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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

The relationship between microstructure and mechanical behavior in beta titanium-vanadium alloys

Paris, Henry Grady 08 1900 (has links)
No description available.
32

Processing and properties of Ti-6A1-4V hollow sphere foams from hydride powder

Hardwicke, Canan Uslu 08 1900 (has links)
No description available.
33

Synthesis and Characterization of Vanadium and Cobalt Oxynitride Surface Chemical and Electronic Structure for Electrochemical Reduction of N2 to NH3

Osonkie, Adaeze 05 1900 (has links)
Cobalt oxynitride films formed by magnetron sputter deposition of a Co target in N2 or NH3 plasma or, alternatively, by NH3 plasma nitridation of a Co film deposited on Si(100), show a divergence of properties arising from (a) N and O interactions for N and O atoms bonded to each other or through a common metal center and (b) the oxophilicity of the metal center itself. Core and valence band X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and plane wave density functional theory (DFT) calculations have been used to probe chemical and electronic interactions of nitrogen-rich cobalt oxynitride CoO1-xNx (x > 0.7) films. DFT-based calculations supervised by the Cundari group show the zinc blende (ZB) structure is found to be energetically favored over the rocksalt (RS) structure for x > ~ 0.2, with an energy minimum observed in the ZB structure for x ~ 0.8 - 0.9. There is also agreement with experiment for core level binding energies obtained for DFT calculations based on the ZB structure and this forms the basis of a predictive model for understanding how N and O interactions impact the electronic and catalytic properties of these materials. Vanadium oxynitride films were deposited in a mixture of O2/Ar/N2 environments on α-Al2O3(0001) or SiO2/Si(100) substrates to obtain films with varied N/O stoichiometries via magnetron sputter deposition using a vanadium target. Films deposited on the Al2O3(0001) substrates generally, though not always, exhibited a (111) orientation, which is consistent with a rock salt structure. The enhancement of the surface properties of vanadium oxynitride was explored to improve its catalytic properties.
34

Electrolyte and membrane studies of the novel vanadium bromide redox flow cell

Prifti, Helen, Chemical Sciences & Engineering, Faculty of Engineering, UNSW January 2008 (has links)
The novel Vanadium Bromide (V/Br) redox flow cell employs a V (III)/V (II) couple in the negative half-cell and a Br/Br2 couple in the positive half-cell, with hydrobromic acid and hydrochloric acid as the supporting electrolyte. This study evaluated the chemical and electrochemical properties of the electrolytes and assessed experimental and commercial membranes for use in the V/Br flow cell. A number of techniques were employed to characterise the composition of the V/Br flow cell electrolytes. During charge, the conductivity of the positive half-cell electrolyte increased, whilst the density and viscosity increased. The reverse was observed for the negative half-cell. The UV-visible spectra of the electrolytes showed characteristic peak wavelengths of the vanadium oxidation states and provided and insight into the halogenated species forming during the operation of the V/Br flow cell. The electrochemical properties of the electrolytes were also examined using cyclic voltammetry. NMR studies examined the relationships between the 35CI and 79Br nuclei in the presence of halide and paramagnetic vanadium ions. It was established that the SOC and performance of the V/Br flow cell can be measured by changes in slllectral chemical shifts and line widths. Small-scale cycling experiments were conducted to evaluate the performance of ion exchange membranes in the V/Br redox flow cell. Of the membranes evaluated, a number were not suitable for use due to high membrane resistances or low chemical stability. The perfluorinated Nafion?? and Gore Select?? ion exchange membranes proved to be the most chemically inert and showed low resistances. The Gore Select?? membranes did however exhibit blistering during extended cycling. The chemical stability and cycling performance of the HiporeTM microporous separator showed promise for future studies to optimise the selectivity and ion exchange capacity of the membrane. Tests of membrane ion exchange capacity, diffusivity and conductivity mirrored the properties displayed in the cell cycling experiments. Results suggested that the structural characteristics of the membrane (including functionality and crosslinking) greatly influenced membrane properties and performance. Tests of long term stability showed a negative change in membrane properties. These changes did not however reflect measured changes during cell cycling experiments.
35

Studies in vanadium chemistry /

Salam, Md. Abdus. January 1986 (has links) (PDF)
Thesis (Ph. D.)--University of Adelaide, 1986. / Includes bibliographical references (leaves 230-242).
36

Real-time terahertz imaging using a quantum cascade laser and uncooled microbolometer focal plane array

Behnken, Barry N. January 2008 (has links) (PDF)
Dissertation (Ph.D. in Physics)--Naval Postgraduate School, June 2008. / Dissertation Advisor(s): Karunasiri, Gamani. "June 2008." Description based on title screen as viewed on August 28, 2008. Includes bibliographical references (p. 75-80). Also available in print.
37

A new type of reductor and its application to the determination of iron and of vanadium

Hendel, James Monroe, January 1922 (has links)
Thesis (Ph. D.)--Columbia University, 1922. / Includes bibliographical references.
38

Contributions to the knowledge of the electrolysis of aqueous solutions of vanadium salts

Fischer, Siegfried, January 1916 (has links)
Thesis (Ph. D.)--Columbia University, 1916. / Vita.
39

A new type of reductor and its application to the determination of iron and of vanadium

Hendel, James Monroe, January 1922 (has links)
Thesis (Ph. D.)--Columbia University, 1922. / Includes bibliographical references.
40

A gravimetric method for the quantitative determination of vanadium ...

Parks, Margaret Merriman, January 1930 (has links)
Thesis (Ph. D.)--Columbia University, 1931. / Vita. Bibliography: p. 22-23.

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