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Tribological Improvements of Carbon-Carbon Composites by Infiltration of Atomic Layer Deposited Lubricious Nanostructured Ceramic Oxides (open access)

Tribological Improvements of Carbon-Carbon Composites by Infiltration of Atomic Layer Deposited Lubricious Nanostructured Ceramic Oxides

A number of investigators have reported enhancement in oxidation and wear resistant of carbon-carbon composites (CCC) in the presence of protective coating layers. However, application of a surface and subsurface coating system that can preserve its oxidation and wear resistance along with maintaining lubricity at high temperature remains unsolved. To this end, thermodynamically stable protective oxides (ZnO/Al2O3/ZrO2) have been deposited by atomic layer deposition (ALD) to infiltrate porous CCC and graphite foams in order to improve the thermal stability and wear resistance in low and high speed sliding contacts. Characterization of microstructural evolution was achieved by using energy dispersive x-ray spectroscopy (EDS) mapping in scanning electron microscope (SEM) coupled with focused ion beam (FIB), x-ray tomography, high resolution transmission electron microscopy (HRTEM), scanning transmission electron microscopy (STEM) and X-ray diffraction (XRD). Evaluation of the tribological properties of CCC coated with abovementioned ALD thin films were performed by employing low speed pure sliding tribometer and a high speed/frequency reciprocating rig to simulate the fretting wear behavior at ambient temperature and elevated temperatures of 400°C.It was determined with x-ray tomography imaging and EDS mapping that ALD ZnO/Al2O3/ZrO2 nanolaminates and baseline ZrO2 coatings exhibited excellent conformality and pore-filling capabilities down to ~100 μm …
Date: August 2011
Creator: Mohseni, Hamidreza
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Modeling Transition Metal Chemistry for Catalytic Functionalization of Molecules (open access)

Modeling Transition Metal Chemistry for Catalytic Functionalization of Molecules

The diversity of transition metal complexes allows for a wide range of chemical processes to be mediated by the metal, from catalysis to surface chemistry. Investigations into the structure and electronic configuration of transition metal complexes allow for tuning of desired species by modifications to the ligands and/or metals to achieve more efficient thermodynamics and kinetics for the process of interest. Transition metals, often used in catalysts for a number of important processes, require detailed descriptions of intermediates, transition states and products to fully characterize a reaction mechanism(s) in order to design more active and efficient catalysts. Computational investigations into inorganic catalysts are explored with the aim of understanding the activity of each species and how modifications of supporting ligands, co-ligands and metals vary the interaction along the reaction pathway. Reported results give important insight into the development of the most active complexes in addition to determining the least active complexes to aid experimental development. This report first investigates the mechanisms of two unique transfer reactions: 1) formation of low coordinate nickel-nitrene ((P~P)Ni=NR; P~P = 1,2-bis(dihydrophosphino)-ethane or 1,2-bis(difluoromethylphosphino)-ethane) complexes as catalysts for nitrogen atom transfer and 2) oxidation of a triphosphorus niobium complex, [(η2-P3SnPh3)Nb(OMe)3], for the transfer of the phosphorus …
Date: August 2011
Creator: Morello, Glenn
Object Type: Thesis or Dissertation
System: The UNT Digital Library
A Pedagogical and Analytical Study of Dušan Bogdanović’s Polyrhythmic and Polymetric Studies for Guitar (open access)

A Pedagogical and Analytical Study of Dušan Bogdanović’s Polyrhythmic and Polymetric Studies for Guitar

Polymeter has been a relatively unexplored compositional technique of music of the Common Practice Period. Dušan Bogdanović’s Polyrhythmic and Polymetric Studies for Guitar is recognized in the guitar world as not only an important theoretical treatise, but also a benchmark for more advanced levels of improvisation. Currently, his treatise remains the best source for learning polymetric improvisation on the guitar. My personal contribution stems from the idea that multiple interpretations of thought processes and technical approaches are possible when learning to play polymeters on the guitar. The first section focuses on providing an alternative technical approach towards learning to play polymeters on the guitar by simplifying selected exercises in Bogdanović’s treatise from their original presentation, and demonstrating further possibilities as to how the exercises can be applied in a practical manner to improvisation. The second part reveals through analysis of the Concert Studies 1, 2, and 5 both his innovative improvisatory use of polymeter as a stylistic device, and his ties to traditional ideas of structure.
Date: May 2011
Creator: Morey, Michael J.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Correlates of Post-Traumatic Stress Disorder and Disorder of Extreme Stress Not Otherwise Specified among Palestinian Child Ex-Detainees (open access)

Correlates of Post-Traumatic Stress Disorder and Disorder of Extreme Stress Not Otherwise Specified among Palestinian Child Ex-Detainees

The objective of this study is to investigate the variations in the type of trauma (post-traumatic stress disorder (PTSD) and disorder of extreme stress not otherwise specified (DESNOS) resulting first from group membership, and second from variations in socioeconomic status, and last, from exposure to physical and psychological methods of interrogation due to imprisonment. I use a diverse sample of 202 child ex-detainees who served sentences in Israeli prisons and were 17 years of age or less at the time of arrest. Various regression techniques were utilized to determine the most parsimonious way to distinguish between the three groups in their trauma responses. The key finding in this study is that child refugee ex-detainees living in refugee camps, in general, did not report PTSD or DESNOS reactions compared to their counterparts. Continuing PTSD and DESNOS symptoms were more prevalent among the group of refugees living outside the camps. However, there is at least one finding that supported what I hypothesized: refugees living in camps were more likely to experience elevated levels of alterations in attention or consciousness (DESNOS2). For refugees in camps, the DESNOS absence tells us that the volatile childhood these children experienced was not associated with severe pathological …
Date: August 2011
Creator: Nabhan, Inshirah Nimer
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Evaluating the Effectiveness of a Parent training Protocol Based on an Acceptance and Commitment Therapy Philosophy of Parenting (open access)

Evaluating the Effectiveness of a Parent training Protocol Based on an Acceptance and Commitment Therapy Philosophy of Parenting

Thirty-four parents were referred by their CPS caseworkers to participate in one of two ACT for Parenting workshops. These workshops followed a 12 hour treatment protocol based on an acceptance and commitment therapy philosophy of parenting. Briefly, an ACT philosophy of parenting maintains that effective parenting requires awareness and acceptance of thoughts and feelings as they occur in the context of the parent-child relationship. An ACT philosophy of parenting also relies heavily on the identification and commitment to parenting values. Participants were asked to track acceptance and valuing behavior on a daily basis for 25 days prior to the intervention and 25 days post-intervention, as well as to complete a package of self-report instruments designed to measure both ACT specific and general psychological processes, at three different points (pre-, post- and follow-up). Nineteen parents received the treatment, and of those, seventeen provided follow-up data 3-4 months post-intervention. Results indicate statistically significant changes in the expected directions for scores on the BASC-2 Externalizing Composite as well as on the Meta-Valuing Measure. A total of 10 parents also evidenced clinically significant change in the expected directions on a variety of outcome measures.
Date: August 2011
Creator: O'Brien, Karen M.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Does Prostate Cancer Begin in the Prostate? Key Predictors of Diagnosis (open access)

Does Prostate Cancer Begin in the Prostate? Key Predictors of Diagnosis

The purpose of this exploratory study was to identify the key predictors of prostate cancer; such study may lead to the development of appropriate interventions and prevention. Previous epidemiological studies have found these following factors to be key predictors for being diagnosed with hormone-associated carcinoma such as prostate cancer: age, ethnicity, physical activity, family history, diet, sleep amount, marital status, and having another form of carcinoma. Many studies have included results only for men over the age of 65, however, prostate cancer is claiming the lives of many African American, Hispanic and White American men over the age of 35, and younger men are more likely to battle it if they are genetically predisposed. The sample population (N =21,646) was selected because men aged 35 or over have the highest prevalence of prostate cancer. Of this sample, 619 reported having prostate cancer, and 1,401 reported having some other type of cancer. This study employs a logistic regression model using SAS® and utilizes the National Health Interview Survey data set and a multivariate analysis of the years 2006, 2007, and 2008. To improve the quality of future research the methods need modification, the subpopulation being studied should be larger, and the …
Date: August 2011
Creator: Orakpo, W. Nnamdi
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Parent Involvement and Science Achievement: A Latent Growth Curve Analysis (open access)

Parent Involvement and Science Achievement: A Latent Growth Curve Analysis

This study examined science achievement growth across elementary and middle school and parent school involvement using the Early Childhood Longitudinal Study – Kindergarten Class of 1998 – 1999 (ECLS-K). The ECLS-K is a nationally representative kindergarten cohort of students from public and private schools who attended full-day or half-day kindergarten class in 1998 – 1999. The present study’s sample (N = 8,070) was based on students that had a sampling weight available from the public-use data file. Students were assessed in science achievement at third, fifth, and eighth grades and parents of the students were surveyed at the same time points. Analyses using latent growth curve modeling with time invariant and varying covariates in an SEM framework revealed a positive relationship between science achievement and parent involvement at eighth grade. Furthermore, there were gender and racial/ethnic differences in parents’ school involvement as a predictor of science achievement. Findings indicated that students with lower initial science achievement scores had a faster rate of growth across time. The achievement gap between low and high achievers in earth, space and life sciences lessened from elementary to middle school. Parents’ involvement with school usually tapers off after elementary school, but due to parent school …
Date: August 2011
Creator: Johnson, Ursula Yvette
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Electrical and Structure Properties of High-κ Barium Tantalite and Aluminum Oxide Interface with Zinc Oxide for Applications in Transparent Thin Film Transistors (open access)

Electrical and Structure Properties of High-κ Barium Tantalite and Aluminum Oxide Interface with Zinc Oxide for Applications in Transparent Thin Film Transistors

ZnO has generated interest for flexible electronics/optoelectronic applications including transparent thin film transistors (TFTs). For this application, low temperature processes that simultaneously yield good electrical conductivity and optical transparency and that are compatible with flexible substrates such as plastic, are of paramount significance. Further, gate oxides are a critical component of TFTs, and must exhibit low leakage currents and self-healing breakdown in order to ensure optimal TFTs switching performance and reliability. Thus, the objective of this work was twofold: (1) develop an understanding of the processing-structure-property relationships of ZnO and high-κ BaTa2O6 and Al2O3 (2) understand the electronic defect structure of BaTa2O6 /ZnO and Al2O3/ZnO interfaces and develop insight to how such interfaces may impact the switching characteristics (speed and switching power) of TFTs featuring these materials. Of the ZnO films grown by atomic layer deposition (ALD), pulsed laser deposition (PLD) and magnetron sputtering at 100-200 °C, the latter method exhibited the best combination of n-type electrical conductivity and optical transparency. These determinations were made using a combination of photoluminescence, photoluminescence excitation, absorption edge and Hall measurements. Metal-insulator-semiconductor devices were then fabricated with sputtered ZnO and high-κ BaTa2O6 and Al2O3 and the interfaces of high-κ BaTa2O6 and Al2O3 with ZnO …
Date: August 2011
Creator: Kuo, Fang-Ling
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Ancient Musical Ideas Through a Twenty-First Century Lens: An Examination of Tarik O’Regan’s Scattered Rhymes and Its Relationship to Guillaume de Machaut’s Messe de Notre Dame (open access)

Ancient Musical Ideas Through a Twenty-First Century Lens: An Examination of Tarik O’Regan’s Scattered Rhymes and Its Relationship to Guillaume de Machaut’s Messe de Notre Dame

British composer Tarik Hamilton O’Regan (b. 1978, London) is earning a reputation as an important composer of today. The innovative works of O’Regan are entering the spectrum of professional, educational, and community performing organizations across the United States and Europe. Scattered Rhymes’ intricate melodic, harmonic, and rhythmic relationships with Messe de Notre Dame by Guillaume de Machaut (c.1300-1377) make an examination and comparison of the two works significant. Analyzing Scattered Rhymes by tracing its roots to Guillaume de Machaut’s Messe de Notre Dame, results in a renewed interest in this ancient work and brings prominence to Tarik O’Regan’s modern musical interpretation of ancient ideas. Understanding Scattered Rhymes as a work based on ideas from the fourteenth century in fusion with compositional concepts rooted in the modern era promotes Scattered Rhymes as one that is valuable in the current musical landscape.
Date: August 2011
Creator: LaBarr, Cameron Frederick
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Intimate Partner Violence Among Female Undergraduates: The Role of Language in the Development of Posttraumatic Stress (open access)

Intimate Partner Violence Among Female Undergraduates: The Role of Language in the Development of Posttraumatic Stress

Research findings across a variety of samples (e.g., clinical, shelter, hospital) estimate that 31% to 84% of women who have experienced intimate partner violence (IPV) exhibit symptoms of posttraumatic stress disorder (PTSD). The current study sought to further investigate the abuse-trauma link by examining the relationship between lifetime trauma exposure, type of abuse (i.e., physical, psychological), and perspective-taking abilities (i.e., here-there, now-then). The role of experiential avoidance in the development of PTSD symptoms was also examined. Results indicated that lifetime trauma exposure (β = .31) and psychological abuse (β = .34) were significant predictors of PTSD symptomatology. Additionally, analyses revealed that experiential avoidance (β = .65) was a significant predictor of PTSD symptoms that partially mediated the relationship between IPV and PTSD symptomatology. Implications of findings are discussed as well as future suggestions for research examining type of IPV and PTSD.
Date: August 2011
Creator: Larson, Christina Mary
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Nanoscale Materials Applications: Thermoelectrical, Biological, and Optical Applications with Nanomanipulation Technology (open access)

Nanoscale Materials Applications: Thermoelectrical, Biological, and Optical Applications with Nanomanipulation Technology

In a sub-wavelength scale, even approaching to the atomic scale, nanoscale physics shows various novel phenomena. Since it has been named, nanoscience and nanotechnology has been employed to explore and exploit this small scale world. For example, with various functionalized features, nanowire (NW) has been making its leading position in the researches of physics, chemistry, biology, and engineering as a miniaturized building block. Its individual characteristic shows superior and unique features compared with its bulk counterpart. As one part of these research efforts and progresses, and with a part of the fulfillment of degree study, novel methodologies and device structures in nanoscale were devised and developed to show the abilities of high performing thermoelectrical, biological, and optical applications. A single β-SiC NW was characterized for its thermoelectric properties (thermal conductivity, Seebeck coefficient, and figure of merit) to compare with its bulk counterpart. The combined structure of Ag NW and ND was made to exhibit its ability of clear imaging of a fluorescent cell. And a plasmonic nanosture of silver (Ag) nanodot array and a β-SiC NW was fabricated to show a high efficient light harvesting device that allows us to make a better efficient solar cell. Novel nanomanipulation techniques were …
Date: August 2011
Creator: Lee, Kyung-Min
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Personnel Preparation in Special Education: An Exploration of Autism Spectrum Disorders Programmatic Changes in Institutions of Higher Education Teacher Training Programs (open access)

Personnel Preparation in Special Education: An Exploration of Autism Spectrum Disorders Programmatic Changes in Institutions of Higher Education Teacher Training Programs

Programmatic change related to autism spectrum disorders (ASD) training in special education teacher education programs across the U.S. and institutional variables that influenced change were examined. Variables included institutions’ current coverage of autism content in coursework and institution enrollment. One faculty member from each identified institution was invited to participate in the study. Data were collected from 136 special education faculty using an exploratory survey instrument, the National Survey on ASD Preparation in Undergraduate Special Education Teacher Training Programs (NSAP). This study was designed around themes which emerged from empirical and pragmatic research findings conceptualizing prevalent issues in personnel preparation for ASD including critical knowledge and skills needed by teachers to effectively serve students with ASD. Results indicated a significant number of programmatic changes (66%) remain to be implemented in undergraduate special education programs at institutions participating in the study.
Date: August 2011
Creator: Lett-Stallworth, Tawana
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Image Representation and Interactivity: An Exploration of Utility Values, Information-Needs and Image Interactivity (open access)

Image Representation and Interactivity: An Exploration of Utility Values, Information-Needs and Image Interactivity

This study was designed to explore the relationships between users and interactive images. Three factors were identified and provided different perspectives on how users interact with images: image utility, information-need, and images with varying levels of interactivity. The study used a mixed methodology to gain a more comprehensive understanding about the selected factors. An image survey was used to introduce the participants to the images and recorded utility values when given a specific task. The interviews allowed participants to provide details about their experiences with the interactive images and how it affected their utility values. Findings from the study showed that images offering the highest level of interactivity do not always generate the highest utility. Factors such as personal preference, specifically speed and control of the image, affect the usefulness of the image. Participant also provided a variety of uses where access to interactive images would be beneficial. Educational settings and research tools are a few examples of uses provided by participants.
Date: August 2011
Creator: Lewis, Elise C.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Genetic Analysis of Development and Behavior in Hypoxia and Cellular Characterization of Anoxia Induced Meiotic Prophase Arrest in Caenorhabditis Elegans (open access)

Genetic Analysis of Development and Behavior in Hypoxia and Cellular Characterization of Anoxia Induced Meiotic Prophase Arrest in Caenorhabditis Elegans

It was hypothesized that chronic hypoxia will affect various biological processes including developmental trajectory and behavior. To test this hypothesis, embryos were raised to adulthood in severe hypoxic environments (0.5% O2 or 1% O2, 22°C) and analyzed for survival rate, developmental progression, and altered behaviors. Wildtype hermaphrodites survive chronic hypoxia yet developmental trajectory is slowed. The hermaphrodites raised in chronic hypoxia had different phenotypes in comparison to the normoxic controls. First, hermaphrodites exposed to chronic hypoxia produced a significantly lower number of embryos and had a slight increase in male progeny. This suggests that chronic hypoxia exposure during development affects the germline. Second, animals raised in chronic hypoxia from embryos to young adults have a slight increase in lifespan when re-exposed to a normoxic environment, indicating that chronic hypoxia does not negatively decrease lifespan. Finally, hermaphrodites that were raised in hypoxia will lay the majority of their eggs on the area of the agar plate where the bacterial lawn is not present. This is in contrast to animals in normoxia, which lay the majority of their eggs on the bacterial lawn. One hypothesis for this hypoxia-induced egg-laying behavior is that the animal can sense microenvironments in hypoxia. To examine if …
Date: August 2011
Creator: Little, Brent Ashley
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Molecular Basis of Plant Defense Against Aphids: Role of the Arabidopsis Thaliana PAD4 and MPL1 Genes (open access)

Molecular Basis of Plant Defense Against Aphids: Role of the Arabidopsis Thaliana PAD4 and MPL1 Genes

Myzus persicae (Sülzer), commonly known as green peach aphid (GPA), utilizes its slender stylet to penetrate the plant tissues intercellularly and consume copious amounts of photoassimilates present in the phloem sap causing extensive damage to host plants. The compatible interaction between GPA and Arabidopsis thaliana enabled us to characterize plant response to aphid infestation. Upon GPA infestation, Arabidopsis PAD4 (PHYTOALEXIN DEFICIENT4) gene modulates premature leaf senescence, which is involved in the programmed degradation of cellular components and the export of nutrients out of the senescing leaf. Senescence mechanism is utilized by plants to limit aphid growth. In addition, PAD4 provides antixenosis (deters insect settling and feeding) and antibiosis (impair aphid fecundity) against GPA and adversely impact sieve element availability to GPA. Basal expression of PAD4 contributes to antibiosis, and the GPA-induced expression of PAD4 contributes to antixenosis. Mutation in the Arabidopsis stearoyl-ACP desaturase encoding SSI2 (suppressor of SALICYLIC ACID [SA] insensitivity2) gene that results in an accelerated cell death phenotype and dwarfing, also conferred heightened antibiosis to GPA. Results of this study indicate that PAD4 is required for the ssi2-mediated enhanced antibiosis to GPA. The PAD4 protein contains conserved Ser, Asp and His residues that form the catalytic triad of …
Date: August 2011
Creator: Louis, Joe
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Biocompatible Hybrid Nanomaterials Involving Polymers and Hydrogels Interfaced with Phosphorescent Complexes and Toxin-Free Metallic Nanoparticles for Biomedical Applications (open access)

Biocompatible Hybrid Nanomaterials Involving Polymers and Hydrogels Interfaced with Phosphorescent Complexes and Toxin-Free Metallic Nanoparticles for Biomedical Applications

The major topics discussed are all relevant to interfacing brightly phosphorescent and non-luminescent coinage metal complexes of [Ag(I) and Au(I)] with biopolymers and thermoresponsive gels for making hybrid nanomaterials with an explanation on syntheses, characterization and their significance in biomedical fields. Experimental results and ongoing work on determining outreaching consequences of these hybrid nanomaterials for various biomedical applications like cancer therapy, bio-imaging and antibacterial abilities are described. In vitro and in vivo studies have been performed on majority of the discussed hybrid nanomaterials and determined that the cytotoxicity or antibacterial activity are comparatively superior when compared to analogues in literature. Consequential differences are noticed in photoluminescence enhancement from hybrid phosphorescent hydrogels, phosphorescent complex ability to physically crosslink, Au(I) sulfides tendency to form NIR (near-infrared) absorbing AuNPs compared to any similar work in literature. Syntheses of these hybrid nanomaterials has been thoroughly investigated and it is determined that either metallic nanoparticles syntheses or syntheses of phosphorescent hydrogels can be carried in single step without involving any hazardous reducing agents or crosslinkers or stabilizers that are commonly employed during multiple step syntheses protocols for syntheses of similar materials in literature. These astounding results that have been discovered within studies of hybrid nanomaterials …
Date: August 2011
Creator: Marpu, Sreekar B.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Redacted Dominionism: An Evangelical, Environmentally Sympathetic Reading of the Early Genesis Narrative (open access)

Redacted Dominionism: An Evangelical, Environmentally Sympathetic Reading of the Early Genesis Narrative

Critiques of the environmental ramifications of the early Genesis narrative by environmental thinkers such as Aldo Leopold, Ian McHarg, and Lynn White underscore a longstanding tension between the environmental movement and Western Christianity. The evangelical community (EC) especially, has been at odds with the environmental movement, as the EC grounds its theology regarding human relations to nature on the Genesis narrative—and especially the Genesis 1:26-28 dominion mandate— interpreted with a literal hermeneutic. The EC generally concludes in favor of either a dominionist interpretation, that mankind has dominion over nature, or a stewardship interpretation, that mankind’s dominion is more akin to tending or stewarding than to domination. Both interpretations trend toward the anthropocentrism that Leopold, McHarg, and White criticize. J. Baird Callicott postulates a third, less anthropocentric view: the citizenship interpretation, that humanity is co-citizen with nonhuman beings, rather than a superior. Callicott’s view, while commendable on key points, is incompatible with EC methodology because it is grounded only on Genesis 2 and subsequent passages, rejecting the legitimacy of Genesis 1:26-28 altogether. A fourth interpretation is proposed here, redacted dominionism, derived using EC methodology, and claiming that human relations to nature are based on theocentric themes. Redacted dominionism understands humanity as …
Date: August 2011
Creator: Cone, Christopher
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Design and Development of Soft Landing Ion Mobility: A Novel Instrument for Preparative Material Development (open access)

Design and Development of Soft Landing Ion Mobility: A Novel Instrument for Preparative Material Development

The design and fabrication of a novel soft landing instrument Soft Landing Ion Mobility (SLIM) is described here. Topics covered include history of soft landing, gas phase mobility theory, the design and fabrication of SLIM, as well as applications pertaining to soft landing. Principle applications devised for this instrument involved the gas phase separation and selection of an ionized component from a multicomponent gas phase mixture as combing technique to optimize coatings, catalyst, and a variety of alternative application in the sciences.
Date: August 2011
Creator: Davila, Stephen Juan
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Photophysics and Photochemistry of Copper(I) Phosphine and Collidine Complexes: An Experimental/Theoretical Investigation (open access)

Photophysics and Photochemistry of Copper(I) Phosphine and Collidine Complexes: An Experimental/Theoretical Investigation

Copper(I) complexes have been studied through both experimental and computational means in the presented work. Overall, the work focuses on photophysical and photochemical properties of copper(I) complexes. Photophysical and photochemical properties are found to be dependent on the geometries of the copper(I) complexes. One of the geometric properties that are important for both photochemical and photophysical properties is coordination number. Coordination numbers have been observed to be dependent on both ligand size and recrystallization conditions. The complexes geometric structure, as well as the electronic effects of the coordination ligands, is shown both computationally as well as experimentally to affect the emission energies. Two-coordinate complexes are seen to have only weak emission at liquid nitrogen temperature (77 K), while at room temperature (298 K) the two-coordinate complexes are not observed to be luminescent. Three-coordinate complexes are observed to be luminescent at liquid nitrogen temperature as well as at room temperature. The three-coordinate complexes have a Y-shaped ground (S0) state that distorts towards a T-shape upon photoexcitation to the lowest lying phosphorescent state (T1). The geometric distortion is tunable by size of the coordinating ligand. Luminescence is controllable by limiting the amount of non-radiative emission. One manner by which non-radiative emission is …
Date: August 2011
Creator: Determan, John J.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Strong Choquet Topologies on the Closed Linear Subspaces of Banach Spaces (open access)

Strong Choquet Topologies on the Closed Linear Subspaces of Banach Spaces

In the study of Banach spaces, the development of some key properties require studying topologies on the collection of closed convex subsets of the space. The subcollection of closed linear subspaces is studied under the relative slice topology, as well as a class of topologies similar thereto. It is shown that the collection of closed linear subspaces under the slice topology is homeomorphic to the collection of their respective intersections with the closed unit ball, under the natural mapping. It is further shown that this collection under any topology in the aforementioned class of similar topologies is a strong Choquet space. Finally, a collection of category results are developed since strong Choquet spaces are also Baire spaces.
Date: August 2011
Creator: Farmer, Matthew Ray
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Are Alzheimer's Special Care Units Really Special? Effects of Residential Status on Family Members' Perspectives on High Quality Care for their Loved-Ones in Long-Term Care (open access)

Are Alzheimer's Special Care Units Really Special? Effects of Residential Status on Family Members' Perspectives on High Quality Care for their Loved-Ones in Long-Term Care

This analysis of secondary data collected from family members of nursing home residents in North Texas (n = 422) used a mixed methods approach to determine if there is a difference in perspectives on quality care among family members of Alzheimer’s/Dementia Special Care Unit (ADSCU) residents compared to those of non-ADSCU residents. Descriptive content analysis was used identify and condense responses to an open-ended question into four meaningful categories of qualities of care. An independent t-test was employed to determine if there was a difference between family members of ADSCU residents and family members of non-ADSCU residents regarding their rating of their loved-ones’ nursing home on the important qualities of care they identified from the open-ended question. Closed-ended questions were organized into indices of these qualities of care, and ordinary least square regression was employed to determine if there were significant differences between perceptions of family members of ADSCU residents and those of non-ADSCU residents regarding care their loved-ones are receiving on these qualities of care, controlling for frequency of visit.
Date: August 2011
Creator: Fawcett, Elizabeth Jean
Object Type: Thesis or Dissertation
System: The UNT Digital Library
The Parent-Initiated Task Motivational Climate and Factors Influencing Eighth Grade Boys’ Intention to Continue Sports (open access)

The Parent-Initiated Task Motivational Climate and Factors Influencing Eighth Grade Boys’ Intention to Continue Sports

The motivational climate, as defined by parents’ behaviors, and athletes’ goal orientations are essential in understanding children’s experiences with sport. The purpose of this study was to examine the perceived motivational climate created by parents, and its relationship to psychological outcomes experienced by adolescent male athletes in youth sports. In particular, the parent created task climate was examined through its influence on goal orientation and subsequently to psychological outcomes experienced in sport, specifically, sport competence, self-esteem, enjoyment, and intention to continue participating in sport. Participants were 405 8th grade male athletes (mean age = 13.5); (Sample A: n = 205; Sample B: n = 200). As expected, the task-oriented parent initiated motivational climate was associated with the boys’ mastery goal orientation. Participants with higher mastery goal orientation had greater sport competence, self-esteem, and more enjoyment in sport. Intention to continue playing sport was predicted primarily by their level of enjoyment, and secondarily by their increased feelings of self-esteem.
Date: August 2011
Creator: Force, Erica C.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Risk and Resilience Faced by Children of Deployed Service Members (open access)

Risk and Resilience Faced by Children of Deployed Service Members

The purpose of this study was to examine the impact of military deployment on children, and the roles that risk and protective factors and parenting stress play in emotional symptoms and behaviors exhibited by children while their parents are deployed. A sample of 143 parents (recruited from all branches of the military) who remained at home while their spouses were deployed completed online self-report questionnaires measuring demographic and background information, child internalizing and externalizing behavior, parenting stress, child adaptability, valuing behavior, family cohesion/environment, and parenting behaviors. The sample primarily consisted of mothers (n = 141) and Caucasian individuals (n = 126), which may limit the generalizability of the findings. Results of the study suggest risk factors including parenting stress, corporal punishment, length of time a parent is deployed, and type of deployment (combat vs. non-combat) were predictive of poorer child outcomes. Protective factors including values consistent behavior, child adaptability, and family cohesion were predictive of better childhood outcomes. Parenting stress served as a mediating variable between the relationship of total risk and child outcomes, while values consistent behavior served as a mediating variable between the relationship of protective factors experienced by children and child outcomes. Military deployments not only impact …
Date: August 2011
Creator: Geddes, Jeffrey D.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Combat Near-Death Experiences: An Exploratory, Mixed-Methods Study (open access)

Combat Near-Death Experiences: An Exploratory, Mixed-Methods Study

This mixed-methods study’s purpose was a systematic comparison of contents and aftereffects of near-death experiences (NDEs) occurring in a variety of circumstances with those occurring in combat. They completed an online survey: a demographic questionnaire, the Near-Death Experience Scale, the Life Changes Inventory-Revised (LCI-R), and four narrative response items. Survey completers were 68 participants: 20 combat near-death experiencers (cNDErs) and 48 non-NDErs (nNDErs). The 29% of participants who met NDE Scale criterion for an NDE was comparable to NDE incidence findings from previous retrospective studies. For statistical analyses, significance was set at p < .05, and effect size (Cohen’s d) was calculated. Mean total NDE Scale scores were significantly lower for cNDErs than variety-of-circumstance NDErs from one of two comparable studies (t = 5.083, p < .0001, d = -1.26), possibly suggesting cNDEs may have “less depth” than other-variety NDEs. Regarding cNDE aftereffects, absence of previous LCI-R data made comparison impossible. Cronbach’s alpha analysis yielded acceptable reliability on the total scale and seven of nine subscales, a finding that matched Schneeberger’s (2010); however, factor analytic results did not support the hypothesized subscale structure of the LCI-R. Although cNDErs did not score significantly higher than nNDErs on the total scale or …
Date: August 2011
Creator: Goza, Tracy H.
Object Type: Thesis or Dissertation
System: The UNT Digital Library