Wits Institutional Repository on DSPACE

    Biological hydrogen production using an anaerobic fluidised bed bioreactor

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    Faculty of Science School of Molecular and Cell Biology 9904041r lthompson@csir.co.zaThe production of H2 was monitored using an automated, semi-continuously fed anaerobic fluidised bed bioreactor containing 2 facultatively anaerobic bacteria, Enterobacter cloacae (E. cloacae Ecl) and Citrobacter freundii (C. freundii Cf1). Shake flask tests using Endo formulation with modified C:N:P ratios, showed that a 334:28:5.6 ratio gave the highest attached counts of E. cloacae Ecl and C. freundii Cf1 in both single and binary species biofilms grown on granular activated carbon. Once the reactor had achieved steady state after 30 days using the modified C:N:P ratio, pH, redox potential, temperature, volatile fatty acids and the H2 production rate were monitored. The H2 production rate of 95 mmol H2 / (l x h) compared favourably with previous studies. Bacterial biofilms counts for both E. cloacae Ecl and C. freundii Cf1 remained high around 9.0 log cfu/g granular activated carbon, although biomass overgrowth could not be controlled in the reactor. The efficiency of converting sucrose into H2 was calculated at 20.5%. Therefore use of this technology to power a 5.0kW proton exchange fuel cell for a single rural household is currently not feasible due to the high organic load required. Pooling of wastewater generation capacity, improvement of bacterial strain selection and feed formulation, pH control, gas removal and purification are factors that need to be considered for future improvement of conversion efficiencies. Use of this technology would be most suited for industrial processes generating large volumes of wastewater high in carbohydrates. Alternatively, municipal wastewater treatment facilities could be converted into electricity generating facilities through the combination of this technology and proton exchange membrane fuel cells

    Design and Validation of an Arterial Pulse Wave Analysis Device

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    Student Number :9900127Y - MSc (Eng) dissertation - Faculty of Engineering and the Built EnvironmentArterial pulse wave analysis studies the wave shape of the blood pressure pulse. The pulse wave provides more information than the extreme systolic and dia- stolic pressures, measured with a cuff sphygmomanometer. The aim of the research is to investigate the design issues in a pulse wave analysis system, and to compare these to a commercially available system. The system was compared and validated by measuring the pulse wave at the radial artery (wrist) using the non-invasive technique of arterial tonometry. The design conformed to the IEC-601 safety standard to ensure patient safety. The data was compared against the data from the commercial system and analysis was performed in the time and frequency domain. The performance of the design suggests that, in some respects, the design was comparable to the commer- cial system, however, a number of performance characteristics fell short of the commercial system. Suggestions have been made to address these problems in further research

    A review of policy and legal framework to promote Zimbabwe's competitiveness in the mining sector

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    Faculty of Engineering and Built Enviroment School of Mining Engineering 0405669f Willis.Saungwame@bhpbilliton.comThe Republic of Zimbabwe is a landlocked country located in the southern part of the continent of Africa, between the Victoria Falls, Zambezi River, Kariba Dam and Limpopo River. It is surrounded by South Africa to the south, Botswana to the west, Zambia to the north and Mozambique to the east. The country is well endowed with mineral wealth and has been a reputable contributor to the region’s gold, coal, nickel and chromium production in the late 90’s, but this has negatively changed for the worse. Since 2000, Zimbabwe has been on economic recession resulting in growing global interest in the country’s economic and social environment. The lucrative mining sector has also been adversely affected by the harsh economic climate hence thwarting flow of foreign direct investment (FDI) into the country which is needed to boost Greenfield and Brownfield competitiveness in the sector. Apart from its lucrative mining sector the country has done very little in harnessing the anticipated FDI that should ensue. Concerns about governance, the rule of law and human rights, and the continued lack of clarity about property rights have severely damaged confidence, discouraged investment, and promoted capital flight and emigration, thus contributing to the economic decline. Its competitiveness in attracting FDI has since declined because of the international perception of the country’s high political risk. The country has failed to live up to expectations with regards to mineral resource development in the region. The research established that, governance issues are at the helm of the current low performance of the economy. It therefore prescribes a complete change in government’s attitude and calls for it to develop a long overdue mineral policy document to map a strategic way forward for the country’s mineral resource development. Interestingly the country has been hailed to have one of the most liberal mineral administration laws through the Mines and Minerals Act of 1996. Its fiscal incentives to the mining sector compare favourably with the rest of the region e.g. a corporate tax of 15% for exporting mining companies and currently most gold operations are royalty exempt among others. There is a growing divergence from iv policies to actions on the ground. The rule of law is under threat and corruption has taken its toll. It is therefore important for this research to analyse the historical performance of the country in the mining sector to formulate policies and recommendations that will improve the country’s competitiveness in the sector. The policy and fiscal incentives should continuously be revisited to be in tandem with global developments. The endowment theory, strongly believed by the country’s mining ministry as illustrated by Tilton in 1992 is not conclusive in attracting FDI especially in this dynamic global economy. More and more developing countries are revising their investment policies to try and improve competitiveness of their investment environments. Zimbabwe should emulate countries like Chile currently leading the pack in attracting FDI in the mining sector. There is now fierce competition in attracting investment into a country because now, the investor has more countries to choose from. Zimbabwe should seriously focus on getting rid of all the negative aspects that have seriously affected its economic performance and quickly develop policies that auger well with regional integration and various other NEPAD, SADC and AU policies that underpin African development. The mining sector is a driver for economic development if properly supported as shown within the research

    A Software Reuse Paradigm for the Next Generation Network (NGN)

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    MSc thesis - Faculty of EngineeringService creation in the Next Generation Network (NGN) is focused around software creation and borrows heavily from the Software Engineering community. In the NGN, telecommunication companies demand simple, rapid and economical service creation. The key to this type of service creation is software re-use. Software re-use is a conundrum where limited, dedicated solutions exists. These solutions include amongst others Enterprise JavaBeansTM (EJBs), design patterns and object-oriented programming. The Telecommunications Information Networking Architecture- Conformance And Testing (TINA-CAT) workgroup has done work on a functionality centric concept called RP-facets. This report proposes a redefinition of RP-facets, as Facets, for software re-use across the design and code level. We redefine Facets as functionality centric reusable components. A Facet is independent of the implementation language and the execution platform. Facets allow containment in a structured manner via a user defined Facet Hierarchy. Facets are resource, context and data agnostic. They also introduce a structured way to allow source code to be changed based on design level decisions. Also, possessing the ability to allow the simultaneous use of other reuse solutions and programming paradigms. Abstraction of detail from developers and platform migration can be achieved by using Facets. Facets are composed of a Generic definition and any number of Implementation definitions. The definitions are supported by an underlying informational model called meta-¼. Meta- ¼ is a model at the M3 meta-level that focuses on describing entities. Most of the Facet’s capabilities are enabled by the meta-¼ model. An environment for developing Facets is created, called the Facet Development Environment (FDE). The Facet Developer (FD) role is introduced to develop and maintain Facets. The FD verifies programmes from programmers to be included into the catalogue of Facets via the FDE. The FD interacts with service creation teams to determine which Facets can be used in the service they wish to develop. Facets prove their capability in targeted areas, yet lack in other categories. It is recommended that the underlying informational model should be revised to form a more robust and flexible entity describing model. In addition, a cataloging capability to easily find Facets with particular functionality should be appended to the capabilities of the facet. It is proposed, for future work, that a development environment be created that encompasses a process for using Facets to create services

    Evaluation and Design of Affordable and Novel HIV-1 Drug Resistance Assays:

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    Faculty of Health Sciences, Master of Science in Medicine, 9803855eApproximately 5 million individuals are infected with HIV/AIDS in South Africa. The South African government has initiated a National Anti-retroviral therapy (ARV) Program to manage this disease. The emergence of drug resistance to ARV therapy is of great concern. Commercial gold standard sequence-based genotyping assays for monitoring resistance are unaffordable. This project aimed at developing affordable methods to detect specific point mutations relevant to HIV-1 subtype C. The Oligonucleotide Ligation assay (OLA), a real-time PCR assay and a Restriction Fragment Length Polymorphism (RFLP) assay were explored. Results were compared to the Viroseq genotyping assay. OLA performed poorly on HIV-1 subtype C samples and needs modification. The real-time PCR assay using short Minor Groove Binding probes, accurately detected the K65R mutation. The Mae III RFLP assay detected all V106M mutations accurately. Longitudinal cohort studies are required to confirm relevant mutations, appropriate assays and algorithms for resistance monitoring in HIV-1 subtype C

    Tuberculosis and compensation: A study of a selection of Basotho mineworkiers from Maseru district

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    Student Number : 0105964W - MPH research report - Faculty of Health SciencesThe Employment Bureau for Africa (TEBA Limited) established in 1902 recruits mineworkers from Lesotho and neighbouring countries for South African mines. Information on mineworkers’ health and welfare from Lesotho is scarce. Tuberculosis prevalence ranged between 159/100000 and 506/100000 from 1991 to 2001 in Lesotho. This cross-sectional study aimed to determine the proportion of mineworkers affected with tuberculosis among adult male patients attending TB clinics in Maseru District’s three main hospitals and ascertain compensation of mineworkers affected by occupational lung disease including tuberculosis. A structured questionnaire was used to interview 421 adult male TB patients at Queen Elizabeth II, Saint Joseph and Scott hospitals in Maseru. 38.5% of participants in the study were mineworkers (former and active) in South African mines. Among these mineworkers, 70.4% were employed in goldmines. 30.7% of mineworkers were considered eligible for compensation. 42 mineworkers received compensation for previous and current tuberculosis whilst 33 mineworkers had not

    Legal aspects of corporate governance in the republic of South Africa: towards a possible model for improved stakeholder relations within the corporation

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    Student Number : 8601897T - PhD Thesis - School of Law - Faculty of Commerce, Law and ManagementTraditionally, company law assumes that the directors’ role is to run the company for the benefit of its shareholders alone and to maximise profits for them. It can be argued, however, that this view is too narrow and outdated; that is, company directors should have regard to the rights and interests of a broader range of corporate stakeholders. Hence, the question is whether we should change our perception of the company or corporation from one run by directors dedicated exclusively to serving the interests of shareholders to that of a corporation whose main purpose is to bring benefit not only to its owners and creditors, but also to its employees, the community and the environment. Given that reforms of directors’ duties in light of the above considerations have found their way into legislation across the globe, this thesis examines how and to what extent legal rules and policies should develop in South Africa to place directors under a positive duty to take account of the interests of bodies other than shareholders. Current South African company law does not contain clear rules regarding corporate governance issues and the duties and liabilities of directors. These matters have been left to the common law and Codes of Corporate Practice. Thus, there is no extensive statutory scheme in South Africa, which covers the duties, obligations and accountability of directors. The focus in this thesis is on the rights and interests of employees and the premise that is defended is that it is valuable to corporations to provide employees with an institutionalised voice at board level. It is argued that there is global evidence that where employees participate in the decision-making processes of the company, performance is generally enhanced. This, in turn, directly impacts upon and improves economic productivity, generating a ‘win-win’ situation. The question of the duties of company directors and managers is attracting much attention in South Africa. With rapidly developing and changing labour legislation in South Africa, it is essential to consider the extent to which the country should reassess its traditional principles of company law and corporate governance policies in order to encourage participatory roles for employees in the workplace. It is argued that if South Africa is to improve corporate productivity levels with its re-entry into international markets, management and labour must find improved ways of dealing with one another. The main purpose of this thesis, therefore, is to propose and formulate a workable corporate governance model for South Africa – one that would be advantageous to all stakeholders, especially the employees. This is achieved by comparing and contrasting international models of corporate governance and by applying the best features of each to the unique South African corporate system of values, structures and traditions. It is suggested that the current unitary board structure operating in South Africa has become outdated and does not provide employees with rights enabling them to engage in the decision-making processes of the corporation with their employees at an adequate level. In its place, a two-tier board system of corporate governance is proposed. The economic success of a company will bring about social benefits to many stakeholder constituencies. This will not happen if the company is a financial failure. The issue of obliging directors to act primarily for the benefit of shareholders alone is questioned. Corporate governance reforms were undertaken in many parts of the world in the late 1980’s and early 1990’s. This reform process questioned whether the interests of the company should be managed for the shareholders alone or for the other corporate stakeholders as well. There are many views that strongly support the idea that corporate governance should be seen as a system by which corporations are to be governed for the benefits of all stakeholders, including shareholders, employees, creditors, suppliers and the community. In this way, companies should be run as communities in partnerships with all their stakeholders. Thus, this thesis proposes that the success of a company is inextricably intertwined with a consideration of the rights and interests of its employees and other stakeholders

    The impact of migration on adult mortality in rural South Africa: Do people migrate into rural areas to die?

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    Student Number : 0516841M - MSc research report - School of Public Health - Faculty of Health SciencesObjective This work investigates the hypothesis that individuals recently migrating into rural areas have a higher mortality than those always resident and that migrant deaths are more likely to be HIV/AIDS related than non migrant deaths. Methods Data from the Africa Centre Demographic Surveillance System (ACDIS), South Africa, was used for the analysis. A total of 41519 adults aged 18 to 60 years since their last visit dates were categorized into three groups; internal migrants, external in migrants and always resident individuals since 2001. Follow up period was from 1st January 2001 to 31st December 2005. Cox proportional hazard regression method was used to quantify the additional risk of dying for migrants who have recently migrated into the DSS area. Logistic regression was used to examine the relationship between migration status and dying from AIDS related complications for the members in the sample whose cause of death have been identified using verbal autopsy procedures. Results External in migrants into the DSS area were 1.52 times more likely to die than those always resident. After adjusting for the effects of sex, age group, socio-economic status and educational level an external in migrant has a relative risk of 1.19, [adjusted HR=1.19, P=0.001, 95% CI (1.08,1.32)] of dying compared to those always resident. Internal migrants were 18% less likely to die compared to always resident individuals, [adjusted HR=0.82, P=0.008, 95% CI (0.71, 0.95)] and males were 1.38 times more likely to die within the follow up period compared to females, [HR=1.38, P<0.001, 95% CI (1.28, 1.49)]. These results were statistically significant at 95% confidence level. Out of a total of 1119 deaths that occurred in 2001 and 2002 whose cause of death have been identified through verbal autopsy procedures, 763 (66%) died of AIDS. The odds of dying from AIDS are 2.09 if you are an external in migrant compared to an always resident member, [unadjusted OR = 2.09, P = 0.009 95% CI (1.38, 3.16)]. After controlling for other factors in the model, the odds of dying from AIDS as an external immigrant was 1.79 times, [adjusted OR = 1.79, P = 0.009, 95% CI (1.15, 2.77)] compared to those always resident. There was no significant difference in AIDS mortality between always resident individuals and internal migrants. The odds of a female dying of AIDS was 2.33 times, [OR = 2.33, P<0.001, 95% CI (1.78, 3.06)] compared to males after controlling for migration status, age, socioeconomic status and educational level. Conclusion External in migrants have an increased risk of death among adults aged 18 to 60 years compared to those always resident. External in migrants are also more at risk of dying from AIDS related illnesses than those always resident. Internal migrants are less likely to die than those always resident. Females are more at risk of dying from AIDS than males. In resource-poor settings, especially in many parts of Africa and other developing countries with very high prevalence of HIV/AIDS and over burdened health services in rural areas, it is important to identify and quantify some of these trends contributing to high disease burdens and mortality in rural areas in order to put in place effective interventions to better the health conditions of the people in these areas

    Using information and communications technology to improve the efficiency and accuracy of a utility's network data collection business process

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    Student Number : 0063608J - MSc(Eng) dissertation - School of Electrical and Information Engineering - Faculty of Engineering and the Built Environment“You can see the computer age everywhere except in the productivity statistics”. This offhand remark by Robert Solow, the Nobel prize-winning economist [1] has stimulated many other economists to conduct more rigorous analyses on the impact of information technology on productivity. The research presented in this dissertation has been conducted on a large telecommunications utility. An important business process of the utility, that of collecting information on its geographically dispersed network assets, was automated using mobile computing and wireless technologies. The research compared this newly developed automated process with the current, manual, process of sourcing the field network asset data using paper-based templates, and capturing the data manually from the templates. The results of the pilot for this automated business process were encouraging and demonstrated an improvement of over 50% in the productivity of the data collection process, and its integrity. An important aspect of the research outlined in this dissertation was to design and implement the mobile computer-based electronic data collection prototype to minimise user obstruction to the technology deployed. The prototype was tested for technology acceptance by the targeted field workers. This test also proved successful. The research demonstrated that an improvement in productivity of over 50% was achievable from a well-considered investment in information technology. The results from the research also pointed the way for the deployment of this data collection solution in other utilities, e.g. electricity distribution, water reticulation, and municipalities. Through user prototype tests and a cultural intervention process on the targeted users (field workers), the research also demonstrated how the automated business process can be geared for use by low-skilled field workers, so important to improve productivity in developing economies such as those in Africa

    Design and construction criteria for domes in low-cost housing

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    Student Number : 0003370N - MSc dissertation - School of Civil and Environmental Engineering - Faculty of EngineeringThis dissertation investigates the different design and construction considerations involved when building a masonry dome. A detailed shape investigation was undertaken in order to summarize the best shaped dome structures. General recommendations are given for the shapes that produce the least tension and the most useable space. The effects of openings, temperature loading and wind loading were considered and a finite element analysis of the final structure was undertaken. It was found that regions of high tension exist around openings, especially under temperature loading, and materials suitable to resisting this tension were investigated (fibre plaster, chicken wire mesh and wire wrapping around openings). The final structure was built using an inflatable formwork. The construction procedure was well documented and a study of alternative methods of construction is presented. This dissertation shows that a durable, architecturally and structurally efficient low-cost masonry dome can be built if proper attention is given to minimizing and resisting tension within the structure
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