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Investigation of Lead Hydrolytic Polymerization and Interactions with Organic Ligands in the Soil/Sediment-Water Environment

Investigation of Lead Hydrolytic Polymerization and Interactions with Organic Ligands in the Soil/Sediment-Water Environment

Date: December 2002
Creator: Sanmanee, Natdhera
Description: The objective of this research was to investigate lead speciation in the soil/sediment-water environment and to better understand how the species affect lead mobility under different environmental conditions. The research involved both field soil and sediment samples as well as standard lead solutions. Field samples were fully characterized and extracted by aqueous and organic solvents. The results were compared and evaluated with the metal speciation model, MINTEQA2. Hydrolytic polymerization and organic complexation studies were conducted with standard lead solutions under controlled experimental conditions. Results of the field samples showed that pH, dissolved cations, ionic strength, dissolved organic matter, and nature of the soil/sediment matrix play major roles in the distribution and mobility of lead (Pb) from contaminated sites. In the aqueous equilibration experiment, the magnitude of Pb2+ solubilization was in the order of pH4>pH7>pH9. The results were in good agreement with MINTEQA2 predictions. An important finding of the research is the detection of Pb polymerization species under controlled experimental conditions. At pH 5.22, Pb polymeric species were formed at rate of 0.03 per day. The role of Pb complexation with organic matter was evaluated in both field and standard samples. Different methodologies showed three types of organically bound Pb. A ...
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Investigations of Thermochemistry and the Kinetics of H Atom Radical Reactions

Investigations of Thermochemistry and the Kinetics of H Atom Radical Reactions

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Date: December 2002
Creator: Peebles, Lynda Renee
Description: The thermochemistry of several species, and the kinetics of various H atom radical reactions relevant to atmospheric and combustion chemistry were investigated using ab initio theoretical techniques and the flash photolysis / resonance fluorescence technique. Using ab initio quantum mechanical calculations up to the G3 level of theory, the C-H bond strengths of several alkanes were calculated. The bond strengths were calculated using two working reactions. From the results, it is apparent that the bond strengths decrease as methyl groups are added to the central carbon. The results are in good agreement with recent experimental halogenation kinetic studies. Hydrogen bond strengths with sulfur and oxygen were studied via CCSD(T) theory, together with extrapolation to the complete basis set limit. The results for the bond dissociation energies (ground state at 0 K, units: kJ mol-1) are: S-H = 349.9, S-D = 354.7, HS-H = 376.2, DS-D = 383.4, and HO-H = 492.6. These data compare well with experimental literature. The rate constants for the isotopic reactions of H + H2S, D + H2S, H + D2S, and D + D2S are studied at the QCISD(T)/6-311+G(3df,2p) level of theory. The contributions of the exchange reaction versus abstraction are examined through transition state ...
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Landscape forest modeling of the Luquillo Experimental Forest, Puerto Rico.

Landscape forest modeling of the Luquillo Experimental Forest, Puerto Rico.

Date: December 2002
Creator: Abbott-Wood, Chris
Description: This thesis contributes to modeling the dynamics of forest community response to environmental gradients and disturbances over a mountain landscape. A gap model (FACET) was parameterized for species of various forest types (Tabonuco, Colorado, Dwarf and Palm), for many terrain conditions and was modified and extended to include species response to excess soil moisture and hurricanes. Landscape cover types were defined by dominance of species of each forest type and canopy height. Parameters of the landscape model (MOSAIC) were calculated from multiple runs of FACET. These runs were determined by combining terrain variables (elevation and soil) and hurricane risk. MOSAIC runs were analyzed for distribution patterns. Geographic Information Systems software was used to process terrain variables, hurricane risk and MOSAIC model output.
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Layered Double Hydroxides: Morphology, Interlayer Anion, and the Origins of Life

Layered Double Hydroxides: Morphology, Interlayer Anion, and the Origins of Life

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Date: December 2002
Creator: Halcom-Yarberry, Faith Marie
Description: The preparation of layered double hydroxides via co-precipitation of a divalent/trivalent metal solution against a base results in 1 mm LDH particles with a disorganized metal lattice. Research was performed to address these morphological issues using techniques such as Ostwald ripening and precipitation via aluminate. Another interesting issue in layered double hydroxide materials is the uptake and orientation of anions into the interlayer. Questions about iron cyanide interlayer anions have been posed. Fourier transform infared spectroscopy and powder x-ray diffraction have been used to investigate these topics. It was found that factors such as orientation, anion charge, and anion structure depended on the divalent/trivalent metal ratio of the hydroxide layer and reactivity time. The cyanide self-addition reaction is an important reaction of classical prebiotic chemistry. This reaction has been shown to give rise to amino acids, purines and pyrimidines. At cyanide concentrations similar to that expected on the early earth, hydrolysis to formamide rather than self-addition occurs. One theory to alleviate this side reaction is the use of minerals or clays that are thought to concentrate and catalyze prebiotics of interest. Layered double hydroxides have been studied as a catalyst for this reaction.
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Levels of resourcefulness and motivation as they relate to sales force success: An examination of correlates using the hope theory.

Levels of resourcefulness and motivation as they relate to sales force success: An examination of correlates using the hope theory.

Date: December 2002
Creator: Pool, Patricia W.
Description: This study sought to determine whether a relationship existed between individual salesperson's levels of goal-directed cognition and motivation and their professional success as determined by the percentage of sales goals achieved. Salespersons represented two companies with national sales forces: one from the financial services industry and one from the apparel manufacturing industry. Both groups of salespeople were responsible for complex selling tasks. The skill sets for these professionals included high levels of communication skills, extensive product knowledge, and competitive market knowledge. Survey research, both paper and pencil and online, was conducted using the Hope Scale developed by C. R. Snyder and associates (1991). Hope is defined as a two-dimensional construct of goal-directed thinking: resourcefulness, thoughtful planning to overcome obstacles to goals, and motivation, cognition to sustain momentum toward goal achievement. Theoretically, upon assessing salespersons' Hope scores, organizations would be better prepared to assist those with low Hope Scale Scores (HSS) in one of the two areas. Those with low resourcefulness scores could be trained in cognitive techniques to overcome obstacles to goal achievement. Those with low motivational scores would be identified for further analysis, from a developmental perspective, to better determine what personally initiates and sustains motivation to attain their ...
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Metaphors, Myths, and Archetypes: Equal Paradigmatic Functions in Human Cognition?

Metaphors, Myths, and Archetypes: Equal Paradigmatic Functions in Human Cognition?

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Date: December 2002
Creator: Kalpakidis, Charalabos
Description: The overview of contributions to metaphor theory in Chapters 1 and 2, examined in reference to recent scholarship, suggests that the current theory of metaphor derives from long-standing traditions that regard metaphor as a crucial process of cognition. This overview calls to attention the necessity of a closer inspection of previous theories of metaphor. Chapter 3 takes initial steps in synthesizing views of domains of inquiry into cognitive processes of the human mind. It draws from cognitive models developed in linguistics and anthropology, taking into account hypotheses put forth by psychologists like Jung. It sets the stage for an analysis that intends to further understanding of how the East-West dichotomy guides, influences, and expresses cognitive processes. Although linguist George Lakoff denies the existence of a connection between metaphors, myths, and archetypes, Chapter 3 illustrates the possibility of a relationship among these phenomena. By synthesizing theoretical approaches, Chapter 3 initiates the development of a model suitable for the analysis of the East-West dichotomy as exercised in Chapter 4. As purely emergent from bodily experience, however, neither the concept of the East nor the concept of the West can be understood completely. There exist cultural experiences that may, depending on historical and ...
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A model for developing and disseminating multimedia materials for teacher educators.

A model for developing and disseminating multimedia materials for teacher educators.

Date: December 2002
Creator: Hodges, Linda S.
Description: The purpose of this study was to develop a model that would enhance the development, dissemination, and adoption of educational multimedia materials. The grounded theory definition of open coding was used to analyze data collected from the 3-year Technology Leadership Web Library Project at the University of North Texas. Weekly meeting minutes, email communication, reports, notes, questionnaires, and surveys were examined to determine major factors involved in the process of product development and dissemination. From the analysis of this study, five major factors in product development and dissemination were identified. These factors were leadership, team dynamics, expert advisors, feedback, and consumers. The synthesis of the factors led to the development of the PROMOTE (process revolving around ongoing management of team and evaluative feedback) model. The PROMOTE model is based on the establishment of a system that includes leadership, development team, and expert advisors at its center. The system is tied together with well-established feedback loops for stages of evaluation. The PROMOTE model is iterative and uses consumer feedback to generate new products. The PROMOTE model differs from other product development and evaluation models both in the focus of the process and the nature of the evaluation feedback.
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Music student teaching in Texas: A Delphi study of issues in the new millennium.

Music student teaching in Texas: A Delphi study of issues in the new millennium.

Date: December 2002
Creator: Cannon, Rodney M.
Description: The preparation of prospective music educators is a very complex undertaking that culminates with the student teaching practicum. However, the music student teaching experience may have less predictable expectations and results than the curriculum that precedes the event. The two-fold purpose of this study was (a) to investigate the music student teaching practicum in the State of Texas in an effort to establish current levels of success as perceived by the music educators involved in the process and (b) to identify any potentially problematic areas which might be in need of attention or revision. Thirty-six music educators (12 university supervisors, 12 cooperating teachers and 12 student teachers) who were recently involved in the music student teaching practicum in Texas were chosen as the sample in this two-round Delphi study. The first round Delphi survey, based on related literature, achieved consensus on 79% of the 108 item responses, and 15 of the 22 unresolved items reached consensus in round two of the Delphi process. The 34 sample members who completed the study ranked a final item in the second Delphi round concerning suggestions for the improvement of student teaching. The respondents showed a very high opinion of the music student teaching ...
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Nature By Design

Nature By Design

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Date: December 2002
Creator: Lingle, Linda A.
Description: Organic forms representing nature, but not particular species, are combined with elements signifying attitudes toward the natural world with an emphasis on North American culture. The viewer is encouraged to consider human effects on the environment. Aquarium Night Light and Trophy both refer to the human tendency for commercial exploitation coupled with the creation of nature images we sometimes seem to prefer over the reality of the natural world. Reliquary metaphorically connects traditional religious connotations associated with saints' relics to both a biblical injunction to use anything we needed from the natural world and our contemporary belief that exposure to nature can have beneficial effects on human mental, spiritual, and physical health.
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NMR Study of n-Propyllithium Aggregates

NMR Study of n-Propyllithium Aggregates

Date: December 2002
Creator: Davis, James W.
Description: A variable temperature 1H, 13C, and 6Li NMR study of n-propyl-6Li-lithium showed five different aggregates, similar to that in the literature as (RLi)n, n= 6, 8, 9, 9, 9. There were also a number of additional new species, identified as lithium hydride containing aggregates. Unexpectedly, a series of 13C{1H} 1-D NMR experiments with selective 6Li decoupling showed evidence for 13C-6Li spin-spin coupling between the previously reported (RLi)n aggregates and various hydride species.
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