Sample records for redox flow cell

  1. Membraneless Vanadium Redox Fuel Cell Using Laminar Flow Rosaria Ferrigno, Abraham D. Stroock, Thomas D. Clark, Michael Mayer, and

    E-Print Network [OSTI]

    Prentiss, Mara

    Membraneless Vanadium Redox Fuel Cell Using Laminar Flow Rosaria Ferrigno, Abraham D. Stroock This communication describes a small redox fuel cell fabricated using a design that omits the membrane normally used this concept by operating a millimeter-scale redox fuel cell that uses the redox couples V(V)/V(IV) (cathodic

  2. Cascade redox flow battery systems

    DOE Patents [OSTI]

    Horne, Craig R.; Kinoshita, Kim; Hickey, Darren B.; Sha, Jay E.; Bose, Deepak

    2014-07-22T23:59:59.000Z

    A reduction/oxidation ("redox") flow battery system includes a series of electrochemical cells arranged in a cascade, whereby liquid electrolyte reacts in a first electrochemical cell (or group of cells) before being directed into a second cell (or group of cells) where it reacts before being directed to subsequent cells. The cascade includes 2 to n stages, each stage having one or more electrochemical cells. During a charge reaction, electrolyte entering a first stage will have a lower state-of-charge than electrolyte entering the nth stage. In some embodiments, cell components and/or characteristics may be configured based on a state-of-charge of electrolytes expected at each cascade stage. Such engineered cascades provide redox flow battery systems with higher energy efficiency over a broader range of current density than prior art arrangements.

  3. Redox Flow Batteries, a Review

    SciTech Connect (OSTI)

    U. Tennessee Knoxville; U. Texas Austin; McGill U; Weber, Adam Z.; Mench, Matthew M.; Meyers, Jeremy P.; Ross, Philip N.; Gostick, Jeffrey T.; Liu, Qinghua

    2011-07-15T23:59:59.000Z

    Redox flow batteries are enjoying a renaissance due to their ability to store large amounts of electrical energy relatively cheaply and efficiently. In this review, we examine the components of redox flow batteries with a focus on understanding the underlying physical processes. The various transport and kinetic phenomena are discussed along with the most common redox couples.

  4. Optimization of electrode characteristics for the Br?/H? redox flow cell

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Tucker, Michael C.; Cho, Kyu Taek; Weber, Adam Z.; Lin, Guangyu; Van Nguyen, Trung

    2015-01-01T23:59:59.000Z

    The Br?/H? redox flow cell shows promise as a high-power, low-cost energy storage device. The effect of various aspects of material selection, processing, and assembly of electrodes on the operation, performance, and efficiency of the system is determined. In particular, (+) electrode thickness, cell compression, hydrogen pressure, and (–) electrode architecture are investigated. Increasing hydrogen pressure and depositing the (–) catalyst layer on the membrane instead of on the carbon-paper backing layers have a large positive impact on performance, enabling a limiting current density above 2 A cm-2 and a peak power density of 1.4 W cm-2. Maximum energy efficiencymore »of 79% is achieved. In addition, the root cause of limiting-current behavior in this system is elucidated, where it is found that Br? reversibly adsorbs at the Pt (–) electrode for potentials exceeding a critical value, and the extent of Br? coverage is potential-dependent. This phenomenon limits maximum cell current density and must be addressed in system modeling and design. These findings are expected to lower system cost and enable higher efficiency.« less

  5. Optimization of electrode characteristics for the Br2/H2 redox flow cell

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Tucker, Michael C.; Cho, Kyu Taek; Weber, Adam Z.; Lin, Guangyu; Nguyen, Trung V.

    2014-10-01T23:59:59.000Z

    The Br2/H2 redox flow cell shows promise as a high-power, low-cost energy storage device. The effect of various aspects of material selection, processing, and assembly of electrodes on the operation, performance, and efficiency of the system is determined. In particular, (+) electrode thickness, cell compression, hydrogen pressure, and (?) electrode architecture are investigated. Increasing hydrogen pressure and depositing the (?) catalyst layer on the membrane instead of on the carbon paper backing layers have a large positive impact on performance, enabling a limiting current density above 2 A cm?2 and a peak power density of 1.4 W cm?2. Maximum energymore »efficiency of 79 % is achieved. In addition, the root cause of limiting-current behavior in this system is elucidated, where it is found that Br? reversibly adsorbs at the Pt (?) electrode for potentials exceeding a critical value, and the extent of Br? coverage is potential-dependent. This phenomenon limits maximum cell current density and must be addressed in system modeling and design. These findings are expected to lower system cost and enable higher efficiency.« less

  6. Optimization of electrode characteristics for the Br2/H2 redox flow cell

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Tucker, Michael C.; Cho, Kyu Taek; Weber, Adam Z.; Lin, Guangyu; Nguyen, Trung V.

    2014-10-01T23:59:59.000Z

    The Br2/H2 redox flow cell shows promise as a high-power, low-cost energy storage device. The effect of various aspects of material selection, processing, and assembly of electrodes on the operation, performance, and efficiency of the system is determined. In particular, (+) electrode thickness, cell compression, hydrogen pressure, and (?) electrode architecture are investigated. Increasing hydrogen pressure and depositing the (?) catalyst layer on the membrane instead of on the carbon paper backing layers have a large positive impact on performance, enabling a limiting current density above 2 A cm?2 and a peak power density of 1.4 W cm?2. Maximum energy efficiency of 79 % is achieved. In addition, the root cause of limiting-current behavior in this system is elucidated, where it is found that Br? reversibly adsorbs at the Pt (?) electrode for potentials exceeding a critical value, and the extent of Br? coverage is potential-dependent. This phenomenon limits maximum cell current density and must be addressed in system modeling and design. These findings are expected to lower system cost and enable higher efficiency.

  7. Rebalancing electrolytes in redox flow battery systems

    DOE Patents [OSTI]

    Chang, On Kok; Pham, Ai Quoc

    2014-12-23T23:59:59.000Z

    Embodiments of redox flow battery rebalancing systems include a system for reacting an unbalanced flow battery electrolyte with a rebalance electrolyte in a first reaction cell. In some embodiments, the rebalance electrolyte may contain ferrous iron (Fe.sup.2+) which may be oxidized to ferric iron (Fe.sup.3+) in the first reaction cell. The reducing ability of the rebalance reactant may be restored in a second rebalance cell that is configured to reduce the ferric iron in the rebalance electrolyte back into ferrous iron through a reaction with metallic iron.

  8. Fact Sheet: Vanadium Redox Flow Batteries (October 2012) | Department...

    Energy Savers [EERE]

    Batteries (October 2012) Fact Sheet: Vanadium Redox Flow Batteries (October 2012) DOE's Energy Storage Program is funding research to develop next-generation vanadium redox flow...

  9. Redox Flow Batteries: An Engineering Perspective

    SciTech Connect (OSTI)

    Chalamala, Babu R.; Soundappan, Thiagarajan; Fisher, Graham R.; Anstey, Mitchell A.; Viswanathan, Vilayanur V.; Perry, Mike L.

    2014-10-01T23:59:59.000Z

    Redox flow batteries are well suited to provide modular and scalable energy storage systems for a wide range of energy storage applications. In this paper, we review the development of redox flow battery technology including recent advances in new redox active materials and systems. We discuss cost, performance, and reliability metrics that are critical for deployment of large flow battery systems. The technology, while relatively young, has the potential for significant improvement through reduced materials costs, improved energy and power efficiency, and significant reduction in the overall system cost.

  10. High energy density redox flow device

    DOE Patents [OSTI]

    Chiang, Yet-Ming; Carter, W. Craig; Ho, Bryan Y; Duduta, Mihai; Limthongkul, Pimpa

    2014-05-13T23:59:59.000Z

    Redox flow devices are described in which at least one of the positive electrode or negative electrode-active materials is a semi-solid or is a condensed ion-storing electroactive material, and in which at least one of the electrode-active materials is transported to and from an assembly at which the electrochemical reaction occurs, producing electrical energy. The electronic conductivity of the semi-solid is increased by the addition of conductive particles to suspensions and/or via the surface modification of the solid in semi-solids (e.g., by coating the solid with a more electron conductive coating material to increase the power of the device). High energy density and high power redox flow devices are disclosed. The redox flow devices described herein can also include one or more inventive design features. In addition, inventive chemistries for use in redox flow devices are also described.

  11. High energy density redox flow device

    DOE Patents [OSTI]

    Chiang, Yet-Ming; Carter, William Craig; Duduta, Mihai; Limthongkul, Pimpa

    2014-05-13T23:59:59.000Z

    Redox flow devices are described including a positive electrode current collector, a negative electrode current collector, and an ion-permeable membrane separating said positive and negative current collectors, positioned and arranged to define a positive electroactive zone and a negative electroactive zone; wherein at least one of said positive and negative electroactive zone comprises a flowable semi-solid composition comprising ion storage compound particles capable of taking up or releasing said ions during operation of the cell, and wherein the ion storage compound particles have a polydisperse size distribution in which the finest particles present in at least 5 vol % of the total volume, is at least a factor of 5 smaller than the largest particles present in at least 5 vol % of the total volume.

  12. Numerical modeling of an all vanadium redox flow battery.

    SciTech Connect (OSTI)

    Clausen, Jonathan R.; Brunini, Victor E.; Moffat, Harry K.; Martinez, Mario J.

    2014-01-01T23:59:59.000Z

    We develop a capability to simulate reduction-oxidation (redox) flow batteries in the Sierra Multi-Mechanics code base. Specifically, we focus on all-vanadium redox flow batteries; however, the capability is general in implementation and could be adopted to other chemistries. The electrochemical and porous flow models follow those developed in the recent publication by [28]. We review the model implemented in this work and its assumptions, and we show several verification cases including a binary electrolyte, and a battery half-cell. Then, we compare our model implementation with the experimental results shown in [28], with good agreement seen. Next, a sensitivity study is conducted for the major model parameters, which is beneficial in targeting specific features of the redox flow cell for improvement. Lastly, we simulate a three-dimensional version of the flow cell to determine the impact of plenum channels on the performance of the cell. Such channels are frequently seen in experimental designs where the current collector plates are borrowed from fuel cell designs. These designs use a serpentine channel etched into a solid collector plate.

  13. Advanced Redox Flow Batteries for Stationary Electrical Energy Storage

    SciTech Connect (OSTI)

    Li, Liyu; Kim, Soowhan; Xia, Guanguang; Wang, Wei; Yang, Zhenguo

    2012-03-19T23:59:59.000Z

    This report describes the status of the advanced redox flow battery research being performed at Pacific Northwest National Laboratories for the U.S. Department of Energy’s Energy Storage Systems Program. The Quarter 1 of FY2012 Milestone was completed on time. The milestone entails completion of evaluation and optimization of single cell components for the two advanced redox flow battery electrolyte chemistries recently developed at the lab, the all vanadium (V) mixed acid and V-Fe mixed acid solutions. All the single cell components to be used in future kW-scale stacks have been identified and optimized in this quarter, which include solution electrolyte, membrane or separator; carbon felt electrode and bi-polar plate. Varied electrochemical, chemical and physical evaluations were carried out to assist the component screening and optimization. The mechanisms of the battery capacity fading behavior for the all vanadium redox flow and the Fe/V battery were discovered, which allowed us to optimize the related cell operation parameters and continuously operate the system for more than three months without any capacity decay.

  14. Fe-V redox flow batteries

    DOE Patents [OSTI]

    Li, Liyu; Kim, Soowhan; Yang, Zhenguo; Wang, Wei; Zhang, Jianlu; Chen, Baowei; Nie, Zimin; Xia, Guanguang

    2014-07-08T23:59:59.000Z

    A redox flow battery having a supporting solution that includes Cl.sup.- anions is characterized by an anolyte having V.sup.2+ and V.sup.3+ in the supporting solution, a catholyte having Fe.sup.2+ and Fe.sup.3+ in the supporting solution, and a membrane separating the anolyte and the catholyte. The anolyte and catholyte can have V cations and Fe cations, respectively, or the anolyte and catholyte can each contain both V and Fe cations in a mixture. Furthermore, the supporting solution can contain a mixture of SO.sub.4.sup.2- and Cl.sup.- anions.

  15. Paper Offer #: 031CES-216 PlanarArray REDOX Cells and pH Sensors

    E-Print Network [OSTI]

    Kounaves, Samuel P.

    in a see- into, flow-through polycarbonate chamber. A water-tight seal is obtained by using O-rings placed], conductivity sensors [3], REDOX cells [3], and pH sensors. This paper focuses on the development of nine REDOX cells, a conductivity sensor, a temperature #12;attached to the polycarbonatechamber

  16. Iron-sulfide redox flow batteries

    DOE Patents [OSTI]

    Xia, Guan-Guang; Yang, Zhenguo; Li, Liyu; Kim, Soowhan; Liu, Jun; Graff, Gordon L

    2013-12-17T23:59:59.000Z

    Iron-sulfide redox flow battery (RFB) systems can be advantageous for energy storage, particularly when the electrolytes have pH values greater than 6. Such systems can exhibit excellent energy conversion efficiency and stability and can utilize low-cost materials that are relatively safer and more environmentally friendly. One example of an iron-sulfide RFB is characterized by a positive electrolyte that comprises Fe(III) and/or Fe(II) in a positive electrolyte supporting solution, a negative electrolyte that comprises S.sup.2- and/or S in a negative electrolyte supporting solution, and a membrane, or a separator, that separates the positive electrolyte and electrode from the negative electrolyte and electrode.

  17. Recent Progress in Redox Flow Battery Research and Development

    SciTech Connect (OSTI)

    Wang, Wei; Luo, Qingtao; Li, Bin; Wei, Xiaoliang; Li, Liyu; Yang, Zhenguo

    2013-02-20T23:59:59.000Z

    With the increase need to seamlessly integrate the renewable energy with the current grid which itself is evolving into a more intelligent, efficient, and capable electrical power system, it is envisioned that the energy storage system will play a more prominent role in bridging the gap between the current technology and a clean sustainable future in grid reliability and utilization. Redox flow battery technology is leading the way in this perspective in providing a well balanced approach for current challenges. Recent progress in the research and development of redox flow battery technology is reviewed here with a focus on new chemistries and systems.

  18. A Stable Vanadium Redox-Flow Battery with High Energy Density...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Stable Vanadium Redox-Flow Battery with High Energy Density for Large-scale Energy Storage. A Stable Vanadium Redox-Flow Battery with High Energy Density for Large-scale Energy...

  19. Accepted Manuscript Title: Dramatic Performance Gains in Vanadium Redox Flow

    E-Print Network [OSTI]

    Mench, Matthew M.

    ) are a potentially enabling technology for intermittent, renewable energy sources such as wind and solar power [1, for most stationary power uses, the #12;Page 3 of 18 Accepted M anuscript energy density per seAccepted Manuscript Title: Dramatic Performance Gains in Vanadium Redox Flow Batteries Through

  20. Redox flow batteries based on supporting solutions containing chloride

    DOE Patents [OSTI]

    Li, Liyu; Kim, Soowhan; Yang, Zhenguo; Wang, Wei; Zhang, Jianlu; Chen, Baowei; Nie, Zimin; Xia, Guanguang

    2014-01-14T23:59:59.000Z

    Redox flow battery systems having a supporting solution that contains Cl.sup.- ions can exhibit improved performance and characteristics. Furthermore, a supporting solution having mixed SO.sub.4.sup.2- and Cl.sup.- ions can provide increased energy density and improved stability and solubility of one or more of the ionic species in the catholyte and/or anolyte. According to one example, a vanadium-based redox flow battery system is characterized by an anolyte having V.sup.2+ and V.sup.3+ in a supporting solution and a catholyte having V.sup.4+ and V.sup.5+ in a supporting solution. The supporting solution can contain Cl.sup.- ions or a mixture of SO.sub.4.sup.2- and Cl.sup.- ions.

  1. Cost and Performance Model for Redox Flow Batteries

    SciTech Connect (OSTI)

    Viswanathan, Vilayanur V.; Crawford, Aladsair J.; Stephenson, David E.; Kim, Soowhan; Wang, Wei; Li, Bin; Coffey, Greg W.; Thomsen, Edwin C.; Graff, Gordon L.; Balducci, Patrick J.; Kintner-Meyer, Michael CW; Sprenkle, Vincent L.

    2014-02-01T23:59:59.000Z

    A cost model was developed for all vanadium and iron-vanadium redox flow batteries. Electrochemical performance modeling was done to estimate stack performance at various power densities as a function of state of charge. This was supplemented with a shunt current model and a pumping loss model to estimate actual system efficiency. The operating parameters such as power density, flow rates and design parameters such as electrode aspect ratio, electrolyte flow channel dimensions were adjusted to maximize efficiency and minimize capital costs. Detailed cost estimates were obtained from various vendors to calculate cost estimates for present, realistic and optimistic scenarios. The main drivers for cost reduction for various chemistries were identified as a function of the energy to power ratio of the storage system. Levelized cost analysis further guided suitability of various chemistries for different applications.

  2. Anthraquinone with Tailored Structure for Nonaqueous Metal-Organic Redox Flow Battery

    SciTech Connect (OSTI)

    Wang, Wei; Xu, Wu; Cosimbescu, Lelia; Choi, Daiwon; Li, Liyu; Yang, Zhenguo

    2012-06-08T23:59:59.000Z

    A nonaqueous, hybrid metal-organic redox flow battery based on tailored anthraquinone structure is demonstrated to have an energy efficiency of {approx}82% and a specific discharge energy density similar to aqueous redox flow batteries, which is due to the significantly improved solubility of anthraquinone in supporting electrolytes.

  3. Electrochemical investigation of polyhalide ion oxidation-reduction on carbon nanotube electrodes for redox flow batteries

    SciTech Connect (OSTI)

    Shao, Yuyan; Engelhard, Mark H.; Lin, Yuehe

    2009-10-01T23:59:59.000Z

    Polyhalide ions (Br-/BrCl2-) are an important redox couple for redox flow batteries. The oxidation-reduction behavior of polyhalide ions on a carbon nanotube (CNT) electrode has been investigated with cyclic voltammetry and electrochemical impedance spectroscopy. The onset oxidation potential of Br-/BrCl2- is negatively shifted by >100 mV, and the redox current peaks are greatly enhanced on a CNT electrode compared with that on the most widely-used graphite electrode. The reaction resistance of the redox couple (Br-/BrCl2-) is decreased on a CNT electrode. The redox reversibility is increased on a CNT electrode even though it still needs further improvement. CNT is a promising electrode material for redox flow batteries.

  4. Nitrogen-doped mesoporous carbon for energy storage in vanadium redox flow batteries

    SciTech Connect (OSTI)

    Shao, Yuyan; Wang, Xiqing; Engelhard, Mark H.; Wang, Chong M.; Dai, Sheng; Liu, Jun; Yang, Zhenguo; Lin, Yuehe

    2010-03-22T23:59:59.000Z

    We demonstrate a novel electrode material?nitrogen-doped mesoporous carbon (NMC)?for vanadium redox flow batteries. Mesoporous carbon (MC) is prepared using a soft-template method and doped with nitrogen by heat-treating MC in NH3. NMC is characterized with X-ray photoelectron spectroscopy and transmission electron microscopy. The redox reaction of VO2+/VO2+ is characterized with cyclic voltammetry and electrochemical impedance spectroscopy. The electrocatalytic kinetics of the redox couple VO2+/VO2+ is significantly enhanced on NMC electrode compared with MC and graphite electrodes. The reversibility of the redox couple VO2+/VO2+ is greatly improved on NMC (0.61 for NMC vs. 0.34 for graphite). Nitrogen doping facilitates the electron transfer on the electrode/electrolyte interface for both oxidation and reduction processes. NMC is a promising electrode material for redox flow batteries.

  5. TEMPO-based Catholyte for High Energy Density Nonaqueous Redox Flow Batteries

    SciTech Connect (OSTI)

    Wei, Xiaoliang; Xu, Wu; Vijayakumar, M.; Cosimbescu, Lelia; Liu, Tianbiao L.; Sprenkle, Vincent L.; Wang, Wei

    2014-12-03T23:59:59.000Z

    We will present a novel design lithium-organic non-aqueous redox flow battery based on a TEMPO catholyte. This RFB produced desired electrochemical performance exceeding most of the currently reported nonaqueous RFB systems.

  6. Towards High-Performance Nonaqueous Redox Flow Electrolyte through Ionic Modification of Active Species

    SciTech Connect (OSTI)

    Wei, Xiaoliang; Cosimbescu, Lelia; Xu, Wu; Hu, Jian Z.; Vijayakumar, M.; Feng, Ju; Hu, Mary Y.; Deng, Xuchu; Xiao, Jie; Liu, Jun; Sprenkle, Vincent L.; Wang, Wei

    2015-01-01T23:59:59.000Z

    We will present a novel design lithium-organic non-aqueous redox flow battery based on a modified ferrocene catholyte. This RFB produced desired electrochemical performance exceeding most of the currently reported nonaqueous RFB systems.

  7. Nanorod Niobium Oxide as Powerful Catalysts for an All Vanadium Redox Flow Battery

    SciTech Connect (OSTI)

    Li, Bin; Gu, Meng; Nie, Zimin; Wei, Xiaoliang; Wang, Chong M.; Sprenkle, Vincent L.; Wang, Wei

    2014-01-01T23:59:59.000Z

    Graphite felts (GFs), as typical electrode materials for all vanadium redox flow batteries (VRBs), limit the cell operation to low current density because of their poor kinetic reversibility and electrochemical activity. Here, in order to address this issue we report an electrocatalyst, Nb2O5, decorating the surface of GFs to reduce the activation barrier for redox conversion. Nb2O5 nanofibers with monoclinic phases are synthesized by hydrothermal method and deposited on GFs, which is confirmed to have catalytic effects towards redox couples of V(II)/V(III) at the negative side and V(IV)/V(V) at the positive side, and thus applied in both electrodes of VRB cells. Due to the low conductivity of Nb2O5, the performance of electrodes heavily depends on the nano size and uniform distribution of catalysts on GFs surfaces. The addition of the water-soluble compounds containing W element into the precursor solutions facilitates the precipitation of nanofibers on the GFs. Accordingly, an optimal amount of W-doped Nb2O5 nanofibers with weaker agglomeration and better distribution on GFs surfaces are obtained, leading to significant improvement of the electrochemical performances of VRB cells particularly under the high power operation. The corresponding energy efficiency is enhanced by 10.7 % under the operation of high charge/discharge current density (150 mA•cm-2) owing to faster charge transfer as compared with that without catalysts. These results suggest that Nb2O5 based nanofibers-decorating GFs hold great promise as high-performance electrodes for VRB applications.

  8. Lithium borate cluster salts as novel redox shuttles for overcharge protection of lithium-ion cells.

    SciTech Connect (OSTI)

    Chen, Z.; Liu, J.; Jansen, A. N.; Casteel, B.; Amine, K.; GirishKumar, G.; Air Products and Chemicals, Inc.

    2010-01-01T23:59:59.000Z

    Redox shuttle is a promising mechanism for intrinsic overcharge protection in lithium-ion cells and batteries. Two lithium borate cluster salts are reported to function as both the main salt for a nonaqueous electrolyte and the redox shuttle for overcharge protection. Lithium borate cluster salts with a tunable redox potential are promising candidates for overcharge protection for most positive electrodes in state-of-the-art lithium-ion cells.

  9. Nickel Phase Wettability and YSZ Redox Fracture Percolation in Solid Oxide Fuel Cell Anodes

    E-Print Network [OSTI]

    Petta, Jason

    Nickel Phase Wettability and YSZ Redox Fracture Percolation in Solid Oxide Fuel Cell Anodes Alex and Aerospace Engineering Background Solid oxide fuel cells lose mechanical stability and functionality when

  10. Live Cell Chemical Profiling of Temporal Redox Dynamics in a Photoautotrophic Cyanobacterium

    SciTech Connect (OSTI)

    Sadler, Natalie C.; Melnicki, Matthew R.; Serres, Margrethe H.; Merkley, Eric D.; Chrisler, William B.; Hill, Eric A.; Romine, Margaret F.; Kim, Sangtae; Zink, Erika M.; Datta, Suchitra; Smith, Richard D.; Beliaev, Alex S.; Konopka, Allan; Wright, Aaron T.

    2014-01-01T23:59:59.000Z

    Protein reduction-oxidation (redox) modification is an important mechanism that allows microorganisms to sense environmental changes and initiate cellular responses. We have developed a quantitative chemical probe approach for live cell labeling of proteins that are sensitive to redox modifications. We utilize this in vivo strategy to identify 176 proteins undergoing ~5-10 fold dynamic redox change in response to nutrient limitation and subsequent replenishment in the photoautotrophic cyanobacterium, Synechococcus sp. PCC 7002. We detect redox changes in as little as 30 seconds after nutrient perturbation, and oscillations in reduction and oxidation for 60 minutes following the perturbation. Many of the proteins undergoing dynamic redox transformations participate in the major components for the production (photosystems and electron transport chains) or consumption (Calvin-Benson cycle and protein synthesis) of reductant and/or energy in photosynthetic organisms. Thus, our in vivo approach reveals new redox-susceptible proteins, in addition to validating those previously identified in vitro.

  11. Bismuth Nanoparticle Decorating Graphite Felt as a High-Performance Electrode for an All-Vanadium Redox Flow Battery

    SciTech Connect (OSTI)

    Li, Bin; Gu, Meng; Nie, Zimin; Shao, Yuyan; Luo, Qingtao; Wei, Xiaoliang; Li, Xiaolin; Xiao, Jie; Wang, Chong M.; Sprenkle, Vincent L.; Wang, Wei

    2013-02-04T23:59:59.000Z

    The selection of electrode materials plays a great role in improving performances of all vanadium redox flow batteries (VRBs). Low-cost graphite felt (GF) as traditional electrode material has to be modified to address its issue of low electrocatalytic activity. In our paper, low-cost and highly conductive bismuth nanoparticles, as a powerful alternative electrocatalyst to noble metal, are proposed and synchronously electro-deposited onto the surface of GF while running flow cells employing the electrolytes containing suitable Bi3+. Although bismuth is proved to only take effect on the redox reaction of V(II)/V(III) and present at negative half-cell side, the whole cell electrochemical performances are significantly improved. In particular, the energy efficiency is increased by 11% owing to faster charge transfer as compared with one without Bi at high charge/discharge rate of 150 mA/cm2, which is prone to reduce stack size, thus dramatically reducing the cost. The excellent results show great promise of Bi nano-catalysts in the commercialization of VRBs in terms of product cost as well as electrochemical properties.

  12. all-vanadium redox flow: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Waters Outline: 1. Redox chemistry 2. Redox potential in aquatic systems 3. Eutrophication 4. Water treatment 1. Redox chemistry 15; Principle of equilibration of chemical...

  13. all-uranium redox flow: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Waters Outline: 1. Redox chemistry 2. Redox potential in aquatic systems 3. Eutrophication 4. Water treatment 1. Redox chemistry 15; Principle of equilibration of chemical...

  14. Resolving Losses at the Negative Electrode in All-Vanadium Redox Flow Batteries Using Electrochemical Impedance Spectroscopy

    SciTech Connect (OSTI)

    Sun, Che Nan [ORNL] [ORNL; Delnick, Frank M [ORNL] [ORNL; Aaron, D [University of Tennessee, Knoxville (UTK)] [University of Tennessee, Knoxville (UTK); Mench, Matthew M [ORNL] [ORNL; Zawodzinski, Thomas A [ORNL] [ORNL

    2014-01-01T23:59:59.000Z

    We present an in situ electrochemical technique for the quantitative measurement and resolution of the ohmic, charge transfer and diffusion overvoltages at the negative electrode of an all-vanadium redox flow battery (VRFB) using electrochemical impedance spectroscopy (EIS). The mathematics describing the complex impedance of the V+2/V+3 redox reaction is derived and matches the experimental data. The voltage losses contributed by each process have been resolved and quantified at various flow rates and electrode thicknesses as a function of current density during anodic and cathodic polarization. The diffusion overvoltage was affected strongly by flow rate while the charge transfer and ohmic losses were invariant. On the other hand, adopting a thicker electrode significantly changed both the charge transfer and diffusion losses due to increased surface area. Furthermore, the Tafel plot obtained from the impedance resolved charge transfer overvoltage yielded the geometric exchange current density, anodic and cathodic Tafel slopes (135 5 and 121 5 mV/decade respectively) and corresponding transfer coefficients = 0.45 0.02 and = 0.50 0.02 in an operating cell.

  15. Membrane Separator for Redox Flow Batteries that Utilize Anion Radical Mediators.

    SciTech Connect (OSTI)

    Delnick, Frank M.

    2014-10-01T23:59:59.000Z

    A Na + ion conducting polyethylene oxide membrane is developed for an organic electrolyte redox flow battery that utilizes anion radical mediators. To achieve high specific ionic conductivity, tetraethyleneglycol dimethylether (TEGDME) is used as a plasticizer to reduce crystallinity and increase the free volume of the gel film. This membrane is physically and chemically stable in TEGDME electrolyte that contains highly reactive biphenyl anion radical mediators.

  16. Nitrogen-doped mesoporous carbon for energy storage in vanadium redox flow batteries

    SciTech Connect (OSTI)

    Dai, Sheng [ORNL; Shao, Yuyan [Pacific Northwest National Laboratory (PNNL); Wang, Xiqing [ORNL; Engelhard, Mark H [Pacific Northwest National Laboratory (PNNL); Wang, Congmin [ORNL; Liu, Jun [Pacific Northwest National Laboratory (PNNL); YANG, ZHENGUO [Pacific Northwest National Laboratory (PNNL); Lin, Yuehe [ORNL

    2010-01-01T23:59:59.000Z

    We demonstrate an excellent performance of nitrogen-doped mesoporous carbon (N-MPC) for energy storage in vanadium redox flow batteries. Mesoporous carbon (MPC) is prepared using a soft-template method and doped with nitrogen by heat-treating MPC in NH{sub 3}. N-MPC is characterized with X-ray photoelectron spectroscopy and transmission electron microscopy. The redox reaction of [VO]{sup 2+}/[VO{sub 2}]{sup +} is characterized with cyclic voltammetry and electrochemical impedance spectroscopy. The electrocatalytic kinetics of the redox couple [VO]{sup 2+}/[VO{sub 2}]{sup +} is significantly enhanced on N-MPC electrode compared with MPC and graphite electrodes. The reversibility of the redox couple [VO]{sup 2+}/[VO{sub 2}]{sup +} is greatly improved on N-MPC (0.61 for N-MPC vs. 0.34 for graphite), which is expected to increase the energystorage efficiency of redoxflowbatteries. Nitrogen doping facilitates the electron transfer on electrode/electrolyte interface for both oxidation and reduction processes. N-MPC is a promising material for redoxflowbatteries. This also opens up new and wider applications of nitrogen-doped carbon.

  17. Electrochimica Acta 52 (2007) 49424946 High-performance microfluidic vanadium redox fuel cell

    E-Print Network [OSTI]

    Brolo, Alexandre G.

    2007-01-01T23:59:59.000Z

    vanadium redox fuel cell Erik Kjeanga,c, Brenton T. Proctora,c, Alexandre G. Brolob,c, David A. Harringtonb a new microfluidic fuel cell design with high-surface area porous carbon electrodes and high aspect-effective and rapid fabrication, and would be applicable to most microfluidic fuel cell architectures. © 2007 Elsevier

  18. A New Direction in Dye-Sensitized Solar Cells Redox Mediator Development: In Situ Fine-Tuning of the Cobalt(II)/(III) Redox

    E-Print Network [OSTI]

    A New Direction in Dye-Sensitized Solar Cells Redox Mediator Development: In Situ Fine 3168, Australia *S Supporting Information ABSTRACT: Dye-sensitized solar cells (DSCs) are an attractive to tackle present and future energy challenges. Dye-sensitized solar cells (DSCs) are considered

  19. Short communication All-vanadium redox photoelectrochemical cell: An approach to store

    E-Print Network [OSTI]

    Liu, Fuqiang

    rechargeable batteries [8,9] in PEC energy storage, integrating a hydrogen bromine-embedded Si system and fuel demonstrated combin- ing PEC energy storage with a vanadium redox-flow battery (VRB), a well commercialized demonstrated facile photo- oxidation kinetics of VO2+ by a wide-band-gap TiO2 photoanode, presenting

  20. Proton Gradient Regulation 5-Mediated Cyclic Electron Flow under ATP-or Redox-Limited Conditions: A Study of

    E-Print Network [OSTI]

    Proton Gradient Regulation 5-Mediated Cyclic Electron Flow under ATP- or Redox-Limited Conditions.K.N.) The Chlamydomonas reinhardtii proton gradient regulation5 (Crpgr5) mutant shows phenotypic and functional traits discriminate two pathways for CEF and determine their maximum electron flow rates. The PGR5/proton gradient

  1. Solid polymer electrolyte electrochemical storage cell containing a redox shuttle additive for overcharge protection

    DOE Patents [OSTI]

    Richardson, Thomas J. (Oakland, CA); Ross, Philip N. (Moraga, CA)

    1999-01-01T23:59:59.000Z

    A class of organic redox shuttle additives is described, preferably comprising nitrogen-containing aromatics compounds, which can be used in a high temperature (85.degree. C. or higher) electrochemical storage cell comprising a positive electrode, a negative electrode, and a solid polymer electrolyte to provide overcharge protection to the cell. The organic redox additives or shuttles are characterized by a high diffusion coefficient of at least 2.1.times.10.sup.-8 cm.sup.2 /second and a high onset potential of 2.5 volts or higher. Examples of such organic redox shuttle additives include an alkali metal salt of 1,2,4-triazole, an alkali metal salt of imidazole, 2,3,5,6-tetramethylpyrazine, 1,3,5-tricyanobenzene, and a dialkali metal salt of 3-4-dihydroxy-3-cyclobutene-1,2-dione.

  2. Capacity Decay Mechanism of Microporous Separator?Based All?Vanadium Redox Flow Batteries and its Recovery

    SciTech Connect (OSTI)

    Li, Bin; Luo, Qingtao; Wei, Xiaoliang; Nie, Zimin; Thomsen, Edwin C.; Chen, Baowei; Sprenkle, Vincent L.; Wang, Wei

    2014-02-01T23:59:59.000Z

    For all vanadium redox flow batteries (VRBs) with porous separators as membranes, convection effect is found to play a dominant role in the capacity decay of the cells over cycling by investigating the relationship between electrical performances and electrolyte compositions at both positive and negative sides. Although the concentration of total vanadium ions hardly changes at both sides over cycling, the net transfer of solutions from one side to another and thus asymmetrical valance of vanadium ions at both sides lead to the capacity fading and lower energy efficiency, which is confirmed to result from the hydraulic pressure differential at both sides of separators. In this paper, the hydraulic pressures of solutions at both sides can be in-situ monitored, and regulated by varying the gas pressures in electrolyte tanks. It is found that the capacity can be stabilized and the net transfer of solutions can be prevented by slightly tailoring the hydraulic pressure differential at both sides of separators, which, however, doesn’t work for Nafion membranes, suggesting the negligible convection factor in flow cells using Nafion membranes. Therefore, the possibility of porous separators allows long-term running for VRBs without capacity loss, highlighting a new pathway to develop membranes used in VRBs.

  3. Scientists capture 'redox moments' in living cells | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    moments' in living cells Better understanding of hardy bacteria enhances tool for biofuel creation Scientists have charted a significant signaling network in a tiny organism...

  4. TEMPO-based Catholyte for High Energy Density Nonaqueous Redox...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    TEMPO-based Catholyte for High Energy Density Nonaqueous Redox Flow Batteries. TEMPO-based Catholyte for High Energy Density Nonaqueous Redox Flow Batteries. Abstract: We will...

  5. Ni(III)/(IV) Bis(dicarbollide) as a Fast, Noncorrosive Redox Shuttle for Dye-Sensitized Solar Cells

    E-Print Network [OSTI]

    Ni(III)/(IV) Bis(dicarbollide) as a Fast, Noncorrosive Redox Shuttle for Dye-Sensitized Solar Cells-marks@northwestern.edu; chadnano@northwestern.edu The favorable energetics of dye-sensitized solar cell (DSC) constituents have. Marks,*,, and Joseph T. Hupp*,,,§ Department of Chemistry, Argonne-Northwestern Solar Energy Research

  6. Imposed currents in galvanic cells

    E-Print Network [OSTI]

    Biesheuvel, P. M.

    We analyze the steady-state behavior of a general mathematical model for reversible galvanic cells, such as redox flow cells, reversible solid oxide fuel cells, and rechargeable batteries. We consider not only operation ...

  7. Fuel cell system with coolant flow reversal

    DOE Patents [OSTI]

    Kothmann, Richard E. (Pittsburgh, PA)

    1986-01-01T23:59:59.000Z

    Method and apparatus for cooling electrochemical fuel cell system components. Periodic reversal of the direction of flow of cooling fluid through a fuel cell stack provides greater uniformity and cell operational temperatures. Flow direction through a recirculating coolant fluid circuit is reversed through a two position valve, without requiring modulation of the pumping component.

  8. Fuel cell with internal flow control

    DOE Patents [OSTI]

    Haltiner, Jr., Karl J. (Fairport, NY); Venkiteswaran, Arun (Karnataka, IN)

    2012-06-12T23:59:59.000Z

    A fuel cell stack is provided with a plurality of fuel cell cassettes where each fuel cell cassette has a fuel cell with an anode and cathode. The fuel cell stack includes an anode supply chimney for supplying fuel to the anode of each fuel cell cassette, an anode return chimney for removing anode exhaust from the anode of each fuel cell cassette, a cathode supply chimney for supplying oxidant to the cathode of each fuel cell cassette, and a cathode return chimney for removing cathode exhaust from the cathode of each fuel cell cassette. A first fuel cell cassette includes a flow control member disposed between the anode supply chimney and the anode return chimney or between the cathode supply chimney and the cathode return chimney such that the flow control member provides a flow restriction different from at least one other fuel cell cassettes.

  9. Mirrored serpentine flow channels for fuel cell

    DOE Patents [OSTI]

    Rock, Jeffrey Allan (Rochester, NY)

    2000-08-08T23:59:59.000Z

    A PEM fuel cell having serpentine flow field channels wherein the input/inlet legs of each channel border the input/inlet legs of the next adjacent channels in the same flow field, and the output/exit legs of each channel border the output/exit legs of the next adjacent channels in the same flow field. The serpentine fuel flow channels may be longer, and may contain more medial legs, than the serpentine oxidant flow channels.

  10. Nox2 redox signaling maintains essential cell populations in the Bryan C Dickinson1, Joseph Peltier2, Daniel Stone2, David V Schaffer2, and Christopher J

    E-Print Network [OSTI]

    Schaffer, David V.

    Nox2 redox signaling maintains essential cell populations in the brain Bryan C Dickinson1, Joseph Peltier2, Daniel Stone2, David V Schaffer2, and Christopher J Chang1,3 1Department of Chemistry indicator for hydrogen peroxide (H2O2), we show that adult hippocampal stem/progenitor cells (AHPs) generate

  11. Doped Yttrium Chromite-Ceria Composite as a Redox-Stable and Sulfur-Tolerant Anode for Solid Oxide Fuel Cells

    SciTech Connect (OSTI)

    Yoon, Kyung J.; Coyle, Christopher A.; Marina, Olga A.

    2011-12-11T23:59:59.000Z

    A Ca- and Co-doped yttrium chromite (YCCC) - samaria-doped ceria (SDC) composite was studied in relation to a potential use as a solid oxide fuel cell (SOFC) anode material. Tests performed using the yttria-stabilized zirconia (YSZ) electrolyte-supported cells revealed that the electrocatalytic activity of the YCCC-SDC anode towards hydrogen oxidation at 800 C was comparable to that of the Ni-YSZ anode. In addition, the YCCC-SDC anode exhibited superior sulfur tolerant characteristics showing less than 10% increase in a polarization resistance, fully reversible, upon exposure to 20 ppm H2S at 800 C. No performance degradation was observed during multiple reduction-oxidation (redox) cycles when the anode was intentionally exposed to the air environment followed by the reduction in hydrogen. The redox tolerance of the YCCC-SDC anode was attributed to the dimensional and chemical stability of the YCCC exhibiting minimal isothermal chemical expansion upon redox cycling.

  12. Transitioning from Fuel Cells to Redox Flow Cells | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn'tOriginEducationVideoStrategic|IndustrialCenter Gets People Work,Amy7AUnderstanding |

  13. Progress in Grid Scale Flow Batteries

    E-Print Network [OSTI]

    2011Year #12;Flow Battery Research at PNNL and Sandia #12 with industries and universities New Generation Redox Flow Batteries, PNNL Developed new generation redox flow

  14. Effects of interstitial flow on tumor cell migration

    E-Print Network [OSTI]

    Polacheck, William J. (William Joseph)

    2010-01-01T23:59:59.000Z

    Interstitial flow is the convective transport of fluid through tissue extracellular matrix. This creeping fluid flow has been shown to affect the morphology and migration of cells such as fibroblasts, cancer cells, endothelial ...

  15. REVIEW ARTICLE Redox regulation of intercellular transport

    E-Print Network [OSTI]

    Jackson, David

    REVIEW ARTICLE Redox regulation of intercellular transport Yoselin Benitez-Alfonso & David Jackson research has suggested the participa- tion of ROS in the regulation of PD transport. The study of several in cell redox homeostasis and PD transport, and the histological detection of hydrogen peroxide

  16. Co-flow planar SOFC fuel cell stack

    DOE Patents [OSTI]

    Chung, Brandon W.; Pham, Ai Quoc; Glass, Robert S.

    2004-11-30T23:59:59.000Z

    A co-flow planar solid oxide fuel cell stack with an integral, internal manifold and a casing/holder to separately seal the cell. This construction improves sealing and gas flow, and provides for easy manifolding of cell stacks. In addition, the stack construction has the potential for an improved durability and operation with an additional increase in cell efficiency. The co-flow arrangement can be effectively utilized in other electrochemical systems requiring gas-proof separation of gases.

  17. Determination of redox reaction rates and –orders by in-situ liquid cell electron microscopy of Pd and Au solution growth

    SciTech Connect (OSTI)

    Sutter, Eli A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Sutter, Peter W. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2014-12-03T23:59:59.000Z

    In-situ liquid cell transmission and scanning transmission electron microscopy (TEM/STEM) experiments are important as they provide direct insight into processes in liquids, such as solution growth of nanoparticles among others. In liquid cell TEM/STEM redox reaction experiments the hydrated electrons e?aq created by the electron beam are responsible for the reduction of metal-ion complexes. Here we investigate the rate equation of redox reactions involving reduction by e?aq generated by the electron beam during in-situ liquid TEM/STEM. Specifically we consider the growth of Pd on Au seeds in aqueous solutions containing Pd-chloro complexes. From the quantification of the rate of Pd deposition at different electron beam currents and as a function of distance from a stationary, nanometer-sized exciting beam, we determine that the reaction is first order with respect to the concentration of hydrated electrons, [e?aq]. By comparing Pd- and Au-deposition, we further demonstrate that measurements of the local deposition rate on nanoparticles in the solution via real-time imaging can be used to measure not only [e?aq] but also the rate of reduction of a metal-ion complex to zero-valent metal atoms in solution.

  18. Determination of redox reaction rates and –orders by in-situ liquid cell electron microscopy of Pd and Au solution growth

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Sutter, Eli A.; Sutter, Peter W.

    2014-12-03T23:59:59.000Z

    In-situ liquid cell transmission and scanning transmission electron microscopy (TEM/STEM) experiments are important as they provide direct insight into processes in liquids, such as solution growth of nanoparticles among others. In liquid cell TEM/STEM redox reaction experiments the hydrated electrons e?aq created by the electron beam are responsible for the reduction of metal-ion complexes. Here we investigate the rate equation of redox reactions involving reduction by e?aq generated by the electron beam during in-situ liquid TEM/STEM. Specifically we consider the growth of Pd on Au seeds in aqueous solutions containing Pd-chloro complexes. From the quantification of the rate of Pdmore »deposition at different electron beam currents and as a function of distance from a stationary, nanometer-sized exciting beam, we determine that the reaction is first order with respect to the concentration of hydrated electrons, [e?aq]. By comparing Pd- and Au-deposition, we further demonstrate that measurements of the local deposition rate on nanoparticles in the solution via real-time imaging can be used to measure not only [e?aq] but also the rate of reduction of a metal-ion complex to zero-valent metal atoms in solution.« less

  19. Determination of redox reaction rates and –orders by in-situ liquid cell electron microscopy of Pd and Au solution growth

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Sutter, Eli A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Sutter, Peter W. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2014-12-03T23:59:59.000Z

    In-situ liquid cell transmission and scanning transmission electron microscopy (TEM/STEM) experiments are important as they provide direct insight into processes in liquids, such as solution growth of nanoparticles among others. In liquid cell TEM/STEM redox reaction experiments the hydrated electrons e?aq created by the electron beam are responsible for the reduction of metal-ion complexes. Here we investigate the rate equation of redox reactions involving reduction by e?aq generated by the electron beam during in-situ liquid TEM/STEM. Specifically we consider the growth of Pd on Au seeds in aqueous solutions containing Pd-chloro complexes. From the quantification of the rate of Pd deposition at different electron beam currents and as a function of distance from a stationary, nanometer-sized exciting beam, we determine that the reaction is first order with respect to the concentration of hydrated electrons, [e?aq]. By comparing Pd- and Au-deposition, we further demonstrate that measurements of the local deposition rate on nanoparticles in the solution via real-time imaging can be used to measure not only [e?aq] but also the rate of reduction of a metal-ion complex to zero-valent metal atoms in solution.

  20. Microfabricated Renewable Beads-Trapping/Releasing Flow Cell...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Microfabricated Renewable Beads-TrappingReleasing Flow Cell for Rapid Antigen-Antibody Reaction in Chemiluminescent Immunoassay Microfabricated Renewable Beads-TrappingReleasing...

  1. Breakthrough Flow Battery Cell Stack: Transformative Electrochemical Flow Storage System (TEFSS)

    SciTech Connect (OSTI)

    None

    2010-09-09T23:59:59.000Z

    GRIDS Project: UTRC is developing a flow battery with a unique design that provides significantly more power than today's flow battery systems. A flow battery is a cross between a traditional battery and a fuel cell. Flow batteries store their energy in external tanks instead of inside the cell itself. Flow batteries have traditionally been expensive because the battery cell stack, where the chemical reaction takes place, is costly. In this project, UTRC is developing a new stack design that achieves 10 times higher power than today’s flow batteries. This high power output means the size of the cell stack can be smaller, reducing the amount of expensive materials that are needed. UTRC’s flow battery will reduce the cost of storing electricity for the electric grid, making widespread use feasible.

  2. Redox Flow Batteries, a Review

    E-Print Network [OSTI]

    Weber, Adam Z.

    2013-01-01T23:59:59.000Z

    P. C. Butler, "Advanced Batteries for Electric Vehicles andIntroduction," in Hnadbook of Batteries, 3rd Edition, D.T. B. Reddy, Handbook of Batteries, 2002). [67] R. Zito, US

  3. Redox Flow Batteries, a Review

    E-Print Network [OSTI]

    Weber, Adam Z.

    2013-01-01T23:59:59.000Z

    or novel hydrogen-storage materials are is needed. Althoughof storage tank volume, and thus hydrogen compression

  4. Redox Flow Batteries, a Review

    E-Print Network [OSTI]

    Weber, Adam Z.

    2013-01-01T23:59:59.000Z

    battery configuration. Lead-acid batteries do not shuttleincluding lead-acid, nickel-based, and lithium-ion batteries

  5. Redox Flow Batteries, a Review

    E-Print Network [OSTI]

    Weber, Adam Z.

    2013-01-01T23:59:59.000Z

    DC, 2008). "Energy Storage Technology Valuation Primer:storage technologies and does not require specific geographical siting, as pumped hydroelectric and compressed-air energyenergy. There are some technologies that enable practical storage

  6. Single chamber fuel cells: Flow geometry, rate and composition considerations

    SciTech Connect (OSTI)

    Stefan, Ionel C.; Jacobson, Craig P.; Visco, Steven J.; De Jonghe, Lutgard C.

    2003-11-17T23:59:59.000Z

    Four different single chamber fuel cell designs were compared using propane-air gas mixtures. Gas flow around the electrodes has a significant influence on the open circuit voltage and the power density of the cell. The strong influence of flow geometry is likely due to its effect on gas composition, particularly on the oxygen chemical potential at the two electrodes as a result of gas mixing. The chamber design which exposes the cathode first to the inlet gas was found to yield the best performance at lower flow rates, while the open tube design with the electrodes equally exposed to the inlet gas worked best at higher flow rates.

  7. Fuel Cell Assembly Process Flow for High Productivity

    E-Print Network [OSTI]

    Edwards, David A.

    Fuel Cell Assembly Process Flow for High Productivity Problem Presenter Ram Ramanan Bloom Energy: Introduction Bloom Energy manufactures power modules based on fuel cell technology. These are built up their possible placement within a cell assembly. Currently, these rules for assembling the basic components

  8. Renaissance in Flow-Cell Technologies: Recent Advancements and...

    Office of Environmental Management (EM)

    Presentation by Mike Perry, United Technologies Research Center, at the Flow Cells for Energy Storage Workshop held March 7-8, 2012, in Washington, DC. flowcells2012perry.pdf...

  9. Fuel cell with metal screen flow-field

    DOE Patents [OSTI]

    Wilson, M.S.; Zawodzinski, C.

    1998-08-25T23:59:59.000Z

    A polymer electrolyte membrane (PEM) fuel cell is provided with electrodes supplied with a reactant on each side of a catalyzed membrane assembly (CMA). The fuel cell includes a metal mesh defining a rectangular flow-field pattern having an inlet at a first corner and an outlet at a second corner located on a diagonal from the first corner, wherein all flow paths from the inlet to the outlet through the square flow field pattern are equivalent to uniformly distribute the reactant over the CMA. In a preferred form of metal mesh, a square weave screen forms the flow-field pattern. In a particular characterization of the present invention, a bipolar plate electrically connects adjacent fuel cells, where the bipolar plate includes a thin metal foil having an anode side and a cathode side; a first metal mesh on the anode side of the thin metal foil; and a second metal mesh on the cathode side of the thin metal foil. In another characterization of the present invention, a cooling plate assembly cools adjacent fuel cells, where the cooling plate assembly includes an anode electrode and a cathode electrode formed of thin conducting foils; and a metal mesh flow field there between for distributing cooling water flow over the electrodes to remove heat generated by the fuel cells. 11 figs.

  10. Fuel cell with metal screen flow-field

    DOE Patents [OSTI]

    Wilson, Mahlon S. (Los Alamos, NM); Zawodzinski, Christine (Los Alamos, NM)

    2001-01-01T23:59:59.000Z

    A polymer electrolyte membrane (PEM) fuel cell is provided with electrodes supplied with a reactant on each side of a catalyzed membrane assembly (CMA). The fuel cell includes a metal mesh defining a rectangular flow-field pattern having an inlet at a first corner and an outlet at a second corner located on a diagonal from the first corner, wherein all flow paths from the inlet to the outlet through the square flow field pattern are equivalent to uniformly distribute the reactant over the CMA. In a preferred form of metal mesh, a square weave screen forms the flow-field pattern. In a particular characterization of the present invention, a bipolar plate electrically connects adjacent fuel cells, where the bipolar plate includes a thin metal foil having an anode side and a cathode side; a first metal mesh on the anode side of the thin metal foil; and a second metal mesh on the cathode side of the thin metal foil. In another characterization of the present invention, a cooling plate assembly cools adjacent fuel cells, where the cooling plate assembly includes an anode electrode and a cathode electrode formed of thin conducting foils; and a metal mesh flow field therebetween for distributing cooling water flow over the electrodes to remove heat generated by the fuel cells.

  11. Combustor air flow control method for fuel cell apparatus

    DOE Patents [OSTI]

    Clingerman, Bruce J. (Palmyra, NY); Mowery, Kenneth D. (Noblesville, IN); Ripley, Eugene V. (Russiaville, IN)

    2001-01-01T23:59:59.000Z

    A method for controlling the heat output of a combustor in a fuel cell apparatus to a fuel processor where the combustor has dual air inlet streams including atmospheric air and fuel cell cathode effluent containing oxygen depleted air. In all operating modes, an enthalpy balance is provided by regulating the quantity of the air flow stream to the combustor to support fuel cell processor heat requirements. A control provides a quick fast forward change in an air valve orifice cross section in response to a calculated predetermined air flow, the molar constituents of the air stream to the combustor, the pressure drop across the air valve, and a look up table of the orifice cross sectional area and valve steps. A feedback loop fine tunes any error between the measured air flow to the combustor and the predetermined air flow.

  12. Fluid flow plate for decreased density of fuel cell assembly

    DOE Patents [OSTI]

    Vitale, Nicholas G. (Albany, NY)

    1999-01-01T23:59:59.000Z

    A fluid flow plate includes first and second outward faces. Each of the outward faces has a flow channel thereon for carrying respective fluid. At least one of the fluids serves as reactant fluid for a fuel cell of a fuel cell assembly. One or more pockets are formed between the first and second outward faces for decreasing density of the fluid flow plate. A given flow channel can include one or more end sections and an intermediate section. An interposed member can be positioned between the outward faces at an interface between an intermediate section, of one of the outward faces, and an end section, of that outward face. The interposed member can serve to isolate the reactant fluid from the opposing outward face. The intermediate section(s) of flow channel(s) on an outward face are preferably formed as a folded expanse.

  13. Liquid chromatography/Fourier transform IR spectrometry interface flow cell

    DOE Patents [OSTI]

    Johnson, Charles C. (Fairfield, OH); Taylor, Larry T. (Blacksburg, VA)

    1986-01-01T23:59:59.000Z

    A zero dead volume (ZDV) microbore high performance liquid chromatography (.mu.HPLC)/Fourier transform infrared (FTIR) interface flow cell includes an IR transparent crystal having a small diameter bore therein through which a sample liquid is passed. The interface flow cell further includes a metal holder in combination with a pair of inner, compressible seals for directly coupling the thus configured spectrometric flow cell to the outlet of a .mu.HPLC column end fitting to minimize the transfer volume of the effluents exiting the .mu.HPLC column which exhibit excellent flow characteristics due to the essentially unencumbered, open-flow design. The IR beam passes transverse to the sample flow through the circular bore within the IR transparent crystal, which is preferably comprised of potassium bromide (KBr) or calcium fluoride (CaF.sub.2), so as to minimize interference patterns and vignetting encountered in conventional parallel-plate IR cells. The long IR beam pathlength and lensing effect of the circular cross-section of the sample volume in combination with the refractive index differences between the solvent and the transparent crystal serve to focus the IR beam in enhancing sample detection sensitivity by an order of magnitude.

  14. Liquid chromatography/Fourier transform IR spectrometry interface flow cell

    DOE Patents [OSTI]

    Johnson, C.C.; Taylor, L.T.

    1985-01-04T23:59:59.000Z

    A zero dead volume (ZDV) microbore high performance liquid chromatography (..mu.. HPLC)/Fourier transform infrared (FTIR) interface flow cell includes an IR transparent crystal having a small diameter bore therein through which a sample liquid is passed. The interface flow cell further includes a metal holder in combination with a pair of inner, compressible seals for directly coupling the thus configured spectrometric flow cell to the outlet of a ..mu.. HPLC column end fitting to minimize the transfer volume of the effluents exiting the ..mu.. HPLC column which exhibit excellent flow characteristics due to the essentially unencumbered, open-flow design. The IR beam passes transverse to the sample flow through the circular bore within the IR transparent crystal, which is preferably comprised of potassium bromide (KBr) or calcium fluoride (CaF/sub 2/), so as to minimize interference patterns and vignetting encountered in conventional parallel-plate IR cells. The long IR beam pathlength and lensing effect of the circular cross-section of the sample volume in combination with the refractive index differences between the solvent and the transparent crystal serve to focus the IR beam in enhancing sample detection sensitivity by an order of magnitude.

  15. Global helioseismic evidence for a deeply penetrating Solar meridional flow consisting of multiple flow cells

    E-Print Network [OSTI]

    Schad, A; Roth, M

    2013-01-01T23:59:59.000Z

    We use a novel global helioseismic analysis method to infer the meridional flow in the deep Solar interior. The method is based on the perturbation of eigenfunctions of Solar p modes due to meridional flow. We apply this method to time series obtained from Dopplergrams measured by the Michelson Doppler Imager aboard the Solar and Heliospheric Observatory (SOHO) covering the observation period 2004-2010. Our results show evidence that the meridional flow reaches down to the base of the convection zone. The flow profile has a complex spatial structure consisting of multiple flow cells distributed in depth and latitude. Toward the Solar surface, our results are in good agreement with flow measurements from local helioseismology.

  16. Gradient isolator for flow field of fuel cell assembly

    DOE Patents [OSTI]

    Ernst, William D. (Troy, NY)

    1999-01-01T23:59:59.000Z

    Isolator(s) include isolating material and optionally gasketing material strategically positioned within a fuel cell assembly. The isolating material is disposed between a solid electrolyte and a metal flow field plate. Reactant fluid carried by flow field plate channel(s) forms a generally transverse electrochemical gradient. The isolator(s) serve to isolate electrochemically a portion of the flow field plate, for example, transversely outward from the channel(s), from the electrochemical gradient. Further, the isolator(s) serve to protect a portion of the solid electrolyte from metallic ions.

  17. Gradient isolator for flow field of fuel cell assembly

    DOE Patents [OSTI]

    Ernst, W.D.

    1999-06-15T23:59:59.000Z

    Isolator(s) include isolating material and optionally gasketing material strategically positioned within a fuel cell assembly. The isolating material is disposed between a solid electrolyte and a metal flow field plate. Reactant fluid carried by flow field plate channel(s) forms a generally transverse electrochemical gradient. The isolator(s) serve to isolate electrochemically a portion of the flow field plate, for example, transversely outward from the channel(s), from the electrochemical gradient. Further, the isolator(s) serve to protect a portion of the solid electrolyte from metallic ions. 4 figs.

  18. Long waves in parallel flow in Hele-Shaw cells

    SciTech Connect (OSTI)

    Zeybek, M.; Yortsos, Y.C.

    1991-04-01T23:59:59.000Z

    During the past several years the flow of immiscible flow in Hele-Shaw cells and porous media has been investigated extensively. Of particular interest to most studies has been frontal displacement, specifically viscous fingering instabilities and finger growth. The practical ramifications regarding oil recovery, as well as many other industrial processes in porous media, have served as the primary driving force for most of these investigations. By contrast, little attention has been paid to the motion of lateral fluid interface, which are parallel to the main flow direction. Parallel flow is an often encountered, although much overlooked regime. The evolution of fluid interfaces in parallel flow in Hele-Shaw cells is studied both theoretically and experimentally in the large capillary number limit. It is shown that such interfaces support wave motion, the amplitude of which for long waves is governed by the KdV equation. Experiments are conducted in a long Hele-Shaw cell that validate the theory in the symmetric case. 35 refs., 16 figs.

  19. A flow field enabling operating direct methanol fuel cells with highly concentrated methanol

    E-Print Network [OSTI]

    Zhao, Tianshou

    A flow field enabling operating direct methanol fuel cells with highly concentrated methanol Q. Xu Available online 8 October 2010 Keywords: Fuel cells Direct methanol fuel cells Concentrated methanol Flow field a b s t r a c t In this work, an anode flow field that allows a direct methanol fuel cell (DMFC

  20. Cross-flow electrochemical reactor cells, cross-flow reactors, and use of cross-flow reactors for oxidation reactions

    DOE Patents [OSTI]

    Balachandran, Uthamalingam (Hinsdale, IL); Poeppel, Roger B. (Glen Ellyn, IL); Kleefisch, Mark S. (Naperville, IL); Kobylinski, Thaddeus P. (Lisle, IL); Udovich, Carl A. (Joliet, IL)

    1994-01-01T23:59:59.000Z

    This invention discloses cross-flow electrochemical reactor cells containing oxygen permeable materials which have both electron conductivity and oxygen ion conductivity, cross-flow reactors, and electrochemical processes using cross-flow reactor cells having oxygen permeable monolithic cores to control and facilitate transport of oxygen from an oxygen-containing gas stream to oxidation reactions of organic compounds in another gas stream. These cross-flow electrochemical reactors comprise a hollow ceramic blade positioned across a gas stream flow or a stack of crossed hollow ceramic blades containing a channel or channels for flow of gas streams. Each channel has at least one channel wall disposed between a channel and a portion of an outer surface of the ceramic blade, or a common wall with adjacent blades in a stack comprising a gas-impervious mixed metal oxide material of a perovskite structure having electron conductivity and oxygen ion conductivity. The invention includes reactors comprising first and second zones seprated by gas-impervious mixed metal oxide material material having electron conductivity and oxygen ion conductivity. Prefered gas-impervious materials comprise at least one mixed metal oxide having a perovskite structure or perovskite-like structure. The invention includes, also, oxidation processes controlled by using these electrochemical reactors, and these reactions do not require an external source of electrical potential or any external electric circuit for oxidation to proceed.

  1. Fuel cell with interdigitated porous flow-field

    DOE Patents [OSTI]

    Wilson, M.S.

    1997-06-24T23:59:59.000Z

    A polymer electrolyte membrane (PEM) fuel cell is formed with an improved system for distributing gaseous reactants to the membrane surface. A PEM fuel cell has an ionic transport membrane with opposed catalytic surfaces formed thereon and separates gaseous reactants that undergo reactions at the catalytic surfaces of the membrane. The fuel cell may also include a thin gas diffusion layer having first and second sides with a first side contacting at least one of the catalytic surfaces. A macroporous flow-field with interdigitated inlet and outlet reactant channels contacts the second side of the thin gas diffusion layer for distributing one of the gaseous reactants over the thin gas diffusion layer for transport to an adjacent one of the catalytic surfaces of the membrane. The porous flow field may be formed from a hydrophilic material and provides uniform support across the backside of the electrode assembly to facilitate the use of thin backing layers. 9 figs.

  2. Fuel Cell Technologies Overview: 2012 Flow Cells for Energy Storage

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't YourTransport inEnergy0.pdfTechnologies Program (FCTP)Overview Fuel CellFuel CellWorkshop |

  3. Investigation of redox processes at semiconductor electrode liquid junctions

    SciTech Connect (OSTI)

    Koval, C.A.

    1990-08-01T23:59:59.000Z

    Research in fundamental aspects of photoelectrochemical cells has been in the following areas: chemical probes for hot carrier processes, electrostatic theory for describing electrical interactions at interfaces, and kinetics of electron transfer at ideal semiconductor solution interfaces. Our goal is to achieve a better understanding of dark and photo-induced current flow at the semiconductor electrode/redox electrolyte interface (SEI) so that devices and processes utilizing this interface for solar energy conversion can be developed or improved. Our most important accomplishment has been the development of a redox system capable of detecting hot electrons at the p-InP/acetonitrile interface. Also, we have examined electrostatic theory for the image potential of an ion as a function of distance from the SEI. Finally, our group was one of the first to realize that the 2-dimensional metal chalcogenides (MC) are excellent materials for fundamental studies of electron transfer at the SEI. One of the chief potential advantages for use of MC's is the formation of semiconductor/liquid junctions with nearly ideal electrochemical properties. 27 refs., 1 fig.

  4. Impact of membrane characteristics on the performance and cycling of the Br2-H2 redox flow cell

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC) EnvironmentalGyroSolé(tm)Hydrogen StorageITERITERBuildingNanoscale

  5. Liquid Water Dynamics in a Model Polymer Electrolyte Fuel Cell Flow Channel

    E-Print Network [OSTI]

    Victoria, University of

    Liquid Water Dynamics in a Model Polymer Electrolyte Fuel Cell Flow Channel by Chris Miller in a Model Polymer Electrolyte Fuel Cell Flow Channel by Chris Miller Bachelors of Engineering, University in a polymer electrolyte fuel cell is a critical issue in ensuring high cell performance. The water production

  6. Improved Flow-Field Structures for Direct Methanol Fuel Cells

    SciTech Connect (OSTI)

    Gurau, Bogdan

    2013-05-31T23:59:59.000Z

    The direct methanol fuel cell (DMFC) is ideal if high energy-density liquid fuels are required. Liquid fuels have advantages over compressed hydrogen including higher energy density and ease of handling. Although state-of-the-art DMFCs exhibit manageable degradation rates, excessive fuel crossover diminishes system energy and power density. Although use of dilute methanol mitigates crossover, the concomitant lowering of the gross fuel energy density (GFED) demands a complex balance-of-plant (BOP) that includes higher flow rates, external exhaust recirculation, etc. An alternative approach is redesign of the fuel delivery system to accommodate concentrated methanol. NuVant Systems Inc. (NuVant) will maximize the GFED by design and assembly of a DMFC that uses near neat methanol. The approach is to tune the diffusion of highly concentrated methanol (to the anode catalytic layer) to the back-diffusion of water formed at the cathode (i.e. in situ generation of dilute methanol at the anode layer). Crossover will be minimized without compromising the GFED by innovative integration of the anode flow-field and the diffusion layer. The integrated flow-field-diffusion-layers (IFDLs) will widen the current and potential DMFC operating ranges and enable the use of cathodes optimized for hydrogen-air fuel cells.

  7. Flow Cells for Energy Storage Workshop | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page onYouTube YouTube Note: Since the.pdf Flash2006-52.pdf0.pdf Flash2008-50.pdf4.pdf0 Flash2011-40EnergyStrikeFlow Cells

  8. Effects of flow cell design on charge percolation and storage...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Electrochemical flow capacitor Energy storage Flow battery Flowable electrode Supercapacitor a b s t r a c t The electrochemical flow capacitor (EFC) is an electrical energy...

  9. Upgrading the Vanadium Redox Battery | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Upgrading the Vanadium Redox Battery Upgrading the Vanadium Redox Battery New electrolyte mix increases energy storage by 70 percent After developing a more effective...

  10. Cerebral blood flow in sickle cell cerebrovascular disease

    SciTech Connect (OSTI)

    Huttenlocher, P.R.; Moohr, J.W.; Johns, L.; Brown, F.D.

    1984-05-01T23:59:59.000Z

    Cerebral blood flow (CBF) has been studied by the xenon-133 (/sup 133/Xe) inhalation method in 16 children with suspected sickle cell cerebrovascular disease. Abnormalities consisting of decreases in total, hemispheral, or regional CBF were found in 17 of 26 studies. Eleven studies performed immediately after stroke, transient ischemic attack, or depression of state of alertness showed abnormalities. In addition to confirming regional cerebrovascular insufficiency in children with stroke due to major cerebral artery occlusion, the method detected diffuse decrease in CBF in children with stupor, coma, and seizures who had normal angiographic findings. In contrast, six of seven studies obtained after exchange transfusion or during maintenance on hypertransfusion therapy showed normal findings. The difference between results in patients with acute neurologic disturbances and those receiving transfusion therapy was statistically significant (P less than .005). The data indicate that the /sup 133/Xe method reliably demonstrates cerebrovascular impairment in sickle cell disease. They also suggest that CBF changes in patients with sickle cell disease can be reversed by exchange transfusion and by hypertransfusion therapy. The /sup 133/Xe CBF method may be useful for following up children with sickle cell disease who are at high risk for recurrent stroke.

  11. BIOENERGY AND BIOFUELS A multi-electrode continuous flow microbial fuel cell

    E-Print Network [OSTI]

    BIOENERGY AND BIOFUELS A multi-electrode continuous flow microbial fuel cell with separator microbial fuel cells (MFCs) requires the development of compact reactors with multiple electro- des continuous flow treatment using actual wastewaters. Keywords Microbial fuel cell . Scaling up . Separator

  12. Journal of Power Sources 128 (2004) 5460 Microfluidic fuel cell based on laminar flow

    E-Print Network [OSTI]

    Kenis, Paul J. A.

    2004-01-01T23:59:59.000Z

    Journal of Power Sources 128 (2004) 54­60 Microfluidic fuel cell based on laminar flow Eric R a novel microfluidic fuel cell concept that utilizes the occurrence of multi-stream laminar flow turbulent mixing. Preliminary results indicate that this novel fuel cell concept may lead to the development

  13. Electrochimica Acta 50 (2005) 53905398 Membraneless laminar flow-based micro fuel cells operating in alkaline,

    E-Print Network [OSTI]

    Kenis, Paul J. A.

    2005-01-01T23:59:59.000Z

    Electrochimica Acta 50 (2005) 5390­5398 Membraneless laminar flow-based micro fuel cells operating) in membraneless, laminar flow-based micro fuel cells (LF-FCs) eliminates several PEM-related issues such as fuel the anode is in acidic media while the cathode is in alkali, or vice versa. Operating a fuel cell under

  14. Experimental Study of Water Droplet Flows in a Model PEM Fuel Cell Gas Microchannel

    E-Print Network [OSTI]

    Victoria, University of

    Experimental Study of Water Droplet Flows in a Model PEM Fuel Cell Gas Microchannel by Grant Minor Experimental Study of Water Droplet Flows in a Model PEM Fuel Cell Gas Microchannel by Grant Minor B. Eng. Mgmt Committee Member, Mechanical Engineering). Abstract Liquid water formation and flooding in PEM fuel cell gas

  15. Dynamic Modes of Red Blood Cells in Oscillatory Shear Flow

    E-Print Network [OSTI]

    Hiroshi Noguchi

    2010-06-12T23:59:59.000Z

    The dynamics of red blood cells (RBCs) in oscillatory shear flow was studied using differential equations of three variables: a shape parameter, the inclination angle $\\theta$, and phase angle $\\phi$ of the membrane rotation. In steady shear flow, three types of dynamics occur depending on the shear rate and viscosity ratio. i) tank-treading (TT): $\\phi$ rotates while the shape and $\\theta$ oscillate. ii) tumbling (TB): $\\theta$ rotates while the shape and $\\phi$ oscillate. iii) intermediate motion: both $\\phi$ and $\\theta$ rotate synchronously or intermittently. In oscillatory shear flow, RBCs show various dynamics based on these three motions. For a low shear frequency with zero mean shear rate, a limit-cycle oscillation occurs, based on the TT or TB rotation at a high or low shear amplitude, respectively. This TT-based oscillation well explains recent experiments. In the middle shear amplitude, RBCs show an intermittent or synchronized oscillation. As shear frequency increases, the vesicle oscillation becomes delayed with respect to the shear oscillation. At a high frequency, multiple limit-cycle oscillations coexist. For a high mean shear rate with small shear oscillation, the shape and $\\theta$ oscillate in the TT motion but only one attractor exists even at high shear frequencies. The measurement of these oscillatory modes is a promising tool for quantifying the viscoelasticity of RBCs and synthetic capsules.

  16. Redox Shuttles DOI: 10.1002/anie.201002181

    E-Print Network [OSTI]

    (dicarbollide) Redox Shuttles in Dye-Sensitized Solar Cells** Alexander M. Spokoyny, Tina C. Li, Omar K. Farha, Charles* Dye-sensitized solar cells (DSCs) are potential next-gener- ation solar electricity sources since molecular dyes to increase light absorption,[3] evaluation of alternative semiconducting photoanodes

  17. Solid oxide fuel cell having compound cross flow gas patterns

    DOE Patents [OSTI]

    Fraioli, Anthony V. (Hawthorn Woods, IL)

    1985-01-01T23:59:59.000Z

    A core construction for a fuel cell is disclosed having both parallel and cross flow passageways for the fuel and the oxidant gases. Each core passageway is defined by electrolyte and interconnect walls. Each electrolyte wall consists of cathode and anode materials sandwiching an electrolyte material. Each interconnect wall is formed as a sheet of inert support material having therein spaced small plugs of interconnect material, where cathode and anode materials are formed as layers on opposite sides of each sheet and are electrically connected together by the interconnect material plugs. Each interconnect wall in a wavy shape is connected along spaced generally parallel line-like contact areas between corresponding spaced pairs of generally parallel electrolyte walls, operable to define one tier of generally parallel flow passageways for the fuel and oxidant gases. Alternate tiers are arranged to have the passageways disposed normal to one another. Solid mechanical connection of the interconnect walls of adjacent tiers to the opposite sides of the common electrolyte wall therebetween is only at spaced point-like contact areas, 90 where the previously mentioned line-like contact areas cross one another.

  18. Solid oxide fuel cell having compound cross flow gas patterns

    DOE Patents [OSTI]

    Fraioli, A.V.

    1983-10-12T23:59:59.000Z

    A core construction for a fuel cell is disclosed having both parallel and cross flow passageways for the fuel and the oxidant gases. Each core passageway is defined by electrolyte and interconnect walls. Each electrolyte wall consists of cathode and anode materials sandwiching an electrolyte material. Each interconnect wall is formed as a sheet of inert support material having therein spaced small plugs of interconnect material, where cathode and anode materials are formed as layers on opposite sides of each sheet and are electrically connected together by the interconnect material plugs. Each interconnect wall in a wavy shape is connected along spaced generally parallel line-like contact areas between corresponding spaced pairs of generally parallel electrolyte walls, operable to define one tier of generally parallel flow passageways for the fuel and oxidant gases. Alternate tiers are arranged to have the passageways disposed normal to one another. Solid mechanical connection of the interconnect walls of adjacent tiers to the opposite sides of the common electrolyte wall therebetween is only at spaced point-like contact areas, 90 where the previously mentioned line-like contact areas cross one another.

  19. Analysis of Pt/C electrode performance in a flowing-electrolyte alkaline fuel cell

    E-Print Network [OSTI]

    Kenis, Paul J. A.

    Analysis of Pt/C electrode performance in a flowing- electrolyte alkaline fuel cell Fikile R cell Electrode characterization X-ray micro-computed tomography Microfluidic fuel cell Carbonates a b a microfluidic H2/O2 fuel cell as an analytical platform. Both anodes and cathodes were investigated

  20. A spectral boundary integral method for flowing blood cells Hong Zhao a

    E-Print Network [OSTI]

    Olson, Luke

    A spectral boundary integral method for flowing blood cells Hong Zhao a , Amir H.G. Isfahani January 2010 Keywords: Stokes flow Particle-mesh Ewald Red blood cells Spherical harmonics Boundary element methods a b s t r a c t A spectral boundary integral method for simulating large numbers of blood

  1. Redox shuttles for lithium ion batteries

    DOE Patents [OSTI]

    Weng, Wei; Zhang, Zhengcheng; Amine, Khalil

    2014-11-04T23:59:59.000Z

    Compounds may have general Formula IVA or IVB. ##STR00001## where, R.sup.8, R.sup.9, R.sup.10, and R.sup.11 are each independently selected from H, F, Cl, Br, CN, NO.sub.2, alkyl, haloalkyl, and alkoxy groups; X and Y are each independently O, S, N, or P; and Z' is a linkage between X and Y. Such compounds may be used as redox shuttles in electrolytes for use in electrochemical cells, batteries and electronic devices.

  2. ORIGINAL PAPER Redox flow batteries: a review

    E-Print Network [OSTI]

    Mench, Matthew M.

    conducting phase O Oxidant R Reductant 1 Introduction Renewable-energy sources, such as solar and wind · Philip N. Ross · Jeffrey T. Gostick · Qinghua Liu Received: 12 July 2011 / Accepted: 16 August 2011 Ó batteries (RFBs) are enjoying a renaissance due to their ability to store large amounts of electrical energy

  3. Redox Flow Batteries - Energy Innovation Portal

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's PossibleRadiation Protection RadiationRecord-SettingHead of Contracting Activity (HCA)Storage

  4. Redox shuttle additives for overcharge protection in lithium batteries

    E-Print Network [OSTI]

    Richardson, Thomas J.; Ross Jr., P.N.

    1999-01-01T23:59:59.000Z

    No. 5,763,119. “Redox Shuttle Additives for Overchargeprotection, electrolytes, additives, redox shuttleREDOX SHUTTLE ADDITIVES FOR OVERCHARGE PROTECTION IN LITHIUM

  5. Computation of the Redox and Protonation Properties of Quinones...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Computation of the Redox and Protonation Properties of Quinones: Towards the Prediction of Redox Cycling Natural Products. Computation of the Redox and Protonation Properties of...

  6. Investigation of a U-Shaped Fuel Cell Flow Channel with Particle Image Velocimetry (PIV)

    E-Print Network [OSTI]

    Victoria, University of

    Investigation of a U-Shaped Fuel Cell Flow Channel with Particle Image Velocimetry (PIV phenomena that occur within serpentine reactant transport channels of fuel cells. Achieving effective mixing within these channels is crucial for the proper operation of the fuel cell and proper understanding

  7. Characterization of Limiting Factors in Laminar Flow-Based Membraneless Microfuel Cells

    E-Print Network [OSTI]

    Kenis, Paul J. A.

    are underway to develop and optimize microscale fuel cells as high-energy-density power source alternatives, where fuel and oxidant are oxidized and re- duced, respectively, is essential for fuel cell optimization reports the analysis of a microflu- idic fuel cell based on laminar flow using an external reference

  8. Holme et al. Soil Redox Sensor Networks RADIO FREQUENCY ENABLED SOIL REDOX POTENTIAL

    E-Print Network [OSTI]

    Rubinstein, Benjamin

    Holme et al. Soil Redox Sensor Networks RADIO FREQUENCY ENABLED SOIL REDOX POTENTIAL SENSOR technologies that may be combined into a cost effective soil redox sensor network, discuss the merits of each as a component of said network, describe a prototype soil redox sensor network and perform basic laboratory

  9. Investigating Cell Adhesion via Parallel Disk Rotational Flow: A Biocompatibility Study

    E-Print Network [OSTI]

    Rocha, Aracely

    2011-08-08T23:59:59.000Z

    INVESTIGATING CELL ADHESION VIA PARALLEL DISK ROTATIONAL FLOW: A BIOCOMPATIBILITY STUDY A Thesis by ARACELY ROCHA Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE December 2008 Major Subject: Mechanical Engineering INVESTIGATING CELL ADHESION VIA PARALLEL DISK ROTATIONAL FLOW: A BIOCOMPATIBILITY STUDY A Thesis by ARACELY ROCHA Submitted to the Office...

  10. Development of a cell-based stream flow routing model 

    E-Print Network [OSTI]

    Raina, Rajeev

    2005-08-29T23:59:59.000Z

    This study presents the development of a cell-based routing model. The model developed is a two parameter hydrological routing model that uses a coarse resolution stream network to route runoff from each cell in the watershed ...

  11. Nanomaterials for Fuel cells, Batteries, and Supercapacitors Flow Batteries

    E-Print Network [OSTI]

    Dutta, Indranath

    nanoparticles with high activity for formic acid oxidation." Journal of Power Sources 195(4):1103-1106. 7. Li, Z. 2010. "Noncovalently functionalized graphitic mesoporous carbon as a stable support of Pt nanoparticles.1016/j.elecom.2009.08.053 Fuel Cells: Direct Methanol and Formic Acid Fuel Cells 3. Song, P; Zhang, XY

  12. Microfluidic Electroporative Flow Cytometry for Studying Single-Cell Biomechanics

    E-Print Network [OSTI]

    Lu, Chang

    and metastasis. Screening of cells based on their biome- chanical properties provides rapid tools for label-10A, MCF-7, and 12-O-tetradecanoylphorbol-13-acetate-treated MCF-7) with different malignancy correlation exists between an increase in deformability and progression from a nontumorigenic cell line

  13. Development of a cell-based stream flow routing model

    E-Print Network [OSTI]

    Raina, Rajeev

    2005-08-29T23:59:59.000Z

    This study presents the development of a cell-based routing model. The model developed is a two parameter hydrological routing model that uses a coarse resolution stream network to route runoff from each cell in the watershed to the outlet...

  14. Investigation of Temperature-Driven Water Transport in Polymer Electrolyte Fuel Cell: Phase-Change-Induced Flow

    E-Print Network [OSTI]

    Mench, Matthew M.

    -Change-Induced Flow Soowhan Kim* and M. M. Mench**,z Fuel Cell Dynamics and Diagnostics Laboratory, DepartmentInvestigation of Temperature-Driven Water Transport in Polymer Electrolyte Fuel Cell: Phase electrolyte fuel cell materials subjected to a temperature gradient. Contrary to thermo-osmotic flow in fuel

  15. Characterization of protein redox dynamics induced during light-to-dark transitions and nutrient limitation in cyanobacteria

    SciTech Connect (OSTI)

    Ansong, Charles; Sadler, Natalie C.; Hill, Eric A.; Lewis, Michael P.; Zink, Erika M.; Smith, Richard D.; Beliaev, Alex S.; Konopka, Allan; Wright, Aaron T.

    2014-07-03T23:59:59.000Z

    Protein redox chemistry constitutes a major void in knowledge pertaining to photoautotrophic system regulation and signaling processes. We have employed a chemical biology approach to analyze redox sensitive proteins in live Synechococcus sp. PCC 7002 cells in both light and dark periods, and to understand how cellular redox balance is disrupted during nutrient perturbation. The present work identified several novel putative redox-sensitive proteins that are involved in the generation of reductant, macromolecule synthesis, and carbon flux through central metabolic pathways, and may be involved in cell signaling and response mechanisms. Furthermore, our research suggests that dynamic redox changes in response to specific nutrient limitations contribute to the regulatory changes driven by a shift from light to dark. Taken together, these results contribute to the high-level understanding of post-translational mechanisms regulating flux distributions and therefore present potential metabolic engineering targets for redirecting carbon towards biofuel precursors.

  16. Redox Shuttle Additives | Argonne National Laboratory

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    available for licensing: A series of novel redox shuttle additives for lithium-ion batteries Seven-technology suite helps reduce battery costs Provides overcharge...

  17. Flow cytometry aids basic cell biology research and drug discovery

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC) Environmental Assessments (EA)Budget(DANCE) Target 1 Flight Path°Floor Support84Flow

  18. Redox reactions of reduced flavin mononucleotide (FMN), riboflavin...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Redox reactions of reduced flavin mononucleotide (FMN), riboflavin (RBF), and anthraquinone-2,6-disulfonate (AQDS) with Redox reactions of reduced flavin mononucleotide (FMN),...

  19. Enrichment of Functional Redox Reactive Proteins and Identification...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Redox Reactive Proteins and Identification by Mass Spectrometry Results in Several Terminal Fe(III) Enrichment of Functional Redox Reactive Proteins and Identification by Mass...

  20. Novel Redox Shuttles for Overcharge Protection of Lithium-Ion...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Redox Shuttles for Overcharge Protection of Lithium-Ion Batteries Technology available for licensing: Electrolytes containing novel redox shuttles (electron transporters) for...

  1. Redox Chemistry in Thin Layers of Organometallic Complexes Prepared...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Redox Chemistry in Thin Layers of Organometallic Complexes Prepared Using Ion Soft Landing. Redox Chemistry in Thin Layers of Organometallic Complexes Prepared Using Ion Soft...

  2. A new flow field design for polymer electrolyte-based fuel cells C. Xu, T.S. Zhao *

    E-Print Network [OSTI]

    Zhao, Tianshou

    the concentration polarization. They also found that liquid water accumulated more rap- idly under channel ribs between adjacent flow channels over the entire electrode surface than does the conventional flow field cell; Water flooding; Flow field; Under-rib convection 1. Introduction Polymer electrolyte membrane

  3. Microfluidic System for Facilitated Quantification of Nanoparticle Accumulation to Cells Under Laminar Flow

    E-Print Network [OSTI]

    Simon, Scott I.

    Microfluidic System for Facilitated Quantification of Nanoparticle Accumulation to Cells Under to endothelial receptors has led to the rapid devel- opment of targeted nanoparticles for drug, gene and imaging nanoparticle accumulation under phys- iologically-relevant laminar flow. We designed reversibly vacuum

  4. Parallel flow in Hele-Shaw cells with ferrofluids Jos'e A. Miranda

    E-Print Network [OSTI]

    Widom, Michael

    -Helmholtz instability for inviscid fluids. For viscous fluids they deri* *ved a Kelvin- Helmholtz-Darcy equation] incorporated inertial terms into the equation of motion in a Hele-Shaw cell and* * found a Kelvin was governed by the Darcy's law flow of viscou* *s fluids. Their experimental results supported

  5. Parallel flow in HeleShaw cells with ferrofluids Jos'e A. Miranda

    E-Print Network [OSTI]

    Widom, Michael

    ­ Helmholtz­Darcy equation and found the threshold for instability was governed by inertial effects, while. Gondret and Rabaud [5] incorporated inertial terms into the equation of motion in a Hele­Shaw cell the wave velocity was governed by the Darcy's law flow of viscous fluids. Their experimental results

  6. Cartesian Cut Cell Two-Fluid Solver for Hydraulic Flow Problems

    E-Print Network [OSTI]

    Ingram, David

    Cartesian Cut Cell Two-Fluid Solver for Hydraulic Flow Problems L. Qian1 ; D. M. Causon2 ; D. M. Ingram3 ; and C. G. Mingham4 Abstract: A two-fluid solver which can be applied to a variety of hydraulic with a sloping beach is also calculated to demonstrate the applicability of the method to real hydraulic problems

  7. Highly conductive composites for fuel cell flow field plates and bipolar plates

    DOE Patents [OSTI]

    Jang, Bor Z; Zhamu, Aruna; Song, Lulu

    2014-10-21T23:59:59.000Z

    This invention provides a fuel cell flow field plate or bipolar plate having flow channels on faces of the plate, comprising an electrically conductive polymer composite. The composite is composed of (A) at least 50% by weight of a conductive filler, comprising at least 5% by weight reinforcement fibers, expanded graphite platelets, graphitic nano-fibers, and/or carbon nano-tubes; (B) polymer matrix material at 1 to 49.9% by weight; and (C) a polymer binder at 0.1 to 10% by weight; wherein the sum of the conductive filler weight %, polymer matrix weight % and polymer binder weight % equals 100% and the bulk electrical conductivity of the flow field or bipolar plate is at least 100 S/cm. The invention also provides a continuous process for cost-effective mass production of the conductive composite-based flow field or bipolar plate.

  8. Redox polymer electrodes for advanced batteries

    DOE Patents [OSTI]

    Gregg, B.A.; Taylor, A.M.

    1998-11-24T23:59:59.000Z

    Advanced batteries having a long cycle lifetime are provided. More specifically, the present invention relates to electrodes made from redox polymer films and batteries in which either the positive electrode, the negative electrode, or both, comprise redox polymers. Suitable redox polymers for this purpose include pyridyl or polypyridyl complexes of transition metals like iron, ruthenium, osmium, chromium, tungsten and nickel; porphyrins (either free base or metallo derivatives); phthalocyanines (either free base or metallo derivatives); metal complexes of cyclams, such as tetraazacyclotetradecane; metal complexes of crown ethers and metallocenes such as ferrocene, cobaltocene and ruthenocene. 2 figs.

  9. Redox polymer electrodes for advanced batteries

    DOE Patents [OSTI]

    Gregg, Brian A. (Golden, CO); Taylor, A. Michael (Golden, CO)

    1998-01-01T23:59:59.000Z

    Advanced batteries having a long cycle lifetime are provided. More specifically, the present invention relates to electrodes made from redox polymer films and batteries in which either the positive electrode, the negative electrode, or both, comprise redox polymers. Suitable redox polymers for this purpose include pyridyl or polypyridyl complexes of transition metals like iron, ruthenium, osmium, chromium, tungsten and nickel; porphyrins (either free base or metallo derivatives); phthalocyanines (either free base or metallo derivatives); metal complexes of cyclams, such as tetraazacyclotetradecane; metal complexes of crown ethers and metallocenes such as ferrocene, cobaltocene and ruthenocene.

  10. Pollution of Natural Waters 1. Redox chemistry

    E-Print Network [OSTI]

    Schofield, Jeremy

    . Eutrophication 4. Water treatment 1. Redox chemistry #15; Principle of equilibration of chemical system R Keq;sh and other aquatic life { Shift to anaerobic metabolic mechanisms #15; Eutrophication: agin

  11. Constructal flow structure for a PEM fuel cell J.V.C. Vargas a,*, J.C. Ordonez b

    E-Print Network [OSTI]

    Ordonez, Juan C.

    such as in a fuel cell, leading to high cost and computational time even for the simulation of a few selected casesConstructal flow structure for a PEM fuel cell J.V.C. Vargas a,*, J.C. Ordonez b , A. Bejan c the internal structure (relative sizes, spacings) and external shape (aspect ratios) of a unit PEM fuel cell so

  12. Electrochemical study of multi-electrode microbial fuel cells under fed-batch and continuous flow conditions

    E-Print Network [OSTI]

    Electrochemical study of multi-electrode microbial fuel cells under fed-batch and continuous flow November 2013 Available online 18 December 2013 Keywords: Multi-electrode Microbial fuel cells Hydraulic connected microbial fuel cells (MFCs) was compared with the reactors operated using individual electrical

  13. A microfluidic flow-cell for the study of the ultrafast dynamics of biological systems

    SciTech Connect (OSTI)

    Chauvet, Adrien, E-mail: adrien.chauvet@epfl.ch; Chergui, Majed [Ecole Polytechnique Fédérale de Lausanne (EPFL), Laboratoire de Spectroscopie Ultrarapide, ISIC, Faculté des Sciences de Base, Station 6, 1015 Lausanne (Switzerland); Tibiletti, Tania; Caffarri, Stefano [Aix Marseille Université, CNRS, CEA, UMR 7265 Biologie Végétale et Microbiologie Environnementales, 13009 Marseille (France)

    2014-10-15T23:59:59.000Z

    The study of biochemical dynamics by ultrafast spectroscopic methods is often restricted by the limited amount of liquid sample available, while the high repetition rate of light sources can induce photodamage. In order to overcome these limitations, we designed a high flux, sub-ml, capillary flow-cell. While the 0.1 mm thin window of the 0.5 mm cross-section capillary ensures an optimal temporal resolution and a steady beam deviation, the cell-pump generates flows up to ?0.35 ml/s that are suitable to pump laser repetition rates up to ?14 kHz, assuming a focal spot-diameter of 100 ?m. In addition, a decantation chamber efficiently removes bubbles and allows, via septum, for the addition of chemicals while preserving the closed atmosphere. The minimal useable amount of sample is ?250 ?l.

  14. MICROSCALE METABOLIC, REDOX AND ABIOTIC REACTIONS IN HANFORD 300 AREA SUBSURFACE SEDIMENTS

    SciTech Connect (OSTI)

    Beyenal, Haluk [WSU] [WSU; McLEan, Jeff [JCVI] [JCVI; Majors, Paul [PNNL] [PNNL; Fredrickson, Jim [PNNL] [PNNL

    2013-11-14T23:59:59.000Z

    The Hanford 300 Area is a unique site due to periodic hydrologic influence of river water resulting in changes in groundwater elevation and flow direction. This area is also highly subject to uranium remobilization, the source of which is currently believed to be the region at the base of the vadose zone that is subject to period saturation due to the changes in the water levels in the Columbia River. We found that microbial processes and redox and abiotic reactions which operate at the microscale were critical to understanding factors controlling the macroscopic fate and transport of contaminants in the subsurface. The combined laboratory and field research showed how microscale conditions control uranium mobility and how biotic, abiotic and redox reactions relate to each other. Our findings extended the current knowledge to examine U(VI) reduction and immobilization using natural 300 Area communities as well as selected model organisms on redox-sensitive and redox-insensitive minerals. Using innovative techniques developed specifically to probe biogeochemical processes at the microscale, our research expanded our current understanding of the roles played by mineral surfaces, bacterial competition, and local biotic, abiotic and redox reaction rates on the reduction and immobilization of uranium.

  15. a-dependent redox biology: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Waters Outline: 1. Redox chemistry 2. Redox potential in aquatic systems 3. Eutrophication 4. Water treatment 1. Redox chemistry 15; Principle of equilibration of chemical...

  16. auto-protective redox buffering: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Waters Outline: 1. Redox chemistry 2. Redox potential in aquatic systems 3. Eutrophication 4. Water treatment 1. Redox chemistry 15; Principle of equilibration of chemical...

  17. Effect of direct liquid water injection and interdigitated flow field on the performance of proton exchange membrane fuel cells

    E-Print Network [OSTI]

    Wood, D. L.; Yi, Y. S.; Van Nguyen, Trung

    1998-01-01T23:59:59.000Z

    Proper water management is vital to ensuring successful performance of proton exchange membrane fuel cells. The effectiveness of the direct liquid water injection scheme and the interdigitated flow field design towards providing adequate gas...

  18. MEMBRANELESS FUEL CELL BASED ON LAMINAR FLOW Eric R. Choban, Piotr Waszczuk, Larry J. Markoski, Andrzej Wieckowski, and Paul J.A. Kenis*

    E-Print Network [OSTI]

    Kenis, Paul J. A.

    MEMBRANELESS FUEL CELL BASED ON LAMINAR FLOW Eric R. Choban, Piotr Waszczuk, Larry J. Markoski in this area focus on downscaling of existing fuel cell technology such as the well-known proton exchange membrane (PEM) fuel cells. Here we study a novel concept for fuel cells: the use of laminar flow instead

  19. Fuel Cell Manufacturing Diagnostic Techniques: IR Thermography with Reactive Flow through Excitation

    SciTech Connect (OSTI)

    Manak, A. J.; Ulsh, M.; Bender, G.

    2012-01-01T23:59:59.000Z

    While design and material considerations for PEMFCs have a large impact on cost, it is also necessary to consider a transition to high volume production of fuel cell systems, including MEA components, to enable economies of scale and reduce per unit cost. One of the critical manufacturing tasks is developing and deploying techniques to provide in?process measurement of fuel cell components for quality control. This effort requires a subsidiary task: The study of the effect of manufacturing defects on performance and durability with the objective to establish validated manufacturing tolerances for fuel cell components. This work focuses on the development of a potential quality control method for gas diffusion electrodes (GDEs). The method consists of infrared (IR) thermography combined with reactive flow through (RFT) excitation. Detection of catalyst loading reduction defects in GDE catalyst layers will be presented.

  20. Redox, haem and CO in enzymatic catalysis and regulation

    E-Print Network [OSTI]

    Ragsdale, Stephen W.

    The present paper describes general principles of redox catalysis and redox regulation in two diverse systems. The first is microbial metabolism of CO by the Wood–Ljungdahl pathway, which involves the conversion of CO or ...

  1. Simulations of Blood Flow in Plain Cylindrical and Constricted Vessels with Single Cell Resolution

    E-Print Network [OSTI]

    Florian Janoschek; Federico Toschi; Jens Harting

    2011-05-31T23:59:59.000Z

    Understanding the physics of blood is challenging due to its nature as a suspension of soft particles and the fact that typical problems involve different scales. This is valid also for numerical investigations. In fact, many computational studies either neglect the existence of discrete cells or resolve relatively few cells very accurately. The authors recently developed a simple and highly efficient yet still particulate model with the aim to bridge the gap between currently applied methods. The present work focuses on its applicability to confined flows in vessels of diameters up to 100 micrometres. For hematocrit values below 30 percent, a dependence of the apparent viscosity on the vessel diameter in agreement with experimental literature data is found.

  2. 3D Modeling of One and Two Component Gas Flow in Fibrous Microstructures in Fuel Cells by Using the Lattice-Boltzmann Method

    E-Print Network [OSTI]

    Schmidt, Volker

    In fuel cells, a homogeneous distribution of gas flow is desirable for optimal performance. The gas3D Modeling of One and Two Component Gas Flow in Fibrous Microstructures in Fuel Cells by Using: Fuel Cells, 52425 Jülich, Germany b Institute of Stochastics, Ulm University, 89069 Ulm, Germany

  3. Co-flow anode/cathode supply heat exchanger for a solid-oxide fuel cell assembly

    DOE Patents [OSTI]

    Haltiner, Jr., Karl J.; Kelly, Sean M.

    2005-11-22T23:59:59.000Z

    In a solid-oxide fuel cell assembly, a co-flow heat exchanger is provided in the flow paths of the reformate gas and the cathode air ahead of the fuel cell stack, the reformate gas being on one side of the exchanger and the cathode air being on the other. The reformate gas is at a substantially higher temperature than is desired in the stack, and the cathode gas is substantially cooler than desired. In the co-flow heat exchanger, the temperatures of the reformate and cathode streams converge to nearly the same temperature at the outlet of the exchanger. Preferably, the heat exchanger is formed within an integrated component manifold (ICM) for a solid-oxide fuel cell assembly.

  4. Particle-in-Cell Modeling of Magnetized Argon Plasma Flow Through Small Mechanical Apertures

    SciTech Connect (OSTI)

    Adam B. Sefkow and Samuel A. Cohen

    2009-04-09T23:59:59.000Z

    Motivated by observations of supersonic argon-ion flow generated by linear helicon-heated plasma devices, a three-dimensional particle-in-cell (PIC) code is used to study whether stationary electrostatic layers form near mechanical apertures intersecting the flow of magnetized plasma. By self-consistently evaluating the temporal evolution of the plasma in the vicinity of the aperture, the PIC simulations characterize the roles of the imposed aperture and applied magnetic field on ion acceleration. The PIC model includes ionization of a background neutral-argon population by thermal and superthermal electrons, the latter found upstream of the aperture. Near the aperture, a transition from a collisional to a collisionless regime occurs. Perturbations of density and potential, with mm wavelengths and consistent with ion acoustic waves, propagate axially. An ion acceleration region of length ~ 200?300 ?D,e forms at the location of the aperture and is found to be an electrostatic double layer, with axially-separated regions of net positive and negative charge. Reducing the aperture diameter or increasing its length increases the double layer strength.

  5. Redox Shuttle Additives - Energy Innovation Portal

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's PossibleRadiation Protection RadiationRecord-SettingHead of Contracting ActivityRedox

  6. Fact Sheet: Vanadium Redox Flow Batteries (October 2012)

    Energy Savers [EERE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directed offOCHCO2: FinalOffers New Training on Energy ManagementAugustin2012) | Department ofFactTechnology

  7. Redox states of Desulfovibrio vulgaris DsrC, a key protein in dissimilatory sulfite reduction

    SciTech Connect (OSTI)

    Venceslau, Sofia S. [Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras (Portugal)] [Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras (Portugal); Cort, John R.; Baker, Erin S. [Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352 (United States)] [Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Chu, Rosalie K.; Robinson, Errol W. [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352 (United States)] [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Dahl, Christiane [Institut für Mikrobiologie and Biotechnologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Meckenheimer Allee 168, D-53115 Bonn (Germany)] [Institut für Mikrobiologie and Biotechnologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Meckenheimer Allee 168, D-53115 Bonn (Germany); Saraiva, Lígia M. [Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras (Portugal)] [Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras (Portugal); Pereira, Inês A.C., E-mail: ipereira@itqb.unl.pt [Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras (Portugal)

    2013-11-29T23:59:59.000Z

    Highlights: •DsrC is known to interact with the dissimilatory sulfite reductase enzyme (DsrAB). •We show that, however, most cellular DsrC is not associated with DsrAB. •A gel-shift assay was developed that allows monitoring of the DsrC redox state. •The DsrC intramolecularly oxidized state could only be produced by arginine treatment. -- Abstract: Dissimilatory reduction of sulfite is carried out by the siroheme enzyme DsrAB, with the involvement of the protein DsrC, which has two conserved redox-active cysteines. DsrC was initially believed to be a third subunit of DsrAB. Here, we report a study of the distribution of DsrC in cell extracts to show that, in the model sulfate reducer Desulfovibrio vulgaris, the majority of DsrC is not associated with DsrAB and is thus free to interact with other proteins. In addition, we developed a cysteine-labelling gel-shift assay to monitor the DsrC redox state and behaviour, and procedures to produce the different redox forms. The oxidized state of DsrC with an intramolecular disulfide bond, which is proposed to be a key metabolic intermediate, could be successfully produced for the first time by treatment with arginine.

  8. Thin graphite bipolar plate with associated gaskets and carbon cloth flow-field for use in an ionomer membrane fuel cell

    DOE Patents [OSTI]

    Marchetti, George A. (Western Springs, IL)

    2003-01-03T23:59:59.000Z

    The present invention comprises a thin graphite plate with associated gaskets and pieces of carbon cloth that comprise a flow-field. The plate, gaskets and flow-field comprise a "plate and gasket assembly" for use in an ionomer membrane fuel cell, fuel cell stack or battery.

  9. Factors Controlling Redox Speciation of Plutonium and Neptunium in Extraction Separation Processes

    SciTech Connect (OSTI)

    Paulenova, Alena [Principal Investigator; Vandegrift, III, George F. [Collaborator

    2013-09-24T23:59:59.000Z

    The objective of the project was to examine the factors controlling redox speciation of plutonium and neptunium in UREX+ extraction in terms of redox potentials, redox mechanism, kinetics and thermodynamics. Researchers employed redox-speciation extractions schemes in parallel to the spectroscopic experiments. The resulting distribution of redox species w studied uring spectroscopic, electrochemical, and spectro-electrochemical methods. This work reulted in collection of data on redox stability and distribution of redox couples in the nitric acid/nitrate electrolyte and the development of redox buffers to stabilize the desired oxidation state of separated radionuclides. The effects of temperature and concentrations on the redox behavior of neptunium were evaluated.

  10. Autocrine EGF receptor activation mediates endothelial cell migration and vascular morphogenesis induced by VEGF under interstitial flow

    SciTech Connect (OSTI)

    Semino, Carlos E. [Center for Biomedical Engineering and Biological Engineering Division, Massachusetts Institute of Technology, 77 Massachusetts Avenue, NE47-383, MIT, Cambridge, MA 02139 (United States)]. E-mail: semino@mit.edu; Kamm, Roger D. [Center for Biomedical Engineering and Biological Engineering Division, Massachusetts Institute of Technology, 77 Massachusetts Avenue, NE47-383, MIT, Cambridge, MA 02139 (United States); Lauffenburger, Douglas A. [Center for Biomedical Engineering and Biological Engineering Division, Massachusetts Institute of Technology, 77 Massachusetts Avenue, NE47-383, MIT, Cambridge, MA 02139 (United States)

    2006-02-01T23:59:59.000Z

    We show here that autocrine ligand activation of epidermal growth factor (EGF) receptor in combination with interstitial flow is critically involved in the morphogenetic response of endothelial cells to VEGF stimulation. Human umbilical vein endothelial cell (HUVEC) monolayers cultured on a collagen gel and exposed to low interstitial flow in the absence of EGF and VEGF remained viable and mitotic but exhibited little evidence of vascular morphogenesis. Addition of VEGF produced a flow-dependent morphogenetic response within 48 to 72 h, characterized by branched capillary-like structures. The response was substantially abolished by inhibitors related to the autocrine EGF receptor pathway including Galardin, AG1478, PD98059, and an EGF receptor-blocking antibody, indicating that regulation of the morphogenetic process operates via autocrine EGF receptor activation. Moreover, we observed that in our system the EGF receptor was always activated independently of the interstitial flow, and, in addition, the EGF receptor inhibitors used above reduced the phosphorylation state of the receptor, correlating with inhibition of capillary morphogenesis. Finally, 5'bromo-2'-deoxyuridine (BrdU) labeling identified dividing cells at the monolayer but not in the extending capillary-like structures. EGF pathway inhibitors Galardin and AG1478 did not reduce BrdU incorporation in the monolayer, indicating that the EGF-receptor-mediated morphogenetic behavior is mainly due to cell migration rather than proliferation. Based on these results, we propose a two-step model for in vitro capillary morphogenesis in response to VEGF stimulation with interstitial fluid flow: monolayer maintenance by mitotic activity independent of EGF receptors and a migratory response mediated by autocrine EGF receptor activation wherein cells establish capillary-like structures.

  11. Influence of Iron Redox Transformations on Plutonium Sorption...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and Pu(V) reduction demonstrates the potential impact of changing iron mineralogy on plutonium subsurface transport through redox transition areas. These findings...

  12. 5-Cyano-2,3-ditolyl tetrazolium chloride (CTC) reduction in a mesophilic anaerobic digester: Measuring redox behavior,

    E-Print Network [OSTI]

    Pace, Norman

    this work suggest that CTC reduction in cell-free samples may impede accurate enzyme activity measurements: Measuring redox behavior, differentiating abiotic reduction, and comparing FISH response as an activity). Dehydrogenase activity assays and fluorescent in situ hybridization (FISH) were simultaneously carried out

  13. Comparison of blood flow and cell function in ischemic skin flaps

    SciTech Connect (OSTI)

    Bean, D.; Rees, R.S.; O'Leary, J.P.; Lynch, J.B.

    1984-07-01T23:59:59.000Z

    Cellular function and blood flow in acute, steroid-treated, and surgically delayed random skin flaps have been examined. In these studies, the period following flap elevation could be divided into early (0-2 hr), intermediate (4-6 hr), and late (12 hr) periods of ischemia, based on the cutaneous blood flow and cellular function measured by thallium-201 uptake. There was a close correlation between blood flow and cellular function during the early period of ischemia which became worse with time. Blood flow studies demonstrated a significant difference between the early and intermediate periods of ischemia which was abolished by surgical delay. Improvement in cellular function was accomplished by improved blood flow in the surgically delayed flaps, while steroid-treated flaps enhanced cellular metabolism by another mechanism. Cellular function approximated blood flow during the early and immediate period of ischemia. Steroids may augment cellular function without improving blood flow, while surgical delay improves cellular function by improving blood flow.

  14. An acoustically-driven biochip - Impact of flow on the cell-association of targeted drug carriers

    E-Print Network [OSTI]

    Fillafer, Christian; Neumann, Jürgen; Guttenberg, Zeno; Dissauer, Silke; Lichtscheidl, Irene; Wirth, Michael; Gabor, Franz; Schneider, Matthias; 10.1039/B906006E

    2011-01-01T23:59:59.000Z

    The interaction of targeted drug carriers with epithelial and endothelial barriers in vivo is largely determined by the dynamics of the body fluids. To simulate these conditions in binding assays, a fully biocompatible in vitro model was developed which can accurately mimic a wide range of physiological flow conditions on a thumbnail-format cell-chip. This acoustically-driven microfluidic system was used to study the interaction characteristics of protein-coated particles with cells. Poly(D,L-lactide-co-glycolide) (PLGA) microparticles (2.86 {\\pm} 0.95 {\\mu}m) were conjugated with wheat germ agglutinin (WGA-MP, cytoadhesive protein) or bovine serum albumin (BSA-MP, nonspecific protein) and their binding to epithelial cell monolayers was investigated under stationary and flow conditions. While mean numbers of 1500 {\\pm} 307 mm-2 WGA-MP and 94 {\\pm} 64 mm-2 BSA-MP respectively were detected to be cell-bound in the stationary setup, incubation at increasing flow velocities increasingly antagonized the attachment...

  15. Real-Time Redox Measurements during Endoplasmic Reticulum Stress Reveal

    E-Print Network [OSTI]

    Mullins, Dyche

    Real-Time Redox Measurements during Endoplasmic Reticulum Stress Reveal Interlinked Protein Folding.10.011 SUMMARY Disruption of protein folding in the endoplasmic reticulum (ER) causes unfolded proteins to accumu is active. Because ER redox po- tential is optimized for oxidative protein folding, we reasoned

  16. Redox Transformations and Transport of Cesium and Iodine

    E-Print Network [OSTI]

    isotopes of cesium (137 Cs) and iodine (131 I and 129 I) are environmental contaminants derived fromRedox Transformations and Transport of Cesium and Iodine (-1, 0, +5) in Oxidizing and Reducing, to study the redox chemistry (I) and transport (Cs, I) of cesium and iodine in a field setting. Injection

  17. Biogeochemical Redox Processes and their Impact on Contaminant Dynamics

    E-Print Network [OSTI]

    Sparks, Donald L.

    reactions via the oxidation of labile organic carbon or inorganic compounds (electron donors often controls the release or sequestration of inorganic contaminants. Redox processes control Thebiogeochemicalcyclesofmanymajorandtraceelements are driven by redox processes. Examples include the cycles of carbon (C), nitrogen (N), sulfur (S

  18. Redox reactions of reduced flavin mononucleotide (FMN), riboflavin (RBF), and anthraquinone-2,6-disulfonate (AQDS) with ferrihydrite and lepidocrocite

    SciTech Connect (OSTI)

    Shi, Zhi; Zachara, John M.; Shi, Liang; Wang, Zheming; Moore, Dean A.; Kennedy, David W.; Fredrickson, Jim K.

    2012-11-01T23:59:59.000Z

    Flavins are secreted by the dissimilatory iron-reducing bacterium Shewanella and can function as endogenous electron transfer mediators (ETM). In order to assess the potential importance of flavins in Fe(III) bioreduction, we investigated the redox reaction kinetics of reduced flavins (FMNH2 and RBFH2) with ferrihydrite and lepidocrocite. The organic reductants rapidly reduced and dissolved ferrihydrite and lepidocrocite in the pH range 4-8. The rate constant k for 2-line ferrihydrite reductive dissolution by FMNH2 was 87.5 ? 3.5 M-1?s-1 at pH 7.0 in batch reactors, and the k was similar for RBFH2. For lepidocrocite, the k was 500 ? 61 M-1?s-1 for FMNH2, and 236 ? 22 M-1?s-1 for RBFH2. The surface area normalized initial reaction rates (ra) were between 0.08 and 77 ?moles?m-2?s-1 for various conditions in stopped-flow experiments. Initial rates (ro) were first-order with respect to Fe(III) oxide concentration, and ra increased with decreasing pH. Poorly crystalline 2-line ferrihydrite yielded the highest ra, followed by more crystalline 6-line ferrihydrite, and crystalline lepidocrocite. Compared to a previous whole-cell study with Shewanella oneidensis strain MR-1, our findings suggest that ETM reduction by the Mtr pathway coupled to lactate oxidation are rate limiting, rather than heterogeneous electron transfer to the Fe(III) oxide.

  19. Redox states of Desulfovibrio vulgaris DsrC, a key protein in dissimilatory sulfite reduction

    SciTech Connect (OSTI)

    Venceslau, Sofia S.; Cort, John R.; Baker, Erin Shammel; Chu, Rosalie K.; Robinson, Errol W.; Dahl, Christiane; Saraiva, Ligia M.; Pereira, Ines Ac

    2013-11-29T23:59:59.000Z

    Dissimilatory reduction of sulfite is carried out by the siroheme enzyme DsrAB, with the involvement of the protein DsrC having two conserved cysteine residues. Here, we report a study of the distribution of DsrC in cell extracts, a cysteine-labelling gel-shift assay to monitor its redox state and behaviour, and procedures to produce the different redox forms. We show that, in the model sulfate reducer Desulfovibrio vulgaris, the majority of DsrC is not associated with DsrAB and is thus free to interact with other proteins. In addition, we successfully produced DsrC with an intramolecular disulfide bond (oxidized state) by treatment with arginine.

  20. Anaerobic Redox Cycling of Iron by Freshwater Sediment Microorganisms

    SciTech Connect (OSTI)

    Weber, Karrie A.; Urrutia, Matilde M.; Churchill, Perry F.; Kukkadapu, Ravi K.; Roden, Eric E.

    2006-01-01T23:59:59.000Z

    The potential for microbially-mediated anaerobic redox cycling of iron (Fe) was examined in a first-generation enrichment culture of freshwater wetland sediment microorganisms. MPN enumerations revealed the presence of significant populations of Fe(III)-reducing (ca. 108 cells mL-1) and Fe(II)-oxidizing, nitrate-reducing organisms (ca. 105 cells mL-1) in the sediment used to inoculate the enrichment cultures. Nitrate reduction commenced immediately following inoculation of acetate-containing (ca. 1 mM) medium with a small quantity (1% vol/vol) of wetland sediment, and resulted in the transient accumulation of NO2- and production of a mixture of end-products including NH4+. Fe(III) oxide (high surface area goethite) reduction took place - after NO3- was depleted and continued until all the acetate was utilized. Addition of NO3 after Fe(III) reduction ceased resulted in the immediate oxidation of Fe(II) coupled to reduction of + NO3-to NH4 . No significant NO2- accumulation was observed during nitrate-dependent Fe(II) oxidation. No Fe(II) oxidation occurred in pasteurized controls. Microbial community structure in the enrichment was monitored by DGGE analysis of PCR amplified 16s rDNA and RT-PCR amplified 16S rRNA, as well as by construction of 16S rDNA clone libraries for four different time points during the experiment. Strong similarities in dominant members of the microbial community were observed in the Fe(III) reduction and nitrate-dependent Fe(II) oxidation phases of the experiment, specifically the common presence of organisms closely related (= 95% sequence similarity) to the genera Geobacter and Dechloromonas. These results indicate that the wetland sediments contained organisms such as Geobacter sp. which are capable of both + dissimilatory Fe(III) reduction and oxidation of Fe(II) with reduction of NO3-reduction to NH4 . Our findings suggest that microbially-catalyzed nitrate-dependent Fe(II) oxidation has the potential to contribute to a dynamic anaerobic Fe redox cycle in freshwater sediments.

  1. Methane oxidation over dual redox catalysts

    SciTech Connect (OSTI)

    Klier, K.; Herman, R.G.; Sojka, Z.; DiCosimo, J.I.; DeTavernier, S.

    1992-06-01T23:59:59.000Z

    Catalytic oxidation of methane to partial oxidation products, primarily formaldehyde and C[sub 2] hydrocarbons, was found to be directed by the catalyst used. In this project, it was discovered that a moderate oxidative coupling catalyst for C[sub 2] hydrocarbons, zinc oxide, is modified by addition of small amounts of Cu and Fe dopants to yield fair yields of formaldehyde. A similar effect was observed with Cu/Sn/ZnO catalysts, and the presence of a redox Lewis acid, Fe[sup III] or Sn[sup IV], was found to be essential for the selectivity switch from C[sub 2] coupling products to formaldehyde. The principle of double doping with an oxygen activator (Cu) and the redox Lewis acid (Fe, Sn) was pursued further by synthesizing and testing the CuFe-ZSM-5 zeolite catalyst. The Cu[sup II](ion exchanged) Fe[sup III](framework)-ZSM-5 also displayed activity for formaldehyde synthesis, with space time yields exceeding 100 g/h-kg catalyst. However, the selectivity was low and earlier claims in the literature of selective oxidation of methane to methanol over CuFe-ZSM-5 were not reproduced. A new active and selective catalytic system (M=Sb,Bi,Sn)/SrO/La[sub 2]O[sub 3] has been discovered for potentially commercially attractive process for the conversion of methane to C[sub 2] hydrocarbons, (ii) a new principle has been demonstrated for selectivity switching from C[sub 2] hydrocarbon products to formaldehyde in methane oxidations over Cu,Fe-doped zinc oxide and ZSM-5, and (iii) a new approach has been initiated for using ultrafine metal dispersions for low temperature activation of methane for selective conversions. Item (iii) continues being supported by AMOCO while further developments related to items (i) and (ii) are the objective of our continued effort under the METC-AMOCO proposed joint program.

  2. Novel, low-cost separator plates and flow-field elements for use in PEM fuel cells

    SciTech Connect (OSTI)

    Edlund, D.J. [Northwest Power Systems, LLC, Bend, OR (United States)

    1996-12-31T23:59:59.000Z

    PEM fuel cells offer promise for a wide range of applications including vehicular (e.g., automotive) and stationary power generation. The performance and cost targets that must be met for PEM technology to be commercially successful varies to some degree with the application. However, in general the cost of PEM fuel cell stacks must be reduced substantially if they are to see widespread use for electrical power generation. A significant contribution to the manufactured cost of PEM fuel cells is the machined carbon plates that traditionally serve as bipolar separator plates and flow-field elements. In addition, carbon separator plates are inherently brittle and suffer from breakage due to shock, vibration, and improper handling. This report describes a bifurcated separator device with low resistivity, low manufacturing cost, compact size and durability.

  3. Transport in a slowly perturbed convective cell flow. A. P. Itin 1 , R. de la Llave 2 , A. I. Neishtadt 1 , and A. A. Vasiliev 1

    E-Print Network [OSTI]

    Transport in a slowly perturbed convective cell flow. A. P. Itin 1 , R. de la Llave 2 , A. I in such flows may be very sensitive to initial conditions, making possible chaotic advection [6] of passive­scales (of order # # -3 ln#). In case of a generic perturbation, a drop of passive impurity (e.g. dye) put

  4. Effect in the KHT sarcoma of CCNU and MISO on cell cycle progression evaluated by flow-cytometry

    SciTech Connect (OSTI)

    Hill, S.A.; Bauer, K.D.; Keng, P.C.; Siemann, D.W.

    1984-09-01T23:59:59.000Z

    Previous studies using the KHT sarcoma have shown that misonidazole (MISO) enhances the cytotoxicity of 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU) by as much as a factor of 2.0. In the present study flow cytometry was used to monitor the changing DNA distributions of cells dissociated from solid tumors at successive times following treatment with CCNU, applied either alone or in combination with 0.5 mg/g MISO. The proportion of cells in late S and the G/sub 2/M phases of the cell cycle increased gradually after CCNU treatment. MISO did not significantly change this block in cell progression, which persisted for at least 48 hr after treatment in all cases. CCNU shows marked carbamoylating activity, which has been associated with inhibition of RNA processing and with the degree of chemopotentiation achieved with MISO. By 24 hr after treatment, CCNU clearly altered the distribution of RNA, but no significant differences could be detected between results obtained from drug and drug plus sensitizer treated groups. These studies demonstrate the effect of CCNU on cell cycle progression in vivo. The addition of MISO did not result in further perturbation of the total tumor population, suggesting that cell cycle redistribution does not play a major role in chemopotentiation by MISO.

  5. Current flow and efficiencies of concentrator InGaP/GaAs/Ge solar cells at temperatures below 300K

    SciTech Connect (OSTI)

    Kalinovsky, Vitaly S., E-mail: vitak.sopt@mail.ioffe.ru; Kontrosh, Evgeny V., E-mail: vitak.sopt@mail.ioffe.ru; Dmitriev, Pavel A., E-mail: vitak.sopt@mail.ioffe.ru; Pokrovsky, Pavel V., E-mail: vitak.sopt@mail.ioffe.ru; Chekalin, Alexander V., E-mail: vitak.sopt@mail.ioffe.ru; Andreev, Viacheslav M., E-mail: vitak.sopt@mail.ioffe.ru [Ioffe Physical-Technical Institute, St. Petersburg, Politekhicheskaya st. 26 (Russian Federation)

    2014-09-26T23:59:59.000Z

    The forward dark current density – voltage (J-V) characteristic is one of the most important characteristics of multi-junction solar cells. It indicates that the mechanisms of current flow in the space charge region of photoactive p-n junctions. If one is to idealize the optical and electrical (coupling) elements of the solar cells, it is the J-V characteristic that determines the theoretically possible efficiency of the solar cell. In this paper, using the connection between the dark J-V and photovoltaic (?-J{sub g}) efficiency – generated current density characteristics, the effect of current transport mechanisms in the space charge on the efficiency of multi-junction solar cells was investigated in the temperature range of 300 – 80 K. In the experimental J-V and ?-J{sub g} curves of the multi-junction solar cells, segments corresponding to the dominant current transport mechanisms were identified. The developed method, based on the analysis of forward dark J-V characteristics, makes it possible to identify the parameters affecting the efficiency of the multi-junction solar cells in a wide range of temperatures and solar radiation concentration.

  6. Study to establish cost projections for production of redox chemicals

    SciTech Connect (OSTI)

    Walther, J.F.; Greco, C.C.; Rusinko, R.N.; Wadsworth, A.L. III

    1982-11-01T23:59:59.000Z

    A cost study of four proposed manufacturing processes for redox chemicals for the NASA REDOX Energy Storage System yielded favorable selling prices in the range $0.99 to $1.91/kg of chromic chloride, anhydrous basis, including ferrous chloride. The prices corresponded to specific energy storage costs from under $9 to $17/kWh. A refined and expanded cost analysis of the most favored process yielded a price estimate corresponding to a storage cost of $11/kWh. The findings supported the potential economic viability of the NASA REDOX system.

  7. Mixing Cell Model: A One-Dimensional Numerical Model for Assessment of Water Flow and Contaminant Transport in the Unsaturated Zone

    SciTech Connect (OSTI)

    A. S. Rood

    2010-10-01T23:59:59.000Z

    This report describes the Mixing Cell Model code, a one-dimensional model for water flow and solute transport in the unsaturated zone under steady-state or transient flow conditions. The model is based on the principles and assumptions underlying mixing cell model formulations. The unsaturated zone is discretized into a series of independent mixing cells. Each cell may have unique hydrologic, lithologic, and sorptive properties. Ordinary differential equations describe the material (water and solute) balance within each cell. Water flow equations are derived from the continuity equation assuming that unit-gradient conditions exist at all times in each cell. Pressure gradients are considered implicitly through model discretization. Unsaturated hydraulic conductivity and moisture contents are determined by the material-specific moisture characteristic curves. Solute transport processes include explicit treatment of advective processes, first-order chain decay, and linear sorption reactions. Dispersion is addressed through implicit and explicit dispersion. Implicit dispersion is an inherent feature of all mixing cell models and originates from the formulation of the problem in terms of mass balance around fully mixed volume elements. Expressions are provided that relate implicit dispersion to the physical dispersion of the system. Two FORTRAN codes were developed to solve the water flow and solute transport equations: (1) the Mixing-Cell Model for Flow (MCMF) solves transient water flow problems and (2) the Mixing Cell Model for Transport (MCMT) solves the solute transport problem. The transient water flow problem is typically solved first by estimating the water flux through each cell in the model domain as a function of time using the MCMF code. These data are stored in either ASCII or binary files that are later read by the solute transport code (MCMT). Code output includes solute pore water concentrations, water and solute inventories in each cell and at each specified output time, and water and solute fluxes through each cell and specified output time. Computer run times for coupled transient water flow and solute transport were typically several seconds on a 2 GHz Intel Pentium IV desktop computer. The model was benchmarked against analytical solutions and finite-element approximations to the partial differential equations (PDE) describing unsaturated flow and transport. Differences between the maximum solute flux estimated by the mixing-cell model and the PDE models were typically less than two percent.

  8. Improving electricity production in tubular microbial fuel cells through optimizing the anolyte flow with spiral spacers

    E-Print Network [OSTI]

    Improving electricity production in tubular microbial fuel cells through optimizing the anolyte h l i g h t s " The spiral spacers improve electricity production in tubular microbial fuel cells fuel cells Spiral spacers Energy Wastewater treatment a b s t r a c t The use of spiral spacers

  9. Development of a novel in vitro model to study the tryptic : endothelial cells, monocytes and flow

    E-Print Network [OSTI]

    Turjman, Alexis S. (Alexis Salomon)

    2014-01-01T23:59:59.000Z

    This thesis describes the development of a novel in vitro model of monocytes transmigration under flow and use in the study of early molecular events of atherogenesis. In this work, we focused on how endothelial dysfunction, ...

  10. Anisotropic output-based adaptation with tetrahedral cut cells for compressible flows

    E-Print Network [OSTI]

    Park, Michael Andrew

    2008-01-01T23:59:59.000Z

    Anisotropic, adaptive meshing for flows around complex, three-dimensional bodies remains a barrier to increased automation in computational fluid dynamics. Two specific advances are introduced in this thesis. First, a ...

  11. Semi-Solid Flowable Battery Electrodes: Semi-Solid Flow Cells for Automotive and Grid-Level Energy Storage

    SciTech Connect (OSTI)

    2010-09-01T23:59:59.000Z

    BEEST Project: Scientists at 24M are crossing a Li-Ion battery with a fuel cell to develop a semi-solid flow battery. This system relies on some of the same basic chemistry as a standard Li-Ion battery, but in a flow battery the energy storage material is held in external tanks, so storage capacity is not limited by the size of the battery itself. The design makes it easier to add storage capacity by simply increasing the size of the tanks and adding more paste. In addition, 24M's design also is able to extract more energy from the semi-solid paste than conventional Li-Ion batteries. This creates a cost-effective, energy-dense battery that can improve the driving range of EVs or be used to store energy on the electric grid.

  12. Redox shuttles for overcharge protection of lithium batteries

    DOE Patents [OSTI]

    Amine, Khalil (Downers Grove, IL); Chen, Zonghai (Downers Grove, IL); Wang, Qingzheng (San Jose, CA)

    2010-12-14T23:59:59.000Z

    The present invention is generally related to electrolytes containing novel redox shuttles for overcharge protection of lithium-ion batteries. The redox shuttles are capable of thousands hours of overcharge tolerance and have a redox potential at about 3-5.5 V vs. Li and particularly about 4.4-4.8 V vs. Li. Accordingly, in one aspect the invention provides electrolytes comprising an alkali metal salt; a polar aprotic solvent; and a redox shuttle additive that is an aromatic compound having at least one aromatic ring with four or more electronegative substituents, two or more oxygen atoms bonded to the aromatic ring, and no hydrogen atoms bonded to the aromatic ring; and wherein the electrolyte solution is substantially non-aqueous. Further there are provided electrochemical devices employing the electrolyte and methods of making the electrolyte.

  13. Preparation of redox polymer cathodes for thin film rechargeable batteries

    DOE Patents [OSTI]

    Skotheim, T.A.; Lee, H.S.; Okamoto, Yoshiyuki.

    1994-11-08T23:59:59.000Z

    The present invention relates to the manufacture of thin film solid state electrochemical devices using composite cathodes comprising a redox polymer capable of undergoing oxidation and reduction, a polymer solid electrolyte and conducting carbon. The polymeric cathode material is formed as a composite of radiation crosslinked polymer electrolytes and radiation crosslinked redox polymers based on polysiloxane backbones with attached organosulfur side groups capable of forming sulfur-sulfur bonds during electrochemical oxidation.

  14. Experimental and Modeling Studies of Two-Phase Flow in Porous Media and Its Effects on the Performance of a PEM Fuel Cell

    E-Print Network [OSTI]

    Wang, Xuhai

    2010-01-01T23:59:59.000Z

    An experimental investigation was conducted to study the two-phase flow properties of porous media used in proton exchange membrane (PEM) fuel cells. The liquid and gas phase relative permeability of porous media used in PEM fuel cells was measured...

  15. Fe-phyllosilicate redox cycling organisms from a redox transition zone in Hanford 300 Area sediments

    SciTech Connect (OSTI)

    Benzine, Jason; Shelobolina, Evgenya S.; Xiong, Mai Yia; Kennedy, David W.; McKinley, James P.; Lin, Xueju; Roden, Eric E.

    2013-01-01T23:59:59.000Z

    Microorganisms capable of reducing or oxidizing structural iron (Fe) in Fe-bearing phyllosilicate minerals were enriched and isolated from a subsurface redox transition zone at the Hanford 300 Area site in eastern Washington, USA. Both conventional and in situ "i-chip" enrichment strategies were employed. One Fe(III)-reducing Geobacter (G. bremensis strain R1, Deltaproteobacteria) and six Fe(II) phyllosilicate-oxidizing isolates from the Alphaproteobacteria (Bradyrhizobium japonicum strains 22, is5, and in8p8), Betaproteobacteria (Cupriavidus necator strain A5-1, Dechloromonas agitata strain is5), and Actinobacteria (Nocardioides sp. strain in31) were recovered. The G. bremensis isolate grew by oxidizing acetate with the oxidized form of NAu-2 smectite as the electron acceptor. The Fe(II)-oxidizers grew by oxidation of chemically reduced smectite as the energy source with nitrate as the electron acceptor. The Bradyrhizobium isolates could also carry out aerobic oxidation of biotite. This is the first report of the recovery of a Fe(II)-oxidizing Nocardioides, and to date only one other Fe(II)-oxidizing Bradyrhizobium is known. The 16S rRNA gene sequences of the isolates were similar to ones found in clone libraries from Hanford 300 sediments and groundwater, suggesting that such organisms may be present and active in situ. Whole genome sequencing of the isolates is underway, the results of which will enable comparative genomic analysis of mechanisms of extracellular phyllosilicate Fe redox metabolism, and facilitate development of techniques to detect the presence and expression of genes associated with microbial phyllosilicate Fe redox cycling in sediments.

  16. Laminated exfoliated graphite composite-metal compositions for fuel cell flow field plate or bipolar plate applications

    DOE Patents [OSTI]

    Zhamu, Aruna; Shi, Jinjun; Guo, Jiusheng; Jang, Bor Z

    2014-05-20T23:59:59.000Z

    An electrically conductive laminate composition for fuel cell flow field plate or bipolar plate applications. The laminate composition comprises at least a thin metal sheet having two opposed exterior surfaces and a first exfoliated graphite composite sheet bonded to the first of the two exterior surfaces of the metal sheet wherein the exfoliated graphite composite sheet comprises: (a) expanded or exfoliated graphite and (b) a binder or matrix material to bond the expanded graphite for forming a cohered sheet, wherein the binder or matrix material is between 3% and 60% by weight based on the total weight of the first exfoliated graphite composite sheet. Preferably, the first exfoliated graphite composite sheet further comprises particles of non-expandable graphite or carbon in the amount of between 3% and 60% by weight based on the total weight of the non-expandable particles and the expanded graphite. Further preferably, the laminate comprises a second exfoliated graphite composite sheet bonded to the second surface of the metal sheet to form a three-layer laminate. Surface flow channels and other desired geometric features can be built onto the exterior surfaces of the laminate to form a flow field plate or bipolar plate. The resulting laminate has an exceptionally high thickness-direction conductivity and excellent resistance to gas permeation.

  17. A Finite Strain Model of Stress, Diffusion, Plastic Flow and Electrochemical Reactions in a Lithium-ion Half-cell

    E-Print Network [OSTI]

    Bower, Allan F; Sethuraman, Vijay A; 10.1016/j.jmps.2011.01.003

    2011-01-01T23:59:59.000Z

    We formulate the continuum field equations and constitutive equations that govern deformation, stress, and electric current flow in a Li-ion half-cell. The model considers mass transport through the system, deformation and stress in the anode and cathode, electrostatic fields, as well as the electrochemical reactions at the electrode/electrolyte interfaces. It extends existing analyses by accounting for the effects of finite strains and plastic flow in the electrodes, and by exploring in detail the role of stress in the electrochemical reactions at the electrode-electrolyte interfaces. In particular, we find that that stress directly influences the rest potential at the interface, so that a term involving stress must be added to the Nernst equation if the stress in the solid is significant. The model is used to predict the variation of stress and electric potential in a model 1-D half-cell, consisting of a thin film of Si on a rigid substrate, a fluid electrolyte layer, and a solid Li cathode. The predicted c...

  18. Microfabricated Renewable Beads-Trapping/Releasing Flow Cell for Rapid Antigen-Antibody Reaction in Chemiluminescent Immunoassay

    SciTech Connect (OSTI)

    Fu, Zhifeng; Shao, Guocheng; Wang, Jun; Lu, Donglai; Wang, Wanjun; Lin, Yuehe

    2011-04-01T23:59:59.000Z

    A filter pillar-array microstructure was coupled with a pneumatic micro-valve to fabricate a reusable miniaturized beads-trapping/releasing flow cell, in which trapping and releasing beads can be conveniently realized by switching the micro-valve. This miniaturized device was suitable to construct automatic fluidic system for “renewable surface analysis”. The renewable surface strategy based on pneumatic micro-valve enabled capture of beads in beads chamber prior to each assay, and release of the used beads after the assay. Chemiluminescent competitive immunoassay of 3,5,6-trichloropyridinol (TCP) was performed as a model to demonstrate the application potential of this reusable miniaturized flow cell. The whole fluidic assay process including beads trapping, immuno-binding, beads washing, beads releasing and signal collection could be completed in 10 min. Immunoassay of TCP using this miniaturized device showed a linear range of 0.20-70 ng/mL with a limit of detection of 0.080 ng/mL. The device had been successfully used for detection of TCP spiked in rat serum with average recovery of 97%. This investigation provides a rapid, sensitive, reusable, low-cost and automatic miniaturized device for solid-phase biochemical analysis for various purposes.

  19. Parallel flow in Hele-Shaw cells with ferrofluids Jose A. Miranda

    E-Print Network [OSTI]

    Widom, Michael

    a Kelvin- Helmholtz-Darcy equation and found the threshold for insta- bility was governed by inertial experimentally. Gondret and Rabaud 5 in- corporated inertial terms into the equation of motion in a Hele effects, while the wave veloc- ity was governed by Darcy's law flow of viscous fluids. Their experimental

  20. Renaissance in Flow-Cell Technologies Recent Advancements and Future Opportunities

    E-Print Network [OSTI]

    energy Limited life cycle Continuous self-discharge Conventional battery constraints Low round) Power out Electrode Electrode Energy and power independent Long life cycle Low self-discharge rates been demonstrated in field Technology is proven, but not cost effective · Flow Battery concept

  1. Multiscale Modeling of Red Blood Cell Mechanics and Blood Flow in Malaria

    E-Print Network [OSTI]

    Fedosov, Dmitry A.

    Red blood cells (RBCs) infected by a Plasmodium parasite in malaria may lose their membrane deformability with a relative membrane stiffening more than ten-fold in comparison with healthy RBCs leading to potential capillary ...

  2. Solid oxide fuel cell having monolithic cross flow core and manifolding

    DOE Patents [OSTI]

    Poeppel, R.B.; Dusek, J.T.

    1983-10-12T23:59:59.000Z

    This invention discloses a monolithic core construction having the flow passageways for the fuel and for the oxidant gases extended transverse to one another, whereby full face core manifolding can be achieved for these gases and their reaction products. The core construction provides that only anode material surround each fuel passageway and only cathode material surround each oxidant passageway, each anode and each cathode further sandwiching at spaced opposing sides electrolyte and interconnect materials to define electrolyte and interconnect walls. Webs of the cathode and anode material hold the electrolyte and interconnect walls spaced apart to define the flow passages. The composite anode and cathode wall structures are further alternately stacked on one another (with the separating electrolyte or interconnect material typically being a single common layer) whereby the fuel passageways and the oxidant passageways are disposed transverse to one another.

  3. Fuel cell assembly fluid flow plate having conductive fibers and rigidizing material therein

    DOE Patents [OSTI]

    Walsh, Michael M. (Fairfield, CT)

    2000-01-01T23:59:59.000Z

    A fluid flow plate is preferably formed with three initial sections, for instance, two layers of conductive (e.g., metal) fibers and a barrier material (e.g., metal foil) which is interposed between the two layers. For example, sintering of these three sections can provide electrical path(s) between outer faces of the two layers. Then, the sintered sections can be, for instance, placed in a mold for forming of flow channel(s) into one or more of the outer faces. Next, rigidizing material (e.g., resin) can be injected into the mold, for example, to fill and/or seal space(s) about a conductive matrix of the electrical path(s). Preferably, abrading of surface(s) of the outer face(s) serves to expose electrical contact(s) to the electrical path(s).

  4. Solid oxide fuel cell having monolithic cross flow core and manifolding

    DOE Patents [OSTI]

    Poeppel, Roger B. (Glen Ellyn, IL); Dusek, Joseph T. (Downers Grove, IL)

    1984-01-01T23:59:59.000Z

    This invention discloses a monolithic core construction having the flow passageways for the fuel and for the oxidant gases extended transverse to one another, whereby full face core manifolding can be achieved for these gases and their reaction products. The core construction provides that only anode material surround each fuel passageway and only cathode material surround each oxidant passageway, each anode and each cathode further sandwiching at spaced opposing sides electrolyte and interconnect materials to define electrolyte and interconnect walls. Webs of the cathode and anode material hold the electrolyte and interconnect walls spaced apart to define the flow passages. The composite anode and cathode wall structures are further alternately stacked on one another (with the separating electrolyte or interconnect material typically being a single common layer) whereby the fuel passageway and the oxidant passageways are disposed transverse to one another.

  5. In situ characterization of nanoscale catalysts during anodic redox processes

    SciTech Connect (OSTI)

    Sharma, Renu [National Institute of Standards and Technology] National Institute of Standards and Technology; Crozier, Peter [Arizona State University] Arizona State University; Adams, James [Arizona State University] Arizona State University

    2013-09-19T23:59:59.000Z

    Controlling the structure and composition of the anode is critical to achieving high efficiency and good long-term performance. In addition to being a mixed electronic and ionic conductor, the ideal anode material should act as an efficient catalyst for oxidizing hydrogen, carbon monoxide and dry hydrocarbons without de-activating through either sintering or coking. It is also important to develop novel anode materials that can operate at lower temperatures to reduce costs and minimized materials failure associated with high temperature cycling. We proposed to synthesize and characterize novel anode cermets materials based on ceria doped with Pr and/or Gd together with either a Ni or Cu metallic components. Ceria is a good oxidation catalyst and is an ionic conductor at room temperature. Doping it with trivalent rare earths such as Pr or Gd retards sintering and makes it a mixed ion conductor (ionic and electronic). We have developed a fundamental scientific understanding of the behavior of the cermet material under reaction conditions by following the catalytic oxidation process at the atomic scale using a powerful Environmental Scanning Transmission Electron Microscope (ESTEM). The ESTEM allowed in situ monitoring of structural, chemical and morphological changes occurring at the cermet under conditions approximating that of typical fuel-cell operation. Density functional calculations were employed to determine the underlying mechanisms and reaction pathways during anode oxidation reactions. The dynamic behavior of nanoscale catalytic oxidation of hydrogen and methane were used to determine: ? Fundamental processes during anodic reactions in hydrogen and carbonaceous atmospheres ? Interfacial effects between metal particles and doped ceria ? Kinetics of redox reaction in the anode material

  6. Lattice-Boltzmann Simulations of Multiphase Flows in Gas-Diffusion-Layer (GDL) of a PEM Fuel Cell

    SciTech Connect (OSTI)

    Shiladitya Mukherjeea; J. Vernon Cole; Kunal Jainb; Ashok Gidwania

    2008-11-01T23:59:59.000Z

    Improved power density and freeze-thaw durability in automotive applications of Proton Exchange Membrane Fuel Cells (PEMFCs) requires effective water management at the membrane. This is controlled by a porous hydrophobic gas-diffusion-layer (GDL) inserted between the membrane catalyst layer and the gas reactant channels. The GDL distributes the incoming gaseous reactants on the catalyst surface and removes excess water by capillary action. There is, however, limited understanding of the multiphase, multi-component transport of liquid water, vapor and gaseous reactants within these porous materials. This is due primarily to the challenges of in-situ diagnostics for such thin (200 -? 300 {microns}), optically opaque (graphite) materials. Transport is typically analyzed by fitting Darcy's Law type expressions for permeability, in conjunction with capillary pressure relations based on formulations derived for media such as soils. Therefore, there is significant interest in developing predictive models for transport in GDLs and related porous media. Such models could be applied to analyze and optimize systems based on the interactions between cell design, materials, and operating conditions, and could also be applied to evaluating material design concepts. Recently, the Lattice Boltzmann Method (LBM) has emerged as an effective tool in modeling multiphase flows in general, and flows through porous media in particular. This method is based on the solution of a discrete form of the well-known Boltzmann Transport Equation (BTE) for molecular distribution, tailored to recover the continuum Navier-Stokes flow. The kinetic theory basis of the method allows simple implementation of molecular forces responsible for liquid-gas phase separation and capillary effects. The solution advances by a streaming and collision type algorithm that makes it suitable to implement for domains with complex boundaries. We have developed both single and multiphase LB models and applied them to simulate flow through porous GDL materials. We will present an overview of the methods as implemented, verification studies for both microstructure reconstruction and transport simulations, and application to single- and two-phase transport in GDL structures. The applications studies are designed to both improve understanding of transport within a given structure, and to investigate possible routes for improving material properties through microstructure design.

  7. Generalized cell-centered finite volume methods: application to two-phase flow in porous media

    E-Print Network [OSTI]

    techniques have been used in nuclear engineering for the diffusion approximation and are called nodal methods hand, cell-centered finite volume methods are widely used by engineers and scien- tists who have., (John Wiley, Chichester, England,1997), pp. 231-241. #12;resulting schemes may be different from what

  8. Examination of protein degradation in continuous flow, microbial electrolysis cells treating fermentation wastewater

    E-Print Network [OSTI]

    16802, USA b Jeju Global Research Center, Korea Institute of Energy Research, 200 Haemajihaean-ro, Gujwa were 0.49 ± 0.05 m3 /m3 -d for the FWW, compared to 0.63 ± 0.02 m3 /m3 -d using a synthetic waste, including dark and light fermentation, and microbial electrolysis cells (MECs). Dark fermentation results

  9. Numerical Analysis of Cell Deformation of Twophase Flow with Discontinuous Viscosity and Nonlinear Surface Tension

    E-Print Network [OSTI]

    ­linear Surface Tension Zhilin Li and Sharon Lubkin Center For Research in Scientific Computation & Department equations, cell deformation, non­linear surface tension, jump conditions, interface, discontinuous and non boundary separating two fluids that have equal or different viscosity and non­linear surface tension

  10. Effects of Dioxin on Clock, Melatonin Biosynthetic, and Redox Sensitive Genes on Chick Pinealocytes In Vitro

    E-Print Network [OSTI]

    Hunt, Jayme

    2006-07-11T23:59:59.000Z

    shown to occur via redox dependent activity of nuclear factor 1 X-type (NF1X) and cellular redox potential can regulate the circadian clock. As such we hypothesized that exposure to dioxin could affect circadian rhythmicity. We explored...

  11. Testing the ancient marine redox record from oxygenic photosynthesis to photic zone euxina

    E-Print Network [OSTI]

    French, Katherine L. (Katherine Louise)

    2015-01-01T23:59:59.000Z

    Tracing the evolution of Earth's redox history is one of the great challenges of geobiology and geochemistry. The accumulation of photosynthetically derived oxygen transformed the redox state of Earth's surface environments, ...

  12. Metal-ligand redox interaction in the multielectron chemistry of porphyrinogen coordination compounds

    E-Print Network [OSTI]

    Bachmann, Julien

    2006-01-01T23:59:59.000Z

    Metal complexes of the macrocycle porphyrinogen (calix[4]pyrrole) are studied with an emphasis on the redox activity ("non-innocence") of the ligand (Chapter I). Porphyrinogen complexes of spherical, redox-inert metal ...

  13. DNA binding shifts the redox potential of the transcription factor SoxR

    E-Print Network [OSTI]

    Dietrich, Lars

    DNA binding shifts the redox potential of the transcription factor SoxR Alon A. Gorodetsky , Lars E-modified electrodes are used to probe the effects of binding to DNA on the redox potential of SoxR, a transcription in the absence of DNA. Using Redmond red as a covalently bound redox reporter affixed above the SoxR binding site

  14. Species-specific residues calibrate SoxR sensitivity to redox-active molecules

    E-Print Network [OSTI]

    Dietrich, Lars

    to viologens, which have redox potentials below -350 mV. Using a mutagenic approach, we pin- pointed threeSpecies-specific residues calibrate SoxR sensitivity to redox-active molecules Rebecca Sheplock,1, the transcription factor SoxR triggers a global stress response by sensing a broad spectrum of redox

  15. Versatile plug flow catalytic cell for in situ transmission/fluorescence x-ray absorption fine structure measurements

    SciTech Connect (OSTI)

    Centomo, P.; Zecca, M. [Dipartimento di Scienze Chimiche, via Marzolo 1, Universita degli Studi di Padova, 35131 Padova (Italy); Meneghini, C. [Dipartimento di Scienze, via della Vasca Navale 84, Universita di Roma TRE, 00146 Roma (Italy)

    2013-05-15T23:59:59.000Z

    A novel flow-through catalytic cell has been developed for in situ x-ray absorption spectroscopy (XAS) experiments on heterogeneous catalysts under working conditions and in the presence of a liquid and a gas phase. The apparatus allows to carry out XAS measurements in both the transmission and fluorescence modes, at moderate temperature (from RT to 50-80 Degree-Sign C) and low-medium gas pressure (up to 7-8 bars). The materials employed are compatible with several chemicals such as those involved in the direct synthesis of hydrogen peroxide (O{sub 2}, H{sub 2}, H{sub 2}O{sub 2}, methanol). The versatile design of the cell allows to fit it to different experimental setups in synchrotron radiation beamlines. It was used successfully for the first time to test nanostructured Pd catalysts during the direct synthesis of hydrogen peroxide (H{sub 2}O{sub 2}) in methanol solution from dihydrogen and dioxygen.

  16. A model for red blood cells in simulations of large-scale blood flows

    E-Print Network [OSTI]

    Simone Melchionna

    2011-07-25T23:59:59.000Z

    Red blood cells (RBCs) are an essential component of blood. A method to include the particulate nature of blood is introduced here with the goal of studying circulation in large-scale realistic vessels. The method uses a combination of the Lattice Boltzmann method (LBM) to account for the plasma motion, and a modified Molecular Dynamics scheme for the cellular motion. Numerical results illustrate the quality of the model in reproducing known rheological properties of blood as much as revealing the effect of RBC structuring on the wall shear stress, with consequences on the development of cardiovascular diseases.

  17. Fuel Cell with Metal Screen Flow-Field - Energy Innovation Portal

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power AdministrationField8,Dist.Newof Energy ForrestalPrinceton PlasmaEnergyFuel Cell with

  18. Redox Processes and Water Quality of Selected Principal Aquifer Systems

    E-Print Network [OSTI]

    . Similarly, the utilization of solid-phase electron acceptors such as Mn(IV) and Fe(III) is indicated observed at a regional scale. An important finding of this study was that samples indicating mixed redox such as dissolved ferrous iron (Fe21), hydrogen sulfide (H2S), and methane (CH4) (Back and Barnes 1965; Baedecker

  19. Adaptive changes in renal mitochondrial redox status in diabetic nephropathy

    SciTech Connect (OSTI)

    Putt, David A.; Zhong, Qing; Lash, Lawrence H., E-mail: l.h.lash@wayne.edu

    2012-01-15T23:59:59.000Z

    Nephropathy is a serious and common complication of diabetes. In the streptozotocin (STZ)-treated rat model of diabetes, nephropathy does not typically develop until 30 to 45 days post-injection, although hyperglycemia occurs within 24 h. We tested the hypothesis that chronic hyperglycemia results in a modest degree of oxidative stress that is accompanied by compensatory changes in certain antioxidants and mitochondrial redox status. We propose that as kidneys progress to a state of diabetic nephropathy, further adaptations occur in mitochondrial redox status. Basic parameters of renal function in vivo and several parameters of mitochondrial function and glutathione (GSH) and redox status in isolated renal cortical mitochondria from STZ-treated and age-matched control rats were examined at 30 days and 90 days post-injection. While there was no effect of diabetes on blood urea nitrogen, measurement of other, more sensitive parameters, such as urinary albumin and protein, and histopathology showed significant and progressive worsening in diabetic rats. Thus, renal function is compromised even prior to the onset of frank nephropathy. Changes in mitochondrial respiration and enzyme activities indicated existence of a hypermetabolic state. Higher mitochondrial GSH content and rates of GSH transport into mitochondria in kidneys from diabetic rats were only partially due to changes in expression of mitochondrial GSH carriers and were mostly due to higher substrate supply. Although there are few clear indicators of oxidative stress, there are several redox changes that occur early and change further as nephropathy progresses, highlighting the complexity of the disease. Highlights: ?Adaptive changes in renal mitochondrial and redox status in diabetic rats. ?Modest renal dysfunction even prior to onset of nephropathy. ?Elevated concentrations of mitochondrial GSH in diabetic kidneys. ?Change in GSH due partly to increased protein expression of transporter. ?Oxidatively modified proteins in renal mitochondria from diabetic rats.

  20. Dye-sensitized solar cell with a titanium-oxide-modified carbon nanotube transparent electrode

    E-Print Network [OSTI]

    Demir, Hilmi Volkan

    reaction limits their application as a working electrode in a liquid-type dye-sensitized solar cell (DSSC in a DSSC containing iodide/triiodide redox couples. This implementation is realized by inhibiting-sensitized solar cell (DSSC) to date because of their well-known catalytic property to redox reaction. Thus, it has

  1. Method of producing exfoliated graphite composite compositions for fuel cell flow field plates

    DOE Patents [OSTI]

    Zhamu, Aruna; Shi, Jinjun; Guo, Jiusheng; Jang, Bor Z

    2014-04-08T23:59:59.000Z

    A method of producing an electrically conductive composite composition, which is particularly useful for fuel cell bipolar plate applications. The method comprises: (a) providing a supply of expandable graphite powder; (b) providing a supply of a non-expandable powder component comprising a binder or matrix material; (c) blending the expandable graphite with the non-expandable powder component to form a powder mixture wherein the non-expandable powder component is in the amount of between 3% and 60% by weight based on the total weight of the powder mixture; (d) exposing the powder mixture to a temperature sufficient for exfoliating the expandable graphite to obtain a compressible mixture comprising expanded graphite worms and the non-expandable component; (e) compressing the compressible mixture at a pressure within the range of from about 5 psi to about 50,000 psi in predetermined directions into predetermined forms of cohered graphite composite compact; and (f) treating the so-formed cohered graphite composite to activate the binder or matrix material thereby promoting adhesion within the compact to produce the desired composite composition. Preferably, the non-expandable powder component further comprises an isotropy-promoting agent such as non-expandable graphite particles. Further preferably, step (e) comprises compressing the mixture in at least two directions. The method leads to composite plates with exceptionally high thickness-direction electrical conductivity.

  2. Predicting dynamics and rheology of blood flow: A comparative study of multiscale and low-dimensional models of red blood cells

    SciTech Connect (OSTI)

    Pan, Wenxiao; Fedosov, Dmitry A.; Caswell, Bruce; Karniadakis, George E.

    2011-05-27T23:59:59.000Z

    In this work we compare the predictive capability of two mathematical models for red blood cells (RBCs) focusing on blood flow in capillaries and arterioles. Both RBC models as well as their corresponding blood flows are based on the dissipative particle dynamics (DPD) method, a coarse-grained molecular dynamics approach. The first model employs a multiscale description of the RBC (MS-RBC), with its membrane represented by hundreds or even thousands of DPD-particles connected by springs into a triangular network in combination with out-of-plane elastic bending resistance. Extra dissipation within the network accounts for membrane viscosity, while the characteristic biconcave RBC shape is achieved by imposition of constraints for constant membrane area and constant cell volume. The second model is based on a low-dimensional description (LD-RBC) constructed as a closed torus-like ring of only 10 large DPD colloidal particles. They are connected into a ring by worm-like chain (WLC) springs combined with bending resistance. The LD-RBC model can be fitted to represent the entire range of nonlinear elastic deformations as measured by optical-tweezers for healthy and for infected RBCs in malaria. MS-RBCs suspensions model the dynamics and rheology of blood flow accurately for any size vessel but this approach is computationally expensive above 100 microns. Surprisingly, the much more economical suspensions of LD-RBCs also capture the blood flow dynamics and rheology accurately except for vessels with sizes comparable to RBC diameter. In particular, the LD-RBC suspensions are shown to properly capture the experimental data for the apparent viscosity of blood and its cell-free layer (CFL) in tube flow. Taken together, these findings suggest a hierarchical approach in modeling blood flow in the arterial tree, whereby the MS-RBC model should be employed for capillaries and arterioles below 100 microns, the LD-RBC model for arterioles, and the continuum description for arteries.

  3. Measuring Spatial Variability of Vapor Flux to Characterize Vadose-zone VOC Sources: Flow-cell Experiments

    SciTech Connect (OSTI)

    Mainhagu, Jon; Morrison, C.; Truex, Michael J.; Oostrom, Martinus; Brusseau, Mark

    2014-10-20T23:59:59.000Z

    A method termed vapor-phase tomography has recently been proposed to characterize the distribution of volatile organic contaminant mass in vadose-zone source areas, and to measure associated three-dimensional distributions of local contaminant mass discharge. The method is based on measuring the spatial variability of vapor flux, and thus inherent to its effectiveness is the premise that the magnitudes and temporal variability of vapor concentrations measured at different monitoring points within the interrogated area will be a function of the geospatial positions of the points relative to the source location. A series of flow-cell experiments was conducted to evaluate this premise. A well-defined source zone was created by injection and extraction of a non-reactive gas (SF6). Spatial and temporal concentration distributions obtained from the tests were compared to simulations produced with a mathematical model describing advective and diffusive transport. Tests were conducted to characterize both areal and vertical components of the application. Decreases in concentration over time were observed for monitoring points located on the opposite side of the source zone from the local–extraction point, whereas increases were observed for monitoring points located between the local–extraction point and the source zone. The results illustrate that comparison of temporal concentration profiles obtained at various monitoring points gives a general indication of the source location with respect to the extraction and monitoring points.

  4. Parallel flow diffusion battery

    DOE Patents [OSTI]

    Yeh, H.C.; Cheng, Y.S.

    1984-01-01T23:59:59.000Z

    A parallel flow diffusion battery for determining the mass distribution of an aerosol has a plurality of diffusion cells mounted in parallel to an aerosol stream, each diffusion cell including a stack of mesh wire screens of different density.

  5. Investigation of photoelectrode redox polymer junctions. Technical report, 16 November-15 January 1984

    SciTech Connect (OSTI)

    Cook, R.L.; Sammells, A.F.

    1985-01-15T23:59:59.000Z

    The n-CdS flatband potential in the solid-state cell n-CdS/Nafion 117 + redox species/Au was shifted progressively in a cathode directed upon the introduction of FeCp2, FeCp2 + Ru(bpy)3(2+) into the SPE. This cathodic shift was consistent with that for the oxidation potentials seen for Ru(bpy)3(2+) (E1/2 = 1.25V vs SCE) and FeCp2 (0.285V vs SCE) in acetonitrile. Such perturbations of semiconductor properties can be expected to form the basis of a detector technology when the semiconductor/SPE junction is exposed to selected chemical species.

  6. Vanadium and Chromium Redox Behavior in borosilicate Nuclear Waste Glasses

    SciTech Connect (OSTI)

    D McKeown; I Muller; H Gan; Z Feng; C Viragh; I Pegg

    2011-12-31T23:59:59.000Z

    X-ray absorption spectroscopy (XAS) was used to characterize vanadium (V) and chromium (Cr) environments in low activity nuclear waste (LAW) glasses synthesized under a variety of redox conditions. V{sub 2}O{sub 5} was added to the melt to improve sulfur incorporation from the waste; however, at sufficiently high concentrations, V increased melt foaming, which lowered melt processing rates. Foaming may be reduced by varying the redox conditions of the melt, while small amounts of Cr are added to reduce melter refractory corrosion. Three parent glasses were studied, where CO-CO{sub 2} mixtures were bubbled through the corresponding melt for increasing time intervals so that a series of redox-adjusted-glasses was synthesized from each parent glass. XAS data indicated that V and Cr behaviors are significantly different in these glasses with respect to the cumulative gas bubbling times: V{sup 4+}/V{sub total} ranges from 8 to 35%, while Cr{sup 3+}/Cr{sub total} can range from 15 to 100% and even to population distributions including Cr{sup 2+}. As Na-content decreased, V, and especially, Cr became more reduced, when comparing equivalent glasses within a series. The Na-poor glass series show possible redox coupling between V and Cr, where V{sup 4+} populations increase after initial bubbling, but as bubbling time increases, V{sup 4+} populations drop to near the level of the parent glass, while Cr becomes more reduced to the point of having increasing Cr{sup 2+} populations.

  7. Red blood cells and other non-spherical capsules in shear flow: oscillatory dynamics and the tank-treading-to-tumbling transition

    E-Print Network [OSTI]

    J. M. Skotheim; T. W. Secomb

    2006-05-26T23:59:59.000Z

    We consider the motion of red blood cells and other non-spherical microcapsules dilutely suspended in a simple shear flow. Our analysis indicates that depending on the viscosity, membrane elasticity, geometry and shear rate, the particle exhibits either tumbling, tank-treading of the membrane about the viscous interior with periodic oscillations of the orientation angle, or intermittent behavior in which the two modes occur alternately. For red blood cells, we compute the complete phase diagram and identify a novel tank-treading-to-tumbling transition at low shear rates. Observations of such motions coupled with our theoretical framework may provide a sensitive means of assessing capsule properties.

  8. Effective Panchromatic Sensitization of Electrochemical Solar Cells: Strategy and Organizational Rules for Spatial Separation of

    E-Print Network [OSTI]

    -neutral sources. Dye- sensitized solar cells (DSCs), comprising chromophores, redox shuttles, and nanoporousEffective Panchromatic Sensitization of Electrochemical Solar Cells: Strategy and Organizational National Laboratory, Argonne, Illinois 60439, United States *S Supporting Information ABSTRACT: Dye-sensitized

  9. SFTEL: Flow Cell | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Intermediate-scale Laboratory Experiments and Simulations. Soil desiccation (drying), involving water evaporation induced by dry gas injection, is a potentially robust...

  10. Redox Characterization of Proteins Involved in the Mitochondrial Intermembrane Space Pathway

    E-Print Network [OSTI]

    Neal, Sonya Elina

    2013-01-01T23:59:59.000Z

    Bardwell. 1999. Oxidative protein folding is driven by theRedox regulation of protein folding in the mitochondrial2008. Disulfide-linked protein folding pathways. Annu. Rev.

  11. The geochemistry of redox sensitive trace metals in sediments

    SciTech Connect (OSTI)

    Morford, J.L.; Emerson, S. [Univ. of Washington, Seattle, WA (United States). School of Oceanography] [Univ. of Washington, Seattle, WA (United States). School of Oceanography

    1999-06-01T23:59:59.000Z

    The authors analyzed the redox sensitive elements V, Mo, U, Re and Cd in surface sediments from the Northwest African margin, the US Northwest margin and the Arabian Sea to determine their response under a range of redox conditions. Where oxygen penetrates 1 cm or less into the sediments, Mo and V diffuse to the overlying water as Mn is reduced and remobilized. Authigenic enrichments of U, Re and Cd are evident under these redox conditions. With the onset of sulfate reduction, all of the metals accumulate authigenically with Re being by far the most enriched. General trends in authigenic metal accumulation are described by calculating authigenic fluxes for the 3 main redox regimes: oxic, reducing where oxygen penetrates {le} 1 cm, and anoxic conditions. Using a simple diagenesis model and global estimates of organic carbon rain rate and bottom water oxygen concentrations, the authors calculate the area of sediments below 1,000 m water depth in which oxygen penetration is {le} 1 cm to be 4% of the ocean floor. They conclude that sediments where oxygen penetrates {le} 1 cm release Mn, V and Mo to seawater at rates of 140%--260%, 60%--150% and 5%--10% of their respective riverine fluxes, using the authigenic metal concentrations and accumulation rates from this work and other literature. These sediments are sinks for Re, Cd and U, with burial fluxes of 70%--140%, 30%--80% and 20%--40%, respectively, of their dissolved riverine inputs. They modeled the sensitivity of the response of seawater Re, Cd and V concentrations to changes in the area of reducing sediments where oxygen penetrates {le} 1 cm. The analysis suggests a negligible change in seawater Re concentration, whereas seawater concentrations of Cd and V could have decreased and increased, respectively, by 5%--10% over 20 kyr if the area of reducing sediments increased by a factor of 2 and by 10%--20% if the area increased by a factor of 3. The concentration variations for a factor of 2 increase in the area of reducing sediments are at about the level of uncertainty of Cd/Ca and V/Ca ratios observed in foraminifera shells over the last 40 kyr. This implies that the area of reducing sediments in the ocean deeper than 1,000 m (4%) has not been greater than twice the present value in the recent past.

  12. Controlled Chemical Doping of Semiconductor Nanocrystals Using Redox Buffers

    SciTech Connect (OSTI)

    Engel, Jesse H.; Surendranath, Yogesh; Alivisatos, Paul

    2013-07-09T23:59:59.000Z

    Semiconductor nanocrystal solids are attractive materials for active layers in next-generation optoelectronic devices; however, their efficient implementation has been impeded by the lack of precise control over dopant concentrations. Herein we demonstrate a chemical strategy for the controlled doping of nanocrystal solids under equilibrium conditions. Exposing lead selenide nanocrystal thin films to solutions containing varying proportions of decamethylferrocene and decamethylferrocenium incrementally and reversibly increased the carrier concentration in the solid by 2 orders of magnitude from their native values. This application of redox buffers for controlled doping provides a new method for the precise control of the majority carrier concentration in porous semiconductor thin films.

  13. Flow-Through Microfluidic Device for High-Efficiency Transfection of Mammalian Cells through Combined Microelectroporation and Sonoporation 

    E-Print Network [OSTI]

    Longsine, Whitney Leigh

    2012-07-16T23:59:59.000Z

    than that of electroporation. Importantly, there was little difference in short term cell viability between the three methods (maintained at > 90 percent). The average transfection efficiency for electro-sonoporation was 81.25 percent and cell...

  14. Flow-Through Microfluidic Device for High-Efficiency Transfection of Mammalian Cells through Combined Microelectroporation and Sonoporation

    E-Print Network [OSTI]

    Longsine, Whitney Leigh

    2012-07-16T23:59:59.000Z

    In this study we are presenting a proof-of-concept microfluidic device that simultaneously applies the conditions required for microelectroporation and micro-sonoporation in a flow-through fashion that allows for high throughput, high efficiency...

  15. Neuron, Vol. 36, 11951210, December 19, 2002, Copyright 2002 by Cell Press Sustained Negative BOLD, Blood Flow and Oxygen

    E-Print Network [OSTI]

    , Blood Flow and Oxygen Consumption Response and Its Coupling to the Positive Response in the Human Brain Several previous human PET (Shulman et al., 1997;Minneapolis, Minnesota 55455 and others) and f

  16. Photocurrent generation by photosystem 1 integrated in crosslinked redox Adrian Badura,a

    E-Print Network [OSTI]

    Roegner, Matthias

    Photocurrent generation by photosystem 1 integrated in crosslinked redox hydrogels Adrian Badura on a gold electrode surface via an Os complex containing redox polymer hydrogel which simultaneously is used as immobilisation matrix and as electron donor for PS1. On addition of methyl viologen as sacrificial electron

  17. The Application of Flow Cytometry to Examine Damage Clearance in Stem Cells From Whole-Body Irradiated Mice

    SciTech Connect (OSTI)

    Marples, Brian; Kovalchuk, Olga; McGonagle, Michele; Martinez, Alvaro; Wilson, George, D.

    2010-02-26T23:59:59.000Z

    The bone marrow contains many types of cells. Approximately 1-2% of these cells are critical for life, these are the so-called ‘bone marrow stem cells’ which divide indefinitely to produce platelets, red blood cells and white blood cells. Death of the bone marrow stem cells results in a diminished ability of the organism to make new blood cell components and can be fatal without medical intervention, such as a bone marrow transplant. Bone marrow stem cells are considered to be particularly sensitive to radiation injury. Therefore, it is important to understand how these cells response to total body radiation exposure and how these cells can be protected from radiation damage. The aim of this project was to determine if these critical cells in the bone marrow are susceptible to short-term and long-term injury after a whole-body exposure to a sub-lethal low dose of ionizing radiation. The overall aims were to determine if the extent of injury produced by the sub-lethal radiation exposure would be cleared from the stem cells and therefore present no long- term genetic risk to the organism, or if the radiation injury persisted and had an adverse long-term consequences for the cell genome. This research question is of interest in order to define the risks to exposed persons after occupational, accidental or terrorism-related sub-lethal low-dose radiation exposures. The novel aspect of this project was the methodology used to obtain the bone marrow stem cell-like cells and examining the outcomes of sub-lethal low-dose radiation in a mammalian animal model. Four radiation treatments were used: single treatments of 0.01Gy, 0.1 Gy, 1 Gy and ten treatments of 0.1 Gy given over 10 days. Bone marrow stem cell-like cells were then harvested 6 hours, 24 hours and 24 days later. The levels of radiation-induced cell death, damage to DNA and permanent changes to cellular DNA were measured in the isolated stem cell-like cells after each radiation treatment and time point and then the results were compared. As expected, the largest radiation dose produced the greatest level of damage but a linear relationship did not exist between cellular effects and radiation dose. The low dose exposures appeared to be more efficient at producing damage than the highest dose when normalized for the initial extent of damage. Additionally, immune stimulation given prior to radiation exposure appeared to protect the critical bone marrow stem cell population from radiation injury. The data suggest that the response of bone marrow stem-cell like cells to radiation injury is dependent on the extent of the initial levels of damage and the effects of total-body low-dose exposures can not be predicted by extrapolating from high dose exposures. This research has provided new information about the radiation sensitivity of bone marrow stem cell-like cells following total-body exposures, and suggests that these critical cells might be more sensitive to radiation than more mature cells in the bone marrow. Further work is need with intermediate radiation doses to confirm this conclusion.

  18. An analysis of a back-fed porous electrode for the bromine/bromide redox reaction

    E-Print Network [OSTI]

    Van Zee, John William

    1982-01-01T23:59:59.000Z

    that of the front-fed electrode (compare Figs. 1 and 2) This reduction in electrode gap could decrease the cell's specific resistance by more than 25% in Zn/Hrl batteries if a relatively nonconducting complexing agent (3) is present in the electrolyte. (The... of the back-fed electrode Previous Steady State Analyses Previous steady state analyses of porous electrodes have been presented for diffusion electrodes and for electrodes with electrolyte flowing through them. Two classes of flow-through electrodes...

  19. Ab initio electronic structure calculation of the redox potentials of bacteriochlorophyll and bacteriopheophytin in solution

    SciTech Connect (OSTI)

    Zhang, L.Y.; Friesner, R.A. [Columbia Univ., New York, NY (United States)

    1995-11-02T23:59:59.000Z

    We have carried out self-consistent reaction field (SCRF) calculations on the bacteriochlorophyll (BChl) and bacteriopheophytin (BPh) molecules at the Hartree-Fock level using the ab initio electronic structure code PSGVB together with an accurate numerical Poisson-Boltzmann solver. These are by far the largest ab initio SCRF computations carried out to date. We calculate redox potentials of these molecules in DMF solution for several geometries and compare the results with experiments of Fajer and co-workers. While the absolute redox energies are substantially in error, due to neglect of electron correlation, the relative redox energies agree qualitatively with the experimental findings. Treatment of solvation is crucial in predicting the proper ordering of the BChl and BPh redox energies. These results have implications for calculation of redox energies of the chromophores in the photosynthetic reaction center. 23 refs., 2 figs., 2 tabs.

  20. A catalytic approach to estimate the redox potential of heme-peroxidases

    SciTech Connect (OSTI)

    Ayala, Marcela [Departamento de Ingenieria Celular y Biocatalisis, Instituto de Biotecnologia, Universidad Nacional Autonoma de Mexico, Cuernavaca, Morelos 62210 (Mexico)]. E-mail: maa@ibt.unam.mx; Roman, Rosa [Departamento de Ingenieria Celular y Biocatalisis, Instituto de Biotecnologia, Universidad Nacional Autonoma de Mexico, Cuernavaca, Morelos 62210 (Mexico); Vazquez-Duhalt, Rafael [Departamento de Ingenieria Celular y Biocatalisis, Instituto de Biotecnologia, Universidad Nacional Autonoma de Mexico, Cuernavaca, Morelos 62210 (Mexico)

    2007-06-08T23:59:59.000Z

    The redox potential of heme-peroxidases varies according to a combination of structural components within the active site and its vicinities. For each peroxidase, this redox potential imposes a thermodynamic threshold to the range of oxidizable substrates. However, the instability of enzymatic intermediates during the catalytic cycle precludes the use of direct voltammetry to measure the redox potential of most peroxidases. Here we describe a novel approach to estimate the redox potential of peroxidases, which directly depends on the catalytic performance of the activated enzyme. Selected p-substituted phenols are used as substrates for the estimations. The results obtained with this catalytic approach correlate well with the oxidative capacity predicted by the redox potential of the Fe(III)/Fe(II) couple.

  1. Nature Macmillan Publishers Ltd 1997 of composition, temperature, oxygen fugacity and pressure on their redox states. Contrib. Mineral.

    E-Print Network [OSTI]

    Dominey, Peter F.

    on their redox states. Contrib. Mineral. Petrol. 108, 82­92 (1991). 22. Eggler, D. H. & Lorand, J. P. Sulfides

  2. Lateral flow strip assay

    DOE Patents [OSTI]

    Miles, Robin R. (Danville, CA); Benett, William J. (Livermore, CA); Coleman, Matthew A. (Oakland, CA); Pearson, Francesca S. (Livermore, CA); Nasarabadi, Shanavaz L. (Livermore, CA)

    2011-03-08T23:59:59.000Z

    A lateral flow strip assay apparatus comprising a housing; a lateral flow strip in the housing, the lateral flow strip having a receiving portion; a sample collection unit; and a reagent reservoir. Saliva and/or buccal cells are collected from an individual using the sample collection unit. The sample collection unit is immersed in the reagent reservoir. The tip of the lateral flow strip is immersed in the reservoir and the reagent/sample mixture wicks up into the lateral flow strip to perform the assay.

  3. Methane oxidation over dual redox catalysts. Final report

    SciTech Connect (OSTI)

    Klier, K.; Herman, R.G.; Sojka, Z.; DiCosimo, J.I.; DeTavernier, S.

    1992-06-01T23:59:59.000Z

    Catalytic oxidation of methane to partial oxidation products, primarily formaldehyde and C{sub 2} hydrocarbons, was found to be directed by the catalyst used. In this project, it was discovered that a moderate oxidative coupling catalyst for C{sub 2} hydrocarbons, zinc oxide, is modified by addition of small amounts of Cu and Fe dopants to yield fair yields of formaldehyde. A similar effect was observed with Cu/Sn/ZnO catalysts, and the presence of a redox Lewis acid, Fe{sup III} or Sn{sup IV}, was found to be essential for the selectivity switch from C{sub 2} coupling products to formaldehyde. The principle of double doping with an oxygen activator (Cu) and the redox Lewis acid (Fe, Sn) was pursued further by synthesizing and testing the CuFe-ZSM-5 zeolite catalyst. The Cu{sup II}(ion exchanged) Fe{sup III}(framework)-ZSM-5 also displayed activity for formaldehyde synthesis, with space time yields exceeding 100 g/h-kg catalyst. However, the selectivity was low and earlier claims in the literature of selective oxidation of methane to methanol over CuFe-ZSM-5 were not reproduced. A new active and selective catalytic system (M=Sb,Bi,Sn)/SrO/La{sub 2}O{sub 3} has been discovered for potentially commercially attractive process for the conversion of methane to C{sub 2} hydrocarbons, (ii) a new principle has been demonstrated for selectivity switching from C{sub 2} hydrocarbon products to formaldehyde in methane oxidations over Cu,Fe-doped zinc oxide and ZSM-5, and (iii) a new approach has been initiated for using ultrafine metal dispersions for low temperature activation of methane for selective conversions. Item (iii) continues being supported by AMOCO while further developments related to items (i) and (ii) are the objective of our continued effort under the METC-AMOCO proposed joint program.

  4. Sorption of redox-sensitive elements: critical analysis

    SciTech Connect (OSTI)

    Strickert, R.G.

    1980-12-01T23:59:59.000Z

    The redox-sensitive elements (Tc, U, Np, Pu) discussed in this report are of interest to nuclear waste management due to their long-lived isotopes which have a potential radiotoxic effect on man. In their lower oxidation states these elements have been shown to be highly adsorbed by geologic materials occurring under reducing conditions. Experimental research conducted in recent years, especially through the Waste Isolation Safety Assessment Program (WISAP) and Waste/Rock Interaction Technology (WRIT) program, has provided extensive information on the mechanisms of retardation. In general, ion-exchange probably plays a minor role in the sorption behavior of cations of the above three actinide elements. Formation of anionic complexes of the oxidized states with common ligands (OH/sup -/, CO/sup - -//sub 3/) is expected to reduce adsorption by ion exchange further. Pertechnetate also exhibits little ion-exchange sorption by geologic media. In the reduced (IV) state, all of the elements are highly charged and it appears that they form a very insoluble compound (oxide, hydroxide, etc.) or undergo coprecipitation or are incorporated into minerals. The exact nature of the insoluble compounds and the effect of temperature, pH, pe, other chemical species, and other parameters are currently being investigated. Oxidation states other than Tc (IV,VII), U(IV,VI), Np(IV,V), and Pu(IV,V) are probably not important for the geologic repository environment expected, but should be considered especially when extreme conditions exist (radiation, temperature, etc.). Various experimental techniques such as oxidation-state analysis of tracer-level isotopes, redox potential measurement and control, pH measurement, and solid phase identification have been used to categorize the behavior of the various valence states.

  5. Redox control of electric melters with complex feed compositions. Part I: analytical methods and models

    SciTech Connect (OSTI)

    Bickford, D F; Diemer, Jr, R B

    1985-01-01T23:59:59.000Z

    The redox state of glass from electric melters with complex feed compositions is determined by balance between gases above the melt, and transition metals and organic compounds in the feed. Part I discusses experimental and computational methods of relating flowrates and other melter operating conditions to the redox state of glass, and composition of the melter offgas. Computerized thermodynamic computational methods are useful in predicting the sequence and products of redox reactions and in assessing individual process variations. Melter redox state can be predicted by combining monitoring of melter operating conditions, redox measurement of fused melter feed samples, and periodic redox measurement of product. Mossbauer spectroscopy, and other methods which measure Fe(II)/Fe(III) in glass, can be used to measure melter redox state. Part II develops preliminary operating limits for the vitrification of High-Level Radioactive Waste. Limits on reducing potential to preclude the accumulation of combustible gases, accumulation of sulfides and selenides, and degradation of melter components are the most critical. Problems associated with excessively oxidizing conditions, such as glass foaming and potential ruthenium volatility, are controlled when sufficient formic acid is added to adjust melter feed rheology.

  6. PEGylated Nanoceria as Radical Scavenger with Tunable Redox Chemistry...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    gas shift catalysis, chemical mechanical planarization (CMP), solid oxide fuel cells (SOFC), solar cells4 and high temperature oxidation protection coatings1. Recently, CNPs have...

  7. Highly conductive, multi-layer composite precursor composition to fuel cell flow field plate or bipolar plate

    DOE Patents [OSTI]

    Jang, Bor Z. (Centerville, OH); Zhamu, Aruna (Centerville, OH); Guo, Jiusheng (Centerville, OH)

    2011-02-15T23:59:59.000Z

    This invention provides a moldable, multiple-layer composite composition, which is a precursor to an electrically conductive composite flow field plate or bipolar plate. In one preferred embodiment, the composition comprises a plurality of conductive sheets and a plurality of mixture layers of a curable resin and conductive fillers, wherein (A) each conductive sheet is attached to at least one resin-filler mixture layer; (B) at least one of the conductive sheets comprises flexible graphite; and (C) at least one resin-filler mixture layer comprises a thermosetting resin and conductive fillers with the fillers being present in a sufficient quantity to render the resulting flow field plate or bipolar plate electrically conductive with a conductivity no less than 100 S/cm and thickness-direction areal conductivity no less than 200 S/cm.sup.2.

  8. Stable-isotope probe of nano-scale mineral-fluid redox interactions

    SciTech Connect (OSTI)

    Kavner, Abby

    2014-11-26T23:59:59.000Z

    The project examined how stable isotopes fractionate at an aqueous/solid interface during electrochemical reduction reactions. Measurements in a wide variety of metal deposition systems including Fe, Zn, Li, Mo, and Cu, have led to observations of large isotope fractionations which strongly vary as a function of rate and temperature. For the Fe, Zn, and Li systems, our electrochemical deposition methods provide the largest single-pass fractionation factors that are observed for these systems. Based on these and other experiments and theory showing and predicting significant and rate-dependent fractionations of isotopes at reacting interfaces, we have developed a simple statistical mechanics framework that predicts the kinetic isotope effect accompanying phase transformations in condensed systems. In addition, we have begun to extend our studies of mineral-fluid redox interactions to high pressures and temperatures in the diamond anvil cell. We performed a series of experiments to determine solubilities of Cu and Ni at elevated pressure and temperature conditions relevant to ore-formation.

  9. An Improved Equilibrium-Kinetics Speciation Algorithm For Redox...

    Open Energy Info (EERE)

    The REACT speciation model was coupled with the multidimensional nonisothermal multiphase flow and mass transport code TOUGH2, resulting in the general purpose reactive...

  10. Some lessons learned from 20 years in RedOx Flow Battery R&D

    E-Print Network [OSTI]

    balancing pressure (low p) Materials Novel nano-structured non- carbon electrodes Novel low cost option Now ubiquitous on all large wind farms Utilities understand them ­ and feed them Extensively must power itself and this imposes complex trade offs, e.g: High voltage couples and reactive

  11. Vanadium redox-flow batteries Installation at Ris for characterisation measurements

    E-Print Network [OSTI]

    and investigating distributed power systems. SYSLAB consists of two wind turbines, a pv-array, a diesel genset it provides different services to grid including smoothing of wind turbine output, load balancing and similar in August 2007. Power systems with high penetration of Wind energy/Renewable energy Renewable energy

  12. Nuclear Magnetic Resonance Studies on Vanadium(IV) Electrolyte Solutions for Vanadium Redox Flow Battery

    SciTech Connect (OSTI)

    Vijayakumar, M.; Burton, Sarah D.; Huang, Cheng; Li, Liyu; Yang, Zhenguo; Graff, Gordon L.; Liu, Jun; Hu, Jian Z.; Skyllas-Kazacos, Maria

    2010-11-15T23:59:59.000Z

    The vanadium (IV) electrolyte solutions with various vanadium concentrations are studied by variable temperature 1H and 17O Nuclear Magnetic Resonance (NMR) spectroscopy. The structure and kinetics of vanadium (IV) species in the electrolyte solutions are explored with respect to vanadium concentration and temperature. It was found that the vanadium (IV) species exist as hydrated vanadyl ion, i.e. [VO(H2O)5]2+ forming an octahedral coordination with vanadyl oxygen in the axial position and the remaining positions occupied by water molecules. This hydrated vanadyl ion structure is stable in vanadium concentrations up to 3M and in the temperature range of 240 to 340 K. The sulfate anions in the electrolyte solutions are found to be weekly bound to this hydrated vanadyl ion and occupies its second coordination sphere. The possible effects of these sulfate anions in proton and water exchange between vanadyl ion and solvent molecules are discussed based on 1H and 17O NMR results.

  13. Membranes Optimized for High Conductivity and Low Crossover of Redox Flow

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOnItemResearch > The EnergyCenter (LMI-EFRC)MaRIETechnologies |meetingsat

  14. Redox Flow Batteries for Grid-scale Energy Storage - Energy Innovation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's PossibleRadiation Protection RadiationRecord-SettingHead of Contracting Activity

  15. Photocurrent Enhancement by Multilayered Porphyrin Sensitizers in a Photoelectrochemical Cell

    E-Print Network [OSTI]

    Dinolfo, Peter H.

    be useful in dye-sensitized solar cells (DSSCs). We report on the photoelectrochemical responses scheme for use in photoelectrochemical cells. KEYWORDS: porphyrin, light harvesting, dye-sensitized solar nanocrystalline titania and I- / I3 - redox shuttle electrolyte, dye-sensitized solar cells (DSSCs) have become

  16. Consequences of redox-active phenazines on the physiology of the opportunistic pathogen Pseudomonas aeruginosa

    E-Print Network [OSTI]

    Kern, Suzanne E

    2013-01-01T23:59:59.000Z

    Phenazines are redox-active small molecules produced by bacteria. Although phenazines have been studied extensively for their roles as toxins, how phenazines benefit producing organisms is still being uncovered. Pseudomonas ...

  17. The role of Ncb5or in fatty acid metabolism and redox homeostasis

    E-Print Network [OSTI]

    Xu, Ming

    2011-12-31T23:59:59.000Z

    The endoplasmic reticulum (ER)-associated NADH cytochrome b5 oxidoreductase (Ncb5or) is widely distributed in animal tissues. It contains two redox domains that are homologous to microsomal cytochrome b5 (Cyb5A) at the N ...

  18. Molecular cloning and characterization of important stress and redox regulatory genes from Hydra vulgaris

    E-Print Network [OSTI]

    Dash, Bhagirathi

    2007-04-25T23:59:59.000Z

    In this research, important stress and redox regulatory genes present in Hydra vulgaris were isolated and characterized to facilitate our understanding of the evolution and mechanisms of stress response. H. vulgaris heat shock protein 70 (HvHSP70...

  19. Hybrid density functional calculations of redox potentials and formation energies of transition metal compounds

    E-Print Network [OSTI]

    Ceder, Gerbrand

    We compare the accuracy of conventional semilocal density functional theory (DFT), the DFT+U method, and the Heyd-Scuseria-Ernzerhof (HSE06) hybrid functional for structural parameters, redox reaction energies, and formation ...

  20. Transimination of Quinone Imines: A Mechanism for Embedding Exogenous Redox Activity into the Nucleosome

    E-Print Network [OSTI]

    Ye, Wenjie

    Aminophenols can redox cycle through the corresponding quinone imines to generate ROS. The electrophilic quinone imine intermediate can react with protein thiols as a mechanism of immobilization in vivo. Here, we describe ...

  1. Sandia Energy - EC Publications

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    with accompanying nonaqueous compatible membranes and flow cell designs for higher energy density redox flow batteries targeted to support increasing demands for stationary...

  2. Electrochemical cell operation and system

    DOE Patents [OSTI]

    Maru, Hansraj C. (Brookfield Center, CT)

    1980-03-11T23:59:59.000Z

    Thermal control in fuel cell operation is affected through sensible heat of process gas by providing common input manifolding of the cell gas flow passage in communication with the cell electrolyte and an additional gas flow passage which is isolated from the cell electrolyte and in thermal communication with a heat-generating surface of the cell. Flow level in the cell gas flow passage is selected based on desired output electrical energy and flow level in the additional gas flow passage is selected in accordance with desired cell operating temperature.

  3. Flow cytometry apparatus

    DOE Patents [OSTI]

    Pinkel, Daniel (Walnut Creek, CA)

    1991-01-01T23:59:59.000Z

    An obstruction across the flow chamber creates a one dimensional convergence of a sheath fluid. A passageway in the construction directs flat cells near to the area of one dimensional convergence in the sheath fluid to provide proper orientation of flat cells at fast rates.

  4. Redox reaction and foaming in nuclear waste glass melting

    SciTech Connect (OSTI)

    Ryan, J.L.

    1995-08-01T23:59:59.000Z

    This document was prepared by Pacific Northwest Laboratory (PNL) and is an attempt to analyze and estimate the effects of feed composition variables and reducing agent variables on the expected chemistry of reactions occurring in the cold cap and in the glass melt in the nuclear waste glass Slurry-fed, joule-heated melters as they might affect foaming during the glass-making process. Numerous redox reactions of waste glass components and potential feed additives, and the effects of other feed variables on these reactions are reviewed with regard to their potential effect on glass foaming. A major emphasis of this report is to examine the potential positive or negative aspects of adjusting feed with formic acid as opposed to other feed modification techniques including but not limited to use of other reducing agents. Feed modification techniques other than the use of reductants that should influence foaming behavior include control of glass melter feed pH through use of nitric acid. They also include partial replacement of sodium salts by lithium salts. This latter action (b) apparently lowers glass viscosity and raises surface tension. This replacement should decrease foaming by decreasing foam stability.

  5. 100-D Area In Situ Redox Treatability Test for Chromate-Contaminated Groundwater

    SciTech Connect (OSTI)

    Williams, Mark D.; Vermeul, Vincent R.; Szecsody, James E.; Fruchter, Jonathan S.

    2000-10-12T23:59:59.000Z

    A treatability test was conducted for the In Situ Redox Manipulation (ISRM) technology at the 100 D Area of the U. S. Department of Energy's Hanford Site. The target contaminant was dissolved chromate in groundwater. The ISRM technology creates a permeable subsurface treatment zone to reduce mobile chromate in groundwater to an insoluble form. The ISRM permeable treatment zone is created by reducing ferric iron to ferrous iron within the aquifer sediments, which is accomplished by injecting aqueous sodium dithionite into the aquifer and then withdrawing the reaction products. The goal of the treatability test was to create a linear ISRM barrier by injecting sodium dithionite into five wells. Well installation and site characterization activities began in spring 1997; the first dithionite injection took place in September 1997. The results of this first injection were monitored through the spring of 1998. The remaining four dithionite injections were carried out in May through July of 1998.These five injections created a reduced zone in the Hanford unconfined aquifer approximately 150 feet in length (perpendicular to groundwater flow) and 50 feet wide. The reduced zone extended over the thickness of the unconfined zone. Analysis of post-emplacement groundwater samples showed concentrations of chromate, in the reduced zone decreased from approximately 1.0 mg/L before the tests to below analytical detection limits (<0.007 mg/L). Chromate concentrations also declined in downgradient monitoring wells to as low as 0.020 mg/L. These data, in addition to results from pre-test reducible iron characterization, indicate the barrier should be effective for 20 to 25 years. The 100-D Area ISRM barrier is being expanded to a length of up to 2,300 ft to capture a larger portion of the chromate plume.

  6. A two-photoelectrode solid-state photoelectrochemical cell

    SciTech Connect (OSTI)

    Sammells, A.F.; Schmidt, S.K.

    1985-02-01T23:59:59.000Z

    This article describes a two photoelectrode solid-state photoelectrochemical cell which is able to produce photopotentials in excess of one voltage and possesses some inherent storage capacity. The storage capacity is presently limited by the low concentration and thin solid polymer electrolyte (SPE) redox layers used between the photoelectrode and the SPE membrane. The use of solid-electrolyte based photoelectrochemical cells provides a unique approach for the photoelectrochemical conversion and storage of selected redox species incorporated within the proximity of the semiconductor/solid electrolyte interface. It is expected that the described cell will be of potential value as not only a specialized storage device, but for specific detector applications.

  7. Structural insights into the modulation of the redox properties of two Geobacter sulfurreducens homologous triheme cytochromes.

    SciTech Connect (OSTI)

    Morgado, L.; Bruix, M.; Orshonsky, V.; Londer, Y. Y.; Duke, N. E. C.; Yang, X.; Pokkuluri, P. R.; Schiffer, M.; Salgueiro, C. A.; Biosciences Division; Univ. Nova de Lisboa; Insti. de Quimica-Fisica

    2008-09-01T23:59:59.000Z

    The redox properties of a periplasmic triheme cytochrome, PpcB from Geobacter sulfurreducens, were studied by NMR and visible spectroscopy. The structure of PpcB was determined by X-ray diffraction. PpcB is homologous to PpcA (77% sequence identity), which mediates cytoplasmic electron transfer to extracellular acceptors and is crucial in the bioenergetic metabolism of Geobacter spp. The heme core structure of PpcB in solution, probed by 2D-NMR, was compared to that of PpcA. The results showed that the heme core structures of PpcB and PpcA in solution are similar, in contrast to their crystal structures where the heme cores of the two proteins differ from each other. NMR redox titrations were carried out for both proteins and the order of oxidation of the heme groups was determined. The microscopic properties of PpcB and PpcA redox centers showed important differences: (1) the order in which hemes become oxidized is III-I-IV for PpcB, as opposed to I-IV-III for PpcA; (2) the redox-Bohr effect is also different in the two proteins. The different redox features observed between PpcB and PpcA suggest that each protein uniquely modulates the properties of their co-factors to assure effectiveness in their respective metabolic pathways. The origins of the observed differences are discussed.

  8. Functionalized Graphene Sheets as a Versatile Replacement for Platinum in Dye-Sensitized Solar Cells

    E-Print Network [OSTI]

    Aksay, Ilhan A.

    ) electrodes were tested for catalytic performance in dye-sensitized solar cells (DSSCs). By using ethyl) this residue must not disperse in the electrolyte. KEYWORDS: graphene, dye-sensitized solar cell, cobalt redox mediator, triiodide, sacrificial binder 1. INTRODUCTION Dye-sensitized solar cells (DSSCs

  9. Insertable fluid flow passage bridgepiece and method

    DOE Patents [OSTI]

    Jones, Daniel O. (Glenville, NV)

    2000-01-01T23:59:59.000Z

    A fluid flow passage bridgepiece for insertion into an open-face fluid flow channel of a fluid flow plate is provided. The bridgepiece provides a sealed passage from a columnar fluid flow manifold to the flow channel, thereby preventing undesirable leakage into and out of the columnar fluid flow manifold. When deployed in the various fluid flow plates that are used in a Proton Exchange Membrane (PEM) fuel cell, bridgepieces of this invention prevent mixing of reactant gases, leakage of coolant or humidification water, and occlusion of the fluid flow channel by gasket material. The invention also provides a fluid flow plate assembly including an insertable bridgepiece, a fluid flow plate adapted for use with an insertable bridgepiece, and a method of manufacturing a fluid flow plate with an insertable fluid flow passage bridgepiece.

  10. Piezoelectric axial flow microvalve

    SciTech Connect (OSTI)

    Gemmen, Randall; Thornton, Jimmy; Vipperman, Jeffrey S.; Clark, William W.

    2007-01-09T23:59:59.000Z

    This invention is directed to a fuel cell operable with a quantity of fuel and a quantity of an oxidizer to produce electrical power, the fuel cell including a fuel cell body including a labyrinth system structured to permit the fuel and the oxidizer to flow therethrough; at least a first catalyst in fluid communication with the labyrinth; and at least a first microvalve operably disposed within at least a portion of the labyrinth. The microvalve utilizes a deflectable member operable upon the application of a voltage from a voltage source. The microvalve includes an elongated flow channel formed therein and extending substantially longitudinally between the first and second ends to permit substantially longitudinal flow of the fluid therethrough and between the first and second ends; and the deflectable member disposed on the valve body, the deflectable member including at least a first piezoelectric portion that is piezoelectrically operable to deflect the deflectable member between an open position and a closed position upon the application of a voltage, the deflectable member in the closed position being operable to resist the flow of the fluid through the flow channel.

  11. Redox-linked conformational changes of a multiheme cytochrome from Geobacter sulfurreducens

    SciTech Connect (OSTI)

    Morgado, Leonor [Requimte - CQFB, Departamento de Quimica, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Bruix, Marta [Departamento de Espectroscopia y Estructura Molecular, Instituto de Quimica-Fisica 'Rocasolano', CSIC, Serrano 119, 28006 Madrid (Spain); Londer, Yuri Y. [Biosciences Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Pokkuluri, P. Raj [Biosciences Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Schiffer, Marianne [Biosciences Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Salgueiro, Carlos A. [Requimte - CQFB, Departamento de Quimica, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal)]. E-mail: csalgueiro@dq.fct.unl.pt

    2007-08-17T23:59:59.000Z

    Multiheme c-type cytochromes from members of the Desulfovibrionacea and Geobactereacea families play crucial roles in the bioenergetics of these microorganisms. Thermodynamic studies using NMR and visible spectroscopic techniques on tetraheme cytochromes c {sub 3} isolated from Desulfovibrio spp. and more recently on a triheme cytochrome from Geobacter sulfurreducens showed that the properties of each redox centre are modulated by the neighbouring redox centres enabling these proteins to perform energy transduction and thus contributing to cellular energy conservation. Electron/proton transfer coupling relies on redox-linked conformational changes that were addressed for some multiheme cytochromes from the comparison of protein structure of fully reduced and fully oxidised forms. In this work, we identify for the first time in a multiheme cytochrome the simultaneous presence of two different conformations in solution. This was achieved by probing the different oxidation stages of a triheme cytochrome isolated from G. sulfurreducens using 2D-NMR techniques. The results presented here will be the foundations to evaluate the modulation of the redox centres properties by conformational changes that occur during the reoxidation of a multiheme protein.

  12. Microfabricated capillary electrophoresis chip and method for simultaneously detecting multiple redox labels

    DOE Patents [OSTI]

    Mathies, Richard A. (Moraga, CA); Singhal, Pankaj (Berkeley, CA); Xie, Jin (Walnut Creek, CA); Glazer, Alexander N. (Orinda, CA)

    2002-01-01T23:59:59.000Z

    This invention relates to a microfabricated capillary electrophoresis chip for detecting multiple redox-active labels simultaneously using a matrix coding scheme and to a method of selectively labeling analytes for simultaneous electrochemical detection of multiple label-analyte conjugates after electrophoretic or chromatographic separation.

  13. J.F. ALLEN, K. ALEXCIEV AND G. HAKANSSON Regulation by redox signalling

    E-Print Network [OSTI]

    Allen, John F.

    ,5] confirms this suspicion, and shows that redox control over photo- synthesis genes is exerted by two new', phosphorylated on aspar- tate by transfer of a phosphate from its partner, RegB. RegB is a 'sensor kinase; the genes reside in just two operons. It has long been known that the photo- synthetic apparatus

  14. Redox Regulation of the Nutrient-sensitive Raptor-mTOR Pathway and Complex*

    E-Print Network [OSTI]

    Sabatini, David M.

    Redox Regulation of the Nutrient-sensitive Raptor-mTOR Pathway and Complex* Received, Whitehead Institute for Biomedical Research and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142 The raptor-mTOR protein complex is a key component of a nutrient-sensitive signaling pathway

  15. Quantification of rapid environmental redox processes with quick-scanning x-ray absorption

    E-Print Network [OSTI]

    Sparks, Donald L.

    Quantification of rapid environmental redox processes with quick-scanning x-ray absorption. Here we apply quick-scanning x-ray absorption spectroscopy (Q-XAS), at sub-second time that can be measured using x-ray absorption spectroscopy. arsenic extended x-ray absorption fine structure

  16. Redox Chemistry DOI: 10.1002/anie.200501192

    E-Print Network [OSTI]

    Weibel, Douglas B.

    them impractical as consumable anodes in coal fuel cells--the use of coal slurries in molten transition-metal ions, including FeIII , SnIV , CuII , and CeIV , oxidize coal slurries with an activation.[12,13] Although the electrolysis of coal slurries in the presence of transition-metal ions has been

  17. Effect of Reducing Groundwater on the Retardation of Redox-Sensitive Radionuclides

    SciTech Connect (OSTI)

    Hu, Q; Zavarin, M; Rose, T P

    2008-04-21T23:59:59.000Z

    Laboratory batch sorption experiments were used to investigate variations in the retardation behavior of redox-sensitive radionuclides. Water-rock compositions used during these experiments were designed to simulate subsurface conditions at the Nevada Test Site (NTS), where a suite of radionuclides were deposited as a result of underground nuclear testing. Experimental redox conditions were controlled by varying the oxygen content inside an enclosed glove box and by adding reductants into the testing solutions. Under atmospheric (oxidizing) conditions, the radionuclide distribution coefficients varied with the mineralogical composition of the sorbent and the water chemistry. Under reducing conditions, distribution coefficients showed marked increases for {sup 99}Tc and {sup 237}Np in devitrified tuff, but much smaller variations in alluvium, carbonate rock, and zeolitic tuff. This effect was particularly important for {sup 99}Tc, which tends to be mobile under oxidizing conditions. Unlike other redox-sensitive radionuclides, iodine sorption may decrease under reducing conditions when I{sup -} is the predominant species. Overall, sorption of U to alluvium, devitrified tuff, and zeolitic tuff under atmospheric conditions was less than in the glove-box tests. However, the mildly reducing conditions achieved here were not likely to result in substantial U(VI) reduction to U(IV). Sorption of Pu was not affected by the decreasing redox conditions achieved in this study, as the predominant sorbed Pu species in all conditions was expected to be the low-solubility and strongly sorbing Pu(OH){sub 4}. Depending on the aquifer lithology, the occurrence of reducing conditions along a groundwater flowpath could potentially contribute to the retardation of redox-sensitive radionuclides {sup 99}Tc and {sup 237}Np, which are commonly identified as long-term dose contributors in the risk assessment in various nuclear facilities.

  18. In Situ Redox Manipulation Proof-of-Principle Test at the Fort Lewis Logistics Center: Final Report

    SciTech Connect (OSTI)

    VR Vermeul; MD Williams; JC Evans; JE Szecsody; BN Bjornstad; TL Liikala

    2000-10-25T23:59:59.000Z

    Pacific Northwest National Laboratory (PNNL) conducted a proof-of-principle test at the Fort Lewis Logistics Center to determine the feasibility of using the In Situ Redox Manipulation (ISRM) technology for remediating groundwater contaminated with dissolved trichloroethylene (TCE). ISRM creates a permeable treatment zone in the subsurface to remediate redox-sensitive contaminants in groundwater. The permeable treatment zone is formed by injecting a chemical reducing agent (sodium dithionite with pH buffers) into the aquifer through a well to reduce the naturally occurring ferric iron in the sediments to ferrous iron. Once the reducing agent is injected and given sufficient time to react with aquifer sediments, residual chemicals and reaction products are withdrawn from the aquifer through the same well used for the injection. Redox-sensitive contaminants such as TCE, moving through the treatment zone under natural groundwater flow conditions, are destroyed. TCE is degraded via reductive dechlorination within the ISRM treatment zone to benign degradation products (i.e., acetylene, ethylene). Prior to the proof-of-principle field test, the ISRM technology was successfully demonstrated in laboratory experiments for the reductive dechlorination of dissolved TCE using sediments from the Fort Lewis site. The Logistics Center was placed on the National Priorities List in December 1989 because of TCE contamination in groundwater beneath the site. A Federal Facilities Agreement between the Army, the U.S. Environmental Protection Agency, and the Washington State Department of Ecology became effective in January 1990, and a Record of Decision (ROD) was signed in September 1990. The major components of the ROD included installation of two pump-and-treat systems for the upper aquifer and further investigation of the lower aquifer and other potential sources of contamination. The pump-and-treat systems became operational in August 1995. Fort Lewis asked PNNL to provide technical support in accelerating Installation Restoration Program site remediation and significantly reducing site life-cycle costs at the Logistics Center. In support of this program, ISRM was selected as an innovative technology for bench and field-scale demonstration. Emplacement of the ISRM treatment zone was accomplished through a series of four separate dithionite injection tests conducted between November 10, 1998 and March 29,2000. An extensive program of chemical monitoring was also performed before, during, and after each injection to evaluate the performance of ISRM. Prior to emplacement of the ISRM treatment zone, the site was extensively characterized with respect to geologic, hydrologic, and geochemical properties. Sediment core samples collected for the characterization studies were analyzed in bench-scale column tests at PNNL to determine reducible iron content. These site-specific hydrogeologic and geochemical data were used to develop the emplacement design of the pilot-scale (i.e., single injection well) ISRM treatment zone. Performance data obtained from the proof-of-principle test indicate that field-scale reductive dechlorination of TCE using the ISRM technology is feasible. A treatment zone was created in the subsurface that reduced TCE concentrations as much as 92% on the downgradient side of the reduced zone, from a background concentration of approximately 140 ppb to approximately 11 ppb. The appearance of the principal degradation product, acetylene, also confirmed that TCE destruction was occurring. Analysis of sediment samples collected from post-test boreholes showed a high degree of iron reduction, which helped to confirm the effectiveness of the treatment zone emplacement. Another important goal of the testing program was to provide assurances that chemical treatment of the subsurface did not result in undesirable secondary effects, including formation of toxic TCE degradation products, mobilization of trace elements, and degradation of hydraulic performance. Results obtained from the Fort Lewis ISRM proof-of-principle test, which are c

  19. High-Surface-Area Architectures for Improved Charge Transfer Kinetics at the Dark Electrode in Dye-Sensitized Solar Cells

    E-Print Network [OSTI]

    ABSTRACT: Dye-sensitized solar cell (DSC) redox shuttles other than triiodide/iodide have exhibited: dark electrode, inverse opal, dye cell, fill factor INTRODUCTION Dye-sensitized solar cells (DSCsHigh-Surface-Area Architectures for Improved Charge Transfer Kinetics at the Dark Electrode in Dye-Sensitized

  20. Differential expressions of cell cycle regulatory proteins and ERK1/2 characterize the proliferative smooth muscle cell phenotype induced by allylamine

    E-Print Network [OSTI]

    Jones, Sarah Anne Louise

    2004-09-30T23:59:59.000Z

    by redox mechanisms are c-Fos, c-Jun, nrf-2 and AP-1 [61]. Many of these transcription factors are involved in cell growth and differentiation. Not only are ROS implicated in cell growth, differentiation, and survival, ROS can also elicit apoptosis...

  1. Flow chamber

    DOE Patents [OSTI]

    Morozov, Victor (Manassas, VA)

    2011-01-18T23:59:59.000Z

    A flow chamber having a vacuum chamber and a specimen chamber. The specimen chamber may have an opening through which a fluid may be introduced and an opening through which the fluid may exit. The vacuum chamber may have an opening through which contents of the vacuum chamber may be evacuated. A portion of the flow chamber may be flexible, and a vacuum may be used to hold the components of the flow chamber together.

  2. Extraordinarily Efficient Conduction in a Redox-Active Ionic Liquid

    E-Print Network [OSTI]

    Verner K. Thorsmølle; Guido Rothenberger; Daniel Topgaard; Jan C. Brauer; Dai-Bin Kuang; Shaik M. Zakeeruddin; Björn Lindman; Michael Grätzel; Jacques-E. Moser

    2010-11-09T23:59:59.000Z

    Iodine added to iodide-based ionic liquids leads to extraordinarily efficient charge transport, vastly exceeding that expected for such viscous systems. Using terahertz time-domain spectroscopy, in conjunction with dc conductivity, diffusivity and viscosity measurements we unravel the conductivity pathways in 1-methyl-3-propylimidazolium iodide melts. This study presents evidence of the Grotthuss mechanism as a significant contributor to the conductivity, and provides new insights into ion pairing processes as well as the formation of polyiodides. The terahertz and transport results are reunited in a model providing a quantitative description of the conduction by physical diffusion and the Grotthuss bond-exchange process. These novel results are important for the fundamental understanding of conduction in molten salts and for applications where ionic liquids are used as charge-transporting media such as in batteries and dye-sensitized solar cells.

  3. Geological flows

    E-Print Network [OSTI]

    Yu. N. Bratkov

    2008-11-19T23:59:59.000Z

    In this paper geology and planetology are considered using new conceptual basis of high-speed flow dynamics. Recent photo technics allow to see all details of a flow, 'cause the flow is static during very short time interval. On the other hand, maps and images of many planets are accessible. Identity of geological flows and high-speed gas dynamics is demonstrated. There is another time scale, and no more. All results, as far as the concept, are new and belong to the author. No formulae, pictures only.

  4. Unveiling Surface Redox Charge Storage of Interacting Two-Dimensional Hetero-Nanosheets in Hierarchical Architectures

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Mahmood, Qasim [Department of Chemical Engineering, College of Engineering, Kyung Hee University (Republic of Korea); Bak, Seong-Min [Brookhaven National Laboratory (BNL), Upton, NY (United States); Kim, Min G. [Beamline Research Division, Pohang Accelerator Laboratory, Pohang (Republic of Korea); Yun, Sol [School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon (Republic of Korea); Yang, Xiao-Qing [Brookhaven National Laboratory (BNL), Upton, NY (United States); Shin, Hyeon S. [Department of Energy Engineering, Department of Chemistry, and Low Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology(UNIST) (Republic of Korea); Kim, Woo S. [Department of Chemical Engineering, College of Engineering, Kyung Hee University (Republic of Korea); Braun, Paul V. [Department of Materials Science and Engineering Materials Research Laboratory and Beckman Institute, University of Illinois at Urbana?Champaign, Urbana, Illinois (United States); Park, Ho S. [School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon (Republic of Korea)

    2015-04-08T23:59:59.000Z

    Two-dimensional (2D) heteronanosheets are currently the focus of intense study due to the unique properties that emerge from the interplay between two low-dimensional nanomaterials with different properties. However, the properties and new phenomena based on the two 2D heteronanosheets interacting in a 3D hierarchical architecture have yet to be explored. Here, we unveil the surface redox charge storage mechanism of surface-exposed WS2 nanosheets assembled in a 3D hierarchical heterostructure using in situ synchrotron X-ray absorption and Raman spectroscopic methods. The surface dominating redox charge storage of WS2 is manifested in a highly reversible and ultrafast capacitive fashion due to the interaction of heteronanosheets and the 3D connectivity of the hierarchical structure. In contrast, compositionally identical 2D WS2 structures fail to provide a fast and high capacitance with different modes of lattice vibration. The distinctive surface capacitive behavior of 3D hierarchically structured heteronanosheets is associated with rapid proton accommodation into the in-plane W–S lattice (with the softening of the E2g bands), the reversible redox transition of the surface-exposed intralayers residing in the electrochemically active 1T phase of WS2 (with the reversible change in the interatomic distance and peak intensity of W–W bonds), and the change in the oxidation state during the proton insertion/deinsertion process. This proposed mechanism agrees with the dramatic improvement in the capacitive performance of the two heteronanosheets coupled in the hierarchical structure.

  5. Radiation-induced non-equilibrium redox chemistry of plutonium: implications for environmental migration

    SciTech Connect (OSTI)

    Haschke, J M; Siekhaus, W J

    2009-02-11T23:59:59.000Z

    Static concentrations of plutonium oxidation states in solution and at surfaces in oxide-water systems are identified as non-equilibrium steady states. These kinetically controlled systems are described by redox cycles based on irreversible disproportionation of Pu(IV), Pu(V), and Pu(VI) in OH-bridged intermediate complexes and at OH-covered oxide surfaces. Steady state is fixed by continuous redox cycles driven by radioactivity-promoted electron-transfer and energetically favorable reactions of Pu(III) and Pu(VII) disproportionation products with H2O. A model based on the redox cycles accounts for the high steady-state [Pu] coexisting with Pu(IV) hydrous oxide at pH 0-15 and for predominance of Pu(V) and Pu(VI) in solution. The steady-state [Pu] depends on pH and the surface area of oxide in solution, but not on the initial Pu oxidation state. PuO{sub 2+x} formation is attributed to high Pu(V) concentrations existing at water-exposed oxide surfaces. Results infer that migration of Pu in an aqueous environment is controlled by kinetic factors unique to that site and that the predominant oxidation states in solution are Pu(V) and Pu(VI).

  6. EVALUATION OF AMENDMENTS FOR MENDING THE INSITU REDOX MANIPULATION (ISRM) BARRIER

    SciTech Connect (OSTI)

    PETERSEN, S.W.

    2006-02-07T23:59:59.000Z

    In May of 2004, the U.S. Department of Energy (DOE) Richland and Fluor Hanford requested technical assistance from DOE Headquarters EM-23 to provide a team of technical experts to evaluate likely chemical/biological amendments for mending the In Situ Redox Manipulation (ISRM) Barrier in the 100-D Area of the Hanford Site. This request was a follow-on to an earlier request for assistance regarding the cause of chromium (Cr) breakthrough and recommendations for mending the barrier (March 2004 workshop). This report provides written documentation of the team's findings and recommendations. In 1995, a plume of dissolved hexavalent chromium [Cr(VI)] was discovered along the Columbia River shoreline and in the 100-D Area. Between 1999 and 2003, a reactive barrier using the ISRM technology, was installed at a distance of 680 meters along the river to reduce the Cr(VI) in the groundwater. The ISRM technology creates a treatment zone within the aquifer by injection of sodium dithionite, a strong reducing agent that scavenges dissolved oxygen (DO) from the aquifer and reduces ferric iron [Fe(III)], related metals, and oxy-ions. Bench-scale and field-scale treatability tests were conducted to demonstrate proof-of principle and to estimate barrier longevity, calculated to be in excess of twenty years. However, several years after initial and secondary treatment, groundwater in approximately 17 wells has been found to contain elevated Cr concentrations. The March 2004 technical assistance team (TAT) identified potential causes of Cr breakthrough as likely related to physical and chemical heterogeneity within the aquifer (including loss of reductive capacity within preferential flow paths) and the presence of other oxidants (DO and nitrate) significantly affecting the reductive capacity of the treated aquifer. These aquifer characteristics may limit the ability of alternative amendments to extend the reducing capacity of the barrier. A 2001 Bechtel Hanford report and evaluation of the ISRM performance data and barrier longevity assessment corroborate the observations and findings of the March 2004 TAT. The March 2004 TAT recommended the collection of new aquifer characterization data in combination with the interpretation of existing data to develop a conceptual model of aquifer heterogeneity to enable design of the most appropriate barrier mending system. The current TAT was convened to examine the most promising amendment that could be applied to mend the ISRM barrier. The Technical Assistance Team (TAT) performed the following activities: (1) Evaluate the most appropriate single or combination of chemical/biological amendments suitable for increasing the reductive capacity of the ISRM barrier; (2) Evaluate the most practicable means of introducing chemical/biological amendments in the target zones along the current BRM barrier; (3) Provide recommendations for laboratory treatability-testing protocol development to evaluate the type and delivery mechanisms of amendments in the current ISRM barrier location. Sections of this report present analyses and recommendations of potential amendments and delivery options to improve performance of the ISRM barrier. The report covers the spectrum of passive barrier mending to chemical and biological amendments that have been shown to perform more efficiently in more active remedial design approaches. Because DOE/RL is considering significant aquifer characterization studies as additional time and cost investment to mending the barrier, the TAT strongly recommends that DOE/RL conduct cost-benefit analyses of alternative designs to mend the barrier. In this way, the value and extent of characterization studies, compared to passive amendment delivery, compared to engineering redesign, can be quantitatively estimated for decision-making purposes.

  7. Final Report - Crystal Settling, Redox, and High Temperature Properties of ORP HLW and LAW Glasses, VSL-09R1510-1, Rev. 0, dated 6/18/09

    SciTech Connect (OSTI)

    Kruger, Albert A.; Wang, C.; Gan, H.; Pegg, I. L.; Chaudhuri, M.; Kot, W.; Feng, Z.; Viragh, C.; McKeown, D. A.; Joseph, I.; Muller, I. S.; Cecil, R.; Zhao, W.

    2013-11-13T23:59:59.000Z

    The radioactive tank waste treatment programs at the U. S. Department of Energy (DOE) have featured joule heated ceramic melter technology for the vitrification of high level waste (HLW). The Hanford Tank Waste Treatment and Immobilization Plant (WTP) employs this same basic technology not only for the vitrification of HLW streams but also for the vitrification of Low Activity Waste (LAW) streams. Because of the much greater throughput rates required of the WTP as compared to the vitrification facilities at the West Valley Demonstration Project (WVDP) or the Defense Waste Processing Facility (DWPF), the WTP employs advanced joule heated melters with forced mixing of the glass pool (bubblers) to improve heat and mass transport and increase melting rates. However, for both HLW and LAW treatment, the ability to increase waste loadings offers the potential to significantly reduce the amount of glass that must be produced and disposed and, therefore, the overall project costs. This report presents the results from a study to investigate several glass property issues related to WTP HLW and LAW vitrification: crystal formation and settling in selected HLW glasses; redox behavior of vanadium and chromium in selected LAW glasses; and key high temperature thermal properties of representative HLW and LAW glasses. The work was conducted according to Test Plans that were prepared for the HLW and LAW scope, respectively. One part of this work thus addresses some of the possible detrimental effects due to considerably higher crystal content in waste glass melts and, in particular, the impact of high crystal contents on the flow property of the glass melt and the settling rate of representative crystalline phases in an environment similar to that of an idling glass melter. Characterization of vanadium redox shifts in representative WTP LAW glasses is the second focal point of this work. The third part of this work focused on key high temperature thermal properties of representative WTP HLW and LAW glasses over a wide range of temperatures, from the melter operating temperature to the glass transition.

  8. In situ reduction and oxidation of nickel from solid oxide fuel cells in a Titan ETEM

    E-Print Network [OSTI]

    Dunin-Borkowski, Rafal E.

    In situ reduction and oxidation of nickel from solid oxide fuel cells in a Titan ETEM A. Faes1, Denmark antonin.faes@epfl.ch Keywords: In situ ETEM, nickel oxide, reduction, RedOx, SOFC Solid Oxide Fuel. C. Singhal, K. Kendall, High Temperature Solid Oxide Fuel Cell - Fundamentals, Design

  9. A Glucose BioFuel Cell Implanted in Rats Philippe Cinquin1

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    A Glucose BioFuel Cell Implanted in Rats Philippe Cinquin1 *, Chantal Gondran2 , Fabien Giroud2 powerful ones, Glucose BioFuel Cells (GBFCs), are based on enzymes electrically wired by redox mediators applications. Citation: Cinquin P, Gondran C, Giroud F, Mazabrard S, Pellissier A, et al. (2010) A Glucose BioFuel

  10. 100-D Area In Situ Redox Treatability Test for Chromate-Contaminated Groundwater: FY 1998 Year-End Report

    SciTech Connect (OSTI)

    Williams, M.D.; Vermeul, V.R.; Szecsody, J.E.; Fruchter, J.S.; Cole, C.R.

    1999-04-15T23:59:59.000Z

    A treatability test was conducted for the In Situ Redox Manipulation (ISRM) technology at the US Department of Energy's Hanford, Washington 100D Area. The target contaminant was dissolved chromate [Cr(VI)] in groundwater. The ISRM technology involves creating a permeable subsurface treatment zone to reduce mobile chromate in groundwater to an insoluble form. The ISRM permeable treatment zone is created by reducing ferric iron [Fe(III)] to ferrous iron [Fe(II)] within the aquifer sediments. This is accomplished by injecting aqueous sodium dithionite into the aquifer and withdrawing the reaction products. The goal of the treatability test was to create a linear ISRM barrier by injecting sodium dithionite into five wells. Well installation and site characterization activities began in the spring of 1997. The first dithionite injection took place in September 1997. The results of this first injection were monitored through the spring of 1998; the remaining four dithionite injections were carried out in May through July of 1998. These five injections created a reduced zone in the Hanford unconfined aquifer 150 feet in length (perpendicular to groundwater flow) by 50 feet wide. The reduced zone extended over the thickness of the unconfined zone, which is approximately 15 feet. Analysis of recent groundwater sampling events shows that the concentrations of chromate [Cr(VI)] in groundwater in the reduced zone have been decreased from starting concentrations of approximately 900 ppb to below analytical detection limits (<7 ppb). Chromate concentrations are also declining in some downgradient monitoring wells. Laboratory analysis of iron in the soil indicates that the barrier should remain in place for approximately 20 to 25 years. These measurements will be confirmed by analysis of sediment cores in FY 1999.

  11. Superlattice photoelectrodes for photoelectrochemical cells

    DOE Patents [OSTI]

    Nozik, A.J.

    1985-07-03T23:59:59.000Z

    The application of superlattice semiconductors as photoelectrodes in photoelectrochemical energy conversion processes is described. The invention is comprised of a multiple quantum well, or superlattice, semiconductor positioned on a plate and encapsulated in an insulation material, except the top surface, which is left exposed. An opening in insulation exposes a portion of the plate. When the photoelectrochemical cell is immersed in a liquid electrolyte and exposed to solar radiation, a redox reaction occurs, producing gases such as hydrogen and oxygen from a water electrolyte, which bubble off the cathode and anode portions of the cell. (LEW)

  12. Filtration and Leach Testing for PUREX Cladding Sludge and REDOX Cladding Sludge Actual Waste Sample Composites

    SciTech Connect (OSTI)

    Shimskey, Rick W.; Billing, Justin M.; Buck, Edgar C.; Casella, Amanda J.; Crum, Jarrod V.; Daniel, Richard C.; Draper, Kathryn E.; Edwards, Matthew K.; Hallen, Richard T.; Kozelisky, Anne E.; MacFarlan, Paul J.; Peterson, Reid A.; Swoboda, Robert G.

    2009-03-02T23:59:59.000Z

    A testing program evaluating actual tank waste was developed in response to Task 4 from the M-12 External Flowsheet Review Team (EFRT) issue response plan (Barnes and Voke 2006). The test program was subdivided into logical increments. The bulk water-insoluble solid wastes that are anticipated to be delivered to the Hanford Waste Treatment and Immobilization Plant (WTP) were identified according to type such that the actual waste testing could be targeted to the relevant categories. Under test plan TP RPP WTP 467 (Fiskum et al. 2007), eight broad waste groupings were defined. Samples available from the 222S archive were identified and obtained for testing. Under this test plan, a waste testing program was implemented that included: • Homogenizing the archive samples by group as defined in the test plan. • Characterizing the homogenized sample groups. • Performing parametric leaching testing on each group for compounds of interest. • Performing bench-top filtration/leaching tests in the hot cell for each group to simulate filtration and leaching activities if they occurred in the UFP2 vessel of the WTP Pretreatment Facility. This report focuses on a filtration/leaching test performed using two of the eight waste composite samples. The sample groups examined in this report were the plutonium-uranium extraction (PUREX) cladding waste sludge (Group 3, or CWP) and reduction-oxidation (REDOX) cladding waste sludge (Group 4, or CWR). Both the Group 3 and 4 waste composites were anticipated to be high in gibbsite, thus requiring caustic leaching. WTP RPT 167 (Snow et al. 2008) describes the homogenization, characterization, and parametric leaching activities before benchtop filtration/leaching testing of these two waste groups. Characterization and initial parametric data in that report were used to plan a single filtration/leaching test using a blend of both wastes. The test focused on filtration testing of the waste and caustic leaching for aluminum, in the form of gibbsite, and its impact on filtration. The initial sample was diluted with a liquid simulant to simulate the receiving concentration of retrieved tank waste into the UFP2 vessel (< 10 wt% undissolved solids). Filtration testing was performed on the dilute waste sample and dewatered to a higher solids concentration. Filtration testing was then performed on the concentrated slurry. Afterwards, the slurry was caustic leached to remove aluminum present in the undissolved solid present in the waste. The leach was planned to simulate leaching conditions in the UFP2 vessel. During the leach, slurry supernate samples were collected to measure the dissolution rate of aluminum in the waste. After the slurry cooled down from the elevated leach temperature, the leach liquor was dewatered from the solids. The remaining slurry was rinsed and dewatered with caustic solutions to remove a majority of the dissolved aluminum from the leached slurry. The concentration of sodium hydroxide in the rinse solutions was high enough to maintain the solubility of the aluminum in the dewatered rinse solutions after dilution of the slurry supernate. Filtration tests were performed on the final slurry to compare to filtration performance before and after caustic leaching.

  13. Redox buffered hydrofluoric acid etchant for the reduction of galvanic attack during release etching of MEMS devices having noble material films

    DOE Patents [OSTI]

    Hankins, Matthew G. (Albuquerque, NM)

    2009-10-06T23:59:59.000Z

    Etchant solutions comprising a redox buffer can be used during the release etch step to reduce damage to the structural layers of a MEMS device that has noble material films. A preferred redox buffer comprises a soluble thiophosphoric acid, ester, or salt that maintains the electrochemical potential of the etchant solution at a level that prevents oxidation of the structural material. Therefore, the redox buffer preferentially oxidizes in place of the structural material. The sacrificial redox buffer thereby protects the exposed structural layers while permitting the dissolution of sacrificial oxide layers during the release etch.

  14. Cooling Flows or Heating Flows?

    E-Print Network [OSTI]

    James Binney

    2003-10-08T23:59:59.000Z

    It is now clear that AGN heat cooling flows, largely by driving winds. The winds may contain a relativistic component that generates powerful synchrotron radiation, but it is not clear that all winds do so. The spatial and temporal stability of the AGN/cooling flow interaction are discussed. Collimation of the winds probably provides spatial stability. Temporal stability may be possible only for black holes with masses above a critical value. Both the failure of cooling flows to have adiabatic cores and the existence of X-ray cavities confirm the importance of collimated outflows. I quantify the scale of the convective flow that the AGN Hydra would need to drive if it balanced radiative inward flow by outward flow parallel to the jets. At least in Virgo any such flow must be confined to r<~20 kpc. Hydrodynamical simulations suggest that AGN outbursts cannot last longer than ~25 Myr. Data for four clusters with well studied X-ray cavities suggests that heating associated with cavity formation approximately balances radiative cooling. The role of cosmic infall and the mechanism of filament formation are briefly touched on.

  15. Unveiling Surface Redox Charge Storage of Interacting Two-Dimensional Hetero-Nanosheets in Hierarchical Architectures

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Mahmood, Qasim; Bak, Seong-Min; Kim, Min G.; Yun, Sol; Yang, Xiao-Qing; Shin, Hyeon S.; Kim, Woo S.; Braun, Paul V.; Park, Ho S.

    2015-04-08T23:59:59.000Z

    Two-dimensional (2D) heteronanosheets are currently the focus of intense study due to the unique properties that emerge from the interplay between two low-dimensional nanomaterials with different properties. However, the properties and new phenomena based on the two 2D heteronanosheets interacting in a 3D hierarchical architecture have yet to be explored. Here, we unveil the surface redox charge storage mechanism of surface-exposed WS2 nanosheets assembled in a 3D hierarchical heterostructure using in situ synchrotron X-ray absorption and Raman spectroscopic methods. The surface dominating redox charge storage of WS2 is manifested in a highly reversible and ultrafast capacitive fashion due to themore »interaction of heteronanosheets and the 3D connectivity of the hierarchical structure. In contrast, compositionally identical 2D WS2 structures fail to provide a fast and high capacitance with different modes of lattice vibration. The distinctive surface capacitive behavior of 3D hierarchically structured heteronanosheets is associated with rapid proton accommodation into the in-plane W–S lattice (with the softening of the E2g bands), the reversible redox transition of the surface-exposed intralayers residing in the electrochemically active 1T phase of WS2 (with the reversible change in the interatomic distance and peak intensity of W–W bonds), and the change in the oxidation state during the proton insertion/deinsertion process. This proposed mechanism agrees with the dramatic improvement in the capacitive performance of the two heteronanosheets coupled in the hierarchical structure.« less

  16. Received 11 Jan 2013 | Accepted 29 Apr 2013 | Published 13 Jun 2013 Cyclic electron flow is redox-controlled

    E-Print Network [OSTI]

    . Correspondence and requests for materials should be addressed to F.R. (email: Fabrice.Rappaport@ibpc.fr). NATURE Publishers Limited. All rights reserved. #12;T he injection of energy into the biosphere relies-containing stroma lamellae, thereby balancing the excitonic flux between the two photosystems10. In the unicellular

  17. Some Lessons Learned from 20 Years in RedOx Flow Battery R&d | Department

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn'tOriginEducationVideo »UsageSecretaryVideos Solid-State Lighting Videos On thisEnergy Moreof

  18. Inner-Sphere Electron-Transfer Single Iodide Mechanism for Dye Regeneration in Dye-Sensitized Solar Cells

    E-Print Network [OSTI]

    Goddard III, William A.

    the regeneration of the oxidized dye in dye-sensitized solar cells, the redox couple of I- /I3 - reduces the photo dye- sensitized solar cell (DSSC) in 1991,1 DSSCs have been considered as promising alternativesInner-Sphere Electron-Transfer Single Iodide Mechanism for Dye Regeneration in Dye-Sensitized Solar

  19. Preserving the Volume of Fluid Using Multi-phase Flow Approach Roman Durikovic

    E-Print Network [OSTI]

    Durikovic, Roman

    complex behaviors. We often see rising bubbles or flow of muddy water, such flows involve sev- eral fluids volume when the fluid passes through a donor cell to an acceptor cell. The VOF method was improved

  20. BIOENERGY AND BIOFUELS Performance of a pilot-scale continuous flow microbial

    E-Print Network [OSTI]

    BIOENERGY AND BIOFUELS Performance of a pilot-scale continuous flow microbial electrolysis cell fed performance. Keywords Biohydrogen . Biomethane . Bioelectricity. Microbial electrolysis cell . Bioenergy

  1. Influence of pH and Redox Conditions on Copper Leaching

    SciTech Connect (OSTI)

    Kavanaugh, Rathi; Al-Abed, Souhail R.; Purandare, Jaydeep; Allen, Derrick

    2004-03-31T23:59:59.000Z

    The Toxicity Characteristic Leaching Procedure (TCLP) is a regulatory leach test in the RCRA programs. It was developed to determine the leaching potential of landfilled waste in order to assess the hazards associated with the leachates. The test was developed to study concentration of hazardous materials in leachates, under a mismanagement scenario, when they are co-disposed with municipal waste. The test uses leaching of waste at either of two acidic pH values i.e., 2.8 and 4.93. While low pH leachant can extract many metals, some metals soluble at higher pH values are either underestimated or totally unaccounted for. The method also has limitations for application to different waste matrices. The procedure does not take into account the effect of redox conditions on leaching. Leaching studies are, therefore, being conducted to determine the effect of combinations of Eh and pH on the leaching potential of mineral and organic wastes. The goal of this study is to propose alternate methods applicable for a variety of waste matrices. The presentation will discuss the effects of combinations of pH and redox conditions on the leaching behavior of copper from a mineral processing waste.

  2. Redox Active Layer-by-Layer Structures containing MnO2 Nanoparticles

    SciTech Connect (OSTI)

    Bazito, Fernanda; O'Brien, Robert; Buttry, Daniel A.

    2005-02-01T23:59:59.000Z

    Nanoscale materials provide unique properties that will enable new technologies and enhance older ones. One area of intense activity in which nanoscale materials are being used is in the development of new functional materials for battery applications. This effort promises superior materials with properties that circumvent many of the problems associated with traditional battery materials. Previously we have worked on several approaches for using nanoscale materials for application as cathode materials in rechargeable Li batteries. Our recent work has focused on synthesizing MnO2 nanoparticles and using these in layer-by-layer (LbL) structures to probe the redox properties of the nanoparticles. We show that the aqueous colloidal nanoparticles produced by butanol reduction of tetramethylammonium permanganate can be trapped in thin films using a layer-by-layer deposition approach, and that these films are both redox active and exhibit kinetically facile electrochemical responses. We show cyclic voltammetry of MnO2 colloidal nanoparticles entrapped in a LbL thin film at an ITO electrode surface using poly(diallyldimethylammonium chloride) (PDDA). CV experiments demonstrate that Li+ insertion accompanies Mn(IV) reduction in LiClO4 supporting electrolytes, and that reduction is hindered in supporting electrolytes containing only tetrabutylammonium cations. We also show that electron propagation through multilayer films is facile, suggesting that electrons percolate through the films via electron exchange between nanoparticles.

  3. Molybdenum in Nuclear Waste Glasses -Incorporation and Redox state R.J. Short, R.J. Hand, N.C. Hyatt,

    E-Print Network [OSTI]

    Sheffield, University of

    Molybdenum in Nuclear Waste Glasses - Incorporation and Redox state R.J. Short, R.J. Hand, N form in simulated high level nuclear waste (HLW) glass melts have been studied. It was found less attention has been paid to the effects of redox on nuclear waste glasses. One particular element

  4. Micro free-flow isoelectric focusing

    E-Print Network [OSTI]

    Albrecht, Jacob William

    2008-01-01T23:59:59.000Z

    To unravel the complexity of cellular systems, protein prefractionation tools can be used to reduce cell lysate complexity and increase assay sensitivity. Rapid free flow isoelectric focusing (FF-IEF) is achieved in a ...

  5. Development of the in vivo flow cytometer

    E-Print Network [OSTI]

    Novak, John P. (John Peter), 1957-

    2004-01-01T23:59:59.000Z

    An in vivo flow cytometer has been developed that allows the real-time detection and quantification of circulating cells containing fluorescent proteins or labeled with fluorochrome molecules in live animals, without the ...

  6. Neutrino Factory Mercury Flow Loop

    E-Print Network [OSTI]

    McDonald, Kirk

    ­ Could require double containment of mercury ­ Chase will certainly have a drain back into hot cell Decay 2010 #12;Hg Flow Overflow · Minimize pressure drops through piping Overflow Mercury Drain drops Gravity Drain Beam Dumptransitioning to 1 cm nozzle · Actual NF Hg inventory may reach SNS Gravity Drain

  7. A Semiconductor Microlaser for Intracavity Flow Cytometry

    SciTech Connect (OSTI)

    Akhil, O.; Copeland, G.C.; Dunne, J.L.; Gourley, P.L.; Hendricks, J.K.; McDonald, A.E.

    1999-01-20T23:59:59.000Z

    Semiconductor microlasers are attractive components for micro-analysis systems because of their ability to emit coherent intense light from a small aperture. By using a surface-emitting semiconductor geometry, we were able to incorporate fluid flow inside a laser microcavity for the first time. This confers significant advantages for high throughput screening of cells, particulates and fluid analytes in a sensitive microdevice. In this paper we discuss the intracavity microfluidics and present preliminary results with flowing blood and brain cells.

  8. Miniaturized flow injection analysis system

    DOE Patents [OSTI]

    Folta, James A. (Livermore, CA)

    1997-01-01T23:59:59.000Z

    A chemical analysis technique known as flow injection analysis, wherein small quantities of chemical reagents and sample are intermixed and reacted within a capillary flow system and the reaction products are detected optically, electrochemically, or by other means. A highly miniaturized version of a flow injection analysis system has been fabricated utilizing microfabrication techniques common to the microelectronics industry. The microflow system uses flow capillaries formed by etching microchannels in a silicon or glass wafer followed by bonding to another wafer, commercially available microvalves bonded directly to the microflow channels, and an optical absorption detector cell formed near the capillary outlet, with light being both delivered and collected with fiber optics. The microflow system is designed mainly for analysis of liquids and currently measures 38.times.25.times.3 mm, but can be designed for gas analysis and be substantially smaller in construction.

  9. Enhanced expression of cyclins and cyclin-dependent kinases in aniline-induced cell proliferation in rat spleen

    SciTech Connect (OSTI)

    Wang Jianling; Wang Gangduo; Ma Huaxian; Khan, M. Firoze, E-mail: mfkhan@utmb.edu

    2011-01-15T23:59:59.000Z

    Aniline exposure is associated with toxicity to the spleen leading to splenomegaly, hyperplasia, fibrosis and a variety of sarcomas of the spleen on chronic exposure. In earlier studies, we have shown that aniline exposure leads to iron overload, oxidative stress and activation of redox-sensitive transcription factors, which could regulate various genes leading to a tumorigenic response in the spleen. However, molecular mechanisms leading to aniline-induced cellular proliferation in the spleen remain largely unknown. This study was, therefore, undertaken on the regulation of G1 phase cell cycle proteins (cyclins), expression of cyclin-dependent kinases (CDKs), phosphorylation of retinoblastoma protein (pRB) and cell proliferation in the spleen, in an experimental condition preceding a tumorigenic response. Male SD rats were treated with aniline (0.5 mmol/kg/day via drinking water) for 30 days (controls received drinking water only), and splenocyte proliferation, protein expression of G1 phase cyclins, CDKs and pRB were measured. Aniline treatment resulted in significant increases in splenocyte proliferation, based on cell counts, cell proliferation markers including proliferating cell nuclear antigen (PCNA), nuclear Ki67 protein (Ki67) and minichromosome maintenance (MCM), MTT assay and flow cytometric analysis. Western blot analysis of splenocyte proteins from aniline-treated rats showed significantly increased expression of cyclins D1, D2, D3 and E, as compared to the controls. Similarly, real-time PCR analysis showed significantly increased mRNA expression for cyclins D1, D2, D3 and E in the spleens of aniline-treated rats. The overexpression of these cyclins was associated with increases in the expression of CDK4, CDK6, CDK2 as well as phosphorylation of pRB protein. Our data suggest that increased expression of cyclins, CDKs and phosphorylation of pRB protein could be critical in cell proliferation, and may contribute to aniline-induced tumorigenic response in the spleen.

  10. 1246 J. Am. Chem. SOC. 1995, 117, 1246-1257 RNA Aptamers That Bind Flavin and Nicotinamide Redox

    E-Print Network [OSTI]

    Heller, Eric

    that specifically bind riboflavin (Rb) and P-nicotinamide mononucleotide (NMN) have been isolated by in vitro to oxidized riboflavin (& = 1-5 pM). DNA versions of the consensus sequence also bind, but with weaker structural analog of riboflavin. In contrast to the lack of redox specificity of the riboflavin aptamers

  11. DOI: 10.1002/ejic.201000555 Flexible and Redox-Active Coordination Polymer: Control of the Network

    E-Print Network [OSTI]

    Paik Suh, Myunghyun

    *[a] Keywords: Coordination polymers / Flexible networks / Macrocyles / Palladium / Nickel The coordination[3a] as well as in the fourfold interpenetrating dia- mondoid network[11] by the reaction of organicFULL PAPER DOI: 10.1002/ejic.201000555 Flexible and Redox-Active Coordination Polymer: Control

  12. The development of a rod-coil redox polymer composed of biphenyl esters and poly (4-vinylpyridine)

    E-Print Network [OSTI]

    DeCormier, Amy Urbanowicz

    2001-01-01T23:59:59.000Z

    A rod-coil polymer was successfully synthesized to provide a backbone structure from which a redox polymer was produced. The rod was composed of biphenyl esters and the coil was composed of poly (4-vinylpyridine). The coil was produced by anionic...

  13. Mobilisation of arsenic from bauxite residue (red mud) affected soils: Effect of pH and redox conditions

    E-Print Network [OSTI]

    Burke, Ian

    ). Typically, it comprises residual iron oxides, quartz, sodium aluminosilicates, titanium dioxide, calciumMobilisation of arsenic from bauxite residue (red mud) affected soils: Effect of pH and redox elements, including arsenic. Aerobic and anaer- obic batch experiments were prepared using soils from near

  14. Discovery of agglutinated benthic foraminifera in Devonian black shales and their relevance for the redox state of ancient seas

    E-Print Network [OSTI]

    Polly, David

    Discovery of agglutinated benthic foraminifera in Devonian black shales and their relevance Received in revised form 4 October 2008 Accepted 31 October 2008 Keywords: Black shale Redox Devonian. The discovery that they occur widely in Late Devonian black shales has a bearing on the boundary conditions

  15. Toll-like receptor 4 signaling on CD4+ T cells plays a regulatory role in inflammatory bowel disease

    E-Print Network [OSTI]

    Law, Jason Kumhung

    2010-01-01T23:59:59.000Z

    through a 100-µm cell strainer, and the flow throughcollected using a 40-µm cell strainer. Finally, the IELs and

  16. Sampling, preservation, and analytical methods research plan - liquid redox sulfur recovery technologies: Stretford process. Topical report

    SciTech Connect (OSTI)

    Trofe, T.W.

    1986-11-01T23:59:59.000Z

    GRI has developed a sampling, preservation, and analytical (SPandA) methods research plan for developing and validating analytical methodologies for liquid redox sulfur recovery processes (e.g., Stretford process). The document describes the technical approach which will be used to direct research activities to develop SPandA methodologies to analyze gaseous, aqueous, and solid process streams from the Stretford sulfur recovery process. The primary emphasis is on developing and validating methodologies for analyzing vanadium (IV) and vanadium (V), anthraquinone disulphonic acids (ADA), polysulfide-sulfur, sulfide-sulfur, thiosulfate, sulfate, thiocyanate, total soluble sulfur, alkalinity, pH, total dissolved solids, total suspended solids, and dissolved oxygen in aqueous process streams. The document includes descriptions of the process streams and chemical species, selection of candidate analytical methods, and technical approach for methods development and validation.

  17. Solar Thermochemical Fuels Production: Solar Fuels via Partial Redox Cycles with Heat Recovery

    SciTech Connect (OSTI)

    None

    2011-12-19T23:59:59.000Z

    HEATS Project: The University of Minnesota is developing a solar thermochemical reactor that will efficiently produce fuel from sunlight, using solar energy to produce heat to break chemical bonds. The University of Minnesota is envisioning producing the fuel by using partial redox cycles and ceria-based reactive materials. The team will achieve unprecedented solar-to-fuel conversion efficiencies of more than 10% (where current state-of-the-art efficiency is 1%) by combined efforts and innovations in material development, and reactor design with effective heat recovery mechanisms and demonstration. This new technology will allow for the effective use of vast domestic solar resources to produce precursors to synthetic fuels that could replace gasoline.

  18. Redox Control For Hanford HLW Feeds VSL-12R2530-1, REV 0

    SciTech Connect (OSTI)

    Kruger, A. A. [Department of Energy, Office of River Protection, Richland, Washington (United States); Matlack, Keith S. [The Catholic University of America, Washington, DC (United States); Pegg, Ian L. [The Catholic University of America, Washington, DC (United States); Kot, Wing K. [The Catholic University of America, Washington, DC (United States); Joseph, Innocent [The Catholic University of America, Washington, DC (United States)

    2012-12-13T23:59:59.000Z

    The principal objectives of this work were to investigate the effects of processing simulated Hanford HLW at the estimated maximum concentrations of nitrates and oxalates and to identify strategies to mitigate any processing issues resulting from high concentrations of nitrates and oxalates. This report provides results for a series of tests that were performed on the DM10 melter system with simulated C-106/AY-102 HLW. The tests employed simulated HLW feeds containing variable amounts of nitrates and waste organic compounds corresponding to maximum concentrations proj ected for Hanford HLW streams in order to determine their effects on glass production rate, processing characteristics, glass redox conditions, melt pool foaming, and the tendency to form secondary phases. Such melter tests provide information on key process factors such as feed processing behavior, dynamic effects during processing, processing rates, off-gas amounts and compositions, foaming control, etc., that cannot be reliably obtained from crucible melts.

  19. Micelle formation and surface activity of functional redox relays: viologens substituted by a long alkyl chain

    SciTech Connect (OSTI)

    Krieg, M.; Pileni, M.P.; Braun, A.M.; Gratzel, M.

    1981-09-01T23:59:59.000Z

    Viologens are receiving increasing attention from 2 major domains. First, photo- and electroreproductive processes are being developed which exploit the pronounced chromophore effect associated with the one-electron reduction of the viologens: the 2+ state is practically colorless, while the 1+ state has an intense color. However, the most prominent impact in viologen-related research arises from their use as mediators, sometimes referred to as electron relays, in the photionduced generation of hydrogen from water. Photobiologists had discovered earlier that methyl viologen in chloroplast suspensions is suited to act as a Hill reagent which can be coupled with hydrogenase to yield H/sub 2/ under illumination. More recently, in vitro systems have been developed in which synthetic dyes replace the chloroplasts as redox sensitizers. These have been shown to be remarkably effective in H/sub 2/ production. The surfactant and micellar properties of a series of potent candidates, i.e., long-chain-substituted viologens are investigated.

  20. Electrocatalytic hydrogenation using precious metal microparticles in redox-active polymer films

    SciTech Connect (OSTI)

    Coche, L.; Ehui, B.; Limosin, D.; Moutet, J.C. (Univ. Joseph Fourier, Grenoble (France))

    1990-11-09T23:59:59.000Z

    Glassy carbon felt electrodes have been modified by electrodeposition of poly(pyrrole-viologen) films (derived from N,N{prime}-dialkyl-4,4{prime}-bipyridinium salts), followed by electroprecipitation of precious metal (Pt, Pd, Rh, or Ru) microparticles. The resulting electrodes have been proved to be active for the electrocatalytic hydrogenation of conjugated enones (2-cyclohexen-1-one, cryptone, carvone, isophorone), styrene, and benzonitrile in aqueous media (pH 1). Despite low loadings of metal catalysts, high electric and products yields and a long term stability of these cathodes have been observed. The influence of the metal loading and the polymer structure on the catalytic efficiency as well as the selectivity obtained according to the metal catalyst used have been studied. Comparison with results previously reported for other catalytic cathodes like Pt/Pt, Pd/C, or Raney nickel electrodes proves the high efficiency of these metal microparticles within redox polymer film based electrodes.

  1. The complementary redox properties of viologens and pyromellitimides: A new class of organic conductors

    SciTech Connect (OSTI)

    Buchwalter, S.L.; Iyengar, R.; Viehbeck, A.; O'Toole, T.R. (Thomas J. Watson Research Center, Yorktown Heights, NY (USA))

    1991-01-02T23:59:59.000Z

    Organic charge-transfer (CT) salts have been of interest for some years, especially since the discovery of the metallic conductivity of the TTF-TCNQ salt. The authors have begun an investigation of the charge-transfer chemistry of viologens and pyromellitimides, based on their complementary redox properties, with the intention of proceeding from intermolecular examples to intramolecular CT salts and finally to examples in which the viologens and pyromellitimides are incorporated in a polymer. They report progress in the first two stages of this investigation, including isolation of a new, highly conductive intermolecular CT salt and electrochemical characterization of a covalently linked viologen/pyromellitimide. These studies point to an interesting new class of organic solid-state materials.

  2. Miniature fuel-cell system complete with on-demand fuel and oxidant supply

    E-Print Network [OSTI]

    Hur, JI; Kim, C-J

    2015-01-01T23:59:59.000Z

    scale direct methanol fuel cell development,” Energy, vol.flow-based microfluidic fuel cell," J. Am. Chem. Soc. , vol.electrolyte membrane fuel cell design," J. Power Sources,

  3. Two-phase flow and transport Volume 3, Part 3, pp 337347

    E-Print Network [OSTI]

    Two-phase flow and transport C.-Y. Wang Volume 3, Part 3, pp 337­347 in Handbook of Fuel Cells cells include hydrogen or refor- mate/air PEM fuel cells (PEMFC) and PEM-based direct methanol fuel fuel cells. The two-phase flow and transport through the porous structure of GDL, which underlies

  4. Microfluidic Flow-Flash: Method for Investigating Protein Dynamics

    E-Print Network [OSTI]

    Kenis, Paul J. A.

    Microfluidic Flow-Flash: Method for Investigating Protein Dynamics Michael W. Toepke, Scott H Institute, Troy, New York 12180 We report a new method, microfluidic flow-flash, for measuring protein reaction kinetics. The method couples a microscope imaging detection system with a microfluidic flow cell

  5. Amphiphilic mediated sample preparation for micro-flow cytometry

    DOE Patents [OSTI]

    Clague, David S. (Livermore, CA); Wheeler, Elizabeth K. (Livermore, CA); Lee, Abraham P. (Irvine, CA)

    2006-07-25T23:59:59.000Z

    A flow cytometer includes a flow cell for detecting the sample, an oil phase in the flow cell, a water phase in the flow cell, an oil-water interface between the oil phase and the water phase, a detector for detecting the sample at the oil-water interface, and a hydrophobic unit operatively connected to the sample. The hydrophobic unit is attached to the sample. The sample and the hydrophobic unit are placed in an oil and water combination. The sample is detected at the interface between the oil phase and the water phase.

  6. Amphiphilic mediated sample preparation for micro-flow cytometry

    DOE Patents [OSTI]

    Clague, David S. (Livermore, CA); Wheeler, Elizabeth K. (Livermore, CA); Lee, Abraham P. (Irvine, CA)

    2009-03-17T23:59:59.000Z

    A flow cytometer includes a flow cell for detecting the sample, an oil phase in the flow cell, a water phase in the flow cell, an oil-water interface between the oil phase and the water phase, a detector for detecting the sample at the oil-water interface, and a hydrophobic unit operatively connected to the sample. The hydrophobic unit is attached to the sample. The sample and the hydrophobic unit are placed in an oil and water combination. The sample is detected at the interface between the oil phase and the water phase.

  7. NEUTROPHILS INFLUENCE MELANOMA ADHESION AND MIGRATION UNDER FLOW CONDITIONS

    E-Print Network [OSTI]

    Dong, Cheng

    NEUTROPHILS INFLUENCE MELANOMA ADHESION AND MIGRATION UNDER FLOW CONDITIONS Margaret J. SLATTERY State University, University Park, PA, USA We have studied human melanoma cell (C8161) adhesion to be very low on these melanoma cells. As a result, C8161 trans- endothelial migration under a flow

  8. GEOC R Lee Penn Sunday, March 25, 2012 12 -Biogeochemical transformation of Fe-and Mn-along a redox gradient: Implications for carbon sequestration

    E-Print Network [OSTI]

    Sparks, Donald L.

    a redox gradient: Implications for carbon sequestration within the Christina River Basin Critical Zone States Organic carbon (C)-mineral complexation mechanism is crucial in C sequestration. It is a function

  9. The Redox Domain of the Yap1p Transcription Factor Contains Two Disulfide Matthew J. Wood, Erika C. Andrade, and Gisela Storz*

    E-Print Network [OSTI]

    Storz, Gisela

    separate cysteine-containing peptides of Yap1p. These peptides are separated by 250 amino acids to only serve as antioxidants, such as Cys-2 Prxs and Gpx3p, now appear to be redox regulated and play

  10. A novel redox-based switch: LMW-PTP oxidation enhances Grb2 binding and leads to ERK activation

    SciTech Connect (OSTI)

    Giannoni, Elisa [Department of Biochemical Sciences, University of Florence, Viale Morgagni 50, 50134 Florence (Italy); Raugei, Giovanni [Department of Biochemical Sciences, University of Florence, Viale Morgagni 50, 50134 Florence (Italy); Center of Excellence for Scientific Research DENOTHE, Viale Morgagni 44, 50134 Florence (Italy); Chiarugi, Paola [Department of Biochemical Sciences, University of Florence, Viale Morgagni 50, 50134 Florence (Italy) and Center of Excellence for Scientific Research DENOTHE, Viale Morgagni 44, 50134 Florence (Italy)]. E-mail: paola.chiarugi@unifi.it; Ramponi, Giampietro [Department of Biochemical Sciences, University of Florence, Viale Morgagni 50, 50134 Florence (Italy); Center of Excellence for Scientific Research DENOTHE, Viale Morgagni 44, 50134 Florence (Italy)

    2006-09-22T23:59:59.000Z

    Low molecular weight-PTP has been reported as a redox-sensitive protein during both platelet-derived growth factor and integrin signalling. In response to oxidation the phosphatase undergoes a reversible inactivation, which in turn leads to the increase in tyrosine phosphorylation of its substrates and the properly executed anchorage-dependent proliferation program. Here, we report that an exogenous oxidative stress enhances LMW-PTP tyrosine phosphorylation, through oxidation/inactivation of the enzyme, thus preventing its auto-dephosphorylation activity. In particular, we observed a selective hyper-phosphorylation of Tyr132, that acts as a docking site for the adaptor protein Grb2. The redox-dependent enhancement of Grb2 recruitment to LMW-PTP ultimately leads to an improvement of ERK activation, likely triggering a prosurvival signal against the oxidant environment.

  11. Low volume flow meter

    DOE Patents [OSTI]

    Meixler, Lewis D. (East Windsor, NJ)

    1993-01-01T23:59:59.000Z

    The low flow monitor provides a means for determining if a fluid flow meets a minimum threshold level of flow. The low flow monitor operates with a minimum of intrusion by the flow detection device into the flow. The electrical portion of the monitor is externally located with respect to the fluid stream which allows for repairs to the monitor without disrupting the flow. The electronics provide for the adjustment of the threshold level to meet the required conditions. The apparatus can be modified to provide an upper limit to the flow monitor by providing for a parallel electronic circuit which provides for a bracketing of the desired flow rate.

  12. Ichno-sedimentological record of short-term climate-controlled redox events and cycles in organic-rich strata

    SciTech Connect (OSTI)

    Savrda, C.E. (Auburn Univ., AL (USA)); Bottjher, D.J. (Univ. of Southern California, Los Angeles (USA)); Ozalas, K. (Auburn Univ., AL (USA))

    1990-05-01T23:59:59.000Z

    Reduced rates of biochemical degradation of organic matter in oxygen-depleted marine settings generally result in the accumulation of laminated strata with high hydrocarbon source potential. Periods of improved oxygenation, during which the quantity and quality of organic matter are effectively reduced, are reflected by interbedded bioturbated intervals. Such benthic redox excursions may reflect variable paleooceanographic responses to climatic events or cycles. The potential role of climate in the short-term modulation of source rock potential is exemplified by bioturbated intervals within three predominantly laminated organic-rich units. The Jurassic Posidonia Shale (Germany) contains bioturbated beds whose ichnologic characteristics reflect a spectrum from short, low-magnitude redox events to longer episodes of greater magnitude. The character and distribution of these event beds appear to be controlled by sea level mediated variations in the frequency and intensity of storm-induced basin turnover. Bioturbated beds of the Upper Cretaceous Niobrara Formation (Colorado) are characterized by four oxygen-related ichnocoenoses, the distribution of which reflects cyclic variations in redox conditions. Relationships between paleooxygenation and organic-carbon and carbonate contents, and estimated cycle periodicities, suggest that redox variations were controlled by wet-dry climatic cycles modulated by the Milankovitch cycle of axial precession. Bioturbated beds within slope and basinal facies of the Miocene Monterey Formation (California) are variable in character, reflecting differences in duration and magnitude of associated oxygenation episodes, and may be in response to short-term variations in wind-stress-induced upwelling and/or ice-volume-controlled eustatic sea level changes.

  13. Photoelectrochemical investigation of a poly(ethylene oxide) cell

    SciTech Connect (OSTI)

    Sammells, A.F.; Ang, G.P.

    1984-03-01T23:59:59.000Z

    The photoelectrochemical properties of cells based on the solid polymer electrolyte (SPE) poly(ethylene oxide)/NaSCN with Na2S/S as a redox species are investigated experimentally. The preparation of the SPE is described in detail. Current/voltage curves or voltage/time are shown for cells using p-InP/SPE/conducting-glass, n-GaAs/SPE/conducting-glass, and p-InP/SPE/n-CdS structures. It is concluded that practical cells based on SPE of this type will require increases in the ionic conductivity of poly(ethylene oxide). 13 references.

  14. Corrosion, Passivation, and the Effect of Water Addition on an n-GaAs(100)/Methanol Photoelectrochemical Cell

    E-Print Network [OSTI]

    Richmond, Geraldine L.

    Corrosion, Passivation, and the Effect of Water Addition on an n-GaAs(100)/Methanol of corrosion of the cell on the PL-V profile is examined in detail. It is found that the inclusion of the redox couple gives some protection from corrosion, but the addition of a small amount of water

  15. Waveguide detection of right-angle-scattered light in flow cytometry

    DOE Patents [OSTI]

    Mariella, Jr., Raymond P. (Danville, CA)

    2000-01-01T23:59:59.000Z

    A transparent flow cell is used as an index-guided optical waveguide. A detector for the flow cell but not the liquid stream detects the Right-Angle-Scattered (RAS) Light exiting from one end of the flow cell. The detector(s) could view the trapped RAS light from the flow cell either directly or through intermediate optical light guides. If the light exits one end of the flow cell, then the other end of the flow cell can be given a high-reflectivity coating to approximately double the amount of light collected. This system is more robust in its alignment than the traditional flow cytometry systems which use imaging optics, such as microscope objectives.

  16. Redox-Dependent Solubility of Technetium in Low Activity Waste Glass

    SciTech Connect (OSTI)

    Soderquist, Chuck Z.; Schweiger, Michael J.; Kim, Dong-Sang; Lukens, Wayne W.; Mccloy, John S.

    2014-03-01T23:59:59.000Z

    The solubility of technetium was measured in a Hanford low activity waste glass simulant. The simulant glass was melted, quenched and pulverized to make a stock of powdered glass. A series of glass samples were prepared using the powdered glass and varying amounts of solid potassium pertechnetate. Samples were melted at 1000°C in sealed fused quartz ampoules. After cooling, the bulk glass and the salt phase above the glass (when present) were sampled for physical and chemical characterization. Technetium was found in the bulk glass up to 2000 ppm (using the glass as prepared) and 3000 ppm (using slightly reducing conditions). The chemical form of technetium obtained by x-ray absorption near edge spectroscopy can be mainly assigned to isolated Tc(IV), with a minority of Tc(VII) in some glasses and TcO2 in two glasses. The concentration and speciation of technetium depends on glass redox and amount of technetium added. Solid crystals of pertechnetate salts were found in the salt cake layer that formed at the top of some glasses during the melt.

  17. JUPITER-II Molten Salt Flibe Research: An Update On Tritium, Mobilization and Redox Chemistry Experiments

    SciTech Connect (OSTI)

    D.A. Petti; D. A. Petti; G. R. Smolik; Michael F. Simpson; John P. Sharpe; R. A. Anderl; S. Fukada; Y. Hatano; Masanori Hara; Y. Oya; T. Terai; D.-K. Sze; S. Tanaka

    2005-05-01T23:59:59.000Z

    The second Japan/US Program on Irradiation Tests for Fusion Research (JUPITER-II) began on April 1, 2001. Part of the collaborative research centers on studies of the molten salt 2LiF2–BeF2 (also known as Flibe) for fusion applications. Flibe has been proposed as a self-cooled breeder in both magnetic and inertial fusion power plant designs over the last 25 years. The key feasibility issues associated with the use of Flibe are the corrosion of structural material by the molten salt, tritium behavior and control in the molten salt blanket system, and safe handling practices and releases from Flibe during an accidental spill. These issues are all being addressed under the JUPITER-II program at the Idaho National Laboratory in the Safety and Tritium Applied Research (STAR) facility. In this paper, we review the program to date in the area of tritium/deuterium behavior, Flibe mobilization under accident conditions and testing of Be as a redox agent to control corrosion. Future activities planned through the end of the collaboration are also presented.

  18. Chemiluminescence Excitation in the Redox Reactions of MetalCarbonyls and Their Derivatives with Xenon Difluoride

    SciTech Connect (OSTI)

    Bulgakov, R.G.; Kuleshov, S.P.; Tolstikov, G.A; Yakoulev, V.N.

    1985-11-01T23:59:59.000Z

    The authors use gas-liquid chromatography, volumetry, elemental analysis, and UV, visible, and IR absorption spectroscopy to study the oxidation of XeF/sub 2/ by carbonyls of group VI-VIII metals Mo(CO)/sub 6/, (C/sub 6/H/sub 5/CH/sub 3/) Mo(CO)/sub 3/, W(CO)/sub 6/, Mn/sub 2/(CO)/sub 10/, C/sub 5/H/sub 5/Mn(CO)/sub 3/, Fe(CO)/sub 5/, Fe/sub 2/(CO)/sub 9/, and (acac) Rh(CO)/sub 2/. The reactions are accompanied by change in solution color, the release of gaseous Xe and CO, and the formation of fluoro derivatives of metal carbonyls and metal fluorides. Chemiluminescence is excited in the overall process of the consecutive redox replacement of CO groups in the metal carbonyl by F. The only case of the absence of chemiluminescence in the case of the oxidation of Mn/sub 2/(CO)/sub 10/ is related to the existence of an Mn-Mn bond in this metal carbonyl. Mn/sub 2/(CO)/sub 10/ also efficiently quenches the background chemiluminescence due to the reaction of XeF/sub 2/ with CH/sub 2/Cl/sub 2/ and toluene.

  19. Transitions from near-surface to interior redox upon lithiation in conversion electrode materials

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    He, Kai; Xin, Huolin L.; Zhao, Kejie; Yu, Xiqian; Norlund, Dennis; Weng, Tsu-Chien; Li, Jing; Jiang, Yi; Cadigan, Christopher A.; Richards, Ryan M.; et al

    2015-02-11T23:59:59.000Z

    Nanoparticle electrodes in lithium-ion batteries have both near-surface and interior contributions to their redox capacity, each with distinct rate capabilities. Using combined electron microscopy, synchrotron X-ray methods and ab initio calculations, we have investigated the lithiation pathways that occur in NiO electrodes. We find that the near-surface electroactive (Ni²??Ni?) sites saturated very quickly, and then encounter unexpected difficulty in propagating the phase transition into the electrode (referred to as a “shrinking-core” mode). However, the interior capacity for Ni²??Ni? can be accessed efficiently following the nucleation of lithiation “fingers” which propagate into the sample bulk, but only after a certain incubationmore »time. Our microstructural observations of the transition from a slow shrinking-core mode to a faster lithiation finger mode corroborate with synchrotron characterization of large-format batteries, and can be rationalized by stress effects on transport at high-rate discharge. The finite incubation time of the lithiation fingers sets the intrinsic limitation for the rate capability (and thus the power) of NiO for electrochemical energy storage devices. The present work unravels the link between the nanoscale reaction pathways and the C-rate-dependent capacity loss, and provides guidance for the further design of battery materials that favors high C-rate charging.« less

  20. Transitions from near-surface to interior redox upon lithiation in conversion electrode materials

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    He, Kai [Brookhaven National Lab. (BNL), Upton, NY (United States); Xin, Huolin L. [Brookhaven National Lab. (BNL), Upton, NY (United States); Zhao, Kejie [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States); Yu, Xiqian [Brookhaven National Lab. (BNL), Upton, NY (United States); Norlund, Dennis [SLAC National Accelerator Lab., Menlo Park, CA (United States); Weng, Tsu-Chien [SLAC National Accelerator Lab., Menlo Park, CA (United States); Li, Jing [Brookhaven National Lab. (BNL), Upton, NY (United States); Stony Brook Univ., Stony Brook, NY (United States); Jiang, Yi [Cornell Univ., Ithaca, NY (United States); Cadigan, Christopher A. [Colorado School of Mines, Golden, CO (United States); Richards, Ryan M. [Colorado School of Mines, Golden, CO (United States); Doeff, Marca M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Yang, Xiao-Qing [Brookhaven National Lab. (BNL), Upton, NY (United States); Stach, Eric A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Li, Ju [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States); Lin, Feng [Colorado School of Mines, Golden, CO (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Su, Dong [Brookhaven National Lab. (BNL), Upton, NY (United States); Stony Brook Univ., Stony Brook, NY (United States)

    2015-02-11T23:59:59.000Z

    Nanoparticle electrodes in lithium-ion batteries have both near-surface and interior contributions to their redox capacity, each with distinct rate capabilities. Using combined electron microscopy, synchrotron X-ray methods and ab initio calculations, we have investigated the lithiation pathways that occur in NiO electrodes. We find that the near-surface electroactive (Ni²??Ni?) sites saturated very quickly, and then encounter unexpected difficulty in propagating the phase transition into the electrode (referred to as a “shrinking-core” mode). However, the interior capacity for Ni²??Ni? can be accessed efficiently following the nucleation of lithiation “fingers” which propagate into the sample bulk, but only after a certain incubation time. Our microstructural observations of the transition from a slow shrinking-core mode to a faster lithiation finger mode corroborate with synchrotron characterization of large-format batteries, and can be rationalized by stress effects on transport at high-rate discharge. The finite incubation time of the lithiation fingers sets the intrinsic limitation for the rate capability (and thus the power) of NiO for electrochemical energy storage devices. The present work unravels the link between the nanoscale reaction pathways and the C-rate-dependent capacity loss, and provides guidance for the further design of battery materials that favors high C-rate charging.

  1. Macroscopic Properties of Restacked, Redox-Liquid Exfoliated Graphite and Graphite Mimics Produced in Bulk Quantities

    SciTech Connect (OSTI)

    Srivastava, Vikram K [ORNL; Quinlan, Ronald [ORNL; Agapov, Alexander L [ORNL; Dunlap, John R [ORNL; Nelson, Kimberly M [ORNL; Duranty, Edward R [ORNL; Sokolov, Alexei P [ORNL; Bhat, Gajanan [ORNL; Mays, Jimmy [ORNL

    2014-01-01T23:59:59.000Z

    The excellent properties exhibited by monolayer graphene have spurred the development of exfoliation techniques using bulk graphite to produce large quantities of pristine monolayer sheets. Development of simple chemistry to exfoliate and intercalate graphite and graphite mimics in large quantities is required for numerous applications. To determine the macroscopic behavior of restacked, exfoliated bulk materials, a systematic approach is presented using a simple, redox-liquid sonication process along to obtain large quantities of 2D and 3D hexagonally layered graphite, molybdenum disulfi de, and boron nitride, which are subsequently characterized to observe chemical and structural changes. For MoS 2 sonicated with the antioxidant sodium bisulfi te, results from Raman spectroscopy, X-ray diffraction, and electron microscopy indicate the presence of distorted phases from different polymorphs, and apparent nanotube structures in the bulk, restacked powder. Furthermore, using thermograviemtric analysis, the antioxidant enhances the resistance to oxidative degradation of MoS 2 , upon thermal treatment up to 900 C. The addition of the ionic antioxidant decreased dispersion stability in non-polar solvent, suggesting decreased compatibility with non-polar systems. Using simple chemical methods, the ability to generate tailored multidimensional layered materials with unique macroscopic properties is critical for numerous applications, including electrical devices, reinforced polymer composites, lithium ion capacitors, and chemical sensing.

  2. Antiproliferative effects of phenylaminonaphthoquinones are increased by ascorbate and associated with the appearance of a senescent phenotype in human bladder cancer cells

    SciTech Connect (OSTI)

    Felipe, K.B. [Laboratorio de Bioquímica Experimental, Departamento de Bioquímica, Universidade Federal de Santa Catarina, Florianópolis (Brazil)] [Laboratorio de Bioquímica Experimental, Departamento de Bioquímica, Universidade Federal de Santa Catarina, Florianópolis (Brazil); Benites, J. [Facultad de Ciencias de la Salud, Universidad Arturo Prat, Avenida Arturo Prat 2120, Casilla 121, Iquique (Chile)] [Facultad de Ciencias de la Salud, Universidad Arturo Prat, Avenida Arturo Prat 2120, Casilla 121, Iquique (Chile); Glorieux, C.; Sid, B.; Valenzuela, M. [Université Catholique de Louvain, Louvain Drug Research Institute, Toxicology and Cancer Biology Research Group (GTOX), Brussels (Belgium)] [Université Catholique de Louvain, Louvain Drug Research Institute, Toxicology and Cancer Biology Research Group (GTOX), Brussels (Belgium); Kviecinski, M.R.; Pedrosa, R.C. [Laboratorio de Bioquímica Experimental, Departamento de Bioquímica, Universidade Federal de Santa Catarina, Florianópolis (Brazil)] [Laboratorio de Bioquímica Experimental, Departamento de Bioquímica, Universidade Federal de Santa Catarina, Florianópolis (Brazil); Valderrama, J.A. [Departamento Química Orgánica, Pontificia Universidad Católica de Chile, Vicuña Mackenna 4860, Casilla 306, Santiago (Chile)] [Departamento Química Orgánica, Pontificia Universidad Católica de Chile, Vicuña Mackenna 4860, Casilla 306, Santiago (Chile); Levêque, Ph.; Gallez, B. [Université Catholique de Louvain, Louvain Drug Research Institute, Biomedical Magnetic Resonance Research Group (REMA), Brussels (Belgium)] [Université Catholique de Louvain, Louvain Drug Research Institute, Biomedical Magnetic Resonance Research Group (REMA), Brussels (Belgium); Verrax, J. [Université Catholique de Louvain, Louvain Drug Research Institute, Toxicology and Cancer Biology Research Group (GTOX), Brussels (Belgium)] [Université Catholique de Louvain, Louvain Drug Research Institute, Toxicology and Cancer Biology Research Group (GTOX), Brussels (Belgium); Buc Calderon, P., E-mail: pedro.buccalderon@uclouvain.be [Facultad de Ciencias de la Salud, Universidad Arturo Prat, Avenida Arturo Prat 2120, Casilla 121, Iquique (Chile); Université Catholique de Louvain, Louvain Drug Research Institute, Toxicology and Cancer Biology Research Group (GTOX), Brussels (Belgium)

    2013-04-19T23:59:59.000Z

    Highlights: •Phenylaminonaphthoquinones are redox cyclers able to form ROS. •Phenylaminonaphthoquinones plus ascorbate inhibit T24 cell growth. •Phenylaminonaphthoquinones plus ascorbate lead to necrotic-like cell death. •Phenylaminonaphthoquinones plus ascorbate impair cell cycle and affect MAPKs. •Phenylaminonaphthoquinones plus ascorbate induce a senescent cancer cell phenotype. -- Abstract: Quinone-containing molecules have been developed against cancer mainly for their redox cycling ability leading to reactive oxygen species (ROS) formation. We have previously shown that donor-acceptor phenylaminonaphthoquinones are biologically active against a panel of cancer cells. In this report, we explored the mechanisms involved in cancer cell growth inhibition caused by two phenylaminonaphthoquinones, namely Q7 and Q9, with or without ascorbate (ASC). The results show that Q7 and Q9 are both redox cyclers able to form ROS, which strongly inhibit the proliferation of T24 cells. Q9 was a better redox cycler than Q7 because of marked stabilization of the semiquinone radical species arising from its reduction by ascorbate. Indeed, ASC dramatically enhances the inhibitory effect of Q9 on cell proliferation. Q9 plus ASC impairs the cell cycle, causing a decrease in the number of cells in the G2/M phase without involving other cell cycle regulating key proteins. Moreover, Q9 plus ASC influences the MAPK signaling pathways, provoking the appearance of a senescent cancer cell phenotype and ultimately leading to necrotic-like cell death. Because cellular senescence limits the replicative capacity of cells, our results suggest that induction of senescence may be exploited as a basis for new approaches to cancer therapy.

  3. A one-volt p-InP/n-CdSe regenerative photoelectrochemical cell

    SciTech Connect (OSTI)

    Ang, P.G.P.; Sammells, A.F.

    1983-08-01T23:59:59.000Z

    Photoelectrochemical (PEC) cells have the potential utility of being used for either the direct conversion of solar energy to electricity as in regenerative devices or to generate stored redox species which can later be electrochemically discharged in a suitable cell. This latter approach has been particularly intriguing over the last few years. However, although several photoelectrochemical storage cells have been discussed, it has become increasingly desirable to have a high-voltage (approx. =1 V) PEC cell, so that the storage cell with which it is associated has some hope of being competitive with presently available commercial batteries.

  4. Bacteria in shear flow

    E-Print Network [OSTI]

    Marcos, Ph.D. Massachusetts Institute of Technology

    2011-01-01T23:59:59.000Z

    Bacteria are ubiquitous and play a critical role in many contexts. Their environment is nearly always dynamic due to the prevalence of fluid flow: creeping flow in soil, highly sheared flow in bodily conduits, and turbulent ...

  5. Dispersed flow film boiling

    E-Print Network [OSTI]

    Yoder, Graydon L.

    1980-01-01T23:59:59.000Z

    Dispersed flow consists of small liquid droplets entrained in a flowing vapor. This flow regime can occur in cryogenic equipment, in steam generators, and during nuclear reactor loss of coolant accidents. A theoretical ...

  6. ROLE OF MANGANESE REDUCTION/OXIDATION (REDOX) ON FOAMING AND MELT RATE IN HIGH LEVEL WASTE (HLW) MELTERS (U)

    SciTech Connect (OSTI)

    Jantzen, C; Michael Stone, M

    2007-03-30T23:59:59.000Z

    High-level nuclear waste is being immobilized at the Savannah River Site (SRS) by vitrification into borosilicate glass at the Defense Waste Processing Facility (DWPF). Control of the Reduction/Oxidation (REDOX) equilibrium in the DWPF melter is critical for processing high level liquid wastes. Foaming, cold cap roll-overs, and off-gas surges all have an impact on pouring and melt rate during processing of high-level waste (HLW) glass. All of these phenomena can impact waste throughput and attainment in Joule heated melters such as the DWPF. These phenomena are caused by gas-glass disequilibrium when components in the melter feeds convert to glass and liberate gases such as H{sub 2}O vapor (steam), CO{sub 2}, O{sub 2}, H{sub 2}, NO{sub x}, and/or N{sub 2}. During the feed-to-glass conversion in the DWPF melter, multiple types of reactions occur in the cold cap and in the melt pool that release gaseous products. The various gaseous products can cause foaming at the melt pool surface. Foaming should be avoided as much as possible because an insulative layer of foam on the melt surface retards heat transfer to the cold cap and results in low melt rates. Uncontrolled foaming can also result in a blockage of critical melter or melter off-gas components. Foaming can also increase the potential for melter pressure surges, which would then make it difficult to maintain a constant pressure differential between the DWPF melter and the pour spout. Pressure surges can cause erratic pour streams and possible pluggage of the bellows as well. For these reasons, the DWPF uses a REDOX strategy and controls the melt REDOX between 0.09 {le} Fe{sup 2+}/{summation}Fe {le} 0.33. Controlling the DWPF melter at an equilibrium of Fe{sup +2}/{summation}Fe {le} 0.33 prevents metallic and sulfide rich species from forming nodules that can accumulate on the floor of the melter. Control of foaming, due to deoxygenation of manganic species, is achieved by converting oxidized MnO{sub 2} or Mn{sub 2}O{sub 3} species to MnO during melter preprocessing. At the lower redox limit of Fe{sup +2}/{summation}Fe {approx} 0.09 about 99% of the Mn{sup +4}/Mn{sup +3} is converted to Mn{sup +2}. Therefore, the lower REDOX limits eliminates melter foaming from deoxygenation.

  7. Electron Transfer Reactivity Patterns at Chemically Modified Electrodes: Fundamentals and Application to the Optimization of Redox Recycling Amplification Systems

    SciTech Connect (OSTI)

    Adam Johan Bergren

    2006-05-01T23:59:59.000Z

    Electroanalytical chemistry is often utilized in chemical analysis and Fundamental studies. Important advances have been made in these areas since the advent of chemically modified electrodes: the coating of an electrode with a chemical film in order to impart desirable, and ideally, predictable properties. These procedures enable the exploitation of unique reactivity patterns. This dissertation presents studies that investigate novel reaction mechanisms at self-assembled monolayers on gold. In particular, a unique electrochemical current amplification scheme is detailed that relies on a selective electrode to enable a reactivity pattern that results in regeneration of the analyte (redox recycling). This regenerating reaction can occur up to 250 times for each analyte molecule, leading to a notable enhancement in the observed current. The requirements of electrode selectivity and the resulting amplification and detection limit improvements are described with respect to the heterogeneous and homogeneous electron transfer rates that characterize the system. These studies revealed that the heterogeneous electrolysis of the analyte should ideally be electrochemically reversible, while that for the regenerating agent should be held to a low level. Moreover, the homogeneous reaction that recycles the analyte should occur at a rapid rate. The physical selectivity mechanism is also detailed with respect to the properties of the electrode and redox probes utilized. It is shown that partitioning of the analyte into/onto the adlayer leads to the extraordinary selectivity of the alkanethiolate monolayer modified electrode. Collectively, these studies enable a thorough understanding of the complex electrode mechanism required for successful redox recycling amplification systems, Finally, in a separate (but related) study, the effect of the akyl chain length on the heterogeneous electron transfer behavior of solution-based redox probes is reported, where an odd-even oscillation (with respect to the number of methylene units in the alkyl chain) was observed. Characterization of the adlayers by infrared reflection spectroscopy, ellipsometry, and wetting revealed odd-even effects in the orientation of the terminal methyl group and hydrophobic character of the adlayers. Using these structural characterizations as a basis, several possible mechanisms that can account for the odd-even effect in the heterogeneous electron transfer rates of solution-based redox couples are discussed.

  8. Multiphase flow calculation software

    DOE Patents [OSTI]

    Fincke, James R. (Idaho Falls, ID)

    2003-04-15T23:59:59.000Z

    Multiphase flow calculation software and computer-readable media carrying computer executable instructions for calculating liquid and gas phase mass flow rates of high void fraction multiphase flows. The multiphase flow calculation software employs various given, or experimentally determined, parameters in conjunction with a plurality of pressure differentials of a multiphase flow, preferably supplied by a differential pressure flowmeter or the like, to determine liquid and gas phase mass flow rates of the high void fraction multiphase flows. Embodiments of the multiphase flow calculation software are suitable for use in a variety of applications, including real-time management and control of an object system.

  9. Fuel cell water transport

    DOE Patents [OSTI]

    Vanderborgh, Nicholas E. (Los Alamos, NM); Hedstrom, James C. (Los Alamos, NM)

    1990-01-01T23:59:59.000Z

    The moisture content and temperature of hydrogen and oxygen gases is regulated throughout traverse of the gases in a fuel cell incorporating a solid polymer membrane. At least one of the gases traverses a first flow field adjacent the solid polymer membrane, where chemical reactions occur to generate an electrical current. A second flow field is located sequential with the first flow field and incorporates a membrane for effective water transport. A control fluid is then circulated adjacent the second membrane on the face opposite the fuel cell gas wherein moisture is either transported from the control fluid to humidify a fuel gas, e.g., hydrogen, or to the control fluid to prevent excess water buildup in the oxidizer gas, e.g., oxygen. Evaporation of water into the control gas and the control gas temperature act to control the fuel cell gas temperatures throughout the traverse of the fuel cell by the gases.

  10. Redox signaling via the molecular chaperone BiP protects cells against endoplasmic reticulum-derived oxidative stress

    E-Print Network [OSTI]

    Wang, Jie

    Oxidative protein folding in the endoplasmic reticulum (ER) has emerged as a potentially significant source of cellular reactive oxygen species (ROS). Recent studies suggest that levels of ROS generated as a byproduct of ...

  11. Journal of Power Sources 142 (2005) 117124 Pressure drop behavior in the anode flow field of

    E-Print Network [OSTI]

    Zhao, Tianshou

    2005-01-01T23:59:59.000Z

    -house fabricated direct methanol fuel cell (DMFC). The anode flow field consisted of a single serpentine flow PEM fuel cells, a liquid feed direct methanol fuel cell (DMFC), using a solid polymer membrane for portable electronic devices, electric vehicles, and other mobile and stationery ap- plications. Driven

  12. Freshwater Flow Charts - 1995

    SciTech Connect (OSTI)

    Kaiper, G V

    2003-11-21T23:59:59.000Z

    This report covers the following: (1) Explanation of Charts Showing Freshwater Flow in 1995; (2) Estimated U.S. Freshwater Flow in 1995 (chart); (3) Estimated California Freshwater Flow in 1995 (chart); (4) Estimated New Mexico Freshwater Flow in 1995 (chart); and (5) Web locations and credits.

  13. Structural, chemical, and electrochemical characteristics of LaSr2Fe2CrO9--based solid oxide fuel cell anodes

    E-Print Network [OSTI]

    Poeppelmeier, Kenneth R.

    -of-the-art solid oxide fuel cell (SOFC) anode is Ni-8-mole% yttria stabilized zirconia (YSZ), which performs very Available online 5 March 2012 Keywords: Solid oxide fuel cell Perovskite Oxide anode Redox Sulfur tolerance Solid oxide fuel cells with LaSr2Fe2CrO9-­Gd0.1Ce0.9O2- composite anodes were tested in H2, H2S

  14. Portable wastewater flow meter

    DOE Patents [OSTI]

    Hunter, Robert M. (320 S. Wilson Ave., Bozeman, MT 59715)

    1990-01-01T23:59:59.000Z

    A portable wastewater flow meter particularly adapted for temporary use at a single location in measuring the rate of liquid flow in a circular entrance conduit of a sewer manhole both under free flow and submerged, open channel conditions and under full pipe, surcharged conditions, comprising an apparatus having a cylindrical external surface and an inner surface that constricts the flow through the apparatus in such a manner that a relationship exists between (1) the difference between the static pressure head of liquid flowing through the entrance of the apparatus and the static pressure head of liquid flowing through the constriction, and (2) the rate of liquid flow through the apparatus.

  15. Portable wastewater flow meter

    DOE Patents [OSTI]

    Hunter, Robert M. (320 S. Wilson Ave., Bozeman, MT 59715)

    1999-02-02T23:59:59.000Z

    A portable wastewater flow meter particularly adapted for temporary use at a single location in measuring the rate of liquid flow in a circular entrance conduit of a sewer manhole both under free flow and submerged, open channel conditions and under fill pipe, surcharged conditions, comprising an apparatus having a cylindrical external surface and an inner surface that constricts the flow through the apparatus in such a manner that a relationship exists between (1) the difference between the static pressure head of liquid flowing through the entrance of the apparatus and the static pressure head of liquid flowing through the constriction, and (2) the rate of liquid flow through the apparatus.

  16. Soluble Lead Flow Battery: Soluble Lead Flow Battery Technology

    SciTech Connect (OSTI)

    None

    2010-09-01T23:59:59.000Z

    GRIDS Project: General Atomics is developing a flow battery technology based on chemistry similar to that used in the traditional lead-acid battery found in nearly every car on the road today. Flow batteries store energy in chemicals that are held in tanks outside the battery. When the energy is needed, the chemicals are pumped through the battery. Using the same basic chemistry as a traditional battery but storing its energy outside of the cell allows for the use of very low cost materials. The goal is to develop a system that is far more durable than today’s lead-acid batteries, can be scaled to deliver megawatts of power, and which lowers the cost of energy storage below $100 per kilowatt hour.

  17. West Valley glass product qualification durability studies, FY 1987--1988: Effects of composition, redox state, thermal history, and groundwater

    SciTech Connect (OSTI)

    Reimus, M.A.H.; Piepel, G.F.; Mellinger, G.B.; Bunnell, L.R.

    1988-11-01T23:59:59.000Z

    The product qualification subtask of the West Valley Support Task (WVST) at Pacific Northwest Laboratory (PNL) provides support for the waste form qualification efforts at West Valley Nuclear Services Co. Testing is being conducted to determine waste form chemical durability in support of these efforts. The effects of composition, ferrous/ferric ratio (redox state), thermal history, and groundwater are being investigated. Glasses were tested using modified Materials Characterization Center (MCC) -3 and MCC-1 test methods. Results obtained in fiscal years (FY) 1987 and 1988 are presented here. 13 refs., 27 figs., 36 tabs.

  18. Structural, Spectroscopic, And Theoretical Elucidation of a Redox-Active Pincer-Type Ancillary Applied in Catalysis

    SciTech Connect (OSTI)

    Adhikari, D.; Mossin, S.; Basuli, F.; Huffman, J.C.; Szilagyi, R.K.; Meyer, K.; Mindiola, D.J.

    2009-05-11T23:59:59.000Z

    Pincer-type ligands are believed to be very robust scaffolds that can support multifarious functionalities as well as highly reactive metal motifs applied in organometallic chemistry, especially in the realm of catalysis. In this paper, we describe the redox and, therefore, noninnocent behavior of a PNP (PNP{sup -} = N[2-P(CHMe{sub 2}){sub 2}-4-methylphenyl]{sub 2}) pincer ancillary bound to nickel. A combination of structural, spectroscopic, and theoretical techniques suggests that this type of framework can house an electron hole when coordinated to Ni(II).

  19. NIRT: Redox and Conduction Routing in Molecular Electronics Hctor D. Abrua, Chemistry and Chemical Biology

    E-Print Network [OSTI]

    Danforth, Bryan Nicholas

    -Loeb, Entomology­Geneva Campus $106,408, U.S. Department of Agriculture Nanohybrid Membranes for Fuel Cells,240, Department of Health and Human Services The Role of the Cell Cycle in Luteal Regression Susan M. Quirk--Transmission of MDR Salmonella Lorin D. Warnick, Population Medicine and Diagnostic Sciences $1,119,959, Department

  20. Microbial individuality: how single-cell heterogeneity enables population level strategies

    E-Print Network [OSTI]

    Martins, Bruno M. C.; Locke, James C. W.

    2015-02-05T23:59:59.000Z

    A,B). Technologies that deliver individual cell resolution data, such as time-lapse microscopy, flow cytometry, microfluidics and single-cell RNA-seq, are being increasingly used to precisely quantify cell-to-cell heterogeneity in isogenic...

  1. The Hydrodynamics of Flow Stimuli Matthew J. McHenry and James C. Liao

    E-Print Network [OSTI]

    McHenry, Matt

    · Rheotaxis · Swimming · Turbulence · Vortex street · Unsteady flow 1 Introduction The lateral line system · Hair cell · Ka´rma´n gait · Lateral line · Localization · Neuromast · Predation · Reynolds number

  2. Pore-Scale Characterization of Biogeochemical Controls on Iron and Uranium Speciation under Flow Conditions

    SciTech Connect (OSTI)

    Pearce, Carolyn I.; Wilkins, Michael J.; Zhang, Changyong; Heald, Steve M.; Fredrickson, Jim K.; Zachara, John M.

    2012-09-17T23:59:59.000Z

    Etched silicon microfluidic pore network models (micromodels) with controlled chemical and redox gradients, mineralogy, and microbiology under continuous flow conditions are used for the incremental development of complex microenvironments that simulate subsurface conditions. We demonstrate the colonization of micromodel pore spaces by an anaerobic Fe(III)-reducing bacterial species (Geobacter sulfurreducens) and the enzymatic reduction of a bioavailable Fe(III) phase within this environment. Using both X-ray Microprobe and X-ray Absorption Spectroscopy, we investigate the combined effects of the precipitated Fe(III) phases and the microbial population on uranium biogeochemistry under flow conditions. Precipitated Fe(III) phases within the micromodel were most effectively reduced in the presence of an electron shuttle (AQDS), and Fe(II) ions adsorbed onto the precipitated mineral surface without inducing any structural change. In the absence of Fe(III), U(VI) was effectively reduced by the microbial population to insoluble U(IV), which was precipitated in discrete regions associated with biomass. In the presence of Fe(III) phases, however, both U(IV) and U(VI) could be detected associated with biomass, suggesting re-oxidation of U(IV) by localized Fe(III) phases. These results demonstrate the importance of the spatial localization of biomass and redox active metals, and illustrate the key effects of pore-scale processes on contaminant fate and reactive transport.

  3. Numerical simulation of flow separation control by oscillatory fluid injection 

    E-Print Network [OSTI]

    Resendiz Rosas, Celerino

    2005-08-29T23:59:59.000Z

    In this work, numerical simulations of flow separation control are performed. The sep-aration control technique studied is called 'synthetic jet actuation'. The developed code employs a cell centered finite volume scheme which handles viscous...

  4. Hydrologic Flow Controls on Biologic Iron(III) Reduction in

    E-Print Network [OSTI]

    Burgos, William

    for energy that likely increased cell synthesis, and decreased the concentration of sorbed Fe(II) that) in a goethite-coated sand was bioreduced by the DMRB Shewanella putrefaciens CN32 in a flow-through column

  5. Coupled modeling of groundwater flow solute transport, chemical reactions and microbial processes in the 'SP' island

    SciTech Connect (OSTI)

    Samper, Javier; Molinero, Jorg; Changbing, Yang; Zhang, Guoxiang

    2003-12-01T23:59:59.000Z

    The Redox Zone Experiment was carried out at the Aespoe HRL in order to study the redox behavior and the hydrochemistry of an isolated vertical fracture zone disturbed by the excavation of an access tunnel. Overall results and interpretation of the Redox Zone Project were reported by /Banwart et al, 1995/. Later, /Banwart et al, 1999/ presented a summary of the hydrochemistry of the Redox Zone Experiment. Coupled groundwater flow and reactive transport models of this experiment were carried out by /Molinero, 2000/ who proposed a revised conceptual model for the hydrogeology of the Redox Zone Experiment which could explain simultaneously measured drawdown and salinity data. The numerical model was found useful to understand the natural system. Several conclusions were drawn about the redox conditions of recharge waters, cation exchange capacity of the fracture zone and the role of mineral phases such as pyrite, calcite, hematite and goethite. This model could reproduce the measured trends of dissolved species, except for bicarbonate and sulfate which are affected by microbially-mediated processes. In order to explore the role of microbial processes, a coupled numerical model has been constructed which accounts for water flow, reactive transport and microbial processes. The results of this model is presented in this report. This model accounts for groundwater flow and reactive transport in a manner similar to that of /Molinero, 2000/ and extends the preliminary microbial model of /Zhang, 2001/ by accounting for microbially-driven organic matter fermentation and organic matter oxidation. This updated microbial model considers simultaneously the fermentation of particulate organic matter by yeast and the oxidation of dissolved organic matter, a product of fermentation. Dissolved organic matter is produced by yeast and serves also as a substrate for iron-reducing bacteria. Model results reproduce the observed increase in bicarbonate and sulfate concentration, thus adding additional evidence for the possibility of organic matter oxidation as the main source of bicarbonate. Model results indicate that pH and Eh are relatively stable. The dissolution-precipitation trends of hematite, pyrite and calcite also coincide with those indicated by the conceptual model. A thorough sensitivity analysis has been performed for the most relevant microbial parameters as well as for initial and boundary POC and DOC concentrations. The results of such analysis indicate that computed concentrations of bicarbonate, sulfate and DOC are sensitive to most of the microbial parameters, including specific growth rates, half-saturation constants, proportionality coefficients and yield coefficients. Model results, however, are less sensitive to the yield coefficient of DOC to iron-reducer bacteria. The sensitivity analysis indicates that changes in fermentation microbial parameters affect the growth of the iron-reducer, thus confirming the interconnection of both microbial processes. Computed concentrations of bicarbonate and sulfate are found to be sensitive to changes in the initial concentration of POC and the boundary concentration of DOC, but they lack sensitivity to the initial concentration of DOC and the boundary concentration of POC. The explanation for such result is related to the fact that POC has a low mobility due to its large molecular weight. DOC, however, can migrate downwards. Although a coupled hydro-bio-geochemical 1-D model can reproduce the observed ''unexpected'' increase of concentrations of bicarbonate and sulfate at a depth of 70 m, further modeling work is required in order to obtain a similar conclusion under the more realistic two dimensional conditions of the fracture zone.

  6. Parallel-Flow-Shear Driven Low-Frequency Plasma Instability

    SciTech Connect (OSTI)

    Ishiguro, Seiji [Theory and Computer Simulation Center, National Institute for Fusion Science, Toki-shi, Gifu 509-5292 (Japan); Matsumoto, Noriaki; Kaneko, Toshiro; Hatakeyama, Rikizo [Department of Electronic Engineering, Tohoku University, Sendai 980-8579 (Japan)

    2004-12-01T23:59:59.000Z

    Full three dimensional Particle-in-Cell (PIC) simulations are performed in order to investigate effects of field-aligned (parallel) ion flow shears on low-frequency plasma instabilities. It is shown that the parallel ion flow velocity shear can induce the ion-acoustic instability, even when the ion flow velocity is so small that the instability can not take place. Simulation results are consistent with the analysis based on the local theory.

  7. Electrochemical DNA biosensor for detection of porcine oligonucleotides using ruthenium(II) complex as intercalator label redox

    SciTech Connect (OSTI)

    Halid, Nurul Izni Abdullah; Hasbullah, Siti Aishah; Heng, Lee Yook; Karim, Nurul Huda Abd [School of Chemical Sciences and Food Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan (Malaysia); Ahmad, Haslina; Harun, Siti Norain [Chemistry Department, Faculty of Science, Universiti Putra Malaysia, 43400, Serdang, Selangor (Malaysia)

    2014-09-03T23:59:59.000Z

    A DNA biosensor detection of oligonucleotides via the interactions of porcine DNA with redox active complex based on the electrochemical transduction is described. A ruthenium(II) complex, [Ru(bpy){sub 2}(PIP)]{sup 2+}, (bpy = 2,2?bipyridine, PIP = 2-phenylimidazo[4,5-f[[1,10-phenanthroline]) as DNA label has been synthesized and characterized by 1H NMR and mass spectra. The study was carried out by covalent bonding immobilization of porcine aminated DNA probes sequences on screen printed electrode (SPE) modified with succinimide-acrylic microspheres and [Ru(bpy){sub 2}(PIP)]{sup 2+} was used as electrochemical redox intercalator label to detect DNA hybridization event. Electrochemical detection was performed by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) over the potential range where the ruthenium (II) complex was active. The results indicate that the interaction of [Ru(bpy){sub 2}(PIP)]{sup 2+} with hybridization complementary DNA has higher response compared to single-stranded and mismatch complementary DNA.

  8. Ultrasonic flow metering system

    DOE Patents [OSTI]

    Gomm, Tyler J. (Meridian, ID); Kraft, Nancy C. (Idaho Falls, ID); Mauseth, Jason A. (Pocatello, ID); Phelps, Larry D. (Pocatello, ID); Taylor, Steven C. (Idaho Falls, ID)

    2002-01-01T23:59:59.000Z

    A system for determining the density, flow velocity, and mass flow of a fluid comprising at least one sing-around circuit that determines the velocity of a signal in the fluid and that is correlatable to a database for the fluid. A system for determining flow velocity uses two of the inventive circuits with directional transmitters and receivers, one of which is set at an angle to the direction of flow that is different from the others.

  9. Dispersion of swimming algae in laminar and turbulent channel flows: theory and simulations

    E-Print Network [OSTI]

    Croze, O A; Ahmed, M; Bees, M A; Brandt, L

    2012-01-01T23:59:59.000Z

    Algal swimming is often biased by environmental cues, e.g. gravitational and viscous torques drive cells towards downwelling fluid (gyrotaxis). In view of biotechnological applications, it is important to understand how such biased swimming affects cell dispersion in a flow. Here, we study the dispersion of gyrotactic swimming algae in laminar and turbulent channel flows. By direct numerical simulation (DNS) of cell motion within upwelling and downwelling channel flows, we evaluate time-dependent measures of dispersion for increasing values of the flow Peclet (Reynolds) numbers, Pe (Re). Furthermore, we derive an analytical `swimming Taylor-Aris dispersion' theory, using flow-dependent transport parameters given by existing microscopic models. In the laminar regime, DNS results and analytical predictions compare very well, providing the first confirmation that cells' response to flow is best described by the generalized-Taylor-dispersion microscopic model. We predict that cells drift along a channel faster th...

  10. Membrane-less hydrogen bromine flow battery William A. Braff1

    E-Print Network [OSTI]

    Bazant, Martin Z.

    refined and optimized over several decades. More recently, a laminar flow fuel cell based on borohydride batteries [23, 27], as well as methanol [25], formic acid [24], and hydrogen fuel cells [29]. However, none

  11. Elbow mass flow meter

    DOE Patents [OSTI]

    McFarland, Andrew R. (College Station, TX); Rodgers, John C. (Santa Fe, NM); Ortiz, Carlos A. (Bryan, TX); Nelson, David C. (Santa Fe, NM)

    1994-01-01T23:59:59.000Z

    Elbow mass flow meter. The present invention includes a combination of an elbow pressure drop generator and a shunt-type mass flow sensor for providing an output which gives the mass flow rate of a gas that is nearly independent of the density of the gas. For air, the output is also approximately independent of humidity.

  12. Modeling Water Management in Polymer-Electrolyte Fuel Cells

    E-Print Network [OSTI]

    Weber, Adam; Department of Chemical Engineering, University of California, Berkeley

    2008-01-01T23:59:59.000Z

    side of the cell in both crossflow and flow-under-the-ribgas flow is probably crossflow. This situation was looked atbalances. They found that crossflow increases the average

  13. To be published in IEEE Aerospace Conference Proceedings, 2003, Cat No. 0-7803-7651-X/03/$17.00 2003 IEEE Planar REDOX and Conductivity Sensors

    E-Print Network [OSTI]

    Kounaves, Samuel P.

    To be published in IEEE Aerospace Conference Proceedings, 2003, Cat No. 0-7803-7651-X/03 are AeroRedox2C14 - 1 #12;To be published in IEEE Aerospace Conference Proceedings, 2003, Cat No. 0. BIOGRAPHIES 1. INTRODUCTION This paper extends the work reported at last year's IEEE Aerospace conference

  14. Structural basis of inter-domain electron transfer in Ncb5or, a redox enzyme implicated in diabetes and lipid metabolism

    E-Print Network [OSTI]

    Deng, Bin

    2011-12-31T23:59:59.000Z

    NADH cytochrome b5 oxidoreductase (Ncb5or) is a multi-domain redox enzyme found in all animal tissues and associated with the endoplasmic reticulum (ER). Ncb5or contains (from N-terminus to C terminus) a novel N-terminal region, the b5 domain (Ncb5...

  15. Back-reactions, short-circuits, leaks and other energy wasteful reactions in biological electron transfer: Redox tuning to survive life in O2

    E-Print Network [OSTI]

    Review Back-reactions, short-circuits, leaks and other energy wasteful reactions in biological Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland c s t r a c t The energy-converting redox enzymes perform productive reactions efficiently despite

  16. A designed redox-controlled caspase Witold A. Witkowski and Jeanne A. Hardy*

    E-Print Network [OSTI]

    Hardy, Jeanne

    of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01003 Received 18 March 2011, the activity of the IAPs is regulated by proapoptotic Smac/Diablo and Bcl family mem- bers.8,9 Thus, appropriate regulation of caspase ac- tivity is complex and is of paramount importance for appropriate cell

  17. Computational Biorheology of Human Blood Flow in Health and Disease DMITRY A. FEDOSOV,1

    E-Print Network [OSTI]

    Dao, Ming

    with results obtained using this computational framework for blood flow in malaria and sickle cell anemia in the later stages of the intra-cell parasite development.36 Sickle cell anemia is another blood disorder. Keywords--Hematologic disorders, Dissipative particle dynamics, Coarse-graining, Malaria, Sickle cell

  18. FINAL REPORT INTEGRATED DM1200 MELTER TESTING OF REDOX EFFECTS USING HLW AZ-101 AND C-106/AY-102 SIMULANTS VSL-04R4800-1 REV 0 5/6/

    SciTech Connect (OSTI)

    KRUGER AA; MATLACK KS; GONG W; BARDAKCI T; D'ANGELO NA; LUTZE W; BIZOT PM; CALLOW RA; BRANDYS M; KOT WK; PEGG IL

    2011-12-29T23:59:59.000Z

    This report documents melter and off-gas performance results obtained on the DM1200 HLW Pilot Melter during processing of AZ-101 and C-106/AY-102 HLW simulants. The tests reported herein are a subset of three tests from a larger series of tests described in the Test Plan for the work; results from the remaining tests will be reported separately. Three nine day tests, one with AZ-101 and two with C-106/AY-102 feeds were conducted with variable amounts of added sugar to address the effects of redox. The test with AZ-101 included ruthenium spikes to also address the effects of redox on ruthenium volatility. One of tests addressed the effects of increased flow-sheet nitrate levels using C-106/AY-102 feeds. With high nitrate/nitrite feeds (such as WTP LAW feeds), reductants are required to prevent melt foaming and deleterious effects on glass production rates. Sugar is the baseline WTP reductant for this purpose. WTP HLW feeds typically have relatively low nitrate/nitrite content in comparison to the organic carbon content and, therefore, have typically not required sugar additions. However, HLW feed variability, particularly with respect to nitrate levels, may necessitate the use of sugar in some instances. The tests reported here investigate the effects of variable sugar additions to the melter feed as well as elevated nitrate levels in the waste. Variables held constant to the extent possible included melt temperature, bubbling rate, plenum temperature, cold cap coverage, the waste simulant composition, and the target glass composition. The principal objectives of the DM1200 melter testing were to determine the achievable glass production rates for simulated HLW feeds with variable amounts of added sugar and increased nitrate levels; characterize melter off-gas emissions; characterize the performance of the prototypical off-gas system components as well as their integrated performance; characterize the feed, glass product, and off-gas effluents; and perform pre- and post test inspections of system components. The specific objectives (including test success criteria) of this testing, along with how each objective was met, are outlined in a table.

  19. Redox potential evolution of nitric species and plutonium in HNO{sub 3}-HNO{sub 2} system

    SciTech Connect (OSTI)

    Larabi-Gruet, N.; Gwinner, B.; Robin, R.; Fauvet, P. [CEA, DEN, DPC, SCCME, Lab Etud Corros Non Aqueuse, F-91191 Gif Sur Yvette, (France); Buravand, E. [CEA, DEN, DRCP, SE2A, Laboratoire d'Etudes de dissolution, F-30207 Bagnol/Ceze, (France)

    2012-07-01T23:59:59.000Z

    In France, the reprocessing process of spent fuel is carried out using the Purex process. The first chemical step of this process is the dissolution of the spent fuel in aqueous concentrated nitric acid. This dissolution solution is composed of many oxidizing species and it is necessary to understand the chemistry of these species to apprehend the behavior of structural materials. The redox potential is a useful discriminate variable to differentiate the effect of each species. In this framework, only the effect of NO{sub 3}{sup -}/HNO{sub 2} couple and PuO{sub 2}{sup 2+}/Pu{sup 4+} couple were investigated. These species were chosen because one is the main couple of medium and the other has a high standard potential. Their influence was investigated from the Nernst's equation. (authors)

  20. Redox control of electric melters with complex feed compositions. Part II: preliminary limits for radioactive waste melters

    SciTech Connect (OSTI)

    Bickford, D F; Diemer, Jr, R B; Iverson, D C

    1985-01-01T23:59:59.000Z

    Melter redox control is necessary for safe and continued melter operation. A combination of feed composition control, melter operational controls and monitors, and periodic determination of product glass redox state is sufficient to meet operating and safety requirements. Mossbauer spectroscopy, or other methods which determine the Fe(II)/Fe(III) ratio of the glass product, can be used to determine the oxidation state of the glass and thereby assess operating conditions. Slightly reducing conditions can eliminate radio-Ru volatility by suppressing the formation of RuO4. Reducing conditions also limit foaming resulting from the release of oxygen as transition metal oxides are dissolved in the melt. The calcination and partial combustion of organic compounds in the melter feed generates combustible mixtures of CO, H2 and benzene. The organics must be essentially completely incinerated to avoid the accumulation of combustible offgas mixtures, and prevent fouling of the equipment by soot and tars. Operation of the melter plenum above the autoignition temperature, metering in of purge air in excess of that required for complete combustion, and dilution by water vapor from reacted feed all preclude this occurrence in the melter. Prevention of dangerous offgas compositions after water vapor removal is assured by combustion in the melter, the addition of dilution air, and by continuous monitoring by % Lower Explosive Limit meters. Melter reducing power must be restricted to prevent formation of molten sulfides or selenides in the melter, and to prevent carburization and sulfidation attack of Inconel-690 melter components. Control of average oxygen partial pressure in the melter plenum is insufficient to assure prevention of localized attack of Inconel-690. An additional requirement is therefore necessary, that no soot or tarry substances be deposited on the Inconel-690.

  1. Fuel cell membrane hydration and fluid metering

    DOE Patents [OSTI]

    Jones, Daniel O. (Glenville, NY); Walsh, Michael M. (Fairfield, CT)

    2003-01-01T23:59:59.000Z

    A hydration system includes fuel cell fluid flow plate(s) and injection port(s). Each plate has flow channel(s) with respective inlet(s) for receiving respective portion(s) of a given stream of reactant fluid for a fuel cell. Each injection port injects a portion of liquid water directly into its respective flow channel. This serves to hydrate at least corresponding part(s) of a given membrane of the corresponding fuel cell(s). The hydration system may be augmented by a metering system including flow regulator(s). Each flow regulator meters an injecting at inlet(s) of each plate of respective portions of liquid into respective portion(s) of a given stream of fluid by corresponding injection port(s).

  2. Fuel cell membrane hydration and fluid metering

    DOE Patents [OSTI]

    Jones, Daniel O. (Glenville, NY); Walsh, Michael M. (Fairfield, CT)

    1999-01-01T23:59:59.000Z

    A hydration system includes fuel cell fluid flow plate(s) and injection port(s). Each plate has flow channel(s) with respective inlet(s) for receiving respective portion(s) of a given stream of reactant fluid for a fuel cell. Each injection port injects a portion of liquid water directly into its respective flow channel in order to mix its respective portion of liquid water with the corresponding portion of the stream. This serves to hydrate at least corresponding part(s) of a given membrane of the corresponding fuel cell(s). The hydration system may be augmented by a metering system including flow regulator(s). Each flow regulator meters an injecting at inlet(s) of each plate of respective portions of liquid into respective portion(s) of a given stream of fluid by corresponding injection port(s).

  3. 851 S.W. Sixth Avenue, Suite 1100 Steve Crow 503-222-5161 Portland, Oregon 97204-1348 Executive Director 800-452-5161

    E-Print Network [OSTI]

    a grid storage solution in the form of a large Zinc Redox flow battery. ZAI is trying to bring down Redox Battery for Utility scale storage(Now) Fuel Cell for electric vehicles (Soon) Outsourcing sub the cost of energy storage by utilizing chemical efficiencies, with a goal of providing storage large

  4. Turbulent flow in graphene

    E-Print Network [OSTI]

    Kumar S. Gupta; Siddhartha Sen

    2010-06-05T23:59:59.000Z

    We demonstrate the possibility of a turbulent flow of electrons in graphene in the hydrodynamic region, by calculating the corresponding turbulent probability density function. This is used to calculate the contribution of the turbulent flow to the conductivity within a quantum Boltzmann approach. The dependence of the conductivity on the system parameters arising from the turbulent flow is very different from that due to scattering.

  5. Precision electron flow measurements in a disk transmission line.

    SciTech Connect (OSTI)

    Clark, Waylon T.; Pelock, Michael D.; Martin, Jeremy Paul; Jackson, Daniel Peter Jr.; Savage, Mark Edward; Stoltzfus, Brian Scott; Mendel, Clifford Will, Jr.; Pointon, Timothy David

    2008-01-01T23:59:59.000Z

    An analytic model for electron flow in a system driving a fixed inductive load is described and evaluated with particle in cell simulations. The simple model allows determining the impedance profile for a magnetically insulated transmission line given the minimum gap desired, and the lumped inductance inside the transition to the minimum gap. The model allows specifying the relative electron flow along the power flow direction, including cases where the fractional electron flow decreases in the power flow direction. The electrons are able to return to the cathode because they gain energy from the temporally rising magnetic field. The simulations were done with small cell size to reduce numerical heating. An experiment to compare electron flow to the simulations was done. The measured electron flow is {approx}33% of the value from the simulations. The discrepancy is assumed to be due to a reversed electric field at the cathode because of the inductive load and falling electron drift velocity in the power flow direction. The simulations constrain the cathode electric field to zero, which gives the highest possible electron flow.

  6. A stochastic flow rule for granular materials

    E-Print Network [OSTI]

    Ken Kamrin; Martin Z. Bazant

    2006-09-19T23:59:59.000Z

    There have been many attempts to derive continuum models for dense granular flow, but a general theory is still lacking. Here, we start with Mohr-Coulomb plasticity for quasi-2D granular materials to calculate (average) stresses and slip planes, but we propose a "stochastic flow rule" (SFR) to replace the principle of coaxiality in classical plasticity. The SFR takes into account two crucial features of granular materials - discreteness and randomness - via diffusing "spots" of local fluidization, which act as carriers of plasticity. We postulate that spots perform random walks biased along slip-lines with a drift direction determined by the stress imbalance upon a local switch from static to dynamic friction. In the continuum limit (based on a Fokker-Planck equation for the spot concentration), this simple model is able to predict a variety of granular flow profiles in flat-bottom silos, annular Couette cells, flowing heaps, and plate-dragging experiments -- with essentially no fitting parameters -- although it is only expected to function where material is at incipient failure and slip-lines are inadmissible. For special cases of admissible slip-lines, such as plate dragging under a heavy load or flow down an inclined plane, we postulate a transition to rate-dependent Bagnold rheology, where flow occurs by sliding shear planes. With different yield criteria, the SFR provides a general framework for multiscale modeling of plasticity in amorphous materials, cycling between continuum limit-state stress calculations, meso-scale spot random walks, and microscopic particle relaxation.

  7. Analysis of Fuel Cell Systems Rangan Banerjee

    E-Print Network [OSTI]

    Banerjee, Rangan

    Analysis of Fuel Cell Systems Rangan Banerjee Energy Systems Engineering IIT Bombay Lecture in CEP Course on `Fuel Cell' at IIT 14th November 2007 #12;Overview of Talk Energy Crisis ­ Motivation for fuel biological Hydrogen Gasification Fermentation Cracking + Shift Reaction Fuel Cell #12;ENERGY FLOW DIAGRAM

  8. EE580 Solar Cells Todd J. Kaiser

    E-Print Network [OSTI]

    Kaiser, Todd J.

    7/21/2010 1 EE580 ­ Solar Cells Todd J. Kaiser · Lecture 02 Microfabrication ­ A combination · Photolithograpy · Depostion · Etching 1 Montana State University: Solar Cells Lecture 2: Microfabrication Flow Montana State University: Solar Cells Lecture 2: Microfabrication Questions · What is heat? · Heat

  9. In situ PEM fuel cell water measurements

    SciTech Connect (OSTI)

    Borup, Rodney L [Los Alamos National Laboratory; Mukundan, Rangachary [Los Alamos National Laboratory; Davey, John R [Los Alamos National Laboratory; Spendalow, Jacob S [Los Alamos National Laboratory

    2008-01-01T23:59:59.000Z

    Efficient PEM fuel cell performance requires effective water management. The materials used, their durability, and the operating conditions under which fuel cells run, make efficient water management within a practical fuel cell system a primary challenge in developing commercially viable systems. We present experimental measurements of water content within operating fuel cells. in response to operational conditions, including transients and freezing conditions. To help understand the effect of components and operations, we examine water transport in operating fuel cells, measure the fuel cell water in situ and model the water transport within the fuel cell. High Frequency Resistance (HFR), AC Impedance and Neutron imaging (using NIST's facilities) were used to measure water content in operating fuel cells with various conditions, including current density, relative humidity, inlet flows, flow orientation and variable GDL properties. Ice formation in freezing cells was also monitored both during operation and shut-down conditions.

  10. Microelectromechanical flow control apparatus

    DOE Patents [OSTI]

    Okandan, Murat (NE Albuquerque, NM)

    2009-06-02T23:59:59.000Z

    A microelectromechanical (MEM) flow control apparatus is disclosed which includes a fluid channel formed on a substrate from a first layer of a nonconducting material (e.g. silicon nitride). A first electrode is provided on the first layer of the nonconducting material outside the flow channel; and a second electrode is located on a second layer of the nonconducting material above the first layer. A voltage applied between the first and second electrodes deforms the fluid channel to increase its cross-sectional size and thereby increase a flow of a fluid through the channel. In certain embodiments of the present invention, the fluid flow can be decreased or stopped by applying a voltage between the first electrode and the substrate. A peristaltic pumping of the fluid through the channel is also possible when the voltage is applied in turn between a plurality of first electrodes and the substrate. A MEM flow control assembly can also be formed by providing one or more MEM flow control devices on a common substrate together with a submicron filter. The MEM flow control assembly can optionally include a plurality of pressure sensors for monitoring fluid pressure and determining flow rates through the assembly.

  11. Electron Transfer Dynamics in Efficient Molecular Solar Cells

    SciTech Connect (OSTI)

    Meyer, Gerald John

    2014-10-01T23:59:59.000Z

    This research provided new mechanistic insights into surface mediated photochemical processes relevant to solar energy conversion. In this past three years our research has focused on oxidation photo-redox chemistry and on the role surface electric fields play on basic spectroscopic properties of molecular-semiconductor interfaces. Although this research as purely fundamental science, the results and their interpretation have relevance to applications in dye sensitized and photogalvanic solar cells as well as in the storage of solar energy in the form of chemical bonds.

  12. Regulation of Bone Morphogenetic Protein 9 by Redox-Dependent Proteolysis

    E-Print Network [OSTI]

    Wei, Zhenquan; Salmon, Richard M.; Upton, Paul D.; Morrell, Nicholas W.; Li, Wei

    2014-09-18T23:59:59.000Z

    using 1ZKZ as search model (31,32). Model building was carried out using Coot (33) and refinement with REFMAC5 (34) and Phenix refine (35). Figures were produced using Coot and PyMOL (The PyMOL Molecular Graphics System, Version 1.2r3pre, Schrödinger... ., White, K., Sasak, H., Kusmik, W., Smart, J., Oppermann, H., Rueger, D. C., and Tucker, R. F. (1994) Osteogenic protein-1 (OP-1) expression and processing in Chinese hamster ovary cells: isolation of a soluble complex containing the mature and pro...

  13. Microfluidic Hydrogen Fuel Cell with a Liquid Electrolyte Ranga S. Jayashree, Michael Mitchell, Dilip Natarajan, Larry J. Markoski, and

    E-Print Network [OSTI]

    Kenis, Paul J. A.

    Letters Microfluidic Hydrogen Fuel Cell with a Liquid Electrolyte Ranga S. Jayashree, Michael and characterization of a microfluidic hydrogen fuel cell with a flowing sulfuric acid solution instead of a Nafion, and electrolyte flow rate on fuel cell performance to obtain a maximum power density of 191 mW/cm2. This flowing

  14. Direct Ethanol Fuel Cells: Platinum/Rhodium Anode

    E-Print Network [OSTI]

    Petta, Jason

    Direct Ethanol Fuel Cells: Platinum/Rhodium Anode Catalysis Ken Ellis-Guardiola PCCM REU 2010 #12 EtOH+3H2O 12H+ +2CO2+ 12e- Pt C 4H+ + 4e- + O2 2H2O O2 Anode Cathode The Direct Ethanol Fuel Cell #12 Fuel Cell Test ~ 1.5 mg Pt loading. 1.0 M Ethanol flowing at 1 ml/min. O2 flowing at 100 ml/min. Cells

  15. copyrisht@ree2bythen-""i"",,R3il:'J[$H#"",i*tTy"t"*r1"'J?rt;""mission orthecopyrightowner. Toward Orthogonal Self-Assembly of Redox Active

    E-Print Network [OSTI]

    Prentiss, Mara

    Orthogonal Self-Assembly of Redox Active Molecules on Pt and Au: Selective Reaction of Disulfide with Au.; Uphaus,R. A. Microchem.J.1990,42, 44, and referencestherein on viologen monolayer electrochemistry. (5

  16. Magnetically stimulated fluid flow patterns

    ScienceCinema (OSTI)

    Martin, Jim; Solis, Kyle

    2014-08-06T23:59:59.000Z

    Sandia National Laboratories' Jim Martin and Kyle Solis explain research on the effects of magnetic fields on fluid flows and how they stimulate vigorous flows. Fluid flow is a necessary phenomenon in everything from reactors to cooling engines in cars.

  17. Magnetically stimulated fluid flow patterns

    SciTech Connect (OSTI)

    Martin, Jim; Solis, Kyle

    2014-03-06T23:59:59.000Z

    Sandia National Laboratories' Jim Martin and Kyle Solis explain research on the effects of magnetic fields on fluid flows and how they stimulate vigorous flows. Fluid flow is a necessary phenomenon in everything from reactors to cooling engines in cars.

  18. Sequestration of terrigenous organic carbon on the northern California shelf : role of hyperpycnal flows

    E-Print Network [OSTI]

    Moeremans, Raphaële E.

    2011-01-01T23:59:59.000Z

    cores have not experienced diagenesis from deep burial andwith redox-related diagenesis. Maxima in Fe/Ti ratio could

  19. Fuel cell generator with fuel electrodes that control on-cell fuel reformation

    DOE Patents [OSTI]

    Ruka, Roswell J. (Pittsburgh, PA); Basel, Richard A. (Pittsburgh, PA); Zhang, Gong (Murrysville, PA)

    2011-10-25T23:59:59.000Z

    A fuel cell for a fuel cell generator including a housing including a gas flow path for receiving a fuel from a fuel source and directing the fuel across the fuel cell. The fuel cell includes an elongate member including opposing first and second ends and defining an interior cathode portion and an exterior anode portion. The interior cathode portion includes an electrode in contact with an oxidant flow path. The exterior anode portion includes an electrode in contact with the fuel in the gas flow path. The anode portion includes a catalyst material for effecting fuel reformation along the fuel cell between the opposing ends. A fuel reformation control layer is applied over the catalyst material for reducing a rate of fuel reformation on the fuel cell. The control layer effects a variable reformation rate along the length of the fuel cell.

  20. EXPERIMENTAL INVESTIGATION OF Ti and Fe VALENCE IN CHONDRULE-LIKE MELTS DURING COOLING UNDER CHANGING REDOX CONDITIONS AT LOW PARTIAL PRESSURES. S. B. Simon1

    E-Print Network [OSTI]

    Grossman, Lawrence

    . This idea is being tested experimentally. Initial results were re- ported by [3]; here we report results CHANGING REDOX CONDITIONS AT LOW PARTIAL PRESSURES. S. B. Simon1 , J. R. Beckett2 , S. R. Sutton1,3 and L melted on Fe loops. Three runs are reported here: an isothermal run (I6) at 1400°C for 66 h at 2.75 log

  1. Multi-processor including data flow accelerator module

    DOE Patents [OSTI]

    Davidson, George S. (Albuquerque, NM); Pierce, Paul E. (Albuquerque, NM)

    1990-01-01T23:59:59.000Z

    An accelerator module for a data flow computer includes an intelligent memory. The module is added to a multiprocessor arrangement and uses a shared tagged memory architecture in the data flow computer. The intelligent memory module assigns locations for holding data values in correspondence with arcs leading to a node in a data dependency graph. Each primitive computation is associated with a corresponding memory cell, including a number of slots for operands needed to execute a primitive computation, a primitive identifying pointer, and linking slots for distributing the result of the cell computation to other cells requiring that result as an operand. Circuitry is provided for utilizing tag bits to determine automatically when all operands required by a processor are available and for scheduling the primitive for execution in a queue. Each memory cell of the module may be associated with any of the primitives, and the particular primitive to be executed by the processor associated with the cell is identified by providing an index, such as the cell number for the primitive, to the primitive lookup table of starting addresses. The module thus serves to perform functions previously performed by a number of sections of data flow architectures and coexists with conventional shared memory therein. A multiprocessing system including the module operates in a hybrid mode, wherein the same processing modules are used to perform some processing in a sequential mode, under immediate control of an operating system, while performing other processing in a data flow mode.

  2. Characterization of secondary collection system flows beneath synthetic composite liners

    SciTech Connect (OSTI)

    Groenleer, M.E. [Wenck Associates, Inc., Grand Rapids, MI (United States)

    1995-12-31T23:59:59.000Z

    Secondary liner systems for landfills are becoming more common. Subtitle D may be construed to require secondary liners to meet monitorability requirements for new units. Michigan requires secondary liners in many situations, most commonly at previously contaminated sites to allow for differential monitoring of the new cell(s). Much work has been done in characterizing the flow of liquids through FML/clay composite liners but less is known about flows through FML/geosynthetic clay liner (GCL) composite liners or through isolated FMLs. Flow and chemical data are examined from two Michigan landfills employing different configurations of all synthetic primary and secondary liners. The data is examined for apparent trends. Conclusions are drawn about the application of generic action flow rates as a regulatory standard to these systems and the chemical characteristics of the liquids in secondary systems. Calculations are presented to achieve a realistic action leakage rate for these systems.

  3. Synthesis and charge-transport properties of polymers derived from the oxidation of 1-hydro-1'-(6-(pyrrol-1-yl)hexyl)-4,4'-bipyridium Bis(hexafluorophosphate) and demonstration of pH-sensitive microelectrochemical transistor derived from the redox properties of a conventional redox center

    SciTech Connect (OSTI)

    Shu, C.F.; Wrighton, M.S.

    1988-09-08T23:59:59.000Z

    This article describes the synthesis and electrochemical properties of redox polymers, having a polypyrrole backbone and viologen subunits, derived from oxidative electropolymerization of 1-methyl-1'-(6-(pyrrol-1-yl)hexyl)-4,4'-bipyridinium (P-V-Me/sup 2 +/) and 1-hydro-1'-(6-(pyrrol-1-yl)hexyl)-4,4'-bipyridinium (P-V-H/sup 2 +/). Closely spaced (approx. 1.5 ..mu..M) Au microelectrode arrays (approx. 2.5 ..mu..m wide /times/ 50 ..mu..m long /times/ 0.1 ..mu..m high) modified with the polymers can be used to study aspects of the charge-transport behavior of the viologen redox system. Poly(P-V-Me/sup 2 +/) have been used to investigate the characteristics of microelectrochemical transistors based on a viologen redox center and a similar redox center, protonated, monoquaternized bipyridinium, which is pH dependent. The interesting properties from poly(P-V-Me/sup 2 +/) and poly(P-V-H/sup 2 +/) stem from behavior of the pendant viologen redox centers. The device based on poly(P-V-Me/sup 2 +/) has a narrow region (approx. 200 mV) of gate voltage, V/sub G/, where the source-drain current, I/sub D/, is nonzero and has a sharp, pH-independent peak in the I/sub D/-V/sub G/ plot at approx. 0.53 V versus SCE associated with the reversible, one-electron reduction of viologen. This result is consistent with electron self-exchange between redox centers being the mechanism for charge transport. The device based on poly(P-V-H/sup 2 +/) shows a pH-dependent I/sub D/ at fixed V/sub G/, as expected from the electrochemical behavior from reversible protonation of the terminal N of the bipyridinium group of poly(P-V-H/sup 2 +/). The microelectrochemical transistor based on poly(P-V-H/sup 2 +/) illustrates the design of chemically sensitive, molecule-based devices using conventional redox materials.

  4. Optical flow switching

    E-Print Network [OSTI]

    Chan, Vincent W. S.

    Present-day networks are being challenged by dramatic increases in bandwidth demand of emerging applications. We will explore a new transport, ldquooptical flow switchingrdquo, that will enable significant growth and ...

  5. Olefin Autoxidation in Flow

    E-Print Network [OSTI]

    Neuenschwander, Ulrich

    Handling hazardous multiphase reactions in flow brings not only safety advantages but also significantly improved performance, due to better mass transfer characteristics. In this paper, we present a continuous microreactor ...

  6. The role of nanopores on U(VI) sorption and redox behavior in U(VI)-contaminated subsurface sediments

    SciTech Connect (OSTI)

    Xu, Huifang; Roden, Eric E.; Kemner, Kenneth M.; Jung, Hun-Bok; Konishi, Hiromi; Boyanov, Maxim; Sun, Yubing; Mishra, Bhoopesh

    2013-10-16T23:59:59.000Z

    Most reactive surfaces in clay-dominated sediments are present within nanopores (pores of nm dimension). The behavior of geological fluids and minerals in nanopores is significantly different from those in normal non-nanoporous environments. The effect of nanopore surfaces on U(VI) sorption/desorption and reduction is likely to be significant in clay-rich subsurface environments. Our research results from both model nanopore system and natural sediments from both model system (synthetic nanopore alumina) and sediments from the ORNL Field Research Center prove that U(VI) sorption on nanopore surfaces can be greatly enhanced by nanopore confinement environments. The results from the project provide advanced mechanistic, quantitative information on the physiochemical controls on uranium sorption and redox behavior in subsurface sediments. The influence of nanopore surfaces on coupled uranium sorption/desorption and reduction processes is significant in virtually all subsurface environments, because most reactive surfaces are in fact nanopore surfaces. The results will enhance transfer of our laboratory-based research to a major field research initiative where reductive uranium immobilization is being investigated. Our results will also provide the basic science for developing in-situ colloidal barrier of nanoporous alumina in support of environmental remediation and long term stewardship of DOE sites.

  7. Subsurface microbial community structure correlates with uranium redox phases during in situ field manipulation in a contaminated aquifer

    SciTech Connect (OSTI)

    Kostka, Joel [Florida State University; Green, Stefan [Florida State University, Tallahassee; Wu, Wei-min [Stanford University; Criddle, Craig [Stanford University; Watson, David B [ORNL; Jardine, Philip M [ORNL

    2009-07-01T23:59:59.000Z

    Long-term field manipulation experiments investigating the effects of subsurface redox conditions on the fate and transport of soluble uranium(VI) were conducted over a 3 year period at the Oak Ridge Integrated Field Research Center (OR-IFRC) in Oak Ridge, TN. In the highly contaminated source zone, introduction of ethanol to the subsurface stimulated native denitrifying, sulfate-reducing, iron-reducing and fermentative microorganisms and reduced U to below 0.03 mg/L. Subsequently, oxygen and nitrate were experimentally re-introduced into the subsurface to examine the potential for re-oxidation and re-mobilization of U(IV). Introduction of oxygen or nitrate caused changes in subsurface geochemistry and re-oxidation of U. After reoxidation, the subsurface experienced several months of starvation conditions before ethanol injection was restored to reduce the treatment zone. Subsurface microorganisms were characterized by community fingerprinting, targeted population analyses, and quantitative PCR of key functional groups in 50 samples taken during multiple phases of field manipulation. Statistical analysis confirmed the hypothesis that the microbial community would co-vary with the shifts in the subsurface geochemistry. The level of hydraulic connectivity of sampling wells to the injection well was readily tracked by microbial community analysis. We demonstrate quantitatively that specific populations, especially Desulfosporosinus, are heavily influenced by geochemical conditions and positively correlate with the immobilization of uranium. Following nitrate reoxidation, populations of Fe(II)-oxidizing, nitrate reducing organisms (Thiobacillus) showed an increase in relative abundance.

  8. Electrostatic binding of bicarbonate and formate in viologen-based redox polymers: importance in catalytic reduction of bicarbonate to formate

    SciTech Connect (OSTI)

    Andre, J.F.; Wrighton, M.S.

    1985-12-04T23:59:59.000Z

    The relative importance of electrostatic binding of CO3H and HCO2 in a redox polymer derived from an N,N'-dialkyl-4,4'-bipyridinium monomer has been investigated by Fourier transform infrared (FTIR) spectroscopy. At 298 K and a total concentration of C-containing species of 0.1 M the two species are equally firmly bound in a polymer immobilized on a single-crystal Si electrode surface. When the concentration of C-containing species is 1.0 M, the CO3H ion is more firmly bound by about a factor of 2.5, and at a total concentration of 3.0 M the CO3H ion is about 7 times more firmly bound than the HCO2 ion. The HCO2 and Cl anions are equally firmly bound at 1.0 M total anion concentration. On the basis of the lack of change in the cyclic voltammetry response of a derivatized electrode in 1.0 M Na(CO3H) or Na(HCO2) compared to 1.0 M NaCl, the exchange rate of the C-containing anions does not appear to be a factor that would limit the rate of reduction of the CO3H ion at an electrode modified with the polymer and impregnated with Pd(0).

  9. Photoinduced and redox-induced transmembrane processes with vesicle-stabilized colloidal cadmium sulfide and multicharged viologen derivatives

    SciTech Connect (OSTI)

    Tricot, Y.M.; Porat, Z.; Manassen, J. (Weizmann Inst. of Science, Rehovot (Israel))

    1991-04-18T23:59:59.000Z

    Colloidal cadmium sulfide (CdS) and methylviologen (MV{sup 2+}) or new viologen derivatives carrying more positive charges were placed at specific sites of dihexadecyl phosphate (DHP) vesicles. Benzyl alcohol was used as a sacrificial electron donor to promote reduction of the viologens by photoexcited CdS colloid majority carriers. Transmission electron microscopy, {sup 13}C nuclear magnetic resonance, and differential scanning calorimetry were used for physical characterization. Photochemical events were followed by in situ optical and electrochemical monitoring. Redox-induced transmembrane diffusion, which had been found with MV{sup 2+}, could be reduced by a factor 18 by using a triply charged viologen derivative and by a further factor of 30 in a configuration involving transmembrane electron transfer. In that case the quantum yield was ca. 0.05 at 410 nm, while virtually no reduced viologen leaking could be observed during at least 10 min. Physical evidence was found for a partial penetration of the CdS colloids into the DHP membrane.

  10. Photoinduced redox reactions in aqueous micelles. Quenching, back-reaction, and competing processes for tetraanionic porphyrins with alkylviologens

    SciTech Connect (OSTI)

    Schmehl, R.H.; Whitten, D.G.

    1981-11-12T23:59:59.000Z

    Photoinduced redox reactions employing the anionic porphyrins meso-tetrakis(p-sulfonatophenyl)porphyrin (1) and its palladium(II) complex (2) as excited substrates and various alkylviologens as quenchers have been studied in homogeneous aqueous solution and in the presence of the charged detergents sodium dodecyl sulfate (SDS) and cetyltrimethylammonium chloride (CTAC) above the critical micelle concentration (cmc). In homogeneous solution strong ground-state association between the porphyrins and the viologens occurs; even dynamic quenching processes result in no separation of electron transfer product ions. Addition of either SDS or CTAC reduces the quenching rates but allows the detection of product ions surviving up to ca. 100 ms in some cases. The back-reactions are sensitive to a variety of factors including added electrolyte, hydrophobicity of the viologen and its one-electron reduction product, and the charge on the surfactant. The long-lived products can be selectively intercepted by a variety of reagents. In the case of quenching of the palladium porphyrin (2) by methylviologen, the oxidized porphyrin can be reduced by iodide while the reduced viologen can be oxidized via either a colloidal catalyst or reaction with molecular oxygen. These reactions illustrate the possibility for obtaining net chemical conversion in a process whereby both the light-absorbing substrate and the quencher are recycled.

  11. Conjugate flow action functionals

    SciTech Connect (OSTI)

    Venturi, Daniele, E-mail: daniele-venturi@brown.edu [Division of Applied Mathematics, Brown University, Rhode Island 02912 (United States)] [Division of Applied Mathematics, Brown University, Rhode Island 02912 (United States)

    2013-11-15T23:59:59.000Z

    We present a new general framework to construct an action functional for a non-potential field theory. The key idea relies on representing the governing equations relative to a diffeomorphic flow of curvilinear coordinates which is assumed to be functionally dependent on the solution field. Such flow, which will be called the conjugate flow, evolves in space and time similarly to a physical fluid flow of classical mechanics and it can be selected in order to symmetrize the Gâteaux derivative of the field equations with respect to suitable local bilinear forms. This is equivalent to requiring that the governing equations of the field theory can be derived from a principle of stationary action on a Lie group manifold. By using a general operator framework, we obtain the determining equations of such manifold and the corresponding conjugate flow action functional. In particular, we study scalar and vector field theories governed by second-order nonlinear partial differential equations. The identification of transformation groups leaving the conjugate flow action functional invariant could lead to the discovery of new conservation laws in fluid dynamics and other disciplines.

  12. SOFC seal and cell thermal management

    DOE Patents [OSTI]

    Potnis, Shailesh Vijay (Neenah, WI); Rehg, Timothy Joseph (Huntington Beach, CA)

    2011-05-17T23:59:59.000Z

    The solid oxide fuel cell module includes a manifold, a plate, a cathode electrode, a fuel cell and an anode electrode. The manifold includes an air or oxygen inlet in communication with divergent passages above the periphery of the cell which combine to flow the air or oxygen radially or inwardly for reception in the center of the cathode flow field. The latter has interconnects providing circuitous cooling passages in a generally radial outward direction cooling the fuel cell and which interconnects are formed of different thermal conductivity materials for a preferential cooling.

  13. Section 13: Flow control 1 Section 13: Flow control

    E-Print Network [OSTI]

    Kohlenbach, Ulrich

    Geometries for Energyefficient Flow Around Bodies Abstract 14:30 ­ 14:50: Elfriede Friedmann (Universität

  14. [Unsegmented continuous-flow sample processing and electrochemical detection of gaseous species

    SciTech Connect (OSTI)

    Mottola, H.A.

    1991-01-01T23:59:59.000Z

    Goals were a continuous-flow, unsegmented, all-gas carrier and/or a segmented liquid/gas interface system for sample introduction and transport to detection/determination point; a regenerable electrode probe base on redox reactions of Fe(II) and Fe(III) complexes with 1, 10-phenanthroline and related ligands; and amperometric/coulometric current measurements providing analyte signals. Gases to be detected included NO[sub x] and SO[sub 2]. This report is divided into 3 parts: preparation of new ligands of 1,10-phenanthroline family; glassy carbon surfaces coated with polymeric films prepared from monomeric units of tris[5-amino-1,10-phenanthroline]iron(II); and sulfite oxidase/hexacyanoferrate modified C paste electrode.

  15. Filtration and Leach Testing for REDOX Sludge and S-Saltcake Actual Waste Sample Composites

    SciTech Connect (OSTI)

    Shimskey, Rick W.; Billing, Justin M.; Buck, Edgar C.; Daniel, Richard C.; Draper, Kathryn E.; Edwards, Matthew K.; Geeting, John GH; Hallen, Richard T.; Jenson, Evan D.; Kozelisky, Anne E.; MacFarlan, Paul J.; Peterson, Reid A.; Snow, Lanee A.; Swoboda, Robert G.

    2009-02-20T23:59:59.000Z

    A testing program evaluating actual tank waste was developed in response to Task 4 from the M-12 External Flowsheet Review Team (EFRT) issue response plan.( ) The test program was subdivided into logical increments. The bulk water-insoluble solid wastes that are anticipated to be delivered to the Waste Treatment and Immobilization Plant (WTP) were identified according to type such that the actual waste testing could be targeted to the relevant categories. Under test plan TP-RPP-WTP-467, eight broad waste groupings were defined. Samples available from the 222S archive were identified and obtained for testing. Under this test plan, a waste-testing program was implemented that included: • Homogenizing the archive samples by group as defined in the test plan • Characterizing the homogenized sample groups • Performing parametric leaching testing on each group for compounds of interest • Performing bench-top filtration/leaching tests in the hot cell for each group to simulate filtration and leaching activities if they occurred in the UFP2 vessel of the WTP Pretreatment Facility. This report focuses on filtration/leaching tests performed on two of the eight waste composite samples and follow-on parametric tests to support aluminum leaching results from those tests.

  16. Energy Flow Energy Flow Energy Flow A.Ukleja, T.Tymieniecka, I.Skillicorn 1 Azimuthal asymmetry

    E-Print Network [OSTI]

    Energy Flow Energy Flow Energy Flow A.Ukleja, T.Tymieniecka, I.Skillicorn 1 Azimuthal asymmetry using energy flow method Azimuthal angle distribution at Q2 >100 GeV2 Energy flow method.Ukleja on behalf of the ZEUS Collaboration #12; Energy Flow Energy Flow Energy Flow A.Ukleja, T.Tymieniecka, I

  17. Friction and the oscillatory motion of granular flows

    E-Print Network [OSTI]

    Lydie Staron

    2012-11-26T23:59:59.000Z

    This contribution reports on numerical simulations of 2D granular flows on erodible beds. The broad aim is to investigate whether simple flows of model granular matter exhibits spontaneous oscillatory motion in generic flow conditions, and in this case, whether the frictional properties of the contacts between grains may affect the existence or the characteristics of this oscillatory motion. The analysis of different series of simulations show that the flow develops an oscillatory motion with a well-defined frequency which increases like the inverse of the velocity's square root. We show that the oscillation is essentially a surface phenomena. The amplitude of the oscillation is higher for lower volume fractions, and can thus be related to the flow velocity and grains friction properties. The study of the influence of the periodic geometry of the simulation cell shows no significant effect. These results are discussed in relation to sonic sands.

  18. In situ PEM fuel cell water measurements

    SciTech Connect (OSTI)

    Borup, Rodney L [Los Alamos National Laboratory; Mukundan, Rangachary [Los Alamos National Laboratory; Davey, John R [Los Alamos National Laboratory; Spendelow, Jacob S [Los Alamos National Laboratory; Hussey, Daniel S [NIST; Jacobson, David L [NIST; Arif, Muhammad [NIST

    2009-01-01T23:59:59.000Z

    Efficient PEM (Polymer Electrolyte Membrane) fuel cell performance requires effective water management. To achieve a deeper understanding of water transport and performance issues associated with water management, we have conducted in situ water examinations to help understand the effects of components and operations. High Frequency Resistance (HFR), AC Impedance and Neutron imaging were used to measure water content in operating fuel cells, with various conditions, including current density, relative humidity, inlet flows, flow orientation and variable Gas Diffusion Layer (GDL) properties. High resolution neutron radiography was used to image fuel cells during a variety of conditions. The effect of specific operating conditions, including flow direction (co-flow or counter-flow) was examined. Counter-flow operation was found to result in higher water content than co-flow operation, which correlates to lower membrane resistivity. A variety of cells were used to quantify the membrane water in situ during exposure to saturated gases, during fuel cell operation, and during hydrogen pump operation. The quantitative results show lower membrane water content than previous results suggested.

  19. Corrosion test cell for bipolar plates

    DOE Patents [OSTI]

    Weisbrod, Kirk R. (Los Alamos, NM)

    2002-01-01T23:59:59.000Z

    A corrosion test cell for evaluating corrosion resistance in fuel cell bipolar plates is described. The cell has a transparent or translucent cell body having a pair of identical cell body members that seal against opposite sides of a bipolar plate. The cell includes an anode chamber and an cathode chamber, each on opposite sides of the plate. Each chamber contains a pair of mesh platinum current collectors and a catalyst layer pressed between current collectors and the plate. Each chamber is filled with an electrolyte solution that is replenished with fluid from a much larger electrolyte reservoir. The cell includes gas inlets to each chamber for hydrogen gas and air. As the gases flow into a chamber, they pass along the platinum mesh, through the catalyst layer, and to the bipolar plate. The gas exits the chamber through passageways that provide fluid communication between the anode and cathode chambers and the reservoir, and exits the test cell through an exit port in the reservoir. The flow of gas into the cell produces a constant flow of fresh electrolyte into each chamber. Openings in each cell body is member allow electrodes to enter the cell body and contact the electrolyte in the reservoir therein. During operation, while hydrogen gas is passed into one chamber and air into the other chamber, the cell resistance is measured, which is used to evaluate the corrosion properties of the bipolar plate.

  20. Fuel cell repeater unit including frame and separator plate

    DOE Patents [OSTI]

    Yamanis, Jean; Hawkes, Justin R; Chiapetta, Jr., Louis; Bird, Connie E; Sun, Ellen Y; Croteau, Paul F

    2013-11-05T23:59:59.000Z

    An example fuel cell repeater includes a separator plate and a frame establishing at least a portion of a flow path that is operative to communicate fuel to or from at least one fuel cell held by the frame relative to the separator plate. The flow path has a perimeter and any fuel within the perimeter flow across the at least one fuel cell in a first direction. The separator plate, the frame, or both establish at least one conduit positioned outside the flow path perimeter. The conduit is outside of the flow path perimeter and is configured to direct flow in a second, different direction. The conduit is fluidly coupled with the flow path.

  1. Time-resolved fluorescence decay measurements for flowing particles

    DOE Patents [OSTI]

    Deka, C.; Steinkamp, J.A.

    1999-06-01T23:59:59.000Z

    Time-resolved fluorescence decay measurements are disclosed for flowing particles. An apparatus and method for the measurement and analysis of fluorescence for individual cells and particles in flow are described, wherein the rapid measurement capabilities of flow cytometry and the robust measurement and analysis procedures of time-domain fluorescence lifetime spectroscopy are combined. A pulse-modulated CW laser is employed for excitation of the particles. The characteristics and the repetition rate of the excitation pulses can be readily adjusted to accommodate for fluorescence decays having a wide range of lifetimes. 12 figs.

  2. Fuel cell stack arrangements

    DOE Patents [OSTI]

    Kothmann, Richard E. (Churchill Boro, PA); Somers, Edward V. (Murrysville, PA)

    1982-01-01T23:59:59.000Z

    Arrangements of stacks of fuel cells and ducts, for fuel cells operating with separate fuel, oxidant and coolant streams. An even number of stacks are arranged generally end-to-end in a loop. Ducts located at the juncture of consecutive stacks of the loop feed oxidant or fuel to or from the two consecutive stacks, each individual duct communicating with two stacks. A coolant fluid flows from outside the loop, into and through cooling channels of the stack, and is discharged into an enclosure duct formed within the loop by the stacks and seals at the junctures at the stacks.

  3. Fuel cell system combustor

    DOE Patents [OSTI]

    Pettit, William Henry (Rochester, NY)

    2001-01-01T23:59:59.000Z

    A fuel cell system including a fuel reformer heated by a catalytic combustor fired by anode and cathode effluents. The combustor includes a turbulator section at its input end for intimately mixing the anode and cathode effluents before they contact the combustors primary catalyst bed. The turbulator comprises at least one porous bed of mixing media that provides a tortuous path therethrough for creating turbulent flow and intimate mixing of the anode and cathode effluents therein.

  4. Single-layer planar on-chip flow cytometer using microfluidic drifting based three-dimensional (3D) hydrodynamic focusing

    E-Print Network [OSTI]

    cytometry, this can be achieved by focusing the cell solution at the centre of the flow tube horizontal (parallel to the device plane) sheath flows. One may readily fabricate the device for 2DSingle-layer planar on-chip flow cytometer using microfluidic drifting based three-dimensional (3D

  5. A VLSI Design Flow for Secure Side-Channel Attack Resistant ICs and Ingrid Verbauwhede1,2

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    A VLSI Design Flow for Secure Side-Channel Attack Resistant ICs Kris Tiri1 and Ingrid Verbauwhede1 VLSI design flow to create secure, side-channel attack (SCA) resistant integrated circuits. The design standard cell design flow. We discuss the basis for side-channel attack resistance and adjust the library

  6. Generator configuration for solid oxide fuel cells

    DOE Patents [OSTI]

    Reichner, Philip (Plum Boro, PA)

    1989-01-01T23:59:59.000Z

    Disclosed are improvements in a solid oxide fuel cell generator 1 having a multiplicity of electrically connected solid oxide fuel cells 2, where a fuel gas is passed over one side of said cells and an oxygen-containing gas is passed over the other side of said cells resulting in the generation of heat and electricity. The improvements comprise arranging the cells in the configuration of a circle, a spiral, or folded rows within a cylindrical generator, and modifying the flow rate, oxygen concentration, and/or temperature of the oxygen-containing gases that flow to those cells that are at the periphery of the generator relative to those cells that are at the center of the generator. In these ways, a more uniform temperature is obtained throughout the generator.

  7. Gaseous Flows in Galaxies

    E-Print Network [OSTI]

    F. Combes

    2007-09-02T23:59:59.000Z

    The gas component plays a major role in the dynamics of spiral galaxies, because of its dissipative character, and its ability to exchange angular momentum with stars in the disk. Due to its small velocity dispersion, it triggers gravitational instabilities, and the corresponding non-axisymmetric patterns produce gravity torques, which mediate these angular momentum exchanges. When a srong bar pattern develops with the same pattern speed all over the disk, only gas inside corotation can flow towards the center. But strong bars are not long lived in presence of gas, and multiple-speed spiral patterns can develop between bar phases, and help the galaxy to accrete external gas flowing from cosmic filaments. The gas is then intermittently driven to the galaxy center, to form nuclear starbursts and fuel an active nucleus. The various time-scales of these gaseous flows are described.

  8. Variable area fuel cell cooling

    DOE Patents [OSTI]

    Kothmann, Richard E. (Churchill Borough, PA)

    1982-01-01T23:59:59.000Z

    A fuel cell arrangement having cooling fluid flow passages which vary in surface area from the inlet to the outlet of the passages. A smaller surface area is provided at the passage inlet, which increases toward the passage outlet, so as to provide more uniform cooling of the entire fuel cell. The cooling passages can also be spaced from one another in an uneven fashion.

  9. Multiphase cooling flows

    E-Print Network [OSTI]

    Peter A. Thomas

    1996-08-20T23:59:59.000Z

    I discuss the multiphase nature of the intracluster medium whose neglect can lead to overestimates of the baryon fraction of clusters by up to a factor of two. The multiphase form of the cooling flow equations are derived and reduced to a simple form for a wide class of self-similar density distributions. It is shown that steady-state cooling flows are \\emph{not} consistent with all possible emissivity profiles which can therefore be used as a test of the theory. In combination, they provide strong constraints on the mass distribution within the cooling radius.

  10. Viologen (2+/1+) and viologen(1+/0) electron-self-exchange reactions in a redox polymer

    SciTech Connect (OSTI)

    Dalton, E.F.; Murray, R.W. (Univ. of North Carolina, Chapel Hill (United States))

    1991-08-08T23:59:59.000Z

    An analysis is given of the electron-self-exchange reactions responsible for the steady-state redox conductivity of thin films of the electropolymerized monomer N,N{prime}-bis(3-pyrrol-1-yl-propyl)-4,4{prime}-bipyridinium tetrafluoroborate, sandwiched between two electrodes. Concentration-gradient-driven electron self-exchange in the liquid-acetonitrile-bathed viologen(2+/1+) mixed-valent state of this polymer, k{sub ex} = 8 {times} 10{sup 3} M{sup {minus}1}s{sup {minus}1}, is much slower than that for the viologen (1+/0) mixed-valent state, k{sub ek} = 1.6 {times} 10{sup 5} M{sup {minus}1} s{sup {minus}1}, which has a smaller activation barrier. Neither self-exchange reaction responds to use of alternative counteranions except that both rates decrease in polymer containing tosylate counterions. The rate constant found for the electrical-gradient-driven viologen (1+/0) electron self-exchange, k{sub ex} = 1.1 {times} 10{sup 5} M{sup {minus}1} s{sup {minus}1}, observed in dry, N{sub 2}-bathed polymer where ClO{sub 4}{sup {minus}} counterion mobility is quenched, is nearly the same as the acetonitrile-bathed value. The rate constants appear to be dominated by characteristics of the polymer phase rather than the bathing environment of the polymer. Estimates are made of the counteranion diffusivity in acetonitrile-bathed films and of how it effects transient electron transport measurements.

  11. Redox Exchange Induced MnO2 Nanoparticle Enrichment in Poly(3,4-ethylenedioxythiophene) Nanowires for Electrochemical Energy Storage

    SciTech Connect (OSTI)

    Liu, R; Duay, Jonathon; Lee, Sang Bok

    2010-01-01T23:59:59.000Z

    MnO{sub 2} nanoparticle enriched poly(3,4-ethylenedioxythiophene) (PEDOT) nanowires are fabricated by simply soaking the PEDOT nanowires in potassium permanganate (KMnO{sub 4}) solution. The structures of these MnO{sub 2} nanoparticle enriched PEDOT nanowires are characterized by SEM and TEM, which show that the MnO{sub 2} nanoparticles have uniform sizes and are finely dispersed in the PEDOT matrix. The chemical constituents and bonding of these composite nanowires are characterized by energy-dispersive X-ray analysis, X-ray photoelectron spectroscopy, and infrared spectroscopy, which indicate that the formation and dispersion of these MnO{sub 2} nanoparticles into the nanoscale pores of the PEDOT nanowires are most likely triggered by the reduction of KMnO{sub 4} via the redox exchange of permanganate ions with the functional group on PEDOT. Varying the concentrations of KMnO{sub 4} and the reaction time controls the loading amount and size of the MnO{sub 2} nanoparticles. Cyclic voltammetry and galvanostatic charge?discharge are used to characterize the electrochemical properties of these MnO{sub 2} nanoparticle loaded PEDOT nanowires. Due to their extremely high exposed surface area with nanosizes, the pristine MnO{sub 2} nanoparticles in these MnO{sub 2} nanoparticle enriched PEDOT nanowires show very high specific capacitance (410 F/g) as the supercapacitor electrode materials as well as high Li+ storage capacity (300 mAh/g) as cathode materials of Li ion battery, which boost the energy storage capacity of PEDOT nanowires to 4 times without causing excessive volume expansion in the polymer. The highly conductive and porous PEDOT matrix facilitates fast charge/discharge of the MnO{sub 2} nanoparticles and prevents them from agglomerating. These synergic properties enable the MnO{sub 2} nanoparticle enriched PEDOT nanowires to be promising electrode materials for supercapacitors and lithium ion batteries.

  12. Fuel Cells for Transportation FY 2001 Progress Report V. PEM STACK COMPONENT COST REDUCTION1

    E-Print Network [OSTI]

    and flow field. - Optimize the fuel cell flow field design for optimized water management and air bleedFuel Cells for Transportation FY 2001 Progress Report 113 V. PEM STACK COMPONENT COST REDUCTION1 A. High-Performance, Matching PEM Fuel Cell Components and Integrated Pilot Manufacturing Processes Mark K

  13. Spectroscopic Investigations of the Fouling Process on Nafion...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Redox Flow Batteries. Abstract: The Nafion-117 membrane used in vanadium redox flow battery (VRFB) is analyzed by X-ray photoelectron spectroscopy (XPS) and nuclear magnetic...

  14. Detecting multiple cell-secreted cytokines from the same aptamer-functionalized electrode

    E-Print Network [OSTI]

    Ferrara, Katherine W.

    with anthraquinone (AQ) and methylene blue (MB) redox reporters respectively. Random immobilization of two aptamer

  15. Hematopoietic Stem Cells Differentiate Through A Multipotent Progenitor Before Generating All Mature Hematopoietic Cells

    E-Print Network [OSTI]

    Boyer, Scott Wilson

    2013-01-01T23:59:59.000Z

    FlowJo analysis software (Ashland, OR). Cell populationsJose, CA). Flowjo Software (Ashland, OR) was used for dataJose, CA). Flowjo Software (Ashland, OR) was used for data

  16. AGN and Cooling Flows

    E-Print Network [OSTI]

    James Binney

    2001-03-23T23:59:59.000Z

    For two decades the steady-state cooling-flow model has dominated the literature of cluster and elliptical-galaxy X-ray sources. For ten years this model has been in severe difficulty from a theoretical point of view, and it is now coming under increasing pressure observationally. For two decades the steady-state cooling-flow model has dominated the literature of cluster and elliptical-galaxy X-ray sources. For ten years this model has been in severe difficulty from a theoretical point of view, and it is now coming under increasing pressure observationally. A small number of enthusiasts have argued for a radically different interpretation of the data, but had little impact on prevailing opinion because the unsteady heating picture that they advocate is extremely hard to work out in detail. Here I explain why it is difficult to extract robust observational predictions from the heating picture. Major problems include the variability of the sources, the different ways in which a bi-polar flow can impact on X-ray emission, the weakness of synchrotron emission from sub-relativistic flows, and the sensitivity of synchrotron emission to a magnetic field that is probably highly localized.

  17. Flow-controlled magnetic particle manipulation

    DOE Patents [OSTI]

    Grate, Jay W [West Richland, WA; Bruckner-Lea, Cynthia J [Richland, WA; Holman, David A [Las Vegas, NV

    2011-02-22T23:59:59.000Z

    Inventive methods and apparatus are useful for collecting magnetic materials in one or more magnetic fields and resuspending the particles into a dispersion medium, and optionally repeating collection/resuspension one or more times in the same or a different medium, by controlling the direction and rate of fluid flow through a fluid flow path. The methods provide for contacting derivatized particles with test samples and reagents, removal of excess reagent, washing of magnetic material, and resuspension for analysis, among other uses. The methods are applicable to a wide variety of chemical and biological materials that are susceptible to magnetic labeling, including, for example, cells, viruses, oligonucleotides, proteins, hormones, receptor-ligand complexes, environmental contaminants and the like.

  18. Characterization of illuminated semiconductor/solid-electrolyte junctions. photoelectrochemical investigation of a poly(ethylene oxide) cell. Interim technical report 1 Mar-30 Apr 83

    SciTech Connect (OSTI)

    Sammells, A.F.; Ang, P.G.P.

    1983-05-01T23:59:59.000Z

    Photoelectrochemical effects have been observed with solid-state cells using a poly(ethylene oxide) .NaSCN solid polymer electrolyte containing a Na2S/S redox couple. Photoeffects were observed at the interface of this electrolyte with p-InP, n-GaAs, and in a two-photoelectrode cell of configuration p-InP/PEO-NaSCN, Na2S,S/n-CdS. In this latter cell, photopotentials of 540 mV were generated using 100 mW/cm2 quartz iodine illumination.

  19. Brazed bipolar plates for PEM fuel cells

    DOE Patents [OSTI]

    Neutzler, J.K.

    1998-07-07T23:59:59.000Z

    A liquid-cooled, bipolar plate separating adjacent cells of a PEM fuel cell comprises corrosion-resistant metal sheets brazed together so as to provide a passage between the sheets through which a dielectric coolant flows. The brazement comprises a metal which is substantially insoluble in the coolant. 6 figs.

  20. ASIAN SYMPOSIUM ON VISUALIZATION, 2003 Visualizing Heterogeneous Flows in Micro Fluidic Devices

    E-Print Network [OSTI]

    Cubaud, Thomas

    with interesting practical applications in enhanced oil recovery, heat pipes, and micro methanol fuel cells. Gas. Visualizing two-phase flow The transport of gas bubbles in polygonal microchannels is a hydrodynamic problem

  1. Original article Flow and passage rate studies at the ileal level in the

    E-Print Network [OSTI]

    Boyer, Edmond

    based mainly on lucerne meal. Flow and transit measurements were carried out using two particulate markers : ytterbium (Yb) fixed on lucerne meal cell-walls by soaking, and chromium (Cr) fixed

  2. Aqueous Transition Metal Cations as Impurities in a Wide Gap Oxide: The Cu^2+/Cu^1+ and Ag^2+/Ag^1+ Redox Couples Revisited

    E-Print Network [OSTI]

    Liu, Xiandong; Cheng, Jun; Sprik, Michiel

    2014-11-11T23:59:59.000Z

    of 10ps. The longitudinal relaxation is more than a magnitude faster. Results and analysis Gas-phase Table 1 lists the calculated M-O bond lengths in the four gas-phase complexes we have investigated (see fig. 1). One can see that for the same number... containing a fraction of Hartree-Fock exchange. These calculations make use of recent progress in DFTMD technology enabling us to include sp core polarization and Hartree-Fock exchange in condensed phase model systems. Keywords Aqueous redox chemistry...

  3. Coupling free flow / porous-medium flow General idea

    E-Print Network [OSTI]

    Cirpka, Olaf Arie

    equation t (v) + div (vv ) - div(v) + p - g - qv = 0 Darcy flow equation t (S) - div K (p - g) - qpmT transport equation t (X) + div (vX - DsteamX) = qsteam 16/14 #12;Backup additional Darcy flow equations-Stokes 1 phase, 2 components, temperature sharp interface porous-medium / Darcy flow 2 phases, 2 component

  4. Microscale gas flow: A comparison of Grad's 13 moment equations and other continuum approaches

    E-Print Network [OSTI]

    Victoria, University of

    Microscale gas flow: A comparison of Grad's 13 moment equations and other continuum approaches are being manufactured in quantity [2][3], e.g., pumps, turbines, valves and nozzles. These devices and chemical sensors, and fuel cells. The gas and fluid flows in devices of this size exhibit behavior that can

  5. Message Flow Modulator Final Report

    E-Print Network [OSTI]

    Boyer, Robert Stephen

    operational environment at the Patuxent River Naval Air Test Center with scenarios developed by an independent in testing and demonstrating the flow modulator at the Patuxent River Naval Air Test Center. #12;MESSAGE FLOW

  6. Radial flow pulse jet mixer

    DOE Patents [OSTI]

    VanOsdol, John G.

    2013-06-25T23:59:59.000Z

    The disclosure provides a pulse jet mixing vessel for mixing a plurality of solid particles. The pulse jet mixing vessel is comprised of a sludge basin, a flow surface surrounding the sludge basin, and a downcoming flow annulus between the flow surface and an inner shroud. The pulse jet mixing vessel is additionally comprised of an upper vessel pressurization volume in fluid communication with the downcoming flow annulus, and an inner shroud surge volume separated from the downcoming flow annulus by the inner shroud. When the solid particles are resting on the sludge basin and a fluid such as water is atop the particles and extending into the downcoming flow annulus and the inner shroud surge volume, mixing occurs by pressurization of the upper vessel pressurization volume, generating an inward radial flow over the flow surface and an upwash jet at the center of the sludge basin.

  7. Flow (2008) Director: Irena Salina

    E-Print Network [OSTI]

    Hemmers, Oliver

    2008-01-01T23:59:59.000Z

    Flow (2008) Director: Irena Salina Run Time: 93 min. Summary: ,Irena Salina's documentary film://documentaryfilms.suite101.com/article.cfm/desperate_for_water_irena_salinas_movie_flow No Dumb Questions (2001) Director

  8. Solid oxide fuel cell generator

    DOE Patents [OSTI]

    Draper, R.; George, R.A.; Shockling, L.A.

    1993-04-06T23:59:59.000Z

    A solid oxide fuel cell generator has a pair of spaced apart tubesheets in a housing. At least two intermediate barrier walls are between the tubesheets and define a generator chamber between two intermediate buffer chambers. An array of fuel cells have tubes with open ends engaging the tubesheets. Tubular, axially elongated electrochemical cells are supported on the tubes in the generator chamber. Fuel gas and oxidant gas are preheated in the intermediate chambers by the gases flowing on the other side of the tubes. Gas leakage around the tubes through the tubesheets is permitted. The buffer chambers reentrain the leaked fuel gas for reintroduction to the generator chamber.

  9. Solid oxide fuel cell generator

    DOE Patents [OSTI]

    Draper, Robert (Churchill Boro, PA); George, Raymond A. (Pittsburgh, PA); Shockling, Larry A. (Plum Borough, PA)

    1993-01-01T23:59:59.000Z

    A solid oxide fuel cell generator has a pair of spaced apart tubesheets in a housing. At least two intermediate barrier walls are between the tubesheets and define a generator chamber between two intermediate buffer chambers. An array of fuel cells have tubes with open ends engaging the tubesheets. Tubular, axially elongated electrochemical cells are supported on the tubes in the generator chamber. Fuel gas and oxidant gas are preheated in the intermediate chambers by the gases flowing on the other side of the tubes. Gas leakage around the tubes through the tubesheets is permitted. The buffer chambers reentrain the leaked fuel gas for reintroduction to the generator chamber.

  10. Ricci flow and quantum theory

    E-Print Network [OSTI]

    Robert Carroll

    2007-11-05T23:59:59.000Z

    We show some relations between Ricci flow and quantum theory via Fisher information and the quantum potential.

  11. Viscoelastic transient of confined Red Blood Cells

    E-Print Network [OSTI]

    Gaël Prado; Alexander Farutin; Chaouqi Misbah; Lionel Bureau

    2014-09-17T23:59:59.000Z

    The unique ability of a red blood cell to flow through extremely small microcapillaries depends on the viscoelastic properties of its membrane. Here, we study in vitro the response time upon flow startup exhibited by red blood cells confined into microchannels. We show that the characteristic transient time depends on the imposed flow strength, and that such a dependence gives access to both the effective viscosity and the elastic modulus controlling the temporal response of red cells. A simple theoretical analysis of our experimental data, validated by numerical simulations, further allows us to compute an estimate for the two-dimensional membrane viscosity of red blood cells, $\\eta_{mem}^{2D}\\sim 10^{-7}$ N$\\cdot$s$\\cdot$m$^{-1}$. By comparing our results with those from previous studies, we discuss and clarify the origin of the discrepancies found in the literature regarding the determination of $\\eta_{mem}^{2D}$, and reconcile seemingly conflicting conclusions from previous works.

  12. Poly(pyridine)ruthenium(II)-photoinduced redox reactions of bipyridinium cations, poly(pyridine)rhodium complexes, and osmium ammines

    SciTech Connect (OSTI)

    Creutz, C.; Keller, A.D.; Sutin, N.; Zipp, A.P.

    1982-06-30T23:59:59.000Z

    The quenching of *RuL/sub 3//sup 2 +/ (L is a 2,2'-bipyridine or 1,10-phenanthroline derivative) emissions by three classes of oxidants Q has been examined. The results are discussed in terms of the Marcus electron-transfer model recast in a preequilibrium formalism. Substituted bipyridinium cations (methyl viologen and related compounds) undergo thermodynamically favorable reduction with a driving force ranging from 0.1 to 0.7 eV and rate constants in the range (0.4-2.0) x 10/sup 9/ M/sup -1/s/sup -1/, consistent with a diffusion rate constant of 2.0 x 10/sup 9/ M/sup -1/s/sup -1/ and an exchange rate constant of approx.10/sup 6/ M/sup -1/s/sup -1/ for the Q-Q couples. The yields of the separated redox products RuL/sub 3//sup 3 +/ and Q/sup -/ (typically 0.1 mol einstein/sup -1/ per quenching act) require K/sub 30/, the ''intramolecular'' back-reaction rate constant (to re-form ground-state RuL/sub 3//sup 2 +/ and Q), to be (2-4) x 10/sup 10/ s/sup -1/. Since K/sub 30/ increases weakly with driving force in this series, there is no evidence for inverted behavior despite the fact the ..delta..G/sup 0//sub 30/ is approx.-2 eV. With Q = Rh(4,4'-(CH/sub 3/)/sub 2/bpy)/sub 3//sup 3 +/, the quenching rate constants, k/sub q/ = (0.001-1.0) x 10/sup 9/ M/sup -1/s/sup -1/, exhibit a great sensitivity to the reducing power of *RuL/sub 3//sup 2 +/ and have been fitted to k/sub 11/ approx. = 2 x 10/sup 9/ M/sup -1/s/sup -1/ and E/sup 0//sub Q,Q/sup -// = -0.97 V for the RhL/sub 3//sup 3 +/-RhL/sub 3//sup 2 +/ couple. This E/sup 0/ value is strikingly similar to that (-0.9 V vs. aqueous SCE) obtained via cyclic voltammetry in acetonitrile. The cyclic voltammetry of the RhL/sub 3//sup 3 +/ complexes in water has been reexamined, and it is concluded that the irreversibility observed is due to ligand loss from rhodium(I).

  13. Fuel Cells

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Fuel Cells Converting chemical energy of hydrogenated fuels into electricity Project Description Invented in 1839, fuels cells powered the Gemini and Apollo space missions, as well...

  14. The Big Flow

    E-Print Network [OSTI]

    P. Sikivie

    2001-12-04T23:59:59.000Z

    The late infall of cold dark matter onto an isolated galaxy, such as our own, produces streams and caustics in its halo. The outer caustics are topological spheres whereas the inner caustics are rings. The self-similar model of galactic halo formation predicts that the caustic ring radii $a_n$ follow the approximate law $a_n \\sim 1/n$. In a study of 32 extended and well-measured external galactic rotation curves evidence was found for this law. In the case of the Milky Way, the locations of eight sharp rises in the rotation curve fit the prediction of the self-similar model at the 3% level. Moreover, a triangular feature in the IRAS map of the galactic plane is consistent with the imprint of a ring caustic upon the baryonic matter. These observations imply that the dark matter in our neighborhood is dominated by a single flow. Estimates of that flow's density and velocity vector are given.

  15. Structural power flow measurement

    SciTech Connect (OSTI)

    Falter, K.J.; Keltie, R.F.

    1988-12-01T23:59:59.000Z

    Previous investigations of structural power flow through beam-like structures resulted in some unexplained anomalies in the calculated data. In order to develop structural power flow measurement as a viable technique for machine tool design, the causes of these anomalies needed to be found. Once found, techniques for eliminating the errors could be developed. Error sources were found in the experimental apparatus itself as well as in the instrumentation. Although flexural waves are the carriers of power in the experimental apparatus, at some frequencies longitudinal waves were excited which were picked up by the accelerometers and altered power measurements. Errors were found in the phase and gain response of the sensors and amplifiers used for measurement. A transfer function correction technique was employed to compensate for these instrumentation errors.

  16. Convective heat flow probe

    DOE Patents [OSTI]

    Dunn, J.C.; Hardee, H.C.; Striker, R.P.

    1984-01-09T23:59:59.000Z

    A convective heat flow probe device is provided which measures heat flow and fluid flow magnitude in the formation surrounding a borehole. The probe comprises an elongate housing adapted to be lowered down into the borehole; a plurality of heaters extending along the probe for heating the formation surrounding the borehole; a plurality of temperature sensors arranged around the periphery of the probe for measuring the temperature of the surrounding formation after heating thereof by the heater elements. The temperature sensors and heater elements are mounted in a plurality of separate heater pads which are supported by the housing and which are adapted to be radially expanded into firm engagement with the walls of the borehole. The heat supplied by the heater elements and the temperatures measured by the temperature sensors are monitored and used in providing the desired measurements. The outer peripheral surfaces of the heater pads are configured as segments of a cylinder and form a full cylinder when taken together. A plurality of temperature sensors are located on each pad so as to extend along the length and across the width thereof, with a heating element being located in each pad beneath the temperature sensors. An expansion mechanism driven by a clamping motor provides expansion and retraction of the heater pads and expandable packet-type seals are provided along the probe above and below the heater pads.

  17. Cell Stem Cell Clinical Progress

    E-Print Network [OSTI]

    Zandstra, Peter W.

    Cell Stem Cell Clinical Progress Rapid Expansion of Human Hematopoietic Stem Cells by Automated of Toronto, Toronto, ON M5G 1L7, Canada 6McEwen Centre for Regenerative Medicine, University Health Network

  18. Relation between photospheric flow fields and the magnetic field distribution on the solar surface

    SciTech Connect (OSTI)

    Simon, G.W.; Title, A.M.; Topka, K.P.; Tarbell, T.D.; Shine, R.A.

    1988-04-01T23:59:59.000Z

    Using the technique of local correlation tracking on a 28 minute time sequence of white-light images of solar granulation, the horizontal flow field on the solar surface is measured. The time series was obtained by the Solar Optical Universal Polarimeter (SOUP) on Spacelab 2 (Space Shuttle flight 51-F) and is free from atmospheric blurring and distortion. The SOUP flow fields have been compared with carefully aligned magnetograms taken over a nine hour period at the Big Bear Solar Observatory before, during, and after the SOUP images. The flow field and the magnetic field agree in considerable detail: vectors which define the flow of the white-light intensity pattern (granulation) point toward magnetic field regions, magnetic fields surround flow cells, and magnetic features move along the flow arrows. The projected locations of free particles (corks) in the measured flow field congregate at the same locations where the magnetic field is observed. 31 references.

  19. Water Visualization and Flooding in Polymer Electrolyte Membrane Fuel Cells

    E-Print Network [OSTI]

    Petta, Jason

    Water Visualization and Flooding in Polymer Electrolyte Membrane Fuel Cells Brian Holsclaw West- 2H2O e- e- e- e- e- H+ H+ H+ Membrane + Schematic of a PEMFC Operation #12;PFR PEM Fuel Cell Plug for membrane Two-phase flow in channels #12;CSTR PEM Fuel Cell Continuous Stirred-Tank Reactor (CSTR) "Perfect

  20. Direct Methanol Fuel Cell Experimental and Model Validation Study

    E-Print Network [OSTI]

    Wang, Chao-Yang

    Direct Methanol Fuel Cell Experimental and Model Validation Study M. Mench, J. Scott, S. Thynell boundary Fuel cell performance Current density distribution measurements Conclusions #12;3 Method, flow rate, species inlet and fuel cell temperature, and humidity. Transparent polycarbonate windows

  1. Analysis of Real World Fuel Cell Degradation (Presentation)

    SciTech Connect (OSTI)

    Kurtz, J.; Wipke, K.; Sprik, S.; Ramsden, T.

    2009-12-08T23:59:59.000Z

    Presentation about the National Renewable Energy Laboratory's Hydrogen Secure Data Center and its work with fuel cell vehicles, fuel cell early market demonstrations, and fuel cell bus demonstrations. This presentation includes results of composite data products and a summary of the analysis objectives and data flow for the projects.

  2. Polycarbonate filter technique for collection of sorted cells

    SciTech Connect (OSTI)

    Folstad, L.; Look, M.; Pallavicini, M.

    1982-01-01T23:59:59.000Z

    We describe the application of polycarbonate filters to the collection of cells sorted by flow cytometry. Cells are sorted directly onto polycarbonate filters and transferred to microscope slides which are then processed to dissolve the filter and remove pore outlines. The technique results in cell preparations which retain cellular morphology and have highcell recovery of 82 to 100%.

  3. Computational Fuel Cell Research and SOFC Modeling at Penn State

    E-Print Network [OSTI]

    multidisciplinary research on fuel cells and advanced batteries for vehicle propulsion, distributed power generation science, multiphase transport, reactive flow, CFD modeling, experimental diagnostics, in- vehicle testing, DMFC, and SOFC #12;ECEC Facilities (>5,000 sq ft) Fuel Cell/Battery Experimental Labs Fuel Cell

  4. MICROFLUIDIC DEVICE WITH INTEGRATED ANTIBODY ARRAYS FOR CELL SIGNALLING

    E-Print Network [OSTI]

    MICROFLUIDIC DEVICE WITH INTEGRATED ANTIBODY ARRAYS FOR CELL SIGNALLING ANALYSIS J. El-Ali1 , S we present the integration of protein arrays with a microfluidic device for analysis of cell a microfluidic segmented flow device that could achieve rapid stimulus and lysis of cells [1][2]. The device had

  5. [Unsegmented continuous-flow sample processing and electrochemical detection of gaseous species]. Final report, March 1, 1985--February 28, 1991

    SciTech Connect (OSTI)

    Mottola, H.A.

    1991-12-31T23:59:59.000Z

    Goals were a continuous-flow, unsegmented, all-gas carrier and/or a segmented liquid/gas interface system for sample introduction and transport to detection/determination point; a regenerable electrode probe base on redox reactions of Fe(II) and Fe(III) complexes with 1, 10-phenanthroline and related ligands; and amperometric/coulometric current measurements providing analyte signals. Gases to be detected included NO{sub x} and SO{sub 2}. This report is divided into 3 parts: preparation of new ligands of 1,10-phenanthroline family; glassy carbon surfaces coated with polymeric films prepared from monomeric units of tris[5-amino-1,10-phenanthroline]iron(II); and sulfite oxidase/hexacyanoferrate modified C paste electrode.

  6. Investigation of the performance and water transport of a polymer electrolyte membrane (pem) fuel cell

    E-Print Network [OSTI]

    Park, Yong Hun

    2009-05-15T23:59:59.000Z

    Fuel cell performance was obtained as functions of the humidity at the anode and cathode sites, back pressure, flow rate, temperature, and channel depth. The fuel cell used in this work included a membrane and electrode assembly (MEA) which...

  7. Investigation of the performance and water transport of a polymer electrolyte membrane (pem) fuel cell 

    E-Print Network [OSTI]

    Park, Yong Hun

    2009-05-15T23:59:59.000Z

    Fuel cell performance was obtained as functions of the humidity at the anode and cathode sites, back pressure, flow rate, temperature, and channel depth. The fuel cell used in this work included a membrane and electrode ...

  8. Solid oxide fuel cell with monolithic core

    DOE Patents [OSTI]

    McPheeters, C.C.; Mrazek, F.C.

    1988-08-02T23:59:59.000Z

    A solid oxide fuel cell in which fuel and oxidant gases undergo an electrochemical reaction to produce an electrical output includes a monolithic core comprised of a corrugated conductive sheet disposed between upper and lower generally flat sheets. The corrugated sheet includes a plurality of spaced, parallel, elongated slots which form a series of closed, linear, first upper and second lower gas flow channels with the upper and lower sheets within which a fuel gas and an oxidant gas respectively flow. Facing ends of the fuel cell are generally V-shaped and provide for fuel and oxidant gas inlet and outlet flow, respectively, and include inlet and outlet gas flow channels which are continuous with the aforementioned upper fuel gas and lower oxidant gas flow channels. The upper and lower flat sheets and the intermediate corrugated sheet are preferably comprised of ceramic materials and are securely coupled together such as by assembly in the green state and sintering together during firing at high temperatures. A potential difference across the fuel cell, or across a stacked array of similar fuel cells, is generated when an oxidant gas such as air and a fuel such as hydrogen gas is directed through the fuel cell at high temperatures, e.g., between 700 C and 1,100 C. 8 figs.

  9. Solid oxide fuel cell with monolithic core

    DOE Patents [OSTI]

    McPheeters, Charles C. (Plainfield, IL); Mrazek, Franklin C. (Hickory Hills, IL)

    1988-01-01T23:59:59.000Z

    A solid oxide fuel cell in which fuel and oxidant gases undergo an electrochemical reaction to produce an electrical output includes a monolithic core comprised of a corrugated conductive sheet disposed between upper and lower generally flat sheets. The corrugated sheet includes a plurality of spaced, parallel, elongated slots which form a series of closed, linear, first upper and second lower gas flow channels with the upper and lower sheets within which a fuel gas and an oxidant gas respectively flow. Facing ends of the fuel cell are generally V-shaped and provide for fuel and oxidant gas inlet and outlet flow, respectively, and include inlet and outlet gas flow channels which are continuous with the aforementioned upper fuel gas and lower oxidant gas flow channels. The upper and lower flat sheets and the intermediate corrugated sheet are preferably comprised of ceramic materials and are securely coupled together such as by assembly in the green state and sintering together during firing at high temperatures. A potential difference across the fuel cell, or across a stacked array of similar fuel cells, is generated when an oxidant gas such as air and a fuel such as hydrogen gas is directed through the fuel cell at high temperatures, e.g., between 700.degree. C. and 1100.degree. C.

  10. Platinum-CatalyzedOxidations of Organic Compounds by Ferric Sulfate: Use of a Redox Fuel Cell to Mediate Complete Oxidation of

    E-Print Network [OSTI]

    Prentiss, Mara

    under mild conditions(60-80°C, 3 M H2S04in water) by Fe(II1) using a catalytic amount of Pt black strategy for removal of contaminants from waste streams and flue gases (1-3). We have found an inorganic rnl) to remove water and trace aldehyde and distilled before use. Glycolic acid (Aldrich), glyoxyilic

  11. Complex Flow Workshop Report

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page onYouTube YouTube Note: Since the YouTube platformBuildingCoalComplex Flow Workshop Report January 17-18, 2012 University

  12. Non-axisymmetric Flows

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for Renewable Energy:Nanowire Solar541,9337,2AprilBig EddyNobelNon-axisymmetric Flows and

  13. High Average Power Laser Gain Medium With Low Optical Distortion Using A Transverse Flowing Liquid Host

    DOE Patents [OSTI]

    Comaskey, Brian J. (Walnut Creek, CA); Ault, Earl R. (Livermore, CA); Kuklo, Thomas C. (Oakdale, CA)

    2005-07-05T23:59:59.000Z

    A high average power, low optical distortion laser gain media is based on a flowing liquid media. A diode laser pumping device with tailored irradiance excites the laser active atom, ion or molecule within the liquid media. A laser active component of the liquid media exhibits energy storage times longer than or comparable to the thermal optical response time of the liquid. A circulation system that provides a closed loop for mixing and circulating the lasing liquid into and out of the optical cavity includes a pump, a diffuser, and a heat exchanger. A liquid flow gain cell includes flow straighteners and flow channel compression.

  14. Advanced Flow Battery Electrodes: Low-cost, High-Performance 50-Year Electrode

    SciTech Connect (OSTI)

    None

    2010-09-01T23:59:59.000Z

    GRIDS Project: Primus Power is developing zinc-based, rechargeable liquid flow batteries that could produce substantially more energy at lower cost than conventional batteries. A flow battery is similar to a conventional battery, except instead of storing its energy inside the cell it stores that energy for future use in chemicals that are kept in tanks that sit outside the cell. One of the most costly components in a flow battery is the electrode, where the electrochemical reactions actually occur. Primus Power is investigating and developing mixed-metal materials for their electrodes that could ultimately reduce the lifetime cost of flow batteries because they are more durable and long-lasting than electrodes found in traditional batteries. Using these electrodes, Primus Power’s flow batteries can be grouped together into robust, containerized storage pods for use by utilities, renewable energy developers, businesses, and campuses.

  15. DISCONTINUOUS GALERKIN BGK METHOD FOR VISCOUS FLOW EQUATIONS: ONE-DIMENSIONAL SYSTEMS

    E-Print Network [OSTI]

    Xu, Kun

    the Riemann solution in the flux construction at a cell interface, the physics of wave propagation that a discontinuous flow distribution is introduced at a cell interface. The artificial kinematic numerical dissi Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (makxu@ust.hk). 1941 #12

  16. Fluid flow monitoring device

    DOE Patents [OSTI]

    McKay, M.D.; Sweeney, C.E.; Spangler, B.S. Jr.

    1993-11-30T23:59:59.000Z

    A flow meter and temperature measuring device are described comprising a tube with a body centered therein for restricting flow and a sleeve at the upper end of the tube to carry several channels formed longitudinally in the sleeve to the appropriate axial location where they penetrate the tube to allow pressure measurements and temperature measurements with thermocouples. The high pressure measurement is made using a channel penetrating the tube away from the body and the low pressure measurement is made at a location at the widest part of the body. An end plug seals the end of the device and holes at its upper end allow fluid to pass from the interior of the tube into a plenum. The channels are made by cutting grooves in the sleeve, the grooves widened at the surface of the sleeve and then a strip of sleeve material is welded to the grooves closing the channels. Preferably the sleeve is packed with powdered graphite before cutting the grooves and welding the strips. 7 figures.

  17. Fluid flow monitoring device

    DOE Patents [OSTI]

    McKay, Mark D. (1426 Socastee Dr., North Augusta, SC 29841); Sweeney, Chad E. (3600 Westhampton Dr., Martinez, GA 30907-3036); Spangler, Jr., B. Samuel (2715 Margate Dr., Augusta, GA 30909)

    1993-01-01T23:59:59.000Z

    A flow meter and temperature measuring device comprising a tube with a body centered therein for restricting flow and a sleeve at the upper end of the tube to carry several channels formed longitudinally in the sleeve to the appropriate axial location where they penetrate the tube to allow pressure measurements and temperature measurements with thermocouples. The high pressure measurement is made using a channel penetrating the tube away from the body and the low pressure measurement is made at a location at the widest part of the body. An end plug seals the end of the device and holes at its upper end allow fluid to pass from the interior of the tube into a plenum. The channels are made by cutting grooves in the sleeve, the grooves widened at the surface of the sleeve and then a strip of sleeve material is welded to the grooves closing the channels. Preferably the sleeve is packed with powdered graphite before cutting the grooves and welding the strips.

  18. Radial flow heat exchanger

    DOE Patents [OSTI]

    Valenzuela, Javier (Hanover, NH)

    2001-01-01T23:59:59.000Z

    A radial flow heat exchanger (20) having a plurality of first passages (24) for transporting a first fluid (25) and a plurality of second passages (26) for transporting a second fluid (27). The first and second passages are arranged in stacked, alternating relationship, are separated from one another by relatively thin plates (30) and (32), and surround a central axis (22). The thickness of the first and second passages are selected so that the first and second fluids, respectively, are transported with laminar flow through the passages. To enhance thermal energy transfer between first and second passages, the latter are arranged so each first passage is in thermal communication with an associated second passage along substantially its entire length, and vice versa with respect to the second passages. The heat exchangers may be stacked to achieve a modular heat exchange assembly (300). Certain heat exchangers in the assembly may be designed slightly differently than other heat exchangers to address changes in fluid properties during transport through the heat exchanger, so as to enhance overall thermal effectiveness of the assembly.

  19. Pyrite oxidation in saturated and Unsaturated Porous Media Flow: AComparison of alternative mathematical modeling approaches

    SciTech Connect (OSTI)

    Xu, Tianfu; White, Stephen P.; Pruess, Karsten

    1998-02-15T23:59:59.000Z

    Pyrite (FeS{sub 2}) is one of the most common naturally occurring minerals that is present in many subsurface environments. It plays an important role in the genesis of enriched ore deposits through weathering reactions, is the most abundant sulfide mineral in many mine tailings, and is the primary source of acid drainage from mines and waste rock piles. The pyrite oxidation reaction serves as a prototype for oxidative weathering processes with broad significance for geoscientific, engineering, and environmental applications. Mathematical modeling of these processes is extremely challenging because aqueous concentrations of key species vary over an enormous range, oxygen inventory and supply are typically small in comparison to pyrite inventory, and chemical reactions are complex, involving kinetic control and microbial catalysis. We present the mathematical formulation of a general multi-phase advective-diffusive reactive transport model for redox processes. Two alternative implementations were made in the TOUGHREACT and TOUGH2-CHEM simulation codes which use sequential iteration and simultaneous solution, respectively. The simulators are applied to reactive consumption of pyrite in (1) saturated flow of oxidizing water, and (2) saturated-unsaturated flow in which oxygen transport occurs in both aqueous and gas phases. Geochemical evolutions predicted from different process models are compared, and issues of numerical accuracy and efficiency are discussed.

  20. Parallel Multiphysics Simulations of Charged Particles in Microfluidic Flows

    E-Print Network [OSTI]

    Bartuschat, Dominik

    2014-01-01T23:59:59.000Z

    The article describes parallel multiphysics simulations of charged particles in microfluidic flows with the waLBerla framework. To this end, three physical effects are coupled: rigid body dynamics, fluid flow modelled by a lattice Boltzmann algorithm, and electric potentials represented by a finite volume discretisation. For solving the finite volume discretisation for the electrostatic forces, a cell-centered multigrid algorithm is developed that conforms to the lattice Boltzmann meshes and the parallel communication structure of waLBerla. The new functionality is validated with suitable benchmark scenarios. Additionally, the parallel scaling and the numerical efficiency of the algorithms are analysed on an advanced supercomputer.

  1. Active combustion flow modulation valve

    DOE Patents [OSTI]

    Hensel, John Peter; Black, Nathaniel; Thorton, Jimmy Dean; Vipperman, Jeffrey Stuart; Lambeth, David N; Clark, William W

    2013-09-24T23:59:59.000Z

    A flow modulation valve has a slidably translating hollow armature with at least one energizable coil wound around and fixably attached to the hollow armature. The energizable coil or coils are influenced by at least one permanent magnet surrounding the hollow armature and supported by an outer casing. Lorentz forces on the energizable coils which are translated to the hollow armature, increase or decrease the flow area to provide flow throttling action. The extent of hollow armature translation depends on the value of current supplied and the direction of translation depends on the direction of current flow. The compact nature of the flow modulation valve combined with the high forces afforded by the actuator design provide a flow modulation valve which is highly responsive to high-rate input control signals.

  2. Review of Methods to Probe Single Cell Metabolism and Bioenergetics

    SciTech Connect (OSTI)

    Vasdekis, Andreas E.; Stephanopoulos, Gregory

    2015-01-01T23:59:59.000Z

    The sampling and manipulation of cells down to the individual has been of substantial interest since the very beginning of Life Sciences. Herein, our objective is to highlight the most recent developments in single cell manipulation, as well as pioneering ones. First, flow-through methods will be discussed, namely methods in which the single cells flow continuously in an ordered manner during their analysis. This section will be followed by confinement techniques that enable cell isolation and confinement in one, two- or three-dimensions. Flow cytometry and droplet microfluidics are the two most common methods of flow-through analysis. While both are high-throughput techniques, their difference lays in the fact that the droplet encapsulated cells experience a restricted and personal microenvironment, while in flow cytometry cells experience similar nutrient and stimuli initial concentrations. These methods are rather well established; however, they recently enabled immense strides in single cell phenotypic analysis, namely the identification and analysis of metabolically distinct individuals from an isogenic population using both droplet microfluidics and flow cytometry.

  3. Pertechnetate (TcO4-) reduction by reactive ferrous iron forms in naturally anoxic, redox transition zone sediments from the Hanford Site, USA

    SciTech Connect (OSTI)

    Peretyazhko, Tetyana; Zachara, John M.; Kukkadapu, Ravi K.; Heald, Steve M.; Kutnyakov, Igor V.; Resch, Charles T.; Arey, Bruce W.; Wang, Chong M.; Kovarik, Libor; Phillips, Jerry L.; Moore, Dean A.

    2012-09-01T23:59:59.000Z

    Technetium is an important environmental contaminant introduced by the processing and disposal of irradiated nuclear fuel and atmospheric nuclear tests. Under oxic conditions technetium is soluble and exists as pertechnatate anion (TcO4-), while under anoxic conditions Tc is usually insoluble and exists as precipitated Tc(IV). Here we investigated abiotic Tc(VII) reduction in mineralogically heterogeneous, Fe(II)-containing sediments. The sediments were collected from a 55 m borehole that sampled a semi-confined aquifer at the Hanford Site, USA that contained a dramatic redox transition zone. One oxic facies (18.0-18.3 m) and five anoxic facies (18.3-18.6 m, 30.8-31.1 m, 39.0-39.3 m, 47.2-47.5 m and 51.5-51.8 m) were selected for this study. Chemical extractions, X-ray diffraction, electron microscopy, and Mössbauer spectroscopy were applied to characterize the Fe(II) mineral suite that included: Fe(II)-phyllosilicates, pyrite, magnetite and siderite. The Fe(II) mineral phase distribution differed between the sediments. Sediment suspensions were adjusted to the same 0.5 M HCl extracted Fe(II) concentration (0.6 mM) for Tc(VII) reduction experiments. Aqueous Fe was low in all sediment suspensions (<2 ?M) and below the Fe(II)aq detection limit (10 ?M). Technetium(VII) reduction occurred in all anoxic sediments at depths greater than 18.3 m and reaction time differed significantly between the sediments (8-219 d). Mössbauer analysis of the Tc-reacted, 30.8-31.1 m sediment confirmed that Tc(VII) was reduced by solid-phase Fe(II), with siderite and Fe(II)-containing phyllosilicates implicated as redox reactive phases. Technetium-XAS analysis demonstrated that Tc associated with sediments was in the Tc(IV) valence state and immobilized as clusters of a TcO2·nH2O-like phase. The speciation of redox product Tc(IV) was not affected by reduction rate or Fe(II) mineralogy.

  4. Subsurface Flow and Transport | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    subsurface related to contaminant transport, carbon cycling, enhanced oil recovery and carbon dioxide sequestration. See a complete list of Subsurface Flow and Transport...

  5. Sample handling for kinetics and molecular assembly in flow cytometry

    SciTech Connect (OSTI)

    Sklar, L.A. [Los Alamos National Lab., NM (United States). National Flow Cytometry Resource]|[Univ. of New Mexico, Albuquerque, NM (United States). School of Medicine; Seamer, L.C.; Kuckuck, F.; Prossnitz, E.; Edwards, B. [Univ. of New Mexico, Albuquerque, NM (United States). School of Medicine; Posner, G. [Northern Arizona Univ., Flagstaff, AZ (United States). Dept. of Chemistry

    1998-07-01T23:59:59.000Z

    Flow cytometry discriminates particle associated fluorescence from the fluorescence of the surrounding medium. It permits assemblies of macromolecular complexes on beads or cells to be detected in real-time with precision and specificity. The authors have investigated two types of robust sample handling systems which provide sub-second resolution and high throughput: (1) mixers which use stepper-motor driven syringes to initiate chemical reactions in msec time frames; and (2) flow injection controllers with valves and automated syringes used in chemical process control. In the former system, the authors used fast valves to overcome the disparity between mixing 100 {micro}ls of sample in 100 msecs and delivering sample to a flow cytometer at 1 {micro}l/sec. Particles were detected within 100 msec after mixing, but turbulence was created which lasted for 1 sec after injection of the sample into the flow cytometer. They used optical criteria to discriminate particles which were out of alignment due to the turbulent flow. Complex sample handling protocols involving multiple mixing steps and sample dilution have also been achieved. With the latter system they were able to automate sample handling and delivery with intervals of a few seconds. The authors used a fluidic approach to defeat turbulence caused by sample introduction. By controlling both sheath and sample with individual syringes, the period of turbulence was reduced to {approximately} 200 msecs. Automated sample handling and sub-second resolution should permit broad analytical and diagnostic applications of flow cytometry.

  6. Redox-driven regulation of microbial community morphogenesis Chinweike Okegbe, Alexa Price-Whelan and Lars EP Dietrich

    E-Print Network [OSTI]

    Dietrich, Lars

    that oxygen gradient formation not only affects the metabolism and survival of cells in bacterial communities- anisms, researchers in many fields have traditionally focused on the high metabolic activity or exposure availability of electron donors and acceptors -- has critical implica- tions for metabolism

  7. Proceedings of FUELCELL2005 Third International Conference on Fuel Cell Science, Engineering and Technology

    E-Print Network [OSTI]

    Stefanopoulou, Anna

    management is necessary. The heat associated with the range of power needed for a typical passenger vehicle voltage is calculated quasi-statically. Measurement data of a 1.25kW, 24-cell fuel cell stack Molecular mass [kg/mol] m Mass [kg] m Mass flow rate [kg/s] nCells Number of fuel cells [-] P Power [W] p

  8. Method for single-cell mass and electrophoretic mobility measurement

    E-Print Network [OSTI]

    Dextras, Philip

    2010-01-01T23:59:59.000Z

    Analysis of single cells using flow cytometry techniques has created a wealth of knowledge about cellular phenomena that could not be obtained by population average measurements. As these techniques are integrated with ...

  9. Bioinspired Multivalent DNA Network for Capture and Release of Cells

    E-Print Network [OSTI]

    Zhao, Weian

    Capture and isolation of flowing cells and particulates from body fluids has enormous implications in diagnosis, monitoring, and drug testing, yet monovalent adhesion molecules used for this purpose result in inefficient ...

  10. alkaline membrane cell: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    fuelAnalysis of PtC electrode performance in a flowing- electrolyte alkaline fuel cell Fikile R 17 October 2011 Accepted 18 October 2011 Available online 12 November 2011...

  11. Rényi entropy flows from quantum heat engines

    E-Print Network [OSTI]

    Mohammad H. Ansari; Yuli V. Nazarov

    2015-03-20T23:59:59.000Z

    We evaluate Renyi entropy flows from generic quantum heat engines (QHE) to a weakly-coupled probe environment kept in thermal equilibrium. We show that the flows are determined not only by heat flow but also by a quantum coherent flow that can be separately measured in experiment apart from the heat flow measurement. The same pertains to Shanon entropy flow. This appeals for a revision of the concept of entropy flows in quantum nonequlibrium thermodynamics.

  12. Gas block mechanism for water removal in fuel cells

    DOE Patents [OSTI]

    Issacci, Farrokh; Rehg, Timothy J.

    2004-02-03T23:59:59.000Z

    The present invention is directed to apparatus and method for cathode-side disposal of water in an electrochemical fuel cell. There is a cathode plate. Within a surface of the plate is a flow field comprised of interdigitated channels. During operation of the fuel cell, cathode gas flows by convection through a gas diffusion layer above the flow field. Positioned at points adjacent to the flow field are one or more porous gas block mediums that have pores sized such that water is sipped off to the outside of the flow field by capillary flow and cathode gas is blocked from flowing through the medium. On the other surface of the plate is a channel in fluid communication with each porous gas block mediums. The method for water disposal in a fuel cell comprises installing the cathode plate assemblies at the cathode sides of the stack of fuel cells and manifolding the single water channel of each of the cathode plate assemblies to the coolant flow that feeds coolant plates in the stack.

  13. Osmotic water permeability of human red cells

    SciTech Connect (OSTI)

    Terwilliger, T.C.; Solomon, A.K.

    1981-05-01T23:59:59.000Z

    The osmotic water permeability of human red cells has been reexamined with a stopped-flow device and a new perturbation technique. Small osmotic gradients are used to minimize the systematic error caused by nonlinearities in the relationship between cell volume and light scattering. Corrections are then made for residual systematic error. Our results show that the hydraulic conductivity, Lp, is essentially independent of the direction of water flow and of osmolality in the range 184-365 mosM. the mean value of Lp obtained obtained was 1.8 +/- 0.1 (SEM) X 10-11 cm3 dyne -1 s-1.

  14. Modular fuel-cell stack assembly

    DOE Patents [OSTI]

    Patel, Pinakin (Danbury, CT); Urko, Willam (West Granby, CT)

    2008-01-29T23:59:59.000Z

    A modular multi-stack fuel-cell assembly in which the fuel-cell stacks are situated within a containment structure and in which a gas distributor is provided in the structure and distributes received fuel and oxidant gases to the stacks and receives exhausted fuel and oxidant gas from the stacks so as to realize a desired gas flow distribution and gas pressure differential through the stacks. The gas distributor is centrally and symmetrically arranged relative to the stacks so that it itself promotes realization of the desired gas flow distribution and pressure differential.

  15. Network Flow Optimization under Uncertainty

    E-Print Network [OSTI]

    Tesfatsion, Leigh

    Network model in words Minimize the cost of satisfying demands for electric energy By: imports, exports and electricity Subject to: conservation of energy flows (net after losses), lower and upper bounds on flows is a reactive approach: how would the optimal solution have changed if I'd only known? · Proactive approaches

  16. Wavy flow cooling concept for turbine airfoils

    DOE Patents [OSTI]

    Liang, George (Palm City, FL)

    2010-08-31T23:59:59.000Z

    An airfoil including an outer wall and a cooling cavity formed therein. The cooling cavity includes a leading edge flow channel located adjacent a leading edge of the airfoil and a trailing edge flow channel located adjacent a trailing edge of the airfoil. Each of the leading edge and trailing edge flow channels define respective first and second flow axes located between pressure and suction sides of the airfoil. A plurality of rib members are located within each of the flow channels, spaced along the flow axes, and alternately extending from opposing sides of the flow channels to define undulating flow paths through the flow channels.

  17. Vertical flow chemical detection portal

    DOE Patents [OSTI]

    Linker, K.L.; Hannum, D.W.; Conrad, F.J.

    1999-06-22T23:59:59.000Z

    A portal apparatus is described for screening objects or persons for the presence of trace amounts of chemical substances such as illicit drugs or explosives. The apparatus has a test space, in which a person may stand, defined by two generally upright sides spanned by a horizontal transom. One or more fans in the transom generate a downward air flow (uni-directional) within the test space. The air flows downwardly from a high pressure upper zone, past the object or person to be screened. Air moving past the object dislodges from the surface thereof both volatile and nonvolatile particles of the target substance. The particles are entrained into the air flow which continues flowing downward to a lower zone of reduced pressure, where the particle-bearing air stream is directed out of the test space and toward preconcentrator and detection components. The sides of the portal are specially configured to partially contain and maintain the air flow. 3 figs.

  18. Two-dimensional AMR simulations of colliding flows

    E-Print Network [OSTI]

    Niklaus, Markus; Niemeyer, Jens C

    2009-01-01T23:59:59.000Z

    Colliding flows are a commonly used scenario for the formation of molecular clouds in numerical simulations. Due to the thermal instability of the warm neutral medium, turbulence is produced by cooling. We carry out a two-dimensional numerical study of such colliding flows in order to test whether statistical properties inferred from adaptive mesh refinement (AMR) simulations are robust with respect to the applied refinement criteria. We compare probability density functions of various quantities as well as the clump statistics and fractal dimension of the density fields in AMR simulations to a static-grid simulation. The static grid with 2048^2 cells matches the resolution of the most refined subgrids in the AMR simulations. The density statistics is reproduced fairly well by AMR. Refinement criteria based on the cooling time or the turbulence intensity appear to be superior to the standard technique of refinement by overdensity. Nevertheless, substantial differences in the flow structure become apparent. In...

  19. Polymer selection and cell design for electric-vehicle supercapacitors

    SciTech Connect (OSTI)

    Mastragostino, M.; Arbizzani, C.; Paraventi, R.; Zanelli, A.

    2000-02-01T23:59:59.000Z

    Supercapacitors are devices for applications requiring high operating power levels, such as secondary power sources in electric vehicles (EVs) to provide peak power for acceleration and hill climbing. While electronically conducting polymers yield different redox supercapacitor configurations, devices with the n-doped polymer as the negative electrode and the p-doped polymer as the positive one are the most promising for EV applications. Indeed, this type of supercapacitor has a high operating potential, is able to deliver all the doping charge and, when charged, has both electrodes in the conducting (p- and n-doped) states. This study reports selection criteria for polymer materials and cell design for high performance EV supercapacitors and experimental results of selected polymer materials.

  20. Recurrent flow analysis in spatiotemporally chaotic 2-dimensional Kolmogorov flow

    E-Print Network [OSTI]

    Dan Lucas; Rich Kerswell

    2015-04-01T23:59:59.000Z

    Motivated by recent success in the dynamical systems approach to transitional flow, we study the efficiency and effectiveness of extracting simple invariant sets (recurrent flows) directly from chaotic/turbulent flows and the potential of these sets for providing predictions of certain statistics of the flow. Two-dimensional Kolmogorov flow (the 2D Navier-Stokes equations with a sinusoidal body force) is studied both over a square [0, 2{\\pi}]2 torus and a rectangular torus extended in the forcing direction. In the former case, an order of magnitude more recurrent flows are found than previously (Chandler & Kerswell 2013) and shown to give improved predictions for the dissipation and energy pdfs of the chaos via periodic orbit theory. Over the extended torus at low forcing amplitudes, some extracted states mimick the statistics of the spatially-localised chaos present surprisingly well recalling the striking finding of Kawahara & Kida (2001) in low-Reynolds-number plane Couette flow. At higher forcing amplitudes, however, success is limited highlighting the increased dimensionality of the chaos and the need for larger data sets. Algorithmic developments to improve the extraction procedure are discussed.

  1. Flow Rate Measurements Using Flow-Induced Pipe Vibration

    SciTech Connect (OSTI)

    R. P. Evans; Jonathan D. Blotter; Alan G. Stephens

    2004-03-01T23:59:59.000Z

    This paper focuses on the possibility of a non-intrusive, low cost, flow rate measurement technique. The technique is based on signal noise from an accelerometer attached to the surface of the pipe. The signal noise is defined as the standard deviation of the frequency averaged time series signal. Experimental results are presented that indicate a nearly quadratic relationship between the signal noise and mass flow rate in the pipe. It is also shown that the signal noise - flow rate relationship is dependant on the pipe material and diameter.

  2. Single chamber fuel cells: Flow geometry, rate and composition considerations

    E-Print Network [OSTI]

    Stefan, Ionel C.; Jacobson, Craig P.; Visco, Steven J.; De Jonghe, Lutgard C.

    2003-01-01T23:59:59.000Z

    In the case of a propane- air mixture, used in our studies,in Figure 1, in propane-air mixtures of different ratios andcase does the 10% propane-air mixture lead to the highest

  3. An algebraic model for a zinc/bromine flow cell

    E-Print Network [OSTI]

    Simpson, Gary Don

    1988-01-01T23:59:59.000Z

    response of current density of coulombic efficiency of Brz in anodic feed of Zri+z in cathodic feed of electrolyte potential at anode . of electrolyte potential at cathode of current density for unequal tanks of coulombic efflciency for unequal... of the electrodes and the separator. An electrolytic solution containing Zn+s and Br (among other things) is forced through the gaps between the electrodes and the separator. After the solution exits the reactor, it enters the associated storage tank...

  4. Flow cytometry aids basic cell biology research and drug discovery

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    including very deep wells already producing oil and gas and drilling operations for new wells. Wireless technology collects real-time information from oil and gas wells April,...

  5. Flow Cells for Energy Storage Workshop Overview | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't YourTransport inEnergy0.pdf Flash2010-60.pdf2 DOE Hydrogen and FuelFlorida companyOverview

  6. Flow Cells for Energy Storage Workshop Summary Report | Department of

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't YourTransport inEnergy0.pdf Flash2010-60.pdf2 DOE Hydrogen and FuelFlorida

  7. Electrically Integrated Graphene on Silicon Nitride Liquid Flow Cells for

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power AdministrationField Campaign:INEAWater Use Goal 4:Administration826VehiclesHigh

  8. Renaissance in Flow-Cell Technologies: Recent Advancements and Future

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn'tOrigin of ContaminationHubs+18,new2004_v1.3_5.0.zipFlorida4Visitors3 * August 2004

  9. US energy flow - 1984

    SciTech Connect (OSTI)

    Briggs, C.K.; Borg, I.Y.

    1985-07-01T23:59:59.000Z

    The 1984 energy flow diagram for the USA has been constructed using Department of Energy data. It is a convenient graphical device to show supply and demand as well as the size of end-use sectors. A 4% increase in overall energy consumption represented a reversal in a downward trend started in 1979. All indicators pointed to more healthy industrial and farm economies in 1984 than in the previous two years, which accounted for some part of the increase in energy use. While domestic crude oil production remained stable, oil imports rose eight percent also reversing a long-standing trend. Seventy-two million barrels of oil primarily from Mexico and the United Kingdom were added to the Strategic Petroleum Reserve bringing the total oil stored at year end to 451 million barrels. At the same time 49 million barrels of oil were produced from the government-owned Naval Petroleum Reserve No. 1 (Elk Hills, CA). Energy use in all end-use sectors grew in 1984 which is in keeping with increases in use of all types of fossil fuels as well as electricity. Increase in electrical power demand continued to exceed forecasts, and during 1984 contracts for imports to the northeast US were negotiated with Canada. Nuclear power contributed 15% of total power generated in the US. At year end there were 86 licensed reactors and 44 in either start-up or construction stages. Six were canceled or abandoned during construction during the year. 11 refs., 4 figs., 3 tabs.

  10. Addition of non-reacting gases to the anode flow field of DMFCs leading to improved performance

    E-Print Network [OSTI]

    Zhao, Tianshou

    injection; Flow velocity; Void fraction; Flow field 1. Introduction Direct methanol fuel cells (DMFC), using power sources for portable electronic devices, electric vehicles, and other applications, because and better dynamics as well as lower investment and operating costs [1­6]. The commercialization of DMFC is

  11. Ceramic Cross Flow Recuperator Design Parameters

    E-Print Network [OSTI]

    Gonzalez, J. M.; Rebello, W. J.

    1981-01-01T23:59:59.000Z

    the performance of the ceramic recuperator in various industrial furnaces. The ceramic cross flow recuperator core has multiple rectangular flow passages (perpendicular to each other) for the air and gas. Various flow passages are available contingent upon...

  12. Two phase flow in capillary tubes

    E-Print Network [OSTI]

    Suo, Mikio

    1963-01-01T23:59:59.000Z

    The flow of two phases, gas and liquid, has been studied in horizontal tubes of capillary diameter. The flow has been primarily studied in the regime where the gas flows as long bubbles separated from the wall of the tube ...

  13. Flow distribution channels to control flow in process channels

    DOE Patents [OSTI]

    Tonkovich, Anna Lee; Arora, Ravi; Kilanowski, David

    2014-10-28T23:59:59.000Z

    The invention describes features that can be used to control flow to an array of microchannels. The invention also describes methods in which a process stream is distributed to plural microchannels.

  14. The transition from two phase bubble flow to slug flow

    E-Print Network [OSTI]

    Radovcich, Nick A.

    1962-01-01T23:59:59.000Z

    The process of transition from bubble to slug flow in a vertical pipe has been studied analytically and experimentally. An equation is presented which gives the agglomeration time as a function of void fraction, channel ...

  15. Water injected fuel cell system compressor

    DOE Patents [OSTI]

    Siepierski, James S. (Williamsville, NY); Moore, Barbara S. (Victor, NY); Hoch, Martin Monroe (Webster, NY)

    2001-01-01T23:59:59.000Z

    A fuel cell system including a dry compressor for pressurizing air supplied to the cathode side of the fuel cell. An injector sprays a controlled amount of water on to the compressor's rotor(s) to improve the energy efficiency of the compressor. The amount of water sprayed out the rotor(s) is controlled relative to the mass flow rate of air inputted to the compressor.

  16. Thermocapillary Flow on Superhydrophobic Surfaces

    E-Print Network [OSTI]

    Baier, Tobias; Hardt, Steffen

    2010-01-01T23:59:59.000Z

    A liquid in Cassie-Baxter state above a structured superhydrophobic surface is ideally suited for surface driven transport due to its large free surface fraction in close contact to a solid. We investigate thermal Marangoni flow over a superhydrophobic array of fins oriented parallel or perpendicular to an applied temperature gradient. In the Stokes limit we derive an analytical expression for the bulk flow velocity above the surface and compare it with numerical solutions of the Navier-Stokes equation. Even for moderate temperature gradients comparatively large flow velocities are induced, suggesting to utilize this principle for microfluidic pumping.

  17. Universal Quantification for Self-Organized Criticality in Atmospheric Flows

    E-Print Network [OSTI]

    A. Mary Selvam

    1997-10-09T23:59:59.000Z

    Atmospheric flows exhibit selfsimilar fluctuations on all scales(space-time) ranging from climate(kilometers/years) to turbulence(millimeters/seconds) manifested as fractal geometry to the global cloud cover pattern concomitant with inverse power law form for power spectra of temporal fluctuations. Selfsimilar fluctuations implying long-range correlations are ubiquitous to dynamical systems in nature and are identified as signatures of self-organized criticality in atmospheric flows. Also, mathematical models for simulation and prediction of atmospheric flows are nonlinear and computer realizations give unrealistic solutions because of deterministic chaos, a direct consequence of finite precision round-off error doubling for each iteration of iterative computations incorporated in long-term numerical integration schemes used for model solutions An alternative non-deterministic cell dynamical system model predicts, (a): the observed self organized criticality as a consequence of quantumlike mechanics governing flow dynamics,.(b):atmospheric flows trace an overall logarithmic spiral trajectory with the quasiperiodic Penrose tiling pattern for the internal structure,(c): eddy circulation structure follows Kepler's third law of planetary motion and results in inverse square law form for centripetal acceleration. The inertial masses representing the eddy circulation therefore follow laws analogous to the Newton's inverse square law for gravitation. The model is similar to a superstring model for subatomic dynamics which unifies quantum mechanical and classical concept and incorporates gravitational forces along with nuclear and electromagnetic forces.

  18. Exploring multi-layer flow network of international trade based on flow distances

    E-Print Network [OSTI]

    Shen, Bin; Zheng, Qiuhua

    2015-01-01T23:59:59.000Z

    Based on the approach of flow distances, the international trade flow system is studied from the perspective of multi-layer flow network. A model of multi-layer flow network is proposed for modelling and analyzing multiple types of flows in flow systems. Then, flow distances are introduced, and symmetric minimum flow distance is presented. Subsequently, we discuss the establishment of the multi-layer flow networks of international trade from two coupled viewpoints, i.e., the viewpoint of commodity flow and that of money flow. Thus, the multi-layer flow networks of international trade is explored. First, trading "trophic levels" are adopted to depict positions that economies occupied in the flow network. We find that the distributions of trading "trophic levels" have the similar clustering pattern for different types of commodity, and there are some regularities between money flow network and commodity flow network. Second, we find that active and competitive countries trade a wide spectrum of products, while ...

  19. Fuel Cells

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the major national security imperatives of this century. Get Expertise Rod Borup MPA-11, Fuel Cell Program Manager Email Andrew Dattelbaum MPA-11 Group Leader Email Melissa Fox...

  20. Colorado: Isothermal Battery Calorimeter Quantifies Heat Flow...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Isothermal Battery Calorimeter Quantifies Heat Flow, Helps Make Safer, Longer-lasting Batteries Colorado: Isothermal Battery Calorimeter Quantifies Heat Flow, Helps Make Safer,...