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Sample records for nscl gas cell

  1. Charged particle transport and extraction studies in the NSCL gas cell for stopping radioactive fragments

    International Nuclear Information System (INIS)

    Facina, M.; Bachelet, C.; Block, M.; Bollen, G.; Davies, D.; Folden, C.M.; Guenaut, C.; Huikari, J.; Kwan, E.; Morrissey, D.J.; Pang, G.K.; Prinke, A.; Ringle, R.; Savory, J.; Schury, P.; Schwarz, S.; Sumithrarachchi, C.; Sun, T.

    2008-01-01

    The NSCL gas-stopping station thermalizes high-energy projectile fragments for study in the low energy beam and ion trap (LEBIT) facility. The stopping and extraction of fast beams has been studied extensively and the extracted short-lived ions have been used in a series of mass measurements of exotic nuclei. Particle-in-cell simulations of ion drift in the gas cell have been performed. In the present paper calculation results are presented and compared to experimental data obtained with neutron-deficient and neutron-rich As and Se isotopes recently measured at LEBIT. Good agreement between the theoretical and experimental extraction efficiency was found.

  2. The NSCL cyclotron gas stopper – Entering commissioning

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, S. [National Superconducting Cyclotron Laboratory, East Lansing, MI (United States); Bollen, G. [Department of Physics and Astronomy, Michigan State University, East Lansing, MI (United States); Facility for Rare Isotope Beams, East Lansing, MI (United States); Chouhan, S. [Facility for Rare Isotope Beams, East Lansing, MI (United States); Das, J.J. [National Superconducting Cyclotron Laboratory, East Lansing, MI (United States); Green, M. [Facility for Rare Isotope Beams, East Lansing, MI (United States); Magsig, C. [National Superconducting Cyclotron Laboratory, East Lansing, MI (United States); Morrissey, D.J. [National Superconducting Cyclotron Laboratory, East Lansing, MI (United States); Department of Chemistry, Michigan State University, East Lansing, MI 48824 (United States); Ottarson, J.; Sumithrarachchi, C. [National Superconducting Cyclotron Laboratory, East Lansing, MI (United States); Villari, A.C.C.; Zeller, A. [Facility for Rare Isotope Beams, East Lansing, MI (United States)

    2016-06-01

    Linear gas stopping cells have been used successfully at NSCL to slow down ions produced by projectile fragmentation from the 100 MeV/u to the keV energy range. These ‘stopped beams’ have first been used for low-energy high precision experiments and more recently for NSCLs re-accelerator ReA. A gas-filled reverse cyclotron is currently under construction by the NSCL to complement the existing stopping cells: Due to its extended stopping length, efficient stopping and fast extraction is expected even for light and medium-mass ions, which are difficult to thermalize in linear gas cells. The device is based on a 2.6 T maximum-field cyclotron-type magnet to confine the injected beam while it is slowed down in ≈100 mbar of LN{sub 2}-temperature helium gas. Once thermalized, the beam will be transported to the center of the device by a traveling-wave RF-carpet system, extracted along the symmetry axis with an ion conveyor and miniature RF-carpets, and accelerated to a few tens of keV of energy for delivery to the users. The superconducting magnet has been constructed on a 60 kV platform and energized to its nominal field strength. The magnet’s two cryostats use 3 cryo-refrigerators each and liquid-nitrogen cooled thermal shields to cool the coil pair to superconductivity. This concept, chosen not to have to rely on external liquid helium, has been working well. Measurements of axial and radial field profiles confirm the field calculations. The individual RF-ion guiding components for low-energy ion transport through the device have been tested successfully. The beam stopping chamber with its 0.9 m-diameter RF carpet system and the ion extraction system are being prepared for installation inside the magnet for low-energy ion transport tests.

  3. The cyclotron gas stopper project at the NSCL

    Energy Technology Data Exchange (ETDEWEB)

    Guenaut, C., E-mail: guenaut@nscl.msu.edu; Bollen, G.; Chouhan, S.; Marti, F.; Morrissey, D. J.; Lawton, D.; Ottarson, J.; Pang, G. K.; Schwarz, S.; Sherrill, B. M. [Michigan State University (United States); Wada, M. [RIKEN (Japan); Zeller, A. F. [Michigan State University (United States)

    2006-11-15

    Gas stopping is becoming the method of choice for converting beams of rare isotopes obtained via projectile fragmentation and in-flight separation into low-energy beams. These beams allow ISOL-type experiments, such as mass measurements with traps or laser spectroscopy, to be performed with projectile fragmentation products. Current gas stopper systems for high-energy beams are based on linear gas cells filled with 0.1-1 bar of helium. While already used successfully for experiments, it was found that space charge effects induced by the ionization of the helium atoms during the stopping process pose a limit on the maximum beam rate that can be used. Furthermore, the extraction time of stopped ions from these devices can exceed 100 ms causing substantial decay losses for very short-lived isotopes. To avoid these limitations, a new type of gas stopper is being developed at the NSCL/MSU. The new system is based on a cyclotron-type magnet with a stopping chamber filled with Helium buffer gas at low pressure. RF-guiding techniques are used to extract the ions. The space charge effects are considerably reduced by the large volume and due to a separation between the stopping region and the region of highest ionization. Cyclotron gas stopper systems of different sizes and with different magnetic field strengths and field shapes are presently investigated.

  4. The cyclotron gas stopper project at the NSCL

    International Nuclear Information System (INIS)

    Guenaut, C.; Bollen, G.; Chouhan, S.; Marti, F.; Morrissey, D. J.; Lawton, D.; Ottarson, J.; Pang, G. K.; Schwarz, S.; Sherrill, B. M.; Wada, M.; Zeller, A. F.

    2006-01-01

    Gas stopping is becoming the method of choice for converting beams of rare isotopes obtained via projectile fragmentation and in-flight separation into low-energy beams. These beams allow ISOL-type experiments, such as mass measurements with traps or laser spectroscopy, to be performed with projectile fragmentation products. Current gas stopper systems for high-energy beams are based on linear gas cells filled with 0.1-1 bar of helium. While already used successfully for experiments, it was found that space charge effects induced by the ionization of the helium atoms during the stopping process pose a limit on the maximum beam rate that can be used. Furthermore, the extraction time of stopped ions from these devices can exceed 100 ms causing substantial decay losses for very short-lived isotopes. To avoid these limitations, a new type of gas stopper is being developed at the NSCL/MSU. The new system is based on a cyclotron-type magnet with a stopping chamber filled with Helium buffer gas at low pressure. RF-guiding techniques are used to extract the ions. The space charge effects are considerably reduced by the large volume and due to a separation between the stopping region and the region of highest ionization. Cyclotron gas stopper systems of different sizes and with different magnetic field strengths and field shapes are presently investigated.

  5. Research and development of ion surfing RF carpets for the cyclotron gas stopper at the NSCL

    Energy Technology Data Exchange (ETDEWEB)

    Gehring, A.E. [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87544 (United States); Brodeur, M. [University of Notre Dame, Notre Dame, IN (United States); Bollen, G.; Morrissey, D.J.; Schwarz, S. [National Superconducting Cyclotron Laboratory, Michigan State University, 640 S. Shaw Lane, East Lansing, MI 48824 (United States)

    2016-06-01

    A model device to transport thermal ions in the cyclotron gas stopper, a next-generation beam thermalization device under construction at the National Superconducting Cyclotron Laboratory, is presented. Radioactive ions produced by projectile fragmentation will come to rest at distances as large as 45 cm from the extraction orifice of the cyclotron gas stopper. The thermalized ions will be transported to the exit by RF carpets employing the recently developed “ion surfing” method. A quarter-circle prototype RF carpet was tested with potassium ions, and ion transport velocities as high as 60 m/s were observed over distances greater than 10 cm at a helium buffer gas pressure of 80 mbar. The transport of rubidium ions from an RF carpet to an electrode below was also demonstrated. The results of this study formed the basis of the design of the RF carpets for use in the cyclotron gas stopper.

  6. Fabrication of the superferric cyclotron gas-stopper magnet at NSCL at Michigan state university

    International Nuclear Information System (INIS)

    Chouhan, S S; Bollen, G; DeKamp, J; Green, M A; Magsig, C; Zeller, A F; Lawton, D; Morrissey, D J; Ottarson, J; Schwarz, S

    2014-01-01

    The magnet for the cyclotron gas stopper is a newly designed, large warm-iron superconducting cyclotron sector gradient dipole. The maximum field in the centre (gap = 0.18 m) is 2.7 T. The outer diameter of magnet yoke is 4.0 m, with a pole radius of 1.1 m and B * ρ = 1.8 T m. The fabrication and assembly of the iron return yoke and twelve pole pieces is complete. Separate coils are mounted on the return yokes that have a total mass of about 167 metric tons of iron. This paper illustrates the design and the fabrication process for the cyclotron gas-stopper magnet that is being fabricated at MSU.

  7. Operation of GRETINA at NSCL

    Energy Technology Data Exchange (ETDEWEB)

    Sherrill, Bradley [Michigan State Univ., East Lansing, MI (United States); Gade, Alexandra [Michigan State Univ., East Lansing, MI (United States)

    2017-12-31

    This proposal funded the continued operation of the Gamma‐ray Energy tracking Array GRETINA as a user device at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University. This was a continuation and covered the operation from January 1, 2017 to December 31, 2017. Twenty-three experiments were completed with GRETINA at NSCL. GRETINA was installed at the reaction target position of the high‐resolution, large‐acceptance S800 spectrograph and the program started on October 15, 2017. The campaign capitalized on the opportunities provided by NSCL’s energetic rare isotope beams produced by projectile fragmentation.

  8. The NSCL neutron wall facility

    International Nuclear Information System (INIS)

    Zecher, P.; Galonsky, A.; Kruse, J.

    1995-01-01

    The authors have constructed and installed a large-area, high-efficiency neutron detector at the NSCL. The motivation behind the detector's design was provided by their desire to improve a previous experiment, where they measured the soft-dipole-resonance parameters and ground state n-n correlations in 11 Li, and to perform similar experiments on other neutron-rich halo nuclei. The detector consists of two planes of liquid scintillator, each 4 square meters in area; it is position sensitive and is capable of neutron-γ-ray discrimination. A general overview of the detector's design and measurements of its performance in test experiments will be presented

  9. LEBIT - a low-energy beam and ion trap facility at NSCL/MSU

    International Nuclear Information System (INIS)

    Schwarz, S.; Bollen, G.; Davies, D.; Lawton, D.; Lofy, P.; Morrissey, D. J.; Ottarson, J.; Ringle, R.; Schury, P.; Sun, T.; VanWasshenova, D.; Sun, T.; Weissman, L.; Wiggins, D.

    2003-01-01

    The Low Energy Beam and Ion Trap (LEBIT) Project aims to convert the high-energy exotic beams produced at NSCL/MSU into low-energy low-emittance beams. A combination of a high-pressure gas stopping cell and a radiofrequency quadrupole (RFQ) ion accumulator and buncher will be used to manipulate the beam accordingly. High-accuracy mass measurements on very short-lived isotopes with a 9.4 T Penning trap system will be the first experimental program to profit from the low-energy beams. The status of the project is presented with a focus on recent stopping tests of 100-140 MeV/A Ar18+ ions in a gas cell

  10. The low-energy-beam and ion-trap facility at NSCL/MSU

    CERN Document Server

    Schwarz, S; Lawton, D; Lofy, P; Morrissey, D J; Ottarson, J; Ringle, R; Schury, P; Sun, T; Varentsov, V; Weissman, L

    2003-01-01

    The goal of the low-energy-beam and ion-trap (LEBIT) project is to convert the high-energy exotic beams produced at NSCL/MSU into low-energy low-emittance beams. This beam manipulation will be done by a combination of a high-pressure gas stopping cell and a radio-frequency quadrupole ion accumulator and buncher. The first experimental program to profit from the low-energy beams produced will be high-accuracy mass measurements on very short-lived isotopes with a 9.4 T Penning trap system. The status of the project is presented with an emphasis on recent stopping tests range of 100 MeV/A sup 4 sup 0 Ar sup 1 sup 8 sup + ions in a gas cell.

  11. The low-energy-beam and ion-trap facility at NSCL/MSU

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, S. E-mail: schwarz@nscl.msu.edu; Bollen, G.; Lawton, D.; Lofy, P.; Morrissey, D.J.; Ottarson, J.; Ringle, R.; Schury, P.; Sun, T.; Varentsov, V.; Weissman, L

    2003-05-01

    The goal of the low-energy-beam and ion-trap (LEBIT) project is to convert the high-energy exotic beams produced at NSCL/MSU into low-energy low-emittance beams. This beam manipulation will be done by a combination of a high-pressure gas stopping cell and a radio-frequency quadrupole ion accumulator and buncher. The first experimental program to profit from the low-energy beams produced will be high-accuracy mass measurements on very short-lived isotopes with a 9.4 T Penning trap system. The status of the project is presented with an emphasis on recent stopping tests range of 100 MeV/A {sup 40}Ar{sup 18+} ions in a gas cell.

  12. The low-energy-beam and ion-trap facility at NSCL/MSU

    International Nuclear Information System (INIS)

    Schwarz, S.; Bollen, G.; Lawton, D.; Lofy, P.; Morrissey, D.J.; Ottarson, J.; Ringle, R.; Schury, P.; Sun, T.; Varentsov, V.; Weissman, L.

    2003-01-01

    The goal of the low-energy-beam and ion-trap (LEBIT) project is to convert the high-energy exotic beams produced at NSCL/MSU into low-energy low-emittance beams. This beam manipulation will be done by a combination of a high-pressure gas stopping cell and a radio-frequency quadrupole ion accumulator and buncher. The first experimental program to profit from the low-energy beams produced will be high-accuracy mass measurements on very short-lived isotopes with a 9.4 T Penning trap system. The status of the project is presented with an emphasis on recent stopping tests range of 100 MeV/A 40 Ar 18+ ions in a gas cell

  13. Commissioning results of the ReA EBIT charge breeder at the NSCL: First reacceleration of stable-isotope beams

    Energy Technology Data Exchange (ETDEWEB)

    Lapierre, A., E-mail: lapierre@nscl.msu.edu; Schwarz, S.; Kittimanapun, K.; Rodriguez, J.A.; Sumithrarachchi, C.; Barquest, B.; Berryman, E.; Cooper, K.; Fogleman, J.; Krause, S.; Kwarsick, J.; Nash, S.; Perdikakis, G.; Portillo, M.; Rencsok, R.; Skutt, D.; Steiner, M.; Tobos, L.; Wittmer, W.; Bollen, G.; and others

    2013-12-15

    Highlights: • Latest results with the electron-beam ion trap of the ReA post-accelerator at the NSCL. • First reacceleration of stable-isotope beams. • First injection of stable-isotope beams from the NSCL’s beam stopping vault. -- Abstract: ReA is a reaccelerator of rare-isotope beams at the National Superconducting Cyclotron Laboratory (NSCL). The rare isotopes are produced by fast projectile fragmentation. After production, they are separated in-flight and thermalized in a He gas “catcher” cell before being sent to ReA for reacceleration to a few MeV/u. One of its main components is an electron-beam ion trap (EBIT) employed to convert injected singly charged ions to highly charged ions prior to injection into linear-accelerator structures. The ReA EBIT features a high-current electron gun, a long trap structure, and a two-field superconducting magnet to provide both the high electron-beam current density needed for fast charge breeding and high capture probability of injected beams. This paper presents recent commissioning results. In particular, {sup 39}K{sup +} ions have been injected, charge bred to {sup 39}K{sup 16+} and extracted for reacceleration up to 60 MeV. First charge-breeding results of beams injected from a commissioning Rb ion source in the NSCL’s beam “stopping” vault are also presented.

  14. Radio Frequency Fragment Separator at NSCL

    International Nuclear Information System (INIS)

    Bazin, D.; Andreev, V.; Becerril, A.; Doleans, M.; Mantica, P.F.; Ottarson, J.; Schatz, H.; Stoker, J.B.; Vincent, J.

    2009-01-01

    A new device has been designed and built at NSCL which provides additional filtering of radioactive beams produced via projectile fragmentation. The Radio Frequency Fragment Separator (RFFS) uses the time micro structure of the beams accelerated by the cyclotrons to deflect particles according to their time-of-flight, in effect producing a phase filtering. The transverse RF (Radio Frequency) electric field of the RFFS has superior filtering performance compared to other electrostatic devices, such as Wien filters. Such filtering is critical for radioactive beams produced on the neutron-deficient side of the valley of stability, where strong contamination occurs at intermediate energies from 50 to 200 MeV/u.

  15. Commissioning of the collinear laser spectroscopy system in the BECOLA facility at NSCL

    International Nuclear Information System (INIS)

    Minamisono, K.; Mantica, P.F.; Klose, A.; Vinnikova, S.; Schneider, A.; Johnson, B.; Barquest, B.R.

    2013-01-01

    A collinear laser-spectroscopy (CLS) system in the BEam COoler and LAser spectroscopy (BECOLA) facility was constructed at National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University. The BECOLA facility will be used to advance measurements of nuclear properties of low-energy rare isotope beams generated via in-flight reactions and subsequent beam thermalization in a buffer gas. The CLS studies at BECOLA will complement laser spectroscopy studies of charge radii and nuclear moments mostly obtained so far at Isotope SeOn Line (ISOL) facilities. Commissioning tests of the CLS system have been performed using an offline ion source to produce stable-ion beams. The tests set the ground work for experiments at the future Facility for Rare Isotope Beams (FRIB) as well as experiments at the current Coupled Cyclotron Facility at NSCL

  16. NSCL and FRIB at Michigan State University: Nuclear science at the limits of stability

    Science.gov (United States)

    Gade, A.; Sherrill, B. M.

    2016-05-01

    The National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU) is a scientific user facility that offers beams of rare isotopes at a wide range of energies. This article describes the facility, its capabilities, and some of the experimental devices used to conduct research with rare isotopes. The versatile nuclear science program carried out by researchers at NSCL continues to address the broad challenges of the field, employing sensitive experimental techniques that have been developed and optimized for measurements with rare isotopes produced by in-flight separation. Selected examples showcase the broad program, capabilities, and the relevance for forefront science questions in nuclear physics, addressing, for example, the limits of nuclear existence; the nature of the nuclear force; the origin of the elements in the cosmos; the processes that fuel explosive scenarios in the Universe; and tests for physics beyond the standard model of particle physics. NSCL will cease operations in approximately 2021. The future program will be carried out at the Facility for Rare Isotope Beams, FRIB, presently under construction on the MSU campus adjacent to NSCL. FRIB will provide fast, stopped, and reaccelerated beams of rare isotopes at intensities exceeding NSCL’s capabilities by three orders of magnitude. An outlook will be provided on the enormous opportunities that will arise upon completion of FRIB in the early 2020s.

  17. Radioactive ion beams in the region of 100Sn and 78Ni at the NSCL

    International Nuclear Information System (INIS)

    Stolz, A.; Estrade, A.; Davies, A.D.; Ginter, T.N.; Hosmer, P.T.; Kwan, E.; Liddick, S.N.; Mantica, P.F.; Mertzimekis, T.J.; Montes, F.A.; Morrissey, D.J.; Morton, A.C.; Ouellette, M.; Pellegrini, E.; Santi, P.; Schatz, H.; Steiner, M.; Stuchberry, A.E.; Tomlin, B.E.; Walters, W.B.; Woehr, A.; Arndt, O.; Kratz, K.-L.; Pfeiffer, B.; Reeder, P.

    2004-01-01

    The regions around the doubly magic nuclei 100 Sn and 78 Ni are of great interest from a nuclear structure standpoint. These nuclei also play a key role in the astrophysical rp- and r-processes, respectively. Recently, nuclei in these regions were studied at the Coupled Cyclotron Facility at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University

  18. Gas transport in solid oxide fuel cells

    CERN Document Server

    He, Weidong; Dickerson, James

    2014-01-01

    This book provides a comprehensive overview of contemporary research and emerging measurement technologies associated with gas transport in solid oxide fuel cells. Within these pages, an introduction to the concept of gas diffusion in solid oxide fuel cells is presented. This book also discusses the history and underlying fundamental mechanisms of gas diffusion in solid oxide fuel cells, general theoretical mathematical models for gas diffusion, and traditional and advanced techniques for gas diffusivity measurement.

  19. Gas cell neutralizers (Fundamental principles)

    International Nuclear Information System (INIS)

    Fuehrer, B.

    1985-06-01

    Neutralizing an ion-beam of the size and energy levels involved in the neutral-particle-beam program represents a considerable extension of the state-of-the-art of neutralizer technology. Many different mediums (e.g., solid, liquid, gas, plasma, photons) can be used to strip the hydrogen ion of its extra electron. A large, multidisciplinary R and D effort will no doubt be required to sort out all of the ''pros and cons'' of these various techniques. The purpose of this particular presentation is to discuss some basic configurations and fundamental principles of the gas type of neutralizer cell. Particular emphasis is placed on the ''Gasdynamic Free-Jet'' neutralizer since this configuration has the potential of being much shorter than other type of gas cells (in the beam direction) and it could operate in nearly a continuous mode (CW) if necessary. These were important considerations in the ATSU design which is discussed in some detail in the second presentation entitled ''ATSU Point Design''

  20. A Preliminary Investigation of NSCL/P Plasma and Urine in Guizhou Province in China Using NMR-Based Metabonomics.

    Science.gov (United States)

    Lei, Huang Guang; Hong, Luo; Kun, Song Ju; Hai, Yin Xin; Dong, Wang Ya; Ke, Zhao; Ping, Xu; Hao, Chen

    2013-09-01

    Objective : To assess the feasibility of metabonomics in clinical studies. This is a pilot study introducing nuclear magnetic resonance (NMR)-based metabonomics to elucidate and compare the metabolism of patients with nonsyndromic cleft lip and/or palate (NSCL/P) and children without orofacial clefts. Methods : High-resolution (1)H NMR spectroscopy was performed on plasma and urine samples obtained from NSCL/P and healthy children. The (1)H NMR spectra were further analyzed with principal component analysis. Results : Compared to the control group, the level of low-molecular-weight metabolites in plasma such as asparagine was higher in NSCL/P patients, while arginine, lysine, acetate, lactate, proline, glutamine, pyruvate, creatinine, choline, and β-glucose were lower. The carnitine, citrate, and formate excretion in urine appeared to be higher in the healthy children, while the NSCL/P group excreted higher concentrations of aspartic acid and phenylalanine in urine. Conclusion : The present study clearly demonstrated the great potential of NMR-based metabonomics in elucidating NSCL/P plasma metabolism and the possible application of this technology in clinical diagnosis and screening.

  1. Recoil Distance Method lifetime measurements via gamma-ray and charged-particle spectroscopy at NSCL

    Science.gov (United States)

    Voss, Philip Jonathan

    The Recoil Distance Method (RDM) is a well-established technique for measuring lifetimes of electromagnetic transitions. Transition matrix elements derived from the lifetimes provide valuable insight into nuclear structure. Recent RDM investigations at NSCL present a powerful new model-independent tool for the spectroscopy of nuclei with extreme proton-to-neutron ratios that exhibit surprising behavior. Neutron-rich 18C is one such example, where a small B(E2; 2+1 → 0+gs) represented a dramatic shift from the expected inverse relationship between the B(E2) and 2+1 excitation energy. To shed light on the nature of this quadrupole excitation, the RDM lifetime technique was applied with the Koln/NSCL plunger. States in 18C were populated by the one-proton knockout reaction of a 19N secondary beam. De-excitation gamma rays were detected with the Segmented Germanium Array in coincidence with reaction residues at the focal plane of the S800 Magnetic Spectrometer. The deduced B(E2) and excitation energy were both well described by ab initio no-core shell model calculations. In addition, a novel extension of RDM lifetime measurements via charged-particle spectroscopy of exotic proton emitters has been investigated. Substituting the reaction residue degrader of the Koln/NSCL plunger with a thin silicon detector permits the study of short-lived nuclei beyond the proton dripline. A proof of concept measurement of the mean lifetime of the two-proton emitter 19Mg was conducted. The results indicated a sub-picosecond lifetime, one order of magnitude smaller than the published results, and validate this new technique for lifetime measurements of charged-particle emitters.

  2. Gas recombination assembly for electrochemical cells

    Science.gov (United States)

    Levy, Isaac; Charkey, Allen

    1989-01-01

    An assembly for recombining gases generated in electrochemical cells wherein a catalyst strip is enveloped within a hydrophobic, gas-porous film which, in turn, is encased between gas-porous, metallic layers. The sandwich construction of metallic layers and film is formed into a spiral with a tab for connection to the cell.

  3. Operating a fuel cell using landfill gas

    Energy Technology Data Exchange (ETDEWEB)

    Trippel, C.E.; Preston, J.L. Jr.; Trocciola, J.; Spiegel, R.

    1996-12-31

    An ONSI PC25{trademark}, 200 kW (nominal capacity) phosphoric acid fuel cell operating on landfill gas is installed at the Town of Groton Flanders Road landfill in Groton, Connecticut. This joint project by the Connecticut Light & Power Company (CL&P) which is an operating company of Northeast Utilities, the Town of Groton, International Fuel Cells (IFC), and the US EPA is intended to demonstrate the viability of installing, operating and maintaining a fuel cell operating on landfill gas at a landfill site. The goals of the project are to evaluate the fuel cell and gas pretreatment unit operation, test modifications to simplify the GPU design and demonstrate reliability of the entire system.

  4. Design and commissioning of a 16.1 MHz multiharmonic buncher for the reaccelerator at NSCL

    Science.gov (United States)

    Alt, Daniel Maloney

    The ReAccelerator (ReA) linear accelerator facility at the National Superconducting Cyclotron Laboratory is a unique resource for the nuclear physics community. The particle fragmentation beam production technique, combined with the ability to stop and then reaccelerate the beam to energies of astrophysical interest, give experimenters an unprecedented range of rare isotopes at energies of nuclear and astrophysical interest. The ReAccelerator also functions as a testbed for technology to be incorporated in the upcoming Facility for Rare Isotope Beams linear accelerator, which will eventually in turn become the beam source for ReA. This prototype nature of the ReAccelerator, however, dictated some design choices which have resulted in a final beam with a time structure that is less than ideal for certain classes of experiments. The cavities and RFQ used in ReA have an operating frequency of 80.5 MHz, which corresponds to a separation between particle bunches at the detectors of 12.4 ns. While this separation is acceptable for many experiments, sensitive time of flight measurements require a greater separation between pulses. As nuclear physics experiments rely on statistics, a solution to increasing bunch separation without simply discarding a large fraction of the beam particles was desired. This document describes the design and construction of such a device, a 16.1 MHz multiharmonic buncher. The first chapter provides backgound information on the NSCL and ReA, and some basic concepts in accelerator physics to lay the groundwork for the project.Next, more specifics are provided on the time structure of accelerated beams, and the experimental motivation for greater separation. The third chapter outlines the basic principles of multiharmonic bunching. In order to evaluate the feasibility of any buncher design, the exact acceptance of the Radiofrequency Quadrupole (RFQ) of the ReAccelerator needed to be empirically measured. Chapter 4 describes the results of that

  5. Association of common variants in PAH and LAT1 with non-syndromic cleft lip with or without cleft palate (NSCL/P) in the Polish population.

    Science.gov (United States)

    Hozyasz, Kamil K; Mostowska, Adrianna; Wójcicki, Piotr; Lasota, Agnieszka; Wołkowicz, Anna; Dunin-Wilczyńska, Izabella; Jagodziński, Paweł P

    2014-04-01

    Non-syndromic cleft lip with or without cleft palate (NSCL/P) is a common structural malformation with a complex and multifactorial aetiology. Associations of abnormalities in phenylalanine metabolism and orofacial clefts have been suggested. Eight single nucleotide polymorphisms (SNPs) of genes encoding phenylalanine hydroxylase (PAH) and large neutral l-amino acid transporter type 1 (LAT1), as well as the PAH mutation that is most common in the Polish population (rs5030858; R408W), were investigated in 263 patients with NSCL/P and 270 matched controls using high resolution melting curve analysis (HRM). We found that two polymorphic variants of PAH appear to be risk factors for NSCL/P. The odds ratio (OR) for individuals with the rs7485331 A allele (AC or AA) compared to CC homozygotes was 0.616 (95% confidence interval [CI]=0.437-0.868; p=0.005) and this association remains statistically significant after multiple testing correction. The PAH rs12425434, previously associated with schizophrenia, was borderline associated with orofacial clefts. Moreover, haplotype analysis of polymorphisms in the PAH gene revealed a 4-marker combination that was significantly associated with NSCL/P. The global p-value for a haplotype comprised of SNPs rs74385331, rs12425434, rs1722392, and the mutation rs5030858 was 0.032, but this association did not survive multiple testing correction. This study suggests the involvement of the PAH gene in the aetiology of NSCL/P in the tested population. Further replication will be required in separate cohorts to confirm the consistency of the observed association. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Constraining the rp-process by measuring 23Al(d,n24Si with GRETINA and LENDA at NSCL

    Directory of Open Access Journals (Sweden)

    Wolf Clemens

    2017-01-01

    In this proceeding we will present a new experimental study to investigate this reaction, using the surrogate reaction 23Al(d,n at 47 AMeV at the National Superconducting Cyclotron Laboratory (NSCL. We will discuss our new experimental setup which allows us to use full kinematics employing the Gamma-Ray Energy Tracking In-beam Nuclear Array (GRETINA to detect the γ-rays following the de-excitation of excited states of the reaction products and the Low Energy Neutron Detector Array (LENDA to detect the recoiling neutrons. The S800 was used for identification of the 24Si recoils. As a proof of principle to show the feasibility of this concept the Q-value spectrum of 22Mg(d,n23Al is reconstructed.

  7. Gas injection system in the Tara center cell

    International Nuclear Information System (INIS)

    Brau, K.; Post, R.S.; Sevillano, E.

    1985-11-01

    Precise control of the gas fueling is essential to the successful operation of tandem mirror plasmas. Improper choice of fueling location, magnetic geometry, and gas injection rates can prevent potential and thermal barrier formation, as well as reduce the energy confinement time. In designing the new gas injection configuration for the Tara center cell, the following issues were addressed: RF potential barriers, gas leakage, and charge exchange recombination. 2 refs., 6 figs

  8. Gas replacement system for fuel cell. Nenryo denchi no gas chikan hoshiki

    Energy Technology Data Exchange (ETDEWEB)

    Sugiyama, T

    1990-02-14

    When stopping the operation of a fuel cell, the gas in the reaction gas system is purged using such an inert gas as nitrogen for inactivation. A gas source such as inert gas bomb must be prepared beforehand for the purpose. This invention relates to a method of production of inert gas from the air collected from atmosphere to use it as the purge gas. The air collected from the atmosphere is passed through an oxygen remover filled with oxidation catalyst to remove oxygen, and dehumidified by a dehumidifier filled with drying agent, the obtained inert drying gas with nitrogen as the main constituent being used as the purge gas. Copper system catalyst supported by silica is used as the oxidation catalyst, and silica gel as the drying agent. After the operation of the fuel cell is re-started, a part of the high temperature fuel gas extracted from the reaction gas system is introduced to the oxygen remover for the reduction of oxidation catalyst and for heat regeneration of dehumidifying agent by the contained hydrogen. 1 fig.

  9. A Miniaturized Optical Sensor with Integrated Gas Cell

    NARCIS (Netherlands)

    Ayerden, N.P.; Ghaderi, M.; De Graaf, G.; Wolffenbuttel, R.F.

    2015-01-01

    The design, fabrication and characterization of a highly integrated optical gas sensor is presented. The gas cell takes up most of the space in a microspectrometer and is the only component that has so far not been miniaturized. Using the tapered resonator cavity of a linear variable optical filter

  10. Investigations of Laser Pumped Gas Cell Atomic Frequency Standard

    National Research Council Canada - National Science Library

    Volk, C. H; Camparo, J. C; Frueholz, R. P

    1981-01-01

    Recently it has been suggested that the performance characteristics of a rubidium gas cell atomic frequency standard might be improved by replacing the standard rubidium discharge lamp with a single mode laser diode...

  11. Hot gas flow cell for optical measurements on reactive gases

    DEFF Research Database (Denmark)

    Grosch, Helge; Fateev, Alexander; Nielsen, Karsten Lindorff

    2013-01-01

    A new design is presented for a gas flow cell for reactive gases at high temperatures. The design features three heated sections that are separated by flow windows. This design avoids the contact of reactive gases with the material of the exchangeable optical windows. A gas cell with this design ......-resolution measurements are presented for the absorption cross-section of sulfur dioxide (SO2) in the UV range up to 773 K (500 degrees C)...

  12. Targeting Gas6/TAM in cancer cells and tumor microenvironment.

    Science.gov (United States)

    Wu, Guiling; Ma, Zhiqiang; Cheng, Yicheng; Hu, Wei; Deng, Chao; Jiang, Shuai; Li, Tian; Chen, Fulin; Yang, Yang

    2018-01-31

    Growth arrest-specific 6, also known as Gas6, is a human gene encoding the Gas6 protein, which was originally found to be upregulated in growth-arrested fibroblasts. Gas6 is a member of the vitamin K-dependent family of proteins expressed in many human tissues and regulates several biological processes in cells, including proliferation, survival and migration, by binding to its receptors Tyro3, Axl and Mer (TAM). In recent years, the roles of Gas6/TAM signalling in cancer cells and the tumour microenvironment have been studied, and some progress has made in targeted therapy, providing new potential directions for future investigations of cancer treatment. In this review, we introduce the Gas6 and TAM receptors and describe their involvement in different cancers and discuss the roles of Gas6 in cancer cells, the tumour microenvironment and metastasis. Finally, we introduce recent studies on Gas6/TAM targeting in cancer therapy, which will assist in the experimental design of future analyses and increase the potential use of Gas6 as a therapeutic target for cancer.

  13. Foam Based Gas Diffusion Electrodes for Reversible Alkaline Electrolysis Cells

    DEFF Research Database (Denmark)

    Allebrod, Frank; Chatzichristodoulou, Christodoulos; Mogensen, Mogens Bjerg

    2014-01-01

    Alkaline electrolysis cells operated at 250 °C and 40 bar have shown to be able to convert electrical energy into hydrogen at very high efficiencies and power densities. Foam based gas diffusion electrodes and an immobilized electrolyte allow for reversible operation as electrolysis cell or fuel...... cell. In the present work we demonstrate the application of hydrophobic, porous, and electro-catalytically active gas diffusion electrodes. PTFE particles and silver nanowires as electro-catalysts were used in the gas diffusion electrodes. Impedance spectroscopy and cyclic voltammetry were performed...... to determine the cell characteristics. The thickness of the electrolyte matrix was only 200 µm, thereby achieving a serial resistance and area specific resistance of 60 mΩ cm2 and 150 mΩ cm2, respectively, at 200 °C and 20 bar. A new production method was developed to increase the cell size from lab scale (1...

  14. Constraining the rp-process by measuring 23Al(d,n)24Si with GRETINA and LENDA at NSCL

    Science.gov (United States)

    Wolf, Clemens; Langer, Christoph; Montes, Fernando; Pereira, Jorge; Ahn, Sunghoon; Ayoub, Sara; Bazin, Daniel; Bender, Peter; Brown, Alex; Browne, Justin; Crawford, Heather; Deleeuw, Eric; Elman, Brandon; Fiebiger, Stefan; Gade, Alexandra; Gastis, Panagiotis; Lipschutz, Samuel; Longfellow, Brenden; Nunes, Filomena; Ong, Wei-Jia; Poxon-Pearson, Terri; Perdikakis, Georgios; Reifarth, René; Schatz, Hendrik; Schmidt, Konrad; Schmitt, Jaclyn; Sullivan, Chris; Titus, Rachel; Weisshaar, Dirk; Woods, Philip; Zamora, Juan Carlos; G. T. Zegers, Remco

    2018-01-01

    The 23Al(p, γ)24Si stellar reaction rate has a significant impact on the light-curve emitted in X-ray bursts. Theoretical calculations show that the reaction rate is mainly determined by the properties of direct capture as well as low-lying 2+ states and a possible 4+ state in 24Si. Currently, there is little experimental information on the properties of these states. In this proceeding we will present a new experimental study to investigate this reaction, using the surrogate reaction 23Al(d,n) at 47 AMeV at the National Superconducting Cyclotron Laboratory (NSCL). We will discuss our new experimental setup which allows us to use full kinematics employing the Gamma-Ray Energy Tracking In-beam Nuclear Array (GRETINA) to detect the γ-rays following the de-excitation of excited states of the reaction products and the Low Energy Neutron Detector Array (LENDA) to detect the recoiling neutrons. The S800 was used for identification of the 24Si recoils. As a proof of principle to show the feasibility of this concept the Q-value spectrum of 22Mg(d,n)23Al is reconstructed.

  15. Method and system for purification of gas/liquid streams for fuel cells or electrolysis cells

    DEFF Research Database (Denmark)

    2013-01-01

    at least one scrubber in the gas/liquid stream at the inlet side of the first electrode of the fuel cell or electrolysis cell; and/or providing at least one scrubber in the gas/liquid stream at the inlet side of the second electrode of the fuel cell or electrolysis cell; and - purifying the gas....../liquid streams towards the first and second electrode; wherein the at least one scrubber in the gas/liquid stream at the inlet side of the first electrode and/or the at least one scrubber in the gas/liquid stream at the inlet side of the second electrode comprises a material suitable as an electrolyte material...... with the at least one scrubber, with the proviso that the fuel cell or electrolysis cell is not a solid oxide cell....

  16. Miniature fuel cells relieve gas pressure in sealed batteries

    Science.gov (United States)

    Frank, H. A.

    1971-01-01

    Miniature fuel cells within sealed silver zinc batteries consume evolved hydrogen and oxygen rapidly, preventing pressure rupturing. They do not significantly increase battery weight and they operate in all battery life phases. Complete gas pressure control requires two fuel cells during all phases of operation of silver zinc batteries.

  17. Foam Based Gas Diffusion Electrodes for Reversible Alkaline Electrolysis Cells

    DEFF Research Database (Denmark)

    Allebrod, Frank; Chatzichristodoulou, Christodoulos; Mogensen, Mogens Bjerg

    2014-01-01

    Alkaline electrolysis cells operated at 250 °C and 40 bar have shown to be able to convert electrical energy into chemical energy in the form of hydrogen at very high efficiencies and power densities. Foam based gas diffusion electrodes and a liquid immobilized electrolyte allow the operation...... of the newly designed electrolysis cell as a fuel cell, but condensation of steam may lead to blocked pores, thereby inhibiting gas diffusion and decreasing the performance of the cell. In the here presented work we present the application of a hydrophobic, porous, and electro-catalytically active layer...... the electrochemical characteristics of the cell. The thickness of the electrolyte matrix was reduced to 200 µm, thereby achieving a serial resistance and area specific resistance as low as 60 mΩ cm2 and 150 mΩ cm2, respectively, at a temperature of 200 °C and 20 bar pressure. A new production method was developed...

  18. The Innovative Design of Lucas Cell for Radon Gas Measurement

    International Nuclear Information System (INIS)

    Wanabongse, Paitoon; Rattanabussayaporn, Sakon; Sriya, Maitree; Sola, Banthom

    2007-08-01

    Full text: Lucas scintillation cell has been widely used for radon gas measurement. They are commercially available but usually with a rather high price, therefore, four cells were developed and built in house. The invented radon gas detector has a special feature; the circumference of the upper part of the cylindrical detector is larger than the lower part. The purpose of this is to allow the light sensing device coupled at the lower end can better detect the phosphorescence light occurred inside. The result is that the invented detector yields higher detection efficiency. This special feature also allows us to increase the volume of the detector which results in higher detection sensitivity

  19. A gas circulation and purification system for gas-cell-based low-energy RI-beam production

    Energy Technology Data Exchange (ETDEWEB)

    Sonoda, T.; Wada, M.; Katayama, I.; Kojima, T. M.; Reponen, M. [RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Tsubota, T. [Tokyo KOATSU Co., Ltd., 1-9-8 Shibuya, Shibuyaku, Tokyo 150-0002 (Japan)

    2016-06-15

    A gas circulation and purification system was developed at the RIKEN Radioactive Isotope Beam Factory that can be used for gas-cell-based low-energy RI-beam production. A high-flow-rate gas cell filled with one atmosphere of buffer gas (argon or helium) is used for the deceleration and thermalization of high-energy RI-beams. The exhausted buffer gas is efficiently collected using a compact dry pump and returned to the gas cell with a recovery efficiency of >97%. The buffer gas is efficiently purified using two gas purifiers as well as collision cleaning, which eliminates impurities in the gas. An impurity level of one part per billion is achieved with this method.

  20. Test results for fuel cell operation on anaerobic digester gas

    Science.gov (United States)

    Spiegel, R. J.; Preston, J. L.

    EPA, in conjunction with ONSI, embarked on a project to define, design, test, and assess a fuel cell energy recovery system for application at anaerobic digester waste water (sewage) treatment plants. Anaerobic digester gas (ADG) is produced at these plants during the process of treating sewage anaerobically to reduce solids. ADG is primarily comprised of methane (57-66%), carbon dioxide (33-39%), nitrogen (1-10%), and a small amount of oxygen (sulfur-bearing compounds (principally hydrogen sulfide) and halogen compounds (chlorides). The project has addressed two major issues: development of a cleanup system to remove fuel cell contaminants from the gas and testing/assessing of a modified ONSI PC25 C fuel cell power plant operating on the cleaned, but dilute, ADG. Results to date demonstrate that the ADG fuel cell power plant can, depending on the energy content of the gas, produce electrical output levels close to full power (200 kW) with measured air emissions comparable to those obtained by a natural gas fuel cell. The cleanup system results show that the hydrogen sulfide levels are reduced to below 10 ppbv and halides to approximately 30 ppbv.

  1. Flexible fuel cell gas manifold system

    Science.gov (United States)

    Cramer, Michael; Shah, Jagdish; Hayes, Richard P.; Kelley, Dana A.

    2005-05-03

    A fuel cell stack manifold system in which a flexible manifold body includes a pan having a central area, sidewall extending outward from the periphery of the central area, and at least one compound fold comprising a central area fold connecting adjacent portions of the central area and extending between opposite sides of the central area, and a sidewall fold connecting adjacent portions of the sidewall. The manifold system further includes a rail assembly for attachment to the manifold body and adapted to receive pins by which dielectric insulators are joined to the manifold assembly.

  2. Indirect-fired gas turbine bottomed with fuel cell

    Science.gov (United States)

    Micheli, P.L.; Williams, M.C.; Parsons, E.L.

    1995-09-12

    An indirect-heated gas turbine cycle is bottomed with a fuel cell cycle with the heated air discharged from the gas turbine being directly utilized at the cathode of the fuel cell for the electricity-producing electrochemical reaction occurring within the fuel cell. The hot cathode recycle gases provide a substantial portion of the heat required for the indirect heating of the compressed air used in the gas turbine cycle. A separate combustor provides the balance of the heat needed for the indirect heating of the compressed air used in the gas turbine cycle. Hot gases from the fuel cell are used in the combustor to reduce both the fuel requirements of the combustor and the NOx emissions therefrom. Residual heat remaining in the air-heating gases after completing the heating thereof is used in a steam turbine cycle or in an absorption refrigeration cycle. Some of the hot gases from the cathode can be diverted from the air-heating function and used in the absorption refrigeration cycle or in the steam cycle for steam generating purposes. 1 fig.

  3. A large multi-cell threshold gas Cerenkov counter

    International Nuclear Information System (INIS)

    Declais, Y.; Aubert, J.J.; Bassompierre, G.; Payre, P.; Thenard, J.M.; Urban, L.

    1980-08-01

    A large multi-cell threshold gas Cerenkov counter consisting of 78 cells has been built for use in a high energy muon scattering experiment at CERN (European Muon Collaboration). It is used with neon, nitrogen or a mixture of those two gases, allowing the pion threshold to be varied between 6 and 20 GeV/c. The sensitive region of the counter has a length of 4.0 m and entrance and exit windows of 1.1 x 2.4 m 2 and 2.4 x 5.0 m 2 , respectively

  4. Commercialization of residential fuel cell systems at Tokyo Gas

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Hisao; Kameyama, Hiromichi; Okamura, Kiyoshi; Nishizaki, Kunihiro

    2007-07-01

    Increased affluence at homes may inevitably bring about increased energy consumption with it and hence increased CO2 emission from the residential sector, which accounts for a substantial share in the overall CO2 emission. Technologies that can reduce CO2 emission without sacrificing comfort of living at home will be critically important to achieve economic prosperity and preservation of the global environment at the same time. The residential fuel cell system is one of those technologies. Tokyo Gas has been engaging in its development cooperating with the manufacturers and has been playing an important role in the design, development and promotion of fuel cell systems with its vast knowledge and experience of end users' energy consumption. The development, demonstration and promotion of fuel cell systems have been strongly supported by the Japanese Government. In 'the Large Scale Demonstration Project', more than 1000 units of polymer electrolyte fuel cells have been installed to existing homes and have demonstrated their energy saving and CO2 emission reduction potential. This paper reports the status of the development of residential fuel cell systems in Japan and the role Tokyo Gas plays in it.

  5. Air Contamination Quantification by FTIR with Gas Cell

    Science.gov (United States)

    Freischlag, Jason

    2017-01-01

    Air quality is of utmost importance in environmental studies and has many industrial applications such as aviators grade breathing oxygen (ABO) for pilots and breathing air for fire fighters. Contamination is a major concern for these industries as identified in MIL-PRF-27210, CGA G-4.3, CGA G-7.1, and NFPA 1989. Fourier Transform Infrared Spectroscopy (FTIR) is a powerful tool that when combined with a gas cell has tremendous potential for gas contamination analysis. Current procedures focus mostly on GC-MS for contamination quantification. Introduction of this topic will be done through a comparison of the currently used deterministic methods for gas contamination with those of FTIR gas analysis. Certification of the mentioned standards through the ISOIEC 17065 certifying body A2LA will be addressed followed by an evaluation of quality information such as the determinations of linearity and the limits of detection and quantitation. Major interferences and issues arising from the use of the FTIR for accredited work with ABO and breathing air will be covered.

  6. GAS5 modulated autophagy is a mechanism modulating cisplatin sensitivity in NSCLC cells.

    Science.gov (United States)

    Zhang, N; Yang, G-Q; Shao, X-M; Wei, L

    2016-06-01

    In this study, we investigated the association between lncRNA GAS5 and cisplatin (DDP) resistance in NSCLC and further studied the regulative effect of GAS5 on autophagy and DDP resistance. GAS5 expression in cancerous and adjacent normal tissues from 15 NSCLC patients received neoadjuvant chemotherapy and the following surgery were measured using qRT-PCR analysis. GAS5 gain-and-loss study was performed using A549 and A549/DDP cells as an in-vitro model to investigate the effect of GAS5 on autophagy and cisplatin sensitivity. NSCLC tissues had a substantially lower expression of GAS5 than adjacent normal tissues. The NSCLC tissues from patients with progressive disease (PD) had even lower GAS5 expression. GAS5 knockdown increased DDP IC50 of A549 cells, while GAS5 overexpression decreased DDP IC50 of A549/DDP cells. A549/DDP cells had significantly higher basal autophagy than A549 cells. GAS5 knockdown resulted in decreased autophagy in A549 cells, while GAS5 overexpression led to increased autophagy in A549/DDP cells. Treatment with 3-MA, an autophagy inhibitor, significantly decreased DDP IC50 and promoted DDP-induced cell apoptosis in A549 cells. In addition, 3-MA also partly reversed the effect of GAS5 knockdown. In A549/DDP cells, GAS5 showed the similar effect as 3-MA in reducing DPP IC50 and promoting DDP-induced apoptosis and also presented synergic effect with 3-MA. GAS5 downregulation is associated with cisplatin resistance in NSCLC. GAS5 can inhibit autophagy and therefore enhance cisplatin sensitivity in NSCLC cells.

  7. Cell culture chamber with gas supply for prolonged recording of human neuronal cells on microelectrode array.

    Science.gov (United States)

    Kreutzer, Joose; Ylä-Outinen, Laura; Mäki, Antti-Juhana; Ristola, Mervi; Narkilahti, Susanna; Kallio, Pasi

    2017-03-15

    Typically, live cell analyses are performed outside an incubator in an ambient air, where the lack of sufficient CO 2 supply results in a fast change of pH and the high evaporation causes concentration drifts in the culture medium. That limits the experiment time for tens of minutes. In many applications, e.g. in neurotoxicity studies, a prolonged measurement of extracellular activity is, however, essential. We demonstrate a simple cell culture chamber that enables stable culture conditions during prolonged extracellular recordings on a microelectrode array (MEA) outside an incubator. The proposed chamber consists of a gas permeable silicone structure that enables gas transfer into the chamber. We show that the culture chamber supports the growth of the human embryonic stem cell (hESC)-derived neurons both inside and outside an incubator. The structure provides very low evaporation, stable pH and osmolarity, and maintains strong signaling of hESC-derived neuronal networks over three-day MEA experiments. Existing systems are typically complex including continuous perfusion of medium or relatively large amount of gas to supply. The proposed chamber requires only a supply of very low flow rate (1.5ml/min) of non-humidified 5% CO 2 gas. Utilizing dry gas supply makes the proposed chamber simple to use. Using the proposed culture structure on top of MEA, we can maintain hESC-derived neural networks over three days outside an incubator. Technically, the structure requires very low flow rate of dry gas supporting, however, low evaporation and maintaining the pH of the culture. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Towards a Biohybrid Lung: Endothelial Cells Promote Oxygen Transfer through Gas Permeable Membranes.

    Science.gov (United States)

    Menzel, Sarah; Finocchiaro, Nicole; Donay, Christine; Thiebes, Anja Lena; Hesselmann, Felix; Arens, Jutta; Djeljadini, Suzana; Wessling, Matthias; Schmitz-Rode, Thomas; Jockenhoevel, Stefan; Cornelissen, Christian Gabriel

    2017-01-01

    In patients with respiratory failure, extracorporeal lung support can ensure the vital gas exchange via gas permeable membranes but its application is restricted by limited long-term stability and hemocompatibility of the gas permeable membranes, which are in contact with the blood. Endothelial cells lining these membranes promise physiological hemocompatibility and should enable prolonged application. However, the endothelial cells increase the diffusion barrier of the blood-gas interface and thus affect gas transfer. In this study, we evaluated how the endothelial cells affect the gas exchange to optimize performance while maintaining an integral cell layer. Human umbilical vein endothelial cells were seeded on gas permeable cell culture membranes and cultivated in a custom-made bioreactor. Oxygen transfer rates of blank and endothelialized membranes in endothelial culture medium were determined. Cell morphology was assessed by microscopy and immunohistochemistry. Both setups provided oxygenation of the test fluid featuring small standard deviations of the measurements. Throughout the measuring range, the endothelial cells seem to promote gas transfer to a certain extent exceeding the blank membranes gas transfer performance by up to 120%. Although the underlying principles hereof still need to be clarified, the results represent a significant step towards the development of a biohybrid lung.

  9. A combined gas cooled nuclear reactor and fuel cell cycle

    Science.gov (United States)

    Palmer, David J.

    Rising oil costs, global warming, national security concerns, economic concerns and escalating energy demands are forcing the engineering communities to explore methods to address these concerns. It is the intention of this thesis to offer a proposal for a novel design of a combined cycle, an advanced nuclear helium reactor/solid oxide fuel cell (SOFC) plant that will help to mitigate some of the above concerns. Moreover, the adoption of this proposal may help to reinvigorate the Nuclear Power industry while providing a practical method to foster the development of a hydrogen economy. Specifically, this thesis concentrates on the importance of the U.S. Nuclear Navy adopting this novel design for its nuclear electric vessels of the future with discussion on efficiency and thermodynamic performance characteristics related to the combined cycle. Thus, the goals and objectives are to develop an innovative combined cycle that provides a solution to the stated concerns and show that it provides superior performance. In order to show performance, it is necessary to develop a rigorous thermodynamic model and computer program to analyze the SOFC in relation with the overall cycle. A large increase in efficiency over the conventional pressurized water reactor cycle is realized. Both sides of the cycle achieve higher efficiencies at partial loads which is extremely important as most naval vessels operate at partial loads as well as the fact that traditional gas turbines operating alone have poor performance at reduced speeds. Furthermore, each side of the cycle provides important benefits to the other side. The high temperature exhaust from the overall exothermic reaction of the fuel cell provides heat for the reheater allowing for an overall increase in power on the nuclear side of the cycle. Likewise, the high temperature helium exiting the nuclear reactor provides a controllable method to stabilize the fuel cell at an optimal temperature band even during transients helping

  10. Comparison of gas membrane separation cascades using conventional separation cell and two-unit separation cells

    International Nuclear Information System (INIS)

    Ohno, Masayoshi; Morisue, Tetsuo; Ozaki, Osamu; Miyauchi, Terukatsu.

    1978-01-01

    The adoption of two-unit separation cells in radioactive rare gas membrane separation equipment enhances the separation factor, but increases the required membrane area and compressive power. An analytical economic evaluation was undertaken to compare the conventional separation cell with the two-unit separation cells, adopting as parameters the number of cascade stages, the membrane area and the operating power requirements. This paper describes the models used for evaluating the separation performance and the economics of cascade embodying these different concepts of separation cell taken up for study, and the results obtained for the individual concepts are mutually compared. It proved that, in respect of the number required of cascade stages, of operating power requirements and of the annual expenditure, better performance could always be expected of the two-unit separation cells as compared with the conventional separation cell, at least in the range of parameters adopted in this study. As regards the minimum membrane area, the conventional separation cell and the series-type separation cell yielded almost the same values, with the parallel-type separation cell falling somewhat behind. (auth.)

  11. Diffusivity measurements in some organic solvents by a gas-liquid diaphragm cell

    NARCIS (Netherlands)

    Littel, R.J.; Littel, R.J.; Versteeg, Geert; van Swaaij, Willibrordus Petrus Maria

    1992-01-01

    A diaphragm cell has been developed for the measurement of diffusion coefficients of gases In liquids. The diaphragm cell is operated batchwise with respect to both gas and liquid phases, and the diffusion process Is followed by means of the gas pressure decrease which is recorded by means of a

  12. Diffusivity Measurements in Some Organic Solvents by a Gas-Liquid Diaphragm Cell

    NARCIS (Netherlands)

    Littel, Rob J.; Versteeg, Geert F.; Swaaij, Wim P.M. van

    1992-01-01

    A diaphragm cell has been developed for the measurement of diffusion coefficients of gases in liquids. The diaphragm cell is operated batchwise with respect to both gas and liquid phases, and the diffusion process is followed by means of the gas pressure decrease which is recorded by means of a

  13. Online gas composition estimation in solid oxide fuel cell systems with anode off-gas recycle configuration

    Science.gov (United States)

    Dolenc, B.; Vrečko, D.; Juričić, Ð.; Pohjoranta, A.; Pianese, C.

    2017-03-01

    Degradation and poisoning of solid oxide fuel cell (SOFC) stacks are continuously shortening the lifespan of SOFC systems. Poisoning mechanisms, such as carbon deposition, form a coating layer, hence rapidly decreasing the efficiency of the fuel cells. Gas composition of inlet gases is known to have great impact on the rate of coke formation. Therefore, monitoring of these variables can be of great benefit for overall management of SOFCs. Although measuring the gas composition of the gas stream is feasible, it is too costly for commercial applications. This paper proposes three distinct approaches for the design of gas composition estimators of an SOFC system in anode off-gas recycle configuration which are (i.) accurate, and (ii.) easy to implement on a programmable logic controller. Firstly, a classical approach is briefly revisited and problems related to implementation complexity are discussed. Secondly, the model is simplified and adapted for easy implementation. Further, an alternative data-driven approach for gas composition estimation is developed. Finally, a hybrid estimator employing experimental data and 1st-principles is proposed. Despite the structural simplicity of the estimators, the experimental validation shows a high precision for all of the approaches. Experimental validation is performed on a 10 kW SOFC system.

  14. Estimation of current density distribution of PAFC by analysis of cell exhaust gas

    Energy Technology Data Exchange (ETDEWEB)

    Kato, S.; Seya, A. [Fuji Electric Co., Ltd., Ichihara-shi (Japan); Asano, A. [Fuji Electric Corporate, Ltd., Yokosuka-shi (Japan)

    1996-12-31

    To estimate distributions of Current densities, voltages, gas concentrations, etc., in phosphoric acid fuel cell (PAFC) stacks, is very important for getting fuel cells with higher quality. In this work, we leave developed a numerical simulation tool to map out the distribution in a PAFC stack. And especially to Study Current density distribution in the reaction area of the cell, we analyzed gas composition in several positions inside a gas outlet manifold of the PAFC stack. Comparing these measured data with calculated data, the current density distribution in a cell plane calculated by the simulation, was certified.

  15. Hydrogen generation from natural gas for the fuel cell systems of tomorrow

    Science.gov (United States)

    Dicks, Andrew L.

    In most cases hydrogen is the preferred fuel for use in the present generation of fuel cells being developed for commercial applications. Of all the potential sources of hydrogen, natural gas offers many advantages. It is widely available, clean, and can be converted to hydrogen relatively easily. When catalytic steam reforming is used to generate hydrogen from natural gas, it is essential that sulfur compounds in the natural gas are removed upstream of the reformer and various types of desulfurisation processes are available. In addition, the quality of fuel required for each type of fuel cell varies according to the anode material used, and the cell temperature. Low temperature cells will not tolerate high concentrations of carbon monoxide, whereas the molten fuel cell (MCFC) and solid oxide fuel cell (SOFC) anodes contain nickel on which it is possible to electrochemically oxidise carbon monoxide directly. The ability to internally reform fuel gas is a feature of the MCFC and SOFC. Internal reforming can give benefits in terms of increased electrical efficiency owing to the reduction in the required cell cooling and therefore parasitic system losses. Direct electrocatalysis of hydrocarbon oxidation has been the elusive goal of fuel cell developers over many years and recent laboratory results are encouraging. This paper reviews the principal methods of converting natural gas into hydrogen, namely catalytic steam reforming, autothermic reforming, pyrolysis and partial oxidation; it reviews currently available purification techniques and discusses some recent advances in internal reforming and the direct use of natural gas in fuel cells.

  16. Gas1 expression in parietal cells of Bowman's capsule in experimental diabetic nephropathy.

    Science.gov (United States)

    Luna-Antonio, Brenda I; Rodriguez-Muñoz, Rafael; Namorado-Tonix, Carmen; Vergara, Paula; Segovia, Jose; Reyes, Jose L

    2017-07-01

    Gas1 (Growth Arrest-Specific 1) is a pleiotropic protein with novel functions including anti-proliferative and proapoptotic activities. In the kidney, the expression of Gas1 has been described in mesangial cells. In this study, we described that renal parietal cells of Bowman's capsule (BC) and the distal nephron cells also express Gas1. The role of Gas1 in the kidney is not yet known. There is a subpopulation of progenitor cells in Bowman's capsule with self-renewal properties which can eventually differentiate into podocytes as a possible mechanism of regeneration in the early stages of diabetic nephropathy. We analyzed the expression of Gas1 in the parietal cells of Bowman's capsule in murine experimental diabetes. We found that diabetes reduced the expression of Gas1 and increased the expression of progenitor markers like NCAM, CD24, and SIX1/2, and mesenchymal markers like PAX2 in the Bowman's capsule. We also analyzed the expression of WT1 (a podocyte-specific marker) on BC and observed an increase in the number of WT1 positive cells in diabetes. In contrast, nephrin, another podocyte-specific protein, decreases its expression in the first week of diabetes in the glomerular tuft, which is gradually restored during the second and third weeks of diabetes. These results suggest that in diabetes the decrease of Gas1 promotes the activation of parietal progenitor cells of Bowman's capsule that might differentiate into podocytes and compensate their loss observed in this pathology.

  17. Method and system for purification of gas streams for solid oxide cells

    DEFF Research Database (Denmark)

    2011-01-01

    of: - providing at least one scrubber in the gas stream at the inlet side of the first electrode of the solid oxide cell; and/or providing at least one scrubber in the gas stream at the inlet side of the second electrode of the solid oxide cell; and - purifying the gas streams towards the first...... and second electrode; wherein the at least one scrubber in the gas stream at the inlet side of the first electrode and/or the at least one scrubber in the gas stream at the inlet side of the second electrode comprises a material suitable as an electrolyte material and a material suitable as an electrode...... material, and wherein the material suitable as an electrolyte material and a material suitable as an electrode material form triple phase boundaries similar to or identical to the triple phase boundaries of the electrode for which the gas stream is purified with the at least one scrubber....

  18. Gas

    International Nuclear Information System (INIS)

    1996-01-01

    The French government has decided to modify the conditions of extension of local natural gas authorities to neighbouring districts. The European Union is studying the conditions of internal gas market with the objective of more open markets although considering public service requirements

  19. Incident at university research facility - pressure testing of gas hydrate cell

    DEFF Research Database (Denmark)

    Jensen, Niels; Jørgensen, Sten Bay

    2014-01-01

    A master student designed a cell for observing the development of gas hydrates as conditions in the cell were changed. The supervisor asked for a pressure test of the cell before the experiments started. The student chose-to perform the pressure test using compressed air and this resulted in one...

  20. Endogenous GAS6 and Mer receptor signaling regulate prostate cancer stem cells in bone marrow.

    Science.gov (United States)

    Jung, Younghun; Decker, Ann M; Wang, Jingcheng; Lee, Eunsohl; Kana, Lulia A; Yumoto, Kenji; Cackowski, Frank C; Rhee, James; Carmeliet, Peter; Buttitta, Laura; Morgan, Todd M; Taichman, Russell S

    2016-05-03

    GAS6 and its receptors (Tryo 3, Axl, Mer or "TAM") are known to play a role in regulating tumor progression in a number of settings. Previously we have demonstrated that GAS6 signaling regulates invasion, proliferation, chemotherapy-induced apoptosis of prostate cancer (PCa) cells. We have also demonstrated that GAS6 secreted from osteoblasts in the bone marrow environment plays a critical role in establishing prostate tumor cell dormancy. Here we investigated the role that endogenous GAS6 and Mer receptor signaling plays in establishing prostate cancer stem cells in the bone marrow microenvironment.We first observed that high levels of endogenous GAS6 are expressed by disseminated tumor cells (DTCs) in the bone marrow, whereas relatively low levels of endogenous GAS6 are expressed in PCa tumors grown in a s.c. Interestingly, elevated levels of endogenous GAS6 were identified in putative cancer stem cells (CSCs, CD133+/CD44+) compared to non-CSCs (CD133-/CD44-) isolated from PCa/osteoblast cocultures in vitro and in DTCs isolated from the bone marrow 24 hours after intracardiac injection. Moreover, we found that endogenous GAS6 expression is associated with Mer receptor expression in growth arrested (G1) PCa cells, which correlates with the increase of the CSC populations. Importantly, we found that overexpression of GAS6 activates phosphorylation of Mer receptor signaling and subsequent induction of the CSC phenotype in vitro and in vivo.Together these data suggest that endogenous GAS6 and Mer receptor signaling contribute to the establishment of PCa CSCs in the bone marrow microenvironment, which may have important implications for targeting metastatic disease.

  1. Thermodynamic Performance Study of Biomass Gasification, Solid Oxide Fuel Cell and Micro Gas Turbine Hybrid Systems

    DEFF Research Database (Denmark)

    Bang-Møller, Christian; Rokni, Masoud

    2010-01-01

    A system level modelling study of three combined heat and power systems based on biomass gasification is presented. Product gas is converted in a micro gas turbine (MGT) in the first system, in a solid oxide fuel cell (SOFC) in the second system and in a combined SOFC–MGT arrangement in the third...

  2. Development of coal gas production technology acceptable for fuel cells; Nenryo denchiyo sekitan gas seizo gijutsu ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, T [Center for Coal Utilization, Japan, Tokyo (Japan); Kimura, N; Omata, K [Electric Power Development Co. Ltd., Tokyo (Japan)

    1996-09-01

    In utilizing coal for high-efficiency direct power generation using fuel cells, it is necessary that coal be fed into the fuel cells after having been made into ash-free gaseous fuel. Research and development works are being carried out with an objective to develop a coal gasification furnace most suitable for fuel cells and establish a system to refine coal up to the one that can be fed into fuel cells. Fiscal 1995 has conducted investigations on coal gasification technologies, air separation technologies, and gas refining technologies as the important element technologies, and a trial design on integrated coal gasification fuel cell (IGFC) systems. This paper reports from among the above items the result of the trial design on an IGFC system using molten carbonate fuel cells. The paper describes system comparison on paths of produced gases and anode waste gas, comparison on refining processes using a wet system and a dry system, and parameter studies on oxygen concentration in gasifying agents. It was made clear that the suitable furnace is an oxygen blown coal gasification furnace, and the power generation efficiency at the system terminal can be higher than 53%. 11 figs., 6 tabs.

  3. Microbial Electrolysis Cells for High Yield Hydrogen Gas Production from Organic Matter

    KAUST Repository

    Logan, Bruce E.; Call, Douglas; Cheng, Shaoan; Hamelers, Hubertus V. M.; Sleutels, Tom H. J. A.; Jeremiasse, Adriaan W.; Rozendal, René A.

    2008-01-01

    production rates. MECs used to make hydrogen gas are similar in design to microbial fuel cells (MFCs) that produce electricity, but there are important differences in architecture and analytical methods used to evaluate performance. We review here

  4. Compact and Robust Refilling and Connectorization of Hollow Core Photonic Crystal Fiber Gas Reference Cells

    Science.gov (United States)

    Poberezhskiy, Ilya Y.; Meras, Patrick; Chang, Daniel H.; Spiers, Gary D.

    2007-01-01

    This slide presentation reviews a method for refilling and connectorization of hollow core photonic crystal fiber gas reference cells. Thees hollow-core photonic crystal fiber allow optical propagation in air or vacuum and are for use as gas reference cell is proposed and demonstrated. It relies on torch-sealing a quartz filling tube connected to a mechanical splice between regular and hollow-core fibers.

  5. Performance of PEM fuel cells stack as affected by number of cell and gas flow-rate

    Science.gov (United States)

    Syampurwadi, A.; Onggo, H.; Indriyati; Yudianti, R.

    2017-03-01

    The proton exchange membrane fuel cell (PEMFC) is a promising technology as an alternative green energy due to its high power density, low operating temperatures, low local emissions, quiet operation and fast start up-shutdown. In order to apply fuel cell as portable power supply, the performance investigation of small number of cells is needed. In this study, PEMFC stacks consisting of 1, 3, 5 and 7-cells with an active area of 25 cm2 per cell have been designed and developed. Their was evaluated in variation of gas flow rate. The membrane electrode assembly (MEA) was prepared by hot-pressing commercial gas diffusion electrodes (Pt loading 0.5 mg/cm2) on pre-treated Nafion 117 membrane. The stacks were constructed using bipolar plates in serpentine pattern and Z-type gas flow configuration. The experimental results were presented as polarization and power output curves which show the effects of varying number of cells and H2/O2 flow-rates on the PEMFC performance. The experimental results showed that not only number of cells and gas flow-rates affected the fuel cells performance, but also the operating temperature as a result of electrochemistry reaction inside the cell.

  6. HOT CELL SYSTEM FOR DETERMINING FISSION GAS RETENTION IN METALLIC FUELS

    Energy Technology Data Exchange (ETDEWEB)

    Sell, D. A.; Baily, C. E.; Malewitz, T. J.; Medvedev, P. G.; Porter, D. L.; Hilton, B. A.

    2016-09-01

    A system has been developed to perform measurements on irradiated, sodium bonded-metallic fuel elements to determine the amount of fission gas retained in the fuel material after release of the gas to the element plenum. During irradiation of metallic fuel elements, most of the fission gas developed is released from the fuel and captured in the gas plenums of the fuel elements. A significant amount of fission gas, however, remains captured in closed porosities which develop in the fuel during irradiation. Additionally, some gas is trapped in open porosity but sealed off from the plenum by frozen bond sodium after the element has cooled in the hot cell. The Retained fission Gas (RFG) system has been designed, tested and implemented to capture and measure the quantity of retained fission gas in characterized cut pieces of sodium bonded metallic fuel. Fuel pieces are loaded into the apparatus along with a prescribed amount of iron powder, which is used to create a relatively low melting, eutectic composition as the iron diffuses into the fuel. The apparatus is sealed, evacuated, and then heated to temperatures in excess of the eutectic melting point. Retained fission gas release is monitored by pressure transducers during the heating phase, thus monitoring for release of fission gas as first the bond sodium melts and then the fuel. A separate hot cell system is used to sample the gas in the apparatus and also characterize the volume of the apparatus thus permitting the calculation of the total fission gas release from the fuel element samples along with analysis of the gas composition.

  7. Thermodynamic simulation of biomass gas steam reforming for a solid oxide fuel cell (SOFC system

    Directory of Open Access Journals (Sweden)

    A. Sordi

    2009-12-01

    Full Text Available This paper presents a methodology to simulate a small-scale fuel cell system for power generation using biomass gas as fuel. The methodology encompasses the thermodynamic and electrochemical aspects of a solid oxide fuel cell (SOFC, as well as solves the problem of chemical equilibrium in complex systems. In this case the complex system is the internal reforming of biomass gas to produce hydrogen. The fuel cell input variables are: operational voltage, cell power output, composition of the biomass gas reforming, thermodynamic efficiency, electrochemical efficiency, practical efficiency, the First and Second law efficiencies for the whole system. The chemical compositions, molar flows and temperatures are presented to each point of the system as well as the exergetic efficiency. For a molar water/carbon ratio of 2, the thermodynamic simulation of the biomass gas reforming indicates the maximum hydrogen production at a temperature of 1070 K, which can vary as a function of the biomass gas composition. The comparison with the efficiency of simple gas turbine cycle and regenerative gas turbine cycle shows the superiority of SOFC for the considered electrical power range.

  8. Data on clinical significance of GAS2 in colorectal cancer cells

    Directory of Open Access Journals (Sweden)

    Chun-Chao Chang

    2016-09-01

    Full Text Available The growth arrest-specific 2 (GAS2 was cloned and found to be upregulated in the feces of recurrent CRC patients. This overexpressed GAS2 induced different patterns of gene expressions in CRC cells. Briefly, one cell proliferation marker, Ki-67 antigen (Ki-67, was upregulated in the cells with overexpressed GAS2, “Correlation between proliferation markers: PCNA, Ki-67, MCM-2 and antiapoptotic protein Bcl-2 in colorectal cancer” [1]. Whereas, the expression of another cell proliferation marker, proliferating cell nuclear antigen (PCNA, changed insignificantly [1]. In addition, the mRNA level of one cyclin involving in both cell cycle G1/S and G2/M transitions was also not affected by GAS2 overexpression, “Cdc20 and Cks direct the spindle checkpoint-independent destruction of cyclin A” [2]. The experimental design and procedures in this article can be helpful for understanding the molecular significance of GAS2 in SW480 and SW620 CRC cells.

  9. In-ground operation of Geothermic Fuel Cells for unconventional oil and gas recovery

    Science.gov (United States)

    Sullivan, Neal; Anyenya, Gladys; Haun, Buddy; Daubenspeck, Mark; Bonadies, Joseph; Kerr, Rick; Fischer, Bernhard; Wright, Adam; Jones, Gerald; Li, Robert; Wall, Mark; Forbes, Alan; Savage, Marshall

    2016-01-01

    This paper presents operating and performance characteristics of a nine-stack solid-oxide fuel cell combined-heat-and-power system. Integrated with a natural-gas fuel processor, air compressor, reactant-gas preheater, and diagnostics and control equipment, the system is designed for use in unconventional oil-and-gas processing. Termed a ;Geothermic Fuel Cell; (GFC), the heat liberated by the fuel cell during electricity generation is harnessed to process oil shale into high-quality crude oil and natural gas. The 1.5-kWe SOFC stacks are packaged within three-stack GFC modules. Three GFC modules are mechanically and electrically coupled to a reactant-gas preheater and installed within the earth. During operation, significant heat is conducted from the Geothermic Fuel Cell to the surrounding geology. The complete system was continuously operated on hydrogen and natural-gas fuels for ∼600 h. A quasi-steady operating point was established to favor heat generation (29.1 kWth) over electricity production (4.4 kWe). Thermodynamic analysis reveals a combined-heat-and-power efficiency of 55% at this condition. Heat flux to the geology averaged 3.2 kW m-1 across the 9-m length of the Geothermic Fuel Cell-preheater assembly. System performance is reviewed; some suggestions for improvement are proposed.

  10. Electrode Kinetics and Gas Conversion in Solid Oxide Cells

    DEFF Research Database (Denmark)

    Njodzefon, Jean-Claude

    The solid oxide fuel cell (SOFC) converts hydrogen, carbon monoxide and hydrocarbon fuels (directly) into electricity with very high efficiencies and has demonstrated almost comparable performance when operated in reverse mode as a solid oxide electrolysis cell (SOEC). In this case electrical (and...... thermal) energy is stored as chemical energy of reaction products. To this end, the cells are fed with steam (H2O electrolysis), carbon dioxide (CO2 electrolysis) or a mixture of both (H2O/CO2 co-electrolysis) and of course electrical (ΔG) and thermal (TΔS) energies for the splitting of reactant compounds...... of the solid oxide cell (SOC) and independent of polarization mode (fuel cell mode or electrolysis mode), the current flowing through the cell is limited by processes such as adsorption and desorption of reactants or products, diffusion through the porous electrodes, activation or charge transfer...

  11. Radioactive rare gas separation using a separation cell with two kinds of membrane differing in gas permeability tendency

    International Nuclear Information System (INIS)

    Ohno, Masayoshi; Ozaki, Osamu; Sato, Hajime; Kimura, Shoji; Miyauchi, Terukatsu.

    1977-01-01

    A separation cell embodying two kinds of membrane-porous and nonporous, i.e. differing in gas permeability - has a separation factor higher than possible with a conventional separation cell with a single kind of membrane. The performance of such separation cells and of cascades constituted thereof are analyzed theoretically and measured experimentally for different conditions of operation, to determine the applicability of the concept to the separation of rare gases from gaseous waste out of nuclear plants. Theoretical considerations indicate that, in a cascade composed of symmetric separation cells, the separation performance can be improved by recycling part of the effluent from a cell back through the same cell (recycling cascade). It is shown that its performance is better than with the arrangement of diverting another effluent several stages upstream. With the recycling cascade, the symmetric separation recycling rate is determined by the depletion separation and enrichment separation factors relevant to the respective membranes. The separation performance of a 9-stage recycling cascade composed of separation cells with silicone rubber tubular membranes and cellulose acetate tubular membranes is derived for a case of Kr separation from N 2 -Kr mixture. The experimental data coincide well with the analytical results. From both the experimental and the analytical results, it is found that the attainable separation coefficient per stage of the cascade comes to average approximately 0.97. (auth.)

  12. Operation of real landfill gas fueled solid oxide fuel cell (SOFC) using internal dry reforming

    DEFF Research Database (Denmark)

    Langnickel, Hendrik; Hagen, Anke

    2017-01-01

    Biomass is one renewable energy source, which is independent from solar radiation and wind effect. Solid oxide fuel cells (SOFC’s) are able to convert landfill gas derived from landfill directly into electricity and heat with a high efficiency. In the present work a planar 16cm2 SOFC cell...... was necessary to prevent poisoning and thereby to decrease the degradation rate....

  13. Analysis of Gas Leakage and Current Loss of Solid Oxide Fuel Cells by Screen Printing

    DEFF Research Database (Denmark)

    Jia, Chuan; Han, Minfang; Chen, Ming

    2017-01-01

    Two types of anode supported solid oxide fuel cell (SOFC) NiO-YSZ/YSZ/GDC/LSCF with the same structure and different manufacturing process were tested. Gas leakage was suspected for cells manufactured with screen printing technique. Effective leak current densities for both types of cells were...... calculated. Their performances of electrochemical impedance spectroscopy (EIS) were compared and distribution function of relaxation times (DRT) technique was also used to find the clue of gas leakage. Finally, thinning and penetrating holes were observed in electrolyte layer, which confirmed the occurrence...

  14. High temperature and high pressure gas cell for quantitative spectroscopic measurements

    International Nuclear Information System (INIS)

    Christiansen, Caspar; Stolberg-Rohr, Thomine; Fateev, Alexander; Clausen, Sønnik

    2016-01-01

    A high temperature and high pressure gas cell (HTPGC) has been manufactured for quantitative spectroscopic measurements in the pressure range 1–200 bar and temperature range 300–1300 K. In the present work the cell was employed at up to 100 bar and 1000 K, and measured absorption coefficients of a CO_2–N_2 mixture at 100 bar and 1000 K are revealed for the first time, exceeding the high temperature and pressure combinations previously reported. This paper discusses the design considerations involved in the construction of the cell and presents validation measurements compared against simulated spectra, as well as published experimental data. - Highlights: • A ceramic gas cell designed for gas measurements up to 1300 K and 200 bar. • The first recorded absorption spectrum of CO_2 at 1000 K and 101 bar is presented. • Voigt profiles might suffice in the modeling of radiation from CO_2 in combustion.

  15. Gas6 induces cancer cell migration and epithelial–mesenchymal transition through upregulation of MAPK and Slug

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yunhee [Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Immunotherapy Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon (Korea, Republic of); Lee, Mira [Immunotherapy Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon (Korea, Republic of); Kim, Semi, E-mail: semikim@kribb.re.kr [Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Immunotherapy Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon (Korea, Republic of)

    2013-04-26

    Highlights: •We investigated the molecular mechanisms underlying Gas6-mediated cancer cell migration. •Gas6 treatment and subsequent Axl activation induce cell migration and EMT via upregulation of Slug. •Slug expression mediated by Gas6 is mainly through c-Jun and ATF-2 in an ERK1/2 and JNK-dependent manner. •The Gas6/Axl-Slug axis may be exploited as a target for anti-cancer metastasis therapy. -- Abstract: Binding of Gas6 to Axl (Gas6/Axl axis) alters cellular functions, including migration, invasion, proliferation, and survival. However, the molecular mechanisms underlying Gas6-mediated cell migration remain poorly understood. In this study, we found that Gas6 induced the activation of JNK and ERK1/2 signaling in cancer cells expressing Axl, resulting in the phosphorylation of activator protein-1 (AP-1) transcription factors c-Jun and ATF-2, and induction of Slug. Depletion of c-Jun or ATF-2 by siRNA attenuated the Gas6-induced expression of Slug. Slug expression was required for cell migration and E-cadherin reduction/vimentin induction induced by Gas6. These results suggest that Gas6 induced cell migration via Slug upregulation in JNK- and ERK1/2-dependent mechanisms. These data provide an important insight into the molecular mechanisms mediating Gas6-induced cell migration.

  16. Leukemic Cells "Gas Up" Leaky Bone Marrow Blood Vessels.

    Science.gov (United States)

    Itkin, Tomer; Rafii, Shahin

    2017-09-11

    In this issue of Cancer Cell, Passaro et al. demonstrate how leukemia through aberrant induction of reactive oxygen species and nitric oxide production trigger marrow vessel leakiness, instigating pro-leukemic function. Disrupted tumor blood vessels promote exhaustion of non-malignant stem and progenitor cells and may facilitate leukemia relapse following chemotherapeutic treatment. Copyright © 2017. Published by Elsevier Inc.

  17. Experimental Study and Comparison of Various Designs of Gas Flow Fields to PEM Fuel Cells and Cell Stack Performance

    International Nuclear Information System (INIS)

    Liu, Hong; Li, Peiwen; Juarez-Robles, Daniel; Wang, Kai; Hernandez-Guerrero, Abel

    2014-01-01

    In this study, a significant number of experimental tests to proton exchange membrane (PEM) fuel cells were conducted to investigate the effect of gas flow fields on fuel cell performance. Graphite plates with various flow field or flow channel designs, from literature survey and also novel designs by the authors, were used for the PEM fuel cell assembly. The fabricated fuel cells have an effective membrane area of 23.5 cm 2 . The results showed that the serpentine flow channel design is still favorable, giving the best single fuel cell performance amongst all the studied flow channel designs. A novel symmetric serpentine flow field was proposed for a relatively large sized fuel cell application. Four fuel cell stacks each including four cells were assembled using different designs of serpentine flow channels. The output power performances of fuel cell stacks were compared and the novel symmetric serpentine flow field design is recommended for its very good performance.

  18. Dynamics of gas cell coalescence during baking expansion of leavened dough.

    Science.gov (United States)

    Miś, Antoni; Nawrocka, Agnieszka; Lamorski, Krzysztof; Dziki, Dariusz

    2018-01-01

    The investigation of the dynamics of gas cell coalescence, i.e. a phenomenon that deteriorates the homogeneity of the cellular structure of bread crumb, was carried out performing simultaneously measurements of the dough volume, pressure, and viscosity. It was demonstrated that, during the baking expansion of chemically leavened wheat flour dough, the maximum growth rate of the gas cell radius determined from the ratio of pressure exerted by the expanded dough to its viscosity was on average four-fold lower than that calculated from volume changes in the gas phase of the dough. Such a high discrepancy was interpreted as a result of the course of coalescence, and a formula for determination of its rate was developed. The coalescence rate in the initial baking expansion phase had negative values, indicating nucleation of newly formed gas cells, which increased the number of gas cells even by 8%. In the next baking expansion phase, the coalescence rate started to exhibit positive values, reflecting dominance of the coalescence phenomenon over nucleation. The maximum coalescence rates indicate that, during the period of the most intensive dough expansion, the number of gas cells decreased by 2-3% within one second. At the end of the formation of bread crumb, the number of the gas cells declined by 55-67% in comparison with the initial value. The correctness of the results was positively verified using X-ray micro-computed tomography. The developed method can be a useful tool for more profound exploration of the coalescence phenomenon at various stages of evolution of the cellular structure and its determinants, which may contribute to future development of more effective methods for improving the texture and sensory quality of bread crumb. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Hydrogen gas alleviates oxygen toxicity by reducing hydroxyl radical levels in PC12 cells.

    Directory of Open Access Journals (Sweden)

    Junchao Yu

    Full Text Available Hyperbaric oxygen (HBO therapy through breathing oxygen at the pressure of above 1 atmosphere absolute (ATA is useful for varieties of clinical conditions, especially hypoxic-ischemic diseases. Because of generation of reactive oxygen species (ROS, breathing oxygen gas at high pressures can cause oxygen toxicity in the central nervous system, leading to multiple neurological dysfunction, which limits the use of HBO therapy. Studies have shown that Hydrogen gas (H2 can diminish oxidative stress and effectively reduce active ROS associated with diseases. However, the effect of H2 on ROS generated from HBO therapy remains unclear. In this study, we investigated the effect of H2 on ROS during HBO therapy using PC12 cells. PC12 cells cultured in medium were exposed to oxygen gas or mixed oxygen gas and H2 at 1 ATA or 5 ATA. Cells viability and oxidation products and ROS were determined. The data showed that H2 promoted the cell viability and inhibited the damage in the cell and mitochondria membrane, reduced the levels of lipid peroxidation and DNA oxidation, and selectively decreased the levels of •OH but not disturbing the levels of O2•-, H2O2, or NO• in PC12 cells during HBO therapy. These results indicated that H2 effectively reduced •OH, protected cells against oxygen toxicity resulting from HBO therapy, and had no effect on other ROS. Our data supported that H2 could be potentially used as an antioxidant during HBO therapy.

  20. Effect of Slotted Anode on Gas Bubble Behaviors in Aluminum Reduction Cell

    Science.gov (United States)

    Sun, Meijia; Li, Baokuan; Li, Linmin; Wang, Qiang; Peng, Jianping; Wang, Yaowu; Cheung, Sherman C. P.

    2017-12-01

    In the aluminum reduction cells, gas bubbles are generated at the bottom of the anode which eventually reduces the effective current contact area and the system efficiency. To encourage the removal of gas bubbles, slotted anode has been proposed and increasingly adopted by some industrial aluminum reduction cells. Nonetheless, the exact gas bubble removal mechanisms are yet to be fully understood. A three-dimensional (3D) transient, multiphase flow mathematical model coupled with magnetohydrodynamics has been developed to investigate the effect of slotted anode on the gas bubble movement. The Eulerian volume of fluid approach is applied to track the electrolyte (bath)-molten aluminum (metal) interface. Meanwhile, the Lagrangian discrete particle model is employed to handle the dynamics of gas bubbles with considerations of the buoyancy force, drag force, virtual mass force, and pressure gradient force. The gas bubble coalescence process is also taken into account based on the O'Rourke's algorithm. The two-way coupling between discrete bubbles and fluids is achieved by the inter-phase momentum exchange. Numerical predictions are validated against the anode current variation in an industrial test. Comparing the results using slotted anode with the traditional one, the time-averaged gas bubble removal rate increases from 36 to 63 pct; confirming that the slotted anode provides more escaping ways and shortens the trajectories for gas bubbles. Furthermore, the slotted anode also reduces gas bubble's residence time and the probability of coalescence. Moreover, the bubble layer thickness in aluminum cell with slotted anode is reduced about 3.5 mm (17.4 pct), so the resistance can be cut down for the sake of energy saving and the metal surface fluctuation amplitude is significantly reduced for the stable operation due to the slighter perturbation with smaller bubbles.

  1. Malignant human cell transformation of Marcellus Shale gas drilling flow back water

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Yixin [Department of Epidemiology, Shanghai Jiaotong University School of Public Health (China); Department of Environmental Medicine, New York University School of Medicine, Tuxedo, NY 10987 (United States); Chen, Tingting [School of Material Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Shen, Steven S. [Biochemistry and Molecular Pharmaceutical, New York University School of Medicine (United States); Niu, Yingmei; DesMarais, Thomas L.; Linn, Reka; Saunders, Eric; Fan, Zhihua [Department of Environmental Medicine, New York University School of Medicine, Tuxedo, NY 10987 (United States); Lioy, Paul [Robert Wood Johnson Medical School Rutgers, The State University of New Jersey, Piscataway, NJ 08854 (United States); Kluz, Thomas; Chen, Lung-Chi [Department of Environmental Medicine, New York University School of Medicine, Tuxedo, NY 10987 (United States); Wu, Zhuangchun, E-mail: wuzhuangchun@mail.njust.edu.cn [College of Science, Donghua University, Shanghai 201620 (China); Costa, Max, E-mail: max.costa@nyumc.org [Department of Environmental Medicine, New York University School of Medicine, Tuxedo, NY 10987 (United States)

    2015-10-01

    The rapid development of high-volume horizontal hydraulic fracturing for mining natural gas from shale has posed potential impacts on human health and biodiversity. The produced flow back waters after hydraulic stimulation are known to carry high levels of saline and total dissolved solids. To understand the toxicity and potential carcinogenic effects of these wastewaters, flow back waters from five Marcellus hydraulic fracturing oil and gas wells were analyzed. The physicochemical nature of these samples was analyzed by inductively coupled plasma mass spectrometry and scanning electron microscopy/energy dispersive X-ray spectroscopy. A cytotoxicity study using colony formation as the endpoint was carried out to define the LC{sub 50} values of test samples using human bronchial epithelial cells (BEAS-2B). The BEAS-2B cell transformation assay was employed to assess the carcinogenic potential of the samples. Barium and strontium were among the most abundant metals in these samples and the same metals were found to be elevated in BEAS-2B cells after long-term treatment. BEAS-2B cells treated for 6 weeks with flow back waters produced colony formation in soft agar that was concentration dependent. In addition, flow back water-transformed BEAS-2B cells show better migration capability when compared to control cells. This study provides information needed to assess the potential health impact of post-hydraulic fracturing flow back waters from Marcellus Shale natural gas mining. - Highlights: • This is the first report of potential cytotoxicity and transforming activity of Marcellus shale gas mining flow back to mammalian cells. • Barium and Strontium were elevated in flow back water exposed cells. • Flow back water malignantly transformed cells and formed tumor in athymic nude mice. • Flow back transformed cells exhibited altered transcriptome with dysregulated cell migration pathway and adherent junction pathway.

  2. Malignant human cell transformation of Marcellus Shale gas drilling flow back water

    International Nuclear Information System (INIS)

    Yao, Yixin; Chen, Tingting; Shen, Steven S.; Niu, Yingmei; DesMarais, Thomas L.; Linn, Reka; Saunders, Eric; Fan, Zhihua; Lioy, Paul; Kluz, Thomas; Chen, Lung-Chi; Wu, Zhuangchun; Costa, Max

    2015-01-01

    The rapid development of high-volume horizontal hydraulic fracturing for mining natural gas from shale has posed potential impacts on human health and biodiversity. The produced flow back waters after hydraulic stimulation are known to carry high levels of saline and total dissolved solids. To understand the toxicity and potential carcinogenic effects of these wastewaters, flow back waters from five Marcellus hydraulic fracturing oil and gas wells were analyzed. The physicochemical nature of these samples was analyzed by inductively coupled plasma mass spectrometry and scanning electron microscopy/energy dispersive X-ray spectroscopy. A cytotoxicity study using colony formation as the endpoint was carried out to define the LC 50 values of test samples using human bronchial epithelial cells (BEAS-2B). The BEAS-2B cell transformation assay was employed to assess the carcinogenic potential of the samples. Barium and strontium were among the most abundant metals in these samples and the same metals were found to be elevated in BEAS-2B cells after long-term treatment. BEAS-2B cells treated for 6 weeks with flow back waters produced colony formation in soft agar that was concentration dependent. In addition, flow back water-transformed BEAS-2B cells show better migration capability when compared to control cells. This study provides information needed to assess the potential health impact of post-hydraulic fracturing flow back waters from Marcellus Shale natural gas mining. - Highlights: • This is the first report of potential cytotoxicity and transforming activity of Marcellus shale gas mining flow back to mammalian cells. • Barium and Strontium were elevated in flow back water exposed cells. • Flow back water malignantly transformed cells and formed tumor in athymic nude mice. • Flow back transformed cells exhibited altered transcriptome with dysregulated cell migration pathway and adherent junction pathway.

  3. A Gas Cell Based on Hollow-Core Photonic Crystal Fiber (PCF and Its Application for the Detection of Greenhouse Gas (GHG: Nitrous Oxide (N2O

    Directory of Open Access Journals (Sweden)

    Jonas K. Valiunas

    2016-01-01

    Full Text Available The authors report the detection of nitrous oxide gas using intracavity fiber laser absorption spectroscopy. A gas cell based on a hollow-core photonic crystal fiber was constructed and used inside a fiber ring laser cavity as an intracavity gas cell. The fiber laser in the 1.55 μm band was developed using a polarization-maintaining erbium-doped fiber as the gain medium. The wavelength of the laser was selected by a fiber Bragg grating (FBG, and it matches one of the absorption lines of the gas under investigation. The laser wavelength contained multilongitudinal modes, which increases the sensitivity of the detection system. N2O gas has overtones of the fundamental absorption bands and rovibrational transitions in the 1.55 μm band. The system was operated at room temperature and was capable of detecting nitrous oxide gas at sub-ppmv concentration level.

  4. Resonance ionization in a gas cell: a feasibility study for a laser ion source

    International Nuclear Information System (INIS)

    Qamhieh, Z.N.; Vandeweert, E.; Silverans, R.E.; Duppen, P. van; Huyse, M.; Vermeeren, L.

    1992-01-01

    A laser ion source based on resonance photo-ionization in a gas cell is proposed. The gas cell, filled with helium, consists of a target chamber in which the recoil products are stopped and neutralized, and an ionization chamber where the atoms of interest are selectively ionized by the laser light. The extraction of the ions from the ionization chamber through the exit hole-skimmer setup is similar to the ion-guide system. The conditions to obtain an optimal system are given. The results of a two-step one-laser resonance photo-ionization of nickel and the first results of laser ionization in a helium buffer gas cell are presented. (orig.)

  5. A NEW GAS CELL FOR HIGH-PRECISION DOPPLER MEASUREMENTS IN THE NEAR-INFRARED

    International Nuclear Information System (INIS)

    Valdivielso, L.; Esparza, P.; MartIn, E. L.; Maukonen, D.; Peale, R. E.

    2010-01-01

    High-resolution spectroscopy in the near-infrared could become the leading method for discovering extra-solar planets around very low mass stars and brown dwarfs. In order to help to achieve an accuracy of ∼m s -1 , we are developing a gas cell which consists of a mixture of gases whose absorption spectral lines span all over the near-infrared region. We present the most promising mixture, made of acetylene, nitrous oxide, ammonia, chloromethanes, and hydrocarbons. The mixture is contained in a small size 13 cm long gas cell and covers most of the H and K bands. It also shows small absorptions in the J band, but they are few and not sharp enough for near-infrared wavelength calibration. We describe the working method and experiments, and compare our results with the state of the art for near-infrared gas cells.

  6. Advanced gas-emission anode design for microfluidic fuel cell eliminating bubble accumulation

    International Nuclear Information System (INIS)

    Zhang, Hao; Xuan, Jin; Wang, Huizhi; Leung, Dennis Y C; Xu, Hong; Zhang, Li

    2017-01-01

    A microfluidic fuel cell is a low cost, easily fabricated energy device and is considered a promising energy supplier for portable electronics. However, the currently developed microfluidic fuel cells that are fed with hydrocarbon fuels are confronted with a bubble problem especially when operating at high current density conditions. In this work, a gas-emission anode is presented to eliminate the gas accumulation at the anode. This gas-emission anode is verified as a valid design for discharging gaseous products, which is especially beneficial for stable operation of microfluidic fuel cells. The electrochemical performance of a counter-flow microfluidic fuel cell equipped with a gas-emission anode was measured. The results indicate that the specific design of the gas-emission anode is essential for reducing the oxygen reduction reaction parasitic effect at the anode. Fuel utilization of 76.4% was achieved at a flow rate of 0.35 µ l min −1 . Current–voltage curves of single electrodes were measured and the parasitic effect at the anode was identified as the main performance limiting factor in the presented anode design. (paper)

  7. Special considerations on operating a fuel cell power plant using natural gas with marginal heating value

    Energy Technology Data Exchange (ETDEWEB)

    Moses, L. Ng; Chien-Liang Lin [Industrial Technology Research Institute, Taiwan (China); Ya-Tang Cheng [Power Research Institute, Taiwan (China)

    1996-12-31

    In realizing new power generation technologies in Taiwan, a phosphoric acid fuel cell power plant (model PC2513, ONSI Corporation) has been installed in the premises of the Power Research Institute of the Taiwan Power Company in Taipei County of Taiwan. The pipeline gas supplying to the site of this power plant has a high percentage of carbon dioxide and thus a slightly lower heating value than that specified by the manufacturer. Because of the lowering of heating value of input gas, the highest Output power from the power plant is understandably less than the rated power of 200 kW designed. Further, the transient response of the power plant as interrupted from the Grid is also affected. Since this gas is also the pipeline gas supplying to the heavily populated Taipei Municipal area, it is conceivable that the success of the operations of fuel cells using this fuel is of vital importance to the promotion of the use of this power generation technology in Taiwan. Hence, experiments were set up to assess the feasibility of this fuel cell power plant using the existing pipeline gas in this part of Taiwan where fuel cells would most likely find useful.

  8. Integration of A Solid Oxide Fuel Cell into A 10 MW Gas Turbine Power Plant

    Directory of Open Access Journals (Sweden)

    Denver F. Cheddie

    2010-04-01

    Full Text Available Power generation using gas turbine power plants operating on the Brayton cycle suffers from low efficiencies. In this work, a solid oxide fuel cell (SOFC is proposed for integration into a 10 MW gas turbine power plant, operating at 30% efficiency. The SOFC system utilizes four heat exchangers for heat recovery from both the turbine outlet and the fuel cell outlet to ensure a sufficiently high SOFC temperature. The power output of the hybrid plant is 37 MW at 66.2% efficiency. A thermo-economic model predicts a payback period of less than four years, based on future projected SOFC cost estimates.

  9. Tuneable diode laser gas analyser for methane measurements on a large scale solid oxide fuel cell

    Science.gov (United States)

    Lengden, Michael; Cunningham, Robert; Johnstone, Walter

    2011-10-01

    A new in-line, real time gas analyser is described that uses tuneable diode laser spectroscopy (TDLS) for the measurement of methane in solid oxide fuel cells. The sensor has been tested on an operating solid oxide fuel cell (SOFC) in order to prove the fast response and accuracy of the technology as compared to a gas chromatograph. The advantages of using a TDLS system for process control in a large-scale, distributed power SOFC unit are described. In future work, the addition of new laser sources and wavelength modulation will allow the simultaneous measurement of methane, water vapour, carbon-dioxide and carbon-monoxide concentrations.

  10. Thermodynamic analysis of solid oxide fuel cell gas turbine systems operating with various biofuels

    Energy Technology Data Exchange (ETDEWEB)

    Patel, H.C.; Woudstra, T.; Aravind, P.V. [Process and Energy Laboratory, Delft University of Technology, Section Energy Technology, Leeghwaterstraat 44, 2628 CA Delft (Netherlands)

    2012-12-15

    Solid oxide fuel cell-gas turbine (SOFC-GT) systems provide a thermodynamically high efficiency alternative for power generation from biofuels. In this study biofuels namely methane, ethanol, methanol, hydrogen, and ammonia are evaluated exergetically with respect to their performance at system level and in system components like heat exchangers, fuel cell, gas turbine, combustor, compressor, and the stack. Further, the fuel cell losses are investigated in detail with respect to their dependence on operating parameters such as fuel utilization, Nernst voltage, etc. as well as fuel specific parameters like heat effects. It is found that the heat effects play a major role in setting up the flows in the system and hence, power levels attained in individual components. The per pass fuel utilization dictates the efficiency of the fuel cell itself, but the system efficiency is not entirely dependent on fuel cell efficiency alone, but depends on the split between the fuel cell and gas turbine powers which in turn depends highly on the nature of the fuel and its chemistry. Counter intuitively it is found that with recycle, the fuel cell efficiency of methane is less than that of hydrogen but the system efficiency of methane is higher. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Gas-filled cell as a narrow bandwidth bandpass filter in the VUV wavelength range

    Energy Technology Data Exchange (ETDEWEB)

    Geloni, Gianluca [European XFEL GmbH, Hamburg (Germany); Kocharyan, Vitali; Saldin, Evgeni [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2011-04-15

    We propose a method for spectrally filtering radiation in the VUV wavelength range by means of a monochromator constituted by a cell filled with a resonantly absorbing rare gas. Around particular wavelengths, the gas exhibits narrow-bandwidth absorbing resonances following the Fano profile. In particular, within the photon energy range 60 eV-65 eV, the correlation index of the Fano profiles for the photoionization spectra in Helium is equal to unity, meaning that the minimum of the cross-section is exactly zero. For sufficiently large column density in the gas cell, the spectrum of the incoming radiation will be attenuated by the background cross-section of many orders of magnitude, except for those wavelengths close to the point where the cross-section is zero. Remarkable advantages of a gas monochromator based on this principle are simplicity, efficiency and narrow-bandwidth. A gas monochromator installed in the experimental hall of a VUV SASE FEL facility would enable the delivery of a single-mode VUV laser beam. The design is identical to that of already existing gas attenuator systems for VUV or X-ray FELs. We present feasibility study and exemplifications for the FLASH facility in the VUV regime. (orig.)

  12. Outer segment phagocytosis by cultured retinal pigment epithelial cells requires Gas6.

    Science.gov (United States)

    Hall, M O; Prieto, A L; Obin, M S; Abrams, T A; Burgess, B L; Heeb, M J; Agnew, B J

    2001-10-01

    The function and viability of vertebrate photoreceptors requires the daily phagocytosis of photoreceptor outer segments (OS) by the adjacent retinal pigment epithelium (RPE). We demonstrate here a critical role in this process for Gas6 and by implication one of its receptor protein tyrosine kinases (RTKs), Mertk (Mer). Gas6 specifically and selectively stimulates the phagocytosis of OS by normal cultured rat RPE cells. The magnitude of the response is dose-dependent and shows an absolute requirement for calcium. By contrast the Royal College of Surgeons (RCS) rat RPE cells, in which a mutation in the gene Mertk results in the expression of a truncated, non-functional receptor, does not respond to Gas6. These data strongly suggest that activation of Mertk by its ligand, Gas6, is the specific signaling pathway responsible for initiating the ingestion of shed OS. Moreover, photoreceptor degeneration in the RCS rat retina, which lacks Mertk, and in humans with a mutation in Mertk, strongly suggests that the Gas6/Mertk signaling pathway is essential for photoreceptor viability. We believe that this is the first demonstration of a specific function for Gas6 in the eye. Copyright 2001 Academic Press.

  13. Experimental procedures for the calibration of scintillation cells used in the determination of radon gas concentrations

    International Nuclear Information System (INIS)

    Grenier, M; Bigu, J.

    1982-02-01

    Experimental and analytical procedures are described for the calibration of scintillation cells used for the determination of radon gas concentration. In-house designed and built scintillation cells, used routinely in the monitoring of radon gas in uranium mine underground environments and in the laboratory, were calibrated. The cells had a volume of approximately 158 cm 3 and an α-counting efficiency ranging from 50% to 64%. Calibration factors for the cells were determined. Values ranged approximately from 0.177 cpm/pCiL -1 (4.77 cpm/BqL -1 ) to 0.224 cpm/pCiL -1 (6.05 cpm/BqL -1 ). The calibration facilities at the Elliot Lake Laboratory are briefly described

  14. CAPTURING EXHAUST CO2 GAS USING MOLTEN CARBONATE FUEL CELLS

    Directory of Open Access Journals (Sweden)

    Prateek Dhawan

    2016-03-01

    Full Text Available Carbon dioxide is considered as one of the major contenders when the question of greenhouse effect arises. So for any industry or power plant it is of utmost importance to follow certain increasingly stringent environment protection rules and laws. So it is significant to keep eye on any possible methods to reduce carbon dioxide emissions in an efficient way. This paper reviews the available literature so as to try to provide an insight of the possibility of using Molten Carbonate Fuel Cells (MCFCs as the carbon capturing and segregating devices and the various factors that affect the performance of MCFCs during the process of CO2 capture.

  15. Microbial Electrolysis Cells for High Yield Hydrogen Gas Production from Organic Matter

    KAUST Repository

    Logan, Bruce E.

    2008-12-01

    The use of electrochemically active bacteria to break down organic matter, combined with the addition of a small voltage (>0.2 V in practice) in specially designed microbial electrolysis cells (MECs), can result in a high yield of hydrogen gas. While microbial electrolysis was invented only a few years ago, rapid developments have led to hydrogen yields approaching 100%, energy yields based on electrical energy input many times greater than that possible by water electrolysis, and increased gas production rates. MECs used to make hydrogen gas are similar in design to microbial fuel cells (MFCs) that produce electricity, but there are important differences in architecture and analytical methods used to evaluate performance. We review here the materials, architectures, performance, and energy efficiencies of these MEC systems that show promise as a method for renewable and sustainable energy production, and wastewater treatment. © 2008 American Chemical Society.

  16. Fuel cells: new technology of natural gas for energetical building; Pilas de combustible: nueva tecnologia de gas natural para edificios energeticamente autoabastecidos

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez, A. M.

    2000-07-01

    Fuel Cells have emerged in the last decade as one of the most promising new and sustainable natural gas technologies for meeting the energy needs of all the economy sectors into the 21st century. Fuel Cells are an environmentally clean, quiet, and highly efficient method for generating electricity and heat from natural gas. A fuel cell is an electrochemical device that converts the chemical energy of a fuel directly to usable energy (electricity and heat) without combustion. For this reason, the application and use of the fuel cell technology may be the most important technological advancement of the next century. At the beginning of the 2000 year Sociedad de Gas de Euskadi, s. a. started a demonstration project in favour of the high-temperature planar solid oxide fuel cell (SOFC) for domestic micro-CHP utilization. This type is certainly most exacting from the materials standpoint, and it offers the advantage of uncomplicated fuel pretreatment. (Author)

  17. Microbial Electrolysis Cells for High Yield Hydrogen Gas Production from Organic Matter

    NARCIS (Netherlands)

    Logan, B.E.; Call, D.; Cheng, S.; Hamelers, H.V.M.; Sleutels, T.H.J.A.; Jeremiasse, A.W.; Rozendal, R.A.

    2008-01-01

    The use of electrochemically active bacteria to break down organic matter, combined with the addition of a small voltage (>0.2 V in practice) in specially designed microbial electrolysis cells (MECs), can result in a high yield of hydrogen gas. While microbial electrolysis was invented only a few

  18. Accelerated Degradation for Hardware in the Loop Simulation of Fuel Cell-Gas Turbine Hybrid System

    DEFF Research Database (Denmark)

    Abreu-Sepulveda, Maria A.; Harun, Nor Farida; Hackett, Gregory

    2015-01-01

    The U.S. Department of Energy (DOE)-National Energy Technology Laboratory (NETL) in Morgantown, WV has developed the hybrid performance (HyPer) project in which a solid oxide fuel cell (SOFC) one-dimensional (1D), real-time operating model is coupled to a gas turbine hardware system by utilizing...

  19. Aging studies on micro-fabricated alkali buffer-gas cells for miniature atomic clocks

    International Nuclear Information System (INIS)

    Abdullah, S.; Affolderbach, C.; Gruet, F.; Mileti, G.

    2015-01-01

    We report an aging study on micro-fabricated alkali vapor cells using neon as a buffer gas. An experimental atomic clock setup is used to measure the cell's intrinsic frequency, by recording the clock frequency shift at different light intensities and extrapolating to zero intensity. We find a drift of the cell's intrinsic frequency of (−5.2 ± 0.6) × 10 −11 /day and quantify deterministic variations in sources of clock frequency shifts due to the major physical effects to identify the most probable cause of the drift. The measured drift is one order of magnitude stronger than the total frequency variations expected from clock parameter variations and corresponds to a slow reduction of buffer gas pressure inside the cell, which is compatible with the hypothesis of loss of Ne gas from the cell due to its permeation through the cell windows. A negative drift on the intrinsic cell frequency is reproducible for another cell of the same type. Based on the Ne permeation model and the measured cell frequency drift, we determine the permeation constant of Ne through borosilicate glass as (5.7 ± 0.7) × 10 −22 m 2 s −1  Pa −1 at 81 °C. We propose this method based on frequency metrology in an alkali vapor cell atomic clock setup based on coherent population trapping for measuring permeation constants of inert gases

  20. Quantitative assessment of gas cell development during the proofing of dough by magnetic resonance imaging and image analysis

    NARCIS (Netherlands)

    Duynhoven, van J.P.M.; Kempen, van G.M.P.; Sluis, van R.; Rieger, B.; Weegels, P.; Vliet, van L.J.; Nicolaij, K.

    2003-01-01

    The structure of bread crumb is an important factor in consumer acceptance of bakery products. The noninvasive monitoring of the gas cell formation during the proofing of dough can aid in understanding the mechanisms governing the crumb appearance in the baked product. The development of gas cells

  1. Gas composition modeling in a reformed Methanol Fuel Cell system using adaptive Neuro-Fuzzy Inference Systems

    DEFF Research Database (Denmark)

    Justesen, Kristian Kjær; Andreasen, Søren Juhl; Shaker, Hamid Reza

    2013-01-01

    This work presents a method for modeling the gas composition in a Reformed Methanol Fuel Cell system. The method is based on Adaptive Neuro-Fuzzy-Inference-Systems which are trained on experimental data. The developed models are of the H2, CO2, CO and CH3OH mass flows of the reformed gas. The ANFIS......, or fuel cell diagnostics systems....

  2. Ionized gas (plasma) delivery of reactive oxygen species (ROS) into artificial cells

    International Nuclear Information System (INIS)

    Hong, Sung-Ha; Jenkins, A Toby A; Szili, Endre J; Short, Robert D

    2014-01-01

    This study was designed to enhance our understanding of how reactive oxygen species (ROS), generated ex situ by ionized gas (plasma), can affect the regulation of signalling processes within cells. A model system, comprising of a suspension of phospholipid vesicles (cell mimics) encapsulating a ROS reporter, was developed to study the plasma delivery of ROS into cells. For the first time it was shown that plasma unequivocally delivers ROS into cells over a sustained period and without compromising cell membrane integrity. An important consideration in cell and biological assays is the presence of serum, which significantly reduced the transfer efficiency of ROS into the vesicles. These results are key to understanding how plasma treatments can be tailored for specific medical or biotechnology applications. Further, the phospholipid vesicle ROS reporter system may find use in other studies involving the application of free radicals in biology and medicine. (fast track communication)

  3. Ionized gas (plasma) delivery of reactive oxygen species (ROS) into artificial cells

    Science.gov (United States)

    Hong, Sung-Ha; Szili, Endre J.; Jenkins, A. Toby A.; Short, Robert D.

    2014-09-01

    This study was designed to enhance our understanding of how reactive oxygen species (ROS), generated ex situ by ionized gas (plasma), can affect the regulation of signalling processes within cells. A model system, comprising of a suspension of phospholipid vesicles (cell mimics) encapsulating a ROS reporter, was developed to study the plasma delivery of ROS into cells. For the first time it was shown that plasma unequivocally delivers ROS into cells over a sustained period and without compromising cell membrane integrity. An important consideration in cell and biological assays is the presence of serum, which significantly reduced the transfer efficiency of ROS into the vesicles. These results are key to understanding how plasma treatments can be tailored for specific medical or biotechnology applications. Further, the phospholipid vesicle ROS reporter system may find use in other studies involving the application of free radicals in biology and medicine.

  4. Diffusion and Gas Conversion Analysis of Solid Oxide Fuel Cells at Loads via AC Impedance

    Directory of Open Access Journals (Sweden)

    Robert U. Payne

    2011-01-01

    Full Text Available Impedance measurements were conducted under practical load conditions in solid oxide fuel cells of differing sizes. For a 2 cm2 button cell, impedance spectra data were separately measured for the anode, cathode, and total cell. Improved equivalent circuit models are proposed and applied to simulate each of measured impedance data. Circuit elements related to the chemical and physical processes have been added to the total-cell model to account for an extra relaxation process in the spectra not measured at either electrode. The processes to which elements are attributed have been deduced by varying cell temperature, load current, and hydrogen concentration. Spectra data were also obtained for a planar stack of five 61 cm2 cells and the individual cells therein, which were fitted to a simplified equivalent circuit model of the total button cell. Similar to the button cell, the planar cells and stack exhibit a pronounced low-frequency relaxation process, which has been attributed to concentration losses, that is, the combined effects of diffusion and gas conversion. The simplified total-cell model approximates well the dynamic behavior of the SOFC cells and the whole stack.

  5. Characterization of atomic spin polarization lifetime of cesium vapor cells with neon buffer gas

    Science.gov (United States)

    Lou, Janet W.; Cranch, Geoffrey A.

    2018-02-01

    The dephasing time of spin-polarized atoms in an atomic vapor cell plays an important role in determining the stability of vapor-cell clocks as well as the sensitivity of optically-pumped magnetometers. The presence of a buffer gas can extend the lifetime of these atoms. Many vapor cell systems operate at a fixed (often elevated) temperature. For ambient temperature operation with no temperature control, it is necessary to characterize the temperature dependence as well. We present a spin-polarization lifetime study of Cesium vapor cells with different buffer gas pressures, and find good agreement with expectations based on the combined effects of wall collisions, spin exchange, and spin destruction. For our (7.5 mm diameter) vapor cells, the lifetime can be increased by two orders of magnitude by introducing Ne buffer gas up to 100 Torr. Additionally, the dependence of the lifetime on temperature is measured (25 - 47 oC) and simulated for the first time to our knowledge with reasonable agreement.

  6. Design of the gas cell for the IGISOL facility at ELI-NP

    Energy Technology Data Exchange (ETDEWEB)

    Constantin, P., E-mail: paul.constantin@eli-np.ro [Extreme Light Infrastructure – Nuclear Physics, “Horia Hulubei” National Institute for Physics and Nuclear Engineering, Str. Reactorului 30, 077125 Bucharest Magurele (Romania); Balabanski, D.L. [Extreme Light Infrastructure – Nuclear Physics, “Horia Hulubei” National Institute for Physics and Nuclear Engineering, Str. Reactorului 30, 077125 Bucharest Magurele (Romania); Anh, L.T. [Extreme Light Infrastructure – Nuclear Physics, “Horia Hulubei” National Institute for Physics and Nuclear Engineering, Str. Reactorului 30, 077125 Bucharest Magurele (Romania); Graduate University of Science and Technology, Vietnam Academy of Science and Technology, Hanoi (Viet Nam); Cuong, P.V. [Extreme Light Infrastructure – Nuclear Physics, “Horia Hulubei” National Institute for Physics and Nuclear Engineering, Str. Reactorului 30, 077125 Bucharest Magurele (Romania); Centre of Nuclear Physics, Institute of Physics, Vietnam Academy of Science and Technology, Hanoi (Viet Nam); Mei, B. [Extreme Light Infrastructure – Nuclear Physics, “Horia Hulubei” National Institute for Physics and Nuclear Engineering, Str. Reactorului 30, 077125 Bucharest Magurele (Romania)

    2017-04-15

    One of the experimental programs that will be carried out at the Extreme Light Infrastructure – Nuclear Physics (ELI-NP) facility is the production of exotic neutron-rich ion beams in an IGISOL facility via photofission in a stack of actinide targets placed at the center of a cell filled with He gas. Simulations with the Geant4 toolkit were done for the optimization of the target configuration that maximizes the rate of released photofission fragments. The cell geometry is established based on the stopping properties of these fragments. Studies, based on simulations with Geant4 and SIMION 8.1, of the space charge effect and its induced electric field in the gas cell are presented. Estimates of the extraction time and efficiency of the photofission fragments are derived.

  7. Modeling of proton exchange membrane fuel cell with variable distance gas flow in anode and cathode

    International Nuclear Information System (INIS)

    Mohd Shahbudin Masdar; Wan Ramli Wan Daud; Kamaruzzaman Sopian; Jaafar Sahari

    2006-01-01

    A number of fundamental studies have been directed towards increasing our understanding of PEM fuel cell and their performance. Mathematical modeling is one of the way and very essential component in the development of this fuel cell. Model validation is presented, the validated model is then used to investigate the behavior of mole fraction of gases, current density, and the performances of stack using polarization curve depending on distance gases flow in channel. The model incorporates a complete cell with both the membrane electrode assembly (MEA) and the serpentine gas distributor channel. Finally, the parametric studies in single stack design are illustrated

  8. High temperature and high pressure gas cell for quantitative spectroscopic measurements

    DEFF Research Database (Denmark)

    Christiansen, Caspar; Stolberg-Rohr, Thomine; Fateev, Alexander

    2016-01-01

    A high temperature and high pressure gas cell (HTPGC) has been manufactured for quantitative spectroscopic measurements in the pressure range 1-200 bar and temperature range 300-1300 K. In the present work the cell was employed at up to 100 bar and 1000 K, and measured absorption coefficients...... of a CO2-N2 mixture at 100 bar and 1000 K are revealed for the first time, exceeding the high temperature and pressure combinations previously reported. This paper discusses the design considerations involved in the construction of the cell and presents validation measurements compared against simulated...

  9. U^{28+}-intensity record applying a H_{2}-gas stripper cell

    Directory of Open Access Journals (Sweden)

    Winfried Barth

    2015-04-01

    Full Text Available To meet the Facility for Antiproton and Ion Research science requirements higher beam intensity has to be achieved in the present GSI-accelerator complex. For this an advanced upgrade program for the UNILAC is ongoing. Stripping is a key technology for all heavy ion accelerators. For this an extensive research and development program was carried out to optimize for high brilliance heavy ion operation. After upgrade of the supersonic N_{2}-gas jet (2007, implementation of high current foil stripping (2011 and preliminary investigation of H_{2}-gas jet operation (2012, recently (2014 a new H_{2}-gas cell using a pulsed gas regime synchronized with arrival of the beam pulse has been developed. An obviously enhanced stripper gas density as well as a simultaneously reduced gas load for the pumping system result in an increased stripping efficiency, while the beam emittance remains the same. A new record intensity (7.8 emA for ^{238}U^{28+} beams at 1.4  MeV/u has been achieved applying the pulsed high density H_{2} stripper target to a high intensity ^{238}U^{4+} beam from the VARIS ion source with a newly developed extraction system. The experimental results are presented in detail.

  10. In-gas-cell laser ionization studies of plutonium isotopes at IGISOL

    International Nuclear Information System (INIS)

    Pohjalainen, I.; Moore, I.D.; Kron, T.; Raeder, S.; Sonnenschein, V.; Tomita, H.; Trautmann, N.; Voss, A.; Wendt, K.

    2016-01-01

    In-gas-cell resonance laser ionization has been performed on long-lived isotopes of Pu at the IGISOL facility, Jyväskylä. This initiates a new programme of research towards high-resolution optical spectroscopy of heavy actinide elements which can be produced in sufficient quantities at research reactors and transported to facilities elsewhere. In this work a new gas cell has been constructed for fast extraction of laser-ionized elements. Samples of "2"3"8"–"2"4"0","2"4"2Pu and "2"4"4Pu have been evaporated from Ta filaments, laser ionized, mass separated and delivered to the collinear laser spectroscopy station. Here we report on the performance of the gas cell through studies of the mass spectra obtained in helium and argon, before and after the radiofrequency quadrupole cooler-buncher. This provides valuable insight into the gas phase chemistry exhibited by Pu, which has been additionally supported by measurements of ion time profiles. The resulting monoatomic yields are sufficient for collinear laser spectroscopy. A gamma-ray spectroscopic analysis of the Pu samples shows a good agreement with the assay provided by the Mainz Nuclear Chemistry department.

  11. High-pressure measuring cell for Raman spectroscopic studies of natural gas

    DEFF Research Database (Denmark)

    Hansen, Susanne Brunsgaard; Berg, Rolf W.; Stenby, Erling Halfdan

    2001-01-01

    A system for obtaining Raman spectra of gases at high pressure has been constructed. In order to ensure that a natural gas sample is totally representative, a high-pressure gas-measuring cell has been developed, built up by stainless steel fittings and a sapphire tube. The design and construction...... of this cell are described. A perfect pressure seal has been demonstrated up to 15.0 MPaA (MPa absolute). The cell has been successfully used to obtain Raman spectra of natural gas samples. Some of these spectra are presented and assigned. The most remarkable observation in the spectra is that it is possible...... to detect hydrogen sulfide at concentrations of 1-3 mg H2S/Nm(3). An attempt to make a quantitative analysis of natural gas by the so-called "ratio method" is presented. In addition to this, the relative normalized differential Raman scattering cross sections for ethane and i-butane molecules at 8.0 MPa...

  12. In-gas-cell laser ionization studies of plutonium isotopes at IGISOL

    Science.gov (United States)

    Pohjalainen, I.; Moore, I. D.; Kron, T.; Raeder, S.; Sonnenschein, V.; Tomita, H.; Trautmann, N.; Voss, A.; Wendt, K.

    2016-06-01

    In-gas-cell resonance laser ionization has been performed on long-lived isotopes of Pu at the IGISOL facility, Jyväskylä. This initiates a new programme of research towards high-resolution optical spectroscopy of heavy actinide elements which can be produced in sufficient quantities at research reactors and transported to facilities elsewhere. In this work a new gas cell has been constructed for fast extraction of laser-ionized elements. Samples of 238-240,242Pu and 244Pu have been evaporated from Ta filaments, laser ionized, mass separated and delivered to the collinear laser spectroscopy station. Here we report on the performance of the gas cell through studies of the mass spectra obtained in helium and argon, before and after the radiofrequency quadrupole cooler-buncher. This provides valuable insight into the gas phase chemistry exhibited by Pu, which has been additionally supported by measurements of ion time profiles. The resulting monoatomic yields are sufficient for collinear laser spectroscopy. A gamma-ray spectroscopic analysis of the Pu samples shows a good agreement with the assay provided by the Mainz Nuclear Chemistry department.

  13. Electricity generation from synthesis gas by microbial processes: CO fermentation and microbial fuel cell technology.

    Science.gov (United States)

    Kim, Daehee; Chang, In Seop

    2009-10-01

    A microbiological process was established to harvest electricity from the carbon monoxide (CO). A CO fermenter was enriched with CO as the sole carbon source. The DGGE/DNA sequencing results showed that Acetobacterium spp. were enriched from the anaerobic digester fluid. After the fermenter was operated under continuous mode, the products were then continuously fed to the microbial fuel cell (MFC) to generate electricity. Even though the conversion yield was quite low, this study proved that synthesis gas (syn-gas) can be converted to electricity with the aid of microbes that do not possess the drawbacks of metal catalysts of conventional methods.

  14. Avidin-biotin-based approach to forming heterotypic cell clusters and cell sheets on a gas-permeable membrane

    Energy Technology Data Exchange (ETDEWEB)

    Hamon, M; Ozawa, T; Montagne, K; Kojima, N; Ishii, R; Sakai, Y [Institute of Industrial Science (IIS), University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505 (Japan); Yamaguchi, S; Nagamune, T [Department of Bioengineering, Graduate School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Ushida, T, E-mail: mzh0026@auburn.edu [Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2011-09-15

    Implantation of sheet-like liver tissues is a promising method in hepatocyte-based therapies, because angiogenesis is expected to occur upon implantation from the surrounding tissues. In this context, we introduce here a new methodology for the formation of a functional thick hepatic tissue usable for cell sheet technology. First, we report the formation of composite tissue elements in suspension culture. Composite elements were composed of human hepatoma Hep G2 cells and mouse NIH/3T3 fibroblasts which are important modulators for thick-tissue formation. To overcome the very low attachment and organization capability between different cells in suspension, we synthesized a new cell-to-cell binding molecule based on the avidin-biotin binding system that we previously applied to attach hepatocytes on artificial substrata. This newly synthesized biotin-conjugated biocompatible anchoring molecule was inserted in the plasma membrane of both cell types. NIH/3T3 cells were further conjugated with avidin and incubated with biotin-presenting Hep G2 cells to form highly composite tissue elements. Then, we seeded those elements on highly gas-permeable membranes at their closest packing density to induce the formation of a thick, composite, functional hepatic tissue without any perfusion. This methodology could open a new way to engineer implantable thick liver tissue sheets where different cell types are spatially organized and well supplied with oxygen.

  15. Local area water removal analysis of a proton exchange membrane fuel cell under gas purge conditions.

    Science.gov (United States)

    Lee, Chi-Yuan; Lee, Yu-Ming; Lee, Shuo-Jen

    2012-01-01

    In this study, local area water content distribution under various gas purging conditions are experimentally analyzed for the first time. The local high frequency resistance (HFR) is measured using novel micro sensors. The results reveal that the liquid water removal rate in a membrane electrode assembly (MEA) is non-uniform. In the under-the-channel area, the removal of liquid water is governed by both convective and diffusive flux of the through-plane drying. Thus, almost all of the liquid water is removed within 30 s of purging with gas. However, liquid water that is stored in the under-the-rib area is not easy to remove during 1 min of gas purging. Therefore, the re-hydration of the membrane by internal diffusive flux is faster than that in the under-the-channel area. Consequently, local fuel starvation and membrane degradation can degrade the performance of a fuel cell that is started from cold.

  16. Control oriented modeling of ejector in anode gas recirculation solid oxygen fuel cell systems

    International Nuclear Information System (INIS)

    Zhu Yinhai; Li Yanzhong; Cai Wenjian

    2011-01-01

    A one-equation model is proposed for fuel ejector in anode gas recirculation solid oxide fuel cell (SOFC) system. Firstly, the fundamental governing equations are established by employing the thermodynamic, fluid dynamic principles and chemical constraints inside the ejector; secondly, the one-equation model is derived by using the parameter analysis and lumped-parameter method. Finally, the computational fluid dynamics (CFD) technique is employed to obtain the source data for determining the model parameters. The effectiveness of the model is studied under a wide range of operation conditions. The effect of ejector performance on the anode gas recirculation SOFC system is also discussed. The presented model, which only contains four constant parameters, is useful in real-time control and optimization of fuel ejector in the anode gas recirculation SOFC system.

  17. High pressure operation of tubular solid oxide fuel cells and their intergration with gas turbines

    Energy Technology Data Exchange (ETDEWEB)

    Haynes, C.; Wepfer, W.J. [Georgia Institute of Technology, Atlanta, GA (United States)

    1996-12-31

    Fossil fuels continue to be used at a rate greater than that of their natural formation, and the current byproducts from their use are believed to have a detrimental effect on the environment (e.g. global warming). There is thus a significant impetus to have cleaner, more efficient fuel consumption alternatives. Recent progress has led to renewed vigor in the development of fuel cell technology, which has been shown to be capable of producing high efficiencies with relatively benign exhaust products. The tubular solid oxide fuel cell developed by Westinghouse Electric Corporation has shown significant promise. Modeling efforts have been and are underway to optimize and better understand this fuel cell technology. Thus far, the bulk of modeling efforts has been for operation at atmospheric pressure. There is now interest in developing high-efficiency integrated gas turbine/solid oxide fuel cell systems. Such operation of fuel cells would obviously occur at higher pressures. The fuel cells have been successfully modeled under high pressure operation and further investigated as integrated components of an open loop gas turbine cycle.

  18. Genealogy of gas cells for low-energy RI-beam production

    Energy Technology Data Exchange (ETDEWEB)

    Wada, Michiharu, E-mail: mw@riken.jp

    2013-12-15

    Highlights: • In order to overcome serious limitations in the universality of the traditional isotope separator on-line technique, various endeavors have been made on gas catcher cells for converting relativistic RI-beams from in-flight separators to low-energy RI-beams. • The origin of the gas catcher is found in the IGISOL (Ion guide isotope separator on-line) technique. • Many developments have been made over the years to overcome the various difficulties and drawbacks found in the IGISOL technique. -- Abstract: In order to overcome serious limitations in the universality of the traditional isotope separator on-line technique, various endeavors have been made on gas catcher cells for converting relativistic RI-beams from in-flight separators to low-energy RI-beams. The origin of the gas catcher is found in the IGISOL (Ion guide isotope separator on-line) technique. Many developments have been made over the years to overcome the various difficulties and drawbacks found in the IGISOL technique.

  19. Genealogy of gas cells for low-energy RI-beam production

    International Nuclear Information System (INIS)

    Wada, Michiharu

    2013-01-01

    Highlights: • In order to overcome serious limitations in the universality of the traditional isotope separator on-line technique, various endeavors have been made on gas catcher cells for converting relativistic RI-beams from in-flight separators to low-energy RI-beams. • The origin of the gas catcher is found in the IGISOL (Ion guide isotope separator on-line) technique. • Many developments have been made over the years to overcome the various difficulties and drawbacks found in the IGISOL technique. -- Abstract: In order to overcome serious limitations in the universality of the traditional isotope separator on-line technique, various endeavors have been made on gas catcher cells for converting relativistic RI-beams from in-flight separators to low-energy RI-beams. The origin of the gas catcher is found in the IGISOL (Ion guide isotope separator on-line) technique. Many developments have been made over the years to overcome the various difficulties and drawbacks found in the IGISOL technique

  20. Gas driven displacement in a Hele-Shaw cell with chemical reaction

    Science.gov (United States)

    White, Andrew; Ward, Thomas

    2011-11-01

    Injecting a less viscous fluid into a more viscous fluid produces instabilities in the form of fingering which grow radially from the less viscous injection point (Saffman & Taylor, Proc. R. Soc. Lon. A, 1958). For two non-reacting fluids in a radial Hele-Shaw cell the ability of the gas phase to penetrate the liquid phase is largely dependent on the gap height, liquid viscosity and gas pressure. In contrast combining two reactive fluids such as aqueous calcium hydroxide and carbon dioxide, which form a precipitate, presents a more complex but technically relevant system. As the two species react calcium carbonate precipitates and increases the aqueous phase visocosity. This change in viscosity may have a significant impact on how the gas phase penetrates the liquid phase. Experimental are performed in a radial Hele-Shaw cell with gap heights O(10-100) microns by loading a single drop of aqueous calcium hydroxide and injecting carbon dioxide into the drop. The calcium hydroxide concentration, carbon dioxide pressure and gap height are varied and images of the gas penetration are analyzed to determine residual film thickness and bursting times.

  1. Modified gas diffusion layer for fuel cells synthesized by pulsed laser ablation

    International Nuclear Information System (INIS)

    Ebrasu, Daniela; Stefanescu, Ioan; Dorcioman, Gabriela; Serban, Nicolae; Axente, Emil; Sima, Felix; Ristoscu, Carmen; Mihailescu, Ioan N.; Enculescu, Ionut

    2010-01-01

    Full text; In this paper there are presented the first results regarding the development of a modified gas diffusion layer for fuel cells consisting of a simple or teflonized carbon cloth deposited by pulsed laser with metal oxide nanostructures. These are designed to operate both as co-catalyst, and oxidic support for other electrochemically active catalysts. We selected TiO 2 , ZnO and Al 2 O 3 doped (2 wt.%) ZnO which were uniformly distributed over the surface of gas diffusion layers in order to improve the catalytic activity, stability and lifetime, and reduce the production costs of proton exchange membrane fuel cells. We evidenced by scanning electron microscopy and energy dispersive spectroscopy that our depositions consisted of TiO 2 nanoparticles while in the case of ZnO and Al 2 O 3 doped (2 wt.%) ZnO transparent quasicontinuous films were synthesized. (authors)

  2. A recoverable gas-cell diagnostic for the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Ratkiewicz, A., E-mail: ratkiewicz1@llnl.gov; Berzak Hopkins, L.; Bleuel, D. L.; Cassata, W. S.; Velsko, C. A.; Yeamans, C. B. [Lawrence Livermore National Laboratory, Livermore, California 95440 (United States); Bernstein, L. A.; Bibber, K. van; Goldblum, B. L. [University of California, Berkeley, California 94720 (United States); Siem, S. [University of Oslo, N-0316 Oslo (Norway); Wiedeking, M. [iThemba LABS, Somerset West 7129 (South Africa)

    2016-11-15

    The high-fluence neutron spectrum produced by the National Ignition Facility (NIF) provides an opportunity to measure the activation of materials by fast-spectrum neutrons. A new large-volume gas-cell diagnostic has been designed and qualified to measure the activation of gaseous substances at the NIF. This in-chamber diagnostic is recoverable, reusable and has been successfully fielded. Data from the qualification of the diagnostic have been used to benchmark an Monte Carlo N-Particle Transport Code simulation describing the downscattered neutron spectrum seen by the gas cell. We present early results from the use of this diagnostic to measure the activation of {sup nat}Xe and discuss future work to study the strength of interactions between plasma and nuclei.

  3. A recoverable gas-cell diagnostic for the National Ignition Facility.

    Science.gov (United States)

    Ratkiewicz, A; Berzak Hopkins, L; Bleuel, D L; Bernstein, L A; van Bibber, K; Cassata, W S; Goldblum, B L; Siem, S; Velsko, C A; Wiedeking, M; Yeamans, C B

    2016-11-01

    The high-fluence neutron spectrum produced by the National Ignition Facility (NIF) provides an opportunity to measure the activation of materials by fast-spectrum neutrons. A new large-volume gas-cell diagnostic has been designed and qualified to measure the activation of gaseous substances at the NIF. This in-chamber diagnostic is recoverable, reusable and has been successfully fielded. Data from the qualification of the diagnostic have been used to benchmark an Monte Carlo N-Particle Transport Code simulation describing the downscattered neutron spectrum seen by the gas cell. We present early results from the use of this diagnostic to measure the activation of nat Xe and discuss future work to study the strength of interactions between plasma and nuclei.

  4. Computer experiments on ion beam cooling and guiding in fair-wind gas cell and extraction RF-funnel system

    International Nuclear Information System (INIS)

    Varentsov, Victor; Wada, Michiharu

    2004-01-01

    Here we present results of the further development of two novel ideas in the field of slow RI-beams production. They are a fair-wind gas cell concept for big-size high-pressure buffer gas cells and a new approach to the extraction system. For this purpose, detailed gas dynamic simulations based on the solution of a full system of time-dependent Navier-Stokes equations have been performed for both the fair-wind gas cell of 500 mm length at 1 bar helium buffer gas pressure and the RF-funnel extraction system at low buffer gas pressure. The results of gas dynamic calculations were used for detailed microscopic Monte Carlo ion-beam trajectory simulations under the combined effect of the buffer gas flow and electric fields of the RF-funnels. The obtained results made it apparent that the use of the fair-wind gas cell concept and extraction RF-funnels look very promising for production of high-quality low-energy RI-beams

  5. Performance of a parallel plate volume cell prototype for a fast iron/gas calorimeter

    International Nuclear Information System (INIS)

    Bizzeti, A.; Civinini, C.; D'alessandro, R.; Ferrando, A.

    1993-01-01

    We present the first test of the application of the parallel plate chamber principles for the design of a very fast and radiation-hard iron/gas sampling calorimeter, suitable for very forward regions in detectors for LBC; based on the use of thick iron plates as electrodes. We have built a one cell prototype consisting of three parallel thick iron plates (117 mn each). Results on efficiencies and mean collected charge for minimum ionizing particles with different gases are presented. (Author)

  6. Dynamic modeling of gas turbines in integrated gasification fuel cell systems

    Science.gov (United States)

    Maclay, James Davenport

    2009-12-01

    Solid oxide fuel cell-gas turbine (SOFC-GT) hybrid systems for use in integrated gasification fuel cell (IGFC) systems operating on coal will stretch existing fossil fuel reserves, generate power with less environmental impact, while having a cost of electricity advantage over most competing technologies. However, the dynamic performance of a SOFC-GT in IGFC applications has not been previously studied in detail. Of particular importance is how the turbo-machinery will be designed, controlled and operated in such applications; this is the focus of the current work. Perturbation and dynamic response analyses using numerical SimulinkRTM models indicate that compressor surge is the predominant concern for safe dynamic turbo-machinery operation while shaft over-speed and excessive turbine inlet temperatures are secondary concerns. Fuel cell temperature gradients and anode-cathode differential pressures were found to be the greatest concerns for safe dynamic fuel cell operation. Two control strategies were compared, that of constant gas turbine shaft speed and constant fuel cell temperature, utilizing a variable speed gas turbine. Neither control strategy could eliminate all vulnerabilities during dynamic operation. Constant fuel cell temperature control ensures safe fuel cell operation, while constant speed control does not. However, compressor surge is more likely with constant fuel cell temperature control than with constant speed control. Design strategies that provide greater surge margin while utilizing constant fuel cell temperature control include increasing turbine design mass flow and decreasing turbine design inlet pressure, increasing compressor design pressure ratio and decreasing compressor design mass flow, decreasing plenum volume, decreasing shaft moment of inertia, decreasing fuel cell pressure drop, maintaining constant compressor inlet air temperature. However, these strategies in some cases incur an efficiency penalty. A broad comparison of cycles

  7. Phase matching of high-order harmonics in a semi-infinite gas cell

    International Nuclear Information System (INIS)

    Steingrube, Daniel S.; Vockerodt, Tobias; Schulz, Emilia; Morgner, Uwe; Kovacev, Milutin

    2009-01-01

    Phase matching of high-order harmonic generation is investigated experimentally for various parameters in a semi-infinite gas-cell (SIGC) geometry. The optimized harmonic yield is identified using two different noble gases (Xe and He) and its parameter dependence is studied in a systematic way. Beside the straightforward setup of the SIGC, this geometry promises a high photon flux due to a large interaction region. Moreover, since the experimental parameters within this cell are known accurately, direct comparison to simulations is performed. Spectral splitting and blueshift of high-order harmonics are observed.

  8. Hydrogen from biomass gas steam reforming for low temperature fuel cell: energy and exergy analysis

    Directory of Open Access Journals (Sweden)

    A. Sordi

    2009-03-01

    Full Text Available This work presents a method to analyze hydrogen production by biomass gasification, as well as electric power generation in small scale fuel cells. The proposed methodology is the thermodynamic modeling of a reaction system for the conversion of methane and carbon monoxide (steam reforming, as well as the energy balance of gaseous flow purification in PSA (Pressure Swing Adsorption is used with eight types of gasification gases in this study. The electric power is generated by electrochemical hydrogen conversion in fuel cell type PEMFC (Proton Exchange Membrane Fuel Cell. Energy and exergy analyses are applied to evaluate the performance of the system model. The simulation demonstrates that hydrogen production varies with the operation temperature of the reforming reactor and with the composition of the gas mixture. The maximum H2 mole fraction (0.6-0.64 mol.mol-1 and exergetic efficiency of 91- 92.5% for the reforming reactor are achieved when gas mixtures of higher quality such as: GGAS2, GGAS4 and GGAS5 are used. The use of those gas mixtures for electric power generation results in lower irreversibility and higher exergetic efficiency of 30-30.5%.

  9. Fuel cell-gas turbine hybrid system design part II: Dynamics and control

    Science.gov (United States)

    McLarty, Dustin; Brouwer, Jack; Samuelsen, Scott

    2014-05-01

    Fuel cell gas turbine hybrid systems have achieved ultra-high efficiency and ultra-low emissions at small scales, but have yet to demonstrate effective dynamic responsiveness or base-load cost savings. Fuel cell systems and hybrid prototypes have not utilized controls to address thermal cycling during load following operation, and have thus been relegated to the less valuable base-load and peak shaving power market. Additionally, pressurized hybrid topping cycles have exhibited increased stall/surge characteristics particularly during off-design operation. This paper evaluates additional control actuators with simple control methods capable of mitigating spatial temperature variation and stall/surge risk during load following operation of hybrid fuel cell systems. The novel use of detailed, spatially resolved, physical fuel cell and turbine models in an integrated system simulation enables the development and evaluation of these additional control methods. It is shown that the hybrid system can achieve greater dynamic response over a larger operating envelope than either individual sub-system; the fuel cell or gas turbine. Results indicate that a combined feed-forward, P-I and cascade control strategy is capable of handling moderate perturbations and achieving a 2:1 (MCFC) or 4:1 (SOFC) turndown ratio while retaining >65% fuel-to-electricity efficiency, while maintaining an acceptable stack temperature profile and stall/surge margin.

  10. Electrochemical cell with integrated hydrocarbon gas sensor for automobile exhaust gas; Elektrochemische Zelle mit integriertem Kohlenwasserstoff-Gassensor fuer das Automobilabgas

    Energy Technology Data Exchange (ETDEWEB)

    Biskupski, D.; Moos, R. [Univ. Bayreuth (Germany). Bayreuth Engine Research Center, Lehrstuhl fuer Funktionsmaterialien; Wiesner, K.; Fleischer, M. [Siemens AG, Corporate Technology, CT PS 6, Muenchen (Germany)

    2007-07-01

    In the future sensors will be necessary to control the compliance with hydrocarbon limiting values, allowing a direct detection of the hydrocarbons. Appropriate sensor-active functional materials are metal oxides, which have a hydrocarbon sensitivity but are also dependent on the oxygen partial pressure. It is proposed that the gas-sensing layer should be integrated into an electrochemical cell. The authors show that the integration of a resistive oxygen sensor into a pump cell allows a defined oxygen concentration level at the sensor layer in any exhaust gas.

  11. Design of a tritium gas cell for beta-ray induced X-ray spectrometry using Monte Carlo simulation

    Energy Technology Data Exchange (ETDEWEB)

    Hara, Masanori, E-mail: masahara@ctg.u-toyama.ac.jp [Hydrogen Isotope Research Center, Organization for Promotion of Research, University of Toyama, 3190 Gofuku, Toyama City, Toyama 930-8555 (Japan); Abe, Shinsuke; Matsuyama, Masao [Hydrogen Isotope Research Center, Organization for Promotion of Research, University of Toyama, 3190 Gofuku, Toyama City, Toyama 930-8555 (Japan); Aso, Tsukasa [Electronics and Computer Engineering, National Institute of Technology, Toyama College, 1-2 Ebie-neriya, Imizu City, Toyama 933-0293 (Japan); Tatenuma, Katsuyoshi; Kawakami, Tomohiko; Ito, Takeshi [KAKEN Company Limited, 1044 Horimachi, Mito City, Ibaraki 310-0903 (Japan)

    2017-06-15

    Highlights: • Beta-ray induced X-ray spectrometry (BIXS) is a method for tritium gas analysis. • Gas cell for BIXS was designed by Monte Carlo simulations. • The optimum thickness of the gold layer on a beryllium window was around 150 nm. • This simulation model considered the self-absorption with increasing the cell length. - Abstract: One of the methods used for tritium gas analysis is beta-ray induced X-ray spectrometry (BIXS). Gas cell design is important in this method. The structure of the gas cell for BIXS was optimized by Monte Carlo simulation of beta-ray induced X-ray spectra in various window geometries using the Geant4 tool kit (version 10.01.p02). The simulated spectrum from tritium decay fitted the observed one, and the simulation model was used to obtain the cell parameters for BIXS. The optimum thickness of the gold layer on a beryllium window was around 150 nm. This simulation model also considered the relationship between self-absorption by hydrogen gas and the cell length. Self-absorption increased with increasing cell length and the relationship between the sample pressure and cell length was formulated.

  12. X-ray burst studies with the JENSA gas jet target

    Directory of Open Access Journals (Sweden)

    Schmidt Konrad

    2017-01-01

    Full Text Available When a neutron star accretes hydrogen and helium from the outer layers of its companion star, thermonuclear burning enables the αp-process as a break out mechanism from the hot CNO cycle. Model calculations predict (α, p reaction rates significantly affect both the light curves and elemental abundances in the burst ashes. The Jet Experiments in Nuclear Structure and Astrophysics (JENSA gas jet target enables the direct measurement of previously inaccessible (α,p reactions with radioactive beams provided by the rare isotope re-accelerator ReA3 at the National Superconducting Cyclotron Laboratory (NSCL, USA. JENSA is going to be the main target for the Recoil Separator for Capture Reactions (SECAR at the Facility for Rare Isotope Beams (FRIB. Commissioning of JENSA and first experiments at Oak Ridge National Laboratory (ORNL showed a highly localized, pure gas target with a density of ∼1019 atoms per square centimeter. Preliminary results are presented from the first direct cross section measurement of the 34Ar(α, p37 K reaction at NSCL.

  13. The effects of UV irradiation and gas plasma treatment on living mammalian cells and bacteria: a comparative approach

    NARCIS (Netherlands)

    Sosnin, E.A.; Stoffels - Adamowicz, E.; Erofeev, M.V.; Kieft, I.E.; Kunts, S.E.

    2004-01-01

    Living mammalian cells and bacteria were exposed to irradiation from narrow-band UV lamps and treated with a nonthermal gas plasma (plasma needle). The model systems were: Chinese Hamster Ovary (CHO-K1) cells (fibroblasts) and Escherichia Coli bacteria. UV irradiation can lead to cell death

  14. Predicting liquid water saturation through differently structured cathode gas diffusion media of a proton exchange Membrane Fuel Cell

    NARCIS (Netherlands)

    Akhtar, N.; Kerkhof, P.J.A.M.

    2012-01-01

    The role of gas diffusion media with differently structured properties have been examined with emphasis on the liquid water saturation within the cathode of a proton exchange membrane fuel cell (PEMFC). The cathode electrode consists of a gas diffusion layer (GDL), a micro-porous layer and a

  15. Effect of cathode gas humidification on performance and durability of Solid Oxide Fuel Cells

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Hagen, Anke; Liu, Yi-Lin

    2010-01-01

    The effect of cathode inlet gas humidification was studied on single anode supported Solid Oxide Fuel Cells (SOFC's). The studied cells were Risø 2 G and 2.5 G. The former consists of a LSM:YSZ composite cathode, while the latter consists of a LSCF:CGO composite cathode on a CGO protection layer....... The humidification effect was found to be dependent on both the degree of humidification and the cathode polarization. No significant effect of humidification was found at OCV which rules out the possibility of a traditional poisoning effect with a blocking of active sites. Post-mortem high resolution FEG......-SEM analysis showed clear changes at and around the cathode/electrolyte contact area. In contrast to Risø 2 G cells, a very high tolerance towards humidification of cathode gas air was observed for Risø 2.5 G cells with no detectable effect of humidification even when the humidification was as high as 12.8 mol%...

  16. Microbial Electrodialysis Cell for Simultaneous Water Desalination and Hydrogen Gas Production

    KAUST Repository

    Mehanna, Maha; Kiely, Patrick D.; Call, Douglas F.; Logan, Bruce. E.

    2010-01-01

    A new approach to water desalination is to use exoelectrogenic bacteria to generate electrical power from the biodegradation of organic matter, moving charged ions from a middle chamber between two membranes in a type of microbial fuel cell called a microbial desalination cell. Desalination efficiency using this approach is limited by the voltage produced by the bacteria. Here we examine an alternative strategy based on boosting the voltage produced by the bacteria to achieve hydrogen gas evolution from the cathode using a three-chambered system we refer to as a microbial electrodialysis cell (MEDC). We examined the use of the MEDC process using two different initial NaCl concentrations of 5 g/L and 20 g/L. Conductivity in the desalination chamber was reduced by up to 68 ± 3% in a single fed-batch cycle, with electrical energy efficiencies reaching 231 ± 59%, and maximum hydrogen production rates of 0.16 ± 0.05 m3 H2/m3 d obtained at an applied voltage of 0.55 V. The advantage of this system compared to a microbial fuel cell approach is that the potentials between the electrodes can be better controlled, and the hydrogen gas that is produced can be used to recover energy to make the desalination process self-sustaining with respect to electrical power requirements. © 2010 American Chemical Society.

  17. Microbial Electrodialysis Cell for Simultaneous Water Desalination and Hydrogen Gas Production

    KAUST Repository

    Mehanna, Maha

    2010-12-15

    A new approach to water desalination is to use exoelectrogenic bacteria to generate electrical power from the biodegradation of organic matter, moving charged ions from a middle chamber between two membranes in a type of microbial fuel cell called a microbial desalination cell. Desalination efficiency using this approach is limited by the voltage produced by the bacteria. Here we examine an alternative strategy based on boosting the voltage produced by the bacteria to achieve hydrogen gas evolution from the cathode using a three-chambered system we refer to as a microbial electrodialysis cell (MEDC). We examined the use of the MEDC process using two different initial NaCl concentrations of 5 g/L and 20 g/L. Conductivity in the desalination chamber was reduced by up to 68 ± 3% in a single fed-batch cycle, with electrical energy efficiencies reaching 231 ± 59%, and maximum hydrogen production rates of 0.16 ± 0.05 m3 H2/m3 d obtained at an applied voltage of 0.55 V. The advantage of this system compared to a microbial fuel cell approach is that the potentials between the electrodes can be better controlled, and the hydrogen gas that is produced can be used to recover energy to make the desalination process self-sustaining with respect to electrical power requirements. © 2010 American Chemical Society.

  18. Investigation of the Electron Acceleration by a High-Power Laser and a Density-Tapered Mixed-Gas Cell

    Science.gov (United States)

    Kim, Jinju; Phung, Vanessa L. J.; Kim, Minseok; Hur, Min-Sup; Suk, Hyyong

    2017-10-01

    Plasma-based accelerators can generate about 1000 times stronger acceleration field compared with RF-based conventional accelerators, which can be done by high power laser and plasma. There are many issues in this research and one of them is development of a good plasma source for higher electron beam energy. For this purpose, we are investigating a special type of plasma source, which is a density-tapered gas cell with a mixed-gas for easy injection. By this type of special gas cell, we expect higher electron beam energies with easy injection in the wakefield. In this poster, some experimental results for electron beam generation with the density-tapered mixed-gas cell are presented. In addition to the experimental results, CFD (Computational-Fluid-Dynamics) and PIC (Particle-In-Cell) simulation results are also presented for comparison studies.

  19. Investigation of gas flow characteristics in proton exchange membrane fuel cell

    International Nuclear Information System (INIS)

    Kwac, Lee Ku; Kim, Hong Gun

    2008-01-01

    An investigation of electrochemical behavior of PEMFC (proton exchange membrane fuel cell) is performed by using a single-phase two-dimensional finite element analysis. Equations of current balance, mass balance, and momentum balance are implemented to simulate the behavior of PEMFC. The analysis results for the co-flow and counterflow mode of gas flow direction are examined in detail in order to compare how the gas flow direction affects quantitatively. The characteristics of internal properties, such as gas velocity distribution, mass fraction of the reactants, fraction of water and current density distribution in PEMFC are illustrated in the electrode and GDL (gas diffusion layer). It is found that the dry reactant gases can be well internally humidified and maintain high performance in the case of the counter-flow mode without external humidification while it is not advantageous for highly humidified or saturated reactant gases. It is also found that the co-flow mode improves the current density distribution with humidified normal condition compared to the counter-flow mode

  20. Gas diffusion layer for proton exchange membrane fuel cells - A review

    Energy Technology Data Exchange (ETDEWEB)

    Cindrella, L. [Fuel Cell Research Laboratory, Department of Engineering Technology, Arizona State University, Mesa, AZ 85212 (United States); Department of Chemistry, National Institute of Technology, Tiruchirappalli 620015 (India); Kannan, A.M.; Lin, J.F.; Saminathan, K. [Fuel Cell Research Laboratory, Department of Engineering Technology, Arizona State University, Mesa, AZ 85212 (United States); Ho, Y. [Department of Biotechnology, College of Health Science, Asia University, Taichung 41354 (China); Lin, C.W. [Department of Chemical Engineering, National Yunlin University of Science and Technology, Yunlin 640 (China); Wertz, J. [Hollingsworth and Vose Co., A.K. Nicholson Research Lab, 219 Townsend Road, West Groton, MA 01472 (United States)

    2009-10-20

    Gas diffusion layer (GDL) is one of the critical components acting both as the functional as well as the support structure for membrane-electrode assembly in the proton exchange membrane fuel cell (PEMFC). The role of the GDL is very significant in the H{sub 2}/air PEM fuel cell to make it commercially viable. A bibliometric analysis of the publications on the GDLs since 1992 shows a total of 400+ publications (>140 papers in the Journal of Power Sources alone) and reveals an exponential growth due to reasons that PEMFC promises a lot of potential as the future energy source for varied applications and hence its vital component GDL requires due innovative analysis and research. This paper is an attempt to pool together the published work on the GDLs and also to review the essential properties of the GDLs, the method of achieving each one of them, their characterization and the current status and future directions. The optimization of the functional properties of the GDLs is possible only by understanding the role of its key parameters such as structure, porosity, hydrophobicity, hydrophilicity, gas permeability, transport properties, water management and the surface morphology. This paper discusses them in detail to provide an insight into the structural parts that make the GDLs and also the processes that occur in the GDLs under service conditions and the characteristic properties. The required balance in the properties of the GDLs to facilitate the counter current flow of the gas and water is highlighted through its characteristics. (author)

  1. Optical Pumping Spin Exchange 3He Gas Cells for Magnetic Resonance Imaging

    Science.gov (United States)

    Kim, W.; Stepanyan, S. S.; Kim, A.; Jung, Y.; Woo, S.; Yurov, M.; Jang, J.

    2009-08-01

    We present a device for spin-exchange optical pumping system to produce large quantities of polarized noble gases for Magnetic Resonance Imaging (MRI). A method and design of apparatus for pumping the polarization of noble gases is described. The method and apparatus enable production, storage and usage of hyperpolarized noble gases for different purposes, including Magnetic Resonance Imaging of human and animal subjects. Magnetic imaging agents breathed into lungs can be observed by the radio waves of the MRI scanner and report back physical and functional information about lung's health and desease. The technique known as spin exchange optical pumping is used. Nuclear magnetic resonance is implemented to measure the polarization of hyperpolarized gas. The cells prepared and sealed under high vacuum after handling Alkali metals into the cell and filling with the 3He-N2 mixture. The cells could be refilled. The 3He reaches around 50% polarization in 5-15 hours.

  2. Liquid water breakthrough location distances on a gas diffusion layer of polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Yu, Junliang; Froning, Dieter; Reimer, Uwe; Lehnert, Werner

    2018-06-01

    The lattice Boltzmann method is adopted to simulate the three dimensional dynamic process of liquid water breaking through the gas diffusion layer (GDL) in the polymer electrolyte membrane fuel cell. 22 micro-structures of Toray GDL are built based on a stochastic geometry model. It is found that more than one breakthrough locations are formed randomly on the GDL surface. Breakthrough location distance (BLD) are analyzed statistically in two ways. The distribution is evaluated statistically by the Lilliefors test. It is concluded that the BLD can be described by the normal distribution with certain statistic characteristics. Information of the shortest neighbor breakthrough location distance can be the input modeling setups on the cell-scale simulations in the field of fuel cell simulation.

  3. Overproduction of individual gas vesicle proteins perturbs flotation, antibiotic production and cell division in the enterobacterium Serratia sp. ATCC 39006.

    Science.gov (United States)

    Monson, Rita E; Tashiro, Yosuke; Salmond, George P C

    2016-09-01

    Gas vesicles are intracellular proteinaceous organelles that facilitate bacterial colonization of static water columns. In the enterobacterium Serratia sp. ATCC 39006, gas vesicle formation requires the proteins GvpA1, GvpF1, GvpG, GvpA2, GvpK, GvpA3, GvpF2 and GvpF3 and the three gas vesicle regulatory proteins GvrA, GvrB and GvrC. Deletion of gvpC alters gas vesicle robustness and deletion of gvpN or gvpV results in small bicone vesicles. In this work, we assessed the impacts on gas vesicle formation when each of these 14 essential proteins was overexpressed. Overproduction of GvpF1, GvpF2, GvrA, GvrB or GvrC all resulted in significantly reduced gas vesicle synthesis. Perturbations in gas vesicle formation were also observed when GvpV and GvpA3 were in excess. In addition to impacts on gas vesicle formation, overproduction of GvrA or GvrB led to elevated biosynthesis of the tripyrrole pigment, prodigiosin, a secondary metabolite of increasing medical interest due to its antimalarial and anticancer properties. Finally, when GvpG was overexpressed, gas vesicles were still produced, but the cells exhibited a growth defect. Further analysis showed that induction of GvpG arrested cell growth and caused a drop in viable count, suggesting a possible physiological role for this protein linking gas vesicle biogenesis and binary fission. These combined results demonstrate that the stoichiometry of individual gas vesicle proteins is crucially important for controlled organelle morphogenesis and flotation and provides evidence for the first link between gas vesicle assembly and cell division, to our knowledge.

  4. Optical Path Length Calibration: A Standard Approach for Use in Absorption Cell-Based IR-Spectrometric Gas Analysis

    Directory of Open Access Journals (Sweden)

    Javis Anyangwe Nwaboh

    2014-01-01

    Full Text Available We employed a comparison method to determine the optical path length of gas cells which can be used in spectroscopic setup based on laser absorption spectroscopy or FTIR. The method is based on absorption spectroscopy itself. A reference gas cell, whose length is a priori known and desirably traceable to the international system of units (SI, and a gas mixture are used to calibrate the path length of a cell under test. By comparing spectra derived from pressure-dependent measurements on the two cells, the path length of the gas cell under test is determined. The method relies neither on the knowledge of the gas concentration nor on the line strength parameter of the probed transition which is very rarely traceable to the SI and of which the uncertainty is often relatively large. The method is flexible such that any infrared light source and infrared active molecule with isolated lines can be used. We elaborate on the method, substantiate the method by reporting results of this calibration procedure applied to multipass and single pass gas cells of lengths from 0.38 m to 21 m, and compare this to other methods. The relative combined uncertainty of the path length results determined using the comparison method was found to be in the ±0.4% range.

  5. Pre-reforming of natural gas in solid oxide fuel-cell systems

    Energy Technology Data Exchange (ETDEWEB)

    Peters, R.; Riensche, E.; Cremer, P. [Institute for Materials and Processes Systems IWV 3: Energy Process Engineering, Forschungszentrum Juelich (Germany)

    2000-03-01

    Several measures concerning fuel processing in a solid oxide fuel cell (SOFC) system offer the possibility of significant cost reduction and higher system efficiencies. For SOFC systems, the ratio between internal and pre-reforming has to be optimized on the basis of experimental performance data. Furthermore, anode gas recycling by an injector in front of the pre-reformer can eliminate the steam generator and the corresponding heat of evaporation. A detailed study is carried out on pre-reforming in a reformer of considerable size (10 kW{sub el}). Simulating anode gas recycling with an injector, the influence of carbon dioxide on reactor performance was studied. Also, the dependence of the methanol conversion on mass flow and temperature will be discussed. In addition, some results concerning the dynamic behaviour of the pre-reformer are given. (orig.)

  6. Design optimisation of a hybrid solid oxide fuel cell and gas turbine power generation system

    Energy Technology Data Exchange (ETDEWEB)

    Williams, G.J.; Siddle, A.; Pointon, K.

    2001-07-01

    The objectives of the combined ALSTOM Power Technology and Advantica Technologies project are reported as: (a) to design a gas turbine (GT) unit compatible with a solid oxide fuel cell (SOFC) in a high efficiency power system and aimed at the Distributed Power application range of 1-20MW, and (b) to identify the main features and components of a 'Proof of Concept' hybrid unit of output around 0.1MW, based on existing or near-market technology. The study showed: (i) while the potential for high efficiency SOFC + GT hybrid cycles is clear, little effort has been put into the design of the gas turbine and some other components and (ii) there is room for commercial exploitation in the areas of both component manufacture and system supply.

  7. A natural-gas fuel processor for a residential fuel cell system

    Science.gov (United States)

    Adachi, H.; Ahmed, S.; Lee, S. H. D.; Papadias, D.; Ahluwalia, R. K.; Bendert, J. C.; Kanner, S. A.; Yamazaki, Y.

    A system model was used to develop an autothermal reforming fuel processor to meet the targets of 80% efficiency (higher heating value) and start-up energy consumption of less than 500 kJ when operated as part of a 1-kWe natural-gas fueled fuel cell system for cogeneration of heat and power. The key catalytic reactors of the fuel processor - namely the autothermal reformer, a two-stage water gas shift reactor and a preferential oxidation reactor - were configured and tested in a breadboard apparatus. Experimental results demonstrated a reformate containing ∼48% hydrogen (on a dry basis and with pure methane as fuel) and less than 5 ppm CO. The effects of steam-to-carbon and part load operations were explored.

  8. Significance of Wheat Flour Dough Rheology to Gas Cell Structure Development in Bread and Other Baked Products

    Science.gov (United States)

    Engmann, Jan

    2008-07-01

    We discuss which rheological material functions of wheat flour dough are most relevant for structure development in baked products under common processing conditions. We consider the growth of gas cells during dough proofing (driven by yeast) and during baking, where the growth is driven by a combination of CO2 desorption, water and ethanol evaporation, and thermal expansion of gas. Attention is given to upper limits on biaxial extension rate and stress and the consequences for the required rheological material functions. The applicability of the "Considère criterion" to predict the probability of coalescence between gas cells and its effect on loaf aeration is briefly discussed.

  9. [Efficiency of oxidant gas generator cells powered by electric or solar energy].

    Science.gov (United States)

    Brust Carmona, H; Benitez, A; Zarco, J; Sánchez, E; Mascher, I

    1998-02-01

    Diseases caused by microbial contaminants in drinking water continue to be a serious problem in countries like Mexico. Chlorination, using chlorine gas or chlorine compounds, is one of the best ways to treat drinking water. However, difficulties in handling chlorine gas and the inefficiency of hypochlorite solution dosing systems--due to sociopolitical, economic, and cultural factors--have reduced the utility of these chlorination procedures, especially in far-flung and inaccessible rural communities. These problems led to the development of appropriate technologies for the disinfection of water by means of the on-site generation of mixed oxidant gases (chlorine and ozone). This system, called MOGGOD, operates through the electrolysis of a common salt solution. Simulated system evaluation using a hydraulic model allowed partial and total costs to be calculated. When powered by electrical energy from the community power grid, the system had an efficiency of 90%, and in 10 hours it was able to generate enough gases to disinfect about 200 m3 of water at a cost of approximately N$8 (US $1.30). When the electrolytic cell was run on energy supplied through a photoelectric cell, the investment costs were higher. A system fed by photovoltaic cells could be justified in isolated communities that lack electricity but have a gravity-fed water distribution system.

  10. Note: Real-time monitoring via second-harmonic interferometry of a flow gas cell for laser wakefield acceleration

    Science.gov (United States)

    Brandi, F.; Giammanco, F.; Conti, F.; Sylla, F.; Lambert, G.; Gizzi, L. A.

    2016-08-01

    The use of a gas cell as a target for laser wakefield acceleration (LWFA) offers the possibility to obtain stable and manageable laser-plasma interaction process, a mandatory condition for practical applications of this emerging technique, especially in multi-stage accelerators. In order to obtain full control of the gas particle number density in the interaction region, thus allowing for a long term stable and manageable LWFA, real-time monitoring is necessary. In fact, the ideal gas law cannot be used to estimate the particle density inside the flow cell based on the preset backing pressure and the room temperature because the gas flow depends on several factors like tubing, regulators, and valves in the gas supply system, as well as vacuum chamber volume and vacuum pump speed/throughput. Here, second-harmonic interferometry is applied to measure the particle number density inside a flow gas cell designed for LWFA. The results demonstrate that real-time monitoring is achieved and that using low backing pressure gas (<1 bar) and different cell orifice diameters (<2 mm) it is possible to finely tune the number density up to the 1019 cm-3 range well suited for LWFA.

  11. Note: Real-time monitoring via second-harmonic interferometry of a flow gas cell for laser wakefield acceleration.

    Science.gov (United States)

    Brandi, F; Giammanco, F; Conti, F; Sylla, F; Lambert, G; Gizzi, L A

    2016-08-01

    The use of a gas cell as a target for laser wakefield acceleration (LWFA) offers the possibility to obtain stable and manageable laser-plasma interaction process, a mandatory condition for practical applications of this emerging technique, especially in multi-stage accelerators. In order to obtain full control of the gas particle number density in the interaction region, thus allowing for a long term stable and manageable LWFA, real-time monitoring is necessary. In fact, the ideal gas law cannot be used to estimate the particle density inside the flow cell based on the preset backing pressure and the room temperature because the gas flow depends on several factors like tubing, regulators, and valves in the gas supply system, as well as vacuum chamber volume and vacuum pump speed/throughput. Here, second-harmonic interferometry is applied to measure the particle number density inside a flow gas cell designed for LWFA. The results demonstrate that real-time monitoring is achieved and that using low backing pressure gas (<1 bar) and different cell orifice diameters (<2 mm) it is possible to finely tune the number density up to the 10(19) cm(-3) range well suited for LWFA.

  12. Note: Real-time monitoring via second-harmonic interferometry of a flow gas cell for laser wakefield acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Brandi, F., E-mail: fernando.brandi@ino.it [Intense Laser Irradiation Laboratory (ILIL), Istituto Nazionale di Ottica (INO-CNR), Via Moruzzi 1, 56124 Pisa (Italy); Istituto Italiano di Tecnologia (IIT), Via Morego 30, 16163 Genova (Italy); Giammanco, F.; Conti, F. [Dipartimento di Fisica, Università degli Studi di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Plasma Diagnostics and Technologies Ltd., via Matteucci n.38/D, 56124 Pisa (Italy); Sylla, F. [SourceLAB SAS, 86 Rue de Paris, 91400 Orsay (France); Lambert, G. [LOA, ENSTA ParisTech, CNRS, Ecole Polytechnique, Université Paris-Saclay, 828 bd des Maréchaux, 91762 Palaiseau Cedex (France); Gizzi, L. A. [Intense Laser Irradiation Laboratory (ILIL), Istituto Nazionale di Ottica (INO-CNR), Via Moruzzi 1, 56124 Pisa (Italy)

    2016-08-15

    The use of a gas cell as a target for laser wakefield acceleration (LWFA) offers the possibility to obtain stable and manageable laser-plasma interaction process, a mandatory condition for practical applications of this emerging technique, especially in multi-stage accelerators. In order to obtain full control of the gas particle number density in the interaction region, thus allowing for a long term stable and manageable LWFA, real-time monitoring is necessary. In fact, the ideal gas law cannot be used to estimate the particle density inside the flow cell based on the preset backing pressure and the room temperature because the gas flow depends on several factors like tubing, regulators, and valves in the gas supply system, as well as vacuum chamber volume and vacuum pump speed/throughput. Here, second-harmonic interferometry is applied to measure the particle number density inside a flow gas cell designed for LWFA. The results demonstrate that real-time monitoring is achieved and that using low backing pressure gas (<1 bar) and different cell orifice diameters (<2 mm) it is possible to finely tune the number density up to the 10{sup 19} cm{sup −3} range well suited for LWFA.

  13. Thermodynamic Modeling and Dispatch of Distributed Energy Technologies including Fuel Cell -- Gas Turbine Hybrids

    Science.gov (United States)

    McLarty, Dustin Fogle

    Distributed energy systems are a promising means by which to reduce both emissions and costs. Continuous generators must be responsive and highly efficiency to support building dynamics and intermittent on-site renewable power. Fuel cell -- gas turbine hybrids (FC/GT) are fuel-flexible generators capable of ultra-high efficiency, ultra-low emissions, and rapid power response. This work undertakes a detailed study of the electrochemistry, chemistry and mechanical dynamics governing the complex interaction between the individual systems in such a highly coupled hybrid arrangement. The mechanisms leading to the compressor stall/surge phenomena are studied for the increased risk posed to particular hybrid configurations. A novel fuel cell modeling method introduced captures various spatial resolutions, flow geometries, stack configurations and novel heat transfer pathways. Several promising hybrid configurations are analyzed throughout the work and a sensitivity analysis of seven design parameters is conducted. A simple estimating method is introduced for the combined system efficiency of a fuel cell and a turbine using component performance specifications. Existing solid oxide fuel cell technology is capable of hybrid efficiencies greater than 75% (LHV) operating on natural gas, and existing molten carbonate systems greater than 70% (LHV). A dynamic model is calibrated to accurately capture the physical coupling of a FC/GT demonstrator tested at UC Irvine. The 2900 hour experiment highlighted the sensitivity to small perturbations and a need for additional control development. Further sensitivity studies outlined the responsiveness and limits of different control approaches. The capability for substantial turn-down and load following through speed control and flow bypass with minimal impact on internal fuel cell thermal distribution is particularly promising to meet local demands or provide dispatchable support for renewable power. Advanced control and dispatch

  14. Integration of a municipal solid waste gasification plant with solid oxide fuel cell and gas turbine

    DEFF Research Database (Denmark)

    Bellomare, Filippo; Rokni, Masoud

    2013-01-01

    An interesting source of producing energy with low pollutants emission and reduced environmental impact are the biomasses; particularly using Municipal Solid Waste (MSW) as fuel, can be a competitive solution not only to produce energy with negligible costs but also to decrease the storage...... in landfills. A Municipal Solid Waste Gasification Plant Integrated with Solid Oxide Fuel Cell (SOFC) and Gas Turbine (GT) has been studied and the plant is called IGSG (Integrated Gasification SOFC and GT). Gasification plant is fed by MSW to produce syngas by which the anode side of an SOFC is fed wherein...

  15. Focusing of megaampere electron beam in gas cell for production of flash X-ray source

    Energy Technology Data Exchange (ETDEWEB)

    Zinchenko, Vl; Chlenov, A M; Shiyan, V D [Research Institute of Scientific Instruments, Turaevo-Lytkarino (Russian Federation)

    1997-12-31

    One of important problems to be solved in the development of an intense source of flash X-rays is the choice of the optimum design of the high-current diode at the exit of the electron accelerator. The results of numerical investigations of megaampere relativistic electron beam (REB) generation and focusing in a compound diode are discussed. The diode consists of a vacuum field-emission annular cathode, a planar anode, and a gas cell inserted between the anode foil and the target. (author). 2 figs., 5 refs.

  16. Performance of a parallel plate volume cell prototype for a fast iron/gas calorimeter

    Energy Technology Data Exchange (ETDEWEB)

    Bizzeti, A.; Civinini, C.; D' Alessandro, R.; Ferrando, A.; Malinin, A.; Martinez-Laso, L.; Pojidaev, V.

    1993-07-01

    We present the first test of the application of the parallel plate chamber principles for the design of a very fast and radiation-hard iron/gas sampling calorimeter, suitable for very forward regions in detectors for LHC, based on the use of thick iron plates as electrodes. We have built a one cell prototype consisting of three parallel thick iron plates (17 mm each). Results on efficiencies and mean collected charge for minimum ionizing particles with different gases are presented. (Author) 7 refs.

  17. Performance of a parallel plate volume cell prototype for a fast iron/gas calorimeter

    International Nuclear Information System (INIS)

    Bizzeti, A.; Civinini, C.; D'Alessandro, R.; Ferrando, A.; Malinin, A.; Martinez-Laso, L.; Pojidaev, V.

    1993-01-01

    We present the first test of the application of the parallel plate chamber principles for the design of a very fast and radiation-hard iron/gas sampling calorimeter, suitable for very forward regions in detectors for LHC, based on the use of thick iron plates as electrodes. We have built a one cell prototype consisting of three parallel thick iron plates (17 mm each). Results on efficiencies and mean collected charge for minimum ionizing particles with different gases are presented. (Author) 7 refs

  18. Development of an on-line low gas pressure cell for laser ablation-ICP-mass spectrometry

    International Nuclear Information System (INIS)

    Hirata, Takafumi

    2007-01-01

    An on-line low gas pressure cell device has been developed for elemental analysis using laser ablation-ICP-mass spectrometry (LA-ICPMS). Ambient gas in the sample cell was evacuated by a constant-flow diaphragm pump, and the pressure of the sample cell was controlled by changing the flow rate of He-inlet gas. The degree of sample re-deposition around the ablation pit could be reduced when the pressure of the ambient gas was lower than 50 kPa. Produced sample aerosol was drawn and taken from the outlet of the diaphragm pump, and directly introduced into the ICP ion source. The flow rate of He gas controls not only the gas pressure in the sample cell, but also the transport efficiency of the sample particles from the cell to the ICP, and the gas flow rate must be optimized to maximize the signal intensity of the analytes. The flow rates of the He carrier and Ar makeup gas were tuned to maximize the signal intensity of the analytes, and in the case of 238 U from the NIST SRM610 glass material, the signal intensity could be maximized with gas flow rates of 0.4 L/min for He and 1.2 L/min for Ar. The resulting gas pressure in the cell was 30-35 kPa. Using the low gas pressure cell device, the stability in the signal intensities and the resulting precision in isotopic ratio measurements were evaluated. The signal intensity profile of 63 Cu obtained by laser ablation from a metallic sample (NIST SRM976) demonstrated that typical spikes in the transient signal, which can become a large source of analytical error, were no longer found. The resulting precision in the 65 Cu/ 63 Cu ratio measurements was 2-3% (n=10, 2SD), which was half on the level obtained by laser ablation under atmospheric pressure (6-10%). The newly developed low-pressure cell device provides easier optimization of the operational conditions, together with smaller degrees of sample re-deposition and better stability in the signal intensity, even from a metallic sample. (author)

  19. Transformation of a beta gamma hot-cell under air in a tight hot-cell under inert gas

    International Nuclear Information System (INIS)

    Lambert, G.

    1981-05-01

    For several years now, fuel elements from graphite gas reactors have been stored in pools at the Cadarache Center after having been subjected (in general) to laboratory examinations. The CEA has adopted the following re-transfer procedure for these fuel elements while awaiting reprocessing: the fuel elements are extracted from their existing cartridges and transferred into new welded stainless steel containers capable of assuring long term storage. The storage, however, envisaged is temporary and is realized in the Pegase pool, specially adapted for this purpose. This re-transfer operation is envisaged for some 2.300 containers. All the appropriate safety measures will be taken. The various different fuel materials handled are often highly irradiated. The presence of water in certain containers due to loss of leaktightness has led to a series of chemical reactions (corrosion of uranium by water, reactions with magnesium, formation of hydrides). As a result, existing envelopes can contain UO 2 , UH 3 and hydrogen; operations must therefore being carried out in an inert atmosphere (preferably argon). The re-transfer process can not therefore be carried out in a conventional cell. It is therefore envisaged to carry out this work in a leaktight cell in an inert atmosphere. A laboratory cell could be modified to perform these functions. This cell would be reconverted to its original state when operations terminate (in about 3 years time) [fr

  20. Relaxation rates of low-field gas-phase ^129Xe storage cells

    Science.gov (United States)

    Limes, Mark; Saam, Brian

    2010-10-01

    A study of longitudinal nuclear relaxation rates T1 of ^129Xe and Xe-N2 mixtures in a magnetic field of 3.8 mT is presented. In this regime, intrinsic spin relaxation is dominated by the intramolecular spin-rotation interaction due to persistent xenon dimers, a mechanism that can be quelled by introducing large amounts of N2 into the storage cell. Extrinsic spin relaxation is dominated by the wall-relaxation rate, which is the primary quantity of interest for the various low-field storage cells and coatings that we have tested. Previous group work has shown that extremely long gas-phase relaxation times T1 can be obtained, but only at large magnetic fields and low xenon densities. The current work is motivated by the practical benefits of retaining hyperpolarized ^129Xe for extended periods of time in a small magnetic field.

  1. Influence of aging on the heat and gas emissions from commercial lithium ion cells in case of thermal failure

    Directory of Open Access Journals (Sweden)

    Michael Lammer

    2018-03-01

    Full Text Available A method for thermal ramp experiments on cylindrical 18650 Li-ion cells has been established. The method was applied on pristine cells as well as on devices aged by cyclisation or by storage at elevated temperature respectively. The tested cells comprise three types of LiNi0.8Co0.15Al0.05O2 cells for either high power or high energy applications. The heat flux to and from the cell was investigated. Degradation and exothermic breakdown released large amounts of heat and gas. The total gas and heat emission from cycled cells was significantly larger than emission from cells aged by storage. After aging, the low energy cell ICR18650HE4 did not transgress into thermal runaway. Gas composition changed mainly in the early stage of the experiment. The composition of the initial gas release changed from predominantly CO2 towards hydrocarbons. The thermal runaway emitted for all tests a comparable mixture of H2, CO and CO2.

  2. Enhanced nitrogen removal in single-chamber microbial fuel cells with increased gas diffusion areas

    KAUST Repository

    Yan, Hengjing

    2012-11-23

    Single-chamber microbial fuel cells (MFCs) with nitrifiers pre-enriched at the air cathodes have previously been demonstrated as a passive strategy for integrating nitrogen removal into current-generating bioelectrochemical systems. To further define system design parameters for this strategy, we investigated in this study the effects of oxygen diffusion area and COD/N ratio in continuous-flow reactors. Doubling the gas diffusion area by adding an additional air cathode or a diffusion cloth significantly increased the ammonia and COD removal rates (by up to 115% and 39%), ammonia removal efficiency (by up to 134%), the cell voltage and cathode potentials, and the power densities (by a factor of approximately 2). When the COD/N ratio was lowered from 13 to 3, we found up to 244% higher ammonia removal rate but at least 19% lower ammonia removal efficiency. An increase of COD removal rate by up to 27% was also found when the COD/N ratio was lowered from 11 to 3. The Coulombic efficiency was not affected by the additional air cathode, but decreased by an average of 11% with the addition of a diffusion cloth. Ammonia removal by assimilation was also estimated to understand the ammonia removal mechanism in these systems. These results showed that the doubling of gas diffusion area enhanced N and COD removal rates without compromising electrochemical performance. © 2012 Wiley Periodicals, Inc.

  3. Towards radiation detected resonance ionization spectroscopy on transfermium elements in a buffer gas cell

    Energy Technology Data Exchange (ETDEWEB)

    Lautenschlaeger, Felix; Walther, Thomas [Institut fuer Angewandte Physik, TU Darmstadt, 64289 Darmstadt (Germany); Laatiaoui, Mustapha; Block, Michael [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Helmholtz-Institut Mainz, 55128 Mainz (Germany); Lauth, Werner; Backe, Hartmut [Institut fuer Kernphysik, JGU Mainz, 55128 Mainz (Germany); Hessberger, Fritz-Peter [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, 64291 Darmstadt (Germany)

    2013-07-01

    The study of the atomic structure of transfermium elements like nobelium (No) and lawrencium (Lr) via Radiation Detected Resonance Ionization Spectroscopy (RADRIS) is one of the most fascinating disciplines of modern atomic physics. It allows the determination of relativistic effects at the heaviest elements and provides a critical test of theoretical predictions. For these transfermium elements no experimental data on atomic level schemes are available at present. First experiments on {sup 254}No were performed in 2007, in which a buffer gas cell with an overall efficiency of 1%. In this experiment the evaporation temperature of nobelium was determined for the first time. To increase the efficiency of the buffer gas cell, off-line measurements have been performed with nat. ytterbium, the chemical homologue of nobelium. Also on-line experiments during a parasitic beam-time in 2012 provided an insight into the critical parameters of our setup. The results of the off-line and on-line measurements are briefly summarized in this talk.

  4. High glucose contributes to the proliferation and migration of non-small cell lung cancer cells via GAS5-TRIB3 axis.

    Science.gov (United States)

    Ding, Cheng-Zhi; Guo, Xu-Feng; Wang, Guo-Lei; Wang, Hong-Tao; Xu, Guang-Hui; Liu, Yuan-Yuan; Wu, Zhen-Jiang; Chen, Yu-Hang; Wang, Jiao; Wang, Wen-Guang

    2018-01-24

    Despite the growing number of studies exhibited an association of diabetes mellitus (DM) and lung cancer progression, the concrete mechanism of DM aggravating lung cancer has not been elucidated. This study was to investigate whether and how high glucose (HG) contribute to the proliferation and migration of non-small cell lung cancer (NSCLC) cells in vitro. In the present study, we confirmed that HG promoted the proliferation and migration of NSCLC cells, and also induced an anti-apoptosis effect on NSCLC cells. Moreover, HG inhibited the expression of GAS5 in NSCLC cells but elevated the protein level of TRIB3. GAS5 overexpression promoted the degradation of TRIB3 protein by ubiquitination and inhibited the HG induced-proliferation, anti-apoptosis and migration of NSCLC cells. Importantly, TRIB3 overexpression reversed the effects of GAS5 on the HG-treated NSCLC cells. Taken together, down-regulated GAS5 by HG significantly enhanced the proliferation, anti-apoptosis and migration in NSCLC cells through TRIB3, thus promoting the carcinogenesis of NSCLC. ©2018 The Author(s).

  5. Water transport in gas diffusion media for PEM fuel cells. Experimental and numerical investigation

    Energy Technology Data Exchange (ETDEWEB)

    Roth, Joerg

    2010-08-20

    The water flux in partially saturated hydrophobic carbon fibre paper for polymer electrolyte membrane fuel cell applications is investigated and compared with the frequently used constitutive two-phase flow model based on Darcy's law. Further, the first steps towards a math-based material design for gas diffusion media are explored in this thesis. Two self-developed ex-situ experiments to investigate the liquid water transport are introduced. The first is a newly developed buoyancy-based measurement of the pressuresaturation relationship on thin porous material with an accuracy of 0.5 kPa for the pressure and {+-} 5% for the saturation. The second experiment measures the pressure drop in dependence of flow rates down to magnitudes of {mu}L/s across the partially saturated thin porous material. This flow rate is relevant for the fuel cell application. The liquid water transport through Toray 060 carbon fibre paper, impregnated with 7% and 10% PTFE is investigated at wet and dry boundary conditions. The experiments are also accompanied by analytical and numerical free surface modelling with the consideration of the material morphology and liquid-solid interaction. The imbibing and draining cases of an arrangement of six fibres at varying solid-liquid interaction and boundary conditions are studied with 'Surface Evolver'. In order to evaluate the findings of ex-situ and modelling work for applicability to water transport in fuel cell operation, the technique of nuclear magnetic resonance (NMR) imaging is assessed. The focus is on the visualisation of 2D and 3D water distribution in the operating fuel cell. The compatibility of the NMR experiment with fuel cell operation in relation to material selection, operating temperature, and current density is addressed. NMR imaging is employed for different current densities, stoichiometries, and fuel cell arrangements. The fuel cell arrangements differ by the cathode diffusion medium. Plain, hydrophobic, and

  6. Dynamic modelling and characterisation of a solid oxide fuel cell integrated in a gas turbine cycle

    Energy Technology Data Exchange (ETDEWEB)

    Thorud, Bjoern

    2005-07-01

    This thesis focuses on three main areas within the field of SOFC/GT-technology: 1) Development of a dynamic SOFC/GT model. 2) Model calibration and sensitivity study. 3) Assessment of the dynamic properties of a SOFC/GT power plant. The SOFC/GT model developed in this thesis describes a pressurised tubular Siemens Westinghouse-type SOFC, which is integrated in a gas turbine cycle. The process further includes a plate-fin recuperator for stack air preheating, a prereformer, an anode exhaust gas recycling loop for steam/carbon-ratio control, an afterburner and a shell-tube heat exchanger for air preheating. The fuel cell tube, the recuperator and the shell-tube heat exchanger are spatially distributed models. The SOFC model is further thermally integrated with the prereformer. The compressor and turbine models are based on performance maps as a general representation of the characteristics. In addition, a shaft model which incorporates moment of inertia is included to account for gas turbine transients. The SOFC model is calibrated against experimentally obtained data from a single-cell experiment performed on a Siemens Westinghouse tubular SOFC. The agreement between the model and the experimental results is good. The sensitivity study revealed that the degree of prereforming is of great importance with respect to the axial temperature distribution of the fuel cell. Types of malfunctions are discussed prior to the dynamic behaviour study. The dynamic study of the SOFC/GT process is performed by simulating small and large load changes according to three different strategies; 1) Load change at constant mean fuel cell temperature. 2) Load change at constant turbine inlet temperature. 3) Load change at constant shaft speed. Of these three strategies, the constant mean fuel cell temperature strategy appears to be the most rapid load change method. Furthermore, this strategy implies the lowest degree of thermal cycling, the smoothest fuel cell temperature distribution and

  7. Selective catalytic oxidation: a new catalytic approach to the desulfurization of natural gas and liquid petroleum gas for fuel cell reformer applications

    Science.gov (United States)

    Lampert, J.

    In both natural gas and liquid petroleum gas (LPG), sulfur degrades the performance of the catalysts used in fuel reformers and fuel cells. In order to improve system performance, the sulfur must be removed to concentrations of less than 200 ppbv (in many applications to less than 20 ppbv) before the fuel reforming operation. Engelhard Corporation presents a unique approach to the desulfurization of natural gas and LPG. This new method catalytically converts the organic and inorganic sulfur species to sulfur oxides. The sulfur oxides are then adsorbed on a high capacity adsorbent. The sulfur compounds in the fuel are converted to sulfur oxides by combining the fuel with a small amount of air. The mixture is then heated from 250 to 270 °C, and contacted with a monolith supported sulfur tolerant catalyst at atmospheric pressure. When Engelhard Corporation demonstrated this catalytic approach in the laboratory, the result showed sulfur breakthrough to be less than 10 ppbv in the case of natural gas, and less than 150 ppbv for LPG. We used a simulated natural gas and LPG mixture, doped with a 50-170 ppmv sulfur compound containing equal concentrations of COS, ethylmercaptan, dimethylsulfide, methylethylsulfide and tetrahydrothiophene. There is no need for recycled H 2 as in the case for hydrodesulfurization.

  8. The utilization of natural gas in the electricity production through fuel cell; A utilizacao do gas natural na geracao distribuida atraves de celulas combustiveis

    Energy Technology Data Exchange (ETDEWEB)

    Bernardi Junior, Paulo

    2004-07-01

    In function of the necessity of electric energy as input of vital importance for the development of the country, this work aims at to offer plus an energy alternative for Brazil. The exploitation of the natural gas reserves recently discovered can be made through modern methods that give as priority the distributed generation and the low ambient impact. All these aspects can be gotten with the use of fuel cell, working with the remodelled natural gas. Increased to the factor of a low ambient impact in the proper generation, the project suggests that the generating source can be located next the consumer, diminishing still more the problems generated for transmission lines, fuel transport, etc. The fuel cell has received a great attention in the international community and some models, some already in commercial period of training, they have shown excellent possibilities of capsize to be one of the future technologies in the generation of electric energy with low ambient impact. (author)

  9. In-situ study of the gas-phase composition and temperature of an intermediate-temperature solid oxide fuel cell anode surface fed by reformate natural gas

    Science.gov (United States)

    Santoni, F.; Silva Mosqueda, D. M.; Pumiglia, D.; Viceconti, E.; Conti, B.; Boigues Muñoz, C.; Bosio, B.; Ulgiati, S.; McPhail, S. J.

    2017-12-01

    An innovative experimental setup is used for in-depth and in-operando characterization of solid oxide fuel cell anodic processes. This work focuses on the heterogeneous reactions taking place on a 121 cm2 anode-supported cell (ASC) running with a H2, CH4, CO2, CO and steam gas mixture as a fuel, using an operating temperature of 923 K. The results have been obtained by analyzing the gas composition and temperature profiles along the anode surface in different conditions: open circuit voltage (OCV) and under two different current densities, 165 mA cm-2 and 330 mA cm-2, corresponding to 27% and 54% of fuel utilization, respectively. The gas composition and temperature analysis results are consistent, allowing to monitor the evolution of the principal chemical and electrochemical reactions along the anode surface. A possible competition between CO2 and H2O in methane internal reforming is shown under OCV condition and low current density values, leading to two different types of methane reforming: Steam Reforming and Dry Reforming. Under a current load of 40 A, the dominance of exothermic reactions leads to a more marked increase of temperature in the portion of the cell close to the inlet revealing that current density is not uniform along the anode surface.

  10. Realizing the dream: greenhouse gas free transportation through the application of Canada's fuel cell technology

    International Nuclear Information System (INIS)

    Adams, W.

    2001-01-01

    Fuel cells (FCs) generate electrical power without combustion using electrochemical processes and therefore do not have to first convert the fuel to heat and shaft-power before electricity is produced. They are, therefore, high efficiency energy converters and unlike batteries are able to continuously provide electrical power as long as fuel and air are fed to the electrodes. Fuel cells are now of great interest to the automotive industry throughout the world. The most economic fuel for fuel cells is reformed natural gas that is favoured by the utility industry, but methanol (as well, ethanol is being proposed by a GM, Shell, Argonne study) is one contender for fuel cells being developed for transportation. Several different fuel cell technologies exist. Recent developments in solid oxide fuel cell (SOFC) technology suggest that SOFCs could more easily adapt to conventional gasoline and diesel fuels and are less prone to catalyst poisoning than other fuel cells such as the solid polymer electrolyte (PEM) type, often also called the proton exchange membrane (PEM) fuel cell, being developed by Ballard in Canada. However, there remain significant development problems for SOFC technology related to the high operating temperatures (700 to 1000 deg C). In this paper, the range of fuel cell technologies now being developed will be reviewed since there is a convergence in the use of fuel cells for the production of power in distributed fixed systems and power sources for transportation. The factors that will determine the dominating technologies for automobile and truck propulsion in the future are the same as those currently in play. These factors are: performance, cost and convenience of the technologies. A common feature in these three factors is efficiency from which the environmental impact of the technology is largely determined-Electric propulsion in some form will ultimately be favoured over combustion systems because combustion systems are limited by fundamental

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

    Science.gov (United States)

    Bitensky, M.W.; Yoshida, Tatsuro

    1997-04-29

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

  12. cGAS Senses Human Cytomegalovirus and Induces Type I Interferon Responses in Human Monocyte-Derived Cells.

    Directory of Open Access Journals (Sweden)

    Jennifer Paijo

    2016-04-01

    Full Text Available Human cytomegalovirus (HCMV infections of healthy individuals are mostly unnoticed and result in viral latency. However, HCMV can also cause devastating disease, e.g., upon reactivation in immunocompromised patients. Yet, little is known about human immune cell sensing of DNA-encoded HCMV. Recent studies indicated that during viral infection the cyclic GMP/AMP synthase (cGAS senses cytosolic DNA and catalyzes formation of the cyclic di-nucleotide cGAMP, which triggers stimulator of interferon genes (STING and thus induces antiviral type I interferon (IFN-I responses. We found that plasmacytoid dendritic cells (pDC as well as monocyte-derived DC and macrophages constitutively expressed cGAS and STING. HCMV infection further induced cGAS, whereas STING expression was only moderately affected. Although pDC expressed particularly high levels of cGAS, and the cGAS/STING axis was functional down-stream of STING, as indicated by IFN-I induction upon synthetic cGAMP treatment, pDC were not susceptible to HCMV infection and mounted IFN-I responses in a TLR9-dependent manner. Conversely, HCMV infected monocyte-derived cells synthesized abundant cGAMP levels that preceded IFN-I production and that correlated with the extent of infection. CRISPR/Cas9- or siRNA-mediated cGAS ablation in monocytic THP-1 cells and primary monocyte-derived cells, respectively, impeded induction of IFN-I responses following HCMV infection. Thus, cGAS is a key sensor of HCMV for IFN-I induction in primary human monocyte-derived DC and macrophages.

  13. LncRNA GAS5 Represses Osteosarcoma Cells Growth and Metastasis via Sponging MiR-203a

    Directory of Open Access Journals (Sweden)

    Yang Wang

    2018-01-01

    Full Text Available Background/Aims: LncRNA GAS5, a growth suppressor, has been reported to exert anti-tumor actions in various cancers, whereas the exact mechanism underling the anti-tumor action is still unclear. This study was aimed to investigate the effect of lncRNA GAS5 on osteosarcoma and tried to decode the underling mechanisms. Methods: Expressions of lncRNA GAS5 in MG-63 cells were silenced by shRNA transfection, while were overexpressed by vector transfection. Cell viability, migration, invasion and apoptosis were respectively assessed by MTT, Transwell assay and flow cytometry. Regulations between lncRNA GAS5 and miR-203a, as well as between miR-203a and TIMP2 were detected by qPCR, western blot and dual luciferase activity assay. Results: LncRNA GAS5 was down-regulated in MG-63 and OS-732 cells compared to hFOB1.19 cells. Silence of lncRNA GAS5 significantly promoted MG-63 cells viability, migration and invasion, and up-regulated Cyclin D1, Cyclin B1, CDK1 and CDK4 expressions. miR-203a was negatively regulated by lncRNA GAS5. The promoting activities of lncRNA GAS5 silence on MG-63 cells growth and metastasis were reversed by miR-203a suppression. TIMP2 was a target of miR-203a and the anti-growth and anti-metastasis actions of miR-203a suppression were reversed by TIMP2 silence. Further, lncRNA GAS5 silence, miR-203a overexpression, and TIMP2 silence could activate PI3K/AKT/GSK3β signaling while block NF-κB signaling. Conclusion: LncRNA GAS5 might be a tumor suppressor in osteosarcoma via sponging miR-203a, sequestering miR-203a away from TIMP2.

  14. Native and enzymatically modified wheat (Triticum aestivum L.) endogenous lipids in bread making: a focus on gas cell stabilization mechanisms.

    Science.gov (United States)

    Gerits, Lien R; Pareyt, Bram; Masure, Hanne G; Delcour, Jan A

    2015-04-01

    Lipopan F and Lecitase Ultra lipases were used in straight dough bread making to study how wheat lipids affect bread loaf volume (LV) and crumb structure setting. Lipase effects on LV were dose and dough piece weight dependent. The bread quality improving mechanisms exerted by endogenous lipids were studied in terms of gluten network strengthening, which indirectly stabilizes gas cells, and in terms of direct interfacial gas cell stabilization. Unlike diacetyl tartaric esters of mono- and diacylglycerols (DATEM, used as control), lipase use did not impact dough extensibility. The effect on dough extensibility was therefore related to its lipid composition at the start of mixing. Both lipases and DATEM strongly increase the levels of polar lipids in dough liquor and their availability for and potential accumulation at gas cell interfaces. Lipases form lysolipids that emulsify other lipids. We speculate that DATEM competes with (endogenous) polar lipids for interacting with gluten proteins. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Feasibly study of gas-cooled test cell for material testing in IFMIF

    International Nuclear Information System (INIS)

    Yonemoto, Yukihiro; Maki, Eiji; Ebara, Shinji; Yokomine, Takehiko; Shimizu, Akihiko; Korenaga, Tadashi

    2002-01-01

    Temperature control performance of test pieces enclosed in IFMIF capsule by using single phase gas was estimated experimentally. The key issue of this study is to obtain the definite value of dimension of test facility and flow conditions of coolant and to clarify the temperature response of test piece to the beam-off scenario. Firstly, we have examined the cooling performance of the test cell originally proposed in IFMIF-KEP and from results of this calculation performed in three dimensional system by using brand-new turbulence model for flow and thermal fields, it is concluded that the drastical change of design of test cell is needed in order to obtain the unformity of temperature of test piece, to improve the responsibility of temperature measurement of test piece, and to relieve the coolant flow condition, especially for inlet pressure value. Thus, we have proposed new design of test cell and test piece arrangement. A mock-up experimental facility was made based on our design and preliminary experiments for temperature control were performed. As a result, we have verified the cooling performance at the case that corresponds to two beam-off scenario by using mock-up facility

  16. Three-dimensional graphene as gas diffusion layer for micro direct methanol fuel cell

    Science.gov (United States)

    Zhu, Yingli; Zhang, Xiaojian; Li, Jianyu; Qi, Gary

    2018-05-01

    The gas diffusion layer (GDL), as an important structure of the membrane electrode assembly (MEA) of the direct methanol fuel cell (DMFC), provides a support layer for the catalyst and the fuel and the product channel. Traditionally, the material of GDL is generally carbon paper (CP). In this paper, a new material, namely three-dimensional graphene (3DG) is used as GDL for micro DMFC. The experimental results reveal that the performance of the DMFC has been improved significantly by application of 3DG. The peak powers increase from 25 mW to 31.2 mW and 32 mW by using 3DG as the anode and cathode GDL instead of CP, respectively. The reason may be the decrease of charge and mass transfer resistance of the cell. This means that the unique 3D porous architecture of the 3DG can provide lower contact resistance and sufficient fuel diffusion paths. The output performance of the cell will be further improved when porous metal current collectors is used.

  17. Development of gas diffusion layer using water based carbon slurry for proton exchange membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Lin, J.F.; Liu, X.; Adame, A.; Villacorta, R. [Fuel Cell Research Laboratory, Engineering Technology Department, Arizona State University, Mesa, AZ 85212 (United States); Wertz, J. [Hollingsworth and Vose Co., A.K. Nicholson Research Lab, 219 Townsend Road, West Groton, MA 01472 (United States); Ahmad, R.; Thommes, M. [Quantachrome Instruments, 1900 Corporate Drive, Boynton Beach, FL 33426 (United States); Kannan, A.M., E-mail: amk@asu.ed [Fuel Cell Research Laboratory, Engineering Technology Department, Arizona State University, Mesa, AZ 85212 (United States)

    2011-01-01

    The micro-porous layer of gas diffusion layers (GDLs) was fabricated with the carbon slurry dispersed in water containing sodium dodecyl sulfate (SDS), by wire rod coating process. The aqueous carbon slurry with micelle-encapsulation was highly consistent and stable without losing any homogeneity even after adding polytetrafluoroethylene (PTFE) binder for hundreds of hours. The surface morphology, contact angle and pore size distribution of the GDLs were examined using SEM, Goniometer and Hg Porosimeter, respectively. GDLs fabricated with various SDS concentrations were assembled into MEAs and evaluated in a single cell PEMFC under diverse operating relative humidity (RH) conditions using H{sub 2}/O{sub 2} and H{sub 2}/air as reactants. The peak power density of the single cell using the GDLs with optimum SDS concentration was 1400 and 500 mW cm{sup -2} with H{sub 2}/O{sub 2} and H{sub 2}/air at 90% RH, respectively. GDLs were also fabricated with isopropyl alcohol (IPA) based carbon slurry for fuel cell performance comparison. It was found that the composition of the carbon slurry, specifically SDS concentration played a critical role in controlling the pore diameter as well as the corresponding pore volumes of the GDLs.

  18. A study of gas bubbles in liquid mercury in a vertical Hele-Shaw cell

    Energy Technology Data Exchange (ETDEWEB)

    Klaasen, B.; Blanpain, B. [KU Leuven, Research Group for High Temperature Processes and Industrial Ecology, Department of Metallurgy and Materials Engineering, Leuven (Belgium); Verhaeghe, F. [KU Leuven, Research Group for High Temperature Processes and Industrial Ecology, Department of Metallurgy and Materials Engineering, Leuven (Belgium); Umicore Group Research and Development, Olen (Belgium); Fransaer, J. [KU Leuven, Research Group for Materials with Novel Functionality, Department of Metallurgy and Materials Engineering, Leuven (Belgium)

    2014-01-15

    High-quality observations of mesoscopic gas bubbles in liquid metal are vital for a further development of pyrometallurgical gas injection reactors. However, the opacity of metals enforces the use of indirect imaging techniques with limited temporal or spatial resolution. In addition, accurate interface tracking requires tomography which further complicates the design of a high-temperature experimental setup. In this paper, an alternative approach is suggested that circumvents these two main restrictions. By injecting gas in a thin layer of liquid metal entrapped between two flat and closely spaced plates, bubbles in a Hele-Shaw flow regime are generated. The resulting quasi-2D multiphase flow phenomena can be fully captured from a single point of view and, when using a non-wetted transparent plate material, the bubbles can be observed directly. The feasibility of this approach is demonstrated by observations on buoyancy-driven nitrogen bubbles in liquid mercury in a vertical Hele-Shaw cell. By using a moving high-speed camera to make continuous close up recordings of individual bubbles, the position and geometry of these bubbles are quantified with a high resolution along their entire path. After a thorough evaluation of the experimental accuracy, this information is used for a detailed analysis of the bubble expansion along the path. While the observed bubble growth is mainly caused by the hydrostatic pressure gradient, a careful assessment of the volume variations for smaller bubbles shows that an accurate bubble description should account for significant dynamic pressure variations that seem to be largely regime dependent. (orig.)

  19. A fractal analytical model for the permeabilities of fibrous gas diffusion layer in proton exchange membrane fuel cells

    International Nuclear Information System (INIS)

    Xiao, Boqi; Fan, Jintu; Ding, Feng

    2014-01-01

    The study of water and gas transport through fibrous gas diffusion layer (GDL) is important to the optimization of proton exchange membrane fuel cells (PEMFCs). In this work, analytical models of dimensionless permeability, and water and gas relative permeabilities of fibrous GDL in PEMFCs are derived using fractal theory. In our models, the structure of fibrous GDL is characterized in terms of porosity, tortuosity fractal dimension (D T ), pore area fractal dimensions (d f ), water phase (d f,w ) and gas phase (d f,g ) fractal dimensions. The predicted dimensionless permeability, water and gas relative permeabilities based on the proposed models are in good agreement with experimental data and predictions of numerical simulations reported in the literature. The model reveals that, although water phase and gas phase fractal dimensions strongly depend on porosity, the water and gas relative permeabilities are independent of porosity and are a function of water saturation only. It is also shown that the dimensionless permeability decreases significantly with the increase of tortuosity fractal dimension. On the other hand, there is only a small decrease in the water and gas relative permeabilities when tortuosity fractal dimension increases. One advantage of the proposed analytical model is that it contains no empirical constant, which is normally required in past models

  20. Two-dimensional simulation of gas concentration impedance for a planar solid oxide fuel cell

    International Nuclear Information System (INIS)

    Fadaei, M.; Mohammadi, R.; Ghassemi, M.

    2014-01-01

    Highlights: • The 2D simulation shows another feature in concentration impedance. • The channel gas transport causes a capacitive behavior. • Anode polarization variation has a significant influence on velocity distribution. • The influence of 2D simulation is important for channel height bigger than 2 mm. - Abstract: This paper presents a two-dimensional model for a planar solid oxide fuel cell (SOFC) anode in order to simulate the steady-state performance characteristics as well as the electrochemical impedance spectra. The developed model couples the mass transport with the electrochemical kinetics. The transient conservation equations (momentum and species equations) are solved numerically and the linear kinetic is used for the anode electrochemistry. In order to solve the system of the nonlinear equations, an in-house code based on the finite volume method is developed and utilized. A parametric study is also carried out and the results are discussed. Results show a capacitive semicircle in the Nyquist plot which is identical to the gas concentration impedance. The simulation results are in good agreement with published data

  1. Two dimensional numerical simulation of gas discharges: comparison between particle-in-cell and FCT techniques

    Energy Technology Data Exchange (ETDEWEB)

    Soria-Hoyo, C; Castellanos, A [Departamento de Electronica y Electromagnetismo, Facultad de Fisica, Universidad de Sevilla, Avda. Reina Mercedes s/n, 41012 Sevilla (Spain); Pontiga, F [Departamento de Fisica Aplicada II, EUAT, Universidad de Sevilla, Avda. Reina Mercedes s/n, 41012 Sevilla (Spain)], E-mail: cshoyo@us.es

    2008-10-21

    Two different numerical techniques have been applied to the numerical integration of equations modelling gas discharges: a finite-difference flux corrected transport (FD-FCT) technique and a particle-in-cell (PIC) technique. The PIC technique here implemented has been specifically designed for the simulation of 2D electrical discharges using cylindrical coordinates. The development and propagation of a streamer between two parallel electrodes has been used as a convenient test to compare the performance of both techniques. In particular, the phase velocity of the cathode directed streamer has been used to check the internal consistency of the numerical simulations. The results obtained from the two techniques are in reasonable agreement with each other, and both techniques have proved their ability to follow the high gradients of charge density and electric field present in this type of problems. Moreover, the streamer velocities predicted by the simulation are in accordance with the typical experimental values.

  2. Two dimensional numerical simulation of gas discharges: comparison between particle-in-cell and FCT techniques

    International Nuclear Information System (INIS)

    Soria-Hoyo, C; Castellanos, A; Pontiga, F

    2008-01-01

    Two different numerical techniques have been applied to the numerical integration of equations modelling gas discharges: a finite-difference flux corrected transport (FD-FCT) technique and a particle-in-cell (PIC) technique. The PIC technique here implemented has been specifically designed for the simulation of 2D electrical discharges using cylindrical coordinates. The development and propagation of a streamer between two parallel electrodes has been used as a convenient test to compare the performance of both techniques. In particular, the phase velocity of the cathode directed streamer has been used to check the internal consistency of the numerical simulations. The results obtained from the two techniques are in reasonable agreement with each other, and both techniques have proved their ability to follow the high gradients of charge density and electric field present in this type of problems. Moreover, the streamer velocities predicted by the simulation are in accordance with the typical experimental values.

  3. Repowering of an Existing Power Plant by Means of Gas Turbine and Solid Oxide Fuel Cell

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2014-01-01

    Repowering is a process consisting in a transformation of an old power plant in order to have a greater nameplate capacity or more efficiency, which result in a net increase of power generated. As a consequence of the higher efficiency, the repow ered plant is characterized by higher power output...... and less specific CO2 emissions. Usually, a repowering is performed adding one or more gas turbines to an existing steam cycle which was built decades ago. Thus, traditional repowering results in combine d cycles (CC). High temperature fuel cells (such as SOFC) could also be used as a topping cycle......, reaching global plant efficiency even higher and specific CO2 emissions even lower. Decreasing the operating temperature in a SOFC allows the use of less compl ex materials and construction methods, consequently reducing plant and the electricity cost. A lower working temperature makes it also suitable...

  4. The performance of a thermophilic microbial fuel cell fed with synthesis gas.

    Science.gov (United States)

    Hussain, A; Mehta, P; Raghavan, V; Wang, H; Guiot, S R; Tartakovsky, B

    2012-08-10

    This study demonstrated electricity generation in a thermophilic microbial fuel cell (MFC) operated on synthesis gas (syngas) as the sole electron donor. At 50°C, a volumetric power output of 30-35 mWL(R)(-1) and a syngas conversion efficiency of 87-98% was achieved. The observed pathway of syngas conversion to electricity primarily consisted of a two-step process, where the carbon monoxide and hydrogen were first converted to acetate, which was then consumed by the anodophilic bacteria to produce electricity. A denaturing gradient gel electrophoresis (DGGE) analysis of the 16S rDNA revealed the presence of Geobacter species, Acetobacter, methanogens and several uncultured bacteria and archaea in the anodic chamber. Crown Copyright © 2012. Published by Elsevier Inc. All rights reserved.

  5. Particle-in-cell modeling of streamer branching in CO2 gas

    KAUST Repository

    Levko, Dmitry

    2017-07-07

    The mechanism of streamer branching remains one of the unsolved problems of low-temperature plasma physics. The understanding of this phenomenon requires very high-fidelity models that include, for instance, the kinetic description of electrons. In this paper, we use a two-dimensional particle-in-cell Monte Carlo collisional model to study the branching of anode-directed streamers propagating through short cathode-anode gap filled with atmospheric-pressure CO2 gas. We observe three key phenomena leading to the streamer branching at the considered conditions: flattening of the streamer head, the decrease of the streamer head thickness, and the generation at the streamer head of electrons having the energy larger than 50 eV. For the conditions of our studies, the non-homogeneous distribution of such energetic electrons at the streamer head is probably the primary mechanism responsible for the streamer branching.

  6. The extraction of "2"2"9Th"3"+ from a buffer-gas stopping cell

    International Nuclear Information System (INIS)

    Wense, L. von der; Seiferle, B.; Laatiaoui, M.; Thirolf, P.G.

    2016-01-01

    In the whole landscape of atomic nuclei, "2"2"9Th is currently the only known nucleus which could allow for the development of a nuclear-based frequency standard, as it possesses an isomeric state of just 7.6 eV energy above the ground state. The 3+ charge state is of special importance in this context, as Th"3"+ allows for a simple laser-cooling scheme. Here we emphasize the direct extraction of triply-charged "2"2"9Th from a buffer-gas stopping cell. This finding will not only simplify any future approach of "2"2"9Th ion cooling, but is also used for thorium-beam purification and in this way provides a powerful tool for the direct identification of the "2"2"9Th isomer to ground state nuclear transition.

  7. The GAS5/miR-222 Axis Regulates Proliferation of Gastric Cancer Cells Through the PTEN/Akt/mTOR Pathway.

    Science.gov (United States)

    Li, Yanhua; Gu, Junjiao; Lu, Hong

    2017-12-01

    Several lines of evidence have indicated that growth arrest-specific transcript 5 (GAS5) functions as a tumor suppressor and is aberrantly expressed in multiple cancers. GAS5 was found to be downregulated in gastric cancer (GC) tissues, and ectopic expression of GAS5 inhibited GC cell proliferation. The present study aimed to explore the underlying mechanisms of GAS5 involved in GC cell proliferation. GAS5 and miR-222 expressions in GC cell lines were estimated by quantitative real-time polymerase chain reaction. The effects of GAS5 and miR-222 on GC cell proliferation were assessed by MTT assay and 5-bromo-2-deoxyuridine (BrdU) incorporation assays. The interaction between GAS5 and miR-222 was confirmed by luciferase reporter assay and RNA immunoprecipitation assay. The protein levels of the phosphatase and tensin homolog (PTEN), phosphorylated protein kinase B (Akt) (p-Akt), Akt, phosphorylated mammalian target of rapamycin (mTOR) (p-mTOR), and mTOR were determined by western blot. GAS5 was downregulated and miR-222 was upregulated in GC cells. GAS5 directly targeted and suppressed miR-222 expression. GAS5 overexpression and miR-222 inhibition suppressed cell proliferation, increased PTEN protein level and decreased p-Akt and p-mTOR protein levels in GC cells while GAS5 knockdown and miR-222 overexpression exhibited the opposite effects. Moreover, mechanistic analyses revealed that GAS5 regulated GC cell proliferation through the PTEN/Akt/mTOR pathway by negatively regulating miR-222. GAS5/miR-222 axis regulated proliferation of GC cells through the PTEN/Akt/mTOR pathway, which facilitated the development of lncRNA-directed therapy against this deadly disease.

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

    Science.gov (United States)

    Bitensky, Mark W.; Yoshida, Tatsuro

    1997-01-01

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

  9. Technological evaluation of fuel cells using natural gas for distributed power generation; Avaliacao tecnologica da utilizacao de gas natural em celulas a combustivel para geracao distribuida de energia

    Energy Technology Data Exchange (ETDEWEB)

    Brandao, Mauricio O. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE). Programa de Engenharia Mecanica; Giannini, Marcio P.; Arouca, Mauricio C. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE). Programa de Planejamento Energetico

    2004-07-01

    The search for sustainable and more rational means of power generation motivates the scientific crew to search for more efficient and cleaner systems. Oil dependence becomes from the kind of development that the humanity had and cannot be dismissed. The question is how to use this source in a more intelligent way. Fuel Cells are electrochemical devices that convert into electric energy the chemical energy from oxi-reduction reactions between a fuel and an oxidant. The current fuel used in a Fuel Cell is hydrogen and oxygen is the oxidant. The great advantage of this device is its efficiency, higher than the one achieved with internal combustion engines. Also Fuel Cells are not limited by Carnot's efficiency. This paper is about the implementation of a distributed generation system using Fuel Cells. Technical aspects are approached together with economical and environmental needs. The already existence of Gas pipelines and the grown production of Natural Gas presented by Brazil turns it into a good market for the implementation of this energy source. The evaluation of this paper shows that is technically possible to use NG in Fuel Cells, mostly in South and Southeast regions, applying the distributed generation of energy concept. The most interesting in a strategic manner is that Brazil already have an indication that it's capable of developing this technology, opening a new market tuning with world's new technological developments. Many research centers develop this technology, not only from the cell composition itself, but also manufacturing techniques. (author)

  10. Reversible solid oxide fuel cell for natural gas/renewable hybrid power generation systems

    Science.gov (United States)

    Luo, Yu; Shi, Yixiang; Zheng, Yi; Cai, Ningsheng

    2017-02-01

    Renewable energy (RE) is expected to be the major part of the future energy. Presently, the intermittence and fluctuation of RE lead to the limitation of its penetration. Reversible solid oxide fuel cell (RSOFC) as the energy storage device can effectively store the renewable energy and build a bidirectional connection with natural gas (NG). In this paper, the energy storage strategy was designed to improve the RE penetration and dynamic operation stability in a distributed system coupling wind generators, internal combustion engine, RSOFC and lithium-ion batteries. By compromising the relative deviation of power supply and demand, RE penetration, system efficiency and capacity requirement, the strategy that no more than 36% of the maximum wind power output is directly supplied to users and the other is stored by the combination of battery and reversible solid oxide fuel cell is optimal for the distributed system. In the case, the RE penetration reached 56.9% and the system efficiency reached 55.2%. The maximum relative deviation of power supply and demand is also lower than 4%, which is significantly superior to that in the wind curtailment case.

  11. Wire rod coating process of gas diffusion layers fabrication for proton exchange membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Kannan, A.M.; Sadananda, S.; Parker, D.; Munukutla, L. [Electronic Systems Department, Arizona State University, 7001 E Williams Field Road, Mesa, AZ 85212 (United States); Wertz, J. [Hollingsworth and Vose Co., A.K. Nicholson Research Lab, 219 Townsend Road West Groton, MA 01472 (United States); Thommes, M. [Quantachrome Instruments, 1900 Corporate Drive, Boynton Beach, FL 33426 (United States)

    2008-03-15

    Gas diffusion layers (GDLs) were fabricated using non-woven carbon paper as a macro-porous layer substrate developed by Hollingsworth and Vose Company. A commercially viable coating process was developed using wire rod for coating micro-porous layer by a single pass. The thickness as well as carbon loading in the micro-porous layer was controlled by selecting appropriate wire thickness of the wire rod. Slurry compositions with solid loading as high as 10 wt.% using nano-chain and nano-fiber type carbons were developed using dispersion agents to provide cohesive and homogenous micro-porous layer without any mud-cracking. The surface morphology, wetting characteristics and pore size distribution of the wire rod coated GDLs were examined using FESEM, Goniometer and Hg porosimetry, respectively. The GDLs were evaluated in single cell PEMFC under various operating conditions (temperature and RH) using hydrogen and air as reactants. It was observed that the wire rod coated micro-porous layer with 10 wt.% nano-fibrous carbon based GDLs showed the highest fuel cell performance at 85 C using H{sub 2} and air at 50% RH, compared to all other compositions. (author)

  12. Study on hydrophobicity degradation of gas diffusion layer in proton exchange membrane fuel cells

    International Nuclear Information System (INIS)

    Yu, Shuchun; Li, Xiaojin; Li, Jin; Liu, Sa; Lu, Wangting; Shao, Zhigang; Yi, Baolian

    2013-01-01

    Highlights: • The hydrophobicity degradation mechanism of GDL was proposed thoroughly. • C-O and C=O groups appeared on the surfaces of GDL after immersion. • The relative content of PTFE in GDL decreased after immersion. • The surfaces and inner structure of GDL destroyed after immersion. - Abstract: As one of the essential components of proton exchange membrane fuel cell (PEMFC), gas diffusion layer (GDL) is of importance on water management, as well on the performance and durability of PEMFC. In this paper, the hydrophobicity degradation of GDL was investigated by immersing it in the 1.0 mol L −1 H 2 SO 4 solution saturated by air for 1200 h. From the measurements of contact angle and water permeability, the hydrophobic characteristics of the pristine and immersed GDLs were compared. To investigate the causes for hydrophobicity degradation, the GDLs were analyzed by scanning electron microscopy, X-ray photoelectron spectroscopy and thermogravimetry. Further, the chemical compositions of H 2 SO 4 solutions before and after immersion test were analyzed with infrared spectroscopy. Results showed that the hydrophobicity of immersed GDL decreased distinctly, which was caused by the damage of physical structure and surface characteristics. Moreover, the immersed GDL showed a worse fuel cell performance than the pristine GDL, especially under a low humidity condition

  13. CT and clinical study for intratumoral gas formation in post transarterial embolization of hepatoma and renal cell carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Katsuragi, M; Matsuo, N; Yoshikawa, K [Nara Medical Univ., Kashihara (Japan)

    1982-09-01

    Thirty-two patients with hepatocellular carcinoma and six patients with renal cell carcinoma for whom the arterial embolization therapy was performed were studied by CT and clinical follow-up for investigating intratumoral gas detected on CT in post-embolization cases. The intratumoral air was found by CT in seven patients with hepatocellular carcinoma and four patients with renal cell carcinoma. The air was composed of a collection of multiple small round gas bubbles in the embolized tumor except in one case where it formed a serpiginous pattern. There was no hematologic nor clinical evidence of liver abscess in all the cases. It was possible to distinguish gas from abscess or fat by a combination of CT and clinical findings.

  14. Pretreated Landfill Gas Conversion Process via a Catalytic Membrane Reactor for Renewable Combined Fuel Cell-Power Generation

    Directory of Open Access Journals (Sweden)

    Zoe Ziaka

    2013-01-01

    Full Text Available A new landfill gas-based reforming catalytic processing system for the conversion of gaseous hydrocarbons, such as incoming methane to hydrogen and carbon oxide mixtures, is described and analyzed. The exit synthesis gas (syn-gas is fed to power effectively high-temperature fuel cells such as SOFC types for combined efficient electricity generation. The current research work is also referred on the description and design aspects of permreactors (permeable reformers carrying the same type of landfill gas-reforming reactions. Membrane reactors is a new technology that can be applied efficiently in such systems. Membrane reactors seem to perform better than the nonmembrane traditional reactors. The aim of this research includes turnkey system and process development for the landfill-based power generation and fuel cell industries. Also, a discussion of the efficient utilization of landfill and waste type resources for combined green-type/renewable power generation with increased processing capacity and efficiency via fuel cell systems is taking place. Moreover, pollution reduction is an additional design consideration in the current catalytic processors fuel cell cycles.

  15. Carbon Nanotube-Silicon Nanowire Heterojunction Solar Cells with Gas-Dependent Photovoltaic Performances and Their Application in Self-Powered NO2 Detecting.

    Science.gov (United States)

    Jia, Yi; Zhang, Zexia; Xiao, Lin; Lv, Ruitao

    2016-12-01

    A multifunctional device combining photovoltaic conversion and toxic gas sensitivity is reported. In this device, carbon nanotube (CNT) membranes are used to cover onto silicon nanowire (SiNW) arrays to form heterojunction. The porous structure and large specific surface area in the heterojunction structure are both benefits for gas adsorption. In virtue of these merits, gas doping is a feasible method to improve cell's performance and the device can also work as a self-powered gas sensor beyond a solar cell. It shows a significant improvement in cell efficiency (more than 200 times) after NO2 molecules doping (device working as a solar cell) and a fast, reversible response property for NO2 detection (device working as a gas sensor). Such multifunctional CNT-SiNW structure can be expected to open a new avenue for developing self-powered, efficient toxic gas-sensing devices in the future.

  16. Study of gas holdup and pressure characteristics in a column flotation cell using coal

    Energy Technology Data Exchange (ETDEWEB)

    Shukla, S.C.; Kundu, G.; Mukherjee, D. [Indian Institute of Technology, Kharagpur (India). Dept. of Chemical Engineering

    2010-07-15

    Present work has been carried out to observe the effect of process variables (gas flow rate, feed flow rate, solid concentration and frother concentration) on gas holdup and pressure characteristics in flotation column using coal. Gas holdup has been estimated using phase separation method while piezometers have been used to obtain column's axial pressure profile. It was observed that gas holdup in collection zone was affected by both air as well as feed flow rates. Up to 6% change in gas holdup may occur when the feed flow rate changes from 1-2 cm/s. It was also observed that addition of coal decreased the gas holdup while addition of methyl isobutyl carbinol (MIBC) had opposite effect. Almost linear variation in columns axial pressure characteristics has been observed with gas flow rate. An empirical relationship between gas holdup in the flotation column with column's axial pressure difference was developed.

  17. Thermodynamic analysis of a combined gas turbine power plant with a solid oxide fuel cell for marine applications

    Directory of Open Access Journals (Sweden)

    Yousri M.A. Welaya

    2013-12-01

    Full Text Available Strong restrictions on emissions from marine power plants (particularly SOx, NOx will probably be adopted in the near future. In this paper, a combined solid oxide fuel cell (SOFC and gas turbine fuelled by natural gas is proposed as an attractive option to limit the environmental impact of the marine sector. It includes a study of a heat-recovery system for 18 MW SOFC fuelled by natural gas, to provide the electric power demand onboard commercial vessels. Feasible heat-recovery systems are investigated, taking into account different operating conditions of the combined system. Two types of SOFC are considered, tubular and planar SOFCs, operated with either natural gas or hydrogen fuels. This paper includes a detailed thermodynamic analysis for the combined system. Mass and energy balances are performed, not only for the whole plant but also for each individual component, in order to evaluate the thermal efficiency of the combined cycle. In addition, the effect of using natural gas as a fuel on the fuel cell voltage and performance is investigated. It is found that a high overall efficiency approaching 70% may be achieved with an optimum configuration using SOFC system under pressure. The hybrid system would also reduce emissions, fuel consumption, and improve the total system efficiency.

  18. Fabrication of gas diffusion layer based on x-y robotic spraying technique for proton exchange membrane fuel cell application

    International Nuclear Information System (INIS)

    Sitanggang, Ramli; Mohamad, Abu Bakar; Daud, Wan Ramli Wan; Kadhum, Abdul Amir H.; Iyuke, S.E.

    2009-01-01

    The x-y robotic spraying technique developed in the Universiti Kebangsaan Malaysia is capable of fabricating various sizes of thickness and porosity of gas diffusion layer (GDL) used in the proton exchange membrane fuel cell (PEMFC). These parameters are obtained by varying the characteristic spray numbers of the robotic spraying machine. This investigation results were adequately represented with mathematical equations for hydrogen gas distribution in GDL. Volumetric modulus (M) parameter is used to determine the value of current density produced on the electrode of a single cell PEMFC. Thus the M parameter can be employed as indicator for a successful GDL fabrication. GDL type 4 has three variables of layer design that can be optimized to function as gas distributor, gas storage, flooding preventer on GDL surface, to evacuate water from the electrode and to control the electrical conductivity. The gas distribution in GDL was mathematically represented with average error of 15.5%. The M value of GDL type 4 according to the model was 0.22 cm 3 /s and yielded a current density of 750 A/m 2 .

  19. Thermodynamic analysis of a combined gas turbine power plant with a solid oxide fuel cell for marine applications

    Science.gov (United States)

    Welaya, Yousri M. A.; Mosleh, M.; Ammar, Nader R.

    2013-12-01

    Strong restrictions on emissions from marine power plants (particularly SOx, NOx) will probably be adopted in the near future. In this paper, a combined solid oxide fuel cell (SOFC) and gas turbine fuelled by natural gas is proposed as an attractive option to limit the environmental impact of the marine sector. It includes a study of a heatrecovery system for 18 MW SOFC fuelled by natural gas, to provide the electric power demand onboard commercial vessels. Feasible heat-recovery systems are investigated, taking into account different operating conditions of the combined system. Two types of SOFC are considered, tubular and planar SOFCs, operated with either natural gas or hydrogen fuels. This paper includes a detailed thermodynamic analysis for the combined system. Mass and energy balances are performed, not only for the whole plant but also for each individual component, in order to evaluate the thermal efficiency of the combined cycle. In addition, the effect of using natural gas as a fuel on the fuel cell voltage and performance is investigated. It is found that a high overall efficiency approaching 70% may be achieved with an optimum configuration using SOFC system under pressure. The hybrid system would also reduce emissions, fuel consumption, and improve the total system efficiency.

  20. Endothelial cell behaviour on gas-plasma-treated PLA surfaces: the roles of surface chemistry and roughness.

    Science.gov (United States)

    Shah, Amita; Shah, Sarita; Mani, Gopinath; Wenke, Joseph; Agrawal, Mauli

    2011-04-01

    Glow-discharge gas-plasma (GP) treatment has been shown to induce surface modifications such that cell adhesion and growth are enhanced. However, it is not known which gas used in GP treatment is optimal for endothelial cell function. Polylactic acid (PLA) films treated oxygen, argon, or nitrogen GP were characterized using contact angles, scanning electron microscopy, atomic force microscopy, optical profilometry, and x-ray photoelectron spectroscopy. All three GP treatments decreased the carbon atomic concentration and surface roughness and increased the oxygen atomic concentration. Human umbilical vein endothelial cells were cultured on the PLA films for up to 7 days. Based on proliferation and live/dead assays, surface chemistry was shown to have the greatest effect on the attachment, proliferation, and viability of these cells, while roughness did not have a significant influence. Of the different gases, endothelial cell viability, attachment and proliferation were most significantly increased on PLA surfaces treated with oxygen and argon gas plasma. Copyright © 2010 John Wiley & Sons, Ltd.

  1. The effects of gas humidification with high-flow nasal cannula on cultured human airway epithelial cells.

    Science.gov (United States)

    Chidekel, Aaron; Zhu, Yan; Wang, Jordan; Mosko, John J; Rodriguez, Elena; Shaffer, Thomas H

    2012-01-01

    Humidification of inspired gas is important for patients receiving respiratory support. High-flow nasal cannula (HFNC) effectively provides temperature and humidity-controlled gas to the airway. We hypothesized that various levels of gas humidification would have differential effects on airway epithelial monolayers. Calu-3 monolayers were placed in environmental chambers at 37°C with relative humidity (RH) 90% (HFNC) for 4 and 8 hours with 10 L/min of room air. At 4 and 8 hours, cell viability and transepithelial resistance measurements were performed, apical surface fluid was collected and assayed for indices of cell inflammation and function, and cells were harvested for histology (n = 6/condition). Transepithelial resistance and cell viability decreased over time (P < 0.001) between HFNC and dry groups (P < 0.001). Total protein secretion increased at 8 hours in the dry group (P < 0.001). Secretion of interleukin (IL)-6 and IL-8 in the dry group was greater than the other groups at 8 hours (P < 0.001). Histological analysis showed increasing injury over time for the dry group. These data demonstrate that exposure to low humidity results in reduced epithelial cell function and increased inflammation.

  2. The Effects of Gas Humidification with High-Flow Nasal Cannula on Cultured Human Airway Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Aaron Chidekel

    2012-01-01

    Full Text Available Humidification of inspired gas is important for patients receiving respiratory support. High-flow nasal cannula (HFNC effectively provides temperature and humidity-controlled gas to the airway. We hypothesized that various levels of gas humidification would have differential effects on airway epithelial monolayers. Calu-3 monolayers were placed in environmental chambers at 37°C with relative humidity (RH 90% (HFNC for 4 and 8 hours with 10 L/min of room air. At 4 and 8 hours, cell viability and transepithelial resistance measurements were performed, apical surface fluid was collected and assayed for indices of cell inflammation and function, and cells were harvested for histology (n=6/condition. Transepithelial resistance and cell viability decreased over time (P<0.001 between HFNC and dry groups (P<0.001. Total protein secretion increased at 8 hours in the dry group (P<0.001. Secretion of interleukin (IL-6 and IL-8 in the dry group was greater than the other groups at 8 hours (P<0.001. Histological analysis showed increasing injury over time for the dry group. These data demonstrate that exposure to low humidity results in reduced epithelial cell function and increased inflammation.

  3. A Study of the Influence of Gas Channel Parameters on HT-PEM Fuel Cell Performance Using FEM Analysis

    Directory of Open Access Journals (Sweden)

    Ionescu Viorel

    2016-01-01

    Full Text Available Proton Exchange Membrane Fuel Cells (PEMFC are highly efficient power generators, achieving up to 50–60% conversion efficiency, even in sizes of a few kilowatts. Comsol Multiphysics, a commercial solver based on the Finite Element Method (FEM was used for developing a three dimensional model of a high temperature PEMFC that can deal with both anode and cathode flow field for examining the micro flow channel with electrochemical reaction. Cathode gas flow velocity influence on the cell performance was investigated at first. Polarization curves for three different channel widths (0.8, 1.6 and 2.4 mm and three different channel depths (1, 2 and 3 mm were computed at a cathode inlet flow velocity of 0.06 m/s. Oxygen molar concentration at cathode catalyst layer-GDL channel interface and local current density variation along the cell length were also studied for specific gas channel geometries.

  4. Gas-to-liquids synthetic fuels for use in fuel cells : reformability, energy density, and infrastructure compatibility.

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, S.; Kopasz, J. P.; Russell, B. J.; Tomlinson, H. L.

    1999-09-08

    The fuel cell has many potential applications, from power sources for electric hybrid vehicles to small power plants for commercial buildings. The choice of fuel will be critical to the pace of its commercialization. This paper reviews the various liquid fuels being considered as an alternative to direct hydrogen gas for the fuel cell application, presents calculations of the hydrogen and carbon dioxide yields from autothermal reforming of candidate liquid fuels, and reports the product gas composition measured from the autothermal reforming of a synthetic fuel in a micro-reactor. The hydrogen yield for a synthetic paraffin fuel produced by a cobalt-based Fischer-Tropsch process was found to be similar to that of retail gasoline. The advantages of the synthetic fuel are that it contains no contaminants that would poison the fuel cell catalyst, is relatively benign to the environment, and could be transported in the existing fuel distribution system.

  5. The design of stationary and mobile solid oxide fuel cell-gas turbine systems

    Science.gov (United States)

    Winkler, Wolfgang; Lorenz, Hagen

    A general thermodynamic model has shown that combined fuel cell cycles may reach an electric-efficiency of more than 80%. This value is one of the targets of the Department of Energy (DOE) solid oxide fuel cell-gas turbine (SOFC-GT) program. The combination of a SOFC and GT connects the air flow of the heat engine and the cell cooling. The principle strategy in order to reach high electrical-efficiencies is to avoid a high excess air for the cell cooling and heat losses. Simple combined SOFC-GT cycles show an efficiency between 60 and 72%. The combination of the SOFC and the GT can be done by using an external cooling or by dividing the stack into multiple sub-stacks with a GT behind each sub-stack as the necessary heat sink. The heat exchangers (HEXs) of a system with an external cooling have the benefit of a pressurization on both sides and therefore, have a high heat exchange coefficient. The pressurization on both sides delivers a low stress to the HEX material. The combination of both principles leads to a reheat (RH)-SOFC-GT cycle that can be improved by a steam turbine (ST) cycle. The first results of a study of such a RH-SOFC-GT-ST cycle indicate that a cycle design with an efficiency of more than 80% is possible and confirm the predictions by the theoretical thermodynamic model mentioned above. The extremely short heat-up time of a thin tubular SOFC and the market entrance of the micro-turbines give the option of using these SOFC-GT designs for mobile applications. The possible use of hydrocarbons such as diesel oil is an important benefit of the SOFC. The micro-turbine and the SOFC stack will be matched depending on the start-up requirements of the mobile system. The minimization of the volume needed is a key issue. The efficiency of small GTs is lower than the efficiency of large GTs due to the influence of the leakage within the stages of GTs increasing with a decreasing size of the GT. Thus, the SOFC module pressure must be lower than in larger

  6. Fabricating method of gas diffusion electrode for fuel cell. Nenryo denchiyo gas kakusan denkyoku no seizo hoho

    Energy Technology Data Exchange (ETDEWEB)

    Harada, H [Yokohama (Japan)

    1994-01-28

    When the cation exchange film of the solid high polymer electrolyte fuel cell which uses the cation exchange film as the electrolyte (PEMFC) is bonded with the electrode catalyst layers for the anode and cathode, the hot-press conditions are severe and satisfactory bonding is hard to be achieved because the softening temperature of polytetrafluoroethylene used as the binder for the bonding is higher than that of the cation exchange film. This invention is concerned with a means of obtaining PEMFC which can generate high cell voltage, wherein perfluorosulfonic acid system copolymer solution or dispersed solution similar to that used for the cation exchange film is used as the binder when bonding carbon cloth or carbon paper coated with electrode catalyst layers for anode and cathode to the cation exchange film, setting of hot-pressing conditions is made easier, and the adhesion and bonding of the cation exchange film surface and the electrode catalyst layers are improved. 1 fig.

  7. Production of "Green Natural Gas" Using Solid Oxide Electrolysis Cells (SOEC): Status of Technology and Costs

    DEFF Research Database (Denmark)

    Mogensen, Mogens Bjerg; Jensen, Søren Højgaard; Ebbesen, Sune Dalgaard

    2012-01-01

    energy sources only. Also dimethyl ether (DME = (CH3)2O), which might be called Liquefied Green Gas, LGG, in analogy to Liquefied Petroleum Gas, LPG, because DME has properties similar to LPG. It further gives a short review of the state of the art of electrolysis in general and SOEC in particular......This paper gives arguments in favour of using green natural gas (GNG) as storage media for the intermittent renewable energy sources. GNG is here defined as being CH4, i.e. methane, often called synthetic natural gas or substitute natural gas (SNG), produced using renewable or at least CO2 neutral....... Production of synthesis gas (H2 + CO) from CO2 and H2O using SOEC technology is evaluated. GNG and LGG can be produced from synthesis gas (or short: syngas) by means of well established commercially available catalysis technology. Finally, estimations of costs and efficiencies are presented and the relative...

  8. An innovative intermittent hypoxia model for cell cultures allowing fast Po2 oscillations with minimal gas consumption.

    Science.gov (United States)

    Minoves, Mélanie; Morand, Jessica; Perriot, Frédéric; Chatard, Morgane; Gonthier, Brigitte; Lemarié, Emeline; Menut, Jean-Baptiste; Polak, Jan; Pépin, Jean-Louis; Godin-Ribuot, Diane; Briançon-Marjollet, Anne

    2017-10-01

    Performing hypoxia-reoxygenation cycles in cell culture with a cycle duration accurately reflecting what occurs in obstructive sleep apnea (OSA) patients is a difficult but crucial technical challenge. Our goal was to develop a novel device to expose multiple cell culture dishes to intermittent hypoxia (IH) cycles relevant to OSA with limited gas consumption. With gas flows as low as 200 ml/min, our combination of plate holders with gas-permeable cultureware generates rapid normoxia-hypoxia cycles. Cycles alternating 1 min at 20% O 2 followed by 1 min at 2% O 2 resulted in Po 2 values ranging from 124 to 44 mmHg. Extending hypoxic and normoxic phases to 10 min allowed Po 2 variations from 120 to 25 mmHg. The volume of culture medium or the presence of cells only modestly affected the Po 2 variations. In contrast, the nadir of the hypoxia phase increased when measured at different heights above the membrane. We validated the physiological relevance of this model by showing that hypoxia inducible factor-1α expression was significantly increased by IH exposure in human aortic endothelial cells, murine breast carcinoma (4T1) cells as well as in a blood-brain barrier model (2.5-, 1.5-, and 6-fold increases, respectively). In conclusion, we have established a new device to perform rapid intermittent hypoxia cycles in cell cultures, with minimal gas consumption and the possibility to expose several culture dishes simultaneously. This device will allow functional studies of the consequences of IH and deciphering of the molecular biology of IH at the cellular level using oxygen cycles that are clinically relevant to OSA. Copyright © 2017 the American Physiological Society.

  9. Simulated coal-gas fueled carbonate fuel cell power plant system verification. Final report, September 1990--June 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-03-01

    This report summarizes work performed under U.S. Department of Energy, Morgantown Energy Technology Center (DOE/METC) Contract DE-AC-90MC27168 for September 1990 through March 1995. Energy Research Corporation (ERC), with support from DOE, EPRI, and utilities, has been developing a carbonate fuel cell technology. ERC`s design is a unique direct fuel cell (DFC) which does not need an external fuel reformer. An alliance was formed with a representative group of utilities and, with their input, a commercial entry product was chosen. The first 2 MW demonstration unit was planned and construction begun at Santa Clara, CA. A conceptual design of a 10OMW-Class dual fuel power plant was developed; economics of natural gas versus coal gas use were analyzed. A facility was set up to manufacture 2 MW/yr of carbonate fuel cell stacks. A 100kW-Class subscale power plant was built and several stacks were tested. This power plant has achieved an efficiency of {approximately}50% (LHV) from pipeline natural gas to direct current electricity conversion. Over 6,000 hours of operation including 5,000 cumulative hours of stack operation were demonstrated. One stack was operated on natural gas at 130 kW, which is the highest carbonate fuel cell power produced to date, at 74% fuel utilization, with excellent performance distribution across the stack. In parallel, carbonate fuel cell performance has been improved, component materials have been proven stable with lifetimes projected to 40,000 hours. Matrix strength, electrolyte distribution, and cell decay rate have been improved. Major progress has been achieved in lowering stack cost.

  10. Fuel composition effect on cathode airflow control in fuel cell gas turbine hybrid systems

    Science.gov (United States)

    Zhou, Nana; Zaccaria, Valentina; Tucker, David

    2018-04-01

    Cathode airflow regulation is considered an effective means for thermal management in solid oxide fuel cell gas turbine (SOFC-GT) hybrid system. However, performance and controllability are observed to vary significantly with different fuel compositions. Because a complete system characterization with any possible fuel composition is not feasible, the need arises for robust controllers. The sufficiency of robust control is dictated by the effective change of operating state given the new composition used. It is possible that controller response could become unstable without a change in the gains from one state to the other. In this paper, cathode airflow transients are analyzed in a SOFC-GT system using syngas as fuel composition, comparing with previous work which used humidified hydrogen. Transfer functions are developed to map the relationship between the airflow bypass and several key variables. The impact of fuel composition on system control is quantified by evaluating the difference between gains and poles in transfer functions. Significant variations in the gains and the poles, more than 20% in most cases, are found in turbine rotational speed and cathode airflow. The results of this work provide a guideline for the development of future control strategies to face fuel composition changes.

  11. Studies of Helium Based Gas Mixtures Using a Small Cell Drift Chamber

    International Nuclear Information System (INIS)

    Heise, Jaret; British Columbia U.

    2006-01-01

    An international collaboration is currently working on the construction and design of an asymmetric B Factory at the Stanford Linear Accelerator Center that will be ready to collect data in 1999. The main physics motivation for such a facility is to test the description and mechanism of CP violation in the Standard Model of particle physics and provide insight into the question of why more matter than antimatter is observed in the universe today. In particular, this experiment will measure CP violation in the decay of B mesons. In the early stages of this effort, the Canadian contingent proposed to build the central tracking chamber for the BABAR detector. Presently, a prototype drift chamber is in operation and studies are being performed to test some of the unique features of drift chamber design dictated by the conditions of the experiment. Using cosmic muons, it is possible to study tracking and pattern recognition in the prototype chamber, and therefore calculate the efficiency and spatial resolution of the prototype chamber cells. These performance features will be used to test whether or not the helium-based gas mixtures proposed for the BABAR drift chamber are a viable alternative to the more traditional argon-based gases

  12. High-quality electromagnetically-induced absorption resonances in a buffer-gas-filled vapour cell

    Science.gov (United States)

    Brazhnikov, D. V.; Ignatovich, S. M.; Vishnyakov, V. I.; Skvortsov, M. N.; Andreeva, Ch; Entin, V. M.; Ryabtsev, I. I.

    2018-02-01

    Magneto-optical subnatural-linewidth resonances of electromagnetically-induced absorption (EIA) in an alkali vapour cell have been experimentally studied. The observation configuration includes using two counter-propagating pumps and probe light waves with mutually orthogonal linear polarizations, exciting an open optical transition in the 87Rb D 1 line in the presence of argon buffer gas. The EIA signals registered in a probe-wave transmission reach an unprecedented contrast of about 135% with respect to the wide ‘Doppler’ absorption pedestal and 29% with respect to the level of background transmission signal. These contrast values correspond to a relatively small resonance full width at half maximum of about 7.2 mG (5.2 kHz). The width of the narrowest EIA resonance observed is about 2.1 mG (1.5 kHz). To our knowledge, such a large relative contrast at the kHz-width is the record result for EIA resonances. In general, the work has experimentally proved that the magneto-optical scheme used has very good prospects for various quantum technologies (quantum sensors of weak magnetic fields, optical switches and other photonic elements).

  13. The presence of hydrogenotrophic methanogens in the inoculum improves methane gas production in microbial electrolysis cells.

    KAUST Repository

    Siegert, Michael; Li, Xiu-Fen; Yates, Matthew D; Logan, Bruce E

    2014-01-01

    High current densities in microbial electrolysis cells (MECs) result from the predominance of various Geobacter species on the anode, but it is not known if archaeal communities similarly converge to one specific genus. MECs were examined here on the basis of maximum methane production and current density relative to the inoculum community structure. We used anaerobic digester (AD) sludge dominated by acetoclastic Methanosaeta, and an anaerobic bog sediment where hydrogenotrophic methanogens were detected. Inoculation using solids to medium ratio of 25% (w/v) resulted in the highest methane production rates (0.27 mL mL(-1) cm(-2), gas volume normalized by liquid volume and cathode projected area) and highest peak current densities (0.5 mA cm(-2)) for the bog sample. Methane production was independent of solid to medium ratio when AD sludge was used as the inoculum. 16S rRNA gene community analysis using pyrosequencing and quantitative PCR confirmed the convergence of Archaea to Methanobacterium and Methanobrevibacter, and of Bacteria to Geobacter, despite their absence in AD sludge. Combined with other studies, these findings suggest that Archaea of the hydrogenotrophic genera Methanobacterium and Methanobrevibacter are the most important microorganisms for methane production in MECs and that their presence in the inoculum improves the performance.

  14. Ultra Efficient CHHP Using a High Temperature Fuel Cell to Provide On-Site Process Reducing Gas, Clean Power, and Heat

    Energy Technology Data Exchange (ETDEWEB)

    Jahnke, Fred C. [Fuelcell Energy, Inc., Danbury, CT (United States)

    2015-06-30

    FuelCell Energy and ACuPowder investigated and demonstrated the use of waste anode exhaust gas from a high temperature fuel cell for replacing the reducing gas in a metal processing furnace. Currently companies purchase high pressure or liquefied gases for the reducing gas which requires substantial energy in production, compression/liquefaction, and transportation, all of which is eliminated by on-site use of anode exhaust gas as reducing gas. We performed research on the impact of the gas composition on product quality and then demonstrated at FuelCell Energy’s manufacturing facility in Torrington, Connecticut. This demonstration project continues to operate even though the research program is completed as it provides substantial benefits to the manufacturing facility by supplying power, heat, and hydrogen.

  15. The hormone response element mimic sequence of GAS5 lncRNA is sufficient to induce apoptosis in breast cancer cells

    Science.gov (United States)

    Pickard, Mark R.; Williams, Gwyn T.

    2016-01-01

    Growth arrest-specific 5 (GAS5) lncRNA promotes apoptosis, and its expression is down-regulated in breast cancer. GAS5 lncRNA is a decoy of glucocorticoid/related receptors; a stem-loop sequence constitutes the GAS5 hormone response element mimic (HREM), which is essential for the regulation of breast cancer cell apoptosis. This preclinical study aimed to determine if the GAS5 HREM sequence alone promotes the apoptosis of breast cancer cells. Nucleofection of hormone-sensitive and –insensitive breast cancer cell lines with a GAS5 HREM DNA oligonucleotide increased both basal and ultraviolet-C-induced apoptosis, and decreased culture viability and clonogenic growth, similar to GAS5 lncRNA. The HREM oligonucleotide demonstrated similar sequence specificity to the native HREM for its functional activity and had no effect on endogenous GAS5 lncRNA levels. Certain chemically modified HREM oligonucleotides, notably DNA and RNA phosphorothioates, retained pro-apoptotic. activity. Crucially the HREM oligonucleotide could overcome apoptosis resistance secondary to deficient endogenous GAS5 lncRNA levels. Thus, the GAS5 lncRNA HREM sequence alone is sufficient to induce apoptosis in breast cancer cells, including triple-negative breast cancer cells. These findings further suggest that emerging knowledge of structure/function relationships in the field of lncRNA biology can be exploited for the development of entirely novel, oligonucleotide mimic-based, cancer therapies. PMID:26862727

  16. Modeling of oxygen gas diffusion and consumption during the oxic transient in a disposal cell of radioactive waste

    International Nuclear Information System (INIS)

    De Windt, Laurent; Marsal, François; Corvisier, Jérôme; Pellegrini, Delphine

    2014-01-01

    Highlights: • This paper deals with the geochemistry of underground HLW disposals. • The oxic transient is a key issue in performance assessment (e.g. corrosion, redox). • A reactive transport model is explicitly coupled to gas diffusion and reactivity. • Application to in situ experiment (Tournemire laboratory) and HLW disposal cell. • Extent of the oxidizing/reducing front is investigated by sensitivity analysis. - Abstract: The oxic transient in geological radioactive waste disposals is a key issue for the performance of metallic components that may undergo high corrosion rates under such conditions. A previous study carried out in situ in the argillite formation of Tournemire (France) has suggested that oxic conditions could have lasted several years. In this study, a multiphase reactive transport model is performed with the code HYTEC to analyze the balance between the kinetics of pyrite oxidative dissolution, the kinetics of carbon steel corrosion and oxygen gas diffusion when carbon steel components are emplaced in the geological medium. Two cases were modeled: firstly, the observations made in situ have been reproduced, and the model established was then applied to a disposal cell for high-level waste (HLW) in an argillaceous formation, taking into account carbon steel components and excavated damaged zones (EDZ). In a closed system, modeling leads to a complete and fast consumption of oxygen in both cases. Modeling results are more consistent with the in situ test while considering residual voids between materials and/or a water unsaturated state allowing for oxygen gas diffusion (open conditions). Under similar open conditions and considering ventilation of the handling drifts, a redox contrast occurs between reducing conditions at the back of the disposal cell (with anoxic corrosion of steel and H 2 production) and oxidizing conditions at the front of the cell (with oxic corrosion of steel). The extent of the oxidizing/reducing front in the

  17. Gas-phase decontamination demonstration on PORTS cell X-25-4-2. Final technology status report

    International Nuclear Information System (INIS)

    Riddle, R.J.

    1997-09-01

    The Long-Term, Low Temperature (LTLT) process is a gas-phase in situ decontamination technique which has been tested by LMES/K-25 personnel on the laboratory scale with promising results. The purpose of the Gas-Phase Decontamination Demonstration at PORTS was to evaluate the LTLT process on an actual diffusion cascade cell at conditions similar to those used in the laboratory testing. The demonstration was conducted on PORTS diffusion cell X-25-4-2 which was one of the X-326 Building cells which was permanently shutdown as part of the Suspension of HEU Production at PORTS. The demonstration full-scale test consisted of rendering the cell leak-tight through the installation of Dresser seals onto the process seals, exposing the cell to the oxidants ClF 3 and F 2 for a period of 105 days and evaluating the effect of the clean-up treatment on cell samples and coupons representing the major diffusion cascade materials of construction. The results were extrapolated to determine the effectiveness of LTLT decontamination over the range of historical uranium isotope assays present in the diffusion complex. It was determined that acceptable surface contamination levels could be obtained in all of the equipment in the lower assay cascades which represents the bulk of the equipment contained in the diffusion complex

  18. Prediction of production of {sup 22}Na in a gas-cell target irradiated by protons using Monte Carlo tracking

    Energy Technology Data Exchange (ETDEWEB)

    Eslami, M., E-mail: mohammad.eslami25@yahoo.com [Department of Physics, Faculty of Science, University of Zanjan, Zengan (Zanjan) (Iran, Islamic Republic of); Kakavand, T. [Department of Physics, Faculty of Science, University of Zanjan, Zengan (Zanjan) (Iran, Islamic Republic of); Department of Physics, Faculty of Science, Imam Khomeini International University, Qazvin (Iran, Islamic Republic of); Mirzaii, M.; Rajabifar, S. [Agricultural, Medical and Industrial Research School, Nuclear Science and Technology Research Institute, AEOI, Karaj (Iran, Islamic Republic of)

    2015-01-01

    Highlights: • Angular distribution of the proton beam in a gaseous environment. • Particle energy distribution profile and proton flux within gas-cell target with MCNPX. • Detection of the residual nuclei during the nuclear reactions. • Estimation of production yield for {sup 22,nat}Ne(p,x){sup 22}Na reactions. - Abstract: The {sup 22}Ne(p,n){sup 22}Na is an optimal reaction for the cyclotron production of {sup 22}Na. This work tends to monitor the proton induced production of {sup 22}Na in a gas-cell target, containing natural and enriched neon gas, using Monte Carlo method. The excitation functions of reactions are calculated by both TALYS-1.6 and ALICE/ASH codes and then the optimum energy range of projectile for the high yield production is selected. A free gaseous environment of neon at a particular pressure and temperature is prearranged and the proton beam is transported within it using Monte Carlo codes MCNPX and SRIM. The beam monitoring performed by each of these codes indicates that the gas-cell has to be designed as conical frustum to reach desired interactions. The MCNPX is also employed to calculate the energy distribution of proton in the designed target and estimation of the residual nuclei during irradiation. The production yield of {sup 22}Na in {sup 22}Ne(p,n){sup 22}Na and {sup nat}Ne(p,x){sup 22}Na reactions are estimated and it shows a good agreement with the experimental results. The results demonstrate that Monte Carlo makes available a beneficial manner to design and optimize the gas targets as well as calibration of detectors, which can be used for the radionuclide production purposes.

  19. Dual gas-diffusion membrane- and mediatorless dihydrogen/air-breathing biofuel cell operating at room temperature

    Science.gov (United States)

    Xia, Hong-qi; So, Keisei; Kitazumi, Yuki; Shirai, Osamu; Nishikawa, Koji; Higuchi, Yoshiki; Kano, Kenji

    2016-12-01

    A membraneless direct electron transfer (DET)-type dihydrogen (H2)/air-breathing biofuel cell without any mediator was constructed wherein bilirubin oxidase from Myrothecium verrucaria (BOD) and membrane-bound [NiFe] hydrogenase from Desulfovibrio vulgaris Miyazaki F (MBH) were used as biocatalysts for the cathode and the anode, respectively, and Ketjen black-modified water proof carbon paper (KB/WPCC) was used as an electrode material. The KB/WPCC surface was modified with 2-aminobenzoic acid and p-phenylenediamine, respectively, to face the positively charged electron-accepting site of BOD and the negatively charged electron-donating site of MBH to the electrode surface. A gas-diffusion system was employed for the electrodes to realize high-speed substrate supply. As result, great improvement in the current density of O2 reduction with BOD and H2 reduction with MBH were realized at negatively and postively charged surfaces, respectively. Gas diffusion system also suppressed the oxidative inactivation of MBH at high electrode potentials. Finally, based on the improved bioanode and biocathode, a dual gas-diffusion membrane- and mediatorless H2/air-breathing biofuel cell was constructed. The maximum power density reached 6.1 mW cm-2 (at 0.72 V), and the open circuit voltage was 1.12 V using 1 atm of H2 gas as a fuel at room temperature and under passive and quiescent conditions.

  20. Fabricating method of gas diffusion electrode for fuel cell. Nenryo denchiyo gas kakusan denkyoku no seizo hoho

    Energy Technology Data Exchange (ETDEWEB)

    Harada, H [Yokohama (Japan)

    1994-01-28

    Cation exchange film is pressure bonded by hot-pressing on an aluminium foil for the solid high polymer electrolyte fuel cell which uses the cation exchange film as the electrolyte (PEMFC), but the conditions for the hot-pressing are severe because the softening temperature of polytetrafluoroethylene used as the binder for the bonding is higher than that of the cation exchange film. This invention is concerned with a method of improving adhesion and binding between the cation exchange film surface and the electrode catalyst layer, wherein K or Na type perfluorosulfonic acid system copolymer of the same material as that used for the cation exchange film is used as the binder in preparing the electrode catalyst layer of PEMFC, and the softening temperature of the cation exchange film itself is increased to enable high temperature hot-pressing. It is desirable to use the cation exchange film with the dry film thickness from 50 to 150[mu] and ion exchange capacity from 0.83 to 1.43 milli-equivalent/g (dry resin). 1 fig.

  1. Determining air quality and greenhouse gas impacts of hydrogen infrastructure and fuel cell vehicles.

    Science.gov (United States)

    Stephens-Romero, Shane; Carreras-Sospedra, Marc; Brouwer, Jacob; Dabdub, Donald; Samuelsen, Scott

    2009-12-01

    Adoption of hydrogen infrastructure and hydrogen fuel cell vehicles (HFCVs) to replace gasoline internal combustion engine (ICE) vehicles has been proposed as a strategy to reduce criteria pollutant and greenhouse gas (GHG) emissions from the transportation sector and transition to fuel independence. However, it is uncertain (1) to what degree the reduction in criteria pollutants will impact urban air quality, and (2) how the reductions in pollutant emissions and concomitant urban air quality impacts compare to ultralow emission gasoline-powered vehicles projected for a future year (e.g., 2060). To address these questions, the present study introduces a "spatially and temporally resolved energy and environment tool" (STREET) to characterize the pollutant and GHG emissions associated with a comprehensive hydrogen supply infrastructure and HFCVs at a high level of geographic and temporal resolution. To demonstrate the utility of STREET, two spatially and temporally resolved scenarios for hydrogen infrastructure are evaluated in a prototypical urban airshed (the South Coast Air Basin of California) using geographic information systems (GIS) data. The well-to-wheels (WTW) GHG emissions are quantified and the air quality is established using a detailed atmospheric chemistry and transport model followed by a comparison to a future gasoline scenario comprised of advanced ICE vehicles. One hydrogen scenario includes more renewable primary energy sources for hydrogen generation and the other includes more fossil fuel sources. The two scenarios encompass a variety of hydrogen generation, distribution, and fueling strategies. GHG emissions reductions range from 61 to 68% for both hydrogen scenarios in parallel with substantial improvements in urban air quality (e.g., reductions of 10 ppb in peak 8-h-averaged ozone and 6 mug/m(3) in 24-h-averaged particulate matter concentrations, particularly in regions of the airshed where concentrations are highest for the gasoline scenario).

  2. Methane Emissions from Landfill: Isotopic Evidence for Low Percentage of Oxidation from Gas Wells, Active and Closed Cells

    Science.gov (United States)

    Lowry, David; Fisher, Rebecca; Zazzeri, Giulia; al-Shalaan, Aalia; France, James; Lanoisellé, Mathias; Nisbet, Euan

    2017-04-01

    Large landfill sites remain a significant source of methane emissions in developed and developing countries, with a global estimated flux of 29 Tg / yr in the EDGAR 2008 database. This is significantly lower than 20 years ago due to the introduction of gas extraction systems, but active cells still emit significant amounts of methane before the gas is ready for extraction. Historically the methane was either passively oxidized through topsoil layers or flared. Oxidation is still the primary method of methane removal in many countries, and covered, remediated cells across the world continue to emit small quantities of methane. The isotopic signatures of methane from landfill gas wells, and that emitted from active and closed cells have been characterized for more than 20 UK landfills since 2011, with more recent work in Kuwait and Hong Kong. Since 2013 the emission plumes have been identified by a mobile measurement system (Zazzeri et al., 2015). Emissions in all 3 countries have a characteristic δ13C signature of -58 ± 3 ‰ dominated by emissions from the active cells, despite the hot, dry conditions of Kuwait and the hot, humid conditions of Hong Kong. Gas well samples define a similar range. Surface emissions from closed cells and closed landfills are mostly in the range -56 to -52 ‰Ṫhese are much more depleted values than those observed in the 1990s (up to -35 ) when soil oxidation was the dominant mechanism of methane removal. Calculations using isotopic signatures of the amount of methane oxidised in these closed areas before emission to atmosphere range from 5 to 15%, but average less than 10%, and are too small to calculate from the high-emitting active cells. Compared to other major methane sources, landfills have the most consistent isotopic signature globally, and are distinct from the more 13C-enriched natural gas, combustion and biomass burning sources. Zazzeri, G. et al. (2015) Plume mapping and isotopic characterization of anthropogenic methane

  3. Vapor Delivery Systems for the Study of the Effects of Reformate Gas Impurities in HT-PEM Fuel Cells

    DEFF Research Database (Denmark)

    Araya, Samuel Simon; Kær, Søren Knudsen; Andreasen, Søren Juhl

    2011-01-01

    , impurities in the reformate gas produced from methanol steam reforming can affect the performance and durability of fuel cells. In this paper different vapor delivery systems, intended to assist in the study of the effects of some of the impurities, are described and compared with each other. A system based...... on a pump and electrically heated evaporator was found to be more suitable for the typical flow rates involved in the anode feed of an H3PO4/PBI based HT-PEMFC unit cell assembly. Test stations composed of vapor delivery systems and mass flow controllers for testing the effects of methanol slip, water vapor...

  4. Post-test analysis of 20kW molten carbonate fuel cell stack operated on coal gas. Final report, August 1993--February 1996

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-05-01

    A 20kW carbonate fuel cell stack was operated with coal gas for the first time in the world. The stack was tested for a total of 4,000 hours, of which 3,900 hours of testing was conducted at the Louisiana Gasification Technology Incorporated, Plaquemine, Louisiana outdoor site. The operation was on either natural gas or coal gas and switched several times without any effects, demonstrating duel fuel capabilities. This test was conducted with 9142 kJ/m{sup 3} (245 Btu/cft) coal gas provided by a slipstream from Destec`s entrained flow, slagging, slurry-fed gasifier equipped with a cold gas cleanup subsystem. The stack generated up to 21 kW with this coal gas. Following completion of this test, the stack was brought to Energy Research Corporation (ERC) and a detailed post-test analysis was conducted to identify any effects of coal gas on cell components. This investigation has shown that the direct fuel cell (DFC) can be operated with properly cleaned and humidified coal-as, providing stable performance. The basic C direct fuel cell component materials are stable and display normal stability in presence of the coal gas. No effects of the coal-borne contaminants are apparent. Further cell testing at ERC 1 17, confirmed these findings.

  5. Versatile, ultra-low sample volume gas analyzer using a rapid, broad-tuning ECQCL and a hollow fiber gas cell

    Science.gov (United States)

    Kriesel, Jason M.; Makarem, Camille N.; Phillips, Mark C.; Moran, James J.; Coleman, Max L.; Christensen, Lance E.; Kelly, James F.

    2017-05-01

    We describe a versatile mid-infrared (Mid-IR) spectroscopy system developed to measure the concentration of a wide range of gases with an ultra-low sample size. The system combines a rapidly-swept external cavity quantum cascade laser (ECQCL) with a hollow fiber gas cell. The ECQCL has sufficient spectral resolution and reproducibility to measure gases with narrow features (e.g., water, methane, ammonia, etc.), and also the spectral tuning range needed to measure volatile organic compounds (VOCs), (e.g., aldehydes, ketones, hydrocarbons), sulfur compounds, chlorine compounds, etc. The hollow fiber is a capillary tube having an internal reflective coating optimized for transmitting the Mid-IR laser beam to a detector. Sample gas introduced into the fiber (e.g., internal volume = 0.6 ml) interacts strongly with the laser beam, and despite relatively modest path lengths (e.g., L 3 m), the requisite quantity of sample needed for sensitive measurements can be significantly less than what is required using conventional IR laser spectroscopy systems. Example measurements are presented including quantification of VOCs relevant for human breath analysis with a sensitivity of 2 picomoles at a 1 Hz data rate.

  6. The origin of the selectivity and activity of ruthenium-cluster catalysts for fuel-cell feed-gas purification: a gas-phase approach.

    Science.gov (United States)

    Lang, Sandra M; Bernhardt, Thorsten M; Krstić, Marjan; Bonačić-Koutecký, Vlasta

    2014-05-19

    Gas-phase ruthenium clusters Ru(n)(+) (n=2-6) are employed as model systems to discover the origin of the outstanding performance of supported sub-nanometer ruthenium particles in the catalytic CO methanation reaction with relevance to the hydrogen feed-gas purification for advanced fuel-cell applications. Using ion-trap mass spectrometry in conjunction with first-principles density functional theory calculations three fundamental properties of these clusters are identified which determine the selectivity and catalytic activity: high reactivity toward CO in contrast to inertness in the reaction with CO2; promotion of cooperatively enhanced H2 coadsorption and dissociation on pre-formed ruthenium carbonyl clusters, that is, no CO poisoning occurs; and the presence of Ru-atom sites with a low number of metal-metal bonds, which are particularly active for H2 coadsorption and activation. Furthermore, comprehensive theoretical investigations provide mechanistic insight into the CO methanation reaction and discover a reaction route involving the formation of a formyl-type intermediate. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Versatile, ultra-low sample volume gas analyzer using a rapid, broad-tuning ECQCL and a hollow fiber gas cell

    Energy Technology Data Exchange (ETDEWEB)

    Kriesel, Jason M.; Makarem, Camille N.; Phillips, Mark C.; Moran, James J.; Coleman, Max; Christensen, Lance; Kelly, James F.

    2017-05-05

    We describe a versatile mid-infrared (Mid-IR) spectroscopy system developed to measure the concentration of a wide range of gases with an ultra-low sample size. The system combines a rapidly-swept external cavity quantum cascade laser (ECQCL) with a hollow fiber gas cell. The ECQCL has sufficient spectral resolution and reproducibility to measure gases with narrow features (e.g., water, methane, ammonia, etc.), and also the spectral tuning range needed to measure volatile organic compounds (VOCs), (e.g., aldehydes, ketones, hydrocarbons), sulfur compounds, chlorine compounds, etc. The hollow fiber is a capillary tube having an internal reflective coating optimized for transmitting the Mid-IR laser beam to a detector. Sample gas introduced into the fiber (e.g., internal volume = 0.6 ml) interacts strongly with the laser beam, and despite relatively modest path lengths (e.g., L ~ 3 m), the requisite quantity of sample needed for sensitive measurements can be significantly less than what is required using conventional IR laser spectroscopy systems. Example measurements are presented including quantification of VOCs relevant for human breath analysis with a sensitivity of ~2 picomoles at a 1 Hz data rate.

  8. Air bio-battery with a gas/liquid porous diaphragm cell for medical and health care devices.

    Science.gov (United States)

    Arakawa, Takahiro; Xie, Rui; Seshima, Fumiya; Toma, Koji; Mitsubayashi, Kohji

    2018-04-30

    Powering future generations of medical and health care devices mandates the transcutaneous transfer of energy or harvesting energy from the human body fluid. Glucose-driven bio fuel cells (bio-batteries) demonstrate promise as they produce electrical energy from glucose, which is a substrate presents in physiological fluids. Enzymatic biofuel cells can convert chemical energy into electrical energy using enzymes as catalysts. In this study, an air bio-battery was developed for healthcare and medical applications, consisting of a glucose-driven enzymatic biofuel cell using a direct gas-permeable membrane or a gas/liquid porous diaphragm. The power generation characteristics included a maximum current density of 285μA/cm 2 and maximum power density of 70.7μW/cm 2 in the presence of 5mmol/L of glucose in solution. In addition, high-performance, long-term-stabilized power generation was achieved using the gas/liquid porous diaphragm for the reactions between oxygen and enzyme. This system can be powered using 5mmol/L of glucose, the value of which is similar to that of the blood sugar range in humans. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. CAD/CAM–designed 3D-printed electroanalytical cell for the evaluation of nanostructured gas-diffusion electrodes

    International Nuclear Information System (INIS)

    Chervin, Christopher N; Parker, Joseph F; Nelson, Eric S; Rolison, Debra R; Long, Jeffrey W

    2016-01-01

    The ability to effectively screen and validate gas-diffusion electrodes is critical to the development of next-generation metal–air batteries and regenerative fuel cells. The limiting electrode in a classic two-terminal device such as a battery or fuel cell is difficult to discern without an internal reference electrode, but the flooded electrolyte characteristic of three-electrode electroanalytical cells negates the prime function of an air electrode—a void volume freely accessible to gases. The nanostructured catalysts that drive the energy-conversion reactions (e.g., oxygen reduction and evolution in the air electrode of metal–air batteries) are best evaluated in the electrode structure as-used in the practical device. We have designed, 3D-printed, and characterized an air-breathing, thermodynamically referenced electroanalytical cell that allows us to mimic the Janus arrangement of the gas-diffusion electrode in a metal–air cell: one face freely exposed to gases, the other wetted by electrolyte. (paper)

  10. CAD/CAM-designed 3D-printed electroanalytical cell for the evaluation of nanostructured gas-diffusion electrodes

    Science.gov (United States)

    Chervin, Christopher N.; Parker, Joseph F.; Nelson, Eric S.; Rolison, Debra R.; Long, Jeffrey W.

    2016-04-01

    The ability to effectively screen and validate gas-diffusion electrodes is critical to the development of next-generation metal-air batteries and regenerative fuel cells. The limiting electrode in a classic two-terminal device such as a battery or fuel cell is difficult to discern without an internal reference electrode, but the flooded electrolyte characteristic of three-electrode electroanalytical cells negates the prime function of an air electrode—a void volume freely accessible to gases. The nanostructured catalysts that drive the energy-conversion reactions (e.g., oxygen reduction and evolution in the air electrode of metal-air batteries) are best evaluated in the electrode structure as-used in the practical device. We have designed, 3D-printed, and characterized an air-breathing, thermodynamically referenced electroanalytical cell that allows us to mimic the Janus arrangement of the gas-diffusion electrode in a metal-air cell: one face freely exposed to gases, the other wetted by electrolyte.

  11. Malignant human cell transformation of Marcellus shale gas drilling flow back water

    OpenAIRE

    Yao, Yixin; Chen, Tingting; Shen, Steven S.; Niu, Yingmei; DesMarais, Thomas L; Linn, Reka; Saunders, Eric; Fan, Zhihua; Lioy, Paul; Kluz, Thomas; Chen, Lung-Chi; Wu, Zhuangchun; Costa, Max

    2015-01-01

    The rapid development of high-volume horizontal hydraulic fracturing for mining natural gas from shale has posed potential impacts on human health and biodiversity. The produced flow back waters after hydraulic stimulation is known to carry high levels of saline and total dissolved solids. To understand the toxicity and potential carcinogenic effects of these waste waters, flow back water from five Marcellus hydraulic fracturing oil and gas wells were analyzed. The physicochemical nature of t...

  12. Novel electrospun gas diffusion layers for polymer electrolyte membrane fuel cells: Part I. Fabrication, morphological characterization, and in situ performance

    Science.gov (United States)

    Chevalier, S.; Lavielle, N.; Hatton, B. D.; Bazylak, A.

    2017-06-01

    In this first of a series of two papers, we report an in-depth analysis of the impact of the gas diffusion layer (GDL) structure on the polymer electrolyte membrane (PEM) fuel cell performance through the use of custom GDLs fabricated in-house. Hydrophobic electrospun nanofibrous gas diffusion layers (eGDLs) are fabricated with controlled fibre diameter and alignment. The eGDLs are rendered hydrophobic through direct surface functionalization, and this molecular grafting is achieved in the absence of structural alteration. The fibre diameter, chemical composition, and electrical conductivity of the eGDL are characterized, and the impact of eGDL structure on fuel cell performance is analysed. We observe that the eGDL facilitates higher fuel cell power densities compared to a commercial GDL (Toray TGP-H-60) at highly humidified operating conditions. The ohmic resistance of the fuel cell is found to significantly increase with increasing inter-fiber distance. It is also observed that the addition of a hydrophobic treatment enhances membrane hydration, and fibres perpendicularly aligned to the channel direction may enhance the contact area between the catalyst layer and the GDL.

  13. New sub-Doppler absorption resonances in a thin gas cell produced by means of a running monochromatic wave

    International Nuclear Information System (INIS)

    Tajalli, H; Ahmadi, S; Izmailov, A Ch

    2002-01-01

    A theoretical investigation is carried out through the interaction of the plane running monochromatic light wave, having an arbitrary intensity, with atoms (molecules) of a rarefied gas in the plane cell (at the normal incidence of the wave). Cases of closed and open resonance transitions from the non-degenerate ground (or metastable) quantum level are considered. Possible sub-Doppler resonances are analysed in the wave absorption, caused by the transient establishment of the optical coherence on the transition, Rabi oscillations between its levels, and optical pumping during the free flights of particles between the walls of the cell. Results of the previous works on given problems are generalized, which were obtained at definite restrictions on the wave intensity and cell length. Moreover, non-trivial sub-Doppler spectral structures, resulting as a consequence of the dependence of the absorption saturation on the transit relaxation of particles, have been established and investigated. Such structures may consist of a number of peaks and dips caused by Rabi oscillations between the transition levels. The results obtained can be used in sub-Doppler spectroscopy and for the stabilization of laser frequencies in thin gas cells

  14. Evaluation of landfill gas production and emissions in a MSW large-scale Experimental Cell in Brazil.

    Science.gov (United States)

    Maciel, Felipe Jucá; Jucá, José Fernando Thomé

    2011-05-01

    Landfill gas (LFG) emissions from municipal solid waste (MSW) landfills are an important environmental concern in Brazil due to the existence of several uncontrolled disposal sites. A program of laboratory and field tests was conducted to investigate gas generation in and emission from an Experimental Cell with a 36,659-ton capacity in Recife/PE - Brazil. This investigation involved waste characterisation, gas production and emission monitoring, and geotechnical and biological evaluations and was performed using three types of final cover layers. The results obtained in this study showed that waste decomposes 4-5 times faster in a tropical wet climate than predicted by traditional first-order models using default parameters. This fact must be included when considering the techniques and economics of projects developed in tropical climate countries. The design of the final cover layer and its geotechnical and biological behaviour proved to have an important role in minimising gas emissions to the atmosphere. Capillary and methanotrophic final cover layers presented lower CH(4) flux rates than the conventional layer. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. Performance analysis of hybrid solid oxide fuel cell and gas turbine cycle: Application of alternative fuels

    International Nuclear Information System (INIS)

    Zabihian, Farshid; Fung, Alan S.

    2013-01-01

    Highlights: • Variation of the stream properties in the syngas-fueled hybrid SOFC–GT cycle. • Detailed analysis of the operation of the methane-fueled SOFC–GT cycle. • Investigate effects of inlet fuel type and composition on performance of cycle. • Comparison of system operation when operated with and without anode recirculation. - Abstract: In this paper, the hybrid solid oxide fuel cell (SOFC) and gas turbine (GT) model was applied to investigate the effects of the inlet fuel type and composition on the performance of the cycle. This type of analysis is vital for the real world utilization of manufactured fuels in the hybrid SOFC–GT system due to the fact that these fuel compositions depends on the type of material that is processed, the fuel production process, and process control parameters. In the first part of this paper, it is shown that the results of a limited number of studies on the utilization of non-conventional fuels have been published in the open literature. However, further studies are required in this area to investigate all aspects of the issue for different configurations and assumptions. Then, the results of the simulation of the syngas-fueled hybrid SOFC–GT cycle are employed to explain the variation of the stream properties throughout the cycle. This analysis can be very helpful in understanding cycle internal working and can provide some interesting insights to the system operation. Then, the detailed information of the operation of the methane-fueled SOFC–GT cycle is presented. For both syngas- and methane-fueled cycles, the operating conditions of the equipment are presented and compared. Moreover, the comparison of the characteristics of the system when it is operated with two different schemes to provide the required steam for the cycle, with anode recirculation and with an external source of water, provides some interesting insights to the system operation. For instance, it was shown that although the physical

  16. Performance Comparison on Repowering of a Steam Power Plant with Gas Turbines and Solid Oxide Fuel Cells

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2016-01-01

    Repowering is a process for transforming an old power plant for greater capacity and/or higher efficiency. As a consequence, the repowered plant is characterized by higher power output and less specific CO2 emissions. Usually, repowering is performed by adding one or more gas turbines into an exi......Repowering is a process for transforming an old power plant for greater capacity and/or higher efficiency. As a consequence, the repowered plant is characterized by higher power output and less specific CO2 emissions. Usually, repowering is performed by adding one or more gas turbines...... into an existing steam cycle which was built decades ago. Thus, traditional repowering results in combined cycles (CC). High temperature fuel cells (such as solid oxide fuel cell (SOFC)) could also be used as a topping cycle, achieving even higher global plant efficiency and even lower specific CO2 emissions....... Decreasing the operating temperature in a SOFC allows the use of less complex materials and construction methods, consequently reducing plant and the electricity costs. A lower working temperature makes it also suitable for topping an existing steam cycle, instead of gas turbines. This is also the target...

  17. Greenhouse gas emission and exergy analyses of an integrated trigeneration system driven by a solid oxide fuel cell

    International Nuclear Information System (INIS)

    Chitsaz, Ata; Mahmoudi, S. Mohammad S.; Rosen, Marc A.

    2015-01-01

    Exergy and greenhouse gas emission analyses are performed for a novel trigeneration system driven by a solid oxide fuel cell (SOFC). The trigeneration system also consists of a generator-absorber heat exchanger (GAX) absorption refrigeration system and a heat exchanger to produce electrical energy, cooling and heating, respectively. Four operating cases are considered: electrical power generation, electrical power and cooling cogeneration, electrical power and heating cogeneration, and trigeneration. Attention is paid to numerous system and environmental performance parameters, namely, exergy efficiency, exergy destruction rate, and greenhouse gas emissions. A maximum enhancement of 46% is achieved in the exergy efficiency when the SOFC is used as the primary mover for the trigeneration system compared to the case when the SOFC is used as a standalone unit. The main sources of irreversibility are observed to be the air heat exchanger, the SOFC and the afterburner. The unit CO 2 emission (in kg/MWh) is considerably higher for the case in which only electrical power is generated. This parameter is reduced by half when the system is operates in a trigeneration mode. - Highlights: • A novel trigeneration system driven by a solid oxide fuel cell is analyzed. • Exergy and greenhouse gas emission analyses are performed. • Four special cases are considered. • An enhancement of up to 46% is achieved in exergy efficiency. • The CO 2 emission drops to a relatively low value for the tri-generation case

  18. Thin-film culturing technique allowing rapid gas-liquid equilibration (6 sec) with no toxicity to mammalian cells

    International Nuclear Information System (INIS)

    Koch, C.J.

    1984-01-01

    A method is described for inoculating mammalian cells onto the central area of glass petri dishes. The medium depth above the cells is only 100 μm for an added medium volume of 1 ml and increases linearly and rapidly with additional medium. The theoretical time constant for equilibration of the medium with the gas is related to the square of the medium depth. The experimental time constant was measured in two different ways for large and small medium depths, giving excellent agreement with the theoretical values. Although the time constant is only 6 sec for the case of 1 ml of added medium, there is no drying out of the medium or toxicity to the cells because of a large reservoir of medium in the meniscus at the periphery of the dish

  19. The fuel cell as a energy center. The chances of utilization of sewage gas; Die Brennstoffzelle als Energiezentrum. Die Chancen der Verwertung von Klaergas

    Energy Technology Data Exchange (ETDEWEB)

    Berger, P. [CFC Solutions GmbH, Muenchen (Germany)

    2008-07-01

    The basis of the fuel cell power station of the CFC Solutions GmbH (Munich, Federal Republic of Germany) is the carbonate fuel cell, with which arbitrary gaseous fuels can be used for power generation. The reformation of the methane containing gaseous fuel to hydrogen in the fuel cell requires heat energy, which is obtained as waste heat of the cell reaction. Apart from the electricity by the fuel cell power station heat energy is produced. Thus the fuel cell power station also can be used for the production of process steam and production of coldness by means of an absorption refrigeration system. A further advantage is that for the fuel cell power station no hydrogen have to be manufactured. In comparison to the motoric heat and power cogeneration or small gas turbines thee are further advantages for fuel cell power stations: a) high electrical efficiency within the kilowatt range; b) high temperature useful heat; c) efficient cooling; d) Flexibility with the fuel (natural gas, fermentation gas, sewage gas); e) good extent of utilization of the power station; f) flexible interpretation and operation according to user requirement; g) premium power and USV applications; g) smallest emission to exhaust gas and noises.

  20. Gas process technology for fuel cells. Desulfurization and other key problems; Gasprozesstechnik fuer Brennstoffzellen. Entschwefelung und andere Kernfragen

    Energy Technology Data Exchange (ETDEWEB)

    Heinzel, A.; Kalk, T.; Kvasnicka, A.; Roes, J.; Steffen, M.; Witzany, R. [Duisburg-Essen Univ., (Germany). ZBT Duisburg

    2008-07-01

    Fuel cells as Micro-CHP units for residential energy supply are one important technology option to improve energy efficiency and reduce emissions. Starting from natural gas as energy carrier, hydrogen is generated by catalytic processes. Prototypes are operated in field test in the meanwhile, but there are still important technical and scientific questions to deal with, as there are e.g. the desulfurisation of natural gas, the optimisation of heat integration in order to improve the efficiency of the complete system, the realisation of a closed water loop and last but not least the formation and impact of ammonia. At the same time, cost aspects and production technology have to be considered. (orig.)

  1. Cell for studying electron-adsorbed gas interactions; Cellule d'etudes des interactions electron-gaz adsorbe

    Energy Technology Data Exchange (ETDEWEB)

    Golowacz, H; Degras, D A [Commissariat a l' Energie Atomique, 91 - Saclay (France). Centre d' Etudes Nucleaires, Deptartement de Physique des Plasmas et de la Fusion Controlee, Service de Physique Appliquee, Service de Physique des Interractions Electroniques, Section d' Etude des Interactions Gaz-Solides

    1967-07-01

    The geometry and the technology of a cell used for investigations on electron-adsorbed gas interactions are described. The resonance frequencies of the surface ions which are created by the electron impact on the adsorbed gas are predicted by simplified calculations. The experimental data relative to carbon monoxide and neon are in good agreement with these predictions. (authors) [French] Les caracteristiques geometriques et technologiques generales d'une cellule d'etude des interactions entre un faisceau d'electrons et un gaz adsorbe sont donnees. Un calcul simplifie permet de prevoir les frequences de resonance des ions de surface crees par l'impact des electrons sur le gaz adsorbe. Les donnees experimentales sur l'oxyde de carbone et le neon confirment les previsions du calcul. (auteurs)

  2. Effects of a laser beam profile on Zeeman electromagnetically induced transparency in the Rb buffer gas cell

    International Nuclear Information System (INIS)

    Nikolić, S N; Radonjić, M; Krmpot, A J; Lučić, N M; Zlatković, B V; Jelenković, B M

    2013-01-01

    Electromagnetically induced transparency (EIT) due to Zeeman coherences in the Rb buffer gas cell is studied for different laser beam profiles, laser beam radii and intensities from 0.1 to 10 mW cm −2 . EIT line shapes can be approximated by the Lorentzian for wide Gaussian laser beam (6.5 mm in diameter) if laser intensity is weak and for a Π laser beam profile of the same diameter. Line shapes of EIT become non-Lorentzian for the Gaussian laser beam if it is narrow (1.3 mm in diameter) or if it has a higher intensity. EIT amplitudes and linewidths, for both laser beam profiles of the same diameter, have very similar behaviour regarding laser intensity and Rb cell temperature. EIT amplitudes are maximal at a certain laser beam intensity and this intensity is higher for narrower laser beams. The EIT linewidth estimated at zero laser intensity is about 50 nT or 0.7 kHz, which refers to 1.5 ms relaxation times of Zeeman coherences in 87 Rb atoms in our buffer gas cell. Blocking of the centre of the wide Gaussian laser beam in front of the photo detector yields Lorentzian profiles with a much better contrast to the linewidth ratio for EIT at higher intensities, above ∼2 mW cm −2 . (paper)

  3. Investigations on the double gas diffusion backing layer for performance improvement of self-humidified proton exchange membrane fuel cells

    International Nuclear Information System (INIS)

    Kong, Im Mo; Jung, Aeri; Kim, Min Soo

    2016-01-01

    Highlights: • The performance of self-humidified PEMFCs can be improved with double GDBL. • The effect of double GDBL on water retention capability and membrane hydration was investigated. • In addition to HFR and EIS measurements, numerical analysis was conducted. • Optimized design of double GDBL for self-humidified PEMFC was investigated. • This study provides an inspiration on how to design the double GDBL. - Abstract: In order to simplify the system configuration and downsize the volume, a proton exchange membrane fuel cell (PEMFC) needs to be operated in a self-humidified mode without any external humidifiers. However, in self-humidified PEMFCs, relatively low cell performance is a problem to be solved. In our previous study, a gas diffusion layer (GDL) containing double gas diffusion backing layer (GDBL) coated by single micro porous layer (MPL) was introduced and its effect on the cell performance was evaluated. In the present study, the effect of the double GDBL was investigated by measuring high frequency resistance (HFR) and electrochemical impedance spectroscopy (EIS). In the experiments, the HFR value was remarkably reduced, while the diameter of semicircle of EIS was increased. It means that the membrane hydration was improved due to enhanced water retention capability of the GDL despite of interrupted gas diffusion. The result of numerical analysis also showed that the water retention capability of GDL can be improved with proper structure design of double GDBL. Based on the result, optimized design of double GDBL for water retention was obtained numerically. The result of this study provides useful information on the structural design of GDBL for self-humidified PEMFCs.

  4. Measurement of IL-13–Induced iNOS-Derived Gas Phase Nitric Oxide in Human Bronchial Epithelial Cells

    Science.gov (United States)

    Suresh, Vinod; Mih, Justin D.; George, Steven C.

    2007-01-01

    Exhaled nitric oxide (NO) is altered in numerous diseases including asthma, and is thought broadly to be a noninvasive marker of inflammation. However, the precise source of exhaled NO has yet to be identified, and the interpretation is further hampered by significant inter-subject variation. Using fully differentiated normal human bronchial epithelial (NHBE) cells, we sought to determine (1) the rate of NO release (flux, pl·s−1.cm−2) into the gas; (2) the effect of IL-13, a prominent mediator of allergic inflammation, on NO release; and (3) inter-subject/donor variability in NO release. NHBE cells from three different donors were cultured at an air–liquid interface and stimulated with different concentrations of IL-13 (0, 1, and 10 ng/ml) for 48 h. Gas phase NO concentrations in the headspace over the cells were measured using a chemiluminescence analyzer. The basal NO flux from the three donors (0.05 ± 0.03) is similar in magnitude to that estimated from exhaled NO concentrations, and was significantly increased by IL-13 in a donor-specific fashion. The increase in NO release was strongly correlated with inducible nitric oxide synthase (iNOS) gene and protein expression. There was a trend toward enhanced production of nitrate relative to nitrite as an end product of NO metabolism in IL-13–stimulated cells. NO release from airway epithelial cells can be directly measured. The rate of release in response to IL-13 is strongly dependent on the individual donor, but is primarily due to the expression of iNOS. PMID:17347445

  5. Measurement of IL-13-induced iNOS-derived gas phase nitric oxide in human bronchial epithelial cells.

    Science.gov (United States)

    Suresh, Vinod; Mih, Justin D; George, Steven C

    2007-07-01

    Exhaled nitric oxide (NO) is altered in numerous diseases including asthma, and is thought broadly to be a noninvasive marker of inflammation. However, the precise source of exhaled NO has yet to be identified, and the interpretation is further hampered by significant inter-subject variation. Using fully differentiated normal human bronchial epithelial (NHBE) cells, we sought to determine (1) the rate of NO release (flux, pl.s(-1.)cm(-2)) into the gas; (2) the effect of IL-13, a prominent mediator of allergic inflammation, on NO release; and (3) inter-subject/donor variability in NO release. NHBE cells from three different donors were cultured at an air-liquid interface and stimulated with different concentrations of IL-13 (0, 1, and 10 ng/ml) for 48 h. Gas phase NO concentrations in the headspace over the cells were measured using a chemiluminescence analyzer. The basal NO flux from the three donors (0.05 +/- 0.03) is similar in magnitude to that estimated from exhaled NO concentrations, and was significantly increased by IL-13 in a donor-specific fashion. The increase in NO release was strongly correlated with inducible nitric oxide synthase (iNOS) gene and protein expression. There was a trend toward enhanced production of nitrate relative to nitrite as an end product of NO metabolism in IL-13-stimulated cells. NO release from airway epithelial cells can be directly measured. The rate of release in response to IL-13 is strongly dependent on the individual donor, but is primarily due to the expression of iNOS.

  6. Sulfur Poisoning of the Water Gas Shift Reaction on Anode Supported Solid Oxide Fuel Cells

    DEFF Research Database (Denmark)

    Hagen, Anke

    2013-01-01

    resistance increased both in the high and low frequency region, which indicates a strong poisoning of the water gas shift reaction and thus a lack of hydrogen fuel in addition to the poisoning of the electrochemical hydrogen oxidation. All poisoning effects are reversible under the applied operating...

  7. Two dimensional gas temperature measurements of fuel sprays in a high pressure cell

    NARCIS (Netherlands)

    Yu, M.

    2012-01-01

    Premixed charge compression ignition (PCCI) is a promising low-emission combustion concept. By partially mixing the fuel, air and exhaust gas before auto-ignition, the soot and NOx emissions are lower than for conventional diesel combustion. However, the fundamental aspects of the mixing process of

  8. Nonlinear empirical model of gas humidity-related voltage dynamics of a polymer-electrolyte-membrane fuel cell stack

    Science.gov (United States)

    Meiler, M.; Andre, D.; Schmid, O.; Hofer, E. P.

    suitable experimental setup to apply fast variations of gas humidity is introduced and is used to investigate a 10 cell PEMFC stack under various operation conditions. Using methods like stepwise multiple-regression a good mathematical description with reduced free parameters is achieved.

  9. Analysis and performance assessment of a new solar-based multigeneration system integrated with ammonia fuel cell and solid oxide fuel cell-gas turbine combined cycle

    Science.gov (United States)

    Siddiqui, Osamah; Dincer, Ibrahim

    2017-12-01

    In the present study, a new solar-based multigeneration system integrated with an ammonia fuel cell and solid oxide fuel cell-gas turbine combined cycle to produce electricity, hydrogen, cooling and hot water is developed for analysis and performance assessment. In this regard, thermodynamic analyses and modeling through both energy and exergy approaches are employed to assess and evaluate the overall system performance. Various parametric studies are conducted to study the effects of varying system parameters and operating conditions on the energy and exergy efficiencies. The results of this study show that the overall multigeneration system energy efficiency is obtained as 39.1% while the overall system exergy efficiency is calculated as 38.7%, respectively. The performance of this multigeneration system results in an increase of 19.3% in energy efficiency as compared to single generation system. Furthermore, the exergy efficiency of the multigeneration system is 17.8% higher than the single generation system. Moreover, both energy and exergy efficiencies of the solid oxide fuel cell-gas turbine combined cycle are determined as 68.5% and 55.9% respectively.

  10. Thermodynamic evaluation of hydrogen production for fuel cells by using bio-ethanol steam reforming: Effect of carrier gas addition

    Science.gov (United States)

    Hernández, Liliana; Kafarov, Viatcheslav

    Omitting the influence of the addition of carrier gas to the reaction system for hydrogen production by bio-ethanol steam reforming can lead to wrong conclusions, especially when it is going to be made to scale. The effect of carrier gas addition to produce hydrogen using bio-ethanol steam reforming to feed fuel cells was evaluated. Thermodynamic calculations in equilibrium conditions were made, however the analysis derived from them can also be applied to kinetic conditions. These calculations were made by using the Aspen-HYSYS software at atmospheric pressure and different values of temperature, water/ethanol molar ratios, and inert (argon)/(water/ethanol) molar ratios. The addition of inert carrier gas modifies the concentrations of the reaction products in comparison to those obtained without its presence. This behavior occurs because most of the reactions which take place in bio-ethanol steam reforming have a positive difference of moles. This fact enhances the system sensitivity to inert concentration at low and moderated temperatures (<700 °C). At high values of temperature, the inert addition does not influence the composition of the reaction products because of the predominant effect of inverse WGS reaction.

  11. Thermodynamic evaluation of hydrogen production for fuel cells by using bio-ethanol steam reforming: Effect of carrier gas addition

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, Liliana; Kafarov, Viatcheslav [Universidad Industrial de Santander, Escuela de Ingenieria Quimica, Bucaramanga 678 (Colombia)

    2009-07-01

    Omitting the influence of the addition of carrier gas to the reaction system for hydrogen production by bio-ethanol steam reforming can lead to wrong conclusions, especially when it is going to be made to scale. The effect of carrier gas addition to produce hydrogen using bio-ethanol steam reforming to feed fuel cells was evaluated. Thermodynamic calculations in equilibrium conditions were made, however the analysis derived from them can also be applied to kinetic conditions. These calculations were made by using the Aspen-HYSYS software at atmospheric pressure and different values of temperature, water/ethanol molar ratios, and inert (argon)/(water/ethanol) molar ratios. The addition of inert carrier gas modifies the concentrations of the reaction products in comparison to those obtained without its presence. This behavior occurs because most of the reactions which take place in bio-ethanol steam reforming have a positive difference of moles. This fact enhances the system sensitivity to inert concentration at low and moderated temperatures (<700 C). At high values of temperature, the inert addition does not influence the composition of the reaction products because of the predominant effect of inverse WGS reaction. (author)

  12. A study on volatile organic compounds emitted by in-vitro lung cancer cultured cells using gas sensor array and SPME-GCMS.

    Science.gov (United States)

    Thriumani, Reena; Zakaria, Ammar; Hashim, Yumi Zuhanis Has-Yun; Jeffree, Amanina Iymia; Helmy, Khaled Mohamed; Kamarudin, Latifah Munirah; Omar, Mohammad Iqbal; Shakaff, Ali Yeon Md; Adom, Abdul Hamid; Persaud, Krishna C

    2018-04-02

    Volatile organic compounds (VOCs) emitted from exhaled breath from human bodies have been proven to be a useful source of information for early lung cancer diagnosis. To date, there are still arguable information on the production and origin of significant VOCs of cancer cells. Thus, this study aims to conduct in-vitro experiments involving related cell lines to verify the capability of VOCs in providing information of the cells. The performances of e-nose technology with different statistical methods to determine the best classifier were conducted and discussed. The gas sensor study has been complemented using solid phase micro-extraction-gas chromatography mass spectrometry. For this purpose, the lung cancer cells (A549 and Calu-3) and control cell lines, breast cancer cell (MCF7) and non-cancerous lung cell (WI38VA13) were cultured in growth medium. This study successfully provided a list of possible volatile organic compounds that can be specific biomarkers for lung cancer, even at the 24th hour of cell growth. Also, the Linear Discriminant Analysis-based One versus All-Support Vector Machine classifier, is able to produce high performance in distinguishing lung cancer from breast cancer cells and normal lung cells. The findings in this work conclude that the specific VOC released from the cancer cells can act as the odour signature and potentially to be used as non-invasive screening of lung cancer using gas array sensor devices.

  13. DELIGHT-B/REDEL, point reactivity burnup code for high-temperature gas-cooled reactor cells

    International Nuclear Information System (INIS)

    Shindo, Ryuiti; Watanabe, Takashi.

    1977-03-01

    Code DELIGHT-2 was previously developed to analyze cell burnup characteristics and to produce few-group constants for core burnup calculation in high-temperature gas-cooled reactors. In the code, burnup dependency of the burnable poison, boron-10, is considered with the homogeneous model of space. In actuality, however, the burnable poison is used as homogeneous rods or uniform rods of small granular poison and graphite, to control the reactivity and power distribution. Precise analysis of the burnup characteristics is thus difficult because of the heterogeneity due to the configuration of poison rods. In cell burnup calculation, the DELIGHT-B, which is a modification of DELIGHT-2, takes into consideration this heterogeneous effect. The auxiliary code REDEL, a reduction of DELIGHT-B, used in combination with 3 dimensional diffusion code CITATION, is for core burnup calculation with the macro-scopic cross section model. (auth.)

  14. Sub-doppler spectroscopy based on the transit relaxation of atomic particles in a thin gas cell

    International Nuclear Information System (INIS)

    Izmailov, Azad

    2010-01-01

    This paper is the review of methods, achievements and possibilities of the recently elaborated high-resolution laser spectroscopy based on sub-doppler absorption, fluorescence and polarization resonances, which arise because of the specific optical selection of comparatively slow-speed atoms in a thin cell with rarefied gas. It was considered two following mechanisms of such a velocity selection of atomic particles connected with their flight durations between walls of the thin cell : 1) optical pumping of sublevels of the ground atomic term and 2) optical excitation of long-lived quantum levels. Theoretical bases of elaborated spectroscopy methods are presented. In case of the optical pumping mechanism, experimental technique and results on the record of sub-doppler spectral structure of Cs and Rb atoms and on the frequency stabilization of diode lasers by given methods are described. Perspectives of further development and applications of this new direction of the high-resolution spectroscopy are discussed

  15. Thermodynamic Modeling of a Solid Oxide Fuel Cell to Couple with an Existing Gas Turbine Engine Model

    Science.gov (United States)

    Brinson, Thomas E.; Kopasakis, George

    2004-01-01

    The Controls and Dynamics Technology Branch at NASA Glenn Research Center are interested in combining a solid oxide fuel cell (SOFC) to operate in conjunction with a gas turbine engine. A detailed engine model currently exists in the Matlab/Simulink environment. The idea is to incorporate a SOFC model within the turbine engine simulation and observe the hybrid system's performance. The fuel cell will be heated to its appropriate operating condition by the engine s combustor. Once the fuel cell is operating at its steady-state temperature, the gas burner will back down slowly until the engine is fully operating on the hot gases exhausted from the SOFC. The SOFC code is based on a steady-state model developed by The U.S. Department of Energy (DOE). In its current form, the DOE SOFC model exists in Microsoft Excel and uses Visual Basics to create an I-V (current-voltage) profile. For the project's application, the main issue with this model is that the gas path flow and fuel flow temperatures are used as input parameters instead of outputs. The objective is to create a SOFC model based on the DOE model that inputs the fuel cells flow rates and outputs temperature of the flow streams; therefore, creating a temperature profile as a function of fuel flow rate. This will be done by applying the First Law of Thermodynamics for a flow system to the fuel cell. Validation of this model will be done in two procedures. First, for a given flow rate the exit stream temperature will be calculated and compared to DOE SOFC temperature as a point comparison. Next, an I-V curve and temperature curve will be generated where the I-V curve will be compared with the DOE SOFC I-V curve. Matching I-V curves will suggest validation of the temperature curve because voltage is a function of temperature. Once the temperature profile is created and validated, the model will then be placed into the turbine engine simulation for system analysis.

  16. Gas explosions and thermal runaways during external heating abuse of commercial lithium-ion graphite-LiCoO2 cells at different levels of ageing

    Science.gov (United States)

    Larsson, Fredrik; Bertilsson, Simon; Furlani, Maurizio; Albinsson, Ingvar; Mellander, Bengt-Erik

    2018-01-01

    Commercial 6.8 Ah lithium-ion cells with different ageing/status have been abused by external heating in an oven. Prior to the abuse test, selected cells were aged either by C/2 cycling up to 300 cycles or stored at 60 °C. Gas emissions were measured by FTIR and three separate vents were identified, two well before the thermal runaway while the third occurred simultaneously with the thermal runaway releasing heavy smoke and gas. Emissions of toxic carbon monoxide (CO), hydrogen fluoride (HF) and phosphorous oxyfluoride (POF3) were detected in the third vent, regardless if there was a fire or not. All abused cells went into thermal runaway and emitted smoke and gas, the working cells also released flames as well as sparks. The dead cells were however less reactive but still underwent thermal runaway. For about half of the working cells, for all levels of cycle ageing, ignition of the accumulated battery released gases occurred about 15 s after the thermal runaway resulting in a gas explosion. The thermal runaway temperature, about 190 °C, varied somewhat for the different cell ageing/status where a weak local minimum was found for cells cycled between 100 and 200 times.

  17. Peclet number analysis of cross-flow in porous gas diffusion layer of polymer electrolyte membrane fuel cell (PEMFC).

    Science.gov (United States)

    Suresh, P V; Jayanti, Sreenivas

    2016-10-01

    Adoption of hydrogen economy by means of using hydrogen fuel cells is one possible solution for energy crisis and climate change issues. Polymer electrolyte membrane (PEM) fuel cell, which is an important type of fuel cells, suffers from the problem of water management. Cross-flow is induced in some flow field designs to enhance the water removal. The presence of cross-flow in the serpentine and interdigitated flow fields makes them more effective in proper distribution of the reactants on the reaction layer and evacuation of water from the reaction layer than diffusion-based conventional parallel flow fields. However, too much of cross-flow leads to flow maldistribution in the channels, higher pressure drop, and membrane dehydration. In this study, an attempt has been made to quantify the amount of cross-flow required for effective distribution of reactants and removal of water in the gas diffusion layer. Unit cells containing two adjacent channels with gas diffusion layer (GDL) and catalyst layer at the bottom have been considered for the parallel, interdigitated, and serpentine flow patterns. Computational fluid dynamics-based simulations are carried out to study the reactant transport in under-the-rib area with cross-flow in the GDL. A new criterion based on the Peclet number is presented as a quantitative measure of cross-flow in the GDL. The study shows that a cross-flow Peclet number of the order of 2 is required for effective removal of water from the GDL. Estimates show that this much of cross-flow is not usually produced in the U-bends of Serpentine flow fields, making these areas prone to flooding.

  18. Limiting Current of Oxygen Reduction on Gas-Diffusion Electrodes for Phosphoric Acid Fuel Cells

    DEFF Research Database (Denmark)

    Li, Qingfeng; Gang, Xiao; Hjuler, Hans Aage

    1994-01-01

    on polytetrafluorine-ethyl bonded gas-diffusion electordes in phosphoric acid with and without fluorinated additives. This provides an alternative to estimate the film thickness by combining it with the acid-adsorption measurements and the porosity analysis of the catalyst layer. It was noticed that the limiting......Various models have been devoted to the operation mechanism of porous diffusion electrodes. They are, however, suffering from the lack of accuracy concerning the acid-film thickness on which they are based. In the present paper the limiting current density has been measured for oxygen reduction...... current density can be accomplished either by gas-phase diffusion or liquid-phase diffusion, and it is the latter that can be used in the film-thickness estimation. It is also important to mention that at such a limiting condition, both the thin-film model and the filmed agglomerate model reach the same...

  19. Production of simplex RNS and ROS by nanosecond pulse N2/O2 plasma jets with homogeneous shielding gas for inducing myeloma cell apoptosis

    Science.gov (United States)

    Liu, Zhijie; Xu, Dehui; Liu, Dingxin; Cui, Qingjie; Cai, Haifeng; Li, Qiaosong; Chen, Hailan; Kong, Michael G.

    2017-05-01

    In this paper, atmospheric pressure N2/O2 plasma jets with homogeneous shielding gas excited by nanosecond pulse are obtained to generate simplex reactive nitrogen species (RNS) and reactive oxygen species (ROS), respectively, for the purpose of studying the simplex RNS and ROS to induce the myeloma cell apoptosis with the same discharge power. The results reveal that the cell death rate by the N2 plasma jet with N2 shielding gas is about two times that of the O2 plasma jet with O2 shielding gas for the equivalent treatment time. By diagnosing the reactive species of ONOO-, H2O2, OH and \\text{O}2- in medium, our findings suggest the cell death rate after plasma jets treatment has a positive correlation with the concentration of ONOO-. Therefore, the ONOO- in medium is thought to play an important role in the process of inducing myeloma cell apoptosis.

  20. Preparation of gas diffusion electrodes for high temperature PEM-type fuel cells

    Czech Academy of Sciences Publication Activity Database

    Mazur, P.; Mališ, J.; Paidar, M.; Schauer, Jan; Bouzek, K.

    2010-01-01

    Roč. 14, 1-3 (2010), s. 101-105 ISSN 1944-3994. [PERMEA 2009. Prague, 07.06.2009-11.06.2009] R&D Projects: GA ČR GA203/08/0465 Institutional research plan: CEZ:AV0Z40500505 Keywords : gas diffusion electrode * polymer electrolyte * ionic liquid Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.752, year: 2010

  1. Hydrogen Fueled Hybrid Solid Oxide Fuel Cell-Gas Turbine (SOFC-GT) System for Long-Haul Rail Application

    Science.gov (United States)

    Chow, Justin Jeff

    Freight movement of goods is the artery for America's economic health. Long-haul rail is the premier mode of transport on a ton-mile basis. Concerns regarding greenhouse gas and criteria pollutant emissions, however, have motivated the creation of annually increasing locomotive emissions standards. Health issues from diesel particulate matter, especially near rail yards, have also been on the rise. These factors and the potential to raise conventional diesel-electric locomotive performance warrants the investigation of using future fuels in a more efficient system for locomotive application. This research evaluates the dynamic performance of a Solid Oxide Fuel Cell-Gas Turbine (SOFC-GT) Hybrid system operating on hydrogen fuel to power a locomotive over a rail path starting from the Port of Los Angeles and ending in the City of Barstow. Physical constraints, representative locomotive operation logic, and basic design are used from a previous feasibility study and simulations are performed in the MATLAB Simulink environment. In-house controls are adapted to and expanded upon. Results indicate high fuel-to-electricity efficiencies of at least 54% compared to a conventional diesel-electric locomotive efficiency of 35%. Incorporation of properly calibrated feedback and feed-forward controls enables substantial load following of difficult transients that result from train kinematics while maintaining turbomachinery operating requirements and suppressing thermal stresses in the fuel cell stack. The power split between the SOFC and gas turbine is deduced to be a deterministic factor in the balance between capital and operational costs. Using hydrogen results in no emissions if renewable and offers a potential of 24.2% fuel energy savings for the rail industry.

  2. Design and optimization of a combined fuel reforming and solid oxide fuel cell system with anode off-gas recycling

    International Nuclear Information System (INIS)

    Lee, Tae Seok; Chung, J.N.; Chen, Yen-Cho

    2011-01-01

    Highlights: → In this work, an analytical, parametric study is performed to evaluate the feasibility and performance of a combined fuel reforming and SOFC system. → Specifically the effects of adding the anode off-gas recycling and recirculation components and the CO 2 absorbent unit are investigated. → The AOG recycle ratio increases with increasing S/C ratio and the addition of AOG recycle eliminates the need for external water consumption. → The key finding is that for the SOFC operating at 900 deg. C with the steam to carbon ratio at 5 and no AOG recirculation, the system efficiency peaks. - Abstract: An energy conversion and management concept for a combined system of a solid oxide fuel cell coupled with a fuel reforming device is developed and analyzed by a thermodynamic and electrochemical model. The model is verified by an experiment and then used to evaluate the overall system performance and to further suggest an optimal design strategy. The unique feature of the system is the inclusion of the anode off-gas recycle that eliminates the need of external water consumption for practical applications. The system performance is evaluated as a function of the steam to carbon ratio, fuel cell temperature, anode off gas recycle ratio and CO 2 adsorption percentage. For most of the operating conditions investigated, the system efficiency starts at around 70% and then monotonically decreases to the average of 50% at the peak power density before dropping down to zero at the limiting current density point. From an engineering application point of view, the proposed combined fuel reforming and SOFC system with a range of efficiency between 50% and 70% is considered very attractive. It is suggested that the optimal system is the one where the SOFC operates around 900 deg. C with S/C ratio higher than 3, maximum CO 2 capture, and minimum AOG recirculation.

  3. Technology Status and Expected Greenhouse Gas Emissions of Battery, Plug-In Hybrid, and Fuel Cell Electric Vehicles

    Science.gov (United States)

    Lipman, Timothy E.

    2011-11-01

    Electric vehicles (EVs) of various types are experiencing a commercial renaissance but of uncertain ultimate success. Many new electric-drive models are being introduced by different automakers with significant technical improvements from earlier models, particularly with regard to further refinement of drivetrain systems and important improvements in battery and fuel cell systems. The various types of hybrid and all-electric vehicles can offer significant greenhouse gas (GHG) reductions when compared to conventional vehicles on a full fuel-cycle basis. In fact, most EVs used under most condition are expected to significantly reduce lifecycle GHG emissions. This paper reviews the current technology status of EVs and compares various estimates of their potential to reduce GHGs on a fuel cycle basis. In general, various studies show that battery powered EVs reduce GHGs by a widely disparate amount depending on the type of powerplant used and the particular region involved, among other factors. Reductions typical of the United States would be on the order of 20-50%, depending on the relative level of coal versus natural gas and renewables in the powerplant feedstock mix. However, much deeper reductions of over 90% are possible for battery EVs running on renewable or nuclear power sources. Plug-in hybrid vehicles running on gasoline can reduce emissions by 20-60%, and fuel cell EV reduce GHGs by 30-50% when running on natural gas-derived hydrogen and up to 95% or more when the hydrogen is made (and potentially compressed) using renewable feedstocks. These are all in comparison to what is usually assumed to be a more advanced gasoline vehicle "baseline" of comparison, with some incremental improvements by 2020 or 2030. Thus, the emissions from all of these EV types are highly variable depending on the details of how the electric fuel or hydrogen is produced.

  4. The mode of lymphoblastoid cell death in response to gas phase cigarette smoke is dose-dependent

    Directory of Open Access Journals (Sweden)

    Baltatzis George E

    2009-09-01

    Full Text Available Abstract Background Cigarette smoke (CS is the main cause in the development of chronic obstructive pulmonary disease (COPD, the pathogenesis of which is related to an extended inflammatory response. In this study, we investigated the effect of low and high doses of gas phase cigarette smoke (GPS on cultured lymphocyte progenitor cells, using techniques to assess cell viability and to elucidate whether cells die of apoptosis or necrosis upon exposure to different doses of GPS. Methods In our approach we utilised a newly-established system of exposure of cells to GPS that is highly controlled, accurately reproducible and simulates CS dosage and kinetics that take place in the smokers' lung. This system was used to study the mode of cell death upon exposure to GPS in conjunction with a range of techniques widely used for cell death studies such as Annexin V staining, activation of caspase -3, cytoplasmic release of cytochrome C, loss of mitochondrial membrane potential and DNA fragmentation. Results Low doses of GPS induced specific apoptotic indexes in CCRF-CEM cells. Specifically, cytochrome C release and cleaved caspase-3 were detected by immunofluorescence, upon treatment with 1-3 puffs GPS. At 4 h post-exposure, caspase-3 activation was observed in western blot analysis, showing a decreasing pattern as GPS doses increased. Concomitant with this behaviour, a dose-dependent change in Δψm depolarization was monitored by flow cytometry 2 h post-exposure, while at 4 h Δψm collapse was observed at the higher doses, indicative of a shift to a necrotic demise. A reduction in DNA fragmentation events produced by 5 puffs GPS as compared to those provoked by 3 puffs GPS, also pointed towards a necrotic response at the higher dose of GPS. Conclusion Collectively, our results support that at low doses gas phase cigarette smoke induces apoptosis in cultured T-lymphocytes, whereas at high doses GPS leads to necrotic death, by-passing the characteristic

  5. Inverted Fuel Cell: Room-Temperature Hydrogen Separation from an Exhaust Gas by Using a Commercial Short-Circuited PEM Fuel Cell without Applying any Electrical Voltage.

    Science.gov (United States)

    Friebe, Sebastian; Geppert, Benjamin; Caro, Jürgen

    2015-06-26

    A short-circuited PEM fuel cell with a Nafion membrane has been evaluated in the room-temperature separation of hydrogen from exhaust gas streams. The separated hydrogen can be recovered or consumed in an in situ olefin hydrogenation when the fuel cell is operated as catalytic membrane reactor. Without applying an outer electrical voltage, there is a continuous hydrogen flux from the higher to the lower hydrogen partial pressure side through the Nafion membrane. On the feed side of the Nafion membrane, hydrogen is catalytically split into protons and electrons by the Pt/C electrocatalyst. The protons diffuse through the Nafion membrane, the electrons follow the short-circuit between the two brass current collectors. On the cathode side, protons and electrons recombine, and hydrogen is released. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Fiscal 1999 research cooperation project. Research cooperation on community-oriented practical photovoltaic power systems (Practical methane gas fermentation fuel cell power systems); 1999 nendo metan hakko gas nenryo denchi hatsuden system no jitsuyoka ni kansuru kenkyu kyoryoku

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    This report describes the research cooperation with developing countries on practical methane gas fermentation fuel cell power systems in 1999-2002. This research aims to construct the methane gas fermentation fuel cell power facility using livestock excreta which can supply power to the facility and peripheral areas. The facility controls various substance concentrations in waste water within environmental standards, and uses waste as compost. This project is very promising in use of environment-friendly energy, effective use of unused energy and power supply to unelectrified areas for China under serious conditions such as rapid increase in energy demand and various environment problems. There are such various issues to achieve this target as securing livestock (pig breeders) and excreta, and fermentation and recovery of suitable methane gas necessary for fuel cell power systems from excreta. This report is composed of 2 parts, (1) Current use of energy resources and use of unused energy in Guangdong province, and (2) Technical requirements for practical methane gas fermentation fuel cell power systems. (NEDO)

  7. A micro-scale model for predicting contact resistance between bipolar plate and gas diffusion layer in PEM fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Y.; Lin, G.; Shih, A.J.; Hu, S.J. [Department of Mechanical Engineering, The University of Michigan, Ann Arbor, MI 48109-2125 (United States)

    2007-01-01

    Contact resistance between the bipolar plate (BPP) and the gas diffusion layer (GDL) in a proton exchange membrane (PEM) fuel cell constitutes a significant portion of the overall fuel cell electrical resistance under the normal operation conditions. Most current methods for contact resistance estimation are experimental and there is a lack of well developed theoretical methods. A micro-scale numerical model is developed to predict the electrical contact resistance between BPP and GDL by simulating the BPP surface topology and GDL structure and numerically determining the status for each contact spot. The total resistance and pressure are obtained by considering all contact spots as resistances in parallel and summing the results together. This model shows good agreements with experimental results. Influences of BPP surface roughness parameters on contact resistance are also studied. This model is beneficial in understanding the contact behavior between BPP and GDL and can be integrated with other fuel cell simulations to predict the overall performance of PEM fuel cells. (author)

  8. Gas and Gas Pains

    Science.gov (United States)

    ... to produce gas. Often, relatively simple changes in eating habits can lessen bothersome gas. Certain digestive system disorders, ... such as soda and beer, increase stomach gas. Eating habits, such as eating too quickly, drinking through a ...

  9. World`s first fuel cell in a single-family home - The VNG natural gas house: Low-emission energy meets all household needs

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1999-03-01

    VNG - Verbundnetz Gas Aktiengesellschaft of Leipzig, Germany, has pioneered the development of a decentral home energy system combining very high efficiencies with extremely low emissions. The company has installed the world`s first fuel cell total energy system using natural gas as an energy source to generate both heat and power in a single-family home. It replaces the gas-fired mini power station operated as part of the VNG natural gas house project which was instrumental in the rapid advancement of small-scale co-generation technology. The objective of VNG and its project partners is to collect reliable data for advancing fuel cell technology development, allowing appliance manufacturers to design a competitive system for introduction on the market within a few years. Discerning consumers will then be able to opt for an innovative, highly efficient system to meet all their household energy needs. (orig.)

  10. Cell proliferation in rat nasal respiratory epithelium following three months exposure to formaldehyde gas

    International Nuclear Information System (INIS)

    Monticello, T.M.; Morgan, K.T.

    1990-01-01

    Formaldehyde (HCHO), a ubiquitous chemical and rat nasal carcinogen, enhances cell proliferation in rat, monkey, and xenotransplanted human respiratory epithelium following short-term exposure. The present studies were designed to evaluate cell proliferation in relation to tumor induction in rat nasal respiratory epithelium following subchronic HCHO exposure. Male F-344 rats were whole-body exposed to either 0, 0.7, 2, 6, 10, or 15 ppm HCHO, for wither 4 d (6hr/d), 6 wks (5d/wk) or 3 months. Animals were labeled with tritiated thymidine prior to euthanasia. Nasal sections were processed for autoradiography and cell proliferation data was expressed as unit length labeling indices (ULLI). HCHO-induced lesions and increases in cell proliferation occurred in specific regions of the nose, primarily the wall of the lateral meatus and nasal septum of the anterior nasal cavity. Following 4 d exposure, significant elevations in cell proliferation were observed only in the 6, 10 and 15 ppm groups (16-, 18-, and 20-fold increase over control, respectively). Increases in ULLI were also present in the 6, 10 and 15 ppm groups after 6 wks of exposure (12-, 35-, and 40-fold increase over control). However, after 3 months exposure, elevations in ULLI were present only in the 10 and 15 ppm groups (9- and 14-fold increase over controls). These results demonstrate that (1) low levels of HCHO (0.7 and 2 ppm) do not increase cell proliferation in rat nasal respiratory epithelium; (2) 6 ppm HCHO induces transient increases in cell proliferation; and (3) clearly carcinogenic concentrations of HCHO (10 and 15 ppm) cause sustained elevations in cell proliferation which may play an important role in HCHO-induced carcinogenesis

  11. CD11c-targeted Delivery of DNA to Dendritic Cells Leads to cGAS- and STING-dependent Maturation

    DEFF Research Database (Denmark)

    Laursen, Marlene F.; Christensen, Esben; Degn, Laura L.T.

    2018-01-01

    monocyte-derived dendritic cells (moDC) and human monocytic THP-1 cells to targeted and untargeted DNA. We used an anti-CD11c antibody conjugated with double-stranded DNA to analyze the maturation status of human moDCs, as well as maturation using a cGAS KO and STING KO THP-1 cell maturation model. We...... with boosting the existing tumor-specific T-cell response. One way to achieve this could be by increasing the level of maturation of dendritic cells locally and in the draining lymph nodes. When exposed to cancer cells, dendritic cells may spontaneously mature because of dangerassociated molecular patterns...... derived from the tumor cells. Doublestranded DNA play a particularly important role in the activation of the dendritic cells, through engagement of intracellular DNAsensors, and signaling through the adaptor protein STING. In the present study, we have investigated the maturational response of human...

  12. Computational Fluid Dynamics-Population Balance Model Simulation of Effects of Cell Design and Operating Parameters on Gas-Liquid Two-Phase Flows and Bubble Distribution Characteristics in Aluminum Electrolysis Cells

    Science.gov (United States)

    Zhan, Shuiqing; Wang, Junfeng; Wang, Zhentao; Yang, Jianhong

    2018-02-01

    The effects of different cell design and operating parameters on the gas-liquid two-phase flows and bubble distribution characteristics under the anode bottom regions in aluminum electrolysis cells were analyzed using a three-dimensional computational fluid dynamics-population balance model. These parameters include inter-anode channel width, anode-cathode distance (ACD), anode width and length, current density, and electrolyte depth. The simulations results show that the inter-anode channel width has no significant effect on the gas volume fraction, electrolyte velocity, and bubble size. With increasing ACD, the above values decrease and more uniform bubbles can be obtained. Different effects of the anode width and length can be concluded in different cell regions. With increasing current density, the gas volume fraction and electrolyte velocity increase, but the bubble size keeps nearly the same. Increasing electrolyte depth decreased the gas volume fraction and bubble size in particular areas and the electrolyte velocity increased.

  13. Clinical value of determination of changes of serum Gas, IL-2, IL-10 and IL-18 levels after transfusion of Red blood cells in patients with peptic ulcer

    International Nuclear Information System (INIS)

    Liu Tingting; Li Xinghua

    2011-01-01

    Objective: To investigation the changes of serum Gas, IL-2, IL-10 and IL-18 contents after transfusion of red blood cells in patients with peptic ulcer. Methods: Serum Gas, IL-2, IL-10 (with RIA), serum IL-18 (with ELISA) levels were measured in 31 patients with peptic ulcer and 35 controls. Results: Before transfusion,the serum IL-2 level in the patients was significantly lower than that in controls (P 0.05). Conclusion: Detection of serum Gas, IL-2, IL-10 and IL-18 levels is clinically useful for monitoring progress and favourable prognosis of patients with peptic ulcer possess important clinical value. (authors)

  14. Numerical evaluation of various gas and coolant channel designs for high performance liquid-cooled proton exchange membrane fuel cell stacks

    International Nuclear Information System (INIS)

    Sasmito, Agus P.; Kurnia, Jundika C.; Mujumdar, Arun S.

    2012-01-01

    A careful design of gas and coolant channel is essential to ensure high performance and durability of proton exchange membrane (PEM) fuel cell stack. The channel design should allow for good thermal, water and gas management whilst keeping low pressure drop. This study evaluates numerically the performance of various gas and coolant channel designs simultaneously, e.g. parallel, serpentine, oblique-fins, coiled, parallel-serpentine and a novel hybrid parallel-serpentine-oblique-fins designs. The stack performance and local distributions of key parameters are investigated with regards to the thermal, water and gas management. The results indicate that the novel hybrid channel design yields the best performance as it constitutes to a lower pumping power and good thermal, water and gas management as compared to conventional channels. Advantages and limitation of the designs are discussed in the light of present numerical results. Finally, potential application and further improvement of the design are highlighted. -- Highlights: ► We evaluate various gas and coolant channel designs in liquid-cooled PEM fuel cell stack. ► The model considers coupled electrochemistry, channel design and cooling effect simultaneously. ► We propose a novel hybrid channel design. ► The novel hybrid channel design yields the best thermal, water and gas management which is beneficial for long term durability. ► The novel hybrid channel design exhibits the best performance.

  15. Power, heat and chilliness with natural gas - fuel cells and air conditioning

    International Nuclear Information System (INIS)

    Krein, Stephan; Ruehling, Karin

    1999-01-01

    A new and innovative concept of the supply with power, heat and chilliness will realise in the new Malteser-hospital in Kamenz. The core of this demonstration-plant are a fuel cell, an adsorption cooling machine as well as multi-solar collectors. The fuel cell has two goals. Primary it produces power for the own demand. The selected dimension guarantees, that the power will consume nearly continuously. Secondly the produced heat of the fuel cell (and the solar-heat too) will use for heating and preparation of warm water. In the summer, the heat will use for the adsorption cooling machine, which produces chilliness for air-conditioning. The advantage in the face of common concepts of combining power and heat is the high-efficiently use of the fuel-energy for electric power generation on the one hand. Fuel cells work with high efficiency also at partial load. On the other hand, with the adsorption cooling machine the produced heat of fuel cell and multi-solar collectors can be used also in the summer. First experiences with this concept show, that an optimised co-operation of the components with an adaptive, self-learning control system based on the weather forecast as well as various storages for heat and chilliness can be achieve. A continuously operation, high fuel utilisation and reduced environmental pollution can be demonstrated. (author)

  16. Experimental study on the self-humidification effect in proton exchange membrane fuel cells containing double gas diffusion backing layer

    International Nuclear Information System (INIS)

    Kong, Im Mo; Choi, Jong Won; Kim, Sung Il; Lee, Eun Sook; Kim, Min Soo

    2015-01-01

    Highlights: • Investigated self-humidification effect of structurally modified GDBLs in PEMFCs. • One conventional and two modified GDLs were prepared. • Structural design of the GDBLs significantly affected self-humidification. • Stacking was found to have negligible effect on self-humidification. • It can be applied readily to self-humidified PEMFCs. - Abstract: Adequate hydration of the membrane is required to ensure high proton conductivity in proton exchange membrane fuel cells (PEMFCs), which, in turn, is required for achieving high cell performances. While external humidifiers are typically used to humidify the supplied air in conventional systems, their use increases the complexity, weight, volume, and parasitic power loss in fuel cell systems, rendering them unviable in some systems, particularly for portable applications. In this study, the structure of a gas diffusion backing layer (GDBL) was modified to enhance the self-humidification effect in PEMFCs. Three types of GDLs were prepared for the experiments: a conventional GDL (GDL-A with uniform single GDBL) and two modified GDLs (GDL-A′B with uniform double GDBL and GDL-A′C with heterogeneous double GDBLs). In order to evaluate the effect of stacking and structural design on the self-humidification characteristics, some characteristics of the GDLs such as contact angle, resistance, and vapor permeation rate were measured. The electrochemical performances of the fuel cells were also measured at various relative humidity (RH) and stoichiometric ratio (SR) conditions. The results showed that stacking had a negligible effect, whereas the structural design of the GDBL had a significant effect on self-humidification. The self-humidification effect and the cell performance were improved significantly in the structurally modified GDBL. In addition, considering the actual field conditions and the results of the present study, it was concluded that the structural modifications made to the GDBL would

  17. Investigations on the carbon contaminations on the alkali cells of DPAL with hydrocarbon buffer gas

    Science.gov (United States)

    Li, Zhiyong; Tan, Rongqing; Wang, Yujie; Ye, Qing; Bian, Jintian; Huang, Wei; Li, Hui; Han, Gaoce

    2017-10-01

    Diode pumped alkali laser (DPAL) with hydrocarbon buffer gases has the features of low threshold and high efficiency. The chemical reaction between alkali and hydrocarbon gases affects the life time of DPAL. In this paper, a method based on Fourier transform infrared spectroscopy and Lambert-Beer law is adopted to find a safe temperature at which DPAL runs for a long term. A theoretical model is established to figure out ways to reduce the peak temperature in the cell window. The results indicates that 170 °C is a safe temperature. Although the absorbance of the cell window to the pump light and alkali laser is lower, there is temperature increase. Small light-transmitting area and air blowing on the windows can reduce the peak temperature effectively. Cooling the cell window is essential and critical in a long-term running DPAL.

  18. Stability and performance improvement of a polymer electrolyte membrane fuel cell stack by laser perforation of gas diffusion layers

    Energy Technology Data Exchange (ETDEWEB)

    Gerteisen, Dietmar; Sadeler, Christian [Fraunhofer Institute for Solar Energy Systems ISE, Department of Energy Technology, Heidenhofstrasse 2, 79110 Freiburg (Germany)

    2010-08-15

    The performance and stability of a hydrogen-driven polymer electrolyte membrane fuel cell stack (6-cell PEFC stack) are investigated with regard to pore flooding within the gas diffusion layers (GDLs). Two short stacks with various GDLs (Toray TGP-H-060 untreated and laser-perforated) were characterized at different operating conditions by several characterization techniques such as constant current load, polarization curve, chronoamperometry and chronovoltammetry. The experimental results reveal that the perforation of the cathode GDLs improves the water transport in the porous media and thus the performance as well as the stability of the operating stack in medium and high current density range. A reduced pore flooding is verified when using the customized laser-perforated GDLs. The GDL perforation has a huge potential to balance the inhomogeneous in-plane saturation conditions between the inlet and outlet area of the cell and to compensate to a certain degree the effects of temperature distribution within a stack regarding the water management. (author)

  19. Stability and performance improvement of a polymer electrolyte membrane fuel cell stack by laser perforation of gas diffusion layers

    Science.gov (United States)

    Gerteisen, Dietmar; Sadeler, Christian

    The performance and stability of a hydrogen-driven polymer electrolyte membrane fuel cell stack (6-cell PEFC stack) are investigated with regard to pore flooding within the gas diffusion layers (GDLs). Two short stacks with various GDLs (Toray TGP-H-060 untreated and laser-perforated) were characterized at different operating conditions by several characterization techniques such as constant current load, polarization curve, chronoamperometry and chronovoltammetry. The experimental results reveal that the perforation of the cathode GDLs improves the water transport in the porous media and thus the performance as well as the stability of the operating stack in medium and high current density range. A reduced pore flooding is verified when using the customized laser-perforated GDLs. The GDL perforation has a huge potential to balance the inhomogeneous in-plane saturation conditions between the inlet and outlet area of the cell and to compensate to a certain degree the effects of temperature distribution within a stack regarding the water management.

  20. Effect of carbon paper substrate of the gas diffusion layer on the performance of proton exchange membrane fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Lin, J.F. [Fuel Cell Research Lab, Engineering Technology Department, Arizona State University, Mesa, AZ 85212 (United States); Wertz, J. [Hollingsworth and Vose Co., A.K. Nicholson Research Lab, 219 Townsend Road, West Groton, MA 01472 (United States); Ahmad, R.; Thommes, M. [Quantachrome Instruments, 1900 Corporate Drive, Boynton Beach, FL 33426 (United States); Kannan, A.M., E-mail: amk@asu.ed [Fuel Cell Research Lab, Engineering Technology Department, Arizona State University, Mesa, AZ 85212 (United States)

    2010-03-01

    Gas diffusion layers (GDLs) were fabricated using non-woven carbon paper substrates with various thicknesses developed by Hollingsworth and Vose Co. Highly consistent carbon slurry containing Pureblack carbon and vapor grown carbon fiber (3:1 ratio) with 25 wt.% Teflon was prepared by using a dispersion agent, Novec-7300 in isopropyl alcohol. Micro-porous layer was coated by using a fully automated Coatema coating tool with a uniform carbon loading of 2.6-3 mg cm{sup -2} using carbon slurry. The surface morphology, contact angle and pore size distribution of the GDLs were examined using SEM, Goniometer and Hg Porosimeter, respectively. Various cathode GDLs assembled into MEAs were evaluated in a single cell PEMFC under various operating relative humidity (RH) conditions using H{sub 2}/O{sub 2} and H{sub 2}/air as reactants. The peak power density of the single cell using the optimum carbon paper substrate thickness was about 1400 and 700 mW cm{sup -2} with H{sub 2}/O{sub 2} and H{sub 2}/air at 60% RH, respectively. It was found that the pore diameter as well as the corresponding pore volumes of the GDLs played a key role in exhibiting the optimum fuel cell performance.

  1. Ion-neutral gas reactions in a collision/reaction cell in inductively coupled plasma mass spectrometry: Correlation of ion signal decrease to kinetic rate constants

    Energy Technology Data Exchange (ETDEWEB)

    Gray, Patrick J. [Trace Element Research Laboratory, School of Earth Sciences, The Ohio State University, 125 S. Oval Mall, Columbus, OH 43210 (United States); Department of Chemistry, The Ohio State University, 120 18th Avenue, Columbus, OH 43210 (United States); Olesik, John W., E-mail: olesik.2@osu.edu [Trace Element Research Laboratory, School of Earth Sciences, The Ohio State University, 125 S. Oval Mall, Columbus, OH 43210 (United States)

    2015-03-01

    Reaction gas flow rate dependent Ar{sub 2}{sup +} and Ar{sup +} signals are correlated to fundamental kinetic rate coefficients. A simple calculation, assuming that gas exits the reaction cell due only to effusion, is described to estimate the gas pressure in the reaction cell. The value of the product of the kinetic rate constant and the ion residence time in the reaction cell can be determined from experimental measurement of the decrease in an ion signal as a function of reaction gas flow rate. New kinetic rate constants are determined for the reaction of CH{sub 3}F with Ar{sup +} and Ar{sub 2}{sup +}. - Highlights: • How to determine pressure and the product of the kinetic rate constant times the ion residence time in reaction cell • Relate measured ICP-DRC-MS signals versus gas flow rate to kinetic rate constants measured previously using SIFT-MS • Describe how to determine previously unmeasured kinetic rate constants using ICP-DRC-MS.

  2. Influence of artificially aged gas diffusion layers on the water management of polymer electrolyte membrane fuel cells analyzed with in-operando synchrotron imaging

    International Nuclear Information System (INIS)

    Arlt, Tobias; Klages, Merle; Messerschmidt, Matthias; Scholta, Joachim; Manke, Ingo

    2017-01-01

    The influence of artificial ageing of gas diffusion layers (GDLs) on the cell performance was investigated using high resolution synchrotron radiography. State-of-the-art GDLs of the type SIGRACET ® SGL 25BC were aged for 0 h, 16 h and 24 h in a hydrogen peroxide solution before they were assembled in the fuel cells. In-operando radiographic measurements were combined with voltage and contact angle measurements. Correlations between applied ageing conditions, GDL water saturation and cell performance were revealed. Hereby, all cell operating conditions were tested several times to estimate the reproducibility of in-operando radiographic fuel cell measurements. Water films at the GDL-membrane and at the GDL-flow field interfaces were found and attributed to MPL cracks and large pores in the GDL structure. The combination of these cracks and pores are assumed to play a crucial role for blocked gas paths, leading to an undersupply with reactants and an increased humidification of the membrane. It is shown that water agglomerations directly impact the membrane resistance. We assume that the hydrophobicity of the fibers inside the GDL is more important for the cell performance than water agglomerations at the membrane-GDL interface. - Highlights: • Influence of ageing of gas diffusion layers on cell performance was investigated. • Cell performance decreased using artificially aged GDLs. • Performance decrease correlated to altered water distribution. • Reproducibility of water thickness measurements with synchrotron imaging.

  3. Redesigned Gas Mass Flow Sensors for Space Shuttle Pressure Control System and Fuel Cell System

    Science.gov (United States)

    1996-01-01

    A program was conducted to determine if a state of the art micro-machined silicon solid state flow sensor could be used to replace the existing space shuttle orbiter flow sensors. The rather aggressive goal was to obtain a new sensor which would also be a multi-gas sensor and operate over a much wider flow range and with a higher degree of accuracy than the existing sensors. Two types of sensors were tested. The first type was a venturi throat design and the second was a bypass design. The accuracy of venturi design was found to be marginally acceptable. The bypass sensor was much better although it still did not fully reach the accuracy goal. Two main problems were identified which would require further work.

  4. Design and manufacturing concrete cells for shielding and storing radioactive semi liquid waste (resin) from MPR-GAS

    International Nuclear Information System (INIS)

    Pudjijanto-MS; Bahdir-Johan

    2003-01-01

    Semi liquid or quasi solid waste on Multipurpose Reactor G.A. Siwabessy (MPR-GAS) produced from operating resin rinsing systems and resin disposal systems during changes insert trap resin. Volume of the disposal resin waste in the filter mixed-bed per operation rinsing period are approx. 1.00 m 3 (in the Primary Cooling Water Treatment System) with activity ∼ 18.6 Ci/m 3 (0.688 TBq/m 3 ), 0.50 m 3 (in the Radioisotope Storage Pool Water Treatment System) with activity approx ∼ 0.162 Ci/m 3 (5.99 x 10 3 MBq/m 3 ) and 0.50 m 3 (in the Interim Spent Fuel Storage Pool Water Treatment System) with activity ∼ 0.162 Ci/m 3 (5.99 x 10 3 MBq/m 3 ) respectively. On the discharging and unloading, the gross radioactivity concentration of the resin waste loaded in the disposal resin waste tank are approx. 10 Ci/m 3 (0.37 TBq/m 3 ). After 6 months delayed, this activity is still 0.32 Ci/m 3 (11.84 GBq/m 3 ). Based on this data, some concrete cells to storage resin waste as semi liquid or quasi solid waste produced continuously by MPR-GAS installation has been designed and manufactured eternally

  5. Investigation of liquid water in gas diffusion layers of polymer electrolyte fuel cells using X-ray tomographic microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Flueckiger, Reto [Electrochemistry Laboratory, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Marone, Federica [Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Stampanoni, Marco [Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Institute for Biomedical Engineering, University and ETH Zurich, Gloriastrasse 35, CH-8092 Zurich (Switzerland); Wokaun, Alexander [Electrochemistry Laboratory, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Buechi, Felix N., E-mail: felix.buechi@psi.c [Electrochemistry Laboratory, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland)

    2011-02-01

    In polymer electrolyte fuel cells (PEFCs), condensation of water within the pore network of the gas diffusion layers (GDL) can influence the gas transport properties and thus reduce the electrochemical conversion rates. The use of X-ray tomographic microscopy (XTM), which allows for a resolution in the order of one micrometer is investigated for studying ex situ the local saturation in GDL's. The strength of XTM is the high spatial resolution with simultaneous contrast for water and carbon, allowing for non-destructive 3D-imaging of the solid and the contained water. The application of this method for imaging the ex situ water intrusion into the porous network of GDLs is explored using absorption and phase contrast methods. It is shown that the inhomogeneous filling behavior of GDL materials can indeed be visualized with sufficient resolution. For Toray paper TGP-H-060 the local saturation was measured as function of the water pressure. The results, evaluated in 1D, 2D and 3D show a liquid water retention effect at the denser layers near the surface. A comparison with established capillary pressure functions is presented. Altogether, the results show the potential of the XTM-method as a tool for studying the liquid water behavior in PEFC on a microscopic scale.

  6. Investigation of liquid water in gas diffusion layers of polymer electrolyte fuel cells using X-ray tomographic microscopy

    International Nuclear Information System (INIS)

    Flueckiger, Reto; Marone, Federica; Stampanoni, Marco; Wokaun, Alexander; Buechi, Felix N.

    2011-01-01

    In polymer electrolyte fuel cells (PEFCs), condensation of water within the pore network of the gas diffusion layers (GDL) can influence the gas transport properties and thus reduce the electrochemical conversion rates. The use of X-ray tomographic microscopy (XTM), which allows for a resolution in the order of one micrometer is investigated for studying ex situ the local saturation in GDL's. The strength of XTM is the high spatial resolution with simultaneous contrast for water and carbon, allowing for non-destructive 3D-imaging of the solid and the contained water. The application of this method for imaging the ex situ water intrusion into the porous network of GDLs is explored using absorption and phase contrast methods. It is shown that the inhomogeneous filling behavior of GDL materials can indeed be visualized with sufficient resolution. For Toray paper TGP-H-060 the local saturation was measured as function of the water pressure. The results, evaluated in 1D, 2D and 3D show a liquid water retention effect at the denser layers near the surface. A comparison with established capillary pressure functions is presented. Altogether, the results show the potential of the XTM-method as a tool for studying the liquid water behavior in PEFC on a microscopic scale.

  7. SIMULATION OF POROSITY AND PTFE CONTENT IN GAS DIFFUSION LAYER ON PROTON EXCHANGE MEMBRANE FUEL CELL PERFORMANCE

    Directory of Open Access Journals (Sweden)

    NUR H. MASLAN

    2016-01-01

    Full Text Available Numerous research and development activities have been conducted to optimize the operating parameters of a proton exchange membrane fuel cell (PEMFC by experiments and simulations. This study explains the development of a 3D model by using ANSYS FLUENT 14.5 to determine the optimum PEMFC parameters, namely, porosity and polytetrafluoroethylene (PTFE content, in the gas diffusion layer (GDL. A 3D model was developed to analyze the properties and effects of GDL. Simulation results showed that the increase in GDL porosity significantly improved the performance of PEMFC in generating electrical power. However, the performance of PEMFC decreased with increasing PTFE content in GDL. Thus, the PTFE content in the GDL must be optimized and the optimum PTFE content should be 5 wt%. The model developed in this simulation showed good capability in simulating the PEMFC parameters to assist the development process of PEMFC design.

  8. A comprehensive review of microbial electrolysis cells (MEC reactor designs and configurations for sustainable hydrogen gas production

    Directory of Open Access Journals (Sweden)

    Abudukeremu Kadier

    2016-03-01

    Full Text Available Hydrogen gas has tremendous potential as an environmentally acceptable energy carrier for vehicles. A cutting edge technology called a microbial electrolysis cell (MEC can achieve sustainable and clean hydrogen production from a wide range of renewable biomass and wastewaters. Enhancing the hydrogen production rate and lowering the energy input are the main challenges of MEC technology. MEC reactor design is one of the crucial factors which directly influence on hydrogen and current production rate in MECs. The rector design is also a key factor to up-scaling. Traditional MEC designs incorporated membranes, but it was recently shown that membrane-free designs can lead to both high hydrogen recoveries and production rates. Since then multiple studies have developed reactors that operate without membranes. This review provides a brief overview of recent advances in research on scalable MEC reactor design and configurations.

  9. Corrosion characterisation of laser beam and tungsten inert gas weldment of nickel base alloys: Micro-cell technique

    International Nuclear Information System (INIS)

    Abraham, Geogy J.; Kain, V.; Dey, G.K.; Raja, V.S.

    2015-01-01

    Highlights: • Grain matrix showed better corrosion resistance than grain boundary. • Microcell studies showed distinct corrosion behaviour of individual regions of weldment. • TIG welding resulted in increased stable anodic current density on weld fusion zone. • LB welding resulted in high stable anodic current density for heat affected zone. - Abstract: The electrochemical studies using micro-cell technique gave new understanding of electrochemical behaviour of nickel base alloys in solution annealed and welded conditions. The welding simulated regions depicted varied micro structural features. In case of tungsten inert gas (TIG) weldments, the weld fusion zone (WFZ) showed least corrosion resistance among all other regions. For laser beam (LB) weldments it was the heat-affected zone (HAZ) that showed comparatively high stable anodic current density. The high heat input of TIG welding resulted in slower heat dissipation hence increased carbide precipitation and segregation in WFZ resulting in high stable anodic current density

  10. Enhanced nitrogen removal in single-chamber microbial fuel cells with increased gas diffusion areas

    KAUST Repository

    Yan, Hengjing; Regan, John M.

    2012-01-01

    significantly increased the ammonia and COD removal rates (by up to 115% and 39%), ammonia removal efficiency (by up to 134%), the cell voltage and cathode potentials, and the power densities (by a factor of approximately 2). When the COD/N ratio was lowered

  11. Membrane separation principle used for gas drying processes in fuel cells and life support systems

    International Nuclear Information System (INIS)

    Nigsch, H.A.; Fleck, W.U.

    1991-07-01

    Different membrane separation principles as applied to fuel cell powerplants and ECLSS are described. A new separator type that enables smaller weight and geometries and requires less energy than conventional mechanical separator techniques for space applications is presented. Module optimization and investigations concerning ECLSS applications are discussed. 5 refs

  12. High Temperature Alkaline Electrolysis Cells with Metal Foam Based Gas Diffusion Electrodes

    DEFF Research Database (Denmark)

    Chatzichristodoulou, Christodoulos; Allebrod, Frank; Mogensen, Mogens Bjerg

    2016-01-01

    Alkaline electrolysis cells operating at 250°C and 40 bar are able to convert electrical energy into hydrogen at very high efficiencies and power densities. In the present work we demonstrate the application of a PTFE hydrophobic network and Ag nanowires as oxygen evolution electrocatalyst...

  13. Thermoeconomic Modeling and Parametric Study of Hybrid Solid Oxide Fuel Cell â Gas Turbine â Steam Turbine Power Plants Ranging from 1.5 MWe to 10 MWe

    OpenAIRE

    Arsalis, Alexandros

    2007-01-01

    Detailed thermodynamic, kinetic, geometric, and cost models are developed, implemented, and validated for the synthesis/design and operational analysis of hybrid solid oxide fuel cell (SOFC) â gas turbine (GT) â steam turbine (ST) systems ranging in size from 1.5 MWe to 10 MWe. The fuel cell model used in this thesis is based on a tubular Siemens-Westinghouse-type SOFC, which is integrated with a gas turbine and a heat recovery steam generator (HRSG) integrated in turn with a steam turbi...

  14. Full and part load exergetic analysis of a hybrid micro gas turbine fuel cell system based on existing components

    International Nuclear Information System (INIS)

    Bakalis, Diamantis P.; Stamatis, Anastassios G.

    2012-01-01

    Highlights: ► Hybrid SOFC/GT system based on existing components. ► Exergy analysis using AspenPlus™ software. ► Greenhouse gases emission is significantly affected by SOFC stack temperature. ► Comparison with a conventional GT of similar power. ► SOFC/GT is almost twice efficient in terms of second low efficiency and CO 2 emission. - Abstract: The paper deals with the examination of a hybrid system consisting of a pre-commercially available high temperature solid oxide fuel cell and an existing recuperated microturbine. The irreversibilities and thermodynamic inefficiencies of the system are evaluated after examining the full and partial load exergetic performance and estimating the amount of exergy destruction and the efficiency of each hybrid system component. At full load operation the system achieves an exergetic efficiency of 59.8%, which increases during the partial load operation, as a variable speed control method is utilized. Furthermore, the effects of the various performance parameters such as fuel cell stack temperature and fuel utilization factor are assessed. The results showed that the components in which chemical reactions occur have the higher exergy destruction rates. The exergetic performance of the system is affected significantly by the stack temperature. Based on the exergetic analysis, suggestions are given for reducing the overall system irreversibility. Finally, the environmental impact of the operation of the hybrid system is evaluated and compared with a similarly rated conventional gas turbine plant. From the comparison it is apparent that the hybrid system obtains nearly double exergetic efficiency and about half the amount of greenhouse gas emissions compared with the conventional plant.

  15. Lifecycle cost assessment and carbon dioxide emissions of diesel, natural gas, hybrid electric, fuel cell hybrid and electric transit buses

    International Nuclear Information System (INIS)

    Lajunen, Antti; Lipman, Timothy

    2016-01-01

    This paper evaluates the lifecycle costs and carbon dioxide emissions of different types of city buses. The simulation models of the different powertrains were developed in the Autonomie vehicle simulation software. The carbon dioxide emissions were calculated both for the bus operation and for the fuel and energy pathways from well to tank. Two different operating environment case scenarios were used for the primary energy sources, which were Finland and California (USA). The fuel and energy pathways were selected appropriately in relation to the operating environment. The lifecycle costs take into account the purchase, operating, maintenance, and possible carbon emission costs. Based on the simulation results, the energy efficiency of city buses can be significantly improved by the alternative powertrain technologies. Hybrid buses have moderately lower carbon dioxide emissions during the service life than diesel buses whereas fully-electric buses have potential to significantly reduce carbon dioxide emissions, by up to 75%. The lifecycle cost analysis indicates that diesel hybrid buses are already competitive with diesel and natural gas buses. The high costs of fuel cell and battery systems are the major challenges for the fuel cell hybrid buses in order to reduce lifecycle costs to more competitive levels. - Highlights: • Alternative powertrains can significantly improve energy efficiency of transit buses. • Operating environment has an important impact on the lifecycle costs of buses. • Diesel hybrid buses are already cost effective solution for public transportation. • The cost of fuel cell technology is the major challenge for fuel cell hybrid buses. • Fully-electric buses have potential to significantly reduce carbon dioxide emissions.

  16. Analysis of Gas Leakage and Current Loss of Solid Oxide Fuel Cells by Screen Printing

    DEFF Research Database (Denmark)

    Jia, Chuan; Han, Minfang; Chen, Ming

    2017-01-01

    operating life and lead to performance degradation. The planar anode-supported Ni-YSZ|YSZ|LSCF SOFC was chosen as the research object, with the cell size of 12cm×12cm and the effective area of 100cm2, and the holder is made of 99% purity of Al2O3 ceramic material, in order to eliminate the influence of Cr...

  17. Case report 496: Intraosseous gas in Proteus mirabilis osteomyelitis complicating bone infarcts in sickle cell disease

    International Nuclear Information System (INIS)

    Marx, A.C.; Hartshorne, M.F.; Stull, M.A.; Truwit, C.L.

    1988-01-01

    Plain film radiographs showed dramatic changes of this rare complication of sickle cell disease in an adult patient, eventually resulting in bilateral amputations of the lower extremities. Cross table radiographs of the knees showed the air-fluid levels without soft tissue swelling or periosteal reaction. The balance of the studies performed confirmed and refined the initial impression that infarction and infection had occurred within the medullary spaces of four long bones. The offending organism was Proteus mirabilis. (orig.)

  18. Case report 496: Intraosseous gas in Proteus mirabilis osteomyelitis complicating bone infarcts in sickle cell disease

    Energy Technology Data Exchange (ETDEWEB)

    Marx, A.C.; Hartshorne, M.F.; Stull, M.A.; Truwit, C.L.

    1988-10-01

    Plain film radiographs showed dramatic changes of this rare complication of sickle cell disease in an adult patient, eventually resulting in bilateral amputations of the lower extremities. Cross table radiographs of the knees showed the air-fluid levels without soft tissue swelling or periosteal reaction. The balance of the studies performed confirmed and refined the initial impression that infarction and infection had occurred within the medullary spaces of four long bones. The offending organism was Proteus mirabilis.

  19. Design considerations for teleoperation systems operating in gas-tight argon cells

    Directory of Open Access Journals (Sweden)

    Seungnam Yu

    2017-12-01

    Full Text Available In the nuclear industry, mechanical engineers spend a significant portion of their time designing equipment such as manipulators, bogies, mechanical grippers, and so on. Some customized designs can be considered as standard mechanical equipment in this area, although it is not unusual to find that an existing design cannot simply be copied from one project to another. Varied performance requirements can dictate that redesign, often quite extensive redesign, is required. However, if something similar has been done before, engineers could use that as a starting point for the new project. In this regard, this study presents several guidelines inspired by previous design knowledge for similar development cases. Moreover, this study presents more detailed suggestions such as design guidelines for an argon-based hot cell atmosphere and design experience for a large-scale practical hot cell facility. Design considerations and case studies dealt with in this study are dedicated to teleoperation manipulators that are used at a large-scale argon cell facility for pyroprocess integrated inactive demonstration (PRIDE, at the Korea Atomic Energy Research Institute. In particular, for case studies to support the suggested recommendations, a fabricated telemanipulator system for PRIDE is introduced, and several kinds of experimental results associated with it are presented.

  20. Effects of biomass-generated producer gas constituents on cell growth, product distribution and hydrogenase activity of Clostridium carboxidivorans P7{sup T}

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Asma [Oklahoma State University, Stillwater, OK (United States). School of Chemical Engineering; Cateni, Bruno G.; Huhnke, Raymond L. [Oklahoma State University, Stillwater, OK (United States). Department of Biosystems and Agricultural Engineering; Lewis, Randy S. [Brigham Young University, Provo, UT (United States). Chemical Engineering Department

    2006-07-15

    In our previous work, we demonstrated that biomass-generated producer gas can be converted to ethanol and acetic acid using a microbial catalyst Clostridium carboxidivorans P7{sup T}. Results showed that the producer gas (1) induced cell dormancy, (2) inhibited H{sub 2} consumption, and (3) affected the acetic acid/ethanol product distribution. Results of this work showed that tars were the likely cause of cell dormancy and product redistribution and that the addition of a 0.025{mu}m filter in the gas cleanup negated the effects of tars. C. carboxidivorans P7{sup T} can adapt to the tars (i.e. grow) only after prolonged exposure. Nitric oxide, present in the producer gas at 150ppm, is an inhibitor of the hydrogenase enzyme involved in H{sub 2} consumption. We conclude that significant conditioning of the producer gas will be required for the successful coupling of biomass-generated producer gas with fermentation to produce ethanol and acetic acid. (author)

  1. Effects of biomass-generated producer gas constituents on cell growth, product distribution and hydrogenase activity of Clostridium carboxidivorans P7T

    International Nuclear Information System (INIS)

    Ahmed, Asma; Cateni, Bruno G.; Huhnke, Raymond L.; Lewis, Randy S.

    2006-01-01

    In our previous work, we demonstrated that biomass-generated producer gas can be converted to ethanol and acetic acid using a microbial catalyst Clostridium carboxidivorans P7 T . Results showed that the producer gas (1) induced cell dormancy, (2) inhibited H 2 consumption, and (3) affected the acetic acid/ethanol product distribution. Results of this work showed that tars were the likely cause of cell dormancy and product redistribution and that the addition of a 0.025μm filter in the gas cleanup negated the effects of tars. C. carboxidivorans P7 T can adapt to the tars (i.e. grow) only after prolonged exposure. Nitric oxide, present in the producer gas at 150ppm, is an inhibitor of the hydrogenase enzyme involved in H 2 consumption. We conclude that significant conditioning of the producer gas will be required for the successful coupling of biomass-generated producer gas with fermentation to produce ethanol and acetic acid. (author)

  2. A flexible gas flow reaction cell for in situ x-ray absorption spectroscopy studies

    Energy Technology Data Exchange (ETDEWEB)

    Kroner, Anna B., E-mail: anna.kroner@diamond.ac.uk; Gilbert, Martin; Duller, Graham; Cahill, Leo; Leicester, Peter; Woolliscroft, Richard; Shotton, Elizabeth J. [Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Chilton, Oxfordshire, OX110DE (United Kingdom); Mohammed, Khaled M. H. [UK Catalysis Hub, Research Complex at Harwell, Rutherford Appleton Laboratory, Chilton, Oxfordshire, OX110FA (United Kingdom); School of Chemistry, University of Southampton, Southampton, SO17 1BJ (United Kingdom)

    2016-07-27

    A capillary-based sample environment with hot air blower and integrated gas system was developed at Diamond to conduct X-ray absorption spectroscopy (XAS) studies of materials under time-resolved, in situ conditions. The use of a hot air blower, operating in the temperature range of 298-1173 K, allows introduction of other techniques e.g. X-ray diffraction (XRD), Raman spectroscopy for combined techniques studies. The flexibility to use either quartz or Kapton capillaries allows users to perform XAS measurement at energies as low as 5600 eV. To demonstrate performance, time-resolved, in situ XAS results of Rh catalysts during the process of activation (Rh K-edge, Ce L{sub 3}-edge and Cr K-edge) and the study of mixed oxide membrane (La{sub 0.6}Sr{sub 0.4}Co{sub 0.2}Fe{sub 0.8}O{sub 3−δ}) under various partial oxygen pressure conditions are described.

  3. Bulk and contact resistances of gas diffusion layers in proton exchange membrane fuel cells

    Science.gov (United States)

    Ye, Donghao; Gauthier, Eric; Benziger, Jay B.; Pan, Mu

    2014-06-01

    A multi-electrode probe is employed to distinguish the bulk and contact resistances of the catalyst layer (CL) and the gas diffusion layer (GDL) with the bipolar plate (BPP). Resistances are compared for Vulcan carbon catalyst layers (CL), carbon paper and carbon cloth GDL materials, and GDLs with microporous layers (MPL). The Vulcan carbon catalyst layer bulk resistance is 100 times greater than the bulk resistance of carbon paper GDL (Toray TG-H-120). Carbon cloth (CCWP) has bulk and contact resistances twice those of carbon paper. Compression of the GDL decreases the GDL contact resistance, but has little effect on the bulk resistance. Treatment of the GDL with polytetrafluoroethylene (PTFE) increases the contact resistance, but has little effect on the bulk resistance. A microporous layer (MPL) added to the GDL decreases the contact resistance, but has little effect on the bulk resistance. An equivalent circuit model shows that for channels less than 1 mm wide the contact resistance is the major source of electronic resistance and is about 10% of the total ohmic resistance associated with the membrane electrode assembly.

  4. ZTEK`s ultra-high efficiency fuel cell/gas turbine system for distributed generation

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, M.; Nathanson, D. [Ztek Corp., Waltham, MA (United States); Bradshaw, D.T. [Tennessee Valley Authority, Chattanooga, TN (United States)] [and others

    1996-12-31

    Ztek`s Planar Solid Oxide Fuel Cell (SOFC) system has exceptional potential for utility electric power generation because of: simplicity of components construction, capability for low cost manufacturing, efficient recovery of very high quality by-product heat (up to 1000{degrees}C), and system integration simplicity. Utility applications of the Solid Oxide Fuel Cell are varied and include distributed generation units (sub-MW to 30MW capacity), repowering existing power plants (i.e. 30MW to 100MW), and multi-megawatt central power plants. A TVA/EPRI collaboration program involved functional testing of the advanced solid oxide fuel cell stacks and design scale-up for distributed power generation applications. The emphasis is on the engineering design of the utility modules which will be the building blocks for up to megawatt scale power plants. The program has two distinctive subprograms: Verification test on a 1 kW stack and 25kW module for utility demonstration. A 1 kW Planar SOFC stack was successfully operated for 15,000 hours as of December, 1995. Ztek began work on a 25kW SOFC Power System for TVA, which plans to install the 25kW SOFC at a host site for demonstration in 1997. The 25kW module is Ztek`s intended building block for the commercial use of the Planar SOFC. Systems of up to megawatt capacity can be obtained by packaging the modules in 2-dimensional or 3-dimensional arrays.

  5. Exergy Analysis of an Intermediate Temperature Solid Oxide Fuel Cell-Gas Turbine Hybrid System Fed with Ethanol

    Directory of Open Access Journals (Sweden)

    Fotini Tzorbatzoglou

    2012-10-01

    Full Text Available In the present work, an ethanol fed Solid Oxide Fuel Cell-Gas Turbine (SOFC-GT system has been parametrically analyzed in terms of exergy and compared with a single SOFC system. The solid oxide fuel cell was fed with hydrogen produced from ethanol steam reforming. The hydrogen utilization factor values were kept between 0.7 and 1. The SOFC’s Current-Volt performance was considered in the range of 0.1–3 A/cm2 at 0.9–0.3 V, respectively, and at the intermediate operating temperatures of 550 and 600 °C, respectively. The curves used represent experimental results obtained from the available bibliography. Results indicated that for low current density values the single SOFC system prevails over the SOFC-GT hybrid system in terms of exergy efficiency, while at higher current density values the latter is more efficient. It was found that as the value of the utilization factor increases the SOFC system becomes more efficient than the SOFC-GT system over a wider range of current density values. It was also revealed that at high current density values the increase of SOFC operation temperature leads in both cases to higher system efficiency values.

  6. Solid oxide fuel cell/gas turbine hybrid system analysis for high-altitude long-endurance unmanned aerial vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, P.; Brandon, N.P. [Department of Earth Science and Engineering, Imperial College London, London SW7 2AZ (United Kingdom); Brett, D.J.L. [The Centre for CO{sub 2} Technology, University College London, London WC1E 7JE (United Kingdom)

    2008-12-15

    High-altitude long-endurance (HALE) unmanned aerial vehicles (UAVs) are ideally suited to provide surveillance, remote sensing and communication relay capabilities for both military and civilian applications. HALE UAVs typically cruise at an altitude between 15 km and 20 km, travelling at low speed and circling specific areas of interest. The work reported aims to investigate alternative power system architectures that enable an efficiency increase and consequent fuel consumption reduction to realise a one-week endurance target. Specifically, the application of a solid oxide fuel cell combined with a gas turbine is considered; with different system configurations modelled with a view to maximising overall efficiency. It is found that modularising the fuel cell capacity into a number of discrete stacks such that the fuel is distributed in parallel and air is fed in series results in an increased system efficiency compared with a single-stack design. An overall system efficiency of 66.3% (LHV) when operating on hydrogen is predicted for a three-stack system. (author)

  7. Validity of two-phase polymer electrolyte membrane fuel cell models with respect to the gas diffusion layer

    Science.gov (United States)

    Ziegler, C.; Gerteisen, D.

    A dynamic two-phase model of a proton exchange membrane fuel cell with respect to the gas diffusion layer (GDL) is presented and compared with chronoamperometric experiments. Very good agreement between experiment and simulation is achieved for potential step voltammetry (PSV) and sine wave testing (SWT). Homogenized two-phase models can be categorized in unsaturated flow theory (UFT) and multiphase mixture (M 2) models. Both model approaches use the continuum hypothesis as fundamental assumption. Cyclic voltammetry experiments show that there is a deterministic and a stochastic liquid transport mode depending on the fraction of hydrophilic pores of the GDL. ESEM imaging is used to investigate the morphology of the liquid water accumulation in the pores of two different media (unteflonated Toray-TGP-H-090 and hydrophobic Freudenberg H2315 I3). The morphology of the liquid water accumulation are related with the cell behavior. The results show that UFT and M 2 two-phase models are a valid approach for diffusion media with large fraction of hydrophilic pores such as unteflonated Toray-TGP-H paper. However, the use of the homgenized UFT and M 2 models appears to be invalid for GDLs with large fraction of hydrophobic pores that corresponds to a high average contact angle of the GDL.

  8. Investigations of space charge effects in the cryogenic gas filled stopping cell for the FRS ion catcher

    Energy Technology Data Exchange (ETDEWEB)

    Heisse, Fabian [IKTP, TU Dresden (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung (Germany); Dickel, Timo; Plass, Wolfgang; Geissel, Hans; Scheidenberger, Christoph [II. Physikalisches Institut, JLU Giessen (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung (Germany); Reiter, Moritz Pascal; Rink, Ann-Kathrin [II. Physikalisches Institut, JLU Giessen (Germany); Zuber, Kai [IKTP, TU Dresden (Germany); Collaboration: FRS Ion Catcher-Collaboration

    2015-07-01

    At the FRS Ion Catcher experiment precision mass measurements of short lived projectile and fission fragments are performed. Therefore highly charged ions with relativistic energies need to be thermalized to kinetic energies of several eV. This process takes place in the cryogenic gas filled stopping cell (CSC). All stopping cells suffer at large ion rates under space charge effects, which lead to decreasing efficiencies and can also influence the extraction time. Thus the understanding of space charge effects is of greatest importance to make full use of the higher yields at future rare ion beam facilities like FAIR. For this purpose simulation with the software SIMION {sup registered} concerning space charge effects were done. In this presentation the calculated transport efficiency of the CSC for different intensities, electric fields and spill structures are discussed and compared with measured results. Furthermore an outlook and first results of the simulation for the new CSC for the Low-Energy Branch at FAIR are given.

  9. Sub-doppler spectroscopy based on the transit relaxation of atomic particles in a thin gas cell

    International Nuclear Information System (INIS)

    Azad, Izmailov

    2011-01-01

    This paper is the review of methods, achievements, and possibilities of the recently elaborated high-resolution laser spectroscopy based on sub-doppler absorption, fluorescence and polarization resonances (on centers of quantum transitions), which arise because of the specific optical selection of comparatively slow-speed atoms or molecules in a thin cell with a rarefied gas. It is considered two following mechanisms of such velocity selection of atomic particles connected with their flight durations between walls of the thin cell : 1) optical pumping of sublevels of the ground atomic term and 2) optical excitation of long-lived metastable quantum levels. Theoretical bases of elaborated spectroscopy methods are presented. In case of the optical pumping mechanism, experimental technique and results on the record of sub-doppler spectral structure of Cs and Rb atoms and on the frequency stabilization of diode lasers by given methods are described. Perspectives of further development and applications of this new direction of the high-resolution spectroscopy are discussed

  10. Electrochemical atomic layer deposition of Pt nanostructures on fuel cell gas diffusion layer

    CSIR Research Space (South Africa)

    Modibedi, M

    2010-12-01

    Full Text Available and test MEA?s performance in PEMFC. BIBLIOGRAPHY 1. Barbir F., (2005) PEM Fuel Cells: Theory and Practice, Elsevier Academic Press Oxford. 2. Yang T.-H., et al (2004) J. Power Sources 127 230. 3. Hirano S., Kim J. and Srinivasan S., (1997) Electrochim... stream_source_info Modibedi_2010.pdf.txt stream_content_type text/plain stream_size 5644 Content-Encoding ISO-8859-1 stream_name Modibedi_2010.pdf.txt Content-Type text/plain; charset=ISO-8859-1 RESULTS AND DISCUSSIONS...

  11. Evaluation of gasification and gas cleanup processes for use in molten carbonate fuel cell power plants. Final report. [Contains lists and evaluations of coal gasification and fuel gas desulfurization processes

    Energy Technology Data Exchange (ETDEWEB)

    Jablonski, G.; Hamm, J.R.; Alvin, M.A.; Wenglarz, R.A.; Patel, P.

    1982-01-01

    This report satisfies the requirements for DOE Contract AC21-81MC16220 to: List coal gasifiers and gas cleanup systems suitable for supplying fuel to molten carbonate fuel cells (MCFC) in industrial and utility power plants; extensively characterize those coal gas cleanup systems rejected by DOE's MCFC contractors for their power plant systems by virtue of the resources required for those systems to be commercially developed; develop an analytical model to predict MCFC tolerance for particulates on the anode (fuel gas) side of the MCFC; develop an analytical model to predict MCFC anode side tolerance for chemical species, including sulfides, halogens, and trace heavy metals; choose from the candidate gasifier/cleanup systems those most suitable for MCFC-based power plants; choose a reference wet cleanup system; provide parametric analyses of the coal gasifiers and gas cleanup systems when integrated into a power plant incorporating MCFC units with suitable gas expansion turbines, steam turbines, heat exchangers, and heat recovery steam generators, using the Westinghouse proprietary AHEAD computer model; provide efficiency, investment, cost of electricity, operability, and environmental effect rankings of the system; and provide a final report incorporating the results of all of the above tasks. Section 7 of this final report provides general conclusions.

  12. A numerical study of the gas-liquid, two-phase flow maldistribution in the anode of a high pressure PEM water electrolysis cell

    DEFF Research Database (Denmark)

    Olesen, Anders Christian; Rømer, Carsten; Kær, Søren Knudsen

    2016-01-01

    In this work, the use of a circular-planar, interdigitated flow field for the anode of a high pressure proton exchange membrane (PEM) water electrolysis cell is investigated in a numerical study. While PEM fuel cells have separated flow fields for reactant transport and coolant, it is possible...... causes maldistribution, if land areas of equal width are applied. Moreover, below a water stoichiometry of 350, and at a current density of 1 A/cm2, flow and temperature maldistribution is adversely affected by the presence of the gas phase; particularly gas hold-up near outlet channels can cause......-phase flow model for establishing the effect of geometry and a two-phase flow model for studying the effect of dispersed gas bubbles. Both models account for turbulence and heat transport. By means of the developed models, it is elucidated that the circular-planar shape of the interdigitated flow field...

  13. Produksi Gas hidrogen dari Limbah Alumunium dan Uji Daya Listrik dengan Fuel Cell

    Directory of Open Access Journals (Sweden)

    Yusraini DIS

    2017-03-01

    Full Text Available Teknologi Fuel Cell adalah teknologi masa depan yang ramah lingkungan. Bahan baku untuk fuel cell adalah hidrogen. Produksi hidrogen dari limbah alumunium dan storage telah dilakukan. Penelitian ini bertujuan untuk memanfaatkan limbah alumunium (alumunium foil dan kaleng minuman yang direaksikan dengan larutan beralkalin untuk menghasilkan hidrogen. Hidrogen yang dihasilkan sebanding dengan tekanan yang terukur yang diukur dengan CASSY LAB Version 1.41. Hasilnya adalah: a. Semakin tinggi konsentrasi NaOH (5 %, 10 % dan 15 % semakin cepat reaksi produksi hidrogen berlangsung. b. Jumlah limbah alumunium yang berbeda (0,01 g, 0,05 g dan 0,10 g kurang berpengaruh terhadap waktu reaksi jika konsentrasi NaOHnya sama. c. Temperatur yang dihasilkan berkisar antara 27 oC - 33,7 oC, semakin banyak jumlah alumunium yang direaksikan semakin tinggi temperatur yang dihasilkan. d. Daya listrik yang dihasilkan dari 0,10 gram alumunium foil adalah sebesar 45-51 watt dengan daya rata-rata 0,08 watt per detik. e. Daya listrik yang dihasilkan dengan kaleng Coca Cola adalah sebesar 12,13 watt dengan daya rata-rata 0,009 watt per detik.

  14. TREX1 deficiency triggers cell-autonomous immunity in a cGAS-dependent manner.

    Science.gov (United States)

    Ablasser, Andrea; Hemmerling, Inga; Schmid-Burgk, Jonathan L; Behrendt, Rayk; Roers, Axel; Hornung, Veit

    2014-06-15

    Cytosolic detection of DNA is crucial for the initiation of antiviral immunity but can also cause autoimmunity in the context of endogenous nucleic acids being sensed. Mutations in the human 3' repair exonuclease 1 (TREX1) have been linked to the type I IFN-associated autoimmune disease Aicardi-Goutières syndrome. The exact mechanisms driving unabated type I IFN responses in the absence of TREX1 are only partly understood, but it appears likely that accumulation of endogenous DNA species triggers a cell-autonomous immune response by activating a cytosolic DNA receptor. In this article, we demonstrate that knocking out the DNA sensor cyclic GMP-AMP synthase completely abrogates spontaneous induction of IFN-stimulated genes in TREX1-deficient cells. These findings indicate a key role of cyclic GMP-AMP synthase for the initiation of self-DNA-induced autoimmune disorders, thus providing important implications for novel therapeutic approaches. Copyright © 2014 by The American Association of Immunologists, Inc.

  15. Pore-Network Modeling of Water and Vapor Transport in the Micro Porous Layer and Gas Diffusion Layer of a Polymer Electrolyte Fuel Cell

    NARCIS (Netherlands)

    Qin, C.; Hassanizadeh, S.M.; van Oosterhout, L.M.

    2016-01-01

    In the cathode side of a polymer electrolyte fuel cell (PEFC), a micro porous layer (MPL) added between the catalyst layer (CL) and the gas diffusion layer (GDL) plays an important role in water management. In this work, by using both quasi-static and dynamic pore-network models, water and vapor

  16. Design of adiabatic fixed-bed reactors for the partial oxidation of methane to synthesis gas. Application to production of methanol and hydrogen-for-fuel-cells

    NARCIS (Netherlands)

    Smet, de C.R.H.; Croon, de M.H.J.M.; Berger, R.J.; Marin, G.B.M.M.; Schouten, J.C.

    2001-01-01

    Adiabatic fixed-bed reactors for the catalytic partial oxidn. (CPO) of methane to synthesis gas were designed at conditions suitable for the prodn. of methanol and hydrogen-for-fuel-cells. A steady-state, one-dimensional heterogeneous reactor model was applied in the simulations. Intra-particle

  17. Direct synthesis of Pt-free catalyst on gas diffusion layer of fuel cell and usage of high boiling point fuels for efficient utilization of waste heat

    International Nuclear Information System (INIS)

    Nandan, Ravi; Goswami, Gopal Krishna; Nanda, Karuna Kar

    2017-01-01

    Graphical abstract: Direct-grown boron-doped carbon nanotubes on gas-diffusion layer as efficient Pt-free cathode catalyst for alcohol fuel cells, high boiling point fuels used to obtain hot fuels for the enhancement of cell performance that paves the way for the utilization of waste heat. Display Omitted -- Highlights: •One-step direct synthesis of boron-doped carbon nanotubes (BCNTs) on gas diffusion layer (GDL). •Home built fuel-cell testing using BCNTs on GDL as Pt-free cathode catalyst. •BCNTs exhibit concentration dependent oxygen reduction reaction and the cell performance. •Effective utilization of waste heat to raise the fuel temperature. •Fuel selectivity to raise the fuel temperature and the overall performance of the fuel cells. -- Abstract: Gas diffusion layers (GDL) and electrocatalysts are integral parts of fuel cells. It is, however, a challenging task to grow Pt-free robust electrocatalyst directly on GDL for oxygen reduction reaction (ORR) – a key reaction in fuel cells. Here, we demonstrate that boron-doped carbon nanotubes (BCNTs) grown directly on gas-diffusion layer (which avoid the need of ionomer solution used for catalyst loading) can be used as efficient Pt-free catalyst in alcohol fuel cells. Increase in boron concentration improves the electrochemical ORR activity in terms of onset and ORR peak positions, half-wave potentials and diffusion-limited current density that ensure the optimization of the device performance. The preferential 4e − pathway, excellent cell performance, superior tolerance to fuel crossover and long-term stability makes directly grown BCNTs as an efficient Pt-free cathode catalyst for cost-effective fuel cells. The maximum power density of the fuel cell is found to increase monotonically with boron concentration. In addition to the application of BCNTs in fuel cell, we have introduced the concept of hot fuels so that waste heat can effectively be used and external power sources can be avoided. The fuel

  18. Preliminary analysis of compound systems based on high temperature fuel cell, gas turbine and Organic Rankine Cycle

    Science.gov (United States)

    Sánchez, D.; Muñoz de Escalona, J. M.; Monje, B.; Chacartegui, R.; Sánchez, T.

    This article presents a novel proposal for complex hybrid systems comprising high temperature fuel cells and thermal engines. In this case, the system is composed by a molten carbonate fuel cell with cascaded hot air turbine and Organic Rankine Cycle (ORC), a layout that is based on subsequent waste heat recovery for additional power production. The work will credit that it is possible to achieve 60% efficiency even if the fuel cell operates at atmospheric pressure. The first part of the analysis focuses on selecting the working fluid of the Organic Rankine Cycle. After a thermodynamic optimisation, toluene turns out to be the most efficient fluid in terms of cycle performance. However, it is also detected that the performance of the heat recovery vapour generator is equally important, what makes R245fa be the most interesting fluid due to its balanced thermal and HRVG efficiencies that yield the highest global bottoming cycle efficiency. When this fluid is employed in the compound system, conservative operating conditions permit achieving 60% global system efficiency, therefore accomplishing the initial objective set up in the work. A simultaneous optimisation of gas turbine (pressure ratio) and ORC (live vapour pressure) is then presented, to check if the previous results are improved or if the fluid of choice must be replaced. Eventually, even if system performance improves for some fluids, it is concluded that (i) R245fa is the most efficient fluid and (ii) the operating conditions considered in the previous analysis are still valid. The work concludes with an assessment about safety-related aspects of using hydrocarbons in the system. Flammability is studied, showing that R245fa is the most interesting fluid also in this regard due to its inert behaviour, as opposed to the other fluids under consideration all of which are highly flammable.

  19. Effects of upgrading systems on energy conversion efficiency of a gasifier - fuel cell - gas turbine power plant

    International Nuclear Information System (INIS)

    Pedrazzi, Simone; Allesina, Giulio; Tartarini, Paolo

    2016-01-01

    Highlights: • An advanced gasifier-SOFC-MGT system is modeled. • An overall electrical efficiency of 32.81% is reached. • Influence of all the sub-system modeled on the power plant efficiency is discussed. • Compression storage of syngas is taken into account. - Abstract: This work focuses on a DG-SOFC-MGT (downdraft gasifier - solid oxide fuel cell - micro gas turbine) power plant for electrical energy production and investigates two possible performance-upgrading systems: polyphenylene oxide (PPO) membrane and zeolite filters. The first is used to produce oxygen-enriched air used in the reactor, while the latter separates the CO_2 content from the syngas. In order to prevent power plant shutdowns during the gasifier reactor scheduled maintenance, the system is equipped with a gas storage tank. The generation unit consists of a SOFC-MGT system characterized by higher electrical efficiency when compared to conventional power production technology (IC engines, ORC and EFGT). Poplar wood chips with 10% of total moisture are used as feedstock. Four different combinations with and without PPO and zeolite filtrations are simulated and discussed. One-year energy and power simulation were used as basis for comparison between all the cases analyzed. The modeling of the gasification reactions gives results consistent with literature about oxygen-enriched processes. Results showed that the highest electrical efficiency obtained is 32.81%. This value is reached by the power plant equipped only with PPO membrane filtration. Contrary to the PPO filtering, zeolite filtration does not increase the SOFC-MGT unit performance while it affects the energy balance with high auxiliary electrical consumption. This solution can be considered valuable only for future work coupling a CO_2 sequestration system to the power plant.

  20. Experimental energetic analysis of gas natural-powered fuel cell cogeneration plant; Analise energetica experimental de uma planta de co-geracao com celulas a combustivel e gas natural

    Energy Technology Data Exchange (ETDEWEB)

    Furtado, Jose G.M.; Lopes, Francisco C.; Silva Junior, Fernando R.; Soares, Guilherme F.W.; Serra, Eduardo T. [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil)

    2008-07-01

    Power systems based on fuel cells have been considered for residential and commercial applications in energy Distributed Generation (DG) market as these systems can minimize their acquisition, installation and operation high costs. In this work we present an experimental analysis of a power generation system formed by a 5 kW proton exchange membrane fuel cell unit and a natural gas reformer (fuel processor) for hydrogen production, of the CEPEL's Fuel Cell Laboratory. It was determined the electrical performance of the cogeneration system in function of the design and operational power plant parameters. Additionally, it was verified the influence of the activation conditions of the fuel cell electrocatalytic system on the system performance. It also appeared that the use of hydrogen produced from the natural gas catalytic reforming provided the system operation in excellent electrothermal stability conditions resulting in increase of the energy conversion efficiency and of the economy of the cogeneration power plant. The maximum electrical efficiency achieved was around 38% and in all power range unit operated with average potential per single fuel cell higher than 0.60 V. (author)

  1. Energetic-economical analysis of a stationary for energy generation with fuel cells and natural gas reforming; Analise energetico-economica de um sistema estacionario de geracao de energia com celulas a combustivel e reforma de gas natural

    Energy Technology Data Exchange (ETDEWEB)

    Furtado, Jose Geraldo de Melo; Silva Junior, Fernando Rodrigues; Silva, Cristiane Abrantes da; Soares, Guilherme Fleury Wanderley; Lopes, Francisco da Costa; Serra, Eduardo Torres [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil)]. E-mail: furtado@cepel.br; Codeceira Neto, Alcides [Companhia HidroEletrica do Sao Francisco (CHESF), Recife, PE (Brazil)

    2008-07-01

    Power systems based on fuel cells have been considered for residential and commercial applications in energy Distributed Generation (DG) market as these systems can minimize their acquisition, installation and operation high costs. In this work we present an experimental analysis of a power generation system formed by a 5 kW proton exchange membrane fuel cell unit and a natural gas reformer (fuel processor) for hydrogen production, of the CEPEL's Fuel Cell Laboratory. It was determined the electrical performance of the cogeneration system in function of the design and operational power plant parameters. Additionally, it was verified the influence of the activation conditions of the fuel cell electrocatalytic system on the system performance. It also appeared that the use of hydrogen produced from the natural gas catalytic reforming provided the system operation in excellent electrothermal stability conditions resulting in increase of the energy conversion efficiency and of the economicity of the cogeneration power plant. The maximum electrical efficiency achieved was around 38% and in all power range unit operated with average potential per single fuel cell higher than 0.60 V. (author)

  2. Performance evaluation of a fuel cell with NiO-YSV anode operating with natural gas; Avaliacao do desempenho de uma celula a combustivel com anodo de NiO YSZ operando com gas natural

    Energy Technology Data Exchange (ETDEWEB)

    Nobrega, Shayenne Diniz da; Vasconcelos, Carmel Suzarte Ayres; Lima, Luiz Rogerio Pinho de Andrade [Universidade Federal da Bahia (UFBa), Salvador, BA (Brazil). Escola Politecnica. Dept. de Ciencia e Tecnologia dos Materiais]. E-mail: shayennedn@yahoo.com.br

    2008-07-01

    Fuel cell is an electrochemical device that converts the chemical energy into electric energy. The natural gas, for its proven improvement in the income of the equipment in relation to other energy ones, has been very used to feed the solid oxide fuel cell (SOFC) in the generation of electric power. Ceramics of Yttria-stabilized zirconia had been used as electrolyte and when supported with nickel oxide they act as anode in the solid oxide fuel cell, due to raised ionic conductivity that these materials present in high temperatures, while lanthanum with strontium and manganite are used as cathode. In the composition of the anode, the concentration of Ni O, acting as catalytic in the YSZ confers high electric conductivity and high electrochemical activity of the reactions, providing the internal reform in the SOFC. In this work, the solid oxide fuel cell, formed by Yttria- stabilized zirconia, nickel oxide, and lanthanum with strontium and manganite were tested in the reform had been prepared samples of electrode/electrolyte for use in SOFC of the natural gas in the presence of low water text, similar condition to the operation of the SOFC, operating in temperatures range from 700 to 800 deg C. This cell also was characterized using the impedance spectroscopy technique. These results allowed the development of components of the current versus voltage. (author)

  3. Integral manifolding structure for fuel cell core having parallel gas flow

    Science.gov (United States)

    Herceg, Joseph E.

    1984-01-01

    Disclosed herein are manifolding means for directing the fuel and oxidant gases to parallel flow passageways in a fuel cell core. Each core passageway is defined by electrolyte and interconnect walls. Each electrolyte and interconnect wall consists respectively of anode and cathode materials layered on the opposite sides of electrolyte material, or on the opposite sides of interconnect material. A core wall projects beyond the open ends of the defined core passageways and is disposed approximately midway between and parallel to the adjacent overlaying and underlying interconnect walls to define manifold chambers therebetween on opposite sides of the wall. Each electrolyte wall defining the flow passageways is shaped to blend into and be connected to this wall in order to redirect the corresponding fuel and oxidant passageways to the respective manifold chambers either above or below this intermediate wall. Inlet and outlet connections are made to these separate manifold chambers respectively, for carrying the fuel and oxidant gases to the core, and for carrying their reaction products away from the core.

  4. Real-Time Analysis of Isoprene in Breath by Using Ultraviolet-Absorption Spectroscopy with a Hollow Optical Fiber Gas Cell.

    Science.gov (United States)

    Iwata, Takuro; Katagiri, Takashi; Matsuura, Yuji

    2016-12-05

    A breath analysis system based on ultraviolet-absorption spectroscopy was developed by using a hollow optical fiber as a gas cell for real-time monitoring of isoprene in breath. The hollow optical fiber functions as an ultra-small-volume gas cell with a long path. The measurement sensitivity of the system was evaluated by using nitric-oxide gas as a gas sample. The evaluation result showed that the developed system, using a laser-driven, high-intensity light source and a 3-m-long, aluminum-coated hollow optical fiber, could successfully measure nitric-oxide gas with a 50 ppb concentration. An absorption spectrum of a breath sample in the wavelength region of around 200-300 nm was measured, and the measured spectrum revealed the main absorbing components in breath as water vapor, isoprene, and ozone converted from oxygen by radiation of ultraviolet light. The concentration of isoprene in breath was estimated by multiple linear regression. The regression analysis results showed that the proposed analysis system enables real-time monitoring of isoprene during the exhaling of breath. Accordingly, it is suitable for measuring the circadian variation of isoprene.

  5. Real-Time Analysis of Isoprene in Breath by Using Ultraviolet-Absorption Spectroscopy with a Hollow Optical Fiber Gas Cell

    Directory of Open Access Journals (Sweden)

    Takuro Iwata

    2016-12-01

    Full Text Available A breath analysis system based on ultraviolet-absorption spectroscopy was developed by using a hollow optical fiber as a gas cell for real-time monitoring of isoprene in breath. The hollow optical fiber functions as an ultra-small-volume gas cell with a long path. The measurement sensitivity of the system was evaluated by using nitric-oxide gas as a gas sample. The evaluation result showed that the developed system, using a laser-driven, high-intensity light source and a 3-m-long, aluminum-coated hollow optical fiber, could successfully measure nitric-oxide gas with a 50 ppb concentration. An absorption spectrum of a breath sample in the wavelength region of around 200–300 nm was measured, and the measured spectrum revealed the main absorbing components in breath as water vapor, isoprene, and ozone converted from oxygen by radiation of ultraviolet light. The concentration of isoprene in breath was estimated by multiple linear regression. The regression analysis results showed that the proposed analysis system enables real-time monitoring of isoprene during the exhaling of breath. Accordingly, it is suitable for measuring the circadian variation of isoprene.

  6. Solid oxide fuel cell/gas turbine trigeneration system for marine applications

    Science.gov (United States)

    Tse, Lawrence Kar Chung; Wilkins, Steven; McGlashan, Niall; Urban, Bernhard; Martinez-Botas, Ricardo

    2011-03-01

    Shipping contributes 4.5% to global CO2 emissions and is not covered by the Kyoto Agreement. One method of reducing CO2 emissions on land is combined cooling heating and power (CCHP) or trigeneration, with typical combined thermal efficiencies of over 80%. Large luxury yachts are seen as an ideal entry point to the off-shore market for this developing technology considering its current high cost. This paper investigates the feasibility of combining a SOFC-GT system and an absorption heat pump (AHP) in a trigeneration system to drive the heating ventilation and air conditioning (HVAC) and electrical base-load systems. A thermodynamic model is used to simulate the system, with various configurations and cooling loads. Measurement of actual yacht performance data forms the basis of this system simulation. It is found that for the optimum configuration using a double effect absorption chiller in Ship 1, the net electric power increases by 47% relative to the electrical power available for a conventional SOFC-GT-HVAC system. This is due to more air cooled to a lower temperature by absorption cooling; hence less electrical cooling by the conventional HVAC unit is required. The overall efficiency is 12.1% for the conventional system, 34.9% for the system with BROAD single effect absorption chiller, 43.2% for the system with double effect absorption chiller. This shows that the overall efficiency of a trigeneration system is far higher when waste heat recovery happens. The desiccant wheel hardly reduces moisture from the outdoor air due to a relative low mass flow rate of fuel cell exhaust available to dehumidify a very large mass flow rate of HVAC air, Hence, desiccant wheel is not recommended for this application.

  7. Reduction reaction of chlorine gas in an Al-Cl2 chemical cell composed of molten chloride salts; Enkabutsu yoyuenkei Al-Cl2 kagaku denchi ni okeru enso gas no kangen hanno kyodo

    Energy Technology Data Exchange (ETDEWEB)

    Konda, S.; Sasaki, T.; Ishikawa, T. [Hokkaido University, Sapporo (Japan)

    1996-10-05

    The molten salt system electrochemical cycle was proposed to reproduce pure Al from scrap Al. The cycle is composed of production of rough AlCl3 by chlorination of scrap Al, refining of rough AlCl3 mainly by sublimation, and electrolytic reproduction of pure Al from refined AlCl3. In production of AlCl3, the Al-Cl2 molten salt system cell composed of anode dissolution reaction of Al and cathode reduction reaction of chlorine gas can generate electric power for the electrolytic reproduction. Chlorine gas can be recycled as anode product. Various experiments were carried out to improve molten salt system cells. In analysis of cell output, voltage drop from open circuit voltage was divided into that due to electrolytic bath resistance, and that due to reaction resistance. The electrolytic bath resistance could be determined from transient characteristics of voltage change just after cutoff of output current. The product of the obtained reaction resistance and a meniscus length was constant regardless of a meniscus length, and useful to predict scale-up cell performance. Output characteristics dependent on meniscus position were also obtained. 16 refs., 11 figs.

  8. Accelerated production of antigen-specific T-cells for pre-clinical and clinical applications using Gas-permeable Rapid Expansion cultureware (G-Rex)

    Science.gov (United States)

    Vera, Juan F.; Brenner, Lara J.; Gerdemann, Ulrike; Ngo, Minhtran C.; Sili, Uluhan; Liu, Hao; Wilson, John; Dotti, Gianpietro; Heslop, Helen E.; Leen, Ann M.; Rooney, Cliona M.

    2009-01-01

    The clinical manufacture of antigen-specific cytotoxic T lymphocytes (CTL) for adoptive immunotherapy is limited by the complexity and time required to produce large numbers with the desired function and specificity. The culture conditions required are rigorous, and in some cases only achieved in 2cm2 wells in which cell growth is limited by gas exchange, nutrients and waste accumulation. Bioreactors developed to overcome these issues tend to be complex, expensive and not always conducive to CTL growth. We observed that antigen-specific CTL undergo seven to ten divisions post-stimulation. However the expected CTL numbers were achieved only in the first week of culture. By recreating the culture conditions present during this first week - low frequency of antigen-specific T-cells and high frequency of feeder cells - we were able to increase CTL expansion to expected levels which could be sustained for several weeks without affecting phenotype or function. However, the number of 24-well plates needed was excessive and cultures required frequent media changes, increasing complexity and manufacturing costs. Therefore, we evaluated novel gas-permeable culture devices (G-Rex) with a silicone membrane at the base allowing gas exchange to occur uninhibited by depth of medium above. This system effectively supports the expansion of CTL and actually increases output by up to 20-fold while decreasing required technician time. Importantly, this amplified cell expansion is not due to more cell divisions but to reduced cell death. This bioprocess optimization increased T-cell output while decreasing the complexity and cost of CTL manufacture, making cell therapy more accessible. PMID:20445351

  9. A novel microbial fuel cell sensor with a gas diffusion biocathode sensing element for water and air quality monitoring.

    Science.gov (United States)

    Jiang, Yong; Liang, Peng; Huang, Xia; Ren, Zhiyong Jason

    2018-07-01

    Toxicity monitoring is essential for the protection of public health and ecological safety. Microbial fuel cell (MFC) sensors demonstrated good potential in toxicity monitoring, but current MFC sensors can only be used for anaerobic water monitoring. In this study, a novel gas diffusion (GD)-biocathode sensing element was fabricated using a simple method. The GD-biocathode MFC sensor can directly be used for formaldehyde detection (from 0.0005% to 0.005%) in both aerobic and anaerobic water bodies. Electrochemical analysis indicated that the response by the sensor was caused by the toxic inhibition to the microbial activity for the oxygen reduction reaction (ORR). This study for the first time demonstrated that the GD-biocathode MFC sensor has a detection limit of 20 ppm for formaldehyde and can be used to monitor air pollution. Selective sensitivity to formaldehyde was not achieved as the result of using a mixed-culture, which confirms that it can serve as a generic biosensor for monitoring gaseous pollutants. This study expands the realm of knowledge for MFC sensor applications. Copyright © 2018 Elsevier Ltd. All rights reserved.

  10. Gas diffusion electrode based on electrospun Pani/CNF nanofibers hybrid for proton exchange membrane fuel cells (PEMFC) applications

    Energy Technology Data Exchange (ETDEWEB)

    Hezarjaribi, M.; Jahanshahi, M., E-mail: mjahan@nit.ac.ir; Rahimpour, A.; Yaldagard, M.

    2014-03-01

    A novel hybrid system has been investigated based on polyaniline/carbon nanofiber (Pani/CNF) electrospun nanofibers for modification of gas diffusion electrode (GDE) in proton exchange membrane fuel cells (PEMFC). Pani/CNF hybrid nanofibers were synthesized directly on carbon paper by electrospinning method. For preparation of catalyst ink, 20 wt.% Pt/C electrocatalyst with a platinum loading of 0.4 mg cm{sup −2} was prepared by polyol technique. SEM studies applied for morphological study of the modified GDE with hybrid nanofibers. This technique indicated that the electrospun nanofibers had a diameter of roughly 100 nm. XRD patterns also showed that the average size of Pt nanoparticles was about 2 nm. Subsequently, comparison of the hybrid electrode electrochemical behavior and 20 wt.% Pt/C commercial one was studied by cyclic voltammetry experiment. The electrochemical data indicated that the hybrid electrode exhibited higher current density (about 15 mA cm{sup −2}) and ESA (160 m{sup 2} gr{sup −1}) than commercial Pt/C with amount of about 10 mA cm{sup −2} and 114 m{sup 2} gr{sup −1}, respectively. The results herein demonstrate that Pani/CNF nanofibers can be used as a good alternative electrode material for PEMFCs.

  11. Feasibility study of solid oxide fuel cell engines integrated with sprinter gas turbines: Modeling, design and control

    Science.gov (United States)

    Jia, Zhenzhong; Sun, Jing; Dobbs, Herb; King, Joel

    2015-02-01

    Conventional recuperating solid oxide fuel cell (SOFC)/gas turbine (GT) system suffers from its poor dynamic capability and load following performance. To meet the fast, safe and efficient load following requirements for mobile applications, a sprinter SOFC/GT system concept is proposed in this paper. In the proposed system, an SOFC stack operating at fairly constant temperature provides the baseline power with high efficiency while the fast dynamic capability of the GT-generator is fully explored for fast dynamic load following. System design and control studies have been conducted by using an SOFC/GT system model consisting of experimentally-verified component models. In particular, through analysis of the steady-state simulation results, an SOFC operation strategy is proposed to maintain fairly constant SOFC power (less than 2% power variation) and temperature (less than 2 K temperature variation) over the entire load range. A system design procedure well-suited to the proposed system has also been developed to help determining component sizes and the reference steady-state operation line. In addition, control analysis has been studied for both steady-state and transient operations. Simulation results suggest that the proposed system holds the promise to achieve fast and safe transient operations by taking full advantage of the fast dynamics of the GT-generator.

  12. Study of a hybrid system using solid oxide fuel cells (SOFC) and gas turbine; Estudo de um sistema hibrido empregando celula de combustivel de oxido solido (SOFC) e turbina a gas

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Antonio Carlos Caetano de; Gallo, Giulliano Batelochi; Silveira, Jose Luz [UNESP, Guaratingueta, SP (Brazil). Faculdade de Engenharia. Dept. de Energia], e-mail: caetano@feg.unesp.br

    2004-07-01

    In this paper a hybrid solid oxide fuel cell (SOFC) system, applying a combined cycle using gas turbine for rational decentralized energy production is analyzed. The relative concepts about the fuel cell are presented, followed by some chemical and technical information such as the change of Gibbs free energy in isothermal fuel oxidation directly into electricity. This represents a very high fraction of the lower heating value (LHV) of a hydrocarbon fuel. In the next step a methodology for the study of SOFC and gas turbine system is developed, considering the electricity and steam production for a hospital. This methodology is applied to energetic analysis. Natural gas is considered as a fuel. A Sankey Diagram shows that the hybrid SOFC system is a good opportunity to strengthen the decentralized energy production in Brazil. It is necessary to consider that the cogeneration in this version also is a good technical alternative, demanding special methods of design, equipment selection and contractual deals associated to electricity and fuel supply. (author)

  13. Effect of the hydrophilic and hydrophobic characteristics of the gas diffusion medium on polymer electrolyte fuel cell performance under non-humidification condition

    International Nuclear Information System (INIS)

    Park, Heesung

    2014-01-01

    Highlights: • GDM played significant role in the PEFC performance under dry condition. • Hydrophobicity of GDM affect the water condensation at the surface. • Optimum water saturation in the porous layer was between 0.1 and 0.3. - Abstract: Water is a significant component of polymer electrolyte fuel cells, affecting the proton conductivity in the membrane electrolyte. Therefore, polymer electrolyte fuel cells are generally operated with a humidifier to maintain a high relative humidity of the supplied gases; however, the humidifier contributes additional weight and cost. Although many studies have attempted to develop polymer electrolyte fuel cells without a humidifier, the studies have been mainly focused on the self-humidified membrane electrolyte and catalyst layer. In this paper, the author investigates the effect of polytetrafluoroethylene coated gas diffusion medium on the water content in the membrane electrolyte. The water condensation on the surfaces of the gas diffusion medium is visualised when the polymer electrolyte fuel cell is operated under non-humidification conditions. Numerical simulation suggests that the optimum water saturation is between 0.1 and 0.3 at the gas diffusion medium to hydrate the membrane electrolyte sufficiently without significantly blocking the diffused species under non-humidification conditions

  14. Effect of the prominent catalyst layer surface on reactant gas transport and cell performance at the cathodic side of a PEMFC

    International Nuclear Information System (INIS)

    Perng, Shiang-Wuu; Wu, Horng-Wen

    2010-01-01

    The cell performance enhancement of a proton exchange membrane fuel cell (PEMFC) has been numerically investigated with the prominence-like form catalyst layer surface of the same composition at the cathodic half-cell of a PEMFC. The geometries of the prominence-like form catalyst layer surface are assigned as one prominence, three prominences, and five prominences catalyst layer surfaces with constant distance between two prominences in the same gas diffusion layer (GDL) for the purpose of investigating the cell performance. To confine the current investigation to two-dimensional incompressible flows, we assume that the fluid flow is laminar with a low Reynolds number 15. The results indicate that the prominence-like form catalyst layer surface can effectively enhance the local cell performance of a PEMFC.

  15. A multi-level simulation platform of natural gas internal reforming solid oxide fuel cell-gas turbine hybrid generation system - Part II. Balancing units model library and system simulation

    Science.gov (United States)

    Bao, Cheng; Cai, Ningsheng; Croiset, Eric

    2011-10-01

    Following our integrated hierarchical modeling framework of natural gas internal reforming solid oxide fuel cell (IRSOFC), this paper firstly introduces the model libraries of main balancing units, including some state-of-the-art achievements and our specific work. Based on gPROMS programming code, flexible configuration and modular design are fully realized by specifying graphically all unit models in each level. Via comparison with the steady-state experimental data of Siemens-Westinghouse demonstration system, the in-house multi-level SOFC-gas turbine (GT) simulation platform is validated to be more accurate than the advanced power system analysis tool (APSAT). Moreover, some units of the demonstration system are designed reversely for analysis of a typically part-load transient process. The framework of distributed and dynamic modeling in most of units is significant for the development of control strategies in the future.

  16. Improvements to laser wakefield accelerated electron beam stability, divergence, and energy spread using three-dimensional printed two-stage gas cell targets

    International Nuclear Information System (INIS)

    Vargas, M.; Schumaker, W.; He, Z.-H.; Zhao, Z.; Behm, K.; Chvykov, V.; Hou, B.; Krushelnick, K.; Maksimchuk, A.; Yanovsky, V.; Thomas, A. G. R.

    2014-01-01

    High intensity, short pulse lasers can be used to accelerate electrons to ultra-relativistic energies via laser wakefield acceleration (LWFA) [T. Tajima and J. M. Dawson, Phys. Rev. Lett. 43, 267 (1979)]. Recently, it was shown that separating the injection and acceleration processes into two distinct stages could prove beneficial in obtaining stable, high energy electron beams [Gonsalves et al., Nat. Phys. 7, 862 (2011); Liu et al., Phys. Rev. Lett. 107, 035001 (2011); Pollock et al., Phys. Rev. Lett. 107, 045001 (2011)]. Here, we use a stereolithography based 3D printer to produce two-stage gas targets for LWFA experiments on the HERCULES laser system at the University of Michigan. We demonstrate substantial improvements to the divergence, pointing stability, and energy spread of a laser wakefield accelerated electron beam compared with a single-stage gas cell or gas jet target

  17. Improvements to laser wakefield accelerated electron beam stability, divergence, and energy spread using three-dimensional printed two-stage gas cell targets

    Energy Technology Data Exchange (ETDEWEB)

    Vargas, M.; Schumaker, W.; He, Z.-H.; Zhao, Z.; Behm, K.; Chvykov, V.; Hou, B.; Krushelnick, K.; Maksimchuk, A.; Yanovsky, V.; Thomas, A. G. R., E-mail: agrt@umich.edu [Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Michigan 48109 (United States)

    2014-04-28

    High intensity, short pulse lasers can be used to accelerate electrons to ultra-relativistic energies via laser wakefield acceleration (LWFA) [T. Tajima and J. M. Dawson, Phys. Rev. Lett. 43, 267 (1979)]. Recently, it was shown that separating the injection and acceleration processes into two distinct stages could prove beneficial in obtaining stable, high energy electron beams [Gonsalves et al., Nat. Phys. 7, 862 (2011); Liu et al., Phys. Rev. Lett. 107, 035001 (2011); Pollock et al., Phys. Rev. Lett. 107, 045001 (2011)]. Here, we use a stereolithography based 3D printer to produce two-stage gas targets for LWFA experiments on the HERCULES laser system at the University of Michigan. We demonstrate substantial improvements to the divergence, pointing stability, and energy spread of a laser wakefield accelerated electron beam compared with a single-stage gas cell or gas jet target.

  18. Hydrogen Oxidation on Gas Diffusion Electrodes for Phosphoric Acid Fuel Cells in the Presence of Carbon Monoxide and Oxygen

    DEFF Research Database (Denmark)

    Gang, Xiao; Li, Qingfeng; Hjuler, Hans Aage

    1995-01-01

    Hydrogen oxidation has been studied on a carbon-supported platinum gas diffusion electrode in a phosphoric acidelectrolyte in the presence of carbon monoxide and oxygen in the feed gas. The poisoning effect of carbon monoxide presentin the feed gas was measured in the temperature range from 80...... to 150°C. It was found that throughout the temperaturerange, the potential loss due to the CO poisoning can be reduced to a great extent by the injection of small amounts ofgaseous oxygen into the hydrogen gas containing carbon monoxide. By adding 5 volume percent (v/o) oxygen, an almost...

  19. Involvement of placental/umbilical cord blood acid-base status and gas values on the radiosensitivity of human fetal/neonatal hematopoietic stem/progenitor cells

    International Nuclear Information System (INIS)

    Yamaguchi, Masaru; Ebina, Satoko; Kashiwakura, Ikuo

    2013-01-01

    Arterial cord blood (CB) acid-base status and gas values, such as pH, PCO 2 , PO 2 , HCO 3 - and base excess, provide useful information on the fetal and neonatal condition. However, it remains unknown whether these values affect the radiosensitivity of fetal/neonatal hematopoiesis. The present study evaluated the relationship between arterial CB acid-base status, gas values, and the radiosensitivity of CB hematopoietic stem/progenitor cells (HSPCs). A total of 25 CB units were collected. The arterial CB acid-base status and gas values were measured within 30 min of delivery. The CD34 + HSPCs obtained from CB were exposed to 2 Gy X-irradiation, and then assayed for colony-forming unit-granulocyte-macrophage, burst-forming unit-erythroid (BFU-E), and colony-forming unit-granulocyte erythroid, macrophage and megakaryocyte cells. Acid-base status and gas values for PCO 2 and HCO 3 - showed a statistically significant negative correlation with the surviving fraction of BFU-E. In addition, a significant positive correlation was observed between gestational age and PCO 2 . Moreover, the surviving fraction of BFU-E showed a significant negative correlation with gestational age. Thus, HSPCs obtained from CB with high PCO 2 /HCO 3 - levels were sensitive to X-irradiation, which suggests that the status of arterial PCO 2 /HCO 3 - influences the radiosensitivity of fetal/neonatal hematopoiesis, especially erythropoiesis. (author)

  20. Stall/surge dynamics of a multi-stage air compressor in response to a load transient of a hybrid solid oxide fuel cell-gas turbine system

    Science.gov (United States)

    Azizi, Mohammad Ali; Brouwer, Jacob

    2017-10-01

    A better understanding of turbulent unsteady flows in gas turbine systems is necessary to design and control compressors for hybrid fuel cell-gas turbine systems. Compressor stall/surge analysis for a 4 MW hybrid solid oxide fuel cell-gas turbine system for locomotive applications is performed based upon a 1.7 MW multi-stage air compressor. Control strategies are applied to prevent operation of the hybrid SOFC-GT beyond the stall/surge lines of the compressor. Computational fluid dynamics tools are used to simulate the flow distribution and instabilities near the stall/surge line. The results show that a 1.7 MW system compressor like that of a Kawasaki gas turbine is an appropriate choice among the industrial compressors to be used in a 4 MW locomotive SOFC-GT with topping cycle design. The multi-stage radial design of the compressor enhances the ability of the compressor to maintain air flow rate during transient step-load changes. These transient step-load changes are exhibited in many potential applications for SOFC/GT systems. The compressor provides sustained air flow rate during the mild stall/surge event that occurs due to the transient step-load change that is applied, indicating that this type of compressor is well-suited for this hybrid application.

  1. Catalytic properties of the Gas family β-(1,3)-glucanosyltransferases active in fungal cell-wall biogenesis as determined by a novel fluorescent assay.

    Science.gov (United States)

    Mazáň, Marián; Ragni, Enrico; Popolo, Laura; Farkaš, Vladimír

    2011-09-01

    BGTs [β-(1,3)-glucanosyltransglycosylases; EC 2.4.1.-] of the GH72 (family 72 of glycosylhydrolases) are GPI (glycosylphosphatidylinositol)-anchored proteins that play an important role in the biogenesis of fungal cell walls. They randomly cleave glycosidic linkages in β-(1,3)-glucan chains and ligate the polysaccharide portions containing newly formed reducing ends to C(3)(OH) at non-reducing ends of other β-(1,3)-glucan molecules. We have developed a sensitive fluorescence-based method for the assay of transglycosylating activity of GH72 enzymes. In the new assay, laminarin [β-(1,3)-glucan] is used as the glucanosyl donor and LamOS (laminarioligosaccharides) fluorescently labelled with SR (sulforhodamine) serve as the acceptors. The new fluorescent assay was employed for partial biochemical characterization of the heterologously expressed Gas family proteins from the yeast Saccharomyces cerevisiae. All the Gas enzymes specifically used laminarin as the glucanosyl donor and a SR-LamOS of DP (degree of polymerization) ≥5 as the acceptors. Gas proteins expressed in distinct stages of the yeast life cycle showed differences in their pH optima. Gas1p and Gas5p, which are expressed during vegetative growth, had the highest activity at pH 4.5 and 3.5 respectively, whereas the sporulation-specific Gas2p and Gas4p were most active between pH 5 and 6. The novel fluorescent assay provides a suitable tool for the screening of potential glucanosyltransferases or their inhibitors.

  2. Preparation and Loading Process of Single Crystalline Samples into a Gas Environmental Cell Holder for In Situ Atomic Resolution Scanning Transmission Electron Microscopic Observation.

    Science.gov (United States)

    Straubinger, Rainer; Beyer, Andreas; Volz, Kerstin

    2016-06-01

    A reproducible way to transfer a single crystalline sample into a gas environmental cell holder for in situ transmission electron microscopic (TEM) analysis is shown in this study. As in situ holders have only single-tilt capability, it is necessary to prepare the sample precisely along a specific zone axis. This can be achieved by a very accurate focused ion beam lift-out preparation. We show a step-by-step procedure to prepare the sample and transfer it into the gas environmental cell. The sample material is a GaP/Ga(NAsP)/GaP multi-quantum well structure on Si. Scanning TEM observations prove that it is possible to achieve atomic resolution at very high temperatures in a nitrogen environment of 100,000 Pa.

  3. New process of the preparation of catalyzed gas diffusion electrode for PEM fuel cells based on ultrasonic direct solution spray reaction method

    Energy Technology Data Exchange (ETDEWEB)

    Oishi, K.; Savadogo, O. [Ecole Polytechnique de Montreal, Montreal, PQ (Canada). Laboratoire de nouveaux materiaux pour l' energie et l' electrochimie

    2008-07-01

    This paper reported on a newly developed process for in-situ catalyst deposition on gas diffusion electrodes (GDE) for polymer electrolyte fuel cells. This process has the potential to reduce the number of steps for catalyzed GDE fabrication. In addition, the process offers economic advantages for the fuel cell commercialization. In this study, a home-made catalyst maker with ultrasonic spray method was used to prepare a solution of the carbon supported platinum catalyst on the GDL. The sprayed catalyst powder consisted of carbon support. The catalyst particles did not prevent gas flow channels on the GDL. The catalyst layer was shown to be located only on the top surface of the GDL and was not packed into its flow channel. Results of Cross-section SEM image, crystallization, micro structure and electro-catalytic activity for the oxygen reduction reaction were also discussed. 1 ref., 1 fig.

  4. Study of ions - molecules reactions in the gas phase with collision reaction cell devices: Applications to the direct resolution of spectroscopic interferences in ICP-MS

    International Nuclear Information System (INIS)

    Favre, G.

    2008-12-01

    Inductively Coupled Plasma Mass Spectrometry emerged as the most widespread mass spectrometry technique in inorganic analytical chemistry for determining the concentration of a given isotope or an isotope ratio. The problem of spectroscopic interferences, inherent to this technique, finds a solution through the use of reaction cell devices. An in situ interference removal is feasible with the addition of a well selected gas in the cell. The understanding of the chemistry of ions-molecules interactions in the gas phase is however fundamental to optimize the efficiency of such devices. An accurate knowledge of experimental conditions in the reaction zone according to instrumental parameters appears crucial in order to interpret observed reactivities. This preliminary study is then used for the resolution of two nuclear field characteristic interferences. (author)

  5. Determination of hydrogen in zirconium and its alloys by melt extraction under carrier gas flow using thermal conductivity cell as detector

    International Nuclear Information System (INIS)

    Akhtar, J.; Ahmed, M.; Mohammad, B.; Jan, S.; Waqar, F.

    1987-06-01

    In the production of zirconium metal and its alloys the presence of hydrogen impurity affects mechanical and corrosion resistance properties of the product. Therefore, determination of hydrogen contents of the product is necessary. Conditions for its analysis by melt extraction under carrier gas stream using thermal conductivity cell as detector were studied and optimised. The method is capable of measuring hydrogen impurity in parts per million range. (author)

  6. Phenomenological theory of current-producing processes at the solid oxide electrolyte/gas electrode interface: steady-state polarization of fuel-cell electrodes

    International Nuclear Information System (INIS)

    Murygin, I.V.; Chebotin, V.N.

    1979-01-01

    The polarization of fuel-cell electrodes (mixtures CO + CO 2 and H 2 + H 2 O) in systems with solid oxide electrolytes is discussed. The theory is based upon a process model where the electrode reaction zone can spread along the line of three-phase contact by diffusion of reaction partners and products across the electrolyte/electrode and electrolyte/gas interface

  7. Pilot experiments with relativistic uranium projectile and fission fragments thermalized in a cryogenic gas-filled stopping cell

    Energy Technology Data Exchange (ETDEWEB)

    Reiter, Moritz Pascal

    2015-07-01

    online experiments, which is about three times larger than any stopping cell, using RF structures for the extraction of ions, has demonstrated. The area density and therefore the stopping power of the CSC is limited by the differential pumping. To overcome this limitation the CSC was tested with neon as a stopping gas with area densities of up to 11.3 mg/cm{sup 2} helium equivalent, demonstrating a unprecedented area density for stopping cells based on RF structures. The RF carpet performed reliably and its potential for the future FAIR stopping cell was shown. During the experiments at GSI the mean extraction time of {sup 221}Ac ions from the CSC to a silicon surface detector was measured, it amounts to 24 ms. This value is well in agreement with offline measurements using a pulsed {sup 223}Ra recoil ion source. The combination of a high density stopping cell with high total efficiencies and a non-scanning high-resolution mass spectrometer can be used as an independent identification detector for exotic nuclei by their mass, allowing a recalibration of the in-flight detectors of any fragment separator. As a proof-of-principal experiment the CSC and a MR-TOF-MS have been used as a mass tagger for the FRS at GSI. 134-I ions were produced by in-flight fission from an {sup 238}U primary beam at 1000 MeV/u and identified by the mass tagger. The new method does not rely on specific decay properties and therefore allows a recalibration of the fragment separator independent of the fragment and can also be used with stable nuclides. The usage of the CSC and a MR-TOF-MS will allow fast recalibration and a more effective usage of the limited amount of beam time for all experiments with exotic nuclei even in the case the nuclide of interest is not clearly identified by the in-flight detection scheme. With the CSC low energy experiments such as high-precision mass measurements and decay spectroscopy were made possible, the half lifes of {sup 221}Ac and {sup 223}Th have been measured

  8. Pilot experiments with relativistic uranium projectile and fission fragments thermalized in a cryogenic gas-filled stopping cell

    International Nuclear Information System (INIS)

    Reiter, Moritz Pascal

    2015-01-01

    experiments, which is about three times larger than any stopping cell, using RF structures for the extraction of ions, has demonstrated. The area density and therefore the stopping power of the CSC is limited by the differential pumping. To overcome this limitation the CSC was tested with neon as a stopping gas with area densities of up to 11.3 mg/cm"2 helium equivalent, demonstrating a unprecedented area density for stopping cells based on RF structures. The RF carpet performed reliably and its potential for the future FAIR stopping cell was shown. During the experiments at GSI the mean extraction time of "2"2"1Ac ions from the CSC to a silicon surface detector was measured, it amounts to 24 ms. This value is well in agreement with offline measurements using a pulsed "2"2"3Ra recoil ion source. The combination of a high density stopping cell with high total efficiencies and a non-scanning high-resolution mass spectrometer can be used as an independent identification detector for exotic nuclei by their mass, allowing a recalibration of the in-flight detectors of any fragment separator. As a proof-of-principal experiment the CSC and a MR-TOF-MS have been used as a mass tagger for the FRS at GSI. 134-I ions were produced by in-flight fission from an "2"3"8U primary beam at 1000 MeV/u and identified by the mass tagger. The new method does not rely on specific decay properties and therefore allows a recalibration of the fragment separator independent of the fragment and can also be used with stable nuclides. The usage of the CSC and a MR-TOF-MS will allow fast recalibration and a more effective usage of the limited amount of beam time for all experiments with exotic nuclei even in the case the nuclide of interest is not clearly identified by the in-flight detection scheme. With the CSC low energy experiments such as high-precision mass measurements and decay spectroscopy were made possible, the half lifes of "2"2"1Ac and "2"2"3Th have been measured, alpha spectroscopy of short

  9. Characterization and improvement gas diffusion layer of low temperature fuel cell; Caracterizacao e aprimoramento da camada difusora de celulas a combustivel de funcionamento a baixa temperatura

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, C.Z.; Dantas, R.; Oliveira, I.S. de; Azevedo, C.M.N.; Pires, M. [Pontificia Univ. Catolica do Rio Grande do Sul (PUC-RS), Porto Alegre, RS (Brazil). Faculdade de Quimica; Canalli, V. [Pontificia Univ. Catolica do Rio Grande do Sul (PUC-RS), Porto Alegre, RS (Brazil). Faculdade de Engenharia

    2006-07-01

    In low temperature fuel cells the main part is the membrane electrode assembly (MEA). The gas diffusion layer is a component of the MEA, being a composite material constituted by carbon powder and polytetrafluoroethylene, used to increases hydrofobicity, fundamental characteristic in water transport into system. In this work methods were adapted with the aim to a better characterization of the diffusion layer by the measuring the following parameter: contact angle and hysteresis; morphology, thickness and porosity. From these characterization results optimized MEAS will be produced to better fuel cell performance. (author)

  10. Gas turbine

    International Nuclear Information System (INIS)

    Yang, Ok Ryong

    2004-01-01

    This book introduces gas turbine cycle explaining general thing of gas turbine, full gas turbine cycle, Ericson cycle and Brayton cycle, practical gas turbine cycle without pressure loss, multiaxial type gas turbine cycle and special gas turbine cycle, application of basic theory on a study on suction-cooling gas turbine cycle with turbo-refrigerating machine using the bleed air, and general performance characteristics of the suction-cooling gas turbine cycle combined with absorption-type refrigerating machine.

  11. Direct and inverse neural networks modelling applied to study the influence of the gas diffusion layer properties on PBI-based PEM fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Lobato, Justo; Canizares, Pablo; Rodrigo, Manuel A.; Linares, Jose J. [Chemical Engineering Department, University of Castilla-La Mancha, Campus Universitario s/n, 13004 Ciudad Real (Spain); Piuleac, Ciprian-George; Curteanu, Silvia [Faculty of Chemical Engineering and Environmental Protection, Department of Chemical Engineering, ' ' Gh. Asachi' ' Technical University Iasi Bd. D. Mangeron, No. 71A, 700050 IASI (Romania)

    2010-08-15

    This article shows the application of a very useful mathematical tool, artificial neural networks, to predict the fuel cells results (the value of the tortuosity and the cell voltage, at a given current density, and therefore, the power) on the basis of several properties that define a Gas Diffusion Layer: Teflon content, air permeability, porosity, mean pore size, hydrophobia level. Four neural networks types (multilayer perceptron, generalized feedforward network, modular neural network, and Jordan-Elman neural network) have been applied, with a good fitting between the predicted and the experimental values in the polarization curves. A simple feedforward neural network with one hidden layer proved to be an accurate model with good generalization capability (error about 1% in the validation phase). A procedure based on inverse neural network modelling was able to determine, with small errors, the initial conditions leading to imposed values for characteristics of the fuel cell. In addition, the use of this tool has been proved to be very attractive in order to predict the cell performance, and more interestingly, the influence of the properties of the gas diffusion layer on the cell performance, allowing possible enhancements of this material by changing some of its properties. (author)

  12. Vitamin K2 inhibits rat vascular smooth muscle cell calcification by restoring the Gas6/Axl/Akt anti-apoptotic pathway.

    Science.gov (United States)

    Qiu, Cuiting; Zheng, Haijun; Tao, Huiren; Yu, Wenjun; Jiang, Xiaoyu; Li, Aiqin; Jin, Hui; Lv, Anlin; Li, Huan

    2017-09-01

    Vascular calcification is associated with cardiovascular disease as a complication of hypertension, hyperlipidemia, diabetes mellitus, and chronic kidney disease. Vitamin K2 (VK2) delays vascular calcification by an unclear mechanism. Moreover, apoptosis modulates vascular smooth muscle cell (VSMC) calcification. This paper aimed to study VK2-modified VSMC calcification and survival cell signaling mediated by growth arrest-specific gene 6 (Gas6) and its tyrosine kinase receptor Axl. Primary-cultured VSMCs were dose-dependently treated with VK2 in the presence of calcification medium for 8 days, or pre-treated for 1 h with/without the Axl inhibitor R428 (2 μmol/L) or the caspase inhibitor Z-VAD-fmk (20 μmol/L) followed by treatment with VK2 (10 μmol/L) or rmGas6 (200 nmol/L) in calcification medium for 8 days. Calcium deposition was determined by the o-cresolphthalein complexone assay and Alizarin Red S staining. Apoptosis was determined by TUNEL and flow cytometry using Annexin V-FITC and propidium iodide staining. Western blotting detected the expressions of Axl, Gas6, p-Akt, Akt, and Bcl2. VK2 significantly inhibited CaCl 2 - and β-sodium glycerophosphate (β-GP)-induced VSMC calcification and apoptosis, which was dependent on restored Gas6 expression and activated downstream signaling by Axl, p-Akt, and Bcl2. Z-VAD-fmk significantly inhibited CaCl 2 - and β-GP-induced VSMC calcification and apoptosis. Augmented recombinant mouse Gas6 protein (rmGas6) expression significantly reduced VSMC calcification and apoptosis. Furthermore, the Gas6/Axl interaction was inhibited by R428, which abolished the preventive effect of VK2 on CaCl 2 - and β-GP-induced apoptosis and calcification. These results suggest that Gas6 is critical in VK2-mediated functions that attenuate CaCl 2 - and β-GP-induced VSMC calcification by blocking apoptosis.

  13. Design and production of a proton exchange membrane fuel cell for the production of brown's gas

    International Nuclear Information System (INIS)

    Essuman, Samuel Pamford Kojo

    2017-07-01

    The use of petroleum products (fossil fuels) has raised a lot of environmental concerns over the past years. This is due to the fact that most of the machines and devices manufactured are engineered to use these conventional fuels which include petrol, diesel and natural gas. However, these fuels substances pollute and deteriorate the quality of the environment. Some of these pollutants include sulphur oxides, nitrogen oxides, particulate matter, and ozone. These gases are called greenhouse gases because they contribute to the greenhouse effect. These gases also cause depletion of the ozone layer. In the search for alternative fuels, researchers have used improved technologies such as steam reforming, partial oxidation, and electrolysis among many to produce hydrogen gas. Hydrogen gas is used in modern times for varied applications in industries and is now been considered as a viable primary fuel for the future. Meanwhile, all these methods produce impure hydrogen except electrolysis of water. Electrolysis of water produces hydrogen and oxygen as products gases. A collection of these gases through a common outlet gives rise to a unique type of gas called Brown’s or oxyhydrogen gas. Brown’s gas is a mixture of oxygen and hydrogen bonded magnetically in a ratio of 1:2. In the automobile industry, Brown’s gas is used as a fuel supplement to gasoline in internal combustion engines (ICEs), as well as welding and cutting of iron plates in the fabrication sector. In this project, a fabricated oxyhydrogen generator was used to produce Brown’s gas from distilled water using three selected catalyst namely caustic soda (KOH), sodium hydroxide (NaOH) and sodium bicarbonate (NaHCO3). Parameters that influence the yield of oxyhydrogen gas were further studied. It was observed that increasing in the number of electrodes, catalyst concentration, voltage and time increased the yield of oxyhydrogen gas production. With the rapid increase in consumption of fossil fuels and

  14. Experimental study on the membrane electrode assembly of a proton exchange membrane fuel cell: effects of microporous layer, membrane thickness and gas diffusion layer hydrophobic treatment

    International Nuclear Information System (INIS)

    Ferreira, Rui B.; Falcão, D.S.; Oliveira, V.B.; Pinto, A.M.F.R.

    2017-01-01

    Highlights: • EIS is employed to investigate the MEA design of a PEM fuel cell. • Effects of MPL, membrane thickness and GDL hydrophobic treatment are studied. • MPL increases cell output at low to medium currents but reduces it at high currents. • Better results are obtained when employing a thinner Nafion membrane. • GDL hydrophobic treatment improves the cell performance. - Abstract: In this study, electrochemical impedance spectroscopy (EIS) is employed to analyze the influence of microporous layer (MPL), membrane thickness and gas diffusion layer (GDL) hydrophobic treatment in the performance of a proton exchange membrane (PEM) fuel cell. Results show that adding a MPL increases cell performance at low to medium current densities. Because lower ohmic losses are observed when applying a MPL, such improvement is attributed to a better hydration state of the membrane. The MPL creates a pressure barrier for water produced at the cathode, forcing it to travel to the anode side, therefore increasing the water content in the membrane. However, at high currents, this same phenomenon seems to have intensified liquid water flooding in the anode gas channels, increasing mass transfer losses and reducing the cell performance. Decreasing membrane thickness results into considerably higher performances, due to a decrease in ohmic resistance. Moreover, at low air humidity operation, a rapid recovery from dehydration is observed when a thinner membrane is employed. The GDL hydrophobic treatment significantly improves the cell performance. Untreated GDLs appear to act as water-traps that not only hamper reactants transport to the reactive sites but also impede the proper humidification of the cell. From the different designs tested, the highest maximum power density is obtained from that containing a MPL, a thinner membrane and treated GDLs.

  15. Experimental and Numerical Study of the Effect of Gas-Shrouded Plasma Spraying on Cathode Coating of Alkaline Electrolysis Cells

    Science.gov (United States)

    Liu, T.; Reißner, R.; Schiller, G.; Ansar, A.

    2018-01-01

    The aim of this work is to improve the performance of electrodes prepared via atmospheric plasma spray by means of gas shrouding which is expected to apparently reduce the oxygen content of the plasma plume and subsequently improve the coating quality. Electrodes with dual-layer coating for alkaline water electrolysis were deposited on Ni-coated perforated substrates. Microstructure and morphology were studied by SEM. Element content was measured by EDS. Enthalpy probe was employed for measuring plasma temperature and velocity as well as the gas composition. For verifying and better understanding the shrouding effect numerical calculation was carried out according to the experimental settings. Electrochemical test was carried out to validate the shrouding effect. The results showed slight protecting effect of gas shrouding on plasma plume and the final coating. Over the dual-layer section, the measured oxygen fraction was 3.46 and 3.15% for the case without gas shrouding and with gas shrouding, respectively. With gas shrouding the coating exhibited similar element contents as the coating sprayed by VPS, while no obvious improvement was observed in the microstructure or the morphology. Evident electrochemical improvement was nevertheless achieved that with gas shrouding the electrode exhibited similar performance as that of the VPS-sprayed electrode.

  16. Preparation of gas diffusion layers for PEMFC fuel cells using carbon fibers; Elaboracao de uma camada de difusao de gas a partir de fibras de carbono para aplicacao em celulas combustiveis do tipo PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Santos, J.N.; Kunsti, S.R.; Malfatti, C.F. [Universidade Federal do Rio Grande do Sul - Departamento de Metalurgia (PPGEM) - Laboratorio de Pesquisa em Corrosao (LAPEC), Porto Alegre, RS (Brazil); Vargas, J.V.C. [Universidade Federal do Parana - Departamento de Engenharia Mecanica, PR (Brazil); Amico, S.C. [Universidade Federal do Rio Grande do Sul - Departamento de Materiais, RS (Brazil)

    2010-07-01

    The electrode/membrane system, called MEA, is the fundamental unit of a PEMFC (proton exchange membrane fuel cell). Within the MEA, the gas diffusion layer (GDL) is the bridge between the flow field and the catalyst layer. One of the important elements in a GDL is the substrate, typically a carbon cloth or paper, that has to be an excellent electrical conductor and show mechanical strength along with thermal and chemical stability. In this work, GDLs were produced from a suspension containing short carbon fibers in water-based polyurethane and poly(vinyl alcohol) (PVA) resins with appropriate characteristics to be used in low temperature fuel cells. The obtained GDL was characterized regarding its wettability, electrical conductivity and morphological aspects, evaluated by SEM. (author)

  17. Evaluation of stainless steel cathodes and a bicarbonate buffer for hydrogen production in microbial electrolysis cells using a new method for measuring gas production

    KAUST Repository

    Ambler, Jack R.; Logan, Bruce E.

    2011-01-01

    Microbial electrolysis cells (MECs) are often examined for hydrogen production using non-sustainable phosphate buffered solutions (PBS), although carbonate buffers have been shown to work in other bioelectrochemical systems with a platinum (Pt) catalyst. Stainless steel (SS) has been shown to be an effective catalyst for hydrogen evolution in MECs, but it has not been tested with carbonate buffers. We evaluated the combined using of SS cathodes and a bicarbonate buffer (BBS) at the applied voltages of 0.5, 0.7 and 0.9 V using a new inexpensive method for measuring gas production called the gas bag method (GBM). This method achieved an average error of only 5.0% based on adding known volumes of gas to the bag. Using the GBM, hydrogen production with SS and a BBS was 26.6 ± 1.8 mL which compared well to 26.4 ± 2.8 mL using Pt and BBS, and 26.8 ± 2.5 mL with a Pt cathode and PBS. Electrical energy efficiency was highest with a SS cathode and BBS at 159 ± 17%, compared to 126 ± 14% for the Pt cathode and BBS, and 134 ± 17% for a Pt cathode and PBS. The main disadvantage of the SS was a lower gas production rate of 1.1 ± 0.3 m3 H2-m-3 d-1 with BBS and 1.2 ± 0.3 m3 H2-m-3 d -1 with PBS, compared to 1.7 ± 0.4 m3 H 2-m-3 d-1 with Pt and PBS. These results show that the GBM is an effective new method for measuring gas production of anaerobic gas production processes, and that SS and bicarbonate buffers can be used to effectively produce hydrogen in MECs. © 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.

  18. FFTF gas processing systems

    International Nuclear Information System (INIS)

    Halverson, T.G.

    1977-01-01

    The design and operation of the two radioactive gas processing systems at the Fast Flux Test Facility (FFTF) exemplifies the concept that will be used in the first generation of Liquid Metal Fast Breeder Reactors (LMFBR's). The two systems, the Radioactive Argon Processing System (RAPS) and the Cell Atmosphere Processing System (CAPS), process the argon and nitrogen used in the FFTF for cover gas on liquid metal systems and as inert atmospheres in steel lined cells housing sodium equipment. The RAPS specifically processes the argon cover gas from the reactor coolant system, providing for decontamination and eventual reuse. The CAPS processes radioactive gasses from inerted cells and other liquid metal cover gas systems, providing for decontamination and ultimate discharge to the atmosphere. The cryogenic processing of waste gas by both systems is described

  19. DETECTION OF MERCURIC BROMIDE IN A GAS PHASE FLOW CELL BY LASER PHOTOFRAGMENT FLUORESCENCE SPECTROSCOPY. (R825380)

    Science.gov (United States)

    Photofragment fluorescence (PFF) spectroscopy offers real-time monitoring capability with high-analytical sensitivity and selectivity for volatile mercury compounds found in process gas streams, such as incinerator stacks. In this work, low concentrations (6 ppb to...

  20. Human plasmacytoid dentritic cells elicit a Type I Interferon response by sensing DNA via the cGAS-STING signaling pathway.

    Science.gov (United States)

    Bode, Christian; Fox, Mario; Tewary, Poonam; Steinhagen, Almut; Ellerkmann, Richard K; Klinman, Dennis; Baumgarten, Georg; Hornung, Veit; Steinhagen, Folkert

    2016-07-01

    Plasmacytoid dendritic cells (pDCs) are a major source of type I interferon (IFN) and are important for host defense by sensing microbial DNA via TLR9. pDCs also play a critical role in the pathogenesis of IFN-driven autoimmune diseases. Yet, this autoimmune reaction is caused by the recognition of self-DNA and has been linked to TLR9-independent pathways. Increasing evidence suggests that the cytosolic DNA receptor cyclic GMP-AMP (cGAMP) synthase (cGAS) is a critical component in the detection of pathogens and contributes to autoimmune diseases. It has been shown that binding of DNA to cGAS results in the synthesis of cGAMP and the subsequent activation of the stimulator of interferon genes (STING) adaptor to induce IFNs. Our results show that the cGAS-STING pathway is expressed and activated in human pDCs by cytosolic DNA leading to a robust type I IFN response. Direct activation of STING by cyclic dinucleotides including cGAMP also activated pDCs and knockdown of STING abolished this IFN response. These results suggest that pDCs sense cytosolic DNA and cyclic dinucleotides via the cGAS-STING pathway and that targeting this pathway could be of therapeutic interest. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Compressed gas fuel storage system

    Science.gov (United States)

    Wozniak, John J.; Tiller, Dale B.; Wienhold, Paul D.; Hildebrand, Richard J.

    2001-01-01

    A compressed gas vehicle fuel storage system comprised of a plurality of compressed gas pressure cells supported by shock-absorbing foam positioned within a shape-conforming container. The container is dimensioned relative to the compressed gas pressure cells whereby a radial air gap surrounds each compressed gas pressure cell. The radial air gap allows pressure-induced expansion of the pressure cells without resulting in the application of pressure to adjacent pressure cells or physical pressure to the container. The pressure cells are interconnected by a gas control assembly including a thermally activated pressure relief device, a manual safety shut-off valve, and means for connecting the fuel storage system to a vehicle power source and a refueling adapter. The gas control assembly is enclosed by a protective cover attached to the container. The system is attached to the vehicle with straps to enable the chassis to deform as intended in a high-speed collision.

  2. Mathematical modeling of synthesis gas fueled electrochemistry and transport including H2/CO co-oxidation and surface diffusion in solid oxide fuel cell

    Science.gov (United States)

    Bao, Cheng; Jiang, Zeyi; Zhang, Xinxin

    2015-10-01

    Fuel flexibility is a significant advantage of solid oxide fuel cell (SOFC). A comprehensive macroscopic framework is proposed for synthesis gas (syngas) fueled electrochemistry and transport in SOFC anode with two main novelties, i.e. analytical H2/CO electrochemical co-oxidation, and correction of gas species concentration at triple phase boundary considering competitive absorption and surface diffusion. Staring from analytical approximation of the decoupled charge and mass transfer, we present analytical solutions of two defined variables, i.e. hydrogen current fraction and enhancement factor. Giving explicit answer (rather than case-by-case numerical calculation) on how many percent of the current output contributed by H2 or CO and on how great the water gas shift reaction plays role on, this approach establishes at the first time an adaptive superposition mechanism of H2-fuel and CO-fuel electrochemistry for syngas fuel. Based on the diffusion equivalent circuit model, assuming series-connected resistances of surface diffusion and bulk diffusion, the model predicts well at high fuel utilization by keeping fixed porosity/tortuosity ratio. The model has been validated by experimental polarization behaviors in a wide range of operation on a button cell for H2-H2O-CO-CO2-N2 fuel systems. The framework could be helpful to narrow the gap between macro-scale and meso-scale SOFC modeling.

  3. Contribution to the understanding of ion-gas reactions in ICP-MS collision reaction cells: application to the resolution of isobaric and polyatomic interferences

    International Nuclear Information System (INIS)

    Quemet, A.

    2012-01-01

    Inductively Coupled Plasma Mass Spectrometry (ICP-MS) emerged as the most essential technique in inorganic analytical chemistry thanks to its numerous assets, particularly its flexibility, its sensitivity and its reproducibility. As part of the elementary and isotopic analysis of irradiated fuel and transmutation target, the analyst is faced with a complex mass spectrum, due to the presence of many radionuclides. ICP-MS can not differentiate ions with the same mass, which induces isobaric and polyatomic interferences when the ions at the same mass are different chemical species. Last generations of ICP-MS have introduced collision reaction cells. It can in situ reduce these isobaric or polyatomic interferences. The cell is a multipole (quadrupole, hexapole or octupole) device filled with a collision and/or reaction gas. The gas molecules collide or possibly react with the ion beam, which eliminates or reduces interferences. Such resolution of interferences is based on the difference of chemical behaviours between the analyte and the interfering species: the choice of the gas is crucial. A better understanding of the 'ion - gas' reaction should help choosing the reacting gases. Three ICP-MS, with the different cell geometries, were used for this study: Perkin Elmer Elan DRC e (quadrupole), Thermo Fischer X serie II (hexapole) and Agilent Technologies 7700x (octupole). The effects of the cell geometry on different experimental parameters and on the resolution of the 56 Fe + / 40 Ar 16 O + polyatomic interferences were examined to measure iron at trace or ultra-trace level. This preliminary study was applied to measure iron as impurities in uranium oxide, the method was then validated with a Certified Reference Material. The reactivities of transition metals (Zr, Ru, Pd, Ag, Cd, Sn), lanthanides (La, Ce, Nd, Sm, Eu, Gd, Dy, Er and Yb) and actinides (U, Np, Pu, Am and Cm), elements of interest in the nuclear field, are studied with numerous gases (O 2 , CO, CO 2 , N 2

  4. Simulation of thermal stresses in anode-supported solid oxide fuel cell stacks. Part II: Loss of gas-tightness, electrical contact and thermal buckling

    Science.gov (United States)

    Nakajo, Arata; Wuillemin, Zacharie; Van herle, Jan; Favrat, Daniel

    Structural stability issues in planar solid oxide fuel cells arise from the mismatch between the coefficients of thermal expansion of the components. The stress state at operating temperature is the superposition of several contributions, which differ depending on the component. First, the cells accumulate residual stresses due to the sintering phase during the manufacturing process. Further, the load applied during assembly of the stack to ensure electric contact and flatten the cells prevents a completely stress-free expansion of each component during the heat-up. Finally, thermal gradients cause additional stresses in operation. The temperature profile generated by a thermo-electrochemical model implemented in an equation-oriented process modelling tool (gPROMS) was imported into finite-element software (ABAQUS) to calculate the distribution of stress and contact pressure on all components of a standard solid oxide fuel cell repeat unit. The different layers of the cell in exception of the cathode, i.e. anode, electrolyte and compensating layer were considered in the analysis to account for the cell curvature. Both steady-state and dynamic simulations were performed, with an emphasis on the cycling of the electrical load. The study includes two different types of cell, operation under both thermal partial oxidation and internal steam-methane reforming and two different initial thicknesses of the air and fuel compressive sealing gaskets. The results generated by the models are presented in two papers: Part I focuses on cell cracking. In the present paper, Part II, the occurrences of loss of gas-tightness in the compressive gaskets and/or electrical contact in the gas diffusion layer were identified. In addition, the dependence on temperature of both coefficients of thermal expansion and Young's modulus of the metallic interconnect (MIC) were implemented in the finite-element model to compute the plastic deformation, while the possibilities of thermal buckling

  5. Modified vaccinia virus Ankara triggers type I IFN production in murine conventional dendritic cells via a cGAS/STING-mediated cytosolic DNA-sensing pathway.

    Directory of Open Access Journals (Sweden)

    Peihong Dai

    2014-04-01

    Full Text Available Modified vaccinia virus Ankara (MVA is an attenuated poxvirus that has been engineered as a vaccine against infectious agents and cancers. Our goal is to understand how MVA modulates innate immunity in dendritic cells (DCs, which can provide insights to vaccine design. In this study, using murine bone marrow-derived dendritic cells, we assessed type I interferon (IFN gene induction and protein secretion in response to MVA infection. We report that MVA infection elicits the production of type I IFN in murine conventional dendritic cells (cDCs, but not in plasmacytoid dendritic cells (pDCs. Transcription factors IRF3 (IFN regulatory factor 3 and IRF7, and the positive feedback loop mediated by IFNAR1 (IFN alpha/beta receptor 1, are required for the induction. MVA induction of type I IFN is fully dependent on STING (stimulator of IFN genes and the newly discovered cytosolic DNA sensor cGAS (cyclic guanosine monophosphate-adenosine monophosphate synthase. MVA infection of cDCs triggers phosphorylation of TBK1 (Tank-binding kinase 1 and IRF3, which is abolished in the absence of cGAS and STING. Furthermore, intravenous delivery of MVA induces type I IFN in wild-type mice, but not in mice lacking STING or IRF3. Treatment of cDCs with inhibitors of endosomal and lysosomal acidification or the lysosomal enzyme Cathepsin B attenuated MVA-induced type I IFN production, indicating that lysosomal enzymatic processing of virions is important for MVA sensing. Taken together, our results demonstrate a critical role of the cGAS/STING-mediated cytosolic DNA-sensing pathway for type I IFN induction in cDCs by MVA. We present evidence that vaccinia virulence factors E3 and N1 inhibit the activation of IRF3 and the induction of IFNB gene in MVA-infected cDCs.

  6. Surface modification of gas diffusion layers by inorganic nanomaterials for performance enhancement of proton exchange membrane fuel cells at low RH conditions

    Energy Technology Data Exchange (ETDEWEB)

    Cindrella, L. [Fuel Cell Research Lab, Engineering Technology Department, Arizona State University, 7001 E Williams Field Rd., Mesa, AZ 85212 (United States); Department of Chemistry, National Institute of Technology, Tiruchirappalli, Tamil Nadu 620015 (India); Kannan, A.M. [Fuel Cell Research Lab, Engineering Technology Department, Arizona State University, 7001 E Williams Field Rd., Mesa, AZ 85212 (United States); Ahmad, R.; Thommes, M. [Quantachrome Instruments, 1900 Corporate Drive, Boynton Beach, FL 33426 (United States)

    2009-08-15

    Prompted by our earlier study that fumed silica on gas diffusion layer (GDL) favored a performance improvement of the single fuel cell at lower RH conditions, the present study has been carried out with inorganic oxides in the nanoscale such as TiO{sub 2}, Al{sub 2}O{sub 3}, commercially available mixed oxides, hydrophilic silica and aerosil silica. The structure of each of the oxide coating on the GDL surface has resulted in refinement with graded pore dimension as seen from the Hg porosimetry data. The fuel cell evaluation at various RH conditions (50-100%) revealed that the performance of all the inorganic oxides loaded GDL is very high compared to that of pristine GDL. The results confirm our earlier observation that inorganic oxides on GDL bring about structural refinement favorable for the transport of gases, and their water retaining capacity enable a high performance of the fuel cell even at low RH conditions. (author)

  7. S/sub N/ computational benchmark solutions for slab geometry models of a gas-cooled fast reactor (GCFR) lattice cell

    International Nuclear Information System (INIS)

    McCoy, D.R.

    1981-01-01

    S/sub N/ computational benchmark solutions are generated for a onegroup and multigroup fuel-void slab lattice cell which is a rough model of a gas-cooled fast reactor (GCFR) lattice cell. The reactivity induced by the extrusion of the fuel material into the voided region is determined for a series of partially extruded lattice cell configurations. A special modified Gauss S/sub N/ ordinate array design is developed in order to obtain eigenvalues with errors less than 0.03% in all of the configurations that are considered. The modified Gauss S/sub N/ ordinate array design has a substantially improved eigenvalue angular convergence behavior when compared to existing S/sub N/ ordinate array designs used in neutron streaming applications. The angular refinement computations are performed in some cases by using a perturbation theory method which enables one to obtain high order S/sub N/ eigenvalue estimates for greatly reduced computational costs

  8. THERMODYNAMIC MODEL OF GAS HYDRATES

    OpenAIRE

    Недоступ, В. И.; Недоступ, О. В.

    2015-01-01

    The interest to gas hydrates grows last years. Therefore working out of reliable settlement-theoretical methods of definition of their properties is necessary. The thermodynamic model of gas hydrates in which the central place occupies a behaviour of guest molecule in cell is described. The equations of interaction of molecule hydrate formative gas with cell are received, and also an enthalpy and energy of output of molecule from a cell are determined. The equation for calculation of thermody...

  9. The effect of carrier gas flow rate and source cell temperature on low pressure organic vapor phase deposition simulation by direct simulation Monte Carlo method

    Science.gov (United States)

    Wada, Takao; Ueda, Noriaki

    2013-01-01

    The process of low pressure organic vapor phase deposition (LP-OVPD) controls the growth of amorphous organic thin films, where the source gases (Alq3 molecule, etc.) are introduced into a hot wall reactor via an injection barrel using an inert carrier gas (N2 molecule). It is possible to control well the following substrate properties such as dopant concentration, deposition rate, and thickness uniformity of the thin film. In this paper, we present LP-OVPD simulation results using direct simulation Monte Carlo-Neutrals (Particle-PLUS neutral module) which is commercial software adopting direct simulation Monte Carlo method. By estimating properly the evaporation rate with experimental vaporization enthalpies, the calculated deposition rates on the substrate agree well with the experimental results that depend on carrier gas flow rate and source cell temperature. PMID:23674843

  10. The effect of carrier gas flow rate and source cell temperature on low pressure organic vapor phase deposition simulation by direct simulation Monte Carlo method

    Science.gov (United States)

    Wada, Takao; Ueda, Noriaki

    2013-04-01

    The process of low pressure organic vapor phase deposition (LP-OVPD) controls the growth of amorphous organic thin films, where the source gases (Alq3 molecule, etc.) are introduced into a hot wall reactor via an injection barrel using an inert carrier gas (N2 molecule). It is possible to control well the following substrate properties such as dopant concentration, deposition rate, and thickness uniformity of the thin film. In this paper, we present LP-OVPD simulation results using direct simulation Monte Carlo-Neutrals (Particle-PLUS neutral module) which is commercial software adopting direct simulation Monte Carlo method. By estimating properly the evaporation rate with experimental vaporization enthalpies, the calculated deposition rates on the substrate agree well with the experimental results that depend on carrier gas flow rate and source cell temperature.

  11. Simultaneous Photoacoustic and Photopyroelectric Detection of Trace Gas Emissions from Some Plant Parts and Their Related Essential Oils in a Combined Detection Cell

    Science.gov (United States)

    Abu-Taha, M. I.; Abu-Teir, M. M.; Al-Jamal, A. J.; Eideh, H.

    The aim of this work was to establish the feasibility of the combined photoacoustic (PA) and photopyroelectric (PPE) detection of the vapours emitted from essential oils and their corresponding uncrushed leaves or flowers. Gas traces of jasmine (Jessamine (Jasminum)), mint (Mentha arvensis L.) and Damask rose (Rosa damascena Miller) and their essential oils were tested using a combined cell fitted with both a photopyroelectric film (PVDF) and a microphone in conjunction with a pulsed wideband infrared source (PWBS) source. Infrared PA and PPE absorbances were obtained simultaneously at room temperatures with excellent reproducibility and high signal-to-noise ratios. Significant similarities found between the PA and PPE spectra of the trace gas emissions of plant parts, i.e., flowers or leaves and their related essential oils show the good correlation of their emissions and that both effects are initiated by the same absorbing molecules.

  12. Gas-discharge plasma processes for surface modification and conversion of chemical substances. Application for fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, K.; Meyer, D.; Rohland, B.; Heintze, M.; Zahn, R.J.; Hannemann, M.; Meusinger, J.; Ohl, A. [Institute of Non-Thermal Plasma Physics, Greifswald (Germany)]|[Gesellschaft fuer Angewandte Technik mbH Greifswald (Germany)]|[GAPC, Adam Opel AG, IPC, Ruesselsheim (Germany)

    2001-07-01

    The potential of plasma processes towards hydrogen and fuel cell technology will be demonstrated by two examples with preliminary results: 1. plasma modification of polymer electrolyte membranes for direct methanol fuel cells, and 2. plasma supported steam reforming.

  13. Dimensionless numbers and correlating equations for the analysis of the membrane-gas diffusion electrode assembly in polymer electrolyte fuel cells

    Science.gov (United States)

    Gyenge, E. L.

    The Quraishi-Fahidy method [Can. J. Chem. Eng. 59 (1981) 563] was employed to derive characteristic dimensionless numbers for the membrane-electrolyte, cathode catalyst layer and gas diffuser, respectively, based on the model presented by Bernardi and Verbrugge for polymer electrolyte fuel cells [AIChE J. 37 (1991) 1151]. Monomial correlations among dimensionless numbers were developed and tested against experimental and mathematical modeling results. Dimensionless numbers comparing the bulk and surface-convective ionic conductivities, the electric and viscous forces and the current density and the fixed surface charges, were employed to describe the membrane ohmic drop and its non-linear dependence on current density due to membrane dehydration. The analysis of the catalyst layer yielded electrode kinetic equivalents of the second Damköhler number and Thiele modulus, influencing the penetration depth of the oxygen reduction front based on the pseudohomogeneous film model. The correlating equations for the catalyst layer could describe in a general analytical form, all the possible electrode polarization scenarios such as electrode kinetic control coupled or not with ionic and/or oxygen mass transport limitation. For the gas diffusion-backing layer correlations are presented in terms of the Nusselt number for mass transfer in electrochemical systems. The dimensionless number-based correlating equations for the membrane electrode assembly (MEA) could provide a practical approach to quantify single-cell polarization results obtained under a variety of experimental conditions and to implement them in models of the fuel cell stack.

  14. Dimensionless numbers and correlating equations for the analysis of the membrane-gas diffusion electrode assembly in polymer electrolyte fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Gyenge, E.L. [Department of Chemical and Biological Engineering, The University of British Columbia, 2216 Main Mall, Vancouver, BC (Canada V6T 1Z4)

    2005-12-01

    The Quraishi-Fahidy method [Can. J. Chem. Eng. 59 (1981) 563] was employed to derive characteristic dimensionless numbers for the membrane-electrolyte, cathode catalyst layer and gas diffuser, respectively, based on the model presented by Bernardi and Verbrugge for polymer electrolyte fuel cells [AIChE J. 37 (1991) 1151]. Monomial correlations among dimensionless numbers were developed and tested against experimental and mathematical modeling results. Dimensionless numbers comparing the bulk and surface-convective ionic conductivities, the electric and viscous forces and the current density and the fixed surface charges, were employed to describe the membrane ohmic drop and its non-linear dependence on current density due to membrane dehydration. The analysis of the catalyst layer yielded electrode kinetic equivalents of the second Damkohler number and Thiele modulus, influencing the penetration depth of the oxygen reduction front based on the pseudohomogeneous film model. The correlating equations for the catalyst layer could describe in a general analytical form, all the possible electrode polarization scenarios such as electrode kinetic control coupled or not with ionic and/or oxygen mass transport limitation. For the gas diffusion-backing layer correlations are presented in terms of the Nusselt number for mass transfer in electrochemical systems. The dimensionless number-based correlating equations for the membrane electrode assembly (MEA) could provide a practical approach to quantify single-cell polarization results obtained under a variety of experimental conditions and to implement them in models of the fuel cell stack. (author)

  15. Gas hydrate nucleation

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-31

    The overall aim of the project was to gain more knowledge about the kinetics of gas hydrate formation especially the early growth phase. Knowledge of kinetics of gas hydrate formation is important and measurements of gas hydrate particle size and concentration can contribute to improve this knowledge. An experimental setup for carrying out experimental studies of the nucleation and growth of gas hydrates has been constructed and tested. Multi wavelength extinction (MWE) was the experimental technique selected for obtaining particle diameter and concentration. The principle behind MWE is described as well as turbidity spectrum analysis that in an initial stage of the project was considered as an alternative experimental technique. Details of the experimental setup and its operation are outlined. The measuring cell consists of a 1 litre horizontal tube sustaining pressures up to 200 bar. Laser light for particle size determination can be applied through sapphire windows. A description of the various auxiliary equipment and of another gas hydrate cell used in the study are given. A computer program for simulation and analysis of gas hydrate experiments is based on the gas hydrate kinetics model proposed by Skovborg and Rasmussen (1993). Initial measurements showed that knowledge of the refractive index of gas hydrates was important in order to use MWE. An experimental determination of the refractive index of methane and natural gas hydrate is described. The test experiments performed with MWE on collectives of gas hydrate particles and experiments with ethane, methane and natural gas hydrate are discussed. Gas hydrate particles initially seem to grow mainly in size and at latter stages in number. (EG) EFP-94; 41 refs.

  16. Gas hydrate nucleation

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-12-31

    The overall aim of the project was to gain more knowledge about the kinetics of gas hydrate formation especially the early growth phase. Knowledge of kinetics of gas hydrate formation is important and measurements of gas hydrate particle size and concentration can contribute to improve this knowledge. An experimental setup for carrying out experimental studies of the nucleation and growth of gas hydrates has been constructed and tested. Multi wavelength extinction (MWE) was the experimental technique selected for obtaining particle diameter and concentration. The principle behind MWE is described as well as turbidity spectrum analysis that in an initial stage of the project was considered as an alternative experimental technique. Details of the experimental setup and its operation are outlined. The measuring cell consists of a 1 litre horizontal tube sustaining pressures up to 200 bar. Laser light for particle size determination can be applied through sapphire windows. A description of the various auxiliary equipment and of another gas hydrate cell used in the study are given. A computer program for simulation and analysis of gas hydrate experiments is based on the gas hydrate kinetics model proposed by Skovborg and Rasmussen (1993). Initial measurements showed that knowledge of the refractive index of gas hydrates was important in order to use MWE. An experimental determination of the refractive index of methane and natural gas hydrate is described. The test experiments performed with MWE on collectives of gas hydrate particles and experiments with ethane, methane and natural gas hydrate are discussed. Gas hydrate particles initially seem to grow mainly in size and at latter stages in number. (EG) EFP-94; 41 refs.

  17. Fuzzy-based failure mode and effect analysis (FMEA) of a hybrid molten carbonate fuel cell (MCFC) and gas turbine system for marine propulsion

    Science.gov (United States)

    Ahn, Junkeon; Noh, Yeelyong; Park, Sung Ho; Choi, Byung Il; Chang, Daejun

    2017-10-01

    This study proposes a fuzzy-based FMEA (failure mode and effect analysis) for a hybrid molten carbonate fuel cell and gas turbine system for liquefied hydrogen tankers. An FMEA-based regulatory framework is adopted to analyze the non-conventional propulsion system and to understand the risk picture of the system. Since the participants of the FMEA rely on their subjective and qualitative experiences, the conventional FMEA used for identifying failures that affect system performance inevitably involves inherent uncertainties. A fuzzy-based FMEA is introduced to express such uncertainties appropriately and to provide flexible access to a risk picture for a new system using fuzzy modeling. The hybrid system has 35 components and has 70 potential failure modes, respectively. Significant failure modes occur in the fuel cell stack and rotary machine. The fuzzy risk priority number is used to validate the crisp risk priority number in the FMEA.

  18. Analysis of Mammalian Cell Proliferation and Macromolecule Synthesis Using Deuterated Water and Gas Chromatography-Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Victoria C. Foletta

    2016-10-01

    Full Text Available Deuterated water (2H2O, a stable isotopic tracer, provides a convenient and reliable way to label multiple cellular biomass components (macromolecules, thus permitting the calculation of their synthesis rates. Here, we have combined 2H2O labelling, GC-MS analysis and a novel cell fractionation method to extract multiple biomass components (DNA, protein and lipids from the one biological sample, thus permitting the simultaneous measurement of DNA (cell proliferation, protein and lipid synthesis rates. We have used this approach to characterize the turnover rates and metabolism of a panel of mammalian cells in vitro (muscle C2C12 and colon cancer cell lines. Our data show that in actively-proliferating cells, biomass synthesis rates are strongly linked to the rate of cell division. Furthermore, in both proliferating and non-proliferating cells, it is the lipid pool that undergoes the most rapid turnover when compared to DNA and protein. Finally, our data in human colon cancer cell lines reveal a marked heterogeneity in the reliance on the de novo lipogenic pathway, with the cells being dependent on both ‘self-made’ and exogenously-derived fatty acid.

  19. Influence of cathode flow pulsation on performance of proton exchange membrane fuel cell with interdigitated gas distributors

    International Nuclear Information System (INIS)

    Ramiar, A.; Mahmoudi, A.H.; Esmaili, Q.; Abdollahzadeh, M.

    2016-01-01

    In this paper, a numerical study is conducted in order to investigate the effect of pulsation of air flow at the cathode side of Proton Exchange Membrane (PEM) fuel cell with interdigitated flow field. A two dimensional, isothermal, two-phase, unsteady multi-component transport model is used in order to simulate the transport phenomena. The obtained results are discussed in terms of the influence of flow pulsation on water management and cell performance. The results prove the effectiveness of flow pulsation on improving water removal from cell, enhancing reactants transports to the reaction sites, and increasing the cell performance expressed by increment in the cell limiting current density and maximum output power. The effects of pulsation frequency (f), amplitude (Amp), and mean inlet pressure (P_i_n) on the performance and the output power of the cell, are also investigated. The performance of the cell has no dependency on the frequency range considered in this study. However, as the pulsation amplitude increases the increment in the cell performance is more obvious. Moreover, applying flow pulsation at low flow rates leads to higher efficiency in water removal and performance enhancement. - Highlights: • Mechanism of water and oxygen transport under flow pulsation are discussed. • Pulsating cathode flow increases the limiting current density and output power. • The performance of cell has no significant dependency on pulsation frequency. • The performance and output power increase with the pulsation amplitude. • Using pulsating flow at lower average pressures leads to higher water removal rate.

  20. Natural gas

    Energy Technology Data Exchange (ETDEWEB)

    Fraser, J W

    1967-08-01

    This report on the natural gas industry of Canada includes: composition and uses of natural gas, production statistics, exploration and development, reserve estimates, natural gas processing, transportation, and marketing. For the Canadian natural gas industry, 1966 was a year of moderate expansion in all phases, with a strong demand continuing for sulfur and liquid hydrocarbons produced as by-products of gas processing. Value of natural gas production increased to $199 million and ranked sixth in terms of value of mineral ouput in Canada. Currently, natural gas provides over 70% of Canada's energy requirements. Proved remaining marketable reserves are estimated to be in excess of a 29-yr supply.

  1. Gas Sensor

    KAUST Repository

    Luebke, Ryan

    2015-01-22

    A gas sensor using a metal organic framework material can be fully integrated with related circuitry on a single substrate. In an on-chip application, the gas sensor can result in an area-efficient fully integrated gas sensor solution. In one aspect, a gas sensor can include a first gas sensing region including a first pair of electrodes, and a first gas sensitive material proximate to the first pair of electrodes, wherein the first gas sensitive material includes a first metal organic framework material.

  2. Gas Sensor

    KAUST Repository

    Luebke, Ryan; Eddaoudi, Mohamed; Omran, Hesham; Belmabkhout, Youssef; Shekhah, Osama; Salama, Khaled N.

    2015-01-01

    A gas sensor using a metal organic framework material can be fully integrated with related circuitry on a single substrate. In an on-chip application, the gas sensor can result in an area-efficient fully integrated gas sensor solution. In one aspect, a gas sensor can include a first gas sensing region including a first pair of electrodes, and a first gas sensitive material proximate to the first pair of electrodes, wherein the first gas sensitive material includes a first metal organic framework material.

  3. Quasi-three dimensional dynamic modeling of a proton exchange membrane fuel cell with consideration of two-phase water transport through a gas diffusion layer

    International Nuclear Information System (INIS)

    Kang, Sanggyu

    2015-01-01

    Water management is one of the challenging issues for low-temperature PEMFCs (proton exchange membrane fuel cells). When liquid water is formed at the GDL (gas diffusion layer), the pathway of reactant gas can be blocked, which inhibits the electrochemical reaction of PEMFC. Thus, liquid water transport through GDL is a critical factor determining the performance of a PEMFC. In present study, quasi-three dimensional dynamic modeling of PEMFC with consideration of two-phase water transport through GDL is developed. To investigate the distributions of PEMFC characteristics, including current density, species mole fraction, and membrane hydration, the PEMFC was discretized into twenty control volumes along the anode channel. To resolve the mass and energy conservation, the PEMFC is discretized into eleven and fifteen control volumes in the perpendicular direction, respectively. The dynamic variation of PEMFC characteristics of cell voltage, overvoltage of activation and ohmic, liquid water saturation through a GDL, and oxygen concentration were captured during transient behavior. - Highlights: • A quasi-three dimensional two-phase dynamic model of PEMFC is developed. • Presented model is validated by comparison with experimental data. • Two-phase model is compared with one-phase model at steady-states and transients.

  4. Facile and Scalable Fabrication of Highly Efficient Lead Iodide Perovskite Thin-Film Solar Cells in Air Using Gas Pump Method.

    Science.gov (United States)

    Ding, Bin; Gao, Lili; Liang, Lusheng; Chu, Qianqian; Song, Xiaoxuan; Li, Yan; Yang, Guanjun; Fan, Bin; Wang, Mingkui; Li, Chengxin; Li, Changjiu

    2016-08-10

    Control of the perovskite film formation process to produce high-quality organic-inorganic metal halide perovskite thin films with uniform morphology, high surface coverage, and minimum pinholes is of great importance to highly efficient solar cells. Herein, we report on large-area light-absorbing perovskite films fabrication with a new facile and scalable gas pump method. By decreasing the total pressure in the evaporation environment, the gas pump method can significantly enhance the solvent evaporation rate by 8 times faster and thereby produce an extremely dense, uniform, and full-coverage perovskite thin film. The resulting planar perovskite solar cells can achieve an impressive power conversion efficiency up to 19.00% with an average efficiency of 17.38 ± 0.70% for 32 devices with an area of 5 × 2 mm, 13.91% for devices with a large area up to 1.13 cm(2). The perovskite films can be easily fabricated in air conditions with a relative humidity of 45-55%, which definitely has a promising prospect in industrial application of large-area perovskite solar panels.

  5. Process integration and optimization of a solid oxide fuel cellGas turbine hybrid cycle fueled with hydrothermally gasified waste biomass

    International Nuclear Information System (INIS)

    Facchinetti, Emanuele; Gassner, Martin; D’Amelio, Matilde; Marechal, François; Favrat, Daniel

    2012-01-01

    Due to its suitability for using wet biomass, hydrothermal gasification is a promising process for the valorization of otherwise unused waste biomass to synthesis gas and biofuels. Solid oxide fuel cell (SOFC) based hybrid cycles are considered as the best candidate for a more efficient and clean conversion of (bio) fuels. A significant potential for the integration of the two technologies is expected since hydrothermal gasification requires heat at 673–773 K, whereas SOFC is characterized by heat excess at high temperature due to the limited electrochemical fuel conversion. This work presents a systematic process integration and optimization of a SOFC-gas turbine (GT) hybrid cycle fueled with hydrothermally gasified waste biomass. Several design options are systematically developed and compared through a thermodynamic optimization approach based on First Law and exergy analysis. The work demonstrates the considerable potential of the system that allows for converting wet waste biomass into electricity at a First Law efficiency of up to 63%, while simultaneously enabling the separation of biogenic carbon dioxide for further use or sequestration. -- Highlights: ► Hydrothermal gasification is a promising process for the valorization of waste wet biomass. ► Solid Oxide Fuel CellGas Turbine hybrid cycle emerges as the best candidates for conversion of biofuels. ► A systematic process integration and optimization of a SOFC-GT hybrid cycle fuelled with hydrothermally gasified biomass is presented. ► The system may convert wet waste biomass to electricity at a First Law efficiency of 63% while separating the biogenic carbon dioxide. ► The process integration enables to improve the First Law efficiency of around 4% with respect to a non-integrated system.

  6. Gas manufacture

    Energy Technology Data Exchange (ETDEWEB)

    Fell, J W

    1915-05-03

    Retorts for the distillation of shale or coal for the production of oil or illuminating-gas are heated by gas from a generator or a gas-holder, and a portion of the gas from the flue leading to the heating-flues is forced by a steam jet through a by-pass and is injected into the bottom of the retorts. If the gas to be admitted to the retort is cold, it is first heated.

  7. Natural Gas

    OpenAIRE

    Bakar, Wan Azelee Wan Abu; Ali, Rusmidah

    2010-01-01

    Natural gas fuel is a green fuel and becoming very demanding because it is environmental safe and clean. Furthermore, this fuel emits lower levels of potentially harmful by-products into the atmosphere. Most of the explored crude natural gas is of sour gas and yet, very viable and cost effective technology is still need to be developed. Above all, methanation technology is considered a future potential treatment method for converting the sour natural gas to sweet natural gas.

  8. Mustard Gas Surrogate, 2-Chloroethyl Ethylsulfide (2-CEES), Induces Centrosome Amplification and Aneuploidy in Human and Mouse Cells

    Science.gov (United States)

    2014-03-01

    increase in aneuploidy in treated  cells .      Methods and Materials    Cell   Culture     Saos2 (human  osteosarcoma ) and NIH3T3 (murine embryonic...fibroblasts)  cells  were obtained  from ATCC (HTB‐85 and CRL‐1658, respectively) and  cultured  in complete media:  Dulbecco’s  Modified Eagle Medium (DMEM...subconfluent  cultures .  After the 5 day incubation,  cells  were treated     with 0.5 μg/ml colcemid (Gibco) for 4 hours.   Cell  media was harvested and retained

  9. Surface modification of porous nanocrystalline TiO2 films for dye-sensitized solar cell application by various gas plasmas

    International Nuclear Information System (INIS)

    Kim, Youngsoo; Yoon, Chang-Ho; Kim, Kang-Jin; Lee, Yeonhee

    2007-01-01

    Titanium dioxide (TiO 2 ) film for dye-sensitized solar cells (DSSCs) has surface defects such as oxygen vacancies created during the annealing process. The authors used a plasma treatment technique to reduce defects on TiO 2 surfaces. They investigated the influence of different gas plasma treatments of TiO 2 film on the photoelectric performance of DSSC. Short-circuit photocurrent density (J sc ), open-circuit photovoltage (V oc ), and the amount of adsorbed dye for DSSCs were measured. As a result, the solar-to-electricity conversion efficiencies of the O 2 - and N 2 -treated cells increased by 15%-20% compared to untreated cells. On the other hand, solar energy conversion efficiency of CF 4 -plasma treated cells decreased drastically. The increased amount of adsorbed dye on the TiO 2 film was measured by time-of-flight secondary ion mass spectrometry. TiO 2 surfaces modified by plasma treatment were characterized using analytical instruments such as x-ray photoelectron spectroscopy and near-edge x-ray absorption fine structure

  10. An integrated high temperature environmental cell for atom probe tomography studies of gas-surface reactions: Instrumentation and results

    International Nuclear Information System (INIS)

    Dumpala, S.; Broderick, S.R.; Bagot, P.A.J.; Rajan, K.

    2014-01-01

    An integrated environmental cell has been designed and developed for the latest generation of Atom Probe Tomography LEAP™ instruments, allowing controlled exposure of samples to gases at high temperatures. Following treatment, samples can be transferred through the LEAP vacuum system for subsequent APT analysis, which provides detailed information on changes to chemical microstructures following the reactions with near-atomic resolution. A full description of the cell is presented, along with some sample results on the oxidation of aluminum and two platinum-group alloys, demonstrating the capability of combining exposure/characterization functionality in a single instrument. - Highlights: • Designed and built atom probe environmental cell for in situ reactions. • Investigated Al oxidation, and demonstrated improvement with new cell. • in situ APT analysis of Pt-alloys showed surface segregation of Rh and Ir

  11. Development and Characterization of Gas Diffusion Layer Using Carbon Slurry Dispersed by Ammonium Lauryl Sulfate for Proton Exchange Member Fuel Cells

    Science.gov (United States)

    Villacorta, Rashida

    Gas diffusion layers (GDLs) are a critical and essential part of proton exchange membrane fuel cells (PEMFCs). They carry out various important functions such as transportation of reactants to and from the reaction sites. The material properties and structural characteristics of the substrate and the microporous layer strongly influence fuel cell performance. The microporous layer of the GDLs was fabricated with the carbon slurry dispersed in water containing ammonium lauryl sulfate (ALS) using the wire rod coating method. GDLs were fabricated with different materials to compose the microporous layer and evaluated the effects on PEMFC power output performance. The consistency of the carbon slurry was achieved by adding 25 wt. % of PTFE, a binding agent with a 75:25 ratio of carbon (Pureblack and vapor grown carbon fiber). The GDLs were investigated in PEMFC under various relative humidity (RH) conditions using H2/O2 and H2/Air. GDLs were also fabricated with the carbon slurry dispersed in water containing sodium dodecyl sulfate (SDS) and multiwalled carbon nanotubes (MWCNTs) with isopropyl alcohol (IPA) based for fuel cell performance comparison. MWCNTs and SDS exhibits the highest performance at 60% and 70% RH with a peak power density of 1100 mW.cm-2 and 850 mW.cm-2 using air and oxygen as an oxidant. This means that the gas diffusion characteristics of these two samples were optimum at 60 and 70 % RH with high limiting current density range. It was also found that the composition of the carbon slurry, specifically ALS concentration has the highest peak power density of 1300 and 500mW.cm-2 for both H2/O 2 and H2/Air at 100% RH. However, SDS and MWCNTs demonstrates the lowest power density using air and oxygen as an oxidants at 100% RH.

  12. Optimisation of the process of fuel gas production for fuel cells in motor vehicles; Verfahrenstechnische Optimierung der Brenngaserzeugung fuer Brennstoffzellen in Kraftfahrzeugen

    Energy Technology Data Exchange (ETDEWEB)

    Colsman, G

    1995-10-01

    There are advanced development programs and demonstration projects worldwide concerning the use of Proton Exchange Membrane Fuel Cells (PEMFC) in passenger cars. The on-board production of a hydrogen-rich fuel gas in particular requires research and development. Based on a comparison of different energy carriers and hydrogen production processes, the methanol steam-reforming system is optimized with respect to criteria such as power density and fuel gas quality. The specific hydrogen production is thereby raised to 10 m{sup 3} (STP) per hour and litre of catalyst at 99.5% methanol conversion rate and 280 C reformer wall temperature. Due to the fact, that the maximum CO concentration in the fuel gas, which is tolerable by the PEMFC with platinum catalyst, is 10 ppm, a separate gas cleaning is necessary after the steam reforming process. Different gas treatment processes are discussed and investigated theoretically as well as experimentally. Pore-free metal membranes allow the separation of ultra pure (>99.9999 vol.-%) hydrogen from the reformer gas while the technical criteria for the use in passenger cars are fulfilled. The investigations are completed by mathematical models of the optimized methanol reformer as well as the gas separation by membranes. The results of this work concerning the optimization of the fuel processing from methanol have made possible the building and testing of a fuel gas production unit on a passenger car scale. Volume and weight of the total unit allow already today the installation in a vehicle without any restrictions. (orig.) [Deutsch] Der Einsatz von PEMFC (Brennstoffzellen mit Protonenaustauschmembran) in Kraftfahrzeugen wird weltweit erforscht und in zahlreichen Prototypen demonstriert. Insbesondere auf dem Gebiet der Erzeugung eines wasserstoffreichen Brenngases im Kraftfahrzeug besteht ein erheblicher Entwicklungsbedarf. Auf der Basis eines Vergleichs verschiedener Energietraeger und Verfahren der Wasserstoffgewinnung wird das

  13. Lattice Boltzmann simulations of water transport in gas diffusion layer of a polymer electrolyte membrane fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Liang; Cheng, Ping [Ministry of Education Key Laboratory of Power Machinery and Engineering, School of Mechanical Engineering, Shanghai Jiaotong University, DongChuan Road 800, Shanghai 200240 (China)

    2010-06-15

    The effect of wettability on water transport dynamics in gas diffusion layer (GDL) is investigated by simulating water invasion in an initially gas-filled GDL using the multiphase free-energy lattice Boltzmann method (LBM). The results show that wettability plays a significant role on water saturation distribution in two-phase flow in the uniform wetting GDL. For highly hydrophobicity, the water transport falls in the regime of capillary fingering, while for neutral wettability, water transport exhibits the characteristic of stable displacement, although both processes are capillary force dominated flow with same capillary numbers. In addition, the introduction of hydrophilic paths in the GDL leads the water to flow through the hydrophilic pores preferentially. The resulting water saturation distributions show that the saturation in the GDL has little change after water breaks through the GDL, and further confirm that the selective introduction of hydrophilic passages in the GDL would facilitate the removal of liquid water more effectively, thus alleviating the flooding in catalyst layer (CL) and GDL. The LBM approach presented in this study provides an effective tool to investigate water transport phenomenon in the GDL at pore-scale level with wettability distribution taken into consideration. (author)

  14. Monocytopenia; Induction by Vinorelbine, Cisplatin and Doxorubicin in Breast, Non-Small Cell Lung and Cervix Cancer Patients

    Science.gov (United States)

    Nazir, Taha; Taha, Nida; Islam, Azahrul; Abraham, Suraj; Mahmood, Adeel; Mustafa, Mazhar

    2016-01-01

    Background The neoplasm is still a potential threat for breast, Non-Small Cell Lung (NSCL) and cervix cancer patients. Those gradually invade into other body organs, inducing complex pathological complications. Whereas, the anticancer drugs suppress the bone marrow, resulting serious hematological toxicities. Thus, the monocytic toxicity may the chance of infections, particularly in AID’s patients. Objective We aimed this retrospective study to investigate the monocytopenia induced by vinorelbine following chemotherapy in cancer patients. Patients and method A total 60 adult cancer patients were divided into two groups; Group-1 patients received the treatment of Vinorelbine alone while group 2 patients received Vinorelbine based combination chemotherapy. Result The overall comparison of mean monocyte count (×103 per μl) with time showed a significant statistical difference (p value <0.001) for G-I and no significant difference for G-II (p value <0.08). The independent comparison of mean values for two groups at every week confirms the non-significant statistical difference during all of the five weeks (p values 0.551, 0.112, 0.559, 0.372, 0.468 respectively). In addition of that, the comparison of mean values observed before therapy with that of week 4 (after therapy) showed significant difference in G-I (p value <0.001) and non-significant in G-II (p value 0.053). Conclusion Monocytopenia is induced in both of the chemotherapy protocols allows the clinical oncologists and consultant physicians to select either of the chemotherapy protocol. The therapeutic efficacy should constitute the intervening consideration to treat the breast, cervix and NSCL (Non-Small Cell Lung’s) cancers. PMID:27833519

  15. Progress on the data acquisition system at NSCL

    International Nuclear Information System (INIS)

    Fox, R.; Au, R.; Glynn, T.; Pollack, B.; Vander Mulen, A.

    1985-01-01

    We report on the progress made in data acquisition software development. Specifically, a unique generalized data routing scheme has been developed which allows user online analysis programs to be safely integrated into the acquisition system without endangering data sent to event recording devices. We describe the structure of the system. Performance is discussed and throughput calculated from it. User experience with the system is also discussed. We show how this routing system may easily be adapted to loosely coupled multiprocessor systems

  16. Use of Electrochemical Impedance Spectroscopy for the Evaluation of Performance of PEM Fuel Cells Based on Carbon Cloth Gas Diffusion Electrodes

    Directory of Open Access Journals (Sweden)

    Saverio Latorrata

    2018-01-01

    Full Text Available Polymer electrolyte membrane fuel cells (PEMFCs have attracted great attention in the last two decades as valuable alternative energy generators because of their high efficiencies and low or null pollutant emissions. In the present work, two gas diffusion electrodes (GDEs for PEMFCs were prepared by using an ink containing carbon-supported platinum in the catalytic phase which was sprayed onto a carbon cloth substrate. Two aerograph nozzles, with different sizes, were used. The prepared GDEs were assembled into a fuel cell lab prototype with commercial electrolyte and bipolar plates and tested alternately as anode and cathode. Polarization measurements and electrochemical impedance spectroscopy (EIS were performed on the running hydrogen-fed PEMFC from open circuit voltage to high current density. Experimental impedance spectra were fitted with an equivalent circuit model by using ZView software which allowed to get crucial parameters for the evaluation of fuel cell performance, such as ohmic resistance, charge transfer, and mass transfer resistance, whose trends have been studied as a function of the applied current density.

  17. An improved model for predicting electrical contact resistance between bipolar plate and gas diffusion layer in proton exchange membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Zhiliang; Wang, Shuxin [School of Mechanical Engineering, Tianjin University, Tianjin 300072 (China); Zhou, Yuanyuan; Lin, Guosong; Hu, S. Jack [Department of Mechanical Engineering, The University of Michigan, Ann Arbor, MI 48109-2125 (United States)

    2008-07-15

    Electrical contact resistance between bipolar plates (BPPs) and gas diffusion layers (GDLs) in PEM fuel cells has attracted much attention since it is one significant part of the total contact resistance which plays an important role in fuel cell performance. This paper extends a previous model by Zhou et al. [Y. Zhou, G. Lin, A.J. Shih, S.J. Hu, J. Power Sources 163 (2007) 777-783] on the prediction of electrical contact resistance within PEM fuel cells. The original microscale numerical model was based on the Hertz solution for individual elastic contacts, assuming that contact bodies, GDL carbon fibers and BPP asperities are isotropic elastic half-spaces. The new model features a more practical contact by taking into account the bending behavior of carbon fibers as well as their anisotropic properties. The microscale single contact process is solved numerically using the finite element method (FEM). The relationship between the contact pressure and the electrical resistance at the GDL/BPP interface is derived by multiple regression models. Comparisons of the original model by Zhou et al. and the new model with experimental data show that the original model slightly overestimates the electrical contact resistance, whereas a better agreement with experimental data is observed using the new model. (author)

  18. Water recovery and air humidification by condensing the moisture in the outlet gas of a proton exchange membrane fuel cell stack

    International Nuclear Information System (INIS)

    Wan, Z.M.; Wan, J.H.; Liu, J.; Tu, Z.K.; Pan, M.; Liu, Z.C.; Liu, W.

    2012-01-01

    Humidification is one of the most important factors for the operation of proton exchange membrane fuel cell (PEMFC). To maintain the membrane at hydrated state, plenty of water is needed for the state-of-the-art of PEMFC technology, especially in large power applications or long time operation. A condenser is introduced to separate liquid water from the air outlet for air self-sufficient in water of the stack in this study. The condensed temperature at the outlet of the condenser and water recovered amount for air self-sufficient in water are investigated theoretically and experimentally. It is shown that the condensed temperature for air self-sufficient in water is irrelevant with the working current of the stack. When the condenser outlet temperature was above the theoretical line, recovery water was not sufficient for the air humidification. On the contrary, it is sufficient while the temperature was below the theoretical line. It is also shown that when the moisture is sufficiently cooled, large amount water can be separated from the outlet gas, and it increased almost linearly with the time. With the introduction of the condenser, the recovered amount of water can easily satisfy the air self-sufficient in water by condensing the outlet gas to a proper temperature. - Highlights: ► We introduce a condenser to separate liquid water from the air outlet in the stack. ► The mechanism of air self-sufficient in water by condensing gas is presented. ► The condensed temperature and water recovered amount are investigated. ► An experiment is present to validate simplicity and feasibility of the criterion. ► The criterion for air humidification is used for choosing the condenser.

  19. Multi-objective optimization of a pressurized solid oxide fuel cell – gas turbine hybrid system integrated with seawater reverse osmosis

    International Nuclear Information System (INIS)

    Eveloy, Valerie; Rodgers, Peter; Al Alili, Ali

    2017-01-01

    To improve the capacity and efficiency of distributed power and fresh water generation in coastal industrial facilities affected by regional water scarcity, a natural gas-fueled, pressurized solid oxide fuel cell-gas turbine (SOFC-GT) hybrid is integrated with a bottoming organic Rankine cycle (ORC) and seawater reverse osmosis (RO) desalination plant. This power and water co-generation system is optimized in terms of two objectives, maximum exergy efficiency and minimum cost rate, using a genetic algorithm. The exergetic and economic performance of three solutions representing maximum exergy efficiency, minimum cost rate, and a compromise between efficiency and cost rate, are compared. When imposing a water production requirement (reference case), the selected compromise multi-objective optimization solution delivers a net power output of 2.4 MWe and 636 m"3/day of permeate, at a co-generation exergy efficiency and cost rate of 71.3% and 0.0256 USD/s, respectively. The system payback time is estimated to be less than six years for typical economic parameters, but would become unprofitable in the most unfavorable economic scenario considered. Overall, the results indicate the thermodynamic and economic benefits of reverse osmosis over thermal desalination processes for integration with high-efficiency power generation systems in coastal regions impacted by domestic gas shortages and water scarcity. - Highlights: • Integration of a pressurized SOFC-GT hybrid system with a reverse osmosis unit. • Multi-objective, exergetic and economic optimization using a genetic algorithm. • Optimum solution delivers 2.4 MWe and 636 m"3/day of desalinated water. • Overall exergy efficiency and cost rate of 71.3% and 0.0256 USD/s, respectively. • System payback time estimated at less than six years for typical economic conditions.

  20. Dry radon gas generator

    International Nuclear Information System (INIS)

    Vandrish, G.

    1979-10-01

    A radon gas standard with a source strength of 120037 pCi capable of delivering 121 pCi of radon gas successively to a large number of cells has been developed. The absolute source strength has been calibrated against two radium solution standards and is accurate to 4 percent. A large number of cells (approxiiately 50) may be calibrated conveniently on a daily basis with appropriate corrections for sequential changes in the amount of gas delivered, and a correction for the growth of radon in the standard on successive days. Daily calibration of ten cells or less does not require these corrections. The standard is suitable for field use and the source emanation rate is stable over extreme temperatue and pressure ranges and over six months

  1. A CNT (carbon nanotube) paper as cathode gas diffusion electrode for water management of passive μ-DMFC (micro-direct methanol fuel cell) with highly concentrated methanol

    International Nuclear Information System (INIS)

    Deng, Huichao; Zhang, Yufeng; Zheng, Xue; Li, Yang; Zhang, Xuelin; Liu, Xiaowei

    2015-01-01

    A novel MEA (membrane electrode assembly) structure of passive μ-DMFC (micro-direct methanol fuel cell) controls water management and decreases methanol crossover. The CNT (carbon nanotube) paper replacing CP (carbon paper) as GDL (gas diffusion paper) enhances water back diffusion which passively prevents flooding in the cathode and promotes low methanol crossover. Moreover, the unique structure of CNT paper can also enhance efficiency of oxygen mass transport and catalyst utilization. The passive μ-DMFC with CNT-MEA exhibits significantly higher performance than passive μ-DMFC with CP-MEA and can operate in high methanol concentration, showing the peak power density of 23.2 mW cm −2 . The energy efficiency and fuel utilization efficiency are obviously improved from 11.54% to 22.7% and 36.61%–49.34%, respectively, and the water transport coefficient is 0.47 which is lower than previously reported passive μ-DMFC with CP. - Highlights: • This novel GDL (gas diffusion layer) solves water management and methanol crossover. • This GDL creates a hydraulic pressure in the cathode increasing water back diffusion. • This GDL improves the electrical conductivity and activity of catalyst

  2. New Method for Super Hydrophobic Treatment of Gas Diffusion Layers for Proton Exchange Membrane Fuel Cells Using Electrochemical Reduction of Diazonium Salts.

    Science.gov (United States)

    Thomas, Yohann R J; Benayad, Anass; Schroder, Maxime; Morin, Arnaud; Pauchet, Joël

    2015-07-15

    The purpose of this article is to report a new method for the surface functionalization of commercially available gas diffusion layers (GDLs) by the electrochemical reduction of diazonium salt containing hydrophobic functional groups. The method results in superhydrophobic GDLs, over a large area, without pore blocking. An X-ray photoelectron spectroscopy study based on core level spectra and chemical mapping has demonstrated the successful grafting route, resulting in a homogeneous distribution of the covalently bonded hydrophobic molecules on the surface of the GDL fibers. The result was corroborated by contact angle measurement, showing similar hydrophobicity between the grafted and PTFE-modified GDLs. The electrochemically modified GDLs were tested in proton exchange membrane fuel cells under automotive, wet, and dry conditions and demonstrated improved performance over traditional GDLs.

  3. Water droplet dynamic behavior during removal from a proton exchange membrane fuel cell gas diffusion layer by Lattice-Boltzmann method

    Energy Technology Data Exchange (ETDEWEB)

    Molaeimanesh, Golamreza; Akbari, Mohammad Hadi [Shiraz University, Shiraz (Iran, Islamic Republic of)

    2014-04-15

    A major challenge in the application of proton exchange membrane fuel cells (PEMFCs) is water management, with the flooding of electrodes as the main issue. The Lattice-Boltzmann method (LBM) is a relatively new technique that is superior in modeling the dynamic interface of multiphase fluid flow in complex microstructures such as non-homogeneous and anisotropic porous media of PEMFC electrodes. In this study, the dynamic behavior of a water droplet during removal from gas diffusion layer (GDL) of a PEMFC electrode with interdigitated flow field is simulated using LBM. The effects of GDL wettability and its spanwise and transverse gradients on the removal process are investigated. The results demonstrate great influence of wettability and its spanwise and transverse gradients on the dynamic behavior of droplets during the removal process. Although increasing the hydrophobicity of GDL results in better droplet removal, its increase beyond a critical value does not show a significant effect.

  4. Determination of the extraction efficiency for {sup 233}U source α-recoil ions from the MLL buffer-gas stopping cell

    Energy Technology Data Exchange (ETDEWEB)

    Wense, Lars v.d.; Seiferle, Benedict; Thirolf, Peter G. [Ludwig-Maximilians-Universitaet Muenchen, Garching (Germany); Laatiaoui, Mustapha [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Helmholtz Institut Mainz, Mainz (Germany)

    2015-03-01

    Following the α decay of {sup 233}U, {sup 229}Th recoil ions are shown to be extracted in a significant amount from the MLL buffer-gas stopping cell. The produced recoil ions and subsequent daughter nuclei are mass purified with the help of a customized quadrupole mass spectrometer. The combined extraction and mass purification efficiency for {sup 229}Th{sup 3+} is determined via MCP-based measurements and via the direct detection of the {sup 229}Th α decay. A large value of (10±2)% for the combined extraction and mass purification efficiency of {sup 229}Th{sup 3+} is obtained at a mass resolution of about 1u/e. In addition to {sup 229}Th, also other α-recoil ions of the {sup 233,} {sup 232}U decay chains are addressed. (orig.)

  5. The Rn-222 with natural tracer in the study of natural gas transport within sterile cells of mining

    International Nuclear Information System (INIS)

    Chagas, Eduardo G.L. das; Dias, Danila C.S.; Guerrero, Eder T. Z.; Alberti, Heber L.C.; Couto, Jeferson A.; Silva, Nivaldo C.; Abreu, Carolina B.; Lopez, Dina; Branco, Otavio; Fleming, Peter M.

    2013-01-01

    The objectives of this work are mapping of Rn-222 concentration in the interstitial air of the cell 4 (BF-4) barren of uranium mining in the Industrias Nucleares do Brasil (INB), Pocos de Caldas, MG - Brazil, as well as build an automatic system for collection of interstitial gases

  6. Gas phase considerations for the deposition of thin film silicon solar cells by VHF-PECVD at low substrate temperatures

    NARCIS (Netherlands)

    Rath, J.K.; Verkerk, A.D.; Brinza, M.; Schropp, R.E.I.; Goedheer, W.J.; Krzhizhanovskaya, V.V.; Gorbachev, Y.E.; Orlov, K.E.; Khilkevitch, E.M.; Smirnov, A.S.

    2008-01-01

    Fabrication of thin film silicon solar cells on cheap plastics or paper-like substrate requires deposition process at very low substrate temperature, typically ≤ 100 °C. In a chemical vapor deposition process, low growth temperatures lead to materials with low density, high porosity, high disorder

  7. DEMONSTRATION OF FUEL CELLS TO RECOVER ENERGY FROM ANAEROBIC DIGESTER GAS - PHASE I. CONCEPTUAL DESIGN, PRELIMINARY COST, AND EVALUATION STUDY

    Science.gov (United States)

    The report discusses Phase I (a conceptual design, preliminary cost, and evaluation study) of a program to demonstrate the recovery of energy from waste methane produced by anaerobic digestion of waste water treatment sludge. The fuel cell is being used for this application becau...

  8. Greenhouse gas reduction and primary energy savings via adoption of a fuel cell hybrid plant in a hospital

    International Nuclear Information System (INIS)

    Bizzarri, Giacomo; Morini, Gian Luca

    2004-01-01

    The Kyoto agreement, expressing great concern about global climate change, has stated emissions of greenhouse gases, especially CO 2 from fossil fuel use, need to be reduced. According to this, existing plants have been required to cut emissions; moreover, there has been a greater emphasis on adopting efficient systems in order to reduce the energy losses. Among high efficiency technologies, fuel cells appear to be the most promising for their high efficiency and their very low environmental impact. This paper first reviews the state-of-the-art of fuel cells systems, then simulates the operation of a hybrid fuel cells plant in a 'typical hospital' analysing how it could optimize the hospitals energetic requirements. Hospitals and sanitary structures are normally characterized by considerable energy demands not often suitable with resolute energy retrofit strategies. Both the considerable primary energy savings and the pollutant emissions reduction, achieved upgrading conventional systems to a fuel cell hybrid plant, have the potential to prompt national boards to support their business development, as long as they achieve a consolidated market penetration

  9. Controls and measurements of KU engine test cells for biodiesel, SynGas, and assisted biodiesel combustion

    Science.gov (United States)

    Cecrle, Eric Daniel

    This thesis is comprised of three unique data acquisition and controls (CDAQ) projects. Each of these projects differs from each other; however, they all include the concept of testing renewable or future fuel sources. The projects were the following: University of Kansas's Feedstock-to-Tailpipe Initiative's Synthesis Gas Reforming rig, Feedstock-to-Tailpipe Initiative's Biodiesel Single Cylinder Test Stand, and a unique Reformate Assisted Biodiesel Combustion architecture. The main responsibility of the author was to implement, develop and test CDAQ systems for the projects. For the Synthesis Gas Reforming rig, this thesis includes a report that summarizes the analysis and solution of building a controls and data acquisition system for this setup. It describes the purpose of the sensors selected along with their placement throughout the system. Moreover, it includes an explanation of the planned data collection system, along with two models describing the reforming process useful for system control. For the Biodiesel Single Cylinder Test Stand, the responsibility was to implement the CDAQ system for data collection. This project comprised a variety of different sensors that are being used collect the combustion characteristics of different biodiesel formulations. This project is currently being used by other graduates in order to complete their projects for subsequent publication. For the Reformate Assisted Biodiesel Combustion architecture, the author developed a reformate injection system to test different hydrogen and carbon monoxide mixtures as combustion augmentation. Hydrogen combustion has certain limiting factors, such as pre-ignition in spark ignition engines and inability to work as a singular fuel in compression ignition engines. To offset these issues, a dual-fuel methodology is utilized by injecting a hydrogen/carbon monoxide mixture into the intake stream of a diesel engine operating on biodiesel. While carbon monoxide does degrade some of the

  10. Effect of porosity heterogeneity on the permeability and tortuosity of gas diffusion layers in polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Nabovati, Aydin; Hinebaugh, James; Bazylak, Aimy; Amon, Cristina H.

    2014-02-01

    In this paper, we study the effect of porosity heterogeneity on the bulk hydrodynamic properties (permeability and tortuosity) of simulated gas diffusion layers (GDLs). The porosity distributions of the heterogeneous reconstructed samples are similar to those previously reported in the literature for Toray TGP-H 120™ GDLs. We use the lattice Boltzmann method to perform pore-level flow simulations in the reconstructed GDL samples. Using the results of pore-level simulations, the effect of porosity distribution is characterized on the predicted in- and cross-plane permeability and tortuosity. It was found that porosity heterogeneity causes a higher in-plane permeability and lower in-plane tortuosity, while the effect is opposite in the cross-plane direction, that is a lower cross-plane permeability and a higher cross-plane tortuosity. We further investigate the effect of adding poly-tetra-fluoro-ethylene (PTFE) & binder material to the reconstructed GDL samples. Three fiber volume percentages of 50, 75, and 100% are considered. Overall, increasing the fiber volume percentage reduces the predicted in- and cross-plane permeability and tortuosity values. A previously reported relationship for permeability of fibrous materials is fitted to the predicted permeability values, and the magnitude of the fitting parameter is reported as a function of fiber volume percentage.

  11. X-ray Tomographic Analysis of Porosity Distributions in Gas Diffusion Layers of Proton Exchange Membrane Fuel Cells

    International Nuclear Information System (INIS)

    Odaya, S.; Phillips, R.K.; Sharma, Y.; Bellerive, J.; Phillion, A.B.; Hoorfar, M.

    2015-01-01

    This paper describes a method to characterize the structure of polytetrafluoroethylene (PTFE) treated gas diffusion layers (GDLs) with and without microporous layers (MPLs) using 3D X-ray micro computed tomographic (μCT) microscopy. In this work, the structure of single and dual layer GDLs is evaluated via μCT for various GDL samples (such as Toray TGP-H-060 and AvCarb EP40) loaded with different MPLs. A new method is presented for separating, or segmenting, the various phases of the GDL, i.e., void space, carbon fiber (including binder and PTFE), and MPL. Through analysis, it was found that the variation in bulk porosity and the average pore diameter of the GDLs depends highly on the GDL series manufacturing and treatment processes. Using advanced image analysis techniques, routines were developed to accurately segment the GDL fibers (including binder/PTFE) and the MPL. The percentage of the intruding MPL material into the carbon fiber paper as a function of the GDL thickness was successfully found for dual layer GDLs, with varying PTFE content and areal weight loading in the MPL. This analysis provides invaluable insight into the physical microstructure of paper-based GDLs, emphasizing the heterogeneous porosity distribution of single layer GDLs and the interaction of the MPL with the carbon fiber paper of dual layer GDLs

  12. Novel gas target for laser wakefield accelerators

    Science.gov (United States)

    Aniculaesei, C.; Kim, Hyung Taek; Yoo, Byung Ju; Oh, Kyung Hwan; Nam, Chang Hee

    2018-02-01

    A novel gas target for interactions between high power lasers and gaseous medium, especially for laser wakefield accelerators, has been designed, manufactured, and characterized. The gas target has been designed to provide a uniform density profile along the central gas cell axis by combining a gas cell and slit nozzle. The gas density has been tuned from ˜1017 atoms/cm3 to ˜1019 atoms/cm3 and the gas target length can be varied from 0 to 10 cm; both changes can be made simultaneously while keeping the uniform gas profile. The gas density profile inside the gas cell has been measured using interferometry and validated using computational fluid dynamics.

  13. 4E analysis and multi objective optimization of a micro gas turbine and solid oxide fuel cell hybrid combined heat and power system

    Science.gov (United States)

    Sanaye, Sepehr; Katebi, Arash

    2014-02-01

    Energy, exergy, economic and environmental (4E) analysis and optimization of a hybrid solid oxide fuel cell and micro gas turbine (SOFC-MGT) system for use as combined generation of heat and power (CHP) is investigated in this paper. The hybrid system is modeled and performance related results are validated using available data in literature. Then a multi-objective optimization approach based on genetic algorithm is incorporated. Eight system design parameters are selected for the optimization procedure. System exergy efficiency and total cost rate (including capital or investment cost, operational cost and penalty cost of environmental emissions) are the two objectives. The effects of fuel unit cost, capital investment and system power output on optimum design parameters are also investigated. It is observed that the most sensitive and important design parameter in the hybrid system is fuel cell current density which has a significant effect on the balance between system cost and efficiency. The selected design point from the Pareto distribution of optimization results indicates a total system exergy efficiency of 60.7%, with estimated electrical energy cost 0.057 kW-1 h-1, and payback period of about 6.3 years for the investment.

  14. Development of a 3D cell-centered Lagrangian scheme for the numerical modeling of the gas dynamics and hyper-elasticity systems

    International Nuclear Information System (INIS)

    Georges, Gabriel

    2016-01-01

    High Energy Density Physics (HEDP) flows are multi-material flows characterized by strong shock waves and large changes in the domain shape due to rare faction waves. Numerical schemes based on the Lagrangian formalism are good candidates to model this kind of flows since the computational grid follows the fluid motion. This provides accurate results around the shocks as well as a natural tracking of multi-material interfaces and free-surfaces. In particular, cell-centered Finite Volume Lagrangian schemes such as GLACE (Godunov-type Lagrangian scheme Conservative for total Energy) and EUCCLHYD (Explicit Unstructured Cell-Centered Lagrangian Hydrodynamics) provide good results on both the modeling of gas dynamics and elastic-plastic equations. The work produced during this PhD thesis is in continuity with the work of Maire and Nkonga [JCP, 2009] for the hydrodynamic part and the work of Kluth and Despres [JCP, 2010] for the hyper elasticity part. More precisely, the aim of this thesis is to develop robust and accurate methods for the 3D extension of the EUCCLHYD scheme with a second-order extension based on MUSCL (Monotonic Upstream-centered Scheme for Conservation Laws) and GRP (Generalized Riemann Problem) procedures. A particular care is taken on the preservation of symmetries and the monotonicity of the solutions. The scheme robustness and accuracy are assessed on numerous Lagrangian test cases for which the 3D extensions are very challenging. (author) [fr

  15. GAS BEARING

    Science.gov (United States)

    Skarstrom, C.W.

    1960-09-01

    A gas lubricated bearing for a rotating shaft is described. The assembly comprises a stationary collar having an annular member resiliently supported thereon. The collar and annular member are provided with cooperating gas passages arranged for admission of pressurized gas which supports and lubricates a bearing block fixed to the rotatable shaft. The resilient means for the annular member support the latter against movement away from the bearing block when the assembly is in operation.

  16. Requirements for gas quality and gas appliances

    NARCIS (Netherlands)

    Levinsky, Howard; Gersen, Sander; Kiewiet, Bert

    2015-01-01

    Introduction The gas transmission network in the Netherlands transports two different qualities of gas, low-calorific gas known as G-gas or L-gas and, high calorific gas (H-gas). These two gas qualities are transported in separate networks, and are connected by means of five blending and conversion

  17. Gas magnetometer

    Science.gov (United States)

    Walker, Thad Gilbert; Lancor, Brian Robert; Wyllie, Robert

    2016-05-03

    Measurement of a precessional rate of a gas, such as an alkali gas, in a magnetic field is made by promoting a non-uniform precession of the gas in which substantially no net magnetic field affects the gas during a majority of the precession cycle. This allows sensitive gases that would be subject to spin-exchange collision de-phasing to be effectively used for extremely sensitive measurements in the presence of an environmental magnetic field such as the Earth's magnetic field.

  18. Gas separating

    Science.gov (United States)

    Gollan, A.

    1988-03-29

    Feed gas is directed tangentially along the non-skin surface of gas separation membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing. 3 figs.

  19. Novel thin/tunable gas diffusion electrodes with ultra-low catalyst loading for hydrogen evolution reactions in proton exchange membrane electrolyzer cells

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Zhenye; Yang, Gaoqiang; Mo, Jingke; Li, Yifan; Yu, Shule; Cullen, David A.; Retterer, Scott T.; Toops, Todd J.; Bender, Guido; Pivovar, Bryan S.; Green, Johney B.; Zhang, Feng-Yuan

    2018-05-01

    Proton exchange membrane electrolyzer cells (PEMECs) have received great attention for hydrogen/oxygen production due to their high efficiencies even at low-temperature operation. Because of the high cost of noble platinum-group metal (PGM) catalysts (Ir, Ru, Pt, etc.) that are widely used in water splitting, a PEMEC with low catalyst loadings and high catalyst utilizations is strongly desired for its wide commercialization. In this study, the ultrafast and multiscale hydrogen evolution reaction (HER) phenomena in an operating PEMEC is in-situ observed for the first time. The visualization results reveal that the HER and hydrogen bubble nucleation mainly occur on catalyst layers at the rim of the pores of the thin/tunable liquid/gas diffusion layers (TT-LGDLs). This indicates that the catalyst material of the conventional catalyst-coated membrane (CCM) that is located in the middle area of the LGDL pore is underutilized/inactive. Based on this discovery, a novel thin and tunable gas diffusion electrode (GDE) with a Pt catalyst thickness of 15 nm and a total thickness of about 25 um has been proposed and developed by taking advantage of advanced micro/nano manufacturing. The novel thin GDEs are comprehensively characterized both ex-situ and in-situ, and exhibit excellent PEMEC performance. More importantly, they achieve catalyst mass activity of up to 58 times higher than conventional CCM at 1.6 V under the operating conditions of 80 degrees C and 1 atm. This study demonstrates a promising concept for PEMEC electrode development, and provides a direction of future catalyst designs and fabrications for electrochemical devices.

  20. Microstructure-property relationships in a gas diffusion layer (GDL) for Polymer Electrolyte Fuel Cells, Part I: effect of compression and anisotropy of dry GDL

    International Nuclear Information System (INIS)

    Holzer, L.; Pecho, O.; Schumacher, J.; Marmet, Ph.; Stenzel, O.; Büchi, F.N.; Lamibrac, A.; Münch, B.

    2017-01-01

    Highlights: • Methods are developed to predict transport properties of dry GDL in PE Fuel Cells. • Diffusivity and Permeability are reliably predicted based on 3D characteristics. • Predictions based on 3D microstructure match well with numerical simulations. • Anisotropy is due to in- and through-plane variation of tortuosity and hydraulic rad. • The methods can be used to predict relative permeability and diffusivity in wet GDL. - Abstract: New quantitative relationships are established between effective properties (gas diffusivity, permeability and electrical conductivity) for a dry GDL (25 BA) from SGL Carbon with the corresponding microstructure characteristics from 3D analysis. These microstructure characteristics include phase volume fractions, geodesic tortuosity, constrictivity and hydraulic radius. The latter two parameters include information from two different size distribution curves for bulges (continuous PSD) and for bottlenecks (MIP-PSD). X-ray tomographic microscopy is performed for GDL at different compression levels and the micro-macro-relationships are then established for the in-plane and through-plane directions. The predicted properties based on these relationships are compared with numerical transport simulations, which give very similar results and which can be summarized as follows: Gas diffusivity is higher in the in-plane than in the through-plane direction. Its variation with compression is mainly related to changes of porosity and geodesic tortuosity. Permeability is dominated by variations in hydraulic radius. Through-plane permeability is slightly higher than in-plane. Anisotropy of electrical conductivity is controlled by tortuosity, which is higher for the through-plane direction. A table with new quantitative relationships is provided, which are considered to be more accurate and precise than older descriptions (e.g. Carman-Kozeny, Bruggeman), because they are based on detailed topological information from 3D analysis

  1. Cell formation effects on the burning speeds and flame front area of synthetic gas at high pressures and temperatures

    International Nuclear Information System (INIS)

    Askari, Omid; Elia, Mimmo; Ferrari, Matthew; Metghalchi, Hameed

    2017-01-01

    Highlights: • Effect of cell formation on burning speed and flame surface area is investigated. • A new developed non-dimensional number called cellularity factor is introduced. • Cellular burning speed and mass burning rate are calculated using differential based multi-shell model. • Flame instability is studied using thermo-diffusive and hydrodynamics effects. • Power law correlations are developed for cellular burning speeds and mass burning rates. - Abstract: Cellular burning speeds and mass burning rates of premixed syngas/oxidizer/diluent (H_2/CO/O_2/He) have been determined at high pressures and temperatures over a wide range of equivalence ratios which are at engine-relevant conditions. Working on high pressure combustion helps to reduce the pollution and increase the energy efficiency in combustion devices. The experimental facilities consisted of two spherical and cylindrical chambers. The spherical chamber, which can withstand high pressures up to 400 atm, was used to collect pressure rise data due to combustion, to calculate cellular burning speed and mass burning rate. For flame structure and instability analysis the cylindrical chamber was used to take pictures of propagating flame using a high speed CMOS camera and a schlieren photography system. A new differential based multi-shell model based on pressure rise data was used to determine the cellular burning speed and mass burning rate. In this paper, cellular burning speed and mass burning rate of H_2/CO/O_2/He mixture have been measured for a wide range of equivalence ratios from 0.6 to 2, temperatures from 400 to 750 K and pressures from 2 to 50 atm for three hydrogen concentrations of 5, 10 and 25% in the syngas. The power law correlations for cellular burning speed and mass burning rate were developed as a function of equivalence ratio, temperature and pressure. In this study a new developed parameter, called cellularity factor, which indicates the cell formation effect on flame

  2. Manure gas

    Energy Technology Data Exchange (ETDEWEB)

    Carre, I

    1947-05-01

    A short description of the process is given, with gas yields from various feedstocks, and the composition of the gas. Short descriptions of several batch digester designs are given: Algerian, Salubra, Betur, Baudot-Hardoll and Ofta, and Somagaz. The utilization and the economics of the process are discussed. Two diagrams of Ducellier and Isman designs are included.

  3. Landfill gas

    International Nuclear Information System (INIS)

    Hartnell, Gaynor

    2000-01-01

    Following the UK Government's initiative for stimulating renewable energy through the Non-Fossil Fuel Obligation (NFFO), the UK landfill gas industry has more than trebled in size in just 4 years. As a result, UK companies are now in a strong position to offer their skills and services overseas. Ireland, Greece and Spain also resort heavily to disposal to landfill. Particularly rapid growth of the landfill gas market is expected in the OECD-Pacific and NAFTA areas. The article explains that landfill gas is a methane-rich mixture produced by anaerobic decomposition of organic wastes in landfills: under optimum conditions, up to 500 cubic meters of gas can be obtained from 1 tonne of biodegradable waste. Data on the number and capacity of sites in the UK are given. The Landfill Gas Association runs courses to counteract the skills shortage in the UK, and tailored courses for overseas visitors are planned

  4. Design and exergetic analysis of a novel carbon free tri-generation system for hydrogen, power and heat production from natural gas, based on combined solid oxide fuel and electrolyser cells

    Energy Technology Data Exchange (ETDEWEB)

    Perdikaris, N.; Hofmann, Ph.; Spyrakis, S. [Laboratory of Steam Boilers and Thermal Plants, School of Mechanical Engineering, Thermal Engineering Section, National Technical University of Athens, 9 Heroon Polytechniou Ave., Zografou, 15780 Athens (Greece); Panopoulos, K.D. [Institute for Solid Fuels Technology and Applications, Centre for Research and Technology Hellas, 4th km N.R. Ptolemais-Kozani, P.O. Box 95, 50200 Ptolemais (Greece); Kakaras, E. [Laboratory of Steam Boilers and Thermal Plants, School of Mechanical Engineering, Thermal Engineering Section, National Technical University of Athens, 9 Heroon Polytechniou Ave., Zografou, 15780 Athens (Greece); Institute for Solid Fuels Technology and Applications, Centre for Research and Technology Hellas, 4th km N.R. Ptolemais-Kozani, P.O. Box 95, 50200 Ptolemais (Greece)

    2010-03-15

    The Solid Oxide Cells (SOCs) are able to operate in two modes: (a) the Solid Oxide Fuel Cells (SOFCs) that produce electricity and heat and (b) the Solid Oxide Electrolyser Cells (SOEC) that consume electricity and heat to electrolyse water and produce hydrogen and oxygen. The present paper presents a carbon free SOEC/SOFC combined system for the production of hydrogen, electricity and heat (tri-generation) from natural gas fuel. Hydrogen can be locally used as automobile fuel whereas the oxygen produced in the SOEC is used to combust the depleted fuel from the SOFC, which is producing electricity and heat from natural gas. In order to achieve efficient carbon capture in such a system, water steam should be used as the SOEC anode sweep gas, to allow the production of nitrogen free flue gases. The SOEC and SOFC operations were matched through modeling of all components in Aspenplus trademark. The exergetic efficiency of the proposed decentralised system is 28.25% for power generation and 18.55% for production of hydrogen. The system is (a) carbon free because it offers an almost pure pressurised CO{sub 2} stream to be driven for fixation via parallel pipelines to the natural gas feed, (b) does not require any additional water for its operation and (c) offers 26.53% of its energetic input as hot water for applications. (author)

  5. The golden age of natural gas

    International Nuclear Information System (INIS)

    Anon.

    1999-01-01

    The experts of energy policy agree to predict a brilliant future for natural gas. Among fossil energies, natural gas produces the least quantity of CO 2 . Geological reserves are estimated to 65 years for gas and 43 years for petroleum. Throughout the world, industrial infrastructures of gas production, transport and distribution are being developed, for instance 430000 km of gas pipeline are planned. In western Europe half the increase of gas demand by 2010 will be due to electricity production. Innovative techniques using natural gas are studied in various fields: cogeneration, transport, urban heating and fuel cells. The gas-fed fuel cell is based on a reversed electrolysis: hydrogen produced by the decomposition of natural gas interacts with oxygen and yields electricity. (A.C.)

  6. Data Pre-Processing Method to Remove Interference of Gas Bubbles and Cell Clusters During Anaerobic and Aerobic Yeast Fermentations in a Stirred Tank Bioreactor

    Science.gov (United States)

    Princz, S.; Wenzel, U.; Miller, R.; Hessling, M.

    2014-11-01

    One aerobic and four anaerobic batch fermentations of the yeast Saccharomyces cerevisiae were conducted in a stirred bioreactor and monitored inline by NIR spectroscopy and a transflectance dip probe. From the acquired NIR spectra, chemometric partial least squares regression (PLSR) models for predicting biomass, glucose and ethanol were constructed. The spectra were directly measured in the fermentation broth and successfully inspected for adulteration using our novel data pre-processing method. These adulterations manifested as strong fluctuations in the shape and offset of the absorption spectra. They resulted from cells, cell clusters, or gas bubbles intercepting the optical path of the dip probe. In the proposed data pre-processing method, adulterated signals are removed by passing the time-scanned non-averaged spectra through two filter algorithms with a 5% quantile cutoff. The filtered spectra containing meaningful data are then averaged. A second step checks whether the whole time scan is analyzable. If true, the average is calculated and used to prepare the PLSR models. This new method distinctly improved the prediction results. To dissociate possible correlations between analyte concentrations, such as glucose and ethanol, the feeding analytes were alternately supplied at different concentrations (spiking) at the end of the four anaerobic fermentations. This procedure yielded low-error (anaerobic) PLSR models for predicting analyte concentrations of 0.31 g/l for biomass, 3.41 g/l for glucose, and 2.17 g/l for ethanol. The maximum concentrations were 14 g/l biomass, 167 g/l glucose, and 80 g/l ethanol. Data from the aerobic fermentation, carried out under high agitation and high aeration, were incorporated to realize combined PLSR models, which have not been previously reported to our knowledge.

  7. Treatment of Gas

    Science.gov (United States)

    ... Funding IFFGD Symposium reports Industry Council Contact Us Treatment of Gas You are here: Home Symptoms & Causes Intestinal Gas ... Controlling Intestinal Gas Foods That May Cause Gas Treatment of Gas Tips on Controlling Gas Adapted from IFFGD Publication # ...

  8. Asian gas

    International Nuclear Information System (INIS)

    Masuda, T.

    1990-01-01

    This paper reports on natural gas which now appears ready to take a leading role on the world energy stage. Demand for natural gas, and specifically LNG, will be strong throughout the world, particularly in Asia. Indonesia and Malaysia will become much more dependent on natural gas in the Asian market. In Thailand, where remarkable economic growth has been fueled by imported oil and domestically produced natural gas, LNG may soon have to be imported from neighboring countries. The author sees Thailand's imports of natural gas increasing from 1.5 to 4.5 million tons annually. Similarly, Korea's imports of LNG will rise from 2 to 8 million tons between 1987 and 2000. In Japan, energy demand is expected to increase at an even faster rate in the 1990s. Given the opposition to nuclear power generation and growing concern about the greenhouse effect, it is likely that LNG will satisfy a major portion of Japan's increasing demand for energy. Japanese gas companies are studying the possibility of establishing a national pipeline network to move gas beyond metropolitan areas

  9. Large scale simulation of liquid water transport in a gas diffusion layer of polymer electrolyte membrane fuel cells using the lattice Boltzmann method

    Science.gov (United States)

    Sakaida, Satoshi; Tabe, Yutaka; Chikahisa, Takemi

    2017-09-01

    A method for the large-scale simulation with the lattice Boltzmann method (LBM) is proposed for liquid water movement in a gas diffusion layer (GDL) of polymer electrolyte membrane fuel cells. The LBM is able to analyze two-phase flows in complex structures, however the simulation domain is limited due to heavy computational loads. This study investigates a variety means to reduce computational loads and increase the simulation areas. One is applying an LBM treating two-phases as having the same density, together with keeping numerical stability with large time steps. The applicability of this approach is confirmed by comparing the results with rigorous simulations using actual density. The second is establishing the maximum limit of the Capillary number that maintains flow patterns similar to the precise simulation; this is attempted as the computational load is inversely proportional to the Capillary number. The results show that the Capillary number can be increased to 3.0 × 10-3, where the actual operation corresponds to Ca = 10-5∼10-8. The limit is also investigated experimentally using an enlarged scale model satisfying similarity conditions for the flow. Finally, a demonstration is made of the effects of pore uniformity in GDL as an example of a large-scale simulation covering a channel.

  10. A novel approach to determine the in-plane thermal conductivity of gas diffusion layers in proton exchange membrane fuel cells

    Science.gov (United States)

    Sadeghi, E.; Djilali, N.; Bahrami, M.

    Heat transfer through the gas diffusion layer (GDL) is a key process in the design and operation of a proton exchange membrane (PEM) fuel cell. The analysis of this process requires determination of the effective thermal conductivity. This transport property differs significantly in the through-plane and in-plane directions due to the anisotropic micro-structure of the GDL. A novel test bed that allows separation of in-plane effective thermal conductivity and thermal contact resistance in GDLs is described in this paper. Measurements are performed using Toray carbon paper TGP-H-120 samples with varying polytetrafluoroethylene (PTFE) content at a mean temperature of 65-70 °C. The measurements are complemented by a compact analytical model that achieves good agreement with experimental data. The in-plane effective thermal conductivity is found to remain approximately constant, k ≈ 17.5 W m -1 K -1, over a wide range of PTFE content, and its value is about 12 times higher than that for through-plane conductivity.

  11. Improvement of activated carbons as oxygen reduction catalysts in neutral solutions by ammonia gas treatment and their performance in microbial fuel cells

    KAUST Repository

    Watson, Valerie J.

    2013-11-01

    Commercially available activated carbon (AC) powders from different precursor materials (peat, coconut shell, coal, and hardwood) were treated with ammonia gas at 700 C to improve their performance as oxygen reduction catalysts in neutral pH solutions used in microbial fuel cells (MFCs). The ammonia treated ACs exhibited better catalytic performance in rotating ring-disk electrode tests than their untreated precursors, with the bituminous based AC most improved, with an onset potential of Eonset = 0.12 V (untreated, Eonset = 0.08 V) and n = 3.9 electrons transferred in oxygen reduction (untreated, n = 3.6), and the hardwood based AC (treated, E onset = 0.03 V, n = 3.3; untreated, Eonset = -0.04 V, n = 3.0). Ammonia treatment decreased oxygen content by 29-58%, increased nitrogen content to 1.8 atomic %, and increased the basicity of the bituminous, peat, and hardwood ACs. The treated coal based AC cathodes had higher maximum power densities in MFCs (2450 ± 40 mW m-2) than the other AC cathodes or a Pt/C cathode (2100 ± 1 mW m-2). These results show that reduced oxygen abundance and increased nitrogen functionalities on the AC surface can increase catalytic performance for oxygen reduction in neutral media. © 2013 Elsevier B.V. All rights reserved.

  12. Modeling the Liquid Water Transport in the Gas Diffusion Layer for Polymer Electrolyte Membrane Fuel Cells Using a Water Path Network

    Directory of Open Access Journals (Sweden)

    Dietmar Gerteisen

    2013-09-01

    Full Text Available In order to model the liquid water transport in the porous materials used in polymer electrolyte membrane (PEM fuel cells, the pore network models are often applied. The presented model is a novel approach to further develop these models towards a percolation model that is based on the fiber structure rather than the pore structure. The developed algorithm determines the stable liquid water paths in the gas diffusion layer (GDL structure and the transitions from the paths to the subsequent paths. The obtained water path network represents the basis for the calculation of the percolation process with low calculation efforts. A good agreement with experimental capillary pressure-saturation curves and synchrotron liquid water visualization data from other literature sources is found. The oxygen diffusivity for the GDL with liquid water saturation at breakthrough reveals that the porosity is not a crucial factor for the limiting current density. An algorithm for condensation is included into the model, which shows that condensing water is redirecting the water path in the GDL, leading to an improved oxygen diffusion by a decreased breakthrough pressure and changed saturation distribution at breakthrough.

  13. Accurate Determination of Platinum, Palladium, and Rhodium in Ryegrass using Collision Cell Inductively Coupled Plasma Mass Spectrometry with Xenon as Collision Gas

    International Nuclear Information System (INIS)

    Amr, M.A.

    2011-01-01

    Inductively coupled plasma mass spectrometry with an octupole collision cell was used for determination of Pt, Pd and Rh in ryegrass (Lolium multiflorum) which was grown hydroponically. Xenon was used as a collision gas to reduce serious polyatomic interferences formed by combination of matrix elements such as CI, Cu, Hf, Sr, Zn, Zr, Y and REE with O, N, C, and Ar. The detection limits for Pt, Pd and Rh in spiked ryegrass are 1.8, 4.2, and 0.8 ppt, respectively. The results for Pt, Pd and Rh in reference materials (NIST SRM 2557, recycled monolith auto catalyst) are in agreement with the certified values. The bioaccumulation of Pt, Pd and Rh by ryegrass grown hydroponically with nutrient solutions containing Pt, Pd and Rh was studied. The obtained results showed that most of the studied metals were accumulated in roots, and only a small fraction was metabolized and transported to leaves. The highest bioaccumulation factors were obtained for Pd and Rh in roots and for Pt in leaves

  14. Gas dusulfurization

    International Nuclear Information System (INIS)

    Powell, B.E.; Bakhshi, V.S.; Randolph, D.A.

    1984-01-01

    A process for adsorbing sulfur dioxide from a gas comprising contacting a gas containing SO 2 , such as a flue gas, with about stoichiometric amounts of a specially prepared calcium oxide so that substantially all of the sulfur dioxide content is reacted throughout the calcium oxide particle to form a calcium sulfate reaction product. The useful calcium oxide particles comprise a highly voided skeletal structure of very large surface area and large pore volume with numerous macro pores. Such particles are obtained by flash calcining sand-size grains of calcium carbonate, such as aragonite, calcite or dolomite

  15. Gas turbines

    Energy Technology Data Exchange (ETDEWEB)

    Farahan, E.; Eudaly, J.P.

    1978-10-01

    This evaluation provides performance and cost data for commercially available simple- and regenerative-cycle gas turbines. Intercooled, reheat, and compound cycles are discussed from theoretical basis only, because actual units are not currently available, except on a special-order basis. Performance characteristics investigated include unit efficiency at full-load and off-design conditions, and at rated capacity. Costs are tabulated for both simple- and regenerative-cycle gas turbines. The output capacity of the gas turbines investigated ranges from 80 to 134,000 hp for simple units and from 12,000 to 50,000 hp for regenerative units.

  16. Volcanic Gas

    Science.gov (United States)

    ... offensive odor. It is sometimes referred to as sewer gas. Interestingly, the human nose is more sensitive ... the atmosphere where they can potentially cause acid rain. In an ash -producing eruption, ash particles are ...

  17. Gas - flatulence

    Science.gov (United States)

    ... Gas and other symptoms such as stomach pain, rectal pain, heartburn, nausea, vomiting, diarrhea, constipation, fever, or ... Copyright 1997-2018, A.D.A.M., Inc. Duplication for commercial use must be authorized in writing ...

  18. Gas sensor

    International Nuclear Information System (INIS)

    Dorogan, V.; Korotchenkov, Gh.; Vieru, T.; Prodan, I.

    2003-01-01

    The invention relates to the gas sensors on base of metal-oxide films (SnO, InO), which may be used for enviromental control, in the fireextinguishing systema etc. The gas includes an insulating substrate, an active layer, a resistive layer with ohmic contacts. The resistive layer has two or more regions with dofferent resistances , and on the active layer are two or more pairs of ohmic contacts

  19. Tomorrow, gas

    International Nuclear Information System (INIS)

    Icart, Laura; Jean, Pascale; Georget, Cyrille; Schmill, Rafael

    2017-01-01

    This document contains 12 articles notably addressing the importance of natural gas production and supplies in Europe. The themes of the articles are: the advantages of natural gas in the context of energy and environmental policies, energy diversification, energy supply in the local territories, etc.; the position of GrDF, one of the main French natural gas supplier; LPG (butane, propane), a solution which popularity grows in remote areas; the Gaya project (production of renewable gas from dry biomass); a panorama of gas supply routes in Europe; the situation of gas in Europe's energy supply and consumption; the promotion of LNG fuel for maritime and fluvial ships; why the small scale LNG could be the next revolution; presentation of the new 'Honfleur' ferry (using LNG fuel) that will cross the English Channel by 2019; carbon market and the role of ETS for the energy policy in Europe facing the climatic change challenge; presentation of the French 'Climate Plan' that aims to engage France into a carbon neutrality by 2050; presentation of the French policy against air pollution; economic growth, energy, climate: how to square this circle?

  20. Hydrodynamic performance of a single-use aerated stirred bioreactor in animal cell culture: applications of tomography, dynamic gas disengagement (DGD), and CFD.

    Science.gov (United States)

    Kazemzadeh, Argang; Elias, Cynthia; Tamer, Melih; Ein-Mozaffari, Farhad

    2018-05-01

    The hydrodynamics of gas-liquid two-phase flow in a single-use bioreactor were investigated in detail both experimentally and numerically. Electrical resistance tomography (ERT) and dynamic gas disengagement (DGD) combined with computational fluid dynamics (CFD) were employed to assess the effect of the volumetric gas flow rate and impeller speed on the gas-liquid flow field, local and global gas holdup values, and Sauter mean bubble diameter. From the results obtained from DGD coupled with ERT, the bubble sizes were determined. The experimental data indicated that the total gas holdup values increased with increasing both the rotational speed of impeller and volumetric gas flow rate. Moreover, the analysis of the flow field generated inside the aerated stirred bioreactor was conducted using CFD results. Overall, a more uniform distribution of the gas holdup was obtained at impeller speeds ≥ 100 rpm for volumetric gas flow rates ≥ 1.6 × 10 -5  m 3 /s.

  1. Achievement report (edition B) for fiscal 1999 on development of technology to manufacture coal gas for fuel cells. Studies by using pilot test facilities (Volumes for equipment fabrication and constructions, and trial run design); 1999 nendo seika hokokusho (B ban). Nenryo denchi you sekitan gas seizo gijutsu kaihatsu - Pilot setsubi ni yoru kenkyu (kisokoji kiki seisaku hen shiunten sekkei hen)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    With an objective to develop a coal gas manufacturing system for fuel cells, research and development has been performed on a oxygen-blown coal gasifier and researches on a technology to purify gases for fuel cells. This paper summarizes the achievements in fiscal 1999. The current fiscal year has performed, among other the pilot plant construction works, execution of the above-the-ground constructions for the operation center and compressor room building, construction of the cooling water tanks, and partial improvement of roads in the plant site. In the gasifier facilities, items of equipment were fabricated, some of the outsourced articles were procured, and the installations thereof were carried out. For the gas purifying equipment, installation of the gas analyzer room was executed. In the trial run design, discussions were given on the systematic improvements in the test items, the gas sampling procedures, the unit protecting interlock, and the facility protecting logic. For the trial run design, establishment has been implemented on the efficient and functional test plans by establishing priority on the tests to be executed, so that the development items demanded in the pilot test and research can be achieved within the limited test processes. (NEDO)

  2. Gas war

    International Nuclear Information System (INIS)

    Shiry, J.

    1992-01-01

    The sale of natural gas to California is one of the most complex and contested trade disputes between the USA and Canada. The background and the issues involved are discussed. An oversupply of Canadian gas, combined with USA subsidies for producing coalbed methane and a general oversupply of gas in the USA, have made spot gas prices decline to unexpectedly low levels. California regulators have responded to this situation by trying to secure the lowest possible prices for consumers, thereby causing them to abandon long-standing trade policies with Canada. The main agent of this change is the California Public Utilities Commission (CPUC), whose actions have reduced the value of Canadian exports and Alberta government revenues by at least $250 million annually. CPUC supported buying from a supply pool (Alberta ampersand Southern Gas) since it provided monopoly purchasing power, and CPUC's policy against pipeline expansion produced the limited access to California that the CPUC now cites as evidence of a producer cartel. CPUC has interfered in contracts with Canadian producers in its pipeline access policies, its capacity brokering decision of 1991, and its reasonableness test for past sales. In its haste to force its own view of market results onto existing contractual relationships, the CPUC is not allowing open negotiations to reshape the relationship, and CPUC actions may be generating countermeasures by Alberta that are inappropriate under deregulation. 3 figs

  3. Gas attack

    Energy Technology Data Exchange (ETDEWEB)

    North, D.

    1977-08-01

    Consumersfirst Ltd. is reacting to deregulation with a massive advertising campaign. The gas utility is owned by Consumers Gas Energy Inc., and is struggling to hold onto its 35 per cent share of Ontario`s two million residential natural gas buyers. An industry analyst pointed out that deregulation could mean that Consumers` Gas has much to lose: customers, market share, control of the assets and control of the process. The Ontario Energy Board (OEB) however, had specified that Consumersfirst is not to proceed with paperwork to sign up new customers until the OEB issues a draft code-of-conduct that would prevent cross-subsidizing between regulated franchise holders. This has now been done, and several heavyweights such as Calgary-based Suncor Energy Inc., Union Gas of Chatham, Ontario, and the US-based Enron Corp. of Houston, have started campaigns to sign up potential consumers. It is predicted that brand loyalty will be a factor, but in the end, like long distance telephone rates, it will all come down to pricing, and a winning formula is not easy to find.

  4. Studies on the efficiency during reactivation of a generation system based on natural gas reformer and a 5 k W fuel cell; Estudos de eficiencia durante reativacao de um sistema de geracao baseado em reformador de gas natural e celula a combustivel de 5 kW

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Francisco da Costa; Furtado, Jose Geraldo de Melo; Silva Junior, Fernando Rodrigues da; Serra, Eduardo Torres [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil)]. E-mail: fcl@cepel.br

    2008-07-01

    Fuel cell based power generation systems have been pointing as promising technology for stationary applications mainly to supply power to critical loads. Among several types of fuel cells the Polymer Electrolyte Membrane Fuel Cells (PEMFC) are the main type used around the world. Nowadays reformers are widely employed to produce hydrogen for fuel cells. The Fuel Cell Laboratory of CEPEL has a power plant based on a 5 kW PEMFC and a natural gas reformer. For a long time the PEMFC was inoperable due to reformer malfunctioning and during this time the full power availability of PEMFC was lost due to deactivation of its catalytic sites. In most cases this deactivation is reversible. So it was started a reactivation process aiming to recover the full operational condition of the PEMFC unit. During this process the gas flow relationship and efficiency of the reformer were studied. An analysis of the PEMFC reactivation was conducted where it was noted that the reactivation took place as expected. During the reactivation process the PEMFC and the whole system efficiency were analyzed. The results suggest that the PEMFC can reach efficiency compatible with conventional power generation systems thus allowing PEMFC technology to compete with these energy sources in point of efficiency. (author)

  5. A HIGH-PRECISION NEAR-INFRARED SURVEY FOR RADIAL VELOCITY VARIABLE LOW-MASS STARS USING CSHELL AND A METHANE GAS CELL

    Energy Technology Data Exchange (ETDEWEB)

    Gagné, Jonathan [Carnegie Institution of Washington DTM, 5241 Broad Branch Road NW, Washington, DC 20015 (United States); Plavchan, Peter [Department of Physics, Missouri State University, 901 S National Ave, Springfield, MO 65897 (United States); Gao, Peter [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Anglada-Escude, Guillem [School of Physics and Astronomy, Queen Mary University of London, 327 Mile End Rd, E1 4NS, London (United Kingdom); Furlan, Elise; Brinkworth, Carolyn; Ciardi, David R. [NASA Exoplanet Science Institute, California Institute of Technology, 770 S. Wilson Ave., Pasadena, CA 91125 (United States); Davison, Cassy; Henry, Todd J.; White, Russel [Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303 (United States); Tanner, Angelle [Mississippi State University, Department of Physics and Astronomy, Hilbun Hall, Starkville, MS 39762 (United States); Riedel, Adric R. [Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Latham, David; Johnson, John A. [Institute for Theory and Computation, Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Bottom, Michael [Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Mills, Sean [Department of Astronomy and Astrophysics, University of Chicago, 5640 S. Ellis Ave, Chicago, IL 60637 (United States); Beichman, Chas [NASA Exoplanet Science Institute, California Institute of Technology, Pasadena, CA 91125 (United States); Wallace, Kent; Mennesson, Bertrand [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr, Pasadena, CA 91125 (United States); Von Braun, Kaspar, E-mail: jgagne@carnegiescience.edu [Lowell Observatory, West Mars Hill Road, Flagstaff, AZ 86001 (United States); and others

    2016-05-01

    We present the results of a precise near-infrared (NIR) radial velocity (RV) survey of 32 low-mass stars with spectral types K2–M4 using CSHELL at the NASA InfraRed Telescope Facility in the K band with an isotopologue methane gas cell to achieve wavelength calibration and a novel, iterative RV extraction method. We surveyed 14 members of young (≈25–150 Myr) moving groups, the young field star ε Eridani, and 18 nearby (<25 pc) low-mass stars and achieved typical single-measurement precisions of 8–15 m s{sup −1}with a long-term stability of 15–50 m s{sup −1} over longer baselines. We obtain the best NIR RV constraints to date on 27 targets in our sample, 19 of which were never followed by high-precision RV surveys. Our results indicate that very active stars can display long-term RV variations as low as ∼25–50 m s{sup −1} at ≈2.3125 μ m, thus constraining the effect of jitter at these wavelengths. We provide the first multiwavelength confirmation of GJ 876 bc and independently retrieve orbital parameters consistent with previous studies. We recovered RV variabilities for HD 160934 AB and GJ 725 AB that are consistent with their known binary orbits, and nine other targets are candidate RV variables with a statistical significance of 3 σ –5 σ . Our method, combined with the new iSHELL spectrograph, will yield long-term RV precisions of ≲5 m s{sup −1} in the NIR, which will allow the detection of super-Earths near the habitable zone of mid-M dwarfs.

  6. Incorporating Embedded Microporous Layers into Topologically Equivalent Pore Network Models for Oxygen Diffusivity Calculations in Polymer Electrolyte Membrane Fuel Cell Gas Diffusion Layers

    International Nuclear Information System (INIS)

    Fazeli, Mohammadreza; Hinebaugh, James; Bazylak, Aimy

    2016-01-01

    Highlights: • Pore network model for modeling PEMFC MPL-coated GDL effective diffusivity. • Bilayered GDL (substrate and MPL) is modeled with a hybrid network of block MPL elements combined with discrete substrate pores. • Diffusivities of MPL-coated GDLs agree with analytical solutions. - Abstract: In this work, a voxel-based methodology is introduced for the hybridization of a pore network with interspersed nano-porous material elements allowing pore network based oxygen diffusivity calculations in a 3D image of a polymer electrolyte membrane (PEM) fuel cell gas diffusion layer (GDL) with an embedded microporous layer (MPL). The composite GDL is modeled by combining a hybrid network of block MPL elements with prescribed bulk material properties and a topologically equivalent network of larger discrete pores and throats that are directly derived from the 3D image of the GDL substrate. This hybrid network was incorporated into a pore network model, and effective diffusivity predictions of GDL materials with MPL coatings were obtained. Stochastically generated numerical models of carbon paper substrates with and without MPLs were used, and the pore space was directly extracted from this realistic geometry as the input for the pore network model. The effective diffusion coefficient of MPL-coated GDL materials was predicted from 3D images in a pore network modeling environment without resolving the nano-scale structure of the MPL. This method is particularly useful due to the disparate length scales that are involved when attempting to capture pore-scale transport in the GDL. Validation was performed by comparing our predicted diffusivity values to analytical predictions, and excellent agreement was observed. Upon conducting a mesh sensitivity study, it was determined that an MPL element size of 7 μm provided sufficiently high resolution for accurately describing the MPL nano-structure.

  7. A HIGH-PRECISION NEAR-INFRARED SURVEY FOR RADIAL VELOCITY VARIABLE LOW-MASS STARS USING CSHELL AND A METHANE GAS CELL

    International Nuclear Information System (INIS)

    Gagné, Jonathan; Plavchan, Peter; Gao, Peter; Anglada-Escude, Guillem; Furlan, Elise; Brinkworth, Carolyn; Ciardi, David R.; Davison, Cassy; Henry, Todd J.; White, Russel; Tanner, Angelle; Riedel, Adric R.; Latham, David; Johnson, John A.; Bottom, Michael; Mills, Sean; Beichman, Chas; Wallace, Kent; Mennesson, Bertrand; Von Braun, Kaspar

    2016-01-01

    We present the results of a precise near-infrared (NIR) radial velocity (RV) survey of 32 low-mass stars with spectral types K2–M4 using CSHELL at the NASA InfraRed Telescope Facility in the K band with an isotopologue methane gas cell to achieve wavelength calibration and a novel, iterative RV extraction method. We surveyed 14 members of young (≈25–150 Myr) moving groups, the young field star ε Eridani, and 18 nearby (<25 pc) low-mass stars and achieved typical single-measurement precisions of 8–15 m s −1 with a long-term stability of 15–50 m s −1 over longer baselines. We obtain the best NIR RV constraints to date on 27 targets in our sample, 19 of which were never followed by high-precision RV surveys. Our results indicate that very active stars can display long-term RV variations as low as ∼25–50 m s −1 at ≈2.3125 μ m, thus constraining the effect of jitter at these wavelengths. We provide the first multiwavelength confirmation of GJ 876 bc and independently retrieve orbital parameters consistent with previous studies. We recovered RV variabilities for HD 160934 AB and GJ 725 AB that are consistent with their known binary orbits, and nine other targets are candidate RV variables with a statistical significance of 3 σ –5 σ . Our method, combined with the new iSHELL spectrograph, will yield long-term RV precisions of ≲5 m s −1 in the NIR, which will allow the detection of super-Earths near the habitable zone of mid-M dwarfs.

  8. A mechanical-electrical finite element method model for predicting contact resistance between bipolar plate and gas diffusion layer in PEM fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Xinmin; Liu, Dong' an; Peng, Linfa [State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China); Ni, Jun [Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109-2125 (United States)

    2008-07-15

    Contact resistance between the bipolar plate (BPP) and the gas diffusion layer (GDL) plays a significant role on the power loss in a proton exchange membrane (PEM) fuel cell. There are two types of contact behavior at the interface of the BPP and GDL, which are the mechanical one and the electrical one. Furthermore, the electrical contact behavior is dependent on the mechanical one. Thus, prediction of the contact resistance is a coupled mechanical-electrical problem. The current FEM models for contact resistance estimation can only simulate the mechanical contact behavior and moreover they are based on the assumption that the contact surface is equipotential, which is not the case in a real BPP/GDL assembly due to the round corner and margin of the BPP. In this study, a mechanical-electrical FEM model was developed to predict the contact resistance between the BPP and GDL based on the experimental interfacial contact resistivity. At first, the interfacial contact resistivity was obtained by experimentally measuring the contact resistance between the GDL and a flat graphite plate of the same material and processing conditions as the BPP. Then, with the interfacial contact resistivity, the mechanical and electrical contact behaviors were defined and the potential distribution of the BPP/GDL assembly was analyzed using the mechanical-electrical FEM model. At last, the contact resistance was calculated according to the potential drop and the current of the contact surface. The numerical results were validated by comparing with those of the model reported previously. The influence of the round corner of the BPP on the contact resistance was also studied and it is found that there exists an optimal round corner that can minimize the contact resistance. This model is beneficial in understanding the mechanical and electrical contact behaviors between the BPP and GDL, and can be used to predict the contact resistance in a new BPP/GDL assembly. (author)

  9. Natural gas industry R and D

    International Nuclear Information System (INIS)

    Pavan, S.

    1992-01-01

    The last three decades have witnessed significant developments in engineering relative to the distribution and use of natural gas. This paper reviews these developments which, in natural gas distribution, include - polyethylene conduits, the use of radar to trace buried conduits, telemetering, innovative pressure reducing techniques and equipment, optimized retrofitting of buried pipelines, leak detection techniques, and energy recovery systems applied to pressure reducing operations. Relative to the efficient combustion and new uses of natural gas, the paper reviews the state-of-the-art in the design of compact wall mounted gas fired boilers for building space heating, gas fuelled space heating ventilation and air conditioning systems, and natural gas fed fuel cells

  10. Gas hydrates

    Digital Repository Service at National Institute of Oceanography (India)

    Ramprasad, T.

    , not all of them are white like snow. Some hydrates from the deep Gulf of Mexico are richly colored in shades of yellow, orange, or even red. The ice-like masses are beautiful, and contrast with the dull gray of deep sea muds. Hydrates from the Blake... volcanoes and associated gas hydrates: Marine Geology, v. 167, p. 29-42. Milkov, A.V. and R. Sassen, 2001a, Estimate of gas hydrate resource, northwestern Gulf of Mexico continental slope: Marine Geology, v. 179, pp. 71-83. Milkov, A.V., Sassen, R...

  11. Cowdung gas

    Energy Technology Data Exchange (ETDEWEB)

    A basic guide for the design and construction of a small biogas plant is presented. The gas holder consists of a battery of seven used oil drums bound together with interconnected via plastic piping. Most other components, with the exception of metal valves and joints, are made of wood, stone or cement.

  12. Gas sensor

    Science.gov (United States)

    Schmid, Andreas K.; Mascaraque, Arantzazu; Santos, Benito; de la Figuera, Juan

    2014-09-09

    A gas sensor is described which incorporates a sensor stack comprising a first film layer of a ferromagnetic material, a spacer layer, and a second film layer of the ferromagnetic material. The first film layer is fabricated so that it exhibits a dependence of its magnetic anisotropy direction on the presence of a gas, That is, the orientation of the easy axis of magnetization will flip from out-of-plane to in-plane when the gas to be detected is present in sufficient concentration. By monitoring the change in resistance of the sensor stack when the orientation of the first layer's magnetization changes, and correlating that change with temperature one can determine both the identity and relative concentration of the detected gas. In one embodiment the stack sensor comprises a top ferromagnetic layer two mono layers thick of cobalt deposited upon a spacer layer of ruthenium, which in turn has a second layer of cobalt disposed on its other side, this second cobalt layer in contact with a programmable heater chip.

  13. Manure gas

    Energy Technology Data Exchange (ETDEWEB)

    Carre, I

    1948-11-01

    Descriptions are given of several batch digesters: the Algerian, Salubra, Betur, Baudot-Hardoll and Ofla, and Somagaz designs. Sketches of two Ducellier and Isman designs are given with a photograph of an installation consisting of four contiguous, rectangular concrete tanks. There are short explanations of the fundamentals and economics of the process, and of the use of the gas.

  14. Improvement of activated carbons as oxygen reduction catalysts in neutral solutions by ammonia gas treatment and their performance in microbial fuel cells

    KAUST Repository

    Watson, Valerie J.; Nieto Delgado, Cesar; Logan, Bruce E.

    2013-01-01

    Commercially available activated carbon (AC) powders from different precursor materials (peat, coconut shell, coal, and hardwood) were treated with ammonia gas at 700 C to improve their performance as oxygen reduction catalysts in neutral p

  15. On-line gas chromatographic analysis of airborne particles

    Science.gov (United States)

    Hering, Susanne V [Berkeley, CA; Goldstein, Allen H [Orinda, CA

    2012-01-03

    A method and apparatus for the in-situ, chemical analysis of an aerosol. The method may include the steps of: collecting an aerosol; thermally desorbing the aerosol into a carrier gas to provide desorbed aerosol material; transporting the desorbed aerosol material onto the head of a gas chromatography column; analyzing the aerosol material using a gas chromatograph, and quantizing the aerosol material as it evolves from the gas chromatography column. The apparatus includes a collection and thermal desorption cell, a gas chromatograph including a gas chromatography column, heated transport lines coupling the cell and the column; and a quantization detector for aerosol material evolving from the gas chromatography column.

  16. Natural gas hydrate formation and inhibition in gas/crude oil/aqueous systems

    DEFF Research Database (Denmark)

    Daraboina, Nagu; Pachitsas, Stylianos; von Solms, Nicolas

    2015-01-01

    Gas hydrate formation in multi phase mixtures containing an aqueous phase (with dissolved salts), reservoir fluid (crude oil) and natural gas phase was investigated by using a standard rocking cell (RC-5) apparatus. The hydrate formation temperature was reduced in the presence of crude oils...... can contribute to the safe operation of sub sea pipelines in the oil and gas industry....

  17. Inhibition of adipose triglyceride lipase (ATGL) by the putative tumor suppressor G0S2 or a small molecule inhibitor attenuates the growth of cancer cells.

    Science.gov (United States)

    Zagani, Rachid; El-Assaad, Wissal; Gamache, Isabelle; Teodoro, Jose G

    2015-09-29

    The G0/G1 switch gene 2 (G0S2) is methylated and silenced in a wide range of human cancers. The protein encoded by G0S2 is an endogenous inhibitor of lipid catabolism that directly binds adipose triglyceride lipase (ATGL). ATGL is the rate-limiting step in triglyceride metabolism. Although the G0S2 gene is silenced in cancer, the impact of ATGL in the growth and survival of cancer cells has never been addressed. Here we show that ectopic expression of G0S2 in non-small cell lung carcinomas (NSCL) inhibits triglyceride catabolism and results in lower cell growth. Similarly, knockdown of ATGL increased triglyceride levels, attenuated cell growth and promoted apoptosis. Conversely, knockdown of endogenous G0S2 enhanced the growth and invasiveness of cancer cells. G0S2 is strongly induced in acute promyelocytic leukemia (APL) cells in response to all trans retinoic acid (ATRA) and we show that inhibition of ATGL in these cells by G0S2 is required for efficacy of ATRA treatment. Our data uncover a novel tumor suppressor mechanism by which G0S2 directly inhibits activity of a key intracellular lipase. Our results suggest that elevated ATGL activity may be a general property of many cancer types and potentially represents a novel target for chemotherapy.

  18. Growth arrest specific protein (GAS) 6

    DEFF Research Database (Denmark)

    Haase, T N; Rasmussen, Morten; Jaksch, C A M

    2013-01-01

    using RNA microarray and quantitative PCR. The role of a differentially expressed gene, growth arrest specific protein 6 (GAS6), was evaluated in vitro using neonatal rat islets. Results The mRNA level of Gas6, known to be mitogenic in other tissues, was reduced in LP offspring. The mRNA content of Mafa...... was increased in LP offspring suggesting an early maturation of beta cells. When applied in vitro, GAS6 increased proliferation of neonatal pancreatic beta cells, while reducing glucose-stimulated insulin secretion without changing the total insulin content of the islets. In addition, GAS6 decreased the m......RNA content of Mafa. Conclusions/interpretation We propose a role for GAS6 in the regulation of pancreatic beta cells in the critical period around the time of birth. Our results support the hypothesis that the reduced beta cell mass seen in LP offspring is caused by a change in the intra-uterine environment...

  19. MOCVD waste gas treatment

    International Nuclear Information System (INIS)

    Geelen, A. van; Bink, P.H.M.; Giling, L.J.

    1993-01-01

    A large scale production of GaAs based solar cells with MOCVD will give rise to a considerable use of arsine. Therefore a gas treatment system is needed to convert the waste gases into less toxic compounds. In this study seven different gas treatment systems for MOCVD are compared by quantifying the environmental aspects. The systems are divided in wet systems, adsorption systems and thermal systems. The smallest amount of waste is produced by adsorption and thermal systems. Adsorption systems use the smallest amount of energy. The amount of primary materials used for the equipment varies per system. All systems are safe, but adsorption systems are simplest. At the moment, adsorption systems are probably the best choice from an environmental point of view. Nevertheless thermal systems have some potential advantages which make them interesting for the future

  20. Gas chromatography

    International Nuclear Information System (INIS)

    Cram, S.P.; Risby, T.H.; Field, L.R.; Yu, W.L.

    1980-01-01

    In addition to the published literature for the years 1978 - 79, this review of developments in the field of gas chromatography includes earlier articles of particular significance appearing in foreign journals and the patent literature which was not available at the time of the previous review. The articles cited were selected as presenting the most fundamental developments in theory, methodology, and instrumentation. Some applications are cited if they reflect an advance in the state-of-the-art or have particular relevance to new developments. 1149 references are cited

  1. Natural gas marketing II

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    This book covers all aspects of gas marketing, from the basic regulatory structure to the latest developments in negotiating agreements and locating markets. Topics include: Federal regulation of the gas industry; Fundamentals of gas marketing contracts; FERC actions encouraging competitive markets; Marketing conditions from the pipelines' perspective; State non-utility regulation of natural gas production, transportation, and marketing; Natural gas wellhead agreements and tariffs; Natural gas processing agreements; Effective management of producer's natural gas contracts; Producer-pipeline litigation; Natural gas purchasing from the perspective of industrial gas users; Gas marketing by co-owners: problems of disproportionate sales, gas balancing, and accounting to royalty owners; Alternatives and new directions in marketing

  2. Oils; gas

    Energy Technology Data Exchange (ETDEWEB)

    Day, D T

    1922-09-18

    Oils and gas are obtained from shale or oil-bearing sand by immersing the shale in and passing it through a bath of liquid oil, cracking the oil-soaked shale, and condensing the vapor and using the condensate to replenish the bath, preferably by passing the gases and vapors direct into the oil-bath container. Shale is fed continuously from a hopper to a bath of oil in an inclined chamber, is carried to the outlet by a conveyer, and through cracking tubes to an outlet pipe by conveyers. The gases and vapors escape by the pipe, a part condensing in the chamber and a run-back pipe and replenishing the bath, and the remainder passing through a condensing tower and condenser connected to reservoirs; the gas is further passed through a scrubber and a pipe to the burner of the retort. The oil condensed in the chamber overflows to the reservoir through a pipe provided with an open pipe to prevent siphoning. The conveyers and a valve on the pipe are operated by gearing. The operation may be conducted at reduced, normal, or increased pressure, e.g., 70 lbs. The temperature of the retort should be about 900 to 1400/sup 0/F, that of the inside of the tubes about 550 to 700/sup 0/F, and that of the chamber about 300/sup 0/F. The chamber and pipe may be insulated or artificially cooled.

  3. Inflammatory Response and Barrier Dysfunction by Different e-Cigarette Flavoring Chemicals Identified by Gas Chromatography-Mass Spectrometry in e-Liquids and e-Vapors on Human Lung Epithelial Cells and Fibroblasts.

    Science.gov (United States)

    Gerloff, Janice; Sundar, Isaac K; Freter, Robert; Sekera, Emily R; Friedman, Alan E; Robinson, Risa; Pagano, Todd; Rahman, Irfan

    2017-03-01

    Recent studies suggest that electronic cigarette (e-cig) flavors can be harmful to lung tissue by imposing oxidative stress and inflammatory responses. The potential inflammatory response by lung epithelial cells and fibroblasts exposed to e-cig flavoring chemicals in addition to other risk-anticipated flavor enhancers inhaled by e-cig users is not known. The goal of this study was to evaluate the release of the proinflammatory cytokine (interleukin-8 [IL-8]) and epithelial barrier function in response to different e-cig flavoring chemicals identified in various e-cig e-liquid flavorings and vapors by chemical characterization using gas chromatography-mass spectrometry analysis. Flavorings, such as acetoin (butter), diacetyl, pentanedione, maltol (malt), ortho-vanillin (vanilla), coumarin, and cinnamaldehyde in comparison with tumor necrosis factor alpha (TNFα), were used in this study. Human bronchial epithelial cells (Beas2B), human mucoepidermoid carcinoma epithelial cells (H292), and human lung fibroblasts (HFL-1) were treated with each flavoring chemical for 24 hours. The cells and conditioned media were then collected and analyzed for toxicity (viability %), lung epithelial barrier function, and proinflammatory cytokine IL-8 release. Cell viability was not significantly affected by any of the flavoring chemicals tested at a concentration of 10 μM to 1 mM. Acetoin and diacetyl treatment induced IL-8 release in Beas2B cells. Acetoin- and pentanedione-treated HFL-1 cells produced a differential, but significant response for IL-8 release compared to controls and TNFα. Flavorings, such as ortho-vanillin and maltol, induced IL-8 release in Beas2B cells, but not in H292 cells. Of all the flavoring chemicals tested, acetoin and maltol were more potent inducers of IL-8 release than TNFα in Beas2B and HFL-1 cells. Flavoring chemicals rapidly impaired epithelial barrier function in human bronchial epithelial cells (16-HBE) as measured by electric cell surface

  4. Development of Osaka gas type planar SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Iha, M.; Shiratori, A.; Chikagawa, O. [Murata Mfg. Co., Ltd., Shiga (Japan)] [and others

    1996-12-31

    Osaka Gas Co. has been developing a planar type SOFC (OG type SOFC) which has a suitable structure for stacking. Murata Mfg. Co. has begun to develop the OG type SOFC stack through joint program since 1993. Figure 1 shows OG type cell structure. Because each cell is sustained by cell holders acting air manifold, the load of upper cell is not put on the lower cells. Single cell is composed of 3-layered membrane and LaCrO{sub 3} separator. 5 single cells are mounted on the cell holder, connected with Ni felt electrically, and bonded by glassy material sealant. We call the 5-cell stack a unit. Stacking 13 units, we succeeded 870 W generation in 1993. But the power density was low, 0.11 Wcm{sup -2} because of crack in the electrolyte and gas leakage at some cells.

  5. Gas Transfer in Cellularized Collagen-Membrane Gas Exchange Devices.

    Science.gov (United States)

    Lo, Justin H; Bassett, Erik K; Penson, Elliot J N; Hoganson, David M; Vacanti, Joseph P

    2015-08-01

    Chronic lower respiratory disease is highly prevalent in the United States, and there remains a need for alternatives to lung transplant for patients who progress to end-stage lung disease. Portable or implantable gas oxygenators based on microfluidic technologies can address this need, provided they operate both efficiently and biocompatibly. Incorporating biomimetic materials into such devices can help replicate native gas exchange function and additionally support cellular components. In this work, we have developed microfluidic devices that enable blood gas exchange across ultra-thin collagen membranes (as thin as 2 μm). Endothelial, stromal, and parenchymal cells readily adhere to these membranes, and long-term culture with cellular components results in remodeling, reflected by reduced membrane thickness. Functionally, acellular collagen-membrane lung devices can mediate effective gas exchange up to ∼288 mL/min/m(2) of oxygen and ∼685 mL/min/m(2) of carbon dioxide, approaching the gas exchange efficiency noted in the native lung. Testing several configurations of lung devices to explore various physical parameters of the device design, we concluded that thinner membranes and longer gas exchange distances result in improved hemoglobin saturation and increases in pO2. However, in the design space tested, these effects are relatively small compared to the improvement in overall oxygen and carbon dioxide transfer by increasing the blood flow rate. Finally, devices cultured with endothelial and parenchymal cells achieved similar gas exchange rates compared with acellular devices. Biomimetic blood oxygenator design opens the possibility of creating portable or implantable microfluidic devices that achieve efficient gas transfer while also maintaining physiologic conditions.

  6. Development and test of 2 kW natural gas reformers for high and low temperature PEM fuel cells. Project report 2; Udvikling/afproevning af 2 kW naturgasreformere for hoej- og lavtemperatur PEM-braendselsceller. Projektrapport 2

    Energy Technology Data Exchange (ETDEWEB)

    Wit, J. de [Dansk Gasteknisk Center (Denmark); Bech-Madsen, J. [IRD (Denmark); Bandur, V. [DTU (Denmark); Bartholin, N. [DPS (Denmark)

    2005-11-15

    The use of fuel cells for combined heat and power generation has advantages as regards technology and usability compared to existing CHP technology. Special characteristics for a fuel cell plant are: 1) It can be constructed in modules over a wide power range, 2) The efficiency is significantly independent of size, 3) It is noiseless, 4) A flexible coupling between power and heat production, 5) As there is no movable parts, long service check intervals can be expected, 6) Low emissions. The fuel for fuel cells is hydrogen and optimal utilization and CO{sub 2} reduction will require a 'hydrogen society'. While waiting for a 'hydrogen society' to arise, it is possible to use central or on-site reformers that convert natural gas to hydrogen. There will be some CO{sub 2} emission connected to energy use. The objective of the present project has been development and test of on-site reformers (fuel processors) for hydrogen supply to respectively high and low temperature PEM fuel cells aiming at use in single family houses. Sulphur cleaning, reformers, and lab-scale coupling with fuel cell KV units have been developed and tested during the project, as well as development and test of periphery equipment. (BA)

  7. Gas, gas, gas... discoveries and developments booming worldwide

    International Nuclear Information System (INIS)

    Maxwell, F.

    2000-01-01

    Deep water exploration is yielding more than billion barrel oil fields. Unocal's 3 May discovery of 2-3 Tcf of gas in its Kutei block of Indonesia marks the first major discovery of natural gas in the deep water frontier: Wildcats Gula and Gada were drilled in over 1800 m of water as part of an aggressive search for gas instigated by Unocal last year. The author makes a survey of gas exploration and development throughout the world. (author)

  8. Optical Absorption Spectroscopy for Gas Analysis in Biomass Gasification

    DEFF Research Database (Denmark)

    Grosch, Helge

    important gas species of the low-temperature circulating fluidized bed gasifier. At first, a special gas cell,the hot gas flow cell (HGC), was build up and veried. In this custom-made gas cell, the optical properties, the so-called absorption cross-sections, of the most important sulfur and aromatic...... compounds were determined in laboratory experiments. By means of the laboratory results and spectroscopic databases,the concentrations of the major gas species and the aromatic compounds phenol and naphthalene were determined in extraction and in-situ measurements....

  9. Survey of landfill gas generation potential

    International Nuclear Information System (INIS)

    Gauntlett, W.D.

    1992-09-01

    This project identifies all the landfill sites in each of the 50 states capable of producing 750,000 SCFD of mixed landfill gas for a period of at least 10 years. The study identified 749 landfill sites nationally, with an aggregate gas production rate sufficient to fuel approximately 6000 MW of fuel cell power plants

  10. British Gas plans global gas unit expansion

    International Nuclear Information System (INIS)

    Vielvoye, R.

    1991-01-01

    This paper reports on developing a global gas business, a British Gas plc's strategy for evolving a state owned U.K. gas company to a privatized worldwide oil and gas giant. By 2000, BG's global gas business is expected to provide 20% of its revenues, compared with 40% each from its exploration and production operations and its U.K. gas business. The global gas unit (GGU) plans to meet its targets mainly through acquiring holdings in gas transmission and distribution companies around the world. In the 12 months since GGU was established, it has made two such major acquisitions in this area. BG acquired Consumers Gas Co., Ltd., Ontario, Canada's biggest natural gas distribution company, for $943.5 million. It also took a 10% stake in Catalana de Gas SA, Barcelona, the largest privately owned gas utility in Spain and in terms of number of customers, the fourth largest in western Europe. BG also is targeting additional revenues from developing gas fired cogeneration systems in developing countries with gas reserves but no established transmission and distribution systems

  11. Molten carbonate fuel cell

    Science.gov (United States)

    Kaun, T.D.; Smith, J.L.

    1986-07-08

    A molten electrolyte fuel cell is disclosed with an array of stacked cells and cell enclosures isolating each cell except for access to gas manifolds for the supply of fuel or oxidant gas or the removal of waste gas. The cell enclosures collectively provide an enclosure for the array and effectively avoid the problems of electrolyte migration and the previous need for compression of stack components. The fuel cell further includes an inner housing about and in cooperation with the array enclosure to provide a manifold system with isolated chambers for the supply and removal of gases. An external insulated housing about the inner housing provides thermal isolation to the cell components.

  12. The Spanish gas industry

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    The spanish gas industry has become one of the major actors in the gas sector of the European Economic Community. This paper pictures the spanish gas industry on the basis of a study by Sedigas, the spanish member of the International Gas Union (IGU). The main subjects described are structure of gas companies, natural gas supply, transport and storage, natural gas distribution networks, statistical data on natural gas consumption, manufactured gas and Liquefied Petroleum Gases (LPG) production-consumption in Spain. 7 figs., 10 tabs

  13. Investigating the effects of gas diffusion layer substrate thickness on polymer electrolyte membrane fuel cell performance via synchrotron X-ray radiography

    International Nuclear Information System (INIS)

    Lee, J.; Chevalier, S.; Banerjee, R.; Antonacci, P.; Ge, N.; Yip, R.; Kotaka, T.; Tabuchi, Y.; Bazylak, A.

    2017-01-01

    Synchrotron X-ray radiography was used to visualize the liquid water accumulation in polymer electrolyte membrane (PEM) fuel cells to compare the impact of carbon substrate thickness on water management. A differential fuel cell with an active area of 0.68 cm 2 and rib/channel width of 0.2 mm was custom-made to provide 1-dimensional (1D) conditions over the active area. The fuel cell with the thin substrate (TGP-H-030) outperformed the fuel cell with the thick substrate (TGP-H-060). The fuel cell with the thinner substrate exhibited a higher limiting current density, less liquid water in the microporous layer (MPL)-substrate transition region, and reduced oxygen transport resistance measured through electrochemical impedance spectroscopy (EIS). The compression behaviour of each GDL was also investigated through two consecutive fuel cell assemblies. The pressure in the second assembly was lower than that for the initial assemblies for both GDLs, and this significant change in assembly pressure was more pronounced for the thinner GDL (TGP-H-030). The resulting interfacial contact between the catalyst layer and the GDL was degraded, which manifested in the microscale displacement of fuel cell materials during operation (detected as a negative liquid water thickness). While the thinner GDL provided superior performance, the long term effects of material deformation may exacerbate a heterogeneous distribution of liquid water that could also impact the performance.

  14. Natural gas in India

    International Nuclear Information System (INIS)

    Lefevre, Thierry; Todoc, Jessie L.

    1999-11-01

    Contains Executive Summary and Chapters on: Country background; Overview of the energy sector; Natural gas supply; Natural gas infrastructure; Natural gas infrastructure; Natural gas demand; Outlook-government policy reform and industry development, and Appendices on Global and regional energy and gas trends; Overview of India's investment policy, incentives and regulation; The ENRON Dabhol power project. (Author)

  15. Natural gas trends

    International Nuclear Information System (INIS)

    Anderson, A.

    1991-01-01

    This book provides data on many facets of the natural gas industry. Topics include: Canadian, Mexican; US natural gas reserves and production; Mexican and US natural gas consumption; market conditions for natural gas in the US; and Canadian natural gas exports

  16. Enhanced performance of proton exchange membrane fuel cell by introducing nitrogen-doped CNTs in both catalyst layer and gas diffusion layer

    CSIR Research Space (South Africa)

    Hou, S

    2017-11-01

    Full Text Available The performance of the proton exchange membrane fuel cell (PEMFC) is significantly improved through introducing nitrogen-doped carbon nanotubes (NCNTs) into the catalyst layer (CL) and microporous layer (MPL) of the membrane electrode assembly (MEA...

  17. Cell-specific vacuolar calcium storage mediated by CAX1 regulates apoplastic calcium concentration, gas exchange, and plant productivity in Arabidopsis.

    Science.gov (United States)

    Conn, Simon J; Gilliham, Matthew; Athman, Asmini; Schreiber, Andreas W; Baumann, Ute; Moller, Isabel; Cheng, Ning-Hui; Stancombe, Matthew A; Hirschi, Kendal D; Webb, Alex A R; Burton, Rachel; Kaiser, Brent N; Tyerman, Stephen D; Leigh, Roger A

    2011-01-01

    The physiological role and mechanism of nutrient storage within vacuoles of specific cell types is poorly understood. Transcript profiles from Arabidopsis thaliana leaf cells differing in calcium concentration ([Ca], epidermis 60 mM) were compared using a microarray screen and single-cell quantitative PCR. Three tonoplast-localized Ca(2+) transporters, CAX1 (Ca(2+)/H(+)-antiporter), ACA4, and ACA11 (Ca(2+)-ATPases), were identified as preferentially expressed in Ca-rich mesophyll. Analysis of respective loss-of-function mutants demonstrated that only a mutant that lacked expression of both CAX1 and CAX3, a gene ectopically expressed in leaves upon knockout of CAX1, had reduced mesophyll [Ca]. Reduced capacity for mesophyll Ca accumulation resulted in reduced cell wall extensibility, stomatal aperture, transpiration, CO(2) assimilation, and leaf growth rate; increased transcript abundance of other Ca(2+) transporter genes; altered expression of cell wall-modifying proteins, including members of the pectinmethylesterase, expansin, cellulose synthase, and polygalacturonase families; and higher pectin concentrations and thicker cell walls. We demonstrate that these phenotypes result from altered apoplastic free [Ca(2+)], which is threefold greater in cax1/cax3 than in wild-type plants. We establish CAX1 as a key regulator of apoplastic [Ca(2+)] through compartmentation into mesophyll vacuoles, a mechanism essential for optimal plant function and productivity.

  18. Gas transport during in vitro and in vivo preclinical testing of inert gas therapies

    Directory of Open Access Journals (Sweden)

    Ira Katz

    2016-01-01

    Full Text Available New gas therapies using inert gases such as xenon and argon are being studied, which require in vitro and in vivo preclinical experiments. Examples of the kinetics of gas transport during such experiments are analyzed in this paper. Using analytical and numerical models, we analyze an in vitro experiment for gas transport to a 96 cell well plate and an in vivo delivery to a small animal chamber, where the key processes considered are the wash-in of test gas into an apparatus dead volume, the diffusion of test gas through the liquid media in a well of a cell test plate, and the pharmacokinetics in a rat. In the case of small animals in a chamber, the key variable controlling the kinetics is the chamber wash-in time constant that is a function of the chamber volume and the gas flow rate. For cells covered by a liquid media the diffusion of gas through the liquid media is the dominant mechanism, such that liquid depth and the gas diffusion constant are the key parameters. The key message from these analyses is that the transport of gas during preclinical experiments can be important in determining the true dose as experienced at the site of action in an animal or to a cell.

  19. Gas in Andean countries

    International Nuclear Information System (INIS)

    Campos Pinzon, Rafael

    2000-01-01

    The paper explores aspects of gas integration among Colombia, Venezuela, Ecuador and Peru. A comparison of the GDP is made, gas reserves are provided and the existent nets of gas-pipe are included in Colombia and Venezuela

  20. Gas diffusion electrodes for PEM-fuel cells via in situ-electrodeposition; Gasdiffusionselektroden fuer PEM-Brennstoffzellen durch in situ-Elektrodeposition

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Vivien

    2009-03-16

    Commercial available membrane electrode assemblies are still very expensive, since a high noble metal catalyst loading has to be on the gas diffusion electrodes. The reason is particularly the fact that a high amount of the catalyst particles is not located in the so called three phase zone between ion conducting, electron conducting and reactant phase. In the present work the electrochemical synthesis of catalyst layers with a higher catalyst utilization, i. e. with a higher amount of particles located in the three phase zone has succeeded. Thus gas diffusion electrodes comparable in performance with commercial materials but coated with a lower catalyst loading were obtained. A second objective in this work was the development of an electrocombinatoric setup in which both the combinatoric electrosynthesis as well as the combinatoric analysis of platinum and platinum alloys can be performed. Furthermore different alloys were electrodeposited and electrocombinatorically analyzed with respect to their catalytic activity in the electroreduction of oxygen and the electrooxidation of hydrogen, methanol and ethanol. (orig.)

  1. Design of neural network model-based controller in a fed-batch microbial electrolysis cell reactor for bio-hydrogen gas production

    Science.gov (United States)

    Azwar; Hussain, M. A.; Abdul-Wahab, A. K.; Zanil, M. F.; Mukhlishien

    2018-03-01

    One of major challenge in bio-hydrogen production process by using MEC process is nonlinear and highly complex system. This is mainly due to the presence of microbial interactions and highly complex phenomena in the system. Its complexity makes MEC system difficult to operate and control under optimal conditions. Thus, precise control is required for the MEC reactor, so that the amount of current required to produce hydrogen gas can be controlled according to the composition of the substrate in the reactor. In this work, two schemes for controlling the current and voltage of MEC were evaluated. The controllers evaluated are PID and Inverse neural network (NN) controller. The comparative study has been carried out under optimal condition for the production of bio-hydrogen gas wherein the controller output is based on the correlation of optimal current and voltage to the MEC. Various simulation tests involving multiple set-point changes and disturbances rejection have been evaluated and the performances of both controllers are discussed. The neural network-based controller results in fast response time and less overshoots while the offset effects are minimal. In conclusion, the Inverse neural network (NN)-based controllers provide better control performance for the MEC system compared to the PID controller.

  2. Very high-power electron-beam transport in long gas cells from 10-3 to 103 Torr N2

    International Nuclear Information System (INIS)

    Sanford, T.W.L.

    1994-01-01

    Measurements and analyses show that the 13-TW, pulsed Hermes-III electron beam, with current near the Alfven limit, has two regimes of stable transport: a low-pressure window (between ∼1 and ∼100 mTorr) that is dominated by propagation in the semi-collisionless IFR (ion-focused regime), and a high-pressure window (between ∼1 and ∼100 Torr) that is dominated by propagation in the resistive CDR (collision-dominated regime). Propagation in both regimes (the IFR at early time and the CDR at later time) is observed from ∼10 to ∼100 mTorr. Below ∼1 mTorr, there is insufficient ionization to confine the beam. As the pressure increases, two-stream instabilities terminate IFR propagation earlier in time. Above 10 mTorr, this instability is sufficiently quenched by gas collisions that CDR propagation in the beam body occurs. Above ∼100 mTorr, the gas breaks down too rapidly for a significant IFR pulse to form, and for higher pressures only a single pulse in the CDR is propagated. Between ∼100 mTorr and ∼1 Torr, however, the hollowing instability and lack of magnetic confinement limit CDR propagation, and above ∼100 Torr, the resistive hose instability again degrades propagation

  3. Accelerated proliferation of non-small cell lung cancer cells after induction chemotherapy

    International Nuclear Information System (INIS)

    El Sharouni, S.Y.; Kal, H.B.

    2003-01-01

    Induction chemotherapy of non-small cell lung cancer (NSCLC) stage IIIB with gemcitabine and cisplatin for downstaging the tumour with the aim for further treatment with ionising radiation, is one of the treatments for lung cancer employed. The purpose of this study was to investigate the influence of the waiting time for radiotherapy, i.e. the interval between induction chemotherapy and radiotherapy, on the rate of tumour growth. Interval times between end of chemotherapy and day of diagnostic CT, planning CT and first day of radiotherapy were determined. Increase in tumour volume was measured for 23 patients with NSCLC by measuring the primary tumour dimensions on the diagnostic CT made after induction chemotherapy and on the CT used for radiotherapy planning. Volume doubling times were calculated from the time interval between the two CTs and ratio of the volumes on CT planning and CT diagnostic. The mean time interval between end of chemotherapy and day of diagnostic CT was 16 days, till CT planning 66 days and till first day of radiotherapy 76 (29 - 108) days. Tumour doubling times ranged from 9 to 153 days with a mean of 47 days. This is far less than the mean doubling time of NSCL in untreated patients. This study shows that time interval between chemo- and start of radiotherapy varies between 29 to 108 days. The consequence is fast tumour progression as result of accelerated proliferation: mean tumour-doubling times are decreased by a factor of 2 to 4. The gain obtained with induction chemotherapy with regard to volume reduction was practically lost in the waiting time for radiotherapy. We recommend diminishing the time interval between chemo- and radiotherapy to as short as possible

  4. Coalbed gas development

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This book includes: Overview of coalbed gas development; Coalbed gas development in the West Coalbed gas development on Indian lands; Multi-mineral development conflicts; Statutory solutions to ownership disputes; State and local regulation; Environmental regulations; Status of the section 29 tax credit extension; Using the section 29 credit; Leasing coalbed gas prospects; Coalbed gas joint operating agreements and Purchase and sale agreements for coalbed gas properties

  5. Could 3-D conformal radiotherapy improve the overall survival for non-small cell lung cancer?

    International Nuclear Information System (INIS)

    Giraud, P.; Helfre, S.; Lavole, A.; Rosenwald, J.C.; Cosset, J.M.

    2002-01-01

    The conformal radiotherapy approach, three-dimensional conformal radiotherapy (3DCRT) and intensity-modulated radiotherapy (IMRT), is based on modern imaging modalities, efficient 3-D treatment planning systems, sophisticated immobilization devices and demanding quality assurance and treatment verification. The main goal of conformal radiotherapy is to ensure a high dose distribution tailored to the limits of the target volume while reducing exposure of healthy tissues. These techniques would then allow a further dose escalation increasing local control and survival. Non-small cell lung cancer (NSCLC) is one of the most difficult malignant tumors to be treated. It combines geometrical difficulties due to respiratory motion, and number of low tolerance neighboring organs, and dosimetric difficulties because of the presence of huge inhomogeneities. This localization is an attractive and ambitious example for the evaluation of new techniques. However, the published clinical reports in the last years described very heterogeneous techniques and, in the absence of prospective randomized trials, it is somewhat difficult at present to evaluate the real benefits drawn from those conformal radiotherapy techniques. After reviewing the rationale for 3DCRT for NSCLC, this paper will describe the main studies of 3DCRT, in order to evaluate its impact on lung cancer treatment Then the current state-of-the-art of IMRT and the last technical and therapeutic innovations in NSCL will be discussed. (authors)

  6. Comparative analysis between two systems to generate electric energy for isolated community in the interior of the Amazon state: fuel cells with natural gas reformer versus diesel generation; Analise comparativa entre dois sistemas de geracao de energia eletrica para a comunidade isolada no interior do estado do Amazonas: celula a combustivel com reformador para gas natural versus gerador diesel

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Paula Duarte; Bergamini, Cristiane Peres; Camargo, Joao Carlos; Lopes, Daniel Gabriel [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Fac. de Engenharia Mecanica; Esteves, Gheisa Roberta Telles [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Nucleo de Pesquisas e Estudos Ambientais; Silva, Ennio Peres da Silva [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Inst. de Fisica Gleb Wataghin

    2004-07-01

    Although great part of the domestic territory is already supplied with electric energy, still there are many regions where the system is precarious or nonexistent, generically called isolated communities. In the majority of the cases these communities are supplied with Diesel oil generators and the substitution of this fuel for available alternative energy in the localities has been object of study of some institutions of research spread throughout the country. Currently, the use of fuel cells has been strongly argued in the generation of electric energy associated with the local energy necessity, from the use of a regional fuel and this is due to the high efficiency of allied energy conversion to the low ambient impacts that this equipment offers. Most of the different types of fuel cells use hydrogen as a fuel to produce electricity, and it is extracted from renewable or non-renewable sources of energy. Then, the article has the objective of comparing in first analysis the energy efficiency and the cost between the two systems: the ones used currently in the great majority of the isolated communities, constituted of a Diesel engine-generator system, with Natural Gas Reformer System/ Purifier of Hydrogen/ Fuel Cell/ and to analyze if such project presents characteristics that qualifies it to get the carbon credits proposed in the Mechanism of Clean Development. (author)

  7. 75 FR 42432 - Northern Natural Gas Company, Southern Natural Gas Company, Florida Gas Transmission Company, LLC...

    Science.gov (United States)

    2010-07-21

    ... Natural Gas Company, Southern Natural Gas Company, Florida Gas Transmission Company, LLC, Transcontinental... abandonment of facilities by Northern Natural Gas Company, Southern Natural Gas Company, Florida Gas... resources, fisheries, and wetlands; Cultural resources; Vegetation and wildlife; Endangered and threatened...

  8. Thermal conductivity of a graphite bipolar plate (BPP) and its thermal contact resistance with fuel cell gas diffusion layers: Effect of compression, PTFE, micro porous layer (MPL), BPP out-of-flatness and cyclic load

    Science.gov (United States)

    Sadeghifar, Hamidreza; Djilali, Ned; Bahrami, Majid

    2015-01-01

    This paper reports on measurements of thermal conductivity of a graphite bipolar plate (BPP) as a function of temperature and its thermal contact resistance (TCR) with treated and untreated gas diffusion layers (GDLs). The thermal conductivity of the BPP decreases with temperature and its thermal contact resistance with GDLs, which has been overlooked in the literature, is found to be dominant over a relatively wide range of compression. The effects of PTFE loading, micro porous layer (MPL), compression, and BPP out-of-flatness are also investigated experimentally. It is found that high PTFE loadings, MPL and even small BPP out-of-flatness increase the BPP-GDL thermal contact resistance dramatically. The paper also presents the effect of cyclic load on the total resistance of a GDL-BPP assembly, which sheds light on the behavior of these materials under operating conditions in polymer electrolyte membrane fuel cells.

  9. Fuel cell electric vehicle as a power plant and SOFC as a natural gas reformer : An exergy analysis of different system designs

    NARCIS (Netherlands)

    Fernandes, A.A.; Woudstra, T.; van Wijk, A.J.M.; Verhoef, L.A.; Purushothaman Vellayani, A.

    2016-01-01

    Delft University of Technology, under its "Green Village" programme, has an initiative to build a power plant (car parking lot) based on the fuel cells used in vehicles for motive power. It is a trigeneration system capable of producing electricity, heat, and hydrogen. It comprises three main

  10. Noble gas magnetic resonator

    Science.gov (United States)

    Walker, Thad Gilbert; Lancor, Brian Robert; Wyllie, Robert

    2014-04-15

    Precise measurements of a precessional rate of noble gas in a magnetic field is obtained by constraining the time averaged direction of the spins of a stimulating alkali gas to lie in a plane transverse to the magnetic field. In this way, the magnetic field of the alkali gas does not provide a net contribution to the precessional rate of the noble gas.

  11. unconventional natural gas reservoirs

    International Nuclear Information System (INIS)

    Correa G, Tomas F; Osorio, Nelson; Restrepo R, Dora P

    2009-01-01

    This work is an exploration about different unconventional gas reservoirs worldwide: coal bed methane, tight gas, shale gas and gas hydrate? describing aspects such as definition, reserves, production methods, environmental issues and economics. The overview also mentioned preliminary studies about these sources in Colombia.

  12. Future of gas

    International Nuclear Information System (INIS)

    Forbes, A.; Widdershoven, C.; Nicola, S.; Cragg, C.

    2009-01-01

    Two articles and two columns in this section on the future of natural gas. In the first article attention is paid to the possibility that large natural gas producers are setting up a cartel a la OPEC. Most experts argue that the structure of gas markets makes the gas business much less amenable to cartelisation than the oil business. If that is true, why are so many people in the gas industry afraid of a gas cartel? The second article focuses on the future role of North Africa in the supply of natural gas

  13. Vancouver Island gas supply

    International Nuclear Information System (INIS)

    Des Brisay, C.

    2005-01-01

    Terasen Gas is pursuing alternatives for the supply of additional natural gas capacity to Vancouver Island. Its subsidiary, Terasen Gas (Vancouver Island) Inc. (TGVI), is responding to the need for delivery of increased gas supply and, is supporting plans for new gas-fired power generation on Vancouver Island. TGVI's proposal for new natural gas capacity involves a combination of compression and pipeline loops as well as the addition of a storage facility for liquefied natural gas (LNG) at Mt. Hayes to help manage price volatility. This presentation outlined the objectives and components of the resource planning process, including demand forecast scenarios and the preferred infrastructure options. tabs., figs

  14. FY 2000 research cooperation project on the research cooperation for the commercialization of the regional adaptation type photovoltaic power generation system, etc. Research cooperation for the commercialization of the methane fermentation gas fuel cell power generation system; 2000 nendo kenkyu kyoryoku jigyo. Chiiki tekigogata taiyoko hatsuden system to no jitsuyoka ni kansuru kenkyu kyoryoku (Metan hakko gas nenryo denchi hatsuden system no jitsuyoka ni kansuru kenkyu kyoryoku)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    Research cooperation for the commercialization of methane fermentation gas fuel cell power generation system was made in a stock farm in Guangzhou city, China, and the FY 2000 results were summed up. In the project, the methane fermentation gas is recovered from animal faces, and a power generation system by fuel cell using the gas as fuel is constructed, and at the same time the waste is made compost and used as manure. In this fiscal year, the starting ceremony was made at the stock farm in Guangzhou city in June, and the main body of fuel cells was carried in and assembled. The trial operation of the system was successfully made in March 2001. At the same time, survey of the waste water from the farm and methane fermentation was made with accuracy. Survey was further made of the actual state of the recent energy supply/demand and the present situation of renewable energy as measures taken for non-electrification areas and environmental problems. As a result, the importance of further cooperation with the China side was emphasized in terms of the securing of animals/faces, optimum methane fermentation/recovery from animal faces, optimization of electric power of the area and environmental response, etc. (NEDO)

  15. Evaluation of in-situ fatty acid extraction protocols for the analysis of staphylococcal cell membrane associated fatty acids by gas chromatography.

    Science.gov (United States)

    Crompton, Marcus J; Dunstan, R Hugh

    2018-05-01

    The composition and integrity of the bacterial cytoplasmic membrane is critical to the survival of staphylococci in dynamic environments and it is important to investigate how the cell membrane responds to changes in the environmental conditions. The staphylococcal membrane differs from eukaryotic and many other bacterial cell membranes by having a high abundance of branch fatty acids and relatively few unsaturated fatty acids. The range of available methods for extraction and efficient analyses of staphylococcal fatty acids was initially appraised to identify the best potential procedures for appraisal. Staphylococcus aureus subsp. aureus Rosenbach (ATCC® 29213) was grown under optimal conditions to generate a cell biomass to compare the efficiencies of three approaches to extract and prepare methyl esters of the membrane fatty acids: (1) acidic direct transesterification of lipids, (2) modified basic direct transesterification of membrane lipids with adjusted reaction times and temperatures, and (3) base catalysed hydrolysis followed by acid catalysed esterification in two separate chemical reactions (MIDI process). All methods were able to extract fatty acids from the cell mass effectively where these lipids represented approximately 5% of the cellular dry mass. The acidic transesterification method had the least number of steps, the lowest coefficient of variation at 6.7% and good resistance to tolerating water. Basic transesterification was the least accurate method showing the highest coefficient of variation (26%). The MIDI method showed good recoveries, but had twice the number of steps and a coefficient of variation of 16%. It was also found that there was no need to use an anti-oxidant such as BHT for the protection of polyunsaturated fatty acids when the GC-MS injection liner was clean. It was concluded that the acidic transesterification procedures formed the most efficient and reproducible method for the analyses of staphylococcal membrane fatty acids

  16. cGAS Conducts Micronuclei DNA Surveillance.

    Science.gov (United States)

    de Oliveira Mann, Carina C; Kranzusch, Philip J

    2017-10-01

    DNA damage elicits a potent proinflammatory immune response. A collection of four papers now reveals that micronuclear DNA is a new cell intrinsic immunostimulatory molecule, and that accumulation of the immune sensor cyclic GMP-AMP synthase (cGAS) in micronuclei leads to a cell-cycle-dependent proinflammatory response following DNA damage. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Natural gas monthly

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-01-01

    The Natural Gas Monthly highlights activities, events, and analyses of interest to public and private sector organizations associated with the natural gas industry. Volume and price data are presented each month for natural gas production, distribution, consumption, and interstate pipeline activities. Producer-related activities and underground storage data are also reported. From time to time, the Natural Gas Monthly features articles designed to assist readers in using and interpreting natural gas information.

  18. Worldwide gas marketing

    International Nuclear Information System (INIS)

    Carson, M.M.

    1994-01-01

    Natural gas is an important source of energy throughout the world due to its availability and clean burning characteristics. From liquefied natural gas being shipped via tanker from Alaska to Japan, to natural gas via pipeline from Canada to the US, to inter-country natural gas shipment within the European continent, natural gas continues to expand and justify its place of honor in the world energy picture

  19. Wet Gas Airfoil Analyses

    OpenAIRE

    Larsen, Tarjei Thorrud

    2011-01-01

    Subsea wet gas compression renders new possibilities for cost savings and enhanced gas recovery on existing gas wells. Technology like this opens to make traditional offshore processing plants redundant. With new technology, follows new challenges. Multiphase flows is regarded as a complex field of study, and increased knowledge on the fundamental mechanisms regarding wet gas flow is of paramount importance to the efficiency and stability of the wet gas compressor. The scope of this work was ...

  20. Green gas in the natural gas network

    International Nuclear Information System (INIS)

    Bruinsma, B.

    2007-09-01

    The aim of this study is to map the technical, economic and organizational options and limitations of feeding biogas back into the natural gas grid by means of regional co-digestion. Emphasis is put on feeding back into the natural gas grid, analogous to a comparable situation in a number of landfill gas projects. This report first provides insight into the energetic potential of co-digestion. Next several landfill gas projects are examined that feed back into the natural gas grid. After that the political and policy-related issues and preconditions for feeding back biogas from co-digestion are discussed, including the technical and economic aspects. Finally, a picture is painted of the future potential of green gas. [mk] [nl