Thesis (Ph. D.)--University of Wisconsin, 1967. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliography.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1967. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliography.

Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 166-175).

Thesis (Ph.D.)--University of Missouri-Columbia, 2004. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

Thesis (Ph.D.)--University of Florida, 2004. / Typescript. Title from title page of source document. Document formatted into pages; contains 94 pages. Includes Vita. Includes bibliographical references.

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2006. / Includes bibliographical references (leaves 116-133). Also available in electronic version.

Thesis (Ph. D.)--Baylor University, 2006. / Includes bibliographical references (p. 133-144).

The reductions of WO₃ with hydrogen, with CO, and with carbon, as well as the reduction of WO₃/graphite mixtures with hydrogen, were studied using thermogravimetry, evolved gas analysis, X-ray powder diffraction, and scanning electron microscopy. The intermediate phases W₂₀O₅₈, W₁₈O₄₉ and WO₂, were observed in the reductions. The final product of the reductions with hydrogen and carbon was tungsten, and we was formed in the reduction with CO. The reaction paths in the overall processes were determined. The reactant/product gas ratio had a considerable influence on which reactions took place. The morphology of the sample was characterised at different stages of the reduction. The shape of the WO₃ particles was retained during the reduction. Particle growth was observed in the reduction with hydrogen and was attributed to the formation of WO₂(OH)₂(g). The kinetics of the reductions were investigated , and the reaction mechanisms determined. The reduction of WO₃ with CO was studied from 650 to 900°C, and occurred at a phase boundary with an activation energy of 40 kJ mol⁻¹ . The reduction of WO₂, was studied under the same conditions. The reaction also occurred at a phase boundary and had an activation energy of 62 kJ mol⁻¹. The reduction of WO₃ with carbon was studied from 935 to 1100°C and took place via CO and CO₂. Two stages were observed in the reduction . The first stage, which corresponded approximately to the formation of WO₂ had an activation energy of 66 kJ mol⁻¹ and was limited by diffusion through the porous reacting particles. The second stage was first order and had an activation energy of 40 kJ mol⁻¹. The reduction of WO₃ and WO₃ graphite mixtures with hydrogen were studied from 575 to 975 °C. The reactions were controlled by mass-transfer under the conditions investigated. The addition of carbon increased the rate of the reduction process , but did not affect the phases formed in the system. CO₂ was evolved mainly at the start, and CO mainly at the end of the process.

The redox behavior of a series of organometallic complexes containing Cp'M(NO) groups (Cp' = ƞ⁵-C₅H₅(Cp) or ƞ⁵-C₅Me₅(Cp*) ; M = Mo or W) has been investigated both by cyclic voltammetry and by chemical means. The neutral 16-electron Cp'Mo(N0)X₂ compounds (X = CL, Br or I) undergo a single, essentially reversible, one-electron reduction in CH₂CL₂/O.1M [n-Bu₄N]PF₆ at relatively low potentials (<-0.1 V vs SCE). The electrochemically observed reductions can be effected on a preparative scale by employing CP₂C0 as the chemical reductant. The isolable 17-electron [Cp'Mo (NO)X₂]•⁻ radical anions are cleanly reconverted to their 16-electron neutral precursors by treatment with [Cp₂Fe]BF₄. In contrast, the Cp'W(NO)I₂ compounds undergo rapid decomposition to their [Cp'W(NO)I]₂ monohalo dimers upon electrochemical reduction. Electrophiles NE⁺ (E = O or ϱ-O₂NC₆H₄N) undergo unprecedented insertions into the Cr-C ϭ-bonds of CpCr(NO)₂R complexes (R = Me, CH₂SiMe₃ or Ph) to afford [CpCr(N0)₂{N(E)R}]⁺ cationic complexes. Present evidence is consistent with these insertions occurring via charge-controlled, intermolecular attacks by NE⁺ at the Cr-R groups in classical SE2 processes. The newly-formed N(E)R ligands function as Lewis bases through nitrogen atoms toward the formally 16-electron [CpCr(NO)₂]⁺ cations and may be displaced from the chromium's coordination sphere by the more strongly coordinating CL⁻ anion. The resulting CpCr(NO)₂CL can be reconverted to CpCr(NO)₂R. thereby completing a cycle by regenerating the initial organometallic reactant. The entire sequence of stoichiometric reactions forming the cycle thus constitutes a selective method for the formation of new carbon-nitrogen bonds, the net organic conversions mediated by the CpCr(NO)₂ group being NE⁺ + R⁻ → N(E)R. The electrophilic [Cp'M(NO)₂]⁺ cations (Cp'=Cp or Cp* ; M = Cr, Mo or W) condense with methyl propiolate and 2,3-dimethyl-2-butene to afford cationic organometallic lactone complexes. These complexes undergo facile ⍜-dealkylation to yield the neutral Cp'M(NO)₂(ƞ¹-lactone) derivatives. Furthermore, the neutral Cp'W(NO)₂(ƞ¹-lactone) compounds decompose in air to their Cp'W(O)₂(ƞ¹-lactone) dioxo products. / Science, Faculty of / Chemistry, Department of / Graduate

Excess nutrients entering aquatic systems cause negative effects downstream. Oxidation-reduction potential (Eh) is an inexpensive proxy which can be used to define the potential nutrient reducing capacity of a system, in particular denitrification. My thesis attempts to determine effects of hydrology and vegetation manipulations on Eh in an agricultural drainage ditch with weirs using continuous automated data loggers to monitor the system. Accuracy and precision of the continuous automated data loggers was confirmed through laboratory and field testing. Effects of hydrology and vegetation on Eh were quantified during testing from May-September 2012 in east-central Mississippi. Vegetation affected Eh (t=-1.75, P=0.08, df=9,754) whereas changes in hydrology also affected Eh (t=7.05, P<0.001, df=9,754). Modeling of these variables indicated the interaction of hydrology and vegetation was the most influential factor measured. Through management of hydrology and vegetation in ditches, Eh can be managed to create conditions conducive for denitrification.