Physical Sciences and Mathematics Commons^™

Passive Ranging Using A Dispersive Spectrometer And Optical Filters, Jacob A. Martin

Theses and Dissertations

Monocular passive ranging using atmospheric oxygen absorption has been demonstrated in the past using an FTS. These instruments are very sensitive to vibration making them di cult to use on an airborne platform. This work focuses on whether passive ranging can be done with instruments that are easier to deploy. Two potential instruments are tested and compared: a diffraction grating spectrometer and optical filters. A grating spectrometer was able to estimate range to within 5% for a static solid rocket motor ring at a distance of 910 m using the NIR absorption band of oxygen. Testing at shorter ranges produced …

Epr And Endor Studies Of Point Defects In Lithium Tetraborate Crystals, Douglas A. Buchanan

Theses and Dissertations

Lithium tetraborate (Li2B4O7 or LTB) is a promising material for both radiation dosimetry and neutron detection applications. LTB crystals can be grown pure or doped with different impurities including transition-metal and rare-earth ions. Research in this dissertation focuses on undoped LTB crystals and LTB crystals doped with copper and silver. Electron paramagnetic resonance (EPR) and electron-nuclear double resonance (ENDOR) are used to characterize point defects in the lithium tetraborate crystals. Thermoluminescence (TL), photoluminescence (PL), photoluminescence excitation (PLE), and optical absorption (OA) are also used. An intrinsic hole trap associated with lithium vacancies is characterized with EPR and ENDOR and its …

Parametrizing Finite Frames And Optimal Frame Completions, Miriam J. Poteet

Theses and Dissertations

Frames are used in many signal processing applications. We consider the problem of constructing every frame whose frame operator has a given spectrum and whose vectors have prescribed lengths. For a given spectrum and set of lengths, we know when such a frame exists by the Schur-Horn Theorem; it exists if and only if its spectrum majorizes its squared lengths. We provide a more constructive proof of Horn's original result. This proof is based on a new method for constructing any and all frames whose frame operator has a prescribed spectrum and whose vectors have prescribed lengths. Constructing all such …

Hybrid Solvers For The Boolean Satisfiability Problem: An Exploration, Nicole Nelson

Theses and Dissertations

The Boolean Satisfiability problem (SAT) is one of the most extensively researched NP-complete problems in Computer Science. This thesis focuses on the design of feasible solvers for this problem. A SAT problem instance is a formula in propositional logic. A SAT solver attempts to find a solution for the formula. Our research focuses on a newer solver paradigm, hybrid solvers, where two solvers are combined in order to gain the benefits from both solvers in the search for a solution. Our hybrid solver, AmbSAT, combines two well-known solvers: the systematic Davis-Putnam-Logemann-Loveland solver (DPLL) and the stochastic WalkSAT solver. AmbSAT's design …

Investigation Of Low-Stress Silicon Nitride As A Replacement Material For Beryllium X-Ray Windows, David B. Brough

Theses and Dissertations

The material properties of low stress silicon nitride make it a possible replacement material for beryllium in X-ray windows. In this study, X-ray windows made of LPCVD deposited low stress silicon nitride are fabricated and characterized. The Young's modulus of the LPCVD low stress silicon nitride are characterized and found to be 226±23 GPa. The residual stress is characterized using two different methods and is found to be 127±25 MPa and 141±0.28 MPa. Two support structure geometries for the low stress silicon nitride X-ray windows are used. X-ray windows with thicknesses of 100 nm and 200 nm are suspended on …

Impact Of Post-Synthesis Modification Of Nanoporous Organic Frameworks On Selective Carbon Dioxide Capture, Timur İslamoğlu

Theses and Dissertations

Porous organic polymers containing nitrogen-rich building units are among the most promising materials for selective CO2 capture and separation applications that impact the environment and the quality of methane and hydrogen fuels. The work described herein describes post-synthesis modification of Nanoporous Organic Frameworks (NPOFs) and its impact on gas storage and selective CO2 capture. The synthesis of NPOF-4 was accomplished via a catalysed cyclotrimerization reaction of 1,3,5,7-tetrakis(4-acetylphenyl)adamantane in Ethanol/Xylenes mixture using SiCl4 as a catalyst. NPOF-4 is microporous and has high surface area (SABET = 1249 m2 g-1). Post-synthesis modification of NPOF-4 by nitration afforded (NPOF-4-NO2) and subsequent reduction resulted …

Thin Films Of Carbon Nanotubes And Nanotube/Polymer Composites, Anthony D. Willey

Theses and Dissertations

A method is described for ultrasonically spraying thin films of carbon nanotubes that have been suspended in organic solvents. Nanotubes were sonicated in N-Methyl-2-pyrrolidone or N-Cyclohexyl-2-pyrrolidone and then sprayed onto a heated substrate using an ultrasonic spray nozzle. The solvent quickly evaporated, leaving a thin film of randomly oriented nanotubes. Film thickness was controlled by the spray time and ranged between 200-500 nm, with RMS roughness of about 40 nm. Also described is a method for creating thin (300 nm) conductive freestanding nanotube/polymer composite films by infiltrating sprayed nanotube films with polyimide.

Comparing Theory And Experiment For Analyte Transport In The First Vacuum Stage Of The Inductively Coupled Plasma Mass Spectrometer, Matthew R. Zachreson

Theses and Dissertations

The Direct Simulation Monte Carlo algorithm as coded in FENIX is used to model the transport of trace ions in the first vacuum stage of the inductively coupled plasma mass spectrometer. Haibin Ma of the Farnsworth group at Brigham Young University measured two radial trace density profiles: one 0.7 mm upstream of the sampling cone and the other 10 mm downstream. We compare simulation results from FENIX with the experimental results. We find that gas dynamic convection and diffusion are unable to account for the experimentally-measured profile changes from upstream to downstream. Including discharge quenching and ambipolar electric fields, however, …

Modeling Radial Bernstein Modes In A Finite-Length Axisymmetric Non-Neutral Plasma, Mark Andrew Hutchison

Theses and Dissertations

Axisymmetric radial Bernstein modes are known to exist in non-neutral plasmas and have been studied theoretically and computationally in 1D, but detection of these modes has still proven to be difficult due to self-shielding. To help advance the work on this front we created a 2D particle-in-cell (PIC) code that simulates a non-neutral plasma in a Malmberg-Penning trap. A detailed description of the PIC code itself has been included that highlights the benefits of using an $r^2$--$z$ grid and how it can be tested. The focus of the PIC simulation was to discover how best to drive and detect these …

Advanced Numerical Methods In General Relativistic Magnetohydrodynamics, Michael J. Besselman

Theses and Dissertations

We show our work to refine the process of evolutions in general relativistic magnetohydrodynamics. We investigate several areas in order to improve the overall accuracy of our results. We test several versions of conversion methodologies between different sets of variables. We compare both single equation and two equations solvers to do the conversion. We find no significant improvement for multiple equation conversion solvers when compared to single equation solvers. We also investigate the construction of initial data and the conversion of coordinate systems between initial data code and evolution code. In addition to the conversion work, we have improved some …

Website Adaptive Navigation Effects On User Experiences, James C. Speirs

Theses and Dissertations

The information search process within a website can often be frustrating and confusing for website visitors. Navigational structures are often complex and multitiered, hiding links with several layers of navigation that user's might be interested in. Poor navigation causes user frustration. Adaptive navigation can be used to improve the user's navigational experience by flattening the navigational structure and reducing the number of accessible links to only those that the user would be interested in. This examines the effects on a user's navigational experience, of using adaptive navigation as the main navigational structure on a website. This study measured these effects …

A Lexicographic Product Cancellation Property For Digraphs, Kendall Manion

Theses and Dissertations

There are four prominent product graphs in graph theory: Cartesian, strong, direct, and lexicographic. Of these four product graphs, the lexicographic product graph is the least studied. Lexicographic products are not commutative but still have some interesting properties. This paper begins with basic definitions of graph theory, including the definition of a graph, that are needed to understand theorems and proofs that come later. The paper then discusses the lexicographic product of digraphs, denoted $G \circ H$, for some digraphs $G$ and $H$. The paper concludes by proving a cancellation property for the lexicographic product of digraphs $G$, $H$, $A$, …

Researching Effective Methods For Teaching The Phases Of The Moon, Heather Patti Jones

Theses and Dissertations

This study investigated the effectiveness of commonly used instructional methods for teaching the phases of the Moon to fifth and sixth grade students. The instructional methods investigated were the use of diagrams, animations, and models. The effectiveness of each method was tested by measuring students' understanding of Moon phases with a pre and post-assessment after receiving instruction with a specific method or combination of methods. These methods were then evaluated for their ability to help students learn essential concepts, reinforce relevant vocabulary and discourage misconceptions. Results showed that students had better scores with less prevalence of misconception when they were …

Microfluidic Devices With Integrated Sample Preparation For Improved Analysis Of Protein Biomarkers, Pamela Nsang Nge

Theses and Dissertations

Biomarkers present a non-invasive means of detecting cancer because they can be obtained from body fluids. They can also be used for prognosis and assessing response to treatment. To limit interferences it is essential to pretreat biological samples before analysis. Sample preparation methods include extraction of analyte from an unsuitable matrix, purification, concentration or dilution and labeling. The many advantages offered by microfluidics include portability, speed, automation and integration. Because of the difficulties encountered in integrating this step in microfluidic devices most sample preparation methods are often carried out off-chip. In the fabrication of micro-total analysis systems it is important …

Surreal Numbers, Joshua Hostetler

Theses and Dissertations

The purpose of this thesis is to explore the Surreal Numbers from an elementary, con- structivist point of view, with the intention of introducing the numbers in a palatable way for a broad audience with minimal background in any specific mathematical field. Created from two recursive definitions, the Surreal Numbers form a class that contains a copy of the real numbers, transfinite ordinals, and infinitesimals, combinations of these, and in- finitely many numbers uniquely Surreal. Together with two binary operations, the surreal numbers form a field. The existence of the Surreal Numbers is proven, and the class is constructed from …

Tuning Parameter Selection In L1 Regularized Logistic Regression, Shujing Shi

Theses and Dissertations

Variable selection is an important topic in regression analysis and is intended to select the best subset of predictors. Least absolute shrinkage and selection operator (Lasso) was introduced by Tibshirani in 1996. This method can serve as a tool for variable selection because it shrinks some coefficients to exact zero by a constraint on the sum of absolute values of regression coefficients. For logistic regression, Lasso modifies the traditional parameter estimation method, maximum log likelihood, by adding the L1 norm of the parameters to the negative log likelihood function, so it turns a maximization problem into a minimization one. To …

Acid-Base Catalysis In Proton-Coupled Electron Transfer Reactions (Pcet): The Effects Of Brönsted Bases On The Oxidation Of Glutathione And Hydroquinone, Ramos Jonnathan Medina

Theses and Dissertations

This thesis presents the results and discussion of the investigation of the effects of Brönsted bases on the kinetics and thermodynamics of two proton-coupled electron transfer processes: the mediated oxidation of glutathione and the electrochemical oxidation of hydroquinone. Proton-coupled electron transfer (PCET) is the name given to reactions that involve the transfer of electron(s) accompanied by the exchange of proton(s). PCETs are found in many chemical and biological processes, some of current technological relevance such as the oxygen reduction reaction in fuel cells, which involves the transfer of four electrons and four protons (4e-, 4H+); or the splitting of water …

Necessary And Sufficient Informativity Conditions For Robust Network Reconstruction Using Dynamical Structure Functions, Vasu Nephi Chetty

Theses and Dissertations

Dynamical structure functions were developed as a partial structure representation of linear time-invariant systems to be used in the reconstruction of biological networks. Dynamical structure functions contain more information about structure than a system's transfer function, while requiring less a priori information for reconstruction than the complete computational structure associated with the state space realization. Early sufficient conditions for network reconstruction with dynamical structure functions severely restricted the possible applications of the reconstruction process to networks where each input independently controls a measured state. The first contribution of this thesis is to extend the previously established sufficient conditions to incorporate …

Freshwater Phytoplankton Populations Detected Using High Pressure Liquid Chromatography (Hplc) Of Taxon-Specific Pigments, Lauren Jeanne Simmons

Theses and Dissertations

Phytoplankton are key primary producers in aquatic ecosystems, and the principle food source for primary consumers. Individual phytoplankton species respond to different physical, chemical and biological parameters, so monitoring taxonomic composition of the phytoplankton community is a means to monitor changes in environmental conditions. Phytoplankton community changes have frequently been monitored by estimating biomass (using chlorophyll a, measured fluorometrically), and taxonomic data obtained from cell counts. While such methods are useful, they are time-consuming. I hypothesized that high pressure liquid chromatography (HPLC) methods, which have been frequently used in marine systems, would allow separation and identification of key pigments. …

Health Care Informatics Support Of A Simulated Study, Zeinab Salari Far

Theses and Dissertations

The objective of this project is to assess the value of REDCap (Harris, 2009) by conducting a simulated breast cancer clinical trial and demonstration. REDCap is a free, secure, web-based application designed to support data capture for research studies. To assess REDCap's value, we conducted a simulation of a clinical trial study designed to compare the use of two new technologies for breast cancer diagnosis and treatment with current best practice breast cancer diagnosis and treatment. We call the trial, "Real-Time Operating Room BC Diagnostic Treatment (RORBCDT)". The RORBCDT clinical trial is designed to assess the value of a new …

Part 1. Design And Synthesis Of Cysteine/Cystine Prodrugs And Bioisosteres Including Symmetrical And Unsymmetrical Disulfides Designed To Increase Cystine Levels In The Cns In Order To Drive The Cystine/Glutamate Antiporter: A Novel Treatment For Schizophrenia And Drug Addiction. Part 2. Design And Synthesis Of Subtype Selective Ester Bioisosteres Of Bzr Ligands For Gabaa/Benzodiazepine Receptors To Enhance Metabolic Stability, Edward Merle Johnson Ii

Theses and Dissertations

Part 1. Schizophrenia is a debilitating disorder that affects almost 1% of the world's population; pharmacotherapy expenditures for this disorder exceed $10 billion dollars even though existing medications exhibit a poor safety/efficacy profile. It is estimated that 75% of patients discontinue drug treatment, in part due to poor safety/efficacy. The current data set demonstrates that cysteine prodrug NAC reverse the behavioral and neurochemical effects of PCP used to model schizophrenia.

As a result cysteine prodrugs represent a highly novel approach to treating schizophrenia; indeed, these compounds may ultimately be more effective than existing medications because these drugs target the pathology …

The Class Equation Of Gl2(Fq), Lindsey Mathewson

Theses and Dissertations

In this thesis, we discuss the conjugacy classes of the general linear group of 2 x 2 matrices over a prime field. We find the number of conjugacy classes and the class equation for GL_2 (F_q) for general prime q. We then look at some applications of the class equation, which includes finding the number of orbits when GL_2 (F_q) acts on (GL_2 (F_q))^s by conjugation. Included in this thesis is the Maple Code for generating the class equation for any prime.

Interpreting The Paleoenvironmental Context Of Marine Shales Deposited During The Cambrian Radiation: Global Insights From Sedimentology, Paleoecology, And Geochemistry, Tristan Kloss

Theses and Dissertations

Many Cambrian marine shales are traditionally thought to have been deposited under dysoxic or anoxic conditions based upon interpretations of sedimentological and ichnological fabrics. Recently a number of geochemical studies have suggested the opposite, that some Cambrian marine shales were deposited under slightly oxic to well-oxygenated conditions. Despite the significant implications redox conditions have for the paleoenvironment, paleoecology, and taphonomy of Cambrian shales, rarely are these disparate sedimentological and geochemical approaches combined for direct comparisons in a singular study of Cambrian shales. A multidisciplinary approach is used here, combining sedimentological, paleoecological, and geochemical approaches, for re-interpreting the paleoenvironmental conditions of …

Mitochondrial Targeting In Photodynamic Therapy. Metabolic And Drug Structure Requirements For Specific Mitochondrial Localization. A Pilot Investigation, Melissa Rhea Pergande

Theses and Dissertations

Photodynamic therapy (PTD) has shown promise in the treatment of certain types of cancer (Davis et al. 1985, Chen 1988). One appealing strategy under consideration to selectively target tumor cells in PDT is that of mitochondrial targeting (Chen 1988, Chen 1989). The concept of mitochondrial targeting has its origin in the pioneering observation by Chen and colleagues that an enhanced mitochondrial transmembrane potential (ΔΨmito) is a prevalent tumor cell phenotype (Davis et al. 1985, Chen 1988). Because the plasma transmembrane potential is negative on the inner side of the cell, and the mitochondrial transmembrane potential is negative on the matrix …

Pricing Of American Lookback Options Using Linear Programming, Michael Alexander Wagner

Theses and Dissertations

We will introduce the American lookback option in the Black-Scholes model. Afterwards

we will examine the process it inherits and derive and formulate the linear

program needed to price it.

As an approximation, we will apply a time-discretization and a truncation of the

innite space. The requirements for a solution are weakened and the optimization

problem is reduced to base functions,being linear functions.

In the end we study the numerical results following from the above computations.

The Measure And Instruction Of Scale In Introductory Chemistry, Karrie Linn Gerlach

Theses and Dissertations

As a student, it is fundamental to comprehend how small an atom or molecule is in order to truly understand how the world works. The American Association for the Advancement of Science (AAAS) has determined that scale is a critical theme that pervades through all areas of science and is critical to a deep understanding. This project determined that students, which are more proficient with scale and moving between the macroscopic and particle worlds, were better performers in chemistry classes. Interviews were used to determine what the students understood and what common misconceptions were present. These lead to the development …

Investigation Of The Quaternary Structure Of An Abc Transporter In Living Cells Using Spectrally Resolved Resonance Energy Transfer, Deo R. Singh

Theses and Dissertations

Förster resonance energy transfer (FRET) has become an important tool to study proteins inside living cells. It has been used to explore membrane protein folding and dynamics, determine stoichiometry and geometry of protein complexes, and measure the distance between two molecules. In this dissertation, we use a method based on FRET and optical micro-spectroscopy (OptiMiS) technology, developed in our lab, to probe the structure of dynamic (as opposed to static) protein complexes in living cells. We use this method to determine the association stoichiometry and quaternary structure of an ABC transporter in living cells. Specifically, the transporter we investigate originates …

Complexity And Uncertainty In Human And Ecological Risk Assessment, Matthew Jordan Dellinger

Theses and Dissertations

Multiple interacting stressors in the environment present increasingly complex risks to human health. Too often, however, the data required for traditional risk assessment are either lacking or unavailable at the necessary spatial or temporal scale. In addition, assessment practices and management policies need to move away from single factor approaches in order to accommodate the reality of complex chemical mixtures and environmental stressors. Recent literature suggests that a paradigm shift is under way. This points to a need for the development of new techniques both for rapid data collection and flexible risk assessment strategies that can adapt to make use …

Part I. The First Enantiospecific, Stereospecific Total Synthesis Of The Indole Alkaloid Ervincidine. Part Ii. The Synthesis Of Alpha 5 Subtype Selective Ligands For Gaba(A) /Benzodiazepine Receptors, Sundari K. Rallapalli

Theses and Dissertations

Part I. The first enantiospecific, stereospecific total synthesis of ervincidine 89 has been accomplished from commercially available D-(+)-tryptophan 37 which has served both as the chiral auxiliary and the starting material. Moreover, this is the first synthesis which unequivocally sets the stereochemistry of the hydroxyl group at C-6 in sterospecific fashion, as well as the C-16 hydroxy methyl group. The stereospecific conversion of D-(+)-tryptophan 37 into the key template (−)-Na-H, Nb-benzyl tetracyclic ketone 49 via the asymmetric Pictet-Spengler reaction (600 gram scale) and Dieckmann cyclization on multi-hundred gram scale was reduced to only two reaction vessels. The optically active tetracyclic …

Rapid Knowledge Assessment (Rka): Assessing Students Content Knowledge Through Rapid, In Class Assessment Of Expertise, Erin Margaret O'Connell

Theses and Dissertations

Understanding how students go about problem solving in chemistry lends many possible advantages for interventions in teaching strategies for the college classroom. The work presented here is the development of an in-classroom, real-time, formative instrument to assess student expertise in chemistry with the purpose of developing classroom interventions. The development of appropriate interventions requires the understanding of how students go about starting to solve tasks presented to them, what their mental effort (load on working memory) is, and whether or not their performance was accurate. To measure this, the Rapid Knowledge Assessment (RKA) instrument uses clickers (handheld electronic instruments for …