Includes abstract. / Includes bibliographical references. / This dissertation describes the design and implementation of a mechanism that automates gateware device detection for reconfigurable hardware. The research facilitates the process of identifying and operating on gateware images by extending the existing infrastructure of probing devices in traditional software by using the chosen technology.

Includes bibliographical references (leaves 83-86). / The main objective of this research is to investigate the impact of using GIS and 2.5D modelling in automating the process of determining view factors for CAMA modelling. Five metre contour data is used to generate digital terrain models (DTM) in the TIN data structure and in the raster data structure. The two terrain surfaces are assessed for accuracy by using the Town Survey Marks (TSM) height data.

Bibliography: leaves 79-94. / South Africa is experiencing an HIV/AIDS pandemic of shattering dimensions. The availability and provision of antiretroviral drugs could bring relief to the situation. Different patients use different antiretroviral therapies that vary in complexity of dosage and administering and monitoring the patient-medication related data are complicated tasks. The lack of physical infrastructure, lack of reliable statistics and the lack of adequate resources hinder the efficient management of HIV/AIDS. The purpose of the study is to design and develop an HlV/AIDS database, which is embedded in a Spatial Information Management System. The functions of the system are to properly collect and administer HIV/AIDS related information and locate the HIV/AIDS patients and the proximity of these patients to existing infrastructure in view of providing a spur to improve health care service and delivery. The pilot study area is the Gugulethu township in Cape Town where more than 27% of the 325 000 residents are HIV+. Microsoft® Access is the chosen software for the design of the HIV/AIDS database. Interfaces are customized where the user can view, sort, manipulate and retrieve accurate information on all patients, which has been collected by therapeutic counsellors. By integrating the database within a spatial information system it is also possible to combine patient information with geographic information such as the location of various health care centres and existing infrastructure. It is shown that the implementation of the HIV/AIDS database and the Spatial Information Management System can play a critical role in determining where and when to intervene, improving the quality of care for HIV+ patients, increasing accessibility of service and delivering a cost-effective mode of information.

Includes abstract. / Current concrete specifications used in mix design are mainly of the prescriptive type, i.e.recipe-based specifications that prescribe limiting values for certain mix design parameters such as minimum binder content, maximum water/binder (w/b) ratio and minimum compressive strength class. This has numerous economical, technical and environmental disadvantages and is one of the driving factors behind the development and promotion of performance-based specifications. These have the potential to lead to alternative methods of mix design to improve concrete structural performance. In South Africa, the use of the Durability Index Approach in performance-based specifications has grown increasingly. Durability can be thought of as a materials concept for a structure in a given environment for the duration of its design life. As such, it can only be accurately described by considering it as a function of numerous intrinsic and extrinsic interrelated factors. Despite this, a dominant assumption in the industry is that concrete durability is directly proportional to its binder content and compressive strength, largely due to the misinterpretation of prescriptive specifications in depicting factors like binder content as the governing parameter of durability. This results in uneconomical and often non-durable concretes due to implications of high cement contents, such as high costs (cement is the most expensive constituent of concrete), high shrinkage, thermal effects and alkali-silica reactions. This thesis presents a study on the influence of parameters of mix design, such as w/b ratio, binder content, binder type and curing regime, as well as compressive strength, on the durability of concrete as expressed by the Durability Index Approach. The objective of the investigation was to identify the issues behind specifications of minimum binder contents, as well as identify relationships between mix design parameters, compressive strength and durability indices. This was done by obtaining findings which would serve as a basis to potentially bring about sensible and justifiable changes to specifications. This could in turn lead to more durability-oriented mix design strategies. In order to verify whether prescriptive specifications such as minimum binder contents are justifiable, various studies in literature were reviewed on the subject. In the literature review, it was identified that certain relationships exist between aspects of concrete durability and various parameters, among which are binder content, w/b ratio and compressive strength. It was found that the nature of these relationships cannot be generalised as each relationship needs to take into consideration a variety of additional influencing factors. One example is that the influence of increasing binder content on durability indicators is often detrimental and can seldom be associated with beneficial effects. This is because there are other factors such as increasing paste volume that need to be considered.

Includes bibliography. / Mine warfare is a very effective method of warfare as it has the element of surprise, it doesn't require interaction with the enemy, and it has a high percentage of fatalities. Because of this, mine warfare has been used extensively across the world during conflicts and therefore there is a need for mine-detecting and mine-protected vehicles. The systems of protection of these vehicles need to be investigated so that they can be optimized. The study in this document investigates the effect of a disc of high explosive on a steel V-shaped plate through numerical modelling. This system is a simplified simulation of a mine detonating beneath the V-shaped hull of a mine-protected vehicle.

This dissertation outlines the development of a parallel 3D hybrid finite-volume- finite-difference solver. As motivation for such a scheme, the specific application area under consideration is modeling the trailing vortices shed from the wings of aircraft under transonic flight conditions. For this purpose, the Elemental® finite volume code is employed in the vicinity of the aircraft, while the Essense finite difference software is employed to accurately resolve the trailing vortices. The former method is spatially formally 2nd order and the latter set to 6th order accurate. The coupling of the two methods is achieved in a stable manner through the use of Summation-by-Parts operators and weak imposition of boundary conditions through Simultaneous-Approximation-Terms (SBP-SAT). Accordingly, a special parallel SBP-SAT interface library is developed in Elemental®. In addition, the code is extended to impose boundary conditions in a weak manner via the SBP-SAT framework; as well as interface volume definitions changed to allow coupling with the 6th order code. The developed hybrid solver is successfully validated against analytical test-cases. This is followed by demonstrating its ability to model the flow field, including trailing vortex structures, around the NASA Common-Research-Model (CRM) under transonic flow conditions. Inviscid flow was assumed and the trailing vortices from both wing and horizontal stabiliser accurately resolved to 3 and 1 reference chords downstream of the lifting surface respectively. The robustness of the interface treatment is demonstrated by the smoothness of the flow solution across an interface boundary in the presence of high flow gradients and rapidly changing mesh topology. In addition, high vortex axial flow gradients were predicted while the vortex core speed is 6 % slower than free-stream.

In the context of a growing world population, more sustainable solutions for energy generation are required. Fuel cells supplied with hydrogen generated from fuel processing trains have emerged as a potential medium-term solution due to their improved efficiency and lower greenhouse gas-emissions. This study focuses on the development of a compact, efficient design for fuel processing trains. More specifically, reduction in the size of the largest component, the Water Gas-Shift (WGS) reactor, which could be achieved by an increase in the catalytic activity via alternative catalyst synthesis techniques. Solution combustion synthesis (SCS) is one such technique that could be used since it allows for the preparation of highly-dispersed Pt oxide particles on low surface area CeO2 with a reproducible metal loading and a defined Pt particle size. The aim of this study was to investigate the “conventional” impregnation approach of supports prepared via SCS versus the one-shot SCS approach (support and active metal prepared in one step) for the synthesis of 1 wt.% Pt/CeO2 catalysts for the WGS reaction using a reformate feed stream. It was hypothesized that the preferential formation of metallic Pt species supported on CeO2 can be achieved using a glycine-nitrate combustion system with excess glycine fuel (stoichiometric ratios of glycine to nitrate oxidants > 1) i.e. the Pt is reduced during the one-shot SCS approach. The catalysts were characterized by XRD, N2-physisorption, ICP-AES, TEM and XPS, and their activity towards the WGS reaction was evaluated with a synthetic reformate stream (50 % H2, 6.67 % CO, 6.67 % CO2, 33.3 % H2O, 3.36 % He). Initial characterization results of the catalysts prepared by the one-shot SCS approach confirmed the reproducible synthesis of Pt particles supported on nano-sized CeO2 with low surface areas. Furthermore, TEM and XPS results of the one-shot SCS prepared catalysts indicated that the Pt species were mainly present as Pt oxide particles on the surface of the CeO2 supports. However, for combustion systems with excess fuel, formation of some metallic Pt was observed together with the more prevalent Pt oxide particles. The catalysts prepared by the “conventional” impregnation approach had higher activities towards the WGS reaction than the one shot SCS catalysts. This was attributed to the smaller Pt particles achieved using this “conventional” synthesis approach (approximately 1 nm compared to 3 nm). One-shot SCS is a viable synthesis approach for the preparation of 1 wt.% Pt/CeO2 catalysts as this method allows for the preparation of highly-dispersed Pt oxide particles on low surface area CeO2 with a reproducible metal loading and a defined Pt particle size. However, the characterization results indicated that using a combustion system with excess fuel resulted in the preferential formation of Pt oxide phases as opposed to the desired metallic Pt phase, therefore refuting the hypothesis of this study. Nevertheless, it is recommended to repeat the synthesis of the 1 wt.% Pt/CeO2 catalysts in an inert atmosphere as this has shown to favour the formation of metallic species (Cross et al., 2014). This study was unsuccessful in preparing catalysts using a glycine-nitrate one-shot SCS system that were more active than the “conventionally” prepared catalysts. However, it is recommended that other fuel types, such as urea, also be investigated. These alternative fuel types could combine the good Pt dispersion achieved using the one-shot SCS approach with potentially smaller Pt particle sizes, thereby increasing the catalyst’s activity towards the WGS reaction (Vita et al., 2015a).

Passive Coherent Locator (PCL) radar’s have seen extensive research in the past decade. PCL radars utilize illuminators of opportunity (IOO) as transmitters to perform target detection. Particular interests in FM (analogue) and DVB-T/T2, DAB (digital) radio frequency signals has seen significant focus as possible illuminators for radar processing. The University of Cape Town (UCT) , in particular, has extensive history on passive radar research including the implementation of a full narrowband FM PCL radar demonstrator. This dissertation details the design and implementation of a DVB-T2 Passive Coherent Locator radar demonstrator isolating a single DVB-T2 channel. This includes the design, construction, testing and evaluation of the full PCL radar system. System planning was implemented detailing the possible IOOs available in the Cape Town area. This was followed by signal propagation simulations to determine the effects the environment would have on the transmitted wave utilising Advanced Refractive Effects Prediction System (AREPS) model. A front-end design was simulated and implemented utilizing commercial-of-the-shelf (COTS) hardware including the National Instruments Ettus N210 software defined Radio (SDR) based on the system planning results. A processing chain for DVB-T2 based PCL radar was then investigated to determine the most optimal processing chain structure, with the mismatched filtering technique being proposed as an ideal choice for DVB-T2 PCL radar. The proposed processing chain was implemented and tested on both the Ettus N210 front-end as well as a commercial system. The full radar demonstrator was then tested by observing the air traffic surrounding the Cape Town International airport resulting in successful detections of aircraft in the surveyed environment.

Bibliography: leaves 74-76. / Automatic generation control (AGC) is the centralised short-term closed-loop control (regulation) of generating units in a control area. The main objectives of AGC are to maintain the system frequency at 50 Hz; to obtain correct tie-line interchange; and to operate each generating unit at its most economic value. The cost of operation of a regulating (moving) generating unit is, however, higher than that of the same unit being used at a fixed output. Primary energy cost as well as longer-term maintenance cost and life expectancy is affected by regulating generating units. With the continuous drive to reduce costs, the question was raised whether the amount of regulation done by AGC is justified. The original AGC system could not be set up to achieve the required quality of supply while using the minimum control expected. An enhanced design of load following and distinctive ACE regulation was developed and implemented. Although the load-following component of the original controller could be applied with minor modifications, the short-term ACE regulation component had to be improved significantly. The main alterations involved the addition of a derivative component by means of fuzzy logic and the elimination of nonlinearities from the control. This research describes the enhanced design developed to obtain the required performance while minimising the control effort.

Includes abstract. / Includes bibliographical references. / Of the various types of fuel cells, Polymer Electrolyte Fuel Cells (PEFCs) have already been demonstrated in transportation appliances from light-duty vehicles to buses and in portable appliances including laptops and cell phones. A key component of a PEFC is its platinum electrocatalyst. With an estimated 75% of the world’s platinum reserves and resources in South Africa, local development of this technology will allow South Africa to become a major player in the growing hydrogen economy. This project therefore forms part of the Department of Science and Technologies strategy, to develop fuel cell technology in South Africa. More specifically, this study aims to contribute to the development of membrane electrode assembly (MEA) platform technology at the HySA/Catalysis Centre. In order to achieve this goal, a catalyst coated membrane (CCM) fabrication procedure was implemented using a newly acquired screen printer. In this procedure, catalyst ink is forced through a mesh onto a substrate, where it can then be transferred to a membrane via decal transfer to form a CCM. Two gas diffusions layers can then be placed on either side of the CCM forming a 5-layered MEA. Characterisation techniques of the catalyst ink, CCM and 5-layered MEA were successfully implemented such that future researchers can expand on the ideas. Catalyst inks with varying amounts of isopropanol, 1,2-propanediol and water were screened for their suitability for screen printing. In particular the catalyst ink rheology required for a smooth and even printed surface was determined for a given screen and squeegee combination. With all the established steps in pace, screen printing proved to be a fast and reliable approach for CCM fabrication with potential for future scale up and commercialisation. The fabricated CCMs performed on a par with a commercial Ion Power CCM, but under performed in comparison to a commercial Johnson Matthey (JM) MEA. Possible reasons for this include improved materials in the JM MEA and cell conditions favouring the JM MEA. Future projects which specifically arise from this work entail an investigation into the water management of the fuel cell environment at HySA/Catalysis, as well as a modification of the various steps in order to optimise the process and in doing so manufacture commercially viable MEAs.