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Electrochemical cell for in-situ x-ray characterization

Description: An electrochemical cell suitable for in-situ XRD analysis is presented. Qualitative information such as phase formation and phase stability can be easily monitored using the in-situ cell design. Quantitative information such as lattice parameters and kinetic behavior is also straightforward. Analysis of the LiMn&sub2;O&sub4; spinel using this cell design shows that the lattice undergoes two major structural shrinkages at approx. 4.0 V and approx. 4.07 V during charging. These shrinkages correlate well with the two electrochemical waves observed and indicate the likelihood of two separate redox processes which charging and discharging.
Date: August 4, 1998
Creator: Doughty, Daniel H.; Ingersoll, David & Rodriguez, Mark A.
Partner: UNT Libraries Government Documents Department
open access

Inert anodes and advanced smelting of aluminum

Description: This report provides a broad assessment of open literature and patents that exist in the area of inert anodes and their related cathode systems and cell designs, technologies that are relevant for the advanced smelting of aluminum. The report also discusses the opportunities, barriers, and issued associated with these technologies from a technical, environmental, and economic viewpoint. It discusses the outlook for the direct retrofit of advanced reduction technologies to existing aluminum smelters, and compares retrofits to ''brown field'' usage and ''green field'' adoption of the technologies. A number of observations and recommendations are offered for consideration concerning further research and development efforts that may be directed toward these advanced technologies. The opportunities are discussed in the context of incremental progress that is being made in conventional Hall-Heroult cell systems.
Date: July 1, 1999
Creator: Technologies, ASME Technical Working Group on Inert Anode
Partner: UNT Libraries Government Documents Department

Effect of Sulfur and Hydrocarbon Fuels on Titanate/Ceria SOFC Anodes

Description: The purpose of the project is to develop low-cost, high-performance anodes that offer low polarization resistance as well as improved tolerance for nonidealities in anode environment such as redox cycles, sulfur and other poisons, and hydrocarbons.
Date: January 27, 2005
Creator: Marina, O.A.; Pedersen, L.R. & Stevenson, J.W.
Partner: UNT Libraries Government Documents Department
open access

USE OF COUPLED MULTI-ELECTRODE ARRAYS TO ADVANCE THE UNDERSTANDING OF SELECTED CORROSION PHENOMENA

Description: The use of multi-coupled electrode arrays in various corrosion applications is discussed with the main goal of advancing the understanding of various corrosion phenomena. Both close packed and far spaced electrode configurations are discussed. Far spaced electrode arrays are optimized for high throughput experiments capable of elucidating the effects of various variables on corrosion properties. For instance the effects of a statistical distribution of flaws on corrosion properties can be examined. Close packed arrays enable unprecedented spatial and temporal information on the behavior of local anodes and cathodes. Interactions between corrosion sites can trigger or inhibit corrosion phenomena and affect corrosion damage evolution.
Date: February 23, 2006
Creator: Budiansky, N.D.; Bocher, F.; Cong, H.; Hurley, M.F. & Scully, J.R.
Partner: UNT Libraries Government Documents Department
open access

Flash X-Ray Injector Study

Description: The study described in this report1 models the FXR injector from the cathode to the exit of the injector. The calculations are compared to actual experimental measurements, table 1. In these measurements the anode voltage was varied by changing the Marks-Bank charging voltage. The anode-cathode spacing was varied by adjusting the location of the cathode in hopes of finding an island of minimum emittance (none found). The bucking coil current was set for zero field on the cathode. In these measurements, a pepper-pot mask was inserted into FXR at beam bug 135 and viewed downstream via a wiggle probe diagnostic at cell gap J21, figure 1. The observed expansion of the beamlets passing through the mask of known geometric layout and hole size allow a calculation of the phase space beam properties.
Date: March 26, 2004
Creator: Paul, A C
Partner: UNT Libraries Government Documents Department
open access

Edge reclamation in position-sensitive photomultiplier tubes

Description: We have investigated the performance of a position-sensitive, gamma-ray detector based on a CsI(Na) scintillator coupled to a Hamamatsu R3292 Position-Sensitive Photomultiplier Tube (PSPMT). The R3292 has an active area 10.0 cm in diameter (quoted). Utilization of the full active area of the photocathode is a goal that has been previously unrealized due to edge effects. Initial measurements with a 0.75 cm thick CsI(Na) crystal indicate that the performance (position resolution linearity) starts to degrade as one reaches a radius of only 3.5 cm, reducing the active area by 60%. Measuring the anode wires we have found that this fall off is not solely due to crystal edge effects, but rather is inherent to the tube crystal system. In this paper we describe the results of our measurements and how good performance can be maintained across a full 10cm of the tube face through the use of a few additional electronics channels.
Date: June 16, 1999
Creator: Nakae, L & Ziock, K
Partner: UNT Libraries Government Documents Department
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Corrosion prevention of Oregon's reinforced coastal bridges

Description: The Oregon Department of Transportation (Oregon DOT) maintains more than 120 coastal bridges; many are reinforced concrete structures over 15 m (50 ft) in length. Twelve of these bridges are historic structures. Oregon DOT is concerned about the ongoing deterioration of these bridges, rising maintenance and repair costs, and the need to protect Oregon’s large investment in coastal bridges. Over 80,000 m2 (850,000 ft2) of coastal bridge surface have been repaired and protected from further chloride-induced corrosion damage by using conductive coating anodes. Most of the anode area is thermal-sprayed (TS) Zn. Other anode materials include TS Ti, Zn-hydrogel, and conductive carbon paint. TS Zn anodes are estimated to have a service life exceeding 25 years but exhibit increasing anode polarization with age. Catalyzed TS Ti anodes develop no significant anode polarization and have exhibited stable long-term performance over 8 years of service. Galvanic Zn-hydrogel anodes produce a stable protection current with no evidence of aging effects over 6 years of service. The conductive carbon paint anode operates at a low anode current density and consumption rate with a low rate of acidification at the anode-concrete interface, which has contributed to a stable protection current over 17 years of service.
Date: June 1, 2004
Creator: Bullard, Sophie J.; Cramer, Stephen D.; Covino, Bernard S., Jr.; Holcomb, Gordon R.; Ziomek-Moroz, Margaret; Cryer. C.B (Oregon Dept. of Transportation, Salem, OR) et al.
Partner: UNT Libraries Government Documents Department
open access

Low cost MCFC anodes

Description: This paper outlines a project, funded under a DOE SBIR grant, which tested a potentially lower cost method of manufacturing MCFC stack anodes and evaluated the feasibility of using the technology in the existing M-C Power Corp. manufacturing facility. The procedure involves adding activator salts to the anode tape casting slurry with the Ni and Cr or Al powders. Two different processes occur during heat treatment in a reducing environment: sintering of the base Ni structure, and alloying or cementation of the Cr or Al powders. To determine whether it was cost-effective to implement the cementation alloying manufacturing process, the M-C Power manufacturing cost model was used to determine the impact of different material costs and processing parameters on total anode cost. Cost analysis included equipment expenditures and facility modifications required by the cementation alloying process.
Date: December 31, 1996
Creator: Erickson, D.S.
Partner: UNT Libraries Government Documents Department
open access

Effect on Performance of Composition of Li-Ion Carbon Anodes Derived from PMAN/DVB Copolymers

Description: The effects on electrochemical performance of the nitrogen content of disordered carbons derived from polymethacryonitrile (PMAN)-divinylbenzene (DVB) copolymers were examined in galvanostatic cycling tests between 2 V and 0.01 V vs. Li/Li+ in lM LiPF<sub>6</sub>/ethylene carbonate (EC)-dimethyl carbonate (DMC). The first-cycle reversible capacities and coulombic efficiencies increased with increase in the level of nitrogen for samples prepared at 700&deg;C. However, the degree of fade also increased. Similar tests were performed on materials that were additionally heated at 1,000&deg; and 1,300&deg;C for five hours. Loss of nitrogen, oxygen, and hydrogen occurred under these conditions, with none remaining at the highest temperature in all cases but one. The pyrolysis temperature dominated the electrochemical performance for these samples, with lower reversible and irreversible capacities for the first intercalation cycle as the pyrolysis temperature was increased. Fade was reduced and coulombic efficiencies also improved with increase in temperate. The large irreversible capacities and high fade of these materials makes them unsuitable for use in Li-ion cells.
Date: May 14, 1999
Creator: Even, William R. & Guidotti, Ronald A.
Partner: UNT Libraries Government Documents Department
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IGT Stack No. 6 (SDG{ampersand}E-1) Test Plan and Component Specification Document: Topical report, March 1996

Description: The purpose of Stack-6 (SDG{ampersand}E-1) is to scale up and demonstrate the long term performance and endurance characteristics of the IMHEX stack design and the Generation No. 2 cell components (improved pore matching electrodes) in a 20 cell subscale stack test.
Date: December 31, 1997
Partner: UNT Libraries Government Documents Department

Nanostructured Metal Oxide Anodes

Description: This summarizes NREL's FY09 battery materials research activity in developing metal oxide nanostructured anodes to enable high-energy, durable and affordable li-ion batteries for HEVs and PHEVs.
Date: May 1, 2009
Creator: Dillon, A. C.; Riley, L. A.; Lee, S. H.; Kim, Y. H.; Ban, C.; Gillaspie, D. T. et al.
Partner: UNT Libraries Government Documents Department
open access

Gas Discharge Switch Evaluation for Rhic Beam Abort Kicker Application.

Description: A gas discharge switch EEV HX3002 is being evaluated at Brookhaven National Laboratory as a possible candidate of RHIC Beam Abort Kicker modulator main switch. At higher beam energy and higher beam intensity, the switch stability becomes very crucial. The hollow anode thyratron used in the existing system is not rated for long reverse current conduction. The reverse voltage arcing caused thyratron hold-off voltage de-rating has been the main limitation of the system operation. To improve the system reliability, a new type of gas discharge switch has been suggested by Marconi Applied Technology for its reverse conducting capability.
Date: June 30, 2002
Creator: Zhang, W.; Sandberg, J.; Sheldrake, R. & Pirrie, C.
Partner: UNT Libraries Government Documents Department
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Pulsed X-ray Characterization of Stripline Micro-Channel Plate Gated Imager

Description: We report on characterization of x-ray imaging arrays developed by National Security Technologies, LLC. These devices are based on a microchannel plate (MCP) with a conventional glass microchannel structure, but the top and bottom conductive coatings, rather than covering the entire area, are configured into several (4 to 8) parallel strips. Since the bias voltage is a pulse launched from one end, these operate as striplines; relative delays between these pulses give different active exposure times. Unlike the case of a static bias voltage, non-uniformities in impedance along a stripline will produce spatial fluctuations in the bias voltage. These are expected to be slight, but the very sensitive dependence of gain on voltage - approximately like Vl/4d, where l and d are the length and diameter of the channel - means there may be very significant spatial non-uniformities in gain. Flat-field calibrations are therefore required so that such effects can be unfolded from the raw images if quantitative data is required. Such flat-field and other characterization measurements, e.g. responsivity and linearity, have therefore been done with a flash X-ray radiographic system. The maximum endpoint energy is 500 keV. The duration is {approx}40 ns, and so is essentially flat (temporally) during the MCP stripline transit time, which is a maximum of 600 ps. Spatial variations are significant, but the data are corrected using independent flat-field measurements. A monochromator selects a particular X-ray transition line (typically K{alpha}) of the anode material, so that characterizations can be done for various well-defined input photon energies.
Date: March 30, 2011
Creator: F. J. Goldin, D. V. Morgan, K. J. Moy
Partner: UNT Libraries Government Documents Department
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Measurement and Simulation of Source-Generated Halos in the University of Maryland Electron Ring (Umer)

Description: One of the areas of fundamental beam physics that have served as the rationale for recent research on UMER is the study of the generation and evolution of beam halos. Recent experiments and simulations have identified imperfections in the source geometry, particularly in the region near the emitter edge, as a significant potential source of halo particles. The edge-generated halo particles, both in the experiments and the simulations are found to pass through the center of the beam a short distance downstream of the anode plane. Understanding the detailed evolution of these particle orbits is therefore important to designing any aperture to remove the beam halo.
Date: June 18, 2007
Creator: Haber, I.; Haber, I.; Bernal, S.; Kishek, R. A.; O'Shea, P. G.; Papadopoulos, C. et al.
Partner: UNT Libraries Government Documents Department
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Electronic Circuits Lectures

Description: The two-electrode vacuum tube, or diode, consists of an electron-emitting cathode surrounded by a positive anode (plate). A plot of plate current (i{sub b}) vs plate voltage (e{sub b}) is shown. At low anode voltages, the anode current is limited by the repelling effect that the negative electrons already in the space have on the electrons just being emitted (space-charge effect). When a full space charge is present, the plate current depends upon the plate voltage according to Childs law: i{sub b} {approx} e{sub b}{sup 3/2}. Increasing the plate voltage eventually results in an electron flow equal to total cathode emission, after which further increases in anode voltage will produce practically no additional current (voltage saturation). However, for high field stresses, additional electrons are pulled out of the cathode (field emission), increasing the current even further.
Date: December 1, 1947
Creator: Mozley, Robert
Partner: UNT Libraries Government Documents Department
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Effect of Vinylene Carbonate on Graphite Anode Cycling Efficiency

Description: Vinylene Carbonate (VC) was added to the electrolyte in graphite-lithium half-cells. We report its effect on the coulombic efficiency (as capacity shift) of graphite electrodes under various formation cycling conditions. Cyclic voltammetry on glassy carbon showed that VC passivates the electrode against electrolyte reduction. The dQ/dV plots of the first lithiation of the graphite suggest that VC alters the SEI layer, and that by varying the cell formation rate, the initial ratio of ethylene carbonate to VC in the SEI layer can be controlled. VC was found to decrease first cycle efficiency and reversible capacity (in ongoing cycling) when used to excess. However, experiments with VC additive used with various formation rates did not show any decrease in capacity shift.
Date: May 5, 2009
Creator: Ridgway, Paul; Zheng, Honghe; Liu, Gao; Song, Xiangun; Ross, Philip & Battaglia, Vincent
Partner: UNT Libraries Government Documents Department
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Composite Metal-hydrogen Electrodes for Metal-Hydrogen Batteries

Description: The purpose of this project is to develop and conduct a feasibility study of metallic thin films (multilayered and alloy composition) produced by advanced sputtering techniques for use as anodes in Ni-metal hydrogen batteries. The anodes could be incorporated in thin film solid state Ni-metal hydrogen batteries that would be deposited as distinct anode, electrolyte and cathode layers in thin film devices. The materials could also be incorporated in secondary consumer batteries (i.e. type AF(4/3 or 4/5)) which use electrodes in the form of tapes. The project was based on pioneering studies of hydrogen uptake by ultra-thin Pd-capped metal-hydrogen ratios exceeding and fast hydrogen charging and Nb films, these studies suggested that materials with those of commercially available metal hydride materials discharging kinetics could be produced. The project initially concentrated on gas phase and electrochemical studies of Pd-capped niobium films in laboratory-scale NiMH cells. This extended the pioneering work to the wet electrochemical environment of NiMH batteries and exploited advanced synchrotron radiation techniques not available during the earlier work to conduct in-situ studies of such materials during hydrogen charging and discharging. Although batteries with fast charging kinetics and hydrogen-metal ratios approaching unity could be fabricated, it was found that oxidation, cracking and corrosion in aqueous solutions made pure Nb films-and multiiayers poor candidates for battery application. The project emphasis shifted to alloy films based on known elemental materials used for NiMH batteries. Although commercial NiMH anode materials contain many metals, it was found that 0.24 µm thick sputtered Zr-Ni films cycled at least 50 times with charging efficiencies exceeding 95% and [H]/[M] ratios of 0.7-1.0. Multilayered or thicker Zr-Ni films could be candidates for a thin film NiMH battery that may have practical applications as an integrated power source for modern electronic devices.
Date: April 1, 1997
Creator: Ruckman, M. W.; Wiesmann, H.; Strongin, Myron; Young, Kwo & Fetcenko, M.
Partner: UNT Libraries Government Documents Department
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LOW TEMPERATURE CATHODE SUPPORTED ELECTROLYTES

Description: This report represents a summary of the work carried out on this project which started October 1999 and ended March 2003. A list of the publications resulting from the work are contained in Appendix A. The most significant achievements are: (1) Dense nanocrystalline zirconia and ceria films were obtained at temperatures &lt; 400 C. (2) Nanocrystalline films of both ceria and zirconia were characterized. (3) We showed that under anodic conditions 0.5 to 1 micron thick nanocrystalline films of Sc doped zirconia have sufficient electronic conductivity to prevent them from being useful as an electrolyte. (4) We have developed a process by which dense 0.5 to 5 micron thick dense films of either YSZ or ceria can be deposited on sintered porous substrates which serve as either the cathode or anode at temperatures as low as 400 C. (5) The program has provided the research to produce two PhD thesis for students, one is now working in the solid oxide fuel cell field. (6) The results of the research have resulted in 69 papers published, 3 papers submitted or being prepared for publication, 50 oral presentations and 3 patent disclosures.
Date: March 31, 2003
Creator: Anderson, Harlan U.; Dogan, Fatih & Petrovsky, Vladimir
Partner: UNT Libraries Government Documents Department
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Designer carbons as potential anodes for lithium secondary batteries

Description: Carbons are the material of choice for lithium secondary battery anodes. Our objective is to use designed synthesis to produce a carbon with a predictable structure. The approach is to pyrolyze aromatic hydrocarbons within a pillared clay. Results from laser desorption mass spectrometry, scanning tunneling microscopy, X-ray diffraction, and small angle neutron scattering suggest that we have prepared disordered, porous sheets of carbon, free of heteroatoms. One of the first demonstrations of template-directed carbon formation was reported by Tomita and co-workers, where polyacrylonitrile was carbonized at 700{degrees}C yielding thin films with relatively low surface areas. More recently, Schwarz has prepared composites using polyfurfuryl alcohol and pillared clays. In the study reported here, aromatic hydrocarbons and polymers which do not contain heteroatoms are being investigated. The alumina pillars in the clay should act as acid sites to promote condensation similar to the Scholl reaction. In addition, these precursors should readily undergo thermal polymerization, such as is observed in the carbonization of polycyclic aromatic hydrocarbons.
Date: July 1, 1995
Creator: Winans, R. E.; Carrado, K. A. & Thiyagarajan, P.
Partner: UNT Libraries Government Documents Department
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ELECTRON AVALANCHE MODEL OF DIELECTRIC-VACUUM SURFACE BREAKDOWN

Description: The model assumes that an 'initiating event' results in positive ions on the surface near the anode and reverses the direction of the normal component of electric field so that electrons in vacuum are attracted to the dielectric locally. A sequence of surface electron avalanches progresses in steps from the anode to the cathode. For 200 kV across 1 cm, the spacing of avalanches is predicted to be about 13 microns. The time for avalanches to step from the anode to the cathode is predicted to be about a ns.
Date: February 21, 2007
Creator: Lauer, E J
Partner: UNT Libraries Government Documents Department
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Microwave Plasma Chemical Vapor Deposition of Nano-Structured Sn/C Composite Thin-Film Anodes for Li-ion Batteries

Description: In this paper we report results of a novel synthesis method of thin-film composite Sn/C anodes for lithium batteries. Thin layers of graphitic carbon decorated with uniformly distributed Sn nanoparticles were synthesized from a solid organic precursor Sn(IV) tert-butoxide by a one step microwave plasma chemical vapor deposition (MPCVD). The thin-film Sn/C electrodes were electrochemically tested in lithium half cells and produced a reversible capacity of 440 and 297 mAhg{sup -1} at C/25 and 5C discharge rates, respectively. A long term cycling of the Sn/C nanocomposite anodes showed 40% capacity loss after 500 cycles at 1C rate.
Date: February 1, 2008
Creator: Stevenson, Cynthia; Marcinek, M.; Hardwick, L. J.; Richardson, T. J.; Song, X. & Kostecki, R.
Partner: UNT Libraries Government Documents Department
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