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This thesis examines turbulent diffusion processes in rectangular and compound open channels, with particular attention to the effect of secondary flow and the relationship between eddy viscosity and eddy diffusivity. Three dimensional velocities and concentration were measured using 3 component Laser Doppler Velocimetry (LDV) combined with Laser Induced Fluorescence (LIF) from three laboratory flumes: one rectangular simple channel and a deep and a shallow compound channel. (Continues...).

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A study of thrust vectoring techniques of annular aerospike nozzles was conducted. Cold-flow blow-down testing along with solid modeling and rapid prototyping technology were used to investigate the effects of slot size, placement, geometry and orientation. The use of slot-type compound nozzles proved to be a feasible approach to thrust vectoring. Previous methods of thrust vectoring have proved to be difficult to implement in a cost effective manner or have had limited effectiveness or durability.

Prior work in this system has indicated that, under favourable conditions, the formation of a martensitic transformation product on cooling may be preceded by a second-order cubic-rhombohedral transformation. In the present investigation, thin film electron microscopy and diffraction have been employed to study the pre-transformation phenomena in the temperature range 20-300°C. The results are interpreted in terms of localized thermal diffuse scattering, resulting from incipient mechanical instability. A model for the cubic-rhombohedral transformation of the rhombohedral phase suggest a moderate degree of co-operation between adjacent domains. Additional data is provided in the form of volumetric and x-ray intensity measurements. / Thesis / Master of Engineering (ME)

Survey work has resolved certain reported anomalies in this system. In particular, TiNi was found to undergo two displacive phase transformations at temperatures near room temperature. Below 50°C the pseudo body-centered cubic compound undergoes a gradual distortion in an unusual second order phase transformation producing the "transition phase”, the existence of which is terminated by a typical martensitic burst transfor­mation at 20°C which produces the "martensitic phase". The crystal structures of the parent phase and transformation products, and the trans­formation characteristics have been studied with X-ray and electron diffrac­tion, electron microscopy, electrical resistance and density measurements. / Thesis / Master of Science (MS)

The search for structural fragments (substructures) of compounds is very important in medicinal chemistry, QSAR, spectroscopy, and many other fields. In the last decade, with the development of hardware and evolution of database technologies, more and more chemical compound database applications have been developed along with interfaces of searching for targets based on user input. Due to the algorithmic complexity of structure comparison, essentially a graph isomorphism problem, the current applications mainly work by the approximation of the comparison problem based on certain chemical perceptions and their search interfaces are often e-mail based. The procedure of approximation usually invokes subjective assumption. Therefore, the accuracy of the search is undermined, which may not be acceptable for researchers because in a time-consuming drug design, accuracy is always the first priority. In this dissertation, a design of a search engine for chemical compound database is presented.The design focuses on providing a solution to develop an accurate and fast search engine without sacrificing performance. The solution is comprehensive in a way that a series of related problems were addressed throughout the dissertation with proposed methods. Based on the design, a flexible computing model working for compound search engine can be established and the model can be easily applied to other applications as well. To verify the solution in a practical manner, an implementation based on the presented solution was developed. The implementation clarifies the coupling between theoretic design and technique development. In addition, a workable implementation can be deployed to test the efficiency and effectiveness of the design under variant of experimental data.

The mantis shrimp Gonodactylus oerstedii is known to possess eyes capable of colour and polarised light vision. The apposition compound eyes of these creatures are highly mobile and their ommatidia are specialised to analyse the spectral and e-vector qualities of light in a central strip of the eye called the midband. The retina of the midband of Rows 1-4 is tiered with each row being sensitive to a narrow region of the colour spectrum. Row 5 and 6 ommatidia possess many structural features designed to allow the e-vector direction of light to be detected. This thesis investigates the neuroanatomy in the neuropile regions below the retina in an attempt to elucidate the mechanisms which allow colour and polarised light vision to take place. In Chapter 2 the retina-lamina projection of the retinal axons is studied in an ommatidium in Row 3 of the midband, and the findings suggest that the stomatopod is similar to all other crustacea so far studied, despite its unusual retina. Chapter 3 investigates the neuroanatomy of the medulla neuropile regions. A novel region of the medulla externa which deals with colour information is discovered. In Chapter 4 the lamina of Rows 1-4 is looked at in more detail, with the number of monopolar cells and the detailed arrangements of the retinular cell terminals being ascertained. The terminals sensitive to different regions of the spectrum are located in different areas of the lamina cartridge. Chapter 5 looks at many of the issues above but this time in relation to rows 5 and 6 of the midband, which are specialised for polarisation vision. The lamina neuropile is very different to that of Rows 1-4 and again a specialised region of the medulla externa is found which processes information from these rows. This thesis provides evidence that the optic lobes of Gonodactylus oerstedii are comparable to other crustacea but nevertheless may possess some intriguing specialisations related to their extraordinary colour and polarised light vision.

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

published_or_final_version / abstract / Physics / Master / Master of Philosophy