Physical Sciences and Mathematics Commons^™

Martian Xenon Components In Basaltic Shergottite Meteorites, Katherine Delene Ocker Stone

Doctoral Dissertations

Analyses of Chassigny, Nakhla, and ALH84001 reveal, in addition to a Xe component from the martian atmosphere, a second component loosely attributed to the martian "interior." This appears to be a mixture of solar- and fission- (²⁴⁴Pu) derived xenon components. The proportions are consistent in each meteorite but vary from meteorite to meteorite. The working hypothesis is that this variation reflects different contributions of solar (mantle-derived) and fission (crustal-derived) xenon to each parent melt.

This study focused on mineral separates from two basaltic shergottites, Shergotty and EETA79001 Lithology-B (EETA), chosen to reflect, as far as possible, the extremes …

Polymer-Supported 14-Crown-4 And Bifunctional Resins For Selective Metal Ion Complexation: Synthesis And Characterization, Christy L. Stine

Doctoral Dissertations

Polymer-supported 14-crown-4 and bifunctional resins containing amine and phosphonate ester ligands were synthesized and characterized. Complexation studies were performed to evaluate the metal ion selectivity of the resins.

The immobilization of 14-crown-4 onto crosslinked polymer supports for the complexation of Li(l) from aqueous solutions was studied. M any methods were attempted, but etherification of the hydroxymethyl form of 14-crown-4 was found to be the most successful. The polymers examined were poly(vinylbenzyl chloride), poly(vinylbenzyl chloride)-co-acrylamide and poly(glycidyl methacrylate). The amount of Li(l) complexed by the crown ether supported polymers was affected by the polarity (i.e., hydrophilicity) of the polymer matrix. The …

Magnetic Properties Of Nanoparticle Systems Of Fe, Co, Ni, And Fept, Created By Ion Implantation, Korey Dean Sorge

Doctoral Dissertations

Magnetization measurements have been performed on nanoparticle arrays of Fe, Co, Ni, and FePt in single-crystal substrates. Materials are formed by ion implantation into a layer followed by thermal annealing to give electrically isolated but crystallographically textured arrays. Studies show competition between effective single-particle anisotropy (due to magnetocrystalline, shape, surface, and stress effects) and macroscopic anisotropy due to dipolar interactions.

Results of these measurements are compared to expectations found in the well-known Stoner-Wohlfarth model of non-interacting, uniaxial particles. While this model is extensively used in magnetic materials research, the missing effects from dipolar interactions between particles give very different results …

The Use Of Native And Modified Cyclodextrins For Method Development In Capillary Electrophoresis And Chemical Sensor Applications, Mustafa Culha

Doctoral Dissertations

The development and design of novel methods and materials for separation and sensing systems have critical importance for the analysis of complex mixtures. In these systems, molecular recognition is the key element for desired selectivity and it can only be achieved using rationally designed, chemically selective reagents. Cyclodextrins (CDs) are a group of macro-cyclic molecules that can recognize certain analytes depending on their shape and size. In this work, the primary goal was the design and development of CD-based separation and sensing systems. Native and derivatized CDs were utilized to develop methods for separation of a complex mixture containing six …

Group 4 Metallocene And Half-Sandwich Derivatives Of Spherosilicate: Preparation Fromsi8o20(Snme3)8 And Their Olefin Polymerization Activity, Suree Saengkerdsub

Doctoral Dissertations

Three metallocene and half-sandwich Group 4 complexes of cuboctameric

spherosilicate (Si8O20(TiCp2Cl)8, Si8O20(ZrCp2Cl)8, and Si8O20(TiCp*Cl2)8) were successfully prepared by the exchange reaction of Group 4 metal chlorides with the spherosilicate starting material, Si8O20(SnMe3)8. These complexes were found to be catalytically active in olefin polymerization. Their preparative reactions clearly demonstrate a synthetically useful route towards many other derivatives of spherosilicate through the Si8O20(SnMe3)8 starting material. A new synthesis of the key precursor, octa(trimethyltin) cuboctameric spherosilicate Si8O20(SnMe3)8, was developed. It was found that most of the waters of hydration of the initial hydrate ([NMe4][Si8O20] @ n H2O, = 60! 70) could be removed …

Optimal Control Problems In Pde And Ode Systems, Hem Raj Joshi

Doctoral Dissertations

This dissertation contains three separate optimal control problems involving partial differential equations (PDEs) or ordinary differential equations (ODEs). In each problem, an objective functional representing the goal of the control process is minimized. First, a system of ordinary differential equations which describe the interaction of Human Immunodeficiency Virus (HIV) and CD4+T-cells in the human immune system is studied. Two controls representing drug treatment strategies of this model are explored. Existence and uniqueness results for the optimal control pair are established. The optimality system is derived and then solved numerically using an iterative method with the Runge-Kutta fourth order scheme.

Second, …

On Reproducing Kernels And Invariant Subspaces Of The Bergman Shift, George Chailos

Doctoral Dissertations

No abstract provided.