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 Collection: UNT Theses and Dissertations
Kiln-Fired Glass in the Junior College Arts and Crafts Program

Kiln-Fired Glass in the Junior College Arts and Crafts Program

Date: August 1963
Creator: Buchanan, Robert Gordon
Description: The problem with which this investigation is concerned is the discovery of suitable uses for the enameling kiln in the arts and crafts program at the junior college level in the production of kiln-formed glass and the testing of methods and materials that will permit work of aesthetic merit at a nominal cost to the students and the school.
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Kindergarten Teacher Competencies Ranked by Kindergarten Teachers and Kindergarten Teacher Trainers

Kindergarten Teacher Competencies Ranked by Kindergarten Teachers and Kindergarten Teacher Trainers

Date: August 1973
Creator: Hicks, Vivian Agnes
Description: This study is concerned with the problem of determining the competencies which inservice kindergarten teachers and kindergarten-teacher trainers consider most important for teaching kindergarten. There are four purposes of the study: to identify specific competencies needed to teach kindergarten, to determine the teacher competencies considered most important by kindergarten teachers, to determine teacher competencies considered most important by teacher trainers, and to compare the rankings of teacher competencies by kindergarten teachers and kindergarten-teacher trainers.
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Kinetic and Chemical Mechanism of 6-phosphogluconate Dehydrogenase from Candida Utilis

Kinetic and Chemical Mechanism of 6-phosphogluconate Dehydrogenase from Candida Utilis

Date: May 1993
Creator: Berdis, Anthony J. (Anthony Joseph)
Description: A complete initial velocity study of the 6-phosphogluconate dehydrogenase from Candida utilis in both reaction directions suggests a rapid equilibrium random kinetic mechanism with dead-end E:NADP:(ribulose 5-phosphate) and E:NADPH:(6- phosphogluconate) complexes. Initial velocity studies obtained as a function of pH and using NAD as the dinucleotide substrate for the reaction suggest that the 2'-phosphate is critical for productive binding of the dinucleotide substrate. Primary deuterium isotope effects using 3-<i-6-phosphogluconate were obtained for the 6-phosphogluconate dehydrogenase reaction using NADP and various alternative inucleotide substrates.
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Kinetic and Chemical Mechanism of O-Acetylserine Sulfhydrylase-B from Salmonella Typhimurium

Kinetic and Chemical Mechanism of O-Acetylserine Sulfhydrylase-B from Salmonella Typhimurium

Date: August 1993
Creator: Tai, Chia-Hui
Description: Initial velocity studies of O-acetylserine sulfhydrylase-B (OASS-B) from Salmonella typhimurium using both natural and alternative substrates suggest a Bi Bi ping pong kinetic mechanism with double substrate competitive inhibition. The ping pong mechanism is corroborated by a qualitative and quantitative analysis of product and dead-end inhibition. Product inhibition by acetate is S-parabolic noncompetitive, indication of a combination of acetate with E followed by OAS. These data suggest some randomness to the OASS-B kinetic mechanism. The pH dependence of kinetic parameters was determined in order to obtain information on the acid-base chemical mechanism for the OASS-B reaction. A mechanism is proposed in which an enzyme general base accepts a proton from α-amine of O-acetylserine, while a second enzyme general base acts by polarizing the acetyl carbonyl assisting in the β-elimination of the acetyl group of O-acetylserine. The ε-amine of the active site lysine acts as a general base to abstract the α-proton in the β-elimination of acetate. At the end of the first half reaction the ε-amine of the active site lysine that formed the internal Schiff base and the general base are protonated. The resulting α-aminoacrylate intermediate undergoes a Michael addition with HS‾ and the active site lysine donates its ...
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Kinetic Investigation of the Gas Phase Atomic Sulfur and Nitrogen Dioxide Reaction

Kinetic Investigation of the Gas Phase Atomic Sulfur and Nitrogen Dioxide Reaction

Date: May 2011
Creator: Thompson, Kristopher Michael
Description: The kinetics of the reaction of atomic sulfur and nitrogen dioxide have been investigated over the temperature range 298 to 650 K and pressures from 14 - 405 mbar using the laser flash photolysis - resonance fluorescence technique. The overall bimolecular rate expression k (T) = (1.88 ± 0.49) x10-11 exp-(4.14 ± 0.10 kJ mol-1)/RT cm3 molecule-1 s-1 is derived. Ab initio calculations were performed at the CCSD(T)/CBS level of theory and a potential energy surface has been derived. RRKM theory calculations were performed on the system. It is found that an initially formed SNO2 is vibrationally excited and the rate of collisional stabilization is slower than the rate of dissociation to SO + NO products by a factor of 100 - 1000, under the experimental conditions.
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The Kinetic Structures of Metric Temporal Patterns in Selected Beginning Piano Method Series

The Kinetic Structures of Metric Temporal Patterns in Selected Beginning Piano Method Series

Date: August 1994
Creator: Chan, Alton
Description: The purpose of this study was to investigate the kinetic structures or reinforcement schedules of metric temporal patterns (metric combination of note values within a measure) in five best-selling beginning piano method series. Based upon a survey mailed to 98 music dealers, the five best-selling beginning piano method series in 1992 and 1993 were identified as: the Alfred Basic Piano Library, Bastien Piano Basics, David Carr Glover Piano Library, John. W. Schaum Piano Course, and John Thompson Modern Course for Piano. A coding system was developed for identifying the numerical appearances and occurrences of various metric temporal patterns per learning piece within each method series. Several computer programs were written to compute the kinetic structures, scope, and pacing of metric temporal patterns for each method series. The derived data were then compared to delineate relationships between the three analytical variables.
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Kinetic studies and computational modeling of atomic chlorine reactions in the gas phase.

Kinetic studies and computational modeling of atomic chlorine reactions in the gas phase.

Date: August 2009
Creator: Alecu, Ionut M.
Description: The gas phase reactions of atomic chlorine with hydrogen sulfide, ammonia, benzene, and ethylene are investigated using the laser flash photolysis / resonance fluorescence experimental technique. In addition, the kinetics of the reverse processes for the latter two elementary reactions are also studied experimentally. The absolute rate constants for these processes are measured over a wide range of conditions, and the results offer new accurate information about the reactivity and thermochemistry of these systems. The temperature dependences of these reactions are interpreted via the Arrhenius equation, which yields significantly negative activation energies for the reaction of the chlorine atom and hydrogen sulfide as well as for that between the phenyl radical and hydrogen chloride. Positive activation energies which are smaller than the overall endothermicity are measured for the reactions between atomic chlorine with ammonia and ethylene, which suggests that the reverse processes for these reactions also possess negative activation energies. The enthalpies of formation of the phenyl and &#946;-chlorovinyl are assessed via the third-law method. The stability and reactivity of each reaction system is further rationalized based on potential energy surfaces, computed with high-level ab initio quantum mechanical methods and refined through the inclusion of effects which arise from the ...
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Kinetic Studies and Vibrational Spectra of Disubstituted Metal Carbonyls

Kinetic Studies and Vibrational Spectra of Disubstituted Metal Carbonyls

Date: May 1972
Creator: Jernigan, Robert Thorne
Description: The oxidative elimination reactions of (5-X-phen)Mo(C0)₄ (X = H, CH₃, Cl, NO₂; phen = o-phenanthroline) and (3,4,7,8-(CH₃)₄-phen)Mo(CO)₄ with mercuric chloride in acetone have been investigated. In these reactions, a carbon monoxide group is replaced by two univalent ligands, accompanied by the corresponding increase in coordination number and formal oxidation state of the central metal atom, to give products of the type, (X-phen)Mo(CO)₃(Cl)HgCl. With the exception of (3,4,7,8-(CH₃)₄-phen), the substituted o-phenanthrolines were selected so as to minimize steric differences from one substrate to another while obtaining the widest range of pKₐ of the ligand.
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Kinetic Studies of Hydroxyl and Hydrogen Atom Reactions

Kinetic Studies of Hydroxyl and Hydrogen Atom Reactions

Date: May 2002
Creator: Hu, Xiaohua
Description: Gas phase kinetics of the reactions involving hydroxyl radical and hydrogen atom were studied using experimental and ab initio theoretical techniques. The rate constant for the H + H2S reaction has been measured from 298 to 598 K by the laser photolysis/resonance fluorescence (LP-RF) technique. The transition state theory (TST) analysis coupled with the measurements support the suggestion that the reaction shows significant curvature in the Arrhenius plot. The LP-RF technique was also used to measure the rate constant of the H + CH3Br reaction over the temperature range 400-813 K. TST and density functional theory (DFT) calculations show that the dominant reaction channel is Br-abstraction. The reaction H + CF2=CF-CF=CF2 was first studied by flash photolysis/resonance fluorescence (FP-RF) method. The experiments of this work revealed distinctly non-Arrhenius behavior, which was interpreted in terms of a change in mechanism. DFT calculations suggest that the adduct is CF2H-CF•-CF=CF2. At lower temperatures a mixture of this molecule and CF2•-CFH-CF=CF2 is likely. The theoretical calculations show that H atom migrates in the fluoroethyl radicals through a bridging intermediate, and the barrier height for this process is lower in the less fluorinated ethyl radical. High level computations were also employed in studies of the ...
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Kinetics and Mechanism Study of Diphenylketene Cycloadditions

Kinetics and Mechanism Study of Diphenylketene Cycloadditions

Date: August 1967
Creator: O'Neal, Hubert Ronald
Description: From a review of the published work in the field of cycloadditions, it is evident that further research is needed to establish the mechanism of ketene cycloadditions. This work was initiated with the intent of obtaining kinetic data which will contribute to the elucidation of the mechanism of ketene cycloadditions.
Contributing Partner: UNT Libraries