UNT Theses and Dissertations - 191 Matching Results

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A Study of the Processing Properties of Hard-Particle Reinforced Composite Solders

Description: The microstructural, mechanical and thermal properties of various composite solder formulations were investigated. Special interest was given in observing the processing properties, microstructural characteristics, fatigue behavior, tensile strength, and the effect of environmental ageing on the composite solder formulations. The solderability parameters wetting and speed of soldering, reflow temperature, and the thermal stability of the resulting composite solder were also examined.
Date: May 1994
Creator: Calderon, Jose Guadalupe
Partner: UNT Libraries

Substitution Chemistry of the Cobalt Complexes [Co₂(CO)₆(PhC≡CR) (R=Ph, H) and PhCCo₃(CO)₉] with the Diphosphine Ligands [Bis(diphenylphosphino)maleic Anhydride (BMA) and (Z)-Ph₂PCH=CHPPh₂]. Reversible Chelate-to-Bridge Diphosphine Ligand Exchange, Phosphorus-Carbon Bond Cleavage and Phosphorus-Carbon Bond Formation

Description: The tricobalt cluster PhCCo3(CO)9 (1) reacts with the bidentate phosphine ligand 2,3-bis(diphenylphosphino)maleic anhydride (bma) in the presence of added Me3NO to give the diphosphine-substituted cluster PhCCo3(CO)7(bma) (2). Cluster 2 is unstable in solution, readily losing CO to afford Co3(CO)6[(μ2-η2/η1-C(Ph)C=C(PPh2)C(O)OC(O)](μ2-PPh2) (3) as the sole observed product. VT-31P NMR measurements on cluster 2 indicate that the bma ligand functions as both a chelating and a bridging ligand. At -97 °C, 31P NMR analysis of 2 reveals a Keq of 5.7 in favor of the bridging isomer. The bridged bma cluster 2 is the only observed species above -50°C. The solid-state structure of 2 does not correspond to the major bridging isomer observed in solution but rather the minor chelating isomer. The conversion of 2 to 3 followed first-order kinetics, with the reaction rates being independent of the nature of the reaction solvent and strongly suppressed by added CO, supporting a dissociative loss of CO as the rate-determining step. The activation parameters for CO loss were determined to be ΔH≠ = 29.9 ± 2.2 kcal/mol and ΔS≠ = 21.6 ± 6 eu.
Date: December 1994
Creator: Yang, Kaiyuan
Partner: UNT Libraries

Symphony in Three Movements

Description: Symphony in Three movements is an orchestra work scored for two flutes, two oboes, two clarinets in Bb, two bassoons, two horns in F, three trumpets in Bb, three trombones, one tuba, percussion and strings. The percussion consists of timpani, vibraphone, temple block, tom-tom, suspended cymble, bass drum, and gong. The piece is not based on any non-musical image. The three movements of this work, I.(variation-like) II.(ternary) III.(fantasia-like), are based on the combination of the solemn ceremonial atmosphere of Korean music and early twentieth-century Western music.
Date: December 1994
Creator: Park, Ki-Seob
Partner: UNT Libraries

The Synthesis and Chemistry of Polyciclic Cage Compounds

Description: Chapter I describes the synthesis of a trishomocubyl helical tubuland diol and some aspects of its inclusion chemistry. Thus, all three isomers of 4,7-dimethylpentacyclo[6.3.0.0^2,6.0^3,10.0^5,9]undecane-4,7-diol have been prepared and their X-ray structures have been determined. The syn,syn-isomer crystallizes in a double-stranded hydrogen-bonded lattice, while anti,syn-isomer forms a hydrogen-bonded layer lattice. In contrast, the anti,anti-isomer is a new member of the helical tubuland diol host family; its crystal lattice consists of parallel canals with a trefoil-shaped cross-section of area 25.4 Å^2. Chapter II describes the synthesis of new molecular clefts. These molecular clefts have been synthesized via base-promoted reactions of 3,6-diaryl-l,2,4,5-tetrazines with tetracyclo[6.3.0.0^4,11.0^5,9]undecane-3,6-dione and with tricyclo[6.3.0.0^2,6]undecane-3,11-dione, respectively. Compounds of this type are of interest as a potential new class of host molecules for use in host-guest complexation studies. Chapter III reports the synthesis of stereospecifically deuterated spiro(oxetane-3,8'-pentacyclo[5.4.0.0^2,6.0^3,10.0^5,9]undecanes) and their acid-promoted ring opening and concomitant rearrangements. The deuterium-containing reaction products have been characterized via analysis of their NMR and mass spectra. The results strongly suggest that intramolecular 1,5-hydride shifts provide an important pathway through which the acid promoted rearrangements occur. Chapter IV reports the oxidation of heptacyclo-[6.6.0.0^2,6.0^3,13.0^4,11.0^5,9.0^10,14] tetradecane (HCTD) via application of Barton's "GoAgg" systems. The products have been characterized by NMR and mass spectral analysis. Under GoAgg^v conditions, oxidation of HCTD proceeds to afford heptacyclo [6.6.0.0^2,6.0^3,13.0^4,11.0^5,9.0^10,14]tetradecan-7-one in 1% yield.
Date: December 1994
Creator: Wang, Yanjun
Partner: UNT Libraries

Teacher perceptions and applications of the Texas Assessment of Academic Skills (TAAS) in the seventh-grade social studies curriculum

Description: This investigation sought to determine how seventh-grade social studies teachers perceive TAAS objectives for social studies, language arts, and mathematics, and how they apply them in the classroom. A detailed questionnaire was submitted to fifty teachers in the Dallas metropolitan area; a 72 percent return was received.
Date: August 1994
Creator: Harmon, Larry G.
Partner: UNT Libraries

A Theoretical Model of Technical Professionals in Work Teams

Description: The purpose of this research project was to develop and test a theoretical model of technical professionals in self-managing work teams using a number of constructs that have not been tested with this population. The overall aim was to begin to humbly fill a significant gap in the research literature focused on self-managing work teams. The rationale for the need to address technical professional perspectives in team settings is discussed in the following section.
Date: December 1994
Creator: Beyerlein, Susan T.
Partner: UNT Libraries

A Theory of the Role of Medium of Exchange in Mergers and Acquisitions

Description: An acquisition bid is like any other proposal for risky investment. The difference arises due to additional source of risk arising from two different sources of information asymmetry due to private knowledge held by the bidder and target. We hypothesize that the bidding process evolves in a manner to optimize bidder's investment in the target through a process of joint signalling. Medium of exchange and bid premium are used as the two signal elements simultaneously by the bidder. We develop a multiple signalling model of the bidding process which is fully revealing in equilibrium.
Date: May 1994
Creator: Tiwari, Rajesh Kumar
Partner: UNT Libraries

Thermophysical and Mechanical Properties of Polymer Liquid Crystals and Their Blends

Description: Tensile properties, namely the elastic modulus, tensile strength, percent of elongation at yield and at the break were determined for the pure components and blends. The results are connected to the respective phase diagrams and demonstrate that blending makes property manipulation possible. Blends for which the mechanical properties are better than those of pure EPs can be obtained.
Date: May 1994
Creator: López, Betty Lucy
Partner: UNT Libraries

The Ties that Bind : Breaking the Bonds of Victimization in the Novels of Barbara Pym, Fay Weldon and Margaret Atwood

Description: In this study of several novels each by Barbara Pym, Fay Weldon, and Margaret Atwood, I focus on two areas: the ways in which female protagonists break out of their victimization by individuals, by institutions, and by cultural tradition, and the ways in which each author uses a structural pattern in her novels to propel her characters to solve their dilemmas to the best of their abilities and according to each woman's personality and strengths.
Date: December 1994
Creator: Rathburn, Fran M. (Frances Margaret), 1948-
Partner: UNT Libraries

Transport Processes in Synchrotrons

Description: This thesis examines the evolution of beams in synchrotrons. Following an introduction to accelerator physics in Chapter 1, in Chapter 2 I describe the Fermilab E778 'diffusion' experiment. Families of sextupoles were powered to drive the 2/5 resonance, and a beam was then kicked to populate a nonlinear region of the transverse phase space. The beam was then observed over periods of approximately 30 minutes for a variety of kick amplitudes and physical apertures. In Chapter 3 comments about the analytic treatment of such systems are discussed, including the assumptions inherent in the conventional treatment. I motivate my use of a simplified model in Chapter 4 after examining common computational methods. Deriving the model from the formalism of traditional accelerator physics, I discuss its implementation on a massively parallel computer, the Intel iPSC/860 hypercube, and examine the performance of this algorithm in detail. Using the simple model to perform the numerical experiment equivalent to E778 is the subject of Chapter 5. I derive the parameters needed for the simple model based upon the physical experiment. Both three dimensional cases and cases with reduced dimensionality are run. From power supply ripple data and an electrical model of the magnet string, I compute tune modulation depths, and a subset of these are run. I conclude that tune modulation from power supply ripple is not a significant source of transport for this system. In Chapter 6, the intensities of the beams are used to compare the experimental and numerical runs, using both exponential and algebraic decays, and the algebraic form is seen to provide a better fit. The agreement between numerical and experimental results is best for fully three-dimensional runs, but the numerical results show slower decay than the experimental. Individual particles are examined, whose motion consists of stochastic motion interspersed with regular ...
Date: May 1994
Creator: Cole, Benjamin H. (Benjamin Holland)
Partner: UNT Libraries

The Trumpet in Selected Solo and Chamber Works of Paul Hindemith : Elements of Trumpet Technique and Their Relationship to the Gebrauchsmusik Concept, a Lecture Recital, Together with Three Recitals of Selected Works of J.N. Hummel, A. Jolivet, C. Chaynes, and Others

Description: The trumpet was one of the wind instruments Hindemith used frequently in his chamber music, and he employed it prominently in five works from 1925 to 1954. These works are the Sonate fur Trompete (1939), the Konzert fur Trompete in B und Fagott mit Streichorchester (1954), Drei Stucke (19251 the Septett fur Blasinstrumente (1949), and "Morgenmusik," from the collection Plöner Musiktag (1932). This study examines and compares Hindemith's writing for the trumpet in these selected works, noting features in his use of the instrument which determine the applicability of the works to the Gebrauchsmusik concept.
Date: August 1994
Creator: Bogard, Rick
Partner: UNT Libraries

The Undergraduate Teaching of Archetypal Patterns in the Writings of Alice Walker

Description: Significant passages in Alice Walker's writings give evidence of archetypal patterns from Carl Jung and feminine archetypal patterns from Annis Pratt. Since a knowledge of archetypal patterns can influence the total understanding of aspects of Walker's writings, a study of these patterns in the undergraduate classroom benefits the student and opens up another system of analyzing writings, particularly writings by African-American women.
Date: May 1994
Creator: Linn, Linda S. (Linda Salmon)
Partner: UNT Libraries

The Use of Nonfiction/Informational Trade Books in an Elementary Classroom

Description: The purpose of the study was to describe the use of nonfiction/informational trade books within a literature-based elementary classroom by students and the teacher. Using a qualitative ethnographic approach, the researcher became a participant observer in a third grade classroom during a two and one-half week thematic unit about the westward movement. Data were collected from field notes, audiotapes of class discussions and informal interviews, documents of students' work, photographs, daily observer comment summaries, and memos. These data were coded, analyzed for recurring patterns, and grouped together, resulting in grounded theory.
Date: August 1994
Creator: Briggs, Connie Craft
Partner: UNT Libraries

Using Steepest Descent to Find Energy-Minimizing Maps Satisfying Nonlinear Constraints

Description: The method of steepest descent is applied to a nonlinearly constrained optimization problem which arises in the study of liquid crystals. Let Ω denote the region bounded by two coaxial cylinders of height 1 with the outer cylinder having radius 1 and the inner having radius ρ. The problem is to find a mapping, u, from Ω into R^3 which agrees with a given function v on the surfaces of the cylinders and minimizes the energy function over the set of functions in the Sobolev space H^(1,2)(Ω; R^3) having norm 1 almost everywhere. In the variational formulation, the norm 1 condition is emulated by a constraint function B. The direction of descent studied here is given by a projected gradient, called a B-gradient, which involves the projection of a Sobolev gradient onto the tangent space for B. A numerical implementation of the algorithm, the results of which agree with the theoretical results and which is independent of any strong properties of the domain, is described. In chapter 2, the Sobolev space setting and a significant projection in the theory of Sobolev gradients are discussed. The variational formulation is introduced in Chapter 3, where the issues of differentiability and existence of gradients are explored. A theorem relating the B-gradient to the theory of Lagrange multipliers is stated as well. Basic theorems regarding the continuous steepest descent given by the Sobolev and B-gradients are stated in Chapter 4, and conditions for convergence in the application to the liquid crystal problem are given as well. Finally, in Chapter 5, the algorithm is described and numerical results are examined.
Date: August 1994
Creator: Garza, Javier, 1965-
Partner: UNT Libraries

Values, Beliefs, and Characteristics of Hispanic Students at One Urban Southwestern University

Description: The problem of this study concerns the values, beliefs, and characteristics of Hispanic students attending a large urban southwestern university. The study is qualitative and utilizes the constant comparative research method. Data is gathered from interviews with 21 Hispanic students, campus surveys, university records, a census report, and observation of campus activities. The literature review spans organizational culture, campus culture and subcultures, as well as studies regarding Hispanic students. The findings introduce the students and report their perspectives in both their own words and in summarized themes for each research question. In summary, Hispanic students and their college experiences are diverse. They major in a wide range of disciplines, come from varying socio-economic households, have parents with varying levels of education, are surprised by various aspects of college, and they do not all speak Spanish.
Date: May 1994
Creator: Gaede, Laurelyn I. (Laurelyn Irving)
Partner: UNT Libraries

Vincent Ludwig Persichetti's Parable for Solo Flute (Alto or Regular): A Study of Its Compositional Elements: Together with Recitals of Selected Works of Beethoven, Devienne, Handel, Hummel, Kreutzer, and Others

Description: This dissertation focuses on the first Parable of Vincent Ludwig Persichetti, written for alto flute in 1965. Persichetti spent from 1965 to 1986 (almost the last twenty years of his life) composing twenty-four additional Parables for various solo instruments, instrumental combinations, and even one in the form of an opera.
Date: December 1994
Creator: Zoloth, Alan Gary
Partner: UNT Libraries

Violent and Nonviolent Juvenile Offenders : An Assessment of Differences in Object Relations Functioning Using the Thematic Apperception Test

Description: TAT stories and demographic information of 30 violent and 30 nonviolent juvenile delinquents were obtained. Institutional assessment records at Dallas County Juvenile Department (DCJD) served as the data base for this study. TAT stories and demographic information of 30 violent and 30 nonviolent juvenile delinquents were obtained. Institutional assessment records at Dallas County Juvenile Department (DCJD) served as the data base for this study. Differences with respect to object relations functioning between juveniles charged with two categories of index offenses: property offenses and aggravated assault were examined. Object relations were assessed utilizing a scoring system designed for use with the Thematic Apperception Test (TAT). The scoring system encompasses a psychoanalytic perspective and consists of four dimensions representing separate but interrelated aspects of object relations. It was hypothesized that juvenile delinquents who commit violent crimes would exhibit lower object relations functioning as compared to juvenile delinquents who commit nonviolent crimes.
Date: December 1994
Creator: Cox, Randall J. (Randall Judd)
Partner: UNT Libraries

Vocal Self-identification, Singing Style, and Singing Range in Relationship to a Measure of Cultural Mistrust in African-American Adolescent Females

Description: The purpose was to determine the relationship between high or low cultural mistrust and vocal characteristics in African-American adolescent females. The vocal characteristics were vocal self-identification, singing style, and singing range.
Date: May 1994
Creator: Johnson, Beverly Yvonne
Partner: UNT Libraries

The Wealth Effect of the Risk-Based Capital Regulation on the Commercial Banking Industry

Description: The purpose of this study is to examine the wealth effect of the Risk-Based Capital (RBC) regulation on the U.S. commercial banking industry. The RBC plan was first proposed in January 1986, and its final form was announced on July 11, 1988. This plan resulted from dissatisfaction with the old capital regulation, which did not account for asset risk and off-balance sheet activities. The present study hypothesizes that the new regulation restricted bank optimal behavior and, therefore, adversely affected stock prices. The second and third hypotheses suggest that investors used company specific information, Net Tier 1 and Total risk-based capital ratios respectively, in valuing stocks of the affected bank holding companies. Hypotheses four and five suggest that abnormal returns are proportionally related to the levels of Net Tier 1 or Total RBC ratio. Both the traditional event study and the portfolio time-series regression, with RBC ratios (Net Tier 1 or Total) as the weight factors, are used in this study.
Date: August 1994
Creator: Zoubi, Marwan M. Sharif (Marwan Mohd Sharif)
Partner: UNT Libraries