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1

Primary and secondary room temperature molten salt electrochemical cells  

NASA Astrophysics Data System (ADS)

Three novel primary cells which use room temperature molten salt electrolytes are examined and found to have high open circuit potentials in the 1.75-2.19 V range, by comparison with the Al/AlCl3-MEICl concentration cell; their cathodes were of FeCl3-MEICl, WCl6-MEICl, and Br2/reticulated vitreous carbon together with Pt. Also, secondary electrochemical cell candidates were examined which combined the reversible Al/AlCl3-MEICl electrode with reversible zinc and cadmium molten salt electrodes to yield open circuit potentials of about 0.7 and 1.0 V, respectively. Room temperature molten salts' half-cell reduction potentials are given.

Reynolds, G. F.; Dymek, C. J., Jr.

1985-07-01

2

Electrochemical cell  

DOEpatents

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.

Kaun, Thomas D. (New Lenox, IL)

1984-01-01

3

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

DOEpatents

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.

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

4

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

DOEpatents

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.

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

1982-07-07

5

Novel electrochemical system intended for 1.5 V nonmetallic hermetically sealed secondary cell  

SciTech Connect

A novel reversible system based on graphite and anthraquinone electrodes and intended for the development of a nonmetallic ecologically clean secondary cell is proposed. The principal problem associated with combining the two electrodes in a unified electrochemical system involves the search for an electrolyte which would be suitable for both electrodes. Optimum and limiting pH intervals as well as the influence exerted by the anion type on the electrode efficiency are considered. The use of combined electrolytes on the basis of HBF{sub 4} with tetrafluoroborate additives is recommended.

Barsukov, V.Z. [Institute of General and Inorganic Chemistry, Kiev (Ukraine); Barsukov, I.V.; Motronyuk, T.I. [Kiev Polytechnical Institute (Ukraine); Beck, F. [Univ. of Duisburg, Lotharstrabe (Germany)

1995-04-01

6

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

DOEpatents

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.

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

1981-05-22

7

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

DOEpatents

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.

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

1983-01-01

8

Electrochemical cell  

DOEpatents

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.

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

1994-02-01

9

Electrochemical cell  

DOEpatents

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.

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

10

Electrochemical cell  

DOEpatents

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. 6 figs.

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

1996-07-16

11

Electrochemical cell  

DOEpatents

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.

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

1994-01-01

12

Electrochemical cell  

DOEpatents

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.

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

1994-01-01

13

Electrochemical cell  

DOEpatents

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.

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

14

Electrochemical cell  

DOEpatents

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.

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

1996-07-02

15

Electrochemical cell  

DOEpatents

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.

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

1992-01-01

16

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

NASA Astrophysics Data System (ADS)

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.

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

2013-11-01

17

Electrochemical cell  

SciTech Connect

In accordance with the invention, a novel electrochemical cell and a method for making same is provided which is particularly suitable for use in a battery of the type employing one or more cells. One feature of the cell includes a sealed non-metallic pouch of thin flexible material which forms a cell adaptable to varying battery configurations as well as cell shapes. A second feature of the cell includes a novel feedthrough arrangement wherein a pair of electrically conductive members are located on respective sides of an interjacent throughhole formed in the housing material. The pair of electrically conductive members are coupled through the through-hole to form the feedthrough. An electrode of anode material is electrically coupled to the internally located member of one feedthrough pair. An electrode of cathode material is electrically coupled to the internally located member of the other feedthrough. The cell further includes electrically insulative porous material for separating the electrodes, as well as a volume of electrolyte electrochemically coupling the electrodes.

Epstein, J.; Marincic, N.

1985-04-02

18

Electrochemical cell  

DOEpatents

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.

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

1994-08-23

19

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

NASA Astrophysics Data System (ADS)

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.

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

2014-07-01

20

Electrochemical behavior of Li/LiV3O8 secondary cells  

NASA Astrophysics Data System (ADS)

Li/LiV3O8 secondary cells with Li-foil and Li-powder anodes were fabricated, and their electrical properties were compared. Using the powder anode, a cell with an initial discharge capacity of 260 mAh g-1 that could be operated for over 100 cycles was obtained. The porous Li-powder electrode was safely synthesized by pressing an emulsion droplet onto an SUS mesh. A threefold increase in the electrical conductivity of the LiV3O8 cathode was achieved by the addition of carbon using a vibration pot mill. Using the powder anode resulted in 80% capacity retention at the 100th cycle, while that using the foil electrode was 46%; the 1.0 Crate/ 0.1 C-rate capacity ratio also increased from 44% to 60%. A cell employing the LiV3O8-carbon composite cathode showed better electrical performance, a capacity retention of 90% after 50 cycles, and an increase in rate capacity ratio. The crystal structure and morphology of the LiV3O8-C composite were investigated by x-ray diffraction and scanning electron microscopy.

Bak, Hyo Rim; Lee, Jae Ha; Kim, Bok Ki; Yoon, Woo Young

2013-03-01

21

Electrochemical cell stack assembly  

DOEpatents

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.

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

2010-06-22

22

Electrolyte composition for electrochemical cell  

DOEpatents

A high-temperature, secondary electrochemical cell that employs FeS as the positive electrode reactant and lithium or lithium alloy as the negative electrode reactant includes an improved electrolyte composition. The electrolyte comprises about 60-70 mole percent LiCl and 30-40 percent mole percent KCl which includes LiCl in excess of the eutectic composition. The use of this electrolyte suppresses formation of the J phase and thereby improves the utilization of positive electrode active material during cell cycling.

Vissers, Donald R. (Naperville, IL); Tomczuk, Zygmunt (Orland Park, IL); Anderson, Karl E. (Westchester, IL); Roche, Michael F. (Downers Grove, IL)

1979-01-01

23

Separators for electrochemical cells  

DOEpatents

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.

Carlson, Steven Allen; Anakor, Ifenna Kingsley

2014-11-11

24

Electrochemical storage cell  

Microsoft Academic Search

Electrochemical storage cell with liquid sodium anode and liquid sulfur cathode disposed in a multiplicity of parallel-connected anode and cathode spaces in a part made of a ceramic, ion-conducting solid electrolyte material. The solid electrolyte part comprises profiled ceramic plates which have been sintered together and form mutually parallel channels with thin partitioning walls. The anode spaces formed by the

U. von Alpen; A. Krauth

1984-01-01

25

Nanocrystalline electrochemical solar cells  

SciTech Connect

Standard solar cells exploit the physics of semiconductors in which the energy of absorbed photons excites charge-carrier pairs which are subsequently separated by the influence of a solid state junction to provide a photovoltage. In the nanocrystalline electrochemical cell, the optical absorber is a dye monolayer which after photo-excitation injects electrons into a semiconductor substrate, with charge neutrality being restored by a chemical redox reaction. The circuit is completed through an electrolyte and a metallic counterlectrode. Present performance, industrial engagement in research and development and commercial prospects are presented.

McEvoy, A.J.; Graetzel, M. [Ecole Polytechnique Federale, Lausanne (Switzerland). Inst. de Chimie-Physique; Wittkopf, H.; Jestel, D.; Benemann, J. [Flachglas AG, Gelsenkirchen (Germany)

1994-12-31

26

Lithium-based polymer electrolyte electrochemical cell  

SciTech Connect

A primary or secondary electrochemical cell is described comprising: an anode containing lithium when in a charged state; a gelled electrolyte system comprising polyacrylonitrile (PAN), plasticizer including [gamma]-butyrolactone ([gamma]-BL) and a lithium electrolyte salt; and a cathode comprising a cathode active material selected from the group consisting of transition metal oxides and a lithium transition metal oxide intercalation compound.

Chua, D.L.; Hsiuping Lin.

1993-08-31

27

Porous electrodes and prototypes of secondary cells based on a novel electrochemical system graphite-HBF{sub 4}-anthraquinone  

SciTech Connect

Porous electrodes and experimental prototypes of rechargeable batteries based on a novel electrochemical system graphite-HBF{sub 4} + tetrafluoroborate additives-anthraquinone are developed. Intercalation of anions in the graphite electrode is studied in detail and the intercalation potential is determined (E{sub i} {approximately} 1.55 V vs. Ag-AgCl). Side reactions proceeding concurrently with primary current-generating processes at the electrodes are described. Feasibility of hermetically sealing a battery based on the new system due to anthrahydroquinone`s ability to reduce oxygen that evolves during charging is demonstrated.

Barsukov, V.Z. [Institute of General and Inorganic Chemistry, Kiev (Ukraine); Barsukov, I.V.; Motronyuk, T.I. [Kiev Polytechnical Institute (Ukraine); Beck, F. [Univ. of Duisburg (Germany)

1995-04-01

28

Electrochemical photovoltaic cells and electrodes  

DOEpatents

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.

Skotheim, Terje A. (East Patchogue, NY)

1984-01-01

29

Separator material for electrochemical cells  

DOEpatents

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.

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

1991-01-01

30

Separator material for electrochemical cells  

DOEpatents

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.

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

1991-03-26

31

Electrochemical sensor for monitoring electrochemical potentials of fuel cell components  

DOEpatents

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.

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

1993-01-01

32

Metal halogen electrochemical cell  

DOEpatents

It has now been discovered that reduction in the coulombic efficiency of metal halogen cells can be minimized if the microporous separator employed in such cells is selected from one which is preferably wet by the aqueous electrolyte and is not wet substantially by the cathodic halogen.

Bellows, Richard J. (Hampton, NJ); Kantner, Edward (E. Brunswick, NJ)

1988-08-23

33

Compacted carbon for electrochemical cells  

DOEpatents

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.

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

1997-01-01

34

Electrochemical cell having cylindrical electrode elements  

DOEpatents

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.

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

1982-01-01

35

Bussing Structure In An Electrochemical Cell  

DOEpatents

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.

Romero, Antonio L. (Parkton, MD)

2001-06-12

36

Chemically modified graphite for electrochemical cells  

DOEpatents

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.

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

1998-05-26

37

Chemically modified graphite for electrochemical cells  

DOEpatents

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.

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

1998-01-01

38

Boundary Layer Analysis of Membraneless Electrochemical Cells  

E-print Network

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 ...

Braff, William A.

39

Advances in ambient temperature secondary lithium cells  

NASA Technical Reports Server (NTRS)

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.

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

1989-01-01

40

Refractory lining for electrochemical cell  

DOEpatents

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.

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

1987-01-01

41

Nanodisperse transition metal electrodes (NTME) for electrochemical cells  

DOEpatents

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.

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

2000-01-01

42

Nanodisperse transition metal electrodes (NTME) for electrochemical cells  

SciTech Connect

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.

Striebel, Kathryn A.; Wen, Shi-Jie

1998-12-01

43

Textbook Error: Short Circuiting on Electrochemical Cell  

ERIC Educational Resources Information Center

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…

Bonicamp, Judith M.; Clark, Roy W.

2007-01-01

44

An electrochemical rebalance cell for Redox systems  

NASA Technical Reports Server (NTRS)

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.

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

1983-01-01

45

Gas recombination assembly for electrochemical cells  

DOEpatents

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.

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

1989-01-01

46

Method for vacuum pressing electrochemical cell components  

NASA Technical Reports Server (NTRS)

Assembling electrochemical cell components using a bonding agent comprising aligning components of the electrochemical cell, applying a bonding agent between the components to bond the components together, placing the components within a container that is essentially a pliable bag, and drawing a vacuum within the bag, wherein the bag conforms to the shape of the components from the pressure outside the bag, thereby holding the components securely in place. The vacuum is passively maintained until the adhesive has cured and the components are securely bonded. The bonding agent used to bond the components of the electrochemical cell may be distributed to the bonding surface from distribution channels in the components. To prevent contamination with bonding agent, some areas may be treated to produce regions of preferred adhesive distribution and protected regions. Treatments may include polishing, etching, coating and providing protective grooves between the bonding surfaces and the protected regions.

Andrews, Craig C. (Inventor); Murphy, Oliver J. (Inventor)

2004-01-01

47

Heteroatom incorporated coke for electrochemical cell electrode  

DOEpatents

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.

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

1997-06-17

48

Heteroatom incorporated coke for electrochemical cell electrode  

DOEpatents

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.

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

1997-01-01

49

Minimizing electrode contamination in an electrochemical cell  

DOEpatents

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.

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

2014-12-09

50

Alkaline electrochemical cells and method of making  

NASA Technical Reports Server (NTRS)

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.

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

1970-01-01

51

Glass fibre paper separator for electrochemical cells  

Microsoft Academic Search

A separator suitable for electrochemical cells of the lead-acid recombinant type comprises a sheet of entangled glass fibres. It has been found that significant improvements in performance can be obtained when 5 to 35% by weight of the fibres have a diameter of less than 1 ..mu..m. It has also been found surprisingly advantageous if the overall solubility of the

F. J. T

1984-01-01

52

Cathode for an electrochemical cell  

DOEpatents

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.

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

53

Electrolyte for an electrochemical cell  

DOEpatents

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.

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

1997-01-01

54

Electrolyte for an electrochemical cell  

DOEpatents

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.

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

1997-01-28

55

Electrochemical characteristics of lithium-ion cells  

SciTech Connect

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.

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

1998-01-01

56

Electrochemical cell with interlocking anode  

SciTech Connect

A reserve cell is described comprised of: a cylindrical housing having an interior wall; a cylindrical cathode current collector member abutting the interior wall; a cylindrical anode member with a spiral gap; a cylindrical porous separator interposed between the cathode current collector member and the anode member; a liquid cell component container centrally located within the housing; and a continuous anode support cylinder located between the anode member and the container. The anode cylinder has perforations into which the anode member is pressed, interlocking the anode member and the anode support cylinder.

Haskins, T.B.; Goebel, F.; Batson, D.C.; Zuffante, C.R.

1987-08-04

57

Electrochemical cell having internal short inhibitor  

SciTech Connect

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.

Hooke, J.W.

1984-04-24

58

Electrochemical Cell Design With A Hollow Gate  

DOEpatents

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.

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

59

Cycle life test. [of secondary spacecraft cells  

NASA Technical Reports Server (NTRS)

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.

Harkness, J. D.

1977-01-01

60

Solid oxide electrochemical cell fabrication process  

DOEpatents

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).

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

61

Partial-Vacuum-Gasketed Electrochemical Corrosion Cell  

NASA Technical Reports Server (NTRS)

An electrochemical cell for making corrosion measurements has been designed to prevent or reduce crevice corrosion, which is a common source of error in prior such cells. The present cell (see figure) includes an electrolyte reservoir with O-ring-edged opening at the bottom. In preparation for a test, the reservoir, while empty, is pressed down against a horizontal specimen surface to form an O-ring seal. A purge of air or other suitable gas is begun in the reservoir, and the pressure in the reservoir is regulated to maintain a partial vacuum. While maintaining the purge and partial vacuum, and without opening the interior of the reservoir to the atmosphere, the electrolyte is pumped into the reservoir. The reservoir is then slowly lifted a short distance off the specimen. The level of the partial vacuum is chosen such that the differential pressure is just sufficient to keep the electrolyte from flowing out of the reservoir through the small O-ring/specimen gap. Electrochemical measurements are then made. Because there is no gasket (and, hence, no crevice between the specimen and the gasket), crevice corrosion is unlikely to occur.

Bonifas, Andrew P.; Calle, Luz M.; Hintze, Paul E.

2006-01-01

62

Sensor apparatus using an electrochemical cell  

DOEpatents

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.

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

2002-01-01

63

Sensor apparatus using an electrochemical cell  

DOEpatents

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.

Thakur, Mrinal

2003-07-01

64

A Model Approach to the Electrochemical Cell: An Inquiry Activity  

ERIC Educational Resources Information Center

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…

Cullen, Deanna M.; Pentecost, Thomas C.

2011-01-01

65

Thermal regeneration of an electrochemical concentration cell  

DOEpatents

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.

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

1981-01-01

66

A high temperature molten salt thermal electrochemical cell  

NASA Astrophysics Data System (ADS)

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.

Plichta, Edward J.; Behl, Wishvender K.

1990-02-01

67

Sampling dynamics for pressurized electrochemical cells  

SciTech Connect

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.

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

2014-07-01

68

Fuel Cell/Electrochemical Cell Voltage Monitor  

NASA Technical Reports Server (NTRS)

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.

Vasquez, Arturo

2012-01-01

69

Composite electrode for use in electrochemical cells  

DOEpatents

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.

Vanderborgh, Nicholas E. (Los Alamos, NM); Huff, James R. (Los Alamos, NM); Leddy, Johna (Flushing, NY)

1989-01-01

70

Composite electrode for use in electrochemical cells  

DOEpatents

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.

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

1987-10-16

71

Electrochemical cell apparatus having an exterior fuel mixer nozzle  

Microsoft Academic Search

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

P. Reichner; V. B. Doshi

1992-01-01

72

Method for making an electrochemical cell  

DOEpatents

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.

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

1996-01-01

73

Evaluation program for secondary spacecraft cells  

NASA Technical Reports Server (NTRS)

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.

Harkness, J. D.

1978-01-01

74

Electrochemical cell to measure corrosion rates in noncondensing environments  

Microsoft Academic Search

We have constructedad used an electrochemical cell to estimate corrosion rates in a noncondensing environment, i.e., water-saturated air (100% relative humidity). In this initial effort, we compared the corrosion rates for a variety of metals and alloys in water-saturated air in the electrochemical cell with the corrosion rates of these materials in aerated and deaerated deionized water in an aqueous

J. J. Truhan; C. Chen; F. C. Kirk

1984-01-01

75

Thermal conductor for high-energy electrochemical cells  

DOEpatents

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.

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

76

Steel refining with an electrochemical cell  

DOEpatents

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.

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

1988-01-01

77

Electrochemical cell having improved pressure vent  

DOEpatents

The electrochemical cell of the instant invention includes a case having a gas outlet, one or more positive electrodes positioned within the case, one or more negative electrodes positioned within the case electrode separators positioned between the positive and negative electrodes, electrolyte positioned within the case, and a pressure vent for releasing internal pressure occurring in the case to the surrounding atmosphere. The pressure vent is affixed to the case covering the gas outlet, the pressure vent includes a vent housing having a hollow interior area in gaseous communication with the surrounding atmosphere and the interior of the case via the gas outlet, a pressure release piston positioned within the hollow interior area, the pressure release piston sized to surround the gas outlet and having a seal groove configured to encapsulate all but one surface of a seal mounted within the seal groove, leaving the non-encapsulated surface of the seal exposed, and a compression spring positioned to urge the pressure release piston to compress the seal in the seal groove and block the gas outlet in the case.

Dean, Kevin (Pontiac, MI); Holland, Arthur (Troy, MI); Fillmore, Donn (Waterford, MI)

1993-01-01

78

Steel refining with an electrochemical cell  

DOEpatents

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.

Blander, M.; Cook, G.M.

1988-05-17

79

Steel refining with an electrochemical cell  

DOEpatents

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.

Blander, M.; Cook, G.M.

1985-05-21

80

Method of doping interconnections for electrochemical cells  

DOEpatents

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.

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

1990-01-01

81

Hazards of Secondary Bromadiolone Intoxications Evaluated using High-performance Liquid Chromatography with Electrochemical Detection  

PubMed Central

This study reported on the possibility of intoxications of non-target wild animals associated with use of bromadiolone as the active component of rodenticides with anticoagulation effects. A laboratory test was done with earthworms were exposed to bromadiolone-containing granules under the conditions specified in the modified OECD 207 guideline. No mortality of earthworms was observed during the fourteen days long exposure. When the earthworms from the above test became a part of the diet of common voles in the following experiment, no mortality of consumers was observed too. However, electrochemical analysis revealed higher levels of bromadiolone in tissues from earthworms as well as common voles compared to control animals. There were determined comparable levels of bromadiolone in the liver tissue of common voles after primary (2.34±0.10 ?g/g) and secondary (2.20±0.53 ?g/g) intoxication. Therefore, the risk of secondary intoxication of small mammalian species feeding on bromadiolone-containing earthworms is the same as of primary intoxication through baited granules. Bromadiolone bio-accumulation in the food chain was monitored using the newly developed analytical procedure based on the use of a liquid chromatography coupled with electrochemical detector (HPLC-ED). The HPLC-ED method allowed to determine the levels of bromadiolone in biological samples and is therefore suitable for examining the environmental hazards of this substance.

Krizkova, Sona; Beklova, Miroslava; Pikula, Jiri; Adam, Vojtech; Horna, Ales; Kizek, René

2007-01-01

82

Secondary Symbiosis Between Paramecium and Chlorella Cells  

Microsoft Academic Search

Each symbiotic Chlorella species of Paramecium bursaria is enclosed in a perialgal vacuole (PV) membrane derived from the host digestive vacuole (DV) membrane. Algae-free paramecia and symbiotic algae are capable of growing independently and paramecia can be reinfected experimentally by mixing them. This phenomenon provides an excellent model for studying cell-to-cell interaction and the evolution of eukaryotic cells through secondary

Yuuki Kodama; Masahiro Fujishima

2010-01-01

83

Electrochemical cell utilizing molten alkali metal electrode-reactant  

SciTech Connect

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.

Virkar, A.V.; Miller, G.R.

1983-10-04

84

Electrochemical cell utilizing molten alkali metal electrode-reactant  

DOEpatents

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.

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

1983-11-04

85

The Variation of Electrochemical Cell Potentials with Temperature  

ERIC Educational Resources Information Center

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…

Peckham, Gavin D.; McNaught, Ian J.

2011-01-01

86

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

E-print Network

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

Lu, Chang

87

Electrochemical characteristics of acid electrolytes for fuel cells  

NASA Astrophysics Data System (ADS)

Five topics investigated by the Gas Research Institute (GRI) contractors at Case Western Reserve University (CWRU) during the past year included: (1) electrochemical evaluation of perfluorinated electrolyte, (2) the Nafion solid polymer electrolyte (SPE) fuel cell, (3) electrochemistry of single crystal Pt electrodes in acid solution, (4) catalytic effects of adatoms entrapped on electrode surfaces by bipolar or monopolar ion exchange membrane layers, (5) investigations of the Fleischmann-Pons phenomenon. The principal objective of the project is to evaluate new acid electrolytes. Electrochemical evaluation was made for two bisphosphonic acids as a replacement for phosphoric acid as a fuel cell electrolyte, and also a bis-sulfonyl carbon acid as an additive to concentrated phosphoric acid electrolyte for acid H2-O2 fuel cells. Electrochemical characteristics were found for these new perfluorinated acids.

Adzic, R.; Gervasio, D.; Kanamura, K.; Razaq, A.; Razaq, M.; Yeager, Ernest B.

1990-01-01

88

Assessing corrosion problems in photovoltaic cells via electrochemical stress testing  

NASA Technical Reports Server (NTRS)

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.

Shalaby, H.

1985-01-01

89

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

DOEpatents

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.

Gering, Kevin L

2013-08-27

90

Reconstitution of a secondary cell wall in a secondary cell wall-deficient Arabidopsis mutant.  

PubMed

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

Sakamoto, Shingo; Mitsuda, Nobutaka

2015-02-01

91

Continuous-feed electrochemical cell with nonpacking particulate electrode  

DOEpatents

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.

Cooper, J.F.

1995-07-18

92

Topographical and electrochemical nanoscale imaging of living cells using voltage-switching mode scanning electrochemical microscopy  

PubMed Central

We describe voltage-switching mode scanning electrochemical microscopy (VSM-SECM), in which a single SECM tip electrode was used to acquire high-quality topographical and electrochemical images of living cells simultaneously. This was achieved by switching the applied voltage so as to change the faradaic current from a hindered diffusion feedback signal (for distance control and topographical imaging) to the electrochemical flux measurement of interest. This imaging method is robust, and a single nanoscale SECM electrode, which is simple to produce, is used for both topography and activity measurements. In order to minimize the delay at voltage switching, we used pyrolytic carbon nanoelectrodes with 6.5–100 nm radii that rapidly reached a steady-state current, typically in less than 20 ms for the largest electrodes and faster for smaller electrodes. In addition, these carbon nanoelectrodes are suitable for convoluted cell topography imaging because the RG value (ratio of overall probe diameter to active electrode diameter) is typically in the range of 1.5–3.0. We first evaluated the resolution of constant-current mode topography imaging using carbon nanoelectrodes. Next, we performed VSM-SECM measurements to visualize membrane proteins on A431 cells and to detect neurotransmitters from a PC12 cells. We also combined VSM-SECM with surface confocal microscopy to allow simultaneous fluorescence and topographical imaging. VSM-SECM opens up new opportunities in nanoscale chemical mapping at interfaces, and should find wide application in the physical and biological sciences. PMID:22611191

Takahashi, Yasufumi; Shevchuk, Andrew I.; Novak, Pavel; Babakinejad, Babak; Macpherson, Julie; Unwin, Patrick R.; Shiku, Hitoshi; Gorelik, Julia; Klenerman, David; Korchev, Yuri E.; Matsue, Tomokazu

2012-01-01

93

Secondary fuel cell. [electrolytically-regenerative hydrogen fuel cells  

Microsoft Academic Search

This application discloses a secondary fuel cell having improved electrode zones. Each cell has two electrode zones each containing a pair of electrode structures. A first such electrode structure in each zone is more efficient in operation during discharge of the fuel cell. Electrical structure is provided so that the first electrode structures are utilized during charging of the fuel

R. J. Haas; D. C. Briggs

1978-01-01

94

Oxide modified air electrode surface for high temperature electrochemical cells  

DOEpatents

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.

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

1992-01-01

95

Electrode heat balances of electrochemical cells: Application to water electrolysis  

Microsoft Academic Search

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

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

1984-01-01

96

Mass spectrometric methods for monitoring redox processes in electrochemical cells  

PubMed Central

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

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

2015-01-01

97

Evaluation program for secondary spacecraft cells  

NASA Technical Reports Server (NTRS)

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.

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

1973-01-01

98

Method of low temperature operation of an electrochemical cell array  

DOEpatents

In the method of operating an electrochemical cell generator apparatus containing a generator chamber (20) containing an array of cells (12) having interior and exterior electrodes with solid electrolyte between the electrodes, where a hot gas (F) contacts the outside of the cells (12) and the generating chamber normally operates at over 850.degree. C., where N.sub.2 gas is fed to contact the interior electrode of the cells (12) in any case when the generating chamber (20) temperature drops for whatever reason to within the range of from 550.degree. C. to 800.degree. C., to eliminate cracking within the cells (12).

Singh, Prabhakar (Export, PA); Ruka, Roswell J. (Churchill Boro, PA); Bratton, Raymond J. (Delmont, PA)

1994-01-01

99

Corner heating in rectangular solid oxide electrochemical cell generators  

DOEpatents

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.

Reichner, Philip (Plum Boro, PA)

1989-01-01

100

Testing and analyses of electrochemical cells using frequency response  

NASA Technical Reports Server (NTRS)

The feasibility of electrochemical impedance spectroscopy as a method for analyzing battery state of health and state of charge was investigated. Porous silver, zinc, nickel, and cadmium electrodes as well as silver/zinc cells were studied. State of charge could be correlated with impedance data for all but the nickel electrodes. State of health was correlated with impedance data for two silver/zinc cells, one apparently good and the other dead. The experimental data were fit to equivalent circuit models.

Norton, O. A., Jr.; Thomas, D. L.

1992-01-01

101

The response of fibrinogen, platelets, endothelial and smooth muscle cells to an electrochemically modified SS316LS surface: Towards the enhanced biocompatibility of coronary stents  

Microsoft Academic Search

Modification of a biomedical-grade stainless steel 316LS surface by electrochemical cyclic potentiodynamic passivation (CPP) and the response of fibrinogen (Fg), platelets, endothelial cells (ECs) and smooth muscles cells (SMCs) to this surface was investigated. Polarization modulation infrared reflection absorption spectroscopy revealed a significant difference between the secondary structure of Fg adsorbed on the unmodified and CPP surface, the latter being

Arash Shahryari; Fereshteh Azari; Hojatollah Vali; Sasha Omanovic

2010-01-01

102

Synthesis and electrochemical behavior of nanosized LiNi{sub 1-x}Ca {sub x}O{sub 2} cathode materials for high voltage secondary lithium-ion cells  

SciTech Connect

A new class of LiNi{sub 1-x}Ca {sub x}O{sub 2} (x = 0.0, 0.1, 0.2, 0.3 and 0.5) layered oxide materials has been synthesized by a simple low temperature solid-state route with mixed nitrates/urea with glycerol as the starting materials. First we have taken TG/DTA for observing the phase transformations of LiNi{sub 0.9}Ca{sub 0.1}O{sub 2}. The structure of the synthesized oxides was analyzed using X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) to identify the crystal structure and cation environment, respectively. The synthesized ceramic oxide battery materials were examined by using transmission electron microscope (TEM), scanning electron microscope (SEM) analysis to determine the particle size, nature and morphological structure. SEM with energy dispersive X-ray spectroscopic analysis (EDAX) analysis was carried out to explore the composition of the prepared materials. The electrochemical performance of LiNi{sub 1-x}Ca {sub x}O{sub 2} electrodes was analyzed using cyclic voltammetry (CV) and galvanostatic charge-discharge cycling studies in the voltage range 3.0-4.5 V. Electrode made with cathode active material, acetylene black and poly(vinylidene difluoride) yield a discharge capacity of 178.1 mAh g{sup -1} (x = 0.2) with good specific capacity over several charge-discharge cycles. These results have been also supported by cyclic voltammograms.

Sathiyamoorthi, R. [Department of Industrial Chemistry, Alagappa University, Karaikudi 630003 (India); Vasudevan, T. [Department of Industrial Chemistry, Alagappa University, Karaikudi 630003 (India)]. E-mail: ramasathi25@yahoo.com

2007-08-07

103

Method for making an electrochemical cell  

DOEpatents

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.

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

1996-10-22

104

Method for making an electrochemical cell  

DOEpatents

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.

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

1996-01-01

105

Electrochemical cell to measure corrosion rates in noncondensing environments  

SciTech Connect

We have constructedad used an electrochemical cell to estimate corrosion rates in a noncondensing environment, i.e., water-saturated air (100% relative humidity). In this initial effort, we compared the corrosion rates for a variety of metals and alloys in water-saturated air in the electrochemical cell with the corrosion rates of these materials in aerated and deaerated deionized water in an aqueous cell. For most materials, corrosion rates in the humid-air environment were not more than an order of magnitude lower than those in water. Using Faraday's-law calculations, we determined corrosion rates by linear polarization and by Tafel extrapolation. We also measured galvanic potentials and currents between selected dissimilar-metal couples.

Truhan, J.J.; Chen, C.; Kirk, F.C.

1984-10-01

106

Photoelectrolysis of water in semiconductor septum electrochemical photovoltaic cells  

SciTech Connect

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.

Tien, H.T.; Chen, J.W. (Michigan State Univ., East Lansing (United States))

1992-01-01

107

Selectable-Tip Corrosion-Testing Electrochemical Cell  

NASA Technical Reports Server (NTRS)

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.

Lomness, Janice; Hintze, Paul

2008-01-01

108

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

DOEpatents

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.

Gering, Kevin L.

2013-06-18

109

Cobalt(III)-mediated oxidative destruction of phenol using divided electrochemical cell  

Microsoft Academic Search

Mediated electrochemical oxidation is one of the suitable processes for the destruction of hazardous organic compounds and\\u000a the dissolution of nuclear wastes at ambient temperature and pressure. The electrochemical oxidation of Co(II) was carried\\u000a out in an undivided and divided electrochemical cell. The formation of Co(III) was studied in an divided electrochemical cell\\u000a by varying conditions such as temperature and

Manickam Matheswaran; Sang Joon Chung; Il Shik Moon

2008-01-01

110

Electrochemical cell and separator plate thereof  

DOEpatents

A fuel cell includes a separator plate having first and second flow channels extending there through contiguously with an electrode and respectively in flow communication with the cell electrolyte and in flow isolation with respect to such electrolyte. In fuel cell system arrangement, the diverse type channels are supplied in common with process gas for thermal control purposes. The separator plate is readily formed by corrugation of integral sheet material. 10 figs.

Baker, Bernard S.; Dharia, Dilip J.

1979-10-02

111

Electrochemical cell and separator plate thereof  

DOEpatents

A fuel cell includes a separator plate having first and second flow channels extending therethrough contiguously with an electrode and respectively in flow communication with the cell electrolyte and in flow isolation with respect to such electrolyte. In fuel cell system arrangement, the diverse type channels are suplied in common with process gas for thermal control purposes. The separator plate is readily formed by corrugation of integral sheet material.

Baker, Bernard S. (Brookfield Center, CT); Dharia, Dilip J. (Danbury, CT)

1979-01-01

112

Electrochemical deposition of zinc oxide nanorods for hybrid solar cells  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) nanorod arrays for inorganic/organic hybrid solar cells were electrochemically deposited on indium tin oxide (ITO) substrates with a rotating disk electrode setup. The addition of a ZnO seed layer on the ITO prior to electrochemical deposition improved the morphology of the nanorods, resulting in nanorods with smaller and homogenous diameters as well as a higher degree of vertical orientation on to the substrate. The ZnO films deposited on the seeded ITO substrates had higher optical transmittance and lower concentration of defects. Chronoamperometric transient curves show that nucleation and coalescence occurred later for bare ITO substrates, indicating lower densities of initial nuclei, resulting in the growth of nanorods with larger diameters. The solar cell characteristics of the devices fabricated from the seeded ITO substrates were better. The seed layer also acts as a hole-blocking layer, preventing the direct contact between the hole-transporting polymer material and the ITO.

Torres Damasco Ty, Jennifer; Yanagi, Hisao

2015-04-01

113

Electrochemical cell utilizing selenium as an electrode-reactant  

SciTech Connect

This patent describes an electrochemical cell. It comprises: an anolyte containing substantially a molten alkali metal; a solid beta-alumina electrolyte possessing mobile alkali metal ions of the same alkali metal as is present in the anolyte; and a catholyte comprising a mixture of molten selenium and molten sulfur in a molar ration of about 3:1 to about 30:1 selenium to sulfur, wherein at least a portion of the selenium and sulfur is present in elemental form.

Virkar, A.V.; Miller, G.R.; Rasmussen, J.R.

1990-01-23

114

Protective interlayer for high temperature solid electrolyte electrochemical cells  

DOEpatents

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.

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

1986-01-01

115

Protective interlayer for high temperature solid electrolyte electrochemical cells  

DOEpatents

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.

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

1987-01-01

116

Protective interlayer for high temperature solid electrolyte electrochemical cells  

DOEpatents

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.

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

117

Method of making gas diffusion layers for electrochemical cells  

DOEpatents

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.

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

2002-01-01

118

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

DOEpatents

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.

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

2014-12-09

119

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

NASA Technical Reports Server (NTRS)

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.

Gross, S.

1977-01-01

120

Protective interlayer for high temperature solid electrolyte electrochemical cells  

DOEpatents

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.

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

1996-05-14

121

Fuel Cells and Electrochemical Energy Storage.  

ERIC Educational Resources Information Center

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)

Sammells, Anthony F.

1983-01-01

122

Electrochemical cell with high discharge/charge rate capability  

DOEpatents

A fully charged positive electrode composition for an electrochemical cell includes FeS.sub.2 and NiS.sub.2 in about equal molar amounts along with about 2-20 mole percent of the reaction product Li.sub.2 S. Through selection of appropriate electrolyte compositions, high power output or low operating temperatures can be obtained. The cell includes a substantially constant electrode impedance through most of its charge and discharge range. Exceptionally high discharge rates and overcharge protection are obtainable through use of the inventive electrode composition.

Redey, Laszlo (Downers Grove, IL)

1988-01-01

123

Electrochemical cell apparatus having an exterior fuel mixer nozzle  

DOEpatents

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.

Reichner, P.; Doshi, V.B.

1992-12-08

124

Electrochemical hydrogen concentrator for phosphoric acid fuel cells  

NASA Astrophysics Data System (ADS)

The production of high purity hydrogen for use in phosphoric acid fuel cell from heavily contaminated reformed diesel fuel gas using an electrochemical device has been demonstrated. The electrochemical hydrogen separator (EHS) is based on current PAFC technology. Hydrogen is removed from the contaminated gas stream by oxidation to hydrogen ions at a gas diffusion cathode. An anode catalyst with excellent tolerance to high levels of CO and H2S contaminants has been developed. The use of this anode catalyst would allow the EHS device to produce pure hydrogen with minimal voltage impact on the overall PAFC power output. Reduction in size and weight of the PAFC power plant is also indicated through reduced load on fuel processing components.

Giner, Jose; Kackley, Nancy D.

1987-11-01

125

Composite bipolar plate for electrochemical cells  

DOEpatents

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.

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

2001-01-01

126

Electrochemical impedance spectra of solid-oxide fuel cells and polymer membrane fuel cells  

Microsoft Academic Search

Electrochemical impedance spectroscopy (EIS) is a very useful method for the characterization of fuel cells. The anode and cathode transfer functions have been determined independently without a reference electrode using symmetric gas supply of hydrogen or oxygen on both electrodes of the fuel cell at open circuit potential (OCP). EIS are given for both polymer electrolyte fuel cells (PEFC) and

N. Wagner; W. Schnurnberger; B. Müller; M. Lang

1998-01-01

127

Electrochemical behavior of niobium triselenide cathode in lithium secondary cells  

NASA Technical Reports Server (NTRS)

Niobium triselenide cathodes in Li ambient-temperature rechargeable batteries for space applications undergo a topotactic reaction, with three equivalents of Li at high positive potential furnishing high energy density. It also yields good electronic conductivity, a long life cycle, and high diffusivity for Li. An attempt is presently made to characterize the intercalation mechanism between Li and NbSe3 by means of an ac impedance study conducted at various charge stages in the process of SbSe3 reduction. An effort is also made to predict the charge state of NbSe3 nondestructively, on the basis of the impedance parameters.

Ratnakumar, B. V.; Di Stefano, S.; Bankston, C. P.

1988-01-01

128

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

E-print Network

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, with emphasis on the principle and performance of batteries, supercapacitors and fuel cells. The objective

Rubloff, Gary W.

129

Pore size engineering applied to starved electrochemical cells and batteries  

NASA Technical Reports Server (NTRS)

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.

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

1982-01-01

130

Method of electrode fabrication for solid oxide electrochemical cells  

DOEpatents

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.

Jensen, R.R.

1990-11-20

131

Method of electrode fabrication for solid oxide electrochemical cells  

DOEpatents

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.

Jensen, Russell R. (Murrysville, PA)

1990-01-01

132

Scanning electrochemical cell microscopy platform for ultrasensitive photoelectrochemical imaging.  

PubMed

The development of techniques for nanoscale structure-activity correlations is of major importance for the fundamental understanding and rational design of (photo)electrocatalysts. However, the low conversion efficiency of characteristic materials generates tiny photoelectrochemical currents at the submicrometer to nanoscale, in the fA range, which are challenging to detect and measure accurately. Here, we report the coupling of scanning electrochemical cell microscopy (SECCM) with photoillumination, to create a submicrometer spatial resolution cell that opens up high resolution structure-(photo)activity measurements. We demonstrate the capabilities of the technique as a tool for: (i) high spatial resolution (photo)activity mapping using an ionic liquid electrolyte at a thin film of TiO2 aggregates, commonly used as a photoanode in dye sensitized solar cells (DSSCs) and (ii) in situ (photo)activity measurements of an electropolymerized conjugated polymer on a transparent Au substrate in a controlled atmospheric environment. Quantitative data, including localized (photo)electrochemical transients and external quantum efficiency (EQE), are extracted, and prospects for further technique development and enhancement are outlined. PMID:25797893

Aaronson, Barak D B; Byers, Joshua C; Colburn, Alex W; McKelvey, Kim; Unwin, Patrick R

2015-04-21

133

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

PubMed Central

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

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

134

Cell structure for electrochemical devices and method of making same  

DOEpatents

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.

Kaun, Thomas D.

2007-03-27

135

Battery paste compositions and electrochemical cells for use therewith  

DOEpatents

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.

Olson, John B. (Boulder, CO)

1999-02-16

136

Battery paste compositions and electrochemical cells for use therewith  

DOEpatents

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.

Olson, J.B.

1999-02-16

137

Battery paste compositions and electrochemical cells for use therewith  

DOEpatents

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.

Olson, John B. (Boulder, CO)

1999-12-07

138

Electrochemically Reduced Water Protects Neural Cells from Oxidative Damage  

PubMed Central

Aging-related neurodegenerative disorders are closely associated with mitochondrial dysfunction and oxidative stresses and their incidence tends to increase with aging. Brain is the most vulnerable to reactive species generated by a higher rate of oxygen consumption and glucose utilization compared to other organs. Electrochemically reduced water (ERW) was demonstrated to scavenge reactive oxygen species (ROS) in several cell types. In the present study, the protective effect of ERW against hydrogen peroxide (H2O2) and nitric oxide (NO) was investigated in several rodent neuronal cell lines and primary cells. ERW was found to significantly suppress H2O2 (50–200??M) induced PC12 and SFME cell deaths. ERW scavenged intracellular ROS and exhibited a protective effect against neuronal network damage caused by 200??M H2O2 in N1E-115 cells. ERW significantly suppressed NO-induced cytotoxicity in PC12 cells despite the fact that it did not have the ability to scavenge intracellular NO. ERW significantly suppressed both glutamate induced Ca2+ influx and the resulting cytotoxicity in primary cells. These results collectively demonstrated for the first time that ERW protects several types of neuronal cells by scavenging ROS because of the presence of hydrogen and platinum nanoparticles dissolved in ERW. PMID:25383141

Hamasaki, Takeki; Kinjo, Tomoya; Nakamichi, Noboru; Teruya, Kiichiro; Kabayama, Shigeru

2014-01-01

139

Materials development and electrochemical characterization of polymer electrolyte fuel cells  

NASA Astrophysics Data System (ADS)

In this thesis, the materials development and mechanism characterizations of polymer electrolyte fuel cells (PEFCs) are addressed. This work starts with a new preparation technique for a modified electrode structure containing two carbon support materials. The resulted catalyzed electrode, which exhibits good materials properties, demonstrates an improved kinetics in the oxygen reduction reaction (ORR). A new electrocatalyst synthesis procedure utilizing an amphiphilic surfactant to stabilize the nanophase catalyst particles is proposed to fabricate the Pt and Pt-Ru electrocatalysts supported on carbon powders. Physicochemical and electrochemical characterizations of this electrocatalyst show that the nanmeter-scale, well-dispersed catalyst with a high catalytic activity can be obtained. In addition to developing the electrocatalytic materials, an electrochemical impedance based study, aiming to achieve a better understanding of the H 2/CO and methanol oxidation mechanism, is carried out. Unlike the equivalent circuit fitting model frequently used in the fuel cell community, a mathematical simulation tool, utilizing the impedance theory and the reaction kinetics, is developed. This model not only successfully predicts the effects of applied potentials to the impedance but also captures most of the impedance characteristics found in the experiments. In particular, the occurrence of the "pseudo inductive" behavior observed both in the experiments and simulations can be used as an effective criterion for the onset of surface CO oxidation. It is believed that the simulation strategy employed in this study can be utilized to assist the materials design of electrocatalysts with improved CO tolerance and high electrocatalytic activity.

Wang, Xin

140

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

PubMed Central

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

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

2012-01-01

141

Microfabricated electrochemical cell-based biosensors for analysis of living cells in vitro.  

PubMed

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

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

2012-01-01

142

Organic electrochemical transistors for cell-based impedance sensing  

NASA Astrophysics Data System (ADS)

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.

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

2015-01-01

143

Stabilizing metal components in electrodes of electrochemical cells  

DOEpatents

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.

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

1989-01-01

144

Fabrication of solid oxide fuel cell by electrochemical vapor deposition  

DOEpatents

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.

Riley, B.; Szreders, B.E.

1988-04-26

145

Electrochemical impedance spectroscopic analysis of dye-sensitized solar cells.  

PubMed

Electrochemical impedance spectroscopy (EIS) has been performed to investigate electronic and ionic processes in dye-sensitized solar cells (DSC). A theoretical model has been elaborated, to interpret the frequency response of the device. The high-frequency feature is attributed to the charge transfer at the counter electrode while the response in the intermediate-frequency region is associated with the electron transport in the mesoscopic TiO2 film and the back reaction at the TiO2/electrolyte interface. The low-frequency region reflects the diffusion in the electrolyte. Using an appropriate equivalent circuit, the electron transport rate and electron lifetime in the mesoscopic film have been derived, which agree with the values derived from transient photocurrent and photovoltage measurements. The EIS measurements show that DSC performance variations under prolonged thermal aging result mainly from the decrease in the lifetime of the conduction band electron in the TiO2 film. PMID:16852893

Wang, Qing; Moser, Jacques-E; Grätzel, Michael

2005-08-11

146

Fabrication of solid oxide fuel cell by electrochemical vapor deposition  

DOEpatents

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.

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

1989-01-01

147

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

DOEpatents

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.

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

148

[An electrochemical cell for end-column amperometric detection in capillary electrophoresis].  

PubMed

With end-column electrochemical detection in capillary electrophoresis(CE), precise positioning and stabilization of the working electrode are very important. In this paper, an electrochemical cell designed for end-colunm wall-jet amperometric detection in capillary zone electrophoresis is reported. In this cell, a curved surface was formed because of the surface tension and used as the amplifier. With this cell, alignment of the working electrode with the capillary outlet could be achieved precisely and easily without the help of a microscope and a micropositioner. Being compared with electrochemical cell of other groups, this cell is simple and can be used more conveniently. Application of this electrochemical cell for electrophoretic separation of phenols is demonstrated. High resolution and low detection limits were obtained with this assembly. PMID:12549166

Wu, X; Fang, A; Zhang, X

1999-03-01

149

Engineering Recently, we created the first Li-ion electrochemical cell  

E-print Network

for understanding important processes in Li-ion batteries. For example, liquid cells are required in order to examine the electrochemical reactions between battery materials and the standard battery electrolytes and electrochemical studies on conventional battery electrodes and highlight how in-situ studies can have important

150

Extension of Newman's method to electrochemical reactiondiffusion in a fuel cell catalyst layer  

E-print Network

Extension of Newman's method to electrochemical reaction±diffusion in a fuel cell catalyst layer for electrochemical reactions occurring in the porous electrode [1]. Newman discussed the numerical solution is called Newman's Band(j). White discussed Newman's method, and promoted this technique for wide

151

Supported liquid membrane electrochemical separators  

DOEpatents

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.

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

1986-01-01

152

Electroendocytosis Is Driven by the Binding of Electrochemically Produced Protons to the Cell’s Surface  

PubMed Central

Electroendocytosis involves the exposure of cells to pulsed low electric field and is emerging as a complementary method to electroporation for the incorporation of macromolecules into cells. The present study explores the underlying mechanism of electroendocytosis and its dependence on electrochemical byproducts formed at the electrode interface. Cell suspensions were exposed to pulsed low electric field in a partitioned device where cells are spatially restricted relative to the electrodes. The cellular uptake of dextran-FITC was analyzed by flow cytometery and visualized by confocal microscopy. We first show that uptake occurs only in cells adjacent to the anode. The enhanced uptake near the anode is found to depend on electric current density rather than on electric field strength, in the range of 5 to 65 V/cm. Electrochemically produced oxidative species that impose intracellular oxidative stress, do not play any role in the stimulated uptake. An inverse dependence is found between electrically induced uptake and the solution’s buffer capacity. Electroendocytosis can be mimicked by chemically acidifying the extracellular solution which promotes the enhanced uptake of dextran polymers and the uptake of plasmid DNA. Electrochemical production of protons at the anode interface is responsible for inducing uptake of macromolecules into cells exposed to a pulsed low electric field. Expanding the understanding of the mechanism involved in electric fields induced drug-delivery into cells, is expected to contribute to clinical therapy applications in the future. PMID:23209699

Ben-Dov, Nadav; Rozman Grinberg, Inna; Korenstein, Rafi

2012-01-01

153

Eliminating degradation in solid oxide electrochemical cells by reversible operation.  

PubMed

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

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

2015-02-01

154

Eliminating degradation in solid oxide electrochemical cells by reversible operation  

NASA Astrophysics Data System (ADS)

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.

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

2015-02-01

155

Suppressing The Growth Of Dendrites In Secondary Li Cells  

NASA Technical Reports Server (NTRS)

Proposed technique for suppressing growth of lithium dendrites in rechargeable lithium electrochemical power cells involves periodic interruption of steady charging current with short, high-current discharge pulses. Technique applicable to lithium cells of several different types, including Li/TiS(2), Li/NbSe(3), Li/CoO(2), Li/MoS(2), Li/Vo(x), and Li/MnO(2). Cells candidates for use in spacecraft, military, communications, automotive, and other applications in which high-energy-density rechargeable batteries needed.

Davies, Evan D.; Perrone, David E.; Shen, David H.

1996-01-01

156

Air electrode material for high temperature electrochemical cells  

DOEpatents

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.

Ruka, Roswell J. (Churchill Boro, PA)

1985-01-01

157

Support tube for high temperature solid electrolyte electrochemical cell  

DOEpatents

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.

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

1986-01-01

158

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

SciTech Connect

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.

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

2003-01-27

159

Direct In Vivo Electrochemical Detection of Haemoglobin in Red Blood Cells  

E-print Network

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 ...

Toh, Rou Jun

160

Cycle life test of secondary spacecraft cells  

NASA Technical Reports Server (NTRS)

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.

Harkness, J. D.

1980-01-01

161

Stainless steel electrode characterizations by electrochemical impedance spectroscopy for dye-sensitized solar cells  

Microsoft Academic Search

Electrochemical impedance spectroscopy (EIS) was used to understand the electrochemical mechanisms which appear in dye-sensitized solar cells (DSSCs). This qualitative and quantitative technique permits identification of the phenomena proceeding within the different elements composing the cell and at their interfaces.In this study, the classical conducting glass substrate was replaced by a protected stainless steel (304 type) substrate as the counter-electrode

A.-F. Kanta; A. Decroly

2011-01-01

162

Evaluation program for secondary spacecraft cells  

NASA Technical Reports Server (NTRS)

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.

Harkness, J. D.

1975-01-01

163

Plant Cells: Secondary Metabolite Heterogeneity and Its Manipulation  

Microsoft Academic Search

This chapter proposes the concept of rational manipulation of secondary metabolite heterogeneity\\u000a in plant cell cultures. The heterogeneity of plant secondary metabolites is a very interesting\\u000a and important issue because these structure-similar natural products have different biological activities.\\u000a Both taxoids and ginsenosides are two kinds of preeminent examples in the enormous reservoir of pharmacologically\\u000a valuable heterogeneous molecules in the plant kingdom.

Jian-Jiang Zhong; Cai-Jun Yue

164

Electrochemical concentration cell ozonesonde performance evaluation during STOIC 1989  

NASA Astrophysics Data System (ADS)

Electrochemical concentration cell (ECC) ozonesondes flown by NOAA and NASA Wallops Flight Facility (WFF) personnel during the Stratospheric Ozone Intercomparison Campaign (STOIC) conducted at the Jet Propulsion Laboratory's Table Mountain Facility, Wrightwood, California, July 21 to August 1, 1989, exhibited highly similar ozone measurement precisions and accuracies even though considerably different methods were used by the two research groups in preparing the instruments for use and in calibrating the instruments. The Table Mountain data as well as data obtained in the past showed the precisions to range from about ±3 to ±12% in the troposphere, remain relatively constant at ±3% in the stratosphere to 10 mbar, then decrease to about ±10% at 4-mbar pressure altitude. Corresponding ozone measurement accuracies for individual ozonesonde soundings were estimated to be about ±6% near the ground, decrease to -7 to 17% in the high troposphere where ozone concentrations are low, increase to about ±5% in the low stratosphere and remain so to an altitude of about 10 mbar (˜32 km), then decrease to -14 to 6% at 4 mbar (˜38 km) where ozone concentrations are again low. Stratospheric ozone measurements were also made during STOIC with ground-based lidars and a microwave radiometer that will be used for ozone measurements in the future at sites of the Network for the Detection of Stratospheric Change (NDSC). The ECC ozonesonde observations provided useful comparison data for evaluating the performance of the lidar and microwave instruments.

Komhyr, W. D.; Barnes, R. A.; Brothers, G. B.; Lathrop, J. A.; Opperman, D. P.

1995-05-01

165

Evolutionary diversification of secondary mechanoreceptor cells in tunicata  

PubMed Central

Background Hair cells are vertebrate secondary sensory cells located in the ear and in the lateral line organ. Until recently, these cells were considered to be mechanoreceptors exclusively found in vertebrates that evolved within this group. Evidence of secondary mechanoreceptors in some tunicates, the proposed sister group of vertebrates, has recently led to the hypothesis that vertebrate and tunicate secondary sensory cells share a common origin. Secondary sensory cells were described in detail in two tunicate groups, ascidians and thaliaceans, in which they constitute an oral sensory structure called the coronal organ. Among thaliaceans, the organ is absent in salps and it has been hypothesised that this condition is due to a different feeding system adopted by this group of animals. No information is available as to whether a comparable structure exists in the third group of tunicates, the appendicularians, although different sensory structures are known to be present in these animals. Results We studied the detailed morphology of appendicularian oral mechanoreceptors. Using light and electron microscopy we could demonstrate that the mechanosensory organ called the circumoral ring is composed of secondary sensory cells. We described the ultrastructure of the circumoral organ in two appendicularian species, Oikopleura dioica and Oikopleura albicans, and thus taxonomically completed the data collection of tunicate secondary sensory cells. To understand the evolution of secondary sensory cells in tunicates, we performed a cladistic analysis using morphological data. We constructed a matrix consisting of 19 characters derived from detailed ultrastructural studies in 16 tunicate species and used a cephalochordate and three vertebrate species as outgroups. Conclusions Our study clearly shows that the circumoral ring is the appendicularian homologue of the coronal organ of other tunicate taxa. The cladistic analysis enabled us to reconstruct the features of the putative ancestral hair cell in tunicates, represented by a simple monociliated cell. This cell successively differentiated into the current variety of oral mechanoreceptors in the various tunicate lineages. Finally, we demonstrated that the inferred evolutionary changes coincide with major transitions in the feeding strategies in each respective lineage. PMID:23734698

2013-01-01

166

Photocured Gelled Electrolytes For Secondary Li Cells  

NASA Technical Reports Server (NTRS)

Class of photocured polymers exhibiting lithium-ion conductivities greater than those of well-studied polymers based on polyethylene oxide (PEO) show promise as polymeric electrolytes in rechargeable lithium cells. Increase in conductivity occasioned by use of electrolytes, coupled with amenability of electrolytes to formation into uniform thin (less than 25 micrometers thick), wide films, expected to result in cells with power densities greater than 100 W h/kg and charge/discharge rates exceeding currents equal, in amperes, to ampere-hour ratings. All-solid-state lithium batteries containing these electrolytes used as high-power, high-rate rechargeable power sources in commercial and aerospace applications.

Nagasubramanian, Ganesan

1994-01-01

167

J. Electrochem. Soc., in press (1998) Micro-Macroscopic Coupled Modeling of Batteries and Fuel Cells  

E-print Network

Cells Part 1. Model Development C.Y. Wang1 and W.B. Gu Department of Mechanical Engineering and interface morphology and chemistry, has been developed for advanced batteries and fuel cells. Electrochemical cells considered consist of three phases: a solid matrix (electrode material or separator

Wang, Chao-Yang

168

J. Electrochem. Soc., in press (1998) MicroMacroscopic Coupled Modeling of Batteries and Fuel Cells  

E-print Network

Cells Part 1. Model Development C.Y. Wang 1 and W.B. Gu Department of Mechanical Engineering materials and interface morphology and chemistry, has been developed for advanced batteries and fuel cells. Electrochemical cells considered consist of three phases: a solid matrix (electrode material or separator

Wang, Chao-Yang

169

TAS-2013-0043 1 Abstract--Fuel cells are electrochemical energy converters  

E-print Network

TAS-2013-0043 1 Abstract--Fuel cells are electrochemical energy converters which allow generation. Fuel cells are then by essence low voltage sources , so that for most practical applications of the perfectly direct current relies upon a fuel cell fed by hydrogen. The main advantages to be taken from fuel

Boyer, Edmond

170

Algorithm Development for Electrochemical Impedance Spectroscopy Diagnostics in PEM Fuel Cells  

E-print Network

Algorithm Development for Electrochemical Impedance Spectroscopy Diagnostics in PEM Fuel Cells Abstract The purpose of this work is to develop algorithms to identify fuel cell faults using-board fuel cell diagnostic hardware. Impedance can identify faults that cannot be identified solely by a drop

Victoria, University of

171

Comparison of High-Throughput Electrochemical Methods for Testing Direct Methanol Fuel Cell Anode Electrocatalysts  

E-print Network

manuscript received August 21, 2004. Available electronically January 28, 2005. The efficiency of a fuel cellComparison of High-Throughput Electrochemical Methods for Testing Direct Methanol Fuel Cell Anode The screening and testing of fuel cell electrocatalysts often involves comparisons under conditions that do

172

On-off switches for secondary cell wall biosynthesis.  

PubMed

Secondary cell walls provide plants with rigidity and strength to support their body weight and ensure water and nutrient transport. They also provide textiles, timber, and potentially second-generation biofuels for human use. Genes responsible for synthesis of the different cell wall components, namely cellulose, hemicelluloses, and lignin, are coordinately expressed and under transcriptional regulation. In the past several years, cell wall-related NAC and MYB transcription factors have been intensively investigated in different species and shown to be master switches of secondary cell wall biosynthesis. Positive and negative regulators, which function upstream of NAC master switches, have also been identified in different plant tissues. Further elucidation of the regulatory mechanisms of cell wall synthesis will facilitate the engineering of plant feedstocks suitable for biofuel production. PMID:22138968

Wang, Huan-Zhong; Dixon, Richard A

2012-03-01

173

Electrochemical and spectroscopic studies of fuel cell reactions  

NASA Astrophysics Data System (ADS)

Fuel cells, especially proton exchange membrane fuel cells (PEMFCs) are expected soon to become a major source of clean energy. However, the sluggish kinetics of the fuel cell reactions, i.e., the fuel oxidation and oxygen reduction, hinders the wide-spread application of PEMFCs. These problems prompted our studies to focus on elucidating the nature of the reaction intermediates during the oxidation of fuels and the reduction of oxygen on electrocatalysts, and understanding the mechanisms of these reactions. The results from these studies will provide basic information for designing new electrocatalysts. In this dissertation, the oxidation reactions of ethanol and dimethyl ether (DME) on Pt were investigated by the surface enhanced infrared absorption spectroscopy with an attenuated total reflection configuration (ATR-SEIRAS). Various reaction intermediates were detected and their electrochemical behaviors were studied. We also benefited from advantages of the ATR-SEIRAS technique and observed superoxide anion (O2-) and hydrogen peroxide anion (H2-) as the intermediates in the oxygen reduction reaction (ORR) on Pt and Au electrodes for the first time. The other main goal of this study is design of new electrocatalysts for ORR with low cost and high activity. Two novel electrocatalysts were developed. One is Pt monolayer electrocatalysts consisting of a Pt monolayer formed by a red-ox replacement of the Cu monolayer by Pt atoms on non-noble metal-noble metal core-shell nanoparticles. In such catalyst, the total noble mass activity of the catalyst was 2--6 times larger that of commercial Pt catalyst. Another way of lowering the cost of catalysts and enhancing the ORR activity involves alloying less expensive noble metals with other non-noble elements. In this dissertation, the nano-structured Pd based alloy electrocatalysts have been explored. The results showed that their ORR activities surpass that of commercial Pt. The density functional theory (DFT) calculations were carried out to address the possible mechanisms for the observed enhancement. The volcano-type dependence of the ORR activity on the d-band center of the noble metal overlayer was established. These results indicate a way for designing new catalysts with greatly improved properties.

Shao, Minhua

174

Bringing light to solid-state electrolytes: The polymer light-emitting electrochemical cell  

Microsoft Academic Search

A brief review is given on the operational mechanism and performance of various types of polymer light-emitting electrochemical cells (LECs). We discuss two key characteristics of LECs—the turn-on time and the operational lifetime—in the context of ion mobility, phase separation and electrochemical stability, and we propose that, with the appropriate selection of materials and pre-treatment, ternary {polymer+small molecule+salt} and single-component

Ludvig Edman

2005-01-01

175

Electrochemical photovoltaic cells. Project 65039 quarterly technical progress report, April 15-July 31, 1980  

SciTech Connect

Liquid-junction photoelectrochemical cells can be used either for the direct conversion of solar energy to electricity or to generate stored chemical species available for later electrochemical discharge. The objectives of this program are to identify experimental approaches for electrochemical photovoltaic cells that not only show promise of high power-conversion efficiencies but also have the potential to achieve long life and the capacity for energy storage. The work is organized as follows: (1) selection of high-efficiency semiconductor photoelectrode/electrolyte systems, (2) development of long-life electrochemical photovoltaic cells, (3) all solid-state electrochemical photovoltaic cell with in situ storage, and (4) demonstration of laboratory-size photoelectrochemical cell with redox storage. This program is directed toward identifying a suitable match between the proposed semiconductor and the redox species present in aqueous, nonaqueous, and solid electrolytes for achieving the necessary performance and semiconductor stability requirements. Emphasis is on aqueous electrolyte-based systems where fast kinetics are favored. The proposed systems will be compatible with convenient storage of the electroactive species generated and its later electrochemical discharge in a redox cell. Progress is reported.

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

1980-09-01

176

In Proc of Direct Methanol Fuel Cell Symposium, 199th Electrochem.l Soc. Mtg, Washington DC, 3/01.  

E-print Network

In Proc of Direct Methanol Fuel Cell Symposium, 199th Electrochem.l Soc. Mtg, Washington DC, 3/01. MATHEMATICAL MODELING OF LIQUID-FEED DIRECT METHANOL FUEL CELLS Z. H. Wang and C. Y. Wang Electrochemical methanol fuel cells (DMFC). Diffusion and convection of both gas and liquid phases are considered

Wang, Chao-Yang

177

Toxicity of graphene nanoflakes evaluated by cell-based electrochemical impedance biosensing.  

PubMed

Graphene nanoflake toxicity was analyzed using cell-based electrochemical impedance biosensing with interdigitated indium tin oxide (ITO) electrodes installed in a custom-built mini-incubator positioned on an inverted optical microscope. Sensing with electrochemical measurements from interdigitated ITO electrodes was highly linear (R(2)?=?0.93 and 0.96 for anodic peak current (Ipa) and cathodic peak current (Ipc), respectively). Size-dependent analysis of Graphene nanoflake toxicity was carried out in a mini-incubator system with cultured HeLa cells treated with Graphene nanoflakes having an average size of 80 or 30 nm for one day. Biological assays of cell proliferation and viability complemented electrochemical impedance measurements. The increased toxicity of smaller Graphene nanoflakes (30 nm) as measured by electrochemical impedance sensing and optical monitoring of treated cells was consistent with the biological assay results. Cell-based electrochemical impedance biosensing can be used to assess the toxicity of nanomaterials with different biomedical and environmental applications. PMID:23894129

Yoon, Ok Ja; Kim, Insu; Sohn, Il Yung; Kieu, Truong Thuy; Lee, Nae-Eung

2014-07-01

178

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

PubMed

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

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

2013-09-17

179

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

PubMed

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

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

2015-04-01

180

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

ERIC Educational Resources Information Center

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…

Ivey, Michelle M.; Smith, Eugene T.

2008-01-01

181

Enhanced electrochemical nanoring electrode for analysis of cytosol in single cells.  

PubMed

A microelectrode array has been applied for single cell analysis with relatively high throughput; however, the cells were typically cultured on the microelectrodes under cell-size microwell traps leading to the difficulty in the functionalization of an electrode surface for higher detection sensitivity. Here, nanoring electrodes embedded under the microwell traps were fabricated to achieve the isolation of the electrode surface and the cell support, and thus, the electrode surface can be modified to obtain enhanced electrochemical sensitivity for single cell analysis. Moreover, the nanometer-sized electrode permitted a faster diffusion of analyte to the surface for additional improvement in the sensitivity, which was evidenced by the electrochemical characterization and the simulation. To demonstrate the concept of the functionalized nanoring electrode for single cell analysis, the electrode surface was deposited with prussian blue to detect intracellular hydrogen peroxide at a single cell. Hundreds of picoamperes were observed on our functionalized nanoring electrode exhibiting the enhanced electrochemical sensitivity. The success in the achievement of a functionalized nanoring electrode will benefit the development of high throughput single cell electrochemical analysis. PMID:25365743

Zhuang, Lihong; Zuo, Huanzhen; Wu, Zengqiang; Wang, Yu; Fang, Danjun; Jiang, Dechen

2014-12-01

182

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

NASA Technical Reports Server (NTRS)

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.

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

1979-01-01

183

Overcharge and overdischarge protection of ambient temperature secondary lithium cells  

NASA Technical Reports Server (NTRS)

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.

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

1994-01-01

184

Human natural killer cell development in secondary lymphoid tissues.  

PubMed

For nearly a decade it has been appreciated that critical steps in human natural killer (NK) cell development likely occur outside of the bone marrow and potentially necessitate distinct microenvironments within extramedullary tissues. The latter include the liver and gravid uterus as well as secondary lymphoid tissues such as tonsils and lymph nodes. For as yet unknown reasons these tissues are naturally enriched with NK cell developmental intermediates (NKDI) that span a maturation continuum starting from an oligopotent CD34(+)CD45RA(+) hematopoietic precursor cell to a cytolytic mature NK cell. Indeed despite the detection of NKDI within the aforementioned tissues, relatively little is known about how, why, and when these tissues may be most suited to support NK cell maturation and how this process fits in with other components of the human immune system. With the discovery of other innate lymphoid subsets whose immunophenotypes overlap with those of NKDI, there is also need to revisit and potentially re-characterize the basic immunophenotypes of the stages of the human NK cell developmental pathway in vivo. In this review, we provide an overview of human NK cell development in secondary lymphoid tissues and discuss the many questions that remain to be answered in this exciting field. PMID:24661538

Freud, Aharon G; Yu, Jianhua; Caligiuri, Michael A

2014-04-01

185

A novel LTCC electrochemical cell construction and characterization: a detection compartment for portable devices.  

PubMed

In this work we described for the first time the construction of a 25 ?L electrochemical cell from low temperature co-fired ceramic (LTCC) material and carbon screen-printed electrode applicable in portable devices. Firstly, a carbon screen-printed electrode was prepared and characterized by cyclic voltammetry and scanning electron microscopy. Afterwards carbon polymeric film and metal pastes were dropped into the LTCC cell cavities in order to determine the device electrodes, and this arrangement was also electrochemically characterized. The great advantage of this promising device is the simple construction method and its widespread applicability in reusable portable devices. PMID:23748910

Pesquero, Naira Canevarolo; Gongora-Rubio, Mário Ricardo; Yamanaka, Hideko

2013-08-01

186

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

SciTech Connect

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.

Binder, M.; Walker, C.W.

1988-05-20

187

Electrochemical behavior of CrN coating for polymer electrolyte membrane fuel cell  

NASA Astrophysics Data System (ADS)

CrN films on a bipolar plate in polymer electrolyte membrane fuel cells have several advantages owing to their excellent corrosion resistance and mechanical properties. Three CrN samples deposited at various radio frequency (RF) powers by RF magnetron sputtering were evaluated under potentiodynamic, potentiostatic and electrochemical impedance spectroscopy conditions. The electrochemical impedance spectroscopy data were monitored for 168 h in a corrosive environment at 70 °C to determine the coating performance at +600 mVSCE under simulated cathodic conditions in a polymer electrolyte membrane fuel cell. The electrochemical behavior of the coatings increased with decreasing RF power. CrN films on the AISI 316 stainless steel substrate showed high protective efficiency and charge transfer resistance, i.e. increasing corrosion resistance with decreasing RF power. X-ray diffraction confirmed the formation of a CrN(200) preferred orientation at low RF power.

Nam, N. D.; Park, I. J.; Kim, J. G.; Tai, P. H.; Yoon, D. H.

2010-05-01

188

A zoom into the nanoscale texture of secondary cell walls  

PubMed Central

Background Besides classical utilization of wood and paper, lignocellulosic biomass has become increasingly important with regard to biorefinery, biofuel production and novel biomaterials. For these new applications the macromolecular assembly of cell walls is of utmost importance and therefore further insights into the arrangement of the molecules on the nanolevel have to be gained. Cell wall recalcitrance against enzymatic degradation is one of the key issues, since an efficient degradation of lignocellulosic plant material is probably the most crucial step in plant conversion to energy. A limiting factor for in-depth analysis is that high resolution characterization techniques provide structural but hardly chemical information (e.g. Transmission Electron Microscopy (TEM), Atomic Force Microscopy (AFM)), while chemical characterization leads to a disassembly of the cell wall components or does not reach the required nanoscale resolution (Fourier Tranform Infrared Spectroscopy (FT-IR), Raman Spectroscopy). Results Here we use for the first time Scanning Near-Field Optical Microscopy (SNOM in reflection mode) on secondary plant cell walls and reveal a segmented circumferential nanostructure. This pattern in the 100 nm range was found in the secondary cell walls of a softwood (spruce), a hardwood (beech) and a grass (bamboo) and is thus concluded to be consistent among various plant species. As the nanostructural pattern is not visible in classical AFM height and phase images it is proven that the contrast is not due to changes in surfaces topography, but due to differences in the molecular structure. Conclusions Comparative analysis of model substances of casted cellulose nanocrystals and spin coated lignin indicate, that the SNOM signal is clearly influenced by changes in lignin distribution or composition. Therefore and based on the known interaction of lignin and visible light (e.g. fluorescence and resonance effects), we assume the elucidated nanoscale structure to reflect variations in lignification within the secondary cell wall. PMID:24410854

2014-01-01

189

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

PubMed

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

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

2013-06-15

190

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

NASA Astrophysics Data System (ADS)

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.

Jiang, Rongzhong

2007-07-01

191

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

DOEpatents

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.

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

2010-11-23

192

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

DOEpatents

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.

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

2010-03-02

193

High strength porous support tubes for high temperature solid electrolyte electrochemical cells  

DOEpatents

A high temperature, solid electrolyte electrochemical cell is made, having an electrode and a solid electrolyte disposed on a porous, sintered support material containing thermally stabilized zirconia powder particles and from about 3 wt. % to about 45 wt. % of thermally stable oxide fibers.

Rossing, Barry R. (Churchill, PA); Zymboly, Gregory E. (Penn Hills, PA)

1986-01-01

194

Free Energies of Formation Measurements on Solid-State Electrochemical Cells  

ERIC Educational Resources Information Center

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)

Rollino, J. A.; Aronson, S.

1972-01-01

195

An electrochemical-based fuel-cell model suitable for electrical engineering automation approach  

Microsoft Academic Search

This paper presents a dynamic electrochemical model for representation, simulation, and evaluation of performance of small size generation systems emphasizing particularly proton exchange membrane fuel-cell (PEMFC) stacks. The results of the model are used to predict the output voltage, efficiency, and power of FCs as a function of the actual load current and of the constructive and operational parameters of

Jeferson M. Corrêa; Felix A. Farret; Luciane N. Canha; Marcelo G. Simões

2004-01-01

196

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

ERIC Educational Resources Information Center

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.…

Yuruk, Nejla; Geban, Omer

197

The Effect of Supplementing Instruction with Conceptual Change Texts on Students' Conceptions of Electrochemical Cells  

ERIC Educational Resources Information Center

The aim of this study was to investigate the effectiveness of instruction supplemented by conceptual change texts (CCTs) over traditional instruction on students' understanding of electrochemical (galvanic and electrolytic) cell concepts. The participants of the study consisted of 64 students from the two classes of a high school located in…

Yuruk, Nejla

2007-01-01

198

Method of making circulating electrolyte electrochemical cell having gas depolarized cathode with hydrophobic barrier layer  

Microsoft Academic Search

A method is described of making a gas depolarized cathode particularly adapted for use in a circulating electrolyte electrochemical cell comprising: (a) forming a carbonized fiber ribbed porous substrate; (b) press-molding a self-supporting layer of a fluorocarbon polymer that contains carbon particles; (c) applying a layer of an oxygen reducing catalyst on one side of the flurocarbon polymer layer; and

G. A. Gruver; H. R. Kunz

1987-01-01

199

Electrochemically Deposited Cadmium Electrode for Sealed Ni-cd Cells  

NASA Technical Reports Server (NTRS)

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.

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

1984-01-01

200

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

DOEpatents

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.

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

1992-01-14

201

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

NASA Technical Reports Server (NTRS)

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.

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

1997-01-01

202

Characterizing Ion Profiles in Dynamic Junction Light-Emitting Electrochemical Cells  

SciTech Connect

Organic semiconductors have the unique ability to conduct both ionic and electronic charge carriers in thin films, an emerging advantage in applications such as light-emitting devices, transistors, and electrochromic devices, among others. Evidence suggests that the profiles of ions and electrochemical doping in the polymer film during operation significantly impact the performance and stability of the device. However, few studies have directly characterized ion profiles within LECs. Here, we present profiles of ion distributions in LECs following application of voltage, via time-of-flight secondary ion mass spectrometry. Ion distributions were characterized with regard to film thickness, salt concentration, applied voltage, and relaxation over time. Results provide insight into the correlation between ion profiles and device performance, as well as potential approaches to tuning electrochemical doping processes in LECs.

Shoji, Tyko D.; Zhu, Zihua; Leger, Janelle M.

2013-11-27

203

Scanning electrochemical microscopy of menadione-glutathione conjugate export from yeast cells  

PubMed Central

The uptake of menadione (2-methyl-1,4-naphthoquinone), which is toxic to yeast cells, and its expulsion as a glutathione complex were studied by scanning electrochemical microscopy. The progression of the in vitro reaction between menadione and glutathione was monitored electrochemically by cyclic voltammetry and correlated with the spectroscopic (UV–visible) behavior. By observing the scanning electrochemical microscope tip current of yeast cells suspended in a menadione-containing solution, the export of the conjugate from the cells with time could be measured. Similar experiments were performed on immobilized yeast cell aggregates stressed by a menadione solution. From the export of the menadione-glutathione conjugate detected at a 1-?m-diameter electrode situated 10 ?m from the cells, a flux of about 30,000 thiodione molecules per second per cell was extracted. Numerical simulations based on an explicit finite difference method further revealed that the observation of a constant efflux of thiodione from the cells suggested the rate was limited by the uptake of menadione and that the efflux through the glutathione-conjugate pump was at least an order of magnitude faster. PMID:15148374

Mauzeroll, Janine; Bard, Allen J.

2004-01-01

204

Electrochemical studies on niobium triselenide cathode material for lithium rechargeable cells  

NASA Technical Reports Server (NTRS)

The electrochemical behavior of NbSe3 in the battery electrolyte 1.5M LiAsF6/2Me-THF is reported. A detailed study has been carried out using various ac and dc electrochemical techniques to establish the mechanism of intercalation of three equivalents of Li with NbSe3 as well as the rate governing processes in the reduction of NbSe3. An equivalent circuit has been formulated to represent the NbSe3-solution interface. The kinetic parameters for the reduction of NbSe3 were evaluated from the ac and dc measurements. The structural change in NbSe3 on lithiation during initial discharge which results in higher cell voltages and different electrochemical response as compared to virgin NbSe3 was identified to be a loss of crystallographic order.

Ratnakumar, B. V.; Ni, C. L.; Di Stefano, S.; Nagasubramanian, G.; Bankston, C. P.

1989-01-01

205

Coupling of a scanning flow cell with online electrochemical mass spectrometry for screening of reaction selectivity.  

PubMed

In this work the online coupling of a miniaturized electrochemical scanning flow cell (SFC) to a mass spectrometer is introduced. The system is designed for the determination of reaction products in dependence of the applied potential and/or current regime as well as fast and automated change of the sample. The reaction products evaporate through a hydrophobic PTFE membrane into a small vacuum probe, which is positioned only 50-100 ?m away from the electrode surface. The probe is implemented into the SFC and directly connected to the mass spectrometer. This unique configuration enables fast parameter screening for complex electrochemical reactions, including investigation of operation conditions, composition of electrolyte, and material composition. The technical developments of the system are validated by initial measurements of hydrogen evolution during water electrolysis and electrochemical reduction of CO2 to various products, showcasing the high potential for systematic combinatorial screening by this approach. PMID:25362419

Grote, Jan-Philipp; Zeradjanin, Aleksandar R; Cherevko, Serhiy; Mayrhofer, Karl J J

2014-10-01

206

Coupling of a scanning flow cell with online electrochemical mass spectrometry for screening of reaction selectivity  

NASA Astrophysics Data System (ADS)

In this work the online coupling of a miniaturized electrochemical scanning flow cell (SFC) to a mass spectrometer is introduced. The system is designed for the determination of reaction products in dependence of the applied potential and/or current regime as well as fast and automated change of the sample. The reaction products evaporate through a hydrophobic PTFE membrane into a small vacuum probe, which is positioned only 50-100 ?m away from the electrode surface. The probe is implemented into the SFC and directly connected to the mass spectrometer. This unique configuration enables fast parameter screening for complex electrochemical reactions, including investigation of operation conditions, composition of electrolyte, and material composition. The technical developments of the system are validated by initial measurements of hydrogen evolution during water electrolysis and electrochemical reduction of CO2 to various products, showcasing the high potential for systematic combinatorial screening by this approach.

Grote, Jan-Philipp; Zeradjanin, Aleksandar R.; Cherevko, Serhiy; Mayrhofer, Karl J. J.

2014-10-01

207

Quantitative Label-Free Cell Proliferation Tracking with a Versatile Electrochemical Impedance Detection Platform  

NASA Astrophysics Data System (ADS)

Since the use of impedance measurements for label-free monitoring of cells has become widespread but still the choice of sensing configuration is not unique though crucial for a quantitative interpretation of data, we demonstrate the application of a novel custom multipotentiostat platform to study optimal detection strategies. Electrochemical Impedance Spectroscopy (EIS) has been used to monitor and compare adhesion of different cell lines. HeLa cells and 3T3 fibroblasts have been cultured for 12 hours on interdigitated electrode arrays integrated into a tailor-made cell culture platform. Both vertical and coplanar interdigitated sensing configuration approaches have been used and compared on the same cell populations.

Caviglia, C.; Carminati, M.; Heiskanen, A.; Vergani, M.; Ferrari, G.; Sampietro, M.; Andresen, T. L.; Emnéus, J.

2012-12-01

208

Electrical and Electrochemical Performance Characteristics of Large Capacity Li-Ion Cells  

SciTech Connect

We are currently evaluating large capacity (20 - 40 Ah) Bluestar (cylindrical) and Yardney (prismatic) Li-ion cells for their electrical and electrochemical performance characteristics at different temperatures. The cell resistance was nearly constant from room temperature to -20{degrees}C but increased by over 10 times at -40{degrees}C. The specific energy and power as well as the energy density and power density are high and didn't reach a plateau even at the highest discharge rates tested. For example, the prismatic Li-ion cells gave close to 280 Wh l{sup -1} at 4-amp discharge and 249 Wh l{sup -1} at 20-amp discharge at room temperature. For the same current range the specific power values are 102 Wh kg{sup -1} and 91 Wh kg{sup -1}. Cycle life and other electrical and electrochemical properties of the cells will be presented.

Doughty, I.D.; Hill, C.; Ingersoll, D.; Marsh, C.; Nagasubramanian, G.; Radzykewycz, D

1998-12-01

209

Elementary reaction modeling of solid oxide electrolysis cells: Main zones for heterogeneous chemical/electrochemical reactions  

NASA Astrophysics Data System (ADS)

A theoretical model of solid oxide electrolysis cells considering the heterogeneous elementary reactions, electrochemical reactions and the transport process of mass and charge is applied to study the relative performance of H2O electrolysis, CO2 electrolysis and CO2/H2O co-electrolysis and the competitive behavior of heterogeneous chemical and electrochemical reactions. In cathode, heterogeneous chemical reactions exist near the outside surface and the electrochemical reactions occur near the electrolyte. According to the mathematical analysis, the mass transfer flux D ?c determines the main zone size of heterogeneous chemical reactions, while the charge transfer flux ? ?V determines the other one. When the zone size of heterogeneous chemistry is enlarged, more CO2 could react through heterogeneous chemical pathway, and polarization curves of CO2/H2O co-electrolysis could be prone to H2O electrolysis. Meanwhile, when the zone size of electrochemistry is enlarged, more CO2 could react through electrochemical pathway, and polarization curves of CO2/H2O co-electrolysis could be prone to CO2 electrolysis. The relative polarization curves, the ratio of CO2 participating in electrolysis and heterogeneous chemical reactions, the mass and charge transfer flux and heterogeneous chemical/electrochemical reaction main zones are simulated to study the effects of cathode material characteristics (porosity, particle diameter and ionic conductivity) and operating conditions (gas composition and temperature).

Li, Wenying; Shi, Yixiang; Luo, Yu; Cai, Ningsheng

2015-01-01

210

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

NASA Astrophysics Data System (ADS)

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.

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

2011-03-01

211

Nanoarchitectured electrochemical cytosensors for selective detection of leukemia cells and quantitative evaluation of death receptor expression on cell surfaces.  

PubMed

The variable susceptibility to the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) treatment observed in various types of leukemia cells is related to the difference in the expression levels of death receptors, DR4 and DR5, on the cell surfaces. Quantifying the DR4/DR5 expression status on leukemia cell surfaces is of vital importance to the development of diagnostic tools to guide death receptor-based leukemia treatment. Taking the full advantages of novel nanobiotechnology, we have developed a robust electrochemical cytosensing approach toward ultrasensitive detection of leukemia cells with detection limit as low as ~40 cells and quantitative evaluation of DR4/DR5 expression on leukemia cell surfaces. The optimization of electron transfer and cell capture processes at specifically tailored nanobiointerfaces and the incorporation of multiple functions into rationally designed nanoprobes provide unique opportunities of integrating high specificity and signal amplification on one electrochemical cytosensor. The high sensitivity and selectivity of this electrochemical cytosensing approach also allows us to evaluate the dynamic alteration of DR4/DR5 expression on the surfaces of living cells in response to drug treatments. Using the TRAIL-resistant HL-60 cells and TRAIL-sensitive Jurkat cells as model cells, we have further verified that the TRAIL susceptibility of various types of leukemia cells is directly correlated to the surface expression levels of DR4/DR5. This versatile electrochemical cytosensing platform is believed to be of great clinical value for the early diagnosis of human leukemia and the evaluation of therapeutic effects on leukemia patients after radiation therapy or drug treatment. PMID:23621478

Zheng, Tingting; Fu, Jia-Ju; Hu, Lihui; Qiu, Fan; Hu, Minjin; Zhu, Jun-Jie; Hua, Zi-Chun; Wang, Hui

2013-06-01

212

Three-dimensional analysis of transport and electrochemical reactions in polymer electrolyte fuel cells  

Microsoft Academic Search

A computational fuel cell dynamics (CFCD) model is presented to elucidate three-dimensional (3D) interactions between mass transport and electrochemical kinetics in polymer electrolyte fuel cells with straight and interdigitated flowfields, respectively. The model features a detailed membrane–electrode assembly (MEA) submodel in which water transport through the membrane with spatially variable transport properties and spatial variations of the reaction rate and

Sukkee Um; C. Y. Wang

2004-01-01

213

Nano-Bio Electrochemical Interfacing–Linking Cell Biology and MicroElectronics  

Microsoft Academic Search

\\u000a Integration of biological substance within electronic devices is an innovative and challenging area combining recent progress\\u000a in molecular biology and micro technology. First, we introduce the concept of integrating living cells with Micro Electro\\u000a Mechanical Systems (MEMS). Following a brief overview on “whole cell based biosensors” we describe the design, fabrication,\\u000a and process of a biocompatible electrochemical “Lab-on-a-Chip” system. Demonstrating

Y. Shacham-Diamand; R. Popovtzer; Y. Rishpon

2010-01-01

214

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

E-print Network

Time-course correlation of biofilm properties and electrochemical performance in single-chamber microbial fuel cells Zhiyong Ren a,c , Ramaraja P. Ramasamy b,1 , Susan Red Cloud-Owen b , Hengjing Yan that the anode electrochemical polarization resistance can constrain system performance in both two-chamber

Mench, Matthew M.

215

Electrochemical Encyclopedia  

NSDL National Science Digital Library

This site contains a compendium of 44 articles in electrochemistry. The articles cover a number of different topics including electrochemical capacitors, the electrochemistry of plant life, solid oxide fuel cells and electrolytic capacitors.

216

Electrochemical circuit model of a PEM fuel cell  

Microsoft Academic Search

A dynamic circuit model for a fuel cell is presented. The model accounts for flow transients, the reactant partial pressures, as well as loss mechanisms within the fuel cell. For a selected PEM fuel cell design, analyses are performed to examine load transients imposed on the fuel cell. The PSpice programming environment was employed. Such model capability is required to

P. Famouri; Randall S. Gemmen

2003-01-01

217

Method of making an electrolyte for an electrochemical cell  

DOEpatents

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.

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

1996-01-01

218

Method of making an electrolyte for an electrochemical cell  

DOEpatents

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.

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

1996-04-30

219

Concurrent primary and secondary myiasis on basal cell carcinoma.  

PubMed

Myiasis is a disease caused by infestation of fly larvae in human and other vertebrate tissues. It is a skin condition common in tropical and subtropical countries and its predisposing factors are: chronic diseases, immunodeficiency, poor hygiene, senility, psychiatric disorders, skin cancers and ulcerated mucosae. We report the case of a healthy patient who after traumatic injury of a preexisting lesion showed a tumor on the dorsal region parasitized by fly larvae. The histopathological examination performed for the diagnosis of skin neoplasm surprisingly revealed the presence of a partially degenerated larva with characteristics of Dermatobia hominis, suggesting an association of primary and secondary myiasis on basal cell carcinoma. PMID:22570036

Raposo, Adriana Andrade; Schettini, Antônio Pedro Mendes; Massone, Cesare

2012-01-01

220

Electroporation followed by electrochemical measurement of quantal transmitter release from single cells using a patterned microelectrode  

PubMed Central

An electrochemical microelectrode located immediately adjacent to a single neuroendocrine cell can record spikes of amperometric current that result from exocytosis of oxidizable transmitter from individual vesicles, i.e., quantal exocytosis. Here, we report the development of an efficient method where the same electrochemical microelectrode is used to electropermeabilize an adjacent chromaffin cell and then measure the consequent quantal catecholamine release using amperometry. Trains of voltage pulses, 5–7 V in amplitude and 0.1–0.2 ms in duration, were used to reliably trigger release from cells using gold electrodes. Amperometric spikes induced by electropermeabilization had similar areas, peak heights and durations as amperometric spikes elicited by depolarizing high K+ solutions, therefore release occurs from individual secretory granules. Uptake of trypan blue stain into cells demonstrated that the plasma membrane is permeabilized by the voltage stimulus. Voltage pulses did not degrade the electrochemical sensitivity of the electrodes assayed using a test analyte. Surprisingly, robust quantal release was elicited upon electroporation in the absence of Ca2+ in the bath solution (0 Ca2+/5 mM EGTA). In contrast, electropermeabilization-induced transmitter release required Cl? in the bath solution in that bracketed experiments demonstrated a steep dependence of the rate of electropermeabilization-induced transmitter release on [Cl?] between 2 and 32 mM. Using the same electrochemical electrode to electroporate and record quantal release of catecholamines from an individual chromaffin cell allows precise timing of the stimulus, stimulation of a single cell at a time, and can be used to load membrane-impermeant substances into a cell. PMID:23598689

Ghosh, Jaya; Liu, Xin; Gillis, Kevin D.

2013-01-01

221

Current Collection Through The Ends Of A Spirally Wound Electrochemical Cell  

DOEpatents

An electrochemical cell, including a jelly-roll type electrode stack, and a method for making such cell. The electrochemical cell includes folded electrode portions which form a plane recessed from the end of the electrode stack. The folded electrode portions are preferably formed by making pairs of slits in the electrode end and bending over the electrode portions between each pair of slits. The recessed plane forms a large area to which a current collection tab is subsequently connected. A coating may be applied to the folded portions of the electrode to further increase the contact area with the current collection tab by eliminating the slight variations in the recessed plane which are due to the overlap of the folded electrode portions.

Oweis, Salah (Ellicott City, MD); Chagnon, Guy (Columbia, MD); Alunans, Peter (Baltimore, MD); Romero, Antonio (Parkton, MD)

1999-10-26

222

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

PubMed Central

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

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

2013-01-01

223

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

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

224

Anodes - Materials for negative electrodes in electrochemical energy technology  

NASA Astrophysics Data System (ADS)

The basic concepts of electrodes and electrochemical cells (including both galvanic and electrolytic ones) are introduced and illustrated with practical examples. Particular attention is paid to negative electrodes in primary and secondary cells, fuel cell electrodes and electrodes in redox flow batteries. General features and arguments pertaining to selection, optimization and further development are highlighted.

Holze, Rudolf

2014-06-01

225

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

DOEpatents

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.

Reichner, P.; Dollard, W.J.

1991-01-08

226

Synthesis of cobalt oxide-reduced graphene nanocomposite and its enhanced electrochemical properties as negative material for alkaline secondary battery  

NASA Astrophysics Data System (ADS)

A potential negative electrode material Co3O4@rGO is synthesized via a facile reflux condensation route. The electrochemical performances of Co3O4@rGO composite for alkaline rechargeable Ni/Co batteries have been systemically investigated for the first time. The reduced-graphene can remarkably enhance the electrochemical activity of Co3O4 materials, leading to a notable improvement of discharge capacity, cycle stability and rate capability. Interestingly, the maximum discharge capacity of Co3O4@rGO-20 (additive amount of GO is 20 mg) electrode can reach 511.4 mAh g-1 with the capacity retention of 89.1% after 100 cycles at a discharge current of 100 mA g-1. A properly electrochemical reaction mechanism of Co3O4@rGO electrode is also constructed in detail.

Xu, Yanan; Wang, Xiaofeng; An, Cuihua; Wang, Yijing; Jiao, Lifang; Yuan, Huatang

2014-12-01

227

BMP7 Expression Correlates with Secondary Drug Resistance in Mantle Cell Lymphoma  

E-print Network

of cell line. Incubation of BMP7 with MCL cell lines increased their resistance to bortezomibBMP7 Expression Correlates with Secondary Drug Resistance in Mantle Cell Lymphoma Valérie Camara to identify genes involved in secondary drug resistance in mantle cell lymphomas (MCL). Experimental Design

Boyer, Edmond

228

Dendritic cell subsets in primary and secondary T cell responses at body surfaces  

Microsoft Academic Search

We examine the role of dendritic cells subsets in immunity to peripheral infections, with emphasis on the differences in the regulation of primary and secondary T cell responses to viruses. Our major focus is on new developments in the understanding of immunity to infections of the skin and lung, which are crucial entry points for a variety of infectious pathogens.

William R Heath; Francis R Carbone

2009-01-01

229

Gene expression and metabolite profiles of cotton fiber during cell elongation and secondary cell wall synthesis  

Microsoft Academic Search

Cotton fibers elongate rapidly after initiation of elongation, eventually leading to the deposit of a large amount of cellulose. To reveal features of cotton fiber cells at the fast elongation and the secondary cell wall synthesis stages, we compared the respective transcriptomes and metabolite profiles. Comparative analysis of transcriptomes by cDNA array identified 633 genes that were differentially regulated during

Jin-Ying Gou; Ling-Jian Wang; Shuang-Ping Chen; Wen-Li Hu; Xiao-Ya Chen

2007-01-01

230

Cell-adhesive and cell-repulsive zwitterionic oligopeptides for micropatterning and rapid electrochemical detachment of cells.  

PubMed

In this study, we describe the development of oligopeptide-modified cell culture surfaces from which adherent cells can be rapidly detached by application of an electrical stimulus. An oligopeptide, CGGGKEKEKEK, was designed with a terminal cysteine residue to mediate binding to a gold surface via a gold-thiolate bond. The peptide forms a self-assembled monolayer through the electrostatic force between the sequence of alternating charged glutamic acid (E) and lysine (K) residues. The dense and electrically neutral oligopeptide zwitterionic layer of the modified surface was resistant to nonspecific adsorption of proteins and adhesion of cells, while the surface was altered to cell adhesive by the addition of a second oligopeptide (CGGGKEKEKEKGRGDSP) containing the RGD cell adhesion motif. Application of a negative electrical potential to this gold surface cleaved the gold-thiolate bond, leading to desorption of the oligopeptide layer, and rapid (within 2?min) detachment of virtually all cells. This approach was applicable not only to detachment of cell sheets but also for transfer of cell micropatterns to a hydrogel. This electrochemical approach of cell detachment may be a useful tool for tissue-engineering applications. PMID:22853640

Kakegawa, Takahiro; Mochizuki, Naoto; Sadr, Nasser; Suzuki, Hiroaki; Fukuda, Junji

2013-01-01

231

Cell-Adhesive and Cell-Repulsive Zwitterionic Oligopeptides for Micropatterning and Rapid Electrochemical Detachment of Cells  

PubMed Central

In this study, we describe the development of oligopeptide-modified cell culture surfaces from which adherent cells can be rapidly detached by application of an electrical stimulus. An oligopeptide, CGGGKEKEKEK, was designed with a terminal cysteine residue to mediate binding to a gold surface via a gold–thiolate bond. The peptide forms a self-assembled monolayer through the electrostatic force between the sequence of alternating charged glutamic acid (E) and lysine (K) residues. The dense and electrically neutral oligopeptide zwitterionic layer of the modified surface was resistant to nonspecific adsorption of proteins and adhesion of cells, while the surface was altered to cell adhesive by the addition of a second oligopeptide (CGGGKEKEKEKGRGDSP) containing the RGD cell adhesion motif. Application of a negative electrical potential to this gold surface cleaved the gold–thiolate bond, leading to desorption of the oligopeptide layer, and rapid (within 2?min) detachment of virtually all cells. This approach was applicable not only to detachment of cell sheets but also for transfer of cell micropatterns to a hydrogel. This electrochemical approach of cell detachment may be a useful tool for tissue-engineering applications. PMID:22853640

Kakegawa, Takahiro; Mochizuki, Naoto; Sadr, Nasser; Suzuki, Hiroaki

2013-01-01

232

Electrochemical Oscillations of Nickel Electrodissolution in an Epoxy-Based Microchip Flow Cell  

PubMed Central

We investigate the nonlinear dynamics of transpassive electrodissolution of nickel in sulfuric acid in an epoxy-based microchip flow cell. We observed bistability, smooth, relaxation, and period-2 waveform current oscillations with external resistance attached to the electrode in the microfabricated electrochemical cell with 0.05 mm diameter Ni wire under potentiostatic control. Experiments with 1mm × 0.1 mm Ni electrode show spontaneous oscillations without attached external resistance; similar surface area electrode in macrocell does not exhibit spontaneous oscillations. Combined experimental and numerical studies show that spontaneous oscillation with the on-chip fabricated electrochemical cell occurs because of the unusually large ohmic potential drop due to the constrained current in the narrow flow channel. This large IR potential drop is expected to have an important role in destabilizing negative differential resistance electrochemical (e.g., metal dissolution and electrocatalytic) systems in on-chip integrated microfludic flow cells. The proposed experimental setup can be extendend to multi-electrode configurations; the epoxy-based substrate procedure thus holds promise in electroanalytical applications that require collector-generator multi-electrodes wires with various electrode sizes, compositions, and spacings as well as controlled flow conditions. PMID:21822407

Cioffi, Alexander G.; Martin, R. Scott; Kiss, István Z.

2011-01-01

233

System and method for charging electrochemical cells in series  

DOEpatents

A battery charging system capable of equalizing the charge of each individual cell at a selected full charge voltage includes means for regulating charger current to first increase current at a constant rate until a bulk charging level is achieved or until any cell reaches a safe reference voltage. A system controller then begins to decrease the charging rate as long as any cell exceeds the reference voltage until an equalization current level is reached. At this point, the system controller activates a plurality of shunt modules to permit shunting of current around any cell having a voltage exceeding the reference voltage. Leads extending between the battery of cells and shunt modules are time shared to permit alternate shunting of current and voltage monitoring without the voltage drop caused by the shunt current. After each cell has at one time exceeded the reference voltage, the charging current is terminated.

DeLuca, William H. (Naperville, IL); Hornstra, Jr, Fred (St. Charles, IL); Gelb, George H. (Rancho Palos Verdes, CA); Berman, Baruch (Rancho Palos Verdes, CA); Moede, Larry W. (Manhattan Beach, CA)

1980-01-01

234

Development of a bipolar cell for electrochemical production of lithium  

SciTech Connect

Lithium metal can be electrolytically refined from aqueous solutions of its compounds by partial reduction to form a lithium amalgam, followed by reduction of the amalgam to liquid lithium in a molten salt cell at 225 C. A bipolar cell (with a continuous, amalgam electrode circulating between the aqueous and salt cells) was designed, constructed and successfully tested on the bench scale, as a proof of principle of an efficient, safe and low-temperature alternative to existing processes.

Cooper, J.F.; Mack, G.; Peterman, K.; Weinland, S. [Lawrence Livermore National Lab., CA (United States); McKenzie, P. [Martin Marietta Energy Systems, Inc., Oak Ridge, TN (United States)

1995-02-22

235

Multi-gas transportation and electrochemical performance of a polymer electrolyte fuel cell with complex flow channels  

Microsoft Academic Search

A three-dimensional (3D) numerical model associating the heat\\/mass transfer and the electrochemical reaction in a proton exchange membrane (PEM) fuel cell is developed in this study, and a miniaturized PEM fuel cell with complex flow channels is simulated. The numerical computation is based on the finite-volume method. Governing equations for flow and heat\\/mass transfer are coupled with the electrochemical reactions

Pei-Wen Li; Laura Schaefer; Qing-Ming Wang; Tao Zhang; Minking K. Chyu

2003-01-01

236

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

SciTech Connect

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.

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

1995-09-01

237

Fuel cell efficiency in a combined electrochemical-thermochemical process  

Microsoft Academic Search

The thermodynamics of an H2\\/Cl2 fuel cell combined with a thermochemical hydrogen chloride oxidation stage are considered. Such a cycle is superior to the phosphoric acid H2\\/O2 systems but does not better the efficiency demonstrated in more advanced H2\\/O2 fuel cell systems.

E. N. Balko; W. Avery

1981-01-01

238

Electrochemical and microstructural characterization of the redox tolerance of solid oxide fuel cell anodes  

NASA Astrophysics Data System (ADS)

The most commonly used solid oxide fuel cell (SOFC) anode material is a two phase nickel and yttria stabilized zirconia (Ni/YSZ) cermet. During typical fuel cell operation, this material remains a cermet; however, the anode may reoxidize in a commercial SOFC system due to seal leakage, fuel supply interruption, or system shutdown. The cyclic reduction and oxidation (redox) of nickel will result in large bulk volume changes, which may have a significant effect on the integrity of interfaces within the fuel cell and thus may cause significant performance degradation. A baseline of the redox behaviour of an anode-supported SOFC was developed using electrochemical testing and electron microscopy. During redox tests, the cell's initial performance was characterized and then a small amount of air was blown over the anode in order to reoxidize the cell. The cell was then reduced and the electrochemical performance was remeasured in order to determine the amount of redox degradation. Cell performance decreased slightly after each redox cycle, especially for redox times greater than 1 hour. The microstructural changes that occurred after redox cycling were characterized using scanning and transmission electron microscopy (SEM and TEM). Redox cycling significantly changed the microstructure of the anode substrate in the cell.

Waldbillig, D.; Wood, A.; Ivey, D. G.

239

Analysis of Electrochemical and Thermal Behavior of Li-Ion Cells  

Microsoft Academic Search

This paper seeks to gain a better understanding of the thermal behavior of Li-ion cells using a previously developed two- dimensional, first principles-based thermal-electrochemical modeling approach. The model incorporates the reversible, irrevers- ible, and ohmic heats in the matrix and solution phases, and the temperature dependence of the various transport, kinetic, and mass-transfer parameters based on Arrhenius expressions. Experimental data

Venkat Srinivasan; C. Y. Wang

2003-01-01

240

Zinc--halogen compound electrochemical cell having an auxiliary electrode and method. [to prevent Hâ buildup  

Microsoft Academic Search

An electrochemical cell is described which contains, in a sealed configuration, an anode having a zinc anode-active material, a cathode having a halogen compound cathode-active material, a liquid electrolyte having a gas space above it, and an auxiliary electrode. The auxiliary electrode is made of a carbon-containing hydrophobic material, is adapted to carry a cathodic potential, and is positioned in

Kantner

1978-01-01

241

Characterisation of proton exchange membrane fuel cell (PEMFC) failures via electrochemical impedance spectroscopy  

Microsoft Academic Search

Two PEMFC failure modes (dehydration and flooding) were investigated using in situ electrochemical impedance spectroscopy (EIS) on a four-cell stack under load. The EIS measurements were made at different temperatures (70 and 80°C), covering the current density range 0.1–1.0Acm?2, and the frequency range 0.1–2×105Hz. Dehydration and flooding effects were observed in the frequency ranges 0.5–105 and 0.5–102Hz, respectively.We propose that

W. Mérida; D. A. Harrington; J. M. Le Canut; G. McLean

2006-01-01

242

Development and electrochemical studies of gas diffusion electrodes for polymer electrolyte fuel cells  

Microsoft Academic Search

Electrochemical studies on low catalyst loading gas diffusion electrodes for polymer electrolyte fuel cells are reported. The best performance is obtained with an electrode formed from 20 wt% Pt\\/C, 0.4 mg Pt cm-2 and 1.1 mg Nafion® cm-2 in the catalyst layer and 15% PTFE in a diffusion layer of 50 µm thickness, for both the cathode and the anode.

V. A. Paganin; E. A. Ticianelli; E. R. Gonzalez

1996-01-01

243

Kinetic model of cell growth and secondary metabolite synthesis in plant cell culture of Thalictrum rugosum  

Microsoft Academic Search

A structured kinetic model was proposed to describe cell growth and synthesis of a secondary metabolite, berberine, in batch\\u000a suspension culture ofThalictrum rugosum. The model was developed by representing the physiological state of the cell in terms of the activity and the viability,\\u000a which can be estimated using the culture fluorescence measurement. In the proposed model, the cells were divided

Jeong-Woo Choi; Young-Kee Kim; Won Hong Lee; Henrik Pedersen; Chee-Kok Chin

1999-01-01

244

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

NASA Technical Reports Server (NTRS)

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.

Thornton, D. C.; Niazy, N.

1982-01-01

245

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

NASA Astrophysics Data System (ADS)

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.

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

2009-11-01

246

Electronic circuit for measuring series connected electrochemical cell voltages  

DOEpatents

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.

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

2000-01-01

247

Potassium Beta-Alumina/Molybdenum/Potassium Electrochemical Cells  

NASA Technical Reports Server (NTRS)

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.

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

1994-01-01

248

Space Electrochemical Research and Technology  

NASA Technical Reports Server (NTRS)

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.

1993-01-01

249

Novel duplex vapor-electrochemical method for silicon solar cells  

NASA Technical Reports Server (NTRS)

A process was developed for the economic production of high purity Si from inexpensive reactants, based on the Na reduction of SiF4 gas. The products of reaction (NaF, Si) are separated by either aqueous leaching or by direct melting of the NaF-Si product mixture. Impurities known to degrade solar cell performance are all present at sufficiently low concentrations so that melt solidification (e.g., Czochralski) will provide a silicon material suitable for solar cells.

Nanis, L.; Sanjurjo, A.; Sancier, K. M.; Kapur, V. K.; Bartlett, R. W.; Westphal, S.

1980-01-01

250

Mechanisms for shaping, orienting, positioning and patterning plant secondary cell walls  

PubMed Central

Xylem vessels are cells that develop a specifically ornamented secondary cell wall to ensure their vascular function, conferring both structural strength and impermeability. Further plasticity is given to these vascular cells by a range of different patterns described by their secondary cell walls that—as for the growth of all plant organs—are developmentally regulated. Microtubules and their associated proteins, named MAPs, are essential to define the shape, the orientation, the position and the overall pattern of these secondary cell walls. Key actors in this process are the land-plant specific MAP70 proteins which not only allow the secondary cell wall to be positioned at the cell cortex but also determine the overall pattern described by xylem vessel secondary cell walls. PMID:21558816

Korolev, Andrey V; Calder, Grant; Lloyd, Clive W

2011-01-01

251

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

PubMed Central

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

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

2013-01-01

252

Influence of compressible aerogel electrodes on the properties of an electrochemical cell  

NASA Astrophysics Data System (ADS)

In the biomedical field the need for intra organ pressure measurement can only be facilitated by adapting existing pressure sensing technology to the specific tissues under test. The customization of these sensors has only driven up cost and the need to explore new technologies has become increasingly more important. For this dissertation, we explore the use of a new technology, particularly electrochemical pressure sensing to provide a low-cost pressure sensor to fill this need. Preliminary testing showed that electrically conductive polymers exhibited a change in voltage when pressurized if bubbles were first electrolyzed in the gel creating an aerogel, and that this effect was virtually undetectable without the bubbles present. Using electrochemical impedance spectroscopy (EIS) and model fitting, it was shown that this effect occurs at the electrode interface. Theoretical derivation supported by potentiostatic voltage measurements indicated that a change in the electrode surface area in contact with the fluid was responsible for the effect. Optical micrographs were taken as a bubble along the electrode was pressurized. Using image analysis, the relationship of the change in surface area of the bubble correlated to the relationship of the change in impedance of the electrochemical cell (ECC). The results further demonstrated that the electrochemical response to pressure of a gelatin aerogel electrode was linear for the pressure range of 0 to1034 mmHg. This finding lends itself well for use in medical devices. A new device was invented along with a manufacturing process for an electrochemical pressure transducer (EPT). The EPT was subject to in vitro testing using simulated gastric fluid to create a baseline efficacy of the device for use in the gastrointestinal tract. Multiple design specific techniques were developed to improve sensor performance during physiological conditions.

Sponheimer, Christopher

253

Microfluidic electrochemical reactors  

DOEpatents

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.

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

2011-03-22

254

Effects of synthesis temperature on the electrochemical characteristics of pyrolytic carbon for anodes of lithium-ion secondary batteries  

Microsoft Academic Search

The electrochemical properties of new disordered carbon materials obtained by a gas-phase reaction of LPG (liquid propane gas) have been studied. Pyrolysis of LPG was performed in the temperature range 900 to 1,200 C. The lithium storage mechanism in these disordered carbons has been investigated by the charge-discharge tester, cyclic voltammeter, X-ray diffraction (XRD), solid-state ⁷Li nuclear magnetic resonance (NMR),

Young-Soo Han; J. S. Yu; G. S. Park; J. Y. Lee

1999-01-01

255

Low-hazard metallography of moisture-sensitive electrochemical cells.  

PubMed

A low-hazard approach is presented to prepare metallographic cross-sections of moisture-sensitive battery components. The approach is tailored for evaluation of thermal (molten salt) batteries composed of thin pressed-powder pellets, but has general applicability to other battery electrochemistries. Solution-cast polystyrene is used to encapsulate cells before embedding in epoxy. Nonaqueous grinding and polishing are performed in an industrial dry room to increase throughput. Lapping oil is used as a lubricant throughout grinding. Hexane is used as the solvent throughout processing; occupational exposure levels are well below the limits. Light optical and scanning electron microscopy on cross-sections are used to analyse a thermal battery cell. Spatially resolved X-ray diffraction on oblique angle cut cells complement the metallographic analysis. PMID:21477264

Wesolowski, D E; Rodriguez, M A; McKenzie, B B; Papenguth, H W

2011-08-01

256

Process for manufacturing a lithium alloy electrochemical cell  

DOEpatents

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.

Bennett, William R. (North Olmstead, OH)

1992-10-13

257

Effect of the length and surface area on electrochemical performance of cobalt oxide nanowires for alkaline secondary battery application  

NASA Astrophysics Data System (ADS)

One-dimensional porous Co3O4 nanowires with different length have been successfully synthesized by thermal decomposition of Co-NA polymer precursors at various hydrothermal reaction times. The positive effects of longer nanowires and larger surface area on electrochemical performance of Co3O4 samples were investigated systematically. All the as-prepared Co3O4 samples display excellent discharge capacities and cycle stability on account of large surface area and porous structure, indicating great potential application of porous Co3O4 nanowires for alkaline rechargeable batteries. The Co3O4-24 h sample with the longest length shows the most outstanding electrochemical performance, and displays the maximum discharge capacity of 450.1 mAh g-1 with the capacity retention of 90.4% after 100 cycles at a current density of 100 mA g-1. Electrochemical reactions between Co and Co(OH)2 occurring on the Co3O4 electrodes are investigated by XRD, cyclic voltammetry (CV) and charge-discharge measurements.

Xu, Yanan; Wang, Xiaofeng; An, Cuihua; Wang, Yijing; Jiao, Lifang; Yuan, Huatang

2014-12-01

258

Electrochemical behavior of CIGS electrodeposition for applications to photovoltaic cells  

NASA Astrophysics Data System (ADS)

The electrodeposition mechanism of Cu(In,Ga)Se2 (CIGS) thin films on ITO substrates was examined by using cyclic voltammetry (CV). The CV study was performed in unitary In, binary In-Se, ternary Cu-In-Se, and quaternary Cu-In-Ga-Se systems. CV of the Cu-In-Ga-Se system revealed a reduction peak at -0.6 V with the addition of GaCl3 and showed that the current density was affected significantly by the concentrations of GaCl3 and InCl3. This is probably due to the adsorption-site competition between In3+ and Ga3+ on the electrode surface. Energy dispersive X-ray spectroscopy confirmed the CV results. The composition of Ga in the CIGS films increased with increasing concentration of GaCl3 in the electrolyte whereas the composition of In decreased sharply. The as-deposited films were annealed at 500 °C in a N2 atmosphere for crystallization. XRD revealed three major peaks corresponding to the (112), (220) and (312) planes of CIGS chalcopyrite respectively. On the other hand, a secondary phase, such as In4Se3, was observed in the CIGS films containing a high In composition.

Lee, Hyunju; Ji, Changwook; Kim, Yangdo; Lee, Jae-Ho; Hwang, Yoon-Hwae; Jo, Ilguk; Kim, Hyoungchan

2014-04-01

259

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

NASA Astrophysics Data System (ADS)

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.

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

2015-02-01

260

Direct In Vivo Electrochemical Detection of Haemoglobin in Red Blood Cells  

PubMed Central

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. PMID:25163492

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

2014-01-01

261

Direct in vivo electrochemical detection of haemoglobin in red blood cells.  

PubMed

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. PMID:25163492

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

2014-01-01

262

Direct In Vivo Electrochemical Detection of Haemoglobin in Red Blood Cells  

NASA Astrophysics Data System (ADS)

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.

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

2014-08-01

263

Biological applications of scanning electrochemical microscopy: chemical imaging of single living cells and beyond.  

PubMed

Recent applications of scanning electrochemical microscopy (SECM) to studies of single biological cells are reviewed. This scanning probe microscopic technique allows the imaging of an individual cell on the basis of not only its surface topography but also such cellular activities as photosynthesis, respiration, electron transfer, single vesicular exocytosis and membrane transport. The operational principles of SECM are also introduced in the context of these biological applications. Recent progress in techniques for high-resolution SECM imaging are also reviewed. Future directions, such as single-channel detection by SECM, high-resolution imaging with nanometer-sized probes, and combined SECM techniques for multidimensional imaging are also discussed. PMID:16855816

Amemiya, Shigeru; Guo, Jidong; Xiong, Hui; Gross, Darrick A

2006-10-01

264

Structure and function of an inorganic-organic separator for electrochemical cells: Preliminary study  

NASA Technical Reports Server (NTRS)

The structure of a new separator material for electrochemical cells has been investigated. Investigation into details of the separator structure showed it to be multilayered and to consist mainly of a quasi-impervious organic skin, a porous region of mixed organic and inorganic material, and an area of nonuniformly treated substrate. The essential feature of the coating (slurry) is believed to be interconnected pores which allow ionic conductivity. The interconnected pores are believed to be formed by the interaction of the plasticizer and inorganic fibers. The major failure mode of silver zinc cells using such a separator (zinc nodules shorting adjacent plates) was investigated.

Bozek, J. M.

1974-01-01

265

X-ray absorption and electrochemical studies of direct methanol fuel cell catalysts  

SciTech Connect

In order for polymer electrolyte fuel cells to operate directly on methanol instead of hydrogen, methanol oxidation must be catalyzed in the acidic cell environment. Pt-Ru and Pt-Ru oxide are considered to be the most active catalysts for this purpose; Ru enhances the Pt activity for reasons not yet fully understood. XAS and electrochemical techniques were used to study this enhancement. Preliminary results indicate that Ru does effect the d-band occupancy of Pt, which in turn may effect the kinetics of the methanol oxidation reaction on this metal by altering the strength of the Pt-CO bond. Further research is needed.

Zurawski, D.J.; Aldykiewicz, A.J. Jr.; Baxter, S.F.; Krumpelt, M.

1996-12-31

266

Electrochemical storage  

NASA Technical Reports Server (NTRS)

The source of the problem within the individual single cell which is related to the stochastic properties of cell populations and to the actual electrochemistry and chemistry taking place is described. The complications which arise in multicell batteries to show how different electrochemistries might alleviate or accentuate these problems is described. The concept of the electrochemical system is introduced to show how certain shortcomings of the single cell/battery string concept can be circumvented. Some of these electrochemical systems permit performance characteristics that are impossible by using conventional battery design philosophies. Projections for energy density and performance characteristics of the concepts are addressed.

Thaller, L. H.

1984-01-01

267

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

DOEpatents

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.

Shockling, L.A.

1991-09-10

268

An efficient nanomaterial-based electrochemical biosensor for sensitive recognition of drug-resistant leukemia cells.  

PubMed

A novel electrochemical cytosensor was developed for the fast and high-sensitivity recognition of drug-resistant leukemia K562/ADM cells based on the P-glycoprotein (P-gp) expression level on a cell membrane. The nanocomposite interface of the gold nanoparticles/polyaniline nanofibers (AuNPs/PANI-NF) was chosen to design the biosensor for electrochemical detection. Au/PANI-NF-based cytosensors coated with anti-P-glycoprotein (anti-P-gp) molecules could provide a biomimetic interface for the immunosensing of cell surface P-glycoprotein, and thus could capture the over-expression P-gp cells. Transmission electron microscopy (TEM) indicated that the gold nanoparticles were uniformly anchored along the structure of the PANI-NF surface, displaying fibrillar morphology with a diameter of ?70 nm, and atomic force microscopy (AFM) further presented the morphology of the nanocomposite film. Owing to the high affinity of anti-P-gp for leukemia K562/ADM cells of the propounded sensing platform, the proposed biosensor exhibited excellent analytical performance for leukemia K562/ADM cells, ranging from 1.6 × 10(2) to 1.6 × 10(6) cells per mL with a detection limit of 80 cells per mL. Recovery experiments indicated that the sensitivity reported here is suitable for practical application. The cell surface P-gp expression level was analysed by flow cytometric experiments, which confirmed the above recognized result. This strategy is also a cost-effective and convenient operation, implying great promise for the sensitive recognition of cancer cells and cell surface receptors; thus, it is helpful in cancer diagnosis. PMID:24889704

Zhang, Shaolian; Zhang, Lu; Zhang, Xi; Yang, Peihui; Cai, Jiye

2014-07-21

269

Life capability of the silver electrode in alkaline electrochemical cells  

NASA Technical Reports Server (NTRS)

Estimates of silver electrode degradation rates were made by comparing the recently measured capacities with the reported early life capacities. Chemical analyses were carried out to determine the extent of silver loss from the electrode and its distribution throughout the cell components. The results established that the silver electrode is very stable when stored at reduced temperatures in the range of 0 to -51 C, in which it exhibits a permanent degradation in capacity of 0.5%/year. The results also indicated that the silver electrode is not quite as stable when operated and stored at room temperature, where it exhibits permanent degradation in the range of 3% to 14%/year. These results were employed in predicting the life capability of the proposed new Ag-H2 cell and also in assessing the merits of employing silver electrodes in long-life probe batteries.

Frank, H. A.

1976-01-01

270

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

E-print Network

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 seParenchyma cell respiration and survival in secondary xylem: does metabolic activity decline

Holbrook, N. Michele

271

In-situ quantification of solid oxide fuel cell electrode microstructure by electrochemical impedance spectroscopy  

NASA Astrophysics Data System (ADS)

Three-dimensional (3D) microstructure of solid oxide fuel cell electrodes plays critical roles in determining fuel cell performance. The state-of-the-art quantification technique such as X-ray computed tomography enables direct calculation of geometric factors by 3D microstructure reconstruction. Taking advantages of in-situ, fast-responding and low cost, electrochemical impedance spectroscopy represented by distribution of relaxation time (DRT) is a novel technique to estimate geometric properties of fuel cell electrodes. In this study, we employed the anode supported cells with the cell configuration of Ni-YSZ || YSZ || LSM-YSZ as an example and compared the tortuosity factor of pores of the anode substrate layer by X-ray computed tomography and DRT analysis. Good agreement was found, validating the feasibility of in-situ microstructural quantification by using the DRT technique.

Zhang, Yanxiang; Chen, Yu; Chen, Fanglin

2015-03-01

272

Mixed solvent electrolytes for ambient temperature secondary lithium cells  

NASA Technical Reports Server (NTRS)

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.

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

1991-01-01

273

Electrical and Electrochemical Performance Characteristics of Small Commercial Li-Ion Cells  

SciTech Connect

Advanced rechargeable lithium-ion batteries are presently being developed and commercialized worldwide for use in consumer electronics, military and space applications. At Sandia National Laboratories we have used different electrochemical techniques such as impedance and charge/discharge at ambient and subambient temperatures to probe the various electrochemical processes that are occurring in Li-ion cell. The purpose of this study is to identify the component that reduces the cell performance at subambient temperatures. Our impedance data suggest that while the variation in the electrolyte resistance between room temperature and {minus}20 C is negligible the anode electrolyte interfacial resistance increases by an order of magnitude in the same temperature regime. We believe that the solid electrolyte interface (SEI) layer on the carbon anode may be responsible for the increase in cell impedance. We have also evaluated the cells in hybrid mode with capacitors. High-current operation in the hybrid mode allowed fill usage of the Li-ion cell capacity at 25 C and showed a factor of 5 improvement in delivered capacity at {minus}20 C.

Ingersoll, D.; Nagasubramanian, G.; Roth, E.P.

1998-12-22

274

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

NASA Astrophysics Data System (ADS)

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.

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

2013-03-01

275

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

SciTech Connect

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.

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

2011-11-01

276

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

ERIC Educational Resources Information Center

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…

Oztap, Haydar; Ozay, Esra; Oztap, Fulya

2003-01-01

277

Electrochemical monitoring of chlorhexidine digluconate effect on polyelectrolyte immobilized bacteria and kinetic cell adhesion.  

PubMed

The electrochemical impedance spectroscopy (EIS) technique has been used as a sensitive method to explore the effect of antibacterial molecules on immobilized bacteria and biofilm formation. In this work, we describe the electrochemical spectroscopy as a powerful method to monitor the effect of chlorhexidine digluconate (CHX-Dg) on polyelectrolyte immobilized Escherichia coli K12 MG1655 and the kinetics of cell adhesion on gold electrodes. The experimental impedance data were modeled with a Zview program to find the best equivalent electrical circuit and analyse its parameter's properties. Polyelectrolyte multilayer formation on the electrode surface and bacteria immobilization greatly increased the electron-transfer resistance (R(et)) and reduced the constant phase element (CPE(dl)). The effect of CHX-Dg was studied in a 0.5 x 10?? mmol l?¹ to 0.5 mmol l?¹ range. The relation between the evolution of R(et) and CHX-Dg concentration was found to be negatively correlated. When CHX-Dg was added, the electrochemical monitoring of the bacterial kinetic adhesion showed that the electrode's capacity (C(P)) variation remained stable, demonstrating that the addition of CHX-Dg in the broth inhibited bacterial adhesion. PMID:21112357

Borghol, N; Mora, L; Sakly, N; Lejeune, P; Jouenne, T; Jaffrézic-Renault, N; Othmane, A

2011-01-10

278

A whole-cell electrochemical biosensing system based on bacterial inward electron flow for fumarate quantification.  

PubMed

Fumarate is of great importance as it is an oncometabolite as well as food spoilage indicator. However, cost-effective and fast quantification method for fumarate is lacking although it is urgently required. This work developed an electrochemical whole-cell biosensing system for fumarate quantification. A sensitive inwards electric output (electron flow from electrode into bacteria) responded to fumarate in Shewanella oneidensis MR-1 was characterized, and an electrochemical fumarate biosensing system was developed without genetic engineering. The biosensing system delivered symmetric current peak immediately upon fumarate addition, where the peak area increased in proportion to the increasing fumarate concentration with a wide range of 2?M-10mM (R(2)=0.9997). The limit of detection (LOD) and the limit of quantification (LOQ) are 0.83?M and 1.2?M, respectively. This biosensing system displayed remarkable specificity to fumarate against other possible interferences. It was also successfully applied to samples of apple juice and kidney tissue. This study added new dimension to electrochemical biosensor design, and provide a simple, cost-effective, fast and robust tool for fumarate quantification. PMID:25558872

Si, Rong-Wei; Zhai, Dan-Dan; Liao, Zhi-Hong; Gao, Lu; Yong, Yang-Chun

2015-06-15

279

High-temperature "spectrochronopotentiometry": correlating electrochemical performance with in situ Raman spectroscopy in solid oxide fuel cells.  

PubMed

Carbon formation or "coking" on solid oxide fuel cell (SOFC) anodes adversely affects performance by blocking catalytic sites and reducing electrochemical activity. Quantifying these effects, however, often requires correlating changes in SOFC electrochemical efficiency measured during operation with results from ex situ measurements performed after the SOFC has been cooled and disassembled. Experiments presented in this work couple vibrational Raman spectroscopy with chronopotentiometry to observe directly the relationship between graphite deposited on nickel cermet anodes and the electrochemical performance of SOFCs operating at 725 °C. Raman spectra from Ni cermet anodes at open circuit voltage exposed to methane show a strong vibrational band at 1556 cm(-1) assigned to the "G" mode of highly ordered graphite. When polarized in the absence of a gas-phase fuel, these carbon-loaded anodes operate stably, oxidizing graphite to form CO and CO(2). Disappearance of graphite intensity measured in the Raman spectra is accompanied by a steep ?0.8 V rise in the cell potential needed to keep the SOFC operating under constant current conditions. Continued operation leads to spectroscopically observable Ni oxidation and another steep rise in cell potential. Time-dependent spectroscopic and electrochemical measurements pass through correlated equivalence points providing unequivocal, in situ evidence that identifies how SOFC performance depends on the chemical condition of its anode. Chronopotentiometric data are used to quantify the oxide flux necessary to eliminate the carbon initially present on the SOFC anode, and data show that the oxidation mechanisms responsible for graphite removal correlate directly with the electrochemical condition of the anode as evidenced by voltammetry and impedance measurements. Electrochemically oxidizing the Ni anode damages the SOFC significantly and irreversibly. Anodes that have been reconstituted following electrochemical oxidation of carbon and Ni show qualitatively different kinetics of carbon removal, and the electrochemical performance of these systems is characterized by low maximum currents and large polarization resistances. PMID:23046116

Kirtley, John D; Halat, David M; McIntyre, Melissa D; Eigenbrodt, Bryan C; Walker, Robert A

2012-11-20

280

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

NASA Astrophysics Data System (ADS)

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.

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

2014-08-01

281

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

PubMed Central

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. PMID:25124398

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

2014-01-01

282

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)

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.

Mori, Ryohei

2014-04-01

283

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

PubMed Central

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

Yi, C; Gratzl, M

1998-01-01

284

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

DOEpatents

An electrochemical apparatus (10) is made having a generator section (22) containing axially elongated electrochemical cells (16), a fresh gaseous feed fuel inlet (28), a gaseous feed oxidant inlet (30), and at least one gaseous spent fuel exit channel (46), where the spent fuel exit channel (46) passes from the generator chamber (22) to combine with the fresh feed fuel inlet (28) at a mixing apparatus (50), reformable fuel mixture channel (52) passes through the length of the generator chamber (22) and connects with the mixing apparatus (50), that channel containing entry ports (54) within the generator chamber (22), where the axis of the ports is transverse to the fuel electrode surfaces (18), where a catalytic reforming material is distributed near the reformable fuel mixture entry ports (54).

Reichner, Philip (Plum Borough, PA); Dollard, Walter J. (Churchill Borough, PA)

1991-01-01

285

Supporting electrodes for solid oxide fuel cells and other electrochemical devices  

DOEpatents

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.

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

2008-04-01

286

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

PubMed

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

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

2014-11-26

287

Hydrophilic Electrode For An Alkaline Electrochemical Cell, And Method Of Manufacture  

DOEpatents

A negative electrode for an alkaline electrochemical cell. The electrode comprises an active material and a hydrophilic agent constituted by small cylindrical rods of polyolefin provided with hydrophilic groups. The mean length of the rods is less than 50 microns and the mean diameter thereof is less than 20 microns. A method of manufacturing a negative electrode in which hydrophilic rods are made by fragmenting long polyolefin fibers having a mean diameter of less than 20 microns by oxidizing them, with the rods being mixed with the active material and the mixture being applied to a current conductor.

Senyarich, Stephane (Mornac, FR); Cocciantelli, Jean-Michel (Bordeaux, FR)

2000-03-07

288

Self-powered electrochemical memristor based on a biofuel cell--towards memristors integrated with biocomputing systems.  

PubMed

The electrochemical memristor based on a pH-switchable polymer-modified electrode integrated with a biofuel cell was designed and proposed for interfacing between biomolecular information processing and electronic systems. The present approach demonstrates a new application of biofuel cells in information processing systems, rather than for electrical power generation. PMID:24687004

MacVittie, Kevin; Katz, Evgeny

2014-05-14

289

A Multilayer MEMS Platform for Single-Cell Electric Impedance Spectroscopy and Electrochemical Analysis  

PubMed Central

The fabrication and characterization of a microchamber electrode array for electrical and electrochemical studies of individual biological cells are presented. The geometry was tailored specifically for measurements from sensory hair cells isolated from the cochlea of the mammalian inner ear. Conventional microelectromechanical system (MEMS) fabrication techniques were combined with a heat-sealing technique and polydimethylsiloxane micromolding to achieve a multilayered microfluidic system that facilitates cell manipulation and selection. The system allowed for electrical stimulation of individual living cells and interrogation of excitable cell membrane dielectric properties as a function of space and time. A three-electrode impedimetric system was incorporated to provide the additional ability to record the time-dependent concentrations of specific biochemicals in microdomain volumes near identified regions of the cell membrane. The design and fabrication of a robust fluidic and electrical interface are also described. The interface provided the flexibility and simplicity of a “cartridge-based” approach in connecting to the MEMS devices. Cytometric measurement capabilities were characterized by using electric impedance spectroscopy (1 kHz–10 MHz) of isolated outer hair cells. Chemical sensing capability within the microchannel recording chamber was characterized by using cyclic voltammetry with varying concentrations of potassium ferricyanide (K3Fe(CN)6). Chronoamperometric recordings of electrically stimulated PC12 cells highlight the ability of the platform to resolve exocytosis events from individual cells. PMID:19756255

Dittami, Gregory M.; Ayliffe, H. Edward; King, Curtis S.; Rabbitt, Richard D.

2008-01-01

290

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

PubMed Central

We report an electrochemical impedance microscope (EIM) based on surface plasmon resonance. The new EIM can resolve local impedance with sub-micron spatial resolution, and monitor dynamics of various processes, such as apoptosis and electroporation of individual cells with millisecond time resolution. The high spatial and temporal resolution images make it possible to not only study individual cells, but also resolve the sub-cellular structures and processes without labels. The detection sensitivity achieved with the current setup is ~2 pS, which is excellent considering the conductance of a single ion channel is in the range of 5–400 pS. We describe also a model that simulates the EIM images of cells based on local dielectric constant and conductivity. PMID:21336333

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

2012-01-01

291

The electrochemical performance of thin-electrolyte solid oxide fuel cells  

SciTech Connect

Several benefits are realized by lowering the operating temperature of solid oxide fuel cells (SOFCs) from 1000C to temperatures in the 600 to 800C range. Among the advantages are decreased reaction between fuel cell components, shorter startup times, and the possibility of using metals in stack construction; however, the achievable power density in conventional SOFCs is too low. A strategy for overcoming this limitation is to decrease the thickness of this layer by approximately an order of magnitude. Thin (5 {mu}m) electrolyte SOFCs have recently been fabricated by Allied-Signal Aerospace Systems and Equipment Company (ASASE). The electrochemical performance of these cells has been studied and is discussed in this paper.

Zurawski, D.; Kueper, T.

1993-09-01

292

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

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…

Cady, Susan G.

2014-01-01

293

Computational modeling of transport and electrochemical reactions in proton-exchange membrane fuel cells  

NASA Astrophysics Data System (ADS)

A comprehensive, multi-physics computational fuel cell dynamics (CFCD) model integrating electrochemical kinetics, charge transport, mass transport (particularly water transport), and flow dynamics is developed in this thesis. The numerical model is validated against published experimental data and utilized to generate results that reveal the internal operation of a PEM fuel cell. A number of model applications are demonstrated in the present work. First, the CFCD model is applied to explore hydrogen dilution effects in the anode feed. Detailed two-dimensional electrochemical and flow/transport simulations are provided to examine substantial anode concentration polarization due to hydrogen depletion at the reaction sites. A transient simulation of the cell current response to a step change in cell voltage is also attempted to elucidate characteristics of the dynamic response of a fuel cell for the first time. After the two-dimensional computational study, the CFCD model is applied to illustrate three-dimensional interactions between mass transfer and electrochemical kinetics. Emphasis is placed on obtaining a fundamental understanding of fully three-dimensional flow in the air cathode with interdigitated flowfield design and how it impacts the transport and electrochemical reaction processes. The innovative design concept for enhanced oxygen transport to, and effective water removal from the cathode, is explored numerically. Next, an analytical study of water transport is performed to investigate various water transport regimes of practical interest. The axial locations characteristic of anode water loss and cathode flooding are predicted theoretically and compared with numerical results. A continuous stirred fuel cell reactor (CSFCR) model is also proposed for the limiting situation where the anode and cathode sides reach equilibrium in water concentration with a thin ionomer membrane in between. In addition to the analytical solutions, a detailed water transport model extending the CFCD framework is developed in which a unified water equation is arrived at using the equilibrium water uptake curve between the gas and membrane phases. Various modes of water transport, i.e. diffusion, convection, and electro-osmotic drag, are incorporated in the unified water transport equation. This water transport model is then applied to elucidate water management in three-dimensional fuel cells with dry to low humidified inlet gases after its validation against available experimental data with dry oxidant and fuel streams. An internal circulation of water with the aid of counter-flow design is found to be essential for low-humidity operation, for example, in portable application of a PEM fuel cell without external humidifier. Finally, to handle the most important issue associated with PEM fuel cells using reformate gas, namely the CO poisoning anode Pt catalysts, a major modification of the present CFCD model is made to include CO oxidation processes. A four-step CO poisoning mechanism is implemented here and anode species equation for CO is added to model the electro- and chemical-oxidation processes on the anode. Numerical results of CO poisoning effects using a commercial package, STAR-CD, are presented. Basic features of CO poisoning are delineated and discussed. Future research areas of the fuel cell modeling are also indicated. As an example, preliminary results of extending the CFCD model to include heat transfer using a commercial package, FLUENTRTM, are given to demonstrate the need for careful thermal management in a multi-cell stack design.

Um, Sukkee

294

Navigating the transcriptional roadmap regulating plant secondary cell wall deposition  

PubMed Central

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

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

2013-01-01

295

The Lead-Lead Oxide Secondary Cell as a Teaching Resource  

ERIC Educational Resources Information Center

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…

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

2009-01-01

296

One step preparation and electrochemical analysis of IQS, a cell-cell communication signal in the nosocomial pathogen Pseudomonas aeruginosa.  

PubMed

Pseudomonas aeruginosa uses a hierarchical cell-cell communication system consisting of a number of regulatory elements to coordinate the expression of bacterial virulence genes. Sensitive detection of quorum sensing (QS) molecules has the potential for early identification of P. aeruginosa facilitating early medical intervention. A recently isolated cell-cell communication molecule, a thiazole termed IQS, can bypass the las QS system of P. aeruginosa under times of stress, activating a subset of QS-controlled genes. This compound offers a new target for pathogen detection and has been prepared in a one step protocol. A simple electrochemical strategy was employed for its sensitive detection using boron-doped diamond and glassy carbon electrodes by cyclic voltammetry and amperometry. PMID:25190465

Shang, Fengjun; Muimhneacháin, Eoin Ó; Reen, F Jerry; Buzid, Alyah; O'Gara, Fergal; Luong, John H T; Glennon, Jeremy D; McGlacken, Gerard P

2014-10-01

297

Fabrication of electrolytic cell for online post-column electrochemical derivatization in ion chromatography.  

PubMed

An electrolytic cell (EC), composed of two ruthenium-plated titanium electrodes separated by cation-exchange membranes, was fabricated and evaluated for online postcolumn derivatization in ion chromatography (IC). Folic acid (FA) and methotrexate (MTX) were preliminarily used as prototype analytes to test the performance of EC. After separation by an anion exchange column, FA and MTX, which emit very weak fluorescence when excited, were electrochemically oxidized online in the anode chamber of the EC. The compounds with strong fluorescence, which are oxidation products, were detected by the fluorescence detector. The phosphate buffer solution (100 mM KH(2)PO(4)) served as an optimal eluent for anion exchange chromatographic separation and a suitable supporting electrolyte for electro-oxidation, leading to ideal compatibility between IC separation and the postcolumn electrochemical derivatization. For the presently proposed method, the linear ranges were from 0.01 mg L(-1) to 5 mg L(-1) for both FA and MTX. The detection limits of FA and MTX were 1.8 and 2.1 ?g L(-1), and the relative standard deviations (RSD, n=7) were 2.9% and 3.6%, respectively. The method was applied for the simultaneous determination of FA and MTX in the plasma of patients being treated for rheumatoid arthritis. The determination of MTX in the urine of the patients of diffuse large B cell lymphoma was also demonstrated. PMID:22713918

Wu, Shuchao; Xu, Wei; Yang, Bingcheng; Ye, Mingli; Zhang, Peimin; Shen-Tu, Chao; Zhu, Yan

2012-07-20

298

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

DOEpatents

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.

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

1995-06-20

299

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

PubMed Central

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

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

2014-01-01

300

Electrochemical device  

DOEpatents

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.

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

1988-01-12

301

Structural and electrochemical study of Li-Al-Mn-O-F spinel material for lithium secondary batteries  

NASA Astrophysics Data System (ADS)

The structural and electrochemical properties of various Li-Al-Mn-O-F spinels were studied. Li[Li xAl yMn 2- x- y]O 4- zF z ( x = 0, 0.05, y = 0, 0.1, 0 ? z ? 0.2) spinels were synthesized by a solid-state reaction method. Fluorine substitution in Li[Li xAl yMn 2- x- y]O 4- zF z led to well-developed crystallization with octahedral morphology. In addition, Li[Li xAl yMn 2- x- y]O 4- zF z showed superior cycling performance and better thermal stability than LiMn 2O 4 and LiAl 0.1Mn 1.9O 4. Fluorine substitution also suppressed Mn dissolution which led to stable cycling performance at 55 °C. The differential scanning calorimetry (DSC) results showed that the anion (F for O) and cation (Li, Al for Mn) substituted spinel had better thermal stability than LiMn 2O 4, Li[Al yMn 2- y]O 4, or Li[Li xAl yMn 2- x- y]O 4.

Kang, Y.-J.; Kim, J.-H.; Sun, Y.-K.

302

The effect of Ni on the microstructures and electrochemical properties of Si-Ti base alloys for lithium secondary batteries.  

PubMed

This paper presents the microstructures and electrochemical properties of Si-Ti-Ni alloys of various compositions prepared by a rapid solidification process. Si-15Ti-(0-25 at%)Ni alloy ingots prepared by arc-melting was melt-spun to produce thin strip of -15 Om thickness. The Si-Ni-Ti alloy electrode were fabricated by mixing the active powdered materials (88 wt%) with ketjen black (4 wt%) as a conductive material and polyamide-imide binder (PAI, 8 wt.%) dissolved in N-methyl-2-pyrrolidinone (NMP). Results showed that the microstructures of melt-spun Si-Ti-Ni ribbons consist of silicon, TiSi2, Si7Ni4Ti4, and NiSi2 phases depending on the composition. As the content of nickel increased in silicon matrix, TiSi2 phase disappeared while Si7Ni4Ti4 and NiSi2 phases are generated. The cycle efficiency of Si65Ti15Ni20 and Si60Ti15Ni25 alloys was significantly improved because of the increased volume fraction of Si7Ni4Ti4 and NiSi2 phases and fine particulated silicon phase. PMID:23858893

Ahn, Deuk Kyu; Song, Jong-Jin; Ahn, Hyo-Jun; Cho, Jong Soo; Moon, Jeong Tak; Park, Won-Wook; Sohn, Keun Yong

2013-05-01

303

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

NASA Technical Reports Server (NTRS)

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.

Baldwin, Richard S.; Bennett, William R.

2007-01-01

304

Electrodes and electrochemical storage cells utilizing tin-modified active materials  

DOEpatents

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.

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

305

Solid oxide electrolysis cell analysis by means of electrochemical impedance spectroscopy: A review  

NASA Astrophysics Data System (ADS)

High temperature water electrolysis based on Solid Oxide Electrolysis Cell (SOEC) is a very promising solution to produce directly pure hydrogen. However, degradation issues occurring during operation still represent a scientific and technological barrier in view of its development at an industrial scale. Electrochemical Impedance Spectroscopy (EIS) is a powerful in-situ fundamental tool adapted to the study of SOEC systems. Hence, after a quick presentation of EIS principle and data analysis methods, this review demonstrates how EIS can be used: (i) to characterize the performance and mechanisms of SOEC electrodes; (ii) as a complementary tool to study SOEC degradation processes for different cell configurations, in addition to post-test tools such as scanning electron microscopy (SEM) or X-ray diffraction (XRD). The use of EIS to establish a systematic SOEC analysis is introduced as well.

Nechache, A.; Cassir, M.; Ringuedé, A.

2014-07-01

306

Volatile resistance states in electrochemical metallization cells enabling non-destructive readout of complementary resistive switches.  

PubMed

Redox-based resistive memory cells exhibit changes of OFF or intermediate resistance values over time and even ON states can be completely lost in certain cases. The stability of these resistance states and the time until resistance loss strongly depends on the materials system. On the basis of electrical measurements and chemical analysis we found a viable explanation for these volatile resistance states (VRSs) in Ag-GeSx-based electrochemical metallization memory cells and identified a technological application in the field of crossbar memories. Complementary resistive switches usually suffer from the necessity of a destructive read-out procedure increasing wear and reducing read-out speed. From our analysis we deduced a solution to use the VRS as an inherent selector mechanism without the need for additional selector devices. PMID:25266966

van den Hurk, Jan; Linn, Eike; Zhang, Hehe; Waser, Rainer; Valov, Ilia

2014-10-24

307

Paper-based analytical devices for electrochemical study of the breathing process of red blood cells.  

PubMed

Herein we utilized the filter paper to physically trap red blood cells (RBC) to observe the breathing process of red blood cells based on the permeability of the filter paper. By integrating double-sided conductive carbon tape as the working electrodes, the device could be applied to monitor electrochemical responses of RBC for up to hundreds of minutes. The differential pulse voltammetry (DPV) peak currents increased under oxygen while decreased under nitrogen, indicating that RBC could take in and release oxygen. Further studies demonstrated that the RBC suspension could more effectively take in oxygen than the solution of hemoglobin and the supernatant of RBC, suggesting the natural advantage of RBC on oxygen transportation. This study implied that simple paper-based analytical devices might be effectively applied in the study of gas-participating reactions and biochemical detections. PMID:25640121

Lin, Xiang-Yun; Wu, Ling-Ling; Pan, Zhong-Qin; Shi, Chuan-Guo; Bao, Ning; Gu, Hai-Ying

2015-04-01

308

EgMYB2, a new transcriptional activator from Eucalyptus xylem, regulates secondary cell wall formation and lignin  

E-print Network

EgMYB2, a new transcriptional activator from Eucalyptus xylem, regulates secondary cell wall Eucalyptus xylem. EgMYB2 maps to a unique locus on the Eucalyptus grandis linkage map and co and the regulation of secondary cell wall formation. Keywords: MYB, transcription, xylem, lignin, secondary cell wall

Paris-Sud XI, Université de

309

A new disposable electrode for electrochemical study of leukemia K562 cells and anticancer drug sensitivity test.  

PubMed

Developing cost-effective and simple analysis tools is of vital importance for practical applications in bioanalysis. In this work, a new disposable electrochemical cell sensor with low cost and simple fabrication was proposed to study the electrochemical behavior of leukemia K562 cells and the effect of anticancer drugs on cell viability. The analytical device was integrated by using ITO glass as the substrate of working electrodes and paper as the electrolytic cell. The cyclic voltammetry of the K562 cells at the disposable electrode exhibited an irreversible anodic peak and the peak current is proportional to the cell number. This anodic peak is attributed to the oxidation of guanine in cells involving two protons per transfer of two electrons. For the drug sensitivity tests, arsenic trioxide and cyclophosphamide were added to cell culture media. As a result, the electrochemical responses of the K562 cells decreased significantly. The cytotoxicity curves and results obtained corresponded well with the results of CCK-8 assays. In comparison to conventional methods, the proposed method is simple, rapid and inexpensive. More importantly, the developed sensor is supposed to be a single-use disposable device and electrodes were prepared "as new" for each experiment. We think that such disposable electrodes with these characteristics are suitable for experimental study with cancer cells or other types of pathogens for disease diagnosis, drug selection and on-site monitoring. PMID:24140828

Yu, Chunmei; Zhu, Zhenkun; Wang, Li; Wang, Qiuhong; Bao, Ning; Gu, Haiying

2014-03-15

310

Cell types of secondary cataract: an immunohistochemical analysis with antibodies to cytoskeletal elements and macrophages  

Microsoft Academic Search

• Background: The study was carried out to identify cell types of secondary cataract after extracapsular cataract extraction and implantation of an intraocular lens. • Methods: Twenty-five formalin-fixed, paraffin-embedded pseudophakic human eyes with secondary cataract, obtained at autopsy, were studied and compared to a specimen from an anterior subcapsular cataract with a panel of six monoclonal antibodies (MAbs, to vimentin,

Marita Uusitalo; Tero Kivelä

1997-01-01

311

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

PubMed Central

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

2014-01-01

312

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

PubMed

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

Kollender, Jan Philipp; Gasiorowski, Jacek; Sariciftci, Niyazi S; Mardare, Andrei I; Hassel, Achim Walter

2014-07-31

313

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

PubMed Central

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

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

2014-01-01

314

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

DOEpatents

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.

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

1998-01-01

315

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

SciTech Connect

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.

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

2002-06-21

316

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

DOEpatents

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.

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

1998-03-31

317

Improving Microchip Capillary Electrophoresis with Electrochemical Detection Using a Bubble Cell and Sample Stacking Techniques  

PubMed Central

Two efforts to improve the sensitivity and limits of detection for MCE with electrochemical detection are presented here. One is the implementation of a capillary expansion (bubble cell) at the detection zone to increase the exposed working electrode surface area. Bubble cell widths were varied from 1× to 10× the separation channel width (50 ?m) to investigate the effects of electrode surface area on detection sensitivity, LOD, and separation efficiency. Improved detection sensitivity and decreased detection limits were obtained with increased bubble cell width, and LODs of dopamine and catechol detected in a 5× bubble cell were 25 nM and 50 nM, respectively. Meanwhile, fluorescent imaging results demonstrated ~8% and ~12% loss in separation efficiency in 4× and 5× bubble cell, respectively. Another effort for reducing the LOD involves using field amplified sample injection (FASI) for gated injection and field amplified sample stacking (FASS) for hydrodynamic injection. Stacking effects are shown for both methods using amperometric detection and pulsed amperometric detection (PAD). The LODs of dopamine in a 4× bubble cell were 8 nM and 20 nM using FASI and FASS, respectively. However, improved LODs were not obtained for anionic analytes using either stacking technique. PMID:19802848

Guan, Qian; Henry, Charles S.

2010-01-01

318

Characterization of fluid dynamics and mass-transfer in an electrochemical oxidation cell by experimental and CFD studies  

Microsoft Academic Search

Flow and mass-transfer in a widely used commercial electrochemical flow cell (DiaCell®) were investigated by computational fluid dynamics (CFD) simulations and validated by experimental measurements. Both qualitative and quantitative comparisons were made for distinct flow regimes in the Reynolds range between 25 and 2500 (based on the inter-electrode distance and on the superficial velocity in the cell middle cross-section area).

J. L. C. Santos; V. Geraldes; S. Velizarov; J. G. Crespo

2010-01-01

319

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

NASA Technical Reports Server (NTRS)

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.

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

1969-01-01

320

Regulation of auxin on secondary cell wall cellulose biosynthesis in developing cotton fibers  

Technology Transfer Automated Retrieval System (TEKTRAN)

Cotton (Gossypium hirsutum L.) fibers are unicellular trichomes that differentiate from epidermal cells of developing cotton ovules. Mature fibers exhibit thickened secondary walls composed of nearly pure cellulose. Cotton fiber development is divided into four overlapping phases, 1) initiation sta...

321

Spontaneous electrochemical treatment for sulfur recovery by a sulfide oxidation/vanadium(V) reduction galvanic cell.  

PubMed

Sulfide is the product of the biological sulfate reduction process which gives toxicity and odor problems. Wastewaters or bioreactor effluents containing sulfide can cause severe environmental impacts. Electrochemical treatment can be an alternative approach for sulfide removal and sulfur recovery from such sulfide rich solutions. This study aims to develop a spontaneous electrochemical sulfide oxidation/vanadium(V) reduction cell with a graphite electrode system to recover sulfide as elemental sulfur. The effects of the internal and external resistance on the sulfide removal efficiency and electrical current produced were investigated at different pH. A high surface area of the graphite electrode is required in order to have as less internal resistance as possible. In this study, graphite powder was added (contact area >633 cm(2)) in order to reduce the internal resistance. A sulfide removal efficiency up to 91% and electrical charge of more than 400 C were achieved when using five graphite rods supplemented with graphite powder as the electrode at an external resistance of 30 ? and a sulfide concentration of 250 mg L(-1). PMID:25463589

Kijjanapanich, Pimluck; Kijjanapanich, Pairoje; Annachhatre, Ajit P; Esposito, Giovanni; Lens, Piet N L

2015-02-01

322

Improving the carrier balance of light-emitting electrochemical cells based on ionic transition metal complexes.  

PubMed

Recently, solid-state light-emitting electrochemical cells (LECs) based on ionic transition metal complexes (iTMCs) have attracted much research interest since they have the advantages of a simple device structure, a low operation voltage and compatibility with air-stable electrodes. These properties enable LECs to be cost-effective, versatile and power-efficient organic light-emitting sources. However, it is generally not easy to modify the molecular structure to achieve balanced carrier mobilities without altering the photoluminescence quantum yield of the iTMC. Furthermore, the carrier balance and the consequent device efficiency of single-layered LECs would not be easy to optimize since no carrier injection and transport layers can be used. In this perspective, some reported techniques to improve carrier balance of LECs based on iTMCs are described and reviewed. The importance and impact of these studies are highlighted. The effects on device lifetime and turn-on time because of employing these techniques to improve the carrier balance are also discussed. This perspective concludes that even with electrochemically doped layers, improving the carrier balance of LECs would be required for realizing efficient electroluminescent emission from simple-structure organic light-emitting sources. PMID:25407946

Su, Hai-Ching; Hsu, Jia-Hong

2014-11-13

323

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

NASA Astrophysics Data System (ADS)

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.

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

324

Ionic currents in secondary sensory hair cells isolated from the statocysts of squid and cuttlefish  

Microsoft Academic Search

Mechanosensitive hair cells in the statocysts of cephalopods underlie a sophisticated detection system for linear and angular accelerations. To investigate the operation of this system, secondary sensory hair cells were dissociated from the sensory epithelia of these statocysts and their voltage sensitive ionic conductances identified and characterized under whole cell voltage clamp.

R. Williamson

1995-01-01

325

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

NASA Astrophysics Data System (ADS)

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).

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

2014-10-01

326

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

PubMed

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

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

2014-10-01

327

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

PubMed Central

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

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

2015-01-01

328

Starting to gel: how Arabidopsis seed coat epidermal cells produce specialized secondary cell walls.  

PubMed

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

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

2015-01-01

329

Impedancemetric Technique for NOx Sensing Using a YSZ-Based Electrochemical Cell  

SciTech Connect

An impedancemetric technique for NO{sub x} sensing using a yttria-stabilized zirconia (YSZ) electrochemical cell is reported. The cell consists of a dense YSZ substrate disk with two YSZ/metal-oxide electrodes deposited on the same side. The cell is completely exposed to the test gas (no air reference). The NO{sub x} and O{sub 2} response of the cell were evaluated during constant-frequency operation at frequencies in the range from 1 to 1000 Hz. At 10 Hz, the NO{sub x} response (as measured by phase angle shift) is shown to be linear with concentration over the range from 8-50 ppm, with comparable response to both NO and NO{sub 2}. A method of operation is described which enables compensation for the O{sub 2} response at oxygen concentrations greater than approximately 4%. This mode of operation allows the sensor to provide sub-10 ppm detection of NO{sub x} irrespective of the O{sub 2} concentration. The sensor exhibits good stability during continuous operation for more than 150 hr. It was observed that the O{sub 2} response of the cell is too slow to be of practical use, taking several minutes to equilibrate after changing the concentration by a few percent. However, data will be presented which demonstrate that this response is related to the metal oxide used for the electrode; and more rapid response times can be achieved by modification of the electrode material.

Martin, L P; Woo, L Y; Glass, R S

2006-06-14

330

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

NASA Technical Reports Server (NTRS)

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.

Baldwin, Richard S.

1987-01-01

331

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

NASA Technical Reports Server (NTRS)

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.

Kang, M. P.; Winnick, J.

1985-01-01

332

THERMAL AND ELECTROCHEMICAL THREE DIMENSIONAL CFD MODEL OF A PLANAR SOLID OXIDE ELECTROLYSIS CELL  

SciTech Connect

A three-dimensional computational fluid dynamics (CFD) model has been created to model high-temperature steam electrolysis in a planar solid oxide electrolysis cell (SOEC). The model represents a single cell, as it would exist in an electrolysis stack. Details of the model geometry are specific to a stack that was fabricated by Ceramatec , Inc. and tested at the Idaho National Laboratory. Mass, momentum, energy, and species conservation and transport are provided via the core features of the commercial CFD code FLUENT2. 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, anode-side gas composition, cathode-side gas composition, current density and hydrogen production over a range of stack operating conditions. Mean model results are shown to compare favorably with experimental results obtained from an actual ten-cell stack tested at INL.

Grant Hawkes; Jim O'Brien; Carl Stoots; Steve Herring; Mehrdad Shahnam

2005-07-01

333

Comparison of electrochemical and surface characterisation methods for investigation of corrosion of bipolar plate materials in molten carbonate fuel cell  

Microsoft Academic Search

The corrosion of bipolar plate and current collector materials in molten carbonate fuel cells (MCFC) was investigated. Tafel extrapolation, linear polarisation resistance, chronopotentiometry and electrochemical impedance spectroscopy (EIS) were used to determine corrosion rates of iron and iron-based alloys in molten carbonate melts for both cathode and anode MCFC environments. During the initial stages, agreement among the methods was good

Baohua Zhu; Göran Lindbergh; Daniel Simonsson

1999-01-01

334

Creating systems that effectively convert energy, such as efficient solar cells and electrochemical batteries, has been a  

E-print Network

SEMTE abstract Creating systems that effectively convert energy, such as efficient solar cells stimuli, the solar energy from sunlight, and the mechanical motion is commonplace, indeed fundamental and electrochemical batteries, has been a longstanding scientific pursuit, especially given the global energy

Reisslein, Martin

335

Production of hydrogen by the electrochemical reforming of glycerol–water solutions in a PEM electrolysis cell  

Microsoft Academic Search

An alternative method for producing hydrogen from renewable resources is proposed. Electrochemical reforming of glycerol solution in a proton exchange membrane (PEM) electrolysis cell is reported. The anode catalyst was composed of Pt on Ru–Ir oxide with a catalyst loading of 3mgcm?2 on Nafion. Part of the energy carried by the produced hydrogen is supplied by the glycerol (82%) and

A. T. Marshall; R. G. Haverkamp

2008-01-01

336

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

E-print Network

Boosting the voltage of a salinity-gradient-power electrochemical cell by means of complex://scitation.aip.org/termsconditions. Downloaded to IP: 159.149.2.128 On: Wed, 22 Oct 2014 11:00:29 #12;Boosting the voltage of a salinity performances with respect to known salinity-difference-power methods. VC 2014 AIP Publishing LLC. [http

Carati, Andrea

337

Chemically desodiated thiochromites as cathode materials in secondary lithium cells  

NASA Astrophysics Data System (ADS)

The chemical desodiation of non-doped and vanadium-doped sodium thiochromites has been studied. The changes in the chemical composition and X-ray diffraction patterns during desodiation of the stoichiometric compound reveal that the vanadium-doped thiochromite can be more effectively desodiated. The presence of vanadium in the disulfide layers enhances the covalency of the M?S bond; this probably facilitates a first order phase transition of the vanadium-doped material during deintercalation of both Na + and Li +. The electrochemical performance of cathodes prepared from the chemically desodiated, vanadium-doped thiochromite is assessed by cycling in a 1 M LiClO 4/PC + DME solution at a 3 h rate between 1.8 and 3.4 V. The volumetric energy density of the pressed cathodes is 0.51 W h cm -3 at the 100th cycle and drops to 0.35 W h cm -3 after 500 cycles.

Moshtev, R.; Manev, V.; Nassalevska, A.; Gushev, A.; Pistoia, G.

1989-05-01

338

Simultaneous microbial and electrochemical reductions of vanadium (V) with bioelectricity generation in microbial fuel cells.  

PubMed

Simultaneous microbial and electrochemical reductions of vanadium (V) with bioelectricity generation were realized in microbial fuel cells (MFCs). With initial V(V) concentrations of 75 mg/l and 150 mg/l in anolyte and catholyte, respectively, stable power output of 419±11 mW/m(2) was achieved. After 12h operation, V(V) concentration in the catholyte decreased to the value similar to that of the initial one in the anolyte, meanwhile it was nearly reduced completely in the anolyte. V(IV) was the main reduction product, which subsequently precipitated, acquiring total vanadium removal efficiencies of 76.8±2.9%. Microbial community analysis revealed the emergence of the new species of Deltaproteobacteria and Bacteroidetes as well as the enhanced Spirochaetes mainly functioned in the anode. This study opens new pathways to successful remediation of vanadium contamination. PMID:25536507

Zhang, Baogang; Tian, Caixing; Liu, Ying; Hao, Liting; Liu, Ye; Feng, Chuanping; Liu, Yuqian; Wang, Zhongli

2015-03-01

339

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

SciTech Connect

Porous, rigid separators for electrochemical cells are prepared by first calcining particles of ceramic material at temperatures above about 1200* 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.

Bandyopadhyay, G.; Dusek, J.T.

1981-01-13

340

Analysis of different methods to calculate electrochemical noise resistance using a three-electrode cell  

SciTech Connect

In a theoretical approach, the noise resistance parameter (R{sub n}) (in time domain) was deduced from an electric equivalent model proposed by Bertocci and coworkers for a cell with three identical electrodes. The voltage and current were measured. The R{sub n} and resistance of spectral noise (R{sub sn} and R{sub snO} [defined elsewhere]) were estimated for mild steel (MS) and stainless steel (SS) Type 304L (UNS S30403) electrodes immersed in four different solutions. The obtained results were converted into corrosion rate and finally compared with data measured with linear polarization resistance (LRP) and mass loss techniques. Electrochemical noise (EN) techniques had better agreement with other techniques in high corrosion rates. Furthermore, dispersed results were measured in low-activity systems.

Brusamarello, V.; Lago, A.; Franco, C.V.

2000-03-01

341

New innovative materials for advanced electrochemical applications in battery and fuel cell systems  

NASA Astrophysics Data System (ADS)

The advanced material POLYMET is an innovative high tech polymer with a three-dimensional polymeric structure metallized with an enclosing coating of different kinds of metals or alloys. The result is a range of tailor-made, microporous structures on a designable scale. By varying the metals and alloys, it is possible to draw upon extremely diverse areas of applications such as battery systems, fuel cells, filters or efficient catalysts as well as air regeneration systems, e.g. in aerospace. The three-dimensional structure of metallized high tech woven or non-woven materials or foams causes a lot of advantages such as high conductivity, high corrosion resistance, flexibility or mechanical strength. Therefore, POLYMET is suitable for, e.g. current collectors or gas diffusion layers in energy storage systems. They supply an economic and environmental alternative material to improve functional electrochemical systems.

Voß, S.; Kollmann, H.; Kollmann, W.

342

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

DOEpatents

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.

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

1981-01-01

343

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

SciTech Connect

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.

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

2014-10-28

344

Effects of solution mass transport on the ECC ozonesonde background current. [Electrochemical Concentration Cell  

NASA Technical Reports Server (NTRS)

A technique is developed to measure the effective mass transport parameter for the electrochemical concentration cell (ECC) ozonesonde in order to determine the mass transport rate constant for the ECC as a function of pressure. It is shown that a pressure dependent factor in the background current originates in a convective mass transport parameter. It is determined that for atmospheric pressures greater than 100 mb the mass transport parameter is a constant, while at pressures less than 100 mb it decreases logarithmically with pressure. It is suggested that the background current correction is directly correlated to the mass transport parameter pressure dependence. The presently used background current correction, which is based on the partial pressure of oxygen, is found to lead to an overestimation of the integrated ozone value in the troposphere for the ECC ozonesonde data.

Thornton, D. C.; Niazy, N.

1983-01-01

345

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

PubMed Central

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

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

2013-01-01

346

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

NASA Technical Reports Server (NTRS)

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.

Isaac, Bryan J.

1994-01-01

347

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

NASA Astrophysics Data System (ADS)

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.

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

2015-03-01

348

The electrochemical intercalation of Li into graphite in Li/polymer electrolyte/graphite cells  

SciTech Connect

The electrochemical intercalation of Li into graphite has been studied in Li/polymer electrolyte/graphite cells using an in situ X-ray diffraction (XRD) technique. In cells containing an electrolyte of PAN (polyacrylonitrile)-EC (ethylene carbonate)-LiPF{sub 6}, a minor irreversible reduction of the electrolyte is observed only during the first discharge. In these cells, Li is reversibly intercalated into graphite to form Li{sub 1.0}C{sub 6}, principally at potentials between 0.2 and 0.0 V vs. Li{sup +}/Li. No evidence for the cointercalation of EC was obtained. In cells containing PAN-EC/PC(propylene carbonate)-LiPF{sub 6}-based electrolyte, a massive reduction of electrolyte occurs during the first discharge at {approximately}0.8 V vs. Li{sup +}/Li, which precludes Li intercalation into graphite. In situ XRD data are consistent with the absence of the intercalation of PC or Li{sup +}(PC){sub n} solvates into the graphite lattice, either prior to or during the solvent reduction process. The latter appears to be a surface-catalyzed process, the extent of which is determined by a combination of thermodynamic and kinetic factors including the reduction potential of the electrolyte, and the passivating films which form on the graphite surface as a result of electrolyte reduction.

Jiang, Z.; Alamgir, M.; Abraham, K.M. [EIC Labs., Inc., Norwood, MA (United States)

1995-02-01

349

Engineering of capillary-like structures in tissue constructs by electrochemical detachment of cells.  

PubMed

A major challenge in the development of functional thick tissues is the formation of vascular networks for oxygen and nutrient supply throughout the engineered tissue constructs. This study describes an electrochemical approach for fabrication of capillary-like structures, precisely aligned within micrometer distances, whose internal surfaces are covered with vascular endothelial cells. In this approach, an oligopeptide containing a cell adhesion domain (RGD) in the center and cysteine residues at both ends was designed. Cysteine has a thiol group that adsorbs onto a gold surface via a gold-thiolate bond. The cells attached to the gold surface via the oligopeptide were readily and noninvasively detached by applying a negative electrical potential and cleaving the gold-thiolate bond. This approach was applicable not only for a flat surface but also for various configurations, including cylindrical structures. By applying this approach to thin gold rods aligned in a spatially controlled manner in a perfusion culture device, human umbilical vein endothelial cells (HUVECs) were transferred onto the internal surface of capillary structures in collagen gel. In the subsequent perfusion culture, the HUVECs grew into the collagen gel and formed luminal structures, thereby forming vascular networks in vitro. PMID:20022631

Seto, Yuki; Inaba, Rina; Okuyama, Tomoaki; Sassa, Fumihiro; Suzuki, Hiroaki; Fukuda, Junji

2010-03-01

350

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

PubMed Central

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

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

2013-01-01

351

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

PubMed Central

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

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

2013-01-01

352

Coupled electrochemical and heat/mass transport characteristics in passive direct methanol fuel cells  

NASA Astrophysics Data System (ADS)

This thesis presents both experimental and theoretical investigations of coupled heat/mass transfer and electrochemical characteristics in the passive DMFC. Unlike active fuel cells, which can be operated under stabilized operating conditions, the discharging behavior of the passive DMFC usually varies with time, as the methanol concentration in the fuel reservoir decreases with time. This poses a difficulty in characterizing the performance of the passive DMFC under relatively stable operating conditions. In this work, we found that the performance of the passive DMFC became relatively stable as the cell operating temperature rose to a relatively stable value. This finding indicates that the performance of the passive DMFC can be characterized by collecting polarization data at the instance when the cell operating temperature under the open-circuit condition rises to a relatively stable value. With this proposed standard of passive DMFC performance characterization, the effects of two important parameters, including methanol concentration and cell orientation, on the passive DMFC performance were then investigated. It is found that the cell performance increased with methanol concentration. Unlike previous studies that attributed the improved performance as a result of increasing methanol concentration to the reduced anode mass transport polarization, our experimental results revealed that the improved cell performance was primarily due to the increased cell operating temperature as a result of the increased rate of methanol crossover with high methanol concentration operation. We also found that the performance was sensitive to the cell orientation. The vertical operation always yielded better performance than did the horizontal operation. This can be attributed to the increased operating temperature as a result of a higher rate of methanol crossover, which resulted from the stronger natural convection in the vertical orientation. These parametric studies indicated that the thermal management is a key factor for improving the performance of the passive DMFC. To enhance oxygen transport on the air-breathing cathode and to reduce the heat loss from the cathode, a porous current collector for the passive DMFC was proposed to replace conventional perforated-plate current collectors. Because of its high specific area of transport and effectiveness in removing the liquid water as a result of the capillary action in the porous structure, the porous current collector enables a significant enhancement of oxygen supply to the fuel cell. In addition, because of the lower effective thermal conductivity of the porous structure, the heat loss from the fuel cell to ambient air can be reduced. The experimental results showed that the passive DMFC having the porous current collector yielded much higher and much more stable performance than did the cell having the conventional perforated-plate current collector with high methanol concentration operation. As a following up to oxygen transport enhancement, a new design of membrane electrode assembly (MEA) was proposed, in which the conventional cathode gas diffusion layer (CGDL) is eliminated while utilizing a porous metal structure for transporting oxygen and collecting current. We show theoretically that the new MEA enables a higher mass transfer rate of oxygen and thus better performance. Moreover, the measured polarization and constant-current discharging behavior showed that the passive DMFC with the new MEA yielded higher and much more stable performance than did the cell having the conventional MEA. Besides the experimental investigations, to further theoretically study the thermal effect on the cell performance, a one-dimension single-phase model is developed by considering inherently coupled heat and mass transport along with the electrochemical reactions occurring in passive DMFCs. The analytical solutions predicting the performance of this type of fuel cell operating with different methanol concentrations are obtained. It was further revealed that the improved performance with

Chen, Rong

353

Space applications of electrochemical generators  

NASA Astrophysics Data System (ADS)

Reliability is the key requirement for the use of electrochemical generators in space (e.g., on space shuttles, satellites, and launchers). This requirement imposes the use of well-known well-mastered technologies, such as Ni-Cd batteries. Low battery weight is also a very important requirement, leading to the use of more advanced technologies, such as nickel-hydrogen batteries for geostationary satellites and fuel cells for space shuttles. Current research on new batteries is devoted mainly to secondary lithium batteries and sodium-sulfur batteries.

Fauvarque, Jean-Francois; Goualard, Jacques

1992-12-01

354

Aging Studies of Sr-doped LaCrO3\\/YSZ\\/Pt Cells for an Electrochemical NOx Sensor  

Microsoft Academic Search

The stability and NOâ sensing performance of electrochemical cells of the structure Sr-doped LaCrO{sub 3-δ} (LSC)\\/yttria-stabilized zirconia (YSZ)\\/Pt are being investigated for use in NOâ aftertreatment systems in diesel vehicles. Among the requirements for NOâ sensor materials in these systems are stability and long lifetime (up to ten years) in the exhaust environment. In this study, cell aging effects were

Seung-Wan Song; L. Peter Martin; Robert S. Glass; Erica P. Murray; Jaco H. Visser; Richard E. Soltis; Robert F. Novak; D J Kubinski

2005-01-01

355

Engineering the Oryza sativa cell wall with rice NAC transcription factors regulating secondary wall formation  

PubMed Central

Plant tissues that require structural rigidity synthesize a thick, strong secondary cell wall of lignin, cellulose and hemicelluloses in a complicated bridged structure. Master regulators of secondary wall synthesis were identified in dicots, and orthologs of these regulators have been identified in monocots, but regulation of secondary cell wall formation in monocots has not been extensively studied. Here we demonstrate that the rice transcription factors SECONDARY WALL NAC DOMAIN PROTEINs (SWNs) can regulate secondary wall formation in rice (Oryza sativa) and are potentially useful for engineering the monocot cell wall. The OsSWN1 promoter is highly active in sclerenchymatous cells of the leaf blade and less active in xylem cells. By contrast, the OsSWN2 promoter is highly active in xylem cells and less active in sclerenchymatous cells. OsSWN2 splicing variants encode two proteins; the shorter protein (OsSWN2S) has very low transcriptional activation ability, but the longer protein (OsSWN2L) and OsSWN1 have strong transcriptional activation ability. In rice, expression of an OsSWN2S chimeric repressor, driven by the OsSWN2 promoter, resulted in stunted growth and para-wilting (leaf rolling and browning under normal water conditions) due to impaired vascular vessels. The same OsSWN2S chimeric repressor, driven by the OsSWN1 promoter, caused a reduction of cell wall thickening in sclerenchymatous cells, a drooping leaf phenotype, reduced lignin and xylose contents and increased digestibility as forage. These data suggest that OsSWNs regulate secondary wall formation in rice and manipulation of OsSWNs may enable improvements in monocotyledonous crops for forage or biofuel applications. PMID:24098302

Yoshida, Kouki; Sakamoto, Shingo; Kawai, Tetsushi; Kobayashi, Yoshinori; Sato, Kazuhito; Ichinose, Yasunori; Yaoi, Katsuro; Akiyoshi-Endo, Miho; Sato, Hiroko; Takamizo, Tadashi; Ohme-Takagi, Masaru; Mitsuda, Nobutaka

2013-01-01

356

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

SciTech Connect

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.

Aaron, D [Georgia Institute of Technology; Borole, Abhijeet P [ORNL; Yiacoumi, Sotira [Georgia Institute of Technology; Tsouris, Costas [ORNL

2012-01-01

357

Conceptual difficulties experienced by senior high school students of electrochemistry: Electrochemical (galvanic) and electrolytic cells  

NASA Astrophysics Data System (ADS)

This research investigated students' understanding of electrochemistry following a 7-9-week course of instruction. A list of conceptual and propositional knowledge statements was formulated, and this provided the framework for semistructured interviews that were conducted with 32 students in their final year of high school chemistry, following instruction in electrochemistry. Three misconceptions identified in this study and five which have been reported earlier are incorporated into an alternative framework about electric current. The framework is grounded on the notion that a current always involves drifting electrons, even in solution. Another area where students' misconceptions were prevalent was in relation to the sign of the anode and cathode. Students who thought the anode was negatively charged believed cations would move toward it, and those who thought it was positively charged were unable to explain why electrons move away from it. Electrolytic cells also proved troublesome for students. Many students did not associate the positions of the anode and cathode with the polarity of the applied electromotive force (e.m.f.). Other students attempted to reverse features of electrochemical cells and apply the reversals to electrolytic cells. The implications of the research relate to students' interpretation of the language that is used to describe scientific phenomena and the tendency for students to overgeneralize, due to comments made by teachers or statements in textbooks.

Garnett, Pamela J.; Treagust, David F.

358

Embolization for Treatment of Gastrointestinal Hemorrhage Secondary to Recurrent Renal Cell Carcinoma  

SciTech Connect

Massive gastrointestinal hemorrhage secondary to metastatic renal cell carcinoma involving the jejunum is rare but has been previously described in the medical literature. Treatment options for metastatic renal cell carcinoma are limited, but transcatheter arterial embolization can be performed to control gastrointestinal hemorrhage either alone or prior to surgical resection. We describe a case of successful transcatheter arterial embolization for control of massive gastrointestinal hemorrhage secondary to locally recurrent renal cell carcinoma invading the jejunum and review the literature. Arteriography provided both the diagnosis of recurrent disease and the means of therapy.

Kobak, Jeff [SUNY Downstate Health Science Center, Department of Radiology (United States); Gandras, Eric J. [North Shore University Hospital, Department of Radiology (United States)], E-mail: egandrobi@aol.com; Fleury, Linwald; Macura, Jerzy [Maimonides Medical Center, Department of Surgery (United States); Shams, Joseph [Beth Israel Medical Center, Department of Radiology (United States)

2006-12-15

359

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

DOEpatents

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.

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

360

Synchronously detected secondary signet ring cell urinary bladder malignancy from the stomach masquerading as genitourinary tuberculosis.  

PubMed

Secondary bladder neoplasms are very rare and represent 1% of all malignant bladder tumours. Among secondary bladder tumours, metastasis from the stomach accounts for about 4% of cases. These secondary tumours are generally detected during follow-up of patients already treated for gastric cancer. We report a case of metastatic adenocarcinoma of the urinary bladder from an occult primary poorly differentiated signet ring cell type gastric carcinoma masquerading clinically as genitourinary tuberculosis. Our case illustrates the importance of obtaining a bladder biopsy in suspected chronic inflammatory conditions such as urinary tract tuberculosis before starting medical management to avoid the serious consequences of missing a bladder malignancy. PMID:25618874

Kalra, Sidhartha; Manikandan, Ramanitharan; Dorairajan, Lalgudi Narayanan; Badhe, Bhavana

2015-01-01

361

IL-4-Secreting Secondary T Follicular Helper (Tfh) Cells Arise from Memory T Cells, Not Persisting Tfh Cells, through a B Cell-Dependent Mechanism.  

PubMed

Humoral immunity requires cross-talk between T follicular helper (Tfh) cells and B cells. Nevertheless, a detailed understanding of this intercellular interaction during secondary immune responses is lacking. We examined this by focusing on the response to a soluble, unadjuvanted, pathogen-derived Ag (soluble extract of Schistosoma mansoni egg [SEA]) that induces type 2 immunity. We found that activated Tfh cells persisted for long periods within germinal centers following primary immunization. However, the magnitude of the secondary response did not appear to depend on pre-existing Tfh cells. Instead, Tfh cell populations expanded through a process that was dependent on memory T cells recruited into the reactive LN, as well as the participation of B cells. We found that, during the secondary response, IL-4 was critical for the expansion of a population of plasmablasts that correlated with increased SEA-specific IgG1 titers. Additionally, following immunization with SEA (but not with an Ag that induced type 1 immunity), IL-4 and IL-21 were coproduced by individual Tfh cells, revealing a potential mechanism through which appropriate class-switching can be coupled to plasmablast proliferation to enforce type 2 immunity. Our findings demonstrate a pivotal role for IL-4 in the interplay between T and B cells during a secondary Th2 response and have significant implications for vaccine design. PMID:25712216

Fairfax, Keke C; Everts, Bart; Amiel, Eyal; Smith, Amber M; Schramm, Gabriele; Haas, Helmut; Randolph, Gwendalyn J; Taylor, Justin J; Pearce, Edward J

2015-04-01

362

Photosynthetic Electron Transport in Single Guard Cells as Measured by Scanning Electrochemical Microscopy.  

PubMed Central

Scanning electrochemical microscopy (SECM) is a powerful new tool for studying chemical and biological processes. It records changes in faradaic current as a microelectrode ([less than equal]7 [mu]m in diameter) is moved across the surface of a sample. The current varies as a function of both distance from the surface and the surface's chemical and electrical properties. We used SECM to examine in vivo topography and photosynthetic electron transport of individual guard cells in Tradescantia fluminensis, to our knowledge the first such analysis for an intact plant. We measured surface topography at the micrometer level and concentration profiles of O2 evolved in photosynthetic electron transport. Comparison of topography and oxygen profiles above single stomatal complexes clearly showed photosynthetic electron transport in guard cells, as indicated by induction of O2 evolution by photosynthetically active radiation. SECM is unique in its ability to measure topography and chemical fluxes, combining some of the attributes of patch clamping with scanning tunneling microscopy. In this paper we suggest several questions in plant physiology that it might address. PMID:12223651

Tsionsky, M.; Cardon, Z. G.; Bard, A. J.; Jackson, R. B.

1997-01-01

363

Triphenylamine-based organic dyes with julolidine as the secondary electron donor for dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

Two novel donor-donor-?-conjugated-acceptor (D-D-?-A) metal-free organic dyes (JTPA1 and JTPA2) with a julolidine moiety as the secondary electron donor for dye-sensitized solar cells (DSSCs) are synthesized. Their absorption spectra, electrochemical and photovoltaic properties are extensively investigated and compared with TPA2 dye. Transient absorption measurements show that both sensitizers are quickly regenerated and the dye cations are efficiently intercepted by the redox mediator. Both dyes show good performance as DSSC photosensitizers. In particular, a DSSC using JTPA2 with rhodanine-3-acetic acid shows better photovoltaic performance with a short-circuit photocurrent density (Jsc) of 9.30 mA cm-2, an open-circuit photovoltage (Voc) of 509 mV and a fill factor (FF) of 0.68, corresponding to an overall conversion efficiency (?) of 3.2% under AM 1.5 irradiation (100 mW cm-2). Under similar test conditions, ruthenium-based N719 dye gives an efficiency of 6.7%. Compared to TPA2, the dye regeneration rate, the short-circuit photocurrent density and the conversion efficiency of JTPA2 are doubled by introducing a julolidine unit. Our findings show that the julolidine unit may be an excellent electron donor system for organic dyes harvesting solar irradiation.

Wu, Guohua; Kong, Fantai; Li, Jingzhe; Fang, Xiaqin; Li, Yi; Dai, Songyuan; Chen, Qianqian; Zhang, Xianxi

2013-12-01

364

Physical, mechanical and electrochemical characterization of all-perovskite intermediate temperature solid oxide fuel cells  

NASA Astrophysics Data System (ADS)

Strontium- and magnesium-doped lanthanum gallate (LSGM) has been considered as a promising electrolyte for solid oxide fuel cell (SOFC) systems in recent years due to its high ionic conductivity and chemical stability over a wide range of oxygen partial pressures and temperatures. This research describes synthesis, physical and mechanical behavior, electrochemical properties, phase evolution, and microstructure of components of an all-perovskite anode-supported intermediate temperature solid oxide fuel cell (ITSOFC), based on porous La 0.75Sr0.25Cr0.5Mn0.5O3 (LSCM) anode, La0.8Sr0.2Ga0.8Mg0.2O 2.8 (LSGM) electrolyte, and porous La0.6Sr0.4Fe 0.8Co0.2O3 (LSCF) cathode. The phase evolution of synthesized LSGM and LSCM powders has been investigated, and it has been confirmed that there is no reaction between LSGM and LSCM at sintering temperature. Using different amounts of poreformers and binders as well as controlling firing temperature, porosity of the anode was optimized while still retaining good mechanical integrity. The effect of cell operation conditions under dry hydrogen fuel on the SOFC open circuit voltage (OCV) and cell performance were also investigated. Characterization study of the synthesized LSGM indicates that sintering at 1500°C obtains higher electrical conductivity compared to the currently published results, while conductivity of pellets sintered at 1400°C and 1450°C would be slightly lower. The effect of sintering temperature on bulk and grain boundary resistivities was also discussed. The mechanical properties, such as hardness, Young's modulus, fracture toughness and modulus of rupture of the electrolyte were determined and correlated with scanning electron microscopy (SEM) morphological characterization. Linear thermal expansion and thermal expansion coefficient of LSGM were also measured.

Mohammadi, Alidad

365

Electrochemical sensors, MTT and immunofluorescence assays for monitoring the proliferation effects of cissus populnea extracts on Sertoli cells  

PubMed Central

Background We describe the development of an electrochemical sensor array for monitoring the proliferation effects of cissus populnea plant extracts on TM4 Sertoli cells. Methods The proliferation activities of the extracts on Sertoli cells were studied using a high-throughput electrochemical sensor array (DOX-96) and the analytical sensor characteristics were compared with conventional colorimetric MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and fluorescence spectroscopy. Results This work shows that there is a definite positive trend in the proliferation effect of the extract of Cissus populnea on the TM4 Sertoli cells. All of the three techniques confirmed that the most effective concentration for the proliferation is 10 ppm. At this concentration, the proliferation effect was established around 120% for both DOX-96 and MTT techniques, whereas fluorescence assays showed a higher level (120-150%). DOX-96 showed a lower limit of detection (1.25 × 10(4) cells/ml); whereas the LOD recorded for both MTT and fluorescence techniques was 2.5 × 10(4) cells/ml. Visual examination of the cells by means of confocal fluorescence microscopy confirmed the proliferation of Sertoli cells as was determined using the MTT assay. This investigation provides a confident interpretation of the results and proved that the most effective concentration for the proliferation using Cissus populnea plant extract is 10 ppm. Conclusions Overall, the DOX results compared well with the conventional methods of checking proliferation of cells. The fascinating feature of the sensor array is the ability to provide continuous proliferation experiments with no additional reagents including 96 simultaneous electrochemical experiments. The use of the DOX-96 could reduce a typical bioassay time by 20-fold. Thus the DOX-96 can be used as both a research tool and for practical cell culture monitoring. PMID:21575213

2011-01-01

366

Roles of microtubules and cellulose microfibril assembly in the localization of secondary-cell-wall deposition in developing tracheary elements  

Microsoft Academic Search

Summary. The roles of cellulose microfibrils and cortical microtubules in establishing and maintaining the pattern of secondary-cell-wall deposition in tracheary elements were investigated with direct dyes to inhibit cellulose microfibril assembly and amiprophosmethyl to inhibit microtubule polymerization. When direct dyes were added to xylogenic cultures of Zinnia elegans L. mesophyll cells just before the onset of differentiation, the secondary cell

A. W. Roberts; A. O. Frost; E. M. Roberts; C. H. Haigler

2004-01-01

367

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

DOEpatents

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.

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

2014-01-21

368

Optimization of microstructure of buckypaper-based proton exchange membrane fuel cell by using electrochemical impedance spectroscopy  

NASA Astrophysics Data System (ADS)

The microstructure of the catalyst layer in proton exchange membrane fuel cells (PEMFCs) greatly influences the utilization of the catalyst (Pt) and the overall cell performance. Research focused on two key components in optimizing the microstructure of PEMFCs, primarily the platinum loading and Nafion loading. An electrochemical impedance spectroscopy (EIS) experiment was performed, in order to study the effects of varying these two components and come to a conclusion on the optimal amount required to maximize cell performance of PEMFC's that are based on double-layered supported Pt (Pt/DLBP) catalyst.

Hagen, Mark

369

Electrochemical response of zirconia-coated 316L stainless-steel in a simulated proton exchange membrane fuel cell environment  

Microsoft Academic Search

The corrosion resistance of zirconia-coated austenitic stainless-steel 316L was investigated in a simulated proton exchange membrane fuel cell (PEMFC) environment. The zirconia coating was performed using a sol–gel dip coating method and electrochemical tests were carried out at 80°C in 1M H2SO4 solution to accelerate corrosion. The results showed that the precursor containing zirconium alkoxide and zirconium acetate hydroxide changed

W. G. Lee; K. H. Cho; S. B. Lee; S. B. Park; H. Jang

2009-01-01

370

Development of enzyme immobilized monolith micro-reactors integrated with microfluidic electrochemical cell for the evaluation of enzyme kinetics  

Microsoft Academic Search

This paper describes a simple and efficient method for producing an on-chip enzyme immobilized monolith micro-reactor that\\u000a integrates a microfluidic electrochemical cell for rapid characterization of enzymatic kinetics. The monolith was generated\\u000a using a sol–gel method, followed by PEI functionalization and enzyme immobilization via electrostatic attraction between electronegative\\u000a enzymes and electropositive PEI polymers. Using the proposed immobilization strategy, a glucose

Ping He; Gillian Greenway; Stephen J. Haswell

2010-01-01

371

Evaluation program for secondary spacecraft cells: Cycle life test  

NASA Technical Reports Server (NTRS)

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.

Harkness, J. D.

1979-01-01

372

Electrochemical Processes for Removing  

E-print Network

using chemical additives, including: acids, bases, ferric chloride or alum coagulants, and antiscalant, electrochemical ion exchange regeneration (ELIXR), utilizes an electrochemical cell to generate the acid and base to ban water softeners that use salts or acids for regeneration (ii). Municipal and industrial water

Fay, Noah

373

Enhancing electrochemical performance by control of transport properties in buffer layers - solid oxide fuel/electrolyser cells.  

PubMed

The current work demonstrates how tailoring the transport properties of thin ceria-based buffer layers in solid oxide fuel or electrolyser cells can provide the necessary phase stability against chemical interaction at the electrolyte/electrode interface, while also providing radical improvements in the electrochemical performance of the oxygen electrode. Half cells of Ce0.8R0.2O2-? + 2 mol% Co buffer layers (where R = Gd, Pr) with Nd2NiO4+? electrodes were fabricated by spin coating on dense YSZ electrolyte supports. Dramatic decreases in polarization resistance, Rp, of up to an order of magnitude, could be achieved in the order, Pr ? Gd < no buffer layer. The current article shows how this improvement can be related to increased levels of ambipolar conductivity in the mixed conducting buffer layer, which provides an additional parallel path for electrochemical reaction. This is an important breakthrough as it shows how electrode polarization resistance can be substantially improved, in otherwise identical electrochemical cells, solely by tailoring the transport properties of thin intermediate buffer layers. PMID:25857870

Ramasamy, Devaraj; Nasani, Narendar; Brandão, Ana D; Pérez Coll, Domingo; Fagg, Duncan P

2015-04-21

374

Secondary metabolite localization by autofluorescence in living plant cells.  

PubMed

Autofluorescent molecules are abundant in plant cells and spectral images offer means for analyzing their spectra, yielding information on their accumulation and function. Based on their fluorescence characteristics, an imaging approach using multiphoton microscopy was designed to assess localization of the endogenous fluorophores in living plant cells. This method, which requires no previous treatment, provides an effective experimental tool for discriminating between multiple naturally-occurring fluorophores in living-tissues. Combined with advanced Linear Unmixing, the spectral analysis extends the possibilities and enables the simultaneous detection of fluorescent molecules reliably separating overlapping emission spectra. However, as with any technology, the possibility for artifactual results does exist. This methodological article presents an overview of the applications of tissular and intra-cellular localization of these intrinsic fluorophores in leaves and fruits (here for coffee and vanilla). This method will provide new opportunities for studying cellular environments and the behavior of endogenous fluorophores in the intracellular environment. PMID:25808147

Talamond, Pascale; Verdeil, Jean-Luc; Conéjéro, Geneviève

2015-01-01

375

A wound-type lithium\\/polyaniline secondary cell  

Microsoft Academic Search

A wound-type cell with a polyaniline (PAn) positive electrode, a LiClON4-propylene carbonate (PC) electrolyte, and a lithium-foil negative electrode is constructed. The two electrodes are separated by a polypropylene separator. The PAn is deposited on carbon felt from a HClON4 solution containing aniline by galvanostatic or potentiostatic electrolysis. Using cyclic voltammetry charge\\/discharge cycles and charge\\/retention tests, the following results are

Changzhi Li; Borong Zhang; Baochen Wang

1992-01-01

376

Hermetically sealed electrical feedthrough for high temperature secondary cells  

DOEpatents

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.

Knoedler, Reinhard (Nussloch, DE); Nelson, Paul A. (Wheaton, IL); Shimotake, Hiroshi (Hinsdale, IL); Battles, James E. (Oak Forest, IL)

1985-01-01

377

Hermetically sealed electrical feedthrough for high temperature secondary cells  

DOEpatents

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.

Knoedler, R.; Nelson, P.A.; Shimotake, H.; Battles, J.E.

1983-07-26

378

The toughness of secondary cell wall and woody tissue  

PubMed Central

The 'across grain' toughness of 51 woods has been determined on thin wet sections using scissors. The moisture content of sections and the varying sharpness of the scissor blades had little effect on the results. In thin sections (less than 0.6mm), toughness rose linearly with section thickness. The intercept toughness at zero thickness, estimated from regression analysis, was proportional to relative density, consistent with values reported for non-woody plant tissues. Extrapolation of the intercept toughness of these woods and other plant tissues/materials to a relative density of 1.0 predicted a toughness of 3.45kJ m-2 , which we identify with the intrinsic toughness of the cell wall. This quantity appears to predict published results from KIC tests on woods and is related to the propensity for crack deflection. The slope of the relationship between section thickness and toughness, describing the work of plastic buckling of cells, was not proportional to relative density, the lightest (balsa) and heaviest (lignum vitae) woods fracturing with less plastic work than predicted. The size of the plastic zone around the crack tip was estimated to be 0.5mm in size. From this, the hypothetical overall toughness of a thick (greater than 1 mm) block of solid cell wall material was calculated as 39.35 kJ m-2, due to both cell wall resistance (10 per cent) and the plastic buckling of cells (90 per cent). This value successfully predicts the toughness of most commercial woods (of relative densities between 0.2 and 0.8) from 'work area' tests in tension and bending. Though density was the most important factor, both fibre width/fibre length (in hardwoods) and lignin/cellulose ratios were negatively correlated with the work of plastic buckling, after correcting for density. At low densities the work of plastic buckling in the longitudinal radial (LR) direction exceeded that in longitudinal tangential (LT), but the reverse was true for relative densities above 0.25. This could be attributed to the direction of rays. Density for density, the toughness of temperate hardwoods tested was about 20 per cent lower than that of tropical hardwoods. This is probably due to the much greater number of vessels in temperate hardwoods. Vessels appear either not to display buckling behaviour during fracture at all or to collapse cheaply. These general results have applications to other plant tissues.

Lucas, P. W.; Tan, H. T. W.; Cheng, P. Y.

1997-01-01

379

Electrochemical performance of microbial fuel cells based on disulfonated poly(arylene ether sulfone) membranes  

NASA Astrophysics Data System (ADS)

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).

Choi, Tae Hwan; Won, Young-Bin; Lee, Jin-Won; Shin, Dong Won; Lee, Young Moo; Kim, Minkyong; Park, Ho Bum

2012-12-01

380

Method of bonding a conductive layer on an electrode of an electrochemical cell  

DOEpatents

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.

Bowker, J.C.; Singh, P.

1989-08-29

381

Method of bonding a conductive layer on an electrode of an electrochemical cell  

DOEpatents

A dense, electronically conductive interconnection layer 26 is bonded onto a porous, tubular, electronically conductive air electrode structure 16, optionally supported by a ceramic support 22, by (A) providing an air electrode surface, (B) forming on a selected portion of the electrode surface 24, 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.degree. C. to 1,550.degree. C., without the application of pressure, to provide a dense, sintered, interconnection material 26 bonded to the air electrode 16, where calcium and chromium from the surface deposit are incorporated into the structure of the LaCrO.sub.3. 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.

Bowker, Jeffrey C. (Richland Township, Allegheny County, PA); Singh, Prabhakar (Pittsburgh, PA)

1989-01-01

382

Separation of competitive microorganisms using anaerobic membrane bioreactors as pretreatment to microbial electrochemical cells.  

PubMed

Anaerobic membrane bioreactors (AnMBRs) as pretreatment to microbial electrochemical cells (MECs) were first assessed for improving energy recovery. A dual-chamber MEC was operated at hydraulic retention time (HRT) ranging from 1 to 8d, while operating conditions for an AnMBR were fixed. Current density was increased from 7.5 ± 0 to 14 ± 1A/m(2) membrane with increasing HRT. MEC tests with AnMBR permeate (mainly propionate and acetate) and propionate medium confirmed that propionate was fermented to acetate and hydrogen gas, and anode-respiring bacteria (ARB) utilized these fermentation products as substrate. Membrane separation in the AnMBR excluded fermenters and methanogens from the MEC, and thus no methane production was found in the MEC. The lack of fermenters, however, slowed down propionate fermentation rate, which limited current density in the MEC. To symphonize fermenters, H2-consumers, and ARB in biofilm anode is essential for improving current density, and COD removal. PMID:24047682

Dhar, Bipro Ranjan; Gao, Yaohuan; Yeo, Hyeongu; Lee, Hyung-Sool

2013-11-01

383

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

PubMed

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

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

384

Electrochemical heat engines. [Voltage of discharging cell is higher than charging voltage, difference is made up by heat converted to work which assists in charging; 2Ag + I. -->. 2AgI reaction tested  

Microsoft Academic Search

Any nearly reversible electrochemical cell reaction involving a significant entropy change can, in principle, be made the basis of a heat engine. Usual Carnot cycle efficiency limits apply, and the appropriate thermodynamic equations are very similar to those for Ford's sodium heat engine or for usual heat-to-work cycles in physical chemistry textbooks. Electrochemical heat engines produce electrochemical rather than mechanical

G. R. B

1976-01-01

385

CELL PHONES IN NEW ZEALAND SECONDARY SCHOOLS: BOON, BANNED OR BIASED  

Microsoft Academic Search

In this qualitative research study conducted in twelve New Zealand secondary schools data was gathered on policy formation on a range of issues including: cell phone usage at school; mobile technology incorporated into learning; staff development; curriculum development; assessment, school and class management; and registration and enrolment. Participants included: school principals; deans; heads of department; guidance officers; teachers; and prior

K. FIELDEN; P. MALCOLM

2007-01-01

386

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-...

387

Secondary Philadelphia chromosome and erythrophagocytosis in a relapsed acute myeloid leukemia after hematopoietic cell transplantation.  

PubMed

The acquisition of the Philadelphia chromosome (Ph) as a secondary change during the course of hematopoietic malignancies is rare and is associated with poor prognosis. Few cases of secondary Ph have been reported after hematopoietic cell transplantation (HCT). A secondary Ph at relapse is of clinical importance because it provides a therapeutic target for tyrosine kinase inhibitors along with or in replacement of chemotherapy. We describe a case of relapsed acute myeloid leukemia (AML) after HCT that developed a BCR-ABL1 translocation along with erythrophagocytosis by blasts as a secondary change at the time of relapse. The progression of this patient's myeloid neoplasm from myelodysplastic syndrome to AML to relapsed AML after HCT was accompanied by a stepwise cytogenetic evolution: A deletion 20q abnormality subsequently acquired a deletion 7q and, finally, at relapse after HCT, a secondary Ph was gained. The relationship between the secondary Ph and the erythrophagocytosis by blasts is not clear. We review the possible pathogenesis and cytogenetic associations of erythrophagocytosis by blasts, a rare feature in acute leukemias. PMID:25074248

Kelemen, Katalin; Galani, Komal; Conley, Christopher R; Greipp, Patricia T

2014-06-01

388

Promoting Effect of Layered Titanium Phosphate on the Electrochemical and Photovoltaic Performance of Dye-Sensitized Solar Cells  

NASA Astrophysics Data System (ADS)

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.

Cheng, Ping; Chen, Ruihao; Wang, Junfei; Yu, Jianong; Lan, Tian; Wang, Wanjun; Yang, Haijun; Wu, Haixia; Deng, Changsheng

2010-08-01

389

Pinoresinol reductase 1 impacts lignin distribution during secondary cell wall biosynthesis in Arabidopsis.  

PubMed

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

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

390

Regeneration of anion exchange resins by catalyzed electrochemical reduction  

DOEpatents

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.

Gu, Baohua (Oak Ridge, TN); Brown, Gilbert M. (Knoxville, TN)

2002-01-01

391

Comparisons of optical pH and dissolved oxygen sensors with traditional electrochemical probes during mammalian cell culture.  

PubMed

Small-scale upstream bioprocess development often occurs in flasks and multi-well plates. These culturing platforms are often not equipped to accurately monitor and control critical process parameters; thus they may not yield conditions representative of manufacturing. In response, we and others have developed optical sensors that enable small-scale process monitoring. Here we have compared two parameters critical to control in industrial cell culture, pH and dissolved oxygen (DO), measured with our optical sensors versus industrially accepted electrochemical probes. For both optical sensors, agreement with the corresponding electrochemical probe was excellent. The Pearson Correlations between the optical sensors and electrochemical probes were 98.7% and 99.7%, for DO and pH, respectively. Also, we have compared optical pH sensor performance in regular (320 mOsm/kg) and high-osmolality (450 mOsm/kg) cell culture media to simulate the increase in osmolality in pH-controlled cultures. Over a pH range of 6.38-7.98 the average difference in pH readings in the two media was 0.04 pH units. In summary, we have demonstrated that these optical sensors agree well with standard electrochemical probes. The accuracy of the optical probes demonstrates their ability to detect potential parameter drift that could have significant impact on growth, production kinetics, and protein product quality. We have also shown that an increase in osmolality that could result from controlling pH or operating the reactor in fed-batch mode has an insignificant impact on the functionality of the pH patches. PMID:17216654

Hanson, Michael A; Ge, Xudong; Kostov, Yordan; Brorson, Kurt A; Moreira, Antonio R; Rao, Govind

2007-07-01

392

Apoptotic cells subjected to cold/warming exposure disorganize apoptotic microtubule network and undergo secondary necrosis.  

PubMed

Apoptotic microtubule network (AMN) is organized during apoptosis, forming a cortical structure beneath the plasma membrane which plays a critical role in preserving cell morphology and plasma membrane integrity. The aim of this study was to examine the effect of cold/warming exposure on apoptotic microtubules and plasma membrane integrity during the execution phase of apoptosis. We demonstrated in camptothecin-induced apoptotic H460 cells that cold/warming exposure disorganized apoptotic microtubules and allowed the access of active caspases to the cellular cortex and the cleavage of essential proteins in the preservation of plasma membrane permeability. Cleavage of cellular cortex and plasma membrane proteins, such as ?-spectrin, paxilin, focal adhesion kinase and calcium ATPase pump (PMCA-4) involved in cell calcium extrusion resulted in increased plasma permeability and calcium overload leading apoptotic cells to secondary necrosis. The essential role of caspase-mediated cleavage in this process was demonstrated because the addition of the pan-caspase inhibitor z-VAD during cold/warming exposure that induces AMN depolymerization avoided the cleavage of cortical and plasma membrane proteins and prevented apoptotic cells to undergo secondary necrosis. Likewise, apoptotic microtubules stabilization by taxol during cold/warming exposure also prevented cellular cortex and plasma membrane protein cleavage and secondary necrosis. Furthermore, microtubules stabilization or caspase inhibition during cold/warming exposure was also critical for proper phosphatidylserine externalization and apoptotic cell clearance by macrophages. These results indicate that cold/warming exposure of apoptotic cells induces secondary necrosis which can be prevented by both, microtubule stabilization or caspase inhibition. PMID:25027509

Oropesa-Ávila, Manuel; Fernández-Vega, Alejandro; de la Mata, Mario; Garrido-Maraver, Juan; Cotán, David; Paz, Marina Villanueva; Pavón, Ana Delgado; Cordero, Mario D; Alcocer-Gómez, Elizabet; de Lavera, Isabel; Lema, Rafael; Zaderenko, Ana Paula; Sánchez-Alcázar, José A

2014-09-01

393

Characterization of high-power lithium-ion cells during constant current cycling. Part I. Cycle performance and electrochemical diagnostics  

SciTech Connect

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.

Shim, Joongpyo; Striebel, Kathryn A.

2003-01-24

394

Electrochemical treatment of waste  

SciTech Connect

Electrochemical processes are being developed to treat hazardous and radioactive wastes. In these processes, heavy metals are removed from solution and recovered while cyanides and toxic organic compounds are oxidized to carbon dioxide. Destruction of the organic components is either done directly at the anode or through mediated electron transfer using electrochemically generated cobalt (III) or silver (II). Applying innovative electrochemical techniques bench-scale studies have shown that the concentration of selected toxic metals can be reduced to less than 100 ppb in the waste streams. Electrochemical treatment processes are effective alternatives to other chemical or thermal treatment processes. They require little or no reagent addition, operate at ambient or slightly elevated temperatures, allow for selective recovery of metal ions, and greatly decrease the volume of secondary waste.

Dziewinski, J.; Marczak, S.; Purdy, G. [Los Alamos National Lab., NM (United States)] [and others

1995-12-31

395

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

SciTech Connect

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})

Shen, Yanbin; Pedersen, Erik E.; Christensen, Mogens; Iversen, Bo B., E-mail: bo@chem.au.dk [Center for Materials Crystallography, Department of Chemistry and iNANO, Aarhus University, Aarhus (Denmark)

2014-10-15

396

Aging Studies of Sr-doped LaCrO3/YSZ/Pt Cells for an Electrochemical NOx Sensor  

SciTech Connect

The stability and NO{sub x} sensing performance of electrochemical cells of the structure Sr-doped LaCrO{sub 3-{delta}} (LSC)/yttria-stabilized zirconia (YSZ)/Pt are being investigated for use in NO{sub x} aftertreatment systems in diesel vehicles. Among the requirements for NO{sub x} sensor materials in these systems are stability and long lifetime (up to ten years) in the exhaust environment. In this study, cell aging effects were explored following extended exposure to a test environment of 10% O{sub 2} at operating temperatures of 600-700 C. The data show that aging results in changes in particle morphology, chemical composition and interfacial structure, Impedance spectroscopy indicated an initial increase in the cell resistance during the early stages of aging, which is correlated to densification of the Pt electrode. Also, x-ray photoelectron spectroscopy indicated formation of SrZrO{sub 2} solid state reaction product in the LSC, a process which is of finite duration. Subsequently, the overall cell resistance decreases with aging time due, in part, to roughening of YSZ-LSC interface, which improves interface adherence and enhances charge transfer kinetics at the O{sub 2}/YSZ/LSC triple phase boundary. This study constitutes a first step in the development of a basic understanding of aging phenomena in solid state electrochemical systems with application not only to sensors, but also to fuel cells, membranes, and electrolyzers.

Song, S; Martin, L P; Glass, R S; Murray, E P; Visser, J H; Soltis, R E; Novak, R F; Kubinski, D J

2005-10-05

397

Tapia's syndrome secondary to laterocervical localization of diffuse large cell lymphoma.  

PubMed

The eponym "Tapia's syndrome" indicates an associated unilateral vocal cord and tongue paralysis secondary to a peripheral involvement of the recurrent laryngeal branch and the hypoglossal nerve. Although mainly observed as a complication of surgery or anaesthesia, it can rarely occur secondary to infectious or neoplastic causes. We are presenting a case of a teen-ager with Tapia's syndrome who had been seeking medical assistance for episodes of loss of consciousness and was diagnosed with a high-grade peripheral B-cell lymphoma, an association not previously described. This syndrome should be remembered even outside the surgical contest for its highly localising value. PMID:23958591

Cantalupo, Gaetano; Spagnoli, Carlotta; Cerasti, Davide; Piccolo, Benedetta; Crisi, Girolamo; Pisani, Francesco

2014-06-01

398

Electrochemical valorisation of glycerol.  

PubMed

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

Simões, Mário; Baranton, Stève; Coutanceau, Christophe

2012-11-01

399

Fusion of bone marrow-derived cells with cancer cells: metastasis as a secondary disease in cancer  

PubMed Central

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

Pawelek, John M.

2014-01-01

400

Secondary monoclonal gammopathy of undetermined significance after allogeneic stem cell transplantation in multiple myeloma  

PubMed Central

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

Schmitz, Marian F.; Otten, Henny G.; Franssen, Laurens E.; van Dorp, Suzanne; Strooisma, Theo; Lokhorst, Henk M.; van de Donk, Niels W.C.J.

2014-01-01

401

Electrochemical struvite precipitation from digestate with a fluidized bed cathode microbial electrolysis cell.  

PubMed

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

Cusick, Roland D; Ullery, Mark L; Dempsey, Brian A; Logan, Bruce E

2014-05-01

402

Electrochemical concentration cell ozone soundings at two sites during the Stratospheric Ozone Intercomparison Campaign  

NASA Astrophysics Data System (ADS)

The Stratospheric Ozone Intercomparison Campaign (STOIC) was designed to compare proposed instruments for the Network for the Detection of Stratospheric Change (NDSC) with established measurement techniques. Ground-based measurements were conducted at Table Mountain, California (34.4°N, 117.7°W), and rocket profiles were made at San Nicolas Island, California (33.3°N, 119.5°W). In an effort to estimate site-to-site differences during the intercomparison, daily soundings were made with balloon-borne electrochemical concentration cell (ECC) ozonesondes at the two sites. Comparisons have been made of the mean values for the soundings at each site. The soundings showed small temperature differences between the two sites with the nighttime Table Mountain measurements up to 2°K cooler than the daytime San Nicolas Island temperatures. Day/night temperature corrections based on the emissivity and absorptivity of the thermistors in the balloon instruments can account for these apparent temperature differences. Ozone partial pressure profiles from the ECCs have been used to estimate atmospheric ozone variability during STOIC. Above 20 km, the lowest altitude for the STOIC comparisons, the average data sets from both sites showed standard deviations that were at or below the estimated 5-6% profile-to-profile repeatability for the ozonesondes. This indicates that atmospheric ozone variability was only of the order of a few percent above 20 km during the 2 weeks of the STOIC campaign. Above 20 km the ozone partial pressures over the Table Mountain site averaged 2.0% lower than over San Nicolas Island.

Barnes, Robert A.; Torres, Arnold L.

1995-05-01

403

Enrichment of microbial community generating electricity using a fuel-cell-type electrochemical cell  

Microsoft Academic Search

A fuel cell was used to enrich a microbial consortium generating electricity, using organic wastewater as the fuel. Within 30 days of enrichment the maximum current of 0.2 mA was generated with a resistance of 1 kO. Current generation was coupled to a fall in chemical oxygen demand from over 1,700 mg l -1 down to 50 mg l -1. Denaturing gradient gel electrophoresis showed a

B. H. Kim; H. S. Park; H. J. Kim; G. T. Kim; I. S. Chang; J. Lee; N. T. Phung

2004-01-01

404

Novel Management of Acute or Secondary Biliary Liver Conditions Using Hepatically Differentiated Human Dental Pulp Cells  

PubMed Central

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

Ishkitiev, Nikolay; Imai, Toshio; Tanaka, Tomoko; Fushimi, Naho; Mitev, Vanyo; Okada, Mio; Tominaga, Noriko; Ono, Sachie; Ishikawa, Hiroshi

2015-01-01

405

Viral particles drive rapid differentiation of memory B cells into secondary plasma cells producing increased levels of antibodies.  

PubMed

Extensive studies have been undertaken to describe naive B cells differentiating into memory B cells at a cellular and molecular level. However, relatively little is known about the fate of memory B cells upon Ag re-encounter. We have previously established a system based on virus-like particles (VLPs), which allows tracking of VLP-specific B cells by flow cytometry as well as histology. Using allotype markers, it is possible to adoptively transfer memory B cells into a naive mouse and track responses of naive and memory B cells in the same mouse under physiological conditions. We have observed that VLP-specific memory B cells quickly differentiated into plasma cells that drove the early onset of a strong humoral IgG response. However, neither IgM(+) nor IgG(+) memory B cells proliferated extensively or entered germinal centers. Remarkably, plasma cells derived from memory B cells preferentially homed to the bone marrow earlier and secreted increased levels of Abs when compared with primary plasma cells derived from naive B cells. Hence, memory B cells have the unique phenotype to differentiate into highly effective secondary plasma cells. PMID:24821969

Zabel, Franziska; Mohanan, Deepa; Bessa, Juliana; Link, Alexander; Fettelschoss, Antonia; Saudan, Philippe; Kündig, Thomas M; Bachmann, Martin F

2014-06-15

406

A novel approach for analyzing electrochemical properties of mixed conducting solid oxide fuel cell anode materials by impedance spectroscopy.  

PubMed

For application of acceptor-doped mixed conducting oxides as solid oxide fuel cell (SOFC) anodes, high electrochemical surface activity as well as acceptable electronic and ionic conductivity are crucial. In a reducing atmosphere, particularly the electronic conductivity of acceptor-doped oxides can become rather low and the resulting complex interplay of electrochemical reactions and charge transport processes makes a mechanistic interpretation of impedance measurements very complicated. In order to determine all relevant resistive and capacitive contributions of mixed conducting electrodes in a reducing atmosphere, a novel electrode design and impedance-based analysis technique is therefore introduced. Two interdigitating metallic current collectors are placed in a microelectrode, which allows in-plane measurements within the electrode as well as electrochemical measurements versus a counter electrode. Equivalent circuit models for quantifying the spectra of both measurement modes are developed and applied to simultaneously fit both spectra, using the same parameter set. In this manner, the electronic and ionic conductivity of the material as well as the area-specific resistance of the surface reaction and the chemical capacitance can be determined on a single microelectrode in a H2-H2O atmosphere. The applicability of this new tool was demonstrated in SrTi0.7Fe0.3O(3-?) (STFO) thin film microelectrodes, deposited on single-crystalline yttria-stabilized zirconia (YSZ) substrates. All materials parameters that contribute to the polarization resistance of STFO electrodes in a reducing atmosphere could thus be quantified. PMID:25219525

Nenning, A; Opitz, A K; Huber, T M; Fleig, J

2014-10-28

407

Characterization of local electrochemical doping of high performance conjugated polymer for photovoltaics using scanning droplet cell microscopy?  

PubMed Central

The electrochemical oxidation of a next generation low bandgap high performance photovoltaic material namely poly[4,8-bis-substituted-benzo[1,2-b:4,5-b0]dithiophene-2,6-diyl-alt-4-substituted-thieno[3,4-b] thiophene-2,6-diyl] (PBDTTT-c) thin film was investigated using a scanning droplet cell microscope. Cyclic voltammetry was used for the basic characterization of the oxidation/doping of PBDTTT-c. Application of the different final potentials during the electrochemical study provides a close look to the oxidation kinetics. The electrical properties of both doped and undoped PBDTTT-c were analyzed in situ by electrochemical impedance spectroscopy giving the possibility to correlate the changes in the doping level with the subsequent changes in the resistance and capacitance. As a result one oxidation peak was found during the cyclic voltammetry and in potentiostatic measurements. From Mott–Schottky analysis a donor concentration of 2.3 × 1020 cm?3 and a flat band potential of 1.00 V vs. SHE were found. The oxidation process resulted in an increase of the conductivity by two orders of magnitude reaching a maximum for the oxidized form of 1.4 S cm?1.

Gasiorowski, Jacek; Mardare, Andrei Ionut; Sariciftci, Niyazi Serdar; Hassel, Achim Walter

2013-01-01

408

Use of High Temperature Electrochemical Cells for Co-Generation of Chemicals and Electricity  

SciTech Connect

In this project, two key issues were addressed to show the feasibility of electrochemical partial oxidation (EPOx) in a SOFC. First, it was demonstrated that SOFCs can reliably operate directly with natural gas. These results are relevant to both direct-natural-gas SOFCs, where the aim is solely electrical power generation, and to EPOx. Second, it must be shown that SOFCs can work effectively as partial oxidation reactors, i.e, that they can provide high conversion efficiency of natural gas to syngas. The results of this study in both these areas look extremely promising. The main results are summarized briefly: (1) Stability and coke-free direct-methane SOFC operation is promoted by the addition of a thin porous inert barrier layer to the anode and the addition of small amounts of CO{sub 2} or air to the fuel stream; (2) Modeling results readily explained these improvements by a change in the gas composition at the Ni-YSZ anode to a non-coking condition; (3) The operation range for coke-free operation is greatly increased by using a cell geometry with a thin Ni-YSZ anode active layer on an inert porous ceramic support, i.e., (Sr,La)TiO{sub 3} or partially-stabilized zirconia (in segmented-in-series arrays); (4) Ethane and propane components in natural gas greatly increase coking both on the SOFC anode and on gas-feed tubes, but this can be mitigated by preferentially oxidizing these components prior to introduction into the fuel cell, the addition of a small amount of air to the fuel, and/or the use of ceramic-supported SOFC; (5) While a minimum SOFC current density was generally required to prevent coking, current interruptions of up to 8 minutes yielded only slight anode coking that caused no permanent damage and was completely reversible when the cell current was resumed; (6) Stable direct-methane SOFC operation was demonstrated under EPOx conditions in a 350 h test; (7) EPOx operation was demonstrated at 750 C that yielded 0.9 W/cm{sup 2} and a syngas production rate of 30 sccm/cm{sup 2}, and the reaction product composition was close to the equilibrium prediction during the early stages of cell testing; (8) The methane conversion to syngas continuously decreased during the first 100 h of cell testing, even though the cell electrical characteristics did not change, due to a steady decrease in the reforming activity of Ni-YSZ anodes; (9) The stability of methane conversion was substantially improved via the addition of a more stable reforming catalyst to the SOFC anode; (10) Modeling results indicated that a SOFC with anode barrier provides similar non-coking performance as an internal reforming SOFC, and provides a simpler approach with no need for a high-temperature exhaust-gas recycle pump; (11) Since there is little or no heat produced in the EPOx reaction, overall efficiency of the SOFC operated in this mode can, in theory, approach 100%; and (12) The combined value of the electricity and syngas produced allows the EPOx generator to be economically viable at a >2x higher cost/kW than a conventional SOFC.

Scott Barnett

2007-09-30

409

Mechanistic studies of water electrolysis and hydrogen electro-oxidation on high temperature ceria-based solid oxide electrochemical cells.  

PubMed

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

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

410

3D CFD Electrochemical and Heat Transfer Model of an Integrated-Planar Solid Oxide Electrolysis Cells  

SciTech Connect

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.

Grant Hawkes; James E. O'Brien

2008-10-01

411

Large-Scale Co-Expression Approach to Dissect Secondary Cell Wall Formation Across Plant Species  

PubMed Central

Plant cell walls are complex composites largely consisting of carbohydrate-based polymers, and are generally divided into primary and secondary walls based on content and characteristics. Cellulose microfibrils constitute a major component of both primary and secondary cell walls and are synthesized at the plasma membrane by cellulose synthase (CESA) complexes. Several studies in Arabidopsis have demonstrated the power of co-expression analyses to identify new genes associated with secondary wall cellulose biosynthesis. However, across-species comparative co-expression analyses remain largely unexplored. Here, we compared co-expressed gene vicinity networks of primary and secondary wall CESAsin Arabidopsis, barley, rice, poplar, soybean, Medicago, and wheat, and identified gene families that are consistently co-regulated with cellulose biosynthesis. In addition to the expected polysaccharide acting enzymes, we also found many gene families associated with cytoskeleton, signaling, transcriptional regulation, oxidation, and protein degradation. Based on these analyses, we selected and biochemically analyzed T-DNA insertion lines corresponding to approximately twenty genes from gene families that re-occur in the co-expressed gene vicinity networks of secondary wall CESAs across the seven species. We developed a statistical pipeline using principal component analysis and optimal clustering based on silhouette width to analyze sugar profiles. One of the mutants, corresponding to a pinoresinol reductase gene, displayed disturbed xylem morphology and held lower levels of lignin molecules. We propose that this type of large-scale co-expression approach, coupled with statistical analysis of the cell wall contents, will be useful to facilitate rapid knowledge transfer across plant species. PMID:22639584

Ruprecht, Colin; Mutwil, Marek; Saxe, Friederike; Eder, Michaela; Nikoloski, Zoran; Persson, Staffan

2011-01-01

412

Alternating-polarity operation for complete regeneration of electrochemical deionization system  

DOEpatents

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.

Tran, Tri D. (Livermore, CA); Lenz, David J. (Livermore, CA)

2002-01-01

413

Host response. Inflammation-induced disruption of SCS macrophages impairs B cell responses to secondary infection.  

PubMed

The layer of macrophages at the subcapsular sinus (SCS) captures pathogens entering the lymph node, preventing their global dissemination and triggering an immune response. However, how infection affects SCS macrophages remains largely unexplored. Here we show that infection and inflammation disrupt the organization of SCS macrophages in a manner that involves the migration of mature dendritic cells to the lymph node. This disrupted organization reduces the capacity of SCS macrophages to retain and present antigen in a subsequent secondary infection, resulting in diminished B cell responses. Thus, the SCS macrophage layer may act as a sensor or valve during infection to temporarily shut down the lymph node to further antigenic challenge. This shutdown may increase an organism's susceptibility to secondary infections. PMID:25657250

Gaya, Mauro; Castello, Angelo; Montaner, Beatriz; Rogers, Neil; Reis e Sousa, Caetano; Bruckbauer, Andreas; Batista, Facundo D

2015-02-01

414

Increases of secondary metabolite production in various plant cell cultures by co-cultivation with cork.  

PubMed

Cork tissues increased secondary metabolite production of various plant cell cultures in a different manner from those of conventional elicitors. In Sophora flavescens and Glycyrrhiza glabra cultured cells, cork tissues increased the amounts of both lipophilic and hydrophilic flavonoids without affecting the cell growth, although elicitors such as copper ion and yeast extracts showed a clear inhibition of cell growth with the increasing amount of these lipophilic ones. The validity of this effect of cork tissues covered a wide range of aromatic compounds produced by suspension cell cultures derived from diverse plant species. Woody tissues of Japanese cypress had a very similar effect to that of cork. Partial purification of cork tissues suggested that the production-stimulating factor was present in the hemicellulose B fraction that was not included in the dedifferentiated cultured tissues. PMID:11388464

Yamamoto, H; Yato, A; Yazaki, K; Hayashi, H; Taguchi, G; Inoue, K

2001-04-01

415

Comparison of Morphology, Orientation, and Migration of Tendon Derived Fibroblasts and Bone Marrow Stromal Cells on Electrochemically Aligned Collagen Constructs  

PubMed Central

There are approximately 33 million injuries involving musculoskeletal tissues (including tendons and ligaments) every year in the United States. In certain cases the tendons and ligaments are damaged irreversibly and require replacements that possess the natural functional properties of these tissues. As a biomaterial, collagen has been a key ingredient in tissue engineering scaffolds. The application range of collagen in tissue engineering would be greatly broadened if the assembly process could be better controlled to facilitate the synthesis of dense, oriented tissue-like constructs. An electrochemical method has recently been developed in our laboratory to form highly oriented and densely packed collagen bundles with mechanical strength approaching that of tendons. However, there is limited information whether this electrochemically aligned collagen bundle (ELAC) presents advantages over randomly oriented bundles in terms of cell response. Therefore, the current study aimed to assess the biocompatibility of the collagen bundles in vitro, and compare tendon derived fibroblasts (TDFs) and bone marrow stromal cells (MSCs) in terms of their ability to populate and migrate on the single and braided ELAC bundles. The results indicated that the ELAC was not cytotoxic; both cell types were able to populate and migrate on the ELAC bundles more efficiently than that observed for random collagen bundles. The braided ELAC constructs were efficiently populated by both TDFs and MSCs in vitro. Therefore, both TDFs and MSCs can be used with the ELAC bundles for tissue engineering purposes. PMID:20694974

Gurkan, Umut Atakan; Cheng, Xingguo; Kishore, Vipuil; Uquillas, Jorge Alfredo; Akkus, Ozan

2010-01-01

416

Determination of penetratin secondary structure in live cells with Raman microscopy.  

PubMed

Cell penetrating peptides (CPPs) have attracted recent interest as drug delivery tools, although the mechanisms by which CPPs are internalized by cells are not well-defined. Here, we report a new experimental approach for the detection and secondary structure determination of CPPs in live cells using Raman microscopy with heavy isotope labeling of the peptide. As a first demonstration of principle, penetratin, a 16-residue CPP derived from the Antennapedia homeodomain protein of Drosophila, was measured in single, living melanoma cells. Carbon-13 labeling of the Phe residue of penetratin was used to shift the intense aromatic ring-breathing vibrational mode from 1003 to 967 cm(-1), thereby enabling the peptide to be traced in cells. Difference spectroscopy and principal components analysis (PCA) were used independently to resolve the Raman spectrum of the peptide from the background cellular Raman signals. On the basis of the position of the amide I vibrational band in the Raman spectra, the secondary structure of the peptide was found to be mainly random coil and beta-strand in the cytoplasm, and possibly assembling as beta-sheets in the nucleus. The rapid entry and almost uniform cellular distribution of the peptide, as well as the lack of correlation between peptide and lipid Raman signatures, indicated that the mechanism of internalization under the conditions of study was probably nonendocytotic. This experimental approach can be used to study a wide variety of CPPs as well as other classes of peptides in living cells. PMID:20041639

Ye, Jing; Fox, Sara A; Cudic, Mare; Rezler, Evonne M; Lauer, Janelle L; Fields, Gregg B; Terentis, Andrew C

2010-01-27

417

The role of the secondary cell wall in plant resistance to pathogens  

PubMed Central

Plant resistance to pathogens relies on a complex network of constitutive and inducible defensive barriers. The plant cell wall is one of the barriers that pathogens need to overcome to successfully colonize plant tissues. The traditional view of the plant cell wall as a passive barrier has evolved to a concept that considers the wall as a dynamic structure that regulates both constitutive and inducible defense mechanisms, and as a source of signaling molecules that trigger immune responses. The secondary cell walls of plants also represent a carbon-neutral feedstock (lignocellulosic biomass) for the production of biofuels and biomaterials. Therefore, engineering plants with improved secondary cell wall characteristics is an interesting strategy to ease the processing of lignocellulosic biomass in the biorefinery. However, modification of the integrity of the cell wall by impairment of proteins required for its biosynthesis or remodeling may impact the plants resistance to pathogens. This review summarizes our understanding of the role of the plant cell wall in pathogen resistance with a focus on the contribution of lignin to this biological process. PMID:25161657

Miedes, Eva; Vanholme, Ruben; Boerjan, Wout; Molina, Antonio

2014-01-01

418

Characterization of Damp-Heat Degradation of CuInGaSe2 Solar Cell Components and Devices by (Electrochemical) Impedance Spectroscopy: Preprint  

SciTech Connect

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.

Pern, F. J. J.; Noufi, R.

2011-09-01

419

Process for manufacture of positive electrode for lithium/metal sulfide secondary cell  

SciTech Connect

An electrode for a high temperature secondary electrical storage cell including an alkali metal negative electrode, a molten salt electrolyte, and a transition metal sulfide as the positive electrode, formed by mechanically loading a precut form or graphite felt or foam with fesx powder, coating or impregnating the precut form with a high carbon yield resin, curing the resin at an intermediate temperature, and carbonizing the resin at a temperature below 1000/sup 0/C.

Joo, L.A.; Miller, F.C.

1980-11-11

420

Electrochemical Filtering of CO from Fuel-Cell Reformate Balasubramanian Lakshmanan,a,  

E-print Network

as a fuel in automotive and residential applications has many limi- tations. The infrastructure to deliver H reaction. The fuel exiting the LTS is then fed to a preferential partial oxidizer PrOx , wherein the CO system may be replaced. Namely, an electrochemical filter EF for CO using current PEMFC technol- ogy

Weidner, John W.

421

Rigid and flexible organic electrochemical transistor arrays for monitoring action potentials from electrogenic cells.  

PubMed

Rigid and flexible organic electrochemical transistor arrays are successfully implemented for monitoring cardiac action potentials. Excellent signal to noise ratios are achieved with values routinely larger than 4. These devices are promising to be used in both conventional and emerging areas. PMID:25358525

Yao, Chunlei; Li, Qianqian; Guo, Jing; Yan, Feng; Hsing, I-Ming

2015-03-01

422

The dynamic behavior of thin-film ionic transition metal complex-based light-emitting electrochemical cells  

NASA Astrophysics Data System (ADS)

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.

Meier, Sebastian B.; Hartmann, David; Winnacker, Albrecht; Sarfert, Wiebke

2014-09-01

423

The dynamic behavior of thin-film ionic transition metal complex-based light-emitting electrochemical cells  

SciTech Connect

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){sub 2}(pbpy)][PF{sub 6}]). 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.

Meier, Sebastian B., E-mail: sebastian.meier@belectric.com, E-mail: wiebke.sarfert@siemens.com [Department of Materials Science VI: Materials for Electronics and Energy Technology, Friedrich-Alexander-University of Erlangen-Nuremberg, 91058 Erlangen (Germany); Siemens AG, Corporate Technology, CT RTC MAT IEC-DE, 91058 Erlangen (Germany); Hartmann, David; Sarfert, Wiebke, E-mail: sebastian.meier@belectric.com, E-mail: wiebke.sarfert@siemens.com [Siemens AG, Corporate Technology, CT RTC MAT IEC-DE, 91058 Erlangen (Germany); Winnacker, Albrecht [Department of Materials Science VI: Materials for Electronics and Energy Technology, Friedrich-Alexander-University of Erlangen-Nuremberg, 91058 Erlangen (Germany)

2014-09-14

424

Toxicological characterization of the landfill leachate prior/after chemical and electrochemical treatment: a study on human and plant cells.  

PubMed

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

Garaj-Vrhovac, Vera; Oreš?anin, Višnja; Gajski, Goran; Geri?, Marko; Ruk, Damir; Kollar, Robert; Radi? Brkanac, Sandra; Cvjetko, Petra

2013-10-01

425

Growth and differentiation of permanent and secondary mouse myogenic cell lines on microcarriers.  

PubMed

Myogenesis involves the determination of progenitor cells to myoblasts, their fusion to yield multinuclear myotubes, and the maturation of myotubes to muscle fibres. This development is reflected in a time pattern of gene expression, e.g. of genes coding for desmin, the myogenic factors myogenin and myoD, the acetylcholine receptor alpha-subunit and the muscular chloride channel CIC-1. We attempted to improve yields and myogenic differentiation in culture by using three-dimensional microcarrier systems. Out of a variety of carriers tested in stationary cultures, collagen-coated dextran Cytodex3 beads proved optimal for the proliferation and differentiation of the murine myogenic cell line C2C12. With C2C12 myoblasts in stationary and stirred systems (Spinner- and SuperSpinner flasks), surface adherence, differentiation into myotubes and expression of muscle-specific mRNAs on Cytodex3 beads were the same as in conventional cultures. Other carriers tested (DEAE cellulose, glass, plastic, cellulose, polyester) did not support growth and differentiation of C2C12 cells. The secondary mouse myogenic stem cells M12 and M2.7-MDX proliferated and differentiated well in stationary Cytodex3 cultures, but no differentiation occurred in Spinner flasks. As indicated by light and scanning electron microscopy, C2C12 myotubes formed not only on but also in between Cytodex beads. The secondary cell lines may succumb to shear forces under these conditions. PMID:11414320

Bardouille, C; Lehmann, J; Heimann, P; Jockusch, H

2001-05-01

426

Altered Secondary Myogenesis in Transgenic Animals Expressing the Neural Cell Adhesion Molecule under the Control of a Skeletal Muscle ot-Actin Promoter  

Microsoft Academic Search

The majority of skeletal muscle fibers are generated through the process of secondary myogene- sis. Cell adhesion molecules such as NCAM are thought to be intricately involved in the cell-cell interactions between developing secondary and primary myotubes. During secondary myogenesis, the expression of NCAM in skeletal muscle is under strict spatial and temporal control. To investigate the role of NCAM

Sam Fazeli; Dominic J. Wells; Carl Hobbs; Frank S. Walsh

1996-01-01

427

Abundance of mixed linkage glucan in mature tissues and secondary cell walls of grasses  

PubMed Central

(1,3; 1,4)-?-D-glucan, also known as mixed linkage glucan (MLG), is a polysaccharide that in flowering plants is unique to the cell walls of grasses and other related members of Poales. MLG is highly abundant in endosperm cell walls, where it is considered a storage carbohydrate. In vegetative tissues, MLG transiently accumulates in the primary cell walls of young, elongating organs. In evolutionary distant species such as Equisetum, MLG accumulates predominantly in old tissues in the stems. Similarly, we have recently shown that rice accumulates a large amount of MLG in mature stems, which prompted us to re-evaluate the hypothesis that MLG is solely related to growth in grass vegetative tissues. Here, we summarize data that confirms the presence of MLG in secondary cell walls and mature tissues in rice and other grasses. Along with these results, we discuss additional evidence indicating a broader role for MLG than previously considered. PMID:23299432

Vega-Sánchez, Miguel E.; Verhertbruggen, Yves; Scheller, Henrik V.; Ronald, Pamela C.

2013-01-01

428

Effects of proton-exchange membrane fuel-cell operating conditions on charge transfer resistances measured by electrochemical impedance spectroscopy  

SciTech Connect

Proton-exchange-membrane fuel cells (PEMFC) are highly dependent on operating conditions, such as humidity and temperature. This study employs electrochemical impedance spectroscopy (EIS) to measure the effects of operating parameters on internal proton and electron transport resistance mechanisms in the PEMFC. Current-density experiments have been performed to measure the power production in a 25 cm{sup 2} Nafion 117 PEMFC at varying operating conditions. These experiments have shown that low humidity and low temperature contribute to decreased power production. EIS is currently employed to provide a better understanding of the mechanisms involved in power production by calculating the specific resistances at various regions in the PEMFC. Experiments are performed at temperatures ranging from 30 to 50 C, feed humidities from 20 to 98%, and air stoichiometric ratios from 1.33 to 2.67. In all experiments, the hydrogen feed stoichiometric ratio was approximately 4.0. EIS is used to identify which transport steps limit the power production of the PEMFC over these ranges of conditions. The experimental data are analyzed via comparison to equivalent circuit models (ECMs), a technique that uses an electrical circuit to represent the electrochemical and transport properties of the PEMFC. These studies will aid in designing fuel cells that are more tolerant to wide-ranging operating conditions. In addition, optimal operating conditions for PEMFC operation can be identified.

Aaron, Doug S [ORNL; Yiacoumi, Sotira [Georgia Institute of Technology; Tsouris, Costas [ORNL

2008-01-01

429

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

E-print Network

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

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

2011-01-01

430

Formation of surface morphology of silicon solar cells by means of two-step photo-electrochemical etching and their characterization  

NASA Astrophysics Data System (ADS)

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.

Shatkovskis, E.; Zagadskij, V.; Jukna, A.; Boris, R.; Antonovic, V.; Stupakova, J.; Mitkevicius, R.; Baradinskaite, A.; Keriene, J.

2014-10-01

431

Prevention of secondary stroke and resolution of transfusional iron overload in children with sickle cell anemia using hydroxyurea and phlebotomy  

Microsoft Academic Search

ObjectiveTransfusions prevent secondary stroke in children with sickle cell anemia (SCA) but also cause iron overload. Alternatives for stroke prophylaxis with effective therapy to reduce iron burden are needed.

Russell E. Ware; Sherri A. Zimmerman; Pamela B. Sylvestre; Nicole A. Mortier; Jacqueline S. Davis; William R. Treem; William H. Schultz

2004-01-01

432

Magnetic Properties of Cobalt-Cluster Dispersions Generated in AN Electrochemical Cell  

Microsoft Academic Search

Magnetization curves of stabilized cobalt-cluster dispersions in tetrahydrofuran with a narrow size distribution have been studied by SQUID and Gouy balance measurements. The cobalt colloids are generated by a newly developed electrochemical method which allows one to generate clusters with mean cluster sizes of about 1000 atoms. The final size distribution of the clusters is examined by small-angle x-ray scattering

J. A. Becker; R. Schäfer; J. R. Festag; J. H. Wendorff; F. Hensel; J. Pebler; S. A. Quaiser; W. Helbig; M. T. Reetz

1996-01-01

433

Anionic membrane based on polyepichlorhydrin matrix for alkaline fuel cell: Synthesis, physical and electrochemical properties  

Microsoft Academic Search

Polymer electrolytes, using a poly(epichlorydrin-allyl glycidyl ether) copolymer as matrix, were prepared and characterized. Anion conducting networks were obtained by the incorporation of two cyclic diamines named 1,4-diazabicyclo-[2.2.2]-octane (DABCO) and 1-azabicyclo-[2.2.2]-octane (Quinuclidine), neither sensitive to Hoffman elimination. In order to improve the mechanical properties, the membrane was reinforced using polyamide supports. The physicochemical and electrochemical characteristics, namely ionic exchange capacity,

D. Stoica; L. Ogier; L. Akrour; F. Alloin; J. F. Fauvarque

2007-01-01

434

Electrochemical reduction of dichlorodifluoromethane at a Nafion® solid polymer electrolyte cell  

Microsoft Academic Search

The electrochemical reduction of dichlorodifluoromethane (CFC-12) at Ag, Pd, Cu and Au electrodes (which were deposited on Nafion® 117 (H+ form) membranes, by reduction with NaBH4 (10% w\\/v) solution) was studied. The products of the reduction were CHClF2, CH2F2, CH3F and CH4, as well as small amounts of dimers, CF2?CF2 and CHF2CHF2. The silver electrode gave the highest current efficiency

Th. Fotiadis; G. Kyriacou; Ch. Lambrou; S. Hadjispyrou

2000-01-01

435

The overall structure of the human lens is one of succes-sive generations of secondary fiber cells stratified chrono-  

E-print Network

The overall structure of the human lens is one of succes- sive generations of secondary fiber cells Department of Cell Biology and Human Anatomy, School of Medicine, University of California, Davis, CA; 4 Purpose: Human eye lenses contain cells that persist from embryonic development. These unique, highly

Hammock, Bruce D.

436

Characterisation of a electrochemical hydrogen pump using electrochemical impedance spectroscopy  

Microsoft Academic Search

Electrochemical hydrogen pumps are electrochemical devices which are used for hydrogen purification and pressurization purposes.\\u000a In such cells, gaseous hydrogen is oxidized at the anode and released at the cathode. Results presented in this paper are\\u000a related to the characterization and optimization of a proton-exchange membrane (PEM) hydrogen pump using electrochemical impedance\\u000a spectroscopy (EIS). Only the case of hydrogen purification

M.-T. Nguyen; S. A. Grigoriev; A. A. Kalinnikov; A. A. Filippov; P. Millet; V. N. Fateev

437

A time course study of cadmium effect on membrane permeability of single human bladder cancer cells using scanning electrochemical microscopy.  

PubMed

Cd(2+) is carcinogenic to both humans and experimental animals. We present quantitative time-course imaging of Cd(2+)-induced variation in the membrane permeability of single live human bladder cancer cells (T24) to ferrocenemethanol using scanning electrochemical microscopy (SECM). High temporal resolution combined with non-invasive nature renders a time-lapse SECM depth scan, a promising method to quantitatively investigate the effectiveness, kinetics, and mechanism of metal ions based on the responses of single live cells in real time. Under unstimulated conditions, T24 cells have constant membrane permeability to ferrocenemethanol of approximately 5.0×10(-5) m/s. When cadmium is added in-situ to T24 cells, the membrane permeability increases up to 3.5×10(-4) m/s, allowing more flux of ferrocenemethanol to the ultramicroelectrode tip. This suggests an increased spreading between the phospholipid heads in the cytoplasmic membrane. Membrane permeability might be used as a measure to probe cell status in practical intoxication cases. The methodology reported here can be applied to many other metals and their interactions with extracellular biomolecules, leading insights into cell physiology and pathobiology. PMID:24656893

Li, Michelle S M; Filice, Fraser P; Ding, Zhifeng

2014-07-01

438

Half-cell potential analysis of an ammonia sensor with the electrochemical cell Au | YSZ | Au, V2O5-WO3-TiO2.  

PubMed

Half-cell potentials of the electrochemical cell Au, VWT | YSZ | Au are analyzed in dependence on oxygen and ammonia concentration at 550 °C. One of the gold electrodes is covered with a porous SCR catalyst, vanadia-tungstenia-titania (VWT). The cell is utilized as a potentiometric ammonia gas sensor and provides a semi-logarithmic characteristic curve with a high NH3 sensitivity and selectivity. The analyses of the Au | YSZ and Au, VWT | YSZ half-cells are conducted to describe the non-equilibrium behavior of the sensor device in light of mixed potential theory. Both electrode potentials provide a dependency on the NH3 concentration, whereby VWT, Au | YSZ shows a stronger effect which increases with increasing VWT coverage. The potential shifts in the anodic direction confirm the formation of mixed potentials at both electrodes resulting from electrochemical reactions of O2 and NH3 at the three-phase boundary. Polarization curves indicate Butler-Volmer-type kinetics. Modified polarization curves of the VWT covered electrode show an enhanced anodic reaction and an almost unaltered cathodic reaction. The NH3 dependency is dominated by the VWT coverage and it turns out that the catalytic properties of the VWT thick film are responsible for the electrode potential shift. PMID:23575035

Schönauer-Kamin, Daniela; Fleischer, Maximilian; Moos, Ralf

2013-01-01

439

Half-Cell Potential Analysis of an Ammonia Sensor with the Electrochemical Cell Au | YSZ | Au, V2O5-WO3-TiO2  

PubMed Central

Half-cell potentials of the electrochemical cell Au, VWT | YSZ | Au are analyzed in dependence on oxygen and ammonia concentration at 550 °C. One of the gold electrodes is covered with a porous SCR catalyst, vanadia-tungstenia-titania (VWT). The cell is utilized as a potentiometric ammonia gas sensor and provides a semi-logarithmic characteristic curve with a high NH3 sensitivity and selectivity. The analyses of the Au | YSZ and Au, VWT | YSZ half-cells are conducted to describe the non-equilibrium behavior of the sensor device in light of mixed potential theory. Both electrode potentials provide a dependency on the NH3 concentration, whereby VWT, Au | YSZ shows a stronger effect which increases with increasing VWT coverage. The potential shifts in the anodic direction confirm the formation of mixed potentials at both electrodes resulting from electrochemical reactions of O2 and NH3 at the three-phase boundary. Polarization curves indicate Butler-Volmer-type kinetics. Modified polarization curves of the VWT covered electrode show an enhanced anodic reaction and an almost unaltered cathodic reaction. The NH3 dependency is dominated by the VWT coverage and it turns out that the catalytic properties of the VWT thick film are responsible for the electrode potential shift. PMID:23575035

Schönauer-Kamin, Daniela; Fleischer, Maximilian; Moos, Ralf

2013-01-01

440

Electrochemical fabrication of capacitors  

DOEpatents

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.

Mansour, Azzam N. (Fairfax Sta., VA); Melendres, Carlos A. (Lemont, IL)

1999-01-01

441

Fabrication of silicon nanopillar arrays by cesium chloride self-assembly and wet electrochemical etching for solar cell  

NASA Astrophysics Data System (ADS)

A simple technology with cesium chloride (CsCl) self-assembly lithography and wet electrochemical etching is introduced to fabricate the wafer scale, disordered, well-aligned, and high aspect ratio silicon nanopillars. The original nano structures of CsCl islands with diameters of 500-2000 nm are formed by self-assembly and used as template of lift-off for the nanoporous gold film for wet electrochemical etching as the catalyst in etching solution of HF and H2O2. The average diameter of silicon nanopillars is determined by the CsCl nanoislands with 500-2000 nm, and the height of silicon nanopillars is mainly determined by the etching time in etching solution with 3-12 ?m. The aspect ratio can achieve to 60. The solar cells with different height nanopillars are made for the research of photovoltaic conversion efficiency (PCE). The reflectance of the nanopillars with different height is measured from the wavelength of 400 to 1000 nm and the 9 ?m height silicon nanopillars has the lowest one which is below 3%. The PCE shows the highest value of 14.19% at the condition of 3 ?m height nanopillars and 12.18% of planar one with the same fabrication process.

Liu, Jing; Zhang, Xinshuai; Dong, Gangqiang; Liao, Yuanxun; Wang, Bo; Zhang, Tianchong; Yi, Futing

2014-01-01

442

Electrochemical performance of solid oxide fuel cells having electrolytes made by suspension and solution precursor plasma spraying  

NASA Astrophysics Data System (ADS)

Yttria-stabilized zirconia (YSZ) electrolytes were deposited by suspension plasma spraying (SPS) and solution precursor plasma spraying (SPPS). The electrolytes were evaluated for permeability, microstructure, and electrochemical performance. With SPS, three different suspensions were tested to explore the influence of powder size distribution and liquid properties. Electrolytes made from suspensions of a powder with d50 = 2.6 ?m were more gas-tight than those made from suspensions of a powder with d50 = 0.6 ?m. A peak open circuit voltage of 1.00 V was measured at 750 °C with a cell with an electrolyte made from a suspension of d50 = 2.6 ?m powder. The use of a flammable suspension liquid was beneficial for improving electrolyte conductivity when using lower energy plasmas, but the choice of liquid was less important when using higher energy plasmas. With SPPS, peak electrolyte conductivities were comparable to the peak conductivities of the SPS electrolytes. However, leak rates through the SPPS electrolytes were higher than those through the electrolytes made from suspensions of d50 = 2.6 ?m powder. The electrochemical test data on SPPS electrolytes are the first reported in the literature.

Marr, M.; Kuhn, J.; Metcalfe, C.; Harris, J.; Kesler, O.

2014-01-01

443

Electrochemical behavior and biological response of Mesenchymal Stem Cells on cp-Ti after N-ions implantation  

NASA Astrophysics Data System (ADS)

Titanium and its alloys are most widely used as implant materials due to their excellent biocompatibility, mechanical properties and chemical stability. In this study Nitrogen ions of known dosage were implanted over cp-Ti by Pelletron accelerator with beam energy of 0.25 MeV.The atomic force microscopy of bare and nitrogen implanted specimens confirmed increase in surface roughness with increase in nitrogen ions concentration. X-ray diffraction patterns of ions implanted surfaces validated the formation of TiN0.3 and Ti3N2-xnitride phases. The tendency to form passive film and electrochemical behavior of these surfaces in ringer lactate (RL) solution was evaluated by Potentiodynamic polarization and electrochemical impedance spectroscopy respectively. It is proved that nitrogen ions implantation was beneficial to reduce corrosion rate and stabilizing passive film by increasing charge transfer resistance in RL. It was concluded that morphology and proliferation of Mesenchymal Stem Cells on nitrogen ions implanted surfaces strongly depends on surface roughness and nitride phases.

Rizwan, M.; Ahmad, A.; Deen, K. M.; Haider, W.

2014-11-01

444

Differential cytokine expression and regulatory cells in patients with primary and secondary Sjögren's syndrome.  

PubMed

Sjögren's syndrome (SS) is an autoimmune disease characterized by lymphocytic infiltration of the salivary and lacrimal glands. The aim of the study was to characterize and compare the presence of diverse cytokines and regulatory T and B cells in lip minor salivary gland (MSG) biopsies from patients with primary Sjögren's syndrome (pSS), secondary SS (sSS), and patients with connective tissue disease (CTD) without (w/o) SS. We included samples of MSG from 15 pSS, 24 sSS (six scleroderma, nine rheumatoid arthritis and nine lupus patients) and 15 patients with CTD w/o SS. Tissues were examined by an indirect immunoperoxidase technique (goat polyclonal anti-human IL-19, goat polyclonal anti-human IL-22 or mouse monoclonal anti-human IL-24). To determine the subpopulation of CD4(+)/IL-17A(+)-, CD4(+)/IL-4(+)-, CD4(+)/IFN-?(+)-expressing T cells, CD25(+)/Foxp3(+) Treg cells and CD20(+)/IL-10(+)-producing B cell subset, a double-staining procedure was performed. We estimated the mean percentage of positively staining cells in two fields per sample. CD4(+)/IFN-?(+), CD4(+)/IL-4(+) and IL-22(+) cell percentages were elevated in both SS varieties; however, the cells were more prevalent in pSS. Patients with pSS had a high number of CD4(+)/IL-17A(+) and IL-19(+) T cells and a lower percentage of IL-24(+) cells (P < 0.05). The Treg and IL-10-producing B cells were increased in pSS (P < 0.05). Concluding, in our patients, a pro-inflammatory and regulatory balance coexists in SS, being both responses more intense in pSS. The explanation of these differences may be related to disease activity, disease duration and treatment. PMID:25346207

Furuzawa-Carballeda, J; Sánchez-Guerrero, J; Betanzos, J L; Enriquez, A B; Avila-Casado, C; Llorente, L; Hernández-Molina, G

2014-12-01

445