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Sample records for high gas fractions

  1. 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

  2. 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

  3. 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.

  4. 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. PMID:25532672

  5. 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.

  6. 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.

  7. 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

  8. 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

  9. 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

    2016-09-01

    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. PMID:27485151

  10. Challenge in the speciation of nitrogen-containing compounds in heavy petroleum fractions by high temperature comprehensive two-dimensional gas chromatography.

    PubMed

    Dutriez, Thomas; Borras, Julie; Courtiade, Marion; Thiébaut, Didier; Dulot, Hugues; Bertoncini, Fabrice; Hennion, Marie-Claire

    2011-05-27

    Extending the knowledge related to nitrogen-containing compounds presents an important interest for the petroleum industry due to their implication in atmosphere pollution as well as their inhibitive or refractive behaviour towards hydroprocessing. Most of the nitrogenated species are concentrated in heavy petroleum cuts. As no analytical method is resolutive enough for these heavy cuts, particularly regarding nitrogen-containing compounds, a new approach is needed. For this reason, this study focuses on the development of a GC×GC technique, through the hyphenation of a specific NCD detector with a GC×GC system at high temperature. The performances of highly polar thermally stable stationary phases, in particular those composed of promising ionic liquids, were monitored in normal and reversed configurations. Subsequently, after the extraction of neutral or basic compounds by adsorption on an ion-exchange resin, a first quantitative determination was attempted for a straight-run and a direct coal liquefaction vacuum gas oils. This study led to a better understanding of the behaviour of highly aromatic N-compounds by 2D-GC including an ionic liquid phase as well as a deeper N-characterization of heavy petroleum fractions.

  11. Improving fractionation lowers butane sulfur level at Saudi gas plant

    SciTech Connect

    Harruff, L.G.; Martinie, G.D.; Rahman, A.

    1998-10-12

    Increasing the debutanizer reflux/feed ratio to improve fractionation at an eastern Saudi Arabian NGL plant reduced high sulfur in the butane product. The sulfur resulted from dimethyl sulfide (DMS) contamination in the feed stream from an offshore crude-oil reservoir in the northern Arabian Gulf. The contamination is limited to two northeastern offshore gas-oil separation plants operated by Saudi Arabian Oil Co. (Saudi Aramco) and, therefore, cannot be transported to facilities outside the Eastern Province. Two technically acceptable solutions for removing this contaminant were investigated: 13X molecular-sieve adsorption of the DMS and increased fractionation efficiency. The latter would force DMS into the debutanizer bottoms.

  12. A multi-dimensional high performance liquid chromatographic method for fingerprinting polycyclic aromatic hydrocarbons and their alkyl-homologs in the heavy gas oil fraction of Alaskan North Slope crude.

    PubMed

    Saravanabhavan, Gurusankar; Helferty, Anjali; Hodson, Peter V; Brown, R Stephen

    2007-07-13

    We report an offline multi-dimensional high performance liquid chromatography (HPLC) technique for the group separation and analysis of PAHs in a heavy gas oil fraction (boiling range 287-481 degrees C). Waxes present in the heavy gas oil fraction were precipitated using cold acetone at -20 degrees C. Recovery studies showed that the extract contained 93% (+/-1%; n=3) of the PAHs that were originally present while the wax residue contained only 6% (+/-0.5%; n=3). PAHs present in the extract were fractionated, based on number of rings, into five fractions using a semi-preparative silica column (normal-phase HPLC). These fractions were analyzed using reverse-phase HPLC (RP-HPLC) coupled to a diode array detector (DAD). The method separated alkyl and un-substituted PAHs on two reverse-phase columns in series using an acetonitrile/water mobile phase. UV spectra of the chromatographic peaks were used to differentiate among PAH groups. Further characterization of PAHs within a given group to determine the substituent alkyl carbon number used retention time matching with a suite of alkyl-PAH standards. Naphthalene, dibenzothiophene, phenanthrene and fluorene and their C1-C4 alkyl isomers were quantified. The concentrations of these compounds obtained using the current method were compared with that of a GC-MS analysis obtained from an independent oil chemistry laboratory. PMID:17482627

  13. 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.

  14. Cluster gas fraction as a test of gravity

    NASA Astrophysics Data System (ADS)

    Li, Baojiu; He, Jian-hua; Gao, Liang

    2016-02-01

    We propose a new cosmological test of gravity, by using the observed mass fraction of X-ray-emitting gas in massive galaxy clusters. The cluster gas fraction, believed to be a fair sample of the average baryon fraction in the Universe, is a well-understood observable, which has previously mainly been used to constrain background cosmology. In some modified gravity models, such as f(R) gravity, gas temperature in a massive cluster is determined by the effective mass (the mass that would have produced the same gravitational effect assuming standard gravity as the cluster actually does in f(R) gravity) of that cluster, which can be larger than its true mass. On the other hand, X-ray luminosity is determined by the true gas density, which in both modified gravity and Λ-cold-dark-matter models depends mainly on Ωb/Ωm and hence the true total cluster mass. As a result, the standard practice of combining gas temperatures and X-ray surface brightnesses of clusters to infer their gas fractions can, in modified gravity models, lead to a larger - in f(R) gravity this can be 1/3 larger - value of Ωb/Ωm than that inferred from other observations such as the cosmic microwave background. Our quick calculation shows that the Hu-Sawicki n = 1 f(R) model with |bar{f}_{R0}|=5× 10^{-5} is in tension with the gas fraction data of the 42 clusters analysed by Allen et al. We also discuss the implications for other modified gravity models.

  15. High-performance liquid chromatography fractionation using a silver-modified column followed by two-dimensional comprehensive gas chromatography for detailed group-type characterization of oils and oil pollutions.

    PubMed

    Mao, Debin; Van De Weghe, Hendrik; Diels, Ludo; De Brucker, Nicole; Lookman, Richard; Vanermen, Guido

    2008-01-25

    Successful remediation of oil-contaminated soils relies on a sound preceding characterization of the oil chemical composition and physicochemical properties. Comprehensive two-dimensional gas chromatography with flame ionization detection (GCxGC/FID) is known to be very suitable for the analysis of complex samples such as petroleum hydrocarbons. However, in spite of the high-separation power offered by GCxGC, it fails to completely separate certain hydrocarbon groups in petroleum hydrocarbon mixtures. This hampers a detailed chemical composition assessment which can lead to wrong conclusions on the behaviour of the oil in soil systems, e.g. biological degradability and water solubility. This paper describes a high-performance liquid chromatography (HPLC) system with a silver-modified column as a prefractionation step to GCxGC to improve chemical identification. With HPLC, the petroleum hydrocarbons were baseline separated into a saturated fraction (including alkanes and cycloalkanes) and an unsaturated fraction (including alkenes, aromatic hydrocarbons and heterocyclic components). Each fraction eluted in a small time window limiting the dilution caused by HPLC. The two fractions were collected and quantitatively analyzed with GCxGC/FID. Cold splitless injection of 4 microl was adopted to compensate the dilution caused by the prefractionation step. With oil-spiked soil samples, a good reproducibility was obtained (RSD=3.5%; n=7) and the recovery was satisfactory (87.7%).

  16. 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.

  17. 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.

  18. A transient method for measuring the gas volume fraction in a mixed gas-liquid flow using acoustic resonance spectroscopy

    NASA Astrophysics Data System (ADS)

    Chen, Dehua; Wang, Xiuming; Che, Chengxuan; Cong, Jiansheng; Xu, Delong; Wang, Xiaomin

    2010-08-01

    In this paper, the feasibility of measuring the gas volume fraction in a mixed gas-liquid flow by using an acoustic resonant spectroscopy (ARS) method in a transient way is studied theoretically and experimentally. Firstly, the effects of sizes and locations of a single air bubble in a cylindrical cavity with two open ends on resonant frequencies are investigated numerically. Then, a transient measurement system for ARS is established, and the trends of the resonant frequencies (RFs) and resonant amplitudes (RAs) in the cylindrical cavity with gas flux inside are investigated experimentally. The measurement results by the proposed transient method are compared with those by steady-state ones and numerical ones. The numerical results show that the RFs of the cavity are highly sensitive to the volume of the single air bubble. A tiny bubble volume perturbation may cause a prominent RF shift even though the volume of the air bubble is smaller than 0.1% of that of the cavity. When the small air bubble moves, the RF shift will change and reach its maximum value as it is located at the middle of the cavity. As the gas volume fraction of the two-phase flow is low, both the RFs and RAs from the measurement results decrease dramatically with the increasing gas volume, and this decreasing trend gradually becomes even as the gas volume fraction increases further. These experimental results agree with the theoretical ones qualitatively. In addition, the transient method for ARS is more suitable for measuring the gas volume fraction with randomness and instantaneity than the steady-state one, because the latter could not reflect the random and instant characteristics of the mixed fluid due to the time consumption for frequency sweeping. This study will play a very important role in the quantitative measurement of the gas volume fraction of multiphase flows.

  19. 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)

  20. ENHANCED DENSE GAS FRACTION IN ULTRALUMINOUS INFRARED GALAXIES

    SciTech Connect

    Juneau, S.; Shirley, Y. L.; Bussmann, R. S.; Narayanan, D. T.; Moustakas, J.; Kennicutt, R. C.; Vanden Bout, P. A. E-mail: yshirley@as.arizona.ed E-mail: dnarayanan@cfa.harvard.ed E-mail: robk@ast.cam.ac.u

    2009-12-20

    We present a detailed analysis of the relation between infrared luminosity and molecular line luminosity, for a variety of molecular transitions, using a sample of 34 nearby galaxies spanning a broad range of infrared luminosities (10{sup 10} L{sub sun} < L{sub IR} < 10{sup 12.5} L{sub sun}). We show that the power-law index of the relation is sensitive to the critical density of the molecular gas tracer used, and that the dominant driver in observed molecular line ratios in galaxies is the gas density. As most nearby ultraluminous infrared galaxies (ULIRGs) exhibit strong signatures of active galactic nuclei (AGNs) in their center, we revisit previous claims questioning the reliability of HCN as a probe of the dense gas responsible for star formation in the presence of AGNs. We find that the enhanced HCN(1-0)/CO(1-0) luminosity ratio observed in ULIRGs can be successfully reproduced using numerical models with fixed chemical abundances and without AGN-induced chemistry effects. We extend this analysis to a total of 10 molecular line ratios by combining the following transitions: CO(1-0), HCO{sup +}(1-0), HCO{sup +}(3-2), HCN(1-0), and HCN(3-2). Our results suggest that AGNs reside in systems with higher dense gas fraction, and that chemistry or other effects associated with their hard radiation field may not dominate (NGC 1068 is one exception). Galaxy merger could be the underlying cause of increased dense gas fraction, and the evolutionary stage of such mergers may be another determinant of the HCN/CO luminosity ratio.

  1. 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

  2. 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.

  3. 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.

  4. Coaltar fractionation with a wide range of fractions. 3. Removal of high-boiling fractions from coaltar distillate

    SciTech Connect

    Gogoleva, T.Ya.; Krasulya, M.A.; Achkasova, G.G.; Butsinskaya, L.I.

    1992-12-31

    The high-boiling fractions of coaltar include the anthracene, phenanthrene-carbazole, fluoranthene, pyrene and chrysene cuts. At present, the anthracene fraction, containing 6.3-9.4% anthracene, is taken directly from the coaltar in single-column tube stills, whereas the phenanthrene-carbazole fractions are a by-product in the production of high-grade anthracene by the acetone process. Coke-oven plants in other countries do not recover the fluoranthene fraction from coaltar. There are known methods of recovering technical fluoranthene from the II-nd anthracene fraction or pitch distillates. The pyrene fraction is recovered from heavy pitch distillates containing up to 8% pyrene, or from a mixture of these distillates and pitch tar. The chrysene fraction, containing 9.8% chrysene, can be recovered from the pyrene fraction first taken from pitch distillates. However, there is no published information on the yields and qualities of the various high-boiling fractions obtainable from different feedstocks, and what few data there are relate to the 1960s-1970s. The purpose of this work was to recover narrow high-boiling cuts from the >290 {degrees}centigrade residue which was recovered from a coal tar distillate. 6 refs., 3 tabs.

  5. 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.

  6. 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

  7. 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

  8. Oxygen Isotopic Fractionation During Evaporation of SiO2 in Vacuum and in H Gas

    NASA Astrophysics Data System (ADS)

    Nagahara, H.; Young, E. D.; Hoering, T. C.; Mysen, B. O.

    1993-07-01

    Chondritic components, chondrules, CAIs, and some parts of the matrix are believed to have formed and/or thermally processed in the solar nebula. If this scenario is the case, they should be fractionated for major and minor elements and isotopes according to the formation temperature. This is true for major and trace elements, but is not the case for isotopes. Differences in oxygen isotopic composition among meteorite groups are interpreted to be the results of mixing of gas and dust from different oxygen reservoirs, and the effect of isotopic fractionation is negligible for most meteorites except for rare CAIs. Davis et al. [1] studied the isotopic fractionation of SiO2, MgO, and forsterite and showed that oxygen isotopic fractionation from solid materials is very small, but that from liquid is significant. Evaporation in the solar nebula should, however, be in hydrogen gas, which is reactive with silicates. Therefore, the effect of hydrogen gas on the evaporation behaviors of silicates, including mode of evaporation, evaporation rate, and compositional and isotopic fractionation, should be studied. Nagahara [2] studied the evaporation rate of SiO2 in equilibrium, in constant evacuation (free evaporation), and in hydrogen, and showed that the rate in hydrogen gas is orders of magnitude larger than that in vacuum; the mode of evaporation also differs from that in vacuum. Oxygen isotopic fractionation during evaporation of SiO2 in constant evacuation and in hydrogen gas at two different total pressures are studied in the present study. The starting material is a single crystal of natural quartz, which should transform into high cristobalite at experimental conditions. The powdered starting material was kept in a graphite capsule without a cap and set in a vacuum chamber with and without hydrogen gas flow. Experimental temperature was 1600 degrees C. Oxygen isotopic compositions (^18O/^16O) were measured with the CO2laser heating fluorination technique. Oxygen

  9. [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

  10. 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.

  11. 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.

  12. The regulation of the cold neutral gas mass fraction by turbulent motions

    NASA Astrophysics Data System (ADS)

    Gazol, A.; Villagran, M. A.

    2016-10-01

    We present results from hydrodynamic simulations with forced turbulence at a scale of 50 pc and cooling functions adapted to describe the thermal conditions at four different Galactocentric distances: 8.5, 11, 15, and 18 kpc. These experiments are aimed to study the effects of varying the turbulent velocity vrms on the cold gas mass fraction. With realistic vrms we obtain average one-dimensional cold gas mass fractions which are comparable with the observed values. Our simulations can also lead to an approximately constant cold gas mass fraction for distances ≥11 kpc when considering subsonic perturbations for 15 and 18 kpc. We also find that the average one dimensional cold gas mass fraction and the volumetric cold gas mass fraction do not follow the same radial trends.

  13. 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.

  14. 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.

  15. High pressure synthesis gas conversion

    SciTech Connect

    Not Available

    1992-01-01

    A high pressure gas phase fermentation system has been constructed for the biological production of ethanol from coal synthesis gas. The reactors in the system consist of a 650 mL continuous stirred tank reactor and a 1 L continuous column reactor. The reactors are designed for individual or dual operation in series or parallel, with continuous gas and liquid feed. The system is housed in a constant temperature, explosion-proof room, equipped with gas leak detectors.

  16. 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.

  17. Novel simulated moving-bed adsorber for the fractionation of gas mixtures.

    PubMed

    Rao, D P; Sivakumar, S V; Mandal, Susmita; Kota, Sridevi; Ramaprasad, B S G

    2005-03-25

    The separation of propylene-propane mixture is an energy intensive operation commercially practiced using cryogenic distillation. The separation by pressure swing adsorption has been studied as an alternative. A fixed-bed pressure swing adsorption yields the heavy component as a pure product. The product recovery and the productivity are not high. In a moving-bed process, because of the counter-current solid-gas contact, the separation achieved is similar to that of the fractionation by distillation. Although the moving-bed operation offers the upper limit for the performance of a cyclic adsorptive process, due to mechanical complexities in the handling of solids the 'simulated' moving-bed is preferred. By moving the inlet and outlet ports of streams located along the length of the bed, a moving-bed process can be realized in a fixed bed. We describe here a 'moving-port' system which permits injection or withdrawal of the fluid along the axial direction in a fixed bed. A fixed bed embedded with the moving-port systems emulates a simulated moving-bed adsorber. The proposed adsorber can fractionate a binary gas mixture into two product streams with high purities. It is similar to the Sorbex process of UOP but does not have the eluent as an additional separating agent. A parametric study indicates that high purity products and a higher productivity by an order of magnitude can be achieved with simulated moving-beds compared to the fixed beds.

  18. 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.

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

    NASA Astrophysics Data System (ADS)

    Nazari, Milad; Muddiman, David C.

    2016-08-01

    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.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. The X-ray/SZ view of the virial region. II. Gas mass fraction

    NASA Astrophysics Data System (ADS)

    Eckert, D.; Ettori, S.; Molendi, S.; Vazza, F.; Paltani, S.

    2013-03-01

    Aims: Several recent studies used the hot gas fraction of galaxy clusters as a standard ruler to constrain dark energy, which provides competitive results compared to other techniques. This method, however, relies on the assumption that the baryon fraction in clusters agrees with the cosmic value Ωb/Ωm, and does not differ from one system to another. We test this hypothesis by measuring the gas mass fraction over the entire cluster volume in a sample of local clusters. Methods: Combining the Sunyaev-Zel'dovich thermal pressure from Planck and the X-ray gas density from ROSAT, we measured for the first time the average gas fraction (fgas) out to the virial radius and beyond in a large sample of clusters. We also obtained azimuthally-averaged measurements of the gas fraction for 18 individual systems, which we used to compute the scatter of fgas around the mean value at different radii and its dependence on the cluster's temperature. Results: The gas mass fraction increases with radius and reaches the cosmic baryon fraction close to R200. At R200, we measure fgas,200 = 0.176 ± 0.009 (0.166 ± 0.012 for the subsample of 18 clusters in common between Planck and ROSAT). We find significant differences between the baryon fraction of relaxed, cool-core (CC) systems and unrelaxed, non-cool core (NCC) clusters in the outer regions. On average, the gas fraction in NCC clusters slightly exceeds the cosmic baryon fraction, while in CC systems the gas fraction converges to the expected value when accounting for the stellar content, without any evidence for variations from one system to another. Conclusions: We find that fgas estimates in NCC systems slightly disagree with the cosmic value approaching R200. This result could be explained either by a violation of the assumption of hydrostatic equilibrium or by an inhomogeneous distribution of the gas mass. Conversely, CC clusters are found to provide reliable constraints on fgas at overdensities Δ > 200, which makes them

  7. 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)

  8. 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.

  9. Can fractional quantum Hall effect be due to the formation of coherent wave structures in a 2D electron gas?

    NASA Astrophysics Data System (ADS)

    Mirza, Babur M.

    2016-05-01

    A microscopic theory of integer and fractional quantum Hall effects is presented here. In quantum density wave representation of charged particles, it is shown that, in a two-dimensional electron gas coherent structures form under the low temperature and high density conditions. With a sufficiently high applied magnetic field, the combined N particle quantum density wave exhibits collective periodic oscillations. As a result the corresponding quantum Hall voltage function shows a step-wise change in multiples of the ratio h/e2. At lower temperatures further subdivisions emerge in the Hall resistance, exhibiting the fractional quantum Hall effect.

  10. Spectroscopic method to measure the superfluid fraction of an ultracold atomic gas

    SciTech Connect

    John, S. T.; Hadzibabic, Z.; Cooper, N. R.

    2011-02-15

    We perform detailed analytical and numerical studies of a recently proposed method for a spectroscopic measurement of the superfluid fraction of an ultracold atomic gas [N. R. Cooper and Z. Hadzibabic, Phys. Rev. Lett. 104, 030401 (2010)]. Previous theoretical work is extended by explicitly including the effects of nonzero temperature and interactions, and assessing the quantitative accuracy of the proposed measurement for a one-component Bose gas. We show that for suitably chosen experimental parameters the method yields an experimentally detectable signal and a sufficiently accurate measurement. This is illustrated by explicitly considering two key examples: First, for a weakly interacting three-dimensional Bose gas it reproduces the expected result that below the critical temperature the superfluid fraction closely follows the condensate fraction. Second, it allows a clear quantitative differentiation of the superfluid and the condensate density in a strongly interacting Bose gas.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. The EMPIRE Survey: Systematic Variations in the Dense Gas Fraction and Star Formation Efficiency from Full-disk Mapping of M51

    NASA Astrophysics Data System (ADS)

    Bigiel, Frank; Leroy, Adam K.; Jiménez-Donaire, Maria J.; Pety, Jérôme; Usero, Antonio; Cormier, Diane; Bolatto, Alberto; Garcia-Burillo, Santiago; Colombo, Dario; González-García, Manuel; Hughes, Annie; Kepley, Amanda A.; Kramer, Carsten; Sandstrom, Karin; Schinnerer, Eva; Schruba, Andreas; Schuster, Karl; Tomicic, Neven; Zschaechner, Laura

    2016-05-01

    We present the first results from the EMPIRE survey, an IRAM large program that is mapping tracers of high-density molecular gas across the disks of nine nearby star-forming galaxies. Here, we present new maps of the 3 mm transitions of HCN, HCO+, and HNC across the whole disk of our pilot target, M51. As expected, dense gas correlates with tracers of recent star formation, filling the “luminosity gap” between Galactic cores and whole galaxies. In detail, we show that both the fraction of gas that is dense, {f}{dense} traced by HCN/CO, and the rate at which dense gas forms stars, {{SFE}}{dense} traced by IR/HCN, depend on environment in the galaxy. The sense of the dependence is that high-surface-density, high molecular gas fraction regions of the galaxy show high dense gas fractions and low dense gas star formation efficiencies. This agrees with recent results for individual pointings by Usero et al. but using unbiased whole-galaxy maps. It also agrees qualitatively with the behavior observed contrasting our own Solar Neighborhood with the central regions of the Milky Way. The sense of the trends can be explained if the dense gas fraction tracks interstellar pressure but star formation occurs only in regions of high density contrast.

  18. Effect of solvents on the fractionation of high oleic-high stearic sunflower oil.

    PubMed

    Bootello, Miguel A; Garcés, Rafael; Martínez-Force, Enrique; Salas, Joaquín J

    2015-04-01

    Solvent fractionation of high oleic-high stearic (HOHS) sunflower oil was studied to determine the best solvent to use (hexane or acetone) in terms of the operational parameters and properties of the final stearins. Acetone fractionation on two types of HOHS sunflower oils (N17 and N20) was carried out at temperatures from 5 to 10 °C using micelles with different oil/solvent ratios. Acetone was more suitable than hexane as a solvent for HSHO sunflower oil fractionation because it allowed the oil to be fractionated at higher temperatures and at lower supercooling degrees. Likewise, a sunflower soft stearin obtained by dry fractionation of HOHS sunflower oil was also used to produce high-melting point stearins by acetone or hexane fractionation. The fractionation of these stearins could be performed at higher temperatures and gave higher yields. The combination of dry and solvent fractionation to obtain tailor-made stearins is discussed.

  19. 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.

  20. Highly Siderophile Element Fractionation During Magma Transport in the Mantle

    NASA Astrophysics Data System (ADS)

    Becker, H.; van Acken, D.; Fischer-Goedde, M.

    2009-12-01

    Compared to mantle rocks, MORBs and many OIBs show very low, but fractionated PGE abundances (e. g., Hertogen et al., 1980; Rehkämper et al., 1999; Bezos et al. 2005). The basalt data have been explained by fractional crystallization of sulfides, olivine, and possibly alloy phases or chromite (e. g., Rehkämper et al., 1999; Mallmann and O’Neill, 2007). Where these fractionations occur, and what the actual HSE compositions of near-primary mantle melts are, remain open questions. Here we examine evidence for HSE fractionation during magma transport in the mantle. Strongly fractionated highly siderophile element patterns (HSE, the PGE, Re and Au) and relatively high Re abundances of mantle pyroxenites indicate close affinities of these rocks with basalts. This may come hardly as a surprise if pyroxenites represent high-pressure cumulates or melting residues of basic rocks. Sulphide compositions and subparallel HSE patterns of pyroxenite whole rocks suggest that their HSE abundances reflect variable precipitation of sulphides from silicate melt, and thus should be controlled by sulphide-silicate partitioning. Detailed work shows that absolute and relative HSE abundances in some pyroxenites vary with proximity of the peridotite wall rock. Major element, HSE and Os isotopic compositions of Cr diopside websterite and orthopyroxenite rocks suggest that these rocks crystallized from hybrid melts. Such melts likely were modified during reactive infiltration of peridotite, causing dissolution of olivine, Cr spinel and HSE bearing sulphides. Sulfides with melt like and peridotite like compositions in websterites may indicate that some peridotite derived sulphides may have never completely dissolved in these hybrid melts (van Acken et al., in press). Contamination with unradiogenic Os from peridotite results in dramatic shifts of the Os isotopic composition from highly radiogenic in unmodified melts to moderately suprachondritic in hybrid melts and their precipitates. Most

  1. Emittance and proton fraction measurement in High current electron cyclotron resonance proton ion source

    NASA Astrophysics Data System (ADS)

    Roychowdhury, P.; Kewlani, H.; Mishra, L.; Gharat, S.; Rajawat, R. K.

    2015-09-01

    The beam characterization studies in terms of emittance and proton fraction have been carried out in the high current Electron Cyclotron Resonance (ECR) proton ion source developed for Low Energy High Intensity Proton Accelerator (LEHIPA). The beam emittance was measured using two slit emittance measurement units (EMU). The emittance was measured at three locations (1) after beam extraction at ion source end, (2) after focusing the beam using solenoid magnet and (3) after focusing and separating H+ using solenoid magnet and analyzing magnet. The beam emittance measured in all three cases was found to be less than 0.2π mm-mrad (rms-normalized). The proton fraction in the beam measured using analyzing magnet was found to be more than 90%. The variations of beam emittance and proton fraction have been studied as a function of microwave power and neutral gas pressure.

  2. 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

  3. [Volume fraction of gas vesicle and floating characteristics of cyanobacteria in Taihu Lake under different pressures].

    PubMed

    Wang, Wei; Cong, Hai-Bing; Xu, Ya-Jun; Chen, Wen-Jing; Xu, Si-Tao; Wu, Jun; Jiang, Xin-Yue

    2014-08-01

    In order to ascertain the volumetric change of gas vesicles in cyanobacteria and the floating characteristics, capillary pressure method and image analysis method were used to study burst situation and remanent volume fraction of gas vesicles in cyanobacteria under different pressures. The reform situation after pressuring was also analyzed in this research. The results showed that the volume fraction of gas vesicles in Taihu Lake were 29.52%, 5.73%, 4.43%, 2.71%, 2.46%, 2.19% under 0 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa determined by the image analysis, and were 10.93%, 1.14%, 0.90%, 0.27%, 0.14%, 0.04% determined by the capillary pressure method; cyanobacteria sank due to the gas vesicles' bursting when the pressure was greater than 0.4 MPa. Gas vesicles and structure after pressure were reformed with the lapse of time, under 1 000 lx, 25 degrees C, after 8 h, 24 h, 48 h, the reformed gas vesicles accounted for 31.02%, 45.68%, 81.05% of total gas vesicles before pressuring. Image analysis method is more accurate in the determination for cyanobacteria gas vesicles' volume, while the volume is smaller measured by traditional capillary pressure method.

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

    NASA Astrophysics Data System (ADS)

    Kim, Yong-Hyun; Kim, Ki-Hyun

    2015-07-01

    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.

  5. 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

  6. 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.

  7. Sensor for measuring the atomic fraction in highly dissociated hydrogen

    SciTech Connect

    Gardner, W.L.

    1994-12-31

    Atomic hydrogen is a very important constituent for processes ranging from cleaning oxide from GaAs and annealing amorphous silicon to the deposition of diamond. Because the usual techniques for measuring atomic fraction are either expensive and cumbersome to use, or unsuitable for application to highly dissociated hydrogen, a specially designed sensor was developed. Sensor design is based on a diffusion tube with noncatalytic walls, having one end open to the atom source and a catalytic closure at the other end. The sensor is simple and inexpensive to fabricate, and determining atom density is straightforward. Sensor design also inhibits thermal runaway, which occurs when atom density is high enough to impart enough recombination energy to the non-catalytic surface to substantially raise its temperature. While recombination coefficients for such surfaces are very low near room temperature, they increase nearly exponentially with temperature unless actively cooled. With the use of a straightforward calibration scheme to determine the variation in species fraction along the diffusion tube, the atomic fraction at the tube opening is determined. Design strategy, implementation considerations, and calibration method are presented. In addition, data obtained from an atomic hydrogen source are compared to relevant published data.

  8. 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.

  9. 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.

  10. Isotopic fractionation of methane and ethane hydrates between gas and hydrate phases

    NASA Astrophysics Data System (ADS)

    Hachikubo, Akihiro; Kosaka, Tomoko; Kida, Masato; Krylov, Alexey; Sakagami, Hirotoshi; Minami, Hirotsugu; Takahashi, Nobuo; Shoji, Hitoshi

    2007-11-01

    Isotopic fractionation of carbon and hydrogen in methane and ethane during the formation of gas hydrates was investigated. The gas hydrate samples were experimentally prepared in a pressure cell and isotopic compositions of both residual and hydrate-bound gases were measured. δD of hydrate-bound molecules of methane and ethane hydrates was several per mil lower than that of residual gas molecules in the formation processes, while there was no difference in the case of δ 13C. These isotopic differences in δD are enough small for discussing the source types of hydrate-bound gases using the δ 13C-δD diagram of Whiticar et al. [1986]. These results may provide useful insight into the formation process of gas hydrates.

  11. Using Cluster Gas Fractions to Estimate Total BH Mechanical Feedback Energy

    NASA Astrophysics Data System (ADS)

    Mathews, Bill

    2011-08-01

    The total mechanical feedback energy received by clusters of mass 4-11 × 10^{14} M_{sun} exceeds 10^{63} ergs and mean feedback luminosity 10^{46} erg/s. This can be estimated by comparing gas density profiles in idealized adiabatic clusters evolved to zero redshift with entropy and gas fraction profiles in clusters of the same mass. Feedback energy, stored as potential energy in the cluster gas, can be estimated by comparing the PE within the same gas mass in adiabatic and observed atmospheres which have expanded considerably. The total feedback energy far exceeds energy gained by supernovae or lost by radiation. Less than 1% of the feedback energy is deposited within the cooling radius, but the time-averaged mass inflow from cooling is nicely offset by outflow due to feedback expansion.

  12. Gas entropy in a representative sample of nearby X-ray galaxy clusters (REXCESS): relationship to gas mass fraction

    NASA Astrophysics Data System (ADS)

    Pratt, G. W.; Arnaud, M.; Piffaretti, R.; Böhringer, H.; Ponman, T. J.; Croston, J. H.; Voit, G. M.; Borgani, S.; Bower, R. G.

    2010-02-01

    We examine the radial entropy distribution and its scaling using 31 nearby galaxy clusters from the representative XMM-Newton cluster structure survey (REXCESS), a sample in the temperature range 2-9 keV selected in X-ray luminosity only, with no bias toward any particular morphological type. The entropy profiles are robustly measured at least out to R1000 in all systems and out to R500 in thirteen systems. Compared to theoretical expectations from non-radiative cosmological simulations, the observed distributions show a radial and mass-dependent excess entropy, such that the excess is greater and extends to larger radii in lower mass systems. At R500, the mass dependence and entropy excess are both negligible within the large observational and theoretical uncertainties. Mirroring this behaviour, the scaling of gas entropy is shallower than self-similar in the inner regions, but steepens with radius, becoming consistent with self-similar at R500. There is a large dispersion in scaled entropy in the inner regions, apparently linked to the presence of cool cores and dynamical activity; at larger radii the dispersion decreases by approximately a factor of two to 30 per cent, and the dichotomy between subsamples disappears. There are two peaks in the distribution of both inner slope and, after parameterising the profiles with a power law plus constant model, in central entropy K0. However, we are unable to distinguish between a bimodal or a left-skewed distribution of K0 with the present data. The distribution of outer slopes is unimodal with a median value of 0.98, and there is a clear correlation of outer slope with temperature. Renormalising the dimensionless entropy profiles by the gas mass fraction profile fgas (gas mass fraction variations with radius and mass are the cause of the observed entropy structural and scaling properties. The results are consistent with the picture of a cluster

  13. Fractional Quantum Hall Effects in a Two-Dimensional Atomic Gas

    NASA Astrophysics Data System (ADS)

    Zhao, Jianshi; Jacome, Louis; Gemelke, Nathan

    2014-03-01

    Fractional Hall effects in two-dimensional electron gases have dramatically altered the way we look at ordering in quantum many body systems. Despite heroic advances since their discovery, many predictions regarding unique behavior have yet to be observed. We describe new efforts to produce similar effects in cold atomic Bose gases. Previous experiments have observed strong correlation in large ensembles of rapidly rotating few body samples consistent with a description using bosonic analogues of fractional hall states. We describe extensions of these experiments to observe individual systems in a quantum gas micropscope, introduce strong interactions through Feshbach resonance, and extend effects to larger numbers of atoms. The use of impurity atoms to probe fractional hall droplets will also be discussed, as will the extension of these effects to higher spin samples by using multiple internal states of Rubidium-87.

  14. 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.

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. Thermal and Electrical Conductivities of a Three-Dimensional Ideal Anyon Gas with Fractional Exclusion Statistics

    NASA Astrophysics Data System (ADS)

    Qin, Fang; Wen, Wen; Chen, Ji-Sheng

    2014-07-01

    The thermal and electrical transport properties of an ideal anyon gas within fractional exclusion statistics are studied. By solving the Boltzmann equation with the relaxation-time approximation, the analytical expressions for the thermal and electrical conductivities of a three-dimensional ideal anyon gas are given. The low-temperature expressions for the two conductivities are obtained by using the Sommerfeld expansion. It is found that the Wiedemann—Franz law should be modified by the higher-order temperature terms, which depend on the statistical parameter g for a charged anyon gas. Neglecting the higher-order terms of temperature, the Wiedemann—Franz law is respected, which gives the Lorenz number. The Lorenz number is a function of the statistical parameter g.

  20. 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.

  1. High-Resolution Fractionation of Signaling Endosomes Containing Different Receptors

    PubMed Central

    McCaffrey, Gretchen; Welker, Jonathan; Scott, Jessica; van Der Salm, Louise; Grimes, Mark L.

    2010-01-01

    Receptor endocytosis is regulated by ligand binding, and receptors may signal after endocytosis in signaling endosomes. We hypothesized that signaling endosomes containing different types of receptors may be distinct from one another and have different physical characteristics. To test this hypothesis, we developed a high-resolution organelle fractionation method based on mass and density, optimized to resolve endosomes from other organelles. Three different types of receptors undergoing ligand-induced endocytosis were localized predominately in endosomes that were resolved from one another using this method. Endosomes containing activated receptor tyrosine kinases (RTKs), TrkA and EGFR, were similar to one another. Endosomes containing p75NTR (in the tumor necrosis receptor superfamily) and PAC1 (a G-protein-coupled receptor) were distinct from each other and from RTK endosomes. Receptor-specific endosomes may direct the intracellular location and duration of signal transduction pathways to dictate response to signals and determine cell fate. PMID:19416476

  2. 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.

  3. Nonequilibrium and local detection of the normal fraction of a trapped two-dimensional Bose gas

    NASA Astrophysics Data System (ADS)

    Carusotto, Iacopo; Castin, Yvan

    2011-11-01

    We propose a method to measure the normal fraction of a two-dimensional Bose gas, a quantity that generally differs from the noncondensed fraction. The idea is based on applying a spatially oscillating artificial gauge field to the atoms. The response of the atoms to the gauge field can be read out either mechanically from the deposited energy into the cloud or optically from the macroscopic optical properties of the atomic gas. The local nature of the proposed scheme allows one to reconstruct the spatial profile of the superfluid component; furthermore, the proposed method does not require having established thermal equilibrium in the gas in the presence of the gauge field. The theoretical description of the system is based on a generalization of the Dum-Olshanii theory of artificial gauge fields to the interacting many-body context. The efficiency of the proposed measurement scheme is assessed by means of classical field numerical simulations. An explicit atomic level scheme minimizing disturbing effects such as spontaneous emission and light shifts is proposed for 87Rb atoms.

  4. 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).

  5. Momentum Distribution and Condensate Fraction of a Fermion Gas in the BCS-BEC Crossover

    SciTech Connect

    Astrakharchik, G.E.; Boronat, J.; Casulleras, J.; Giorgini, S.

    2005-12-02

    By using the diffusion Monte Carlo method we calculate the one- and two-body density matrix of an interacting Fermi gas at T=0 in the BCS to Bose-Einstein condensate (BEC) crossover. Results for the momentum distribution of the atoms, as obtained from the Fourier transform of the one-body density matrix, are reported as a function of the interaction strength. Off-diagonal long-range order in the system is investigated through the asymptotic behavior of the two-body density matrix. The condensate fraction of pairs is calculated in the unitary limit and on both sides of the BCS-BEC crossover.

  6. 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.

  7. 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.

  8. 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

  9. Noble gas adsorption with and without mechanical stress: Not Martian signatures but fractionated air

    NASA Astrophysics Data System (ADS)

    Schwenzer, Susanne P.; Herrmann, Siegfried; Ott, Ulrich

    2012-06-01

    Sample preparation, involving physical and chemical methods, is an unavoidable step in geochemical analysis. From a noble gas perspective, the two important effects are loss of sample gas and/or incorporation of air, which are significant sources of analytical artifacts. This article reports on the effects of sample exposure to laboratory air without mechanical influence and during sample grinding. The experiments include pure adsorption on terrestrial analog materials (gibbsite and olivine) and grinding of Martian meteorites. A consistent observation is the presence of an elementally fractionated air component in the samples studied. This is a critical form of terrestrial contamination in meteorites as it often mimics the heavy noble gas signatures of known extra-terrestrial end-members that are the basis of important conclusions about the origin and evolution of a meteorite. Although the effects of such contamination can be minimized by avoiding elaborate sample preparation protocols, caution should be exercised in interpreting the elemental ratios (Ar/Xe, Kr/Xe), especially in the low-temperature step extractions. The experiments can also be transferred to the investigation of Martian meteorites with long terrestrial residence times, and to Mars, where the Mars Science Laboratory mission will be able to measure noble gas signatures in the current atmosphere and in rocks and soils collected on the surface in Gale crater.

  10. 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}ȯ ; however, below this luminosity threshold, minor mergers and secular processes dominate. Additionally, galaxies do not reach {L}{IR}\\gt {10}12.0{L}ȯ 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).

  11. 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.

  12. 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.

  13. Transport simulations of the ignited ITER with high helium fraction

    NASA Astrophysics Data System (ADS)

    Becker, G.

    1994-04-01

    Computer simulations with special versions of the one dimensional BALDUR predictive transport code are carried out to investigate the particle confinement of helium and hydrogen, the energy confinement and the burn control in the high density scenario of the ITER (CDA) physics phase. The code uses empirical transport coefficients for ELMy H mode plasmas, an improved model of the scrape-off layer (SOL), an impurity radiation model for helium and iron, and fast burn control by neutral beam injection feedback. A self-sustained thermonuclear burn is achieved for hundreds of seconds. The necessary radiation corrected energy confinement time τE is found to be 4.2 s, which is attainable according to the ITER H mode scaling. In the ignited ITER, a significant dilution of the DT fuel by helium takes place. Steady state helium fractions of up to 8% are obtained, which are found to be compatible with self-sustained burn. The SOL model yields self-consistent electron densities and temperatures at the separatrix (ne = 5.8 × 1019 m-3, Te = 80 eV)

  14. SCALING AND MODELING STUDIES OF HIGH-BOOTSTRAP FRACTION TOKAMAKS

    SciTech Connect

    PERKINS,FW; CASPER,TA; POLITZER,PA

    2002-11-01

    OAK A271 SCALING AND MODELING STUDIES OF HIGH-BOOTSTRAP FRACTION TOKAMAKS. A theoretical framework is developed to generate tokamak equilibrium configurations for which, on one hand, the current results entirely from the bootstrap current source driven by the pressure gradient while, on the other hand, the pressure gradient is determined from the thermal conduction equation with a thermal diffusivity constructed to have properties observed in confinement experiments: gyroBohm confinement, gradients only with respect to the poloidal flux, global confinement depending only on plasma current and independent of toroidal field, a critical temperature gradient, and an overall confinement improvement with negative shear. The nondimensional method used yields eigenvalues composed of a collection of physics quantities, resulting in scaling relations among physics variables. It is found that the plasma temperature scales as T {proportional_to} P{sup 2/3}{var_epsilon}{sup -1/3}, while I{sub p} {proportional_to} n{sup 1/2}P{sup 1/3} a {var_epsilon}{sup 1/12}. The system has a solvability criterion which does not permit solutions when the confinement improves rapidly with increasing negative shear. A simplified 1-D model captures the essential physics of the coupling between bootstrap current generation and thermal conduction.

  15. 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

    2013-03-01

    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. PMID:23375830

  16. 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.

  17. Proteomic investigation of natural killer cell microsomes using gas-phase fractionation by mass spectrometry.

    PubMed

    Blonder, Josip; Rodriguez-Galan, Maria Cecilia; Lucas, David A; Young, Howard A; Issaq, Haleem J; Veenstra, Timothy D; Conrads, Thomas P

    2004-04-01

    We have explored the utility of gas-phase fractionation by mass spectrometry (MS) in the mass-to-charge (m/z) dimension (GPF(m/z)) for increasing the effective number of protein identifications in cases where sample quantity limits the use of multi-dimensional chromatographic fractionation. A peptide digestate from proteins isolated from the membrane fraction of natural killer (NK) cells was analyzed by microcapillary reversed-phase liquid chromatography coupled online to an ion-trap (IT) mass spectrometer. Performing GPF(m/z) using eight narrow precursor ion scan m/z ranges enabled the identification of 340 NK cell proteins from 12 microg of digestate, representing more than a fivefold increase in the number of proteins identified as compared to the same experiment employing a standard precursor ion survey scan m/z range (i.e., m/z 400-2000). The results show that GPF(m/z) represents an effective technique for increasing protein identifications in global proteomic investigations especially when sample quantity is limited.

  18. HPF HIGH PRESSURE FACILITY GAS ANALYSIS SYSTEM IN BASEMENT / HIGH TEMPERATURE GAS FACILITY IN THE E

    NASA Technical Reports Server (NTRS)

    1980-01-01

    HPF HIGH PRESSURE FACILITY GAS ANALYSIS SYSTEM IN BASEMENT / HIGH TEMPERATURE GAS FACILITY IN THE ENGINE RESEARCH BUILDING ERB TEST CELL CE-13 / AUTOMATIC SCAN VALUE SYSTEM ON THE SECOND FLOOR OF THE INSTRUMENT RESEARCH LABORATORY IRL

  19. High velocity gas in external galaxies

    NASA Technical Reports Server (NTRS)

    Kamphuis, J.; Vanderhulst, J. M.; Sancisi, R.

    1990-01-01

    Two nearby, nearly face-on spiral galaxies, M 101 and NGC 6946, observed in the HI with the Westerbork Synthesis Radio Telescope (WSRT) as part of a program to search for high velocity gas in other galaxies, are used to illustrate the range of properties of high velocity gas in other galaxies found thusfar.

  20. 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.

  1. 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.

  2. 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.

  3. Synthesis, fractionation, and thin film processing of nanoparticles using the tunable solvent properties of carbon dioxide gas expanded liquids

    NASA Astrophysics Data System (ADS)

    Anand, Madhu

    Nanoparticles have received significant attention because of their unusual characteristics including high surface area to volume ratios. Materials built from nanoparticles possess unique chemical, physical, mechanical and optical properties. Due to these properties, they hold potential in application areas such as catalysts, sensors, semiconductors and optics. At the same time, CO 2 in the form of supercritical fluid or CO2 gas-expanded liquid mixtures has gained significant attention in the area of processing nanostructures. This dissertation focuses on the synthesis and processing of nanoparticles using CO2 tunable solvent systems. Nanoparticle properties depend heavily on their size and, as such, the ability to finely control the size and uniformity of nanoparticles is of utmost importance. Solution based nanoparticle formation techniques are attractive due to their simplicity, but they often result in the synthesis of particles with a wide size range. To address this limitation, a post-synthesis technique has been developed in this dissertation to fractionate polydisperse nanoparticles ( s . = 30%) into monodisperse fractions ( s . = 8%) using tunable physicochemical properties of CO 2 expanded liquids, where CO2 is employed as an antisolvent. This work demonstrates that by controlling the addition of CO2 (pressurization) to an organic dispersion of nanoparticles, the ligand stabilized nanoparticles can be size selectively precipitated within a novel high pressure apparatus that confines the particle precipitation to a specified location on a surface. Unlike current techniques, this CO2 expanded liquid approach provides faster and more efficient particle size separation, reduction in organic solvent usage, and pressure tunable size selection in a single process. To improve our fundamental understanding and to further refine the size separation process, a detailed study has been performed to identify the key parameters enabling size separation of various

  4. 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. PMID:21482310

  5. 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.

  6. High-efficiency plasma display panel based on a high xenon mole fraction

    SciTech Connect

    Uhm, Han S.; Son, Chang G.; Hong, Byung H.; Choi, Eun H.

    2009-09-15

    The luminance efficiency of a plasma display panel is directly related to the vacuum-ultraviolet (VUV) light emitted from excited xenon atoms and molecules. The emission efficiency of 173 nm VUV light is measured in terms of the xenon mole fraction ({chi}) and is shown to become considerably enhanced at a high xenon mole fraction. For example, the emission efficiency at {chi}=0.35 under a pressure of 400 Torr is more than 2.5 times that at {chi}=0.1. The experimental data agree remarkably well with theoretical predictions.

  7. 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. PMID:17677233

  8. The separation process of methane-butane fraction from natural gas before transport

    NASA Astrophysics Data System (ADS)

    Galtseva, O. V.; Bordunov, S. V.

    2015-04-01

    A series of experiments of adsorption of vapor-air mixtures of some individual hydrocarbons on fibrous sorbents out of polyethylene and polypropylene is made. The calculated changes of concentrations of hydrocarbons in the vapor-air mixture base on experimental data. It is shown that concentration of hydrocarbons decreases after column by 1.4 times and that sorption capacity of fibers reaches 1 g of hydrocarbons on 1 g of a fibrous sorbent. This result was assumed as a basis of calculation of model of the separator for separation of hydrocarbons C1-4 from water and fractions C5-n, the degree of separation of the first stage gas of the Verkhne - Tarskoe's field was 98%.

  9. 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.

  10. Magnetic resonance imaging of velocity fields, the void fraction and gas dynamics in a cavitating liquid

    NASA Astrophysics Data System (ADS)

    Mastikhin, Igor V.; Arbabi, Aidin; Newling, Benedict; Hamza, Abdelhaq; Adair, Alexander

    2012-01-01

    In acoustic cavitation, the relationship between the bubble dynamics on the microscale and the flow properties on the macroscale is critical in determining sonochemical reaction kinetics. A new technique was developed to measure the void fraction and estimate water mobility in the vicinity of cavitating bubbles using phase-encoded magnetic resonance imaging with short characteristic measurement timescales (0.1-1 ms). The exponential behavior of the NMR signal decay indicated the fast diffusion regime, with the relationship between local mechanical dispersion D mix and the average bubble radius R, D_mix≫ 2R^2/10^{-4s}, resulting in dispersion of orders of magnitude greater than diffusion in quiescent water. For two different samples (water and a surfactant solution), the independent measurements of three-dimensional void fraction and velocity fields permitted the calculation of compressibility, divergence and vorticity of the cavitating medium. The measured dynamics of the dissolved gas, compared with that of the surrounding liquid, reflected the difference in the bubble coalescence and lifetimes and correlated with the macroscopic flow parameters.

  11. Second sound and the superfluid fraction in a Fermi gas with resonant interactions.

    PubMed

    Sidorenkov, Leonid A; Tey, Meng Khoon; Grimm, Rudolf; Hou, Yan-Hua; Pitaevskii, Lev; Stringari, Sandro

    2013-06-01

    Superfluidity is a macroscopic quantum phenomenon occurring in systems as diverse as liquid helium and neutron stars. It occurs below a critical temperature and leads to peculiar behaviour such as frictionless flow, the formation of quantized vortices and quenching of the moment of inertia. Ultracold atomic gases offer control of interactions and external confinement, providing unique opportunities to explore superfluid phenomena. Many such (finite-temperature) phenomena can be explained in terms of a two-fluid mixture comprising a normal component, which behaves like an ordinary fluid, and a superfluid component with zero viscosity and zero entropy. The two-component nature of a superfluid is manifest in 'second sound', an entropy wave in which the superfluid and the non-superfluid components oscillate with opposite phases (as opposed to ordinary 'first sound', where they oscillate in phase). Here we report the observation of second sound in an ultracold Fermi gas with resonant interactions. The speed of second sound depends explicitly on the value of the superfluid fraction, a quantity that is sensitive to the spectrum of elementary excitations. Our measurements allow us to extract the temperature dependence of the superfluid fraction, a previously inaccessible quantity that will provide a benchmark for theories of strongly interacting quantum gases. PMID:23676679

  12. 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. PMID:26906600

  13. 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.

  14. 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.

  15. 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

  16. 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

  17. 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

  18. 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.

  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. Thixoforming A356 Aluminum Bipolar Plates at High Solid Fractions

    NASA Astrophysics Data System (ADS)

    Bolouri, Amir; Jang, Chang Hyun; Kang, Chung Gil

    2014-04-01

    Thixoforming investigations have been developed primarily for the manufacturing of bulk components, and the current knowledge is very limited with respect to the fabrication of thin cross sections of alloys. We studied the effectiveness of thixoforming process for the fabrication of A356 aluminum alloy bipolar plates with microchannels on both sides. Feedstock semisolid slurries, with different solid contents of ~55, 50, and 45 pct, were prepared at 858 K, 863 K, and 868 K (585 °C, 590 °C, and 595 °C), respectively, and were used to thixoform 1.20-mm-thick bipolar thin plates. The microstructures of the thixoformed thin plates consisted of (i) large primary α-Al globular grains, (ii) a quenched liquid phase, and (iii) fine secondary α-Al particles. The fraction and size of the primary α-Al globular grains decreased, and the primary α-Al globular grains became more spherical with the increasing thixoforming temperature. It seemed that these changes in the microstructural features led to the reduction in the agglomeration and interaction among the primary α-Al globular grains surrounded by the liquid matrix during thixoforming. This enabled the semisolid slurry to effectively flow and fill in the sharp corners (such as the microchannels) of the die cavity at higher thixoforming temperatures. The thin plates thixoformed at 868 K (595 °C), consequently, exhibited the highest dimensional stability and the fewest internal defects. The liquid matrix surrounding the primary α-Al grains solidified inside the die cavity after thixoforming. Either the liquid phase was instantly quenched or fine secondary α-Al particles were formed inside the die cavity. The fraction and size of the latter increased with increasing thixoforming temperature. The surface hardness of the thixoformed plates was measured, and the hardness values were correlated with the microstructural features of the thixoformed plates.

  1. 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

  2. High Resolution Gamma Ray Tomography and its Application to the Measurement of Phase Fractions in Chemical Reactors

    NASA Astrophysics Data System (ADS)

    Hampel, Uwe; Bieberle, Andre; Schleicher, Eckhard; Hessel, Günther; Zippe, Cornelius; Friedrich, Hans-Jürgen

    2007-06-01

    We applied gamma ray tomography to the problem of phase fraction measurement in chemical reactors. Therefore, we used a new tomography device that is operated with a Cs-137 source and a high resolution gamma ray detector. One application example is the reconstruction of the fluid distribution and the measurement of radial gas fraction profiles in a laboratory scale stirred vessel. The tomograph was used to obtain radiographic projections of the averaged gamma ray attenuation for different stirrer speeds along the height of the vessel. With tomographic reconstruction techniques we calculated the angularly averaged radial distribution of the attenuation coefficient for as many as 150 single cross-sectional planes and synthesised from this data set the axial and radial fluid distribution pattern. Further, we exemplarily reconstructed the radial gas fraction distributions induced by the stirrer in the area of the stirrer blades. In a second application the gamma ray measurement system was used to visualise gas inclusions in a water cleaning column that is used to remove hazardous heavy metal species from water.

  3. 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.

  4. 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}.

  5. 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.

  6. 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

  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, 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.

  8. 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.

  9. 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.

  10. 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

  11. 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%.

  12. 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.

  13. 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

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

    NASA Astrophysics Data System (ADS)

    Yeliseyev, Yu. N.

    2010-07-01

    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

  15. Revolving fraction collector for preparative capillary gas chromatography in the 100-μg to 1-ng range.

    PubMed

    Wassgren, A B; Bergström, G

    1984-11-01

    A gas chromatography fraction collector for use with capillary columns, consisting of an all-glass system with a revolving collector housing six capillary tubes, 100 × 1 mm (internal diameter), has been constructed and tested. The collector is cooled with solid CO2 and has a recovering efficiency of 50-75% in the 100-μg to 1-ng range for compounds of different polarities and volatilities, exemplified by mono- and sesquiter-penes and long-chain esters. The technique has been used for fractionating blends of semiochemicals prior to microchemical reactions, spectroscopic analyses, and behavioral experiments. PMID:24318389

  16. Carbon in different phases ([CII], [CI], and CO) in infrared dark clouds: Cloud formation signatures and carbon gas fractions

    NASA Astrophysics Data System (ADS)

    Beuther, H.; Ragan, S. E.; Ossenkopf, V.; Glover, S.; Henning, Th.; Linz, H.; Nielbock, M.; Krause, O.; Stutzki, J.; Schilke, P.; Güsten, R.

    2014-11-01

    Context. How molecular clouds form out of the atomic phase and what the relative fractions of carbon are in the ionized, atomic, and molecular phase are questions at the heart of cloud and star formation. Aims: We want to understand the kinematic processes of gas flows during the formation of molecular clouds. In addition to that, we aim at determining the abundance ratios of carbon in its various gas phases from the ionized to the molecular form. Methods: Using multiple observatories from Herschel and SOFIA to APEX and the IRAM 30 m telescope, we mapped the ionized and atomic carbon as well as carbon monoxide ([CII] at 1900 GHz, [CI] at 492 GHz, and C18O(2-1) at 220 GHz) at high spatial resolution (12''-25'') in four young massive infrared dark clouds (IRDCs). Results: The three carbon phases were successfully mapped in all four regions, only in one source does the [CII] line remain a non-detection. With these data, we dissect the spatial and kinematic structure of the four IRDCs and determine the abundances of gas phase carbon in its ionized, atomic, and most abundant molecular form (CO). Both the molecular and atomic phases trace the dense structures well, with [CI] also tracing material at lower column densities. [CII] exhibits diverse morphologies in our sample from compact to diffuse structures, probing the cloud environment. In at least two out of the four regions, we find kinematic signatures strongly indicating that the dense gas filaments have formed out of a dynamically active and turbulent atomic and molecular cloud, potentially from converging gas flows. The atomic carbon-to-CO gas mass ratios are low between 7% and 12% with the lowest values found toward the most quiescent region. In the three regions where [CII] is detected, its mass is always higher by a factor of a few than that of the atomic carbon. While the ionized carbon emission depends on the radiation field, we also find additional signatures that indicate that other processes, for example

  17. 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.

  18. 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.

  19. 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.

  20. NSTX High Field Side Gas Fueling System

    SciTech Connect

    H.W. Kugel; M. Anderson; G. Barnes; M. Bell; W. Blanchard; L. Dudek; D. Gates; R. Gernhardt; R. Maingi; D. Mueller; T. Provost; R. Raman; V. Soukhanovskii; J. Winston

    2003-10-09

    Fueling National Spherical Torus Experiment (NSTX) plasmas with gas injected from the high field side (HFS) has produced earlier, more reliable transitions to the H-mode, longer H-mode durations, higher toroidal rotation, and higher edge electron temperature compared with similar discharges using the low field side (LFS) gas fueling injectors. The HFS gas fueling system consists of a Center Stack midplane injector, and an injector at the inner, upper corner of the Center Stack. The challenging design and installation constraints for the HFS gas system involved placing the control components as close as possible to the machine-vacuum interface, devising a special feed-through flange, traversing through vessel regions whose temperatures during bake-out range from 150 to 350 degrees Centigrade, adapting the gas transport tubing size and route to the small instrumentation wire channels behind the existing graphite plasma facing component tiles on the Center Stack, and providing output orifices shielded from excessive plasma power depositions while concentrating the output flow to facilitate fast camera viewing and analysis. Design, recent performance, and future upgrades will be presented.

  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. 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.}.

  3. 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.

  4. The effects of high dose and highly fractionated radiation on distraction osteogenesis in the murine mandible.

    PubMed

    Monson, Laura A; Cavaliere, Christi M; Deshpande, Sagar S; Ayzengart, Alexander L; Buchman, Steven R

    2012-09-07

    The ability of irradiated tissue to support bony growth remains poorly defined, although there are anecdotal cases reported showing mixed results for the use of mandibular distraction osteogenesis after radiation for head and neck cancer. Many of these reports lack objective measures that would allow adequate analysis of outcomes or efficacy. The purpose of this experiment was to utilize a rat model of mandibular distraction osteogenesis after high dose and highly fractionated radiation therapy and to evaluate and quantify distracted bone formation under these conditions. Male Sprague-Dawley rats underwent 12 fractions of external beam radiation (48 Gray) of the left mandible. Following a two week recovery period, an external frame distractor was applied and gradual distraction of the mandible was performed. Tissue was harvested after a twenty-eight day consolidation period. Gross, radiologic and histological evaluations were undertaken. Those animals subjected to pre-operative radiation showed severe attenuation of bone formation including bone atrophy, incomplete bridging of the distraction gap, and gross bony defects or non-union. Although physical lengthening was achieved, the irradiated bone consistently demonstrated marked damaging effects on the normal process of distraction osteogenesis. This murine model has provided reliable evidence of the injurious effects of high dose radiation on bone repair and regeneration in distraction osteogenesis utilizing accurate and reproducible metrics. These results can now be used to assist in the development of therapies directed at mitigating the adverse consequences of radiation on the regeneration of bone and to optimize distraction osteogenesis so it can be successfully applied to post-oncologic reconstruction.

  5. 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.

  6. 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

  7. 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.

  8. Simultaneous, noninvasive measurements of convective heat transfer and solid volume fraction at the wall of an entrained gas-solid suspension

    SciTech Connect

    Griffith, A. Elizabeth; Louge, Michel; Mohd-Yusof, Jamaludin

    2000-07-01

    We describe an instrument for local, instantaneous, noninvasive, simultaneous measurements of solid volume fraction and convective heat transfer at the wall of a vertical tube containing a relatively dense, entrained suspension of gas and fine solids. The instrument combines a small platinum coil and a guarded capacitance sensor. The capacitance sensor records instantaneous solid volume fraction in the near vicinity of the wall. The coil is maintained at constant temperature by a rapid anemometer bridge circuit. The vessel is wrapped in electric heaters to avoid artificially high rates associated with developing heat transfer and to minimize conduction losses from the coil. Using a model capturing these losses, convective heat transfer rates are inferred from the power input to the coil. The instrument is tested in a cold circulating fluidized bed riser. The temporal response of the thermal sensor is faster than 30 ms. (c) 2000 American Institute of Physics.

  9. Chemical characterization of high-molar-mass fractions in a Norway spruce knotwood ethanol extract.

    PubMed

    Smeds, Annika I; Eklund, Patrik C; Willför, Stefan M

    2016-10-01

    The low-molar-mass (LMM) fraction, only, i.e., the GC-eluting compounds, which are mainly lignans, has been characterized in Norway spruce knotwood hydrophilic extracts previously. Of this fraction, many lignans and sesquilignans and all GC peaks supposedly representing dilignans remain unidentified. In this work, dilignans and the GC non-eluting compounds (the high-molar mass fractions, HMM) were characterized in a 7-hydroxymatairesinol-reduced knotwood ethanol extract of Norway spruce by using several fractionation and analytical techniques. A methyl tert-butyl ether (MTBE) insoluble fraction of the extract contained mainly HMM material, of which the main part was shown to consist of lignan oligomers. The oligolignans (with a molar mass up to approximately 3700 Da) seemed to be linked by 55' bonds, some of them containing one or two guaiacylglycerol ether units linked to the lignan by βO4 or β5 bonds. Several oligolignans were identified or tentatively identified. The MTBE soluble fraction, which accounted for the major part (81%) of the extract, contained mainly LMM material (lignans, sesqui- and dilignans). The part of the HMM material in the MTBE soluble fraction that was easily isolable (2%) seemed to contain polymers of fatty acids and alcohols, resin acids, and sterols. PMID:27256310

  10. An Economical High-Throughput Protocol for Multidimensional Fractionation of Proteins

    PubMed Central

    Tooth, David John; Gopala Krishna, Varun; Layfield, Robert

    2012-01-01

    A sequential protocol of multidimensional fractionation was optimised to enable the comparative profiling of fractions of proteomes from cultured human cells. Differential detergent fractionation was employed as a first step to obtain fractions enriched for cytosolic, membrane/organelle, nuclear, and cytoskeletal proteins. Following buffer exchange using gel-permeation chromatography, cytosolic proteins were further fractionated by 2-dimensional chromatography employing anion-exchange followed by reversed-phase steps. Chromatographic fractions were shown to be readily compatible with 1- and 2-dimensional gel electrophoresis or with direct analysis by mass spectrometry using linear-MALDI-TOF-MS. Precision of extraction was confirmed by reproducible SDS-PAGE profiles, MALDI-TOF-MS spectra, and quantitation of trypsinolytic peptides using LC-MS/MS (MRM) analyses. Solid phases were immobilised in disposable cartridges and mobile-phase flow was achieved using a combination of centrifugation and vacuum pumping. These approaches yielded parallel sample handling which was limited only by the capacities of the employed devices and which enabled both high-throughput and experimentally precise procedures, as demonstrated by the processing of experimental replicates. Protocols were employed at 10 mg scale of extracted cell protein, but these approaches would be directly applicable to both smaller and larger quantities merely by adjusting the employed solid- and mobile-phase volumes. Additional potential applications of the fractionation protocol are briefly described. PMID:23008771

  11. Properties of high-oleic palm oils derived by fractional crystallization.

    PubMed

    Ramli, M R; Siew, W L; Cheah, K Y

    2008-04-01

    High-oleic palm oil (HOPO) with an oleic acid content of 59.0% and an iodine value (IV) of 78.2 was crystallized in a 200-kg De Smet crystallizer with a predetermined cooling program and appropriate agitation. The slurry was then fractionated by means of dry fractionation at 4, 8, 10, 12, and 15 degrees C. The oil and the fractionated products were subjected to physical and chemical analyses, including fatty acid composition, triacylglycerol and diacylglycerol composition, solid fat content, cloud point, slip melting point, and cold stability test. Fractionation at 15 degrees C resulted in the highest olein yield but with minimal oleic acid content. Due to the enhanced unsaturation of the oil, fractionation at relatively lower crystallization temperature showed a considerable effect on fatty acid composition as well as triacylglycerol and diacylglycerol composition of liquid fractions compared to higher crystallization temperature. The olein and stearin fractionated at 4 degrees C had the best cold stability at 0 degrees C and sharper melting profile, respectively.

  12. 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

  13. Metal and Metalloid Size-Fractionation Strategies in Spatial High-Resolution Sediment Pore Water Profiles.

    PubMed

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

    2016-09-01

    Sediment water interfaces (SWIs) are often characterized by steep biogeochemical gradients determining the fate of inorganic and organic substances. Important transport processes at the SWI are sedimentation and resuspension of particulate matter and fluxes of dissolved materials. A microprofiling and micro sampling system (missy), enabling high resolution measurements of sediment parameters in parallel to a direct sampling of sediment pore waters (SPWs), was combined with two fractionation approaches (ultrafiltration (UF) and cloud point extraction (CPE)) to differentiate between colloidal and dissolved fractions at a millimeter scale. An inductively coupled plasma-quadrupole mass spectrometry method established for volumes of 300 μL enabled the combination of the high resolution fractionation with multi-element analyzes. UF and CPE comparably indicated that manganese is predominantly present in dissolved fractions of SPW profiles. Differences found for cobalt and iron showed that the results obtained by size-dependent UF and micelle-mediated CPE do not necessarily coincide, probably due to different fractionation mechanisms. Both methods were identified as suitable for investigating fraction-related element concentrations in SPW along sediment depth profiles at a millimeter scale. The two approaches are discussed with regard to their advantages, limitations, potential sources of errors, further improvements, and potential future applications. PMID:27504804

  14. 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

  15. 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

  16. 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.

  17. 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.

  18. High-Resolution Simulations of Gas-Solids Jet Penetration Into a High Density Riser Flow

    SciTech Connect

    Li, Tingwen

    2011-05-01

    High-resolution simulations of a gas-solids jet in a 0.3 m diameter and 15.9 m tall circulating fluidized bed (CFB) riser were conducted with the open source software-MFIX. In the numerical simulations, both gas and solids injected through a 1.6 cm diameter radial-directed tube 4.3 m above the bottom distributor were tracked as tracers, which enable the analysis of the characteristics of a two-phase jet. Two jetting gas velocities of 16.6 and 37.2 m/s were studied with the other operating conditions fixed. Reasonable flow hydrodynamics with respect to overall pressure drop, voidage, and solids velocity distributions were predicted. Due to the different dynamic responses of gas and particles to the crossflow, a significant separation of gas and solids within the jet region was predicted for both cases. In addition, the jet characteristics based on tracer concentration and tracer mass fraction profiles at different downstream levels are discussed. Overall, the numerical predictions compare favorably to the experimental measurements made at NETL.

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

    PubMed

    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.

  20. High-Dose-Rate Brachytherapy Boost for Prostate Cancer: Comparison of Two Different Fractionation Schemes

    SciTech Connect

    Kaprealian, Tania; Weinberg, Vivian; Speight, Joycelyn L.; Gottschalk, Alexander R.; Roach, Mack; Shinohara, Katsuto; Hsu, I.-Chow

    2012-01-01

    Purpose: This is a retrospective study comparing our experience with high-dose-rate (HDR) brachytherapy boost for prostate cancer, using two different fractionation schemes, 600 cGy Multiplication-Sign 3 fractions (patient group 1) and 950 cGy Multiplication-Sign 2 fractions (patient group 2). Methods and Materials: A total of 165 patients were treated for prostate cancer using external beam radiation therapy up to a dose of 45 Gy, followed by an HDR brachytherapy prostate radiation boost. Between July 1997 and Nov 1999, 64 patients were treated with an HDR boost of 600 cGy Multiplication-Sign 3 fractions; and between June 2000 and Nov 2005, 101 patients were treated with an HDR boost of 950 cGy Multiplication-Sign 2 fractions. All but 9 patients had at least one of the following risk features: pretreatment prostate-specific antigen (PSA) level >10, a Gleason score {>=}7, and/or clinical stage T3 disease. Results: Median follow-up was 105 months for group 1 and 43 months for group 2. Patients in group 2 had a greater number of high-risk features than group 1 (p = 0.02). Adjusted for comparable follow-up, there was no difference in biochemical no-evidence-of-disease (bNED) rate between the two fractionation scheme approaches, with 5-year Kaplan-Meier estimates of 93.5% in group 1 and 87.3% in group 2 (p = 0.19). The 5-year estimates of progression-free survival were 86% for group 1 and 83% for group 2 (p = 0.53). Among high-risk patients, there were no differences in bNED or PFS rate due to fractionation. Conclusions: Results were excellent for both groups. Adjusted for comparable follow-up, no differences were found between groups.

  1. Temperature-dependent isotopic fractionation of lithium between clinopyroxene and high-pressure hydrous fluids

    NASA Astrophysics Data System (ADS)

    Wunder, Bernd; Meixner, Anette; Romer, Rolf L.; Heinrich, Wilhelm

    2006-01-01

    The fractionation of lithium isotopes between synthetic spodumene as representative of Li-bearing clinopyroxene and Cl- and OH-bearing aqueous fluids was experimentally determined between 500 and 900°C at 2.0 GPa. In all the experiments, 7Li was preferentially partitioned into the fluid. The fractionation is temperature dependent and approximated by the equation Δ7Li(clinopyroxene-fluid)=-4.61×(1,000/ T [K]) + 2.48; R 2=0.86. Significant Li isotopic fractionation of about 1.0‰ exists even at high temperatures of 900°C. Using neutral and weakly basic fluids revealed that the amount of fractionation is not different. The Li isotopic fractionation between altered basalt and hot spring water (350°C) in natural samples is in good agreement with our experimentally determined fractionation curve. The data confirm earlier speculations drawn from the Li isotopic record of dehydrated metamorphic rocks that fluids expelled from a dehydrating slab carry heavier Li into the mantle wedge, and that a light Li component is introduced into the deeper mantle. Li and Li isotopes are redistributed among wedge minerals as fluids travel across the wedge into hotter regions of arc magma production. This modifies the Li isotopic characteristics of slab-derived fluids erasing their source memory, and explains the absence of cross-arc variations of Li isotopes in arc basalts.

  2. 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.

  3. 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.

  4. High speed exhaust gas recirculation valve

    DOEpatents

    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.

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Distinct effects of boar seminal plasma fractions exhibiting different protein profiles on the functionality of highly diluted boar spermatozoa.

    PubMed

    García, E M; Calvete, J J; Sanz, L; Roca, J; Martínez, E A; Vázquez, J M

    2009-04-01

    The aim of this study was to evaluate how different protein profiles of seminal plasma (SP) fractions affect sperm functionality in vitro. Ejaculates from three boars were separated into six fractions. The fractions differed from each other in their sperm content, in their total SP protein content, and their spermadhesin PSP-I/PSP-II and heparin-binding protein (HBP) concentrations. Spermatozoa were mainly recovered in fraction 2 (sperm-rich fraction, >1800 x 10(6) spermatozoa/ml), whereas the pre-sperm fraction 1 and the post-sperm fractions 4-6 contained low numbers of spermatozoa (<500 x 10(6)/ml). Except in fraction 2, the total SP protein concentration and the concentration of both, spermadhesin PSP-I/PSP-II and the HBPs increased with fraction order. Distinct time-dependent effects were observed on motility characteristics and membrane integrity of highly diluted boar spermatozoa upon incubation with a 10% dilution of the SP from each fraction. The highest sperm viability was recorded after exposure for 5 h to fraction 2, followed by fractions 1 and 3. The percentages of motile spermatozoa also differed significantly among fractions after 5 h of incubation. Spermatozoa incubated with SP of fractions 1-3 showed the highest percentage motility. We conclude that different SP fractions exert distinct effects on the functionality of highly diluted boar spermatozoa. Fractions 1-3 appear to promote sperm survival, whereas fractions 4-6 seem to be harmful for preserving the physiological functions of highly diluted boar spermatozoa. PMID:19323794

  13. Fractionation of technical octabromodiphenyl ether by countercurrent chromatography combined with gas chromatography/mass spectrometry and offline and online (1)H nuclear magnetic resonance spectroscopy.

    PubMed

    Hammann, Simon; Conrad, Jürgen; Vetter, Walter

    2015-06-12

    Countercurrent chromatography (CCC) is a technique, which uses two immiscible liquid phases for a separation process in a long and hollow tube. The technique allows the separation of high amounts of sample (50mg to several grams) with a low consumption of solvents. In this study, we fractionated 50mg technical octabromodiphenyl ether (DE-79) and analyzed the fractions by gas chromatography with mass spectrometry (GC/MS) and proton nuclear magnetic resonance ((1)H NMR) spectroscopy. CCC separations were performed with n-hexane/acetonitrile as solvent system in tail-to-head (i.e. the upper phase is mobile) mode. Twelve CCC fractions were studied for the PBDE composition. CCC elution of PBDE congeners was dependent both on the degree of bromination and substitution pattern. Higher brominated congeners eluted faster than lower brominated congeners and isomers with vicinal hydrogen atoms eluted last. In addition to several known PBDE congeners in DE-79, we were able to unequivocally identify BDE 195 in DE-79 and we could verify the presence of BDE 184. Finally, we also established the online hyphenation of CCC with (1)H NMR. The use of deuterated solvents could be avoided by using n-hexane/acetonitrile as two-phase system. By online CCC-(1)H NMR in stop-flow mode we were able to detect eight PBDE congeners in the mixture. PMID:25913330

  14. 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.

  15. 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.

  16. Nearby Clumpy, Gas Rich, Star-forming Galaxies: Local Analogs of High-redshift Clumpy Galaxies

    NASA Astrophysics Data System (ADS)

    Garland, C. A.; Pisano, D. J.; Mac Low, M.-M.; Kreckel, K.; Rabidoux, K.; Guzmán, R.

    2015-07-01

    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.

  17. 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.

  18. 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.

  19. Quantitative evaluation of carbon isotopic fractionation during reversed-phase high-performance liquid chromatography.

    PubMed

    Caimi, R J; Brenna, J T

    1997-01-01

    The fractionation of 13C during low-performance preparative LC and high-performance LC is reported quantitatively for methyl palmitate and using high-precision isotope ratio mass spectrometry (IR-MS). For both preparative and high-performance analytical columns, 13C enrichment is about 7% greater than the parent starting material, drops sharply in the first section of the peak and then settles to a value about 1% below that of the starting material. Recycling over a single HPLC column did not induce greater fractionation. These results emphasize the importance of quantitative peak collection for high-precision IR-MS studies, particularly the first part of the peak where the isotope ratio changes rapidly. PMID:9025266

  20. Production of high-brightness CW proton beams with very high proton fractions

    SciTech Connect

    Spence, D.; McMichael, G.; Lykke, K.R.; Schneider, J.D.; Sherman, J.; Stevens, R. Jr.; Hodgkins, D.

    1995-12-01

    This paper demonstrates a new technique to significantly enhance the proton fraction of an ion beam extracted from a plasma ion source. We employ a magnetically confined microwave driven source, though the technique is not source-specific and can probably be applied equally effectively to other plasma sources such as Penning and multicusp types. Specifically, we dope the plasma with about 1% H{sub 2}O, which increases the proton fraction of a 45 keV 45 mA beam from 75 to 90% with 375W 2.45 GHz power to the source and from 84% to 92% for 500W when the source is operated under nonresonant conditions. Much of the remaining fraction of the beam comprises a heavy mass ion we believe to be N{sup +} impurity ions resulting from the conditions under which the experiments were performed. If so, this impurity can be easily removed and much higher proton fractions could be expected. Preliminary measurements show the additive has no adverse effect on the emittance of the extracted beam, and source stability is greatly improved.

  1. Bimodular high temperature planar oxygen gas sensor.

    PubMed

    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

  2. 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

  3. 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.

  4. A comparative analysis of radiobiological models for cell surviving fractions at high doses.

    PubMed

    Andisheh, B; Edgren, M; Belkić, Dž; Mavroidis, P; Brahme, A; Lind, B K

    2013-04-01

    For many years the linear-quadratic (LQ) model has been widely used to describe the effects of total dose and dose per fraction at low-to-intermediate doses in conventional fractionated radiotherapy. Recent advances in stereotactic radiosurgery (SRS) and stereotactic radiotherapy (SRT) have increased the interest in finding a reliable cell survival model, which will be accurate at high doses, as well. Different models have been proposed for improving descriptions of high dose survival responses, such as the Universal Survival Curve (USC), the Kavanagh-Newman (KN) and several generalizations of the LQ model, e.g. the Linear-Quadratic-Linear (LQL) model and the Pade Linear Quadratic (PLQ) model. The purpose of the present study is to compare a number of models in order to find the best option(s) which could successfully be used as a fractionation correction method in SRT. In this work, six independent experimental data sets were used: CHOAA8 (Chinese hamster fibroblast), H460 (non-small cell lung cancer, NSLC), NCI-H841 (small cell lung cancer, SCLC), CP3 and DU145 (human prostate carcinoma cell lines) and U1690 (SCLC). By detailed comparisons with these measurements, the performance of nine different radiobiological models was examined for the entire dose range, including high doses beyond the shoulder of the survival curves. Using the computed and measured cell surviving fractions, comparison of the goodness-of-fit for all the models was performed by means of the reduced χ (2)-test with a 95% confidence interval. The obtained results indicate that models with dose-independent final slopes and extrapolation numbers generally represent better choices for SRT. This is especially important at high doses where the final slope and extrapolation numbers are presently found to play a major role. The PLQ, USC and LQL models have the least number of shortcomings at all doses. The extrapolation numbers and final slopes of these models do not depend on dose. Their asymptotes

  5. 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.

  6. 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

  7. Mercury fractionation, bioavailability, and ecotoxicity in highly contaminated soils from chlor-alkali plants.

    PubMed

    Zagury, Gerald J; Neculita, Carmen-Mihaela; Bastien, Christian; Deschênes, Louise

    2006-04-01

    Mercury (Hg) fractionation, speciation, bioavailability, and ecotoxicity were investigated in three highly contaminated soils from chlor-alkali plants. Single extractions and a validated four-step sequential extraction scheme were used. Total, volatile, and methyl-Hg concentrations were determined. Mercury was then separated in fractions defined as water-soluble (F1), exchangeable (F2), organic (F3), and residual (F4). Germination and growth inhibition of barley (Hordeum vulgare) and mortality of earthworms (Eisenia andrei) were assessed, and tissue-Hg concentrations of exposed organisms were determined. Results revealed highly (295 +/- 18-11,500 +/- 500 microg Hg/g) contaminated soils, but extracted fractions indicated relatively low mobility of Hg. Nevertheless, the water-soluble and the CaCl2-extractable fractions represented significant Hg concentrations (299 +/- 18 microg/g in soil 3, 67.4 +/- 2.3 microg/g in soil 1, and 9.5 +/- 0.3 microg/g in soil 2), and volatile Hg ranged between 14 and 98% of total Hg. Overall, Hg concentrations reached 6,560 +/- 240 microg/g in roots, 4,200 +/- 1,070 microg/g in aerial plants, and 1,410 +/- 120 microg/g in E. andrei. Earthworm mortality was 100% after exposure to the soil with the highest concentration of mobile Hg. In the latter soil, earthworm fragmentation and chlorotic plants were observed. Bioconcentration factors (BCFs) were higher in barley compared to earthworms, but BCFs yielded misleading values after exposure to the extremely contaminated soil. This study shows that Hg accumulated primarily in the roots, but results also indicate uptake of gaseous Hg by the aerial plants of barley. Tissue-Hg concentrations of both exposed organisms were correlated with water-soluble and CaCl2-extractable Hg, and growth inhibition was in agreement with Hg fractionation.

  8. On the molecular structure of the amylopectin fraction isolated from "high-amylose" ae maize starches.

    PubMed

    Peymanpour, Ghazal; Marcone, Massimo; Ragaee, Sanaa; Tetlow, Ian; Lane, Christopher C; Seetharaman, Koushik; Bertoft, Eric

    2016-10-01

    The amylopectin fractions from starch of a series of amylose-extender (ae) maize samples (HYLON(®) V, VII and VIII starches) were isolated and analysed for their molecular composition and structure. The fractions from all samples contained both a high and a low molecular weight fraction (HMF and LMF), of which LMF increased with the amylose content of the starch and appeared to have substantially more of long chains than HMF. A normal amylose-containing maize starch (NMS), which served as a reference sample, contained very little LMF, which suggested that LMF was the inherent result of the effect of the loss of starch branching enzyme IIb activity in the ae mutants. Clusters were isolated from the amylopectin fractions using Bacillus amyloliquefaciens α-amylase, which effectively hydrolyses long internal chain segments between clusters. During the hydrolysis process, clearly more of small dextrins were released from the ae starches in comparison to NMS. It appeared that some of these small dextrins did not precipitate in methanol together with the majority of the clusters. Nevertheless, isolated clusters from the HYLON starch samples were smaller than in NMS and the clusters possessed a lower density of branches with longer chains. The composition of small, branched building blocks was also clearly different: HYLON starch samples possessed much more of single-branched blocks and less multiple-branched blocks than NMS. PMID:27296443

  9. Point defect survival and clustering fractions obtained from molecular dynamics simulations of high energy cascades

    SciTech Connect

    Stoller, R.E.

    1995-12-31

    Evolution of high-energy displacement cascades in iron has been investigated for times up to 200 ps using molecular dynamics simulation. The simulations were carried out using the MOLDY code and a modified version of the many-body interatomic potential developed by Finnis and Sinclair. Previously reported results have been supplemented by a series of 10 keV simulations at 900 K and 20 keV simulations at 100K. Results indicate that the fraction of the Frenkel pairs escaping in-cascade recombination is somewhat higher and the fraction of the surviving point defects that cluster is lower in iron than in materials such as copper. In particular, vacancy clustering appears to be inhibited in iron. Many of the larger interstitial clusters were observed to exhibit a complex, three-dimensional morphology. Apparent mobility of the <111> crowdion and clusters of <111> crowdions was very high.

  10. Vector wave analysis of an electromagnetic high-order Bessel vortex beam of fractional type α.

    PubMed

    Mitri, F G

    2011-03-01

    The scalar wave theory of nondiffracting electromagnetic (EM) high-order Bessel vortex beams of fractional type α has been recently explored, and their novel features and promising applications have been revealed. However, complete characterization of the properties for this new type of beam requires a vector analysis to determine the fields' components in space because scalar wave theory is inadequate to describe such beams, especially when the central spot is comparable to the wavelength (k(r)/k≈1, where k(r) is the radial component of the wavenumber k). Stemming from Maxwell's vector equations and the Lorenz gauge condition, a full vector wave analysis for the electric and magnetic fields is presented. The results are of particular importance in the study of EM wave scattering of a high-order Bessel vortex beam of fractional type α by particles.

  11. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2010-06-01

    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.

  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. Two New FRET Imaging Measures: Linearly Proportional to and Highly Contrasting the Fraction of Active Molecules

    PubMed Central

    Yamao, Masataka; Aoki, Kazuhiro; Yukinawa, Naoto; Ishii, Shin; Matsuda, Michiyuki; Naoki, Honda

    2016-01-01

    We developed two new FRET imaging measures for intramolecular FRET biosensors, called linearly proportional (LP) and highly contrasting (HC) measures, which can be easily calculated by the fluorescence intensities of donor and acceptor as a ratio between their weighted sums. As an alternative to the conventional ratiometric measure, which non-linearly depends on the fraction of active molecule, we first developed the LP measure, which is linearly proportional to the fraction of active molecules. The LP measure inherently unmixes bleed-through signals and is robust against fluorescence noise. By extending the LP measure, we furthermore designed the HC measure, which provides highly contrasting images of the molecular activity, more than the ratiometric measure. In addition to their advantages, these measures are insensitive to the biosensor expression level, which is a fundamental property of the ratiometric measure. Using artificial data and FRET imaging data, we showed that the LP measure effectively represents the fraction of active molecules and that the HC measure improves visual interpretability by providing high contrast images of molecular activity. Therefore, the LP and HC measures allow us to gain more quantitative and qualitative insights from FRET imaging than the ratiometric measure. PMID:27780260

  15. High pressure synthesis gas conversion. Task 1, System construction

    SciTech Connect

    Not Available

    1992-01-01

    A high pressure gas phase fermentation system has been constructed for the biological production of ethanol from coal synthesis gas. The reactors in the system consist of a 650 mL continuous stirred tank reactor and a 1 L continuous column reactor. The reactors are designed for individual or dual operation in series or parallel, with continuous gas and liquid feed. The system is housed in a constant temperature, explosion-proof room, equipped with gas leak detectors.

  16. 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

  17. 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.

  18. Lyalpha RADIATIVE TRANSFER WITH DUST: ESCAPE FRACTIONS FROM SIMULATED HIGH-REDSHIFT GALAXIES

    SciTech Connect

    Laursen, Peter; Sommer-Larsen, Jesper; Andersen, Anja C. E-mail: jslarsen@astro.ku.d

    2009-10-20

    The Lyalpha emission line is an essential diagnostic tool for probing galaxy formation and evolution. Not only is it commonly the strongest observable line from high-redshift galaxies, but from its shape detailed information about its host galaxy can be revealed. However, due to the scattering nature of Lyalpha photons increasing their path length in a nontrivial way, if dust is present in the galaxy, the line may be severely suppressed and its shape altered. In order to interpret observations correctly, it is thus of crucial significance to know how much of the emitted light actually escapes the galaxy. In the present work, using a combination of high-resolution cosmological hydrosimulations and an adaptively refinable Monte Carlo Lyalpha radiative transfer code including an environment dependent model of dust, the escape fractions f {sub esc} of Lyalpha radiation from high-redshift (z = 3.6) galaxies are calculated. In addition to the average escape fraction, the variation of f {sub esc} in different directions and from different parts of the galaxies is investigated, as well as the effect on the emergent spectrum. Escape fractions from a sample of simulated galaxies of representative physical properties are found to decrease for increasing galaxy virial mass M {sub vir}, from f {sub esc} approaching unity for M {sub vir} approx 10{sup 9} M {sub sun} to f {sub esc} less than 10% for M {sub vir} approx 10{sup 12} M {sub sun}. In spite of dust being almost gray, it is found that the emergent spectrum is affected nonuniformly, with the escape fraction of photons close to the line center being much higher than of those in the wings, thus effectively narrowing the Lyalpha line.

  19. 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.

  20. 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

  1. 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'.

  2. 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'. PMID:27185959

  3. Cadmium isotope fractionation during adsorption to Mn oxyhydroxide at low and high ionic strength

    NASA Astrophysics Data System (ADS)

    Wasylenki, Laura E.; Swihart, Jared W.; Romaniello, Stephen J.

    2014-09-01

    We report results of experiments conducted to quantify the sense and magnitude of cadmium stable isotope fractionation during sorption to synthetic birnessite (Mn oxyhydroxide) and to constrain the molecular mechanism responsible for fractionation in this system. Ferromanganese crusts have recently been proposed as a possible archive of the cadmium isotopic composition of seawater over the last few tens of millions of years (Horner et al., 2010), and this archive can potentially yield information about biological use of Cd by diatoms over the Cenozoic Era. Cd isotopes may also be useful for determining the extent to which sorption to mineral substrates attenuates Cd transport in contaminated aquifers. At low ionic strength, we found a small fractionation effect (Δ114/112Cdfluid-solid = +0.12 ± 0.06‰, 1 sd; equivalent to +2.4 in terms of ε114/110Cd) that was constant as a function of the fraction of total Cd sorbed, indicating a reversible equilibrium isotope effect. At high ionic strength we observed a fractionation averaging (Δ114/112Cdfluid-solid = +0.27 ± 0.07‰ (1 sd; equivalent to +5.4 in terms of ε114/110Cd). A time series conducted at high ionic strength revealed that the magnitude of isotopic fractionation decreases gradually over time, from Δ114/112Cdfluid-solid of nearly +0.4‰ after 1 h to +0.2‰ after 24 h and +0.1‰ after 912 h. Furthermore, the percentage of Cd sorbed to birnessite increases over this interval from 27% to 58%. We hypothesize that this shift results from either changes over time in the structure and crystallinity of birnessite and/or a change in the molecular mechanism of sorption of cadmium on birnessite. Our result is encouraging for application of Cd isotopes in ferromanganese crusts to reconstruction of the Cd isotopic composition of coexisting seawater, given the very slow accumulation rates of such sediments.

  4. 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

  5. Two-dimensional late-stage coarsening for nucleation and growth at high-area fractions

    SciTech Connect

    Akaiwa, N.; Meiron, D.I.

    1996-07-01

    Numerical simulations of two-dimensional late-stage coarsening for nucleation and growth (Ostwald ripening) are performed at large-area fractions without shape restrictions. We employ efficient computational methods that allow us to study large systems. The free energy of the system we consider is composed of two different curves. Thus, the system consists of a set of isolated particles even at high-area fractions. This is totally different from the interconnected spinodal structures generated by the Cahn-Hilliard model, where the free energy is composed of a single curve. Although the domain structures are quite different, we find that the qualitative features of the structure function for both models are the same. {copyright} {ital 1996 The American Physical Society.}

  6. Damping behavior of polymer composites with high volume fraction of NiMnGa powders

    NASA Astrophysics Data System (ADS)

    Sun, Xiaogang; Song, Jie; Jiang, Hong; Zhang, Xiaoning; Xie, Chaoying

    2011-03-01

    Polymer composites inserted with high volume fraction (up to 70 Vol%) of NiMnGa powders were fabricated and their damping behavior was investigated by dynamic mechanical analysis. It is found that the polymer matrix has little influence on the transformation temperatures of NiMnGa powders. A damping peak appears for NiMnGa/epoxy resin (EP) composites accompanying with the martensitic transformation or reverse martensitic transformation of NiMnGa powders during cooling or heating. The damping capacity for NiMnGa/EP composites increases linearly with the increase of volume fraction of NiMnGa powders and, decreases dramatically as the test frequency increases. The fracture strain of NiMnGa/EP composites decrease with the increase of NiMnGa powders.

  7. 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. PMID:27446811

  8. 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.

  9. 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.

  10. Analysis of a mixture of polychlorinated biphenyls and chlorinated pesticides in human serum by column fractionation and dual-column capillary gas chromatography with electron capture detection.

    PubMed

    Najam, A R; Korver, M P; Williams, C C; Burse, V W; Needham, L L

    1999-01-01

    An analytical method is presented for precise identification and quantitation of 29 specific polychlorinated biphenyl (PCB) congeners and 15 chlorinated pesticides in human serum. Analyte surrogates PCB 30, PCB 204, 2,2',4,4',5,5'-hexabromo-biphenyl, perthane, alpha-hexachlorocyclohexane, and dichlorobenzophenone were added to each sample. The serum was extracted with an organic solvent and separated by adsorption chromatography into 3 elution fractions for high-resolution gas chromatographic analysis. Each fraction was analyzed by dual-column capillary chromatography followed by electron capture detection. Two capillary columns, DB-5 and DB-1701, with different polarities were used to increase selectivity for each analyte. Quantitation was performed by selecting 2 sets of calibration standard mixtures and 1,2-dichloronaphthalene as an internal standard. Mean recoveries ranged from 39 to 126% for selected analytes and from 31 to 88% for surrogates. Detection limits for specific congeners and pesticides are reported. Typical chromatographic profiles of calibration standard mixtures, as well as a human sample, are illustrated. Verification of each analyte is assessed, and results of analyses of selected human samples and quality control criteria used to ensure data validity also are presented.

  11. 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.

  12. Fractionated total lymphoid irradiation as preparative immunosuppression in high risk renal transplantation

    SciTech Connect

    Najarian, J.S.; Ferguson, R.M.; Sutherland, D.E.; Slavin, S.; Kim, T.; Kersey, J.; Simmons, R.L.

    1982-10-01

    Twenty-two patients at high risk to reject renal allografts have been treated with fractionated total lymphoid irradiation (FTLI) prior to transplantation of primary (2), secondary (16) or tertiary (4) renal allografts. All patients undergoing retransplantation had rapidly rejected previous grafts. At 24 months following transplantation, 72% of grafts were functioning in the TLI group compared with a 38% graft function in an historical control group of recipients receiving secondary or tertiary grafts and treated with conventional immunosuppression. Important variables in determining success of transplantation following fractionated TLI include the dose of TLI, the interval from radiation to transplantation, and maintenance post-transplant immunosuppressive therapy. Optimal results were achieved with 2500 rads delivered in 100 rad fractions followed by transplantation within two weeks, and a tapering prednisone schedule and maintenance azathioprine post-transplantation. Seventeen patients had significant complications of the radiation treatment and there was one death, prior to transplantation, associated with pneumonitis. In vitro assessment of immune function demonstrated marked peripheral T cell depletion and loss of in vitro responsiveness to mitogen and allogeneic stimulation following FTLI. The administration of donor bone marrow at the time of transplantation did not produce chimerism. The results suggest that when properly utilized FTLI can produce effective adjunctive immunosuppression for clinical transplantation.

  13. Fractionated total lymphoid irradiation as preparative immunosuppression in high risk renal transplantation: clinical and immunological studies

    SciTech Connect

    Najarian, J.S.; Ferguson, R.M.; Sutherland, D.E.; Slavin, S.; Kim, T.; Kersey, J.; Simmons, R.S.

    1982-10-01

    Twenty-two patients at high risk to reject renal allografts have been treated with fractionated total lymphoid irradiation (FTLI) prior to transplantation of primary (2), secondary (16) or teritary (4) renal allografts. All patients undergoing retransplantation had rapidly rejected previous grafts. At 24 months following transplantation, 72% of grafts were functioning in the TLI group compared with a 38% graft function in an historical control group of recipients receiving secondary or tertiary grafts and treated with conventional immunosuppression. Important variables in determining success of transplantation following fractionated TLI include the dose of TLI, the interval from radiation to transplantation, and maintenance, post-transplant immunosuppressive therapy. Optimal results were achieved with 2500 rads delivered in 100 rad fractions followed by transplantation within two weeks, and a tapering prednisone schedule and maintenance azathioprine post-transplantation. Seventeen patients had significant complications of the radiation treatment and there was one death, prior to transplantation, associated with pneumonitis. In vitro assessment of immune function demonstrated marked peripheral T cell depletion and loss of in vitro responsiveness to mitogen and allogeneic stimulation following FTLI. The administration of donor bone marrow at the time of transplantation did not produce chimerism. The results suggest that when properly utilized FTLI can produce effective adjunctive immunosuppression for clinical transplantation.

  14. 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.

  15. 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

  16. Disruption mitigation using high pressure gas jets

    SciTech Connect

    Dennis G. Whyte

    2007-10-11

    The goal of this research is to establish credible disruption mitigation scenarios based on the technique of massive gas injection. Disruption mitigation seeks to minimize or eliminate damage to internal components that can occur due to the rapid dissipation of thermal and magnetic energy during a tokamak disruption. In particular, the focus of present research is extrapolating mitigation techniques to burning plasma experiments such as ITER, where disruption-caused damage poses a serious threat to the lifetime of internal vessel components. A majority of effort has focused on national and international collaborative research with large tokamaks: DIII-D, Alcator C-Mod, JET, and ASDEX Upgrade. The research was oriented towards empirical trials of gas-jet mitigation on several tokamaks, with the goal of developing and applying cohesive models to the data across devices. Disruption mitigation using gas jet injection has proven to be a viable candidate for avoiding or minimizing damage to internal components in burning plasma experiments like ITER. The physics understanding is progress towards a technological design for the required gas injection system in ITER.

  17. A high fraction of double-peaked narrow emission lines in powerful active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Lyu, Yang; Liu, Xin

    2016-11-01

    1 per cent of redshift z ˜ 0.1 active galactic nuclei (AGNs) show velocity splitting of a few hundred km s-1 in the narrow emission lines in spatially integrated spectra. Such line profiles have been found to arise from the bulk motion of ionized gas clouds associated with galactic-scale outflows, merging pairs of galaxies each harbouring a supermassive black hole (SMBH), and/or galactic-scale disc rotation. It remains unclear, however, how the frequency of narrow-line velocity splitting may depend on AGN luminosity. Here we study the correlation between the fraction of Type 2 AGNs with double-peaked narrow emission lines and AGN luminosity as indicated by [O III] λ5007 emission-line luminosity L_[O III]. We combine the sample of Liu et al. at z ˜ 0.1 with a new sample of 178 Type 2 AGNs with double-peaked [O III] emission lines at z ˜ 0.5. We select the new sample from a parent sample of 2089 Type 2 AGNs from the SDSS-III/Baryon Oscillation Spectroscopic Survey. We find a statistically significant (˜4.2σ) correlation between L_[O III] and the fraction of objects that exhibit double-peaked narrow emission lines among all Type 2 AGNs, corrected for selection bias and incompleteness due to [O III] line width, equivalent width, splitting velocity, and/or equivalent width ratio between the two velocity components. Our result suggests that galactic-scale outflows and/or merging pairs of SMBHs are more prevalent in more powerful AGNs, although spatially resolved follow-up observations are needed to resolve the origin(s) for the narrow-line velocity splitting for individual AGNs.

  18. 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.

  19. 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

  20. In situ synthesis of calcium phosphate-polycaprolactone nanocomposites with high ceramic volume fractions.

    PubMed

    Makarov, C; Gotman, I; Jiang, X; Fuchs, S; Kirkpatrick, C J; Gutmanas, E Y

    2010-06-01

    Biodegradable calcium phosphate-PCL nanocomposite powders with unusually high ceramic volume fractions (80-95%) and uniform PCL distribution were synthesized by a non-aqueous chemical reaction in the presence of the dissolved polymer. No visible polymer separation occurred during processing. Depending on the reagents combination, either dicalcium phosphate (DCP) or Ca-deficient HA (CDHA) was obtained. CDHA-PCL composite powders were high pressure consolidated at room temperature yielding dense materials with high compressive strengths. Such densification route provides the possibility of incorporating drug and proteins without damaging their biological activity. The CDHA-PCL composites were tested in osteoblastic and endothelial cell line cultures and were found to support the attachment and proliferation of both cell types.

  1. Zinc isotope fractionation during adsorption onto Mn oxyhydroxide at low and high ionic strength

    NASA Astrophysics Data System (ADS)

    Bryan, Allison L.; Dong, Shuofei; Wilkes, Elise B.; Wasylenki, Laura E.

    2015-05-01

    Marine ferromanganese sediments represent one of the largest sinks from global seawater for Zn, a critical trace metal nutrient. These sediments are variably enriched in heavier isotopes of Zn relative to deep seawater, and some are among the heaviest natural samples analyzed to date. New experimental results demonstrate that adsorption of Zn to poorly crystalline Mn oxyhydroxide results in preferential association of heavier isotopes with the sorbent phase. At low ionic strength our experimental system displayed a short-lived kinetic isotope effect, with light isotopes adsorbed to birnessite (Δ66/64Znadsorbed-dissolved ∼ -0.2‰). After 100 h the sense of fractionation was opposite, such that heavier isotopes were preferentially adsorbed at steady state, but the magnitude of Δ66/64Znadsorbed-dissolved was indistinguishable from zero (+0.05 ± 0.08‰). At high ionic strength, we observed preferential sorption of heavy isotopes, with a strong negative correlation between Δ66/64Znadsorbed-dissolved and the percentage of Zn on the birnessite. Values of Δ66/64Znadsorbed-dissolved ranged from nearly +3‰ at low surface loading to +0.16‰ at high surface loading. Based on previous EXAFS work we infer that Zn adsorbs first as tetrahedral, inner-sphere complexes at low surface loading, with preferential incorporation of heavier isotopes relative to the octahedral Zn species predominating in solution. As surface loading increases, so does the proportion of Zn adsorbing as octahedral complexes, thus diminishing the magnitude of fractionation between the dissolved and adsorbed pools of Zn. The magnitude of fractionation at high ionic strength is also governed by aqueous speciation of Zn in synthetic seawater; a substantial fraction of Zn ions reside in chloro complexes, which preferentially incorporate light Zn isotopes, and this drives the adsorbed pool to be heavier relative to the bulk solution than it was at low ionic strength. Our results explain the observation

  2. Effects of nitrosation on the chemical composition and epidermal carcinogenicity of the nitrogen-rich fraction of a high-boiling coal liquid.

    PubMed

    Wright, C W; Chess, E K; Renne, R A; Buschbom, R L

    1988-04-01

    An 800-850 degrees F solvent-refined coal-II liquid was fractionated into chemical classes to obtain the aliphatic hydrocarbons, polycyclic aromatic hydrocarbons (PAH), nitrogen-containing polycyclic aromatic compounds (NPAC), and hydroxy-substituted PAH (hydroxy-PAH). The isolated NPAC fraction was refractionated by chemical class both before and after undergoing a nitrosation reaction. The nitrosated and non-nitrosated refractionated NPAC fractions were further subfractionated into secondary amine (pyrroles), primary amine-enriched (amino-PAH), and tertiary amine (azaarene) classes. The PAH and hydroxy-PAH composition of the NPAC fraction increased upon nitrosation, whereas the amino-PAH fraction composition decreased upon nitrosation. Nitrosation of standards indicated the amino-PAH compounds reacted to form parent PAH, chloro-substituted PAH, and methoxy-substituted PAH when analyzed by high-resolution gas chromatography (GC) and GC/mass spectrometry (MS). Some easily oxidized PAH compounds reacted to form ketones and quinones. All other standard reference compounds, chosen to be representative of the major chemical classes of compounds present in coal liquefaction materials, were unchanged by the nitrosation reaction. The amino-PAH of the nitrosated NPAC fraction reacted to form parent and some chloro-substituted PAH when analyzed by low-voltage direct-probe MS in addition to the methods given above. Epidermal carcinogenesis studies with the PAH, NPAC, nitrosated NPAC, and hydroxy-PAH fractions isolated from the 800-850 degrees F coal liquid indicated the PAH and NPAC were the most important determiners of skin carcinogenesis, with the PAH giving a higher response than the NPAC. The tumorigenicity of the NPAC was drastically reduced by nitrosation, probably due to the destruction of the amino-PAH upon nitrosation.

  3. 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

  4. Highly fractionated I-type granites in NE China (I): geochronology and petrogenesis

    NASA Astrophysics Data System (ADS)

    Wu, Fu-yuan; Jahn, Bor-ming; Wilde, Simon A.; Lo, Ching-Hua; Yui, Tzen-Fu; Lin, Qiang; Ge, Wen-chun; Sun, De-you

    2003-02-01

    Northeastern (NE) China is the easternmost part of the Central Asian Orogenic Belt (CAOB), which is celebrated for its accretionary tectonics and the world's most important juvenile crust production in the Phanerozoic era. Abundant granitoids occur in the Great Xing'an, Lesser Xing'an and Zhangguangcai Ranges in NE China. This paper presents partial results of a series of studies on the granitoids from this region, aiming to understand their role in the building of new continental crust in eastern Asia. Three composite granite plutons (Xinhuatun, Lamashan and Yiershi) were chosen for geochemical and isotopic study in order to determine their emplacement ages and petrogenesis. Petrographically, they range from granodiorite (minor), monzogranite, syenogranite to alkali-feldspar granite. Quartz and perthitic feldspar are principal phases, accompanied by minor amounts of plagioclase, biotite (<5%) and other accessory minerals. In addition, many contain abundant miarolitic cavities which suggest that they were emplaced at shallow levels with extensive fractional crystallization. Geochemically, the granites are silica-rich, peraluminous and have high contents of alkalis. They invariably show enrichment in light rare earth elements (LREE) and significant negative Eu anomalies. All the granitic rocks demonstrate the characteristic negative anomalies in Ba, Nb, Sr, P, Eu, and Ti, and a positive anomaly in Pb in the spidergram. The emplacement of the Xinhuatun pluton took place at 184±4 Ma as revealed by zircon SHRIMP U-Pb data. This is also supported by the slightly younger Rb-Sr whole-rock (WR) isochron age of 173±3 Ma. A whole-rock (WR) Rb-Sr isochron age of 154±3 Ma was obtained for the Lamashan pluton, which is interpreted as close to the time of emplacement. The Yiershi pluton was intruded at about 140 Ma as evidenced by a zircon U-Pb age of 137±2 Ma and WR Rb-Sr isochron age of 143±5 Ma. Biotite-WR Rb-Sr isochrons and 40Ar/ 39Ar ages of feldspars allow us to

  5. 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.

  6. Performance of N2O and CO analyser for high-precision measurements of atmospheric mole fractions

    NASA Astrophysics Data System (ADS)

    Stanley, Kieran; O'Doherty, Simon

    2016-04-01

    N2O and CO are two important biogenic and anthropogenic greenhouse gases. N2O has a global warming potential approximately 300 times greater than CO2 on a per-molecule basis over a 100 year time horizon and is one of the most important factors affecting stratospheric ozone depletion. CO is a key gas in tropospheric photochemistry, constraining OH concentrations in the unpolluted atmosphere and the oxidising capacity in the troposphere. Due to the importance of N2O and CO as greenhouse and ozone depleting gases, precise high-frequency measurements of the two gases are necessary to better understand atmospheric mixing ratios. A number of different methods are available to measure the two gases, mainly based on chromatographic and reduction methods. The chromatographic method used to quantify atmospheric N2O mole fractions has not yet reached the WMO compatibility goal of ± 0.1 ppb. Over the past few years, new analytical techniques based on optical spectroscopy have been developed and become commercially available, providing near-real time data to high precision. In this presentation, we will give an overview of the performance of an Off Axis-Integrated Cavity Output Spectroscopy analyser with improvements made to temperature and pressure stability by the Scripps Institute of Oceanography. Results of the continuous repeatability measurement (referred to as precision by the manufacturers), short- and long-term repeatability, drift, temperature dependence, instrument linearity and H2O sensitivity will be presented.

  7. 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.

  8. 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.

  9. 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

    2012-09-01

    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.

  10. 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

    2012-09-01

    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. PMID:22840706

  11. Stable Chlorine Isotope Fractionation

    NASA Astrophysics Data System (ADS)

    Sharp, Z.

    2006-12-01

    Chlorine isotope partitioning between different phases is not well understood. Pore fluids can have δ37Cl values as low as -8‰, with neoform sediments having strongly positive values. Most strikingly, volcanic gases have δ37Cl values that cover a range in excess of 14‰ (Barnes et al., this meeting). The large range is difficult to explain in terms of equilibrium fractionation, which, although calculated to be very large for Cl in different oxidation states, should be less than 2‰ between chloride species (Schauble et al., 2003, GCA). To address the discrepancy between Nature and theory, we have measured Cl isotope fractionation for selected equilibrium and disequilibrium experiments in order to identify mechanisms that might lead to large fractionations. 1) NaCl (s,l) NaCl (v): NaCl was sealed in an evacuated silica tube and heated at one end, causing vaporization and reprecipitation of NaCl (v) at the cool end of the tube. The fractionation is 0.2‰ at 700°C (halite-vapor) and 0.7‰ at 800°C (liquid-vapor), respectively. The larger fractionation at higher temperature may be related to equilibrium fractionation between liquid and gas vs. `stripping' of the solid in the lower T experiments. 2) Sodalite NaCl(l): Nepheline and excess NaCl were sealed in a Pt crucible at 825°C for 48 hrs producing sodalite. The measured newly-formed sodalite-NaCl fractionation is -0.2‰. 3) Volatilization of HCl: Dry inert gas was bubbled through HCl solutions and the vapor was collected in a downstream water trap. There was no fractionation for 12.4M HCl (HCl fuming) vapor at 25°C. For a 1 M boiling HCl solution, the HCl-vapor fractionation was ~9‰. The difference is probably related to the degree of dissociation in the acid, with HCl dissolved in water for the highly acidic solutions, and dissociated H3O+ and Cl- for lower concentrations. The HCl volatilization experiments are in contrast to earlier vapor-liquid experiments in NaCl-H2O system, where fractionation was

  12. 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.

  13. Sulfur isotope fractionation during oxidation of sulfur dioxide: gas-phase oxidation by OH radicals and aqueous oxidation by H2O2, O3 and iron catalysis

    NASA Astrophysics Data System (ADS)

    Harris, E.; Sinha, B.; Hoppe, P.; Crowley, J. N.; Ono, S.; Foley, S.

    2011-08-01

    The oxidation of SO2 to sulfate is a key reaction in determining the role of sulfate in the environment through its effect on aerosol size distribution and composition. Sulfur isotope analysis has been used to investigate sources and chemistry of sulfur dioxide and sulfate in the atmosphere, however interpretation of measured sulfur isotope ratios is challenging due to a lack of reliable information on the isotopic fractionation involved in major transformation pathways. This paper presents measurements of the fractionation factors for the major atmospheric oxidation reactions for SO2: Gas-phase oxidation by OH radicals, and aqueous oxidation by H2O2, O3 and a radical chain reaction initiated by iron. The measured fractionation factor for 34S/32S during the gas-phase reaction is αOH = (1.0089±0.0007) - ((4±5)×10-5) T(°C). The measured fractionation factor for 34S/32S during aqueous oxidation by H2O2 or O3 is αaq=(1.0167±0.0019) - ((8.7±3.5) ×10-5) T(°C). The observed fractionation during oxidation by H2O2 and O3 appeared to be controlled primarily by protonation and acid-base equilbria of S(IV) in solution, and there was no significant difference between the fractionation produced by the two oxidants within the experimental error. The isotopic fractionation factor from a radical chain reaction in solution catalysed by iron is αFe = (0.989±0.0043) at 19 °C for 34S/32S. Fractionation was mass-dependent with regards to 33S for all the reactions investigated. The radical chain reaction mechanism was the only measured reaction that had a faster rate for the light isotopes, and will be particularly useful to determine the importance of the transition-metal catalysed oxidation pathway.

  14. 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.

  15. 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.

  16. 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. PMID:24486940

  17. 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

  18. 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

  19. 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

    2016-01-01

    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. PMID:27022829

  20. High resolution difference schemes for compressible gas dynamics

    SciTech Connect

    Woodward, P.; Colella, P.

    1980-07-30

    The advantages and disadvantages of four new high-resolution difference schemes, namely the von Neumann-Richtmyer, Godunovs, MUSCL and Glimms, for mathematically representing physical conditions in compressible gas flows are compared. (LCL)

  1. 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

  2. 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.

  3. Highly fractionation origin of the Himalayan leucogranites: Insights from the Kampa dome in South Tibet

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    Himalayan leucogranites are the best example presently known of granites generated during continental collision by partial melting of tectonically thickened crust. It is generally thought that these leucogranites were originated from partial melting of the high-grade metamorphosed pelitic rocks of the High Himalaya, and it represents one kind of in situ S-type intrusion during exhumation of the High Himalayan material mostly in the Miocene. However, the present study on the granites exposed in the Kampa dome indicates that the Himalayan leucogranites could be of highly fractionated origination. The Kampa dome is located in the middle part of the Tethyan Himalaya, and composed mostly by Early Paleozoic (ca. 500 Ma) orthogneiss with minor Oligocene (ca. 26 Ma) leucogranitic intrusions. These garnet-bearing two-mica leucogranites have high contents of SiO2 (74.4-75.6 wt. %), total alkali (8.0-9.6 wt. %), and low P2O5 contents (<0.03 wt. %), with aluminum saturation index (ASI) values of 1.14-1.28. Mineral indicating a nature of strongly peraluminous or S-type granitic magma is not present. Geochemically, these granites are characteristically enriched in lithophile trace elements, such as Rb, Cs, Y and depleted in Ba, Nb, Sr, P. In terms of REE elements, these granites show typical tetrad effects with significant negative Eu anomalies, which is also identified from apatite within granite. These features, together with high coherently saturation temperature of 635-675 °C for both zircon and monazite, suggest that the Kampa leucogranites might be a kind of high temperature magma originally, which had undergone an intensive crystal fractionation. The leucogranites have unradiogenic Nd isotope compositions (ɛNd(t)=-12.3 to -8.4), identical to those of the hosted granitic gneisses (ɛNd(t)=-14.8 to -8.8). Therefore, it was proposed that the leucogranites might be derived from the host gneisses of the Indian basement, but not from the metapelitic rocks as previously

  4. 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.

  5. Evaluating inhibition conditions in high-solids anaerobic digestion of organic fraction of municipal solid waste.

    PubMed

    Schievano, Andrea; D'Imporzano, Giuliana; Malagutti, Luca; Fragali, Emilio; Ruboni, Gabriella; Adani, Fabrizio

    2010-07-01

    High-solids anaerobic digestion (HSAD) processes, when applied to different types of organic fractions of municipal solid waste (OFMSW), may easily be subjected to inhibition due to organic overloading. In this study, a new approach for predicting these phenomena was proposed based on the estimation of the putrescibility (oxygen consumption in 20 h biodegradation, OD(20)) of the organic mixtures undergoing the HSAD process. Different wastes exhibiting different putrescibility were subjected to lab-scale batch-HSAD. Measuring the organic loading (OL) as volatile solids (VS) was found unsuitable for predicting overload inhibition, because similar VS contents corresponded to both inhibited and successful trials. Instead, the OL calculated as OD(20) was a very good indicator of the inhibiting conditions (inhibition started for OD(20)>17-18 g O(2)kg(-1)). This new method of predicting inhibition in the HSAD process of diverse OFMSW may be useful for developing a correct approach to the technology in very different contexts.

  6. High-Pressure Torsion of Ti: Synchrotron characterization of phase volume fraction and domain sizes

    NASA Astrophysics Data System (ADS)

    Bolmaro, Raúl E.; Sordi, Vitor L.; Ferrante, Maurizio; Brokmeier, Heinz-Günter; Kawasaki, Megumi; Langdon, Terence G.

    2014-08-01

    Rods of grade 2 Ti were processed by Equal-Channel Angular Pressing (ECAP) (phi = 120° at 573 K) employing 2, 4 and 6 passes. The same billets were further deformed by High- Pressure Torsion (HPT) at room temperature, varying both the hydrostatic pressure (1 and 6 GPa) and the number of rotations (n = 1 and 5). The ECAP and HPT samples were studied by synchrotron radiation at DESY-Petra III GEMS line. On the ECAP samples, textures were thus determined while for both ECAP and HPT samples the measurements were further analyzed by MAUD. Domain sizes and phase volume fractions were determined as a function of the radial direction of the samples. Alpha and Omega phases were detected in different amounts depending mostly on hydrostatic pressure and shear deformation. These transition phases can be pressure-induced during HPT processing and the results of Vickers microhardness measurements were related to the processing parameters and to the amounts of these phases.

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  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. PMID:25635250

  13. Mass-Dependent and -Independent Fractionation of Mercury Isotope during Gas-Phase Oxidation of Elemental Mercury Vapor by Atomic Cl and Br.

    PubMed

    Sun, Guangyi; Sommar, Jonas; Feng, Xinbin; Lin, Che-Jen; Ge, Maofa; Wang, Weigang; Yin, Runsheng; Fu, Xuewu; Shang, Lihai

    2016-09-01

    This study presents the first measurement of Hg stable isotope fractionation during gas-phase oxidation of Hg(0) vapor by halogen atoms (Cl(•), Br(•)) in the laboratory at 750 ± 1 Torr and 298 ± 3 K. Using a relative rate technique, the rate coefficients for Hg(0)+Cl(•) and Hg(0)+Br(•) reactions are determined to be (1.8 ± 0.5) × 10(-11) and (1.6 ± 0.8) × 10(-12) cm(3) molecule(-1) s(-1), respectively. Results show that heavier isotopes are preferentially enriched in the remaining Hg(0) during Cl(•) initiated oxidation, whereas being enriched in the product during oxidation by Br(•). The fractionation factors for (202)Hg/(198)Hg during the Cl(•) and Br(•) initiated oxidations are α(202/198) = 0.99941 ± 0.00006 (2σ) and 1.00074 ± 0.00014 (2σ), respectively. A Δ(199)Hg/Δ(201)Hg ratio of 1.64 ± 0.30 (2σ) during oxidation of Hg(0) by Br atoms suggests that Hg-MIF is introduced by the nuclear volume effect (NVE). In contrast, the Hg(0) + Cl(•) reaction produces a Δ(199)Hg/Δ(201)Hg-slope of 1.89 ± 0.18 (2σ), which in addition to a high degree of odd-mass-number isotope MIF suggests impacts from MIF effects other than NVE. This reaction also exhibits significant MIF of (200)Hg (Δ(200)Hg, up to -0.17‰ in the reactant) and is the first physicochemical process identified to trigger (200)Hg anomalies that are frequently detected in atmospheric samples. PMID:27501307

  14. 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.

  15. 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

  16. High concentrated gas hydrate zone imaged in seismic data

    NASA Astrophysics Data System (ADS)

    Kobayashi, T.; Saeki, T.; Oikawa, N.; Inamori, T.; Fujii, T.; Takayama, T.; Hayashi, M.; Nakamizu, M.

    2006-12-01

    Japan Oil, Gas and Metals National Corporation (JOGMEC), as a member of MH21 Research Consortium, takes charge of a study of the Research for Resources Assessment, and is pursuing a possibility that gas hydrate, which is presumed to be distributed around ocean area of Japan, will be energy resources. As part of the study, 3D seismic survey was conducted from Tokai-oki to Kumano-nada in the eastern Nankai Trough by METI (Ministry of Economy, Trade and Industry) in 2002 under the national program of assessment for gas hydrates as energy resources. As well as 3D seismic survey, drilling program was conducted in this area and information of physical property was acquired. Additionally, velocity analysis and seismic attribute analysis were conducted. It is revealed that gas hydrate zone is correlated with high resistivity and high velocity, and a lot of gas hydrates are found in turbidite sand with much porosity. JOGMEC is conducting analysis of seismic data and is doing resources assessment of gas hydrate compiling information of physical property which was acquired by drilling, result of velocity analysis, and result of seismic attribute analysis. This time, we introduce some seismic images of high concentrated gas hydrate zone appears in Tokai-oki area.

  17. 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.

  18. 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.

  19. 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. PMID:25133268

  20. Single fraction multimodal image guided focal salvage high-dose-rate brachytherapy for recurrent prostate cancer

    PubMed Central

    Rischke, Hans-Christian; Meyer, Philipp Tobias; Knobe, Sven; Volgeova-Neher, Natalja; Kollefrath, Michael; Jilg, Cordula Annette; Grosu, Anca Ligia; Baltas, Dimos; Kroenig, Malte

    2016-01-01

    Purpose We present a novel method for treatment of locally recurrent prostate cancer (PCa) following radiation therapy: focal, multimodal image guided high-dose-rate (HDR) brachytherapy. Material and methods We treated two patients with recurrent PCa after primary (#1) or adjuvant (#2) external beam radiation therapy. Multiparametric magnetic resonance imaging (mpMRI), choline, positron emission tomography combined with computed tomography (PET/CT), or prostate-specific membrane antigen (PSMA)-PET combined with CT identified a single intraprostatic lesion. Positron emission tomography or magnetic resonance imaging – transrectal ultrasound (MRI-TRUS) fusion guided transperineal biopsy confirmed PCa within each target lesion. We defined a PET and mpMRI based gross tumor volume (GTV). A 5 mm isotropic margin was applied additionally to each lesion to generate a planning target volume (PTV), which accounts for technical fusion inaccuracies. A D90 of 18 Gy was intended in one fraction to each PTV using ultrasound guided HDR brachytherapy. Results Six month follow-up showed adequate prostate specific antygen (PSA) decline in both patients (ΔPSA 83% in patient 1 and ΔPSA 59.3% in patient 2). Follow-up 3-tesla MRI revealed regressive disease in both patients and PSMA-PET/CT showed no evidence of active disease in patient #1. No acute or late toxicities occurred. Conclusions Single fraction, focal, multimodal image guided salvage HDR brachytherapy for recurrent prostate cancer is a feasible therapy for selected patients with single lesions. This approach has to be evaluated in larger clinical trials. PMID:27504134

  1. Transport simulations of ITER with broad density profiles and high radiative fraction

    NASA Astrophysics Data System (ADS)

    Becker, G.

    1995-08-01

    Special versions of the 1.5-D BALDUR predictive transport code are used to explore the confinement in the ignited ITER EDA by self-consistent calculations. The code computes 2-D equilibria and solves 1-D transport equations in the bulk and scrape-off layer with empirical transport coefficients for the ohmic, L and ELMy H mode regimes. The emphasis is on scenarios with flat density profiles and high, fixed radiative power in the main chamber due to the seeded impurities argon and neon. It is shown that self-sustained steady state thermonuclear burn is achieved for 370 s and is compatible with the flat density profiles and strong radiative cooling. The necessary local energy and particle transport are presented. In the argon and neon scenarios, the required radiation corrected energy confinement times are 4.1 and 3.5 s, respectively, which are achievable according to the ITER ELMy H mode scaling. The advantage of neon originates from its smaller radiative loss within the separatrix of 37% of the total radiation in the main chamber, compared with 60% in the case of argon. A significant radiative loss from the confinement zone, mainly by bremsstrahlung, cannot be avoided. It raises the required energy confinement time and is the price to be paid for reduction of the divertor heat load by radiative cooling in the main chamber. In steady state, a helium fraction of 5% is computed. The fractions of helium, argon and neon and the resulting fuel dilution are considerably lower than with peaked density profiles

  2. Metal-sulfide melt non-interconnectivity in silicates, even at high pressure, high temperature, and high melt fractions

    SciTech Connect

    Minarik, W.G.; Ryerson, F.J.

    1996-01-01

    The authors have investigated the textural microstructure of iron-nickel-sulfur melts in contact with olivine, pyroxene, and the modified-spinel polymorph of olivine. The experiments were conducted at 1,500 C and pressures ranging from 1 to 17 GPa. For compositions more metal-rich than the monosulfide, including the eutectic composition, the metal sulfide melt has a dihedral angle greater than 60{degree} and does not form an interconnected grain-edge fluid. Increasing pressure does not measurably alter the dihedral angles. Textural evolution results in coarsening of the sulfide melt pockets, resulting in large pockets surrounded by many silicate grains and separated from one another by melt-free grain edges. Chemical communication between these large pockets is limited to lattice and grain-boundary diffusion. Due to the large interfacial energy between sulfide melt and silicates, sulfide melts are unable to separate from solid silicate via grain-boundary percolation and remain stranded in isolated melt pockets. Sulfide melt in excess of the critical melt fraction (5--25%) will develop a transient interconnectivity as sulfide collects into larger melt pockets and interconnectivity is pinched off. Efficient separation of core-forming sulfide melts from silicate requires either melting of the silicate matrix or a very large fraction of metal-sulfide melt (perhaps as large as 40%).

  3. 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

  4. Progress Toward Steady State Tokamak Operation Exploiting the high bootstrap current fraction regime

    NASA Astrophysics Data System (ADS)

    Ren, Q.

    2015-11-01

    Recent DIII-D experiments have advanced 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. Fully noninductive plasmas with extremely high values of the poloidal beta, βp >= 4 , have been sustained at βT >= 2 % for long durations with excellent energy confinement quality (H98y,2 >= 1 . 5) and internal transport barriers (ITBs) generated at large minor radius (>= 0 . 6) in all channels (Te, Ti, ne, VTf). Large bootstrap fraction (fBS ~ 80 %) has been obtained with high βp. ITBs have been shown to be compatible with steady state operation. Because of the unusually large ITB radius, normalized pressure is not limited to low βN values by internal ITB-driven modes. βN up to ~4.3 has been obtained by optimizing the plasma-wall distance. The scenario is robust against several variations, including replacing some on-axis with off-axis neutral beam injection (NBI), adding electron cyclotron (EC) heating, and reducing the NBI torque by a factor of 2. This latter observation is particularly promising for extension of the scenario to EAST, where maximum power is obtained with balanced NBI injection, and to a reactor, expected to have low rotation. However, modeling of this regime has provided new challenges to state-of-the-art modeling capabilities: quasilinear models can dramatically underpredict the electron transport, and the Sauter bootstrap current can be insufficient. The analysis shows first-principle NEO is in good agreement with experiments for the bootstrap current calculation and ETG modes with a larger saturated amplitude or EM modes may provide the missing electron transport. Work supported in part by the US DOE under DE-FC02-04ER54698, DE-AC52-07NA

  5. A comparison of solar wind and estimated solar system xenon abundances - A test for solid/gas fractionation in the solar nebula

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    The solar Xe elemental abundance is determined here using solar wind measurements from lunar ilmenites which are normalized to Si by spacecraft data. The results are compared with estimated abundances assuming no fractionation. When corrected for solar wind/photospheric fractionation, the Xe-130 abundance given by surface layer oxidation of ilmenite from solid 71501 exposed within the last 200 m.y. is 0.24 +/- 0.09 normalized to Si = 10 exp 6. This is indistinguishable from estimates made assuming no solid/gas fractionation. Results from breccia 79035 ilmenite exposed at least 1 Gyr ago indicate that the solar wind Xe flux may have been significantly higher relative to other noble gases, perhaps due to more efficient Xe ionization. If this is true, fluxes of C and S, which have first ionization potentials similar to Xe, should also be higher in the ancient solar wind from the same time period.

  6. Noble gas clusters and nanoplasmas in high harmonic generation

    NASA Astrophysics Data System (ADS)

    Aladi, M.; Bolla, R.; Rácz, P.; Földes, I. B.

    2016-02-01

    We report a study of high harmonic generation from noble gas clusters of xenon atoms in a gas jet. Harmonic spectra were investigated as a function of backing pressure, showing spectral shifts due to the nanoplasma electrons in the clusters. At certain value of laser intensity this process may oppose the effect of the well-known ionization-induced blueshift. In addition, these cluster-induced harmonic redshifts may give the possibility to estimate cluster density and cluster size in the laser-gas jet interaction range.

  7. 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.

  8. An enhanced fraction of starbursting galaxies among high Eddington ratio AGNs

    NASA Astrophysics Data System (ADS)

    Bernhard, E.; Mullaney, J. R.; Daddi, E.; Ciesla, L.; Schreiber, C.

    2016-07-01

    We investigate the star-forming properties of 1620 X-ray selected active galactic nuclei (AGN) host galaxies as a function of their specific X-ray luminosity (i.e. X-ray luminosity per unit host stellar mass) - a proxy of the Eddington ratio. Our motivation is to determine whether there is any evidence of a suppression of star formation at high Eddington ratios, which may hint towards `AGN feedback' effects. Star formation rates (SFRs) are derived from fits to Herschel-measured far-infrared spectral energy distributions, taking into account any contamination from the AGN. Herschel-undetected AGNs are included via stacking analyses to provide average SFRs in bins of redshift and specific X-ray luminosity (spanning 0.01 lesssim L_X/M_{ast } lesssim 100 L_{{⊙}} M_{{⊙}}^{-1}). After normalizing for the effects of mass and redshift arising from the evolving galaxy main sequence, we find that the SFRs of high specific luminosity AGNs are slightly enhanced compared to their lower specific luminosity counterparts. This suggests that the SFR distribution of AGN hosts changes with specific X-ray luminosity, a result reinforced by our finding of a significantly higher fraction of starbursting hosts among high specific luminosity AGNs compared to that of the general star-forming galaxy population (i.e. 8-10 per cent versus 3 per cent). Contrary to our original motivation, our findings suggest that high specific luminosity AGNs are more likely to reside in galaxies with enhanced levels of star formation.

  9. A Gas-Filled Calorimeter for High Intensity Beam Environments

    NASA Astrophysics Data System (ADS)

    Abrams, Robert; Ankenbrandt, Harles; Flanagan, Gene; Hauptman, John; Kahn, Steven; Lee, Sehwook; Notani, Masahiro

    We describe a novel gas-Cherenkov calorimeter, which detects Cherenkov light showers emitted in an array of thin metal tubes or channels filled with gas. The materials are not vulnerable to radiation damage, and the detector is inherently fast and able to operate in high rate environments. Future accelerators such as the ILC and a muon collider will need fast, radiation-tolerant detectors for monitoring beams and beam halos, and detectors are needed that can operate in the presence of high particle rates. Such detectors will also be useful for high rate environments at upgraded facilities such as RHIC, CEBAF II, and at Fermilab's Project X.

  10. Comparison of nitrous oxide (N2O) analyzers for high-precision measurements of atmospheric mole fractions

    NASA Astrophysics Data System (ADS)

    Lebegue, Benjamin; Schmidt, Martina; Ramonet, Michel; Wastine, Benoit; Yver Kwok, Camille; Laurent, Olivier; Belviso, Sauveur; Guemri, Ali; Philippon, Carole; Smith, Jeremiah; Conil, Sebastien

    2016-03-01

    Over the last few decades, in situ measurements of atmospheric N2O mole fractions have been performed using gas chromatographs (GCs) equipped with electron capture detectors. This technique, however, becomes very challenging when trying to detect the small variations of N2O as the detectors are highly nonlinear and the GCs at remote stations require a considerable amount of maintenance by qualified technicians to maintain good short-term and long-term repeatability. With new robust optical spectrometers now available for N2O measurements, we aim to identify a robust and stable analyzer that can be integrated into atmospheric monitoring networks, such as the Integrated Carbon Observation System (ICOS). In this study, we present the most complete comparison of N2O analyzers, with seven analyzers that were developed and commercialized by five different companies. Each instrument was characterized during a time period of approximately 8 weeks. The test protocols included the characterization of the short-term and long-term repeatability, drift, temperature dependence, linearity and sensitivity to water vapor. During the test period, ambient air measurements were compared under field conditions at the Gif-sur-Yvette station. All of the analyzers showed a standard deviation better than 0.1 ppb for the 10 min averages. Some analyzers would benefit from improvements in temperature stability to reduce the instrument drift, which could then help in reducing the frequency of calibrations. For most instruments, the water vapor correction algorithms applied by companies are not sufficient for high-precision atmospheric measurements, which results in the need to dry the ambient air prior to analysis.

  11. Optimization of the Safety Factor Profile for High Noninductive Current Fraction Discharges in DIII-D

    SciTech Connect

    Ferron, J.R.; Holcomb, C T; Luce, T.C.; Politzer, P. A.; Turco, F.; White, A. E.; DeBoo, J. C.; Doyle, E. J.; Hyatt, A. W.; La Haye, R.; Murakami, Masanori; Petrie, T W; Petty, C C.; Rhodes, T. L.; Zeng, L.

    2011-01-01

    In order to assess the optimum q profile for discharges in DIII-D with 100% of the current driven noninductively (f(NI) = 1), the self-consistent response of the plasma profiles to changes in the q profile was studied in high f(NI), high beta(N) discharges through a scan of q(min) and q(95) at two values of beta(N). As expected, both the bootstrap current fraction, f(BS), and f(NI) increased with q(95). The temperature and density profiles were found to broaden as either q(min) or beta(N) is increased. A consequence is that f(BS) does not continue to increase at the highest values of q(min). A scaling function that depends on q(min), q(95), and the peaking factor for the thermal pressure was found to represent well the f(BS)/beta(N) inferred from the experimental profiles. The changes in the shapes of the density and temperature profiles as beta(N) is increased modify the bootstrap current density (J(BS)) profile from peaked close to the axis to relatively flat in the region between the axis and the H-mode pedestal. Therefore, significant externally driven current density in the region inside the H-mode pedestal is required in addition to J(BS) in order to match the profiles of the noninductive current density (J(NI)) to the desired total current density (J). In this experiment, the additional current density was provided mostly by neutral beam current drive with the neutral-beam-driven current fraction 40-90% of f(BS). The profiles of J(NI) and J were most similar at q(min) approximate to 1.35-1.65, q(95) approximate to 6.8, where f(BS) is also maximum, establishing this q profile as the optimal choice for f(NI) = 1 operation in DIII-D with the existing set of external current drive sources.

  12. 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.

  13. High-resolution droplet-based fractionation of nano-LC separations onto microarrays for MALDI-MS analysis.

    PubMed

    Küster, Simon K; Pabst, Martin; Jefimovs, Konstantins; Zenobi, Renato; Dittrich, Petra S

    2014-05-20

    We present a robust droplet-based device, which enables the fractionation of ultralow flow rate nanoflow liquid chromatography (nano-LC) eluate streams at high frequencies and high peak resolution. This is achieved by directly interfacing the separation column to a micro T-junction, where the eluate stream is compartmentalized into picoliter droplets. This immediate compartmentalization prevents peak dispersion during eluate transport and conserves the chromatographic performance. Subsequently, nanoliter eluate fractions are collected at a rate of one fraction per second on a high-density microarray to retain the separation with high temporal resolution. Chromatographic separations of up to 45 min runtime can thus be archived on a single microarray possessing 2700 sample spots. The performance of this device is demonstrated by fractionating the separation of a tryptic digest of a known protein mixture onto the microarray chip and subsequently analyzing the sample archive using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). Resulting peak widths are found to be significantly reduced compared to standard continuous flow spotting technologies as well as in comparison to a conventional nano-LC-electrospray ionization-mass spectrometry interface. Moreover, we demonstrate the advantage of our high-definition nanofractionation device by applying two different MALDI matrices to all collected fractions in an alternating fashion. Since the information that is obtained from a MALDI-MS measurement depends on the choice of MALDI matrix, we can extract complementary information from neighboring spots containing almost identical composition but different matrices. PMID:24725135

  14. 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.

  15. 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.

  16. Witnessing molecular cloud formation from HI gas in high-latitude clouds

    NASA Astrophysics Data System (ADS)

    Tachihara, Kengo; Hattori, Momo; Yamamoto, Hiroaki; Okamoto, Ryuji; Hayakawa, Takahiro; Fukui, Yasuo

    2015-08-01

    The formation of molecular cloud is a fundamental process in terms of the cycle and evolution of matter in the universe. Its detail process is, however, not well understood yet, despite the importance for the investigation of initial condition of molecular clouds. From the observational point of view, it can be best studied in high-latitude clouds where obstacles of the galactic contamination and strong UV radiation decline. It is known that the atomic interstellar gas consist of warm neutral medium (WNM) and cold neutral medium (CNM), and the molecular gas formation is believed to take place in the dense CNM, which is suggested to have small-scale structures by theoretical calculations (e.g., Inoue & Inutsuka 2012). In order to avoid confusions of many overlapping structures, relatively high resolution HI data of the GALFA survey at high-latitude clouds MBM 53-55 are used. We decompose the multiple velocity components at the interface region between molecular and atomic clouds, and succeeded to resolve ~ 1 pc scale atomic CNM with a density of ~ 10 cm-3. As compared with the CO data obtained by the NANTEN telescope, small fraction of the HI components with small velocity dispersions appear to have counterpart molecular gas. The physical properties of these small-scale HI gas give us clues of not only the conditions of molecular formation but also the origins of cloud structures and interstellar turbulence.

  17. 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.

  18. 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. PMID:25010457

  19. Fractionation of Highly Siderophile Elements in Refertilized Mantle: Implications for the Os Isotope Composition of Basalts

    NASA Astrophysics Data System (ADS)

    Marchesi, C.; Dale, C. W.; Garrido, C. J.; Pearson, D. G.; Bosch, D.; Bodinier, J. L.; Gervilla, F.; Hidas, K.

    2014-12-01

    Highly fertile lherzolite and spinel websterite in the Ronda peridotite massif are enriched in Pt and Pd compared to Os, Ir, Ru and Re. The fractionation of the highly siderophile elements (HSE) in these rocks was produced by reaction of melt with their peridotite and pyroxenite precursors. Modelling indicates that upon reaction primary HSE hosts were dissolved and magmatic sulphides precipitated, largely erasing the original HSE signature of reacting protoliths. The budget of HSE in the melt was controlled by sulphide-silicate partitioning or entrainment of molten sulphide in silicate melt. Rhenium was likely removed from precursor peridotite and pyroxenite by previous melt extraction. Refertilization of peridotite by melts increased Al2O3, CaO, Pt, Pd contents and 187Os/188Os beyond typical values for mantle peridotite and the primitive upper mantle. The interaction of melts with residual peridotite and pyroxenite, as illustrated in the Ronda massif, can generate radiogenic-Os-enriched domains in the mantle with high melt productivity, higher Pt/Os and Pt/Re than common peridotite, and lower Re/Os than typical pyroxenite. As also previously proposed for pyroxenites, these "hybrid" domains can account for the difference in Os isotope compositions between many basalts (e.g., MORB and OIB) and common depleted mantle peridotites. Moreover, the presence of these enriched hybrid components in the mantle, evolved over sufficient timescales and in geologically reasonable proportions, may account for the 186Os-187Os enrichment of plume lavas without requiring a chemical contribution from the core.

  20. Fractionation of highly siderophile elements in refertilized mantle: Implications for the Os isotope composition of basalts

    NASA Astrophysics Data System (ADS)

    Marchesi, Claudio; Dale, Christopher W.; Garrido, Carlos J.; Pearson, D. Graham; Bosch, Delphine; Bodinier, Jean-Louis; Gervilla, Fernando; Hidas, Károly

    2014-08-01

    Highly fertile lherzolite and spinel websterite in the Ronda peridotite massif are enriched in Pt and Pd compared to Os, Ir, Ru and Re. The fractionation of the highly siderophile elements (HSE) in these rocks was produced by reaction of melt with their peridotite and pyroxenite precursors. Modeling indicates that upon reaction primary HSE hosts were dissolved and magmatic sulphides precipitated, largely erasing the original HSE signature of reacting protoliths. The budget of HSE in the melt was controlled by sulphide-silicate partitioning or entrainment of molten sulphide in silicate melt. Rhenium was likely removed from precursor peridotite and pyroxenite by previous melt extraction. Refertilization of peridotite by melts increased Al2O3, CaO, Pt, Pd contents and 187Os/188Os beyond typical values for mantle peridotite and the primitive upper mantle. The interaction of melts with residual peridotite and pyroxenite, as illustrated in the Ronda massif, can generate radiogenic-Os-enriched domains in the mantle with high melt productivity, higher Pt/Os and Pt/Re than common peridotite, and lower Re/Os than typical pyroxenite. As also previously proposed for pyroxenites, these “hybrid” domains can account for the difference in Os isotope compositions between many basalts (e.g., MORB and OIB) and common depleted mantle peridotites. Moreover, the presence of these enriched hybrid components in the mantle, evolved over sufficient timescales and in geologically reasonable proportions, may account for the 186Os-187Os enrichment of plume lavas without requiring a chemical contribution from the core.

  1. Lack of intracellular bubble formation in microorganisms at very high gas supersaturations.

    PubMed

    Hemmingsen, E A; Hemmingsen, B B

    1979-12-01

    Eucaryotic unicellular (a yeast, a cellular slime mold, and various protozoans) and two multicellular (aschelminths) microorganisms were saturated with gas at high pressures and rapidly decompressed. No effect was observed with pressures of argon up to 125 atm, nitrogen up to 175 atm, and helium up to 350 atm, showing that the induced gas supersaturations did not cause intracellular bubbles to form. With 25--50 atm higher gas pressures, the decompression usually produced killing and cell rupture, although differences in tolerances existed among the various organisms. Substantial fractions of the populations survived gas supersaturations well above the threshold values for massive spontaneous nucleation of bubbles in the water. When killing occurred, external rather than internal bubbles appeared to be the cause. Even with the 300 atm argon or nitrogen pressures, yeast cells were unaffected, apparently because of the external protection provided by their cell wall. It is concluded that the gas supersaturations required for intracellular formation of bubbles generally are at least equal to and probably higher than the bubble nucleation thresholds for water or aqueous solutions. PMID:395143

  2. On the predictive power of the minimum energy condition. 2: Fractional calorimeter behaviour in the diffuse high energy gamma emission of spiral galaxies

    NASA Astrophysics Data System (ADS)

    Pohl, M.

    1994-07-01

    In this paper we investigate the high energy gamma ray emission from spiral galaxies. The calculations are based on equilibrium spectra for cosmic ray protons and electrons, respectively, which have been derived in an earlier paper (Pohl 1993a). There, the cosmic ray particles are assumed to undergo simultaneously transport by diffusion, escape, and energy losses by ionization, inelastic scattering, bremsstrahlung, adiabatic cooling and radiative losses. In the thick target case a fractional calorimeter behavior occurs both for leptonic and for hadronic gamma ray emission: the resultant gamma ray flux depends solely on the injection rate of cosmic rays and on a fraction factor. This fraction factor is in fact a combination of two: the first is the fraction of cosmic rays which meet the interaction targets like protons or thermal gas. The second is the fraction of the gamma ray producing loss mechanism to the total losses in the gas disk. Once reliable gamma ray and radio spectra of spiral galaxies are obtained these calorimeter fractions may help to gain information about the physical state of the interstellar medium in these objects, especially on the proton-to-electron ratio in cosmic rays. The integrated radio spectra of spiral galaxies tell us whether these systems form a thick target for cosmic rays or not. With the minimum energy consumption for the magnetic field strength we are then able to predict explicitely the gamma ray flux from these objects in a broad energy range. The hitherto promising candidates M 31 and M 82 will not be detected by EGRET, since their integrated flux is les than 2 x 10-8ph./sq cm/sec. It appears that our Galaxy is the only object apart from Large Magellanic Cloud (LMC) which we observe with sufficient accuracy to base clues on the gamma ray emission. Since via the calorimeter effects spiral galaxies can regulate themselves, the minimum energy condition has a predictive power which is much more precise than earlier estimated

  3. High-yield resin fractionation using a liquid/liquid centrifuge

    NASA Astrophysics Data System (ADS)

    Wanat, Stan F.; Rahman, M. D.; Narasimhan, Balaji; McKenzie, Douglas S.; Cook, Michelle M.

    2000-06-01

    Resins used in photoresist manufacturing are often relatively expensive once processing steps (fractionation e.g.) and yield losses are factored into the net cost. We have previously reported on the merits of using an economically more attractive fractionation process using a liquid/liquid centrifuge. Further refinements of this method indicate that waste streams could be reduced by recycling the extractant phase and that lower molecular weight fractions removed from the starting resin might be used in making other resist ingredients [speed enhancers, photoactive compound (PAC) backbones e.g.]. Both of these improvements would reduce the overall manufacturing costs of making resist raw materials and the final products made with them.

  4. Properties of High Volume Fraction Fly Ash/Al Alloy Composites Produced by Infiltration Process

    NASA Astrophysics Data System (ADS)

    Kountouras, D. T.; Stergioudi, F.; Tsouknidas, A.; Vogiatzis, C. A.; Skolianos, S. M.

    2015-09-01

    In the present study, pressure infiltration is employed to synthesize aluminum alloy 7075-fly ash composites. The microstructure and chemical composition of the fly ash and the produced composite material was examined using optical and scanning electron microscopy, as well as x-ray diffraction. Several properties of the produced composite material were examined and evaluated including macro-hardness, wear, thermal expansion, and corrosion behavior. The wear characteristics of the composite, in the as-cast conditions, were studied by dry sliding wear tests. The corrosion behavior of composite material was evaluated by means of potentiodynamic corrosion experiments in a 3.5 wt.% NaCl solution. The composite specimens exhibit a homogeneous distribution of fly ash particles and present enhanced hardness values, compared to the matrix material. The high volume fraction of the fly ash reinforcement (>40%) in the composite material led to increased wear rates, attributed to the fragmentation of the fly ash particles. However, the presence of fly ash particles in the Al alloy matrix considerably decreased the coefficiency of thermal expansion, while resulting in an altered corrosion mechanism of the composite material with respect to the matrix alloy.

  5. 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.

  6. Oxygen Isotope Fractionation Effects in Soil Water via Cations Adsorbed to High-CEC Clays

    NASA Astrophysics Data System (ADS)

    Oerter, E.; Finstad, K.; Schaefer, J.; Goldsmith, G. R.; Dawson, T. E.; Amundson, R.

    2012-12-01

    In isotope-based approaches to hydrology, soil and sediment are implicitly considered to be an inert matrix in which water resides or moves. Yet, this assumption is inconsistent with the fact that soils contain a wide range of solutes, and highly variable concentrations of chemically reactive clay particles, all of which may react with bulk water and create pools of energetically differing water with varying isotope compositions. The empirical basis of this hypothesis is the work of Sofer and Gat (1972, EPSL, 15(3)), who showed that the formation of hydration spheres around cations in aqueous solutions fractionate oxygen isotopes of water in ways that appear to be dependent on the cation's ionic potential and concentration. Because soil solutions commonly have high solid to fluid ratios, the potential for solids to create substantial pools of low free energy water, with corresponding isotope fractionation of the free and low energy waters, may be a common process. The potential for this to create measurable isotopic effects would be most evident in soils with high Cation Exchange Capacity (CEC). In order to test this hypothesis, montmorillonite (CEC ≈ 100 meq/100g), kaolinite (CEC≈10) and quartz (CEC≈0) mineral powders were saturated with 3M MgCl2 and KCl solutions (separately), rinsed with methanol and dried to saturate all available CEC sites with either Mg or K cations. Triplicate sets of monominerallic-deionized water mixtures were created at 5, 25, 50, 75 and 95% gravimetric water content. Each set of samples was then subjected to one of three water extraction techniques designed to access specific "pools" of soil water: (1) direct equilibration with CO2 to sample the soil's "free water", i.e. water not adsorbed to cations via hydration spheres; (2) centrifugation to simulate permanent wilting point conditions, thereby yielding most micro-pore, macro-pore, and free water; and (3) cryogenic vacuum distillation to recover all the soil water (free, pore and

  7. Sulfur isotope fractionation during oxidation of sulfur dioxide: gas-phase oxidation by OH radicals and aqueous oxidation by H2O2, O3 and iron catalysis

    NASA Astrophysics Data System (ADS)

    Harris, E.; Sinha, B.; Hoppe, P.; Crowley, J. N.; Ono, S.; Foley, S.

    2012-01-01

    The oxidation of SO2 to sulfate is a key reaction in determining the role of sulfate in the environment through its effect on aerosol size distribution and composition. Sulfur isotope analysis has been used to investigate sources and chemical processes of sulfur dioxide and sulfate in the atmosphere, however interpretation of measured sulfur isotope ratios is challenging due to a lack of reliable information on the isotopic fractionation involved in major transformation pathways. This paper presents laboratory measurements of the fractionation factors for the major atmospheric oxidation reactions for SO2: Gas-phase oxidation by OH radicals, and aqueous oxidation by H2O2, O3 and a radical chain reaction initiated by iron. The measured fractionation factor for 34S/32S during the gas-phase reaction is αOH = (1.0089±0.0007)-((4±5)×10-5) T(°C). The measured fractionation factor for 34S/32S during aqueous oxidation by H2O2 or O3 is αaq = (1.0167±0.0019)-((8.7±3.5) ×10-5)T(°C). The observed fractionation during oxidation by H2O2 and O3 appeared to be controlled primarily by protonation and acid-base equilibria of S(IV) in solution, which is the reason that there is no significant difference between the fractionation produced by the two oxidants within the experimental error. The isotopic fractionation factor from a radical chain reaction in solution catalysed by iron is αFe = (0.9894±0.0043) at 19 °C for 34S/32S. Fractionation was mass-dependent with regards to 33S/32S for all the reactions investigated. The radical chain reaction mechanism was the only measured reaction that had a faster rate for the light isotopes. The results presented in this study will be particularly useful to determine the importance of the transition metal-catalysed oxidation pathway compared to other oxidation pathways, but other main oxidation pathways can not be distinguished based on stable sulfur isotope measurements alone.

  8. Pressure Dependent Mass Fraction in Noble Gas Mass Spectrometers: A Possible Explanation for the Excessive Dispersion in the EARTHTIME Fish Canyon/Alder Creek Inter-Calibration Experiment

    NASA Astrophysics Data System (ADS)

    Turrin, B. D.; Swisher, C. C.; Mana, S.

    2011-12-01

    Mass spectrometer fractionation bias (mass discrimination) is a ubiquitous phenomenon in noble gas mass spectroscopy and must be corrected for in order to obtain accurate-high precision isotopic ratios that are used in isotopic age calculations. Temporal variations in mass fractionation are well known phenomena and have been reported in several studies (eg. Turrin et al., 2010 and references therein). Here we report on the pressure dependency on mass spectrometer fractionation bias. In our experiment, we varied by a factor of five the signal size of aliquots of atmospheric argon delivered from an automated air pipette system. The measured mass discrimination difference (MD) as determined by the 40Ar/36Ar ratio between the 1-fold and 5-fold air pipette shots is ~5%. The air 40Ar/36Ar aliquots were measured using a MAP 215-50 operating in pulse counting mode. The air measurements were interspersed with measurements of Alder Creek (AC) sanidine and Fish Canyon (FC) sanidine that were co-irradiated for 0.75 hours. The grain sizes for the two mineral standards were chosen such that the AC sample yielded 40Ar signals of about 50 kcps, similar to that delivered by a single aliquot delivered by the air pipette. The FC grains were about 5-10 times greater (150-600 kcps) than the single air aliquot. Following the analyses, we applied the MD correction to both the FC and AC analyses. When the MD as determined from the single pipette data (which matches 40Ar beam intensity of the AC sample) is applied to both the AC and FC data a "J" of 1.579±0.001x10-4 is obtained from the FC data and an age of 1183 ±4 ka for AC. However, when the MD as determined from the multiple aliquot pipette data (with an 40Ar beam similar to that of the FC analyses) is applied to the FC data a "J" of 1.588±0.001x10-4 is obtained and an AC age of 1189 ±4 ka the same age at the 95% confidence level, the reported age for AC. We conclude that variation in MD over signal sizes typically analyzed in 40Ar

  9. Matrix fractional systems

    NASA Astrophysics Data System (ADS)

    Tenreiro Machado, J. A.

    2015-08-01

    This paper addresses the matrix representation of dynamical systems in the perspective of fractional calculus. Fractional elements and fractional systems are interpreted under the light of the classical Cole-Cole, Davidson-Cole, and Havriliak-Negami heuristic models. Numerical simulations for an electrical circuit enlighten the results for matrix based models and high fractional orders. The conclusions clarify the distinction between fractional elements and fractional systems.

  10. Cross-sectional void fraction distribution measurements in a vertical annulus two-phase flow by high speed X-ray computed tomography and real-time neutron radiography techniques

    SciTech Connect

    Harvel, G.D. |; Hori, K.; Kawanishi, K.

    1995-09-01

    A Real-Time Neutron Radiography (RTNR) system and a high speed X-ray Computed tomography (X-CT) system are compared for measurement of two-phase flow. Each system is used to determine the flow regime, and the void fraction distribution in a vertical annulus flow channel. A standard optical video system is also used to observe the flow regime. The annulus flow channel is operated as a bubble column and measurements obtained for gas flow rates from 0.0 to 30.01/min. The flow regimes observed by all three measurement systems through image analysis shows that the two-dimensional void fraction distribution can be obtained. The X-CT system is shown to have a superior temporal resolution capable of resolving the void fraction distribution in an (r,{theta}) plane in 33.0 ms. Void fraction distribution for bubbly flow and slug flow is determined.

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

    PubMed

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

    2016-03-28

    Relative primary acoustic gas thermometry (AGT) 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 AGT 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 Kfractional 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

  12. Ab initio calculations of Li and B equilibrium isotope fractionation between high -P and -T minerals and aqueous fluids

    NASA Astrophysics Data System (ADS)

    Kowalski, P.; Jahn, S.; Wunder, B.

    2011-12-01

    Stable isotopes are excellent geochemical tracers widely used in petrology. Among them the isotopes of light elements such as Li or B strongly fractionate between minerals and aqueous fluids during fluid-rock interaction processes, which makes them excellent tracers of mass transfer processes in the subduction cycle. In order to use the full power of isotopes tracing methods the isotope fractionation mechanisms and fractionation factors between minerals and fluids of interest must be well known and characterized. One of the most important mechanisms leading to the formation of isotopic signatures is the equilibrium isotope fractionation, which nowadays can be modeled on the atomic scale by modern computational methods. However, due to high computational requirements the current works have been limited to calculations of simple materials only. In order to overcome these limitations we develop an efficient ab initio based computational approach for prediction of the equilibrium isotope fractionation factors between high pressure and temperature materials, including fluids, which would allow for efficient calculations of the isotope fractionation factors of complex minerals and fluids containing even hundreds of atoms in the supercell. We will show our results for the Li and B stable equilibrium isotope fractionation factors between complex Li/B-bearing crystalline solids (staurolite, spodumene, tourmaline, olenite and micas) and aqueous fluids. The fractionation factors were obtained in an efficient way by simplifying the consideration to calculations of the properties of fractionating atoms only. The comparison of the calculated fractionation factors, on the qualitative and quantitative levels, with the existing experimental data show the comparable to the in situ experimental techniques, predictive power of the computations. We show that with the atomistic scale modelling we are able to reproduce correctly the experimental isotope fractionation sequences

  13. [Effect of SO2 volume fraction in flue gas on the adsorption behaviors adsorbed by ZL50 activated carbon and kinetic analysis].

    PubMed

    Gao, Ji-xian; Wang, Tie-feng; Wang, Jin-fu

    2010-05-01

    The influence of SO2 dynamic adsorption behaviors using ZL50 activated carbon for flue gas desulphurization and denitrification under different SO2 volume fraction was investigated experimentally, and the kinetic analysis was conducted by kinetic models. With the increase of SO2 volume fraction in flue gas, the SO2 removal ratio and the activity ratio of ZL50 activated carbon decreased, respectively, and SO2 adsorption rate and capacity increased correspondingly. The calculated results indicate that Bangham model has the best prediction effect, the chemisorption processes of SO2 was significantly affected by catalytic oxidative reaction. The adsorption rate constant of Lagergren's pseudo first order model increased with the increase of inlet SO, volume fraction, which indicated that catalytic oxidative reaction of SO2 adsorbed by ZL50 activated carbon may be the rate controlling step in earlier adsorption stage. The Lagergren's and Bangham's initial adsorption rate were deduced and defined, respectively. The Ho's and Elovich's initial adsorption rate were also deduced in this paper. The Bangham's initial adsorption rate values were defined in good agreement with those of experiments. The defined Bangham's adsorptive reaction kinetic model can describe the SO2 dynamic adsorption rate well. The studied results indicated that the SO2 partial order of initial reaction rate was one or adjacent to one, while the O2 and water vapor partial order of initial reaction rate were constants ranging from 0.15-0.20 and 0.45-0.50, respectively.

  14. 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.

  15. Highly sensitive Raman system for dissolved gas analysis in water.

    PubMed

    Yang, Dewang; Guo, Jinjia; Liu, Qingsheng; Luo, Zhao; Yan, Jingwen; Zheng, Ronger

    2016-09-20

    The detection of dissolved gases in seawater plays an important role in ocean observation and exploration. As a potential technique for oceanic applications, Raman spectroscopy has already proved its advantages in the simultaneous detection of multiple species during previous deep-sea explorations. Due to the low sensitivity of conventional Raman measurements, there have been many reports of Raman applications on direct seawater detection in high-concentration areas, but few on undersea dissolved gas detection. In this work, we have presented a highly sensitive Raman spectroscopy (HSRS) system with a special designed gas chamber for small amounts of underwater gas extraction. Systematic experiments have been carried out for system evaluation, and the results have shown that the Raman signals obtained by the innovation of a near-concentric cavity was about 21 times stronger than those of conventional side-scattering Raman measurements. Based on this system, we have achieved a low limit of detection of 2.32 and 0.44  μmol/L for CO2 and CH4, respectively, in the lab. A test-out experiment has also been accomplished with a gas-liquid separator coupled to the Raman system, and signals of O2 and CO2 were detected after 1 h of degasification. This system may show potential for gas detection in water, and further work would be done for the improvement of in situ detection.

  16. Highly sensitive Raman system for dissolved gas analysis in water.

    PubMed

    Yang, Dewang; Guo, Jinjia; Liu, Qingsheng; Luo, Zhao; Yan, Jingwen; Zheng, Ronger

    2016-09-20

    The detection of dissolved gases in seawater plays an important role in ocean observation and exploration. As a potential technique for oceanic applications, Raman spectroscopy has already proved its advantages in the simultaneous detection of multiple species during previous deep-sea explorations. Due to the low sensitivity of conventional Raman measurements, there have been many reports of Raman applications on direct seawater detection in high-concentration areas, but few on undersea dissolved gas detection. In this work, we have presented a highly sensitive Raman spectroscopy (HSRS) system with a special designed gas chamber for small amounts of underwater gas extraction. Systematic experiments have been carried out for system evaluation, and the results have shown that the Raman signals obtained by the innovation of a near-concentric cavity was about 21 times stronger than those of conventional side-scattering Raman measurements. Based on this system, we have achieved a low limit of detection of 2.32 and 0.44  μmol/L for CO2 and CH4, respectively, in the lab. A test-out experiment has also been accomplished with a gas-liquid separator coupled to the Raman system, and signals of O2 and CO2 were detected after 1 h of degasification. This system may show potential for gas detection in water, and further work would be done for the improvement of in situ detection. PMID:27661606

  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. 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.

  19. Microstructural development in high volume fraction gamma prime Ni-base oxide-dispersion-strengthened superalloys

    NASA Astrophysics Data System (ADS)

    Kang, S. K.; Benn, R. C.

    1985-07-01

    The mechanical alloying process has successfully combined oxide-dispersion-strengthening with conventional gamma prime precipitation hardening for advanced gas turbine materials. INCONEL* alloy MA 6000, a mechanically alloyed Ni-base superalloy, has the highest temperature capability among commercially available superalloys. Further improvement of the intermediate temperature strength has been pursued by both increasing the gamma prime content up to 80 vol pct and controlling the additions of refractory metals. The microstructural development of these new experimental alloys is reported in this paper, especially for an alloy, nominally identified as Alloy 51, having the composition Ni-9.3 pct Cr-8.5 pct Al-6.6 pct W-3.4 pct Mo-0.15 pct Zr-0.01 pct B-l.l pct Y2O3 (wt pct). Both the primary and the secondary recrystallized microstructures of the alloy were characterized in terms of gamma grain structure, gamma prime precipitate morphology, orientation relationships, dispersoids, carbide/nitride particles, and chemical composition of intermetallic phases. The microstructural stability of the alloy under stress rupture conditions was also investigated in terms of coarsening/coalescence of gamma prime precipitates. Correlation of the microstructural information with the high temperature properties of the alloy is also briefly discussed.

  20. Effect of Non-Condensable Gas Mass Fraction on Condensation Heat Transfer for Water-Ethanol Vapor Mixture

    NASA Astrophysics Data System (ADS)

    Wang, Shixue; Utaka, Yoshio

    The condensation heat transfer characteristic curves for a ternary vapor mixture of water, ethanol and air (or nitrogen) under several ethanol concentrations and relatively low concentrations of air (or nitrogen) were measured. The effect of non-condensable gas on several different domains in the condensation curves was discussed. The effect of non-condensable gas in the domains controlled by the diffusion resistance and the filmwise condensation was not notable; whereas that in the domain dominated by the condensate resistance of dropwise mode was remarkable. Moreover, variations due to changes in non-condensable gas concentration of several characteristic points representing the curves were discussed.

  1. Antiedematogenic and antioxidant properties of high molecular weight protein sub-fraction of Calotropis procera latex in rat

    PubMed Central

    Chaudhary, Priyanka; de Araújo Viana, Carolina; Ramos, Marcio V.; Kumar, Vijay L.

    2015-01-01

    Objectives: The aim was to evaluate the effect of high molecular weight protein fraction of Calotropis procera latex on edema formation and oxidative stress in carrageenan-induced paw inflammation. Methods: A sub-plantar injection of carrageenan was given to induce edema in the hind paw of the rat. The inhibitory effect of high molecular weight protein fraction of C. procera latex was evaluated following intravenous administration (5 and 25 mg/kg body weight) and was compared with that of diclofenac given orally (5 mg/kg). The levels of reduced glutathione (GSH), thiobarbituric acid reactive substances (TBARS) and myeloperoxidase (MPO) were measured in the inflamed paw tissue at the end of the study. Results: The high molecular weight protein fraction obtained from the latex of C. procera produced a dose-dependent inhibition of edema formation that was accompanied by normalization of levels of oxidative stress markers (GSH and TBARS) and MPO, a marker for neutrophils in the paw tissue. Conclusions: The high molecular weight protein fraction of C. procera latex ameliorates acute inflammation in the paw through its antioxidant effect. PMID:25767367

  2. 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.

  3. 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.

  4. 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.

  5. 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. PMID:25902973

  6. Aperture synthesis mapping of molecular gas in high-luminosity IRAS galaxies

    NASA Technical Reports Server (NTRS)

    Sanders, D. B.; Soifer, B. T.; Scoville, N. Z.; Sargent, A. I.

    1988-01-01

    The Owens Valley millimeter-wave interferometer has been used for high-resolution mapping of the 2.6 mm CO emission from the high-luminosity infrared galaxies NGC 520 (Arp 157), NGC 7469 (Arp 298), and Arp 55. Assuming the same empirical relationship between CO brightness and molecular hydrogen surface mass density as has been found for giant molecular clouds in the Milky Way, it is found that the masses of H2 gas in these concentrations are 10 to the 9th - 10 to the 10th solar masses, typically one-third of the total molecular gas content of these galaxies. The interferometric sizes correspond to radii of 0.8 kpc (NGC 520), 1.4 kpc (NGC 7469), and less than 2.8 kpc (Arp 55). For the same regions the dynamical masses estimated from the CO line width and size of the emission region are only a factor of 3-5 higher. The mean molecular gas surface densities averaged over these regions are in the range 610-825 solar masses/sq pc, a factor of 10 brighter than those obtained for corresponding regions in the nucleus of the Milky Way. The high mass fractions obtained for the interstellar medium in the central regions of these three galaxies strongly suggest that large-scale gravitational instability in the gas may play an important role in the further concentration of the gas in the nucleus and in possibly precipitating a large-scale burst of star formation.

  7. High resolution 3D gas-jet characterization

    SciTech Connect

    Landgraf, Bjoern; Kaluza, Malte C.; Spielmann, Christian; Schnell, Michael; Saevert, Alexander

    2011-08-15

    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 {mu}m for an Argon density as low as 2 x 10{sup 17} cm{sup -3}.

  8. 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.

  9. 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.

  10. A multi-channel gel electrophoresis and continuous fraction collection apparatus for high throughput protein separation and characterization

    SciTech Connect

    Choi, Megan; Nordmeyer, Robert A.; Cornell, Earl; Dong, Ming; Biggin, Mark D.; Jin, Jian

    2009-10-02

    To facilitate a direct interface between protein separation by PAGE and protein identification by mass spectrometry, we developed a multichannel system that continuously collects fractions as protein bands migrate off the bottom of gel electrophoresis columns. The device was constructed using several short linear gel columns, each of a different percent acrylamide, to achieve a separation power similar to that of a long gradient gel. A Counter Free-Flow elution technique then allows continuous and simultaneous fraction collection from multiple channels at low cost. We demonstrate that rapid, high-resolution separation of a complex protein mixture can be achieved on this system using SDS-PAGE. In a 2.5 h electrophoresis run, for example, each sample was separated and eluted into 48-96 fractions over a mass range of 10-150 kDa; sample recovery rates were 50percent or higher; each channel was loaded with up to 0.3 mg of protein in 0.4 mL; and a purified band was eluted in two to three fractions (200 L/fraction). Similar results were obtained when running native gel electrophoresis, but protein aggregation limited the loading capacity to about 50 g per channel and reduced resolution.

  11. 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.

  12. Comparison of three sequential extraction procedures for fractionation of arsenic from highly polluted mining sediments.

    PubMed

    Larios, Raquel; Fernández-Martínez, Rodolfo; Rucandio, Isabel

    2012-03-01

    Three sequential extraction procedures were evaluated for the study of fractionation of arsenic in environmental solid samples. The procedures considered were as follows: i) the standardized and widely recognised BCR procedure, conceived for the study of the partitioning of heavy metals; ii) the procedure developed by Manful, who adapted a phosphorus scheme for arsenic fractionation; and iii) a novel sequential extraction scheme especially devised for arsenic. The efficiency and suitability of these methods and the corresponding extraction steps for partitioning arsenic obtained from the most important solid forms were tested by application of the methods to real sediment samples heavily polluted by mining activity. Results showed the BCR scheme was inappropriate for arsenic fractionation. The procedure could, nevertheless, be a first approach for the assessment of arsenic partitioning, because its first extraction step can be regarded as adequate for the estimation of the most easily mobilizable arsenic. Although the Manful scheme results in a more differentiated arsenic pattern, some drawbacks arise from the lack of selectivity of some of the reagents used, for example overlapping of specific target phases, overestimation of adsorbed arsenate because of inadequate coprecipitation processes, and the inability to discriminate among amorphous and crystalline oxyhydroxides which are mainly responsible for arsenic retention. The novel procedure achieves the most suitable arsenic fractionation, because the main phases retaining arsenic are selectively targeted according to mobilization potential. In addition, the simplicity of its extraction steps would enable automation in a continuous flow scheme.

  13. Molecular Gas in Starburts ARP 220 & NGC 6240: Understanding Mergers using High Density Gas Tracers

    NASA Astrophysics Data System (ADS)

    Manohar, Swarnima; Scoville, Nicholas; Sheth, Kartik

    2015-01-01

    NGC 6240 and Arp 220 can be considered the founding members of a very active class of objects called Ultraluminous Infrared Galaxies or ULIRGs. They are in different stages of mergers and hence are excellent case studies to enhance our knowledge about the merging process. We have imaged the dense star-forming regions of these galaxies at sub-arcsec resolution with ALMA and CARMA. Multi-band imaging allows multilevel excitation analysis of HCN, HCO+ and CS transitions which will constrain the properties of the gas as a function of position and velocity (across line profiles). We are doing an extensive multilevel excitation analysis of the merger as a function of radius which enables in depth understanding of the gas dynamics and gas properties such as temperature and density. This in turn probes the homogeneity of the gas in the merging system and hence the regions that facilitate high star formation rates. This tandem use of CARMA with ALMA to map these systems at different merger stages will assemble a more integrated picture of the merger process. We are probing the distribution and dynamics of star forming gas and star formation activity in the dense disk structures to enable new theoretical understanding of the physics, dynamics, star formation activity and associated feedback in the most active and rapidly evolving galactic nuclei. Here we present our observations of Arp 220 and NGC 6240 from ALMA and CARMA.

  14. Molecular Gas in Local Mergers: Understanding Mergers using High Density Gas Tracers

    NASA Astrophysics Data System (ADS)

    Manohar, Swarnima; Scoville, N.; Sheth, K.

    2013-01-01

    NGC 6240 and Arp 220 can be considered the founding members of a very active class of objects called Ultraluminous Infrared Galaxies or ULIRGs. They are in different stages of mergers and hence are excellent case studies to enhance our knowledge about the merging process. We have imaged the dense star-forming regions of these galaxies at sub-arcsec resolution with ALMA and CARMA. Multi-band imaging will allow multilevel excitation analysis of HCN, HCO+ and CS transitions which will be used to constrain the properties of the gas as a function of position and velocity (across line profiles). We aim to do an extensive multilevel excitation analysis of the merger as a function of radius which will enable in depth understanding of the gas dynamics and gas properties such as temperature and density. This will in turn probe the homogeneity of the gas in the merging system and hence the regions that facilitate high star formation rates. This tandem use of CARMA with ALMA to map these systems at different merger stages will help assemble a more integrated picture of the merger process. We will probe the distribution and dynamics of star forming gas and star formation activity in the dense disk structures to enable new theoretical understanding of the physics, dynamics, star formation activity and associated feedback in the most active and rapidly evolving galactic nuclei. Here we present preliminary observations of Arp 220 and NGC 6240 from ALMA and CARMA.

  15. Molecular Gas in Starburts: Understanding Mergers using High Density Gas Tracers

    NASA Astrophysics Data System (ADS)

    Manohar, Swarnima; Scoville, N.; Walter, F.; Sheth, K.

    2014-01-01

    NGC 6240 and Arp 220 can be considered the founding members of a very active class of objects called Ultraluminous Infrared Galaxies or ULIRGs. They are in different stages of mergers and hence are excellent case studies to enhance our knowledge about the merging process. We have imaged the dense star-forming regions of these galaxies at sub-arcsec resolution with ALMA and CARMA. Multi-band imaging allows multilevel excitation analysis of HCN, HCO+ and CS transitions which will constrain the properties of the gas as a function of position and velocity (across line profiles). We are doing an extensive multilevel excitation analysis of the merger as a function of radius which enables in depth understanding of the gas dynamics and gas properties such as temperature and density. This in turn probes the homogeneity of the gas in the merging system and hence the regions that facilitate high star formation rates. This tandem use of CARMA with ALMA to map these systems at different merger stages will assemble a more integrated picture of the merger process. We are probing the distribution and dynamics of star forming gas and star formation activity in the dense disk structures to enable new theoretical understanding of the physics, dynamics, star formation activity and associated feedback in the most active and rapidly evolving galactic nuclei. Here we present preliminary observations of Arp 220 and NGC 6240 from ALMA and CARMA.

  16. Retrieving Cloud Fraction in the Field-of-View of a High-Spectral Resolution Infrared Radiometer

    SciTech Connect

    Turner, David D.; Holz, R. E.

    2005-07-01

    The combination of radiance from both clear and cloudy regions of sky adds significant uncertainty to retrievals of atmospheric state profiles and cloud microphysical properties from infrared radiometers. In this article, we use observations of radiance from both the 8-13 μm and 3-5 μm bands to retrieve estimates of the cloud fraction in the field-of-view, as well as microphysical cloud The combination of radiance from both clear and cloudy regions of sky adds significant uncertainty to retrievals of atmospheric state profiles and cloud microphysical properties from infrared radiometers. In this article, we use observations of radiance from both the 8-13 μm and 3-5 μm bands to retrieve estimates of the cloud fraction in the field-of-view, as well as microphysical cloud properties, from high-spectral-resolution infrared radiometers. Cloud fraction derived from imagers as well as high-time-resolution observations show good agreement and high correlation with our derived cloud fraction values. This is shown for both ground-based and aircraft based observations. We also demonstrate that the use of the addition information in the 3-5 μm band extends the dynamic range and accuracy of microphysical properties that can be retrieved from infrared radiance data.

  17. 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.

  18. Experimental study of high-Z gas buffers in gas-filled ICF engines

    NASA Astrophysics Data System (ADS)

    Rhodes, M. A.; Kane, J.; Loosmore, G.; DeMuth, J.; Latkowski, J.

    2011-03-01

    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.

  19. 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.

  20. Bubble growth by rectified diffusion at high gas supersaturation levels.

    PubMed

    Ilinskii, Yurii A; Wilson, Preston S; Hamilton, Mark F

    2008-10-01

    For high gas supersaturation levels in liquids, on the order of 300% as predicted in capillaries of marine mammals following a series of dives [D. S. Houser, R. Howard, and S. Ridgway, J. Theor. Biol. 213, 183-195 (2001)], standard mathematical models of both static and rectified diffusion are found to underestimate the rate of bubble growth by 10%-20%. The discrepancy is demonstrated by comparing predictions based on existing mathematical models with direct numerical solutions of the differential equations for gas diffusion in the liquid and thermal conditions in the bubble. Underestimation of bubble growth by existing mathematical models is due to the underlying assumption that the gas concentration in the liquid is given by its value for a bubble of constant equilibrium radius. This assumption is violated when high supersaturation causes the bubble to grow too fast in relation to the time scale associated with diffusion. Rapid bubble growth results in an increased gas concentration gradient at the bubble wall and therefore a growth rate in excess of predictions based on constant equilibrium bubble radius.

  1. Bubble growth by rectified diffusion at high gas supersaturation levels.

    PubMed

    Ilinskii, Yurii A; Wilson, Preston S; Hamilton, Mark F

    2008-10-01

    For high gas supersaturation levels in liquids, on the order of 300% as predicted in capillaries of marine mammals following a series of dives [D. S. Houser, R. Howard, and S. Ridgway, J. Theor. Biol. 213, 183-195 (2001)], standard mathematical models of both static and rectified diffusion are found to underestimate the rate of bubble growth by 10%-20%. The discrepancy is demonstrated by comparing predictions based on existing mathematical models with direct numerical solutions of the differential equations for gas diffusion in the liquid and thermal conditions in the bubble. Underestimation of bubble growth by existing mathematical models is due to the underlying assumption that the gas concentration in the liquid is given by its value for a bubble of constant equilibrium radius. This assumption is violated when high supersaturation causes the bubble to grow too fast in relation to the time scale associated with diffusion. Rapid bubble growth results in an increased gas concentration gradient at the bubble wall and therefore a growth rate in excess of predictions based on constant equilibrium bubble radius. PMID:19062834

  2. 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)

  3. Multi-channel open tubular traps for headspace sampling, gas chromatographic fraction collection and olfactory assessment of milk volatiles.

    PubMed

    Naudé, Yvette; van Aardt, Marleen; Rohwer, Egmont Richard

    2009-04-01

    A headspace sampling method is described for concentrating milk volatiles onto a multi-channel open tubular silicone rubber trap (MCT) for thermal desorption into a GC-FID. Sections of the chromatographic profile, single peaks or combinations of compounds are recaptured with secondary MCTs during a subsequent run. The recaptured aroma is released in a controlled manner by heating the MCT in a portable heating device. An aroma release window of several minutes allows up to six people the opportunity to sniff each aroma fraction more than once. Olfactory results suggest that a synergistic combination of 2-heptanone and 2-nonanone could be responsible for a pungent cheese, sour milk-like aroma. MCTs containing single components or fractions can be desorbed into a GC-MS for compound identification.

  4. Experimental determination of Fe isotope fractionation between liquid metal, silicate and sulfide at high pressures and temperatures

    NASA Astrophysics Data System (ADS)

    Williams, H. M.; Wood, B. J.; Halliday, A. N.

    2007-12-01

    There is evidence for significant equilibrium Fe isotope fractionation (≤0.26‰/amu) between metal and troilite (FeS) in iron meteorites (Williams et al., EPSL (250) 2006) and a smaller fractionation (<0.1‰/amu) between metal and olivine in pallasites (Zhu et al., EPSL (200) 2002; Weyer et al., EPSL (240) 2005). Theory suggests that differences in iron oxidation state and coordination between metal, silicate and FeS will result in stable isotope fractionation (Polyakov and Mineev, GCA (64) 2000; Schauble et al., GCA (65) 2001). However, it is not yet clear if the apparent observed fractionations can be extrapolated to the pressure and temperature conditions of planetary core formation. We have investigated Fe isotope fractionation between silicate melt and liquid Fe-S alloys and between liquid iron and basaltic melt at pressure and temperature conditions of 2-2.5GPa and 1920-2150K using piston-cylinder partitioning experiments from previous studies (Kilburn and Wood EPSL (152) 1997; Gessmann and Wood, EPSL (200) 2002; Wood et al., EPSL (in revision) 2007). Metal, sulfide and silicate fractions were separated from mounted and sectioned experimental charges using a computer-controlled micromill (New Wave-Merchantek). Sample dissolution, Fe purification and isotopic analysis followed established procedures (Williams et al., EPSL (235) 2005). In agreement with another preliminary high-pressure experimental study (Poitrasson and Roskosz, LPSC XXXVIII 2007) we find no appreciable fractionation between liquid iron metal and basaltic melt. However, there is a resolvable Fe isotope fractionation between silicate melt and Fe-S alloy which ranges from 0.12±0.04 to 0.15±0.04‰/amu for separate experiments (errors are propagated based on the 2 SD errors of replicate analyses). The Fe isotope compositions of coexisting phases from these experiments define a positive linear relationship with a slope that is, within error, equal to unity, implying isotopic equilibrium. No

  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. High temperature alkali corrosion of ceramics in coal gas

    SciTech Connect

    Pickrell, G.R.; Sun, T.; Brown, J.J.

    1992-05-27

    High temperature alkali corrosion has been known to cause premature failure of ceramic components used in advanced high temperature coal combustion systems such as coal gasification and clean-up, coal fired gas turbines, and high efficiency heat engines. The objective of this research is to systematically evaluate the alkali corrosion resistance of the most commonly used structural ceramics including silicon carbide, silicon nitride, cordierite, mullite, alumina, aluminum titanate, zirconia, and fireclay glass. The study consists of identification of the alkali reaction products (phase equilibria) and the kinetics of the alkali reactions as a function of temperature and time.

  7. High temperature alkali corrosion of ceramics in coal gas

    SciTech Connect

    Pickrell, G.R.; Sun, T.; Brown, J.J.

    1991-11-30

    High temperature alkali corrosion has been known to cause premature failure of ceramic components used in advanced high temperature coal combustion systems such as coal gasification and clean-up, coal fired gas turbines, and high efficiency heat engines. The objective of this program is to systematically evaluate the alkali corrosion resistance of the most commonly used structural ceramics including silicon carbide, silicon nitride, cordierite, mullite, alumina, aluminum titanate, zirconia, and fireclay glass. The study consists of identification of the alkali reaction products (phase equilibria) and the kinetics of the alkali reactions as a function of temperature and time.

  8. High temperature alkali corrosion of ceramics in coal gas

    SciTech Connect

    Pickrell, G.R.; Sun, T.; Brown, J.J.

    1992-08-29

    High temperature alkali corrosion has been known to cause premature failure of ceramic components used in advanced high temperature coal combustion systems such as coal gasification and clean-up, coal fired gas turbines, and high efficiency heat engines. The objective of this research is to systematically evaluate the alkali corrosion resistance of the most commonly used structural ceramics including silicon carbide, silicon nitride, cordierite, mullite, alumina, aluminum titanate, zirconia, and fireclay glass. The study consists of identification of the alkali reaction products (phase equilibria) and the kinetics of the alkali reactions as a function of temperature and time.

  9. 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.

  10. Flow and Geometry Control the Onset of Jamming in Fractures with High Solid-Fraction Fluids

    NASA Astrophysics Data System (ADS)

    Medina, R.; Elkhoury, J. E.; Shannon, L. J.; Detwiler, R. L.; Morris, J.; Prioul, R.; Desroches, J.

    2013-12-01

    Fluids containing a large fraction of suspended solids are common in the subsurface. Examples include fluids used for environmental remediation, hydraulic fracturing fluids and magma. These fluid-solid mixtures behave as non-Newtonian fluids where interactions between fluid, suspended solids, and pore walls can lead to jamming of the suspended solids. Jamming causes the velocity of the solid to decrease locally to zero causing a rapid decrease in permeability as the fluid is forced to flow through the pore space within the immobilized solid. Here we present results from experiments that quantify the flow of non-Newtonian suspensions in an analog parallel-plate fracture (transparent 15cm x 15cm with ~3-mm aperture) and explore the dependence of jamming on flow conditions, fracture geometry, and the action of gravity. We used guar gum mixed with water (0.75%) as the fluid and added 50% by volume of crushed silica (< 300μm). Flow rates ranged from 0.2ml/min to 6.0ml/min, cell orientation varied from horizontal to vertical (bottom to top) flow and a transducer provided continuous measurement of differential pressure across the cell. A strobed LED panel backlit the cell and a high-resolution CCD camera captured frequent (0.2 Hz) images during all experiments. Particle image velocimetry (PIV) yielded measurements of the evolving velocity field during experiments (see Figure). In the vertical orientation during the initial period of high flow rate, outflow decreased rapidly and the differential pressure increased indicating jamming within the cell. Subsequent efforts to flush solids from the cell suggested that jamming occurred at the inlet of the cell. This was likely due to settling of solids within the flow field indicating that the time scale associated with settling was shorter than the time scale of advection through the cell. In the horizontal orientation, localized jamming occurred at the lowest flow rate in a region near the outlet. This suggests that when

  11. Gas-pressure dependence of charge-state fractions and mean charges of 1.4 MeV/u-uranium ions stripped in molecular hydrogen

    NASA Astrophysics Data System (ADS)

    Shevelko, V. P.; Winckler, N.; Tolstikhina, I. Yu.

    2016-06-01

    Using a recently created BREIT computer code (Balance Rate Equations for Ion Transportation), evolutions of the charge-state fractions Fq (x) and equilibrium mean charge states q bar are calculated for stripping of 1.4 MeV/u-U4+ ions in H2 gas for target thicknesses x ⩽ 100 μg /cm2 (⩽ 3 ·1019molecule /cm2) and gas pressures 10-4 ⩽ P ⩽ 500 mbar. Calculations of the non-equilibrium Fq (x) and equilibrium Fq0 distributions for ion charges 4 ⩽ q ⩽ 40 are performed by solving the balance (rate) equations with account for the multi-electron processes and the target-density effect. Calculated equilibrium mean charge state increases from q bar ≈ 27.6 at P =10-4 mbar to its saturated (maximum) value of q bar ≈ 32.7 at pressures P≳ 250 mbar while the equilibrium target thickness xeq increases from 20 to 50 μg /cm2 (from 0.6 to 1.5 in units of 1019molecule /cm2) in the H2-pressure range considered. From the present calculations it is concluded that the maximum mean charge state q bar which can be achieved in stripping of 1.4 MeV/u-U4+ ions in H2 gas is about q bar ≈ 33 at a gas pressure P≳ 250 mbar.

  12. Antioxidant activity of fractionated extracts of rhizomes of high-altitude Podophyllum hexandrum: role in radiation protection.

    PubMed

    Chawla, Raman; Arora, Rajesh; Kumar, Raj; Sharma, Ashok; Prasad, Jagdish; Singh, Surendar; Sagar, Ravinder; Chaudhary, Pankaj; Shukla, Sandeep; Kaur, Gurpreet; Sharma, Rakesh Kumar; Puri, Satish Chander; Dhar, Kanaya Lal; Handa, Geeta; Gupta, Vinay Kumar; Qazi, Ghulam Nabi

    2005-05-01

    Whole extract of rhizomes of Podophyllum hexandrum has been reported earlier by our group to render whole-body radioprotection. High-altitude P. hexandrum (HAPH) was therefore fractionated using solvents of varying polarity (non-polar to polar) and the different fractions were designated as, n-hexane (HE), chloroform (CE), alcohol (AE), hydro-alcohol (HA) and water (WE). The total polyphenolic content (mg% of quercetin) was determined spectrophotometrically, while. The major constituents present in each fraction were identified and characterized using LC-APCI/MS/MS. In vitro screening of the individual fractions, rich in polyphenols and lignans, revealed several bioactivities of direct relevance to radioprotection e.g. metal-chelation activity, antioxidant activity, DNA protection, inhibition of radiation (250 Gy) and iron/ascorbate-induced lipid peroxidation (LPO). CE exhibited maximum protection to plasmid (pBR322) DNA in the plasmid relaxation assay (68.09% of SC form retention). It also showed maximal metal chelation activity (41.59%), evaluated using 2,2'-bipyridyl assay, followed by AE (31.25%), which exhibited maximum antioxidant potential (lowest absorption unit value: 0.0389 +/- 0.00717) in the reducing power assay. AE also maximally inhibited iron/ascorbate-induced and radiation-induced LPO (99.76 and 92.249%, respectively, at 2000 microg/ml) in mouse liver homogenate. Under conditions of combined stress (radiation (250 Gy) + iron/ascorbate), at a concentration of 2000 microg/ml, HA exhibited higher percentage of inhibition (93.05%) of LPO activity. HA was found to be effective in significantly (p < 0.05) lowering LPO activity over a wide range of concentrations as compared to AE. The present comparative study indicated that alcoholic (AE) and hydro-alcoholic (HA) fractions are the most promising fractions, which can effectively tackle radiation-induced oxidative stress.

  13. 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.

  14. Geothermal well stimulated using High Energy Gas Fracturing

    SciTech Connect

    Chu, T.Y.; Jacobson, R.D.; Warpinski, N.; Mohaupt, H.

    1987-01-01

    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.

  15. 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.

  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. Gas transport in branched airways during high-frequency ventilation.

    PubMed

    Scherer, P W; Haselton, F R; Seybert, J R

    1984-01-01

    A theoretical model of high-frequency ventilation (HFV) is presented based on the physical convective exchange process that occurs due to the irreversibility of gas velocity profiles in oscillatory flow through the bronchial airways. Mass transport during the convective exchange process can be characterized by a convective exchange length, LE, which depends only on the irreversibility of bronchial velocity profiles and can be measured by the experimental technique of photographic flow visualization in bronchial tree models. Using the exchange length and the molecular diffusivity, a simple model of overall bronchial mass transfer is developed. The model allows a prediction of the mean gas concentration profiles along the airways, the site of maximum mass transfer resistance, and overall flow rate of the gas of interest in or out of the lung as functions of the parameters of HFV. The results predicted by the model agree with the limited experimental data available for animals and humans. For normal unassisted ventilation, total bronchial cross-sectional area around the 15th Weibel bronchial generation is predicted to be the single most important parameter in controlling the total gas transport rate along the airways. For the breathing of room air, values of the respiratory quotient around 0.78 are predicted, which are insensitive to VT and f. The model represents a fruitful combination of fluid mechanical theory and experiment with physiologic data to yield new and deeper insight into the operation of the human respiratory system during HFV and normal breathing.

  18. 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

  19. Zinc Isotope Fractionation in the Hyperaccumulator Noccaea caerulescens and the Nonaccumulating Plant Thlaspi arvense at Low and High Zn Supply.

    PubMed

    Tang, Ye-Tao; Cloquet, Christophe; Deng, Teng-Hao-Bo; Sterckeman, Thibault; Echevarria, Guillaume; Yang, Wen-Jun; Morel, Jean-Louis; Qiu, Rong-Liang

    2016-08-01

    On the basis of our previous field survey, we postulate that the pattern and degree of zinc (Zn) isotope fractionation in the Zn hyperaccumulator Noccaea caerulescens (J. & C. Presl) F. K. Mey may reflect a relationship between Zn bioavailability and plant uptake strategies. Here, we investigated Zn isotope discrimination during Zn uptake and translocation in N. caerulescens and in a nonaccumulator Thlaspi arvense L. with a contrasting Zn accumulation ability in response to low (Zn-L) and high (Zn-H) Zn supplies. The average isotope fractionations of the N. caerulescens plant as a whole, relative to solution (Δ(66)Znplant-solution), were -0.06 and -0.12‰ at Zn-L-C and Zn-H-C, respectively, indicative of the predominance of a high-affinity (e.g., ZIP transporter proteins) transport across the root cell membrane. For T. arvense, plants were more enriched in light isotopes under Zn-H-A (Δ(66)Znplant-solution = -0.26‰) than under Zn-L-A and N. caerulescens plants, implying that a low-affinity (e.g., ion channel) transport might begin to function in the nonaccumulating plants when external Zn supply increases. Within the root tissues of both species, the apoplast fractions retained up to 30% of Zn mass under Zn-H. Moreover, the highest δ(66)Zn (0.75‰-0.86‰) was found in tightly bound apoplastic Zn, pointing to the strong sequestration in roots (e.g., binding to high-affinity ligands/precipitation with phosphate) when plants suffer from high Zn stress. During translocation, the magnitude of isotope fractionation was significantly greater at Zn-H (Δ(66)Znroot-shoot = 0.79‰) than at Zn-L, indicating that fractionation mechanisms associated with root-shoot translocation might be identical to the two plant species. Hence, we clearly demonstrated that Zn isotope fractionation could provide insight into the internal sequestration mechanisms of roots when plants respond to low and high Zn supplies.

  20. Zinc Isotope Fractionation in the Hyperaccumulator Noccaea caerulescens and the Nonaccumulating Plant Thlaspi arvense at Low and High Zn Supply.

    PubMed

    Tang, Ye-Tao; Cloquet, Christophe; Deng, Teng-Hao-Bo; Sterckeman, Thibault; Echevarria, Guillaume; Yang, Wen-Jun; Morel, Jean-Louis; Qiu, Rong-Liang

    2016-08-01

    On the basis of our previous field survey, we postulate that the pattern and degree of zinc (Zn) isotope fractionation in the Zn hyperaccumulator Noccaea caerulescens (J. & C. Presl) F. K. Mey may reflect a relationship between Zn bioavailability and plant uptake strategies. Here, we investigated Zn isotope discrimination during Zn uptake and translocation in N. caerulescens and in a nonaccumulator Thlaspi arvense L. with a contrasting Zn accumulation ability in response to low (Zn-L) and high (Zn-H) Zn supplies. The average isotope fractionations of the N. caerulescens plant as a whole, relative to solution (Δ(66)Znplant-solution), were -0.06 and -0.12‰ at Zn-L-C and Zn-H-C, respectively, indicative of the predominance of a high-affinity (e.g., ZIP transporter proteins) transport across the root cell membrane. For T. arvense, plants were more enriched in light isotopes under Zn-H-A (Δ(66)Znplant-solution = -0.26‰) than under Zn-L-A and N. caerulescens plants, implying that a low-affinity (e.g., ion channel) transport might begin to function in the nonaccumulating plants when external Zn supply increases. Within the root tissues of both species, the apoplast fractions retained up to 30% of Zn mass under Zn-H. Moreover, the highest δ(66)Zn (0.75‰-0.86‰) was found in tightly bound apoplastic Zn, pointing to the strong sequestration in roots (e.g., binding to high-affinity ligands/precipitation with phosphate) when plants suffer from high Zn stress. During translocation, the magnitude of isotope fractionation was significantly greater at Zn-H (Δ(66)Znroot-shoot = 0.79‰) than at Zn-L, indicating that fractionation mechanisms associated with root-shoot translocation might be identical to the two plant species. Hence, we clearly demonstrated that Zn isotope fractionation could provide insight into the internal sequestration mechanisms of roots when plants respond to low and high Zn supplies. PMID:27359107

  1. High-Resolution Spectroscopy of Extremely Metal-Poor Stars from SDSS/SEGUE. II. Binary Fraction

    NASA Astrophysics Data System (ADS)

    Aoki, Wako; Suda, Takuma; Beers, Timothy C.; Honda, Satoshi

    2015-02-01

    The fraction of binary systems in various stellar populations of the Galaxy and the distribution of their orbital parameters are important but not well-determined factors in studies of star formation, stellar evolution, and Galactic chemical evolution. While observational studies have been carried out for a large sample of nearby stars, including some metal-poor Population II stars, almost no constraints on the binary nature for extremely metal-poor (EMP; [Fe/H] \\lt -3.0) stars have yet been obtained. Here we investigate the fraction of double-lined spectroscopic binaries and carbon-enhanced metal-poor (CEMP) stars, many of which could have formed as pairs of low-mass and intermediate-mass stars, to estimate the lower limit of the fraction of binary systems having short periods. The estimate is based on a sample of very metal-poor stars selected from the Sloan Digital Sky Survey and observed at high spectral resolution in a previous study by Aoki et al. That survey reported 3 double-lined spectroscopic binaries and 11 CEMP stars, which we consider along with a sample of EMP stars from the literature compiled in the SAGA database. We have conducted measurements of the velocity components for stacked absorption features of different spectral lines for each double-lined spectroscopic binary. Our estimate indicates that the fraction of binary stars having orbital periods shorter than 1000 days is at least 10%, and possibly as high as 20% if the majority of CEMP stars are formed in such short-period binaries. This result suggests that the period distribution of EMP binary systems is biased toward short periods, unless the binary fraction of low-mass EMP stars is significantly higher than that of other nearby stars.

  2. High-resolution spectroscopy of extremely metal-poor stars from SDSS/Segue. II. Binary fraction

    SciTech Connect

    Aoki, Wako; Suda, Takuma; Beers, Timothy C.; Honda, Satoshi E-mail: takuma.suda@nao.ac.jp E-mail: honda@nhao.jp

    2015-02-01

    The fraction of binary systems in various stellar populations of the Galaxy and the distribution of their orbital parameters are important but not well-determined factors in studies of star formation, stellar evolution, and Galactic chemical evolution. While observational studies have been carried out for a large sample of nearby stars, including some metal-poor Population II stars, almost no constraints on the binary nature for extremely metal-poor (EMP; [Fe/H] <−3.0) stars have yet been obtained. Here we investigate the fraction of double-lined spectroscopic binaries and carbon-enhanced metal-poor (CEMP) stars, many of which could have formed as pairs of low-mass and intermediate-mass stars, to estimate the lower limit of the fraction of binary systems having short periods. The estimate is based on a sample of very metal-poor stars selected from the Sloan Digital Sky Survey and observed at high spectral resolution in a previous study by Aoki et al. That survey reported 3 double-lined spectroscopic binaries and 11 CEMP stars, which we consider along with a sample of EMP stars from the literature compiled in the SAGA database. We have conducted measurements of the velocity components for stacked absorption features of different spectral lines for each double-lined spectroscopic binary. Our estimate indicates that the fraction of binary stars having orbital periods shorter than 1000 days is at least 10%, and possibly as high as 20% if the majority of CEMP stars are formed in such short-period binaries. This result suggests that the period distribution of EMP binary systems is biased toward short periods, unless the binary fraction of low-mass EMP stars is significantly higher than that of other nearby stars.

  3. High sensitivity gas sensor based on high-Q suspended polymer photonic crystal nanocavity

    SciTech Connect

    Clevenson, Hannah Desjardins, Pierre; Gan, Xuetao; Englund, Dirk

    2014-06-16

    We present high-sensitivity, multi-use optical gas sensors based on a one-dimensional photonic crystal cavity. These devices are implemented in versatile, flexible polymer materials which swell when in contact with a target gas, causing a measurable cavity length change. This change causes a shift in the cavity resonance, allowing precision measurements of gas concentration. We demonstrate suspended polymer nanocavity sensors and the recovery of sensors after the removal of stimulant gas from the system. With a measured quality factor exceeding 10{sup 4}, we show measurements of gas concentration as low as 600 parts per million (ppm) and an experimental sensitivity of 10 ppm; furthermore, we predict detection levels in the parts-per-billion range for a variety of gases.

  4. Evaluation of the potential of different high calorific waste fractions for the preparation of solid recovered fuels.

    PubMed

    Garcés, Diego; Díaz, Eva; Sastre, Herminio; Ordóñez, Salvador; González-LaFuente, José Manuel

    2016-01-01

    Solid recovered fuels constitute a valuable alternative for the management of those non-hazardous waste fractions that cannot be recycled. The main purpose of this research is to assess the suitability of three different wastes from the landfill of the local waste management company (COGERSA), to be used as solid recovered fuels in a cement kiln near their facilities. The wastes analyzed were: End of life vehicles waste, packaging and bulky wastes. The study was carried out in two different periods of the year: November 2013 and April 2014. In order to characterize and classify these wastes as solid recovered fuels, they were separated into homogeneous fractions in order to determine different element components, such as plastics, cellulosic materials, packagings or textile compounds, and the elemental analysis (including chlorine content), heavy metal content and the heating value of each fraction were determined. The lower heating value of the waste fractions on wet basis varies between 10 MJ kg(-1) and 42 MJ kg(-1). One of the packaging wastes presents a very high chlorine content (6.3 wt.%) due to the presence of polyvinylchloride from pipe fragments, being the other wastes below the established limits. Most of the wastes analyzed meet the heavy metals restrictions, except the fine fraction of the end of life vehicles waste. In addition, none of the wastes exceed the mercury limit content, which is one of the parameters considered for the solid recovered fuels classification. A comparison among the experimental higher heating values and empirical models that predict the heating value from the elemental analysis data was carried out. Finally, from the three wastes measured, the fine fraction of the end of life vehicles waste was discarded for its use as solid recovered fuels due to the lower heating value and its high heavy metals content. From the point of view of the heating value, the end of life vehicles waste was the most suitable residue with a lower

  5. Evaluation of the potential of different high calorific waste fractions for the preparation of solid recovered fuels.

    PubMed

    Garcés, Diego; Díaz, Eva; Sastre, Herminio; Ordóñez, Salvador; González-LaFuente, José Manuel

    2016-01-01

    Solid recovered fuels constitute a valuable alternative for the management of those non-hazardous waste fractions that cannot be recycled. The main purpose of this research is to assess the suitability of three different wastes from the landfill of the local waste management company (COGERSA), to be used as solid recovered fuels in a cement kiln near their facilities. The wastes analyzed were: End of life vehicles waste, packaging and bulky wastes. The study was carried out in two different periods of the year: November 2013 and April 2014. In order to characterize and classify these wastes as solid recovered fuels, they were separated into homogeneous fractions in order to determine different element components, such as plastics, cellulosic materials, packagings or textile compounds, and the elemental analysis (including chlorine content), heavy metal content and the heating value of each fraction were determined. The lower heating value of the waste fractions on wet basis varies between 10 MJ kg(-1) and 42 MJ kg(-1). One of the packaging wastes presents a very high chlorine content (6.3 wt.%) due to the presence of polyvinylchloride from pipe fragments, being the other wastes below the established limits. Most of the wastes analyzed meet the heavy metals restrictions, except the fine fraction of the end of life vehicles waste. In addition, none of the wastes exceed the mercury limit content, which is one of the parameters considered for the solid recovered fuels classification. A comparison among the experimental higher heating values and empirical models that predict the heating value from the elemental analysis data was carried out. Finally, from the three wastes measured, the fine fraction of the end of life vehicles waste was discarded for its use as solid recovered fuels due to the lower heating value and its high heavy metals content. From the point of view of the heating value, the end of life vehicles waste was the most suitable residue with a lower

  6. Determination of fractional energy loss of waves in nearshore waters using an improved high-order Boussinesq-type model

    NASA Astrophysics Data System (ADS)

    He, Hailun; Song, Jinbao; Lynett, Patrick J.; Li, Shuang

    2009-09-01

    Fractional energy losses of waves due to wave breaking when passing over a submerged bar are studied systematically using a modified numerical code that is based on the high-order Boussinesq-type equations. The model is first tested by the additional experimental data, and the model’s capability of simulating the wave transformation over both gentle slope and steep slope is demonstrated. Then, the model’s breaking index is replaced and tested. The new breaking index, which is optimized from the several breaking indices, is not sensitive to the spatial grid length and includes the bottom slopes. Numerical tests show that the modified model with the new breaking index is more stable and efficient for the shallow-water wave breaking. Finally, the modified model is used to study the fractional energy losses for the regular waves propagating and breaking over a submerged bar. Our results have revealed that how the nonlinearity and the dispersion of the incident waves as well as the dimensionless bar height (normalized by water depth) dominate the fractional energy losses. It is also found that the bar slope (limited to gentle slopes that less than 1:10) and the dimensionless bar length (normalized by incident wave length) have negligible effects on the fractional energy losses.

  7. Manufacture and Testing of a High Field Gradient Magnetic Fractionation System for Quantitative Detection of Plasmodium falciparum Gametocytes

    NASA Astrophysics Data System (ADS)

    Karl, Stephan; Woodward, Robert C.; Davis, Timothy M. E.; St. Pierre, Tim G.

    2010-12-01

    Plasmodium falciparum is the most dangerous of the human malaria parasite species and accounts for millions of clinical episodes of malaria each year in tropical countries. The pathogenicity of Plasmodium falciparum is a result of its ability to infect erythrocytes where it multiplies asexually over 48 h or develops into sexual forms known as gametocytes. If sufficient male and female gametocytes are taken up by a mosquito vector, it becomes infectious. Therefore, the presence and density of gametocytes in human blood is an important indicator of human-to-mosquito transmission of malaria. Recently, we have shown that high field gradient magnetic fractionation improves gametocyte detection in human blood samples. Here we present two important new developments. Firstly we introduce a quantitative approach to replace the previous qualitative method and, secondly, we describe a novel method that enables cost-effective production of the magnetic fractionation equipment required to carry out gametocyte quantification. We show that our custom-made magnetic fractionation equipment can deliver results with similar sensitivity and convenience but for a small fraction of the cost.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. Enhanced resolution of Mentha piperita volatile fraction using a novel medium-polarity ionic liquid gas chromatography stationary phase.

    PubMed

    Ragonese, Carla; Sciarrone, Danilo; Grasso, Elisa; Dugo, Paola; Mondello, Luigi

    2016-02-01

    The evaluation of a novel medium-polarity ionic-liquid-based gas chromatography column, SLB-IL60, towards the analysis of a complex essential oil, namely, a peppermint essential oil sample, is reported. The SLB-IL60 30 m column was subjected to bleeding measurements, by means of conventional gas chromatography with mass spectrometry. The SLB-IL60 column was then evaluated in the analysis of pure standard compounds, chosen as typical constituents of peppermint essential oil. Resolution and peak symmetry (expressed as tailing factors at 10% of peak height) were measured and the results were compared to those obtained on the most widely used columns in such an application, namely a medium-polarity [100% poly(ethyleneglycol)] stationary phase, and an apolar 5% diphenyl/95% dimethyl siloxane. The final part of the evaluation was dedicated to the gas chromatography with mass spectrometry analysis of a peppermint essential oil sample and again the data were compared to those obtained on the 100% poly(ethyleneglycol) and the 5% diphenyl/95% dimethyl siloxane phase. Linear retention indices were determined for all the identified components on the ionic liquid capillary.

  13. Enhanced resolution of Mentha piperita volatile fraction using a novel medium-polarity ionic liquid gas chromatography stationary phase.

    PubMed

    Ragonese, Carla; Sciarrone, Danilo; Grasso, Elisa; Dugo, Paola; Mondello, Luigi

    2016-02-01

    The evaluation of a novel medium-polarity ionic-liquid-based gas chromatography column, SLB-IL60, towards the analysis of a complex essential oil, namely, a peppermint essential oil sample, is reported. The SLB-IL60 30 m column was subjected to bleeding measurements, by means of conventional gas chromatography with mass spectrometry. The SLB-IL60 column was then evaluated in the analysis of pure standard compounds, chosen as typical constituents of peppermint essential oil. Resolution and peak symmetry (expressed as tailing factors at 10% of peak height) were measured and the results were compared to those obtained on the most widely used columns in such an application, namely a medium-polarity [100% poly(ethyleneglycol)] stationary phase, and an apolar 5% diphenyl/95% dimethyl siloxane. The final part of the evaluation was dedicated to the gas chromatography with mass spectrometry analysis of a peppermint essential oil sample and again the data were compared to those obtained on the 100% poly(ethyleneglycol) and the 5% diphenyl/95% dimethyl siloxane phase. Linear retention indices were determined for all the identified components on the ionic liquid capillary. PMID:26613675

  14. 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.

  15. 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.

  16. A completion design for high-capacity offshore gas wells

    SciTech Connect

    Hartley, R.

    1983-04-01

    Sarawak Shell Bhd. (SSB) is currently developing two offshore gas fields to supply about 1,200 MMscf/D (34.3 x 10/sup 6/ std m/sup 3//d) to a liquid natural gas (LNG) plant being built at Bintulu, Sarawak. Both fields are carbonate buildups with very high productivities but, because of their relatively shallow depth, only moderate reservoir pressure. The produced gas is lean, with CO/sub 2/ content of up to 7.3% and H/sub 2/S content of about 8 ppm. Because the wells are offshore, there is increased risk caused by the proximity of other wells and the possibility of platform damage. Being offshore also means high costs for drilling, compression, and workover. This paper 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. (17.8-cm) tubulars, including 13% Cr steel at points where corrosion may be severe, and uses a fire-resistant Christmas tree and wellhead design.

  17. 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

    2006-11-01

    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. PMID:17073487

  18. GC/MS analysis of high-performance liquid chromatography fractions from Sophora flavescens and Torilis japonica extracts and their in vitro anti-neosporal effects on Neospora caninum.

    PubMed

    Seo, Hun-Su; Kim, Kyoung Hee; Kim, Dae-Yong; Park, Bong-Kyun; Shin, Nam-Shik; Kim, Jae-Hoon; Youn, Heejeong

    2013-01-01

    We analyzed alcoholic extracts of herbs possessing anti-neosporal activity against Neospora (N.) caninum. To identify the chemical components of Sophora (S.) flavescens and Torilis (T.) japonica associated with anti-neosporal activity, specific fractions were isolated by high-performance liquid chromatography (HPLC). In vitro activity of the fractions against N. caninum was then assessed. Gas chromatography/ mass spectrometry (GC/MS) was used to identify and quantify specific anti-neosporal molecules in the herbal extracts. Almost all HPLC fractions of S. flavescens and T. japonica had higher levels of anti-neosporal activity compared to the not treated control. Active constituents of the extracts were sophoridane, furosardonin A, and tetraisopropylidene-cyclobutane in S. flavescens; 5,17-β-dihydroxy-de-A-estra-5,7,9,14-tetraene, furanodiene, and 9,12-octadecadienoic acid (Z,Z)-(CAS,1) in T. japonica. PMID:23820198

  19. Multiple-injection high-throughput gas chromatography analysis.

    PubMed

    Schafer, Wes; Wang, Heather; Welch, Christopher J

    2016-08-01

    Multiple-injection techniques have been shown to be a simple way to perform high-throughput analysis where the entire experiment resides in a single chromatogram, simplifying the data analysis and interpretation. In this study, multiple-injection techniques are applied to gas chromatography with flame ionization detection and mass detection to significantly increase sample throughput. The unique issues of implementing a traditional "Fast" injection mode of multiple-injection techniques with gas chromatography and mass spectrometry are discussed. Stacked injections are also discussed as means to increase the throughput of longer methods where mass detection is unable to distinguish between analytes of the same mass and longer retentions are required to resolve components of interest. Multiple-injection techniques are shown to increase instrument throughput by up to 70% and to simplify data analysis, allowing hits in multiple parallel experiments to be identified easily. PMID:27292909

  20. 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.

  1. Startup analysis for a high temperature gas loaded heat pipe

    NASA Technical Reports Server (NTRS)

    Sockol, P. M.

    1973-01-01

    A model for the rapid startup of a high-temperature gas-loaded heat pipe is presented. A two-dimensional diffusion analysis is used to determine the rate of energy transport by the vapor between the hot and cold zones of the pipe. The vapor transport rate is then incorporated in a simple thermal model of the startup of a radiation-cooled heat pipe. Numerical results for an argon-lithium system show that radial diffusion to the cold wall can produce large vapor flow rates during a rapid startup. The results also show that startup is not initiated until the vapor pressure p sub v in the hot zone reaches a precise value proportional to the initial gas pressure p sub i. Through proper choice of p sub i, startup can be delayed until p sub v is large enough to support a heat-transfer rate sufficient to overcome a thermal load on the heat pipe.

  2. A novel technique for highly accurate gas exchange measurements

    NASA Astrophysics Data System (ADS)

    Kalkenings, R. K.; Jähne, B. J.

    2003-04-01

    The Heidelberg Aeolotron is a circular wind-wave facility for investigating air-sea gas exchange. In this contribution a novel technique for measuring highly accurate transfer velocities k of mass transfer will be presented. Traditionally, in mass balance techniques the constant of decay for gas concentrations over time is measured. The major drawback of this concept is the long time constant. At low wind speeds and a water height greater than 1 m the period of observation has to be several days. In a gas-tight facility such as the Aeolotron, the transfer velocity k can be computed from the concentration in the water body and the change of concentration in the gas space. Owing to this fact, transfer velocities are gained while greatly reducing the measuring times to less than one hour. The transfer velocity k of a tracer can be parameterized as k=1/β \\cdot u_* \\cdot Sc^n, with the Schmidt Number Sc, shear velocity u_* and the dimensionless transfer resistance β. The Schmidt Number exponent n can be derived from simultaneous measurements of different tracers. Since these tracers are of different Schmidt number, the shear velocity is not needed. To allow for Schmidt numbers spanning a hole decade, in our experiments He, H_2, N_2O and F12 are used. The relative accuracy of measuring the transfer velocity was improved to less than 2%. In 9 consecutive experiments conducted at a wind speed of 6.2 m/s, the deviation of the Schmidt number exponent was found to be just under 0.02. This high accuracy will allow precisely determining the transition of the Schmidt number exponent from n=2/3 to n=0.5 from a flat to wavy water surface. In order to quantify gas exchange not only the wind speed is important. Surfactants have a pronounced effect on the wave field and lead to a drastic reduction in the transfer velocity. In the Aeolotron measurements were conducted with a variety of measuring devices, ranging from an imaging slope gauge (ISG) to thermal techniques with IR

  3. Characterization of Mycolic Acids in Total Fatty Acid Methyl Ester Fractions from Mycobacterium Species by High Resolution MALDI-TOFMS.

    PubMed

    Teramoto, Kanae; Suga, Mitsuo; Sato, Takafumi; Wada, Takayuki; Yamamoto, Atsushi; Fujiwara, Nagatoshi

    2015-01-01

    Mycolic acids (MAs) are characteristic components of bacteria in the suborder Corynebacterineae, such as Mycobacterium. MAs are categorized into subclasses based on their functional bases (cyclopropane ring, methoxy, keto, and epoxy group). Since MAs have heterogeneity among bacterial species, analyzing of MAs are required in the chemotaxonomic field. However, their structural analysis is not easy because of their long carbon-chain lengths and several functional groups. In this study, total fatty acid (FA) methyl ester (ME) fraction of M. tuberculosis H37Rv was analyzed by matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometry (TOFMS) with a spiral ion trajectory (MALDI spiral-TOFMS). The distributions of carbon-chain length and their relative peak intensities were confirmed with those obtained by analysis of each subclass fraction which was separated from total FA ME fraction using thin-layer chromatography (TLC). The observed major peaks were reliably assigned as MAs owing to the high mass accuracy (error<3 ppm). The types of MA subclasses, their distributions of carbon-chain lengths, their relative peak intensities, and the ratio of even- and odd-numbered carbon-chain MAs for the total FA ME fraction were consistent with those of MA subclass fractions. To visualize whole MAs, contour maps of relative peak intensities for whole MAs were created. The contour maps indicated the MA subclasses and their distributions of carbon-chains with relative peak intensities at a glance. Our proposed method allows simple characterization in a short time and thus enables the analysis of large numbers of samples, and it would contribute to the chemotaxonomy. PMID:26819906

  4. 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.

  5. 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.

  6. 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

  7. 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

  8. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of semivolatile organic compounds in bottom sediment by solvent extraction, gel permeation chromatographic fractionation, and capillary-column gas chromatography/mass spectrometry

    USGS Publications Warehouse

    Furlong, E.T.; Vaught, D.G.; Merten, L.M.; Foreman, W.T.; Gates, Paul M.

    1996-01-01

    A method for the determination of 79 semivolatile organic compounds (SOCs) and 4 surrogate compounds in soils and bottom sediment is described. The SOCs are extracted from bottom sediment by solvent extraction, followed by partial isolation using high-performance gel permeation chromatography (GPC). The SOCs then are qualitatively identified and quantitative concentrations determined by capillary-column gas chromatography/mass spectrometry (GC/MS). This method also is designed for an optional simultaneous isolation of polychlorinated biphenyls (PCBs) and organochlorine (OC) insecticides, including toxaphene. When OCs and PCBs are determined, an additional alumina- over-silica column chromatography step follows GPC cleanup, and quantitation is by dual capillary- column gas chromatography with electron-capture detection (GC/ECD). Bottom-sediment samples are centrifuged to remove excess water and extracted overnight with dichloromethane. The extract is concentrated, centrifuged, and then filtered through a 0.2-micrometer polytetrafluoro-ethylene syringe filter. Two aliquots of the sample extract then are quantitatively injected onto two polystyrene- divinylbenzene GPC columns connected in series. The SOCs are eluted with dichloromethane, a fraction containing the SOCs is collected, and some coextracted interferences, including elemental sulfur, are separated and discarded. The SOC-containing GPC fraction then is analyzed by GC/MS. When desired, a second aliquot from GPC is further processed for OCs and PCBs by combined alumina-over-silica column chromatography. The two fractions produced in this cleanup then are analyzed by GC/ECD. This report fully describes and is limited to the determination of SOCs by GC/MS.

  9. Identification of metabolites from an active fraction of Cajanus cajan seeds by high resolution mass spectrometry.

    PubMed

    Tekale, Satishkumar S; Jaiwal, Bhimrao V; Padul, Manohar V

    2016-11-15

    Antioxidants are important food additives which prolong food storage due to their protective effects against oxidative degradation of foods by free radicals. However, the synthetic antioxidants show toxic properties. Alternative economical and eco-friendly approach is screening of plant extract for natural antioxidants. Plant phenolics are potent antioxidants. Hence, in present study Cajanus cajan seeds were analyzed for antioxidant activity, Iron chelating activity and total phenolic content. The antioxidant activity using DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay showed 71.3% inhibition and 65.8% Iron chelating activity. Total 37 compounds including some short peptides and five major abundant compounds were identified in active fraction of C. cajan seeds. This study concludes that C. cajan seeds are good source of antioxidants and Iron chelating activity. Metabolites found in C. cajan seeds which remove reactive oxygen species (ROS), may help to alleviate oxidative stress associated dreaded health problem like cancer and cardiovascular diseases. PMID:27283694

  10. High-speed mixture fraction and temperature imaging of pulsed, turbulent fuel jets auto-igniting in high-temperature, vitiated co-flows

    NASA Astrophysics Data System (ADS)

    Papageorge, Michael J.; Arndt, Christoph; Fuest, Frederik; Meier, Wolfgang; Sutton, Jeffrey A.

    2014-07-01

    In this manuscript, we describe an experimental approach to simultaneously measure high-speed image sequences of the mixture fraction and temperature fields during pulsed, turbulent fuel injection into a high-temperature, co-flowing, and vitiated oxidizer stream. The quantitative mixture fraction and temperature measurements are determined from 10-kHz-rate planar Rayleigh scattering and a robust data processing methodology which is accurate from fuel injection to the onset of auto-ignition. In addition, the data processing is shown to yield accurate temperature measurements following ignition to observe the initial evolution of the "burning" temperature field. High-speed OH* chemiluminescence (CL) was used to determine the spatial location of the initial auto-ignition kernel. In order to ensure that the ignition kernel formed inside of the Rayleigh scattering laser light sheet, OH* CL was observed in two viewing planes, one near-parallel to the laser sheet and one perpendicular to the laser sheet. The high-speed laser measurements are enabled through the use of the unique high-energy pulse burst laser system which generates long-duration bursts of ultra-high pulse energies at 532 nm (>1 J) suitable for planar Rayleigh scattering imaging. A particular focus of this study was to characterize the fidelity of the measurements both in the context of the precision and accuracy, which includes facility operating and boundary conditions and measurement of signal-to-noise ratio (SNR). The mixture fraction and temperature fields deduced from the high-speed planar Rayleigh scattering measurements exhibited SNR values greater than 100 at temperatures exceeding 1,300 K. The accuracy of the measurements was determined by comparing the current mixture fraction results to that of "cold", isothermal, non-reacting jets. All profiles, when properly normalized, exhibited self-similarity and collapsed upon one another. Finally, example mixture fraction, temperature, and OH* emission

  11. Particle size fractionation of high-amylose rice (Goami 2) flour as an oil barrier in a batter-coated fried system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The particle size effects of high-amylose rice (Goami 2) flour on quality attributes of frying batters were characterized in terms of physicochemical, rheological, and oil-resisting properties. High-amylose rice flours were fractionated into four fractions (70, 198, 256, and 415 µm) of which morpho...

  12. Specimen Preparation for Metal Matrix Composites with a High Volume Fraction of Reinforcing Particles for EBSD Analysis

    NASA Astrophysics Data System (ADS)

    Smirnov, A. S.; Belozerov, G. A.; Smirnova, E. O.; Konovalov, A. V.; Shveikin, V. P.; Muizemnek, O. Yu.

    2016-07-01

    The paper deals with a procedure of preparing a specimen surface for the EBSD analysis of a metal matrix composite (MMC) with a high volume fraction of reinforcing particles. Unlike standard procedures of preparing a specimen surface for the EBSD analysis, the proposed procedure is iterative with consecutive application of mechanical and electrochemical polishing. This procedure significantly improves the results of an indexed MMC matrix in comparison with the standard procedure of specimen preparation. The procedure was verified on a MMC with pure aluminum (99.8% Al) as the matrix, SiC particles being used as reinforcing elements. The average size of the SiC particles is 14 μm, and their volume fraction amounts to 50% of the total volume of the composite. It has been experimentally found that, for making the EBSD analysis of a material matrix near reinforcing particles, the difference in height between the particles and the matrix should not exceed 2 µm.

  13. Fractionation of polyphenols in hawthorn into polymeric procyanidins, phenolic acids and flavonoids prior to high-performance liquid chromatographic analysis.

    PubMed

    Svedström, Ulla; Vuorela, Heikki; Kostiainen, Risto; Laakso, Into; Hiltunen, Raimo

    2006-04-21

    Polymeric procyanidins, phenolic carboxylic acids and flavonoids of hawthorn (Crataegus laevigata) were fractionated prior to HPLC analysis using column chromatography and solid-phase extraction (SPE). The flavonoid fraction also contained (-)-epicatechin. The three groups of phenolics, each with clearly different UV spectra, were examined by means of high-performance liquid chromatography-diode array detection (HPLC-DAD) analysis. The average repeatability of the method (RSD) was in the range of 8-13% for chlorogenic acid, (-)-epicatechin and hyperoside. The polymeric procyanidins of hawthorn flowers consisted mainly of (-)-epicatechin subunits, and their mean degree of polymerization (DP) was 22.2. The HPLC methods developed can be used for the qualitative and quantitative analysis of different phenolic compounds in hawthorn plant material and their extracts.

  14. Expanded Lever Rule for Phase Volume Fraction Calculation of High-Strength Low-Alloy Steel in Thermal Simulation

    NASA Astrophysics Data System (ADS)

    Lei, Xuanwei; Huang, Jihua; Chen, Shuhai; Zhao, Xingke

    2016-06-01

    The principle of the lever rule on the dilatation curve and its application to the corresponding differential dilatation curve were introduced in a nonoverlapped two-phase continuous cooling process. The lever rule was further expanded in the case of an overlapped two-phase process. The application of the expanded lever rule was based on the approximate symmetry treatment on the differential dilatation curve, which shows reasonably both on the theoretical calculation and in the experimental results. High-strength low-alloy steels were thermal simulated with Gleeble 3500. The transformed phase volume fractions in different cooling processes were calculated by the expanded lever rule and metallography analysis. The results showed the expanded lever rule could calculate reliable phase volume fractions as metallography analysis.

  15. Manifestation of anomalous Floquet states with longevity in dynamic fractional Stark ladder with high AC electric fields

    NASA Astrophysics Data System (ADS)

    Nemoto, Yuya; Ohno, Fumitaka; Maeshima, Nobuya; Hino, Ken-ichi

    2016-09-01

    We examine a resonance structure of Floquet state in dynamic fractional Stark ladder (DFSL) realized in biased semiconductor superlattices driven by a terahertz cw laser on the basis of the R-matrix Floquet theory. To do this, we calculate an excess density of state ρ (ex)(E) corresponding to lifetime of the Floquet state with a fractional matching ratio η, where η is the ratio of a Bloch frequency ΩB to a laser frequency ω, namely, η =ΩB / ω. The results for η = 3 / 2 demonstrate the appearance of discernibly large peaks associated with Floquet states with longevity in a region of relatively high laser-intensity. The underlying physics is discussed in terms of an analytical expression of ρ (ex)(E) and the associated Green function in which ponderomotive couplings are included in a non-perturbative way.

  16. High performance liquid chromatographic hydrocarbon group-type analyses of mid-distillates employing fuel-derived fractions as standards

    NASA Technical Reports Server (NTRS)

    Seng, G. T.; Otterson, D. A.

    1983-01-01

    Two high performance liquid chromatographic (HPLC) methods have been developed for the determination of saturates, olefins and aromatics in petroleum and shale derived mid-distillate fuels. In one method the fuel to be analyzed is reacted with sulfuric acid, to remove a substantial portion of the aromatics, which provides a reacted fuel fraction for use in group type quantitation. The second involves the removal of a substantial portion of the saturates fraction from the HPLC system to permit the determination of olefin concentrations as low as 0.3 volume percent, and to improve the accuracy and precision of olefins determinations. Each method was evaluated using model compound mixtures and real fuel samples.

  17. 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).

  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. 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.

  2. 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.

  3. Enhanced characterization of oil sands acid-extractable organics fractions using electrospray ionization-high-resolution mass spectrometry and synchronous fluorescence spectroscopy.

    PubMed

    Bauer, Anthony E; Frank, Richard A; Headley, John V; Peru, Kerry M; Hewitt, L Mark; Dixon, D George

    2015-05-01

    The open pit oil sands mining operations north of Fort McMurray, Alberta, Canada, are accumulating tailings waste at a rate approximately equal to 4.9 million m(3) /d. Naphthenic acids are among the most toxic components within tailings to aquatic life, but structural components have largely remained unidentified. In the present study, electrospray ionization high-resolution mass spectrometry (ESI-HRMS) and synchronous fluorescence spectroscopy (SFS) were used to characterize fractions derived from the distillation of an acid-extractable organics (AEO) mixture isolated from oil sands process-affected water (OSPW). Mean molecular weights of each fraction, and their relative proportions to the whole AEO extract, were as follows: fraction 1: 237 Da, 8.3%; fraction 2: 240 Da, 23.8%; fraction 3: 257 Da, 26.7%; fraction 4: 308 Da, 18.9%; fraction 5: 355 Da, 10.0%. With increasing mean molecular weight of the AEO fractions, a concurrent increase occurred in the relative abundance of nitrogen-, sulfur-, and oxygen-containing ions, double-bond equivalents, and degree of aromaticity. Structures present in the higher-molecular-weight fractions (fraction 4 and fraction 5) suggested the presence of heteroatoms, dicarboxyl and dihydroxy groups, and organic acid compounds with the potential to function as estrogens. Because organic acid compositions become dominated by more recalcitrant, higher-molecular-weight acids during natural degradation, these findings are important in the context of oil sands tailings pond water remediation.

  4. Enhanced characterization of oil sands acid-extractable organics fractions using electrospray ionization-high-resolution mass spectrometry and synchronous fluorescence spectroscopy.

    PubMed

    Bauer, Anthony E; Frank, Richard A; Headley, John V; Peru, Kerry M; Hewitt, L Mark; Dixon, D George

    2015-05-01

    The open pit oil sands mining operations north of Fort McMurray, Alberta, Canada, are accumulating tailings waste at a rate approximately equal to 4.9 million m(3) /d. Naphthenic acids are among the most toxic components within tailings to aquatic life, but structural components have largely remained unidentified. In the present study, electrospray ionization high-resolution mass spectrometry (ESI-HRMS) and synchronous fluorescence spectroscopy (SFS) were used to characterize fractions derived from the distillation of an acid-extractable organics (AEO) mixture isolated from oil sands process-affected water (OSPW). Mean molecular weights of each fraction, and their relative proportions to the whole AEO extract, were as follows: fraction 1: 237 Da, 8.3%; fraction 2: 240 Da, 23.8%; fraction 3: 257 Da, 26.7%; fraction 4: 308 Da, 18.9%; fraction 5: 355 Da, 10.0%. With increasing mean molecular weight of the AEO fractions, a concurrent increase occurred in the relative abundance of nitrogen-, sulfur-, and oxygen-containing ions, double-bond equivalents, and degree of aromaticity. Structures present in the higher-molecular-weight fractions (fraction 4 and fraction 5) suggested the presence of heteroatoms, dicarboxyl and dihydroxy groups, and organic acid compounds with the potential to function as estrogens. Because organic acid compositions become dominated by more recalcitrant, higher-molecular-weight acids during natural degradation, these findings are important in the context of oil sands tailings pond water remediation. PMID:25615406

  5. Efficacy of Oral Curcuminoid Fraction from Curcuma xanthorrhiza and Curcuminoid Cider in High-cholesterol Fed Rats

    PubMed Central

    Mauren, Flavia Maria; Yanti; Lay, Bibiana Widiati

    2016-01-01

    Background: Hypercholesterolemia is one of the most important risk factors for atherosclerosis and subsequent cardiovascular diseases. Objective: The present work was aimed to study the efficacy of curcuminoid fraction from Curcuma xanthorrhiza and its curcuminoid cider in reducing blood cholesterol level and four genes related to oxidative stress, including cluster of differentiation 44 (CD44), intercellular adhesion molecule 1 (ICAM-1), inducible nitric oxide synthase (iNOS), and lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) in high-cholesterol fed rats in vivo. Materials and Methods: Twenty-four male Sprague-Dawley rats were divided into six groups, namely normal group diet, high-cholesterol diet (HCD) 2%, HCD + 100 mg/kg b.w. curcuminoid fraction, HCD + 300 mg/kg b.w. curcuminoid fraction, HCD + cider 1% v/v, and HCD + curcuminoid cider 2% v/v for 4 weeks. Total cholesterol levels were measured at day 1, 14, and 28. Vascular tissues and organs from lung and liver were collected for RNA extraction, followed by quantitative analysis using real-time polymerase chain reaction (PCR). Results: Our results demonstrated that among all the treatment groups, curcuminoid cider at 2% v/v significantly lowered total cholesterol level compared to those of positive control. Real-time PCR data showed both curcuminoid fractions (100 and 300 mg/kg) and curcuminoid cider (1 and 2% v/v) inhibited the gene expression of CD44, ICAM-1, iNOS, and LOX-1, indicating their hypocholesterolemic effects via attenuating genes related to oxidative stress in rats in vivo. Conclusion: Oral administration of curcuminoid fraction and its cider product may exert potential inhibitory effects on oxidative stress related-genes for preventing hypercholesterolemia-induced atherosclerosis in vivo. SUMMARY Curcuminoid and its cider significantly inhibited the gene expression of CD44, ICAM-1, iNOS, and LOX-1 in rats in vivoCurcuminoid and its cider suppressed oxidative stress

  6. Evaluation of MODIS-Derived Cloud Fraction Using Surface Observations at Low-, Mid- and High Latitude DOE ARM sites

    NASA Astrophysics Data System (ADS)

    Wang, Yang; Zhao, Chuanfeng

    2016-04-01

    using the 1-hour averaged observations at both 10:30 AM and 1:30 PM. Comparison results will be shown in our paper. It shows a high correlation coefficient of 0.95 (0.93) for observations from TSC (ARSCL). The ratios of daily (monthly) averaged cloud fraction between using all time and using the time satellite passes are 0.87(0.92) and 0.86(0.97) for TSC and ARSCL, respectively. This suggests that considerable errors could be introduced while using the cloud fraction at two fixed time points (10:30 AM and 1:30 PM) to represent the daily cloud fraction.

  7. The binary fraction of planetary nebula central stars - I. A high-precision, I-band excess search

    NASA Astrophysics Data System (ADS)

    De Marco, Orsola; Passy, Jean-Claude; Frew, D. J.; Moe, Maxwell; Jacoby, G. H.

    2013-01-01

    We still do not know what causes aspherical planetary nebula (PN) morphologies. A plausible hypothesis is that they are due to the presence of a close stellar or substellar companion. So far, only ˜40 binary central stars of PN have been detected, almost all of them with such short periods that their binarity is revealed by photometric variability. Here we have endeavoured to discover binary central stars at any separation, thus determining the unbiased binary fraction of central stars of PN. This number, when compared to the binary fraction of the presumed parent population, can give a first handle on the origin of PN. By detecting the central stars in the I band we have searched for cool companions. We have found that 30 per cent of our sample have an I-band excess detected between 1 and a few σ, possibly denoting companions brighter than M3-4V and with separations smaller than ˜1000 au. By accounting for the undetectable companions, we determine a debiased binary fraction of 67-78 per cent for all companions at all separations. We compare this number to a main-sequence binary fraction of (50 ± 4) per cent determined for spectral types F6V-G2V, appropriate if the progenitors of today's PN central star population are indeed the F6V-G2V stars. The error on our estimate cannot be constrained tightly, but we determine it to be between 10 and 30 per cent. We conclude that the central star binary fraction may be larger than expected from the putative parent population. However, this result is based on a sample of 27 bona fide central stars and should be considered preliminary. The success of the I-band method rests critically on high-precision photometry and a reasonably large sample. From a similar analysis, using the more sensitive J band of a subset of 11 central stars, the binary fraction is 54 per cent for companions brighter than ˜M5-6V and with separations smaller than about 900 au. Debiasing this number in the same way as was done for the I band we obtain

  8. Behaviour and stability of Trivelpiece-Gould modes in non-neutral plasma containing small density fraction of background gas ions

    NASA Astrophysics Data System (ADS)

    Yeliseyev, Y. N.

    2013-03-01

    It is shown that the frequencies of Trivelpiece-Gould (TG) modes in non-neutral plasma can get into the low-frequency range due to the Doppler shift caused by plasma rotation in crossed fields. TG modes interact with the ion modes that leads to plasma instability. In paper the frequency spectrum of "cold" electron plasma completely filling a waveguide and containing small density fraction of ions of background gas is determined numerically. For ions the kinetic description is used. Oscillations having azimuthal number m = 2 are considered. In this case both low- and upper-hybrid TG modes get into the low-frequency range. The spectrum consists of families of "modified" ion cyclotron (MIC) modes and electron TG modes with the frequencies equal to hybrid frequencies with the Doppler shift. The growth rates of upper-hybrid modes are much faster than the growth rates of low-hybrid and MIC modes.

  9. Behaviour and stability of Trivelpiece-Gould modes in non-neutral plasma containing small density fraction of background gas ions

    SciTech Connect

    Yeliseyev, Y. N.

    2013-03-19

    It is shown that the frequencies of Trivelpiece-Gould (TG) modes in non-neutral plasma can get into the low-frequency range due to the Doppler shift caused by plasma rotation in crossed fields. TG modes interact with the ion modes that leads to plasma instability. In paper the frequency spectrum of 'cold' electron plasma completely filling a waveguide and containing small density fraction of ions of background gas is determined numerically. For ions the kinetic description is used. Oscillations having azimuthal number m= 2 are considered. In this case both low- and upper-hybrid TG modes get into the low-frequency range. The spectrum consists of families of 'modified' ion cyclotron (MIC) modes and electron TG modes with the frequencies equal to hybrid frequencies with the Doppler shift. The growth rates of upper-hybrid modes are much faster than the growth rates of low-hybrid and MIC modes.

  10. 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.

  11. High population attributable fractions of myocardial infarction associated with waist–hip ratio

    PubMed Central

    Igland, Jannicke; Vollset, Stein Emil; Sulo, Gerhard; Eide, Geir Egil; Tell, Grethe S.

    2016-01-01

    Objective To estimate population attributable fractions (PAF) of acute myocardial infarction (AMI) associated with anthropometric measures by sex and age. Methods The Cohort of Norway study identified 140,790 participants free of cardiovascular disease, 1994‐2003. Participants were followed for AMI through 2009 by record linkages through the Cardiovascular Disease in Norway Project. PAFs were adjusted for age, smoking, systolic blood pressure, diabetes, and the ratio of total cholesterol to high‐density lipoprotein cholesterol. Results The PAFs associated with a waist–hip ratio (WHR) in the top two quintiles were 26.1% (95% confidence interval, CI 14.6–36.1) for middle‐aged women (<60 years, mean of 41 years) and 9.3% (95% CI 3.0–15.1) for similarly aged men after adjustment for body mass index (BMI) and conventional risk factors. However, PAFs associated with anthropometric measures in elderly participants (≥ 60 years, mean of 70 years) were non‐significant in multivariable analyses. Also, WHR was a significant predictor of AMI among men and women without an enlarged waist circumference (<102 cm for men and < 88 cm for women) in adjusted analyses. Conclusions WHR measurements could improve identification of at‐risk individuals above and beyond that of conventional risk factors, BMI, or an enlarged waist circumference. PMID:27030172

  12. High-speed gas chromatography: an overview of various concepts.

    PubMed

    Cramers, C A; Janssen, H G; van Deursen, M M; Leclercq, P A

    1999-09-24

    An overview is given of existing methods to minimise the analysis time in gas chromatography (GC) being the subject of many publications in the scientific literature. Packed and (multi-) capillary columns are compared with respect to their deployment in fast GC. It is assumed that the contribution of the stationary phase to peak broadening can be neglected (low liquid phase loading and thin film columns, respectively). The treatment is based on the minimisation of the analysis time required on both column types for the resolution of a critical pair of solutes (resolution normalised conditions). Theoretical relationships are given, describing analysis time and the related pressure drop. The equations are expressed in reduced parameters, making a comparison of column types considerably simpler than with the conventional equations. Reduction of the characteristic diameter, being the inside column diameter for open tubular columns and the particle size for packed columns, is the best approach to increase the separation speed in gas chromatography. Extremely fast analysis is only possible when the required number of plates to separate a critical pair of solutes is relatively low. Reducing the analysis time by reduction of the characteristic diameter is accompanied by a proportionally higher required inlet pressure. Due to the high resistance of flow of packed columns this seriously limits the use of packed columns for fast GC. For fast GC hydrogen has to be used as carrier gas and in some situations vacuum-outlet operation of capillary columns allows a further minimisation of the analysis time. For fast GC the columns should be operated near the conditions for minimum plate height. Linear temperature programmed fast GC requires high column temperature programming rates. Reduction of the characteristic diameter affects the sample capacity of the "fast columns". This effect is very pronounced for narrow-bore columns and in principle non-existing in packed columns. Multi

  13. High-energy gas fracturing in cased and perforated wellbores

    SciTech Connect

    Cuderman, J.F.

    1986-06-01

    A propellant-based technology, High-Energy Gas Fracturing (HEGF), has been applied to fracturing through perforations in cased boreholes. HEGF is a tailored-pulse fracturing technique originally developed by Sandia National Laboratories for application in uncased, liquid-free gas wells in Appalachian Devonian shales. Because most oil and gas wells are liquid filled as well as cased and perforated, the potential impact of present research is significantly broader. A number of commercial tailored-pulse fracturing services, using a variety of explosives or propellants, are currently available. Present research provides valuable insight into phenomena that occur in those stimulations. The use of propellants that deflagrate or burn rather than detonate, as do high-order explosives, permits controlled buildup of pressure in the wellbore. The key to successful stimulation in cased and perforated wellbores is to control the pressure buildup of the combustion gases to maximize fracturing without destroying the casing. Eight experiments using cased and perforated wellbore were conducted in a tunnel complex at the Department of Energy's Nevada Test Site, which provides a realistic in situ stress environment (4 to 10 MPa (600 to 1500 psi)) and provides access for mineback to directly observe fracturing obtained. Primary variables in the experiments include propellant burn rate and amount of propellant used, presence or absence of liquid in the wellbore, in situ stress orientation, and perforation diameter, density, and phasing. In general, the presence of liquid in the borehole results in a much faster pressure risetime and a lower peak pressure for the same propellant charge. Fracture surfaces proceed outward along lines of perforations as determined by phasing, then gradually turn toward the hydraulic fracture direction. 8 refs., 23 figs., 3 tabs.

  14. Experimental detection of high-order or fractional orbital angular momentum of light based on a robust mode converter

    NASA Astrophysics Data System (ADS)

    Zhou, Jie; Zhang, Wuhong; Chen, Lixiang

    2016-03-01

    Based on our constructed robust π/2 mode converter, we report a concise yet high-efficient experiment to realize the detection of both high-order and fractional orbital angular momentum (OAM). The π/2 mode converter that consists of a pair of cylindrical lens is actually not new. However, our experiment shows clearly its excellent robustness, as we have detected the high-order OAM numbers up to ℓ = 100 carried by standard Laguerre-Gaussian (LG) modes. The observed patterns of two-dimensional optical lattices indicate that the radial index p of LG beams can be straightforwardly inferred as well. The versatility of the converter is also manifested by input modified LG beams carrying tunable fractional OAM, where we observe the output lattices exhibiting an interesting evolvement from Hermite-Gaussian mode HG m , 0 to its adjacent HG m + 1 , 0 . Numeric simulations based on OAM eigen-mode decomposition support the experimental results. Our demonstration has potential in both classical and quantum information applications where high OAM modes are needed.

  15. Leaf area index retrieval using gap fractions obtained from high resolution satellite data: Comparisons of approaches, scales and atmospheric effects

    NASA Astrophysics Data System (ADS)

    Gonsamo, Alemu

    2010-08-01

    This study is aimed at demonstrating the feasibility of the large scale LAI inversion algorithms using red and near infrared reflectance obtained from high resolution satellite imagery. Radiances in digital counts were obtained in 10 m resolution acquired on cloud free day of August 23, 2007, by the SPOT 5 high resolution geometric (HRG) instrument on mostly temperate hardwood forest located in the Great Lakes - St. Lawrence forest in Southern Quebec. Normalized difference vegetation index (NDVI), scaled difference vegetation index (SDVI) and modified soil-adjusted vegetation index (MSAVI) were applied to calculate gap fractions. LAI was inverted from the gap fraction using the common Beer-Lambert's law of light extinction under forest canopy. The robustness of the algorithm was evaluated using the ground-based LAI measurements and by applying the methods for the independently simulated reflectance data using PROSPECT + SAIL coupled radiative transfer models. Furthermore, the high resolution LAI was compared with MODIS LAI product. The effects of atmospheric corrections and scales were investigated for all of the LAI retrieval methods. NDVI was found to be not suitable index for large scale LAI inversion due to the sensitivity to scale and atmospheric effects. SDVI was virtually scale and atmospheric correction invariant. MSAVI was also scale invariant. Considering all sensitivity analysis, MSAVI performed best followed by SDVI for robust LAI inversion from high resolution imagery.

  16. 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.

  17. 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.

  18. Conventional and enantioselective gas chromatography with microfabricated planar columns for analysis of real-world samples of plant volatile fraction.

    PubMed

    Cagliero, C; Galli, S; Galli, M; Elmi, I; Belluce, M; Zampolli, S; Sgorbini, B; Rubiolo, P; Bicchi, C

    2016-01-15

    Within a project exploring the application of lab-on-chip GC to in-field analysis of the plant volatile fraction, this study evaluated the performance of a set of planar columns (also known as microchannels, MEMS columns, or microfabricated columns) of different dimensions installed in a conventional GC unit. Circular double-spiral-shaped-channel planar columns with different square/rectangular sections up to 2m long were applied to the analysis of both essential oils and headspace samples of a group of medicinal and aromatic plants (chamomile, peppermint, sage, rosemary, lavender and bergamot) and of standard mixtures of related compounds; the results were compared to those obtained with reference narrow-bore columns (l:5m, dc:0.1mm, df:0.1 μm). The above essential oils and headspaces were first analyzed quali-and quantitatively with planar columns statically coated with conventional stationary phases (5%-phenyl-polymethylsiloxane and auto-bondable nitroterephthalic-acid-modified polyethylene glycol), and then submitted to chiral recognition of their diagnostic markers, by enantioselective GC with a planar columns coated with a cyclodextrin derivative (30% 6(I-VII)-O-TBDMS-3(I-VII)-O-ethyl-2(I-VII)-O-ethyl-β-cyclodextrin in PS-086). Column characteristics and analysis conditions were first optimized to obtain suitable retention and efficiency for the samples investigated. The planar columns tested showed performances close to the reference conventional narrow-bore columns, with theoretical plate numbers per meter (N/m) ranging from 6100 to 7200 for those coated with the conventional stationary phases, and above 5600 for those with the chiral selector. PMID:26733393

  19. Low-profile high-voltage compact gas switch

    SciTech Connect

    Goerz, D.A.; Wilson, M.J.; Speer, R.D.

    1997-06-30

    This paper discusses the development and testing of a low-profile, high-voltage, spark-gap switch designed to be closely coupled with other components into an integrated high-energy pulsed-power source. The switch is designed to operate at 100 kV using SF6 gas pressurized to less than 0.7 MPa. The volume of the switch cavity region is less than 1.5 cm3, and the field stress along the gas-dielectric interface is as high as 130 kV/cm. The dielectric switch body has a low profile that is only I -cm tall at its greatest extent and nominally 2-mm thick over most of its area. This design achieves a very low inductance of less than 5 nH, but results in field stresses exceeding 500 kV/cm in the dielectric material. Field modeling was done to determine the appropriate shape for the highly stressed insulator and electrodes, and special manufacturing techniques were employed to mitigate the usual mechanisms that induce breakdown and failure in solid dielectrics. Static breakdown tests verified that the switch operates satisfactorily at 100 kV levels. The unit has been characterized with different shaped electrodes having nominal gap spacings of 2.0, 2.5, and 3.0 mm. The relationship between self-break voltage and operating pressure agrees well with published data on gas properties, accounting for the field enhancements of the electrode shapes being used. Capacitor discharge tests in a low inductance test fixture exhibited peak currents up to 25 kA with characteristic frequencies of the ringdown circuit ranging from 10 to 20 MHz. The ringdown waveforms and scaling of measured parameters agree well with circuit modeling of the switch and test fixture. Repetitive operation has been demonstrated at moderate rep-rates up to 15 Hz, limited by the power supply being used. Preliminary tests to evaluate lifetime of the compact switch assembly have been encouraging. In one case, after more than 7,000 high-current ringdown tests with approximately 30 C of total charge transferred, the

  20. High-Octane Fuel from Refinery Exhaust Gas: Upgrading Refinery Off-Gas to High-Octane Alkylate

    SciTech Connect

    2009-12-01

    Broad Funding Opportunity Announcement Project: Exelus is developing a method to convert olefins from oil refinery exhaust gas into alkylate, a clean-burning, high-octane component of gasoline. Traditionally, olefins must be separated from exhaust before they can be converted into another source of useful fuel. Exelus’ process uses catalysts that convert the olefin to alkylate without first separating it from the exhaust. The ability to turn up to 50% of exhaust directly into gasoline blends could result in an additional 46 million gallons of gasoline in the U.S. each year.

  1. Nanomechanical Behavior of High Gas Barrier Multilayer Thin Films.

    PubMed

    Humood, Mohammad; Chowdhury, Shahla; Song, Yixuan; Tzeng, Ping; Grunlan, Jaime C; Polycarpou, Andreas A

    2016-05-01

    Nanoindentation and nanoscratch experiments were performed on thin multilayer films manufactured using the layer-by-layer (LbL) assembly technique. These films are known to exhibit high gas barrier, but little is known about their durability, which is an important feature for various packaging applications (e.g., food and electronics). Films were prepared from bilayer and quadlayer sequences, with varying thickness and composition. In an effort to evaluate multilayer thin film surface and mechanical properties, and their resistance to failure and wear, a comprehensive range of experiments were conducted: low and high load indentation, low and high load scratch. Some of the thin films were found to have exceptional mechanical behavior and exhibit excellent scratch resistance. Specifically, nanobrick wall structures, comprising montmorillonite (MMT) clay and polyethylenimine (PEI) bilayers, are the most durable coatings. PEI/MMT films exhibit high hardness, large elastic modulus, high elastic recovery, low friction, low scratch depth, and a smooth surface. When combined with the low oxygen permeability and high optical transmission of these thin films, these excellent mechanical properties make them good candidates for hard coating surface-sensitive substrates, where polymers are required to sustain long-term surface aesthetics and quality.

  2. Nanomechanical Behavior of High Gas Barrier Multilayer Thin Films.

    PubMed

    Humood, Mohammad; Chowdhury, Shahla; Song, Yixuan; Tzeng, Ping; Grunlan, Jaime C; Polycarpou, Andreas A

    2016-05-01

    Nanoindentation and nanoscratch experiments were performed on thin multilayer films manufactured using the layer-by-layer (LbL) assembly technique. These films are known to exhibit high gas barrier, but little is known about their durability, which is an important feature for various packaging applications (e.g., food and electronics). Films were prepared from bilayer and quadlayer sequences, with varying thickness and composition. In an effort to evaluate multilayer thin film surface and mechanical properties, and their resistance to failure and wear, a comprehensive range of experiments were conducted: low and high load indentation, low and high load scratch. Some of the thin films were found to have exceptional mechanical behavior and exhibit excellent scratch resistance. Specifically, nanobrick wall structures, comprising montmorillonite (MMT) clay and polyethylenimine (PEI) bilayers, are the most durable coatings. PEI/MMT films exhibit high hardness, large elastic modulus, high elastic recovery, low friction, low scratch depth, and a smooth surface. When combined with the low oxygen permeability and high optical transmission of these thin films, these excellent mechanical properties make them good candidates for hard coating surface-sensitive substrates, where polymers are required to sustain long-term surface aesthetics and quality. PMID:27045231

  3. Safety philosophy of gas turbine high temperature reactor (GTHTR300)

    SciTech Connect

    Shoji Katanishi; Kazuhiko Kunitomi; Shusaku Shiozawa

    2002-07-01

    Japan Atomic Energy Research Institute (JAERI) has undertaken the study of an original design concept of gas turbine high temperature reactor, the GTHTR300. The general concept of this study is development of a greatly simplified design that leads to substantially reduced technical and cost requirements. Newly proposed design features enable the GTHTR300 to be an efficient and economically competitive reactor in 2010's. Also, the GTHTR300 fully takes advantage of its inherent safety characteristics. The safety philosophy of the GTHTR300 is developed based on the HTTR (High Temperature Engineering Test Reactor) of JAERI which is the first HTGR in Japan. Major features of the newly proposed safety philosophy for the GTHTR300 are described in this article. (authors)

  4. Smart Onboard Inspection of High Pressure Gas Fuel Cylinders

    SciTech Connect

    Beshears, D.L.; Starbuck, J.M.

    1999-09-27

    The use of natural gas as an alternative fuel in automotive applications is not widespread primarily because of the high cost and durability of the composite storage tanks. Tanks manufactured using carbon fiber are desirable in weight critical passenger vehicles because of the low density of carbon fiber. The high strength of carbon fiber also translates to a weight reduction because thinner wall designs are possible to withstand the internal pressure loads. However, carbon fiber composites are prone to impact damage that over the life of the storage tank may lead to an unsafe condition for the vehicle operator. A technique that potentially may be a reliable indication of developing hazardous conditions in composite fuel tanks is imbedded fiber optics. The applicability of this technique to onboard inspection is discussed and results from preliminary lab testing indicate that fiber optic sensors can reliably detect impact damage.

  5. Power Conversion Study for High Temperature Gas-Cooled Reactors

    SciTech Connect

    Chang Oh; Richard Moore; Robert Barner

    2005-05-01

    The Idaho National Laboratory (INL) is investigating a Brayton cycle efficiency improvement on a high temperature gas-cooled reactor (HTGR) as part of Generation-IV nuclear engineering research initiative. There are some technical issues to be resolved before the selection of the final design of the high temperature gascooled reactor, called as a Next Generation Nuclear Plant (NGNP), which is supposed to be built at the INEEL by year 2017. The technical issues are the selection of the working fluid, direct vs. indirect cycle, power cycle type, the optimized design in terms of a number of intercoolers, and others. In this paper, we investigated a number of working fluids for the power conversion loop, direct versus indirect cycle, the effect of intercoolers, and other thermal hydraulics issues. However, in this paper, we present part of the results we have obtained. HYSYS computer code was used along with a computer model developed using Visual Basic computer language.

  6. High-resolution methods for preserving the sum of mass fractions: improved χ-scheme and an alternative

    SciTech Connect

    Syamial, Madhava; Benyahia, Sofiane

    2013-11-20

    When high resolution convection schemes are used for discretizing chemical species mass balance equations, the mass fractions are not guaranteed to add to one. We show that a proposed remedy called χ-scheme (Darwish and Moukalled, Comput.Methods Appl.Mech. Engrg. 192 (2003): 1711) will degrade to a diffusive first-order scheme when a chemical species vanishes from the mixture, for example, because of chemical reactions. We propose an improvement to the χ-scheme to overcome this problem. Furthermore, a computationally efficient alternative scheme is proposed and evaluated with several examples, to quantify the improvements in the accuracy and the computational time.

  7. Protective efficacy of semi purified fraction of high altitude podophyllum hexandrum rhizomes in lethally irradiated Swiss albino mice.

    PubMed

    Gupta, M L; Tyagi, S; Flora, S J S; Agrawala, P K; Choudhary, P; Puri, S C; Sharma, A; Devi, M; Haksar, A; Qazi, G N; Tripathi, R P

    2007-05-30

    A fraction of high altitude Podophyllum hexandrum rhizome, REC-2006, was evaluated for its radioprotective efficacy against lethal gamma-irradiation (10 Gy, whole body) in Swiss albino mice. The maximum tolerated dose (MTD) and LD50 of this fraction were found to be 45 mg/kg b.w. and 74 mg/kg b.w. respectively. Pre-irradiation (- 2 h, ) administration (i.p.) of 6 or 8 mg/kg b.w. of REC-2006 rendered > 90% survival in lethally irradiated mice. The dose reduction factor was calculated to be 1.62 considering survival as the end point. REC-2006 treatment marked in significant increase in endogenous spleen colony forming units. In REC-2006 treated group, super oxide dismutase activity was increased significantly compared to the radiation control group (Liver, p = 0.00, Jejunum p = 0.00). The extract also inhibited radiation induced lipid peroxidation in liver (p = 0.00) at 24 h. REC-2006 administration (100-200 microg/ml) significantly reduced the halo diameter in mice thymocytes. Nearly 10 fold difference between the effective dose (6 mg/kg b.w.) and LD50 and the high degree of whole body survival (> 90% against 10 Gy irradiation) indicates REC-2006 to be safe and highly promising to achieve significant radioprotection against lethal radiation. Further purification and identification of active molecules and their efficacy studies in higher animals therefore demand attention.

  8. Hydrogen gettering the overpressure gas from highly radioactive liquids

    SciTech Connect

    Riley, D.L.; McCoy, J.C.; Schicker, J.R.

    1996-04-01

    Remediation of current inventories of high-activity radioactive liquid waste (HALW) requires transportation of Type-B quantities of radioactive material, possibly up to several hundred liters. However, the only currently certified packaging is limited to quantities of 50 ml (0.01 gal) quantities of Type-B radioactive liquid. Efforts are under way to recertify the existing packaging to allow the shipment of up to 4 L (1.1 gal) of Type-B quantities of HALW, but significantly larger packaging could be needed in the future. Scoping studies and preliminary designs have identified the feasibility of retrofitting an insert into existing casks, allowing the transport of up to 380 L (100 gal) of HALW. However, the insert design and ultimate certification strategy depend heavily on the gas-generating attributes of the HALW. A non-vented containment vessel filled with HALW, in the absence of any gas-mitigation technologies, poses a deflagration threat and, therefore, gas generation, specifically hydrogen generation, must be reliably controlled during all phases of transportation. Two techniques are available to mitigate hydrogen accumulation: recombiners and getters. Getters have an advantage over recombiners in that oxides are not required to react with the hydrogen. A test plan was developed to evaluate three forms of getter material in the presence of both simulated HALW and the gases that are produced by the HALW. These tests demonstrated that getters can react with hydrogen in the presence of simulated waste and in the presence of several other gases generated by the HALW, such as nitrogen, ammonia, nitrous oxide, and carbon monoxide. Although the use of such a gettering system has been shown to be technically feasible, only a preliminary design for its use has been completed. No further development is planned until the requirement for bulk transport of Type-B quantities of HALW is more thoroughly defined.

  9. Warm water deuterium fractionation in IRAS 16293-2422. The high-resolution ALMA and SMA view

    NASA Astrophysics Data System (ADS)

    Persson, M. V.; Jørgensen, J. K.; van Dishoeck, E. F.

    2013-01-01

    Context. Measuring the water deuterium fractionation in the inner warm regions of low-mass protostars has so far been hampered by poor angular resolution obtainable with single-dish ground- and space-based telescopes. Observations of water isotopologues using (sub)millimeter wavelength interferometers have the potential to shed light on this matter. Aims: To measure the water deuterium fractionation in the warm gas of the deeply-embedded protostellar binary IRAS 16293-2422. Methods: Observations toward IRAS 16293-2422 of the 53,2 - 44,1 transition of H218O at 692.07914 GHz from Atacama Large Millimeter/submillimeter Array (ALMA) as well as the 31,3 - 22,0 of H218O at 203.40752 GHz and the 31,2 - 22,1 transition of HDO at 225.89672 GHz from the Submillimeter Array (SMA) are presented. Results: The 692 GHz H218O line is seen toward both components of the binary protostar. Toward one of the components, "source B", the line is seen in absorption toward the continuum, slightly red-shifted from the systemic velocity, whereas emission is seen off-source at the systemic velocity. Toward the other component, "source A", the two HDO and H218O lines are detected as well with the SMA. From the H218O transitions the excitation temperature is estimated at 124 ± 12 K. The calculated HDO/H2O ratio is (9.2 ± 2.6) × 10-4 - significantly lower than previous estimates in the warm gas close to the source. It is also lower by a factor of ~5 than the ratio deduced in the outer envelope. Conclusions: Our observations reveal the physical and chemical structure of water vapor close to the protostars on solar-system scales. The red-shifted absorption detected toward source B is indicative of infall. The excitation temperature is consistent with the picture of water ice evaporation close to the protostar. The low HDO/H2O ratio deduced here suggests that the differences between the inner regions of the protostars and the Earth's oceans and comets are smaller than previously thought

  10. High pH reversed-phase chromatography with fraction concatenation for 2D proteomic analysis

    SciTech Connect

    Yang, Feng; Shen, Yufeng; Camp, David G.; Smith, Richard D.

    2012-04-01

    Orthogonal high-resolution separations are critical for attaining improved analytical dynamic ranges of proteome measurements. Concatenated high pH reversed phase liquid chromatography affords better separations than the strong cation exchange conventionally applied for two-dimensional shotgun proteomic analysis. For example, concatenated high pH reversed phase liquid chromatography increased identification coverage for peptides (e.g., by 1.8-fold) and proteins (e.g., by 1.6-fold) in shotgun proteomics analyses of a digested human protein sample. Additional advantages of concatenated high pH RPLC include improved protein sequence coverage, simplified sample processing, and reduced sample losses, making this an attractive first dimension separation strategy for two-dimensional proteomics analyses.

  11. High Altitude Aerial Natural Gas Leak Detection System

    SciTech Connect

    Richard T. Wainner; Mickey B. Frish; B. David Green; Matthew C. Laderer; Mark G. Allen; Joseph R. Morency

    2006-12-31

    The objective of this program was to develop and demonstrate a cost-effective and power-efficient advanced standoff sensing technology able to detect and quantify, from a high-altitude (> 10,000 ft) aircraft, natural gas leaking from a high-pressure pipeline. The advanced technology is based on an enhanced version of the Remote Methane Leak Detector (RMLD) platform developed previously by Physical Sciences Inc. (PSI). The RMLD combines a telecommunications-style diode laser, fiber-optic components, and low-cost DSP electronics with the well-understood principles of Wavelength Modulation Spectroscopy (WMS), to indicate the presence of natural gas located between the operator and a topographic target. The transceiver transmits a laser beam onto a topographic target and receives some of the laser light reflected by the target. The controller processes the received light signal to deduce the amount of methane in the laser's path. For use in the airborne platform, we modified three aspects of the RMLD, by: (1) inserting an Erbium-doped optical fiber laser amplifier to increase the transmitted laser power from 10 mW to 5W; (2) increasing the optical receiver diameter from 10 cm to 25 cm; and (3) altering the laser wavelength from 1653 nm to 1618 nm. The modified RMLD system provides a path-integrated methane concentration sensitivity {approx}5000 ppm-m, sufficient to detect the presence of a leak from a high capacity transmission line while discriminating against attenuation by ambient methane. In ground-based simulations of the aerial leak detection scenario, we demonstrated the ability to measure methane leaks within the laser beam path when it illuminates a topographic target 2000 m away. We also demonstrated simulated leak detection from ranges of 200 m using the 25 cm optical receiver without the fiber amplifier.

  12. Rapid differentiation of Ralstonia solanacearum avirulent and virulent strains by cell fractioning of an isolate using high performance liquid chromatography.

    PubMed

    Zheng, Xuefang; Zhu, Yujing; Liu, Bo; Yu, Qian; Lin, Naiquan

    2016-01-01

    Ralstonia solanacearum is one of the most destructive plant bacterial pathogens worldwide. The population dynamics and genetic stability are important issues, especially when an avirulent strain is used for biocontrol. In this study, we developed a rapid method to differentiate the virulent and avirulent strains of R. solanacearum and to predict the biocontrol efficiency of an avirulent strain using high performance liquid chromatography (HPLC). Three chromatographic peaks P1, P2 and P3 were observed on the HPLC spectra among 68 avirulent and 28 virulent R. solanacearum strains. Based on the HPLC peaks, 96 strains total were assigned to three categories. For avirulent strains, the intense peak is P1, while for virulent strains, P3 is the majority. Based on the HLPC spectra of R. solanacearum strains, a chromatography titer index (CTI) was established as CTIi = Si/(S1+S2+S3) × 100% (i represents an individual HPLC peak; S1, S2 and S3 represent peak areas of P1, P2 and P3, respectively). The avirulent strains had high values of CTI1 ranging from 63.6 to 100.0%, while the virulent strains displayed high values of CTI3 ranging from 90.2 to 100.0%. Biological inoculation studies of 68 avirulent strains revealed that the biocontrol efficacy was the best when CTI1 = 100%. The purity and genetic stability of R. solanacearum strains were confirmed in the P1 fraction of avirulent strain FJAT-1957 and P3 fraction of virulent strain FJAT-1925 after 30 generations of consecutive subculture. These results confirmed that fractioning by HPLC and their deduced CTI can be used for rapid and efficient evaluation and prediction of an isolate of R. solanacearum. To the best of our knowledge, this is the first report that HPLC fractioning can be used for rapid differentiation of virulent and avirulent strains of R. solanacearum. PMID:26606869

  13. Protective Effect of High Molecular Weight Protein Sub-fraction of Calotropis procera Latex in Monoarthritic Rats

    PubMed Central

    Chaudhary, Priyanka; Ramos, Marcio V.; Vasconcelos, Mirele da Silveira; Kumar, Vijay L.

    2016-01-01

    Background: Proteins present in the latex of Calotropis procera have been shown to produce anti-inflammatory effect and to afford protection in various disease models. Objectives: To determine the efficacy of high molecular weight protein sub-fraction (LPPI) of latex of C. procera in ameliorating joint inflammation and hyperalgesia in a preclinical model of arthritis. Materials and Methods: Monoarthritis was induced in rats by intra-articular injection of Freund's complete adjuvant (FCA) and the effect of two doses of LPPI (5 and 25 mg/kg) and diclofenac (5 mg/kg) was evaluated on joint swelling, stair climbing ability, motility, and dorsal flexion pain on day 3. The rats were sacrificed on day 3 to measure tissue levels of reduced glutathione (GSH) and thiobarbituric acid reactive substances (TBARS). Evaluation of joint histology was also made. Results: Intra-articular injection of FCA produced joint swelling and difficulty in stair climbing ability, motility, and pain on flexion of the joint as revealed by scores obtained for these functional parameters. LPPI produced a dose-dependent decrease in joint swelling and improved joint functions. Arthritic rats also revealed altered oxidative homeostasis where joint tissue GSH levels were decreased and TBARS levels were increased as compared to normal rats. The levels of these oxidative stress markers were near normal in arthritic rats treated with LPPI. Moreover, treatment with LPPI also maintained the structural integrity of the joint. The protective effect of LPPI was comparable to the standard anti-inflammatory drug, diclofenac. Conclusion: The findings of the present study show that LPPI fraction comprising high molecular weight proteins could be used for the alleviation of arthritic symptoms. SUMMARY High molecular weight protein sub-fraction of latex of Calotropis procera (LPPI) reduced joint swelling and hyperalgesia in arthritic ratsLPPI produced a significant improvement in stair climbing ability and motility

  14. Rapid differentiation of Ralstonia solanacearum avirulent and virulent strains by cell fractioning of an isolate using high performance liquid chromatography.

    PubMed

    Zheng, Xuefang; Zhu, Yujing; Liu, Bo; Yu, Qian; Lin, Naiquan

    2016-01-01

    Ralstonia solanacearum is one of the most destructive plant bacterial pathogens worldwide. The population dynamics and genetic stability are important issues, especially when an avirulent strain is used for biocontrol. In this study, we developed a rapid method to differentiate the virulent and avirulent strains of R. solanacearum and to predict the biocontrol efficiency of an avirulent strain using high performance liquid chromatography (HPLC). Three chromatographic peaks P1, P2 and P3 were observed on the HPLC spectra among 68 avirulent and 28 virulent R. solanacearum strains. Based on the HPLC peaks, 96 strains total were assigned to three categories. For avirulent strains, the intense peak is P1, while for virulent strains, P3 is the majority. Based on the HLPC spectra of R. solanacearum strains, a chromatography titer index (CTI) was established as CTIi = Si/(S1+S2+S3) × 100% (i represents an individual HPLC peak; S1, S2 and S3 represent peak areas of P1, P2 and P3, respectively). The avirulent strains had high values of CTI1 ranging from 63.6 to 100.0%, while the virulent strains displayed high values of CTI3 ranging from 90.2 to 100.0%. Biological inoculation studies of 68 avirulent strains revealed that the biocontrol efficacy was the best when CTI1 = 100%. The purity and genetic stability of R. solanacearum strains were confirmed in the P1 fraction of avirulent strain FJAT-1957 and P3 fraction of virulent strain FJAT-1925 after 30 generations of consecutive subculture. These results confirmed that fractioning by HPLC and their deduced CTI can be used for rapid and efficient evaluation and prediction of an isolate of R. solanacearum. To the best of our knowledge, this is the first report that HPLC fractioning can be used for rapid differentiation of virulent and avirulent strains of R. solanacearum.

  15. Carbon and hydrogen isotope fractionation under continuous light: implications for paleoenvironmental interpretations of the High Arctic during Paleogene warming.

    PubMed

    Yang, Hong; Pagani, Mark; Briggs, Derek E G; Equiza, M A; Jagels, Richard; Leng, Qin; Lepage, Ben A

    2009-06-01

    The effect of low intensity continuous light, e.g., in the High Arctic summer, on plant carbon and hydrogen isotope fractionations is unknown. We conducted greenhouse experiments to test the impact of light quantity and duration on both carbon and hydrogen isotope compositions of three deciduous conifers whose fossil counterparts were components of Paleogene Arctic floras: Metasequoia glyptostroboides, Taxodium distichum, and Larix laricina. We found that plant leaf bulk carbon isotopic values of the examined species were 1.75-4.63 per thousand more negative under continuous light (CL) than under diurnal light (DL). Hydrogen isotope values of leaf n-alkanes under continuous light conditions revealed a D-enriched hydrogen isotope composition of up to 40 per thousand higher than in diurnal light conditions. The isotope offsets between the two light regimes is explained by a higher ratio of intercellular to atmospheric CO(2) concentration (C (i)/C (a)) and more water loss for plants under continuous light conditions during a 24-h transpiration cycle. Apparent hydrogen isotope fractionations between source water and individual lipids (epsilon(lipid-water)) range from -62 per thousand (Metasequoia C(27) and C(29)) to -87 per thousand (Larix C(29)) in leaves under continuous light. We applied these hydrogen fractionation factors to hydrogen isotope compositions of in situ n-alkanes from well-preserved Paleogene deciduous conifer fossils from the Arctic region to estimate the deltaD value in ancient precipitation. Precipitation in the summer growing season yielded a deltaD of -186 per thousand for late Paleocene, -157 per thousand for early middle Eocene, and -182 per thousand for late middle Eocene. We propose that high-latitude summer precipitation in this region was supplemented by moisture derived from regionally recycled transpiration of the polar forests that grew during the Paleogene warming.

  16. Fractional randomness

    NASA Astrophysics Data System (ADS)

    Tapiero, Charles S.; Vallois, Pierre

    2016-11-01

    The premise of this paper is that a fractional probability distribution is based on fractional operators and the fractional (Hurst) index used that alters the classical setting of random variables. For example, a random variable defined by its density function might not have a fractional density function defined in its conventional sense. Practically, it implies that a distribution's granularity defined by a fractional kernel may have properties that differ due to the fractional index used and the fractional calculus applied to define it. The purpose of this paper is to consider an application of fractional calculus to define the fractional density function of a random variable. In addition, we provide and prove a number of results, defining the functional forms of these distributions as well as their existence. In particular, we define fractional probability distributions for increasing and decreasing functions that are right continuous. Examples are used to motivate the usefulness of a statistical approach to fractional calculus and its application to economic and financial problems. In conclusion, this paper is a preliminary attempt to construct statistical fractional models. Due to the breadth and the extent of such problems, this paper may be considered as an initial attempt to do so.

  17. Optical Measurement and Visualization in High-Pressure, High-Temperature, Aviation Gas Turbine Combustors

    NASA Technical Reports Server (NTRS)

    Hicks, Yolanda R.; Anderson, Robert C.; Locke, Randy J.

    2000-01-01

    Planar laser-induced fluorescence (PLIF), planar Mie scattering (PMie), and linear (1-D) spontaneous Raman scattering are applied to flame tube and sector combustors that burn Jet-A fuel at a range of inlet temperatures and pressures that simulate conditions expected in future high-performance civilian gas turbine engines. Chemiluminescence arising from C2 in the flame was also imaged. Flame spectral emissions measurements were obtained using a scanning spectrometer. Several different advanced concept fuel injectors were examined. First-ever PLIF and chemiluminescence data are presented from the 60-atm Gas turbine combustor facility.

  18. Principles of establishing material cycling with a high degree of closure in the experimental model of a BTLSS intended for a rated "fraction of a human"

    NASA Astrophysics Data System (ADS)

    Tikhomirov, Alexander A.; Ushakova, Sofya; Velichko, Vladimir; Tikhomirova, Natalia; Shikhov, Valentin; Trifonov, Sergey V.

    2016-07-01

    A promising way to develop future biotechnical life support systems (BTLSS) is to construct experimental models and establish the cycling intended for a fraction of a human. Being of relatively low cost, such models provide an opportunity to test effectively closed process that could be further transferred to the real BTLSS with humans. Researchers of the IBP SB RAS are developing an adequate BTLSS model with the loops closed to a high degree. To attain high closure of mass exchange processes, plants in the phototrophic compartment are cultivated under intensive lighting conditions, created by using modern LED irradiators of enhanced power, equipped with lens optics. The higher plant compartment has been renewed and broadened by including soybean plants, which improve the vegetable part of the human diet and make it more diverse. It is very important that the operation of the physicochemical installation for waste mineralization fully matches the composition of the atmosphere of plant growth chambers: the purified gaseous components of this installation enter the common atmosphere of the system, without causing any deviations from the norm in the gaseous composition. This proves the eco-friendliness of the developed physicochemical method of waste mineralization and shows that the gaseous components resulting from waste mineralization can be included in the system mass exchange. A system for including human respiration into the gas exchange of the BTLSS has been developed and tested; the associated gas exchange and water exchange dynamics have been analyzed. Results of the functioning of the experimental model of the BTLSS for several months are proposed for discussion in order to get insight into the formation of dynamic characteristics of cycling processes and factors determining them. The study was supported by the grant of the Russian Science Foundation (Project 14-14-00599) and carried out at the IBP SB RAS.

  19. High-Temperature Water-Gas Shift Membrane Reactor Study

    SciTech Connect

    Ciocco, M.V.; Iyoha, O.; Enick, R.M.; Killmeyer, R.P.

    2007-06-01

    NETL’s Office of Research and Development is exploring the integration of membrane reactors into coal gasification plants as a way of increasing efficiency and reducing costs. Water-Gas Shift Reaction experiments were conducted in membrane reactors at conditions similar to those encountered at the outlet of a coal gasifier. The changes in reactant conversion and product selectivity due to the removal of hydrogen via the membrane reactor were quantified. Research was conducted to determine the influence of residence time and H2S on CO conversion in both Pd and Pd80wt%Cu membrane reactors. Effects of the hydrogen sulfide-to-hydrogen ratio on palladium and a palladium-copper alloy at high-temperature were also investigated. These results were compared to thermodynamic calculations for the stability of palladium sulfides.

  20. High-voltage, low-inductance gas switch

    DOEpatents

    Gruner, Frederick R.; Stygar, William A.

    2016-03-22

    A low-inductance, air-insulated gas switch uses a de-enhanced annular trigger ring disposed between two opposing high voltage electrodes. The switch is DC chargeable to 200 kilovolts or more, triggerable, has low jitter (5 ns or less), has pre-fire and no-fire rates of no more than one in 10,000 shots, and has a lifetime of greater than 100,000 shots. Importantly, the switch also has a low inductance (less than 60 nH) and the ability to conduct currents with less than 100 ns rise times. The switch can be used with linear transformer drives or other pulsed-power systems.

  1. High Power Light Gas Helicon Plasma Source for VASIMR

    NASA Technical Reports Server (NTRS)

    Squire, Jared P.; Chang-Diaz, Franklin R.; Glover, Timothy W.; Jacobson, Verlin T.; Baity, F. Wally; Carter, Mark D.; Goulding, Richard H.

    2004-01-01

    In the Advanced Space Propulsion Laboratory (ASPL) helicon experiment (VX-10) we have measured a plasma flux to input gas rate ratio near 100% for both helium and deuterium at power levels up to 10 kW. Recent results at Oak Ridge National Laboratory (ORNL) show enhanced efficiency operation with a high power density, over 5 kW in a 5 cm diameter tube. Our helicon is presently 9 cm in diameter and operates up to 10 kW of input power. The data here uses a Boswell double-saddle antenna design with a magnetic cusp just upstream of the antenna. Similar to ORNL, for deuterium at near 10 kW, we find an enhanced performance of operation at magnetic fields above the lower hybrid matching condition.

  2. Fractionation of CO in the diffuse clouds toward Zeta Ophiuchi

    NASA Technical Reports Server (NTRS)

    Sheffer, Yaron; Federman, S. R.; Lambert, David L.; Cardelli, Jason A.

    1992-01-01

    An analysis of CO A-X bands in diffuse clouds toward Zeta Ophiuchi is presented. The results provide isotopic ratios that constitute the strongest observational evidence for highly localized isotopic fractionation of CO in diffuse portions of an interstellar cloud. The value of the fractionation implies that selective photodissociation is the controlling influence of the fractionation. The molecule's excitation temperature is discussed and a lower limit to the O-16/O-18 ratio is provided. The absence of CO lines from the gas that provides broad CH+ and CH lines commonly attributed to warm gas behind a shock front is addressed.

  3. Inter-element fractionation of highly siderophile elements in the Tonga Arc due to flux melting of a depleted source

    NASA Astrophysics Data System (ADS)

    Dale, Christopher W.; Macpherson, Colin G.; Pearson, D. Graham; Hammond, Samantha J.; Arculus, Richard J.

    2012-07-01

    Highly siderophile element concentrations (HSEs: Os, Ir, Ru, Pt, Pd, and Re) have been determined for a suite of fresh, submarine mafic lavas from the northern Tonga Arc front and the nascent backarc Fonualei Spreading Centre (FSC). Prior melt depletion of the Tongan mantle wedge combined with a high degree of fluid fluxed melting is thought to have produced boninitic magmas at several arc and FSC locations. As such, this arc system provides an opportunity to assess the fluid mobility of HSEs and to investigate the effects of fluid-induced melting and prior melt depletion on HSE behaviour during both mantle melting and magma evolution. Tongan lavas display extreme enrichment of Pt (2.5-32 ng/g) and Pd over Os (0.002-0.6 ng/g), Ir, and Ru, significantly greater than basalts from mid-ocean ridges. Magma evolution increases the degree of fractionation, resulting in the highest recorded Pt/Ru ratios (>300) in arc front samples with MgO <8 wt.%. This increasing fractionation is due to the mild incompatibility of Pt and Pd, and concurrent compatibility of Ru, during sulphide undersaturated magma evolution. However, the fractionation of Pt and Pd from Os, Ir, and Ru is observed in the highest MgO samples, indicating source inheritance. Prior melt depletion of the mantle and elevated oxygen fugacity both increase the likelihood of complete consumption of sulphide in the source during melting, which typically leads to melts with high concentrations of all the HSE. Indeed, modelling indicates that 25% aggregate partial melting of a depleted MORB-mantle source, proposed for the Tonga Arc, will lead to complete base-metal sulphide consumption unless there is considerable addition of S by the slab flux (at least 200 μg/g). Although source enrichment of Pt, Pd, and Re by slab fluids may take place, the fractionation of Pt and Pd from Os, Ir, and Ru can largely be explained by relatively low-temperature, yet high-degree, melting of fluid-fluxed melt-depleted mantle. The high Pt

  4. M dwarfs and the fraction of high carbon-to-oxygen stars in the solar neighbourhood

    NASA Astrophysics Data System (ADS)

    Gizis, John E.; Marks, Zachary; Hauschildt, Peter H.

    2016-02-01

    We investigate the frequency of high carbon-to-oxygen (C/O = 0.9) M dwarf stars in the solar neighbourhood. Using synthetic spectra, we find that such M dwarfs would have weaker TiO bands relative to hydride features. Similar weakening has already been detected in M-subdwarf (sdM) stars. By comparing to existing spectroscopic surveys of nearby stars, we show that less than one per cent of nearby stars have high carbon-to-oxygen ratios. This limit does not include stars with C/O = 0.9, [m/H] > 0.3, and [C/Fe] > 0.1, which we predict to have low-resolution optical spectra similar to solar metallicity M dwarfs.

  5. Characterization of the metal particles fraction in ceramic matrix composites fabricated under high pressure

    SciTech Connect

    Konopka, K. . E-mail: Kako@inmat.pw.edu.pl; Bucki, J.J.; Gierlotka, S.; Kurzydlowski, K.J.

    2006-06-15

    This paper presents preliminary results concerning Al{sub 2}O{sub 3}-Ni composites fabricated by sintering under a high pressure of 7.7 GPa, at a temperature below the melting temperature of nickel. The microstructure of composites was characterized by scanning and transmission electron microscopy. Quantitative measurements of size, shape and distribution of metal particles were based on image analysis. A correlation between the size of the Ni particles and their location has been found. Small Ni particles, with a grain size in the range of 50-500 nm, are mostly located inside the ceramic grains. Some Ni particles are also situated at the grain boundaries, and large particles are surrounded by ceramic grains. The shape of the ceramic grains suggests that the ceramic powder particles underwent deformation during the process of consolidation under high pressure.

  6. High severity pyrolysis of shale and petroleum gas oil mixtures

    SciTech Connect

    Leftin, H.P.; Newsome, D.S.

    1986-01-01

    Light gas oil and heavy gas oil from Paraho shale oil and their mixtures with a petroleum light gas oil were pyrolyzed in the presence of steam at 880-900/sup 0/C and contact times between 60 and 90 ms in a nonisothermal bench-scale pyrolysis reactor. Blending of petroleum LGO into the shale oil feeds provided product yields that were the weighted linear combination of the yields of the individual components of the blends. Partial denitrogenation and a pronounced decrease in the rate of coke deposition on the reactor walls were observed when petroleum gas oil was blended with the shale gas oils.

  7. High-Temperature Gas Sensor Array (Electronic Nose) Demonstrated

    NASA Technical Reports Server (NTRS)

    Hunter, Gary W.

    2002-01-01

    The ability to measure emissions from aeronautic engines and in commercial applications such as automotive emission control and chemical process monitoring is a necessary first step if one is going to actively control those emissions. One single sensor will not give all the information necessary to determine the chemical composition of a high-temperature, harsh environment. Rather, an array of gas sensor arrays--in effect, a high-temperature electronic "nose"--is necessary to characterize the chemical constituents of a diverse, high-temperature environment, such as an emissions stream. The signals produced by this nose could be analyzed to determine the constituents of the emission stream. Although commercial electronic noses for near-room temperature applications exist, they often depend significantly on lower temperature materials or only one sensor type. A separate development effort necessary for a high-temperature electronic nose is being undertaken by the NASA Glenn Research Center, Case Western Reserve University, Ohio State University, and Makel Engineering, Inc. The sensors are specially designed for hightemperature environments. A first-generation high-temperature electronic nose has been demonstrated on a modified automotive engine. This nose sensor array was composed of sensors designed for hightemperature environments fabricated using microelectromechanical-systems- (MEMS-) based technology. The array included a tin-oxide-based sensor doped for nitrogen oxide (NOx) sensitivity, a SiC-based hydrocarbon (CxHy) sensor, and an oxygen sensor (O2). These sensors operate on different principles--resistor, diode, and electrochemical cell, respectively--and each sensor has very different responses to the individual gases in the environment. A picture showing the sensor head for the array is shown in the photograph on the left and the sensors installed in the engine are shown in the photograph on the right. Electronics are interfaced with the sensors for

  8. Accumulated metal speciation in earthworm populations with multigenerational exposure to metalliferous soils: cell fractionation and high-energy synchrotron analyses.

    PubMed

    Andre, Jane; Charnock, John; Stürzenbaum, Stephen R; Kille, Peter; Morgan, A John; Hodson, Mark E

    2009-09-01

    Predicting metal bioaccumulation and toxicity in soil organisms is complicated by site-specific biotic and abiotic parameters. In this study we exploited tissue fractionation and digestion techniques, combined with X-ray absorption spectroscopy (XAS), to investigate the whole-body and subcellular distributions, ligand affinities, and coordination chemistry of accumulated Pb and Zn in field populations of the epigeic earthworm Lumbricus rubellus inhabiting three contrasting metalliferous and two unpolluted soils. Our main findings were (i) earthworms were resident in soils with concentrations of Pb and Zn ranging from 1200 to 27,000 mg kg(-1) and 200 to 34,000 mg kg(-1), respectively; (ii) Pb and Zn primarily accumulated in the posterior alimentary canal in nonsoluble subcellular fractions of earthworms; (iii) site-specific differences in the tissue and subcellular partitioning profiles of populations were observed, with earthworms from a calcareous site partitioning proportionally more Pb to their anterior body segments and Zn to the chloragosome-rich subcellular fraction than their acidic-soil inhabiting counterparts; (iv) XAS indicated that the interpopulation differences in metal partitioning between organs were not accompanied by qualitative differences in ligand-binding speciation, because crystalline phosphate-containing pyromorphite was a predominant chemical species in the whole-worm tissues of all mine soil residents. Differences in metal (Pb, Zn) partitioning at both organ and cellular levels displayed by field populations with protracted histories of metal exposures may reflect theirinnate ecophysiological responses to essential edaphic variables, such as Ca2+ status. These observations are highly significant in the challenging exercise of interpreting holistic biomarker data delivered by "omic" technologies. PMID:19764255

  9. Experimental observation of fractional echoes

    NASA Astrophysics Data System (ADS)

    Karras, G.; Hertz, E.; Billard, F.; Lavorel, B.; Siour, G.; Hartmann, J.-M.; Faucher, O.; Gershnabel, Erez; Prior, Yehiam; Averbukh, Ilya Sh.

    2016-09-01

    We report the observation of fractional echoes in a double-pulse excited nonlinear system. Unlike standard echoes, which appear periodically at delays which are integer multiples of the delay between the two exciting pulses, the fractional echoes appear at rational fractions of this delay. We discuss the mechanism leading to this phenomenon, and provide experimental demonstration of fractional echoes by measuring third harmonic generation in a thermal gas of CO2 molecules excited by a pair of femtosecond laser pulses.

  10. Physical Characterization of Solid-Liquid Slurries at High Weight Fractions Using Optical and Ultrasonic Methods

    SciTech Connect

    Burgess, L.W.; Brodsky, A.M.; Panetta P.D.

    2005-12-22

    Remediation of highly radioactive waste is a major technical and programmatic challenge for the DOE. Rapid, on-line physical characterization of highly concentrated slurries is required for the safe and efficient remediation of 90 million gallons of high level radioactive waste (HLW), sodium bearing waste, and mixed waste. The research presented here, describes a collaborative effort between Pacific Northwest National Laboratory (PNNL) and the University of Washington (UW) to directly address the need for rapid on-line characterization of the physical properties of HLW slurries during all phases of the remediation process, from in-tank characterization of sediments to monitoring of the concentration, particle size, and degree of agglomeration and gelation of slurries during transport. Near-surface characterization of the slurry flow in the particle size range from nanometer to micrometer is examined using optical low coherence reflectometry. Volumetric characterization at depths in the slurry flow, up to several centimeters in the particle size range from the micrometer to millimeter, is realized by utilizing ultrasonic backscatter and diffuses fields. One of the strengths, the teaming up of significant talents in both experimental and theoretical optics and in ultrasonics, provides a synergistic approach to integrate these complimentary techniques. One of the benefits of this combined approach is the physical characterization of HLW over a concentration and particle size range that is broader than can be achieved with today's technology. This will avoid a costly increase in waste stream volume due to excess dilution, and will lessen chance of plugging pipes that could shut down expensive processing lines.

  11. A high yield technique for freeze-fracturing of small fractions of isolated cells.

    PubMed

    Falcieri, E; Mariani, A R; Del Coco, R; Facchini, A; Maraldi, N M

    1988-07-01

    A simple, high-yield technique for the freeze-fracturing of small amounts of isolated cells is described. A drop of cells fixed in suspension is deposited on a polylysine-treated coverslip, forming a monolayer through electrostatic forces. After cryoprotection, the coverslip is inverted on a gold carrier covered with Vinol and then frozen in liquid nitrogen. The monolayer will be fractured by advancing the knife under the coverslip. Large areas of cell surface can be exposed despite their low number, such as that obtainable after cell sorting by flow cytometry. PMID:3179998

  12. INTERMEDIATE-VELOCITY MOLECULAR GAS AT HIGH NORTHERN GALACTIC LATITUDES

    SciTech Connect

    Magnani, Loris; Smith, Allison J.

    2010-10-20

    We surveyed the CO(1-0) transition in 16 regions at Galactic latitudes >45{sup 0} which contain compact dust cores less than half a degree in size with E(B - V) values {approx} 0.1 mag. We discovered three new intermediate-velocity molecular clouds and two high-latitude molecular clouds with more typical local standard of rest velocity ({approx}0 km s{sup -1}). The three intermediate-velocity molecular clouds (detected in CO emission in 11 lines of sight) nearly double the number of previously known, CO-emitting clouds. In order to detect the CO(1-0) line, N(H{sub 2}) values of at least 10{sup 19} cm{sup -2} are necessary, implying that the molecular/atomic fraction of these objects is significant and is in contrast to the primarily atomic lines of sight with log N(H{sub 2}) < 17.3 detected in absorption by FUSE. The three molecular clouds are projected on and likely associated with a previously known intermediate-velocity H I feature known as the Intermediate Velocity Spur that may extend to the Galactic halo.

  13. High Power Light Gas Helicon Plasma Source For VASMIR

    NASA Technical Reports Server (NTRS)

    Squire, J. P.; Chang-Diaz, F. R.; Glover, T. W.; Jacobson, V. T.; McCaskill, G. E.; Winter, D. S.; Baity, F. W.; Carter, M. D.; Goulding, R. H.

    2004-01-01

    The VASIMR space propulsion development effort relies on a high power (greater than 10kW) helicon source to produce a dense flowing plasma (H, D and He) target for ion cyclotron resonance (ICR) acceleration of the ions. Subsequent expansion in an expanding magnetic field (magnetic nozzle) converts ion lunetic energy to directed momentum. This plasma source must have critical features to enable an effective propulsion device. First, it must ionize most of the input neutral flux of gas, thus producing a plasma stream with a high degree of ionization for application of ICR power. This avoids propellant waste and potential power losses due to charge exchange. Next, the plasma stream must flow into a region of high magnetic field (approximately 0.5 T) for efficient ICR acceleration. Third, the ratio of input power to plasma flux must be low, providing an energy per ion-electron pair approaching 100 eV. Lastly, the source must be robust and capable of very long life-times (years). In our helicon experiment (VX-10) we have measured a ratio of input gas to plasma flux near 100%. The plasma flows from the helicon region (B approximately 0.1 T) into a region with a peak magnetic field of 0.8 T. The energy input per ion-electron pair has been measured at 300 plus or minus 100 eV. Recent results at Oak Ridge National Laboratory (ORNL) show an enhanced efficiency mode of operation with a high power density, over 5 kW in a 5 cm diameter tube. Our helicon is presently 9 cm in diameter and operates up to 3.5 kW of input power. An upgrade to a power level of 10 kW is underway. Much of our recent work has been with a Boswell double-saddle antenna design. We are also converting the antenna design to a helical type. With these modifications, we anticipate an improvement in the ionization efficiency. This paper presents the results from scaling the helicon in the VX-10 device from 3.5 to 10 kW. We also compare the operation with a double-saddle to a helical antenna design. Finally, we

  14. NiAl-Base Composite Containing High Volume Fraction of AIN Particulate for Advanced Engines

    NASA Technical Reports Server (NTRS)

    Hebsur, Mohan G.; Whittenberger, J. D.; Lowell, C. E.; Garg, A.

    1995-01-01

    Cryomilling of prealloyed NiAl containing 53 at. % AJ was carried out to achieve high nitrogen levels. The consolidation of cryomilled powder by extrusion or hot pressing/ hot isostatic pressing resulted in a fully dense NiAl-base composite containing 30 vol. % of inhomogeneously distributed, nanosized AIN particulate. The NiAl-30AIN composite exhibited the highest compression yield strengths at all temperatures between 300 and 1300 K as compared with other compositions of NiAl-AIN composite. The NiAl-30AIN specimens tested under compressive creep loading between 1300 and 1500 K also exhibited the highest creep resistance with very little surface oxidation indicating also their superior elevated temperature oxidation resistance. In the high stress exponent regime, the strength is proportional to the square root of the AIN content and in the low stress exponent regime, the influence of AIN content on strength appears to be less dramatic. The specific creep strength of this material at 1300 K is superior to a first generation Ni-base single crystal superalloy. The improvements in elevated temperature creep strength and oxidation resistance have been achieved without sacrificing the room temperature fracture toughness of the NiAl-base material. Based on its attractive combination of properties, the NiAl-30AIN composite is a potential candidate for advanced engine applications,

  15. Thermal Hydraulics of the Very High Temperature Gas Cooled Reactor

    SciTech Connect

    Chang Oh; Eung Kim; Richard Schultz; Mike Patterson; Davie Petti

    2009-10-01

    The U.S Department of Energy (DOE) is conducting research on the Very High Temperature Reactor (VHTR) design concept for the Next Generation Nuclear Plant (NGNP) Project. The reactor design will be a graphite moderated, thermal neutron spectrum reactor that will produce electricity and hydrogen in a highly efficient manner. The NGNP reactor core will be either a prismatic graphite block type core or a pebble bed core. The NGNP will use very high-burnup, low-enriched uranium, TRISO-coated fuel, and have a projected plant design service life of 60 years. The VHTR concept is considered to be the nearest-term reactor design that has the capability to efficiently produce hydrogen. The plant size, reactor thermal power, and core configuration will ensure passive decay heat removal without fuel damage or radioactive material releases during reactor core-accidents. The objectives of the NGNP Project are to: Demonstrate a full-scale prototype VHTR that is commercially licensed by the U.S. Nuclear Regulatory Commission, and Demonstrate safe and economical nuclear-assisted production of hydrogen and electricity. The DOE laboratories, led by the INL, perform research and development (R&D) that will be critical to the success of the NGNP, primarily in the areas of: • High temperature gas reactor fuels behavior • High temperature materials qualification • Design methods development and validation • Hydrogen production technologies • Energy conversion. This paper presents current R&D work that addresses fundamental thermal hydraulics issues that are relevant to a variety of possible NGNP designs.

  16. Mass spectrometric gas composition measurements associated with jet interaction tests in a high-enthalpy wind tunnel

    NASA Technical Reports Server (NTRS)

    Lewis, B. W.; Brown, K. G.; Wood, G. M., Jr.; Puster, R. L.; Paulin, P. A.; Fishel, C. E.; Ellerbe, D. A.

    1986-01-01

    Knowledge of test gas composition is important in wind-tunnel experiments measuring aerothermodynamic interactions. This paper describes measurements made by sampling the top of the test section during runs of the Langley 7-Inch High-Temperature Tunnel. The tests were conducted to determine the mixing of gas injected from a flat-plate model into a combustion-heated hypervelocity test stream and to monitor the CO2 produced in the combustion. The Mass Spectrometric (MS) measurements yield the mole fraction of N2 or He and CO2 reaching the sample inlets. The data obtained for several tunnel run conditions are related to the pressures measured in the tunnel test section and at the MS ionizer inlet. The apparent distributions of injected gas species and tunnel gas (CO2) are discussed relative to the sampling techniques. The measurements provided significant real-time data for the distribution of injected gases in the test section. The jet N2 diffused readily from the test stream, but the jet He was mostly entrained. The amounts of CO2 and Ar diffusing upward in the test section for several run conditions indicated the variability of the combustion-gas test-stream composition.

  17. Bi-Component T2* Analysis of Bound and Pore Bone Water Fractions Fails at High Field Strengths

    PubMed Central

    Seifert, Alan C.; Wehrli, Suzanne L.; Wehrli, Felix W.

    2015-01-01

    Osteoporosis involves degradation of bone’s trabecular architecture, cortical thinning, and enlargement of cortical pores. Increased cortical porosity is a major cause of the decreased strength of osteoporotic bone. The majority of cortical pores, however, are below the resolution limit of MRI. Recent work has shown that porosity can be evaluated by MRI-based quantification of bone water. Bi-exponential T2* fitting and adiabatic inversion preparation are the two most common methods purported to distinguish bound and pore water in order to quantify matrix density and porosity. To assess the viability of T2* bi-component analysis as a method for quantifying bound and pore water fractions, we have applied this method to human cortical bone at 1.5T, 3T, 7T, and 9.4T, and validated the resulting pool fractions against μCT-derived porosity and gravimetrically-determined bone densities. We also investigated alternative methods: 2D T1–T2* bi-component fitting by incorporating saturation-recovery, 1D and 2D fitting of CPMG echo amplitudes, and deuterium inversion recovery. Short-T2* pool fraction was moderately correlated with porosity (R2 = 0.70) and matrix density (R2 = 0.63) at 1.5T, but the strengths of these associations were found to diminish rapidly as field strength increases, falling below R2 = 0.5 at 3T. Addition of the T1 dimension to bi-component analysis only slightly improved the strengths of these correlations. T2*-based bi-component analysis should therefore be used with caution. Performance of deuterium inversion-recovery at 9.4T was also poor (R2 = 0.50 versus porosity and R2 = 0.46 versus matrix density). CPMG-derived short-T2 fraction at 9.4T, however, is highly correlated with porosity (R2 = 0.87) and matrix density (R2 = 0.88), confirming the utility of this method for independent validation of bone water pools. PMID:25981785

  18. On-line hyphenation of centrifugal partition chromatography and high pressure liquid chromatography for the fractionation of flavonoids from Hippophaë rhamnoides L. berries.

    PubMed

    Michel, Thomas; Destandau, Emilie; Elfakir, Claire

    2011-09-01

    Centrifugal Partition Chromatography (CPC), a liquid-liquid preparative chromatography using two immiscible solvent systems, benefits from numerous advantages for the separation or purification of synthetic or natural products. This study presents the on-line hyphenation of CPC-Evaporative Light Scattering Detector (CPC-ELSD) with High Performance Liquid Chromatography-UV (HPLC-UV) for the fractionation of flavonols from a solvent-free microwave extract of sea buckthorn (Hippophaë rhamnoides L., Elaeagnaceae) berries. An Arizona G system was used for the fractionation of flavonoids by CPC and a fused core Halo C18 column allowed the on-line analyses of collected fractions by HPLC. The on-line CPC/HPLC procedure allowed the simultaneous fractionation step at preparative scale combined with the HPLC analyses which provide direct fingerprint of collected fractions. Thus the crude extract was simplified and immediate information on the composition of fractions could be obtained. Furthermore, this methodology reduced the time of post-fractionation steps and facilitated identification of main molecules by Mass Spectrometry (MS). Rutin, isorhamnetin-3-O-rutinoside, isorhamnetin-3-O-glucoside, quercetin-3-O-glucoside, isorhamnetin-rhamnoside, quercetin and isorhamnetin were identified. CPC-ELSD/HPLC-UV could be considered as a high-throughput technique for the guided fractionation of bioactive natural products from complex crude extracts.

  19. Highly dealuminated Y zeolite as efficient adsorbent for the hydrophobic fraction from wastewater treatment plants effluents.

    PubMed

    Navalon, Sergio; Alvaro, Mercedes; Garcia, Hermenegildo

    2009-07-15

    In this work we report that highly dealuminated zeolite Y is a hydrophobic material that is able to remove selectively fatty acids and hydrocarbon compounds from the effluent of an urban wastewater treatment plant (UWTP). This adsorbent capability of zeolite Y could lead to an improved quality of UWTP effluents. Typical domestic wastewaters contain detergents, soaps and surfactants that are only partially removed in conventional UWTP. In the present work using an effluent from a UWTP located at Ribarroja del Turia (Valencia, Spain) containing 10 ppm of total organic carbon, we have been able to retain by adsorption on the dealuminated Y zeolite up to 16 and 60% of the organic matter of the effluent at pH values 7.2 and 4, respectively. Characterization of the adsorbed organic matter by Fourier transformed infrared (FT-IR), (1)H NMR and GC-MS after derivatization has shown that the zeolite adsorbs selectively the hydrophobic compounds of the effluent.

  20. InGaN nanowires with high InN molar fraction: growth, structural and optical properties.

    PubMed

    Zhang, Xin; Lourenço-Martins, Hugo; Meuret, Sophie; Kociak, Mathieu; Haas, Benedikt; Rouvière, Jean-Luc; Jouneau, Pierre-Henri; Bougerol, Catherine; Auzelle, T; Jalabert, D; Biquard, Xavier; Gayral, Bruno; Daudin, Bruno

    2016-05-13

    The structural and optical properties of axial GaN/InGaN/GaN nanowire heterostructures with high InN molar fractions grown by molecular beam epitaxy have been studied at the nanoscale by a combination of electron microscopy, extended x-ray absorption fine structure and nano-cathodoluminescence techniques. InN molar fractions up to 50% have been successfully incorporated without extended defects, as evidence of nanowire potentialities for practical device realisation in such a composition range. Taking advantage of the N-polarity of the self-nucleated GaN NWs grown by molecular beam epitaxy on Si(111), the N-polar InGaN stability temperature diagram has been experimentally determined and found to extend to a higher temperature than its metal-polar counterpart. Furthermore, annealing of GaN-capped InGaN NWs up to 800 °C has been found to result in a 20 times increase of photoluminescence intensity, which is assigned to point defect curing.

  1. Terrestrial planets in high-mass disks without gas giants

    NASA Astrophysics Data System (ADS)

    de Elía, G. C.; Guilera, O. M.; Brunini, A.

    2013-09-01

    Context. Observational and theoretical studies suggest that planetary systems consisting only of rocky planets are probably the most common in the Universe. Aims: We study the potential habitability of planets formed in high-mass disks without gas giants around solar-type stars. These systems are interesting because they are likely to harbor super-Earths or Neptune-mass planets on wide orbits, which one should be able to detect with the microlensing technique. Methods: First, a semi-analytical model was used to define the mass of the protoplanetary disks that produce Earth-like planets, super-Earths, or mini-Neptunes, but not gas giants. Using mean values for the parameters that describe a disk and its evolution, we infer that disks with masses lower than 0.15 M⊙ are unable to form gas giants. Then, that semi-analytical model was used to describe the evolution of embryos and planetesimals during the gaseous phase for a given disk. Thus, initial conditions were obtained to perform N-body simulations of planetary accretion. We studied disks of 0.1, 0.125, and 0.15 M⊙. Results: All our simulations form massive planets on wide orbits. For a 0.1 M⊙ disk, 2-3 super-Earths of 2.8 to 5.9 M⊕ are formed between 2 and 5 AU. For disks of 0.125 and 0.15 M⊙, our simulations produce a 10-17.1 M⊕ planet between 1.6 and 2.7 AU, and other super-Earths are formed in outer regions. Moreover, six planets survive in the habitable zone (HZ). These planets have masses from 1.9 to 4.7 M⊕ and significant water contents ranging from 560 to 7482 Earth oceans, where one Earth ocean represents the amount of water on Earth's surface, which equals 2.8 × 10-4M⊕. Of the six planets formed in the HZ, three are water worlds with 39%-44% water by mass. These planets start the simulations beyond the snow line, which explains their high water abundances. In general terms, the smaller the mass of the planets observed on wide orbits, the higher the possibility to find water worlds in the

  2. A high ozone episode in winter 2013 in the Uinta Basin oil and gas region characterized by aircraft measurements

    NASA Astrophysics Data System (ADS)

    Oltmans, S. J.; Karion, A.; Schnell, R. C.; Pétron, G.; Sweeney, C.; Wolter, S.; Neff, D.; Montzka, S. A.; Miller, B. R.; Helmig, D.; Johnson, B. J.; Hueber, J.

    2014-08-01

    During the winter of 2012-2013 atmospheric surface ozone mole fractions exceeded the US 8 h standard of 75 ppb on 39 days in the Uinta Basin of Utah. As part of the Uinta Basin Winter Ozone Study (UBWOS) aircraft flights were conducted throughout the basin with continuous measurements of ozone (O3), methane (CH4), carbon dioxide (CO2), carbon monoxide (CO), nitrogen dioxide (NO2), and discrete whole air flask samples for determination of ∼50 trace gases including a number of non-methane hydrocarbons (NMHCs). During the course of seven flights conducted between 31 January and 7 February 2013, coinciding with strong, multi-day temperature inversions, O3 levels gradually built up in the shallow boundary layer from ∼45 ppb to ∼140 ppb. Near-surface CH4 mole fractions increased during the episode from near background levels of ∼2 ppm to over 10 ppm. Based on elevated levels of CH4 across the basin and high correlations of CH4 with NMHCs from the discrete air samples, O3 precursor NMHCs were also inferred to be elevated throughout the basin. Discrete plumes of high NO2 were observed in the gas production region of the basin suggesting that gas processing plants and compressor facilities were important point sources of reactive nitrogen oxides (NOx). Vertical profiles obtained during the flights showed that the high O3 mole fractions (as well as other elevated constituents) were confined to a shallow layer from near the ground to 300-400 m above ground level (m a.g.l.) capped by a strong temperature inversion. The highest mole fractions of the measured constituents during the study period were in an isothermal cold layer that varied from ∼300 m depth on 4 February to ∼150 m on 5 February. A gradient layer with declining mole fractions with altitude extended above the isothermal layer to ∼1900 m a.s.l. (300-400 m a.g.l.) indicative of some mixing of air out of the boundary layer. O3 mole fractions continued to increase within the basin as the

  3. Graphene nanomesh as highly sensitive chemiresistor gas sensor.

    PubMed

    Paul, Rajat Kanti; Badhulika, Sushmee; Saucedo, Nuvia M; Mulchandani, Ashok

    2012-10-01

    Graphene is a one atom thick carbon allotrope with all surface atoms that has attracted significant attention as a promising material as the conduction channel of a field-effect transistor and chemical field-effect transistor sensors. However, the zero bandgap of semimetal graphene still limits its application for these devices. In this work, ethanol-chemical vapor deposition (CVD) of a grown p-type semiconducting large-area monolayer graphene film was patterned into a nanomesh by the combination of nanosphere lithography and reactive ion etching and evaluated as a field-effect transistor and chemiresistor gas sensors. The resulting neck-width of the synthesized nanomesh was about ∼20 nm and was comprised of the gap between polystyrene (PS) spheres that was formed during the reactive ion etching (RIE) process. The neck-width and the periodicities of the graphene nanomesh (GNM) could be easily controlled depending on the duration/power of the RIE and the size of the PS nanospheres. The fabricated GNM transistor device exhibited promising electronic properties featuring a high drive current and an I(ON)/I(OFF) ratio of about 6, significantly higher than its film counterpart. Similarly, when applied as a chemiresistor gas sensor at room temperature, the graphene nanomesh sensor showed excellent sensitivity toward NO(2) and NH(3), significantly higher than their film counterparts. The ethanol-based graphene nanomesh sensors exhibited sensitivities of about 4.32%/ppm in NO(2) and 0.71%/ppm in NH(3) with limits of detection of 15 and 160 ppb, respectively. Our demonstrated studies on controlling the neck width of the nanomesh would lead to further improvement of graphene-based transistors and sensors.

  4. Graphene nanomesh as highly sensitive chemiresistor gas sensor.

    PubMed

    Paul, Rajat Kanti; Badhulika, Sushmee; Saucedo, Nuvia M; Mulchandani, Ashok

    2012-10-01

    Graphene is a one atom thick carbon allotrope with all surface atoms that has attracted significant attention as a promising material as the conduction channel of a field-effect transistor and chemical field-effect transistor sensors. However, the zero bandgap of semimetal graphene still limits its application for these devices. In this work, ethanol-chemical vapor deposition (CVD) of a grown p-type semiconducting large-area monolayer graphene film was patterned into a nanomesh by the combination of nanosphere lithography and reactive ion etching and evaluated as a field-effect transistor and chemiresistor gas sensors. The resulting neck-width of the synthesized nanomesh was about ∼20 nm and was comprised of the gap between polystyrene (PS) spheres that was formed during the reactive ion etching (RIE) process. The neck-width and the periodicities of the graphene nanomesh (GNM) could be easily controlled depending on the duration/power of the RIE and the size of the PS nanospheres. The fabricated GNM transistor device exhibited promising electronic properties featuring a high drive current and an I(ON)/I(OFF) ratio of about 6, significantly higher than its film counterpart. Similarly, when applied as a chemiresistor gas sensor at room temperature, the graphene nanomesh sensor showed excellent sensitivity toward NO(2) and NH(3), significantly higher than their film counterparts. The ethanol-based graphene nanomesh sensors exhibited sensitivities of about 4.32%/ppm in NO(2) and 0.71%/ppm in NH(3) with limits of detection of 15 and 160 ppb, respectively. Our demonstrated studies on controlling the neck width of the nanomesh would lead to further improvement of graphene-based transistors and sensors. PMID:22931286

  5. Graphene nanomesh as highly sensitive chemiresistor gas sensor

    PubMed Central

    Paul, Rajat Kanti; Badhulika, Sushmee; Saucedo, Nuvia M.; Mulchandani, Ashok

    2016-01-01

    Graphene is a one atom thick carbon allotrope with all surface atoms that has attracted significant attention as a promising material as the conduction channel of a field-effect transistor and chemical field-effect transistor sensors. However, the zero bandgap of semimetal graphene still limits its application for these devices. In this work, ethanol-chemical vapor deposition (CVD) grown p-type semiconducting large-area monolayer graphene film was patterned into nanomesh by the combination of nanosphere lithography and reactive ion etching and evaluated as field-effect transistor and chemiresistor gas sensors. The resulting neck-width of the synthesized nanomesh was about ~20 nm comprised of the gap between polystyrene spheres that was formed during the reactive ion etching process. The neck-width and the periodicities of the graphene nanomesh could be easily controlled depending the duration/power of RIE and the size of PS nanospheres. The fabricated GNM transistor device exhibited promising electronic properties featuring high drive current and ION/IOFF ratio of about 6, significantly higher than its film counterpart. Similarly, when applied as chemiresistor gas sensor at room temperature, the graphene nanomesh sensor showed excellent sensitivity towards NO2 and NH3, significantly higher than their film counterparts. The ethanol-based graphene nanomesh sensors exhibited sensitivities of about 4.32%/ppm in NO2 and 0.71%/ppm in NH3 with limit of detections of 15 ppb and 160 ppb, respectively. Our demonstrated studies on controlling the neck width of the nanomesh would lead to further improvement of graphene-based transistors and sensors. PMID:22931286

  6. Greenhouse Gas Emissions of Indianapolis using a High-Density Surface Tower Network and an Atmospheric Inversion

    NASA Astrophysics Data System (ADS)

    Lauvaux, T.; Miles, N. L.; Davis, K. J.; Richardson, S.; Deng, A.; Sarmiento, D. P.; Wu, K.; Sweeney, C.; Karion, A.; Hardesty, R. M.; Brewer, A.; Turnbull, J. C.; Iraci, L. T.; Hillyard, P. W.; Podolske, J. R.; Gurney, K. R.; Patarasuk, R.; Cambaliza, M. O. L.; Shepson, P. B.; Whetstone, J. R.

    2014-12-01

    The Indianapolis Flux Experiment (INFLUX) was designed to develop and evaluate methods of detection and attribution of greenhouse gas fluxes from urban environments. Determination of greenhouse gas fluxes and uncertainty bounds is essential for the evaluation of the effectiveness of mitigation strategies. Indianapolis is intended to serve as a test bed for these methods; the results will inform efforts at measuring emissions from urban centers worldwide, including megacities. The generally accepted method for determining urban greenhouse gas emissions is inventories, which are compiled from records of land use and human activity. Atmospheric methods, in which towers are instrumented with sensors to measure greenhouse gas mole fractions and these data are used in an inversion model, have the potential to provide independent determination of emissions. The current INFLUX observation network includes twelve in-situ tower-based, continuous measurements of CO2. A subset of five towers additionally measure CH4, and a different subset measure CO. The subset measuring CO also include weekly flask samples of a wide variety of trace gases including 14CO2. Here we discuss the observed urban spatial and temporal patterns in greenhouse gas mole fraction in Indianapolis, with the critical result being the detectability of city emissions with this high-density network. We also present the first atmospheric inversion results for both CO2 and CH4, compare these results to inventories, and discuss the effects of critical assumptions in the inversion framework. The construction of unbiased atmospheric modeling systems and well-defined prior errors remains an important step in atmospheric emissions monitoring over urban areas. In order to minimize transport model errors, we developed a WRF-Chem FDDA modeling system ingesting surface and profile measurements of horizontal mean wind, temperature, and moisture. We demonstrate the impact of the meteorological data assimilation system on

  7. Overcoming the high-temperature two-dimensional gas chromatography limits to elute heavy compounds.

    PubMed

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

    2012-03-16

    Overcoming high-temperature (HT) two-dimensional gas chromatography (GC × GC) limits is critical for the analysis of heavy hydrocarbons, particularly those contained in heavy petroleum fractions. To reach this goal, HT-GC × GC analysis was adapted from HT-GC Simulated Distillation (HT-GC SimDist) operating conditions as this analysis embraces compounds whose boiling point ranges from 35 °C to 700 °C and from a previous study that enabled the elution of linear alkane nC(60) and tetraaromatic compounds by HT-GC × GC. This paper shows that HT-GC × GC analysis using CO(2) cryogenic modulator and short wide bore columns with a thin film of stationary phase allows the elution of linear alkanes up to nC(68) (641 °C) as well as of highly aromatic hydrocarbons like coronene. Furthermore, compared to previous studies, an on-column injector was used to reduce discrimination of high boiling point compounds.

  8. Development of high pressure-high vacuum-high conductance piston valve for gas-filled radiation detectors

    NASA Astrophysics Data System (ADS)

    Prasad, D. N.; Ayyappan, R.; Kamble, L. P.; Singh, J. P.; Muralikrishna, L. V.; Alex, M.; Balagi, V.; Mukhopadhyay, P. K.

    2008-05-01

    Gas-filled radiation detectors need gas filling at pressures that range from few cms of mercury to as high as 25kg/cm2 at room temperature. Before gas-filling these detectors require evacuation to a vacuum of the order of ~1 × 10-5 mbar. For these operations of evacuation and gas filling a system consisting of a vacuum pump with a high vacuum gauge, gas cylinder with a pressure gauge and a valve is used. The valve has to meet the three requirements of compatibility with high-pressure and high vacuum and high conductance. A piston valve suitable for the evacuation and gas filling of radiation detectors has been designed and fabricated to meet the above requirements. The stainless steel body (80mm×160mm overall dimensions) valve with a piston arrangement has a 1/2 inch inlet/outlet opening, neoprene/viton O-ring at piston face & diameter for sealing and a knob for opening and closing the valve. The piston movement mechanism is designed to have minimum wear of sealing O-rings. The valve has been hydrostatic pressure tested up to 75bars and has Helium leak rate of less than 9.6×10-9 m bar ltr/sec in vacuum mode and 2×10-7 mbar ltr/sec in pressure mode. As compared to a commercial diaphragm valve, which needed 3 hours to evacuate a 7 litre chamber to 2.5×10-5 mbar, the new valve achieved vacuum 7.4×10-6mbar in the same time under the same conditions.

  9. Fractionation of a galacto-oligosaccharides solution at low and high temperature using nanofiltration

    PubMed Central

    Pruksasri, Suwattana; Nguyen, Thu-Ha; Haltrich, Dietmar; Novalin, Senad

    2015-01-01

    Like in many applications, solutions of high sugar content can cause serious problems due to microorganism contaminations. Hence, the main aim of this work was to study a nanofiltration process for GOS purification at 5 °C and 60 °C that may circumvent or reduce potential microbial growth. Process performances and rejection behaviors of monosaccharide as well as individual GOS components were compared. Operating at 5 °C is more advantageous especially with respect to the oligosaccharide (OS) recovery yield. Using a NF membrane (NP030) at 45 bar, a product purity of 85% (based on monosaccharide content) and an OS recovery yield of 82% could be achieved. However, a low average permeate flux of 3 L/m2 h had to be accepted. A diafiltration step improved product purity to 90% with 30% losses of OS. A qualitative theoretical discussion shows that a possible change of the pore radius distribution depending on temperature could play a role in solute rejection as well as selectivity. PMID:26681914

  10. Gas hydrates (clathrates) causing pore-water freshening and oxygen isotope fractionation in deep-water sedimentary sections of terrigenous continental margins

    USGS Publications Warehouse

    Hesse, R.; Harrison, W.E.

    1981-01-01

    The occurrence of gas hydrates in deep-water sections of the continental margins predicted from anomalous acoustic reflectors on seismic profiles has been confirmed by recent deep-sea drilling results. On the Pacific continental slope off Guatemala gas hydrates were brought up for the first time from two holes (497, 498A) drilled during Leg 67 of the DSDP in water depths of 2360 and 5500 m, respectively. The hydrates occur in organic matter-rich Pleistocene to Miocene terrigenous sediments. In the hydrate-bearing zone a marked decrease in interstitial water chlorinities was observed starting at about 10-20 m subbottom depth. Pore waters at the bottom of the holes (near 400 m subbottom) have as little as half the chlorinity of seawater (i.e. 9???). Similar, but less pronounced, trends were observed during previous legs of the DSDP in other hydrate-prone segments of the continental margins where recharge of fresh water from the continent can be excluded (e.g. Leg 11). The crystallization of hydrates, like ice, excludes salt ions from the crystal structure. During burial the dissolved salts are separated from the solids. Subsidence results in a downward motion of the solids (including hydrates) relative to the pore fluids. Thawing of hydrates during recovery releases fresh water which is remixed with the pore fluid not involved in hydrate formation. The volume of the latter decreases downhole thus causing downward decreasing salinity (chlorinity). Hydrate formation is responsible for oxygen isotope fractionation with 18O-enrichment in the hydrate explaining increasingly more positive ??18O values in the pore fluids recovered (after hydrate dissociation) with depth. ?? 1981.

  11. High temperature heat exchanger studies for applications to gas turbines

    NASA Astrophysics Data System (ADS)

    Min, June Kee; Jeong, Ji Hwan; Ha, Man Yeong; Kim, Kui Soon

    2009-12-01

    Growing demand for environmentally friendly aero gas-turbine engines with lower emissions and improved specific fuel consumption can be met by incorporating heat exchangers into gas turbines. Relevant researches in such areas as the design of a heat exchanger matrix, materials selection, manufacturing technology, and optimization by a variety of researchers have been reviewed in this paper. Based on results reported in previous studies, potential heat exchanger designs for an aero gas turbine recuperator, intercooler, and cooling-air cooler are suggested.

  12. Impact of compression on gas transport in non-woven gas diffusion layers of high temperature polymer electrolyte fuel cells

    NASA Astrophysics Data System (ADS)

    Froning, Dieter; Yu, Junliang; Gaiselmann, Gerd; Reimer, Uwe; Manke, Ingo; Schmidt, Volker; Lehnert, Werner

    2016-06-01

    Gas transport in non-woven gas diffusion layers of a high-temperature polymer electrolyte fuel cell was calculated with the Lattice Boltzmann method. The underlying micro structure was taken from two sources. A real micro structure was analyzed in the synchrotron under the impact of a compression mask mimicking the channel/rib structure of a flow field. Furthermore a stochastic geometry model based on synchrotron X-ray tomography studies was applied. The effect of compression is included in the stochastic model. Gas transport in these micro structures was simulated and the impact of compression was analyzed. Fiber bundles overlaying the micro structure were identified which affect the homogeneity of the gas flow. There are significant deviations between the impact of compression on effective material properties for this type of gas diffusion layers and the Kozeny-Carman equation.

  13. A high-throughput cell-based method to predict the unbound drug fraction in the brain.

    PubMed

    Mateus, André; Matsson, Pär; Artursson, Per

    2014-04-10

    Optimization of drug efficacy in the brain requires understanding of the local exposure to unbound drug at the site of action. This relies on measurements of the unbound drug fraction (fu,brain), which currently requires access to brain tissue. Here, we present a novel methodology using homogenates of cultured cells for rapid estimation of fu,brain. In our setup, drug binding to human embryonic kidney cell (HEK293) homogenate was measured in a small-scale dialysis apparatus. To increase throughput, we combined drugs into cassettes for simultaneous measurement of multiple compounds. Our method estimated fu,brain with an average error of 1.9-fold. We propose that our simple method can be used as an inexpensive, easily available and high-throughput alternative to brain tissues excised from laboratory animals. Thereby, estimates of unbound drug exposure can now be implemented at a much earlier stage of the drug discovery process, when molecular property changes are easier to make.

  14. (30)Si mole fraction of a silicon material highly enriched in (28)Si determined by instrumental neutron activation analysis.

    PubMed

    D'Agostino, Giancarlo; Di Luzio, Marco; Mana, Giovanni; Oddone, Massimo; Pramann, Axel; Prata, Michele

    2015-06-01

    The latest determination of the Avogadro constant, carried out by counting the atoms in a pure silicon crystal highly enriched in (28)Si, reached the target 2 × 10(-8) relative uncertainty required for the redefinition of the kilogram based on the Planck constant. The knowledge of the isotopic composition of the enriched silicon material is central; it is measured by isotope dilution mass spectrometry. In this work, an independent estimate of the (30)Si mole fraction was obtained by applying a relative measurement protocol based on Instrumental Neutron Activation Analysis. The amount of (30)Si isotope was determined by counting the 1266.1 keV γ-photons emitted during the radioactive decay of the radioisotope (31)Si produced via the neutron capture reaction (30)Si(n,γ)(31)Si. The x((30)Si) = 1.043(19) × 10(-6) mol mol(-1) is consistent with the value currently adopted by the International Avogadro Coordination.

  15. The amino acid sequence of protein SCMK-B2C from the high-sulphur fraction of wool keratin.

    PubMed

    Elleman, T C

    1972-08-01

    1. The amino acid sequence of a protein from the reduced and carboxymethylated high-sulphur fraction of wool has been determined. 2. The sequence of this S-carboxymethylkerateine (SCMK-B2C) of 151 amino acid residues displays much internal homology and an unusual residue distribution. Thus a ten-residue sequence occurs four times near the N-terminus and five times near the C-terminus with few changes. These regions contain much of the molecule's half-cystine, whereas between them there is a region of 19 residues that are mainly small and devoid of cystine and proline. 3. Certain models of the wool fibre based on its mechanical and physical properties propose a matrix of small compact globular units linked together to form beaded chains. The unusual distribution of the component residues of protein SCMK-B2C suggests structures in the wool-fibre matrix compatible with certain features of the proposed models.

  16. Significance of High-Speed Air Temperature Measurements in the Sampling Cell of a Closed-Path Gas Analyzer with a Short Tube

    NASA Astrophysics Data System (ADS)

    Kathilankal, James; Fratini, Gerardo; Burba, George

    2015-04-01

    Eddy covariance gas analyzers measure gas content in a known volume, thus essentially measuring gas density. The fundamental flux equation, however, is based on the dry mole fraction. The relationship between dry mole fraction and density is regulated by the ideal gas law describing the processes of temperature- and pressure-related expansions and contractions, and by the law of partial pressures, describing the process of dilution. As a result, this relationship depends on water vapor content, temperature and pressure of the air sample. If the instrument is able to output precise high-speed dry mole fraction, the flux processing is significantly simplified and WPL density terms accounting for the air density fluctuations are no longer required. This should also lead to the reduction in uncertainties associated with the density terms resulting from the eddy covariance measurements of sensible and latent heat fluxes used in these terms. In this framework, three main measurement approaches may be considered: Open-path approach Outputting correct high-speed dry mole fraction from the open-path instrument is difficult because of complexities with maintaining reliable fast temperature measurements integrated over the entire measuring path, and also because of extraordinary challenges with accurate measurements of fast pressure in the open air flow. Classical long-tube closed-path approach For instruments utilizing traditional long-tube closed-path design, with tube length 1000 or more times the tube diameter, the fast dry mole fraction can be used successfully when instantaneous fluctuations in the air temperature of the sampled air are effectively dampened to negligible levels, instantaneous pressure fluctuations are regulated or negligible, and water vapor is measured simultaneously with gas or the air sample is dried. Short-tube closed-path approach, the enclosed design For instruments with a short-tube enclosed design, most - but not all - of the temperature

  17. Studies on the behavior of ammonia and ammonium salts in the atmosphere (1) - Fractional collection of ammonia gas and particulate ammonium

    NASA Technical Reports Server (NTRS)

    Kiin, K.; Fujimura, M.; Hashimoto, Y.

    1981-01-01

    Methods for the fractional collection of trace amounts of atmospheric ammonia gas and ammonium particles on a two staged glass fiber filter are summarized. A standard glass fiber filter washed with distilled water and dried at 120 to 130 C was used. A second filter was impregnated with a mixture of 3% boric acid and 25% glycerin solution. The blank of glass fiber filters impregnated with a mixture of the above solution was very low for ammonia, i.e. 0.06 micrograms in a filter of 47 mm in diameter. The mean concentrations of ammonia and ammonium in air at Kawasaki, a polluted area, were 7.6 and 2.3 micrograms cu m, and those at Sanriku, an unpolluted area 0.9 and 0.2 micrograms cu m, respectively. Ratios of concentration levels of ammonium to total ammonia in the atmosphere were 0.3 and 0.2 for the polluted and unpolluted areas, respectively. Ammonium salts in air at both areas were not correlated with relative humidity. Variations in time of ammonia concentrations and sources in surrounding areas are also considered.

  18. Evaporative fractions and elevation effects on stable isotopes of high elevation lakes and streams in arid western Himalaya

    NASA Astrophysics Data System (ADS)

    Biggs, Trent W.; Lai, Chun-Ta; Chandan, Pankaj; Lee, Raymond Mark; Messina, Alex; Lesher, Rebecca S.; Khatoon, Nisa

    2015-03-01

    Isotopes of oxygen and hydrogen in water from streams, snow, and lakes were used to model the ratio of evaporation to total inflow (E/I) of four high elevation lakes in closed basins in the Indian Himalaya. Air temperature and relative humidity (h) data from meteorological stations and global climate grids (GMAO-MERRA) were used as input to the model. A second model of the volume of inflow during snowmelt constrained the magnitude of seasonal variability in isotopic composition. Similar to other areas of the Himalaya, elevation was a strong determinant of isotopic composition of stream water, suggesting that heavier isotopes rain out at lower elevations. Deuterium excess (d) in stream water suggests that summer precipitation originating from the Bay of Bengal rather than winter precipitation from Central Asia is the dominant source of precipitation. For the largest and deepest lakes (>15 m), E/I was 77-87%, and 18-50% for two shallow lakes (<2 m). Modelled E/I was sensitive to h; ground-level measurements of h are needed to constrain E/I estimates in arid mountain regions, though h from GMAO also produced reasonable E/I values. The results suggest that some lakes in closed basins in the Himalaya lose a significant fraction of their inflow to groundwater, particularly shallow lakes with a low ratio of lake volume to watershed area. Isotopic values from the mainstem of the Indus River suggest that evaporatively enriched waters have limited impact on both wet and dry season discharge at the basin scale. Lakes with a high evaporative fraction may be uniquely sensitive to climate, and isotopic analysis can help identify lakes that may be vulnerable to climate fluctuations and change.

  19. Effect of high- and low-caloric mixed liquid meals on intestinal gas dynamics.

    PubMed

    Harder, Hermann; Hernando-Harder, Ana C; Franke, Andreas; Krammer, Heinz-Juergen; Singer, Manfred V

    2006-01-01

    High-caloric meals can evoke postprandial abdominal complaints involving disturbances in intestinal gas balance. We aimed to determine the influence of the caloric content of meals on intestinal gas dynamics. Eight healthy subjects (five women, three men; age range, 25-43 years) underwent paired studies with low (1 kcal/min)- and high (3 kcal/min)-caloric meal infusion 35% fat, (45% carbohydrate, 20% protein) into the duodenum in random order and proximal jejunal gas infusion. Gas evacuation, perception, and abdominal girth were assessed. The low-caloric meal caused neither gas retention (-7 +/- 58 ml) nor girth changes (0 +/- 0 mm). In contrast, the high-caloric meal led to significant gas retention (705 +/- 56 ml) and increased abdominal perimeter (7 +/- 1 mm; P < 0.001 vs. the low-caloric meal for both). Thus, a high caloric load of nutrients arriving at the duodenum modulates both intestinal gas transit and abdominal perimeter.

  20. Qualitative and quantitative analysis of an alkaloid fraction from Piper longum L. using ultra-high performance liquid chromatography-diode array detector-electrospray ionization mass spectrometry.

    PubMed

    Li, Kuiyong; Fan, Yunpeng; Wang, Hui; Fu, Qing; Jin, Yu; Liang, Xinmiao

    2015-05-10

    In a previous research, an alkaloid fraction and 18 alkaloid compounds were prepared from Piper longum L. by series of purification process. In this paper, a qualitative and quantitative analysis method using ultra-high performance liquid chromatography-diode array detector-mass spectrometry (UHPLC-DAD-MS) was developed to evaluate the alkaloid fraction. Qualitative analysis of the alkaloid fraction was firstly completed by UHPLC-DAD method and 18 amide alkaloid compounds were identified. A further qualitative analysis of the alkaloid fraction was accomplished by UHPLC-MS/MS method. Another 25 amide alkaloids were identified according to their characteristic ions and neutral losses. At last, a quantitative method for the alkaloid fraction was established using four marker compounds including piperine, pipernonatine, guineensine and N-isobutyl-2E,4E-octadecadienamide. After the validation of this method, the contents of above four marker compounds in the alkaloid fraction were 57.5mg/g, 65.6mg/g, 17.7mg/g and 23.9mg/g, respectively. Moreover, the relative response factors of other three compounds to piperine were calculated. A comparative study between external standard quantification and relative response factor quantification proved no remarkable difference. UHPLC-DAD-MS method was demonstrated to be a powerful tool for the characterization of the alkaloid fraction from P. longum L. and the result proved that the quality of alkaloid fraction was efficiently improved after appropriate purification.

  1. Prediction of equilibrium Li isotope fractionation between minerals and aqueous solutions at high P and T: An efficient ab initio approach

    NASA Astrophysics Data System (ADS)

    Kowalski, Piotr M.; Jahn, Sandro

    2011-10-01

    The mass-dependent equilibrium stable isotope fractionation between different materials is an important geochemical process. Here we present an efficient method to compute the isotope fractionation between complex minerals and fluids at high pressure, P, and temperature, T, representative for the Earth's crust and mantle. The method is tested by computation of the equilibrium fractionation of lithium isotopes between aqueous fluids and various Li bearing minerals such as staurolite, spodumene and mica. We are able to correctly predict the direction of the isotope fractionation as observed in the experiments. On the quantitative level the computed fractionation factors agree within 1.0‰ with the experimental values indicating predictive power of ab initio methods. We show that with ab initio methods we are able to investigate the underlying mechanisms driving the equilibrium isotope fractionation process, such as coordination of the fractionating elements, their bond strengths to the neighboring atoms, compression of fluids and thermal expansion of solids. This gives valuable insight into the processes governing the isotope fractionation mechanisms on the atomic scale. The method is applicable to any state and does not require different treatment of crystals and fluids.

  2. Ionic liquid electrolytes with high sodium ion fraction for high-rate and long-life sodium secondary batteries

    NASA Astrophysics Data System (ADS)

    Chen, Chih-Yao; Kiko, Tomohiro; Hosokawa, Takafumi; Matsumoto, Kazuhiko; Nohira, Toshiyuki; Hagiwara, Rika

    2016-11-01

    Sodium secondary batteries are attracting considerably renewed interest as new battery systems owing to the high and uniform abundance and cost advantages of Na. However, their performance is still far from optimal as compared to the well-developed Li-ion technology. Herein, Na secondary batteries with unprecedented rate capability and a long life has been achieved by using a highly concentrated bis(fluorosulfonyl)amide anion (FSA-)-based ionic liquid electrolyte (3.3 mol dm-3 Na[FSA]) and a Na2FeP2O7 positive electrode, in a targeted operating temperature range from room to intermediate. Nearly full discharge capacity is obtained at 4000 mA g-1, and 79% of the capacity is retained at a discharge rate as high as 20000 mA g-1 at 363 K. Stable cycling (>300 cycles) with satisfactory coulombic efficiency (>99.5%) is found at an intermediate rate (100 mA g-1) over 298-363 K. A high-rate cycling test (1000 mA g-1) at 363 K reveals that the cell could retain 93% of its initial capacity after 1500 cycles.

  3. Characterization of bovine kappa-casein fractions and the kinetics of chymosin-induced macropeptide release from carbohydrate-free and carbohydrate-containing fractions determined by high-performance gel-permeation chromatography.

    PubMed Central

    Vreeman, H J; Visser, S; Slangen, C J; Van Riel, J A

    1986-01-01

    Bovine kappa-casein was fractionated at pH 8.0 on DEAE-Sepharose with an NaCl gradient, followed by DEAE-cellulose chromatography using a decreasing pH gradient from pH 6.0 to 4.5. At least ten components could be identified, each differing in N-acetylneuraminic acid (NeuAc) and/or phosphorus content. Two components appeared to be multiply-phosphorylated, but did not contain NeuAc. The possible significance of this finding in relation to the mode of phosphorylation and glycosylation in vivo is discussed. A carbohydrate-free fraction as well as two NeuAc-containing fractions were compared in their substrate behaviour towards the action of the milk-clotting enzyme chymosin at pH 6.6 and 30 degrees C. To this end the trichloroacetic acid-soluble reaction products were analysed by high-performance gel-permeation chromatography. In order of increasing carbohydrate content the kcat. values found ranged from 40 to 25 s-1 and the Km values from 9 to 3 microM; the overall substrate properties of these components as reflected by the kinetic parameter kcat./Km ranged from 5 to 8 microM-1 X S-1. Irreversible polymerization of the carbohydrate-free fraction brought about a more-than-2-fold increase in Km, the kcat. value remaining virtually constant. The kcat./Km found for the cleavage of whole kappa-casein at pH 6.6 was of the same magnitude as the kcat./Km found for the polymerized carbohydrate-free fraction (i.e. about 3 microM-1 X S-1). No indication of substrate inhibition was found for the carbohydrate-free fraction. Images Fig. 1. Fig. 2. Fig. 4. PMID:3103611

  4. Anaerobic digestion of organic fraction of municipal solid waste combining two pretreatment modalities, high temperature microwave and hydrogen peroxide

    SciTech Connect

    Shahriari, Haleh; Warith, Mostafa; Hamoda, Mohamed; Kennedy, Kevin J.

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer Microwave and H{sub 2}O{sub 2} pretreatment were studied to enhance anaerobic digestion of organic waste. Black-Right-Pointing-Pointer The whole waste pretreated at 115 Degree-Sign C or 145 Degree-Sign C had the highest biogas production. Black-Right-Pointing-Pointer Biogas production of the whole waste decreased at 175 Degree-Sign C due to formation of refractory compounds. Black-Right-Pointing-Pointer Pretreatment to 145 Degree-Sign C and 175 Degree-Sign C were the best when considering only the free liquid fraction. Black-Right-Pointing-Pointer H{sub 2}O{sub 2} pretreatment had a lag phase and the biogas production was not higher than MW pretreated samples. - Abstract: In order to enhance anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW), pretreatment combining two modalities, microwave (MW) heating in presence or absence of hydrogen peroxide (H{sub 2}O{sub 2}) were investigated. The main pretreatment variables affecting the characteristics of the OFMSW were temperature (T) via MW irradiation and supplemental water additions of 20% and 30% (SWA20 and SW30). Subsequently, the focus of this study was to evaluate mesophilic batch AD performance in terms of biogas production, as well as changes in the characteristics of the OFMSW post digestion. A high MW induced temperature range (115-175 Degree-Sign C) was applied, using sealed vessels and a bench scale MW unit equipped with temperature and pressure controls. Biochemical methane potential (BMP) tests were conducted on the whole OFMSW as well as the liquid fractions. The whole OFMSW pretreated at 115 Degree-Sign C and 145 Degree-Sign C showed 4-7% improvement in biogas production over untreated OFMSW (control). When pretreated at 175 Degree-Sign C, biogas production decreased due to formation of refractory compounds, inhibiting the digestion. For the liquid fraction of OFMSW, the effect of pretreatment on the cumulative biogas production (CBP

  5. Low inlet gas velocity high throughput biomass gasifier

    DOEpatents

    Feldmann, Herman F.; Paisley, Mark A.

    1989-01-01

    The present invention discloses a novel method of operating a gasifier for production of fuel gas from carbonaceous fuels. The process disclosed enables operating in an entrained mode using inlet gas velocities of less than 7 feet per second, feedstock throughputs exceeding 4000 lbs/ft.sup.2 -hr, and pressures below 100 psia.

  6. The ATLAS3D project - XX. Mass-size and mass-σ distributions of early-type galaxies: bulge fraction drives kinematics, mass-to-light ratio, molecular gas fraction and stellar initial mass function

    NASA Astrophysics Data System (ADS)

    Cappellari, Michele; McDermid, Richard M.; Alatalo, Katherine; Blitz, Leo; Bois, Maxime; Bournaud, Frédéric; Bureau, M.; Crocker, Alison F.; Davies, Roger L.; Davis, Timothy A.; de Zeeuw, P. T.; Duc, Pierre-Alain; Emsellem, Eric; Khochfar, Sadegh; Krajnović, Davor; Kuntschner, Harald; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Scott, Nicholas; Serra, Paolo; Weijmans, Anne-Marie; Young, Lisa M.

    2013-07-01

    ) and dwarf irregulars (Im), respectively. We use dynamical models to analyse our kinematic maps. We show that σe traces the bulge fraction, which appears to be the main driver for the observed trends in the dynamical (M/L)JAM and in indicators of the (M/L)pop of the stellar population like Hβ and colour, as well as in the molecular gas fraction. A similar variation along contours of σe is also observed for the mass normalization of the stellar initial mass function (IMF), which was recently shown to vary systematically within the ETGs' population. Our preferred relation has the form log _{10} [(M/L)_stars/(M/L)_Salp]=a+b× log _{10}({σ _e}/130 {km s^{-1}}) with a = -0.12 ± 0.01 and b = 0.35 ± 0.06. Unless there are major flaws in all stellar population models, this trend implies a transition of the mean IMF from Kroupa to Salpeter in the interval log _{10}({σ _e}/{km s}^{-1})≈ 1.9-2.5 (or {σ _e}≈ 90-290 km s-1), with a smooth variation in between, consistently with what was shown in Cappellari et al. The observed distribution of galaxy properties on the MP provides a clean and novel view for a number of previously reported trends, which constitute special two-dimensional projections of the more general four-dimensional parameters trends on the MP. We interpret it as due to a combination of two main effects: (i) an increase of the bulge fraction, which increases σe, decreases Re, and greatly enhance the likelihood for a galaxy to have its star formation quenched, and (ii) dry merging, increasing galaxy mass and Re by moving galaxies along lines of roughly constant σe (or steeper), while leaving the population nearly unchanged.

  7. Studies of long chain lipids in insects by high temperature gas chromatography and high temperature gas chromatography-mass spectrometry.

    PubMed

    Sutton, Paul A; Wilde, Michael J; Martin, Stephen J; Cvačka, Josef; Vrkoslav, Vladimír; Rowland, Steven J

    2013-07-01

    The organic compounds occurring naturally on the cuticles (surfaces) of insects are important for insect communication, help to act as protective water barriers and are useful in chemical taxonomy. Typically the cuticular lipids are only studied by gas chromatography-mass spectrometry (GC-MS) of hexane or pentane extracts, so the normal limitations of GC-MS makes it perhaps unsurprising that compounds with more than about 35 carbon atoms have only rarely been reported. Here we show by high temperature (HT) GC and HTGC-MS of extracts of eleven species of insects from nine genera, that longer chain compounds are actually common. Wax esters and triacylglycerides are virtually ubiquitous in such extracts, but long chain (>C35) hydrocarbons also sometimes occur. Whilst the latter have occasionally been reported previously from mass spectrometry studies, the use of the HTGC combination with MS allowed even some isobaric isomers to be separated and thus more complete lipid distributions to be monitored. Since the physical properties of cuticular compounds depend on this composition of the mixtures, such differences may influence the water loss rates of the insects, amongst other effects. In addition, the high molecular weight compound profiles may allow species to be more easily differentiated, one from another. It would be interesting to apply these methods to examination of the cuticular lipids of insects on a more routine basis, ideally in combination with MALDI-TOF-MS and imaging methods. PMID:23726079

  8. A High Efficiency PSOFC/ATS-Gas Turbine Power System

    SciTech Connect

    W.L. Lundberg; G.A. Israelson; M.D. Moeckel; S.E. Veyo; R.A. Holmes; P.R. Zafred; J.E. King; R.E. Kothmann

    2001-02-01

    A study is described in which the conceptual design of a hybrid power system integrating a pressurized Siemens Westinghouse solid oxide fuel cell generator and the Mercury{trademark} 50 gas turbine was developed. The Mercury{trademark} 50 was designed by Solar Turbines as part of the US. Department of Energy Advanced Turbine Systems program. The focus of the study was to develop the hybrid power system concept that principally would exhibit an attractively-low cost of electricity (COE). The inherently-high efficiency of the hybrid cycle contributes directly to achieving this objective, and by employing the efficient, power-intensive Mercury{trademark} 50, with its relatively-low installed cost, the higher-cost SOFC generator can be optimally sized such that the minimum-COE objective is achieved. The system cycle is described, major system components are specified, the system installed cost and COE are estimated, and the physical arrangement of the major system components is discussed. Estimates of system power output, efficiency, and emissions at the system design point are also presented. In addition, two bottoming cycle options are described, and estimates of their effects on overall-system performance, cost, and COE are provided.

  9. Multiphysics methods development for high temperature gas reactor analysis

    NASA Astrophysics Data System (ADS)

    Seker, Volkan

    Multiphysics computational methods were developed to perform design and safety analysis of the next generation Pebble Bed High Temperature Gas Cooled Reactors. A suite of code modules was developed to solve the coupled thermal-hydraulics and neutronics field equations. The thermal-hydraulics module is based on the three dimensional solution of the mass, momentum and energy equations in cylindrical coordinates within the framework of the porous media method. The neutronics module is a part of the PARCS (Purdue Advanced Reactor Core Simulator) code and provides a fine mesh finite difference solution of the neutron diffusion equation in three dimensional cylindrical coordinates. Coupling of the two modules was performed by mapping the solution variables from one module to the other. Mapping is performed automatically in the code system by the use of a common material mesh in both modules. The standalone validation of the thermal-hydraulics module was performed with several cases of the SANA experiment and the standalone thermal-hydraulics exercise of the PBMR-400 benchmark problem. The standalone neutronics module was validated by performing the relevant exercises of the PBMR-268 and PBMR-400 benchmark problems. Additionally, the validation of the coupled code system was performed by analyzing several steady state and transient cases of the OECD/NEA PBMR-400 benchmark problem.

  10. Ztek`s ultra high efficiency fuel cell/gas turbine combination

    SciTech Connect

    Hsu, M.; Nathanson, D.

    1995-10-19

    Ztek is proceeding on development of an ultra-high efficiency hybrid system of its Planar SOFC with a gas turbine, realizing shared cost and performance benefits. The gas turbine as the Balance-of-Plant was a logical selection from a fuel cell system perspective because of (1) the high-power-density energy conversion of gas turbines; (2) the unique compatibility of the Ztek Planar SOFC with gas turbines, and (3) the availability of low-cost commercial gas turbine systems. A Tennessee Valley Authority/Ztek program is ongoing, which addresses operation of the advanced Planar SOFC stacks and design scale-up for utility power generation applications.

  11. High-temperature gas-cooled reactors: preliminary safety and environmental information document. Volume IV

    SciTech Connect

    Not Available

    1980-01-01

    Information is presented concerning medium-enriched uranium/thorium once-through fuel cycle; medium-enrichment uranium-233/thorium recycle fuel; high-enrichment uranium-235/thorium recycle (spiked) fuel cycle; high-enrichment uranium-233/thorium recycle (spiked) fuel cycle; and gas-turbine high-temperature gas-cooled reactor.

  12. Fractionated stereotactic radiotherapy plus bevacizumab after response to bevacizumab plus irinotecan as a rescue treatment for high-grade gliomas

    PubMed Central

    Conde-Moreno, Antonio José; García-Gómez, Raquel; Albert-Antequera, María; Almendros-Blanco, Piedad; De Las Peñas-Bataller, Ramón; González-Vidal, Verónica; López-Torrecilla, José Luis; Ferrer-Albiach, Carlos

    2015-01-01

    Aim To evaluate the possibility of implementing a new scheme of rescue treatment after relapse or progression of high-grade glioma (HGG) treated at the first-line with bevacizumab and irinotecan (BVZ+CPT11), evaluating the response and toxicity of associating BVZ and fractionated stereotactic radiotherapy (BVZ+FSRT). Materials and methods We retrospectively analysed data from 59 patients with relapse of HGG. Nine patients with HGG relapse after treatment using the Stupp protocol that were treated with BVZ+CPT11 for progression between July 2007 and August 2012, after which the response was assessed according to the Revised Assessment in Neuro-Oncology (RANO) criteria. BVZ was administered at a dose of 10 mg/kg and FSRT up to a prescribed dose of 30 Gy, 500 cGy per fraction, three days a week. The median follow-up was 38 months. Results The treatment was well-tolerated by all patients. The response after nuclear magnetic resonance imaging (MRI) at 3–6 months was progression in two patients, stable disease in four, and three patients had a partial response. The median overall survival (OS) from diagnosis until death or the last control was 36.8 months. The median progression-free survival (PFS) was 10.8 months. The results from tumour sub-group analysis indicated that the PFS was not statistically significant although it seemed that it was higher in grade-III. The OS was higher in grade-III gliomas. Conclusions The combination of BVZ+FSRT as a second-line HGG relapse rescue treatment is well-tolerated and seems to offer promising results. We believe that multi-centre prospective studies are needed to determine the long-term efficacy and toxicity of this therapeutic approach. PMID:25949228

  13. Improvements in dose calculation accuracy for small off-axis targets in high dose per fraction tomotherapy

    SciTech Connect

    Hardcastle, Nicholas; Bayliss, Adam; Wong, Jeannie Hsiu Ding; Rosenfeld, Anatoly B.; Tome, Wolfgang A.

    2012-08-15

    Purpose: A recent field safety notice from TomoTherapy detailed the underdosing of small, off-axis targets when receiving high doses per fraction. This is due to angular undersampling in the dose calculation gantry angles. This study evaluates a correction method to reduce the underdosing, to be implemented in the current version (v4.1) of the TomoTherapy treatment planning software. Methods: The correction method, termed 'Super Sampling' involved the tripling of the number of gantry angles from which the dose is calculated during optimization and dose calculation. Radiochromic film was used to measure the dose to small targets at various off-axis distances receiving a minimum of 21 Gy in one fraction. Measurements were also performed for single small targets at the center of the Lucy phantom, using radiochromic film and the dose magnifying glass (DMG). Results: Without super sampling, the peak dose deficit increased from 0% to 18% for a 10 mm target and 0% to 30% for a 5 mm target as off-axis target distances increased from 0 to 16.5 cm. When super sampling was turned on, the dose deficit trend was removed and all peak doses were within 5% of the planned dose. For measurements in the Lucy phantom at 9.7 cm off-axis, the positional and dose magnitude accuracy using super sampling was verified using radiochromic film and the DMG. Conclusions: A correction method implemented in the TomoTherapy treatment planning system which triples the angular sampling of the gantry angles used during optimization and dose calculation removes the underdosing for targets as small as 5 mm diameter, up to 16.5 cm off-axis receiving up to 21 Gy.

  14. KECK SPECTROSCOPY OF FAINT 3>z>7 LYMAN BREAK GALAXIES: A HIGH FRACTION OF LINE EMITTERS AT REDSHIFT SIX

    SciTech Connect

    Stark, Daniel P.; Ellis, Richard S.; Ouchi, Masami

    2011-02-10

    As Ly{alpha} photons are scattered by neutral hydrogen, a change with redshift in the Ly{alpha} equivalent width (EW) distribution of distant galaxies offers a promising probe of the degree of ionization in the intergalactic medium and hence when cosmic reionization ended. This simple test is complicated by the fact that Ly{alpha} emission can also be affected by variations in the kinematics and dust content of the host galaxies. In the first paper in this series, we demonstrated both a luminosity- and redshift-dependent trend in the fraction of Ly{alpha} emitters seen within color-selected 'Lyman break' galaxies (LBGs) over the range 3 < z < 6; lower luminosity galaxies and those at higher redshift show an increased likelihood of strong emission. Here, we present the results from 12.5 hr exposures with the Keck DEIMOS spectrograph focused primarily on LBGs at z {approx_equal} 6 which enable us to confirm the redshift dependence of line emission more robustly and to higher redshift than was hitherto possible. We find that 54% {+-} 11% of faint z {approx_equal} 6 LBGs show strong (W{sub Ly{alpha},0}>25 A) emission, an increase of 55% from a sample of similarly luminous z {approx_equal} 4 galaxies. With a total sample of 74 z {approx_equal} 6 LBGs, we determine the luminosity-dependent Ly{alpha} EW distribution. Assuming continuity in these trends to the new population of z {approx_equal} 7 sources located with the Hubble WFC3/IR camera, we predict that unless the neutral fraction rises in the intervening 200 Myr, the success rate for spectroscopic confirmation using Ly{alpha} emission should be high.

  15. Direct measurement of the plasma loss width in an optimized, high ionization fraction, magnetic multi-dipole ring cusp

    NASA Astrophysics Data System (ADS)

    Cooper, C. M.; Weisberg, D. B.; Khalzov, I.; Milhone, J.; Flanagan, K.; Peterson, E.; Wahl, C.; Forest, C. B.

    2016-10-01

    The loss width of plasma in the WiPAL multi-dipole magnetic ring cusp [Cooper et al., Phys. Plasmas 21, 13505 (2014); Forest et al., J. Plasma Phys. 81, 345810501 (2015)] has been directly measured using a novel array of probes embedded in the insulating plasma limiters. The large plasma volume ( ˜10 m3), small loss area associated with strong rare earth permanent magnets ( Bo˜2.23 kG at face), and large heating power ( ≤200 kW) produces a broad range of electron temperatures ( 2 fractions ( 0.05 high magnetic fields, differs from previous devices: the cusp loss width is much larger than the Debye length and electron gyroradius and comparable to the collision length. Plasma parameters measured at the surface of ceramic limiter tiles covering the magnets and along radial chords in the cusp magnetic field indicate that electron density and temperature are nearly constant on magnetic field lines and that the mirror forces play little role in confining the plasma other than to constrict the loss area. Particle balance modeling is used to determine the cross field diffusion coefficient base on the measured losses to the limiters. The experimentally determined cross field diffusion coefficient (which determines the cusp loss width) is consistent with ambipolar diffusion across five orders of magnitude. The ambipolar diffusion across a given field line is set primarily by the electron-neutral collisions in the region where the magnetic field is the weakest, even though these plasmas can have ionization fractions near 1.

  16. High-Temperature Magnetic Bearings for Gas Turbine Engines

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Magnetic bearings are the subject of a new NASA Lewis Research Center and U.S. Army thrust with significant industry participation, and coordination with other Government agencies. The NASA/Army emphasis is on high-temperature applications for future gas turbine engines. Magnetic bearings could increase the reliability and reduce the weight of these engines by eliminating the lubrication system. They could also increase the DN (diameter of the bearing times rpm) limit on engine speed and allow active vibration cancellation systems to be used--resulting in a more efficient, "more electric" engine. Finally, the Integrated High-Performance Turbine Engine Technology (IHPTET) Program, a joint Department of Defense/industry program, identified a need for a hightemperature (as high as 1200 F) magnetic bearing that could be demonstrated in a phase III engine. This magnetic bearing is similar to an electric motor. It has a laminated rotor and stator made of cobalt steel. Wound around the stator are a series of electrical wire coils that form a series of electric magnets around the circumference. The magnets exert a force on the rotor. A probe senses the position of the rotor, and a feedback controller keeps it in the center of the cavity. The engine rotor, bearings, and case form a flexible structure that contains a large number of modes. The bearing feedback controller, which could cause some of these modes to become unstable, could be adapted to varying flight conditions to minimize seal clearances and monitor the health of the system. Cobalt steel has a curie point greater than 1700 F, and copper wire has a melting point beyond that. Therefore, practical limitations associated with the maximum magnetic field strength in the cobalt steel and the stress in the rotating components limit the temperature to about 1200 F. The objective of this effort is to determine the limits in temperature and speed of a magnetic bearing operating in an engine. Our approach is to use our in

  17. Two-dimensional electron gas (2DEG) mobility affected by the in mole fraction fluctuation in InxAl1-xN/GaN heterostructures

    NASA Astrophysics Data System (ADS)

    Liu, Guipeng; Zhang, Jinfeng; Lu, Kunyi; Chen, Wenjie; Tian, Yonghui; Yang, Jianhong

    2016-09-01

    In an InxAl1-xN/GaN heterostructure, we have studied the mobility limited by the In mole fraction fluctuation scattering. The In mole fraction fluctuation characterizes the quality of the InxAl1-xN material with two parameters, one is the mole fraction fluctuation δx and the other is its lateral s Λ. Similar to a roughness scattering, for a fixed mole fraction x, the mobility limited by the In mole fraction fluctuation initially decreases with Λ increasing, reaches a minimum at a certain value of Λ and then increases.

  18. Analysis of human plasma lipids by using comprehensive two-dimensional gas chromatography with dual detection and with the support of high-resolution time-of-flight mass spectrometry for structural elucidation.

    PubMed

    Salivo, Simona; Beccaria, Marco; Sullini, Giuseppe; Tranchida, Peter Q; Dugo, Paola; Mondello, Luigi

    2015-01-01

    The main focus of the present research is the analysis of the unsaponifiable lipid fraction of human plasma by using data derived from comprehensive two-dimensional gas chromatography with dual quadrupole mass spectrometry and flame ionization detection. This approach enabled us to attain both mass spectral information and analyte percentage data. Furthermore, gas chromatography coupled with high-resolution time-of-flight mass spectrometry was used to increase the reliability of identification of several unsaponifiable lipid constituents. The synergism between both the high-resolution gas chromatography and mass spectrometry processes enabled us to attain a more in-depth knowledge of the unsaponifiable fraction of human plasma. Additionally, information was attained on the fatty acid and triacylglycerol composition of the plasma samples, subjected to investigation by using comprehensive two-dimensional gas chromatography with dual quadrupole mass spectrometry and flame ionization detection and high-performance liquid chromatography with atmospheric pressure chemical ionization quadrupole mass spectrometry, respectively.

  19. An Introduction to Continued Fractions.

    ERIC Educational Resources Information Center

    Moore, Charles G.

    Provided is an introduction to the properties of continued fractions for the intellectually curious high school student. Among the topics included are (1) Expansion of Rational Numbers into Simple Continued Fractions, (2) Convergents, (3) Continued Fractions and Linear Diophantine Equations of the Type am + bn = c, (4) Continued Fractions and…

  20. The difficulty of getting high escape fractions of ionizing photons from high-redshift galaxies: a view from the FIRE cosmological simulations

    NASA Astrophysics Data System (ADS)

    Ma, Xiangcheng; Kasen, Daniel; Hopkins, Philip F.; Faucher-Giguère, Claude-André; Quataert, Eliot; Kereš, Dušan; Murray, Norman

    2015-10-01

    We present a series of high-resolution (20-2000 M⊙, 0.1-4 pc) cosmological zoom-in simulations at z ≳ 6 from the Feedback In Realistic Environment (FIRE) project. These simulations cover halo masses 109-1011 M⊙ and rest-frame ultraviolet magnitude MUV = -9 to -19. These simulations include explicit models of the multi-phase ISM, star formation, and stellar feedback, which produce reasonable galaxy properties at z = 0-6. We post-process the snapshots with a radiative transfer code to evaluate the escape fraction (fesc) of hydrogen ionizing photons. We find that the instantaneous fesc has large time variability (0.01-20 per cent), while the time-averaged fesc over long time-scales generally remains ≲ 5 per cent, considerably lower than the estimate in many reionization models. We find no strong dependence of fesc on galaxy mass or redshift. In our simulations, the intrinsic ionizing photon budgets are dominated by stellar populations younger than 3 Myr, which tend to be buried in dense birth clouds. The escaping photons mostly come from populations between 3 and 10 Myr, whose birth clouds have been largely cleared by stellar feedback. However, these populations only contribute a small fraction of intrin