Thesis (M.S.)--University of Missouri--Rolla, 2007. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed October 23, 2007) Includes bibliographical references (p. 54-57).

Thesis (D.E.)--Lamar University-Beaumont, 2003. / Includes bibliographical references.

No description available.

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

MSc, School of Chemistry, Faculty of Science, University of the Witwatersrand, 2011 / In this work, a detailed study of the evaluation of gold-based catalysts supported on manganese oxides for the oxidation of volatile organic compounds (VOCs) has been undertaken. Model catalysts were prepared by deposition-precipitation methods to establish the effect of the support on the catalytic activity of the gold catalysts. The catalysts were characterised by X-ray diffraction, transmission electron microscopy, N2–physisorption measurements and temperature programmed reduction techniques. The activity of the catalysts for VOC oxidation reactions were tested in a continuous flow fix bed glass reactor. The products were analysed by GC/TCD and GC/FID. The catalysts Au/TiO2, Au/Al2O3, Au/ZnO and Au/MnO2 were used for the VOC oxidation reaction. 2-propanol, 2-butanol and toluene were used as VOCs for the study. These were chosen because they are important indoor pollutants given their wide laboratory use and high volatility. Toluene was found to be the most difficult to oxidise, followed by 2-propanol. The effect of calcination temperature and preparation procedure was evaluated for the gold/manganese oxide catalysts. Au/b-MnO2 catalysts prepared by deposition-precipitation showed some catalytic performance which was less than the performance shown by Au/MnOx, prepared by co-precipitation. g-MnO2 proved to be more efficient in the oxidation of 2-propanol than pyrosulite phase MnO2. The addition of gold to any metal oxide support was found to enhance the oxidation of VOCs. Gold-based catalysts were more active than the Ce/MnO2 catalyst. Catalytic tests showed that Au/CeO2 was the superior catalyst for the total oxidation of toluene, 2-propanol and 2-butanol. Ceria is a highly reducible oxide and the formation of gold–ceria interactions produced an even more easily reduced material. University of the Witwatersrand, Johannesburg ii

This treatise studied two correlated important issues in atmospheric chemistry: real-time monitoring of ambient air and removal mechanisms of atmospheric hydrocarbons. An analytical system was designed for the purpose of identification and measurement of sub-ppb level hydrocarbons of different reactivities in air samples. This analytical system was then applied to a series of smog-chamber studies which simulated the removal of reactive hydrocarbons from the atmosphere by reaction with hydroxyl radicals. Six representative atmospheric hydrocarbons ( hexane, octane, toluene, m-xylene, a-xylene and mesitylene) were selected for these experiments. The experimental data indicated that the decay of atmospheric hydrocarbons under laboratory conditions is entirely due to reaction with hydroxyl radicals. The conclusion drawn from a time-resolved plume study that aromatic molecules decay much faster than could be accounted for solely by reaction with hydroxyl radicals was not verified; this indicates a difference between laboratory study and the study in the real atmosphere, and some physical factors besides chemical mechanism might take a more significant role in removing aromatics faster from the atmosphere.

Studies have shown that some canines have the ability to predict seizures in people with epilepsy, and that canines can be trained to recognize changes in humans before an epileptic seizure and make these predictions. It is not known with any certainty to what the canines are alerting. However, canines’ exceptional sense of smell and their ability to discriminate human scent is well established. Therefore, it is possible that the canines could be responding to an olfactory cue, such as the release of some volatile organic compounds (VOCs) prior to the onset of a seizure. Individuals release a wide array of VOCs, both odorous and non-odorous, from their bodies. The odorous VOCs collectively make up human scent and a number of these VOCs have been identified as biomarkers of different diseases. Evidence suggests that canines can perceive these biomarkers, leading to early detection of underlying physical ailments before individuals are aware of their own symptoms. The main purpose of this study was to use headspace solid phase microextraction (HS-SPME) with gas chromatography-mass spectrometry (GC-MS) to analyze hand odor, saliva and breath samples from epileptic with and without seizure activity to determine if the human scent profiles resulting from a seizure event differs from the scent profiles in the absence of seizure activity. the HS-SPME-GC-MS method was also used to analyze and compare hand odor, saliva and breath samples of healthy individuals and epilepsy patients to determine if the profiles can be differentiated. Comparison of the VOCs in each specimen from healthy individuals and epileptic patients revealed compounds that could be used as potential biomarkers to differentiate between healthy and epileptic individuals. Comparison of the VOCs in each specimen from epileptic patients with and without seizure activity revealed compounds that could be used as potential biomarkers for epileptic seizures. Finally, canine trials were used to verify that these compounds are indeed biomarkers.

Thesis (B.S.) Magna Cum Laude --Butler University, 2009. / Includes bibliographical references (leaf 29).

Methylzinc tetrahydroborate, [MeZnBH₄], has been prepared by two routes and the structure of the solid determined by X-ray crystallography to reveal helical polymers in which MeZn and BH₄ units alternate. The latter functions as a bidentate ligand with respect to each of the adjacent metal atoms. Investigation by mass spectrometry and matrix isolation shows that the vapour consists of an equilibrium mixture of monomeric and dimeric species. The pattern of infrared bands for the monomer is characteristic of a bidentate BH₄ group, a finding consistent with the results of DFT calculations. Disproportionation into [Me₂Zn] and [Zn(BH₄)₂] is a common feature of the chemistry of methylzinc tetrahydroborate, although it has been possible to isolate and characterize the adduct [MeZnBH₄.SMe₂]. The reaction between [B₄H₁₀ and [Me₂Zn] in the gas phase affords colourless acicular crystals of [(MeZn)₂B₃H₇] in yields of ca. 10%. This compound has been characterized by chemical analysis and by NMR and vibrational spectroscopy. X-ray crystallography reveals that the product is a dimer, [(MeZn)₂B₃H₇]₂, featuring two distinct zinc environments. Two B₃H₇ZnNe ligands, formally derived from B₃H₈ by replacement of a µ₂-H by a µ₂-ZnMe unit, each function in a bis(bidentate) manner linking together two other MeZn centres through pairs of Zn-H-B bridges. The structures of several aluminium tetrahydroborates in the solid phase have been investigated by X-ray diffraction. The structure of dimethylaluminum tetrahydroborate has been shown to consist of helical polymeric chains in which Me₂-Al and BH₄ units alternate. Here, too, the BH₄ groups exhibit bidentate ligation with respect to each of the adjacent metal atoms, although the degree of interaction between the metal centre and the BH₄ group is somewhat less than in [MeZnBH₄ ]. Solid aluminium tris(tetrahydroborate) exhibits two phases with a transition temperature in the range 180-195 K. Each phase is made up of discrete Al(BH ₄ )₃ units, the principal differences relating to the packing of the individual molecules. In the a phase the Al(BH ₄ )₃ molecules display an angle of 78.2° between the AlB₃ and Al(µ-H)₂ planes and are disposed about a 2₁ crystallographic screw axis; in the ß phase the molecular units conform to D_3h symmetry. Dimethylindium octahydrotriborate, [Me₂ lnB₃ H₈ ], has been synthesized by the reaction between trimethylindium and tetraborane(10) and characterized by chemical analysis and by NMR and vibrational spectroscopy. X-ray diffraction of a single crystal reveals that the solid consists of [Me₂ lnB₃ H₈] units, although there is evidence of charge separation in the sense [Me₂ln]⁺[B₃ H₈ ]^- and of secondary interaction between terminal hydrogen atoms and adjacent indium centres. The infrared spectrum of the matrix-isolated vapour is consistent with a monomeric structure similar to that of [Me₂ AlB₃ H₈].

No description available.