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 Collection: UNT Theses and Dissertations
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/
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/
Addressing Multicultural Issues in the Counselor Education Classroom: a Phenomenological Analysis
Multicultural education in counselor education is a popular topic among counselor educators and scholars. To date, scholars have focused on understanding the experiences of counselor educators who teach dedicated multicultural courses. However, less attention has been given to other counselor educators who are required by ethical and training standards to address multicultural issues across the curriculum. The purpose of this study was to understand counselor educators’ experiences addressing multicultural issues in courses that do not have a specific multicultural or diversity focus. I used phenomenological methodology to explore the experiences of counselor educators who hold doctoral degrees in counseling or a related field, have taken a multicultural/diversity course in their graduate training, are full-time clinical or tenure-line faculty members in CACREP-accredited programs, and have never taught courses dedicated to multicultural or diversity issues. Twelve participants (six men and six women), ranging in age ranged from 31 to 65, participated in the study. Ten participants identified as White, one African-American, and one Hispanic. The research team identified eight themes: (1) reasons for avoidance, (2) constraints, (3) qualities and practices, (4) educator as a factor in student development, (5) infusion, (6) personal background, (7) awareness of biases and assumptions, and (8) counselor educator responsibility/gatekeeping. Findings from this study will add to the literature regarding infusion of multicultural issues across the curriculum. Additionally, the implications offered will serve as a resource for counselor educators as they experience unique personal and professional challenges when addressing multicultural issues in classrooms beyond the main multicultural or diversity course offered in counseling programs. Implications for this study may lead to development of more focused guidelines on how to increase the increase the comfort of counselor educators as they facilitate multicultural discussions and assist counselors-in-training in working toward cultural competence. digital.library.unt.edu/ark:/67531/metadc822760/
Anger, Forgiveness and Mindfulness: Correlates of Perceived Stress in an Lgb Sample
A sexual minority is someone who identifies as lesbian, gay or bisexual (LGB). According to the Minority Stress Model (Meyer, 2003), sexual minorities encounter significant levels of stress due to their minority group status, thus they are more likely to experience perceived stress. Our cross-sectional, correlational study aimed to explore the relationships between forgiveness, mindfulness and anger and how they are related to perceived stress in a convenience sample of ethnically diverse LGB adults. We hypothesized that: 1) anger is positively associated with perceived stress; 2) forgiveness is negatively associated with perceived stress; 3) mindfulness is negatively associated with perceived stress; and 4) anger, forgiveness and mindfulness account for a significant proportion of the variance in perceived stress. 5) The relationship between anger and perceived stress is moderated by forgiveness. 6) The relationship between anger and perceived stress is moderated by mindfulness. Among LGB adults, the extant literature does not address these four variables in conjunction and the relationships between anger, forgiveness, mindfulness and stress has yet to be explored. Various statistical analyses were conducted, including a hierarchical linear regression to test our model. We found that our overall model accounted for 36% of the total variance in perceived stress (F(5, 142) = 17.31, p <.01) with anger (β = .31, t = 3.55, p = .001) and forgiveness (β = -.21, t = -2.56, p < .05) as the significant predictors. Contrary to prediction, forgiveness and mindfulness did not moderate the relationship between anger and perceived stress in our LGB sample. Limitations, strengths, future research and implications are discussed. digital.library.unt.edu/ark:/67531/metadc822763/
Anisotropic Nature of Radially Strained Metal Tubes
Metal pipes are sometimes swaged by a metal cone to enlarge them, which increases the strain in the material. The amount of strain is important because it affects the burst and collapse strength. Burst strength is the amount of internal pressure that a pipe can withstand before failure, while collapse strength is the amount of external pressure that a pipe can withstand before failure. If the burst or collapse strengths are exceeded, the pipe may fracture, causing critical failure. Such an event could cost the owners and their customers millions of dollars in clean up, repair, and lost time, in addition to the potential environmental damage. Therefore, a reliable way of estimating the burst and collapse strength of strained pipe is desired and valuable. The sponsor currently rates strained pipes using the properties of raw steel, because those properties are easily measured (for example, yield strength). In the past, the engineers assumed that the metal would be work-hardened when swaged, so that yield strength would increase. However, swaging introduces anisotropic strain, which may decrease the yield strength. This study measured the yield strength of strained material in the transverse and axial direction and compared them to raw material, to determine the amount of anisotropy. This information will be used to more accurately determine burst and collapse ratings for strained pipes. More accurate ratings mean safer products, which will minimize risk for the sponsor’s customers. Since the strained metal has a higher yield strength than the raw material, using the raw yield strength to calculate burst and collapse ratings is a conservative method. The metal has even higher yield strength after strain aging, which indicates that the stresses are relieved. Even with the 12% anisotropy in the strained and 9% anisotropy in the strain aged specimens, the raw yield strengths are lower and therefore more conservative. I recommend that the sponsor continue using the raw yield strength to calculate these ratings. I set out to characterize the anisotropic nature of swaged metal. As expected, the tensile tests showed a difference between the axial and transverse tensile strength. The correlation was 12% difference in yield strength in the axial and transverse directions for strained material and 9% in strained and aged material. This means that the strength of the metal in the hoop (transverse) direction is approximately 10% stronger than in the axial direction, because the metal was work hardened during the swaging process. Therefore, the metal is more likely to fail in axial tension than in burst or collapse. I presented the findings from the microstructure examination, standard tensile tests, and SEM data. All of this data supported the findings of the mini-tensile tests. This information will help engineers set burst and collapse ratings and allow material scientists to predict the anisotropic characteristics of swaged steel tubes. digital.library.unt.edu/ark:/67531/metadc822747/
Áskell Másson’s Solos for Snare Drum: Maximizing Musical Expression Through Varying Compositional Techniques and Experimentation in Timbre
This dissertation and accompanying lecture recital explores the musical elements present in Áskell Másson’s three solos for snare drum, PRÍM (1984), KÍM (2001) and B2B: Back to Basics (2010). Two of the primary challenges for the performer when playing solo literature on a non-pitch oriented instrument are identifying thematic structures and understanding how to interpret all innovative sound production techniques employed within the music. A thematic and compositional analysis, as well as an investigation into the experimentation of timbre found in Másson’s three pieces for solo snare drum will help to clarify the musical complexities that are present throughout. digital.library.unt.edu/ark:/67531/metadc822754/
Assessment of Hot and Cool Executive Functioning Following Trauma Using the Traditional Stroop Task, Emotional Stroop Task, and a Novel Implicit Association Test
Individuals who have experienced a traumatic event and develop Post-Traumatic Stress Disorder (PTSD) frequently show deficits in both primarily “cool” and “hot” cognitive executive functions (e.g., traditional & emotional Stroop tasks, respectively) that can be impacted by high affective salience. Given the dimensional nature of psychopathology, questions remain about individuals within the general population who have experienced trauma but do not meet full criteria for PTSD and yet may manifest problems in these areas, especially areas of hot and cool executive functioning (EF). Thus, the current project was designed to assess hot and cool EF in a relatively large sample of individuals from the general population who have experienced trauma and currently demonstrate sub-clinical levels of post-traumatic symptoms. The Stroop task, Emotional Stroop task, and a novel modified Implicit Association Test were utilized to assess EF across a spectrum of individuals with varying traumatic histories and level of post-traumatic symptoms. Results suggest that a greater frequency of trauma experiences was moderately associated with worse performance on both hot and cool executive functioning measures. Specifically, females within the sample evidenced a close relationship between traumatic experiences, post-trauma symptoms, and executive functioning. Clinical and theoretical implications are discussed. digital.library.unt.edu/ark:/67531/metadc822731/
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/
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/
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/
Comparative Analysis and Implementation of High Data Rate Wireless Sensor Network Simulation Frameworks
This thesis focuses on developing a high data rate wireless sensor network framework that could be integrated with hardware prototypes to monitor structural health of buildings. In order to better understand the wireless sensor network architecture and its consideration in structural health monitoring, a detailed literature review on wireless sensor networks has been carried out. Through research, it was found that there are numerous simulation software packages available for wireless sensor network simulation. One suitable software was selected for modelling the framework. Research showed that Matlab/Simulink was the most suitable environment, and as a result, a wireless sensor network framework was designed in Matlab/Simulink. Further, the thesis illustrates modeling of a simple accelerometer sensor, such as those used in wireless sensor networks in Matlab/Simulink using a mathematical description. Finally, the framework operation is demonstrated with 10 nodes, and data integrity is analyzed with cyclic redundancy check and transmission error rate calculations. digital.library.unt.edu/ark:/67531/metadc822834/
Comparing Three Effect Sizes for Latent Class Analysis
Traditional latent class analysis (LCA) considers entropy R2 as the only measure of effect size. However, entropy may not always be reliable, a low boundary is not agreed upon, and good separation is limited to values of greater than .80. As applications of LCA grow in popularity, it is imperative to use additional sources to quantify LCA classification accuracy. Greater classification accuracy helps to ensure that the profile of the latent classes reflect the profile of the true underlying subgroups. This Monte Carlo study compared the quantification of classification accuracy and confidence intervals of three effect sizes, entropy R2, I-index, and Cohen’s d. Study conditions included total sample size, number of dichotomous indicators, latent class membership probabilities (γ), conditional item-response probabilities (ρ), variance ratio, sample size ratio, and distribution types for a 2-class model. Overall, entropy R2 and I-index showed the best accuracy and standard error, along with the smallest confidence interval widths. Results showed that I-index only performed well for a few cases. digital.library.unt.edu/ark:/67531/metadc822835/
Computational Modeling of Small Molecules
Computational chemistry lies at the intersection of chemistry, physics, mathematics, and computer science, and can be used to explain the behavior of atoms and molecules, as well as to augment experiment. In this work, computational chemistry methods are used to predict structural and energetic properties of small molecules, i.e. molecules with less than 60 atoms. Different aspects of computational chemistry are examined in this work. The importance of examining the converged orbitals obtained in an electronic structure calculation is explained. The ability to more completely describe the orbital space through the extrapolation of energies obtained at increasing quality of basis set is investigated with the use of the Sapporo-nZP-2012 family of basis set. The correlation consistent Composite Approach (ccCA) is utilized to compute the enthalpies of formation of a set of molecules and the accuracy is compared with the target method, CCSD(T,FC1)/aug-cc-pCV∞Z-DK. Both methodologies are able to produce computed enthalpies of formation that are typically within 1 kcal mol-1 of reliable experiment. This demonstrates that ccCA can be used instead of much more computationally intensive methods (in terms of memory, processors, and time required for a calculation) with the expectation of similar accuracy yet at a reduced computational cost. The enthalpies of formation for systems containing s-block elements have been computed using the multireference variant of ccCA (MR-ccCA), which is designed specifically for systems that require an explicit treatment of nondynamical correlation. Density functional theory (DFT) has been used for the prediction of the structural properties of a set of lanthanide trihalide molecules as well as the reaction energetics for the rearrangement of diphosphine ligands around a triosmium cluster. digital.library.unt.edu/ark:/67531/metadc822766/
Conquering the Natural Frontier: French Expansion to the Rhine River During the War of the First Coalition, 1792-1797
After conquering Belgium and the Rhineland in 1794, the French Army of the Sambre and Meuse faced severe logistical, disciplinary, and morale problems that signaled the erosion of its capabilities. The army’s degeneration resulted from a revolution in French foreign policy designed to conquer the natural frontiers, a policy often falsely portrayed as a diplomatic tradition of the French monarchy. In fact, the natural frontiers policy – expansion to the Rhine, the Pyrenees, and the Alps – emerged only after the start of the War of the First Coalition in 1792. Moreover, the pursuit of natural frontiers caused more controversy than previously understood. No less a figure than Lazare Carnot – the Organizer of Victory – viewed French expansion to the Rhine as impractical and likely to perpetuate war. While the war of conquest provided the French state with the resources to survive, it entailed numerous unforeseen consequences. Most notably, the Revolutionary armies became isolated from the nation and displayed more loyalty to their commanders than to the civilian authorities. In 1797, the Sambre and Meuse Army became a political tool of General Lazare Hoche, who sought control over the Rhineland by supporting the creation of a Cisrhenan Republic. Ultimately, troops from Hoche’s army removed Carnot from the French Directory in the coup d’état of 18 fructidor, a crucial benchmark in the militarization of French politics two years before Napoleon Bonaparte’s seizure of power. Accordingly, the conquest of the Rhine frontier contributed to the erosion of democratic governance in Revolutionary France. digital.library.unt.edu/ark:/67531/metadc822845/
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/
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/
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/
Decoding the Formation of a Retail Giant: the Evolving Geography of Costco’s Store Network
Although Costco operates over 580 warehouse stores throughout North America, their location strategy remains relatively unexamined in the economic geography literature. A cursory examination of Costco’s network makes it clear that the firm chooses to locate primarily in the suburbs of major cities, where income levels are somewhat higher than the national average. However, what is not clear is the extent to which other demographic and geographic factors adequately account for Costco’s store locations, and what strategy underlies the geography of the firm’s warehouse stores, especially in relation to its distribution network. This research studies Costco in order to decode the location strategies that have guided the company’s North American and international expansions. The investigation attempts to identify key elements of Costco’s multinational retail network, including this network’s evolution over time. This paper seeks to benefit both retail business and public policymakers by highlighting elements of Costco’s location strategy that have contributed to the firm’s success. digital.library.unt.edu/ark:/67531/metadc822836/
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/
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/
Detection of Ulcerative Colitis Severity and Enhancement of Informative Frame Filtering Using Texture Analysis in Colonoscopy Videos
There are several types of disorders that affect our colon’s ability to function properly such as colorectal cancer, ulcerative colitis, diverticulitis, irritable bowel syndrome and colonic polyps. Automatic detection of these diseases would inform the endoscopist of possible sub-optimal inspection during the colonoscopy procedure as well as save time during post-procedure evaluation. But existing systems only detects few of those disorders like colonic polyps. In this dissertation, we address the automatic detection of another important disorder called ulcerative colitis. We propose a novel texture feature extraction technique to detect the severity of ulcerative colitis in block, image, and video levels. We also enhance the current informative frame filtering methods by detecting water and bubble frames using our proposed technique. Our feature extraction algorithm based on accumulation of pixel value difference provides better accuracy at faster speed than the existing methods making it highly suitable for real-time systems. We also propose a hybrid approach in which our feature method is combined with existing feature method(s) to provide even better accuracy. We extend the block and image level detection method to video level severity score calculation and shot segmentation. Also, the proposed novel feature extraction method can detect water and bubble frames in colonoscopy videos with very high accuracy in significantly less processing time even when clustering is used to reduce the training size by 10 times. digital.library.unt.edu/ark:/67531/metadc822759/
Determinants of Effort and Associated Cardiovascular Response to a Behavioral Restraint Challenge
This study directly tested implications of motivation intensity theory on effort to restrain against a behavioral urge or impulse (i.e. restraint intensity). Two factors were manipulated—magnitude of an urge and the importance of successfully resisting it—with cardiovascular (CV) responses related to active coping measured. Male and female undergraduate students were presented with a mildly- or strongly evocative film clip with instructions to refrain from showing any facial response. Success was made more or less important through coordinated manipulations of outcome expectancy, ego-involvement, and performance assessment. As expected, systolic blood pressure responses assessed during the performance period were proportional to the evocativeness of the clip when importance was high, but low regardless of evocativeness when importance was low. These findings support a new conceptual analysis concerned with the determinants and CV correlates of restraint intensity. Implications of the study and associations with current self-regulatory literature are discussed. digital.library.unt.edu/ark:/67531/metadc822752/
Determining the Authenticity of the Concerto for Two Horns, Woo 19, Attributed to Ferdinand Ries
Ferdinand Ries is credited as the composer of the Concerto for Two Horns, WoO. 19 preserved in the Berlin State Library. Dated 1811, ostensibly Ries wrote it in the same year as his Horn Sonata, Op. 34, yet the writing for the horns in the Concerto is significantly more demanding. Furthermore, Ries added to the mystery by not claiming the Concerto in his personal catalog of works or mentioning it in any surviving correspondence. The purpose of this dissertation is to study the authorship of the Concerto for Two Horns and offer possible explanations for the variance in horn writing. Biographical information of Ries is given followed by a stylistic analysis of Ries’s known works. A stylistic analysis of the Concerto for Two Horns, WoO. 19 is offered, including a handwriting comparison between the Concerto for Two Horns and Ries’s Horn Sonata. Finally, possible explanations are proposed that rationalize the variance in horn writing between the Concerto for Two Horns, WoO. 19 and Ries’s other compositions that include the horn. digital.library.unt.edu/ark:/67531/metadc822748/
Determining the Emissivity of Roofing Samples: Asphalt, Ceramic and Coated Cedar
The goal is to perform heat measurements examine of selected roofing material samples. Those roofing materials are asphalt shingles, ceramics, and cedar. It’s important to understand the concept of heat transfer, which consists of conduction, convection, and radiation. Research work was reviewed on different infrared devices to see which one would be suitable for conducting my experiment. In this experiment, the main focus was on a specific property of radiation. That property is the emissivity, which is the amount of heat a material is able to radiate compared to a blackbody. An infrared measuring device, such as the infrared camera was used to determine the emissivity of each sample by using a measurement formula consisting of certain equations. These equations account for the emissivity, transmittance of heat through the atmosphere and temperatures of the samples, atmosphere and background. The experiment verifies how reasonable the data is compared to values in the emissivity table. A blackbody method such as electrical black tape was applied to help generate the correct data. With this data obtained, the emissivity was examined to understand what factors and parameters affect this property of the materials. This experiment was conducted using a suitable heat source to heat up the material samples to high temperature. The measurements were taken during the experiment and displayed by the IR camera. The IR images show the behavior of surface temperatures being distributed throughout the different materials. The main challenge was to determine the most accurate emissivity values for all material samples. The results obtained by the IR camera were displayed in figures and tables at different distances, which was between the heap lamp and materials. The materials exhibited different behaviors in temperature and emissivity at certain distances. The emissivity of each material varied with different temperatures. The results led to suggestions of certain materials that could be beneficial and disadvantageous in energy and cost savings during cold and hot seasons of the year. Also this led to some uncertainties in the data generated. Overall, this can support in exploring other ideas to increase energy and cost saving consistently during both season by using a material that can change its color and density based on a high or low temperature. digital.library.unt.edu/ark:/67531/metadc822838/
Direct Strength Method for Web Crippling of Cold-formed Steel C and Z Sections Subjected to Interior One Flange Loading and End One Flange Loading
The main objective of this research is to extend the “Direct strength method” for determining the web crippling strength of cold-formed steel C and Z sections subjected to End one flange loading and Interior one flange loading conditions. Direct strength method is applied for designing the columns and beams earlier. The existing specifications equation for calculating the web crippling strength of cold-formed steels designed by American Institute of Iron and Steel is very old method and it is based on the extensive experimental investigations conducted at different universities. Calculating the web crippling strength of cold-formed steels using direct strength method is a new technique. In the present research the web crippling strength of cold-formed steels were calculated using Direct Strength Method. The experimental data is collected from the tests that were conducted at different universities. The critical buckling strength of the members were calculated using Abaqus. Microsoft excel is used to generate the equations. The safety and resistance factors for the designed equations were calculated using “Load and resistance factor design” and “Allowable strength design” from North American Cold-Formed Steel Specification, 2012 edition book. digital.library.unt.edu/ark:/67531/metadc822839/
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/
An Educational Intervention to Promote Self-management and Professional Socialization in Graduate Nurse Anesthesia Students
Traditionally, nurse anesthesia educators have utilized prior academic achievement to predict student success. However, research has indicated that prior academic achievement offers an inadequate assessment of student success in graduate healthcare programs with extensive clinical residencies. The educational literature has identified many non-cognitive factors, such as self-efficacy and locus of control, that may provide a more holistic prediction model of student success. An experimental study with pretest-posttest design and stratified random assignment was conducted to evaluate the effectiveness of an educational intervention to promote self-management, professional socialization, and academic achievement among first semester graduate nurse anesthesia students. Participants (N = 66) were demographically similar to the national graduate nurse anesthesia student body, though Hispanics and younger students were a little over-represented in the sample (56% female, 75.8% White, 15.2% Hispanic, 6% Other, 59% ≤ 30-years-old, 67% ≤ 3 years of ICU). The results showed that most graduate anesthesia students had strong self-management and professional socialization characteristics on admission. The results did not support the effectiveness of this educational intervention. Thus, ceiling effect may have accounted in part for statistically non-significant results regarding self-efficacy (p = .190, ω2 = .03), locus of control (p = .137, ω2 = .04), professional socialization (p = .819, ω2 = .001), and academic achievement (p = .689, ω2 = .003). Future researchers may need to expand the scope of the intervention, use a more powerful and sensitive instrument, and utilize a larger sample. digital.library.unt.edu/ark:/67531/metadc822767/
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/
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/
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/
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/
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/
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/
Exploring the Dual-natured Impact of Digital Technology on Student-classroom Engagement in a Texas Public High School
The past decade has become rife with an eagerness to integrate new digital technology into teaching. While there have been decades of research done on the importance of curriculum and pedagogy on student engagement, findings of actual technology integration are scarce. Moreover, what does it take to engage students in classroom activities and lessons when technology is introduced? The purpose of this study was to explore how digital technology, when integrated into classroom teaching and activities, impacted the students-classroom engagement based on the interim-cognitive, meta-cognitive, motivational, and behavioral markers. This was explored in a Texas public high school across the four core classes (English, Math, Science, and Social Studies. Data was collected in the form of observational field notes, transcripts of recorded lessons, and Likert-scaled surveys. Thematic analysis was used in analyzing qualitative data, Pearson’s correlation of those components found by factor analysis verified three of the five themes identified from the thematic analysis with statistical significance. The findings suggest that mere use of technology does not have a profound impact on student engagement. Instead, technology tends to amplify the existing classroom culture and social norms agreed upon between the teacher and their students. Texas teachers and students are also redefining the meaning of curriculum to include technology as a result of the attempted integration. This research finds that students’ hands-on activities under teachers’ guidance with the use of technology excel when teachers are molding digital work. digital.library.unt.edu/ark:/67531/metadc822755/
Exploring the Effectiveness of Curriculum Provided Through Transmedia Books for Increasing Students’ Knowledge and Interest in Science
Transmedia books are new and emerging technologies which are beginning to be used in current classrooms. Transmedia books are a traditional printed book that uses multiple media though the use of Quick Response (QR) codes and augmented reality (AR) triggers to access web-based technology. Using the transmedia book Skills That Engage Me students in kindergarten through second grade engage in curriculum designed to introduce science skills and careers. Using the modified Draw-a-Scientist Test (mDAST), observations and interviews, researchers analyzed pre and post data to describe changes students have about science and scientists. Future study may include the development and validation of a new instrument, Draw a Science Student, and examining the mDAST checklist with the intention of updating the parameters of what is considered positive and negative in relationship with work a scientist conducts. digital.library.unt.edu/ark:/67531/metadc822809/
Foreign Sponsorship and the Development of Rebel Parties
This dissertation examines the emergence, survival, performance, and national impact of rebel parties following negotiated settlements. Building on a growing literature examining the environmental and organizational factors affecting insurgent-to-party transformations, this dissertation asks why some insurgent organizations thrive as political parties in post-conflict environments and others fail to make such a transformation. I propose that foreign actors play a pivotal role in the formation of what I call “protégé parties,” which are better equipped to make the transformation into political parties than other rebel groups. Further, different kinds of sponsors have varying effects on transformation. Empirical analysis supports these propositions, finding that protégé parties with authoritarian sponsorship are better equipped to develop than those backed by democracies or no one. digital.library.unt.edu/ark:/67531/metadc822815/
Form in Popular Song, 1990-2009
Through an examination of 402 songs that charted in the top 20 of the Billboard year-end charts between the years 1990 and 2009, this dissertation builds upon previous research in form of popular song by addressing the following questions: 1) How might formal sections be identified through melody, harmony, rhythm, instrumentation, and text? 2) How do these sections function and relate to one another and to the song as a whole? 3) How do these sections, and the resulting formal structures, relate to what has been described by previous theorists as normative? 4) What new norms and trends can be observed in popular song forms since 1990? Although many popular songs since 1990 do follow well-established forms, some songwriters and producers change and vary these forms. AAA strophic form, AABA form, Verse-Chorus form, Verse-Chorus with Prechorus and/or Postchorus sections, Verse-Chorus-Bridge form, “Other, with a Chorus” and “Other, without a Chorus” forms are addressed. An increasing number of the songs in each of the above listed forms are based on a repeating harmonic progression or no harmonic progression at all. In such songs, the traditional method of identifying sections and section-functions through harmonic analysis is less useful as an analytical tool, and other musical elements (melody, rhythm, instrumentation, and text) are as important, if not even more so, in determining the form of songs in the sample. digital.library.unt.edu/ark:/67531/metadc822808/
Fractional Calculus and Dynamic Approach to Complexity
Fractional calculus enables the possibility of using real number powers or complex number powers of the differentiation operator. The fundamental connection between fractional calculus and subordination processes is explored and affords a physical interpretation for a fractional trajectory, that being an average over an ensemble of stochastic trajectories. With an ensemble average perspective, the explanation of the behavior of fractional chaotic systems changes dramatically. Before now what has been interpreted as intrinsic friction is actually a form of non-Markovian dissipation that automatically arises from adopting the fractional calculus, is shown to be a manifestation of decorrelations between trajectories. Nonlinear Langevin equation describes the mean field of a finite size complex network at criticality. Critical phenomena and temporal complexity are two very important issues of modern nonlinear dynamics and the link between them found by the author can significantly improve the understanding behavior of dynamical systems at criticality. The subject of temporal complexity addresses the challenging and especially helpful in addressing fundamental physical science issues beyond the limits of reductionism. digital.library.unt.edu/ark:/67531/metadc822832/
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/
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/
Hâfez and Betinis: a Conductor’s Approach to Ancient Persian Poetry As Voiced by a Twenty-first Century, Western Composer
The choral music of Abbie Betinis is being widely performed and commissioned by prominent high school, university, and civic choruses. This study examines From Behind the Caravan: Songs of Hâfez, a five-movement work by Betinis for women’s chorus, vielle, oud, and Persian percussion. Four ghazals by Hâfez of Shiraz, a fourteenth century Sufi poet, are used as the text for Betinis’s Caravan. When considering a performance of this work, a conductor must understand proper treatment of the text, available translation options, Hâfez’s vast world of imagery, vocal demands inherent to the work, alternate instrumentations available and the benefits of each, how to approach improvisatory passages, how to engage heterophonic elements, and how to prepare a Western choir and audience with very little to no understanding of the philosophies of Sufism that heavily influence the work. This study addresses the body of practical knowledge gained after a year of examining, researching, teaching, and performing this work. digital.library.unt.edu/ark:/67531/metadc822732/
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/
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/
Identification and Characterization of an Arabidopsis Thaliana Mutant with Tolerance to N-lauroylethanolamime
N-Acylethanolamines (NAEs) are fatty acid derivatives in plants that negatively influence seedling growth. N-Lauroylethanolamine (NAE 12:0), one type of NAE, inhibits root length, increases radial swelling of root tips and reduces root hair numbers in a dose dependent manner in Arabidopis thaliana L. (ecotype Columbia). A forward genetics approach was employed by screening a population of T-DNA “activation-tagged” developed by the Salk Institute lines for NAE resistance to identify potential genes involved in NAE signaling events in Arabidopsis thaliana L. (ecotype Columbia). Seeds of the activation tagged lines were grown at 0, 25, 30, 50, 75 and 100 µM N-lauroylethanolamime (NAE 12:0). Ten plants which displayed NAE tolerance (NRA) seedling phenotypes, compared with wildtype (Columbia, Col-0) seedlings were identified. I focused on one mutant line, identified as NRA 25, where the tolerance to NAE 12:0 appears to be mediated by a single dominant, nuclear gene. Thermal asymmetric interlaced (TAIL) PCR identified the location of the T-DNA insert as 3.86 kbp upstream of the locus At1g68510. Quantitative PCR indicated that the transcript level corresponding to At1g68510 is upregulated approximately 20 fold in the mutant relative to wildtype. To determine whether the NAE tolerance in NRA 25 is associated with overexpression of At1g68510 I created overexpressing lines of At1g68510 with and without GFP fusions behind the 2X35S CaMV promoter. As predicted, results with overexpressing lines of At1g68510 also exhibited enhanced resistance to NAE when compared with the wildtype. Confocal images of the fusion proteins suggest that GFP-At1g68510 is concentrated in the nucleus and this was confirmed by counterstaining with 4', 6-Diamidino-2-phenylindol (DAPI). Futhermore, At1g68510 overexpressing lines and NRA 25 line also exhibited tolerance to abscisic acid (ABA) during seedling germination. The findings suggests that At1g68510 overexpression mediates seedling tolerance to both ABA and NAE, a mechanism independent of fatty acid amide hydrolase in which its overexpression leads to NAE resistance but hypersensitivity to ABA. The next steps are to identify the association of At1g68510 with specific genomic regions or interacting proteins that may be additional components of NAE signaling in plants. digital.library.unt.edu/ark:/67531/metadc822833/
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/
Impact of a Genetically Engineered Probiotic Therapy and Igf-1 Genomics in the Pahenu2 Mouse Model of Pku
Absence of functional phenylalanine hydroxylase results in phenylketonuria (PKU). Viable treatments remain few, expensive and secondary conditions such as osteopenia occur in most PKU patients. Objective 1: Given the recently described roles of gut microbes to aid host digestion, an orally administered genetically engineered probiotic as the delivery vehicle for enzyme replacement therapy was created. The engineered probiotic, pHENOMMenal, produced phenylalanine ammonia lyase with significant production of trans-cinnamate (phenylalanine cleavage product) in vitro and resulted in a reduction of 515 μM in blood phenylalanine when fed to PKU animals for 14 days (from 2307µM ± 264µM to 1792µM ± 261µM, n = 6, P < 0.05). The control probiotic produced no change in blood phenylalanine. Thus, pHENOMMenal treatment in PKU mice demonstrated engineered microbes could compensate for a metabolic deficiency of the host. Objective 2: Evaluate the PAHenu2 mouse model of PKU for a genetic discrepancy causing ocular enlargement and delayed development observed only after the PAHenu2 mutation was crossed to the C57BL/6J mouse. When compared to healthy littermates, ELISA indicated a consistent but insignificant decrease in plasma IGF-1 and an increase in ocular IGF-1 in PKU animals. SNP screening demonstrated a differential inheritance of IGF-1 alleles in healthy and PKU animals based on PAH allele inheritance. Ocular and developmental phenotypes in the PAHenu2 colony match those described in previous IGF-1 studies. Understanding the IGF-1 inheritance discrepancy will enable better osteopenia research using PAHenu2 mice and allow breeding of a healthier mouse colony for continued research. Collectively the results from this work describe a new therapeutic approach for treatment of PKU as well as a better understanding of the PAHenu2 mouse model to study this disease. digital.library.unt.edu/ark:/67531/metadc822730/
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/
Impact of Green Design and Technology on Building Environment
Currently, the public has a strong sense of the need for environment protection and the use of sustainable, or “green,” design in buildings and other civil structures. Since green design elements and technologies are different from traditional design, they probably have impacts on the building environment, such as vibration, lighting, noise, temperature, relative humidity, and overall comfort. Determining these impacts of green design on building environments is the primary objective of this study. The Zero Energy Research (ZOE) laboratory, located at the University of North Texas Discovery Park, is analyzed as a case study. Because the ZOE lab is a building that combines various green design elements and energy efficient technologies, such as solar panels, a geothermal heating system, and wind turbines, it provides an ideal case to study. Through field measurements and a questionnaire survey of regular occupants of the ZOE lab, this thesis analyzed and reported: 1) whether green design elements changed the building’s ability to meet common building environmental standards, 2) whether green design elements assisted in Leadership in Energy and Environmental Design (LEED) scoring, and 3) whether green design elements decreased the subjective comfort level of the occupants. digital.library.unt.edu/ark:/67531/metadc822831/
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/
Indirect Fabrication of Lattice Metals with Thin Sections Using Centrifugal Casting
There is a wide range of applications for 3D printing technology with an additive manufacturing such as aerospace, automotive, marine and oil/gas, medical, consumer, electronics, building construction, and many others. There have been many pros and cons for 3D additive manufacturing. Even though 3D printing technology has many advantages: freedom to design and innovate without penalties, rapid iteration through design permutations, excellence mass customization, elimination of tolling, green manufacturing, minimal material wastes, energy efficiency, an enablement of personalized manufacturing. 3D additive manufacturing still has many disadvantages: unexpected pre- and post-processing requirement, high-end manufacturing, low speed for mass production, high thermal residual stress, and poor surface finish and dimensional accuracy, and many others. Especially, the issues for 3D additive manufacturing are on high cost for process and equipment for high-end manufacturing, low speed for mass production, high thermal residual stress, and poor surface finish and dimensional accuracy. In particular, it is relatively challenging to produce casting products with lattice or honeycomb shapes having sophisticated geometries. In spite of the scalable potential of periodic cellular metals to structural applications, the manufacturing methods of I∙AM Casting have been not actively explored nor fully understood. A few qualitative studies of I∙AM Casting has been reported. Recently, a sand casting of cellular structures was attempted, resulting in casting porosity and the sharp corners in the lattice structure of the cellular structural molds, a sharpness which prevent fluid-flow and causes undesired solidification, resulting in misrun casting defects. Research on the indirect AM methods has not been aggressively conducted due to the highly complex and multidisciplinary problems across the process – continuum modeling (thermal stress, flow, heat transfer, and water diffusion) with multiple materials (polymer, metals, and ceramic) for multiphase simulations – solid, liquid, and gas. As an initial step to fully understand the processing of I∙AM Casting, a quantitative study on I∙AM Casting is conducted in this work. digital.library.unt.edu/ark:/67531/metadc822758/
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