Includes abstract. / Includes bibliographical references. / Spark Ignition (SI) engine fuels' anti-knock properties are measured in the Co-operative Fuel Research (CFR) engine under two different test conditions as prescribed by the American Society for Testing and Materials (ASTM) for Research Octane Number (RON) and Motor Octane Number (MON) ratings. Recent research has been focused on determining whether the numerical difference between RON and MON, known as Octane Sensitivity (OS), is a result of the chemical or physical properties of the fuel. The present research examined the effect that the operating environment has on fuel evaportion, and thus OS, in the CRF engine.

Includes abstract. / Includes bibliographical references. / X-rays have played a vital role in both the medical and security sectors. However, there is a limit to the amount of radiation a body can receive before it becomes a health risk. Modern low dose x-ray devices operate using a c-arm which moves across the entire human body. This research reduces the radiation applied to the human body by isolating the region that needs exposure. The medical scanner that this work is based on is still under development and therefore a prototype of the scanner is developed for running simulations. A camera is attached onto the prototype and used to point out the regions that are required to be scanned. This is both faster and more accurate than the traditional method of manually specifying the areas.

Includes abstract. / Includes bibliographical references (leaves 147-159). / This study investigates the requirements and implications if South Africa were to evolve its electricity supply structure to a large emphasis on Concentrated Solar Power (CSP). It does this by assessing the local geographical conditions and what are the land, water and radiation requirements of CSP followed by an investigation into the transmission grid requirements. Recommendations are drawn up of possible grid expansion options followed by a comparison of current national expansion plans. Energy storage was pinpointed as being a key to the large scale uptake of CSP where intermittent, solar energy’s capacity factor can be significantly up scaled to suit the national load profile. Storage options were evaluated, assessed and compared after which recommendations were made for immediate and future installations. The other key issue for the national uptake of CSP is sustainable development and the need to cultivate and grow a local design, manufacturing, construction and operations industry centred around CSP. This dissertation looks at the potential employment creation of CSP, along with materials estimates, manufacturing requirements and the skills needed to facilitate the industry.

Bibliography: p. 107-109. / The growing interest in fermentation and fermentation technology as a means to produce chemicals has led to the investigation of different aspects of many fermentations. In this work, the inhibitory effects of the product ethanol on the yeast Saccharomy cescerevisiae ATCC 4126 have been studied during the conversion of the substrate glucose. Continuous culture techniques under anaerobic conditions (the medium was not deaerated) were used where high concentrations of ethanol were produced by the yeast itself. This was in contrast to previous studies in the literature where ethanol was added to the culture.

Includes bibliographical references (leaves 58-59). / Includes abstract. / This thesis is about a new approach to SPH. Instead of using a single kernel or shape function for approximation of a function and its derivatives, individual shape functions are used for each derivative. The investigation is carried out in one space dimension. After producing the conditions for consistency and convergence for the zeroth, first and second derivatives, a new set of linear or piecewise-linear shape functions which meet the minimum of these requirements are presented for each.

Bibliography: leaves 100-103. / The Discrete Element Method (DEM) is a collection of numerical techniques based on a discontinuum idealisation of a physical system. Discrete Element Methods have been successfully applied to the simulation of the dynamic behaviour of granular media. Using the Finite Element Method to model the behaviour of each discrete element has resulted in the Combined Finite Discrete Element Method. This combination allows researchers to investigate the behaviour of assemblies of particles in which each particle need not behave in an entirely elastic mamrer. More importantly, discrete crack constitutive models may now be applied to each discrete element. The purpose of this thesis is to simulate the macroscopic behaviour of an assembly of brittle particles, using the Combined Finite Discrete Element Method. Brittle behaviour is incorporated via the use of a Mode I and Mode II brittle failure constitutive models. The Mode I and Mode II failure models used are the Rankine and Tresca failure models, respectively. The development of a pre-processor to generate the initial configuration of the particle assembly also formed a major component of the thesis. Algorithms to fill a plane with randomly shaped polygons were developed and implemented for the pre-processor. The cold compaction process is idealised as the compaction of a granular medium, in which each particle is a deformable polygon. Two algorithms are proposed and implemented to generate randomly shaped polygons. A further algorithm was developed to fill a simple bounding polygon with smaller polygons. A_commercial CFDEM code, ELFENExplicit, was used to investigate the effect of particle constitutive model and particle interaction on the macroscopic behaviour of the granular assembly. The built-in linear elastic and Mode I Rankine failure models were used in the initial simulations while a Tresca failure model was implemented to investigate the effect of a Mode II failure model.

Includes bibliographical references. / The matte converting furnace s are found at the heart of the copper and nickel smelting processes where oxygen contained in air and industrial oxygen is used to oxidise iron in the furnace matte to produce blister copper or the iron free matte suitable for treatment in the downstream processes. A fundamental knowledge of the base metals matte smelting and converting processes system is valuable for maintaining a stable and optimum process operation. A mathematical model for the Ni - Cu - PGM matte converting process has been developed based on the assumption that the converting process is both in chemical and thermal equilibrium. The converting process demonstrated by the model is the Top Submerged Lance (TSL) base metal continuous converter that treats Ni - Cu - PGM furnace matte similar to the one utilized at one platinum smelter. The TSL PGM converter was chosen for the reasons that the Ausmelt/Isasmelt TSL smelting furnaces are high ly productive flexible smelting and converting units and environmentally friendly, that requires a low capital cost compared to other smelting processes. The model predicts the masses of the process inputs of air, oxygen, fuel coal or oil, silica flux and the outputs components contained in the three product s high grade matte, slag and offgas. The mathematical model utilises the matrix - inverse method that is used to solve the matrix representing a system of several linear equations to give the values of unknown variables. The mathematical matrix - inverse method provides us with the tool to solve many large linear equations arranged in a square matrix numerically to gives solutions. The matrix - inverse method was chosen because it is part of windows excel formulas as MINVERSE and MMULT formulas which is accessible on most computers with Microsoft windows program. The inverse of the matrices is solved using the Gauss - Jordan mathematical method. The study found that the matrix simulation model is able to give accurate predictions of the masses of the industrial TSL converter process inputs fuel, air, oxygen, and silica flux as well as the process outputs masses of the components of converter matte, slag and offgases. The model also indicated that changes in the feed matte composition, moisture in feed , matte feed rate, oxygen enrichment, bath operating temperature and fuel type results in change in one or more of the process inputs requirement and masses and composition of product phases. The simulated model results compare very well with the industrial plant process parameters sourced from one of the platinum smelters that use the TSL technology for converting furnace matte. The results predicted by the model provides good insight into the operations , control and design of the TSL Ni - Cu matte converter and therefore the model is regarded as an invaluable asset for predicting the process dynamics of the present and future converting units. The model provides a good understanding of the base matte converting process and as such will serve as a useful tool in improving and optimising the base metals converting processes without carrying out extensive and expensive tests. It is concluded from the study that the mathematical matrix - inverse calculation method is suitable for modelling the smelting and converting processes of the Ni - Cu - Fe - PGM matte in the TSL converter. The model results were validated through comparison with actual plant operating parameters sources from the relevant platinum smelter which indicated an accuracy of over 9 0% on most parameters. The modelling of the base metal smelting and converting processes has valuably been furthered, however for complete confidence in the model results, further validation is recommended using other simulation softwares and methods.

Image matching is widely considered to be one of the most difficult tasks of a digital photogrammetric system. Traditionally image matching has been approached from either an area based or a feature based point of view. In recent years significant progress has been made in Area Based Matching (ABM) techniques such as Multiphoto Geometrically Constrained Least Squares Matching. Also in the field of Feature Based Matching (FBM) improvements have been made in extracting and matching image features, using for example the Forstner Operator followed by feature matching. Generally, area- and feature based matching techniques have been developed independently from each other. The aim of this research project was to design an automated image matching scheme that combines aspects of Feature Based Matching (FBM) and Area Based Matching (ABM). The reason for taking a hybrid approach is to encapsulate only the advantages of each matching scheme while cancelling out the disadvantages. The approach taken was to combine traditional aspects of ABM in digital photogrammetry with image analysis techniques found more commonly in the area of image processing and specifically machine vision.

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