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 …

Pattern Recognition For Electric Power System Protection, Yong Sheng

Doctoral Dissertations

The objective of this research is to demonstrate pattern recognition tools such as decision trees (DTs) and neural networks that will improve and automate the design of relay protection functions in electric power systems. Protection functions that will benefit from the research include relay algorithms for high voltage transformer protection (TP) and for high impedance fault (HIF) detection. A methodology, which uses DTs and wavelet analysis to distinguish transformer internal faults from other conditions that are easily mistaken for internal faults, has been developed. Also, a DT based solution is proposed to discriminate HIFs from normal operations that may confuse …

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 …

Modular Machine Learning Methods For Computer-Aided Diagnosis Of Breast Cancer, Mia Kathleen Markey '94

Doctoral Dissertations

The purpose of this study was to improve breast cancer diagnosis by reducing the number of benign biopsies performed. To this end, we investigated modular and ensemble systems of machine learning methods for computer-aided diagnosis (CAD) of breast cancer. A modular system partitions the input space into smaller domains, each of which is handled by a local model. An ensemble system uses multiple models for the same cases and combines the models' predictions.

Five supervised machine learning techniques (LDA, SVM, BP-ANN, CBR, CART) were trained to predict the biopsy outcome from mammographic findings (BIRADS™) and patient age based on a …

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.

Asp -Pricing: A Black -Scholes Option Pricing Formulation, Chaitanya Singh

Doctoral Dissertations

The Applications Service Provider (ASP) arrangement has engendered a revolution in the area of corporate information technology (IT) by transforming software from a packaged off-the-shelf product to an on-line virtual service.

The focus of this study is to establish a sound mathematical foundation for evaluating software rental agreements (embedding exit flexibility) by incorporating a real options framework (based upon the Black-Scholes approach) into the traditional capital budgeting technique. The static discounted cash flow or net present value analysis may not adequately serve as a ‘barometer’ of outsourcing value due to its inherent weaknesses. On the other hand, the options approach …

Fuzzy Product -Limit Estimators: Soft Computing In The Presence Of Very Small And Highly Censored Data Sets, Kian Lawrence Pokorny

Doctoral Dissertations

When very few data are available and a high proportion of the data is censored, accurate estimates of reliability are problematic. Standard statistical methods require a more complete data set, and with any fewer data, expert knowledge or heuristic methods are required. In the current research a computational system is developed that obtains a survival curve, point estimate, and confidence interval about the point estimate.

The system uses numerical methods to define fuzzy membership functions about each data point that quantify uncertainty due to censoring. The “fuzzy” data are then used to estimate a survival curve, and the mean survival …

Modeling And Experimental Verification Of Growth Of An Axisymmetric Cylindrical Rod By Three-Dimensional Laser-Induced Chemical Vapor Deposition, Qing Chen

Doctoral Dissertations

Three-dimensional laser-induced chemical vapor deposition (3D-LCVD) is a recently developed micro-manufacturing process that holds great potential for the production of complex microstructures with high aspect ratio. A laser beam is focused through a vacuum chamber window onto a movable substrate. The heat from the laser at or near the focal spot on the substrate induces the decomposition reaction of precursor gas in the chamber. As a result, solid-phase reaction products are deposited on the substrate to form the microstructure. In this dissertation, a numerical model is developed for simulating kinetically-limited growth of an axisymmetric cylindrical rod by pre-specifying the surface …