Includes bibliographical references. / Over the past two decades significant advances have been made in the areas of engineering (design) and technology (implementation and operation) of the single sludge activated sludge system. Activated sludge systems have been successfully designed and implemented at full-scale for the biological removal of carbon (C), nitrogen (N) and phosphorus (P). This implementation has been aided by the development of a suite of steady state design models (e.g. WRC, 1984; Wentzel et aI., 1990; Maurer and Gujer, 1994) and kinetic simulation models (e.g. Dold et al., 1980, 1991; Van Haandel et aI., 1981; Henze et al. , 1987; Wentzel et aI., 1992; Henze et al., 1995).

Includes bibliographical references. / Synthetic Aperture Rada Interferometry (InSAR) is a relatively new remote sensing technique, which can be used to derive precise topographic height change information over large areas. It is a technique which has been used in a great variety of situations, from the topographic mapping of Venus to the detection of subtle ground deformations due to earthquakes and mining subsidence. The InSAR technique involves using the phase information inherent in radar images to extract elevation and elevation change information. The process requires very careful co-registration of a pair of complex images of the same scene, followed by the multiplication of the one image by the complex conjugate of the other. In this manner, a phase difference image, or interferogram is generated, in which subtle differences in the distances from the two imaging sensors to the ground are mapped, thereby making it possible to generate a height model of the ground surface. An extension to the InSAR technique, is that of difference image, or interferogram is generated, in which subtle differences in the distances from the two imaging sensors to the ground are mapped, thereby making it possible to generate a height model of the ground surface.

Includes bibliographical references (leaves 127-135). / Eco-efficiency has been proposed by the World Business Council for Sustainable Development as a performance indicator framework that contributes to sustainability by assisting corporate decision makers improve the environmental performance of their operations and processes, while also extracting additional economic value. Given the emergent importance of eco-efficiency within the business community and the urgency with which environmental impacts generated by the minerals industry need to be mitigated, it becomes apparent that there is a need to assess whether eco-efficiency indicators can drive environmental sustainability performance improvement during process design within the minerals industry. This thesis aims to respond to this research need by assessing the strengths and limitations of eco-efficiency indicators as performance metrics in guiding decision making during minerals process design in the interests of environmental sustainability. The ultimate aim of this thesis is to contribute towards improved guidance for process design engineers in the selection of the appropriate tools for more environmentally sustainable design of minerals beneficiation processes.

Includes bibliographical references. / Wrought Ti6Al4V has attractive mechanical properties but its usage is limited to highend aerospace applications because it is costly to machine components from wrought stock. Investment casting is an alternative component manufacturing route but cast components have inferior mechanical properties to their wrought counterparts. Therefore, microstructure refinement is required in order to optimize these mechanical properties. The aim of this work is to refine the as-cast Ti6Al4V microstructure by reducing its prior beta grain sizes and changing its Widmanstatten morphology. Refinement was achieved through combining thermohydrogen processing (THP) and hot deformation.

Includes bibliographical references (leaves 280-293). / Energy is a very important resource for national development. Uganda's energy mix comprises mainly biomass, petroleum products and electricity. Biomass is the main source of energy, contributing 92.3%. Petroleum contributes 6.3% and electricity 1.3% of the total energy consumption. The contribution of other forms of energy; wind, solar energy and biogas is negligible. Biomass is mostly used in households and small-scale industries. Petroleum and electricity are used in large-scale industries and in the commercial sector. It was envisaged that this study will be an important input into the National Vision, developed by the Ministry of Finance Planning and Economic Development, for the national development to the year 2025.

Includes abstract. / Includes bibliographical references (p. 109-116). / This study utilised laboratory batch flotation tests to characterise the flotation performance, with respect to sulfide and gangue minerals, of two Merensky ores with different mineralogy, in the presence of depressants; and contributes to the increased understanding of depressant behaviour in the flotation of Merensky ores. The ores were obtained from the southern section of the Merensky reef in the Bushveld Igneous Complex.

Includes abstract. / Includes bibliographical references. / The FT synthesis has been used predominantly for production of automotive fuels. This has made the financial benefit from the FT process heavily reliant on crude oil prices. Increasing the financial viability of the process has been achieved by improving production methods, production of alternative products such as waxes, lubricants, as well as valuable chemicals such as olefins and oxygenates. In an attempt to produce additional chemicals in the FT reaction, this work investigates the synthesis of nitrogen containing compounds via ammonia addition to a low temperature, low pressure, slurry reactor using an unsupported, potassium-promoted, precipitated iron catalyst. The process is subjected to various ammonia contents in the feed.

The Integer Discrete Cosine Transform (IDCT) and Hadamard transforms are adopted in the H.264/AVC standard encoder for the compression of residual video signals. Other video standards such as the H.261, H.262 and H.263 use Discrete Cosine Transform (DCT).

Includes bibliographical references. / This thesis presents work completed on the design of the modelling and path planning components for a robot manipulator mounted on a mobile platform. This platform is for use in the mining safety inspections of the mine roof, i.e., the hanging wall. Currently this process is done by mine workers and it places them at risk of falling of unstable rocks from the roof. A geometric based inverse kinematics algorithm for a 5 DOF redundant manipulator is proposed and implemented on a Packbot510i used as a test platform. Three versions of the Rapidly-exploring Random Trees planning algorithm namely, basic RRT, RRT Ball and RRT_ are compared. Results obtained show that RRT_ is more suitable than RRT and RRT Ball in terms of the length and the consistency of the trajectories produced. A Force Angle stability measure is used to guide the robot arm into trajectories that prevent the robotic system from tipping over. Results show that the Force Angle stable measure is more cautious, i.e., it classifies trajectories close to the instability of the system as unstable. Simulation results provided show that this system is capable of carrying out the safety inspections of the roof in the mining environment. Experimental results show that a few modifications are required for the system to be used practically on the test platform due to issues experienced with the hardware.

Includes abstract. / Includes bibliographical references. / The objective of the dissertation is to compare various algorithms for rate-independent single-crystal plasticity restricted to the infinitesimal case. The rate-independent case presents significant numerical challenges such as ill-conditioning and non-smoothness. The majority of the algorithms in the literature are heuristic and their accuracy, stability and performance not immediately clear. Other algorithms are more mathematically sound but computationally inefficient. This dissertations aims to provide a clear understanding of the algorithms, their implementation within a non-linear finite element code, and a comparison of the computational efficiency.