Physical Sciences and Mathematics Commons^™

The Development Of A Laminated Copolyester Electric Guitar, Addison S. Karnes

Electronic Theses and Dissertations

This thesis is an investigation of the fabrication and assembly methodologies employed in the development of a proof-of-principle prototype electric guitar composed of laminated copolyester. The objective of the project was to develop the processes and procedures to create an optimized physical and visual bond between layers to minimize vibratory dissipation, thus maximizing sustain. A high speed CNC router, abrasive waterjet, laser engraver-cutter, as well as various manual fabrication and assembly methods were investigated in the construction of the guitar prototypes. The lamination processes explored include low-temperature, heat-assisted pressure bonding, solvent and chemical welding, and contact adhesives. The project concluded …

Oxidative Damage To Dna 2´-Deoxyribose By Carbonate Radicals: Reaction Mechanisms And Products, Terence J. Moore

Electronic Theses and Dissertations

The carbonate radical anion (CO₃^•-, CR) is an important reactive oxygen species produced in vivo by one-electron oxidation of CO₂ or bicarbonate, constituents of the major physiological buffer. It was demonstrated for the first time by using an HPLC-based analysis of low-molecular products of DNA damage that CRs react with DNA 2΄-deoxyribose by the hydrogen abstraction mechanism. CRs exhibit a ~ 800-fold preference for one-electron oxidation of guanine over hydrogen abstraction from DNA sugar, in sharp contrast with •OH. CRs also have, as compared to •OH, an increased preference for the H1΄ abstraction, which is the …

Mathematical Modeling For Partial Object Detection., Ahmed Reda Amin El-Barkouky

Electronic Theses and Dissertations

From a computer vision point of view, the image is a scene consisting of objects of interest and a background represented by everything else in the image. The relations and interactions among these objects are the key factors for scene understanding. In this dissertation, a mathematical model is designed for the detection of partially occluded faces captured in unconstrained real life conditions. The proposed model novelty comes from explicitly considering certain objects that are common to occlude faces and embedding them in the face model. This enables the detection of faces in difficult settings and provides more information to subsequent …

Novel Analytical Tools For Studies In Molecular Assemblies : I. Electro-Active Single-Mode Integrated Optical Waveguides ; Ii. Coupled Plasmon Waveguide Resonances., Xue Han

Electronic Theses and Dissertations

Two optical analytical tools were developed for studying molecular assemblies at solid/liquid interfaces. Electro-active single-mode integrated optical waveguide (EA-SM-IOW) technology was developed as a platform for spectroelectrochemical investigations on redox adsorbates at the sub-monolayer level. With an optimized ultra-thin indium tin oxide film combined with a single-mode integrated optical waveguide, for the first time, a more than 14,000 times higher sensitivity (compared to conventional potential-modulated transmittance) was achieved. From optical signals, this technique was able to reconstruct electrochemical information of redox adsorbates, including the formal potential and the electron transfer rate. A few major advantages were achieved with the developed …

Thermionic Emission Properties Of Novel Carbon Nanostructures., Andriy Sherehiy

Electronic Theses and Dissertations

Materials with low work function values (< 2 eV) are highly in demand for low temperature thermionic electron emission, which is a key phenomenon for waste heat recovery applications. Here we present the study of the thermionic emission of the hybrid structure phosphorus, (P) doped diamond nano crystals grown on conical carbon nanotubes (CCNTs). The CCNTs provide the conducting backbone for the P-doped diamond nanocrystals. In the first part of this thesis thermionic emission properties of conical carbon nanotubes (CCNTs) grown on platinum wires and planar graphite foils were investigated. The work function (Φ) values extracted from the thermionic emission data range from 4.1 to 4.7 eV. The range of Φ values is attributed to the morphological characteristics, such as tip radius, aspect ratio, density, and wall structure of CCNTs. The observed lower values for Φ are significantly smaller than that of multi-walled carbon nanotubes (MWNTs). The reduced Φ values are attributed to field penetration effect as a result of the local field enhancement from these structures having high aspect ratio and an excellent field enhancement factor. The high amplification of the external field at the apex of the nanostructures is capable of reducing both the barrier height and the width, in turn contributing to the improved emission current at lower temperatures. The ultraviolet photoemission spectroscopy data of CCNTs grown on Pt wires are in reasonable agreement with the thermionic emission data. In the next part of the thesis we present work function reduction of phosphorus (P) doped (i) diamond nanocrystals grown on conical carbon nanotubes (CCNTs) and (ii) diamond films grown on silicon substrates. Thermionic emission measurements from phosphorus doped diamond crystals on CCNTs resulted in work function value of 2.23 eV. The reduced work-function is interpreted as due to the presence of the surface states and midband-gap states and no evidence for negative electron affinity was seen. However, Ultraviolet photo-spectroscopy studies on phosphorus doped diamond films yielded a work function value of ~1.8 eV with a negative electron affinity (NEA) value of 1.2 eV. Detailed band diagrams are presented to support the observed values for both cases. In addition we determined the work function values of nanocrystalline P doped diamond films grown on W foil to be significantly lower, 1.0- 1.33 eV compared to the hybrid structure and polycrystalline film on Si substrates. We studied tungsten (W) nanowires as an alternative material in place of CCNT as the supporting and conducting channel for P doped diamond crystals in a new hybrid structure. We described the process of fabrication of arrays of vertical W nanowires by microwave plasma treatment and synthesis of P doped nanocrystalline diamond on top of the reduced W nanowires. Thermionic emission measurements from the alternative hybrid structure resulted in high value of the work function ~ 5.1 eV.

The Use Of Variable-Bagging And The Cross-Validation Selector In The Prediction Of Alzheimer’S Using The Adni Database., Michael Wayne Godbey

Electronic Theses and Dissertations

Dimensionality plays a huge part in the modeling process. If there are more elements in a data set than variables in each element then there are very few restrictions in selection of an algorithm. Bagging, bootstrap aggregating (Breiman, 1994), may also be used to improve a model’s prediction capability. On the other hand, if there more variables in each observation than the number of observations in the dataset, the number of usable algorithms is greatly reduced. The recently developed algorithm, support vector machines, was designed for such situations, in comparison to algorithms such as logistic regression which have instability issues …

Aminooxy Reagents In Nanomedicine And Bioanalysis., Stephanie Mattingly

Electronic Theses and Dissertations

The development of nanomaterials as medical diagnostic and therapeutic agents is a rapidly expanding field. A brief search of the literature revealed that roughly half of all articles related to nanoparticle-based drug delivery were published after the onset of this thesis research, over the past 4 years. A few nano-based formulations have entered into clinical use, including liposomal drug formulations, protein-linked drugs, and nanoparticle-based MRI contrast agents. The chemistry that enables conjugation of a functional cargo, whether a drug, a targeting element, or a radionucleotide, to a nanocarrier is thus a critical component for development. Oximation is one of the …

Triggered Release Of Small Molecules From Solid Supports Using Heat Or An Applied Magnetic Field., Ralph Jacob Knipp

Electronic Theses and Dissertations

The reaction of an aminooxy moiety (RONH2) with an aldehyde or ketone carbonyl, an oximation reaction, results in the formation of robust oxime ether linkages. Oximation is a form of click chemistry and is chemoselective, occurs in a variety of solvents including water, and produces high yields with little to no purification. We were inspired to exploit the advantages of oximation reactions by attaching aminooxy-functionalized molecules to solid supports, thus allowing us to employ aminooxy chemistry in ways that cannot be achieved using solution phase. Chapter 1 provides a review of aminooxy chemistry, its advantages over similar reactions and its …

Using Migration Monitoring Data To Assess Bird Population Status And Behavior In A Changing Environment, Evan M. Adams

Electronic Theses and Dissertations

Across the world, researchers use migration banding stations to document bird migration and study the phenomenon. In this dissertation, I focus on ways of analyzing bird migration banding data and the utility migrating birds as indicators of ecosystem health that make these monitoring efforts more useful to answering ecological questions and managing migratory species. In Chapter 1, we provide background on hierarchical modeling and an overview of our findings. In Chapter 2, we developed and validated new methods to estimate daily changes in migratory population size while controlling for changes in detectability due to environmental conditions. In Chapter 3, this …

Phenology And Effects Of Dams On The Success Of Atlantic Salmon Smolt Migrations In The Penobscot River, Maine, Daniel S. Stich

Electronic Theses and Dissertations

Atlantic salmon Salmo salar populations are diminished throughout their range and high marine mortality is among the drivers of the failure of many stocks to recover. A goal of salmon recovery is to maximize the number of juvenile ‘smolts’ entering the ocean to offset loss therein. Dam removals and changes to hydropower allocation in Maine’s largest river, the Penobscot River, have occurred as part of the Penobscot River Restoration Project (PRRP). These activities, in addition to stocking have the potential to influence the number of smolts reaching the ocean. Telemetry was used to investigate factors influencing initiation of migratory behavior, …

Biomarker Discovery Of Liver Diseases Using Mass Spectrometry-Based Metabolomics., Xue Shi

Electronic Theses and Dissertations

Metabolomics has emerged as one of the latest of the "-omics" disciplines that can detect metabolite biomarkers in biological samples. The diverse characteristics of metabolites make the analytical platform challenging in metabolomics. Two bioanalytical platforms were developed in this study to investigate metabolite abundance changes under different biological conditions. We first developed a bioanalytical platform that coupled linear trap quadruple - Fourier transform ion cyclotron mass spectrometer (LTQ-FTICR MS) with direct infusion chip-based nano-electrospray ionization (DI-nESI) and applied it to study polychlorinated biphenyls (PCB) effects on non-alcoholic fatty liver disease (NAFLD). We also employed this platform in conjunction with in …

Assessing The Social And Ecological Factors That Influence Childhood Overweight And Obesity, Katie Callahan

Electronic Theses and Dissertations

The prevalence of childhood overweight and obesity is increasing at an alarming rate in the United States. Currently more than 1 in 3 children aged 2-19 are overweight or obese. This is of major concern because childhood overweight and obesity leads to chronic conditions such as type II diabetes and tracks into adulthood, where more severe adverse health outcomes arise. In this study I used the premise of the social ecological model (SEM) to analyze the common levels that a child is exposed to daily; the intrapersonal level, the interpersonal level, the school level, and the community level to better …

Ranking Methods For Global Optimization Of Molecular Structures, John Norman Mcmeen Jr

Electronic Theses and Dissertations

This work presents heuristics for searching large sets of molecular structures for low-energy, stable systems. The goal is to find the globally optimal structures in less time or by consuming less computational resources. The strategies intermittently evaluate and rank structures during molecular dynamics optimizations, culling possible weaker solutions from evaluations earlier, leaving better solutions to receive more simulation time. Although some imprecision was introduced from not allowing all structures to fully optimize before ranking, the strategies identify metrics that can be used to make these searches more efficient when computational resources are limited.

Mathematical Modeling Of Immune Responses To Hepatitis C Virus Infection, Ivan Ramirez

Electronic Theses and Dissertations

An existing mathematical model of ordinary differential equations was studied to better understand the interactions between hepatitis C virus (HCV) and the immune system cells in the human body. Three possible qualitative scenarios were explored: dominant CTL response, dominant antibody response, and coexistence. Additionally, a sensitivity analysis was carried out to rank model parameters for each of these scenarios. Therapy was addressed as an optimal control problem. Numerical solutions of optimal controls were computed using a forward-backward sweep scheme for each scenario. Model parameters were estimated using ordinary least squares fitting from longitudinal data (serum HCV RNA measurements) given in …

Fail-Safe Testing Of Safety-Critical Systems, Ahmed Gario

Electronic Theses and Dissertations

This dissertation proposes an approach for testing of safety-critical systems. It is based on a behavioral and a fault model. The two models are analyzed for compatibility and necessary changes are identified to make them compatible. Then transformation rules are used to transform the fault model into the same model type as the behavioral model. Integration rules define how to combine them. This approach results in an integrated model which then can be used to generate tests using a variety of testing criteria. The dissertation illustrates this general framework using a CEFSM for the behavioral model and a Fault Tree …

Late Cenozoic Evolution Of Sedimentation And Slope Stability Along The U.S. Atlantic Margin, Bradley Kevin Craig

Electronic Theses and Dissertations

The U.S. Mid-Atlantic margin,from the Norfolk Canyon south to Cape Hatteras, exhibits three major seafloor morphologies: elongated shelf-edge blowouts, the Currituck submarine landslide, and a large slope-sourced canyon failure. The late Cenozoic evolution of slope stability on the Middle Atlantic margin can be linked to the framework geology as well as spatial and temporal variations in sedimentation patterns across the margin. The framework geology impacts sediment pathways, while the shape of the margin influences the position of sediment depocenters across the margin. Changes in sedimentation rates and sediment source dictate the amount of sediment being delivered to each region and …

Constructing Water Budgets For A Coastal Stormwater Catchment To Examine Temporal Dynamics Between Urban Groundwater And Surface Runoff, Leigha E. Peterson

Electronic Theses and Dissertations

It is well understood that urbanization results in changes to the hydrologic cycle, namely increasing surface runoff production rates. Precipitation falling on impervious areas is typically directed via a network of drainage pipes to detention reservoirs, a process shown to negatively impact aquifer recharge rates. Historically, urban hydrologists have focused primarily on surface processes with little consideration to subsurface implications of the urban water cycle. Here, we present an approach to construct long-term, high-resolution water budgets for a coastal stormwater catchment resolving surface runoff and groundwater fractions within the water body and associated source-specific fluid exports to the coastal ocean. …

Analyses Of 2002-2013 China’S Stock Market Using The Shared Frailty Model, Chao Tang

Electronic Theses and Dissertations

This thesis adopts a survival model to analyze China’s stock market. The data used are the capitalization-weighted stock market index (CSI 300) and the 300 stocks for creating the index. We define the recurrent events using the daily return of the selected stocks and the index. A shared frailty model which incorporates the random effects is then used for analyses since the survival times of individual stocks are correlated. Maximization of penalized likelihood is presented to estimate the parameters in the model. The covariates are selected using the Akaike information criterion (AIC) and the variance inflation factor (VIF) to avoid …

Properties Of Small Ordered Graphs Whose Vertices Are Weighted By Their Degree, Constance M. Blalock

Electronic Theses and Dissertations

Graphs can effectively model biomolecules, computer systems, and other applications. A weighted graph is a graph in which values or labels are assigned to the edges of the graph. However, in this thesis, we assign values to the vertices of the graph rather than the edges and we modify several standard graphical measures to incorporate these vertex weights. In particular, we designate the degree of each vertex as its weight. Previous research has not investigated weighting vertices by degree. We find the vertex weighted domination number in connected graphs, beginning with trees, and we define how weighted vertices can affect …

Synthesis And Characterization Of [Vo(O2)H2edta] And Investigation Of The Reaction Between [Vohedta]-1 And Hydrogen Peroxide As A Model Catalyst For Haloperoxidases, Tinga C. O. Fon Mr.

Electronic Theses and Dissertations

Vanadium haloperoxidases (VHPOs) are enzymes that catalyse the oxidation of halide ions to hypohalous acids by hydrogen peroxide. There are many unanswered questions on the mechanism by which the oxidation reaction occurs. In this work, is reported the synthesis of [VO(O₂)H₂EDTA], studies of the effect of acid concentration on the decomposition of [VO(O₂)HEDTA]^-2, and mechanistic studies of the rate law. The decomposition reaction was found to be first order with respect to acid concentration and also [VO(O₂)HEDTA]^-2 concentration. The reaction of [VOHEDTA]^-1 and hydrogen peroxide progressed via a …

Electron Paramagnetic Resonance Imaging And Probes, Hanan B. Elajaili

Electronic Theses and Dissertations

EPR imaging at low frequency is an important method to measure in vivo physiology. Because native paramagnetic species exist at low concentrations in living systems, exogenous paramagnetic species are needed for in vivo EPR. Selection of the appropriate EPR probe allows the experimenter to obtain information about the environment of the imaged probe and its spatial distribution. Relaxation times for several nitroxide radicals were studied with the aim of understanding the relaxation mechanisms, which provides criteria for design of suitable in vivo imaging probes.

Amino-substituted trityl radicals have the potential to monitor pH in vivo, and the suitability for this …

Functional Equations With Involution Related To Sine And Cosine Functions., Allison Perkins

Electronic Theses and Dissertations

Let G be an abelian group, C be the _eld of complex numbers, _ 2 G be any _xed, nonzero element and _ : G ! G be an involution. In Chapter 2, we determine the general solution f; g : G ! C of the functional equation f(x + _y + _) + g(x + y + _) = 2f(x)f(y) for all x; y 2 G. Let G be an arbitrary group, z0 be any _xed, nonzero element in the center Z(G) of the group G, and _ : G ! G be an involution. The main goals of …

Penalized Regressions For Variable Selection Model, Single Index Model And An Analysis Of Mass Spectrometry Data., Yubing Wan

Electronic Theses and Dissertations

The focus of this dissertation is to develop statistical methods, under the framework of penalized regressions, to handle three different problems. The first research topic is to address missing data problem for variable selection models including elastic net (ENet) method and sparse partial least squares (SPLS). I proposed a multiple imputation (MI) based weighted ENet (MI-WENet) method based on the stacked MI data and a weighting scheme for each observation. Numerical simulations were implemented to examine the performance of the MIWENet method, and compare it with competing alternatives. I then applied the MI-WENet method to examine the predictors for the …

Mechanistic Insights And Functionalization Of Alkynes In Homogeneous Gold Catalysis., Manish Kumar

Electronic Theses and Dissertations

The focus of my dissertation work was to study the basic mechanistic insights of gold-catalyzed reactions. Although the various mechanistic pathways of gold catalysis are better understood nowadays, numerous questions still remain unanswered concerning the nature of deactivation of the catalyst's active species, high resistance towards protodeauration, and how we can solve these problems to improve the efficiency of gold catalysis. To address these challenges in gold catalysis we conducted first a detailed experimental study to understand the mechanism of deactivation of gold active species. Based on the combination of experimental data, we proposed that gold disproportionation is preferred as …

Electrochemical And Microfabrication Strategies For Remotely Operated Heavy Metal Sensor Networks For Water Analysis : The Dual Challenges Of Calibration-Less Measurement And Sample Pretreatment., Mohamed M. Marei

Electronic Theses and Dissertations

Current heavy metal monitoring in water utilizes sophisticated instrumental methods at centralized laboratories. For many applications, a preferable approach is the deployment of remote sensor networks. To this end, electrochemical methods in conjunction with microfabricated sensors potentially offer the required sensitivity and practical advantages including inexpensive sensors, reduced need for manual operation, reduced energy requirements, and also takes advantage of existing technologies such as communications networks for real-time data acquisition. The remote sensor platform developed herein consists of a photo-lithographically patterned gold electrode on SiO2 substrate within a custom stopped-flow thin-layer cell (TLC). Metal concentrations were evaluated by anodic stripping …

Several Functional Equations Defined On Groups Arising From Stochastic Distance Measures., Heather B. Hunt

Electronic Theses and Dissertations

Several functional equations related to stochastic distance measures have been widely studied when defined on the real line. This dissertation generalizes several of those results to functions defined on groups and fields. Specifically, we consider when the domain is an arbitrary group, G, and the range is the field of complex numbers, C. We begin by looking at the linear functional equation f(pr, qs)+f(ps, qr) = 2f(p, q)+2f(r, s) for all p, q, r, s, € G. The general solution f : G x G → C is given along with a few specific examples. Several generalizations of this equation …

Survey Of Graph Embeddings Into Compact Surfaces, Sophia N. Potoczak

Electronic Theses and Dissertations

A prominent question of topological graph theory is "what type of surface can a nonplanar graph be embedded into?" This thesis has two main goals. First to provide a necessary background in topology and graph theory to understand the development of an embedding algorithm. The main purpose is developing and proving a direct constructive embedding algorithm that takes as input the graph with a particular order of edges about each vertex. The embedding algorithm will not only determine which compact surface the graph can be embedded into, but also determines the particular embedding of the graph on the surface. The …

Student Application Of The Fundamental Theorem Of Calculus With Graphical Representations In Mathematics And Physics, Rabindra R. Bajracharya

Electronic Theses and Dissertations

One mathematical concept frequently applied in physics is the Fundamental Theorem of Calculus (FTC). Mathematics education research on student understanding of the FTC indicates student difficulties with the FTC. Similarly, a few studies in physics education have implicitly indicated student difficulties with various facets of the FTC, such as with the definite integral and the area under the curve representation, in physics contexts. There has been no research on how students apply the FTC in graphically-based physics questions.

This study investigated student understanding of the FTC and its application to graphically-based problems. Our interest spans several aspects of the FTC: …

An Inventory Of Student Recollections Of Their Past Misconceptions As A Tool For Improved Classroom Astronomy Instruction, Andrej Favia

Electronic Theses and Dissertations

My Ph.D. research is about examining the persistence of 215 common misconceptions in astronomy. Each misconception is based on an often commonlyheld incorrect belief by college students taking introductory astronomy. At the University of Maine, the course is taught in alternating semesters by Prof. Neil F. Comins and Prof. David J. Batuski.

In this dissertation, I examine the persistence of common astronomy misconceptions by the administration of a retrospective survey. The survey is a new instrument in that it permits the student to indicate either endorsement or rejection of each misconception at various stages in the student’s life. I analyze …

Dynamics Of Polyelectrolyte Adsorption On Surfaces: Applications In The Detection Of Iron In Water, Madhira N. Gammana

Electronic Theses and Dissertations

Layer by layer (LbL) self assembly is a simple multilayer thin (nanometer scale) film fabricating technique. The mechanism of film growth remains a topic of much controversy. For example, several models have been proposed to explain the origin of linear and exponential film growth that are attributed to differences in the dynamic processes that occur at the molecular level during film formation. The problem is that there are no methods that directly measure the dynamics of polymer formation during LbL film formation. In this thesis, I describe the essential elements of an ATR-IR spectroscopic method that was developed to enable …