO observations, and consequently the proposed method will provide unique insight into the physics of star formation, feedback and galactic ecology at high redshifts.

  3. Iron isotopic fractionation between silicate mantle and metallic core at high pressure

    PubMed Central

    Liu, Jin; Dauphas, Nicolas; Roskosz, Mathieu; Hu, Michael Y.; Yang, Hong; Bi, Wenli; Zhao, Jiyong; Alp, Esen E.; Hu, Justin Y.; Lin, Jung-Fu

    2017-01-01

    The +0.1‰ elevated 56Fe/54Fe ratio of terrestrial basalts relative to chondrites was proposed to be a fingerprint of core-mantle segregation. However, the extent of iron isotopic fractionation between molten metal and silicate under high pressure–temperature conditions is poorly known. Here we show that iron forms chemical bonds of similar strengths in basaltic glasses and iron-rich alloys, even at high pressure. From the measured mean force constants of iron bonds, we calculate an equilibrium iron isotope fractionation between silicate and iron under core formation conditions in Earth of ∼0–0.02‰, which is small relative to the +0.1‰ shift of terrestrial basalts. This result is unaffected by small amounts of nickel and candidate core-forming light elements, as the isotopic shifts associated with such alloying are small. This study suggests that the variability in iron isotopic composition in planetary objects cannot be due to core formation. PMID:28216664

  4. Profiling the main cell wall polysaccharides of grapevine leaves using high-throughput and fractionation methods.

    PubMed

    Moore, John P; Nguema-Ona, Eric; Fangel, Jonatan U; Willats, William G T; Hugo, Annatjie; Vivier, Melané A

    2014-01-01

    Vitis species include Vitis vinifera, the domesticated grapevine, used for wine and grape agricultural production and considered the world's most important fruit crop. A cell wall preparation, isolated from fully expanded photosynthetically active leaves, was fractionated via chemical and enzymatic reagents; and the various extracts obtained were assayed using high-throughput cell wall profiling tools according to a previously optimized and validated workflow. The bulk of the homogalacturonan-rich pectin present was efficiently extracted using CDTA treatment, whereas over half of the grapevine leaf cell wall consisted of vascular veins, comprised of xylans and cellulose. The main hemicellulose component was found to be xyloglucan and an enzymatic oligosaccharide fingerprinting approach was used to analyze the grapevine leaf xyloglucan fraction. When Paenibacillus sp. xyloglucanase was applied the main subunits released were XXFG and XLFG; whereas the less-specific Trichoderma reesei EGII was also able to release the XXXG motif as well as other oligomers likely of mannan and xylan origin. This latter enzyme would thus be useful to screen for xyloglucan, xylan and mannan-linked cell wall alterations in laboratory and field grapevine populations. This methodology is well-suited for high-throughput cell wall profiling of grapevine mutant and transgenic plants for investigating the range of biological processes, specifically plant disease studies and plant-pathogen interactions, where the cell wall plays a crucial role. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Ultrasonic atomization of tissue and its role in tissue fractionation by high intensity focused ultrasound

    PubMed Central

    Simon, Julianna C.; Sapozhnikov, Oleg A.; Khokhlova, Vera A.; Wang, Yak-Nam; Crum, Lawrence A.; Bailey, Michael R.

    2012-01-01

    Atomization and fountain formation is a well-known phenomenon that occurs when a focused ultrasound wave in liquid encounters an air interface. High intensity focused ultrasound (HIFU) has been shown to fractionate tissue into submicron-size fragments in a process termed boiling histotripsy, wherein the focused ultrasound wave superheats the tissue at the focus, producing a millimetre-size boiling or vapour bubble in several milliseconds. Yet the question of how this millimetre-size boiling bubble creates submicron-size tissue fragments remains. The hypothesis of this work is that tissue can behave as a liquid such that it forms a fountain and atomization within the vapour bubble produced in boiling histotripsy. We describe an experiment, in which a 2-MHz HIFU transducer (maximum in situ intensity of 24,000 W/cm2) was aligned with an air-tissue interface meant to simulate the boiling bubble. Atomization and fountain formation were observed with high-speed photography and resulted in tissue erosion. Histological examination of the atomized tissue showed whole and fragmented cells and nuclei. Air-liquid interfaces were also filmed. Our conclusion was that HIFU can fountain and atomize tissue. Although this process does not entirely mimic what was observed in liquids, it does explain many aspects of tissue fractionation in boiling histotripsy. PMID:23159812

  6. Ultrasonic atomization of tissue and its role in tissue fractionation by high intensity focused ultrasound

    NASA Astrophysics Data System (ADS)

    Simon, Julianna C.; Sapozhnikov, Oleg A.; Khokhlova, Vera A.; Wang, Yak-Nam; Crum, Lawrence A.; Bailey, Michael R.

    2012-12-01

    Atomization and fountain formation is a well-known phenomenon that occurs when a focused ultrasound wave in liquid encounters an air interface. High intensity focused ultrasound (HIFU) has been shown to fractionate a tissue into submicron-sized fragments in a process termed boiling histotripsy, wherein the focused ultrasound wave superheats the tissue at the focus, producing a millimetre-sized boiling or vapour bubble in several milliseconds. Yet the question of how this millimetre-sized boiling bubble creates submicron-sized tissue fragments remains. The hypothesis of this work is that the tissue can behave as a liquid such that it atomizes and forms a fountain within the vapour bubble produced in boiling histotripsy. We describe an experiment, in which a 2 MHz HIFU transducer (maximum in situ intensity of 24 000 W cm-2) was aligned with an air-tissue interface meant to simulate the boiling bubble. Atomization and fountain formation was observed with high-speed photography and resulted in tissue erosion. Histological examination of the atomized tissue showed whole and fragmented cells and nuclei. Air-liquid interfaces were also filmed. Our conclusion was that HIFU can fountain and atomize tissue. Although this process does not entirely mimic what was observed in liquids, it does explain many aspects of tissue fractionation in boiling histotripsy.

  7. Internal filtration, filtration fraction, and blood flow resistance in high- and low-flux dialyzers.

    PubMed

    Schneditz, Daniel; Zierler, Edda; Vanholder, Raymond; Eloot, Sunny

    2014-01-01

    It was the aim to examine the fluid flow in blood and dialysate compartments of highly permeable hollow fiber dialyzers where internal filtration contributes to solute removal but where excessive filtration bears a risk of cell activation and damage. Flow characteristics of high- (HF) and low-flux (LF) dialyzers were studied in lab-bench experiments using whole bovine blood. Measurements obtained under different operating conditions and under zero net ultrafiltration were compared to theoretical calculations obtained from a mathematical model. Experimental resistances in the blood compartment were within ±2% of those calculated from the model when dialysate was used as a test fluid. With whole blood, the experimental resistances in the blood compartment were only 81.8 ± 2.8% and 83.7 ± 4.3% of those calculated for the LF and HF dialyzer, respectively. Surprisingly, measured blood flow resistance slightly but significantly decreased with increasing flow rate (p < 0.001). Mathematical modeling confirmed this decrease both in LF and HF dialyzers which was accompanied by a concomitant decrease in internal filtration fraction, while overall internal filtration increased. The increase in internal filtration when increasing blood flow is associated with a beneficial reduction in internal filtration fraction. Concerns of increased hemoconcentration when increasing blood flow therefore appear to be unwarranted.

  8. Extreme Ultraviolet Fractional Orbital Angular Momentum Beams from High Harmonic Generation

    PubMed Central

    Turpin, Alex; Rego, Laura; Picón, Antonio; San Román, Julio; Hernández-García, Carlos

    2017-01-01

    We investigate theoretically the generation of extreme-ultraviolet (EUV) beams carrying fractional orbital angular momentum. To this end, we drive high-order harmonic generation with infrared conical refraction (CR) beams. We show that the high-order harmonic beams emitted in the EUV/soft x-ray regime preserve the characteristic signatures of the driving beam, namely ringlike transverse intensity profile and CR-like polarization distribution. As a result, through orbital and spin angular momentum conservation, harmonic beams are emitted with fractional orbital angular momentum, and they can be synthesized into structured attosecond helical beams –or “structured attosecond light springs”– with rotating linear polarization along the azimuth. Our proposal overcomes the state of the art limitations for the generation of light beams far from the visible domain carrying non-integer orbital angular momentum and could be applied in fields such as diffraction imaging, EUV lithography, particle trapping, and super-resolution imaging. PMID:28281655

  9. Ultrasonic atomization of tissue and its role in tissue fractionation by high intensity focused ultrasound.

    PubMed

    Simon, Julianna C; Sapozhnikov, Oleg A; Khokhlova, Vera A; Wang, Yak-Nam; Crum, Lawrence A; Bailey, Michael R

    2012-12-07

    Atomization and fountain formation is a well-known phenomenon that occurs when a focused ultrasound wave in liquid encounters an air interface. High intensity focused ultrasound (HIFU) has been shown to fractionate a tissue into submicron-sized fragments in a process termed boiling histotripsy, wherein the focused ultrasound wave superheats the tissue at the focus, producing a millimetre-sized boiling or vapour bubble in several milliseconds. Yet the question of how this millimetre-sized boiling bubble creates submicron-sized tissue fragments remains. The hypothesis of this work is that the tissue can behave as a liquid such that it atomizes and forms a fountain within the vapour bubble produced in boiling histotripsy. We describe an experiment, in which a 2 MHz HIFU transducer (maximum in situ intensity of 24 000 W cm(-2)) was aligned with an air-tissue interface meant to simulate the boiling bubble. Atomization and fountain formation was observed with high-speed photography and resulted in tissue erosion. Histological examination of the atomized tissue showed whole and fragmented cells and nuclei. Air-liquid interfaces were also filmed. Our conclusion was that HIFU can fountain and atomize tissue. Although this process does not entirely mimic what was observed in liquids, it does explain many aspects of tissue fractionation in boiling histotripsy.

  10. Iron isotopic fractionation between silicate mantle and metallic core at high pressure.

    PubMed

    Liu, Jin; Dauphas, Nicolas; Roskosz, Mathieu; Hu, Michael Y; Yang, Hong; Bi, Wenli; Zhao, Jiyong; Alp, Esen E; Hu, Justin Y; Lin, Jung-Fu

    2017-02-20

    The +0.1‰ elevated (56)Fe/(54)Fe ratio of terrestrial basalts relative to chondrites was proposed to be a fingerprint of core-mantle segregation. However, the extent of iron isotopic fractionation between molten metal and silicate under high pressure-temperature conditions is poorly known. Here we show that iron forms chemical bonds of similar strengths in basaltic glasses and iron-rich alloys, even at high pressure. From the measured mean force constants of iron bonds, we calculate an equilibrium iron isotope fractionation between silicate and iron under core formation conditions in Earth of ∼0-0.02‰, which is small relative to the +0.1‰ shift of terrestrial basalts. This result is unaffected by small amounts of nickel and candidate core-forming light elements, as the isotopic shifts associated with such alloying are small. This study suggests that the variability in iron isotopic composition in planetary objects cannot be due to core formation.

  11. Fractional distillation

    SciTech Connect

    Brand, M. J.; Callejas, R. J.

    1985-10-08

    Process and apparatus are provided for the recovery of low, medium and high boiling components from feed streams containing same wherein reboiler fouling, gumming and the like are minimized, via the control of fractionator reboiler temperatures.

  12. Fractionalize this

    SciTech Connect

    Phillips, Philip

    2010-12-01

    Precisely what are the electrons in a high-temperature superconductor doing before they superconduct? Strong electronic correlations may give rise to composite rather than fractionalized excitations, as is typical in other strongly coupled systems such as quark matter.

  13. Highly Ionized Gas as a Diagnostic of the Inner NLR

    NASA Astrophysics Data System (ADS)

    Ward, M. J.; Mullaney, J.; Jin, C.; Davies, R.

    2010-05-01

    The spectra of AGN, from the ultraviolet to the near infrared, exhibit emission lines covering a wide range of ionization states, from neutral species such as [O i] λ 6300, up to [Fe iv] λ 5303. Here we report on some recent studies of the properties of highly ionized lines (HILs), plus two case studies of individual objects. Future IFU observations at high spatial and good spectral resolution will probe the excitation and kinematics of the gas in the zone between the extended NLR and unresolved BLR. Multi-component SED fitting can be used to link the source of photoionization with the strengths and ratios of the HILs.

  14. Method For Enhanced Gas Monitoring In High Density Flow Streams

    DOEpatents

    Von Drasek, William A.; Mulderink, Kenneth A.; Marin, Ovidiu

    2005-09-13

    A method for conducting laser absorption measurements in high temperature process streams having high levels of particulate matter is disclosed. An impinger is positioned substantially parallel to a laser beam propagation path and at upstream position relative to the laser beam. Beam shielding pipes shield the beam from the surrounding environment. Measurement is conducted only in the gap between the two shielding pipes where the beam propagates through the process gas. The impinger facilitates reduced particle presence in the measurement beam, resulting in improved SNR (signal-to-noise) and improved sensitivity and dynamic range of the measurement.

  15. Test Program for High Efficiency Gas Turbine Exhaust Diffuser

    SciTech Connect

    Norris, Thomas R.

    2009-12-31

    This research relates to improving the efficiency of flow in a turbine exhaust, and thus, that of the turbine and power plant. The Phase I SBIR project demonstrated the technical viability of “strutlets” to control stalls on a model diffuser strut. Strutlets are a novel flow-improving vane concept intended to improve the efficiency of flow in turbine exhausts. Strutlets can help reduce turbine back pressure, and incrementally improve turbine efficiency, increase power, and reduce greenhouse gas emmission. The long-term goal is a 0.5 percent improvement of each item, averaged over the US gas turbine fleet. The strutlets were tested in a physical scale model of a gas turbine exhaust diffuser. The test flow passage is a straight, annular diffuser with three sets of struts. At the end of Phase 1, the ability of strutlets to keep flow attached to struts was demonstrated, but the strutlet drag was too high for a net efficiency advantage. An independently sponsored followup project did develop a highly-modified low-drag strutlet. In combination with other flow improving vanes, complicance to the stated goals was demonstrated for for simple cycle power plants, and to most of the goals for combined cycle power plants using this particular exhaust geometry. Importantly, low frequency diffuser noise was reduced by 5 dB or more, compared to the baseline. Appolicability to other diffuser geometries is yet to be demonstrated.

  16. Guns and High Gas Output Devices Panel: Introduction

    NASA Technical Reports Server (NTRS)

    Simmons, Ronald L.; Kaste, Pamela J.

    2000-01-01

    A new panel known as the Guns and High Gas Output Panel was organized in 1999 under the auspices of the JANNAF Propellant and Characterization SubCommittee (PDCS). This is an introduction to our first meeting, purpose of the panel, and the scope of activities to be covered. The primary purpose of the panel is very simple: to provide a single focal point for interfacing Government Laboratories (Department of Defense and Department of Energy) and commercial industry researchers to share R&D activities and findings (i.e. facilitate the exchange of information) specifically aimed at gun-launched propulsion and high-gas output devices (gas generators and air bag inflators). Specific areas of interest included in the Panel's scope (and the Technical Data Base) are the following: (1) new propellant formulations and chemistry, (2) new ingredients, (3) ballistic effects of the new formulations and ingredients, (4) new processing methods unique to gun propellants, (5) thermochemistry of new ingredients, (6) unique physical and mechanical properties, (7) burning rates of new propellants and small scale closed bomb testing, (8) plasma effects on the propellant, and (9) unique safety and insensitive munitions properties.

  17. Guns and High Gas Output Devices Panel: Introduction

    NASA Technical Reports Server (NTRS)

    Simmons, Ronald L.; Kaste, Pamela J.

    2000-01-01

    A new panel known as the Guns and High Gas Output Panel was organized in 1999 under the auspices of the JANNAF Propellant and Characterization SubCommittee (PDCS). This is an introduction to our first meeting, purpose of the panel, and the scope of activities to be covered. The primary purpose of the panel is very simple: to provide a single focal point for interfacing Government Laboratories (Department of Defense and Department of Energy) and commercial industry researchers to share R&D activities and findings (i.e. facilitate the exchange of information) specifically aimed at gun-launched propulsion and high-gas output devices (gas generators and air bag inflators). Specific areas of interest included in the Panel's scope (and the Technical Data Base) are the following: (1) new propellant formulations and chemistry, (2) new ingredients, (3) ballistic effects of the new formulations and ingredients, (4) new processing methods unique to gun propellants, (5) thermochemistry of new ingredients, (6) unique physical and mechanical properties, (7) burning rates of new propellants and small scale closed bomb testing, (8) plasma effects on the propellant, and (9) unique safety and insensitive munitions properties.

  18. State of the art stationary and mobile infrastructure for the dynamic generation and dilution of traceable reference gas mixtures of Ammonia at ambient air amount fractions

    NASA Astrophysics Data System (ADS)

    Leuenberger, Daiana; Pascale, Céline; Guillevic, Myriam; Ackermann, Andreas; Niederhauser, Bernhard

    2017-04-01

    Ammonia (NH3) in the atmosphere is the major precursor for neutralising atmospheric acids and is thus affecting not only the long-range transport of sulphur dioxide and nitrogen oxides but also stabilises secondary particulate matter. These aerosols have negative impacts on air quality and human health. Moreover, they negatively affect terrestrial ecosystems after deposition. NH3 has been included in the air quality monitoring networks and emission reduction directives of European nations. Atmospheric concentrations are in the order of 0.5-500 nmol/mol. However, the lowest substance amount fraction of available certified reference material (CRM) is 10 μmol/mol. This due to the fact that adsorption on the walls of aluminium cylinders and desorption as pressure in the cylinder decreases cause substantial instabilities in the amount fractions of the gas mixtures. Moreover, analytical techniques to be calibrated are very diverse and cause challenges for the production and application of CRM. The Federal Institute of Metrology METAS has developed, partially in the framework of EMRP JRP ENV55 MetNH3, an infrastructure to meet with the different requirements in order to generate SI-traceable NH3 reference gas mixtures dynamically in the amount fraction range 0.5-500 nmol/mol and with uncertainties UNH3 <3%. The infrastructure consists of a stationary as well as a mobile device for full flexibility in the application: In the stationary system, a magnetic suspension balance monitors the specific temperature and pressure dependent mass loss over time of the pure substance in a permeation tube (here NH3) by permeation through a membrane into a constant flow of carrier gas. Subsequently, this mixture is diluted with a system of thermal mass flow controllers in one or two consecutive steps to desired amount fractions. The permeation tube with calibrated permeation rate (mass loss over time previously determined in the magnetic suspension balance) can be transferred into the

  19. Recognition and measurement gas-liquid two-phase flow in a vertical concentric annulus at high pressures

    NASA Astrophysics Data System (ADS)

    Li, Hao; Sun, Baojiang; Guo, Yanli; Gao, Yonghai; Zhao, Xinxin

    2017-08-01

    The air-water flow characteristics under pressure in the range of 1-6 MPa in a vertical annulus were evaluated in this report. Time-resolved bubble rising velocity and void fraction were also measured using an electrical void fraction meter. The results showed that the pressure has remarkable effect on the density, bubble size and rise velocity of the gas. Four flow patterns (bubble, cap-bubble, cap-slug, and churn) were also observed instead of Taylor bubble at high pressure. Additionally, the transition process from bubble to cap-bubble was investigated at atmospheric and high pressures, respectively. The results revealed that the flow regime transition criteria for atmospheric pressure do not work at high pressure, hence a new flow regime transition model for annular flow channel geometry was developed to predict the flow regime transition, which thereafter exhibited high accuracy at high pressure condition.

  20. Femtosecond laser excitation of mixed Ar/Kr clusters: peculiarities of K-line x-ray production from nanoplasma under varied fraction of initial gas components

    NASA Astrophysics Data System (ADS)

    Zhvaniya, I. A.; Dzhidzhoev, M. S.; Gordienko, V. M.

    2017-09-01

    For the first time, we defined the range of krypton fraction (C Kr) in an initial binary Ar-Kr gas mixture that provides the production of large (N ~ 106 atoms/cluster) mixed Ar/Kr clusters under co-expansion of the mixture at room temperature and the stagnant pressure of 25 bar. Mixed Ar/Kr clusters exist at the krypton fraction of 3-15%. The presence of mixed clusters is detected by the simultaneous generation of both x-ray Kα lines of argon (E  =  3.1 keV) and krypton (E  =  12.7 keV) from nanoplasma originating as a result of femtosecond nonlinear laser excitation with intensity about 5 · 1017 W cm-2. It was shown that the amplitude of lines in dual-energy x-ray spectrum can be controlled by proper selection of the fraction of initial gas mixture components. Maximal laser energy conversion efficiency to krypton x-ray line is achieved for pure krypton clusters (i.e. C Kr  =  100%) and reaches 2 · 10-7 at laser intensity of 5 · 1017 W cm-2. The laser energy conversion efficiency to argon x-ray line reaches the maximal value of 3 · 10-6 at C kr  =  0%.

  1. Safety aspects of modular high temperature gas cooled reactors

    SciTech Connect

    Kasten, P.R.

    1986-05-14

    Modular high temperature gas cooled reactors (MHTGRs) are being developed which have a high degree of passive safety. The advantageous safety characteristics are due to: the high heat capacity of the graphite core; the high temperature capability of the core components; the chemical stability and inertness of the fuel, coolant, and moderator; the high retention of fission products by the fuel coating; the single-phase characteristics of helium coolant; the inherent negative temperature coefficient of reactivity of the core; the defense in depth against air and water ingress events; and the ability to cool the reactor by passive heat transfer mechanisms following postulated accidents. Even for a number of accidents having very low probabilities of occurrence, the cumulative fission product release at the site boundary is estimated to be below those acceptable under the Protective Action Guidelines.

  2. High power gas laser - Applications and future developments

    NASA Technical Reports Server (NTRS)

    Hertzberg, A.

    1977-01-01

    Fast flow can be used to create the population inversion required for lasing action, or can be used to improve laser operation, for example by the removal of waste heat. It is pointed out that at the present time all lasers which are capable of continuous high-average power employ flow as an indispensable aspect of operation. High power laser systems are discussed, taking into account the gasdynamic laser, the HF supersonic diffusion laser, and electric discharge lasers. Aerodynamics and high power lasers are considered, giving attention to flow effects in high-power gas lasers, aerodynamic windows and beam manipulation, and the Venus machine. Applications of high-power laser technology reported are related to laser material working, the employment of the laser in controlled fusion machines, laser isotope separation and photochemistry, and laser power transmission.

  3. Electron beam treatment of exhaust gas with high NOx concentration

    NASA Astrophysics Data System (ADS)

    Licki, Janusz; Chmielewski, Andrzej G.; Pawelec, Andrzej; Zimek, Zbigniew; Witman, Sylwia

    2014-05-01

    Simulated exhaust gases with a high NOx concentration, ranging from 200 to 1700 ppmv, were irradiated by an electron beam from an accelerator. In the first part of this study, only exhaust gases were treated. Low NOx removal efficiencies were obtained for high NOx concentrations, even with high irradiation doses applied. In the second part of study, gaseous ammonia or/and vapor ethanol were added to the exhaust gas before its inlet to the plasma reactor. These additions significantly enhanced the NOx removal efficiency. The synergistic effect of high SO2 concentration on NOx removal was observed. The combination of electron beam treatment with the introduction of the above additions and with the performance of irradiation under optimal parameters ensured high NOx removal efficiency without the application of a solid-state catalyst.

  4. High power gas laser - Applications and future developments

    NASA Technical Reports Server (NTRS)

    Hertzberg, A.

    1977-01-01

    Fast flow can be used to create the population inversion required for lasing action, or can be used to improve laser operation, for example by the removal of waste heat. It is pointed out that at the present time all lasers which are capable of continuous high-average power employ flow as an indispensable aspect of operation. High power laser systems are discussed, taking into account the gasdynamic laser, the HF supersonic diffusion laser, and electric discharge lasers. Aerodynamics and high power lasers are considered, giving attention to flow effects in high-power gas lasers, aerodynamic windows and beam manipulation, and the Venus machine. Applications of high-power laser technology reported are related to laser material working, the employment of the laser in controlled fusion machines, laser isotope separation and photochemistry, and laser power transmission.

  5. Gas physics environment of high altitude Jovian entry.

    NASA Technical Reports Server (NTRS)

    Lefferdo, J. M.; Edquist, C. T.; Steel, P. C.

    1972-01-01

    A description of the gas physics environment associated with high-altitude Jupiter entry is reported. Two aspects of environmental analysis are treated. First, limited discussion is devoted to prediction of the heating environment of the probe aeroshell. Prime emphasis is given to the second aspect of the analysis, a description of the gas particle probe interaction phenomena in the rarefied flow regime. Several molecular reemission models have been devised and exercised. Model selection was based upon the desire to bracket the expected reemission characteristics. Consideration was given to examining diffuse reflection as exemplified by the Maxwellian model and lobular, specular reflection as characterized by the Nocilla model. Variation of fundamental input parameters was investigated to determine particle-probe interaction sensitivity. Regardless of neutral species type, results show that the attenuation of the incoming flux of that species by reflected particles is approximately 15 per cent in the stagnation region at 200 km above the cloud tops.

  6. Controls for offshore high pressure corrosive gas wells

    SciTech Connect

    Bailliet, R.M.

    1982-01-01

    In September 1981, Shell Oil Company began production from its first high-pressure corrosive gas well in the Gulf of Mexico. The extreme pressures and corrosive nature of the gas required the installation of a 20,000 psi low alloy steel christmas tree, equipped with 12 hydraulically operated safety and control valves. This study describes the instrumentation and control system developed to operate this complex well. Similar wells have been produced on shore, but the limited space available on an offshore platform has required the development of new techniques for operating these wells. The instrumentation system described utilizes conventional pneumatics and hydraulics for control plus intrinsically-safe electronics for data acquisition. The use of intrinsically-safe field wiring provided maximum safety while avoiding the need for explosion-proof conduit and wiring methods in division one hazardous areas.

  7. Vacuum surface flashover and high pressure gas streamers

    SciTech Connect

    Elizondo, J.M.; Krogh, M.L.; Smith, D.; Stolz, D.; Wright, S.N.; Sampayan, S.E.; Caporaso, G.J.; Vitello, P.; Tishchenko, N.

    1997-07-01

    Pre-breakdown current traces obtained during high pressure gas breakdown and vacuum surface flashover show similar signatures. The initial pre-breakdown current spike, a flat constant current phase, and the breakdown phase with voltage collapse and current surge differ mostly in magnitude. Given these similarities, a model, consisting of the initial current spike corresponding to a fast precursor streamer (ionization wave led by a photoionizing front), the flat current stage as the heating or glow phase, and the terminal avalanche and gap closure, is applied to vacuum surface flashover. A simple analytical approximation based on the resistivity changes induced in the vacuum and dielectric surface is presented. The approximation yields an excellent fit to pre-breakdown time delay vs applied field for previously published experimental data. A detailed kinetics model that includes surface and gas contributions is being developed based in the initial approximation.

  8. NOVEL GAS SENSORS FOR HIGH-TEMPERATURE FOSSIL FUEL APPLICATIONS

    SciTech Connect

    Palitha Jayaweera

    2004-05-01

    SRI is developing ceramic-based microsensors for detection of exhaust gases such as NO, NO{sub 2}, and CO in advanced combustion and gasification systems. The sensors detect the electrochemical activity of the exhaust gas species on catalytic electrodes and are designed to operate at high temperatures, elevated pressures, and corrosive environments typical of large power generation exhausts. Under this research project we are developing sensors for multiple gas detection in a single package along with data acquisition and control software and hardware. The sensor package can be easily integrated into online monitoring systems for active emission control. This report details the research activities performed from May 2004 to October 2004 including testing of catalytic materials, sensor design and fabrication, and software development.

  9. High-density equation of state for a lattice gas.

    PubMed

    Ushcats, M V

    2015-05-01

    For the lattice gas models of arbitrary geometry and dimensions with absolute repulsion between particles at zero distance (a hard core identical to a single lattice site) and arbitrary repulsion or attraction at other distances, the "hole-particle" symmetry of the system potential energy has been stated and an equation of state has been derived on the basis of the classical Gibbs statistics. The equation is completely analogous to the well-known virial equation of state, except that it is more accurate at high-density states, while the virial equation has the low-density limitation. Both equations contain the common set of the so-called irreducible integrals, related to the corresponding virial coefficients, and can be used together to describe the behavior of a lattice gas in a wide range of densities.

  10. Shallow Gas and Gas Hydrates in the Barents Sea Imaged by High-Resolution 3D Seismic Data

    NASA Astrophysics Data System (ADS)

    Planke, S.; Eriksen, O.; Eriksen, F. N.; Bunz, S.; Berndt, C.

    2012-12-01

    Shallow gas and gas hydrates are potential hazards for the petroleum industry, but may also represent future resources. Detailed mapping of shallow gas and gas hydrates is important to reduce drilling risks, to exploit hydrocarbon resources, and to better understand procesesse of gas migration and accumulation. We have collected two high resolution 3D seismic cubes of 10-20 km2 in areas with shallow gas in the Barents Sea. The cubes were acquired using the P-Cable system in water depths of 300-500 m with the vessel R/V Jan Mayen. The data were processed using the RadexPro software and a standard sequence including geometry, tide corrections, binning, filtering, and migration. Two main sedimentary sequences are present in the data, a sub-horizontal glacial package overlying a westward-dipping Paleogene sequence. The seabed is characterized by up to 15 m deep glacial ploughmarks. An upper regional unconformity (URU) separates the glacial and Paleogene sediments. Three levels of high-amplitude reflections are interpreted as evidence of shallow gas. Minor gas accumulations are present as semi-circular anomalies within the glacial sequence and as north-south trending anomalies just below the URU. More extensive gas accumulations are found within the Paleogene sediments, and the top gas reflections are clearly cross-cutting the dipping Paleogene sequence. Several paleo-pockmarks are interpreted within the glacial sequence, whereas no pockmarks are identified on the seafloor. The gas is interpreted to be sealed by overlying gas hydrates. Gas hydrate models show that pure methane is outside the gas hydrate stability field in the surveyed region, but within the gas hydrate stability field if methane is mixed with minor amounts of higher-order hydrocarbons (ethane and propane).

  11. Nanostructured Tungsten Oxide Composite for High-Performance Gas Sensors

    PubMed Central

    Feng-Chen, Siyuan; Aldalbahi, Ali; Feng, Peter Xianping

    2015-01-01

    We report the results of composite tungsten oxide nanowires-based gas sensors. The morphologic surface, crystallographic structures, and chemical compositions of the obtained nanowires have been investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman scattering, respectively. The experimental measurements reveal that each wire consists of crystalline nanoparticles with an average diameter of less than 250 nm. By using the synthesized nanowires, highly sensitive prototypic gas sensors have been designed and fabricated. The dependence of the sensitivity of tungsten oxide nanowires to the methane and hydrogen gases as a function of time has been obtained. Various sensing parameters such as sensitivity, response time, stability, and repeatability were investigated in order to reveal the sensing ability. PMID:26512670

  12. High-performance gas sensors with temperature measurement

    PubMed Central

    Zhang, Yong; Li, Shengtao; Zhang, Jingyuan; Pan, Zhigang; Min, Daomin; Li, Xin; Song, Xiaoping; Liu, Junhua

    2013-01-01

    There are a number of gas ionization sensors using carbon nanotubes as cathode or anode. Unfortunately, their applications are greatly limited by their multi-valued sensitivity, one output value corresponding to several measured concentration values. Here we describe a triple-electrode structure featuring two electric fields with opposite directions, which enable us to overcome the multi-valued sensitivity problem at 1 atm in a wide range of gas concentrations. We used a carbon nanotube array as the first electrode, and the two electric fields between the upper and the lower interelectrode gaps were designed to extract positive ions generated in the upper gap, hence significantly reduced positive ion bombardment on the nanotube electrode, which allowed us to maintain a high electric field near the nanotube tips, leading to a single-valued sensitivity and a long nanotube life. We have demonstrated detection of various gases and simultaneously monitoring temperature, and a potential for applications. PMID:23405281

  13. Vapor Pressure, Vapor Composition and Fractional Vaporization of High Temperature Lavas on Io

    NASA Technical Reports Server (NTRS)

    Fegley, B., Jr.; Schaefer, L.; Kargel, J. S.

    2003-01-01

    Observations show that Io's atmosphere is dominated by SO2 and other sulfur and sulfur oxide species, with minor amounts of Na, K, and Cl gases. Theoretical modeling and recent observations show that NaCl, which is produced volcanically, is a constituent of the atmosphere. Recent Galileo, HST and ground-based observations show that some volcanic hot spots on Io have extremely high temperatures, in the range 1400-1900 K. At similar temperatures in laboratory experiments, molten silicates and oxides have significant vapor pressures of Na, K, SiO, Fe, Mg, and other gases. Thus vaporization of these species from high temperature lavas on Io seems likely. We therefore modeled the vaporization of silicate and oxide lavas suggested for Io. Our results for vapor chemistry are reported here. The effects of fractional vaporization on lava chemistry are given in a companion abstract by Kargel et al.

  14. Upgrading of high-boiling fraction of bio-oil in supercritical methanol.

    PubMed

    Li, Wang; Pan, Chunyan; Sheng, Li; Liu, Zhen; Chen, Ping; Lou, Hui; Zheng, Xiaoming

    2011-10-01

    In this work, the upgrading reactions of high-boiling fraction (HBF) of bio-oil were carried out over a series of supported mono- and bi-metallic catalysts under the supercritical methanol condition. During these reactions, esterification and cracking (alcoholysis and hydrocracking) were the two dominant processes. PtNi/MgO exhibited good performance, and gave a high yield (72.4 wt.%) of refined oil. The acid-base properties of the supports have an important effect on the coke deposition on the catalyst surface. The acidic catalysts gave the somewhat lower product yields, but tended to inhibit coking reaction. This would improve the life of the catalysts in the practical applications. The refined oil is believed to be a potential substitute or partial substitute for the fossil transportation fuel.

  15. Quantifying Fractional Ground Cover on the Climate Sensitive High Plains Using AVIRIS and Landsat TM Data

    NASA Technical Reports Server (NTRS)

    Warner, Amanda Susan

    2002-01-01

    The High Plains is an economically important and climatologically sensitive region of the United States and Canada. The High Plains contain 100,000 sq km of Holocene sand dunes and sand sheets that are currently stabilized by natural vegetation. Droughts and the larger threat of global warming are climate phenomena that could cause depletion of natural vegetation and make this region susceptible to sand dune reactivation. This thesis is part of a larger study that is assessing the effect of climate variability on the natural vegetation that covers the High Plains using Landsat 5 and Landsat 7 data. The question this thesis addresses is how can fractional vegetation cover be mapped with the Landsat instruments using linear spectral mixture analysis and to what accuracy. The method discussed in this thesis made use of a high spatial and spectral resolution sensor called AVIRIS (Airborne Visible and Infrared Imaging Spectrometer) and field measurements to test vegetation mapping in three Landsat 7 sub-scenes. Near-simultaneous AVIRIS images near Ft. Morgan, Colorado and near Logan, New Mexico were acquired on July 10, 1999 and September 30, 1999, respectively. The AVIRIS flights preceded Landsat 7 overpasses by approximately one hour. These data provided the opportunity to test spectral mixture algorithms with AVIRIS and to use these data to constrain the multispectral mixed pixels of Landsat 7. The comparisons of mixture analysis between the two instruments showed that AVIRIS endmembers can be used to unmix Landsat 7 data with good estimates of soil cover, and reasonable estimates of non-photosynthetic vegetation and green vegetation. Landsat 7 derived image endmembers correlate with AVIRIS fractions, but the error is relatively large and does not give a precise estimate of cover.

  16. Simulated digestion and antioxidant activity of red wine fractions separated by high speed countercurrent chromatography.

    PubMed

    Noguer, Maria; Cerezo, Ana B; Rentzsch, Michael; Winterhalter, Peter; Troncoso, Ana M; García-Parrilla, Maria Carmen

    2008-10-08

    Wine is an important source of dietary antioxidants because of its phenolic compound content. The antioxidant activity (AA) of pure monomer substances present in wines, such as phenolic acids, flavanols, and anthocyanins, has already been described, but the AA of polymeric phenols is still unknown. In this study, we have fractionated a red wine by countercurrent chromatography (CCC) into four fractions: fraction 1, made up of polymeric compounds; fraction 2, containing malvidin-3-glucoside; fraction 3, containing peonidin-3-glucoside; and fraction 4, containing vitisin A. The AA of these fractions was determined by oxygen radical absorbance capacity and ferric reducing ability assays. The weight of fraction 1 was the largest, so this was the largest contributor to the AA of the wine. However, the antioxidant powers (muM Trolox/g fraction) of fractions 2-4 were similar and higher than that of fraction 1. We also determined AA before and after in vitro gastric and intestinal digestions. After gastric digestion, the AA was 100-1000 times higher than the original fraction values. Gallic acid was determined in gastric and intestinal digested fractions. After intestinal digestion, the concentrations of simple phenols, such as caffeic acid, p-coumaric acid, and protocatechualdehyde, increased as they were released from the fractions under our conditions. Protocatechuic acid was determined in more intestinal digested fractions than in gastric digested fractions. These results partly explain the increase in AA after the digestion and indicate the relevance of polymeric polyphenolic compounds as precursors of smaller molecules with biological activity.

  17. Brayton Cycle for High-Temperature Gas-Cooled Reactors

    SciTech Connect

    Oh, Chang H.; Moore, Richard L.

    2005-03-15

    This paper describes research on improving the Brayton cycle efficiency for a high-temperature gas-cooled reactor (HTGR). In this study, we are investigating the efficiency of an indirect helium Brayton cycle for the power conversion side of an HTGR power plant. A reference case based on a 250-MW(thermal) pebble bed HTGR was developed using helium gas as a working fluid in both the primary and power conversion sides. The commercial computer code HYSYS was used for process optimization. A numerical model using the Visual-Basic (V-B) computer language was also developed to assist in the evaluation of the Brayton cycle efficiency. Results from both the HYSYS simulation and the V-B model were compared with Japanese calculations based on the 300-MW(electric) Gas Turbine High-Temperature Reactor (GTHTR) that was developed by the Japan Atomic Energy Research Institute. After benchmarking our models, parametric investigations were performed to see the effect of important parameters on the cycle efficiency. We also investigated single-shaft versus multiple-shaft arrangements for the turbomachinery. The results from this study are applicable to other reactor concepts such as fast gas-cooled reactors, supercritical water reactors, and others.The ultimate goal of this study is to use other fluids such as supercritical carbon dioxide for the HTGR power conversion loop in order to improve the cycle efficiency over that of the helium Brayton cycle. This study is in progress, and the results will be published in a subsequent paper.

  18. Brayton Cycle for High Temperature Gas-Cooled Reactors

    SciTech Connect

    Chang Oh

    2005-03-01

    This paper describes research on improving the Brayton cycle efficiency for a high-temperature gas-cooled reactor (HTGR). In this study, we are investigating the efficiency of an indirect helium Brayton cycle for the power conversion side of an HTGR power plant. A reference case based on a 250-MW(thermal) pebble bed HTGR was developed using helium gas as a working fluid in both the primary and power conversion sides. The commercial computer code HYSYS was used for process optimization. A numerical model using the Visual-Basic (V-B) computer language was also developed to assist in the evaluation of the Brayton cycle efficiency. Results from both the HYSYS simulation and the V-B model were compared with Japanese calculations based on the 300-MW(electric) Gas Turbine High-Temperature Reactor (GTHTR) that was developed by the Japan Atomic Energy Research Institute. After benchmarking our models, parametric investigations were performed to see the effect of important parameters on the cycle efficiency. We also investigated single-shaft versus multiple-shaft arrangements for the turbomachinery. The results from this study are applicable to other reactor concepts such as fast gas-cooled reactors, supercritical water reactors, and others. The ultimate goal of this study is to use other fluids such as supercritical carbon dioxide for the HTGR power conversion loop in order to improve the cycle efficiency over that of the helium Brayton cycle. This study is in progress, and the results will be published in a subsequent paper.

  19. Disruption Mitigation With High-Pressure Noble Gas Injection

    NASA Astrophysics Data System (ADS)

    Whyte, D. G.

    2002-11-01

    As tokamak fusion research approaches the realization of burning plasmas, we must develop methods to control the damage caused by disruptions. In-vessel components are damaged in three principal ways: divertor surface melting/ablation by plasma heating, mechanical stresses caused by poloidal halo currents, and amplification of runaway relativistic electrons that eventually are lost into the wall. Experiments on the DIII-D tokamak have demonstrated a technique that mitigates the three disruption damage effects. A high-pressure jet of a noble gas (neon or argon) is injected into the plasma. The jet penetrates to the central plasma at the gas sound speed (300-500 m/s), seemingly due to the high ram pressure of the gas jet, and increases the atom/ion content in the plasma volume by a factor of 50 in several milliseconds. As a result, the plasma energy is dissipated uniformly by UV radiation over the entire wall, and the heat conducted to the divertor is reduced from 20%-40% of the initial plasma energy for an unmitigated disruption to <4%. The radiative collapse initiates a rapid current quench with the plasma remaining centered in the vessel, effectively reducing halo currents. Runaway electrons are controlled by the large density of bound electrons in the plasma volume, despite the large parallel electric field. Initial results on real-time disruption detection are encouraging, with the plasma control system triggering the neon gas jet injection into the unstable plasma and mitigating the disruption damage. Physical models developed to understand the DIII-D results describe the thermal/ionization balance and the evolution of halo currents well. Extrapolation to burning plasma experiments shows that thermal and halo current mitigation is possible and that runaway electrons can be suppressed.

  20. Why do the HIghMass Galaxies Have so Much Gas?: Studying Massive, Gas-Rich Galaxies at z~0 with Resolved HI and H2

    NASA Astrophysics Data System (ADS)

    Hallenbeck, Gregory L.; HIghMass Team

    2016-01-01

    In the standard ΛCDM cosmology, galaxies form via mergers of many smaller dark matter halos. Because mergers drive star formation, the most massive galaxies should also be the ones which have been the most efficient at converting their gas reservoirs into stars. This trend is seen observationally: in general, as stellar mass increases, gas fraction (GF = MHI/M*) decreases. Galaxies which have large reservoirs of atomic hydrogen (HI) are thus expected to be extremely rare, which was seemingly supported by earlier blind HI surveys.In seeming contradiction, ALFALFA, the Arecibo Legacy Fast ALFA Survey has observed a sample of 34 galaxies which are both massive (MHI>1010 M⊙) and have unusually high gas fractions (all ≥ 0.3; half are > 1). We call this sample HighMass. Unlike other extremely HI-massive samples, such galaxies are neither low surface brightness galaxies nor are they simply "scaled up" spirals. Could this gas be recently acquired, either from accreting small companions or directly from the cosmic web? Or is it primordial, and has been kept from forming stars, possibly because of an unusually high dark matter halo spin parameter?We present resolved HI, H2, and star formation properties of three of these HIghMass galaxies, and compare them with two HIghMass galaxies previously discussed in Hallenbeck et al. (2014). One of these galaxies, UGC 6168, appears in the process of transitioning from a quiescent to star-forming phase, as indicated by its bar and potential non-circular flows. A second, UGC 7899, has a clear warp, which could be evidence of recently accreted gas—but the presence of a warp is far from conclusive evidence. Both have moderately high dark matter halo spin parameters (λ' = 0.09), similar to the previously studied UGC 9037. The third, NGC 5230, looks undisturbed both optically and in its radio emission, but is in a group full of extragalactic gas. A neighboring galaxy has been significantly disrupted, and NGC 5230 may be in the

  1. Incorporation of Xe in silicates at high P and T: a mechanism for isotope fractionation and trapping at depth

    NASA Astrophysics Data System (ADS)

    Sanloup, C.; Schmidt, B. C.; Gudfinnsson, G. H.; Dewaele, A.; Mezouar, M.

    2011-12-01

    Xenon in the atmospheres of the Earth and Mars is characterized by a low abundance compared to other noble gases and by a depletion in light isotopes. By means of combined chemical analysis, in situ x-ray diffraction and Raman spectroscopy, we propose that Xe reacts with olivine at the high pressures and temperatures found in the upper mantle and in pre-terrestrial bodies. That provides a mechanism for the incorporation of Xe at depth and consequent isotopic fractionation. The substitution mechanism of Xe to Si depends on the type of silicate framework, forming XeO2 molecules in fully polymerized phases of silica, and XeO4 molecules in the isolated tetrahedra structure of olivine. Consequently, Xe retention in (Mg,Fe)2SiO4 olivine is less thermodynamically favored than in SiO2,implying lesser amounts of Xe trapped in olivine. This chemistry does not extend to the lighter noble gas Ar in the investigated pressure range. The incorporation of both Xe and Ar in olivine is correlated to its trace element content likely through the formation of vacancies, a pre-requisite for the retention of Xe on tetrahedral sites and Ar on octahedral sites.

  2. What is so super about super-emitters? Characterizing methane high emitters from natural gas infrastructure

    NASA Astrophysics Data System (ADS)

    Zavala Araiza, D.; Lyon, D. R.; Alvarez, R.; Harriss, R. C.; Palacios, V.; Hamburg, S.

    2015-12-01

    Methane emissions across the natural gas supply chain are dominated at any one time by a few high-emitters (super-emitters or fat-tail of the distribution), often underrepresented in published datasets used to construct emission inventories. Characterization of high-emitters is essential for improving emission estimates based on atmospheric data (top-down) and emission inventories (bottom-up). The population of high-emitters (e.g. 10-20% of sites that account for 80-90% of the emissions) is temporally and spatially dynamic. As a consequence, it is challenging to design sampling methods and construct estimates that accurately represent their frequency and magnitude of emissions. We present new methods to derive facility-specific emission distribution functions that explicitly integrate the influence of the relatively rare super-emitters. These methods were applied in the Barnett Shale region to construct a custom emission inventory that is then compared to top-down emission estimates for the region. We offer a methodological framework relevant to the design of future sampling campaigns, in which these high-emitters are seamlessly incorporated to representative emissions distributions. This framework can be applied to heterogeneous oil and gas production regions across geographies to obtain accurate regional emission estimates. Additionally, we characterize emissions relative to the fraction of a facility's total methane throughput; an effective metric to identify sites with excess emissions resulting from avoidable operating conditions, such as malfunctioning equipment (defined here as functional super-emitters). This work suggests that identifying functional super-emitters and correcting their avoidable operating conditions would result in significant emission reductions. However, due to their spatiotemporal dynamic behavior, achieving and maintaining uniformly low emissions across the entire population of sites will require mitigation steps (e.g. leak detection

  3. A high performance constant fraction discriminator for pulsed laser proximity fuze

    NASA Astrophysics Data System (ADS)

    Yao, Ping-ping; Tu, Bi-hai; Wang, Xiang-jing; Zhang, Yi; Zhao, Ping-jian

    2015-04-01

    A novel high performance timing discrimination circuit architecture for a pulsed laser proximity fuze based on constant fraction discrimination technique is constructed and tested. A LC resonant circuit is designed to replace the traditional transmission delay-line to accommodate the special requirements of laser proximity fuze for low size, power consumption, weight and cost. The walk error of the improved constant fraction discriminator is analyzed with lots of detailed experiments. The experiment results indicate that the discriminator eliminates the dependency of the echo pulse amplitude from the timing result, the walk error caused by the amplitude variation and the noise variation of the received echo pulse is less than 125ps, when the SNR is more than 20 and the echo pulse is 0.2V to 2.134V (20.12dB dynamic range). The error is less than 100ps when the SNR more than 60. Furthermore, Detection on the whole system integrating the timing discrimination circuit verifies that, the laser repetition frequency can reach 10 KHz, the accuracy of the system with a measurement time of 0.1ms is 1.45cm in the case of a noncooperative target at a measurement range from 2m to 24m at room temperature, which improve greatly the fixed distance precision of pulsed laser proximity fuze.

  4. Engraftment of DLA-nonidentical unrelated canine marrow after high-dose fractionated total body irradiation

    SciTech Connect

    Deeg, H.J.; Storb, R.; Shulman, H.M.; Weiden, P.L.; Graham, T.C.; Thomas, E.D.

    1982-04-01

    Marrow transplants were carried out between unrelated DLA-nonidentical dogs. Recipients were conditioned for transplantation by total body irradiation (TBI) given eigher as a single dose of 9 Gy (900 rad) or fractionated in three increments of 6 Gy (600 rad) each at intervals of 48 hr. All recipients received marrow, less than or equal to 4 x 10(8) cells/kg, and no buffy coat cells. No immunosuppression was given after grafting. All 10 dogs given single dose total body irradiation failed to show engraftment and died with marrow aplasia and infectious complications (median survival 12 days). In contrast, all 10 dogs given fractionated TBI had sustained engraftment and died with graft-versus-host disease (GVHD) and infectious complications (median survival 12.5 days). None of the dogs died from radiation-induced gastroenteritis. In conclusion, resistance to DLA-nonidentical unrelated marrow grafts can be abrogated by high-dose TBI. This technique may allow hemopoietic engraftment even after i vitro manipulation of the marrow such as lymphocyte depletion by cell separation or treatment with anti-T cell antisera.

  5. Engraftment of DLA-nonidentical unrelated canine marrow after high-dose fractionated total body irradiation

    SciTech Connect

    Deeg, H.J.; Storb, R.; Shulman, H.M.; Weiden, P.L.; Graham, T.C.; Thomas, E.D.

    1982-04-01

    Marrow transplants were carried out between unrelated DLA-nonidentical dogs. Recipients were conditioned for transplantation by total body irradiation (TBI) given either as a single dose of 9 Gy (900 rad) or fractionated in three increments of 6 Gy (600 rad) each at intervals of 48 hr. All recipients received marrow, less than or equal to to 4 X 10/sup 8/ cells/kg, and no buffy coat cells. No immunosuppression was given after grafting. All 10 dogs given single-dose total body irradiation failed to show engraftment and died with marrow aplasia and infectious complications (median survival 12 days). In contrast, all 10 dogs given fractionated TBI had sustained engraftment and died with graft-versus-host disease (GVHD) and infectious complications (median survival 12.5 days). None of the dogs died from radiation-induced gastroenteritis.In conclusion, resistance to DLA-nonidentical unrelated marrow grafts can be abrogated by high-dose TBI. This technique may allow hemopoietic engraftment even after in vitro manipulation of the marrow such as lymphocyte depletion by cell separation or treatment with anti-T cell antisera.

  6. Evaluation of current drive requirements and operating characteristics of a high bootstrap fraction advanced tokamak reactor

    NASA Astrophysics Data System (ADS)

    Houlberg, W. A.; Attenberger, S. E.

    The reactor potential of some advanced physics operating modes proposed for the TPX physics program are examined. A moderate aspect ratio (A = 4.5 as in TPX), 2 GW reactor is analyzed because of its potential for steady-state, noninductive operation with high bootstrap current fraction. Particle, energy, and toroidal current equations are evolved to steady-state conditions using the 1 1/2-D time-dependent WHIST transport code. The solutions are therefore consistent with particle, energy, and current sources and assumed transport models. Fast wave current drive (FWCD) provides the axial seed current. The bootstrap current typically provides 80-90% of the current, while feedback on the lower hybrid current drive (LHCD) power maintains the total current. The sensitivity of the plasma power amplification factor, Q equivalent to P(sub fus)/P(sub aux), to variations in the plasma properties is examined. The auxiliary current drive power, P(sub aux) = P(sub LH) + P(sub FW); bootstrap current fraction; current drive efficiency; and other parameters are evaluated. The plasma is thermodynamically stable for the energy confinement model assumed (a multiple of ITER89P). The FWCD and LHCD sources provide attractive control possibilities, not only for the current profile, but also for the total fusion power since the gain on the incremental auxiliary power is typically 10-30 in these calculations when overall Q approximately equals 30.

  7. Evaluation of current drive requirements and operating characteristics of a high bootstrap fraction advanced tokamak reactor

    SciTech Connect

    Houlberg, W.A.; Attenberger, S.E.

    1994-11-01

    The reactor potential of some advanced physics operating modes proposed for the TPX physics program are examined. A moderate aspect ratio (A = 4.5 as in TPX), 2 GW reactor is analyzed because of its potential for steady-state, non-inductive operation with high bootstrap current fraction. Particle, energy and toroidal current equations are evolved to steady-state conditions using the 1-1/2-D time-dependent WHIST transport code. The solutions are therefore consistent with particle, energy and current sources and assumed transport models. Fast wave current drive (FWCD) provides the axial seed current. The bootstrap current typically provides 80-90% of the current, while feedback on the lower hybrid current drive (LHCD) power maintains the total current. The sensitivity of the plasma power amplification factor, Q {triple_bond} P{sub fus}/P{sub aux}, to variations in the plasma properties is examined. The auxiliary current drive power, P{sub aux} = P{sub LH} + P{sub FW}; bootstrap current fraction; current drive efficiency; and other parameters are evaluated. The plasma is thermodynamically stable for the energy confinement model assumed (a multiple of ITER89P). The FWCD and LHCD sources provide attractive control possibilities, not only for the current profile, but also for the total fusion power since the gain on the incremental auxiliary power is typically 10-30 in these calculations when overall Q {approx} 30.

  8. Evaluation of current drive requirements and operating characteristics of a high bootstrap fraction advanced tokamak reactor

    SciTech Connect

    Houlberg, W.A.; Attenberger, S.E.

    1995-02-01

    The reactor potential of some advanced physics operating modes proposed for the TPX physics program are examined. A moderate aspect ratio (A = 4.5 as in TPX), 2 GW reactor is analyzed because of its potential for steady-state, non-inductive operation with high bootstrap current fraction. Particle, energy and toroidal current equations are evolved to steady-state conditions using the 1-1/2-D time-dependent WHIST transport code. The solutions are therefore consistent with particle, energy and current sources and assumed transport models. Fast wave current drive (FWCD) provides the axial seed current. The bootstrap current typically provides 80-90% of the current, while feedback on the lower hybrid current drive (LHCD) power maintains the total current. The sensitivity of the plasma power amplification factor, Q {equivalent_to} P{sub fus}/P{sub aux}, to variations in the plasma properties is examined. The auxiliary current drive power, P{sub aux} = P{sub LH} + P{sub FW}; bootstrap current fraction: current drive efficiency; and other parameters are evaluated. The plasma is thermodynamically stable for the energy confinement model assumed (a multiple of ITER89P). The FWCD and LHCD sources provide attractive control possibilities, not only for the current profile, but also for the total fusion power since the gain on the incremental auxiliary power is typically 10-30 in these calculations when overall Q {approx} 30.

  9. Esophageal Toxicity From High-Dose, Single-Fraction Paraspinal Stereotactic Radiosurgery

    SciTech Connect

    Cox, Brett W.; Jackson, Andrew; Hunt, Margie; Bilsky, Mark; Yamada, Yoshiya

    2012-08-01

    Purpose: To report the esophageal toxicity from single-fraction paraspinal stereotactic radiosurgery (SRS) and identify dosimetric and clinical risk factors for toxicity. Methods and Materials: A total of 204 spinal metastases abutting the esophagus (182 patients) were treated with high-dose single-fraction SRS during 2003-2010. Toxicity was scored using the National Cancer Institute Common Toxicity Criteria for Adverse Events, version 4.0. Dose-volume histograms were combined to generate a comprehensive atlas of complication incidence that identifies risk factors for toxicity. Correlation of dose-volume factors with esophageal toxicity was assessed using Fisher's exact test and logistic regression. Clinical factors were correlated with toxicity. Results: The median dose to the planning treatment volume was 24 Gy. Median follow-up was 12 months (range, 3-81). There were 31 (15%) acute and 24 (12%) late esophageal toxicities. The rate of grade {>=}3 acute or late toxicity was 6.8% (14 patients). Fisher's exact test resulted in significant median splits for grade {>=}3 toxicity at V12 = 3.78 cm{sup 3} (relative risk [RR] 3.7, P=.05), V15 = 1.87 cm{sup 3} (RR 13, P=.0013), V20 = 0.11 cm{sup 3} (RR 6, P=0.01), and V22 = 0.0 cm{sup 3} (RR 13, P=.0013). The median split for D2.5 cm{sup 3} (14.02 Gy) was also a significant predictor of toxicity (RR 6; P=.01). A highly significant logistic regression model was generated on the basis of D2.5 cm{sup 3}. One hundred percent (n = 7) of grade {>=}4 toxicities were associated with radiation recall reactions after doxorubicin or gemcitabine chemotherapy or iatrogenic manipulation of the irradiated esophagus. Conclusions: High-dose, single-fraction paraspinal SRS has a low rate of grade {>=}3 esophageal toxicity. Severe esophageal toxicity is minimized with careful attention to esophageal doses during treatment planning. Iatrogenic manipulation of the irradiated esophagus and systemic agents classically associated with radiation

  10. Five-Year Outcomes of High-Dose Single-Fraction Spinal Stereotactic Radiosurgery

    SciTech Connect

    Moussazadeh, Nelson; Lis, Eric; Katsoulakis, Evangelia; Kahn, Sweena; Svoboda, Marek; DiStefano, Natalie M.; McLaughlin, Lily; Bilsky, Mark H.; Yamada, Yoshiya; Laufer, Ilya

    2015-10-01

    Purpose: To characterize local tumor control and toxicity risk in very long-term survivors (>5 years) after high-dose spinal image guided, intensity modulated radiation therapy delivered as single-dose stereotactic radiosurgery (SRS). Previously published spinal SRS outcome analyses have included a heterogeneous population of cancer patients, mostly with short survival. This is the first study reporting the long-term tumor control and toxicity profiles after high-dose single-fraction spinal SRS. Methods and Materials: The study population included all patients treated from June 2004 to July 2009 with single-fraction spinal SRS (dose 24 Gy) who had survived at least 5 years after treatment. The endpoints examined included disease progression, surgical or radiation retreatment, in-field fracture development, and radiation-associated toxicity, scored using the Radiation Therapy Oncology Group radiation morbidity scoring criteria and the Common Terminology Criteria for Adverse Events, version 4.0. Local control and fracture development were assessed using Kaplan-Meier analysis. Results: Of 278 patients, 31 (11.1%), with 36 segments treated for spinal tumors, survived at least 5 years after treatment and were followed up radiographically and clinically for a median of 6.1 years (maximum 102 months). The histopathologic findings for the 5-year survivors included radiation-resistant metastases in 58%, radiation-sensitive metastases in 22%, and primary bone tumors in 19%. In this selected cohort, 3 treatment failures occurred at a median of 48.6 months, including 2 recurrences in the radiation field and 1 patient with demonstrated progression at the treatment margins. Ten lesions (27.8%) were associated with acute grade 1 cutaneous or gastrointestinal toxicity. Delayed toxicity ≥3 months after treatment included 8 cases (22.2%) of mild neuropathy, 2 (5.6%) of gastrointestinal discomfort, 8 (22.2%) of dermatitides, and 3 (8.3%) of myalgias/myositis. Thirteen

  11. High octane ethers from synthesis gas-derived alcohols

    SciTech Connect

    Klier, K.; Herman, R.G.; Feeley, O.C.; Johansson, M.A.

    1992-07-01

    The objective of the proposed research is to synthesize high octane ethers, primarily methyl isobutyl ether (MIBE) and methyl tertiary butyl ether (MTBE), directly from H[sub 2]/CO/CO[sub 2] coal-derived synthesis gas via alcohol mixtures that are rich in methanol and 2-methyl-l-propanol (isobutanol). The overall scheme involves gasification of coal, purification and shifting of the synthesis gas, higher alcohol synthesis, and direct synthesis of ethers. The last stage of the synthesis involves direct coupling of synthesis gas-derived methanol and isobutanol that has been demonstrated by us to occur over superacid catalysts to yield methyl isobutyl ether (MIBE) at moderate pressures and a mixture of methanol and isobutene at low pressures. MIBE is an isomer of MTBE and a process is proposed whereby MTBE from the two alcohols is maximized and MIBE is minimized. This will be achieved by the proper choice of reaction conditions, i.e. intermediate pressures, and of inorganic acid catalysts that are stable at temperatures higher than 200[degree]C, at which the carbonium ion reaction coupling of the two alcohols to MTBE is more effective than the oxonium ion or ester reaction coupling to MIBE. Both organic and inorganic catalysts will be investigated, and the better catalysts of these classes will be subjected to long term performance studies. The long term performance studies of the combined process will extend to 1000 hr and detailed analytical data for all products will be provided.

  12. Gas

    MedlinePlus

    ... 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 you swallow less air ...

  13. Instability Analysis of a Low-Density Gas Jet Injected into a High-Density Gas

    NASA Technical Reports Server (NTRS)

    Lawson, Anthony Layiwola

    2001-01-01

    The objective of this study was to determine the effects of buoyancy on the absolute instability of low-density gas jets injected into high-density gas mediums. Most of the existing analyses of low-density gas jets injected into a high-density ambient have been carried out neglecting effects of gravity. In order to investigate the influence of gravity on the near-injector development of the flow, a linear temporal stability analysis and a spatio-temporal stability analysis of a low-density round jet injected into a high-density ambient gas were performed. The flow was assumed to be isothermal and locally parallel; viscous and diffusive effects were ignored. The variables were represented as the sum of the mean value and a normal-mode small disturbance. An ordinary differential equation governing the amplitude of the pressure disturbance was derived. The velocity and density profiles in the shear layer, and the Froude number (signifying the effects of gravity) were the three important parameters in this equation. Together with the boundary conditions, an eigenvalue problem was formulated. Assuming that the velocity and density profiles in the shear layer to be represented by hyperbolic tangent functions, the eigenvalue problem was solved for various values of Froude number. The temporal growth rates and the phase velocity of the disturbances were obtained. It was found that the presence of variable density within the shear layer resulted in an increase in the temporal amplification rate of the disturbances and an increase in the range of unstable frequencies, accompanied by a reduction in the phase velocities of the disturbances. Also, the temporal growth rates of the disturbances were increased as the Froude number was reduced (i.e. gravitational effects increased), indicating the destabilizing role played by gravity. The spatio-temporal stability analysis was performed to determine the nature of the absolute instability of the jet. The roles of the density ratio

  14. Online Measurements of Highly Oxidized Organics in the Gas and Particle phase during SOAS and SENEX

    NASA Astrophysics Data System (ADS)

    Lopez-Hilfiker, F.; Lee, B. H.; Mohr, C.; Ehn, M.; Rubach, F.; Mentel, T. F.; Kleist, E.; Thornton, J. A.

    2014-12-01

    We present measurements of a large suite of gas and particle phase organic compounds made with a Filter Inlet for Gas and AEROsol (FIGAERO) coupled to a high resolution time of flight chemical ionization mass spectrometer (HR-ToF-CIMS) developed at the University of Washington and with airborne HR-ToF-CIMS measurements. The FIGAERO instrument was deployed on the Jülich Plant Atmosphere Chamber to study α-pinene oxidation, and subsequently at the SMEAR II forest station in Hyytiälä, Finland and the SOAS ground site, in Brent Alabama. During the Southern Atmosphere Study, a gas-phase only version of the HR-ToF-CIMS was deployed on the NOAA WP-3 aircraft as part of SENEX. We focus here on highly oxygenated organic compounds derived from monoterpene oxidation detected both aloft during SENEX and at the ground-based site during SOAS. In both chamber and the atmosphere, many highly oxidized, low volatility compounds were observed in the gas and particles and many of the same compositions detected in the gas-phase were detected in the particles upon temperature programmed thermal desorption. The fraction of a given compound measured in the particle phase follows expected trends with elemental composition such as O/C ratios, but many compounds would not be well described by an absorptive partitioning model assuming unity activity coefficients. The detailed structure in the thermograms reveals a significant contribution from large molecular weight organics and/or oligomers in both chamber and ambient aerosol samples. Approximately 50% of the measured organics in the particle phase are associated with compounds having effective vapour pressures 4 or more orders of magnitude lower than commonly measured monoterpene oxidation products. We discuss the implications of these findings for measurements of gas-particle partitioning and for evaluating the contribution of monoterpene oxidation to organic aerosol formation and growth. We also use the aircraft measurements and a

  15. Gas transfer under high wind and its dependence on wave breaking and sea state

    NASA Astrophysics Data System (ADS)

    Brumer, Sophia; Zappa, Christopher; Fairall, Christopher; Blomquist, Byron; Brooks, Ian; Yang, Mingxi

    2016-04-01

    Quantifying greenhouse gas fluxes on regional and global scales relies on parameterizations of the gas transfer velocity K. To first order, K is dictated by wind speed (U) and is typically parameterized as a non-linear functions of U. There is however a large spread in K predicted by the traditional parameterizations at high wind speed. This is because a large variety of environmental forcing and processes (Wind, Currents, Rain, Waves, Breaking, Surfactants, Fetch) actually influence K and wind speed alone cannot capture the variability of air-water gas exchange. At high wind speed especially, breaking waves become a key factor to take into account when estimating gas fluxes. The High Wind Gas exchange Study (HiWinGS) presents the unique opportunity to gain new insights on this poorly understood aspects of air-sea interaction under high winds. The HiWinGS cruise took place in the North Atlantic during October and November 2013. Wind speeds exceeded 15 m s-1 25% of the time, including 48 hrs with U10 > 20 m s-1. Continuous measurements of turbulent fluxes of heat, momentum, and gas (CO2, DMS, acetone and methanol) were taken from the bow of the R/V Knorr. The wave field was sampled by a wave rider buoy and breaking events were tracked in visible imagery was acquired from the port and starboard side of the flying bridge during daylight hours at 20Hz. Taking advantage of the range of physical forcing and wave conditions sampled during HiWinGS, we test existing parameterizations and explore ways of better constraining K based on whitecap coverage, sea state and breaking statistics contrasting pure windseas to swell dominated periods. We distinguish between windseas and swell based on a separation algorithm applied to directional wave spectra for mixed seas, system alignment is considered when interpreting results. The four gases sampled during HiWinGS ranged from being mostly waterside controlled to almost entirely airside controlled. While bubble-mediated transfer

  16. THE MOLECULAR GAS CONTENT OF z = 3 LYMAN BREAK GALAXIES: EVIDENCE OF A NON-EVOLVING GAS FRACTION IN MAIN-SEQUENCE GALAXIES AT z > 2

    SciTech Connect

    Magdis, Georgios E.; Rigopoulou, D.; Daddi, E.; Sargent, M.; Elbaz, D.; Gobat, R.; Tan, Q.; Aussel, H.; Feruglio, C.; Charmandaris, V.; Dickinson, M.; Reddy, N.

    2012-10-10

    We present observations of the CO[J = 3 {yields} 2] emission toward two massive and infrared luminous Lyman break galaxies (LBGs) at z = 3.21 and z = 2.92, using the IRAM Plateau de Bure Interferometer, placing first constraints on the molecular gas masses (M{sub gas}) of non-lensed LBGs. Their overall properties are consistent with those of typical (main-sequence) galaxies at their redshifts, with specific star formation rates {approx}1.6 and {approx}2.2 Gyr{sup -1}, despite their large infrared luminosities (L{sub IR} Almost-Equal-To (2-3) Multiplication-Sign 10{sup 12} L{sub Sun }) derived from Herschel. With one plausible CO detection (spurious detection probability of 10{sup -3}) and one upper limit, we investigate the evolution of the molecular gas-to-stellar mass ratio (M{sub gas}/M{sub *}) with redshift. Our data suggest that the steep evolution of M{sub gas}/M{sub *} of normal galaxies up to z {approx} 2 is followed by a flattening at higher redshifts, providing supporting evidence for the existence of a plateau in the evolution of the specific star formation rate at z > 2.5.

  17. Fractional factorial study of HCN removal over a 0.5% Pt/Al₂O₃ catalyst: effects of temperature, gas flow rate, and reactant partial pressure

    SciTech Connect

    Zhao, Haibo; Tonkyn, Russell G.; Barlow, Stephan E.; Peden, Charles HF.; Koel, Bruce E.

    2006-01-07

    Fractional factorial design was used to determine which factors have significant effects on the HCN (hydrogen cyanide) oxidation reaction over 0.5% Pt/Al?O? under lean conditions. We conclude that the reaction temperature and gas-hourly space velocity (GHSV) have significant effects on the HCN conversion, while no significant effects are caused by the presence of either NO (nitric oxide) or C?H? (propene). A central composite design was used to study the effects of temperature and GHSV on HCN conversion, C?H? conversion and NOx selectivity. Based on a second polynomial equation model, regression analysis was used to study the significance of each variable term and derive equations for each response. Our results show that HCN conversion was significantly affected by temperature (X3), GHSV (X4), a temperature polynomial term (X32), and a temperature and GHSV interaction term (X3X4). HCN conversion decreased with increasing values of GHSV and increased with increasing temperature, up to a transition temperature that depends on the GHSV value. The variables of temperature (X3), GHSV (X4), and the temperature polynomial term (X32) have significant effects on both C?H? conversion and NOx selectivity, but in these two cases the interaction of temperature and GHSV was not significant. Contour plots of HCN conversion, C?H? conversion, and NOx selectivity versus temperature and GHSV were constructed from an analysis of the measured data, and these plots can be utilized to estimate HCN conversion, C?H? conversion, and NOx selectivity over the range of temperatures and GHSV investigated. Optimum catalyst operation is described by high HCN conversion and low NOx selectivity. These results show C and o that the highest HCN conversion was achieved at temperatures above 250 relatively low GHSV values, while low NOx selectivity was best achieved at a C.o temperature of 215

  18. Mass-independent fractionation of oxygen isotopes during H2O2 formation by gas-phase discharge from water vapour

    NASA Astrophysics Data System (ADS)

    Velivetskaya, Tatiana A.; Ignatiev, Alexander V.; Budnitskiy, Sergey Y.; Yakovenko, Victoria V.; Vysotskiy, Sergey V.

    2016-11-01

    Hydrogen peroxide is an important atmospheric component involved in various gas-phase and aqueous-phase transformation processes in the Earth's atmosphere. A study of mass-independent 17O anomalies in H2O2 can provide additional insights into the chemistry of the modern atmosphere and, possibly, of the ancient atmosphere. Here, we report the results of laboratory experiments to study the fractionation of three oxygen isotopes (16O, 17O, and 18O) during H2O2 formation from products of water vapour dissociation. The experiments were carried out by passing an electrical discharge through a gaseous mixture of helium and water at atmospheric pressure. The effect of the presence of O2 in the gas mixture on the isotopic composition of H2O2 was also investigated. All of the experiments showed that H2O2 produced under two different conditions (with or without O2 added in the gas mixtures) was mass-independently fractionated (MIF). We found a positive MIF signal (∼1.4‰) in the no-O2 added experiments, and this signal increased to ∼2.5‰ once O2 was added (1.6% mixing ratio). We suggest that if O2 concentrations are very low, the hydroxyl radical recombination reaction is the dominant pathway for H2O2 formation and is the source of MIF in H2O2. Although H2O2 formation via a hydroxyl radical recombination process is limited in the modern atmosphere, it would be possible in the Archean atmosphere when O2 was a trace constituent, and H2O2 would be mass-independently fractionated. The anomalous 17O excess, which was observed in H2O2 produced by spark discharge experiments, may provide useful information about the radical chemistry of the ancient atmosphere and the role of H2O2 in maintaining and controlling the atmospheric composition.

  19. Particle velocity and solid volume fraction measurements with a new capacitive flowmeter at the Solid/Gas Flow Test Facility. [Glass beads

    SciTech Connect

    Bobis, J.P.; Porges, K.G.A.; Raptis, A.C.; Brewer, W.E.; Bernovich, L.T.

    1986-08-01

    The performance of a new capacitive flowmeter has been assessed experimentally in a gas-entrained solid flow stream at the Argonne National Laboratory (ANL) Solid/Gas Flow Test Facility (S/GFTF) for solid feedrates in the range of 0.5 to 2 kg/s and solid-gas loadings up to 22, corresponding to a range of solid volume fractions extending from 0.004 to 0.016. Two types of nonintrusive instruments using the capacitive principle were fabricated at ANL and installed in the horizontal leg of a 12.3 m test section to sense the solids. An improved electrode geometry designed to maximize the coverage of the duct interior while minimizing the readout error due to a nonuniform electric field, was incorporated for one spoolpiece with the sensing electrodes on the outside surface of a ceramic liner and for another spoolpiece with the sensing electrodes mounted flush with the duct inside surface. The capacitive instruments measured the solid volume fraction and the average particle velocity. The results are compared with time-of-flight measurements of short-lived radioactive particles that duplicate closely the size and density of the 1000..mu.. glass beads used in these flow tests. Results show that the solid volume fraction measurements agree with the theoretical models presented and that the particle velocity deduced from the cross-correlation scheme agreed to within 5% of the irradiated particle velocity technique for the 21 to 31 m/s range generated with the S/GFTF. 43 refs., 36 figs., 19 tabs.

  20. Vortices in a highly rotating Bose condensed gas

    NASA Astrophysics Data System (ADS)

    Coddington, I. R.

    Superfluids, with their dissipationless flow and exotic topologies, have puzzled researchers in diverse fields of physics for almost a century. One of the hallmark features of superfluids is their response to rotation, which requires the fluid to be pierced by an array quantized singularities or vortices. Over the past few years, vortices and the lattices they organize into have become one of the major fields of experimental research with dilute gas Bose-Einstein condensates. This thesis explores the physics of vortices and vortex lattices in the dilute gas Bose-Einstein condensate while drawing connections to other superfluid systems. In addition to characterizing several equilibrium vortex effects, this work also studies several excitations. By removing atoms from the rotating condensate with a tightly focused, resonant laser, the density can be locally suppressed, creating aggregate vortices containing many units of circulation. These so called "giant vortices" offer insight into the dynamical stability of density defects in this system. Using similar techniques we can excite and directly image Tkachenko waves in the vortex. These low frequency modes are a consequence of the small but nonvanishing elastic shear modulus of the vortex-filled superfluid. Finally, by working at extremely high rotations we can create a Bose-Einstein condensates in the lowest Landau level. In this regime, which requires rotation rates greater than 99% of the centrifugal limit for a harmonically trapped gas, we are able to observe several expected and unexpected shifts in the physical properties of the condensate. In conclusion the dilute gas Bose-Einstein condensates offers a rich system in which to study vortex physics, and explore dynamical effects common to all rotating superfluids.

  1. High-Velocity H I Gas in Supernova Remnants

    NASA Astrophysics Data System (ADS)

    Koo, Bon-Chul

    1993-05-01

    Using the Hat Creek 85 foot telescope, we had carried out a survey of H I 21 cm emission lines toward all 103 known northern supernova remnants (SNRs) in order to find rapidly expanding SNR shells (Koo & Heiles 1991). We detected 15 SNRs that have associated high-velocity (HV) H I gas, most of which are quite likely the gas accelerated by the SN blast wave. Although the large beam-size (FWHM~ 30') of the 85 foot telescope prevented us to see the structure of the HV H I gas, the H I mass distribution in line-of-sight velocity suggested clumpy shell structures in several SNRs. In order to resolve the structure of the HV H I gas, we have been carrying out high-resolution H I 21 cm line observations using the Arecibo telescope and the VLA. We report preliminary results on two SNRs, CTB 80 and W51. In CTB 80, the VLA observations revealed fast moving H I clumps, which have a dense (n_H ~ 100 cm(-3) ) core surrounded by a relatively diffuse envelope. The clumps are small, 3 pc to 5 pc, and have velocities between +40 km s(-1) and +80 km s(-1) with respect to the systematic velocity of CTB 80. The clumps have relatively large momentum per unit volume, which implies that they have been swept-up at an early stage of the SNR evolution. By analyzing the Arecibo data, we found that the interstellar medium around CTB 80 is far from being uniform and homogeneous, which explains the peculiar morphology of CTB 80 in infrared and radio continuum. In W51, HV H I gas moving up to v_LSR>+150 km s(-1) has been detected. The H I distribution is elongated along the northwest-southeast direction, and the peak is very close to an X-ray bright region. We discuss the implications of our results in relation to the X-ray and the radio continuum morphology of W51. This work was supported in part by NON DIRECTED RESEARCH FUND, Korea Research Foundation, 1992.

  2. Modeling high-pressure adsorption of gas mixtures on activated carbon and coal using a simplified local-density model.

    PubMed

    Fitzgerald, James E; Robinson, Robert L; Gasem, Khaled A M

    2006-11-07

    The simplified local-density (SLD) theory was investigated regarding its ability to provide accurate representations and predictions of high-pressure supercritical adsorption isotherms encountered in coalbed methane (CBM) recovery and CO2 sequestration. Attention was focused on the ability of the SLD theory to predict mixed-gas adsorption solely on the basis of information from pure gas isotherms using a modified Peng-Robinson (PR) equation of state (EOS). An extensive set of high-pressure adsorption measurements was used in this evaluation. These measurements included pure and binary mixture adsorption measurements for several gas compositions up to 14 MPa for Calgon F-400 activated carbon and three water-moistened coals. Also included were ternary measurements for the activated carbon and one coal. For the adsorption of methane, nitrogen, and CO2 on dry activated carbon, the SLD-PR can predict the component mixture adsorption within about 2.2 times the experimental uncertainty on average solely on the basis of pure-component adsorption isotherms. For the adsorption of methane, nitrogen, and CO2 on two of the three wet coals, the SLD-PR model can predict the component adsorption within the experimental uncertainties on average for all feed fractions (nominally molar compositions of 20/80, 40/60, 60/40, and 80/20) of the three binary gas mixture combinations, although predictions for some specific feed fractions are outside of their experimental uncertainties.

  3. Fingerprinting of the volatile fraction from selected thyme species by means of headspace gas chromatography with mass spectrometric detection.

    PubMed

    Staszek, Dorota; Orłowska, Marta; Rzepa, Józef; Wróbel, Michał S; Kowalska, Teresa; Szymczak, Grażyna; Waksmundzka-Hajnos, Monika

    2014-01-01

    The Thymus genus has a firm position in Mediterranean folk medicine and culinary tradition, and yet certain confusion is observed in its botanical taxonomy. Therefore, chemical analysis of secondary metabolites and selection of reliable chemotaxonomic markers can prove helpful. In this study, the volatile fraction derived from 20 different thyme specimens was analyzed by means of headspace GC with MS detection. From the obtained chromatographic fingerprints, the diversity of the volatile fraction originating from the different thyme species clearly emerged. Identification of volatile components was based on a software library of mass spectra. There was only one common component derived from all 20 investigated thyme species, i.e., ß-linalool. For three different Thymus species, a comparison was made of the performance of the headspace extraction and hydrodistillation. Characteristic differences in composition of the volatile fraction obtained with use of these two techniques were discussed. Finally, the obtained chromatographic fingerprints of the volatile fraction were analyzed by means of a chemometric approach (principal component analysis), in order to trace similarities in their chemical composition.

  4. Coherent Optical Memory with High Storage Efficiency and Large Fractional Delay

    NASA Astrophysics Data System (ADS)

    Chen, Yi-Hsin; Lee, Meng-Jung; Wang, I.-Chung; Du, Shengwang; Chen, Yong-Fan; Chen, Ying-Cheng; Yu, Ite A.

    2013-02-01

    A high-storage efficiency and long-lived quantum memory for photons is an essential component in long-distance quantum communication and optical quantum computation. Here, we report a 78% storage efficiency of light pulses in a cold atomic medium based on the effect of electromagnetically induced transparency. At 50% storage efficiency, we obtain a fractional delay of 74, which is the best up-to-date record. The classical fidelity of the recalled pulse is better than 90% and nearly independent of the storage time, as confirmed by the direct measurement of phase evolution of the output light pulse with a beat-note interferometer. Such excellent phase coherence between the stored and recalled light pulses suggests that the current result may be readily applied to single photon wave packets. Our work significantly advances the technology of electromagnetically induced transparency-based optical memory and may find practical applications in long-distance quantum communication and optical quantum computation.

  5. High Weight-Fraction Surfactant Solubilization of Single-Wall Carbon Nanotubes in Water

    NASA Astrophysics Data System (ADS)

    Islam, M. F.; Rojas, E.; Bergey, D. M.; Johnson, A. T.; Yodh, A. G.

    2003-03-01

    We report a simple process to solubilize high weight fraction single-wall carbon nanotubes in water by nonspecific physical adsorption of sodium dodecylbenzene sulfonate. The diameter distribution of nanotubes in the dispersion, measured by Atomic Force Microscopy (AFM), showed that even at 20 mg/ml, ˜ 63 5% of single-wall carbon nanotubes bundles exfoliated into single tubes. A measure of the length distribution of the nanotubes showed that our dispersion technique reduced nanotube fragmentation. New and quantitative insight about nanotube solubilization is derived from comparisons of single tube yield, measured by AFM, as a function of surfactant type, concentration, and sonication procedure. This work has been partially supported by the NSF through the MRSEC grant DMR 00-79909, DMR-0203378, and by NASA through grant NAG8-2172.

  6. Possible hypoglycemic effect of Aloe vera L. high molecular weight fractions on type 2 diabetic patients

    PubMed Central

    Yagi, Akira; Hegazy, Sahar; Kabbash, Amal; Wahab, Engy Abd-El

    2009-01-01

    Aloe vera L. high molecular weight fractions (AHM) containing less than 10 ppm of barbaloin and polysaccharide (MW: 1000 kDa) with glycoprotein, verectin (MW: 29 kDa), were prepared by patented hyper-dry system in combination of freeze–dry technique with microwave and far infrared radiation. AHM produced significant decrease in blood glucose level sustained for 6 weeks of the start of the study. Significant decrease in triglycerides was only observed 4 weeks after treatment and continued thereafter. No deterious effects on kidney and liver functions were apparent. Treatment of diabetic patients with AHM may relief vascular complications probably via activation of immunosystem. PMID:23964163

  7. Pathological characteristics of spine metastases treated with high-dose single-fraction stereotactic radiosurgery.

    PubMed

    Katsoulakis, Evangelia; Laufer, Ilya; Bilsky, Mark; Agaram, Narasimhan P; Lovelock, Michael; Yamada, Yoshiya

    2017-01-01

    OBJECTIVE Spine radiosurgery is increasingly being used to treat spinal metastases. As patients are living longer because of the increasing efficacy of systemic agents, appropriate follow-up and posttreatment management for these patients is critical. Tumor progression after spine radiosurgery is rare; however, vertebral compression fractures are recognized as a more common posttreatment effect. The use of radiographic imaging alone posttreatment may makeit difficult to distinguish tumor progression from postradiation changes such as fibrosis. This is the largest series from a prospective database in which the authors examine histopathology of samples obtained from patients who underwent surgical intervention for presumed tumor progression or mechanical pain secondary to compression fracture. The majority of patients had tumor ablation and resulting fibrosis rather than tumor progression. The aim of this study was to evaluate tumor histopathology and characteristics of patients who underwent pathological sampling because of radiographic tumor progression, fibrosis, or collapsed vertebrae after receiving high-dose single-fraction stereotactic radiosurgery. METHODS Between January 2005 and January 2014, a total of 582 patients were treated with linear accelerator-based single-fraction (18-24 Gy) stereotactic radiosurgery. The authors retrospectively identified 30 patients (5.1%) who underwent surgical intervention for 32 lesions with vertebral cement augmentation for either mechanical pain or instability secondary to vertebral compression fracture (n = 17) or instrumentation (n = 15) for radiographic tumor progression. Radiation and surgical treatment, histopathology, and long-term outcomes were reviewed. Survival and time to recurrence were calculated using the Kaplan-Meier method. RESULTS The mean age at the time of radiosurgery was 59 years (range 36-80 years). The initial pathological diagnoses were obtained for all patients and primarily included radioresistant

  8. Internal hysteresis experienced on a high pressure syn gas compressor

    NASA Technical Reports Server (NTRS)

    Zeidan, F. Y.

    1984-01-01

    A vibration instability phenomenon experienced in operating high pressure syn gas centrifugal compressors in two ammonia plants is described. The compressors were monitored by orbit and spectrum analysis for changes from baseline readings. It is found that internal hysteresis was the major destabilizing force; however, the problem was further complicated by seal lockup at the suction end of the compressor. A coupling lockup problem and a coupling fit problem, which frettage of the shaft, are also considered as contributors to the self excited vibrations.

  9. High-pressure /sup 3/He gas scintillation neutron spectrometer

    SciTech Connect

    Derzon, M.S.; Slaughter, D.R.; Prussin, S.G.

    1985-10-01

    A high-pressure, /sup 3/He-Xe gas scintillation spectrometer has been developed for neutron spectroscopy on D-D fusion plasmas. The spectrometer exhibits an energy resolution of (121 +- 20 keV) keV (FWHM) at 2.5 MeV and an efficiency of (1.9 +- 0.4) x 10/sup -3/ (n/cm/sup 2/)/sup -1/. The contribution to the resolution (FWHM) from counting statistics is only (22 +- 3 keV) and the remainder is due predominantly to the variation of light collection efficiency with location of neutron events within the active volume of the detector.

  10. Capillary gas chromatography with two new moderately high temperature phases.

    NASA Technical Reports Server (NTRS)

    Pollock, G. E.

    1972-01-01

    Gas chromatography test results are presented for two new moderately high-temperature phases of Dexsil 400-GC with free hydroxyl end groups (uncapped) and with end groups covered by trimethyl silyl groups (capped). The two Dexsil 400-GC phases were tested for their ability to resolve N-TFA-DL-(+)-2-butyl esters and n-butyl esters, as well as fatty acid methyl esters and hydrocarbon standards. Generally the more polar uncapped phase was superior to the capped phase in all separation comparisons, except for the hydrocarbons.

  11. Capillary gas chromatography with two new moderately high temperature phases.

    NASA Technical Reports Server (NTRS)

    Pollock, G. E.

    1972-01-01

    Gas chromatography test results are presented for two new moderately high-temperature phases of Dexsil 400-GC with free hydroxyl end groups (uncapped) and with end groups covered by trimethyl silyl groups (capped). The two Dexsil 400-GC phases were tested for their ability to resolve N-TFA-DL-(+)-2-butyl esters and n-butyl esters, as well as fatty acid methyl esters and hydrocarbon standards. Generally the more polar uncapped phase was superior to the capped phase in all separation comparisons, except for the hydrocarbons.

  12. A Highly Pure Sub-Fraction of Shallot Extract With Potent in vitro Anti-Angiogenic Activity.

    PubMed

    Famil Samavati, Shima; Mohammadi-Motlagh, Hamid-Reza; Mostafaie, Ali

    2014-01-01

    Our previous studies showed that various extracts of Persian shallot (Allium hirtifolium) have anti- angiogenic effects. This study has been undertaken to isolate and identify the major effective anti- angiogeneic sub-fraction of shallot. After preparation of the 50% hydroalcoholic extract of shallot bulbs, the extract was successively fractionated into n- hexane, ethyl acetate, n- butanol and aqueous fractions. Anti-angiogenesis activity of fractions was examined by in vitro angiogenesis assay. The ethyl acetate fraction which had the most anti-angiogenesis activity was further fractionated to four sub- fractions by thin layer chromatography (TLC), silica gel column chromatography and then analyzed by High Performance TLC (HPTLC) with ethyl acetate-methanol- water as the solvent system. Our results showed that one of the four sub- fractions, as the major band in HPTLC, had the most anti- angiogenic activity. Purification and characterization of the major anti- angiogenic compound/compounds of shallot's extract may constitute one means by which diets rich in shallot confer protection against cancer and finally introduce new agents with pharmacological activities in shallot as a potential candidate in cancer therapy.

  13. A Highly Pure Sub-Fraction of Shallot Extract With Potent in vitro Anti-Angiogenic Activity

    PubMed Central

    Famil Samavati, Shima; Mohammadi-Motlagh, Hamid-Reza; Mostafaie, Ali

    2014-01-01

    Our previous studies showed that various extracts of Persian shallot (Allium hirtifolium) have anti- angiogenic effects. This study has been undertaken to isolate and identify the major effective anti- angiogeneic sub-fraction of shallot. After preparation of the 50% hydroalcoholic extract of shallot bulbs, the extract was successively fractionated into n- hexane, ethyl acetate, n- butanol and aqueous fractions. Anti-angiogenesis activity of fractions was examined by in vitro angiogenesis assay. The ethyl acetate fraction which had the most anti-angiogenesis activity was further fractionated to four sub- fractions by thin layer chromatography (TLC), silica gel column chromatography and then analyzed by High Performance TLC (HPTLC) with ethyl acetate-methanol- water as the solvent system. Our results showed that one of the four sub- fractions, as the major band in HPTLC, had the most anti- angiogenic activity. Purification and characterization of the major anti- angiogenic compound/compounds of shallot's extract may constitute one means by which diets rich in shallot confer protection against cancer and finally introduce new agents with pharmacological activities in shallot as a potential candidate in cancer therapy. PMID:25635250

  14. Reversed-phase high-performance liquid chromatography of the stable electrophoretic fractions of soil humic acids

    NASA Astrophysics Data System (ADS)

    Trubetskoi, O. A.; Trubetskaya, O. E.

    2015-02-01

    Reversed-phase high-performance liquid chromatography (RP-HPLC) has been used for the hydrophobicity analysis of soil humic acids and their stable electrophoretic fractions A, B, and C + D preliminarily prepared by the combination of gel permeation chromatography on Sephadex with polyacrylamide gel electrophoresis. In two humic acid preparations of different genesis, the electrophoretic fraction A of the larger molecular size was the most hydrophobic (60-73% of the fraction was irreversibly adsorbed on a hydrophobic reversed-phase (RF) column C18), and the fraction C + D of the smallest molecular size was the most hydrophilic. The fraction B of medium size occupied an intermediate position (33-47% of the fraction was irreversibly adsorbed on the column). The use of RP-HPLC allowed for the first time detecting the hydrophobic electrophoretic fraction A of the largest molecular size mainly composed of aliphatic long-chained hydrocarbon, protein, and carbohydrate fragments in soil humic acids. Data on the degree of hydrophobicity and the earlier obtained physicochemical characteristics of stable electrophoretic fractions are discussed in terms of the supramolecular and macromolecular structure of soil humic acids.

  15. High rate of methane leakage from natural gas production

    NASA Astrophysics Data System (ADS)

    Balcerak, Ernie

    2013-10-01

    Natural gas production is growing as the United States seeks domestic sources of relatively clean energy. Natural gas combustion produces less carbon dioxide emissions than coal or oil for the amount of energy produced. However, one source of concern is that some natural gas leaks to the atmosphere from the extraction point, releasing methane, a potent greenhouse gas.

  16. Prospects for high pressure imaging gas scintillation drift chambers

    NASA Technical Reports Server (NTRS)

    Edberg, T. K.; Parsons, A.; Sadoulet, B.; Weiss, S.; Wilkerson, J.; Smith, G.

    1992-01-01

    The current developmental status and future potential of a promising hard X-ray and gamma ray detector are presented: the high pressure xenon gas scintillation imaging drift chamber. A scheme for reading out the scintillation light waveshifting fibers, which allows operation at pressures at least as high as 20 atmospheres, is used. This technique combines excellent spatial resolution (approximately 200 rms allowing 1.5 arcminute mapping resolution), very good energy resolution (within a factor of three of Ge detectors), good time resolution (approximately 100 ns), and extremely high sensitivity because of excellent background rejection capabilities; it also offers possibilities for extrapolation to large area detectors. Results from tests with a prototype chamber are presented. The design of a scientific instrument for a balloon flight planned in 1995 is described. This instrument, the Scintillation Imaging Gas filled Hard X-ray Telescope (SIGHT), is optimized for detecting 30 to 300 keV X-rays. It has an active area of 1140 sq cm, with a stopping power of between 2.0 and 2.7 g/sq cm of xenon at 20 atmospheres. Possible future evolutionary tracks of the technology leading to innovative satellite applications are discussed.

  17. Respiratory gas exchange of high altitude adapted chick embryos

    NASA Technical Reports Server (NTRS)

    Wangensteen, O. D.; Rahn, H.; Burton, R. R.; Smith, A. H.

    1974-01-01

    Study of gas exchange by embryos from chickens acclimatized to an altitude of 3800 m. The oxygen partial pressure and carbon dioxide partial pressure differences across the egg shell were measured and found to be less than the values previously reported for sea-level eggs by about a factor of two. Further measurements of embryonic oxygen consumption and shell conductivity to oxygen indicated that, compared to eggs at sea level, oxygen consumption was reduced by a factor of 0.58 while conductivity to oxygen was increased only by a factor of 1.07 in the high-altitude eggs. These independent measurements predict the change in oxygen partial pressure across the egg shell of the high-altitude eggs to be only 0.54 times that of sea-level eggs; the directly measured factor was 0.53. The authors conclude that at high altitude, a major adaptation of the chick embryo is a reduced metabolism which decreases the change in oxygen partial pressure across the egg shell since its gas conductivity remains essentially unchanged.

  18. High resolution dissociative electron attachment to gas phase adenine

    SciTech Connect

    Huber, D.; Beikircher, M.; Denifl, S.; Zappa, F.; Matejcik, S.; Bacher, A.; Grill, V.; Maerk, T. D.; Scheier, P.

    2006-08-28

    The dissociative electron attachment to the gas phase nucleobase adenine is studied using two different experiments. A double focusing sector field mass spectrometer is utilized for measurements requiring high mass resolution, high sensitivity, and relative ion yields for all the fragment anions and a hemispherical electron monochromator instrument for high electron energy resolution. The negative ion mass spectra are discussed at two different electron energies of 2 and 6 eV. In contrast to previous gas phase studies a number of new negative ions are discovered in the mass spectra. The ion efficiency curves for the negative ions of adenine are measured for the electron energy range from about 0 to 15 eV with an electron energy resolution of about 100 meV. The total anion yield derived via the summation of all measured fragment anions is compared with the total cross section for negative ion formation measured recently without mass spectrometry. For adenine the shape of the two cross section curves agrees well, taking into account the different electron energy resolutions; however, for thymine some peculiar differences are observed.

  19. MAGNETIZED GAS IN THE SMITH HIGH VELOCITY CLOUD

    SciTech Connect

    Hill, Alex S.; McClure-Griffiths, Naomi M.; Mao, S. A.; Benjamin, Robert A.; Lockman, Felix J. E-mail: naomi.mcclure-griffiths@csiro.au E-mail: benjamir@uww.edu

    2013-11-01

    We report the first detection of magnetic fields associated with the Smith High Velocity Cloud. We use a catalog of Faraday rotation measures toward extragalactic radio sources behind the Smith Cloud, new H I observations from the Robert C. Byrd Green Bank Telescope, and a spectroscopic map of Hα from the Wisconsin H-Alpha Mapper Northern Sky Survey. There are enhancements in rotation measure (RM) of ≈100 rad m{sup –2} which are generally well correlated with decelerated Hα emission. We estimate a lower limit on the line-of-sight component of the field of ≈8 μG along a decelerated filament; this is a lower limit due to our assumptions about the geometry. No RM excess is evident in sightlines dominated by H I or Hα at the velocity of the Smith Cloud. The smooth Hα morphology of the emission at the Smith Cloud velocity suggests photoionization by the Galactic ionizing radiation field as the dominant ionization mechanism, while the filamentary morphology and high (≈1 Rayleigh) Hα intensity of the lower-velocity magnetized ionized gas suggests an ionization process associated with shocks due to interaction with the Galactic interstellar medium. The presence of the magnetic field may contribute to the survival of high velocity clouds like the Smith Cloud as they move from the Galactic halo to the disk. We expect these data to provide a test for magnetohydrodynamic simulations of infalling gas.

  20. Respiratory gas exchange of high altitude adapted chick embryos

    NASA Technical Reports Server (NTRS)

    Wangensteen, O. D.; Rahn, H.; Burton, R. R.; Smith, A. H.

    1974-01-01

    Study of gas exchange by embryos from chickens acclimatized to an altitude of 3800 m. The oxygen partial pressure and carbon dioxide partial pressure differences across the egg shell were measured and found to be less than the values previously reported for sea-level eggs by about a factor of two. Further measurements of embryonic oxygen consumption and shell conductivity to oxygen indicated that, compared to eggs at sea level, oxygen consumption was reduced by a factor of 0.58 while conductivity to oxygen was increased only by a factor of 1.07 in the high-altitude eggs. These independent measurements predict the change in oxygen partial pressure across the egg shell of the high-altitude eggs to be only 0.54 times that of sea-level eggs; the directly measured factor was 0.53. The authors conclude that at high altitude, a major adaptation of the chick embryo is a reduced metabolism which decreases the change in oxygen partial pressure across the egg shell since its gas conductivity remains essentially unchanged.

  1. High density lipoprotein plasma fractions inhibit aortic fatty streaks in cholesterol-fed rabbits.

    PubMed

    Badimon, J J; Badimon, L; Galvez, A; Dische, R; Fuster, V

    1989-03-01

    The effects of in vivo administration of high density lipoprotein-very high density lipoprotein (HDL-VHDL) on the development of aortic fatty streaks were studied in cholesterol-fed rabbits. The rabbits received a 0.5% cholesterol-rich diet for 8 weeks. During this period, the HDL-VHDL group was intravenously administered with 50 mg/week of homologous HDL-VHDL protein; the control group received normal saline (0.9% NaCl). HDL-VHDL fraction was obtained at density range 1.063 to 1.25 gm/ml by ultracentrifugation of normal rabbit plasma. Along the study, plasma lipid levels followed a similar profile in both groups. At the completion of the study, atherosclerotic-like lipid-rich lesions covered 37.9 +/- 6% (X +/- SEM) of the intimal aortic surface in the control group, and 14.9 +/- 2.1% in the treated group (p less than 0.001). The values of total and free cholesterol, esterified cholesterol, and phospholipids deposited within vessel wall were significantly lower in the aortas of the HDL-VHDL treated group than those in the control group. Cholesterol accumulation in the livers was also significantly lower (p less than 0.01) in the treated group than in the control. We concluded that administration of homologous HDL-VHDL lipoprotein fraction to cholesterol-fed rabbits, dramatically inhibited the extent of aortic fatty streaks and lowered lipid deposition in the arterial wall and liver without modification of the plasma lipid levels.

  2. An Increasing Stellar Baryon Fraction in Bright Galaxies at High Redshift

    NASA Astrophysics Data System (ADS)

    Finkelstein, Steven L.; Song, Mimi; Behroozi, Peter; Somerville, Rachel S.; Papovich, Casey; Milosavljević, Miloš; Dekel, Avishai; Narayanan, Desika; Ashby, Matthew L. N.; Cooray, Asantha; Fazio, Giovanni G.; Ferguson, Henry C.; Koekemoer, Anton M.; Salmon, Brett; Willner, S. P.

    2015-12-01

    Recent observations have shown that the characteristic luminosity of the rest-frame ultraviolet (UV) luminosity function does not significantly evolve at 4 < z < 7 and is approximately {M}{UV}*˜ -21. We investigate this apparent non-evolution by examining a sample of 173 bright, MUV < -21 galaxies at z = 4-7, analyzing their stellar populations and host halo masses. Including deep Spitzer/IRAC imaging to constrain the rest-frame optical light, we find that {M}{UV}* galaxies at z = 4-7 have similar stellar masses of log(M/M⊙) = 9.6-9.9 and are thus relatively massive for these high redshifts. However, bright galaxies at z = 4-7 are less massive and have younger inferred ages than similarly bright galaxies at z = 2-3, even though the two populations have similar star formation rates and levels of dust attenuation for a fixed dust-attenuation curve. Matching the abundances of these bright z = 4-7 galaxies to halo mass functions from the Bolshoi ΛCDM simulation implies that the typical halo masses in ˜ {M}{{UV}}* galaxies decrease from log(Mh/M⊙) = 11.9 at z = 4 to log(Mh/M⊙) = 11.4 at z = 7. Thus, although we are studying galaxies at a similar stellar mass across multiple redshifts, these galaxies live in lower mass halos at higher redshift. The stellar baryon fraction in ˜ {M}{{UV}}* galaxies in units of the cosmic mean Ωb/Ωm rises from 5.1% at z = 4 to 11.7% at z = 7; this evolution is significant at the ˜3σ level. This rise does not agree with simple expectations of how galaxies grow, and implies that some effect, perhaps a diminishing efficiency of feedback, is allowing a higher fraction of available baryons to be converted into stars at high redshifts.

  3. Evidence for high-temperature fractionation of lithium isotopes during differentiation of the Moon

    NASA Astrophysics Data System (ADS)

    Day, James M. D.; Qiu, Lin; Ash, Richard D.; McDonough, William F.; Teng, Fang-Zhen; Rudnick, Roberta L.; Taylor, Lawrence A.

    2016-06-01

    Lithium isotope and abundance data are reported for Apollo 15 and 17 mare basalts and the LaPaz low-Ti mare basalt meteorites, along with lithium isotope data for carbonaceous, ordinary, and enstatite chondrites, and chondrules from the Allende CV3 meteorite. Apollo 15 low-Ti mare basalts have lower Li contents and lower δ7Li (3.8 ± 1.2‰; all uncertainties are 2 standard deviations) than Apollo 17 high-Ti mare basalts (δ7Li = 5.2 ± 1.2‰), with evolved LaPaz mare basalts having high Li contents, but similar low δ7Li (3.7 ± 0.5‰) to Apollo 15 mare basalts. In low-Ti mare basalt 15555, the highest concentrations of Li occur in late-stage tridymite (>20 ppm) and plagioclase (11 ± 3 ppm), with olivine (6.1 ± 3.8 ppm), pyroxene (4.2 ± 1.6 ppm), and ilmenite (0.8 ± 0.7 ppm) having lower Li concentrations. Values of δ7Li in low- and high-Ti mare basalt sources broadly correlate negatively with 18O/16O and positively with 56Fe/54Fe (low-Ti: δ7Li ≤4‰; δ56Fe ≤0.04‰; δ18O ≥5.7‰; high-Ti: δ7Li >6‰ δ56Fe >0.18‰ δ18O <5.4‰). Lithium does not appear to have acted as a volatile element during planetary formation, with subequal Li contents in mare basalts compared with terrestrial, martian, or vestan basaltic rocks. Observed Li isotopic fractionations in mare basalts can potentially be explained through large-degree, high-temperature igneous differentiation of their source regions. Progressive magma ocean crystallization led to enrichment in Li and δ7Li in late-stage liquids, probably as a consequence of preferential retention of 7Li and Li in the melt relative to crystallizing solids. Lithium isotopic fractionation has not been observed during extensive differentiation in terrestrial magmatic systems and may only be recognizable during extensive planetary magmatic differentiation under volatile-poor conditions, as expected for the lunar magma ocean. Our new analyses of chondrites show that they have δ7Li ranging between -2.5‰ and 4

  4. Mass flow rate measurements in gas-liquid flows by means of a venturi or orifice plate coupled to a void fraction sensor

    SciTech Connect

    Oliveira, Jorge Luiz Goes; Passos, Julio Cesar

    2009-01-15

    Two-phase flow measurements were carried out using a resistive void fraction meter coupled to a venturi or orifice plate. The measurement system used to estimate the liquid and gas mass flow rates was evaluated using an air-water experimental facility. Experiments included upward vertical and horizontal flow, annular, bubbly, churn and slug patterns, void fraction ranging from 2% to 85%, water flow rate up to 4000 kg/h, air flow rate up to 50 kg/h, and quality up to almost 10%. The fractional root mean square (RMS) deviation of the two-phase mass flow rate in upward vertical flow through a venturi plate is 6.8% using the correlation of Chisholm (D. Chisholm, Pressure gradients during the flow of incompressible two-phase mixtures through pipes, venturis and orifice plates, British Chemical Engineering 12 (9) (1967) 454-457). For the orifice plate, the RMS deviation of the vertical flow is 5.5% using the correlation of Zhang et al. (H.J. Zhang, W.T. Yue, Z.Y. Huang, Investigation of oil-air two-phase mass flow rate measurement using venturi and void fraction sensor, Journal of Zhejiang University Science 6A (6) (2005) 601-606). The results show that the flow direction has no significant influence on the meters in relation to the pressure drop in the experimental operation range. Quality and slip ratio analyses were also performed. The results show a mean slip ratio lower than 1.1, when bubbly and slug flow patterns are encountered for mean void fractions lower than 70%. (author)

  5. Completion design for high capacity offshore gas wells

    SciTech Connect

    Hartley, R.

    1982-01-01

    Sarawak Shell Berhad currently is developing 2 offshore gas fields to supply ca 1200 MMSCFD to a LNG plant being built at Bintulu, Sarawak. Both E11 and F23 are carbonate build-ups with high productivities, but because of their relative shallow depth, only moderate reservoir pressure. The produced gas is lean with carbon dioxide contents up to 7.3% and hydrogen sulfide contents ca 8 ppm. Because the wells are off shore, there is an increased risk caused by the proximity of other wells and the possibility of platform damage. Also, being off shore means high costs for drilling, compression, and workover. This work discusses the completion design developed to cope with these conditions. Safety considerations, the prevention of corrosion, and tubing stress analysis are discussed. The final design uses 7-in. tubulars, including 13 Cr steel at points where corrosion may be severe and utilizes a fire-resistant christmas tree and wellhead design. A further point of interest is that a study of possible blowout and cratering conditions was made to predict the maximum crater depth. The subsurface safety valve is set below this depth.

  6. Improved High-Voltage Gas Isolator for Ion Thruster

    NASA Technical Reports Server (NTRS)

    Banks, Bruce

    2007-01-01

    A report describes an improved high-voltage isolator for preventing electrical discharge along the flow path of a propellant gas being fed from a supply at a spacecraft chassis electrical potential to an ion thruster at a potential as high as multiple kilovolts. The isolator must survive launch vibration and must remain electrically nonconductive for thousands of hours under conditions that, in the absence of proper design, would cause formation of electrically conductive sputtered metal, carbon, and/or decomposed hydrocarbons on its surfaces. The isolator includes an alumina cylinder containing a spiral channel filled with a porous medium made from alumina microbeads fired together with an alumina slurry. Connections to gas-transport tubes are made at both ends of the alumina cylinder by means of metal caps containing fine-mesh screens to prevent passage of loose alumina particles. The outer surface of the alumina cylinder is convoluted to lengthen the electrical path between the metal caps and to afford shadow shielding to minimize the probability of formation of a continuous deposit that would electrically connect the ends. A flanged cylindrical metal cap that surrounds the alumina cylinder without touching one of the ends provides additional shadow shielding.

  7. High-speed gears for gas turbine drive

    SciTech Connect

    Kane, J.

    1995-06-01

    Recently, Lufkin Industries, Power Transmission Div., full-load tested a high-speed gear designed to couple a 50 Hz electric power generator to a GE LM6000 gas turbine for a power generation project in Australia. The gear is rated 52.2 MW to match the output of the LM6000 gas turbine believed to be one of the largest gear testing operations for this type and size of gear. Each gear drive manufactured by Lufkin is full-speed tested to verify its performance. Tests performed on high-speed units duplicate field conditions, as closely as possible, in order to verify critical speed analysis results and new bearing designs, if used. Lufkin also tests design techniques used in the development of new products. The finite element analysis performed to predict housing deflection in the thrust bearing area of a new extruder driveline was verified by testing of a prototype unit housing. Recently, housing structure stiffness and natural frequencies were predicted and verified on the test stand for some 50 MW vertically offset gear units. A complete data acquisition system is used to gather data from bearing, inlet and drain temperature monitoring points. The temperature monitoring system will accommodate type T,K,J, and E thermocouples and platinum and nickel RTDs.

  8. Molecular dynamics simulations of high speed rarefied gas flows

    NASA Astrophysics Data System (ADS)

    Dongari, Nishanth; Zhang, Yonghao; Reese, Jason M.

    2012-11-01

    To understand the molecular behaviour of gases in high speed rarefied conditions, we perform molecular dynamics (MD) numerical experiments using the open source code Open FOAM. We use shear-driven Couette flows as test cases, where the two parallel plates are moving with a speed of Uw in opposite directions with their temperatures set to Tw. The gas rarefaction conditions vary from slip to transition, and compressibility conditions vary from low speed isothermal to hypersonic flow regimes, i.e. Knudsen number (Kn) from 0.01 to 1 and Mach number (Ma) from 0.05 to 10. We measure the molecular velocity distribution functions, the spatial variation of gas mean free path profiles and other macroscopic properties. Our MD results convey that flow properties in the near-wall non-equilibrium region do not merely depend on Kn, but they are also significantly affected by Ma. These results may yield new insight into diffusive transport in rarefied gases at high speeds.

  9. Progress toward steady-state tokamak operation exploiting the high bootstrap current fraction regime

    NASA Astrophysics Data System (ADS)

    Ren, Q. L.; Garofalo, A. M.; Gong, X. Z.; Holcomb, C. T.; Lao, L. L.; McKee, G. R.; Meneghini, O.; Staebler, G. M.; Grierson, B. A.; Qian, J. P.; Solomon, W. M.; Turnbull, A. D.; Holland, C.; Guo, W. F.; Ding, S. Y.; Pan, C. K.; Xu, G. S.; Wan, B. N.

    2016-06-01

    Recent DIII-D experiments have increased the normalized fusion performance of the high bootstrap current fraction tokamak regime toward reactor-relevant steady state operation. The experiments, conducted by a joint team of researchers from the DIII-D and EAST tokamaks, developed a fully noninductive scenario that could be extended on EAST to a demonstration of long pulse steady-state tokamak operation. Improved understanding of scenario stability has led to the achievement of very high values of βp and βN , despite strong internal transport barriers. Good confinement has been achieved with reduced toroidal rotation. These high βp plasmas challenge the energy transport understanding, especially in the electron energy channel. A new turbulent transport model, named TGLF-SAT1, has been developed which improves the transport prediction. Experiments extending results to long pulse on EAST, based on the physics basis developed at DIII-D, have been conducted. More investigations will be carried out on EAST with more additional auxiliary power to come online in the near term.

  10. Progress toward steady-state tokamak operation exploiting the high bootstrap current fraction regime

    SciTech Connect

    Ren, Q. L.; Garofalo, A. M.; Gong, X. Z.; Holcomb, C. T.; Lao, L. L.; McKee, G. R.; Meneghini, O.; Staebler, G. M.; Grierson, B. A.; Qian, J. P.; Solomon, W. M.; Turnbull, A. D.; Holland, C.; Guo, W. F.; Ding, S. Y.; Pan, C. K.; Xu, G. S.; Wan, B. N.

    2016-06-20

    Recent DIII-D experiments have increased the normalized fusion performance of the high bootstrap current fraction tokamak regime toward reactor-relevant steady state operation. The experiments, conducted by a joint team of researchers from the DIII-D and EAST tokamaks, developed a fully noninductive scenario that could be extended on EAST to a demonstration of long pulse steady-state tokamak operation. Improved understanding of scenario stability has led to the achievement of very high values of βp and βN despite strong ITBs. Good confinement has been achieved with reduced toroidal rotation. These high βp plasmas challenge the energy transport understanding, especially in the electron energy channel. A new turbulent transport model, named 2 TGLF-SAT1, has been developed which improves the transport prediction. Experiments extending results to long pulse on EAST, based on the physics basis developed at DIII-D, have been conducted. Finally, more investigations will be carried out on EAST with more additional auxiliary power to come online in the near term.

  11. Progress toward steady-state tokamak operation exploiting the high bootstrap current fraction regime

    DOE PAGES

    Ren, Q. L.; Garofalo, A. M.; Gong, X. Z.; ...

    2016-06-20

    Recent DIII-D experiments have increased the normalized fusion performance of the high bootstrap current fraction tokamak regime toward reactor-relevant steady state operation. The experiments, conducted by a joint team of researchers from the DIII-D and EAST tokamaks, developed a fully noninductive scenario that could be extended on EAST to a demonstration of long pulse steady-state tokamak operation. Improved understanding of scenario stability has led to the achievement of very high values of βp and βN despite strong ITBs. Good confinement has been achieved with reduced toroidal rotation. These high βp plasmas challenge the energy transport understanding, especially in the electronmore » energy channel. A new turbulent transport model, named 2 TGLF-SAT1, has been developed which improves the transport prediction. Experiments extending results to long pulse on EAST, based on the physics basis developed at DIII-D, have been conducted. Finally, more investigations will be carried out on EAST with more additional auxiliary power to come online in the near term.« less

  12. LIMITS TO THE FRACTION OF HIGH-ENERGY PHOTON EMITTING GAMMA-RAY BURSTS

    SciTech Connect

    Akerlof, Carl W.; Zheng, WeiKang

    2013-02-20

    After almost four years of operation, the two instruments on board the Fermi Gamma-ray Space Telescope have shown that the number of gamma-ray bursts (GRBs) with high-energy photon emission above 100 MeV cannot exceed roughly 9% of the total number of all such events, at least at the present detection limits. In a recent paper, we found that GRBs with photons detected in the Large Area Telescope have a surprisingly broad distribution with respect to the observed event photon number. Extrapolation of our empirical fit to numbers of photons below our previous detection limit suggests that the overall rate of such low flux events could be estimated by standard image co-adding techniques. In this case, we have taken advantage of the excellent angular resolution of the Swift mission to provide accurate reference points for 79 GRB events which have eluded any previous correlations with high-energy photons. We find a small but significant signal in the co-added field. Guided by the extrapolated power-law fit previously obtained for the number distribution of GRBs with higher fluxes, the data suggest that only a small fraction of GRBs are sources of high-energy photons.

  13. Properties of the highly ionized disk and halo gas toward two distant high-latitude stars

    NASA Technical Reports Server (NTRS)

    Savage, Blair D.; Sembach, K. R.

    1994-01-01

    Goddard High Resolution Spectrograph (GHRS) intermediate -resolution observations of S III, Si III, Al III, Si IV, C IV, and N V absorption along the sight lines to HD 18100 (l = 217.9 deg, b = -62.7, d = 3.1 kpc, z = -2.8 kpc) and HD 100340 (l = 258.9 deg, b = +61.2 deg, d = 5.3 kpc, z = 4.6 kpc) are presented. These small science aperture spectra have resolutions ranging from 11 to 20 km/s full width at half maximum (FWHM) and S/N from 30 to 65 per diode substep. Strong absorption by moderately and highly ionized gas is seen in each direction. The absorption in the direction of the south Galactic polar region (HD 18100) is kinematically simple, while the absorption in the direction of north Galactic polar region (HD 100304) is kinematically complex. In each case the absorption by the highly ionized gas lies within the velocity range of absorption by neutral and weakly ionized gas. Along each sight line, the velocity dispersion determined from the unsaturated absorption lines increases with the energy required to create each ion. The logarithmic column densities for Al III, Si IV, C IV, and N V are log N(atoms/sq cm = 12.71, 13.10, 13.58, and 12.75 toward HD 18100 and log N = 12.88, 13.31, 13.83, and 13.04 toward HD 100340. Average ionic ratios among these species are very similar along the two sight lines. Differences in profile shape between the absorption for AL II, Si IV, C IV, and N V provide additional support for the claim of Savage, Sembach, & Cardelli (1994) that there exists two types of highly ionized gas in the interstellar medium. One type of highly ionized gas is responsible for the structured Si IV absorption and part of the C IV absorption. In this gas N(C IV)/N(Si IV) approximately 3.0 and N(C IV)/N(N V) greater than 6. The absorption by this gas seems to be associated with some type of self-regulating interface or mixing layer between the warm and hot interstellar medium. The other type of highly ionized gas is responsible for most of the N V

  14. Antihepatoma activity of Artocarpus communis is higher in fractions with high artocarpin content.

    PubMed

    Tzeng, Cheng-Wei; Yen, Feng-Lin; Lin, Liang-Tzung; Lee, Chiang-Wen; Yen, Ming-Hong; Tzeng, Wen-Sheng; Lin, Chun-Ching

    2014-01-01

    Extracts from natural plants have been used in traditional medicine for many centuries worldwide. Artocarpus communis is one such plant that has been used to treat liver cirrhosis, hypertension, and diabetes. To our knowledge, this study is the first to investigate the antihepatoma activity of A. communis toward HepG2 and PLC/PRF/5 cells and the first to explore the relationship between antihepatoma activity and the active compound artocarpin content in different fractions of A. communis. A. communis methanol extract and fractions induced dose-dependent reduction of tumor cell viability. DNA laddering analysis revealed that A. communis extract and fractions did not induce apoptosis in HepG2 and PLC/PRF/5 cells. Instead, acridine orange staining revealed that A. communis triggered autophagic cell death in a dose-dependent manner. The antihepatoma activity of A. communis is attributable to artocarpin. The fractions with the highest artocarpin content were also the fractions with the highest antihepatoma activity in the following order: dichloromethane fraction > methanol extract > ethyl acetate fraction > n-butanol fraction > n-hexane fraction. Taken together, A. communis showed antihepatoma activity through autophagic cell death. The effect was related to artocarpin content. Artocarpin could be considered an indicator of the anticancer potential of A. communis extract.

  15. Antihepatoma Activity of Artocarpus communis Is Higher in Fractions with High Artocarpin Content

    PubMed Central

    Tzeng, Cheng-Wei; Yen, Feng-Lin; Lee, Chiang-Wen; Yen, Ming-Hong; Tzeng, Wen-Sheng; Lin, Chun-Ching

    2014-01-01

    Extracts from natural plants have been used in traditional medicine for many centuries worldwide. Artocarpus communis is one such plant that has been used to treat liver cirrhosis, hypertension, and diabetes. To our knowledge, this study is the first to investigate the antihepatoma activity of A. communis toward HepG2 and PLC/PRF/5 cells and the first to explore the relationship between antihepatoma activity and the active compound artocarpin content in different fractions of A. communis. A. communis methanol extract and fractions induced dose-dependent reduction of tumor cell viability. DNA laddering analysis revealed that A. communis extract and fractions did not induce apoptosis in HepG2 and PLC/PRF/5 cells. Instead, acridine orange staining revealed that A. communis triggered autophagic cell death in a dose-dependent manner. The antihepatoma activity of A. communis is attributable to artocarpin. The fractions with the highest artocarpin content were also the fractions with the highest antihepatoma activity in the following order: dichloromethane fraction > methanol extract > ethyl acetate fraction > n-butanol fraction > n-hexane fraction. Taken together, A. communis showed antihepatoma activity through autophagic cell death. The effect was related to artocarpin content. Artocarpin could be considered an indicator of the anticancer potential of A. communis extract. PMID:25133268

  16. Fractionation of whey proteins with high-capacity superparamagnetic ion-exchangers.

    PubMed

    Heebøll-Nielsen, Anders; Justesen,