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Sample records for exchange high performance

  1. Technology Performance Exchange

    SciTech Connect

    2015-09-01

    To address the need for accessible, high-quality data, the Department of Energy has developed the Technology Performance Exchange (TPEx). TPEx enables technology suppliers, third-party testing laboratories, and other entities to share product performance data. These data are automatically transformed into a format that technology evaluators can easily use in their energy modeling assessments to inform procurement decisions.

  2. Separation of nucleic acids by high-performance ion-exchange chromatography.

    PubMed

    Yamazaki, K; Tomizawa, H; Miyanaga, A; Ishikawa, O; Nakatani, S; Moriyama, H

    1995-01-01

    Separation of various nucleic acids was evaluated by high-performance ion-exchange chromatography on non-porous resin, TSKgel DNA-NPR. A 1 kb ladder DNA was studied as a model DNA on operational variables like flow rate, gradient time, temperature, sample load, etc.. As results, various DNA fragments were well separated within 15 min by 20 min linear gradient at a flow rate between 0.5 and 0.75 ml/min at room temperature while the resolutin was dependent on molecular weight of the sample. The relationship between sample load and its peak area was examined on polymerase chain reaction (PCR) product. The product was found to be quantitatively recovered even with nanogram loads. The detection limit was 3.8 ng at signal to noise level (S/N) of 3. This non-porous ion-exchanger also showed high resolution on separation of ther nucleic acids like transfer RNA, oligonucleotides (single-stranded) DNA. PMID:8841596

  3. Improvement in high temperature proton exchange membrane fuel cells cathode performance with ammonium carbonate

    NASA Astrophysics Data System (ADS)

    Song, Ying; Wei, Yu; Xu, Hui; Williams, Minkmas; Liu, Yuxiu; Bonville, Leonard J.; Russell Kunz, H.; Fenton, James M.

    Proton exchange membrane (PEM) fuel cells with optimized cathode structures can provide high performance at higher temperature (120 °C). A "pore-forming" material, ammonium carbonate, applied in the unsupported Pt cathode catalyst layer of a high temperature membrane electrode assembly enhanced the catalyst activity and minimized the mass-transport limitations. The ammonium carbonate amount and Nafion ® loading in the cathode were optimized for performance at two conditions: 80 °C cell temperature with 100% anode/75% cathode R.H. and 120 °C cell temperature with 35% anode/35% cathode R.H., both under ambient pressure. A cell with 20 wt.% ammonium carbonate and 20 wt.% Nafion ® operating at 80 °C and 120 °C presented the maximum cell performance. Hydrogen/air cell voltages at a current density of 400 mA cm -2 using the Ionomem/UConn membrane as the electrolyte with a cathode platinum loading of 0.5 mg cm -2 were 0.70 V and 0.57 V at the two conditions, respectively. This was a 19% cell voltage increase over a cathode without the "pore-forming" ammonium carbonate at the 120 °C operating condition.

  4. High Performance Non-Dispersive X-Ray Spectrometers for Charge Exchange Measurements

    NASA Technical Reports Server (NTRS)

    Porter Frederick; Adams, J.; Beiersdorfer, P.; Brown, G. V.; Karkatoua, D.; Kelley, R. L.; Kilbourne, C. A.; Lautenagger, M.

    2010-01-01

    Currently, the only measurements of cosmological charge exchange have been made using low resolution, non-dispersive spectrometers like the PSPC on ROSAT and the CCD instruments on Chandra and XMM/Newton. However, upcoming cryogenic spectrometers on Astro-H and IXO will add vast new capabilities to investigate charge exchange in local objects such as comets and planetary atmospheres. They may also allow us to observe charge exchange in extra-solar objects such as galactic supernova remnants. With low spectral resolution instruments such as CCDs, x-ray emission due to charge exchange recombination really only provides information on the acceptor species, such as the solar wind. With the new breed of x-ray calorimeter instruments, emission from charge exchange becomes highly diagnostic allowing one to uniquely determine the acceptor species, ionization state, donor species and ionization state, and the relative velocity of the interaction. We will describe x-ray calorimeter instrumentation and its potential for charge exchange measurements in the near term. We will also touch on the instrumentation behind a decade of high resolution measurements of charge exchange using an x-ray calorimeter at the Lawrence Livermore National Laboratory.

  5. Performance of selected anion exchange resins for the treatment of a high DOC content surface water.

    PubMed

    Humbert, Hugues; Gallard, Hervé; Suty, Hervé; Croué, Jean-Philippe

    2005-05-01

    The objective of this study was first to compare the performance of four strong anion exchange resins (AERs) (MIEX from Orica Pty Ltd, DOWEX-11 and DOWEX-MSA from DOW chemical and IRA-938 from Rohm and Haas) for their application in drinking water treatment (natural organic matter (NOM), mineral anions (nitrate, sulfate and bromide) and pesticide removal) using bench-scale experimental procedures on a high DOC content surface water. The efficiency of MIEX for NOM and mineral anions removal was furthermore evaluated using bench-scale dose-response experiments on raw, clarified and post-ozonated waters. NOM removal was assessed using the measurement of dissolved organic carbon (DOC), UV absorbance at 254 nm (UV254) and the use of high-performance size exclusion chromatography with UV (HPSEC/UV) and fluorescence detection (HPSEC/FLUO). The MIEX and IRA938 anionic resins exhibit a faster removal of NOM and mineral anions compared to the DOWEX11 and MSA AERs. All the resins were found to be very effective with similar performances after 30 to 45 min of contact time. As expected, only limited sorption of atrazine and isoproturon (C0=1 microg/L) occurred with MIEX, DOWEX11 and MSA AERs. MIEX resin proved to be very efficient in eliminating NOM of high-molecular weight but also a large part of the smallest UV absorbing organic compounds which were refractory to coagulation/flocculation treatment. Remaining DOC levels after 30 min of contact with MIEX were found similar in raw water, clarified water and even post-ozonated water implying no DOC benefit can be gained by employing conventional treatment prior to MIEX treatment. Removal of bromide (initial concentration 110 microg/L) was also observed and ranged from 30% to 65% for resin dose increasing from 2 to 8 mL/L. T PMID:15899268

  6. Tunable high performance cross-linked alkaline anion exchange membranes for fuel cell applications.

    PubMed

    Robertson, Nicholas J; Kostalik, Henry A; Clark, Timothy J; Mutolo, Paul F; Abruña, Héctor D; Coates, Geoffrey W

    2010-03-17

    Fuel cells are energy conversion devices that show great potential in numerous applications ranging from automobiles to portable electronics. However, further development of fuel cell components is necessary for them to become commercially viable. One component critical to their performance is the polymer electrolyte membrane, which is an ion conductive medium separating the two electrodes. While proton conducting membranes are well established (e.g., Nafion), hydroxide conducting membranes (alkaline anion exchange membranes, AAEMs) have been relatively unexplored by comparison. Operating under alkaline conditions offers significant efficiency benefits, especially for the oxygen reduction reaction; therefore, effective AAEMs could significantly advance fuel cell technologies. Here we demonstrate the use of ring-opening metathesis polymerization to generate new cross-linked membrane materials exhibiting high hydroxide ion conductivity and good mechanical properties. Cross-linking allows for increased ion incorporation, which, in turn supports high conductivities. This facile synthetic approach enables the preparation of cross-linked materials with the potential to meet the demands of hydrogen-powered fuel cells as well as direct methanol fuel cells. PMID:20178312

  7. Tunable High Performance Cross-Linked Alkaline Anion Exchange Membranes for Fuel Cell Applications

    SciTech Connect

    Robertson, Nicholas J.; Kostalik, IV, Henry A.; Clark, Timothy J.; Mutolo, Paul F.; Abruña, Héctor D.; Coates, Geoffrey W.

    2010-02-23

    Fuel cells are energy conversion devices that show great potential in numerous applications ranging from automobiles to portable electronics. However, further development of fuel cell components is necessary for them to become commercially viable. One component critical to their performance is the polymer electrolyte membrane, which is an ion conductive medium separating the two electrodes. While proton conducting membranes are well established (e.g., Nafion), hydroxide conducting membranes (alkaline anion exchange membranes, AAEMs) have been relatively unexplored by comparison. Operating under alkaline conditions offers significant efficiency benefits, especially for the oxygen reduction reaction; therefore, effective AAEMs could significantly advance fuel cell technologies. Here we demonstrate the use of ring-opening metathesis polymerization to generate new cross-linked membrane materials exhibiting high hydroxide ion conductivity and good mechanical properties. Cross-linking allows for increased ion incorporation, which, in turn supports high conductivities. This facile synthetic approach enables the preparation of cross-linked materials with the potential to meet the demands of hydrogen-powered fuel cells as well as direct methanol fuel cells.

  8. Analysis of Amadori compounds by high-performance cation exchange chromatography coupled to tandem mass spectrometry.

    PubMed

    Davidek, Tomas; Kraehenbuehl, Karin; Devaud, Stéphanie; Robert, Fabien; Blank, Imre

    2005-01-01

    High-performance cation exchange chromatography coupled to tandem mass spectrometry or electrochemical detection was found to be an efficient tool for analyzing Amadori compounds derived from hexose and pentose sugars. The method allows rapid separation and identification of Amadori compounds, while benefiting from the well-known advantages of mass spectrometry, such as specificity and sensitivity. Glucose- and xylose-derived Amadori compounds of several amino acids, such as glycine, alanine, valine, leucine/isoleucine, methionine, proline, phenylalanine, and glutamic acid, were separated or discriminated using this new method. The method is suitable for the analysis of both model reaction mixtures and food products. Fructosylglutamate was found to be the major Amadori compound in dried tomatoes (approximately 1.5 g/100 g) and fructosylproline in dried apricots (approximately 0.2 g/100 g). Reaction of xylose and glycine at 90 degrees C (pH 6) for 2 h showed rapid formation of xylulosylglycine (approximately 12 mol %, 15 min) followed by slow decrease over time. Analysis of pentose-derived Amadori compounds is shown for the first time, which represents a major breakthrough in studying occurrence, formation, and decomposition of these labile Maillard intermediates. PMID:15623289

  9. High Temperature Heat Exchanger Project

    SciTech Connect

    Anthony E. Hechanova, Ph.D.

    2008-09-30

    The UNLV Research Foundation assembled a research consortium for high temperature heat exchanger design and materials compatibility and performance comprised of university and private industry partners under the auspices of the US DOE-NE Nuclear Hydrogen Initiative in October 2003. The objectives of the consortium were to conduct investigations of candidate materials for high temperature heat exchanger componets in hydrogen production processes and design and perform prototypical testing of heat exchangers. The initial research of the consortium focused on the intermediate heat exchanger (located between the nuclear reactor and hydrogen production plan) and the components for the hydrogen iodine decomposition process and sulfuric acid decomposition process. These heat exchanger components were deemed the most challenging from a materials performance and compatibility perspective

  10. Technology Performance Exchange (Fact Sheet)

    SciTech Connect

    Not Available

    2012-10-01

    This fact sheet, 'The Technology Performance Exchange' will be presented at the ET Summit, held at the Pasadena Convention Center on October 15-17, 2012. The Technology Performance Exchange will be a centralized, Web-based portal for finding and sharing energy performance data for commercial building technologies.

  11. Manipulating Water in High-Performance Hydroxide Exchange Membrane Fuel Cells through Asymmetric Humidification and Wetproofing

    SciTech Connect

    Kaspar, RB; Letterio, MP; Wittkopf, JA; Gong, K; Gu, S; Yan, YS

    2015-02-18

    Hydroxide exchange membrane fuel cells (HEMFCs) are an emerging low-cost alternative to conventional proton exchange membrane fuel cells. In addition to producing water at the anode, HEMFCs consume water at the cathode, leading to distinctive water transport behavior. We report that gas diffusion layer (GDL) wetproofing strictly lowers cell performance, but that the penalty is much higher when the anode side is wetproofed compared to the cathode side. We attribute this penalty primarily to mass transport losses from anode flooding, suggesting that cathode humidification may be more beneficial than anode humidification for this device. GDLs with little or no wetproofing perform best, yielding a competitive peak power density of 737 mW cm(-2). (C) The Author(s) 2015. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, hup://creativecommons.orgilicenses/by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited. All rights reserved.

  12. Demonstration and Performance Monitoring of Foundation Heat Exchangers (FHX) in Ultra-High Energy Efficient Research Homes

    SciTech Connect

    Im, Piljae; Hughes, Patrick; Liu, Xiaobing

    2012-01-01

    The more widespread use of Ground Source Heat Pump (GSHP) systems has been hindered by their high first cost, which is mainly driven by the cost of the drilling and excavation for installation of ground heat exchangers (GHXs). A new foundation heat exchanger (FHX) technology was proposed to reduce first cost by placing the heat exchanger into the excavations made during the course of construction (e.g., the overcut for the basement and/or foundation and run-outs for water supply and the septic field). Since they reduce or eliminate the need for additional drilling or excavation, foundation heat exchangers have the potential to significantly reduce or eliminate the first cost premium associated with GSHPs. Since December 2009, this FHX technology has been demonstrated in two ultra-high energy efficient new research houses in the Tennessee Valley, and the performance data has been closely monitored as well. This paper introduces the FHX technology with the design, construction and demonstration of the FHX and presents performance monitoring results of the FHX after one year of monitoring. The performance monitoring includes hourly maximum and minimum entering water temperature (EWT) in the FHX compared with the typical design range, temperature difference (i.e., T) across the FHX, and hourly heat transfer rate to/from the surrounding soil.

  13. Wheat gluten amino acid analysis by high-performance anion-exchange chromatography with integrated pulsed amperometric detection.

    PubMed

    Rombouts, Ine; Lagrain, Bert; Lamberts, Lieve; Celus, Inge; Brijs, Kristof; Delcour, Jan A

    2012-01-01

    This chapter describes an accurate and user-friendly method for determining amino acid composition of wheat gluten proteins and their gliadin and glutenin fractions. The method consists of hydrolysis of the peptide bonds in 6.0 M hydrochloric acid solution at 110°C for 24 h, followed by evaporation of the acid and separation of the free amino acids by high-performance anion-exchange chromatography with integrated pulsed amperometric detection. In contrast to conventional methods, the analysis requires neither pre- or postcolumn derivatization, nor a time-consuming oxidation or derivatization step prior to hydrolysis. Correction factors account for incomplete release of Val and Ile even after hydrolysis for 24 h, and for losses of Ser during evaporation. Gradient conditions including an extra eluent allow multiple sequential sample analyses without risk of Glu accumulation on the anion-exchange column which otherwise would result from high Gln levels in gluten proteins. PMID:22125156

  14. Heat exchanger performance monitoring guidelines

    SciTech Connect

    Stambaugh, N. ); Closser, W. Jr. ); Mollerus, F.J. )

    1991-12-01

    Fouling can occur in many heat exchanger applications in a way that impedes heat transfer and fluid flow and reduces the heat transfer or performance capability of the heat exchanger. Fouling may be significant for heat exchanger surfaces and flow paths in contact with plant service water. This report presents guidelines for performance monitoring of heat exchangers subject to fouling. Guidelines include selection of heat exchangers to monitor based on system function, safety function and system configuration. Five monitoring methods are discussed: the heat transfer, temperature monitoring, temperature effectiveness, delta P and periodic maintenance methods. Guidelines are included for selecting the appropriate monitoring methods and for implementing the selected methods. The report also includes a bibliography, example calculations, and technical notes applicable to the heat transfer method.

  15. Fractals for multicyclic synthesis conditions of biopolymers. Examples of oligonucleotide synthesis measured by high-performance capillary electrophoresis and ion-exchange high-performance liquid chromatography.

    PubMed

    Földes-Papp, Z; Birch-Hirschfeld, E; Eickhoff, H; Baumann, G; Peng, W G; Biber, T; Seydel, R; Kleinschmidt, A K; Seliger, H

    1996-07-19

    We have developed models of patterns for nucleotide chain growth. These patterns are measurable by high-performance capillary electrophoresis and ion-exchange high-performance liquid chromatography in crude products of solid-phase synthesized 30mer and 65mer oligodeoxyribonucleotide target sequences N. We introduce mathematical methods for finding characteristic values d(o) and p(o) for constant chemical modes of growth as well as d and p for non-constant chemical modes of growth (d = probability of propagation, p = probability of termination). These methods are employed by presenting the accompanying computer software developed by us in C code, Mathematica R languages, and Fortran. Characteristic values of the parameters d, p, and the target nucleotide length N describe the complete composition of the crude product. From this we have developed the relation 2 - [N/(N - 1)]/Da, measurable(N,d) as a universal quantitative measure for multicyclic synthesis conditions (D, fractal dimension and similarity exponent, respectively). We use this mathematical treatment to compare the efficiency of oligodeoxyribonucleotide syntheses of different target length N on polymer support materials. Further, we analyze selected syntheses of short and long oligodeoxyribonucleotides as well as single-stranded DNA sequences by well-known empirical autocorrelation, fast Fourier transformation, and embedding dimension techniques. PMID:8765856

  16. Protein losses in ion-exchange and hydrophobic interaction high-performance liquid chromatography

    SciTech Connect

    Goheen, Steven C.; Gibbins, Betty M.

    2000-01-01

    Protein losses in ion-exchange and hydrophobic interaction HPLC were examined. The supports were allnon-porous, packed in columns of identical dimensions. Two ion-exchange chromatography (IEC), anion and cation, as well as a hydrophobic interaction chromatography (HIC) columns were tested. Proteins included cytochrome c, bovine serum albumin (BSA), immunoglobulin G and fibrinogen. Temperature effects on HIC supports were studied for cytochrome c and BSA. Both retention times and recoveries of the proteins were measured. The influence of column residence time on the recovery of proteins were also investigated. We found a linear relationship between the amount of protein recovered and the log of the molecular mass. Retention times also generally increased with temperature for both HIC and IEC. Other trends in retention behavior and recoveries are discussed.

  17. Thermal hydraulic performance testing of printed circuit heat exchangers in a high-temperature helium test facility

    SciTech Connect

    Sai K. Mylavarapu; Xiaodong Sun; Richard E. Glosup; Richard N. Christensen; Michael W. Patterson

    2014-04-01

    In high-temperature gas-cooled reactors, such as a very high temperature reactor (VHTR), an intermediate heat exchanger (IHX) is required to efficiently transfer the core thermal output to a secondary fluid for electricity generation with an indirect power cycle and/or process heat applications. Currently, there is no proven high-temperature (750–800 °C or higher) compact heat exchanger technology for high-temperature reactor design concepts. In this study, printed circuit heat exchanger (PCHE), a potential IHX concept for high-temperature applications, has been investigated for their heat transfer and pressure drop characteristics under high operating temperatures and pressures. Two PCHEs, each having 10 hot and 10 cold plates with 12 channels (semicircular cross-section) in each plate are fabricated using Alloy 617 plates and tested for their performance in a high-temperature helium test facility (HTHF). The PCHE inlet temperature and pressure were varied from 85 to 390 °C/1.0–2.7 MPa for the cold side and 208–790 °C/1.0–2.7 MPa for the hot side, respectively, while the mass flow rate of helium was varied from 15 to 49 kg/h. This range of mass flow rates corresponds to PCHE channel Reynolds numbers of 950 to 4100 for the cold side and 900 to 3900 for the hot side (corresponding to the laminar and laminar-to-turbulent transition flow regimes). The obtained experimental data have been analyzed for the pressure drop and heat transfer characteristics of the heat transfer surface of the PCHEs and compared with the available models and correlations in the literature. In addition, a numerical treatment of hydrodynamically developing and hydrodynamically fully-developed laminar flow through a semicircular duct is presented. Relations developed for determining the hydrodynamic entrance length in a semicircular duct and the friction factor (or pressure drop) in the hydrodynamic entry length region for laminar flow through a semicircular duct are given. Various

  18. [Determination of succinic acid in desvenlafaxine succinate by high performance ion-exclusion chromatography and high performance ion-exchange chromatography].

    PubMed

    Zong, Yanping; Li, Jinghua; Sun, Wei; Liu, Guixia; Lu, Jinghua; Shan, Guangzhi

    2016-02-01

    New methods were developed for the determination of succinic acid in desvenlafaxine succinate (DVS) by high performance ion-exclusion chromatography (HPIEC) and high performance ion-exchange chromatography (HPIC). HPIEC and HPIC methods were used separately to determinate the succinic acid in DVS. With HPIEC, the sample was diluted with 2. 50 x 10(-3) mol/L sulfuric acid solution and filtrated by 0. 22 µm polyether sulfone filter membrane, and then analyzed by HPIEC directly without any further pretreatment. The analytical column was Phenomenex Rezex ROA-organic Acid H+(8%) (300 mmx7. 8 mm). The mobile phase was 2. 50x10(-3) mol/L sulfuric acid solution at the flow rate of 0. 5 mL/min. The column temperature was set at 40 °C, and the detection wavelength was 210 nm. The injection volume was 10 KL. The assay was quantified by external standard method. With HPIC, the sample was diluted with ultrapure water and filtrated by 0. 22 µm polyether sulfone filter membrane, and then analyzed by HPIC directly without any further pretreatment. The analytical column was Dionex IonPac AS11-HC (250 mm x 4 mm) with a guard column IonPacAG11-HC (50 mm x 4 mm). Isocratic KOH elute generator was used at the flow rate of 1. 0 mL/min. The detection was performed by a Dionex suppressed (DIONEX AERS 500 4-mm) conductivity detector. The injection volume was 10 µL. The content computation was performed with peak area external reference method. The results of HPIEC method for succinic acid were 28. 8%, 28. 9% and 28. 9%, while the results of HPIEC method were 28. 2%, 28. 6% and 28. 6%. The results of HPIEC and HPIC methods were not significantly different. The two methods can both be used to determine the contents of succinic acid in DVS. The surveillance analytical method should be chosen according to the situation. PMID:27382725

  19. Wheat gluten amino acid composition analysis by high-performance anion-exchange chromatography with integrated pulsed amperometric detection.

    PubMed

    Rombouts, Ine; Lamberts, Lieve; Celus, Inge; Lagrain, Bert; Brijs, Kristof; Delcour, Jan A

    2009-07-17

    A simple accurate method for determining amino acid composition of wheat gluten proteins and their gliadin and glutenin fractions using high-performance anion-exchange chromatography with integrated pulsed amperometric detection is described. In contrast to most conventional methods, the analysis requires neither pre- or post-column derivatization, nor oxidation of the sample. It consists of hydrolysis (6.0M hydrochloric acid solution at 110 degrees C for 24h), evaporation of hydrolyzates (110 degrees C), and chromatographic separation of the liberated amino acids. Correction factors (f) accounted for incomplete cleavage of peptide bonds involving Val (f=1.07) and Ile (f=1.13) after hydrolysis for 24h and for Ser (f=1.32) losses during evaporation. Gradient conditions including an extra eluent (0.1M acetic acid solution) allowed multiple sequential sample analyses without risk of Glu contamination on the anion-exchange column. While gluten amino acid compositions by the present method were mostly comparable to those obtained by a conventional method involving oxidation, acid hydrolysis and post-column ninhydrin derivatization, the latter method underestimated Tyr, Val and Ile levels. Results for the other amino acids obtained by the different methods were linearly correlated (r>0.99, slope=1.03). PMID:19523641

  20. High performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD) for the sensitive determination of hyaluronan oligosaccharides.

    PubMed

    Rothenhöfer, Martin; Grundmann, Marco; Bernhardt, Günther; Matysik, Frank-Michael; Buschauer, Armin

    2015-04-15

    High performance anion exchange chromatography (HPAEC) with pulsed amperometric detection (PAD) was optimized for the analysis of oligosaccharides derived from the extracellular matrix component hyaluronan. Using this sensitive approach, the separation of oligosaccharides consisting of two (molecular weight ca. 0.8 kDa) up to 25-30 (molecular weight: ca. 9.5-11.4 kDa) disaccharide moieties was possible. Standard oligosaccharides (comprising 2-4 repetitive disaccharides) were detectable at very low amounts of 0.2-0.3 pmol (20-30 nM). Including 10 min of column equilibration, a complex mixture of low molecular weight hyaluronan can be analyzed within 40 min. The HPAEC method was successfully applied to the study of the size-dependency of both the action of bovine testicular hyaluronidase (BTH) and the precipitation of hyaluronan by cetyltrimethylammonium bromide (CTAB), a physicochemical reaction often used for the determination of hyaluronan and hyaluronidase activity. PMID:25768984

  1. Technical Exchange on Improved Design and Performance of High Level Waste Melters - Final Report

    SciTech Connect

    SK Sundaram; ML Elliott; D Bickford

    1999-11-19

    SIA Radon is responsible for management of low- and intermediate-level radioactive waste (LILW) produced in Central Russia. In cooperation with Minatom organizations Radon carries out R and D programs on treatment of simulated high level waste (HLW) as well. Radon scientists deal with a study of materials for LILW, HLW, and Nuclear Power Plants (NPP) wastes immobilization, and development and testing of processes and technologies for waste treatment and disposal. Radon is mostly experienced in LILW vitrification. This experience can be carried over to HLW vitrification especially in field of melting systems. The melter chosen as a basic unit for the vitrification plant is a cold crucible. Later on Radon experience in LILW vitrification as well as our results on simulated HLW vitrification are briefly described.

  2. Quantification of melamine in human urine using cation-exchange based high performance liquid chromatography tandem mass spectrometry.

    PubMed

    Panuwet, Parinya; Nguyen, Johnny V; Wade, Erin L; D'Souza, Priya E; Ryan, P Barry; Barr, Dana Boyd

    2012-03-01

    Melamine and cyanuric acid have been implicated as adulterants in baby formula in China and pet foods in North America. In China, the effect of melamine or melamine-cyanuric acid adulteration lead to kidney stone development and acute renal failure in thousands of Chinese infants. A selective and sensitive analytical method was developed to measure melamine in human urine in order to evaluate the extent of potential health implications resulting from the consumption of these types of adulterated products in the general US population. This method involves extracting melamine from human urine using cation-exchange solid-phase extraction, chromatographically separating it from its urinary matrix co-extractants on a silica-based, strong-cation exchange analytical column using high performance liquid chromatography, and analysis using positive mode electrospray ionization tandem mass spectrometry. Quantification was performed using modified, matrix-based isotope dilution calibration covering the concentration range of 0.50-100 ng/mL. The limit of detection, calculated using replicates of blank and low level spiked samples, was 0.66 ng/mL and the relative standard deviations were between 6.89 and 14.9%. The relative recovery of melamine was 101-106%. This method was tested for viability by analyzing samples collected from the general US population. Melamine was detected in 76% of the samples tested, with a geometric mean of 2.37 ng/mL, indicating that this method is suitable for reliably detecting background exposures to melamine or other chemicals from which it can be derived. PMID:22309774

  3. The Priority and Challenge of High-Power Performance of Low-Platinum Proton-Exchange Membrane Fuel Cells.

    PubMed

    Kongkanand, Anusorn; Mathias, Mark F

    2016-04-01

    Substantial progress has been made in reducing proton-exchange membrane fuel cell (PEMFC) cathode platinum loadings from 0.4-0.8 mgPt/cm(2) to about 0.1 mgPt/cm(2). However, at this level of cathode Pt loading, large performance loss is observed at high-current density (>1 A/cm(2)), preventing a reduction in the overall stack cost. This next developmental step is being limited by the presence of a resistance term exhibited at these lower Pt loadings and apparently due to a phenomenon at or near the catalyst surface. This issue can be addressed through the design of catalysts with high and stable Pt dispersion as well as through development and implementation of ionomers designed to interact with Pt in a way that does not constrain oxygen reduction reaction rates. Extrapolating from progress made in past decades, we are optimistic that the concerted efforts of materials and electrode designers can resolve this issue, thus enabling a large step toward fuel cell vehicles that are affordable for the mass market. PMID:26961326

  4. Characterization of At- species in simple and biological media by high performance anion exchange chromatography coupled to gamma detector.

    PubMed

    Sabatié-Gogova, A; Champion, J; Huclier, S; Michel, N; Pottier, F; Galland, N; Asfari, Z; Chérel, M; Montavon, G

    2012-04-01

    Astatine is a rare radioelement belonging to the halogen group. Considering the trace amounts of astatine produced in cyclotrons, its chemistry cannot be evaluated by spectroscopic tools. Analytical tools, provided that they are coupled with a radioactive detection system, may be an alternative way to study its chemistry. In this research work, high performance anion exchange chromatography (HPAEC) coupled to a gamma detector (γ) was used to evaluate astatine species under reducing conditions. Also, to strengthen the reliability of the experiments, a quantitative analysis using a reactive transport model has been done. The results confirm the existence of one species bearing one negative charge in the pH range 2-7.5. With respect to the other halogens, its behavior indicates the existence of negative ion, astatide At(-). The methodology was successfully applied to the speciation of the astatine in human serum. Under fixed experimental conditions (pH 7.4-7.5 and redox potential of 250 mV) astatine exists mainly as astatide At(-) and does not interact with the major serum components. Also, the method might be useful for the in vitro stability assessment of (211)At-labeled molecules potentially applicable in nuclear medicine. PMID:22405318

  5. Assay for inorganic pyrophosphate in chondrocyte culture using anion-exchange high-performance liquid chromatography and radioactive orthophosphate labeling

    SciTech Connect

    Prins, A.P.; Kiljan, E.; v.d. Stadt, R.J.; v.d. Korst, J.K.

    1986-02-01

    A method is described for determination of inorganic pyrophosphate (PPi) in cell culture medium and in rabbit articular chondrocytes grown in the presence of radioactive orthophosphate (/sup 32/Pi). Intra- and extracellular /sup 32/PPi formed was measured using high-performance liquid chromatographic (HPLC) separation of the PPi from orthophosphate (Pi) and other phosphate-containing compounds. The chromatographic separation on a weak anion-exchange column is based on the extent to which various phosphate compounds form complexes with Mg2+ at low pH and the rate at which such formation occurs. These complexes are eluted more readily than the uncomplexed compounds. Best results were obtained using a simultaneous gradient of Mg2+ ions and ionic strength. In this case separation of small amounts of PPi from a large excess of Pi was possible without prior removal of Pi or extraction of the PPi fraction. The assay is also useful for measurement of inorganic pyrophosphatase activity. The sensitivity of the assay depends on the specific activity of the added /sup 32/Pi and on the culture conditions, but is comparable with the most sensitive of the enzymatic assays. Sample preparation, particularly deproteinization, proved to be of importance. The losses of PPi which occur during procedures of this sort due to hydrolysis and coprecipitation were quantitated.

  6. [Determination of fructooligosaccharides in milk powder using high performance anion-exchange chromatography coupled with pulsed amperometric detection].

    PubMed

    Geng, Lijuan; Huang, Junrong; Feng, Feng; Jiang, Pingping; Chu, Xiaogang; Zhang, Feng; Ling, Yun

    2014-12-01

    Fructooligosaccharides (FOS) are usually added in milk powder as a kind of prebiotic. Thus, quantitative analysis of the FOS is very important for the quality control of milk powder. In this study, a simple method for the simultaneous determination of three FOS components with degrees of polymerization (DP) 3-5 in milk powder was developed by high performance anion-exchange chromatography coupled with pulsed amperometric detection (HPAEC-PAD). The samples were extracted with 50% (v/v) ethanol aqueous solution and defatted by an On Guard RP pretreatment column. The separation was performed on a CarboPac PA200 column by gradient elution using deionized water, 0. 2 mol/L NaOH solution and 0. 4 mol/L NaAc solution as the mobile phases. The flow rate was 0. 4 mL/min. The column temperature was 30 °C; and the injection volume was 25 µL. Good linear response was observed in the concentration range of 0.05-10 mg/L (r2 >0. 9993). The limits of quantification were 0. 02, 0. 005 and 0. 02 mg/L for 1-kestose, nystose and fructofuranosyl-nystose, respectively. The mean recoveries varied from 86. 0% to 114. 0% at three spiked levels of 0. 5, 1. 0 and 5. 0 mg/L. The short-chain fructooligosaccharides from inulooligosaccharides (IOS) were successfully separated by the developed HPAEC-PAD method. The method is simple, accurate, sensitive, and helpful for the quality control of milk powder. PMID:25902647

  7. Development of a High-Performance Fin-and-Tube Heat Exchanger with Vortex Generators for a Vending Machine

    NASA Astrophysics Data System (ADS)

    Iwasaki, Masamichi; Saito, Hiroshi; Mochizuki, Sadanari; Murata, Akira

    The effect of delta-wing-vortex generators (combination of a delta wing and a delta winglet pair) on the heat transfer performance of fin-and-tube heat exchangers for vending machines has been investegated. Flow visualizations, numerical simulations and heat transfer experiments were conducted to find an optimum geometrical shape and arrangement of the vortex generators. Maximum heat transfer enhancement was achieved by the combination of (a) the delta wing with the apex angle of 86 degrees and (b) the delta winglet pair with the inline angle of 45 degrees. In relatively low Reynolds number range, about 40 % increase in heat transfer coefficient was attained with the above mentioned combination of the vortex generators compared to the ordinary heat exchangers with plain fins. It was revealed that the heat transfer enhancement was attributed to (1) the longitudinal vortexes generated by the delta wing and (2) the reduction of wake area behind the tube. It was also found that an increase in the apex angle of the delta wing brought about heat transfer enhancement, and the scale as well as the streggth of the induced longitudinal vortices played an important role in the heat transfer performance.

  8. High heat flux single phase heat exchanger

    NASA Technical Reports Server (NTRS)

    Valenzuela, Javier A.; Izenson, Michael G.

    1990-01-01

    This paper presents the results obtained to date in a program to develop a high heat flux, single-phase heat exchanger for spacecraft thermal management. The intended application is a net generation interface heat exchanger to couple the crew module water thermal bus to the two-phase ammonia main thermal bus in the Space Station Freedom. The large size of the interface heat exchanger is dictated by the relatively poor water-side heat transfer characteristics. The objective of this program is to develop a single-phase heat transfer approach which can achieve heat fluxes and heat transfer coefficients comparable to those of the evaporation ammonia side. A new heat exchanger concept has been developed to meet these objecties. The main feature of this heat exchanger is that it can achieve very high heat fluxes with a pressure drop one to two orders of magnitude lower than those of previous microchannel or jet impingement high heat flux heat exchangers. This paper describes proof-of-concept experiments performed in air and water and presents analytical model of the heat exchanger.

  9. Pion exchange at high energies

    SciTech Connect

    Jones, L.M.

    1980-07-01

    The state of Regge pion exchange calculations for high-energy reactions is reviewed. Experimental evidence is summarized to show that (i) the pion trajectory has a slope similar to that of other trajectories; (ii) the pion exchange contribution can dominate contributions of higher trajectories up to quite a large energy; (iii) many two-body cross sections with large pion contributions can be fit only by models which allow for kinematical conspiracy at t=0. The theory of kinematic conspiracy is reviewed for two-body amplitudes, and calculations of the conspiring pion--Pomeron cut discussed. The author then summarizes recent work on pion exchange in Reggeized Deck models for multiparticle final states, with emphasis on the predictions of various models (with and without resonances) for phases of the partial wave amplitudes.

  10. Heat exchanger performance monitoring guidelines. Final report

    SciTech Connect

    Stambaugh, N.; Closser, W. Jr.; Mollerus, F.J.

    1991-12-01

    Fouling can occur in many heat exchanger applications in a way that impedes heat transfer and fluid flow and reduces the heat transfer or performance capability of the heat exchanger. Fouling may be significant for heat exchanger surfaces and flow paths in contact with plant service water. This report presents guidelines for performance monitoring of heat exchangers subject to fouling. Guidelines include selection of heat exchangers to monitor based on system function, safety function and system configuration. Five monitoring methods are discussed: the heat transfer, temperature monitoring, temperature effectiveness, delta P and periodic maintenance methods. Guidelines are included for selecting the appropriate monitoring methods and for implementing the selected methods. The report also includes a bibliography, example calculations, and technical notes applicable to the heat transfer method.

  11. Enhanced performance and stability of high temperature proton exchange membrane fuel cell by incorporating zirconium hydrogen phosphate in catalyst layer

    NASA Astrophysics Data System (ADS)

    Barron, Olivia; Su, Huaneng; Linkov, Vladimir; Pollet, Bruno G.; Pasupathi, Sivakumar

    2015-03-01

    Zirconium hydrogen phosphate (ZHP) together with polytetrafluoroethylene (PTFE) polymer binder is incorporated into the catalyst layers (CLs) of ABPBI (poly(2,5-benzimidazole))-based high temperature polymer electrolyte membrane fuel cell (HT-PEMFCs) to improve its performance and durability. The influence of ZHP content (normalised with respect to dry PTFE) on the CL properties are structurally characterised by scanning electron microscopy (SEM) and mercury intrusion porosimetry. Electrochemical analyses of the resultant membrane electrode assemblies (MEAs) are performed by recording polarisation curves and impedance spectra at 160 °C, ambient pressure and humidity. The result show that a 30 wt.% ZHP/PTFE content in the CL is optimum for improving fuel cell performance, the resultant MEA delivers a peak power of 592 mW cm-2 at a cell voltage of 380 mV. Electrochemical impedance spectra (EIS) indicate that 30% ZHP in the CL can increase the proton conductivity compared to the pristine PTFE-gas diffusion electrode (GDE). A short term stability test (∼500 h) on the 30 wt.% ZHP/PTFE-GDE shows a remarkable high durability with a degradation rate as low as ∼19 μV h-1 at 0.2 A cm-2, while 195 μV h-1 was obtained for the pristine GDE.

  12. Highly tritiated water processing by isotopic exchange

    SciTech Connect

    Shu, W.M.; Willms, R.S.; Glugla, M.; Cristescu, I.; Michling, R.; Demange, D.

    2015-03-15

    Highly tritiated water (HTW) is produced in fusion machines and one of the promising technologies to process it is isotopic exchange. 3 kinds of Pt-catalyzed zeolite (13X-APG, CBV-100-CY and HiSiv-1000) were tested as candidates for isotopic exchange of highly tritiated water (HTW), and CBV-100-CY (Na-Y type with a SiO{sub 2}/Al{sub 2}O{sub 3} ratio of ∼ 5.0) shows the best performance. Small-scale tritium testing indicates that this method is efficient for reaching an exchange factor (EF) of 100. Full-scale non-tritium testing implies that an EF of 300 can be achieved in 24 hours of operation if a temperature gradient is applied along the column. For the isotopic exchange, deuterium recycled from the Isotope Separation System (deuterium with 1% T and/or 200 ppm T) should be employed, and the tritiated water regenerated from the Pt-catalyzed zeolite bed after isotopic exchange should be transferred to Water Detritiation System (WDS) for further processing.

  13. Determination of sucralose in Splenda and a sugar-free beverage using high-performance anion-exchange chromatography with pulsed amperometric detection.

    PubMed

    Hanko, Valoran P; Rohrer, Jeffrey S

    2004-07-14

    Sucralose is a chlorinated carbohydrate nonnutritive sweetener of food and beverage products. The determination of sucralose in food and beverages is important to ensure consistency in product quality. Sucralose was determined in two commercial products without sample preparation using high-performance anion-exchange (HPAE) chromatography coupled with pulsed amperometric detection (PAD). Sucralose was determined with a 10 min isocratic separation. To determine sucralose and other carbohydrates (e.g., dextrose) simultaneously, a gradient separation was developed. The linear range of electrochemical response extended over 3 orders of magnitude, from 0.01 (LOD) to 40 microM (16 microg/mL; 25 microL injection). High precision, high spike recovery, and method ruggedness were observed for both samples. PMID:15237939

  14. Performance degradation studies on an poly 2,5-benzimidazole high-temperature proton exchange membrane fuel cell using an accelerated degradation technique

    NASA Astrophysics Data System (ADS)

    Jung, Guo-Bin; Chen, Hsin-Hung; Yan, Wei-Mon

    2014-02-01

    In this work, the performance degradation of a poly 2,5-benzimidazole (ABPBI) based high-temperature proton exchange membrane fuel cell (HT-PEMFC) was examined using an accelerated degradation technique (ADT). Experiments using an ADT with 30 min intervals were performed by applying 1.5 V to a membrane electrode assembly (MEA) with hydrogen and nitrogen feeding to the anode and cathode, respectively, to simulate the high voltage generated during fuel cell shutdown and restart. The characterization of the MEAs was performed using in-situ and ex-situ electrochemical methods, such as polarization curves, AC impedance, and cyclic voltammetry (CV), and TEM imaging before and after the ADT experiments. The measured results demonstrated that the ADT testing could be used to dramatically reduce the duration of the degradation. The current output at 0.4 V decreased by 48% after performing ADT testing for 30 min. From the AC impedance, CV and RTGA measurements, the decline in cell performance was found to be primarily due to corrosion and thinning of the catalyst layer (or carbon support) during the first 30 min, leading to the dissolution and agglomeration of the platinum catalyst.

  15. Size exclusion and anion exchange high performance liquid chromatography for characterizing metals bound to marine dissolved organic matter.

    PubMed

    García-Otero, Natalia; Bermejo-Barrera, Pilar; Moreda-Piñeiro, Antonio

    2013-01-14

    Size exclusion chromatography (SEC) followed by anion exchange chromatography (AEC) hyphenated with inductively coupled plasma-mass spectrometry (ICP-MS) was applied for fractionating metals bound to marine dissolved organic matter (DOM). Surface seawater samples (100 L) were subjected to tangential flow ultrafiltration (10,000 Da cut off) for isolating and pre-concentrating dissolved large molecules. The isolated fraction (retentate) consisted of 1L, which was further freeze-dried and re-dissolved to 250 mL with ultrapure water. After HI Trap desalting of the re-dissolved retentate, SEC with UV detection showed marine DOM ranging from 6.5 kDa (lower than the permeable volume of the SEC column) to 16 kDa. A further characterization of this fraction by AEC with UV detection revealed the existence of four groups of macromolecules exhibiting retention times of 2.3, 2.8, 4.5 and 14.0 min. AEC hyphenated with ICP-MS showed the presence of strontium and zinc in the first AE fraction isolated from the SEC fraction; while manganese was found to be bound to the second AE fraction. Cobalt was found to be bound to molecules comprising the third AE fraction. PMID:23265737

  16. Carbon supported Ag nanoparticles as high performance cathode catalyst for H2/O2 anion exchange membrane fuel cell

    PubMed Central

    Xin, Le; Zhang, Zhiyong; Wang, Zhichao; Qi, Ji; Li, Wenzhen

    2013-01-01

    A solution phase-based nanocapsule method was successfully developed to synthesize non-platinum metal catalyst—carbon supported Ag nanoparticles (Ag/C). XRD patterns and TEM image show Ag nanoparticles with a small average size (5.4 nm) and narrow size distribution (2–9 nm) are uniformly dispersed on the carbon black Vulcan XC-72 support. The intrinsic activity and pathway of oxygen reduction reaction (ORR) on the Ag/C and commercial Pt/C were investigated using rotating ring disk electrode (RRDE) tests at room temperature. The results confirmed that the 4-electron pathway of ORR proceeds on small Ag nanoparticles, and showed comparable ORR activities on the self-prepared Ag/C and a commercial Pt/C. A single H2-O2 anion exchange membrane fuel cell (AEMFC) with the Ag/C cathode catalyst exhibited an open circuit potential of 0.98 V and a peak power density of 190 mW/cm2 at 80°C. PMID:24790944

  17. Synthesis of Capsule-like Porous Hollow Nanonickel Cobalt Sulfides via Cation Exchange Based on the Kirkendall Effect for High-Performance Supercapacitors.

    PubMed

    Tang, Yongfu; Chen, Shunji; Mu, Shichun; Chen, Teng; Qiao, Yuqing; Yu, Shengxue; Gao, Faming

    2016-04-20

    To construct a suitable three-dimensional structure for ionic transport on the surface of the active materials for a supercapacitor, porous hollow nickel cobalt sulfides are successfully synthesized via a facile and efficient cation-exchange reaction in a hydrothermal process involving the Kirkendall effect with γ-MnS nanorods as a sacrificial template. The formation mechanism of the hollow nickel cobalt sulfides is carefully illustrated via the tuning reaction time and reaction temperature during the cation-exchange process. Due to the ingenious porous hollow structure that offers a high surface area for electrochemical reaction and suitable paths for ionic transport, porous hollow nickel cobalt sulfide electrodes exhibit high electrochemical performance. The Ni1.77Co1.23S4 electrode delivers a high specific capacity of 224.5 mAh g(-1) at a current density of 0.25 A g(-1) and a high capacity retention of 87.0% at 10 A g(-1). An all-solid-state asymmetric supercapacitor, assembled with a Ni1.77Co1.23S4 electrode as the positive electrode and a homemade activated carbon electrode as the negative electrode (denoted as NCS//HMC), exhibits a high energy density of 42.7 Wh kg(-1) at a power density of 190.8 W kg(-1) and even 29.4 Wh kg(-1) at 3.6 kW kg(-1). The fully charged as-prepared asymmetric supercapacitor can light up a light emitting diode (LED) indicator for more than 1 h, indicating promising practical applications of the hollow nickel cobalt sulfides and the NCS//HMC asymmetric supercapacitor. PMID:27031254

  18. Determination of antisense phosphorothioate oligonucleotides and catabolites in biological fluids and tissue extracts using anion-exchange high-performance liquid chromatography and capillary gel electrophoresis.

    PubMed

    Chen, S H; Qian, M; Brennan, J M; Gallo, J M

    1997-04-25

    Chemically modified phosphorothioate oligodeoxynucleotides (ODNs) have become critical tools for research in the fields of gene expression and experimental therapeutics. Bioanalytical assays were developed that utilized fast anion-exchange high-performance liquid chromatography (HPLC) and capillary gel electrophoresis (CGE) for the determination of 20-mer ODNs in biological fluids (plasma and urine) and tissues. A 20 mer ODN in the antisense orientation directed against DNA methyltransferase (denoted as MT-AS) was studied as the model ODN. The anion-exchange HPLC method employed a short column packed with non-porous polymer support and a ternary gradient elution with 2 M lithium bromide containing 30% formamide. Analysis of the MT-AS is accomplished within 5 min with a detection limit of approximately 3 ng on-column at 267 nm. For plasma and urine, samples were diluted with Nonidet P-40 in 0.9% NaCl and directly injected onto the column, resulting in 100% recovery. For tissue homogenates, a protein kinase K digestion and phenol-chloroform extraction were used, with an average recovery of about 50%. Since the HPLC assay cannot provide one-base separation, biological samples were also processed by an anion-exchange solid-phase extraction and a CGE method to characterize MT-AS and its catabolites of 15-20-mer, species most relevant to biological activity. One base separation, under an electric field of 400 V/cm at room temperature, was achieved for a mixture of 15-20-mer with about 50 pg injected. Assay validation studies revealed that the combined HPLC-CGE methods are accurate, reproducible and specific for the determination of MT-AS and its catabolites in biological fluids and tissue homogenates, and can be used for the pharmacokinetic characterization of MT-AS. PMID:9187382

  19. Simultaneous determination of two Amadori compounds in Korean red ginseng (Panax ginseng) extracts and rat plasma by high-performance anion-exchange chromatography with pulsed amperometric detection.

    PubMed

    Joo, Kyung-Mi; Park, Chan-Woong; Jeong, Hye-Jin; Lee, Sang Jun; Chang, Ih Seop

    2008-04-01

    A new simple, rapid and sensitive high-performance anion-exchange chromatography method with pulsed amperometric detection (HPAEC-PAD) was developed and validated for the simultaneous determination of two Amadori compounds, arginyl-fructose and arginyl-fructosyl-glucose in Korean red ginseng (Panax ginseng) extracts, rat plasma. Separation of the two target analytes was efficiently undertaken on CarboPac PA1 anion-exchange column with isocratic elution (400 mM sodium hydroxide and deionized water (90:10, v/v)) at flow rate 0.7 mL/min within 15 min of single chromatographic run. Under optimized conditions, the detection limits (signal-to-noise ratio equal to 3) were 20 and 25 ng/mL for arginyl-fructose and arginyl-fructosyl-glucose, respectively. Calibration curves of peak area for the two analytes were linear over three orders of magnitude with a correlation coefficients greater than 0.999. The accuracy of the method was tested by recovery measurement of the spiked samples which yielded good results of 94.15-102.62%. This method was successfully applied to the quantification of arginyl-fructose and arginyl-fructosyl-glucose in herbal extracts and in the plasma samples from rat. PMID:18329967

  20. Rapid determination of vitellogenin in fish plasma by anion exchange high performance liquid chromatography using postcolumn fluorescence derivatization with o-phthalaldehyde.

    PubMed

    Wu, Cuiqin; Yuan, Dongxing; Liu, Baomin

    2006-12-01

    An analytical method involving anion exchange high performance liquid chromatographic determination of vitellogenin (Vtg) in fish plasma after postcolumn fluorescence derivatization with o-phthalaldehyde (OPA) was developed. The retention time of Vtg was about 11 min. The reagent variables for derivatization were optimized. The fluorophore was excited at 335 nm and detected at 435 nm. A calibration curve was established ranging from 0.13 to 11.28 microg. The determination limit of Vtg was found to be as low as 0.13 microg. The spiked recovery was 93.6% and interassay variability was less than 4%. The method developed was used to determine Vtg in fish plasma obtained from red sea bream (Pagrosomus major), black porgy (Sparus macrocephalus) and skew band grunt (Hapalogenys nitens), without complicated sample pretreatment. The results confirmed that the method showed advantages of being simple, rapid, reproducible and sensitive. PMID:17159322

  1. Analytical Method for Sugar Profile in Pet Food and Animal Feeds by High-Performance Anion-Exchange Chromatography with Pulsed Amperometric Detection.

    PubMed

    Ellingson, David J; Anderson, Phillip; Berg, Daniel P

    2016-03-01

    There is a need for a standardized, accurate, rugged, and consistent method to measure for sugars in pet foods and animal feeds. Many traditional standard sugar methods exist for other matrixes, but when applied in collaborative studies there was poor agreement and sources of error identified with those standard methods. The advancement in technology over the years has given us the ability to improve on these standard methods of analysis. A method is described here that addresses these common issues and was subjected to a single-laboratory validation to assess performance on a wide variety of pet foods and animal feeds. Of key importance to the method performance is the sample preparation before extraction, type of extraction solvent, postextraction cleanup, and, finally, optimized chromatography using high-performance anion exchange chromatography with pulsed amperometric detection. The results obtained from the validation demonstrate how typical issues seen with these matrixes can influence performance of sugar analysis. The results also demonstrate that this method is fit-for-purpose and can meet the challenges of sugar analysis in pet food and animal feeds to lay the foundation for a standardized method of analysis. PMID:26952902

  2. Characterisation of legumes by enzymatic hydrolysis, microdialysis sampling, and micro-high-performance anion-exchange chromatography with electrospray ionisation mass spectrometry.

    PubMed

    Okatch, Harriet; Torto, Nelson; Armateifio, Joan

    2003-04-11

    An assay based on enzymatic hydrolysisand microdialysis sampling, micro-high-performance anion-exchange chromatography (micro-HPAEC) with electrospray ionisation mass spectrometry (ESI-MS) for the characterisation of legumes is presented. Characterisation of two bean varieties; Phaseolus mungo and P. acutifilous was based upon enzymatic hydrolysis using an endo-beta-mannanase from Aspergillus niger with subsequent analysis of the hydrolysates with HPAEC-MS. The hydrolysates were detected in the positive ionisation mode after desalting the chromatographic effluent, employing a cation-exchange membrane desalting device with water as the regenerating liquid. Mass chromatograms, acquiredafter hydrolysis of both bean samples for 12 h, showed two different profiles of hydrolysates. The P. mungo bean hydrolysate showed the presence of saccharides with a degree of polymerisation (DP) in the range of 2-6, whereas that of P. acutifilous showed only DPs of 2-5. Both bean samples had one type of DP 2, but showed different types of DPs 3, 4 and 5. Only the P. mungo sample showed the presence of DP 6. The most abundant fraction for P. mungo was DP 4, whereas that for P. acutifilous was DP 5. Tandem MS of the hydrolysates showed that the DP 2 hydrolysates observed for the samples were of the same type, having a 1,6 linkage. Also tandem MS data for DPs 3, 4, and 5 showed that similar hydrolysates were present within the same sample as well as among the two samples. The data also showed the existence of 1,6 linkages for DP 3, 4, and 5 hydrolysates. The single enzymatic hydrolysis in combination with microdialysis and HPAEC with ESI-MS proved to be sufficient and reproducible for profiling and showing the difference between the two bean samples. PMID:12735463

  3. Profiling N-linked oligosaccharides from IgG by high-performance anion-exchange chromatography with pulsed amperometric detection.

    PubMed

    Rohrer, Jeffrey S; Basumallick, Lipika; Hurum, Deanna C

    2016-06-01

    Understanding and characterizing protein therapeutic glycosylation is important with growing evidence that glycosylation impacts biological efficacy, pharmacokinetics and cellular toxicity. Protein expression systems and reactor conditions can impact glycosylation, leading to potentially undesirable glycosylation. For example, high-mannose species may be present, which are atypical of human antibody glycosylation. Their presence in the Fc domain has been linked to increased serum clearance of immunoglobulin G (IgG) antibodies. High-performance anion-exchange chromatography with pulsed amperometric detection (HPAE-PAD) is an effective tool for determining glycans present in glycoprotein therapeutics. We report an improved HPAE-PAD method for IgG oligosaccharide separation. The neutral glycans are well resolved, including separation of high-mannose species from typical human IgG glycans. Oligosaccharide identification was performed by comparison to known standards in conjunction with selective exoglycosidase digestion of both standards and released glycans. Retention times (RTs) of known glycans were compared with the retention times of maltose, maltotriose and maltotetraose standards to define a retention index value for each glycan. These retention indices were used to aid identification of glycans from an example monoclonal antibody sample of unknown glycosylation. Method ruggedness was evaluated across duplicate systems, analysts and triplicate column lots. Comparing two systems with different analysts and columns, retention time precision relative standard deviations (RSDs) were between 0.63 and 4.0% while retention indices precision RSDs ranged from 0.27 to 0.56%. The separation is orthogonal to capillary electrophoresis-based separation of labeled IgG oligosaccharides. PMID:26786498

  4. Online determination of levoglucosan in ambient aerosols with Particle-into-Liquid Sampler - High-Performance Anion-Exchange Chromatography - Mass Spectrometry (PILS-HPAEC-MS)

    NASA Astrophysics Data System (ADS)

    Saarnio, K.; Teinilä, K.; Saarikoski, S.; Carbone, S.; Gilardoni, S.; Timonen, H.; Aurela, M.; Hillamo, R.

    2013-06-01

    Biomass burning, such as domestic heating, agricultural, and wild open-land fires, has a significant influence on the atmosphere at the global and, especially, at the local scale. Levoglucosan has been shown to be a good tracer for biomass burning emissions in atmospheric particulate matter and several analytical techniques have been presented for the determination of levoglucosan from filter samples. In this paper, a novel combination of a Particle-into-Liquid Sampler (PILS) to a high-performance anion-exchange chromatograph (HPAEC) with the detection by a mass spectrometer (MS) is presented for the online analysis of levoglucosan in ambient particles. The PILS-HPAEC-MS technique enables a fast online analysis of levoglucosan from the particulate samples. The method was tested at an urban background station in Helsinki, Finland, in winter 2011. A comparison with simultaneous levoglucosan measurements from filter samples by the HPAEC-MS was performed and it showed a good agreement between the online and offline methods. Additionally, the online levoglucosan data were compared with the biomass burning tracer fragments measured by a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS). As there were no local biomass burning sources close to the measurement station, online levoglucosan measurements revealed that most of the particles from biomass burning were either regionally distributed or long-range transported in the urban background of Helsinki. The average levoglucosan concentrations were relatively low (average 0.083 μg m-3) during the measurement campaign. The highest concentration peak measured for levoglucosan (1.4 μg m-3) seemed to originate from biomass burning in Eastern Europe, likely in Estonia, that was transported to Helsinki.

  5. Online determination of levoglucosan in ambient aerosols with particle-into-liquid sampler - high-performance anion-exchange chromatography - mass spectrometry (PILS-HPAEC-MS)

    NASA Astrophysics Data System (ADS)

    Saarnio, K.; Teinilä, K.; Saarikoski, S.; Carbone, S.; Gilardoni, S.; Timonen, H.; Aurela, M.; Hillamo, R.

    2013-10-01

    Biomass burning, such as domestic heating, agricultural, and wild open-land fires, has a significant influence on the atmosphere at the global and, especially, at the local scale. Levoglucosan has been shown to be a good tracer for biomass burning emissions in atmospheric particulate matter, and several analytical techniques have been presented for the determination of levoglucosan from filter samples. In this paper, a novel combination of a particle-into-liquid sampler (PILS) to a high-performance anion-exchange chromatograph (HPAEC) with the detection by a mass spectrometer (MS) is presented for the online analysis of levoglucosan in ambient particles. The PILS-HPAEC-MS technique enables a fast online analysis of levoglucosan from the particulate samples. The method was tested at an urban background station in Helsinki, Finland, in winter 2011. A comparison with simultaneous levoglucosan measurements from filter samples by the HPAEC-MS was performed and it showed a good agreement between the online and offline methods. Additionally, the online levoglucosan data were compared with the biomass burning tracer fragments measured by a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). As there were no local biomass burning sources close to the measurement station, online levoglucosan measurements revealed that most of the particles from biomass burning were either regionally distributed or long-range transported in the urban background of Helsinki. The average levoglucosan concentrations were relatively low (average 0.083 μg m-3) during the measurement campaign. The highest concentration peak measured for levoglucosan (1.4 μg m-3) seemed to originate from biomass burning in the Baltic countries, likely in Estonia, that was transported to Helsinki.

  6. Dextrin characterization by high-performance anion-exchange chromatography--pulsed amperometric detection and size-exclusion chromatography--multi-angle light scattering--refractive index detection.

    PubMed

    White, D Richard; Hudson, Patricia; Adamson, Julie T

    2003-05-16

    Starch hydrolysis products, or dextrins, are widely used throughout the food industry for their functional properties. Dextrins are saccharide polymers linked primarily by alpha-(1 --> 4) D-glucose units and are prepared by partial hydrolysis of starch. Hydrolysis can be accomplished by the use of acid, enzymes, or by a combination of both. The hydrolysis products are typically characterized by the "dextrose equivalent" (DE), which refers to the total reducing power of all sugars present relative to glucose. While the DE gives the supplier and buyer a rough guide to the bulk properties of the material, the physiochemical properties of dextrins are dependent on the overall oligosaccharide profile. High-performance anion-exchange chromatography (HPAEC) with pulsed amperometric detection and size-exclusion chromatography (SEC) with multi-angle light-scattering and refractive index detection were used to characterize dextrins from commercial sources. HPAEC was used to acquire the oligosaccharide profile, and SEC to obtain an overall molar mass distribution. These methods in combination extended our understanding of the relationship between oligosaccharide profile, DE, and the hydrolysis process. Data from the two techniques enabled a method for estimating the DE that gave results in reasonable agreement with the accepted titration method. PMID:12830879

  7. Short communication: Quantification of carbohydrates in whey permeate products using high-performance anion-exchange chromatography with pulsed amperometric detection

    PubMed Central

    Lee, Hyeyoung; de MeloSilva, Vitor Luiz; Liu, Yan

    2016-01-01

    A method was developed for the characterization and quantification of the disaccharide lactose and 3 major bovine milk oligosaccharides (BMO) in dairy streams. Based on high-performance anion-exchange chromatography-pulsed amperometric detection (HPAE-PAD), this method is advantageous because it requires minimal sample preparation and achieves good chromatographic separation of oligosaccharide isomers within 30 min. The linear dynamic range and limit of detection were 0.1 to 10 mg/L and 0.03 to 0.22 mg/L, respectively. Mean recoveries of the BMO were excellent and ranged from 98.4 to 100.4%. Without complicated sample preparation procedures, this HPAE-PAD method measured BMO [3′-sialyllactose (3′SL), 6′-sialyllactose (6′SL), and 6′-sialyllactosamine (6′SLN)] and lactose using a single instrument, therefore increasing the accuracy of the measurement and applicability for the dairy industry. In colostrum whey permeate, 3′SL, 6′SL, and 6′SLN were 94, 29, and 46 mg/L, respectively. This work is the first to demonstrate that some commercial products, currently marketed for supporting a healthy immune system, contain significant amounts of bioactive BMO and therefore, carry additional bioactivities. PMID:26364096

  8. Rapid and sensitive quantification of levoglucosan in aerosols by high-performance anion-exchange chromatography with positive electrospray ionization mass spectrometry (HPAEC-positive ESI-MS)

    NASA Astrophysics Data System (ADS)

    Asakawa, Daichi; Furuichi, Yuko; Yamamoto, Atsushi; Oku, Yuichiro; Funasaka, Kunihiro

    2015-12-01

    A convenient quantification method for underivatized levoglucosan, which is a tracer for biomass burning influenced particulate matter (PM), has been established using high-performance anion-exchange chromatography (HPAEC) coupled to positive electrospray ionization mass spectrometry ((+)ESI-MS). Levoglucosan was chromatographically separated from its isomers (mannosan and galactosan) and detected selectively with positive ESI-MS. Limits of detection and quantification for this method were 0.40 and 1.3 ng mL-1, respectively. A comparison of simultaneous measurements by this method and conventional derivatization gas chromatography/mass spectrometry showed a good linearity with a slope of 1.008 and a determination coefficient of 0.9932. The developed method was applied to ambient suspended particulate matter hourly collected by continuous particulate monitors at 10 stations. The hourly concentration of levoglucosan during August 9-11, 2011, was 1.7-918 ng m-3 and its distribution indicated the transportation of biomass burning aerosols of a forest fire. This is the first report of horizontal distribution of the hourly levoglucosan concentration in Japan.

  9. High-performance liquid chromatographic method for the determination of the anthelmintic nitroxynil in cattle muscle tissue with on-line anion-exchange clean-up.

    PubMed

    Tarbin, J A; Shearer, G

    1993-04-01

    A high-performance liquid chromatographic method for the determination of the anthelmintic nitroxynil has been developed. The drug was extracted from cattle muscle tissue with 1% triethylamine in acetonitrile. The extract was evaporated to dryness and taken up in 0.1 M ammonium acetate-acetonitrile (50:50, v/v). The extract was then injected onto a polymeric anion-exchange precolumn. After clean-up with 0.1 M ammonium acetate-acetonitrile (50:50, v/v) for 5 min, the precolumn was eluted with 1% aqueous trifluoroacetic acid-acetonitrile (50:50, v/v) onto a PLRP-S polymer column and chromatographed with a mobile phase of 0.01 M phosphate pH 7-acetonitrile (80:20, v/v). Detection was by ultraviolet at 273 nm. Average recoveries at four levels from 0.005 to 1.000 mg kg-1 were > 88%. The limit of determination was 0.005 mg kg-1. PMID:8491824

  10. High performance fluorine doped (Sn,Ru)O2 oxygen evolution reaction electro-catalysts for proton exchange membrane based water electrolysis

    NASA Astrophysics Data System (ADS)

    Kadakia, Karan; Datta, Moni Kanchan; Velikokhatnyi, Oleg I.; Jampani, Prashanth; Park, Sung Kyoo; Chung, Sung Jae; Kumta, Prashant N.

    2014-01-01

    Identification of electro-catalysts containing non-noble metal or significantly reduced amounts of expensive noble metals (e.g. RuO2) is highly desirable. Development of such a catalyst with comparable electrochemical performance to the standard noble metal oxide for proton exchange membrane (PEM) based water electrolysis would constitute a pioneering breakthrough in hydrogen generation by water electrolysis. In line with these goals, by exploiting a two-pronged theoretical first principles and experimental approach herein we demonstrate that a nano-structured solid solution of SnO2:10 wt% F containing only 20 at.% RuO2 [e.g. (Sn0.80Ru0.20)O2:10F] displays a remarkably similar electrochemical activity and moreover, comparable or even much improved electrochemical stability and durability compared to pure the noble metal counterpart, RuO2. Density functional theory calculations have demonstrated direct dependence of the catalytic activity on the electronic structure peculiarities of the F-doped (Ru,Sn)O2 which corresponds well with the experimental results.

  11. Isolation of carboxyl-termini and blocked amino-termini of viral proteins by high-performance cation-exchange chromatography.

    PubMed

    Gorman, J J; Shiell, B J

    1993-08-27

    The strong cation-exchanger, PolySulfoethyl Aspartamide, has been assessed as a medium for isolation of carboxyl-terminal and blocked amino-terminal peptides from tryptic digests of small quantities of viral proteins. Peptides with a single positive charge, the blocked amino-terminal peptides of ovalbumin and the Newcastle disease virus (NDV) matrix protein and carboxyl-terminal peptides of ovalbumin and the NDV nucleocapsid protein, eluted in early ion-exchange fractions and were readily isolated in homogeneous form by subsequent reversed-phase HPLC. Some early ion-exchange fractions also contained singly charged peptides derived by "chymotryptic-like" cleavage, whilst other peptides eluted in these fractions due to their highly acidic character. Terminal sequences with additional basic residues were isolated from later eluting ion-exchange fractions. Peptides with this property included the blocked amino-terminus of the NDV nucleocapsid protein and a portion of the carboxyl-terminus of the NDV matrix protein. Hitherto undescribed polymorphism in the amino-terminal region of ovalbumin was revealed in this study. Truncated peptides from the carboxyl-terminus of the NDV matrix protein were also detected. The presence of these peptides could be a reflection of carboxyl-terminal processing of the matrix protein. The strategy described herein should be of general utility for selective microisolation of carboxyl-terminal peptides and blocked amino-terminal peptides from tryptic digests of proteins. PMID:8408428

  12. Determination of nitric oxide metabolites, nitrate and nitrite, in Anopheles culicifacies mosquito midgut and haemolymph by anion exchange high-performance liquid chromatography: plausible mechanism of refractoriness

    PubMed Central

    Sharma, Arun; Raghavendra, Kamaraju; Adak, Tridibesh; Dash, Aditya P

    2008-01-01

    Background The diverse physiological and pathological role of nitric oxide in innate immune defenses against many intra and extracellular pathogens, have led to the development of various methods for determining nitric oxide (NO) synthesis. NO metabolites, nitrite (NO2-) and nitrate (NO3-) are produced by the action of an inducible Anopheles culicifacies NO synthase (AcNOS) in mosquito mid-guts and may be central to anti-parasitic arsenal of these mosquitoes. Method While exploring a plausible mechanism of refractoriness based on nitric oxide synthase physiology among the sibling species of An. culicifacies, a sensitive, specific and cost effective high performance liquid chromatography (HPLC) method was developed, which is not influenced by the presence of biogenic amines, for the determination of NO2- and NO3- from mosquito mid-guts and haemolymph. Results This method is based on extraction, efficiency, assay reproducibility and contaminant minimization. It entails de-proteinization by centrifugal ultra filtration through ultracel 3 K filter and analysis by high performance anion exchange liquid chromatography (Sphereclone, 5 μ SAX column) with UV detection at 214 nm. The lower detection limit of the assay procedure is 50 pmoles in all midgut and haemolymph samples. Retention times for NO2- and NO3- in standards and in mid-gut samples were 3.42 and 4.53 min. respectively. Assay linearity for standards ranged between 50 nM and 1 mM. Recoveries of NO2- and NO3- from spiked samples (1–100 μM) and from the extracted standards (1–100 μM) were calculated to be 100%. Intra-assay and inter assay variations and relative standard deviations (RSDs) for NO2- and NO3- in spiked and un-spiked midgut samples were 5.7% or less. Increased levels NO2- and NO3- in midguts and haemolymph of An. culicifacies sibling species B in comparison to species A reflect towards a mechanism of refractoriness based on AcNOS physiology. Conclusion HPLC is a sensitive and accurate technique

  13. Enabling Detailed Energy Analyses via the Technology Performance Exchange: Preprint

    SciTech Connect

    Studer, D.; Fleming, K.; Lee, E.; Livingood, W.

    2014-08-01

    One of the key tenets to increasing adoption of energy efficiency solutions in the built environment is improving confidence in energy performance. Current industry practices make extensive use of predictive modeling, often via the use of sophisticated hourly or sub-hourly energy simulation programs, to account for site-specific parameters (e.g., climate zone, hours of operation, and space type) and arrive at a performance estimate. While such methods are highly precise, they invariably provide less than ideal accuracy due to a lack of high-quality, foundational energy performance input data. The Technology Performance Exchange was constructed to allow the transparent sharing of foundational, product-specific energy performance data, and leverages significant, external engineering efforts and a modular architecture to efficiently identify and codify the minimum information necessary to accurately predict product energy performance. This strongly-typed database resource represents a novel solution to a difficult and established problem. One of the most exciting benefits is the way in which the Technology Performance Exchange's application programming interface has been leveraged to integrate contributed foundational data into the Building Component Library. Via a series of scripts, data is automatically translated and parsed into the Building Component Library in a format that is immediately usable to the energy modeling community. This paper (1) presents a high-level overview of the project drivers and the structure of the Technology Performance Exchange; (2) offers a detailed examination of how technologies are incorporated and translated into powerful energy modeling code snippets; and (3) examines several benefits of this robust workflow.

  14. Performance, Performance System, and High Performance System

    ERIC Educational Resources Information Center

    Jang, Hwan Young

    2009-01-01

    This article proposes needed transitions in the field of human performance technology. The following three transitions are discussed: transitioning from training to performance, transitioning from performance to performance system, and transitioning from learning organization to high performance system. A proposed framework that comprises…

  15. High pressure ceramic heat exchanger

    DOEpatents

    Harkins, Bruce D.; Ward, Michael E.

    1998-01-01

    Many recuperators have components which react to corrosive gases and are used in applications where the donor fluid includes highly corrosive gases. These recuperators have suffered reduced life, increased service or maintenance, and resulted in increased cost. The present header assembly when used with recuperators reduces the brittle effect of a portion of the ceramic components. Thus, the present header assembly used with the present recuperator increases the life, reduces the service and maintenance, and reduces the increased cost associated with corrosive action of components used to manufacture recuperators. The present header assembly is comprised of a first ceramic member, a second ceramic member, a strengthening reinforcing member being in spaced relationship to the first ceramic member and the second ceramic member. The header assembly is further comprised of a refractory material disposed in contacting relationship with the first ceramic member, the second ceramic member and the strengthening reinforcing member. The present header assembly provides a high strength load bearing header assembly having good thermal cycling characteristics, good resistance to a corrosive environment and good steady state strength at elevated temperatures.

  16. High pressure ceramic heat exchanger

    DOEpatents

    Harkins, Bruce D.; Ward, Michael E.

    1999-01-01

    Many recuperators have components which react to corrosive gases and are used in applications where the donor fluid includes highly corrosive gases. These recuperators have suffered reduced life, increased service or maintenance, and resulted in increased cost. The present header assembly when used with recuperators reduces the brittle effect of a portion of the ceramic components. Thus, the present header assembly used with the present recuperator increases the life, reduces the service and maintenance, and reduces the increased cost associated with corrosive action of components used to manufacture recuperators. The present header assembly is comprised of a first ceramic member, a second ceramic member, a reinforcing member being in spaced relationship to the first ceramic member and the second ceramic member. The header assembly is further comprised of a refractory material disposed in contacting relationship with the first ceramic member, the second ceramic member and the reinforcing member and having a strengthening member wrapped around the refractory material. The present header assembly provides a high strength load bearing header assembly having good thermal cycling characteristics, good resistance to a corrosive environment and good steady state strength at elevated temperatures.

  17. High pressure ceramic heat exchanger

    DOEpatents

    Harkins, B.D.; Ward, M.E.

    1998-09-22

    Many recuperators have components which react to corrosive gases and are used in applications where the donor fluid includes highly corrosive gases. These recuperators have suffered reduced life, increased service or maintenance, and resulted in increased cost. The present header assembly when used with recuperators reduces the brittle effect of a portion of the ceramic components. Thus, the present header assembly used with the present recuperator increases the life, reduces the service and maintenance, and reduces the increased cost associated with corrosive action of components used to manufacture recuperators. The present header assembly is comprised of a first ceramic member, a second ceramic member, a strengthening reinforcing member being in spaced relationship to the first ceramic member and the second ceramic member. The header assembly is further comprised of a refractory material disposed in contacting relationship with the first ceramic member, the second ceramic member and the strengthening reinforcing member. The present header assembly provides a high strength load bearing header assembly having good thermal cycling characteristics, good resistance to a corrosive environment and good steady state strength at elevated temperatures. 5 figs.

  18. Informational exchange between different highly organized systems

    NASA Astrophysics Data System (ADS)

    Panovkin, B. N.

    The conditions under which information exchange is possible between different highly organized systems are considered in relation to problems of establishing informational contact with extraterrestrial civilizations. It is pointed out that the basis for mutual understanding among terrestrial societies has been the commonality of the subject relationship to the material and social world, which influences both articulation and cognitive processes. A model of information exchange between highly organized systems (automata) making use of different schemes for the classification of the objects of activity is then examined. It is shown that, in the most favorable case, information exchange is possible between actively interacting systems in direct contact according to a high-rank reflexive game with verification.

  19. Heparin identification test and purity test for OSCS in heparin sodium and heparin calcium by weak anion-exchange high-performance liquid chromatography.

    PubMed

    Hashii, Noritaka; Kawasaki, Nana; Itoh, Satsuki; Qin, Yan; Fujita, Naho; Hattori, Toshiaki; Miyata, Kazuyoshi; Bando, Aya; Sekimoto, Yuko; Hama, Takeshi; Kashimura, Masaki; Tatsumi, Masashi; Mabuchi, Kazunori; Namekawa, Hiroshi; Sakai, Toru; Hirose, Mio; Dobashi, Sei; Shimahashi, Hirotoshi; Koyama, Sadatoshi; Herr, Susanne Odgaard; Kawai, Kenzo; Yoden, Hikaru; Yamaguchi, Teruhide

    2010-09-01

    Heparin sodium and heparin calcium, which are widely used as anti-coagulants, are known to potentially contain the natural impurity dermatan sulfate (DS). Recently serious adverse events occurred in patients receiving heparin sodium in the US, and a contaminant oversulfated chondroitin sulfate (OSCS) was found to be a cause of the events. To ensure the quality and safety of pharmaceutical heparins, there is need of a physicochemical identification test that can discriminate heparin from the heparin-related substances as well as a sensitive purity test for OSCS. Recently, HPLC with a strong-anion exchange column was proposed as the methods for identifying heparin and determination of OSCS in heparin sodium. Although this method is convenient and easy to perform, the only column suitable for this purpose is the Dionex IonPac AS11-HC column. In this study, we developed alternative identification test and test for OSCS in both heparin sodium and heparin calcium using a weak anion-exchange column. The identification test allowed for separation of heparin from the impurity DS and contaminant OSCS in a shorter time. The purity test provided enough sensitivity, specificity, linearity, recovery and repeatability for OSCS. We believe that our methods will be useful for quality control of pharmaceutical heparins. PMID:20452241

  20. Improved high performance liquid chromatographic separation of anthocyanin compounds from grapes using a novel mixed-mode ion-exchange reversed-phase column.

    PubMed

    McCallum, Jason L; Yang, Raymond; Young, J Christopher; Strommer, Judith N; Tsao, Rong

    2007-04-27

    A novel mixed mode HPLC method using a column combining both ion-exchange and reversed-phase separation mechanisms has been developed to facilitate analysis of anthocyanins in grapes. Chromatographic performance and subsequent analysis of anthocyanidin diglucosides and acylated compounds are significantly improved using the new column, compared to those associated with conventional C18 reversed-phase methods. The mixed mode column produces a distinctive eluting pattern for the different anthocyanin subgroups, avoiding overlaps found with C18 columns. The enhanced chromatographic resolution provides nearly complete separation of 37 anthocyanin types, and permits detection of delphinidin 3-O-(6''-O-caffeoyl) beta-D-glucoside for the first time in extracts of skins from Concord grapes. PMID:17382950

  1. A Pd/C-CeO2 Anode Catalyst for High-Performance Platinum-Free Anion Exchange Membrane Fuel Cells.

    PubMed

    Miller, Hamish A; Lavacchi, Alessandro; Vizza, Francesco; Marelli, Marcello; Di Benedetto, Francesco; D'Acapito, Francesco; Paska, Yair; Page, Miles; Dekel, Dario R

    2016-05-10

    One of the biggest obstacles to the dissemination of fuel cells is their cost, a large part of which is due to platinum (Pt) electrocatalysts. Complete removal of Pt is a difficult if not impossible task for proton exchange membrane fuel cells (PEM-FCs). The anion exchange membrane fuel cell (AEM-FC) has long been proposed as a solution as non-Pt metals may be employed. Despite this, few examples of Pt-free AEM-FCs have been demonstrated with modest power output. The main obstacle preventing the realization of a high power density Pt-free AEM-FC is sluggish hydrogen oxidation (HOR) kinetics of the anode catalyst. Here we describe a Pt-free AEM-FC that employs a mixed carbon-CeO2 supported palladium (Pd) anode catalyst that exhibits enhanced kinetics for the HOR. AEM-FC tests run on dry H2 and pure air show peak power densities of more than 500 mW cm(-2) . PMID:27062251

  2. The joint effects of personality and workplace social exchange relationships in predicting task performance and citizenship performance.

    PubMed

    Kamdar, Dishan; Van Dyne, Linn

    2007-09-01

    This field study examines the joint effects of social exchange relationships at work (leader-member exchange and team-member exchange) and employee personality (conscientiousness and agreeableness) in predicting task performance and citizenship performance. Consistent with trait activation theory, matched data on 230 employees, their coworkers, and their supervisors demonstrated interactions in which high quality social exchange relationships weakened the positive relationships between personality and performance. Results demonstrate the benefits of consonant predictions in which predictors and outcomes are matched on the basis of specific targets. We discuss theoretical and practical implications. PMID:17845086

  3. Borate-aided anion exchange high-performance liquid chromatography of uridine diphosphate-sugars in brain, heart, adipose and liver tissues.

    PubMed

    Oikari, Sanna; Venäläinen, Tuula; Tammi, Markku

    2014-01-01

    In this paper we describe a method optimized for the purification of uridine diphosphate (UDP)-sugars from liver, adipose tissue, brain, and heart, with highly reproducible up to 85% recoveries. Rapid tissue homogenization in cold ethanol, lipid removal by butanol extraction, and purification with a graphitized carbon column resulted in isolation of picomolar quantities of the UDP-sugars from 10 to 30mg of tissue. The UDP-sugars were baseline separated from each other, and from all major nucleotides using a CarboPac PA1 anion exchange column eluted with a gradient of acetate and borate buffers. The extraction and purification protocol produced samples with few unidentified peaks. UDP-N-acetylglucosamine was a dominant UDP-sugar in all the rat tissues studied. However, brain and adipose tissue showed high UDP-glucose levels, equal to that of UDP-N-acetylglucosamine. The UDP-N-acetylglucosamine showed 2.3-2.7 times higher levels than UDP-N-acetylgalactosamine in all tissues, and about the same ratio was found between UDP-glucose and UDP-galactose in adipose tissue and brain (2.6 and 2.8, respectively). Interestingly, the UDP-glucose/UDP-galactose ratio was markedly lower in liver (1.1) and heart (1.7). The UDP-N-acetylglucosamine/UDP-glucuronic acid ratio was also constant, between 9.7 and 7.7, except in liver with the ratio as low as 1.8. The distinct UDP-glucose/galactose ratio, and the abundance of UDP-glucuronic acid may reflect the specific role of liver in glycogen synthesis, and metabolism of hormones and xenobiotics, respectively, using these UDP-sugars as substrates. PMID:24309714

  4. EXCHANGE

    SciTech Connect

    Boltz, J.C.

    1992-09-01

    EXCHANGE is published monthly by the Idaho National Engineering Laboratory (INEL), a multidisciplinary facility operated for the US Department of Energy (DOE). The purpose of EXCHANGE is to inform computer users about about recent changes and innovations in both the mainframe and personal computer environments and how these changes can affect work being performed at DOE facilities.

  5. Anion-exchange high-performance liquid chromatography with post-column detection for the analysis of phytic acid and other inositol phosphates

    NASA Technical Reports Server (NTRS)

    Rounds, M. A.; Nielsen, S. S.; Mitchell, C. A. (Principal Investigator)

    1993-01-01

    The use of gradient anion-exchange HPLC, with a simple post-column detection system, is described for the separation of myo-inositol phosphates, including "phytic acid" (myo-inositol hexaphosphate). Hexa-, penta-, tetra-, tri- and diphosphate members of this homologous series are clearly resolved within 30 min. This method should facilitate analysis and quantitation of "phytic acid" and other inositol phosphates in plant, food, and soil samples.

  6. High performance polymer development

    NASA Technical Reports Server (NTRS)

    Hergenrother, Paul M.

    1991-01-01

    The term high performance as applied to polymers is generally associated with polymers that operate at high temperatures. High performance is used to describe polymers that perform at temperatures of 177 C or higher. In addition to temperature, other factors obviously influence the performance of polymers such as thermal cycling, stress level, and environmental effects. Some recent developments at NASA Langley in polyimides, poly(arylene ethers), and acetylenic terminated materials are discussed. The high performance/high temperature polymers discussed are representative of the type of work underway at NASA Langley Research Center. Further improvement in these materials as well as the development of new polymers will provide technology to help meet NASA future needs in high performance/high temperature applications. In addition, because of the combination of properties offered by many of these polymers, they should find use in many other applications.

  7. Optimization of Transient Heat Exchanger Performance for Improved Energy Efficiency

    NASA Astrophysics Data System (ADS)

    Bran Anleu, Gabriela; Kavehpour, Pirouz; Lavine, Adrienne; Wirz, Richard

    2014-11-01

    Heat exchangers are used in a multitude of applications within systems for energy generation, energy conversion, or energy storage. Many of these systems (e.g. solar power plants) function under transient conditions, but the design of the heat exchangers is typically optimized assuming steady state conditions. There is a potential for significant energy savings if the transient behavior of the heat exchanger is taken into account in designing the heat exchanger by optimizing its operating conditions in relation to the transient behavior of the overall system. The physics of the transient behavior of a heat exchanger needs to be understood to provide design parameters for transient heat exchangers to deliver energy savings. A numerical model was used to determine the optimized mass flow rates thermal properties for a thermal energy storage system. The transient behavior is strongly linked to the dimensionless parameters relating fluid properties, the mass flow rates, and the temperature of the fluids at the inlet of each stream. Smart metals, or advanced heat exchanger surface geometries and methods of construction will be used to meet the three goals mentioned before: 1) energy and cost reduction, 2) size reduction, and 3) optimal performance for all modes of operation.

  8. Aerodynamics of heat exchangers for high-altitude aircraft

    NASA Technical Reports Server (NTRS)

    Drela, Mark

    1996-01-01

    Reduction of convective beat transfer with altitude dictates unusually large beat exchangers for piston- engined high-altitude aircraft The relatively large aircraft drag fraction associated with cooling at high altitudes makes the efficient design of the entire heat exchanger installation an essential part of the aircraft's aerodynamic design. The parameters that directly influence cooling drag are developed in the context of high-altitude flight Candidate wing airfoils that incorporate heat exchangers are examined. Such integrated wing-airfoil/heat-exchanger installations appear to be attractive alternatives to isolated heat.exchanger installations. Examples are drawn from integrated installations on existing or planned high-altitude aircraft.

  9. Production of high-performance and improved-durability Pt-catalyst /support for proton-exchange-membrane fuel cells with pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Huang, Ting-Wei; Qayyum, Hamza; Lin, Guan-Ren; Chen, Szu-yuan; Tseng, Chung-Jen

    2016-06-01

    Pulsed laser deposition in Ar atmosphere is used to deposit Pt nanoparticles onto gas diffusion layer, and its application to proton-exchange-membrane fuel cell is optimized and characterized. When used at anode side, with a Pt loading of 17 μg cm‑2 the fuel-cell current density at 0.6 V reaches 1.08 A cm‑2, which is close to that of a cell with the anode made by conventional slurry process using E-TEK Pt /C of 200 μg cm‑2 Pt loading. The usage of Pt is decreased by 12 fold. Such a low usage of Pt prepared by pulsed laser deposition can be ascribed to the prevention of forming isolated regions that occurs with Pt /C slurry, good dispersion of Pt particles on support, and small particle sizes of 2–3 nm. Furthermore, using accelerated degradation test, it is found that the pulsed laser deposition sample retains 60% of its initial electrochemical surface area after 5000 potential cycles, much higher than that with E-TEK Pt /C, which retains only 7% of its initial electrochemical surface area. The higher electrochemical durability can be attributed to the higher degree of graphitization in the gas diffusion layer used as compared with the carbon black in E-TEK Pt /C, which leads to stronger binding of the Pt nanoparticles onto the carbon support and stronger corrosion resistance of the carbon support.

  10. 2011 PERFORMANCE ASSESSMENT COMMUNITY OF PRACTICE TECHNICAL EXCHANGE - SUMMARY

    SciTech Connect

    Seitz, R.

    2011-12-30

    The Performance Assessment Community of Practice (PA CoP) was developed in 2008 to improve consistency and quality in the preparation of performance assessments (PAs) and risk assessments across the Department of Energy (DOE) Complex. The term, PA, is used to represent all of these modeling applications in this report. The PA CoP goals are to foster the exchange of information among PA practitioners and to share lessons learned from PAs conducted for DOE, commercial disposal facilities, and international entities. Technical exchanges and workshops are a cornerstone of PA CoP activities. Previous technical exchanges have addressed Engineered Barriers (2009 - http://www.cresp.org/education/workshops/pacop/), the Advanced Simulation Capability for Environmental Management and the Cementitious Barriers Partnership (2010 - http://srnl.doe.gov/copexchange/links.htm). Each technical exchange also includes summary presentations regarding activities at DOE, the Nuclear Regulatory Commission (NRC) and other organizations (e.g., International Atomic Energy Agency (IAEA)) as well as a number of presentations from selected sites to provide insight and perspective from on-going modeling activities. Through the deployment of PA Assistance Teams, the PA CoP has also been engaged in the development of new PAs across the DOE Complex. As a way of improving consistency in the preparation of new PAs, the teams provide technical advice and share experiences, noteworthy practices, and lessons learned from previous Low-Level Waste Disposal Facility Federal Review Group (LFRG) reviews. Teams have provided support for PAs at Hanford, Idaho, Paducah and Portsmouth. The third annual PA CoP Technical Exchange was held on May 25-26, 2011 in Atlanta, GA. The PA CoP Steering Committee Meeting held its first meeting on May 24 prior to the Technical Exchange. Decision making using models and software quality assurance were the topical emphasis for the exchange. A new feature at the 2011 technical

  11. New reversed phase-high performance liquid chromatographic method for selective separation of yttrium from all rare earth elements employing nitrilotriacetate complexes in anion exchange mode.

    PubMed

    Dybczyński, Rajmund S; Kulisa, Krzysztof; Pyszynska, Marta; Bojanowska-Czajka, Anna

    2015-03-20

    Separation of Y from other rare earth elements (REE) is difficult because of similarity of its ionic radius to ionic radii of Tb, Dy and Ho. In the new RP-HPLC system with C18 column, tetra-n-butyl ammonium hydroxide (TBAOH) as an ion interaction reagent (IIR), nitrilotriacetic acid (NTA) as a complexing agent at pH=2.8-3.5, and post column derivatization with Arsenazo III, yttrium is eluted in the region of light REE, between Nd and Sm and is base line separated from Nd and Sm and even from promethium. Simple model employing literature data on complex formation of REE with NTA and based on anion exchange mechanism was developed to foresee the order of elution of individual REE. The model correctly predicted that lanthanides up to Tb will be eluted in the order of increasing Atomic Number (At.No.) but all heavier REE will show smaller retention factors than Tb. Concurrent UV/VIS detection at 658nm and the use of radioactive tracers together with γ-ray spectrometric measurements made possible to establish an unique elution order of elution of REE: La, Ce, Pr, Nd, Pm, Y, Sm, Er, Ho, Tm, Yb, Eu, Lu, Dy+Gd, Tb, Sc. The real place of Y however, in this elution series differs from that predicted by the model (Y between Sm and Eu). The method described in this work enables selective separation of Y from La, Ce, Pr, Nd, Pm, Sm and all heavier REE treated as a group. PMID:25700726

  12. A high-performance, safer and semi-automated approach for the delta18O analysis of diatom silica and new methods for removing exchangeable oxygen.

    PubMed

    Chapligin, B; Meyer, H; Friedrichsen, H; Marent, A; Sohns, E; Hubberten, H-W

    2010-09-15

    The determination of the oxygen isotope composition of diatom silica in sediment cores is important for paleoclimate reconstruction, especially in non-carbonate sediments, where no other bioindicators such as ostracods and foraminifera are available. Since most currently available analytical techniques are time-consuming and labour-intensive, we have developed a new, safer, faster and semi-automated online approach for measuring oxygen isotopes in biogenic silica. Improvements include software that controls the measurement procedures and a video camera that remotely records the reaction of the samples under BrF(5) with a CO(2) laser. Maximum safety is guaranteed as the laser-fluorination unit is arranged under a fume hood in a separate room from the operator. A new routine has been developed for removing the exchangeable hydrous components within biogenic silica using ramp degassing. The sample plate is heated up to 1100 degrees C and cooled down to 400 degrees C in approximately 7 h under a flow of He gas (the inert Gas Flow Dehydration method--iGFD) before isotope analysis. Two quartz and two biogenic silica samples (approximately 1.5 mg) of known isotope composition were tested. The isotopic compositions were reproducible within an acceptable error; quartz samples gave a mean standard deviation of <0.15 per thousand (1sigma) and for biogenic silica <0.25 per thousand (1sigma) for samples down to approximately 0.3 mg. The semi-automated fluorination line is the fastest method available at present and enables a throughput of 74 samples/week. PMID:20740543

  13. High performance systems

    SciTech Connect

    Vigil, M.B.

    1995-03-01

    This document provides a written compilation of the presentations and viewgraphs from the 1994 Conference on High Speed Computing given at the High Speed Computing Conference, {open_quotes}High Performance Systems,{close_quotes} held at Gleneden Beach, Oregon, on April 18 through 21, 1994.

  14. High Performance Polymers

    NASA Technical Reports Server (NTRS)

    Venumbaka, Sreenivasulu R.; Cassidy, Patrick E.

    2003-01-01

    This report summarizes results from research on high performance polymers. The research areas proposed in this report include: 1) Effort to improve the synthesis and to understand and replicate the dielectric behavior of 6HC17-PEK; 2) Continue preparation and evaluation of flexible, low dielectric silicon- and fluorine- containing polymers with improved toughness; and 3) Synthesis and characterization of high performance polymers containing the spirodilactam moiety.

  15. ION EXCHANGE PERFORMANCE OF TITANOSILICATES, GERMANATES AND CARBON NANOTUBES

    SciTech Connect

    Alsobrook, A. N.; Hobbs, D. T.

    2013-04-24

    This report presents a summary of testing the affinity of titanosilicates (TSP), germanium-substituted titanosilicates (Ge-TSP) and multiwall carbon nanotubes (MWCNT) for lanthanide ions in dilute nitric acid solution. The K-TSP ion exchanger exhibited the highest affinity for lanthanides in dilute nitric acid solutions. The Ge-TSP ion exchanger shows promise as a material with high affinity, but additional tests are needed to confirm the preliminary results. The MWCNT exhibited much lower affinities than the K-TSP in dilute nitric acid solutions. However, the MWCNT are much more chemically stable to concentrated nitric acid solutions and, therefore, may candidates for ion exchange in more concentrated nitric acid solutions. This technical report serves as the deliverable documenting completion of the FY13 research milestone, M4FT-13SR0303061 – measure actinide and lanthanide distribution values in nitric acid solutions with sodium and potassium titanosilicate materials.

  16. Nutrient loading alters the performance of key nutrient exchange mutualisms.

    PubMed

    Shantz, Andrew A; Lemoine, Nathan P; Burkepile, Deron E

    2016-01-01

    Nutrient exchange mutualisms between phototrophs and heterotrophs, such as plants and mycorrhizal fungi or symbiotic algae and corals, underpin the functioning of many ecosystems. These relationships structure communities, promote biodiversity and help maintain food security. Nutrient loading may destabilise these mutualisms by altering the costs and benefits each partner incurs from interacting. Using meta-analyses, we show a near ubiquitous decoupling in mutualism performance across terrestrial and marine environments in which phototrophs benefit from enrichment at the expense of their heterotrophic partners. Importantly, heterotroph identity, their dependence on phototroph-derived C and the type of nutrient enrichment (e.g. nitrogen vs. phosphorus) mediated the responses of different mutualisms to enrichment. Nutrient-driven changes in mutualism performance may alter community organisation and ecosystem processes and increase costs of food production. Consequently, the decoupling of nutrient exchange mutualisms via alterations of the world's nitrogen and phosphorus cycles may represent an emerging threat of global change. PMID:26549314

  17. High effectiveness contour matching contact heat exchanger

    NASA Technical Reports Server (NTRS)

    Blakely, Robert L. (Inventor); Roebelen, George J., Jr. (Inventor); Davenport, Arthur K. (Inventor)

    1988-01-01

    There is a need in the art for a heat exchanger design having a flexible core providing contour matching capabilities, which compensates for manufacturing tolerance and distortion buildups, and which accordingly furnishes a relatively uniform thermal contact conductance between the core and external heat sources under essentially all operating conditions. The core of the heat exchanger comprises a top plate and a bottom plate, each having alternate rows of pins attached. Each of the pins fits into corresponding tight-fitting recesses in the opposite plate.

  18. High effectiveness contour matching contact heat exchanger

    NASA Astrophysics Data System (ADS)

    Blakely, Robert L.; Roebelen, George J., Jr.; Davenport, Arthur K.

    1988-08-01

    There is a need in the art for a heat exchanger design having a flexible core providing contour matching capabilities, which compensates for manufacturing tolerance and distortion buildups, and which accordingly furnishes a relatively uniform thermal contact conductance between the core and external heat sources under essentially all operating conditions. The core of the heat exchanger comprises a top plate and a bottom plate, each having alternate rows of pins attached. Each of the pins fits into corresponding tight-fitting recesses in the opposite plate.

  19. High performance polymeric foams

    SciTech Connect

    Gargiulo, M.; Sorrentino, L.; Iannace, S.

    2008-08-28

    The aim of this work was to investigate the foamability of high-performance polymers (polyethersulfone, polyphenylsulfone, polyetherimide and polyethylenenaphtalate). Two different methods have been used to prepare the foam samples: high temperature expansion and two-stage batch process. The effects of processing parameters (saturation time and pressure, foaming temperature) on the densities and microcellular structures of these foams were analyzed by using scanning electron microscopy.

  20. Heat exchanger with transpired, highly porous fins

    DOEpatents

    Kutscher, Charles F.; Gawlik, Keith

    2002-01-01

    The heat exchanger includes a fin and tube assembly with increased heat transfer surface area positioned within a hollow chamber of a housing to provide effective heat transfer between a gas flowing within the hollow chamber and a fluid flowing in the fin and tube assembly. A fan is included to force a gas, such as air, to flow through the hollow chamber and through the fin and tube assembly. The fin and tube assembly comprises fluid conduits to direct the fluid through the heat exchanger, to prevent mixing with the gas, and to provide a heat transfer surface or pathway between the fluid and the gas. A heat transfer element is provided in the fin and tube assembly to provide extended heat transfer surfaces for the fluid conduits. The heat transfer element is corrugated to form fins between alternating ridges and grooves that define flow channels for directing the gas flow. The fins are fabricated from a thin, heat conductive material containing numerous orifices or pores for transpiring the gas out of the flow channel. The grooves are closed or only partially open so that all or substantially all of the gas is transpired through the fins so that heat is exchanged on the front and back surfaces of the fins and also within the interior of the orifices, thereby significantly increasing the available the heat transfer surface of the heat exchanger. The transpired fins also increase heat transfer effectiveness of the heat exchanger by increasing the heat transfer coefficient by disrupting boundary layer development on the fins and by establishing other beneficial gas flow patterns, all at desirable pressure drops.

  1. High performance parallel architectures

    SciTech Connect

    Anderson, R.E. )

    1989-09-01

    In this paper the author describes current high performance parallel computer architectures. A taxonomy is presented to show computer architecture from the user programmer's point-of-view. The effects of the taxonomy upon the programming model are described. Some current architectures are described with respect to the taxonomy. Finally, some predictions about future systems are presented. 5 refs., 1 fig.

  2. High-Performance Happy

    ERIC Educational Resources Information Center

    O'Hanlon, Charlene

    2007-01-01

    Traditionally, the high-performance computing (HPC) systems used to conduct research at universities have amounted to silos of technology scattered across the campus and falling under the purview of the researchers themselves. This article reports that a growing number of universities are now taking over the management of those systems and…

  3. START High Performance Discharges

    NASA Astrophysics Data System (ADS)

    Gates, D. A.

    1997-11-01

    . Analysis of the confinement properties of the discharge and a discussion of the scaling of confinement with global plasma parameters will be presented. Comparisons are made between the predictions of neoclassical transport theory and ion temperature measurements from a charge exchange spectrometer. These results indicate the ability of spherical tokamaks to support high β operation with good confinement. Experiments in the MAST (Mega Amp Spherical Tokamak) device, currently under construction, will demonstrate spherical tokamak operations for significantly longer pulse lengths at high ( ~1-2MA) plasma current.

  4. High Performance, Dependable Multiprocessor

    NASA Technical Reports Server (NTRS)

    Ramos, Jeremy; Samson, John R.; Troxel, Ian; Subramaniyan, Rajagopal; Jacobs, Adam; Greco, James; Cieslewski, Grzegorz; Curreri, John; Fischer, Michael; Grobelny, Eric; George, Alan; Aggarwal, Vikas; Patel, Minesh; Some, Raphael

    2006-01-01

    With the ever increasing demand for higher bandwidth and processing capacity of today's space exploration, space science, and defense missions, the ability to efficiently apply commercial-off-the-shelf (COTS) processors for on-board computing is now a critical need. In response to this need, NASA's New Millennium Program office has commissioned the development of Dependable Multiprocessor (DM) technology for use in payload and robotic missions. The Dependable Multiprocessor technology is a COTS-based, power efficient, high performance, highly dependable, fault tolerant cluster computer. To date, Honeywell has successfully demonstrated a TRL4 prototype of the Dependable Multiprocessor [I], and is now working on the development of a TRLS prototype. For the present effort Honeywell has teamed up with the University of Florida's High-performance Computing and Simulation (HCS) Lab, and together the team has demonstrated major elements of the Dependable Multiprocessor TRLS system.

  5. Performance of a Thermoelectric Device with Integrated Heat Exchangers

    NASA Astrophysics Data System (ADS)

    Barry, Matthew M.; Agbim, Kenechi A.; Chyu, Minking K.

    2015-06-01

    Thermoelectric devices (TEDs) convert heat directly into electrical energy, making them well suited for waste heat recovery applications. An integrated thermoelectric device (iTED) is a restructured TED that allows more heat to enter the p-n junctions, thus producing a greater power output . An iTED has heat exchangers incorporated into the hot-side interconnectors with flow channels directing the working fluid through the heat exchangers. The iTED was constructed of p- and n-type bismuth-telluride semiconductors and copper interconnectors and rectangular heat exchangers. The performance of the iTED in terms of , produced voltage and current , heat input and conversion efficiency for various flow rates (), inlet temperatures (C) ) and load resistances () with a constant cold-side temperature ( = 0C) was conducted experimentally. An increase in had a greater effect on the performance than did an increase in . A 3-fold increase in resulted in a 3.2-, 3.1-, 9.7-, 3.5- and 2.8-fold increase in and respectively. For a constant of 50C, a 3-fold increase in from 3300 to 9920 resulted in 1.6-, 1.6-, 2.6-, 1.5- and 1.9-fold increases in , , , and respectively.

  6. High performance steam development

    SciTech Connect

    Duffy, T.; Schneider, P.

    1995-12-31

    DOE has launched a program to make a step change in power plant to 1500 F steam, since the highest possible performance gains can be achieved in a 1500 F steam system when using a topping turbine in a back pressure steam turbine for cogeneration. A 500-hour proof-of-concept steam generator test module was designed, fabricated, and successfully tested. It has four once-through steam generator circuits. The complete HPSS (high performance steam system) was tested above 1500 F and 1500 psig for over 102 hours at full power.

  7. Fast speciation of mercury in seawater by short-column high-performance liquid chromatography hyphenated to inductively coupled plasma spectrometry after on-line cation exchange column preconcentration.

    PubMed

    Jia, Xiao-Yu; Gong, Di-Rong; Han, Yi; Wei, Chao; Duan, Tai-Cheng; Chen, Hang-Ting

    2012-01-15

    A simple and fast method for trace speciation analysis of mercury (Hg(2+)), methylmercury (MeHg(+)) and ethylmercury (EtHg(+)) in seawater has been developed by short-column high-performance liquid chromatography hyphenated to inductively coupled plasma spectrometry (HPLC-ICP-MS) after on-line cation-exchange column (CEC) preconcentration. The analytes were firstly adsorbed on the CEC without any extraneous reagent, and then were eluted rapidly (within seconds) and completely with a very low concentration of l-cysteine solution, which provides the conveniency for the on-line coupling of the preconcentration method and detection technique. To our best knowledge, it is for the first time to employ the CEC preconcentration technique to trap all of the three mercury species simultaneously at their positive charged status for the purpose of speciation analysis. Under the optimized conditions, a very high preconcentration factor up to 1250 has been obtained with 30mL sample solution, which leads to the very low detection limits of 0.042ngL(-1) for Hg(2+), 0.016ngL(-1) for MeHg(+) and 0.008ngL(-1) for EtHg(+) (as Hg), respectively. With the established method, three seawater samples were also analyzed, and all the three mercury species have been found in each sample, albeit at a very low concentration. PMID:22265565

  8. A Novel Methodology to Synthesize Highly Conductive Anion Exchange Membranes

    NASA Astrophysics Data System (ADS)

    He, Yubin; Pan, Jiefeng; Wu, Liang; Zhu, Yuan; Ge, Xiaolin; Ran, Jin; Yang, Zhengjin; Xu, Tongwen

    2015-08-01

    Alkaline polyelectrolyte fuel cell now receives growing attention as a promising candidate to serve as the next generation energy-generating device by enabling the use of non-precious metal catalysts (silver, cobalt, nickel et al.). However, the development and application of alkaline polyelectrolyte fuel cell is still blocked by the poor hydroxide conductivity of anion exchange membranes. In order to solve this problem, we demonstrate a methodology for the preparation of highly OH- conductive anion exchange polyelectrolytes with good alkaline tolerance and excellent dimensional stability. Polymer backbones were grafted with flexible aliphatic chains containing two or three quaternized ammonium groups. The highly flexible and hydrophilic multi-functionalized side chains prefer to aggregate together to facilitate the formation of well-defined hydrophilic-hydrophobic microphase separation, which is crucial for the superior OH- conductivity of 69 mS/cm at room temperature. Besides, the as-prepared AEMs also exhibit excellent alkaline tolerance as well as improved dimensional stability due to their carefully designed polymer architecture, which provide new directions to pursue high performance AEMs and are promising to serve as a candidate for fuel cell technology.

  9. A Novel Methodology to Synthesize Highly Conductive Anion Exchange Membranes

    PubMed Central

    He, Yubin; Pan, Jiefeng; Wu, Liang; Zhu, Yuan; Ge, Xiaolin; Ran, Jin; Yang, ZhengJin; Xu, Tongwen

    2015-01-01

    Alkaline polyelectrolyte fuel cell now receives growing attention as a promising candidate to serve as the next generation energy-generating device by enabling the use of non-precious metal catalysts (silver, cobalt, nickel et al.). However, the development and application of alkaline polyelectrolyte fuel cell is still blocked by the poor hydroxide conductivity of anion exchange membranes. In order to solve this problem, we demonstrate a methodology for the preparation of highly OH− conductive anion exchange polyelectrolytes with good alkaline tolerance and excellent dimensional stability. Polymer backbones were grafted with flexible aliphatic chains containing two or three quaternized ammonium groups. The highly flexible and hydrophilic multi-functionalized side chains prefer to aggregate together to facilitate the formation of well-defined hydrophilic-hydrophobic microphase separation, which is crucial for the superior OH− conductivity of 69 mS/cm at room temperature. Besides, the as-prepared AEMs also exhibit excellent alkaline tolerance as well as improved dimensional stability due to their carefully designed polymer architecture, which provide new directions to pursue high performance AEMs and are promising to serve as a candidate for fuel cell technology. PMID:26311616

  10. High Performance FORTRAN

    NASA Technical Reports Server (NTRS)

    Mehrotra, Piyush

    1994-01-01

    High performance FORTRAN is a set of extensions for FORTRAN 90 designed to allow specification of data parallel algorithms. The programmer annotates the program with distribution directives to specify the desired layout of data. The underlying programming model provides a global name space and a single thread of control. Explicitly parallel constructs allow the expression of fairly controlled forms of parallelism in particular data parallelism. Thus the code is specified in a high level portable manner with no explicit tasking or communication statements. The goal is to allow architecture specific compilers to generate efficient code for a wide variety of architectures including SIMD, MIMD shared and distributed memory machines.

  11. High Performance Window Retrofit

    SciTech Connect

    Shrestha, Som S; Hun, Diana E; Desjarlais, Andre Omer

    2013-12-01

    The US Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy (EERE) and Traco partnered to develop high-performance windows for commercial building that are cost-effective. The main performance requirement for these windows was that they needed to have an R-value of at least 5 ft2 F h/Btu. This project seeks to quantify the potential energy savings from installing these windows in commercial buildings that are at least 20 years old. To this end, we are conducting evaluations at a two-story test facility that is representative of a commercial building from the 1980s, and are gathering measurements on the performance of its windows before and after double-pane, clear-glazed units are upgraded with R5 windows. Additionally, we will use these data to calibrate EnergyPlus models that we will allow us to extrapolate results to other climates. Findings from this project will provide empirical data on the benefits from high-performance windows, which will help promote their adoption in new and existing commercial buildings. This report describes the experimental setup, and includes some of the field and simulation results.

  12. Ion exhange and molecular sorption of oxalic acid with a highly basic anion exchanger

    NASA Astrophysics Data System (ADS)

    Krisilova, E. V.; Oros, G. Yu.; Krisilov, A. V.; Selemenev, V. F.

    2014-04-01

    Ab initio modeling of a matrix fragment of resin and geometry optimization of the molecular structure of oxalic acid were performed. The isotherm of oxalic acid sorption with AV-17-8 anion exchange resin was obtained by the variable concentrations technique. The ion-exchange and molecular components of sorbate fixation with the ion exchanger were determined. The hydration of the highly basic anion exchanger that absorbed different quantities of dicarboxylic acid was evaluated by the centrifuging method. The dependence of the amount of water and sorbate concentration in the resin was linear antibatic.

  13. Fabrication of High-Temperature Heat Exchangers by Plasma Spraying Exterior Skins on Nickel Foams

    NASA Astrophysics Data System (ADS)

    Hafeez, P.; Yugeswaran, S.; Chandra, S.; Mostaghimi, J.; Coyle, T. W.

    2016-06-01

    Thermal-sprayed heat exchangers were tested at high temperatures (750 °C), and their performances were compared to the foam heat exchangers made by brazing Inconel sheets to their surface. Nickel foil was brazed to the exterior surface of 10-mm-thick layers of 10 and 40 PPI nickel foam. A plasma torch was used to spray an Inconel coating on the surface of the foil. A burner test rig was built to produce hot combustion gases that flowed over exposed face of the heat exchanger. Cooling air flowed through the foam heat exchanger at rates of up to 200 SLPM. Surface temperature and air inlet/exit temperature were measured. Heat transfer to air flowing through the foam was significantly higher for the thermally sprayed heat exchangers than for the brazed heat exchangers. On an average, thermally sprayed heat exchangers show 36% higher heat transfer than conventionally brazed foam heat exchangers. At low flow rates, the convective resistance is large (~4 × 10-2 m2 K/W), and the effect of thermal contact resistance is negligible. At higher flow rates, the convective resistance decreases (~2 × 10-3 m2 K/W), and the lower contact resistance of the thermally sprayed heat exchanger provides better performance than the brazed heat exchangers.

  14. Fabrication of High-Temperature Heat Exchangers by Plasma Spraying Exterior Skins on Nickel Foams

    NASA Astrophysics Data System (ADS)

    Hafeez, P.; Yugeswaran, S.; Chandra, S.; Mostaghimi, J.; Coyle, T. W.

    2016-05-01

    Thermal-sprayed heat exchangers were tested at high temperatures (750 °C), and their performances were compared to the foam heat exchangers made by brazing Inconel sheets to their surface. Nickel foil was brazed to the exterior surface of 10-mm-thick layers of 10 and 40 PPI nickel foam. A plasma torch was used to spray an Inconel coating on the surface of the foil. A burner test rig was built to produce hot combustion gases that flowed over exposed face of the heat exchanger. Cooling air flowed through the foam heat exchanger at rates of up to 200 SLPM. Surface temperature and air inlet/exit temperature were measured. Heat transfer to air flowing through the foam was significantly higher for the thermally sprayed heat exchangers than for the brazed heat exchangers. On an average, thermally sprayed heat exchangers show 36% higher heat transfer than conventionally brazed foam heat exchangers. At low flow rates, the convective resistance is large (~4 × 10-2 m2 K/W), and the effect of thermal contact resistance is negligible. At higher flow rates, the convective resistance decreases (~2 × 10-3 m2 K/W), and the lower contact resistance of the thermally sprayed heat exchanger provides better performance than the brazed heat exchangers.

  15. Silicon carbide for high-temperature heat exchangers

    NASA Astrophysics Data System (ADS)

    Penty, R. A.; Bjerklie, J. W.

    1982-02-01

    It is noted that ceramic heat exchangers are now being used industrially in low-pressure applications, such as recuperators and air preheaters, and that serious consideration is being given to using ceramic materials for high-pressure heat exchangers. The principal advantage of using ceramic heat exchangers in the candidate applications is the potential for higher temperature service or increased life over that obtainable with metallic exchangers. Silicon carbide-based materials are now in service in many areas. The use of low-pressure ceramic recuperators constructed of silicon carbide has demonstrated fuel savings exceeding 40% in high-temperature industrial furnaces. At a material temperature of 1375 C, the demonstrated lifetime of some silicon carbide tubes is 12 to 15 months. The availability of silicon carbide materials is discussed, together with properties required for designing reliable heat exchangers. Attention is also given to the usual failure mode encountered in the field.

  16. High Performance Buildings Database

    DOE Data Explorer

    The High Performance Buildings Database is a shared resource for the building industry, a unique central repository of in-depth information and data on high-performance, green building projects across the United States and abroad. The database includes information on the energy use, environmental performance, design process, finances, and other aspects of each project. Members of the design and construction teams are listed, as are sources for additional information. In total, up to twelve screens of detailed information are provided for each project profile. Projects range in size from small single-family homes or tenant fit-outs within buildings to large commercial and institutional buildings and even entire campuses. The database is a data repository as well. A series of Web-based data-entry templates allows anyone to enter information about a building project into the database. Once a project has been submitted, each of the partner organizations can review the entry and choose whether or not to publish that particular project on its own Web site.

  17. High Performance Liquid Chromatography

    NASA Astrophysics Data System (ADS)

    Talcott, Stephen

    High performance liquid chromatography (HPLC) has many applications in food chemistry. Food components that have been analyzed with HPLC include organic acids, vitamins, amino acids, sugars, nitrosamines, certain pesticides, metabolites, fatty acids, aflatoxins, pigments, and certain food additives. Unlike gas chromatography, it is not necessary for the compound being analyzed to be volatile. It is necessary, however, for the compounds to have some solubility in the mobile phase. It is important that the solubilized samples for injection be free from all particulate matter, so centrifugation and filtration are common procedures. Also, solid-phase extraction is used commonly in sample preparation to remove interfering compounds from the sample matrix prior to HPLC analysis.

  18. Application of high-performance anion-exchange chromatography-pulsed amperometric detection for measuring carbohydrates in routine daily filter samples collected by a national network: 2. Examination of sugar alcohols/polyols, sugars, and anhydrosugars in the upper Midwest

    NASA Astrophysics Data System (ADS)

    Sullivan, A. P.; Frank, N.; Kenski, D. M.; Collett, J. L., Jr.

    2011-04-01

    Carbohydrate measurements of ambient samples can provide insights into the biogenic fraction of the organic carbon (OC) aerosol. However, lack of measurement on a routine basis limits data analysis. In a companion paper, 1 year of archived 1-in-6 day FRM (Federal Reference Monitor) filter samples from the PM2.5 NAAQS compliance monitoring network collected at 10 sites in the upper Midwest were analyzed using high-performance anion-exchange chromatography with pulsed amperometric detection to determine the regional impact of biomass burning. Along with levoglucosan, 13 other carbohydrates were simultaneously measured, including two more anhydrosugars (mannosan and galactosan), five sugars (arabinose, galactose, glucose, mannose, xylose), and six sugar alcohols/polyols (glycerol, methyltetrols, threitol/erythritol, xylitol, sorbitol, mannitol). This paper focuses on the results from these carbohydrates in order to investigate their sources and trends both spatially and temporally. Mannosan, galactosan, arabinose, xylose, and threitol/erythritol all correlated with levoglucosan (R2 from 0.43 to 0.97), suggesting biomass burning as their main source. Glucose and mannitol exhibited higher concentrations in summer and at more southern sites, likely due to vegetation differences at the sites. Using mannitol, the contribution of spores to OC was found to be <1%. Methyltetrols were highly correlated with water-soluble OC (R2 from 0.63 to 0.95) and in higher concentrations at more eastern sites. This spatial pattern is possibly due to these sites being downwind of the high isoprene emission zones that occur in the western part of the Midwest from oak forests in the Ozarks and spruce forests in the northern lake states.

  19. High Performance Work Practices and Firm Performance.

    ERIC Educational Resources Information Center

    Department of Labor, Washington, DC. Office of the American Workplace.

    A literature survey established that a substantial amount of research has been conducted on the relationship between productivity and the following specific high performance work practices: employee involvement in decision making, compensation linked to firm or worker performance, and training. According to these studies, high performance work…

  20. Airside performances of finned eight-tube heat exchangers

    NASA Astrophysics Data System (ADS)

    Li, Cheng; Li, Junming

    2016-01-01

    For applications in the relatively low temperature refrigeration systems with large constant temperature bath, the present work performed the experimental studies on the airside performances of the staggered finned eight-tube heat exchangers with large fin pitches. The airside heat transfer coefficients and pressure drops for three fin types and two fin pitches are obtained and analyzed. The heat transfer enhancement with louver fins is 11-16 % higher than the flat fins and that with sinusoidal corrugated fins is 1.1-3.4 % higher than the flat fins. Higher Re brings larger enhancement for various fins. Fin pitches show weak influence on heat transfer for eight tube rows. However, effects of fin pitch on heat transfer for both the sinusoidal corrugation and the louvered fin are larger than the flat fins and they are different from those for N ≤ 6. Airside Colburn j factor are compared with previous and it could be concluded that the airside j factor is almost constant for finned tube heat exchangers with eight tubes and large fin pitches, when Re is from 250 to 2500. The results are different from previous studies for fewer tube rows.

  1. High-temperature self-circulating thermoacoustic heat exchanger

    NASA Astrophysics Data System (ADS)

    Backhaus, S.; Swift, G. W.; Reid, R. S.

    2005-07-01

    Thermoacoustic and Stirling engines and refrigerators use heat exchangers to transfer heat between the oscillating flow of their thermodynamic working fluids and external heat sources and sinks. An acoustically driven heat-exchange loop uses an engine's own pressure oscillations to steadily circulate its own thermodynamic working fluid through a physically remote high-temperature heat source without using moving parts, allowing for a significant reduction in the cost and complexity of thermoacoustic and Stirling heat exchangers. The simplicity and flexibility of such heat-exchanger loops will allow thermoacoustic and Stirling machines to access diverse heat sources and sinks. Measurements of the temperatures at the interface between such a heat-exchange loop and the hot end of a thermoacoustic-Stirling engine are presented. When the steady flow is too small to flush out the mixing chamber in one acoustic cycle, the heat transfer to the regenerator is excellent, with important implications for practical use.

  2. High performance sapphire windows

    NASA Technical Reports Server (NTRS)

    Bates, Stephen C.; Liou, Larry

    1993-01-01

    High-quality, wide-aperture optical access is usually required for the advanced laser diagnostics that can now make a wide variety of non-intrusive measurements of combustion processes. Specially processed and mounted sapphire windows are proposed to provide this optical access to extreme environment. Through surface treatments and proper thermal stress design, single crystal sapphire can be a mechanically equivalent replacement for high strength steel. A prototype sapphire window and mounting system have been developed in a successful NASA SBIR Phase 1 project. A large and reliable increase in sapphire design strength (as much as 10x) has been achieved, and the initial specifications necessary for these gains have been defined. Failure testing of small windows has conclusively demonstrated the increased sapphire strength, indicating that a nearly flawless surface polish is the primary cause of strengthening, while an unusual mounting arrangement also significantly contributes to a larger effective strength. Phase 2 work will complete specification and demonstration of these windows, and will fabricate a set for use at NASA. The enhanced capabilities of these high performance sapphire windows will lead to many diagnostic capabilities not previously possible, as well as new applications for sapphire.

  3. Secondary Heat Exchanger Design and Comparison for Advanced High Temperature Reactor

    SciTech Connect

    Piyush Sabharwall; Ali Siahpush; Michael McKellar; Michael Patterson; Eung Soo Kim

    2012-06-01

    The goals of next generation nuclear reactors, such as the high temperature gas-cooled reactor and advance high temperature reactor (AHTR), are to increase energy efficiency in the production of electricity and provide high temperature heat for industrial processes. The efficient transfer of energy for industrial applications depends on the ability to incorporate effective heat exchangers between the nuclear heat transport system and the industrial process heat transport system. The need for efficiency, compactness, and safety challenge the boundaries of existing heat exchanger technology, giving rise to the following study. Various studies have been performed in attempts to update the secondary heat exchanger that is downstream of the primary heat exchanger, mostly because its performance is strongly tied to the ability to employ more efficient conversion cycles, such as the Rankine super critical and subcritical cycles. This study considers two different types of heat exchangers—helical coiled heat exchanger and printed circuit heat exchanger—as possible options for the AHTR secondary heat exchangers with the following three different options: (1) A single heat exchanger transfers all the heat (3,400 MW(t)) from the intermediate heat transfer loop to the power conversion system or process plants; (2) Two heat exchangers share heat to transfer total heat of 3,400 MW(t) from the intermediate heat transfer loop to the power conversion system or process plants, each exchanger transfers 1,700 MW(t) with a parallel configuration; and (3) Three heat exchangers share heat to transfer total heat of 3,400 MW(t) from the intermediate heat transfer loop to the power conversion system or process plants. Each heat exchanger transfers 1,130 MW(t) with a parallel configuration. A preliminary cost comparison will be provided for all different cases along with challenges and recommendations.

  4. High power density proton exchange membrane fuel cells

    NASA Technical Reports Server (NTRS)

    Murphy, Oliver J.; Hitchens, G. Duncan; Manko, David J.

    1993-01-01

    Proton exchange membrane (PEM) fuel cells use a perfluorosulfonic acid solid polymer film as an electrolyte which simplifies water and electrolyte management. Their thin electrolyte layers give efficient systems of low weight, and their materials of construction show extremely long laboratory lifetimes. Their high reliability and their suitability for use in a microgravity environment makes them particularly attractive as a substitute for batteries in satellites utilizing high-power, high energy-density electrochemical energy storage systems. In this investigation, the Dow experimental PEM (XUS-13204.10) and unsupported high platinum loading electrodes yielded very high power densities, of the order of 2.5 W cm(exp -2). A platinum black loading of 5 mg per cm(exp 2) was found to be optimum. On extending the three-dimensional reaction zone of fuel cell electrodes by impregnating solid polymer electrolyte into the electrode structures, Nafion was found to give better performance than the Dow experimental PEM. The depth of penetration of the solid polymer electrolyte into electrode structures was 50-70 percent of the thickness of the platinum-catalyzed active layer. However, the degree of platinum utilization was only 16.6 percent and the roughness factor of a typical electrode was 274.

  5. High Performance Work Systems and Firm Performance.

    ERIC Educational Resources Information Center

    Kling, Jeffrey

    1995-01-01

    A review of 17 studies of high-performance work systems concludes that benefits of employee involvement, skill training, and other high-performance work practices tend to be greater when new methods are adopted as part of a consistent whole. (Author)

  6. A new method for separation and determination of Cr(III) and Cr(VI) in water samples by high-performance liquid chromatography based on anion exchange stationary phase of ionic liquid modified silica.

    PubMed

    Sadeghi, Susan; Moghaddam, Ali Zeraatkar

    2015-12-01

    In this work, N-methylimidazolium-chloride ionic liquid functionalized silica was prepared and used as an anion-exchange stationary phase for separation of chromium species by high-performance liquid chromatography (HPLC) with UV detection at 200 nm. The Cr(VI) as HCr2O7(-) and chelated Cr(III) with potassium hydrogen phthalate (PHP) as Cr(PHP)2 (-) was retained on the prepared column and separated using a mobile phase composed of 5% methanol in 25 mM phosphate buffer at pH 6.5. Several variables affecting the chelation/separation steps were modeled by response surface methodology (RSM) using Box-Behnken (BBD) design. The significance of the independent variables and their interactions were tested by the analysis of variances (ANOVA) with 95% confidence limit. Under the optimized conditions, the Cr(III) and Cr(VI) anionic species were well separated with a single peak for each Cr species at retention times of 2.3 and 4.3 min, respectively. The relationship between the peak area and concentration was linear in the range of 0.025-30 for Cr(III) and 0.5-20 mg L(-1) for Cr(VI) with detection limits of 0.010 and 0.210 mg L(-1) for Cr(III) and Cr(VI), respectively. The proposed method was validated by simultaneous separation and determination of the Cr species in tap and underground water samples without impose to any pretreatment. PMID:26526699

  7. Effects of exchange coupling between cap layer and oxide layer on the recording performance in perpendicular media

    NASA Astrophysics Data System (ADS)

    Zhang, Kezhao; Choe, Gunn; Duan, Shanlin

    2009-04-01

    To understand the effects of exchange coupling between the CoCr-alloy cap layer and the CoCrPt-oxide layer in perpendicular media, we measured switching dynamics and recording performances of a series of media with various exchange-coupling layer thicknesses on a high-precision spinstand. This study shows that the cap and the oxide layers have different switching dynamics and sufficiently strong exchange coupling is necessary for adequate thermal stability. Exchange coupling improves the signal-to-noise ratio (SNR) through improved writability and reduced noise from the cap. In the strong coupling region, overwrite and write widths can be varied without loss in SNR.

  8. High Performance Network Monitoring

    SciTech Connect

    Martinez, Jesse E

    2012-08-10

    Network Monitoring requires a substantial use of data and error analysis to overcome issues with clusters. Zenoss and Splunk help to monitor system log messages that are reporting issues about the clusters to monitoring services. Infiniband infrastructure on a number of clusters upgraded to ibmon2. ibmon2 requires different filters to report errors to system administrators. Focus for this summer is to: (1) Implement ibmon2 filters on monitoring boxes to report system errors to system administrators using Zenoss and Splunk; (2) Modify and improve scripts for monitoring and administrative usage; (3) Learn more about networks including services and maintenance for high performance computing systems; and (4) Gain a life experience working with professionals under real world situations. Filters were created to account for clusters running ibmon2 v1.0.0-1 10 Filters currently implemented for ibmon2 using Python. Filters look for threshold of port counters. Over certain counts, filters report errors to on-call system administrators and modifies grid to show local host with issue.

  9. An Empirical Examination of the Mechanisms Mediating between High-Performance Work Systems and the Performance of Japanese Organizations

    ERIC Educational Resources Information Center

    Takeuchi, Riki; Lepak, David P.; Wang, Heli; Takeuchi, Kazuo

    2007-01-01

    The resource-based view of the firm and social exchange perspectives are invoked to hypothesize linkages among high-performance work systems, collective human capital, the degree of social exchange in an establishment, and establishment performance. The authors argue that high-performance work systems generate a high level of collective human…

  10. High temperature polymers for proton exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Einsla, Brian Russel

    Novel proton exchange membranes (PEMs) were investigated that show potential for operating at higher temperatures in both direct methanol (DMFC) and H 2/air PEM fuel cells. The need for thermally stable polymers immediately suggests the possibility of heterocyclic polymers bearing appropriate ion conducting sites. Accordingly, monomers and random disulfonated poly(arylene ether) copolymers containing either naphthalimide, benzoxazole or benzimidazole moieties were synthesized via direct copolymerization. The ion exchange capacity (IEC) was varied by simply changing the ratio of disulfonated monomer to nonsulfonated monomer in the copolymerization step. Water uptake and proton conductivity of cast membranes increased with IEC. The water uptake of these heterocyclic copolymers was lower than that of comparable disulfonated poly(arylene ether) systems, which is a desirable improvement for PEMs. Membrane electrode assemblies were prepared and the initial fuel cell performance of the disulfonated polyimide and polybenzoxazole (PBO) copolymers was very promising at 80°C compared to the state-of-the-art PEM (NafionRTM); nevertheless these membranes became brittle under operating conditions. Several series of poly(arylene ether)s based on disodium-3,3'-disulfonate-4,4 '-dichlorodiphenylsulfone (S-DCDPS) and a benzimidazole-containing bisphenol were synthesized and afforded copolymers with enhanced stability. Selected properties of these membranes were compared to separately prepared miscible blends of disulfonated poly(arylene ether sulfone) copolymers and polybenzimidazole (PBI). Complexation of the sulfonic acid groups with the PBI structure reduced water swelling and proton conductivity. The enhanced proton conductivity of NafionRTM membranes has been proposed to be due to the aggregation of the highly acidic side-chain sulfonic acid sites to form ion channels. A series of side-chain sulfonated poly(arylene ether sulfone) copolymers based on methoxyhydroquinone was

  11. Commoditization of High Performance Storage

    SciTech Connect

    Studham, Scott S.

    2004-04-01

    The commoditization of high performance computers started in the late 80s with the attack of the killer micros. Previously, high performance computers were exotic vector systems that could only be afforded by an illustrious few. Now everyone has a supercomputer composed of clusters of commodity processors. A similar commoditization of high performance storage has begun. Commodity disks are being used for high performance storage, enabling a paradigm change in storage and significantly changing the price point of high volume storage.

  12. High Performance Computing Today

    SciTech Connect

    Dongarra, Jack; Meuer,Hans; Simon,Horst D.; Strohmaier,Erich

    2000-04-01

    In last 50 years, the field of scientific computing has seen a rapid change of vendors, architectures, technologies and the usage of systems. Despite all these changes the evolution of performance on a large scale however seems to be a very steady and continuous process. Moore's Law is often cited in this context. If the authors plot the peak performance of various computers of the last 5 decades in Figure 1 that could have been called the supercomputers of their time they indeed see how well this law holds for almost the complete lifespan of modern computing. On average they see an increase in performance of two magnitudes of order every decade.

  13. High-throughput charge exchange recombination spectroscopy system on MAST

    SciTech Connect

    Conway, N. J.; Carolan, P. G.; McCone, J.; Walsh, M. J.; Wisse, M.

    2006-10-15

    A major upgrade to the charge exchange recombination spectroscopy system on MAST has recently been implemented. The new system consists of a high-throughput spectrometer coupled to a total of 224 spatial channels, including toroidal and poloidal views of both neutral heating beams on MAST. Radial resolution is {approx}1 cm, comparable to the ion Larmor radius. The toroidal views are configured with 64 channels per beam, while the poloidal views have 32 channels per beam. Background channels for both poloidal and toroidal views are also provided. A large transmission grating is at the heart of the new spectrometer, with high quality single lens reflex lenses providing excellent imaging performance and permitting the full exploitation of the available etendue of the camera sensor. The charge-coupled device camera chosen has four-tap readout at a maximum aggregate speed of 8.8 MHz, and it is capable of reading out the full set of 224 channels in less than 4 ms. The system normally operates at 529 nm, viewing the C{sup 5+} emission line, but can operate at any wavelength in the range of 400-700 nm. Results from operating the system on MAST are shown, including impurity ion temperature and velocity profiles. The system's excellent spatial resolution is ideal for the study of transport barrier phenomena on MAST, an activity which has already been advanced significantly by data from the new diagnostic.

  14. An empirical examination of the mechanisms mediating between high-performance work systems and the performance of Japanese organizations.

    PubMed

    Takeuchi, Riki; Lepak, David P; Wang, Heli; Takeuchi, Kazuo

    2007-07-01

    The resource-based view of the firm and social exchange perspectives are invoked to hypothesize linkages among high-performance work systems, collective human capital, the degree of social exchange in an establishment, and establishment performance. The authors argue that high-performance work systems generate a high level of collective human capital and encourage a high degree of social exchange within an organization, and that these are positively related to the organization's overall performance. On the basis of a sample of Japanese establishments, the results provide support for the existence of these mediating mechanisms through which high-performance work systems affect overall establishment performance. PMID:17638466

  15. High effectiveness liquid droplet/gas heat exchanger for space power applications

    NASA Technical Reports Server (NTRS)

    Bruckner, A. P.; Mattick, A. T.

    1983-01-01

    A high-effectiveness liquid droplet/gas heat exchanger (LDHX) concept for thermal management in space is described. Heat is transferred by direct contact between fine droplets (approximately 100-300 microns in diameter) of a suitable low vapor pressure liquid and an inert working gas. Complete separation of the droplet and gas media in the zero-g environment is accomplished by configuring the LDHX as a vortex chamber.The large heat transfer area presented by the small droplets permits heat exchanger effectiveness of 0.9-0.95 in a compact, lightweight geometry which avoids many of the limitations of conventional plate and fin or tube and shell heat exchangers, such as their tendency toward single point failure. The application of the LDHX in a high temperature Brayton cycle is discussed to illustrate the performance and operational characteristics of this new heat exchanger concept.

  16. High effectiveness liquid droplet/gas heat exchanger for space power applications

    NASA Technical Reports Server (NTRS)

    Bruckner, A. P.; Mattick, A. T.

    1983-01-01

    A high-effectiveness liquid droplet/gas heat exchanger (LDHX) concept for thermal management in space is described. Heat is transferred by direct contact between fine droplets (approx. 100 to 300 micron diameter) of a suitable low vapor pressure liquid and an inert working gas. Complete separation of the droplet and gas media in the zero-g environment is accomplished by configuring the LDHX as a vortex chamber. The large heat transfer area presented by the small droplets permits heat exchanger effectiveness of 0.9 to 0.95 in a compact, lightweight geometry which avoids many of the limitations of conventional plate and fin or tube and shell heat exchangers, such as their tendency toward single point failure. The application of the LDHX in a high temperature Bryaton cycle is discussed to illustrate the performance and operational characteristics of this heat exchanger concept.

  17. High Voltage TAL Performance

    NASA Technical Reports Server (NTRS)

    Jacobson, David T.; Jankovsky, Robert S.; Rawlin, Vincent K.; Manzella, David H.

    2001-01-01

    The performance of a two-stage, anode layer Hall thruster was evaluated. Experiments were conducted in single and two-stage configurations. In single-stage configuration, the thruster was operated with discharge voltages ranging from 300 to 1700 V. Discharge specific impulses ranged from 1630 to 4140 sec. Thruster investigations were conducted with input power ranging from 1 to 8.7 kW, corresponding to power throttling of nearly 9: 1. An extensive two-stage performance map was generated. Data taken with total voltage (sum of discharge and accelerating voltage) constant revealed a decrease in thruster efficiency as the discharge voltage was increased. Anode specific impulse values were comparable in the single and two-stage configurations showing no strong advantage for two-stage operation.

  18. High Performance Arcjet Engines

    NASA Technical Reports Server (NTRS)

    Kennel, Elliot B.; Ivanov, Alexey Nikolayevich; Nikolayev, Yuri Vyacheslavovich

    1994-01-01

    This effort sought to exploit advanced single crystal tungsten-tantalum alloy material for fabrication of a high strength, high temperature arcjet anode. The use of this material is expected to result in improved strength, temperature resistance, and lifetime compared to state of the art polycrystalline alloys. In addition, the use of high electrical and thermal conductivity carbon-carbon composites was considered, and is believed to be a feasible approach. Highly conductive carbon-carbon composite anode capability represents enabling technology for rotating-arc designs derived from the Russian Scientific Research Institute of Thermal Processes (NIITP) because of high heat fluxes at the anode surface. However, for US designs the anode heat flux is much smaller, and thus the benefits are not as great as in the case of NIITP-derived designs. Still, it does appear that the tensile properties of carbon-carbon can be even better than those of single crystal tungsten alloys, especially when nearly-single-crystal fibers such as vapor grown carbon fiber (VGCF) are used. Composites fabricated from such materials must be coated with a refractory carbide coating in order to ensure compatibility with high temperature hydrogen. Fabrication of tungsten alloy single crystals in the sizes required for fabrication of an arcjet anode has been shown to be feasible. Test data indicate that the material can be expected to be at least the equal of W-Re-HfC polycrystalline alloy in terms of its tensile properties, and possibly superior. We are also informed by our colleagues at Scientific Production Association Luch (NP0 Luch) that it is possible to use Russian technology to fabricate polycrystalline W-Re-HfC or other high strength alloys if desired. This is important because existing engines must rely on previously accumulated stocks of these materials, and a fabrication capability for future requirements is not assured.

  19. High performance cyclone development

    SciTech Connect

    Giles, W.B.

    1981-01-01

    The results of cold flow experiments at atmospheric conditions of an air-shielded 18 in-dia electrocyclone with a central cusped electrode are reported using fine test dusts of both flyash and nickel powder. These results are found to confirm expectations of enhanced performance, similar to earlier work on a 12 in-dia model. An analysis of the combined inertial-electrostatic force field is also presented which identifies general design goals and scaling laws. From this, it is found that electrostatic enhancement will be particularly beneficial for fine dusts in large cyclones. Recommendations for further improvement in cyclone collection efficiency are proposed.

  20. Tough high performance composite matrix

    NASA Technical Reports Server (NTRS)

    Pater, Ruth H. (Inventor); Johnston, Norman J. (Inventor)

    1994-01-01

    This invention is a semi-interpentrating polymer network which includes a high performance thermosetting polyimide having a nadic end group acting as a crosslinking site and a high performance linear thermoplastic polyimide. Provided is an improved high temperature matrix resin which is capable of performing in the 200 to 300 C range. This resin has significantly improved toughness and microcracking resistance, excellent processability, mechanical performance, and moisture and solvent resistances.

  1. OTEC-1 power system test program: performance of one-megawatt heat exchangers

    SciTech Connect

    Lorenz, J.J.; Yung, D.; Howard, P.A.; Panchal, C.B.; Poucher, F.W.

    1981-11-01

    Heat exchanger test results for the first deployment of OTEC-1 are reported. These tests were aimed at evaluating the performance of a state-of-the-art, 1-MWe titanium shell-and-tube evaporator and condenser in an ocean environment. The evaporator consisted of both a plain and an enhanced (Union Carbide High Flux) tube bundle, whereas the condenser had plain tubes only. All tests with the evaporator were conducted in the sprayed-bundle mode. Experimental results for the condenser and plain-tube portion of the evaporator were in excellent agreement with performance predictions. This result demonstrates that the thermal performance of large plain-tube heat exchangers can be predicted with a high level of confidence. However, the performance of the enhanced-tube portion of the evaporator was much lower thn predicted. Evidence strongly suggested that this poor performance was attributable mainly to fouling of the High Flux surface by corrosion products consisting predominantly of hydrated aluminum oxides.

  2. High Voltage SPT Performance

    NASA Technical Reports Server (NTRS)

    Manzella, David; Jacobson, David; Jankovsky, Robert

    2001-01-01

    A 2.3 kW stationary plasma thruster designed to operate at high voltage was tested at discharge voltages between 300 and 1250 V. Discharge specific impulses between 1600 and 3700 sec were demonstrated with thrust between 40 and 145 mN. Test data indicated that discharge voltage can be optimized for maximum discharge efficiency. The optimum discharge voltage was between 500 and 700 V for the various anode mass flow rates considered. The effect of operating voltage on optimal magnet field strength was investigated. The effect of cathode flow rate on thruster efficiency was considered for an 800 V discharge.

  3. High performance steam development

    SciTech Connect

    Duffy, T.; Schneider, P.

    1995-10-01

    Over 30 years ago U.S. industry introduced the world`s highest temperature (1200{degrees}F at 5000 psig) and most efficient power plant, the Eddystone coal-burning steam plant. The highest alloy material used in the plant was 316 stainless steel. Problems during the first few years of operation caused a reduction in operating temperature to 1100{degrees}F which has generally become the highest temperature used in plants around the world. Leadership in high temperature steam has moved to Japan and Europe over the last 30 years.

  4. Foundation Heat Exchanger Final Report: Demonstration, Measured Performance, and Validated Model and Design Tool

    SciTech Connect

    Hughes, Patrick; Im, Piljae

    2012-04-01

    Geothermal heat pumps, sometimes called ground-source heat pumps (GSHPs), have been proven capable of significantly reducing energy use and peak demand in buildings. Conventional equipment for controlling the temperature and humidity of a building, or supplying hot water and fresh outdoor air, must exchange energy (or heat) with the building's outdoor environment. Equipment using the ground as a heat source and heat sink consumes less non-renewable energy (electricity and fossil fuels) because the earth is cooler than outdoor air in summer and warmer in winter. The most important barrier to rapid growth of the GSHP industry is high first cost of GSHP systems to consumers. The most common GSHP system utilizes a closed-loop ground heat exchanger. This type of GSHP system can be used almost anywhere. There is reason to believe that reducing the cost of closed-loop systems is the strategy that would achieve the greatest energy savings with GSHP technology. The cost premium of closed-loop GSHP systems over conventional space conditioning and water heating systems is primarily associated with drilling boreholes or excavating trenches, installing vertical or horizontal ground heat exchangers, and backfilling the excavations. This project investigates reducing the cost of horizontal closed-loop ground heat exchangers by installing them in the construction excavations, augmented when necessary with additional trenches. This approach applies only to new construction of residential and light commercial buildings or additions to such buildings. In the business-as-usual scenario, construction excavations are not used for the horizontal ground heat exchanger (HGHX); instead the HGHX is installed entirely in trenches dug specifically for that purpose. The potential cost savings comes from using the construction excavations for the installation of ground heat exchangers, thereby minimizing the need and expense of digging additional trenches. The term foundation heat exchanger (FHX

  5. Foundation Heat Exchanger Final Report: Demonstration, Measured Performance, and Validated Model and Design Tool

    SciTech Connect

    Hughes, Patrick; Im, Piljae

    2012-01-01

    Geothermal heat pumps, sometimes called ground-source heat pumps (GSHPs), have been proven capable of significantly reducing energy use and peak demand in buildings. Conventional equipment for controlling the temperature and humidity of a building, or supplying hot water and fresh outdoor air, must exchange energy (or heat) with the building's outdoor environment. Equipment using the ground as a heat source and heat sink consumes less non-renewable energy (electricity and fossil fuels) because the earth is cooler than outdoor air in summer and warmer in winter. The most important barrier to rapid growth of the GSHP industry is high first cost of GSHP systems to consumers. The most common GSHP system utilizes a closed-loop ground heat exchanger. This type of GSHP system can be used almost anywhere. There is reason to believe that reducing the cost of closed-loop systems is the strategy that would achieve the greatest energy savings with GSHP technology. The cost premium of closed-loop GSHP systems over conventional space conditioning and water heating systems is primarily associated with drilling boreholes or excavating trenches, installing vertical or horizontal ground heat exchangers, and backfilling the excavations. This project investigates reducing the cost of horizontal closed-loop ground heat exchangers by installing them in the construction excavations, augmented when necessary with additional trenches. This approach applies only to new construction of residential and light commercial buildings or additions to such buildings. In the business-as-usual scenario, construction excavations are not used for the horizontal ground heat exchanger (HGHX); instead the HGHX is installed entirely in trenches dug specifically for that purpose. The potential cost savings comes from using the construction excavations for the installation of ground heat exchangers, thereby minimizing the need and expense of digging additional trenches. The term foundation heat exchanger (FHX

  6. High performance alloy electroforming

    NASA Technical Reports Server (NTRS)

    Malone, G. A.; Winkelman, D. M.

    1989-01-01

    Electroformed copper and nickel are used in structural applications for advanced propellant combustion chambers. An improved process has been developed by Bell Aerospace Textron, Inc. wherein electroformed nickel-manganese alloy has demonstrated superior mechanical and thermal stability when compared to previously reported deposits from known nickel plating processes. Solution chemistry and parametric operating procedures are now established and material property data is established for deposition of thick, large complex shapes such as the Space Shuttle Main Engine. The critical operating variables are those governing the ratio of codeposited nickel and manganese. The deposition uniformity which in turn affects the manganese concentration distribution is affected by solution resistance and geometric effects as well as solution agitation. The manganese concentration in the deposit must be between 2000 and 3000 ppm for optimum physical properties to be realized. The study also includes data regarding deposition procedures for achieving excellent bond strength at an interface with copper, nickel-manganese or INCONEL 718. Applications for this electroformed material include fabrication of complex or re-entry shapes which would be difficult or impossible to form from high strength alloys such as INCONEL 718.

  7. High Poverty, High Performing Schools. IDRA Focus.

    ERIC Educational Resources Information Center

    IDRA Newsletter, 1997

    1997-01-01

    This theme issue includes four articles on high performance by poor Texas schools. In "Principal of National Blue Ribbon School Says High Poverty Schools Can Excel" (interview with Robert Zarate by Christie L. Goodman), the principal of Mary Hull Elementary School (San Antonio, Texas) describes how the high-poverty, high-minority school…

  8. Study on heat transfer of heat exchangers in the Stirling engine - Performance of heat exchangers in the test Stirling engine

    NASA Astrophysics Data System (ADS)

    Kanzaka, Mitsuo; Iwabuchi, Makio

    1992-11-01

    The heat transfer performance of the actual heat exchangers obtained from the experimental results of the test Stirling engine is presented. The heater for the test engine has 120 heat transfer tubes that consist of a bare-tube part and a fin-tube part. These tubes are located around the combustion chamber and heated by the combustion gas. The cooler is the shell-and-tube-type heat exchanger and is chilled by water. It is shown that the experimental results of heat transfer performance of the heater and cooler of the test Stirling engine are in good agreement with the results calculated by the correlation proposed in our previous heat transfer study under the periodically reversing flow condition. Our correlation is thus confirmed to be applicable to the evaluation of the heat transfer coefficient and the thermal design of the heat exchangers in the Stirling engine.

  9. Supercritical heat exchanger field test (SHEFT), I. Field performance data on shell-and-tube heat exchangers in geothermal service

    SciTech Connect

    Silvester, L.F.; Beaulaurier, L.O.; Mirk, K.F.; Fulton, R.L.

    1981-06-01

    Field performance data on shell-and-tube heat exchangers in geothermal service are presented. The test data were taken for geothermal brine on the tube side and hydrocarbon on the shell side in counterflow for six primary heat exchangers, and for hydrocarbon on the shell side and cooling water on the tube side for the condenser. Test data were for heating isobutane, 1 90/10 isobutane/isopentane mixture, and a 80/20 isobutane/isopentane mixture at supercritical conditions in the vicinity of their critical pressure and temperature, and for condensing the same fluids. The test data were used in a preliminary data analysis to determine the reported heat exchanger performance parameters.

  10. High-performance liquid chromatography - Ultraviolet method for the determination of total specific migration of nine ultraviolet absorbers in food simulants based on 1,1,3,3-Tetramethylguanidine and organic phase anion exchange solid phase extraction to remove glyceride.

    PubMed

    Wang, Jianling; Xiao, Xiaofeng; Chen, Tong; Liu, Tingfei; Tao, Huaming; He, Jun

    2016-06-17

    The glyceride in oil food simulant usually causes serious interferences to target analytes and leads to failure of the normal function of the RP-HPLC column. In this work, a convenient HPLC-UV method for the determination of the total specific migration of nine ultraviolet (UV) absorbers in food simulants was developed based on 1,1,3,3-tetramethylguanidine (TMG) and organic phase anion exchange (OPAE) SPE to efficiently remove glyceride in olive oil simulant. In contrast to the normal ion exchange carried out in an aqueous solution or aqueous phase environment, the OPAE SPE was performed in the organic phase environments, and the time-consuming and challenging extraction of the nine UV absorbers from vegetable oil with aqueous solution could be readily omitted. The method was proved to have good linearity (r≥0.99992), precision (intra-day RSD≤3.3%), and accuracy(91.0%≤recoveries≤107%); furthermore, the lower limit of quantifications (0.05-0.2mg/kg) in five types of food simulants(10% ethanol, 3% acetic acid, 20% ethanol, 50% ethanol and olive oil) was observed. The method was found to be well suited for quantitative determination of the total specific migration of the nine UV absorbers both in aqueous and vegetable oil simulant according to Commission Regulation (EU) No. 10/2011. Migration levels of the nine UV absorbers were determined in 31 plastic samples, and UV-24, UV-531, HHBP and UV-326 were frequently detected, especially in olive oil simulant for UV-326 in PE samples. In addition, the OPAE SPE procedure was also been applied to efficiently enrich or purify seven antioxidants in olive oil simulant. Results indicate that this procedure will have more extensive applications in the enriching or purification of the extremely weak acidic compounds with phenol hydroxyl group that are relatively stable in TMG n-hexane solution and that can be barely extracted from vegetable oil. PMID:27189432

  11. High Performance Fortran: An overview

    SciTech Connect

    Zosel, M.E.

    1992-12-23

    The purpose of this paper is to give an overview of the work of the High Performance Fortran Forum (HPFF). This group of industry, academic, and user representatives has been meeting to define a set of extensions for Fortran dedicated to the special problems posed by a very high performance computers, especially the new generation of parallel computers. The paper describes the HPFF effort and its goals and gives a brief description of the functionality of High Performance Fortran (HPF).

  12. Polybenzimidazole-crosslinked poly(vinylbenzyl chloride) with quaternary 1,4-diazabicyclo (2.2.2) octane groups as high-performance anion exchange membrane for fuel cells

    NASA Astrophysics Data System (ADS)

    Lu, Wangting; Zhang, Geng; Li, Jin; Hao, Jinkai; Wei, Feng; Li, Wenhui; Zhang, Jiying; Shao, Zhi-Gang; Yi, Baolian

    2015-11-01

    Development of anion exchange membrane (AEM) with high conductivity, good dimensional stability, desirable toughness and long life-time simultaneously is still a challenge for the practical application of AEM fuel cells. Herein, a novel AEM (denoted as PBI-c-PVBC/OH) is fabricated by applying polybenzimidazole (PBI) and 1,4-diazabicyclo (2.2.2) octane (DABCO) as the macromolecular crosslinker and quaternizing reagent for poly(vinylbenzyl chloride) (PVBC), respectively. With the aid of crosslinking by PBI, PBI-c-PVBC/OH exhibits good flexibility and strength both in dry and water-saturated state. Moreover, high hydroxide conductivity (>25 mS cm-1 at room temperature) and low swelling ratio (∼13%) is obtained, especially the swelling ratio nearly does not increase with temperature. The membrane is also advanced for the superior chemical stability in alkaline environment due to the stable polymer backbone and ionic conductive group (only one nitrogen atom in a DABCO molecule is quaternized). Furthermore, a peak power density of 230 mW cm-2 at 50 °C is obtained on the H2/O2 fuel cell using PBI-c-PVBC/OH, and the membrane presents high durability both in the constant current and continuous open circuit voltage testing. Therefore, it is considered that the PBI crosslinking together with DABCO quaternization can be regarded as a promising strategy in the development of AEM for fuel cells.

  13. Thermal Performance of a Dual-Channel, Helium-Cooled, Tungsten Heat Exchanger

    SciTech Connect

    YOUCHISON,DENNIS L.; NORTH,MART T.

    2000-11-22

    Helium-cooled, refractory heat exchangers are now under consideration for first wall and divertor applications. These refractory devices take advantage of high temperature operation with large delta-Ts to effectively handle high heat fluxes. The high temperature helium can then be used in a gas turbine for high-efficiency power conversion. Over the last five years, heat removal with helium was shown to increase dramatically by using porous metal to provide a very large effective surface area for heat transfer in a small volume. Last year, the thermal performance of a bare-copper, dual-channel, helium-cooled, porous metal divertor mock-up was evaluated on the 30 kW Electron Beam Test System at Sandia National Laboratories. The module survived a maximum absorbed heat flux of 34.6 MW/m{sup 2} and reached a maximum surface temperature of 593 C for uniform power loading of 3 kW absorbed on a 2-cm{sup 2} area. An impressive 10 kW of power was absorbed on an area of 24 cm{sup 2}. Recently, a similar dual-module, helium-cooled heat exchanger made almost entirely of tungsten was designed and fabricated by Thermacore, Inc. and tested at Sandia. A complete flow test of each channel was performed to determine the actual pressure drop characteristics. Each channel was equipped with delta-P transducers and platinum RTDs for independent calorimetry. One mass flow meter monitored the total flow to the heat exchanger, while a second monitored flow in only one of the channels. The thermal response of each tungsten module was obtained for heat fluxes in excess of 5 MW/m{sup 2} using 50 C helium at 4 MPa. Fatigue cycles were also performed to assess the fracture toughness of the tungsten modules. A description of the module design and new results on flow instabilities are also presented.

  14. NGNP/HTE full-power operation at reduced high-temperature heat exchanger temperatures.

    SciTech Connect

    VIlim, R.; Nuclear Engineering Division

    2009-03-12

    Operation of the Next Generation Nuclear Plant (NGNP) with reduced reactor outlet temperature at full power was investigated for the High Temperature Electrolysis (HTE) hydrogen-production application. The foremost challenge for operation at design temperature is achieving an acceptably long service life for heat exchangers. In both the Intermediate Heat Exchanger (IHX) and the Process Heat Exchanger (PHX) (referred to collectively as high temperature heat exchangers) a pressure differential of several MPa exists with temperatures at or above 850 C. Thermal creep of the heat exchanger channel wall may severely limit heat exchanger life depending on the alloy selected. This report investigates plant performance with IHX temperatures reduced by lowering reactor outlet temperature. The objective is to lower the temperature in heat transfer channels to the point where existing materials can meet the 40 year lifetime needed for this component. A conservative estimate for this temperature is believed to be about 700 C. The reactor outlet temperature was reduced from 850 C to 700 C while maintaining reactor power at 600 MWt and high pressure compressor outlet at 7 MPa. We included a previously reported design option for reducing temperature at the PHX. Heat exchanger lengths were adjusted to reflect the change in performance resulting from coolant property changes and from resizing related to operating-point change. Turbomachine parameters were also optimized for the new operating condition. An integrated optimization of the complete system including heat transfer equipment was not performed. It is estimated, however, that by performing a pinch analysis the combined plant efficiency can be increased from 35.5 percent obtained in this report to a value between 38.5 and 40.1 percent. Then after normalizing for a more than three percent decrease in commodities inventory compared to the reference plant, the commodities-normalized efficiency lies between 40.0 and 41.3. This

  15. High Performance Thin Layer Chromatography.

    ERIC Educational Resources Information Center

    Costanzo, Samuel J.

    1984-01-01

    Clarifies where in the scheme of modern chromatography high performance thin layer chromatography (TLC) fits and why in some situations it is a viable alternative to gas and high performance liquid chromatography. New TLC plates, sample applications, plate development, and instrumental techniques are considered. (JN)

  16. Erbium doping of lithium niobate by the ion exchange process for high-gain optical amplifiers

    NASA Astrophysics Data System (ADS)

    Caccavale, Frederico; Fedorov, Vyacheslav A.; Korkishko, Yuri N.; Morozova, Tamara V.; Sada, Cinzia; Segato, Francesco

    2000-04-01

    The erbium-lithium ion exchange is presented as a method for the erbium local doping of lithium niobate crystals. Ion exchange process is performed immersing the LiNbO3 substrates in a liquid melt, containing erbium ions; due to their high mobility, the lithium ions migrate from the crystal to the melt, and are replaced by erbium ions. A systematic analysis of the doping process is performed, and the influence of the process parameters is investigated: exchange time and temperature, crystal cut direction, composition and chemical reactivity of the Er ions liquid source. By structural (X-Ray Diffraction and Rutherford Backscattering Spectrometry), compositional (Secondary Ion Mass Spectrometry) and spectroscopic techniques (optical spectroscopy and micro-luminescence), the formation of lithium deficient phases and the incorporation of the Er ions into the LiNbO3 matrix is studied.

  17. Highly Water Resistant Anion Exchange Membrane for Fuel Cells.

    PubMed

    Yang, Zhengjin; Hou, Jianqiu; Wang, Xinyu; Wu, Liang; Xu, Tongwen

    2015-07-01

    For anion exchange membranes (AEMs), achieving efficient hydroxide conductivity without excessive hydrophilicity presents a challenge. Hence, new strategies for constructing mechanically strengthened and hydroxide conductive (especially at controlled humidity) membranes are critical for developing better AEMs. Macromolecular modification involving ylide chemistry (Wittig reaction) for the fabrication of novel AEMs with an interpenetrating polymer network structure is reported. The macromolecular modification is cost effective, facile, and based on a one-pot synthesis. AEM water uptake is reduced to 3.6 wt% and a high hydroxide conductivity (69.7 mS cm(-1) , 90 °C) is achieved simultaneously. More importantly, the membrane exhibits similar tensile strength (>35 MPa) and comparable flexibility in both dry and wet states. These AEMs could find further applications within anion exchange membrane fuel cells with low humidity or photoelectric assemblies. PMID:25962480

  18. Non-destructive evaluation of membrane lung gas exchange performance.

    PubMed

    Tallman, R D; Guardia, Z A; Gruber, M A

    1996-12-01

    This paper describes a method of evaluating the gas exchange effectiveness of hollow fiber oxygenators utilizing gas on both sides of the membrane. The goal of the study was to develop an evaluation technique which was accurate, reliable, and did not harm or contaminate a new, sterile oxygenator. Three pediatric oxygenators were tested and compared: the Medtronic Minimax Plus, the Terumo Capiox 320, and the Sorin Masterflo 34 (all with rated blood flows of 2-2.5 L/min). Gas entering the "blood" side was a mixture of CO2, O2, and N2 in a mixture matching typical venous blood partial pressures. The "blood" flows used were 0.5, 1, 1.5, or 2 L/min. Gas entering the gas port had an FiO2 of 0.4 flowing at 0.5, 1, 1.5, 2, 2.5, 3, or 3.5 L/min. Fractional contents of CO2 and O2 at all inlets and outlets were determined using a gas analyzer and converted to partial pressures. Efficacy indices and gas transfer rates were calculated and compared. Of the devices studied, the Masterflo 34 had the highest gas transport rates and effectiveness followed by the Minimax-Plus and the Capiox 320. Reversing the direction of the flow through the "blood" phase of the Minimax-Plus greatly changed its gas exchange effectiveness. The techniques described in this study should allow for a more uniform and consistent evaluation of gas exchange by membrane lungs which can be made inexpensively and relatively quickly. In addition, these methods should allow manufactures to evaluate gas exchange effectiveness and transfer rates of individual units during production as well as reduce the complexity involved when evaluating newly developed oxygenators. PMID:10164050

  19. Experimental investigation of a reticulated porous alumina heat exchanger for high temperature gas heat recovery

    SciTech Connect

    Banerjee, A; Chandran, RB; Davidson, JH

    2015-01-22

    The present study presents an experimental study of a prototype counter-flow heat exchanger designed to recover sensible heat from inert and reactive gases flowing through a high temperature solar reactor for splitting CO2. The tube-in-tube heat exchanger is comprised of two concentric alumina tubes, each filled with reticulated porous alumina with a nominal porosity of 80% and pore density of 5 pores per inch (ppi). The RPC provides high heat transfer surface area per unit volume (917 m(-1)) with low pressure drop. Measurements include the permeability, inertial coefficient, overall heat transfer coefficient, effectiveness and pressure drop. For laminar flow and an inlet gas temperature of 1240 K, the overall heat transfer coefficients are 36-41 W m(-2) K-1. The measured performance is in good agreement with a prior CFD model of the heat exchanger. (C) 2014 Elsevier Ltd. All rights reserved.

  20. Thermal performance of plate-fin heat exchanger using passive techniques: vortex-generator and nanofluid

    NASA Astrophysics Data System (ADS)

    Khoshvaght-Aliabadi, Morteza

    2016-04-01

    This experimental study investigates the effects of vortex-generator (VG) and Cu/water nanofluid flow on performance of plate-fin heat exchangers. The Cu/water nanofluids are produced by using a one-step method, namely electro-exploded wire technique, with four nanoparticles weight fractions (i.e. 0.1, 0.2, 0.3, and 0.4 %). Required properties of nanofluids are systematically measured, and empirical correlations are developed. A highly precise test loop is fabricated to obtain accurate results of the heat transfer and pressure drop characteristics. Experiments are conducted for nanofluids flow inside the plain and VG channels. Based on the experimental results, utilizing the VG channel instead of the plain channel enhances the heat transfer rate, remarkably. Also, the results show that the VG channel is more effective than the nanofluid on the performance of plate-fin heat exchangers. It is observed that the combination of the two heat transfer enhancement techniques has a noticeably high thermal-hydraulic performance, about 1.67. Finally, correlations are developed to predict Nusselt number and friction factor of nanofluids flow inside the VG channel.

  1. Evaluation of high-performance computing software

    SciTech Connect

    Browne, S.; Dongarra, J.; Rowan, T.

    1996-12-31

    The absence of unbiased and up to date comparative evaluations of high-performance computing software complicates a user`s search for the appropriate software package. The National HPCC Software Exchange (NHSE) is attacking this problem using an approach that includes independent evaluations of software, incorporation of author and user feedback into the evaluations, and Web access to the evaluations. We are applying this approach to the Parallel Tools Library (PTLIB), a new software repository for parallel systems software and tools, and HPC-Netlib, a high performance branch of the Netlib mathematical software repository. Updating the evaluations with feed-back and making it available via the Web helps ensure accuracy and timeliness, and using independent reviewers produces unbiased comparative evaluations difficult to find elsewhere.

  2. High Performance Networks for High Impact Science

    SciTech Connect

    Scott, Mary A.; Bair, Raymond A.

    2003-02-13

    This workshop was the first major activity in developing a strategic plan for high-performance networking in the Office of Science. Held August 13 through 15, 2002, it brought together a selection of end users, especially representing the emerging, high-visibility initiatives, and network visionaries to identify opportunities and begin defining the path forward.

  3. Cation exchange pretreatment studies for high recovery - Yuma desalting plant

    SciTech Connect

    Kaakinen, J.W.; Laverty, P.E.

    1983-10-01

    The main purpose of the High Recovery Test Program was to obtain feasibility design data for cation exchange softening to allow a greater fractional recovery of desalted product water at the YDP(Yuma Desalting Plant). Compared to the original YDP design with 70-percent desalting recovery, additional removal of calcium in the desalting feed would allow recoveries over 90 percent. Pilot plant equipment to test this process was operated at the YDTF(Yuma Desalting Test Facility) and consisted of an IX unit and an electrodialyzer to supply reject-brine regenerant for the IX experiments. Gypsum scale buildup in the resin bed could be avoided by regeneration with a high upward flow rate causing a fluidized bed. Reuse of regenerant was also beneficial. Results show that the ion exchange high recovery pretreatment process is highly feasible, and that it is technically possible to achieve high recovery in the YDP. Numerous recommendations for a plant design are given and future studies are noted.

  4. A review on the performance and modelling of proton exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Boucetta, A.; Ghodbane, H.; Ayad, M. Y.; Bahri, M.

    2016-07-01

    Proton Exchange Membrane Fuel Cells (PEMFC), are energy efficient and environmentally friendly alternative to conventional energy conversion for various applications in stationary power plants, portable power device and transportation. PEM fuel cells provide low operating temperature and high-energy efficiency with near zero emission. A PEM fuel cell is a multiple distinct parts device and a series of mass, energy, transport through gas channels, electric current transport through membrane electrode assembly and electrochemical reactions at the triple-phase boundaries. These processes play a decisive role in determining the performance of the Fuel cell, so that studies on the phenomena of gas flows and the performance modelling are made deeply. This paper gives a comprehensive overview of the state of the art on the Study of the phenomena of gas flow and performance modelling of PEMFC.

  5. Partition Coefficients of Selected Compounds Using Ion Exchange Separation of Cesium From High Level Waste

    SciTech Connect

    Toth, James J.; Blanchard, David L.; Arm, Stuart T.; Urie, Michael W.

    2004-04-24

    The removal of cesium radioisotope (137Cs) from the High Level Waste stored in underground storage tanks at the Hanford site is a formidable chemical separations challenge for the Waste Treatment Plant. An eluatable organic-based ion exchange resin was selected as the baseline technology (1). The baseline technology design employs a proprietary macrocyclic weak-acid ion exchange resin to adsorb the cesium (137Cs) during the process loading cycle in a fixed bed column design. Following loading, the cesium is eluted from the resin using a nitric acid eluant. Previous work provided limited understanding of the performance of the resin, processed with actual wastes, and under multiple load and elute conditions, which are required for the ion exchange technology to be underpinned sufficiently for resolution of all process-related design issues before flowsheet and construction drawings can be released. By performing multiple ion exchange column tests with waste feeds, and measuring the chemical and radionuclide compositions of the waste feeds, column effluents and column eluants, ion exchange stream composition information can be provided for supporting resolution of selected design issues.

  6. A computer program for condensing heat exchanger performance in the presence of noncondensable gases

    NASA Technical Reports Server (NTRS)

    Yendler, Boris

    1994-01-01

    A computer model has been developed which evaluates the performance of a heat exchanger. This model is general enough to be used to evaluate many heat exchanger geometries and a number of different operating conditions. The film approach is used to describe condensation in the presence of noncondensables. The model is also easily expanded to include other effects like fog formation or suction.

  7. ZEOLITE PERFORMANCE AS AN ANION EXCHANGER FOR ARSENIC SEQUESTRATION IN WATER

    EPA Science Inventory

    Zeolites are well known for their use in ion exchange and acid catalysis reactions. The use of zeolites in anion or ligand exchange reactions is less studied. The NH4+ form of zeolite Y (NY6, Faujasite) has been tested in this work to evaluate its performance for arsenic removal...

  8. A dynamical structure of high frequency currency exchange market

    NASA Astrophysics Data System (ADS)

    Sazuka, Naoya; Ohira, Toru; Marumo, Kouhei; Shimizu, Tokiko; Takayasu, Misako; Takayasu, Hideki

    2003-06-01

    We analyze tick-by-tick data, the most high frequency data available, of yen-dollar currency exchange rates. We show that a dynamical structure can be observed in binarized data indicating the direction of up and down movement of prices, which is not apparently seen from the price change itself. This result is consistent with our previous study that there exists a conditional probabilistic structure in binarized data. The dynamical and probabilistic structure which we found could indicate that dealers’ decision making is based on a binary strategy, even if they are unconscious of this fact.

  9. High performance flexible heat pipes

    NASA Technical Reports Server (NTRS)

    Shaubach, R. M.; Gernert, N. J.

    1985-01-01

    A Phase I SBIR NASA program for developing and demonstrating high-performance flexible heat pipes for use in the thermal management of spacecraft is examined. The program combines several technologies such as flexible screen arteries and high-performance circumferential distribution wicks within an envelope which is flexible in the adiabatic heat transport zone. The first six months of work during which the Phase I contract goal were met, are described. Consideration is given to the heat-pipe performance requirements. A preliminary evaluation shows that the power requirement for Phase II of the program is 30.5 kilowatt meters at an operating temperature from 0 to 100 C.

  10. Welding of dissimilar alloys for high temperature heat exchangers for SOFC

    SciTech Connect

    Wilson, R.D.; Hatem, J.; Dogan, O.N.; King, P.E.

    2006-10-01

    Reduction in the cost of balance of plant applications is one of the top priority focus areas for the successful implementation of solid oxide fuel cell technology. High temperature heat exchangers are employed to heat cathode air utilizing either hot gases coming from the anode side of the stack or other hot gases generated by external processes. In order to reduce the cost of heat exchangers, it may be necessary to apply several different materials, each in a different temperature zone, for the construction of the heat exchanger. This technique would require the joining of dissimilar materials in the construction. In this work, welding of commercial candidate dissimilar materials is explored. Filler materials were identified using equilibrium phase diagrams and thermodynamic simulation software. Autogenous welding was performed and the welding defects were characterized. Finally, experimental weld microstructures were compared to phases predicted by the simulations.

  11. Cyclic high temperature heat storage using borehole heat exchangers

    NASA Astrophysics Data System (ADS)

    Boockmeyer, Anke; Delfs, Jens-Olaf; Bauer, Sebastian

    2016-04-01

    The transition of the German energy supply towards mainly renewable energy sources like wind or solar power, termed "Energiewende", makes energy storage a requirement in order to compensate their fluctuating production and to ensure a reliable energy and power supply. One option is to store heat in the subsurface using borehole heat exchangers (BHEs). Efficiency of thermal storage is increasing with increasing temperatures, as heat at high temperatures is more easily injected and extracted than at temperatures at ambient levels. This work aims at quantifying achievable storage capacities, storage cycle times, injection and extraction rates as well as thermal and hydraulic effects induced in the subsurface for a BHE storage site in the shallow subsurface. To achieve these aims, simulation of these highly dynamic storage sites is performed. A detailed, high-resolution numerical simulation model was developed, that accounts for all BHE components in geometrical detail and incorporates the governing processes. This model was verified using high quality experimental data and is shown to achieve accurate simulation results with excellent fit to the available experimental data, but also leads to large computational times due to the large numerical meshes required for discretizing the highly transient effects. An approximate numerical model for each type of BHE (single U, double U and coaxial) that reduces the number of elements and the simulation time significantly was therefore developed for use in larger scale simulations. The approximate numerical model still includes all BHE components and represents the temporal and spatial temperature distribution with a deviation of less than 2% from the fully discretized model. Simulation times are reduced by a factor of ~10 for single U-tube BHEs, ~20 for double U-tube BHEs and ~150 for coaxial BHEs. This model is then used to investigate achievable storage capacity, injection and extraction rates as well as induced effects for

  12. Performance of OTEC Heat Exchanger Materials in Tropical Seawaters

    NASA Astrophysics Data System (ADS)

    Larsen-Basse, Jorn

    1985-03-01

    The corrosion of several aluminum alloys in flowing Hawaiian surface seawater and water from 600 m depth for exposure periods up to three years has been studied. The alloys tested in cold water were Alclad (7072) 3003 and 3004; and bare 3004 and 5052). All show some pitting. Pit growth is slow, and pits do not penetrate the cladding. In the warm water, only uniform corrosion has been found. All alloys corrode at the same, low rate of˜3 μm/year after an initial short period of more rapid corrosion. This behavior is closely linked to the formation of a protective inorganic scale film on the surface. It consists of precipitated scale minerals from the seawater and aluminum corrosion products. The results indicate that OTEC evaporator heat exchangers constructed of aluminum alloys should have acceptable service lives.

  13. High performance dielectric materials development

    NASA Technical Reports Server (NTRS)

    Piche, Joe; Kirchner, Ted; Jayaraj, K.

    1994-01-01

    The mission of polymer composites materials technology is to develop materials and processing technology to meet DoD and commercial needs. The following are outlined in this presentation: high performance capacitors, high temperature aerospace insulation, rationale for choosing Foster-Miller (the reporting industry), the approach to the development and evaluation of high temperature insulation materials, and the requirements/evaluation parameters. Supporting tables and diagrams are included.

  14. Advanced solidification system using high performance cement

    SciTech Connect

    Kikuchi, Makoto; Matsuda, Masami; Nishi, Takashi; Tsuchiya, Hiroyuki; Izumida, Tatsuo

    1995-12-31

    Advanced cement solidification is proposed for the solidification of radioactive waste such as spent ion exchange resin, incineration ash and liquid waste. A new, high performance cement has been developed to raise volume reduction efficiency and lower radioactivity release into the environment. It consists of slag cement, reinforcing fiber, natural zeolite and lithium nitrate (LiNO{sub 3}). The fiber allows waste loading to be increased from 20 to 55kg-dry resin/200L. The zeolite, whose main constituent is clinoptilolite, reduces cesium leachability from the waste form to about 1/10. Lithium nitrate prevents alkaline corrosion of the aluminum, contained in ash, and reduces hydrogen gas generation. Laboratory and full-scale pilot plant experiments were performed to evaluate properties of the waste form, using simulated wastes. Emphasis was laid on improvement of solidification of spent resin and ash.

  15. Plate heat exchanger performance in a nuclear safety-related service water application

    SciTech Connect

    Bowman, C.F.; Craig, E.F.

    1995-12-31

    In the mid-1980`s the Tennessee Valley Authority installed plate heat exchangers in the safety-related service water system at the Sequoyah Nuclear Plant. These heat exchangers are compact, they can be assembled in place, they require less flow than more conventional heat exchangers, and they are easily cleaned. However, equations to predict thermal performance are not readily available in the open literature. An analytical model was developed to predict performance of the heat exchangers at off-design conditions and to trend thermal performance. Periodic surveillance tests have been performed and the fouling resistance has been calculated based on these tests and the analytical model. Biological fouling of the plates on the raw water side was determined to be greater than expected due to inadequate biocide treatment of the system.

  16. The performance of ammonium exchanged zeolite for the biodegradation of petroleum hydrocarbons migrating in soil water.

    PubMed

    Freidman, Benjamin L; Gras, Sally L; Snape, Ian; Stevens, Geoff W; Mumford, Kathryn A

    2016-08-01

    Nitrogen deficiency has been identified as the main inhibiting factor for biodegradation of petroleum hydrocarbons in low nutrient environments. This study examines the performance of ammonium exchanged zeolite to enhance biodegradation of petroleum hydrocarbons migrating in soil water within laboratory scale flow cells. Biofilm formation and biodegradation were accelerated by the exchange of cations in soil water with ammonium in the pores of the exchanged zeolite when compared with natural zeolite flow cells. These results have implications for sequenced permeable reactive barrier design and the longevity of media performance within such barriers at petroleum hydrocarbon contaminated sites deficient in essential soil nutrients. PMID:27132074

  17. INL High Performance Building Strategy

    SciTech Connect

    Jennifer D. Morton

    2010-02-01

    High performance buildings, also known as sustainable buildings and green buildings, are resource efficient structures that minimize the impact on the environment by using less energy and water, reduce solid waste and pollutants, and limit the depletion of natural resources while also providing a thermally and visually comfortable working environment that increases productivity for building occupants. As Idaho National Laboratory (INL) becomes the nation’s premier nuclear energy research laboratory, the physical infrastructure will be established to help accomplish this mission. This infrastructure, particularly the buildings, should incorporate high performance sustainable design features in order to be environmentally responsible and reflect an image of progressiveness and innovation to the public and prospective employees. Additionally, INL is a large consumer of energy that contributes to both carbon emissions and resource inefficiency. In the current climate of rising energy prices and political pressure for carbon reduction, this guide will help new construction project teams to design facilities that are sustainable and reduce energy costs, thereby reducing carbon emissions. With these concerns in mind, the recommendations described in the INL High Performance Building Strategy (previously called the INL Green Building Strategy) are intended to form the INL foundation for high performance building standards. This revised strategy incorporates the latest federal and DOE orders (Executive Order [EO] 13514, “Federal Leadership in Environmental, Energy, and Economic Performance” [2009], EO 13423, “Strengthening Federal Environmental, Energy, and Transportation Management” [2007], and DOE Order 430.2B, “Departmental Energy, Renewable Energy, and Transportation Management” [2008]), the latest guidelines, trends, and observations in high performance building construction, and the latest changes to the Leadership in Energy and Environmental Design

  18. High Performance Photovoltaic Project Overview

    SciTech Connect

    Symko-Davies, M.; McConnell, R.

    2005-01-01

    The High-Performance Photovoltaic (HiPerf PV) Project was initiated by the U.S. Department of Energy to substantially increase the viability of photovoltaics (PV) for cost-competitive applications so that PV can contribute significantly to our energy supply and environment in the 21st century. To accomplish this, the National Center for Photovoltaics (NCPV) directs in-house and subcontracted research in high-performance polycrystalline thin-film and multijunction concentrator devices. In this paper, we describe the recent research accomplishments in the in-house directed efforts and the research efforts under way in the subcontracted area.

  19. High-Performance Thermoelectric Semiconductors

    NASA Technical Reports Server (NTRS)

    Fleurial, Jean-Pierre; Caillat, Thierry; Borshchevsky, Alexander

    1994-01-01

    Figures of merit almost double current state-of-art thermoelectric materials. IrSb3 is semiconductor found to exhibit exceptional thermoelectric properties. CoSb3 and RhSb3 have same skutterudite crystallographic structure as IrSb3, and exhibit exceptional transport properties expected to contribute to high thermoelectric performance. These three compounds form solid solutions. Combination of properties offers potential for development of new high-performance thermoelectric materials for more efficient thermoelectric power generators, coolers, and detectors.

  20. High-performance membrane chromatography.

    PubMed

    Belenkii, B G; Malt'sev, V G

    1995-02-01

    In gradient chromatography for proteins migrating along the chromatographic column, the critical distance X0 has been shown to exist at which the separation of zones is at a maximum and band spreading is at a minimum. With steep gradients and small elution velocity, the column length may be reduced to the level of membrane thickness--about one millimeter. The peculiarities of this novel separation method for proteins, high-performance membrane chromatography (HPMC), are discussed and stepwise elution is shown to be especially effective. HPMC combines the advantages of membrane technology and high-performance liquid chromatography, and avoids their drawbacks. PMID:7727132

  1. Improved Electrodes for High Temperature Proton Exchange Membrane Fuel Cells using Carbon Nanospheres.

    PubMed

    Zamora, Héctor; Plaza, Jorge; Cañizares, Pablo; Lobato, Justo; Rodrigo, Manuel A

    2016-05-23

    This work evaluates the use of carbon nanospheres (CNS) in microporous layers (MPL) of high temperature proton exchange membrane fuel cell (HT-PEMFC) electrodes and compares the characteristics and performance with those obtained using conventional MPL based on carbon black. XRD, hydrophobicity, Brunauer-Emmett-Teller theory, and gas permeability of MPL prepared with CNS were the parameters evaluated. In addition, a short life test in a fuel cell was carried out to evaluate performance under accelerated stress conditions. The results demonstrate that CNS is a promising alternative to traditional carbonaceous materials because of its high electrochemical stability and good electrical conductivity, suitable to be used in this technology. PMID:27076055

  2. Enhanced performance of anion exchange membranes via crosslinking of ion cluster regions for fuel cells

    NASA Astrophysics Data System (ADS)

    Lai, Ao Nan; Guo, Dong; Lin, Chen Xiao; Zhang, Qiu Gen; Zhu, Ai Mei; Ye, Mei Ling; Liu, Qing Lin

    2016-09-01

    Development of anion exchange membranes (AEMs) with high hydroxide conductivity, good dimensional and alkaline stabilities is still a challenge for the practical application of AEM fuel cells. In this study, we report a new strategy to prepare high-performance AEMs with crosslinked ionic regions. A series of phenolphthalein-containing poly(arylene ether sulfone)s crosslinked AEMs was synthesized by grafting ion groups selectively and densely on the phenolphthalein units to form ion clusters that are further crosslinked to generate the hydrophilic ionic regions. The crosslinking reaction not only improved the dimensional stability of the AEMs, but also increased the aggregation of the ion clusters leading to the formation of hydrophilic/hydrophobic phase-separated morphology and ion-conducting channels. As a result, enhancements in both ion conductivity and dimensional stability can be achieved. The crosslinked AEMs showed high hydroxide conductivities in the range of 52.2-143.4 mS cm-1 from 30 to 80 °C and a superb ratio of relative conductivity to relative swelling at 80 °C. Furthermore, the crosslinked AEMs also exhibited good mechanical properties, thermal and alkaline stabilities and desirable single cell performance. This work presents a promising strategy for the synthesis of high-performance AEMs for fuel cells.

  3. Hydrogel-Stabilized Droplet Bilayers for High Speed Solution Exchange

    PubMed Central

    Acharya, Shiv A.; Portman, Alexander; Salazar, Carl S.; Schmidt, Jacob J.

    2013-01-01

    Many applications utilizing artificial lipid bilayers require the ability to exchange the bilayer's solution environment. However, because of the instability of the bilayer, the rate of solution exchange is limited, which significantly hinders the measurement rate and throughput. We have developed an artificial bilayer system that can withstand high flow speeds, up to 2.1 m/s, by supporting the bilayer with a hydrogel. We demonstrated the ability to measure during flow by measuring the conductance of gramicidin-A channels while switching between solutions of two different compositions, recording a time to measure 90% change in current of approximately 2.7 seconds at a flow rate of 0.1 m/s. We also demonstrated a potential application of this system by measuring the conductance modulation of the rat TRPM8 ion channel by an agonist and antagonist at varying concentrations, obtaining 7-point IC50 and EC50 values in approximately 7 minutes and 4-point values within 4 minutes. PMID:24190577

  4. Hydrogel-Stabilized Droplet Bilayers for High Speed Solution Exchange

    NASA Astrophysics Data System (ADS)

    Acharya, Shiv A.; Portman, Alexander; Salazar, Carl S.; Schmidt, Jacob J.

    2013-11-01

    Many applications utilizing artificial lipid bilayers require the ability to exchange the bilayer's solution environment. However, because of the instability of the bilayer, the rate of solution exchange is limited, which significantly hinders the measurement rate and throughput. We have developed an artificial bilayer system that can withstand high flow speeds, up to 2.1 m/s, by supporting the bilayer with a hydrogel. We demonstrated the ability to measure during flow by measuring the conductance of gramicidin-A channels while switching between solutions of two different compositions, recording a time to measure 90% change in current of approximately 2.7 seconds at a flow rate of 0.1 m/s. We also demonstrated a potential application of this system by measuring the conductance modulation of the rat TRPM8 ion channel by an agonist and antagonist at varying concentrations, obtaining 7-point IC50 and EC50 values in approximately 7 minutes and 4-point values within 4 minutes.

  5. Performance of multiple mini-tube heat exchangers as an internal heat exchanger of a vapor-injection cycle heat pump

    NASA Astrophysics Data System (ADS)

    Jang, Jin Yong; Jeong, Ji Hwan

    2016-04-01

    A multiple mini-tube (MMT) heat exchanger was considered as an internal heat exchanger of vapor-injection cycle heat pump. Heat transfer and pressure drop in multiple mini-tube heat exchangers were numerically and experimentally investigated. Results show that the best performance of the MMT heat exchanger can be obtained when the intermediate-pressure two-phase refrigerant is supplied to the shell-side and this refrigerant reaches a saturated vapor state at the exit of the heat exchanger.

  6. Exchange across the shelf break at high southern latitudes

    NASA Astrophysics Data System (ADS)

    Klinck, J. M.; Dinniman, M. S.

    2010-05-01

    Exchange of water across the Antarctic shelf break has considerable scientific and societal importance due to its effects on circulation and biology of the region, conversion of water masses as part of the global overturning circulation and basal melt of glacial ice and the consequent effect on sea level rise. The focus in this paper is the onshore transport of warm, oceanic Circumpolar Deep Water (CDW); export of dense water from these shelves is equally important, but has been the focus of other recent papers and will not be considered here. A variety of physical mechanisms are described which could play a role in this onshore flux. The relative importance of some processes are evaluated by simple calculations. A numerical model for the Ross Sea continental shelf is used as an example of a more comprehensive evaluation of the details of cross-shelf break exchange. In order for an ocean circulation model to simulate these processes at high southern latitudes, it needs to have high spatial resolution, realistic geometry and bathymetry. Grid spacing smaller than the first baroclinic radius of deformation (a few km) is required to adequately represent the circulation. Because of flow-topography interactions, bathymetry needs to be represented at these same small scales. Atmospheric conditions used to force these circulation models also need to be known at a similar small spatial resolution (a few km) in order to represent orographically controlled winds (coastal jets) and katabatic winds. Significantly, time variability of surface winds strongly influences the structure of the mixed layer. Daily, if not more frequent, surface fluxes must be imposed for a realistic surface mixed layer. Sea ice and ice shelves are important components of the coastal circulation. Ice isolates the ocean from exchange with the atmosphere, especially in the winter. Melting and freezing of both sea ice and glacial ice influence salinity and thereby the character of shelf water. These water

  7. Exchange across the shelf break at high southern latitudes

    NASA Astrophysics Data System (ADS)

    Klinck, J. M.; Dinniman, M. S.

    2010-01-01

    Exchange of water across the Antarctic shelf break has considerable scientific and societal importance due to its effects on circulation and biology of the region, conversion of water masses as part of the global overturning circulation and basal melt of glacial ice and the consequent effect on sea level rise. The focus in this paper is the onshore transport of warm, oceanic Circumpolar Deep Water (CDW); export of dense water from these shelves is equally important, but has been the focus of other recent papers and will not be considered here. A variety of physical mechanisms are described which could play a role in this onshore flux. The relative importance of some processes are evaluated by simple calculations. A numerical model for the Ross Sea continental shelf is used as an example of a more comprehensive evaluation of the details of cross-shelf break exchange. In order for an ocean circulation model simulate these processes at high southern latitudes, it needs to have high spatial resolution, realistic geometry and bathymetry. Grid spacing smaller than the first baroclinic radius deformation (a few km) is required to adequately represent the circulation. Because of flow-topography interactions, bathymetry needs to be represented at these same small scales. Atmospheric conditions used to force these circulation models also need to be known at a similar small spatial resolution (a few km) in order to represent orographically controlled winds (coastal jets) and katabatic winds. Significantly, time variability of surface winds strongly influences the structure of the mixed layer. Daily, if not more frequent, surface fluxes must be imposed for a realistic surface mixed layer. Sea ice and ice shelves are important components of the coastal circulation. Ice isolates the ocean from exchange with the atmosphere, especially in the winter. Melting and freezing of both sea ice and glacial ice influence salinity and thereby the character of shelf water. These water mass

  8. High Performance Bulk Thermoelectric Materials

    SciTech Connect

    Ren, Zhifeng

    2013-03-31

    Over 13 plus years, we have carried out research on electron pairing symmetry of superconductors, growth and their field emission property studies on carbon nanotubes and semiconducting nanowires, high performance thermoelectric materials and other interesting materials. As a result of the research, we have published 104 papers, have educated six undergraduate students, twenty graduate students, nine postdocs, nine visitors, and one technician.

  9. Panelized high performance multilayer insulation

    NASA Technical Reports Server (NTRS)

    Burkley, R. A.; Shriver, C. B.; Stuckey, J. M.

    1968-01-01

    Multilayer insulation coverings with low conductivity foam spacers are interleaved with quarter mil aluminized polymer film radiation shields to cover flight type liquid hydrogen tankage of space vehicles with a removable, structurally compatible, lightweight, high performance cryogenic insulation capable of surviving extended space mission environments.

  10. High performance rolling element bearing

    NASA Technical Reports Server (NTRS)

    Bursey, Jr., Roger W. (Inventor); Olinger, Jr., John B. (Inventor); Owen, Samuel S. (Inventor); Poole, William E. (Inventor); Haluck, David A. (Inventor)

    1993-01-01

    A high performance rolling element bearing (5) which is particularly suitable for use in a cryogenically cooled environment, comprises a composite cage (45) formed from glass fibers disposed in a solid lubricant matrix of a fluorocarbon polymer. The cage includes inserts (50) formed from a mixture of a soft metal and a solid lubricant such as a fluorocarbon polymer.

  11. High performance bilateral telerobot control.

    PubMed

    Kline-Schoder, Robert; Finger, William; Hogan, Neville

    2002-01-01

    Telerobotic systems are used when the environment that requires manipulation is not easily accessible to humans, as in space, remote, hazardous, or microscopic applications or to extend the capabilities of an operator by scaling motions and forces. The Creare control algorithm and software is an enabling technology that makes possible guaranteed stability and high performance for force-feedback telerobots. We have developed the necessary theory, structure, and software design required to implement high performance telerobot systems with time delay. This includes controllers for the master and slave manipulators, the manipulator servo levels, the communication link, and impedance shaping modules. We verified the performance using both bench top hardware as well as a commercial microsurgery system. PMID:15458092

  12. High performance storable propellant resistojet

    NASA Technical Reports Server (NTRS)

    Vaughan, C. E.

    1992-01-01

    From 1965 until 1985 resistojets were used for a limited number of space missions. Capability increased in stages from an initial application using a 90 W gN2 thruster operating at 123 sec specific impulse (Isp) to a 830 W N2H4 thruster operating at 305 sec Isp. Prior to 1985 fewer than 100 resistojets were known to have been deployed on spacecraft. Building on this base NASA embarked upon the High Performance Storable Propellant Resistojet (HPSPR) program to significantly advance the resistojet state-of-the-art. Higher performance thrusters promised to increase the market demand for resistojets and enable space missions requiring higher performance. During the program three resistojets were fabricated and tested. High temperature wire and coupon materials tests were completed. A life test was conducted on an advanced gas generator.

  13. Measured performance of the heat exchanger in the NASA icing research tunnel under severe icing and dry-air conditions

    NASA Technical Reports Server (NTRS)

    Olsen, W.; Vanfossen, J.; Nussle, R.

    1987-01-01

    Measurements were made of the pressure drop and thermal perfomance of the unique refrigeration heat exchanger in the NASA Lewis Icing Research Tunnel (IRT) under severe icing and frosting conditions and also with dry air. This data will be useful to those planning to use or extend the capability of the IRT and other icing facilities (e.g., the Altitude Wind Tunnel-AWT). The IRT heat exchanger and refrigeration system is able to cool air passing through the test section down to at least a total temperature of -30 C (well below icing requirements), and usually up to -2 C. The system maintains a uniform temperature across the test section at all airspeeds, which is more difficult and time consuming at low airspeeds, at high temperatures, and on hot, humid days when the cooling towers are less efficient. The very small surfaces of the heat exchanger prevent any icing cloud droplets from passing through it and going through the tests section again. The IRT heat exchanger was originally designed not to be adversely affected by severe icing. During a worst-case icing test the heat exchanger iced up enough so that the temperature uniformaity was no worse than about +/- 1 deg C. The conclusion is that the heat exchanger design performs well.

  14. HIGH ASPECT RATIO ION EXCHANGE RESIN BED - HYDRAULIC RESULTS FOR SPERICAL RESIN BEADS

    SciTech Connect

    Duignan, M; Charles Nash, C; Timothy Punch, T

    2007-09-27

    A principal role of the DOE Savannah River Site is to safely dispose of a large volume of liquid nuclear waste held in many storage tanks. An in-tank ion exchange unit is being considered for cesium removal to accelerate waste processing. This unit is planned to have a relatively high bed height to diameter ratio (10:1). Complicating the design is the need to cool the ion exchange media; therefore, the ion exchange column will have a central cooling core making the flow path annular. To separate cesium from waste the media being considered is made of resorcinol formaldehyde resin deposited on spherical plastic beads and is a substitute for a previously tested resin made of crystalline silicotitanate. This spherical media not only has an advantage of being mechanically robust, but, unlike its predecessor, it is also reusable, that is, loaded cesium can be removed through elution and regeneration. Resin regeneration leads to more efficient operation and less spent resin waste, but its hydraulic performance in the planned ion exchange column was unknown. Moreover, the recycling process of this spherical resorcinol formaldehyde causes its volume to significantly shrink and swell. To determine the spherical media's hydraulic demand a linearly scaled column was designed and tested. The waste simulant used was prototypic of the wastes' viscosity and density. This paper discusses the hydraulic performance of the media that will be used to assist in the design of a full-scale unit.

  15. Prototype Vent Gas Heat Exchanger for Exploration EVA - Performance and Manufacturing Characteristics

    NASA Technical Reports Server (NTRS)

    Quinn, Gregory J.; Strange, Jeremy; Jennings, Mallory

    2013-01-01

    NASA is developing new portable life support system (PLSS) technologies, which it is demonstrating in an unmanned ground based prototype unit called PLSS 2.0. One set of technologies within the PLSS provides suitable ventilation to an astronaut while on an EVA. A new component within the ventilation gas loop is a liquid-to-gas heat exchanger to transfer excess heat from the gas to the thermal control system s liquid coolant loop. A unique bench top prototype heat exchanger was built and tested for use in PLSS 2.0. The heat exchanger was designed as a counter-flow, compact plate fin type using stainless steel. Its design was based on previous compact heat exchangers manufactured by United Technologies Aerospace Systems (UTAS), but was half the size of any previous heat exchanger model and one third the size of previous liquid-to-gas heat exchangers. The prototype heat exchanger was less than 40 cubic inches and weighed 2.57 lb. Performance of the heat exchanger met the requirements and the model predictions. The water side and gas side pressure drops were less 0.8 psid and 0.5 inches of water, respectively, and an effectiveness of 94% was measured at the nominal air side pressure of 4.1 psia.

  16. High energy products in exchange-coupled nanocomposite films

    SciTech Connect

    Liu, J.P.; Liu, Y.; Skomski, R.; Sellmyer, D.J.

    1999-09-01

    Several systems of nanocomposite thin films have been prepared by plasma sputtering and heat treatment. By choosing suitable multilayer structures of the as-deposited films and subsequent heat-treatment processes, the nanostructures of the films have been tailored. The thermal processing is the key to control the morphology. Appropriate heat-treatment processes have been found for the systems studied, which result in the desired nanostructures. For the first time a nearly ideal nanostructure with the soft-phase grains embedded homogeneously in the hard phase grains has been obtained for the FePt-Fe{sub 1{minus}x}Pt{sub x} (x{approximately}0.3) system. Effective intergrain exchange coupling has been realized. As a consequence, high energy products up to 50 MGOe have been achieved.

  17. High Performance Tools And Technologies

    SciTech Connect

    Collette, M R; Corey, I R; Johnson, J R

    2005-01-24

    This goal of this project was to evaluate the capability and limits of current scientific simulation development tools and technologies with specific focus on their suitability for use with the next generation of scientific parallel applications and High Performance Computing (HPC) platforms. The opinions expressed in this document are those of the authors, and reflect the authors' current understanding and functionality of the many tools investigated. As a deliverable for this effort, we are presenting this report describing our findings along with an associated spreadsheet outlining current capabilities and characteristics of leading and emerging tools in the high performance computing arena. This first chapter summarizes our findings (which are detailed in the other chapters) and presents our conclusions, remarks, and anticipations for the future. In the second chapter, we detail how various teams in our local high performance community utilize HPC tools and technologies, and mention some common concerns they have about them. In the third chapter, we review the platforms currently or potentially available to utilize these tools and technologies on to help in software development. Subsequent chapters attempt to provide an exhaustive overview of the available parallel software development tools and technologies, including their strong and weak points and future concerns. We categorize them as debuggers, memory checkers, performance analysis tools, communication libraries, data visualization programs, and other parallel development aides. The last chapter contains our closing information. Included with this paper at the end is a table of the discussed development tools and their operational environment.

  18. Thermal performance of perforated plate matrix heat exchangers with effects from outer wall and flow channel geometry

    NASA Astrophysics Data System (ADS)

    Sunil Kumar, S.; Ratna Raju, L.; Nandi, T. K.

    2015-12-01

    The performance of high effectiveness (high NTU) perforated plate matrix heat exchangers (MHEs) is dependent on the geometry of the flow channels, as well as the longitudinal heat conduction through the outer walls. The effect of the above factors on the performance of MHEs is investigated in this paper numerically. The results obtained with the present model are validated with our own experimental results as well as those in the literature. The results show a strong influence of longitudinal heat conduction through the outer wall on the performance of MHEs. A parametric study has been carried out to arrive at the optimum flow channel geometry under given operating conditions.

  19. THERMAL PERFORMANCE ANALYSIS FOR SMALL ION-EXCHANGE CESIUM REMOVAL PROCESS

    SciTech Connect

    Lee, S.; King, W.

    2009-12-29

    The In-Riser Ion Exchange program focuses on the development of in-tank systems to decontaminate high level waste (HLW) salt solutions at the Savannah River Site (SRS) and the Hanford Site. Small Column Ion Exchange (SCIX) treatment for cesium removal is a primary in-riser technology for decontamination prior to final waste immobilization in Saltstone. Through this process, radioactive cesium from the salt solution is adsorbed onto the ion exchange media which is packed within a flow-through column. Spherical Resorcinol-Formaldehyde (RF) is being considered as the ion exchange media for the application of this technology at both sites. A packed column loaded with media containing radioactive cesium generates significant heat from radiolytic decay. Under normal operating conditions, process fluid flow through the column can provide adequate heat removal from the columns. However, in the unexpected event of loss of fluid flow or fluid drainage from the column, the design must be adequate to handle the thermal load to avoid unacceptable temperature excursions. Otherwise, hot spots may develop locally which could degrade the performance of the ion-exchange media or the temperature could rise above column safety limits. Data exists which indicates that performance degradation with regard to cesium removal occurs with RF at 65C. In addition, the waste supernate solution will boil around 130C. As a result, two temperature limits have been assumed for this analysis. An additional upset scenario was considered involving the loss of the supernate solution due to inadvertent fluid drainage through the column boundary. In this case, the column containing the loaded media could be completely dry. This event is expected to result in high temperatures that could damage the column or cause the RF sorbent material to undergo undesired physical changes. One objective of these calculations is to determine the range of temperatures that should be evaluated during testing with the RF

  20. Synthesis, structural characterization, and performance evaluation of resorcinol-formaldehyde (R-F) ion-exchange resin

    SciTech Connect

    Hubler, T.L.; Franz, J.A.; Shaw, W.J.; Bryan, S.A.; Hallen, R.T.; Brown, G.N.; Bray, L.A.; Linehan, J.C.

    1995-08-01

    The 177 underground storage tanks at the DOE`s Hanford Site contain an estimated 180 million tons of high-level radioactive wastes. It is desirable to remove and concentrate the highly radioactive fraction of the tank wastes for vitrification. Resorcinol-formaldehyde (R-F) resin, an organic ion-exchange resin with high selectivity and capacity for the cesium ion, which is a candidate ion-exchange material for use in remediation of tank wastes. The report includes information on the structure/function analysis of R-F resin and the synthetic factors that affect performance of the resin. CS-100, a commercially available phenol-formaldehyde (P-F) resin, and currently the baseline ion-exchanger for removal of cesium ion at Hanford, is compared with the R-F resin. The primary structural unit of the R-F resin was determined to consist of a 1,2,3,4-tetrasubstituted resorcinol ring unit while CS-100, was composed mainly of a 1,2,4-trisubstituted ring. CS-100 shows the presence of phenoxy-ether groups, and this may account for the much lower decontamination factor of CS-100 for cesium ion. Curing temperatures for the R-F resin were found to be optimal at 105--130C. At lower temperatures, insufficient curing, hence crosslinking, of the polymer resin occurs and selectivity for cesium drops. Curing at elevated temperatures leads to chemical degradation. Optimal particle size for R-F resin is in the range of 20--50 mesh-sized particles. R-F resin undergoes chemical degradation or oxidation which destroys ion-exchange sites. The ion-exchange sites (hydroxyl groups) are converted to quinones and ketones. CS-100, though it has much lower performance for cesium ion-exchange, is significantly more chemically stable than R-F resin. To gamma radiation, CS-100 is more radiolytically stable than R-F resin.

  1. High performance magnetically controllable microturbines.

    PubMed

    Tian, Ye; Zhang, Yong-Lai; Ku, Jin-Feng; He, Yan; Xu, Bin-Bin; Chen, Qi-Dai; Xia, Hong; Sun, Hong-Bo

    2010-11-01

    Reported in this paper is two-photon photopolymerization (TPP) fabrication of magnetic microturbines with high surface smoothness towards microfluids mixing. As the key component of the magnetic photoresist, Fe(3)O(4) nanoparticles were carefully screened for homogeneous doping. In this work, oleic acid stabilized Fe(3)O(4) nanoparticles synthesized via high-temperature induced organic phase decomposition of an iron precursor show evident advantages in particle morphology. After modification with propoxylated trimethylolpropane triacrylate (PO(3)-TMPTA, a kind of cross-linker), the magnetic nanoparticles were homogeneously doped in acrylate-based photoresist for TPP fabrication of microstructures. Finally, a magnetic microturbine was successfully fabricated as an active mixing device for remote control of microfluids blending. The development of high quality magnetic photoresists would lead to high performance magnetically controllable microdevices for lab-on-a-chip (LOC) applications. PMID:20721411

  2. 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.

  3. New, high performance rotating parachute

    SciTech Connect

    Pepper, W.B. Jr.

    1983-01-01

    A new rotating parachute has been designed primarily for recovery of high performance reentry vehicles. Design and development/testing results are presented from low-speed wind tunnel testing, free-flight deployments at transonic speeds and tests in a supersonic wind tunnel at Mach 2.0. Drag coefficients of 1.15 based on the 2-ft diameter of the rotor have been measured in the wind tunnel. Stability of the rotor is excellent.

  4. High performance ammonium nitrate propellant

    NASA Technical Reports Server (NTRS)

    Anderson, F. A. (Inventor)

    1979-01-01

    A high performance propellant having greatly reduced hydrogen chloride emission is presented. It is comprised of: (1) a minor amount of hydrocarbon binder (10-15%), (2) at least 85% solids including ammonium nitrate as the primary oxidizer (about 40% to 70%), (3) a significant amount (5-25%) powdered metal fuel, such as aluminum, (4) a small amount (5-25%) of ammonium perchlorate as a supplementary oxidizer, and (5) optionally a small amount (0-20%) of a nitramine.

  5. Prototype Vent Gas Heat Exchanger for Exploration EVA - Performance and Manufacturing Characteristics

    NASA Technical Reports Server (NTRS)

    Jennings, Mallory; Quinn, Gregory; Strange, Jeremy

    2012-01-01

    NASA is developing new portable life support system (PLSS) technologies, which it is demonstrating in an unmanned ground based prototype unit called PLSS 2.0. One set of technologies within the PLSS provides suitable ventilation to an astronaut while on an EVA. A new component within the ventilation gas loop is a liquid-to-gas heat exchanger to transfer excess heat from the gas to the thermal control system's liquid coolant loop. A unique bench top prototype heat exchanger was built and tested for use in PLSS 2.0. The heat exchanger was designed as a counter-flow, compact plate fin type using stainless steel. Its design was based on previous compact heat exchangers manufactured by United Technologies Aerospace Systems, but was half the size of any previous heat exchanger model and one third the size of previous liquid-to-gas heat exchangers. The prototype heat exchanger was less than 40 cubic inches and weighed 2.6 lb. The water side and gas side pressure drops were 0.8 psid and 0.5 inches of water, respectively. Performance of the heat exchanger at the nominal pressure of 4.1 psia was measured at 94%, while a gas inlet pressure of 25 psia resulted in an effectiveness of 84%. These results compared well with the model, which was scaled for the small size. Modeling of certain phenomena that affect performance, such as flow distribution in the headers was particularly difficult due to the small size of the heat exchanger. Data from the tests has confirmed the correction factors that were used in these parts of the model.

  6. High Efficiency, High Performance Clothes Dryer

    SciTech Connect

    Peter Pescatore; Phil Carbone

    2005-03-31

    This program covered the development of two separate products; an electric heat pump clothes dryer and a modulating gas dryer. These development efforts were independent of one another and are presented in this report in two separate volumes. Volume 1 details the Heat Pump Dryer Development while Volume 2 details the Modulating Gas Dryer Development. In both product development efforts, the intent was to develop high efficiency, high performance designs that would be attractive to US consumers. Working with Whirlpool Corporation as our commercial partner, TIAX applied this approach of satisfying consumer needs throughout the Product Development Process for both dryer designs. Heat pump clothes dryers have been in existence for years, especially in Europe, but have not been able to penetrate the market. This has been especially true in the US market where no volume production heat pump dryers are available. The issue has typically been around two key areas: cost and performance. Cost is a given in that a heat pump clothes dryer has numerous additional components associated with it. While heat pump dryers have been able to achieve significant energy savings compared to standard electric resistance dryers (over 50% in some cases), designs to date have been hampered by excessively long dry times, a major market driver in the US. The development work done on the heat pump dryer over the course of this program led to a demonstration dryer that delivered the following performance characteristics: (1) 40-50% energy savings on large loads with 35 F lower fabric temperatures and similar dry times; (2) 10-30 F reduction in fabric temperature for delicate loads with up to 50% energy savings and 30-40% time savings; (3) Improved fabric temperature uniformity; and (4) Robust performance across a range of vent restrictions. For the gas dryer development, the concept developed was one of modulating the gas flow to the dryer throughout the dry cycle. Through heat modulation in a

  7. 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.

  8. The effect of high temperatures on tropical forest gas exchange.

    NASA Astrophysics Data System (ADS)

    Doughty, C. E.; Goulden, M.; Miller, S.; Da Rocha, H.

    2006-12-01

    Further research is required to understand the sensitivity of tropical forest to climate warming. Previous research has shown that tropical forest photosynthesis decreases and respiration increases at high leaf temperatures and that tree growth is reduced in years with higher average air temperatures (Clark et al 2003). Models indicate that the climate related destruction of the Amazon forest will amplify global warming by 1.5¢ª C, resulting in a mean temperature increase of 5.5¢ª C, as compared with 4¢ª C without this carbon cycle feedback (Cox et al 2000). These studies demonstrate the importance of temperature on tropical forest gas exchange. At the LBA Tapajos km 83 site we determined what controls tropical leaf temperature and how temperature affects photosynthesis and respiration. Sunlit leaves were substantially warmer than air temperatures and this had a negative effect on photosynthesis and stomatal conductance. We used eddy flux data to compare intervals of 10 minute cloudy periods followed by 20 minute sunny periods to see if similar trends could be seen at both the leaf and canopy level. The longer the sunny interval the warmer the canopy became and canopy conductance and CO2 exchange declined correspondingly. As the canopy warmed u* increased which increased turbulence and kept the canopy temperature from rising more. Long light intervals can cause heat stress in tropical forests but due to the very cloudy nature of the tropics such intervals are rare. However, if the tropics become both warmer and less cloudy such heat stress will increase.

  9. Heat exchanger performance calculations for enhanced-tube condenser applications

    SciTech Connect

    Rabas, T.J.

    1992-01-01

    The lack of a prediction method is sometimes used for the rejection of enhanced tubes for some condenser applications even though there is ample data from single-tube condensing experiments. Three methods are discussed that can be used to rate and/or size these multitube units based on the single-tube experimental results. The Kern vertical-number correction appears to be quite adequate for most operating conditions, the exceptions being large sizes and/or deep vacuum operation. The bundle-factor method is preferred for these applications; however, field test results are required to obtain this factor. If performance data are not available, pointwise or numerical methods are required but special care must be taken to insure that the adverse effects of noncondensable gas pockets and the saturation-temperature depression are properly addressed.

  10. Heat exchanger performance calculations for enhanced-tube condenser applications

    SciTech Connect

    Rabas, T.J.

    1992-07-01

    The lack of a prediction method is sometimes used for the rejection of enhanced tubes for some condenser applications even though there is ample data from single-tube condensing experiments. Three methods are discussed that can be used to rate and/or size these multitube units based on the single-tube experimental results. The Kern vertical-number correction appears to be quite adequate for most operating conditions, the exceptions being large sizes and/or deep vacuum operation. The bundle-factor method is preferred for these applications; however, field test results are required to obtain this factor. If performance data are not available, pointwise or numerical methods are required but special care must be taken to insure that the adverse effects of noncondensable gas pockets and the saturation-temperature depression are properly addressed.

  11. Novel proton exchange membrane fuel cell electrodes to improve performance of reversible fuel cell systems

    NASA Astrophysics Data System (ADS)

    Brown, Tim Matthew

    Proton exchange membrane (PEM) fuel cells react fuel and oxidant to directly and efficiently produce electrical power, without the need for combustion, heat engines, or motor-generators. Additionally, PEM fuel cell systems emit zero to virtually zero criteria pollutants and have the ability to reduce CO2 emissions due to their efficient operation, including the production or processing of fuel. A reversible fuel cell (RFC) is one particular application for a PEM fuel cell. In this application the fuel cell is coupled with an electrolyzer and a hydrogen storage tank to complete a system that can store and release electrical energy. These devices can be highly tailored to specific energy storage applications, potentially surpassing the performance of current and future secondary battery technology. Like all PEM applications, RFCs currently suffer from performance and cost limitations. One approach to address these limitations is to improve the cathode performance by engineering more optimal catalyst layer geometry as compared to the microscopically random structure traditionally used. Ideal configurations are examined and computer modeling shows promising performance improvements are possible. Several novel manufacturing methods are used to build and test small PEM fuel cells with novel electrodes. Additionally, a complete, dynamic model of an RFC system is constructed and the performance is simulated using both traditional and novel cathode structures. This work concludes that PEM fuel cell microstructures can be tailored to optimize performance based on design operating conditions. Computer modeling results indicate that novel electrode microstructures can improve fuel cell performance, while experimental results show similar performance gains that bolster the theoretical predictions. A dynamic system model predicts that novel PEM fuel cell electrode structures may enable RFC systems to be more competitive with traditional energy storage technology options.

  12. Heat exchange effects on the performance of a clearance-sealed piston prover for gas flow measurements

    NASA Astrophysics Data System (ADS)

    Kutin, J.; Bobovnik, G.; Bajsić, I.

    2015-12-01

    This paper deals with heat exchange effects in a compact, high-speed, clearance-sealed version of a piston prover for gas flow measurements that has the temperature measurements limited to the time-averaged temperature of the gas flow. A lumped-element mathematical model is used to study the physical background of the heat exchange effects. Experimental testing is performed to validate the theoretical results, estimate the required temperature homogeneity in the piston prover and propose a modified measurement model that considers the heat exchange effects. These effects are almost linearly related to the temperature difference between the gas flow into the piston prover and the cylinder wall, with the sensitivity coefficient being dependent on the measured flow rate. The piston-prover configuration with the gas temperature sensor in the mixed inlet /outlet flow is found to be advantageous in comparison to a measurement of the inlet temperature.

  13. Space shuttle launch vehicle performance trajectory, exchange ratios, and dispersion analysis

    NASA Technical Reports Server (NTRS)

    Toelle, R. G.; Blackwell, D. L.; Lott, L. N.

    1973-01-01

    A baseline space shuttle performance trajectory for Mission 3A launched from WTR has been generated. Design constraints of maximum dynamic pressure, longitudinal acceleration, and delivered payload were satisfied. Payload exchange ratios are presented with explanation on use. Design envelopes of dynamic pressure, SRB staging point, aerodynamic heating and flight performance reserves are calculated and included.

  14. Support from the top: supervisors' perceived organizational support as a moderator of leader-member exchange to satisfaction and performance relationships.

    PubMed

    Erdogan, Berrin; Enders, Jeanne

    2007-03-01

    The authors hypothesized that supervisors' perceived organizational support (POS) would moderate the relationships between leader-member exchange (LMX), job satisfaction, and job performance. On the basis of social exchange theory, supervisors' exchanges with the organization and subordinates should be interconnected. The authors expected that supervisors with high POS would have more resources to exchange with subordinates. Thus, supervisor POS should enhance the relationships between LMX and job satisfaction and LMX and job performance for subordinates. Hierarchical linear modeling analysis provided support for the hypotheses in a sample of 210 subordinates and 38 supervisors of a grocery store chain. The positive relationship between LMX and job satisfaction was stronger when supervisors had high POS. Moreover, LMX was related to performance only when supervisors had high POS. PMID:17371081

  15. High Performance Parallel Computational Nanotechnology

    NASA Technical Reports Server (NTRS)

    Saini, Subhash; Craw, James M. (Technical Monitor)

    1995-01-01

    At a recent press conference, NASA Administrator Dan Goldin encouraged NASA Ames Research Center to take a lead role in promoting research and development of advanced, high-performance computer technology, including nanotechnology. Manufacturers of leading-edge microprocessors currently perform large-scale simulations in the design and verification of semiconductor devices and microprocessors. Recently, the need for this intensive simulation and modeling analysis has greatly increased, due in part to the ever-increasing complexity of these devices, as well as the lessons of experiences such as the Pentium fiasco. Simulation, modeling, testing, and validation will be even more important for designing molecular computers because of the complex specification of millions of atoms, thousands of assembly steps, as well as the simulation and modeling needed to ensure reliable, robust and efficient fabrication of the molecular devices. The software for this capacity does not exist today, but it can be extrapolated from the software currently used in molecular modeling for other applications: semi-empirical methods, ab initio methods, self-consistent field methods, Hartree-Fock methods, molecular mechanics; and simulation methods for diamondoid structures. In as much as it seems clear that the application of such methods in nanotechnology will require powerful, highly powerful systems, this talk will discuss techniques and issues for performing these types of computations on parallel systems. We will describe system design issues (memory, I/O, mass storage, operating system requirements, special user interface issues, interconnects, bandwidths, and programming languages) involved in parallel methods for scalable classical, semiclassical, quantum, molecular mechanics, and continuum models; molecular nanotechnology computer-aided designs (NanoCAD) techniques; visualization using virtual reality techniques of structural models and assembly sequences; software required to

  16. High Performance Pulse Tube Cryocoolers

    NASA Astrophysics Data System (ADS)

    Olson, J. R.; Roth, E.; Champagne, P.; Evtimov, B.; Nast, T. C.

    2008-03-01

    Lockheed Martin's Advanced Technology Center has been developing pulse tube cryocoolers for more than ten years. Recent innovations include successful testing of four-stage coldheads, no-load temperature below 4 K, and the recent development of a high-efficiency compressor. This paper discusses the predicted performance of single and multiple stage pulse tube coldheads driven by our new 6 kg "M5Midi" compressor, which is capable of 90% efficiency with 200 W input power, and a maximum input power of 1000 W. This compressor retains the simplicity of earlier LM-ATC compressors: it has a moving magnet and an external electrical coil, minimizing organics in the working gas and requiring no electrical penetrations through the pressure wall. Motor losses were minimized during design, resulting in a simple, easily-manufactured compressor with state-of-the-art motor efficiency. The predicted cryocooler performance is presented as simple formulae, allowing an engineer to include the impact of a highly-optimized cryocooler into a full system analysis. Performance is given as a function of the heat rejection temperature and the cold tip temperatures and cooling loads.

  17. High performance aerated lagoon systems

    SciTech Connect

    Rich, L.

    1999-08-01

    At a time when less money is available for wastewater treatment facilities and there is increased competition for the local tax dollar, regulatory agencies are enforcing stricter effluent limits on treatment discharges. A solution for both municipalities and industry is to use aerated lagoon systems designed to meet these limits. This monograph, prepared by a recognized expert in the field, provides methods for the rational design of a wide variety of high-performance aerated lagoon systems. Such systems range from those that can be depended upon to meet secondary treatment standards alone to those that, with the inclusion of intermittent sand filters or elements of sequenced biological reactor (SBR) technology, can also provide for nitrification and nutrient removal. Considerable emphasis is placed on the use of appropriate performance parameters, and an entire chapter is devoted to diagnosing performance failures. Contents include: principles of microbiological processes, control of algae, benthal stabilization, design for CBOD removal, design for nitrification and denitrification in suspended-growth systems, design for nitrification in attached-growth systems, phosphorus removal, diagnosing performance.

  18. Performance of multi tubes in tube helically coiled as a compact heat exchanger

    NASA Astrophysics Data System (ADS)

    Nada, S. A.; El Shaer, W. G.; Huzayyin, A. S.

    2014-12-01

    Multi tubes in tube helically coiled heat exchanger is proposed as a compact heat exchanger. Effects of heat exchanger geometric parameters and fluid flow parameters; namely number of inner tubes, annulus hydraulic diameter, Reynolds numbers and input heat flux, on performance of the heat exchanger are experimentally investigated. Different coils with different numbers of inner tubes, namely 1, 3, 4 and 5 tubes, were tested. Results showed that coils with 3 inner tubes have higher values of heat transfer coefficient and compactness parameter (bar{h} Ah ). Pressure drop increases with increasing both of Reynolds number and number of inner tubes. Correlations of average Nusselt number were deduced from experimental data in terms of Reynolds number, Prandtl number, Number of inner coils tubes and coil hydraulic diameter. Correlations prediction was compared with experimental data and the comparison was fair enough.

  19. Secondary heat exchanger design and comparison for advanced high temperature reactor

    SciTech Connect

    Sabharwall, P.; Kim, E. S.; Siahpush, A.; McKellar, M.; Patterson, M.

    2012-07-01

    Next generation nuclear reactors such as the advanced high temperature reactor (AHTR) are designed to increase energy efficiency in the production of electricity and provide high temperature heat for industrial processes. The efficient transfer of energy for industrial applications depends on the ability to incorporate effective heat exchangers between the nuclear heat transport system and the industrial process heat transport system. This study considers two different types of heat exchangers - helical coiled heat exchanger and printed circuit heat exchanger - as possible options for the AHTR secondary heat exchangers with distributed load analysis and comparison. Comparison is provided for all different cases along with challenges and recommendations. (authors)

  20. Performance of annular high frequency thermoacoustic engines

    NASA Astrophysics Data System (ADS)

    Rodriguez, Ivan A.

    This thesis presents studies of the behavior of miniature annular thermoacoustic prime movers and the imaging of the complex sound fields using PIV inside the small acoustic wave guides when driven by a temperature gradient. Thermoacoustic engines operating in the standing wave mode are limited in their acoustic efficiency by a high degree of irreversibility that is inherent in how they work. Better performance can be achieved by using traveling waves in the thermoacoustic devices. This has led to the development of an annular high frequency thermoacoustic prime mover consisting of a regenerator, which is a random stack in-between a hot and cold heat exchanger, inside an annular waveguide. Miniature devices were developed and studied with operating frequencies in the range of 2-4 kHz. This corresponds to an average ring circumference of 11 cm for the 3 kHz device, the resonator bore being 6 mm. A similar device of 11 mm bore, length of 18 cm was also investigated; its resonant frequency was 2 kHz. Sound intensities as high as 166.8 dB were generated with limited heat input. Sound power was extracted from the annular structure by an impedance-matching side arm. The nature of the acoustic wave generated by heat was investigated using a high speed PIV instrument. Although the acoustic device appears symmetric, its performance is characterized by a broken symmetry and by perturbations that exist in its structure. Effects of these are observed in the PIV imaging; images show axial and radial components. Moreover, PIV studies show effects of streaming and instabilities which affect the devices' acoustic efficiency. The acoustic efficiency is high, being of 40% of Carnot. This type of device shows much promise as a high efficiency energy converter; it can be reduced in size for microcircuit applications.

  1. HIGH PERFORMANCE EBIS FOR RHIC.

    SciTech Connect

    ALESSI,J.; BEEBE, E.; GOULD, O.; KPONOU, A.; LOCKEY, R.; PIKIN, A.; RAPARIA, D.; RITTER, J.; SNYDSTRUP, L.

    2007-06-25

    An Electron Beam Ion Source (EBIS), capable of producing high charge states and high beam currents of any heavy ion species in short pulses, is ideally suited for injection into a synchrotron. An EBIS-based, high current, heavy ion preinjector is now being built at Brookhaven to provide increased capabilities for the Relativistic Heavy Ion Collider (RHIC), and the NASA Space Radiation Laboratory (NSRL). Benefits of the new preinjector include the ability to produce ions of any species, fast switching between species to serve the simultaneous needs of multiple programs, and lower operating and maintenance costs. A state-of-the-art EBIS, operating with an electron beam current of up to 10 A, and producing multi-milliamperes of high charge state heavy ions, has been developed at Brookhaven, and has been operating very successfully on a test bench for several years. The present performance of this high-current EBIS is presented, along with details of the design of the scaled-up EBIS for RHIC, and the status of its construction. Other aspects of the project, including design and construction of the heavy ion RFQ, Linac, and matching beamlines, are also mentioned.

  2. High Performance Proactive Digital Forensics

    NASA Astrophysics Data System (ADS)

    Alharbi, Soltan; Moa, Belaid; Weber-Jahnke, Jens; Traore, Issa

    2012-10-01

    With the increase in the number of digital crimes and in their sophistication, High Performance Computing (HPC) is becoming a must in Digital Forensics (DF). According to the FBI annual report, the size of data processed during the 2010 fiscal year reached 3,086 TB (compared to 2,334 TB in 2009) and the number of agencies that requested Regional Computer Forensics Laboratory assistance increasing from 689 in 2009 to 722 in 2010. Since most investigation tools are both I/O and CPU bound, the next-generation DF tools are required to be distributed and offer HPC capabilities. The need for HPC is even more evident in investigating crimes on clouds or when proactive DF analysis and on-site investigation, requiring semi-real time processing, are performed. Although overcoming the performance challenge is a major goal in DF, as far as we know, there is almost no research on HPC-DF except for few papers. As such, in this work, we extend our work on the need of a proactive system and present a high performance automated proactive digital forensic system. The most expensive phase of the system, namely proactive analysis and detection, uses a parallel extension of the iterative z algorithm. It also implements new parallel information-based outlier detection algorithms to proactively and forensically handle suspicious activities. To analyse a large number of targets and events and continuously do so (to capture the dynamics of the system), we rely on a multi-resolution approach to explore the digital forensic space. Data set from the Honeynet Forensic Challenge in 2001 is used to evaluate the system from DF and HPC perspectives.

  3. Performance Characteristics of Cross-Fin-Tube-Type Heat Exchanger for Air Conditioner

    NASA Astrophysics Data System (ADS)

    Sasaki, Naoe; Kakiyama, Shiro; Sanuki, Noriyoshi

    The effects of enhanced heat transfer tube with ability to control the heat transfer disturbance by mechanical tube expanding were experimentally investigated on the performance characteristics of air-cooled cross-fin-tube-type heat exchanger for air conditioner. Three kinds of the enhanced heat transfer tube were developed and used in the experiment. The enhanced heat transfer tube was a kind of spirally grooved tube and composed with the fins smaller than those of the conventional spirally grooved tube excepting four fins located in orthogonal position on the tube circumference. The optimum groove number to enhance the performance of heat exchanger was also shown.

  4. Tuning a High Transmission Ion Guide to Prevent Gas-Phase Proton Exchange During H/D Exchange MS Analysis.

    PubMed

    Guttman, Miklos; Wales, Thomas E; Whittington, Dale; Engen, John R; Brown, Jeffery M; Lee, Kelly K

    2016-04-01

    Hydrogen/deuterium exchange (HDX) mass spectrometry (MS) for protein structural analysis has been adopted for many purposes, including biopharmaceutical development. One of the benefits of examining amide proton exchange by mass spectrometry is that it can readily resolve different exchange regimes, as evidenced by either binomial or bimodal isotope patterns. By careful analysis of the isotope pattern during exchange, more insight can be obtained on protein behavior in solution. However, one must be sure that any observed bimodal isotope patterns are not artifacts of analysis and are reflective of the true behavior in solution. Sample carryover and certain stationary phases are known as potential sources of bimodal artifacts. Here, we describe an additional undocumented source of deuterium loss resulting in artificial bimodal patterns for certain highly charged peptides. We demonstrate that this phenomenon is predominantly due to gas-phase proton exchange between peptides and bulk solvent within the initial stages of high-transmission conjoined ion guides. Minor adjustments of the ion guide settings, as reported here, eliminate the phenomenon without sacrificing signal intensity. Such gas-phase deuterium loss should be appreciated for all HDX-MS studies using such ion optics, even for routine studies not focused on interpreting bimodal spectra. Graphical Abstract ᅟ. PMID:26810432

  5. Tuning a High Transmission Ion Guide to Prevent Gas-Phase Proton Exchange During H/D Exchange MS Analysis

    NASA Astrophysics Data System (ADS)

    Guttman, Miklos; Wales, Thomas E.; Whittington, Dale; Engen, John R.; Brown, Jeffery M.; Lee, Kelly K.

    2016-04-01

    Hydrogen/deuterium exchange (HDX) mass spectrometry (MS) for protein structural analysis has been adopted for many purposes, including biopharmaceutical development. One of the benefits of examining amide proton exchange by mass spectrometry is that it can readily resolve different exchange regimes, as evidenced by either binomial or bimodal isotope patterns. By careful analysis of the isotope pattern during exchange, more insight can be obtained on protein behavior in solution. However, one must be sure that any observed bimodal isotope patterns are not artifacts of analysis and are reflective of the true behavior in solution. Sample carryover and certain stationary phases are known as potential sources of bimodal artifacts. Here, we describe an additional undocumented source of deuterium loss resulting in artificial bimodal patterns for certain highly charged peptides. We demonstrate that this phenomenon is predominantly due to gas-phase proton exchange between peptides and bulk solvent within the initial stages of high-transmission conjoined ion guides. Minor adjustments of the ion guide settings, as reported here, eliminate the phenomenon without sacrificing signal intensity. Such gas-phase deuterium loss should be appreciated for all HDX-MS studies using such ion optics, even for routine studies not focused on interpreting bimodal spectra.

  6. Cryo-SEM of hydrated high temperature proton exchange membranes

    SciTech Connect

    Perry, Kelly A; More, Karren Leslie; Walker, Larry R; Benicewicz, Brian

    2009-01-01

    Alternative energy technologies, such as high temperature fuel cells and hydrogen pumps, rely on proton exchange membranes (PEM). A chemically and thermally stable PEM with rapid proton transport is sol-gel phosphoric acid (PA)-doped polybenzimidazole (PBI) membranes. It is believed that the key to the high ionic conductivity of PA-doped PBI membranes is related to the gel morphology. However, the gel structure and general morphology of this PA-doped PBI membrane has not been widely investigated. In an effort to understand the gel morphology, two SEM sample preparation methodologies have been developed for PA-doped PBI membranes. Due to the high vacuum environment of conventional SEM, the beam-sensitivity of these membranes was reduced with a mild 120 C heat treatment to remove excess water without structural rearrangement (as verified from wide angle X-ray scattering). Cryo-SEM has also been implemented for both initial and heated membranes. Cryo-SEM is known to prevent dehydration of the specimen and reduce beam-sensitivity. The SEM cross-section image (Fig. 1A) of the heated samples exhibit 3{micro}m spheroidal features that are elongated in the direction of the casting blade. These features are distorted to 2{micro}m under conventional SEM conditions (Fig. 1B). The fine-scale gel morphology image (Fig. 2) is composed of 65nm diameter domains and 30nm walls, which resembles a cellular structure. In the future, the PA-doped PBI membranes will be cryo-microtomed and cryotransferred for elemental analysis in a TEM.

  7. A numerical performance assessment of a commercial cardiopulmonary by-pass blood heat exchanger.

    PubMed

    Consolo, Filippo; Fiore, Gianfranco B; Pelosi, Alessandra; Reggiani, Stefano; Redaelli, Alberto

    2015-06-01

    We developed a numerical model, based on multi-physics computational fluid dynamics (CFD) simulations, to assist the design process of a plastic hollow-fiber bundle blood heat exchanger (BHE) integrated within the INSPIRE(TM), a blood oxygenator (OXY) for cardiopulmonary by-pass procedures, recently released by Sorin Group Italia. In a comparative study, we analyzed five different geometrical design solutions of the BHE module. Quantitative geometrical-dependent parameters providing a comprehensive evaluation of both the hemo- and thermo-dynamics performance of the device were extracted to identify the best-performing prototypical solution. A convenient design configuration was identified, characterized by (i) a uniform blood flow pattern within the fiber bundle, preventing blood flow shunting and the onset of stagnation/recirculation areas and/or high velocity pathways, (ii) an enhanced blood heating efficiency, and (iii) a reduced blood pressure drop. The selected design configuration was then prototyped and tested to experimentally characterize the device performance. Experimental results confirmed numerical predictions, proving the effectiveness of CFD modeling as a reliable tool for in silico identification of suitable working conditions of blood handling medical devices. Notably, the numerical approach limited the need for extensive prototyping, thus reducing the corresponding machinery costs and time-to-market. PMID:25890509

  8. High-temperature ceramic heat exchanger element for a solar thermal receiver

    NASA Technical Reports Server (NTRS)

    Strumpf, H. J.; Kotchick, D. M.; Coombs, M. G.

    1982-01-01

    A study has been completed on the development of a high-temperature ceramic heat exchanger element to be integrated into a solar reciver producing heated air. A number of conceptual designs were developed for heat exchanger elements of differing configuration. These were evaluated with respect to thermal performance, pressure drop, structural integrity, and fabricability. The final design selection identified a finned ceramic shell as the most favorable concept. The ceramic shell is surrounded by a larger metallic shell. The flanges of the two shells are sealed to provide a leak-tight pressure vessel. The ceramic shell is fabricated by an innovative combination of slip casting the receiver walls and precision casting the heat transfer finned plates. The fins are bonded to the shell during firing. Fabrication of a one-half scale demonstrator ceramic receiver has been completed.

  9. High-performance combinatorial algorithms

    SciTech Connect

    Pinar, Ali

    2003-10-31

    Combinatorial algorithms have long played an important role in many applications of scientific computing such as sparse matrix computations and parallel computing. The growing importance of combinatorial algorithms in emerging applications like computational biology and scientific data mining calls for development of a high performance library for combinatorial algorithms. Building such a library requires a new structure for combinatorial algorithms research that enables fast implementation of new algorithms. We propose a structure for combinatorial algorithms research that mimics the research structure of numerical algorithms. Numerical algorithms research is nicely complemented with high performance libraries, and this can be attributed to the fact that there are only a small number of fundamental problems that underlie numerical solvers. Furthermore there are only a handful of kernels that enable implementation of algorithms for these fundamental problems. Building a similar structure for combinatorial algorithms will enable efficient implementations for existing algorithms and fast implementation of new algorithms. Our results will promote utilization of combinatorial techniques and will impact research in many scientific computing applications, some of which are listed.

  10. High-Performance Bipropellant Engine

    NASA Technical Reports Server (NTRS)

    Biaglow, James A.; Schneider, Steven J.

    1999-01-01

    TRW, under contract to the NASA Lewis Research Center, has successfully completed over 10 000 sec of testing of a rhenium thrust chamber manufactured via a new-generation powder metallurgy. High performance was achieved for two different propellants, N2O4- N2H4 and N2O4 -MMH. TRW conducted 44 tests with N2O4-N2H4, accumulating 5230 sec of operating time with maximum burn times of 600 sec and a specific impulse Isp of 333 sec. Seventeen tests were conducted with N2O4-MMH for an additional 4789 sec and a maximum Isp of 324 sec, with a maximum firing duration of 700 sec. Together, the 61 tests totalled 10 019 sec of operating time, with the chamber remaining in excellent condition. Of these tests, 11 lasted 600 to 700 sec. The performance of radiation-cooled rocket engines is limited by their operating temperature. For the past two to three decades, the majority of radiation-cooled rockets were composed of a high-temperature niobium alloy (C103) with a disilicide oxide coating (R512) for oxidation resistance. The R512 coating practically limits the operating temperature to 1370 C. For the Earth-storable bipropellants commonly used in satellite and spacecraft propulsion systems, a significant amount of fuel film cooling is needed. The large film-cooling requirement extracts a large penalty in performance from incomplete mixing and combustion. A material system with a higher temperature capability has been matured to the point where engines are being readied for flight, particularly the 100-lb-thrust class engine. This system has powder rhenium (Re) as a substrate material with an iridium (Ir) oxidation-resistant coating. Again, the operating temperature is limited by the coating; however, Ir is capable of long-life operation at 2200 C. For Earth-storable bipropellants, this allows for the virtual elimination of fuel film cooling (some film cooling is used for thermal control of the head end). This has resulted in significant increases in specific impulse performance

  11. Optimization of an anion-exchange high performance liquid chromatography-inductively coupled plasma-mass spectrometric method for the speciation analysis of oxyanion-forming metals and metalloids in leachates from cement-based materials.

    PubMed

    Mulugeta, Mesay; Wibetoe, Grethe; Engelsen, Christian J; Lund, Walter

    2010-10-01

    A method was developed for the speciation analysis of the oxyanions of As(III), As(V), Cr(VI), Mo(VI), Sb(III), Sb(V), Se(IV), Se(VI) and V(V) in leachates from cement-based materials, based on anion-exchange HPLC coupled with ICP-MS. The method was optimized in a two-step multivariate approach: the effect of sample pH and mobile phase composition on resolution, peak symmetry and analysis time was studied. Optimum conditions were then identified for the significant experimental factors by studying their interdependence. A mobile phase composition of 20 mM ammonium nitrate, 50 mM ammonium tartrate and pH 9.5 was found to be a compromise optimum for the separation of the target analytes using isocratic elution. The optimum condition provided separation of the analytes in less than 6 min, at a mobile phase flow rate of 1.0 mL/min. The signal intensities of the analytes were improved by adding 1% methanol to the mobile phase. The limit of detection of the method was in the range 0.2-2.2 μg/L for the various species. The effect of sample constituents was studied using spiked concrete leachates. The method was used to determine the target oxyanionic species in leachates generated from a concrete material in the pH range 3.5-12.4; CrO(4)(2-), MoO(4)(2-) and VO(4)(3-) were detected in most of the leachates. PMID:20813376

  12. Performance analysis of the “intelligent” Kirchhoff-Law-Johnson-Noise secure key exchange

    NASA Astrophysics Data System (ADS)

    Smulko, Janusz

    2014-09-01

    The Kirchhoff-Law-Johnson-Noise (KLJN) secure key distribution system provides a way of exchanging information theoretic secure keys by measuring the random voltage and current through the wire connecting two different resistors at Alice's and Bob's ends. Recently new advanced protocols for the KLJN method have been proposed with enhanced performance. In this paper we analyze the KLJN system and compare with “intelligent” KLJN (iKLJN) scheme. This task requires the determination of the applied resistors and the identification of the various superpositions of known and unknown noise components. Some statistical tools to determine how the duration of the bit exchange window (averaging time) influences the performance of secure bit exchange will be explored.

  13. An experimental evaluation of capillary tube-suction line heat exchanger performance with R-152a

    SciTech Connect

    Bittle, R.R.; Stephenson, W.R.; Pate, M.B.

    1995-08-01

    Capillary tube-suction line heat exchanger performance correlations predicting mass flow rate and effective subcooling have been generated for refrigerant R-152a for application to household refrigerators. These prediction correlations were developed from experimental data taken over a range of applicable operating boundary conditions and heat exchanger geometries. Due to the large number of variables that could potentially influence heat exchanger performance, statistical methods were employed in designing the test plan and in reducing the data. For these experiments, the measured mass flow rate ranged between 6.5 and 15.5 lbm (2.95 and 7.03 kg/h), and the effective subcooling level ranged between 25 F and 50 F (13.9 C and 27.8 C). A comparison of the R-152a results to experimental data for R-12 was also made.

  14. High Performance Field Reversed Configurations

    NASA Astrophysics Data System (ADS)

    Binderbauer, Michl

    2014-10-01

    The field-reversed configuration (FRC) is a prolate compact toroid with poloidal magnetic fields. FRCs could lead to economic fusion reactors with high power density, simple geometry, natural divertor, ease of translation, and possibly capable of burning aneutronic fuels. However, as in other high-beta plasmas, there are stability and confinement concerns. These concerns can be addressed by introducing and maintaining a significant fast ion population in the system. This is the approach adopted by TAE and implemented for the first time in the C-2 device. Studying the physics of FRCs driven by Neutral Beam (NB) injection, significant improvements were made in confinement and stability. Early C-2 discharges had relatively good confinement, but global power losses exceeded the available NB input power. The addition of axially streaming plasma guns, magnetic end plugs as well as advanced surface conditioning leads to dramatic reductions in turbulence driven losses and greatly improved stability. As a result, fast ion confinement significantly improved and allowed for build-up of a dominant fast particle population. Under such appropriate conditions we achieved highly reproducible, long-lived, macroscopically stable FRCs with record lifetimes. This demonstrated many beneficial effects of large orbit particles and their performance impact on FRCs Together these achievements point to the prospect of beam-driven FRCs as a path toward fusion reactors. This presentation will review and expand on key results and present context for their interpretation.

  15. Candidate alloys for cost-effective, high-efficiency, high-temperature compact/foil heat-exchangers

    SciTech Connect

    Evans, Neal D; Maziasz, Philip J; Shingledecker, John P; Pint, Bruce A; Yamamoto, Yukinori

    2007-01-01

    Solid oxide fuel cell (SOFC) and molten carbonate fuel cell (MCFC) systems operate at high temperatures (up to 1000 C and 650 C, respectively), which makes them especially attractive sources for combined heat and power (CHP) cogeneration. However, improvements in the efficiency of heat exchange in these fuel cells require both development and careful processing of advanced cost-effective alloys for use in such high-temperature service conditions. The high-temperature properties of both sheet and foil forms of several alloys being considered for use in compact heat-exchangers (recuperators) have been characterized. Mechanical and creep-rupture testing, oxidation studies, and microstructural studies have been performed on commercially available sheet and foil forms of alloy 347, alloys 625, HR230, HR120, and the new AL20-25+Nb. These studies have led to a mechanistic understanding of the responses of these alloys to anticipated service conditions, and suggest that these alloys developed for gas- and micro-turbine recuperator applications are also suitable for use in fuel cell heat-exchangers. Additional work is still required to achieve foil forms with creep life comparable to thicker-section wrought product forms of the same alloys.

  16. DESIGN OF A COMPACT HEAT EXCHANGER FOR HEAT RECUPERATION FROM A HIGH TEMPERATURE ELECTROLYSIS SYSTEM

    SciTech Connect

    G. K. Housley; J.E. O'Brien; G.L. Hawkes

    2008-11-01

    Design details of a compact heat exchanger and supporting hardware for heat recuperation in a high-temperature electrolysis application are presented. The recuperative heat exchanger uses a vacuum-brazed plate-fin design and operates between 300 and 800°C. It includes corrugated inserts for enhancement of heat transfer coefficients and extended heat transfer surface area. Two recuperative heat exchangers are required per each four-stack electrolysis module. The heat exchangers are mated to a base manifold unit that distributes the inlet and outlet flows to and from the four electrolysis stacks. Results of heat exchanger design calculations and assembly details are also presented.

  17. High performance solar Stirling system

    NASA Technical Reports Server (NTRS)

    Stearns, J. W.; Haglund, R.

    1981-01-01

    A full-scale Dish-Stirling system experiment, at a power level of 25 kWe, has been tested during 1981 on the Test Bed Concentrator No. 2 at the Parabolic Dish Test Site, Edwards, CA. Test components, designed and developed primarily by industrial contractors for the Department of Energy, include an advanced Stirling engine driving an induction alternator, a directly-coupled solar receiver with a natural gas combustor for hybrid operation and a breadboard control system based on a programmable controller and standard utility substation components. The experiment demonstrated practicality of the solar Stirling application and high system performance into a utility grid. This paper describes the design and its functions, and the test results obtained.

  18. FPGA Based High Performance Computing

    SciTech Connect

    Bennett, Dave; Mason, Jeff; Sundararajan, Prasanna; Dellinger, Erik; Putnam, Andrew; Storaasli, Olaf O

    2008-01-01

    Current high performance computing (HPC) applications are found in many consumer, industrial and research fields. From web searches to auto crash simulations to weather predictions, these applications require large amounts of power by the compute farms and supercomputers required to run them. The demand for more and faster computation continues to increase along with an even sharper increase in the cost of the power required to operate and cool these installations. The ability of standard processor based systems to address these needs has declined in both speed of computation and in power consumption over the past few years. This paper presents a new method of computation based upon programmable logic as represented by Field Programmable Gate Arrays (FPGAs) that addresses these needs in a manner requiring only minimal changes to the current software design environment.

  19. High power ion thruster performance

    NASA Technical Reports Server (NTRS)

    Rawlin, Vincent K.; Patterson, Michael J.

    1987-01-01

    The ion thruster is one of several forms of space electric propulsion being considered for use on future SP-100-based missions. One possible major mission ground rule is the use of a single Space Shuttle launch. Thus, the mass in orbit at the reactor activation altitude would be limited by the Shuttle mass constraints. When the spacecraft subsystem masses are subtracted from this available mass limit, a maximum propellant mass may be calculated. Knowing the characteristics of each type of electric thruster allows maximum values of total impulse, mission velocity increment, and thrusting time to be calculated. Because ion thrusters easily operate at high values of efficiency (60 to 70%) and specific impulse (3000 to 5000 sec), they can impart large values of total impulse to a spacecraft. They also can be operated with separate control of the propellant flow rate and exhaust velocity. This paper presents values of demonstrated and projected performance of high power ion thrusters used in an analysis of electric propulsion for an SP-100 based mission.

  20. Shape optimization of a printed-circuit heat exchanger to enhance thermal-hydraulic performance

    SciTech Connect

    Lee, S. M.; Kim, K. Y.

    2012-07-01

    Printed circuit heat exchanger (PCHE) is recently considered as a recuperator for the high temperature gas cooled reactor. In this work, the zigzag-channels of a PCHE have been optimized by using three-dimensional Reynolds-Averaged Navier-Stokes (RANS) analysis and response surface approximation (RSA) modeling technique to enhance thermal-hydraulic performance. Shear stress transport turbulence model is used as a turbulence closure. The objective function is defined as a linear combination of the functions related to heat transfer and friction loss of the PCHE, respectively. Three geometric design variables viz., the ratio of the radius of the fillet to hydraulic diameter of the channels, the ratio of wavelength to hydraulic diameter of the channels, and the ratio of wave height to hydraulic diameter of the channels, are used for the optimization. Design points are selected through Latin-hypercube sampling. The optimal design is determined through the RSA model which uses RANS derived calculations at the design points. The results show that the optimum shape enhances considerably the thermal-hydraulic performance than a reference shape. (authors)

  1. Effect of long-term organic removal on ion exchange properties and performance during sewage tertiary treatment by conventional anion exchange resins.

    PubMed

    Sun, Jian; Li, Xiaofeng; Quan, Ying; Yin, Yunjun; Zheng, Shaokui

    2015-10-01

    This study evaluated the long-term dissolved organic matter (DOM), phosphorus and nitrogen removal performance of a commercially available conventional anion exchange resin (AER) from actual secondary effluent (SE) in a sewage treatment plant based on a pilot-scale operation (2.2 m(3) d(-1), 185 cycles, 37,000 bed volume, 1.5 years). Particular emphasis was given to the potential effect of DOM fouling on the ion exchange properties and performance during the long-term operation. Despite the large range of COD (15.6-33.5 mg L(-1)), BOD5 (3.0-5.6 mg L(-1)), DOC (6.5-24.2 mg L(-1)), and UV254 (UV absorption at 254 nm) (0.108-0.229 cm(-1)) levels in the SE, the removal efficiencies of the AER for the aforementioned parameters were 43±12%, 46±15%, 45±9%, and 72±4%, respectively. Based on three-dimensional fluorescence excitation-emission matrix data, i.e., the fluorescence intensities of four regions (peaks A-D), all organic components of the SE were effectively removed (peak A 74%, peak B 48%, peak C 55%, and peak D 45%) following the adsorption. The AER effluent still has considerable polycyclic aromatic hydrocarbons' ecological hazard on freshwater fishes when they were significantly removed from SE. The obvious DOM fouling on the AER, identified by color change, had no significant influence on the long-term removal of the representative inorganic anions (averaging 95±4% phosphate, 100±0% SO4(2-), and 62±17% NO3(-)) and AER properties (including total exchange capacity, moisture content, and true density). The conventional AER can produce high quality reclaimed water from SE at a low operational cost. PMID:25996990

  2. High quality exchange rotations in spin qubits using symmetric gating

    NASA Astrophysics Data System (ADS)

    Martins, F.; Malinowski, F. K.; Nissen, P. D.; Marcus, C. M.; Kuemmeth, F.; Barnes, E.; Gardner, G. C.; Fallahi, S.; Manfra, M. J.

    We present results on a singlet-triplet qubit implemented in a GaAs/AlGaAs heterostructure and we show that exchange oscillations can be realized either by tilting the double well potential, the conventional method, or by symmetrically lowering the barrier, as originally suggested by Loss and DiVincenzo. The two methods are compared here. We find that lowering the barrier between dots has much less relative exchange noise compared to tilting the potential. Since exchange rotations are sensitive to electrical noise and relatively insensitive to nuclear noise, this yields significantly enhanced free induction decay times and quality factors. Our results are comparable to those reported recently in silicon quantum dot devices, obtained using similar techniques. Support through IARPA-MQCO, LPS-MPO-CMTC, Army Research Office, and the Danish National Research Foundation is acknowledged.

  3. Experimental and numerical investigation on air-side performance of fin-and-tube heat exchangers with various fin patterns

    SciTech Connect

    Tang, L.H.; Zeng, M.; Wang, Q.W.

    2009-07-15

    Air-side heat transfer and friction characteristics of five kinds of fin-and-tube heat exchangers, with the number of tube rows (N = 12) and the diameter of tubes (D{sub o} = 18 mm), have been experimentally investigated. The test samples consist of five types of fin configurations: crimped spiral fin, plain fin, slit fin, fin with delta-wing longitudinal vortex generators (VGs) and mixed fin with front 6-row vortex-generator fin and rear 6-row slit fin. The heat transfer and friction factor correlations for different types of heat exchangers were obtained with the Reynolds numbers ranging from 4000 to 10000. It was found that crimped spiral fin provides higher heat transfer and pressure drop than the other four fins. The air-side performance of heat exchangers with the above five fins has been evaluated under three sets of criteria and it was shown that the heat exchanger with mixed fin (front vortex-generator fin and rear slit fin) has better performance than that with fin with delta-wing vortex generators, and the slit fin offers best heat transfer performance at high Reynolds numbers. Based on the correlations of numerical data, Genetic Algorithm optimization was carried out, and the optimization results indicated that the increase of VG attack angle or length, or decrease of VG height may enhance the performance of vortex-generator fin. The heat transfer performances for optimized vortex-generator fin and slit fin at hand have been compared with numerical method. (author)

  4. A cation exchange model to describe Cs+ sorption at high ionic strength in subsurface sediments at Hanford site, USA.

    PubMed

    Liu, Chongxuan; Zachara, John M; Smith, Steve C

    2004-02-01

    A theoretical and experimental study of cation exchange in high ionic strength electrolytes was performed using pristine subsurface sediments from the U.S. Department of Energy Hanford site. These sediments are representative of the site contaminated sediments impacted by release of high level waste (HLW) solutions containing 137Cs+ in NaNO3 brine. The binary exchange behavior of Cs+-Na+, Cs+-K+, and Na+-K+ was measured over a range in electrolyte concentration. Vanselow selectivity coefficients (Kv) that were calculated from the experimental data using Pitzer model ion activity corrections for aqueous species showed monotonic increases with increasing electrolyte concentrations. The influence of electrolyte concentration was greater on the exchange of Na+-Cs+ than K+-Cs+, an observation consistent with the differences in ion hydration energy of the exchanging cations. A previously developed two-site ion exchange model [Geochimica et Cosmochimica Acta 66 (2002) 193] was modified to include solvent (water) activity changes in the exchanger phase through application of the Gibbs-Duhem equation. This water activity-corrected model well described the ionic strength effect on binary Cs+ exchange, and was extended to the ternary exchange system of Cs+-Na+-K+ on the pristine sediment. The model was also used to predict 137Cs+ distribution between sediment and aqueous phase (Kd) beneath a leaked HLW tank in Hanfordd's S-SX tank using the analytical aqueous data from the field and the binary ion exchange coefficients for the pristine sediment. The Kd predictions closely followed the trend in the field data and were improved by consideration of water activity effects that were considerable in certain regions of the vadose zone plume. PMID:14734247

  5. A cation exchange model to describe Cs + sorption at high ionic strength in subsurface sediments at Hanford site, USA

    NASA Astrophysics Data System (ADS)

    Liu, Chongxuan; Zachara, John M.; Smith, Steve C.

    2004-02-01

    A theoretical and experimental study of cation exchange in high ionic strength electrolytes was performed using pristine subsurface sediments from the U.S. Department of Energy Hanford site. These sediments are representative of the site contaminated sediments impacted by release of high level waste (HLW) solutions containing 137Cs + in NaNO 3 brine. The binary exchange behavior of Cs +-Na +, Cs +-K +, and Na +-K + was measured over a range in electrolyte concentration. Vanselow selectivity coefficients ( Kv) that were calculated from the experimental data using Pitzer model ion activity corrections for aqueous species showed monotonic increases with increasing electrolyte concentrations. The influence of electrolyte concentration was greater on the exchange of Na +-Cs + than K +-Cs +, an observation consistent with the differences in ion hydration energy of the exchanging cations. A previously developed two-site ion exchange model [Geochimica et Cosmochimica Acta 66 (2002) 193] was modified to include solvent (water) activity changes in the exchanger phase through application of the Gibbs-Duhem equation. This water activity-corrected model well described the ionic strength effect on binary Cs + exchange, and was extended to the ternary exchange system of Cs +-Na +-K + on the pristine sediment. The model was also used to predict 137Cs + distribution between sediment and aqueous phase ( Kd) beneath a leaked HLW tank in Hanfordd's S-SX tank using the analytical aqueous data from the field and the binary ion exchange coefficients for the pristine sediment. The Kd predictions closely followed the trend in the field data and were improved by consideration of water activity effects that were considerable in certain regions of the vadose zone plume.

  6. Ground Source Heat Pump Sub-Slab Heat Exchange Loop Performance in a Cold Climate

    SciTech Connect

    Mittereder, Nick; Poerschke, Andrew

    2013-11-01

    This report presents a cold-climate project that examines an alternative approach to ground source heat pump (GSHP) ground loop design. The innovative ground loop design is an attempt to reduce the installed cost of the ground loop heat exchange portion of the system by containing the entire ground loop within the excavated location beneath the basement slab. Prior to the installation and operation of the sub-slab heat exchanger, energy modeling using TRNSYS software and concurrent design efforts were performed to determine the size and orientation of the system. One key parameter in the design is the installation of the GSHP in a low-load home, which considerably reduces the needed capacity of the ground loop heat exchanger. This report analyzes data from two cooling seasons and one heating season.

  7. High Performance Solution Processable TFTs

    NASA Astrophysics Data System (ADS)

    Gundlach, David

    2008-03-01

    Organic-based electronic devices offer the potential to significantly impact the functionality and pervasiveness of large-area electronics. We report on soluble acene-based organic thin film transistors (OTFTs) where the microstructure of as-cast films can be precisely controlled via interfacial chemistry. Chemically tailoring the source/drain contact interface is a novel route to self-patterning of soluble small molecule organic semiconductors and enables the growth of highly ordered regions along opposing contact edges which extend into the transistor channel. The unique film forming properties of soluble fluorinated anthradithiophenes allows us to fabricate high performance OTFTs, OTFT circuits, and to deterministically study the influence of the film microstructure on the electrical characteristics of devices. Most recently we have grown single crystals of soluble fluorinated anthradithiophenes by vapor transport method allowing us to probe deeper into their intrinsic properties and determine the potential and limitations of this promising family of oligomers for use in organic-based electronic devices. Co-Authors: O. D. Jurchescu^1,4, B. H. Hamadani^1, S. K. Park^4, D. A. Mourey^4, S. Subramanian^5, A. J. Moad^2, R. J. Kline^3, L. C. Teague^2, J. G. Kushmerick^2, L. J. Richter^2, T. N. Jackson^4, and J. E. Anthony^5 ^1Semiconductor Electronics Division, ^2Surface and Microanalysis Science Division, ^3Polymers Division, National Institute of Standards and Technology, Gaithersburg, MD 20899 ^4Department of Electrical Engineering, The Pennsylvania State University, University Park, PA 16802 ^5Department of Chemistry, University of Kentucky, Lexington, KY 40506-0055

  8. Generalization of Logarithmic Mean Temperature Difference Method for Heat Exchanger Performance Analysis

    NASA Astrophysics Data System (ADS)

    Utamura, Motoaki; Nikitin, Konstantin; Kato, Yasuyoshi

    A generalized mean temperature difference (GMTD) method for heat exchangers is proposed. In the analysis of the performance of heat exchangers logarithmic temperature difference (LMTD) method has been widely used. This method, however, limits its application to those heating media with constant physical property. In turn GMTD method allows analysis with physical property distributed in an entire heat exchanger. Temperature profiles of the heat exchanger taken as function of heat load in place of axial position, mean temperature difference is evaluated numerically. It is mathematically demonstrated that LMTD method is an extremity of the GMTD method in the case of constant physical property. The GMTD method is applied to a hot water supplier with supercritical carbon dioxide as a heating media which is attracting attention as energy saving tactics. The hot water supplier operates under the condition of pseudo critical point of carbon dioxide where specific heat behaves anomaly. Incorporating GMTD method averaged overall heat transfer coefficient and subsequently formula of local Nusselt number are successfully derived for microchannel heat exchanger while formal application of LMTD method is found to give poor results i.e. two times less value with a larger error. This proves the validity of GMTD method.

  9. Ground Source Heat Pump Sub-Slab Heat Exchange Loop Performance in a Cold Climate

    SciTech Connect

    Mittereder, N.; Poerschke, A.

    2013-11-01

    This report presents a cold-climate project that examines an alternative approach to ground source heat pump (GSHP) ground loop design. The innovative ground loop design is an attempt to reduce the installed cost of the ground loop heat exchange portion of the system by containing the entire ground loop within the excavated location beneath the basement slab. Prior to the installation and operation of the sub-slab heat exchanger, energy modeling using TRNSYS software and concurrent design efforts were performed to determine the size and orientation of the system. One key parameter in the design is the installation of the GSHP in a low-load home, which considerably reduces the needed capacity of the ground loop heat exchanger. This report analyzes data from two cooling seasons and one heating season. Upon completion of the monitoring phase, measurements revealed that the initial TRNSYS simulated horizontal sub-slab ground loop heat exchanger fluid temperatures and heat transfer rates differed from the measured values. To determine the cause of this discrepancy, an updated model was developed utilizing a new TRNSYS subroutine for simulating sub-slab heat exchangers. Measurements of fluid temperature, soil temperature, and heat transfer were used to validate the updated model.

  10. High performance Cu adhesion coating

    SciTech Connect

    Lee, K.W.; Viehbeck, A.; Chen, W.R.; Ree, M.

    1996-12-31

    Poly(arylene ether benzimidazole) (PAEBI) is a high performance thermoplastic polymer with imidazole functional groups forming the polymer backbone structure. It is proposed that upon coating PAEBI onto a copper surface the imidazole groups of PAEBI form a bond with or chelate to the copper surface resulting in strong adhesion between the copper and polymer. Adhesion of PAEBI to other polymers such as poly(biphenyl dianhydride-p-phenylene diamine) (BPDA-PDA) polyimide is also quite good and stable. The resulting locus of failure as studied by XPS and IR indicates that PAEBI gives strong cohesive adhesion to copper. Due to its good adhesion and mechanical properties, PAEBI can be used in fabricating thin film semiconductor packages such as multichip module dielectric (MCM-D) structures. In these applications, a thin PAEBI coating is applied directly to a wiring layer for enhancing adhesion to both the copper wiring and the polymer dielectric surface. In addition, a thin layer of PAEBI can also function as a protection layer for the copper wiring, eliminating the need for Cr or Ni barrier metallurgies and thus significantly reducing the number of process steps.

  11. ALMA high performance nutating subreflector

    NASA Astrophysics Data System (ADS)

    Gasho, Victor L.; Radford, Simon J. E.; Kingsley, Jeffrey S.

    2003-02-01

    For the international ALMA project"s prototype antennas, we have developed a high performance, reactionless nutating subreflector (chopping secondary mirror). This single axis mechanism can switch the antenna"s optical axis by +/-1.5" within 10 ms or +/-5" within 20 ms and maintains pointing stability within the antenna"s 0.6" error budget. The light weight 75 cm diameter subreflector is made of carbon fiber composite to achieve a low moment of inertia, <0.25 kg m2. Its reflecting surface was formed in a compression mold. Carbon fiber is also used together with Invar in the supporting structure for thermal stability. Both the subreflector and the moving coil motors are mounted on flex pivots and the motor magnets counter rotate to absorb the nutation reaction force. Auxiliary motors provide active damping of external disturbances, such as wind gusts. Non contacting optical sensors measure the positions of the subreflector and the motor rocker. The principle mechanical resonance around 20 Hz is compensated with a digital PID servo loop that provides a closed loop bandwidth near 100 Hz. Shaped transitions are used to avoid overstressing mechanical links.

  12. HIGH CURRENT D- PRODUCTION BY CHARGE EXCHANGE IN SODIUM

    SciTech Connect

    Hooper, E.B.; Poulsen, P.; Pincosy, P.A.

    1981-02-01

    A beam of D{sup -} ions has been produced at 7-13 keV, with currents up to 2.2 {angstrom}, using charge exchange in sodium vapor. The beam profile is bi-Gaussian with angular divergence 0.7{sup o} x 2.8{sup o} and peak current density 15 mA/cm{sup 2}. The characteristics of the beam are in excellent agreement with predictions based on atomic cross sections. The sodium vapor target is formed by a jet directed across the beam. The sodium density drops rapidly in the beamline downstream from the charge exchange region, decreasing three orders of magnitude in 15 cm. Measurement and analysis of the plasma accompanying the beam demonstrate that plasma densities nearly equal to the beam density are obtained 1 m from the charge exchange medium. The plasma produced in the sodium is thus well confined to the charge exchange region and does not propagate along the beam.

  13. The Effect of Circuiting Arrangement on the Thermal Performance of Refrigeration Mixtures in Tube-and-Fin Condensing Heat Exchangers

    SciTech Connect

    Chen, D.T.; Conklin, J.C.

    1999-03-15

    For the pure or azeotropic refrigerants typically used in present air conditioning and refrigeration applications, the refrigerant changes phase at a constant temperature. Thus, the refrigerant circuiting arrangement such as crossfiow, counterfiow, or cross-counterflow, has no effect on the thermal performance. For zeotropic refrigerant mixtures, however, the phase-change occurs over a temperature range, or "glide", and the refrigerant circuiting arrangement, or flow path through the heat exchanger, can affect the thermal performance of both the heat exchangers as well as the overall efficiency of the vapor compression cooling cycle. The effects of tsvo diflerent circuiting arrangements on the thermal performance of a zeotropic retligerant mixture and an almost azeotropic refrigerant mixture in a four-row cross-countertlow heat exchanger arrangement are reported here. The two condensers differ only in the manner of circuiting the refrigerant tubes, where one has refrigerant always flowing downward in the active heat transfer region ("identical order") and the other has refrigerant alternating flow direction in the active heat transfer region ("inverted order"). All other geometric parameters, such as bce are% fin louver geometry, refrigerant tube size and enhancement etc., are the same for both heat exchangers. One refrigerant mixture (R-41OA) un&rgoes a small temperature change ("low glide") during phase change, and the other retligerant mixture (a multi- component proprietary mixture) has a substantial temperature change ("high glide") of approximately 10"C during the phase change process. The overall thermal conductance, two-phase conductance, and pressure drop are presented. For the flow conditions of these tests, which are representative of resi&ntial cooling conditions, inverted order circuiting is more desirable than identical order. The potential thermal advantages of the i&ntical order arrangement for high-glide zeotropic refrigerant mixtures are negated

  14. The effect of circuiting arrangement on the thermal performance of refrigerant mixtures in tube-and-fin condensing heat exchangers

    SciTech Connect

    Conklin, J.C.; Chen, D.T.

    1999-07-01

    For the pure or azeotropic refrigerants typically used in present air conditioning and refrigeration applications, the refrigerant changes phase at a constant temperature. Thus, the refrigerant circuiting arrangement such as crossflow, counterflow, or cross-counterflow, has no effect on the thermal performance. For zeotropic refrigerant mixtures, however, the phase-change occurs over a temperature range, or glide, and the refrigerant circuiting arrangement, or flow path through the heat exchanger, can affect the thermal performance of both the heat exchangers as well as the overall efficiency of the vapor compression cooling cycle. The effects of two different circuiting arrangements on the thermal performance of a zeotropic refrigerant mixture and an almost azeotropic refrigerant mixture and an almost azeotropic refrigerant mixture in a four-row cross-counterflow heat exchanger arrangement are reported here. The two condensers differ only in the manner of circuiting the refrigerant tubes, where one has refrigerant always flowing downward in the active heat transfer region (identical order) and the other has refrigerant alternating flow direction in the active heat transfer region (inverted order). All other geometric parameters, such as face area, fin louver geometry, refrigerant tube size and enhancement, etc., are the same for both heat exchangers. One refrigerant mixture (R-410A) undergoes a small temperature change (low glide) during phase change, and the other refrigerant mixture (a multi-component proprietary mixture) has a substantial temperature change (high glide) of approximately 10 C during the phase change process. The overall thermal conductance, two-phase conductance, and pressure drop are presented. For the flow conditions of these tests, which are representative of residential cooling conditions, inverted order circuiting is more desirable than identical order. The potential thermal advantages of the identical order arrangement for high

  15. Application of ion-exchange cartridge clean-up in food analysis. V. Simultaneous determination of sulphonamide antibacterials in animal liver and kidney using high-performance liquid chromatography with ultraviolet and mass spectrometric detection.

    PubMed

    Ito, Y; Oka, H; Ikai, Y; Matsumoto, H; Miyazaki, Y; Nagase, H

    2000-11-10

    A simple, rapid, and reliable method for the determination of residual sulphonamide antibacterials (SAs) (sulfadiazine, sulfamerazine, sulfadimidine, sulfamethoxypiridazine, sulfisozole, sulfamonomethoxine, sulfamethoxazole, sulfisoxazole, sulfadimethoxine, and sulfaquinoxaline) in animal liver and kidney was developed using a combination of clean-up on a Bond Elut PSA cartridge and HPLC with UV detection. The SAs were extracted with ethyl acetate and then dissolved in 5 ml of 50 v/v% ethyl acetate-n-hexane after being evaporated to dryness. For clean-up of the crude sample, the resuspended extract was applied to a Bond Elut PAS (primary/secondary amine cartridge), and then SAs were eluted from the cartridge using 5 ml of 20 v/v% acetonitrile-0.05 M ammonium formate before being analysed by HPLC. Recoveries of the SAs at the levels of 0.5 and 0.1 microg/g were 70.8-98.2%, the rerative standard deviation were less than 7.0%, and the detection limits were 0.03 microg/g. The present analysis method of SAs in animal kidney and liver using HPLC with a clean-up procedure was demonstrated to be highly applicable to the direct LC-MS-MS analysis without any modification. PMID:11185627

  16. Heat and mass transfer performances on plate fin and tube heat exchangers with dehumidification

    SciTech Connect

    Seshimo, Y.; Ogawa, K.; Marumoto, K.; Fujii, M. )

    1990-09-01

    The authors discuss how they conducted an experimental study on the air side performance of a single-row plate fin and tube heat exchanger in moist air where mass transfer exist under a relatively low driving potential. The results are as follows: The heat transfer with dehumidification is about 20% greater than that with only sensible heat transfer. Also the air side pressure drop is about 30-40% greater. The reason, as clarified by visual observations, comes from the condensate effect. To study how the condensate film affects performance, the presence of the stagnant condensate in the heat exchanger was modeled as an apparent change of the heat exchanger geometry, and the equivalent thickness of the condensate film was calculated from the increase in the air side pressure drop. As a result, if the presence of condensate in the heat exchanger is considered, then the heat transfer with dehumidification can be treated in the same way as with only sensible heat transfer. The analogy between heat and mass transfer does not strictly hold, the experimental results being closed to the Lewis Law.

  17. Effects of biofouling on ion transport through cation exchange membranes and microbial fuel cell performance.

    PubMed

    Choi, Mi-Jin; Chae, Kyu-Jung; Ajayi, Folusho F; Kim, Kyoung-Yeol; Yu, Hye-Weon; Kim, Chang-Won; Kim, In S

    2011-01-01

    This study examines the effects of biofouling on the electrochemical properties of cation exchange membranes (CEMs), such as membrane electrical resistance (MER), specific proton conductivity (SC), and ion transport number (t(+)), in addition to on microbial fuel cell (MFC) performance. CEM biofouling using a 15.5 ± 4.6 μm biofilm was found to slightly increase the MER from 15.65 Ω cm(2) (fresh Nafion) to 19.1 Ω cm(2), whereas an increase of almost two times was achieved when the electrolyte was changed from deionized water to an anolyte containing a high cation concentration supporting bacterial growth. The simple physical cleaning of CEMs had little effect on the Coulombic efficiency (CE), whereas replacing a biofouled CEM with new one resulted in considerable increase of up to 59.3%, compared to 45.1% for a biofouled membrane. These results clearly suggest the internal resistance increase of MFC was mainly caused by the sulfonate functional groups of CEM being occupied with cations contained in the anolyte, rather than biofouling itself. PMID:20659795

  18. Human performance on negative slope schedules of points exchangeable for money: a failure of molar maximization.

    PubMed Central

    Jacobs, E A; Hackenberg, T D

    2000-01-01

    Panel pressing was generated and maintained in 5 adult humans by schedules of points exchangeable for money. Following exposure to a variable-interval 30-s schedule and to a linear variable-interval 30-s schedule (which permitted points to accumulate in an unseen "store" in the absence of responding), subjects were exposed to a series of conditions with a point-subtraction contingency arranged conjointly with the linear variable-interval schedule. Specifically, points were added to the store according to the linear-variable interval 30-s schedule and were subtracted from the store according to a ratio schedule. Ratio value varied across conditions and was determined individually for each subject such that the subtraction contingency would result in an approximately 50% reduction in the rate of point delivery. Conditions that included the subtraction contingency were termed negative slope schedules because the feedback functions were negatively sloped across all response rates greater than the inverse of the variable-interval schedule, in this case, two per minute. Overall response rates varied inversely with the subtraction ratio, indicating sensitivity to the negative slope conditions, but were in excess of that required by accounts based on strict maximization of overall reinforcement rate. Performance was also not well described by a matching-based account. Detailed analyses of response patterning revealed a consistent two-state pattern in which bursts of high-rate responding alternated with periods of prolonged pausing, perhaps reflecting the joint influence of local and overall reinforcement rates. PMID:10866350

  19. The sorption of quercetin by high-basicity anion exchangers

    NASA Astrophysics Data System (ADS)

    Udalova, N. A.; Karpov, S. I.; Selemenev, V. F.; Sharmar, I. A.

    2009-06-01

    The sorption of quercetin on anionites with various porosities in the OH- and Cl- forms was studied under static conditions. The equilibrium (distribution coefficients K p) and kinetic (effective diffusion coefficients D eff) parameters of quercetin sorption on AV-17-2P and AV-17-6M anionites in the Cl- and OH- forms were calculated. The mechanism of quercetin interactions with the anion exchangers was studied by electron microscopy and IR spectroscopy.

  20. Process Heat Exchanger Options for the Advanced High Temperature Reactor

    SciTech Connect

    Piyush Sabharwall; Eung Soo Kim; Michael McKellar; Nolan Anderson

    2011-06-01

    The work reported herein is a significant intermediate step in reaching the final goal of commercial-scale deployment and usage of molten salt as the heat transport medium for process heat applications. The primary purpose of this study is to aid in the development and selection of the required heat exchanger for power production and process heat application, which would support large-scale deployment.

  1. Process Heat Exchanger Options for Fluoride Salt High Temperature Reactor

    SciTech Connect

    Piyush Sabharwall; Eung Soo Kim; Michael McKellar; Nolan Anderson

    2011-04-01

    The work reported herein is a significant intermediate step in reaching the final goal of commercial-scale deployment and usage of molten salt as the heat transport medium for process heat applications. The primary purpose of this study is to aid in the development and selection of the required heat exchanger for power production and process heat application, which would support large-scale deployment.

  2. Flight crew performance when pilot-flying and pilot-not-flying duties are exchanged

    NASA Technical Reports Server (NTRS)

    Orlady, H. W.

    1982-01-01

    This study compares reports from the ASRS database depicting operational anomalies related to flight crew performance when pilot-flying and pilot-not-flying duties were exchanged. A greater number of near midair collisions, takeoff anomalies, and crossing altitude deviations were reported when the Captain was flying. More altitude deviations, near midair collisions during approach, and landing incidents occurred when the First Officer was flying. There were differences in monitoring effectiveness and in the type and distribution of information transfer problems associated with the anomalies. In addition, a number of crew performance factors were noted that were not affected by the exchange of duties. Several of these were deemed important enough to be included as matter of general interest.

  3. Preparation and characterization of high capacity, strong cation-exchange fiber based adsorbents.

    PubMed

    Schwellenbach, Jan; Taft, Florian; Villain, Louis; Strube, Jochen

    2016-05-20

    Motivated by the demand for more economical capture and polishing steps in downstream processing of protein therapeutics, a novel strong cation-exchange chromatography stationary phase based on polyethylene terephthalate (PET) high surface area short-cut fibers is presented. The fiber surface is modified by grafting glycidyl methacrylate (GMA) via surface-initiated atom transfer radical polymerization (SI-ATRP) and a subsequent derivatization leading to sulfonic acid groups. The obtained cation-exchange fibers have been characterized and compared to commercially available resin and membrane based adsorbers. High volumetric static binding capacities for lysozyme (90mg/mL) and polyclonal human IgG (hIgG, 92mg/mL) were found, suggesting an efficient multi-layer binding within the grafted hydrogel layer. A packed bed of randomly orientated fibers has been tested for packing efficiency, permeability and chromatographic performance. High dynamic binding capacities for lysozyme (50mg/mL) and hIgG (54mg/mL) were found nearly independent of the bed-residence time, revealing a fast mass-transport mechanism. Height equivalent to a theoretical plate (HETP) values in the order of 0.1 cm and a peak asymmetry factor (AF) of 1.8 have been determined by tracer experiments. Additionally inverse size-exclusion chromatography (iSEC) revealed a bimodal structure within the fiber bed, consisting of larger transport channels, formed by the voidage between the fibers, and a hydrogel layer with porous properties. PMID:27106396

  4. A High-Resolution Modeling Study of the Bosphorus Strait Dynamics and Exchange Flows

    NASA Astrophysics Data System (ADS)

    Sözer, Adil; Sannino, Gianmaria; Özsoy, Emin

    2013-04-01

    An all-time modelling challenge aims to establish a sound understanding of the high energy environment of the Turkish Straits System, relating to inter-basin water and material transports and their influence on the sensitive ecosystems of the adjacent seas. As a first step in this direction, well resolved, high level, physically representative predictive models of the Bosphorus Strait exchange flow hydrodynamics are developed, adequately representing its complex topography, hydraulic controls, dissipative hydraulic jumps, mixing and turbulence mechanisms, with the application of appropriate basin boundary and initial conditions and judiciously selected numerical and physical model options. Both the ROMS and MITgcm models are used and compared for performance. Idealized and real case model results successfully reproduce observed flow features. The unique maximal exchange regime of the Bosphorus Strait, with hydraulic controls are demonstrated, although frictional effects, especially of the highly irregular lateral boundaries, are found to be extremely important, associated with mixing and entrainment and nonlinear dynamics determining the two-way fluxes as a function of sea-level changes across the strait. The intercomparison of ROMS and MITgcm results are extremely satisfactory in the basic elements of the flow, except for some small differences.

  5. High energy efficiency and high power density proton exchange membrane fuel cells: Electrode kinetics and mass transport

    NASA Technical Reports Server (NTRS)

    Srinivasan, Supramaniam; Velev, Omourtag A.; Parthasathy, Arvind; Manko, David J.; Appleby, A. John

    1991-01-01

    The development of proton exchange membrane (PEM) fuel cell power plants with high energy efficiencies and high power densities is gaining momentum because of the vital need of such high levels of performance for extraterrestrial (space, underwater) and terrestrial (power source for electric vehicles) applications. Since 1987, considerable progress has been made in achieving energy efficiencies of about 60 percent at a current density of 200 mA/sq cm and high power densities (greater than 1 W/sq cm) in PEM fuel cells with high (4 mg/sq cm) or low (0.4 mg/sq cm) platinum loadings in electrodes. The following areas are discussed: (1) methods to obtain these high levels of performance with low Pt loading electrodes - by proton conductor impregnation into electrodes, localization of Pt near front surface; (2) a novel microelectrode technique which yields electrode kinetic parameters for oxygen reduction and mass transport parameters; (3) demonstration of lack of water transport from anode to cathode; (4) modeling analysis of PEM fuel cell for comparison with experimental results and predicting further improvements in performance; and (5) recommendations of needed research and development for achieving the above goals.

  6. Cell performance of Pd-Sn catalyst in passive direct methanol alkaline fuel cell using anion exchange membrane

    NASA Astrophysics Data System (ADS)

    Kim, Jandee; Momma, Toshiyuki; Osaka, Tetsuya

    Direct methanol alkaline fuel cell (DMAFC) using anion exchange membrane (AEM) was operated in passive condition. Cell with AEM exhibits a higher open circuit voltage (OCV) and superior cell performance than those in cell using Nafion. From the concentration dependences of methanol, KOH in fuel and ionomer in anode catalyst layer, it is found that the key factors are to improve the ionic conductivity at the anode and to form a favorable ion conductive path in catalyst layer in order to enhance the cell performance. In addition, by using home-made Pd-Sn/C catalyst as a cathode catalyst on DMAFC, the membrane electrode assembly (MEA) using Pd-Sn/C catalyst as cathode exhibits the higher performance than the usual commercially available Pt/C catalyst in high methanol concentration. Therefore, the Pd-Sn/C catalyst with high tolerance for methanol is expected as the promising oxygen reduction reaction (ORR) catalyst in DMAFC.

  7. Analysis of high-resolution foreign exchange data of USD-JPY for 13 years

    NASA Astrophysics Data System (ADS)

    Mizuno, Takayuki; Kurihara, Shoko; Takayasu, Misako; Takayasu, Hideki

    2003-06-01

    We analyze high-resolution foreign exchange data consisting of 20 million data points of USD-JPY for 13 years to report firm statistical laws in distributions and correlations of exchange rate fluctuations. A conditional probability density analysis clearly shows the existence of trend-following movements at time scale of 8-ticks, about 1 min.

  8. Storage and Aging Effects on Spherical Resorcinol-Formaldehyde Resin Ion Exchange Performance

    SciTech Connect

    Fiskum, Sandra K.; Arm, Stuart T.; Edwards, Matthew K.; Steele, Marilyn J.; Thomas, Kathie K.

    2007-09-10

    Bechtel National, Inc. (BNI) is evaluating the alternate Cs ion exchanger, spherical resorcinol-formaldehyde (RF), for use in the River Protection Project-Waste Treatment Plant (RPP-WTP).( ) Previous test activities with spherical RF indicate that it has adequate capacity, selectivity, and kinetics to perform in the plant according to the flowsheet needs. It appears to have better elution and hydraulic properties than the existing alternatives: ground-gel RF and SuperLig® 644 (SL 644).( ) To date, the spherical RF performance testing has been conducted on freshly manufactured resin (within ~2 months of manufacture). The ion exchange resins will be manufactured and shipped to the WTP up to 1 year before being used in the plant. Changes in the resin properties during storage could reduce the capacity of the resin to remove Cs from low-activity waste solutions. Active sites on organic SL-644 resin have been shown to degrade during storage (Arm et al. 2004). Additional testing was needed to study the effects of storage conditions and aging on spherical RF ion exchange performance. Variables that could have a significant impact on ion exchange resins during storage include storage temperature, medium, and time. Battelle—Pacific Northwest Division (PNWD) was contracted to test the effects of various storage conditions on spherical RF resin. Data obtained from the testing will be used by the WTP operations to provide direction for suitable storage conditions and manage the spherical RF resin stock. Storage test conditions included wet and dry resin configurations under nitrogen at three temperatures. Work was initially conducted under contract number 24590-101-TSA-W000-00004 satisfying the needs defined in Appendix C of the Research and Technology Plan( ) TSS A-219 to evaluate the impact of storage conditions on RF resin performance. In February 2007, the contract mechanism was switched to Pacific Northwest National Laboratory (PNNL) Operating Contract DE-AC05-76RL

  9. Experimental performance investigation of a shell and tube heat exchanger by exergy based sensitivity analysis

    NASA Astrophysics Data System (ADS)

    Mert, Suha Orçun; Reis, Alper

    2016-06-01

    Heat exchangers are used extensively in many industrial branches, primarily so in chemical and energy sectors. They also have important household usage as they are used in central and local heating systems. Any betterment on heat exchangers will serve greatly in preserving our already dwindling and costly energy resources. Strong approach of exergy analysis -which helps find out where the first steps should be taken in determining sources of inefficiencies and how to remedy them- will be used as a means to this end. The maximum useful work that can be harnessed from systems relationships with its environment is defined as exergy. In this study, the inlet and outlet flow rate values of fluids and temperature of hot stream both on shell and tube parts of a shell-tube heat exchange system have been inspected and their effects on the exergy efficiency of this thermal system have been analyzed. It is seen that the combination of high tube side inlet temperature, low shell side flow rate and high tube side flow rate are found to be the optimum for this experimental system with reaching 75, 65, and 32 % efficiencies respectively. Selecting operating conditions suitable to this behavior will help to increase the overall efficiency of shell-tube heat exchange systems and cause an increment in energy conservation.

  10. Performance and cost characteristics of multi-electron transfer, common ion exchange non-aqueous redox flow batteries

    NASA Astrophysics Data System (ADS)

    Laramie, Sydney M.; Milshtein, Jarrod D.; Breault, Tanya M.; Brushett, Fikile R.; Thompson, Levi T.

    2016-09-01

    Non-aqueous redox flow batteries (NAqRFBs) have recently received considerable attention as promising high energy density, low cost grid-level energy storage technologies. Despite these attractive features, NAqRFBs are still at an early stage of development and innovative design techniques are necessary to improve performance and decrease costs. In this work, we investigate multi-electron transfer, common ion exchange NAqRFBs. Common ion systems decrease the supporting electrolyte requirement, which subsequently improves active material solubility and decreases electrolyte cost. Voltammetric and electrolytic techniques are used to study the electrochemical performance and chemical compatibility of model redox active materials, iron (II) tris(2,2‧-bipyridine) tetrafluoroborate (Fe(bpy)3(BF4)2) and ferrocenylmethyl dimethyl ethyl ammonium tetrafluoroborate (Fc1N112-BF4). These results help disentangle complex cycling behavior observed in flow cell experiments. Further, a simple techno-economic model demonstrates the cost benefits of employing common ion exchange NAqRFBs, afforded by decreasing the salt and solvent contributions to total chemical cost. This study highlights two new concepts, common ion exchange and multi-electron transfer, for NAqRFBs through a demonstration flow cell employing model active species. In addition, the compatibility analysis developed for asymmetric chemistries can apply to other promising species, including organics, metal coordination complexes (MCCs) and mixed MCC/organic systems, enabling the design of low cost NAqRFBs.