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Computational Studies of Catalysis Mediated by Transition Metal Complexes

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Computational methods were employed to investigate catalytic processes. First, DFT calculations predicted the important geometry metrics of a copper–nitrene complex. MCSCF calculations supported the open-shell singlet state as the ground state of a monomeric copper nitrene, which was consistent with the diamagnetic character deduced from experimental observations. The calculations predicted an elusive terminal copper nitrene intermediate. Second, DFT methods were carried out to investigate the mechanism of C–F bond activation by a low-coordinate cobalt(I) complex. The computational models suggested that oxidative addition, which is very rare for 3d metals, was preferred. A π–adduct of PhF was predicted to be a plausible intermediate via calculations. Third, DFT calculations were performed to study ancillary ligand effects on C(sp3)–N bond forming reductive elimination from alkylpalladium(II) amido complexes with different phosphine supporting ligands. The dimerization study of alkylpalladium(II) amido complexes indicated an unique arrangement of dative and covalent Pd-N bonds within the core four-membered ring of bimetallic complexes. In conclusion, computational methods enrich the arsenal of methods available to study catalytic processes in conjunction with experiments.
Date: May 2019
Creator: Jiang, Quan
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Who is Who in Zimbabwe's Armed Revolution? Representation of the ZAPU/ZIPRA and the ZANU/ZANLA in High School History Textbooks Narratives of the Liberation War

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The liberation war was a watershed event in the history of Zimbabwe. According to the ZANU PF (Zimbabwe African National Union Patriotic Front) ruling elites, an understanding of the common experiences of the people during the liberation war provides the best opportunity to mold a common national identity and consciousness. However, the representation of important historical events in a nation's history is problematic. At best events are manipulated for political purposes by the ruling elites, and at the worst they are distorted or exaggerated. In Zimbabwe, the representation of the ZAPU/ZIPRA and the ZANU/ZANLA as liberation movements in high school history textbooks during the armed struggle is a hot potato. This study critically examined and explored the contested "representational practices" of the ZAPU/ZIPRA and the ZANU/ZANLA as liberation movements during the Zimbabwean armed revolution. By means of qualitative content analysis, seven high school history textbooks from Zimbabwe were analyzed. Drawing from postcolonial perspectives and insights, particularly Fanon's concept of the pitfall of national consciousness, the study unveiled the way in which Zimbabwean high school textbooks portrayed the ZAPU/ZIPRA and the ZANU/ZANLA as very different liberation movements whose roles and contributions were unequal. High school textbooks depicted the ZANU/ZANLA as a …
Date: May 2019
Creator: Sibanda, Lovemore
Object Type: Thesis or Dissertation
System: The UNT Digital Library

A Further Evaluation of Individual and Synthesized Contingencies within Functional Analysis Methods

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A functional analysis (FA) is the most commonly used assessment methodology for identifying maintaining variables influencing problem behavior. However, if an FA does not produce clear differentiation, researchers and practitioners often then modify procedures to include additional individualized variables. The interview-informed synthesized contingency analysis (IISCA) provides a marked departure from FA methodology and aims to include individualized factors at the initiation of the assessment in order to more rapidly produce differentiation and clear results. We sought to further evaluate and compare the outcomes of two different functional analysis methods: the single-contingency functional analysis (FA) and the interview-informed synthesized contingency analysis (IISCA) to determine the function of problem behavior and evaluate the subsequent function-based treatment determined from the functional analysis results with two children diagnosed with autism spectrum disorder (ASD). Both participants engaged in problem behavior maintained by single-contingencies of reinforcement identified within the single-contingency FA and emphasized by the effectiveness of each single-contingency function-based treatment.
Date: May 2019
Creator: Hendryx, Maggie
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Praseodymium Oxide and Organic Modified Cerium Oxide Nanoparticles for Electrodeposition of Nickel-Ceramic Nanocomposites to Enhance Corrosion Protection and Mechanical Properties

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There is a consistent need in many industries, especially oil and gas, to develop coatings which have higher corrosion resistance and better hardness to extend the lifetime of equipment when it is exposed to hostile environments. Electrodeposition has been a favorable method in the synthesis of metal coatings because of its low cost, convenience, ability to work at low temperatures, and ability to control surface morphology and structure. The inclusion of ceramic nanoparticles in metal matrix composites has previously been investigated as a technique to not only increase the corrosion resistance of the native metal but also to improve the hardness and mechanical properties. Cerium oxide nanoparticles were modified through the grafting of organic groups with increasing hydrophobicity for use in nickel coatings on stainless steel to further improve the corrosion properties while maintaining the hardness of the nanocomposite coatings. The process of modifying the cerium oxide nanoparticles involved the use of aryl diazonium salts and resulted in multilayers forming on the surface of the nanoparticles. Praseodymium oxide nanoparticles were also investigated as additives to nickel coatings, since praseodymium oxide has not yet been studied as a possible corrosion protection enhancement in coatings. These coatings were evaluated for composition and …
Date: May 2019
Creator: Sanders, Stephen
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Information Sharing and Storage Behavior via Cloud Computing: Security and Privacy in Research and Practice and Users' Trust

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This research contributes to the cloud computing (CC) literature and information science research by addressing the reality of information sharing and storage behavior (ISSB) of the users' personal information via CC. Gathering information about usage also allows this research to address the paradox between the research and practice. Additionally, this research explores the concept of trust and its role in the behavioral change relative to CC. The findings help reconcile the paradox between the two realms. Essay1 develops and tests cloud computing usage model (CCUM) that assesses ISSB. This model considers the main adoption determinants and the main drawbacks of CC. The study measures the main concerns of users found in the literature, perceived security and perceived privacy. The findings prove surprising on these concerns. Using multiple regression to analyze 129 valid survey responses, the results find that CC users are less concerned about the major issues of security and privacy and will use the technology based on peer usage. Essay 2 examines why users ignore the technology issues and elect to replace the traditional mechanisms for handling their personal information. The results of an interview-based study conducted on 11 normal users and 11 IT professionals clarify their perceptions about …
Date: May 2019
Creator: Al Smadi, Duha
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Modeling Marijuana Use Willingness and Problems as a Function of Social Rejection and Social Anxiety

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Marijuana is the second most commonly used substance in the US. A growing literature suggests that socially anxious individuals use marijuana to manage their symptoms in social situations, which may explain why they are also more likely to experience problems. Unfortunately, the majority of the literature is based on research conducted with adult samples or the co-occurrence of diagnoses in adolescent samples. The proposed study sought to test the link between social anxiety (SA) and proxies for ‘real-time' marijuana use behaviors (i.e., use willingness) as well as use-related problems among adolescents. Participants were 69 adolescents (15-17; 55% female) recruited from the community reporting any lifetime marijuana use. Participants were randomly assigned to a novel social rejection or neutral laboratory task and completed measures of SA, marijuana use frequency, and related problems. Consistent with adult findings, main effects of SA and experimental condition on marijuana use willingness were expected to be qualified by an interaction in which the greatest marijuana use willingness would occur among high SA youth post-rejection (H1), SA would be positively related to marijuana use problems (H2), and among adolescents in the rejection condition, marijuana use willingness would be positively correlated with use problems (H3). Only H2 was …
Date: May 2019
Creator: Cloutier, Renee
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Substrate Nanotopography and Stiffness Modulation of Cell Behavior

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The physical characteristics (i.e., nanostructure and stiffness) of the extracellular matrix where cells reside have been shown to profoundly affect numerous cellular events in vivo and also been employed to modulate cell behavior in vitro, yet how these physical cues regulate cell behavior is still elusive. Therefore, we engineered a variety of nanotopographies with different shapes and dimensions, and investigated how the nanotopographical cue, through focal adhesions-cytoskeleton-nucleus pathway, affected cell phenotype and function. We further designed and fabricated well-defined substrates which had either identical biochemical cue (adhesive ligand presentation) but different nanotopographical cues or identical nanotopography but different biochemical cues, and dissected the roles of these cues in cell modulation. In addition, we revealed that the human mesenchymal stem cells (hMSCs) could obtain nanotopographical memory from the past culture environment, and the nanotopographical memory influenced the future fate decision of the hMSCs. Moreover, we evaluated the effects of substrate nanotopographical and stiffness cues on the fibrogenesis of human lung fibroblasts in response to carbon nanotubes and highlighted the significance of these physical cues in the development of physiologically relevant in vitro models for nanotoxicological study. The mechanistic understanding of the physical regulation of cell behaviors will provide important insight into …
Date: May 2019
Creator: Wang, Kai
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Bio-Inspired Material Surfaces with Self-cleaning, Micromanipulation and Water Collection

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Geckos are famous for the skill of switchable adhesion that they use to stick on various surface while keep their fingers super clean. In the dissertation, a unique mechanism was discovered to explain gecko self-cleaning phenomena. Using atomic force microscopy (AFM), we managed to compare the microparticle-substrate adhesion and the microparticle-seta adhesion with a single seta bonded to the AFM cantilever. A dynamic effect was approved that high pulling-off speed could increase the microparticle-substrate adhesion and thus the self-cleaning appears at high moving speed. Based on the self-cleaning theory, a gecko-inspired N-doped graphene surface with switchable adhesion was achieved, which was designed into a bio-inspired micromanipulator with a success rate over 90%. When electrical bias was applied on this biomimetic surface, the charge concentration induced an electrical double layer (ELD) on the convex surfaces, which attracts polar water molecules to form a water bridge on it, significantly enhancing the adhesion on the wrinkled graphene surface, mimicking the capillary force on beetle feet. Therefore, the bio-inspired adhesive surface can be controlled with speed, electrical bias, humidity and different material surfaces. The water attraction phenomenon on the polarized surface was further tested for the potential application of water collection and evaporation in …
Date: May 2019
Creator: Wan, Yiyang
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Ensemble & Doctoral Reictal: 2019-11-12 -- UNT and Guyer High Choirs, Francis Vu (conducting)

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Choral concert performed at the UNT College of Music Winspear Hall, as well as recital presented in partial fulfillment of the Doctor of Musical Arts (DMA) degree for Francis Cathlina (conducting).
Date: November 12, 2019
Creator: University of North Texas. Concert Choir.
Object Type: Video
System: The UNT Digital Library

Ensemble Concert & Doctoral Recital: 2019-04-04 -- Men's Chorus and Women's Chorus

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Choir concert performed at the UNT College of Music Winspear Hall, as well as recital presented in partial fulfillment of the Doctor of Musical Arts (DMA) degrees for Joshua R. Brown and Charlotte Botha.
Date: April 4, 2019
Creator: University of North Texas. Men's Chorus.
Object Type: Video
System: The UNT Digital Library

Anacreon Who? How a Poem and a Tune Found Each Other to Make our National Anthem [Presentation]

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Presentation on the history of the Star Spangled Banner for the Denton (Benjamin Lyon) chapter of the Daughters of the American Revolution on September 6, 2019.
Date: September 6, 2019
Creator: Feustle, Maristella
Object Type: Presentation
System: The UNT Digital Library

Uncle Sam Does Not Want You: Military Rejection and Discharge during the World Wars

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In the United States, rapid military mobilization for the world wars marked a turning point in the national need to manage and evaluate manpower. To orchestrate manpower needs for the military, industry, and those relating to familial obligations, Woodrow Wilson's administration created the Selective Service System during the First World War. In categorizing men, local Selective Service boards utilized rapid physical and psychological diagnostic techniques and applied their assessments to current military branch induction standards to pronounce candidates as militarily fit or unfit. From World War I to World War II, the Selective Service System expanded as a bureaucracy but did not adequately address induction issues surrounding rapidly changing standards, racism, and inconsistent testing procedures. These persistent problems with Selective Service prevented the system from becoming truly consistent, fair, or effective. As a result of Selective Service System, War Department, and military branch standards, military rejection and prematurely military discharge rates increased in World War II. Additionally, though Selective Service did not accurately predict who would or would not serve effectively, rejected and prematurely discharged men faced harsh discrimination on the American home front during World War II.
Date: August 2019
Creator: Smith Chamberlain, Tiffany Leigh
Object Type: Thesis or Dissertation
System: The UNT Digital Library

A Pedagogical Guide to the Piccolo Trumpet

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The modern piccolo trumpet is required by professional trumpet players for the performance of solo repertoire, chamber music, orchestra, and wind band. Students in universities around the world study the piccolo trumpet in preparation for professional careers, but relatively few pedagogical tools exist to specifically focus on the nuanced techniques of the instrument such as articulation, range, and sound production. The purpose of this project is to create a pedagogical guide that can serve as a method for students learning the modern piccolo trumpet.
Date: May 2019
Creator: Goldman, Casey
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Allusions and Borrowings in Selected Works by Christopher Rouse: Interpreting Manner, Meaning, and Motive through a Narratological Lens

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Christopher Rouse (b. 1949), winner of the Pulitzer Prize for his Trombone Concerto (1993) and a Grammy award for his Concerto de Gaudi (1999), has come to the forefront as one of America's most prominent orchestral composers. Several of Rouse's works feature quotations of and strong allusions to other composers' works that are used both rhetorically and structurally. These borrowings range from a variety of different genres and styles of works, from Claudio Monteverdi's L'incoronazione di Poppea to Jay Ferguson's "Thunder Island." Due to the more accessible filtering and funneling methods of musical borrowings (proliferation of mass media), the weighty discourses attached to them, and their variety of functions (critiquing canons, engaging in an allusive tradition, etc.), quotation has become elevated to the most prominent of musical actors that trigger narrative listening strategies, which in turn have a stronger role in the formation of narratives about music as well as narratives of music. The primary aim of this study is to adapt and apply more recent methodological narrativity frameworks to selected instrumental compositions by Rouse containing quotations, suggesting that their manner of insertion, their method of disclosure, and their referential potential can benefit from being examined through various narrative lenses …
Date: May 2019
Creator: Morey, Michael J.
Object Type: Thesis or Dissertation
System: The UNT Digital Library

A Performance Edition of the Vespers Settings in Sacri E Festivi Concenti, Opera Nona by Giovanni Legrenzi

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Giovanni Legrenzi was a prolific composer of vocal music and maestro di cappella at the Basilica di San Marco but his vocal works are not often studied as a part of the Venetian lineage with composers such as Willaert, de Rore, Zarlino, Monteverdi, Cavalli, and Vivaldi. Despite his being a prolific composer who had significant influence on the work of other musicians in the traditional canon, references to Legrenzi in standard music publications (Grout, Taruskin, Grove Music Online, etc.) are at best sparse, and largely biographical. This dissertation is one step to correct that pattern by creating a performance edition of Sacri e festivi concenti, Opera nona, one of Legrenzi's significant works near the beginning of his Venetian period. This collection of sacred music was published on 12 June 1667 in Venice though Legrenzi's exact whereabouts at the time remain uncertain. This phase of his career can be defined by his having sought more prestigious and lucrative employment. Having lived and worked in rural Lombardy and Ferrara, he made unsuccessful overtures in places such as Milan, Bologna, Vienna, and Paris. A full score has been produced by transcribing from the part books of the Bologna Museo copy, which will allow …
Date: May 2019
Creator: Sullivan, Ryan W.
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Defining Components Linked to Bacterial Nutritional Utilization of Cyanide as a Sole Nitrogen Source

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One of the challenges in biology is placing a function on the myriad of gene sequences having become available from rapid advances in genome sequencing. One such example is a gene cluster (Nit1C) found in bacteria that is tied to the unusual ability of certain bacteria to grow when supplied cyanide as the sole nitrogen source. The term cyanotrophs has been applied to such bacteria, for which a genetic linkage between cyanotrophy and Nit1C was demonstrated for 10 separate bacteria. In addition to growth, cyanide induced the expression of Nit1C genes in all organisms tested, and in one case, deletion of one of the Nit1C genes (nitC) caused a loss of growth. Of the ten bacteria able to grow cyanotrophically, all gave evidence of harboring Nit1C on their genome except for two (Pseudomonas fluorescens Pf11764 and P. monteilii BCN3), which were sequenced and the presence of Nit1C was also confirmed. A broader search of bacteria identified 270 separate strains with the cluster, all limited to bacteria spanning the phyla Firmicutes, Actinobacteria, Proteobacteria and Cyanobacteria. Remarkably, many examples of a single representative of a given taxon contained Nit1C, most poignantly displayed by Pf11764 and PmBCN3; the interpretation being the cluster was …
Date: May 2019
Creator: Jones, Lauren Brittany
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Stephen Chatman's Piano Fantasies (1993): An Instructional and Performance Guide for Teachers and Intermediate Piano Students

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Contemporary repertoire is not commonly taught or explored by teachers during the intermediate level, when a student's musical training is transitioning to an advanced level. Nonetheless, it is important for piano instructors to be open-minded about contemporary music and have some perspective on the development of music repertoire in the future. The purpose of this dissertation is to provide a performance and pedagogical guide to Stephen Chatman's (b. 1950) Fantasies, from both technical and artistic viewpoints. The collection, which consists of eleven pieces, features a wide variety of contemporary idioms, styles, and means of notation. For instance, there are jazz-like syncopated rhythms, asymmetrical accents reminiscent of Primitivism, and Impressionistic or dissonant sonorities. Fantasies is not only a valuable tool for students to explore new sounds and improve their performing techniques while executing nontraditional notations and contemporary idioms, it is also a great teaching resource for instructors to promote students' musicality through hearing, seeing, and thinking. In this study, I provide individual, detailed descriptions for each of the pieces in the score, adding examples on how to address the difficulties they present to the performer. As a result, instructors can better understand how to help students prepare to perform this collection …
Date: May 2019
Creator: Li, Hanhan
Object Type: Thesis or Dissertation
System: The UNT Digital Library

The Impact of Sociocultural and Information Communication Technology Adoption Factors on the Everyday Life Information Seeking Behavior of Saudi Students in the United States

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This study analyzes the sociocultural factors that affect Saudi students in the U.S. as they seek information and explores to what extent these factors impact their everyday life information seeking (ELIS) behavior and their information technology behavior (ITB). The factors in this study illustrate the unique sociocultural values that distinguish Saudi students from other international student groups: gender segregation, emphasis on religion, social support, and utilization of the consultation concept. After collecting data from an online survey, the data from linear regression analyses revealed that only one culture factor (the language barrier) showed a significant impact on Saudi student ELIS in the U.S., while the other factors were not statistically significant. Also, the findings indicated that perceived usefulness (PU) and perceived ease of use (PEU) were statistically significant to the ELIS of Saudi students. Furthermore, the study showed that after academic information, food and drink, entertainment, and health were the top student needs, the top ranking sources for everyday life seeking information were social media and the Internet. The findings of the study help to shed light on a sizable user group. As the fourth largest group of international students in the U.S., Saudi students have been underrepresented in research. …
Date: May 2019
Creator: Alkahtani, Latifah M
Object Type: Thesis or Dissertation
System: The UNT Digital Library

An Investigation of Multiple Articulation as Applied to Saxophone Literature and Its Performance: An Historical and Pedagogical Approach

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Multiple articulation is a technique that is becoming commonplace in the saxophone literature. This study provides a detailed explanation of how produce the technique. Its application to saxophone literature is explored with musical examples and commentary by the author. A compilation of pedagogical viewpoints regarding multiple articulation from educators spanning the last century is provided.
Date: May 2019
Creator: Reséndez, Joey (José Luís)
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Analogous Views (Green)

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Work of art of Inkjet Print by artist Chris Wright Evans, as part of a 2020 MFA Exhibition, entitled "Brachaid". Custom Painted Frame
Date: 2019
Creator: Evans, Chris Wright
Object Type: Artwork
System: The UNT Digital Library

Heller's Soldier in White

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Work of art of Inkjet Print by artist Chris Wright Evans, as part of a 2020 MFA Exhibition, entitled "Brachaid".
Date: 2019
Creator: Evans, Chris Wright
Object Type: Artwork
System: The UNT Digital Library

River Sticks

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Work of art of Inkjet Print by artist Chris Wright Evans, as part of a 2020 MFA Exhibition, entitled "Brachaid".
Date: 2019
Creator: Evans, Chris Wright
Object Type: Artwork
System: The UNT Digital Library

Sensible Horizon

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Work of art of Inkjet Print by artist Chris Wright Evans, as part of a 2020 MFA Exhibition, entitled "Brachaid".
Date: 2019
Creator: Evans, Chris Wright
Object Type: Artwork
System: The UNT Digital Library

Revealed to Misdirect

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Work of art of Inkjet Print by artist Chris Wright Evans, as part of a 2020 MFA Exhibition, entitled "Brachaid".
Date: 2019
Creator: Evans, Chris Wright
Object Type: Artwork
System: The UNT Digital Library