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Electron Field-Emission From Carbon Nanotubes For Nanomachining Applications, Jaime A. Sanchez

University of Kentucky Doctoral Dissertations

The ability to pattern in the nanoscale to drill holes, to draw lines, to make circles, or more complicated shapes that span a few atoms in width is the main driver behind current efforts in the rapidly growing area of nanomanufacturing. In applications ranging from the microprocessor industry to biomedical science, there is a constant need to develop new tools and processes that enable the shrinking of devices. For this and more applications, nanomanufacturing using electron beams offers a window of opportunity as a top-down approach since electrons, unlike light, have a wavelength that is in the order of the …

Role Of Dipoles In The Bulk Phosphor Layer In The Electroluminance Mechanisms Of A.C. Thin Film Electroluminescent Display Devices, Praveen Kumar Sivakumar

University of Kentucky Doctoral Dissertations

The purpose of this dissertation is to advance the understanding of SrS-based a. c. thin film electroluminescent (ACTFEL) devices. The role of traps in the bulk phosphor layer in the light emission mechanism from ACTFEL devices is studied, characterized and modeled.

Experiments were performed to observe the response of the ACTFEL devices to tailored voltage excitations. A physical model was developed to describe the optoelectronic processes taking place in the phosphor; analytical equations were written and numerically simulated to plot the flux and luminance responses of the device to similarly tailored voltage excitations.

The voltage excitation parameters such as amplitude, …

Algebraic And Combinatorial Properties Of Certain Toric Ideals In Theory And Applications, Sonja Petrovic

University of Kentucky Doctoral Dissertations

This work focuses on commutative algebra, its combinatorial and computational aspects, and its interactions with statistics. The main objects of interest are projective varieties in Pⁿ, algebraic properties of their coordinate rings, and the combinatorial invariants, such as Hilbert series and Gröbner fans, of their defining ideals. Specifically, the ideals in this work are all toric ideals, and they come in three flavors: they are defining ideals of a family of classical varieties called rational normal scrolls, cut ideals that can be associated to a graph, and phylogenetic ideals arising in a new and increasingly popular area of …

Mechanistic Investigations Of The Trans Excision-Splicing And Trans Insertion-Splicing Reaction, Perry Patrick Dotson Ii

University of Kentucky Doctoral Dissertations

Group I intron-derived ribozymes are catalytic RNAs that have been engineered to catalyze a variety of different reactions, in addition to the native self-splicing reaction. One such ribozyme, derived from a group I intron of Pneumocystis carinii, can modify RNA transcripts through either the excision or insertion of RNA sequences. These reactions are mediated through the trans excision-splicing (TES) or trans insertionsplicing (TIS) reaction pathways. To increase our current understanding of these reactions, as well as their general applicability, a mechanistic and kinetic framework for the TES reaction was established. Furthermore, additional ribozymes were investigated for their ability to …

Precision Measurements Of The Neutron Electric Form Factor At High Momentum Transfers, Ameya Suresh Kolarkar

University of Kentucky Doctoral Dissertations

The neutron, although electrically neutral, is composed of elementary charged particles and as a result, possesses a charge distribution within. The charge distribution can be studied by measuring a quantity called the neutron electric form factor, Gⁿ_E. Experiment E02-013 at Jefferson Lab’s Hall A measured Gⁿ_E at high four-momentum transfer values of Q2 = 1.2, 1.7, 2.5 and 3.4 (GeV/c)² in double polarized semi-exclusive ³He(e, e'n) scattering in quasi-elestic kinematics by measuring the transverse asymmetry A_T of the cross section.

The neutron electric form factor is essential to …

The Mobility Of Fecal Indicator Microorganisms Within A Karst Groundwater Basin In The Inner Bluegrass Region, Kentucky, James Wade Ward

University of Kentucky Doctoral Dissertations

This project implemented novel approaches to assess the source, age, concentration and mobility of fecal indicator microorganisms within a karst groundwater system. Research was conducted in the well-characterized Blue Hole Spring karst groundwater basin in Versailles, Woodford County, Kentucky. At this site the AC/TC ratio and fecal coliform (FC) bacteria counts were used to delineate sources of fecal inputs and determine relative age of the fecal matter. An aging experiment using indicator bacteria (total coliform (TC) and atypical colonies (AC)), which approximated subsurface conditions, indicated that changes in the AC/TC ratio are likely to be retarded during bacterial transport through …

Algebraic Properties Of Edge Ideals, Rachelle R. Bouchat

University of Kentucky Doctoral Dissertations

Given a simple graph G, the corresponding edge ideal I_G is the ideal generated by the edges of G. In 2007, Ha and Van Tuyl demonstrated an inductive procedure to construct the minimal free resolution of certain classes of edge ideals. We will provide a simplified proof of this inductive method for the class of trees. Furthermore, we will provide a comprehensive description of the finely graded Betti numbers occurring in the minimal free resolution of the edge ideal of a tree. For specific subclasses of trees, we will generate more precise information including explicit formulas for …

Design, Synthesis, And Pharmacological Evaluation Of A Series Of Novel, Guanidine And Amidine-Containing Neonicotinoid-Like Analogs Of Nicotine: Subtype-Selective Interactions At Neuronal Nicotinic-Acetylcholine Receptor., Aaron Joseph Haubner

University of Kentucky Doctoral Dissertations

The current project examined the ability of a novel series of guandine and amidine-containing nicotine analogs to interact with several native and recombinantlyexpressed mammalian neuronal nicotinic-acetylcholine receptor (nAChR) subtypes. Rational drug design methods and parallel organic synthesis was used to generate a library of guanidine-containing nicotine (NIC) analogs (AH compounds). A smaller series of amidine-containing nicotine analogs (JC compounds) were also synthesized. In total, >150 compounds were examined. Compounds were first assayed for affinity in a high-throughput [³H]epibatidine radioligand-binding screen. Lead compounds were evaluated in subtype-selective binding experiments to probe for affinity at the α₄β_{2 …}

Ecosystem Restoration In The Ouachita National Forest: Evaluating The Pragmatism Of Pre-European Settlement Benchmarks, John Lawrence Davenport

University of Kentucky Doctoral Dissertations

This paper looks at the intersections of nature and culture through a study of forest ecosystem restoration efforts in the Ouachita National Forest (Arkansas and Oklahoma). Ecosystem restoration goals are often informed by a pre-European settlement (PES) condition, with an implicit (and occasionally explicit) assertion that such conditions are both more natural than and preferable to the contemporary state. In many cases resuming pre-suppression fire regimes remains a key mechanism for achieving this restored condition. This study’s three main objectives include: (1) determining how PES benchmarks arose in restoration thought, (2) examining how the choice to use a PES benchmark …

Studies Of Low-Lying States In 94zr Excited With The Inelastic Neutron Scattering Reaction, Esmat Elhami

University of Kentucky Doctoral Dissertations

The aim of nuclear structure studies is to observe and describe the structures and associated symmetries in nuclei, which in turn help us in understanding the nature of nucleon-nucleon interactions in a nucleus as a many-body quantum system. The protons and neutrons as constituents of a nucleus and their interactions are responsible for nuclear properties. The evolution of nuclear structure as a function of valence nucleon number, i.e., the number of nucleons beyond a magic number, can be inferred from the experimental level scheme and transition rates. In particular, the studies of low-lying, low-spin excited states in stable nuclei provide …

Efficient And Scalable Network Security Protocols Based On Lfsr Sequences, Saikat Chakrabarti

University of Kentucky Doctoral Dissertations

The gap between abstract, mathematics-oriented research in cryptography and the engineering approach of designing practical, network security protocols is widening. Network researchers experiment with well-known cryptographic protocols suitable for different network models. On the other hand, researchers inclined toward theory often design cryptographic schemes without considering the practical network constraints. The goal of this dissertation is to address problems in these two challenging areas: building bridges between practical network security protocols and theoretical cryptography. This dissertation presents techniques for building performance sensitive security protocols, using primitives from linear feedback register sequences (LFSR) sequences, for a variety of challenging networking applications. …

Charge Density Wave Polarization Dynamics, Luis Alejandro Ladino Gaspar

University of Kentucky Doctoral Dissertations

We have studied the charge density wave (CDW) repolarization dynamics in blue bronze (K_0.3MoO₃) by applying symmetric bipolar square-wave voltages of different frequencies to the sample and measuring the changes in infrared transmittance, proportional to CDW strain. The frequency dependence of the electro-transmittance was fit to a modified harmonic oscillator response and the evolution of the parameters as functions of voltage, position, and temperature are discussed. We found that resonance frequencies decrease with distance from the current contacts, indicating that the resulting delays are intrinsic to the CDW with the strain effectively flowing from the contact. …

Benzene-1,3-Diamidoethanethiol (Bdeth2) And Its Metal Compounds, Kamruz Md Zaman

University of Kentucky Doctoral Dissertations

There is a global need to find a permanent and readily implemented solution to the problem of heavy metal pollution in aqueous environments. A dithiol compound, benzene-1,3-diamidoethanethiol (BDETH₂), also known as N,N'-bis(2-mercaptoethyl) isophthalamide or N,N'-bis(2-mercaptoethyl)-1,3-benzenedicarboxamide, capable of binding divalent metal ions, has been synthesized and characterized. A broad range of BDET-metal compounds, spanning the periodic chart, has been prepared and characterized by IR, MS, EA, Raman, XAFS and TGA. The characteristics of the BDET-M compounds were determined through secondary reactions. In an effort to derivatize BDET-M compounds through alkylalumination a new cyclic compound, 1,3- bis(4,5-dihydrothiazolo)benzene, has …

Metabolite Analysis Of Clostridium Thermocellum Using Capillary Electrophoresis Based Techniques, Anup P. Thakur

University of Kentucky Doctoral Dissertations

Clostridium thermocellum is a thermophilic bacterium that converts biomass to ethanol directly; however, high sensitivity of this bacterium toward ethanol limits its commercial utility. To elucidate the effect of ethanol on the growth of this bacterium a metabolite analysis of C. thermocellum was performed. The hypothesis of the project was that exogenous ethanol alters the metabolite profile of C. thermocellum. For metabolite analysis, capillary electrophoresis-electrospray ionization-mass spectrometry method (CE-ESI-MS) was developed due to highly polar and charged nature of metabolites. To increase the sensitivity of CE-ESI-MS, several parameters at the ESI interface were optimized. The application of 50% isopropanol …

Accurate And Robust Preconditioning Techniques For Solving General Sparse Linear Systems, Eun-Joo Lee

University of Kentucky Doctoral Dissertations

Please download this dissertation to see the abstract.

New Silks Roads: Promises And Perils Of The Internet In The Thai Silk Industry, Mark Graham

University of Kentucky Doctoral Dissertations

The Internet is often touted as a panacea for perceived deficiencies in economic development. Its space-transcending abilities, which can instantly connect producers with consumers, have the potential to cut out intermediaries and to redistribute economic surplus in a more equitable manner. This dissertation asks whether the promises of the Internet are being realized in the Thai silk industry.

The project explores the following questions: (a) At which nodes in the commodity chain is the Internet being used?; (b) How has the introduction of the Internet altered production chains and the flows of capital in the Thai silk industry?; (c) How …

Application Of Linear Free Energy Relationships In The Prediction Of Triglyceride/Water Partition Coefficients And Lipid Bilayer Permeability Coefficients Of Small Organic Molecules And Peptides, Yichen Cao

University of Kentucky Doctoral Dissertations

Computational methods such as linear free energy relationships (LFERs) offer a useful high-throughput solution to quickly evaluate drug developability, e.g. membrane permeability, organic solvent/water partition coefficients, and solubility. LFERs typically assume the contribution of structural components/functional groups to the overall properties of a given molecule to be constant and independent. This dissertation describes a series of studies in which linear free energy relationships were developed to predict solvation of small organic molecules in lipid formulations, specifically, triglyceride containing solvents and phospholipid-based liposomes. The formation of intermolecular HBs in triglyceride solvents (homogenous with H-bond accepting ability) and intramolecular HBs within the …

Regulation Of L-Type Voltage-Dependnet Calcium Channels By The Rem Gtpase, Chunyan Pang

University of Kentucky Doctoral Dissertations

The Rem, Rem2, Rad, and Gem/Kir GTPases, comprise a novel subfamily of the small Ras-related GTP-binding proteins known as the RGK GTPases, and have been shown to function as potent negative regulators of high voltage-activated (HVA) Ca²⁺ channels upon overexpression. HVA Ca²⁺ channels modulate Ca²⁺ influx in response to membrane depolarization to regulate a wide variety of cellular functions and they minimally consist of a pore-forming α1 subunit, an intracellular β subunit, and a transmembrane complex α₂/δ subunit. While the mechanisms underlying RGK-mediated Ca²⁺ channel regulation remain poorly defined, it appears that both membrane …

A Systematic Study Of Thermodynamic And Transport Properties Of Layered CaN+1(Ru1-XCrX)NO3n+1, Vinobalan Durairaj

University of Kentucky Doctoral Dissertations

Orbital degrees of freedom play vital role in prompting novel phenomena in ruthenium based Ruddlesden-Popper compounds through coupling of orbits to spin and lattice. Physical properties are then particularly susceptible to small perturbations by external magnetic fields and/or slight structural changes. Current study pertains to the impact when a more-extended 4d Ruthenium ion is replaced by a less-extended 3d Chromium ion.

Perovskite CaRuO₃ (n=∞) is characterized by borderline magnetism and non- Fermi liquid behavior – common occurrences in quantum critical compounds. Remarkably, Cr substitution as low as x=0.05 abruptly drives CaRu_1−xCr_xO₃ from a paramagnetic …

Optimizing Learning Through Teacher-Student Relationships: A Test Of The Causal Process Student Understanding Model, Nicole Denise Dobransky

University of Kentucky Doctoral Dissertations

In many ways, higher educational systems in the United States are the most extraordinary in the world. Students come from all over to study in our institutes of higher learning. As our search for an explanation of how to facilitate student learning continues, the goal of this dissertation was to examine the heavily under-researched area of teacherstudent relationships as they relate to student understanding. Using the existing body of instructional communication research, the Student Understanding Model (SUM) is proposed and tested. Data collected from 302 undergraduate students was used to test the SUM. Results provide empirical support that relational messages …

Carbon Nanotube Supported Metal Catalysts For NoX Reduction Using Hydrocarbon Reductants, Eduardo Santillan-Jimenez

University of Kentucky Doctoral Dissertations

Nitrogen oxides (NO_x) are atmospheric pollutants that pose a serious threat to both the environment and human health. Although catalytic deNO_x technologies for engines working under stoichiometric air-to-fuel ratios (i.e., most gasoline engines) are already available, their performance is unsatisfactory under excess air conditions like those under which diesel engines operate.

The selective catalytic reduction of NO_x with hydrocarbon reductants (HC-SCR) is a potential deNO_xsolution for diesel engines, whose operating temperatures are 150-500 ºC. Given that is unlikely for a single catalyst to show acceptable activity throughout this entire temperature span, the use of …

Matrix Decomposition For Data Disclosure Control And Data Mining Applications, Jie Wang

University of Kentucky Doctoral Dissertations

Access to huge amounts of various data with private information brings out a dual demand for preservation of data privacy and correctness of knowledge discovery, which are two apparently contradictory tasks. Low-rank approximations generated by matrix decompositions are a fundamental element in this dissertation for the privacy preserving data mining (PPDM) applications. Two categories of PPDM are studied: data value hiding (DVH) and data pattern hiding (DPH). A matrix-decomposition-based framework is designed to incorporate matrix decomposition techniques into data preprocessing to distort original data sets. With respect to the challenge in the DVH, how to protect sensitive/confidential attribute values without …

Modular Fast Direct Analysis Using Non-Radiating Local-Global Solution Modes, Xin Xu

University of Kentucky Doctoral Dissertations

This dissertation proposes a modular fast direct (MFD) analysis method for a class of problems involving a large fixed platform region and a smaller, variable design region. A modular solution algorithm is obtained by first decomposing the problem geometry into platform and design regions. The two regions are effectively detached from one another using basic equivalence concepts. Equivalence principles allow the total system model to be constructed in terms of independent interaction modules associated with the platform and design regions. These modules include interactions with the equivalent surface that bounds the design region. This dissertation discusses how to analyze (fill …

Using Microhistological Techniques To Predict Botanical Composition Of Horse Diets On Cool-Season Grass Pasture, Jesse Ira Morrison

University of Kentucky Master's Theses

Microhistological analysis is a highly effective microscopic technique of determining botanical composition of animal diets by visual recognition of fecal plant fragments, and has been widely used in range studies. The objective of this study was to use microhistological techniques to predict the botanical composition of domesticated horse diets when grazing mixed cool-season pasture. Samples of tall fescue [Lolium arundinaceum (Schreb.) S.J. Darbyshire], Kentucky bluegrass (Poa pratensis L.) and orchardgrass (Dactylis glomerata L.) were evaluated for microscopically unique characteristics. Cool season pasture grazing studies were conducted in October 2006 and May 2007 in Lexington, KY. Eight thoroughbred mares were placed …

Data Assimilation And Visualization For Ensemble Wildland Fire Models, Soham Chakraborty

University of Kentucky Master's Theses

This thesis describes an observation function for a dynamic data driven application system designed to produce short range forecasts of the behavior of a wildland fire. The thesis presents an overview of the atmosphere-fire model, which models the complex interactions between the fire and the surrounding weather and the data assimilation module which is responsible for assimilating sensor information into the model. Observation plays an important role in data assimilation as it is used to estimate the model variables at the sensor locations. Also described is the implementation of a portable and user friendly visualization tool which displays the locations …

Assessing The Demand For Weather Index Insurance In Shandong Province, China, Lisha Zhang

University of Kentucky Master's Theses

Shandong Province, renowned as China’s greatest agricultural province, is dominated by smallholders growing rain-fed crops and vulnerable to severe weather shocks that can increase poverty rates. Weather index insurance, an innovative agricultural risk management product, may be an effective mechanism to address vulnerability to catastrophic weather risk in rural regions of China, including Shandong. This project evaluated current household livelihood and risk management strategies and farmer interest in weather index insurance. Data from 174 participants were collected using a methodology that included focus groups, questionnaires, and personal interviews. Despite limited access to formal financial services, Shandong farmers generally employ informal, …

The H-Vectors Of Matroids And The Arithmetic Degree Of Squarefree Strongly Stable Ideals, Erik Stokes

University of Kentucky Doctoral Dissertations

Making use of algebraic and combinatorial techniques, we study two topics: the arithmetic degree of squarefree strongly stable ideals and the h-vectors of matroid complexes.

For a squarefree monomial ideal, I, the arithmetic degree of I is the number of facets of the simplicial complex which has I as its Stanley-Reisner ideal. We consider the case when I is squarefree strongly stable, in which case we give an exact formula for the arithmetic degree in terms of the minimal generators of I as well as a lower bound resembling that from the Multiplicity Conjecture. Using this, we can …

Empirical Processes And Roc Curves With An Application To Linear Combinations Of Diagnostic Tests, Costel Chirila

University of Kentucky Doctoral Dissertations

The Receiver Operating Characteristic (ROC) curve is the plot of Sensitivity vs. 1- Specificity of a quantitative diagnostic test, for a wide range of cut-off points c. The empirical ROC curve is probably the most used nonparametric estimator of the ROC curve. The asymptotic properties of this estimator were first developed by Hsieh and Turnbull (1996) based on strong approximations for quantile processes. Jensen et al. (2000) provided a general method to obtain regional confidence bands for the empirical ROC curve, based on its asymptotic distribution.

Since most biomarkers do not have high enough sensitivity and specificity to …

The Influence Of Ca2+ Regulation In Synaptic Facilitation Of Motor Nerve Terminals In Crayfish And Drosophila As Well As In The Physiological Regulation Of Larval Drosophila Heart, Mohati Desai-Shah

University of Kentucky Doctoral Dissertations

Intracellular Ca²⁺ ions are highly regulated in animal cells for them to function normally. Since the tight regulation of [Ca²⁺]i is so ubiquitous among cells, it is not surprising that altered function in [Ca²⁺]i regulation is associated with a myriad of disease states in humans. This is particularly evident in pacing myocytes and nerve terminals related to synaptic transmission. A common thread through this dissertation is on the role of three regulators proteins that are common to many cell types. These are the plasmalemmal Na⁺/Ca²⁺ exchanger (NCX), the Ca²⁺-ATPase (PMCA) …

Colloid Mediated Transport Of Heavy Metals In Soils Following Reclamation With And Without Biosolid Application, Jarrod O. Miller

University of Kentucky Doctoral Dissertations

Soils disturbed by strip mining practices may have increased colloid loads moving to groundwater resources, also enhancing the transport of contaminants into our water resources. We hypothesize that contaminant transport within soils following mining is enhanced by colloid mobility. Two sites were chosen for this study, a 30-year old reclaimed strip mine in southwest Virginia and a recently mined area from eastern Kentucky. Intact reclaimed soil monoliths were retrieved from sandstone derived soils in southwestern Virginia. Reclaimed monoliths from eastern Kentucky were recreated in the lab. Intact undisturbed (native) soil monoliths representing the soils before mining were also sampled for …