Physical Sciences and Mathematics Commons^™

Simulation And Phases Of Macroscopic Particles In Vortex Flow, Heath Eric Rice

Electronic Theses and Dissertations

Granular materials are an interesting class of media in that they exhibit many disparate characteristics depending on conditions. The same set of particles may behave like a solid, liquid, gas, something in-between, or something completely unique depending on the conditions. Practically speaking, granular materials are used in many aspects of manufacturing, therefore any new information gleaned about them may help refine these techniques. For example, learning of a possible instability may help avoid it in practical application, saving machinery, money, and even personnel. To that end, we intend to simulate a granular medium under tornado-like vortex airflow by varying particle …

Using Geophysics To Evaluate Levee Stability, Laura Mcconnell Dalton

Electronic Theses and Dissertations

Shallow slough slides have occurred along the river \side slope of Mississippi River Levees for over sixty years. Shallow slough slides also occur along smaller levees that protect tributaries of the Mississippi River. This investigation takes place along a section of the Coldwater River Levee, a tributary levee of the Mississippi River. Field observation, soil samples, and geophysical data were collected at two field sites located on the border of Tate and Tunica County, MS. The first site consists of a developed shallow slough slide that had occurred that has not yet been repaired and the second site is a …

Multidoman Piezo-Ceramic Cantilever, David Paul Sedorook

Electronic Theses and Dissertations

PZT-5H is a ferroelectric and piezoelectric material that has many applications that are the subjects of current research. As a ferroelectric, PZT-5H has a permanent electrical polarization that arises from ferroelectric domains. In this thesis, numerical simulations were conducted via the well know Finite Element Method of several types of piezoelectric cantilevers that were made of PIC-181, a high quality PZT-5H made in Germany. Single crystal cantilever models with multiple polarization vectors were investigated with Q factors ranging from Q = 50 to Q = 1200, where the acoustical displacements were calculated. Further, the displacements were calculated for a multidomain …

Elemental And Isotopic Analysis Of Sediments From Oxbow Lakes In The Mississippi Delta, Pragya Chakravarty

Electronic Theses and Dissertations

No abstract provided.

Comparison Of Apple's Ios 5 And Android For Mobile Applications Development: A Developer's Perspective, Estela Pochintesta

Electronic Theses and Dissertations

Body composition, or the proportion of fat, muscle, and bone of an individual's body, is an important indication of health status. Numerous techniques can be used to assess body composition, producing varied results and measurements. For individuals with insufficient or excessive amounts of body fat, accurate assessment of body composition is crucial. Two commonly used techniques for measuring body composition are air displacement plethysmography (adp) and dual-energy x-ray absorptiometry (dxa). Past research has been conducted, comparing adp and dxa, but the results are inconsistent. The majority of past studies found that, when compared to dxa, adp underestimated body fat percentage, …

Temporal And Spatial Assessment Of Pahs In Water, Sediment, And Oysters As A Result Of The Deepwater Horizon Oil Spill, Meghan Christina Dailey

Electronic Theses and Dissertations

On April 20, 2010, BP's Deepwater Horizon oil rig exploded leaking over 200 million gallons of crude oil into the Gulf of Mexico for 84 days. Exposure to oil-associated polycyclic aromatic hydrocarbons (PAHs) in the water and sediment could severely impact the aquatic organisms inhabiting the Gulf of Mexico (i.e. developmental defects, reproductive effects, death, etc.). Therefore, water, sediment and oyster, Crassostrea virginica, samples were collected approximately bimonthly between May 26 and November 30, 2010 from multiple sites along the Gulf Coast, namely, two sites in Mobile Bay (Denton and Sand Reefs at 1 or 0.1 m above the bay …

Restricting Supervised Learning: Feature Selection And Feature Space Partition, Xiaofei Nan

Electronic Theses and Dissertations

Many supervised learning problems are considered difficult to solve either because of the redundant features or because of the structural complexity of the generative function. Redundant features increase the learning noise and therefore decrease the prediction performance. Additionally, a number of problems in various applications such as bioinformatics or image processing, whose data are sampled in a high dimensional space, suffer the curse of dimensionality, and there are not enough observations to obtain good estimates. Therefore, it is necessary to reduce such features under consideration. Another issue of supervised learning is caused by the complexity of an unknown generative model. …

Optimization And Development Of In Vitro Bioassays To Determine Structure-Activity Relationships For Cannabinoid Receptor 1 And Cannabinoid Receptor 2, Afeef Husni

Electronic Theses and Dissertations

Cannabis has been around for thousands of years and has been used recreationally, medicinally, and for fiber. Over 400 compounds have been isolated from Cannabis sativa with approximately 100 being cannabinoids. Of those 100 compounds, Δ9-THC has been determined as the primary constituent, which is also responsible for the psychoactivity associated with Cannabis. Along with Δ9-THC, cannabidiol has been studied in depth for its therapeutic effects. This has currently been the focus of many researchers since cannabidiol does not cause psychotropic effects.

Cannabinoid receptors belong to the large superfamily of G protein-coupled receptors (GPCRs). Approximately 30% of marketed drugs target …

Theoretical And Spectroscopic Studies Of Molecular Systems For Charge Transfer And Energy Storage And Transfer, Debra Scardino

Electronic Theses and Dissertations

Efficient charge transfer and energy storage and transfer have become increasingly important in many areas of research and development. This is especially true for the development of optoelectronic devices, molecular electronics, and solar voltaic cells. Characterization of the photophysical properties of new molecular systems for these applications has emerged as an important field of research. Many molecular building blocks have been developed and understanding the properties of these systems at a fundamental level is essential for their successful implementation. This dissertation focuses on experimental and theoretical studies of some of these newly-developed molecular systems. Oxygen substituted dihydrobenzvalene is studied theoretically …

Stochastic Models For Evolutionary Genetic Problems, Wei Liao

Electronic Theses and Dissertations

Two stochastic models are designed for answering evolutionary genetic problems. The first study shows that inbreeding-environment interactions increase extinction risk. The second research demonstrates that 1) the carrying capacity and initial population growth rate is critical to determine the population persistence time; 2) increasing the advantageous mutation rate reduces the extinction risk although its effects are usually shadoby population size and fitness; 3) the new mutation correlation among environments rises during the evolution process, but it has compromised effects on population fate. Being able to accurately estimate the persistence time of populations of endangered plants and animals is central to …

Multi-Configurational Investigation Of Thermolytic Pathways Of Highly Strained Ring Systems, Jeffrey Dwayne Veals

Electronic Theses and Dissertations

The isomerization pathways of model high energy structures are of interest because of their relation to high energy density fuels. Electron resonance has been found to greatly affect the relative activation barriers for several isomerization pathways, and the major goal of this research is to accurately describe its role in determining the relative barriers for strain energy release pathways. This research is centered around the potential energy surfaces (PES's) for ? bond breaking and ? bond rotation in these highly strained structures. Of particular interest was how would resonance and or electronegativity affect the allowed/disallonature of the activation barriers in …

Use Of Georphysics To Map Subsurface Features At Levee Seepage Locaitons, Thomas Chapman Brackett

Electronic Theses and Dissertations

The Great Flood of 2011 caused moderate to severe seepage and piping along the Mississippi River levees in Northwest Mississippi. The aim of this thesis was to implement geophysical techniques at two seepage locations in order to give a better understanding of the causes of underseepage and information on how to mitigate the problem. Sites near Rena Lara in Coahoma County and near Francis in Bolivar County were chosen to conduct this survey. Electrical Resistivity Tomography (ERT) and Electromagnetic Induction (EM) surveys were conducted on and adjacent to levees to identify seepage pathways and any dominant geological features at the …

On The Nature Of Weak Intermolecular Forces: A First Principles Approach To Hydrogen Bonding And Pi-Type Interactions, Kari Lorene Copeland

Electronic Theses and Dissertations

Computational quantum chemistry is a branch of chemistry that is based on quantum mechanics. In this field, chemical phenomena is represented in mathematical form and computers are used to provide numerical solutions to rigorous mathematical equations. Through this medium, the properties of atoms and molecules are calculated with high accuracy. Chapter 1 opens with a general discussion of science, the development of atomic theory and computational chemistry. Electronic structure theory is more extensively reviein Chapter 2. Hydrogen bonding and dispersion forces are defined in Chapter 3, and the procedures used to computationally study these type interactions are considered. Chapter 4 …

Description Of Coherent Structures In The Atmospheric Boundary Layer By Model Reduction Of The Surface Pressure, Gregory William Lyons

Electronic Theses and Dissertations

The flow of coherent turbulent structures into a wind turbine is associated with vibrational blade excitation. Successful forecasting of such turbulent events for control system input would increase the lifetime of turbine components. The coherence of these features suggests description by model reduction. To this end, an array of pressure transducers was deployed on the ground at Reese Technology Center in Lubbock, Texas, and the pressure fluctuations were recorded over nearly two diurnal cycles. A program for computation of the dynamic mode decomposition was developed with special consideration for the case of a non-stationary, nonlinear system. A simulated surface-pressure perturbation …

Characterizations Of Zero Divisor Graphs Determined By Equivalence Classes Of Zero Divisors, Amanda Catherine Acosta

Electronic Theses and Dissertations

We study zero divisor graphs of commutative rings determined by equivalence classes of zero divisors, specifically for a Noetherian ring R. We study the classification of these graphs. Specifically, we add more criteria to the list of characterizations that disqualify a graph as the zero divisor graph of a ring. We also briefly discuss Sage, a mathematical software, which was an aid in providing visual pictures for the graphs under study.

Investigations Of Noncovalent Interactions Using Raman Spectroscopy And Electronic Structure Computations, Ashley Wright

Electronic Theses and Dissertations

This dissertation research focuses on the effects of noncovalent interactions on vibrational energy levels. Vibrational spectroscopy is a powerful tool for the study of the effects of weak intermolecular interactions such as hydrogen bonding and interactions with the environment, including solvation effects. Changes in the vibrational spectra of interacting molecules allow us to ascertain exactly which atoms and bonds are affected and to what extent they are affected. Quantum mechanical methods, ab initio theory and density functional theory, are employed to model molecular geometries, properties, and subtle interactions between molecules. Much of this research centers on the comparison of these …

Infrasound As Upper Atmospheric Monitor, Jelle Daniel Assink

Electronic Theses and Dissertations

Understanding and specification of the higher altitudes of the atmosphere with global coverage over all local times is hampered by the challenges of obtaining direct measurements in the upper atmosphere. Methods to measure the properties of the atmosphere above the stratopause is an active area of scientific research. In this thesis, we revisit the use of infrasound as a passive remote sensing technique for the upper atmosphere. Signals from the Tungurahua volcano in Ecuador are used to investigate the behavior of the upper atmosphere. Depending on the atmospheric conditions, stratospheric, mesospheric and thermospheric arrivals are observed during intervals of explosive …

Standoff Laser Interferometric Photoacoustic Spectroscopy For The Detection Of Explosives, Logan Marcus

Electronic Theses and Dissertations

There will unfortunately always be a pressing need to detect and identify explosive materials. Performing detection at a standoff distance is much safer and this is the impetus for this work. Photoacoustic spectroscopy is well suited to the task of explosive detection at a standoff distance. A detailed theory of the standoff measurement of the physical response of a system to photoacoustic excitation with an interferometric sensor has been constructed and tested. The use of this methodology to measure the standoff photoacoustic spectrum of TNT with an interferometric sensor has clearly been demonstrated. This methodology and the tested theory can …

On K-Trees And Special Classes Of K-Trees, John Wheless Estes

Electronic Theses and Dissertations

The class of k-trees is defined recursively as follows: the smallest k-tree is the k-clique. If G is a graph obtained by attaching a vertex v to a k-clique in a k-tree, then G is also a k-tree. Trees, connected acyclic graphs, are k-trees for k = 1. We introduce a new parameter known as the shell of a k-tree, and from the shell special subclasses of k-trees, tree-like k-trees, are classified. Tree-like k-trees are generalizations of paths, maximal outerplanar graphs, and chordal planar graphs with toughness exceeding one. Let fs = fs( G) be the number of independent sets …

Electrochemistry, Transport Properties And Electronic Spectroscopy Of Lanthanide Solutes In Bis(Trifluoromethylsulfonyl)Imide-Based Ionic Liquids, Yunfeng Pan

Electronic Theses and Dissertations

No abstract provided.

Tensor Products Of Vector Seminormed Spaces, John William Dever

Electronic Theses and Dissertations

A vector seminormed space is a triple consisting of a vector space, a Dedekind complete Riesz space, and a vector valued seminorm, called a vector seminorm, defined on the vector space and taking values in the Riesz space. The collection of vector seminormed spaces with suitably defined morphisms is shown to be a category containing finite products. A theory of vector seminorms on the tensor products of vector seminormed spaces is developed in analogy with the theory of tensor products of Banach spaces. Accordingly, a reasonable cross vector seminorm, or simply tensor seminorm, is defined such that a vector seminorm …

An Ssvep Brain-Computer Interface: A Machine Learning Approach, Fei Teng

Electronic Theses and Dissertations

A Brain-Computer Interface (BCI) provides a bidirectional communication path for a human to control an external device using brain signals. Among neurophysiological features in BCI systems, steady state visually evoked potentials (SSVEP), natural responses to visual stimulation at specific frequencies, has increasingly drawn attentions because of its high temporal resolution and minimal user training, which are two important parameters in evaluating a BCI system. The performance of a BCI can be improved by a properly selected neurophysiological signal, or by the introduction of machine learning techniques. With the help of machine learning methods, a BCI system can adapt to the …

The Legendre Transform Of The Holst Action, Caixia Gao

Electronic Theses and Dissertations

I start with a short introduction on 3+1 ADM form and the tetrad form of General Relativity, then I review the Legendre transform of the Einstein-Hilbert action and the Palatini action. The Holst action is a generalization of the Palatini action by including a topological term. I derive Ashtekar's connection form directly from this action by doing the Legendre transformation rather than by a canonical transformation in the usual phase space. This is done in both Remmanian signature with half-flat connection and Lorentz signature with general Barbero-Immirzi parameter.

Horizons, Holography And Hydrodynamics, Arif Mohd

Electronic Theses and Dissertations

In this dissertation we study black-hole horizons in general relativity and in Gauss-Bonnet gravity. We generalize Wald's "black-hole entropy is the Noether charge" construction to the first-order formalism of these theories. Next we construct the "membrane paradigm" for black objects in Gauss-Bonnet gravity and demonstrate how the horizon can be vieas a membrane with fluidlike properties. Holography is invoked to relate the transport coefficients obtained for the horizons in the membrane paradigm with the transport coefficients which describe the hydrodynamic limit of the boundary gauge theory.

Contributions To Robust Methods: Modified Rank Covariance Matrix And Spatial-Em Algorithm, Kai Yu

Electronic Theses and Dissertations

Classical multivariate statistical inference methods including multivariate analysis of variance, principal component analysis, factor analysis, canonical correlation analysis are based on sample covariance matrix. Those moment-based techniques are optimal (most efficient) under the normality distributional assumption. They are, however, extremely sensitive to outlying observations, susceptible to small perturbation in data and poor in the efficiency for heavy-tailed distributions. A straightforward treatment is to replace the sample covariance matrix with a robust one. Visuri et al. (2000) proposed a technique for robust covariance matrix estimation based on different notions of multivariate sign and rank. Among them, the spatial rank based covariance …

Donor-Sigma-Acceptor (D-Sigma-A) Molecules With Perylenebisimide Acceptors Having Alkyl Or Peg Swallowtails With Sulfur Or Hydroxyl Anchors: Synthesis And Applications In Langmuir-Blodgett Films, Single Molecule Spectroscopy (Sms), G-Quadruplex Studies And Passivation Of Gold Nanoparticles, Rajesh Kota

Electronic Theses and Dissertations

Use of single molecules as electronic devices is presently considered a potential alternative to semiconductor-based nanoscale electronics. The ability to study a single molecule or a small group of molecules provides a great opportunity to build electronic devices at the molecular level. It is vital to understand the parameters that control the device properties such as molecular structure, conformation and arrangement at the surface. Ari Aviram and Mark A. Ratner proposed the construction of a single organic molecule as an organic rectifier. Donor-Sigma-Acceptor (D-?-A ) molecules, when arranged with a proper orientation as Langmuir-Blodgett (LB) films and fixed between two …

Stratigraphy And Sedimentology Of The Smackover Formation, Southwest Alabama, Andrew Wilbourn

Electronic Theses and Dissertations

The Smackover Formation is a highly productive producer of hydrocarbons throughout the United States Gulf Coast region. More than four million barrels of oil and five billion cubic feet of gas have been produced from the Smackover Formation in the Barnett Field in southwest Alabama. Paleohighs formed during the Paleozoic and salt tectonic relief features control sediment distribution of the Smackover Formation in southwest Alabama. The Smackover in Barnett Field is entirely dolomitized, but the carbonate texture at the time of deposition is still visible in thin section. The Smackover carbonates in Barnett Field were deposited in the near-shore area …

Synthesis And Characterization Of Nickel Complexes With Relevance To Nickel Acireductone Dioxygenase And Nickel Superoxide Dismutase, Margo Nicole Montgomery

Electronic Theses and Dissertations

This research presents an investigation of synthetic model complexes with relevance to the active site of Ni(II) acireductone dioxygenase (Ni-ARD) and Ni(II) superoxide dismutase (Ni-SOD). Acireductone dioxygenases (ARDs) are a unique set of enzymes found in the methionine salvage pathway that catalyze the oxidation reaction of acireductone (1, 2-dihydroxy-3-oxo-5-(methylthio)pent-1-ene). These enzymes share a compolypeptide sequence but bind different metal ions, Ni2+ or Fe2+, at the active site. The Ni-ARD enzyme is responsible for the off pathway shunt in the pathway. Using the tridentate nitrogen donor ligands hydrotris(3,5-dimethyl-1-pyrazolyl)borate (Tp*) and the newly developed tris(1, 2-dimethyl-4-imadozyl)carbinol, (4-TICMe, Me) several reactions involving the …