The electrochemical hydroxylation of aromatic substrates
- Authors: Rautenbach, Daniel
- Date: 2002
- Subjects: Aromatic compounds , Hydroxylation
- Language: English
- Type: Thesis , Masters , MTech (Chemistry)
- Identifier: vital:10959 , http://hdl.handle.net/10948/94 , Aromatic compounds , Hydroxylation
- Description: The electrochemical hydroxylation of aromatic substrates was investigated in some detail, with the view to develop a method, which could produce dihydroxybenzenes in acceptable yields. Of particular interest was the selectivity and yield of the 1,4-dihydroxybenzenes. Two distinctly different methods were investigated in order to achieve this goal, acyloxylation and direct electrochemical hydroxylation. Acyloxylation is the process where radical cations generated at the anode undergoes nucleophilic attack by acetate anions. The resulting aromatic acetates so produced can then be hydrolysed to the phenolic compounds. Two nucleophile systems were considered in the investigation, acetates (acetoxylation) and trifluoro-acetates (trifluoro-acetoxylation). These investigations were conducted under a variety of conditions using phenol and phenyl acetate as starting materials. From the results it was, however, concluded that the acetoxylation of these aromatic compounds occurs in unacceptable product and current yields. Trifluoro-acetoxylation on the other hand showed promise, but due to the nature and cost of the reagents it was deemed to be an impractical process. Direct electrochemical hydroxylation: in which the radical cations produced at the anode undergoes nucleophilic attack by water producing the corresponding dihydroxybenzenes. These dihydroxybenzenes are then further oxidised to the benzoquinones, which then undergo reduction at the cathode in order to produce the corresponding dihydroxybenzene. In this process phenol, 2-tert-butylphenol and 2,6-di-tert-butylphenol were investigated as substrates. The results indicated that the yield towards the 1,4-dihdroxybenzenes increased as the degree of substitution on the ring increased.
- Full Text:
- Date Issued: 2002
The establishment of an effective farming system for the Allan Waters communal area in the Eastern Cape Province
- Authors: King, Bryan Rhodes
- Date: 2002
- Subjects: Agricultural systems -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MTech (Agriculture)
- Identifier: vital:10821 , http://hdl.handle.net/10948/95 , Agricultural systems -- South Africa -- Eastern Cape
- Description: Allan Waters, a communal area near Queenstown in the former Ciskei of the Eastern Cape Province of South Africa, have about 80 households who are involved in agriculture. These households were surveyed with two questionnaires. The first was at household level, focusing on the current socioeconomic situations and farming systems. Data were collected from sixty-three households in the village. The socio-economics questionnaire was divided into sections: demographic information, land and agricultural information, income and expenditure. In order to improve the livelihood of the households and to secure food production and food security, a situation analysis of the rural farmers was carried out using typology as a research tool. Typologies were built in order to analyze the diversity of production units (farms) or households (agricultural households). To define household typologies, factors such as land, source of income, modes of farming and composition of the family were used to identify six typology categories and to divide these into two main groups. The two main groups comprised of (a) livestock farming and (b) non-livestock farming or very little farming activities. The six types are as follows: Type 1: Poverty-stricken households Type 2: Newly arrived households Type 3: Households’ depending on old age pensions Type 4: Households’ main income from old age pensions and supported by substantial farming Type 5: Households’ revenue generated from business, wages and farming Type 6: Full time farming Five types had access to grazing and arable land for agricultural purposes, but type two had not yet been granted the rights to graze or the use of arable fields for agricultural purposes by the village. The source of income for the households in type one was made up of welfare grants and remittances. Types three and four, mainly depended on pensions when compared to the other four types. The households in type five mainly received incomes from farming and business. In type six, the main income received was from farming. The most common modes of farming for the types were: garden-poultry- dry land- crop- cattle-sheep-goats. Using the data from the first questionnaire, the three active agricultural types were targeted with a production survey (28 households). The production survey revolved around animal production, but a number of questions had to do with general information concerning agriculture. From the survey, the households reported that the main aim for keeping livestock and chickens was self- consumption and sale of animals, except in the case of sheep, which were kept for wool production. In the case of the wool farmers, the committee controlled activities such as mating of animals, grazing management, shearing, dipping of animals and wool sorting. The other tasks were left to the farmer himself. Wool data obtained for 2001 indicated that the average fleece weight was 3.88 kg greasy wool per sheep, with an A- to C- length. The fibre diametre of the wool in general fell in a medium class (21.1 micron). From the survey a number of projects were identified to assist the rural farmers in improving the livelihood of the households and in securing food production and food security.
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- Date Issued: 2002
The evaluation of waste minimization/waste treatment strategies for a commercial production process of 4-methyl-3-thiosemicarbazide
- Authors: Bennen, Wilroy
- Date: 2002
- Subjects: Hazardous wastes , Hazardous substances -- Analysis
- Language: English
- Type: Thesis , Masters , MTech (Chemistry)
- Identifier: vital:10951 , http://hdl.handle.net/10948/97 , Hazardous wastes , Hazardous substances -- Analysis
- Description: Chemical synthesis is closely related to waste minimization. There is no chemical process that does not produce waste. The methods used by industry to deal with this waste is a major environmental concern. This thesis describes the laboratory scale waste minimization and waste treatment strategies for the commercial production process of 4-methyl-3-thiosemicarbazide (MTSC). The production process of 4-methyl-3-thiosemicarbazide was investigated with the aim of increasing the isolated yield of MTSC and at the same time decrease the amount and toxicity of effluent obtained. During this study, parameters were investigated such as the use of excess DIPEA and the temperature of the reaction. Preliminary studies clearly showed that both factors have a significant influence on the final yield of the product. The next part of the investigation was to optimize the two parameters influencing the isolated yield of the MTSC. For this investigation, a multi factorial design was used to determine the optimum conditions in the MTSC yield response. From the results obtained, it was clear that the excess of DIPEA and the temperature of the reaction both need to be high to obtain high yields. These theoretical results were confirmed by results obtained practically, where yields of up 82 % were obtained, but it became clear that even higher yields could be obtained since chromatographic results showed yeilds as high as 90 %. The mass balance of the MTSC synthesis showed a loss of approximately 30 grams per reaction. This loss may have an influence on the final yield. The effluent obtained during the synthesis of MTSC was investigated and a waste treatment protocol was established to reduce the high COD value of the MTSC effluent. The protocol consists of two steps used for the clean up of the effluent. The first being a cooling step; the effluent was cooled at 0oC to induce precipitation of a solid, consisting mostly of MTSC. The second step is a high pressure wet oxidation of the effluent with oxygen in a high pressure reactor. The remaining compounds in the effluent were oxidized, resulting in another precipitate, consisting mostly of sulphur. After the oxidation the COD value of the effluent was decreased by 98 % to a value of 0.4 %. The MTSC present in the precipitate obtained after cooling could be isolated and purified, to add to the yield of the synthesis. The sulphur obtained during the oxidation could also be isolated and reused, or sold to prevent it from contaminating the environment.
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- Date Issued: 2002
The evolution of a security community through a process of integration: problems and prospects for the SADC region
- Authors: Šebek, Vita
- Date: 2002
- Subjects: Political stability -- Africa, Southern , Southern African Development Community , National security -- Africa, Southern , Africa, Southern -- Economic integration
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2831 , http://hdl.handle.net/10962/d1003041
- Description: This thesis examines the security problematic of African states and focuses more particularly on the SADC region. It links the security problematic with the transactionalist approach to (supra)national integration and the concept of a security community, introduced into internatIonal relations theory by Karl Deutsch and his colleagues. In relation to the (in)security of SADC member states, the thesis attempts to demonstrate that national integration of these states (i.e. the establishment of an amalgamated security community) has at least to accompany if not precede the establishment of a security community at the regional level (i.e. a pluralistic security community). Since threats to the security of SADC member states are mainly nonmilitary in nature, the 'realist' concept of security is broadened to include political, economic, societal and environmental aspects of security at different levels. Furthermore, Deutsch's concept of a security community is redefined in line with the 'new security thinking' and adapted to the situation in African states. Moreover, this thesis attempts to demonstrate that it is essential for SADC member states to become strong and socio-economically cohesive in order to improve their competitiveness in relation to developed states, especially in their ability to deal with internal and ransnational/regional threats to their security, which are (in)directly caused and perpetuated by the lack of national integration, inefficient state-making and underdevelopment - the sources of their weakness.
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- Date Issued: 2002
The evolution of online news: a comparative case study of the process of implementation at two South African news organisations
- Authors: Knight, Margaret Anne
- Date: 2002
- Subjects: Electronic newspapers -- South Africa , Electronic newspapers -- United States , Electronic news gathering -- South Africa , Electronic news gathering -- United States
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3447 , http://hdl.handle.net/10962/d1002901 , Electronic newspapers -- South Africa , Electronic newspapers -- United States , Electronic news gathering -- South Africa , Electronic news gathering -- United States
- Description: This study examines the evolution of online news strategy in South African and American newspaper companies, and compares the approaches used in the two countries. The Internet has had a major effect on news worldwide, and has contributed to sweeping changes in the news industry in all media. This study looks at the changes and the evolving strategy wrought by online news in the newspaper industry in two countries. In order to do this comparison, a model of the US experience has been constructed, using material published in the US academic and professional journalism press. Since there is no equivalent published material available dealing with the South African experience, interviews were conducted with staff at two newspaper companies (Johnnic and Naspers), and a broad historical overview was created for each company. These “narrative histories” were then compared with the US model, and areas of commonality and difference were highlighted and discussed. Several structural and national differences be tween the two countries were also raised and analysed. Finally, a conclusion as to how applicable the US model is to the South African experience is drawn, and suggestions are made for further study.
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- Date Issued: 2002
The identification of factors that contribute to the competitive advantage of the catalytic converter industry cluster in the Eastern Cape
- Authors: Manlee, Tamaryn
- Date: 2002
- Subjects: Competition , Industrial management , Automobiles -- Catalytic converters
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10892 , http://hdl.handle.net/10948/99 , Competition , Industrial management , Automobiles -- Catalytic converters
- Description: The research problem addressed in this study was to determine what the main factors are that contribute to the competitive advantage of the catalytic converter industry cluster in the Eastern Cape. To achieve this objective theoretical models of competitive advantage and literature of industry clustering were identified. For the models on competitive advantage, Porter’s diamond was used for national competitive advantage and Porter’s model on the competitive environment, which affects the competitive advantage of a region. Other theories on competitive advantage of cities and regions were identified, leading up to the theory on the cluster approach. The literature mentioned was broken down and analysed using literature, from knowledgeable people in the automotive industry in the Eastern Cape, identified during the study. A questionnaire was developed to test the degree to which the catalytic converter industry cluster in the Eastern Cape is in agreement with the literature study. The empirical study obtained a strong concurrence with the literature study on national competitive advantage and the theory of clusters. This resulted in a strategy for the catalytic converter industry cluster to sustain competitive advantage and remain globally competitive.
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- Date Issued: 2002
The immobilization of Microcystis aeruginosa PCC7806 on a membrane nutrient-gradostat bioreacator for the production of the secondary metobolites
- Authors: Strong, Peter James
- Date: 2002
- Subjects: Microcystis aeruginosa , Myrocystins , Bioreactors
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11083 , http://hdl.handle.net/10948/283 , Microcystis aeruginosa , Myrocystins , Bioreactors
- Description: A module and an inoculation technique were developed that would allow for the efficient immobilization of Microcystis aeruginosa PCC7806 on a synthetic membrane. A variety of module types, membranes (ceramic, tubular polyethersulfone and externally skinless polyethersulfone capillary membrane), and methods of immobilization (adsorption, pressure filtration and a developed technique that involved drying a cell slurry on a membrane) were assessed. The morphological properties that affected the immobilization of Microcystis aeruginosa PCC7806, as well as the effects of immobilization upon cell morphology were assessed. Cells in the stationary growth phase, which had a well-developed extra-cellular polysaccharide layer and no gas vesicles, were optimal for immobilization. Microcystin production under immobilized conditions was assessed under different nitrate concentrations, light intensities, biofilm thickness and immobilization times. Additional work included assaying for Microcystin production of two airlift-grown cultures under a high light intensity and complete nutrient deprivation and the inoculation of a ceramic membrane. An immunological technique was used to elucidate where toxin production was greatest within a biofilm immobilized upon an externally skinless polyethersulfone capillary membrane. The externally skinless polyethersulfone capillary membrane was evaluated to assess homogeneity and the physical differences between membrane batches that led to the erratic, incomplete biofilm formation, as a biofilm of a constant thickness could not be immobilized. Microcystis aeruginosa PCC7806 was exposed to a variety of solvents in order to permeabilize the cyanobacteria, as that would have enabled a truly continuous extraction process for the metabolite. FDA hydrolysis had to be optimized in order to use it as an indicator of cell viability. In addition a single-step extraction of Microcystin was attempted using live bacteria. A capillary membrane module, containing the externally skinless polyethersulfone capillary membrane, inoculated using pressure filtration, was the most efficient combination to establish a biofilm. Cells that were no longer actively dividing and that lacked buoyancy displayed superior immobilization to cells that were actively dividing and buoyant. The immobilized cells did produce Microcystin but in much lower concentrations to cells grown in an airlift culture. Biofilms grown with a higher nitrate concentration, a lower biofilm thickness and a lower light intensity had a higher specific microcystin content, while biofilms with a higher nitrate concentration a lower light intensity and a longer growth period displayed the a greater toxin production per mm2 of membrane. Microcystin occurred at its highest concentration in cells just above the pore opening. The diffusion of nutrients occurred relatively quickly to the outside layers of the biofilm, with a true gradient being established laterally from these nutrient veins that were above the pores. Permeabilization of the cells proved unsuccessful, as cells that remained viable did not release the intracellular compound into the surrounding medium.
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- Date Issued: 2002
The impact of media commercialisation on programming: a study of Radio Uganda
- Authors: Lwanga, Margaret Jjuuko Nassuna
- Date: 2002
- Subjects: Radio programs -- Uganda , Radio Uganda , Public radio -- Uganda
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3453 , http://hdl.handle.net/10962/d1002907 , Radio programs -- Uganda , Radio Uganda , Public radio -- Uganda
- Description: The 1980s and 1990s saw two major changes in the political economy of the media and the world economy at large: technological advancement and transfer and privatisation. There were significant shifts in media industries: newspapers, broadcasting, cinema and telecommunications when governments begun re-regulating their air waves so as to permit private satellite transmission via both encryption and free-to-air, in addition to public service and private channels. In most societies where these changes have taken place, public service broadcasting has been threatened by the rapid rise of commercial institutions, resulting in stiff competition for audiences. This study set out to determine the extent to which commercialisation, in the era of liberalisation and commercialisation of media services in Uganda, has affected Radio Uganda’s programming. Using a combination of qualitative and quantitative methods of investigation, I have established that while Radio Uganda still maintains certain public service principles and values, programming policy has increasingly been changed by commercial considerations. This is shown by the recent rise of commercial programmes and a fall in education and developmental programmes. Limitations of finance and other resources have compromised the roles and character of public service radio programming. The majority of programmes currently on Radio Uganda are evidently geared to attract advertisers rather than serve the public interest. The study recommends, among other measures, that the licence fee be developed as a source of revenue for Radio Uganda. Secondly, government should inject more funding into public service broadcasting institutions to supplement other sources of income, before granting them autonomy. Thirdly, while advertising and sponsorship brings in a considerable amount of revenue, it should not take a central place that undermines the listener’s interest in radio programming. The Broadcasting Council should therefore map out solid policies that will systematically guide Radio Uganda in its programming in the new order.
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- Date Issued: 2002
The impact of multi-skilling training on the paintshop production environment and its employees at Volkswagen South Africa (VWSA)
- Authors: Bhika, Chandrika
- Date: 2002
- Subjects: Employees -- Training of , Automobile industry and trade -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10852 , http://hdl.handle.net/10948/130 , Employees -- Training of , Automobile industry and trade -- South Africa -- Eastern Cape
- Description: Global competition and rapid technological change have been the driving forces for a more flexible and competent workforce. Continuous employee training assists organisations to achieve their goals by adding value to their key resources, the human factor. The demand for a more qualified workforce becomes a strategic force in the effort to raise competitiveness. Providing, obtaining and improving the necessary skills are important in responding to a rapidly changing international economy. Life-long learning and continuous skills development are the new requirements imposed by our knowledgeintensive society. The overall purpose of the research was to determine the impact of multi-skilling training (MST) on the paintshop production environment and its employees at Volkswagen South Africa (VWSA). The objectives of this research were to: Identify the elements of multi-skilling training and guidelines for its development and implementation; Critically evaluate the current system; Determine the impact of multi-skilling training on the production environment in the paint shop at VWSA The research methodology for this study comprised the following steps: Firstly, the development and implementation of MST at Volkswagen South Africa was assessed. The elements of MST and its impact on production and the employee worldwide were determined through the literature study. Secondly, the limitations of the current MST system used in the paintshop at Volkswagen South Africa were assessed in an empirical study, which involved completing of questionnaires. The empirical study proved that the current MST system employed in the paintshop at Volkswagen South Africa had assisted in improving production, and increasing the employees’ morale. The final step of this study entailed the formulation of recommendations, which are as follows: · Sufficient time should be allocated for practical training. · Frequent job rotation must be implement ed. · Advanced MST must be implemented after completion of Level Four. · MST should be presented in English, Afrikaans and Xhosa.
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- Date Issued: 2002
The implementation of environmental education policy in Namibia: perceptions of a range of decision-makers
- Authors: Katoma, Loini-Nyanyukweni
- Date: 2002
- Subjects: Environmental education -- Namibia , Education and state -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1563 , http://hdl.handle.net/10962/d1003445 , Environmental education -- Namibia , Education and state -- Namibia
- Description: This study is the first cycle of an action research project that focuses on the implementation of the Environmental Education Policy in Namibia. Perceptions of Namibian decision-makers were sought with regard to their understanding of the concepts ‘environment’ and ‘environmental education’, as well as to identify environmental problems and obstacles to the implementation of the Environmental Education Policy. The approach of coming up with options to address the identified problems/obstacles/constraints, was employed in this study. To this effect, interviews, a workshop, observations and reflections on the process of implementation resulted in a wealth of data. The findings shed light on possible solutions to address the identified problems and obstacles. The results revealed that community participation, skills development and the proper co-ordination of environmental education activities are imperative in addressing the obvious policy-practice gap. Decision-makers uncovered the fact that the socio-economic situation of our people necessitated pulling our resources together and working as a team. The overall perceptions are that the environment is everyone’s business and that we should zealously use it and carefully guard it, not only for ourselves but also, for the benefit of coming generations.
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- Date Issued: 2002
The independent high rate algal pond as a unit operation in tertiary wastewater treatment
- Authors: Clark, Stewart James
- Date: 2002
- Subjects: Algae -- Biotechnology , Sewage -- Purification -- Biological treatment
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4092 , http://hdl.handle.net/10962/d1007805
- Description: The development of the High Rate Algal Pond (HRAP) as an independent tertiary treatment unit operation for phosphate and nitrate removal is reported. A novel Integrated Algal Ponding System (lAPS) design is proposed for nutrient removal from the effluents of both a conventional domestic sewage treatment plant and from an Advanced Integrated Wastewater Ponding System (AIWPS). The viability of an independently operated HRAP has been identified and termed the Independent High Rate Algal Pond (l-HRAP). A 500 m² pilot 1- HRAP was operated in such a way as to facilitate the precipitation of calcium phosphate, known to be controlled by pH (greater than 9.4) and resulting in final phosphate levels of less than 1 mg.L⁻¹ as P0₄-P. The incorporation of the I-HRAP into a denitrification process was also investigated. Continuously fed column reactors, utilising algal biomass as a carbon source, showed that the heterotrophic bacterial community dominant in the anaerobic algal sludge were denitrifying the nitrate in the feed. It was demonstrated that as the cultures were stressed (using increased nitrate concentrations, anaerobiosis and light starvation) total polysaccharide (TPS) concentrations increased, with a notable increase 111 the exopolysaccharide (EPS) fraction. These experiments corroborated the hypothesis that harvested microalgal biomass can be manipulated to produce, and release, exopolymeric substances under stress conditions, and which may serve as carbon source for denitrification. In both batch flask studies and in laboratory-scale reactor systems, harvested microalgal biomass from an HRAP was shown to produce exopolymeric substances under stress conditions. Initial high loading-rates of greater than 20 mg.L⁻¹ NO₃-N resulted in double the amount of exopolysaccharide production than in flasks with initial low loading-rates (less than 5 mg.L⁻¹ NO₃-N). Making use of an upflow anaerobic sludge blanket-type degrading-bed reactor, and an anaerobic, flooded trickle filter (ANTRIC) receiving HRAP effluent, the relationship between denitrification and the changes in polysaccharide content was investigated. This phenomenon has considerable beneficial implications in biological wastewater treatment systems where high nitrate concentration in the final effluent is a potential mitigating factor. Identification of the heterotrophic bacteria active in the denitrification process was attempted. This study presents a first report on the development and operation of the I-HRAP and has been followed by a technical-scale pilot plant evaluation of the process in the tertiary treatment of domestic wastewaters.
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- Date Issued: 2002
The influence of structure, density and direct use benefits on the harvesting of trees in the rural village of Pikoi, Eastern Cape, South Africa
- Authors: Motinyane, Teboho R
- Date: 2002
- Subjects: Deforestation -- Control -- South Africa -- Eastern Cape , Deforestation -- South Africa -- Eastern Cape , Fuelwood consumption -- South Africa -- Eastern Cape , Trees -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4771 , http://hdl.handle.net/10962/d1007705 , Deforestation -- Control -- South Africa -- Eastern Cape , Deforestation -- South Africa -- Eastern Cape , Fuelwood consumption -- South Africa -- Eastern Cape , Trees -- South Africa -- Eastern Cape
- Description: The people of Pikoli in the Peddie district of the Eastern Cape are mostly unemployed and earn most of their income from old-age allowances. The place is remote and 'modern' amenities such as paraffin and petroleum gas are expensive. Electricity and transport are unavailable. There is heavy reliance on woody plants for fuel and for materials for construction and fencing and to some extent medicinal and ritual uses. Indigenous trees in this rural area are threatened by over-utilisation and the absence of clear government management policies. The over-utilisation of these resources is leading to deforestation. It was proposed at the beginning of this study that people who harvest trees cause similar results to the piosphere effect caused by the herbivores on the rangeland. Ecological-economic analysis was performed to find a common ground between the people's income and needs so that effective sustainable management strategies can be developed. A combination of semi-structured interviews, direct observations and ecological surveys were used to gather information about: Tree species used, and for what purpose in Pikoli; Individual tree species preference by inhabitants; Change in tree density in response to changes in utilisation intensity at varying distances away from the village; The local direct use benefits inhabitants derive from utilising indigenous tree resources. The study showed that the people of Pikoli use a variety of 23 indigenous trees and that they have marked preferences regarding the tree species they use for fuelwood and construction purposes. Although Ptaeroxylon obliquum is a highly preferred species for fuelwood and construction, its popularity can also be linked to its high relative abundance in this area. Other species such Maytenus undata and Pappea capensis are also highly preferred although they are harvested at much greater distances from thecentre of the village. Change in individual tree density in response to changes in utilisation intensity at varying distances away from the village showed clearly that a piosphere effect also applies to human harvesting. The average number of individual trees closer (1 200 m) to the village centre was 2 trees per 100 m², and their numbers increase to approximately 35 trees per 100 m² at a distance of about 3 000 m from the village centre. The study reports on the direct use benefits derived by the people of Pikoli from harvesting tree resources. The average total net value of trees harvested for fuelwood was R4089.09 (US$ 359.01) per household per annum. The value of tree resources harvested represents a large percentage of average households' annual income. Therefore, the economic benefits households derive from utilising tree resources are high. Indigenous tree resource use in this rural village seems to be unsustainable and the inhabitants seem to be aware of it. However, they have few alternatives. Their economic conditions do not allow them to afford alternative resources available in the formal market.
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- Date Issued: 2002
The investigation of the hydrolysis reaction of m-phenylene to resorcinol
- Authors: Khaile, Thebeeapelo John
- Date: 2002
- Subjects: Resorcinol
- Language: English
- Type: Thesis , Masters , MTech (Chemistry)
- Identifier: vital:10961 , http://hdl.handle.net/10948/107 , Resorcinol
- Description: The purpose of this study was to characterise the resinous material formed during the acid catalysed hydrolysis of m-phenylenediamine (MPDA) to resorcinol, and to establish a reaction mechanism that could explain the formation of both resorcinol and the resinous materials in the reaction. A further objective was to determine reaction conditions that would lead to reduced formation of the resins during the hydrolysis reaction. The number of compounds present in a sample taken during the course of the hydrolysis reaction was determined by HPLC fitted with a photodiode array detector. Five main components were detected. These compounds were identified as mphenylenediamine, m-aminophenol, resorcinol, 3,3’-aminodiphenylamine and 3- amino-3’-hydroxydiphenylamine by means of GC-MS. 3,3’-Diaminodiphenylamine is formed by self-condensation of MPDA and 3-amino-3’-hydroxydiphenylamine is formed by the reaction of MPDA with resorcinol. The degree of formation of these intermediates is substantially reduced when MPDA is added dose-wise to phosphoric acid at a reaction temperature of 220oC. The reaction mechanism of the hydrolysis reaction was investigated by isotopic lable incorporation, followed by analysis by NMR. This was done by hydrolysing MPDA using deuterated phosphoric acid (D3PO4). D3PO4 was generated by dissolving phosphorus pentoxide in deuterium oxide. The resorcinol product obtained from the hydrolysis using D3PO4 was found to be deuterated on the C-2, C-4 and C-6 positions. This suggests that the hydrolysis reaction involves protonation of MPDA on these positions, and this results in the formation of an iminium ion as one of the resonance forms. Hydrolysis then occurs on the positively charged carbon of this species. Fertiliser grade phosphoric acid can be used in the hydrolysis reaction, provided sulphates are removed before the acid is used in the hydrolysis reaction. The hydrolysis reaction using either ammonium sulphate or sulphuric acid produces resorcinol in yields lower than 60% if the hydrolysis is conducted in one pass. If these catalysts are used in the hydrolysis reaction, the reaction mixture needs to be re-heated after removal of resorcinol in order to increase the yield. Hydrolysis of MPDA using zirconium phosphate as catalyst gave resorcinol yields in excess of 90% over 24 hours. These reactions were carried out at very low concentrations of MPDA (0.3%). The mode of catalysis in these reactions is unclear. There is a possibility that the reaction is catalysed by phosphoric acid that leaches out of zirconium phosphate at high temperatures. The reaction might therefore not differ mechanistically from the phosphoric acid catalysed reaction. Further studies are required to clarify this point.
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- Date Issued: 2002
The legal effect of a coup d'etat on traditional constitutional concepts
- Authors: Mkwentla, Nelson Koala
- Date: 2002
- Subjects: Coups d'état , Constitutional law
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:3684 , http://hdl.handle.net/10962/d1003199 , Coups d'état , Constitutional law
- Description: This thesis deals with constitutional law and other legal subjects such as Jurisprudence and Judicial Review. One constitution is distinguishable from another by its own provisions. These provisions are usually referred to as either the basic characteristics or features of the particular constitution and these are invariably derived from the basic political philosophy and constitutional arrangements of the particular country. A coup affects these characteristics in different ways. Some automatically disappear as being incompatible with the revolution; some are modified, others are strengthened. The usurpers may choose to set aside the constitution completely and replace it with another, or amend it to suit the new situation, or rule without any constitution. This often happens amidst the rattle of weapons and the whirr of military engines in and around the capital of a given country on that awesome occasion. This thesis sets out to examine the legal aspects of a coup d’ etat. The thesis is divided into six broad sections. Part one will deal with the theoretical background. I shall discuss an overview of Kelsen’s pure theory of law. The second part deals with the scope of its application in revolutionary situations and will also touch upon the reason behind the Kelsen’s theory as shown by decided cases from country to country. The third part deals with the essence as well as the significance of the doctrine of necessity to validate unconstitutional acts in the case of a coup d’ etat. This discussion is to pave the way for the fourth part which is to explore the position of judges who took oath of office under the old constitution. I am to explain their position after a coup d’ etat. The fifth part forms the gist of my research. I shall examine the effect of a coup d’ etat on traditional constitutional concepts such as fundamental rights, separation of powers, rule of law and judicial review in the military regime. The sixth part will deal with African experience. I shall include recommendations and conclusions drawn from the Lesotho and Uganda experiences.
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- Date Issued: 2002
The molecular microbial ecology of sulfate reduction in the Rhodes BioSURE process
- Authors: Chauke, Chesa Gift
- Date: 2002
- Subjects: Water -- Purification -- Biological treatment , Acid mine drainage , Water -- Microbiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4082 , http://hdl.handle.net/10962/d1007475 , Water -- Purification -- Biological treatment , Acid mine drainage , Water -- Microbiology
- Description: The research reported here investigated the use of a Baffle Reactor in order to study aspects of the biological sulfur cycle, where a floating sulfur biofilm formation occurs and where complex organic compounds provide electron donor sources. The development of a laboratory-scale Baffle Reactor model system satisfied the requirements for sulfate reducing bacterial biomass growth and sulfur biofilm formation. Since relatively little is known about the microbial ecology of floating sulfur biofilm systems, this study was undertaken to describe the sulfate reducing sludge population of the system together with its performance. A combination of culture- and molecular-based techniques were applied in this study in order to investigate the microbial ecology of the sulfate-reducing bacteria component of the system. These techniques enabled the identification and the analysis of the distribution of different sulfate reducing bacterial strains found within the sludge bioreactors. Strains isolated from the sludge were characterised based on culture appearance, gram staining and scanning electron microscopy morphology. Molecular methods based on the PCR-amplified 16S rRNA including denaturing gradient gel electrophoresis were employed in order to characterise sulfate-reducing bacteria within the reactors. Three novel Gram negative sulfate-reducing bacteria strains were isolated from the sludge population. Strains isolated were tentatively named Desulfomonas rhodensis, Desulfomonas makanaiensis, and Clostridium sulforhodensis. Results obtained from the Baffle Reactor showed that three dominant species were isolated from the DNA extracted from the whole bacterial population by peR. Three of these were similar to those mentioned above. The presence of these three novel unidentified species suggest that there are a range of other novel organisms involved in sulfate reduction processes.
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- Date Issued: 2002
The pursuit of paternal custody
- Authors: Pieterse, Johanna Tyziena
- Date: 2002
- Subjects: Custody of children -- South Africa , Paternal custody -- South Africa , Divorced fathers -- South Africa , Father and child -- South Africa
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3398 , http://hdl.handle.net/10962/d1018266
- Description: Issues concerning children may be the most intense and emotive areas of divorce and can lead to spectacular legal battles. Social work practice revealed that it is often the father who leaves the court, stripped of his fatherhood by a court order that only grants him limited access to his own children. Some divorced fathers disengage from their children's lives but there is documented evidence of South African fathers who desire continuity in their relationships with their children after divorce. An interest in these fathers prompted this study. Fathers who challenged maternal custody were selected since it was assumed that their lived experiences would include non-custodial as well as custodial fatherhood. The study was approached from a constructivist position and was further informed by a family systems theory. South African and international literature was perused followed by an exploratory study on the relatively uncharted terrain of paternal custody. A qualitative method was used and one unstructured interview with a schedule was conducted with each of the five respondents who were selected according to non-probability purposive sampling methods. Interviews were recorded and transcribed verbatim. Data was analysed cross-sectionally around certain themes and categories that were extracted from the data. The most significant findings of the study which appear to resemble some earlier national and international findings, are summarised as follows: Some fathers appear to have sound motives for pursuing custody of their children. These fathers, if afforded the opportunity, find fulfilment in parenting their children whom they perceive to be happy and prosperous in their care. There are fathers in whom divorce causes clear and profound signs of distress which appear to be related to the loss of the pre-divorce father I child relationship. The feeling of powerlessness to effect the well-being of their children as they see it was emphasised. Recommendations generated from these findings relate to the elimination of gender bias from custody decisions, including fathers in therapeutic interventions with divorced families and the provision of family courts and mediation services as suggested in the White Paper for Social Welfare. Recommendations for future research are also presented.
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- Date Issued: 2002
The relationship between the leadership, internal quality, and customer satisfaction levels of dealerships in a South African motor vehicle organisation
- Authors: Botha, Jennifer
- Date: 2002
- Subjects: Consumer satisfaction , Automobile dealers -- South Africa , Industrial productivity , Customer services
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1185 , http://hdl.handle.net/10962/d1002802 , Consumer satisfaction , Automobile dealers -- South Africa , Industrial productivity , Customer services
- Description: This research investigates the relationship between the leadership, internal quality, and customer satisfaction levels in the dealerships of a South African motor vehicle organisation. The Service Profit Chain provides the background theory to this relationship, by suggesting that various factors within the service delivery system of an organisation affect the level of customer satisfaction. From the Service Profit Chain, it is established that two of the prevalent factors affecting customer satisfaction, are leadership and internal quality. The Full Range Leadership Development Theory provides the backdrop for analysing the leadership style of each dealership by using the Multifactor Leadership Questionnaire. The Competence Process forms the theoretical construct against which the internal quality of these dealerships is assessed using the Organisation Competence Analysis Questionnaire. Information was gathered, using these two instruments, from a sample of 85 motor vehicle dealerships within South Africa. The customer satisfaction levels at each of these dealerships, is measured by the motor vehicle organisation’s own instrument, known as the Customer Satisfaction Index. Data obtained from each instrument, for the respective dealerships, was then statistically analysed. However, due to the low reliability of the instruments used in this research, the results of this study indicate that there is no relationship between the leadership, internal quality, and customer satisfaction levels within a South African motor vehicle organisation. Therefore we can conclude that the null hypotheses can not be rejected.
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- Date Issued: 2002
The relationship between three anxiety related clusters in projective drawings and anxiety and ego-strength scales of the Minnesota multiphasic personality inventory-2
- Authors: Brink, André
- Date: 2002
- Subjects: Projective techniques , Personality assessment , Personality tests , Anxiety , Minnesota Multiphasic Personality Inventory
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2942 , http://hdl.handle.net/10962/d1002451 , Projective techniques , Personality assessment , Personality tests , Anxiety , Minnesota Multiphasic Personality Inventory
- Description: Based on the shortcomings of past research, the need for understanding and investigation of the general relationship between self-report measures and human figure drawings required understanding and investigation (Riethmiller & Handler, 1997b; Waehler, 1997) while utilising a quantitative, configural scoring approach. Riethmiller and Handler (1997a; 1997b) hypothesised that subjects have one of two typical approach styles to anxiety/stress that influences their execution of the Human Figure Drawing (HFD) Test: “Avoidance” or “Coping” as measured by composite scoring index clusters. They argue that these two approach styles had to be taken into account when investigating anxiety on the HFD Test. According to Handler and Reyher (1965) those who experience more intense anxiety typically rely on an “Avoidant” approach, while those with lower anxiety typically rely on a “Coping” approach. The “Coping” response is hypothesised to suggest good ego-strength, and the “Avoidant” response poor ego-strength. Handler and Reyher (1964; 1965; 1966) also argued that there are two sources of anxiety on projective drawings: internal and external sources of anxiety. They hypothesised that the “External” anxiety cluster (measured by utilising the car drawing) and self-report measures both assess ‘external’ anxiety. Using Handler’s (1967) HFD index scoring manual, this research therefore inve stigated the level of correlation of the two MMPI-2 anxiety scale scores with (a) the hypothesised Stress Approach HFD cluster scores, as well as with (b) the “External” anxiety cluster score, while the hypothesised Stress Approach HFD cluster scores were compared with the (c) MMPI-2 ego strength scale score. The results of the investigated relationships yielded non-significant correlations overall. The differences in nature of the two measurement instruments, and the potential weaknesses of this study, as two likely explanations for these correlations, are discussed. In the consideration of the differences of the two measurement instruments, the weaknesses of SR measures and criterion-related validity are discussed while self- attributed and implicit motives are contrasted with each other. Potential extraneous variables and possible truncated range are discussed as potential weaknesses of this study.
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- Date Issued: 2002
The remote configuration of devices within home entertainment networks
- Authors: Dembovsky, Colin
- Date: 2002
- Subjects: Home entertainment systems , Home video systems
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4685 , http://hdl.handle.net/10962/d1007795 , Home entertainment systems , Home video systems
- Description: This thesis examines home entertainment network remote configuration solutions. It does so by inspecting four home entertainment networking solution specifications - HAVi, Jini, AV/C and UPnP. Two of these (AV/C and UPnP) are implemented partially for a system allowing a TV to configure an AudioNideo Receiver (AV/R) remotely on the network (a process known as remote configuration). The two implementations are then more closely investigated and several implementation differences in the approach between the remote configuration method of device configuration and other methods of device configuration are discerned. These different approaches are then categorised into one of two theoretical models of communication for configuring devices on home entertainment networks - the Rendering model and the Programmed model. By classifying a particular method of device configuration into one of the two models, manufacturers can quickly determine the inherent strengths and weaknesses of that method , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
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The role of cellulases and glucohydrolases in the solubilisation of primary sewage sludge
- Authors: Ngesi, Nosisa
- Date: 2002 , 2013-05-09
- Subjects: Sewage sludge , Sewage sludge digestion , Cellulase , Glucosidase inhibitors , Hydrolases , Sulfates
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4080 , http://hdl.handle.net/10962/d1007454 , Sewage sludge , Sewage sludge digestion , Cellulase , Glucosidase inhibitors , Hydrolases , Sulfates
- Description: Biological sulph ate reduction has been identi fied as a potentially valuable process for removing sulphate and heavy metals from indllstrial effluents. The role of sulphate reducing bacteria (SRB) in this process has attracted the attention of biotechnologists and recently of enzymologists due to its fundamental properties and possible role in AMD bioremediation. These obligatory anaerobic sulphate-reducing bacteria are commonly known to dissimilate sulphate for energy. Under anaerobic conditions SRB oxidize simple organic compounds such as lactic acid with the sulphate and thereby generate hydrogen sulphide (a stTong reducing agent) and bicarbonate ions. The hydrogen sulphide in turn reacts with contaminant metals contained in AMD and precipitates them out of solution as metal sulphides. Bicarbonate ions neutralize AMD by reaction with protons to form carbon dioxide and water. Organic matter in the municipal sewage sludge has been identified as a potential source of electron donors for su lphate reduction. However, this organic matter is in the polymeric form that cannot be util ised by SRB. The latter depend on the activities of other hydrolytic bacteria for the degradation of complex polymers. Hence the availability of these monomeric substrates is a major factor, which may constrain further process development and is considered a rate-limiting step. Thi s study is therefore undertaken to investigate the bacterial glucohydrolase enzymes involved in the digestion of the polysaccharides present in the sewage sludge with specific interest in cellulases and/or p-glucosidase enzymes. The goals of the research are to: isolate, identify, purify and quantify these enzymes; study their distribution with respect to time, pH, and temperature; maximize and quantify the hydrol ys is products; study whether sulphide and sulphate have an enhancing or an inhibitory effect on the activity of enzymes; optimize the enzyme activity against substrate and/or product inhibition and soluble heavy metal salts. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
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- Date Issued: 2002