UNT Theses and Dissertations - 8,070 Matching Results

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The Acute Toxic Effects of the Synthetic Cannabinoid, JWH-018 on the Cardiovascular and Neuroendocrine System in Ictalurus punctatus (Channel Catfish)

Description: Cannabinoid (CB) receptors have been found in most vertebrates that have been studied. The location of various CB receptors in the body and brain are known, but their physiological functions are not fully understood. The effects CBs have on the cardiovascular system have been of growing interest in recent years. Increasing reports from emergency departments and law enforcement agencies detail acute cardiovascular and psychological effects from synthetic CB intoxication, such as JWH-018. This major health concern is substantiated by governmental agencies like the CDC and NIDA. This pilot study investigates the acute toxic effects of the synthetic CB, JWH-018, on the cardiovascular and neuroendocrine systems in Ictalurus punctatus (channel catfish). Research in organisms besides the traditional mammal models can provide new insights into CB function and physiology. Ictalurus punctatus lend multiple benefits as a model organism that permits researchers to investigate in vivo effects of both cardiovascular and neuroendocrine systems without much influence from traditional sampling methods, and further more provide ample size and tissue to perform specific cardiovascular experiments. Multiple methods were used to assess cardiovascular function and sympathetic nervous system activation. Two different doses, low (500 µg/kg) and high 1,500 µg/kg, of JWH-018 were evaluated in the study. Delivery of JWH-018, via dorsal aorta cannulation, was administered to channel catfish in order to measure cardiovascular functions and sample blood. Plasma levels of the hypothalamus-pituitary-adrenal/interrenal (HPA/I) biomarkers; ACTH, cortisol, epinephrine, and norepinephrine, were measured using ELISAs. Myocardial and neural tissue was collected after the exposures for rt-PCR analysis on β2 adrenergic and glucocorticoid receptor density change. Acute exposure of JWH-018 in undisturbed channel catfish yielded several findings: (1) High dose of JWH-018 was responsible for cardio depressor effects in catfish with a tendency to produce tachycardia, (2) rt-PCR results showed a 2.7 fold increase of glucocorticoid receptor mRNA density ...
Date: August 2017
Creator: Taylor, Dedric Esmond
Partner: UNT Libraries

African American Soldiers in the Philippine War: An Examination of the Contributions of the Buffalo Soldiers during the Spanish American War and Its Aftermath, 1898-1902

Description: During the Philippine War, 1899 – 1902, America attempted to quell an uprising from the Filipino people. Four regular army regiments of black soldiers, the Ninth and Tenth Cavalry, and the Twenty-Fourth and Twenty-Fifth Infantry served in this conflict. Alongside the regular army regiments, two volunteer regiments of black soldiers, the Forty-Eighth and Forty-Ninth, also served. During and after the war these regiments received little attention from the press, public, or even historians. These black regiments served in a variety of duties in the Philippines, primarily these regiments served on the islands of Luzon and Samar. The main role of these regiments focused on garrisoning sections of the Philippines and helping to end the insurrection. To carry out this mission, the regiments undertook a variety of duties including scouting, fighting insurgents and ladrones (bandits), creating local civil governments, and improving infrastructure. The regiments challenged racist notions in America in three ways. They undertook the same duties as white soldiers. They interacted with local "brown" Filipino populations without fraternizing, particularly with women, as whites assumed they would. And, they served effectively at the company and platoon level under black officers. Despite the important contributions of these soldiers, both socially and militarily, little research focuses on their experiences in the Philippines. This dissertation will discover and examine those experiences. To do this, each regiment is discussed individually and their experiences used to examine the role these men played in the Philippine War. Also addressed is the role ideas about race played in these experiences. This dissertation looks to answer whether or not notions on race played a major role in the activities of these regiments. This dissertation will be an important addition to the study of the Philippine War, the segregated U. S. Army, and African American history in the modern period.
Date: August 2017
Creator: Redgraves, Christopher M.
Partner: UNT Libraries

"Among the Voices Voiceless": Setting the Words of Samuel Beckett

Description: Among the Voices Voiceless is a composition for flute (doubling piccolo), clarinet (doubling bass clarinet), viola, cello, percussion, piano, and electronics, based on the poem "What would I do without this world faceless incurious" by Samuel Beckett. The piece is a setting for disembodied voice: the vocal part exists solely in the electronics. Having no physical body, the voice is obscured as the point of empathy for the audience. In addition, instrumental solos compete for focus during the work's twenty minute duration. In passages including a soloist, the soloist functions simultaneously as antagonist and avatar to the disembodied voice. Spoken word recordings and electronic manipulation of instrumental material provides further layers of ambiguity. The companion critical essay "Among the Voices Voiceless": Setting the Words of Samuel Beckett proposes the distillation of Beckett's style into the elements of prosaicness, repetition, fragmentation, ambiguity, and symmetry. Discussions of Beckett's works such as Waiting for Godot and Molloy demonstrate these elements in his practice. This framework informs the examination of two other musical settings of Beckett's poetry: Neither by Morton Feldman and Odyssey by Roger Reynolds. Finally, these elements are used to analyze and elucidate the compositional decisions made in Among the Voices Voiceless.
Date: August 2017
Creator: Lyszczarz, Joseph E
Partner: UNT Libraries

Assessment of Competencies among Doctoral Trainees in Psychology

Description: The recent shift to a culture of competence has permeated several areas of professional psychology, including competency identification, competency-based education training, and competency assessment. A competency framework has also been applied to various programs and specialty areas within psychology, such as clinical, counseling, clinical health, school, cultural diversity, neuro-, gero-, child, and pediatric psychology. Despite the spread of competency focus throughout psychology, few standardized measures of competency assessment have been developed. To the authors' knowledge, only four published studies on measures of competency assessment in psychology currently exist. While these measures demonstrate significant steps in progressing the assessment of confidence, three of these measures were designed for use with individual programs, two of these international (i.e., UK and Taiwan). The current study applied the seminal Competency Benchmarks, via a recently adapted benchmarks form (i.e., Practicum Evaluation form; PEF), to practicum students at the University of North Texas. In addition to traditional supervisor ratings, the present study also involved self-, peer supervisor, and peer supervisee ratings to provide 360-degree evaluations. Item-response theory (IRT) was used to evaluate the psychometric properties of the PEF and inform potential revisions of this form. Supervisor ratings of competency were found to fit the Rasch model specified, lending support to use of the benchmarks framework as assessed by this form. Self- and peer-ratings were significantly correlated with supervisor ratings, indicating that there may be some utility to 360-degree evaluations. Finally, as predicted, foundational competencies were rated as significantly higher than functional competencies, and competencies improved significantly with training. Results of the current study provide clarity about the utility of the PEF and inform our understanding of practicum-level competencies.
Date: August 2017
Creator: Price, Samantha
Partner: UNT Libraries

A Case Study of Mathematics Teachers' Use of Short-Cycle Formative Assessment Strategies

Description: A single case study was used to examine two middle grades mathematics teachers' use of short-cycle formative assessment strategies. Data was collected using multiple sources to provide a description of this single case. Participant change in knowledge of short-cycle formative assessment strategies was collected and analyzed through participant pre- and post-interviews and targeted instructional support was provided through professional development sessions designed to meet diverse needs of participants. Participant change in use of short-cycle formative assessment strategies was collected and analyzed through classroom observations using Assess Today observation protocol and targeted instructional support was provided through post-observation conferences with written feedback. Findings from the study verified that changes in teachers' use of short-cycle formative assessment strategies were positively influenced by the targeted instructional support provided to each participant during the study. The study further indicated that an assessment of teacher's present knowledge and use of short-cycle formative assessment strategies should be considered before providing targeted instructional support to maximize the learning potential for each teacher. Future research is needed regarding the importance of building student self-efficacy through teacher use of short-cycle formative assessment, as well as the importance of involving students in the formative assessment process.
Date: August 2017
Creator: Davis, Adreana A
Partner: UNT Libraries

A Classification of the Homogeneity of Countable Products of Subsets of Real Numbers

Description: Spaces such as the closed interval [0, 1] do not have the property of being homogeneous, strongly locally homogeneous (SLH) or countable dense homogeneous (CDH), but the Hilbert cube has all three properties. We investigate subsets X of real numbers to determine when their countable product is homogeneous, SLH, or CDH. We give necessary and sufficient conditions for the product to be homogeneous. We also prove that the product is SLH if and only if X is zero-dimensional or an interval. And finally we show that for a Borel subset X of real numbers the product is CDH iff X is a G-delta zero-dimensional set or an interval.
Date: August 2017
Creator: Allen, Cristian Gerardo
Partner: UNT Libraries

Combining Select Blood-Based Biomarkers with Neuropsychological Assessment to Detect Mild Cognitive Impairment among Mexican Americans: A Molecular Neuropsychology Approach

Description: Mexican Americans face a significant health disparity related to the development of Mild Cognitive Impairment (MCI) when compared to other ethnic groups. Recent work has documented the utility of utilizing blood-based biomarkers in the detection of amnestic MCI among this population. Efforts to enhance the utility of biomarkers in detecting disease through the inclusion of select neuropsychological measures, an approach termed Molecular Neuropsychology, has shown promise. The present study sought to utilize the molecular neuropsychology approach and examine biobanked serum samples as well as neuropsychological assessments from the Health and Aging Brain among Latino Elders (HABLE) study. Random Forest analyses were conducted to determine the proteomic profile of MCI. Then separate linear regression analyses were conducted to determine the variance accounted for by the biomarkers within the select neuropsychological measures. Trail Making Test Part B was identified as having the least amount of variance and was combined with top five biomarkers within the MCI proteomic profile to create a biomarker-cognitive profile for detecting disease presence. This same method was applied to the amnestic and non-amnestic forms of MCI. The overall biomarker-cognitive profile was shown to be 90% accurate in the detection of MCI, with no significant increase when demographic variables were included into the model. Among amnestic MCI cases, the detection accuracy of the biomarker-cognitive profile was 92% and increased to 94% upon inclusion of demographic variables.
Date: August 2017
Creator: Edwards, Melissa
Partner: UNT Libraries

Community of Inquiry Meets Critical Discourse Analysis (CDA): A CDA of Asynchronous Computer-Conference Discourse with Seminary Students in India

Description: The purpose of this study was to better understand student learning in asynchronous computer-conference discourse (ASD) for non-native speakers of English in India through the Community of Inquiry (COI) framework. The study looked at ASD from an online course taught in the fall of 2015 to 25 students in a seminary in South India. All but one of the students were non-native speakers of English. The class consisted of 22 men and 3 women. Eight students spoke languages from the Dravidian family of languages (Malayalam, Tamil, Telegu and Kannada). Eight students were from the Northeastern states of Manipur, Nagaland and Tripura, where most languages are from the Sino-Tibetan family. Three students were native speakers of Indo-Aryan languages (Odiya and Assamese). Five students were from Myanmar representing several Sino-Tibetan languages. The COI is a framework used to understand learning in ASD, often used in online learning. To study the ASD of this group, critical discourse analysis (CDA) was used with the COI to capture the unique socio-cultural and linguistic conditions of this group. The study revealed that non-native speakers of English often reach the Exploration phase of learning but rarely show evidence of reaching the Resolution phase. This phenomenon was also observed in native English speakers as reported in the literature. Also, the structure of ASD showed that students took an examination approach to discussion shaped in part by their epistemology. This examination approach shaped how knowledge was constructed. CDA also showed that the discourse acquired an instructor-centered structure in which Resolution and Repair were initiated and finalized by the instructor. The study advances the COI framework by undergirding it with a theory of asynchronous discourse using critical discourse analysis and capturing cognitive, social and teaching presence phenomena for non-native speakers that were not observed through the traditional COI framework. These ...
Date: August 2017
Creator: George, Stephen J
Partner: UNT Libraries

Comparing Three Approaches for Handling a Fourth Level of Nesting Structure in Cluster-Randomized Trials

Description: This study compared 3 approaches for handling a fourth level of nesting structure when analyzing data from a cluster-randomized trial (CRT). CRTs can include 3 levels of nesting: repeated measures, individual, and cluster levels. However, above the cluster level, there may sometimes be an additional potentially important fourth level of nesting (e.g., schools, districts, etc., depending on the design) that is typically ignored in CRT data analysis. The current study examined the impact of ignoring this fourth level, accounting for it using a model-based approach, and accounting it using a design-based approach on parameter and standard error (SE) estimates. Several fixed effect and random effect variance parameters and SEs were biased across all 3 models. In the 4-level model, most SE biases decreased as the number of level 3 clusters increased and as the number of level 4 clusters decreased. Also, random effect variance biases decreased as the number of level 3 clusters increased. In the 3-level and complex models, SEs became more biased as the weight level 4 carried increased (i.e., larger intraclass correlation, more clusters at that level). The current results suggest that if a meaningful fourth level of nesting exists, future researchers should account for it using design-based approach; the model-based approach is not recommended. If the fourth level is not practically important, researchers may ignore it altogether.
Date: August 2017
Creator: Glaman, Ryan
Partner: UNT Libraries

Comparison of the "Méthode Pour La Guitare" by Fernando Sor with the "Méthode Complète Pour La Guitare Par Ferdinand Sor, Rédigée Et Augmentée De Nombreux Exemples Et Leçons Suivis D'une Notice Sur La 7e Corde" by Napoléon Coste

Description: The nineteenth century presents a great increase in publications of guitar methods. Most authors of the time published several versions of their works. Fernando Sor, perhaps the most prominent guitar composers of the time—whose Méthode is regarded today as the most important of the period—only published one edition. However, Napoleon Coste took on the task to do a second account. The literature reviewed shows substantial existing information regarding background, type of text, tone, and contents of Sor's work, but comparisons to date are not substantial. Therefore, there is a need to compare these two texts side by side to yield a complete view of their pairing. The existing negative views of Coste's edition hinder the importance of Coste's work as reference to Segovia's publication of Sor studies, and as a clearer pedagogical application of many of Sor's concepts which are sidetracked by his response to criticism and his elaborations in matters beyond his main subject matter. I provide a comprehensive review of Sor's method, an outline and a consideration of his concepts. Then I offer a complete English translation of Coste's method which is inexistent until now. The comparison follows pointing at differences and similarities. Results show that Coste clarifies and complements many of the principles in less text and simpler language. He modifies certain others either to approach Sor's practice or to depart to a newer standard. He offers his own lessons and sections to apply Sor's concepts. Coste's text heads towards a pedagogical synthesis of Sor's method, but it is incomplete because he omits some concepts without leading the readers to consult Sor. Coste's pedagogical and practical relevance is fundamental for modern standard techniques.
Date: August 2017
Creator: Rodriguez, Sergio
Partner: UNT Libraries

A Comprehensive Performance Guide for the Use of Advanced Technology in Euphonium Repertoire with Electronic Media through Analyses of Works by D. Edward Davis, Neal Corwell, and Lucy Pankhurst

Description: Solos for euphonium with electronic media present the unique challenge of incorporating an active, physical involvement in the live accompaniment through sound-altering technology such as guitar pedals or digital processors. Instructions for this solo genre are often vague and demand a general knowledge of how to use non-traditional devices. Due to the lack of information available on newly-composed pieces for this medium, students and professionals easily overlook the artistic merit of electroacoustic music. This dissertation provides a comprehensive performance guide that aids in the set-up and operation of advanced technology and presents a methodical approach to performing common musical and technical challenges found in modern euphonium repertoire with electronic media. Included in this dissertation are tables of common audio vocabulary and images of connectors, safety precautions, equipment recommendations with performance settings, a list of required connectors, adapters, cables, speakers, and amplifiers, performance set up diagrams, background information, and analyses of both the technical and musical aspects of each piece. In the appendices are signal flow charts, visual illustrations of polar recording patterns, and an updated catalog of published and unpublished original, adapted, and arranged euphonium solos with live electronics and electronic media accompaniment between 1970 and 2017.
Date: August 2017
Creator: Ray, Irving
Partner: UNT Libraries

Controlled Vocabularies in the Digital Age: Are They Still Relevant?

Description: Keyword searching and controlled vocabularies such as Library of Congress subject headings (LCSH) proved to work well together in automated technologies and the two systems have been considered complimentary. When the Internet burst onto the information landscape, users embraced the simplicity of keyword searching of this resource while researchers and scholars seemed unable to agree on how best to make use of controlled vocabularies in this huge database. This research looked at a controlled vocabulary, LCSH, in the context of keyword searching of a full text database. The Internet and probably its most used search engine, Google, seemed to have set a standard that users have embraced: a keyword-searchable single search box on an uncluttered web page. Libraries have even introduced federated single search boxes to their web pages, another testimony to the influence of Google. UNT's Thesis and Dissertation digital database was used to compile quantitative data with the results input into an EXCEL spreadsheet. Both Library of Congress subject headings (LCSH) and author-assigned keywords were analyzed within selected dissertations and both systems were compared. When the LCSH terms from the dissertations were quantified, the results showed that from a total of 788 words contained in the 207 LCSH terms assigned to 70 dissertations, 246 of 31% did not appear in the title or abstract while only 8, or about 1% from the total of 788, did not appear in the full text. When the author-assigned keywords were quantified, the results showed that from a total of 552 words from304 author-assigned keywords in 86 dissertations, 50 or 9% did not appear in the title or abstract while only one word from the total of 552 or .18% did not appear in the full text. Qualitatively, the LCSH terms showed a hierarchical construction that was clearly designed for a print ...
Date: August 2017
Creator: Baker, William
Partner: UNT Libraries

Crossing Over: Essays on Ethnic Parties, Electoral Politics, and Ethnic Social Conflict

Description: This dissertation analyzes several topics related to political life in ethnically divided societies. In chapter 2, I study the relationship between ethnic social conflict, such as protests, riots, and armed inter-ethnic violence, and bloc partisan identification. I find that protests have no effect on bloc support for political parties, riots increase bloc partisan identification, and that armed violence reduces this phenomenon. In chapter 3, I analyze the factors that influence the targeting of ethnic groups by ethnic parties in social conflict. I find some empirical evidence that conditions favorable to vote pooling across ethnic lines reduce group targeting by ethnic parties. In chapter 4, I analyze the effects of ethnic demography on ethnic party behavior. Through a qualitative analysis of party behavior in local elections in Macedonia, I find that ethnic parties change their strategies in response to changes in ethnic demography. I find that co-ethnic parties are less likely to challenge each other for power under conditions of split demography. In fact, under conditions of split demography, I find that co-ethnic parties have political incentives to unite behind a single party because intra-group competition jeopardizes the group's hold on power.
Date: August 2017
Creator: Stewart, Brandon
Partner: UNT Libraries

Crystallographic Complex Reflection Groups and the Braid Conjecture

Description: Crystallographic complex reflection groups are generated by reflections about affine hyperplanes in complex space and stabilize a full rank lattice. These analogs of affine Weyl groups have infinite order and were classified by V.L. Popov in 1982. The classical Braid theorem (first established by E. Artin and E. Brieskorn) asserts that the Artin group of a reflection group (finite or affine Weyl) gives the fundamental group of regular orbits. In other words, the fundamental group of the space with reflecting hyperplanes removed has a presentation mimicking that of the Coxeter presentation; one need only remove relations giving generators finite order. N.V Dung used a semi-cell construction to prove the Braid theorem for affine Weyl groups. Malle conjectured that the Braid theorem holds for all crystallographic complex reflection groups after constructing Coxeter-like reflection presentations. We show how to extend Dung's ideas to crystallographic complex reflection groups and then extend the Braid theorem to some groups in the infinite family [G(r,p,n)]. The proof requires a new classification of crystallographic groups in the infinite family that fail the Steinberg theorem.
Date: August 2017
Creator: Puente, Philip C
Partner: UNT Libraries

Design, Synthesis and Optoelectronic Properties of Monovalent Coinage Metal-Based Functional Materials toward Potential Lighting, Display and Energy-Harvesting Devices

Description: Groundbreaking progress in molecule-based optoelectronic devices for lighting, display and energy-harvesting technologies demands highly efficient and easily processable functional materials with tunable properties governed by their molecular/supramolecular structure variations. To date, functional coordination compounds whose function is governed by non-covalent weak forces (e.g., metallophilic, dπ-acid/dπ-base stacking, halogen/halogen and/or d/π interactions) remain limited. This is unlike the situation for metal-free organic semiconductors, as most metal complexes incorporated in optoelectronic devices have their function determined by the properties of the monomeric molecular unit (e.g., Ir(III)-phenylpyridine complexes in organic light-emitting diodes (OLEDs) and Ru(II)-polypyridyl complexes in dye-sensitized solar cells (DSSCs)). This dissertation represents comprehensive results of both experimental and theoretical studies, descriptions of synthetic methods and possible application allied to monovalent coinage metal-based functional materials. The main emphasis is given to the design and synthesis of functional materials with preset material properties such as light-emitting materials, light-harvesting materials and conducting materials. In terms of advances in fundamental scientific phenomena, the major highlight of the work in this dissertation is the discovery of closed-shell polar-covalent metal-metal bonds manifested by ligand-unassisted d10-d10 covalent bonds between Cu(I) and Au(I) coinage metals in the ground electronic state (~2.87 Å; ~45 kcal/mol). Moreover, this dissertation also reports pairwise intermolecular aurophilic interactions of 3.066 Å for an Au(I) complex, representing the shortest ever reported pairwise intermolecular aurophilic distances among all coinage metal(I) cyclic trimetallic complexes to date; crystals of this complex also exhibit gigantic luminescence thermochromism of 10,200 cm-1 (violet to red). From applications prospective, the work herein presents monovalent coinage metal-based functional optoelectronic materials such as heterobimetallic complexes with near-unity photoluminescence quantum yield, metallic or semiconducting integrated donor-acceptor stacks and a new class of Au(III)-based black absorbers with cooperative intermolecular iodophilic (I…I) interactions that sensitize the harvesting of all UV, all visible, and a broad spectrum of near-IR ...
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Date: August 2017
Creator: Ghimire, Mukunda Mani
Partner: UNT Libraries

Developing a Phylogeny Based Machine Learning Algorithm for Metagenomics

Description: Metagenomics is the study of the totality of the complete genetic elements discovered from a defined environment. Different from traditional microbiology study, which only analyzes a small percent of microbes that could survive in laboratory, metagenomics allows researchers to get entire genetic information from all the samples in the communities. So metagenomics enables understanding of the target environments and the hidden relationships between bacteria and diseases. In order to efficiently analyze the metagenomics data, cutting-edge technologies for analyzing the relationships among microbes and communities are required. To overcome the challenges brought by rapid growth in metagenomics datasets, advances in novel methodologies for interpreting metagenomics data are clearly needed. The first two chapters of this dissertation summarize and compare the widely-used methods in metagenomics and integrate these methods into pipelines. Properly analyzing metagenomics data requires a variety of bioinformatcis and statistical approaches to deal with different situations. The raw reads from sequencing centers need to be processed and denoised by several steps and then be further interpreted by ecological and statistical analysis. So understanding these algorithms and combining different approaches could potentially reduce the influence of noises and biases at different steps. And an efficient and accurate pipeline is important to robustly decipher the differences and functionality of bacteria in communities. Traditional statistical analysis and machine learning algorithms have their limitations on analyzing metagenomics data. Thus, rest three chapters describe a new phylogeny based machine learning and feature selection algorithm to overcome these problems. The new method outperforms traditional algorithms and can provide more robust candidate microbes for further analysis. With the frowing sample size, deep neural network could potentially describe more complicated characteristic of data and thus improve model accuracy. So a deep learning framework is designed on top of the shallow learning algorithm stated above in order to further ...
Date: August 2017
Creator: Rong, Ruichen
Partner: UNT Libraries

Developing a Self-Respect Instrument to Distinguish Self-Respect from Self-Esteem

Description: Throughout the scientific literature, researchers have referred to self-respect and self-esteem as being the same construct. However, the present study advocated that they exist as two distinct constructs. In this quantitative study, an instrument was developed to measure self-respect as a construct, and subsequently distinguish that self-respect is distinct from the construct of self-esteem. Exploratory factor analyses (EFA) indicated 32.60% of the variance was accounted for by the 11-item Jefferson Self-Respect instrument (JSR), which measured self-respect as a unidimensional construct. The reliability estimate of the scores from the JSR reached an acceptable α = .82. Fit indices (RMSEA = .031, SRMR = .037, CFI = .982, and TLI = .977) from the confirmatory factor analyses (CFA) signified a well-fitted hypothesized model of self-respect that existed as a unidimensional construct. Additionally, the CFA revealed that the construct of self-respect, and self-esteem was generally distinct, and the strength of the correlation between the two constructs was moderately positive (r = .62).
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Date: August 2017
Creator: Jefferson, Sean G
Partner: UNT Libraries

Developing Precipitation Hardenable High Entropy Alloys

Description: High entropy alloys (HEAs) is a concept wherein alloys are constructed with five or more elements mixed in equal proportions; these are also known as multi-principle elements (MPEs) or complex concentrated alloys (CCAs). This PhD thesis dissertation presents research conducted to develop precipitation-hardenable high entropy alloys using a much-studied fcc-based equi-atomic quaternary alloy (CoCrFeNi). Minor additions of aluminium make the alloy amenable for precipitating ordered intermetallic phases in an fcc matrix. Aluminum also affects grain growth kinetics and Hall-Petch hardenability. The use of a combinatorial approach for assessing composition-microstructure-property relationships in high entropy alloys, or more broadly in complex concentrated alloys; using laser deposited compositionally graded AlxCrCuFeNi2 (0 < x < 1.5) complex concentrated alloys as a candidate system. The composition gradient has been achieved from CrCuFeNi2 to Al1.5CrCuFeNi2 over a length of ~25 mm, deposited using the laser engineered net shaping process from a blend of elemental powders. With increasing Al content, there was a gradual change from an fcc-based microstructure (including the ordered L12 phase) to a bcc-based microstructure (including the ordered B2 phase), accompanied with a progressive increase in microhardness. Based on this combinatorial assessment, two promising fcc-based precipitation strengthened systems have been identified; Al0.3CuCrFeNi2 and Al0.3CoCrFeNi, and both compositions were subsequently thermo-mechanically processed via conventional techniques. The phase stability and mechanical properties of these alloys have been investigated and will be presented. Additionally, the activation energy for grain growth as a function of Al content in these complex alloys has also been investigated. Change in fcc grain growth kinetic was studied as a function of aluminum; the apparent activation energy for grain growth increases by about three times going from Al0.1CoCrFeNi (3% Al (at%)) to Al0.3CoCrFeNi. (7% Al (at%)). Furthermore, Al addition leads to the precipitation of highly refined ordered L12 (γ′) and B2 precipitates in ...
Date: August 2017
Creator: Gwalani, Bharat
Partner: UNT Libraries

"Drum Music": A Performance Guide and Discussion of John Mackey's Influential Concerto for the Modern Percussionist

Description: John Mackey is an influential and prolific composer of wind band literature. His focus on and exploration of the percussion section are defining characteristics of his compositional voice. Mackey's concerto for percussion and wind band, "Drum Music," is a perfect example of his exploitation of the myriad timbres available within the percussion family, and also serves to showcase the versatility required of a modern percussionist. This dissertation and accompanying lecture recital provide a comprehensive guide for performers of the work. Major aspects of Mackey's compositional approach are discussed with emphasis placed on his use of percussion throughout his works. Analysis and performance concerns are discussed for each of the concertos three movements, and information is provided on the reduced version of the work prepared as part of this study.
Date: August 2017
Creator: McWilliams, Christopher Wayne
Partner: UNT Libraries

Educational Uplift along the US-Mexico Border: How Students, Families, and Educators Cultivate a College-Going Culture in Contested Terrain

Description: Using critical race theory and LatCrit as conceptual frameworks, I conducted a qualitative instrumental case study of a cadre of self-identified Mexican-American and Hispanic college students who bring college knowledge, goodwill, and aid to their border town communities. The purpose of this study was to explore how college knowledge and other forms of academic capital are transmitted and co-constructed in the contested terrain of the borderlands. Primary data sources included semi-structured interviews, participant and non-participant observation, and personal artifacts (e.g. newspaper articles, college admissions essays, social media, etc.) collected from 17 full-time undergraduate student participants, 11 males and 6 females, ranging from 19 to 22 years old, who were active members of the Gates Millennium Scholars Program. Supplemental data sources included semi-structured interviews with 23 family members and 9 educators identified by student participants, as well as a review of public records regarding student participant's border town communities (e.g. newspaper articles, census data, educational statistics, etc.). Findings detail how this group of college students manages the 'scholar' distinction in their hometown and utilizes distinct methods to promote academic capital formation. Specifically, this study delineates the following four types of scholars: (1) pioneers, (2) guardians, (3) ambassadors, and (4) advocates. Ultimately, this research highlights the importance of college students' ingenuity in response to enduring system inequality in higher education, particularly along the U.S.-Mexico border, with implications for research theory, policy, and practice.
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Date: August 2017
Creator: Sanchez, Nydia C
Partner: UNT Libraries

The Effect of Instructional Expenditures on College Readiness

Description: With limited state and local funds as well as a growing student population, how elected decision makers allocate money to impact college readiness needs to be explored. The purpose of this research study was to explore the impact of instructional expenditures on educational outcomes. This multivariate multiple regression study specifically explored the impact of instructional expenditure ratios and per pupil instructional expenditures of every public school district in Texas on student performance college readiness indicators measured by state assessments (State of Texas Assessment of Academic Readiness [STAAR] Mathematics and English Language Arts [ELA] test scores) and national assessments (American College Test [ACT] and Scholastic Assessment Test [SAT] scores) over a 5-year period. Fifteen different regression models were established with various significant predictors of expenditures and revenue funds. These models explained up to 46% of the variance for college readiness scores over the 5-year period.
Date: August 2017
Creator: Blair, Cody
Partner: UNT Libraries

Elections and Authoritarian Rule: Causes and Consequences of Adoption of Grassroots Elections in China

Description: This dissertation investigates the relationship between elections and authoritarian rule with a focus on the case of China's adoption of elections at the grassroots level. In this dissertation, I look at the incentives facing Chinese local governments in choosing between holding competitive elections or state-controlled elections, and how the selection of electoral rules shapes the public's preferences over political institutions and influences the citizens' political behaviors, especially voting in elections and participation in contentious activities. The overarching theme in this dissertation proposes that the sources and consequences of Chinese local elections are conditioned on the state-owned resources and the governing costs. When the amount of state-owned resources to rule the local society is limited, the paucity of resources will incentivize authoritarian governments to liberalize grassroots elections to offset the governance costs. The various levels of election liberalization will lead to different consequences in the public's political behavior. An abundance of state-owned resources not only discourages rulers from sharing power with the local society, but also supplies the rulers with strong capacity to obtain loyalty from voters when elections are adopted. As a result, elections under authoritarian governments with an abundance of state-owned resources will see more loyalist voters than elections with authoritarian governments with fewer state-owned resources. In addition, the varieties of election practices will exert impacts on public opinion toward the authoritarian government: awareness of elections will enhance public trust in the government and decrease the public's intention to challenge the incumbents' authority while at the same time increasing the public's faith in the institutions, thereby encouraging the public to adopt official channels to air their grievances. The analysis of the village-level as well as individual-level survey data and cases lends empirical supports to the argument. First, I find that the governing costs—measured by the size of labor force—are ...
Date: August 2017
Creator: Tzeng, Wei Feng
Partner: UNT Libraries

The Evolution of Brand Co-Creation: Models and Exploration of Stakeholders' Motivations

Description: Co-creation is an emerging phenomenon that occurs when two or more parties work together to create value. Co-creation, which is a key component to service dominant logic, is present in business to business, business to consumer, and consumer to consumer processes. This dissertation will focus on the business to consumer (and consumer to business) co-creation relationship. Much of the current business to consumer co-creation literature is qualitative in nature, with quantitative work just now beginning to emerge. As such, there is still much about the phenomenon of co-creation that is not understood. When looking at co-creation in the context of brand management, even less is known. In today's age of digital interaction where consumers are gaining more power on a daily basis, practitioners and academics should understand the motivations for consumers to engage brands in co-creation and what the outcomes of these co-creation partnerships are. Because of this, the dissertation contains three essays with the purpose of (1) identifying the motivations for co-creation from consumer and brand perspectives, (2) exploring each of these motivators on their individual relationship to the outcome of co-creation, and (3) understanding how the perceived ability to influence a brand impacts the outcomes of co-creation. Essay 1, titled "Co-creation of brand identities: consumer and industry influence and motivations," aims to develop an understanding of the phenomena of co-creation and how the practice is used in shaping brand identities. Two studies are undertaken to provide insight into co-creation. First, a qualitative study is used to gain insight from key decision makers with responsibility for a brand. Second, a study of millennial consumers is used to develop the antecedents of consumer motivations of co-creation of brand identities. This essay then presents a comprehensive framework that encompasses two models (industry and consumer) of brand identity co-creation. Much of the ...
Date: August 2017
Creator: Kennedy, Eric
Partner: UNT Libraries

The Evolution of Learning Technologies within the UNC German Consortium 2000-2016: A Hermeneutic Phenomenlogical Analysis of German Faculty Member Experiences

Description: Beginning in 2000 and continuing today, the University of North Carolina (UNC) German Consortium offers online German courses to undergraduate students across sixteen of the seventeen UNC public universities. The delivery of online classes differs per faculty member and little previous research investigated the UNC German Consortium's learning technologies. This dissertation investigates the evolution of learning technologies within the UNC German Consortium over the last sixteen years among German faculty from different UNC public universities. Seven faculty and one administrator shared their experiences through interviews. The methodology for this research was hermeneutic phenomenology. Interviewees shared their experiences with learning technology and teaching in the UNC German Consortium including how learning technologies changed over time. Interviews were transcribed, coded, and analyzed to deduce themes. Themes included the importance of the North Carolina Research Education Network (NC REN) for teaching German online, an asynchronous versus synchronous debate, how professors taught in synchronous courses, the importance of learning management systems (LMS) systems, the resilient characteristics of UNC German Consortium faculty, and the need for continual learning as an instructor.
Date: August 2017
Creator: Underwood, Zackary Wayne
Partner: UNT Libraries