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  Partner: UNT Libraries
 Decade: 1990-1999
 Year: 1998
 Collection: UNT Theses and Dissertations
Analyses of Particulate Contaminants in Semiconductor Processing Fluids

Analyses of Particulate Contaminants in Semiconductor Processing Fluids

Date: August 1998
Creator: Xu, Daxue
Description: Particle contamination control is a critical issue for the semiconductor industry. In the near future, this industry will be concerned with the chemical identities of contaminant particles as small as 0.01 pm in size. Therefore, analytical techniques with both high chemical sensitivity and spatial resolution are required. Transmission electron microscopy (TEM) provides excellent spatial resolution and yields structural and compositional information. It is rarely used, however, due to the difficulty of sample preparation. The goals of this research are to promote the use of TEM as an ultrafine particle analysis tool by developing new sample preparation methods, and to exploit the new TEM techniques for analysis of particles in semiconductor processing fluids. A TEM methodology for the analysis of particulate contaminants in fluids with an elemental detectability limit as low as 0.1 part per trillion (ppt), and a particle concentration detectability limit as low as 1 particle/ml for particles greater than 0.2 pm was developed and successfully applied to the analysis of particles in HF, H202, de-ionized (DI) water, and on the surface of an electronic device. HF samples from three manufacturers were examined. For HF (B), the maximum particle concentration was 8.3 x 103 particles/ml. Both a viscous material ...
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Biogeographic Relationships of Pocket Gophers (Geomys breviceps and Geomys bursarius) in the Southeastern Portion of Their Ranges

Biogeographic Relationships of Pocket Gophers (Geomys breviceps and Geomys bursarius) in the Southeastern Portion of Their Ranges

Date: August 1998
Creator: Elrod, Douglas Allen
Description: This research utilized population genetic analyses (protein starch-gel electrophoresis and DNA sequencing of the cytochrome b mtDNA gene), host-parasite specificity (lice coevolution), remote sensing of satellite data, and geographic information systems (GIS) to characterize newly discovered populations of pocket gophers (genus: Geomys) in Arkansas. These populations are isolated and occur in seemingly unsuitable habitat in the Ozark Mountains of Arkansas. Analyses of electrophoretic and ectoparasite data suggested the populations in the Ozark Mountains represented isolates allied to Geomys bursarius, a species not known to occur in Arkansas. Comparison of mitochondrial DNA sequence data of the cytochrome b gene with that of other taxa and morphometric analyses confirmed that these populations are most closely allied to G. bursarius occurring to the north in Missouri. Moreover, these mtDNA sequence analyses indicated a degree of differentiation typical of that between other subspecies of pocket gophers. Therefore, these populations represent a distinct genetic entity in an intermediate stage of speciation and should be designated as a new subspecies, Geomys bursarius ozarkensis. Molecular clock analysis revealed a time of lineage divergence for this new subspecies as approximately 511,000 YBP. Due to the isolated nature and limited distribution of this subspecies, an evaluation of critical habitat ...
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Dalbergia and Albizia: Plantlet Production via Tissue Culture, Karyological Evaluation, and Seed Anatomy with Scanning Electron Microscopy

Dalbergia and Albizia: Plantlet Production via Tissue Culture, Karyological Evaluation, and Seed Anatomy with Scanning Electron Microscopy

Date: December 1998
Creator: Ghosh, Nabarun
Description: A publication by the National Academy of Sciences, USA (1979) outlined some of the research need for a great variety of economically important woody species whose remaining genetic resources need urgently to be collected and conserved. A viable regeneration system was established via tissue and cell suspension culture for Albizia falcataria and A. lebbeck, two important wood yielding leguminous tree species. The culture medium was standardized after several trials to obtain callus from the leaflet explants of these two tree species. The optimum use of casein hydrolysate (w/v) and coconut milk (v/v) in addition to 6-Benzylaminopurine and Indole-3-butyric acid could induce morphogenesis and somatic embryogenesis in the cultured tissue. This reports the first observation on somatic embryogenesis ofA. lebbeck using leaflets as the explants. Scanning Electron Microscopy and histological studies were done on the different stages plant development following standard techniques. Embryogenesis in suspension culture followed regeneration of plantlets in A. lebbeck. In A.falcaaria the regenerative process followed via organogenesis from the shoot buds developed on the leaf explants. After hardening the regenerated plants were transferred to the greenhouse. Some of the trees grew more than 25 feet tall within a few months outside the greenhouse. Karyotype of the three ...
Contributing Partner: UNT Libraries
Role of α-Keto Acids In Cyanide Detoxification and Assimilation by Pseudomonas Bacteria

Role of α-Keto Acids In Cyanide Detoxification and Assimilation by Pseudomonas Bacteria

Date: December 1998
Creator: Pan, Guangliang
Description: Cyanide was rapidly removed when added to culture supernatants of seven different Pseudomonas. The ability to remove cyanide was correlated with the accumulation of α-keto acids (pyruvate and α-ketoglutarate). These compounds react with cyanide forming less toxic cyanohydrins, thus conferring a mechanism for bacterial cyanide tolerance. When added to growth media the α-keto acids were shown also to serve as effective cyanide antagonists. While all bacteria tested accumulated α-keto acids, only those capable of utilizing cyanide as a nutritional nitrogen source were able to metabolize cyanohydrins. In P. fluorescens NCIMB 11764, the same enzyme (cyanide oxygenase) shown previously to be involved in cyanide metabolism appears responsible for cyanohydrin transformation. Keto acid excretion is believed to represent a new mechanism of bacterial cyanide detoxification with further enzymatic metabolism of the cyanohydrins helping to explain how cyanide can satisfy the nitrogen requirement in cyanide-utilizing bacteria.
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Regulation of an S6/H4 Kinase in Crude Lymphosarcoma P1798 Preparations

Regulation of an S6/H4 Kinase in Crude Lymphosarcoma P1798 Preparations

Date: December 1998
Creator: Taylor, Allison Antoinette
Description: Purified S6/H4 kinase (Mr 60,000) requires autophosphorylation for activation. A rabbit anti-S6/H4 kinase peptide (SVIDPVPAPVGDSHVDGAAK) antibody recognized both the S6/H4 kinase holoenzyme and catalytic domain. Immunoreactivity with p60 kinase protein, and S6/H4 kinase activity were precisely correlated in fractions obtained from ion exchange chromatography of P1798 lymphosarcoma extracts. An enzyme which catalyzed the MgATP-dependent phosphorylation and activation of S6/H4 kinase coeluted with immunoreactivity from Mono 5, but not Mono Q chromatography. Since S6/H4 kinase is homologous with rac-activated PAK65, the observation that phosphorylation is also required for activation suggests a complex mechanism for in vivo activation of the S6/H4 kinase.
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Estimated Extent and Fate of Chlorinated Solvent Contamination in the Soil of the Naval Air Station, Dallas, Texas

Estimated Extent and Fate of Chlorinated Solvent Contamination in the Soil of the Naval Air Station, Dallas, Texas

Date: August 1998
Creator: Trescott, Jill V. (Jill Virginia)
Description: This thesis estimates the spatial extent of chlorinated solvent contamination of the soil at the Naval Air Station, Dallas, then estimates the fate and transport of these contaminants, over time, using the Soil Transport and Fate database and the Vadose-Zone Interactive Processes (VIP) modeling software. Geostatistical analysis identifies two areas with serious chlorinated solvent contamination. Fate and transport modeling estimates that this contamination will degrade and disperse from the soil phase to below regulatory limits within one year, although there is a risk of groundwater contamination. Contaminants are estimated to persist in the water and air phases of the soil. Further sampling is recommended to confirm the results of this study.
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Development of an In Vitro Protoplast Culture System for Albizia Lebek (L.) Benth., an Economically Important Leguminous Tree

Development of an In Vitro Protoplast Culture System for Albizia Lebek (L.) Benth., an Economically Important Leguminous Tree

Date: August 1998
Creator: Sinha, Debleena
Description: An in vitro system of generating protoplasts from their callus cultures was established. The friable callus was more productive in terms of producing protoplasts than the green compact callus. The concentration of the various cell wall degrading enzymes had an effect on the viability of the protoplasts in the medium. The protoplast system developed from the experiments was stable and could be used for the transformation experiments of Albizia lebek and for other plant improvement practices.
Contributing Partner: UNT Libraries
The Tent and its Contents: a Study of the Traditional Arts of Weaving by the Otaibah Tribe in Saudi Arabia

The Tent and its Contents: a Study of the Traditional Arts of Weaving by the Otaibah Tribe in Saudi Arabia

Date: December 1998
Creator: Alruwais, Bader A.
Description: This was an ethnographic study of the woven tent objects produced by the Bedouin Otaibah tribe in Najd, central Saudi Arabia; the study examines origin, techniques, character and significance of their weavings. A major objective of the researcher was to discern the relationship between the weavers' development of traditions and the factors of technique, medium and perceived meaning. The method used was investigative fieldwork that included techniques of face to face interviews and participant observation. Interviews with 50 Bedouin female weavers in Najd were conducted for 8 months. Background information on the Otaibah tribe and their traditional way of life was provided. The review of the literature of traditional arts, folk arts and art education illustrates that there is limited accessible information concerning the general history of traditional arts in Saudi Arabia. A discussion of the aesthetic value, definitions and roles of traditional art, tribal art and the differences between art and crafts was included. Analysis of data answered the study's questions through a presentation of the findings of the fieldwork. The Otaibah tribe has its own unique style of weaving. Information gathered from participant observation and documents from the Haifa Faisal Collection of Saudi Arabian Traditional Arts in Chicago ...
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Stoichiometry and Deposition Temperature Dependence  of the Microstructural and Electrical Properties of Barium Strontium Titanate Thin Films

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

Date: May 1998
Creator: Pena, Piedad
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.
Contributing Partner: UNT Libraries
Interactions of Clean and Sulfur-modified Reactive Metal Surfaces with Aqueous Vapor and Liquid Environments : A Combined Ultra-high Vacuum/electrochemistry Study

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

Date: May 1998
Creator: Lin, Tien-Chih, 1966-
Description: 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.
Contributing Partner: UNT Libraries
Masculine Role Conflict in Gay Men: Mediation of Psychological Well-Being and Help-Seeking Behaviors

Masculine Role Conflict in Gay Men: Mediation of Psychological Well-Being and Help-Seeking Behaviors

Date: August 1998
Creator: Simonsen, Gregory
Description: Gender role issues have been an integral part of psychology since the 1970s. More recently, theories and research have surfaced concerning the issues of maleness in our society. Most of these theories focus on masculine gender role and how it affects men in various ways, e.g., their psychological well-being, substance use, relational abilities, and help-seeking behaviors. One area of maleness that has consistently been left out of the Masculine Role Conflict (MRC) debate is that of homosexuality. As a gay man develops, he finds himself at odds with society over something that he experiences biologically as normal and appropriate. It is the contention of this paper that MRC is an issue related to psychological distress among gay men and not psychological weakness in gay men, per se.
Contributing Partner: UNT Libraries
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

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

Date: May 1998
Creator: Peters, Rochelle
Description: 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.
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Perceived Barriers to the Implementation of Site Based Management

Perceived Barriers to the Implementation of Site Based Management

Date: August 1998
Creator: Hancock, Don G. (Don Gaylon)
Description: The purpose of this study was to identify perceived barriers to the implementation of site-based management for administrators in the Region XII Service Center area in Texas.
Contributing Partner: UNT Libraries
Susceptibility of College Students to Alcohol Abuse and Alcohol Related Problems: the Impact of Family Environmental Factors

Susceptibility of College Students to Alcohol Abuse and Alcohol Related Problems: the Impact of Family Environmental Factors

Date: December 1998
Creator: Blue, James M. (James Michael)
Description: The purpose of this study was to examine the impact of parental divorce, level of family conflict, and family history of alcoholism on the alcohol use patterns of college students. Gender differences were also explored. Multivariate Analysis of Variance revealed mixed results. Parental marital status was found to have no significant effect on college students' alcohol behavior. High family conflict had a significant impact on both level of current alcohol use and level of alcohol related problems. A positive family history of alcoholism was found to have effects on the level of alcohol related problems encountered by students. Gender played a significant role, with males reporting higher levels of alcohol-related problems. No significant interactions were found. Results, contributions and limitations of the study are discussed.
Contributing Partner: UNT Libraries
Creating a Mythistory: Texas Historians in the Nineteenth Century

Creating a Mythistory: Texas Historians in the Nineteenth Century

Date: August 1998
Creator: McLemore, Laura Lyons, 1950-
Description: Many historians have acknowledged the temptation to portray people as they see themselves and wish to be seen, blending history and ideology. The result is "mythistory." Twentieth century Texas writers and historians, remarking upon the exceptional durability of the Texas mythistory that emerged from the nineteenth century, have questioned its resistance to revision throughout the twentieth century. By placing the writing of Texas history within the context of American and European intellectual climates and history writing generally, from the close of the eighteenth century to the beginning of the twentieth, it is possible to identify a pattern that provides some insight into the popularity and persistence of Texas mythistory.
Contributing Partner: UNT Libraries
An Exploratory Investigation of the Origins and Regulatory Actions of the United Kingdom's Financial Reporting Review Panel

An Exploratory Investigation of the Origins and Regulatory Actions of the United Kingdom's Financial Reporting Review Panel

Date: December 1998
Creator: Styles, Alan K. (Alan Keith)
Description: In 1990, the accounting profession and the British government worked together to establish a new regulatory framework for financial reporting in the United Kingdom (UK), the Financial Reporting Council (FRC) and its two subsidiaries, the Accounting Standards Board (ASB) and the Financial Reporting Review Panel (FRRP). The FRRP enforces companies' compliance with the ASB's accounting standards and the accounting provisions of the UK Companies Act. Only one study, Brandt et al. (1997), has examined the activities and effectiveness of the FRRP. This dissertation attempts to extend Brandt et. al (1997) and add to understanding of the origins and regulatory actions of the FRRP.
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Natural Smooth Measures on the Leaves of the Unstable Manifold of Open Billiard Dynamical Systems

Natural Smooth Measures on the Leaves of the Unstable Manifold of Open Billiard Dynamical Systems

Date: December 1998
Creator: Richardson, Peter A. (Peter Adolph), 1955-
Description: In this paper, we prove, for a certain class of open billiard dynamical systems, the existence of a family of smooth probability measures on the leaves of the dynamical system's unstable manifold. These measures describe the conditional asymptotic behavior of forward trajectories of the system. Furthermore, properties of these families are proven which are germane to the PYC programme for these systems. Strong sufficient conditions for the uniqueness of such families are given which depend upon geometric properties of the system's phase space. In particular, these results hold for a fairly nonrestrictive class of triangular configurations of scatterers.
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The Rhetoric of Posthumanism in Four Twentieth-Century International Novels

The Rhetoric of Posthumanism in Four Twentieth-Century International Novels

Date: August 1998
Creator: Lin, Lidan
Description: The dissertation traces the trope of the incomplete character in four twentieth-century cosmopolitan novels that reflect European colonialism in a global context. I argue that, by creating characters sharply aware of the insufficiency of the Self and thus constantly seeking the constitutive participation of the Other, the four authors E. M. Forster, Samuel Beckett, J. M. Coetzee, and Congwen Shen all dramatize the incomplete character as an agent of postcolonial resistance to Western humanism that, tending to enforce the divide between the Self and the Other, provided the epistemological basis for the emergence of European colonialism. For example, Fielding's good-willed aspiration to forge cross-cultural friendship in A Passage to India; Murphy's dogged search for recognition of his Irish identity in Murphy; Susan's unfailing compassion to restore Friday's lost speech in Foe; and Changshun Teng, the Chinese orange-grower's warm-hearted generosity toward his customers in Long River--all these textual occasions dramatize the incomplete character's anxiety over the Other's rejection that will impair the fullness of his or her being, rendering it solitary and empty. I relate this anxiety to the theory of "posthumanism" advanced by such thinkers as Marx, Bakhtin, Sartre, and Lacan; in their texts the humanist view of the individual ...
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Convergence of Self and Other Ratings of Personality: a Structural Equation Analysis

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

Date: May 1998
Creator: McElhenie, Michael K. (Michael Keith)
Description: 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.
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Analysis of Phytoplankton Responses to Water Chemistry Dynamics in a Moderately Eutrophic North Texas Reservoir

Analysis of Phytoplankton Responses to Water Chemistry Dynamics in a Moderately Eutrophic North Texas Reservoir

Date: May 1998
Creator: Banks, Kenneth E. (Kenneth Edward)
Description: Canonical correspondence analysis (CCA) was used to explore relationships between measured environmental variables and in situ phytoplankton communities in a moderately eutrophic North Texas Reservoir.
Contributing Partner: UNT Libraries
Women in Higher Education Administration: An Analysis for 1983-1998

Women in Higher Education Administration: An Analysis for 1983-1998

Date: August 1998
Creator: Muskopf, Sandra Jane
Description: The objective of this study was to identify if women have made statistically significant increases as top-level administrators in institutions of higher education during the period 1983-98. The research focused on the following areas: (1) Have women made significant increases as administrators during 1983-98? (2) Have women made significant increases in their proportion of total administrators during 1983-98 in the following areas: (a) comprehensive institutions, (b) doctoral institutions, (c) liberal arts institutions, and (d) research institutions? (3) Has the proportion of women administrators in private institutions increased significantly more than the proportion of women administrators in public institutions for 1983-98?
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Kinetics and Mechanisms of Metal Carbonyls

Kinetics and Mechanisms of Metal Carbonyls

Date: May 1998
Creator: Ladogana, Santino
Description: Pulsed laser flash photolysis with both visible and infrared detection has been applied to the study of the displacement of weakly coordinating ligands (Lw) by strongly "trapping" nucleophiles (Ls) containing either an olefinic functionality (Ls = 1-hexene, 1-decene, 1-tetradecene) or nitrogen (Ls = acetonitrile, hydrocinnamonitrile) from the photogenerated 16 electron pentacarbonylchromium (0) intermediate. 5-Chloropent-l-ene (Cl-ol), a potentially bidentate ligand, has been shown to form (ol-Cl) pentacarbonylchromium (0), in which Cl-ol is bonded to Cr via a lone pair on the chlorine, and isomerize to (Cl-ol) pentacarbonylchromium (0), in which Cl-ol is bonded to the olefinic functionality on the submillisecond time scale. This process has been studied in both the infrared and visible region employing both fluorobenzene or n-heptane as the "inert" diluent. Parallel studies employing 1-chlorobutane and 1-hexene were also evaluated and showed great similiarity with the Cl-ol system. The data supported a largely dissociative process with a possibility of a small interchange process involving the H's on the alkyl chain. Studies were also carried out for various Cr(CO)6/arene/Ls systems (arene = various alkyl or halogenated substituted benzenes). The data indicated that for both C6H5R (R=various alkyl chains) or multi-alkyl substituted arenes (i.e. o-xylene, 1,2,3-trimethylbenzene) containing an "unhindered" ring-edge, bonding ...
Contributing Partner: UNT Libraries
An Analysis of the Performance of a Clinical Sample of African American, Caucasian, and Hispanic Children on the WISC-III

An Analysis of the Performance of a Clinical Sample of African American, Caucasian, and Hispanic Children on the WISC-III

Date: December 1998
Creator: Ewing, Melissa L. (Melissa Lynn)
Description: The goals of revision for the Wechsler Intelligence Scale for Children-Third Edition included enhancement of the factor structure, improvement of subtests, and revision of norms. The researchers reported that the very few items that were found to be biased were replaced. The WISC-III performance of a clinical sample of African American, Caucasian, and Hispanic children was analyzed to determine if the test bias was eliminated as claimed in the goals of the revision.
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Pyrimidine Biosynthesis in the Genus Streptomyces : Characterization of Aspartate Transcarbamoylase and Its Interaction with Other Pyrimidine Enzymes

Pyrimidine Biosynthesis in the Genus Streptomyces : Characterization of Aspartate Transcarbamoylase and Its Interaction with Other Pyrimidine Enzymes

Date: May 1998
Creator: Hughes, Lee E. (Lee Everette)
Description: Aspartate transcarbamoylase (ATCase) of Streptomyces was characterized and its interaction with other pyrimidine enzymes explored.
Contributing Partner: UNT Libraries
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