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  Partner: UNT Libraries
 Decade: 2010-2019
 Collection: UNT Theses and Dissertations
Creating Community in Isolation: the History of Corpus Christi’s Molina Addition, 1954-1970
“Creating Community in Isolation: The History of Corpus Christi’s Molina Addition, 1954-1970” examines the history of the Molina Addition in Corpus Christi, Nueces County, Texas, and its serving district, the West Oso Independent School District, from 1954 to 1970. Specifically, this essay begins with an analysis of the elite-driven campaign to annex the blighted Molina Addition in September and October 1954. The city intended to raze the neighborhood and develop middle-class homes in place of the newly annexed neighborhood. Following the annexation of the Molina Addition, African American and ethnic Mexican residents initiated protracted struggles to desegregate and integrate schools that served their area, the West Oso Independent School District, as detailed in the chapter, “The West Oso School Board Revolution.” The chapter examines the electoral “revolution” in which Anglo rural elites were unseated from their positions on the school board and replaced by African American and ethnic Mexican Molina Addition residents. The third chapter, “Building Mo-Town, Texas,” focuses on residents’ struggle to install indoor plumbing, eliminate pit privies, construct paved roads, and introduce War on Poverty grants to rehabilitate the neighborhood. This chapter also offers a glimpse into the social life of Molina youth during the 1960s. digital.library.unt.edu/ark:/67531/metadc822818/
“No Paper Cowboys”: Stories
Equilibrium is paramount in the crafting of a story, and for every writer this sense of balance is different. The writer must manage a balance of showing and telling, of denotation and connotation, and forever strive to find the perfect word in both the denotative and connotative sense, so that the reader and writer can meeting in a living story—both in the ink on the page and the remaining white space. digital.library.unt.edu/ark:/67531/metadc822819/
Nonlinear and Quantum Optics Near Nanoparticles
We study the behavior of electric fields in and around dielectric and metal nanoparticles, and prepare the ground for their applications to a variety of systems viz. photovoltaics, imaging and detection techniques, and molecular spectroscopy. We exploit the property of nanoparticles being able to focus the radiation field into small regions and study some of the interesting nonlinear, and quantum coherence and interference phenomena near them. The traditional approach to study the nonlinear light-matter interactions involves the use of the slowly varying amplitude approximation (SVAA) as it simplifies the theoretical analysis. However, SVVA cannot be used for systems which are of the order of the wavelength of the light. We use the exact solutions of the Maxwell's equations to obtain the fields created due to metal and dielectric nanoparticles, and study nonlinear and quantum optical phenomena near these nanoparticles. We begin with the theoretical description of the electromagnetic fields created due to the nonlinear wavemixing process, namely, second-order nonlinearity in an nonlinear sphere. The phase-matching condition has been revisited in such particles and we found that it is not satisfied in the sphere. We have suggested a way to obtain optimal conditions for any type and size of material medium. We have also studied the modifications of the electromagnetic fields in a collection of nanoparticles due to strong near field nonlinear interactions using the generalized Mie theory for the case of many particles applicable in photovoltaics (PV). We also consider quantum coherence phenomena such as modification of dark states, stimulated Raman adiabatic passage (STIRAP), optical pumping in $4$-level atoms near nanoparticles by using rotating wave approximation to describe the Hamiltonian of the atomic system. We also considered the behavior of atomic and the averaged atomic polarization in $7$-level atoms near nanoparticles. This could be used as a prototype to study any $n-$level atomic system experimentally in the presence of ensembles of quantum emitters. In the last chapter, we suggested a variant of a pulse-shaping technique applicable in stimulated Raman spectroscopy (SRS) for detection of atoms and molecules in multiscattering media. We used discrete-dipole approximation to obtain the fields created by the nanoparticles. digital.library.unt.edu/ark:/67531/metadc822820/
Self-definition and College Adaptation in Students From the Ronald E Mcnair Postbaccalaureate Achievement Program
While a great deal of psychological research is conducted on college students, less has been done on their adaptation to college. These young adults, as they develop ego identity and differentiate themselves from parents and families, must adjust to the social and academic environment of college. Psychosocial adjustment predicts college retention better than academic predictors do. First generation college students face greater than typical challenges adapting to college. The Ronald E. McNair Post-Baccalaureate Achievement Program exists to aid first generation, lower income undergraduate student who wish to pursue a doctoral degree. Self-definition scored from thematic apperceptive technique stories reflects an individual’s relative freedom from social role constraint. This study examined the role of self-definition and familial understanding and acceptance in this population as predictors of successful adaptation to college. While neither was found to be a significant predictor, family understanding and acceptance was found to be a more defining characteristic of this sample than was self-definition. This suggests that when social support is sufficient, individuals do not need to rely on self-definition. digital.library.unt.edu/ark:/67531/metadc822821/
Accurate Energetics Across the Periodic Table Via Quantum Chemistry
Greater understanding and accurate predictions of structural, thermochemical, and spectroscopic properties of chemical compounds is critical for the advancements of not only basic science, but also in applications needed for the growth and health of the U.S. economy. This dissertation includes new ab initio composite approaches to predict accurate energetics of lanthanide-containing compounds including relativistic effects, and optimization of parameters for semi-empirical methods for transition metals. Studies of properties and energetics of chemical compounds through various computational methods are also the focus of this research, including the C-O bond cleavage of dimethyl ether by transition metal ions, the study of thermochemical and structural properties of small silicon containing compounds with the Multi-Reference correlation consistent Composite Approach, the development of a composite method for heavy element systems, spectroscopic of compounds containing noble gases and metals (ArxZn and ArxAg+ where x = 1, 2), and the effects due to Basis Set Superposition Error (BSSE) on these van der Waals complexes. digital.library.unt.edu/ark:/67531/metadc822822/
An Initial Study of Binary and Ternary Ti-based Alloys Manufactured Using Laser Engineered Net Shaping (Lenstm)
In this study an initial assessment of the composition – microstructure – property relationships in binary and ternary Ti – based systems are made possible using LENSTM technology. Laser Engineering Net Shaping (LENSTM), a rapid prototyping, directed laser deposition methodology of additive manufacturing (AM) was used to create bulk homogenous specimens that are compositionally graded. Compositionally graded specimens were made possible by incorporating elemental blends of powder during the LENSTM process. While there have been numerous studies assessing the influence of common elements (e.g., V, Mo, Al, and Cr) on the resulting microstructure in titanium alloys, other elements have been neglected. A systematic study of the Ti – Fe – Al ternary system based upon varying compositions of the eutectoid former, Fe with Al to stabilize the a and b phases respectively has also been neglected. This research effort focuses on exploiting the LENSTM process by rapidly assessing the composition – microstructure – property relationships in a combinatorial approach for the Ti – W, Ti – Fe, and Ti – Fe – Al systems. Compositionally graded specimens of Ti – xW (0<x<40wt.%(14.79at.%)), Ti – xFe (0<x<35wt.%(36.37at.%)), and Ti – xFe – yAl (0<x<40wt.%(36.37at.%)), y=5,10, 15wt.%) have been heat treated to also assess the influence of thermal history on microstructural features such as phase composition and volume fraction. Lastly, a Ti – xMo (0<x<40wt.%(24.96at.%)) compositionally graded specimen was deposited to re-assess the Mo-equivalency nature of W, as well as assess the role of phase separation in microstructural evolution at temperatures above and below the invariant point (~695°C) of the Ti – W binary system. digital.library.unt.edu/ark:/67531/metadc822823/
Effect of Alloy Composition, Free Volume and Glass Formability on the Corrosion Behavior of Bulk Metallic Glasses
Bulk metallic glasses (BMGs) have received significant research interest due to their completely amorphous structure which results in unique structural and functional properties. Absence of grain boundaries and secondary phases in BMGs results in high corrosion resistance in many different environments. Understanding and tailoring the corrosion behavior can be significant for various structural applications in bulk form as well as coatings. In this study, the corrosion behavior of several Zr-based and Fe-Co based BMGs was evaluated to understand the effect of chemistry as well as quenched in free volume on corrosion behavior and mechanisms. Presence of Nb in Zr-based alloys was found to significantly improve corrosion resistance due to the formation of a stable passive oxide. Relaxed glasses showed lower rates compared to the as-cast alloys. This was attributed to lowering of chemical potential from the reduced fraction of free volume. Potentiodynamic polarization and Electrochemical Impedance Spectroscopy (EIS) techniques helped in quantifying the corrosion rate and polarization resistance. The effect of alloy composition was quantified by extensive surface analysis using Raman spectroscopy, energy dispersive x-ray spectroscopy and auger spectroscopy. Pitting intensity was higher in the as-cast glasses than the relaxed glasses. The electrochemical behavior of a Zr-Ti-Cu-Ni-Be bulk metallic glass subjected to high strain processing was studied. High strain processing caused shear band formation and an increase in the free volume. Potentiodynamic polarization and EIS showed a strong correlation between the enthalpy of structural relaxation and corrosion rate and polarization resistance. Pitting was observed to preferentially occur on shear bands in the processed samples, while it was stochastic in unprocessed glass. The corrosion analysis of Co-Fe glasses showed an increase in corrosion current density when Fe content was increased from 0 to 7 at%. The corrosion resistance improved when Fe content was further increased to 15 at%. Similar trend was seen in EIS studies. The improved corrosion resistance at 15 at% Fe can be attributed to the large supercooled region that facilitates the formation of completely amorphous alloy, in contrast to lower Fe containing alloys, where short range ordering may deteriorate the corrosion resistance. Porous metallic glass structure was developed by electrochemical dealloying via cyclic voltammetry. Mechanical properties and changes in electrical conductivity were measured as a function of depth from surface by nano-indentation and nano electrical contact resistance technique. The nanoporous layer was found have hardness of 0.41 GPa and elastic modulus of nearly 22 GPa. The resistivity of the nanoporous layer continuously decreased when moving towards the substrate as the indentation depth increased which is attributed to the gradient in pore size. digital.library.unt.edu/ark:/67531/metadc822824/
A High-fat Meal Alters Post-prandial Mrna Expression of Sirt1, Sirt4, and Sirt6
Sirtuins (SIRT) regulate the transcription of various genes involved in the development of diet-induced obesity and chronic disease; however, it is unknown how they change acutely following a high-fat meal. The purpose of this study was to determine the effect of a high-fat meal (65% kcals/d; 85% fat recommendation), on SIRT1-7 mRNA expression in blood leukocytes at 1, 3, and 5-h post-prandial. Men and women (N=24) reported to the lab following an overnight fast (>12H). Total RNA was isolated and reverse transcribed prior to using a Taqman qPCR technique with 18S rRNA as a normalizer to determine SIRT1-7 mRNA expression. An additional aliquot of serum was used to measure triglycerides. Data was analyzed using a RM ANOVA with P<0.05. Triglycerides (P<0.001; 124%) peaked at 3-h. SIRT 1 (P=0.004; 70%), and SIRT 6 (P=0.017; 53%) decreased expression at 3-h. SIRT4 (P=0.024) peaked at 5H relative to baseline (70%) and 3-h (68%). To our knowledge, this is the first study to report that consumption of a high-fat meal transiently alters SIRT mRNA expression consistent in a pattern that mirrors changes in serum triglycerides. Decrease in expression of SIRT1 and SIRT6 combined with an increased SIRT4 would be consistent with an increase in metabolic disease risk if maintained on a chronic basis. digital.library.unt.edu/ark:/67531/metadc822825/
Parameter Estimation of Microwave Filters
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The focus of this thesis is on developing theories and techniques to extract lossy microwave filter parameters from data. In the literature, the Cauchy methods have been used to extract filters’ characteristic polynomials from measured scattering parameters. These methods are described and some examples are constructed to test their performance. The results suggest that the Cauchy method does not work well when the Q factors representing the loss of filters are not even. Based on some prototype filters and the relationship between Q factors and the loss, we conduct preliminary studies on alternative representations of the characteristic polynomials. The parameters in these new models are extracted using the Levenberg–Marquardt algorithm to accurately estimate characteristic polynomials and the loss information. digital.library.unt.edu/ark:/67531/metadc822826/
The Forty-fifth Illinois Volunteer Infantry Regiment: the Washburne Lead Mine Regiment in the Civil War
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Of the roughly 3,500 volunteer regiments and batteries organized by the Union army during the American Civil War, only a small fraction has been studied in any scholarly depth. Among those not yet examined by historians was one that typified the western armies commanded by the two greatest Federal generals, Ulysses S. Grant and William T. Sherman. The Forty-fifth Illinois Volunteer Infantry was at Fort Donelson and Shiloh with Grant in 1862, with Grant and Sherman during the long Vicksburg campaign of 1862 and 1863, and with Sherman in the Meridian, Atlanta, Savannah, and Carolinas campaigns in the second half of the war. These Illinois men fought in several of the most important engagements in the western theater of the war and, in the spring of 1865, were present when the last important Confederate army in the east surrendered. The Forty-fifth was also well connected in western politics. Its unofficial name was the “Washburne Lead Mine Regiment,” in honor of U.S Representative Elihu B. Washburne, who used his contacts and influences to arm the regiment with the best weapons and equipment available early in the war. (The Lead Mine designation referred to the mining industry in northern Illinois.) In addition, several officers and enlisted men were personal friends and acquaintances of Ulysses Grant of Galena, Illinois, who honored the regiment for their bravery in the final attempt to break through the Confederate defenses at Vicksburg. The study of the Forty-fifth Illinois is important to the overall study of the Civil War because of the campaigns and battles the unit participated and fought in. The regiment was also one of the many Union regiments at the forefront of the Union leadership’s changing policy toward the Confederate populace and war making industry. In this role the regiment witnessed the impact of President Abraham Lincoln’s Emancipation Proclamation. Of interest then, are the members’ views on the freeing of the slaves. Also of interest are their views on the arming of the slaves into black regiments, and on the Copperhead, anti-war movement in the Union. With ample sources on the regiment, and with no formal history of the unit having been written or published, a scholarly, modern study of the Lead Mine regiment therefore seems in order, as it would provide further insight into the Civil War from the Union soldiers’ perspective and into the sacrifices the men made in order to preserve their country. digital.library.unt.edu/ark:/67531/metadc822827/
Parent-adolescent Attachment, Bullying and Victimization, and Mental Health Outcomes
Traditional and cyber bullying have been identified as universal problematic issues facing adolescents, and research is needed to understand correlates associated with these phenomena. Structural equation modeling analyses examined associations between attachment to parents, traditional and cyber bullying or victimization, and mental health outcomes among 257 high school students (Average age 15.9 years). Key patterns emerged, including associations between maternal attachment and mental health outcomes; victimization and mental health concerns; and bullying and victimization in both traditional and cyber contexts. The role of attachment to mothers and fathers varied by context. Findings extend the literature by identifying risk factors in adolescence associated with bullying and victimization, as well as suggesting appropriate prevention and intervention strategies to increase adolescent well-being. digital.library.unt.edu/ark:/67531/metadc822828/
Deformation Micro-mechanisms of Simple and Complex Concentrated Fcc Alloys
The principal objective of this work was to elucidate the effect of microstructural features on the intrinsic dislocation mechanisms in two FCC alloys. First alloy Al0.1CoCrFeNi was from a new class of material known as complex concentrated alloys, particularly high entropy alloys (HEA). The second was a conventional Al-Mg-Sc alloy in ultrafine-grained (UFG) condition. In the case of HEA, the lattice possess significant lattice strain due to the atomic size variation and cohesive energy differences. Moreover, both the lattice friction stress and the Peierls barrier height are significantly larger than the conventional FCC metals and alloys. The experimental evidences, so far, provide a distinctive identity to the nature and motion of dislocations in FCC HEA as compared to the conventional FCC metals and alloys. Hence, the thermally activated dislocation mechanisms and kinetics in HEA has been studied in detail. To achieve the aim of examining the dislocation kinetics, transient tests, both strain rate jump tests and stress relaxation tests, were conducted. Anomalous behavior in dislocation kinetics was observed. Surprisingly, a large rate sensitivity of the flow stress and low activation volume of dislocations were observed, which are unparalleled as compared to conventional CG FCC metals and alloys. The observed trend has been explained in terms of the lattice distortion and dislocation energy framework. As opposed to the constant dislocation line energy and Peierls potential energy (amplitude, ΔE) in conventional metals and alloys, both line energy and Peierls potential undergo continuous variation in the case of HEA. These energy fluctuations have greatly affected the dislocation mobility and can be distinctly noted from the activation volume of dislocations. The proposed hypothesis was tested by varying the grain size and also the test temperature. Activation volume of dislocations was a strong function of temperature and increased with temperature. And the reduction in grain size did not affect the dislocation mechanisms and kinetics. This further bolstered the hypothesis. The second part deals with deformation characteristics of Al-Mg-Sc alloy. The microstructure obtained from the severe plastic deformation (SPD) techniques differ in dislocation density, grain/cell size, and in the grain boundary character distribution. Therefore, it is vital to understand the deformation behavior of the UFG materials produced by various SPD techniques, as the microstructural features basically control the deformation mechanisms. In this study, a detailed analysis was made to understand the deformation mechanisms operative in various regimes of a stress-strain in UFG Al-Mg-Sc alloy produced via friction stir processing. The stress-strain curves exhibited serrations from the onset of yielding to the point of sample failure. The serration amplitude and frequency was higher in UFG material as compared to CG material. Furthermore, the microstructural features that result in the serrated flow were investigated along with the avalanche characteristics. The presence of both ultrafine grains and Al3Sc precipitates were the necessary conditions to reach the critical stress required to push the grain boundary into a critical state to set off an avalanche. The microstructural conditions that did not satisfy both the requirements did not exhibit deep serrations. digital.library.unt.edu/ark:/67531/metadc822829/
Let Her Be Shorn: 1 Corinthians 11 and Female Head Shaving in Antiquity
In 1 Corinthians 11:3-15, Paul writes that if a woman is to be so immodest as to wear her hair uncovered while praying or prophesying in a Christian assembly she might as well shave her head. Paul instructs the Corinthians that it is “one and the same” for a woman to have her head shaved and for her to unveil her hair. There is a large body of works cataloging the modesty standards in Hellenistic Greece but Paul’s reference to head-shaving remains obscure. This thesis looks to find the best explanation of Paul’s instructions. Research in this topic began as an investigation of a popular modern view. It can be found in conversation or a simple Google search, that women in Ancient Greece with their head shaved were prostitutes. Beyond being prostitutes, they were probably temple prostitutes. The evidence does not bear this out as there is no artwork depicting prostitutes, or indeed any women, with their heads shaved. Instead prostitutes are shown in Greek erotic art with both long and short hair, some with and some without head coverings. Literary sources do offer several different examples of women who had their hair cut off. There are examples of women shaving their hair off in Lucian’s The Syrian Goddess, Tacitus’ Germania, Plutarch’s Lycurgus and Roman Questions, several Talmudic sources, and On Fortune II, formerly attributed to Dio Chrysostom. By examining these sources in tandem with 1 Corinthians 11, the most probable impetus behind Paul’s writing relates to punishments for adultery. digital.library.unt.edu/ark:/67531/metadc822830/
Identification of Hox Genes Controlling Thrombopoiesis in Zebrafish
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Thrombocytes are functional equivalents of mammalian platelets and also possess megakaryocyte features. It has been shown earlier that hox genes play a role in megakaryocyte development. Our earlier microarray analysis showed five hox genes, hoxa10b, hoxb2a, hoxc5a, hoxc11b and hoxd3a, were upregulated in zebrafish thrombocytes. However, there is no comprehensive study of genome wide scan of all the hox genes playing a role in megakaryopoiesis. I first measured the expression levels of each of these hox genes in young and mature thrombocytes and observed that all the above hox genes except hoxc11b were expressed equally in both populations of thrombocytes. hoxc11b was expressed only in young thrombocytes and not in mature thrombocytes. The goals of my study were to comprehensively knockdown hox genes and identify the specific hox genes involved in the development of thrombocytes in zebrafish. However, the existing vivo-morpholino knockdown technology was not capable of performing such genome-wide knockdowns. Therefore, I developed a novel cost- effective knockdown method by designing an antisense oligonucleotides against the target mRNA and piggybacking with standard control morpholino to silence the gene of interest. Also, to perform knockdowns of the hox genes and test for the number of thrombocytes, the available techniques were both cumbersome or required breeding and production of fish where thrombocytes are GFP labeled. Therefore, I established a flow cytometry based method of counting the number of thrombocytes. I used mepacrine to fluorescently label the blood cells and used the white cell fraction. Standard antisense oligonucleotide designed to the central portion of each of the target hox mRNAs, was piggybacked by a control morpholino and intravenously injected into the adult zebrafish. The thrombocyte count was measured 48 hours post injection. In this study, I found that the knockdown of hoxc11b resulted in increased number of thrombocytes and knockdown of hoxa10b, hoxb2a, hoxc5a, and hoxd3a showed reduction in the thrombocyte counts. I then screened the other 47 hox genes in the zebrafish genome using flow sorting method and found that knockdown of hoxa9a and hoxb1a also resulted in decreased thrombocyte number. Further, I used the dye DiI, which labels only young thrombocytes at specific concentrations and observed that the knockdown of hoxa10b, hoxb2a, hoxc5a, hoxd3a, hoxa9a and hoxb1a, lead to a decrease in young thrombocytes; whereas hoxc11b knockdown lead to increase in number of young thrombocytes. Using bromodeoxyuridine, I also showed that there is increase in release of young thrombocytes into peripheral circulation in hoxc11b knockdown fish which suggests that hoxc11b significantly promotes cell proliferation rather effecting apoptosis. In conclusion, I found six hox genes that are positive regulators and one hox gene is a negative regulator for thrombocyte development. digital.library.unt.edu/ark:/67531/metadc822768/
Messiaen’s Musical Language: Technique and Theological Symbolism in Les Corps Glorieux, “Combat De La Mort Et De La Vie”
One of the most important ways to understand Olivier Messiaen’s musical language is through the lens of the theological ideas that many of his works convey. He considers expressing his Christian faith to be the primary purpose in his music. Through his idiosyncratic technique, Messiaen gives power and life to his religious music that he combines with his interest in literature, musical analysis, poetic imagery and symbolism, his love for theatre, and his compositional and organ abilities. The abundant studies of Messiaen’s works deal with the intricacies of his musical language, yet most of these studies barely discuss his theological ideas. Nevertheless, technical analysis of his music poses immense challenges, especially in the domains of melody and harmony. Although my approach is unconventional and do not follow any existing system, I base my technical and theological analyses mainly from Messiaen's technique, his commentaries and his references to the Scriptures. The “Combat de la mort et de la vie” is the heart of Les Corps glorieux in both technical and theological aspects. It is an intricate musical artwork where Messiaen demonstrates his melodic and harmonic developments using his idiosyncratic language, and through symbolism portrays the most complex of all drama according to Christian theology—the story of Jesus Christ's Passion and Resurrection. My research can relate directly to a more informed and convincing performance of the work, and can contribute a different perspective to the study, understanding, and appreciation of Messiaen's theologically inspired works. digital.library.unt.edu/ark:/67531/metadc822769/
The Effect of Post-exercise Ethanol Consumption on the Acute Hormonal Response to Heavy Resistance Exercise in Women
The purpose of this study was to examine the hormonal response to acute ethanol ingestion following a bout of heavy resistance exercise in women. Eight resistance trained women completed two identical acute heavy resistance exercise tasks (AHRET). From 10-20 minutes post-AHRET, participants consumed either a grain ethanol or a placebo beverage. Blood was collected before (PRE) and immediately after the AHRET (IP) and then every 20 minutes for five hours. Blood collected after beverage ingestion was pooled into 3 batches (phases: 20-40 minutes, 60-120 minutes, and 140-300 minutes post-exercise) and analyzed for serum total testosterone (TT), free testosterone (FT), insulin-like growth factor-I (IGF-I), human growth hormone (GH), cortisol (COR), and estradiol (E2) concentrations. Circulating concentrations of TT were significantly greater at P20-40 than at PRE, P60-120, and P140-300. Circulating concentrations of FT were significantly greater at P20-40 than at all other times. Circulating concentrations of GH were significantly greater at IP than at PRE, P60-120, and P140-300. Circulating concentrations of COR were significantly greater at P20-40 than at all other times. Additionally, COR concentrations at P140-300 were significantly lower than at all other times. Circulating concentrations of IGF-1 were significantly greater at P20-40 than at P60-120 and P140-300. Circulating concentrations of E2 were significantly greater at P20-40 than at all other times. In summary, the present study demonstrated an acute modulation of the neuroendocrine milieu following a heavy resistance exercise bout in women. Ethanol ingestion appeared to have no significant effect on the characteristics of acute hormonal augmentation in TT, FT, GH, COR, IGF-1, or E2. digital.library.unt.edu/ark:/67531/metadc822770/
Characterization of Ti-6al-4v Produced Via Electron Beam Additive Manufacturing
In recent years, additive manufacturing (AM) has become an increasingly promising method used for the production of structural metallic components. There are a number of reasons why AM methods are attractive, including the ability to produce complex geometries into a near-net shape and the rapid transition from design to production. Ti-6Al-4V is a titanium alloy frequently used in the aerospace industry which is receiving considerable attention as a good candidate for processing via electron beam additive manufacturing (EBAM). The Sciaky EBAM method combines a high-powered electron beam, weld-wire feedstock, and a large build chamber, enabling the production of large structural components. In order to gain wide acceptance of EBAM of Ti-6Al-4V as a viable manufacturing method, it is important to understand broadly the microstructural features that are present in large-scale depositions, including specifically: the morphology, distribution and texture of the phases present. To achieve such an understanding, stereological methods were used to populate a database quantifying key microstructural features in Ti-6Al-4V including volume fraction of phases, a lath width, colony scale factor, and volume fraction of basket weave type microstructure. Microstructural features unique to AM, such as elongated grains and banded structures, were also characterized. Hardness and tensile testing were conducted and the results were related to the microstructural morphology and sample orientation. Lastly, fractured surfaces and defects were investigated. The results of these activities provide insight into the process-structure-properties relationships found in EBAM processed Ti-6Al-4V. digital.library.unt.edu/ark:/67531/metadc822771/
Culturally Proficient Leadership: Teacher Perceptions of Elementary School Principals in Urban, Title I Schools
This study examined elementary teachers’ perceptions of their principal’s level of cultural proficiency. Practices for Developing a Culturally Competent School Environment, a survey Camille Smith and adapted by Dr. Mack T. Hines, was completed from a sample size of 119 teachers. The survey contained 35 items, including six constructs: valuing diversity, assessing the culture, managing the dynamics of difference, institutionalizing cultural knowledge and resources, adapting to diversity and inclusiveness. Teachers rated their principal using a Likert scale which consisted of 1 = never uses, 2 = rarely uses, 3 = sometimes uses, 4 = frequently uses, and 5 = always uses. Teachers of various races, ages and years with their principal participated in this study. The study reveals that these variables do not make a statistically significant difference in the teachers’ perception of how proficient they are in valuing diversity, a assessing his/her own culture and institutionalizing cultural knowledge. This quantitative study reveals the variances of statistical significance of teacher demographics: age, gender, years served under current principal and accountability rating of the school. Cultural proficiency is important to the development and maintenance of the necessary relationships among students, teachers, principals and the school community. digital.library.unt.edu/ark:/67531/metadc822772/
Exploring Student Learning on a Short-term, Faculty-led Study Abroad Course Through a Student Development Lens
Embarking on a study abroad experience is thought to be a transformational experience for students, and previous researchers have tended to find that the potential benefits of study abroad experiences, including greater conceptual and behavioral intercultural competence, are greater with longer periods abroad. The purpose of this study was to create an intentional learning experience for students who embarked on a short-term study abroad in rural areas of China and to apply faculty intervention of a student development approach to student learning to create a high-impact learning environment for students centered on a service-learning project. This qualitative study gathered primary data from students and instructors during the course through a collection of observation and field notes, student journals, pre- and post-construct tests, and final presentation. Follow-up interviews were conducted 10 months after course completion. Six students participated in this course and study who were from a variety of disciplines and classifications. Five students were female; one was male. Four students were undergraduates; two were graduate students. Student ethnicities included three Caucasians and African American, along with two international students from Mexico and Iran. Key outcomes of this study were that when short-term study abroad faculty members applied creative interventions, students were transformed with regard to their beliefs, perspectives, and behaviors and that when they guided students through a process of reflection and analysis, students exhibited exponential personal development. In addition, the ability to challenge or support students in reaching higher levels of personal development is a privilege that faculty must earn over time and through an authentic demonstration of care for students’ wellbeing. Short-term study abroad faculty members can use the results of this study to maximize the developmental impact of such programs on student participants. digital.library.unt.edu/ark:/67531/metadc822773/
Biological Applications of a Strongly Luminescent Platinum (Ii) Complex in Reactive Oxygen Species Scavenging and Hypoxia Imaging in Caenorhabditis Elegans
Phosphorescent transition metal complexes make up an important group of compounds that continues to attract intense research owing to their intrinsic bioimaging applications that arise from bright emissions, relatively long excited state lifetimes, and large stokes shifts. Now for biomaging assay a model organism is required which must meet certain criteria for practical applications. The organism needs to be small, with a high turn-over of progeny (high fecundity), a short lifecycle, and low maintenance and assay costs. Our model organism C. elegans met all the criteria. The ideal phosphor has low toxicity in the model organism. In this work the strongly phosphorescent platinum (II) pyrophosphito-complex was tested for biological applications as a potential in vivo hypoxia sensor. The suitability of the phosphor was derived from its water solubility, bright phosphorescence at room temperature, and long excited state lifetime (~ 10 µs). The applications branched off to include testing of C. elegans survival when treated with the phosphor, which included lifespan and fecundity assays, toxicity assays including the determination of the LC50, and recovery after paraquat poisoning. Quenching experiments were performed using some well knows oxygen derivatives, and the quenching mechanisms were derived from Stern-Volmer plots. Reaction stoichiometries were derived from Job plots, while percent scavenging (or antioxidant) activities were determined graphically. The high photochemical reactivity of the complex was clearly manifested in these reactions. digital.library.unt.edu/ark:/67531/metadc822774/
The Countess of Counter-revolution: Madame Du Barry and the 1791 Theft of Her Jewelry
Jeanne Bécu, an illegitimate child from the Vaucouleurs area in France, ascended the ranks of the Ancien régime to become the Countess du Barry and take her place as Royal Mistress of Louis XV. During her tenure as Royal Mistress, Jeanne amassed a jewel collection that rivaled all private collections. During the course of the French Revolution, more specifically the Reign of Terror, Jeanne was forced to hatch a plot to secure the remainder of her wealth as she lost a significant portion of her revenue on the night of 4 August 1789. To protect her wealth, Jeanne enlisted Nathaniel Parker Forth, a British spy, to help her plan a fake jewel theft at Louveciennes so that she could remove her economic capital from France while also reducing her total wealth and capital with the intent of reducing her tax payments. As a result of the theft, her jewelry was transported to London, where she would travel four times during the French Revolution on the pretext of recovering her jewelry. This thesis examines her actions while abroad during the Revolution and her culpability in the plot. While traveling to and from London, Jeanne was able to move information, money, and people out of France. Jeanne was arrested and charged with aiding the counter-revolution, for which the Revolutionary Tribunal sentenced her to death. Madame du Barry represented the extravagance and waste of Versailles and of Bourbon absolutism, and this symbolic representation of waste was what eventually inhibited Jeanne’s success. digital.library.unt.edu/ark:/67531/metadc822775/
Small Town Retail Change in East Texas: an Analysis of Retail Growth, Decline, and Spatial Reconfiguration
In recent years, small towns have experienced declining levels of retail activity attributable to a variety of factors. Previously conducted research identifies a number of these factors such as changing population dynamics, continuously evolving retail practices, locational factors, and an assortment of other macroeconomic factors. Although retail decline is common for many small towns, there are some small towns that have been able to maintain their viability in an ever-changing economic climate. The primary purpose of this research is to better understand what spatial and socio-economic characteristics contribute to retail growth and decline in a series of small towns. This research highlights a selection of small towns across a 14 county area within east Texas. The selection of small towns includes a number of towns with an increasing number of retail establishments as well as a number of towns with decreasing retail establishments over the 14 year study timeframe. Contained within this research is a discussion of small town economic and retail development, as well as findings regarding spatial and socio-economic characteristics as they relate to retail growth and decline in small towns. This research finds that locational characteristics do have an effect on retail growth and decline. The research also supports the literature, which states retail growth and decline is more pronounced within certain retail categories. digital.library.unt.edu/ark:/67531/metadc822776/
Identification of Genes Involved in Flocculation by Whole Genome Sequencing of Thauera Aminoaromatica Strain Mz1t Floc-defective Mutants
Thauera aminoaromatica MZ1T, a floc-forming bacterium isolated from an industrial activated sludge wastewater treatment plant, overproduces exopolysaccharide (EPS) leading to viscous bulking. This phenomenon results in poor sludge settling and dewatering during the clarification process. To identify genes responsible for bacterial flocculation, a whole genome phenotypic sequencing technique was applied. Genomic DNA of MZ1T flocculation-deficient mutants were subjected to massively parallel sequencing. The resultant high-quality reads were assembled and compared to the reference genome of the wild type genome. We identified nine nonsynonymous mutations and one nonsense mutation putatively involved in EPS biosynthesis. Complementation of the nonsense mutation located in an EPS deacetylase gene restored the flocculating phenotype. The FTIR spectra of EPS isolated from the wild-type showed reduced C=O peak of the N-acetyl group at 1665 cm-1 as compared to the spectra of MZ1T floc-deficient mutant EPS, suggesting that the WT EPS was partially deacetylated. Gene expression analysis also demonstrated the deacetylase gene transcript increased before flocculation occurred. The results suggest that the deacetylation of MZ1T EPS is crucial for flocculation. The information obtained from this study will be useful for preventing viscous bulking and wastewater treatment system failure, and may have potential applications in the biotechnology sector for the controlled removal of cells. digital.library.unt.edu/ark:/67531/metadc822777/
Photo-induced Toxicity of Deepwater Horizon Spill Oil to Four Native Gulf of Mexico Species
The 2010 Deepwater Horizon oil spill resulted in the accidental release of millions of barrels of crude oil into the Gulf of Mexico (GoM). Photo-induced toxicity following co-exposure to ultraviolet (UV) radiation is one mechanism by which polycyclic aromatic hydrocarbons (PAHs) from oil spills may exert toxicity. Blue crab (Callinectes sapidus) are an important commercial and ecological resource in the Gulf of Mexico and their largely transparent larvae may make them sensitive to PAH photo-induced toxicity. Mahi-mahi (Coryphaena hippurus), an important fishery resource, have positively buoyant, transparent eggs. These characteristics may result in mahi-mahi embryos being at particular risk from photo-induced toxicity. Red drum (Sciaenops ocellatus) and speckled seatrout (Cynoscion nebulosus) are both important fishery resources in the GoM. They spawn near-shore and produce positively buoyant embryos that hatch into larvae in about 24 h. The goal of this body of work was to determine whether exposure to UV as natural sunlight enhances the toxicity of crude oil to early lifestage GoM species. Larval and embryonic organisms were exposed to several dilutions of water accommodated fractions (WAF) from several different oils collected in the field under chain of custody during the 2010 spill and two to three gradations of natural sunlight in a factorial design. Here, we report that co-exposure to natural sunlight and oil significantly reduced larval survival and embryo hatch compared to exposure to oil alone. digital.library.unt.edu/ark:/67531/metadc822778/
An Accelerometer-based Gesture Recognition System for a Tactical Communications Application
In modern society, computers are primarily interacted with via keyboards, touch screens, voice recognition, video analysis, and many others. For certain applications, these methods may be the most efficient interface. However, there are applications that we can conceive where a more natural interface could be convenient and connect humans and computers in a more intuitive and natural way. These applications are gesture recognition systems and range from the interpretation of sign language by a computer to virtual reality control. This Thesis proposes a gesture recognition system that primarily uses accelerometers to capture gestures from a tactical communications application. A segmentation algorithm is developed based on the accelerometer energy to segment these gestures from an input sequence. Using signal processing and machine learning techniques, the segments are reduced to mathematical features and classified with support vector machines. Experimental results show that the system achieves an overall gesture recognition accuracy of 98.9%. Additional methods, such as non-gesture recognition/suppression, are also proposed and tested. digital.library.unt.edu/ark:/67531/metadc822779/
Examination of Sexual Differences in the Acute Effects of Haloperidolon Licking
Schizophrenia is a debilitating psychiatric condition affecting almost one percent of the US population. Typical antipsychotics (e.g., haloperidol) have been in use for several decades and are generally very effective in treating the emotional and cognitive effects of schizophrenia, but are used as the last line of treatment due to their severe extrapyramidal motor side effects under chronic exposure. The present study was conducted to investigate the role of sex in determining the oromotor side effects of typical antipsychotics via measuring different behavioral dimensions of male and female Sprague-Dawley rats licking sucrose after haloperidol treatment. The results showed a stronger sensitivity in female rats than male rats within total licking responses and inter-lick intervals. The present results suggest closer attention needs to be paid to the role that sexual hormones play in the motor slowing and behavior-reducing effects of antipsychotics. digital.library.unt.edu/ark:/67531/metadc822780/
A Practical Edition of the Twenty-four Caprices for Solo Violin by Sir William Herschel
Sir William Herschel (1738–1822) was a prominent musician and composer in the 18th century England. He worked as a concert director in several cities. In addition, he was a master of various instruments, and an active solo performer. Herschel composed numerous orchestral and solo works. His music, however, is hardly known today. Many of his compositions remained unpublished, among them the Twenty-Four Caprices for Solo Violin. These caprices are one of the earliest technical studies for the instrument, which must be brought to the intermediate violin students’ and violin teachers’ attentions. The purpose of this study is to create a practical edition of the Twenty-Four Caprices for Solo Violin, and to make it available for violinists by publishing them. The dissertation will look into the performance practice of Hershel’s caprices. Based on a thorough research of the violin methods, the edition will provide fingerings, bowings, and practicing suggestions which are useful for students who wish to improve violin technique. The author of this study strongly believes that these neglected technical studies are extremely beneficial works for violinists, and they deserve to be made public. digital.library.unt.edu/ark:/67531/metadc822781/
The Role of Spirituality in Ethnic Minority Patients with Copd
COPD is the third leading cause of death in the United States and is the sixth leading cause of death for low-to middle income countries (Downs & Appel, 2006; GOLD, 2011). COPD is a largely preventable disease due to the lifestyle factors that heavily contribute to disease onset and severity. Although traditionally COPD research has focused on health outcomes related to risk factors, compliance, comorbid psychological and physical conditions, and treatment interventions, a growing body of research suggests religious and spiritual factors may play an equally important role in health outcomes for several medical conditions, including pulmonary disease. However, studies of this kind have not specifically examined COPD nor have they examined the role of religious and spiritual beliefs in COPD management among ethnic minority patients. As such, the current study aimed to examine whether spiritual ethnic minority patients with COPD hold religious fatalistic attitudes and less active religious problem solving . A sample of 35 ethnic minority patients from the Louis. B. Stokes Cleveland VA Medical Center (LSCVAMC) Outpatient Pulmonary Clinic in Cleveland, OH. were recruited to participate in the study. Due to the acknowledgeable limitations of the present study, results are preliminary but convey associations between religious health fatalistic beliefs and religious problem solving approaches. Implications and areas of future study are discussed. digital.library.unt.edu/ark:/67531/metadc822782/
Václav Philomathes’ Musicorum Libri Quattuor (1512): Translation, Commentary, and Contextualization
The Czech-born music theorist, Václav Philomathes, wrote the Musicorum libri quattuor in 1512 while attending the University of Vienna. This didactic treatise became one of the most widely published theory treatise of its time with 26 copies of five editions remaining today and covers the topics of Gregorian chant practice, Solmization, Mensural Notation, Choir Practice and Conducting, and Four-voice Counterpoint. Of particular note, is the section on choir practice and conducting, of which there is no equivalent prior example extant today. This dissertation provides a Latin-English translation of Philomathes’s work, as well as produces a critical commentary and comparison of the five editions while positioning the editions within the context of the musico-theoretical background of early-to-mid-16th century scholarship in Central Europe. digital.library.unt.edu/ark:/67531/metadc822783/
Self-efficacy, Academic Engagement, and Student-teacher Relationships for Ninth-grade African American Male Students’ Algebra I Achievement: a Structural Equation Model
The purpose of the current study was to discern the effects of three latent constructs – self-efficacy, academic engagement, and student-teacher relationships on Algebra I achievement among ninth-grade African American male students. A nationally representative sample from the High School Longitudinal Study of 2009 (HSLS09) was used in the study. Study participants were 697 African American males enrolled in ninth grade in the fall of 2009 across the United States. Structural Equation Modeling (SEM) analytical procedures were performed to test the hypothesized relationships of Bandura’s social cognitive theory (SCT) theoretical assumptions. The results indicate that the three latent variables directly or indirectly were related to Algebra I achievement among ninth grade African American male students. Moreover, the results revealed that self-efficacy and student-teacher relationships constructs had direct significant impact on Algebra I academic performance; nonetheless, the relationships were not strong. These two latent variables had small effect sizes of 5% and 1%, respectively. Combined, self-efficacy, academic engagement, and student-teacher relationships explained only 8% of the variance in the Algebra I achievement among African American males across the United States (R2=.08). The magnitude effect of these factors on Algebra I achievement was minimal. Overall, these findings suggest that the self-efficacy and student-teacher relationships latent variables had a negligible effect as predictors of Algebra I academic success among ninth grade African American male students. A summary of the results are presented and future research is recommended. digital.library.unt.edu/ark:/67531/metadc822785/
Expertise Revisited: Reflecting on the Intersection of Science and Democracy in the Case of Fracking
This dissertation aims to explain the conditions under which expertise can undermine democratic decision making. I argue that the root of the conflict between expertise and democracy lies in what I call insufficiently “representative” expertise – that is forms of scientific research that are not relevant to the policy questions at hand and that fail to make visible their hidden values dimensions. I claim that the scholarly literature on the problem of expertise fails to recognize and address the issue correctly, because it does not open the black box of scientific methodologies. I maintain that only by making sense of the methodological choices of experts in the context of policy making can we determine the relevance of research and reveal the hidden socio-political values and consequences. Using the case of natural gas fracking, I demonstrate how expert contributions – even though epistemically sound – can muddle democratic policy processes. I present four case studies from controversies about fracking to show how to contextualize scientific methodologies in the pertinent political process. I argue that the common problem across all case studies is the failure of expertise to sufficiently represent stakeholders’ problems and concerns. In this context, “representation” has three criteria: (1) the operational research questions on which the qualified experts work are relevant to stakeholders’ problems and concerns; (2) the non-epistemic values and consequences of epistemic choices of experts are compatible with social and political values and priorities; and (3) hidden values attached to facts are fully transparent and openly debated. In the conclusion, I propose a normative version of this representation theory that can be used to evaluate the appropriateness of expertise for democratic policy making. Instead of the value-free science ideal, I propose a new ideal to legitimately allow non-epistemic values in scientific reasoning without compromising the soundness of research. digital.library.unt.edu/ark:/67531/metadc822786/
High School Contemporary a Cappella: a Descriptive Phenomenology
This study examines the phenomenon of contemporary a cappella music making found in high school settings as curricular and extra-curricular offerings. Past music and music education literature has focused exclusively on contemporary a cappella at the collegiate level. Through application of a descriptive phenomenological method and incorporation an educational-sociological lens, this study advances an understanding of the educational benefit and social value of membership in contemporary a cappella at the high school level. Six recent members from three regions of the United States provided data through individual open-form interviews in which questions were derived from the participants’ own speech. I incorporated phenomenological reductions and processes to negate researcher bias during data collection, analysis, and the formation of a general structure and constituent meanings of membership in high school contemporary a cappella. Participants utilized traditional music skills, individual talents, conceptions of popular culture and music, and in-group socialization to facilitate music making and reify membership. Expressing the value of group membership, individuals acted to benefit the group by cultivating social bonds, developing and fostering personal/shared connections to songs, identifying and purposing individual talents and skills, and gaining an understanding of each members’ unique contribution to membership. Discussion includes implications for music education and suggestions for future research. digital.library.unt.edu/ark:/67531/metadc822787/
Design, Synthesis, and Characterization of Aqueous Polymeric Hybrid Composites and Nanomaterials of Platinum(ii) and Gold(i) Phosphorescent Complexes for Sensing and Biomedical Applications
The two major topics studied in this dissertation are the gold(I) pyrazolate trimer {[Au(3-R,5-R’)Pz]3} complexes in aqueous chitosan polymer and phosphorescent polymeric nanoparticles based on platinum(II) based complex. The first topic is the synthesis, characterization and optical sensing application of gold(I) pyrazolate trimer complexes within aqueous chitosan polymer. A gold(I) pyrazolate trimer complex, {[Au(3-CH3,5-COOH)Pz]3}, shows high sensitivity and selectivity for silver ions in aqueous media, is discussed for optical sensing and solution-processed organic light emitting diodes (OLEDs) applications. Gold(I) pyrazolate trimer complexes are bright red emissive in polymeric solution and their emission color changes with respect to heavy metal ions, pH and dissolved carbon dioxide. These photophysical properties are very useful for designing the optical sensors. The phosphorescent polymeric nanoparticles are prepared with Pt-POP complex and polyacrylonitrile polymer. These particles show excellent photophysical properties and stable up to >3 years at room temperature. Such nanomaterials have potential applications in biomedical and polymeric OLEDs. The phosphorescent hybrid composites are also prepared with Pt-POP and biocompatible polymers, such as chitosan, poly-l-lysine, BSA, pnipam, and pdadmac. Photoluminescent enhancement of Pt-POP with such polymers is also involved in this study. These hybrid composites are promising materials for biomedical applications such as protein labeling and bioimaging. digital.library.unt.edu/ark:/67531/metadc822788/
Mineola
Mineola is a poetic, observational, immersive documentary centered in the town of Mineola, Texas. The film provides an intimate, first person perspective of different locations in the town as well as underlying subversive beliefs and traditions. The film’s authoritative perspective guides the viewer not only in a direction of observation but personal connection to nostalgia of small communities. digital.library.unt.edu/ark:/67531/metadc822789/
Longitudinal Prevalence of Disordered Eating and Weight Control Behaviors in Female Collegiate Athletes
Female collegiate athletes have been established as a high-risk group for the development of eating disorders due to the high prevalence rates of clinical and subclinical eating disorders, which have ranged from 1.9% to 16.6% and 4.0% to 26.1%, respectively. Collegiate athletes appear to meet criteria for ED-NOS more often than anorexia or bulimia nervosa, and frequently engage in pathogenic weight control behaviors (e.g., dieting, excessive exercise). To date, only a few studies have examined the long-term stability of eating disorders in collegiate female athletes. The current study investigated the prevalence of eating disorders (i.e., eating disordered, symptomatic, and asymptomatic) and pathogenic weight control behaviors (e.g, binging, vomiting, laxative use) in 325 NCAA-DI female collegiate gymnasts and swimmers/divers across two time points – the beginning of their competitive seasons (Time 1) and during the final two weeks of their competitive seasons (Time 2). By Time 2, 90% of the athletes classified as eating disordered at Time 1 (n = 20) maintained clinical or subclinical eating disturbances. Of the 83 athletes originally symptomatic, 37.3% remained so and 10.8% became eating disordered. Significantly more athletes became satisfied with their bodies over the course of the season than became dissatisfied. The athletes reported using exercise and dieting/fasting as the most frequent forms of weight control behaviors, each of which were used less frequently at Time 2 than at Time 1. The results support overall stability of eating disorder behaviors and classification over the course of a competitive season. Limitations and implications are discussed. digital.library.unt.edu/ark:/67531/metadc822790/
Effects of Child Development Associate Credential System 20 on Candidate Success Rates
The purpose of this research was to identify the impact of process changes that have been made to the Child Development Associate (CDA) credential, which is a beginning early childhood teacher credential that focuses on competency based standards widely seen as necessary for early childhood teachers to possess. The process in which early childhood teachers receive their credential changed in 2013 with the implementation of CDA credential 2.0. Changes included taking a computerized exam and the implementation of a professional development specialist conducting an on-site classroom observation. In order to determine the impact that CDA 2.0 had on teacher credentialing success rates, a mixed-method sequential design was employed. First, existing data sets of success rates from a national scholarship program were reviewed. Following, interviews with CDA credential seekers were conducted. Findings revealed that while candidate success rates increased for those receiving CDA credentials under the 2.0 system, the actual number of candidates receiving scholarships to pursue the CDA credential through the national scholarship program decreased. Qualitative analysis of the semi-structured interviews indicated that three areas that impacted CDA 2.0 candidate success rates were the professional education programs and instructors, the CDA Exam, and Professional Development Specialists. This is the first research study to examine the CDA credential process. The findings demonstrate that the 2.0 system provides candidates with necessary supports to be successful. A significant question arising out of the data is how a determination is made to issue a credential. Before QRIS and public policy initiatives employ more efforts to professionalize the field of early childhood – primarily through the CDA credential – the process by which one obtains a credential should be more thoroughly examined. digital.library.unt.edu/ark:/67531/metadc822791/
The Role of Crystallographic Texture in Achieving Low Friction Zinc Oxide Nanolaminate Films
Metal oxide nanolaminate films are potential high temperature solid lubricants due to their ability to exhibit significant plasticity when grain size is reduced to the nanometer scale, and defective growth structure is achieved by condensation of oxygen vacancies to form intrinsic stacking faults. This is in contrast to conventional microcrystalline and single crystal oxides that exhibit brittle fracture during loading in a sliding contact. This study emphasizes the additional effect of growth orientation, in particular crystallographic texture, on determining the sliding friction behavior in nanocolumnar grain zinc oxide films grown by atomic layer deposition. It was determined that zinc oxide low (0002) versus higher (101 ̅3) surface energy crystallographic planes influenced the sliding friction coefficient. Texturing of the (0002) grains resulted in a decreased adhesive component of friction thereby lowering the sliding friction coefficient to ~0.25, while the friction coefficient doubled to ~0.5 with increasing contribution of surface (101 ̅3) grains. In addition, the variation of the x-ray grazing incident angle from 0.5° to 5° was studied to better understand the surface grain orientation as a function of ZnO layer thickness in one versus four bilayer nanolaminates where the under layer (seed layer) was load-bearing Zn(Ti,Zr)O3. digital.library.unt.edu/ark:/67531/metadc822792/
Does Instructional Delivery Method in an Elective Business Class Impact Student Achievement with Respect to Gender, Race and Socio-economic Status in a Selected Texas Public School District?
The problem that guided this study was a socio-constructivist view of education via online learning. Based in the extant literature, a deficiency existed that directly correlated online learning closing the academic achievement gap between student populations. In other words, schools invested in technology; however, few empirical data sets existed that established a connection between technology integration and the academic achievement of different student groups. The purpose of this pooled regression analysis study was to determine whether the method of class instruction effected academic achievement gaps between three subpopulations based on gender, race, and SES. Specifically, this study examined whether gender, race, and SES could predict semester grades within and across traditional, blended, and online course instructional methods. The dependent variable for this study was student success in the form of an end-of-unit test grade designed to evaluate student understanding of the curriculum. The independent variables included student gender, ethnicity, and SES. Quantitative data were collected through an analysis of Public Education Information Management System (PEIMS) data and student end-of-unit exam grades. The research suggests one combined interaction, [gender x race] in the traditional learning environment, is statistically significant while several independent interactions are significant. Those independent interactions are TAKS scores, gender, and Socio-economic status. According to the trends in this research, no significant differences exists in academic achievement between African American males and White males enrolled in traditional, blended or online classes. This non-significance is important. As suggested, when all other external factors, in this research, are held constant and the academic playing field is level, male students perform equally within the classroom, also, because no significant differences exists in academic achievement, the quality of instruction from well-trained, highly qualified educators can be an integral factor in closing the achievement gap between African American, low-SES male students. digital.library.unt.edu/ark:/67531/metadc822793/
Fundamental Studies of Copper Corrosion in Interconnect Fabrication Process and Spectroscopic Investigation of Low-k Structures
In the first part of this dissertation, copper bimetallic corrosion and its inhibition in cleaning processes involved in interconnect fabrication is explored. In microelectronics fabrication, post chemical mechanical polishing (CMP) cleaning is required to remove organic contaminants and particles left on copper interconnects after the CMP process. Use of cleaning solutions, however, causes serious reliability issues due to corrosion and recession of the interconnects. In this study, different azole compounds are explored and pyrazole is found out to be a potentially superior Cu corrosion inhibitor, compared to the most widely used benzotriazole (BTA), for tetramethyl ammonium hydroxide (TMAH)-based post CMP cleaning solutions at pH 14. Micropattern corrosion screening results and electrochemical impedance spectroscopy (EIS) revealed that 1 mM Pyrazole in 8 wt% TMAH solution inhibits Cu corrosion more effectively than 10 mM benzotriazole (BTA) under same conditions. Moreover, water contact angle measurement results also showed that Pyrazole-treated Cu surfaces are relatively hydrophilic compared to those treated with BTA/TMAH. X-ray photoelectron spectroscopy (XPS) analysis supports Cu-Pyrazole complex formation on the Cu surface. Overall Cu corrosion rate in TMAH-based highly alkaline post CMP cleaning solution is shown to be considerably reduced to less than 1Å/min by addition of 1 mM Pyrazole. In the second part, a novel technique built in-house called multiple internal Reflection Infrared Spectroscopy (MIR-IR) was explored as a characterization tool for characterization of different low-k structures.In leading edge integrated circuit manufacturing, reduction of RC time delay by incorporation of porous ultra low-k interlayer dielectrics into Cu interconnect nanostructure continues to pose major integration challenges. The main challenge is that porous structure renders interlayer dielectrics mechanically weak, chemically unstable and more susceptible to the RIE plasma etching damages. Besides the challenge of handling weak porous ultra low-k materials, a lack of sensitive metrology to guide systematic development of plasma etching, restoration and cleaning processes is the major stumbling block. We explored Multiple Internal Reflection Infrared Spectroscopy and associated IR techniques as a sensitive (sub-5 nm) characterization tool to investigate chemical bonding modification across fluorocarbon etch residues and low-k dielectric interface after plasma etching, ashing, UV curing and post-etch cleaning. The new insights on chemical bonding transformation mapping can effectively guide the development of clean-friendly plasma etch for creating ultra low-k dielectric nanostructures with minimal dielectric damages. digital.library.unt.edu/ark:/67531/metadc822794/
The Impact of Computational Methods on Transition Metal-containing Species
Quantum chemistry methodologies can be used to address a wide variety of chemical problems. Key to the success of quantum chemistry methodologies, however, is the selection of suitable methodologies for specific problems of interest, which often requires significant assessment. To gauge a number of methodologies, the utility of density functionals (BLYP, B97D, TPSS, M06L, PBE0, B3LYP, M06, and TPSSh) in predicting reaction energetics was examined for model studies of C-O bond activation of methoxyethane and methanol. These species provide excellent representative examples of lignin degradation via C-O bond cleavage. PBE0, which performed better than other considered DFT functionals, was used to investigate late 3d (Fe, Co, and Ni), 4d (Ru, Rh, and Pd), and 5d (Re, Os, and Ir) transition metal atom mediated Cβ -O bond activation of the β–O–4 linkage of lignin. Additionally, the impact of the choice of DFT functionals, basis sets, implicit solvation models, and layered quantum chemical methods (i.e., ONIOM, Our Own N-layered Integrated molecular Orbital and molecular Mechanics) was investigated for the prediction of pKa for a set of Ni-group metal hydrides (M = Ni, Pd, and Pt) in acetonitrile. These investigations have provided insight about the utility of a number of theoretical methods in the computation of thermodynamic properties of transition metal hydrides in solution. As single reference wavefunction methods commonly perform poorly in describing molecular systems that involve bond-breaking and forming or electronic near-degeneracies and are typically best described with computationally costly multireference wavefunction-based methods, it is imperative to a priori analyze the multireference character for molecular systems so that the proper methodology choice is applied. In this work, diagnostic criteria for assessing the multireference character of 4d transition metal-containing molecules was investigated. Four diagnostics were considered in this work, including the weight of the leading configuration of the CASSCF wavefunction, C02; T1, the Frobenius norm of the coupled cluster amplitude vector related to single excitations and D1, the matrix norm of the coupled cluster amplitude vector arising from coupled cluster calculations; and the percent total atomization energy, %TAE. This work demonstrated the need to have different diagnostic criteria for 4d molecules than for main group molecules. digital.library.unt.edu/ark:/67531/metadc822795/
Shame Due to Heterosexism, Self-esteem and Perceived Stress: Correlates of Psychological Quality of Life in a Lesbian, Gay and Bisexual Sample
Sexual minorities experience higher levels of stress than heterosexuals, which in turn affects coping and psychological quality of life (PQOL). Although many sexual minorities remain mentally healthy, a higher prevalence of mental disorders among members of the lesbian, gay and bisexual (LGB) communities exists; thus, LGB PQOL becomes an important area to examine. Several key factors are related to PQOL: shame due to heterosexism, self-esteem and perceived stress. Using minority stress model, I hypothesized that shame due to heterosexism and perceived stress are negatively correlated with PQOL, while self-esteem is positively correlated with PQOL. I hypothesized that collectively shame due to heterosexism, self-esteem and perceived stress account for a significant proportion of the variance in PQOL, that self-esteem moderates the relationship between perceived stress and PQOL and that age moderates the relationship between shame due to heterosexism and PQOL. I calculated Pearson product-moment correlation coefficient and found shame due to heterosexism was negatively correlated with PQOL (r(146) = -.21, p = .009), perceived stress was negatively correlated with PQOL (r (146) = -.69, p < .001) and self-esteem was positively correlated with PQOL (r(146) = .72, p < .001). I conducted a regression analysis and found our model accounted for 59% of the variance in PQOL (adj. R2 = .59, F(3, 144) = 68.88, p < .001). Self-esteem did moderate the relationship between perceived stress and PQOL (p = .029), but age did not moderate the relationship between shame due to heterosexism and PQOL. Results suggest perceived stress and self-esteem play key roles in sexual minorities’ PQOL. Implications are discussed. digital.library.unt.edu/ark:/67531/metadc822796/
Role of Gpr17 in Thrombocyte Aggregation in Adult Zebrafish
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GPR17, a uracil nucleotide cysteinyl leukotriene receptor, belongs to the GPCR (G protein coupled receptor) family. It has been shown recently that inhibiting this protein in the nervous system in mice can lead to blockage of oligodendrocyte maturation, which supports myelin repair. Interestingly, our laboratory found GPR17 in thrombocytes. However, we do not know whether it has any function in thrombocyte aggregation or the nature of the ligand. In this paper, we studied the role of GPR17 in hemostasis, which is a fundamental defense mechanism in the event of injury. Using zebrafish as a model system, our laboratory has studied specifically thrombocytes, which play a significant role in hemostasis. The major reasons to use zebrafish as a model system are that their thrombocytes are functionally equivalent to human platelets, the adult fish are amenable to knockdown experiments, and they are readily available in the market. This study was performed by using a piggy back knockdown method where we used a chemical hybrid of control morpholino and an antisense oligonucleotide sequence leads to the degradation the mRNA for GPR17. After knockdown GPR17 in thrombocytes, the percent difference of the thrombocytes aggregation between the control and knockdown blood samples was measured by flow cytometry. We used various thrombocyte agonists to study differences in aggregation between the control and knockdown blood samples. The study showed that knockdown of GPR17 resulted in no significant differences in percent thrombocyte aggregation between control and agonist treated samples except for a slight increase in collagen-treated samples. Thus, it appears that GPR17 has no significant role in hemostasis. digital.library.unt.edu/ark:/67531/metadc822797/
On City Identity and Its Moral Dimensions
The majority of people on Earth now live in cities, and estimates hold that 60 percent of the world’s cities have yet to be built. Now is the time for philosophers to develop a philosophy of the city to address the forthcoming issues that urbanization will bring. In this dissertation, I respond to this need for a philosophy of the city by developing a theory of city identity, developing some of the theory’s normative implications, illustrating the theory with a case study, and outlining the nature and future of philosophy of the city more generally. Indeed, this dissertation is only a part of my larger project of founding and institutionalizing this new field of both academic and socially-engaged philosophical activity. Throughout the history of the discipline, other areas such a personal identity have received numerous considerations, along with the concept of identity as an abstraction. For example, there is a bounty of research addressing problems pertaining to how objects and people retain an identity over time and claims about identity in general. While one could argue that cities are not any different than any other object, such an account fails to consider that a city’s dynamic nature makes it dissimilar to other things. To illustrate this point, I develop a position called dynamic composition as identity theory that provides a framework for understanding the identity of a city, exhibiting that views within analytic metaphysics are too narrow to apply to all cases. After establishing a concept of city identity, I use an applied mereology to develop a model of city identity that shows how the parts of a city fit together to form a complete city. This model introduces the normative dimension of my project by providing a way to identify how incongruence between a city’s parts can cause problems for residents’ wellbeing. To understand the moral dimensions of infrastructure, I argue that moral theory alone is ill prepared to adequately demonstrate its full range of effects. Yet, instead of developing another moral theory, we can supplement existing moral theories with the concepts of sustainability and resilience thinking to account for the elements that traditional moral systems neglect. I support this view with a detailed account of transportation infrastructure. Namely, I show that current frameworks for assessing transportation infrastructure are inadequate, and employ the method of complex moral assessment developed earlier to make such assessments. Lastly, I show how the research in this dissertation counts as intra-disciplinary research, a new kind of method for philosophical research. digital.library.unt.edu/ark:/67531/metadc822798/
Guidelines for Greening (Renovation) of Existing Homes
This Thesis is aimed at evaluating the options of renovation for an existing residential building to make it more energy efficient. The various aspects in the basic structures of residential homes are discussed in order to help the user identify the areas of the house for which renovation is required to improve the energy efficiency of the building. These aspects include doors, roof and wall in addition to various systems of electrical wiring, mechanical systems of ventilation, heating and cooling and plumbing systems for the efficient flow of water throughout the house. The renovation options have been described in detail to provide as many possibilities to the user as possible. The building taken for renovation is a 1953 suburban home which has been awarded the honor of being the first building to be labeled as Zero Energy Home in its vicinity. This has made the home so efficient that its expenditure of energy has become equivalent to its energy generation, therefore, cancelling each other out and creating an estimate of zero energy. digital.library.unt.edu/ark:/67531/metadc822735/
Characterizing the Molecular Changes of Austrofundulus Limnaeus As It Develops Towards and Enters Diapause Ii
Austrofundulus limnaeus is a species of annual killifish which inhabits ephemeral ponds in South America. The species is able to survive seasonally desiccating ponds due to their ability to produce robust embryos. The embryos of this species are capable of entering a developmental arrest, termed diapause II, which precedes the onset of drought. While in this arrested state embryos exhibit the greatest tolerance to anoxia of any characterized vertebrate at 25ºC. Furthermore, when raised at 30ºC, embryos escape the entrance to diapause II and go on to develop directly. Currently, little is known about the molecular mechanisms which induce and maintain this developmentally arrested state. In this study I have developed methods to analyze changes in histone modifications in the context of diapause II. Histone modifications were chosen due to their extreme conservation and well characterized role as modulators of gene expression in other systems. Results utilizing adapted immunobased assays show significant changes in the global amount of H3S10P, H3K27me and H3K4me, as the embryos progress from early embryogenesis through the exit of diapause. Additionally, it is revealed that there exists a degree of phenotypic plasticity with regards to the entrance into diapause II which is modulated by the environment (severe hypoxia 0.1% O2). This work builds a foundation for future histone modification studies and contributes the development of several tools to the field. This study contributes to a greater molecular understanding of the cue(s) which influence the remarkable phenomenon of obligate developmental arrest in a vertebrate embryo. digital.library.unt.edu/ark:/67531/metadc822736/
A Teaching Guide for Debussy and Ravel: Technical and Stylistic Applications for Korean Piano Teachers
Most Korean students study very little French music during their pre-college years. A survey of ten Korean piano professors as well as an investigation into the annual set repertoire from universities, music high schools, middle schools and national competitions in Korea show that French repertoire appears very seldom on the list of required repertoire. Therefore, it is easy for Korean students to neglect French piano music. By the time students reach undergraduate or graduate school and are required to play the music of Debussy and Ravel for the first time, they find themselves at a serious disadvantage. The purpose of this paper is to provide a pedagogical guide for Korean teachers who wish to offer their beginning, middle school and high school students a good foundation in the style of French piano music. This syllabus will introduce a series of French piano pieces, from Couperin and Rameau as well as Chaminade and Fauré to the easier pieces of Debussy and Ravel, which will lead to the ultimate goal of interpreting aspects of French tone, style, technique, and cultural context involved in the eventual successful performance of the more advanced pieces of Debussy and Ravel, which are the bedrock of French piano music. One of the most significant advantages of this syllabus is that it does not skip any steps in the repertoire. digital.library.unt.edu/ark:/67531/metadc822737/
Self-assembly Polymeric Nanoparticles Composed of Polymers Crosslinked with Transition Metals for Use in Drug Delivery
A major drawback of chemotherapy is the lack of selectively leading to damage in healthy tissue, which results in severe acute side effects to cancer patients. The use of nanoparticles as a drug delivery system has emerged as novel strategy to overcome the barriers of immunogenic response, controlled release of therapeutic, and targeting the toxicity only to cancerous cells. In this study, polymeric nanoparticles composed of transition metals and particles derived from natural biopolymers have been generated via self-assembly. For example, nanoparticles composed of cobalt crosslinked with albumin (Co-alb NPs) via Co-amine coordination chemistry of lysine residue were syntheisized in various sizes. The method to generate Co-alb NPs involves no thermal heat, organic solvent or any surfactants, which is ideal for the production of large amounts in a timely manner. The Co-alb NPs displayed exceptional stability under physiological conditions (pH 7.4) for several days with minor changes in size; however degradation could be triggered by reductant (reduced glutathione (GSH), 10 mM) with complete disappearance of particles in less than 2 hour. Numerous therapeutics that are highly effective toward cancer cells have been developed; however, many cannot be administered to patients due to poor solubility in water and pH dependent properties. We have successfully encapsulated 7-ethyl-10-hydroxycampothecin (SN-38) into Co-alb NPs with encapsulation efficiency as high as 94% and loading capacities greater than 30%. We employed an emulsion-solvent evaporation method to incorporate SN-38 into Co-alb (SN38 Co-Alb NPs). Release of the drug from SN38 Co-Alb NPs was determined for particles incubated in PBS or PBS-GSH. SN38 Co-Alb NPs were exceptionally stable under physiological condition (PBS pH 7.4), but exhibited sustained release of SN-38 over time in the presence of GSH. Uptake and toxicity of the particles were also investigated in a gastric carcinoma cell line (SNU-5) where high degrees of macropinocytic uptake were observed. The particles displayed significant toxicity making them a prime candidate for further testing in animal models. digital.library.unt.edu/ark:/67531/metadc822738/
Indigenous Knowledge on the Marshall Islands: a Case for Recognition Justice
Recent decades have marked growing academic and scientific attention to the role of indigenous knowledge in climate change adaptation, mitigation, and detection strategies. However, how indigenous knowledge is incorporated is a point of contention between self-identifying indigenous groups and existing institutions which combat climate change. In this thesis, I argue that the full inclusion of indigenous knowledge is deterred by certain aspects of modernity. In order to overcome the problems of modernity, I argue that a recognition theory of justice is needed as it regards to indigenous knowledge. Recognition justice calls for indigenous groups to retain meaningful control over how and when their indigenous knowledge is shared. To supplement this, I use the Marshall Islands as a case study. The Marshall Islands afford a nice particular case because of their longstanding colonial relationship with the United States and the impending danger they face of rising sea levels. Despite this danger, the Republic of the Marshall Islands calls for increased recognition as leaders in addressing climate change. digital.library.unt.edu/ark:/67531/metadc822739/
No Quarter: the Story of the New Orleans Greys
The purpose of this thesis document is to explain the process of making the documentary film, No Quarter: The Story of the New Orleans Greys. The document is organized by having the prospectus and the film proposal at the beginning, with the body describing how the film was made based on the prospectus. The purpose of the film is to tell the history of a unit of volunteers in the Texas Revolution, the New Orleans Greys. The document describes the methods used to make the film and how it will be distributed to the intended audience. As the thesis explains, the film changed slightly from the prospectus, however the resulting film was successful in telling the history of the little-known New Orleans Greys. digital.library.unt.edu/ark:/67531/metadc822740/
Retention: Course Completion Rates in Online Distance Learning
Online courses in higher education have a reputation for having a lower course completion or retention rate than face-to-face courses. Much of this reputation is based upon anecdotal evidence, is outdated, or is on a small scale, such as a comparison of individual courses or programs of instruction. A causal-comparative analysis was conducted among 11 large, high research public universities. The universities were compared to each other to determine if differences existed between online and face-to-face course completion; undergraduate and graduation online course completion was analyzed for differences as well. The findings suggested the magnitude of the differences between online and face-to-face completions rates was small or negligible. The area which showed a higher magnitude of difference was in the comparison between undergraduate and graduate online course completion; the practical significance could be worth considering for educational purposes. digital.library.unt.edu/ark:/67531/metadc822741/
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