Physical Sciences and Mathematics Commons^™

Phase Transitions And The Casimir Effect In Neutron Stars, William Patrick Moffitt

Masters Theses

What lies at the core of a neutron star is still a highly debated topic, with both the composition and the physical interactions in question. In this thesis, we made assumptions regarding the composition to further study the interactions of matter during the transition phases. These phases, also known as nuclear pasta, come from the unique physical conditions which occur within neutron stars. We examine the feasibility of the Casimir effect manifesting during these phases, as well as the effects it would have on the total energy of the system. We find that the crust-core transition cannot support the proper …

Avian Ecology During Oak Savanna And Woodland Restoration In The Mid-South, Christine Ann Henderson

Masters Theses

Disturbance-dependent ecosystems in the eastern United States have been declining since European settlement, and, in recent years, early-successional species have followed. My objective for this research was to determine if oak savanna and woodland restoration (i.e., overstory thinning and prescribed fire) was a viable method of recovering declining earlysuccessional species to the landscape of the Mid-South. At 3 sites, Catoosa Wildlife Management Area (CWMA; Tennessee), Green River Game Lands (GRGL; North Carolina), and Land Between the Lakes National Recreation Area (LBL; Tennessee), oak savanna and woodland restoration projects were established and maintained. Closed-canopy stands were thinned and a 2-year burn …

Developing Leading And Lagging Indicators To Enhance Equipment Reliability In A Lean System, Dhanush Agara Mallesh

Masters Theses

With increasing complexity in equipment, the failure rates are becoming a critical metric due to the unplanned maintenance in a production environment. Unplanned maintenance in manufacturing process is created issues with downtimes and decreasing the reliability of equipment. Failures in equipment have resulted in the loss of revenue to organizations encouraging maintenance practitioners to analyze ways to change unplanned to planned maintenance. Efficient failure prediction models are being developed to learn about the failures in advance. With this information, failures predicted can reduce the downtimes in the system and improve the throughput.

The goal of this thesis is to predict …

The Effect Of Plant Source On Lignin-Based Polyurethanes And The Interdiffusion Dynamics Of Semi-Rigid Polymers, Jason Michael Lang

Masters Theses

The work reported in this thesis increases our understanding of the effect of lignin plant source on the mechanical and morphological properties of lignin-based polyurethanes and the interdiffusion of glassy/liquid bilayer thin films. The interdiffusion of glassy/liquid polymer pairs has received much less attention than liquid/liquid bilayers, leading to conflicting results and unresolved discrepancies. Therefore, the reported study of interdiffusion between polysulfone glassy/liquid polymer layers provides insight into the dynamics of these systems.

This thesis first reports the correlation between the mechanical properties of lignin-based polyurethanes and the lignin plant source. Lignin is a molecule that can be used as …

Automated Program Profiling And Analysis For Managing Heterogeneous Memory Systems, Adam Palmer Howard

Masters Theses

Many promising memory technologies, such as non-volatile, storage-class memories and high-bandwidth, on-chip RAMs, are beginning to emerge. Since each of these new technologies present tradeoffs distinct from conventional DRAMs, next-generation systems are likely to include multiple tiers of memory storage, each with their own type of devices. To efficiently utilize the available hardware, such systems will need to alter their data management strategies to consider the performance and capabilities provided by each tier.

This work explores a variety of cross-layer strategies for managing application data in heterogeneous memory systems. We propose different program profiling-based techniques to automatically partition program allocation …

The Synthesis Of Memristive Neuromorphic Circuits, Austin Richard Wyer

Masters Theses

As Moores Law has come to a halt, it has become necessary to explore alternative forms of computation that are not limited in the same ways as traditional CMOS technologies and the Von Neumann architecture. Neuromorphic computing, computing inspired by the human brain with neurons and synapses, has been proposed as one of these alternatives. Memristors, non-volatile devices with adjustable resistances, have emerged as a candidate for implementing neuromorphic computing systems because of their low power and low area overhead. This work presents a C++ simulator for an implementation of a memristive neuromorphic circuit. The simulator is used within a …

A Gpu Implementation Of Distance-Driven Computed Tomography, Ryan D. Wagner

Masters Theses

Computed tomography (CT) is used to produce cross-sectional images of an object via noninvasive X-ray scanning of the object. These images have a wide range of uses including threat detection in checked baggage at airports. The projection data collected by the CT scanner must be reconstructed before the image may be viewed. In comparison to filtered backprojection methods of reconstruction, iterative reconstruction algorithms have been shown to increase overall image quality by incorporating a more complete model of the underlying physics. Unfortunately, iterative algorithms are generally too slow to meet the high throughput demands of this application. It is therefore …

A Predictive Model For Brook Trout Restoration In The Cherokee National Forest, Caylor Garrett Romines

Masters Theses

Over the course of the last century, Brook Trout (Salvelinus fontinalis) have been reduced in abundance and extirpated from many high elevation streams throughout the southern Appalachian Mountains. These fish have been threatened by anthropogenic factors that restrict their distribution across the longitudinal gradient of the streams they occupy. A large portion of Tennessee's Brook Trout streams are located within the Cherokee National Forest (CNF). Many agencies in the southern Appalachian Mountains are working to restore Brook Trout populations throughout this species’ historic native range. The purpose of this research is to develop a model of important habitat …

Classification Results Of Hadamard Matrices, Gregory Allen Schmidt

Masters Theses

In 1893 Hadamard proved that for any n x n matrix A over the complex numbers, with all of its entries of absolute value less than or equal to 1, it necessarily follows that

|det(A)| ≤ n^n/2 [n raised to the power n divided by two],

with equality if and only if the rows of A are mutually orthogonal and the absolute value of each entry is equal to 1 (See [2], [3]). Such matrices are now appropriately identified as Hadamard matrices, which provides an active area of research in both theoretical and applied fields …

Bats Roosting In Buildings In Great Smoky Mountains National Park: Ecology, Human Dimensions, And Management Implications, Kirstin Emily Fagan

Masters Theses

During summer, bats are regularly observed in buildings of Great Smoky Mountains National Park (GRSM or the Park), the most visited National Park in the USA. As a result, natural and cultural resources managers seek to ensure public safety and protect historic structures while minimizing impacts on bats, especially in light of declines in bat populations as a result of white-nose syndrome. To inform management decisions, I examined the ecological and human dimensions of bats roosting in buildings in GRSM.

To assess roost selection by building-roosting bats, I surveyed 140 buildings in the Park for bats during May to August, …

Convective Mode Climatology Of Tennessee Tornado Events And Effect On National Weather Service Warning Processes, Kelly Nicole Gassert

Masters Theses

Tennessee resides in the Southeastern United States, a region prone to violent tornadoes on a year-round basis. With one of the highest tornado fatality rates in the country, and a climatology that varies across the state, analysis of storms resulting in Tennessee tornadoes is necessary for improving forecasting techniques and decreasing loss of life. This study analyzed convective modes responsible for Tennessee tornadoes from 2003 to 2014 to determine an association with fatalities, seasonality, day and night, tornado magnitude, regionality, and multiple-tornado days. Chi-squared tests were conducted to determine if these patterns were significant. National Weather Service forecasters from the …

Characterization Of Reactor Background Radiation At Hfir For The Prospect Experiment, Blaine Alexander Heffron

Masters Theses

This work describes an investigation of the background radiation present at the High Flux Isotope Reactor (HFIR) on behalf of the PROSPECT collaboration. The PROSPECT experiment is designed to make a precision measurement of the antineutrino spectrum at HFIR and search for sterile neutrinos. Temporal and spacial variation of neutron and gamma backgrounds at the experiment site for the PROSPECT detector are measured in order to determine if the reactor correlated radiation will contribute a significant background to the inverse beta decay signal. Knowledge of spacial background variation will also be used to inform the design of a local shield …

On The Role Of Genetic Algorithms In The Pattern Recognition Task Of Classification, Isaac Ben Sherman

Masters Theses

In this dissertation we ask, formulate an apparatus for answering, and answer the following three questions: Where do Genetic Algorithms fit in the greater scheme of pattern recognition? Given primitive mechanics, can Genetic Algorithms match or exceed the performance of theoretically-based methods? Can we build a generic universal Genetic Algorithm for classification? To answer these questions, we develop a genetic algorithm which optimizes MATLAB classifiers and a variable length genetic algorithm which does classification based entirely on boolean logic. We test these algorithms on disparate datasets rooted in cellular biology, music theory, and medicine. We then get results from these …

Influence Of Algae On Soil Saturated Hydraulic Conductivity: An In Situ Treatment Option For Reducing Infiltration Beneath Unlined Algae Cultivation Ponds, Molly Brianne Pattullo

Masters Theses

Commercial production of algal biofuels is currently limited by high capital costs, including the cost of installation and maintenance of plastic pond liners, which mitigate seepage of cultivation fluids and control the release of salts and nutrients into the subsurface beneath outdoor algae cultivation ponds. However, studies of animal waste settling lagoons show that underlying soils ranging from sands to clay loams can exhibit reduced hydraulic conductivity within days to weeks after construction, reducing the need for plastic liners. The mechanisms of the hydraulic conductivity reductions, or “soil sealing”, are physical rearrangement of soil particles, buildup of fines, and the …

Development Of Nuclear Underground Engineered Test Surrogates For Technical Nuclear Forensics Exploitation, Robert Boone Gilbreath

Masters Theses

A method for formulation and production of Nuclear UnderGround Engineered Test Surrogates (NUGETS) based on notional improvised nuclear device (IND) detonations in an underground environment analogous to the Nevada National Security Site (NNSS) is presented. Extensive statistical analyses of precursory geochemical and geophysical characteristics are combined with an augmented surrogate debris cooling technique and predictive IND contributions from the ORIGEN Fallout Analysis Tool. Precursory and resultant elemental compositions, cooling curve calculations, and visual comparison of NUGETS to genuine underground debris are reported. Application of NUGETS methodology to future studies in urban, underground post-detonation technical nuclear forensic (TNF) analysis is suggested.

Spatially Explicit Population Estimates Of The Florida Black Bear, Jacob Michael Humm

Masters Theses

The Florida black bear (Ursus americanus floridanus) is currently comprised of 7 isolated subpopulations: Apalachicola, Eglin, Osceola, Ocala/St. Johns, Chassahowitzka, Highlands/Glades, and Big Cypress. The last statewide assessment of Florida black bear population dynamics was conducted by Simek et al. (2005) using traditional capture-markrecapture methods. The subspecies was removed from Florida’s List of State Threatened Species in 2012 contingent upon the formulation of a management plan that would maintain viable subpopulations of black bears in suitable habitat. Accurate population estimates for each of the remaining black bear subpopulations in Florida were needed to achieve the management goals of …

Development Of Microfluidic Platforms For Studies Of Cellular Organization In Escherichia Coli, Anna Dawn Jennings

Masters Theses

Traditionally, bacteria cells have been imaged on agarose pads allowing them to grow in steady conditions for only a few doubling times. To understand the cellular organization in bacteria, tools are needed that allow the observation of log-phase cells for many generations. In recent years, several microfluidic platforms have been designed that allow microscopic imaging of bacteria for over one hundred generations. One of the most promising approaches has been the so-called mother machine design where bacteria grow in small dead-end channels all connected to a large main channel, which is used to flow fresh nutrients to the cells and …

Influence Of Environmental Conditions And Inundation History On Bacterial Diversity Of Salt Marsh Soils In Southern Louisiana, Brandon M. Bagley

Masters Theses

Diversity patterns and controls on bacterial community composition were investigated from coastal salt marsh soils in southern Louisiana (USA) from 2012 – 2014. These salt marshes are part of an extensive coastal landscape that is experiencing land loss due to subsidence, sea-level rise, and anthropogenic activities, including from the impacts of the Deepwater Horizon oil spill in 2010. Prior to the oil spill, microbiology research focused predominately on biogeochemical roles and not on taxonomic representation in the soils or on understanding the significance of taxonomic diversity at the microbial level to marsh food webs or ecosystem dynamics. The purpose of …

Cation Exchange Processes Involving The Agricultural Antibiotic Tylosin In Soil And Soil Minerals, Jaime Jacinda Call

Masters Theses

Tylosin (TYL) is a veterinary antibiotic that is used as a feed additive in swine production. Concentrations as high as 4.0 mg L^-1 have been found in swine manure leachates. Tylosin is predominately a cationic species, due to the protonation of a dimethylamine moiety in pH < 7.5 solutions. The soil adsorption of TYL is influenced by pH, background electrolyte, and ionic strength, suggesting that ion exchange is an important retention mechanism. The objective of this study was to examine the exchange selectivity of TYL in competition with sodium and calcium in montmorillonite and vermiculite reference clays and in the Bt2 horizons of a west Tennessee Loring soil. Binary exchange studies were performed and exchange isotherms were developed to establish preference, to determine the Vanselow selectivity coefficient (K_V) as a function of exchange phase composition, and to determine the exchangeable and nonexchangeable forms of TYL. X-ray diffraction was used to evaluate TYL intercalation into reference and soil clay minerals. For TYLX-NaX exchange, the exchange isotherms indicated that TYL⁺ was preferred over Na⁺ by montmorillonite, but not by …

Efficient Simulation Of A Simple Evolutionary System, Mahendra Duwal Shrestha

Masters Theses

An infinite population model is considered for diploid evolution under the influence of crossing over and mutation. The evolution equations show how Vose’s haploid model for Genetic Algorithms extends to the diploid case, thereby making feasible simulations which otherwise would require excessive resources. This is illustrated through computations confirming the convergence of finite diploid population short-term behaviour to the behaviour predicted by the infinite diploid model. The results show the distance between finite and infinite population evolutionary trajectories can decrease in practice like the reciprocal of the square root of population size.

Under necessary and sufficient conditions (NS) concerning mutation …

Probing Pulse Structure At The Spallation Neutron Source Via Polarimetry Measurements, Connor Miller Gautam

Masters Theses

The Fundamental Neutron Physics Beamline (FNPB) at Spallation Neutron Source is used to probe fundamental forces via cold neutrons. The beamline's latest experiment is probing the hadronic weak interaction through the capture of polarized cold neutrons on ³He nuclei. While the strong nuclear force is dominant in this interaction, a weak signal can be observed in the parity violating momentum asymmetry in the reaction products. As the asymmetry measurement requires both neutron spin states, a means of controlling the neutron spin is required. In order to alternate the spins, a radio frequency spin rotator was installed for the experiment. …

Optimization Of The Nedm Experiment, Patrick Rogers

Masters Theses

The Neutron Electric Dipole Moment (NEDM) experiment is an upcoming experiment at ORNL to measure the size of an electric dipole moment inside of the neutron. This is being done to probe CP asymmetries that could give rise to a matter dominated universe. The experiment will utilize a nuclear reaction that outputs scintillation light in a manner that depends on the alignment of the spins of the reactant particles. This light will be detected and used to measure the NEDM. The amount of light collected for measurement will impact the accuracy of the results; the more photons collected the better …

Determining Sources Of Nitrate In The Semi-Arid Rio Grande Using Nitrogen And Oxygen Isotopes, Diego Alberto Sanchez Hernandez

Masters Theses

The Rio Grande, a semi-arid river in the American Southwest, is a major source of surface water for agriculture and drinking supplies in New Mexico and Texas. In addition to increasing salinity, considerable increases of NO₃^- [nitrate] have been observed in the semi-arid portion of the Rio Grande. It is possible that elevated water salinity inhibits denitrification on irrigated fields and, thus, fails to mediate excess nutrient load from anthropogenic activities. Therefore, two major goals of this project were to 1) characterize and quantify major NO₃^- sources, and 2) assess whether elevated water salinity affects microbial …