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Analysis of Thermoplastic Polyimide + Polymer Liquid Crystal Blends (open access)

Analysis of Thermoplastic Polyimide + Polymer Liquid Crystal Blends

Thermoplastic polyimides (TPIs) exhibit high glass transition temperatures (Tgs), which make them useful in high performance applications. Amorphous and semicrystalline TPIs show sub-Tg relaxations, which can aid in improving strength characteristics through energy absorption. The a relaxation of both types of TPIs indicates a cooperative nature. The semicrystalline TPI shows thermo-irreversible cold crystallization phenomenon. The polymer liquid crystal (PLC) used in the blends is thermotropic and with longitudinal molecular structure. The small heat capacity change (ACP) associated with the glass transition indicates the PLC to be rigid rod in nature. The PLC shows a small endotherm associated with the melting. The addition of PLC to the semicrystalline TPI does not significantly affect the Tg or the melting point (Tm). The cold crystallization temperature (Tc) increases with the addition of the PLC, indicating channeling phenomenon. The addition of PLC also causes a negative deviation of the ACP, which is another evidence for channeling. The TPI, PLC and their blends show high thermal stability. The semicrystalline TPI absorbs moisture; this effect decreases with the addition of the PLC. The absorbed moisture does not show any effect on the degradation. The addition of PLC beyond 30 wt.% does not result in an improvement …
Date: May 1998
Creator: Gopalanarayanan, Bhaskar
System: The UNT Digital Library
Experimental and Theoretical Studies of Polycarbocyclic Compounds (open access)

Experimental and Theoretical Studies of Polycarbocyclic Compounds

Part I. Diels-Alder cycloadditions of 1,2,3,4,9,9-hexachloro-1α,4α,4aα,8aβ-tetrahydro-l,4-methanonaphthalene (32) and 1,2,3,4,9,9-hexachloro-lα,4α,6,7- tetrahydro-l,4-methanonaphthalene (33) to 4-methyl- and 4-phenyl-l,2,4-triazoline-3,5-dione [MTAD and PTAD, respectively] and to N-methylmaleimide (NMM) have been studied. The structures of several of the resulting cycloadducts were determined by X-ray crystallographic methods. The observed stereoselectivity of each of these Diels-Alder reactions was further investigated via application of theoretical methods. Thus, semiempirical (AMI) and ab initio molecular orbital calculations were used to calculate relative energies. Ab initio calculations were employed to perform frontier molecular orbital analyses of diene-dienophile interactions.
Date: May 1998
Creator: Shukla, Rajesh, 1964-
System: The UNT Digital Library
The Relationship between Parental Empathy and Parental Acceptance and the Effect of Filial Therapy Training on this Relationship (open access)

The Relationship between Parental Empathy and Parental Acceptance and the Effect of Filial Therapy Training on this Relationship

This study was conducted to determine the relationship between parental empathy (PE) and parental acceptance (PA) and the effect of filial therapy training (FTT) on this relationship. Filial therapy training is a parent education program in which the goal is the development of PE and PA. The Measurement of Empathy in Adult-Child Interaction (MEACI) and the Porter Parental Acceptance Scale (PPAS) are two widely used instruments in filial therapy studies to measure PE and PA, respectively. The purpose of this study was to determine the relationship between parental empathy and parental acceptance, and the effect of filial therapy training on this relationship. Specifically, this study was designed to investigate the correlations between the MEACI and the PPAS.
Date: May 1998
Creator: Poon, Wai-Chi Samuel
System: The UNT Digital Library
Quantum-Confined CdS Nanoparticles on DNA Templates (open access)

Quantum-Confined CdS Nanoparticles on DNA Templates

As electronic devices became smaller, interest in quantum-confined semiconductor nanostructures increased. Self-assembled mesoscale semiconductor structures of II-VI nanocrystals are an especially exciting subject because of their controllable band gap and unique photophysical properties. Several preparative methods to synthesize and control the sizes of the individual nanocrystallites and the electronic and optical properties have been intensively studied. Fabrication of patterned nanostructures composed of quantum-confined nanoparticles is the next step toward practical applications. We have developed an innovative method to fabricate diverse nanostructures which relies on the size and a shape of a chosen deoxyribonucleic acid (DNA) template.
Date: May 1998
Creator: Rho, Young Gyu
System: The UNT Digital Library
Interactions of Clean and Sulfur-modified Reactive Metal Surfaces with Aqueous Vapor and Liquid Environments : A Combined Ultra-high Vacuum/electrochemistry Study (open access)

Interactions of Clean and Sulfur-modified Reactive Metal Surfaces with Aqueous Vapor and Liquid Environments : A Combined Ultra-high Vacuum/electrochemistry Study

The focus of this research is to explore the molecular-level interactions between reactive metal surfaces and aqueous environments by combined ultra-high vacuum/electrochemistry (UHV-EC) methodology. The objectives of this work are to understand (1) the effects of sulfate ions on the passivity of metal oxide/hydroxide surface layer, (2) the effects of sulfur-modification on the evolution of metal oxide/hydroxide surface layer, and (3) the effects of sulfur adsorbate on cation adsorption at metal surfaces.
Date: May 1998
Creator: Lin, Tien-Chih, 1966-
System: The UNT Digital Library
Studies in Bank Contagion: Three Regulatory Events (open access)

Studies in Bank Contagion: Three Regulatory Events

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)
System: The UNT Digital Library
Convergence of Self and Other Ratings of Personality: a Structural Equation Analysis (open access)

Convergence of Self and Other Ratings of Personality: a Structural Equation Analysis

Recently, multi-source feedback has been a popular way of providing performance-related feedback to individuals in many organizations. Many who use multi-source feedback consider Rating Convergence, others seeing target individuals as they see themselves, to be a positive outcome of this process. However, the variables that account for Rating Convergence are not known. This study investigated whether the personality factor Extroversion and Behavioral Consistency, acting as a moderator variable, could account for Self-other Rating Convergence, particularly the Convergence between self and peer Ratings. The sample consisted of 235 mid-level managers from a variety of industries who were participants in individual career development workshops. Using structural equation modeling, the results indicated that a model consisting of a single Extroversion factor could account for the convergence of self-peer ratings. This finding calls into question the significance of Rating Convergence when using multi-source rating instruments that provide feedback on trait characteristics since it may be heavily influenced by a single personality factor rather than observers' comprehensive understanding of the ratee's performance.
Date: May 1998
Creator: McElhenie, Michael K. (Michael Keith)
System: The UNT Digital Library
The Role and Functions of Diversity Affairs Centers' Chief Personnel Officers at Public Universities in Texas (open access)

The Role and Functions of Diversity Affairs Centers' Chief Personnel Officers at Public Universities in Texas

The problem of this study concerns the role and functions of diversity affairs centers' chief personnel officers at public universities in Texas. Because of the political and evolving nature of diversity affairs offices, it is important to understand the functions and types of services these centers provide with respect to institutional goals, missions, and student retention at public universities in Texas.
Date: May 1998
Creator: David, John Seh
System: The UNT Digital Library
The Effects of Parental Divorce and Family Conflict on Young Adults Females' Perceptions of Social Support and Adjustment (open access)

The Effects of Parental Divorce and Family Conflict on Young Adults Females' Perceptions of Social Support and Adjustment

The purpose of this study was to explore the effects of parental divorce and family conflict during adolescence on young adult females' social support and psychological adjustment. The three areas explored were perceptions of relationship satisfaction and closeness, sources and amount of social support and adjustment. One hundred and forty-one female undergraduates, 53% from families in which their parents are still married and 47% from families in which a parental divorce occurred during adolescence, completed the following measures: the Dyadic Adjustment Scale (Spanier, 1976), the Social Provisions Scale-Source Specific (Cutrona, 1989), the Inventory of Common Problems (Hoffman & Weiss, 1986), the Family Environment Scale (Moos & Moos, 1981), and the Sibling Relationship Questionnaire (Furman & Buhrmester, 1985).
Date: May 1998
Creator: Quinn, M. Theresa
System: The UNT Digital Library
Effects of a Technology Enriched Learning Environment on Student Development of Higher Order Thinking Skills (open access)

Effects of a Technology Enriched Learning Environment on Student Development of Higher Order Thinking Skills

The problem for this study was to enhance the development of higher order thinking skills and improve attitudes toward computers for fifth and sixth grade students. The purpose of this study was to determine the impact of a Technology Enriched Classroom on student development of higher order thinking skills and student attitudes toward the computer. A sample of 80 sixth grade and 86 fifth grade students was tested using the Ross Test of Higher Cognitive Processes. The Ross Test was selected because of its stated purpose to judge the effectiveness of curricula or instructional methodology designed to teach the higher-order thinking skills of analysis, synthesis and evaluation as defined by Bloom. The test consisted of 105 items grouped into seven subsections. In addition, the students were surveyed using the Computer Attitude Questionnaire developed by the Texas Center for Educational Technology. The questionnaire assessed sixty-five questions combined to measure eight attitudes.
Date: May 1998
Creator: Hopson, Michael H. (Michael Hugh)
System: The UNT Digital Library
Mandatory Continuing Education in Nursing: a Texas Perspective (open access)

Mandatory Continuing Education in Nursing: a Texas Perspective

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
System: The UNT Digital Library
Matador (open access)

Matador

Matador is an opera scored for orchestra, mixed chorus and soloists (mezzosoprano, 3 tenors, 2 baritones). The work is in one act divided into two main sections. Each of these sections is divided into subsections. The libretto is aphoristic in nature and dictates the form of each of these subsections. The division into two parts also serves as a means to evoke a sense of hopelessness of emotions in the first and a transforming disposition that culminates in a jubilant song in the second.
Date: May 1998
Creator: Patino, Julio
System: The UNT Digital Library
The Effect of Giving Class Time for Reading on the Reading Achievement of Fourth Graders and the Effect of Using a Computer-Based Reading Management Program on the Reading Achievement of Fifth Graders (open access)

The Effect of Giving Class Time for Reading on the Reading Achievement of Fourth Graders and the Effect of Using a Computer-Based Reading Management Program on the Reading Achievement of Fifth Graders

This study investigated the problem that educators have throughout the state of Texas. The problem educators have is that reading scores continue to fall short of state expectations. This study investigated the effectiveness of 90 minutes of class time given for reading to students who use the Electronic Bookshelf Program and the effectiveness of the Electronic Bookshelf Program, which is being sold to school districts throughout the nation. The literature review focused on the effectiveness of independent reading on reading achievement, and the effectiveness of using computer-based reading programs to increase reading achievement.
Date: May 1998
Creator: Peters, Rochelle
System: The UNT Digital Library
A Longitudinal Study of Graduation, Retention, and School Dropout for Students in Regular and Special Education (open access)

A Longitudinal Study of Graduation, Retention, and School Dropout for Students in Regular and Special Education

This study examined differences in retention, graduation, and dropout between students in grades 9-12 in special education and regular education in the state of Texas for school years 1992-93 through 1995-96. The purpose was to gather information regarding the possible adverse effects of increased academic standards and mandatory testing on students with disabilities. The results indicate that when compared to students in regular education, students with disabilities are significantly more likely to be retained and are not experiencing the same decline in dropout rates as regular students. There is no indication that students with disabilities have been adversely affected by school reform but the size of the school district may play a significant role in whether or not students with disabilities dropout of school.
Date: May 1998
Creator: Smith, Karen S., 1948-
System: The UNT Digital Library
Scanning Tunneling Microscopy of Epitaxial Diamond (110) and (111) Films and Field Emission Properties of Diamond Coated Molybdenum Microtips (open access)

Scanning Tunneling Microscopy of Epitaxial Diamond (110) and (111) Films and Field Emission Properties of Diamond Coated Molybdenum Microtips

The growth mechanism of chemical vapor deposition (CVD) grown homo-epitaxial diamond (110) and (111) films was studied using ultrahigh vacuum (UHV) scanning tunneling microscopy (STM). In addition, the field emission properties of diamond coated molybdenum microtips were studied as a function of exposure to different gases.
Date: May 1998
Creator: Lim, Seong-Chu
System: The UNT Digital Library
Gender Differences Associated with Enrollment in the Texas Academy of Mathematics and Science (open access)

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

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-
System: The UNT Digital Library
Shifts of Focus Among Dimensions of User Information Problems as Represented During Interactive Information Retrieval (open access)

Shifts of Focus Among Dimensions of User Information Problems as Represented During Interactive Information Retrieval

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. This project extends research on interactive information retrieval, and presents a theoretical framework that synthesizes rational and non-rational questions concerning mental representation as it pertains to user's understanding of information problems.
Date: May 1998
Creator: Robins, David B. (David Bruce)
System: The UNT Digital Library
Social Exchange Under Fire: Direct and Moderated Effects of Job Insecurity on Social Exchange (open access)

Social Exchange Under Fire: Direct and Moderated Effects of Job Insecurity on Social Exchange

This study is concerned with the impact of job insecurity on the vital social exchange relationship between employee and employer. Specifically, it explored the relationship between job insecurity and two important social exchange outcomes—organizational commitment and organizational citizenship behavior. Moreover, it assessed the moderating effects of individual factors (communal orientation and powerlessness) and situational factors (trust in management, procedural fairness, and organizational support) on these relationships.
Date: May 1998
Creator: Bultena, Charles D. (Charles Dean)
System: The UNT Digital Library
The Awareness and Perception of Distance Education by the Leadership in the Texas State Technical College System (open access)

The Awareness and Perception of Distance Education by the Leadership in the Texas State Technical College System

The purpose of this study was to determine whether there were differences in the levels of awareness and perception concerning distance education among the leadership at the seven campuses of the Texas State Technical College (TSTC) System.
Date: May 1998
Creator: Knue, John Raymond
System: The UNT Digital Library
A Quenchofluorometric Study of Polycyclic Aromatic Hydrocarbons in Molecularly Organized Media (open access)

A Quenchofluorometric Study of Polycyclic Aromatic Hydrocarbons in Molecularly Organized Media

Detection, identification and separation of polycyclic aromatic compounds in environmental samples are of extreme importance since many of these compounds are well known for their potential carcinogenic and/or mutagenic activities. Selective quenching of molecular fluorescence can be utilized effectively to analyze mixtures containing different polycyclic aromatic hydrocarbons. Molecularly organized assemblies are used widely in detection and separation of these compounds mainly because of less toxicity and enhanced solubilization capabilities associated with these media. Feasibility of using nitromethane and the alkylpyridinium cation as selective fluorescence quenching agents for discriminating between alternant versus nonalternant polycyclic aromatic hydrocarbons (PAHs) is critically examined in several molecularly organized micellar solvent media. Fluorescence quenching is used to probe the structural features in mixed micelles containing the various combinations of anionic, cationic, nonionic and zwitterionic surfactants. Experimental results provide valuable information regarding molecular interactions between the dissimilar surfactants.
Date: May 1998
Creator: Pandey, Siddharth
System: The UNT Digital Library
Boulez's Sonatine and the Genesis of His Twelve-tone Practice (open access)

Boulez's Sonatine and the Genesis of His Twelve-tone Practice

This dissertation proposes that the Sonatine broadly unfolds a kinetic structure that stems from the traditional tension-relief model and, consequently, its dependence on tradition proves much deeper than Boulez would acknowledge.
Date: May 1998
Creator: Chang, Sangtae
System: The UNT Digital Library
Thermodynamic and Structural Studies of Layered Double Hydroxides (open access)

Thermodynamic and Structural Studies of Layered Double Hydroxides

The preparation of layered double hydroxides via titration with sodium hydroxide was thoroughly investigated for a number of M(II)/M(III) combinations. These titration curves were examined and used to calculate nominal solubility product constants and other thermodynamic quantities for the various LDH chloride systems.
Date: May 1998
Creator: Boclair, Joseph W. (Joseph Walter)
System: The UNT Digital Library
Technology Infusion in Career Services at U.S. Institutions of Higher Education in the Southwest (open access)

Technology Infusion in Career Services at U.S. Institutions of Higher Education in the Southwest

The purpose of this study was to examine the use of computer and communications technologies at four-year public/private college and university career centers that are members of the Southwest Association of Colleges and Employers (SWACE). The findings of this study reveal that (a) all career centers are now using computer and telecommunications technologies for at least one office function; (b) small institutions do not use technologies as much as large institutions because they have fewer financial resources, less technical support from institutions, fewer personnel, and they also need time to learn to use technologies effectively; (c) public career centers are more willing to explore new technologies but private career centers mostly adopt and implement proven technologies; (d) career education does not utilize technologies as much as career counseling or job placement functions; (e) lack of financial resources and lack of technical support are major barriers to a technological infusion; and (f) technologies, including electronic student databases, computerized presentations with the network connection, and OCR scanners, will be needed in the near future.
Date: May 1998
Creator: Charoensri, Pijarn
System: The UNT Digital Library
An Investigation of Personal Investment Levels Among Nonmusic Major Piano Students Using Portfolio Assessment (open access)

An Investigation of Personal Investment Levels Among Nonmusic Major Piano Students Using Portfolio Assessment

The purpose of this study was to compare personal investment levels among nonmusic major piano students in the contexts of portfolio and teacher-directed assessment. Three problems were addressed: 1) identifying students' perceptions of direction, persistence, continuing motivation, intensity, and performance in the context of teacher-directed goal setting, choice of instructional activities, and evaluation of performance; 2) identifying students' perceptions of the five personal investment behaviors in the context of portfolio assessment; and 3) comparing student perceptions as identified in problems one and two.
Date: May 1998
Creator: Heisler, Paul K.
System: The UNT Digital Library