Theses and dissertations (Engineering and Built Environment)
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Item An analysis of the factors influencing the relationship between soil properties and optimum moisture content and the formulation of an abbreviated test method of determinig maximum dry density(1997) Allinsin, Anthony James; Coetzee, J.The strength and durability of any soil structure is dependent on the quality of the compaction of the soil. This quality is measured by employing a standard compaction test, which provides a standard with which density may be compared, called the maximum dry density, and the moisture content of the soil at which this is achieved, called the optimum moisture content. As a matter of routine during quality control, the particle size distribution, plasticity index and liquid limit of the soil are determined at the same time as its maximum dry density and optimum moisture content.Item Methodologies for the optimal design of fibre-reinforced composite structures(2003) Smith, Ryan Elliot; Walker, MarkComposites have become important engineering materials, especially in the fields of automotive, aerospace and marine engineering. This is due to the high specific strength and stiffness properties they offer. At present, fibre-reinforced plastic (FRP) laminates are some of the most common types of composite used. They are produced in various forms with different structural properties. As with all engineering materials, there is the existence of both advantages and disadvantages. One of the main disadvantages is the expense involved in producing both the material and the finished product. The design time is also costly as the material has to be designed concurrently with the structure.Item Laboratory optimisation of the carbonatation process with regard to colour removal at the Malelane Refinery(2001) Moodley, Manogran; Lionnet, G. R. E.The purpose of this investigation was to identify and then optimise the factors that affect the decolourisation during the carbonatation process. Batch carbonatation tests, carried out in a pilot plant in the laboratory, were performed to establish the effect of selected factors on the decolourisation of melt.Item Cost effective electrical reticulation of the rural areas in Transkei at the district of Lady Frere (Nkolonga)(1995) Booi, Bongani Mpumelelo; Khumalo, J.The purpose of this study is to investigate the most cost effective way of electrifying rural areas in the Transkei concentrating in the district of Lady Frere. One Administrative Area (A.A) was used for research. Questionnaires were send to people of this area where a like rat format was followed. For the purpose of this study, 20 families were randomly selected for investigation.Item An investigation into the development of a portable, ultrasonic, density measuring instrument(1987) Hulse, Nigel Douglas; Stewart, A. B.In the gold mining industry, one of the significant physical properties of the mineral slurry is its density and it is important to be able to measure this parameter in most processes. There are many techniques for determining the density of fluids, but because of the hostile, abrasive nature of mineral slurry, very few of these are suitable, This dissertation describes the deveiopment, construction and testing of a portable, ultrasonic, density measuring instrument. The instrument uses an ultrasonic transducer as the primary measuring element, and system operation is based on the fact that the driving impedance of the transducer varies with changes in the physical properties, and hence the characteristic impedance, of the surrounding medium into which the ultrasonic energy is being transferred. The technique may a-Lao be used to measure the relative concentrations of two liquids in a mixture or emulsion, provided that the characteristic impedances of the liquids are sufficiently dissimilar. The electronic circuitry is fairly straightforward, consisting essentially of an oscillator, driving circuit for the transducer and a voltage monitor to provide a d.c. voltage proportional to the impedance of the transducer, and hence to the density of the surrounding medium. Most of the research has been concentrated on the probe design, as the type of transducer, the type and thickness of facing material and the method of construction all contribute to the sensitivity of the instrument. A design of probe assembly has been developed that may be used for both slurry density measurement and the measurement of the ratio of aqueous to organic liquids in emulsion.Item An investigation into the quality of supply voltage dip-proofing(1998) Lange, Lyle George; Crow, A.With the ever increasing electrical demand on an electrical system, the quality of the supply will be tested more and more. And it is with this deteriorating quality that the topic of voltage dips and depressions has become a contentious issue amounts the industrial sector and supply authorities, hence the means to combat this issue in recent years.Item The development and evaluation of an on-line sugar purity meter for use in a low grade continuous centrifugal(2001) Moodley, Manogran; Pillay, Visvanathan LingamurtiThere are two process operations in the sugar factory that directly affect the recovery of sugar from evaporated syrup, namely crystallisation (boiling) and centrifugal operation. Successful automation of the vacuum pans (boiling) has been implemented using brix (total dissolved solids) control, but to date on-line measurement of continuous centrifugal performance has not been successfully accomplished in South Africa. The purpose of this investigation was to continue the preliminary work performed by Tongaat Hulett Sugar in developing a purity meter for the measurement of sugar purity (sucrose content) in a continuous centrifugal. This instrument would provide the centrifugal operator with a reliable tool to perform on-line measurement of sugar purity and would also facilitate the automation of the centrifugalItem The development of techniques for the analysis of reactive dyes in textile dyeing wastewater(1999) Hansa, Ayesha; Buckley, ChrisAn environmental problem facing the textile industry is the coloured effluent from the dyeing of cellulosic fibres with reactive dyes. Reactive dye loss during dyeing operations is about 10 to 40 %, indicating the need to learn more about the fate of these dyes. Increasing environmental regulations are driving technical innovation to manage this problem. Good analytical techniques for the separation and detection of reactive dyes and their derivatives are necessary for monitoring dye-house effluent, as well as in the optimisation of dye synthesis, purification, formulation and application.Item An investigation into the factors affecting precoat performance in woven-fibre microfiltration(2002) Vallabh, Shadana; Pillay, LingamCrossflow microfiltration (CFMF) using a fabric support has been successfully used to treat a range of problematic waters. Experimental evidence indicates that the formation of a dynamic membrane or precoat on a woven-fibre microfilter can significantly increase the performance of the filter, that is, the production rate and rejection. The use of precoats in filtration applications is based on the precoat's unique microstructure that is able to trap sub-micron particles while maintaining a permeable filter cake. However, to date the precoating step has been more of an art than a science. Very little knowledge exists on the best type of precoat to use, or the the optimal velocity, pressure and concentration to form a stable precoat. Further, although various models have been proposed for CFMF, their still exists a lack of knowledge of the mechanisms by which precoats improve performance.Item Stress evaluation of a monolithic refractory concrete rotary calciner lining for Tioxide Southern Africa(1993) Ilbury, M. W.; Stone, Nigel A.; Coertze, Dirk J.