Digital Commons Network^™

Ethnic Identity And Perceived Discrimination As Predictors Of Academic Attitudes: The Mediating And Moderating Roles Of Psychological Distress And Self-Regulation, Hui Chu

University of Kentucky Master's Theses

The current study addressed the deficiency in research by examining risk factors for immigrant children that may lead to academic disengagement (such as ethnic discrimination by peers and teachers, and psychological distress) and resilience factors that promote academic engagement (such as the development of a positive ethnic identity). Children who had stronger, more positive ethnic identities had more positive academic attitudes. Furthermore, the more the children were teased by their peers and graded unfairly by their teachers because of their ethnicity, the more they thought school was less important, less useful and felt less efficacious about school and valued school …

Power Of Inhibition Activity Screening And 3d Molecular Modeling Approaches In Hdac 8 Inhibitor Design, Gamze Bora Tatar, Tenzi̇le Deni̇z Tokluman, Kemal Yelekçi̇, Hayat Yurter

Turkish Journal of Chemistry

In-vitro inhibition activity screening and in-silico 3D molecular modeling approaches are important tools for design and development of specific histone deacetylase (HDAC) inhibitors. The objective of this study was to investigate the consistency between these 2 approaches. The HDAC 8 inhibition activities of 8 randomly selected different carboxylic acid derivatives were screened and in-vitro experimental results were compared with in-silico molecular modeling calculations. This study demonstrated that there is no sole gold standard technique for inhibitor design, and it was concluded that a combination of molecular modeling and activity screening assays will ensure more comprehensive and dependable results.

Conceptualizing And Improving Red Wine Grape Cultivars Grown In Kentucky, Matthew Simson

University of Kentucky Master's Theses

Wine sensory attributes are associated with quality of wines. Cabernet Franc did not possess good coloration of its wine. Therefore, in the 2009 and 2010 growing seasons, studies including the sampling of four red wine grape cultivars from the end of flowering throughout the rest of the season and applying treatments to Cabernet Franc grapevines at veraison were commenced to address suitability and color enhancement, respectively. The study examining Cabernet Franc, Cabernet Sauvignon, Chambourcin, and Norton looked at sampling their grapes at two-week intervals from times post-flowering to understand the demands of each cultivar during key stages of berry development, …

Effect Of A Silicon Tip On Absorption Cross Section, Field Enhancement, And Localized Surface Plasmon Resonance Of Different Sized Gold Nanoparticles Under Evanescent Wave Illumination, Gazi Mostafa Huda

University of Kentucky Master's Theses

We have numerically investigated the influence of a nanoscale silicon tip in proximity to an illuminated gold nanoparticle. We describe how the position of the high-permittivity tip and the size of a nanoparticle impact the absorption, peak electric field and surface plasmon resonance wavelength under different illumination conditions. We detail the finite element method (FEM) approach we have used for this, whereby we specify a volume excitation field analytically and calculate the difference between this source field and the total field (i.e., scattered-field formulation). We show that a nanoscale tip can locally enhance the absorption of the particle as well …

Examining Gender Differences In Persistence In Higher Education Among African American Students, Yvonne Townsend

University of Kentucky Master's Theses

This Study examined issues related to persistence in higher education among African American students, using the prominent model proposed by Vincent Tinto. The intentions were to examine the growing gender gap among African American students. The study examines factors from the Tinto model such as high school GPA, College GPA, college social integration and academic integration to try and explain the effects of gender among African American students. This research also attempts to elaborate the Tinto model by considering high school extracurricular activities as a pre-entry attribute that has an effect on persistence in higher education. Use of the Tinto …

Synthesis, Characterization, And Photoluminescence Properties Of Cu(Ii), Co(Ii), Ni(Ii), And Zn(Ii) Complexes Of N-Aminopyrimidine-2-Thione, Zülbi̇ye Önal, Hüseyi̇n Zengi̇n, Mehmet Sönmez

Turkish Journal of Chemistry

This research concentrates on the preparation, characterization, and photoluminescence properties of new Co(II), Ni(II), Cu(II), and Zn(II) complexes of N-aminopyrimidine-2-thione. The ligand and metal complexes were characterized by elemental analysis and spectroscopic studies such as IR, UV/Vis, API-ES, NMR, fluorescence, and magnetic susceptibility measurements. The ligand and the resulting metal complexes gave intense emissions (\lambda_{max} = 408 nm) upon irradiation by ultraviolet light. The photoluminescence quantum yields and long excited-state lifetimes of the ligand and its complexes were calculated. The ligand had photoluminescence quantum yields of 36% and long excited-state lifetimes of 3.40 ns. The photoluminescence intensities and quantum yields …

On Simple But Hard Random Instances Of Propositional Theories And Logic Programs, Gayathri Namasivayam

University of Kentucky Doctoral Dissertations

In the last decade, Answer Set Programming (ASP) and Satisfiability (SAT) have been used to solve combinatorial search problems and practical applications in which they arise. In each of these formalisms, a tool called a solver is used to solve problems. A solver takes as input a specification of the problem – a logic program in the case of ASP, and a CNF theory for SAT – and produces as output a solution to the problem. Designing fast solvers is important for the success of this general-purpose approach to solving search problems. Classes of instances that pose challenges to solvers …

Partially Halogenated Acenes And Heteroacenes For Organic Electronics, Balaji Purushothaman

University of Kentucky Doctoral Dissertations

Inorganic materials have dominated electronic applications such as photovoltaic cells, thin film transistors (TFTs) and light emitting diodes (LEDs). However developments in the field of organic electronics over the past three decades have enabled the use of organic materials in these devices. While significant improvements have been made to improve their electronic properties there are several road blocks towards commercial application. One of the significant obstacles is the poor charge carrier mobility associated with organic semiconductors processed by well established printing methods. The goal of my research project is to improve the charge carrier mobility of solution cast films of …

Analyzing Educational Attainments And Occupational Outcomes Of Tibetan Refugees Living In India, Tenzin Palkyi

University of Kentucky Master's Theses

Opportunities of mass education are a relatively new phenomenon in the Tibetan community. Following the incidents of 1959, the Dalai Lama and thousands of Tibetans fled into India. Mass education was implemented and sustained within the Tibetan community for the first time. The goal of this exploratory research is to study the impact of mass education on the first generations of Tibetans who experienced it in exile. This study analyzes the gendered pattern in subjects students choose to pursue, their educational attainment and the kinds of jobs they assume after graduation. The study presents a quantitative analysis of data spanning …

Novel Solution Processable Acceptors For Organic Photovoltaic Applications, Ying Shu

University of Kentucky Doctoral Dissertations

The field of organic electronics has become an increasingly important field of research in recent years. Organic based semiconductors have the potential for creating inexpensive, solution processed devices on flexible substrates. Some of the applications of organic semiconductors include organic field effect transistors, organic light emitting diodes and organic photovoltaics.

Functionalized pentacenes have been proven to be viable donor materials for use in organic photovoltaic devices. The goal of this research is to synthesize and test the viability of novel electron deficient pentacenes and pentacene based materials as acceptors to be used as drop-in replacements for PCBM in bulk-heterojunction organic …

A Classification Of Lower Paleozoic Carbonate-Bearing Rocks For Geotechnical Applications, Bethany L. Overfield

University of Kentucky Master's Theses

An empirically-based classification of lower Paleozoic carbonate-bearing rocks was created for field-based geotechnical applications. Geotechnical parameters were subsequently correlated to that classification. Seven hundred seventy-seven samples were used as the basis for the classification. Thirteen categories based on visual and tactile properties and a hydrochloric acid test were created. Samples were from central, north-central, and south-central Kentucky and represented the majority of Ordovician exposures in the state, and some Mississippian exposures. Few Silurian and Devonian units were included in the sample set. Geotechnical parameters, including density as well as elastic constants (shear and compression wave velocities, Poisson’s ratio, Young’s modulus, …

Analysis Of Student & Teacher Outcomes From Pre-Existing Data Obtained Through The Low Incidence Initiative: Teaching Academic Age-Appropriate Learning Via Communication Project, April M. Holman

University of Kentucky Master's Theses

Students with significant cognitive disabilities frequently exhibit reduced communicative and academic competence. The Low Incidence Initiative (LII) project was a professional development model designed to train school-based teams to facilitate increased communicative and academic competence with such students via distance-technology coaching. This study analyzed pre-existing data from year one of the LII. Data were analyzed to determine effectiveness of the project on communication status of students and on training school personnel to accurately identify student levels of communication, and for overall satisfaction with the project. Results indicated that all student participants demonstrated improvement in expressive communication output. 100% of students …

Investigation Of The Toxicity And Efflux Of Polychlorinated Biphenyls And Hydroxylated Polychlorinated Biphenyls In Escherichia Coli, Shen Geng

University of Kentucky Master's Theses

Polychlorinated biphenyls (PCBs) are persistent organic pollutants. Due to their properties, PCBs accumulate in the food-chain and post a threat to the health of human beings and wildlife. Hydroxylated PCBs (OH-PCBs) are oxidative metabolites of PCBs and are more hydrophilic than their parent PCBs. One of the best approaches to break down these contaminants is through bioremediation, which is an environmental friendly process that uses microorganisms to restore natural environment.

Towards this goal, we have investigated the toxicity and accumulation of PCBs and OH-PCBs in a Gram-negative bacterium, Escherichia coli. We have also determined the role played by a …

Comparison Of Digestive Function In Young And Mature Horses, Jennifer Elizabeth Earing

University of Kentucky Doctoral Dissertations

While forage plays an important role in equine nutrition, little research has been conducted evaluating fiber utilization by young horses. Therefore, studies were conducted to compare in vivo digestibility and digesta passage in weanlings and mature horses (Exp 1) and yearlings and mature horses (Exp 2). All horses were fed forage-based diets at the same rate (on a metabolic BW basis; Exp 1: 67% alfalfa cubes, 33% concentrate; Exp 2: 75% timothy cubes, 25% concentrate). Ytterbium labeled hay and cobalt-ethylenediaminetetraacetic acid were used to estimate digesta mean retention time (MRT), while in vivo digestibility (DM, OM, and NDF) was measured …

Some Contributions To The Censored Empirical Likelihood With Hazard-Type Constraints, Yanling Hu

University of Kentucky Doctoral Dissertations

Empirical likelihood (EL) is a recently developed nonparametric method of statistical inference. Owen’s 2001 book contains many important results for EL with uncensored data. However, fewer results are available for EL with right-censored data. In this dissertation, we first investigate a right-censored-data extension of Qin and Lawless (1994). They studied EL with uncensored data when the number of estimating equations is larger than the number of parameters (over-determined case). We obtain results similar to theirs for the maximum EL estimator and the EL ratio test, for the over-determined case, with right-censored data. We employ hazard-type constraints which are better able …

Experimental Flow Visualization For Corrugated Airfoils At Low Reynolds Number Including Development Of A Pitch And Plunge Fixture, Jeremy Ryan Sparks

University of Kentucky Master's Theses

Micro Air Vehicles (MAV’s) have small size and extreme maneuverability which makes them ideal for surveillance. Propulsion mechanisms include propellers, rotors, and flapping airfoils. Flapping motions, along with biologically-inspired wing profiles, are of interest due to their use of natural physics. Corrugated airfoil structures appears to have poor aerodynamic performance at higher Reynolds numbers, but serve well at Re<10,000. Understanding flow structures around corrugated profiles and comparing them to a standard airfoil will aid in understanding how these corrugated profiles perform well and have been adopted by some of nature’s most acrobatic flyers. Motivation for this investigation is to compare static flow visualizations of corrugated profiles to a standard National Advisory Committee for Aeronautics (NACA) airfoil from low to high angles of attack and further observe flow structure development of a pitching and plunging flat plate at a Re<10,000 and a Strouhal number relevant to natural fliers. The static visualization was conducted at Re=1,000 with a NACA 0012 airfoil and two corrugated models. The Pitch and Plunge Fixture (PPF) developed was constructed by simplifying flapping wings as a two degree of freedom motion in plunge (translation) and pitch (rotation). Results obtained from the PPF were compared with a numerical simulation.

A Reliability-Based Routing Protocol For Vehicular Ad-Hoc Networks, James Bernsen

University of Kentucky Master's Theses

Vehicular Ad hoc NETworks (VANETs), an emerging technology, would allow vehicles to form a self-organized network without the aid of a permanent infrastructure. As a prerequisite to communication in VANETs, an efficient route between communicating nodes in the network must be established, and the routing protocol must adapt to the rapidly changing topology of vehicles in motion. This is one of the goals of VANET routing protocols. In this thesis, we present an efficient routing protocol for VANETs, called the Reliable Inter-VEhicular Routing (RIVER) protocol. RIVER utilizes an undirected graph that represents the surrounding street layout where the vertices of …

Convergence Of Eigenvalues For Elliptic Systems On Domains With Thin Tubes And The Green Function For The Mixed Problem, Justin L. Taylor

University of Kentucky Doctoral Dissertations

I consider Dirichlet eigenvalues for an elliptic system in a region that consists of two domains joined by a thin tube. Under quite general conditions, I am able to give a rate on the convergence of the eigenvalues as the tube shrinks away. I make no assumption on the smoothness of the coefficients and only mild assumptions on the boundary of the domain.

Also, I consider the Green function associated with the mixed problem on a Lipschitz domain with a general decomposition of the boundary. I show that the Green function is Hölder continuous, which shows how a solution to …

Fate Of Stable Isotope Label During Predation Of 15N-Tagged Wild-Type Escherichia Coli By Protozoa, Ashley M. Barton

University of Kentucky Master's Theses

Currently, bacterial movement in karst aquifers is not well understood. Use of stable isotopes to label non-pathogenic Escherichia coli as a particulate groundwater tracer in karst systems has been examined in previous studies. Loss of the stable isotope signal is anticipated in traces greater than 500 m in length. Potential loss of ¹⁵N due to predation by protozoa was examined. Filter-sterilized water from Royal Spring in Georgetown, Kentucky, was inoculated with a mixture of either Tetrahymena pyriformis or Colpoda steinii and ¹⁵N-enriched E. coli and stored in the dark at 14°C. Samples were analyzed for their nitrogen isotope …

Microneedle-Assisted Transdermal Delivery Of Naltrexone Species: In Vitro Permeation And In Vivo Pharmacokinetic Studies, Mikolaj Milewski

University of Kentucky Doctoral Dissertations

Naltrexone (NTX) is a drug used primarily in the management of alcohol dependence and opioid dependence. Based on several drawbacks associated with the oral and injectable intramuscular dosage forms of naltrexone currently available on the market, there is substantial interest in delivering naltrexone transdermally. Although naltrexone does not permeate skin at the rate sufficient to reach therapeutic plasma concentrations in humans, novel flux enhancement methods such as microneedles help address this challenge. Earlier work in humans has demonstrated that the use of microneedles achieves plasma concentrations in the lower end of expected therapeutic values. Further flux enhancement is desired to …

Determining Interstellar Reddening: A New Approach Using Spectroscopy And Photometry, Syed A. Uddin

University of Kentucky Master's Theses

The mystery of Canis Major overdensity is addressed. We discuss concurrent methods and their limitations on the determination of interstellar reddening. We establish a new way to determine line of sight interstellear reddening by observing stellar spectral lines and UBV colors. We observe and analyze spectra of 22 stars in different open clusters. We find that Hydrogen Balmer line at 4861 angstrom can predict the stellar atmospheric parameters and intrinsic colors with reasonable accuracy. Comparing with observed colors we derive the reddening of the stars. We compare our results with standard database WEBDA and find that within 90% probability limit …

Perch Landing Maneuvers And Control For A Rotating-Wing Mav, Jonathan Louis Lubbers

University of Kentucky Master's Theses

This thesis addresses flight control of the perch landing maneuver for micro-aerial vehicles. A longitudinal flight model is constructed for a pigeon-sized aircraft. In addition to a standard elevator control surface, wing-rotation also considered as a non-standard actuator for increasing low-speed aerodynamic braking. Optimal state and control trajectories for the perch landing maneuver are computed using commercial software. A neighboring optimal control law is then developed and implemented in a set of flight simulations. Simulations are run with both a quasisteady and an unsteady aerodynamic model. The effectiveness of wing rotation and of the neighboring optimal control law is discussed, …

Physical Conditions In A Galactic Star Forming Region W22, Akshaya Rane

University of Kentucky Master's Theses

This document describes study of an active star forming region in our galaxy (the Milky Way) known as W22. Physical conditions in these regions can help us in understanding star formation processes in the universe and hence the structure and evolution of the universe. Zeeman effect measurements in 18 cm OH absorption line were carried out in order to estimate the line of sight magnetic field strength in the molecular cloud associated with this star forming region. Other physical parameters such as hydrogen column density, optical depth, critical magnetic field were also determined from these measurements. The region was mapped …

Solution Phase And Membrane Immobilized Iron-Based Free Radical Reactions: Fundamentals And Applications For Water Treatment, Scott Romak Lewis

University of Kentucky Doctoral Dissertations

Membrane-based separation processes have been used extensively for drinking water purification, wastewater treatment, and numerous other applications. Reactive membranes synthesized through functionalization of the membrane pores offer enhanced reactivity due to increased surface area at the polymer-solution interface and low diffusion limitations. Oxidative techniques utilizing free radicals have proven effective for both the destruction of toxic organics and non-environmental applications. Most previous work focuses on reactions in the homogeneous phase; however, the immobilization of reactants in membrane pores offers several advantages. The use of polyanions immobilized in a membrane or chelates in solution prevents ferric hydroxide precipitation at near-neutral pH, …

Connections, Paths, And Explanations - A Social Network Approach To Investigating Experiences Of Early Childhood Special Education With The Ecls-K, Kathryn Shirley Akers

University of Kentucky Doctoral Dissertations

The purpose of this study is to demonstrate a practical application of social network analysis in the field of education using a large-scale data source. Using the Early Childhood Longitudinal Base Year data, a network is identified by examining the connections that occur between supports, both inside and outside formal special education resources for kindergarteners with access to special education programs.

Social network mappings and quantitative findings are presented for formal and informal supports and primary disability category, along with policy implications and suggestions for further research. Findings indicate that social network analysis offers a unique and innovative perspective to …

Modeling And Optimization To Evaluate Sustainability Performance Of Customizable Product Service Systems, Ken Harsha Tilakaratne Wijekoon

University of Kentucky Master's Theses

The aim of this thesis is to present a new methodology to evaluate and optimize sustainability of customizable product-service systems while ensuring economic, environmental and societal constraints are also satisfied. Activities across the total product lifecycle are considered to develop a model that evaluates closed-loop flow, while being monitored through the growth, maturity and decline stages of the product to provide a comprehensive analysis. A novel method to evaluate the customer satisfaction is also presented. The research considers a modular product where customization can be achieved by selecting from alternatives while ensuring the compatibility between these alternatives. A manufacturer will …

Gauge-Gravity Duality And Its Applications To Cosmology And Fluid Dynamics, Jae-Hyuk Oh

University of Kentucky Doctoral Dissertations

This thesis is devoted to the study of two important applications of gauge-gravity duality: the cosmological singularity problem and conformal fluid dynamics. Gauge-gravity duality is a concrete dual relationship between a gauge theory (such as electromagnetism, the theories of weak and strong interactions), and a theory of strings which contains gravity. The most concrete application of this duality is the AdS/CFT correspondence, where the theory containing gravity lives in the bulk of an asymptotically anti-de-Sitter space-time, while the dual gauge theory is a deformation of a conformal field theory which lives on the boundary of anti-de-Sitter space-time(AdS).

Our first application …

Constructing The Real: The New Photography Of Crewdson, Gursky And Wall, Melissa A. Schwartz

University of Kentucky Master's Theses

A new class of photographs that relies on digital processes, best exemplified by the works of Gregory Crewdson, Andreas Gursky and Jeff Wall all exhibit a ‘not quite right’ quality that calls into question some of the most closely held truisms of photographic thought. Through novel technological processes combined with the elements of the new photography—new scale, fabulist imagery, and implied narrative—these images challenge the nature of photography as a documentary process and, beyond that, the nature of what we understand to be ‘the real’ that is supposedly documented. A visual analysis of these images through the lens of Roland …

The Behavior Of Nanothermite Reaction Based On Bi2o3/Al, L. Wang, D. Luss, Karen S. Martirosyan

Physics & Astronomy Faculty Publications

We studied the impact of aluminum particle size and the thickness of surrounding alumina layer on the dynamic pressure discharge of nanothermite reactions in the Bi2O3/Al system. A pressure discharge from 9 to 13 MPa was generated using as-synthesized Bi2O3 nano-particles produced by combustion synthesis and Al nanoparticles with size from 3 μm to 100 nm. The maximum reaction temperature was measured to be ∼2700 °C. The estimated activation energy of the reaction was 45 kJ/mol. A very large (several orders of magnitude) difference existed between the rate of the pressure pulse release by nanothermite reactions and by thermite …

Unidirectional Invisibility Induced By Pt-Symmetric Periodic Structures, Zin Lin, Hamidreza Ramezani

Physics & Astronomy Faculty Publications

Parity-time (PT) symmetric periodic structures, near the spontaneous PT-symmetry breaking point, can act as unidirectional invisible media. In this regime, the reflection from one end is diminished while it is enhanced from the other. Furthermore, the transmission coefficient and phase are indistinguishable from those expected in the absence of a grating. The phenomenon is robust even in the presence of Kerr nonlinearities, and it can also effectively suppress optical bistabilities.