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Acculturation Level, Generational Status and Gender: Their Role in Acculturative Stress in Young Adolescent Mexican Americans (open access)

Acculturation Level, Generational Status and Gender: Their Role in Acculturative Stress in Young Adolescent Mexican Americans

The purpose of this study was to determine relationships between acculturation level, generational status, and gender with acculturative stress. Acculturation level was determined by the Acculturation Rating Scale for Mexican Americans-II (ARSMA-II) and acculturative stress was determined by the Societal, Attitudinal, Familial and Environmental Acculturative Stress Scale-Children's Version (SAFE-C). Subjects included 1268 Hispanic children ages 11-15. In order to validate the usefulness of the ARSMA-II with this sample, analyses were conducted between acculturation level and generational status. The Pearson product moment correlation (r=.44) and the ANOVA between the mean acculturation score and generational status were significant. However, the mean acculturation score from this study was considerably lower than the ARSMA-II score; therefore, new acculturation levels were developed to establish local adolescent norms for the ARSMA-II. All analyses involving acculturation levels were conducted using both the ARSMA-II and new acculturation levels because 300 subjects were reclassified with the new norms. Significant results were similar using both acculturation levels; however, there were more between group differences using the new acculturation levels. It was hypothesized that as acculturation level increased toward the Anglo culture, acculturative stress would decrease. The one-way ANOVA confirmed this relationship. It was also hypothesized that as generational status increased, …
Date: August 2004
Creator: Manning, Suzanne C.
System: The UNT Digital Library
N-Acylethanolamine Metabolism During Seed Germination: Molecular Identification of a Functional N-Acylethanolamine Amidohydrolase (open access)

N-Acylethanolamine Metabolism During Seed Germination: Molecular Identification of a Functional N-Acylethanolamine Amidohydrolase

N-Acylethanolamines (NAEs) are endogenous lipid metabolites that occur in a variety of dry seeds, and their levels decline rapidly during the first few hours of imbibition (Chapman et al., 1999, Plant Physiol., 120:1157-1164). Biochemical studies supported the existence of an NAE amidohydrolase activity in seeds and seedlings, and efforts were directed toward identification of DNA sequences encoding this enzyme. Mammalian tissues metabolize NAEs via an amidase enzyme designated fatty acid amide hydrolase (FAAH). Based on the characteristic amidase signature sequence in mammalian FAAH, a candidate Arabidopsis cDNA was identified and isolated by reverse transcriptase-PCR. The Arabidopsis cDNA was expressed in E. coli and the recombinant protein indeed hydrolyzed a range of NAEs to free fatty acids and ethanolamine. Kinetic parameters for the recombinant protein were consistent with those properties of the rat FAAH, supporting identification of this Arabidopsis cDNA as a FAAH homologue. Two T-DNA insertional mutant lines with disruptions in the Arabidopsis NAE amidohydrolase gene (At5g64440) were identified. The homozygous mutant seedlings were more sensitive than the wild type to exogenously applied NAE 12:0. Transgenic seedlings overexpressing the NAE amidohydrolase enzyme showed noticeably greater tolerance to NAE 12:0 than wild type seedlings. These results together provide evidence in vitro …
Date: August 2004
Creator: Shrestha, Rhidaya
System: The UNT Digital Library
Adapting Filial Therapy for Families who have a Child with a Life-Threatening Illness (open access)

Adapting Filial Therapy for Families who have a Child with a Life-Threatening Illness

Utilizing a collective case study design, I examined and described the filial therapy (FT) process and adaptations discovered to be necessary and unnecessary in working with families who have a child with a life-threatening illness in the hospital setting. Data from a total of 7 parents was utilized, including those who terminated early, in order to gain a greater understanding of adapting FT for families who have a child with a life-threatening illness and their participation patterns. The parents attended 10 one- to two-hour FT sessions. The data was analyzed to examine for themes, patterns and relationships intrinsically with each case participant, as well as across cases. Analysis indicated that parents with a child with a life-threatening illness had great difficulty committing to attend FT; and a high rate of attrition occurred for those who did commit. A theme regarding flexibility was found to be of eminent importance in a variety of manifestations including therapeutic methods, session format, location and time of sessions, and intense vs traditional FT. Therapeutic adaptations in flexibility found to be important including openness to cathartic and personal parenting sessions, tolerance of forgetfulness, and lowering typical therapeutic concerns of dependency in the relationship. An inability for …
Date: August 2004
Creator: Steen, Rheta LeAnne
System: The UNT Digital Library
Adaptive Planning and Prediction in Agent-Supported Distributed Collaboration. (open access)

Adaptive Planning and Prediction in Agent-Supported Distributed Collaboration.

Agents that act as user assistants will become invaluable as the number of information sources continue to proliferate. Such agents can support the work of users by learning to automate time-consuming tasks and filter information to manageable levels. Although considerable advances have been made in this area, it remains a fertile area for further development. One application of agents under careful scrutiny is the automated negotiation of conflicts between different user's needs and desires. Many techniques require explicit user models in order to function. This dissertation explores a technique for dynamically constructing user models and the impact of using them to anticipate the need for negotiation. Negotiation is reduced by including an advising aspect to the agent that can use this anticipation of conflict to adjust user behavior.
Date: December 2004
Creator: Hartness, Ken T. N.
System: The UNT Digital Library
Adherence/Diffusion Barrier Layers for Copper Metallization: Amorphous Carbon:Silicon Polymerized Films (open access)

Adherence/Diffusion Barrier Layers for Copper Metallization: Amorphous Carbon:Silicon Polymerized Films

Semiconductor circuitry feature miniaturization continues in response to Moore 's Law pushing the limits of aluminum and forcing the transition to Cu due to its lower resistivity and electromigration. Copper diffuses into silicon dioxide under thermal and electrical stresses, requiring the use of barriers to inhibit diffusion, adding to the insulator thickness and delay time, or replacement of SiO2 with new insulator materials that can inhibit diffusion while enabling Cu wetting. This study proposes modified amorphous silicon carbon hydrogen (a-Si:C:H) films as possible diffusion barriers and replacements for SiO2 between metal levels, interlevel dielectric (ILD), or between metal lines (IMD), based upon the diffusion inhibition of previous a-Si:C:H species expected lower dielectric constants, acceptable thermal conductivity. Vinyltrimethylsilane (VTMS) precursor was condensed on a titanium substrate at 90 K and bombarded with electron beams to induce crosslinking and form polymerized a-Si:C:H films. Modifications of the films with hydroxyl and nitrogen was accomplished by dosing the condensed VTMS with water or ammonia before electron bombardment producing a-Si:C:H/OH and a-Si:C:H/N and a-Si:C:H/OH/N polymerized films in expectation of developing films that would inhibit copper diffusion and promote Cu adherence, wetting, on the film surface. X-ray Photoelectron Spectroscopy was used to characterize Cu metallization of …
Date: May 2004
Creator: Pritchett, Merry
System: The UNT Digital Library
Age and Responses to the Events of September 11, 2001 (open access)

Age and Responses to the Events of September 11, 2001

Following the terrorist attacks on the United States on September 11, 2001, many turned to the field of psychology for greater understanding of the impact of such events and guidance in supporting our citizens. This study sought to gain greater understanding of the differential impact of the September 11th attack on individuals by investigating the influence of age, psychological hardiness, and repression versus sensitization as forms of coping behavior on psychological health. Both an initial cross-sectional sample (172 young adults & 231older adults) and a short-term longitudinal follow-up (39 young adults & 58 older adults) were included in the study. Older age, psychological hardiness and the use of a repressing coping style were found to each individually relate to greater resilience/less dysfunction at both time one and two. For young adults, high hardy repressors faired best, followed by high hardy sensitizers. Low hardy young adults demonstrated similar levels of dysfunction regardless of coping style (repressions/sensitization). For older adults, coping style impacted both high and low hardy individuals equally, with high hardy repressors demonstrating greater functioning. This study attempted to gain greater insight into explanations for these and previous findings of greater resilience among older adults. In explaining the greater resilience …
Date: December 2004
Creator: Holmes, D. Nicole
System: The UNT Digital Library
Ambient and elevated temperature fracture and cyclic-fatigue properties in a series of Al-containing silicon carbides (open access)

Ambient and elevated temperature fracture and cyclic-fatigue properties in a series of Al-containing silicon carbides

A series of in situ toughened, Al, B and C containing, silicon carbide ceramics (ABC-SiC) has been examined with Al contents varying from 3 to 7 wt%. With increasing Al additions, the grain morphology in the as-processed microstructures varied from elongated to bimodal to equiaxed, with a change in the nature of the grain-boundary film from amorphous to partially crystalline to fully crystalline. Fracture toughness and cyclic fatigue tests on these microstructures revealed that although the 7 wt.% Al containing material (7ABC) was extremely brittle, the 3 and particularly 5 wt.% Al materials (3ABC and 5ABC, respectively) displayed excellent crack-growth resistance at both ambient (25 C) and elevated (1300 C) temperatures. Indeed, no evidence of creep damage, in the form of grain-boundary cavitation, was seen at temperatures at 1300 C or below. The enhanced toughness of the higher Al-containing materials was associated with extensive crack bridging from both interlocking grains (in 3ABC) and uncracked ligaments (in 5ABC); in contrast, the 7ABC SiC showed no such bridging, concomitant with a marked reduction in the volume fraction of elongated grains. Mechanistically, cyclic fatigue-crack growth in 3ABC and 5ABC SiC involved the progressive degradation of such bridging ligaments in the crack wake, with …
Date: August 30, 2004
Creator: Yuan, Rong
System: The UNT Digital Library
An Analysis of Adler's Theory and the Female Criminal (open access)

An Analysis of Adler's Theory and the Female Criminal

This research paper addressed the following question: Do select case studies conform to Dr. Freda Adler's theory regarding socio-economic influences on female criminal behavior or dispute her theory? My research involved three female criminals: Karla Faye Tucker, Andrea Yates, and Susan Smith. I addressed Adler's theory in detail, other theories, the makeup of the female criminal and various female crimes. This study provided evidence that all three case studies conform to Adler's theory. nIn accordance with Adler's theory, each of these three females committed crimes of accessibility. None of the three individuals sought to commit a premeditated act or to murder unknown victims. They were motivated by emotions arising at a point in time when access/opportunity presented itself.
Date: August 2004
Creator: Armentrout, Elizabeth G.
System: The UNT Digital Library
An Analysis of Advisory Committee Activities in a Successful Public School Bond Election (open access)

An Analysis of Advisory Committee Activities in a Successful Public School Bond Election

The purpose of this study was to determine the perceived effectiveness of specific advisory committee activities during a school bond proposal and election process. The study began with an extensive review of the literature on the use of advisory committee activities in school districts for the purpose of promoting a school bond issue. This revealed that school officials maintaining a low profile, the presence of a diverse community task force, focusing on YES voters, involving the committee in early planning, focusing on disseminating information, and focusing on benefits to children and the community are all important in the passage of a school bond election. A survey was developed and administered to committee members, school board members and school district administrators in a North Texas school district that had successfully completed a bond election. Survey respondents consistently supported the practices put into place by the studied school district, which closely mirrored the activities espoused in the research. Respondents believed the diversity of the task force and the roles of the committee members to be crucial to the passage of the bond. The only subcategory of questions that drew mixed reviews and positions of support was that of the need for the …
Date: August 2004
Creator: Waters, Philo W.
System: The UNT Digital Library
Analysis of Leadership Perceptions Using Multirater Feedback. (open access)

Analysis of Leadership Perceptions Using Multirater Feedback.

Performance improvement intervention begins with assessment. How that assessment is interpreted can mean the difference between success and failure. Previous research of 360-degree feedback instruments has tried to reconcile the differences between multiple rater groups. Rather than searching for agreement, this research proposes to understand the meaning of the differences using multirater feedback. Individuals determine ratings based upon their own perspective and building upon the understanding of rater perspective may result in improved assessments. Data from an existing data set was processed using a second-order CFA in structural equation modeling. Covariance between the second-order factors and rater groups determined the difference in how each rater group perceived the leader.
Date: May 2004
Creator: Bradley, Thomas P.
System: The UNT Digital Library
Analysis of Perceptional Differences Among Department Chairs, Faculty, and Instructors Toward the Barrier to Using Multiple Teaching Strategies in Two-Year Technical and Community College Electronics Courses (open access)

Analysis of Perceptional Differences Among Department Chairs, Faculty, and Instructors Toward the Barrier to Using Multiple Teaching Strategies in Two-Year Technical and Community College Electronics Courses

The purpose of this study was to identify and analyze perceptional differences among department chairs, faculty, and instructors toward the barrier to using multiple teaching strategies in two-year technical and community college electronics courses. The literature review focused on defining multiple teaching strategies and identifying and discussing four major perceived barriers to implementing them in the electronics classroom: student, resources, classroom environmental, and teacher training/teaching technology. The targeted population consisted of 150 out of 231 electronics teaching technical and community college department chairs, faculty, and instructors throughout the state of Texas. In actuality, the targeted population's breakdown consisted of 36 full-time electronics teaching department chairs, 96 full-time electronics teaching faculty and instructors, and 18 part-time electronics teaching faculty and instructors who were actively involved in the delivery of instruction in their respective schools. Analysis of the data revealed that: (1) there are no significant differences among the perceptions of department chair people, faculty, and instructors toward the four perceived barriers to implementing multiple teaching strategies in a post-secondary electronics program; and (2) there are no significant differences in the perceptions electronics faculty members categorized by years teaching experience toward each of the four perceived barrier categories to implementing multiple teaching …
Date: May 2004
Creator: Hutyra, Jerry Emil
System: The UNT Digital Library
An Analysis of Terrorist Recruitment by Observing DHKP/C (Revolutionary People's Liberation Party/Front) Terrorist Organization in Turkey (open access)

An Analysis of Terrorist Recruitment by Observing DHKP/C (Revolutionary People's Liberation Party/Front) Terrorist Organization in Turkey

Terrorism has been claimed to be a major problem by hundreds of thousands of people in the international arena for years. Either it has been very difficult to determine and understand the reasons for terrorism, or those reasons have never been studied because of the immediate threat of terrorism. This research analyzed the recruitment process of terrorists by studying the DHKP/C terrorist organization and by answering the following questions. The first is "What factors are correlated with joining a terrorist organization?" And the second is "What is the recruitment process of the DHKP/C?" IN the course of this research, I used specific reports written by DHKP/C members and personal experience to come to better understanding of the motivation behind terrorism and the process by which people are recruited in the terrorist organizations.
Date: August 2004
Creator: Teymur, Samih
System: The UNT Digital Library
An Analysis of the Effect of Distance Learning on Student Self-Efficacy of Junior High School Spanish Students. (open access)

An Analysis of the Effect of Distance Learning on Student Self-Efficacy of Junior High School Spanish Students.

Prior to the development of interactive television, schools that were either geographically isolated or financially restricted were often unable to provide courses that may have been essential for students. Interactive television has helped such school districts provide appropriate courses for their students. Because student self-efficacy is a significant indicator of student success, the relationship between distance learning and students' self-efficacy requires research. The problem of the study was to examine the impact of site location in a distance learning environment on student self-efficacy in Spanish instruction. The participants in this study were junior high school students enrolled in distance-learning Spanish classes at two junior high schools in a north central Texas independent school district. All of the students were taught by the same instructor. The age range of the students was from 11 to 14 years of age, and all students were in either the seventh or the eighth grade. Students took a modified version of the Motivated Strategies for Learning Questionnaire at the end of each treatment. Using the counterbalanced design, each subject was matched to themselves. T-tests for nonindependent samples were used to compare the two treatments. The findings indicate that there is no significant difference in the …
Date: August 2004
Creator: Vroonland, David W.
System: The UNT Digital Library
An Analysis of the Genesis of Motive, Rhythm, and Pitch in the First Movement of the Sonata for Two Pianos and Percussion by Béla Bartók. (open access)

An Analysis of the Genesis of Motive, Rhythm, and Pitch in the First Movement of the Sonata for Two Pianos and Percussion by Béla Bartók.

This dissertation presents evidence that Béla Bartók created his masterwork, the Sonata for Two Pianos and Percussion (1937), in a very complex period of his life. Since it was a mature piece, Bartók utilized typically "Bartókian" compositional techniques and styles. His ethnomusicological studies were also influential factors in the creation of the Sonata for Two Pianos and Percussion. We can be witness to how different the first draft was to the published version; the minor and major changes are revealed in the draft study of the Sonata for Two Pianos and Percussion 's first movement. These changes allow today's musicians to reconstruct the compositional process. The first movement introduces some interesting uses of sonata form, to be explored in more detail in the analysis. Starting with linear analysis, the basic motives and rhythmic patterns are discussed and supported with Bartók's own explanations. The conclusion of this study has important ramifications for performance: it eases up the pressure on the performers, since problematic passages are analyzed and explained - preparing the players' mentally for the performance. This is music which is hard to play and difficult to analyze. The analysis, combining the results of both theoretical and musicological studies, is intended …
Date: May 2004
Creator: Ujj-Hilliard, Emöke
System: The UNT Digital Library
Analysis of the Semileptonic Decay D0 --> anti-K0 pi- mu+ nu (open access)

Analysis of the Semileptonic Decay D0 --> anti-K0 pi- mu+ nu

This thesis describes the analysis of the semileptonic decay D{sup 0} {yields} {bar K}{sup 0} {pi}{sup -} {mu}{sup +}{nu} using FOCUS data. FOCUS is a fixed target experiment at Fermilab that studies the physics of the charm quark. Particles containing charm are produced by photon-gluon fusion from the collision of a photon beam on a BeO target. The experiment is characterized by excellent vertex resolution and particle identification. The spectrometer consists of three systems for track reconstruction (two silicon systems and one multiwire proportional chamber system) and two magnets of opposite polarity. The polarity of the magnet is such that the events of e{sup +}e{sup -} pairs produced in the target (which constitutes the main background) travel through a central opening in the detectors without interactions. Particle momentum is measured from the deflection angle in the magnets. Three multicell Cerenkov counters are used for charged particle identification (for e, {pi}, K, and p). Two different tracking systems located after several interaction lengths of shielding material are used for muon identification. The energy of neutral pions and electrons is measured in two electromagnetic calorimeters, while an hadron calorimeter is used for measuring the neutron energy. During the last four years the …
Date: November 1, 2004
Creator: Segoni, Ilaria Maria Lucia
System: The UNT Digital Library
Analysis of Web Services on J2EE Application Servers (open access)

Analysis of Web Services on J2EE Application Servers

The Internet became a standard way of exchanging business data between B2B and B2C applications and with this came the need for providing various services on the web instead of just static text and images. Web services are a new type of services offered via the web that aid in the creation of globally distributed applications. Web services are enhanced e-business applications that are easier to advertise and easier to discover on the Internet because of their flexibility and uniformity. In a real life scenario it is highly difficult to decide which J2EE application server to go for when deploying a enterprise web service. This thesis analyzes the various ways by which web services can be developed & deployed. Underlying protocols and crucial issues like EAI (enterprise application integration), asynchronous messaging, Registry tModel architecture etc have been considered in this research. This paper presents a report by analyzing what various J2EE application servers provide by doing a case study and by developing applications to test functionality.
Date: May 2004
Creator: Gosu, Adarsh Kumar
System: The UNT Digital Library
The Anatomy of Academic Dishonesty: Cognitive Development, Self-Concept, Neutralization Techniques, and Attitudes Toward Cheating (open access)

The Anatomy of Academic Dishonesty: Cognitive Development, Self-Concept, Neutralization Techniques, and Attitudes Toward Cheating

This study explored the relationship between cheating among university students and their cognitive developmental levels, use of neutralization techniques, self-concept as a multifaceted cognitive construct, and attitude toward cheating. The purposes of this study were to investigate: (1) The relationships between academic dishonesty and each of the following overall independent variables: cognitive development, use of neutralization techniques, self-concept as a multifaceted cognitive construct, and attitude toward cheating, and (2) the reasons behind college student academic cheating behaviors. The study used data from anonymous, self-report surveys administered to undergraduate students in-class and at supplemental sessions. Student participation was voluntary. The study was correlational. The five hypotheses were: (1) Self-concept is significantly and negatively related to academic dishonesty; (2) Cognitive development is significantly and negatively related to academic dishonesty; (3) Attitude toward cheating is significantly and negatively related to academic dishonesty; (4) The use of neutralization techniques is significantly and positively related to academic dishonesty; (5) Cognitive development, self-concept, and attitude toward cheating will make significant contributions to the regression model for the dependent variables of academic dishonesty. The data supported the first, third, and fourth hypotheses. However, the second and fifth hypotheses were supported under certain conditions. The roles of cognitive …
Date: August 2004
Creator: Arvidson, Cody Jean
System: The UNT Digital Library
Appellate Recruitment Patterns in the Higher British Judiciary: 1850 - 1990 (open access)

Appellate Recruitment Patterns in the Higher British Judiciary: 1850 - 1990

This study seeks to advance the understanding of appellate promotion in the senior judiciary of Great Britain . It describes the population and attributes of judges who served in the British High Courts, Court of Appeal, and Appellate Committee of the House of Lords (i.e., Law Lords) from 1850 to 1990. It specifically builds upon the work of C. Neal Tate and tests his model of appellate recruitment on a larger and augmented database. The study determines that family status, previously asserted as having a large effect on recruitment to the appellate courts, is not as important as previously believed. It concludes that merit effects, professional norms, and institutional constraints offer equally satisfactory or better explanations of appellate recruitment patterns.
Date: December 2004
Creator: Thomas, Bruce K.
System: The UNT Digital Library

Application of Cultured Neuronal Networks for Use as Biological Sensors in Water Toxicology and Lipid Signaling.

Access: Use of this item is restricted to the UNT Community
This dissertation research explored the capabilities of neuronal networks grown on substrate integrated microelectrode arrays in vitro to be applied to toxicological research and lipid signaling. Chapter 1 details the effects of chlorine on neuronal network spontaneous electrical activity and pharmacological sensitivity. This study demonstrates that neuronal networks can maintain baseline spontaneous activity, and respond normally to pharmacological manipulations in the present of three times the chlorine present in drinking water. The findings suggest that neuronal networks may be used as biological sensors to monitor the quality of water and the presence of novel toxicants that cannot be detected by conventional sensors. Chapter 2 details the neuromodulatory effects of N-acylethanolamides (NAEs) on the spontaneous electrical activity of neuronal networks. NAEs are a group of lipids that can mimic the effects of marijuana and can be derived from a variety of plant sources including soy lecithin. The most prominent NAEs in soy lecithin, palmitoylethanolamide (PEA) and linoleoylethanolamide (LEA), were tested individually and were found to significantly inhibit neuronal spiking and bursting activity. These effects were potentiated by a mixture of NAEs as found in a HPLC enriched fraction from soy lecithin. Cannabinoid receptor-1 (CB1-R) antagonists and other cannabinoid pathway modulators indicated …
Date: August 2004
Creator: Dian, Emese Emöke
System: The UNT Digital Library
Application of optimal prediction to molecular dynamics (open access)

Application of optimal prediction to molecular dynamics

Optimal prediction is a general system reduction technique for large sets of differential equations. In this method, which was devised by Chorin, Hald, Kast, Kupferman, and Levy, a projection operator formalism is used to construct a smaller system of equations governing the dynamics of a subset of the original degrees of freedom. This reduced system consists of an effective Hamiltonian dynamics, augmented by an integral memory term and a random noise term. Molecular dynamics is a method for simulating large systems of interacting fluid particles. In this thesis, I construct a formalism for applying optimal prediction to molecular dynamics, producing reduced systems from which the properties of the original system can be recovered. These reduced systems require significantly less computational time than the original system. I initially consider first-order optimal prediction, in which the memory and noise terms are neglected. I construct a pair approximation to the renormalized potential, and ignore three-particle and higher interactions. This produces a reduced system that correctly reproduces static properties of the original system, such as energy and pressure, at low-to-moderate densities. However, it fails to capture dynamical quantities, such as autocorrelation functions. I next derive a short-memory approximation, in which the memory term is …
Date: December 1, 2004
Creator: Barber IV, John Letherman
System: The UNT Digital Library
Art or Craft? (open access)

Art or Craft?

I chose to exhibit sculpture and classical style vessels together to encourage discussion about whether ceramics should be considered a fine art medium. I was interested in experimenting with different forms and textures in order to see which combination would captivate the viewing audience the longest. I found that massive textural sculptural forms held the attention of the viewer more so than did the classical smooth surfaced vessels.
Date: May 2004
Creator: Snelson, Jason
System: The UNT Digital Library
Aspects of the SrO-CuO-TiO2 Ternary System Related to the Deposition of SrTiO3 and Copper-Doped SrTiO3 Thin-Film Buffer Layers (open access)

Aspects of the SrO-CuO-TiO2 Ternary System Related to the Deposition of SrTiO3 and Copper-Doped SrTiO3 Thin-Film Buffer Layers

YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) coated conductors are promising materials for large-scale superconductivity applications. One version of a YBCO coated conductor is based on ion beam assisted deposition (IBAD) of magnesium oxide (MgO) onto polycrystalline metal substrates. SrTiO{sub 3} (STO) is often deposited by physical vapor deposition (PVD) methods as a buffer layer between the YBCO and IBAD MgO due to its chemical stability and lattice mismatch of only {approx}1.5% with YBCO. In this work, some aspects of the stability of STO with respect to copper (Cu) and chemical solution deposition of STO on IBAD MgO templates were examined. Solubility limits of Cu in STO were established by processing Cu-doped STO powders by conventional bulk preparation techniques. The maximum solubility of Cu in STO was {approx}1% as determined by transmission electron microscopy (TEM) and Rietveld refinements of x-ray diffraction (XRD) data. XRD analysis, performed in collaboration with NIST, on powder compositions on the STO/SrCuO{sub 2} tie line did not identify any ternary phases. SrCu{sub 0.10}Ti{sub 0.90}O{sub y} buffer layers were prepared by pulsed laser deposition (PLD) and CSD on IBAD MgO flexible metallic textured tapes. TEM analysis of a {approx}100 nm thick SrCu{sub 0.10}Ti{sub 0.90}O{sub y} buffer layer deposited by …
Date: December 20, 2004
Creator: Ayala, A.
System: The UNT Digital Library
Aspherical supernovae (open access)

Aspherical supernovae

Although we know that many supernovae are aspherical, the exact nature of their geometry is undetermined. Because all the supernovae we observe are too distant to be resolved, the ejecta structure can't be directly imaged, and asymmetry must be inferred from signatures in the spectral features and polarization of the supernova light. The empirical interpretation of this data, however, is rather limited--to learn more about the detailed supernova geometry, theoretical modeling must been undertaken. One expects the geometry to be closely tied to the explosion mechanism and the progenitor star system, both of which are still under debate. Studying the 3-dimensional structure of supernovae should therefore provide new break throughs in our understanding. The goal of this thesis is to advance new techniques for calculating radiative transfer in 3-dimensional expanding atmospheres, and use them to study the flux and polarization signatures of aspherical supernovae. We develop a 3-D Monte Carlo transfer code and use it to directly fit recent spectropolarimetric observations, as well as calculate the observable properties of detailed multi-dimensional hydrodynamical explosion simulations. While previous theoretical efforts have been restricted to ellipsoidal models, we study several more complicated configurations that are tied to specific physical scenarios. We explore clumpy …
Date: May 21, 2004
Creator: Kasen, Daniel Nathan
System: The UNT Digital Library

Asserting Identity in Wagner's Shadow: The Case of Engelbert Humperdinck's Königskinder (1897)

Access: Use of this item is restricted to the UNT Community
Engelbert Humperdinck (1854-1921), who was considered a Wagnerian due to to his past work in Bayreuth and the Wagnerian traits of his Hänsel und Gretel, seems to have believed that to define himself as a composer, he had to engage somehow with that designation, whether through orthodox Wagner imitation or an assertion of his independence from Wagner's musical legacy. The latter kind of engagement can be seen in Humperdinck's Königskinder (1897), in which he developed a new kind of declamatory notation within the context of melodrama, thus fulfilling Wagnerian ideals as well as progressing beyond them. The effectiveness of Humperdinck's effort is seen in the ensuing critical reception, in which the realities of being heard as a Wagnerian composer are clarified.
Date: August 2004
Creator: Kinnett, Forest Randolph
System: The UNT Digital Library