A Combined Experimental and Computational Study of Hydridospirophosphorane Ligand Systems Featuring Halogenated Mandelic Acids
- Authors: Maritz, Marius Johann
- Date: 2023-12
- Subjects: Organic compounds -- Synthesis , Heterocyclic compounds , catalysis -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62096 , vital:71911
- Description: The search for new stereoselective catalysts remains important for the isolation of enantiomeric products from racemic mixtures. The need exists for these catalysts to be more efficient, to be more cost effective as well as be stable over time without undergoing changes in molecular structure and selectivity. The purpose of this research project was to experimentally synthesise and characterise asymmetric catalysts for the use in enantioselective synthesis. The catalysts consisted of the main group element phosphorous as central atom, with the phenyl rings of mandelic acid ligands monosubstituted with halogen atoms fluorine, chlorine and bromine in different configurations. Ligand binding resulted in the formation of hydridospirophosphorane structures, from which the molecular properties and binding geometry of these molecules could be explained by the theory of apicophilicity. Characterization was performed by NMR and IR spectroscopy as well as diffraction studies that provided the experimental crystal structures. The structural, energetic and spectroscopy results were compared to the theoretically obtained molecular properties using DFT analysis. Various interand intramolecular interactions that existed between molecules found in crystal packing environments were discussed. Additional properties that were investigated included modelling solvation effects, molecular orbital analysis, Hirshfeld surfaces, orbital and atomic energy and population analysis as well as ESP energy calculations with the optimized crystal structures as input. Molecular overlay comparisons were also performed between the experimental and optimized structures where the effectiveness of various DFT functionals and basis sets could be determined. The method with the best overall cost-to-accuracy ratio was found to be the triple-zeta def2-tzvp basis set with B3LYP functional theory and the addition of Grimme’s dispersion correction. Results indicated differences in crystal packing depending largely on the given halogen atoms present in the substituted phenyl rings, with differences observed in electronegativity and steric effects. One of the crystal systems showed additional interactions with solvent molecules, giving the impression that obtaining crystal void formation was possible. Alterations in the transition state activation energies between the isomers of each molecule were found to be present and supported the theory behind the mechanism of stereochemical induction. The studied compounds were therefore effective in isolating different enantiomeric ligands by means of energy differences between conformers and displayed unique catalytic properties resulting from the phosphorous main group element. The hydridospirophosphoranes conformers responsible for the lowest theoretically calculated activation energy induced crystallization as was seen by diffraction results for all compounds. Even as an intriguing observation, crystallization will largely depend on solubility rather than a specific conformer’s amount in solution. , Thesis (MSc) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Maritz, Marius Johann
- Date: 2023-12
- Subjects: Organic compounds -- Synthesis , Heterocyclic compounds , catalysis -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62096 , vital:71911
- Description: The search for new stereoselective catalysts remains important for the isolation of enantiomeric products from racemic mixtures. The need exists for these catalysts to be more efficient, to be more cost effective as well as be stable over time without undergoing changes in molecular structure and selectivity. The purpose of this research project was to experimentally synthesise and characterise asymmetric catalysts for the use in enantioselective synthesis. The catalysts consisted of the main group element phosphorous as central atom, with the phenyl rings of mandelic acid ligands monosubstituted with halogen atoms fluorine, chlorine and bromine in different configurations. Ligand binding resulted in the formation of hydridospirophosphorane structures, from which the molecular properties and binding geometry of these molecules could be explained by the theory of apicophilicity. Characterization was performed by NMR and IR spectroscopy as well as diffraction studies that provided the experimental crystal structures. The structural, energetic and spectroscopy results were compared to the theoretically obtained molecular properties using DFT analysis. Various interand intramolecular interactions that existed between molecules found in crystal packing environments were discussed. Additional properties that were investigated included modelling solvation effects, molecular orbital analysis, Hirshfeld surfaces, orbital and atomic energy and population analysis as well as ESP energy calculations with the optimized crystal structures as input. Molecular overlay comparisons were also performed between the experimental and optimized structures where the effectiveness of various DFT functionals and basis sets could be determined. The method with the best overall cost-to-accuracy ratio was found to be the triple-zeta def2-tzvp basis set with B3LYP functional theory and the addition of Grimme’s dispersion correction. Results indicated differences in crystal packing depending largely on the given halogen atoms present in the substituted phenyl rings, with differences observed in electronegativity and steric effects. One of the crystal systems showed additional interactions with solvent molecules, giving the impression that obtaining crystal void formation was possible. Alterations in the transition state activation energies between the isomers of each molecule were found to be present and supported the theory behind the mechanism of stereochemical induction. The studied compounds were therefore effective in isolating different enantiomeric ligands by means of energy differences between conformers and displayed unique catalytic properties resulting from the phosphorous main group element. The hydridospirophosphoranes conformers responsible for the lowest theoretically calculated activation energy induced crystallization as was seen by diffraction results for all compounds. Even as an intriguing observation, crystallization will largely depend on solubility rather than a specific conformer’s amount in solution. , Thesis (MSc) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2023
- Full Text:
- Date Issued: 2023-12
Insights into the relative abundance, demographics and behaviour of sea turtles along the east coast of South Africa
- Authors: dos Santos, Natalie Aida
- Date: 2023-12
- Subjects: Sea turtles -- Conservation -- South Africa , Sea turtles -- South Africa , Photogrammetry
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62495 , vital:72778
- Description: Sea turtles are ecologically important species that have endured a history of overexploitation. Combined with their long, complex life cycles and ongoing anthropogenic pressures, they remain conservation-dependent. Conservation efforts worldwide focus on sea turtle nesting beach protection, however, comprehensive management strategies require an understanding of their lives at sea which are often spent in distant waters. This understanding is hindered by the relative challenges of in-water studies. South Africa has also focused research and conservation efforts on nesting adult female loggerheads (Caretta caretta) and leatherbacks (Dermochelys coriacea), largely overlooking the species or age classes remaining at sea. Green turtles (Chelonia mydas), hawksbills (Eretmochelys imbricata) and non-breeding loggerheads are frequently stranded and rehabilitated by aquaria, and observed by recreational divers on reefs, suggesting year-round residency along the country’s entire seaboard. Recent technological advancements in photo-identification methods for sea turtles, underwater photography and internet connectivity allowing even recreational divers to become citizen scientists now place us on the verge of an exciting opportunity to unravel the cryptic in-water ecology of these species. The overall aim of this study was to conduct the first assessment of relative abundance, demographics, distribution, and behaviour of sea turtles on reefs within the iSimangaliso and Aliwal Shoal Marine Protected Areas (MPAs) on the east coast of South Africa. A robust photo-identification database was established from research dives, voluntourism and citizen science contributions over a two-year period. From 1057 sightings in the two MPAs, a total of 227 individual sea turtles were identified constituting three species (green turtles: n = 120; hawksbills: n = 46; loggerheads: n = 61). Their relative abundance was proportional to the overall sizes of the South West Indian Ocean (SWIO) populations (green turtles > hawksbills > loggerheads > leatherbacks). However, sightings per unit effort (SPUE) showed that loggerheads were more prevalent than hawksbills in iSimangaliso, likely due to its proximity to this loggerhead rookery. Reefs supported mixed size aggregations with juvenile to adult-sized green turtles (straight carapace lengths, SCLs of 44.9–99.2 cm), whilst hawksbills were mostly juveniles or subadults (SCL range: 37.4–73.4 cm) and loggerheads were mostly adult-sized (SCL range: 66.9–81 cm). Adult sex ratios were slightly female-biased but not significantly different from 1:1. The longest minimum residence periods recorded for individual subadult green and hawksbill turtles (676 and 675 days respectively) and adult-sized loggerheads (621 days) were suggestive of residency. Resident sea turtle activities were typical; they wereobserved foraging, resting, cleaning and interacting year-round, whilst only loggerheads and leatherbacks were observed in breeding behaviour (e.g., patrolling and mating) just after the seasonal arrival of transient individuals. This study thus reveals that the east coast of South Africa hosts regionally important resident and transient sea turtle aggregations with some of the highest SPUE results recorded for the region. This first attempt at monitoring foraging grounds using a variety of techniques and stakeholder groups can serve as the baseline assessment for future work and the foundation for a long-term in-water monitoring programme, allowing for expansion along the entire coastline. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: dos Santos, Natalie Aida
- Date: 2023-12
- Subjects: Sea turtles -- Conservation -- South Africa , Sea turtles -- South Africa , Photogrammetry
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62495 , vital:72778
- Description: Sea turtles are ecologically important species that have endured a history of overexploitation. Combined with their long, complex life cycles and ongoing anthropogenic pressures, they remain conservation-dependent. Conservation efforts worldwide focus on sea turtle nesting beach protection, however, comprehensive management strategies require an understanding of their lives at sea which are often spent in distant waters. This understanding is hindered by the relative challenges of in-water studies. South Africa has also focused research and conservation efforts on nesting adult female loggerheads (Caretta caretta) and leatherbacks (Dermochelys coriacea), largely overlooking the species or age classes remaining at sea. Green turtles (Chelonia mydas), hawksbills (Eretmochelys imbricata) and non-breeding loggerheads are frequently stranded and rehabilitated by aquaria, and observed by recreational divers on reefs, suggesting year-round residency along the country’s entire seaboard. Recent technological advancements in photo-identification methods for sea turtles, underwater photography and internet connectivity allowing even recreational divers to become citizen scientists now place us on the verge of an exciting opportunity to unravel the cryptic in-water ecology of these species. The overall aim of this study was to conduct the first assessment of relative abundance, demographics, distribution, and behaviour of sea turtles on reefs within the iSimangaliso and Aliwal Shoal Marine Protected Areas (MPAs) on the east coast of South Africa. A robust photo-identification database was established from research dives, voluntourism and citizen science contributions over a two-year period. From 1057 sightings in the two MPAs, a total of 227 individual sea turtles were identified constituting three species (green turtles: n = 120; hawksbills: n = 46; loggerheads: n = 61). Their relative abundance was proportional to the overall sizes of the South West Indian Ocean (SWIO) populations (green turtles > hawksbills > loggerheads > leatherbacks). However, sightings per unit effort (SPUE) showed that loggerheads were more prevalent than hawksbills in iSimangaliso, likely due to its proximity to this loggerhead rookery. Reefs supported mixed size aggregations with juvenile to adult-sized green turtles (straight carapace lengths, SCLs of 44.9–99.2 cm), whilst hawksbills were mostly juveniles or subadults (SCL range: 37.4–73.4 cm) and loggerheads were mostly adult-sized (SCL range: 66.9–81 cm). Adult sex ratios were slightly female-biased but not significantly different from 1:1. The longest minimum residence periods recorded for individual subadult green and hawksbill turtles (676 and 675 days respectively) and adult-sized loggerheads (621 days) were suggestive of residency. Resident sea turtle activities were typical; they wereobserved foraging, resting, cleaning and interacting year-round, whilst only loggerheads and leatherbacks were observed in breeding behaviour (e.g., patrolling and mating) just after the seasonal arrival of transient individuals. This study thus reveals that the east coast of South Africa hosts regionally important resident and transient sea turtle aggregations with some of the highest SPUE results recorded for the region. This first attempt at monitoring foraging grounds using a variety of techniques and stakeholder groups can serve as the baseline assessment for future work and the foundation for a long-term in-water monitoring programme, allowing for expansion along the entire coastline. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-12
A digital transformation framework for municipalities in the Eastern Cape
- Authors: Luke, Lamla Lonwabo Leadley
- Date: 2023-12
- Subjects: Internet in public administration , Information technology -- Political aspects , Electronic government information
- Language: English
- Type: Master's thesis , text
- Identifier: http://hdl.handle.net/10948/62506 , vital:72779
- Description: Digital transformation (DT) integrates technology into all business areas, fundamentally changing how businesses operate and deliver value to their clients. It is also a cultural change that requires organisations to continually challenge the status quo, experiment and get comfortable with change. Smart Municipalities in South Africa have various challenges concerning integrating services and information flow among departments within the municipalities, thus preventing the creation of value for the citizens. The ongoing digital transformation revolutionises urban development and governance, offering opportunities for enhanced citizen services, resource optimisation, and sustainable growth. However, the complexity of implementing smart city initiatives demands a structured approach. Due to urbanisation, municipal management in developing nations must deal with issues like increased energy consumption, pollution, the disposal of toxic wastes, resource depletion, ineffective management of urban infrastructures, ineffective planning processes, overloaded transportation networks, endemic congestion, as well as social inequality and socioeconomic disparity. The extent of digital adoption in the South African province of the Eastern Cape has provided municipalities with a learning opportunity to change into data-driven Smart Municipalities in order to increase productivity, growth, employment, and the need for people with a variety of skills. This study required a review of the literature to examine digital transformation, Smart Municipalities, Smart Municipalities at national and international levels, and Smart Municipality models. The literature review also helped to create a Smart Municipality conceptual model. Data for this study were collected in four Eastern Cape municipalities, namely: DR. AB. Xuma, Enoch Mgijima, Intsika Yethu Local municipalities, and their critical stakeholder Chris Hani District Municipality. The population was all municipal workers, including Municipal Managers, Councillors, Executive Management, ICT officials, Unit Managers, Computer Users and other municipal employees who were using IT to do their job responsibilities within the municipalities. This research study followed a positivistic approach using quantitative methods of analysis. Accordingly, the conceptual model was hypothesised and tested using a questionnaire to collect data and the data were statistically analysed. The study followed a descriptive research designwith a quantitative approach. Various statistical analyses were conducted, including descriptive statistics, reliability and validity metrics of the research instrument, correlation coefficients and Exploratory Factor Analysis (EFA). South Africa has provided municipalities with a learning opportunity to change into data-driven Smart Municipalities to increase productivity, growth, and employment supported by the need for people with a variety of skills. A Value Alignment Smart City Stakeholder (VASCS) model was created in previous research and identified nine dimensions of a smart city, namely Smart Economy, Smart Environment, Smart Governance, Smart Living, Smart Mobility, Smart Organisation, Smart People, Smart Policies and Smart Technology. Due to lack of DT framework and guidelines that guides municipalities on how they can adopt Smart Municipality concept, the objective of this study was to propose and evaluate a Value Alignment Smart Municipality Stakeholder (VASMS) model for municipalities in the Eastern Cape. The nine dimensions were empirically evaluated by stakeholders in four Eastern Cape municipalities. The results depict a change towards the importance of developing a Smart Municipality in the four municipalities, while following appropriate planning, designing, management, operations and governance guidelines. The respondents regarded the smart policy dimension as the most important dimension in the proposed VASMS model. This study further provided practical guidelines for the adoption of smart municipalities in the Eastern Cape Province of South Africa. This proposed VASMS model aims to address the unique challenges faced by municipalities in the Eastern Cape as they embark on their digital transformation journey. It outlines a stepby- step process encompassing strategic planning, technological integration, stakeholder engagement, and governance restructuring. Moreover, it emphasises the importance of fostering a collaborative ecosystem between government agencies, private sector partners, and citizens. By offering this VASMS model, this research contributes to the advancement of Smart Municipality initiatives in the Eastern Cape, ultimately paving the way for more efficient, resilient, and citizen-centric urban environments. , Thesis (MCom) -- Faculty of Science, School of Computing Sciences, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Luke, Lamla Lonwabo Leadley
- Date: 2023-12
- Subjects: Internet in public administration , Information technology -- Political aspects , Electronic government information
- Language: English
- Type: Master's thesis , text
- Identifier: http://hdl.handle.net/10948/62506 , vital:72779
- Description: Digital transformation (DT) integrates technology into all business areas, fundamentally changing how businesses operate and deliver value to their clients. It is also a cultural change that requires organisations to continually challenge the status quo, experiment and get comfortable with change. Smart Municipalities in South Africa have various challenges concerning integrating services and information flow among departments within the municipalities, thus preventing the creation of value for the citizens. The ongoing digital transformation revolutionises urban development and governance, offering opportunities for enhanced citizen services, resource optimisation, and sustainable growth. However, the complexity of implementing smart city initiatives demands a structured approach. Due to urbanisation, municipal management in developing nations must deal with issues like increased energy consumption, pollution, the disposal of toxic wastes, resource depletion, ineffective management of urban infrastructures, ineffective planning processes, overloaded transportation networks, endemic congestion, as well as social inequality and socioeconomic disparity. The extent of digital adoption in the South African province of the Eastern Cape has provided municipalities with a learning opportunity to change into data-driven Smart Municipalities in order to increase productivity, growth, employment, and the need for people with a variety of skills. This study required a review of the literature to examine digital transformation, Smart Municipalities, Smart Municipalities at national and international levels, and Smart Municipality models. The literature review also helped to create a Smart Municipality conceptual model. Data for this study were collected in four Eastern Cape municipalities, namely: DR. AB. Xuma, Enoch Mgijima, Intsika Yethu Local municipalities, and their critical stakeholder Chris Hani District Municipality. The population was all municipal workers, including Municipal Managers, Councillors, Executive Management, ICT officials, Unit Managers, Computer Users and other municipal employees who were using IT to do their job responsibilities within the municipalities. This research study followed a positivistic approach using quantitative methods of analysis. Accordingly, the conceptual model was hypothesised and tested using a questionnaire to collect data and the data were statistically analysed. The study followed a descriptive research designwith a quantitative approach. Various statistical analyses were conducted, including descriptive statistics, reliability and validity metrics of the research instrument, correlation coefficients and Exploratory Factor Analysis (EFA). South Africa has provided municipalities with a learning opportunity to change into data-driven Smart Municipalities to increase productivity, growth, and employment supported by the need for people with a variety of skills. A Value Alignment Smart City Stakeholder (VASCS) model was created in previous research and identified nine dimensions of a smart city, namely Smart Economy, Smart Environment, Smart Governance, Smart Living, Smart Mobility, Smart Organisation, Smart People, Smart Policies and Smart Technology. Due to lack of DT framework and guidelines that guides municipalities on how they can adopt Smart Municipality concept, the objective of this study was to propose and evaluate a Value Alignment Smart Municipality Stakeholder (VASMS) model for municipalities in the Eastern Cape. The nine dimensions were empirically evaluated by stakeholders in four Eastern Cape municipalities. The results depict a change towards the importance of developing a Smart Municipality in the four municipalities, while following appropriate planning, designing, management, operations and governance guidelines. The respondents regarded the smart policy dimension as the most important dimension in the proposed VASMS model. This study further provided practical guidelines for the adoption of smart municipalities in the Eastern Cape Province of South Africa. This proposed VASMS model aims to address the unique challenges faced by municipalities in the Eastern Cape as they embark on their digital transformation journey. It outlines a stepby- step process encompassing strategic planning, technological integration, stakeholder engagement, and governance restructuring. Moreover, it emphasises the importance of fostering a collaborative ecosystem between government agencies, private sector partners, and citizens. By offering this VASMS model, this research contributes to the advancement of Smart Municipality initiatives in the Eastern Cape, ultimately paving the way for more efficient, resilient, and citizen-centric urban environments. , Thesis (MCom) -- Faculty of Science, School of Computing Sciences, 2023
- Full Text:
- Date Issued: 2023-12
Case-based research on the fedup model for self-help housing
- Authors: Qumbisa, Nolwazi
- Date: 2023-12
- Subjects: Community participation , Human settlements , Informal settlements
- Language: English
- Type: doctoral's theses , text
- Identifier: http://hdl.handle.net/10948/62199 , vital:72007
- Description: In South Africa, the government subsidises the building of starter homes to meet the demand for housing for people with lower incomes. However, it is necessary for the state to revise its efforts to meet the demand for housing in the country. Self-help housing is a model that can be used as an alternative to state housing subsidies. The present research study investigates the essential aspects of sustainable self-help housing in the central region of South Africa. The present study aimed to address the central research topic by eliciting responses from participants: How can self-help provision become sustainable in the central region of South Africa? In response to the question, an effective self-help housing support model was developed, the aim of which is to outline how self-help housing projects could be improved. The literature findings demonstrate the potential of this model as a viable alternative to the existing housing delivery mechanism in South Africa. This assertion is supported by a study of self-help housing trajectories and an examination of relevant South African housing policies. However, there has been a lack of emphasis on the simplification of current models to accommodate the needs of implementers, government entities, and beneficiaries of self-help housing initiatives. This study aimed to address the highlighted gaps by utilising a qualitative methodology and drawing upon the data obtained. The data collection techniques included semi-structured interviews, structured observations, and focus-group discussions. A total of 25 semi-structured interviews were conducted with key stakeholders in human settlements, while the focus-group discussions involved 50 participants. A total of 5 focus group discussions were conducted with each group consisting of 10 participants. Moreover, the researcher conducted a document analysis, observations, and questionnaire survey. The data collected were analysed thematically. The results revealed that there are still challenges with implementing self-help housing. Moreover, the results are attributed mainly to a mismatch of the roles and responsibilities and not understanding the Enhanced People’s Housing Process (EPHP) policy. The principal contribution of the thesis is that housing policies, programmes and sector plans must encourage beneficiaries to play an active role. This study found that weak or unclear project vi specifications lead to contractor misunderstandings or discrepancies in housing project implementation, resulting in poor-quality work or delays. The conventional contractor-driven housing-delivery model also has issues like poor construction, corruption and mismanagement, profit-driven contractors, high contractor rates, project delays/incomplete projects, illegal occupation of incomplete projects, riots and disputes, ineffective project specifications, and beneficiary disengagement. In this study, it is demonstrated how a positive social impact on housing could be the outcome of an improved self-help approach. Consequently, the research suggests the adoption of an effective self-help housing support model, which may effectively address the challenges posed by informal settlements while enhancing the execution of self-help housing projects. The model has the potential to make contemporary contributions to the public housing policy model in South Africa. This study contributes to the broader discourse on sustainable housing alternatives, providing insights into the various obstacles, potential advantages, and recommended strategies within the realm of selfhelp housing. The study's qualitative approach facilitated a comprehensive examination of the lived experiences and viewpoints of diverse stakeholders. This yielded valuable insights that can inform policymakers, practitioners, and communities in their efforts to improve the sustainability of self-help housing solutions in the central region of South Africa. , Thesis (PhD) -- Engineering, Built Environment and Technology, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Qumbisa, Nolwazi
- Date: 2023-12
- Subjects: Community participation , Human settlements , Informal settlements
- Language: English
- Type: doctoral's theses , text
- Identifier: http://hdl.handle.net/10948/62199 , vital:72007
- Description: In South Africa, the government subsidises the building of starter homes to meet the demand for housing for people with lower incomes. However, it is necessary for the state to revise its efforts to meet the demand for housing in the country. Self-help housing is a model that can be used as an alternative to state housing subsidies. The present research study investigates the essential aspects of sustainable self-help housing in the central region of South Africa. The present study aimed to address the central research topic by eliciting responses from participants: How can self-help provision become sustainable in the central region of South Africa? In response to the question, an effective self-help housing support model was developed, the aim of which is to outline how self-help housing projects could be improved. The literature findings demonstrate the potential of this model as a viable alternative to the existing housing delivery mechanism in South Africa. This assertion is supported by a study of self-help housing trajectories and an examination of relevant South African housing policies. However, there has been a lack of emphasis on the simplification of current models to accommodate the needs of implementers, government entities, and beneficiaries of self-help housing initiatives. This study aimed to address the highlighted gaps by utilising a qualitative methodology and drawing upon the data obtained. The data collection techniques included semi-structured interviews, structured observations, and focus-group discussions. A total of 25 semi-structured interviews were conducted with key stakeholders in human settlements, while the focus-group discussions involved 50 participants. A total of 5 focus group discussions were conducted with each group consisting of 10 participants. Moreover, the researcher conducted a document analysis, observations, and questionnaire survey. The data collected were analysed thematically. The results revealed that there are still challenges with implementing self-help housing. Moreover, the results are attributed mainly to a mismatch of the roles and responsibilities and not understanding the Enhanced People’s Housing Process (EPHP) policy. The principal contribution of the thesis is that housing policies, programmes and sector plans must encourage beneficiaries to play an active role. This study found that weak or unclear project vi specifications lead to contractor misunderstandings or discrepancies in housing project implementation, resulting in poor-quality work or delays. The conventional contractor-driven housing-delivery model also has issues like poor construction, corruption and mismanagement, profit-driven contractors, high contractor rates, project delays/incomplete projects, illegal occupation of incomplete projects, riots and disputes, ineffective project specifications, and beneficiary disengagement. In this study, it is demonstrated how a positive social impact on housing could be the outcome of an improved self-help approach. Consequently, the research suggests the adoption of an effective self-help housing support model, which may effectively address the challenges posed by informal settlements while enhancing the execution of self-help housing projects. The model has the potential to make contemporary contributions to the public housing policy model in South Africa. This study contributes to the broader discourse on sustainable housing alternatives, providing insights into the various obstacles, potential advantages, and recommended strategies within the realm of selfhelp housing. The study's qualitative approach facilitated a comprehensive examination of the lived experiences and viewpoints of diverse stakeholders. This yielded valuable insights that can inform policymakers, practitioners, and communities in their efforts to improve the sustainability of self-help housing solutions in the central region of South Africa. , Thesis (PhD) -- Engineering, Built Environment and Technology, 2023
- Full Text:
- Date Issued: 2023-12
Statistical analysis of hydrogeochemical data from fractured rock aquifers around Beaufort West, South Africa
- Authors: Berkland, James
- Date: 2023-12
- Subjects: Groundwater -- South Africa -- Beaufort West , Hydrogeology -- South Africa -- Beaufort West , Aquifers -- South Africa -- Beaufort West
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62442 , vital:72736
- Description: Knowledge surrounding the procedures and protocols related to groundwater sampling are currently limited. In particular, the sampling of radioactive elements from fractured rock aquifers is poorly understood and in need of further research. The aim of this study is to provide a comparative insight into groundwater sampling methods used for the sampling of major and minor elements as well as trace elements within fractured rock aquifers in the immediate vicinity of Beaufort West. The influence of sampling source, seasonality, and vertical flows on sample results are observed. Furthermore, the importance of historical datasets is raised. Aims of this study were achieved by making use of historical data from numerous studies that were conducted near the Karoo town of Beaufort West. Potential profitable uranium deposits saw a great influx of research into the geology, topography, climate and hydrogeology. Synthesising data from these historical research papers has provided valuable information regarding the influences of sampling procedures on the results. A total of 695 well data samples were analysed from four studies collected from farms around Beaufort West. The importance of adequately purging a well prior to sampling cannot be stressed enough. There are minimal chemical differences between sampling boreholes and wind pumps, however there was a noticeable difference in the inter-relationships between major chemical elements. Groundwater samplers were found to be contaminated with Zinc and Copper attributed to wind pump fittings. Boreholes were also analysed to observe any changes in depth. Sodium, temperature and uranium had little to no changes with depth due to the homogenous nature of the borehole water. Principal component analysis was conducted on 159 groundwater samples comprised of 13 variables. These samples were reduced to four principal components (PC) which explained a total of 91.09% of the total variance. Factor one explained 61.99% of the total variance and was strongly associated with water-type and lithology while factor two (13.57%) shows the potential relationship between molybdenum and uranium as well as possible copper contamination as a result of wind pump and borehole fittings. Further research should be conducted by carrying out multiple sampling procedures on a selection of controlled wells to determine the best applicable sampling procedures. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Berkland, James
- Date: 2023-12
- Subjects: Groundwater -- South Africa -- Beaufort West , Hydrogeology -- South Africa -- Beaufort West , Aquifers -- South Africa -- Beaufort West
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62442 , vital:72736
- Description: Knowledge surrounding the procedures and protocols related to groundwater sampling are currently limited. In particular, the sampling of radioactive elements from fractured rock aquifers is poorly understood and in need of further research. The aim of this study is to provide a comparative insight into groundwater sampling methods used for the sampling of major and minor elements as well as trace elements within fractured rock aquifers in the immediate vicinity of Beaufort West. The influence of sampling source, seasonality, and vertical flows on sample results are observed. Furthermore, the importance of historical datasets is raised. Aims of this study were achieved by making use of historical data from numerous studies that were conducted near the Karoo town of Beaufort West. Potential profitable uranium deposits saw a great influx of research into the geology, topography, climate and hydrogeology. Synthesising data from these historical research papers has provided valuable information regarding the influences of sampling procedures on the results. A total of 695 well data samples were analysed from four studies collected from farms around Beaufort West. The importance of adequately purging a well prior to sampling cannot be stressed enough. There are minimal chemical differences between sampling boreholes and wind pumps, however there was a noticeable difference in the inter-relationships between major chemical elements. Groundwater samplers were found to be contaminated with Zinc and Copper attributed to wind pump fittings. Boreholes were also analysed to observe any changes in depth. Sodium, temperature and uranium had little to no changes with depth due to the homogenous nature of the borehole water. Principal component analysis was conducted on 159 groundwater samples comprised of 13 variables. These samples were reduced to four principal components (PC) which explained a total of 91.09% of the total variance. Factor one explained 61.99% of the total variance and was strongly associated with water-type and lithology while factor two (13.57%) shows the potential relationship between molybdenum and uranium as well as possible copper contamination as a result of wind pump and borehole fittings. Further research should be conducted by carrying out multiple sampling procedures on a selection of controlled wells to determine the best applicable sampling procedures. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-12
Establishment of a high-content neurodegenerative disease model screening platform
- Authors: Swanepoel, Bresler
- Date: 2023-12
- Subjects: Molecular neurobiology , Nervous system -- Diseases , Nervous system -- Degeneration
- Language: English
- Type: Doctorial theses , text
- Identifier: http://hdl.handle.net/10948/62644 , vital:72906
- Description: The identification of viable therapeutic targets and new treatments for central nervous system disorders, especially neurodegenerative diseases, remain major challenges in the field of drug discovery. Over the past few years there has been a steady decline in the turnaround time of current screening processes to yield viable drugs. Therefore, an increasing need exists for better technologies, protocols, and the screening of larger libraries. High-throughput screening provides the best solution to this problem and has become a key part in the drug discovery and development process. Likewise, high-content analysis has gained popularity over the past few years and is suitable for high-throughput screening. The aim of this study was to establish a comprehensive in vitro neuroprotective screening platform incorporating high throughput screening, using Parkinson’s disease as the neurodegenerative disease of interest. To evaluate the success of this platform, the neuroprotective potential of two mushrooms (Hericium erinaceus and Phlebopus sudanicus), two plants (Lippia javanica and Myrothamnus flabellifolia) and two seaweeds (Eucheuma denticulatum and Kappaphycus alvarezii) were investigated. Aqueous and ethanolic extracts of the selected natural products were evaluated across 21 parameters associated with four hallmarks of neurodegeneration: acquiring senescence, acquiring cell death, neuroinflammation and altered metabolism/cell survival. Based on the effects of these selected natural products on the 21 parameters, their potential mechanisms of action were elucidated. In addition to this, the natural products were scored under each of these therapeutic targets in an attempt to identify the most suitable animal models for future studies. The scoring system indicated that animal models investigating anti-senescence ability would be more suited for extracts of H. erinaceus, P. sudanicus and E. denticulatum whereas studies investigating the prevention of cell death would be more suited for extracts of E. denticulatum, L. javanica and K. alvarezii. Likewise, models based on neuroinflammation would be best suited for extracts of H. erinaceus, E. denticulatum and L. javanica while studies examining altered metabolism/cell survival would be best suited to extracts of H. erinaceus, E. denticulatum, K. alvarezii and M. flabellifolia. Considering the pleiotropic nature of the selected natural products, models that can combine these therapeutic targets could be of great interest. 6-OHDA proved to be capable of inducing favourable effects, in all the parameters investigated, with regard to a neurodegenerative state. However, it is known to have some disadvantages when it comes to pathological features such as the lack of the ability to induce Lewy body formation. Choosing the correct inducer remains a daunting task and no model, whether cell-based or animal-based, exists yet in which all the features of neurodegenerative diseases have been successfully replicated. The limitations of the current models, however, does not mean that they do not produce valuable insights. This is especially true if the mechanism of action for a specific compound or natural product is unknown. Animal models are still indispensable for the validation and interpretation of the results obtained from cell models with particular importance to toxicity. Therefore, this study assessed the best studied extract with the highest overall score for its toxicity using a zebrafish larvae-based model. Assessment of the toxicity of H. erinaceus revealed that both aqueous and ethanolic extracts resulted in death at the highest concentrations. This was supported by the results obtained in the in vitro cytotoxicity screening. In conclusion, this highlighted the importance of using physiologically relevant concentrations and supported the translational value of the current cell-based screening model to animal models and possibly humans. The findings of the present study suggest that a scoring system, which categorizes the different activities of selected natural products into distinct groups, can be a useful tool to improve the translatability of in vitro results to animal models. Furthermore, the current study arguably provides the most comprehensive neuroprotective screening platform in existence. Future research can look at expanding the platform through incorporation of additional parameters based on other hallmarks of neurodegeneration, not covered in this study, including protein folding and aggregation, altered epigenetics and the examination of other neuronal markers such as the involvement of astrocytes, oligodendrocytes, and microglia. In addition to this, future research can make use of more sophisticated cell models such as differentiated, human induced pluripotent stem cells and three-dimensional cultures. , Thesis (PhD) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Swanepoel, Bresler
- Date: 2023-12
- Subjects: Molecular neurobiology , Nervous system -- Diseases , Nervous system -- Degeneration
- Language: English
- Type: Doctorial theses , text
- Identifier: http://hdl.handle.net/10948/62644 , vital:72906
- Description: The identification of viable therapeutic targets and new treatments for central nervous system disorders, especially neurodegenerative diseases, remain major challenges in the field of drug discovery. Over the past few years there has been a steady decline in the turnaround time of current screening processes to yield viable drugs. Therefore, an increasing need exists for better technologies, protocols, and the screening of larger libraries. High-throughput screening provides the best solution to this problem and has become a key part in the drug discovery and development process. Likewise, high-content analysis has gained popularity over the past few years and is suitable for high-throughput screening. The aim of this study was to establish a comprehensive in vitro neuroprotective screening platform incorporating high throughput screening, using Parkinson’s disease as the neurodegenerative disease of interest. To evaluate the success of this platform, the neuroprotective potential of two mushrooms (Hericium erinaceus and Phlebopus sudanicus), two plants (Lippia javanica and Myrothamnus flabellifolia) and two seaweeds (Eucheuma denticulatum and Kappaphycus alvarezii) were investigated. Aqueous and ethanolic extracts of the selected natural products were evaluated across 21 parameters associated with four hallmarks of neurodegeneration: acquiring senescence, acquiring cell death, neuroinflammation and altered metabolism/cell survival. Based on the effects of these selected natural products on the 21 parameters, their potential mechanisms of action were elucidated. In addition to this, the natural products were scored under each of these therapeutic targets in an attempt to identify the most suitable animal models for future studies. The scoring system indicated that animal models investigating anti-senescence ability would be more suited for extracts of H. erinaceus, P. sudanicus and E. denticulatum whereas studies investigating the prevention of cell death would be more suited for extracts of E. denticulatum, L. javanica and K. alvarezii. Likewise, models based on neuroinflammation would be best suited for extracts of H. erinaceus, E. denticulatum and L. javanica while studies examining altered metabolism/cell survival would be best suited to extracts of H. erinaceus, E. denticulatum, K. alvarezii and M. flabellifolia. Considering the pleiotropic nature of the selected natural products, models that can combine these therapeutic targets could be of great interest. 6-OHDA proved to be capable of inducing favourable effects, in all the parameters investigated, with regard to a neurodegenerative state. However, it is known to have some disadvantages when it comes to pathological features such as the lack of the ability to induce Lewy body formation. Choosing the correct inducer remains a daunting task and no model, whether cell-based or animal-based, exists yet in which all the features of neurodegenerative diseases have been successfully replicated. The limitations of the current models, however, does not mean that they do not produce valuable insights. This is especially true if the mechanism of action for a specific compound or natural product is unknown. Animal models are still indispensable for the validation and interpretation of the results obtained from cell models with particular importance to toxicity. Therefore, this study assessed the best studied extract with the highest overall score for its toxicity using a zebrafish larvae-based model. Assessment of the toxicity of H. erinaceus revealed that both aqueous and ethanolic extracts resulted in death at the highest concentrations. This was supported by the results obtained in the in vitro cytotoxicity screening. In conclusion, this highlighted the importance of using physiologically relevant concentrations and supported the translational value of the current cell-based screening model to animal models and possibly humans. The findings of the present study suggest that a scoring system, which categorizes the different activities of selected natural products into distinct groups, can be a useful tool to improve the translatability of in vitro results to animal models. Furthermore, the current study arguably provides the most comprehensive neuroprotective screening platform in existence. Future research can look at expanding the platform through incorporation of additional parameters based on other hallmarks of neurodegeneration, not covered in this study, including protein folding and aggregation, altered epigenetics and the examination of other neuronal markers such as the involvement of astrocytes, oligodendrocytes, and microglia. In addition to this, future research can make use of more sophisticated cell models such as differentiated, human induced pluripotent stem cells and three-dimensional cultures. , Thesis (PhD) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2023
- Full Text:
- Date Issued: 2023-12
Effects of annealing on the structural and optical properties of nanostructured TiO2
- Talla, Assane, Urgessa, Zelalem
- Authors: Talla, Assane , Urgessa, Zelalem
- Date: 2023-12
- Subjects: Titanium dioxide , Nanostructured materials , Nanotubes
- Language: English
- Type: Doctorial theses , text
- Identifier: http://hdl.handle.net/10948/62655 , vital:72907
- Description: In this thesis, the structural, morphological and optical properties of titanium dioxide (TiO2) are investigated. Titanium dioxide (TiO2) nanotubes are prepared by anodic oxidation of titanium foil. The as-anodised samples are thermally annealed at various temperatures in nitrogen, air, oxygen and vacuum. The purpose is to study how the annealing conditions affect the properties of the nanostructures, including the anatase to rutile phase transformation. In all annealing atmospheres, except in vacuum, the dominant phase is found to be anatase when annealing is performed up to 600 oC. Above 700 oC the rutile phase becomes dominant. The anatase phase is stable above 600 oC in vacuum and does not evolve significantly up to 900 oC. The morphologies of the tubes tend to deteriorate with increased annealing temperature, in nitrogen, air and oxygen atmospheres, due to sintering effects. However, the integrity of the nanotubes is maintained up to 900 oC in vacuum. The photoluminescence (PL) spectra suggest mainly the presence of oxygen vacancies and self-trapped excitons, with respective emission bands around 2.5 eV and 2.3 eV. The results show that both the annealing temperature and atmosphere strongly influence the crystalline and optical properties of the TiO2 nanotubes. In addition, the phase transformation from anatase to rutile for samples annealed in an oxygen-rich environment is investigated in detail. Complementary structural information obtained from transmission electron microscopy and Raman analysis for oxygen-annealed samples reveals that the nucleation of the rutile phase starts from the titanium substrate and then propagates along the tubes. The results provide suitable annealing conditions to control the phase content and morphology of anodic TiO2 nanotubes. The PL characteristics of bulk crystalline anatase TiO2, namely virgin and hydrogen-annealed at 600 oC for 1 h, are studied. The low temperature PL spectra at 5.5 K shows near band edge (NBE) emissions with two dominant lines ascribed to shallow donor bound exciton and possibly free to bound recombination. The two main transitions are assisted by optical phononmodes. Temperature-dependent PL measurements performed on these anatase crystals reveal that the donor bound exciton is stable below 90 K. Hydrogen trapped in oxygen vacancies is proposed to be the shallow donor. In addition, two activation processes are involved for the thermal quenching of donor bound excitons. The total activation energy is found to correlate well with the localisation energy of the bound exciton. Site-selective PL spectra obtained from anodic TiO2 tubes reveals that the luminescence of the nanostructures depends on the morphology. The result shows unusual near-band edge emission (NBE) for these structures, which is rarely observed in indirect band gap TiO2. , Thesis (PhD) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Talla, Assane , Urgessa, Zelalem
- Date: 2023-12
- Subjects: Titanium dioxide , Nanostructured materials , Nanotubes
- Language: English
- Type: Doctorial theses , text
- Identifier: http://hdl.handle.net/10948/62655 , vital:72907
- Description: In this thesis, the structural, morphological and optical properties of titanium dioxide (TiO2) are investigated. Titanium dioxide (TiO2) nanotubes are prepared by anodic oxidation of titanium foil. The as-anodised samples are thermally annealed at various temperatures in nitrogen, air, oxygen and vacuum. The purpose is to study how the annealing conditions affect the properties of the nanostructures, including the anatase to rutile phase transformation. In all annealing atmospheres, except in vacuum, the dominant phase is found to be anatase when annealing is performed up to 600 oC. Above 700 oC the rutile phase becomes dominant. The anatase phase is stable above 600 oC in vacuum and does not evolve significantly up to 900 oC. The morphologies of the tubes tend to deteriorate with increased annealing temperature, in nitrogen, air and oxygen atmospheres, due to sintering effects. However, the integrity of the nanotubes is maintained up to 900 oC in vacuum. The photoluminescence (PL) spectra suggest mainly the presence of oxygen vacancies and self-trapped excitons, with respective emission bands around 2.5 eV and 2.3 eV. The results show that both the annealing temperature and atmosphere strongly influence the crystalline and optical properties of the TiO2 nanotubes. In addition, the phase transformation from anatase to rutile for samples annealed in an oxygen-rich environment is investigated in detail. Complementary structural information obtained from transmission electron microscopy and Raman analysis for oxygen-annealed samples reveals that the nucleation of the rutile phase starts from the titanium substrate and then propagates along the tubes. The results provide suitable annealing conditions to control the phase content and morphology of anodic TiO2 nanotubes. The PL characteristics of bulk crystalline anatase TiO2, namely virgin and hydrogen-annealed at 600 oC for 1 h, are studied. The low temperature PL spectra at 5.5 K shows near band edge (NBE) emissions with two dominant lines ascribed to shallow donor bound exciton and possibly free to bound recombination. The two main transitions are assisted by optical phononmodes. Temperature-dependent PL measurements performed on these anatase crystals reveal that the donor bound exciton is stable below 90 K. Hydrogen trapped in oxygen vacancies is proposed to be the shallow donor. In addition, two activation processes are involved for the thermal quenching of donor bound excitons. The total activation energy is found to correlate well with the localisation energy of the bound exciton. Site-selective PL spectra obtained from anodic TiO2 tubes reveals that the luminescence of the nanostructures depends on the morphology. The result shows unusual near-band edge emission (NBE) for these structures, which is rarely observed in indirect band gap TiO2. , Thesis (PhD) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2023
- Full Text:
- Date Issued: 2023-12
Assessing the effects of fish stock management on Cape gannet foraging behaviour in South Africa
- Strydom, Zanri, Grémillet, David, Pichegru, Lorien
- Authors: Strydom, Zanri , Grémillet, David , Pichegru, Lorien
- Date: 2023-12
- Subjects: Gannets -- South Africa , Birds of prey -- Behavior -- South Africa , Fish stock assessment
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/62622 , vital:72887
- Description: Seabirds are one of the most threatened groups of birds under both marine and terrestrial pressures. Among seabirds, the Cape gannet Morus capensis is a southern African endemic species facing several pressures of anthropogenic origin, including competition with industrial fisheries on small pelagic fish stocks. Cape gannets, being a long-lived species that is sensitive to environmental changes, are sentinels of change in oceanic environments granting it important to understand which factors influence their foraging behaviour and breeding outputs. For example, factors like age can result in a loss of physical capabilities which can lead to behavioral compensation and subsequent changes in chick provisioning rates and amounts. With the current fisheries management the fish stocks are continually decreasing, indicating the importance of an updated fine-scale assessment on the spatiotemporal overlap between foraging gannets and fisheries. The first objective of this thesis was to determine the influence of adult Cape gannets’ age and sex on their foraging characteristics and energy expenditure during foraging. I equipped chick-rearing Cape gannets of known age and sex with a 3D accelerometer and GPS device. Foraging effort (trip duration, foraging path and maximum distance to the nest) did not differ between sexes nor with age in Cape gannets. Both sexes rested less on the water with age. Aging females also spent more time in flight than males. The age- and sexual differences in energy expenditure prevalent in our study might reflect niche and/or risk partitioning strategies to ensure adequate provisioning to the chick. The second objective of this thesis was to determine the influence of fisheries catch rates, sardine and anchovy biomass, and adult foraging effort on chick growth rates in Cape gannets, using a long-term dataset collected between 2005 and 2020 on Malgas Island. I equipped chick-rearing adults with a GPS device and I weighed the chicks for between 3 to 6 increments to calculate the average daily mass increment. Of all the variables, foraging trip duration was the main determinant of daily growth rates, with chicks benefitting from parents’ shorter foraging trip durations. Chicks tended to grow slower when fisheries catch of sardine and anchovy were higher, possibly an effect of competition with fisheries. Chicks also grew faster when fish biomass was higher. This long-term monitoring demonstrated the possible effect of food competition between Cape gannets and fisheries, with negative impacts on gannet fitness as determined via chick growth rates. The third objective of this thesis was to determine the influence of both the biomass and fisheries catch rates of sardine and anchovy on Cape gannet foraging effort at a spatial and temporal scale. This was achieved by equipping a total of 668 chick-rearing Cape gannets with a GPS device. With an increase in fisheries catch there was an increase in the birds’ foraging effort. To reduce competition between the gannets and fisheries, the gannets’ core foraging areas seldomly overlapped with the fisheries catch locations, at the cost of the gannets’ increased foraging effort. One method to halt the Cape gannet population decline would be to conserve the fish resources close to the breeding colonies. This would reduce the birds’ foraging whereby increasing their fitness. Safeguarding small pelagic fish to ensure the perseverance of the remaining Benguela seabird populations, would lead to preserving the Benguela marine ecosystem as a whole. My study provided new insight into effects of fish stock management on Cape gannet foraging behaviour in South Africa, and the need for adequate management to ensure population persistence. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Strydom, Zanri , Grémillet, David , Pichegru, Lorien
- Date: 2023-12
- Subjects: Gannets -- South Africa , Birds of prey -- Behavior -- South Africa , Fish stock assessment
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/62622 , vital:72887
- Description: Seabirds are one of the most threatened groups of birds under both marine and terrestrial pressures. Among seabirds, the Cape gannet Morus capensis is a southern African endemic species facing several pressures of anthropogenic origin, including competition with industrial fisheries on small pelagic fish stocks. Cape gannets, being a long-lived species that is sensitive to environmental changes, are sentinels of change in oceanic environments granting it important to understand which factors influence their foraging behaviour and breeding outputs. For example, factors like age can result in a loss of physical capabilities which can lead to behavioral compensation and subsequent changes in chick provisioning rates and amounts. With the current fisheries management the fish stocks are continually decreasing, indicating the importance of an updated fine-scale assessment on the spatiotemporal overlap between foraging gannets and fisheries. The first objective of this thesis was to determine the influence of adult Cape gannets’ age and sex on their foraging characteristics and energy expenditure during foraging. I equipped chick-rearing Cape gannets of known age and sex with a 3D accelerometer and GPS device. Foraging effort (trip duration, foraging path and maximum distance to the nest) did not differ between sexes nor with age in Cape gannets. Both sexes rested less on the water with age. Aging females also spent more time in flight than males. The age- and sexual differences in energy expenditure prevalent in our study might reflect niche and/or risk partitioning strategies to ensure adequate provisioning to the chick. The second objective of this thesis was to determine the influence of fisheries catch rates, sardine and anchovy biomass, and adult foraging effort on chick growth rates in Cape gannets, using a long-term dataset collected between 2005 and 2020 on Malgas Island. I equipped chick-rearing adults with a GPS device and I weighed the chicks for between 3 to 6 increments to calculate the average daily mass increment. Of all the variables, foraging trip duration was the main determinant of daily growth rates, with chicks benefitting from parents’ shorter foraging trip durations. Chicks tended to grow slower when fisheries catch of sardine and anchovy were higher, possibly an effect of competition with fisheries. Chicks also grew faster when fish biomass was higher. This long-term monitoring demonstrated the possible effect of food competition between Cape gannets and fisheries, with negative impacts on gannet fitness as determined via chick growth rates. The third objective of this thesis was to determine the influence of both the biomass and fisheries catch rates of sardine and anchovy on Cape gannet foraging effort at a spatial and temporal scale. This was achieved by equipping a total of 668 chick-rearing Cape gannets with a GPS device. With an increase in fisheries catch there was an increase in the birds’ foraging effort. To reduce competition between the gannets and fisheries, the gannets’ core foraging areas seldomly overlapped with the fisheries catch locations, at the cost of the gannets’ increased foraging effort. One method to halt the Cape gannet population decline would be to conserve the fish resources close to the breeding colonies. This would reduce the birds’ foraging whereby increasing their fitness. Safeguarding small pelagic fish to ensure the perseverance of the remaining Benguela seabird populations, would lead to preserving the Benguela marine ecosystem as a whole. My study provided new insight into effects of fish stock management on Cape gannet foraging behaviour in South Africa, and the need for adequate management to ensure population persistence. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-12
Effects of fire on architecture and composition of canopy shrubs in subtropical dune thicket of the southeastern Cape Floristic Region
- Strydom, Tiaan, Grobler, Adriaan
- Authors: Strydom, Tiaan , Grobler, Adriaan
- Date: 2023-12
- Subjects: Plant ecology -- Research , Plant communities -- South Africa , Browsing (Animal behavior)
- Language: English
- Type: Doctorial theses , text
- Identifier: http://hdl.handle.net/10948/62632 , vital:72899
- Description: Disturbance, such as fire and megaherbivory, is a pervasive phenomenon globally and has different effects on the flora and vegetation of different ecosystems. The Cape Floristic Region (CFR) of South Africa includes the distinctive Subtropical Thicket biome, which occurs as interrupted blocks that are not exposed to fire, but also as mosaics with the fire-prone vegetation of the Fynbos biome, especially on coastal dunes where thicket species are exposed to fire. Subtropical Dune Thicket (hereafter thicket) thus co-occurs with Fynbos, capable of supporting intense fires that can lead to thicket shrub defoliation and mortality. Thicket also experiences disturbance from meso- and megaherbivores that causes defoliation and mortality of shrubs. The aim of this study was to investigate the resilience of thicket shrub species to varying disturbance levels from fire and browsing to understand what drives thicket persistence in a fire-prone landscape. Firstly, I established the architectural traits of thicket species in long unburnt and post-fire contexts and investigated the relationships between these traits and the survival, resprouting ability and persistence of thicket shrubs. In mature thicket, I identified three distinct architectural guilds, namely hedge formers, lateral spreaders, and vertical growers. In post-fire thicket I identified three resprouting architectures, namely weak resprouters, moderate resprouters and strong resprouters. There was no strong relationship between the unburnt and post-fire resprouting architectures. Secondly, I compared thicket species and architectural composition in patches of landscape that experience different levels of fire exposure to assess the potential effect of fire frequency on determining thicket structure. I recognised three thicket vegetation units, each with a distinct structure and each corresponding to the level of fire exposure in the landscape. The first unit, forest-thicket, is exposed to low levels of fire frequency (> 100 years) and harbours forest species, many of which were vertical growers. The second unit, thicket, is exposed to moderate levels of fire frequency (50-100 years) and is dominated by lateral spreaders. The last unit, fynbos-thicket, is exposed to high levels of fire frequency (10-50 years) and here hedge-forming shrubs dominate the canopy cover. Forest-thicket and fynbos-thicket had a diverse set of shrub species with many being restricted to their respective vegetation type, whereas thicket had a lower diversity with no unique shrub species. , Thesis (DPhil) -- Faculty of Science, School of Natural Resource Management, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Strydom, Tiaan , Grobler, Adriaan
- Date: 2023-12
- Subjects: Plant ecology -- Research , Plant communities -- South Africa , Browsing (Animal behavior)
- Language: English
- Type: Doctorial theses , text
- Identifier: http://hdl.handle.net/10948/62632 , vital:72899
- Description: Disturbance, such as fire and megaherbivory, is a pervasive phenomenon globally and has different effects on the flora and vegetation of different ecosystems. The Cape Floristic Region (CFR) of South Africa includes the distinctive Subtropical Thicket biome, which occurs as interrupted blocks that are not exposed to fire, but also as mosaics with the fire-prone vegetation of the Fynbos biome, especially on coastal dunes where thicket species are exposed to fire. Subtropical Dune Thicket (hereafter thicket) thus co-occurs with Fynbos, capable of supporting intense fires that can lead to thicket shrub defoliation and mortality. Thicket also experiences disturbance from meso- and megaherbivores that causes defoliation and mortality of shrubs. The aim of this study was to investigate the resilience of thicket shrub species to varying disturbance levels from fire and browsing to understand what drives thicket persistence in a fire-prone landscape. Firstly, I established the architectural traits of thicket species in long unburnt and post-fire contexts and investigated the relationships between these traits and the survival, resprouting ability and persistence of thicket shrubs. In mature thicket, I identified three distinct architectural guilds, namely hedge formers, lateral spreaders, and vertical growers. In post-fire thicket I identified three resprouting architectures, namely weak resprouters, moderate resprouters and strong resprouters. There was no strong relationship between the unburnt and post-fire resprouting architectures. Secondly, I compared thicket species and architectural composition in patches of landscape that experience different levels of fire exposure to assess the potential effect of fire frequency on determining thicket structure. I recognised three thicket vegetation units, each with a distinct structure and each corresponding to the level of fire exposure in the landscape. The first unit, forest-thicket, is exposed to low levels of fire frequency (> 100 years) and harbours forest species, many of which were vertical growers. The second unit, thicket, is exposed to moderate levels of fire frequency (50-100 years) and is dominated by lateral spreaders. The last unit, fynbos-thicket, is exposed to high levels of fire frequency (10-50 years) and here hedge-forming shrubs dominate the canopy cover. Forest-thicket and fynbos-thicket had a diverse set of shrub species with many being restricted to their respective vegetation type, whereas thicket had a lower diversity with no unique shrub species. , Thesis (DPhil) -- Faculty of Science, School of Natural Resource Management, 2023
- Full Text:
- Date Issued: 2023-12
The use of a novel chemical system towards improving waste tyre pyrolysis and the quality of waste tyre pyrolysis products
- Tsipa, Phuti Cedric, Iwarere, Samuel
- Authors: Tsipa, Phuti Cedric , Iwarere, Samuel
- Date: 2023-12
- Subjects: Tires -- Recycling , Rubber chemicals , Rubber, Reclaimed
- Language: English
- Type: Doctorial theses , text
- Identifier: http://hdl.handle.net/10948/62666 , vital:72912
- Description: Pyrolysis process is one of the most efficient methods in the waste tyre recycling sector at this moment, hence the attention it is receiving. However, this process has some limitations, with the main one being that it is non-conventional and typically energy intensive. In addition, its resultant products have been reported to have significantly poorer properties relative to their virgin counterparts, making it difficult to incorporate them in the mainstream of raw materials. For instance, waste tyre pyrolysis oil typically has poor fuel properties, high sulfur content, high amount of polycyclic aromatic hydrocarbons (PAHs) and strong unpleasant odour; on the other hand, the quality of the recovered carbon black is dependent on the feedstock and the pyrolysis process conditions. Hence the need for further research and development to make the process effective and improve the quality of resultant products. The aim of this research project was to study the impact of pre-pyrolysis treatment of tyre crumbs and post-pyrolysis treatment of the oil using a novel chemical system on the quality/composition of the resultant products. In addition, the study compared the impact of pre- and post-pyrolysis treatments on the optimum pyrolysis time and temperature (energy). The equipment employed in this study included a vertical fixed bed pyrolysis pilot reactor (modified to suit the reaction/experiment) as well as characterization techniques such as fourier transform infrared (FTIR), elemental analysis (carbon, hydrogen, nitrogen and sulfur – CHNS analysis), gas chromatography coupled to mass spectrometer (GCMS), gas chromatography coupled to flame photometric detector (GCFPD), thermo-gravimetric and derivative analysis (TG/DTG isothermal analysis, and proximate analysis) and scanning electron microscope (SEM). The highlight of the findings is that chemically pre-treating tyre crumbs with a mixture of protonic acid and organic solvent before pyrolysis significantly lowered the temperature required to pyrolyze them, from around 400-500 ℃ to 100-115 ℃. This meant that by using the chemical treatment on waste tyres a lot of energy can be saved. In addition, the sulfur content in the oil fraction was reduced from a total of 1.7 wt% to a total of about 0.2 wt%. This also showed that the contaminants in oil were significantly reduced. The oil was condensed into three (3) collectors for fractionation; in collector 2 was about 54 % of the total oil with sulfur content of about 0.015 wt%. The PAHs amounts were also lowered, as literature indicated that PAHs are mostly formed at around 600-700 ℃. It was also found that the oil produced from post-pyrolysis treatment of oil has a petroleum-like smell, whereas the pre-pyrolysis treated oil has a tyre-like pungent odour. Furthermore, the post-pyrolysis treated oil contains higher contents of alkanes and benzene, toluene, xylene (BTX). Findings of this study have a profound potential impact on the waste tyre recycling industry; for example, reduced production energy cost due to lowered temperature required for pyrolysis, improved quality of the products such as lowered sulfur and PAHs content as well as improved quality of the residual char and odour. , Thesis (PhD) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Tsipa, Phuti Cedric , Iwarere, Samuel
- Date: 2023-12
- Subjects: Tires -- Recycling , Rubber chemicals , Rubber, Reclaimed
- Language: English
- Type: Doctorial theses , text
- Identifier: http://hdl.handle.net/10948/62666 , vital:72912
- Description: Pyrolysis process is one of the most efficient methods in the waste tyre recycling sector at this moment, hence the attention it is receiving. However, this process has some limitations, with the main one being that it is non-conventional and typically energy intensive. In addition, its resultant products have been reported to have significantly poorer properties relative to their virgin counterparts, making it difficult to incorporate them in the mainstream of raw materials. For instance, waste tyre pyrolysis oil typically has poor fuel properties, high sulfur content, high amount of polycyclic aromatic hydrocarbons (PAHs) and strong unpleasant odour; on the other hand, the quality of the recovered carbon black is dependent on the feedstock and the pyrolysis process conditions. Hence the need for further research and development to make the process effective and improve the quality of resultant products. The aim of this research project was to study the impact of pre-pyrolysis treatment of tyre crumbs and post-pyrolysis treatment of the oil using a novel chemical system on the quality/composition of the resultant products. In addition, the study compared the impact of pre- and post-pyrolysis treatments on the optimum pyrolysis time and temperature (energy). The equipment employed in this study included a vertical fixed bed pyrolysis pilot reactor (modified to suit the reaction/experiment) as well as characterization techniques such as fourier transform infrared (FTIR), elemental analysis (carbon, hydrogen, nitrogen and sulfur – CHNS analysis), gas chromatography coupled to mass spectrometer (GCMS), gas chromatography coupled to flame photometric detector (GCFPD), thermo-gravimetric and derivative analysis (TG/DTG isothermal analysis, and proximate analysis) and scanning electron microscope (SEM). The highlight of the findings is that chemically pre-treating tyre crumbs with a mixture of protonic acid and organic solvent before pyrolysis significantly lowered the temperature required to pyrolyze them, from around 400-500 ℃ to 100-115 ℃. This meant that by using the chemical treatment on waste tyres a lot of energy can be saved. In addition, the sulfur content in the oil fraction was reduced from a total of 1.7 wt% to a total of about 0.2 wt%. This also showed that the contaminants in oil were significantly reduced. The oil was condensed into three (3) collectors for fractionation; in collector 2 was about 54 % of the total oil with sulfur content of about 0.015 wt%. The PAHs amounts were also lowered, as literature indicated that PAHs are mostly formed at around 600-700 ℃. It was also found that the oil produced from post-pyrolysis treatment of oil has a petroleum-like smell, whereas the pre-pyrolysis treated oil has a tyre-like pungent odour. Furthermore, the post-pyrolysis treated oil contains higher contents of alkanes and benzene, toluene, xylene (BTX). Findings of this study have a profound potential impact on the waste tyre recycling industry; for example, reduced production energy cost due to lowered temperature required for pyrolysis, improved quality of the products such as lowered sulfur and PAHs content as well as improved quality of the residual char and odour. , Thesis (PhD) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2023
- Full Text:
- Date Issued: 2023-12
Functional traits and potential physical drivers of offshore benthic epifauna on the west and south coast of South Africa
- Van Stavel, Jordan, Morris, Tamaryn
- Authors: Van Stavel, Jordan , Morris, Tamaryn
- Date: 2023-12
- Subjects: Marine ecology , Marine biology -- South Africa , Oceanography -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62698 , vital:72931
- Description: Offshore benthic ecosystems (> 200 m depth) are challenging to access and remain poorly studied globally. Epifaunal invertebrates comprise a critical trophic level in benthic ecosystems and can serve as indicators of the overall health and functioning. There is limited knowledge of South Africa’s offshore marine environment and benthic ecosystem functioning due to limitations in funding, resources, and the lack of suitable science-based monitoring tools which are vital for sustainable management into the future. The aim of this research was to improve the understanding of epifaunal functioning as well as their potential physical drivers in 13 South African offshore biogeographic ecotypes. The objectives of this study were threefold: 1) to investigate the functional composition of benthic epifauna from 13 biogeographic ecotypes, 2) to quantify the Functional Diversity (FD) associated with epifaunal traits between the different assemblages (i.e. biogeographic ecotypes), and 3) to evaluate the relationship between physical variables and epifaunal functional traits at the biogeographic ecotype level. Biological trait-based approaches were applied to a subset of 80 benthic epifaunal species collected from 909 offshore stations along the west and south coasts of South Africa. Nine biological traits (associated with life history, morphology and behavioural characteristics exhibited by each species) were classified into 39 modalities and weighted with biomass. Community Weighted Means (CWMs) were used to evaluate the benthic epifaunal functional trait composition of the 13 biogeographic ecotypes. Functional composition across the 13 ecotype assemblages on the west and south coast appeared to be dominated by species with similar trait compositions, such as large, long-lived, surface crawling/burrowing/filter-feeding epifauna with medium to no mobility, however, their percentage of contribution to trait expression (CWMs) was higher on the west coast. Functional diversity indices (alpha and beta) showed higher overall FD for west coast ecotypes, with most ecotypes on the continental shelf (except slopes and canyons) being significantly different (p<0.05) from ecotypes on the south coast. The global RLQ (three-table co-inertia) test did not reveal a significant relationship between biomass and physical variables or between biomass and traits (p>0.05). The fourth-corner method was used to test the significance of individual traitenvironment relationships. The fourth-corner results were similar overall to the RLQ analysis, revealing that three physical variables (temperature, depth, and fluorescence) were significantly correlated to two trait modalities belonging to the feeding mode filter-feeders (FM1) and scavengers (FM5). Scavengers were positively correlated with depth and negatively with temperature, while filter-feeders were positively correlated with fluorescence levels. This indicated that the presence of scavenging epifauna increased with a decrease in temperature and an increase in depth. While a positive significant correlation between filter-feeders and fluorescence suggested their potential tolerance or preference for environmental conditions with high levels of fluorescence. This research was the first such study to explore the functional composition and diversity of benthic epifauna and their relationship with potential physical drivers in offshore west and south coast benthic biogeographic ecotypes of South Africa. The application of new tools to quantify the functional diversity of epifauna as indicators of ecosystem health, and their potential physical drivers. This provided a platform on which to advance our understanding of benthic communities and the roles they play in ecosystem functioning under changing environments. Functional trait-based approaches such as those applied in this study can provide us with vital information on the relationship between biodiversity, ecosystem functioning, and physical drivers. Environmental stressors and changing climate patterns threaten to impact marine ecosystems and their functioning. Benthic epifauna are especially sensitive to changes in their environment and these fluctuations could potentially lead to the loss of certain benthic functionality, altering the thresholds these ecosystems have to response to disturbances. This undermines the stability of these ecosystems which can have ripple effects on the health of these ecosystems and their ability to provide the ecosystem services humans dependent on. Having suitable tools to track current and predict future changes will therefore be vital to inform management and conservation strategies for sustainable ocean utilisation. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Van Stavel, Jordan , Morris, Tamaryn
- Date: 2023-12
- Subjects: Marine ecology , Marine biology -- South Africa , Oceanography -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62698 , vital:72931
- Description: Offshore benthic ecosystems (> 200 m depth) are challenging to access and remain poorly studied globally. Epifaunal invertebrates comprise a critical trophic level in benthic ecosystems and can serve as indicators of the overall health and functioning. There is limited knowledge of South Africa’s offshore marine environment and benthic ecosystem functioning due to limitations in funding, resources, and the lack of suitable science-based monitoring tools which are vital for sustainable management into the future. The aim of this research was to improve the understanding of epifaunal functioning as well as their potential physical drivers in 13 South African offshore biogeographic ecotypes. The objectives of this study were threefold: 1) to investigate the functional composition of benthic epifauna from 13 biogeographic ecotypes, 2) to quantify the Functional Diversity (FD) associated with epifaunal traits between the different assemblages (i.e. biogeographic ecotypes), and 3) to evaluate the relationship between physical variables and epifaunal functional traits at the biogeographic ecotype level. Biological trait-based approaches were applied to a subset of 80 benthic epifaunal species collected from 909 offshore stations along the west and south coasts of South Africa. Nine biological traits (associated with life history, morphology and behavioural characteristics exhibited by each species) were classified into 39 modalities and weighted with biomass. Community Weighted Means (CWMs) were used to evaluate the benthic epifaunal functional trait composition of the 13 biogeographic ecotypes. Functional composition across the 13 ecotype assemblages on the west and south coast appeared to be dominated by species with similar trait compositions, such as large, long-lived, surface crawling/burrowing/filter-feeding epifauna with medium to no mobility, however, their percentage of contribution to trait expression (CWMs) was higher on the west coast. Functional diversity indices (alpha and beta) showed higher overall FD for west coast ecotypes, with most ecotypes on the continental shelf (except slopes and canyons) being significantly different (p<0.05) from ecotypes on the south coast. The global RLQ (three-table co-inertia) test did not reveal a significant relationship between biomass and physical variables or between biomass and traits (p>0.05). The fourth-corner method was used to test the significance of individual traitenvironment relationships. The fourth-corner results were similar overall to the RLQ analysis, revealing that three physical variables (temperature, depth, and fluorescence) were significantly correlated to two trait modalities belonging to the feeding mode filter-feeders (FM1) and scavengers (FM5). Scavengers were positively correlated with depth and negatively with temperature, while filter-feeders were positively correlated with fluorescence levels. This indicated that the presence of scavenging epifauna increased with a decrease in temperature and an increase in depth. While a positive significant correlation between filter-feeders and fluorescence suggested their potential tolerance or preference for environmental conditions with high levels of fluorescence. This research was the first such study to explore the functional composition and diversity of benthic epifauna and their relationship with potential physical drivers in offshore west and south coast benthic biogeographic ecotypes of South Africa. The application of new tools to quantify the functional diversity of epifauna as indicators of ecosystem health, and their potential physical drivers. This provided a platform on which to advance our understanding of benthic communities and the roles they play in ecosystem functioning under changing environments. Functional trait-based approaches such as those applied in this study can provide us with vital information on the relationship between biodiversity, ecosystem functioning, and physical drivers. Environmental stressors and changing climate patterns threaten to impact marine ecosystems and their functioning. Benthic epifauna are especially sensitive to changes in their environment and these fluctuations could potentially lead to the loss of certain benthic functionality, altering the thresholds these ecosystems have to response to disturbances. This undermines the stability of these ecosystems which can have ripple effects on the health of these ecosystems and their ability to provide the ecosystem services humans dependent on. Having suitable tools to track current and predict future changes will therefore be vital to inform management and conservation strategies for sustainable ocean utilisation. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-12
Field mapping and geochemistry of lower Jurassic sediments and volcanics of the upper Karoo supergroup near Ha Mosi, Lesotho mountains
- Authors: Valashiya, Khaya
- Date: 2023-12
- Subjects: Sediments (Geology) -- South Africa -- karoo basin , Geochemistry , Geological mapping
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62687 , vital:72925
- Description: Geological mapping in the Lesotho-Drakensberg Mountains spans over 100 years with du Toit and Stockley being the major contributors to the published maps and to the understanding of emplacement of the Karoo Large Igneous Province (KLIP) in the countries of South Africa and Lesotho. Despite the detailed previous work, there remains limited data on paleoenvironmental changes at the contact between the sedimentary and volcanic sequences of the upper Karoo Supergroup. This study aims to map the lithostratigraphic boundaries, volcano-sedimentary facies and faults near Ha Mosi in southern Lesotho. A total 48 rock samples were collected for petrography, XRF and ICP-MS analyses. The new results were used to characterize the local chemostratigraphy and to propose new regional correlations across Lesotho and South Africa. In this thesis, eight lithostratigraphic units were defined with a total thickness of 550 m. The first two units (Units 1 and 2) comprise massive and bedded sandstones, interpreted as possible floodplain and ephemeral lacustrine deposits; these are ascribed to the upper Stormberg Group. These units are unconformably overlain by locally preserved thin basaltic (Unit 3) flows that are characterised by high Zr/Nb and Zr/Y ratios; and low Ti/Zr and P/Zr ratios similar to the Golden Gate Unit of the Drakensberg Group. The lava flows are overlain by bedded sandstone ascribed to Unit 4 and volcaniclastic breccia ascribed to Units 5 and 6. Unit 6 consists of a monolithic breccia that is composed of angular sandstone clasts similar to those of the underlying Stormberg Group. The monolithic breccia transitions upwards into a massive megaclastic clast-supported volcanic breccia, which consists of angular to sub-rounded basaltic and doleritic boulders. Petrified wood fragments are found within the megaclastic breccia, indicating the presence of vegetation during deposition and enhanced preservation. Unit 6 laterally grades into Unit 5, which is characterised by poorly bedded breccia composed of angular sandstone, mudstone clasts with minor basaltic and doleritic clasts and, breccia intraclasts. The breccia units are often associated with reworked sediments interpreted to be deposited by fluvial systems. The breccia is conformably overlain by basaltic lava flows (Unit 8) characterised by high Ti/Zr and P/Zr ratios and moderate to low Zr/Y and Zr/Nb ratios compared to the Unit 3 lavas and is similar to that of the Sani Pass Unit of the Drakensberg Group. The basaltic sequences in the Ha Mosi studied area preserve both pahoehoe textures and pillow lavas, indicating subaerial and subaqueous volcanism. The studied lithologies are intruded by gabbro and dolerites of the Karoo Dolerite Suite at 183 Ma. This stratigraphy records the transition from sedimentation in the Karoo Basin through to a dominantly volcanic succession, which has importance in terms of the Toarcian extinction at ca. 182 Ma. Mapped faults and associated fractures are orientated predominantly NW-SE with the hanging walls moved maximum 80 m to the south. The different dykes and fault structures possibly relate to the Weddel Triple Junction that developed during the Early Jurassic break up of Gondwana, between 200 and 180 Ma. The mapped lavas show that the magma source was a chemically heterogenous mantle that was subjected to different degrees of partial melting, with the introduction of small-scale chemical heterogeneities. The geodynamic setting is comparable to the Afar Triangle of north-east Africa where active tectonics created a large-scale NW-SE orientated fault system in response to crustal thinning and rifting. In both the Afar and Lesotho, vertical movements created lowlands that allow for the preservation of volcanic breccia and basalts with pillow lavas. These findings show that existing geological models in the Drakensberg-Lesotho Mountains can be improved upon detailed field mapping and geochemistry. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Valashiya, Khaya
- Date: 2023-12
- Subjects: Sediments (Geology) -- South Africa -- karoo basin , Geochemistry , Geological mapping
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62687 , vital:72925
- Description: Geological mapping in the Lesotho-Drakensberg Mountains spans over 100 years with du Toit and Stockley being the major contributors to the published maps and to the understanding of emplacement of the Karoo Large Igneous Province (KLIP) in the countries of South Africa and Lesotho. Despite the detailed previous work, there remains limited data on paleoenvironmental changes at the contact between the sedimentary and volcanic sequences of the upper Karoo Supergroup. This study aims to map the lithostratigraphic boundaries, volcano-sedimentary facies and faults near Ha Mosi in southern Lesotho. A total 48 rock samples were collected for petrography, XRF and ICP-MS analyses. The new results were used to characterize the local chemostratigraphy and to propose new regional correlations across Lesotho and South Africa. In this thesis, eight lithostratigraphic units were defined with a total thickness of 550 m. The first two units (Units 1 and 2) comprise massive and bedded sandstones, interpreted as possible floodplain and ephemeral lacustrine deposits; these are ascribed to the upper Stormberg Group. These units are unconformably overlain by locally preserved thin basaltic (Unit 3) flows that are characterised by high Zr/Nb and Zr/Y ratios; and low Ti/Zr and P/Zr ratios similar to the Golden Gate Unit of the Drakensberg Group. The lava flows are overlain by bedded sandstone ascribed to Unit 4 and volcaniclastic breccia ascribed to Units 5 and 6. Unit 6 consists of a monolithic breccia that is composed of angular sandstone clasts similar to those of the underlying Stormberg Group. The monolithic breccia transitions upwards into a massive megaclastic clast-supported volcanic breccia, which consists of angular to sub-rounded basaltic and doleritic boulders. Petrified wood fragments are found within the megaclastic breccia, indicating the presence of vegetation during deposition and enhanced preservation. Unit 6 laterally grades into Unit 5, which is characterised by poorly bedded breccia composed of angular sandstone, mudstone clasts with minor basaltic and doleritic clasts and, breccia intraclasts. The breccia units are often associated with reworked sediments interpreted to be deposited by fluvial systems. The breccia is conformably overlain by basaltic lava flows (Unit 8) characterised by high Ti/Zr and P/Zr ratios and moderate to low Zr/Y and Zr/Nb ratios compared to the Unit 3 lavas and is similar to that of the Sani Pass Unit of the Drakensberg Group. The basaltic sequences in the Ha Mosi studied area preserve both pahoehoe textures and pillow lavas, indicating subaerial and subaqueous volcanism. The studied lithologies are intruded by gabbro and dolerites of the Karoo Dolerite Suite at 183 Ma. This stratigraphy records the transition from sedimentation in the Karoo Basin through to a dominantly volcanic succession, which has importance in terms of the Toarcian extinction at ca. 182 Ma. Mapped faults and associated fractures are orientated predominantly NW-SE with the hanging walls moved maximum 80 m to the south. The different dykes and fault structures possibly relate to the Weddel Triple Junction that developed during the Early Jurassic break up of Gondwana, between 200 and 180 Ma. The mapped lavas show that the magma source was a chemically heterogenous mantle that was subjected to different degrees of partial melting, with the introduction of small-scale chemical heterogeneities. The geodynamic setting is comparable to the Afar Triangle of north-east Africa where active tectonics created a large-scale NW-SE orientated fault system in response to crustal thinning and rifting. In both the Afar and Lesotho, vertical movements created lowlands that allow for the preservation of volcanic breccia and basalts with pillow lavas. These findings show that existing geological models in the Drakensberg-Lesotho Mountains can be improved upon detailed field mapping and geochemistry. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-12
Finite difference methods for Burgers-Huxley equation and biofilm formation
- Authors: Tijani, Yusuf Olatunji
- Date: 2023-12
- Subjects: Burgers equation , Terrestrial heat flow , Applied mathematics
- Language: English
- Type: Doctorial theses , text
- Identifier: http://hdl.handle.net/10948/62732 , vital:72934
- Description: In this thesis, we constructed some versions of finite difference scheme for the Burgers-Huxley equation and for a set of partial differential equations (PDEs) arising in biofilm formation. The Burgers-Huxley equation serves as a fundamental model that describes the interaction between reaction mechanisms, convection effects, and diffusion transport. It has applications in the study of wave mechanics, population dynamics, physiology, fluid mechanics to list but a few. The study of biofilm formation is becoming increasingly important due to micro-organisms (i.e. bacteria) forming a protected mode from the host defense mechanism which may result in alteration in the host gene transcription and growth rate. Applications can be found useful in the treatment of bacterial infections, contamination of foods and water quality. We designed two nonstandard finite difference and two exponential finite difference schemes for the Burgers-Huxley equation. Numerical experiments with six cases and in three different regimes were studied. We show that the nonstandard scheme preserves the properties of the continuous equation which include positivity and boundedness. The stability region of the explicit exponential scheme was obtained and we outlined the algorithm for the implicit exponential scheme. The performance of the four schemes are compared in regard to absolute error, relative error, L1 and L∞ norms. For a singularly perturbed Burgers-Huxley equation, a novel nonstandard finite difference technique is constructed. It is demonstrated numerically that the NSFD scheme outperforms the classical scheme by comparing maximum pointwise errors and rate of convergence. We then solved the 2D Burgers-Huxley equation using four novel nonstandard finite difference schemes (NSFD1, NSFD2, NSFD3 and NSFD4). The numerical profiles from NSFD1 and NSFD2 exhibit some deviation from the exact profile. Our quest for a better performing scheme led to the modification of NSFD1 using the remainder effect technique. NSFD4 was designed by employing the time splitting approach. All the schemes preserve the properties of the continuous model (positivity and boundedness). The performance of all the schemes are analysed. We construct three nonstandard finite difference schemes for the equations modelling biomass equation and coupled substrate-biomass system of equations respectively. We checked the accuracy of our scheme by the conservation of physical properties (positivity, boundedness, biofilm formation and annihilation) since an analytical solution is not available. We show the instability, lack of conservation of physical properties by the classical scheme. Our proposed scheme shows good performance when compared with other results in the literature. The results here give more insight into the benefits of the nonstandard finite difference approximations. , Thesis (DPhil) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics , 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Tijani, Yusuf Olatunji
- Date: 2023-12
- Subjects: Burgers equation , Terrestrial heat flow , Applied mathematics
- Language: English
- Type: Doctorial theses , text
- Identifier: http://hdl.handle.net/10948/62732 , vital:72934
- Description: In this thesis, we constructed some versions of finite difference scheme for the Burgers-Huxley equation and for a set of partial differential equations (PDEs) arising in biofilm formation. The Burgers-Huxley equation serves as a fundamental model that describes the interaction between reaction mechanisms, convection effects, and diffusion transport. It has applications in the study of wave mechanics, population dynamics, physiology, fluid mechanics to list but a few. The study of biofilm formation is becoming increasingly important due to micro-organisms (i.e. bacteria) forming a protected mode from the host defense mechanism which may result in alteration in the host gene transcription and growth rate. Applications can be found useful in the treatment of bacterial infections, contamination of foods and water quality. We designed two nonstandard finite difference and two exponential finite difference schemes for the Burgers-Huxley equation. Numerical experiments with six cases and in three different regimes were studied. We show that the nonstandard scheme preserves the properties of the continuous equation which include positivity and boundedness. The stability region of the explicit exponential scheme was obtained and we outlined the algorithm for the implicit exponential scheme. The performance of the four schemes are compared in regard to absolute error, relative error, L1 and L∞ norms. For a singularly perturbed Burgers-Huxley equation, a novel nonstandard finite difference technique is constructed. It is demonstrated numerically that the NSFD scheme outperforms the classical scheme by comparing maximum pointwise errors and rate of convergence. We then solved the 2D Burgers-Huxley equation using four novel nonstandard finite difference schemes (NSFD1, NSFD2, NSFD3 and NSFD4). The numerical profiles from NSFD1 and NSFD2 exhibit some deviation from the exact profile. Our quest for a better performing scheme led to the modification of NSFD1 using the remainder effect technique. NSFD4 was designed by employing the time splitting approach. All the schemes preserve the properties of the continuous model (positivity and boundedness). The performance of all the schemes are analysed. We construct three nonstandard finite difference schemes for the equations modelling biomass equation and coupled substrate-biomass system of equations respectively. We checked the accuracy of our scheme by the conservation of physical properties (positivity, boundedness, biofilm formation and annihilation) since an analytical solution is not available. We show the instability, lack of conservation of physical properties by the classical scheme. Our proposed scheme shows good performance when compared with other results in the literature. The results here give more insight into the benefits of the nonstandard finite difference approximations. , Thesis (DPhil) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics , 2023
- Full Text:
- Date Issued: 2023-12
An architecture for feedback-driven learning analytics
- Authors: Winfield, Philip John
- Date: 2023-12
- Subjects: Educational statistics -- Data processing , Education -- Research -- Statistical methods , Teacher-student relationships
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62744 , vital:72935
- Description: Feedback from students provides an opportunity to gain insights into students’ learning behaviour and participation in higher education learning and teaching. Academic staff are expected to constantly review and improve the learning and teaching environment where feedback contributes vital information toward pedagogical decision-making. Reviewing student feedback is essential but time-consuming, making it crucial to explore more effective and efficient ways to analyse and present feedback that encourages intervention and support. The general design science research evaluation pattern guided the construction and evaluation of a Feedback-Driven Architecture (FDA) for Learning Analytics (LA) to address this problem. An FDA implementation using a suitable case demonstrated each component validating the feasibility and effectiveness of the proposed design. The components identified for inclusion in the FDA were integrated within layers of a three-tiered architecture pattern. The data layer incorporates the collection, preparation and storage of learning management system data which includes free-form narrative student feedback. The application layer contains logic to support the analysis of free-form narrative student feedback and extraction of learning analytics. Arrangement and visualisation of information in the presentation layer aim to promote appropriate intervention and support. Evaluation using a case study showed that the FDA provided necessary guidelines for developing an implementation that produced feedbackdriven learning analytics. Data preparation transformed unstructured data into a suitable representation for effective analysis. Cohorts within narrative feedback responses were identified using the k-means clustering algorithm and latent Dirichlet allocation. Logistic regression and support vector machines were applied as predictive models and trained using extracted quantitative markers to predict academic success. , Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Winfield, Philip John
- Date: 2023-12
- Subjects: Educational statistics -- Data processing , Education -- Research -- Statistical methods , Teacher-student relationships
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62744 , vital:72935
- Description: Feedback from students provides an opportunity to gain insights into students’ learning behaviour and participation in higher education learning and teaching. Academic staff are expected to constantly review and improve the learning and teaching environment where feedback contributes vital information toward pedagogical decision-making. Reviewing student feedback is essential but time-consuming, making it crucial to explore more effective and efficient ways to analyse and present feedback that encourages intervention and support. The general design science research evaluation pattern guided the construction and evaluation of a Feedback-Driven Architecture (FDA) for Learning Analytics (LA) to address this problem. An FDA implementation using a suitable case demonstrated each component validating the feasibility and effectiveness of the proposed design. The components identified for inclusion in the FDA were integrated within layers of a three-tiered architecture pattern. The data layer incorporates the collection, preparation and storage of learning management system data which includes free-form narrative student feedback. The application layer contains logic to support the analysis of free-form narrative student feedback and extraction of learning analytics. Arrangement and visualisation of information in the presentation layer aim to promote appropriate intervention and support. Evaluation using a case study showed that the FDA provided necessary guidelines for developing an implementation that produced feedbackdriven learning analytics. Data preparation transformed unstructured data into a suitable representation for effective analysis. Cohorts within narrative feedback responses were identified using the k-means clustering algorithm and latent Dirichlet allocation. Logistic regression and support vector machines were applied as predictive models and trained using extracted quantitative markers to predict academic success. , Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2023
- Full Text:
- Date Issued: 2023-12
Adherence narratives of COVID-19 in KwaNobuhle Township, Eastern Cape
- Authors: Andries, Siyanda
- Date: 2023-12
- Subjects: Coronavirus Disease--Eastern Cape--South Africa , Vaccination--Eastern Cape, South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63243 , vital:73240
- Description: The emergence of COVID-19 triggered a global health crisis that not only took many lives but disrupted economies, strained healthcare systems, and impacted social relations globally. KwaNobuhle township in the Eastern Cape province of South Africa falls under the Nelson Mandela Bay Metropolitan Municipality. This municipality experienced some of South Africa’s highest COVID-19 fatalities, with the lowest levels of testing, active cases and hospitalisation in the country. This study investigates the narratives about COVID-19 prevention measures in KwaNobuhle. Primarily, it seeks to reveal how young and elderly peoples’ perceptions about COVID-19 influenced their compliance with prevention measures such as lockdown, testing and self-admission to hospital when sick. Fifteen residents of KwaNobuhle, who identify as Black people between 18 and 30 years and 50 and 65 years, were recruited as participants in this study. The two groups of study participants were recruited in order to enable an investigation into intergenerational narratives about infectious disease. In this study, Intergenerational narratives encompass stories, beliefs, and cultural traditions that transmit values, historical experiences, and a shared sense of identity, fostering connections between generations. This study provides an historical overview of how communities dealt with previous epidemics in South Africa and analyses how COVID-19 disrupted the lives of people with the preventative measures and changes that were implemented by the government. Social constructivism is a theory that emphasizes the role of social interactions and cultural context in shaping individuals' understanding of the world. Social constructivism theory is employed to frame the investigation of narratives of COVID-19 and is based on qualitative data collected through in-depth telephonic individual interviews. The data reveals that participants’ perceptions and narratives of diseases are shaped and influenced by their experiences and knowledge of the same. The findings confirm that the two different age groups of participants have distinct perspectives of COVID-19. Older participants rely on their past experiences of diseases, while younger participants form their understanding through mainstream and social media. This study further examines the inadequacy of healthcare system preparedness in South Africa to adequately address the onset of infectious diseases. Furthermore, this investigation unveils the way preventive measures against COVID-19 imposed inconvenience upon individuals' daily lives and overall lifestyles. These measures included curfews, a limitation on crowd size in public spaces vii such as markets, and the prohibition of alcohol consumption. Individuals who were reliant on the alcohol industry as their primary source of income were adversely affected. African traditional practices were also impacted, as burial custom alterations resulted. Lastly, the study illuminates that the acceptance and uptake of vaccinations was influenced by vaccine hesitancy, with social media serving as a prominent conduit for the proliferation of conspiracy theories in the context of COVID-19. , Thesis (Ma) -- Faculty of Humanities, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Andries, Siyanda
- Date: 2023-12
- Subjects: Coronavirus Disease--Eastern Cape--South Africa , Vaccination--Eastern Cape, South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63243 , vital:73240
- Description: The emergence of COVID-19 triggered a global health crisis that not only took many lives but disrupted economies, strained healthcare systems, and impacted social relations globally. KwaNobuhle township in the Eastern Cape province of South Africa falls under the Nelson Mandela Bay Metropolitan Municipality. This municipality experienced some of South Africa’s highest COVID-19 fatalities, with the lowest levels of testing, active cases and hospitalisation in the country. This study investigates the narratives about COVID-19 prevention measures in KwaNobuhle. Primarily, it seeks to reveal how young and elderly peoples’ perceptions about COVID-19 influenced their compliance with prevention measures such as lockdown, testing and self-admission to hospital when sick. Fifteen residents of KwaNobuhle, who identify as Black people between 18 and 30 years and 50 and 65 years, were recruited as participants in this study. The two groups of study participants were recruited in order to enable an investigation into intergenerational narratives about infectious disease. In this study, Intergenerational narratives encompass stories, beliefs, and cultural traditions that transmit values, historical experiences, and a shared sense of identity, fostering connections between generations. This study provides an historical overview of how communities dealt with previous epidemics in South Africa and analyses how COVID-19 disrupted the lives of people with the preventative measures and changes that were implemented by the government. Social constructivism is a theory that emphasizes the role of social interactions and cultural context in shaping individuals' understanding of the world. Social constructivism theory is employed to frame the investigation of narratives of COVID-19 and is based on qualitative data collected through in-depth telephonic individual interviews. The data reveals that participants’ perceptions and narratives of diseases are shaped and influenced by their experiences and knowledge of the same. The findings confirm that the two different age groups of participants have distinct perspectives of COVID-19. Older participants rely on their past experiences of diseases, while younger participants form their understanding through mainstream and social media. This study further examines the inadequacy of healthcare system preparedness in South Africa to adequately address the onset of infectious diseases. Furthermore, this investigation unveils the way preventive measures against COVID-19 imposed inconvenience upon individuals' daily lives and overall lifestyles. These measures included curfews, a limitation on crowd size in public spaces vii such as markets, and the prohibition of alcohol consumption. Individuals who were reliant on the alcohol industry as their primary source of income were adversely affected. African traditional practices were also impacted, as burial custom alterations resulted. Lastly, the study illuminates that the acceptance and uptake of vaccinations was influenced by vaccine hesitancy, with social media serving as a prominent conduit for the proliferation of conspiracy theories in the context of COVID-19. , Thesis (Ma) -- Faculty of Humanities, 2023
- Full Text:
- Date Issued: 2023-12
The impact of collaborative writing and scaffolding practices on student writing performance in second language contexts: action research at Midlands State University (MSU)
- Authors: Hlatshwayo, Primrose
- Date: 2023-12
- Subjects: English language -- Context , Writing -- Midlands State University
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63309 , vital:73248
- Description: The mixed methods action research study explored how collaborative writing and scaffolding practices impacted on the writing performance of students writing in groups. It sought to establish whether using the collaborative writing (CW) method would enhance the writing performance of 55 social work Midlands State University first-year students. Socio-cultural theory (SCT) was employed as the theoretical basis for the study as it emphasises learning in socially constructed environments in which interaction among peers and teachers leads to learning and construction of knowledge. Through the examination of student interactions in two collaborative writing activities, an analysis of student perceptions of CW, and an assessment of student collaboratively produced texts, the study found that the different peer and teacher scaffolding practices that were employed in the collaborative writing sessions significantly enhanced the students’ writing performance. Regardless of the challenges identified in CW, for example, misunderstandings and meaningless contributions from some group members, the research findings revealed that the student interactions offered scaffolding to support their writing activities. For example, validation feedback, link to previous knowledge and the use of correctional feedback were the scaffolding practices used. In addition, the students were able to collaboratively produce better texts with improved cohesive linking, mechanics, organisation, development, structure and vocabulary. The study contributed to L2 collaborative writing literature as it identifies the different student scaffolding approaches and offers an insight into the collaborative writing process and how it could support ESL writing development. However, the methodology posed some limitations, for example, the use of a questionnaire instead of interviews and recording student interactions in a journal instead of audio recording and, lastly, the researcher struggled to balance research demands and her normal teaching load. The study recommends the monitoring of students in CW groups, facilitation of peer/teacher motivation, establishment of group norms and formation of small groups with a maximum number of six members. , Thesis (MA) -- Faculty of Humanities, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Hlatshwayo, Primrose
- Date: 2023-12
- Subjects: English language -- Context , Writing -- Midlands State University
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63309 , vital:73248
- Description: The mixed methods action research study explored how collaborative writing and scaffolding practices impacted on the writing performance of students writing in groups. It sought to establish whether using the collaborative writing (CW) method would enhance the writing performance of 55 social work Midlands State University first-year students. Socio-cultural theory (SCT) was employed as the theoretical basis for the study as it emphasises learning in socially constructed environments in which interaction among peers and teachers leads to learning and construction of knowledge. Through the examination of student interactions in two collaborative writing activities, an analysis of student perceptions of CW, and an assessment of student collaboratively produced texts, the study found that the different peer and teacher scaffolding practices that were employed in the collaborative writing sessions significantly enhanced the students’ writing performance. Regardless of the challenges identified in CW, for example, misunderstandings and meaningless contributions from some group members, the research findings revealed that the student interactions offered scaffolding to support their writing activities. For example, validation feedback, link to previous knowledge and the use of correctional feedback were the scaffolding practices used. In addition, the students were able to collaboratively produce better texts with improved cohesive linking, mechanics, organisation, development, structure and vocabulary. The study contributed to L2 collaborative writing literature as it identifies the different student scaffolding approaches and offers an insight into the collaborative writing process and how it could support ESL writing development. However, the methodology posed some limitations, for example, the use of a questionnaire instead of interviews and recording student interactions in a journal instead of audio recording and, lastly, the researcher struggled to balance research demands and her normal teaching load. The study recommends the monitoring of students in CW groups, facilitation of peer/teacher motivation, establishment of group norms and formation of small groups with a maximum number of six members. , Thesis (MA) -- Faculty of Humanities, 2023
- Full Text:
- Date Issued: 2023-12
Assessing the effectiveness of smart solutions on potable water in rural areas within Ngqushwa local municipality
- Authors: Fodo, Portia Noluthando
- Date: 2023-12
- Subjects: Potable water -- tap water , water infrastructure
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63298 , vital:73245
- Description: Providing potable water is a critical reposition towards achieving the Sustainable Development Goal (SDG) 6, to ensure the availability and sustainable management of water and sanitation for all. In addition, the use of smart solutions facilitates towards guaranteeing smart cities aligned with SDG11 which is aimed at making cities and human settlements inclusive, secure, resilient and viable. Access to potable water is a challenging issue in most rural areas as these areas were affected by the Apartheid regime where services were distributed according to the colour of the skin. In rural areas where many black people reside, the challenge of service delivery still exists. Ngqushwa Municipality is faced with several trials in the management of water, including water scarcity, lack of water infrastructure as well as illegal water connections. Despite more than 25 years of democracy, rural dwellers in Ngqushwa Municipality still suffer from a deficiency of access to potable water, which results in other health problems, such as Cholera. This study was aimed at assessing the role of smart solutions in the effective management of potable water in rural areas in Ngqushwa Local Municipality. The objectives to be achieved include identification of the policies that support the implementation of smart solutions in the provision of potable water in Ngqushwa Local Municipality, as well as determining the opportunities and challenges associated with smart solutions in the delivery of potable water. Moreover, identifying the existing difficulties affecting the execution of smart solutions in the delivery of potable water, along with developing recommendations on how smart solutions can effectively be put into operation in rural areas to control water. A qualitative research approach was applied as the chosen research methodology most appropriate to achieving the objectives of the research study. Data was collected using secondary sources and was analysed using thematic content analysis. The study revealed that opportunities available include accurate billing, smart metering and information availability. Furthermore, the obstacles included capacity constraints, cost factors and resistance to change. The investigation recommended, inter alia, that the municipality should accurately train its employees on matters relating to change management and establish effective debt controlling mechanisms to enhance water supervision in rural areas. , Thesis (MA) -- Faculty of Humanities, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Fodo, Portia Noluthando
- Date: 2023-12
- Subjects: Potable water -- tap water , water infrastructure
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63298 , vital:73245
- Description: Providing potable water is a critical reposition towards achieving the Sustainable Development Goal (SDG) 6, to ensure the availability and sustainable management of water and sanitation for all. In addition, the use of smart solutions facilitates towards guaranteeing smart cities aligned with SDG11 which is aimed at making cities and human settlements inclusive, secure, resilient and viable. Access to potable water is a challenging issue in most rural areas as these areas were affected by the Apartheid regime where services were distributed according to the colour of the skin. In rural areas where many black people reside, the challenge of service delivery still exists. Ngqushwa Municipality is faced with several trials in the management of water, including water scarcity, lack of water infrastructure as well as illegal water connections. Despite more than 25 years of democracy, rural dwellers in Ngqushwa Municipality still suffer from a deficiency of access to potable water, which results in other health problems, such as Cholera. This study was aimed at assessing the role of smart solutions in the effective management of potable water in rural areas in Ngqushwa Local Municipality. The objectives to be achieved include identification of the policies that support the implementation of smart solutions in the provision of potable water in Ngqushwa Local Municipality, as well as determining the opportunities and challenges associated with smart solutions in the delivery of potable water. Moreover, identifying the existing difficulties affecting the execution of smart solutions in the delivery of potable water, along with developing recommendations on how smart solutions can effectively be put into operation in rural areas to control water. A qualitative research approach was applied as the chosen research methodology most appropriate to achieving the objectives of the research study. Data was collected using secondary sources and was analysed using thematic content analysis. The study revealed that opportunities available include accurate billing, smart metering and information availability. Furthermore, the obstacles included capacity constraints, cost factors and resistance to change. The investigation recommended, inter alia, that the municipality should accurately train its employees on matters relating to change management and establish effective debt controlling mechanisms to enhance water supervision in rural areas. , Thesis (MA) -- Faculty of Humanities, 2023
- Full Text:
- Date Issued: 2023-12
Assessing the effectiveness of the planning, utilisation and implementation of the electronic human resource management strategy: a case of the department of home affairs in the Eastern Cape
- Authors: Dyan, Margaret Nombuyiselo
- Date: 2023-12
- Subjects: Personnel management , Home Affairs -- Eastern Cape
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63287 , vital:73244
- Description: This study assessed the effectiveness of planning, implementing and utilising the electronic human resource management (e-HRM) strategy within the King William’s Town (KWT) Department of Home Affairs (DHA) in the Eastern Cape Province (EC) of South Africa (SA). E-HRM emerged because of the advent of technology. Many organisations use information technology to optimise the performance of both the employees and the organisation. Thus, this technology has been incorporated into organisations’ human resource functions, taking advantage of the latest technology to deliver an online real-time human resource management (HRM) solution. Therefore, this study sought to assess the e-HRM strategy's effectiveness within the KWT DHA. The technology acceptance model was adopted as a theoretical framework for the study to explain the adoption of the e-HRM strategy. A qualitative research approach using a case study research design was used for this study. Non-probability purposive sampling and convenience sampling were used to identify participants for the study. These participants provided the information needed to answer the research questions. The data was collected using in-depth interviews with the participants. The data was then analysed using thematic analysis following Braun and Clarke’s guidelines (2006). The study results revealed that implementing the e-HRM strategy within KWT DHA proves to be effective and efficient. The strategy’s implementation has been associated with improved performance of the KWT DHA in the Eastern Cape. It also saves time and ensures that HR information is accessed easily. The study also found barriers to the planning, implementation and utilisation of the e-HRM strategy, including a lack of skills and knowledge and resource constraints. The study also found that the current e-HRM policies are not fully functional. The study recommends continuous personnel training regarding the strategy, maximising the use of the e-HRM strategy and addressing the resource challenges. , Thesis (MA) -- Faculty of Humanities, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Dyan, Margaret Nombuyiselo
- Date: 2023-12
- Subjects: Personnel management , Home Affairs -- Eastern Cape
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63287 , vital:73244
- Description: This study assessed the effectiveness of planning, implementing and utilising the electronic human resource management (e-HRM) strategy within the King William’s Town (KWT) Department of Home Affairs (DHA) in the Eastern Cape Province (EC) of South Africa (SA). E-HRM emerged because of the advent of technology. Many organisations use information technology to optimise the performance of both the employees and the organisation. Thus, this technology has been incorporated into organisations’ human resource functions, taking advantage of the latest technology to deliver an online real-time human resource management (HRM) solution. Therefore, this study sought to assess the e-HRM strategy's effectiveness within the KWT DHA. The technology acceptance model was adopted as a theoretical framework for the study to explain the adoption of the e-HRM strategy. A qualitative research approach using a case study research design was used for this study. Non-probability purposive sampling and convenience sampling were used to identify participants for the study. These participants provided the information needed to answer the research questions. The data was collected using in-depth interviews with the participants. The data was then analysed using thematic analysis following Braun and Clarke’s guidelines (2006). The study results revealed that implementing the e-HRM strategy within KWT DHA proves to be effective and efficient. The strategy’s implementation has been associated with improved performance of the KWT DHA in the Eastern Cape. It also saves time and ensures that HR information is accessed easily. The study also found barriers to the planning, implementation and utilisation of the e-HRM strategy, including a lack of skills and knowledge and resource constraints. The study also found that the current e-HRM policies are not fully functional. The study recommends continuous personnel training regarding the strategy, maximising the use of the e-HRM strategy and addressing the resource challenges. , Thesis (MA) -- Faculty of Humanities, 2023
- Full Text:
- Date Issued: 2023-12
A feminist critical discourse analysis of male dominance and violence in Zakes Mda’s the Madonna of excelsior and Chimamanda Ngozi Adichie’s purple hibiscus
- Authors: Ibitoye, Antonia Folasade
- Date: 2023-12
- Subjects: Feminism and education , Feminism and literature
- Language: English
- Type: Doctoral's theses , text
- Identifier: http://hdl.handle.net/10948/63320 , vital:73249
- Description: This study critically explored male dominance and violence in Africa, through the lens of South African author, Zakes Mda, and Nigerian author, Chimamanda Ngozi Adichie, in their novels, The Madonna of Excelsior (2004) and Purple Hibiscus (2003), respectively. Women globally often continue to live with male dominance, and this unequal gender structure has propelled feminists to commence movements to counter all forms of discrimination against women. For the study, excerpts from the two novels were used as data, to investigate male dominance and violence in Africa. To achieve the goals of this research, the study used socialist feminist theory, post-colonial feminist theory, and black feminist theory as the theoretical framework. This combined framework explicates that there is not just one system of oppression at the core of unequal treatment of women by men. Rather, it is a combination of structures related to social class, gender, race, sexuality, culture and society. Feminist critical discourse analysis (FCDA) was employed to analyse the data with the aid of ATLAS.ti software. FCDA was selected as an analytical framework because of its concern for the emancipation of women and social justice with transformation.What prompted the area of concern and the research problem of this study was an awareness of the extensive gender inequality in Nigeria and South Africa, which tends to be rooted in male dominance and violence. As a result, this study contributes to creating awareness of gender inequality, suggesting ways of combating violence against women and female suppression as well as promoting new conceptualisations of masculinity, femininity, and inequality. This research study explored how language use constructed identity, gender, and power relations and how these have reflected male dominance, and violence in Africa in the novels chosen for this study. This study is significant because it did not only analysed the marginalisation and suppression of the female gender but further exposed the strategies that were adopted by women to confront patriarchal oppression and domination as well as the resultant effect on the perpetrators as depicted in the novels for this study. The distinctiveness of this study can be viewed from three different perspectives. Firstly, it is one of the first research works to use FCDA to address the social problems of male dominance and violence. Secondly, it is the first research work which recognises the use of the novel as an essential source of data for FCDA on male dominance and violence. Using the novel as a data source supports the fact that novels are relevant data sources because 5 they often reflect the happenings in society, such as the incidence of gender inequality. Lastly, this project is distinctive because of its ability to combine socialist feminist theory, black feminist theory, post-colonial feminist theory as the theoretical framework and FCDA as the methodological approach. The study is limited to two novels from two African writers because the novels are reflections of the challenges faced by women in Africa and because of the novelists’ unique use of language and the representation of male dominance, violence and female suppression in Africa. The choice to restrict the scope of the study to Africa, selecting Nigeria and South Africa was because, both novels are set in African context and also as a result of the gravity of the identified social and equity issues in Africa. For further research, the study could be extended beyond the African continent to other continents. By so doing, other feminist theories could be used while FCDA could still be used as an analytical framework. Furthermore, a comparative analysis of male dominance and violence between South Africa and Nigeria could also be explored or between Africa and the western world. This study, therefore, explored how language use constructed gender identity and how this reflected male dominance and violence in Africa through the novels, which provided the data for analysis. Following the principles of FCDA, the study sought to create social awareness and to build an understanding of the need not only to resist male dominance and violence but to extend understandings of gender differences with the intention of generating a collective change and transformation in society for gender equality. , Thesis (PhD) -- Faculty of Humanities, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Ibitoye, Antonia Folasade
- Date: 2023-12
- Subjects: Feminism and education , Feminism and literature
- Language: English
- Type: Doctoral's theses , text
- Identifier: http://hdl.handle.net/10948/63320 , vital:73249
- Description: This study critically explored male dominance and violence in Africa, through the lens of South African author, Zakes Mda, and Nigerian author, Chimamanda Ngozi Adichie, in their novels, The Madonna of Excelsior (2004) and Purple Hibiscus (2003), respectively. Women globally often continue to live with male dominance, and this unequal gender structure has propelled feminists to commence movements to counter all forms of discrimination against women. For the study, excerpts from the two novels were used as data, to investigate male dominance and violence in Africa. To achieve the goals of this research, the study used socialist feminist theory, post-colonial feminist theory, and black feminist theory as the theoretical framework. This combined framework explicates that there is not just one system of oppression at the core of unequal treatment of women by men. Rather, it is a combination of structures related to social class, gender, race, sexuality, culture and society. Feminist critical discourse analysis (FCDA) was employed to analyse the data with the aid of ATLAS.ti software. FCDA was selected as an analytical framework because of its concern for the emancipation of women and social justice with transformation.What prompted the area of concern and the research problem of this study was an awareness of the extensive gender inequality in Nigeria and South Africa, which tends to be rooted in male dominance and violence. As a result, this study contributes to creating awareness of gender inequality, suggesting ways of combating violence against women and female suppression as well as promoting new conceptualisations of masculinity, femininity, and inequality. This research study explored how language use constructed identity, gender, and power relations and how these have reflected male dominance, and violence in Africa in the novels chosen for this study. This study is significant because it did not only analysed the marginalisation and suppression of the female gender but further exposed the strategies that were adopted by women to confront patriarchal oppression and domination as well as the resultant effect on the perpetrators as depicted in the novels for this study. The distinctiveness of this study can be viewed from three different perspectives. Firstly, it is one of the first research works to use FCDA to address the social problems of male dominance and violence. Secondly, it is the first research work which recognises the use of the novel as an essential source of data for FCDA on male dominance and violence. Using the novel as a data source supports the fact that novels are relevant data sources because 5 they often reflect the happenings in society, such as the incidence of gender inequality. Lastly, this project is distinctive because of its ability to combine socialist feminist theory, black feminist theory, post-colonial feminist theory as the theoretical framework and FCDA as the methodological approach. The study is limited to two novels from two African writers because the novels are reflections of the challenges faced by women in Africa and because of the novelists’ unique use of language and the representation of male dominance, violence and female suppression in Africa. The choice to restrict the scope of the study to Africa, selecting Nigeria and South Africa was because, both novels are set in African context and also as a result of the gravity of the identified social and equity issues in Africa. For further research, the study could be extended beyond the African continent to other continents. By so doing, other feminist theories could be used while FCDA could still be used as an analytical framework. Furthermore, a comparative analysis of male dominance and violence between South Africa and Nigeria could also be explored or between Africa and the western world. This study, therefore, explored how language use constructed gender identity and how this reflected male dominance and violence in Africa through the novels, which provided the data for analysis. Following the principles of FCDA, the study sought to create social awareness and to build an understanding of the need not only to resist male dominance and violence but to extend understandings of gender differences with the intention of generating a collective change and transformation in society for gender equality. , Thesis (PhD) -- Faculty of Humanities, 2023
- Full Text:
- Date Issued: 2023-12
Evidence of Late Holocene extreme marine wave event (tsunami) deposits along the South African coast and implications for coastal zone management
- Authors: Mfikili, Athi Nkosibonile
- Date: 2023-12
- Subjects: Tsunamis -- South Africa , Coasts -- Risk assessment , Sediments (Geology)
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/62517 , vital:72811
- Description: Although extreme marine wave events such as tsunamis and storm surges have always been part of human existence, their impact on ever-growing coastal population of the world’s coast was highlighted by the recent catastrophic events over the past three decades. Although in situ observations and eyewitness accounts have improved our ability to record and interpret wave inundation by modern extreme marine events, records documenting inundation by pre-historic and historical events are relatively sparse to provide reasonable information on their distribution, magnitude and frequency intervals in most parts of the world. Owing to consequences these natural coastal hazards have on coastal population and infrastructure of the world’s coast, onshore sedimentary deposits preserved in the geological records have been extensively utilized by scientists worldwide to reconstruct the record of pre-historic and historical events and establish the recurrence interval of future events. Although studies investigating inundation of past tsunami has increased worldwide over the past two decades, research on extreme marine inundation has received little attention along the South African coast, despite known inundation by recent events and potential source mechanisms. Therefore, the aim of this study is to investigate sedimentary evidence of past tsunamis and related extreme marine wave events (i.e., storm surges) preserved in the recent geological archive of several coastal environments along the South African coast. The Swartkops, Kabeljous, Kromme and Keurbooms estuaries located in log-spiral bays along the south-east coast and sheltered coastal systems of the Berg Estuary and Verlorenvlei as well as coastal lowlands of the Dwarskersbos on the west coast were selected as the study sites. The sediment cores were collected from these coastal environments and identification of extreme marine wave inundation was based on the recognition of distinct anomalous sand layers. To characterise sediment transport and reconstruct provenance source origin of the deposits, a combination of sedimentological (i.e., grain size distribution), exoscopy (i.e., quartz grain surface microtextures) and micropaleontological (i.e., foraminiferal assemblages) proxies were utilized. Furthermore, age estimation of the deposits was determined using a combination of radiocarbon (14C) and radiometric (137Cs and 210Pb) dating methods.Evidence of coastal flooding by high-energy marine wave events is found preserved in the stratigraphic records of Swartkops and Kabeljous estuaries along the south-east coast and lowlands of Dwarskersbos on the west coast in the form of anomalous sand deposits (layers). The anomalous deposits of Swartkops and Kabeljous estuaries generally consist of gravel-sized shell fragments often with a sharp erosive contact suggesting deposition by a highly energetic marine wave event. Although the preservation varies between cores, a maximum of three anomalous sand depositional layers are preserved in the Swartkops whereas only a single layer in the Kabeljous Estuary with a basal layer of calcrete deposits. 210Pb and 14C dating, constrain the ages of the younger deposits (i.e., the uppermost layer) at Swartkops between 1770-1804 AD and 339-3 cal. BP (1611-1947 cal. AD), respectively. Although these ages span over a wide period, they are interpreted to represent evidence of one of the historical tsunamis generated in the subduction zones of the Indian Ocean e.g., 1762 AD and 1797 AD events generated by 8.8 and 8.0 Mw earthquakes in the Arakan and Sunda Subduction Zones, respectively. Furthermore, the deposits could also represent geological evidence of the 1833 Mentawai events whereas evidence of 1883 Krakatau tsunami is not disregarded, since this event reportedly inundated Algoa Bay. On the other hand, the 14C dating constrain the ages of the second anomalous deposits between 1526-1253 cal. BP (424-697 cal. AD), whereas the older anomalous deposits preserved in the deeper sections of the Swartkops cores as well as the backwater channel of the Kabeljous Estuary are constrained to have been deposited around 4000 cal. BP. Although there is no known locally documented extreme marine wave event during this period, these deposits are interpreted to represent late and mid-Holocene tsunamis associated with mega-thrust subduction zones of the Indian Ocean whereas local submarine landslide generated event are also not disregarded entirely. On the west coast, three anomalous deposits representing extreme marine wave inundation are preserved in the coastal lowlands of the Dwarskersbos. Although the general sedimentary features and thickness vary between the deposits, the first anomalous deposits in the uppermost section of the cores consist of medium sand with scattered shell fragments whereas, the third anomalous deposits in the deeper section of the cores are generally coarser with gravel-sized shell fragments and sharp erosive basal contacts. By contrast, the second anomalous deposits consist of three successive sub-layers of yellow sand with variable sedimentary features and these layers represent successive wave inundation events. Although the sedimentary characteristics of these sub-layers varies, it was noted that the lowermost layers consist of coarser and less well sorted sediments often with basal erosive contact, suggesting that the first wave was more energetic than the two-succeeding waves. Furthermore, calibrated 14C dated shell fragments from the first and second anomalous deposits yielded ‘post-bomb’ ages suggesting deposition after 1950 AD. Given their position within the stratigraphic records, the two deposits are interpreted to represent first geological evidence of the 2008 west coast and 1969 Dwarskersbos events, respectively. On the other hand, the 14C dated shell fragments constrain the deposition of the third anomalous deposits between 315-0 cal. BP (1635-11950 cal. AD) and 358-0 cal. BP (1592-1950 cal. AD), respectively. The third anomalous deposits are interpreted to the 07 April 1620 event, which was described as ‘Two startling thunderclaps’ near Robben Island. Although initially associated to earthquakes, there are no records of an earthquake during this period, therefore, we postulate that the 1620 event could have been a similar event to that of 2008 that inundated the west coast region and/or an unknown event. While it is acknowledged that the absence of reliable source mechanisms poses a great challenge in the reconstruction of extreme marine wave events inundation along the south-east coast, the findings of exoscopy and micropaleontological analyses suggest that the deposits were transported to their depositional environments, although resultant microtextural features and occurrence of individual foraminiferal species and their taphonomical conditions is dependent on coastal setting. The south-east coast deposits consist of highly diverse foraminiferal assemblages, which are dominated by marine and marginal-marine taxa with relatively low abundances of estuarine-brackish species and variable taphonomical conditions. Furthermore, the mechanical-induced features such as percussion marks, fresh surfaces with sharp edges were still preserved on quartz grain surface of the Swartkops deposits, despite dominance by chemical-induced features such as dissolution. By contrast, grain surface microtextural signatures of the Dwarskersbos deposits are dominated by mechanical features such as fresh surfaces and v-percussion marks. Furthermore, the foraminiferal assemblages of the Dwarskersbos deposits consist of exclusively marine and marginal-marine species, suggesting that the sediments were sourced from shallow water environments as well as the adjacent beach. It was further noted that the foraminiferal tests of these deposits consist of higher abundance of corroded and fragmented tests indicating deposition by high-energy conditions. , Thesis (D.Phil) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Mfikili, Athi Nkosibonile
- Date: 2023-12
- Subjects: Tsunamis -- South Africa , Coasts -- Risk assessment , Sediments (Geology)
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/62517 , vital:72811
- Description: Although extreme marine wave events such as tsunamis and storm surges have always been part of human existence, their impact on ever-growing coastal population of the world’s coast was highlighted by the recent catastrophic events over the past three decades. Although in situ observations and eyewitness accounts have improved our ability to record and interpret wave inundation by modern extreme marine events, records documenting inundation by pre-historic and historical events are relatively sparse to provide reasonable information on their distribution, magnitude and frequency intervals in most parts of the world. Owing to consequences these natural coastal hazards have on coastal population and infrastructure of the world’s coast, onshore sedimentary deposits preserved in the geological records have been extensively utilized by scientists worldwide to reconstruct the record of pre-historic and historical events and establish the recurrence interval of future events. Although studies investigating inundation of past tsunami has increased worldwide over the past two decades, research on extreme marine inundation has received little attention along the South African coast, despite known inundation by recent events and potential source mechanisms. Therefore, the aim of this study is to investigate sedimentary evidence of past tsunamis and related extreme marine wave events (i.e., storm surges) preserved in the recent geological archive of several coastal environments along the South African coast. The Swartkops, Kabeljous, Kromme and Keurbooms estuaries located in log-spiral bays along the south-east coast and sheltered coastal systems of the Berg Estuary and Verlorenvlei as well as coastal lowlands of the Dwarskersbos on the west coast were selected as the study sites. The sediment cores were collected from these coastal environments and identification of extreme marine wave inundation was based on the recognition of distinct anomalous sand layers. To characterise sediment transport and reconstruct provenance source origin of the deposits, a combination of sedimentological (i.e., grain size distribution), exoscopy (i.e., quartz grain surface microtextures) and micropaleontological (i.e., foraminiferal assemblages) proxies were utilized. Furthermore, age estimation of the deposits was determined using a combination of radiocarbon (14C) and radiometric (137Cs and 210Pb) dating methods.Evidence of coastal flooding by high-energy marine wave events is found preserved in the stratigraphic records of Swartkops and Kabeljous estuaries along the south-east coast and lowlands of Dwarskersbos on the west coast in the form of anomalous sand deposits (layers). The anomalous deposits of Swartkops and Kabeljous estuaries generally consist of gravel-sized shell fragments often with a sharp erosive contact suggesting deposition by a highly energetic marine wave event. Although the preservation varies between cores, a maximum of three anomalous sand depositional layers are preserved in the Swartkops whereas only a single layer in the Kabeljous Estuary with a basal layer of calcrete deposits. 210Pb and 14C dating, constrain the ages of the younger deposits (i.e., the uppermost layer) at Swartkops between 1770-1804 AD and 339-3 cal. BP (1611-1947 cal. AD), respectively. Although these ages span over a wide period, they are interpreted to represent evidence of one of the historical tsunamis generated in the subduction zones of the Indian Ocean e.g., 1762 AD and 1797 AD events generated by 8.8 and 8.0 Mw earthquakes in the Arakan and Sunda Subduction Zones, respectively. Furthermore, the deposits could also represent geological evidence of the 1833 Mentawai events whereas evidence of 1883 Krakatau tsunami is not disregarded, since this event reportedly inundated Algoa Bay. On the other hand, the 14C dating constrain the ages of the second anomalous deposits between 1526-1253 cal. BP (424-697 cal. AD), whereas the older anomalous deposits preserved in the deeper sections of the Swartkops cores as well as the backwater channel of the Kabeljous Estuary are constrained to have been deposited around 4000 cal. BP. Although there is no known locally documented extreme marine wave event during this period, these deposits are interpreted to represent late and mid-Holocene tsunamis associated with mega-thrust subduction zones of the Indian Ocean whereas local submarine landslide generated event are also not disregarded entirely. On the west coast, three anomalous deposits representing extreme marine wave inundation are preserved in the coastal lowlands of the Dwarskersbos. Although the general sedimentary features and thickness vary between the deposits, the first anomalous deposits in the uppermost section of the cores consist of medium sand with scattered shell fragments whereas, the third anomalous deposits in the deeper section of the cores are generally coarser with gravel-sized shell fragments and sharp erosive basal contacts. By contrast, the second anomalous deposits consist of three successive sub-layers of yellow sand with variable sedimentary features and these layers represent successive wave inundation events. Although the sedimentary characteristics of these sub-layers varies, it was noted that the lowermost layers consist of coarser and less well sorted sediments often with basal erosive contact, suggesting that the first wave was more energetic than the two-succeeding waves. Furthermore, calibrated 14C dated shell fragments from the first and second anomalous deposits yielded ‘post-bomb’ ages suggesting deposition after 1950 AD. Given their position within the stratigraphic records, the two deposits are interpreted to represent first geological evidence of the 2008 west coast and 1969 Dwarskersbos events, respectively. On the other hand, the 14C dated shell fragments constrain the deposition of the third anomalous deposits between 315-0 cal. BP (1635-11950 cal. AD) and 358-0 cal. BP (1592-1950 cal. AD), respectively. The third anomalous deposits are interpreted to the 07 April 1620 event, which was described as ‘Two startling thunderclaps’ near Robben Island. Although initially associated to earthquakes, there are no records of an earthquake during this period, therefore, we postulate that the 1620 event could have been a similar event to that of 2008 that inundated the west coast region and/or an unknown event. While it is acknowledged that the absence of reliable source mechanisms poses a great challenge in the reconstruction of extreme marine wave events inundation along the south-east coast, the findings of exoscopy and micropaleontological analyses suggest that the deposits were transported to their depositional environments, although resultant microtextural features and occurrence of individual foraminiferal species and their taphonomical conditions is dependent on coastal setting. The south-east coast deposits consist of highly diverse foraminiferal assemblages, which are dominated by marine and marginal-marine taxa with relatively low abundances of estuarine-brackish species and variable taphonomical conditions. Furthermore, the mechanical-induced features such as percussion marks, fresh surfaces with sharp edges were still preserved on quartz grain surface of the Swartkops deposits, despite dominance by chemical-induced features such as dissolution. By contrast, grain surface microtextural signatures of the Dwarskersbos deposits are dominated by mechanical features such as fresh surfaces and v-percussion marks. Furthermore, the foraminiferal assemblages of the Dwarskersbos deposits consist of exclusively marine and marginal-marine species, suggesting that the sediments were sourced from shallow water environments as well as the adjacent beach. It was further noted that the foraminiferal tests of these deposits consist of higher abundance of corroded and fragmented tests indicating deposition by high-energy conditions. , Thesis (D.Phil) -- Faculty of Science, School of Environmental Sciences, 2023
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- Date Issued: 2023-12