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Primarily Thai

Description: This thesis is a production report that describes the research process, pre-production and post-production stages of making a documentary about the Thai language school in the Thai temple in Dallas County. The film documents the teachers from Chulalongkorn University who volunteered to teach Thai-American students in the United States, and explores Thai-American students' attitudes toward the school and their heritage.
Date: May 1998
Creator: Phatthanodom, Fahmui
Partner: UNT Libraries

Assessing the feasibility of developing a DBAE curriculum in Qatar utilizing multimedia technology

Description: The purpose of this study was to demonstrate the feasibility of developing an art curriculum in Qatar, using the principles of the DBAE curriculum in conjunction with technology. Many of the challenges facing art educators and the art curriculum in Qatar can be approached through the multimedia applications of DBAE, which will provide instructors and students with an opportunity to more readily interact with visual art and to discover its educational relevance. Additionally, this study attempted to discover whether teachers are engaged in implementing technology in the art classroom and whether they are given the opportunity to engage in art to their satisfaction.
Date: May 1998
Creator: Al-Hamad, Wafaa
Partner: UNT Libraries

Shifts of focus among dimensions of user information problems as represented during interactive information retrieval

Description: The goal of this study is to increase understanding of information problems as they are revealed in interactions among users and search intermediaries during information retrieval. Specifically, this study seeks to investigate: (a) how interaction between users and search intermediaries reveals aspects of user information problems; (b) to explore the concept of representation with respect to information problems in interactive information retrieval; and (c) how user and search intermediaries focus on aspects of user information problems during the course of searches.
Date: May 1998
Creator: Robins, David B. (David Bruce)
Partner: UNT Libraries

A guide for the preparation, analysis and performance of the brass quintet literature of Thom Ritter George, with three recitals of selected works by Bach, Bitsch, Handel, Torelli, Suderberg, Ketting and others

Description: An examination of the musical style, compositional techniques and performance practice issues of American composer Thom Ritter George with special attention paid to his Quintet No. 4 written in 1986. The document also includes a short history of brass instruments in chamber music, history of the brass quintet in America, discussion of the role of the trumpet in the quintet, overview of the composers contributions to music and brass quintet in America, discussion of the role of the trumpet in the quintet, overview of the composers contributions to music and brass quintet, and background information on the composer.
Date: May 1998
Creator: Stowman, William J. (William John)
Partner: UNT Libraries

A transcription of three arias from The barber of Seville, by Gioacchino Rossini, for solo euphonium and large brass ensemble, with three recitals of selected works by E. Bozza, A. Capuzzi, J. Koetsier, A. Ponchielli, and others

Description: Document accompanying a transcription for solo euphonium and large brass ensemble of three arias, "Ecco ridente in cielo," "Largo al factotum," and "A un dottor della mia sorte," from Gioacchino Rossini's opera The Barber of Seville. Includes overviews of the arias' texts and contexts, orchestrational techniques in the transcriptions, the history and definition of the term "euphonium," and the history of the large brass ensemble in the United States.
Date: May 1998
Creator: Pollard, Louis M. (Louis Melvin)
Partner: UNT Libraries

An epidemiological survey of musculoskeletal pain among a self-selected population of organists

Description: The purpose of this study was to investigate problem areas of organists' performance as indicated by common experiences of pain. The research problems were to determine the specific areas of the body that were affected by pain, to determine the perceived level of that pain on a scale indicative of its severity, and to explore the relationship between demographic and performance-related factors within the population and specific area of reported pain.
Date: May 1998
Creator: Dillard, E. Margo (Edna Margo)
Partner: UNT Libraries

The influence of surface topography on the forming friction of automotive aluminum sheet

Description: Interest in utilizing aluminum alloys in automobiles has increased in recent years as a result of the desire to lower automobile weight and, consequently, increase fuel economy. While aluminum alloy use in cast parts has increased, outer body panel applications are still being investigated. The industry is interested in improving the formability of these sheet alloys by a combination of alloy design and processing. A different avenue of improving the formability of these alloys may be through patterning of the sheet surface. Surface patterns hold the lubricant during the forming process, with a resulting decrease in the sheet-die surface contact. While it has been speculated that an optimum surface pattern would consist of discrete cavities, detailed investigation into the reduction of forming friction by utilizing discrete patterns is lacking. A series of discrete patterns were investigated to determine the dependence of the forming friction of automotive aluminum alloys on pattern lubricant carrying capacity and on material strength. Automotive aluminum alloys used in outer body panel applications were rolled on experimental rolls that had been prepared with a variety of discrete patterns. All patterns for each alloy were characterized before and after testing both optically and, to determine pattern lubricant capacity, using three dimensional laser profilometry. A draw bead simulation (DBS) friction tester was designed and fabricated to determine the forming friction of the patterned sheets. Tensile testing and frictionless DBS testing were performed to ascertain the material properties of each sheet. The most striking result of this work was the inversely linear dependence of forming friction on the lubricant carrying capacity of the discrete patterns.
Date: May 1, 1998
Creator: Kramer, P.A.
Partner: UNT Libraries Government Documents Department

Production of low axial energy spread ion beams with multicusp sources

Description: Multicusp ion sources are capable of producing ions with low axial energy spread which are necessary in applications such as: ion projection lithography (IPL) and focused ion beams for the next generation lithographic tools and nuclear science experiments such as radioactive ion beam production. The axial ion energy spread for multicusp source is approximately 6 eV which is too large for IPL and radioactive ion beam applications. The addition of a magnetic filter which consists of a pair of permanent magnets to the multicusp source reduces the energy spread considerably. The reduction is due to the improvement in the uniformity of the axial plasma potential distribution in the discharge region. Axial ion energy spread of the filament driven ion source has been measured using three different techniques. In all cases, it was found to be less than 2 eV. Energy spread of the radio frequency (RF) driven source has also been explored, and it was found to be less than 3 eV with the proper RF-shielding. A new multicusp source configuration has been designed and constructed to further reduce the energy spread. To achieve a more uniform axial plasma potential distribution, a cylindrical magnetic filter has been designed and constructed for a 2-cm-diameter source. This new source configuration, the co-axial source, is new in its kind. The energy spread in this source has been measured to be a record low of 0.6 eV. Because of the novelty of this device, some plasma parameters inside the source have been studied. Langmuir probe has been used to measure the plasma potential, the electron temperature and the density distribution.
Date: May 1, 1998
Creator: Lee, Y.H.Y.
Partner: UNT Libraries Government Documents Department

The applicability of certain Monte Carlo methods to the analysis of interacting polymers

Description: The authors consider polymers, modeled as self-avoiding walks with interactions on a hexagonal lattice, and examine the applicability of certain Monte Carlo methods for estimating their mean properties at equilibrium. Specifically, the authors use the pivoting algorithm of Madras and Sokal and Metroplis rejection to locate the phase transition, which is known to occur at {beta}{sub crit} {approx} 0.99, and to recalculate the known value of the critical exponent {nu} {approx} 0.58 of the system for {beta} = {beta}{sub crit}. Although the pivoting-Metropolis algorithm works well for short walks (N < 300), for larger N the Metropolis criterion combined with the self-avoidance constraint lead to an unacceptably small acceptance fraction. In addition, the algorithm becomes effectively non-ergodic, getting trapped in valleys whose centers are local energy minima in phase space, leading to convergence towards different values of {nu}. The authors use a variety of tools, e.g. entropy estimation and histograms, to improve the results for large N, but they are only of limited effectiveness. Their estimate of {beta}{sub crit} using smaller values of N is 1.01 {+-} 0.01, and the estimate for {nu} at this value of {beta} is 0.59 {+-} 0.005. They conclude that even a seemingly simple system and a Monte Carlo algorithm which satisfies, in principle, ergodicity and detailed balance conditions, can in practice fail to sample phase space accurately and thus not allow accurate estimations of thermal averages. This should serve as a warning to people who use Monte Carlo methods in complicated polymer folding calculations. The structure of the phase space combined with the algorithm itself can lead to surprising behavior, and simply increasing the number of samples in the calculation does not necessarily lead to more accurate results.
Date: May 1, 1998
Creator: Krapp, D.M. Jr.
Partner: UNT Libraries Government Documents Department

Ultrashort X-ray pulse science

Description: A variety of phenomena involves atomic motion on the femtosecond time-scale. These phenomena have been studied using ultrashort optical pulses, which indirectly probe atomic positions through changes in optical properties. Because x-rays can more directly probe atomic positions, ultrashort x-ray pulses are better suited for the study of ultrafast structural dynamics. One approach towards generating ultrashort x-ray pulses is by 90{sup o} Thomson scattering between terawatt laser pulses and relativistic electrons. Using this technique, the author generated {approx} 300 fs, 30 keV (0.4 {angstrom}) x-ray pulses. These x-ray pulses are absolutely synchronized with ultrashort laser pulses, allowing femtosecond optical pump/x-ray probe experiments to be performed. Using the right-angle Thomson scattering x-ray source, the author performed time-resolved x-ray diffraction studies of laser-perturbated InSb. These experiments revealed a delayed onset of lattice expansion. This delay is due to the energy relaxation from a dense electron-hole plasma to the lattice. The dense electron-hole plasma first undergoes Auger recombination, which reduces the carrier concentration while maintaining energy content. Longitudinal-optic (LO) phonon emission then couples energy to the lattice. LO phonon decay into acoustic phonons, and acoustic phonon propagation then causes the growth of a thermally expanded layer. Source characterization is instrumental in utilizing ultrashort x-ray pulses in time-resolved x-ray spectroscopies. By measurement of the electron beam diameter at the generation point, the pulse duration of the Thomson scattered x-rays is determined. Analysis of the Thomson scattered x-ray beam properties also provides a novel means of electron bunch characterization. Although the pulse duration is inferred for the Thomson scattering x-ray source, direct measurement is required for other x-ray pulse sources. A method based on the laser-assisted photoelectric effect (LAPE) has been demonstrated as a means of measuring ultrashort x-ray pulse durations. LAPE may also serve as the basis for a gated x-ray detector.
Date: May 1, 1998
Creator: Chin, A.H.
Partner: UNT Libraries Government Documents Department

Effect of uniaxial stress on gallium, beryllium, and copper-doped germanium hole population inversion lasers

Description: The effects of stress on germanium lasers doped with single, double, and triple acceptors have been investigated. The results can be explained quantitatively with theoretical calculations and can be attributed to specific changes in the energy levels of acceptors in germanium under stress. In contrast to previous measurements, gallium-doped Ge crystals show a decrease in lasing upon uniaxial stress. The decrease seen here is attributed to the decrease in heavy hole effective mass upon application of uniaxial stress, which results in a decreased population inversion. The discrepancy between this work and previous studies can be explained with the low compensation level of the material used here. Because the amount of ionized impurity scattering in low-compensated germanium lasers is small to begin with, the reduction in scattering with uniaxial stress does not play a significant role in changing the laser operation. Beryllium-doped germanium lasers operate based on a different mechanism of population inversion. In this material it is proposed that holes can transfer between bands by giving their energy to a neutral beryllium atom, raising the hole from the ground to a bound excited state. The free hole will then return to zero energy with some probability of entering the other band. The minimum and maximum E/B ratios for lasing change with uniaxial stress because of the change in effective mass and bound excited state energy. These limits have been calculated for the case of 300 bar [100] stress, and match very well with the observed data. This adds further credence to the proposed mechanism for population inversion in this material. In contrast to Be and Ga-doped lasers, copper-doped lasers under uniaxial stress show an increase in the range of E and B where lasing is seen. To understand this change the theoretical limits for population inversion based on both the ...
Date: May 1998
Creator: Chamberlin, D. R.
Partner: UNT Libraries Government Documents Department

The phase space of the focused cubic Schroedinger equation: A numerical study

Description: In a paper of 1988 [41] on statistical mechanics of the nonlinear Schroedinger equation, it was observed that a Gibbs canonical ensemble associated with the nonlinear Schroedinger equation exhibits behavior reminiscent of a phase transition in classical statistical mechanics. The existence of a phase transition in the canonical ensemble of the nonlinear Schroedinger equation would be very interesting and would have important implications for the role of this equation in modeling physical phenomena; it would also have an important bearing on the theory of weak solutions of nonlinear wave equations. The cubic Schroedinger equation, as will be shown later, is equivalent to the self-induction approximation for vortices, which is a widely used equation of motion for a thin vortex filament in classical and superfluid mechanics. The existence of a phase transition in such a system would be very interesting and actually very surprising for the following reasons: in classical fluid mechanics it is believed that the turbulent regime is dominated by strong vortex stretching, while the vortex system described by the cubic Schroedinger equation does not allow for stretching. In superfluid mechanics the self-induction approximation and its modifications have been used to describe the motion of thin superfluid vortices, which exhibit a phase transition; however, more recently some authors concluded that these equations do not adequately describe superfluid turbulence, and the absence of a phase transition in the cubic Schroedinger equation would strengthen their argument. The self-induction approximation for vortices takes into account only very localized interactions, and the existence of a phase transition in such a simplified system would be very unexpected. In this thesis the authors present a numerical study of the phase transition type phenomena observed in [41]; in particular, they find that these phenomena are strongly related to the splitting of the phase space into distinctly ...
Date: May 1, 1998
Creator: Burlakov, Y.O.
Partner: UNT Libraries Government Documents Department

Effects of pore fluids in the subsurface on ultrasonic wave propagation

Description: This thesis investigates ultrasonic wave propagation in unconsolidated sands in the presence of different pore fluids. Laboratory experiments have been conducted in the sub-MHz range using quartz sand fully saturated with one or two liquids. Elastic wave propagation in unconsolidated granular material is computed with different numerical models: in one-dimension a scattering model based on an analytical propagator solution, in two dimensions a numerical approach using the boundary integral equation method, in three dimensions the local flow model (LFM), the combined Biot and squirt flow theory (BISQ) and the dynamic composite elastic medium theory (DYCEM). The combination of theoretical and experimental analysis yields a better understanding of how wave propagation in unconsolidated sand is affected by (a) homogeneous phase distribution; (b) inhomogeneous phase distribution, (fingering, gas inclusions); (c) pore fluids of different viscosity; (d) wettabilities of a porous medium. The first study reveals that the main ultrasonic P-wave signatures, as a function of the fraction on nonaqueous-phase liquids in initially water-saturated sand samples, can be explained by a 1-D scattering model. The next study investigates effects of pore fluid viscosity on elastic wave propagation, in laboratory experiments conducted with sand samples saturated with fluids of different viscosities. The last study concentrates on the wettability of the grains and its effect on elastic wave propagation and electrical resistivity.
Date: May 1, 1998
Creator: Seifert, P.K.
Partner: UNT Libraries Government Documents Department

Advanced far infrared blocked impurity band detectors based on germanium liquid phase epitaxy

Description: This research has shown that epilayers with residual impurity concentrations of 5 x 10{sup 13} cm{sup {minus}3} can be grown by producing the purest Pb available in the world. These epilayers have extremely low minority acceptor concentrations, which is ideal for fabrication of IR absorbing layers. The Pb LPE growth of Ge also has the advantageous property of gettering Cu from the epilayer and the substrate. Epilayers have been grown with intentional Sb doping for IR absorption on lightly doped substrates. This research has proven that properly working Ge BIB detectors can be fabricated from the liquid phase as long as pure enough solvents are available. The detectors have responded at proper wavelengths when reversed biased even though the response did not quite reach minimum wavenumbers. Optimization of the Sb doping concentration should further decrease the photoionization energy of these detectors. Ge BIB detectors have been fabricated that respond to 60 cm{sup {minus}1} with low responsivity. Through reduction of the minority residual impurities, detector performance has reached responsivities of 1 A/W. These detectors have exhibited quantum efficiency and NEP values that rival conventional photoconductors and are expected to provide a much more sensitive tool for new scientific discoveries in a number of fields, including solid state studies, astronomy, and cosmology.
Date: May 1, 1998
Creator: Olsen, C.S.
Partner: UNT Libraries Government Documents Department

Synthesis of the Personal and the Political in the Works of May Stevens

Description: This thesis is an investigation of the way in which the painter May Stevens (b. 1924) synthesizes her personal experiences and political philosophy to form complex and enduring works of art. Primary data was accumulated through an extended interview with May Stevens and by examining her works on exhibit in New York and Boston. An analysis of selected works from her "Big Daddy" and "Ordinary/Extraordinary" series revealed how her personal feelings about her own family became entwined with larger political issues. As an important member of the feminist art movement that evolved during the 1970s, she celebrated this new kinship among women in paintings that also explored the contradictions in their lives. In more recent work she has explored complex social issues such as teenage prostitution, sexism, and child abuse in a variety of artistic styles and media. This study investigates how May Stevens continues to portray issues of international significance in works that consistently engage the viewer on a personal, almost visceral level.
Date: May 1998
Creator: Abbott, Janet Gail
Partner: UNT Libraries

Mandatory Continuing Education in Nursing: a Texas Perspective

Description: This study investigated Texas nurses' attitudes toward mandatory continuing education, and their perceptions of skill improvement, knowledge enrichment and improvement of health care to the public as a result of participation in twenty contact hours of continuing education programs as required by the Board of Nurse Examiners for the State of Texas. This sample of Texas nurses felt that the goals set forth by the Board of Nurse Examiners for the State of Texas had been met by participation in mandatory continuing education. However, given the small return rate, the attitudes of these nurses may not represent the attitudes of the majority of Texas nurses.
Date: May 1998
Creator: Prater, Llewellyn Swan
Partner: UNT Libraries

Characterization of Aspartate Transcarbamoylase and Dihydroorotase in Moraxella Catarrhalis

Description: Bacterial aspartate transcarbamoylases (ATCase's) are divided into three classes that correspond to taxonomic relationships within the bacteria. The opportunistic pathogen Moraxeila catarrhalis has undergone several reclassifications based on traditional microbiological criteria. The previously uncharacterized ATCase from M. catarrhalis was purified to homogeneity and its chemical properties characterized. The ATCase from M. catarrhalis is a class C ATCase with an apparent molecular mass of 480-520 kDa. The M. catarrhalis ATCase is a dodecomer composed of six 35 kDa polypeptides and six 45 kDa polypeptides. The enzyme has an unusually high pH optimum of greater than pH 10. The enzyme exhibited hyperbolic kinetic with a Km for aspartate of 2 mM. A single, separate 78 kDa dihydroorotase from M. catarrhalis was identified and it was not associated with ATCase. These data support the reclassification of M. catarrhalis out of the Neisseriaceae family.
Date: May 1998
Creator: Fowler, Michael A. (Michael Allen), 1961-
Partner: UNT Libraries

Responses of Cultured Neuronal Networks to the Cannabinoid Mimetic Anandamide

Description: The effects of cannabinoid agonists on spontaneous neuronal network activity were characterized in murine spinal cord and auditory cortical cultures with multichannel extracellular recording using photoetched electrode arrays. Different cultures responded reproducibly with global decreases of spiking and bursting to anandamide and methanandamide, but each agonist showed unique minor effects on network activity. The two tissues responded in a tissue-specific manner. Spontaneous activity in spinal tissue was terminated by 1 μM anandamide and 6.1 μM methanandamide. Cortical activity ceased at 3.5 μM and 2.8 μM respectively. Irreversible cessation of activity was observed beyond 8 μM for both tissues and test substances. Palmitoylethanolamide, demonstrated that CB2 receptors were not present or not responsive. However, the data strongly suggested the presence of CB1 receptors.
Date: May 1998
Creator: Morefield, Samantha I. (Samantha Irene)
Partner: UNT Libraries

Dimensions of Quality : Teachers' Beliefs and Practices in Texas Public Prekindergartens

Description: This study explores beliefs and practices about standards of quality in Texas public prekindergartens as viewed from various perspectives, including prekindergarten teachers, administrators of prekindergarten programs, and families of prekindergarten students. These beliefs and practices are compared with widely-accepted national standards of quality for preschool programs.
Date: May 1998
Creator: Kelly, Katherine Taddie
Partner: UNT Libraries

A Program Evaluation Study of a Partial Hospital Program

Description: The purpose of the present study was to assess patient improvement in a specific freestanding partial hospital. Improvement was assessed in two specific areas: 1) symptom reduction as measured by the Symptom Check List-90-Revised (SCL-90-R) and 2) social adjustment as measured by the Social Adjustment Scale Self-Report (SAS-SR) at admission, discharge and three month follow-up. In addition, improvement was assessed from two perspectives: 1) patient evaluation and 2) therapist evaluation. Results indicated that there was statistically significant improvement from admission to discharge on the SCL-90-R and the SAS-SR. This improvement was maintained from discharge to three month follow-up. Findings also revealed statistically significant improvement when analyzed from both the patient perspective and the therapist perspective.
Date: May 1998
Creator: Damkroger, Mary Katherine
Partner: UNT Libraries

Stoichiometry and Deposition Temperature Dependence of the Microstructural and Electrical Properties of Barium Strontium Titanate Thin Films

Description: Barium Strontium Titanate (BST) was deposited on Pt/ZrO2 / SiO2/Si substrates using liquid source metal organic chemical vapor deposition. A stoichiometry series was deposited with various GrII/Ti ratios (0.658 to 1.022) and a temperature series was deposited at 550 to 700°C. The thin films were characterized using transmission electron microscopy. Both series of samples contained cubic perovskite BST and an amorphous phase. The grain size increased and the volume fraction of amorphous phase decreased with increasing deposition temperature. The electrical and microstructural properties improved as the GrII/Ti ratio approached 1 and deteriorated beyond 1. This research demonstrates that BST thin films are a strong candidate for future MOS transistor gate insulator applications.
Date: May 1998
Creator: Pena, Piedad
Partner: UNT Libraries

Studies in Bank Contagion: Three Regulatory Events

Description: This research describes an analysis, using event-study methodology, of the reaction of the stock returns of a sample, drawn from the one-hundred largest bank holding companies, to certain actions of regulatory agencies. The first part of the analysis examines the reaction of the bank stocks to the closure of the Bank of New England, using cross-sectional variables not previously examined by other investigators. The second event considers the invalidation of interest-rate swap contracts by the British Law Lords, the highest court in Britain. The third case is an examination of the effects of actions taken to enforce the Community Reinvestment Act. All three events have significant abnormal returns in at least one sub-sample and event window. The results of the cross-sectional analysis and the lack of response to later events are consistent with market efficiency in the semi-strong form. The results are also consistent with the hypothesis that regulatory policies that emphasize consistency and banking system safety are desirable.
Date: May 1998
Creator: Springstube, Woodard R. (Woodard Rex)
Partner: UNT Libraries

Gender Differences Associated with Enrollment in the Texas Academy of Mathematics and Science

Description: This study sought to determine if different factors had influenced females and males to select engineering/science-related studies at the Texas Academy of Mathematics and Science (TAMS). The data were collected in the fall semester in 1997 at TAMS located on the University of North Texas campus from a survey of factors reported in the literature that had influenced students to enroll in engineering/science-related curriculum.
Date: May 1998
Creator: Burns, Robert T. (Robert Thomas), 1942-
Partner: UNT Libraries