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The aim of the study was to heterogenise existing tetramerisation catalysts by supporting the bis(diphenylphosphino)amine ligands on polymer. The polymer of choice was Merrifield’s resin which was functionalized to enable attachment of the ligands. These supported ligands were characterized via ATR, solid-state NMR, SEM and TGA-DSC. In order to compare activity of the supported and unsupported ligands, homogeneous bis(diphenylphosphino)amine ligands were synthesized and characterized via NMR, elemental Analysis, ATR and GC-MS. Tetramerisation reactions were carried out in a Parr pressure reactor using Cr(acac)₃as the precursor and MMAO-3A as the activator. The homogeneous ligands proved active in the tetramerisation of ethylene, with the selectivity of 1-octene in the C8 fraction being comparable with that mentioned in literature (> 98 wt%). When comparing the homogeneous ligands with their heterogeneous counterparts, the heterogeneous ligands performed poorly due to steric effects caused by the polymer chain. The activity dropped by more than four times that of their homogeneous counterparts and the selectivity towards the main product, 1-octene, was very low (< 10 wt%). These ligands seemed to create a system that favoured the formation of the C6 products more than any other product, with the C6 cyclics being the most dominant. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2010.

A premixed gaseous rocket injector was designed and successfully operated over a limited range of fuel-rich operating conditions for the purpose of soot modeling for ethylene and oxygen mixtures. The injector had the advantage of delivering a homogenous mixture to the combustion chamber, lower soot production, and higher performance potential by removing the fuel atomization process which affects the combustion process and is inherent for non-premixed injectors. The premixed injector was operated at oxygen-fuel ratios from 1.0 to 1.8 with a mass flow of 0.024 kg/sec achieving a chamber pressure of 76 psi without propensity of flashback for 0.032[gamma] injector orifices. Increased mass flow rates of 0.027 kg/sec were achieved by increasing the injector orifice diameters to 0.0625[gamma] which produced a chamber pressure of 127 psi and a characteristic exhaust velocity efficiency of 90.1 %. Flashback was eventually observed at an oxygen-to-fuel ratio of 1.2 where the pressure drop was across the injector was less than 388.6 kPa and the bulk mixture velocity through the injector orifices was approximately 90 m/s. Maintaining bulk velocity sufficiently above this value should prevent flashback from occurring, but will likely need to be characterized for additional orifice diameters and pressure differentials. / Funded by: SEinc307.

The thesis describes the characterisation and application of the laser induced incandescence technique for making soot measurements in practical devices. Laser induced incandescence is the phenomenon whereby particulates such a soot absorb laser radiation and are heated to a temperature much higher than the bath gas. The broadband incandescence signal from the hot particles can be detected and the signal is proportional to volume fraction. The technique was used to study soot in partially premixed counterflow ethylene air flames, iso-octane explosion flames, and to image soot in a D. I. Diesel engine. Mie scattering, OH-LIF and absorption were used a complementary diagnostics. Appropriate ratios of LII and Mie images allowed the relative particle size and number density to be imaged. The counter flow burner measurements were used to study the effects of strain on soot formation while the bomb work demonstrated soot production in hydro-dynamically unstable cellular flames. The Diesel engine measurements are a demonstration of optical diagnostics in a real device. In order to characterise the LII signal behaviour two types of carbon aerosol generators were built. The liquid dispersion device produces almost spherical sub-micron carbon black particles. The device was used to characterise the soot field response, laser fluence response, signal decay and spectrum of the LII signal.

Thesis (M. Phil.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

Thesis (M.Ch.E.)--University of Delaware, 2009. / Principal faculty advisor: Mark A. Barteau, Dept. of Chemical Engineering. Includes bibliographical references.

Thesis (M. Phil.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 92-101).

Thesis (M. Sc.)--University of Hong Kong, 1955. / Type-written copy. Includes bibliographical references (p. 54-55).

published_or_final_version / abstract / toc / Botany / Master / Master of Philosophy