Physical Sciences and Mathematics Commons^™

Dipole-Bound Anions, Nathanael Isaac Hammer

Doctoral Dissertations

Any molecule with a dipole moment above approximately 2.5 Debye can form a stable negative ion (dipole-bound anion). These anions are best produced by “resonance” charge exchange from atoms in high Rydberg states (Rydberg electron transfer, RET). RET to form dipole-bound anions occurs over a narrow range of effective principle quantum number, n*. Dipole-bound anions for 32 molecules with dipole moments between 2.5 and 6.0 Debye have been studied. The excess electron in such an anion is very diffuse and weakly bound. Binding energies (electron affinities, EAs) are estimated from the narrow range of n* at which charge exchange occurs …

Performance Improvements Of Common Sparse Numerical Linear Algebra Computations, Piotr Rafal Luszczek

Doctoral Dissertations

Manufacturers of computer hardware are able to continuously sustain an unprecedented pace of progress in computing speed of their products, partially due to increased clock rates but also because of ever more complicated chip designs. With new processor families appearing every few years, it is increasingly harder to achieve high performance rates in sparse matrix computations. This research proposes new methods for sparse matrix factorizations and applies in an iterative code generalizations of known concepts from related disciplines. The proposed solutions and extensions are implemented in ways that tend to deliver efficiency while retaining ease of use of existing solutions. …

An Individual- Based Model For The Toxic Algae Species Pseudo-Nitzschia Multiseries, Maria Siopsis

Doctoral Dissertations

In 1987 an outbreak of a previously unobserved disease occurred in Canada and was traced back to the toxin domoic acid produced by the diatom Pseudo-nitzschia multiseries. Since then, fisheries closures due to domoic acid have occurred worldwide. Pseudo-nitzschia species produce domoic acid under nutrient stress, including low silicon or phosphorus under high nitrogen conditions. However, it is still unclear what conditions cause the dangerously high levels that have sometimes been observed. We present an individual-based algae model detailing the physiology of an algal cell with a focus on nutrient and energy flows to delineate the causes of domoic acid …

Understanding Wavelet Analysis And Filters For Engineering Applications, Chethan Bangalore Parameswariah

Doctoral Dissertations

Wavelets are signal-processing tools that have been of interest due to their characteristics and properties. Clear understanding of wavelets and their properties are a key to successful applications. Many theoretical and application-oriented papers have been written. Yet the choice of a right wavelet for a given application is an ongoing quest that has not been satisfactorily answered. This research has successfully identified certain issues, and an effort has been made to provide an understanding of wavelets by studying the wavelet filters in terms of their pole-zero and magnitude-phase characteristics. The magnitude characteristics of these filters have flat responses in both …

Study Of Energy Sampling Weights In The Dø Detector Using Multiparameter Fitting Method, Qun Yu

Doctoral Dissertations

The DØ calorimeter at Fermilab is a sampling calorimeter measuring the energy of particles produced in high energy proton-antiproton collisions. A set of accurate sampling weights is of significant importance to DØ research activity. The objective of this work was to obtain a set of optimized sampling weights for the DØ central calorimeter, the Inter-Cryostat Detector (ICD), the Central Calorimeter Massless Gap (CCMG), and the End Calorimeter Massless Gap (ECMG).

The foundation of the optimization method is that, in high energy physics, the ratio of energy E and the corresponding momentum P of a particle is approximately 1, in units …

Machine Learning Approaches For Determining Effective Seeds For K -Means Algorithm, Kaveephong Lertwachara

Doctoral Dissertations

In this study, I investigate and conduct an experiment on two-stage clustering procedures, hybrid models in simulated environments where conditions such as collinearity problems and cluster structures are controlled, and in real-life problems where conditions are not controlled. The first hybrid model (NK) is an integration between a neural network (NN) and the k-means algorithm (KM) where NN screens seeds and passes them to KM. The second hybrid (GK) uses a genetic algorithm (GA) instead of the neural network. Both NN and GA used in this study are in their simplest-possible forms.

In the simulated data sets, I investigate two …

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 …

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

Doctoral Dissertations

No abstract provided.

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, …

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 …

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 …

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 …

Diagenesis Of Upper Cambrian Mount Simon Sandstone In The Illinois Basin - Microscale Investigation Of Basinal Fluid Migration And Mass Transfer, Zhensheng Chen

Doctoral Dissertations

A series of investigations were conducted to evaluate microscale evidence for basinal fluid migration in the Illinois basin during diagenesis of the Upper Cambrian Mount Simon Sandstone. Samples were examined using transmitted light and cathodoluminescence (CL) petrography, fluid inclusion analysis, and Secondary Ion Mass Spectrometry (SIMS) analysis of ¹⁸O/¹⁶O ratios and trace element compositions. Preliminary investigation of in situ laser ablation ⁴⁰Ar-³⁹Ar age dating techniques on authigenic K-feldspar over growths was also completed.

Two major generations of quartz overgrowths are observed, on the basis of transmitted light and CL petrography and fluid inclusion studies. …

Two Body Dirac Equations And Nucleon Nucleon Scattering Phase Shift Analysis, Bin Liu

Doctoral Dissertations

In this dissertation, the nucleon-nucleon interaction is investigated by using the meson exchange model and the two body Dirac equations of constraint dynamics. This approach to the two body problem has been successfully tested for QED and QCD relativistic bound states. An important question we wish to address is whether or not this approach is also valid in the two body nucleon-nucleon scattering problem. This test involves a number of related problems.

First we must reduce our two body Dirac equations exactly to a Schr¨odinger-like equation. This can be done without making any assumptions or approximations and unlike other relativistic …

Pedogenic Relationships In A Texas Vertisol Climosequence Defined By Geochemical Mass Balance Of Whole Soil And Chemistry Of Iron-Manganese Nodules, Cynthia A. Stiles

Doctoral Dissertations

Climosequence Vertisol profiles derived from the Upper Beaumont Formation in the Gulf Coastal Prairie physiographic province of Texas were examined for geochemical trends ascribed to different precipitation regimes. Mass-balance relationships were utilized for the comparisons. Compositional differences in zirconium (Zr) content between the solum and lower sub-soil precluded it use an immobile strain (volumetric change) indicator. This difference was correlated to sand weight percent (r² = 0.65**). Titanium (Ti) content did not shift correlatively with depth, thus making Ti the preferred strain index element for mass-balance calculations. Depths at which the Zr compositions shifted were not directly related to …

Reversible Melting And Crystallization Of Short And Long Flexible Chain Molecules By Temperature-Modulated Calorimetry, Jeongihm Pak

Doctoral Dissertations

Melting and crystallization of linear, flexible molecules of different lengths was studied by temperature-modulated differential scanning calorimetry, TMDSC. Various techniques for TMDSC with single and multifrequency modulations have been analyzed to optimize the conditions for the present study. The finally chosen method involved a quasi-isothermal mode with a temperature amplitude of 0.5 K and a period of 60 s (frequency = 0.167 Hz). The interpretation of the reversible and irreversible melting was developed by comparison of a variety of different modes of analysis (sinusoidal, sawtooth, and complex sawtooth). The analyzed molecules ranged from n-paraffins, oligomeric fractions of polyethylene and poly(oxyethylene) …

An Individual-Based Approach To Population Dynamics With Applications To Sockeye Salmon And Iteroparous Organisms, Cynthia Moira Krohn

Doctoral Dissertations

Individual-based models have been used to study the population dynamics of semelparous and iteroparous organisms. The rst model, developed for sockeye salmon ( On-corhynchus nerka), was based on the physiology of the individual and incorporated into a population model via a McKendrick-von Foerster type partial di
erential equation. Cycles of population abundance historically found in the Fraser River system were recreated through model simulations. Explanations for the appearance of the cycling were investigated and tested. The results showed that density- and size-dependent mortality were not necessary for cycling to appear, however their inclusion or exclusion in combination with the type …

Time Dependent Density Functional Theory Of Dynamical Response In 3d And 4d Metals, James M. Sullivan

Doctoral Dissertations

Two different but complementary quantum mechanical many-body problems are investigated. These problems include both static and dynamic aspects of the electronelectron interaction in real materials. In Chapter One, we take up the cases of Ag and Ni with a microscopic evaluation of the dielectric function and loss function using the formalism of time dependent density functional theory and all-electron techniques. We address the striking line shapes that have been recently observed via inelastic scattering experiments. The present work reveals three relevant energy scales for excitations in the selected systems. These scales are argued to be generic to a large number …

Generalizations Of The Zero-Divisor Graph Of A Ring, Shane Patrick Redmond

Doctoral Dissertations

Let R be a commutative ring with 1, and let Z(R) denote the set of zero­divisors of R. We define an undirected graph Γ(R) with vertices Z(R)* = Z(R) - {0}, where distinct vertices x and y of R are connected if and only if xy = 0. This graph is called the zero-divisor graph of R. We extend the definition of the zero-divisor graph to a noncommutative ring in several ways. Next, given a commutative ring R and ideal Ι of R, we introduce the notion of an …

Statistical Modeling And Inference Regarding Risk In Case Control Studies, Deborah Kay Shepherd

Doctoral Dissertations

Some of the common measures of risk used m epidemiology today are the relative risk, the odds ratio, the attributable risk, and the chi-square goodness of fit test. All of these measures have their shortcomings. A new approach to measuring risk in case-control studies is to use the unitless measure of the coefficient of variation of incidence of disease over the risk categories, kˆ2, first proposed by Begg et al. (1998). Begg et al. (1998), also showed that the product of multiple risk factors may be compared to an overall measure of the square of the coefficient of variation …

Statistical Properties Of Maximum Likelihood Estimates For Accelerated Lifetime Data Under The Weibull Model, Mahmoud A. Yousef

Doctoral Dissertations

Pipe rehabilitation liners are often installed in host pipes that lie below the water table. As such, they are subjected to external hydrostatic pressure. The external pressure leads to early deformation in the liners, which could ultimately lead to its failing or buckling before its expected service lifetime is achieved. Experiments involving long term buckling behavior of liners are typically accelerated lifetime testing procedures. In an accelerated testing procedure a liner is subjected to a constant external hydrostatic pressure and observed until it fails or for a certain time, t whichever occurs first. Liners that do not fail at time …

Multi -Mission Attitude Determination System For Balloon Flight, Liping Mo

Doctoral Dissertations

MADS (Multi-mission Attitude Determination System) is a new software package used to determine the attitude of instruments on a high-altitude balloon employed for scientific experiments. There is no existing system for the automated determination of the attitude of instruments in balloon experiments, so we have developed MADS to do the data analysis for balloon experiments to find the location of astrophysical sources such as gamma-ray or x-ray sources.

The two areas that required most work were modeling star trackers and modeling the motion of the balloon. Star trackers are used on satellites, but are far too expensive and sophisticated to …

A Multigrid Method For Elliptic Grid Generation Using Compact Schemes, Balaji S. Iyangar

Doctoral Dissertations

Traditional iterative methods are stalling numerical processes, in which the error has relatively small changes from one iteration to the next. Multigrid methods overcome the limitations of iterative methods and are computationally efficient. Convergence of iterative methods for elliptic partial differential equations is extremely slow. In particular, the convergence of the non-linear elliptic Poisson grid generation equations used for elliptic grid generation is very slow. Multigrid methods are fast converging methods when applied to elliptic partial differential equations. In this dissertation, a non-linear multigrid algorithm is used to accelerate the convergence of the non-linear elliptic Poisson grid generation method. The …

Instrument Performance Enhancement And Modification Through An Extended Instrument Paradigm, Stephen L. Mahan

Doctoral Dissertations

An extended instrument paradigm is proposed, developed and shown in various applications. The CBM (Chin, Blass, Mahan) method is an extension to the linear systems model of observing systems. In the most obvious and practical application of image enhancement of an instrument characterized by a time-invariant instrumental response function, CBM can be used to enhance images or spectra through a simple convolution application of the CBM filter for a resolution improvement of as much as a factor of two. The CBM method can be used in many applications. We discuss several within this work including imaging through turbulent atmospheres, or …