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Processing-Structure-Property Relationships of Reactive Spark Plasma Sintered Boron Carbide-Titanium Diboride Composites

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Sintering parameter effects on the microstructure of boron carbide and boron carbide/titanium diboride composites are investigated. The resulting microstructure and composition are characterized by scanning electron microscopy (SEM), x-ray microscopy (XRM) and x-ray diffraction (XRD). Starting powder size distribution effects on microstructure are present and effect the mechanical properties. Reactive spark plasma sintering introduces boron nitride (BN) intergranular films (IGF's) and their effects on fracture toughness, hardness and flexural strength are shown. Mechanical testing of Vickers hardness, 3-point bend and Chevron notch was done and the microstructural effects on the resulting mechanical properties are investigated.
Date: August 2019
Creator: Lide, Hunter
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Charpy Impact Testing of Twinning Induced Plasticity and Transformation Induced Plasticity High Entropy Alloys

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High entropy alloys (HEAs) are a new class of solid solution alloys that contain multiple principal elements and possess excellent mechanical properties, from corrosion resistance to fatigue and wear resistance. Even more recently, twinning induced plasticity (TWIP) and transformation induced plasticity (TRIP) non-equiatomic high entropy alloys have been engineered, promising increased strength and ductility as compared to their equiatomic counterparts. However, impact and fracture resistance of these HEAs has not been studied as much as their other mechanical properties. In this thesis, the hardness, tensile properties, and Charpy impact energy of Al0.3CoCrFeNi, a TWIP HEA, and 50Fe-30Mn-10Co-10Cr (at.%), a TRIP HEA, was explored. First, three processing conditions, (1) as-received, (2) recrystallized, and (3) peak hardness, were chosen for each alloy and verified with Vickers microhardness measurements. Next, the tensile properties of each alloy and condition were investigated. Charpy impact specimen size was then selected based on the final plate thickness, and the machined samples were tested. Plastic zone size and change in sample thickness in the deformed region of each condition after testing was measured. Post-impact test inspection of the samples in all conditions showed that the samples were in tension near the V-notch root and in compression at the …
Date: August 2019
Creator: Zellner, Samantha R
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Enhanced Approach for the Classification of Ulcerative Colitis Severity in Colonoscopy Videos Using CNN

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Ulcerative colitis (UC) is a chronic inflammatory disease characterized by periods of relapses and remissions affecting more than 500,000 people in the United States. To achieve the therapeutic goals of UC, which are to first induce and then maintain disease remission, doctors need to evaluate the severity of UC of a patient. However, it is very difficult to evaluate the severity of UC objectively because of non-uniform nature of symptoms and large variations in their patterns. To address this, in our previous works, we developed two different approaches in which one is using the image textures, and the other is using CNN (convolutional neural network) to measure and classify objectively the severity of UC presented in optical colonoscopy video frames. But, we found that the image texture based approach could not handle larger number of variations in their patterns, and the CNN based approach could not achieve very high accuracy. In this paper, we improve our CNN based approach in two ways to provide better accuracy for the classification. We add more thorough and essential preprocessing, and generate more classes to accommodate large variations in their patterns. The experimental results show that the proposed preprocessing can improve the overall accuracy …
Date: August 2019
Creator: Sure, Venkata Leela
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Mining Biomedical Data for Hidden Relationship Discovery

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With an ever-growing number of publications in the biomedical domain, it becomes likely that important implicit connections between individual concepts of biomedical knowledge are overlooked. Literature based discovery (LBD) is in practice for many years to identify plausible associations between previously unrelated concepts. In this paper, we present a new, completely automatic and interactive system that creates a graph-based knowledge base to capture multifaceted complex associations among biomedical concepts. For a given pair of input concepts, our system auto-generates a list of ranked subgraphs uncovering possible previously unnoticed associations based on context information. To rank these subgraphs, we implement a novel ranking method using the context information obtained by performing random walks on the graph. In addition, we enhance the system by training a Neural Network Classifier to output the likelihood of the two concepts being likely related, which provides better insights to the end user.
Date: August 2019
Creator: Dharmavaram, Sirisha
Object Type: Thesis or Dissertation
System: The UNT Digital Library

The Effects of Benefit Types on Customer Loyalty in Integrated Resorts

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This study examined the relationships between the six benefit types and customer loyalty through trust and satisfaction in integrated resorts. A self-administered survey was developed based on previous studies in customer loyalty and was distributed through e-Reward online survey panel. The findings showed that only financial gaming benefits, functional gaming benefits, and psychological non-gaming benefits had impacts on customer attitudinal loyalty and customer behavioral loyalty through trust and satisfaction in integrated resorts. Besides, functional gaming benefits had the most influence on customer loyalty through trust and satisfaction. This study extended existing literature in integrated resorts by showing that benefit types in a loyalty program can build customer attitudinal loyalty and customer behavioral loyalty in integrated resorts. This study also examined different types of benefits affect customer loyalty in different degrees. For operators of integrated resorts, understanding how different benefits of a loyalty program affect customer loyalty will allow them to modify their loyalty programs effectively to increase revenue and maintain customers.
Date: August 2019
Creator: Su, Hsiang Wen
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Comparing Cognitive Functioning in White Mexican/Mexican Americans and non-Hispanic White Americans with and without Type 2 Diabetes

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To better understand the impact of type 2 diabetes, the relationship between ethnicity, specifically Mexican/Mexican American ethnicity, and the disease must be further investigated. This study specifically examined the cognitive impact of type 2 diabetes. Data from the 2014 Health and Retirement Study was used to compare the cognitive functioning of non-Hispanic White (n = 10,658) and White Mexican/Mexican American (n = 847) individuals, age 50+ years, with and without type 2 diabetes. Serial 7's and immediate and delayed recall—hypothesized to be more negatively affected by type 2 diabetes and Mexican American status—was compared controlling for age, education, and depression. A multivariate analysis of covariance (MANCOVA) indicated significant main effects for race/ethnicity (F(3,11496) = 11.15, p < .001) and diabetes status (F(3,11496) = 3.15, p < .024), with Mexican Americans and those with diabetes having worse cognitive performance. There were significant effects for all covariates. A step-wise multiple regression indicated that education, age, depression, race/ethnicity and diabetes status accounted for a combined 28.4% of variance in a cognitive performance composite. Implications for assessment and treatment are discussed.
Date: August 2019
Creator: Saldana, Samantha Lee
Object Type: Thesis or Dissertation
System: The UNT Digital Library

The Geography of Retail Clinics Post Implementation of the Affordable Care Act

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Retail clinics are walk-in clinics designed for convenience and for servicing minor health issues and certain acute conditions. The model began as a way of bringing both convenience and care to areas that have lower levels of access to primary care resources. With the implementation of Affordable Care Act (ACA) in March 2010, populations that were previously uninsured were now required to have access to some level of health insurance. These populations presented a potential new market for retail clinics. This research shows that post implementation of the ACA, retail clinics tend to locate in areas with higher incomes and, generally, greater access to primary care.
Date: August 2019
Creator: Portillo, Ethan
Object Type: Thesis or Dissertation
System: The UNT Digital Library

489 Days

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489 Days is an animated documentary about the harrowing experiences of Egyptian-American Mohamed Soltan, who survived 16 months of hunger strike in an Egyptian prison. Caught up in the political turmoil which followed the Arab Spring uprisings, Soltan was unjustly incarcerated between August 2013 and May 2015, when the United States government intervened to release him weeks after an Egyptian court sentenced him to life in prison. The film is also the larger story of an estimated 60,000 political detainees currently held in Egypt without due process, and in violation of local and international human rights conventions.
Date: August 2019
Creator: Elmalky, Rania
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Weapons of Mass Deception: Opacity and the Israeli Nuclear Program

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Access to nuclear technology and growing concern over the spread of nuclear weapons triggered an international debate in the 1960s that led to the creation of the Nonproliferation Treaty. Ratified in 1970, NPT was designed to prevent the horizontal spread of nuclear weapons and limit destructive uses of nuclear energy. At the same time, it also normalized the arsenals of existing nuclear states and encouraged exchanges of nuclear information, technology, and materials for peaceful purposes. Nonproliferation policy relies on a theory of the development process that identifies a nuclear frontier to locate evidence of nuclear capabilities. Absent from the proliferation model, however, are cases of covert nuclear weapons programs. For almost 50 years, it has been generally accepted that Israel is a nuclear weapon state, yet Israeli officials have never confirmed nor denied the possession of nuclear weapons. Israel has not signed NPT and has not appeared to conduct a nuclear test, in effect absolving the nuclear program's main reactor from international inspections. Uncertainty surrounding the Israeli program stems from a tradition of deliberate secrecy and deception that constitutes a national policy of opacity. This study argues that opacity has armed Israel with the privilege of nuclear immunity, exempting its …
Date: August 2019
Creator: Beattie, Kathleen E
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Lookouts

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Lookouts follows Matt and Joann, two fire tower lookouts for the United States Forest Service, as they discuss their happiness living in seclusion as well as the decline of fire towers due to technological advances.
Date: August 2019
Creator: Dejarnett, Claire
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Dynamic Deformation and Shear Localization in Friction-Stir Processed Al0.3CoCrFeNi and Fe50Mn30Co10Cr10 High-Entropy Alloys

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High entropy alloys (HEAs) are a relatively new class of solid solution alloys that contain multiple principal elements to take advantage of their high configurational entropy, sluggish diffusion, lattice distortion, and the cocktail effect. In recent development, work hardening mechanisms known as twinning induced plasticity (TWIP) and transformation induced plasticity (TRIP) have been found active in Al0.3CoCrFeNi (molar fraction) and Fe50Mn30Co10Cr10 (at %) HEA compositions. Friction-stir processing was done to increase the mechanical properties and improve the microstructure of the alloys for the purpose of high strain rate performance. Quasi-static tensile tests as well as top-hat geometry Split-Hopkinson pressure bar tests were conducted to view the mechanical properties as well as view the microstructural evolution at dynamic strain rates. Overall, the Al0.3CoCrFeNi condition after friction-stir processing and heat treatment has proved to have the best mechanical properties, and selecting from the conditions in this study, Al0.3CoCrFeNi has better shear localization resistance.
Date: August 2019
Creator: Macdonald, Neil
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Psychological Well-Being and Family Functioning in Middle Childhood: The Unique Role of Sibling Relational Dynamics

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The current study examined associations between perceived family functioning, sibling relational dynamics, and individual's self-reported personal adjustment and internalizing problems among 8- to 11-year old children. Path analyses revealed significant direct effects between conflictual family functioning and children's psychological well-being (p < 0.05). Further, sibling conflict was found to indirectly affect these associations. Finally, significant interactions between family functioning and sibling dynamics were found suggesting that congruent relational dynamics at multiple levels of the family system had a cumulative impact on the child's well-being. Findings from the current study highlight the unique contributions of sibling relationships to the family and the child providing evidence for targeting the sibling relationship in clinical interventions and future family research.
Date: August 2019
Creator: Geerts, Ashley T.
Object Type: Thesis or Dissertation
System: The UNT Digital Library

A Multimedia Atlas of Dissection for Comparative Anatomy of the Vertebrates

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This interactive multimedia content is part of a Master's thesis regarding how traditional methods of teaching the laboratory course for Comparative Anatomy of the Vertebrates could be improved by applying current computer technology to construct an interactive, multimedial atlas of dissection. Five specimens used in comparative anatomy courses at most institutions were chosen as representative members of the Phylum Chordata: amphioxus, lamprey, dogfish shark, mud puppy, and cat. Specimens were dissected according to the modified method of Wischnitzer, 1993, and each stage was photographed with a Kodak DC120 digital zoom camera. These images were processed on a Power Macintosh 7600 computer with Adobe Photoshop v. 5.0. The atlas was constructed from these images using Macromedia Authorware v. 4.0.3. Each image contains a series of interactive objects that display a highlight and descriptive text as the cursor passes over each object.
Date: August 1999
Creator: Curran, Anthony A., Jr.
Object Type: Interactive Resource
System: The UNT Digital Library

Master's Recital: 2007-08-01 - Jason Harron, alto and tenor saxophone

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Recital presented at the UNT College of Music Concert Hall.
Date: August 1, 2007
Creator: Harron, Jason
Object Type: Sound
System: The UNT Digital Library

Die Neue Lehre: Developing an Online Course in Schenkerian Analysis

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With the proliferation of Schenkerian theory in the US, Great Britain, and mainland Europe in the past quarter century, the pedagogy of Schenkerian analysis has become an important issue. Schenker himself was suspicious of textbooks with their tendency for artificial codification and over-simplification; rather, he recognized that his “New Teaching” (“Die neue Lehre”) – as he called it – required a different, more “organic” pedagogical approach that was both personal and yet accessible to a wide audience. New digital technologies and the Internet now have made it possible to disseminate Schenker’s pedagogical approach by adapting interactive techniques of Web-based instruction. Schenker’s “new teaching” was as organic as his theory itself – and as novel in the connections it sought to draw between the individualed disciplines of theory, musicology, composition, and performance. The interactive and multi-media components of Web-based instruction enable us to realize Schenker’s own pedagogical approach to Schenkerian analysis instruction.
Date: August 2001
Creator: Sadoff, Jennifer
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Process, Form, and Function

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Process and form have always been important to my work. I emphasize the soft qualities of clay while working with traditional forms that are altered for visual interest. Usability is very important, the forms have to function well according to their intended use. The relationship between form and manipulation relied on usability of the form. Functionality was paramount within this body of work. I consciously searched for balance between form and manipulation, form and glaze, form and function, and overall character. Though altered, the forms were traditional and dependent on function. Manipulations of the forms, surface treatment, and deep colorful glazes contributed to creating harmony between function and expression. Personal stylistic elements became refined through working on this project. The body of work that was made allocated personal expression and new variations on functional forms. This project provided an opportunity for exploration and evaluation of form and my working process.
Date: August 2001
Creator: Platt, Allyson
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Gestural Expressions in Clay

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The nature of clay's physical attributes and the application of these characteristics to an expression of gestural movement in utilitarian ceramics.
Date: August 2001
Creator: Neergaard, Nancy Dart
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Evaluation of hydrogen trapping in HfO2 high-κ dielectric thin films.

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Hafnium based high-κ dielectrics are considered potential candidates to replace SiO2 or SiON as the gate dielectric in complementary metal oxide semiconductor (CMOS) devices. Hydrogen is one of the most significant elements in semiconductor technology because of its pervasiveness in various deposition and optimization processes of electronic structures. Therefore, it is important to understand the properties and behavior of hydrogen in semiconductors with the final aim of controlling and using hydrogen to improve electronic performance of electronic structures. Trap transformations under annealing treatments in hydrogen ambient normally involve passivation of traps at thermal SiO2/Si interfaces by hydrogen. High-κ dielectric films are believed to exhibit significantly higher charge trapping affinity than SiO2. In this thesis, study of hydrogen trapping in alternate gate dielectric candidates such as HfO2 during annealing in hydrogen ambient is presented. Rutherford backscattering spectroscopy (RBS), elastic recoil detection analysis (ERDA) and nuclear reaction analysis (NRA) were used to characterize these thin dielectric materials. It was demonstrated that hydrogen trapping in bulk HfO2 is significantly reduced for pre-oxidized HfO2 prior to forming gas anneals. This strong dependence on oxygen pre-processing is believed to be due to oxygen vacancies/deficiencies and hydrogen-carbon impurity complexes that originate from organic precursors used in …
Date: August 2006
Creator: Ukirde, Vaishali
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Texas Cowboy as Myth: Visual Representations from the Late Twentieth Century

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The working cowboy remains part of the contemporary culture of Texas. A visual record of him appeared early in the state's history, in daguerreotypes, followed by representations in contemporary black and white as well as color photographs, film and video. Although the way of life for the Texas cowboy has changed, it remains a thriving part of the Texas economy, society, and culture. Moreover, the image of the cowboy has permeated popular culture and fine art. This paper explores what late twentieth century popular culture and fine art images of the cowboy signify, emphasizing aspects of how they signify in relation to an existing tradition of photographic representations. Using Barthes' "Myth Today," it considers how the documentary aspect of early photographic representations of cowboys is transformed in contemporary popular culture and fine art to become mythology, for example, by the exaggeration of features of dress to connote ideals allegorically.
Date: August 2006
Creator: Seaton, Melynda
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Genetic Modification of Fatty Acid Profiles in Cotton

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The industrial uses of cottonseed oil are limited by its fatty acid composition. Genetic modification of cotton lipid profiles using seed-specific promoters could allow cotton growers to produce valuable new oils in the seed without adverse effects on fiber quality and yield, therefore making this crop more commercially profitable. Transgenic cotton callus harboring a diverged fatty acid desaturase gene (FADX) from Momordica charantia was characterized for production of alpha-eleostearic acid (conjugated double bonds: 18:3 D9 cis, 11 trans, 13 trans), not normally found in cotton. Gas chromatography (GC) in conjunction with mass spectrometry (MS) confirmed production of alpha-eleostearic acid in the transgenic cotton tissues. A second series of transformation experiments introduced the cotton fatty acid thioesterase B (FATB) cDNA, fused to the seed-specific oleosin promoter into cotton to promote the over-expression of FATB, to generate cotton with increased palmitate in the cottonseed. PCR amplification, as well as fatty acid analysis by gas chromatography, confirmed introduction of the FATB cDNA in transgenic tissues. Collectively, these results demonstrate the feasibility of manipulating the fatty acid composition in cotton via transgenic approaches and form the basis for continued efforts to create novel oils in cottonseed.
Date: August 2005
Creator: Rommel, Amy A.
Object Type: Thesis or Dissertation
System: The UNT Digital Library

A Study of Breath Management as Treated by Four Major American Vocal Pedagogues: Appelman, Reid, Vennard, and Miller

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Trained musicians cannot use the same breath process in daily living as for singing. Also, the normal breath cycle applied to speech is not efficient. Therefore, students who are learning to sing need to know proper breathing techniques. In this thesis, I will describe the breathing process and the correct way to breathe while singing, based on studies of four American pedagogues; Appleman, Reid, Vennard and Miller. To understand the breathing process for singing, it is necessary to study and understand the anatomical system and the mechanics of the respiratory system. Therefore, the first chapter contains anatomical system of breath management. Then, in the second chapter, the specific breath management techniques of four American pedagogues will be examined and compared. Three of them, Appelman, Vennard, and Miller, suggested some exercises in order to develop correct and efficient breathing habits.
Date: August 2005
Creator: Kim, Jisuk
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Temperature tolerances and predation susceptibilities of transgenic and wildtype zebra danios, Danio rerio.

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Both the upper and lower temperature tolerances of red fluorescent protein transgenic zebra danios and wildtype zebra danios, Danio rerio, were significantly different via two different methods; however, all differences are small (< 1°C) and probably not ecologically important. The U.S. geographic distributions of both transgenic and wildtype zebra danios will not be restricted by their upper thermal tolerances, but will be limited to the southern and western portions of the U.S. by their lower thermal tolerances. Largemouth bass did not preferentially prey upon transgenic zebra danios compared to wildtype danios or wildtypes relative to a native fish. If transgenic or wildtype zebra danios are released into southern or western U.S. waters, it is possible they could be eliminated by predation.
Date: August 2005
Creator: Cortemeglia, Cheryl
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Voci Lontani for flute, trumpet, percussion, piano, and string quartet: Critical essay and score.

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This project consists of an original composition, Voci Lontani, and a critical essay about the composition. In this piece, the idea of musical simultaneity is explored. Therefore, the piece focuses on the idea of contrast: between measured rhythms and indeterminate rhythms, between tonality and atonality, and between musics in separate tempos. In order to explore the significance of musical simultaneity, four important compositional concepts-the simultaneous juxtaposition of different musics, polyrhythmic structure, controlled indeterminacy, and quotation-are discussed. Also, several examples of twentieth-century music that use these concepts are analyzed in the essay.
Date: August 2004
Creator: Goto, Yo
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Long-Term Impact of Mega-Sport Events on the Host Region

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The purpose of this paper is to analyze and identify the major factors that determine the success or failure of mega-sports events. The report begins with a discussion of why localities are willing to invest large sums of public monies in infrastructure and services to host these events. This is followed by a review of the methods used to assess the economic, fiscal, and social impacts of hosting large sporting events. It is observed that comprehensive analyses of the impacts of these events are not undertaken. Finally, the major factors that affect the success of these events are discussed along with suggestions for improving studies evaluating success or failure.
Date: August 2004
Creator: Shargorodsky, Paulo
Object Type: Thesis or Dissertation
System: The UNT Digital Library