UNT Theses and Dissertations - 18,412 Matching Results

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Microstructure Evolution in Laser Deposited Nickel-Titanium-Carbon in situ Metal Matrix Composite

Description: Ni/TiC metal matrix composites have been processed using the laser engineered net shaping (LENS) process. As nickel does not form an equilibrium carbide phase, addition of a strong carbide former in the form of titanium reinforces the nickel matrix resulting in a promising hybrid material for both surface engineering as well as high temperature structural applications. Changing the relative amounts of titanium and carbon in the nickel matrix, relatively low volume fraction of refined homogeneously distributed carbide precipitates, formation of in-situ carbide precipitates and the microstructural changes are investigated. The composites have been characterized in detail using x-ray diffraction, scanning electron microscopy (including energy dispersive spectroscopy (XEDS) mapping and electron backscatter diffraction (EBSD)), Auger electron spectroscopy, and transmission (including high resolution) electron microscopy. Both primary and eutectic titanium carbides, observed in this composite, exhibited the fcc-TiC structure (NaCl-type). Details of the orientation relationship between Ni and TiC have been studied using SEM-EBSD and high resolution TEM. The results of micro-hardness and tribology tests indicate that these composites have a relatively high hardness and a steady-state friction coefficient of ~0.5, both of which are improvements in comparison to LENS deposited pure Ni.
Date: December 2010
Creator: Gopagoni, Sundeep
Partner: UNT Libraries

Probabilistic Analysis of Contracting Ebola Virus Using Contextual Intelligence

Description: The outbreak of the Ebola virus was declared a Public Health Emergency of International Concern by the World Health Organisation (WHO). Due to the complex nature of the outbreak, the Centers for Disease Control and Prevention (CDC) had created interim guidance for monitoring people potentially exposed to Ebola and for evaluating their intended travel and restricting the movements of carriers when needed. Tools to evaluate the risk of individuals and groups of individuals contracting the disease could mitigate the growing anxiety and fear. The goal is to understand and analyze the nature of risk an individual would face when he/she comes in contact with a carrier. This thesis presents a tool that makes use of contextual data intelligence to predict the risk factor of individuals who come in contact with the carrier.
Date: May 2017
Creator: Gopala Krishnan, Arjun
Partner: UNT Libraries

An Empirical Study on the Use of Promotion in Hospitals

Description: The role of marketing and marketing communication in hospitals has grown in the last decade. The need for hospitals to make careful decisions about their marketing communication efforts is mandated, given the changes taking place in the hospital industry. The purpose of this dissertation was to conduct empirical research to determine whether for-profit and non-profit hospitals perceive and utilize promotion as a marketing strategy element. The two steps taken included: identifying important factors considered by hospital administrators and marketing staff in the development of communication messages designed for patients, hospital staff and medical staff; and testing the factors developed and studying the attitudes of hospital personnel toward promotion using a national sample of hospitals. In phase 1, focus group interviews were conducted in a surrogate for-profit hospital and a surrogate non-profit hospital. In phase 2, an original mail questionnaire was used to collect data from a sample of 80 hospitals. A total of 38 hospitals participated, providing 114 usable responses. Test statistics included content analysis, Chi-Square, Pearson correlation coefficient and Analysis of Variance. The results of the focus group study indicated the practice of marketing in hospitals is in its early growth stages and marketing is viewed as nothing more than advertising and public relations. The results of the mail survey indicated that respondents in small for-profit hospitals with 20 to 30 years of experience as professionals, with key decision making authority, are favorably disposed to marketing and marketing communication. It was also found that respondents in large non-profit hospitals are very positive towards marketing. In contrast, respondents in medium and large for-profit hospitals, who are not directly involved in decision making, tend to be less positive towards marketing. The study serves as a basis for future research which may involve, (1) a larger sample frame, (2) hospitals in inner-city ...
Date: December 1988
Creator: Gopalakrishna, Pradeep
Partner: UNT Libraries

Market Reactions to Accounting Policy Deliberations the Case of Pensions (SFAS No. 87)

Description: This study had two basic objectives. The first was to determine the stock market reactions to the pension policy deliberations. The second was to further our understanding of the significance of the FASB's due process. The author selected 13 critical events that preceded passage of SFAS No. 87 and designed a quasi experiment to examine the stock market reaction around the above events. Two portfolios were constructed to test the hypotheses. The first portfolio consisted of firms in the experimental group (firms sponsoring a defined benefit pension plan) and the second portfolio consisted of firms in the control group (firms sponsoring a defined contribution pension plan). The two portfolios were matched on the basis of SIC code, debt to equity ratio and assets.
Date: December 1986
Creator: Gopalakrishnan, Venkataraman
Partner: UNT Libraries

Analysis of Thermoplastic Polyimide + Polymer Liquid Crystal Blends

Description: 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 of properties. The amorphous TPI + PLC blends also show the negative deviation of ACP from linearity with composition. The addition of PLC causes a decrease in the thermal conductivity in the transverse direction to the PLC orientation. The thermomechanical analysis indicates isotropic expansivity for the amorphous TPI and a small anisotropy for the semicrystalline TPI. The PLC shows large anisotropy in expansivity. Even 5 wt. % concentration of PLC in the blend induces considerable anisotropy in the expansivity. Thus, blends show controllable expansivity through PLC concentration. Amorphous TPI + PLC blends also show excellent film formability. The amorphous TPI ...
Date: May 1998
Creator: Gopalanarayanan, Bhaskar
Partner: UNT Libraries

A Study of the Functional Competencies of Southern Baptist Missionaries Who Originate Indigenous Churches in the Philippines

Description: This study was designed to identify the functional competencies necessary for a missionary to plant churches in the Philippines, to identify how those competencies can be recognized in individual missionaries, and to determine the percentage of personnel who possess specific functional competencies.
Date: December 1993
Creator: Gopffarth, William
Partner: UNT Libraries

The Impact on Achievement from Student and Parent Attitudes towards Using Smartphones in School

Description: The purpose of this research was to determine what type of correlations existed between student and parent attitudes towards using smartphones in school and the resulting impact on achievement, specifically for low-achieving students. Participants in the study were third-grade students and their parents from a primary school in Singapore. The study employed a quantitative analysis to understand the correlations among the different participant groups. The instruments used were Likert-based surveys, along with scores from mid-year and end-of-year achievement exams in English and science. The three most relevant major findings showed that (a) low-achieving students show a positive attitude toward completing science activities, which correlates with an increase in science achievement; (b) the parents of low-achieving students appear to provide their children with autonomy in using their smartphones, which correlates with an increase in science achievement; and (c) having a smartphone and using the smartphone to complete school work is important to low-achieving students and their parents.
Date: December 2016
Creator: Gordesky, Joshua
Partner: UNT Libraries

Corporate Sale-and-Leaseback Transactions: An Examination of Corporate Incentives, Wealth Effects and Dealer Spreads

Description: There is a limited amount of research dealing with the wealth effects of sale-and-leaseback transactions, but previous research has focused predominantly on the tax effects of these transactions. The results of these studies have often been in conflict with one another. This dissertation shows that tax effects do play a role in determining the wealth effect of sale-and-leasebacks on stockholders, but there exists a framework of finance research that suggests several other factors could play a determining role as well.
Date: August 1993
Creator: Gordon, Bruce L. (Bruce Lee)
Partner: UNT Libraries

The effects of diphenylhydantoin on the lymphoreticular tissues of the rat

Description: A study was made of the effects of diphenylhydantoin (DPH) and the carrier solution on the spleen, lymph node, and thymus. DPH was injected i.p. at concentrations of 5 and 10 mg./100gm. for 30 and 60 days. Hematologic effects observed were leucocytosis, neutrophilia, eosinophilia, and lymphopenia. Respiratory measurements of lymph node tissue slices were made using the oxygen electrode method.
Date: August 1976
Creator: Gordon, Charles K.
Partner: UNT Libraries

Organizational Rhetoric in the Academy: Junior Faculty Perceptions and Roles

Description: The purpose of this project was to examine the perceptions of junior faculty members as they relate to roles and expectations related to the tenure process. The study utilized a mixed methods approach to gain a multifaceted perspective of this complex process. I employed a quantitative and qualitative survey to explore junior faculty perceptions regarding roles related to promotion and tenure policies. In addition, I conducted fantasy theme analysis (FTA) to explore the organizational rhetoric related to these policies. Findings from the study illustrate the continued presence of the "publish or perish" paradigm, as well as issues related to role conflict within the context of organizational rhetoric.
Date: December 2008
Creator: Gordon, Cynthia K.
Partner: UNT Libraries

Trade negotiations in agriculture: a comparative study of the US & the EC

Description: This study applies Destler's institutional counterweights to Putnam's two-level analysis, substituting Liberal Institutionalism and Realism for internationalism and isolationism, in a comparative case study of the roles played by the United States and the European Economic Community in multilateral trade negotiations in agriculture under the aegis of the General Agreement for Tariffs and Trade during the first half of the Uruguay round.
Date: December 1994
Creator: Gordon, H. William (Harold William)
Partner: UNT Libraries

Employment of the Rorschach Inkblot Test with the Devries Suicide Inventory

Description: This investigation represents an attempt to employ the Devries Suicide Prediction Scale and the Rorschach Inkblot Test in a two-stage predictive model which was designed to decrease the high false positive rate associated with the Devries and to design a way in which the Rorschach could be used efficiently in suicide prediction in a large mental hospital setting. The Rorschach was not found to significantly improve the predictive ability of the Devries. An unexpectedly high percentage of mental patients in the study, thirty-eight percent, admitted to previous suicide attempts, raising the question of whether suicidal behavior is not more common than is usually thought.
Date: May 1976
Creator: Gordon, James L.
Partner: UNT Libraries

Empirical Tests of the Signaling and Monitoring Hypotheses for Initial Public Offerings

Description: The research questions investigated are: 1. Are the expected post-issue fractional holdings of the directors and officers, venture capitalists and institutions signals of firm value? 2. Are the expected post-issue fractional holdings of the directors and officers, venture capitalists and institutions signals of underpricing? and 3. Are the directors and officers, venture capitalists and institutions monitors of IPO investments? The signaling theory developed by Grinblatt and Hwang (1989) (GH) and the monitoring theory for IPO investments have been used to develop the hypotheses for this dissertation. Four factors make my methodology unique. These factors are: 1. I apply and test the GH IPO signaling model over a unique data set collected from the IPO prospectuses, proxy statements and annual reports; 2. I disaggregate the expected post-issue holdings of the different groups of pre-issue blockholders and insiders and hypothesizes that these individual groups represents signals of firm value and underpricing; 3. I hypothesize that these groups, in aggregate and separately, monitor IPO investments over the long term; And 4. I develop signaling and monitoring hypotheses to make predictions at the two stages of the IPO. The results show that firm value is positively related to the level of underpricing, at a given variance of the firms cash flows; the level of underpricing is positively related to the holdings of the directors and officers as a group and the aggregate of the directors and officers, VCs and institutions, at given variances of the firm's cash flows; the firm value is not related to the level of underpricing, at a given level of capital outlay and holdings of either the aggregate blockholders, directors and officers, VCs or institutions. For the monitoring hypotheses, the results show that the long-run buy-and-hold-returns are positively related to the investment bank reputation and the gross spread. Also, the ...
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Date: May 2006
Creator: Gordon, Sean Anthony Garnet
Partner: UNT Libraries

Strategic Reorientation in the Computer Software and Furniture Industries: a Hierarchical Regression Analysis

Description: Insufficient literature exists in the area of incremental and revolutionary change to explain and predict the convergence and reorientation phenomena happening in organizations. The process of strategic reorientation involves the internal organizational complexities of fast-paced (within two years) changes in competitive strategy as a necessary condition coupled with changes in at least two of organization structure, power distribution, and control systems. Antecedent forces believed to influence the discontinuous change process include industry sales turbulence, structural inertia/firm size, firm past financial performance, CEO turnover, top management team turnover, management team heterogeneity, management environmental awareness, and external attributions for negative financial performance. Punctuated equilibrium was the foundational theory for this study in which a strategic reorientation model published in Strategic Management Journal was reconstructed. The research question was: What seem to be the significant time-based antecedent forces or conditions that lead to strategic reorientation? The study used two hierarchical logit regression models to analyze data gathered from COMPUSTAT PC Industrial Data Base and Compact Disclosure (CD-ROM) over the years 1987-1993 from the turbulent computer software and stable furniture industries. Qualitative data were found in 10-K reports and President's Letters in Annual Reports filed with the SEC and available on Laserdisclosure. The sample, exclusive of 3 multivariate outliers, included 74 software firms and 43 furniture firms for a pooled total of 117 firms. When separate industries were analyzed using the first of the Systat logit hierarchical regressions, results showed no statistically significant effects. By contrast, when data were pooled, the second hierarchical logit regression model, which included industry turbulence and firm size, showed these one-tailed statistically significant results: strategic reorientation is positively affected by prior industry turbulence and CEO turnover, but is negatively affected by prior top management team turnover and the interaction between industry turbulence and external attributions for negative financial performance.
Date: August 1995
Creator: Gordon, Shelley S. (Shelley Sampson)
Partner: UNT Libraries

Sex Dimension of the Dogmatism Scale: A Factor Analysis

Description: The problem of this study was to factor-analyze Rokeach's Dogmatism Scale and examine the factor structures of the scale for differences in the solutions obtained for the male and female groups. It was hypothesized that the Dogmatism Scale consists of several discriminable dimensions of the construct dogmatism and that these dimensions differ significantly for males and females. The dogmatism scale was administered to 186 male and 115 female college students. The male and female solutions yielded thirteen and sixteen orthogonal factors, respectively. Six male factors and eleven female factors were unique to their respective sex groups, indicating that the Dogmatism Scale is multidimensional and that significant sex differences are found when these dimensions are examined.
Date: May 1974
Creator: Gordon, William Knox
Partner: UNT Libraries

Influence of parental swimming stamina on the cardiac and metabolic performance of larval zebrafish (Danio rerio).

Description: Superior swimming stamina in adult fish is presumably passed on to their offspring, but the ontogeny of the appearance of superior stamina and the requisite enhanced cardio-respiratory support for locomotion in larval fishes has not been determined. Is the expression of the suite of parental traits enabling superior swimming stamina in their offspring dependent upon their achieving juvenile/adult morphology, or does it appear earlier in their larvae? To answer this, adults were classified into three groups based on swimming stamina, followed by measurement of length, mass, and width. Larval offspring from the two parental groups -high stamina larvae (HSL) and low stamina larvae (LSL)- were reared at 27°C in aerated water (21% O2). Routine and active heart rate, routine and active mass specific oxygen consumption were recorded through 21dpf, and cost of transport (COT) and factorial aerobic scope were derived from oxygen consumption measurements. Routine heart rate at 2dpf of LSL was 164 ± 1 b·min-1, compared to only 125 ± 2 b·min-1 for HSL. Routine heart rate subsequently peaked at 203 ± 1 b·min-1 at 5dpf in the HSL group, compared to 207 ± 1 b·min-1, at 4dpf in the LSP larvae. Active heart rate at 5 dpf of LSL was 218 ± 2 b·min-1 compared to 216 ± 2 b·min-1 for HSL. Active heart rate increased slightly to 227 ± 2 b·min-1 for LSL before decreasing again, while active heart rate remained relatively constant for HSL. Routine O2 consumption at 2dpf of HSL was 0.09 μmol·mg-1·hr-1, compared to 0.03 μmol·mg-1·hr-1 in LSL. Routine O2 consumption subsequently peaked at 0.70 μmol·mg-1·hr-1 at 9dpf in the HSL, compared to 0.71 μmol·mg-1·hr-1, at 9dpf in the LSL. These values dramatically decreased before leveling off at around 0.20 μmol·mg-1·hr-1 and 0.15 μmol·mg-1·h-1, respectively. Active O2 consumption at 5dpf for HSL was 0.38 ...
Date: May 2007
Creator: Gore, Matthew R.
Partner: UNT Libraries

Hobbes’s Deceiving God: the Correspondence Between Thomas Hobbes and Rene Descartes

Description: In presenting their correspondence, I highlight the means in which Hobbes is able to divorce nature and politics in his philosophy. This is done by bringing to light Hobbes’s agreement with Descartes’s deceiving God argument. First, I demonstrate Hobbes’s hidden agreement with it by analyzing his objection to Descartes’s first Meditation. Second, I show that Hobbes and Descartes both retreat into consciousness in order to deal with the possibility of deception on the behalf of God. Third, I trace Hobbes’s rational justification for entertaining that very possibility. Fourth, I bring forward Hobbes’s certain principle, that God is incomprehensible. Fifth, I demonstrate Hobbes’s rationalization for rendering nature incomprehensible in turn. From this key insight, the differences between the two philosophers stand out more. Whereas Descartes rids himself of the possibility of a deceiving God, Hobbes does not. Sixth, I show that Descartes needs to rid himself of that possibility in order to have a basis for science, Hobbes’s science is such that he does not need to rid himself of that possibility. My investigation ends by considering both Hobbes’s and Descartes’s stance on nature, in relation to politics. I find that Hobbes’s principle is much more practical that Descartes’s principle. Hobbes’s principle is shown to be much more instructive and sustainable for human life. In conclusion, this analysis of the origins, principles, and orientation of the two philosopher’s thought brings forward the overarching question, whether the recovery of value and meaning is to be brought about in nature, or in civilization.
Date: August 2015
Creator: Gorescu, Gabriela
Partner: UNT Libraries

Laser Ablation Inductively Coupled Plasma Mass Spectrometry and Raman Spectroscopy Imaging of Biological Tissues

Description: Laser Ablation Inductively coupled plasma mass spectrometry (LA-ICP-MS) and Raman spectroscopy are both powerful imaging techniques. Their applications are numerous and extremely potential in the field of biology. In order to improve upon LA-ICP-MS an in-house built cold cell was developed and its effectiveness studied by imaging Brassica napus seeds. To further apply LA-ICP-MS and Raman imaging to the field of entomology a prong gilled mayfly (Ephemeroptera: Leptophlebiidae) from the Róbalo River, located on Navarino Island in Chile, was studied. Analysis of both samples showcased LA-ICP-MS and Raman spectroscopy as effective instruments for imaging trace elements and larger molecules in biological samples respectively.
Date: May 2016
Creator: Gorishek, Emma
Partner: UNT Libraries