Physical Sciences and Mathematics Commons^™

Influence Of Mercury-Dissolved Organic Matter (Dom) Complexation On Toxicity In Natural Waters, Christina Mcnaughton

All Dissertations

Global industrialization, coupled with a large biogeochemical cycle that moves mercury through the environment, has resulted in higher mercury concentrations being detected in many environmental compartments. Although the presence of mercury in each compartment has the potential to elicit toxicity, mercury found in natural waters provides the greatest risk, due to the various reactions it can undergo, resulting in a plethora of different species.
Due to the fact that mercury contamination in aquatic systems has the potential to bioaccumulate and biomagnify up the food chain and cause toxicity, understanding the behavior of mercury in these systems is imperative in the …

Studies Of The Stability And Potential Applications Of Pyrrolidinofullerenes And Other Fullerene Derivatives, Olena Lukoyanova

All Dissertations

Over the last decade, the variety of chemically modified fullerenes and their potential applications has increased significantly. Among fullerene derivatives, pyrrolidinofullerenes are one of the most widely synthesized types since they can be easily and efficiently obtained via simple reactions from both empty and endohedral fullerenes. Although fullerenes in general and pyrrolidinofullerenes in particular have been considered for numerous applications in electronic and optoelectronic devices, photovoltaics, medicinal chemistry, etc., their potential application in the evolving field of molecular electronics has not been extensively explored. The envisioned role of the fullerenes usually involves storage or transport of electrons. Therefore, studies of …

Diversity And Abundance Of Ants At Forest Edges , Eric Paysen

All Dissertations

Fragmented habitats are a common result of human activities that involve the clearing of native vegetation for various land uses. Habitat fragmentation has two primary and inseparable components: habitat loss and insularization. Landscape-level connectivity in fragmented habitats is diminished for many species, and edge characteristics become more important as the edge-to-interior ratio increases. The study of the effects of edges on biodiversity has compelled ecologists to study them for over a century and has influenced the design and management of natural preserves. Invasion of habitats by non-native species is a phenomenon that coincides with the increased human activity typical of …

Solid Phase Crystallization Of Vanadium Dioxide Thin Films And Characterization Through Scanning Electron Microscopy, Felipe Rivera

Theses and Dissertations

Crystalline films of vanadium dioxide were obtained through thermal annealing of amorphous vanadium dioxide thin films sputtered on silicon dioxide. An annealing process was found that yielded polycrystalline vanadium dioxide thin films, semi-continuous thin films, and films of isolated single-crystal particles. Orientation Imaging Microscopy (OIM) was used to characterize and study the phase and the orientation of the vanadium dioxide crystals obtained, as well as to diferentiate them from other vanadium oxide stoichiometries that may have formed during the annealing process. There was no evidence of any other vanadium oxides present in the prepared samples. Indexing of the crystals for …

Charge Effects In Bilayer Electric Transport, Christopher Czech

All Theses

The mathematical isomorphism between the layer index in a bilayer system and the spin index in a spin-polarized system is used to draw an analogy between phenomena that occur in the two systems as a result of the electron-electron (e-e) interaction. First, the classical case of the Coulomb drag, a phenomenon resulting from momentum transfer through e-e collisions, is reviewed for both bilayer systems and spin-polarized systems. Then, the spin-backflow phenomenon, a result of the interaction-induced changes in the local quasiparticle energy that affects the charge transport in spin-polarized systems is presented. Finally, the iso-spin correlation is exploited to establish …

Distributed Web Service Coordination For Collaboration Applications And Biological Workflows, Janaka Lalith Balasooriya

Computer Science Dissertations

In this dissertation work, we have investigated the main research thrust of decentralized coordination of workflows over web services. To address distributed workflow coordination, first we have developed “Web Coordination Bonds” as a capable set of dependency modeling primitives that enable each web service to manage its own dependencies. Web bond primitives are as powerful as extended Petri nets and have sufficient modeling and expressive capabilities to model workflow dependencies. We have designed and prototyped our “Web Service Coordination Management Middleware” (WSCMM) system that enhances current web services infrastructure to accommodate web bond enabled web services. Finally, based on core …

Web Based Resource Management For Multi-Tiered Web Applications, Bryce Daniel Ott

Theses and Dissertations

The currently emerging trend of building more complex web applications to solve increasingly more involved software problems has led to the the need for a more automated and practical means for deploying resources required by these advanced web applications. As web based applications become more complex and involve more developers, greater system redundancy, and a larger number of components, traditional means of resource deployment become painfully inadequate as they fail to scale sufficiently. The purpose of this research is to provide evidence that a more sound and scalable test and deployment process can be employed and that many of the …

New Multiwavelength Variability And Optical Microvariability Investigations Of X-Ray And Radio Selected Blazars, Margaret Angela Osterman

Physics and Astronomy Dissertations

The extreme AGN known as blazars can be classified based on their spectral properties into X-ray and radio selected objects, known as XBLs and RBLs, respectively. In this work, the results of new multiwavelength campaigns are presented for two XBLs and two RBLs. Each campaign contains simultaneous observations in the radio, optical, and X-ray regimes. A campaign on a third RBL was completed using near-simultaneous archival radio, optical/IR, and gamma-ray data. The simultaneous multiwavelength behavior exhibited in each campaign was analyzed by examining the multiwavelength variability and using spectral analysis. Observations of prominent optical microvariability were quantitatively analyzed. Previously published …

Goal-Oriented Job Scheduling For Parallel Computer Systems, Sangsuree Vasupongayya

Dissertations and Theses

System administrators for parallel computers face many difficulties when managing job scheduling systems. First, current production job schedulers use many parameters, which seem flexible but it is highly challenging to configure and tune these parameters. Second, fair share is an important scheduling goal, but it is not clear what kind of fair share can be expected under current schedulers and how fair share impacts scheduling performance. Third, several job runtime prediction methods were proposed to improve inaccurate user-estimated runtimes, but these methods could under-estimate runtimes by a large amount and it is not clear whether they are practical for use …

Mathematically Modeling Pcr: An Asymptotic Approximation With Potential For Optimization, Martha J. Garlick

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

A mathematical model for PCR (Polymerase Chain Reaction) is developed using the law of mass action. Differential equations are written from the chemical equations, preserving the detail of the complementary DNA single strand being extended one bas e pair at a time. The equations for the annealing stage are solved analytically. The method of multiple scales is used to approximate solutions for the extension stage. A map is then developed from the solutions to simulate PCR. The advantage of this model is the ability to use the map to optimize the process. Our results suggest that dynamically optimizing the extension …

The Rate And Timing Of Direct Mountain Front Recharge In An Arid Environment, Silver Island Mountains, Utah, Gregory T. Carling

Theses and Dissertations

Direct mountain front recharge (MFR), water table recharge at the base of the mountain front, was evaluated on the arid (<250 mm/yr precipitation) Silver Island Mountains by comparing mountain precipitation to groundwater response. Direct MFR contributions were assessed on two catchments, one bedrock (i.e., mountain block) dominated and the other alluvial fan (i.e., mountain front) dominated. Catchment precipitation and shallow groundwater levels at each catchment outlet were measured for a 24 month period beginning October 2005. This time period captured one complete hydrologic cycle (December 2005-February 2007) for which annual and seasonal direct MFR rates were calculated. Annual direct MFR was calculated using a modified version of the water table fluctuation (WTF) method as 0.015-0.016% of precipitation on both catchments, with seasonal variations of 0% in summer up to 0.023% in winter, spring and fall. Seasonal direct MFR contributions are similar on the bedrock and the alluvial fan dominated catchments, with a notable exception during fall 2006 when direct MFR was twice as effective on the bedrock dominated system than on the alluvial fan dominated system (0.022% and 0.011% of precipitation, respectively). Darcy's law calculations show similarly low annual direct MFR contributions (0.013-0.032% of precipitation) as those calculated by the WTF method. Calculated direct MFR is 10% or less than typical calculated combined MFR (near surface recharge and deep underflow from the mountain block) for similar terrains and climates, and is only 3.5% of the combined MFR for the Silver Island Mountains as calculated by the Maxey-Eakin model. However, based on total recharge to the adjacent playa, it is apparent that the Maxey-Eakin model overestimates combined MFR, and the small calculated direct MFR is at least 50% of combined MFR. Despite some uncertainty in the numerical results, several patterns are evident in the data. The data show that direct MFR occurs in response to small rainfall events throughout much of the year, and that snowmelt is not necessary to produce direct MFR. The data also show that direct MFR responds more quickly and flushes through the system faster on the alluvial fan catchment than on the bedrock catchment.

Effects Of Water Vapor On The Kinetics Of The Methylperoxy Radical Self-Reaction And Reaction With Hydroperoxy, Alecia Mower

Theses and Dissertations

The gas phase reactions of CH3O2 + CH3O2, HO2 + HO2, and CH3O2 + HO2 in the presence of water vapor have been studied at temperatures between 263 and 303 K using laser flash photolysis coupled with UV time-resolved absorption detection at 220 nm and 260 nm. Water vapor concentration was quantified using tunable diode laser spectroscopy operating in the mid-IR. The HO2 self-reaction rate constant is significantly enhanced by water vapor, consistent with what others have reported, whereas CH3O2 self-reaction and the cross-reaction (CH3O2 + HO2) rate constants are nearly unaffected. The enhancement in the HO2 self-reaction rate coefficient …

Slowmo: A Search For Nearby Stars, Misty Adana Brown

Physics and Astronomy Theses

I report on suspected nearby stars with proper motions 1.0 arcsec > μ ≥ 0.5 arcsec/yr in the southern sky (DEC = −90° to 00°). This sample of slow-motion (SLOWMO) stars complements the work of Jao (2004), who reported on faster moving stars with μ ≥ 1.0 arcsec/yr in the entire sky for his doctoral dissertation, and the work of Finch (2007), who uncovered stars moving slower than 0.5 arcsec/yr between declinations −90° and −47°. Characterizations of SLOWMO systems include trigonometric parallaxes, optical and infrared photometry. For stars without trigonometric parallaxes, colors and apparent magnitudes are used to calculate photometric distance …

Improving Scalability And Usability Of Parallel Runtime Environments For High Availability And High Performance Systems, Thara Angskun

Doctoral Dissertations

The number of processors embedded in high performance computing platforms is growing daily to solve larger and more complex problems. Hence, parallel runtime environments have to support and adapt to the underlying platforms that require scalability and fault management in more and more dynamic environments. This dissertation aims to analyze, understand and improve the state of the art mechanisms for managing highly dynamic, large scale applications.

This dissertation demonstrates that the use of new scalable and fault-tolerant topologies, combined with rerouting techniques, builds parallel runtime environments, which are able to efficiently and reliably deliver sets of information to a large …

Total Synthesis Of An Analog Of Hydramycin And Derivatization Of Thiol-Terminated Carbohydrates And Development Of A Glycoconjugate Too Set For The Assembly And Presentation Of Carbohydrate Ligands On Surfaces, Medhanit Woldeghiorghis Bahta

Doctoral Dissertations

2-(1,2-Dihydroxy-1-(oxiran-2-yl)ethyl)-11-hydroxy-5-methyl-1Hnaphtho[ 2,3-h]chromene-4,7,12-trione (1), a pyranoanthraquinone isolated from Streptomyces violaceus P950-4, showed a potent antibacterial and cytotoxic activity. A model synthesis for analogs 2-(1,2-dihydroxy-1-(oxiran-2-yl)ethyl)-4H-chromen- 4-one (2) and2-(1-hydroxy-1-(oxiran-2-yl)ethyl)-1H-naphtho[2,3- h]chromene-4,7,12-trione (3) was developed by Dr. David White and Dr. Sarah Headrick. A new analog, 2-(1,2-dihydroxy-1-(oxiran-2-yl)ethyl)-1H-naphtho[2,3- h]chromene-4,7,12-trione (4), was designed to be structurally more similar to hydramycin with –CH2OH functionality on the pyranone ring and anthraquinone skeleton. Therefore, it is expected to have greater anticancer activity than either analogs 2 or 3. This dissertation will cover developments, challenges and solutions in …

Fabrication And Analysis Of Polymeric Nanocomposites From Cellulose Fibrils, Qingzheng Cheng

Doctoral Dissertations

A novel process using high-intensity ultrasonication (HIUS) was developed to isolate fibrils from cellulose fibers. The geometrical characteristics of the fibrils were investigated using polarized light microscopy (PLM), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Results show that small fibrils with diameter ranging from about thirty nanometers to several micrometers were peeled from the fibers. The degree of fibrillation of the fibers was significantly increased. The crystallinities or molecular structures of most of the cellulose materials were changed by HIUS treatment.

To evaluate the fibrils degradation by HIUS, a method using AFM was modified and developed to measure …

Electroanalysis Of Metals In Biological And Environmental Samples At Bismuth Electrodes, Kristie Carter Armstrong

Doctoral Dissertations

An Advanced Oxidation Process (AOP) was designed for the decomposition of organic material in blood as a pretreatment for chromium analysis. Acidified porcine blood was treated with hydrogen peroxide and UV light for 60 min. The rate of decomposition was studied using UV/Vis spectroscopy. It was found that the order of the photolytic reaction with respect to hydrogen peroxide was 0.35. The pretreated blood was subsequently analyzed for chromium content by catalytic adsorptive stripping voltammetry at a bismuth film electrode. The concentration of chromium was determined to be 6.0 " 0.3 parts per billion (ppb). A bismuth bulk electrode was …

Statistical And Machine Learning Techniques Applied To Algorithm Selection For Solving Sparse Linear Systems, Erika Fuentes

Doctoral Dissertations

There are many applications and problems in science and engineering that require large-scale numerical simulations and computations. The issue of choosing an appropriate method to solve these problems is very common, however it is not a trivial one, principally because this decision is most of the times too hard for humans to make, or certain degree of expertise and knowledge in the particular discipline, or in mathematics, are required. Thus, the development of a methodology that can facilitate or automate this process and helps to understand the problem, would be of great interest and help. The proposal is to utilize …

Parametric And Non-Parametric Regression Tree Models Of The Strength Properties Of Engineered Wood Panels Using Real-Time Industrial Data, Timothy Mark Young

Doctoral Dissertations

The forest products industry is undergoing unprecedented change from international competition, increasing fiber costs, rising energy prices and falling product prices. Competitive businesses have the key ability to adapt quickly to change through improved knowledge. Among adaptations to change are better product development, improved process efficiency and superior product quality. This dissertation is directly related to improving the knowledge of forest products manufacturers by investigating data mining (DM) methods that improve the ability to quantify causality of sources of variation. A contemporary DM method related to decision theory is decision trees (DTs). DTs are designed for heterogeneous data and are …

Physical Properties Of Unconventional Superconductors, Valentina Anatolyevna Kuznetsova

Doctoral Dissertations

In the following development, we attempt to obtain basic physical properties of majority of unconventional superconductors through a Bardeen-Cooper-Schrieffer-type weak-coupling approach. The method we adopted in our study is model-independent. The weak-coupling approach depends only on the symmetry of the coupling, not on its origin. It is known that a general analysis of physical properties of unconventional superconductors is possible, but has not been done yet. The goal of our work is to develop and test such analysis, using available experimental data.

Since paramagnetic limiting for spin-singlet superconductors can be suppressed in superconductors with broken inversion symmetry of crystal lattice, …

Towards Automatic And Adaptive Optimizations Of Mpi Collective Operations, Jelena Pjesivac-Grbovic

Doctoral Dissertations

Message passing is one of the most commonly used paradigms of parallel programming. Message Passing Interface, MPI, is a standard used in scientific and high-performance computing. Collective operations are a subset of MPI standard that deals with processes synchronization, data exchange and computation among a group of processes. The collective operations are commonly used and can be application performance bottleneck. The performance of collective operations depends on many factors, some of which are the input parameters (e.g., communicator and message size); system characteristics (e.g., interconnect type); the application computation and communication pattern; and internal algorithm parameters (e.g., internal segment size). …

Efficacy Of Cognitive Therapy And Pharmacotherapy In Depression: A Meta-Analysis, Daniel B. Michel

Loma Linda University Electronic Theses, Dissertations & Projects

A meta-analysis comparing the long-term effectiveness of cognitive behavioral therapy (CBT) and pharmacotherapy in preventing relapse following treatment discontinuation was performed using published studies of depressed participants. Twenty-three articles met inclusionary criteria and were included in the analyses. Weighted effect sizes and moderators, treatment type, were calculated using statistical analysis software. Initially, fixed effects models were applied to the data, but due to significant between-group heterogeneity that could not be fully explained by treatment type, mixed effect models were used to account for the residual heterogeneity. Results indicated that overall, depressed individuals treated to remission with CBT evidence decreased relapse …

Histopathological Assessment And Comparison Sedimentation And Phosphate Stress On The Staghorn Coral, Acropora Cervicornis, Erin Christine Hodel

HCNSO Student Theses and Dissertations

Traditional coral reef monitoring efforts lack assessment of coral health at tissue and cellular levels. This thesis investigated tissue, cellular, and gross morphological responses of the Caribbean staghorn coral, Acropora cervicornis, to elevated sedimentation and phosphate using state-of-the-art histological techniques. Branch fragments of A. cervicornis were collected offshore Broward County, FL, acclimated for 12 weeks, subjected to a 4-week experimental period, and given a 1-week recovery period in laboratory aquaria. Treatments consisted of high doses (200 mg cm^-2 day^-1) of sedimentation (S), phosphate (4 μM) (P), and a combination of these two (S + P), in …

Alkoxide Routes To Inorganic Materials, George Harrison Thomas

Doctoral Dissertations

An all alkoxide solution chemistry utilizing metal 2-methoxyethoxide complexes in 2-methoxyethanol was used to deposit thin-films of metal oxides on single-crystal metal oxide substrates and on biaxially textured metal substrates. This same chemistry was used to synthesize complex metal oxide nanoparticles. Nuclear Magnetic Resonance spectroscopy was used to study precursor solutions of the alkaline niobates and tantalates. Film crystallization temperatures were determined from X-ray diffraction patterns of powders derived from the metal oxide precursor solutions. Film structure was determined via X-ray diffraction. Film morphology was studied using scanning electron microscopy (SEM) and atomic force microscopy (AFM).

Epitaxial thin-films of strontium …

Route Validation Using Radio Frequency Identification, William T. Watson

Theses and Dissertations

In recent years, radio frequency identification (RFID) has been proposed and implemented in a variety of applications where tracking objects, animals or people is desirable. This paper proposes a novel approach to the application of RFID tech- nology in those applications where it is possible to validate a person or an object's passive contact with a given or arbitrary set of fixed points along a predefined route. The notable departure from the typical application of RFID technology is that in this scheme, the transponders are permanently installed while the interrogator is affixed to a person or object that travels the …

Effects Of Environmental Stress On Growth, Yield, And Flavonolignan Content In Milk Thistle Silybum Marianum L. Gaertn, Amy Renae Belitz

Masters Theses

Four experiments were performed in a greenhouse or growth chamber to study the quantity and quality of flavonolignans in response to environmental stress in milk thistle (Silybum marianum L., Gaertn.). A preliminary experiment was conducted in spring 2004 to study effects of leaf harvests on growth, development, and flavonolignan content in milk thistle seeds. Taxifolin, a component of silymarin and precursor to flavonolignans, was significantly reduced due to leaf harvest treatments.

The weedy nature (sporadic germination) of Silybum made germinating enough plants for experimentation problematic. Initial germination studies to determine imbibition and pre-chilling requirements were inconclusive due to heavy …

Design Construction And Use Of A Thermomechanical Detwinning Apparatus: Detwinning Of Orthorhombic Nb2bacu2o3, Chad J. Bircher

Masters Theses

In this thesis I will describe a device designed and built for thermo- mechanically detwinning crystals. Twinning is a process in which a crys- talline structrure with two different axes of nearly equal length alternate directions throughout the material, effectively generating a single bulk material with two or more distinct internal crystals. This structure defect can lead to many other effects in the crystal, and it is useful to elimi- nate twinning in many materials in order to determine which properties are fundamental properties of the crystal, and which properties are ar- tifacts of the structural imperfections. The apparatus described …

Reduction Of Human Factors-Related Accidents During The Flight Test Of Homebuilt Aircraft Through The Application Of Professional Flight Test Practices, Justin Samuel Garr

Masters Theses

Homebuilt aircraft have a high accident rate during the flight test period, particularly during their first and second flights. For the 2002-2004 period, over 1.0% of homebuilt aircraft were involved in an accident on their first flight, and 3.3% were involved in accidents in the first 40 hours of operation. Untrained, low time in aircraft type amateur flight test participants, unorthodox flight test procedures, and lack of clear guidance as to who should and how to conduct safe and effective flight test lead to unsafe conditions and the accident statistics support this hypothesis. In the accidents analyzed, lack of experience …

Characterization Of The Temperature Dependence Of Optical Components In A Cryo-Vacuum Chamber Used For Space Sensor Testing, Jesse M. Labello

Masters Theses

The space sensor cryo-vacuum chambers at Arnold Air Force Base are world class sensor characterization and calibration facilities. The chambers provide a simulated deep space background and accurate infrared projections. Several large optical systems are used within the chambers to accomplish this. Calibration of the chambers requires the use of a database of the measured optical properties of these components to simulate the output. However, as the information in the database is room temperature information and the chambers run near 20K, some discrepancies exist between the actual output and the model output. The purpose of this work is to translate …

Major And Trace-Element Chemistry Of Minerals In Lithologies A And B In Martian Meteorite Eeta79001: Petrogenesis Revisited, Michael Joseph Mellin

Masters Theses

EETA79001 is a unique shergottite composed of two mafic lithologies (termed LithA and LithB) that are separated by an igneous contact. Both lithologies have basaltic compositions; however, LithA contains megacrysts of olivine, orthopyroxenes, and chromite whereas LithB does not; also, LithA is finer-grained than LithB. Currently, the literature is in disagreement regarding the formation of this unique meteorite, especially regarding LithA. Different formational theories (e.g. fractional crystallization, magma mixing, assimilation, and impact melting) have their own constraints (chemical, thermal, or petrographic). This study uses petrographic observations combined with major- and trace- element compositions within minerals to investigate the petrogenesis of …