No description available.

Thesis (M.App.Sc.) - Carleton University, 2006. / Includes bibliographical references (p. 137-146). Also available in electronic format on the Internet.

Thesis (M. Eng.)--Carleton University, 1992. / Also available in electronic format on the Internet.

Thesis (M.S. in Operations Research) Naval Postgraduate School, March 1997. / Thesis advisor, Garth V. Hobson. Includes bibliographical references (p. 59). Also available online.

Carbonyl reduction is a fundamental transformation that underpins synthetic chemistry. The re-routing of carbonyl reduction through less-conventional intermediates allows new selectivity and reactivity to be found in the resulting reaction space. We have shown for the first time that the unusual radical anions formed by electron transfer to the ester carbonyl group can be exploited in additions to alkenes. We have demonstrated that the reductive cyclisations of lactones, triggered by electron-transfer from SmI2-H2O, allow for highly decorated cyclopentane and cycloheptane ring systems to be constructed. Futhermore, the reductive cyclisations of lactones can be exploited in cyclisation cascades. The cascade sequences involve the generation and trapping of unusual radical anions formed from the ester carbonyl followed by the trapping of more conventional radical anions from the carbonyl groups of ketone intermediates.

No description available.

The stable isotope compositions (chlorine, oxygen, and hydrogen), major anion concentrations, and major/minor cation concentrations of 37 thermal (any spring water with temperature at least 6.5° C above mean ambient air temperature) and mineral springs from the Cascade volcanic arc system were measured in order to better determine chlorine sources within the Cascades hydrothermal systems, and thus place better constraints on halogen flux through the subduction zone. Typically, most subduction zone flux calculations have been limited to the study of the erupted magmas and gases from fumarole vents, yet magmatic discharge through thermal springs may be considerable, particularly those in the often ignored forearc. Additionally, 9 geochemically well characterized lavas from across the Mt. St. Helens/Mt. Adams region of the Cascade arc (Leeman et al. 2001, 2005) were analyzed for their halogen concentrations, as well as their Cl stable isotope composition. Cl concentrations in the thermal springs range from 6 to 13,850 ppm and have δ37Cl values that range from -0.1‰ to + 1.9‰ (average = +0.8 ± 0.4‰; error = ± 0.2‰), with no systematic variation along or across the arc. The slightly positive values (~0.0 to +0.9‰) may be explained by fluid-rock interaction with underlying lithologic units, such as 37Cl-enriched volcanic sequences, and/or serpentinites or oceanic crust of accreted oceanic terranes. Another process possibly contributing to these positive δ37Cl values, particularly those with δ37Cl > 1‰, is magmatic HCl fractionation during degassing generating an enriched 37Cl vapor which mixes with thermal waters. We cannot completely rule out slab-derived altered oceanic crustal chlorine that has degassed into the springs, although most slab Cl is believed to have already been devolatilized from the slab before reaching sub-arc depths corresponding to longitudes where these springs are located at the surface. Lavas from the Columbia transect across the arc exhibit highest Cl concentrations at the volcanic front compared to the forearc and backarc. Br, like Cl, exhibits highest concentrations along the volcanic front. F and I show a progressive decrease in concentration from forearc to backarc which may demonstrate the putative early surge of fluids/fluid mobile element loss early in subduction at relatively shallow depth. δ37Cl values range from -0.1 to +0.8‰ (error = ± 0.2‰) and may reflect a component of assimilation of crustal material, or is derived from an enriched mantle, although we cannot completely rule out some isotopic fractionation and/or slab-derived chlorine. / text

No description available.

, Diss--Humboldt-Universität Berlin, 2003.

Mémoire (M.P.M.O.)-- Université du Québec à Chicoutimi, 1988. / Document électronique également accessible en format PDF. CaQCU