Multi-purpose community centres as catalysts for socio-economic development in Eastern Cape province, South Africa
- Gobe, Cynthia Bongiwe Ntombikayise
- Authors: Gobe, Cynthia Bongiwe Ntombikayise
- Date: 2024-04
- Subjects: Community centers -- South Africa , Buildings -- Environmental engineering -- South Africa , Sustainable construction -- Economic aspects , Infrastructure (Economics) -- South Africa Sustainable development
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/64533 , vital:73747
- Description: The central issue facing African society, especially underdeveloped countries is that most of the population lives below the poverty line, experiences high levels of unemployment and unsustainable livelihoods. The poor and marginalised groups in many communities are deprived access to infrastructure and socio-economic amenities, this includes accessibility to government services, information, and developmental opportunities. The development of Multi-purpose Community Centres (MPCCs) is viewed as a value-adding solution to several challenges facing unequal societies, such as inadequate infrastructure, remote settlement patterns, poor access to basic services, poor access to technology, poor access to information, increased unemployment rate, increased poverty rate, and many others. The study examines the socio-economic impact of MPCCs on municipalities of the Eastern Cape Province in South Africa and explores how these centres, as built environment outputs can become a stimulus for sustainable livelihoods in urban, rural, and peri-urban human settlements, including informal settlements. The study falls under implementation evaluation research methodologies which assesses whether a programme has been adequately implemented before making inference on its effectiveness. Anchored in a Social Constructivism knowledge paradigm and leaning on a Systems and Development Theories, the study adopted a Mixed Method Research approach. In view of the data required document reviews, field observations, interviews and questionnaire surveys were employed. The research findings revealed that despite the delivery of MPCCs by the Department of Human Settlements, these centers have not provided much socio-economic opportunities to members of the communities where they are built. The MPCCs under study are facing many challenges that render them ineffective to fulfill their mandate of improving the lives of residents. The study yielded an inclusive and responsive human settlements development model for the creation of well-functioning socio-economic impactful MPCCs within existing and forth-coming housing projects and informal settlements. , Thesis (DPhil) -- Faculty of Engineering, the Built Environment, and Technology, School of Built Environment and Civil Engineering, 2024
- Full Text:
- Date Issued: 2024-04
- Authors: Gobe, Cynthia Bongiwe Ntombikayise
- Date: 2024-04
- Subjects: Community centers -- South Africa , Buildings -- Environmental engineering -- South Africa , Sustainable construction -- Economic aspects , Infrastructure (Economics) -- South Africa Sustainable development
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/64533 , vital:73747
- Description: The central issue facing African society, especially underdeveloped countries is that most of the population lives below the poverty line, experiences high levels of unemployment and unsustainable livelihoods. The poor and marginalised groups in many communities are deprived access to infrastructure and socio-economic amenities, this includes accessibility to government services, information, and developmental opportunities. The development of Multi-purpose Community Centres (MPCCs) is viewed as a value-adding solution to several challenges facing unequal societies, such as inadequate infrastructure, remote settlement patterns, poor access to basic services, poor access to technology, poor access to information, increased unemployment rate, increased poverty rate, and many others. The study examines the socio-economic impact of MPCCs on municipalities of the Eastern Cape Province in South Africa and explores how these centres, as built environment outputs can become a stimulus for sustainable livelihoods in urban, rural, and peri-urban human settlements, including informal settlements. The study falls under implementation evaluation research methodologies which assesses whether a programme has been adequately implemented before making inference on its effectiveness. Anchored in a Social Constructivism knowledge paradigm and leaning on a Systems and Development Theories, the study adopted a Mixed Method Research approach. In view of the data required document reviews, field observations, interviews and questionnaire surveys were employed. The research findings revealed that despite the delivery of MPCCs by the Department of Human Settlements, these centers have not provided much socio-economic opportunities to members of the communities where they are built. The MPCCs under study are facing many challenges that render them ineffective to fulfill their mandate of improving the lives of residents. The study yielded an inclusive and responsive human settlements development model for the creation of well-functioning socio-economic impactful MPCCs within existing and forth-coming housing projects and informal settlements. , Thesis (DPhil) -- Faculty of Engineering, the Built Environment, and Technology, School of Built Environment and Civil Engineering, 2024
- Full Text:
- Date Issued: 2024-04
Optimisation of laser welding for thin-walled Ti6Al4V glider pressure hull
- Authors: Nel, Matthew Ryan
- Date: 2024-04
- Subjects: Laser welding , Welding , Mechanical engineering
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/64739 , vital:73882
- Description: Laser welding is a type of fusion welding process characterised by deep penetration, low heat input and high welding speed. This dissertation investigates the suitability of this process for the fabrication of an underwater glider buoyancy engine from thin Ti6Al4V alloy sheet. Areas of interest include the effect of process parameters on weld microstructure, static properties (microhardness, tensile and bend tests) and dynamic properties (fatigue tests). The effect of welding speed and laser defocusing were evaluated considering experimental matrices consisting of four different travel speeds and three defocus distances. These were narrowed down to three travel speeds and a single defocus distance, resulting in a final test matrix delivering three different heat inputs. Thereafter, the effect of heat input on static and dynamic properties was investigated. Vickers microhardness tests were carried out to predict weld response during tensile testing, with the expectation being that harder welds would offload more strain. This was confirmed using digital image correlation, which allowed for virtual measurement and visualisation of strain offloading. Bend tests were carried out on parent and welded samples to confirm whether Ti6Al4V could be formed to the correct geometry. Forming Ti6Al4V into a U-shape was the first consideration, since dynamic testing required samples of this geometry with longitudinal weld orientation. A two-stage forming methodology was developed from these experiments. Formed samples were subjected to fatigue tests in a custom designed fatigue platform for testing weld orientation as it would appear in the final component. Prediction of the welded buoyancy engine life was the goal behind these tests. Fracture surfaces were analysed to gain understanding of where crack initiation and final fracture occurred. Porosity served as the primary cause for crack initiation in failed samples. Pore distribution was heaviest in low-heat weldments and decreased with increasing heat input, while pore size increased with increasing heat input. This resulted in medium-heat weldments exhibiting superior performance to that of low- and high-heat ones. It was concluded that the laser welding process is able to produce weldments of sufficient integrity in thin Ti6Al4V sheet-formed components intended for use in glider buoyancy engines. , Thesis (MEng) -- Faculty of Engineering, the Built Environment and Technology, School of Engineering, 2024
- Full Text:
- Date Issued: 2024-04
- Authors: Nel, Matthew Ryan
- Date: 2024-04
- Subjects: Laser welding , Welding , Mechanical engineering
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/64739 , vital:73882
- Description: Laser welding is a type of fusion welding process characterised by deep penetration, low heat input and high welding speed. This dissertation investigates the suitability of this process for the fabrication of an underwater glider buoyancy engine from thin Ti6Al4V alloy sheet. Areas of interest include the effect of process parameters on weld microstructure, static properties (microhardness, tensile and bend tests) and dynamic properties (fatigue tests). The effect of welding speed and laser defocusing were evaluated considering experimental matrices consisting of four different travel speeds and three defocus distances. These were narrowed down to three travel speeds and a single defocus distance, resulting in a final test matrix delivering three different heat inputs. Thereafter, the effect of heat input on static and dynamic properties was investigated. Vickers microhardness tests were carried out to predict weld response during tensile testing, with the expectation being that harder welds would offload more strain. This was confirmed using digital image correlation, which allowed for virtual measurement and visualisation of strain offloading. Bend tests were carried out on parent and welded samples to confirm whether Ti6Al4V could be formed to the correct geometry. Forming Ti6Al4V into a U-shape was the first consideration, since dynamic testing required samples of this geometry with longitudinal weld orientation. A two-stage forming methodology was developed from these experiments. Formed samples were subjected to fatigue tests in a custom designed fatigue platform for testing weld orientation as it would appear in the final component. Prediction of the welded buoyancy engine life was the goal behind these tests. Fracture surfaces were analysed to gain understanding of where crack initiation and final fracture occurred. Porosity served as the primary cause for crack initiation in failed samples. Pore distribution was heaviest in low-heat weldments and decreased with increasing heat input, while pore size increased with increasing heat input. This resulted in medium-heat weldments exhibiting superior performance to that of low- and high-heat ones. It was concluded that the laser welding process is able to produce weldments of sufficient integrity in thin Ti6Al4V sheet-formed components intended for use in glider buoyancy engines. , Thesis (MEng) -- Faculty of Engineering, the Built Environment and Technology, School of Engineering, 2024
- Full Text:
- Date Issued: 2024-04
Organisational citizenship behaviour (OCB) in the South African transport state-owned enterprises
- Authors: Calvert, Candice
- Date: 2024-04
- Subjects: Organizational behavior -- South Africa , Government business enterprises -- South Africa , Government ownership -- South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/64896 , vital:73944
- Description: The transport sector is critically important for economic growth and sustainability of a country and therefore requires carefully crafted strategical policies aimed at social enhancements. Employees who are employed in the major South African transport sector’s State-Owned Enterprises (SOEs) carry the responsibility of providing quality and effective services, thus, they are executing the mandate of the National Department of Transport (NDoT). Therefore, their willingness to contribute positively to the goals of the sector, is critically important. Extra-roles and positive behaviours displayed by employees ensure that organisations gain competitive advantage over competitors. These special behaviours are documented in literature as organisational citizenship behaviours (OCB). OCB is referred to as voluntary positive behaviours displayed by employees, which benefit the organisation and improve the overall performance of employees and the organisation but are not recognised by the reward system of the organisation. The scarcity of literature pertaining to OCB in SOEs and in particular, the transport sector globally indicates that OCB is not entrenched in organisational cultures in this sector. The primary objective of this study is to investigate the views of management and employees regarding the influential factors and the outcomes of OCB in South Africa’s major SOEs in the transport sector. A hypothetical model and a questionnaire were developed to establish the influential factors of OCB and its outcomes on the performance of South Africa’s major transport SOEs. Eight independent variables (leadership styles, organisational culture, management support, personal importance, transparency, job autonomy, employee trust and organisational commitment), the intervening variable (organisational citizenship behaviour) and the dependent variables (employee performance and employee retention) were investigated. Primary data was collected by means of electronic questionnaires, which were distributed to five provinces via a QuestionPro link that was emailed to the contact person nominated by the HR department of the two major transport SOEs. Hard copies of the questionnaire were also physically distributed to prospective participants by the researcher. Non-probability sampling was used, specifically convenience sampling technique. The study targeted 500 respondents and 318 questionnaires were usable which amounts to a response rate of 64%. The reliability of the measuring instrument was determined by means of Cronbach’s alpha coefficient and the construct validity was tested using exploratory factor analysis (EFA). Content validity for the measuring instrument was validated by experts in the fields of organisational behaviour and change management, prior to the distribution of the questionnaire to participants. EFA, descriptive statistics, multiple regression analysis and correlation analysis were determined. A STATISTICA computer programme 14.0 was used. The results of the study showed that OCB, which was tested as a seven-dimensional construct, namely, altruism, sportsmanship, loyalty, individual initiative, civic virtue, courtesy, and self-development, was perceived by respondents as two constructs, namely, OCB-selflessness (OCB-S) (altruism, sportsmanship, individual initiative, courtesy and self-development) and OCB-reliability (OCB-R) (civic virtue and loyalty). The empirical results revealed that personal importance is significantly related to OCB-S, but is not significantly related to OCB-R. Furthermore, the findings showed that transparency is not significantly related to OCB-S, however, there is a significant positive relationship between transparency and OCB-R. It was also found that job autonomy is not significantly related to OCB-S, and has a significant negative relationship with OCB-R. In addition, the research findings showed that employee trust and organisational commitment are significantly related to both OCB-S and OCB-R. OCB-S and OCB-R were found to be significantly related to employee performance and employee retention. This study contributed to the body of knowledge in the fields of organisational behaviour and human resources. Furthermore, the study will contribute to policy makers and management within the transport sector of South Africa and globally in order to develop policies and devise strategies to combat negative workplace environments, stimulate service delivery, and improve the competitive advantage of the organisation and the economic sustainability in the transport sector globally, through employee performance and employee retention. , Thesis (DBA) -- Faculty of Business and Economic Sciences, Business School, 2024
- Full Text:
- Date Issued: 2024-04
- Authors: Calvert, Candice
- Date: 2024-04
- Subjects: Organizational behavior -- South Africa , Government business enterprises -- South Africa , Government ownership -- South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/64896 , vital:73944
- Description: The transport sector is critically important for economic growth and sustainability of a country and therefore requires carefully crafted strategical policies aimed at social enhancements. Employees who are employed in the major South African transport sector’s State-Owned Enterprises (SOEs) carry the responsibility of providing quality and effective services, thus, they are executing the mandate of the National Department of Transport (NDoT). Therefore, their willingness to contribute positively to the goals of the sector, is critically important. Extra-roles and positive behaviours displayed by employees ensure that organisations gain competitive advantage over competitors. These special behaviours are documented in literature as organisational citizenship behaviours (OCB). OCB is referred to as voluntary positive behaviours displayed by employees, which benefit the organisation and improve the overall performance of employees and the organisation but are not recognised by the reward system of the organisation. The scarcity of literature pertaining to OCB in SOEs and in particular, the transport sector globally indicates that OCB is not entrenched in organisational cultures in this sector. The primary objective of this study is to investigate the views of management and employees regarding the influential factors and the outcomes of OCB in South Africa’s major SOEs in the transport sector. A hypothetical model and a questionnaire were developed to establish the influential factors of OCB and its outcomes on the performance of South Africa’s major transport SOEs. Eight independent variables (leadership styles, organisational culture, management support, personal importance, transparency, job autonomy, employee trust and organisational commitment), the intervening variable (organisational citizenship behaviour) and the dependent variables (employee performance and employee retention) were investigated. Primary data was collected by means of electronic questionnaires, which were distributed to five provinces via a QuestionPro link that was emailed to the contact person nominated by the HR department of the two major transport SOEs. Hard copies of the questionnaire were also physically distributed to prospective participants by the researcher. Non-probability sampling was used, specifically convenience sampling technique. The study targeted 500 respondents and 318 questionnaires were usable which amounts to a response rate of 64%. The reliability of the measuring instrument was determined by means of Cronbach’s alpha coefficient and the construct validity was tested using exploratory factor analysis (EFA). Content validity for the measuring instrument was validated by experts in the fields of organisational behaviour and change management, prior to the distribution of the questionnaire to participants. EFA, descriptive statistics, multiple regression analysis and correlation analysis were determined. A STATISTICA computer programme 14.0 was used. The results of the study showed that OCB, which was tested as a seven-dimensional construct, namely, altruism, sportsmanship, loyalty, individual initiative, civic virtue, courtesy, and self-development, was perceived by respondents as two constructs, namely, OCB-selflessness (OCB-S) (altruism, sportsmanship, individual initiative, courtesy and self-development) and OCB-reliability (OCB-R) (civic virtue and loyalty). The empirical results revealed that personal importance is significantly related to OCB-S, but is not significantly related to OCB-R. Furthermore, the findings showed that transparency is not significantly related to OCB-S, however, there is a significant positive relationship between transparency and OCB-R. It was also found that job autonomy is not significantly related to OCB-S, and has a significant negative relationship with OCB-R. In addition, the research findings showed that employee trust and organisational commitment are significantly related to both OCB-S and OCB-R. OCB-S and OCB-R were found to be significantly related to employee performance and employee retention. This study contributed to the body of knowledge in the fields of organisational behaviour and human resources. Furthermore, the study will contribute to policy makers and management within the transport sector of South Africa and globally in order to develop policies and devise strategies to combat negative workplace environments, stimulate service delivery, and improve the competitive advantage of the organisation and the economic sustainability in the transport sector globally, through employee performance and employee retention. , Thesis (DBA) -- Faculty of Business and Economic Sciences, Business School, 2024
- Full Text:
- Date Issued: 2024-04
Out of place: an analysis of place as a contributor to the complexities of my “coloured” identity in Malabar, Gqeberha
- Authors: Flowers, Victoria
- Date: 2024-04
- Subjects: Colored people (South Africa) -- Race identity , Ethnicity in art -- South Africa -- Port Elizabeth , Modernism (Art)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62780 , vital:72954
- Description: Coloured identity has been a historical point of contestation in South Africa because Colouredness is assumed as “an inbred quality that arises automatically from miscegenation while instrumentalists share the essentialist premise that coloured identity is something negative and undesirable but blame it on the racism and the exploitative practices of the ruling white minority” (Adhikari, 2009: 15). This archaic belief attributed to racial mixture has now become redundant, due to the emergence of new hybridised Coloured identities that factor other ethnic and cultural groups as well as internal and external elements into their conception. The role of Place in the formation of Coloured identities is at the core of this fine arts based enquiry. This study is located in Malabar, Gqeberha which was established after the forced removals onset by the Group Areas Act of 1950 and the displacement of residents from South End. Additionally, it considers specific locations significant in their linkages to hybridised peoples, and how the place and individuals have been influenced by historical legacies of colonisation and apartheid. These are examined to consider their function in contextualising contemporary lived experiences of Coloured identity within the community of Malabar and its effect on artistic practice through autoethnographic research. Through this autoethnographic and reflexive study and the accompanying empirical research process, I critically examine and explore my Coloured identity as part of being-in-the-world (Heidegger, 1962). This ‘being’ is multifaceted as a result of the significance of Place in South Africa and how it has shaped my perception of how and where I have a sense of being and belonging. , Thesis (MA) -- Faculty of Humanities, School Visual and Performing Arts, 2023
- Full Text:
- Date Issued: 2024-04
- Authors: Flowers, Victoria
- Date: 2024-04
- Subjects: Colored people (South Africa) -- Race identity , Ethnicity in art -- South Africa -- Port Elizabeth , Modernism (Art)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62780 , vital:72954
- Description: Coloured identity has been a historical point of contestation in South Africa because Colouredness is assumed as “an inbred quality that arises automatically from miscegenation while instrumentalists share the essentialist premise that coloured identity is something negative and undesirable but blame it on the racism and the exploitative practices of the ruling white minority” (Adhikari, 2009: 15). This archaic belief attributed to racial mixture has now become redundant, due to the emergence of new hybridised Coloured identities that factor other ethnic and cultural groups as well as internal and external elements into their conception. The role of Place in the formation of Coloured identities is at the core of this fine arts based enquiry. This study is located in Malabar, Gqeberha which was established after the forced removals onset by the Group Areas Act of 1950 and the displacement of residents from South End. Additionally, it considers specific locations significant in their linkages to hybridised peoples, and how the place and individuals have been influenced by historical legacies of colonisation and apartheid. These are examined to consider their function in contextualising contemporary lived experiences of Coloured identity within the community of Malabar and its effect on artistic practice through autoethnographic research. Through this autoethnographic and reflexive study and the accompanying empirical research process, I critically examine and explore my Coloured identity as part of being-in-the-world (Heidegger, 1962). This ‘being’ is multifaceted as a result of the significance of Place in South Africa and how it has shaped my perception of how and where I have a sense of being and belonging. , Thesis (MA) -- Faculty of Humanities, School Visual and Performing Arts, 2023
- Full Text:
- Date Issued: 2024-04
Photocatalytic reduction of CO2 into green fuels on microspherical nanocomposites comprising of CdS, TiO2, ZnFe2O4 semiconductors and heterojunctions
- Authors: Mudau, Rendani Julian
- Date: 2024-04
- Subjects: Heterojunctions , Chemistry, Inorganic , Nanochemistry
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/64214 , vital:73665
- Description: Human anthropogenic activities have led to an increase in CO2 levels resulting in global warming. There is a need to reduce CO2 levels in the atmosphere by capturing the gas and converting the captured CO2 into fuels. Photocatalytic conversion of CO2 into valuable products via photoreduction is a promising technique to reduce carbon dioxide using sunlight and water. Redox reactions between CO2 and water using photocatalysts offer an effective method of lowering CO2, which has detrimental effects on the environment. This dissertation reports the synthesis and characterization of five photochemical catalysts comprising of CdS, TiO2, ZnFe2O4 semiconductors and heterojunctions and their use as photocatalysts for the photocatalytic reduction of CO2 into green fuels. Mott−Schottky plot of TiO2, CdS and CdS/TiO2 confirmed the formation of n-type, n-type, and n-n type material respectively. The band gap of TiO2, CdS, and CdS/TiO2 obtained were 3.21,2.24, 2.04 eV, respectively, the combination of TiO2 and CdS resulted in the lowering of band gap energy which is favourable for photocatalytic reduction studies. XRD of TiO2, CdS and CdS/TiO2 provided relevant information about the various phase reflections of the photocatalysts, it also supported reports confirming the increase in crystallite size of TiO2 anatase phase upon calcination. Chemical environment of the various photocatalysts, such as Ti2p1/2, Ti2p3/2, O1s, Cd3d3/2, Cd3d5/2, S2p1/2 and S2p3/2 were observed in TiO2, CdS and CdS/TiO2. BET surface area of TiO2, CdS and CdS/TiO2 was also observed to be 2.9243, 4.0605, and 9.8450 m2g, respectively. Photocatalytic reduction of CO2 resulted in formic acid, formaldehyde, acetic acid, carbon monoxide, ethanol, and methanol after 12 h. Modification of CdS with TiO2 to form CdS/TiO2 produced high yield of formic acid (217.7 μmol/g) compared to CdS (8.7 μmol/g) and TiO2 (122.5 μmol/g). CdS had high yield of formaldehyde (20.4 μmol/g) and ethanol (57.8 μmol/g) compared to TiO2 (12.9, 3.6 μmol/g of formaldehyde and ethanol, respectively) and CdS/TiO2 (19.7 μmol/g and there was no detection of ethanol). TiO2 shows high yield of methanol (145.2 μmol/g) and is the only catalysts that produced carbon monoxide (52.2 μmol/g) compared to CdS (87.8 μmol/g of methanol) and CdS/TiO2 (50.2 μmol/g of methanol). A detailed elucidation of the various products was reported by means of nuclear magnetic resonance (NMR) spectrometer. ZnFe2O4 and CdS/TiO2/ZnFe2O4 were characterized and employed for photocatalytic reduction of CO2 in water. XRD and XPS confirmed the presence Fe (2+) and Fe (3+) in tetrahedral/octahedral and Zn (2+) in tetrahedral on ZnFe2O4 and CdS/TiO2. CdS/TiO2/ZnFe2O4 presented a lowered band gap of 1.98 eV due to the presence of ZnFe2O4 while the band gap of ZnFe2O4 obtained is 1.95 eV. The Mott-Schottky plots confirmed the conduction (2.81 and 2.59 eV) and valence band (–0.86 and –6.1 eV) of ZnFe2O4 and CdS/TiO2/ZnFe2O4 together with their junctions, respectively. ZnFe2O4 and CdS/TiO2/ZnFe2O4 are p-type and p-n type junctions, respectively. Photocatalytic reduction of CO2 under visible light for 12 h using CdS/TiO2/ZnFe2O4 hollow microspheres nanocomposites produced methanol (182.1 μmol/g), formic acid (1.9 μmol/g), formaldehyde (9.5 μmol/g), ethanol (67.1 μmol/g), and oxalic acid (38.9 μmol/g). Amongst the synthesized catalysts, CdS/TiO2/ZnFe2O4 produced high yield of methanol, ethanol, and oxalic acid. , Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2024
- Full Text:
- Date Issued: 2024-04
- Authors: Mudau, Rendani Julian
- Date: 2024-04
- Subjects: Heterojunctions , Chemistry, Inorganic , Nanochemistry
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/64214 , vital:73665
- Description: Human anthropogenic activities have led to an increase in CO2 levels resulting in global warming. There is a need to reduce CO2 levels in the atmosphere by capturing the gas and converting the captured CO2 into fuels. Photocatalytic conversion of CO2 into valuable products via photoreduction is a promising technique to reduce carbon dioxide using sunlight and water. Redox reactions between CO2 and water using photocatalysts offer an effective method of lowering CO2, which has detrimental effects on the environment. This dissertation reports the synthesis and characterization of five photochemical catalysts comprising of CdS, TiO2, ZnFe2O4 semiconductors and heterojunctions and their use as photocatalysts for the photocatalytic reduction of CO2 into green fuels. Mott−Schottky plot of TiO2, CdS and CdS/TiO2 confirmed the formation of n-type, n-type, and n-n type material respectively. The band gap of TiO2, CdS, and CdS/TiO2 obtained were 3.21,2.24, 2.04 eV, respectively, the combination of TiO2 and CdS resulted in the lowering of band gap energy which is favourable for photocatalytic reduction studies. XRD of TiO2, CdS and CdS/TiO2 provided relevant information about the various phase reflections of the photocatalysts, it also supported reports confirming the increase in crystallite size of TiO2 anatase phase upon calcination. Chemical environment of the various photocatalysts, such as Ti2p1/2, Ti2p3/2, O1s, Cd3d3/2, Cd3d5/2, S2p1/2 and S2p3/2 were observed in TiO2, CdS and CdS/TiO2. BET surface area of TiO2, CdS and CdS/TiO2 was also observed to be 2.9243, 4.0605, and 9.8450 m2g, respectively. Photocatalytic reduction of CO2 resulted in formic acid, formaldehyde, acetic acid, carbon monoxide, ethanol, and methanol after 12 h. Modification of CdS with TiO2 to form CdS/TiO2 produced high yield of formic acid (217.7 μmol/g) compared to CdS (8.7 μmol/g) and TiO2 (122.5 μmol/g). CdS had high yield of formaldehyde (20.4 μmol/g) and ethanol (57.8 μmol/g) compared to TiO2 (12.9, 3.6 μmol/g of formaldehyde and ethanol, respectively) and CdS/TiO2 (19.7 μmol/g and there was no detection of ethanol). TiO2 shows high yield of methanol (145.2 μmol/g) and is the only catalysts that produced carbon monoxide (52.2 μmol/g) compared to CdS (87.8 μmol/g of methanol) and CdS/TiO2 (50.2 μmol/g of methanol). A detailed elucidation of the various products was reported by means of nuclear magnetic resonance (NMR) spectrometer. ZnFe2O4 and CdS/TiO2/ZnFe2O4 were characterized and employed for photocatalytic reduction of CO2 in water. XRD and XPS confirmed the presence Fe (2+) and Fe (3+) in tetrahedral/octahedral and Zn (2+) in tetrahedral on ZnFe2O4 and CdS/TiO2. CdS/TiO2/ZnFe2O4 presented a lowered band gap of 1.98 eV due to the presence of ZnFe2O4 while the band gap of ZnFe2O4 obtained is 1.95 eV. The Mott-Schottky plots confirmed the conduction (2.81 and 2.59 eV) and valence band (–0.86 and –6.1 eV) of ZnFe2O4 and CdS/TiO2/ZnFe2O4 together with their junctions, respectively. ZnFe2O4 and CdS/TiO2/ZnFe2O4 are p-type and p-n type junctions, respectively. Photocatalytic reduction of CO2 under visible light for 12 h using CdS/TiO2/ZnFe2O4 hollow microspheres nanocomposites produced methanol (182.1 μmol/g), formic acid (1.9 μmol/g), formaldehyde (9.5 μmol/g), ethanol (67.1 μmol/g), and oxalic acid (38.9 μmol/g). Amongst the synthesized catalysts, CdS/TiO2/ZnFe2O4 produced high yield of methanol, ethanol, and oxalic acid. , Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2024
- Full Text:
- Date Issued: 2024-04
Photoluminescence and electroluminescence imaging of PV devices
- Authors: Roodt, Roelof Petrus
- Date: 2024-04
- Subjects: Photoluminescence , Biosensors
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/64333 , vital:73676
- Description: Luminescence imaging has become a particularly useful and valuable tool for the characterisation of photovoltaic devices. This study entailed the design, construction, and optimisation of a system for the electroluminescence (EL) and photoluminescence (PL) imaging of various solar cell devices. The system can perform EL and PL imaging of solar cells of different cell technologies and materials systems, including Si, perovskite, and triple-junction concentrator solar cells. This required appropriate electrical power supplies for carrier injection for EL imaging and optical excitation for PL imaging. The different materials systems also required wavelength appropriate filters for PL imaging. In addition, the system utilized a temperature-controlled sample stage and was placed in a chamber for environmental control and isolation of UV radiation from laboratory. In addition to optimization of imaging conditions, luminescence images need to be optimized to facilitate detailed analysis and the application of appropriate algorithms to extract device parameters and hence generate device parameter images of the devices under investigation. For EL imaging, two power supplies were used to inject current into the solar cells. The reason for the two power supplies is that the first power supply had a current range of ± 1 A and an applied voltage capability of ± 21 V. This was used for the smaller solar cells. It was also convenient to use as the power supply could also measure the injected current and applied voltage and digitally store it with the images. For the larger solar cells, a second power supply was utilized, which could inject current into the samples in the range of ± 12 A at an applied voltage of ± 40 V. To measure the current and voltage of the power supply provided, two digital multimeters were utilized. For acquiring images, the same camera was used for EL and PL imaging. The sensor used in the camera is a silicon CMOS sensor. For PL imaging, four light emitting diode (LED) boards, consisting out of sixty-four LED’s, per board, of four different wavelengths, were used to optically excite the solar cells. The four wavelengths emitted by the LED’s were chosen to match the bandgaps of the different solar cell devices investigated. The LEDs were powered with a multi-channel constant voltage power supply, where the current could be varied. The Si solar cell is a 156 x 156 mm commercial solar cell. The perovskite solar module is a 40 x 40 mm module, which consists out of six cells connected in series. The triple-junction concentrator solar cell has a dimension of 10 x 10 mm which consists of three junctions staked on top of one another. These three layers consist of indium gallium phosphate (InGaP), indium gallium arsenide (InGaAs) and germanium (Ge). To capture EL and PL images of these various solar cell devices, filters of specific wavelengths were placed in front of the camera to isolate the light generated by the different devices. In addition to isolating the luminescence observed from the solar cells, an image correction procedure was adapted from literature, to be applicable to acquiring luminescence images of these various solar cells. As there are a range of factors which influence the quality and clarity of the luminescence images, i.e., chromatic aberration, diffraction, and absorption depth, to name a few, the wavelength dependency of these factors was investigated. This was done by acquiring a point spread function (PSF) for each of these devices and then using these PSF's together with a deconvolution algorithm to correct the luminescence images. The PSF was acquired by fitting a point source emission image to a function that includes exponential and Gaussian terms. The point source image was obtained by placing a black piece of vinyl with a pinhole in it over the solar cell. To communicate with all the various devices and to acquire images at various intensities a LABVIEW program was written. This was used then used to control the power supplies, digital multimeters, camera, and the LED's. This allowed for the user to specify at what points along the current-voltage (I-V) curve data points needed to be measured together with the luminescence images captured. For PL imaging the intensity of the LED's was then also adjusted according to user specified values. The system was utilised to acquire EL images of the Si solar cell, EL and PL images of the perovskite solar cell and EL images of the InGaP and InGaAs layers in the triple-junction concentrator solar cell. With the correction procedure utilised in this study, it was seen that the image quality and clarity improved, compared to the conventional way of capturing luminescence images. These statements are supported by the results obtained for the series resistance maps of the Si solar cell and the perovskite solar module, as the series resistance maps obtained from the corrected luminescence images have less noise and more detail compared to the results from the raw luminescence images. From the EL images captured for the two layers of the triple junction concentrator, it was clear that the intensity profile of the two layers is different, as the intensity for the InGaP layers was that the device had bright edges and darker intensity on the interior where exactly the opposite was observed for the InGaAs layer, having a bright interior and darker edges. This is most likely due to the opto-electric coupling of these layers withing the triple junction solar cell. For the series resistance images obtained for the Si solar cell, it is observed that at lower carrier injection, the series resistance is lower compared to higher carrier injection levels. This result can also be influenced by the increase in cell temperature with the increase in injected carriers. The series resistance maps obtained from the perovskite EL images shows an interesting result. As the perovskite solar cell has degraded, three of the six cells have optically inactive regions, showing lower luminescence intensities. The series resistance of the other three cells are much lower compared to these cells that have inactive regions under low injection conditions. As the injection level increases, it is seen that the series resistance values of five of the six cells become comparable to one another. With regards to the PSF, it was found that using a bandpass filter in front of the lens reduced to amount of spreading observed from a single point source across the detector. Furthermore, there is a strong wavelength dependency in the PSF as the severity increased with increase in the emission wavelength of the solar cells under investigation.In this study an opto-electrical characterisation system was constructed to acquire PL and EL images of various solar cell technologies. In addition to this, a range of factors that influence the quality of these images were investigated and used in the image correction procedure to correct the images for all these cell technologies. It was shown that the correction procedure works for all three of the technologies investigated in this study, and all these factors showed a strong wavelength dependency. These corrected luminescence images together with current-voltage (I-V) data was then used to determine characteristic parameters of a one-diode model of the various PV devices. This was not only achieved, but it also clearly indicated that all the correction procedures need to be considered to obtain a clear and accurate representation of the actual PV device. This has a major influence on the understanding and improvement of these PV devices. , Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2024
- Full Text:
- Date Issued: 2024-04
- Authors: Roodt, Roelof Petrus
- Date: 2024-04
- Subjects: Photoluminescence , Biosensors
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/64333 , vital:73676
- Description: Luminescence imaging has become a particularly useful and valuable tool for the characterisation of photovoltaic devices. This study entailed the design, construction, and optimisation of a system for the electroluminescence (EL) and photoluminescence (PL) imaging of various solar cell devices. The system can perform EL and PL imaging of solar cells of different cell technologies and materials systems, including Si, perovskite, and triple-junction concentrator solar cells. This required appropriate electrical power supplies for carrier injection for EL imaging and optical excitation for PL imaging. The different materials systems also required wavelength appropriate filters for PL imaging. In addition, the system utilized a temperature-controlled sample stage and was placed in a chamber for environmental control and isolation of UV radiation from laboratory. In addition to optimization of imaging conditions, luminescence images need to be optimized to facilitate detailed analysis and the application of appropriate algorithms to extract device parameters and hence generate device parameter images of the devices under investigation. For EL imaging, two power supplies were used to inject current into the solar cells. The reason for the two power supplies is that the first power supply had a current range of ± 1 A and an applied voltage capability of ± 21 V. This was used for the smaller solar cells. It was also convenient to use as the power supply could also measure the injected current and applied voltage and digitally store it with the images. For the larger solar cells, a second power supply was utilized, which could inject current into the samples in the range of ± 12 A at an applied voltage of ± 40 V. To measure the current and voltage of the power supply provided, two digital multimeters were utilized. For acquiring images, the same camera was used for EL and PL imaging. The sensor used in the camera is a silicon CMOS sensor. For PL imaging, four light emitting diode (LED) boards, consisting out of sixty-four LED’s, per board, of four different wavelengths, were used to optically excite the solar cells. The four wavelengths emitted by the LED’s were chosen to match the bandgaps of the different solar cell devices investigated. The LEDs were powered with a multi-channel constant voltage power supply, where the current could be varied. The Si solar cell is a 156 x 156 mm commercial solar cell. The perovskite solar module is a 40 x 40 mm module, which consists out of six cells connected in series. The triple-junction concentrator solar cell has a dimension of 10 x 10 mm which consists of three junctions staked on top of one another. These three layers consist of indium gallium phosphate (InGaP), indium gallium arsenide (InGaAs) and germanium (Ge). To capture EL and PL images of these various solar cell devices, filters of specific wavelengths were placed in front of the camera to isolate the light generated by the different devices. In addition to isolating the luminescence observed from the solar cells, an image correction procedure was adapted from literature, to be applicable to acquiring luminescence images of these various solar cells. As there are a range of factors which influence the quality and clarity of the luminescence images, i.e., chromatic aberration, diffraction, and absorption depth, to name a few, the wavelength dependency of these factors was investigated. This was done by acquiring a point spread function (PSF) for each of these devices and then using these PSF's together with a deconvolution algorithm to correct the luminescence images. The PSF was acquired by fitting a point source emission image to a function that includes exponential and Gaussian terms. The point source image was obtained by placing a black piece of vinyl with a pinhole in it over the solar cell. To communicate with all the various devices and to acquire images at various intensities a LABVIEW program was written. This was used then used to control the power supplies, digital multimeters, camera, and the LED's. This allowed for the user to specify at what points along the current-voltage (I-V) curve data points needed to be measured together with the luminescence images captured. For PL imaging the intensity of the LED's was then also adjusted according to user specified values. The system was utilised to acquire EL images of the Si solar cell, EL and PL images of the perovskite solar cell and EL images of the InGaP and InGaAs layers in the triple-junction concentrator solar cell. With the correction procedure utilised in this study, it was seen that the image quality and clarity improved, compared to the conventional way of capturing luminescence images. These statements are supported by the results obtained for the series resistance maps of the Si solar cell and the perovskite solar module, as the series resistance maps obtained from the corrected luminescence images have less noise and more detail compared to the results from the raw luminescence images. From the EL images captured for the two layers of the triple junction concentrator, it was clear that the intensity profile of the two layers is different, as the intensity for the InGaP layers was that the device had bright edges and darker intensity on the interior where exactly the opposite was observed for the InGaAs layer, having a bright interior and darker edges. This is most likely due to the opto-electric coupling of these layers withing the triple junction solar cell. For the series resistance images obtained for the Si solar cell, it is observed that at lower carrier injection, the series resistance is lower compared to higher carrier injection levels. This result can also be influenced by the increase in cell temperature with the increase in injected carriers. The series resistance maps obtained from the perovskite EL images shows an interesting result. As the perovskite solar cell has degraded, three of the six cells have optically inactive regions, showing lower luminescence intensities. The series resistance of the other three cells are much lower compared to these cells that have inactive regions under low injection conditions. As the injection level increases, it is seen that the series resistance values of five of the six cells become comparable to one another. With regards to the PSF, it was found that using a bandpass filter in front of the lens reduced to amount of spreading observed from a single point source across the detector. Furthermore, there is a strong wavelength dependency in the PSF as the severity increased with increase in the emission wavelength of the solar cells under investigation.In this study an opto-electrical characterisation system was constructed to acquire PL and EL images of various solar cell technologies. In addition to this, a range of factors that influence the quality of these images were investigated and used in the image correction procedure to correct the images for all these cell technologies. It was shown that the correction procedure works for all three of the technologies investigated in this study, and all these factors showed a strong wavelength dependency. These corrected luminescence images together with current-voltage (I-V) data was then used to determine characteristic parameters of a one-diode model of the various PV devices. This was not only achieved, but it also clearly indicated that all the correction procedures need to be considered to obtain a clear and accurate representation of the actual PV device. This has a major influence on the understanding and improvement of these PV devices. , Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2024
- Full Text:
- Date Issued: 2024-04
Preparation and Investigation of coumarin-based chemosensors towards sensing of ions using UV studies in aqueous systems
- Authors: Kotze, Tyla
- Date: 2024-04
- Subjects: Chemistry, Analytic , Water chemistry , Ionic solutions , Aquatic ecology , Geochemistry
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/64116 , vital:73654
- Description: Humanity's unrelenting expansion has shown little regard for the environment, and this has resulted in tons of toxic heavy metal cations and anions being released into the environment through industrial, agricultural, electronic, and mining dumping. The release of these toxic heavy metals can cause diseases and sometimes lead to death, especially in third-world countries with low-income that reside in informal settlements, who suffer the most. Furthermore, the release of these toxins eventually finds their way back into the environment through bioaccumulation in fish, plants and animals. Although there is an ever need for the growth of these industries; low-cost, sensitive, selective, and organic-based sensors is a positive step forward in highlighting the need for environmental restoration and remediation, whilst striving to avoid unnecessary disease and death through this development. In this project, coumarin-based chemosensors for the detection of cationic and anionic species in aqueous and organic media are described. This project involves the synthesis of six different coumarin-based ether derivatives (E2-E5) and coumarin-based ester derivatives (H1-H2). FT-IR, 1H NMR and 13C NMR were used to confirm the structures of all sensors. The abilities of these novel compounds as chemosensors for detection of cations and anions were investigated using UV-vis analysis. These compounds displayed a favourable interaction with Fe2+ and Fe3+ ions with an increase in absorbance. Ether derivatives E2-E5 did not display any degree of selectivity or sensitivity towards the chosen anions. It was found that in the presence of FeCl2, sensors H1 and H2 displayed a degree of selectivities and further investigations were therefore carried out. From the titration experiments, the limit of detection, limit of quantification and association constants were determined. Job’s plot analyses were performed to determine the binding ratios, which was supported by Benesi-Hildebrand studies. The binding ratio between the sensors and metal cations during complexation was found to be 1:1. Reversibility studies were carried out using EDTA to determine whether the sensors could be reused. Molecular Modelling studies were used to determine the most preferred binding sites. Lastly, real-life application screenings were also run to determine if the sensors will be able to be used in real-life scenarios. , Thesis (MSc) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 2024
- Full Text:
- Date Issued: 2024-04
- Authors: Kotze, Tyla
- Date: 2024-04
- Subjects: Chemistry, Analytic , Water chemistry , Ionic solutions , Aquatic ecology , Geochemistry
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/64116 , vital:73654
- Description: Humanity's unrelenting expansion has shown little regard for the environment, and this has resulted in tons of toxic heavy metal cations and anions being released into the environment through industrial, agricultural, electronic, and mining dumping. The release of these toxic heavy metals can cause diseases and sometimes lead to death, especially in third-world countries with low-income that reside in informal settlements, who suffer the most. Furthermore, the release of these toxins eventually finds their way back into the environment through bioaccumulation in fish, plants and animals. Although there is an ever need for the growth of these industries; low-cost, sensitive, selective, and organic-based sensors is a positive step forward in highlighting the need for environmental restoration and remediation, whilst striving to avoid unnecessary disease and death through this development. In this project, coumarin-based chemosensors for the detection of cationic and anionic species in aqueous and organic media are described. This project involves the synthesis of six different coumarin-based ether derivatives (E2-E5) and coumarin-based ester derivatives (H1-H2). FT-IR, 1H NMR and 13C NMR were used to confirm the structures of all sensors. The abilities of these novel compounds as chemosensors for detection of cations and anions were investigated using UV-vis analysis. These compounds displayed a favourable interaction with Fe2+ and Fe3+ ions with an increase in absorbance. Ether derivatives E2-E5 did not display any degree of selectivity or sensitivity towards the chosen anions. It was found that in the presence of FeCl2, sensors H1 and H2 displayed a degree of selectivities and further investigations were therefore carried out. From the titration experiments, the limit of detection, limit of quantification and association constants were determined. Job’s plot analyses were performed to determine the binding ratios, which was supported by Benesi-Hildebrand studies. The binding ratio between the sensors and metal cations during complexation was found to be 1:1. Reversibility studies were carried out using EDTA to determine whether the sensors could be reused. Molecular Modelling studies were used to determine the most preferred binding sites. Lastly, real-life application screenings were also run to determine if the sensors will be able to be used in real-life scenarios. , Thesis (MSc) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 2024
- Full Text:
- Date Issued: 2024-04
Prevalence of red blood cell alloantibodies in healthy blood donors: A retrospective study
- Authors: Bada, Thandolwethu Sarafina
- Date: 2024-04
- Subjects: Blood--Transfusion , Blood donors , Red blood cell alloantibodies
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63688 , vital:73586
- Description: Background: Blood transfusion is one of the essential supporting therapies in the management of patients and all efforts must be geared towards ensuring greater blood safety. There are studies on the prevalence of red blood cell alloantibodies in numerous transfused patients. However, no research has been done on the population of healthy first-time donors in South Africa who donates blood for transfusion. Red blood cell alloantibodies may be present in the donated units and potentially lead to transfusion reactions or to decreased survival of transfused RBCs. Therefore, it is necessary to know the prevalence of alloantibodies in donors and the clinical significance. Aims and objectives: The aim of this study is to determine the prevalence and identity of red blood cell alloantibodies in healthy first-time blood donors in the South African population, as well as to identify them, with the goal of improving blood safety and transfusion support for patients. Materials and methods: This retrospective and observational study investigates healthy first-time blood donors in the South African population over a five-year period, from January 2015 to December 2019. ABO typing and Rh typing were performed using the fully automated immunohaematology analyser BECKMAN COULTER PK7300 (Danaher Corporation, Brea, California). Erytra Eflexis automated system (8-column DG Gel cards) (Diagnostic Grifols, Barcelona, Spain) was used for antibody screening and antibody identification was performed using the RBC 11 Identisera Diana panel sheet. Approval was obtained from the Ethics Committees of Nelson Mandela University, South African National Blood Services and Western Province Blood Services prior to commencement of the study. Results: A total of 497 711 healthy first-time donors, consisting of 209 604 (42%) males and 288 107 (58%) females, were evaluated for irregular antibodies. The maximum number of donors belonged to the age group 18 to 29. Antibody screening results were positive in 849 donors from the entire population investigated, and 603 were RBC alloantibodies with an overall prevalence of 0.12%. The most frequent RBC alloantibody identified was anti-M from the MNS blood group systems, being present in 129 blood donors. Conclusion: The prevalence of RBC alloantibodies in the donor population in the study was 0.12% (603/497 711). As the inclusion criteria was limited, larger studies examining at all donors (first-time and repeated donations) are needed to determine the actual prevalence of alloantibodies in the population of South African donors. , Thesis (MHSc) -- Faculty of Health Sciences, School of Clinical Care & Medicinal Sciences, 2024
- Full Text:
- Date Issued: 2024-04
- Authors: Bada, Thandolwethu Sarafina
- Date: 2024-04
- Subjects: Blood--Transfusion , Blood donors , Red blood cell alloantibodies
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63688 , vital:73586
- Description: Background: Blood transfusion is one of the essential supporting therapies in the management of patients and all efforts must be geared towards ensuring greater blood safety. There are studies on the prevalence of red blood cell alloantibodies in numerous transfused patients. However, no research has been done on the population of healthy first-time donors in South Africa who donates blood for transfusion. Red blood cell alloantibodies may be present in the donated units and potentially lead to transfusion reactions or to decreased survival of transfused RBCs. Therefore, it is necessary to know the prevalence of alloantibodies in donors and the clinical significance. Aims and objectives: The aim of this study is to determine the prevalence and identity of red blood cell alloantibodies in healthy first-time blood donors in the South African population, as well as to identify them, with the goal of improving blood safety and transfusion support for patients. Materials and methods: This retrospective and observational study investigates healthy first-time blood donors in the South African population over a five-year period, from January 2015 to December 2019. ABO typing and Rh typing were performed using the fully automated immunohaematology analyser BECKMAN COULTER PK7300 (Danaher Corporation, Brea, California). Erytra Eflexis automated system (8-column DG Gel cards) (Diagnostic Grifols, Barcelona, Spain) was used for antibody screening and antibody identification was performed using the RBC 11 Identisera Diana panel sheet. Approval was obtained from the Ethics Committees of Nelson Mandela University, South African National Blood Services and Western Province Blood Services prior to commencement of the study. Results: A total of 497 711 healthy first-time donors, consisting of 209 604 (42%) males and 288 107 (58%) females, were evaluated for irregular antibodies. The maximum number of donors belonged to the age group 18 to 29. Antibody screening results were positive in 849 donors from the entire population investigated, and 603 were RBC alloantibodies with an overall prevalence of 0.12%. The most frequent RBC alloantibody identified was anti-M from the MNS blood group systems, being present in 129 blood donors. Conclusion: The prevalence of RBC alloantibodies in the donor population in the study was 0.12% (603/497 711). As the inclusion criteria was limited, larger studies examining at all donors (first-time and repeated donations) are needed to determine the actual prevalence of alloantibodies in the population of South African donors. , Thesis (MHSc) -- Faculty of Health Sciences, School of Clinical Care & Medicinal Sciences, 2024
- Full Text:
- Date Issued: 2024-04
Quantifying the impact of the spatio-temporal variability of land use/land cover on surface run-off generation and groundwater recharge in the luvuvhu river catchment area as a study area
- Ramuhovhi, Dakalo Ndivhuwo Stella
- Authors: Ramuhovhi, Dakalo Ndivhuwo Stella
- Date: 2024-04
- Subjects: Remote sensing , Geographic information systems , Groundwater flow
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/64322 , vital:73675
- Description: Assessing the spatio-temporal dynamics of land use land cover (LULC) change on hydrological response is vital for catchment sustainability and developing proper management strategies. The study aimed to assess the spatiotemporal effects and implications of LULC dynamics on surface runoff in the Luvuvhu River Catchment, Limpopo Province, using the Soil and Water Assessment Tool (SWAT) model. Satellite images of Landsat 5-thematic mapper and Landsat 8 operational land imager for the years 1990 and 2021 were used to explore the characteristics of LULC for this study by adopting the maximum likelihood (ML) supervised classification method. Five LULC classes were classified in this study; namely, water, built-up area, bare surface, dense vegetation, and sparse vegetation. The classification results show good accuracy values in the range of 76% (1990) and 84% (2021) with overall kappa of 63.8% and 72.8% for 1990 and 2021, respectively. For the purpose of this study, integration of geospatial technique and SWAT model were configured to operate at a monthly time interval over a span of 34 years, specifically from 1979 to 2013 to simulate surface runoff. The SWAT simulation process was executed using a digital elevation model, soil, LULC, and weather data. The analysis of LULC for 1990 and 2021 runoff modelling, it was found that, the runoff depth increased gradually from 3249 mm to 5162.5 mm during 1990 and 2021 LULC change, respectively. The R2, ENS, PBIAS, and RSR values for the calibration and the validation were 0.81 and 0.76, and 0.72 and 0.68, 0.64 and 0.58, 0.54 and 0.63 respectively. These values indicate good correlation between the observed and simulated stream flow data Therefore, suitable and timely management measures must be taken by policy decision-makers to enable sustainable development and to protect the catchment’s natural resources in order to reduce the severity of the changes. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2024
- Full Text:
- Date Issued: 2024-04
- Authors: Ramuhovhi, Dakalo Ndivhuwo Stella
- Date: 2024-04
- Subjects: Remote sensing , Geographic information systems , Groundwater flow
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/64322 , vital:73675
- Description: Assessing the spatio-temporal dynamics of land use land cover (LULC) change on hydrological response is vital for catchment sustainability and developing proper management strategies. The study aimed to assess the spatiotemporal effects and implications of LULC dynamics on surface runoff in the Luvuvhu River Catchment, Limpopo Province, using the Soil and Water Assessment Tool (SWAT) model. Satellite images of Landsat 5-thematic mapper and Landsat 8 operational land imager for the years 1990 and 2021 were used to explore the characteristics of LULC for this study by adopting the maximum likelihood (ML) supervised classification method. Five LULC classes were classified in this study; namely, water, built-up area, bare surface, dense vegetation, and sparse vegetation. The classification results show good accuracy values in the range of 76% (1990) and 84% (2021) with overall kappa of 63.8% and 72.8% for 1990 and 2021, respectively. For the purpose of this study, integration of geospatial technique and SWAT model were configured to operate at a monthly time interval over a span of 34 years, specifically from 1979 to 2013 to simulate surface runoff. The SWAT simulation process was executed using a digital elevation model, soil, LULC, and weather data. The analysis of LULC for 1990 and 2021 runoff modelling, it was found that, the runoff depth increased gradually from 3249 mm to 5162.5 mm during 1990 and 2021 LULC change, respectively. The R2, ENS, PBIAS, and RSR values for the calibration and the validation were 0.81 and 0.76, and 0.72 and 0.68, 0.64 and 0.58, 0.54 and 0.63 respectively. These values indicate good correlation between the observed and simulated stream flow data Therefore, suitable and timely management measures must be taken by policy decision-makers to enable sustainable development and to protect the catchment’s natural resources in order to reduce the severity of the changes. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2024
- Full Text:
- Date Issued: 2024-04
Relationship management in all-boys fee-paying public Schools in the Eastern Cape, South Africa: experiences and perspectives of LGBTQ alumni
- Authors: Mahlangu, Nhlakanipho
- Date: 2024-04
- Subjects: Single-sex schools -- South Africa -- Eastern Cape , Sex differences in education -- South Africa -- Eastern Cape , Customer relations -- Management , Sexual minorities -- Education -- Research -- South Africa -- Eastern Cape
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/65108 , vital:74024
- Description: This study explores the perspectives and experiences of LGBTQ alumni of all-boys’ schools in the Eastern Cape. The context of increased competition between schools in the education sector and the importance of inclusion within the sector necessitated a study to investigate the extent to which relationship management is conducted with an orientation towards LGBTQ inclusion in all-boys’ schools in the Eastern Cape. Student protests in South Africa over the past 10 years have expanded concerns about student belonging beyond the widely studied lenses of race and class. A growing body of literature and wider discourse emphasises student belonging as a challenge in the South African education sector. Marginalised students continue to experience educational spaces negatively. LGBTQ student experiences in the South Africa are characterised by violence and ostracisation, thus warranting further investigation and inquiry. The study locates itself in the intersections between gender and sexual diversity and economic citizenship in the broader discourse of school inclusivity. A qualitative research approach was employed, making use of semi-structured, in-depth individual interviews. The sample was derived from alumni of all-boys’ schools in the Eastern Cape through snowball sampling. Ten LGBTQ-identifying alumni of boys’ schools in the Eastern Cape were interviewed. The findings reveal the need to question the extent to which LGBTQ alumni can enjoy the fullness of the value proposition of all-boys’ schools, and what can be done to ensure LGBTQ belonging. The findings of this study concur with existing literature about LGBTQ experiences. Participants defined their school experiences as exclusionary and characterised by fear of failing to assert themselves in a hypermasculine school environment. LGBTQ alumni of all-boys’ schools in the Eastern Cape view relationship management as under-utilised as a tool to facilitate LGBTQ belonging. Instead, relationship management is used to affirm those who fit the mould of the quintessential ‘old boy’ network, by defining the masculine behaviours that learners in all-boys’ schools are compelled to aspire towards. , Thesis (MCom) -- Faculty of Business and Economic Sciences, School of Management Sciences, 2024
- Full Text:
- Date Issued: 2024-04
- Authors: Mahlangu, Nhlakanipho
- Date: 2024-04
- Subjects: Single-sex schools -- South Africa -- Eastern Cape , Sex differences in education -- South Africa -- Eastern Cape , Customer relations -- Management , Sexual minorities -- Education -- Research -- South Africa -- Eastern Cape
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/65108 , vital:74024
- Description: This study explores the perspectives and experiences of LGBTQ alumni of all-boys’ schools in the Eastern Cape. The context of increased competition between schools in the education sector and the importance of inclusion within the sector necessitated a study to investigate the extent to which relationship management is conducted with an orientation towards LGBTQ inclusion in all-boys’ schools in the Eastern Cape. Student protests in South Africa over the past 10 years have expanded concerns about student belonging beyond the widely studied lenses of race and class. A growing body of literature and wider discourse emphasises student belonging as a challenge in the South African education sector. Marginalised students continue to experience educational spaces negatively. LGBTQ student experiences in the South Africa are characterised by violence and ostracisation, thus warranting further investigation and inquiry. The study locates itself in the intersections between gender and sexual diversity and economic citizenship in the broader discourse of school inclusivity. A qualitative research approach was employed, making use of semi-structured, in-depth individual interviews. The sample was derived from alumni of all-boys’ schools in the Eastern Cape through snowball sampling. Ten LGBTQ-identifying alumni of boys’ schools in the Eastern Cape were interviewed. The findings reveal the need to question the extent to which LGBTQ alumni can enjoy the fullness of the value proposition of all-boys’ schools, and what can be done to ensure LGBTQ belonging. The findings of this study concur with existing literature about LGBTQ experiences. Participants defined their school experiences as exclusionary and characterised by fear of failing to assert themselves in a hypermasculine school environment. LGBTQ alumni of all-boys’ schools in the Eastern Cape view relationship management as under-utilised as a tool to facilitate LGBTQ belonging. Instead, relationship management is used to affirm those who fit the mould of the quintessential ‘old boy’ network, by defining the masculine behaviours that learners in all-boys’ schools are compelled to aspire towards. , Thesis (MCom) -- Faculty of Business and Economic Sciences, School of Management Sciences, 2024
- Full Text:
- Date Issued: 2024-04
Relationship Management in All-Boys’ Fee-paying Public Schools in the Eastern Cape, South Africa : Experiences and Perspectives of LGBTQ Alumni
- Authors: Mahlangu, Nhlakanipho
- Date: 2024-04
- Subjects: Gay men , Teenage boys , Public schools -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62237 , vital:72364
- Description: This study explores the perspectives and experiences of LGBTQ alumni of all-boys’ schools in the Eastern Cape. The context of increased competition between schools in the education sector and the importance of inclusion within the sector necessitated a study to investigate the extent to which relationship management is conducted with an orientation towards LGBTQ inclusion in all-boys’ schools in the Eastern Cape. Student protests in South Africa over the past 10 years have expanded concerns about student belonging beyond the widely studied lenses of race and class. A growing body of literature and wider discourse emphasises student belonging as a challenge in the South African education sector. Marginalised students continue to experience educational spaces negatively. LGBTQ student experiences in the South Africa are characterised by violence and ostracisation, thus warranting further investigation and inquiry. The study locates itself in the intersections between gender and sexual diversity and economic citizenship in the broader discourse of school inclusivity. A qualitative research approach was employed, making use of semi-structured, in-depth individual interviews. The sample was derived from alumni of all-boys’ schools in the Eastern Cape through snowball sampling. Ten LGBTQ-identifying alumni of boys’ schools in the Eastern Cape were interviewed. The findings reveal the need to question the extent to which LGBTQ alumni can enjoy the fullness of the value proposition of all-boys’ schools, and what can be done to ensure LGBTQ belonging. The findings of this study concur with existing literature about LGBTQ experiences. Participants defined their school experiences as exclusionary and characterised by fear of failing to assert themselves in a hypermasculine school environment. LGBTQ alumni of all-boys’ schools in the Eastern Cape view relationship management as under-utilised as a tool to facilitate LGBTQ belonging. Instead, relationship management is used to affirm those who fit the mould of the quintessential ‘old boy’ network, by defining the masculine behaviours that learners in all-boys’ schools are compelled to aspire towards. v ABSTRACT The findings illustrate that the culture of silence around non-confirming sexuality is sustained in the post-schooling relationship management life-cycle and results in the absence of the LGBTQ customer voice in the drafting of school strategy and policy. LGBTQ alumni who speak out about controversial issues often face admonition from their former teachers and peers. LGBTQ alumni criticise the relationship management of their former schools for the over-emphasis on fundraising and the complete absence of discussions on diversity. LGBTQ alumni are therefore marginalised in the process of value co-creation, as LGBTQ alumni feel they will never be viewed as legitimate collaborators by their former schools. The suggested recommendations emerging from this study include the need to codify school policies that speak specifically to LGBTQ marginalisation. Furthermore, schools must endeavour to make specific enquiries into LGBTQ student experiences and include LGBTQ concerns in wider school discourse. , Thesis (Ma) -- Faculty of Business and Economic Sciences, 2024
- Full Text:
- Date Issued: 2024-04
- Authors: Mahlangu, Nhlakanipho
- Date: 2024-04
- Subjects: Gay men , Teenage boys , Public schools -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62237 , vital:72364
- Description: This study explores the perspectives and experiences of LGBTQ alumni of all-boys’ schools in the Eastern Cape. The context of increased competition between schools in the education sector and the importance of inclusion within the sector necessitated a study to investigate the extent to which relationship management is conducted with an orientation towards LGBTQ inclusion in all-boys’ schools in the Eastern Cape. Student protests in South Africa over the past 10 years have expanded concerns about student belonging beyond the widely studied lenses of race and class. A growing body of literature and wider discourse emphasises student belonging as a challenge in the South African education sector. Marginalised students continue to experience educational spaces negatively. LGBTQ student experiences in the South Africa are characterised by violence and ostracisation, thus warranting further investigation and inquiry. The study locates itself in the intersections between gender and sexual diversity and economic citizenship in the broader discourse of school inclusivity. A qualitative research approach was employed, making use of semi-structured, in-depth individual interviews. The sample was derived from alumni of all-boys’ schools in the Eastern Cape through snowball sampling. Ten LGBTQ-identifying alumni of boys’ schools in the Eastern Cape were interviewed. The findings reveal the need to question the extent to which LGBTQ alumni can enjoy the fullness of the value proposition of all-boys’ schools, and what can be done to ensure LGBTQ belonging. The findings of this study concur with existing literature about LGBTQ experiences. Participants defined their school experiences as exclusionary and characterised by fear of failing to assert themselves in a hypermasculine school environment. LGBTQ alumni of all-boys’ schools in the Eastern Cape view relationship management as under-utilised as a tool to facilitate LGBTQ belonging. Instead, relationship management is used to affirm those who fit the mould of the quintessential ‘old boy’ network, by defining the masculine behaviours that learners in all-boys’ schools are compelled to aspire towards. v ABSTRACT The findings illustrate that the culture of silence around non-confirming sexuality is sustained in the post-schooling relationship management life-cycle and results in the absence of the LGBTQ customer voice in the drafting of school strategy and policy. LGBTQ alumni who speak out about controversial issues often face admonition from their former teachers and peers. LGBTQ alumni criticise the relationship management of their former schools for the over-emphasis on fundraising and the complete absence of discussions on diversity. LGBTQ alumni are therefore marginalised in the process of value co-creation, as LGBTQ alumni feel they will never be viewed as legitimate collaborators by their former schools. The suggested recommendations emerging from this study include the need to codify school policies that speak specifically to LGBTQ marginalisation. Furthermore, schools must endeavour to make specific enquiries into LGBTQ student experiences and include LGBTQ concerns in wider school discourse. , Thesis (Ma) -- Faculty of Business and Economic Sciences, 2024
- Full Text:
- Date Issued: 2024-04
Role of community pharmacies in the management of diabetic foot ulcers in South Africa
- Authors: Greyling, Cosette
- Date: 2024-04
- Subjects: Foot -- Ulcers -- Treatment , Wounds and injuries -- Treatment , Diabetes -- Complications
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63846 , vital:73619
- Description: Appropriate wound care and management are essential to prevent complications in patients with diabetic foot ulcers (DFUs). It is important to evaluate if patients are getting the necessary therapeutic treatment and counselling at community pharmacies. The primary aim was to determine the role of community pharmacies in South Africa in the management of DFUs. This study used a mixed-method research design combining both quantitative and qualitative research methodologies. In 2023 a questionnaire was distributed to a sample of 823 community pharmacists in South Africa with questions regarding DFUs. Data from the questionnaire were analysed and used in the next phase of the study, which was focus group discussions (FGDs). The FGDs were conducted with a group of pharmacy stakeholders. The response rate for the questionnaire was 18.95% (n=156). Only 105 respondents completed the questionnaire. Majority of the respondents (n=45) were located in Gauteng province, practising in corporate pharmacies (n=88) in urban areas (n=104). Majority of respondents (n=73) indicated that they did not have a clinic inside their pharmacies and 46 respondents indicated that they had a nurse employed in the pharmacy. Most frequently seen chronic wounds in community pharmacies were diabetic wounds and surgical wounds. Majority (n=71) of respondents indicated that they have not attended additional training on DFUs. Respondents indicated that they most often used the internet and other healthcare providers as information resources regarding DFUs. The results also indicated that community pharmacists would like to have more training regarding advanced wound care and that pharmacists do have a role to play when managing DFUs. During two FGDs, two main themes emerged namely “Community pharmacists encounter various challenges when treating patients with DFUs” and “There is a gap in training for community pharmacists in treating DFUs”. The focus group discussion (FGD) results complemented the questionnaire survey results. Since there is limited research published in South Africa on the role of community pharmacies managing DFUs, this study indicated that there is a need for additional training on DFUs for pharmacists working in community pharmacies in South Africa. , Thesis (M.Pharm) -- Faculty of Health Science, School of Clinical Care & Medicinal Sciences, 2024
- Full Text:
- Date Issued: 2024-04
- Authors: Greyling, Cosette
- Date: 2024-04
- Subjects: Foot -- Ulcers -- Treatment , Wounds and injuries -- Treatment , Diabetes -- Complications
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63846 , vital:73619
- Description: Appropriate wound care and management are essential to prevent complications in patients with diabetic foot ulcers (DFUs). It is important to evaluate if patients are getting the necessary therapeutic treatment and counselling at community pharmacies. The primary aim was to determine the role of community pharmacies in South Africa in the management of DFUs. This study used a mixed-method research design combining both quantitative and qualitative research methodologies. In 2023 a questionnaire was distributed to a sample of 823 community pharmacists in South Africa with questions regarding DFUs. Data from the questionnaire were analysed and used in the next phase of the study, which was focus group discussions (FGDs). The FGDs were conducted with a group of pharmacy stakeholders. The response rate for the questionnaire was 18.95% (n=156). Only 105 respondents completed the questionnaire. Majority of the respondents (n=45) were located in Gauteng province, practising in corporate pharmacies (n=88) in urban areas (n=104). Majority of respondents (n=73) indicated that they did not have a clinic inside their pharmacies and 46 respondents indicated that they had a nurse employed in the pharmacy. Most frequently seen chronic wounds in community pharmacies were diabetic wounds and surgical wounds. Majority (n=71) of respondents indicated that they have not attended additional training on DFUs. Respondents indicated that they most often used the internet and other healthcare providers as information resources regarding DFUs. The results also indicated that community pharmacists would like to have more training regarding advanced wound care and that pharmacists do have a role to play when managing DFUs. During two FGDs, two main themes emerged namely “Community pharmacists encounter various challenges when treating patients with DFUs” and “There is a gap in training for community pharmacists in treating DFUs”. The focus group discussion (FGD) results complemented the questionnaire survey results. Since there is limited research published in South Africa on the role of community pharmacies managing DFUs, this study indicated that there is a need for additional training on DFUs for pharmacists working in community pharmacies in South Africa. , Thesis (M.Pharm) -- Faculty of Health Science, School of Clinical Care & Medicinal Sciences, 2024
- Full Text:
- Date Issued: 2024-04
Rural teachers’ experiences during covid-19 pandemic: lessons learnt to cope with future emergencies
- Authors: Dlambewu, Amanda
- Date: 2024-04
- Subjects: COVID-19 (Disease) -- Social aspects -- South Africa , Rural schools -- South Africa , Teachers -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63945 , vital:73629
- Description: This study focused on challenges faced by rural teachers during the COVID-19 pandemic, with the intention of using the outcomes to develop a framework that could assist with coping with similar challenges in future emergencies. The study was situated in the interpretivist paradigm. A qualitative approach was employed using interviews and a focus group discussion. Bronfenbrenner’s ecological theory and the theory of rurality were used as lenses to explore and interpret the challenges that rural teachers experienced during the COVID-19 pandemic. The study's findings reveal that teachers faced the following challenges: mental health, adaptability, impact on personal life, safety, and work environment challenges. Furthermore, the study also found that teachers used the following coping mechanisms to deal with the challenges during the pandemic: adherence to rules and regulations, pastoral services, support from friends and family, collaboration, and physical activity. Finally, after applying both the theory of rurality and Bronfenbrenner's ecological theory to the findings, a framework was developed to assist in coping with future emergencies. , Thesis (MEd) -- Faculty of Education, Post Graduate Education, 2024
- Full Text:
- Date Issued: 2024-04
Rural teachers’ experiences during covid-19 pandemic: lessons learnt to cope with future emergencies
- Authors: Dlambewu, Amanda
- Date: 2024-04
- Subjects: COVID-19 (Disease) -- Social aspects -- South Africa , Rural schools -- South Africa , Teachers -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63945 , vital:73629
- Description: This study focused on challenges faced by rural teachers during the COVID-19 pandemic, with the intention of using the outcomes to develop a framework that could assist with coping with similar challenges in future emergencies. The study was situated in the interpretivist paradigm. A qualitative approach was employed using interviews and a focus group discussion. Bronfenbrenner’s ecological theory and the theory of rurality were used as lenses to explore and interpret the challenges that rural teachers experienced during the COVID-19 pandemic. The study's findings reveal that teachers faced the following challenges: mental health, adaptability, impact on personal life, safety, and work environment challenges. Furthermore, the study also found that teachers used the following coping mechanisms to deal with the challenges during the pandemic: adherence to rules and regulations, pastoral services, support from friends and family, collaboration, and physical activity. Finally, after applying both the theory of rurality and Bronfenbrenner's ecological theory to the findings, a framework was developed to assist in coping with future emergencies. , Thesis (MEd) -- Faculty of Education, Post Graduate Education, 2024
- Full Text:
- Date Issued: 2024-04
Seagrasses in Mozambique: distribution, people’s perceptions and restoration best practice
- Mabuto, Manuela Elisa Manuel Amone, Hollander, Johan
- Authors: Mabuto, Manuela Elisa Manuel Amone , Hollander, Johan
- Date: 2024-04
- Subjects: Seagrasses -- Mozambique , Seagrasses -- Southern Hemisphere , Coastal zone management -- Mozambique , Restoration ecology -- Mozambique
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/64126 , vital:73655
- Description: This thesis investigated the restoration of seagrass meadows and their associated biodiversity thus contributing to their conservation and to people's well-being. A mixed methods approach was used, and results presented in five chapters. Chapter I is a general introduction to the study outlining relevant information, research objectives and hypotheses. Chapter II investigates coastal community’s perceptions on the role of seagrass ecosystems, local impacts of coastal erosion and the need for seagrass restoration in Mozambique. It showed that there is a high awareness of the studied communities to seagrass importance for their livelihoods. Communities supported restoration and identified community engagement as a fundamental component for a successful implementation of restoration projects in their area. Chapter III conducted a mapping inventory for seagrass using open access data sources and investigated change detection in seagrass extent in southern Mozambique using Satellite imagery. In addition, Unmanned Aerial Vehicles (drones) were used to map seagrass to the species level at Inhaca Island. The results showed that seagrass habitats have been losing extent in recent years mainly in Bairro dos Pescadores at northwest Maputo Bay, due to sedimentation from flooding and inappropriate gleaning / clam collection practices. Around Inhaca Island seagrass extent has changed in response to natural causes and from anthropogenic disturbance near the main village and port area. For the first time for this area drones were used to rapidly and effectively acquire high- resolution data for detailed seagrass mapping and monitoring. The different mapping approaches were critically analyzed, and a way forward discussed. In Chapter IV, two different field experiments were conducted simultaneously. One, mimicked disturbance of meadows in terms of digging to collect clams, a common practice in northeastern Maputo Bay to assess the time of natural recovery and another replanted Zostera capensis using different plug sizes. The results indicated that once anthropogenic impacts are ceased, Z. capensis meadows are restored 12 months after impact exclusion. There was a 75% survival rate for the mechanical plug restoration approach; positive implications for seagrass transplantation projects that are both time consuming and financially costly. It was clear from the study that a combination of both impact exclusion and active restoration is needed for seagrass survival. Chapter V investigated the influence of seagrass restoration on the abundance and diversity of macroinvertebrates. After two years of observations, replanted seagrass areas had not recovered compared to natural established seagrass beds. However, a strong linear relationship existed between the abundance of seagrasses and the quantity of associated macrofauna species. Chapter VI provided recommendations on better ways to perform seagrass restoration and management. The main findings of this thesis provide new knowledge on the mapping of seagrass on a local to a regional scale as well as on better restoration practice of the seagrass Zostera capensis, an IUCN Red List vulnerable species. Communities’ perceptions on seagrass were investigated contributing to an understanding of the socio-ecological conservation and management of these critical and yet threatened ecosystems. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2024
- Full Text:
- Date Issued: 2024-04
- Authors: Mabuto, Manuela Elisa Manuel Amone , Hollander, Johan
- Date: 2024-04
- Subjects: Seagrasses -- Mozambique , Seagrasses -- Southern Hemisphere , Coastal zone management -- Mozambique , Restoration ecology -- Mozambique
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/64126 , vital:73655
- Description: This thesis investigated the restoration of seagrass meadows and their associated biodiversity thus contributing to their conservation and to people's well-being. A mixed methods approach was used, and results presented in five chapters. Chapter I is a general introduction to the study outlining relevant information, research objectives and hypotheses. Chapter II investigates coastal community’s perceptions on the role of seagrass ecosystems, local impacts of coastal erosion and the need for seagrass restoration in Mozambique. It showed that there is a high awareness of the studied communities to seagrass importance for their livelihoods. Communities supported restoration and identified community engagement as a fundamental component for a successful implementation of restoration projects in their area. Chapter III conducted a mapping inventory for seagrass using open access data sources and investigated change detection in seagrass extent in southern Mozambique using Satellite imagery. In addition, Unmanned Aerial Vehicles (drones) were used to map seagrass to the species level at Inhaca Island. The results showed that seagrass habitats have been losing extent in recent years mainly in Bairro dos Pescadores at northwest Maputo Bay, due to sedimentation from flooding and inappropriate gleaning / clam collection practices. Around Inhaca Island seagrass extent has changed in response to natural causes and from anthropogenic disturbance near the main village and port area. For the first time for this area drones were used to rapidly and effectively acquire high- resolution data for detailed seagrass mapping and monitoring. The different mapping approaches were critically analyzed, and a way forward discussed. In Chapter IV, two different field experiments were conducted simultaneously. One, mimicked disturbance of meadows in terms of digging to collect clams, a common practice in northeastern Maputo Bay to assess the time of natural recovery and another replanted Zostera capensis using different plug sizes. The results indicated that once anthropogenic impacts are ceased, Z. capensis meadows are restored 12 months after impact exclusion. There was a 75% survival rate for the mechanical plug restoration approach; positive implications for seagrass transplantation projects that are both time consuming and financially costly. It was clear from the study that a combination of both impact exclusion and active restoration is needed for seagrass survival. Chapter V investigated the influence of seagrass restoration on the abundance and diversity of macroinvertebrates. After two years of observations, replanted seagrass areas had not recovered compared to natural established seagrass beds. However, a strong linear relationship existed between the abundance of seagrasses and the quantity of associated macrofauna species. Chapter VI provided recommendations on better ways to perform seagrass restoration and management. The main findings of this thesis provide new knowledge on the mapping of seagrass on a local to a regional scale as well as on better restoration practice of the seagrass Zostera capensis, an IUCN Red List vulnerable species. Communities’ perceptions on seagrass were investigated contributing to an understanding of the socio-ecological conservation and management of these critical and yet threatened ecosystems. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2024
- Full Text:
- Date Issued: 2024-04
Self-attentive vision in evolutionary robotics
- Authors: Botha, Bouwer
- Date: 2024-04
- Subjects: Evolutionary robotics , Robotics , Neural networks (Computer science)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63628 , vital:73566
- Description: The autonomy of a robot refers to its ability to achieve a task in an environment with minimal human supervision. This may require autonomous solutions to be able to perceive their environment to inform their decisions. An inexpensive and highly informative way that robots can perceive the environment is through vision. The autonomy of a robot is reliant on the quality of the robotic controller. These controllers are the software interface between the robot and environment that determine the actions of the robot based on the perceived environment. Controllers are typically created using manual programming techniques, which become progressively more challenging with increasing complexity of both the robot and task. An alternative to manual programming is the use of machine learning techniques such as those used by Evolutionary Robotics (ER). ER is an area of research that investigates the automatic creation of controllers. Instead of manually programming a controller, an Evolutionary Algorithms can be used to evolve the controller through repeated interactions with the task environment. Employing the ER approach on camera-based controllers, however, has presented problems for conventional ER methods. Firstly, existing architectures that are capable of automatically processing images, have a large number of trained parameters. These architectures over-encumber the evolutionary process due to the large search space of possible configurations. Secondly, the evolution of complex controllers needs to be done in simulation, which requires either: (a) the construction of a photo-realistic virtual environment with accurate lighting, texturing and models or (b) potential reduction of the controller capability by simplifying the problem via image preprocessing. Any controller trained in simulation also raises the inherent concern of not being able to transfer to the real world. This study proposes a new technique for the evolution of camera-based controllers in ER, that aims to address the highlighted problems. The use of self-attention is proposed to facilitate the evolution of compact controllers that are able to evolve specialized sets of task-relevant features in unprocessed images by focussing on important image regions. Furthermore, a new neural network-based simulation approach, Generative Neuro-Augmented Vision (GNAV), is proposed to simplify simulation construction. GNAV makes use of random data collected in a simple virtual environment and the real world. A neural network is trained to overcome the visual discrepancies between these two environments. GNAV enables a controller to be trained in a simple simulated environment that appears similar to the real environment, while requiring minimal human supervision. The capabilities of the new technique were demonstrated using a series of real-world navigation tasks based on camera vision. Controllers utilizing the proposed self-attention mechanism were trained using GNAV and transferred to a real camera-equipped robot. The controllers were shown to be able to perform the same tasks in the real world. , Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2024
- Full Text:
- Date Issued: 2024-04
- Authors: Botha, Bouwer
- Date: 2024-04
- Subjects: Evolutionary robotics , Robotics , Neural networks (Computer science)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63628 , vital:73566
- Description: The autonomy of a robot refers to its ability to achieve a task in an environment with minimal human supervision. This may require autonomous solutions to be able to perceive their environment to inform their decisions. An inexpensive and highly informative way that robots can perceive the environment is through vision. The autonomy of a robot is reliant on the quality of the robotic controller. These controllers are the software interface between the robot and environment that determine the actions of the robot based on the perceived environment. Controllers are typically created using manual programming techniques, which become progressively more challenging with increasing complexity of both the robot and task. An alternative to manual programming is the use of machine learning techniques such as those used by Evolutionary Robotics (ER). ER is an area of research that investigates the automatic creation of controllers. Instead of manually programming a controller, an Evolutionary Algorithms can be used to evolve the controller through repeated interactions with the task environment. Employing the ER approach on camera-based controllers, however, has presented problems for conventional ER methods. Firstly, existing architectures that are capable of automatically processing images, have a large number of trained parameters. These architectures over-encumber the evolutionary process due to the large search space of possible configurations. Secondly, the evolution of complex controllers needs to be done in simulation, which requires either: (a) the construction of a photo-realistic virtual environment with accurate lighting, texturing and models or (b) potential reduction of the controller capability by simplifying the problem via image preprocessing. Any controller trained in simulation also raises the inherent concern of not being able to transfer to the real world. This study proposes a new technique for the evolution of camera-based controllers in ER, that aims to address the highlighted problems. The use of self-attention is proposed to facilitate the evolution of compact controllers that are able to evolve specialized sets of task-relevant features in unprocessed images by focussing on important image regions. Furthermore, a new neural network-based simulation approach, Generative Neuro-Augmented Vision (GNAV), is proposed to simplify simulation construction. GNAV makes use of random data collected in a simple virtual environment and the real world. A neural network is trained to overcome the visual discrepancies between these two environments. GNAV enables a controller to be trained in a simple simulated environment that appears similar to the real environment, while requiring minimal human supervision. The capabilities of the new technique were demonstrated using a series of real-world navigation tasks based on camera vision. Controllers utilizing the proposed self-attention mechanism were trained using GNAV and transferred to a real camera-equipped robot. The controllers were shown to be able to perform the same tasks in the real world. , Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2024
- Full Text:
- Date Issued: 2024-04
South Africa’s regulation of mineral mining activities in the area: lessons from the United Kingdom
- Authors: Karomo, Adelaide Aquiline
- Date: 2024-04
- Subjects: Mineral mining activities , Mining law , Deep Sea mining Act
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/64411 , vital:73700
- Description: As they anticipate the benefits associated with mining polymetallic nodules, polymetallic sulphides and ferromanganese crusts, several States are currently exploring or sponsoring State-owned enterprises and private persons to explore for these mineral resources in the seabed, ocean floor and subsoil beyond national jurisdiction (the Area). However, Africa remains the only region that is not actively participating. To guide South Africa in developing a deep seabed mining regime the thesis begins by identifying the international law regulating the Area and the activities therein. Since the mineral resources in the Area have been declared the common heritage of mankind, this principle as regulated by Part XI of the United Nations Convention on the Law of the Sea (UNCLOS), and modified by the Agreement relating to the implementation of Part XI of the United Nations Convention on the Law of the Sea of 10 December 1982 forms an essential component of this study. As such, the thesis determines, amongst others, the requirements for participating in mining activities in the Area (as set out in Part XI of UNCLOS) and establishes that developing a legislative framework is crucial to exempt UNCLOS States parties from liability associated with the damage caused by sponsored activities. Based on the obligations in international law, the thesis zooms in on three aspects concerning the regulation of the activities in the Area: (i) mining concessions, (ii) the relevant payment system, and (iii) environmental protection measures. In terms of these aspects, how the United Kingdom’s deep seabed mining regime regulates activities in the Area is examined. For this assessment, the thesis pays particular attention to the Deep Sea Mining Act and the domestic licences granted to UK Seabed Resources Ltd (UKSRL). In identifying lessons for South Africa, the thesis assesses the extent to which the United Kingdom’s regime complies with the international law framework and highlights the inconsistencies and legislative gaps. Thereafter, the thesis examines the South African legislative instruments regulating mining activities at sea, such as the Mineral and Petroleum Resources Development Act and the National Environmental Management Act, to determine whether their scope should be amended to regulate mining activities in the Area. As per the observations from international law and the lessons learnt from the United Kingdom's regulatory framework, the thesis argues that South Africa’s current mining framework should not be amended; separate deep seabed mining-specific legislation must be adopted. The thesis concludes by setting out the recommendations for developing such legislation. , Thesis (LLD) -- Faculty of Law, 2024
- Full Text:
- Date Issued: 2024-04
- Authors: Karomo, Adelaide Aquiline
- Date: 2024-04
- Subjects: Mineral mining activities , Mining law , Deep Sea mining Act
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/64411 , vital:73700
- Description: As they anticipate the benefits associated with mining polymetallic nodules, polymetallic sulphides and ferromanganese crusts, several States are currently exploring or sponsoring State-owned enterprises and private persons to explore for these mineral resources in the seabed, ocean floor and subsoil beyond national jurisdiction (the Area). However, Africa remains the only region that is not actively participating. To guide South Africa in developing a deep seabed mining regime the thesis begins by identifying the international law regulating the Area and the activities therein. Since the mineral resources in the Area have been declared the common heritage of mankind, this principle as regulated by Part XI of the United Nations Convention on the Law of the Sea (UNCLOS), and modified by the Agreement relating to the implementation of Part XI of the United Nations Convention on the Law of the Sea of 10 December 1982 forms an essential component of this study. As such, the thesis determines, amongst others, the requirements for participating in mining activities in the Area (as set out in Part XI of UNCLOS) and establishes that developing a legislative framework is crucial to exempt UNCLOS States parties from liability associated with the damage caused by sponsored activities. Based on the obligations in international law, the thesis zooms in on three aspects concerning the regulation of the activities in the Area: (i) mining concessions, (ii) the relevant payment system, and (iii) environmental protection measures. In terms of these aspects, how the United Kingdom’s deep seabed mining regime regulates activities in the Area is examined. For this assessment, the thesis pays particular attention to the Deep Sea Mining Act and the domestic licences granted to UK Seabed Resources Ltd (UKSRL). In identifying lessons for South Africa, the thesis assesses the extent to which the United Kingdom’s regime complies with the international law framework and highlights the inconsistencies and legislative gaps. Thereafter, the thesis examines the South African legislative instruments regulating mining activities at sea, such as the Mineral and Petroleum Resources Development Act and the National Environmental Management Act, to determine whether their scope should be amended to regulate mining activities in the Area. As per the observations from international law and the lessons learnt from the United Kingdom's regulatory framework, the thesis argues that South Africa’s current mining framework should not be amended; separate deep seabed mining-specific legislation must be adopted. The thesis concludes by setting out the recommendations for developing such legislation. , Thesis (LLD) -- Faculty of Law, 2024
- Full Text:
- Date Issued: 2024-04
Spatiotemporal recharge determination in response to episodic rainfall events within the Central Karoo, South Africa
- Authors: Williams, Aarifah
- Date: 2024-04
- Subjects: Groundwater -- South Africa -- Beaufort West , Groundwater recharge , Hydrogeology
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/64459 , vital:73735
- Description: With inadequate and unpredictable rainfall patterns resulting in a mean annual precipitation of 464 mm, South Africa is classified as a water-stressed semi-arid country. Consequently, between 2015 and 2021, the majority of South Africa was confronted with severe drought conditions, with numerous dams running dry across the country. The Beaufort West Municipality is a prime example of the adverse effects of South Africa's inadequate and erratic rainfall patterns. In Beaufort West, a town located within the Central Karoo region of the Western Cape, groundwater is the primary source of water. Since recharge within the region is episodic, occurring irregularly, understanding the dynamics surrounding recharge in the area is essential for achieving sustainable long-term water resource management. This study aimed to gain a better understanding of how the aquifers within the Beaufort West Municipality Well Fields respond to extended periods of drought, extreme episodic precipitation events and excessive abstraction. This study aimed to quantify extreme recharge in the Beaufort West municipal wellfields using the water-table fluctuation (WTF) method. Additionally, it sought to deepen comprehension of the local climate's interaction with groundwater levels, surface water dynamics, and recharge through a 32-year historical data analysis (1990 to 2022) encompassing precipitation, evaporation, and surface water parameters. Findings revealed the complex relationship between precipitation, evaporation, regional geology, and water abstraction, influencing recharge periods, duration, and mechanisms across different regions within the aquifer system. Groundwater levels exhibited rapid declines during droughts due to extensive well field abstraction, but recovery was evident following episodic high precipitation events in 1993, 1996, 2010/2011, and 2019/2020. This comprehensive analysis serves as a valuable foundation for informed water resource management strategies, emphasizing the need for diversified approaches ensure the long-term water security and resilience of the Beaufort West Municipality. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2024
- Full Text:
- Date Issued: 2024-04
- Authors: Williams, Aarifah
- Date: 2024-04
- Subjects: Groundwater -- South Africa -- Beaufort West , Groundwater recharge , Hydrogeology
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/64459 , vital:73735
- Description: With inadequate and unpredictable rainfall patterns resulting in a mean annual precipitation of 464 mm, South Africa is classified as a water-stressed semi-arid country. Consequently, between 2015 and 2021, the majority of South Africa was confronted with severe drought conditions, with numerous dams running dry across the country. The Beaufort West Municipality is a prime example of the adverse effects of South Africa's inadequate and erratic rainfall patterns. In Beaufort West, a town located within the Central Karoo region of the Western Cape, groundwater is the primary source of water. Since recharge within the region is episodic, occurring irregularly, understanding the dynamics surrounding recharge in the area is essential for achieving sustainable long-term water resource management. This study aimed to gain a better understanding of how the aquifers within the Beaufort West Municipality Well Fields respond to extended periods of drought, extreme episodic precipitation events and excessive abstraction. This study aimed to quantify extreme recharge in the Beaufort West municipal wellfields using the water-table fluctuation (WTF) method. Additionally, it sought to deepen comprehension of the local climate's interaction with groundwater levels, surface water dynamics, and recharge through a 32-year historical data analysis (1990 to 2022) encompassing precipitation, evaporation, and surface water parameters. Findings revealed the complex relationship between precipitation, evaporation, regional geology, and water abstraction, influencing recharge periods, duration, and mechanisms across different regions within the aquifer system. Groundwater levels exhibited rapid declines during droughts due to extensive well field abstraction, but recovery was evident following episodic high precipitation events in 1993, 1996, 2010/2011, and 2019/2020. This comprehensive analysis serves as a valuable foundation for informed water resource management strategies, emphasizing the need for diversified approaches ensure the long-term water security and resilience of the Beaufort West Municipality. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2024
- Full Text:
- Date Issued: 2024-04
Statutory conciliation as a labour-dispute-resolution mechanism
- Authors: Masaya, Ruvimbo Cheryl
- Date: 2024-04
- Subjects: Labor disputes -- South Africa , South Africa. -- Labour Relations Act, 1995 , Labor -- Law and legislation -- South Africa , Industrial relations -- South Africa South Africa. -- Commission for Conciliation, Mediation, and Arbitration
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/65701 , vital:74229
- Description: South African labour dispute resolution is a product of the country’s problematic past which was based on inequality and division. The new political dispensation led to the adoption of the Constitution of the Republic of South Africa in 1996, which enshrined a variety of basic human rights for all people within the Republic. Amongst these rights was section 23, which provided for and still protects the right to fair labour practices for all. In order to further give effect to this right, the Labour Relations Act was promulgated, with section 112 of the Act establishing the Commission for Conciliation, Mediation and Arbitration (hereafter referred to as the CCMA). One of the main mandatory functions of the CCMA is that of statutory conciliation. Statutory conciliation must also be performed by any other accredited bodies such as bargaining councils. The term statutory conciliation refers to a process that occurs under the direction of an impartial third party where parties to a dispute endeavour to reach an agreement in order to settle the dispute. The process is without prejudice and proceedings are intended to help the parties find an amicable solution. It can be a very powerful tool to settle disputes in the labour law context where there are disputes between employers and employees where internal procedures have been exhausted and a deadlock has been reached. Statutory conciliation is the first step where a case has been referred to the CCMA. According to the CCMA, 3 844 169 cases have been referred to it since its establishment in 1996.1 In the 2021/22 financial year thus far, the number of case referrals to the CCMA sits at 156 777, a reflection of how well utilised the mechanism is. The main aim of this treatise is to explore the role of statutory conciliation as a mechanism of labour dispute resolution. The history and development of labour dispute resolution in South Africa will be examined; briefly followed by an explanation of the process of conciliation. The treatise will also consider the limitations of the process of statutory conciliation, as the process is not immune to abuse by parties. Since the advent of the Labour Relations Act, the courts have had to consider various aspects of conciliation, in particular concerning the confidentiality of the process and whether a commissioner may be compelled to testify on the conciliation process at arbitration or the Labour Court. In addition, the ambit of the conciliation commissioner’s functions and powers will also be considered. , Thesis (LLM) -- Faculty of Law, Department of Mercantile law, 2024
- Full Text:
- Date Issued: 2024-04
- Authors: Masaya, Ruvimbo Cheryl
- Date: 2024-04
- Subjects: Labor disputes -- South Africa , South Africa. -- Labour Relations Act, 1995 , Labor -- Law and legislation -- South Africa , Industrial relations -- South Africa South Africa. -- Commission for Conciliation, Mediation, and Arbitration
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/65701 , vital:74229
- Description: South African labour dispute resolution is a product of the country’s problematic past which was based on inequality and division. The new political dispensation led to the adoption of the Constitution of the Republic of South Africa in 1996, which enshrined a variety of basic human rights for all people within the Republic. Amongst these rights was section 23, which provided for and still protects the right to fair labour practices for all. In order to further give effect to this right, the Labour Relations Act was promulgated, with section 112 of the Act establishing the Commission for Conciliation, Mediation and Arbitration (hereafter referred to as the CCMA). One of the main mandatory functions of the CCMA is that of statutory conciliation. Statutory conciliation must also be performed by any other accredited bodies such as bargaining councils. The term statutory conciliation refers to a process that occurs under the direction of an impartial third party where parties to a dispute endeavour to reach an agreement in order to settle the dispute. The process is without prejudice and proceedings are intended to help the parties find an amicable solution. It can be a very powerful tool to settle disputes in the labour law context where there are disputes between employers and employees where internal procedures have been exhausted and a deadlock has been reached. Statutory conciliation is the first step where a case has been referred to the CCMA. According to the CCMA, 3 844 169 cases have been referred to it since its establishment in 1996.1 In the 2021/22 financial year thus far, the number of case referrals to the CCMA sits at 156 777, a reflection of how well utilised the mechanism is. The main aim of this treatise is to explore the role of statutory conciliation as a mechanism of labour dispute resolution. The history and development of labour dispute resolution in South Africa will be examined; briefly followed by an explanation of the process of conciliation. The treatise will also consider the limitations of the process of statutory conciliation, as the process is not immune to abuse by parties. Since the advent of the Labour Relations Act, the courts have had to consider various aspects of conciliation, in particular concerning the confidentiality of the process and whether a commissioner may be compelled to testify on the conciliation process at arbitration or the Labour Court. In addition, the ambit of the conciliation commissioner’s functions and powers will also be considered. , Thesis (LLM) -- Faculty of Law, Department of Mercantile law, 2024
- Full Text:
- Date Issued: 2024-04
Sustainable management of the back sourcing of service functions at South African universities
- Authors: Hashatse, Lebogang
- Date: 2024-04
- Subjects: Contracting out -- South Africa , Education, Higher -- South Africa -- Economic aspects , Universities and colleges -- South Africa -- Economic aspects , Universities and colleges -- Management Universities and colleges -- South Africa -- Employees
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/64996 , vital:74004
- Description: This study employed a three-phase qualitative case study research method to determine whether backsourcing and reintegration of previously outsourced services and workers could be managed in ways that contributed to the long-term sustainability of institutions. To achieve this goal, the study developed a framework for the sustainable management of university-based resources. The framework was a response in support of institutional sustainability after South African public universities were compelled to implement involuntary backsourcing in response to the ongoing #FeesMustFall (#FMF) and #OutsourcingMustFall (#OMF) protests that commenced in the latter part of 2015. An extensive literature review was conducted as part of the study’s phase one. The goal was to obtain insight into management practises used in outsourcing and backsourcing as well as to gain a thorough grasp of the concept of sustainability and its application in resource management in the settings of operations, organisations and universities. The literature demonstrated that there were well-established theoretical frameworks supporting the concepts of backsourcing and sustainability management. These frameworks provided clear outlines of how successful backsourcing and remunicipalisation processes could be effectively managed. Moreover, they highlighted that these management processes could be used by profitable sustainable businesses. This contributed to the development of a theoretical framework for the study. A conceptual framework together with the outcome of the literature review, served as a guide for conducting a qualitative case study at a selected Higher Education Institution (HEI) in South Africa, which was chosen as the primary research site. This constituted phase two of the study. The selected HEI case study established its efficacy in managing the process of backsourcing and reintegration. Furthermore, it demonstrated sustainable ways that contributed to the institution’s overall sustainability. In conjunction with the established theoretical framework and the developed conceptual framework, the selected HEI , Thesis (PhD) -- Faculty of Business and Economic Sciences, School of Management Sciences, 2024
- Full Text:
- Date Issued: 2024-04
- Authors: Hashatse, Lebogang
- Date: 2024-04
- Subjects: Contracting out -- South Africa , Education, Higher -- South Africa -- Economic aspects , Universities and colleges -- South Africa -- Economic aspects , Universities and colleges -- Management Universities and colleges -- South Africa -- Employees
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/64996 , vital:74004
- Description: This study employed a three-phase qualitative case study research method to determine whether backsourcing and reintegration of previously outsourced services and workers could be managed in ways that contributed to the long-term sustainability of institutions. To achieve this goal, the study developed a framework for the sustainable management of university-based resources. The framework was a response in support of institutional sustainability after South African public universities were compelled to implement involuntary backsourcing in response to the ongoing #FeesMustFall (#FMF) and #OutsourcingMustFall (#OMF) protests that commenced in the latter part of 2015. An extensive literature review was conducted as part of the study’s phase one. The goal was to obtain insight into management practises used in outsourcing and backsourcing as well as to gain a thorough grasp of the concept of sustainability and its application in resource management in the settings of operations, organisations and universities. The literature demonstrated that there were well-established theoretical frameworks supporting the concepts of backsourcing and sustainability management. These frameworks provided clear outlines of how successful backsourcing and remunicipalisation processes could be effectively managed. Moreover, they highlighted that these management processes could be used by profitable sustainable businesses. This contributed to the development of a theoretical framework for the study. A conceptual framework together with the outcome of the literature review, served as a guide for conducting a qualitative case study at a selected Higher Education Institution (HEI) in South Africa, which was chosen as the primary research site. This constituted phase two of the study. The selected HEI case study established its efficacy in managing the process of backsourcing and reintegration. Furthermore, it demonstrated sustainable ways that contributed to the institution’s overall sustainability. In conjunction with the established theoretical framework and the developed conceptual framework, the selected HEI , Thesis (PhD) -- Faculty of Business and Economic Sciences, School of Management Sciences, 2024
- Full Text:
- Date Issued: 2024-04
Synthesis and applications of hydroxyl-functionalized chemosensors for selective detection of ions in aqueous systems
- Authors: Hamukoshi, Simeon Shiweda
- Date: 2024-04
- Subjects: Molecular recognition , Solution (Chemistry) , Water chemistry
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63787 , vital:73613
- Description: Fluorescent molecular chemosensors are crucial tools for monitoring toxic metal ions and environmental compounds that pose risks to both humans and wildlife. Continuous sensing is essential for early detection, and chemosensors offer a sensitive and straightforward approach by detecting challenging analyte’s through optical absorption and fluorescence. Current detection methods, such as flame photometry and mass spectrometry, can be expensive, destructive, and impractical for continuous monitoring. Consequently, fluorescent-based methods present a promising, simple, and highly sensitive alternative for chemical recognition and monitoring. In this project, we successfully synthesized ten highly selective small hydroxyl containing molecule fluorescent and colorimetric sensors; Oxime Dye (OD), Small Sensor 1 (SS1), Small Sensor 2 (SS2), Quinoline Dye 1 (QD1), Quinoline Dye 2 (QD2), Quinoline Dye 3 (QD3), Coumarin Dye 1 (CD1), Coumarin Dye 2 (CD2), Naphthalene Dye 1 (ND1), Naphthalene Dye 2 (ND2). These chemosensors contained benzothiazole, naphthalene, quinoline, and coumarin fluorophores. These sensors facilitate both quantitative and qualitative assessment of cationic and anionic species in aqueous organic media. The chemosensors were synthesized using modified Schiff base, azo dye, and oxime-based reactions, enhancing binding and selectivity with analyte’s. They exhibited selectivity towards various metal ions (Cu2+, Fe2+, Ni2+, and Hg2+) and anions (hydroxyl and cyanate), characterized by distinct absorption bands and significant fluorescent quenching and enhancement. While some sensors were selective towards both cations and anions, others exclusively targeted cations, showing lower selectivity or sensitivity towards anions upon further testing. Conversely, certain sensors were selective towards anions, demonstrating reduced sensitivity or selectivity towards the tested cations. The oxime-based chemosensor, OD, was obtained through an oxime-based reaction. The sensor demonstrates remarkable selectivity for Cu2+ and cyanate ions. During titration experiments, the interaction of Cu2+ with OD resulted in a noticeable fluorescence quenching effect, while the presence of OCN ions led to fluorescence enhancement. These distinct behaviors strongly suggest the formation of specific 1:1 complexes between OD and Cu2+ or OCN ions, a conclusion supported by detailed analysis using the Jobs plot technique. In addition to the fluorescence studies, investigations into the influence of pH on the sensor OD, as well as its complexes with Cu2+ and OCN, were conducted to determine the optimum pH conditions for their operation. Moreover, reversible behavior of the complexes was explored in the presence of EDTA, revealing that only the OD-OCN complex displayed reversibility. Furthermore, molecular modeling studies were performed to validate the binding units and calculate the energy differences between the sensor and its respective complexes. Additionally, four chemosensors (SS1, SS2, CD2, and QD2) were synthesized and characterized using Schiff-based reactions, showcasing their unique absorption behaviors. SS1 and SS2, characterized by benzothiazole fluorophores, demonstrated high sensitivity to hydroxyl anions. Jobs plot studies revealed a stable 1:1 binding stoichiometry. Chemosensor CD2, incorporating a coumarin fluorophore, was structurally confirmed but showed no significant spectral changes when screened with various ions. Chemosensor QD2 exhibited remarkable selectivity for Fe2+ ions, and stable 1:1 complexes were confirmed. Further molecular modeling studies were conducted to identify potential binding sites. Furthermore, five chemosensors (CD1, CD3, QD1, ND1, and ND2) were synthesized and characterized using azo dye reactions, revealing their unique absorption behaviors. Chemosensor CD1 showed high selectivity towards Hg2+ under both absorption and emission spectroscopy. Job's plot studies confirmed a stable 1:1 complex formation. The presence of competing cations did not affect complex formation, emphasizing its stability and selectivity. Another coumarin-containing dye chemosensor, CD3, was synthesized as a novel chemosensor. In the presence of TBA anionic solutions, CD3 exhibited strong absorption bands and selectivity for OH- ions, forming a stable complex with them. Quantitative studies, including the determination of LOD and LOQ, were also conducted. The binding stoichiometry of 1:1 between CD3 and OH- was established through Job's plot analysis. Lastly, two naphthalene dyes were synthesized. However, they did not exhibit selectivity towards cations or anions. Interestingly, their absorption spectra were affected by the change in solvent system, a concept worth exploring in future work. Chemosensor ND1 and ND2 did not show any cation or anion selectivity. However, they demonstrated different spectra and colour responses to cations and anions in different water-DMSO solvent systems. , Thesis (PhD) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 2024
- Full Text:
- Date Issued: 2024-04
- Authors: Hamukoshi, Simeon Shiweda
- Date: 2024-04
- Subjects: Molecular recognition , Solution (Chemistry) , Water chemistry
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63787 , vital:73613
- Description: Fluorescent molecular chemosensors are crucial tools for monitoring toxic metal ions and environmental compounds that pose risks to both humans and wildlife. Continuous sensing is essential for early detection, and chemosensors offer a sensitive and straightforward approach by detecting challenging analyte’s through optical absorption and fluorescence. Current detection methods, such as flame photometry and mass spectrometry, can be expensive, destructive, and impractical for continuous monitoring. Consequently, fluorescent-based methods present a promising, simple, and highly sensitive alternative for chemical recognition and monitoring. In this project, we successfully synthesized ten highly selective small hydroxyl containing molecule fluorescent and colorimetric sensors; Oxime Dye (OD), Small Sensor 1 (SS1), Small Sensor 2 (SS2), Quinoline Dye 1 (QD1), Quinoline Dye 2 (QD2), Quinoline Dye 3 (QD3), Coumarin Dye 1 (CD1), Coumarin Dye 2 (CD2), Naphthalene Dye 1 (ND1), Naphthalene Dye 2 (ND2). These chemosensors contained benzothiazole, naphthalene, quinoline, and coumarin fluorophores. These sensors facilitate both quantitative and qualitative assessment of cationic and anionic species in aqueous organic media. The chemosensors were synthesized using modified Schiff base, azo dye, and oxime-based reactions, enhancing binding and selectivity with analyte’s. They exhibited selectivity towards various metal ions (Cu2+, Fe2+, Ni2+, and Hg2+) and anions (hydroxyl and cyanate), characterized by distinct absorption bands and significant fluorescent quenching and enhancement. While some sensors were selective towards both cations and anions, others exclusively targeted cations, showing lower selectivity or sensitivity towards anions upon further testing. Conversely, certain sensors were selective towards anions, demonstrating reduced sensitivity or selectivity towards the tested cations. The oxime-based chemosensor, OD, was obtained through an oxime-based reaction. The sensor demonstrates remarkable selectivity for Cu2+ and cyanate ions. During titration experiments, the interaction of Cu2+ with OD resulted in a noticeable fluorescence quenching effect, while the presence of OCN ions led to fluorescence enhancement. These distinct behaviors strongly suggest the formation of specific 1:1 complexes between OD and Cu2+ or OCN ions, a conclusion supported by detailed analysis using the Jobs plot technique. In addition to the fluorescence studies, investigations into the influence of pH on the sensor OD, as well as its complexes with Cu2+ and OCN, were conducted to determine the optimum pH conditions for their operation. Moreover, reversible behavior of the complexes was explored in the presence of EDTA, revealing that only the OD-OCN complex displayed reversibility. Furthermore, molecular modeling studies were performed to validate the binding units and calculate the energy differences between the sensor and its respective complexes. Additionally, four chemosensors (SS1, SS2, CD2, and QD2) were synthesized and characterized using Schiff-based reactions, showcasing their unique absorption behaviors. SS1 and SS2, characterized by benzothiazole fluorophores, demonstrated high sensitivity to hydroxyl anions. Jobs plot studies revealed a stable 1:1 binding stoichiometry. Chemosensor CD2, incorporating a coumarin fluorophore, was structurally confirmed but showed no significant spectral changes when screened with various ions. Chemosensor QD2 exhibited remarkable selectivity for Fe2+ ions, and stable 1:1 complexes were confirmed. Further molecular modeling studies were conducted to identify potential binding sites. Furthermore, five chemosensors (CD1, CD3, QD1, ND1, and ND2) were synthesized and characterized using azo dye reactions, revealing their unique absorption behaviors. Chemosensor CD1 showed high selectivity towards Hg2+ under both absorption and emission spectroscopy. Job's plot studies confirmed a stable 1:1 complex formation. The presence of competing cations did not affect complex formation, emphasizing its stability and selectivity. Another coumarin-containing dye chemosensor, CD3, was synthesized as a novel chemosensor. In the presence of TBA anionic solutions, CD3 exhibited strong absorption bands and selectivity for OH- ions, forming a stable complex with them. Quantitative studies, including the determination of LOD and LOQ, were also conducted. The binding stoichiometry of 1:1 between CD3 and OH- was established through Job's plot analysis. Lastly, two naphthalene dyes were synthesized. However, they did not exhibit selectivity towards cations or anions. Interestingly, their absorption spectra were affected by the change in solvent system, a concept worth exploring in future work. Chemosensor ND1 and ND2 did not show any cation or anion selectivity. However, they demonstrated different spectra and colour responses to cations and anions in different water-DMSO solvent systems. , Thesis (PhD) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 2024
- Full Text:
- Date Issued: 2024-04