An investigation of source rocks and depositional environments on acid mine drainage in South African coal mines: a comparison of the main Karoo basin and sub-basins.
- Authors: Ncube, Lindani
- Date: 2015
- Subjects: Mine drainage -- Environmental aspects -- South Africa , Coal mines and mining -- Environmental aspects -- South Africa , Acid mine drainage -- Environmental aspects -- South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/19556 , vital:43139
- Description: The coal deposits have been and continue to be the primary source of energy in South Africa. The continuous use of coal presents many challenges that includes genesis of acid mine drainage (AMD) which is as a result of the oxidation of predominant pyrite (FeS2) and other sulphides. The aim of this study was to investigate the role of source rocks and their depositional environments on AMD generation in South African coal mine environments. Five collieries from five coalfields were selected as case studies: Brandspruit in the Highveld, Vaalkrantz in the Vryheid, the Elitheni in the Molteno-Indwe, the Arnot in the Witbank and the Malatleng Exploration Project in the Waterberg Coalfields. Brandspruit, Vaalkrantz and Elitheni Collieries are located in the Main Karoo Basin, while the Witbank and the Waterberg Coalfields are located in Sub-Basins. The study investigated a variety of indices such as palaeo-depositional environments, mineral assemblages, geochemical signatures, water quality parameters, acid base accounting (ABA) and water leach tests for the coal and associated non-coal strata. An effort was made to establish the relationship between the mineralogy of the studied lithologies and the associated water quality. The study resulted in delineation of detrital and diagenetic rock components and interpretation of source area of rock types and the origin and timing of diagenetic alterations. Sandstone units are prevalent, except in the Waterberg Coalfield where mudstones are prevalent. Classifications of the mineralogical composition with descriptive adjectives yield the rock names arkose to sub-arkose categories in the Main Karoo Basin, and sub-arenites to quartz arenites in the Sub-Basins with the sandstones of recycled origin. Further, the sandstones of the Main Karoo Basin are of mixed provenance whilst those of Sub-Basins represent cratonic interior provenance. Sandstone from the Main Karoo Basin generally exhibit high concentrations of feldspars, which favour either high relief, arid or arctic climates with less chemical weathering at the source area. The presence of glauconite in sediments of the Main Karoo Basin attests to a marine continental shelf depositional environment. Sediments of the Main Karoo Basin have high contents of tadpole-shaped pyrite in coal and non-coal strata as compared to sediments of the Sub-Basins. The observed pyrite is ascribed to early diagenetic origin, and is closely related to the generation of acid mining drainage. The sediments have experienced an involved sequence of diagenetic alterations. The alterations considered to be typical for sandstones in the Main Karoo Basin are calcite cementation, feldspar dissolution, kaolinite infilling, pyrite grain coatings, albitization and pressure solution; whereas, quartz overgrowth and clay matrix filling are characteristics of sediments of Sub-Basins. The sequence and distribution of these alterations are related to the source mineral composition, depositional environment, stratigraphic relationships and burial history of the sediments. A direct link exists among the depositional environments, the mineral assemblages and the geochemical compositions of the lithologies. SiO2 is the dominant major oxide and is abundant in coals from coalfields located in the Sub-Basins. Si, Al, Fe, Ca, S, Mg, K and Na show strong association with their discrete minerals. The sandstones are substantially enriched in elements that are chemically immobile and associated with terrigenous influx, such as SiO2, Al2O3, and TiO2. The observed high contents of SiO2 are probably due to source rocks and silicification. SiO2, Al2O3 and TiO2 are related to clay and heavy minerals, with elevated Fe2O3 (Total) content in sediments of the Main Karoo Basin ascribed to sulphidization. Sediments from the Main Karoo Basin are enriched in both Na2O and K2O due to albitization and muscovitization. Substantial concentrations of Ba, Rb and Zr are in accordance to the high amount of phyllosilicates and heavy minerals. Muscovitization contributes to the correlation of Rb and Ba with K2O. The shales are substantially depleted in SiO2, CaO, MgO, Na2O, K2O, TiO2 and Fe2O3 due to weathering and diagenetic alteration, but are enriched in Al2O3 and P2O5. The ABA test clearly indicates that sandstones from the Main Karoo Basin have a potential of generating AMD as they contain sufficient pyrite to generate acid, with the final pH values of the samples turning acidic upon complete oxidation of pyrite. On the contrary, sediments of SubBasins contain sufficient calcite that serves to limit the amount of acid generation. Both sandstone and coal from collieries representing the Main Karoo Basin are characterised by elevated contents of S percent in comparison to coal from collieries representing the Sub-Basins. In general, the quality of water is as a result of a combination of complex geochemical interactions that involves various ions from different sources. Water leaching test shows that the leachates have varied chemical compositions with pH values in the range of 4.5-9 for the sandstone, and 2– 8.9 for the coal leachates. Variations in the pH values are attributed to regional phenomena controlled by the mineralogical and hydrological environments. Furthermore, the variation in pH is ascribed to the presence of acid forming pyrite and acid neutralizing carbonate minerals that are highly reactive in the mining environment. Elements Na, Ca, Mg and K occur in non-compliant concentrations in both coal and non-coal leachates indicating their abundance in all of the lithologies. Na enrichment in the lithologies is associated with albite, clay minerals and Al-Ksulphate coatings. Elements Fe, Al, Cd and Pb are easily leached from the lithologies. According to the equilibrium model, gibbsite, cuprite, diaspore and boehmite are the supersaturated minerals in the lithologies. Influencing factors such as the mineralogical composition of rocks are reflected in the wide variation of pH, TDS, EC and the ion concentrations of the studied water samples. The pH of the studied areas is neutral to alkaline. High levels of TDS and EC are observed in the Brandspruit Colliery, which is due to dissolution of soluble salts from the rock sequence that the water passes through. The anion chemistry shows the dominance of SO4 2- in the surface and groundwater of Brandspruit, Vaalkrantz and Elitheni Collieries, whereas HCO3 - dominates in the Arnot Colliery. SO4 2- is ascribed to the oxidative weathering of pyrites. Cldominates in groundwater from the Arnot Colliery and the Waterberg Coalfield. The cation chemistry is dominated by Na+ in the surface and groundwater of the Brandspruit, Vaalkrantz and Elitheni Collieries. Mg2+ dominates in groundwater from the Arnot Colliery, while K+ dominates in the Waterberg Coalfield. Fe is highly enriched in water from the Brandspruit Colliery, and is linked to the oxidation of pyrite. Carbonates are the supersaturated minerals in the Sub-Basins whilst sulphates are supersaturated in the Main Karoo Basin. The research shows that variations in regional mineral distribution is a result of a palaeo-deposition environment that was of marine nature for the coal sequence in the Main Karoo Basin and of fresh water for the coal sequence in Sub-Basins. A direct link therefore exists between depositional environments, mineral assemblages and whole rock geochemistry. It can be concluded that AMD is directly linked to pyrite and other sulphides, the coal mines located in the Main Karoo Basin have the possibility to deteriorate surface- and ground-water quality and to generate AMD during the mining processes; coal miners need to seriously consider applying environmental protection measures when mining coal in the Main Karoo Basin. Whereas, coal mining in the Sub-Basins has low possibility of generating AMD and pollution. , Thesis (PhD) (Geology) -- University of Fort Hare, 2015
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- Date Issued: 2015
Assessing public administration implications of the use and disposal of agro-chemicals in A2 farms in Zimbabwe : a case study of Chirumhanzu District
- Authors: Matunhu, Viola
- Date: 2015
- Subjects: Agricultural chemicals , Hazardous waste treatment facilities , Pesticide waste
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/26481 , vital:65471
- Description: This study is concerned with use and disposal of agro-chemical in A2 farms in Zimbabwe with specific reference to Chirumhanzu District. The study is located in the field of public administration. A transformational mixed research design was employed in the collection, analysis and interpretation of the field data. The study involved farm employees in 21 A2 farms that use agro-chemicals to enhance farm productivity. Non probability sampling techniques were employed to select the participating farms. Interviews, questionnaires, literature search, and observation where the main data collection instruments. A total of 150 purposively selected employees drawn from 21 participating farms participated in the study. The findings of this empirical study, which uses the terms I, the researcher, and the study interchangeably, were that there is poor use and management of agro-chemicals in the area. Most farm employees do not adhere to instructions on use and disposal of the chemicals and there is a weak monitoring and evaluation of the use and disposal of agro-chemicals on the farms. Yet, most of these chemicals are carcinogens. Farm employees need to be trained on personal and public health implications of poor management of agro-chemicals. Labels on containers that store chemicals need to be written in both English and vernacular, which is not the case in the district. Labels on most of the chemicals on the farms studied are written in English and technical terms are used. Although, most of the employees on the farms are literate, they find it difficult to understand the jargon on labels. , Thesis (PhD) -- Faculty of Management and Commerce, 2015
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- Date Issued: 2015
Establishment of human OCT4 as a putative HSP90 client protein: a case for HSP90 chaperoning pluripotency
- Authors: Sterrenberg, Jason Neville
- Date: 2015
- Subjects: Induced pluripotent stem cells , Heat shock proteins , Stem cells , Transcription factors , Molecular chaperones
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/194010 , vital:45415 , 10.21504/10962/194010
- Description: The therapeutic potential of stem cells is already being harnessed in clinical trails. Of even greater therapeutic potential has been the discovery of mechanisms to reprogram differentiated cells into a pluripotent stem cell-like state known as induced pluripotent stem cells (iPSCs). Stem cell nature is governed and maintained by a hierarchy of transcription factors, the apex of which is OCT4. Although much research has elucidated the transcriptional regulation of OCT4, OCT4 regulated gene expression profiles and OCT4 transcriptional activation mechanisms in both stem cell biology and cellular reprogramming to iPSCs, the fundamental biochemistry surrounding the OCT4 transcription factor remains largely unknown. In order to analyze the biochemical relationship between HSP90 and human OCT4 we developed an exogenous active human OCT4 expression model with human OCT4 under transcriptional control of a constitutive promoter. We identified the direct interaction between HSP90 and human OCT4 despite the fact that the proteins predominantly display differential subcellular localizations. We show that HSP90 inhibition resulted in degradation of human OCT4 via the ubiquitin proteasome degradation pathway. As human OCT4 and HSP90 did not interact in the nucleus, we suggest that HSP90 functions in the cytoplasmic stabilization of human OCT4. Our analysis suggests HSP90 inhibition inhibits the transcriptional activity of human OCT4 dimers without affecting monomeric OCT4 activity. Additionally our data suggests that the HSP90 and human OCT4 complex is modulated by phosphorylation events either promoting or abrogating the interaction between HSP90 and human OCT4. Our data suggest that human OCT4 displays the characteristics describing HSP90 client proteins, therefore we identify human OCT4 as a putative HSP90 client protein. The regulation of the transcription factor OCT4 by HSP90 provides fundamental insights into the complex biochemistry of stem cell biology. This may also be suggestive that HSP90 not only regulates stem cell biology by maintaining routine cellular homeostasis but additionally through the direct regulation of pluripotency factors. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2015
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- Date Issued: 2015
Modification and application of the decentralised wastewater treatment technology for greywater treatment to reduce water needs
- Authors: Ngqwala, Nosiphiwe Patience
- Date: 2015
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/193509 , vital:45338
- Description: Water is a scarce resource that is being acknowledged as a limiting factor to further social- economic growth and development. Demand for freshwater is increasing with corresponding increases in human population, industrial and agricultural activities. Alternative sources, such as greywater and rainwater are often polluted. Though greywater can be used for non-potable purposes, such as irrigation, it still requires some measures of treatment to improve its quality. To improve on greywater quality to facilitate its reuse, decentralised wastewater treatment technologies carry a great potential as complementary and alternative means of wastewater management particularly in peri-urban areas. Five research goals are addressed in this thesis: (i) to monitor the performance of Fly Ash Lime Filter Tower (FLFT) in the treatment of greywater; (ii) to modify the Fly Ash Lime Filter Tower in the treatment of greywater in order to reduce the pH of the greywater, and improved on the reduction of chemical oxygen demand (COD) and coliform counts; (iii) to investigate the potential of the reuse of greywater for irrigation; (iv) to undertake a techno analysis of the FLFT system for commercial use; and (v) to evaluate the use of hydrogen-sulphide (H2S) test kit to monitor faecal contamination of various water sources using a multidisciplinary approach. The modification of the FLFT indicated good treatment efficiency, reducing the concentrations of COD, chlorides, nitrates, ammonia and sulphate by 82.6%, 60.4%, 72.9%, 60.5%, and 53.9%, respectively; while the average pH was at 8.3. Greywater contains nutrients that are beneficial to the growth of most plants. Growth variables included biomass, stem height, number of leaves and number of vegetables harvested. Soil analysis showed no effects of the treated greywater on soil physico-chemical and microbial quality with bulk density 2.0g/cm3, average pH 7.4, total phosphorus 0.16mg/L 8, faecal coliform 0.3 CFU/100 ml. The tomatoes had high biomass and dry weight (150 g; 33g) than beetroot (35 g; 15 g). Crops irrigated with greywater significantly grew faster compared with those irrigated with tap water. The community approach highlighted the value of knowledge management in greywater reuse. It highlighted the importance of creating an institutional knowledge in water management using the H2S kit. The techno-economic analysis was used to evaluate key factors and the activities that are relevant to develop a sustainable FLFT in order to gain insights into the possibility of developing, and incorporating a business model framework to support decision making in value creation and value capturing during the research and the scaling up of the system. By this, a long term perspective to accomplish sustainable FLFT service businesses can be achieved. , Thesis (PhD) -- Faculty of Pharmacy, Pharmacy, 2015
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- Date Issued: 2015
Study of the biotransformations and microbiological properties of cymbopogon citratus
- Authors: Ajayi, Emmanuel Olusegun https://orcid.org/0000-0002-0838-4948
- Date: 2015
- Subjects: Lemongras , Essences and essential oils
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/19737 , vital:43197
- Description: Variations in the essential oil yield, chemical composition and kinetics of chemical transformation, antibacterial, and antioxidant properties of the Cymbopogon citratus cultivated in Alice, Eastern Cape of South Africa, over a period of 12 months using the solvent-free microwave extraction and the modified forms of conventional hydrodistillation methods have been evaluated. The modified forms involve variation in the pH medium to effect extraction and to obtain the whole leaf extracts of Cymbopogon citratus (lemongrass). The GC-MS analyses of the essential oils revealed the presence of 10, 11, 13, and 9 principal compounds in the microwave, extraction, hydrodistillation (water-distilled), hydrodistillation (aciddistilled and hydrodistillation (base-distilled), respectively with citral being the prominent compound in all the various extraction methods, with the water-distilled method having the highest cumulative citral content under the period specified. Each of the components of the oils varied in quantity and quality of yield at different points of the year. Different extraction methods produce different compounds. Increase in the amount of citral content was observed during the maturation stage of Cymbopogon citratus in all the extraction methods. Quantitative evaluation of antibacterial activity, minimum inhibitory concentration (MIC) values were determined on the oils and extracts of Cymbopogon citratus using agar dilution method. The essential oils obtained using all the methods of extraction showed activity against all the tested bacteria at a concentration of 10 mg mL-1. The minimum inhibitory concentrations for the acid-distilled varied between 1.25 and 5.0 mg mL-1, while those obtained by both water- and base-distilled showed equal activity on the microorganisms with the MIC ranging between 2.5 and 10 mg mL-1. The microwave extraction showed the least activity with the MIC of 10 mg mL-1. This however suggested that the oils obtained through acid-distillation showed the greatest activity than all other methods of extraction. Activity of the various extracts on bacteria showed that the ethanol extract had the highest activity on the tested organisms with MIC ranging between 0.625 and 1.25 mg mL-1. This was closely followed by the acid-extract (1.25 and 5.0 mg mL-1), methanol extract (1.25 and 10 mg mL-1), acetone extract (2.5 and 5.0 mg mL-1), and base extract (5.0 mg mL-1). Both cold water and hot water extracts showed the least activity of MIC, >10 mg mL-1. The antioxidant and free-radical scavenging activity of the obtained oils and extracts were tested by means of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH+) assay, [(2,2ˊ-azino bis-(3-ethylbenzothiazoline-6-sulfonic acid)] (ABTS), nitric oxide and ferric reducing power assays. The oils and extracts showed DPPH radical scavenging ability, but not as high as the standard drugs. The base extract showed a higher reducing power than the standard drug, rutin. There were significant differences in the phytochemicals contents of the various leaf extracts. The acetone extract has the highest flavonol, proanthocyanidin, and alkaloid contents. The ethanol extract showed the highest amount of phenolic content with the acid extract, having the least. Thin layer chromatography (TLC) and column chromatography was employed to obtain different fractions of extracts using four eluent solvent systems of varying polarities: toluene, petroleum ether, hexane and ethyl acetate and sprayed with anisaldehyde. A single, visible spot of B-fraction was developed, collected and analyzed as 1-methyl-2,4,5- trinitroimidazole with renown valuable properties. , Thesis (PhD) -- Faculty of Science and Agriculture, 2015
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- Date Issued: 2015
The design and evaluation of targeted patient-centred health information to improve knowledge and behavioural outcomes in tuberculosis patients with limited literacy
- Authors: Patel, Sonal
- Date: 2015
- Subjects: Tuberculosis Patients , Health literacy , Patient education , Communication in medicine , Picture-writing
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/194071 , vital:45420 , DOI 10.21504/10962/194071
- Description: South Africa carries a significant TB burden as evidenced in the 2013 statistics which report 450 000 new active TB cases and 890 000 TB-related mortalities. For successful treatment outcomes, 90% adherence is necessary, but many patients prematurely discontinue treatment due to poor knowledge and understanding of their complex TB medicines. Patient education is pivotal in improving knowledge, health literacy and behavioural outcomes such as health information seeking, self-efficacy and adherence. In the under-resourced South African healthcare system, time and capacity to adequately counsel patients are limited. The value of written medicine information (WMI) to supplement the verbal information provided by healthcare professionals (HCPs) has been widely investigated but minimal South African research is available. Current WMI distributed in South Africa is mainly generated by pharmaceutical manufacturers and is complex, incomprehensible and undesirable to patients. TB-related WMI focuses mainly on the disease, with little information relating to TB medicines and their use. The overall aim of this project was to improve patient knowledge about their TB medicines through the use of a simple illustrated patient information leaflet (PIL). Objectives to achieve this aim included: investigation of the medicine information seeking behaviour (MISB) of long term patients attending public health sector facilities; the development and validation of a medicine literacy test (MLT) to identify patients with limited health literacy requiring additional support and counselling; the development and evaluation of a patient-centred illustrated PIL for first-line TB treatment; the assessment of self-efficacy and adherence using modified versions of the HIV Treatment Adherence Self-Efficacy Scale (HIV-ASES) and Morisky 8-item Medicine Adherence Scale (MMAS-8), respectively, and the investigation of the impact of the PIL on patient knowledge and these health-related behaviours. Six focus group discussions (FGDs) conducted in 34 isiXhosa-speaking patients with limited formal education taking long-term treatment explored themes related to information needs, information-seeking practices and awareness of and ability to utilize information sources. Codes were analysed and potential themes and subthemes were identified and refined. The findings of this study reflected a passive, disempowered patient due to both patient-related and systemic healthcare factors. Poor awareness of information sources, lack of health-related knowledge, stigma and lack of awareness of the importance of appropriate medicine-related knowledge contributed to a lack of information-seeking practice. Patients neither asked questions nor were encouraged to do so. All expressed an unmet need for information and a desire for receiving relevant, appropriate, written medicine-related information. Feedback from this phase of the study was used to inform the development of the targeted patientcentred PIL. A double-sided A4 PIL containing information about TB medicines was designed giving careful consideration to content, format and layout features. Twenty five pictograms were designed through a rigorous, iterative design process and were included in the PIL that was evaluated in a randomised control trial (RCT) conducted amongst 120 TB patients attending a high burden TB clinic in South Africa. Interviews were conducted in either isiXhosa or Afrikaans via a trained interpreter. Patients were randomly allocated to either a control (standard care) or an experimental group (standard care plus brief counselling using the PIL). Two interviews were conducted using a prepared questionnaire; one at baseline followed by a 4-week follow-up. Baseline data included demographics, medicine literacy test, health information sources, knowledge of TB medicines, self-reported adherence and self-efficacy. Data collected at the 4-week follow-up interview included TB knowledge, self-reported adherence, self-efficacy, opinion of TB medicine information and interpretation of pictograms. Data were analysed using t-test, correlations, chi-square and ANOVA tests at a 0.05 level of significance. The PIL was successful in improving patient knowledge of the disease, TB medicine-taking, side effects, drug-resistant TB and HIV and TB co-infection. At baseline, there was no significant difference in the overall mean percentage knowledge score between the control and experimental groups (p=0.074). At follow-up, the percentage knowledge score for the experimental group increased significantly from 59.0% to 84.6% (p<0.001) and showed a significantly higher score than the control group (p<0.001), displaying evidence of the impact of the PIL as a counselling tool on patient knowledge. The PIL generated a highly positive response in the experimental group who indicated that they had referred to the leaflet over the last month and that it had played an important role in improving their TB medicine-related knowledge. This was reflected in the experimental group knowledge score of greater than 80% for almost three quarters of the patients whereas only 14% in the control group achieved this score. Patients appreciated the inclusion of pictograms and strongly felt that they helped them to recall and understand the textual PIL content. The study found that patients want side effect information and, interestingly, did not perceive the presentation of side effects in pictorial form to constitute a risk factor for nonadherence. Use of the illustrated PIL (experimental group) resulted in a significant improvement in patient self-efficacy (p=0.002), but showed no effect on self-reported adherence (p=0.563). Neither self-efficacy nor adherence was influenced by gender, age or education. An education effect on knowledge was only observed in the control group at baseline. The newly developed MLT was shown to be a valid and reliable tool and a moderate, positive and significant correlation was noted between the MLT score and baseline TB medicine-related knowledge in both the control and experimental groups. As there is a paucity of studies investigating the influence of take-home written leaflets on TB medicine knowledge and on patient behaviour, this study represents a significant knowledge contribution. It is the first study to report the development and evaluation of a patient-centred PIL to address the dearth of available TB medicine information. The use of targeted user-friendly, illustrated information leaflets can be a valuable counselling aid to improve patient knowledge and self-efficacy, particularly among patients with limited literacy. However, careful consideration of the design and content, with input from the endusers at all stages of the process, will optimise its effectiveness. The proposed framework for the development and implementation of patient-centred health and medicines information in a developing country context presented in this thesis could be used as a theoretical basis for informing the development of effective information materials targeting other disease states. Local patients taking TB medicines identified nurses, WMI and media as their current sources of information but they expressed a strong desire to know more about their treatment. Targeted public health interventions that focus on medicine-taking information and behaviours and encourage patients to adopt a more active, questioning role in health consultations could improve health literacy and empower patients in their medicine-taking practices. , Thesis (PhD) -- Faculty of Pharmacy, Pharmacy, 2015
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- Date Issued: 2015
Main thesis title 2021: subtitle if needed. If no subtitle follow instructions in manual
- Authors: Mashinini, Peter Madindwa
- Date: 2015-03
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/53340 , vital:45138
- Description: Ti6Al4V alloy usage is increasing due to high demand from the aerospace and automotive industries as well as the field of medical implants. Therefore, identifying the most effective joining technique is critically important to ensure that optimum life can be achieved by welded components. This is especially important for the aerospace industry where fatigue life of the welded joints is vital. This research identified two relatively new joining technologies for Titanium sheet, namely, Friction Stir Welding (FSW),a solid-state process, and Laser Beam Welding (LBW),a fusion joining process. It was therefore vitalto conduct a systematic study of these two processes and compare results to illustrate which process attributes to static and dynamic properties. This investigation was accomplished by varying the process heat input for both FSW and LBW. The main parameters used to control process heat input were rotational-and traverse speed for FSW and laser power and traverse speed for LBW. In FSW, a reaction torque was used to describe the process energy in order to achieve the plasticised material condition. Preliminary work was done to establish the influencing factors for a successful weld which included tool optimisation but process optimisation was not discussed in elaborative detail. In LBW, traverse speed was identified as the critical control parameter to ensure good weld penetration. Weld width was recorded as it showed strong correlation to heat input rates. , Thesis (MA) -- Faculty of Engineering, the Built Environment and Technology, Mechanical Engineering, 2021
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- Date Issued: 2015-03
Perceptions regarding corporate citizenship behaviour in Zimbabwe
- Authors: Muzvidziwa, Itai
- Date: 2015-03
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/53396 , vital:45144
- Description: Corporate Citizenship (CC) has risen as a conspicuous term in the literature dealing with the social role of business. Citizenship‟s focal point is the rights and responsibilities of all members of the community. CC can be defined as the extent to which organisations undertake the compulsory economic, legal, ethical, and discretionary responsibilities imposed on them by their stakeholders. CC recognises organisations as legal persons with certain rights and responsibilities as members of a community. The upsurge in undertaking acts of social responsibility illustrates that CC tends to be a strategic measurement that investors use to consciously align ethical concerns with publicly held organisations. In Zimbabwe, some organisations have made some progress towards CC - yet a long journey lies ahead in promoting CC by both the private sector and the Government of Zimbabwe. Against this background, the following research question was addressed in this study: What are the perceptions regarding CC behaviour in Zimbabwe? This study has been motivated by the knowledge gap on CC as a dynamic and contextual response to internal and external environmental pressures and the shift in community expectations concerning the roles, responsibilities and accountabilities of businesses in Zimbabwe. The main objective of this study was to investigate perceptions regarding corporate citizenship behaviour in Zimbabwe. A hypothetical model shows various factors that may influence perceptions regarding CC behaviour in Zimbabwe. Three independent variables (internal factors, external factors and personal factors) were identified as variables that may influence perceptions regarding CC behaviour. The mediating variable (perceptions regarding CC behaviour) was also identified as a variable that have potential to affect the dependent variables (organisational performance, competitiveness, image and sustainability). Furthermore, seven null-hypotheses were developed to test the relationship between the independent, mediating and dependent variables. All these variables were clearly defined and operationalised with various items obtained from measuring instruments used in other similar studies. , Thesis (PhD) -- Faculty of Business and Economic Sciences, School of Management Sciences, 2021
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- Date Issued: 2015-03
Performance-based strategies for improving service quality in electricity regulation in developing countries: the Nigerian experience
- Authors: Obi, Chikwerem Ukaobasi
- Date: 2015-03
- Subjects: Electricity--Government policy--Developing countries , Public administration
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/24868 , vital:63665
- Description: Service quality is a relatively new concept in the regulatory lexicon. It has emerged as a critical factor in post-reform regulation of electricity distribution networks and it is a multi-dimensional concept in regulatory policy that connotes standard of performance in service delivery. Regulators establish performance standards by defining clearly the quality of service the customer deserves given the price paid. It is in recognition of the fact that customers are highly sensitive to the level of service delivered to them, and they value the speed and accuracy with which their requests are handled that have made service quality critical in the electricity value chain. The level of quality provided to individual customers is generally distributed over a range of values. Hence, regulators are mainly concerned with the protection of the worst-served customers and the possibility that a group of customers might receive unacceptably low levels of service quality. The major objective of this study is to ascertain how service quality regulation can improve electricity distribution in Nigeria. In doing this, the research gave a general overview of the study as an introduction in chapter one; it went on to review the available literature in chapter two. Chapter three conceptualizes the framework of the study by identifying the New Public Management (NPM) as a catalyst for effective regulation, followed by a case study of the Nigerian Electricity Regulatory Commission in chapter four. In chapter five, the study employed the Likert attitudinal scale sampling technique and the Data Envelopment Analysis (DEA) as the methodologies for data analysis in the research. The data presentation and interpretation were carried out in chapter six by presenting the results of the customer survey and outlining the key performance indicators (KPIs) based on the following three areas of service quality: technical indicators, financial indicators and customer-service indicators, which finally dovetailed into the summary, recommendations and conclusion in chapter seven. The performance of the privatized DISCOs was assessed by means of descriptive analysis by administering questionnaires, trend analysis and technical efficiency estimations using the Data Envelopment Analysis (DEA) techniques. The estimates were carried out by means of the Frontier 4.1 software and were based on three assumptions of returns to scale. The findings revealed that the average industry performance for DISCOs dropped from 95% before privatization to 82% after privatization. This relatively poor performance may well have been caused by the reluctance of the private investors, who now own majority shares in the DISCOs, to invest in the retrofitting and upgrading of the network infrastructure existing before they took over. The implication of this finding is not a condemnation of the recentlyconcluded privatization of the power sector in Nigeria, but probably the private investors’ desperation to recover their investment at the expense of public interest for quality service given that most of the investors acquired the utilities with shortterm funds. , Thesis (PhD) -- Faculty of Management and Commerce, 2015
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- Date Issued: 2015-03
A framework for continuing professional development of teachers in regular primary schools: towards the effective teaching of learners with special education needs in Zimbabwe
- Authors: Muguwe, Emely https://orcid.org/0000-0003-2156-8642
- Date: 2015-05
- Subjects: Teachers -- Training of , Teachers -- In-service training.
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/24794 , vital:63576
- Description: This study focused on Continuing Professional Development (CPD) needs of teachers in regular primary schools for the effective teaching of learners with special education needs in Zimbabwe. The motivation of the study emerged from concerns raised by stakeholders that teachers were inadequately prepared to teach learners with special education needs in general education classrooms. This study was underpinned by the post-positivistic paradigm which takes on both quantitative and qualitative approaches. The study also employed the survey design, which utilised the mixed methods approach. The accessible population comprised 93 primary schools and 1 457 teachers, 93 school heads and all education officers in the Gweru District of Zimbabwe. The researcher used purposive and disproportional random sampling. Ten schools were purposively selected from a population of 93 schools in the Gweru District. One hundred and fifty teachers (10percent of the population) which translated into 15 teachers from each school, were selected from the 10 schools through disproportional stratified random sampling in order to include both male (n=69) and female (n=81) teachers in the study. Semi-structured questionnaires, semi-structured face- to- face interviews and focus group discussions are the data collection methods which were used in this study. Data were presented, analysed and discussed, starting with demographic data in the first section, followed by quantitative data which were presented concurrently with corresponding emerging themes from qualitative data. The data collected via the questionnaires were coded and key-punched for analysis. Data were presented in tables, bar graphs and pie charts. Findings of the study revealed that there is a dire need for knowledge and skills in SEN among teachers in regular schools. Teachers needed to be prepared for a paradigm shift of the inclusive era. Teachers also needed to identify their own needs to ensure that relevant and preferred areas were covered. Findings revealed that teachers preferred well-structured CPD which is facilitated by an expert and CPD held in their own schools, where good practices are shared with workmates. Findings also confirmed the availability of policy circulars in schools, although some teachers expressed that they were not aware of such circulars. There were no specific days allocated specifically for school CPD. Most teachers were not availed with the opportunity to attend out-of-school based workshops; and cascading of information led to dilution of original ideas. There was lack of adequate mentoring among qualified teachers. Teachers preferred the standards-based model for promotion purposes although it was limiting in terms of teachers’ learning. The training model was viewed as a productive way of quickly in-servicing teachers relative to its cost. The communities of practice model and transformative model were not being utilised in schools due to national policies that govern teachers. Findings also revealed that teachers faced major challenges such as funding of CPD, getting information on CPD opportunities and time to engage in CPD activities. Teachers reeled with a lot of pressure resulting in burn-out as a result of large classes. Although staff development meetings were held in schools, they were mostly administrative and nothing definite was being done to mitigate the challenges which teachers were facing in accessing CPD opportunities. Teachers opted for a CPD framework which would give them more information and more opportunities for CPD on SEN, better access to teaching materials and more opportunities to work with experienced practitioners in SEN. Teachers preferred a framework based on a variety of CPD models, more school-based CPD rather than out of school -based CPD. The researcher concluded that teachers in regular schools were not equipped to teach learners with special education needs in the mainstream. The Ministry of Primary and Secondary Education was not employing the best models in preparing teachers to be effective. Teachers were facing challenges such as, funding, unavailability of information and time in accessing CPD opportunities. The study recommends that The Ministry of Primary and Secondary Education should put in place provisions to meet the CPD needs of teachers. Teachers should be fully involved in the identification of CPD needs. It was also recommends that school heads needed CPD on SEN for them to be able to guide teachers properly and to be supportive of the policy. Besides national policies, schools should design CPD policies specifically for their respective schools, in line with national policies. Andragogy principles, Wenger’s social learning theory and Vygotsky’s perspective among others, should underpin the CPD framework. The study recommends an alternative CPD model which would utilise a combination of transmissive, transitional and transformative models and modes of delivery as lenses in meeting the CPD needs of teachers in the context of SEN. , Thesis (PhD) -- Faculty of Education, 2015
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- Date Issued: 2015-05
Behaviour and trophic ecology of oceanic triggerfish (Canthidermis maculata) and rainbow runner (Elagatis bipinnulata) associated with floating objects in the open ocean
- Authors: Forget, Fabien Rocky Gilbert
- Date: 2016
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/193531 , vital:45340
- Description: The oceanic triggerfish (Canthidermis maculata) and rainbow runner (Elagatis bipinnulata) are epipelagic species that commonly associate with floating objects throughout the world’s tropical oceans. Besides tunas, these two species often form the bulk of the aggregation and are major non-target species (bycatch) incidentally captured at fish aggregation devices (FADs) by tropical tuna purse seiners. Despite being abundant, little is known about their basic biology, ecology and associative behavior with floating objects. This thesis aims to address knowledge gaps in their associative behavior and ecology at floating objects and attempts to explore potential bycatch mitigation methods. Acoustic telemetry was used to characterise several aspects of the two species’ behavior at floating objects. Fish were captured and tagged at drifting FADs in the core of the western Indian Ocean tuna fishing grounds. Prolonged remote observations were obtained through satellite linked receivers which provided fine-scale data on the behavior of oceanic triggerfish (n= 46 919 cumulated observation days) and rainbow runner (n= 24 538 cumulated observation days). The two species remained associated with the same floating object for periods extending up to several months. The mean residence time estimated using a survival analysis was 65 days for oceanic triggerfish and 94 days for rainbow runner. A distinct diel pattern in association was observed; the two species were closely associated to the FAD during the night and increased their home range during the day while performing short excursions (oceanic triggerfish mean: 2.0 hours ±1.6 SD; rainbow runner mean: 2.4 hours ±2.2 SD) away from the FAD. Similarly, distinct patterns in the vertical movements and locomotory activity (measured using accelerometer tags) were observed as the two species increased their vertical movements and activity levels during the day. Generally, their vertical movements were largely restricted to the mixed layer (< 60 m). At night, the two species remained close to the surface (0-5 m) where they appear to be in a resting state. An interesting behavioural switch in activity levels and vertical distribution was observed for oceanic triggerfish which coincided with a change in the environment as the FAD drifted close to a cold-core cyclonic eddy. Ambient light appears to be the key stimulus triggering the observed diel behavioural patterns. species-specific vulnerability for target species, skipjack (Katsuwonus pelamis), yellowfin (Thunnus albacares), bigeye tuna (Thunnus obesus) and non-target species, including silky shark (Carcharhinus falciformis), oceanic triggerfish, and rainbow runner, to the purse seine fishing gear were investigated. Hourly presence rates at FADs over 24 hours were examined to assess whether the capture rate of non-target species could be reduced at specific times during the day. Silky sharks displayed a similar associative pattern to that of targeted tunas. Moreover, the vulnerability of both target and non-target species were close to the maximum during the period of behavioural transitions at sunrise when the majority of the fishing sets are made. As such, a change in set time in the western Indian Ocean does not appear to be a feasible method to reduce capture rates of non-target species. Stomach content and stable isotope analysis were conducted on oceanic triggerfish (stomach n = 152, isotope n = 65) and rainbow runner (stomach n = 156, isotope n = 71) incidentally captured individuals at FADs by purse seiners. Typical FAD-associated prey items represented a minor component of their diet as they predominantly foraged on zooplankton and micronekton in the water column, suggesting that oceanic triggerfish and rainbow runner do not associate to floating objects for direct trophic advantages. Overlap in their dietary and isotopic niches indicates an intermediate level of competition. Overall, the spatial and trophic ecology of both species are remarkably similar and prolonged associations with FADs indicates that floating objects play a significant ecological role in the pelagic environment for the two species. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2016
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- Date Issued: 2016
Soil microbial properties and apple tree performance under conventional and organic management
- Authors: Meyer, André Harold
- Date: 2016
- Subjects: Soil management South Africa Western Cape , Agricultural chemicals Environmental aspects , Soil microbiology South Africa Western Cape , Vesicular-arbuscular mycorrhizas , Enzymes Biotechnology , Apples Organic farming South Africa Western Cape
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/64545 , vital:28557
- Description: Conventional (CON) soil management that permits the use of agrochemicals is currently the most common form of management in Western Cape deciduous fruit orchards. There is increasing pressure to minimise or eliminate synthetic agrochemical usage due to its potentially harmful effect on the environment, particularly to non-target soil microorganisms, and to the functions and processes they perform or mediate. In apple orchards, organic (ORG) practices exclude the use of synthetic pesticides and herbicides making use instead of organic fertilisers and naturally derived products as defined by organic certification programs. ORG practices aim to improve nutrient availability, yield, and long-term orchard sustainability relative to CON orchard management practices. If ORG and CON orchard floor management practices affect orchard ecosystems differently, such differences should be measurable in terms of differences in microbiological parameters. In this thesis it is hypothesised that ORG practices would induce positive soil microbiological responses in Western Cape apple orchards relative to CON practices, and by inference general soil health and apple tree performance. To test this hypothesis a polyphasic approach was adopted. This involved measurement of soil microbial activities and functional diversities, by enzyme activity (using colorimetric assays) and carbon-substrate utilisation (using the BIOLOG™ system), respectively. With reference to the enzyme analyses, the performance of a literature-validated, enzyme-based soil health index was also tested. The analyses were supported by coarse-level comparisons of the magnitude of bacteria, fungi, actinobacteria and total heterotroph populations using traditional culturing techniques (dilution plating on growth media). The extent to which the microbial status differed between the applied ORG and CON treatments was thought likely to reflect such treatment-induced variables as soil nutrient status, apple tree nutritional response, tree growth and yield, all of which were determined. Because the root systems of deciduous fruit trees commonly extend to depths >60 cm in well-prepared soils, microbial enzyme activities in the soil depth intervals corresponding to the lower rootzone, were also investigated. This research was carried out in a randomized field trial. Finally, to gain a broader understanding of the effects of contrasting soil management systems on soil microbiology under a greater variety of environmental conditions, arbuscular mycorrhizal (AM) fungal dynamics were explored in a survey of commercial apple orchards. These orchards were selected to span the range of environmental conditions that occur in the apple production areas of the Western Cape. Orchard soils under ORG management promoted richer microbial ecosystems, and appeared to be better able to sustain community metabolic diversity and, by inference, the functions mediated by soil microbial communities, than those under CON management. This implies that ORG approaches possibly afford a better option to sustain critical ecosystem functions than CON management. This possibly explains why use of straw mulches and compost in accordance with ORG practices, compared with CON practices, promoted β-glucosidase, acid phosphatase and urease activities rather than affecting the abundance of the micro-organisms that produce these enzymes. Enzyme activities in the 0–30 cm soil intervals were also more effectively promoted by ORG than CON practices, although no differences were observed at lower depth intervals. ORG practices promoted functional AM associations more effectively than CON practices, but the abundance of glomalin, a beneficial by-product of AM fungi, was unaffected. The greater enzyme activities and higher root colonisation levels in the ORG treatments probably contributed to improved nutritional effects that caused greater vegetative growth, but lower yields, in the ORG treatments. Yield suppression was conceivably due to excessive vegetative growth induced by oversupply of compost and the mineral nutrients contained therein. The survey of Western Cape apple orchards suggested that neither glomalin nor root colonisation bore any specific relationship to production area, cultivation practice, scion x rootstock combination, or, in the case of root colonisation, with any chemical parameters. However, the effect of season on glomalin was conclusively shown, being higher in summer than in spring, as was the lack of any effect of year on glomalin and root colonisation. Collectively, these results showed that ORG soil management promote soil microbiology, soil nutrient status, and apple tree performance compared to CON management. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2016
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- Date Issued: 2016
The implementation of foundational provision programmes in a rural based University in South Africa: implications for student academic development practices
- Authors: Marhaya, Luyanda
- Date: 2016-05
- Subjects: Education, Higher -- South Africa , College student development programs
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/24706 , vital:63529
- Description: The purpose was to establish how foundational provision programmes were implemented in a rural based university in South Africa and implications to student development practices. The study was located in the- post- positivism research paradigm, followed a mixed methods research approach and utilised a concurrent triangulation research design. For the qualitative component of the research, participants (academics and Coordinators of the foundation programmes and senior students who had enrolled through foundational provision programmes) were purposively sampled. The sample for the quantitative data comprised all the students who enrolled in foundation provision programmes between the years 2008 to 2011 and mainstream students who had enrolled between the years 2009 and 2012. For qualitative approach, focus group discussions were conducted, semi-structured interviews and document analysis. Quantitative data was sought from university institutional data storage warehouse, HIGHER EDUCATION MANAGEMENT INFORMATION SYSTEM (HEMIS). For qualitative approach, the data analysis for all data collection methods was done through thematic analysis. For quantitative approach, a longitudinal analysis was conducted to track and compare two cohorts of mainstream and foundation students in terms of retention, attrition and graduation rates. Quantitative data were analysed statistically by use of descriptive and some inferential statistics. Main findings were that: there was inadequate capacity institutionally for developed systems of admission for students entering foundation programmes, lack of curriculum compliance by different lecturers and lack of knowledge of curriculum reforms by lecturers who teach in foundation level, funding for foundation provision programmes was not adequate and lacked transparency. However, there were adequate recruitment processes in the university for lecturers that teach in foundational foundation provision programme and there was no government interference into how foundation programmes are governed. The study also found that students had experienced the student development practices positively, however, these practices were not enough, and equally most responsive student development practice did not exist at the institution under study. The study also found that there had been consistent funding from government but there was no proper expenditure systems in the institution. The study found that, in terms of graduation rates, the two groups compared relatively the same as there was no significant differences in patterns and trends that were observed. However, retention rates suggest that, in the first year, the two groups perform relatively the same, thereafter, there is a significant difference into how the two groups perform as they proceed to other years, especially the second year, where the mainstream cohort showed better performance than their foundation provision programme counterparts. Consequently, high attrition rates were experienced by foundation provision students than mainstream students, this was also experienced a lot more during the second year and third year transition. The implication of these findings was that due to institutional factors that affect the implementation of foundation programmes, these had notable impact on the attrition and dropout rates on foundation provision students. In addition, due to a lack of responsive student development practices, foundation programmes compared relatively low to their mainstream counterparts in retention. The study has recommended a model that can be implemented in the institution. The first component of the model is to put an admission system in place. Institution has to establish a platform where faculties present development plans for foundation provision programmes. In addition, there should be a dedicated Accountant managing finances of the foundation programme. The institution should establish the Tracking and Monitoring student development practice, establish Writing Centres and Learning Communities and employ more people in the Centre for Higher Education, Teaching and Learning department to ensure full implementation of existing student development practices and those that will be established. , Thesis (PhD) -- Faculty of Education, 2016
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- Date Issued: 2016-05
Cultural and social factors affecting crop production at Gqumahashe and Melani, Alice District
- Authors: Komanisi, Mzwandile Paul 0000-0003-0866-666X
- Date: 2016-06
- Subjects: Sharecropping , Food crops
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/23023 , vital:55001
- Description: Over the years, sharecropping and work-parties have been seen as variables that maintain social cohesion among people and maximize agricultural production. This study seeks to validate the authenticity of this assertion in the context of two neighbouring villages. Although there are other variables that affect crop production in the study areas, Lower Gqumahashe and Melani, in the light of time constraints and the insignificant impact of these variables, the study focused only on sharecropping and work-parties. The study adopted empirical research design. The researcher realised that empirical research design would offer him an opportunity for intense or prolonged contact with informants in order to have a holistic picture of their behaviour. The researcher did not choose theoretical research design because it would not allow him to have an extensive interaction with informants since it relies on secondary data. The findings of the study suggest that sharecropping and work parties are the main variables that hinder the rate of crop production in the study areas. However, there are other secondary variables hindering crop production but they have insignificant impact. These are clan and kinship relations, political structure, religion and social identity. This study concludes that although local informants were in favour of sharecropping and work-parties in the past, they have discontinued them due to exploitation and hoodwinking. , Thesis (PhD) -- Faculty of Social Science and Humanities, 2016
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- Date Issued: 2016-06
Entrepreneurial development paths and livelihood strategies in smallholder irrigation schemes in the Eastern Cape province, South Africa
- Authors: Gidi, Lungile Sivuyile https://orcid.org/0000-0002-2896-2709
- Date: 2016-07
- Subjects: Farms, Small , Irrigation farming -- Economic aspects
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/24906 , vital:63670
- Description: South Africa has implemented several successful rural poverty relief initiatives; however, poverty continues to strain rural development efforts. The aim of the study was to analyse the entrepreneurial development paths and livelihood strategies in smallholder irrigation schemes in the Eastern Cape Province of South Africa. The study has outlined five hypothesizes for the basis of concrete scientific research. Initially the study hypothesizes that a smallholder’s socio-cultural contexts such as village level institutions especially village governance as well as household circumstances including age, education and gender compositions of the household membership as well as household income can determine a smallholder’s transformation ability. The second hypothesis was that alternative economic activities especially farming activities such as livestock and crop production as well as off-farm economic opportunities which were open to a household could influence a smallholder’s willingness to change from homestead gardening to food crop production under government irrigation programme. The third hypothesis was on the smallholder’s assessment of available market for the products of his or her food crop irrigation farming which could be an important consideration in his or her willingness to change. The fourth assumption was that entrepreneurial skills are lacking, in particular the ability to search for opportunities and willingness to do something different than the masses and take risks in that process. Finally, the study hypothesized that the government irrigation scheme governance could determine the attractiveness of the scheme and thereby influencing the willingness of a smallholder to participate. Specifically, the legal and regulatory environments are very restrictive and they are not conducive to effective value and job creation in the villages and for the principal crop and livestock enterprises. The study used cross-sectional data collected from both scheme farmers and non-scheme farmers. There were 107 smallholder farmers administered. Cobb-Douglass production and Multiple Regression Models were used. The results indicated 62 percent were male household head and 38 percent were female household head. The majority of the farmers were above middle age for both men and women households head. Specifically, about 80percent were above 51 years of age. Wage employment on the other hand contributed 8percent for both scheme and non-scheme farmers. The majority of the family members were dominated by students and pensioners indicating 27percent of the respondents who were unemployed, among them students were included and pensioners were indicated by 9percent. The overall findings were that there are important differences in behavior regarding the transition from homestead gardening to irrigation farming. Smallholder farmers of Mnquma and Mbhashe municipalities have a great potential in maize, beans, potatoes, pumpkin, butternut production, as well as cattle, sheep, goats, pigs and poultry production. Lastly, the study has highlighted various factors affecting livelihoods sources. Therefore, there is a need for these smallholder farmers to engage consistently with the market to enhance information flow. Extension officers must play a role using the recent extension approach of participatory rural appraisal through discussions with farmers and empower them for marketing problems and solutions. Smallholder farmers must ensure frequent consultation with extension or agricultural advisors for financial and production input support. Government need to strengthen agricultural activities in the rural areas in order to sustain rural livelihoods for rural dwellers. Once the rural economy becomes transformed through agricultural activities then rural dwellers can achieve good standard of living in line with a key macroeconomic objective the South African government. , Thesis (PhD) -- Faculty of Science and Agriculture, 2016
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- Date Issued: 2016-07
An exploration of knowledge sharing as a means of improving municipal governance in selected Limpopo municipalities
- Authors: Dikotla, Maoka Andries https://orcid.org/0000-0002-6699-6782
- Date: 2016-08
- Subjects: Knowledge management , Information services , Organizational learning
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/24750 , vital:63548
- Description: The aim of this study was to underscore the role of knowledge sharing in improving the municipal governance in the local government sector of South Africa. The objectives of the study were to find out the kind of knowledge management programmes which are in place in the municipalities of Limpopo Province; establish the extent to which municipalities in Limpopo encourage knowledge sharing for improvement of municipal governance; determine factors which affect knowledge sharing among employees of municipalities of Limpopo Province, and propose recommendations and strategies on how to optimally share knowledge in Limpopo municipalities. The nature of this study warranted the use of two research paradigms, namely positivist and interpretivist approaches. The study employed an integrated research method which covered both the qualitative and quantitative approach. In collecting data, data instruments were triangulated. In this regard, the researcher mostly used a questionnaire with little employment of interviews and observation. The researcher sampled 438 employees and 21 managers from the selected municipalities. Quantitative data was analysed using IBM Statistical Package for Social Science (SPSS) version 23. Qualitative data was analysed using thematic analysis. The major findings of the study are the following: poor knowledge management programmes in Limpopo municipalities, knowledge sharing among the employees and across the municipalities is not encouraged, knowledge sharing in Limpopo municipalities is affected by both individual and organisational barriers and under-utilisation of information communication technology tools to support knowledge management programmes and practices. Comparatively, the findings of this study to a large extent support what has been recorded in literature. However, the study contradicts a typical mind set of many people that “knowledge is power” and cannot be shared freely. The study recommended to Limpopo municipalities to develop Knowledge sharing strategies that need to be linked to municipal strategic plans; involvement of top management in knowledge management activities; development of knowledge-friendly culture and utilisation of information communication technology tools in support of knowledge sharing. Some recommendations for further study were also provided. Among others, the study recommended that a study on the use of incentive systems as a means of encouraging knowledge sharing be conducted in selected municipalities. This was because studies on the use of incentive systems for motivating knowledge sharing yielded contradictory findings in many organisations. , Thesis (PhD) -- Faculty of Social Sciences and Humanities, 2016
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- Date Issued: 2016-08
A systems thinking approach to e-government strategy formulation for water service delivery in South African local municipalities
- Authors: Osah, Umeoniso Joshua
- Date: 2017
- Subjects: Internet in public administration South Africa , Electronic government information South Africa , Communication in public administration South Africa , Municipal services South Africa , Municipal services Information technology , System theory
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/64471 , vital:28547 , DOI 10.21504/10962/64471
- Description: E-Government deployments by stakeholders within the South African water service sector, provide certain benefits for the sector. While deemed beneficial and of considerable value, e-Government deployments and implementations in the water sector of local governments of South Africa have not always been successful. One important reason for e-Government failures, among several others, is the lack of coherent strategies, informed by key representing stakeholder views, to guide implementation and deployment of e-Government tools. Without strategies, it is highly likely that ICT integration will be conducted haphazardly. As a point of note, more than the deliverable (strategy document) that represents the output of the strategy development process, it serves more purpose to understand the process that results in the strategy. Importantly, understanding the process helps to account for the formed relationships between the various stakeholders that need to buy into the strategy. The research study develops an e-Government strategy formulation framework based on a systems thinking approach, intended to support the strategy formulation process of e-Government strategies – to underpin the effective integration, deployment and sustained use of ICT solutions for water service delivery at the local government level. A systems thinking approach is considered due to its emphasis on the strategy being informed by a holistic assessment. Where there is some knowledge about the processes by which a strategy is formulated – over time ideas may be derived on the types of processes that may produce efficient e-Government strategies. The research is conducted using the Design Science research paradigm. The Design Science paradigm is comprised of two processes – build and evaluate (Hevner et al., 2004). The build process, as related to this research concentrates on the progression through which the theoretical e-Government strategy formulation framework is derived. Weick’s (1989) theorizing approach is ascribed, supporting the design of the theoretical framework. In applying Weick’s theorizing approach, firstly, the lack of knowledge on how e-Government strategies should be formulated in South African local municipalities – is explicated in an intelligible manner. Once the problem is properly articulated, a trial and error selection process is undertaken of existing approaches on strategy formulation – thought to possess the potential to contribute to the development of an e-Government strategy formulation framework, suited to local governments in South Africa. With good reason, 10 (ten) strategy approaches are selected from, e-Government programmes in developed countries, Non-Governmental organizational strategy approaches, and business related strategy formulation approaches. Lastly, as all possible approaches that may contribute to the framework development process cannot be selected, criteria is specified to limit the number of possible selections. Furthermore, in deriving the framework, foundations for systematically dealing with unstructured problems, such as, strategy formulation are consulted. This foundation along with the research goals, informs the development of a template used to comparatively analyse the 10 selected approaches on strategy formulation. This analysis aids in revealing the components of an e-Government strategy formulation process. With the developed framework, the evaluation process of the design science research commences, seeking to determine the utility of the framework (suitability and shortcomings). The framework is applied to the procedural formulation of a strategy for a tentative e-Government project called MobiSAM, which aims to enhance citizen engagement with local government through the use of mobile phones. The strategy formulation application process in the project environment and local government reveals lessons that inform revisions to the framework. The e-Government strategy formulation framework, therefore represents a fundamental tool for e-Government strategy development in local municipalities, and may be customized to fit the requirements of varying local municipalities. , Thesis (PhD) -- Faculty of Commerce, Information Systems, 2017
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- Date Issued: 2017
Assessing the potential role of microorganisms in the production of seedlings for the restoration of Albany Thicket
- Authors: Mpama, Nelisa
- Date: 2017
- Subjects: Vesicular-arbuscular mycorrhizas , Rhizobacteria , Restoration ecology South Africa Albany , Microorganisms
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/64555 , vital:28558
- Description: The role of microorganisms in restoration of the Albany Thicket has not been well documented, although the benefits to plants of these various interactions has been well documented. Microorganisms are chief ecological engineers and assist in resolving environmental problems and act to restore degraded ecosystem function by forming mutual relationships with the roots of the plants. The aim of this study was to assess the potential of microorganisms for the improved biomass production of selected woody and succulent seedlings used in mesic thicket restoration. Three tree species were selected for propagation in this study namely; Mystroxylon aethiopicum Scutia myrtina and Aloe ferox. Soil samples were collected from a degraded and intact thicket site from Bathurst, South Africa. Soils were evaluated for number of arbuscular mycorrhizal (AM) spores, mycorrhizal infectivity potential and nutrient availability both before and after seedling propagation. Pasteurized soil from the degraded site was used in a pot trial. Ten replicates seedling for plant species were planted and subjected to four treatments which included inoculation with AM fungi and the rhizobacterium, Enterobacter sp., alone and in combination; the fourth treatment was an un-inouclated control. Plant growth parameters were recorded at regular intervals where appropriate and seedlings were harvested after 24 weeks for biomass measurements and AM colonisation assessments. Although generally low (< 1 spore per gram) the density of AM fungal spores was significantly higher in soils from the intact site when compared with soils from the degraded site. The mycorrhizal potential of the soils was however not significantly different. Mystroxylon aethiopicum seedling shoot height, canopy diameter and shoot biomass showed a significant increase when inoculated with AM fungi while S. myrtina seedlings showed increased shoot height when inoculated with both AM fungi and Enterobacter sp. Aloe ferox seedlings did not respond to microbial inoculation. The concentration of soil P and Na increased in treatments with Enterobacter sp. alone and in combination with AM fungi. Mystroxylon aethiopicum and S. myrtina seedlings showed a dependency on microbial inoculants indicating the importance of inoculation in the nursery before planting out into the field. Overall AM fungal inoculants applied to seedlings can be used to compensate for nutrient deficiency in soils. Although the Enterobacter isolate used was known to have various plant growth promoting capabilities. It is recommended that other rhizobacterial isolates be investigated. , Thesis (MSc) -- Faculty of Science, Environmental Science, 2017
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- Date Issued: 2017
Comparative fish ecology in three periodically connected rivers in the upper Zambezi and Okavango ecoregions
- Authors: Taylor, Geraldine Claire
- Date: 2017
- Subjects: Fishes Ecology Zambia Zambezi District , Floodplain ecology Zambia Zambezi District , Stable isotopes , Fishes Food Zambia Zambezi District , Fishes Mortality Zambia Zambezi District , Fish populations Zambia Zambezi District , Fishes Growth
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/65055 , vital:28660 , DOI https://doi.org/10.21504/10962/65055
- Description: The Upper Zambezi, Kavango and Kwando rivers are three periodically interlinked floodplain rivers which share the same Upper Zambezian floodplain ichthyofauna. The aim of this thesis was to compare the biology and ecology of the fish communities in these three rivers. The objective was to test the hypothesis that fish community composition and assemblage structure, fish diets, food web structure and trophic dynamics, fish growth rates and total mortality are influenced by the differing flood magnitudes of the three rivers, in support of the flood pulse concept. To understand the abiotic characteristics of each river, water temperature, flood regime, total dissolved inorganic nitrogen concentrations and water quality parameters were measured and compared between rivers. Water temperatures varied seasonally, and seven day moving averages peaked above 30 °C in January, and fell to between 16 and 19 °C in June. The Zambezi River had the largest flood (6.14 m), followed by the Kavango River (3.80 m), while the Kwando River had the smallest flood (0.65 m). Total dissolved inorganic nitrogen concentrations were low in the Kavango and Zambezi Rivers (0.2 - 0.6 mg/l), and slightly higher in the Kwando River (<1 mg/l). Conductivity, total dissolved solids and total dissolved inorganic nitrogen concentrations decreased with the flood (dilution effect). Using biomass catch per unit effort data from experimental gillnets, fish community composition and assemblage structure was described, and differed between rivers in all hydrological seasons. In the Zambezi and Kavango rivers, fish assemblages varied with hydrological season as a result of the homogenising influence of the flood pulse, while in the Kwando River fish assemblages did not differ seasonally as flood pulses were small and often irregular. Differences in community composition were attributed to the abundance of Hydrocynus vittatus, a large bodied open water predator, in the Zambezi and Kavango rivers, and its relative absence in the Kwando River. Based on the results of the community composition, six focus species were chosen that were abundant and representative of the various feeding modes and life history strategies of the fish community. These were the striped robber Brycinus lateralis, sharptooth catfish Clarias gariepinus, blunttooth catfish Clarias ngamensis, African pike Hepsetus cuvieri, silver catfish Schilbe intermedius and purpleface largemouth Serranochromis macrocephalus. Stomach contents analysis was then used to compare the feeding ecology of the six example species between rivers. Clarias gariepinus, C. ngamensis and S. intermedius were piscivorous in the Zambezi and Kavango rivers, and preyed upon more invertebrates in the Kwando River, while Hepsetus cuvieri and S. macrocephalus were piscivorous in all three rivers. Differences in diets were attributed to seasonal prey abundance, with prey fishes abundant during falling and low water when the Zambezi and Kavango rivers were sampled, while invertebrates were abundant during rising and high water when the Kwando River was sampled. Prey mastication by B. lateralis made prey identification difficult. For other predators, the usefulness of stomach contents analysis for dietary descriptions was restricted by the high proportion of empty stomachs. As a result, whole ecosystem stable isotope analysis was used to gain a holistic understanding of the food web structure and fish feeding ecology of the three rivers. The Zambezi and Kavango river food webs were supported by C enriched resources such as C4 and C3 riparian vegetation from the floodplain, while the Kwando River food web was based on C depleted resources such as filamentous algae and aquatic macrophytes. The Zambezi River food web had a restricted nitrogen range, with reduced food chain length and the predators in this river did not occupy such elevated trophic positions compared to in the Kavango and Kwando river food webs. This was attributed to the overfishing of the primary and tertiary consumers in the Zambezi River, a phenomenon known to reduce food chain length. Focussing on predator communities, in the Zambezi and Kavango rivers, H. vittatus isotopic niche width was large and overlapped significantly with most other predators, while in the Kwando River predator niches were more distinct. This supported previously proposed hypotheses by describing H. vittatus as a dominant predator which excludes all other fishes by predation or competition. Despite the dominance of H. vittatus, C. gariepinus occupied the position of top predator in all three rivers, and information on the habitat use, feeding habits and trophic niches of the serranochromine cichlids added understanding of their ecology. Lastly, age was determined using sectioned sagittal otoliths for C. gariepinus, C. ngamensis, S. intermedius and S. macrocephalus and using whole asteriscus otoliths for B. lateralis and H. cuvieri, and growth was modelled using the von Bertalanffy growth equation. Growth performance was high in the Zambezi and Kavango rivers, and lower in the Kwando River, most likely in response to the varying flood magnitudes. Total mortality rates, estimated using Hoenig’s maximum-age based equation, were high in the Zambezi River as a result of the high fishing pressure on this river. Overall floodplain fish ecology in the Zambezi, Kavango and Kwando rivers was influenced by the flood pulse, as was predicted by the flood pulse concept. Periodic and equilibrium life history strategists were found to adapt either to the pulsing environments of the Zambezi and Kavango rivers, or to the more stable environment of the Kwando River, and large bodied, long lived periodic strategists such as C. gariepinus tended to be highly plastic and able to thrive in most conditions. Data also suggested that Zambezi River food web structure and fish mortality rates have been impacted by overfishing, for which more information is needed to conserve and manage this system. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2018
- Full Text:
- Date Issued: 2017
Contributions to the study of nonholonomic Riemannian manifolds
- Authors: Barrett, Dennis Ian
- Date: 2017
- Subjects: Riemannian manifolds , Curvature , Lie groups , Geometry, Riemannian , Tensor fields
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/7554 , vital:21272 , DOI https://doi.org/10.21504/10962/7554
- Description: In this thesis we consider nonholonomic Riemannian manifolds, and in particular, left- invariant nonholonomic Riemannian structures on Lie groups. These structures are closely related to mechanical systems with (positive definite) quadratic Lagrangians and nonholo- nomic constraints linear in velocities. In the first chapter, we review basic concepts of non- holonomic Riemannian geometry, including the left-invariant structures. We also examine the class of left-invariant structures with so-called Cartan-Schouten connections. The second chapter investigates the curvature of nonholonomic Riemannian manifolds and the Schouten and Wagner curvature tensors. The Schouten tensor is canonically associated to every non- holonomic Riemannian structure (in particular, we use it to define isometric invariants for structures on three-dimensional manifolds). By contrast, the Wagner tensor is not generally intrinsic, but can be used to characterise flat structures (i.e., those whose associated parallel transport is path-independent). The third chapter considers equivalence of nonholonomic Rie- mannian manifolds, particularly up to nonholonomic isometry. We also introduce the notion of a nonholonomic Riemannian submanifold, and investigate the conditions under which such a submanifold inherits its geometry from the enveloping space. The latter problem involves the concept of a geodesically invariant distribution, and we show it is also related to the curvature. In the last chapter we specialise to three-dimensional nonholonomic Riemannian manifolds. We consider the equivalence of such structures up to nonholonomic isometry and rescaling, and classify the left-invariant structures on the (three-dimensional) simply connected Lie groups. We also characterise the flat structures in three dimensions, and then classify the flat structures on the simply connected Lie groups. Lastly, we consider three typical examples of (left-invariant) nonholonomic Riemannian structures on three-dimensional Lie groups, two of which arise from problems in classical mechanics (viz., the Chaplygin problem and the Suslov problem). , Thesis (PhD) -- Faculty of Science, Mathematics (Pure and Applied), 2017
- Full Text:
- Date Issued: 2017