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Sample records for secondary electrochemical cell

  1. Electrochemical cell

    DOEpatents

    Kaun, Thomas D. (New Lenox, IL)

    1984-01-01

    An improved secondary electrochemical cell is disclosed having a negative electrode of lithium aluminum, a positive electrode of iron sulfide, a molten electrolyte of lithium chloride and potassium chloride, and the combination that the fully charged theoretical capacity of the negative electrode is in the range of 0.5-1.0 that of the positive electrode. The cell thus is negative electrode limiting during discharge cycling. Preferably, the negative electrode contains therein, in the approximate range of 1-10 volume % of the electrode, an additive from the materials of graphitized carbon, aluminum-iron alloy, and/or magnesium oxide.

  2. Corrosion resistant positive electrode for high-temperature, secondary electrochemical cell

    DOEpatents

    Otto, Neil C. (Chicago, IL); Warner, Barry T. (South Holland, IL); Smaga, John A. (Lemont, IL); Battles, James E. (Oak Forest, IL)

    1983-01-01

    The corrosion rate of low carbon steel within a positive electrode of a high-temperature, secondary electrochemical cell that includes FeS as active material is substantially reduced by incorporating therein finely divided iron powder in stoichiometric excess to the amount required to form FeS in the fully charged electrode. The cell typically includes an alkali metal or alkaline earth metal as negative electrode active material and a molten metal halide salt as electrolyte. The excess iron permits use of inexpensive carbon steel alloys that are substantially free of the costly corrosion resistant elements chromium, nickel and molybdenum while avoiding shorten cell life resulting from high corrosion rates.

  3. Corrosion resistant positive electrode for high-temperature, secondary electrochemical cell

    DOEpatents

    Otto, N.C.; Warner, B.T.; Smaga, J.A.; Battles, J.E.

    1982-07-07

    The corrosion rate of low carbon steel within a positive electrode of a high-temperature, secondary electrochemical cell that includes FeS as active material is substantially reduced by incorporating therein finely divided iron powder in stoichiometric excess to the amount required to form FeS in the fully charged electrode. The cell typically includes an alkali metal or alkaline earth metal as negative electrode active material and a molten metal halide salt as electrolyte. The excess iron permits use of inexpensive carbon steel alloys that are substantially free of the costly corrosion resistant elements chromium, nickel and molybdenum while avoiding shorten cell life resulting from high corrosion rates.

  4. Method of forming components for a high-temperature secondary electrochemical cell

    DOEpatents

    Mrazek, Franklin C. (Hickory Hills, IL); Battles, James E. (Oak Forest, IL)

    1983-01-01

    A method of forming a component for a high-temperature secondary electrochemical cell having a positive electrode including a sulfide selected from the group consisting of iron sulfides, nickel sulfides, copper sulfides and cobalt sulfides, a negative electrode including an alloy of aluminum and an electrically insulating porous separator between said electrodes. The improvement comprises forming a slurry of solid particles dispersed in a liquid electrolyte such as the lithium chloride-potassium chloride eutetic, casting the slurry into a form having the shape of one of the components and smoothing the exposed surface of the slurry, cooling the cast slurry to form the solid component, and removing same. Electrodes and separators can be thus formed.

  5. Method of forming components for a high-temperature secondary electrochemical cell

    DOEpatents

    Mrazek, F.C.; Battles, J.E.

    1981-05-22

    A method of forming a component for a high-temperature secondary electrochemical cell having a positive electrode including a sulfide selected from the group consisting of iron sulfides, nickel sulfides, copper sulfides and cobalt sulfides, a negative electrode including an alloy of aluminum and an electrically insulating porous separator between said electrodes is described. The improvement comprises forming a slurry of solid particles dispersed in a liquid electrolyte such as the lithium chloride-potassium chloride eutectic, casting the slurry into a form having the shape of one of the components and smoothing the exposed surface of the slurry, cooling the cast slurry to form the solid component, and removing same. Electrodes and separators can be thus formed.

  6. Electrochemical cell

    DOEpatents

    Redey, L.I.; Vissers, D.R.; Prakash, J.

    1994-02-01

    An electrochemical cell is described having a bimodal positive electrode, a negative electrode of an alkali metal, and a compatible electrolyte including an alkali metal salt molten at the cell operating temperature. The positive electrode has an electrochemically active layer of at least one transition metal chloride at least partially present as a charging product, and additives of bromide and/or iodide and sulfur in the positive electrode or the electrolyte. Electrode volumetric capacity is in excess of 400 Ah/cm[sup 3]; the cell can be 90% recharged in three hours and can operate at temperatures below 160 C. There is also disclosed a method of reducing the operating temperature and improving the overall volumetric capacity of an electrochemical cell and for producing a positive electrode having a BET area greater than 6[times]10[sup 4] cm[sup 2]/g of Ni. 8 figures.

  7. Electrochemical cell

    DOEpatents

    Redey, Laszlo I. (Downers Grove, IL); Vissers, Donald R. (Naperville, IL); Prakash, Jai (Downers Grove, IL)

    1994-01-01

    An electrochemical cell having a bimodal positive electrode, a negative electrode of an alkali metal, and a compatible electrolyte including an alkali metal salt molten at the cell operating temperature. The positive electrode has an electrochemically active layer of at least one transition metal chloride at least partially present as a charging product, and additives of bromide and/or iodide and sulfur in the positive electrode or the electrolyte. Electrode volumetric capacity is in excess of 400 Ah/cm.sup.3 ; the cell can be 90% recharged in three hours and can operate at temperatures below 160.degree. C. There is also disclosed a method of reducing the operating temperature and improving the overall volumetric capacity of an electrochemical cell and for producing a positive electrode having a BET area greater than 6.times.10.sup.4 cm.sup.2 /g of Ni.

  8. Electrochemical cell

    DOEpatents

    Redey, Laszlo I. (6851 Carpenter St., Downers Grove, IL 60516); Vissers, Donald R. (611 Clover Ct., Naperville, IL 60540); Prakash, Jai (2205 Arbor Cir. 8, Downers Grove, IL 60515)

    1996-01-01

    An electrochemical cell having a bimodal positive electrode, a negative electrode of an alkali metal, and a compatible electrolyte including an alkali metal salt molten at the cell operating temperature. The positive electrode has an electrochemically active layer of at least one transition metal chloride at least partially present as a charging product, and additives of bromide and/or iodide and sulfur in the positive electrode or the electrolyte. Electrode volumetric capacity is in excess of 400 Ah/cm.sup.3 ; the cell can be 90% recharged in three hours and can operate at temperatures below 160.degree. C. There is also disclosed a method of reducing the operating temperature and improving the overall volumetric capacity of an electrochemical cell and for producing a positive electrode having a BET area greater than 6.times.10.sup.4 cm.sup.2 /g of Ni.

  9. Electrochemical cell

    DOEpatents

    Redey, Laszlo I. (Downers Grove, IL); Vissers, Donald R. (Naperville, IL); Prakash, Jai (Downers Grove, IL)

    1994-01-01

    An electrochemical cell having an alkali metal negative electrode such as sodium and a positive electrode including Ni or transition metals, separated by a .beta." alumina electrolyte and NaAlCl.sub.4 or other compatible material. Various concentrations of a bromine, iodine and/or sulfur containing additive and pore formers are disclosed, which enhance cell capacity and power. The pore formers may be the ammonium salts of carbonic acid or a weak organic acid or oxamide or methylcellulose.

  10. Electrochemical cell

    DOEpatents

    Redey, Laszlo I. (Downers Grove, IL); Myles, Kevin M. (Downers Grove, IL); Vissers, Donald R. (Naperville, IL); Prakash, Jai (Downers Grove, IL)

    1996-01-01

    An electrochemical cell with a positive electrode having an electrochemically active layer of at least one transition metal chloride. A negative electrode of an alkali metal and a compatible electrolyte including an alkali metal salt molten at cell operating temperature is included in the cell. The electrolyte is present at least partially as a corrugated .beta." alumina tube surrounding the negative electrode interior to the positive electrode. The ratio of the volume of liquid electrolyte to the volume of the positive electrode is in the range of from about 0.1 to about 3. A plurality of stacked electrochemical cells is disclosed each having a positive electrode, a negative electrode of an alkali metal molten at cell operating temperature, and a compatible electrolyte. The electrolyte is at least partially present as a corrugated .beta." alumina sheet separating the negative electrode and interior to the positive electrodes. The alkali metal is retained in a porous electrically conductive ceramic, and seals for sealing the junctures of the electrolyte and the adjacent electrodes at the peripheries thereof.

  11. Electrochemical cell

    DOEpatents

    Redey, L.I.; Myles, K.M.; Vissers, D.R.; Prakash, J.

    1996-07-02

    An electrochemical cell is described with a positive electrode having an electrochemically active layer of at least one transition metal chloride. A negative electrode of an alkali metal and a compatible electrolyte including an alkali metal salt molten at cell operating temperature is included in the cell. The electrolyte is present at least partially as a corrugated {beta}{double_prime} alumina tube surrounding the negative electrode interior to the positive electrode. The ratio of the volume of liquid electrolyte to the volume of the positive electrode is in the range of from about 0.1 to about 3. A plurality of stacked electrochemical cells is disclosed each having a positive electrode, a negative electrode of an alkali metal molten at cell operating temperature, and a compatible electrolyte. The electrolyte is at least partially present as a corrugated {beta}{double_prime} alumina sheet separating the negative electrode and interior to the positive electrodes. The alkali metal is retained in a porous electrically conductive ceramic, and seals for sealing the junctures of the electrolyte and the adjacent electrodes at the peripheries thereof. 8 figs.

  12. Electrochemical cell

    DOEpatents

    Nagy, Z.; Yonco, R.M.; You, H.; Melendres, C.A.

    1992-08-25

    An electrochemical cell has a layer-type or sandwich configuration with a Teflon center section that houses working, reference and counter electrodes and defines a relatively narrow electrolyte cavity. The center section is surrounded on both sides with thin Teflon membranes. The membranes are pressed in place by a pair of Teflon inner frames which are in turn supported by a pair of outer metal frames. The pair of inner and outer frames are provided with corresponding, appropriately shaped slits that are in plane generally transverse to the plane of the working electrode and permit X-ray beams to enter and exit the cell through the Teflon membranes that cover the slits so that the interface between the working electrode and the electrolyte within the cell may be analyzed by transmission geometry. In one embodiment, the center section consists of two parts, one on top of the other. Alternatively, the center section of the electrochemical cell may consist of two intersliding pieces or may be made of a single piece of Teflon sheet material. The electrolyte cavity is shaped so that the electrochemical cell can be rotated 90[degree] in either direction while maintaining the working and counter electrodes submerged in the electrolyte. 5 figs.

  13. Electrochemical cell

    DOEpatents

    Nagy, Zoltan (Woodridge, IL); Yonco, Robert M. (LaGrange, IL); You, Hoydoo (Naperville, IL); Melendres, Carlos A. (Lemont, IL)

    1992-01-01

    An electrochemical cell has a layer-type or sandwich configuration with a Teflon center section that houses working, reference and counter electrodes and defines a relatively narrow electrolyte cavity. The center section is surrounded on both sides with thin Teflon membranes. The membranes are pressed in place by a pair of Teflon inner frames which are in turn supported by a pair of outer metal frames. The pair of inner and outer frames are provided with corresponding, appropriately shaped slits that are in plane generally transverse to the plane of the working electrode and permit X-ray beams to enter and exit the cell through the Teflon membranes that cover the slits so that the interface between the working electrode and the electrolyte within the cell may be analyzed by transmission geometry. In one embodiment, the center section consists of two parts, one on top of the other. Alternatively, the center section of the electrochemical cell may consist of two intersliding pieces or may be made of a single piece of Teflon sheet material. The electrolyte cavity is shaped so that the electrochemical cell can be rotated 90.degree. in either direction while maintaining the working and counter electrodes submerged in the electrolyte.

  14. Electrochemical cell

    DOEpatents

    Redey, L.I.; Vissers, D.R.; Prakash, J.

    1994-08-23

    An electrochemical cell is described having an alkali metal negative electrode such as sodium and a positive electrode including Ni or transition metals, separated by a [beta] alumina electrolyte and NaAlCl[sub 4] or other compatible material. Various concentrations of a bromine, iodine and/or sulfur containing additive and pore formers are disclosed, which enhance cell capacity and power. The pore formers may be the ammonium salts of carbonic acid or a weak organic acid or oxamide or methylcellulose. 6 figs.

  15. The electrochemical behaviors of Zn-Al-La-hydrotalcite in Zn-Ni secondary cells

    NASA Astrophysics Data System (ADS)

    Fan, Xinming; Yang, Zhanhong; Xie, Xiaoe; Long, Wei; Wang, Ruijuan; Hou, Zhilin

    2013-11-01

    Zn-Al-La-CO3 layered double hydroxides (LDHs) are prepared by the constant pH co-precipitation method and proposed as a novel anodic material in Zinc-Nickel secondary cells. The X-ray diffraction (XRD) patterns and scanning electron microscopy (SEM) images reveal that the as-prepared samples are well-crystallized and hexagon layer structure. Electrochemical performances of Zn-Al-La-hydrotalcites with different Zn/Al/La molar ratios are investigated by galvanostatic charge-discharge measurements, cyclic voltammograms (CV) and Tafel polarization curves. In comparison with the Zn-Al-hydrotalcite, Zn-Al-La-hydrotalcites with different Zn/Al/La molar ratios have more stable cycling performance. After 400 cell cycles, Zn-Al-La-LDH with Zn/Al/La = 3:0.8:0.2 retains specific discharge capacity of 297 mAh g-1 with a retention rate of 79.0%, which is much superior to that of 205 mAh g-1 with a retention rate of 53.5% for the Zn-Al-La-LDH with Zn/Al/La = 3:0.9:0.1 and 241 mAh g-1 with a retention rate of 69.0% for the Zn-Al-La-LDH with Zn/Al/La = 3:0.6:0.4. The results demonstrate that the Zn-Al-La-LDH with Zn/Al/La = 3:0.8:0.2 has the best reversible cycling behavior. The CV exhibits well reversibility and the Tafel polarization curves reveal more positive corrosion potential for Zn-Al-La-hydrotalcite.

  16. Electrochemical cell

    SciTech Connect

    Heuts, J.J.F.G.; Willems, J.J.G.S.A.

    1987-10-13

    An electrochemical cell is described comprising a negative electrode. The electrochemically active material of which consists of an intermetallic compound forming a hydride with hydrogen, which compound has the CaCu/sub 5/-structure and the compositional formula AB/sub m/C/sub n/, where m+n is between 4.8 and 5.4, where n is between 0.05 and 0.6, in which A consists of Misch-metal or of one or more elements selected from the group consisting of Y, Ti, Hf, Zr, Ca, Th, La and the remaining rare earth metals, in which the total atomic quantities of the elements Y, Ti, Hf and Zr may not be more than 40% of A. B consists of two or more elements selected from the group formed by Ni, Co, Cu, Fe and Mn, where the maximum atomic quantity per gram atom of A is for Ni: 3.5, for Co:3.5, for Cu:3.5, for Fe:2.0 and for Mn:1.0, and C consists of one or more elements selected from the group formed by Al, Cr and Si in the indicated atomic quantities: Al:0.05-0.6, Cr:0.05-0.5 and Si:0.05-0.5, characterized in that the electrochemically active material additionally comprises one or more metals selected from the group formed by Pd, Pt, Ir and Rh, the atomic quantity per gram atom of A being from 0.001 to 0.5.

  17. The electrochemical performances of Zn-Sn-Al-hydrotalcites in Zn-Ni secondary cells

    NASA Astrophysics Data System (ADS)

    Wang, Tingting; Yang, Zhanhong; Yang, Bin; Wang, Ruijuan; Huang, Jianhang

    2014-07-01

    Zn-Sn-Al-hydrotalcites (LDHs) have been successfully prepared by hydrothermal method and applied as a novel anodic active material in Zn-Ni secondary batteries. The scanning electron microscopy (SEM), X-ray diffractometer (XRD) and FT-IR tests are performed to investigate the morphology and microstructure of Zn-Sn-Al-hydrotalcites. Electrochemical performances of Zn-Sn-Al-hydrotalcites with different Zn/Sn/Al molar ratios are investigated through galvanostatic charge-discharge measurements, cyclic voltammograms (CV) and Tafel polarization curves. Compared with Zn-Al-LDH without Sn addition, Zn-Sn-Al-LDHs still present hexagon layer structure, and present more excellent electrochemical performance. And Zn-Sn-Al-LDH with the molar ratio of 2.8:0.2:1 shows a better cycle stability than the other samples. The results demonstrate that Sn addition can help to perfect the electrochemical performance of zinc electrode with Zn-Sn-Al-LDHs. At the same time, CV tests indicate well reversibility and Tafel curves reveal more positive corrosion potential for Zn-Sn-Al-LDHs.

  18. Electrochemical cell method

    DOEpatents

    Kaun, T.D.; Eshman, P.F.

    1980-05-09

    A secondary electrochemical cell is prepared by providing positive and negative electrodes having outer enclosures of rigid perforated electrically conductive material defining an internal compartment containing the electrode material in porous solid form. The electrodes are each immersed in molten electrolyte salt prior to cell assembly to incorporate the cell electrolyte. Following solidification of the electrolyte substantially throughout the porous volume of the electrode material, the electrodes are arranged in an alternating positive-negative array with interelectrode separators of porous frangible electrically insulative material. The completed array is assembled into the cell housing and sealed such that on heating the solidified electrolyte flows into the interelectrode separator.

  19. Electrochemical cell

    SciTech Connect

    Moses, P.R.; Berkowitz, F.J.; Taylor, A.H.

    1990-06-26

    This paper describes an electrochemical cell having a spirally wound electrode stack. It comprises: an anode, a cathode, and a separator spirally wound together with the separator positioned between the anode and cathode, whereby an outer segment of the anode lies along the outer circumference of the electrode stack and the remainder of the circumference comprises an outer segment of the cathode, wherein the outer anode segment comprises no more than 10% of the total anode length; and anode tab attached to the inner surface of the outer segment of anode; an electrolyte; an electrically conductive member in mechanical and electrical contact with the outer cathode segment. Said member extends over the outer anode segment and beyond the outer edge thereof; and an insulating means located along the inner surface of the outer anode segment which means is a barrier to ion migration; whereby, during voltage reversal, anode metal is preferentially plated from the outer surface of the outer anode segment to the conductive member juxtaposed thereto.

  20. Electrochemical cell stack assembly

    DOEpatents

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

    2010-06-22

    Multiple stacks of tubular electrochemical cells having a dense electrolyte disposed between an anode and a cathode preferably deposited as thin films arranged in parallel on stamped conductive interconnect sheets or ferrules. The stack allows one or more electrochemical cell to malfunction without disabling the entire stack. Stack efficiency is enhanced through simplified gas manifolding, gas recycling, reduced operating temperature and improved heat distribution.

  1. Separators for electrochemical cells

    DOEpatents

    Carlson, Steven Allen; Anakor, Ifenna Kingsley

    2014-11-11

    Provided are separators for use in an electrochemical cell comprising (a) an inorganic oxide and (b) an organic polymer, wherein the inorganic oxide comprises organic substituents. Preferably, the inorganic oxide comprises an hydrated aluminum oxide of the formula Al.sub.2O.sub.3.xH.sub.2O, wherein x is less than 1.0, and wherein the hydrated aluminum oxide comprises organic substituents, preferably comprising a reaction product of a multifunctional monomer and/or organic carbonate with an aluminum oxide, such as pseudo-boehmite and an aluminum oxide. Also provided are electrochemical cells comprising such separators.

  2. Electrochemical photovoltaic cells

    NASA Astrophysics Data System (ADS)

    Ang, P. G. P.; Tiller, A. J.; Rossignuolo, A. A.; Sammells, A. F.

    1981-04-01

    The photoelectrochemical properties of p-Si, p-InP, p-MoS2, and n-CdSe semiconductors are presented. A number of redox storage systems are discussed. Characteristics of single crystal systems and of surface treatments are investigated. Long term testing was performed with polycrystalline CdSe and with p-InP single crystal in electrochemical cells. The quality and long term stability of various electrodes, electrolytes, and separator materials are studied.

  3. Miniaturized Electrochemical Flow Cells

    PubMed Central

    Sahlin, Eskil; Halle, Alexandra ter; Schaefer, Kathleen; Horn, Jeffery; Then, Matthew; Weber, Stephen G.

    2006-01-01

    Several novel types of miniaturized electrochemical flow cells are described. The flow cells are fabricated in fluorinated ethylene propylene using a novel technique where channels with inner diameters down to 13 ?m are integrated with electrodes. The channel is formed by shrinking and simultaneous melting of a heat shrink/melt tubing around a channel template (a tungsten wire) and electrodes followed by removal of the channel template. The technique allows incorporation of different electrode materials of different sizes. The electrode configuration consists of one or two working electrodes inside the channel and a counter electrode located in the channel outlet reservoir. Electrode configurations with different channel and working electrode sizes, different electrode materials including carbon fibers, glassy carbon rods, poly(tetrafluoroethylene)/carbon composite material, and platinum wires, and different arrangements have been assembled. Hydrodynamic voltammograms in dual-electrode (generator–collector) experiments indicate good potential control for cells with 25-?m channels, while there is some iR drop in cells with 13-?m channels. Cells prepared with a cylindrical working electrode tangent and perpendicular to a flow channel show a flow rate dependence consistent with thin-layer cell behavior. Electrode areas can be made in the range of 10?10–10?8 m2. PMID:12622401

  4. Electrochemical photovoltaic cells and electrodes

    DOEpatents

    Skotheim, Terje A. (East Patchogue, NY)

    1984-01-01

    Improved electrochemical photovoltaic cells and electrodes for use therein, particularly electrodes employing amorphous silicon or polyacetylene coating are produced by a process which includes filling pinholes or porous openings in the coatings by electrochemical oxidation of selected monomers to deposit insulating polymer in the openings.

  5. Thermally-Rechargeable Electrochemical Cell

    NASA Technical Reports Server (NTRS)

    Richter, R.

    1985-01-01

    Proposed liquid-sodium/sulfur electrochemical cell recharged by heat, rather than electric generator. Concept suitable for energy storage for utilites, mobile electronic equipment, and solar thermoelectric power systems. Sodium ions driven across membrane with aid of temperature differential.

  6. Method for manufacturing an electrochemical cell

    DOEpatents

    Kaun, Thomas D. (New Lenox, IL); Eshman, Paul F. (Bolingbrook, IL)

    1982-01-01

    A secondary electrochemical cell is prepared by providing positive and negative electrodes having outer enclosures of rigid perforated electrically conductive material defining an internal compartment containing the electrode material in porous solid form. The electrodes are each immersed in molten electrolyte salt prior to cell assembly to incorporate the cell electrolyte. Following solidification of the electrolyte substantially throughout the porous volume of the electrode material, the electrodes are arranged in an alternating positive-negative array with interelectrode separators of porous frangible electrically insulative material. The completed array is assembled into the cell housing and sealed such that on heating the solidified electrolyte flows into the interelectrode separator.

  7. Electrochemical cell with high conductivity glass electrolyte

    DOEpatents

    Nelson, Paul A. (Wheaton, IL); Bloom, Ira D. (Lisle, IL); Roche, Michael F. (Glen Ellyn, IL)

    1987-01-01

    A secondary electrochemical cell with sodium-sulfur or other molten reactants is provided with a ionically conductive glass electrolyte. The cell is contained within an electrically conductive housing with a first portion at negative potential and a second portion insulated therefrom at positive electrode potential. The glass electrolyte is formed into a plurality of elongated tubes and placed lengthwise within the housing. The positive electrode material, for instance sulfur, is sealed into the glass electrolyte tubes and is provided with an elongated axial current collector. The glass electrolyte tubes are protected by shield tubes or sheets that also define narrow annuli for wicking of the molten negative electrode material.

  8. Electrochemical cell with high conductivity glass electrolyte

    DOEpatents

    Nelson, P.A.; Bloom, I.D.; Roche, M.F.

    1987-04-21

    A secondary electrochemical cell with sodium-sulfur or other molten reactants is provided with a ionically conductive glass electrolyte. The cell is contained within an electrically conductive housing with a first portion at negative potential and a second portion insulated therefrom at positive electrode potential. The glass electrolyte is formed into a plurality of elongated tubes and placed lengthwise within the housing. The positive electrode material, for instance sulfur, is sealed into the glass electrolyte tubes and is provided with an elongated axial current collector. The glass electrolyte tubes are protected by shield tubes or sheets that also define narrow annuli for wicking of the molten negative electrode material. 6 figs.

  9. Electrochemical cell with high conductivity glass electrolyte

    DOEpatents

    Nelson, P.A.; Bloom, I.D.; Roche, M.F.

    1986-04-17

    A secondary electrochemical cell with sodium-sulfur or other molten reactants is provided with an ionically conductive glass electrolyte. The cell is contained within an electrically conductive housing with a first portion at negative potential and a second portion insulated therefrom at positive electrode potential. The glass electrolyte is formed into a plurality of elongated tubes and placed lengthwise within the housing. The positive electrode material, for instance sulfur, is sealed into the glass electrolyte tubes and is provided with an elongated axial current collector. The glass electrolyte tubes are protected by shield tubes or sheets that also define narrow annuli for wicking of the molten negative electrode material.

  10. Separator material for electrochemical cells

    DOEpatents

    Cieslak, Wendy R. (1166 Laurel Loop NE., Albuquerque, NM 87122); Storz, Leonard J. (2215 Ambassador NE., Albuquerque, NM 87112)

    1991-01-01

    An electrochemical cell characterized as utilizing an aramid fiber as a separator material. The aramid fibers are especially suited for lithium/thionyl chloride battery systems. The battery separator made of aramid fibers possesses superior mechanical strength, chemical resistance, and is flame retardant.

  11. Separator material for electrochemical cells

    DOEpatents

    Cieslak, W.R.; Storz, L.J.

    1991-03-26

    An electrochemical cell is characterized as utilizing an aramid fiber as a separator material. The aramid fibers are especially suited for lithium/thionyl chloride battery systems. The battery separator made of aramid fibers possesses superior mechanical strength, chemical resistance, and is flame retardant.

  12. Electrochemical sensor for monitoring electrochemical potentials of fuel cell components

    DOEpatents

    Kunz, Harold R. (Vernon, CT); Breault, Richard D. (Coventry, CT)

    1993-01-01

    An electrochemical sensor comprised of wires, a sheath, and a conduit can be utilized to monitor fuel cell component electric potentials during fuel cell shut down or steady state. The electrochemical sensor contacts an electrolyte reservoir plate such that the conduit wicks electrolyte through capillary action to the wires to provide water necessary for the electrolysis reaction which occurs thereon. A voltage is applied across the wires of the electrochemical sensor until hydrogen evolution occurs at the surface of one of the wires, thereby forming a hydrogen reference electrode. The voltage of the fuel cell component is then determined with relation to the hydrogen reference electrode.

  13. High temperature sealed electrochemical cell

    SciTech Connect

    Valentin Chung, Brice Hoani; Burke, Paul J.; Sadoway, Donald R.

    2015-10-06

    A cell for high temperature electrochemical reactions is provided. The cell includes a container, at least a portion of the container acting as a first electrode. An extension tube has a first end and a second end, the extension tube coupled to the container at the second end forming a conduit from the container to said first end. A second electrode is positioned in the container and extends out of the container via the conduit. A seal is positioned proximate the first end of the extension tube, for sealing the cell.

  14. Compacted carbon for electrochemical cells

    DOEpatents

    Greinke, Ronald Alfred (Medina, OH); Lewis, Irwin Charles (Strongsville, OH)

    1997-01-01

    This invention provides compacted carbon that is useful in the electrode of an alkali metal/carbon electrochemical cell of improved capacity selected from the group consisting of: (a) coke having the following properties: (i) an x-ray density of at least 2.00 grams per cubic centimeters, (ii) a closed porosity of no greater than 5%, and (iii) an open porosity of no greater than 47%; and (b) graphite having the following properties: (i) an x-ray density of at least 2.20 grams per cubic centimeters, (ii) a closed porosity of no greater than 5%, and (iii) an open porosity of no greater than 25%. This invention also relates to an electrode for an alkali metal/carbon electrochemical cell comprising compacted carbon as described above and a binder. This invention further provides an alkali metal/carbon electrochemical cell comprising: (a) an electrode as described above, (b) a non-aqueous electrolytic solution comprising an organic aprotic solvent and an electrolytically conductive salt and an alkali metal, and (c) a counterelectrode.

  15. Compacted carbon for electrochemical cells

    DOEpatents

    Greinke, R.A.; Lewis, I.C.

    1997-10-14

    This invention provides compacted carbon that is useful in the electrode of an alkali metal/carbon electrochemical cell of improved capacity selected from the group consisting of: (a) coke having the following properties: (1) an x-ray density of at least 2.00 grams per cubic centimeters, (2) a closed porosity of no greater than 5%, and (3) an open porosity of no greater than 47%; and (b) graphite having the following properties: (1) an x-ray density of at least 2.20 grams per cubic centimeters, (2) a closed porosity of no greater than 5%, and (3) an open porosity of no greater than 25%. This invention also relates to an electrode for an alkali metal/carbon electrochemical cell comprising compacted carbon as described above and a binder. This invention further provides an alkali metal/carbon electrochemical cell comprising: (a) an electrode as described above, (b) a non-aqueous electrolytic solution comprising an organic aprotic solvent and an electrolytically conductive salt and an alkali metal, and (c) a counter electrode. 10 figs.

  16. Electrochemical cell having cylindrical electrode elements

    DOEpatents

    Nelson, Paul A. (Wheaton, IL); Shimotake, Hiroshi (Hinsdale, IL)

    1982-01-01

    A secondary, high temperature electrochemical cell especially adapted for lithium alloy negative electrodes, transition metal chalcogenide positive electrodes and alkali metal halide or alkaline earth metal halide electrolyte is disclosed. The cell is held within an elongated cylindrical container in which one of the active materials is filled around the outside surfaces of a plurality of perforate tubular current collectors along the length of the container. Each of the current collector tubes contain a concentric tubular layer of electrically insulative ceramic as an interelectrode separator. The active material of opposite polarity in elongated pin shape is positioned longitudinally within the separator layer. A second electrically conductive tube with perforate walls can be swagged or otherwise bonded to the outer surface of the pin as a current collector and the electrically insulative ceramic layer can be coated or otherwise layered onto the outer surface of this second current collector. Alternatively, the central pin electrode can include an axial core as a current collector.

  17. Bussing Structure In An Electrochemical Cell

    DOEpatents

    Romero, Antonio L. (Parkton, MD)

    2001-06-12

    A bussing structure for bussing current within an electrochemical cell. The bussing structure includes a first plate and a second plate, each having a central aperture therein. Current collection tabs, extending from an electrode stack in the electrochemical cell, extend through the central aperture in the first plate, and are then sandwiched between the first plate and second plate. The second plate is then connected to a terminal on the outside of the case of the electrochemical cell. Each of the first and second plates includes a second aperture which is positioned beneath a safety vent in the case of the electrochemical cell to promote turbulent flow of gasses through the vent upon its opening. The second plate also includes protrusions for spacing the bussing structure from the case, as well as plateaus for connecting the bussing structure to the terminal on the case of the electrochemical cell.

  18. Electrochemical cell having an alkali-metal-nitrate electrode

    SciTech Connect

    Roche, M.F.; Preto, S.K.

    1982-06-04

    A power-producing secondary electrochemical cell includes a molten alkali metal as the negative-electrode material and a molten-nitrate salt as the positive-electrode material. The molten material in the respective electrodes are separated by a solid barrier of alkali-metal-ion conducting material. A typical cell includes active materials of molten sodium separated from molten sodium nitrate and other nitrates in mixture by a layer of sodium ..beta..'' alumina.

  19. Thermodynamics of Electrochemical Cells Chemistry 223

    E-print Network

    Ronis, David M.

    discussion to reversible cells, in which case Eq.(2) becomes an equality. Notice that the cell EMF as the electromotive force or EMF. Fall Term, 2014 #12;Thermodynamics of Electrochemical Cells -3- Chemistry 223, the overall cell EMF is 0. 337 - (0. 763) = 1. 100V and the cell operates as written. Note that the standard

  20. Chemically modified graphite for electrochemical cells

    DOEpatents

    Greinke, Ronald Alfred (Medina, OH); Lewis, Irwin Charles (Strongsville, OH)

    1998-01-01

    This invention relates to chemically modified graphite particles: (a) that are useful in alkali metal-containing electrode of a electrochemical cell comprising: (i) the electrode, (ii) a non-aqueous electrolytic solution comprising an organic aprotic solvent which solvent tends to decompose when the electrochemical cell is in use, and an electrically conductive salt of an alkali metal, and (iii) a counterelectrode; and (b) that are chemically modified with fluorine, chlorine, iodine or phosphorus to reduce such decomposition. This invention also relates to electrodes comprising such chemically modified graphite and a binder and to electrochemical cells containing such electrodes.

  1. Chemically modified graphite for electrochemical cells

    DOEpatents

    Greinke, R.A.; Lewis, I.C.

    1998-05-26

    This invention relates to chemically modified graphite particles: (a) that are useful in alkali metal-containing electrode of a electrochemical cell comprising: (1) the electrode, (2) a non-aqueous electrolytic solution comprising an organic aprotic solvent which solvent tends to decompose when the electrochemical cell is in use, and an electrically conductive salt of an alkali metal, and (3) a counter electrode; and (b) that are chemically modified with fluorine, chlorine, iodine or phosphorus to reduce such decomposition. This invention also relates to electrodes comprising such chemically modified graphite and a binder and to electrochemical cells containing such electrodes. 3 figs.

  2. Boundary Layer Analysis of Membraneless Electrochemical Cells

    E-print Network

    Braff, William

    A mathematical theory is presented for the charging and discharging behavior of membraneless electrochemical cells that rely on slow diffusion in laminar flow to separate the half reactions. Ion transport is described by ...

  3. Advances in ambient temperature secondary lithium cells

    NASA Technical Reports Server (NTRS)

    Subbarao, S.; Shen, D. H.; Deligiannis, F.; Huang, C-K.; Halpert, G.

    1989-01-01

    The goal is to develop secondary lithium cells with a 100 Wh/kg specific energy capable of 1000 cycles at 50 percent DOD. The approach towards meeting this goal initially focused on several basic issues related to the cell chemistry, selection of cathode materials and electrolytes and component development. The performance potential of Li-TiS2, Li-MoS3, Li-V6O13 and Li-NbSe3 electrochemical systems was examined. Among these four, the Li-TiS2 system was found to be the most promising system in terms of achievable specific energy and cycle life. Major advancements to date in the development of Li-TiS2 cells are in the areas of cathode processing technology, mixed solvent electrolytes, and cell assembly. A summary is given of these advances.

  4. Refractory lining for electrochemical cell

    DOEpatents

    Blander, Milton (Palos Park, IL); Cook, Glenn M. (Naperville, IL)

    1987-01-01

    Apparatus for processing a metallic fluid containing iron oxide, container for a molten metal including an electrically conductive refractory disposed for contact with the molten metal which contains iron oxide, an electrolyte in the form of a basic slag on top of the molten metal, an electrode in the container in contcat with the slag electrically separated from the refractory, and means for establishing a voltage across the refractory and the electrode to reduce iron oxide to iron at the surface of the refractory in contact with the iron oxide containing fluid. A process is disclosed for refining an iron product containing not more than about 10% by weight oxygen and not more than about 10% by weight sulfur, comprising providing an electrolyte of a slag containing one or more of calcium oxide, magnesium oxide, silica or alumina, providing a cathode of the iron product in contact with the electrolyte, providing an anode in contact with the electrolyte electrically separated from the cathode, and operating an electrochemical cell formed by the anode, the cathode and the electrolyte to separate oxygen or sulfur present in the iron product therefrom.

  5. Nanodisperse transition metal electrodes (NTME) for electrochemical cells

    SciTech Connect

    Striebel, Kathryn A.; Wen, Shi-Jie

    1998-12-01

    Disclosed are transition metal electrodes for electrochemical cells using gel-state and solid-state polymers. The electrodes are suitable for use in primary and secondary cells. The electrodes (either negative electrode or positive electrode) are characterized by uniform dispersion of the transition metal at the nanoscale in the polymer. The transition metal moiety is structurally amorphous, so no capacity fade should occur due to lattice expansion/contraction mechanisms. The small grain size, amorphous structure and homogeneous distribution provide improved charge/discharge cycling performance, and a higher initial discharge rate capability. The cells can be cycled at high current densities, limited only by the electrolyte conductivity. A method of making the electrodes (positive and negative), and their usage in electrochemical cells are disclosed.

  6. Nanodisperse transition metal electrodes (NTME) for electrochemical cells

    DOEpatents

    Striebel, Kathryn A. (Oakland, CA); Wen, Shi-Jie (Sunnyvale, CA)

    2000-01-01

    Disclosed are transition metal electrodes for electrochemical cells using gel-state and solid-state polymers. The electrodes are suitable for use in primary and secondary cells. The electrodes (either negative electrode or positive electrode) are characterized by uniform dispersion of the transition metal at the nanoscale in the polymer. The transition metal moiety is structurally amorphous, so no capacity fade should occur due to lattice expansion/contraction mechanisms. The small grain size, amorphous structure and homogeneous distribution provide improved charge/discharge cycling performance, and a higher initial discharge rate capability. The cells can be cycled at high current densities, limited only by the electrolyte conductivity. A method of making the electrodes (positive and negative), and their usage in electrochemical cells are disclosed.

  7. Textbook Error: Short Circuiting on Electrochemical Cell

    ERIC Educational Resources Information Center

    Bonicamp, Judith M.; Clark, Roy W.

    2007-01-01

    Short circuiting an electrochemical cell is an unreported but persistent error in the electrochemistry textbooks. It is suggested that diagrams depicting a cell delivering usable current to a load be postponed, the theory of open-circuit galvanic cells is explained, the voltages from the tables of standard reduction potentials is calculated and…

  8. An electrochemical rebalance cell for Redox systems

    NASA Technical Reports Server (NTRS)

    Acevedo, J. C.; Stalnaker, D. K.

    1983-01-01

    An electrochemical rebalance cell for maintaining electrochemical balance, at the system level, of the acidified aqueous iron chloride and chromium chloride reactant solutions in the redox energy storage system was constructed and evaluated. The electrochemical reaction for the cathode is Fe(+3) + e(-) yields Fe(+2), and that for the anode is 1/2H2 yields H(+) + e(-). The iron (carbon felt) electrode and the hydrogen (platinized carbon) electrode are separated by an anion exchange membrane. The performance of the rebalance cell is discussed as well as the assembly of a single rebalance cell and multicell stacks. Various cell configurations were tested and the results are presented and discussed. The rebalance cell was also used to demonstrate its ability, as a preparative tool, for making high purity solutions of soluble reduced metal ionic species. Preparations of titanium, copper, vanadium and chromium ions in acidified solutions were evaluated.

  9. Gas recombination assembly for electrochemical cells

    DOEpatents

    Levy, Isaac (New Fairfield, CT); Charkey, Allen (Brookfield, CT)

    1989-01-01

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

  10. Heteroatom incorporated coke for electrochemical cell electrode

    DOEpatents

    Lewis, Irwin Charles (Strongsville, OH); Greinke, Ronald Alfred (Medina, OH)

    1997-01-01

    This invention relates to an electrode for a coke/alkali metal electrochemical cell comprising: (a) calcined coke particles: (i) that contain at least 0.5 weight percent of nitrogen heteroatoms and at least 1.0 weight percent sulfur heteroatoms, and (ii) that have an average particle size from 2 microns to 40 microns with essentially no particles being greater than 50 microns. (b) a binder This invention also relates to a coke/alkali metal electrochemical cell comprising: (a) an electrode as described above, (b) a non-aqueous electrolytic solution comprising an organic aprotic solvent and an electrically conductive salt, and (c) a counterelectrode.

  11. Heteroatom incorporated coke for electrochemical cell electrode

    SciTech Connect

    Lewis, I.C.; Greinke, R.A.

    1997-06-17

    This invention relates to an electrode for a coke/alkali metal electrochemical cell comprising: (a) calcined coke particles: (1) that contain at least 0.5 weight percent of nitrogen heteroatoms and at least 1.0 weight percent sulfur heteroatoms, and (2) that have an average particle size from 2 microns to 40 microns with essentially no particles being greater than 50 microns and (b) a binder. This invention also relates to a coke/alkali metal electrochemical cell comprising: (a) an electrode as described above, (b) a non-aqueous electrolytic solution comprising an organic aprotic solvent and an electrically conductive salt, and (c) a counterelectrode. 5 figs.

  12. Highly Sensitive Bacteria Quantification Using Immunomagnetic Separation and Electrochemical Detection of Guanine-Labeled Secondary Beads

    PubMed Central

    Jayamohan, Harikrishnan; Gale, Bruce K.; Minson, Bj; Lambert, Christopher J.; Gordon, Neil; Sant, Himanshu J.

    2015-01-01

    In this paper, we report the ultra-sensitive indirect electrochemical detection of E. coli O157:H7 using antibody functionalized primary (magnetic) beads for capture and polyguanine (polyG) oligonucleotide functionalized secondary (polystyrene) beads as an electrochemical tag. Vacuum filtration in combination with E. coli O157:H7 specific antibody modified magnetic beads were used for extraction of E. coli O157:H7 from 100 mL samples. The magnetic bead conjugated E. coli O157:H7 cells were then attached to polyG functionalized secondary beads to form a sandwich complex (magnetic bead/E. coli/ secondary bead). While the use of magnetic beads for immuno-based capture is well characterized, the use of oligonucleotide functionalized secondary beads helps combine amplification and potential multiplexing into the system. The antibody functionalized secondary beads can be easily modified with a different antibody to detect other pathogens from the same sample and enable potential multiplexing. The polyGs on the secondary beads enable signal amplification up to 108 guanine tags per secondary bead (7.5 × 106 biotin-FITC per secondary bead, 20 guanines per oligonucleotide) bound to the target (E. coli). A single-stranded DNA probe functionalized reduced graphene oxide modified glassy carbon electrode was used to bind the polyGs on the secondary beads. Fluorescent imaging was performed to confirm the hybridization of the complex to the electrode surface. Differential pulse voltammetry (DPV) was used to quantify the amount of polyG involved in the hybridization event with tris(2,2?-bipyridine)ruthenium(II) ( Ru(bpy)32+) as the mediator. The amount of polyG signal can be correlated to the amount of E. coli O157:H7 in the sample. The method was able to detect concentrations of E. coli O157:H7 down to 3 CFU/100 mL, which is 67 times lower than the most sensitive technique reported in literature. The signal to noise ratio for this work was 3. We also demonstrate the use of the protocol for detection of E. coli O157:H7 seeded in waste water effluent samples. PMID:26007743

  13. Alkaline electrochemical cells and method of making

    NASA Technical Reports Server (NTRS)

    Hoyt, H. E.; Pfluger, H. L. (inventors)

    1970-01-01

    Equilibrated cellulose ether membranes of increased electrolytic conductivity for use as separators in concentrated alkaline electrochemical cells are investigated. The method of making such membranes by equilibration to the degree desired in an aqueous alkali solution mantained at a temperature below about 10 C is described.

  14. Minimizing electrode contamination in an electrochemical cell

    DOEpatents

    Kim, Yu Seung; Zelenay, Piotr; Johnston, Christina

    2014-12-09

    An electrochemical cell assembly that is expected to prevent or at least minimize electrode contamination includes one or more getters that trap a component or components leached from a first electrode and prevents or at least minimizes them from contaminating a second electrode.

  15. Method of constructing an improved electrochemical cell

    DOEpatents

    Grimes, Patrick G. (Westfield, NJ); Einstein, Harry (Springfield, NJ)

    1984-10-09

    An electrochemical cell construction features a novel co-extruded plastic electrode in an interleaved construction with a novel integral separator-spacer. Also featured is a leak and impact resistant construction for preventing the spill of corrosive materials in the event of rupture.

  16. Electrolyte for an electrochemical cell

    DOEpatents

    Bates, J.B.; Dudney, N.J.

    1997-01-28

    Described is a thin-film battery, especially a thin-film microbattery, and a method for making the same having application as a backup or primary integrated power source for electronic devices. The battery includes a novel electrolyte amorphous lithium phosphorus oxynitride which is electrochemically stable and does not react with the lithium anode and a novel vanadium oxide cathode Configured as a microbattery, the battery can be fabricated directly onto a semiconductor chip, onto the semiconductor die or onto any portion of the chip carrier. The battery can be fabricated to any specified size or shape to meet the requirements of a particular application. The battery is fabricated of solid state materials and is capable of operation between {minus}15 C and 150 C. 9 figs.

  17. Electrolyte for an electrochemical cell

    DOEpatents

    Bates, John B. (Oak Ridge, TN); Dudney, Nancy J. (Knoxville, TN)

    1997-01-01

    Described is a thin-film battery, especially a thin-film microbattery, and a method for making same having application as a backup or primary integrated power source for electronic devices. The battery includes a novel electrolyte amorphous lithium phosphorus oxynitride which is electrochemically stable and does not react with the lithium anode and a novel vanadium oxide cathode Configured as a microbattery, the battery can be fabricated directly onto a semiconductor chip, onto the semiconductor die or onto any portion of the chip carrier. The battery can be fabricated to any specified size or shape to meet the requirements of a particular application. The battery is fabricated of solid state materials and is capable of operation between -15.degree. C. and 150.degree. C.

  18. Cathode for an electrochemical cell

    DOEpatents

    Bates, John B. (Oak Ridge, TN); Dudney, Nancy J. (Knoxville, TN); Gruzalski, Greg R. (Oak Ridge, TN); Luck, Christopher F. (Knoxville, TN)

    2001-01-01

    Described is a thin-film battery, especially a thin-film microbattery, and a method for making same having application as a backup or primary integrated power source for electronic devices. The battery includes a novel electrolyte which is electrochemically stable and does not react with the lithium anode and a novel vanadium oxide cathode. Configured as a microbattery, the battery can be fabricated directly onto a semiconductor chip, onto the semiconductor die or onto any portion of the chip carrier. The battery can be fabricated to any specified size or shape to meet the requirements of a particular application. The battery is fabricated of solid state materials and is capable of operation between -15.degree. C. and 150.degree. C.

  19. Electrochemical Cells with Intermediate Capacitor Elements

    E-print Network

    Grebel, Haim

    2015-01-01

    Our goal is to electronically regulate electrochemical cells. For this, we introduced a third element, called the gate, which was placed between the cathode and the anode electrodes of the cell. Voltage applied to this element controlled the local potential of the electrolyte, thus impacting the flow of ions within the cell. The flow of ions was monitored by the electronic current in the external cell's circuit. We provide simulations and experimental data as proof to the validity of this concept. This is but the first step towards a demonstration of a two-dimensional, bi-carrier ion transistors.

  20. Electrochemical cells with intermediate capacitor elements

    NASA Astrophysics Data System (ADS)

    Grebel, Haim; Patel, Akshat

    2015-11-01

    Our goal is to electronically regulate electrochemical cells. For this, we introduced a third element, called the gate, which was placed between the cathode and the anode electrodes of the cell. Voltage applied to this element controlled the electronic current in the external circuit. The change in the cell's current was attributed to local change in the electrolyte potential, which impacted the flow of ions within the cell. We provide simulations and experimental data as a proof of concept. This is but the first step toward a demonstration of a two-dimensional, bi-carrier ion transistors.

  1. Secondary anchor targeted cell release.

    PubMed

    Ansari, Ali; Lee-Montiel, Felipe T; Amos, Jennifer R; Imoukhuede, P I

    2015-11-01

    Personalized medicine offers the promise of tailoring therapy to patients, based on their cellular biomarkers. To achieve this goal, cellular profiling systems are needed that can quickly and efficiently isolate specific cell types without disrupting cellular biomarkers. Here we describe the development of a unique platform that facilitates gentle cell capture via a secondary, surface-anchoring moiety, and cell release. The cellular capture system consists of a glass surface functionalized with APTES, d-desthiobiotin, and streptavidin. Biotinylated mCD11b and hIgG antibodies are used to capture mouse macrophages (RAW 264.7) and human breast cancer (MCF7-GFP) cell lines, respectively. The surface functionalization is optimized by altering assay components, such as streptavidin, d-desthiobiotin, and APTES, to achieve cell capture on 80% of the functionalized surface and cell release upon biotin treatment. We also demonstrate an ability to capture 50% of target cells within a dual-cell mixture. This engineering advancement is a critical step towards achieving cell isolation platforms for personalized medicine. Biotechnol. Bioeng. 2015;112: 2214-2227. © 2015 Wiley Periodicals, Inc. PMID:26010879

  2. Electrochemical characteristics of lithium-ion cells

    SciTech Connect

    Nagasubramanian, C.; Roth, P.; Jungst, R.G.; Clark, N.

    1998-01-01

    The authors describe below the electrochemical performance characteristics, including charge-discharge characteristics at different rates, of cylindrical 18650 (18 mm diameter, 65 mm high) and prismatic lithium ion cells at ambient and sub-ambient temperatures. Ragone plots of power and energy data for these cells are compared and indicate that at room temperature the prismatic lithium ion cells (approx. 500 mAh) exhibit higher specific power and power density than the 18650 cells (approx. 1,100 mAhr). The cell impedance was measured between 35 C and {minus}40 C at three open circuit voltages: 4.1 v (fully charged), 3.6 v (partially discharged), and 3.1 v (almost completely discharged). Over the temperature range from 35 C to {minus}20 C, the cell impedance is nearly constant for both cell types and increases by 2 to 3 times at {minus}40 C. The impedance doesn`t vary significantly with open circuit voltage (OCV). These cells show very little voltage drop at room temperature for current pulses up to 1 A. The charge-discharge characteristics of the cells are being studied at different rates as a function of temperature to compute the power, energy, and capacity outputs. This will not only broaden the database on lithium ion cells, but will also allow us to evaluate the suitability of the cells as power sources for low temperature applications. Other electrochemical characteristics of these cells including pulse response are being evaluated. Impedance measurements of the cells under load are planned to make meaningful correlations between the voltage drop and the current pulse amplitude.

  3. High energy density electrochemical cell

    NASA Technical Reports Server (NTRS)

    Byrne, J. J.; Williams, D. L.

    1970-01-01

    Primary cell has an anode of lithium, a cathode containing dihaloisocyanuric acid, and a nonaqueous electrolyte comprised of a solution of lithium perchlorate in methyl formate. It produces an energy density of 213 watt hrs/lb and can achieve a high current density.

  4. Electrochemical cell having internal short inhibitor

    SciTech Connect

    Hooke, J.W.

    1984-04-24

    An electrochemical cell comprises a spirally wound assembly, the assembly including a negative plate; a porous polyester layer disposed on each major surface of the negative plate; a porous, electrically non-conductive separator disposed on each of the polyester layers; and a positive plate disposed on one of the separators. The cell further includes a housing for enclosing the assembly and an electrolyte such that the electrolyte comes in contact with the plates, polyester layers and separators. The housing includes a pair of external terminals each of which being connected to one of the plates.

  5. Electrochemical Cell Design With A Hollow Gate

    DOEpatents

    Romero, Antonio (Parkton, MD); Oweis, Salah (Ellicott City, MD); Chagnon, Guy (Columbia, MD); Staniewicz, Robert (Hunt Valley, MD); Briscoe, Douglas (Westminster, MD)

    2000-02-01

    An electrochemical cell having a spiral winding around a central core, wherein the central core is provided with longitudinal grooves on its outer surface to facilitate electrolyte filing and accommodate overpressure. The core itself improves dissipation of heat generated along the center of the cell, and the hollow core design allows the cell core to have a larger radius, permitting the "jelly roll" winding to begin at a larger radius and thereby facilitate the initial turns of the winding by decreasing the amount of bending required of the electrode laminate at the beginning of the winding operation. The hollow core also provides mechanical support end-to-end. A pair of washers are used at each end of the cell to sandwich current collection tabs in a manner that improves electrical and thermal conductivity while also providing structural integrity.

  6. Cycle life test. [of secondary spacecraft cells

    NASA Technical Reports Server (NTRS)

    Harkness, J. D.

    1977-01-01

    Statistical information concerning cell performance characteristics and limitations of secondary spacecraft cells is presented. Weaknesses in cell design as well as battery weaknesses encountered in various satellite programs are reported. Emphasis is placed on improving the reliability of space batteries.

  7. Solid oxide electrochemical cell fabrication process

    DOEpatents

    Dollard, Walter J. (Churchill Borough, PA); Folser, George R. (Lower Burrell, PA); Pal, Uday B. (Cambridge, MA); Singhal, Subhash C. (Murrysville, PA)

    1992-01-01

    A method to form an electrochemical cell (12) is characterized by the steps of thermal spraying stabilized zirconia over a doped lanthanum manganite air electrode tube (14) to provide an electrolyte layer (15), coating conductive particles over the electrolyte, pressurizing the outside of the electrolyte layer, feeding halide vapors of yttrium and zirconium to the outside of the electrolyte layer and feeding a source of oxygen to the inside of the electrolyte layer, heating to cause oxygen reaction with the halide vapors to close electrolyte pores if there are any and to form a metal oxide coating on and between the particles and provide a fuel electrode (16).

  8. Cogeneration with Thermionics and Electrochemical Cells 

    E-print Network

    Miskolczy, G.; Goodale, D.; Huffman, F.; Morgan, D.

    1984-01-01

    the Sixth Annual Industrial Energy Technology Conference Volume II, Houston, TX, April 15-18, 1984 COG8NERATION WITH TH8RMIONICS ANI) ELECTROCHEMICAL CELLS? Gabor MisKolczy, Douglass Goodale, Fred Huffman and Dean Morgan Thermo Electron Corporation Waltham...-18, 1984 REFEI{ENCES [3] D. Goodale. P. Reagan. D. Lieb, F. Huffman, "Thermionic Converter for Terrestrial Application ," Proc. 17th IECEC. 1982. pp, 1913-1917. [I] G. Miskolczy, C.C. Wang, D.P. Lieb, A.E. Margulies, L.J. Fusegni, B.J. Lovell, "Thermionic...

  9. Sensor apparatus using an electrochemical cell

    DOEpatents

    Thakur, Mrinal (1309 Gatewood Dr., Apt. 1703, Auburn, AL 36830)

    2002-01-01

    A novel technology for sensing mechanical quantities such as force, stress, strain, pressure and acceleration has been invented. This technology is based on a change in the electrochemically generated voltage (electromotive force) with application of force, stress, strain, pressure or acceleration. The change in the voltage is due to a change in the internal resistance of the electrochemical cell with a change in the relative position or orientation of the electrodes (anode and cathode) in the cell. The signal to be detected (e.g. force, stress, strain, pressure or acceleration) is applied to one of the electrodes to cause a change in the relative position or orientation between the electrodes. Various materials, solid, semisolid, gel, paste or liquid can be utilized as the electrolyte. The electrolyte must be an ion conductor. The examples of solid electrolytes include specific polymer conductors, polymer composites, ion conducting glasses and ceramics. The electrodes are made of conductors such as metals with dissimilar electronegativities. Significantly enhanced sensitivities, up to three orders of magnitude higher than that of comparable commercial sensors, are obtained. The materials are substantially less expensive than commercially used materials for mechanical sensors.

  10. Sensor apparatus using an electrochemical cell

    DOEpatents

    Thakur, Mrinal

    2003-07-01

    A method for sensing mechanical quantities such as force, stress, strain, pressure and acceleration is disclosed. This technology is based on a change in the electrochemically generated voltage (electromotive force) with application of force, stress, strain, pressure or acceleration. The change in the voltage is due to a change in the internal resistance of the electrochemical cell with a change in the relative position or orientation of the electrodes (anode and cathode) in the cell. The signal to be detected (e.g. force, stress, strain, pressure or acceleration) is applied to one of the electrodes to cause a change in the relative position or orientation between the electrodes. Various materials, solid, semisolid, gel, paste or liquid can be utilized as the electrolyte. The electrolyte must be an ion conductor. The examples of solid electrolytes include specific polymer conductors, polymer composites, ion conducting glasses and ceramics. The electrodes are made of conductors such as metals with dissimilar electro negativities. Significantly enhanced sensitivities, up to three orders of magnitude higher than that of comparable commercial sensors, are obtained. The materials are substantially less expensive than commercially used materials for mechanical sensors. An apparatus for sensing such mechanical quantities using materials such as doped 1,4 cis-polyisopropene and nafion. The 1,4 cis-polyisopropene may be doped with lithium perchlorate or iodine. The output voltage signal increases with an increase of the sensing area for a given stress. The device can be used as an intruder alarm, among other applications.

  11. A Model Approach to the Electrochemical Cell: An Inquiry Activity

    ERIC Educational Resources Information Center

    Cullen, Deanna M.; Pentecost, Thomas C.

    2011-01-01

    In an attempt to address some student misconceptions in electrochemistry, this guided-inquiry laboratory was devised to give students an opportunity to use a manipulative that simulates the particulate-level activity within an electrochemical cell, in addition to using an actual electrochemical cell. Students are led through a review of expected…

  12. Thermodynamic and Kinetic Properties of the Electrochemical Cell.

    ERIC Educational Resources Information Center

    Smith, Donald E.

    1983-01-01

    Describes basic characteristics of the electrochemical cell. Also describes basic principles of electrochemical procedures and use of these concepts to explain use of the term "primarily" in discussions of methods primarily responsive to equilibrium cell potential, bulk ohmic resistance, and the Faradaic impedance. (JN)

  13. Thermal regeneration of an electrochemical concentration cell

    DOEpatents

    Krumpelt, Michael (Naperville, IL); Bates, John K. (Plainfield, IL)

    1981-01-01

    A system and method for thermally regenerating an electrochemical concentration cell having first and second aluminum electrodes respectively positioned in contact with first and second electrolytes separated by an ion exchange member, the first and second electrolytes being composed of different concentrations of an ionic solvent and a salt, preferably an aluminum halide. The ionic solvent may be either organic or inorganic with a relatively low melting point, the ionic solvent and the salt form a complex wherein the free energy of formation of said complex is less than about -5 Kcal/mole. A distillation column using solar heat or low grade industrial waste heat receives the first and second electrolytes and thermally decomposes the salt-solvent complex to provide feed material for the two half cells.

  14. Thermal regeneration of an electrochemical concentration cell

    DOEpatents

    Krumpelt, M.; Bates, J.K.

    1980-05-09

    A system and method are described for thermally regenerating an electrochemical concentration cell having first and second aluminum electrodes respectively positioned in contact with first and second electrolytes separated by an ion exchange member, the first and second electrolytes being composed of different concentrations of an ionic solvent and a salt, preferably an aluminum halide. The ionic solvent may be either organic or inorganic with a relatively low melting point, the ionic solvent and the salt form a complex wherein the free energy of formation of said complex is less than about -5 kcal/mole. A distillation column using solar heat or low grade industrial waste heat receives the first and second electrolytes and thermally decomposes the salt-solvent complex to provide feed material for the two half cells.

  15. A high temperature molten salt thermal electrochemical cell

    NASA Astrophysics Data System (ADS)

    Plichta, Edward J.; Behl, Wishvender K.

    1990-02-01

    This invention relates in general to a high temperature molten salt thermal electrochemical cell and in particular to such a cell including cobalt oxide (Co3O4) as the cathode material. High temperature molten salt thermal electrochemical cells are widely used as power sources for projectiles, rockets, bombs, mines, missiles, decoys, jammers, and torpedoes. These are also used as fuses. Thermal electrochemical cells are reserve-type cells that can be activated by heating with a pyrotechnic heat source such as zirconium and barium chromate powders or mixtures of iron powder and potassium perchlorate.

  16. High-temperature molten-salt thermal electrochemical cell

    SciTech Connect

    Plichta, E.J.; Behl, W.K.

    1990-02-12

    This invention relates in general to a high temperature molten salt thermal electrochemical cell and in particular to such a cell including cobalt oxide (Co{sub 3}O{sub 4}) as the cathode material. High temperature molten salt thermal electrochemical cells are widely used as power sources for projectiles, rockets, bombs, mines, missiles, decoys, jammers and torpedoes. These are also used as fuses. Thermal electrochemical cells are reserve-type cells that can be activated by heating with a pyrotechnic heat source such as zirconium and barium chromate powders or mixtures of iron powder and potassium perchlorate.

  17. Fuel Cell/Electrochemical Cell Voltage Monitor

    NASA Technical Reports Server (NTRS)

    Vasquez, Arturo

    2012-01-01

    A concept has been developed for a new fuel cell individual-cell-voltage monitor that can be directly connected to a multi-cell fuel cell stack for direct substack power provisioning. It can also provide voltage isolation for applications in high-voltage fuel cell stacks. The technology consists of basic modules, each with an 8- to 16-cell input electrical measurement connection port. For each basic module, a power input connection would be provided for direct connection to a sub-stack of fuel cells in series within the larger stack. This power connection would allow for module power to be available in the range of 9-15 volts DC. The relatively low voltage differences that the module would encounter from the input electrical measurement connection port, coupled with the fact that the module's operating power is supplied by the same substack voltage input (and so will be at similar voltage), provides for elimination of high-commonmode voltage issues within each module. Within each module, there would be options for analog-to-digital conversion and data transfer schemes. Each module would also include a data-output/communication port. Each of these ports would be required to be either non-electrical (e.g., optically isolated) or electrically isolated. This is necessary to account for the fact that the plurality of modules attached to the stack will normally be at a range of voltages approaching the full range of the fuel cell stack operating voltages. A communications/ data bus could interface with the several basic modules. Options have been identified for command inputs from the spacecraft vehicle controller, and for output-status/data feeds to the vehicle.

  18. Sampling dynamics for pressurized electrochemical cells

    SciTech Connect

    Eric J. Dufek; Tedd E. Lister; Simon G. Stone

    2014-07-01

    A model describing the gas distribution within a constant pressure electrolysis system and how the distribution impacts electrochemical efficiencies is presented. The primary system of interest is the generation of syngas (CO and H2) associated with the co-electrolysis of H2O and CO2. The model developed for this system takes into account the primary process variables of operation including total system pressure, applied current, the in-flow of reactant gases. From these, and the chemical equilibria within the system, the impact on electrochemically generated gases is presented. Comparing the predicted and measured faradaic efficiency of electrode processes with the expected efficiency from experimental data indicates an offset between the two exists. Methods to minimize and account for the discrepancy are presented with the goal of being able to discern, in a real time manner, degradation of electrode performance. Comparison of the model to experimental data shows a strong correlation between the two with slight variation in experimental data which is attributed to reversible system dynamics such as wetting of the gas diffusion electrode used as the cell cathode.

  19. Electrochemical cells for medium- and large-scale energy storage

    SciTech Connect

    Wang, Wei; Wei, Xiaoliang; Choi, Daiwon; Lu, Xiaochuan; Yang, G.; Sun, C.

    2014-12-12

    This is one of the chapters in the book titled “Advances in batteries for large- and medium-scale energy storage: Applications in power systems and electric vehicles” that will be published by the Woodhead Publishing Limited. The chapter discusses the basic electrochemical fundamentals of electrochemical energy storage devices with a focus on the rechargeable batteries. Several practical secondary battery systems are also discussed as examples

  20. Composite electrode for use in electrochemical cells

    DOEpatents

    Vanderborgh, N.E.; Huff, J.R.; Leddy, J.

    1987-10-16

    A porous composite electrode for use in electrochemical cells. The electrode has a first face and a second face defining a relatively thin section therebetween. The electrode is comprised of an ion conducting material, an electron conducting material, and an electrocatalyst. The volume concentration of the ion conducting material is greatest at the first face and is decreased across the section, while the volume concentration of the electron conducting material is greatest at the second face and decreases across the section of the electrode. Substantially all of the electrocatalyst is positioned within the electrode section in a relatively narrow zone where the rate of electron transport of the electrode is approximately equal to the rate of ion transport of the electrode. 4 figs., 1 tab.

  1. Graphene nanocomposites for electrochemical cell electrodes

    DOEpatents

    Zhamu, Aruna; Jang, Bor Z.; Shi, Jinjun

    2015-11-19

    A composite composition for electrochemical cell electrode applications, the composition comprising multiple solid particles, wherein (a) a solid particle is composed of graphene platelets dispersed in or bonded by a first matrix or binder material, wherein the graphene platelets are not obtained from graphitization of the first binder or matrix material; (b) the graphene platelets have a length or width in the range of 10 nm to 10 .mu.m; (c) the multiple solid particles are bonded by a second binder material; and (d) the first or second binder material is selected from a polymer, polymeric carbon, amorphous carbon, metal, glass, ceramic, oxide, organic material, or a combination thereof. For a lithium ion battery anode application, the first binder or matrix material is preferably amorphous carbon or polymeric carbon. Such a composite composition provides a high anode capacity and good cycling response. For a supercapacitor electrode application, the solid particles preferably have meso-scale pores therein to accommodate electrolyte.

  2. Electrochemical concentration cell ozonesonde accuracy and precision

    NASA Technical Reports Server (NTRS)

    Barnes, R. A.; Bandy, A. R.; Torres, A. L.

    1985-01-01

    This paper is concerned with the results of a study designed to evaluate experimentally the accuracy and precision of electrochemical concentration cell (ECC) ozonesondes as prepared and flown by NASA, as a function of altitude. A combination of dual-instrument soundings and laboratory work using an environmental chamber was employed in the study. The ECC ozonesonde is a small, balloon-borne sensor developed for obtaining vertical profiles of atmospheric ozone. Attention is given to the design of the employed environmental chamber, ozone and temperature profiles used in simulated ozonesonde soundings, absolute and relative ECC ozonesonde precision estimates determined with the environmental chamber and from dual-instrument balloon soundings, and the ECC ozonesonde accuracy.

  3. Electrochemical Cell with Improved Water or Gas Management

    NASA Technical Reports Server (NTRS)

    Smith, William F. (Inventor); McElroy, James F. (Inventor); LaGrange, Jay W. (Inventor)

    2015-01-01

    An electrochemical cell having a water/gas porous separator prepared from a polymeric material and one or more conductive cell components that pass through, or are located in close proximity to, the water/gas porous separator, is provided. The inventive cell provides a high level of in-cell electrical conductivity.

  4. Carbon Nanotubes-Based Electrochemical Sensing for Cell Culture Monitoring

    E-print Network

    De Micheli, Giovanni

    Carbon Nanotubes-Based Electrochemical Sensing for Cell Culture Monitoring Cristina Boero, Sandro different presented strategies to develop biosensors, carbon nanotubes exhibit great properties, particularly suitable for biosensing. In this work nanostructured electrodes by using multi-walled carbon

  5. Electrochemical cells and methods of manufacturing the same

    DOEpatents

    Bazzarella, Ricardo; Slocum, Alexander H; Doherty, Tristan; Cross, III, James C

    2015-11-03

    Electrochemical cells and methods of making electrochemical cells are described herein. In some embodiments, an apparatus includes a multi-layer sheet for encasing an electrode material for an electrochemical cell. The multi-layer sheet including an outer layer, an intermediate layer that includes a conductive substrate, and an inner layer disposed on a portion of the conductive substrate. The intermediate layer is disposed between the outer layer and the inner layer. The inner layer defines an opening through which a conductive region of the intermediate layer is exposed such that the electrode material can be electrically connected to the conductive region. Thus, the intermediate layer can serve as a current collector for the electrochemical cell.

  6. Evaluation program for secondary spacecraft cells

    NASA Technical Reports Server (NTRS)

    Harkness, J. D.

    1978-01-01

    The results of life cycle tests of secondary spacecraft cells are summarized. Cells consisted of seven sample classifications ranging from 3.0 to 20 ampere-hours, 1326 nlc nickel cadmium, 183 silver cadmium, and 125 silver zinc sealed cells. Variables examined include load, charge control, and temperature conditions.

  7. Miniaturized biological and electrochemical fuel cells: challenges and applications.

    PubMed

    Yang, Jie; Ghobadian, Sasan; Goodrich, Payton J; Montazami, Reza; Hashemi, Nastaran

    2013-09-14

    This paper discusses the fundamentals and developments of miniaturized fuel cells, both biological and electrochemical. An overview of microfluidic fuel cells, miniaturized microbial fuel cells, enzymatic biofuel cells, and implanted biofuel cells in an attempt to provide green energy and to power implanted microdevices is provided. Also, the challenges and applications of each type of fuel cell are discussed in detail. Most recent developments in fuel cell technologies such as novel catalysts, compact designs, and fabrication methods are reviewed. PMID:23503374

  8. Method for making an electrochemical cell

    DOEpatents

    Tuller, Harry L. (Wellesley, MA); Kramer, Steve A. (Somerville, MA); Spears, Marlene A. (Woburn, MA); Pal, Uday B. (Needham, MA)

    1996-01-01

    An electrochemical device including a solid electrolyte and solid electrode composed of materials having different chemical compositions and characterized by different electrical properties but having the same crystalline phase is provided. A method for fabricating an electrochemical device having a solid electrode and solid electrolyte characterized by the same crystalline phase is provided.

  9. Method for making an electrochemical cell

    DOEpatents

    Tuller, H.L.; Kramer, S.A.; Spears, M.A.; Pal, U.B.

    1996-04-23

    An electrochemical device is described including a solid electrolyte and solid electrode composed of materials having different chemical compositions and characterized by different electrical properties but having the same crystalline phase is provided. A method for fabricating an electrochemical device having a solid electrode and solid electrolyte characterized by the same crystalline phase is provided. 17 figs.

  10. Thermal conductor for high-energy electrochemical cells

    DOEpatents

    Hoffman, Joseph A. (Minneapolis, MN); Domroese, Michael K. (South St. Paul, MN); Lindeman, David D. (Hudson, WI); Radewald, Vern E. (Austin, TX); Rouillard, Roger (Beloeil, CA); Trice, Jennifer L. (Eagan, MN)

    2000-01-01

    A thermal conductor for use with an electrochemical energy storage device is disclosed. The thermal conductor is attached to one or both of the anode and cathode contacts of an electrochemical cell. A resilient portion of the conductor varies in height or position to maintain contact between the conductor and an adjacent wall structure of a containment vessel in response to relative movement between the conductor and the wall structure. The thermal conductor conducts current into and out of the electrochemical cell and conducts thermal energy between the electrochemical cell and thermally conductive and electrically resistive material disposed between the conductor and the wall structure. The thermal conductor may be fabricated to include a resilient portion having one of a substantially C-shaped, double C-shaped, Z-shaped, V-shaped, O-shaped, S-shaped, or finger-shaped cross-section. An elastomeric spring element may be configured so as to be captured by the resilient conductor for purposes of enhancing the functionality of the thermal conductor. The spring element may include a protrusion that provides electrical insulation between the spring conductor and a spring conductor of an adjacently disposed electrochemical cell in the presence of relative movement between the cells and the wall structure. The thermal conductor may also be fabricated from a sheet of electrically conductive material and affixed to the contacts of a number of electrochemical cells.

  11. Steel refining with an electrochemical cell

    DOEpatents

    Blander, M.; Cook, G.M.

    1985-05-21

    Disclosed is an apparatus for processing a metallic fluid containing iron oxide, container for a molten metal including an electrically conductive refractory disposed for contact with the molten metal which contains iron oxide, an electrolyte in the form of a basic slag on top of the molten metal, an electrode in the container in contact with the slag electrically separated from the refractory, and means for establishing a voltage across the refractory and the electrode to reduce iron oxide to iron at the surface of the refractory in contact with the iron oxide containing fluid. A process is disclosed for refining an iron product containing not more than about 10% by weight sulfur, comprising providing an electrolyte of a slag containing one or more of calcium oxide, magnesium oxide, silica or alumina, providing a cathode of the iron product in contact with the electrolyte, providing an anode in contact with the electrolyte electrically separated from the cathode, and operating an electrochemical cell formed by the anode, the cathode and the electrolyte to separate oxygen or sulfur present in the iron product therefrom.

  12. Steel refining with an electrochemical cell

    DOEpatents

    Blander, Milton (Palos Park, IL); Cook, Glenn M. (Naperville, IL)

    1988-01-01

    Apparatus for processing a metallic fluid containing iron oxide, container for a molten metal including an electrically conductive refractory disposed for contact with the molten metal which contains iron oxide, an electrolyte in the form of a basic slag on top of the molten metal, an electrode in the container in contact with the slag electrically separated from the refractory, and means for establishing a voltage across the refractory and the electrode to reduce iron oxide to iron at the surface of the refractory in contact with the iron oxide containing fluid. A process is disclosed for refining an iron product containing not more than about 10% by weight oxygen and not more than about 10% by weight sulfur, comprising providing an electrolyte of a slag containing one or more of calcium oxide, magnesium oxide, silica or alumina, providing a cathode of the iron product in contact with the electrolyte, providing an anode in contact with the electrolyte electrically separated from the cathode, and operating an electrochemical cell formed by the anode, the cathode and the electrolyte to separate oxygen or sulfur present in the iron product therefrom.

  13. Steel refining with an electrochemical cell

    DOEpatents

    Blander, M.; Cook, G.M.

    1988-05-17

    Apparatus is described for processing a metallic fluid containing iron oxide, container for a molten metal including an electrically conductive refractory disposed for contact with the molten metal which contains iron oxide, an electrolyte in the form of a basic slag on top of the molten metal, an electrode in the container in contact with the slag electrically separated from the refractory, and means for establishing a voltage across the refractory and the electrode to reduce iron oxide to iron at the surface of the refractory in contact with the iron oxide containing fluid. A process is disclosed for refining an iron product containing not more than about 10% by weight oxygen and not more than about 10% by weight sulfur, comprising providing an electrolyte of a slag containing one or more of calcium oxide, magnesium oxide, silica or alumina, providing a cathode of the iron product in contact with the electrolyte, providing an anode in contact with the electrolyte electrically separated from the cathode, and operating an electrochemical cell formed by the anode, the cathode and the electrolyte to separate oxygen or sulfur present in the iron product therefrom. 2 figs.

  14. Method of doping interconnections for electrochemical cells

    DOEpatents

    Pal, Uday B. (Monroeville, PA); Singhal, Subhash C. (Murrysville, PA); Moon, David M. (Pittsburgh, PA); Folser, George R. (Lower Burrell, PA)

    1990-01-01

    A dense, electronically conductive interconnection layer 26 is bonded on a porous, tubular, electronically conductive air electrode structure 16, optionally supported by a ceramic support 22, by (A) forming a layer of oxide particles of at least one of the metals Ca, Sr, Co, Ba or Mg on a part 24 of a first surface of the air electrode 16, (B) heating the electrode structure, (C) applying a halide vapor containing at least lanthanum halide and chromium halide to the first surface and applying a source of oxygen to a second opposite surface of the air electrode so that they contact at said first surface, to cause a reaction of the oxygen and halide and cause a dense lanthanum-chromium oxide structure to grow, from the first electrode surface, between and around the oxide particles, where the metal oxide particles get incoporated into the lanthanum-chromium oxide structure as it grows thicker with time, and the metal ions in the oxide particles diffuse into the bulk of the lanthamum-chromium oxide structure, to provide a dense, top, interconnection layer 26 on top of the air electrode 16. A solid electrolyte layer 18 can be applied to the uncovered portion of the air electrode, and a fuel electrode 20 can be applied to the solid electrolyte, to provide an electrochemical cell 10.

  15. Cell structure for electrochemical devices and method of making same

    DOEpatents

    Kaun, Thomas D. (320 Willow St., New Lenox, IL 60451)

    1993-01-01

    An electrochemical device comprises a plurality of cells, each cell including a laminate cell membrane, made up of a separator/electrolyte means interposed between alternating positive and negative electrodes, each type of electrode being respectively in common contact to a single current collector.

  16. Wick-and-pool electrodes for electrochemical cell

    DOEpatents

    Roche, Michael F. (Downers Grove, IL); Faist, Suzan M. (Haddonfield, NJ); Eberhart, James G. (Naperville, IL); Ross, Laurids E. (Naperville, IL)

    1980-01-01

    An electrode system includes a reservoir of liquid-metal reactant, and a wick extending from a submersed location within the reservoir into the molten electrolyte of an electrochemical cell structure. The wick is flooded with the liquid metal and thereby serves as one electrode within the cell. This electrode system has application in high-temperature batteries employing molten alkali metals or their alloys as active material within an electrode submersed within a molten salt electrolyte. It also can be used in electrochemical cells where the purification, separation or electrowinning of liquid metals is accomplished.

  17. Electrochemical cell for in-situ x-ray characterization

    SciTech Connect

    Doughty, D.H.; Ingersoll, D.; Rodriguez, M.A.

    1998-08-04

    An electrochemical cell suitable for in-situ XRD analysis is presented. Qualitative information such as phase formation and phase stability can be easily monitored using the in-situ cell design. Quantitative information such as lattice parameters and kinetic behavior is also straightforward. Analysis of the LiMn&sub2;O&sub4; spinel using this cell design shows that the lattice undergoes two major structural shrinkages at approx. 4.0 V and approx. 4.07 V during charging. These shrinkages correlate well with the two electrochemical waves observed and indicate the likelihood of two separate redox processes which charging and discharging.

  18. Electrochemical cell utilizing molten alkali metal electrode-reactant

    DOEpatents

    Virkar, Anil V. (Sandy, UT); Miller, Gerald R. (Salt Lake City, UT)

    1983-11-04

    An improved electrochemical cell comprising an additive-modified molten alkali metal electrode-reactant and/or electrolyte is disclosed. Various electrochemical cells employing a molten alkali metal, e.g., sodium, electrode in contact with a cationically conductive ceramic membrane experience a lower resistance and a lower temperature coefficient of resistance whenever small amounts of selenium are present at the interface of the electrolyte and the molten alkali metal. Further, cells having small amounts of selenium present at the electrolyte-molten metal interface exhibit less degradation of the electrolyte under long term cycling conditions.

  19. The Variation of Electrochemical Cell Potentials with Temperature

    ERIC Educational Resources Information Center

    Peckham, Gavin D.; McNaught, Ian J.

    2011-01-01

    Electrochemical cell potentials have no simple relationship with temperature but depend on the interplay between the sign and magnitude of the isothermal temperature coefficient, dE[degrees]/dT, and on the magnitude of the reaction quotient, Q. The variations in possible responses of standard and non-standard cell potentials to changes in the…

  20. Systems, methods and computer-readable media for modeling cell performance fade of rechargeable electrochemical devices

    DOEpatents

    Gering, Kevin L

    2013-08-27

    A system includes an electrochemical cell, monitoring hardware, and a computing system. The monitoring hardware periodically samples performance characteristics of the electrochemical cell. The computing system determines cell information from the performance characteristics of the electrochemical cell. The computing system also develops a mechanistic level model of the electrochemical cell to determine performance fade characteristics of the electrochemical cell and analyzing the mechanistic level model to estimate performance fade characteristics over aging of a similar electrochemical cell. The mechanistic level model uses first constant-current pulses applied to the electrochemical cell at a first aging period and at three or more current values bracketing a first exchange current density. The mechanistic level model also is based on second constant-current pulses applied to the electrochemical cell at a second aging period and at three or more current values bracketing the second exchange current density.

  1. Reconstitution of a Secondary Cell Wall in a Secondary Cell Wall-Deficient Arabidopsis Mutant

    PubMed Central

    Sakamoto, Shingo; Mitsuda, Nobutaka

    2015-01-01

    The secondary cell wall constitutes a rigid frame of cells in plant tissues where rigidity is required. Deposition of the secondary cell wall in fiber cells contributes to the production of wood in woody plants. The secondary cell wall is assembled through co-operative activities of many enzymes, and their gene expression is precisely regulated by a pyramidal cascade of transcription factors. Deposition of a transmuted secondary cell wall in empty fiber cells by expressing selected gene(s) in this cascade has not been attempted previously. In this proof-of-concept study, we expressed chimeric activators of 24 transcription factors that are preferentially expressed in the stem, in empty fiber cells of the Arabidopsis nst1-1 nst3-1 double mutant, which lacks a secondary cell wall in fiber cells, under the control of the NST3 promoter. The chimeric activators of MYB46, SND2 and ANAC075, as well as NST3, reconstituted a secondary cell wall with different characteristics from those of the wild type in terms of its composition. The transgenic lines expressing the SND2 or ANAC075 chimeric activator showed increased glucose and xylose, and lower lignin content, whereas the transgenic line expressing the MYB46 chimeric activator showed increased mannose content. The expression profile of downstream genes in each transgenic line was also different from that of the wild type. This study proposed a new screening strategy to identify factors of secondary wall formation and also suggested the potential of the artificially reconstituted secondary cell walls as a novel raw material for production of bioethanol and other chemicals. PMID:25535195

  2. Assessing corrosion problems in photovoltaic cells via electrochemical stress testing

    NASA Technical Reports Server (NTRS)

    Shalaby, H.

    1985-01-01

    A series of accelerated electrochemical experiments to study the degradation properties of polyvinylbutyral-encapsulated silicon solar cells has been carried out. The cells' electrical performance with silk screen-silver and nickel-solder contacts was evaluated. The degradation mechanism was shown to be electrochemical corrosion of the cell contacts; metallization elements migrate into the encapsulating material, which acts as an ionic conducting medium. The corrosion products form a conductive path which results in a gradual loss of the insulation characteristics of the encapsulant. The precipitation of corrosion products in the encapsulant also contributes to its discoloration which in turn leads to a reduction in its transparency and the consequent optical loss. Delamination of the encapsulating layers could be attributed to electrochemical gas evolution reactions. The usefulness of the testing technique in qualitatively establishing a reliability difference between metallizations and antireflection coating types is demonstrated.

  3. Continuous-feed electrochemical cell with nonpacking particulate electrode

    DOEpatents

    Cooper, J.F.

    1995-07-18

    An electrochemical cell providing full consumption of electrochemically active particles in a nonpacking, electrolyte-permeable bed has a tapered cell cavity bounded by two nonparallel surfaces separated by a distance that promotes bridging of particles across the cavity. The gap/particle size ratio is maintained as the particles are consumed, decrease in size, and travel from the point of entry to the narrower end of the cell. A cell of this configuration supports a bed of low packing density maintained in a dynamic steady state by alternate formation and collapse of particle bridges across the gap and associated voids over the entire active area of the cell. The cell design can be applied to refuelable zinc/air cells and zinc/ferrocyanide storage batteries. 6 figs.

  4. Continuous-feed electrochemical cell with nonpacking particulate electrode

    DOEpatents

    Cooper, John F. (Oakland, CA)

    1995-01-01

    An electrochemical cell providing full consumption of electrochemically active particles in a nonpacking, electrolyte-permeable bed has a tapered cell cavity bounded by two nonparallel surfaces separated by a distance that promotes bridging of particles across the cavity. The gap/particle size ratio is maintained as the particles are consumed, decrease in size, and travel from the point of entry to the narrower end of the cell. A cell of this configuration supports a bed of low packing density maintained in a dynamic steady state by alternate formation and collapse of particle bridges across the gap and associated voids over the entire active area of the cell. The cell design can be applied to refuelable zinc/air cells and zinc/ferrocyanide storage batteries.

  5. Secondary cell walls: biosynthesis and manipulation.

    PubMed

    Kumar, Manoj; Campbell, Liam; Turner, Simon

    2016-01-01

    Secondary cell walls (SCWs) are produced by specialized plant cell types, and are particularly important in those cells providing mechanical support or involved in water transport. As the main constituent of plant biomass, secondary cell walls are central to attempts to generate second-generation biofuels. Partly as a consequence of this renewed economic importance, excellent progress has been made in understanding how cell wall components are synthesized. SCWs are largely composed of three main polymers: cellulose, hemicellulose, and lignin. In this review, we will attempt to highlight the most recent progress in understanding the biosynthetic pathways for secondary cell wall components, how these pathways are regulated, and how this knowledge may be exploited to improve cell wall properties that facilitate breakdown without compromising plant growth and productivity. While knowledge of individual components in the pathway has improved dramatically, how they function together to make the final polymers and how these individual polymers are incorporated into the wall remain less well understood. PMID:26663392

  6. UHV, Electrochemical NMR, and Electrochemical Studies of Platinum/Ruthenium Fuel Cell C. Lu, C. Rice, and R. I. Masel*

    E-print Network

    Lu, Chang

    UHV, Electrochemical NMR, and Electrochemical Studies of Platinum/Ruthenium Fuel Cell Catalysts C It is well-known that platinum/ruthenium fuel cell catalysts show enhanced CO tolerance compared to pure to probe the origin of the ruthenium enhancement in Pt electrodes modified through Ru deposition

  7. Method of enhancing the wettability of boron nitride for use as an electrochemical cell separator

    DOEpatents

    McCoy, Lowell R. (Woodland Hills, CA)

    1982-01-01

    A felt or other fabric of boron nitride suitable for use as an interelecte separator within an electrochemical cell is wetted with a solution containing a thermally decomposable organic salt of an alkaline earth metal. An aqueous solution of magnesium acetate is the preferred solution for this purpose. After wetting the boron nitride, the solution is dried by heating at a sufficiently low temperature to prevent rapid boiling and the creation of voids within the separator. The dried material is then calcined at an elevated temperature in excess of 400.degree. C. to provide a coating of an oxide of magnesium on the surface of the boron nitride fibers. A fabric or felt of boron nitride treated in this manner is easily wetted by molten electrolytic salts, such as the alkali metal halides or alkaline earth metal halides, that are used in high temperature, secondary electrochemical cells.

  8. Method of enhancing the wettability of boron nitride for use as an electrochemical cell separator

    DOEpatents

    McCoy, L.R.

    1981-01-23

    A felt or other fabric of boron nitride suitable for use as an interelectrode separator within an electrochemical cell is wetted with a solution containing a thermally decomposable organic salt of an alkaline earth metal. An aqueous solution of magnesium acetate is the preferred solution for this purpose. After wetting the boron nitride, the solution is dried by heating at a sufficiently low temperature to prevent rapid boiling and the creation of voids within the separator. The dried material is then calcined at an elevated temperature in excess of 400/sup 0/C to provide a coating of an oxide of magnesium on the surface of the boron nitride fibers. A fabric or felt of boron nitride treated in this manner is easily wetted by molten electrolytic salts, such as the alkali metal halides or alkaline earth metal halides, that are used in high temperature, secondary electrochemical cells.

  9. Method of making an electrochemical sensing cell

    SciTech Connect

    Koning, G.; Bergveld, P.

    1985-08-13

    An in vivo electrochemical monitoring device is formed by a catheter-like member which terminates in a closed end having a wall with a fixed opening to admit fluid to be tested, such as blood in an artery. An electrochemical sensor, such as an ISFET device for monitoring the concentration of a particular ion in blood, is mounted inside the tube at a fixed location below the opening preferably a larger sensing chamber. An infusion channel in the tube is arranged to flood the sensor with a fluid of known chemical properties so that the sensor output can be calibrated. Under pressure the calibration fluid expels the test fluid out of the tube or chamber via the fixed opening. A method of constructing a suitable chamber on an ISFET wafer is also disclosed.

  10. Oxide modified air electrode surface for high temperature electrochemical cells

    DOEpatents

    Singh, Prabhakar (Export, PA); Ruka, Roswell J. (Churchill Boro, Allegheny County, PA)

    1992-01-01

    An electrochemical cell is made having a porous cermet electrode (16) and a porous lanthanum manganite electrode (14), with solid oxide electrolyte (15) between them, where the lanthanum manganite surface next to the electrolyte contains a thin discontinuous layer of high surface area cerium oxide and/or praseodymium oxide, preferably as discrete particles (30) in contact with the air electrode and electrolyte.

  11. Electrode electrolyte interlayers containing cerium oxide for electrochemical fuel cells

    DOEpatents

    Borglum, Brian P. (Edgewood, PA); Bessette, Norman F. (N. Huntingdon, PA)

    2000-01-01

    An electrochemical cell is made having a porous fuel electrode (16) and a porous air electrode (13), with solid oxide electrolyte (15) therebetween, where the air electrode surface opposing the electrolyte has a separate, attached, dense, continuous layer (14) of a material containing cerium oxide, and where electrolyte (16) contacts the continuous oxide layer (14), without contacting the air electrode (13).

  12. Mass spectrometric methods for monitoring redox processes in electrochemical cells

    PubMed Central

    Oberacher, Herbert; Pitterl, Florian; Erb, Robert; Plattner, Sabine

    2015-01-01

    Electrochemistry (EC) is a mature scientific discipline aimed to study the movement of electrons in an oxidation–reduction reaction. EC covers techniques that use a measurement of potential, charge, or current to determine the concentration or the chemical reactivity of analytes. The electrical signal is directly converted into chemical information. For in-depth characterization of complex electrochemical reactions involving the formation of diverse intermediates, products and byproducts, EC is usually combined with other analytical techniques, and particularly the hyphenation of EC with mass spectrometry (MS) has found broad applicability. The analysis of gases and volatile intermediates and products formed at electrode surfaces is enabled by differential electrochemical mass spectrometry (DEMS). In DEMS an electrochemical cell is sampled with a membrane interface for electron ionization (EI)-MS. The chemical space amenable to EC/MS (i.e., bioorganic molecules including proteins, peptides, nucleic acids, and drugs) was significantly increased by employing electrospray ionization (ESI)-MS. In the simplest setup, the EC of the ESI process is used to analytical advantage. A limitation of this approach is, however, its inability to precisely control the electrochemical potential at the emitter electrode. Thus, particularly for studying mechanistic aspects of electrochemical processes, the hyphenation of discrete electrochemical cells with ESI-MS was found to be more appropriate. The analytical power of EC/ESI-MS can further be increased by integrating liquid chromatography (LC) as an additional dimension of separation. Chromatographic separation was found to be particularly useful to reduce the complexity of the sample submitted either to the EC cell or to ESI-MS. Thus, both EC/LC/ESI-MS and LC/EC/ESI-MS are common. PMID:24338642

  13. Corner heating in rectangular solid oxide electrochemical cell generators

    DOEpatents

    Reichner, Philip (Plum Boro, PA)

    1989-01-01

    Disclosed is an improvement in a solid oxide electrochemical cell generator 1 having a rectangular design with four sides that meet at corners, and containing multiplicity of electrically connected fuel cells 11, where a fuel gas is passed over one side of said cells and an oxygen containing gas is passed into said cells, and said fuel is burned to form heat, electricity, and an exhaust gas. The improvement comprises passing the exhaust gases over the multiplicity of cells 11 in such a way that more of the heat in said exhaust gases flows at the corners of the generator, such as through channels 19.

  14. Development of ambient temperature secondary lithium cells

    NASA Technical Reports Server (NTRS)

    Subbarao, S.; Shen, D. H.; Dawson, S.; Deligiannis, F.; Taraszkiewicz, J.; Halpert, Gerald

    1987-01-01

    JPL is developing ambient temperature secondary lithium cells for future spacecraft applications. Prior studies on experimental laboratory type Li-TiS2 cells yielded promising results in terms of cycle life and rate capability. To further assess the performance of this cell, 5 Ah engineering model cells were developed. Initially baseline cells were designed and fabricated. Each cell had 15 cathodes and 16 anodes and the ratio of anode to cathode capacity is 6:1. A solution of 1.5 molar LiAsF6 in 2Me-THF was used as the electrolyte. Cells were evaluated for their cycle life at C/1 and C/5 discharge rates and 100 percent depth of discharge. The cells were cycled between voltage limits 1.7 and 2.8 volts. The rate of charge in all cases is C/10. The results obtained indicate that cells can operate at C/10 to C/2 discharge rates and have an initial energy density of 70 Wh/kg. Cells delivered more than 100 cycles at C/2 discharge rate. The details of cell design, the test program, and the results obtained are described.

  15. Electrochemical Characterization of Carbon Nanotubes for Fuel Cell MEA's

    NASA Technical Reports Server (NTRS)

    Panagaris, Jael; Loyselle, Patricia

    2004-01-01

    Single-walled and multi-walled carbon nanotubes from different sources have been evaluated before and after sonication to identify structural differences and evaluate electrochemical performance. Raman spectral analysis and cyclic voltammetry in situ with QCM were the principle means of evaluating the tubes. The raman data indicates that sonication in toluene modifies the structural properties of the nanotubes. Sonication also affects the electrochemical performance of single-walled nanotubes and the multi-walled tubes differently. The characterization of different types of carbon nanotubes leads up to identifying a potential candidate for incorporating carbon nanotubes for fuel cell MEA structures.

  16. Facile and quantitative electrochemical detection of yeast cell apoptosis

    NASA Astrophysics Data System (ADS)

    Yue, Qiulin; Xiong, Shiquan; Cai, Dongqing; Wu, Zhengyan; Zhang, Xin

    2014-03-01

    An electrochemical method based on square wave anodic stripping voltammetry (SWASV) was developed to detect the apoptosis of yeast cells conveniently and quantitatively through the high affinity between Cu2+ and phosphatidylserine (PS) translocated from the inner to the outer plasma membrane of the apoptotic cells. The combination of negatively charged PS and Cu2+ could decrease the electrochemical response of Cu2+ on the electrode. The results showed that the apoptotic rates of cells could be detected quantitatively through the variations of peak currents of Cu2+ by SWASV, and agreed well with those obtained through traditional flow cytometry detection. This work thus may provide a novel, simple, immediate and accurate detection method for cell apoptosis.

  17. Evaluation program for secondary spacecraft cells

    NASA Technical Reports Server (NTRS)

    Christy, D. E.; Harkness, J. D.

    1973-01-01

    A life cycle test of secondary electric batteries for spacecraft applications was conducted. A sample number of nickel cadmium batteries were subjected to general performance tests to determine the limit of their actual capabilities. Weaknesses discovered in cell design are reported and aid in research and development efforts toward improving the reliability of spacecraft batteries. A statistical analysis of the life cycle prediction and cause of failure versus test conditions is provided.

  18. Method for making an electrochemical cell

    DOEpatents

    Bates, John B. (Oak Ridge, TN); Dudney, Nancy J. (Knoxville, TN)

    1996-01-01

    Described is a thin-film battery, especially a thin-film microbattery, and a method for making same having application as a backup or primary integrated power source for electronic devices. The battery includes a novel electrolyte which is electrochemically stable and does not react with the lithium anode and a novel vanadium oxide cathode Configured as a microbattery, the battery can be fabricated directly onto a semiconductor chip, onto the semiconductor die or onto any portion of the chip carrier. The battery can be fabricated to any specified size or shape to meet the requirements of a particular application. The battery is fabricated of solid state materials and is capable of operation between -15.degree. C. and 150.degree. C.

  19. Method for making an electrochemical cell

    DOEpatents

    Bates, J.B.; Dudney, N.J.

    1996-10-22

    Described is a thin-film battery, especially a thin-film microbattery, and a method for making the same, having application as a backup or primary integrated power source for electronic devices. The battery includes a novel electrolyte which is electrochemically stable and does not react with the lithium anode and a novel vanadium oxide cathode. Configured as a microbattery, the battery can be fabricated directly onto a semiconductor chip, onto the semiconductor die or onto any portion of the chip carrier. The battery can be fabricated to any specified size or shape to meet the requirements of a particular application. The battery is fabricated of solid state materials and is capable of operation between {minus}15 C and 150 C. 9 figs.

  20. Selectable-Tip Corrosion-Testing Electrochemical Cell

    NASA Technical Reports Server (NTRS)

    Lomness, Janice; Hintze, Paul

    2008-01-01

    The figure depicts aspects of an electrochemical cell for pitting- corrosion tests of material specimens. The cell is designed to generate a region of corrosion having a pit diameter determined by the diameter of a selectable tip. The average depth of corrosion is controlled by controlling the total electric charge passing through the cell in a test. The cell is also designed to produce minimal artifacts associated with crevice corrosion. There are three selectable tips, having diameters of 0.1 in. (0.254 cm), 0.3 in. (0.762 cm), and 0.6 in. (1.524 cm), respectively.

  1. Photoelectrolysis of water in semiconductor septum electrochemical photovoltaic cells

    SciTech Connect

    Tien, H.T.; Chen, J.W. )

    1992-01-01

    Producing hydrogen from water has been the dream of generations of energy-conscious scientists and engineers. That dream may at last be realized in the semiconductor septum electrochemical photovoltaic (SC-SEP) cell, which is modeled after nature's photosynthetic thylakoid membrane. The novel SC-SEP cell arose from studies of pigmented bilayer lipid membranes. The cell is easy to construct and simple to operate. It appears to offer a practical approach to the photochemical conversion and storage of solar energy. This report describes how hydrogen is produced from artificial sea water when an SC-SEP cell is irradiated by the visible light of the solar spectrum.

  2. Engineering secondary cell wall deposition in plants

    PubMed Central

    Yang, Fan; Mitra, Prajakta; Zhang, Ling; Prak, Lina; Verhertbruggen, Yves; Kim, Jin-Sun; Sun, Lan; Zheng, Kejian; Tang, Kexuan; Auer, Manfred; Scheller, Henrik V; Loqué, Dominique

    2013-01-01

    Lignocellulosic biomass was used for thousands of years as animal feed and is now considered a great sugar source for biofuels production. It is composed mostly of secondary cell walls built with polysaccharide polymers that are embedded in lignin to reinforce the cell wall structure and maintain its integrity. Lignin is the primary material responsible for biomass recalcitrance to enzymatic hydrolysis. During plant development, deep reductions of lignin cause growth defects and often correlate with the loss of vessel integrity that adversely affects water and nutrient transport in plants. The work presented here describes a new approach to decrease lignin content while preventing vessel collapse and introduces a new strategy to boost transcription factor expression in native tissues. We used synthetic biology tools in Arabidopsis to rewire the secondary cell network by changing promoter-coding sequence associations. The result was a reduction in lignin and an increase in polysaccharide depositions in fibre cells. The promoter of a key lignin gene, C4H, was replaced by the vessel-specific promoter of transcription factor VND6. This rewired lignin biosynthesis specifically for vessel formation while disconnecting C4H expression from the fibre regulatory network. Secondly, the promoter of the IRX8 gene, secondary cell wall glycosyltransferase, was used to express a new copy of the fibre transcription factor NST1, and as the IRX8 promoter is induced by NST1, this also created an artificial positive feedback loop (APFL). The combination of strategies—lignin rewiring with APFL insertion—enhances polysaccharide deposition in stems without over-lignifying them, resulting in higher sugar yields after enzymatic hydrolysis. PMID:23140549

  3. Systems, methods and computer readable media for estimating capacity loss in rechargeable electrochemical cells

    DOEpatents

    Gering, Kevin L.

    2013-06-18

    A system includes an electrochemical cell, monitoring hardware, and a computing system. The monitoring hardware periodically samples charge characteristics of the electrochemical cell. The computing system periodically determines cell information from the charge characteristics of the electrochemical cell. The computing system also periodically adds a first degradation characteristic from the cell information to a first sigmoid expression, periodically adds a second degradation characteristic from the cell information to a second sigmoid expression and combines the first sigmoid expression and the second sigmoid expression to develop or augment a multiple sigmoid model (MSM) of the electrochemical cell. The MSM may be used to estimate a capacity loss of the electrochemical cell at a desired point in time and analyze other characteristics of the electrochemical cell. The first and second degradation characteristics may be loss of active host sites and loss of free lithium for Li-ion cells.

  4. Electrochemical properties of electrospun poly(5-cyanoindole) submicron-fibrous electrode for zinc/polymer secondary battery

    NASA Astrophysics Data System (ADS)

    Cai, Zhijiang; Guo, Jie; Yang, Haizheng; Xu, Yi

    2015-04-01

    This study aims to develop an aqueous zinc/electrospun poly(5-cyanoindole) fibers secondary battery system. Zn foil and ZnCl2 are used as anode active materials and the electrolytic solution, respectively. Poly(5-cyanoindole) synthesized by chemical oxidation is electrospun into fibers and used as cathode active materials. FTIR and NMR test are carried out to investigate the chemical structure of poly(5-cyanoindole). Surface properties of electrospun poly(5-cyanoindole) fibers are studied by SEM, TEM, and BET. The performance of zinc/electrospun poly(5-cyanoindole) fibers battery system is evaluated in term of electrical conductivity, cyclic voltammogram, electrochemical impedance spectroscopy, discharge capacity and durability test. The cell achieves 2.0 V electromotive force with about 107-61 Ah Kg-1 discharge capacity at 0.2C-10C rate. At 800th cycle, the discharge capacity remains 80-57 Ah Kg-1 at 0.2C-2C rate, which is about 75-63% of the maximum discharge capacity. These results indicate that the cell has very excellent cyclic properties as well as fast charge/discharge properties. Electrospun poly(5-cyanoindole) fibers have been proved to be a better candidate than polyindole powder as cathode material in zinc/polymer battery.

  5. Separation of CO2 from flue gas using electrochemical cells

    SciTech Connect

    Pennline, H.W; Granite, E.J.; Luebke, D.R; Kitchin, J.R; Landon, J.; Weiland, L.M.

    2010-06-01

    ABSTRACT Past research with high temperature molten carbonate electrochemical cells has shown that carbon dioxide can be separated from flue gas streams produced by pulverized coal combustion for power generation, However, the presence of trace contaminants, i.e" sulfur dioxide and nitric oxides, will impact the electrolyte within the cell. If a lower temperature cell could be devised that would utilize the benefits of commercially-available, upstream desulfurization and denitrification in the power plant, then this CO2 separation technique can approach more viability in the carbon sequestration area, Recent work has led to the assembly and successful operation of a low temperature electrochemical cell. In the proof-of-concept testing with this cell, an anion exchange membrane was sandwiched between gas-diffusion electrodes consisting of nickel-based anode electrocatalysts on carbon paper. When a potential was applied across the cell and a mixture of oxygen and carbon dioxide was flowed over the wetted electrolyte on the cathode side, a stream of CO2 to O2 was produced on the anode side, suggesting that carbonate/ bicarbonate ions are the CO2 carrier in the membrane. Since a mixture of CO 2 and 02 is produced, the possibility exists to use this stream in oxy-firing of additional fuel. From this research, a novel concept for efficiently producing a carbon dioxide rich effiuent from combustion of a fossil fuel was proposed. Carbon dioxide and oxygen are captured from the flue gas of a fossilfuel combustor by one or more electrochemical cells or cell stacks. The separated stream is then transferred to an oxy-fired combustor which uses the gas stream for ancillary combustion, ultimately resulting in an effluent rich in carbon dioxide, A portion of the resulting flow produced by the oxy-fired combustor may be continuously recycled back into the oxy-fired combustor for temperature control and an optimal carbon dioxide rich effluent.

  6. Separation of CO2 from flue gas using electrochemical cells

    SciTech Connect

    Pennline HW, Granite EJ, Luebke DR,

    2010-06-01

    Past research with high temperature molten carbonate electrochemical cells has shown that carbon dioxide can be separated from flue gas streams produced by pulverized coal combustion for power generation. However, the presence of trace contaminants, i.e., sulfur dioxide and nitric oxides, will impact the electrolyte within the cell. If a lower temperature cell could be devised that would utilize the benefits of commercially-available, upstream desulfurization and denitrification in the power plant, then this CO2 separation technique can approach more viability in the carbon sequestration area. Recent work has led to the assembly and successful operation of a low temperature electrochemical cell. In the proof-of-concept testing with this cell, an anion exchange membrane was sandwiched between gas-diffusion electrodes consisting of nickel-based anode electrocatalysts on carbon paper. When a potential was applied across the cell and a mixture of oxygen and carbon dioxide was flowed over the wetted electrolyte on the cathode side, a stream of CO2 to O2 was produced on the anode side, suggesting that carbonate/ bicarbonate ions are the CO2 carrier in the membrane. Since a mixture of CO2 and O2 is produced, the possibility exists to use this stream in oxy-firing of additional fuel. From this research, a novel concept for efficiently producing a carbon dioxide rich effluent from combustion of a fossil fuel was proposed. Carbon dioxide and oxygen are captured from the flue gas of a fossilfuel combustor by one or more electrochemical cells or cell stacks. The separated stream is then transferred to an oxy-fired combustor which uses the gas stream for ancillary combustion, ultimately resulting in an effluent rich in carbon dioxide. A portion of the resulting flow produced by the oxy-fired combustor may be continuously recycled back into the oxy-fired combustor for temperature control and an optimal carbon dioxide rich effluent

  7. Review of electrochemical impregnation for nickel cadmium cells. [aerospace applications

    NASA Technical Reports Server (NTRS)

    Gross, S.

    1977-01-01

    A method of loading active material within the electrodes of nickel cadmium cells is examined. The basic process of electrochemical impregnation of these electrodes is detailed, citing the principle that when current is applied reactions occur which remove hydrogen ions from solution, making the interior of the plaque less acidic. Electrodes result which are superior in energy density, stability, and life. The technology is reviewed and illustrated with typical performance data. Recommendations are made for additional research and development.

  8. Method of making gas diffusion layers for electrochemical cells

    DOEpatents

    Frisk, Joseph William (Oakdale, MN); Boand, Wayne Meredith (Lino Lakes, MN); Larson, James Michael (Saint Paul, MN)

    2002-01-01

    A method is provided for making a gas diffusion layer for an electrochemical cell comprising the steps of: a) combining carbon particles and one or more surfactants in a typically aqueous vehicle to make a preliminary composition, typically by high shear mixing; b) adding one or more highly fluorinated polymers to said preliminary composition by low shear mixing to make a coating composition; and c) applying the coating composition to an electrically conductive porous substrate, typically by a low shear coating method.

  9. Protective interlayer for high temperature solid electrolyte electrochemical cells

    DOEpatents

    Isenberg, Arnold O. (Forest Hills Boro, PA); Ruka, Roswell J. (Churchill Boro, PA); Zymboly, Gregory E. (Penn Hills Township, Allegheny County, PA)

    1985-01-01

    A high temperature, solid electrolyte electrochemical cell is made, having a first and second electrode with solid electrolyte between them, where the electrolyte is formed by hot chemical vapor deposition, where a solid, interlayer material, which is electrically conductive, oxygen permeable, and protective of electrode material from hot metal halide vapor attack, is placed between the first electrode and the electrolyte, to protect the first electrode from the hot metal halide vapors during vapor deposition.

  10. Protective interlayer for high temperature solid electrolyte electrochemical cells

    DOEpatents

    Isenberg, Arnold O. (Forest Hills Boro, PA); Ruka, Roswell J. (Churchill Boro, PA)

    1986-01-01

    A high temperature, solid electrolyte electrochemical cell is made, having a first and second electrode with solid electrolyte between them, where the electrolyte is formed by hot chemical vapor deposition, where a solid, interlayer material, which is electrically conductive, oxygen permeable, and protective of electrode material from hot metal halide vapor attack, is placed between the first electrode and the electrolyte, to protect the first electrode from the hot metal halide vapors during vapor deposition.

  11. Protective interlayer for high temperature solid electrolyte electrochemical cells

    DOEpatents

    Isenberg, Arnold O. (Forest Hills Boro, PA); Ruka, Roswell J. (Churchill Boro, PA)

    1987-01-01

    A high temperature, solid electrolyte electrochemical cell is made, having a first and second electrode with solid electrolyte between them, where the electrolyte is formed by hot chemical vapor deposition, where a solid, interlayer material, which is electrically conductive, oxygen permeable, and protective of electrode material from hot metal halide vapor attack, is placed between the first electrode and the electrolyte, to protect the first electrode from the hot metal halide vapors during vapor deposition.

  12. Polymer-electrolyte membrane, electrochemical fuel cell, and related method

    DOEpatents

    Krishnan, Lakshmi; Yeager, Gary William; Soloveichik, Grigorii Lev

    2014-12-09

    A polymer-electrolyte membrane is presented. The polymer-electrolyte membrane comprises an acid-functional polymer, and an additive incorporated in at least a portion of the membrane. The additive comprises a fluorinated cycloaliphatic additive, a hydrophobic cycloaliphatic additive, or combinations thereof, wherein the additive has a boiling point greater than about 120.degree. C. An electrochemical fuel cell including the polymer-electrolyte membrane, and a related method, are also presented.

  13. Protective interlayer for high temperature solid electrolyte electrochemical cells

    DOEpatents

    Singh, Prabhakar (Export, PA); Vasilow, Theodore R. (Manor, PA); Richards, Von L. (Angola, IN)

    1996-01-01

    The invention comprises of an electrically conducting doped or admixed cerium oxide composition with niobium oxide and/or tantalum oxide for electrochemical devices, characterized by the general formula: Nb.sub.x Ta.sub.y Ce.sub.1-x-y O.sub.2 where x is about 0.0 to 0.05, y is about 0.0 to 0.05, and x+y is about 0.02 to 0.05, and where x is preferably about 0.02 to 0.05 and y is 0, and a method of making the same. This novel composition is particularly applicable in forming a protective interlayer of a high temperature, solid electrolyte electrochemical cell (10), characterized by a first electrode (12); an electrically conductive interlayer (14) of niobium and/or tantalum doped cerium oxide deposited over at least a first portion (R) of the first electrode; an interconnect (16) deposited over the interlayer; a solid electrolyte (18) deposited over a second portion of the first electrode, the first portion being discontinuous from the second portion; and, a second electrode (20) deposited over the solid electrolyte. The interlayer (14) is characterized as being porous and selected from the group consisting of niobium doped cerium oxide, tantalum doped cerium oxide, and niobium and tantalum doped cerium oxide or admixtures of the same. The first electrode (12), an air electrode, is a porous layer of doped lanthanum manganite, the solid electrolyte layer (18) is a dense yttria stabilized zirconium oxide, the interconnect layer (16) is a dense, doped lanthanum chromite, and the second electrode (20), a fuel electrode, is a porous layer of nickel-zirconium oxide cermet. The electrochemical cell (10) can take on a plurality of shapes such as annular, planar, etc. and can be connected to a plurality of electrochemical cells in series and/or in parallel to generate electrical energy.

  14. Protective interlayer for high temperature solid electrolyte electrochemical cells

    DOEpatents

    Singh, P.; Vasilow, T.R.; Richards, V.L.

    1996-05-14

    The invention is comprised of an electrically conducting doped or admixed cerium oxide composition with niobium oxide and/or tantalum oxide for electrochemical devices, characterized by the general formula: Nb{sub x}Ta{sub y}Ce{sub 1{minus}x{minus}y}O{sub 2} where x is about 0.0 to 0.05, y is about 0.0 to 0.05, and x+y is about 0.02 to 0.05, and where x is preferably about 0.02 to 0.05 and y is 0, and a method of making the same is also described. This novel composition is particularly applicable in forming a protective interlayer of a high temperature, solid electrolyte electrochemical cell, characterized by a first electrode; an electrically conductive interlayer of niobium and/or tantalum doped cerium oxide deposited over at least a first portion of the first electrode; an interconnect deposited over the interlayer; a solid electrolyte deposited over a second portion of the first electrode, the first portion being discontinuous from the second portion; and, a second electrode deposited over the solid electrolyte. The interlayer is characterized as being porous and selected from the group consisting of niobium doped cerium oxide, tantalum doped cerium oxide, and niobium and tantalum doped cerium oxide or admixtures of the same. The first electrode, an air electrode, is a porous layer of doped lanthanum manganite, the solid electrolyte layer is a dense yttria stabilized zirconium oxide, the interconnect layer is a dense, doped lanthanum chromite, and the second electrode, a fuel electrode, is a porous layer of nickel-zirconium oxide cermet. The electrochemical cell can take on a plurality of shapes such as annular, planar, etc. and can be connected to a plurality of electrochemical cells in series and/or in parallel to generate electrical energy. 5 figs.

  15. Cycloaliphatic epoxide-based photocured gelled electrolytes for secondary lithium battery applications. Electrochemical kinetic studies

    NASA Astrophysics Data System (ADS)

    Nagasubramanian, G.; Surampudi, S.; Halpert, G.

    1994-06-01

    Cycloaliphatic epoxide-based thin gelled films prepared by ultraviolet photocuring were characterized electrochemically. Mixtures of ethylene carbonate and various organic liquids in different volume ratios were used as solvents. General composition of the electrolyte was cycloaliphatic epoxide (being sold under the trade name ENVIBAR by Union Carbide) 10 to 28 weight percent (w/o), polyethylene oxide (200,000 Mw) 4 to 10 w/o, LiAsF6, 6 to 22 w/o, and mixed solvents (of different volume ratios) 80 to 40 w/o. Thin gelled films were formed on lithium (Li) electrodes and subjected to electrochemical studies. Typical values of bulk electrolyte specific conductivity and interfacial resistance obtained from ac impedance and dc measurements at room temperatures are 2 x 10(exp -3) S cm(exp -1) and 3.2 Omega cm(exp 2), respectively. Charge/discharge characteristics of the cells of the Li/electrolyte/TiS2 type were evaluated. Cathode utilization was only 33% of the total capacity.

  16. Fuel Cells and Electrochemical Energy Storage.

    ERIC Educational Resources Information Center

    Sammells, Anthony F.

    1983-01-01

    Discusses the nature of phosphoric acid, molten carbonate, and solid oxide fuel cells and major features and types of batteries used for electrical energy storage. Includes two tables presenting comparison of major battery features and summary of major material problems in the sodium-sulfur and lithium-alloy metal sulfide batteries. (JN)

  17. Composite bipolar plate for electrochemical cells

    DOEpatents

    Wilson, Mahlon S. (Los Alamos, NM); Busick, Deanna N. (Los Alamos, NM)

    2001-01-01

    A bipolar separator plate for fuel cells consists of a molded mixture of a vinyl ester resin and graphite powder. The plate serves as a current collector and may contain fluid flow fields for the distribution of reactant gases. The material is inexpensive, electrically conductive, lightweight, strong, corrosion resistant, easily mass produced, and relatively impermeable to hydrogen gas. The addition of certain fiber reinforcements and other additives can improve the properties of the composite material without significantly increasing its overall cost.

  18. Electrochemical cell apparatus having an exterior fuel mixer nozzle

    DOEpatents

    Reichner, P.; Doshi, V.B.

    1992-12-08

    An electrochemical apparatus is made having a generator section containing electrochemical cells, a fresh gaseous feed fuel inlet, a gaseous feed oxidant inlet, and at least one hot gaseous spent fuel recirculation channel, where the spent fuel recirculation channel, a portion of which is in contact with the outside of a mixer chamber, passes from the generator chamber to combine with the fresh feed fuel inlet at the entrance to the mixer chamber, and a mixer nozzle is located at the entrance to the mixer chamber, where the mixer chamber connects with the reforming chamber, and where the mixer-diffuser chamber and mixer nozzle are exterior to and spaced apart from the combustion chamber, and the generator chamber, and the mixer nozzle can operate below 400 C. 2 figs.

  19. Electrochemical cell apparatus having an exterior fuel mixer nozzle

    DOEpatents

    Reichner, Philip (Plum Borough, PA); Doshi, Vinod B. (Monroeville, PA)

    1992-01-01

    An electrochemical apparatus (10) is made having a generator section (22) containing electrochemical cells (16), a fresh gaseous feed fuel inlet (28), a gaseous feed oxidant inlet (30), and at least one hot gaseous spent fuel recirculation channel (46), where the spent fuel recirculation channel (46), a portion of which is in contact with the outside of a mixer chamber (52), passes from the generator chamber (22) to combine with the fresh feed fuel inlet (28) at the entrance to the mixer chamber, and a mixer nozzle (50) is located at the entrance to the mixer chamber, where the mixer chamber (52) connects with the reforming chamber (54), and where the mixer-diffuser chamber (52) and mixer nozzle (50) are exterior to and spaced apart from the combustion chamber (24), and the generator chamber (22), and the mixer nozzle (50) can operate below 400.degree. C.

  20. An Electrochemical Cell for Selective Lithium Capture from Seawater.

    PubMed

    Kim, Joo-Seong; Lee, Yong-Hee; Choi, Seungyeon; Shin, Jaeho; Dinh, Hung-Cuong; Choi, Jang Wook

    2015-08-18

    Lithium (Li) is a core element of Li-ion batteries (LIBs). Recent developments in mobile electronics such as smartphones and tablet PCs as well as advent of large-scale LIB applications including electrical vehicles and grid-level energy storage systems have led to an increase in demand for LIBs, giving rise to a concern on the availability and market price of Li resources. However, the current Lime-Soda process that is responsible for greater than 80% of worldwide Li resource supply is applicable only in certain regions on earth where the Li concentrations are sufficiently high (salt lakes or salt pans). Moreover, not only is the process time-consuming (12-18 months), but post-treatments are also required for the purification of Li. Here, we have devised a location-independent electrochemical system for Li capture, which can operate within a short time period (a few hours to days). By engaging olivine LiFePO4 active electrode that improves interfacial properties via polydopamine coating, the electrochemical cell achieves 4330 times amplification in Li/Na ion selectivity (Li/Na molar ratio of initial solution = 0.01 and Li/Na molar ratio of final electrode = 43.3). In addition, the electrochemical system engages an I(-)/I3(-) redox couple in the other electrode for balancing of the redox states on both electrode sides and sustainable operations of the entire cell. Based on the electrochemical results, key material and interfacial properties that affect the selectivity in Li capture are identified. PMID:25920476

  1. Method of electrode fabrication for solid oxide electrochemical cells

    DOEpatents

    Jensen, Russell R. (Murrysville, PA)

    1990-01-01

    A process for fabricating cermet electrodes for solid oxide electrochemical cells by sintering is disclosed. First, a porous metal electrode is fabricated on a solid oxide cell, such as a fuel cell by, for example, sintering, and is then infiltrated with a high volume fraction stabilized zirconia suspension. A second sintering step is used to sinter the infiltrated zirconia to a high density in order to more securely attach the electrode to the solid oxide electrolyte of the cell. High performance fuel electrodes can be obtained with this process. Further electrode performance enhancement may be achieved if stabilized zirconia doped with cerium oxide, chromium oxide, titanium oxide, and/or praseodymium oxide for electronic conduction is used.

  2. Pore size engineering applied to starved electrochemical cells and batteries

    NASA Technical Reports Server (NTRS)

    Abbey, K. M.; Thaller, L. H.

    1982-01-01

    To maximize performance in starved, multiplate cells, the cell design should rely on techniques which widen the volume tolerance characteristics. These involve engineering capillary pressure differences between the components of an electrochemical cell and using these forces to promote redistribution of electrolyte to the desired optimum values. This can be implemented in practice by prescribing pore size distributions for porous back-up plates, reservoirs, and electrodes. In addition, electrolyte volume management can be controlled by incorporating different pore size distributions into the separator. In a nickel/hydrogen cell, the separator must contain pores similar in size to the small pores of both the nickel and hydrogen electrodes in order to maintain an optimum conductive path for the electrolyte. The pore size distributions of all components should overlap in such a way as to prevent drying of the separator and/or flooding of the hydrogen electrode.

  3. Method of electrode fabrication for solid oxide electrochemical cells

    DOEpatents

    Jensen, R.R.

    1990-11-20

    A process for fabricating cermet electrodes for solid oxide electrochemical cells by sintering is disclosed. First, a porous metal electrode is fabricated on a solid oxide cell, such as a fuel cell by, for example, sintering, and is then infiltrated with a high volume fraction stabilized zirconia suspension. A second sintering step is used to sinter the infiltrated zirconia to a high density in order to more securely attach the electrode to the solid oxide electrolyte of the cell. High performance fuel electrodes can be obtained with this process. Further electrode performance enhancement may be achieved if stabilized zirconia doped with cerium oxide, chromium oxide, titanium oxide, and/or praseodymium oxide for electronic conduction is used. 5 figs.

  4. Electrochemical characterisation of fuel cell stack during cold start

    NASA Astrophysics Data System (ADS)

    Harel, F.; Bégot, S.; Wasterlain, S.; Candusso, D.

    2011-05-01

    Fuel cell self start at negative temperature conditions is not an easy task due to the water produced by the reduction of oxygen at the cathode. This amount of water can turn into ice and block the reaction before the temperature inside the fuel cell reaches positive values. The mechanism of the physical process which leads to oxidant starvation phenomena when ice appears is not yet well identified. In order to obtain a deeper understanding of this problem, the article presents some experimental investigations conducted on a short fuel cell stack. These experiments simulate vehicle technology operated in cold start conditions not with the primary objective to reach a successful and rapid start-up but much rather to characterise and understand the cold start phenomena until starvation occurs. A number of polarisation curves, electrochemical spectroscopy and cyclic voltammetry measurements are done on the stack before, after and also during the cold starts experiments. It is observed that the process of drying and cooling down prior to cold start have a great impact on the electrochemical cathode area. The results obtained show the evolution of the stack behaviour during the low temperature operation with a slow production of frost. The consequence on the individual cells in terms of inhomogeneous degradation is highlighted.

  5. Electrochemical Cell for Obtaining Oxygen from Carbon Dioxide Atmospheres

    NASA Technical Reports Server (NTRS)

    Hooker, Matthew; Rast, H. Edward; Rogers, Darren K.; Borja, Luis; Clark, Kevin; Fleming, Kimberly; Mcgurren, Michael; Oldaker, Tom; Sweet, Nanette

    1989-01-01

    To support human life on the Martian surface, an electrochemical device will be required to obtain oxygen from the carbon dioxide rich atmosphere. The electrolyte employed in such a device must be constructed from extremely thin, dense membranes to efficiently acquire the oxygen necessary to support life. A forming process used industrially in the production of multilayer capacitors and electronic substrates was adapted to form the thin membranes required. The process, known as the tape casting, involves the suspension consisting of solvents and binders. The suspension is passed under a blade, resulting in the production of ceramic membranes between 0.1 and 0.5 mm thick. Once fired, the stabilized zirconia membranes were assembled into the cell design by employing a zirconium phosphate solution as the sealing agent. The resulting ceramic-to-ceramic seals were found to be structurally sound and gas-tight. Furthermore, by using a zirconia-based solution to assemble the cell, the problem of a thermal expansion mismatch was alleviated. By adopting an industrial forming process to produce thin membranes, an electrochemical cell for obtaining oxygen from carbon dioxide was produced. The proposed cell design is unique in that it does not require a complicated manifold system for separating the various gases present in this process, nor does it require a series of complex electrical connections. Thus, the device can reliably obtain the vital oxygen supply from the toxic carbon dioxide atmosphere.

  6. Battery paste compositions and electrochemical cells for use therewith

    DOEpatents

    Olson, John B. (Boulder, CO)

    1999-12-07

    An improved battery paste composition and a lead-acid electrochemical cell which incorporates the composition. The cell includes a positive current collector and a negative current collector which are each coated with a paste containing one or more lead-containing compositions and a paste vehicle to form a positive plate and a negative plate. An absorbent electrolyte-containing separator member may also be positioned between the positive and negative plates. The paste on the positive current collector, the negative current collector, or both further includes a special additive consisting of polyvinylsulfonic acid or salts thereof which provides many benefits including improved battery cycle life, increased charge capacity, and enhanced overall stability. The additive also makes the pastes smoother and more adhesive, thereby improving the paste application process. The paste compositions of interest may be used in conventional flat-plate cells or in spirally wound batteries with equal effectiveness.

  7. Battery paste compositions and electrochemical cells for use therewith

    DOEpatents

    Olson, John B. (Boulder, CO)

    1999-02-16

    An improved battery paste composition and a lead-acid electrochemical cell which incorporates the composition. The cell includes a positive current collector and a negative current collector which are each coated with a paste containing one or more lead-containing compositions and a paste vehicle to form a positive plate and a negative plate. An absorbent electrolyte-containing separator member may also be positioned between the positive and negative plates. The paste on the positive current collector, the negative current collector, or both further includes a special additive consisting of polyvinylsulfonic acid or salts thereof which provides many benefits including improved battery cycle life, increased charge capacity, and enhanced overall stability. The additive also makes the pastes smoother and more adhesive, thereby improving the paste application process. The paste compositions of interest may be used in conventional flat-plate cells or in spirally wound batteries with equal effectiveness.

  8. Cell structure for electrochemical devices and method of making same

    DOEpatents

    Kaun, Thomas D.

    2007-03-27

    An electrochemical device comprising alternating layers of positive and negative electrodes separated from each other by separator layers. The electrode layers extend beyond the periphery of the separator layers providing superior contact between the electrodes and battery terminals, eliminating the need for welding the electrode to the terminal. Electrical resistance within the battery is decreased and thermal conductivity of the cell is increased allowing for superior heat removal from the battery and increased efficiency. Increased internal pressure within the battery can be alleviated without damaging or removing the battery from service while keeping the contents of the battery sealed off from the atmosphere by a pressure release system. Nonoperative cells within a battery assembly can also be removed from service by shorting the nonoperative cell thus decreasing battery life.

  9. Battery paste compositions and electrochemical cells for use therewith

    DOEpatents

    Olson, J.B.

    1999-02-16

    An improved battery paste composition and a lead-acid electrochemical cell which incorporates the composition are disclosed. The cell includes a positive current collector and a negative current collector which are each coated with a paste containing one or more lead-containing compositions and a paste vehicle to form a positive plate and a negative plate. An absorbent electrolyte-containing separator member may also be positioned between the positive and negative plates. The paste on the positive current collector, the negative current collector, or both further includes a special additive consisting of polyvinyl sulfonic acid or salts thereof which provides many benefits including improved battery cycle life, increased charge capacity, and enhanced overall stability. The additive also makes the pastes smoother and more adhesive, thereby improving the paste application process. The paste compositions of interest may be used in conventional flat-plate cells or in spirally wound batteries with equal effectiveness. 2 figs.

  10. In Vitro Electrochemical Corrosion and Cell Viability Studies on Nickel-Free Stainless Steel Orthopedic Implants

    PubMed Central

    Salahinejad, Erfan; Hadianfard, Mohammad Jafar; Macdonald, Digby Donald; Sharifi-Asl, Samin; Mozafari, Masoud; Walker, Kenneth J.; Rad, Armin Tahmasbi; Madihally, Sundararajan V.; Tayebi, Lobat

    2013-01-01

    The corrosion and cell viability behaviors of nanostructured, nickel-free stainless steel implants were studied and compared with AISI 316L. The electrochemical studies were conducted by potentiodynamic polarization and electrochemical impedance spectroscopic measurements in a simulated body fluid. Cytocompatibility was also evaluated by the adhesion behavior of adult human stem cells on the surface of the samples. According to the results, the electrochemical behavior is affected by a compromise among the specimen's structural characteristics, comprising composition, density, and grain size. The cell viability is interpreted by considering the results of the electrochemical impedance spectroscopic experiments. PMID:23630603

  11. Microfabricated Electrochemical Cell-Based Biosensors for Analysis of Living Cells In Vitro

    PubMed Central

    Wang, Jun; Wu, Chengxiong; Hu, Ning; Zhou, Jie; Du, Liping; Wang, Ping

    2012-01-01

    Cellular biochemical parameters can be used to reveal the physiological and functional information of various cells. Due to demonstrated high accuracy and non-invasiveness, electrochemical detection methods have been used for cell-based investigation. When combined with improved biosensor design and advanced measurement systems, the on-line biochemical analysis of living cells in vitro has been applied for biological mechanism study, drug screening and even environmental monitoring. In recent decades, new types of miniaturized electrochemical biosensor are emerging with the development of microfabrication technology. This review aims to give an overview of the microfabricated electrochemical cell-based biosensors, such as microelectrode arrays (MEA), the electric cell-substrate impedance sensing (ECIS) technique, and the light addressable potentiometric sensor (LAPS). The details in their working principles, measurement systems, and applications in cell monitoring are covered. Driven by the need for high throughput and multi-parameter detection proposed by biomedicine, the development trends of electrochemical cell-based biosensors are also introduced, including newly developed integrated biosensors, and the application of nanotechnology and microfluidic technology. PMID:25585708

  12. ENCH 473 Electrochemical Energy Engineering ENCH 648K Advanced Batteries and Fuel Cells

    E-print Network

    Rubloff, Gary W.

    ENCH 473 Electrochemical Energy Engineering ENCH 648K Advanced Batteries and Fuel Cells Spring 2014 Syllabus Course: ENCH 473 Electrochemical Energy Engineering ENCH: 648K Advanced Batteries and Fuel Cells vehicles and renewable energy storage. One critical issue to the success of EV/HEV and renewable energy

  13. Characterization and optimization of cathodic conditions for H2O2 synthesis in microbial electrochemical cells

    EPA Science Inventory

    Cathode potential and O2 supply methods were investigated to improve H2O2 synthesis in an electrochemical cell, and optimal cathode conditions were applied for microbial electrochemical cells (MECs). Using aqueous O2 for the cathode significantly improved current density, but H2...

  14. Visualization of cellulose synthases in Arabidopsis secondary cell walls.

    PubMed

    Watanabe, Y; Meents, M J; McDonnell, L M; Barkwill, S; Sampathkumar, A; Cartwright, H N; Demura, T; Ehrhardt, D W; Samuels, A L; Mansfield, S D

    2015-10-01

    Cellulose biosynthesis in plant secondary cell walls forms the basis of vascular development in land plants, with xylem tissues constituting the vast majority of terrestrial biomass. We used plant lines that contained an inducible master transcription factor controlling xylem cell fate to quantitatively image fluorescently tagged cellulose synthase enzymes during cellulose deposition in living protoxylem cells. The formation of secondary cell wall thickenings was associated with a redistribution and enrichment of CESA7-containing cellulose synthase complexes (CSCs) into narrow membrane domains. The velocities of secondary cell wall-specific CSCs were faster than those of primary cell wall CSCs during abundant cellulose production. Dynamic intracellular of endomembranes, in combination with increased velocity and high density of CSCs, enables cellulose to be synthesized rapidly in secondary cell walls. PMID:26450210

  15. Organic electrochemical transistors for cell-based impedance sensing

    NASA Astrophysics Data System (ADS)

    Rivnay, Jonathan; Ramuz, Marc; Leleux, Pierre; Hama, Adel; Huerta, Miriam; Owens, Roisin M.

    2015-01-01

    Electrical impedance sensing of biological systems, especially cultured epithelial cell layers, is now a common technique to monitor cell motion, morphology, and cell layer/tissue integrity for high throughput toxicology screening. Existing methods to measure electrical impedance most often rely on a two electrode configuration, where low frequency signals are challenging to obtain for small devices and for tissues with high resistance, due to low current. Organic electrochemical transistors (OECTs) are conducting polymer-based devices, which have been shown to efficiently transduce and amplify low-level ionic fluxes in biological systems into electronic output signals. In this work, we combine OECT-based drain current measurements with simultaneous measurement of more traditional impedance sensing using the gate current to produce complex impedance traces, which show low error at both low and high frequencies. We apply this technique in vitro to a model epithelial tissue layer and show that the data can be fit to an equivalent circuit model yielding trans-epithelial resistance and cell layer capacitance values in agreement with literature. Importantly, the combined measurement allows for low biases across the cell layer, while still maintaining good broadband signal.

  16. Fabrication of solid oxide fuel cell by electrochemical vapor deposition

    DOEpatents

    Brian, Riley (Willimantic, CT); Szreders, Bernard E. (Oakdale, CT)

    1989-01-01

    In a high temperature solid oxide fuel cell (SOFC), the deposition of an impervious high density thin layer of electrically conductive interconnector material, such as magnesium doped lanthanum chromite, and of an electrolyte material, such as yttria stabilized zirconia, onto a porous support/air electrode substrate surface is carried out at high temperatures (approximately 1100.degree.-1300.degree. C.) by a process of electrochemical vapor deposition. In this process, the mixed chlorides of the specific metals involved react in the gaseous state with water vapor resulting in the deposit of an impervious thin oxide layer on the support tube/air electrode substrate of between 20-50 microns in thickness. An internal heater, such as a heat pipe, is placed within the support tube/air electrode substrate and induces a uniform temperature profile therein so as to afford precise and uniform oxide deposition kinetics in an arrangement which is particularly adapted for large scale, commercial fabrication of SOFCs.

  17. Fabrication of solid oxide fuel cell by electrochemical vapor deposition

    DOEpatents

    Riley, B.; Szreders, B.E.

    1988-04-26

    In a high temperature solid oxide fuel cell (SOFC), the deposition of an impervious high density thin layer of electrically conductive interconnector material, such as magnesium doped lanthanum chromite, and of an electrolyte material, such as yttria stabilized zirconia, onto a porous support/air electrode substrate surface is carried out at high temperatures (/approximately/1100/degree/ /minus/ 1300/degree/C) by a process of electrochemical vapor deposition. In this process, the mixed chlorides of the specific metals involved react in the gaseous state with water vapor resulting in the deposit of an impervious thin oxide layer on the support tube/air electrode substrate of between 20--50 microns in thickness. An internal heater, such as a heat pipe, is placed within the support tube/air electrode substrate and induces a uniform temperature profile therein so as to afford precise and uniform oxide deposition kinetics in an arrangement which is particularly adapted for large scale, commercial fabrication of SOFCs.

  18. Stabilizing metal components in electrodes of electrochemical cells

    DOEpatents

    Spengler, Charles J. (Murrysville, PA); Ruka, Roswell J. (Churchill Borough, PA)

    1989-01-01

    Disclosed is a method of reducing the removal or transfer into a gas phase of a current carrying metal in an apparatus, such as an electrochemical cell 2 having a porous fuel electrode 6 containing metal particles 11, where the metal is subject to removal or transfer into a gaseous phase, the method characterized in that (1) a metal organic compound that decomposes to form an electronically conducting oxide coating when heated is applied to the metal and porous electrode, and (2) the compound on the metal is then heated to a temperature sufficient to decompose the compound into an oxide coating 13 by increasing the temperature at a rate that is longer than 1 hour between room temperature and 600.degree. C., resulting in at least one continuous layer 13, 14 of the oxide coating on the metal.

  19. Nanopillar based electrochemical biosensor for monitoring microfluidic based cell culture

    NASA Astrophysics Data System (ADS)

    Gangadharan, Rajan

    In-vitro assays using cultured cells have been widely performed for studying many aspects of cell biology and cell physiology. These assays also form the basis of cell based sensing. Presently, analysis procedures on cell cultures are done using techniques that are not integrated with the cell culture system. This approach makes continuous and real-time in-vitro measurements difficult. It is well known that the availability of continuous online measurements for extended periods of time will help provide a better understanding and will give better insight into cell physiological events. With this motivation we developed a highly sensitive, selective and stable microfluidic electrochemical glucose biosensor to make continuous glucose measurements in cell culture media. The performance of the microfluidic biosensor was enhanced by adding 3D nanopillars to the electrode surfaces. The microfluidic glucose biosensor consisted of three electrodes---Enzyme electrode, Working electrode, and Counter electrode. All these electrodes were enhanced with nanopillars and were optimized in their respective own ways to obtain an effective and stable biosensing device in cell culture media. For example, the 'Enzyme electrode' was optimized for enzyme immobilization via either a polypyrrole-based or a self-assembled-monolayer-based immobilization method, and the 'Working electrode' was modified with Prussian Blue or electropolymerized Neutral Red to reduce the working potential and also the interference from other interacting electro-active species. The complete microfluidic biosensor was tested for its ability to monitor glucose concentration changes in cell culture media. The significance of this work is multifold. First, the developed device may find applications in continuous and real-time measurements of glucose concentrations in in-vitro cell cultures. Second, the development of a microfluidic biosensor will bring technical know-how toward constructing continuous glucose monitoring devices. Third, the methods used to develop 3D electrodes incorporated with nanopillars can be used for other applications such as neural probes, fuel cells, solar cells etc., and finally, the knowledge obtained from the immobilization of enzymes onto nanostructures sheds some new insight into nanomaterial/biomolecule interactions.

  20. Method for transferring thermal energy and electrical current in thin-film electrochemical cells

    DOEpatents

    Rouillard, Roger (Beloeil, CA); Domroese, Michael K. (South St. Paul, MN); Hoffman, Joseph A. (Minneapolis, MN); Lindeman, David D. (Hudson, WI); Noel, Joseph-Robert-Gaetan (St-Hubert, CA); Radewald, Vern E. (Austin, TX); Ranger, Michel (Lachine, CA); Sudano, Anthony (Laval, CA); Trice, Jennifer L. (Eagan, MN); Turgeon, Thomas A. (Fridley, MN)

    2003-05-27

    An improved electrochemical generator is disclosed. The electrochemical generator includes a thin-film electrochemical cell which is maintained in a state of compression through use of an internal or an external pressure apparatus. A thermal conductor, which is connected to at least one of the positive or negative contacts of the cell, conducts current into and out of the cell and also conducts thermal energy between the cell and thermally conductive, electrically resistive material disposed on a vessel wall adjacent the conductor. The thermally conductive, electrically resistive material may include an anodized coating or a thin sheet of a plastic, mineral-based material or conductive polymer material. The thermal conductor is fabricated to include a resilient portion which expands and contracts to maintain mechanical contact between the cell and the thermally conductive material in the presence of relative movement between the cell and the wall structure. The electrochemical generator may be disposed in a hermetically sealed housing.

  1. Electrode heat balances of electrochemical cells: Application to water electrolysis

    SciTech Connect

    Ito, Y.; Forland, T.; Kaiya, H.; Ratkja, S.K.; Yoshizawa, S.

    1984-11-01

    Irreversible thermodynamics has been used to describe electrode heat balances of electrochemical cells. The specific example of electrolysis of water in molten sodium hydroxide is chosen for the purpose of illustration. Experimental data are presented for this system. The importance of a distinction between time and chargedependent changes in entropy is pointed out. Only changes of the last type contribute to cell EMF's. The relation between EMF of thermocells, the temperature coefficient of an isothermal cell, and the electrode heat balances are discussed particularly. Results show a reasonably good agreement between theoretical predictions and experimental observations. With partial pressures of hydrogen and water vapor in the cathodic compartment of 0.8 and 0.2 atm, respectively, 63 kJ is evolved, and with partial pressures of oxygen and water vapor in the anodic compartment of 0.8 and 0.2 atm, respectively, 72 kJ is absorbed during the passage of 1F of current at 623 K.

  2. Electrolytes including fluorinated solvents for use in electrochemical cells

    DOEpatents

    Tikhonov, Konstantin; Yip, Ka Ki; Lin, Tzu-Yuan

    2015-07-07

    Provided are electrochemical cells and electrolytes used to build such cells. The electrolytes include ion-supplying salts and fluorinated solvents capable of maintaining single phase solutions with the salts at between about -30.degree. C. to about 80.degree. C. The fluorinated solvents, such as fluorinated carbonates, fluorinated esters, and fluorinated esters, are less flammable than their non-fluorinated counterparts and increase safety characteristics of cells containing these solvents. The amount of fluorinated solvents in electrolytes may be between about 30% and 80% by weight not accounting weight of the salts. Fluorinated salts, such as fluoroalkyl-substituted LiPF.sub.6, fluoroalkyl-substituted LiBF.sub.4 salts, linear and cyclic imide salts as well as methide salts including fluorinated alkyl groups, may be used due to their solubility in the fluorinated solvents. In some embodiments, the electrolyte may also include a flame retardant, such as a phosphazene or, more specifically, a cyclic phosphazene and/or one or more ionic liquids.

  3. Eliminating degradation in solid oxide electrochemical cells by reversible operation.

    PubMed

    Graves, Christopher; Ebbesen, Sune Dalgaard; Jensen, Søren Højgaard; Simonsen, Søren Bredmose; Mogensen, Mogens Bjerg

    2015-02-01

    One promising energy storage technology is the solid oxide electrochemical cell (SOC), which can both store electricity as chemical fuels (electrolysis mode) and convert fuels to electricity (fuel-cell mode). The widespread use of SOCs has been hindered by insufficient long-term stability, in particular at high current densities. Here we demonstrate that severe electrolysis-induced degradation, which was previously believed to be irreversible, can be completely eliminated by reversibly cycling between electrolysis and fuel-cell modes, similar to a rechargeable battery. Performing steam electrolysis continuously at high current density (1 A cm(-2)), initially at 1.33 V (97% energy efficiency), led to severe microstructure deterioration near the oxygen-electrode/electrolyte interface and a corresponding large increase in ohmic resistance. After 4,000 h of reversible cycling, however, no microstructural damage was observed and the ohmic resistance even slightly improved. The results demonstrate the viability of applying SOCs for renewable electricity storage at previously unattainable reaction rates, and have implications for our fundamental understanding of degradation mechanisms that are usually assumed to be irreversible. PMID:25532070

  4. Eliminating degradation in solid oxide electrochemical cells by reversible operation

    NASA Astrophysics Data System (ADS)

    Graves, Christopher; Ebbesen, Sune Dalgaard; Jensen, Søren Højgaard; Simonsen, Søren Bredmose; Mogensen, Mogens Bjerg

    2015-02-01

    One promising energy storage technology is the solid oxide electrochemical cell (SOC), which can both store electricity as chemical fuels (electrolysis mode) and convert fuels to electricity (fuel-cell mode). The widespread use of SOCs has been hindered by insufficient long-term stability, in particular at high current densities. Here we demonstrate that severe electrolysis-induced degradation, which was previously believed to be irreversible, can be completely eliminated by reversibly cycling between electrolysis and fuel-cell modes, similar to a rechargeable battery. Performing steam electrolysis continuously at high current density (1 A cm-2), initially at 1.33 V (97% energy efficiency), led to severe microstructure deterioration near the oxygen-electrode/electrolyte interface and a corresponding large increase in ohmic resistance. After 4,000 h of reversible cycling, however, no microstructural damage was observed and the ohmic resistance even slightly improved. The results demonstrate the viability of applying SOCs for renewable electricity storage at previously unattainable reaction rates, and have implications for our fundamental understanding of degradation mechanisms that are usually assumed to be irreversible.

  5. The Sodium Exposure Test Cell to determine operating parameters for AMTEC electrochemical cells

    SciTech Connect

    Ryan, M.A.; Williams, R.M.; Lara, L.; Cortez, R.H.; Homer, M.L.; Shields, V.B.; Miller, J.; Manatt, K.S.

    1998-07-01

    The Sodium Exposure Test Cell (SETC) is a non-power producing cell which has been developed to evaluate and test components of the electrochemical cell in an Alkali Metal Thermal to Electric Converter. Performance and time dependence of performance of the electrode and the electrolyte in AMTEC cells can be tested in an SETC, and performance parameters which correlate with those taken from AMTEC operation can be calculated from data taken in an SETC. The components of the AMTEC electrochemical cell which are evaluated in an SETC are the electrode, {beta}{double{underscore}prime}-alumina solid electrolyte (BASE), the current collection network, and the containment. The components are held in low pressure sodium vapor at a temperature which reflects their operating conditions in an AMTEC device, and operating parameters determined. Electrodes and BASE are evaluated by measuring current-voltage (IV) characteristics and using Electrochemical Impedance Spectroscopy (EIS). Using these techniques, electrode performance parameters such as the exchange current (B), the morphology factor (G), and contact resistance between electrode and current collection network can be determined. The ionic conductivity (s) of BASE can also be determined. IV curves and EIS measurements are made at intervals over periods of several hundreds of hours in order to evaluate degradation of AMTEC electrochemical cell components. Electrode and BASE are analyzed after an SETC experiment using Scanning Electron Microscopy, Electron Dispersive Spectroscopy, and X-Ray Diffraction. These techniques allow evaluation of interaction of materials and changes in the composition and structure of materials. The purpose of these experiments is determination of the changes of operating parameters as a function of time in order to predict the operating lifetime of AMTEC cells.

  6. Supported liquid membrane electrochemical separators

    DOEpatents

    Pemsler, J. Paul (Lexington, MA); Dempsey, Michael D. (Revere, MA)

    1986-01-01

    Supported liquid membrane separators improve the flexibility, efficiency and service life of electrochemical cells for a variety of applications. In the field of electrochemical storage, an alkaline secondary battery with improved service life is described in which a supported liquid membrane is interposed between the positive and negative electrodes. The supported liquid membranes of this invention can be used in energy production and storage systems, electrosynthesis systems, and in systems for the electrowinning and electrorefining of metals.

  7. Air electrode material for high temperature electrochemical cells

    DOEpatents

    Ruka, Roswell J. (Churchill Boro, PA)

    1985-01-01

    Disclosed is a solid solution with a perovskite-like crystal structure having the general formula La.sub.1-x-w (M.sub.L).sub.x (Ce).sub.w (M.sub.S1).sub.1-y (M.sub.S2).sub.y O.sub.3 where M.sub.L is Ca, Sr, Ba, or mixtures thereof, M.sub.S1 is Mn, Cr, or mixtures thereof and M.sub.S2 is Ni, Fe, Co, Ti, Al, In, Sn, Mg, Y, Nb, Ta, or mixtures thereof, w is about 0.05 to about 0.25, x+w is about 0.1 to about 0.7, and y is 0 to about 0.5. In the formula, M.sub.L is preferably Ca, w is preferably 0.1 to 0.2, x+w is preferably 0.4 to 0.7, and y is preferably 0. The solid solution can be used in an electrochemical cell where it more closely matches the thermal expansion characteristics of the support tube and electrolyte of the cell.

  8. Support tube for high temperature solid electrolyte electrochemical cell

    DOEpatents

    Ruka, Roswell J. (Churchill Boro, PA); Rossing, Barry R. (Pittsburgh, PA)

    1986-01-01

    Disclosed is a compound having a fluorite-like structure comprising a solid solution having the general formula [(ZrO.sub.2).sub.1-x (MO.sub.s).sub.x ].sub.1-y [(La.sub.m A.sub.1-m).sub.2-z (Mn.sub.n B.sub.1-n).sub.z O.sub.r ].sub.y where MO.sub.5 is an oxide selected from the group consisting of calcia, yttria, rare earth oxides, and mixtures thereof, x is about 0.1 to 0.3, y is about 0.005 to about 0.06, z is about 0.1 to about 1.9, A is yttrium, rare earth element, alkaline earth element, or mixture thereof, B is iron, nickel, cobalt, or mixture thereof, m is 0.3 to 1, n is 0.5 to 1, and r is 2 to 4. A porous tube made from such a composition can be coated with an electrically conducting mixed oxide electrode such as lanthanum manganite, and can be used in making high temperature electrochemical cells such as solid electrolyte fuel cells.

  9. Electrochemical in situ reaction cell for X-ray scattering, diffraction and spectroscopy.

    PubMed

    Braun, A; Shrout, S; Fowlks, A C; Osaisai, B A; Seifert, S; Granlund, E; Cairns, E J

    2003-07-01

    A versatile electrochemical in situ reaction cell for long-term hard X-ray experiments on battery electrodes is described. Applications include the small-angle scattering, diffraction and absorption spectroscopy of lithium manganese oxide electrodes. PMID:12824932

  10. Diffuse-charge effects on the transient response of electrochemical cells

    E-print Network

    van Soestbergen, M.

    We present theoretical models for the time-dependent voltage of an electrochemical cell in response to a current step, including effects of diffuse charge (or “space charge”) near the electrodes on Faradaic reaction kinetics. ...

  11. Direct In Vivo Electrochemical Detection of Haemoglobin in Red Blood Cells

    E-print Network

    Toh, Rou Jun

    The electrochemical behavior of iron ion in haemoglobin provides insight to the chemical activity in the red blood cell which is important in the field of hematology. Herein, the detection of haemoglobin in human red blood ...

  12. Electrochemical in-situ reaction cell for X-ray scattering, diffraction and spectroscopy

    SciTech Connect

    Braun, Artur; Granlund, Eric; Cairns, Elton J.

    2003-01-27

    An electrochemical in-situ reaction cell for hard X-ray experiments with battery electrodes is described. Applications include the small angle scattering, diffraction, and near-edge spectroscopy of lithium manganese oxide electrodes.

  13. Cycle life test of secondary spacecraft cells

    NASA Technical Reports Server (NTRS)

    Harkness, J. D.

    1980-01-01

    The results of the life cycling program on rechargeable calls are reported. Information on required data, the use of which the data will be put, application details, including orbital description, charge control methods, load rquirements, etc., are given. Cycle tests were performed on 660 sealed, nickel cadmium cells. The cells consisted of seven sample classifications ranging form 3.0 to 20 amp. hours. Nickel cadmium, silver cadmium, and silver zinc sealed cells, excluding synchronous orbit and accelerated test packs were added. The capacities of the nickel cadmium cells, the silver cadmium and the silver zinc cells differed in range of amp hrs. The cells were cylced under different load, charge control, and temperature conditions. All cell packs are recharged by use of a pack voltage limit. All charging is constant current until the voltage limit is reached.

  14. Solid electrolyte-electrode system for an electrochemical cell

    DOEpatents

    Tuller, Harry L. (Wellesley, MA); Kramer, Steve A. (Somerville, MA); Spears, Marlene A. (Woburn, MA)

    1995-01-01

    An electrochemical device including a solid electrolyte and solid electrode composed of materials having different chemical compositions and characterized by different electrical properties but having the same crystalline phase is provided. A method for fabricating an electrochemical device having a solid electrode and solid electrolyte characterized by the same crystalline phase is also provided.

  15. Solid electrolyte-electrode system for an electrochemical cell

    DOEpatents

    Tuller, H.L.; Kramer, S.A.; Spears, M.A.

    1995-04-04

    An electrochemical device including a solid electrolyte and solid electrode composed of materials having different chemical compositions and characterized by different electrical properties but having the same crystalline phase is provided. A method for fabricating an electrochemical device having a solid electrode and solid electrolyte characterized by the same crystalline phase is also provided. 17 figures.

  16. Paper-Based Electrochemical Cell Coupled to Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Liu, Yao-Min; Perry, Richard H.

    2015-08-01

    On-line coupling of electrochemistry (EC) to mass spectrometry (MS) is a powerful approach for identifying intermediates and products of EC reactions in situ. In addition, EC transformations have been used to increase ionization efficiency and derivatize analytes prior to MS, improving sensitivity and chemical specificity. Recently, there has been significant interest in developing paper-based electroanalytical devices as they offer convenience, low cost, versatility, and simplicity. This report describes the development of tubular and planar paper-based electrochemical cells (P-EC) coupled to sonic spray ionization (SSI) mass spectrometry (P-EC/SSI-MS). The EC cells are composed of paper sandwiched between two mesh stainless steel electrodes. Analytes and reagents can be added directly to the paper substrate along with electrolyte, or delivered via the SSI microdroplet spray. The EC cells are decoupled from the SSI source, allowing independent control of electrical and chemical parameters. We utilized P-EC/SSI-MS to characterize various EC reactions such as oxidations of cysteine, dopamine, polycyclic aromatic hydrocarbons, and diphenyl sulfide. Our results show that P-EC/SSI-MS has the ability to increase ionization efficiency, to perform online EC transformations, and to capture intermediates of EC reactions with a response time on the order of hundreds of milliseconds. The short response time allowed detection of a deprotonated diphenyl sulfide intermediate, which experimentally confirms a previously proposed mechanism for EC oxidation of diphenyl sulfide to pseudodimer sulfonium ion. This report introduces paper-based EC/MS via development of two device configurations (tubular and planar electrodes), as well as discusses the capabilities, performance, and limitations of the technique.

  17. Electrochemical machining analysis on grid cathode composed of square cells

    NASA Astrophysics Data System (ADS)

    Lu, Yonghua; Liu, Kai; Zhao, Dongbiao

    2013-07-01

    During the electrochemical machining (ECM), the cathodes designed by the existing methods are mainly unitary cathodes, which can be only used to produce the workpieces with the same shapes. However, there are few researches on designing cathodes for machining the different workpieces with the different surfaces. This paper presents the grid cathode composed of the square cells to produce the workpieces with different shapes. Three types of the square cells, 2.5 mm×2.5 mm, 3 mm×3 mm, and 4 mm×4 mm, are utilized to construct the plane, the slant, and the blade cathode. The material of the cathode and the anode is CrNi18Ti9, and the ingredient of electrolyte is 15% NaCl and 15% NaNO3. The machining equilibrium machining current and time are acquired and analyzed, the machining process and the workpiece quality are compared between using the grid cathode and the unitary cathode. Moreover, the machining errors on the workpiece surface are measured and analyzed, and the error reasons are traced and discussed to obtain the better surface quality of the workpiece. The experiment and analysis results show that the grid cathode can be used to manufacture the workpieces with complex shapes in certain range of the error. The workpiece quality improves with the size of the square cell being reduced, and if the square element is small enough, the workpiece quality is almost equal to the one machined by the unitary cathode. The proposed research realizes a single cathode machining the different workpieces with the different surfaces.

  18. Evaluation program for secondary spacecraft cells

    NASA Technical Reports Server (NTRS)

    Harkness, J. D.

    1975-01-01

    The cycle life tests to determine the performance capabilities of packs of cells under different loads and temperature conditions are reported. Results are summarized, and the failure of 14 failed cells is analyzed. It was found that the main cause of failure was separator deterioration and migration of the negative plate material.

  19. Recovery and electrochemical performance in lithium secondary batteries of biochar derived from rice straw.

    PubMed

    Ryu, Da-Jeong; Oh, Rye-Gyeong; Seo, Yong-Deuk; Oh, Seok-Young; Ryu, Kwang-Sun

    2015-07-01

    Renewable biomass has attracted great attention for the production of biooil, biogas, and biochar, a carbon residual applicable for carbon sequestration and environmental remediation. Rice straw is one of the most common biomasses among agricultural wastes in South Korea. As part of our advanced and environmentally friendly research, we applied biochar derived from rice straw as the anode material for lithium-ion batteries (LIBs). Porous carbons with a high surface area were prepared from rice straw. Such porous carbons have exhibited particularly large reversible capacity and hence proven to be a candidate anode material for high-rate and high-capacity LIBs. Rice straw-derived biochars were synthesized at four different temperatures: 400, 550, 700, and 900 °C. The surface was modified by using HCl and H2O2 on the 550 °C biochar in order to increase the surface area. The resulting biochar was characterized by X-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM). The surface area was measured by Brunauer-Emmett-Teller (BET) method. The electrochemical characterizations were investigated by galvanostatic charge-discharge (CD) curves, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). All samples exhibited reversible capacities of below 200 mAh g(-1). The surface-modified biochars exhibited improved cycle performance. Surface modification using HCl showed better cycle performance than H2O2. However, the capacities of the treated 550 °C biochar were similar to those of non-surface-modified biochar. PMID:25821037

  20. Graphene-based Electrochemical Energy Conversion and Storage: Fuel cells, Supercapacitors and Lithium Ion Batteries

    SciTech Connect

    Hou, Junbo; Shao, Yuyan; Ellis, Michael A.; Moore, Robert; Yi, Baolian

    2011-09-14

    Graphene has attracted extensive research interest due to its strictly 2-dimensional (2D) structure, which results in its unique electronic, thermal, mechanical, and chemical properties and potential technical applications. These remarkable characteristics of graphene, along with the inherent benefits of a carbon material, make it a promising candidate for application in electrochemical energy devices. This article reviews the methods of graphene preparation, introduces the unique electrochemical behavior of graphene, and summarizes the recent research and development on graphene-based fuel cells, supercapacitors and lithium ion batteries. In addition, promising areas are identified for the future development of graphene-based materials in electrochemical energy conversion and storage systems.

  1. In situ solid-state NMR spectroscopy of electrochemical cells: batteries, supercapacitors, and fuel cells.

    PubMed

    Blanc, Frédéric; Leskes, Michal; Grey, Clare P

    2013-09-17

    Electrochemical cells, in the form of batteries (or supercapacitors) and fuel cells, are efficient devices for energy storage and conversion. These devices show considerable promise for use in portable and static devices to power electronics and various modes of transport and to produce and store electricity both locally and on the grid. For example, high power and energy density lithium-ion batteries are being developed for use in hybrid electric vehicles where they improve the efficiency of fuel use and help to reduce greenhouse gas emissions. To gain insight into the chemical reactions involving the multiple components (electrodes, electrolytes, interfaces) in the electrochemical cells and to determine how cells operate and how they fail, researchers ideally should employ techniques that allow real-time characterization of the behavior of the cells under operating conditions. This Account reviews the recent use of in situ solid-state NMR spectroscopy, a technique that probes local structure and dynamics, to study these devices. In situ NMR studies of lithium-ion batteries are performed on the entire battery, by using a coin cell design, a flat sealed plastic bag, or a cylindrical cell. The battery is placed inside the NMR coil, leads are connected to a potentiostat, and the NMR spectra are recorded as a function of state of charge. (7)Li is used for many of these experiments because of its high sensitivity, straightforward spectral interpretation, and relevance to these devices. For example, (7)Li spectroscopy was used to detect intermediates formed during electrochemical cycling such as LixC and LiySiz species in batteries with carbon and silicon anodes, respectively. It was also used to observe and quantify the formation and growth of metallic lithium microstructures, which can cause short circuits and battery failure. This approach can be utilized to identify conditions that promote dendrite formation and whether different electrolytes and additives can help prevent dendrite formation. The in situ method was also applied to monitor (by (11)B NMR) electrochemical double-layer formation in supercapacitors in real time. Though this method is useful, it comes with challenges. The separation of the contributions from the different cell components in the NMR spectra is not trivial because of overlapping resonances. In addition, orientation-dependent NMR interactions, including the spatial- and orientation-dependent bulk magnetic susceptibility (BMS) effects, can lead to resonance broadening. Efforts to understand and mitigate these BMS effects are discussed in this Account. The in situ NMR investigation of fuel cells initially focused on the surface electrochemistry at the electrodes and the electrochemical oxidation of methanol and CO to CO2 on the Pt cathode. On the basis of the (13)C and (195)Pt NMR spectra of the adsorbates and electrodes, CO adsorbed on Pt and other reaction intermediates and complete oxidation products were detected and their mode of binding to the electrodes investigated. Appropriate design and engineering of the NMR hardware has allowed researchers to integrate intact direct methanol fuel cells into NMR probes. Chemical transformations of the circulating methanol could be followed and reaction intermediates could be detected in real time by either (2)H or (13)C NMR spectroscopy. By use of the in situ NMR approach, factors that control fuel cell performance, such as methanol cross over and catalyst performance, were identified. PMID:24041242

  2. Cell and current collector felt arrangement for solid oxide electrochemical cell combinations

    DOEpatents

    Reichner, Philip (Plum Boro, PA)

    1988-01-01

    A solid electrolyte electrochemical cell combination 1 is made, comprising an annular, axially elongated, inner electrode 2 containing at least one interior gas feed conduit 3; annular solid electrolyte segments 4 around and covering portions of the inner electrode; annular outer electrode segments 6 around and covering portions of the electrolyte segments; electronically conducting, non-porous, interconnection material 5 disposed between electrolyte segments and in contact with the inner electrode, and electronically conducting, porous, metal fiber current collector felts 7 disposed on top of the non-porous interconnect material and outer electrode segments, where both the non-porous interconnect material and the porous metal felts are disposed circumferentially about the cell, transversely to the axial length of the cell and the inner electrode is continuous for the entire axial length of the cell combination.

  3. An electrochemical cell for the efficient turn around of wafer working electrodes

    NASA Astrophysics Data System (ADS)

    Wozniak, Nicholas R.; Frey, Alyssa A.; Osterbur, Lucas W.; Boman, Timothy S.; Hampton, Jennifer R.

    2010-03-01

    We present a new design for an electrochemical cell for use with wafer working electrodes. The key feature of the design is the use of half turn thumb screws to form a liquid-tight seal between an o-ring and the sample surface. The assembly or disassembly of the cell requires a half turn of each thumb screw, which facilitates the quick turn around of wafer samples. The electrochemical performance of the cell is demonstrated by cyclic voltammetry and double step chronoamperometry measurements of the ferricyanide/ferrocyanide couple.

  4. An electrochemical cell for the efficient turn around of wafer working electrodes.

    PubMed

    Wozniak, Nicholas R; Frey, Alyssa A; Osterbur, Lucas W; Boman, Timothy S; Hampton, Jennifer R

    2010-03-01

    We present a new design for an electrochemical cell for use with wafer working electrodes. The key feature of the design is the use of half turn thumb screws to form a liquid-tight seal between an o-ring and the sample surface. The assembly or disassembly of the cell requires a half turn of each thumb screw, which facilitates the quick turn around of wafer samples. The electrochemical performance of the cell is demonstrated by cyclic voltammetry and double step chronoamperometry measurements of the ferricyanide/ferrocyanide couple. PMID:20370197

  5. Secondary solid cancer screening following hematopoietic cell transplantation.

    PubMed

    Inamoto, Y; Shah, N N; Savani, B N; Shaw, B E; Abraham, A A; Ahmed, I A; Akpek, G; Atsuta, Y; Baker, K S; Basak, G W; Bitan, M; DeFilipp, Z; Gregory, T K; Greinix, H T; Hamadani, M; Hamilton, B K; Hayashi, R J; Jacobsohn, D A; Kamble, R T; Kasow, K A; Khera, N; Lazarus, H M; Malone, A K; Lupo-Stanghellini, M T; Margossian, S P; Muffly, L S; Norkin, M; Ramanathan, M; Salooja, N; Schoemans, H; Wingard, J R; Wirk, B; Wood, W A; Yong, A; Duncan, C N; Flowers, M E D; Majhail, N S

    2015-08-01

    Hematopoietic stem cell transplant (HCT) recipients have a substantial risk of developing secondary solid cancers, particularly beyond 5 years after HCT and without reaching a plateau overtime. A working group was established through the Center for International Blood and Marrow Transplant Research and the European Group for Blood and Marrow Transplantation with the goal to facilitate implementation of cancer screening appropriate to HCT recipients. The working group reviewed guidelines and methods for cancer screening applicable to the general population and reviewed the incidence and risk factors for secondary cancers after HCT. A consensus approach was used to establish recommendations for individual secondary cancers. The most common sites include oral cavity, skin, breast and thyroid. Risks of cancers are increased after HCT compared with the general population in skin, thyroid, oral cavity, esophagus, liver, nervous system, bone and connective tissues. Myeloablative TBI, young age at HCT, chronic GVHD and prolonged immunosuppressive treatment beyond 24 months were well-documented risk factors for many types of secondary cancers. All HCT recipients should be advised of the risks of secondary cancers annually and encouraged to undergo recommended screening based on their predisposition. Here we propose guidelines to help clinicians in providing screening and preventive care for secondary cancers among HCT recipients. PMID:25822223

  6. Electrochemical Polishing of Silverware: A Demonstration of Voltaic and Galvanic Cells

    ERIC Educational Resources Information Center

    Ivey, Michelle M.; Smith, Eugene T.

    2008-01-01

    In this demonstration, the students use their knowledge of electrochemistry to determine that tarnish can be removed from silverware by electrochemically converting it back to silver using items commonly available in the kitchen: aluminum foil and baking soda. In addition to using this system as an example of a galvanic cell, an electrolytic cell

  7. Method and device for the detection of phenol and related compounds. [in an electrochemical cell

    NASA Technical Reports Server (NTRS)

    Schiller, J. G.; Liu, C. C. (inventors)

    1979-01-01

    A method is described which permits the selective oxidation and potentiometric detection of phenol and related compounds in an electrochemical cell. An anode coated with a gel immobilized oxidative enzyme and a cathode are each placed in an electrolyte solution. The potential of the cell is measured by a potentiometer connected to the electrodes.

  8. Electrochemical decolorization of methyl orange powered by bioelectricity from single-chamber microbial fuel cells.

    PubMed

    Zhang, Baogang; Wang, Zhijun; Zhou, Xiang; Shi, Chunhong; Guo, Huaming; Feng, Chuanping

    2015-04-01

    Methyl orange (MO), a typical azo dye, is a well-known recalcitrant pollutant in dye wastewater. An aeration electrochemical system with single-chamber microbial fuel cell (MFC) as renewable power sources is proposed for MO decolorization. The enhanced color removal efficiency up to 90.4% within 360 min is observed with voltage across the aeration electrolytic reactor fixed at 700 mV. The results from gas chromatography-mass spectrometry (GC-MS) analysis indicate the destruction of MO, with generation of low molecular weight compounds such as benzene derivatives. Comparison experiments imply the indirect electrochemical oxidation of MO by generated H2O2 is mainly responsible for MO decolorization in present study. This work offers a cost-effective electrochemical method for enhancing electrochemical degradation of dyes with bioelectricity generated from MFCs. PMID:25661516

  9. Hierarchical Co@C Nanoflowers: Synthesis and Electrochemical Properties as an Advanced Negative Material for Alkaline Secondary Batteries.

    PubMed

    Li, Li; Ma, Jianmin; Zhang, Zichao; Cao, Bingqiang; Wang, Yijing; Jiao, Lifang; Yuan, Huatang

    2015-11-01

    Hierarchical Co@C nanoflowers have been facilely synthesized via a simple route based on a low-temperature solid-phase reaction. The obtained hierarchical Co@C nanoflowers, each constructed of a number of nanosheets, display a three-dimensional architecture with an average grain size of about 300 nm. The electrochemical properties of the Co@C nanoflowers as the negative material for Ni/Co cells have been systemically researched. In particular, Co@C material exhibits high discharge-specific capacity and good cycling stability. The discharge-specific capacity of our Co@C-3 electrode can reach 612.1 mA h g(-1), and the specific capacity of 415.3 mA h g(-1) is retained at a current density of 500 mA g(-1) after 120 cycles, indicating its great potential for high-performance Ni/Co batteries. Interestingly, the as-synthesized Co@C electrode also exhibits favorable rate capability. These desirable properties can be attributed to porous pathways, which allow fast transportation of ions and electrons and easy accessibility to the electrolyte. The dominant electrochemical mechanism of Co@C can be attributed to the reduction-oxidation reaction between metallic cobalt and cobalt hydroxide in alkaline solution. PMID:26460934

  10. Electrochemical impedance spectrum frequency optimization of bitter taste cell-based sensors.

    PubMed

    Hui, Guo-Hua; Ji, Peng; Mi, Shan-Shan; Deng, Shao-Ping

    2013-09-15

    Electrochemical impedance spectrum frequency optimization to bitter taste receptor cell-based sensors is discussed in this paper. The bitter taste receptor cells (the enteroendocrine STC-1 cells and the ICR mouse isolated taste bud cells) are cultured on carbon screen printed electrodes and used as sensing elements. The HEK-293 cells and dead isolated ICR mouse taste bud cells, without bitter taste receptor expression, are used in negative control experiments. The electrochemical impedance spectrum data is recorded and processed by bistable stochastic resonance for signal-to-noise ratio analysis. The bitter taste receptor cell-based sensor selectively responds to bitter tastants. The tastants species and concentrations can be decided by signal-to-noise ratio parameters. The signal-to-noise ratio eigen peak changes with the shift of electrochemical impedance spectrum frequencies. ICR mouse isolated taste bud cell-based sensor presents bitter tastants perception abilities. 9kHz is the optimal frequency for STC-1 cell-based sensor measurement. For isolated ICR mouse taste bud cells, 1.2kHz is the optimal frequency. Negative control experiments results indicate that cells with no taste receptor expression have no discriminating ability for tastant even if they are modulated by different frequencies. The taste cell-based sensor is of great practical value. PMID:23578970

  11. Overcharge and overdischarge protection of ambient temperature secondary lithium cells

    NASA Technical Reports Server (NTRS)

    Huang, Chen-Kuo (inventor); Surampudi, Subbarao (inventor); Attia, Alan I. (inventor); Halpert, Gerald (inventor)

    1994-01-01

    A cathode additive is provided for protecting an ambient temperature secondary lithium cell from overcharging or overdischarging. The cathode additive is chosen to create an upper voltage plateau which is slightly higher than a characteristic charge cutoff voltage of the cathode of the cell. The cathode additive additionally creates a lower voltage plateau which is slightly lower than the characteristic discharge cutoff voltage of the cell. Preferably, the cathode additive is a transition metal oxide or a sulfide and may, for example, include a mixture of Li2Mn2O4 and Li(0.1)MoO2.

  12. Enhanced Electrochemical Catalytic Efficiencies of Electrochemically Deposited Platinum Nanocubes as a Counter Electrode for Dye-Sensitized Solar Cells.

    PubMed

    Wei, Yu-Hsuan; Tsai, Ming-Chi; Ma, Chen-Chi M; Wu, Hsuan-Chung; Tseng, Fan-Gang; Tsai, Chuen-Horng; Hsieh, Chien-Kuo

    2015-12-01

    Platinum nanocubes (PtNCs) were deposited onto a fluorine-doped tin oxide glass by electrochemical deposition (ECD) method and utilized as a counter electrode (CE) for dye-sensitized solar cells (DSSCs). In this study, we controlled the growth of the crystalline plane to synthesize the single-crystal PtNCs at room temperature. The morphologies and crystalline nanostructure of the ECD PtNCs were examined by field emission scanning electron microscopy and high-resolution transmission electron microscopy. The surface roughness of the ECD PtNCs was examined by atomic force microscopy. The electrochemical properties of the ECD PtNCs were analyzed by cyclic voltammetry, Tafel polarization, and electrochemical impedance spectra. The Pt loading was examined by inductively coupled plasma mass spectrometry. The DSSCs were assembled via an N719 dye-sensitized titanium dioxide working electrode, an iodine-based electrolyte, and a CE. The photoelectric conversion efficiency (PCE) of the DSSCs with the ECD PtNC CE was examined under the illumination of AM 1.5 (100 mWcm(-2)). The PtNCs in this study presented a single-crystal nanostructure that can raise the electron mobility to let up the charge-transfer impedance and promote the charge-transfer rate. In this work, the electrocatalytic mass activity (MA) of the Pt film and PtNCs was 1.508 and 4.088 mAmg(-1), respectively, and the MA of PtNCs was 2.71 times than that of the Pt film. The DSSCs with the pulse-ECD PtNC CE showed a PCE of 6.48 %, which is higher than the cell using the conventional Pt film CE (a PCE of 6.18 %). In contrast to the conventional Pt film CE which is fabricated by electron beam evaporation method, our pulse-ECD PtNCs maximized the Pt catalytic properties as a CE in DSSCs. The results demonstrated that the PtNCs played a good catalyst for iodide/triiodide redox couple reactions in the DSSCs and provided a potential strategy for electrochemical catalytic applications. PMID:26625891

  13. Electrochemical properties of the NiS powder prepared by co-precipitation method for lithium secondary battery.

    PubMed

    Ryu, Ho-Suk; Ha, Chung-Wan; Ji, Seong-Yong; Ahn, In-Shup; Ahn, Jou-Hyeon; Ahn, Hyo-Jun; Kim, Ki-Won

    2014-10-01

    We synthesized two nickel sulfide powders by simple method. One is nickel sulfide powder (CNS) by co-precipitation is composed of nano-sized nickel sulfides as NiS and NIS2. The other is nickel sulfide powder (HNS) by heat-treatment of CNS is composed nano-sized NIS. The electrode using CNS has a high first discharge capacity of 600 mA h g(-1) at 0.5 C and the discharge capacity after 20th cycle is 312 mA h g(-1). The electrode using HNS has a high first discharge capacity of 551 mA h g(-1) at 0.5 C and has the discharge capacity of 412 mA h g(-1) after 50th. The discharge rate capability has over 92% at 1 C versus 0.2 C. The nano-sized nickel sulfides are synthesized by simple co-precipitation method has good electrochemical properties such as high first discharge capacity, good cycle life and good rate capability for lithium secondary battery. PMID:25942899

  14. Improved alkaline earth-oxyhalide electrochemical cell for low-temperature use

    SciTech Connect

    Binder, M.; Walker, C.W.

    1988-05-20

    This invention relates in general to an alkaline earth-oxyhalide electrochemical cell and in particular, to an improved alkaline earth oxyhalide electrochemical cell for low temperature use. A typical cell includes a calcium anode, 1M Ca(AlCl/sub 4/)/sub 2/ thionyl chloride/75% Shawinigan - 25% acetone washed Black Pearls 2000 carbon black cathode. The improvement to this cell involves the addition of 10 vol. % bromine to the electrolyte. During discharge at about -30 C, cathode potential is raised by about 0.5 volt providing a cell voltage well above the 2.0 volt minimum which is a standard military specification. Without bromine, cell capacity is about one minute. With the addition of bromine, load voltage is initially 2.5 volts, then slowly decreases to 2.0 volts over about twelve minutes.

  15. Combinatorial electrochemical cell array for high throughput screening of micro-fuel-cells and metal/air batteries

    NASA Astrophysics Data System (ADS)

    Jiang, Rongzhong

    2007-07-01

    An electrochemical cell array was designed that contains a common air electrode and 16 microanodes for high throughput screening of both fuel cells (based on polymer electrolyte membrane) and metal/air batteries (based on liquid electrolyte). Electrode materials can easily be coated on the anodes of the electrochemical cell array and screened by switching a graphite probe from one cell to the others. The electrochemical cell array was used to study direct methanol fuel cells (DMFCs), including high throughput screening of electrode catalysts and determination of optimum operating conditions. For screening of DMFCs, there is about 6% relative standard deviation (percentage of standard deviation versus mean value) for discharge current from 10to20mA/cm2. The electrochemical cell array was also used to study tin/air batteries. The effect of Cu content in the anode electrode on the discharge performance of the tin/air battery was investigated. The relative standard deviations for screening of metal/air battery (based on zinc/air) are 2.4%, 3.6%, and 5.1% for discharge current at 50, 100, and 150mA/cm2, respectively.

  16. Development of a novel electrochemical sensor using pheochromocytoma cells and its assessment of acrylamide cytotoxicity.

    PubMed

    Sun, Xiulan; Ji, Jian; Jiang, Donglei; Li, Xiaowei; Zhang, Yinzhi; Li, Zaijun; Wu, Yongning

    2013-06-15

    We report on a sensitive, simple, label-free cell-based electrochemical sensor to monitor the toxic effect of acrylamide on the Pheochromocytoma cells. The surface of the electrode was modified with gold nanoparticles and electrochemically reduced graphene oxide. Cyclic voltammetry, impedance spectroscopy and differential pulse voltammetry were applied to characterize the modified electrode. Reduced graphene oxide was proved to increase electron-transfer rate between the cell and the surface of electrode, while gold nanoparticle retain cell bioactivity. The sensor exhibited good correlation to the logarithmic value of cell numbers ranging from 1.6×10(4) to 1.6×10(7) cells mL(-1), with R.S.D value of 1.68%. The value of differential pulse voltammetry (cell adsorption concentration of 1.6×10(7) cells mL(-1)) decreased with the concentration of acrylamide in range of 0.1-5 mM with the detection limit as 0.04 mM. Scanning electron microscope-based morphological and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide analysis confirmed the results of the electrochemical study. This sensor was proved to be a useful tool for probing the toxicity of cells, and assisted in the development of a labeling-free, simple, rapid and immediate detection method. PMID:23416312

  17. Quantifying Molecular-Level Cell Adhesion on Electroactive Conducting Polymers using Electrochemical-Single Cell Force Spectroscopy

    PubMed Central

    Zhang, Hongrui; Molino, Paul J.; Wallace, Gordon G.; Higgins, Michael J.

    2015-01-01

    Single Cell Force Spectroscopy was combined with Electrochemical-AFM to quantify the adhesion between live single cells and conducting polymers whilst simultaneously applying a voltage to electrically switch the polymer from oxidized to reduced states. The cell-conducting polymer adhesion represents the non-specific interaction between cell surface glycocalyx molecules and polymer groups such as sulfonate and dodecylbenzene groups, which rearrange their orientation during electrical switching. Single cell adhesion significantly increases as the polymer is switched from an oxidized to fully reduced state, indicating stronger cell binding to sulfonate groups as opposed to hydrophobic groups. This increase in single cell adhesion is concomitant with an increase in surface hydrophilicity and uptake of cell media, driven by cation movement, into the polymer film during electrochemical reduction. Binding forces between the glycocalyx and polymer surface are indicative of molecular-level interactions and during electrical stimulation there is a decrease in both the binding force and stiffness of the adhesive bonds. The study provides insight into the effects of electrochemical switching on cell adhesion at the cell-conducting polymer interface and is more broadly applicable to elucidating the binding of cell adhesion molecules in the presence of electrical fields and directly at electrode interfaces. PMID:26335299

  18. Copper-substituted perovskite compositions for solid oxide fuel cell cathodes and oxygen reduction electrodes in other electrochemical devices

    DOEpatents

    Rieke, Peter C. (Pasco, WA); Coffey, Gregory W. (Richland, WA); Pederson, Larry R. (Kennewick, WA); Marina, Olga A. (Richland, WA); Hardy, John S. (Richland, WA); Singh, Prabhaker (Richland, WA); Thomsen, Edwin C. (Richland, WA)

    2010-07-20

    The present invention provides novel compositions that find advantageous use in making electrodes for electrochemical cells. Also provided are electrochemical devices that include active oxygen reduction electrodes, such as solid oxide fuel cells, sensors, pumps and the like. The compositions comprises a copper-substituted ferrite perovskite material. The invention also provides novel methods for making and using the electrode compositions and solid oxide fuel cells and solid oxide fuel cell assemblies having cathodes comprising the compositions.

  19. Cerium-modified doped strontium titanate compositions for solid oxide fuel cell anodes and electrodes for other electrochemical devices

    DOEpatents

    Marina, Olga A [Richland, WA; Stevenson, Jeffry W [Richland, WA

    2010-03-02

    The present invention provides novel compositions that find advantageous use in making electrodes for electrochemical cells and electrochemical devices such as solid oxide fuel cells, electrolyzers, sensors, pumps and the like, the compositions comprising cerium-modified doped strontium titanate. The invention also provides novel methods for making and using anode material compositions and solid oxide fuel cells and solid oxide fuel cell assemblies having anodes comprising the compositions.

  20. Cerium-modified doped strontium titanate compositions for solid oxide fuel cell anodes and electrodes for other electrochemical devices

    DOEpatents

    Marina, Olga A [Richland, WA; Stevenson, Jeffry W [Richland, WA

    2010-11-23

    The present invention provides novel compositions that find advantageous use in making electrodes for electrochemical cells and electrochemical devices such as solid oxide fuel cells, electrolyzers, sensors, pumps and the like, the compositions comprising cerium-modified doped strontium titanate. The invention also provides novel methods for making and using anode material compositions and solid oxide fuel cells and solid oxide fuel cell assemblies having anodes comprising the compositions.

  1. Free Energies of Formation Measurements on Solid-State Electrochemical Cells

    ERIC Educational Resources Information Center

    Rollino, J. A.; Aronson, S.

    1972-01-01

    A simple experiment is proposed that can provide the student with some insight into the chemical properties of solids. It also demonstrates the relationship between the Gibbs free energy of formation of an ionic solid and the emf of an electrochemical cell. (DF)

  2. Characterization of microbial fuel cells at microbially and electrochemically meaningful time scales.

    PubMed

    Ren, Zhiyong; Yan, Hengjing; Wang, Wei; Mench, Matthew M; Regan, John M

    2011-03-15

    The variable biocatalyst density in a microbial fuel cell (MFC) anode biofilm is a unique feature of MFCs relative to other electrochemical systems, yet performance characterizations of MFCs typically involve analyses at electrochemically relevant time scales that are insufficient to account for these variable biocatalyst effects. This study investigated the electrochemical performance and the development of anode biofilm architecture under different external loadings, with duplicate acetate-fed single-chamber MFCs stabilized at each resistance for microbially relevant time scales. Power density curves from these steady-state reactors generally showed comparable profiles despite the fact that anode biofilm architectures and communities varied considerably, showing that steady-state biofilm differences had little influence on electrochemical performance until the steady-state external loading was much larger than the reactor internal resistance. Filamentous bacteria were dominant on the anodes under high external resistances (1000 and 5000 ?), while more diverse rod-shaped cells formed dense biofilms under lower resistances (10, 50, and 265 ?). Anode charge transfer resistance decreased with decreasing fixed external resistances, but was consistently 2 orders of magnitude higher than the resistance at the cathode. Cell counting showed an inverse exponential correlation between cell numbers and external resistances. This direct link of MFC anode biofilm evolution with external resistance and electricity production offers several operational strategies for system optimization. PMID:21329346

  3. Conceptual Change Text: A Supplementary Material To Facilitate Conceptual Change in Electrochemical Cell Concepts.

    ERIC Educational Resources Information Center

    Yuruk, Nejla; Geban, Omer

    The main purpose of the study was to investigate the effectiveness of conceptual change text (CCT) oriented instruction over traditionally designed instruction on students' understanding of electrochemical (galvanic and electrolytic) cell concepts. The subjects of the study consisted of 64 students from the two classes of a high school in Turkey.…

  4. Electrochemically Deposited Cadmium Electrode for Sealed Ni-cd Cells

    NASA Technical Reports Server (NTRS)

    Houston, W. H.; Edgar, T. A.

    1984-01-01

    An investigation into the work on electrochemical cadmium deposition processes is describred. A beaker impregnation system is constructed to investigate the practical limits of loading and the effect of various process parameters. Reasonably high loadings of cadmium are obtained and the process appears amenable to tight control and the production of uniform consistent electrodes. A pilot impregnation facility is built to further investigate electrodeposition processes. Both the inert anode and consummable anode processes are investigated. Results of this evaluation and an analysis of associated problems are presented.

  5. Sulfur tolerant composite cermet electrodes for solid oxide electrochemical cells

    DOEpatents

    Isenberg, Arnold O. (Pittsburgh, PA)

    1987-01-01

    An electrochemical apparatus is made containing an exterior electrode bonded to the exterior of a tubular, solid, oxygen ion conducting electrolyte where the electrolyte is also in contact with an interior electrode, said exterior electrode comprising particles of an electronic conductor contacting the electrolyte, where a ceramic metal oxide coating partially surrounds the particles and is bonded to the electrolyte, and where a coating of an ionic-electronic conductive material is attached to the ceramic metal oxide coating and to the exposed portions of the particles.

  6. Membrane with internal passages to permit fluid flow and an electrochemical cell containing the same

    NASA Technical Reports Server (NTRS)

    Cisar, Alan J. (Inventor); Gonzalez-Martin, Anuncia (Inventor); Hitchens, G. Duncan (Inventor); Murphy, Oliver J. (Inventor)

    1997-01-01

    The invention provides an improved proton exchange membrane for use in electrochemical cells having internal passages parallel to the membrane surface, an apparatus and process for making the membrane, membrane and electrode assemblies fabricated using the membrane, and the application of the membrane and electrode assemblies to a variety of devices, both electrochemical and otherwise. The passages in the membrane extend from one edge of the membrane to another and allow fluid flow through the membrane and give access directly to the membrane for purposes of hydration.

  7. Method of bonding an interconnection layer on an electrode of an electrochemical cell

    DOEpatents

    Pal, U.B.; Isenberg, A.O.; Folser, G.R.

    1992-01-14

    An electrochemical cell containing an air electrode, contacting electrolyte and electronically conductive interconnection layer, and a fuel electrode, has the interconnection layer attached by: (A) applying a thin, closely packed, discrete layer of LaCrO[sub 3] particles, doped with an element selected from the group consisting of Ca, Sr, Co, Ba, Mg and their mixtures on a portion of the air electrode, and then (B) electrochemical vapor depositing a dense skeletal structure between and around the doped LaCrO[sub 3] particles. 2 figs.

  8. Method of bonding an interconnection layer on an electrode of an electrochemical cell

    DOEpatents

    Pal, Uday B. (Cambridge, MA); Isenberg, Arnold O. (Pittsburgh, PA); Folser, George R. (Lower Burrell, PA)

    1992-01-01

    An electrochemical cell containing an air electrode (16), contacting electrolyte and electronically conductive interconnection layer (26), and a fuel electrode, has the interconnection layer (26) attached by: (A) applying a thin, closely packed, discrete layer of LaCrO.sub.3 particles (30), doped with an element selected from the group consisting of Ca, Sr, Co, Ba, Mg and their mixtures on a portion of the air electrode, and then (B) electrochemical vapor depositing a dense skeletal structure (32) between and around the doped LaCrO.sub.3 particles (30).

  9. Electrochemical cell for obtaining oxygen from carbon dioxide atmospheres

    NASA Technical Reports Server (NTRS)

    Hooker, M. W.; Rast, H. E.; Rogers, D. K.

    1989-01-01

    For manned missions to Mars to become a reality, an efficient and reliable means of obtaining oxygen from the carbon dioxide-rich atmosphere will be required. Otherwise, the high cost of transporting the oxygen needed to sustain the astronauts will severely restrict the expedition to the martian surface. Recently, the use of electrochemical devices has been explored as a means of obtaining oxygen from the carbon dioxide-rich atmosphere. In these devices, oxygen ions diffuse through solid oxide membranes, thus, separating oxygen from the other gases presented. This phenomenon has only recently been explored as a means of obtaining large quantities of oxygen from toxic atmospheres, although first observed by Walter nernst in 1899. Nernst observed that stabilized zirconia will conduct oxygen ions when an electrical potential is applied across metallic electrodes applied to the ceramic membrane. Diatomic oxygen molecules are dissociated at the positive electrode/electrolyte interface. The oxygen ions enter the ceramic body due to the ion density gradient which is produced by the electrical potential across the electrolytic membrane. Once the ions have diffused through the membrane, they reform diatomic oxygen molecules at the anode. The separation of oxygen from carbon dioxide is achieved by the combination of thermal and electrochemical processes. The thermal decomposition of carbon dioxide (at 1000 C) results in the production of carbon monoxide and oxygen by the reaction.

  10. The effect of secondary impurities on solar cell performance

    NASA Technical Reports Server (NTRS)

    Hill, D. E.; Gutsche, H. W.; Wang, M. S.; Gupta, K. P.; Tucker, W. F.; Dowdy, J. D.; Crepin, R. J.

    1976-01-01

    Czochralski and float zone sigle crystals of silicon were doped with the primary impurities B or P so that a resistivity of 0.5 ohm cm resulted, and in addition doped with certain secondary impurities including Al, C, Cr, Cu, Fe, Mg, Mn, Na, Ni, O, Ti, V, and Zr. The actual presence of these impurities was confirmed by analysis of the crystals. Solar cell performance was evaluated and found to be degraded most significantly by Ti, V, and Zr and to some extent by most of the secondary impurities considered. These results are of significance to the low cost silicon program, since any such process would have to yield at least tolerable levels of these impurities.

  11. Electrochemical Reconstitution of Biomolecules for Applications as Electrocatalysts for the Bionanofuel Cell

    NASA Technical Reports Server (NTRS)

    Kim, Jae-Woo; Choi, Sang H.; Lillehei, Peter T.; King, Glen C.; Watt, Gerald D.; Chu, Sang-Hyon; Park, Yeonjoon; Thibeault, Sheila

    2004-01-01

    Platinum-cored ferritins were synthesized as electrocatalysts by electrochemical biomineralization of immobilized apoferritin with platinum. The platinum cored ferritin was fabricated by exposing the immobilized apoferritin to platinum ions at a reduction potential. On the platinum-cored ferritin, oxygen is reduced to water with four protons and four electrons generated from the anode. The ferritin acts as a nano-scale template, a biocompatible cage, and a separator between the nanoparticles. This results in a smaller catalyst loading of the electrodes for fuel cells or other electrochemical devices. In addition, the catalytic activity of the ferritin-stabilized platinum nanoparticles is enhanced by the large surface area and particle size phenomena. The work presented herein details the immobilization of ferritin with various surface modifications, the electrochemical biomineralization of ferritin with different inorganic cores, and the fabrication of self-assembled 2-D arrays with thiolated ferritin.

  12. Fluorescent magnetic bead-based mast cell biosensor for electrochemical detection of allergens in foodstuffs.

    PubMed

    Jiang, Donglei; Zhu, Pei; Jiang, Hui; Ji, Jian; Sun, Xiulan; Gu, Wenshu; Zhang, Genyi

    2015-08-15

    In this study, a novel electrochemical rat basophilic leukemia cell (RBL-2H3) cell sensor, based on fluorescent magnetic beads, has been developed for the detection and evaluation of different allergens in foodstuffs. Fluorescein isothiocyanate (FITC) was successfully fused inside the SiO2 layer of SiO2 shell-coated Fe3O4 nanoparticles, which was superior to the traditional Fe3O4@SiO2@FITC modification process. The as-synthesized fluorescent magnetic beads were then encapsulated with lipidosome to form cationic magnetic fluorescent nanoparticles (CMFNPs) for mast cell magnetofection. The CMFNPs were then characterized by SEM, TEM, VSM, FTIR, and XRD analyses, and transfected into RBL-2H3 cells through a highly efficient, lipid-mediated magnetofection procedure. Magnetic glassy carbon electrode (MGCE), which possesses excellent reproducibility and regeneration qualities, was then employed to adsorb the CMFNP-transfected RBL-2H3 cells activated by an allergen antigen for electrochemical assay. Results show that the exposure of model antigen-dinitrophenol-bovine serum albumin (DNP-BSA) to anti-DNP IgE-sensitized mast cells induced a robust and long-lasting electrochemical impedance signal in a dose-dependent manner. The detection limit was identified at 3.3×10(-4) ng/mL. To demonstrate the utility of this mast cell-based biosensor for detection of real allergens in foodstuffs, Anti-Pen a1 IgE and Anti-PV IgE-activated cells were employed to quantify both shrimp allergen tropomyosin (Pen a 1) and fish allergen parvalbumin (PV). Results show high detection accuracy for these targets, with a limit of 0.03 ?g/mL (shrimp Pen a 1) and 0.16 ng/mL (fish PV), respectively. To this effect, we conclude the proposed method is a facile, highly sensitive, innovative electrochemical method for the evaluation of food allergens. PMID:25889258

  13. Single cells and intracellular processes studied by a plasmonic-based electrochemical impedance microscopy

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Foley, Kyle; Shan, Xiaonan; Wang, Shaopeng; Eaton, Seron; Nagaraj, Vinay J.; Wiktor, Peter; Patel, Urmez; Tao, Nongjian

    2011-03-01

    Electrochemical impedance spectroscopy is a crucial tool for the detection and study of various biological substances, from DNA and proteins to viruses and bacteria. It does not require any labelling species, and methods based on it have been developed to study cellular processes (such as cell spreading, adhesion, invasion, toxicology and mobility). However, data have so far lacked spatial information, which is essential for investigating heterogeneous processes and imaging high-throughput microarrays. Here, we report an electrochemical impedance microscope based on surface plasmon resonance that resolves local impedance with submicrometre spatial resolution. We have used an electrochemical impedance microscope to monitor the dynamics of cellular processes (apoptosis and electroporation of individual cells) with millisecond time resolution. The high spatial and temporal resolution makes it possible to study individual cells, but also resolve subcellular structures and processes without labels, and with excellent detection sensitivity (~2 pS). We also describe a model that simulates cellular and electrochemical impedance microscope images based on local dielectric constant and conductivity.

  14. Assessment of the electrochemical effects of pulsed electric fields in a biological cell suspension.

    PubMed

    Chafai, Djamel Eddine; Mehle, Andraž; Tilmatine, Amar; Maouche, Bachir; Miklav?i?, Damijan

    2015-12-01

    Electroporation of cells is successfully used in biology, biotechnology and medicine. Practical problems still arise in the electroporation of cells in suspension. For example, the determination of cell electroporation is still a demanding and time-consuming task. Electric pulses also cause contamination of the solution by the metal released from the electrodes and create local enhancements of the electric field, leading to the occurrence of electrochemical reactions at the electrode/electrolyte interface. In our study, we investigated the possibility of assessing modifications to the cell environment caused by pulsed electric fields using electrochemical impedance spectroscopy. We designed an experimental protocol to elucidate the mechanism by which a pulsed electric field affects the electrode state in relation to different electrolyte conductivities at the interface. The results show that a pulsed electric field affects electrodes and its degree depends on the electrolyte conductivity. Evolution of the electrochemical reaction rate depends on the initial free charges and those generated by the pulsed electric field. In the presence of biological cells, the initial free charges in the medium are reduced. The electrical current path at low frequency is longer, i.e., conductivity is decreased, even in the presence of increased permeability of the cell membrane created by the pulsed electric field. PMID:26315352

  15. Lichen Secondary Metabolite, Physciosporin, Inhibits Lung Cancer Cell Motility

    PubMed Central

    Yang, Yi; Park, So-Yeon; Nguyen, Thanh Thi; Yu, Young Hyun; Nguyen, Tru Van; Sun, Eun Gene; Udeni, Jayalal; Jeong, Min-Hye; Pereira, Iris; Moon, Cheol; Ha, Hyung-Ho; Kim, Kyung Keun; Hur, Jae-Seoun; Kim, Hangun

    2015-01-01

    Lichens produce various unique chemicals that can be used for pharmaceutical purposes. To screen for novel lichen secondary metabolites showing inhibitory activity against lung cancer cell motility, we tested acetone extracts of 13 lichen samples collected in Chile. Physciosporin, isolated from Pseudocyphellaria coriacea (Hook f. & Taylor) D.J. Galloway & P. James, was identified as an effective compound and showed significant inhibitory activity in migration and invasion assays against human lung cancer cells. Physciosporin treatment reduced both protein and mRNA levels of N-cadherin with concomitant decreases in the levels of epithelial-mesenchymal transition markers such as snail and twist. Physciosporin also suppressed KITENIN (KAI1 C-terminal interacting tetraspanin)-mediated AP-1 activity in both the absence and presence of epidermal growth factor stimulation. Quantitative real-time PCR analysis showed that the expression of the metastasis suppressor gene, KAI1, was increased while that of the metastasis enhancer gene, KITENIN, was dramatically decreased by physciosporin. Particularly, the activity of 3’-untranslated region of KITENIN was decreased by physciosporin. Moreover, Cdc42 and Rac1 activities were decreased by physciosporin. These results demonstrated that the lichen secondary metabolite, physciosporin, inhibits lung cancer cell motility through novel mechanisms of action. PMID:26371759

  16. Method of making an electrolyte for an electrochemical cell

    DOEpatents

    Bates, John B. (Oak Ridge, TN); Dudney, Nancy J. (Knoxville, TN)

    1996-01-01

    Described is a thin-film battery, especially a thin-film microbattery, and a method for making same having application as a backup or primary integrated power source for electronic devices. The battery includes a novel electrolyte which is electrochemically stable and does not react with the lithium anode and a novel vanadium oxide cathode Configured as a microbattery, the battery can be fabricated directly onto a semiconductor chip, onto the semiconductor die or onto any portion of the chip carrier. The battery can be fabricated to any specified size or shape to meet the requirements of a particular application. The battery is fabricated of solid state materials and is capable of operation between -15.degree. C. and 150.degree. C.

  17. Method of making an electrolyte for an electrochemical cell

    DOEpatents

    Bates, J.B.; Dudney, N.J.

    1996-04-30

    Described is a thin-film battery, especially a thin-film microbattery, and a method for making same having application as a backup or primary integrated power source for electronic devices. The battery includes a novel electrolyte which is electrochemically stable and does not react with the lithium anode and a novel vanadium oxide cathode. Configured as a microbattery, the battery can be fabricated directly onto a semiconductor chip, onto the semiconductor die or onto any portion of the chip carrier. The battery can be fabricated to any specified size or shape to meet the requirements of a particular application. The battery is fabricated of solid state materials and is capable of operation between {minus}15 C and 150 C. 9 figs.

  18. Exploratory cell research and fundamental processes study in solid state electrochemical cells

    NASA Astrophysics Data System (ADS)

    Smyrl, William H.; Owens, Boone B.; White, Henry S.

    1990-06-01

    Last year this program demonstrated that some alternatives to lithium had some merit on which to base new polymer electrolyte batteries and other electrochemical devices. We reported that Na, Zn, and Cu electrolytes have modest conductivities at 100 C. Some preliminary cell cycling data were reported with V6 O13 insertion cathodes, and the successful cell cycling suggested that N(sup +), Zn(sup +2) could be inserted and removed reversibly in the cathode material. Also, thin-film polymer cathodes were shown by impedance measurements to have three characteristic regions of behavior. Each region had different controlling processes with relaxation time constants that could be separated with careful manipulation of film thickness, morphology, and charging level. The present report gives results of the continuation of these studies. In particular, the sodium system was studied more intensively with conductivity measurements on sodium triflate in poly(ethyleneoxide)(PEO), and cell studies with V6 O13 and poly(pyrrole)(PPY) cathodes. The impedance work was concluded and several directions of new work in that area were identified. The insertion studies with single crystal V6 O13 were concluded on this program.

  19. Exploratory cell research and fundamental processes study in solid state electrochemical cells

    SciTech Connect

    Smyrl, W.H.; Owens, B.B.; White, H.S. . Dept. of Chemical Engineering and Materials Science)

    1990-06-01

    Last year this program demonstrated that alternative to lithium had some merit on which to base new polymer electrolyte batteries and other electrochemical devices. We reported that Na, Zn, and Cu electrolytes have modest conductivities at 100{degree}C. Some preliminary cell cycling data were reported with V{sub 6}O{sub 13} insertion cathodes, and the successful cell cycling suggested that N{sup +}, Zn{sup +2} could be inserted and removed reversibly in the cathode material. Also, thin-film polymer cathodes were shown by impedance measurements to have three characteristic regions of behavior. Each region had different controlling processes with relaxation time constants that could be separated with careful manipulation of film thickness, morphology, and charging level. The present report gives results of the continuation of these studies. In particular, the sodium system was studied more intensively with conductivity measurements on sodium triflate in poly(ethyleneoxide)(PEO), and cell studies with V{sub 6}O{sub 13} and poly(pyrrole)(PPY) cathodes. The impedance work was concluded and several directions of new work in that area were identified. The insertion studies with single crystal V{sub 6}O{sub 13} were concluded on this program and transferred to NSF funding. 29 refs., 6 figs., 6 tabs.

  20. Paraneoplastic cutaneous lupus secondary to esophageal squamous cell carcinoma

    PubMed Central

    Tworek, Joseph; Schapiro, Brian; Zolotarevsky, Eugene

    2015-01-01

    Sporadic subacute cutaneous lupus erythematosus (SCLE) in an elderly man does not fit a typical demographic for the disease process. Using the McLean’s criteria we were able to establish a temporal relationship between the patient’s diagnosis of esophageal squamous cell carcinoma (SCC) and his dermatosis, both of which responded to cytotoxic chemotherapy. The clinical presentation and progression of the clinical illness is supportive of a very unusual and not previously reported paraneoplastic SCLE secondary to esophageal SCC. PMID:26029469

  1. Origin of photovoltage and photocurrent in the nanoporous dye-sensitized electrochemical solar cell

    SciTech Connect

    Schwarzburg, K.; Willig, F.

    1999-07-15

    The essential role of the dark equilibrium potential is discussed for charge separation and the photovoltaic functioning of the title cell. A quantitative model is presented for the potential distribution in the sponge-type title cell. The unique screening process for the photogenerated electrons is discussed that facilitates their extremely long lifetime since the screening ions cannot function as recombination centers. A general analogy is pointed out for the photovoltaic functioning of the sponge-type electrochemical solar cell and of a conventional single-crystal solid-state solar cell.

  2. Design and Operation of an Electrochemical Methanol Concentration Sensor for Direct Methanol Fuel Cell Systems

    NASA Technical Reports Server (NTRS)

    Narayanan, S. R.; Valdez, T. I.; Chun, W.

    2000-01-01

    The development of a 150-Watt packaged power source based on liquid feed direct methanol fuel cells is being pursued currently at the Jet propulsion Laboratory for defense applications. In our studies we find that the concentration of methanol in the fuel circulation loop affects the electrical performance and efficiency the direct methanol fuel cell systems significantly. The practical operation of direct methanol fuel cell systems, therefore, requires accurate monitoring and control of methanol concentration. The present paper reports on the principle and demonstration of an in-house developed electrochemical sensor suitable for direct methanol fuel cell systems.

  3. Electrochemical cell apparatus having axially distributed entry of a fuel-spent fuel mixture transverse to the cell lengths

    DOEpatents

    Reichner, P.; Dollard, W.J.

    1991-01-08

    An electrochemical apparatus is made having a generator section containing axially elongated electrochemical cells, a fresh gaseous feed fuel inlet, a gaseous feed oxidant inlet, and at least one gaseous spent fuel exit channel, where the spent fuel exit channel passes from the generator chamber to combine with the fresh feed fuel inlet at a mixing apparatus, reformable fuel mixture channel passes through the length of the generator chamber and connects with the mixing apparatus, that channel containing entry ports within the generator chamber, where the axis of the ports is transverse to the fuel electrode surfaces, where a catalytic reforming material is distributed near the reformable fuel mixture entry ports. 2 figures.

  4. Electrochemical characterization of sub-micro-gram amounts of organic semiconductors using scanning droplet cell microscopy

    PubMed Central

    Gasiorowski, Jacek; Mardare, Andrei I.; Sariciftci, Niyazi S.; Hassel, Achim Walter

    2013-01-01

    Scanning droplet cell microscopy (SDCM) uses a very small electrolyte droplet at the tip of a capillary which comes in contact with the working electrode. This method is particularly interesting for studies on organic semiconductors since it provides localized electrochemical investigations with high reproducibility. One clear advantage of applying SDCM is represented by the very small amounts of material necessary (less than 1 mg). Organic materials can be investigated quickly and inexpensively in electrochemical studies with a high throughput. In the present study, thin layers of poly(3-hexylthiophene) (P3HT), which is one of the most often used material for organic solar cells, were deposited on ITO/glass as working electrodes in SDCM studies. The redox reactions in 0.1 M tetra(n-butyl)ammonium hexafluorophosphate (TBAPF6) dissolved in propylene carbonate were studied by cyclic voltammetry and by electrochemical impedance spectroscopy. Two reversible, distinct oxidation steps of the P3HT were detected and their kinetics were studied in detail. The doping of P3HT increased due to the electrochemical oxidation and had resulted in a decrease of the film resistance by a few orders of magnitude. Due to localization on the sample various parameter combinations can be studied quantitatively and reproducibly. PMID:24926226

  5. Response of microfluidic fuel cells to secondary flows

    NASA Astrophysics Data System (ADS)

    Rossi, Massimiliano; Kähler, Christian J.

    2013-11-01

    Microfluidic or membraneless fuel cells (MFCs) are a recent class of miniaturized fuel cells (Ferrigno et al. 2002, Choban et al. 2004) composed by a microchannel in which a parallel laminar stream of two fluids, a fuel and an oxidant, is established. The fuel and oxidant remain in contact but do not mix due to the absence of turbulence. The simple architecture and the fact that no expensive proton exchange membranes are needed make this configuration technologically very attractive, however the efficiency especially in terms of fuel utilization is still too low to be competitive for practical applications. One limitation is given by the formation of depletion boundary layers at the electrodes that worsen the red-ox reactions. A way to reduce this problem is to use transversal secondary flows to stir the fluid streams and replenish the depletion layers. In this study, we intend to characterize the performance of MFC with curved channels in which the transversal secondary flows are present in the form of two counter-rotating vortices known as Dean vortices. The characterization will be completed by simultaneous measurements of the current intensity and of the flow velocity performed with 3D Astigmatic Particle Tracking Velocimetry.

  6. Transfected single-cell imaging by scanning electrochemical optical microscopy with shear force feedback regulation.

    PubMed

    Takahashi, Yasufumi; Shiku, Hitoshi; Murata, Tatsuya; Yasukawa, Tomoyuki; Matsue, Tomokazu

    2009-12-01

    Gene-transfected single HeLa cells were characterized using a scanning electrochemical/optical microscope (SECM/OM) system with shear-force-based probe-sample distance regulation to simultaneously capture electrochemical, fluorescent, and topographic images. The outer and inner states of single living cells were obtained as electrochemical and fluorescent signals, respectively, by using an optical fiber-nanoelectrode probe. A focused ion beam (FIB) was used to mill the optical aperture and the ring electrode at the probe apex (the inner and outer radii of the ring electrode were 37 and 112 nm, respectively). To apply an appropriate shear force between the probe tip and the living cell surface, we optimized the amplitude of oscillation of the tuning fork to which the probe was attached. Field-programmable gate arrays (FPGA) were adopted to drastically increase the feedback speed of the tip-sample distance regulation, shorten the scanning time for imaging, and enhance the accuracy and quality of the living cell images. In employing these improvements, we simultaneously measured the cellular expression activity of both secreted alkaline phosphatase outside and GFP inside by using the SECM/OM with shear force distance regulation. PMID:19883061

  7. Life testing of secondary silver-zinc cells

    NASA Technical Reports Server (NTRS)

    Brewer, Jeffrey C.; Doreswamy, Rajiv

    1991-01-01

    Testing on a variety of secondary silver-zinc (Ag-Zn) cells has been in progress at the Marshall Space Flight Center (MSFC) for over six years. The latest test involves a 350-Ah cell design that has been cycled at 10 C for 16 months. This design has achieved over 7200 low-earth-orbit (LEO) cycles as well as 17 deep discharges at an 85 percent depth of discharge. This test not only is a life test on these cells but also addresses different methods of storing these cells between the deep discharges. As the test is approaching completion, some interesting results are being seen. In particular, two of the four packs currently on test have failed to meet the 35-h (295-Ah) deep discharge requirement that was arbitrarily set at the beginning of the test. This capacity loss failure is likely a result of the storage method used on these two packs between deep discharges. The two packs are LEO cycled in such a way as to minimize overcharge in an attempt to prolong life.

  8. Cellulose-hemicellulose interaction in wood secondary cell-wall

    NASA Astrophysics Data System (ADS)

    Zhang, Ning; Li, Shi; Xiong, Liming; Hong, Yu; Chen, Youping

    2015-12-01

    The wood cell wall features a tough and relatively rigid fiber reinforced composite structure. It acts as a pressure vessel, offering protection against mechanical stress. Cellulose microfibrils, hemicellulose and amorphous lignin are the three major components of wood. The structure of secondary cell wall could be imagined as the same as reinforced concrete, in which cellulose microfibrils acts as reinforcing steel bar and hemicellulose-lignin matrices act as the concrete. Therefore, the interface between cellulose and hemicellulose/lignin plays a significant role in determine the mechanical behavior of wood secondary cell wall. To this end, we present a molecular dynamics (MD) simulation study attempting to quantify the strength of the interface between cellulose microfibrils and hemicellulose. Since hemicellulose binds with adjacent cellulose microfibrils in various patterns, the atomistic models of hemicellulose-cellulose composites with three typical binding modes, i.e. bridge, loop and random binding modes are constructed. The effect of the shape of hemicellulose chain on the strength of hemicellulose-cellulose composites under shear loadings is investigated. The contact area as well as hydrogen bonds between cellulose and hemicellulose, together with the covalent bonds in backbone of hemicellulose chain are found to be the controlling parameters which determine the strength of the interfaces in the composite system. For the bridge binding model, the effect of shear loading direction on the strength of the cellulose material is also studied. The obtained results suggest that the shear strength of wood-inspired engineering composites can be optimized through maximizing the formations of the contributing hydrogen bonds between cellulose and hemicellulose.

  9. Electronic circuit for measuring series connected electrochemical cell voltages

    DOEpatents

    Ashtiani, Cyrus N. (West Bloomfield, MI); Stuart, Thomas A. (Toledo, OH)

    2000-01-01

    An electronic circuit for measuring voltage signals in an energy storage device is disclosed. The electronic circuit includes a plurality of energy storage cells forming the energy storage device. A voltage divider circuit is connected to at least one of the energy storage cells. A current regulating circuit is provided for regulating the current through the voltage divider circuit. A voltage measurement node is associated with the voltage divider circuit for producing a voltage signal which is proportional to the voltage across the energy storage cell.

  10. Characterization of PEM fuel cell membrane-electrode-assemblies by electrochemical methods and microanalysis

    SciTech Connect

    Borup, R.L.; Vanderborgh, N.E.

    1995-09-01

    Characterization of Membrane Electrode Assemblies (MEAs) is used to help optimize construction of the MEA. Characterization techniques include electron microscopies (SEM and TEM), and electrochemical evaluation of the catalyst. Electrochemical hydrogen adsorption/desorption (HAD) and CO oxidation are used to evaluate the active Pt surface area of fuel cell membrane electrode assemblies. Electrochemical surface area measurements have observed large active Pt surface areas, on the order of 50 m{sup 2}/g for 20% weight Pt supported on graphite. Comparison of the hydrogen adsorption/desorption with CO oxidation indicates that on the supported catalysts, the saturation coverage of CO/Pt is about 0.90, the same as observed in H{sub 2}SO{sub 4}. The catalyst surface area measurements are nearly a factor of 2 lower than the Pt surface area calculated from the 30 {angstrom} average particle size observed by TEM. The electrochemical measurements combined with microanalysis of membrane electrode assemblies, allow a greater understanding and optimization of process variables.

  11. Potassium Beta-Alumina/Molybdenum/Potassium Electrochemical Cells

    NASA Technical Reports Server (NTRS)

    Williams, R.; Kisor, A.; Ryan, M.; Nakamura, B.; Kikert, S.; O'Connor, D.

    1994-01-01

    potassium alkali metal thermal-to-electric converter (K-AMTEC) cells utilizing potassium beta alumina solid electrolyte (K-BASE) are predicted to have improved properties for thermal to electric conversion at somewhat lower temperatures than sodium AMTEC's.

  12. Sources of background current in the ECC ozonesonde - Implications for total ozone measurements. [Electrochemical Concentration Cell

    NASA Technical Reports Server (NTRS)

    Thornton, D. C.; Niazy, N.

    1982-01-01

    The source of the background current in the usual operation of the electrochemical concentration cell ozonesonde is the reduction of tri-iodide normally present in the cathode solution. The time variations in the background current can be explained by the slow rates of solution mass transport and of heterogeneous electron transfer for tri-iodide. Oxygen does not contribute to the background current through reaction with iodide to produce tri-iodide. Direct reduction of oxygen at the cathode is negligible once the electrodes have been exposed to iodide for 24 hours. The present background current correction is altitude-dependent, since it is based on an assumed sensitivity of the electrochemical concentration cell to oxygen. If the background current is independent of altitude and of oxygen, a constant, uncorrected, background current of 0.1 microamp would produce an error of +5.5% for the total ozone value of the electrochemical concentration cell for a typical midlatitude total ozone value of 0.345 atm-cm.

  13. Numerical Study of the Buoyancy-Driven Flow in a Four-Electrode Rectangular Electrochemical Cell

    NASA Astrophysics Data System (ADS)

    Sun, Zhanyu; Agafonov, Vadim; Rice, Catherine; Bindler, Jacob

    2009-11-01

    Two-dimensional numerical simulation is done on the buoyancy-driven flow in a four-electrode rectangular electrochemical cell. Two kinds of electrode layouts, the anode-cathode-cathode-anode (ACCA) and the cathode-anode-anode-cathode (CAAC) layouts, are studied. In the ACCA layout, the two anodes are placed close to the channel outlets while the two cathodes are located between the two anodes. The CAAC layout can be converted from the ACCA layout by applying higher electric potential on the two middle electrodes. Density gradient was generated by the electrodic reaction I3^-+2e^- =3I^-. When the electrochemical cell is accelerated axially, buoyancy-driven flow occurs. In our model, electro-neutrality is assumed except at the electrodes. The Navier-Stokes equations with the Boussinesq approximation and the Nernst-Planck equations are employed to model the momentum and mass transports, respectively. It is found that under a given axial acceleration, the electrolyte density between the two middle electrodes determines the bulk flow through the electrochemical cell. The cathodic current difference is found to be able to measure the applied acceleration. Other important electro-hydrodynamic characteristics are also discussed.

  14. Electrochemical K-562 cells sensor based on origami paper device for point-of-care testing.

    PubMed

    Ge, Shenguang; Zhang, Lina; Zhang, Yan; Liu, Haiyun; Huang, Jiadong; Yan, Mei; Yu, Jinghua

    2015-12-01

    A low-cost, simple, portable and sensitive paper-based electrochemical sensor was established for the detection of K-562 cell in point-of-care testing. The hybrid material of 3D Au nanoparticles/graphene (3D Au NPs/GN) with high specific surface area and ionic liquid (IL) with widened electrochemical windows improved the good biocompatibility and high conductivity was modified on paper working electrode (PWE) by the classic assembly method and then employed as the sensing surface. IL could not only enhance the electron transfer ability but also provide sensing recognition interface for the conjugation of Con A with cells, with the cell capture efficiency and the sensitivity of biosensor strengthened simultaneously. Concanavalin A (Con A) immobilization matrix was used to capture cells. As proof-of-concept, the paper-based electrochemical sensor for the detection of K-562 cells was developed. With such sandwich-type assay format, K-562 cells as model cells were captured on the surface of Con A/IL/3D AuNPs@GN/PWE. Con A-labeled dendritic PdAg NPs were captured on the surface of K-562 cells. Such dendritic PdAg NPs worked as catalysts promoting the oxidation of thionine (TH) by H2O2 which was released from K-562 cells via the stimulation of phorbol 12-myristate-13-acetate (PMA). Therefore, the current signal response was dependent on the amount of PdAg NPs and the concentration of H2O2, the latter of which corresponded with the releasing amount from cells. So, the detection method of K-562 cell was also developed. Under optimized experimental conditions, 1.5×10(-14)mol of H2O2 releasing from each cell was calculated. The linear range and the detection limit for K-562 cells were determined to be 1.0×10(3)-5.0×10(6)cells/mL and 200cells/mL, respectively. Such as-prepared sensor showed excellent analytical performance with good fabrication reproducibility, acceptable precision and satisfied accuracy, providing a novel protocol in point-of-care testing of cells. PMID:26459438

  15. CELLULOSE SYNTHASE9 Serves a Nonredundant Role in Secondary Cell Wall Synthesis in Arabidopsis

    E-print Network

    Haughn, George

    CELLULOSE SYNTHASE9 Serves a Nonredundant Role in Secondary Cell Wall Synthesis in Arabidopsis micrographs and quantitatively showed depletion of secondary cell wall synthesis in the radial cell wall the dehydrated dormant state of the embryo until appropriate conditions exist (Windsor et al., 2000). A good

  16. Further observations on the phenomenon of secondary vacuolation in living cells.

    NASA Technical Reports Server (NTRS)

    Mahlberg, P.

    1972-01-01

    The dynamics of secondary vacuole movement is studied in living hair cells of Tradescantia virginiana. The pattern of movement of these vacuoles is found to be similar to that described by the author previously for organelles in cultured cells. Evidence is presented in support of the thesis that the occurrence and dynamics of secondary vacuoles is a common phenomenon for plant cells.

  17. Assessment of multidrug resistance on cell coculture patterns using scanning electrochemical microscopy

    PubMed Central

    Kuss, Sabine; Polcari, David; Geissler, Matthias; Brassard, Daniel; Mauzeroll, Janine

    2013-01-01

    The emergence of resistance to multiple unrelated chemotherapeutic drugs impedes the treatment of several cancers. Although the involvement of ATP-binding cassette transporters has long been known, there is no in situ method capable of tracking this transporter-related resistance at the single-cell level without interfering with the cell’s environment or metabolism. Here, we demonstrate that scanning electrochemical microscopy (SECM) can quantitatively and noninvasively track multidrug resistance-related protein 1–dependent multidrug resistance in patterned adenocarcinoma cervical cancer cells. Nonresistant human cancer cells and their multidrug resistant variants are arranged in a side-by-side format using a stencil-based patterning scheme, allowing for precise positioning of target cells underneath the SECM sensor. SECM measurements of the patterned cells, performed with ferrocenemethanol and [Ru(NH3)6]3+ serving as electrochemical indicators, are used to establish a kinetic “map” of constant-height SECM scans, free of topography contributions. The concept underlying the work described herein may help evaluate the effectiveness of treatment administration strategies targeting reduced drug efflux. PMID:23686580

  18. Effects of composition on the electrochemical property and cell performance of single layer fuel cell

    NASA Astrophysics Data System (ADS)

    Hu, Huiqing; Lin, Qizhao; Zhu, Zhigang; Liu, Xiangrong; Afzal, Muhammad; He, Yunjuan; Zhu, Bin

    2015-02-01

    In this study, the enhanced electrochemical performance of single layer fuel cells (SLFCs) based upon mixed ion and electron conductors is analyzed as a function of composition. We synthesize a series of Ce0.8Sm0.2O2-?-Li0.3Ni0.6Cu0.07Sr0.03O2-? (SDC-LNCS) with different weight ratios. The microstructure and morphology of the composite materials are characterized through X-ray diffraction (XRD), transmission electron microscope (TEM), and energy-dispersive X-ray spectrometer (EDS). Stability of the synthesized samples is evaluated by thermal gravity analysis (TGA). The SLFC with 6SDC-4LNCS exhibits a uniform distribution of the two compositions as well as demonstrates the highest power density of 312 mW cm-2 at 550 °C. The performance is correlated to the balance of the conduction properties (ionic and electronic) of the functional SLFC layer. The results are a critical contribution to further development of this new energy transfer device.

  19. Fabrication of VB2/Air Cells for Electrochemical Testing

    PubMed Central

    Stuart, Jessica; Lopez, Ruben; Lau, Jason; Li, Xuguang; Waje, Mahesh; Mullings, Matthew; Rhodes, Christopher; Licht, Stuart

    2013-01-01

    A technique to investigate the properties and performance of new multi-electron metal/air battery systems is proposed and presented. A method for synthesizing nanoscopic VB2 is presented as well as step-by-step procedure for applying a zirconium oxide coating to the VB2 particles for stabilization upon discharge. The process for disassembling existing zinc/air cells is shown, in addition construction of the new working electrode to replace the conventional zinc/air cell anode with a the nanoscopic VB2 anode. Finally, discharge of the completed VB2/air battery is reported. We show that using the zinc/air cell as a test bed is useful to provide a consistent configuration to study the performance of the high-energy high capacity nanoscopic VB2 anode. PMID:23962835

  20. Process for manufacturing a lithium alloy electrochemical cell

    DOEpatents

    Bennett, William R. (North Olmstead, OH)

    1992-10-13

    A process for manufacturing a lithium alloy, metal sulfide cell tape casts slurried alloy powders in an organic solvent containing a dissolved thermoplastic organic binder onto casting surfaces. The organic solvent is then evaporated to produce a flexible tape removable adhering to the casting surface. The tape is densified to increase its green strength and then peeled from the casting surface. The tape is laminated with a separator containing a lithium salt electrolyte and a metal sulfide electrode to form a green cell. The binder is evaporated from the green cell at a temperature lower than the melting temperature of the lithium salt electrolyte. Lithium alloy, metal sulfide and separator powders may be tape cast.

  1. Thin-film electrochemical power cells. Final report

    SciTech Connect

    Owens, B.B.; Smyrl, W.H.

    1991-01-01

    Fundamental properties of research cells were correlated with the projected performance of full scale power sources, considering both battery and supercapacitor concepts. In addition to establishing the data base for modelling and performance projections, the program had the additional objective of identifying loss mechanisms and degradation reactions, especially those unique to polymer thin film cell designs. Because of the intrinsic high electrode/electrolyte interface areas, interfacial reactions must be understood. Many applications require power under extreme conditions, and low temperature performance needs to be improved.

  2. Direct In Vivo Electrochemical Detection of Haemoglobin in Red Blood Cells

    NASA Astrophysics Data System (ADS)

    Toh, Rou Jun; Peng, Weng Kung; Han, Jongyoon; Pumera, Martin

    2014-08-01

    The electrochemical behavior of iron ion in haemoglobin provides insight to the chemical activity in the red blood cell which is important in the field of hematology. Herein, the detection of haemoglobin in human red blood cells on glassy carbon electrode (GC) was demonstrated. Red blood cells or raw blood cells was immobilized on a glassy carbon electrode surface with Nafion films employed to sandwich the layer of biological sample firmly on the electrode surface. Cyclic voltammetry (CV) analyses revealed a well-defined reduction peak for haemoglobin at about -0.30 V (vs. Ag/AgCl) at the red blood cell (GC-Nf-RBC-3Nf) and blood (GC-Nf-B-3Nf) film modified GCE in a pH 3.5 phosphate buffer solution. We further demonstrated that the complex biological conditions of a human red blood cell displayed no interference with the detection of haemoglobin. Such findings shall have an implication on the possibilities of studying the electrochemical behaviour of haemoglobin directly from human blood, for various scientific and clinical purposes.

  3. In situ label-free quantification of human pluripotent stem cells with electrochemical potential.

    PubMed

    Yea, Cheol-Heon; Jeong, Ho-Chang; Moon, Sung-Hwan; Lee, Mi-Ok; Kim, Kyeong-Jun; Choi, Jeong-Woo; Cha, Hyuk-Jin

    2016-01-01

    Conventional methods for quantification of undifferentiated pluripotent stem cells such as fluorescence-activated cell sorting and real-time PCR analysis have technical limitations in terms of their sensitivity and recyclability. Herein, we designed a real-time in situ label-free monitoring system on the basis of a specific electrochemical signature of human pluripotent stem cells in vitro. The intensity of the signal of hPSCs highly corresponded to the cell number and remained consistent in a mixed population with differentiated cells. The electrical charge used for monitoring did not markedly affect the proliferation rate or molecular characteristics of differentiated human aortic smooth muscle cells. After YM155 treatment to ablate undifferentiated hPSCs, their specific signal was significantly reduced. This suggests that detection of the specific electrochemical signature of hPSCs would be a valid approach to monitor potential contamination of undifferentiated hPSCs, which can assess the risk of teratoma formation efficiently and economically. PMID:26513417

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

    E-print Network

    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

  5. Time-course correlation of biofilm properties and electrochemical performance in single-chamber microbial fuel cells

    E-print Network

    Mench, Matthew M.

    -chamber microbial fuel cells Zhiyong Ren a,c , Ramaraja P. Ramasamy b,1 , Susan Red Cloud-Owen b , Hengjing Yan 2010 Keywords: Microbial fuel cell Electricity Biofilm Electrochemical impedance spectroscopy a b s t r in microbial fuel cells (MFCs) was analyzed by time-course sampling of parallel single-bottle MFCs operated

  6. Parenchyma cell respiration and survival in secondary xylem: does metabolic activity decline with cell age?

    E-print Network

    Holbrook, N. Michele

    Parenchyma cell respiration and survival in secondary xylem: does metabolic activity decline Divinity Avenue, Cambridge, MA 02138, USA ABSTRACT Sapwood respiration often declines towards the sapwood sapwood respiration in five temperate species (sapwood age range of 5­64 years) and expressed respiration

  7. Indium tin oxide based chip for optical and electrochemical characterization of protein-cell interaction

    NASA Astrophysics Data System (ADS)

    Choi, Yong Hyun; Min, Junhong; Cho, Sungbo

    2015-06-01

    Analysis on the interaction between proteins and cells is required for understanding the cellular behaviour and response. In this article, we characterized the adhesion and growth of 293/GFP cells on fetal bovine serum (FBS) coated indium tin oxide (ITO) electrode. Using optical and electrochemical measurement, it was able to detect the adsorption of the protein on the surface of the ITO electrode dependent on the concentration of the protein in the immersing solution or the immersing time. An increase in the amount of the adsorbed serum protein resulted in a decrease in anodic peak current and an increase in the charge transfer resistance extracted from the equivalent circuit fitting analysis. More cells adhered and proliferated on the ITO electrode which was pre-immersed in FBS medium rather than bare electrode. The effect of the FBS on cell behaviors was reflected in the impedance monitoring of cells at 21.5 kHz.

  8. Electrochemical cell apparatus having an integrated reformer-mixer nozzle-mixer diffuser

    DOEpatents

    Shockling, Larry A. (Plum Borough, PA)

    1991-01-01

    An electrochemical apparatus (10) is made having a generator section (22) containing electrochemical cells (16), a fresh gaseous feed fuel inlet (28), a gaseous feed oxidant inlet (30), and at least one hot gaseous spent fuel recirculation channel (46), where the spent fuel recirculation channel (46), passes from the generator chamber (22) to combine with the fresh feed fuel inlet (28) to form a reformable mixture, where a reforming chamber (54) contains an outer portion containing reforming material (56), an inner portion preferably containing a mixer nozzle (50) and a mixer-diffuser (52), and a middle portion (64) for receiving spent fuel, where the mixer nozzle (50) and mixer-diffuser (52) are preferably both within the reforming chamber (54) and substantially exterior to the main portion of the apparatus, where the reformable mixture flows up and then backward before contacting the reforming material (56), and the mixer nozzle (50) can operate below 400.degree. C.

  9. Electrochemical cell apparatus having an integrated reformer-mixer nozzle-mixer diffuser

    DOEpatents

    Shockling, L.A.

    1991-09-10

    An electrochemical apparatus is made having a generator section containing electrochemical cells, a fresh gaseous feed fuel inlet, a gaseous feed oxidant inlet, and at least one hot gaseous spent fuel recirculation channel, where the spent fuel recirculation channel, passes from the generator chamber to combine with the fresh feed fuel inlet to form a reformable mixture, where a reforming chamber contains an outer portion containing reforming material, an inner portion preferably containing a mixer nozzle and a mixer-diffuser, and a middle portion for receiving spent fuel, where the mixer nozzle and mixer-diffuser are preferably both within the reforming chamber and substantially exterior to the main portion of the apparatus, where the reformable mixture flows up and then backward before contacting the reforming material, and the mixer nozzle can operate below 400 C. 1 figure.

  10. Space Electrochemical Research and Technology

    NASA Technical Reports Server (NTRS)

    1993-01-01

    This document contains the proceedings of NASA's fourth Space Electrochemical Research and Technology (SERT) Conference, held at the NASA Lewis Research Center on April 14-15, 1993. The objective of the conference was to assess the present status and general thrust of research and development in those areas of electrochemical technology required to enable NASA missions into the next century. The conference provided a forum for the exchange of ideas and opinions of those actively involved in the field, in order to define new opportunities for the application of electrochemical processes in future NASA missions. Papers were presented in three technical areas: advanced secondary batteries, fuel cells, and advanced concepts for space power. This document contains the papers presented.

  11. Fabrication of homojunction Cu2O solar cells by electrochemical deposition

    NASA Astrophysics Data System (ADS)

    Hsu, Yu-Kuei; Wu, Jan-Rung; Chen, Mei-Hsin; Chen, Ying-Chu; Lin, Yan-Gu

    2015-11-01

    Homostructural Cu2O solar cells were fabricated with consecutive electrochemical depositions of a p-Cu2O thin film and a n-Cu2O layer on a transparent conductive substrate. The parameters of growth Coulomb number for n-type and p-type Cu2O films, which determine the film thickness of Cu2O, were fine-tuned to investigate their effects on the performance of homojunction solar cells. According to XRD and SEM analyses, the crystalline structure and the optimum thickness of Cu2O films were accomplished at growth Coulomb numbers 0.135 C for n-Cu2O and 0.208 C for p-Cu2O. Significantly, the best performance of the homojunction Cu2O cell achieved conversion efficiency 0.42% with Voc = 0.42 V, Jsc = 2.68 mA cm-2 and FF = 0.38. This work hence demonstrates that the proposed strategy to improve the performance of solar cells realized by electrochemical deposition has the potential to produce cheap and environmental friendly solar cells.

  12. New double-band-electrode channel flow differential electrochemical mass spectrometry cell: application for detecting product formation during methanol electrooxidation.

    PubMed

    Wang, Hongsen; Rus, Eric; Abruña, Héctor D

    2010-06-01

    We present a new double-band-electrode channel flow DEMS (differential electrochemical mass spectrometry) cell and demonstrate its application in mechanistic studies with particular relevance to fuel cells. The cell is composed of two band electrodes, which serve as working and detecting electrodes, respectively, separated by a porous Teflon membrane. The Teflon membrane serves as the interface between the aqueous solution and vacuum, through which gases and volatile species can be transported. The hydrodynamic electrochemical characteristics and mass spectrometric behavior have been characterized. With this DEMS cell, gaseous and volatile electrochemical products formed at the working electrode are monitored by mass spectrometry, while nonvolatile products can be selectively detected at the detecting (downstream) electrode. Thus, this system can be considered as the DEMS analogue of a rotating ring/disk electrode. As test cases, the electrooxidation of formaldehyde and methanol on carbon supported Pt nanoparticle catalysts have been studied using this new channel flow DEMS cell. PMID:20459058

  13. An optically transparent thin-layer electrochemical cell for the study of vibrational circular dichroism of chiral redox-active molecules

    NASA Astrophysics Data System (ADS)

    Domingos, Sérgio R.; Luyten, Henk; van Anrooij, Fred; Sanders, Hans J.; Bakker, Bert H.; Buma, Wybren J.; Hartl, František; Woutersen, Sander

    2013-03-01

    An optically transparent thin-layer electrochemical (OTTLE) cell with a locally extended optical path has been developed in order to perform vibrational circular dichroism (VCD) spectroscopy on chiral molecules prepared in specific oxidation states by means of electrochemical reduction or oxidation. The new design of the electrochemical cell successfully addresses the technical challenges involved in achieving sufficient infrared absorption. The VCD-OTTLE cell proves to be a valuable tool for the investigation of chiral redox-active molecules.

  14. Microfluidic electrochemical reactors

    DOEpatents

    Nuzzo, Ralph G. (Champaign, IL); Mitrovski, Svetlana M. (Urbana, IL)

    2011-03-22

    A microfluidic electrochemical reactor includes an electrode and one or more microfluidic channels on the electrode, where the microfluidic channels are covered with a membrane containing a gas permeable polymer. The distance between the electrode and the membrane is less than 500 micrometers. The microfluidic electrochemical reactor can provide for increased reaction rates in electrochemical reactions using a gaseous reactant, as compared to conventional electrochemical cells. Microfluidic electrochemical reactors can be incorporated into devices for applications such as fuel cells, electrochemical analysis, microfluidic actuation, pH gradient formation.

  15. Mixed solvent electrolytes for ambient temperature secondary lithium cells

    NASA Technical Reports Server (NTRS)

    Shen, David H. (Inventor); Surampudi, Subbarao (Inventor); Deligiannis, Fotios (Inventor); Halpert, Gerald (Inventor)

    1991-01-01

    The present invention comprises an improved electrolyte for secondary lithium-based cells as well as batteries fabricated using this electrolyte. The electrolyte is a lithium containing salt dissolved in a non-aqueous solvent, which is made from a mixture of ethylene carbonate, ethylene propylene diene terpolymer, 2-methylfuran, and 2-methyltetrahydrofuran. This improved, mixed solvent electrolyte is more conductive than prior electrolytes and much less corrosive to lithium anodes. Batteries constructed with this improved electrolyte utilize lithium or lithium alloy anodes and cathodes made of metal chalcogenides or oxides, such as TiS.sub.2, NbSe.sub.3, V.sub.6 O.sub.13, V.sub.2 O.sub.5, MoS.sub.2, MoS.sub.3, CoO.sub.2, or CrO.sub.2, dissolved in a supporting polymer matrix, like EPDM. The preferred non-aqueous solvent mixture comprises approximately 5 to 30 volume percent ethylene carbonate, approximately 0.01 to 0.1 weight percent ethylene propylene diene terpolymer, and approximately 0.2 to 2 percent 2-methylfuran, with the balance being 2-methyltetrahydrofuran. The most preferred solvent comprises approximately 10 to 20 volume percent ethylene carbonate, about 0.05 weight percent ethylene propylene diene terpolymer, and about 1.0 percent 2-methylfuran, with the balance being 2-methyltetrahydrofuran. The concentration of lithium arsenic hexafluoride can range from about 1.0 to 1.8 M; a concentration 1.5 M is most preferred. Secondary batteries made with the improved electrolyte of this invention have lower internal impedance, longer cycle life, higher energy density, low self-discharge, and longer shelf life.

  16. 3D CFD ELECTROCHEMICAL AND HEAT TRANSFER MODEL OF AN INTERNALLY MANIFOLDED SOLID OXIDE ELECTROLYSIS CELL

    SciTech Connect

    Grant L. Hawkes; James E. O'Brien; Greg Tao

    2011-11-01

    A three-dimensional computational fluid dynamics (CFD) electrochemical model has been created to model high-temperature electrolysis cell performance and steam electrolysis in an internally manifolded planar solid oxide electrolysis cell (SOEC) stack. This design is being evaluated at the Idaho National Laboratory for hydrogen production from nuclear power and process heat. Mass, momentum, energy, and species conservation and transport are provided via the core features of the commercial CFD code FLUENT. A solid-oxide fuel cell (SOFC) model adds the electrochemical reactions and loss mechanisms and computation of the electric field throughout the cell. The FLUENT SOFC user-defined subroutine was modified for this work to allow for operation in the SOEC mode. Model results provide detailed profiles of temperature, operating potential, steam-electrode gas composition, oxygen-electrode gas composition, current density and hydrogen production over a range of stack operating conditions. Single-cell and five-cell results will be presented. Flow distribution through both models is discussed. Flow enters from the bottom, distributes through the inlet plenum, flows across the cells, gathers in the outlet plenum and flows downward making an upside-down ''U'' shaped flow pattern. Flow and concentration variations exist downstream of the inlet holes. Predicted mean outlet hydrogen and steam concentrations vary linearly with current density, as expected. Effects of variations in operating temperature, gas flow rate, oxygen-electrode and steam-electrode current density, and contact resistance from the base case are presented. Contour plots of local electrolyte temperature, current density, and Nernst potential indicate the effects of heat transfer, reaction cooling/heating, and change in local gas composition. Results are discussed for using this design in the electrolysis mode. Discussion of thermal neutral voltage, enthalpy of reaction, hydrogen production, cell thermal efficiency, cell electrical efficiency, and Gibbs free energy are discussed and reported herein.

  17. Teaching Cell Division to Secondary School Students: An Investigation of Difficulties Experienced by Turkish Teachers

    ERIC Educational Resources Information Center

    Oztap, Haydar; Ozay, Esra; Oztap, Fulya

    2003-01-01

    This study examines the difficulties biology teachers face when teaching cell division in the secondary schools of the central part of the Erzurum province in Turkey. During this research, a questionnaire was distributed to a total of 36 secondary school biology teachers. Findings of the study indicate biology teachers perceive cell division as…

  18. Electrochemical Thermal Network Model for Multi-Cell Lithium Ion Battery

    Energy Science and Technology Software Center (ESTSC)

    2009-02-28

    Increasing the numbers and size of cells in a battery pack complicates electrical and thermal control of the system. In addition to keeping a battery pack in the optimal temperature range, maintaining temperature uniformity among all cells in a pack is important to prolong life and enhance safety. Electrical, electrochemical, and thermal responses of a lithium ion battery are closely coupled through macroscopic design factors of the cells and module or pack. The model hasmore »to resolve complex interaction between cell characteristics, pack design, and load conditions. Safe and durable battery pack design requires a battery thermal model that can be coupled with a battery performance more and/or safety model with good accuracy and simulation time. The model is proposed to be used for various technical purposes: Design optimization for safety and/or performance, On-board control.« less

  19. Test report for measurement of performance vs temperature of Whittaker Electrochemical Cell

    SciTech Connect

    Vargo, G.F., Fluor Daniel Hanford

    1997-02-13

    This document is the test report that summarizes the results of the tests on the Whittaker cells between the temperatures of -20{degrees}F and +120{degrees}F. These sensors are used on the Rotary Mode Core Sampling (RMCS) flammable gas interlock (FGI), to detect and quantify hydrogen gas. The test consisted of operating five Whittaker electrochemical cells in an environmental chamber that was varied in temperature from -20{degrees}F to +120{degrees}F. As the rate rise of the voltage from the cells changed, after exposure to a gas concentration of 1% hydrogen at the different temperatures, the voltage was recorded on a computer controlled data acquisition system. Analysis of the data was made to determine if the cells maximum output voltages and rise times were effected by temperature.

  20. Lithium Ion Secondary Cell Prepared by a Printing Procedure, and Its Application to All-Solid-State Inorganic Lithium Ion Cells

    NASA Astrophysics Data System (ADS)

    Mori, Ryohei

    2014-04-01

    We have developed a straightforward printing method for preparation of a lithium secondary cell. LiCo1/3Ni1/3Mn1/3O2 and Li4Ti5O12 viscous printable pastes were used for the cathode and anode, respectively. Electrochemical measurement was used to characterize the capacitance of each cell, and field-emission scanning electron microscopy and particle size measurements were used to characterize particle size and morphology. These film electrodes functioned stably both in a standard liquid electrolyte and in an Li2SiO3 solid electrolyte, although the capacitance of the all-solid-state cell was significantly lower than that of the cell containing liquid electrolyte. When liquid electrolyte was used, the capacity decreased by 36% after 50 cycles. However, the capacity of 0.2 mA h/g remained almost the same even after 50 charge-discharge cycles, demonstrating the stability and strength of the all-solid-state lithium ion cell. It was also found that the cell resistance mostly arose from the electrode/electrolyte interface and not from the bulk electrolyte. Addition of a sol-gel to the solid electrolyte printable paste improved cell performance.

  1. Electrochemical Detection of Circadian Redox Rhythm in Cyanobacterial Cells via Extracellular Electron Transfer.

    PubMed

    Nishio, Koichi; Pornpitra, Tunanunkul; Izawa, Seiichiro; Nishiwaki-Ohkawa, Taeko; Kato, Souichiro; Hashimoto, Kazuhito; Nakanishi, Shuji

    2015-06-01

    Recent research on cellular circadian rhythms suggests that the coupling of transcription-translation feedback loops and intracellular redox oscillations is essential for robust circadian timekeeping. For clarification of the molecular mechanism underlying the circadian rhythm, methods that allow for the dynamic and simultaneous detection of transcription/translation and redox oscillations in living cells are needed. Herein, we report that the cyanobacterial circadian redox rhythm can be electrochemically detected based on extracellular electron transfer (EET), a process in which intracellular electrons are exchanged with an extracellular electrode. As the EET-based method is non-destructive, concurrent detection with transcription/translation rhythm using bioluminescent reporter strains becomes possible. An EET pathway that electrochemically connected the intracellular region of cyanobacterial cells with an extracellular electrode was constructed via a newly synthesized electron mediator with cell membrane permeability. In the presence of the mediator, the open circuit potential of the culture medium exhibited temperature-compensated rhythm with approximately 24 h periodicity. Importantly, such circadian rhythm of the open circuit potential was not observed in the absence of the electron mediator, indicating that the EET process conveys the dynamic information regarding the intracellular redox state to the extracellular electrode. These findings represent the first direct demonstration of the intracellular circadian redox rhythm of cyanobacterial cells. PMID:25975263

  2. Bipolar stacked quasi-all-solid-state lithium secondary batteries with output cell potentials of over 6 V

    NASA Astrophysics Data System (ADS)

    Matsuo, Takahiro; Gambe, Yoshiyuki; Sun, Yan; Honma, Itaru

    2014-08-01

    Designing a lithium ion battery (LIB) with a three-dimensional device structure is crucial for increasing the practical energy storage density by avoiding unnecessary supporting parts of the cell modules. Here, we describe the superior secondary battery performance of the bulk all-solid-state LIB cell and a multilayered stacked bipolar cell with doubled cell potential of 6.5 V, for the first time. The bipolar-type solid LIB cell runs its charge/discharge cycle over 200 times in a range of 0.1-1.0 C with negligible capacity decrease despite their doubled output cell potentials. This extremely high performance of the bipolar cell is a result of the superior battery performance of the single cell; the bulk all-solid-state cell has a charge/discharge cycle capability of over 1500 although metallic lithium and LiFePO4 are employed as anodes and cathodes, respectively. The use of a quasi-solid electrolyte consisting of ionic liquid and Al2O3 nanoparticles is considered to be responsible for the high ionic conductivity and electrochemical stability at the interface between the electrodes and the electrolyte. This paper presents the effective applications of SiO2, Al2O3, and CeO2 nanoparticles and various Li+ conducting ionic liquids for the quasi-solid electrolytes and reports the best ever known cycle performances. Moreover, the results of this study show that the bipolar stacked three-dimensional device structure would be a smart choice for future LIBs with higher cell energy density and output potential. In addition, our report presents the advantages of adopting a three-dimensional cell design based on the solid-state electrolytes, which is of particular interest in energy-device engineering for mobile applications.

  3. Continuous in situ electrochemical monitoring of doxorubicin efflux from sensitive and drug-resistant cancer cells.

    PubMed Central

    Yi, C; Gratzl, M

    1998-01-01

    One of the least well understood problems in cancer chemotherapy is the cross-resistance of certain tumor cells to a series of chemically unrelated drugs. Multidrug resistance (MDR) can be attributed to several different biophysical processes, among them increased drug efflux. This has been found to correlate with overexpression of the cell surface 170-kDa P-glycoprotein that actively excludes cytotoxic drugs against their concentration gradient. To better understand MDR, experimental methods are needed to study drug efflux from cancer cells. Continuous measurement of efflux of nonfluorescent drugs on the same cell culture in situ, or assessing efflux from a few cells or even a single cell, is beyond the capabilities of existing technologies. In this work, a carbon fiber (CF) microelectrode is used to monitor efflux of doxorubicin from a monolayer of two cell lines: an auxotrophic mutant of Chinese hamster ovary cells, AUXB1, and its MDR subline, CHRC5. Because doxorubicin is both fluorescent and electroactive, the results could be validated against existing data obtained optically and with other techniques on the same cell lines, with good agreement found. The electrochemical detection, however, is capable of in situ monitoring with high temporal resolution and is suitable for single-cell studies. PMID:9788921

  4. An ultra-high vacuum electrochemical flow cell for in situ/operando soft X-ray spectroscopy study

    SciTech Connect

    Bora, Debajeet K. E-mail: jguo@lbl.gov; Glans, Per-Anders; Pepper, John; Liu, Yi-Sheng; Guo, J.-H. E-mail: jguo@lbl.gov; Du, Chun; Wang, Dunwei

    2014-04-15

    An in situ flow electrochemical cell has been designed and fabricated to allow better seal under UHV chamber thus to achieve a good signal to noise ratio in fluorescence yield detection of X-ray absorption spectra for spectroelectrochemical study. The cell also stabilizes the thin silicon nitride membrane window in an effective manner so that the liquid cell remains intact during X-ray absorption experiments. With the improved design of the liquid cell, electrochemical experiments such as cyclic voltammetry have been performed for 10 cycles with a good stability of sample window. Also an operando electrochemical experiment during photoelectrochemistry has been performed on n-type hematite electrode deposited on silicon nitride window. The experiment allows us to observe the formation of two extra electronic transitions before pre edge of O K-edge spectra.

  5. Recent progress on the development of biofuel cells for self-powered electrochemical biosensing and logic biosensing: A review

    DOE PAGESBeta

    Zhou, Ming

    2015-06-12

    Biofuel cells (BFCs) based on enzymes and microorganisms have been recently received considerable attention because they are recognized as an attractive type of energy conversion technology. In addition to the research activities related to the application of BFCs as power source, we have witnessed recently a growing interest in using BFCs for self-powered electrochemical biosensing and electrochemical logic biosensing applications. Compared with traditional biosensors, one of the most significant advantages of the BFCs-based self-powered electrochemical biosensors and logic biosensors is their ability to detect targets integrated with chemical-to-electrochemical energy transformation, thus obviating the requirement of external power sources. Following mymore »previous review (Electroanalysis 2012, 24, 197-209), the present review summarizes, discusses and updates the most recent progress and latest advances on the design and construction of BFCs-based self-powered electrochemical biosensors and logic biosensors. In addition to the traditional approaches based on substrate effect, inhibition effect, blocking effect and gene regulation effect for BFCs-based self-powered electrochemical biosensors and logic biosensors design, some new principles including enzyme effect, co-stabilization effect, competition effect and hybrid effect are summarized and discussed by me in details. The outlook and recommendation of future directions of BFCs-based self-powered electrochemical biosensors and logic biosensors are discussed in the end.« less

  6. Recent progress on the development of biofuel cells for self-powered electrochemical biosensing and logic biosensing: A review

    SciTech Connect

    Zhou, Ming

    2015-06-12

    Biofuel cells (BFCs) based on enzymes and microorganisms have been recently received considerable attention because they are recognized as an attractive type of energy conversion technology. In addition to the research activities related to the application of BFCs as power source, we have witnessed recently a growing interest in using BFCs for self-powered electrochemical biosensing and electrochemical logic biosensing applications. Compared with traditional biosensors, one of the most significant advantages of the BFCs-based self-powered electrochemical biosensors and logic biosensors is their ability to detect targets integrated with chemical-to-electrochemical energy transformation, thus obviating the requirement of external power sources. Following my previous review (Electroanalysis 2012, 24, 197-209), the present review summarizes, discusses and updates the most recent progress and latest advances on the design and construction of BFCs-based self-powered electrochemical biosensors and logic biosensors. In addition to the traditional approaches based on substrate effect, inhibition effect, blocking effect and gene regulation effect for BFCs-based self-powered electrochemical biosensors and logic biosensors design, some new principles including enzyme effect, co-stabilization effect, competition effect and hybrid effect are summarized and discussed by me in details. The outlook and recommendation of future directions of BFCs-based self-powered electrochemical biosensors and logic biosensors are discussed in the end.

  7. Pure red cell aplasia secondary to treatment with erythropoietin.

    PubMed

    Locatelli, Francesco; Del Vecchio, Lucia

    2003-01-01

    Pure red cell aplasia (PRCA) is a rare condition defined as severe anemia secondary to the virtual absence of red blood cell precursors in the bone marrow. In the setting of patients treated with rHuEPO, the disease is generated by epoetin-induced antibodies that neutralise all the exogenous rHuEPO and cross-react with endogenous erythropoietin. As a result, serum erythropoietin levels are undetectable and erythropoiesis becomes ineffective. Only 4 cases of PRCA associated with rh-EPO have been reported before 1998. Thereafter, a sharp increase in the incidence of this rare condition has been reported, mainly associated with epoetin alpha use outside the United States. A number of possible mechanisms leading to PRCA development have been identified. Among these, modification of drug formulation and down stream processing probably has had a major role. Indeed, in 1998 the formulation of epoetin alpha in Europe was modified because of the fear of the "mad cow" syndrome. However, differences in molecule structure and glycosylation among different epoetins can not be excluded. It should also be underlined that the rise in the incidence of PRCA cases has been coincident with a major shift from intravenous to subcutaneous administration of rHuEPO. The abrupt rise in the incidence of PRCA cases observed in the last few years, deserves particular attention; however, we have to balance its severity, but extreme rarity, with the high number of chronic kidney disease patients who die each year because of cardiovascular disease that could partially be reduced by anemia treatment. PMID:14696747

  8. Cyanobacteria as Cell Factories to Produce Plant Secondary Metabolites

    PubMed Central

    Xue, Yong; He, Qingfang

    2015-01-01

    Cyanobacteria represent a promising platform for the production of plant secondary metabolites. Their capacity to express plant P450 proteins, which have essential functions in the biosynthesis of many plant secondary metabolites, makes cyanobacteria ideal for this purpose, and their photosynthetic capability allows cyanobacteria to grow with simple nutrient inputs. This review summarizes the advantages of using cyanobacteria to transgenically produce plant secondary metabolites. Some techniques to improve heterologous gene expression in cyanobacteria are discussed. PMID:25973419

  9. Music Generated by a Zn/Cu Electrochemical Cell, a Lemon Cell, and a Solar Cell: A Demonstration for General Chemistry

    ERIC Educational Resources Information Center

    Cady, Susan G.

    2014-01-01

    The circuit board found in a commercial musical greeting card is used to supply music for electrochemical cell demonstrations. Similar to a voltmeter, the "modified" musical device is connected to a chemical reaction that produces electricity. The commercial 1 V battery inside the greeting card circuit board can be replaced with an…

  10. Electrochemical impregnation and cycle life of lightweight nickel electrodes for nickel-hydrogen cells

    NASA Technical Reports Server (NTRS)

    Britton, Doris L.

    1990-01-01

    Development of a high specific energy nickel electrode is the main goal of the lightweight nickel electrode program at NASA-Lewis. The approach was to improve the nickel electrode by continuing combined in-house and contract efforts to develop a more efficient and lighter weight electrode for the nickel-hydrogen cell. Lightweight plaques are used as conductive supports for the nickel hydroxide active material. These plaques are commercial products that are fabricated into nickel electrodes by electrochemically impregnating them with active material. The electrodes are life cycle tested in a low Earth orbit regime at 40 and 80 percent depths-of-discharge.

  11. Supporting electrodes for solid oxide fuel cells and other electrochemical devices

    DOEpatents

    Sprenkle, Vincent L. (Richland, WA); Canfield, Nathan L. (Kennewick, WA); Meinhardt, Kerry (Kennewick, WA); Stevenson, Jeffry W. (Richland, WA)

    2008-04-01

    An electrode supported electrolyte membrane includes an electrode layer 630 facing an electrolyte layer 620. The opposing side of the electrode layer 630 includes a backing layer 640 of a material with a thermal expansion coefficient approximately equal to the thermal expansion coefficient of the electrolyte layer 620. The backing layer 640 is in a two dimensional pattern that covers only a portion of the electrolyte layer 630. An electrochemical cell such as a SOFC is formed by providing a cathode layer 610 on an opposing side of the electrolyte layer 620.

  12. Engineering charge injection interfaces in hybrid light-emitting electrochemical cells.

    PubMed

    Roldán-Carmona, Cristina; Akatsuka, Takeo; Sessolo, Michele; Watkins, Scott E; Bolink, Henk J

    2014-11-26

    Light-emitting electrochemical cells (LECs) consists of a thin film of an ionic organic semiconductor sandwiched between two electrodes. Because of the large density of ions, LECs are often reported to perform independently on the electrodes work function. Here we use metal oxides as charge injection layers and demonstrate that, although electroluminescence is observed independently of the electrodes used, the device performances are strongly dependent on the choice of the interface materials. Relying on metal oxide charge injection layers, such hybrid devices are of interest for real lighting applications and could pave the way for new efficient, stable, low-cost lighting sources. PMID:25372865

  13. Electrochemical impregnation and cycle life of lightweight nickel electrodes for nickel-hydrogen cells

    NASA Technical Reports Server (NTRS)

    Britton, Doris L.

    1990-01-01

    Development of a high specific energy nickel electrode is the main goal of the lightweight nickel electrode program at NASA-Lewis. The approach was to improve the nickel electrode by continuing combined in-house and contract efforts to develop a more efficient and lighter weight electrode for the nickel-hydrogen cell. Lightweight plaques are used as conductive supports for the nickel hydroxide active material. These plaques are commercial products that are fabricated into nickel electrodes by electrochemically impregnating them with active material. The electrodes are life cycle tested in a low earth orbit regime at 40 and 80 percent depths-of-discharge.

  14. Biological capacitance studies of anodes in microbial fuel cells using electrochemical impedance spectroscopy.

    PubMed

    Lu, Zhihao; Girguis, Peter; Liang, Peng; Shi, Haifeng; Huang, Guangtuan; Cai, Lankun; Zhang, Lehua

    2015-07-01

    It is known that cell potential increases while anode resistance decreases during the start-up of microbial fuel cells (MFCs). Biological capacitance, defined as the apparent capacitance attributed to biological activity including biofilm production, plays a role in this phenomenon. In this research, electrochemical impedance spectroscopy was employed to study anode capacitance and resistance during the start-up period of MFCs so that the role of biological capacitance was revealed in electricity generation by MFCs. It was observed that the anode capacitance ranged from 3.29 to 120 mF which increased by 16.8% to 18-20 times over 10-12 days. Notably, lowering the temperature and arresting biological activity via fixation by 4% para formaldehyde resulted in the decrease of biological capacitance by 16.9 and 62.6%, indicating a negative correlation between anode capacitance and anode resistance of MFCs. Thus, biological capacitance of anode should play an important role in power generation by MFCs. We suggest that MFCs are not only biological reactors and/or electrochemical cells, but also biological capacitors, extending the vision on mechanism exploration of electron transfer, reactor structure design and electrode materials development of MFCs. PMID:25656699

  15. Synthesis of mesoporous nanocomposites for their application in solid oxide electrolysers cells: microstructural and electrochemical characterization.

    PubMed

    Torrell, M; Almar, L; Morata, A; Tarancón, A

    2015-10-10

    Fabrication routes for new SOEC mesoporous nanocomposite materials as electrodes are presented in this paper. NiO-CGO and SDC-SSC are described as possible new materials and their synthesis and the cell fabrication are discussed. The obtained materials are microstructurally characterised by SEM, TEM and XRD, where the mesoporous structures are observed and analysed. The obtained samples are electrochemically analysed by I-V polarisation curves and EIS analysis, showing a maximum current density of 330 mA cm(-2) at 1.7 V. A degradation of the cell performance is evidenced after a potentiostatic test at 1.4 V after more than 40 hours. Oxygen electrode delaminating is detected, which is most probably the main cause of ageing. Even taking into account the lack of durability of the fabricated cells, the mesoporous electrodes do not seem to be altered, opening the possibility for further studies devoted to this high stability material for SOEC electrodes. PMID:26212761

  16. The Lead-Lead Oxide Secondary Cell as a Teaching Resource

    ERIC Educational Resources Information Center

    Smith, Michael J.; Fonseca, Antonio M.; Silva, M. Manuela

    2009-01-01

    The assembly and use of a laboratory version of a secondary cell based on the lead-lead oxide system is described. The cell is easy to construct, sufficiently robust for student use, and has a conveniently low practical capacity of about 5 mA h. This modest cell capacity allows cell assembly, electrode formation and discharge characterization…

  17. A repeatable assembling and disassembling electrochemical aptamer cytosensor for ultrasensitive and highly selective detection of human liver cancer cells.

    PubMed

    Sun, Duanping; Lu, Jing; Chen, Zuanguang; Yu, Yanyan; Mo, Manni

    2015-07-23

    In this work, a repeatable assembling and disassembling electrochemical aptamer cytosensor was proposed for the sensitive detection of human liver hepatocellular carcinoma cells (HepG2) based on a dual recognition and signal amplification strategy. A high-affinity thiolated TLS11a aptamer, covalently attached to a gold electrode through Au-thiol interactions, was adopted to recognize and capture the target HepG2 cells. Meanwhile, the G-quadruplex/hemin/aptamer and horseradish peroxidase (HRP) modified gold nanoparticles (G-quadruplex/hemin/aptamer-AuNPs-HRP) nanoprobe was designed. It could be used for electrochemical cytosensing with specific recognition and enzymatic signal amplification of HRP and G-quadruplex/hemin HRP-mimicking DNAzyme. With the nanoprobes as recognizing probes, the HepG2 cancer cells were captured to fabricate an aptamer-cell-nanoprobes sandwich-like superstructure on a gold electrode surface. The proposed electrochemical cytosensor delivered a wide detection range from 1×10(2) to 1×10(7) cells mL(-1) and high sensitivity with a low detection limit of 30 cells mL(-1). Furthermore, after the electrochemical detection, the activation potential of -0.9 to -1.7V was performed to break Au-thiol bond and regenerate a bare gold electrode surface, while maintaining the good characteristic of being used repeatedly. The changes of gold electrode behavior after assembling and desorption processes were investigated by electrochemical impedance spectroscopy and cyclic voltammetry techniques. These results indicate that the cytosensor has great potential in disease diagnostic of cancers and opens new insight into the reusable gold electrode with repeatable assembling and disassembling in the electrochemical sensing. PMID:26231902

  18. Navigating the transcriptional roadmap regulating plant secondary cell wall deposition

    PubMed Central

    Hussey, Steven G.; Mizrachi, Eshchar; Creux, Nicky M.; Myburg, Alexander A.

    2013-01-01

    The current status of lignocellulosic biomass as an invaluable resource in industry, agriculture, and health has spurred increased interest in understanding the transcriptional regulation of secondary cell wall (SCW) biosynthesis. The last decade of research has revealed an extensive network of NAC, MYB and other families of transcription factors regulating Arabidopsis SCW biosynthesis, and numerous studies have explored SCW-related transcription factors in other dicots and monocots. Whilst the general structure of the Arabidopsis network has been a topic of several reviews, they have not comprehensively represented the detailed protein–DNA and protein–protein interactions described in the literature, and an understanding of network dynamics and functionality has not yet been achieved for SCW formation. Furthermore the methodologies employed in studies of SCW transcriptional regulation have not received much attention, especially in the case of non-model organisms. In this review, we have reconstructed the most exhaustive literature-based network representations to date of SCW transcriptional regulation in Arabidopsis. We include a manipulable Cytoscape representation of the Arabidopsis SCW transcriptional network to aid in future studies, along with a list of supporting literature for each documented interaction. Amongst other topics, we discuss the various components of the network, its evolutionary conservation in plants, putative modules and dynamic mechanisms that may influence network function, and the approaches that have been employed in network inference. Future research should aim to better understand network function and its response to dynamic perturbations, whilst the development and application of genome-wide approaches such as ChIP-seq and systems genetics are in progress for the study of SCW transcriptional regulation in non-model organisms. PMID:24009617

  19. A Synopsis of Interfacial Phenomena in Lithium-Based Polymer Electrolyte Electrochemical Cells

    NASA Technical Reports Server (NTRS)

    Baldwin, Richard S.; Bennett, William R.

    2007-01-01

    The interfacial regions between electrode materials, electrolytes and other cell components play key roles in the overall performance of lithium-based batteries. For cell chemistries employing lithium metal, lithium alloy or carbonaceous materials (i.e., lithium-ion cells) as anode materials, a "solid electrolyte interphase" (SEI) layer forms at the anode/electrolyte interface, and the properties of this "passivating" layer significantly affect the practical cell/battery quality and performance. A thin, ionically-conducting SEI on the electrode surface can beneficially reduce or eliminate undesirable side reactions between the electrode and the electrolyte, which can result in a degradation in cell performance. The properties and phenomena attributable to the interfacial regions existing at both anode and cathode surfaces can be characterized to a large extent by electrochemical impedance spectroscopy (EIS) and related techniques. The intention of the review herewith is to support the future development of lithium-based polymer electrolytes by providing a synopsis of interfacial phenomena that is associated with cell chemistries employing either lithium metal or carbonaceous "composite" electrode structures which are interfaced with polymer electrolytes (i.e., "solvent-free" as well as "plasticized" polymer-binary salt complexes and single ion-conducting polyelectrolytes). Potential approaches to overcoming poor cell performance attributable to interfacial effects are discussed.

  20. Allicin disrupts the cell's electrochemical potential and induces apoptosis in yeast.

    PubMed

    Gruhlke, Martin C H; Portz, Daniela; Stitz, Michael; Anwar, Awais; Schneider, Thomas; Jacob, Claus; Schlaich, Nikolaus L; Slusarenko, Alan J

    2010-12-15

    The volatile substance allicin gives crushed garlic (Allium sativum) its characteristic odor and is a pro-oxidant that undergoes thiol-disulfide exchange reactions with -SH groups in proteins and glutathione. The antimicrobial activity of allicin is suspected to be due to the oxidative inactivation of essential thiol-containing enzymes. We investigated the hypothesis that at threshold inhibitory levels allicin can shunt yeast cells into apoptosis by altering their overall redox status. Yeast cells were treated either with chemically synthesized, pure allicin or with allicin in garlic juice. Allicin-dependent cell oxidation was demonstrated with a redox-sensitive GFP construct and the shift in cellular electrochemical potential (E(hc)) from less than -215 to -181mV was calculated using the Nernst equation after the glutathione/glutathione disulfide couple (2GSH/GSSG) in the cell was quantified. Caspase activation occurred after allicin treatment, and yeast expressing a human antiapoptotic Bcl-XL construct was rendered more resistant to allicin. Also, a yeast apoptosis-inducing factor deletion mutant was more resistant to allicin than wild-type cells. We conclude that allicin in garlic juice can activate apoptosis in yeast cells through its oxidizing properties and that this presents an alternative cell-killing mechanism to the previously proposed specific oxidative inactivation of essential enzymes. PMID:20883774

  1. Characterization and optimization of cathodic conditions for H2O2 synthesis in microbial electrochemical cells.

    PubMed

    Sim, Junyoung; An, Junyeong; Elbeshbishy, Elsayed; Ryu, Hodon; Lee, Hyung-Sool

    2015-11-01

    Cathode potential and O2 supply methods were investigated to improve H2O2 synthesis in an electrochemical cell, and optimal cathode conditions were applied for microbial electrochemical cells (MECs). Using aqueous O2 for the cathode significantly improved current density, but H2O2 conversion efficiency was negligible at 0.3-12%. Current density decreased for passive O2 diffusion to the cathode, but H2O2 conversion efficiency increased by 65%. An MEC equipped with a gas diffusion cathode was operated with acetate medium and domestic wastewater, which presented relatively high H2O2 conversion efficiency from 36% to 47%, although cathode overpotential was fluctuated. Due to different current densities, the maximum H2O2 production rate was 141 mg H2O2/L-h in the MEC fed with acetate medium, but it became low at 6 mg H2O2/L-h in the MEC fed with the wastewater. Our study clearly indicates that improving anodic current density and mitigating membrane fouling would be key parameters for large-scale H2O2-MECs. PMID:26141667

  2. Method of forming a plasma sprayed interconnection layer on an electrode of an electrochemical cell

    DOEpatents

    Spengler, C.J.; Folser, G.R.; Vora, S.D.; Kuo, L.; Richards, V.L.

    1995-06-20

    A dense, substantially gas-tight, electrically conductive interconnection layer is formed on an air electrode structure of an electrochemical cell by (A) providing an electrode surface; (B) forming on a selected portion of the electrode surface, a layer of doped LaCrO{sub 3} particles doped with an element selected from Ca, Sr, Ba, Mg, Co, Ni, Al and mixtures thereof by plasma spraying doped LaCrO{sub 3} powder, preferably compensated with chromium as Cr{sub 2}O{sub 3} and/or dopant element, preferably by plasma arc spraying; and, (C) heating the doped and compensated LaCrO{sub 3} layer to about 1100 C to 1300 C to provide a dense, substantially gas-tight, substantially hydration-free, electrically conductive interconnection material bonded to the electrode surface. A solid electrolyte layer can be applied to the unselected portion of the air electrode, and a fuel electrode can be applied to the solid electrolyte, to provide an electrochemical cell. 6 figs.

  3. Method of forming a plasma sprayed interconnection layer on an electrode of an electrochemical cell

    DOEpatents

    Spengler, Charles J. (Murrysville, PA); Folser, George R. (Lower Burrell, PA); Vora, Shailesh D. (Monroeville, PA); Kuo, Lewis (Monroeville, PA); Richards, Von L. (Anyola, IN)

    1995-01-01

    A dense, substantially gas-tight, electrically conductive interconnection layer is formed on an air electrode structure of an electrochemical cell by (A) providing an electrode surface; (B) forming on a selected portion of the electrode surface, a layer of doped LaCrO.sub.3 particles doped with an element selected from Ca, Sr, Ba, Mg, Co, Ni, Al and mixtures thereof by plasma spraying doped LaCrO.sub.3 powder, preferably compensated with chromium as Cr.sub.2 O.sub.3 and/or dopant element, preferably by plasma arc spraying; and, (C) heating the doped and compensated LaCrO.sub.3 layer to about 1100.degree. C. to 1300.degree. C. to provide a dense, substantially gas-tight, substantially hydration-free, electrically conductive interconnection material bonded to the electrode surface. A solid electrolyte layer can be applied to the unselected portion of the air electrode, and a fuel electrode can be applied to the solid electrolyte, to provide an electrochemical cell.

  4. Bond nature of active metal ions in SiO2-based electrochemical metallization memory cells.

    PubMed

    Cho, Deok-Yong; Tappertzhofen, Stefan; Waser, Rainer; Valov, Ilia

    2013-03-01

    Electrochemical metallization cells are candidates for the next-generation non-volatile memory devices based on resistive switching. Despite the intensive studies in recent years a microscopic model of the processes in these nanoscale electrochemical systems is still missing and the physicochemical properties of the active metal ions have been rarely reported. We examined the bonding characteristics of Cu(z+) and Ag(+) ions in SiO(2)-based cells using soft X-ray absorption spectroscopy. Whereas the Ag/SiO(2) interfaces showed no chemical interaction of Ag ions, the Cu/SiO(2) showed clear signatures of partial oxidation into two ionic species of Cu(2+) and Cu(+). The analyses on the orbital hybridization strength evidently showed that the Cu(2+)-O(2-) bonds in SiO(2) are much weaker than the Cu(+)-O(2-) bonds, analogous to the case of bulk CuO and Cu(2)O. This suggests that the Cu(2+) ions should be more mobile and with a dominating role in the process of resistive switching. PMID:23354222

  5. Electrochemical monitoring of an important biomarker and target protein: VEGFR2 in cell lysates.

    PubMed

    Wei, Tianxiang; Tu, Wenwen; Zhao, Bo; Lan, Yaqian; Bao, Jianchun; Dai, Zhihui

    2014-01-01

    Vascular endothelial growth factor receptor 2 (VEGFR2) is a potential cell-type biomarker in clinical diagnoses. Besides, it's the target protein of many tyrosine kinase inhibitors and its expression significantly associates with clinical performance of these inhibitors. VEGFR2 detection provides an early warning for diseases and a basis for therapy and drug screening. Some methods have been developed for VEGFR2 determination. However, they are usually performed indirectly and complexly. Herein, an electrochemical biosensing platform for VEGFR2 analysis has been first proposed. It can detect the total concentrations of the VEGFR2 protein in cells lysates directly and can be used to monitor the changes of VEGFR2 expression levels induced by treatments of different inhibitors. Moreover, the inhibitor-VEGFR2 interactions are illuminated through theoretical simulation. The simulation results agree well with the experimental data, indicating the veracity of the proposed method. The electrochemical detection methodology for VEGFR2 would be promising in clinical diagnosis and drug screening. PMID:24496270

  6. Real-Time Evaluation of Live Cancer Cells by an in Situ Surface Plasmon Resonance and Electrochemical Study.

    PubMed

    Wu, Changyu; Rehman, Fawad Ur; Li, Jingyuan; Ye, Jing; Zhang, Yuanyuan; Su, Meina; Jiang, Hui; Wang, Xuemei

    2015-11-11

    This work presents a new strategy of the combination of surface plasmon resonance (SPR) and electrochemical study for real-time evaluation of live cancer cells treated with daunorubicin (DNR) at the interface of the SPR chip and living cancer cells. The observations demonstrate that the SPR signal changes could be closely related to the morphology and mass changes of adsorbed cancer cells and the variation of the refractive index of the medium solution. The results of light microscopy images and 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide studies also illustrate the release or desorption of HepG2 cancer cells, which were due to their apoptosis after treatment with DNR. It is evident that the extracellular concentration of DNR residue can be readily determined through electrochemical measurements. The decreases in the magnitudes of SPR signals were linearly related to cell survival rates, and the combination of SPR with electrochemical study could be utilized to evaluate the potential therapeutic efficiency of bioactive agents to cells. Thus, this label-free, real-time SPR-electrochemical detection technique has great promise in bioanalysis or monitoring of relevant treatment processes in clinical applications. PMID:26492438

  7. The Electrochemical Behavior of Anodically Electrodeposited Iridium Oxide Films and the Reliability of Transmittance Variable Cells

    NASA Astrophysics Data System (ADS)

    Yamanaka, Kazusuke

    1991-06-01

    The electrochemical properties of anodically electrodeposited iridium oxide films are investigated for application to transmittance variable cells. The reactivity of electrochromic reaction of the film increases with the increase in water content in LiClO4 propylene carbonate electrolyte, and decreases with increasing temperature of the heat treatment after electrodeposition. The coloration potential E of the film depends on the proton activity in the electrolyte, and increases linearly with the hydrogen electrode potential E' of the electrolyte at a slope of 1.0. This means that the coloration is caused by the release of H+ from the film or by the injection of OH- into the film. The reliability of transmittance variable cells made with the films is tested.

  8. Electrodes and electrochemical storage cells utilizing tin-modified active materials

    DOEpatents

    Anani, Anaba (Lauderhill, FL); Johnson, John (Calverton, NY); Lim, Hong S. (Agoura Hills, CA); Reilly, James (Bellport, NY); Schwarz, Ricardo (Los Alamos, NM); Srinivasan, Supramaniam (College Station, TX)

    1995-01-01

    An electrode has a substrate and a finely divided active material on the substrate. The active material is ANi.sub.x-y-z Co.sub.y Sn.sub.z, wherein A is a mischmetal or La.sub.1-w M.sub.w, M is Ce, Nd, or Zr, w is from about 0.05 to about 1.0, x is from about 4.5 to about 5.5, y is from 0 to about 3.0, and z is from about 0.05 to about 0.5. An electrochemical storage cell utilizes such an electrode as the anode. The storage cell further has a cathode, a separator between the cathode and the anode, and an electrolyte.

  9. Synthesis of bulk superconducting La sub 2 CuO sub 4 in an electrochemical cell

    SciTech Connect

    Bennett, J.C.; Olfert, M.; Scholz, G.A.; Boswell, F.W. )

    1991-08-01

    Superconductivity has been observed in originally semiconducting ceramic samples of La{sub 2}CuO{sub 4} following oxidation in an electrochemical cell at room temperature. After processing, the room-temperature resistivity is lowered by over an order of magnitude and, on cooling below 150 K, acquires a metallic temperature dependence. The superconducting transition occurs near 45 K. Magnetic-susceptibility measurements confirm the bulk nature of the superconductivity. Furthermore, by reversing the polarization of the cell, semiconducting La{sub 2}CuO{sub 4} can again be produced. The homogeneity of the processed samples was verified by x-ray powder diffraction and energy-dispersive x-ray elemental analysis.

  10. Electrochemical characterization of Geobacter sulfurreducens cells immobilized on graphite paper electrodes.

    PubMed

    Srikanth, Shweta; Marsili, Enrico; Flickinger, Michael C; Bond, Daniel R

    2008-04-01

    Bacteria able to transfer electrons to conductive surfaces are of interest as catalysts in microbial fuel cells, as well as in bioprocessing, bioremediation, and corrosion. New procedures for immobilization of Geobacter sulfurreducens on graphite electrodes are described that allow routine, repeatable electrochemical analysis of cell-electrode interactions. Immediately after immobilizing G. sulfurreducens on electrodes, electrical current was obtained without addition of exogenous electron shuttles or electroactive polymers. Voltammetry and impedance analysis of pectin-immobilized bacteria transferring electrons to electrode surfaces could also be performed. Cyclic voltammetry of immobilized cells revealed voltage-dependent catalytic current similar to what is commonly observed with adsorbed enzymes, with catalytic waves centered at -0.15 V (vs. SHE). Electrodes maintained at +0.25 V (vs. SHE) initially produced 0.52 A/m(2) in the presence of acetate as the electron donor. Electrical Impedance Spectroscopy of coatings was also consistent with a catalytic mechanism, controlled by charge transfer rate. When electrodes were maintained at an oxidizing potential for 24 h, electron transfer to electrodes increased to 1.75 A/m(2). These observations of electron transfer by pectin-entrapped G. sulfurreducens appear to reflect native mechanisms used for respiration. The ability of washed G. sulfurreducens cells to immediately produce electrical current was consistent with the external surface of this bacterium possessing a pathway linking oxidative metabolism to extracellular electron transfer. This electrochemical activity of pectin-immobilized bacteria illustrates a strategy for preparation of catalytic electrodes and study of Geobacter under defined conditions. PMID:17929324

  11. Electrochemical fuel cell generator having an internal and leak tight hydrocarbon fuel reformer

    DOEpatents

    Dederer, Jeffrey T. (Valencia, PA); Hager, Charles A. (Mars, PA)

    1998-01-01

    An electrochemical fuel cell generator configuration is made having a generator section which contains a plurality of axially elongated fuel cells, each cell containing a fuel electrode, air electrode, and solid oxide electrolyte between the electrodes, in which axially elongated dividers separate portions of the fuel cells from each other, and where at least one divider also reforms a reformable fuel gas mixture prior to electricity generation reactions, the at least one reformer-divider is hollow having a closed end and an open end entrance for a reformable fuel mixture to pass to the closed end of the divider and then reverse flow and pass back along the hollowed walls to be reformed, and then finally to pass as reformed fuel out of the open end of the divider to contact the fuel cells, and further where the reformer-divider is a composite structure having a gas diffusion barrier of metallic foil surrounding the external walls of the reformer-divider except at the entrance to prevent diffusion of the reformable gas mixture through the divider, and further housed in an outer insulating jacket except at the entrance to prevent short-circuiting of the fuel cells by the gas diffusion barrier.

  12. Electrochemical and physical analysis of a Li-ion cell cycled at elevated temperature

    SciTech Connect

    Shim, Joongpyo; Kostecki, Robert; Richardson, Thomas; Song, Xiangyun; Striebel, Kathryn A.

    2002-06-21

    Laboratory-size LiNi0.8Co0.15Al0.05O2/graphite lithium-ion pouch cells were cycled over 100 percent DOD at room temperature and 60 degrees C in order to investigate high-temperature degradation mechanisms of this important technology. Capacity fade for the cell was correlated with that for the individual components, using electrochemical analysis of the electrodes and other diagnostic techniques. The high-temperature cell lost 65 percent of its initial capacity after 140 cycles at 60 degrees C compared to only 4 percent loss for the cell cycled at room temperature. Cell ohmic impedance increased significantly with the elevated temperature cycling, resulting in some of loss of capacity at the C/2 rate. However, as determined with slow rate testing of the individual electrodes, the anode retained most of its original capacity, while the cathode lost 65 percent, even when cycled with a fresh source of lithium. Diagnostic evaluation of cell components including XRD, Raman, CSAFM and suggest capacity loss occurs primarily due to a rise in the impedance of the cathode, especially at the end-of-charge. The impedance rise may be caused in part by a loss of the conductive carbon at the surface of the cathode and/or by an organic film on the surface of the cathode that becomes non-ionically conductive at low lithium content.

  13. Electrochemical performance of silver/molybdotungstate-amorphous-electrolyte cells with charge-transfer-complex cathodes

    NASA Astrophysics Data System (ADS)

    Sathya Sainath Prasad, P.; Radhakrishna, S.

    For the quaternary fast ion conducting system AgI?Ag 2O?MoO 3?WO 3, the highest ionic conductivity, 5.1 × 10 -2 (? cm) -1, was observed when using an amorphous electrolyte composition of 80%AgI-13.33%Ag 2O-6.66% (0.7MoO 3-0.3WO 3). This electrolyte was used in the fabrication of solid-state electrochemical cells with the configuration (anode)/(amorphous electrolyte)/(cathode). The anode consisted of silver while a variety of organic charge-transfer-complex materials was employed as cathodes. The latter included phenothiazene, pyrene, and 2-perylene·3I 2. Cell performance was assessed by studying open-circuit voltage (OCV), anodic and cathodic polarisation, current discharge capability, and load discharge characteristics. It was found that the cell with a 2-perylene·3I 2 cathode yielded the highest OCV (657 mV) without any anodic or cathodic polarisation. The cell exhibited an internal resistance of 32 ? and a short-circuit current of 10 mA with a rechargeability having marginal coulombic efficiency. The diffusion co-efficients of silver ion were evaluated from the time dependence of cell voltage as a function of current density. The optimum current density ( i.e., that giving no polarisation) was fixed and the load curves were recorded to evaluate the applicability of the cells to micropower sources and low-energy-density silver batteries.

  14. Electrochemical fuel cell generator having an internal and leak tight hydrocarbon fuel reformer

    DOEpatents

    Dederer, J.T.; Hager, C.A.

    1998-03-31

    An electrochemical fuel cell generator configuration is made having a generator section which contains a plurality of axially elongated fuel cells, each cell containing a fuel electrode, air electrode, and solid oxide electrolyte between the electrodes, in which axially elongated dividers separate portions of the fuel cells from each other, and where at least one divider also reforms a reformable fuel gas mixture prior to electricity generation reactions, the at least one reformer-divider is hollow having a closed end and an open end entrance for a reformable fuel mixture to pass to the closed end of the divider and then reverse flow and pass back along the hollowed walls to be reformed, and then finally to pass as reformed fuel out of the open end of the divider to contact the fuel cells, and further where the reformer-divider is a composite structure having a gas diffusion barrier of metallic foil surrounding the external walls of the reformer-divider except at the entrance to prevent diffusion of the reformable gas mixture through the divider, and further housed in an outer insulating jacket except at the entrance to prevent short-circuiting of the fuel cells by the gas diffusion barrier. 10 figs.

  15. Laccases Direct Lignification in the Discrete Secondary Cell Wall Domains of Protoxylem1[W][OPEN

    PubMed Central

    Schuetz, Mathias; Benske, Anika; Smith, Rebecca A.; Watanabe, Yoichiro; Tobimatsu, Yuki; Ralph, John; Demura, Taku; Ellis, Brian; Samuels, A. Lacey

    2014-01-01

    Plants precisely control lignin deposition in spiral or annular secondary cell wall domains during protoxylem tracheary element (TE) development. Because protoxylem TEs function to transport water within rapidly elongating tissues, it is important that lignin deposition is restricted to the secondary cell walls in order to preserve the plasticity of adjacent primary wall domains. The Arabidopsis (Arabidopsis thaliana) inducible VASCULAR NAC DOMAIN7 (VND7) protoxylem TE differentiation system permits the use of mutant backgrounds, fluorescent protein tagging, and high-resolution live-cell imaging of xylem cells during secondary cell wall development. Enzymes synthesizing monolignols, as well as putative monolignol transporters, showed a uniform distribution during protoxylem TE differentiation. By contrast, the oxidative enzymes LACCASE4 (LAC4) and LAC17 were spatially localized to secondary cell walls throughout protoxylem TE differentiation. These data support the hypothesis that precise delivery of oxidative enzymes determines the pattern of cell wall lignification. This view was supported by lac4lac17 mutant analysis demonstrating that laccases are necessary for protoxylem TE lignification. Overexpression studies showed that laccases are sufficient to catalyze ectopic lignin polymerization in primary cell walls when exogenous monolignols are supplied. Our data support a model of protoxylem TE lignification in which monolignols are highly mobile once exported to the cell wall, and in which precise targeting of laccases to secondary cell wall domains directs lignin deposition. PMID:25157028

  16. Photoelectrochemical and Electrochemical Characterization of Sub-Micro-Gram Amounts of Organic Semiconductors Using Scanning Droplet Cell Microscopy

    PubMed Central

    2014-01-01

    A model organic semiconductor (MDMO-PPV) was used for testing a modified version of a photoelectrochemical scanning droplet cell microscope (PE-SDCM) adapted for use with nonaqueous electrolytes and containing an optical fiber for localized illumination. The most attractive features of the PE-SDCM are represented by the possibility of addressing small areas on the investigated substrate and the need of small amounts of electrolyte. A very small amount (ng) of the material under study is sufficient for a complete electrochemical and photoelectrochemical characterization due to the scanning capability of the cell. The electrochemical behavior of the polymer was studied in detail using potentiostatic and potentiodynamic investigations as well as electrochemical impedance spectroscopy. Additionally, the photoelectrochemical properties were investigated under illumination conditions, and the photocurrents found were at least 3 orders of magnitude higher than the dark (background) current, revealing the usefulness of this compact microcell for photovoltaic characterizations. PMID:25101149

  17. Starting to Gel: How Arabidopsis Seed Coat Epidermal Cells Produce Specialized Secondary Cell Walls

    PubMed Central

    Voiniciuc, C?t?lin; Yang, Bo; Schmidt, Maximilian Heinrich-Wilhelm; Günl, Markus; Usadel, Björn

    2015-01-01

    For more than a decade, the Arabidopsis seed coat epidermis (SCE) has been used as a model system to study the synthesis, secretion and modification of cell wall polysaccharides, particularly pectin. Our detailed re-evaluation of available biochemical data highlights that Arabidopsis seed mucilage is more than just pectin. Typical secondary wall polymers such as xylans and heteromannans are also present in mucilage. Despite their low abundance, these components appear to play essential roles in controlling mucilage properties, and should be further investigated. We also provide a comprehensive community resource by re-assessing the mucilage phenotypes of almost 20 mutants using the same conditions. We conduct an in-depth functional evaluation of all the SCE genes described in the literature and propose a revised model for mucilage production. Further investigation of SCE cells will improve our understanding of plant cell walls. PMID:25658798

  18. Analysis of secondary cells with lithium anodes and immobilized fused-salt electrolytes

    NASA Technical Reports Server (NTRS)

    Cairns, E. J.; Rogers, G. L.; Shimotake, H.

    1969-01-01

    Secondary cells with liquid lithium anodes, liquid bismuth or tellurium cathodes, and fused lithium halide electrolytes immobilized as rigid pastes operate between 380 and 485 degrees. Applications include power sources in space, military vehicle propulsion and special commercial vehicle propulsion.

  19. Electrochemical device

    DOEpatents

    Grimes, Patrick G. (Westfield, NJ); Einstein, Harry (Springfield, NJ); Bellows, Richard J. (Westfield, NJ)

    1988-01-12

    A tunnel protected electrochemical device features channels fluidically communicating between manifold, tunnels and cells. The channels are designed to provide the most efficient use of auxiliary power. The channels have a greater hydraulic pressure drop and electrical resistance than the manifold. This will provide a design with the optimum auxiliary energy requirements.

  20. Electrochemical construction

    DOEpatents

    Einstein, Harry (Springfield, NJ); Grimes, Patrick G. (Westfield, NJ)

    1983-08-23

    An electrochemical cell construction features a novel co-extruded plastic electrode in an interleaved construction with a novel integral separator-spacer. Also featured is a leak and impact resistant construction for preventing the spill of corrosive materials in the event of rupture.

  1. An electrochemical cell for in operando studies of lithium/sodium batteries using a conventional x-ray powder diffractometer

    NASA Astrophysics Data System (ADS)

    Shen, Yanbin; Pedersen, Erik E.; Christensen, Mogens; Iversen, Bo B.

    2014-10-01

    An electrochemical cell has been designed for powder X-ray diffraction studies of lithium ion batteries (LIB) and sodium ion batteries (SIB) in operando with high time resolution using a conventional powder X-ray diffractometer. The cell allows for studies of both anode and cathode electrode materials in reflection mode. The cell design closely mimics that of standard battery testing coin cells and allows obtaining powder X-ray diffraction patterns under representative electrochemical conditions. In addition, the cell uses graphite as the X-ray window instead of beryllium, and it is easy to operate and maintain. Test examples on lithium insertion/extraction in two spinel-type LIB electrode materials (Li4Ti5O12 anode and LiMn2O4 cathode) are presented as well as first results on sodium extraction from a layered SIB cathode material (Na0.84Fe0.56Mn0.44O2).

  2. An electrochemical cell for in operando studies of lithium/sodium batteries using a conventional x-ray powder diffractometer.

    PubMed

    Shen, Yanbin; Pedersen, Erik E; Christensen, Mogens; Iversen, Bo B

    2014-10-01

    An electrochemical cell has been designed for powder X-ray diffraction studies of lithium ion batteries (LIB) and sodium ion batteries (SIB) in operando with high time resolution using a conventional powder X-ray diffractometer. The cell allows for studies of both anode and cathode electrode materials in reflection mode. The cell design closely mimics that of standard battery testing coin cells and allows obtaining powder X-ray diffraction patterns under representative electrochemical conditions. In addition, the cell uses graphite as the X-ray window instead of beryllium, and it is easy to operate and maintain. Test examples on lithium insertion/extraction in two spinel-type LIB electrode materials (Li4Ti5O12 anode and LiMn2O4 cathode) are presented as well as first results on sodium extraction from a layered SIB cathode material (Na0.84Fe0.56Mn0.44O2). PMID:25362421

  3. Concentration of carbon dioxide by a high-temperature electrochemical membrane cell

    NASA Technical Reports Server (NTRS)

    Kang, M. P.; Winnick, J.

    1985-01-01

    The performance of a molten carbonate carbon dioxide concentrator (MCCDC) cell, as a device for removal of CO2 from manned spacecraft cabins without fuel expenditure, is investigated. The test system consists of an electrochemical cell (with an Li2CO3-38 mol pct K2CO3 membrane contained in a LiAlO2 matrix), a furnace, and a flow IR analyzer for monitoring CO2. Operation of the MCCDC-driven cell was found to be suitable for the task of CO2 removal: the cell performed at extremely low CO2 partial pressures (at or above 0.1 mm Hg); cathode CO2 efficiencies of 97 percent were achieved with 0.25 CO2 inlet concentration at 19 mA sq cm, at temperatures near 873 K. Anode concentrations of up to 5.8 percent were obtained. Simple cathode and anode performance equations applied to correlate cell performance agreed well with those measured experimentally. A flow diagram for the process is included.

  4. Electrochemical performance and transport properties of a Nafion membrane in a hydrogen-bromine cell environment

    NASA Technical Reports Server (NTRS)

    Baldwin, Richard S.

    1987-01-01

    The overall energy conversion efficiency of a hydrogen-bromine energy storage system is highly dependent upon the characteristics and performance of the ion-exchange membrane utilized as a half-cell separator. The electrochemical performance and transport properties of a duPont Nafion membrane in an aqueous HBr-Br2 environment were investigated. Membrane conductivity data are presented as a function of HBr concentration and temperature for the determination of ohmic voltage losses across the membrane in an operational cell. Diffusion-controlled bromine permeation rates and permeabilities are presented as functions of solution composition and temperature. Relationships between the degree of membrane hydration and the membrane transport characteristics are discussed. The solution chemistry of an operational hydrogen-bromine cell undergoing charge from 45% HBr to 5% HBr is discussed, and, based upon the experimentally observed bromine permeation behavior, predicted cell coulombic losses due to bromine diffusion through the membrane are presented as a function of the cell state-of-charge.

  5. Glucose and Lactate Biosensors for Scanning Electrochemical Microscopy Imaging of Single Live Cells

    PubMed Central

    Ciobanu, Madalina; Taylor, Dale E.; Wilburn, Jeremy P.; Cliffel, David E.

    2010-01-01

    We have developed glucose and lactate ultramicroelectrode (UME) biosensors based on glucose oxidase and lactate oxidase (with enzymes immobilized onto Pt UMEs by either electropolymerization or casting) for scanning electrochemical microscopy (SECM), and have determined their sensitivity to glucose and lactate, respectively. The results of our evaluations reveal different advantages for sensors constructed by each method: improved sensitivity and shorter manufacturing time for hand-casting, and increased reproducibility for electropolymerization. We have acquired amperometric approach curves (ACs) for each type of manufactured biosensor UME, and these ACs can be used as a means of positioning the UME above a substrate at a known distance. We have used the glucose biosensor UMEs to record profiles of glucose uptake above individual fibroblasts. Likewise, we have employed the lactate biosensor UMEs for recording the lactate production above single cancer cells with the SECM. We also show that oxygen respiration profiles for single cancer cells do not mimic cell topography, but are rather more convoluted, with a higher respiration activity observed at the points where the cell touches the Petri dish. These UME biosensors, along with the application of others already described in the literature, could prove to be powerful tools for mapping metabolic analytes, such as glucose, lactate and oxygen, in single cancer cells. PMID:18345647

  6. Design and testing of a packaged microfluidic cell for the multiplexed electrochemical detection of cancer markers.

    PubMed

    Henry, Olivier Yves; Fragoso, Alex; Beni, Valerio; Laboria, Noemi; Sánchez, Josep Lluis Acero; Latta, Daniel; Von Germar, Frithoj; Drese, Klaus; Katakis, Ioanis; O'Sullivan, Ciara Kathleen

    2009-10-01

    We present the rapid prototyping of electrochemical sensor arrays integrated to microfluidics towards the fabrication of integrated microsystems prototypes for point-of-care diagnostics. Rapid prototyping of microfluidics was realised by high-precision milling of polycarbonate sheets, which offers flexibility and rapid turnover of the desired designs. On the other hand, the electrochemical sensor arrays were fabricated using standard photolithographic and metal (gold and silver) deposition technology in order to realise three-electrode cells comprising gold counter and working electrodes as well as silver reference electrode. The integration of fluidic chips and electrode arrays was realised via a laser-machined double-sided adhesive gasket that allowed creating the microchannels necessary for sample and reagent delivery. We focused our attention on the reproducibility of the electrode array preparation for the multiplexed detection of tumour markers such as carcinoembryonic antigen and prostate-specific antigen as well as genetic breast cancer markers such as estrogen receptor-alpha, plasminogen activator urokinase receptor, epidermal growth factor receptor and erythroblastic leukemia viral oncogene homolog 2. We showed that by carefully controlling the electrode surface pre-treatment and derivatisation via thiolated antibodies or short DNA probes that the detection of several key health parameters on a single chip was achievable with excellent reproducibility and high sensitivity. PMID:19739140

  7. Electrodeposition and Screening of Photoelectrochemical Activity in Conjugated Polymers Using Scanning Electrochemical Cell Microscopy.

    PubMed

    Aaronson, Barak D B; Garoz-Ruiz, Jesus; Byers, Joshua C; Colina, Alvaro; Unwin, Patrick R

    2015-11-24

    A number of renewable energy systems require an understanding and correlation of material properties and photoelectrochemical activity on the micro to nanoscale. Among these, conducting polymer electrodes continue to be important materials. In this contribution, an ultrasensitive scanning electrochemical cell microscopy (SECCM) platform is used to electrodeposit microscale thin films of poly(3-hexylthiophene) (P3HT) on an optically transparent gold electrode and to correlate the morphology (film thickness and structural order) with photoactivity. The electrochemical growth of P3HT begins with a thin ordered film up to 10 nm thick, after which a second more disordered film is deposited, as revealed by micro-Raman spectroscopy. A decrease in photoactivity for the thicker films, measured in situ immediately following film deposition, is attributed to an increase in bulk film disorder that limits charge transport. Higher resolution ex situ SECCM phototransient measurements, using a smaller diameter probe, show local variations in photoactivity within a given deposit. Even after aging, thinner, more ordered regions within a deposit exhibit sustained enhanced photocurrent densities compared to areas where the film is thicker and more disordered. The platform opens up new possibilities for high-throughput combinatorial correlation studies, by allowing materials fabrication and high spatial resolution probing of processes in photoelectrochemical materials. PMID:26502089

  8. Electrochemical differential photoacoustic cell to study in situ the growing process of porous materials

    NASA Astrophysics Data System (ADS)

    Gutiérrez, Adriana; Giraldo, Jairo; Velázquez-Hernández, Rubén; Mendoza-López, Maria Luisa; Espinosa-Arbeláez, Diego G.; del Real, Alicia; Rodríguez-García, Mario E.

    2010-01-01

    In order to study in situ the growing process of porous materials, a new electrochemical differential photoacoustic cell (DPC) was developed. This system allows to obtain the thermal signals coming from the growing process of the pores without the external noise component. The DPC is a good system to growth porous silicon and study their growing process with reproducibility. The porous silicon samples were obtained by using electrochemical etching of (100) n-type silicon wafers with different nominal resistivity values in the range of 1-25 ? cm. The samples were formed in a solution of hydrofluoric acid and ethanol having a composition ratio of 1:1 in volume with etching voltage of 10V and an etching time of 2 min using back illumination provided by a laser beam with a wavelength of 808 nm. The porous samples were characterized by means of Raman microscopy, x-ray diffraction, and scanning electron microscopy. The crystallite sizes of the samples were obtained through the analysis of the micro-Raman spectra using a phonon confinement model, and the analysis of the x-ray diffractograms.

  9. Electrochemical cell and electrode designs for high-temperature/high-pressure kinetic measurements

    SciTech Connect

    Nagy, Z.; Yonco, R.M.

    1987-05-01

    Many corrosion processes of interest to the nuclear power industry occur in high-temperature/high-pressure aqueous systems. The investigation of the kinetics of the appropriate electrode reactions is a serious experimental challenge, partially because of the high temperatures and pressures and partially because many of these reactions are very rapid, requiring fast relaxation measurements. An electrochemical measuring system is described which is suitable for measurements of the kinetics of fast electrode reactions at temperatures extending to at least 300C and pressures to at least 10 MPa (100 atmospheres). The system includes solution preparation and handling equipment, the electrochemical cell, and several electrode designs. One of the new designs is a coaxial working electrode-counter electrode assembly; this electrode can be used with very fast-rising pulses, and it provides a well defined, repeatedly-polishable working surface. Low-impedance reference electrodes are also described, based on electrode concepts responding to the pH or the redox potential of the test solution. Additionally, a novel, long-life primary reference electrode design is reported, based on a modification of the external, pressure-balanced Ag/AgCl reference electrode.

  10. Photophysical and electrochemical properties, and molecular structures of organic dyes for dye-sensitized solar cells.

    PubMed

    Ooyama, Yousuke; Harima, Yutaka

    2012-12-21

    Dye-sensitized solar cells (DSSCs) based on organic dyes adsorbed on oxide semiconductor electrodes, such as TiO(2), ZnO, or NiO, which have emerged as a new generation of sustainable photovoltaic devices, have attracted much attention from chemists, physicists, and engineers because of enormous scientific interest in not only their construction and operational principles, but also in their high incident-solar-light-to-electricity conversion efficiency and low cost of production. To develop high-performance DSSCs, it is important to create efficient organic dye sensitizers, which should be optimized for the photophysical and electrochemical properties of the dyes themselves, with molecular structures that provide good light-harvesting features, good electron communication between the dye and semiconductor electrode and between the dye and electrolyte, and to control the molecular orientation and arrangement of the dyes on a semiconductor surface. The aim of this Review is not to make a list of a number of organic dye sensitizers developed so far, but to provide a new direction in the epoch-making molecular design of organic dyes for high photovoltaic performance and long-term stability of DSSCs, based on the accumulated knowledge of their photophysical and electrochemical properties, and molecular structures of the organic dye sensitizers developed so far. PMID:22807392

  11. On-site applicability of hydrogen peroxide producing microbial electrochemical cells (MECs) coupled with UV in wastewater disinfection study

    EPA Science Inventory

    Background: There is an increased interest in the application of microbial electrochemical cell (MEC) for the recovery of value-added products such as hydrogen gas and hydrogen peroxide (H2O2) from wastewater. H2O2 has strong oxidation capability and produces hydroxyl radicals wh...

  12. Boosting the voltage of a salinity-gradient-power electrochemical cell by means of complex-forming solutions

    E-print Network

    Carati, Andrea

    with respect to other well-known techniques that work quasi-reversibly, such as reverse electrodialysis luminance decay and voltage drift in polymer light-emitting electrochemical cells: Forward bias vs. reverse is significantly higher than the voltage obtained with the other quasi-reversible techniques. We show

  13. Hybrid organic-inorganic light-emitting electrochemical cells using fluorescent polymer and ionic liquid blend as an active layer

    NASA Astrophysics Data System (ADS)

    Lee, Hyun Jung; Lee, Bo Ram; Park, Ji Sun; Kim, Sang Ouk; Kim, Jin Young; Song, Myoung Hoon

    2011-06-01

    We demonstrate enhanced device performance by using a blend of emissive polymer and mobile ionic liquid molecules in hybrid organic-inorganic polymeric light-emitting electrochemical cells with high air stability. The mobile anions and cations redistributed near each electrode/active layer interface make ohmic contacts, thereby enhancing current density and electroluminescence efficiency at relatively low operating voltage.

  14. Syntrophic interactions between H2-scavenging and anode-respiring bacteria can improve current density in microbial electrochemical cells

    EPA Science Inventory

    High current density of 10.0-14.6 A/m2 and COD removal up to 96% were obtained in a microbial electrochemical cell (MEC) fed with digestate at hydraulic retention time (HRT) of 4d and 8d. Volatile fatty acids became undetectable in MEC effluent (HRT 8d), except for trivial acetat...

  15. Electrochemical gas-electricity cogeneration through direct carbon solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Xie, Yongmin; Cai, Weizi; Xiao, Jie; Tang, Yubao; Liu, Jiang; Liu, Meilin

    2015-03-01

    Solid oxide fuel cells (SOFCs), with yttrium stabilized zirconia (YSZ) as electrolyte, composite of strontium-doped lanthanum manganate (LSM) and YSZ as cathode, and cermet of silver and gadolinium-doped ceria (GDC) as anode, are prepared and tested with 5wt% Fe-loaded activated carbon as fuel and ambient air as oxidant. It is found that electricity and CO gas can be cogenerated in the direct carbon SOFCs through the electrochemical oxidation of CO and the Boudouard reaction. The gas-electricity cogeneration performances are investigated by taking the operating time of the DC-SOFCs as a measure of rate decrease of the Boudouard reaction. Three single cells and a two-cell-stack are tested and characterized in terms of electrical power output, CO production rate, electrical conversion efficiency, and overall conversion efficiency. It turns out that a rapid rate of the Boudouard reaction is necessary for getting high electrical power and CO production. Taking the emitted CO as part of the power output, an overall efficiency of 76.5% for the single cell, and of 72.5% for the stack, is obtained.

  16. Probing the chemistry of nickel/metal hydride battery cells using electrochemical impedance spectroscopy

    NASA Technical Reports Server (NTRS)

    Isaac, Bryan J.

    1994-01-01

    Electrochemical Impedance Spectroscopy (EIS) is a valuable tool for investigating the chemical and physical processes occurring at electrode surfaces. It offers information about electron transfer at interfaces, kinetics of reactions, and diffusion characteristics of the bulk phase between the electrodes. For battery cells, this technique offers another advantage in that it can be done without taking the battery apart. This non-destructive analysis technique can thus be used to gain a better understanding of the processes occurring within a battery cell. This also raises the possibility of improvements in battery design and identification or prediction of battery characteristics useful in industry and aerospace applications. EIS as a technique is powerful and capable of yielding significant information about the cell, but it also requires that the many parameters under investigation can be resolved. This implies an understanding of the processes occurring in a battery cell. Many battery types were surveyed in this work, but the main emphasis was on nickel/metal hydride batteries.

  17. Membraneless microfluidic microbial fuel cell for rapid detection of electrochemical activity of microorganism.

    PubMed

    Wang, Hsiang-Yu; Su, Jian-Yu

    2013-10-01

    A membraneless microfluidic microbial fuel cell (?MFC) for rapid detection of microorganism electroactivity is demonstrated in this study. Owing to the merit of laminar flow, the proposed ?MFC has well-separated anode and cathode without applying proton exchange membrane. The highest open circuit voltages (OCVs) produced by different anodal solutions: fresh medium, inactivated and untreated microflora, were 102, 131, and 246 mV, respectively. These results show that the membraneless ?MFC is capable of identifying the electric potential resulting from the imbalanced compositions between two streams (29 mV) and from the electrochemical activity of microflora (115 mV). When samples obtained along a batch cycle of H-type MFC were tested, the membraneless ?MFC produced similar OCVs with those from the H-type MFC. In conclusion, the proposed ?MFC has comparable abilities in detecting electroactivity with the conventional H-type MFC; moreover, it can distinguish the source of collected electricity. PMID:23415944

  18. Electrochemically Reduced Graphene Oxide Multilayer Films as Efficient Counter Electrode for Dye-Sensitized Solar Cells

    PubMed Central

    Xu, Xiaobao; Huang, Dekang; Cao, Kun; Wang, Mingkui; Zakeeruddin, Shaik M.; Grätzel, Michael

    2013-01-01

    We report on a new counter electrode for dye-sensitized solar cells (DSCs), which is prepared using layer-by-layer assembly of negatively charged graphene oxide and positively charged poly (diallyldimethylammonium chloride) followed by an electrochemical reduction procedure. The DSC devises using the heteroleptic Ru complex C106TBA as sensitizer and this new counter electrode reach power conversion efficiencies of 9.5% and 7.6% in conjunction with low volatility and solvent free ionic liquid electrolytes, respectively. The new counter electrode exhibits good durability (60°C for 1000?h in a solar simulator, 100?mW cm?2) during the accelerated tests when used in combination with an ionic liquid electrolyte. This work identifies a new class of electro-catalysts with potential for low cost photovoltaic devices. PMID:23508212

  19. Parallel macromolecular delivery and biochemical/electrochemical interface to cells employing nanostructures

    DOEpatents

    McKnight, Timothy E; Melechko, Anatoli V; Griffin, Guy D; Guillorn, Michael A; Merkulov, Vladimir L; Simpson, Michael L

    2015-03-31

    Systems and methods are described for parallel macromolecular delivery and biochemical/electrochemical interface to whole cells employing carbon nanostructures including nanofibers and nanotubes. A method includes providing a first material on at least a first portion of a first surface of a first tip of a first elongated carbon nanostructure; providing a second material on at least a second portion of a second surface of a second tip of a second elongated carbon nanostructure, the second elongated carbon nanostructure coupled to, and substantially parallel to, the first elongated carbon nanostructure; and penetrating a boundary of a biological sample with at least one member selected from the group consisting of the first tip and the second tip.

  20. SOLID OXIDE FUEL CELL CATHODES: Polarization Mechanisms and Modeling of the Electrochemical Performance

    NASA Astrophysics Data System (ADS)

    Fleig, Jurgen

    2003-08-01

    Several recent experimental and numerical investigations have contributed to the improved understanding of the electrochemical mechanisms taking place at solid oxide fuel cell (SOFC) cathodes and yielded valuable information on the relationships between alterable parameters (geometry/material) and the cathodic polarization resistance. Efforts to reduce the polarization resistance in SOFCs can benefit from these results, and some important aspects of the corresponding studies are reviewed. Experimental results, particularly measurements using geometrically well-defined Sr-doped LaMnO3 (LSM) cathodes, are discussed. In regard to simulations, the different levels of sophistication used in SOFC electrode modeling studies are summarized and compared. Exemplary simulations of mixed conducting cathodes that show the capabilities and limits of different modeling levels are described.

  1. Method of preparing porous, rigid ceramic separators for an electrochemical cell

    DOEpatents

    Bandyopadhyay, Gautam (Naperville, IL); Dusek, Joseph T. (Downers Grove, IL)

    1981-01-01

    Porous, rigid separators for electrochemical cells are prepared by first calcining particles of ceramic material at temperatures above about 1200.degree. C. for a sufficient period of time to reduce the sinterability of the particles. A ceramic powder that has not been calcined is blended with the original powder to control the porosity of the completed separator. The ceramic blend is then pressed into a sheet of the desired shape and sintered at a temperature somewhat lower than the calcination temperature. Separator sheets of about 1 to 2.5 mm thickness and 30 to 70% porosity can be prepared by this technique. Ceramics such as yttria, magnesium oxide and magnesium-aluminum oxide have advantageously been used to form separators by this method.

  2. A colour-tunable, weavable fibre-shaped polymer light-emitting electrochemical cell

    NASA Astrophysics Data System (ADS)

    Zhang, Zhitao; Guo, Kunping; Li, Yiming; Li, Xueyi; Guan, Guozhen; Li, Houpu; Luo, Yongfeng; Zhao, Fangyuan; Zhang, Qi; Wei, Bin; Pei, Qibing; Peng, Huisheng

    2015-04-01

    The emergence of wearable electronics and optoelectronics requires the development of devices that are not only highly flexible but can also be woven into textiles to offer a truly integrated solution. Here, we report a colour-tunable, weavable fibre-shaped polymer light-emitting electrochemical cell (PLEC). The fibre-shaped PLEC is fabricated using all-solution-based processes that can be scaled up for practical applications. The design has a coaxial structure comprising a modified metal wire cathode and a conducting aligned carbon nanotube sheet anode, with an electroluminescent polymer layer sandwiched between them. The fibre shape offers unique and promising advantages. For example, the luminance is independent of viewing angle, the fibre-shaped PLEC can provide a variety of different and tunable colours, it is lightweight, flexible and wearable, and it can potentially be woven into light-emitting clothes for the creation of smart fabrics.

  3. Electrodes including a polyphosphazene cyclomatrix, methods of forming the electrodes, and related electrochemical cells

    DOEpatents

    Gering, Kevin L; Stewart, Frederick F; Wilson, Aaron D; Stone, Mark L

    2014-10-28

    An electrode comprising a polyphosphazene cyclomatrix and particles within pores of the polyphosphazene cyclomatrix. The polyphosphazene cyclomatrix comprises a plurality of phosphazene compounds and a plurality of cross-linkages. Each phosphazene compound of the plurality of phosphazene compounds comprises a plurality of phosphorus-nitrogen units, and at least one pendant group bonded to each phosphorus atom of the plurality of phosphorus-nitrogen units. Each phosphorus-nitrogen unit is bonded to an adjacent phosphorus-nitrogen unit. Each cross-linkage of the plurality of cross-linkages bonds at least one pendant group of one phosphazene compound of the plurality of phosphazene compounds with the at least one pendant group of another phosphazene compound of the plurality of phosphazene compounds. A method of forming a negative electrode and an electrochemical cell are also described.

  4. Multistep electrochemical deposition of hierarchical platinum alloy counter electrodes for dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Zhang, Junjun; Ma, Mingming; Tang, Qunwei; Yu, Liangmin

    2016-01-01

    The preferred platinum counter electrode (CE) has been a burden for commercialization of dye-sensitized solar cell (DSSC) due to high expense and chemical corrosion by liquid electrolyte. In the current study, we have successfully realized the multistep deposition of platinum alloy CEs including PtNi, PtFe, and PtCo for liquid-junction DSSC applications. The preliminary results demonstrate that the enhanced electrochemical activities are attributable to high charge-transfer ability and matching work functions of the PtM (M = Ni, Fe, Co) alloy CEs to redox potential of I-/I3- electrolyte. The resultant DSSCs yield impressive power conversion efficiencies of 8.65%, 7.48%, and 7.08% with PtNi, PtFe, and PtCo CEs, respectively. On behalf of the competitive reactions between transition metals with liquid electrolyte, the PtM alloy CEs display enhanced long-term stability.

  5. Electrochemical Investigation of a Microbial Solar Cell Reveals a Nonphotosynthetic Biocathode Catalyst

    PubMed Central

    Glaven, Richard H.; Wang, Zheng; Zhou, Jing; Vora, Gary J.; Tender, Leonard M.

    2013-01-01

    Microbial solar cells (MSCs) are microbial fuel cells (MFCs) that generate their own oxidant and/or fuel through photosynthetic reactions. Here, we present electrochemical analyses and biofilm 16S rRNA gene profiling of biocathodes of sediment/seawater-based MSCs inoculated from the biocathode of a previously described sediment/seawater-based MSC. Electrochemical analyses indicate that for these second-generation MSC biocathodes, catalytic activity diminishes over time if illumination is provided during growth, whereas it remains relatively stable if growth occurs in the dark. For both illuminated and dark MSC biocathodes, cyclic voltammetry reveals a catalytic-current–potential dependency consistent with heterogeneous electron transfer mediated by an insoluble microbial redox cofactor, which was conserved following enrichment of the dark MSC biocathode using a three-electrode configuration. 16S rRNA gene profiling showed Gammaproteobacteria, most closely related to Marinobacter spp., predominated in the enriched biocathode. The enriched biocathode biofilm is easily cultured on graphite cathodes, forms a multimicrobe-thick biofilm (up to 8.2 ?m), and does not lose catalytic activity after exchanges of the reactor medium. Moreover, the consortium can be grown on cathodes with only inorganic carbon provided as the carbon source, which may be exploited for proposed bioelectrochemical systems for electrosynthesis of organic carbon from carbon dioxide. These results support a scheme where two distinct communities of organisms develop within MSC biocathodes: one that is photosynthetically active and one that catalyzes reduction of O2 by the cathode, where the former partially inhibits the latter. The relationship between the two communities must be further explored to fully realize the potential for MSC applications. PMID:23603672

  6. In-situ Photoelectron Microspectroscopy and Imaging of Electrochemical Processes at the Electrodes of a Self-driven Cell

    PubMed Central

    Bozzini, Benedetto; Amati, Matteo; Gregoratti, Luca; Kiskinova, Maya

    2013-01-01

    The challenges in development of solid oxide fuel cells (SOFCs) are reducing their dimensions and increasing their efficiency and durability, which requires physicochemical characterization at micro-scales of the device components during operation conditions. Recently, the unique potential of scanning photoelectron microscopy (SPEM) has been demonstrated by in-situ studies of externally-driven SOFCs, which mimic real devices. Here we overcome the gap between model and real systems using a single-chamber Ni|YSZ|Mn SOFC, supporting a range of self-driven electrochemical reactions in variable gas environments and temperatures. The reported SPEM results, obtained during spontaneous electrochemical processes occurring in reactive gas ambient, demonstrate the chemical evolution of electrodic material, in particular the lateral distribution of the oxidation state and the induced local potential, clearly marking out the electrochemically most active micro-regions of the Ni anode. PMID:24092014

  7. Neutrophils and monocytes transport tumor cell antigens from the peritoneal cavity to secondary lymphoid tissues

    SciTech Connect

    Terasawa, Masao; Nagata, Kisaburo; Kobayashi, Yoshiro

    2008-12-12

    Antigen-transporting cells take up pathogens, and then migrate from sites of inflammation to secondary lymphoid tissues to induce an immune response. Among antigen-transporting cells, dendritic cells (DCs) are believed to be the most potent and professional antigen-presenting cells that can stimulate naive T cells. However, the cells that transport antigens, tumor cell antigens in particular, have not been clearly identified. In this study we have analyzed what types of cells transport tumor cell antigens to secondary lymphoid tissues. We show that neutrophils, monocytes and macrophages but not DCs engulf X-irradiated P388 leukemic cells after their injection into the peritoneal cavity, and that neutrophils and monocytes but not macrophages migrate to the parathymic lymph nodes (pLN), the blood, and then the spleen. The monocytes in the pLN comprise Gr-1{sup -} and Gr-1{sup +} ones, and some of these cells express CD11c. Overall, this study demonstrates that neutrophils and monocytes transport tumor cell antigens from the peritoneal cavity to secondary lymphoid tissues.

  8. A combined electrochemical and optical trapping platform for measuring single cell respiration rates at electrode interfaces.

    PubMed

    Gross, Benjamin J; El-Naggar, Mohamed Y

    2015-06-01

    Metal-reducing bacteria gain energy by extracellular electron transfer to external solids, such as naturally abundant minerals, which substitute for oxygen or the other common soluble electron acceptors of respiration. This process is one of the earliest forms of respiration on earth and has significant environmental and technological implications. By performing electron transfer to electrodes instead of minerals, these microbes can be used as biocatalysts for conversion of diverse chemical fuels to electricity. Understanding such a complex biotic-abiotic interaction necessitates the development of tools capable of probing extracellular electron transfer down to the level of single cells. Here, we describe an experimental platform for single cell respiration measurements. The design integrates an infrared optical trap, perfusion chamber, and lithographically fabricated electrochemical chips containing potentiostatically controlled transparent indium tin oxide microelectrodes. Individual bacteria are manipulated using the optical trap and placed on the microelectrodes, which are biased at a suitable oxidizing potential in the absence of any chemical electron acceptor. The potentiostat is used to detect the respiration current correlated with cell-electrode contact. We demonstrate the system with single cell measurements of the dissimilatory-metal reducing bacterium Shewanella oneidensis MR-1, which resulted in respiration currents ranging from 15 fA to 100 fA per cell under our measurement conditions. Mutants lacking the outer-membrane cytochromes necessary for extracellular respiration did not result in any measurable current output upon contact. In addition to the application for extracellular electron transfer studies, the ability to electronically measure cell-specific respiration rates may provide answers for a variety of fundamental microbial physiology questions. PMID:26133851

  9. A combined electrochemical and optical trapping platform for measuring single cell respiration rates at electrode interfaces

    NASA Astrophysics Data System (ADS)

    Gross, Benjamin J.; El-Naggar, Mohamed Y.

    2015-06-01

    Metal-reducing bacteria gain energy by extracellular electron transfer to external solids, such as naturally abundant minerals, which substitute for oxygen or the other common soluble electron acceptors of respiration. This process is one of the earliest forms of respiration on earth and has significant environmental and technological implications. By performing electron transfer to electrodes instead of minerals, these microbes can be used as biocatalysts for conversion of diverse chemical fuels to electricity. Understanding such a complex biotic-abiotic interaction necessitates the development of tools capable of probing extracellular electron transfer down to the level of single cells. Here, we describe an experimental platform for single cell respiration measurements. The design integrates an infrared optical trap, perfusion chamber, and lithographically fabricated electrochemical chips containing potentiostatically controlled transparent indium tin oxide microelectrodes. Individual bacteria are manipulated using the optical trap and placed on the microelectrodes, which are biased at a suitable oxidizing potential in the absence of any chemical electron acceptor. The potentiostat is used to detect the respiration current correlated with cell-electrode contact. We demonstrate the system with single cell measurements of the dissimilatory-metal reducing bacterium Shewanella oneidensis MR-1, which resulted in respiration currents ranging from 15 fA to 100 fA per cell under our measurement conditions. Mutants lacking the outer-membrane cytochromes necessary for extracellular respiration did not result in any measurable current output upon contact. In addition to the application for extracellular electron transfer studies, the ability to electronically measure cell-specific respiration rates may provide answers for a variety of fundamental microbial physiology questions.

  10. Ageing combines CD4 T cell lymphopenia in secondary lymphoid organs and T cell accumulation in gut associated lymphoid tissue

    PubMed Central

    2014-01-01

    Background CD4 T cell lymphopenia is an important T cell defect associated to ageing. Higher susceptibility to infections, cancer, or autoimmune pathologies described in aged individuals is thought to partly rely on T cell lymphopenia. We hypothesize that such diverse effects may reflect anatomical heterogeneity of age related T cell lymphopenia. Indeed, no data are currently available on the impact of ageing on T cell pool recovered from gut associated lymphoid tissue (GALT), a crucial site of CD4 T cell accumulation. Results Primary, secondary and tertiary lymphoid organs of C57BL/6 animals were analysed at three intervals of ages: 2 to 6 months (young), 10 to 14 months (middle-aged) and 22 to 26 months (old). We confirmed that ageing preferentially impacted CD4 T cell compartment in secondary lymphoid organs. Importantly, a different picture emerged from gut associated mucosal sites: during ageing, CD4 T cell accumulation was progressively developing in colon and small intestine lamina propria and Peyer’s patches. Similar trend was also observed in middle-aged SJL/B6 F1 mice. Interestingly, an inverse correlation was detected between CD4 T cell numbers in secondary lymphoid organs and colonic lamina propria of C57BL/6 mice whereas no increase in proliferation rate of GALT CD4 T cells was detected. In contrast to GALT, no CD4 T cell accumulation was detected in lungs and liver in middle-aged animals. Finally, the concomitant accumulation of CD4 T cell in GALT and depletion in secondary lymphoid organs during ageing was detected both in male and female animals. Conclusions Our data thus demonstrate that T cell lymphopenia in secondary lymphoid organs currently associated to ageing is not sustained in gut or lung mucosa associated lymphoid tissues or non-lymphoid sites such as the liver. The inverse correlation between CD4 T cell numbers in secondary lymphoid organs and colonic lamina propria and the absence of overt proliferation in GALT suggest that marked CD4 T cell decay in secondary lymphoid organs during ageing reflect redistribution of CD4 T cells rather than generalized CD4 T cell decay. Such anatomical heterogeneity may provide an important rationale for the diversity of immune defects observed during ageing. PMID:24829607

  11. Electrochemical properties of aryladamantanes as new overcharge protection compounds for lithium cells

    NASA Astrophysics Data System (ADS)

    Watanabe, Yuu; Morimoto, Hideyuki; Tobishima, Shin-ichi

    The development of new overcharge protection compounds for 4 V-class lithium cells with LiCoO 2 cathodes was attempted in order to protect the cells from the hazards of ignition and/or explosion when overcharged. At least two requirements must be met as regards overcharge protection compounds. They must have an oxidation potential ( Eox) in the 4.6-4.8 V range versus Li/Li + and they must not adversely influence the lithium cycling efficiency (Eff). The overcharge protection compounds were used by adding them to the electrolyte solution, which was LiClO 4/propylene carbonate. First, this study involved a basic examination of the relationships among the Eox values of arenes including polyacenes, naphthalene derivatives and methylbenzenes, their chemical structure, the aromatic ring size and the effects of substituent functional groups. Next, the Eox and Eff values of cycloalkanes including cyclohexane, decaline, adamantane and norbornane were examined. Based on these examination results, various adamantane derivatives were synthesized and their electrochemical properties were investigated. Finally, four aryladamantanes (1-( p-tolyl)adamantane, 1-( m-tolyl)adamantane, 1-( o-tolyl)adamantane, 1-(4-ethylphenyl)adamantane) were found to exhibit better Eox and Eff values than those of biphenyl, which is already used in commercial cells as an overcharge protection additive.

  12. Effects of Operating Conditions on Internal Resistances in Enzyme Fuel Cells Studied via Electrochemical Impedance Spectroscopy

    SciTech Connect

    Aaron, D; Borole, Abhijeet P; Yiacoumi, Sotira; Tsouris, Costas

    2012-01-01

    Enzyme fuel cells (EFCs) offer some advantages over traditional precious-metal-catalyzed fuel cells, such as polymer electrolyte membrane fuel cells (PEMFCs). However, EFCs exhibit far less power output than PEMFCs and have relatively short life spans before materials must be replaced. In this work, electrochemical impedance spectroscopy (EIS) is used to analyze the internal resistances throughout the EFC at a variety of operating conditions. EIS analysis is focused primarily on the resistances of the anode, solution/membrane, and cathode. Increased enzyme loading results in improved power output and reductions in internal resistance. Conditions are identified for which enzyme loading does not limit the EFC performance. EIS experiments are also reported for EFCs operated continuously for 2 days; power output declines sharply over time, while all internal resistances increase. Drying of the cathode and enzyme/mediator degradation are believed to have contributed to this behavior. Finally, experiments are performed at varying air-humidification temperatures. Little effect on internal resistances or power output is observed. However, it is anticipated that increased air humidification can improve longevity by delivering more water to the cathode. Improvements to the enzymatic cathode are needed for EFC development. These improvements need to focus on improving transport rather than increasing enzyme loading.

  13. Electrochemical detection of catecholamine release using planar iridium oxide electrodes in nanoliter microfluidic cell culture volumes.

    PubMed

    Ges, Igor A; Currie, Kevin P M; Baudenbacher, Franz

    2012-04-15

    Release of neurotransmitters and hormones by calcium regulated exocytosis is a fundamental cellular/molecular process that is disrupted in a variety of psychiatric, neurological, and endocrine disorders. Therefore, this area represents a relevant target for drug and therapeutic development, efforts that will be aided by novel analytical tools and devices that provide mechanistically rich data with increased throughput. Toward this goal, we have electrochemically deposited iridium oxide (IrOx) films onto planar thin film platinum electrodes (20 ?m×300 ?m) and utilized these for quantitative detection of catecholamine release from adrenal chromaffin cells trapped in a microfluidic network. The IrOx electrodes show a linear response to norepinephrine in the range of 0-400 ?M, with a sensitivity of 23.1±0.5 mA/M mm(2). The sensitivity of the IrOx electrodes does not change in the presence of ascorbic acid, a substance commonly found in biological samples. A replica molded polydimethylsiloxane (PDMS) microfluidic device with nanoliter sensing volumes was aligned and sealed to a glass substrate with the sensing electrodes. Small populations of chromaffin cells were trapped in the microfluidic device and stimulated by rapid perfusion with high potassium (50mM) containing Tyrode's solution at a flow rate of 1 nL/s. Stimulation of the cells produced a rapid increase in current due to oxidation of the released catecholamines, with an estimated maximum concentration in the cell culture volume of ~52 ?M. Thus, we demonstrate the utility of an integrated microfluidic network with IrOx electrodes for real-time quantitative detection of catecholamines released from small populations of chromaffin cells. PMID:22398270

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

    DOEpatents

    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)

    1994-01-01

    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.

  15. Risk of secondary solid malignancies after allogeneic hematopoietic stem cell transplantation and preventive strategies.

    PubMed

    Adhikari, Janak; Sharma, Priyadarshani; Bhatt, Vijaya Raj

    2015-12-01

    The risk of secondary solid malignancies is increased after allogeneic hematopoietic stem cell transplantation (HSCT). The risk starts at about 10 years after HSCT and continues even 20 years later. The most common secondary malignancies include squamous cell carcinoma of skin, genitourinary tract and oral cavity; lung and breast cancers. The use of total body irradiation or conditioning chemotherapy, chronic graft-versus-host disease and duration since HSCT can influence the risk of secondary solid malignancies. Secondary solid malignancies are common causes of nonrelapse mortality in long-term survivors and may account for up to 10% of late deaths. Avoiding smoking, alcohol use and excess sun exposure may reduce the risk. Cancer prevention guidelines are largely consensus-driven and follow the recommendations for general population. PMID:26551415

  16. Secondary cell-mediated lympholysis: importance of H-2 LD and SD factors

    PubMed Central

    1976-01-01

    Lymphocytes stimulated in mixed leukocyte cultures and left for 13-17 days, i.e. beyond their peak proliferative and cytotoxic reactivities, can be restimulated to give a secondary-type rapid and strong proliferative and cytotoxic response when confronted with cells of the original sensitizing cell donor. We have concerned ourselves primarily with the requirements of restimulation for the presence of LD and/or SD stimuli on the restimulating cells. (a) The low level cell-mediated lympholysis (CML) associated with LD differences in a primary CML can be restimulated to give a secondary-type response by those same LD antigens. (b) If the original sensitizing cells differ from the responding cells by both LD and SD antigens, restimulation with only the LD antigens, or third-party cells presumably carrying cross- reactive LD antigens, can restimulate the secondary CML responses directed against the SD antigens on the original sensitizing cells. (c) The presence of SD antigens on the restimulating cells that are cross- reactive with the primary sensitizing SD antigens (as determined in a primary CML) leads to the preferential activation of cytotoxic T lymphocytes reactive to those antigens although maximum cytotoxicity is still directed at cells carrying the original sensitizing SD antigens. A model to explain these results is presented. PMID:131173

  17. Electrochemical assay of ?-glucosidase activity and the inhibitor screening in cell medium.

    PubMed

    Zhang, Juan; Liu, Ying; Wang, Xiaonan; Chen, Yangyang; Li, Genxi

    2015-12-15

    An electrochemical method is established in this work for the assay of ?-glucosidase activity and the inhibitor screening through one-step displacement reaction, which can be directly used in cell medium. The displacement reaction can be achieved via strong binding of 4-aminophenyl-?-D-glucopyranoside (pAPG)/magnetic nanoparticles (MNPs) to pyrene boric acid (PBA) immobilized on the surface of graphite electrode (GE), compared to that of dopamine (DA)/sliver nanoparticles (AgNPs). Since ?-glucosidase can specifically catalyze MNPs/pAPG into MNPs/pAP which has no binding capacity with PBA, the activity of both isolated and membrane bound enzyme can be well evaluated by using this proposed method. Meanwhile, signal amplification can be accomplished via the immobilization of DA at the outer layer of AgNPs, and the accuracy can be strengthened through magnetic separation. Moreover, this method can also be utilized for inhibitor screening not only in the medium containing the enzyme but also in cell medium. With good precision and accuracy, it may be extended to other proteases and their inhibitors as well. PMID:26201984

  18. Direct two-dimensional electrochemical impedance spectra simulation for solid oxide fuel cell

    NASA Astrophysics Data System (ADS)

    Shi, Yixiang; Wang, Hongjian; Cai, Ningsheng

    2012-06-01

    A two-dimensional (2D) EIS simulation approach is developed by solving a SOFC unit cell model with imposed sinusoidal voltage perturbations at different frequencies. The transient SOFC unit cell model describes the intricate interdependency among the ionic/electronic conduction, multi-component species transport, electrochemical reaction processes and electrode microstructure as well as the coupling processes of mass, energy, momentum transport within flow channels. The model calculates the local transient response and impedance spectra as a function of channel position. The effects of the reaction depletion, product accumulation as well as the temperature variation along the flow channels on the EIS spectra are numerically simulated with a counter-flow mode. The results show that the convection-diffusion process along the flow channel has significant effects on the low frequency half circle of the impedance spectra. The temperature oscillations accumulate along the flow channels, and then affect the current responses which probably lead to an electro-thermal impedance effects.

  19. Non-isothermal electrochemical model for lithium-ion cells with composite cathodes

    NASA Astrophysics Data System (ADS)

    Basu, Suman; Patil, Rajkumar S.; Ramachandran, Sanoop; Hariharan, Krishnan S.; Kolake, Subramanya Mayya; Song, Taewon; Oh, Dukjin; Yeo, Taejung; Doo, Seokgwang

    2015-06-01

    Transition metal oxide cathodes for Li-ion batteries offer high energy density and high voltage. Composites of these materials have shown excellent life expectancy and improved thermal performance. In the present work, a comprehensive non-isothermal electrochemical model for a Lithium ion cell with a composite cathode is developed. The present work builds on lithium concentration-dependent diffusivity and thermal gradient of cathode potential, obtained from experiments. The model validation is performed for a wide range of temperature and discharge rates. Excellent agreement is found for high and room temperature with moderate success at low temperatures, which can be attributed to the low fidelity of material properties at low temperature. Although the cell operation is limited by electronic conductivity of NCA at room temperature, at low temperatures a shift in controlling process is seen, and operation is limited by electrolyte transport. At room temperature, the lithium transport in Cathode appears to be the main source of heat generation with entropic heat as the primary contributor at low discharge rates and ohmic heat at high discharge rates respectively. Improvement in electronic conductivity of the cathode is expected to improve the performance of these composite cathodes and pave way for its wider commercialization.

  20. Comprehensive forensic analyses of debris from the fatal explosion of a "cold fusion" electrochemical cell.

    PubMed

    Grant, P M; Whipple, R E; Andresen, B D

    1995-01-01

    Selected components of explosion debris from the SRI International incident of January 2, 1992 were subjected to forensic analyses to elucidate potential causes of, or contributing factors to, the explosion. Interrogation of the debris encompassed nuclear, chemical, physical, and materials investigations. Nuclear studies for the determination of tritium and neutron-activation products in stainless steel and brass were conducted. No evidence for signature species indicative of orthodox nuclear events was detected. The inorganic and particulate analyses were likewise negative with respect to residues of unexpected chemical species. Such target compounds included conventional explosives, accelerants, propellants, or any exceptional industrial chemicals. Materials characterization identified the type of stainless steel used in the manufacture of the electrolytic cell as one relatively high in Mo concentration, probably type 316. Metallurgical analyses of the cell vessel wall and its detached base provided no evidence of corrosion or hydrogen embrittlement, leaving only ductile failure of the weld as contributing to the incident. The weld was found to have missed the center-line of the step joint, and the average penetration of the weld was measured to be 54%. The GC-MS analyses of trace organic components in the explosion debris provided a most interesting result. Although no evidence of organic explosives, oxidizers, or other unusual compounds was detected, the presence of an organic oil in the interior of the electrochemical cell was established. It is likely that the source of this oil was lubricating fluid from machining the metal cell components.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7876799

  1. Capacity-cycle life behavior in secondary lithium cells

    NASA Technical Reports Server (NTRS)

    Somoano, R. B.; Carter, B. J.; Shen, D.; Yen, S. P. S.

    1985-01-01

    The practical utilization of high energy density rechargeable lithium cells is dependent upon maintaining high capacity for the duration of the required cycle life. However, a critical, yet generic problem with room temperature lithium systems is that the capacity often declines considerably during the early stages of cycling. The results of our studies are reported on electrolyte degradation which is observed after cells have undergone 300 and 700 deep cycles with 3-methylsulfolane- and 2-methyltetrahydrofuran-LiAsF6 electrolytes, respectively.

  2. CYCD3 D-type cyclins regulate cambial cell proliferation and secondary growth in Arabidopsis

    PubMed Central

    Collins, Carl; Maruthi, N. M.; Jahn, Courtney E.

    2015-01-01

    A major proportion of plant biomass is derived from the activity of the cambium, a lateral meristem responsible for vascular tissue formation and radial organ enlargement in a process termed secondary growth. In contrast to our relatively good understanding of the regulation of primary meristems, remarkably little is known concerning the mechanisms controlling secondary growth, particularly how cambial cell divisions are regulated and integrated with vascular differentiation. A genetic loss-of-function approach was used here to reveal a rate-limiting role for the Arabidopsis CYCLIN D3 (CYCD3) subgroup of cell-cycle genes in the control of cambial cell proliferation and secondary growth, providing conclusive evidence of a direct link between the cell cycle and vascular development. It is shown that all three CYCD3 genes are specifically expressed in the cambium throughout vascular development. Analysis of a triple loss-of-function CYCD3 mutant revealed a requirement for CYCD3 in promoting the cambial cell cycle since mutant stems and hypocotyls showed a marked reduction in diameter linked to reduced mitotic activity in the cambium. Conversely, loss of CYCD3 provoked an increase in xylem cell size and the expression of differentiation markers, showing that CYCD3 is required to restrain the differentiation of xylem precursor cells. Together, our data show that tight control of cambial cell division through developmental- and cell type-specific regulation of CYCD3 is required for normal vascular development, constituting part of a novel mechanism controlling organ growth in higher plants. PMID:26022252

  3. CYCD3 D-type cyclins regulate cambial cell proliferation and secondary growth in Arabidopsis.

    PubMed

    Collins, Carl; Maruthi, N M; Jahn, Courtney E

    2015-08-01

    A major proportion of plant biomass is derived from the activity of the cambium, a lateral meristem responsible for vascular tissue formation and radial organ enlargement in a process termed secondary growth. In contrast to our relatively good understanding of the regulation of primary meristems, remarkably little is known concerning the mechanisms controlling secondary growth, particularly how cambial cell divisions are regulated and integrated with vascular differentiation. A genetic loss-of-function approach was used here to reveal a rate-limiting role for the Arabidopsis CYCLIN D3 (CYCD3) subgroup of cell-cycle genes in the control of cambial cell proliferation and secondary growth, providing conclusive evidence of a direct link between the cell cycle and vascular development. It is shown that all three CYCD3 genes are specifically expressed in the cambium throughout vascular development. Analysis of a triple loss-of-function CYCD3 mutant revealed a requirement for CYCD3 in promoting the cambial cell cycle since mutant stems and hypocotyls showed a marked reduction in diameter linked to reduced mitotic activity in the cambium. Conversely, loss of CYCD3 provoked an increase in xylem cell size and the expression of differentiation markers, showing that CYCD3 is required to restrain the differentiation of xylem precursor cells. Together, our data show that tight control of cambial cell division through developmental- and cell type-specific regulation of CYCD3 is required for normal vascular development, constituting part of a novel mechanism controlling organ growth in higher plants. PMID:26022252

  4. Method and design for externally applied laser welding of internal connections in a high power electrochemical cell

    DOEpatents

    Martin, Charles E; Fontaine, Lucien; Gardner, William H

    2014-01-21

    An electrochemical cell includes components that are welded from an external source after the components are assembled in a cell canister. The cell canister houses electrode tabs and a core insert. An end cap insert is disposed opposite the core insert. An external weld source, such as a laser beam, is applied to the end cap insert, such that the end cap insert, the electrode tabs, and the core insert are electrically coupled by a weld which extends from the end cap insert to the core insert.

  5. More accurate macro-models of solid oxide fuel cells through electrochemical and microstructural parameter estimation - Part I: Experimentation

    NASA Astrophysics Data System (ADS)

    Boigues Muñoz, Carlos; Pumiglia, Davide; McPhail, Stephen J.; Montinaro, Dario; Comodi, Gabriele; Santori, Giulio; Carlini, Maurizio; Polonara, Fabio

    2015-10-01

    The distributed relaxation times (DRT) method has been employed in order to deconvolute the electrochemical impedance spectroscopy (EIS) measurements carried out on a Ni-YSZ|YSZ|Pr2NiO4+? - GDC solid oxide fuel cell (SOFC). This has enabled to shed light on the diverse physicochemical processes occurring within the aforementioned cell by individuating the characteristic relaxation times of these by means of a specifically designed experimental campaign where temperature and gas compositions in anode and cathode were varied one at a time. A comprehensive equivalent circuit model (ECM) has thus been generated based on the processes observed in the DRT spectra. This ECM has proved to be instrumental for the obtainment of parameters which describe the microstructural and electrochemical properties of the SOFC when used contemporaneously with experimental results and modelling theory (described in Part II of this work).

  6. Electrochemical study of lithiated transition metal oxide composite for single layer fuel cell

    NASA Astrophysics Data System (ADS)

    Hu, Huiqing; Lin, Qizhao; Muhammad, Afzal; Zhu, Bin

    2015-07-01

    This study analyzed the effect of various semiconductors of transition metal oxides in modified lithiated NiO on the electrochemical performance of a single layer fuel cell (SLFC). A typical ionic conductor Ce0.8Sm0.2O2-? (SDC) and three types of semiconductors Li0.3Ni0.6Cu0.07Sr0.03O2-? (LNCuS), Li0.3Ni0.6Mn0.07Sr0.03O2-? (LNMnS) and Li0.3Ni0.6Co0.07Sr0.03O2-? (LNCoS), were the fundamental components of the SLFCs. The components were characterized by using X-ray diffraction (XRD), a scanning electron microscope (SEM), and an energy-dispersive X-ray spectrometer (EDS). The stability of the synthesized materials was evaluated using thermal gravity analysis (TGA). The ohmic resistances at 500 °C were 0.36, 0.48 and 0.58 ? cm2 for 6SDC-4LNMnS, 6SDC-4LNCoS and 6SDC-4LNCuS, respectively. Among the three SLFCs, the single cell with 6SDC-4LNMnS achieves the highest power density (422 mW cm-2) but the lowest temperature stability, while the single cell with 6SDC-4LNCuS achieved the lowest power density (331 mW cm-2) but the highest temperature stability during the operation temperature.

  7. Evaluation program for secondary spacecraft cells: Cycle life test

    NASA Technical Reports Server (NTRS)

    Harkness, J. D.

    1979-01-01

    The service life and storage stability for several storage batteries were determined. The batteries included silver-zinc batteries, nickel-cadmium batteries, and silver-cadmium batteries. The cell performance characteristics and limitations are to be used by spacecraft power systems planners and designers. A statistical analysis of the life cycle prediction and cause of failure versus test conditions is presented.

  8. Electrochemical methane sensor

    DOEpatents

    Zaromb, S.; Otagawa, T.; Stetter, J.R.

    1984-08-27

    A method and instrument including an electrochemical cell for the detection and measurement of methane in a gas by the oxidation of methane electrochemically at a working electrode in a nonaqueous electrolyte at a voltage about 1.4 volts vs R.H.E. (the reversible hydrogen electrode potential in the same electrolyte), and the measurement of the electrical signal resulting from the electrochemical oxidation.

  9. ELECTRON TRANSPORT AND SECONDARY EMISSION IN A SURFACE OF SOLAR CELL P. Degond, R. Talaalout, M.-H. Vignal

    E-print Network

    Vignal, Marie-Hélène

    1 ELECTRON TRANSPORT AND SECONDARY EMISSION IN A SURFACE OF SOLAR CELL P. Degond, R. Talaalout, M of a primary discharge where electron secondary emission plays an important role. A schematic of a conventional secondary electron emission. Then the desorbed neutrals accumulate in the gap between the cov- erglass

  10. Exploratory cell research and fundamental processes study in solid state electrochemical cells: Final report

    SciTech Connect

    Smyrl, W.H.; Owens, B.B.; White, H.S.

    1988-10-01

    Effort was focused on 3 major areas: Exploratory Cell Research,Fundamental Studies of Reaction and Transport in Polymeric Electrolytes, and Voltammetry Studies using Microstructured Electrodes. Work includes design, fabrication and application. 38 figs., 7 tabs.

  11. Coupling of an enzymatic biofuel cell to an electrochemical cell for self-powered glucose sensing with optical readout.

    PubMed

    Pinyou, Piyanut; Conzuelo, Felipe; Sliozberg, Kirill; Vivekananthan, Jeevanthi; Contin, Andrea; Pöller, Sascha; Plumeré, Nicolas; Schuhmann, Wolfgang

    2015-12-01

    A miniaturized biofuel cell (BFC) is powering an electrolyser invoking a glucose concentration dependent formation of a dye which can be determined spectrophotometrically. This strategy enables instrument free analyte detection using the analyte-dependent BFC current for triggering an optical read-out system. A screen-printed electrode (SPE) was used for the immobilization of the enzymes glucose dehydrogenase (GDH) and bilirubin oxidase (BOD) for the biocatalytic oxidation of glucose and reduction of molecular oxygen, respectively. The miniaturized BFC was switched-on using small sample volumes (ca. 60 ?L) leading to an open-circuit voltage of 567 mV and a maximal power density of (6.8±0.6) ?W cm(-2). The BFC power was proportional to the glucose concentration in a range from 0.1 to 1.0 mM (R(2)=0.991). In order to verify the potential instrument-free analyte detection the BFC was directly connected to an electrochemical cell comprised of an optically-transparent SPE modified with methylene green (MG). The reduction of the electrochromic reporter compound invoked by the voltage and current flow applied by the BFC let to MG discoloration, thus allowing the detection of glucose. PMID:25892686

  12. Electrode for a rechargeable electrochemical cell and method and apparatus for making same

    SciTech Connect

    Pensabene, S.F.; West, J.K.; Leclair, R.A.; Conant, F.V.; Catotti, A.J.; Fralick, W.L.

    1987-08-11

    A process is described for manufacturing an electrode for a rechargeable electrochemical cell containing an electrolyte by electrodepositing a metal on the surface of a continuous metallic strip, the process comprising the steps of: providing an etchant tank containing an etchant for removing contaminants from the surface of the continuous metallic strip; passing the continuous metallic strip while negatively polarized through the etchant tank prior to passing the metallic strip through a first electrolytic bath to remove the contaminants on the surface of the metallic strip prior to the electrodeposition step; providing a first tank containing an electrolytic bath containing ions of the metal to be deposited; immersing in the first electrolytic bath a positively polarized electrode comprising the metal to be deposited on the metallic strip; negatively polarizing the metallic strip; passing the metallic strip while negatively polarized through the tank and through the first electrolytic bath to effect deposition of the metal on the metallic strip; providing a second tank containing a second electrolytic bath; immersing in the second electrolytic bath a second negatively polarized electrode; positively polarizing the metallic strip containing the deposited metal after emergence from the first tank, and passing the positively polarized metallic strip containing the deposited metal through the second electrolytic bath to effect oxidation of the deposited metal.

  13. White light-emitting electrochemical cells based on the Langmuir-Blodgett technique.

    PubMed

    Fernández-Hernández, Jesús M; De Cola, Luisa; Bolink, Henk J; Clemente-León, Miguel; Coronado, Eugenio; Forment-Aliaga, Alicia; López-Muñoz, Angel; Repetto, Diego

    2014-11-25

    Light-emitting electrochemical cells (LECs) showing a white emission have been prepared with Langmuir-Blodgett (LB) films of the metallosurfactant bis[2-(2,4-difluorophenyl)pyridine][2-(1-hexadecyl-1H-1,2,3-triazol-4-yl)pyridine]iridium(III) chloride (1), which work with an air-stable Al electrode. They were prepared by depositing a LB film of 1 on top of a layer of poly(N,N'-diphenyl-N,N'-bis(4-hexylphenyl)-[1,1'-biphenyl]-4,4'-diamine (pTPD) spin-coated on indium tin oxide (ITO). The white color of the electroluminescence of the device contrasts with the blue color of the photoluminescence of 1 in solution and within the LB films. Furthermore, the crystal structure of 1 is reported together with the preparation and characterization of the Langmuir monolayers (?-A compression isotherms and Brewster angle microscopy (BAM)) and LB films of 1 (IR, UV-vis and emission spectroscopy, X-ray photoelectron spectroscopy (XPS), specular X-ray reflectivity (SXR), and atomic force microscopy (AFM)). PMID:25347390

  14. Electrochemical investigation of stainless steel corrosion in a proton exchange membrane electrolyzer cell

    DOE PAGESBeta

    Mo, Jingke; Steen, Stuart M.; Zhang, Feng-Yuan; Toops, Todd J.; Brady, Michael P.; Green, Johney B.

    2015-08-05

    The lack of a fundamental understanding of the corrosion mechanisms in the electrochemical environments of proton exchange membrane (PEM) electrolyzer and/or fuel cells (ECs/FCs) has seriously hindered the improvement of performance and efficiency of PEM ECs/FCs. In this study, a stainless steel mesh was purposely used as an anode gas diffusion layer that was intentionally operated with high positive potentials under harsh oxidative environments in a PEMEC to study the corrosion mechanism of metal migration. A significant amount of iron and nickel cations were determined to transport through the anode catalyst layer, the PEM and the cathode catalyst layer duringmore »the PEMEC operation. The formation/deposition of iron oxide and nickel oxide on the carbon paper gas diffusion layer at the cathode side is first revealed by both scanning electron microscope and X-ray diffraction. The results indicate the corrosion elements of iron and nickel are transported from anode to cathode through the catalyst-coated membrane, and deposited on carbon fibers as oxides. This phenomenon could also open a new corrosion-based processing approach to potentially fabricate multifunctional oxide structures on carbon fiber devices. This study has demonstrated a new accelerated test method for investigating the corrosion and durability of metallic materials as well.« less

  15. Electrochemical investigation of stainless steel corrosion in a proton exchange membrane electrolyzer cell

    SciTech Connect

    Mo, Jingke; Steen, Stuart M.; Zhang, Feng-Yuan; Toops, Todd J.; Brady, Michael P.; Green, Johney B.

    2015-08-05

    The lack of a fundamental understanding of the corrosion mechanisms in the electrochemical environments of proton exchange membrane (PEM) electrolyzer and/or fuel cells (ECs/FCs) has seriously hindered the improvement of performance and efficiency of PEM ECs/FCs. In this study, a stainless steel mesh was purposely used as an anode gas diffusion layer that was intentionally operated with high positive potentials under harsh oxidative environments in a PEMEC to study the corrosion mechanism of metal migration. A significant amount of iron and nickel cations were determined to transport through the anode catalyst layer, the PEM and the cathode catalyst layer during the PEMEC operation. The formation/deposition of iron oxide and nickel oxide on the carbon paper gas diffusion layer at the cathode side is first revealed by both scanning electron microscope and X-ray diffraction. The results indicate the corrosion elements of iron and nickel are transported from anode to cathode through the catalyst-coated membrane, and deposited on carbon fibers as oxides. This phenomenon could also open a new corrosion-based processing approach to potentially fabricate multifunctional oxide structures on carbon fiber devices. This study has demonstrated a new accelerated test method for investigating the corrosion and durability of metallic materials as well.

  16. Precise Color Tuning via Hybrid Quantum Dot Light-Emitting Electrochemical Cells

    NASA Astrophysics Data System (ADS)

    Norell Bader, Amanda; Ilkevich, Anton; Leger, Janelle

    2010-10-01

    Quantum dots (QDs) are of much interest as the active emitter in an organic light-emitting device due to their size-tunable band-gap energies, allowing device color to be carefully tuned over the entire spectrum by simply varying the size of QDs used. Colloidal QDs are compatible with solution processing techniques used to fabricate polymer light-emitting devices, resulting in inexpensive, low temperature, large area device fabrication on flexible substrates. QDs are more stable and have higher photoluminescence efficiency than organic emitters, but their efficacy in a typical polymer LED is limited by an insulating surface ligand layer that presents a charge tunneling barrier. This leads to unwanted emission from the polymer host material. A light-emitting electrochemical cell (LEC) structure presents a novel solution to this problem by limiting the emissive region thickness in the polymer/QD film. Emission spectra of QD-LECs composed of a two different sizes of QDs blended into a single polymer film show better color purity than polymer-only LECs, with nearly pure emission from the QDs. Relative intensity of the two narrow QD emission peaks is precisely controlled by varying the mass ratio between the QDs, directly changing device color. This novel QD-LEC structure has the potential to improve the performance of polymer optoelectronic devices, particularly in solid-state lighting.

  17. Understanding filamentary growth in electrochemical metallization memory cells using kinetic Monte Carlo simulations.

    PubMed

    Menzel, Stephan; Kaupmann, Philip; Waser, Rainer

    2015-08-01

    We report on a 2D kinetic Monte Carlo model that describes the resistive switching in electrochemical metallization cells. To simulate the switching process, we consider several different processes on the atomic scale: electron-transfer reactions at the boundaries, ion migration, adsorption/desorption from/to interfaces, surface diffusion and nucleation. These processes result in a growth/dissolution of a metallic filament within an insulating matrix. In addition, the model includes electron tunneling between the growing filament and the counter electrode, which allows for simulating multilevel switching. It is shown that the simulation model can reproduce the reported switching kinetics, switching variability and multilevel capabilities of ECM devices. As a major result, the influence of mechanical stress working on the host matrix due to the filamentary growth is investigated. It is demonstrated that the size and shape of the filament depend on the Young's modulus of the insulating matrix. For high values a wire-like structure evolves, whereas the shape is dendritic if the Young's modulus is negligible. PMID:26150320

  18. Method of bonding a conductive layer on an electrode of an electrochemical cell

    DOEpatents

    Bowker, J.C.; Singh, P.

    1989-08-29

    A dense, electronically conductive interconnection layer is bonded onto a porous, tubular, electronically conductive air electrode structure, optionally supported by a ceramic support, by (A) providing an air electrode surface, (B) forming on a selected portion of the electrode surface, without the use of pressure, particles of LaCrO[sub 3] doped with an element selected from the group consisting of Sr, Mg, Ca, Ba, Co, and mixtures thereof, where the particles have a deposit on their surface comprising calcium oxide and chromium oxide; (C) heating the particles with the oxide surface deposit in an oxidizing atmosphere at from 1,300 C to 1,550 C, without the application of pressure, to provide a dense, sintered, interconnection material bonded to the air electrode, where calcium and chromium from the surface deposit are incorporated into the structure of the LaCrO[sub 3]. A solid electrolyte layer can be applied to the uncovered portion of the air electrode, and a fuel electrode can be applied to the solid electrolyte, to provide an electrochemical cell. 4 figs.

  19. Electrochemical performance of microbial fuel cells based on disulfonated poly(arylene ether sulfone) membranes

    NASA Astrophysics Data System (ADS)

    Choi, Tae Hwan; Won, Young-Bin; Lee, Jin-Won; Shin, Dong Won; Lee, Young Moo; Kim, Minkyong; Park, Ho Bum

    2012-12-01

    A microbial fuel cell (MFC) is a bio-electrochemical system that drives a current by mimicking bacterial interactions found in nature. Usually, MFCs use Nafion as a PEM to separate the electrodes while permitting protons transfer between the anode and cathode. However, Nafion is expensive and accounts for a large percentage of the costs in MFC configuration. Here, we show MFCs using hydrocarbon-based PEM, disulfonated poly (arylene ether sulfone) (BPSH), which is considered as one of alternative PEM, and relatively inexpensive as compared with Nafion. BPSH membranes exhibit a comparable performance to Nafion 212. Especially, BPSH 40 and 60 (mole %) have higher proton conductivity than Nafion 212. In a two-chamber system, MFC with BPSH 40 shows higher voltage than that with Nafion 212. MFCs with BPSH 20 and 30 show lower voltage decline than other PEMs. In a single-chamber system, a voltage of MFC with BPSH 40 shows about 30% higher (17 mV) than that with Nafion 212 (13 mV) with internal resistance of 10 ?. In addition, The MFC with BPSH 40 produced about 10% higher maximum power density (126 mW m-2) than that with Nafion 212 (111 mW m-2).

  20. Effect of ultrasounds on the electrochemical synthesis of polypyrrole, application to the adhesion and growth of biological cells.

    PubMed

    Lakard, B; Ploux, L; Anselme, K; Lallemand, F; Lakard, S; Nardin, M; Hihn, J Y

    2009-06-01

    In this study, a new way to synthesize polypyrrole films is presented. This original way consists in the electropolymerization of polypyrrole under high frequency ultrasonic irradiation on conductive fluorine-doped tin oxide surfaces. The polypyrrole films obtained are then compared, in terms of chemical structure and morphology, to polypyrrole films synthesized by standard electrochemical methodology. Next, these polymer films are tested as an alternative to biomaterials that are commonly used as cell culture substrates. Thus, the adhesion and growth of osteoblastics cells and microbial cells on polymer-modified surfaces are investigated by using qualitative observation and quantitative tests. These studies proved the non-toxicity of the polymer films for osteoblastic and microbial cells but also a different behaviour of osteoblastic cells and microbial cells with polypyrrole films. PMID:19359224

  1. Hermetically sealed electrical feedthrough for high temperature secondary cells

    DOEpatents

    Knoedler, Reinhard (Nussloch, DE); Nelson, Paul A. (Wheaton, IL); Shimotake, Hiroshi (Hinsdale, IL); Battles, James E. (Oak Forest, IL)

    1985-01-01

    A passthrough seal is disclosed for electrically isolating the terminal in a lithium/metal sulfide cell from the structural cell housing. The seal has spaced upper and lower insulator rings fitted snuggly between the terminal and an annularly disposed upstanding wall, and outwardly of a powdered insulator also confined between the upstanding wall and terminal. The adjacent surfaces of the upper insulator ring and the respective upstanding wall and terminal are conically tapered, diverging in the axial direction away from the cell interior, and a sealing ring is located between each pair of the adjacent surfaces. The components are sized so that upon appropriate movement of the upper insulator ring toward the lower insulator ring the powdered insulator and sealing rings are each compressed to a high degree. This compacts the powdered insulator thereby rendering the same highly impervious and moreover fuses the sealing rings to and between the adjacent surfaces. The upper and lower insulator rings might be formed of beryllium oxide and/or alumina, the powdered insulator might be formed of boron nitride, and the sealing rings might be formed of aluminum.

  2. Hermetically sealed electrical feedthrough for high temperature secondary cells

    DOEpatents

    Knoedler, R.; Nelson, P.A.; Shimotake, H.; Battles, J.E.

    1983-07-26

    A passthrough seal is disclosed for electrically isolating the terminal in a lithium/metal sulfide cell from the structural cell housing. The seal has spaced upper and lower insulator rings fitted snuggly between the terminal and an annularly disposed upstanding wall, and outwardly of a powdered insulator also confined between the upstanding wall and terminal. The adjacent surfaces of the upper insulator ring and the respective upstanding wall and terminal are conically tapered, diverging in the axial direction away from the cell interior, and a sealing ring is located between each pair of the adjacent surfaces. The components are sized so that upon appropriate movement of the upper insulator ring toward the lower insulator ring the powdered insulator and sealing rings are each compressed to a high degree. This compacts the powdered insulator thereby rendering the same highly impervious and moreover fuses the sealing rings to and between the adjacent surfaces. The upper and lower insulator rings might be formed of beryllium oxide and/or alumina, the powdered insulator might be formed of boron nitride, and the sealing rings might be formed of aluminum.

  3. Technology Base Research Project for electrochemical energy storage

    NASA Astrophysics Data System (ADS)

    Kinoshita, K.

    1987-07-01

    The US DOE Office of Energy Storage and Distribution provides continuing support for an Energy Storage Program, which includes R and D on advanced electrochemical energy storage and conversion systems. A major goal of this program is to develop electrochemical power sources suitable for application in electric vehicles and/or electric load-leveling devices. The program centers on advanced secondary batteries and fuel cells that offer the potential for high performance and low life-cycle costs. The Technology Base Research Project is divided into three major project elements: Exploratory Research, Applied Science Research, and Air Systems Research. Highlights of each project element are summarized according to the appropriate battery system or electrochemical research area. Cells covered include molten salt, lithium, alkaline, zinc/halogen, alkali/sulfur, nonaqueous, metal/air, fuel cell.

  4. FT-IR examination of the development of secondary cell wall in cotton fibers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The secondary cell wall development of cotton fibers harvested at 18, 20, 24, 28, 32, 36 and 40 days after flowering was examined using attenuated total reflection Fourier transform-infrared (ATR FT-IR) spectroscopy. Generally, a progressive intensity increase for bands assigned to cellulose Iß was ...

  5. Development of secondary cell wall in cotton fibers as examined with Fourier transform-infrared spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Our presentation will focus on continuing efforts to examine secondary cell wall development in cotton fibers using infrared Spectroscopy. Cotton fibers harvested at 18, 20, 24, 28, 32, 36 and 40 days after flowering were examined using attenuated total reflection Fourier transform-infrared (ATR FT-...

  6. Chemically and compositionally modified solid solution disordered multiphase nickel hydroxide positive electrode for alkaline rechargeable electrochemical cells

    DOEpatents

    Ovshinsky, Stanford R. (Bloomfield Hills, MI); Corrigan, Dennis (Troy, MI); Venkatesan, Srini (Southfield, MI); Young, Rosa (Troy, MI); Fierro, Christian (Troy, MI); Fetcenko, Michael A. (Rochester Hills, MI)

    1994-01-01

    A high capacity, long cycle life positive electrode for use in an alkaline rechargeable electrochemical cell comprising: a solid solution nickel hydroxide material having a multiphase structure that comprises at least one polycrystalline .gamma.-phase including a polycrystalline .gamma.-phase unit cell comprising spacedly disposed plates with at least one chemical modifier incorporated around the plates, the plates having a range of stable intersheet distances corresponding to a 2.sup.+ oxidation state and a 3.5.sup.+, or greater, oxidation state; and at least one compositional modifier incorporated into the solid solution nickel hydroxide material to promote the multiphase structure.

  7. Pinoresinol reductase 1 impacts lignin distribution during secondary cell wall biosynthesis in Arabidopsis.

    PubMed

    Zhao, Qiao; Zeng, Yining; Yin, Yanbin; Pu, Yunqiao; Jackson, Lisa A; Engle, Nancy L; Martin, Madhavi Z; Tschaplinski, Timothy J; Ding, Shi-You; Ragauskas, Arthur J; Dixon, Richard A

    2015-04-01

    Pinoresinol reductase (PrR) catalyzes the conversion of the lignan (-)-pinoresinol to (-)-lariciresinol in Arabidopsis thaliana, where it is encoded by two genes, PrR1 and PrR2, that appear to act redundantly. PrR1 is highly expressed in lignified inflorescence stem tissue, whereas PrR2 expression is barely detectable in stems. Co-expression analysis has indicated that PrR1 is co-expressed with many characterized genes involved in secondary cell wall biosynthesis, whereas PrR2 expression clusters with a different set of genes. The promoter of the PrR1 gene is regulated by the secondary cell wall related transcription factors SND1 and MYB46. The loss-of-function mutant of PrR1 shows, in addition to elevated levels of pinoresinol, significantly decreased lignin content and a slightly altered lignin structure with lower abundance of cinnamyl alcohol end groups. Stimulated Raman scattering (SRS) microscopy analysis indicated that the lignin content of the prr1-1 loss-of-function mutant is similar to that of wild-type plants in xylem cells, which exhibit a normal phenotype, but is reduced in the fiber cells. Together, these data suggest an association of the lignan biosynthetic enzyme encoded by PrR1 with secondary cell wall biosynthesis in fiber cells. PMID:25107662

  8. Fusion of bone marrow-derived cells with cancer cells: metastasis as a secondary disease in cancer

    PubMed Central

    Pawelek, John M.

    2014-01-01

    This perspective article highlights the leukocyte-cancer cell hybrid theory as a mechanism for cancer metastasis. Beginning from the first proposal of the theory more than a century ago and continuing today with the first proof for this theory in a human cancer, the hybrid theory offers a unifying explanation for metastasis. In this scenario, leukocyte fusion with a cancer cell is a secondary disease superimposed upon the early tumor, giving birth to a new, malignant cell with a leukocyte-cancer cell hybrid epigenome. PMID:24589183

  9. Characterization of high-power lithium-ion cells during constant current cycling. Part I. Cycle performance and electrochemical diagnostics

    SciTech Connect

    Shim, Joongpyo; Striebel, Kathryn A.

    2003-01-24

    Twelve-cm{sup 2} pouch type lithium-ion cells were assembled with graphite anodes, LiNi{sub 0.8}Co{sub 0.15}Al{sub 0.05}O{sub 2} cathodes and 1M LiPF{sub 6}/EC/DEC electrolyte. These pouch cells were cycled at different depths of discharge (100 percent and 70 percent DOD) at room temperature to investigate cycle performance and pulse power capability. The capacity loss and power fade of the cells cycled over 100 percent DOD was significantly faster than the cell cycled over 70 percent DOD. The overall cell impedance increased with cycling, although the ohmic resistance from the electrolyte was almost constant. From electrochemical analysis of each electrode after cycling, structural and/or impedance changes in the cathode are responsible for most of the capacity and power fade, not the consumption of cycleable Li from side-reactions.

  10. Promoting effect of layered titanium phosphate on the electrochemical and photovoltaic performance of dye-sensitized solar cells.

    PubMed

    Cheng, Ping; Chen, Ruihao; Wang, Junfei; Yu, Jianong; Lan, Tian; Wang, Wanjun; Yang, Haijun; Wu, Haixia; Deng, Changsheng

    2010-01-01

    We reported a composite electrolyte prepared by incorporating layered ?-titanium phosphate (?-TiP) into an iodide-based electrolyte using 1-ethyl-3-methylimidazolium tetrafluoroborate(EmimBF4) ionic liquid as solvent. The obtained composite electrolyte exhibited excellent electrochemical and photovoltaic properties compared to pure ionic liquid electrolyte. Both the diffusion coefficient of triiodide (I3-) in the electrolyte and the charge-transfer reaction at the electrode/electrolyte interface were improved markedly. The mechanism for the enhanced electrochemical properties of the composite electrolyte was discussed. The highest conversion efficiency of dye-sensitized solar cell (DSSC) was obtained for the composite electrolyte containing 1wt% ?-TiP, with an improvement of 58% in the conversion efficiency than the blank one, which offered a broad prospect for the fabrication of stable DSSCs with a high conversion efficiency. PMID:20676195

  11. Promoting Effect of Layered Titanium Phosphate on the Electrochemical and Photovoltaic Performance of Dye-Sensitized Solar Cells

    PubMed Central

    2010-01-01

    We reported a composite electrolyte prepared by incorporating layered ?-titanium phosphate (?-TiP) into an iodide-based electrolyte using 1-ethyl-3-methylimidazolium tetrafluoroborate(EmimBF4) ionic liquid as solvent. The obtained composite electrolyte exhibited excellent electrochemical and photovoltaic properties compared to pure ionic liquid electrolyte. Both the diffusion coefficient of triiodide (I3?) in the electrolyte and the charge-transfer reaction at the electrode/electrolyte interface were improved markedly. The mechanism for the enhanced electrochemical properties of the composite electrolyte was discussed. The highest conversion efficiency of dye-sensitized solar cell (DSSC) was obtained for the composite electrolyte containing 1wt% ?-TiP, with an improvement of 58% in the conversion efficiency than the blank one, which offered a broad prospect for the fabrication of stable DSSCs with a high conversion efficiency. PMID:20676195

  12. DISSERTATION IMPACT OF SECONDARY BARRIERS ON CuIn1-xGaxSe2 SOLAR-CELL

    E-print Network

    Sites, James R.

    DISSERTATION IMPACT OF SECONDARY BARRIERS ON CuIn1-xGaxSe2 SOLAR-CELL OPERATION Submitted by Alexei Impact of Secondary Barriers on CuIn1-xGaxSe2 Solar-Cell Operation Thin-film solar cells based on CuInSe2 layers in p-n junctions of CIGS solar cells often improve photodiode properties of the devices. Several

  13. An electrochemical cell for in operando studies of lithium/sodium batteries using a conventional x-ray powder diffractometer

    SciTech Connect

    Shen, Yanbin; Pedersen, Erik E.; Christensen, Mogens; Iversen, Bo B.

    2014-10-15

    An electrochemical cell has been designed for powder X-ray diffraction studies of lithium ion batteries (LIB) and sodium ion batteries (SIB) in operando with high time resolution using a conventional powder X-ray diffractometer. The cell allows for studies of both anode and cathode electrode materials in reflection mode. The cell design closely mimics that of standard battery testing coin cells and allows obtaining powder X-ray diffraction patterns under representative electrochemical conditions. In addition, the cell uses graphite as the X-ray window instead of beryllium, and it is easy to operate and maintain. Test examples on lithium insertion/extraction in two spinel-type LIB electrode materials (Li{sub 4}Ti{sub 5}O{sub 12} anode and LiMn{sub 2}O{sub 4} cathode) are presented as well as first results on sodium extraction from a layered SIB cathode material (Na{sub 0.84}Fe{sub 0.56}Mn{sub 0.44}O{sub 2})

  14. Common histological patterns in glomerular epithelial cells in secondary focal segmental glomerulosclerosis.

    PubMed

    Kuppe, Christoph; Gröne, Hermann-Josef; Ostendorf, Tammo; van Kuppevelt, Toin H; Boor, Peter; Floege, Jürgen; Smeets, Bart; Moeller, Marcus J

    2015-11-01

    Parietal epithelial cells (PECs) are involved in the development of sclerotic lesions in primary focal and segmental glomerulosclerosis (FSGS). Here, the role of PECs was explored in the more common secondary FSGS lesions in 68 patient biopsies, diagnosed with 11 different frequently or rarely encountered glomerular pathologies and additional secondary FSGS lesions. For each biopsy, one section was quadruple stained for PECs (ANXA3), podocytes (synaptopodin), PEC matrix (LKIV69), and Hoechst (nuclei), and a second was quadruple stained for activated PECs (CD44 and cytokeratin-19), PEC matrix, and nuclei. In all lesions, cellular adhesions (synechiae) between Bowman's capsule and the tuft were formed by cells expressing podocyte and/or PEC markers. Cells expressing PEC markers were detected in all FSGS lesions independent of the underlying glomerular disease and often stained positive for markers of activation. Small FSGS lesions, which were hardly identified on PAS sections previously, were detectable by immunofluorescent staining using PEC markers, potentially improving the diagnostic sensitivity to identify these lesions. Thus, similar patterns of cells expressing podocyte and/or PEC markers were found in the formation of secondary FSGS lesions independent of the underlying glomerular disease. Hence, our findings support the hypothesis that FSGS lesions follow a final cellular pathway to nephron loss that includes involvement of cells expressing PEC markers. PMID:25853334

  15. Novel Management of Acute or Secondary Biliary Liver Conditions Using Hepatically Differentiated Human Dental Pulp Cells

    PubMed Central

    Ishkitiev, Nikolay; Imai, Toshio; Tanaka, Tomoko; Fushimi, Naho; Mitev, Vanyo; Okada, Mio; Tominaga, Noriko; Ono, Sachie; Ishikawa, Hiroshi

    2015-01-01

    The current definitive treatment for acute or chronic liver condition, that is, cirrhosis, is liver transplantation from a limited number of donors, which might cause complications after donation. Hence, bone marrow stem cell transplantation has been developed, but the risk of carcinogenesis remains. We have recently developed a protocol for hepatic differentiation of CD117+ stem cells from human exfoliated deciduous teeth (SHED). In the present study, we examine whether SHED hepatically differentiated (hd) in vitro could be used to treat acute liver injury (ALI) and secondary biliary cirrhosis. The CD117+ cell fraction was magnetically separated from SHED and then differentiated into hepatocyte-like cells in vitro. The cells were transplanted into rats with either ALI or induced secondary biliary cirrhosis. Engraftment of human liver cells was determined immunohistochemically and by in situ hybridization. Recovery of liver function was examined by means of histochemical and serological tests. Livers of transplanted animals were strongly positive for human immunohistochemical factors, and in situ hybridization confirmed engraftment of human hepatocytes. The tests for recovery of liver function confirmed the presence of human hepatic markers in the animals' blood serum and lack of fibrosis and functional integration of transplanted human cells into livers. No evidence of malignancy was found. We show that in vitro hdSHED engraft morphologically and functionally into the livers of rats having acute injury or secondary biliary cirrhosis. SHED are readily accessible adult stem cells, capable of proliferating in large numbers before differentiating in vitro. This makes SHED an appropriate and safe stem cell source for regenerative medicine. PMID:25234861

  16. Electrochemical struvite precipitation from digestate with a fluidized bed cathode microbial electrolysis cell.

    PubMed

    Cusick, Roland D; Ullery, Mark L; Dempsey, Brian A; Logan, Bruce E

    2014-05-01

    Microbial electrolysis cells (MECs) can be used to simultaneously convert wastewater organics to hydrogen and precipitate struvite, but scale formation at the cathode surface can block catalytic active sites and limit extended operation. To promote bulk phase struvite precipitation and minimize cathode scaling, a two-chamber MEC was designed with a fluidized bed to produce suspended particles and inhibit scale formation on the cathode surface. MEC operation elevated the cathode pH to between 8.3 and 8.7 under continuous flow conditions. Soluble phosphorus removal using digester effluent ranged from 70 to 85% with current generation, compared to 10-20% for the control (open circuit conditions). At low current densities (?2 mA/m(2)), scouring of the cathode by fluidized particles prevented scale accumulation over a period of 8 days. There was nearly identical removal of soluble phosphorus and magnesium from solution, and an equimolar composition in the collected solids, supporting phosphorus removal by struvite formation. At an applied voltage of 1.0 V, energy consumption from the power supply and pumping (0.2 Wh/L, 7.5 Wh/g-P) was significantly less than that needed by other struvite formation methods based on pH adjustment such as aeration and NaOH addition. In the anode chamber, current generation led to COD oxidation (1.1-2.1 g-COD/L-d) and ammonium removal (7-12 mM) from digestate amended with 1 g/L of sodium acetate. These results indicate that a fluidized bed cathode MEC is a promising method of sustainable electrochemical nutrient and energy recovery method for nutrient rich wastewaters. PMID:24583521

  17. Secondary monoclonal gammopathy of undetermined significance after allogeneic stem cell transplantation in multiple myeloma.

    PubMed

    Schmitz, Marian F; Otten, Henny G; Franssen, Laurens E; van Dorp, Suzanne; Strooisma, Theo; Lokhorst, Henk M; van de Donk, Niels W C J

    2014-12-01

    In the course of multiple myeloma, patients may develop a M-protein band different from the original: secondary monoclonal gammopathy of undetermined significance. In this retrospective single center analysis, we describe the occurrence and clinical relevance of secondary monoclonal gammopathy of undetermined significance after allogeneic stem cell transplantation (post-transplant monoclonal gammopathy of undetermined significance). A total of 138 patients who had undergone 139 allogeneic stem cell transplantations (39.6% in the upfront setting and 60.4% for relapsed multiple myeloma) were included in the study. Sixty-seven (48.2%) patients developed secondary monoclonal gammopathy of undetermined significance, after a median latency of 6.9 months. Secondary monoclonal gammopathy of undetermined significance occurred more often in patients who achieved at least very good partial response after allogeneic stem cell transplantation, compared to partial response or less (54.8% vs. 26.5%; P=0.005). The incidence was also higher in the upfront setting as compared to relapsed disease, or with a sibling donor compared to matched unrelated donor, but less often after T-cell depletion. Importantly, development of post-transplant monoclonal gammopathy of undetermined significance as a time-dependent variable independently predicted for superior progression-free and overall survival (median progression-free survival 37.5 vs. 6.3 months, P<0.001; median overall survival 115.3 vs. 31.0 months, P=0.004). Clinicians should be aware of the benign nature of this phenomenon, and secondary monoclonal gammopathy of undetermined significance should not be confused with relapse or progression of disease. (Trial registered with trialregister.nl; HOVON 108: NTR 2958.). PMID:25193963

  18. Electrochemical cell for in situ electrodeposition of magnetic thin films in a superconducting quantum interference device magnetometer

    NASA Astrophysics Data System (ADS)

    Topolovec, Stefan; Krenn, Heinz; Würschum, Roland

    2015-06-01

    An electrochemical cell is designed and applied for in situ electrodeposition of magnetic thin films in a commercial SQUID magnetometer system. The cell is constructed in such a way that any parasitic contribution of the cell and of the substrate for electrodeposition to the magnetic moment of the deposited film is reduced to a minimum. A remanent minor contribution is readily taken into account by a proper analysis of the detected signal. Thus, a precise determination of the absolute magnetic moment of the electrodeposited magnetic film during its growth and dissolution is achieved. The feasibility of the cell design is demonstrated by performing Co electrodeposition using cyclic voltammetry. For an average Co film thickness of (35.6 ± 3.0) atomic layers, a magnetic moment per Co atom of (1.75 ± 0.11) ?B was estimated, in good agreement with the literature bulk value.

  19. Electrochemical cell for in situ electrodeposition of magnetic thin films in a superconducting quantum interference device magnetometer.

    PubMed

    Topolovec, Stefan; Krenn, Heinz; Würschum, Roland

    2015-06-01

    An electrochemical cell is designed and applied for in situ electrodeposition of magnetic thin films in a commercial SQUID magnetometer system. The cell is constructed in such a way that any parasitic contribution of the cell and of the substrate for electrodeposition to the magnetic moment of the deposited film is reduced to a minimum. A remanent minor contribution is readily taken into account by a proper analysis of the detected signal. Thus, a precise determination of the absolute magnetic moment of the electrodeposited magnetic film during its growth and dissolution is achieved. The feasibility of the cell design is demonstrated by performing Co electrodeposition using cyclic voltammetry. For an average Co film thickness of (35.6 ± 3.0) atomic layers, a magnetic moment per Co atom of (1.75 ± 0.11) ?(B) was estimated, in good agreement with the literature bulk value. PMID:26133846

  20. A 24.4% solar to hydrogen energy conversion efficiency by combining concentrator photovoltaic modules and electrochemical cells

    NASA Astrophysics Data System (ADS)

    Nakamura, Akihiro; Ota, Yasuyuki; Koike, Kayo; Hidaka, Yoshihide; Nishioka, Kensuke; Sugiyama, Masakazu; Fujii, Katsushi

    2015-10-01

    The highest efficiency of 24.4% for the solar-to-hydrogen (STH) energy conversion was obtained in an outdoor field test by combining concentrator photovoltaic (CPV) modules with InGaP/GaAs/Ge three-junction cells and polymer-electrolyte electrochemical (EC) cells. The high efficiency was obtained by using the high-efficiency CPV modules (?31% under the present operation conditions) and the direct connection between the CPV modules and the EC cells with an almost optimized number of elements in series. The STH efficiency bottleneck was clarified to be the efficiency of the CPV modules, the over-potential of the EC cells, and matching of the operation point to the maximal-power point of the CPV modules.

  1. Electrochemical cell for in situ electrodeposition of magnetic thin films in a superconducting quantum interference device magnetometer

    SciTech Connect

    Topolovec, Stefan Würschum, Roland; Krenn, Heinz

    2015-06-15

    An electrochemical cell is designed and applied for in situ electrodeposition of magnetic thin films in a commercial SQUID magnetometer system. The cell is constructed in such a way that any parasitic contribution of the cell and of the substrate for electrodeposition to the magnetic moment of the deposited film is reduced to a minimum. A remanent minor contribution is readily taken into account by a proper analysis of the detected signal. Thus, a precise determination of the absolute magnetic moment of the electrodeposited magnetic film during its growth and dissolution is achieved. The feasibility of the cell design is demonstrated by performing Co electrodeposition using cyclic voltammetry. For an average Co film thickness of (35.6 ± 3.0) atomic layers, a magnetic moment per Co atom of (1.75 ± 0.11) ?{sub B} was estimated, in good agreement with the literature bulk value.

  2. Electrochemical thermodynamic measurement system

    DOEpatents

    Reynier, Yvan (Meylan, FR); Yazami, Rachid (Los Angeles, CA); Fultz, Brent T. (Pasadena, CA)

    2009-09-29

    The present invention provides systems and methods for accurately characterizing thermodynamic and materials properties of electrodes and electrochemical energy storage and conversion systems. Systems and methods of the present invention are configured for simultaneously collecting a suite of measurements characterizing a plurality of interconnected electrochemical and thermodynamic parameters relating to the electrode reaction state of advancement, voltage and temperature. Enhanced sensitivity provided by the present methods and systems combined with measurement conditions that reflect thermodynamically stabilized electrode conditions allow very accurate measurement of thermodynamic parameters, including state functions such as the Gibbs free energy, enthalpy and entropy of electrode/electrochemical cell reactions, that enable prediction of important performance attributes of electrode materials and electrochemical systems, such as the energy, power density, current rate and the cycle life of an electrochemical cell.

  3. Regeneration of anion exchange resins by catalyzed electrochemical reduction

    DOEpatents

    Gu, Baohua (Oak Ridge, TN); Brown, Gilbert M. (Knoxville, TN)

    2002-01-01

    Anion exchange resins sorbed with perchlorate may be regenerated by a combination of chemical reduction of perchlorate to chloride using a reducing agent and an electrochemical reduction of the oxidized reducing agent. Transitional metals including Ti, Re, and V are preferred chemical reagents for the reduction of perchlorate to chloride. Complexing agents such as oxalate are used to prevent the precipitation of the oxidized Ti(IV) species, and ethyl alcohol may be added to accelerate the reduction kinetics of perchlorate. The regeneration may be performed by continuously recycling the regenerating solution through the resin bed and an electrochemical cell so that the secondary waste generation is minimized.

  4. Effect of nano-topographical features of Ti/TiO(2) electrode surface on cell response and electrochemical stability in artificial saliva.

    PubMed

    Demetrescu, I; Pirvu, C; Mitran, V

    2010-08-01

    The paper is a new approach which aims to evaluate the relation between surface aspects (wettability and roughness) of materials based on titanium with native passive TiO(2) as untreated samples and TiO(2) nanotubes as treated discs respectively, their electrochemical stability in artificial saliva, and fibroblast cell behavior. Ti/TiO(2) modified electrodes as nanotubes with 120 nm as diameter were obtained using an electrochemical method as anodizing and surface analysis as SEM, AFM and contact angle measurements were performed to obtain topographical features and wettability. The TiO(2) nanotube structured oxide films electrochemical growth increases the stability of titanium surfaces. The electrochemical behavior of the Ti/TiO(2) nanotube surface was evaluated by corrosion parameters obtained from Tafel plots and electrical parameters for proposed circuits from electrochemical impedance spectroscopy were analyzed. The cell results indicated a slight preference in terms of cell survival and adhesion for nanostructure TiO(2) with a more hydrophilic character and the electrochemical data revealed that such features are connected with better stability in artificial saliva. The roughness seems to be not conclusive for this case. PMID:20189888

  5. 3D CFD Electrochemical and Heat Transfer Model of an Integrated-Planar Solid Oxide Electrolysis Cells

    SciTech Connect

    Grant Hawkes; James E. O'Brien

    2008-10-01

    A three-dimensional computational fluid dynamics (CFD) electrochemical model has been created to model high-temperature electrolysis cell performance and steam electrolysis in a new novel integrated planar porous-tube supported solid oxide electrolysis cell (SOEC). The model is of several integrated planar cells attached to a ceramic support tube. This design is being evaluated with modeling at the Idaho National Laboratory. Mass, momentum, energy, and species conservation and transport are provided via the core features of the commercial CFD code FLUENT. A solid-oxide fuel cell (SOFC) model adds the electrochemical reactions and loss mechanisms and computation of the electric field throughout the cell. The FLUENT SOFC user-defined subroutine was modified for this work to allow for operation in the SOEC mode. Model results provide detailed profiles of temperature, Nernst potential, operating potential, activation over-potential, anode-side gas composition, cathode-side gas composition, current density and hydrogen production over a range of stack operating conditions. Mean per-cell area-specific-resistance (ASR) values decrease with increasing current density. Predicted mean outlet hydrogen and steam concentrations vary linearly with current density, as expected. Effects of variations in operating temperature, gas flow rate, cathode and anode exchange current density, and contact resistance from the base case are presented. Contour plots of local electrolyte temperature, current density, and Nernst potential indicated the effects of heat transfer, reaction cooling/heating, and change in local gas composition. Results are discussed for using this design in the electrolysis mode. Discussion of thermal neutral voltage, enthalpy of reaction, hydrogen production, cell thermal efficiency, cell electrical efficiency, and Gibbs free energy are discussed and reported herein.

  6. Electrochemical stability of Sm0.5Sr0.5CoO3-?-infiltrated YSZ for solid oxide fuel cells/electrolysis cells.

    PubMed

    Fan, Hui; Han, Minfang

    2015-10-10

    Composite SSC (Sm0.5Sr0.5CoO3-?)-YSZ (yttria stabilized zirconia) oxygen electrodes were prepared by an infiltration process. X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM) of the composite electrodes showed the formation of SSC perovskite and a well-connected network of SSC particles in the porous YSZ backbone, respectively. The electrochemical performance of the cell was investigated under both fuel cell and steam electrolysis modes using polarization curves and electrochemical impedance spectroscopy (EIS). The cell experienced a large degradation rate at 700 °C with a constant voltage of 0.7 V for over 100 h under power generation operation. The subsequent post-cell SEM micrograph revealed that agglomeration of the infiltrated SSC particles was possibly the cause for the performance deterioration. Furthermore, the long-term stability of the cell was examined at 700 °C with a constant voltage of 1.3 V under steam electrolysis mode. SEM associated with energy dispersive X-ray spectroscopy (EDS) was employed to characterize the post-test cell after the long-term electrolysis operation and it indicated that besides the agglomeration of SSC particles, the delamination of the SSC-YSZ oxygen electrode from the YSZ electrolyte, as well as segregation of cobalt-enriched particles (particularly cobalt oxides) at the interface, was probably responsible for the cell degradation under the steam electrolysis mode. PMID:26212177

  7. Electrochemical valorisation of glycerol.

    PubMed

    Simões, Mário; Baranton, Stève; Coutanceau, Christophe

    2012-11-01

    The worldwide glycerol stocks are increasing; to make the biodiesel industry sustainable economically, this chemical could be used as a secondary primary raw material. Electric energy or hydrogen and added-value-chemical cogeneration becomes more and more an important research topic for increasing economical and industrial interests towards electrochemical technologies. Studies on glycerol electrooxidation for fuel or electrolysis cell applications are scarce. The valorisation of glycerol is generally performed by organic chemistry reactions forming, for example, esters, glycerol carbonates, ethers, acetals or ketals. Glycerol oxidation is made up of complex pathway reactions that can produce a large number of useful intermediates or valuable fine chemicals with presently limited market impact due to expensive production processes. Many of these chemical oxidation routes lead to significant amounts of undesired by-products, and enzymatic processes are limited. Converse to classical heterogeneous processes, electrocatalytic oxidation processes can be tuned by controlling the nature, composition and structure of the electrocatalyts as well as the electrode potential. Such control may lead to very high selectivity and activity, avoiding or limiting product separation steps. The coupling of glycerol oxidation to produce chemicals with the oxygen reduction reaction in a fuel cell or water reduction reaction in an electrolysis cell on Pt-free catalysts results either in coproduction of electrical energy or hydrogen for energy storage. PMID:23112136

  8. Mechanistic studies of water electrolysis and hydrogen electro-oxidation on high temperature ceria-based solid oxide electrochemical cells.

    PubMed

    Zhang, Chunjuan; Yu, Yi; Grass, Michael E; Dejoie, Catherine; Ding, Wuchen; Gaskell, Karen; Jabeen, Naila; Hong, Young Pyo; Shavorskiy, Andrey; Bluhm, Hendrik; Li, Wei-Xue; Jackson, Gregory S; Hussain, Zahid; Liu, Zhi; Eichhorn, Bryan W

    2013-08-01

    Through the use of ambient pressure X-ray photoelectron spectroscopy (APXPS) and a single-sided solid oxide electrochemical cell (SOC), we have studied the mechanism of electrocatalytic splitting of water (H2O + 2e(-) ? H2 + O(2-)) and electro-oxidation of hydrogen (H2 + O(2-) ? H2O + 2e(-)) at ?700 °C in 0.5 Torr of H2/H2O on ceria (CeO2-x) electrodes. The experiments reveal a transient build-up of surface intermediates (OH(-) and Ce(3+)) and show the separation of charge at the gas-solid interface exclusively in the electrochemically active region of the SOC. During water electrolysis on ceria, the increase in surface potentials of the adsorbed OH(-) and incorporated O(2-) differ by 0.25 eV in the active regions. For hydrogen electro-oxidation on ceria, the surface concentrations of OH(-) and O(2-) shift significantly from their equilibrium values. These data suggest that the same charge transfer step (H2O + Ce(3+) <-> Ce(4+) + OH(-) + H(•)) is rate limiting in both the forward (water electrolysis) and reverse (H2 electro-oxidation) reactions. This separation of potentials reflects an induced surface dipole layer on the ceria surface and represents the effective electrochemical double layer at a gas-solid interface. The in situ XPS data and DFT calculations show that the chemical origin of the OH(-)/O(2-) potential separation resides in the reduced polarization of the Ce-OH bond due to the increase of Ce(3+) on the electrode surface. These results provide a graphical illustration of the electrochemically driven surface charge transfer processes under relevant and nonultrahigh vacuum conditions. PMID:23822749

  9. Characterization of Damp-Heat Degradation of CuInGaSe2 Solar Cell Components and Devices by (Electrochemical) Impedance Spectroscopy: Preprint

    SciTech Connect

    Pern, F. J. J.; Noufi, R.

    2011-09-01

    This work evaluated the capability of (electrochemical) impedance spectroscopy (IS, or ECIS as used here) to monitor damp heat (DH) stability of contact materials, CuInGaSe2 (CIGS) solar cell components, and devices. Cell characteristics and its variation of the CIGS devices were also examined by the ECIS.

  10. Cycling behaviour of Li/Li4Ti5O12 cells studied by electrochemical impedance spectroscopy.

    PubMed

    Schweikert, Nina; Hahn, Horst; Indris, Sylvio

    2011-04-01

    We studied the behaviour of Li/Li(4)Ti(5)O(12) cells by electrochemical impedance spectroscopy to gain insight into the changes at the electrode/electrolyte interfaces during extensive cycling. A simple equivalent-circuit model is able to describe the impedance of the complete battery as a function of both state-of-charge and state-of-degradation. The formation of the solid-electrolyte interface and dendrite growth at the Li metal electrode have a strong influence on the impedance measurements although the battery performance is not significantly affected. PMID:21365085

  11. Solid-State Light-Emitting Electrochemical Cells Based on Cationic Transition Metal Complexes for White Light Generation

    NASA Astrophysics Data System (ADS)

    Su, Hai-Ching; Wong, Ken-Tsung; Wu, Chung-Chih

    Solid-state light-emitting electrochemical cells (LECs) based on cationic transition metal complexes (CTMCs) exhibit several advantages over conventional light-emitting diodes such as simple fabrication processes, low-voltage operation, and high power efficiency. Hence, white CTMC-based LECs may be competitive for lighting applications. In this chapter, we review previous important works on CTMC-based LECs, such as increasing device efficiency, color tuning, lengthening device lifetime, and shortening turn-on time. Our demonstration of white CTMC-based LECs by using the host-guest strategy is then described.

  12. Digitonin synergistically enhances the cytotoxicity of plant secondary metabolites in cancer cells.

    PubMed

    Eid, Safaa Yehia; El-Readi, Mahmoud Zaki; Wink, Michael

    2012-11-15

    In phytotherapy, extracts from medicinal plants are employed which contain mixtures of secondary metabolites. Their modes of action are complex because the secondary metabolites can react with single or multiple targets. The components in a mixture can exert additive or even synergistic activities. In this study, the cytotoxicity of some phytochemicals, including phenolics (EGCG and thymol), terpenoids (menthol, aromadendrene, ?-sitosterol-O-glucoside, and ?-carotene) and alkaloids (glaucine, harmine, and sanguinarine) were investigated alone or in combination with the cytotoxic monodesmosidic steroidal saponin digitonin in Caco-2, MCF-7, CEM/ADR5000, and CCRF-CEM cells. Digitonin was combined in non-toxic concentrations (5?M in each cell line; except in MCF-7 the concentration was 2?M), together with a selection of phenolics, terpenoids, and alkaloids to evaluate potential synergistic or additive effects. An enhanced cytotoxicity was observed in most combinations. Even multi-drug resistant (MDR) cells (such as CEM/ADR5000 cells), with a high expression of P-glycoprotein, were responsive to combinations. Sanguinarine was the most cytotoxic alkaloid against CEM/ADR5000, MCF-7, and CCRF-CEM cells alone and in combination with digitonin. As compared to sanguinarine alone, the combination was 44.53-, 15.38-, and 6.65-fold more toxic in each cell line, respectively. Most combinations synergistically increased the cytotoxicity, stressing the importance of synergy when using multi-target drugs and mixtures in phytotherapy. PMID:23062361

  13. Nonlinear coupled equations for electrochemical cells as developed by the general equation for nonequilibrium reversible-irreversible coupling

    NASA Astrophysics Data System (ADS)

    Bedeaux, Dick; Kjelstrup, Signe; Öttinger, Hans Christian

    2014-09-01

    We show how the Butler-Volmer and Nernst equations, as well as Peltier effects, are contained in the general equation for nonequilibrium reversible and irreversible coupling, GENERIC, with a unique definition of the overpotential. Linear flux-force relations are used to describe the transport in the homogeneous parts of the electrochemical system. For the electrode interface, we choose nonlinear flux-force relationships. We give the general thermodynamic basis for an example cell with oxygen electrodes and electrolyte from the solid oxide fuel cell. In the example cell, there are two activated chemical steps coupled also to thermal driving forces at the surface. The equilibrium exchange current density obtains contributions from both rate-limiting steps. The measured overpotential is identified at constant temperature and stationary states, in terms of the difference in electrochemical potential of products and reactants. Away from these conditions, new terms appear. The accompanying energy flux out of the surface, as well as the heat generation at the surface are formulated, adding to the general thermodynamic basis.

  14. Nonlinear coupled equations for electrochemical cells as developed by the general equation for nonequilibrium reversible-irreversible coupling.

    PubMed

    Bedeaux, Dick; Kjelstrup, Signe; Öttinger, Hans Christian

    2014-09-28

    We show how the Butler-Volmer and Nernst equations, as well as Peltier effects, are contained in the general equation for nonequilibrium reversible and irreversible coupling, GENERIC, with a unique definition of the overpotential. Linear flux-force relations are used to describe the transport in the homogeneous parts of the electrochemical system. For the electrode interface, we choose nonlinear flux-force relationships. We give the general thermodynamic basis for an example cell with oxygen electrodes and electrolyte from the solid oxide fuel cell. In the example cell, there are two activated chemical steps coupled also to thermal driving forces at the surface. The equilibrium exchange current density obtains contributions from both rate-limiting steps. The measured overpotential is identified at constant temperature and stationary states, in terms of the difference in electrochemical potential of products and reactants. Away from these conditions, new terms appear. The accompanying energy flux out of the surface, as well as the heat generation at the surface are formulated, adding to the general thermodynamic basis. PMID:25273407

  15. Alternating-polarity operation for complete regeneration of electrochemical deionization system

    DOEpatents

    Tran, Tri D. (Livermore, CA); Lenz, David J. (Livermore, CA)

    2002-01-01

    An electrically regeneratable battery of electrochemical cells for capacitive deionization (including electrochemical purification) and regeneration of electrodes is operated at alternate polarities during consecutive cycles. By polarizing the cells, ions are removed from the electrolyte and are held in the electric double layers formed at the carbon aerogel surfaces of the electrodes. As the electrodes of each cell of the battery are saturated with the removed ions, the battery is regenerated electrically at a reversed polarity from that during the deionization step of the cycle, thus significantly minimizing secondary wastes.

  16. The Timing of Stimulation and IL-2 Signaling Regulate Secondary CD8 T Cell Responses

    PubMed Central

    Khan, Shaniya H.; Martin, Matthew D.; Starbeck-Miller, Gabriel R.; Xue, Hai-Hui; Harty, John T.; Badovinac, Vladimir P.

    2015-01-01

    Abstract Memory CD8 T cells provide protection to immune hosts by eliminating pathogen-infected cells during re-infection. While parameters influencing the generation of primary (1°) CD8 T cells are well established, the factors controlling the development of secondary (2°) CD8 T cell responses remain largely unknown. Here, we address the mechanisms involved in the generation and development of 2° memory (M) CD8 T cells. We observed that the time at which 1° M CD8 T cells enter into immune response impacts their fate and differentiation into 2° M CD8 T cells. Late-entry of 1° M CD8 T cells into an immune response (relative to the onset of infection) not only facilitated the expression of transcription factors associated with memory formation in 2° effector CD8 T cells, but also influenced the ability of 2° M CD8 T cells to localize within the lymph nodes, produce IL-2, and undergo Ag-driven proliferation. The timing of stimulation of 1° M CD8 T cells also impacted the duration of expression of the high-affinity IL-2 receptor (CD25) on 2° effector CD8 T cells and their sensitivity to IL-2 signaling. Importantly, by blocking or enhancing IL-2 signaling in developing 2° CD8 T cells, we provide direct evidence for the role of IL-2 in controlling the differentiation of Ag-driven 2° CD8 T cell responses. Thus, our data suggest that the process of 1° M to 2° M CD8 T cell differentiation is not fixed and can be manipulated, a notion with relevance for the design of future prime-boost vaccination approaches. PMID:26431533

  17. Abstract--Battery packs for most applications are series strings of electrochemical cells. Due to manufacturing variations,

    E-print Network

    Kimball, Jonathan W.

    . For example, a 12 V lead-acid battery is composed of six individual cells in series. Other secondary battery battery users are aware that SOC balance is necessary, particularly for valve-regulated lead-acid (VRLA) and lithium-ion types [1-7]. For flooded lead-acid batteries, at least in low voltage strings, overcharge

  18. The cycle life chemistry of ambient-temperature secondary lithium cells

    NASA Technical Reports Server (NTRS)

    Somoano, R.; Carter, B. J.; Subba Rao, S.; Shen, D.; Yen, S. P. S.

    1985-01-01

    The Jet Propulsion Laboratory is involved in a NASA-sponsored research program to demonstrate the feasibility of ambient-temperature secondary lithium batteries for geosynchronous space applications. Encouraging cycle life has been demonstrated in sealed, cathode-limited laboratory cells. However, the cell capacity declines with cycle life. The results of recent studies of the lithium electrode passivation chemistry, and of conductive diluents for TiS2 cathodes and their possible contribution to capacity decline, are here presented. Technical issues associated with the unique operational requirements of a geosynchronous mission are also described.

  19. Toxicological characterization of the landfill leachate prior/after chemical and electrochemical treatment: a study on human and plant cells.

    PubMed

    Garaj-Vrhovac, Vera; Oreš?anin, Višnja; Gajski, Goran; Geri?, Marko; Ruk, Damir; Kollar, Robert; Radi? Brkanac, Sandra; Cvjetko, Petra

    2013-10-01

    In this research, toxicological safety of two newly developed methods for the treatment of landfill leachate from the Piškornica (Croatia) sanitary landfill was investigated. Chemical treatment procedure combined chemical precipitation with CaO followed by coagulation with ferric chloride and final adsorption by clinoptilolite. Electrochemical treatment approach included pretreatment with ozone followed by electrooxidation/electrocoagulation and final polishing by microwave irradiation. Cell viability of untreated/treated landfill leachate was examined using fluorescence microscopy. Cytotoxic effect of the original leachate was obtained for both exposure periods (4 and 24 h) while treated samples showed no cytotoxic effect even after prolonged exposure time. The potential DNA damage of the untreated/treated landfill leachate was evaluated by the comet assay and cytokinesis-block micronucleus (CBMN) assay using either human or plant cells. The original leachate exhibited significantly higher comet assay parameters compared to negative control after 24 h exposure. On the contrary, there was no significant difference between negative control and chemically/electrochemically treated leachate for any of the parameters tested. There was also no significant increase in either CBMN assay parameter compared to the negative control following the exposure of the lymphocytes to the chemically or electrochemically treated landfill leachate for both exposure periods while the original sample showed significantly higher number of micronuclei, nucleoplasmic bridges and nuclear buds for both exposure times. Results suggest that both methods are suitable for the treatment of such complex waste effluent due to high removal efficiency of all measured parameters and toxicological safety of the treated effluent. PMID:23790829

  20. The dynamic behavior of thin-film ionic transition metal complex-based light-emitting electrochemical cells

    NASA Astrophysics Data System (ADS)

    Meier, Sebastian B.; Hartmann, David; Winnacker, Albrecht; Sarfert, Wiebke

    2014-09-01

    Light-emitting electrochemical cells (LECs) have received increasing attention during recent years due to their simple architecture, based on solely air-stabile materials, and ease of manufacture in ambient atmosphere, using solution-based technologies. The LEC's active layer offers semiconducting, luminescent as well as ionic functionality resulting in device physical processes fundamentally different as compared with organic light-emitting diodes. During operation, electrical double layers (EDLs) form at the electrode interfaces as a consequence of ion accumulation and electrochemical doping sets in leading to the in situ development of a light-emitting p-i-n junction. In this paper, we comment on the use of impedance spectroscopy in combination with complex nonlinear squares fitting to derive key information about the latter events in thin-film ionic transition metal complex-based light-emitting electrochemical cells based on the model compound bis-2-phenylpyridine 6-phenyl-2,2'-bipyridine iridium(III) hexafluoridophosphate ([Ir(ppy)2(pbpy)][PF6]). At operating voltages below the bandgap potential of the ionic complex used, we obtain the dielectric constant of the active layer, the conductivity of mobile ions, the transference numbers of electrons and ions, and the thickness of the EDLs, whereas the transient thickness of the p-i-n junction is determined at voltages above the bandgap potential. Most importantly, we find that charge transport is dominated by the ions when carrier injection from the electrodes is prohibited, that ion movement is limited by the presence of transverse internal interfaces and that the width of the intrinsic region constitutes almost 60% of the total active layer thickness in steady state at a low operating voltage.

  1. The dynamic behavior of thin-film ionic transition metal complex-based light-emitting electrochemical cells

    SciTech Connect

    Meier, Sebastian B. E-mail: wiebke.sarfert@siemens.com; Hartmann, David; Sarfert, Wiebke E-mail: wiebke.sarfert@siemens.com; Winnacker, Albrecht

    2014-09-14

    Light-emitting electrochemical cells (LECs) have received increasing attention during recent years due to their simple architecture, based on solely air-stabile materials, and ease of manufacture in ambient atmosphere, using solution-based technologies. The LEC's active layer offers semiconducting, luminescent as well as ionic functionality resulting in device physical processes fundamentally different as compared with organic light-emitting diodes. During operation, electrical double layers (EDLs) form at the electrode interfaces as a consequence of ion accumulation and electrochemical doping sets in leading to the in situ development of a light-emitting p-i-n junction. In this paper, we comment on the use of impedance spectroscopy in combination with complex nonlinear squares fitting to derive key information about the latter events in thin-film ionic transition metal complex-based light-emitting electrochemical cells based on the model compound bis-2-phenylpyridine 6-phenyl-2,2´-bipyridine iridium(III) hexafluoridophosphate ([Ir(ppy)?(pbpy)][PF?]). At operating voltages below the bandgap potential of the ionic complex used, we obtain the dielectric constant of the active layer, the conductivity of mobile ions, the transference numbers of electrons and ions, and the thickness of the EDLs, whereas the transient thickness of the p-i-n junction is determined at voltages above the bandgap potential. Most importantly, we find that charge transport is dominated by the ions when carrier injection from the electrodes is prohibited, that ion movement is limited by the presence of transverse internal interfaces and that the width of the intrinsic region constitutes almost 60% of the total active layer thickness in steady state at a low operating voltage.

  2. Secondary Rearrangements and Hypermutation Generate Sufficient B Cell Diversity to Mount Protective Antiviral Immunoglobulin Responses

    PubMed Central

    López-Macías, Constantino; Kalinke, Ulrich; Cascalho, Marilia; Wabl, Matthias; Hengartner, Hans; Zinkernagel, Rolf M.; Lamarre, Alain

    1999-01-01

    Variable (V) region gene replacement was recently implicated in B cell repertoire diversification, but the contribution of this mechanism to antibody responses is still unknown. To investigate the role of V gene replacements in the generation of antigen-specific antibodies, we analyzed antiviral immunoglobulin responses of “quasimonoclonal” (QM) mice. The B cells of QM mice are genetically committed to exclusively express the anti-(4-hydroxy-3-nitrophenyl) acetyl specificity. However, ?20% of the peripheral B cells of QM mice undergo secondary rearrangements and thereby potentially acquire new specificities. QM mice infected with vesicular stomatitis virus (VSV), lymphocytic choriomeningitis virus, or poliovirus mounted virus-specific neutralizing antibody responses. In general, kinetics of the antiviral immunoglobulin responses were delayed in QM mice; however, titers similar to control animals were eventually produced that were sufficient to protect against VSV-induced lethal disease. VSV neutralizing single-chain Fv fragments isolated from phage display libraries constructed from QM mice showed VH gene replacements and extensive hypermutation. Thus, our data demonstrate that secondary rearrangements and hypermutation can generate sufficient B cell diversity in QM mice to mount protective antiviral antibody responses, suggesting that these mechanisms might also contribute to the diversification of the B cell repertoire of normal mice. PMID:10359583

  3. Electrochemical Barriers Made Simple.

    PubMed

    Chan, Karen; Nørskov, Jens K

    2015-07-16

    A major challenge in the theoretical treatment of electrochemical charge transfer barriers is that simulations are performed at constant charge, which leads to dramatic potential shifts along the reaction path. Real electrochemical systems, however, operate at constant potential, which corresponds to a hypothetical model system of infinite size. Previous studies of hydrogen evolution have relied on a computationally costly scheme that extrapolates the barriers calculated on increasingly larger cells, and extension of this scheme to more complex reactions would be prohibitively costly. We present a new method to determine constant potential reaction energetics for simple charge transfer reactions that requires only (1) a single barrier calculation in an electrochemical environment and (2) the corresponding surface charge at the initial, transition, and final states. This method allows for a tremendous reduction in the computational resources required to determine electrochemical barriers and paves the way for a rigorous DFT-based kinetic analysis of electrochemical reactions beyond hydrogen evolution. PMID:26266844

  4. Automated targeting of cells to electrochemical electrodes using a surface chemistry approach for the measurement of quantal exocytosis.

    PubMed

    Barizuddin, Syed; Liu, Xin; Mathai, Joseph C; Hossain, Maruf; Gillis, Kevin D; Gangopadhyay, Shubhra

    2010-07-01

    Here we describe a method to fabricate a multi-channel high-throughput microchip device for measurement of quantal transmitter release from individual cells. Instead of bringing carbon-fiber electrodes to cells, the device uses a surface chemistry approach to bring cells to an array of electrochemical microelectrodes. The microelectrodes are small and "cytophilic" in order to promote adhesion of a single cell whereas all other areas of the chip are covered with a thin "cytophobic" film to block cell attachement and facilitate movement of cells to electrodes. This cytophobic film also insulates unused areas of the conductive film, thus the alignment of cell docking sites to working electrodes is automatic. Amperometric spikes resulting from single-granule fusion events were recorded on the device and had amplitudes and kinetics similar to those measured using carbon-fiber microelectrodes. Use of this device will increase the pace of basic neuroscience research and may also find applications in drug discovery or validation. PMID:21113333

  5. An integrated multifunctional platform based on biotin-doped conducting polymer nanowires for cell capture, release, and electrochemical sensing.

    PubMed

    Hong, Woo Young; Jeon, Seung Hyun; Lee, Eun Sook; Cho, Youngnam

    2014-12-01

    Here, we propose an integrated multifunctional system constructed by conductive disulfide-biotin-doped polypyrrole nanowires (SS-biotin-Ppy NWs) for capture, release, and in situ quantification of circulating tumor cells (CTCs). A well-ordered three-dimensional nanowire structure equipped with a monoclonal antibody offers a significant impact on the cell-capture efficiency, as well as on electrical- or glutathione (GSH)-mediated release of the captured cells. In addition, the electrochemical identification/detection of the captured cancer cells can be directly conducted on the same Ppy NW platform by using horseradish peroxidase (HRP)-labeled and anti-EpCAM-conjugated nanoparticles (HRP/anti-EpCAM Ppy NPs), showing very high sensitivity and specificity. The signal amplification can be clearly attributed to the catalytic response resulting from enzymatic reduction of hydrogen peroxide on Ppy NWs, consequently generating a greatly increased amperometric response with a detection range of 10 to 1 × 10(4) cells and a detection limit of as low as 10 cells. Overall, the proposed Ppy NWs not only present a promising platform for effective cell capture and release but also permit cytosensing capability for on-site analysis. PMID:25192586

  6. Highly exposed Pt nanoparticles supported on porous graphene for electrochemical detection of hydrogen peroxide in living cells.

    PubMed

    Liu, Jian; Bo, Xiangjie; Zhao, Zheng; Guo, Liping

    2015-12-15

    In this study, we developed a novel biosensor based on highly exposed Pt nanoparticles (Pt NPs) decorated porous graphene (PG) for the reliable detection of extracellular hydrogen peroxide (H2O2) released from living cells. The commercially available low-cost hydrophilic CaCO3 spheres were used as template for preparing PG. The porous structure provided larger surface area and more active sites. Due to the porous structure of PG, the Pt NPs supported on PG were not secluded by aggregated graphene layers and were highly exposed to target molecules. Ultrafine Pt NPs were well dispersed and loaded on PG by a method of microwave assistance. Electrochemical performances of the Pt/PG nanocomposites modified glassy carbon electrode (GCE) were investigated. The electrocatalytic reduction of H2O2 showed a wide linear range from 1 to 1477 ?M, with a high sensitivity of 341.14 ?A mM(-1) cm(-2) and a limit of detection (LOD) as low as 0.50 ?M. Moreover, the Pt/PG/GCE exhibited excellent anti-interference property, reproducibility and long-term storage stability. Because of these remarkable analytical advantages, the constructed sensor was used to determine H2O2 released from living cells with satisfactory results. The superior catalytic activity makes Pt/PG nanocomposites a promising candidate for electrochemical sensors and biosensors design. PMID:26120812

  7. In Situ Study of Lithiation and Delithiation of MoS2 Nanosheets Using Electrochemical Liquid Cell Transmission Electron Microscopy.

    PubMed

    Zeng, Zhiyuan; Zhang, Xiaowei; Bustillo, Karen; Niu, Kaiyang; Gammer, Christoph; Xu, Jun; Zheng, Haimei

    2015-08-12

    We report the observation of lithiation/delithiation of MoS2 nanosheets in a LiPF6/EC/DEC commercial electrolyte for the application of lithium-ion batteries using electrochemical liquid cell transmission electron microscopy (TEM). Upon discharge in a voltage range of 1.8-1.2 V, MoS2 on the Ti electrode underwent irreversible decomposition resulting in fragmentation of the MoS2 nanosheets into 5-10 nm MoS2 nanoparticles. Repeated experiments also show that some MoS2 nanosheets do not decompose upon lithiation. Instead, lithiation induced structural expansion and deformation has been observed. A solid-electrolyte interface (SEI) was formed on the anode side of the Ti electrode in contact with Li metal. The SEI layer is composed of LiF nanocrystals distributed within the entire layer with the constituent elements C, O, and F. However, no passivation film was observed on the cathode side of the Ti electrode with MoS2 nanosheets on it. Such an in situ electrochemical liquid cell TEM study sheds light on battery degradation mechanisms. PMID:26147953

  8. Analysis of Phthalate Esters in Mammalian Cell Culture Using a Microfluidic Channel Coupled with an Electrochemical Sensor.

    PubMed

    Noh, Hui-Bog; Gurudatt, Nanjanagudu Ganesh; Won, Mi-Sook; Shim, Yoon-Bo

    2015-07-21

    An analytical tool to monitor trace phthalate was developed using a microfluidic channel device coupled with a novel electrochemical biosensor. At first, the electrochemical sensor was constructed with biomimetic layers to reveal a large hydrogen over potential by controlling the surface charge and hydrophobicity through assembling with a lipid (1,2-dioleoyl-sn-glycero-3-phosphoethanolamine) and a cationic molecule (toluidine blue O) bonded to a conductive polymer. The modified electrode possessing a highly negative polarization potential (approximately -1.8 V vs Ag/AgCl) can uptake sparingly soluble phthalate ester (PEs) compounds in aqueous media. Each sensor probe material was characterized employing SEM, AFM, XPS, QCM, TEM, UV-visible, and impedance spectroscopy. The microfluidic channel is used first to concentrate and separate trace amounts of phthalates, and then the sensor probe is installed at the end of channel. Experimental variables affecting the PEs analysis were assessed and optimized in terms of biomimetic layer composition and analytical conditions. The linear dynamic range and detection limits of the PEs were 0.15 nM-10.0 ?M and ?12.5 pM with relative standard deviations <5%. The proposed method was applied to evaluate the effect of endocrine disruptors on mammalian kidney cells, where the cell samples show in-taking percentages between 1.8 and 7.0% to the total PEs according to the incubation time. PMID:26088015

  9. Morphology, structural and optical properties of iron oxide thin film photoanodes in photoelectrochemical cell: Effect of electrochemical oxidation

    NASA Astrophysics Data System (ADS)

    Maabong, Kelebogile; Machatine, Augusto G.; Hu, Yelin; Braun, Artur; Nambala, Fred J.; Diale, Mmantsae

    2016-01-01

    Hematite (?-Fe2O3) is a promising semiconductor as photoanode in solar hydrogen production from photoelectrolysis of water due to its appropriate band gap, low cost and high electrochemical stability in aqueous caustic electrolytes. Operation of such photoanode in a biased photoelectrochemical cell constitutes an anodization with consequent redox reactions at the electrode surface. ?-Fe2O3 thin film photoanodes were prepared by simple and inexpensive dip coating method on fluorine doped tin oxide (FTO) glass substrate, annealed in air at 500 °C for 2 h, then electrochemically oxidized (anodized) in 1 M KOH at 500 mV for 1 min in dark and light conditions. Changes in structural properties and morphology of ?-Fe2O3 nanoparticles films were investigated by XRD, Raman spectroscopy and a high resolution FE-SEM. The average grain size was observed to increase from ~57 nm for pristine samples to 73 and 77 nm for anodized samples in dark and light respectively. Broadening and red shift in Raman spectra in anodized samples may be attributed to lattice expansion upon oxidation. The UV-visible measurements revealed enhanced absorption in the photoanodes after the treatment. The findings suggest that the anodization of the photoelectrode in a biased cell causes not only changes of the molecular structure at the surface, but also changes in the crystallographic structure which can be detected with x-ray diffractometry.

  10. Formation of surface morphology of silicon solar cells by means of two-step photo-electrochemical etching and their characterization

    NASA Astrophysics Data System (ADS)

    Shatkovskis, E.; Zagadskij, V.; Jukna, A.; Boris, R.; Antonovic, V.; Stupakova, J.; Mitkevicius, R.; Baradinskaite, A.; Keriene, J.

    2014-10-01

    The electrochemical etching of porous silicon offers many diverse opportunities for production of complex porous silicon structures located not only on the surface but also in a bulk of the silicon devices. A specific technological regime, the photo-electrochemical etching can affect bulk of the silicon device but at the same time saving its textured surface almost unchanged. Our group is the first who investigated the silicon solar cells with textured surface modified by means of photo-electrochemical etching. Etched devices demonstrated better photoelectrical characteristics if compare ones with unmodified solar cells. Our current work presents results on research of solar cells photoelectrochemically treated in HF: ethanol solution. Applied etching regime allowed us to modify the emitter's volume at the same time affecting only minimally the surface of the solar cell itself. SEM micrographs show the elevations, ripples, bumps, cracks etc. on the surface of photo-electrochemically treated solar cells. The optical ellipsometer spectra, optical microscope measurements results, SEM micrographs of surface morphology as well as light reflectivity of the photoelectrochemically treated and untreated surfaces of the solar cells investigated and discussed in this work.

  11. Electrochemical lactate biosensor based upon chitosan/carbon nanotubes modified screen-printed graphite electrodes for the determination of lactate in embryonic cell cultures.

    PubMed

    Hernández-Ibáñez, Naiara; García-Cruz, Leticia; Montiel, Vicente; Foster, Christopher W; Banks, Craig E; Iniesta, Jesús

    2016-03-15

    l-lactate is an essential metabolite present in embryonic cell culture. Changes of this important metabolite during the growth of human embryo reflect the quality and viability of the embryo. In this study, we report a sensitive, stable, and easily manufactured electrochemical biosensor for the detection of lactate within embryonic cell cultures media. Screen-printed disposable electrodes are used as electrochemical sensing platforms for the miniaturization of the lactate biosensor. Chitosan/multi walled carbon nanotubes composite have been employed for the enzymatic immobilization of the lactate oxidase enzyme. This novel electrochemical lactate biosensor analytical efficacy is explored towards the sensing of lactate in model (buffer) solutions and is found to exhibit a linear response towards lactate over the concentration range of 30.4 and 243.9µM in phosphate buffer solution, with a corresponding limit of detection (based on 3-sigma) of 22.6µM and exhibits a sensitivity of 3417±131µAM(-1) according to the reproducibility study. These novel electrochemical lactate biosensors exhibit a high reproducibility, with a relative standard deviation of less than 3.8% and an enzymatic response over 82% after 5 months stored at 4°C. Furthermore, high performance liquid chromatography technique has been utilized to independently validate the electrochemical lactate biosensor for the determination of lactate in a commercial embryonic cell culture medium providing excellent agreement between the two analytical protocols. PMID:26579934

  12. Analysis of cytogenetic effects of the secondary radiation resulting from 70 GeV protons of chinese hamster cells

    NASA Astrophysics Data System (ADS)

    Akhmadieva, A. Kh.; Aptikaeva, G. Ph.; Livanova, I. A.; Antipov, A. V.; Akoev, I. G.; Ganassi, E. E.

    The cell culture of a Chinese hamster was irradiated on a Serpuchov proton synchrotron at a dose of 0.5-4 Gy and a dose rate of 1 Gy/min and by gamma-irradiation at dose 1-5 Gy and dose rate 1.2-1.4 Gy/min. The effect of radiation on the cell culture was judged from chromosomal aberrations in G2-stage of cell cycle and micronuclear test. The relative biological efficience of the secondary radiation was approximately 3. Modifying effect of caffeine on the cells irradiated by secondary radiation of synchrotron was not observed. In the presence of caffeine the effect of ?-irradiation practically is increased up to the level observed upon secondary irradiation. This suggests that secondary radiation inhibits the repair of the cytogenetic damage.

  13. Investigation of chemical and electrochemical reactions mechanisms in a direct carbon fuel cell using olive wood charcoal as sustainable fuel

    NASA Astrophysics Data System (ADS)

    Elleuch, Amal; Halouani, Kamel; Li, Yongdan

    2015-05-01

    Direct carbon fuel cell (DCFC) is a high temperature fuel cell using solid carbon as fuel. The use of environmentally friendly carbon material constitutes a promising option for the DCFC future. In this context, this paper focuses on the use of biomass-derived charcoal renewable fuel. A practical investigation of Tunisian olive wood charcoal (OW-C) in planar DCFCs is conducted and good power density (105 mW cm-2) and higher current density (550 mA cm-2) are obtained at 700 °C. Analytical and predictive techniques are performed to explore the relationships between fuel properties and DCFC chemical and electrochemical mechanisms. High carbon content, carbon-oxygen groups and disordered structure, are the key parameters allowing the achieved good performance. Relatively complex chain reactions are predicted to explain the gas evolution within the anode. CO, H2 and CH4 participation in the anodic reaction is proved.

  14. Treatment of electrochemical cell components with lithium tetrachloroaluminate (LiAlCl.sub.4) to promote electrolyte wetting

    DOEpatents

    Eberhart, James G. (Naperville, IL); Battles, James E. (Oak Forest, IL)

    1980-01-01

    Electrochemical cell components such as interelectrode separators, retaining screens and current collectors are contacted with lithium tetrachloroaluminate prior to contact with molten electrolytic salt to improve electrolyte wetting. The LiAlCl.sub.4 can be applied in powdered, molten or solution form but, since this material has a lower melting point than the electrolytic salt used in high-temperature cells, the powdered LiAlCl.sub.4 forms a molten flux prior to contact by the molten electrolyte when both materials are initially provided in solid form. Components of materials such as boron nitride and other materials which are difficult to wet with molten salts are advantageously treated by this process.

  15. Note: Electrochemical cell for in operando X-ray diffraction measurements on a conventional X-ray diffractometer.

    PubMed

    Hartung, Steffen; Bucher, Nicolas; Bucher, Ramona; Srinivasan, Madhavi

    2015-08-01

    Electrochemical in operando X-ray diffraction (XRD) is a powerful method to analyze structural changes of energy storage materials while inserting/de-inserting charge carriers, such as Li- or Na-ions, into/from a host structure. The design of an XRD in operando cell is presented, which enables the use of thin (6 ?m) aluminum foil as X-ray window as a non-toxic alternative to conventional beryllium windows. Owing to the reduced thickness, diffraction patterns and their changes during cycling can be observed with excellent quality, which was demonstrated for two cathode materials for sodium-ion batteries in a half-cell set-up, P2-Na(0.7)MnO2 and Na(2.55)V6O16 ? 0.6H2O. PMID:26329242

  16. Note: Electrochemical cell for in operando X-ray diffraction measurements on a conventional X-ray diffractometer

    NASA Astrophysics Data System (ADS)

    Hartung, Steffen; Bucher, Nicolas; Bucher, Ramona; Srinivasan, Madhavi

    2015-08-01

    Electrochemical in operando X-ray diffraction (XRD) is a powerful method to analyze structural changes of energy storage materials while inserting/de-inserting charge carriers, such as Li- or Na-ions, into/from a host structure. The design of an XRD in operando cell is presented, which enables the use of thin (6 ?m) aluminum foil as X-ray window as a non-toxic alternative to conventional beryllium windows. Owing to the reduced thickness, diffraction patterns and their changes during cycling can be observed with excellent quality, which was demonstrated for two cathode materials for sodium-ion batteries in a half-cell set-up, P2-Na0.7MnO2 and Na2.55V6O16 ? 0.6H2O.

  17. Non-Faradaic Electrochemical Detection of Exocytosis from Mast and Chromaffin Cells Using Floating-Gate MOS Transistors.

    PubMed

    Jayant, Krishna; Singhai, Amit; Cao, Yingqiu; Phelps, Joshua B; Lindau, Manfred; Holowka, David A; Baird, Barbara A; Kan, Edwin C

    2015-01-01

    We present non-faradaic electrochemical recordings of exocytosis from populations of mast and chromaffin cells using chemoreceptive neuron MOS (C?MOS) transistors. In comparison to previous cell-FET-biosensors, the C?MOS features control (CG), sensing (SG) and floating gates (FG), allows the quiescent point to be independently controlled, is CMOS compatible and physically isolates the transistor channel from the electrolyte for stable long-term recordings. We measured exocytosis from RBL-2H3 mast cells sensitized by IgE (bound to high-affinity surface receptors Fc?RI) and stimulated using the antigen DNP-BSA. Quasi-static I-V measurements reflected a slow shift in surface potential () which was dependent on extracellular calcium ([Ca]o) and buffer strength, which suggests sensitivity to protons released during exocytosis. Fluorescent imaging of dextran-labeled vesicle release showed evidence of a similar time course, while un-sensitized cells showed no response to stimulation. Transient recordings revealed fluctuations with a rapid rise and slow decay. Chromaffin cells stimulated with high KCl showed both slow shifts and extracellular action potentials exhibiting biphasic and inverted capacitive waveforms, indicative of varying ion-channel distributions across the cell-transistor junction. Our approach presents a facile method to simultaneously monitor exocytosis and ion channel activity with high temporal sensitivity without the need for redox chemistry. PMID:26686301

  18. Electrochemical Characteristics of Cell Cultured Ti-Nb-Zr Alloys After Nano-Crystallized Si-HA Coating.

    PubMed

    Jeong, Yong-Hoon; Choe, Han-Cheol

    2015-01-01

    The aim of this study was to investigate the electrochemical characteristics of nano crystallized Si-HA coating on Ti-Nb-Zr alloy after human osteoblast like (HOB) cell attachment. The Ti-Nb-Zr alloy was manufactured with 35 wt.% of Nb and 10 wt.% of Zr by arc melting furnace to appropriate physical properties as biomaterials. The HA and Si-substituted coatings were prepared by electron-beam physical vapor deposition method with 0.5, 0.8 and 1.2 wt.% of Si contents, and nano aging treatment was performed 500 degrees C for 1 h. The characteristics of coating surface were analyzed by field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction, respectively. To evaluate of cell attachment on cell cultured surface, the potentiodynamic test was performed on the surface using HOB cells. The results showed that the Si-HA coating surface showed higher tendency of cell attachment than that of single HA coating, corrosion resistance value was increased by dense of cell attachment. PMID:26328326

  19. Non-Faradaic Electrochemical Detection of Exocytosis from Mast and Chromaffin Cells Using Floating-Gate MOS Transistors

    PubMed Central

    Jayant, Krishna; Singhai, Amit; Cao, Yingqiu; Phelps, Joshua B.; Lindau, Manfred; Holowka, David A.; Baird, Barbara A.; Kan, Edwin C.

    2015-01-01

    We present non-faradaic electrochemical recordings of exocytosis from populations of mast and chromaffin cells using chemoreceptive neuron MOS (C?MOS) transistors. In comparison to previous cell-FET-biosensors, the C?MOS features control (CG), sensing (SG) and floating gates (FG), allows the quiescent point to be independently controlled, is CMOS compatible and physically isolates the transistor channel from the electrolyte for stable long-term recordings. We measured exocytosis from RBL-2H3 mast cells sensitized by IgE (bound to high-affinity surface receptors Fc?RI) and stimulated using the antigen DNP-BSA. Quasi-static I-V measurements reflected a slow shift in surface potential () which was dependent on extracellular calcium ([Ca]o) and buffer strength, which suggests sensitivity to protons released during exocytosis. Fluorescent imaging of dextran-labeled vesicle release showed evidence of a similar time course, while un-sensitized cells showed no response to stimulation. Transient recordings revealed fluctuations with a rapid rise and slow decay. Chromaffin cells stimulated with high KCl showed both slow shifts and extracellular action potentials exhibiting biphasic and inverted capacitive waveforms, indicative of varying ion-channel distributions across the cell-transistor junction. Our approach presents a facile method to simultaneously monitor exocytosis and ion channel activity with high temporal sensitivity without the need for redox chemistry. PMID:26686301

  20. Protein-inorganic hybrid nanoflowers as ultrasensitive electrochemical cytosensing interfaces for evaluation of cell surface sialic acid.

    PubMed

    Cao, Hongmei; Yang, Da-Peng; Ye, Daixin; Zhang, Xianxia; Fang, Xueen; Zhang, Song; Liu, Baohong; Kong, Jilie

    2015-06-15

    The identification of biocompatible nanomaterials with high conductivities as sensing interfaces is important in developing novel electrochemical cytosensors. We prepared a novel protein-inorganic nanomaterial-bovine serum albumin (BSA) incorporated Ag nanoflowers with three-dimensional porous architectures, using a simple biomimetic method. The BSA-incorporated Ag nanoflowers were modified on a glassy carbon electrode (GCE) surface and conjugated with a targeting lectin molecule, i.e., Sambucus nigra agglutinin (SNA), for sensing DLD-1 human colon cancer cells. The BSA-incorporated Ag nanoflowers were a suitable platform, and showed improved cell-immobilization capacity, and good biocompatibility, with retention of activity of the immobilized cells. These properties are attributed to the large surface area of the porous structure and the natural BSA layer acting as a biocompatible support. The attachment of DLD-1 cells to the GCE increased the electron-transfer resistance, with a good correlation with the logarithm of the concentration from 1.35×10(2) to 1.35×10(7) cells mL(-1), with a low detection limit of 40 cells mL(-1). Based on the affinity between SNA and sialic acid (SA), the UV-vis absorption spectrum of the one-step reaction between SA and acidic ninhydrin indicated that the average number of SA molecules on a single living DLD-1 cell surface was approximately 2.16×10(12). This proposed cytosensing strategy had good reproducibility, acceptable precision, and high specificity for SA-over-expressed cells, indicating that it has potential applications for the early monitoring of tumor cells and convenient evaluation of SA on living cells. PMID:25599845

  1. NAC-MYB-based transcriptional regulation of secondary cell wall biosynthesis in land plants

    PubMed Central

    Nakano, Yoshimi; Yamaguchi, Masatoshi; Endo, Hitoshi; Rejab, Nur Ardiyana; Ohtani, Misato

    2015-01-01

    Plant cells biosynthesize primary cell walls (PCW) in all cells and produce secondary cell walls (SCWs) in specific cell types that conduct water and/or provide mechanical support, such as xylem vessels and fibers. The characteristic mechanical stiffness, chemical recalcitrance, and hydrophobic nature of SCWs result from the organization of SCW-specific biopolymers, i.e., highly ordered cellulose, hemicellulose, and lignin. Synthesis of these SCW-specific biopolymers requires SCW-specific enzymes that are regulated by SCW-specific transcription factors. In this review, we summarize our current knowledge of the transcriptional regulation of SCW formation in plant cells. Advances in research on SCW biosynthesis during the past decade have expanded our understanding of the transcriptional regulation of SCW formation, particularly the functions of the NAC and MYB transcription factors. Focusing on the NAC-MYB-based transcriptional network, we discuss the regulatory systems that evolved in land plants to modify the cell wall to serve as a key component of structures that conduct water and provide mechanical support. PMID:25999964

  2. Cyto-sensing in electrochemical lab-on-paper cyto-device for in-situ evaluation of multi-glycan expressions on cancer cells.

    PubMed

    Su, Min; Ge, Lei; Kong, Qingkun; Zheng, Xiaoxiao; Ge, Shenguang; Li, Nianqiang; Yu, Jinghua; Yan, Mei

    2015-01-15

    A novel electrochemical lab-on-paper cyto-device (ELPCD) was fabricated to demonstrate sensitive and specific cancer cell detection as well as in-situ monitoring of multi-glycans on living cancer cells. In this ELPCD, aptamers modified three-dimensional macroporous Au-paper electrode (Au-PE) was employed as the working electrode for specific and efficient cancer cell capture. Using a sandwich format, sensitive and reproducible cell detection was achieved in this ELPCD on the basis of the electrochemical signal amplification of the Au-PE and the horseradish peroxidase-lectin electrochemical probe. The ELPCD displayed excellent analytical performance for the detection of four K562 cells with a wide linear calibration range from 550 to 2.0×10(7) cells mL(-1). Then, this ELPCD was successfully applied to determine cell-surface multi-glycans in parallel and in-situ monitor multi-glycans expression on living cells in response to drug treatment through in-electrode 3D cell culture. The proposed method provides promising application in decipherment of the glycomic codes as well as clinical diagnosis and treatment in early process of cancer. PMID:25104432

  3. Sensitive electrochemical aptamer cytosensor for highly specific detection of cancer cells based on the hybrid nanoelectrocatalysts and enzyme for signal amplification.

    PubMed

    Sun, Duanping; Lu, Jing; Zhong, Yuwen; Yu, Yanyan; Wang, Yu; Zhang, Beibei; Chen, Zuanguang

    2016-01-15

    Human cancer is becoming a leading cause of death in the world and the development of a straightforward strategy for early detection of cancer is urgently required. Herein, a sandwich-type electrochemical aptamer cytosensor was developed for detection of human liver hepatocellular carcinoma cells (HepG2) based on the hybrid nanoelectrocatalysts and enzyme for signal amplification. The thiolated TLS11a aptamers were used as a selective bio-recognition element, attached to the gold nanoparticles (AuNPs) modified the glassy carbon electrode (GCE) surface. Meanwhile, the electrochemical nanoprobes were fabricated through the G-quadruplex/hemin/aptamer complexes and horseradish peroxidase (HRP) immobilized on the surfaces of Au@Pd core-shell nanoparticle-modified magnetic Fe3O4/MnO2 beads (Fe3O4/MnO2/Au@Pd). After the target cells were captured, the hybrid nanoprobes were further assembled to form an aptamer-cell-nanoprobes sandwich-like system on the electrode surface. Then, hybrid Fe3O4/MnO2/Au@Pd nanoelectrocatalysts, G-quadruplex/hemin HRP-mimicking DNAzymes and the natural HRP enzyme efficiently catalyzed the oxidation of hydroquinone (HQ) with H2O2, amplifying the electrochemical signals and improving the detection sensitivity. This electrochemical cytosensor delivered a wide detection range of 1×10(2)-1×10(7)cellsmL(-1), high sensitivity with a low detection limit of 15cellsmL(-1), good selectivity and repeatability. Finally, an electrochemical reductive desorption method was performed to break gold-thiol bond and desorb the components on the AuNPs/GCE for regenerating the cytosensor. These results have demonstrated that the electrochemical cytosensor has the potential to be a feasible tool for cost-effective cancer cell detection in early cancer diagnosis. PMID:26332382

  4. Solid state electrochemical composite

    DOEpatents

    Visco, Steven J. (Berkeley, CA); Jacobson, Craig P. (Moraga, CA); DeJonghe, Lutgard C. (Lafayette, CA)

    2009-06-30

    Provided is a composite electrochemical device fabricated from highly electronically conductive materials such as metals, metal alloys, or electronically conductive ceramics. The electronic conductivity of the electrode substrate is maximized. The invention allows for an electrode with high electronic conductivity and sufficient catalytic activity to achieve high power density in ionic (electrochemical) devices such as fuel cells and electrolytic gas separation systems including oxygen generation system.

  5. Dual-aptamer modification generates a unique interface for highly sensitive and specific electrochemical detection of tumor cells.

    PubMed

    Qu, Liming; Xu, Jinhai; Tan, Xiaofang; Liu, Zhuang; Xu, Ligeng; Peng, Rui

    2014-05-28

    Because circulating tumor cells (CTCs) have been proven to be an important clue of the tumor metastasis, their detection thus plays a pivotal role in the diagnosis and prognosis of cancer. Herein, we fabricate an electrochemical sensor by directly conjugating two cell-specific aptamers, TLS1c and TLS11a, which specifically recognize MEAR cancer cells, to the surface of a glassy carbon electrode (GCE) via the formation of amide bonds. The two aptamers are simultaneously conjugated to the GCE surface via precisely controlled linkers: TLS1c through a flexible linker (a single-stranded DNA T15; ss-TLS1c) and TLS11a through a rigid linker (a double-stranded DNA T15/A15; ds-TLS11a). It is found that such ss-TLS1c/ds-TLS11a dual-modified GCEs show greatly improved sensitivity in comparison with those modified with a single type of aptamer alone or ds-TLS1c/ds-TLS11a with both rigid linkers, suggesting that our optimized, rationally designed electrode-aptamer biosensing interface may enable better recognition and thus more sensitive detection of tumor cells. Through the utilization of this dual-aptamer-modified GCE, as few as a single MEAR cell in 10(9) whole blood cells can be successfully detected with a linear range of 1-14 MEAR cells. Our work demonstrates a rather simple yet well-designed and ultrasensitive tumor cell detection method based on the cell-specific aptamer-modified GCE, showing a promising potential for further CTC-related clinical applications. PMID:24801611

  6. Carbohydrate derivative-functionalized biosensing toward highly sensitive electrochemical detection of cell surface glycan expression as cancer biomarker.

    PubMed

    Zhang, Xinai; Lu, Wenjie; Shen, Jianzhong; Jiang, Yuxiang; Han, En; Dong, Xiaoya; Huang, Jiali

    2015-12-15

    Accurate and highly sensitive detection of glycan expression on cell surface is extremely important for cancer diagnosis and therapy. Herein, a carbohydrate derivative-functionalized biosensor was developed for electrochemical detection of the expression level of cell surface glycan (mannose used as model). Thiomannosyl dimer was synthesized to design the thiomannosyl-functionalized biosensor by direct and rapid one-step protocols. The biosensing surface-confined mannose could effectively mimic the presentation of cell surface mannose and was responsible for competing with mannose on cancer cells in incubation solution. Greatly enhanced sensitivity was achieved by exploiting the excellent conductivity of multiwalled carbon nanotube/Au nanoparticle (MWNT/AuNP), the amplification effect of MWNTs, and the favorable catalytic ability of horseradish peroxidase (HRP). Using competitive strategy, the developed biosensor exhibits attractive performances for the analysis of mannose expression with rapid response, high sensitivity and accuracy, and possesses great promise for evaluation of cell surface glycan expression by using a greater variety of lectins. PMID:26143470

  7. Bio-electrochemical characterization of air-cathode microbial fuel cells with microporous polyethylene/silica membrane as separator.

    PubMed

    Kircheva, Nina; Outin, Jonathan; Perrier, Gérard; Ramousse, Julien; Merlin, Gérard; Lyautey, Emilie

    2015-12-01

    The aim of this work was to study the behavior over time of a separator made of a low-cost and non-selective microporous polyethylene membrane (RhinoHide®) in an air-cathode microbial fuel cell with a reticulated vitreous carbon foam bioanode. Performances of the microporous polyethylene membrane (RhinoHide®) were compared with Nafion®-117 as a cationic exchange membrane. A non-parametric test (Mann-Whitney) done on the different sets of coulombic or energy efficiency data showed no significant difference between the two types of tested membrane (p<0.05). Volumetric power densities were ranging from 30 to 90 W·m(-3) of RVC foam for both membranes. Similar amounts of biomass were observed on both sides of the polyethylene membrane illustrating bacterial permeability of this type of separator. A monospecific denitrifying population on cathodic side of RhinoHide® membrane has been identified. Electrochemical impedance spectroscopy (EIS) was used at OCV conditions to characterize electrochemical behavior of MFCs by equivalent electrical circuit fitted on both Nyquist and Bode plots. Resistances and pseudo-capacitances from EIS analyses do not differ in such a way that the nature of the membrane could be considered as responsible. PMID:26073676

  8. Electrochemical characterization of anodic biofilms enriched with glucose and acetate in single-chamber microbial fuel cells.

    PubMed

    Yuan, Yong; Zhou, Shungui; Xu, Nan; Zhuang, Li

    2011-02-01

    This study used a simple and efficient electrochemical technique, cyclic voltammogram (CV), to quantitatively measure the electron transfer capability of anodic biofilms enriched with acetate and glucose in single-chamber microbial fuel cells (MFCs). Two pairs of distinct redox peaks were observed by CV measurements in both biofilms, identical to the CV features of a pure Geobacter strain. The CVs also revealed a higher density of electroactive species in the acetate-enriched biofilm than that in the glucose-enriched biofilm. Based on the scan rate analysis, the apparent electron transfer rate constants (k(app)) in the acetate-enriched biofilm and glucose-enriched biofilm were determined to be 0.82 and 0.15s(-1), respectively, which supported the higher power output of the MFC fed with acetate. Meanwhile, the pH dependence of the biofilms was studied by monitoring the changes of the biofilm redox peak currents and potentials. It is concluded that redox reaction of the electrochemical active species in biofilms is pH dependent, and both electrons and protons are involved in the redox reactions. PMID:21050727

  9. Mesenchymal Stem Cell-Based Treatment for Microvascular and Secondary Complications of Diabetes Mellitus

    PubMed Central

    Davey, Grace C.; Patil, Swapnil B.; O’Loughlin, Aonghus; O’Brien, Timothy

    2014-01-01

    The worldwide increase in the prevalence of Diabetes mellitus (DM) has highlighted the need for increased research efforts into treatment options for both the disease itself and its associated complications. In recent years, mesenchymal stromal cells (MSCs) have been highlighted as a new emerging regenerative therapy due to their multipotency but also due to their paracrine secretion of angiogenic factors, cytokines, and immunomodulatory substances. This review focuses on the potential use of MSCs as a regenerative medicine in microvascular and secondary complications of DM and will discuss the challenges and future prospects of MSCs as a regenerative therapy in this field. MSCs are believed to have an important role in tissue repair. Evidence in recent years has demonstrated that MSCs have potent immunomodulatory functions resulting in active suppression of various components of the host immune response. MSCs may also have glucose lowering properties providing another attractive and unique feature of this therapeutic approach. Through a combination of the above characteristics, MSCs have been shown to exert beneficial effects in pre-clinical models of diabetic complications prompting initial clinical studies in diabetic wound healing and nephropathy. Challenges that remain in the clinical translation of MSC therapy include issues of MSC heterogeneity, optimal mode of cell delivery, homing of these cells to tissues of interest with high efficiency, clinically meaningful engraftment, and challenges with cell manufacture. An issue of added importance is whether an autologous or allogeneic approach will be used. In summary, MSC administration has significant potential in the treatment of diabetic microvascular and secondary complications but challenges remain in terms of engraftment, persistence, tissue targeting, and cell manufacture PMID:24936198

  10. Electrochemical fabrication of capacitors

    DOEpatents

    Mansour, Azzam N. (Fairfax Sta., VA); Melendres, Carlos A. (Lemont, IL)

    1999-01-01

    A film of nickel oxide is anodically deposited on a graphite sheet held in osition on an electrochemical cell during application of a positive electrode voltage to the graphite sheet while exposed to an electrolytic nickel oxide solution within a volumetrically variable chamber of the cell. An angularly orientated x-ray beam is admitted into the cell for transmission through the deposited nickel oxide film in order to obtain structural information while the film is subject to electrochemical and in-situ x-ray spectroscopy from which optimum film thickness, may be determined by comparative analysis for capacitor fabrication purposes.

  11. Electrochemical and energetic characteristics of new dye-sensitizers for photovoltaic cells

    NASA Astrophysics Data System (ADS)

    Kobasa, Igor; Odosiy, Lyubomyra; Kurdyukova, Iryna; Ishchenko, Olexandr; Kurek, Stefan

    2015-06-01

    The influence of the dye structure on the spectral and electrochemical characteristics has been investigated for a series of the anionic and intraionic polymethine dyes (PDs) of the tetranitrofluorene family. The reduction and oxidation potentials were determined by cyclic voltammetry (CVA), and HOMO and LUMO energy levels were calculated in order to predict the applicability of the dyes as TiO2 sensitizing agents. Some types of the PD/TiO2 heterostructures (HSs) were built and their photocatalytic activity (PA) was determined using the model reaction of iodide anion oxidation.

  12. Novel concepts in electrochemical solar cells. Quarterly technical progress report, December 15, 1980-March 15, 1981

    SciTech Connect

    Not Available

    1981-01-01

    During the past quarter, the following areas were emphasized: (a) characterization of redox couples with very positive potentials in room-temperature AlCl/sub 3/-BPC electrolytes and comparison of the electrochemical behavior of decamethyl ferrocene in these electrolytes with the previously-studied ferrocene/ferricenium ion couple, (b) photoelectrochemical characterization of CdSe thin-film anodes in aqueous polysulfide electrolytes and (c) refinement of the admittance measurement technique for extraction of Mott-Schottky parameters. The results of research in these areas are detailed in turn below.

  13. Method of making sulfur tolerant composite cermet electrodes for solid oxide electrochemical cells

    DOEpatents

    Isenberg, Arnold O. (Pittsburgh, PA)

    1989-01-01

    An electrochemical apparatus is made containing an exterior electorde bonded to the exterior of a tubular, solid, oxygen ion conducting electrolyte where the electrolyte is also in contact with an interior electrode, said exterior electrode comprising particles of an electronic conductor contacting the electrolyte, where a ceramic metal oxide coating partially surrounds the particles and is bonded to the electrolyte, and where a coating of an ionic-electronic conductive material is attached to the ceramic metal oxide coating and to the exposed portions of the particles.

  14. Applications of advanced electrochemical techniques in the study of microbial fuel cells and corrosion protection by polymer coatings

    NASA Astrophysics Data System (ADS)

    Manohar, Aswin Karthik

    The results of a detailed evaluation of the properties of the anode and the cathode of a mediator-less microbial fuel cell (MFC) and the factors determining the power output of the MFC using different electrochemical techniques are presented in Chapter 1. In the MFC under investigation, the biocatalyst - Shewanella oneidensis MR-1 - oxidizes the fuel and transfers the electrons directly into the anode which consists of graphite felt. Oxygen is reduced at the cathode which consists of Pt-plated graphite felt. A proton exchange membrane separates the anode and the cathode compartments. The electrolyte was a PIPES buffer solution and lactate was used as the fuel. Separate tests were performed with the buffer solution containing lactate and with the buffer solution with lactate and MR-1 as anolytes. Electrochemical Impedance Spectroscopy (EIS) carried out at the open-circuit potential (OCP) has been used to determine the electrochemical properties of the anode and the cathode at different anolyte conditions. Cell voltage (V) -- current (I) curves were recorded using a potentiodynamic sweep between the open-circuit cell voltage and the short- circuit cell voltage. Power (P)-V curves were constructed from the recorded V-I data and the cell voltage, Vmax, at which the maximum power could be obtained, was determined. P- time (t) curves were obtained by applying Vmax or using a resistor between the anode and the cathode that would result in a similar cell voltage. Cyclic voltammograms (CV) were recorded for the anode for the different anolytes. Finally, anodic polarization curves were obtained for the anode with different anolytes and a cathodic polarization curve was recorded for the cathode. The internal resistance (Rint) of the MFC has been determined as a function of the cell voltage V using EIS for the MFC described above and a MFC in which stainless steel (SS) balls had been added to the anode compartment. The experimental values of Rint of the MFCs studied here are determined by the sum of the polarization resistance of the anode (Rap) and the cathode (Rcp), and therefore Rint depends on V. The ohmic contribution to the Rint was very small. It has been found that Rint decreased with decreasing cell voltage as the increasing current flow decreased R ap and Rcp. In the presence of MR-1, Rint was lower by a factor of about 100 than Rint of the MFC with buffer and lactate as anolyte. Additions of SS balls to the anode compartment produced a very large decrease of Rint. For the MFC containing SS balls in the anode compartment no significant further decrease of Rint could be observed when MR-1 was added to the anolyte. In Chapter 2, EIS has been used to determine the properties and stability of polymer coatings based on different chromate or chromate-free pretreatments and primers. Five sets of coated aluminum 2024 samples were exposed to 0.5N NaCl for a period of 31 days. Impedance spectra of the samples were measured during this period and the changes of the properties of the different coatings were studied as a function of time. From the analysis of the fit parameters of the impedance spectra, it was found that the corrosion protection of the coated samples depended on the type of primer used. The coating with the chromate based primer provided better corrosion protection than the coating with the chromate free primer. After 31 days of exposure, one sample from each set was scribed and exposed to 0.5N NaCl. The corrosion behavior of the scribed coatings was found to be dependent upon the type of pretreatment employed. The samples with the chromate conversion coating pretreatment showed better corrosion resistance in the scribed area than the samples that were treated by the trivalent chromium based method.

  15. Performance Evaluation of Electrochem's PEM Fuel Cell Power Plant for NASA's 2nd Generation Reusable Launch Vehicle

    NASA Technical Reports Server (NTRS)

    Kimble, Michael C.; Hoberecht, Mark

    2003-01-01

    NASA's Next Generation Launch Technology (NGLT) program is being developed to meet national needs for civil and commercial space access with goals of reducing the launch costs, increasing the reliability, and reducing the maintenance and operating costs. To this end, NASA is considering an all- electric capability for NGLT vehicles requiring advanced electrical power generation technology at a nominal 20 kW level with peak power capabilities six times the nominal power. The proton exchange membrane (PEM) fuel cell has been identified as a viable candidate to supply this electrical power; however, several technology aspects need to be assessed. Electrochem, Inc., under contract to NASA, has developed a breadboard power generator to address these technical issues with the goal of maximizing the system reliability while minimizing the cost and system complexity. This breadboard generator operates with dry hydrogen and oxygen gas using eductors to recirculate the gases eliminating gas humidification and blowers from the system. Except for a coolant pump, the system design incorporates passive components allowing the fuel cell to readily follow a duty cycle profile and that may operate at high 6:1 peak power levels for 30 second durations. Performance data of the fuel cell stack along with system performance is presented to highlight the benefits of the fuel cell stack design and system design for NGLT vehicles.

  16. Real-Time Detection of Telomerase Activity in Cancer Cells using a Label-Free Electrochemical Impedimetric Biosensing Microchip

    PubMed Central

    Cunci, Lisandro; Vargas, Marina Martinez; Cunci, Roman; Gomez-Moreno, Ramon; Perez, Ivan; Baerga-Ortiz, Abel; Gonzalez, Carlos I.; Cabrera, Carlos R.

    2014-01-01

    The enzyme telomerase is present in about 85% of human cancers which makes it not only a good target for cancer treatment but also an excellent marker for cancer detection. Using a single stranded DNA probe specific for telomerase binding and reverse transcription tethered to an interdigital gold electrode array surface, the chromosome protection provided by the telomerase was replicated and followed by Electrochemical Impedance Spectroscopy as an unlabeled biosensor. Using this system designed in-house, easy and affordable, impedance measurements were taken while incubating at 37 °C and promoting the probe elongation. This resulted in up to 14-fold increase in the charge transfer resistance when testing a telomerase-positive nuclear extract from Jurkat cells compared to the heat-inactivated telomerase-negative nuclear extract. The electron transfer process at the Au electrodes was studied before the elongation, at different times after the elongation, and after desorption of non-specific binding. PMID:25598969

  17. Simple and rapid fabrication of disposable carbon-based electrochemical cells using an electronic craft cutter for sensor and biosensor applications.

    PubMed

    Afonso, André S; Uliana, Carolina V; Martucci, Diego H; Faria, Ronaldo C

    2016-01-01

    This work describes the construction of an all-plastic disposable carbon-based electrochemical cell (DCell) using a simple procedure based on the use of a home cutter printer for prototyping and laminating. The cutter printer and adhesive vinyl films were used to produce three electrodes in an electrochemical cell layout, and a laminating process was then used to define the geometric area and insulate the electrodes. The DCell showed excellent performance in several applications including the determination of toxic metals in water samples, the immobilization of DNA and the detection of Salmonella. An unmodified DCell was applied for Pb and Cd detection in the range of 100-300ngmL(-1) with a limit of detection of 50 and 39ngmL(-1) for Cd and Pb, respectively. DNA was successfully immobilized on a DCell and used for studies of interaction between bisphenol A and DNA. The square wave voltammetry of a DNA modified DCell presented a guanine oxidation current 2.5 times greater after exposure of the electrode to bisphenol A and no current variation for the adenine moiety indicating that bisphenol A showed a preference for DNA interaction sites. A magneto-immunoassay was developed using a DCell for Salmonella detection in milk samples. The system presented a linear range from 100 to 700 cellsmL(-1) with a limit of detection of 100 cellsmL(-1) and good recovery values between 93% and 101% in milk samples, with no interference from Escherichia coli. Using the proposed method, hundreds of DCells can be assembled in less than two hours, at a material cost of less than US $0.02 per cell. The all-plastic disposable electrochemical cell developed was successfully applied as an electrochemical sensor and biosensor. The feasibility of the developed all-plastic disposable electrochemical cell was demonstrated in applications as both sensor and biosensor. PMID:26695279

  18. Treatment of Secondary Osteonecrosis of the Knee With Local Debridement and Osteoprogenitor Cell Grafting.

    PubMed

    Goodman, Stuart B; Hwang, Katherine L

    2015-11-01

    Secondary osteonecrosis of the knee (SOK) affects young individuals with chronic diseases and corticosteroid use. We report a series of young patients in whom the osteonecrotic lesion was openly debrided, and concentrated bone marrow osteoprogenitor cells (OPCs) harvested from the iliac crest were placed in the defect. Twelve patients (fourteen knees) have undergone debridement and grafting of distal femoral osteonecrotic lesions. Age at surgery averaged 23years. Follow-up averaged 5years. None of the patients have undergone further surgery, or were taking medications for ipsilateral knee pain. Knee Society Score and Knee Function Score averaged 87 and 85 respectively. The technique of open debridement and osteoprogenitor cell grafting for SOK is relatively simple, efficacious, has low morbidity, and does not preclude future interventions. PMID:26067706

  19. Examination of Early-Stage Chemistry of Secondary Organic Aerosol Formation using a Flow Cell

    NASA Astrophysics Data System (ADS)

    Pettibone, A. J.; McGivern, W. S.

    2010-12-01

    A laminar flow cell for the study of reactions of volatile organic compounds (VOCs) that lead to the formation of secondary organic aerosol (SOA) has been constructed. In the cell, reactions of VOC with oxygen are initiated by ultraviolet photolysis of alkyl iodides to form radical species typical of those produced from atmospheric hydrogen abstraction. The photolytic initiation of the reaction simplifies the oxidation mechanism relative to that of a typical chamber study. We propose a simplified mechanism that assumes no variation in vapor pressure for isomers having undergone equal numbers of isomerization reactions. In addition, treating isomers in terms of the number of oxygenated substitutions allows permutations to be enumerated that illustrate an increasing isomerization rate with increasing hydrocarbon chain length. In this system, significant growth of the particle distribution was observed when soot was used as a seed. Further studies will explore yields from different parent isomers as well as solubility and chemical identity of resulting oxidation products.

  20. Secondary Data Analytics of Aquaporin Expression Levels in Glioblastoma Stem-Like Cells

    PubMed Central

    Isokpehi, Raphael D; Wollenberg Valero, Katharina C; Graham, Barbara E; Pacurari, Maricica; Sims, Jennifer N; Udensi, Udensi K; Ndebele, Kenneth

    2015-01-01

    Glioblastoma is the most common brain tumor in adults in which recurrence has been attributed to the presence of cancer stem cells in a hypoxic microenvironment. On the basis of tumor formation in vivo and growth type in vitro, two published microarray gene expression profiling studies grouped nine glioblastoma stem-like (GS) cell lines into one of two groups: full (GSf) or restricted (GSr) stem-like phenotypes. Aquaporin-1 (AQP1) and aquaporin-4 (AQP4) are water transport proteins that are highly expressed in primary glial-derived tumors. However, the expression levels of AQP1 and AQP4 have not been previously described in a panel of 92 glioma samples. Therefore, we designed secondary data analytics methods to determine the expression levels of AQP1 and AQP4 in GS cell lines and glioblastoma neurospheres. Our investigation also included a total of 2,566 expression levels from 28 Affymetrix microarray probe sets encoding 13 human aquaporins (AQP0–AQP12); CXCR4 (the receptor for stromal cell derived factor-1 [SDF-1], a potential glioma stem cell therapeutic target]); and PROM1 (gene encoding CD133, the widely used glioma stem cell marker). Interactive visual representation designs for integrating phenotypic features and expression levels revealed that inverse expression levels of AQP1 and AQP4 correlate with distinct phenotypes in a set of cell lines grouped into full and restricted stem-like phenotypes. Discriminant function analysis further revealed that AQP1 and AQP4 expression are better predictors for tumor formation and growth types in glioblastoma stem-like cells than are CXCR4 and PROM1. Future investigations are needed to characterize the molecular mechanisms for inverse expression levels of AQP1 and AQP4 in the glioblastoma stem-like neurospheres. PMID:26279619

  1. Secondary Data Analytics of Aquaporin Expression Levels in Glioblastoma Stem-Like Cells.

    PubMed

    Isokpehi, Raphael D; Wollenberg Valero, Katharina C; Graham, Barbara E; Pacurari, Maricica; Sims, Jennifer N; Udensi, Udensi K; Ndebele, Kenneth

    2015-01-01

    Glioblastoma is the most common brain tumor in adults in which recurrence has been attributed to the presence of cancer stem cells in a hypoxic microenvironment. On the basis of tumor formation in vivo and growth type in vitro, two published microarray gene expression profiling studies grouped nine glioblastoma stem-like (GS) cell lines into one of two groups: full (GSf) or restricted (GSr) stem-like phenotypes. Aquaporin-1 (AQP1) and aquaporin-4 (AQP4) are water transport proteins that are highly expressed in primary glial-derived tumors. However, the expression levels of AQP1 and AQP4 have not been previously described in a panel of 92 glioma samples. Therefore, we designed secondary data analytics methods to determine the expression levels of AQP1 and AQP4 in GS cell lines and glioblastoma neurospheres. Our investigation also included a total of 2,566 expression levels from 28 Affymetrix microarray probe sets encoding 13 human aquaporins (AQP0-AQP12); CXCR4 (the receptor for stromal cell derived factor-1 [SDF-1], a potential glioma stem cell therapeutic target]); and PROM1 (gene encoding CD133, the widely used glioma stem cell marker). Interactive visual representation designs for integrating phenotypic features and expression levels revealed that inverse expression levels of AQP1 and AQP4 correlate with distinct phenotypes in a set of cell lines grouped into full and restricted stem-like phenotypes. Discriminant function analysis further revealed that AQP1 and AQP4 expression are better predictors for tumor formation and growth types in glioblastoma stem-like cells than are CXCR4 and PROM1. Future investigations are needed to characterize the molecular mechanisms for inverse expression levels of AQP1 and AQP4 in the glioblastoma stem-like neurospheres. PMID:26279619

  2. Method of forming a leak proof plasma sprayed interconnection layer on an electrode of an electrochemical cell

    DOEpatents

    Kuo, Lewis J. H. (Monroeville, PA); Vora, Shailesh D. (Monroeville, PA)

    1995-01-01

    A dense, substantially gas-tight, electrically conductive interconnection layer is formed on an electrode structure of an electrochemical cell by: (A) providing an electrode structure; (B) forming on a selected portion of the electrode surface, an interconnection layer having the general formula La.sub.1-x M.sub.x Cr.sub.1-y N.sub.y O.sub.3, where M is a dopant selected from the group of Ca, Sr, Ba, and mixtures thereof, and where N is a dopant selected from the group of Mg, Co, Ni, Al, and mixtures thereof, and where x and y are each independently about 0.075-0.25, by thermally spraying, preferably plasma arc spraying, a flux added interconnection spray powder, preferably agglomerated, the flux added powder comprising flux particles, preferably including dopant, preferably (CaO).sub.12. (Al.sub.2 O.sub.3).sub.7 flux particles including Ca and Al dopant, and LaCrO.sub.3 interconnection particles, preferably undoped LaCrO.sub.3, to form a dense and substantially gas-tight interconnection material bonded to the electrode structure by a single plasma spraying step; and, (C) heat treating the interconnection layer at from about 1200.degree. to 1350.degree. C. to further densify and heal the micro-cracks and macro-cracks of the thermally sprayed interconnection layer. The result is a substantially gas-tight, highly doped, electrically conductive interconnection material bonded to the electrode structure. The electrode structure can be an air electrode, and a solid electrolyte layer can be applied to the unselected portion of the air electrode, and further a fuel electrode can be applied to the solid electrolyte, to form an electrochemical cell for generation of electrical power.

  3. Method of forming a leak proof plasma sprayed interconnection layer on an electrode of an electrochemical cell

    DOEpatents

    Kuo, L.J.H.; Vora, S.D.

    1995-02-21

    A dense, substantially gas-tight, electrically conductive interconnection layer is formed on an electrode structure of an electrochemical cell by: (A) providing an electrode structure; (B) forming on a selected portion of the electrode surface, an interconnection layer having the general formula La{sub 1{minus}x}M{sub x}Cr{sub 1{minus}y}N{sub y}O{sub 3}, where M is a dopant selected from the group of Ca, Sr, Ba, and mixtures thereof, and where N is a dopant selected from the group of Mg, Co, Ni, Al, and mixtures thereof, and where x and y are each independently about 0.075--0.25, by thermally spraying, preferably plasma arc spraying, a flux added interconnection spray powder, preferably agglomerated, the flux added powder comprising flux particles, preferably including dopant, preferably (CaO){sub 12}(Al{sub 2}O{sub 3}){sub 7} flux particles including Ca and Al dopant, and LaCrO{sub 3} interconnection particles, preferably undoped LaCrO{sub 3}, to form a dense and substantially gas-tight interconnection material bonded to the electrode structure by a single plasma spraying step; and (C) heat treating the interconnection layer at from about 1,200 to 1,350 C to further densify and heal the micro-cracks and macro-cracks of the thermally sprayed interconnection layer. The result is a substantially gas-tight, highly doped, electrically conductive interconnection material bonded to the electrode structure. The electrode structure can be an air electrode, and a solid electrolyte layer can be applied to the unselected portion of the air electrode, and further a fuel electrode can be applied to the solid electrolyte, to form an electrochemical cell for generation of electrical power. 4 figs.

  4. In-situ short-circuit protection system and method for high-energy electrochemical cells

    DOEpatents

    Gauthier, Michel (La Prairie, CA); Domroese, Michael K. (South St. Paul, MN); Hoffman, Joseph A. (Minneapolis, MN); Lindeman, David D. (Hudson, WI); Noel, Joseph-Robert-Gaetan (St-Hubert, CA); Radewald, Vern E. (Austin, TX); Rouillard, Jean (Saint-Luc, CA); Rouillard, Roger (Beloeil, CA); Shiota, Toshimi (St. Bruno, CA); Trice, Jennifer L. (Eagan, MN)

    2003-04-15

    An in-situ thermal management system for an energy storage device. The energy storage device includes a plurality of energy storage cells each being coupled in parallel to common positive and negative connections. Each of the energy storage cells, in accordance with the cell's technology, dimensions, and thermal/electrical properties, is configured to have a ratio of energy content-to-contact surface area such that thermal energy produced by a short-circuit in a particular cell is conducted to a cell adjacent the particular cell so as to prevent the temperature of the particular cell from exceeding a breakdown temperature. In one embodiment, a fuse is coupled in series with each of a number of energy storage cells. The fuses are activated by a current spike capacitively produced by a cell upon occurrence of a short-circuit in the cell, thereby electrically isolating the short-circuited cell from the common positive and negative connections.

  5. In-situ short circuit protection system and method for high-energy electrochemical cells

    DOEpatents

    Gauthier, Michel (La Prairie, CA); Domroese, Michael K. (South St. Paul, MN); Hoffman, Joseph A. (Minneapolis, MN); Lindeman, David D. (Hudson, WI); Noel, Joseph-Robert-Gaetan (St-Hubert, CA); Radewald, Vern E. (Austin, TX); Rouillard, Jean (Saint-Luc, CA); Rouillard, Roger (Beloeil, CA); Shiota, Toshimi (St. Bruno, CA); Trice, Jennifer L. (Eagan, MN)

    2000-01-01

    An in-situ thermal management system for an energy storage device. The energy storage device includes a plurality of energy storage cells each being coupled in parallel to common positive and negative connections. Each of the energy storage cells, in accordance with the cell's technology, dimensions, and thermal/electrical properties, is configured to have a ratio of energy content-to-contact surface area such that thermal energy produced by a short-circuit in a particular cell is conducted to a cell adjacent the particular cell so as to prevent the temperature of the particular cell from exceeding a breakdown temperature. In one embodiment, a fuse is coupled in series with each of a number of energy storage cells. The fuses are activated by a current spike capacitively produced by a cell upon occurrence of a short-circuit in the cell, thereby electrically isolating the short-circuited cell from the common positive and negative connections.

  6. Capped mRNAs with reduced secondary structure can function in extracts from poliovirus-infected cells

    SciTech Connect

    Sonenberg, N.; Guertin, D.; Lee, K.A.W.

    1982-12-01

    Extracts form poliovirus-infected HeLa cells were used to study ribosome binding of native and denatured reovirus mRNAs and translation of capped mRNAs with different degrees of secondary structure. Here, the authors demonstrate that ribosomes in extracts from poliovirus-infected cells could form initiation complexes with denatured reovirus mRNA, in contrast to their inability to bind native reovirus mRNA. Furthermore, the capped alfalfa mosiac virus 4 RNA, which is most probable devoid of stable secondary structure at its 5' end, could be translated at much higher efficiency than could other capped mRNAs in extracts from poliovirus-infected cells.

  7. The overall structure of the human lens is one of succes-sive generations of secondary fiber cells stratified chrono-

    E-print Network

    Hammock, Bruce D.

    Purpose: Human eye lenses contain cells that persist from embryonic development. These unique, highlyThe overall structure of the human lens is one of succes- sive generations of secondary fiber cells turnover in the water-soluble protein of the adult human lens Daniel N. Stewart,1 Jozsef Lango,1 Krishnan P

  8. Electro-triggering and electrochemical monitoring of dopamine exocytosis from a single cell by using ultrathin electrodes based on Au nanowires.

    PubMed

    Kang, Mijeong; Yoo, Seung Min; Gwak, Raekeun; Eom, Gayoung; Kim, Jihwan; Lee, Sang Yup; Kim, Bongsoo

    2015-12-17

    A sophisticated set of an Au nanowire (NW) stimulator-Au NW detector system is developed for electrical cell stimulation and electrochemical analysis of subsequent exocytosis with very high spatial resolution. Dopamine release from a rat pheochromocytoma cell is more stimulated by a more negative voltage pulse. This system could help to improve the therapeutic efficacy of electrotherapies by providing valuable information on their healing mechanism. PMID:26645731

  9. Secondary lithium batteries for space applications

    NASA Technical Reports Server (NTRS)

    Carter, B.; Khanna, S. K.; Yen, S. P. S.; Shen, D.; Somoano, R. B.

    1981-01-01

    Secondary lithium cells which use a LiAsF6-2-Me-THF electrolyte and a TiS2 intercalatable cathode exhibit encouraging cycle life at ambient temperature. Electrochemical and surface analytical studies indicate that the electrolyte is unstable in the presence of metallic lithium, leading to the formation of a lithium passivating film composed of lithium arsenic oxyfluorides and lithium fluorsilicates. The lithium cyclability remains as the most important problem to solve. Different electrolyte solvents, such as sulfolane, exhibit promising characteristics but lead to new compatibility problems with the other cell component materials.

  10. Electrochemical Analysis of Neurotransmitters

    NASA Astrophysics Data System (ADS)

    Bucher, Elizabeth S.; Wightman, R. Mark

    2015-07-01

    Chemical signaling through the release of neurotransmitters into the extracellular space is the primary means of communication between neurons. More than four decades ago, Ralph Adams and his colleagues realized the utility of electrochemical methods for the study of easily oxidizable neurotransmitters, such as dopamine, norepinephrine, and serotonin and their metabolites. Today, electrochemical techniques are frequently coupled to microelectrodes to enable spatially resolved recordings of rapid neurotransmitter dynamics in a variety of biological preparations spanning from single cells to the intact brain of behaving animals. In this review, we provide a basic overview of the principles underlying constant-potential amperometry and fast-scan cyclic voltammetry, the most commonly employed electrochemical techniques, and the general application of these methods to the study of neurotransmission. We thereafter discuss several recent developments in sensor design and experimental methodology that are challenging the current limitations defining the application of electrochemical methods to neurotransmitter measurements.

  11. Fabrication of advanced electrochemical energy materials using sol-gel processing techniques

    NASA Technical Reports Server (NTRS)

    Chu, C. T.; Chu, Jay; Zheng, Haixing

    1995-01-01

    Advanced materials play an important role in electrochemical energy devices such as batteries, fuel cells, and electrochemical capacitors. They are being used as both electrodes and electrolytes. Sol-gel processing is a versatile solution technique used in fabrication of ceramic materials with tailored stoichiometry, microstructure, and properties. The application of sol-gel processing in the fabrication of advanced electrochemical energy materials will be presented. The potentials of sol-gel derived materials for electrochemical energy applications will be discussed along with some examples of successful applications. Sol-gel derived metal oxide electrode materials such as V2O5 cathodes have been demonstrated in solid-slate thin film batteries; solid electrolytes materials such as beta-alumina for advanced secondary batteries had been prepared by the sol-gel technique long time ago; and high surface area transition metal compounds for capacitive energy storage applications can also be synthesized with this method.

  12. Clonal Architecture of Secondary Acute Myeloid Leukemia Defined by Single-Cell Sequencing

    PubMed Central

    Hughes, Andrew E. O.; Magrini, Vincent; Demeter, Ryan; Miller, Christopher A.; Fulton, Robert; Fulton, Lucinda L.; Eades, William C.; Elliott, Kevin; Heath, Sharon; Westervelt, Peter; Ding, Li; Conrad, Donald F.; White, Brian S.; Shao, Jin; Link, Daniel C.; DiPersio, John F.; Mardis, Elaine R.; Wilson, Richard K.; Ley, Timothy J.; Walter, Matthew J.; Graubert, Timothy A.

    2014-01-01

    Next-generation sequencing has been used to infer the clonality of heterogeneous tumor samples. These analyses yield specific predictions—the population frequency of individual clones, their genetic composition, and their evolutionary relationships—which we set out to test by sequencing individual cells from three subjects diagnosed with secondary acute myeloid leukemia, each of whom had been previously characterized by whole genome sequencing of unfractionated tumor samples. Single-cell mutation profiling strongly supported the clonal architecture implied by the analysis of bulk material. In addition, it resolved the clonal assignment of single nucleotide variants that had been initially ambiguous and identified areas of previously unappreciated complexity. Accordingly, we find that many of the key assumptions underlying the analysis of tumor clonality by deep sequencing of unfractionated material are valid. Furthermore, we illustrate a single-cell sequencing strategy for interrogating the clonal relationships among known variants that is cost-effective, scalable, and adaptable to the analysis of both hematopoietic and solid tumors, or any heterogeneous population of cells. PMID:25010716

  13. Engineering secondary metabolism in maize cells by ectopic expression of transcription factors

    PubMed Central

    Grotewold, E; Chamberlin, M; Snook, M; Siame, B; Butler, L; Swenson, J; Maddock, S; Clair, GS; Bowen, B

    1998-01-01

    Manipulation of plant natural product biosynthesis through genetic engineering is an attractive but technically challenging goal. Here, we demonstrate that different secondary metabolites can be produced in cultured maize cells by ectopic expression of the appropriate regulatory genes. Cell lines engineered to express the maize transcriptional activators C1 and R accumulate two cyanidin derivatives, which are similar to the predominant anthocyanin found in differentiated plant tissues. In contrast, cell lines that express P accumulate various 3-deoxy flavonoids. Unexpectedly, P-expressing cells in culture also accumulate phenylpropanoids and green fluorescent compounds that are targeted to different subcellular compartments. Two endogenous biosynthetic genes (c2 and a1, encoding chalcone synthase and flavanone/dihydroflavonol reductase, respectively) are independently activated by ectopic expression of either P or C1/R, and there is a dose-response relationship between the transcript level of P and the degree to which c2 or a1 is expressed. Our results support a simple model showing how the gene encoding P may act as a quantitative trait locus controlling insecticidal C-glycosyl flavone level in maize silks, and they suggest how p1 might confer a selective advantage against insect predation in maize. PMID:9596632

  14. Secondary cell with orthorhombic alkali metal/manganese oxide phase active cathode material

    DOEpatents

    Doeff, Marca M. (Hayward, CA); Peng, Marcus Y. (Cupertino, CA); Ma, Yanping (Albany, CA); Visco, Steven J. (Berkeley, CA); DeJonghe, Lutgard C. (Lafayette, CA)

    1996-01-01

    An alkali metal manganese oxide secondary cell is disclosed which can provide a high rate of discharge, good cycling capabilities, good stability of the cathode material, high specific energy (energy per unit of weight) and high energy density (energy per unit volume). The active material in the anode is an alkali metal and the active material in the cathode comprises an orthorhombic alkali metal manganese oxide which undergoes intercalation and deintercalation without a change in phase, resulting in a substantially linear change in voltage with change in the state of charge of the cell. The active material in the cathode is an orthorhombic structure having the formula M.sub.x Z.sub.y Mn.sub.(1-y) O.sub.2, where M is an alkali metal; Z is a metal capable of substituting for manganese in the orthorhombic structure such as iron, cobalt or titanium; x ranges from about 0.2 in the fully charged state to about 0.75 in the fully discharged state, and y ranges from 0 to 60 atomic %. Preferably, the cell is constructed with a solid electrolyte, but a liquid or gelatinous electrolyte may also be used in the cell.

  15. Secondary cell with orthorhombic alkali metal/manganese oxide phase active cathode material

    DOEpatents

    Doeff, M.M.; Peng, M.Y.; Ma, Y.; Visco, S.J.; DeJonghe, L.C.

    1996-09-24

    An alkali metal manganese oxide secondary cell is disclosed which can provide a high rate of discharge, good cycling capabilities, good stability of the cathode material, high specific energy (energy per unit of weight) and high energy density (energy per unit volume). The active material in the anode is an alkali metal and the active material in the cathode comprises an orthorhombic alkali metal manganese oxide which undergoes intercalation and deintercalation without a change in phase, resulting in a substantially linear change in voltage with change in the state of charge of the cell. The active material in the cathode is an orthorhombic structure having the formula M{sub x}Z{sub y}Mn{sub (1{minus}y)}O{sub 2}, where M is an alkali metal; Z is a metal capable of substituting for manganese in the orthorhombic structure such as iron, cobalt or titanium; x ranges from about 0.2 in the fully charged state to about 0.75 in the fully discharged state, and y ranges from 0 to 60 atomic %. Preferably, the cell is constructed with a solid electrolyte, but a liquid or gelatinous electrolyte may also be used in the cell. 11 figs.

  16. Electrochemical impedance spectroscopy study on polymerization of L-lysine on electrode surface and its application for immobilization and detection of suspension cells.

    PubMed

    Huang, Baozhen; Jia, Ningming; Chen, Lina; Tan, Liang; Yao, Shouzhuo

    2014-07-15

    Poly-L-lysine (PLL), which has been employed as a conductive polymer in the construction of some electrochemical sensors, can be prepared using L-lysine by cyclic voltammetry (CV) with a wide potential range. However, the presented explanation and description about its polymerization mechanism seems oversimplified because the self-reaction of electrode and the electrolysis of solvent at high potential are ignored. This work presents an intensive investigation on the relevant reactions during the process of PLL-polymerization using CV, X-ray photoelectron spectroscopy, Fourier transform-infrared spectroscopy, and electrochemical impedance spectroscopy. At a higher positive potential, the transfer from lysine molecules to cation radicals and the polymerization reaction on the glassy carbon electrode (GCE) could be achieved, accompanied by the activation of GCE, the formation of oxygen-containing functional groups, and the generation of oxygen derived from the oxidation of water. The adsorbed oxygen had a seriously negative effect on the formation of PLL unless it suffered reduction at a lower negative potential. The charge transfer through the electrochemical polymerized PLL film was seriously hindered by the immobilization of suspension cells due to the electrostatic interaction. The charge-transfer resistance difference (?R(ct)) was increased with the enhancement of the cell number (N(cells)) and the 1/?R(ct) value displayed a linear response with 1/N(cells) in the range of 5.0 × 10(2)-1.0 × 10(5) cells with a detection limit of 180 cells estimated at a signal-to-noise ratio of 3. A sensitive electrochemical sensor for the quantitative detection of suspension cells was developed. PMID:24939429

  17. Parenchyma cell respiration and survival in secondary xylem: does metabolic activity decline with cell age?

    PubMed

    Spicer, R; Holbrook, N M

    2007-08-01

    Sapwood respiration often declines towards the sapwood/heartwood boundary, but it is not known if parenchyma metabolic activity declines with cell age. We measured sapwood respiration in five temperate species (sapwood age range of 5-64 years) and expressed respiration on a live cell basis by quantifying living parenchyma. We found no effect of parenchyma age on respiration in two conifers (Pinus strobus, Tsuga canadensis), both of which had significant amounts of dead parenchyma in the sapwood. In angiosperms (Acer rubrum, Fraxinus americana, Quercus rubra), both bulk tissue and live cell respiration were reduced by about one-half in the oldest relative to the youngest sapwood, and all sapwood parenchyma remained alive. Conifers and angiosperms had similar bulk tissue respiration despite a smaller proportion of parenchyma in conifers (5% versus 15-25% in angiosperms), such that conifer parenchyma respired at rates about three times those of angiosperms. The fact that 5-year-old parenchyma cells respired at the same rate as 25-year-old cells in conifers suggests that there is no inherent or intrinsic decline in respiration as a result of cellular ageing. In contrast, it is not known whether differences observed in cellular respiration rates of angiosperms are a function of age per se, or whether active regulation of metabolic rate or positional effects (e.g. proximity to resources and/or hormones) could be the cause of reduced respiration in older sapwood. PMID:17617821

  18. Heteromannan and Heteroxylan Cell Wall Polysaccharides Display Different Dynamics During the Elongation and Secondary Cell Wall Deposition Phases of Cotton Fiber Cell Development

    PubMed Central

    Hernandez-Gomez, Mercedes C.; Runavot, Jean-Luc; Guo, Xiaoyuan; Bourot, Stéphane; Benians, Thomas A.S.; Willats, William G.T.; Meulewaeter, Frank; Knox, J. Paul

    2015-01-01

    The roles of non-cellulosic polysaccharides in cotton fiber development are poorly understood. Combining glycan microarrays and in situ analyses with monoclonal antibodies, polysaccharide linkage analyses and transcript profiling, the occurrence of heteromannan and heteroxylan polysaccharides and related genes in developing and mature cotton (Gossypium spp.) fibers has been determined. Comparative analyses on cotton fibers at selected days post-anthesis indicate different temporal and spatial regulation of heteromannan and heteroxylan during fiber development. The LM21 heteromannan epitope was more abundant during the fiber elongation phase and localized mainly in the primary cell wall. In contrast, the AX1 heteroxylan epitope occurred at the transition phase and during secondary cell wall deposition, and localized in both the primary and the secondary cell walls of the cotton fiber. These developmental dynamics were supported by transcript profiling of biosynthetic genes. Whereas our data suggest a role for heteromannan in fiber elongation, heteroxylan is likely to be involved in the regulation of cellulose deposition of secondary cell walls. In addition, the relative abundance of these epitopes during fiber development varied between cotton lines with contrasting fiber characteristics from four species (G. hirsutum, G. barbadense, G. arboreum and G. herbaceum), suggesting that these non-cellulosic polysaccharides may be involved in determining final fiber quality and suitability for industrial processing. PMID:26187898

  19. Preparation of Pt-Co nanoparticles by galvanostatic pulse electrochemical codeposition on in situ electrochemical reduced graphene nanoplates based carbon paper electrode for oxygen reduction reaction in proton exchange membrane fuel cell

    NASA Astrophysics Data System (ADS)

    Yaldagard, Maryam; Seghatoleslami, Naser; Jahanshahi, Mohsen

    2014-10-01

    Nanocomposite films of Pt-Co nanoparticles deposited on graphene nanoplate based gas diffusion layer electrode are fabricated via an electrochemical route involving a series of electrochemical process. Pt-Co nanoparticles of 11.37 nm in average size are prepared by galvanostatic codeposition in 0.5 M NaCl at PH of 2.5 at 300 mA cm-2 on the surface of in situ reduced graphene nanoplates on carbon paper. The topographical features, structure, morphology and composition of the prepared film samples are characterized by Atomic Force microscopy, Raman Spectroscopy, FTIR analysis, X-ray Diffraction, FESEM and EDS. At the same time, the catalytic activities of prepared electrodes for the oxygen reduction reaction are evaluated through cyclic voltammetry, linear sweep voltammetry and chronoamperometry and electrochemical impedance spectroscopy measurements. Raman spectroscopy measurements confirmed the graphitic structure of the produced graphene nanoplates. The nanoparticles in the film were observed to be uniform spherical objects and well distributed. Catalytic properties of Pt-Co/GNP/GDL electrode were compared with Pt/C/GDL using half cell polarization measurements based on both mass activity and specific activity. The as prepared Pt-Co/GNP/GDL electrode exhibits high catalytic activity for the ORR, which may be attributed to structural changes caused by alloying and the high specific surface area of graphene nanoplates catalyst support. The mass activity peak current is found to be as high as 728.25 mA mgPt-1.

  20. Isolation of a novel cell wall architecture mutant of rice with defective Arabidopsis COBL4 ortholog BC1 required for regulated deposition of secondary cell wall components.

    PubMed

    Sato, Kanna; Suzuki, Ryu; Nishikubo, Nobuyuki; Takenouchi, Sachi; Ito, Sachiko; Nakano, Yoshimi; Nakaba, Satoshi; Sano, Yuzou; Funada, Ryo; Kajita, Shinya; Kitano, Hidemi; Katayama, Yoshihiro

    2010-06-01

    The plant secondary cell wall is a highly ordered structure composed of various polysaccharides, phenolic components and proteins. Its coordinated regulation of a number of complex metabolic pathways and assembly has not been resolved. To understand the molecular mechanisms that regulate secondary cell wall synthesis, we isolated a novel rice mutant, cell wall architecture1 (cwa1), that exhibits an irregular thickening pattern in the secondary cell wall of sclerenchyma, as well as culm brittleness and reduced cellulose content in mature internodes. Light and transmission electron microscopy revealed that the cwa1 mutant plant has regions of local aggregation in the secondary cell walls of the cortical fibers in its internodes, showing uneven thickness. Ultraviolet microscopic observation indicated that localization of cell wall phenolic components was perturbed and that these components abundantly deposited at the aggregated cell wall regions in sclerenchyma. Therefore, regulation of deposition and assembly of secondary cell wall materials, i.e. phenolic components, appear to be disturbed by mutation of the cwa1 gene. Genetic analysis showed that cwa1 is allelic to brittle culm1 (bc1), which encodes the glycosylphosphatidylinositol-anchored COBRA-like protein specifically in plants. BC1 is known as a regulator that controls the culm mechanical strength and cellulose content in the secondary cell walls of sclerenchyma, but the precise function of BC1 has not been resolved. Our results suggest that CWA1/BC1 has an essential role in assembling cell wall constituents at their appropriate sites, thereby enabling synthesis of solid and flexible internodes in rice. PMID:20424856

  1. Molecule-Specific Imaging Analysis of Carcinogens in Breast Cancer Cells Using Time-of-Flight Secondary Ion Mass Spectrometry

    SciTech Connect

    Quong, J N; Knize, M G; Kulp, K S; Wu, K J

    2003-08-19

    Imaging time-of-flight secondary ion mass spectrometry (TOF-SIMS) is used to study the localization of heterocyclic amines in MCF7 line of human breast cancer cells. The detection sensitivities of a model rodent mutagen, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) were determined. Following an established criteria for the determination of status of freeze-fracture cells, the distribution of PhIP in the MCF7 cells are reported.

  2. B-cell lymphoma with plasmacytoid differentiation, atypical cytoplasmic inclusions, and secondary leukemia in a dog.

    PubMed

    Kol, A; Christopher, M M; Skorupski, K A; Tokarz, D; Vernau, W

    2013-03-01

    A 7-year-old male castrated Jack Russell Terrier was presented to the oncology service at the University of California-Davis Veterinary Medical Teaching Hospital for evaluation of suspected lymphoma. The dog had several enlarged lymph nodes and moderate lymphocytosis. Aspirates of an enlarged inguinal lymph node contained a bimorphic population of large immature lymphocytes and smaller cells with plasmacytoid features. Both cell types often contained a single large cytoplasmic inclusion that varied from clear to pale pink to sky blue. Cytologic changes were interpreted as most consistent with lymphoid neoplasia. Based on the predominantly mature cell morphology and some morphologic heterogeneity, the peripheral lymphocytosis was interpreted as most likely reactive in nature. However, the immunophenotype of the cells (CD20+, CD21+, CD79a+, MUM-1+, and MHCII+) and clonality assays showed that tissue and blood lymphocytes were neoplastic B cells with clonal identity despite their different morphologic appearances. The cytoplasmic inclusions were positive with periodic acid-Schiff and were immunoreactive for IgM and IgG. By transmission electron microscopy, inclusions consisted of aberrant rough endoplasmic reticulum; a few small Russell bodies were also noted. A final diagnosis of high-grade B-cell lymphoma with plasmacytoid differentiation, atypical cytoplasmic inclusions, and secondary leukemia was made. Chemotherapy was initiated, but the dog was euthanized due to severe and uncontrolled seizures 9 months after the initial diagnosis. This case extends the morphologic repertoire of canine plasmacytoid neoplasms and emphasizes their continuum with multicentric lymphoma. This case also demonstrates the need for advanced diagnostic techniques in establishing blood involvement in lymphoma in some instances. PMID:23205858

  3. Space Electrochemical Research and Technology

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The proceedings of NASA's third Space Electrochemical Research and Technology (SERT) conference are presented. The objective of the conference was to assess the present status and general thrust of research and development in those areas of electrochemical technology required to enable NASA missions in the next century. The conference provided a forum for the exchange of ideas and opinions of those actively involved in the field, in order to define new opportunities for the application of electrochemical processes in future NASA missions. Papers were presented in three technical areas: the electrochemical interface, the next generation in aerospace batteries and fuel cells, and electrochemistry for nonenergy storage applications.

  4. Granulosa cell tumor associated with secondary amenorrhea and serum luteinizing hormone elevation.

    PubMed

    Nasu, Kaei; Fukuda, Junichiro; Yoshimatsu, Jun; Takai, Noriyuki; Kashima, Kenji; Narahara, Hisashi

    2007-06-01

    Adult granulosa cell tumors (GCTs) are the most common type of ovarian sex cord tumors. Menstrual irregularity, menorrhagia, or even secondary amenorrhea is frequently observed in premenopausal women bearing GCTs with hormonal activity. We report herein a case of GCT in a patient presenting with secondary amenorrhea and serum luteinizing hormone elevation. A 28-year-old primigravid Japanese woman was admitted complaining of secondary amenorrhea of 2 years' duration. Pelvic examination, transvaginal ultrasonography, and magnetic resonance imaging demonstrated a left ovarian tumor 4 cm in diameter. Serum hormone assays revealed a follicle-stimulating hormone level of 4.8 mIU/ml, luteinizing hormone (LH) of 35.8 mIU/ml, estradiol of 24 pg/ml, progesterone of 1.6 ng/ml, and testosterone of 40 ng/dl. A left salpingo-oophorectomy was performed. The tumor was diagnosed as an adult-type GCT stage IIb (FIGO [International Federation of Obstetricians and Gynecologists], 1988). Spontaneous menstruation occurred soon after the surgery. Serum levels of LH also decreased to normal levels and showed cyclic changes during the menstrual cycle. Subsequently, the patient conceived and delivered a healthy female baby. The tumor recurred in the pelvis 50 months after the initial conservative surgery, with elevated serum LH levels of 36.0 mIU/ml and amenorrhea. The patient was treated by hysterectomy, right salpingo-oophorectomy, omentectomy, paraaortic and pelvic lymphadenectomy, and low anterior resection of the recto-sigmoid colon. Her hormone levels progressed to the postmenopausal state after this surgery. Although LH elevation in patients with GCT is rare and its mechanism is unknown, monitoring of serum LH may provide an additional tumor marker after conservative surgery in such patients. PMID:17566848

  5. Tailoring carrier injection efficiency to improve the carrier balance of solid-state light-emitting electrochemical cells.

    PubMed

    Liao, Chih-Teng; Chen, Hsiao-Fan; Su, Hai-Ching; Wong, Ken-Tsung

    2012-07-21

    We study the influence of the carrier injection efficiency on the performance of light-emitting electrochemical cells (LECs) based on a hole-preferred transporting cationic transition metal complex (CTMC) [Ir(dfppz)(2)(dtb-bpy)](+)(PF(6)(-)) (complex 1) and an electron-preferred transporting CTMC [Ir(ppy)(2)(dasb)](+)(PF(6)(-)) (complex 2) (where dfppz is 1-(2,4-difluorophenyl) pyrazole, dtb-bpy is 4,4'-di(tert-butyl)-2,2'-bipyridine, ppy is 2-phenylpyridine and dasb is 4,5-diaza-9,9'-spirobifluorene). Experimental results show that even with electrochemically doped layers, the ohmic contacts for carrier injection could be formed only when the carrier injection barriers were relatively low. Thus, adding carrier injection layers in LECs with relatively high carrier injection barriers would affect carrier balance and thus would result in altered device efficiency. Comparison of the device characteristics of LECs based on complex 1 and 2 in various device structures suggests that the carrier injection efficiency of CTMC-based LECs should be modified according to the carrier transporting characteristics of CTMCs to optimize device efficiency. Hole-preferred transporting CTMCs should be combined with an LEC structure with a relatively high electron injection efficiency, while a relatively high hole injection efficiency would be required for LECs based on electron-preferred transporting CTMCs. Since the tailored carrier injection efficiency compensates for the unbalanced carrier transporting properties of the emissive layer, the carrier recombination zone would be located near the center of the emissive layer and exciton quenching near the electrodes would be significantly mitigated, rendering an improved device efficiency approaching the upper limit expected from the photoluminescence quantum yield of the emissive layer and the optical outcoupling efficiency from a typical layered light-emitting device structure. PMID:22684499

  6. Apparatus for combinatorial screening of electrochemical materials

    DOEpatents

    A high throughput combinatorial screening method and apparatus for the evaluation of electrochemical materials using a single voltage source (2) is disclosed wherein temperature changes arising from the application of an electrical load to a cell array (1) are used to evaluate the relative electrochemical efficiency of the materials comprising the array. The apparatus may include an array of electrochemical cells (1) that are connected to each other in parallel or in series, an electronic load (2) for applying a voltage or current to the electrochemical cells (1), and a device (3), external to the cells, for monitoring the relative temperature of each cell when the load is applied.

    2009-12-15

    A high throughput combinatorial screening method and apparatus for the evaluation of electrochemical materials using a single voltage source (2) is disclosed wherein temperature changes arising from the application of an electrical load to a cell array (1) are used to evaluate the relative electrochemical efficiency of the materials comprising the array. The apparatus may include an array of electrochemical cells (1) that are connected to each other in parallel or in series, an electronic load (2) for applying a voltage or current to the electrochemical cells (1), and a device (3), external to the cells, for monitoring the relative temperature of each cell when the load is applied.

  7. PD-1 Impairs Secondary Effector Lung CD8+ T Cells during Respiratory Virus Reinfection

    PubMed Central

    Erickson, John J.; Rogers, Meredith C.; Hastings, Andrew K.; Tollefson, Sharon J.; Williams, John V.

    2014-01-01

    Reinfections with respiratory viruses are common and cause significant clinical illness, yet precise mechanisms governing this susceptibility are ill defined. Lung Ag-specific CD8+ T cells (TCD8) are impaired during acute viral lower respiratory infection by the inhibitory receptor PD-1. To determine if PD-1 contributes to recurrent infection, we first established a model of reinfection by challenging B cell-deficient mice with human metapneumovirus (HMPV) several weeks after primary infection, and found that HMPV replicated to high titers in the lungs. A robust secondary effector lung TCD8 response was generated during reinfection, but these cells were more impaired and more highly expressed the inhibitory receptors PD-1, LAG-3, and 2B4 than primary TCD8. In vitro blockade demonstrated that PD-1 was the most dominant inhibitory receptor early after reinfection. In vivo therapeutic PD-1 blockade during HMPV reinfection restored lung TCD8 effector functions (i.e. degranulation and cytokine production) and enhanced viral clearance. PD-1 also limited the protective efficacy of HMPV epitope-specific peptide vaccination and impaired lung TCD8 during heterotypic influenza virus challenge infection. Our results indicate that PD-1 signaling may contribute to respiratory virus reinfection and evasion of vaccine-elicited immune responses. These results have important implications for the design of effective vaccines against respiratory viruses. PMID:25339663

  8. Life testing of secondary silver-zinc cells for the orbiting maneuvering vehicle

    NASA Technical Reports Server (NTRS)

    Brewer, Jeffrey C.; Doreswamy, Rajiv; Jackson, Lorna G.

    1990-01-01

    Over the past 5 years, extensive testing has been performed at the Marshall Space Flight Center (MSFC) on a variety of secondary (rechargeable) silver-zinc (Ag-Zn) cells for the Orbital Maneuvering Vehicle (OMV). The first tests performed were to determine the feasibility of using such a cell in a long-life (18-month), low-Earth-orbit (LEO) application. Results from these tests were promising, so testing continued with a 250-Ah cell that was specifically designed for this type of application. Once again, results from the tests were promising. Following a review of the data from these previous tests, slight modifications to the 250-Ah design were necessary to alleviate problem areas. Currently, MSFC is testing a 350-Ah design that has incorporated these changes and is the baseline design for the OMV. This test began in mid-November, 1989, and will be complete in the spring of 1991, barring any substantial offline time. A report is presented on the preliminary results from the first few months of this test and they are compared to results obtained in previous tests done at MFSC.

  9. Method for producing a secondary lithium cell comprising a heat-sensitive protective mechanism

    DOEpatents

    Ullrich, Matthias (Kelkheim, DE); Bechtold, Dieter (Bad Vilbel, DE); Rabenstein, Heinrich (Frankfurt, DE); Brohm, Thomas (Kelkheim, DE)

    2003-01-01

    A method for producing a secondary lithium cell which has at least one lithium-cycling negative electrode, at least one lithium-intercalating positive electrode, at least one separator disposed between the positive and the negative electrode, and a nonaqueous lithium ion-conducting electrolyte. The method is carried out by the electrodes and/or the separator being coated, by means of electrostatic powder coating, with wax particles which are insoluble in the electrolyte and have a melting temperature of from about 50 to about 150 .degree. C. and a mean particle size of from about 6 to about 20 .mu.m, the amount of wax being between about 0.5 and about 2.5 mg/cm.sup.2 of electrode area.

  10. Synthesis and electrochemical properties of LiV3O8/PAn composite as a cathode material for lithium secondary batteries

    NASA Astrophysics Data System (ADS)

    Xie, Ling-Ling; Cao, Xiao-Yu; Zhang, Li-Xu; Dai, Zhong-Xu; Qu, Ling-Bo

    2013-03-01

    A LiV3O8/polyaniline (PAn) composite was prepared by the in-situ polymerization method assisted by sodium dodecyl sulfate and ammonium persulfate. The as-prepared powders were investigated by XRD, SEM, and galvanostatic discharge/charge analysis. It was found that the introduction of PAn to LiV3O8 can effectively buffer the mechanical stress and restrain the number of phase changes of composite material during the electrochemical cycling. Compared with pristine LiV3O8, LiV3O8/PAn composite maintains a reversible capacity of 212.1 mAh g-1 at the current density of 30 mA g-1 after 50 cycles, approximately 22.6%, much higher than the former.

  11. Position dependent analysis of membrane electrode assembly degradation of a direct methanol fuel cell via electrochemical impedance spectroscopy

    NASA Astrophysics Data System (ADS)

    Hartmann, Peter; Zamel, Nada; Gerteisen, Dietmar

    2013-11-01

    The performance of a direct methanol fuel cell MEA degraded during an operational period of more than 3000 h in a stack is locally examined using electrochemical impedance spectroscopy. Therefore, after disassembling the MEA is cut into small pieces and analyzed in a 1 cm2 test cell. Using a reference electrode, we were capable of measuring the anode and cathode spectra separately. The spectra of the segments at different positions do not follow a specified trend from methanol inlet to outlet of the stack flow field. The anode spectra were analyzed with an equivalent circuit simulation. The conductance of the charge transfer was found to increase with current density up to a point where a raising limitation process of the complex methanol oxidation dominates, which is not a bottleneck at low current density. Further, an increase of the double layer capacitance with current density was observed. The diffusion resistance was calculated as an effective diffusion coefficient in the order of 10-10 m2 s-1; implying that the diffusion limitation is not the bulk diffusion in the backing layer. Finally, the degree of poisoning of the catalysts by carbon monoxide was measured as a pseudo inductive arc and decreases with increasing current.

  12. Qualification testing of secondary sterilizable silver-zinc cells for use in the Jupiter atmospheric entry probe

    NASA Technical Reports Server (NTRS)

    Manzo, M. A.

    1981-01-01

    A series of qualification tests were run on the secondary, sterilizable silver oxide - zinc cell developed at the NASA Lewis Research Center to determine if the cell was capable of providing mission power requirements for the Jupiter atmospheric entry probe. The cells were tested for their ability to survive radiation at the levels predicted for the Jovian atmosphere with no loss of performance. Cell performance was evaluated under various temperature and loading conditions, and the cells were tested under various environmental conditions related to launch and to deceleration into the Jovian atmosphere. The cell performed acceptably except under the required loading at low temperatures. The cell was redesigned to improve low-temperature performance and energy density. The modified cells improved performance at all temperatures. Results of testing cells of both the original and modified designs are discussed.

  13. Heterologous expression of vacuolar H(+)-PPase enhances the electrochemical gradient across the vacuolar membrane and improves tobacco cell salt tolerance.

    PubMed

    Duan, Xiao-Guang; Yang, Ai-Fang; Gao, Feng; Zhang, Shang-Li; Zhang, Ju-Ren

    2007-01-01

    The vacuolar H(+)-translocating inorganic pyrophosphatase (H(+)-PPase) uses pyrophosphate as substrate to generate the proton electrochemical gradient across the vacuolar membrane to acidify vacuoles in plant cells. The heterologous expression of H(+)-PPase genes (TsVP from Thellungiella halophila and AVP1 from Arabidopsis thaliana) improved the salt tolerance of tobacco plants. Under salt stress, the transgenic seedlings showed much better growth and greater fresh weight than wild-type plants, and their protoplasts had a normal appearance and greater vigor. The cytoplasmic and vacuolar pH in transgenic and wild-type cells were measured with a pH-sensitive fluorescence indicator. The results showed that heterologous expression of H(+)-PPase produced an enhanced proton electrochemical gradient across the vacuolar membrane, which accelerated the sequestration of sodium ions into the vacuole. More Na(+) accumulated in the vacuoles of transgenic cells under salt (NaCl) stress, revealed by staining with the fluorescent indicator Sodium Green. It was concluded that the tonoplast-resident H(+)-PPase plays important roles in the maintenance of the proton gradient across the vacuolar membrane and the compartmentation of Na(+) within vacuoles, and heterologous expression of this protein enhanced the electrochemical gradient across the vacuolar membrane, thereby improving the salt tolerance of tobacco cells. PMID:18094929

  14. Vanadium Oxide Electrochemical Capacitors: An Investigation into Aqueous Capacitive Degradation, Alternate Electrolyte-Solvent Systems, Whole Cell Performance and Graphene Oxide Composite Electrodes

    NASA Astrophysics Data System (ADS)

    Engstrom, Allison Michelle

    Vanadium oxide has emerged as a potential electrochemical capacitor material due to its attractive pseudocapacitive performance; however, it is known to suffer from capacitive degradation upon sustained cycling. In this work, the electrochemical cycling behavior of anodically electrodeposited vanadium oxide films with various surface treatments in aqueous solutions is investigated at different pH. Quantitative compositional analysis and morphological studies provide additional insight into the mechanism responsible for capacitive degradation. Furthermore, the capacitance and impedance behavior of vanadium oxide electrochemical capacitor electrodes is compared for both aqueous and nonaqueous electrolyte-solvent systems. Alkali metal chloride and bromide electrolytes were studied in aqueous systems, and nonaqueous systems containing alkali metal bromides were studied in polar aprotic propylene carbonate (PC) or dimethyl sulfoxide (DMSO) solvents. The preferred aqueous and nonaqueous systems identified in the half-cell studies were utilized in symmetric vanadium oxide whole-cells. An aqueous system utilizing a 3.0 M NaCl electrolyte at pH 3.0 exhibited an excellent 96% capacitance retention over 3000 cycles at 10 mV s-1. An equivalent system tested at 500 mV s-1 displayed an increase in capacitance over the first several thousands of cycles, and eventually stabilized over 50,000 cycles. Electrodes cycled in nonaqueous 1.0 M LiBr in PC exhibited mostly non-capacitive charge-storage, and electrodes cycled in LiBr-DMSO exhibited a gradual capacitive decay over 10,000 cycles at 500 mV s-1. Morphological and compositional analyses, as well as electrochemical impedance modeling, provide additional insight into the cause of the cycing behavior. Lastly, reduced graphene oxide and vanadium oxide nanowire composites have been successfully synthesized using electrophoretic deposition for electrochemical capacitor electrodes. The composite material was found to perform with a higher capacitance than electrodes containing only vanadium oxide nanowires by a factor of 4.0 at 10 mV s-1 and 7.5 at 500 mV s-1. The thermally reduced composite material was examined in both symmetric and asymmetric whole cell electrochemical capacitor devices, and although the asymmetric cell achieved both higher energy and power density, the symmetric cell retained a higher capacitance over 50,000 cycles at 200 mV s-1.

  15. Steady-state electrochemical determination of lipidic nanotube diameter utilizing an artificial cell model

    PubMed Central

    Adams, Kelly L.; Engelbrektsson, Johan; Voinova, Marina; Zhang, Bo; Eves, Daniel J.; Karlsson, Roger; Heien, Michael L.; Cans, Ann-Sofie; Ewing, Andrew G.

    2010-01-01

    By exploiting the capabilities of steady-state electrochemical measurements, we have measured the inner diameter of a lipid nanotube using Fick's first law of diffusion in conjunction with an imposed linear concentration gradient of electroactive molecules over the length of the nanotube. Fick's law has been used in this way to provide a direct relationship between the nanotube diameter and the measurable experimental parameters ?i (change in current) and nanotube length. Catechol was used to determine the ?i attributed to its flux out of the nanotube. Comparing the nanotube diameter as a function of nanotube length revealed that membrane elastic energy was playing an important role in determining the size of the nanotube and was different when the tube was connected to either end of two vesicles or to a vesicle on one end and a pipette tip on the other. We assume that repulsive interaction between neck regions can be used to explain the trends observed. This theoretical approach based on elastic energy considerations provides a qualitative description consistent with experimental data. PMID:20039639

  16. Rapid, Single-Cell Electrochemical Detection of Mycobacterium tuberculosis Using Colloidal Gold Nanoparticles.

    PubMed

    Ng, Benjamin Y C; Xiao, Wei; West, Nicholas P; Wee, Eugene J H; Wang, Yuling; Trau, Matt

    2015-10-20

    Tuberculosis (TB) remains a global health threat, with over a third of the world population suffering from the disease, and 1.5 million deaths due to the disease in 2013 alone. Despite significant advances in TB detection strategies in recent years, a bigger push toward detecting TB in the shortest and easiest way possible at the point-of-care (POC) is still in demand. To this end, we have designed a simple yet rapid and sensitive bioassay that detects Mtb DNA electrochemically using colloidal gold nanoparticles. This assay couples rapid isothermal amplification of target DNA that is specific to Mtb with gold nanoparticle electrochemistry on disposable screen printed carbon electrodes. The assay is capable of detecting a positive differential pulse voltammetry (DPV) response from as low as 1 CFU of Mtb bacilli DNA input material, having shown its exquisite sensitivity over a conventional gel based readout. The translation of our assay onto a portable potentiostat was also demonstrated, with promising results. We believe that our assay has significant potential for translation into broader bioassay applications or development as a POC diagnostic tool. PMID:26382883

  17. Development of IL-22–producing NK lineage cells from umbilical cord blood hematopoietic stem cells in the absence of secondary lymphoid tissue

    PubMed Central

    Tang, Qin; Ahn, Yong-Oon; Southern, Peter; Blazar, Bruce R.; Miller, Jeffery S.

    2011-01-01

    Human secondary lymphoid tissues (SLTs) contain interleukin-22 (IL-22)–producing cells with an immature NK phenotype. Given their location, these cells are difficult to study. We have generated large numbers of NK22 cells from hematopoietic stem cells. HSC-derived NK22 cells show a CD56+CD117highCD94? phenotype, consistent with stage III NK progenitors. Like freshly isolated SLT stage III cells, HSC-derived NK22 cells express NKp44, CD161, CCR6, IL1 receptor, AHR, and ROR-??. IL-1? and IL-23 stimulation results in significant IL-22 but not interferon-? production. Supernatant from these cells increases CD54 expression on mesenchymal stem cells. Thus, IL-22–producing NK cells can be generated in the absence of SLT. HSC-derived NK22 cells will be valuable in understanding this rare NK subset and create the opportunity for human translational clinical trials. PMID:21310921

  18. A Study Of Electrochemical Performance And Degradation Of Solid Oxide Fuel Cell Cathodes Based On Three Dimensional Tomography

    NASA Astrophysics Data System (ADS)

    Yakal-Kremski, Kyle

    Several different solid oxide fuel cell (SOFC) cathodes, produced using varied processing conditions and subsequently subjected to different thermal ageing and current loading conditions, were assessed. The resultant electrode performance was evaluated by electrochemical impedance spectroscopy and the results interpreted through extensive use of focused ion beam---scanning electron microscope (FIB-SEM) 3D tomography. Two, three, and four phase segmentation of tomographic data sets was achieved by use of several segmentation techniques, including thresholding, EM/MPM, and a method developed for this work, called self-similar region isolation segmentation. (La0.8Sr0.2)0.98MnO3-delta-(Y 2O3)0.08(ZrO2)0.92 (LSM-YSZ) symmetrical cells were manufactured and subjected to various firing temperatures, intermediate temperature anneals, and run in a novel mode of switching current to simulate operation in a reversible solid oxide cell. FIB-SEM was used to determine the reason(s) behind the observed minimum in RP at a firing temperature of 1175°C. Annealing of LSM-YSZ cells was used to simulate long times at operating temperature, with FIB-SEM used as a tool to observe changes that occur at high temperature, as compared to temperatures closer to those used in normal fuel cell operation. FIB-SEM data sets were used to map locations of metallic Ag impurity deposits in LSM-YSZ cells with time at current. La0.6Sr0.4Co0.8Fe0.2O 3-lambda (LSCF) electrodes in symmetrical cells were life tested at SOFC operating temperature both with and without constant current. While the LSCF electrodes annealed without current showed a substantial increase in polarization resistance with time, those tested with current were essentially stable. FIB-SEM 3D image analysis before and after the life tests showed that there were no significant microstructural changes. X-ray photoelectron spectroscopy (XPS) analysis was carried out to observe if changes in LSCF surface composition, such as Sr segregation, were responsible for the performance degradation. Although the XPS results did not show significant differences in surface composition between the life tested electrodes, the analysis may hint at changes in surface structure with thermal annealing. FIB-SEM tomography was also used as a tool to facilitate the determination of Nd2NiO4-+gamma cathode transport kinetic parameters---oxygen diffusion coefficient and oxygen chemical surface exchange coefficient, These parameters were calculated using the Adler-Lane-Steele model for porous mixed-conducting electrodes, with measured 3D microstructural parameters and electrochemical impedance spectroscopy data as inputs. Microstructural limits to the model were determined by comparing results from electrodes with varying particle sizes.

  19. Evaluation Program for Secondary Spacecraft Cells: Synchronous Orbit Testing of Sealed Nickel Cadmium Cells

    NASA Technical Reports Server (NTRS)

    Harkness, J. D.

    1977-01-01

    Performance data concerning sealed nickel-cadmium cells operating under a synchronous orbit regime are presented. A space satellite maintaining a position over a fixed point on earth as the earth rotates on its axis and revolves about the sun was simulated. Results include: (1) exposure to synchronous orbit testing at a temperature of 40 C yields less than 6 years of life; (2) performance at -20 C presents a low capacity problem; (3) the capacity check, performed at the middle of each show period, provides a temporary red reconditioning effect on the cells in that the end-of-discharge voltages are higher, for approximately 7 to 10 days, following the capacity check than they were 7 to 10 days prior to the capacity check; (4) all the test packs at -20 C and 40 C have either failed or were discontinued because of low capacity; and (5) test packs at temperatures of 0 C and 10 C have delivered the best capacity during life and packs tested at 20 C showed better life capability than packs tested at -20 C and 40 C.

  20. Electrochemical state and internal variables estimation using a reduced-order physics-based model of a lithium-ion cell and an extended Kalman filter

    NASA Astrophysics Data System (ADS)

    Stetzel, Kirk D.; Aldrich, Lukas L.; Trimboli, M. Scott; Plett, Gregory L.

    2015-03-01

    This paper addresses the problem of estimating the present value of electrochemical internal variables in a lithium-ion cell in real time, using readily available measurements of cell voltage, current, and temperature. The variables that can be estimated include any desired set of reaction flux and solid and electrolyte potentials and concentrations at any set of one-dimensional spatial locations, in addition to more standard quantities such as state of charge. The method uses an extended Kalman filter along with a one-dimensional physics-based reduced-order model of cell dynamics. Simulations show excellent and robust predictions having dependable error bounds for most internal variables.

  1. Surface science and electrochemical studies of metal-modified carbides for fuel cells and hydrogen production

    NASA Astrophysics Data System (ADS)

    Kelly, Thomas Glenn

    Carbides of the early transition metals have emerged as low-cost catalysts that are active for a wide range of reactions. The surface chemistry of carbides can be altered by modifying the surface with small amounts of admetals. These metal-modified carbides can be effective replacements for Pt-based bimetallic systems, which suffer from the drawbacks of high cost and low thermal stability. In this dissertation, metal-modified carbides were studied for reactions with applications to renewable energy technologies. It is demonstrated that metal-modified carbides possess high activity for alcohol reforming and electrochemical hydrogen production. First, the surface chemistry of carbides towards alcohol decomposition is studied using density functional theory (DFT) and surface science experiments. The Vienna Ab initio Simulation Package (VASP) was used to calculate the binding energies of alcohols and decomposition intermediates on metal-modified carbides. The calculated binding energies were then correlated to reforming activity determined experimentally using temperature programmed desorption (TPD). In the case of methanol decomposition, it was found that tungsten monocarbide (WC) selectively cleaved the C-O bond to produce methane. Upon modifying the surface with a single layer of metal such as Ni, Pt, or Rh, the selectivity shifted towards scission of the C-H bonds while leaving the C-O bond intact, producing carbon monoxide (CO) and H2. High resolution energy loss spectroscopy (HREELS) was used to examine the bond breaking sequence as a function of temperature. From HREELS, it was shown that the surfaces followed an activity trend of Rh > Ni > Pt. The Au-modified WC surface possessed too low of a methanol binding energy, and molecular desorption of methanol was the most favorable pathway on this surface. Next, the ability of Rh-modified WC to break the C-C bond of C2 and C3 alcohols was demonstrated. HREELS showed that ethanol decomposed through an acetaldehyde intermediate on Rh/WC, and that the C-C bond was broken by 200 K. Finally, the suitability of metal-modified molybdenum carbide (Mo2C) as an ethanol decomposition catalyst was studied. A new reaction pathway of partial dehydrogenation to an acetaldehyde product was achieved by using Cu as an admetal. The second section of this dissertation was the study of metal-modified carbides for electrochemical hydrogen evolution. Previously, DFT calculations had predicted a similar hydrogen binding energy (HBE) between Pd-modified carbides and bulk Pd. Linear sweep voltammograms (LSV) demonstrated that Pd-modified WC and Mo2C possessed hydrogen evolution activity orders of magnitude greater than the bare carbides. The long-term stability of these surfaces under operating conditions was also examined. A two-hour chronopotentiometry experiment was performed, after which x-ray photoelectron spectroscopy (XPS) found that negligible loss of the Pd overlayer occurred. As an extension of this work, a DFT study was performed for several admetal/Mo2C combinations. It was shown that the HBE of these surfaces mostly correlated with the pure metal HBE. Some of these combinations were tested experimentally, but were unstable in the acidic electrolyte.

  2. Printed-Compliant Electrochemical Systems

    NASA Astrophysics Data System (ADS)

    Gaikwad, Abhinav Machhindra

    Compliant electronic devices such as health monitoring tags, wearable electronics, fabricated using add-on printing techniques or by patterning traditional silicon based electronics in ultrathin format, enable them to flex, stretch and twist without any noticeable change in performance. These devices require a power source---a primary or secondary battery---to power the electronics. Traditional forms of batteries are bulky and negate the advantages of this new class of devices. Herein, I investigate various printing techniques and architectures that enable compliant batteries and study the performance of such batteries under mechanical deformations. Firstly, this dissertation investigates electrochemical-mechanical performance of a dispenser printed micro-battery using a microfluidic cell. Nanoparticulate silver ink was printed and cured to form silver electrodes, which was charged in-situ to form a silver-zinc battery. The electrochemical performance of the silver-zinc micro-battery was similar to macro-sized batteries. The shear stress generated by flow of electrolyte over the electrode was used to emulate the shear stress generated during flexing and was used as a tool to study the shear strength of the silver electrode at different state of charge. The dissertation then investigates supported architecture as a reinforcement to maintain the performance of the battery under strain. We demonstrate a highly flexible Zn-MnO2 alkalinebattery by embedding the electrochemically active particles in a mesh support. The mesh support absorbs the stresses generated during flexing. A Similar principle was used to make a stretchable battery. The backbone of the stretchable electrode was a stretchable fabric with silver-coated fibers weaved through a rubber network, which served as the current collector. The fabric was coated with Zn and MnO2 to form a stretchable electrode. Due to the weave architecture the electrode could stretch by 100% without any loss is contact between the particles and the silver fabric. A flexible battery based on an embedded membrane with paper-like characteristics was fabricated to investigate, in detail the modes of failure in a flexible battery during mechanical strains. The dissertation then investigates electrochemical properties of an MnO2 electrode. The effects of mass transfer, electrolyte concentration and presence of Zn on the discharge characteristics of the MnO2 electrode were studied.

  3. High loading MnO2 nanowires on graphene paper: facile electrochemical synthesis and use as flexible electrode for tracking hydrogen peroxide secretion in live cells.

    PubMed

    Dong, Shuang; Xi, Jiangbo; Wu, Yanan; Liu, Hongwei; Fu, Chaoyang; Liu, Hongfang; Xiao, Fei

    2015-01-01

    Recent progress in flexible and lightweight electrochemical sensor systems requires the development of paper-like electrode materials. Here, we report a facile and green synthesis of a new type of MnO2 nanowires-graphene nanohybrid paper by one-step electrochemical method. This strategy demonstrates a collection of unique features including the effective electrochemical reduction of graphene oxide (GO) paper and the high loading of MnO2 nanowires on electrochemical reduced GO (ERGO) paper. When used as flexible electrode for nonenzymatic detection of hydrogen peroxide (H2O2), MnO2-ERGO paper exhibits high electrocatalytic activity toward the redox of H2O2 as well as excellent stability, selectivity and reproducibility. The amperometric responses are linearly proportional to H2O2 concentration in the range 0.1-45.4 mM, with a detection limit of 10 ?M (S/N=3) and detection sensitivity of 59.0 ?A cm(-2) mM(-1). These outstanding sensing performances enable the practical application of MnO2-ERGO paper electrode for the real-time tracking H2O2 secretion by live cells macrophages. Therefore, the proposed graphene-based nanohybrid paper electrode with intrinsic flexibility, tailorable shapes and adjustable properties can contribute to the full realization of high-performance flexible electrode material used in point-of-care testing devices and portable instruments for in-vivo clinical diagnostics and on-site environmental monitoring. PMID:25467459

  4. Carbon foam anode modified by urea and its higher electrochemical performance in marine benthic microbial fuel cell

    NASA Astrophysics Data System (ADS)

    Fu, Yubin; Lu, Zhikai; Zai, Xuerong; Wang, Jian

    2015-08-01

    Electrode materials have an important effect on the property of microbial fuel cell (MFC). Carbon foam is utilized as an anode and further modified by urea to improve its performance in marine benthic microbial fuel cell (BMFC) with higher voltage and output power. The electrochemical properties of plain carbon foam (PC) and urea-modified carbon foam (UC) are measured respectively. Results show that the UC obtains better wettability after its modification and higher anti-polarization ability than the PC. A novel phenomenon has been found that the electrical potential of the modified UC anode is nearly 100 mV lower than that of the PC, reaching -570 ±10 mV ( vs. SCE), and that it also has a much higher electron transfer kinetic activity, reaching 9399.4 mW m-2, which is 566.2-fold higher than that from plain graphite anode (PG). The fuel cell containing the UC anode has the maximum power density (256.0 mW m-2) among the three different BMFCs. Urea would enhance the bacteria biofilm formation with a more diverse microbial community and maintain more electrons, leading to a lower anodic redox potential and higher power output. The paper primarily analyzes why the electrical potential of the modified anode becomes much lower than that of others after urea modification. These results can be utilized to construct a novel BMFC with higher output power and to design the conditioner of voltage booster with a higher conversion ratio. Finally, the carbon foam with a bigger pore size would be a potential anodic material in conventional MFC.

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

    SciTech Connect

    2010-09-09

    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.

  6. Electrochemical formation of a Pt/Zn alloy and its use as a catalyst for oxygen reduction reaction in fuel cells.

    PubMed

    Sode, Aya; Li, Winton; Yang, Yanguo; Wong, Phillip C; Gyenge, Elod; Mitchell, Keith A R; Bizzotto, Dan

    2006-05-01

    The characterization of an electrochemically created Pt/Zn alloy by Auger electron spectroscopy is presented indicating the formation of the alloy, the oxidation of the alloy, and the room temperature diffusion of the Zn into the Pt regions. The Pt/Zn alloy is stable up to 1.2 V/RHE and can only be removed with the oxidation of the base Pt metal either electrochemically or in aqua regia. The Pt/Zn alloy was tested for its effectiveness toward oxygen reduction. Kinetics of the oxygen reduction reaction (ORR) were measured using a rotating disk electrode (RDE), and a 30 mV anodic shift in the potential of ORR was found when comparing the Pt/Zn alloy to Pt. The Tafel slope was slightly smaller than that measured for the pure Pt electrode. A simple procedure for electrochemically modifying a Pt-containing gas diffusion electrode (GDE) with Zn was developed. The Zn-treated GDE was pressed with an untreated GDE anode, and the created membrane electrode assembly was tested. Fuel cell testing under two operating conditions (similar anode and cathode inlet pressures, and a larger cathode inlet pressure) indicated that the 30 mV shift observed on the RDE was also evident in the fuel cell tests. The high stability of the Pt/Zn alloy in acidic environments has a potential benefit for fuel cell applications. PMID:16640427

  7. Secondary cell wall development in cotton fibers as examined with attenuated total reflection Fourier transform infrared spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cotton fibers harvested at 18, 20, 24, 28, 32, 36 and 40 days after flowering were examined using attenuated total reflection Fourier transform-infrared (ATR FT-IR) spectroscopy. The selected harvesting points coincide with secondary cell wall (SCW) development in the fibers. Progressive but moderat...

  8. Microstructures and electrochemical properties of a SiO1.39-C composite for a lithium-ion secondary battery

    NASA Astrophysics Data System (ADS)

    Cheon, Jung Hoon; Jang, Bo Yun; Kim, Jun Soo; Lee, Jin Seok; Cho, Churl Hee

    2013-04-01

    SiO1.39 nanoparticles synthesized by using an evaporation and condensation process were composited with phenol resin and conducting carbon (C), and their microstructures and electrochemical properties were investigated. A dense, micro-sized SiO1.39-C composite was synthesized to prevent capacity fading of the SiO x nanoparticles. To densify and coarsen this composite, we carried out pelletizing, annealing and crushing of the sample. The electrical conductivity was also improved by the composition without any structural change. Crushed particles were used as an anode material for a Li-ion battery, and its cyclic performance was evaluated. By composition, the coulombic efficiency was observed to increase from 93.6 to 97.5% at the 5 th cycle, and it continued increasing with each additional cycle. For the composite annealed at 1,000 °C in a 4-vol.% H2/Ar atmosphere, the specific capacity and the coulombic efficiency at the 20 th cycle were measured as 426 mAhg-1 and 99.7%, respectively.

  9. Arabidopsis NMD3 is required for nuclear export of 60S ribosomal subunits and affects secondary cell wall thickening.

    PubMed

    Chen, Mei-Qin; Zhang, Ai-Hong; Zhang, Quan; Zhang, Bao-Cai; Nan, Jie; Li, Xia; Liu, Na; Qu, Hong; Lu, Cong-Ming; Sudmorgen; Zhou, Yi-Hua; Xu, Zhi-Hong; Bai, Shu-Nong

    2012-01-01

    NMD3 is required for nuclear export of the 60S ribosomal subunit in yeast and vertebrate cells, but no corresponding function of NMD3 has been reported in plants. Here we report that Arabidopsis thaliana NMD3 (AtNMD3) showed a similar function in the nuclear export of the 60S ribosomal subunit. Interference with AtNMD3 function by overexpressing a truncated dominant negative form of the protein lacking the nuclear export signal sequence caused retainment of the 60S ribosomal subunits in the nuclei. More interestingly, the transgenic Arabidopsis with dominant negative interference of AtNMD3 function showed a striking failure of secondary cell wall thickening, consistent with the altered expression of related genes and composition of cell wall components. Observation of a significant decrease of rough endoplasmic reticulum (RER) in the differentiating interfascicular fiber cells of the transgenic plant stems suggested a link between the defective nuclear export of 60S ribosomal subunits and the abnormal formation of the secondary cell wall. These findings not only clarified the evolutionary conservation of NMD3 functions in the nuclear export of 60S ribosomal subunits in yeast, animals and plants, but also revealed a new facet of the regulatory mechanism underlying secondary cell wall thickening in Arabidopsis. This new facet is that the nuclear export of 60S ribosomal subunits and the formation of RER may play regulatory roles in coordinating protein synthesis in cytoplasm and transcription in nuclei. PMID:22558264

  10. Photoactive area modification in bulk heterojunction organic solar cells using optimization of electrochemically synthesized ZnO nanorods

    NASA Astrophysics Data System (ADS)

    Mehdi, Ahmadi; Sajjad Rashidi, Dafeh

    2015-11-01

    In this work, ZnO nanorod arrays grown by an electrochemical deposition method are investigated. The crucial parameters of length, diameter, and density of the nanorods are optimized over the synthesize process and nanorods growth time. Crystalline structure, morphologies, and optical properties of ZnO nanorod arrays are studied by different techniques such as x-ray diffraction, scanning electron microscope, atomic force microscope, and UV–visible transmission spectra. The ZnO nanorod arrays are employed in an inverted bulk heterojunction organic solar cell of Poly (3-hexylthiophene):[6-6] Phenyl-(6) butyric acid methyl ester to introduce more surface contact between the electron transporter layer and the active layer. Our results show that the deposition time is a very important factor to achieve the aligned and uniform ZnO nanorods with suitable surface density which is required for effective infiltration of active area into the ZnO nanorod spacing and make a maximum interfacial surface contact for electron collection, as overgrowing causes nanorods to be too dense and thick and results in high resistance and lower visible light transmittance. By optimizing the thickness of the active layer on top of ZnO nanorods, an improved efficiency of 3.17% with a high FF beyond 60% was achieved.

  11. Efficient solid-state host-guest light-emitting electrochemical cells based on cationic transition metal complexes

    NASA Astrophysics Data System (ADS)

    Su, Hai-Ching; Wu, Chung-Chih; Fang, Fu-Chuan; Wong, Ken-Tsung

    2006-12-01

    The authors demonstrate highly efficient solid-state light-emitting electrochemical cells (LECs) consisting of green-emitting [Ir(dFppy)2(SB)]+(PF6-) as the host and orange-emitting [Ir(ppy)2(SB)]+(PF6-) as the guest [where dFppy is 2-(2,4-difluorophenyl)pyridine, SB is 4,5-diaza-9,9'-spirobifluorene, and ppy is 2-phenylpyridine]. Photophysical studies show that with the optimized host-guest compositions, the emission is mainly from the guest and photoluminescence quantum yields are largely enhanced over those of pure host and guest films due to suppressed intermolecular interactions. Correspondingly, LECs based on such host-guest cationic complex systems show substantially enhanced quantum efficiencies (power efficiencies) of up to 10.4% (36.8lm/W), representing a 1.5 times enhancement compared to those of pure host and guest devices. Such results indicate that the host-guest system is essential and useful for achieving highly efficient solid-state LECs.

  12. Electrochemical detection of intracellular and cell membrane redox systems in Saccharomyces cerevisiae

    NASA Astrophysics Data System (ADS)

    Rawson, Frankie J.; Downard, Alison J.; Baronian, Keith H.

    2014-06-01

    Redox mediators can interact with eukaryote cells at a number of different cell locations. While cell membrane redox centres are easily accessible, the redox centres of catabolism are situated within the cytoplasm and mitochondria and can be difficult to access. We have systematically investigated the interaction of thirteen commonly used lipophilic and hydrophilic mediators with the yeast Saccharomyces cerevisiae. A double mediator system is used in which ferricyanide is the final electron acceptor (the reporter mediator). After incubation of cells with mediators, steady state voltammetry of the ferri/ferrocyanide redox couple allows quantitation of the amount of mediator reduced by the cells. The plateau current at 425 mV vs Ag/AgCl gives the analytical signal. The results show that five of the mediators interact with at least three different trans Plasma Membrane Electron Transport systems (tPMETs), and that four mediators cross the plasma membrane to interact with cytoplasmic and mitochondrial redox molecules. Four of the mediators inhibit electron transfer from S. cerevisiae. Catabolic inhibitors were used to locate the cellular source of electrons for three of the mediators.

  13. Electrochemical detection of intracellular and cell membrane redox systems in Saccharomyces cerevisiae

    PubMed Central

    Rawson, Frankie J.; Downard, Alison J.; Baronian, Keith H.

    2014-01-01

    Redox mediators can interact with eukaryote cells at a number of different cell locations. While cell membrane redox centres are easily accessible, the redox centres of catabolism are situated within the cytoplasm and mitochondria and can be difficult to access. We have systematically investigated the interaction of thirteen commonly used lipophilic and hydrophilic mediators with the yeast Saccharomyces cerevisiae. A double mediator system is used in which ferricyanide is the final electron acceptor (the reporter mediator). After incubation of cells with mediators, steady state voltammetry of the ferri/ferrocyanide redox couple allows quantitation of the amount of mediator reduced by the cells. The plateau current at 425?mV vs Ag/AgCl gives the analytical signal. The results show that five of the mediators interact with at least three different trans Plasma Membrane Electron Transport systems (tPMETs), and that four mediators cross the plasma membrane to interact with cytoplasmic and mitochondrial redox molecules. Four of the mediators inhibit electron transfer from S. cerevisiae. Catabolic inhibitors were used to locate the cellular source of electrons for three of the mediators. PMID:24910017

  14. The electrochemical properties of lithium/sulfur cell using sulfur-carbon nanotubes composite.

    PubMed

    Kim, Dong-Ju; Park, Jin-Woo; Kim, Jong-Seon; Cho, Kweon-Koo; Kim, Ki-Won; Ahn, Jou-Hyeon; Jo, Min-Kyung; Choi, Hyun-Joo; Bae, Dong-Hyun; Ahn, Hyo-Jun

    2011-01-01

    Sulfur electrode was prepared using sulfur-CNT composite powder. The sulfur electrode showed homogenous mixture of sulfur and the CNTs with a network structure. We investigated on the discharge behavior and cycling property of lithium/sulfur cell using sulfur electrodes with CNTs as unique conducting agents. The discharge capacity of the Li/TEGDME/S cell was about 1227 mAh/g-sulfur for the first cycle and decreased to 155 mAh/g-sulfur after 14 cycles. PMID:21446481

  15. Integrated function of microbial fuel cell (MFC) as bio-electrochemical treatment system associated with bioelectricity generation under higher substrate load.

    PubMed

    Mohan, S Venkata; Raghavulu, S Veer; Peri, Dinakar; Sarma, P N

    2009-03-15

    Function of microbial fuel cell (MFC) as bio-electrochemical treatment system in concurrence with power generation was evaluated with composite chemical wastewater at high loading conditions (18.6 gCOD/l; 56.8 gTDS/l). Two dual chambered MFCs [non-catalyzed graphite electrodes; mediatorless anode] were studied separately with aerated and potassium ferricyanide catholytes under similar anodic operating conditions [mixed consortia; pH 6]. Marked improvement in power output was observed at applied higher substrate loading rate for extended period of time without any process inhibition. Catholyte nature showed significant influence on power generation [ferricyanide-651 mV; 18.22 mA; 6230 mW/kg COD(R) (500 Omega); 2321.69 mA/m(2) (100 Omega); 11.80 mW/m(3) and aerated-578 mV; 10.23mA; 2450 mW/kg COD(R) (400 Omega); 1220.68 mA/m(2) (100 Omega); 5.64 mW/m(3)] but not on wastewater treatment efficiency. Along with enhanced substrate degradation, relatively good removal of color (31%) and TDS (51%) was also observed during MFC operation, which might be attributed to the diverse bio-electrochemical processes triggered due to substrate metabolism and subsequent in situ bio-potential (voltage) generation. Apart from power generation, various unit operations pertaining to wastewater treatment viz., biological (anaerobic) process, electrochemical decomposition and electrochemical oxidation were found to occur symbiotically in the anode chamber. Among them anaerobic metabolism is considered to be a crucial and important rate limiting step. In view of inherent advantages, function of MFC as integrated bio-electrochemical treatment system in the direction of various wastewater treatment operations can be exploited. PMID:19058958

  16. Spherical carbon particles and carbon nanotubes prepared by autogenic reactions : evaluation as anodes in lithium electrochemical cells.

    SciTech Connect

    Pol, V. G.; Thackeray, M. M.

    2011-05-01

    Autogenic reactions, based on the decomposition of one or more precursors at elevated temperatures with self generated pressures can be used to prepare a wide range of materials with interesting structural, morphological and technological properties. Recent reports that spherical carbon particles and carbon nanotubes can be prepared by this technique from waste products, such as used plastic bags, have highlighted this environmentally-attractive approach to synthesize new or modified carbon-based materials. In this paper, we report the synthesis of spherical carbon particles and carbon nanotubes and their evaluation as negative electrodes (anodes) in lithium electrochemical cells. A steady reversible capacity of approximately 240 mAh/g for hundreds of cycles was achieved from both types of carbon, when cycled at a 1C rate between 1.5 V and 5 mV. A reversible capacity of 372 mAh/g, i.e., the theoretical value for graphite, was obtained from the carbon nanotube electrodes by raising the upper voltage limit to 3 V. To increase the graphitic order in the carbon spheres, the particles were heated to 2400 C in an inert atmosphere. This treatment reduced the first cycle irreversible capacity loss of Li/C half cells from 60 to 20%, the spherical carbon electrodes yielding a stable 252 mAh/g discharge capacity for numerous cycles. Structural and morphological information about the parent and cycled carbon electrodes, obtained by powder X-ray diffraction, Raman spectroscopy, high-resolution scanning electron microscopy, and electron dispersive analysis of X-rays is provided.

  17. Electrochemical Techniques

    SciTech Connect

    Chen, Gang; Lin, Yuehe

    2008-07-20

    Sensitive and selective detection techniques are of crucial importance for capillary electrophoresis (CE), microfluidic chips, and other microfluidic systems. Electrochemical detectors have attracted considerable interest for microfluidic systems with features that include high sensitivity, inherent miniaturization of both the detection and control instrumentation, low cost and power demands, and high compatibility with microfabrication technology. The commonly used electrochemical detectors can be classified into three general modes: conductimetry, potentiometry, and amperometry.

  18. Part I: In situ pulse electrochemical deposition of platinum nanoparticles for efficient catalyst utilization in fuel cells. Part II: Fabrication and characterization of polyelectrolyte-quantum dot hybrid structures using layer-by-layer self assembly

    NASA Astrophysics Data System (ADS)

    Ranasinghe, Asanga Devinda

    2007-12-01

    This thesis work is entirely committed towards extensive research on application of polyelectrolytes/polyelectrolyte membranes on the fields of materials science and electroanalytical chemistry. Part I highlights development of new electroanalytical techniques to deposit the electrocatalyst in proton exchange membrane (PEM) fuel cells. In this section of thesis work the major directions are to improve our basic knowledge and understanding factors limiting the efficient use of the electrocatalyst in fuel cells and develop and optimize a means for overcoming these limitations. Initially systematic studies will be performed to identify the limitations associated with the commercially available fuel cells followed by optimizing and utilizing the methods developed in this thesis work to manufacture functioning hydrogen PEM fuel cells using NafionRTM membrane via in situ electrodeposition of Pt. This research involves a detailed optimization of the pulse electrodeposition technique to deposit Pt using NafionRTM membrane as a template. Characterization of these experiments were done using techniques such as Cyclic Voltammetry (CV), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Secondary Ion Mass Spectrometry (SIMS), Energy Dispersion X-ray Spectrometry (EDX) and Inductively Couple Plasma (ICP). Finally construction of hydrogen fuel cells was done by in situ pulse electrochemical deposition through complete membrane electrode assemblies. Much of the attention of Part II is dedicated to construct and characterize polyelectrolyte and quantum dot hybrid multilayer structures. Much of the attention is focused towards investigation of the Forster energy transfer processes between the donor polyelectrolytes (poly-p-phenylelvinylene, PPV) and the acceptor ZnS/CdSe core/shell quantum dots with respect to its separation. The work shown in Chapter 7 explains the process of introduction of quantum dots to these multilayer thin films and analysis of these hybrid structures using Laser Scanning Confocal Microscopy (LSCM), excited state life time decay studies and UV-Vis absorption studies.

  19. CdS solar cells with electrochemically formed Cu2S Improvement of the current collect

    NASA Astrophysics Data System (ADS)

    Cowache, P.; Vedel, J.

    1985-12-01

    CdS-Cu2S solar cells are made by depositing Cu2S on CdS by cathodic reduction from a solution containing the Cu(2+) species. A gold grid is electroplated onto the Cu2S formed before CdS etching to ensure good contact and collecting conditions. The shape of the grid is delimited using a photoresist technique. To protect the grid against the subsequent acidic etching process and a frequently observed copper deposit during the formation of Cu2S, a passivation method involving anodic polymerisation is described. The formation of Cu2S, as well as the subsequent copper enrichment are therefore easily performed, leading to cells with efficiencies of up to 8 percent.

  20. Imaging the Solar Cell P-N Junction and Depletion Region Using Secondary Electron Contrast

    SciTech Connect

    Heath, J. T.; Jiang, C. S.; Al-Jassim, M. M.

    2011-01-01

    We report on secondary electron (SE) images of cross-sectioned multicrystalline Si and GaAs/GaInP solar cell devices, focusing on quantifying the relationship between the apparent n{sup +}-p contrast and characteristic electronic features of the device. These samples allow us to compare the SE signal from devices which have very different physical characteristics: differing materials, diffused junction versus abrupt junction, heterojunction versus homojunction. Despite these differences, we find that the SE image contrast for both types of sample, and as a function of reverse bias across the diode, closely agrees with PC1D simulations of the bulk electrostatic potential in the device, accurately yielding the depletion edge and width. A spatial derivative of the SE data shows a local maximum at the metallurgical junction. Such data are valuable, for example, in studying the conformity of a diffused junction to the textured surface topography. These data also extend our understanding of the origin of the SE contrast.