The on-demand continuous flow generation, separation, and utilization of monosilane gas, a feedstock for solar-grade silicon
- Authors: Mathe, Francis Matota
- Date: 2024-04
- Subjects: Chemistry, Organic , Chemistry , Silicon -- Synthesis
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/64179 , vital:73660
- Description: This research is dedicated to the development of a continuous flow process for the production and utilization of monosilane gas. The utilization of continuous flow techniques was instrumental in addressing the challenges and conditions associated with the handling of monosilane gas. Furthermore, the integration of Process Analytical Technologies (PAT) facilitated in-process monitoring and analysis. Chapter one of this research provides an extensive background and literature review encompassing the purification methods of silicon, the latest advancements in the direct synthesis of alkoxysilanes, current synthesis methods for monosilane, the various applications of monosilane, as well as the utilization of continuous flow technology and process analytical technologies. In chapter two, a detailed account of the experimental procedures employed in this research is presented. Chapter three delves into the results derived from each section of the research. The first section discusses an attempt to upscale the continuous flow synthesis of triethoxysilane, based on previous group research. Process Analytical Technologies (PAT), specifically thermocouples, were utilized in this endeavor. The study revealed temperature inconsistencies along the packed bed reactor, which had a notable impact on the reaction capabilities. The subsequent section explores the continuous flow synthesis of monosilane from triethoxysilane. A Design of Experiment (DoE) approach was employed to identify the optimal reaction conditions and compare the effectiveness of two catalysts. The study determined that Amberlyst-A26 emerged as the superior catalyst, offering stability and reasonable conversions over a 24-hour period. In a residence time of 6 minutes and at a temperature of 55 °C, the maximum triethoxysilane conversion of 100% was achieved. PAT, particularly inline FT-IR, was instrumental in monitoring catalyst activity, while continuous flow gas separation techniques facilitated the separation of monosilane. The research also demonstrated further applications of continuous flow techniques in the synthesis of monosilane from tetraethoxysilane and magnesium silicide. The former aimed to , Thesis (PhD) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 2024
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- Date Issued: 2024-04
The performance of small construction firms in South Africa under the cost leadership strategy
- Authors: Karambakuwa, Ngonidzashe
- Date: 2024-04
- Subjects: Construction industry , Construction industry -- Management , Small business -- Management
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/64577 , vital:73768
- Description: Small construction firms in South Africa have been experiencing poor performance over the years. They have not been cost-efficient, resulting in profitability and viability challenges. These challenges have emanated from the firms’ lack of strategic focus. They have not consciously implemented appropriate strategies to enhance their performance. The cost leadership strategy is therefore a viable option for firms to address their viability challenges because winning contracts depends on submitting the lowest tender bids. This research sought to establish how small construction firms in South Africa could best implement the cost leadership strategy to improve their performance through developing a partial least squares structural equation model (PLS-SEM) to implement identified significant financial, human capital, innovation and technology strategies. The research followed a quantitative research approach. Data was collected through questionnaires, which were distributed to a sample of owners and managers of small construction firms in the provinces of South Africa. The population of the study consisted of small construction firms in grades 2 to 4 on the Construction Industry Development Board’s (CIDB) contractors register. The respondents, who were selected through stratified random sampling, were requested to rate the importance of finance, human capital, innovation and technology strategies in supporting the performance of their firms. A total of 155 usable questionnaires were returned. The data was analysed using the software SPSS Statistics - Version 28. Chi-square tests were used to identify the statistically significant financial, human capital, innovation and technology strategies for the performance of the firms. Furthermore, Mann-Whitney U and Kruskal-Wallis tests were used to determine the statistically significant differences in the respondents’ perceptions of the importance of the strategies due to demographics. Thereafter, a structural model was developed through SEM modelling to determine the relationship between the significant strategies and performance. The results established that increasing the available finance, creating higher incomes compared to costs, increasing contracts per annum and supporting the budget for innovation, significantly contributed to the performance of the construction firms. In addition, prioritising skills development, offering basic salaries with incentives, fostering a strong work ethic, and effective coordination of work were significant strategies. Recognising innovations in technology and human resources cost reductions and carefully promoting innovative ideas through the right support infrastructure were the most significant innovation strategies for performance. It was further established that the acquisition and effective use of computer software and hardware, with the relevant technical knowledge and technical tools, were significant technology strategies for firm performance. The study also established the existence of statistically significant differences in the perception of the importance of innovation and technology strategies due to types of work, and differences in the perception of financial strategies due to age (generation). A PSL-SEM implementation model consisting of statistically significant strategies and demographics was developed and presented graphically. It is recommended that small construction firms should adopt the model to strengthen value chain activities for better performance. The government, the CIDB and other stakeholders should fully support the implementation of the model. , Thesis (DPhil) -- Faculty of Engineering, the Built Environment and Technology, School of Built Environment and Civil Engineering, 2024
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- Date Issued: 2024-04
The promotion of the right to access adequate housing for street children in Kenya
- Authors: Wanjala, Esther Nasimiyu
- Date: 2024-04
- Subjects: Children's rights , Children's act , Street children
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/64358 , vital:73679
- Description: This thesis explores the fundamental right to housing and shelter, recognised at national, regional, and international levels, focusing on its application to street children in Kenya. Despite constitutional provisions, street children in Kenya face exclusion from socio-economic interventions, particularly in the realm of housing and shelter. This exclusion stems from the absence of specific legislation addressing their unique needs. Existing laws, such as the Children Act, 2022 and the Housing Act, 2007 fall short of safeguarding the rights of street children, perpetuating discrimination based on economic status. The research examines international, regional, and national legal frameworks to uncover obstacles hindering street children from enjoying their legally protected human rights, including housing and shelter. Legal instruments such as the Universal Declaration of Human Rights, International Covenant on Economic, Social, and Cultural Rights, International Covenant on Civil and Political Rights, Convention on the Rights of the Child, the African Charter on Human and Peoples Rights, and the African Charter on the Rights and Welfare of a Child and policies like the Sustainable Development Goals 2030, the African Union Agenda 2063, and Agenda 2040 were considered. The research employed qualitative research methodology that included theoretical and non-empirical methods. It used a combination of descriptive, correlative, and limited comparative analysis of the status of street children in the East African Community State Parties of Tanzania, Uganda, and Rwanda, as well as South Africa. Theoretical perspectives, including human rights-based, vulnerability, othering, and capability theories, informed the discussions on improving the status of street children in Kenya. The study employed critical social justice and vulnerability theories to analyse how discrimination and prejudices in society can violate fundamental rights, particularly street children's rights. The findings of the study revealed the inadequate legal and institutional frameworks in promoting street children's rights in Kenya. The study referred to the best practices in the select East African Community State Parties and South Africa that Kenya can emulate to benefit street children and realise the right to shelter and adequate housing. The study recommends legal and policy reviews to protect street children's rights to adequate housing and shelter guided by constitutional and international standards. , Thesis (LLD) -- Faculty of Law, 2024
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- Date Issued: 2024-04
The role of solid waste management in economic development: a case of Nelson Mandela Bay Metropole, South Africa
- Authors: Mngomezulu, Sibongangani Khonelihle
- Date: 2024-04
- Subjects: Integrated solid waste management -- Nelson Mandela Bay Municipality (South Africa) , Refuse and refuse disposal -- Nelson Mandela Bay Municipality (South Africa) , Economic development -- Nelson Mandela Bay Municipality (South Africa)
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/64684 , vital:73861
- Description: The issue of poor Solid Waste Management (SWM) continues to be a challenge in the world, as waste is always generated through daily human activities, and it needs to be properly managed. This study aimed to examine the role of solid waste management in enhancing the urban settlements’ economic development. Guided by the findings and the Circular Economy Model (CEM), the study proposed a waste management framework that can be used to achieve Integrated Solid Waste Management (ISWM) while permitting economic development for the urban poor. The study utilized the mixed methods approach, which involves the collection and the integration of both quantitative and qualitative data to scrutinize the study from multiple points of view to improve accuracy. A mixed methodology with a structured questionnaire was employed. Data was obtained from 256 respondents out of a total of 303 households and one landfill was targeted. The research findings are therefore based on an 84% response rate of the targeted sample size. The study assessed the role that solid waste management can play in economic development using Walmer E, Summerstrand, Gqeberha Central and Arlington Landfill in Nelson Mandela Bay Municipality (NMBM) as the case study areas. The Statistical Package for the Social Sciences (SPSS) was used to generate the descriptive summary statistics for the survey results, and it was also used to analyse the frequency, the correlation, and the factor analysis. The factor analysis was tested using Kaiser-Meyer-Olkin (KMO) and the Initial Eigenvalues, while the data correlation was examined using the Chi-Square Tests and the Symmetric Measures. The narrative thematic method was used for qualitative data, where raw data becomes the actual data presented. This study proves that the current waste management practices in the NMBM area are not sustainable as there is an increasing demand for landfills and the land filled waste has environmental challenges. Therefore, a new waste management framework for tackling these difficulties is proposed with the aid of study findings and CEM. Various theories of economic development and waste management were used and CEM was found more applicable, since it promotes the relationship between waste management systems and economic development. The proposed framework involves four significant factors that were found to positively influence waste to wealth. Those are; social behaviour, education, economic feasibility and governance of Municipal Solid Waste Management (MSWM). The Waste To Wealth (WTW) framework might help to improve solid waste management and shore up the present urban economy. The proposed framework would be applicable not only in the Nelson Mandela Bay Municipality (NMBM) but also in South Africa and in other countries. , Thesis (DPhil) -- Faculty of Engineering, the Built Environment, and Technology, School of Built Environment and Civil Engineering, 2024
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- Date Issued: 2024-04
Using Building Information Modelling to initiate criticality to promote built environment student collaboration at the Nelson Mandela University
- Authors: Basson, Jean-Pierre
- Date: 2024-04
- Subjects: Building information modeling -- South Africa , Architectural design -- Computer simulation , Buildings -- Computer-aided design
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/64470 , vital:73736
- Description: Architectural, engineering, and construction education is fragmented, and there is no collaboration between disciplines during an architectural design project in the design studio. There is a lack of co-creation of knowledge in an interdisciplinary collaborative environment where students use critical reasoning, self-reflection, and critical action, essential skills required to become 21st century global citizens. Therefore, students from the built environment are being prepared contrary to the highly collaborative nature of the industry they are entering upon graduation. The purpose of this study is thus to determine whether adopting a digital interdisciplinary collaborative Building Information Modelling (BIM) environment in which architectural design projects promote criticality in undergraduate exit-level students. A cohort comparison study was used as a method to collect qualitative data. The 2022 cohort used the traditional design process, whereas the 2023 cohort used the BIM process, which supported interdisciplinary collaboration. Both cohorts engaged in a project and student narrative self-reflection essay. Fourteen students from the 2022 and 2023 cohorts participated in the study. The work was analysed using three cycles of coding. The first cycle focused on linguistic acts, followed by the second cycle that looked for evidence of critical reasoning, self-reflection, and action. The third cycle was based on the Habersian validity claims of truth, comprehension, and sincerity. The work of both cohorts was analysed, and findings included the following: relationships; information; emotional reasoning, and digital environment. Based on the research findings, it can be concluded that the BIM process as teaching strategy promotes a higher level of criticality in students than the traditional design process. In conclusion, this research not only contributes to promoting criticality improvement in students but also enriches the existing body of knowledge relative to BIM adoption in AEC education. Moreover, it offers practical guidance for educators to assess and enhance students' critical thinking skills, ultimately advancing the field of interdisciplinary education in the digital era. , Thesis (PhD) -- Faculty of Engineering, the Built Environment, and Technology, School of Built Environment and Civil Engineering, 2024
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- Date Issued: 2024-04
Bioprospectin of medicinal cannabis from Eastern Cape, South Africa
- Authors: Odieka, Anwuli, Endurance
- Date: 2024-02
- Subjects: Organic chemistry
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/11260/9427 , vital:73532
- Description: Cannabis sativa L. (Family Cannabaceae) has continued to attract much interest among natural product scientists in recent time because of its known medicinal values and remarkable chemical diversity. This study reports the investigation of C. sativa cultivated in the Eastern Cape Province of South Africa, with a view to obtaining its chemical fingerprint and isolating compounds from its stem bark for possible biological applications. Fresh and dried leaves, flowers, stem barks and roots of two Cannabis cultivars were obtained under permit NO. PIA-HP-EC-2022-0023. The fresh and dried plant materials were extracted for their essential oils (EOs), using hydro-distillation method on a Clevenger apparatus set at optimum extraction condition. The EOs were characterized by a gas chromatography coupled to a mass spectrometer (GC-MS). The chemical components of the EOs were elucidated based on their retention indices, as well as with reference to literature report. Other portions of the dried leaf, inflorescence and stem bark of each cultivar were extracted with methanol. The methanol extract was profiled for its cannabinoid content using liquid chromatography mass spectrometry (LCMS) based metabolomics approach, with reference to standard cannabinoids (∆9-THC, ∆9-THCA, and CBD). Lastly, the dried stem bark of Cultivar II was investigated for its compounds. The stem bark powder was subjected to sequential extraction at room temperature with n-hexane, dichloromethane, ethyl acetate and methanol. Based on the TLC analysis, the afforded n-hexane and ethyl acetate extracts were further individually fractionated on a repeated column chromatography, using silica gel and Sephadex LH20 as stationary phases. The column fractionation process led to the isolation of seven compounds, E1-E4, A20, A21, and A23. The isolated compounds were characterized by spectroscopic and spectrometric methods on nuclear magnetic resonance (NMR) spectrometer and ultra high-performance liquid chromatography hyphenated to a mass spectrometer, respectively. The results from the study showed that the EOs of the C. sativa cultivars contain majorly sesquiterpenes in their oxygenated and non-oxygenated forms. Caryophyllene (0.6421.4%), caryophyllene oxide (1.27-20.34%), -pinene (0.35-13.21%), D-limonene (0.51-10.99%), humulene (0.37-10.56%), humulene-1,2-epoxide (0.45-5.98%), pinene (0.16-5.22%), nerolidol (0.32-4.99%), -myrcene (0.31-4.23%), -selinene (0.92-2.51%), and trans--bergamotene (0.50-2.70%), were the main terpene constituents of the EOs in both cultivars. Neutral cannabinoids were also detected in both cultivars with cannabidiol found in significant amount up to 85.03% in the fresh stem oil (LSO) of Cultivar I (Lifter). LC-MS fingerprints revealed that Cultivar I had the highest accumulation of cannabinoids with CBDA having the highest amount (88.65%) in the stembark and CBD at about 23% in the leaves. The inflorescence (flower) contained 51.55% of CBDA. Cultivar II had the least number of cannabinoids but contains the highest amount of ∆9-THCA (94.8%) in the leaf sample. Cultivar II showed ∆9-THCA and ∆9-THC dominant profiles with less than 2% of ∆8-THC. ∆9-THC, ∆8- THC were the only neutral cannabinoids detected in Cultivar II while CBD, ∆9-THC, and ∆8- THC were found in significant amounts in Cultivar I. The compounds isolated from the stem bark of Cultivar II were elucidated as five triterpenoids: Sativalenic acid ethyl ester (E1), Phyllanthone (E2), Friedelin (E3), Sativalonone (A20) and Sativaol (A23); an alkaloid, Sativacherine (E4); and a fatty acid ester, Ethyl stearate (A21). Four of these compounds are newly described, while all the compounds are reported for the first time from the Eastern Cape Cultivar (Cherrywine) of C. sativa stem. , Thesis (PHD) -- Faculty of Natural Sciences, 2024
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- Date Issued: 2024-02
Systematic effects and mitigation strategies in observations of cosmic re-ionisation with the Hydrogen Epoch of Reionization Array
- Authors: Charles, Ntsikelelo
- Date: 2024
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/432605 , vital:72886 , DOI 10.21504/10962/432605
- Description: The 21 cm transition from neutral Hydrogen promises to be the best observational probe of the Epoch of Reionisation (EoR). It has driven the construction of the new generation of lowfrequency radio interferometric arrays, including the Hydrogen Epoch of Reionization Array (HERA). The main difficulty in measuring the 21 cm signal is the presence of bright foregrounds that require very accurate interferometric calibration. However, the non-smooth instrumental response of the antenna as a result of mutual coupling complicates the calibration process by introducing non-smooth calibration errors. Additionally, incomplete sky models are typically used in calibration due to the limited depth and resolution of current source catalogues. Combined with the instrumental response, the use of incomplete sky models during calibration can result in non-smooth calibration errors. These, overall, impart spectral structure on smooth foregrounds, leading to foreground power leakage into the EoR window. In this thesis we explored the use of fringe rate filters (Parsons et al., 2016) as a mean to mitigate calibration errors resulting from the effects of mutual coupling and the use of an incomplete sky model during calibration. We found that the use of a simple notch filter mitigates calibration errors reducing the foreground power leakage into the EoR window by a factor of ∼ 102. Thyagarajan et al. (2018) proposed the use of closure phase quantities as a means to detect the 21 cm signal, which has the advantage of being independent (to first order) from calibration errors and, therefore, bypasses the need for accurate calibration. In this thesis, we explore the impact of primary beam patterns affected by mutual coupling on the closure phase. We found that primary beams affected by mutual coupling lead to a leakage of foreground power into the EoR window, which can be up to ∼ 104 times and is mainly caused by the unsmooth spectral structure primary of primary beam sidelobes affected by mutual coupling. This power leakage was confined to k < 0.3 pseudo h Mpc−1. Lastly, we also proposed and demonstrated an analysis technique that can be used to derive a flux scale correction in post-calibrated HERA data. We found that after applying flux scale correction to calibrated HERA data, the bandpass error reduces significantly, with an improvement of 6%. The derived flux scale correction was antenna-independent, and it can be applied to fix the overall visibility spectrum scale of H4C data post-calibration in a fashion similar to Jacobs et al. (2013). , Thesis (PhD) -- Faculty of Science, Physics and Electronics, 2024
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- Date Issued: 2024
Implementation of the national diploma in tourism and hospitality management curriculum in two polytechnic colleges in Zimbabwe
- Authors: Ngwenya, Khanyisani https://orcid.org/0000-0002-0543-4671
- Date: 2024-01
- Subjects: Hospitality industry -- Vocational guidance , Tourism -- Vocational guidance
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/28287 , vital:74165
- Description: Many countries in the world consider the tourism and hospitality industry as the leading employer with huge impact on economic growth. It has significantly contributed to their national Gross Domestic Product (GDP). Several studies conducted world over affirm that tourism contributes above the global average of ten percent. In Zimbabwe, the estimated percentage has also been as high as 10percent. The Tourism and Hospitality Management (THM) program aims to equip youth with critical industry-specific skills and mitigate unemployment. Despite this, literature has revealed that certain graduates struggle to secure industry positions due to a discrepancy between acquired skills and employer expectations. Consequently, some graduates accept menial roles outside the tourism sector, while the industry itself resorts to employing unqualified personnel. The reason lies in ineffective curriculum implementation approaches characterized by a lack of appropriate pedagogical methods. Identifying and implementing effective strategies ensures that graduates possess the requisite skills and competencies demanded by the industry, making their employability much easier. This study used a qualitative approach because of its exploratory, descriptive, and contextual nature. The interpretive paradigm provided participants’ views, opinions, and thoughts on the THM curriculum implementation. The multiple case study research design allowed ample freedom to dig deeper into rich empirical data by examining contemporary trends in implementing the ND3 in THM curriculum at two polytechnic colleges. Non-probability convenience sampling was used to select the two polytechnic colleges. Purposive sampling was used to select twelve (12) students, six (6) lecturers, and two (2) ITTD inspectors. Lecturers and inspectors were interviewed. Data from students was obtained through Focus group discussions. Curriculum documents were reviewed to provide true realities of the THM curriculum implementation. Content analysis was used to analyse data. Rogan and Grayson (2003) curriculum implementation theoretical framework guided the study. The study revealed that lecturers were dissatisfied due to inappropriate pedagogical strategies. A new model to bridge the theory/ practice gap in teaching was developed. The study recommended the adoption of a new and modern teaching model and fix the recruitment process by employing qualified lecturers to teach ND3 in THM students. , Thesis (PhD) -- Faculty of Education, 2024
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- Date Issued: 2024-01
Rationalisation of magisterial districts to transform the judiciary and widen access to justice under the RSA constitution of 1996
- Authors: Skosana, Jacob
- Date: 2024-01
- Subjects: Justice, Administration of , Law and socialism , Human rights -- South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/28162 , vital:72777
- Description: The study examines how pre-1994 magisterial districts jurisdictions denied access to justice to many South Africans, and ongoing efforts to reverse this injustice. Delayed rationalisation of the judiciary and reform of the courts territorial jurisdiction during the apartheid era exacerbated the problem. The courts administered justice along spatial racial divide, and given the location of the courts, many black communities had to commute long distances to access justice and at a great cost and inconvenience. The Constitution of South Africa of 1996 provides not only for the right to equality before the law and equal protection and benefit of the law but also the right to access the courts and seek recourse. In a period spanning eight years from December 2014, new magisterial districts were proclaimed in all the nine provinces of South Africa. Despite this milestone and the imperative of the 1996 Constitution, the rationalisation process is still in its infancy: old legislation and judicial structures remain intact; divisions of the High Court continue to exercise jurisdictions determined for the pre-1994 constitutional dispensation. The status quo continues to perpetuate the denial of access to justice to communities especially those living in areas that hitherto formed part of the former homelands and self-governing ‘states’. The study was conducted through a desktop survey of primary and secondary material relevant to the rationalisation process. It drew lessons from the re-demarcation of municipal boundaries which, like magisterial districts, were based on racial laws and policies of the past. It also contrasted rationalisation principles in comparable jurisdictions. The findings provide a useful contribution to the ongoing effort to effect rationalisation of the court system. They also contribute to knowledge and enriches our understanding of the relationship that underpins the administration of justice in a dispensation driven by democratic, human rights and constitutional ethos. , Thesis (PhD (LLD)) -- Faculty of Law, 2024
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- Date Issued: 2024-01
A framework to improve supply chain performance through lead time management in Ugandan public health institutions
- Authors: Kabagenyi, Dorothy
- Date: 2023-12
- Subjects: Lean manufacturing -- Management , Business logistics -- Uganda , Medical care -- Uganda , Industrial procurement Inventory control
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/65633 , vital:74213
- Description: A well-organised public healthcare supply chain leads to easy accessibility of medical supplies. In order to have healthy populations, it is important for governments to have the required medical supplies in their healthcare facilities at the required time. As such, appropriate lead time management by supply chain actors greatly improves supply chain performance. However, the current public healthcare supply chains in Uganda have challenges that lead to poor quality and inefficient public health supply chain performance. The primary objective of this study was to develop an implementation framework to guide public health institutions in improving supply chain performance through lead time management in Uganda. The study also sought to determine the influence of supply chain optimisation on lead time management. It also sought to examine the influence of supply chain dynamic capabilities on lead time management. The study further examined the influence of supplier performance on lead time management, and sought to examine the influence of lead time management on supply chain performance. The study also sought to assess the mediating effect of lead time management on the relationship between supply chain dynamic capabilities and overall supply chain performance, between supply chain optimisation and overall supply chain performance, as well as between supplier performance and overall supply chain performance. Lastly, the study sought to assess the mediation effect of supply chain optimisation on the relationship between supplier performance and lead time management as well as between supply chain dynamic capabilities and lead time management. A positivist philosophy that allowed quantitative data to be collected from 340 respondents was used in this study. The study used both stratified sampling and simple random sampling without replacement to choose the public healthcare facilities as well as purposive sampling to select the final respondents for the study. An exploratory factor analysis (EFA) was performed in the Statistical Package for Social Sciences (SPSS) Version 25 for factor reduction and dimensional groupings. Confirmatory factor analysis (CFA) and structural equation modeling (SEM) path analysis models were performed in the Analysis of Moments of Structure (AMOS Version 27) software for model fit assessments and hypotheses testing, respectively. A multiple regression analysis was performed in SPSS Version 25 software, and was used for comparison and confirmation of the weak and insignificant result obtained for the unsupported hypothesis (H4) in the SEM hypotheses tests. , Thesis (PhD) -- Faculty of Business and Economic Sciences, School of Management Sciences, 2023
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- Date Issued: 2023-12
An alternative model for the financial sustainability of social services sector NGOs in the Eastern Cape, South Africa
- Authors: Kagande, Albert Tafadzwa
- Date: 2023-12
- Subjects: Non-governmental organizations -- South Africa , Accounting -- Social aspects , Sustainability
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/65644 , vital:74217
- Description: The work of Non-Governmental Organisations (NGOs) is traditionally deemed “unprofitable”, yet they provide valuable services to communities. With an exponentially growing NGO sector of more than 270 000 NGOs, of which 40% are social service sector NGOs, and an increased demand for NGO services, a decrease in government and donor funding has heightened the debate on the need for financial sustainability of NGOs in South Africa. NGOs are important development actors, and their financial sustainability is crucial as it ensures that the sector continues to be relevant and effective in ensuring that social needs are met. Using a mixed methods sequential explanatory research design, the study focused on the social services sector NGOs in the Eastern Cape with the aim of understanding their financial challenges and strategies being employed to address such and, in the process, develop an alternative model for the financial sustainability of these NGOs. A conceptual framework was developed from six theories which were used to explore the concept of financial sustainability drawing insights from the internal and external environment of the participating NGOs. These theories were used together to emphasise that no one theory could single-handedly and holistically explain the concept of the financial sustainability of social service sector NGOs. The use of multiple theories also came from the realisation that NGOs in South Africa, in general, are struggling to survive owing to a myriad of factors which include increased competition for resources and reduced funding from their traditional source. Furthermore, donor dependency, staff and organisational capacity, management practices and values, and the interplay of an NGO with its stakeholders and environment all have a bearing on financial sustainability. Being the poorest province in South Africa heightens the need for social services in the Eastern Cape. From the study, it was established that 48% of social services sector NGOs depended on government funding while only 16% had the capacity to generate their own income. However, depending on government funding was not sustainable and this was crippling the social services sector. The study also established that “young” NGOs struggled to secure funding when compared to their “mature” counterparts. In addition, staff capacity and the values of an organisation affected income generation and how funds were sourced. Lack of capacity to fundraise and/or implement commercial activities had affected the financial sustainability of the social sector NGOs. The interplay of an NGO and its stakeholders and environment also had a bearing on the financial sustainability of the sector. The study provides a multipronged approach and perspective to financial sustainability. The proposed financial sustainability model challenges social services sector NGOs to consciously reflect on their internal and external environments as well a come up with strategies that positively affect their financial sustainability. From the study, the strategies that were being implemented to realise financially sustainability included, retaining current donors, reaching out to new donors, innovative fundraising approaches, redesigning programme activities to include cost-recovery components, collaborating with other NGOs as well as commercial ventures. This study concludes that social services sector NGOs need all these approaches in addition to improving staff capacity and adopting a culture that enhances organisational performance. There is need to build a system where NGOs are adequately supported to do their work without worrying about income and where well-designed financial sustainability components help NGOs, funders, government and communities identify where change is needed. , Thesis (DPhil) -- Faculty of Business and Economic Sciences, School of Economics, Development and Tourism, 2023
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- Date Issued: 2023-12
An application of the Mundell Fleming model in emerging market economies
- Authors: Tenderere, Morris
- Date: 2023-12
- Subjects: Macroeconomics , Foreign exchange rates , International economic relations
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/66039 , vital:74319
- Description: The core objective of this study was to test the applicability of the Mundell-Fleming model in emerging market economies. Despite its importance, no study has examined the applicability of the Mundell-Fleming model in emerging market economies, as far as this study is aware. The Mundell-Fleming model predicts that in an environment with freely floating exchange rates, a drop in interest rates will lead to capital flight, which in turn will result in a fall in the exchange rate and a rise in net exports. The model takes into account both the international flow of capital and the flow of goods and services that might have a big impact on the country. The model's theoretical foundations offer practical instruments for assessing the impact of economic policy in light of the adopted exchange rate regimes of a nation. The model plays a key role in anticipating the link between output, interest rates, and exchange rates. A quantitative approach using panel monthly data over the period 2000 to 2017 for five emerging countries was carried out. Brazil, Malaysia, China, India, and South Africa were the considered countries due to availability of data. The Dynamic Ordinary Least Square (DOLS) and Fully Modified Ordinary Least Square (FMOLS) were used to analyse the data. The study confirmed the applicability of the Mundell-Fleming model in the studied countries given a positive relationship between interest rate and portfolio investment. This result means that when interest rates rise, capital flows also increase. In addition, the confirmation of Mundell-Fleming model is reflected in the negative relationship between portfolio investment and the rate of exchange. The Mundell-Fleming model describes how movement of capital and exchange rates behave. The study recommended that to ease the threat of currency appreciation, the Central Banks in merging market economies must ensure that the domestic interest rate is always in line with the world interest rate. This will promote exchange rate stability and whenever there is an appreciation/depreciation the Central Banks must use interest rates to bring back the exchange rate to the desired rate. In emerging market economies, the reserve banks must employ what is referred to as the "sterilization" of capital flows to lessen the threat of currency appreciation. The local component of the monetary base (bank reserves plus currency) is decreased in a successful sterilization operation to counteract the reserve influx, at least temporarily. , Thesis (PhD) -- Faculty of Business and Economic Sciences, School of Economics, Development and Tourism, 2023
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- Date Issued: 2023-12
An exploration of stakeholder perceptions of the quality of teaching and learning in higher education
- Authors: Jackson,Linda Grace
- Date: 2023-12
- Subjects: Quality assurance --Education (Higher)-- South Africa , Teaching and learning – Nelson Mandela University , Quality education—South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/62464 , vital:72757
- Description: Quality in higher education is a complex and evolving concept that has been a subject of measurement, assurance and promotion in universities globally for the past three decades. However, its precise definition remains elusive due to its fluid nature, influenced by various contextual factors and stakeholder perspectives. This study explored the concepts of quality teaching and quality learning within the specific context of Nelson Mandela University, focusing on two critical internal stakeholder groups, lecturers and students. By maintaining a constant context, the study sought to gain a deeper understanding of how these stakeholders perceived and contributed to the overall quality of education at the institution. Defining quality in higher education (HE) is important, as it directly impacts on the evaluation processes within educational institutions. Presently, most Higher Education Institutions (HEIs) assess quality using tangible inputs and outputs, resulting in a quantifiable representation of quality. Despite this approach, realistically, the anticipated improvements in the quality of teaching and learning are not apparent, leading to concerns about graduate readiness for the demands of the workforce. This situation raises imperative questions about the quality of teaching and learning within HEIs, necessitating a response to address this issue. This study used the conceptual model Schindler et al. (2015) developed to investigate stakeholder perceptions of quality teaching and quality learning in higher education (HE). The research followed a novel perspective by uncoupling quality in HE from the prevailing neoliberal approach and considering quality in HE within social inclusion interventions (Gidley et al., 2010a) already in place in HE settings. The research methodology expanded on social inclusion theory and employed a qualitative, participative and visual approach adapted from Mmogo-method®, an indigenous method. The research design fostered active participation from the participants, who assumed the role of co-researchers. Participants constructed their answers to the research question using unstructured materials, subsequently sharing, explaining, and interpreting their viewpoints within the group setting. , Thesis (PhD) -- Faculty of Education, School of teaching and learning, 2023
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- Date Issued: 2023-12
Analysis of export performance and its determinants in Uganda
- Authors: Mugambe, Kenneth
- Date: 2023-12
- Subjects: Economics -- Uganda , Shipping -- Economic aspects -- Uganda , Exports -- Uganda
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/65841 , vital:74273
- Description: The purpose of this study was to investigate whether variations in the factor endowments, endo-genous factors and governance factors can explain the growth rates in export performance in Uga-nda. The study was guided by the objectives, which included examining the effect of factor endowments on export performance in Uganda, examining the effect of endogenous factors on export performance in Uganda and examining the effect of governance factors on Uganda’s export performance. From the theoretical review, the study benchmarks the growth frameworks of neo-classical theory, endogenous growth theory and institutionalist growth theory, which guided the formulation of the empirical growth models. The study followed a longitudinal research design with time series analysis. A longitudinal design was selected for this study to examine the determinants of exporting in Uganda from 1996 to 2021. The estimation was achieved by imple-menting the first instrumental variable generalised method moments (1V-GMM) on a linear dy-namic panel model through the specific-to-general modelling technique. Among the factors moti-vated by the neo-classical theory paradigm, estimates from this study indicate that foreign direct investment has a positive influence on Uganda’s export performance positively. At the same time, gross capital formation significantly reduces the growth of exports. On the other hand, labour force (in the final model) does not influence changes in export performance since it is insignificant. Among the endogenous growth factors, estimates show that higher exchange rates and inflation have a significant negative effect on Uganda’s export performance. Estimates indicate further that among the governance factors, control of corruption has no effect on Uganda’s export performance. On the other hand, government effectiveness (which also serves as regulatory quality) has a significant negative effect on export performance in that government efforts to im-prove its efficacy affect export performance negatively. So the study shows that variations in Uga-nda’s export performance can partially be explained by the neo-classical trade theory and the endogenous growth model with little influence from the institutional growth model, suggesting the incompleteness of the growth frameworks adopted in assessing the sources of export performance in Uganda. The regression results from Model 3 indicate that all the independent variables explain 77.21% (R Square = .7721) of the variations in export performance, implying that the remaining 22.79% explains other factors not considered in this study. In conclusion, factor endowments play a crucial role in driving Uganda’s export performance. Foreign direct investment consistently influences exports, underscoring the role of capital, technology and international market access in enhancing export competitiveness. However, the negative co-efficient for gross capital formation raises concerns about potential trade-offs between domestic investment and export promotion. In addition, the positive co-efficient for real effective exchange rate (REER) in Model 2 suggests that a favourable exchange rate enhances export competitiveness. This highlights the importance of exchange rate policies that promote stability and competitiveness. However, the mixed and marginal significance of REER in Model 3 indicates the presence of other factors influencing the relationship, emphasising the need for a comprehensive analysis of exchange rate dynamics. The negative co-efficients for inflation across the models imply that higher inflation rates may hinder export performance, emphasising the importance of maintaining price stability to preserve export competitiveness. Based on the results of the analysis, a number of policy recommendations for Uganda can be made. The country should prioritise export promotion initiatives as supported by the positive and significant influence of previous export performance and foreign direct investment on exports. The government could implement targeted policies and programmes to support export-oriented industries, provide incentives for export activities and facilitate market access for Ugandan goods and services. Uganda could attract more investments and stimulate export growth by fostering a conducive environment for exporters. , Thesis (PhD) -- Faculty of Business and Economic Sciences, School of Economics, Development and Tourism, 2023
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- Date Issued: 2023-12
Arts-based participatory research for more equitable ocean governance in South Africa
- Authors: Strand, Mia
- Date: 2023-12
- Subjects: Marine resources conservation , Marine resources development , Law of the sea
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/66017 , vital:74307
- Description: This research explored the usefulness of arts-based participatory research (ABPR) in identifying more equitable ocean governance in South Africa. Co-developing the ABPR with Indigenous and local knowledge holders as co-researchers, the research expanded on opportunities to inform more equitable marine spatial planning (MSP) and marine protected areas (MPAs) processes. Working with 24 co-researchers in Algoa Bay (Eastern Cape) and 24 co-researchers in Mandeni (KwaZulu-Natal) for over two years, the thesis formulated and contextually adapted an approach incorporating photovoice and digital storytelling for co-researchers to share their ocean knowledges, priorities and stories. As people hold various priorities, interests and knowledges of the ocean, these knowledges shape how people interact with the ocean and coast. Despite a multitude of interconnected and complex ocean knowledges (pluriversality), a growing body of literature describes the exclusionary, top-down and inequitable nature of area-based ocean management in South Africa, which do not recognise Indigenous and local knowledge systems (ILKS). The research was conceptualised as a response to these realities, and the ABPR processes were developed with knowledge holders who felt excluded from current ocean governance approaches. Working within a broader theoretical framework of social and environmental justice, the research drew on contextually relevant literature and theoretical paradigms such as social sustainability, social-ecological systems, decolonial and postcolonial theory, social learning, transdisciplinary knowledge co-production and arts-based research. The ABPR methods were carefully crafted together with co-researchers, and photovoice experts assisted with cross-learning workshops. The ABPR included in situ photography and storytelling processes to ensure co-researchers could convey embodied, daily lived experiences or re-imagined connections with the ocean and coast. Embracing and reclaiming world-making through processes of participatory community mapping, the ABPR also facilitated collaborative analysis of co-researchers’ relationships and interactions with the ocean in light of current MSP and MPA processes. The final photostories from the ABPR processes were shared by the co-researchers at two multimedia exhibitions and two multi-stakeholder workshops that brought together relevant government representatives, coastal managers, conservation authorities, scientists and local community members. The results from the ABPR processes provided a number of novel and significant insights into ocean knowledges, connections and priorities that are currently not recognised in ocean governance processes in South Africa. Specifically, the ABPR proved useful in highlighting strong spiritual and traditional connections to the ocean and facilitating direct engagements and social learning processes between various ocean priorities to start bridging the gap between ILKS, marine science and ocean decision-making. Furthermore, the ABPR was valuable in mapping sociocultural priorities and interactions with the ocean, which could inform more inclusive and equitable MSP and MPAs processes. The ABPR surfaced opportunities for cognitive justice, where ILKS holders could own the knowledge production process, and identify opportunities for greater co-management in ocean decision-making. The insights from the research are relevant for several disciplines, research practices, and ocean governance processes. In summary, the ABPR process was useful to identify practical approaches and pathways necessary for embracing and working with the complexity of social-ecological marine systems and the plurality of ocean knowledges for more equitable ocean futures. , Thesis (DPhil) -- Faculty of Business and Economic Sciences, School of Economics, Development and Tourism, 2023
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- Date Issued: 2023-12
Assessing the effects of fish stock management on Cape gannet foraging behaviour in South Africa
- 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
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- Date Issued: 2023-12
Creating a value proposition in the optometry industry: perceptions of customers
- Authors: Mmamogobo, Maleage Jacob
- Date: 2023-12
- Subjects: Optometry--Economic aspects , Optometry--Practice , Consumer behavior -- South Africa , Corporate image -- Management
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/65782 , vital:74237
- Description: The highly competitive environment in the optometry healthcare industry, the over-serviced urban market and the cost of keeping businesses operating with little knowledge of how a profitable business operates lead most independent business owners to employ inappropriate strategies to manage situations that arise, and the optometry industry, particularly standalone practices, are particularly vulnerable to these challenges. As a result, creating a value proposition for customers has become a common approach to operations and ensuring service providers’ survival in new and existing practices. Therefore, the limitations under which service providers operate need to be investigated to determine which competencies are lacking. The study aimed to create a value proposition in the optometry industry in South Africa by exploring optometry customers’ perceptions. Through a qualitative research approach a total of 17 telephone interviews and eight mask-to-mask interviews were conducted with participants (five per chosen service provider from all nine provinces). The participants were drawn from all service providers’ current customers, including those whom in the past three months used the services or products, purchased an optical frame temple or full pair of spectacles, underwent an eye examination, and others. The qualitative data analysis employed content and thematic analyses, focusing on key elements such as the importance of creating a value proposition, developing a value proposition process, and the challenges associated with its creation. The five building blocks for creating a value proposition are visibility, service and product, price and value, reputation management and communication. This study’s findings will assist individual service providers to evaluate themselves against customers’ expectations and benefit customers and researchers. The main recommendations are 24-hour online access to a website, quality of services or products, full standard optometry service, affordable health care products or services, a short turnaround time for complete products, and acquired management skills to grow and generate sales. , Thesis (PhD) -- Faculty of Business and Economic Sciences, School of Management Sciences, 2023
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- Date Issued: 2023-12
Eco-leadership determinants necessary for effective sustainability implementation
- Authors: May,Jodé
- Date: 2023-12
- Subjects: Retail trade -- Management , Leadership -- South Africa , Sustainability
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/65683 , vital:74228
- Description: Sustainability is regarded globally as one of the key focus areas for organisations and requires also considering environmental and social performance in addition to economic performance. Eco-leadership is required to ensure operations impact society and the environment in a positive manner, in particular in the retail sector as customers have become conscious of their purchases being produced sustainably. The main objective of this study was thus to explore eco-leadership determinants necessary for sustainability implementation in retail organisations. The research was aimed at expanding knowledge about how retailers can implement or improve their sustainability status by following an eco-leadership approach. A literature review was conducted on what leadership in organisations entailed and how it can be described in terms of leaders’ characteristics, work practices and decisions. In addition a review on, leader qualities and leadership styles in general and of change leaders such as eco-leaders, sustainability strategies from both an environmental and socially responsible view in general and of the retail sector, was provided. The study followed a qualitative research approach using purposive sampling to identify the 11 participants from across the provinces in South Africa and retail product categories comprising of two hard-line retailers, five soft goods and consumables retailers, three FMCG retailers and one art retailer. A semi-structured interview guide was utilised to gather primary data using face-to-face, telephonic and email interviews. Content and constant comparative analysis was used to analyse the data. It appears that retailers ascribe eco-leadership in relation to resource management-, being people centred and practising sustainability leadership. All retailers seem to demonstrate their commitment to eco-leadership and serve society. Their sustainability status is publicised via digital and print media or visually displayed in-store. They practise eco-leadership as it is beneficial for their reputation or to ensure business continuity. Retailers use innovation and incorporate eco-leadership into their business models and have further plans to improve their sustainability. , Thesis (PhD) -- Faculty of Business and Economic Sciences, School of Management Sciences, 2023
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- Date Issued: 2023-12
Evaluation of the antidiabetic potential, safety and efficacy of selected natural products using zebrafish larvae and in vitro bioassays
- Authors: Reddy, Shanika , Dambuza, Ntokozo
- Date: 2023-12
- Subjects: Traditional medicine -- Research -- South Africa , Medicinal plants -- South Africa -- Research , Insulin resistance
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/62575 , vital:72825
- Description: Abstract. , Thesis (MSc) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 2023
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- 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
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- Date Issued: 2023-12