A case study assessment of the ecological and social status of the South African boat-based whale watching industry
- Authors: Tolsma, Minke
- Date: 2022-04
- Subjects: Whale watching --South Africa , Dolphin watching
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/55887 , vital:54397
- Description: Boat-based whale-watching (BBWW) is a rapidly growing marine tourism industry globally and in South Africa (SA). BBWW in SA was established in 1998, and since then the number of permits available has doubled from 20 to 40. However, the establishment and past growth of the industry was undertaken without ecological research or impact assessments. Global research has shown that BBWW has the potential to cause short-term changes in cetacean behaviour and movement, which in turn can have long-term population-level consequences. National policies to grow ocean economies in SA may encourage excessive growth in the BBWW industry, impacting the ecological sustainability. In the absence of long-term impact data, the BBWW industry should be managed to minimise short-term changes. This study aimed to determine the social and ecological status of the SA BBWW industry, using Plettenberg Bay as a case study, to inform its long term sustainability. To achieve this aim: 1) the short-term behavioural and movement responses of six cetacean species to encounters with commercial BBWW vessels were measured; 2) the efficacy of three permit regulations (approach speed, approach angle, and encounter duration) to prevent short-term behavioural changes in three cetacean species was measured; 3) rates of compliance of BBWWoperators with current regulations were recorded; 4) BBWW tourists’ expectations of and satisfaction with the industry were investigated; as well as 5) operators’ views on the current permit regulations of the industry All research was conducted between September 2018 and November 2020 in Plettenberg Bay (SA) where two BBWW companies operating two vessels each are active. Three dolphin (bottlenose, common and humpback dolphins) and three whale (Bryde’s, humpback and southern right whales) species are targeted by the industry, and were encountered during this study. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Tolsma, Minke
- Date: 2022-04
- Subjects: Whale watching --South Africa , Dolphin watching
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/55887 , vital:54397
- Description: Boat-based whale-watching (BBWW) is a rapidly growing marine tourism industry globally and in South Africa (SA). BBWW in SA was established in 1998, and since then the number of permits available has doubled from 20 to 40. However, the establishment and past growth of the industry was undertaken without ecological research or impact assessments. Global research has shown that BBWW has the potential to cause short-term changes in cetacean behaviour and movement, which in turn can have long-term population-level consequences. National policies to grow ocean economies in SA may encourage excessive growth in the BBWW industry, impacting the ecological sustainability. In the absence of long-term impact data, the BBWW industry should be managed to minimise short-term changes. This study aimed to determine the social and ecological status of the SA BBWW industry, using Plettenberg Bay as a case study, to inform its long term sustainability. To achieve this aim: 1) the short-term behavioural and movement responses of six cetacean species to encounters with commercial BBWW vessels were measured; 2) the efficacy of three permit regulations (approach speed, approach angle, and encounter duration) to prevent short-term behavioural changes in three cetacean species was measured; 3) rates of compliance of BBWWoperators with current regulations were recorded; 4) BBWW tourists’ expectations of and satisfaction with the industry were investigated; as well as 5) operators’ views on the current permit regulations of the industry All research was conducted between September 2018 and November 2020 in Plettenberg Bay (SA) where two BBWW companies operating two vessels each are active. Three dolphin (bottlenose, common and humpback dolphins) and three whale (Bryde’s, humpback and southern right whales) species are targeted by the industry, and were encountered during this study. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-04
A case study on the incidence and extent of medullated and coloured fibres in the commercially produced South African wool clip 2010 – 2017
- Authors: Zietsman, Jolandrie
- Date: 2022-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55445 , vital:52002
- Description: No formal study on the incidence and extent of medullated and coloured fibres has been performed in South Africa. The purpose of this research project was to investigate the validity of the claims that there has been an increase in the production of wool contaminated with medullated and coloured fibres. Therefore, the main aim of this study was to determine whether the incidence and extent of medullated and coloured fibres in the South African wool clip have changed over time. Secondly, the study aimed to determine whether the incidence and extent of medullated and coloured fibres have a distinct geographic distribution. This study explored eight years of wool production records (2010 to 2017) obtained from BKB, the largest wool broker in South Africa. For the purpose of this research, the wool-producing areas of South Africa were divided into 6 regions, according to average annual rainfall, vegetation type and major farming practices applied in the area. Statistical analysis of the data included descriptive statistics, analysis of variance and post-hoc tests, as well as regression analyses. This study succeeded in quantifying the extent and prevalence of contamination with medullated and coloured fibres in the South African wool clip. The overarching conclusions were: • Floating kemp is the most important contaminant of wool in South Africa, with the incidence of harsh kemp and coloured fibres being very low. • Generally, the most important areas that need attention in combatting contamination in the South African wool clip, are the Mixed Farming Summer Rainfall Region, the Semi-Arid Grassveld and the High Rainfall Grassland. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Zietsman, Jolandrie
- Date: 2022-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55445 , vital:52002
- Description: No formal study on the incidence and extent of medullated and coloured fibres has been performed in South Africa. The purpose of this research project was to investigate the validity of the claims that there has been an increase in the production of wool contaminated with medullated and coloured fibres. Therefore, the main aim of this study was to determine whether the incidence and extent of medullated and coloured fibres in the South African wool clip have changed over time. Secondly, the study aimed to determine whether the incidence and extent of medullated and coloured fibres have a distinct geographic distribution. This study explored eight years of wool production records (2010 to 2017) obtained from BKB, the largest wool broker in South Africa. For the purpose of this research, the wool-producing areas of South Africa were divided into 6 regions, according to average annual rainfall, vegetation type and major farming practices applied in the area. Statistical analysis of the data included descriptive statistics, analysis of variance and post-hoc tests, as well as regression analyses. This study succeeded in quantifying the extent and prevalence of contamination with medullated and coloured fibres in the South African wool clip. The overarching conclusions were: • Floating kemp is the most important contaminant of wool in South Africa, with the incidence of harsh kemp and coloured fibres being very low. • Generally, the most important areas that need attention in combatting contamination in the South African wool clip, are the Mixed Farming Summer Rainfall Region, the Semi-Arid Grassveld and the High Rainfall Grassland. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-04
A Combined Experimental and Computational Study of Hydridospirophosphorane Ligand Systems Featuring Halogenated Mandelic Acids
- Authors: Maritz, Marius Johann
- Date: 2023-12
- Subjects: Organic compounds -- Synthesis , Heterocyclic compounds , catalysis -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62096 , vital:71911
- Description: The search for new stereoselective catalysts remains important for the isolation of enantiomeric products from racemic mixtures. The need exists for these catalysts to be more efficient, to be more cost effective as well as be stable over time without undergoing changes in molecular structure and selectivity. The purpose of this research project was to experimentally synthesise and characterise asymmetric catalysts for the use in enantioselective synthesis. The catalysts consisted of the main group element phosphorous as central atom, with the phenyl rings of mandelic acid ligands monosubstituted with halogen atoms fluorine, chlorine and bromine in different configurations. Ligand binding resulted in the formation of hydridospirophosphorane structures, from which the molecular properties and binding geometry of these molecules could be explained by the theory of apicophilicity. Characterization was performed by NMR and IR spectroscopy as well as diffraction studies that provided the experimental crystal structures. The structural, energetic and spectroscopy results were compared to the theoretically obtained molecular properties using DFT analysis. Various interand intramolecular interactions that existed between molecules found in crystal packing environments were discussed. Additional properties that were investigated included modelling solvation effects, molecular orbital analysis, Hirshfeld surfaces, orbital and atomic energy and population analysis as well as ESP energy calculations with the optimized crystal structures as input. Molecular overlay comparisons were also performed between the experimental and optimized structures where the effectiveness of various DFT functionals and basis sets could be determined. The method with the best overall cost-to-accuracy ratio was found to be the triple-zeta def2-tzvp basis set with B3LYP functional theory and the addition of Grimme’s dispersion correction. Results indicated differences in crystal packing depending largely on the given halogen atoms present in the substituted phenyl rings, with differences observed in electronegativity and steric effects. One of the crystal systems showed additional interactions with solvent molecules, giving the impression that obtaining crystal void formation was possible. Alterations in the transition state activation energies between the isomers of each molecule were found to be present and supported the theory behind the mechanism of stereochemical induction. The studied compounds were therefore effective in isolating different enantiomeric ligands by means of energy differences between conformers and displayed unique catalytic properties resulting from the phosphorous main group element. The hydridospirophosphoranes conformers responsible for the lowest theoretically calculated activation energy induced crystallization as was seen by diffraction results for all compounds. Even as an intriguing observation, crystallization will largely depend on solubility rather than a specific conformer’s amount in solution. , Thesis (MSc) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Maritz, Marius Johann
- Date: 2023-12
- Subjects: Organic compounds -- Synthesis , Heterocyclic compounds , catalysis -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62096 , vital:71911
- Description: The search for new stereoselective catalysts remains important for the isolation of enantiomeric products from racemic mixtures. The need exists for these catalysts to be more efficient, to be more cost effective as well as be stable over time without undergoing changes in molecular structure and selectivity. The purpose of this research project was to experimentally synthesise and characterise asymmetric catalysts for the use in enantioselective synthesis. The catalysts consisted of the main group element phosphorous as central atom, with the phenyl rings of mandelic acid ligands monosubstituted with halogen atoms fluorine, chlorine and bromine in different configurations. Ligand binding resulted in the formation of hydridospirophosphorane structures, from which the molecular properties and binding geometry of these molecules could be explained by the theory of apicophilicity. Characterization was performed by NMR and IR spectroscopy as well as diffraction studies that provided the experimental crystal structures. The structural, energetic and spectroscopy results were compared to the theoretically obtained molecular properties using DFT analysis. Various interand intramolecular interactions that existed between molecules found in crystal packing environments were discussed. Additional properties that were investigated included modelling solvation effects, molecular orbital analysis, Hirshfeld surfaces, orbital and atomic energy and population analysis as well as ESP energy calculations with the optimized crystal structures as input. Molecular overlay comparisons were also performed between the experimental and optimized structures where the effectiveness of various DFT functionals and basis sets could be determined. The method with the best overall cost-to-accuracy ratio was found to be the triple-zeta def2-tzvp basis set with B3LYP functional theory and the addition of Grimme’s dispersion correction. Results indicated differences in crystal packing depending largely on the given halogen atoms present in the substituted phenyl rings, with differences observed in electronegativity and steric effects. One of the crystal systems showed additional interactions with solvent molecules, giving the impression that obtaining crystal void formation was possible. Alterations in the transition state activation energies between the isomers of each molecule were found to be present and supported the theory behind the mechanism of stereochemical induction. The studied compounds were therefore effective in isolating different enantiomeric ligands by means of energy differences between conformers and displayed unique catalytic properties resulting from the phosphorous main group element. The hydridospirophosphoranes conformers responsible for the lowest theoretically calculated activation energy induced crystallization as was seen by diffraction results for all compounds. Even as an intriguing observation, crystallization will largely depend on solubility rather than a specific conformer’s amount in solution. , Thesis (MSc) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2023
- Full Text:
- Date Issued: 2023-12
A critical exploration of the attitudes towards and knowledge of natural resource management amongst first-year Natural Resource Management students
- Authors: Jooste, Eileen
- Date: 2021-12
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's , text
- Identifier: http://hdl.handle.net/10948/53666 , vital:45688
- Description: Available literature suggests that there is a need to gain more understanding of what students’ environmental attitudes and knowledge are and how they are developed by education systems. Education, in general, plays an important role in students’ attitudes and their knowledge of the world around them. It can shape students’ awareness of their natural environment and contribute to their understanding of environmental issues. Education can also strengthen students’ critical thinking, build awareness, stimulate problem solving, and promote sustainable practices. It has the potential to empower students to address global challenges from their own diverse perspectives and prepare them to uphold the economy. Education can improve and maintain societal wellbeing and can help students to maintain the natural environment, along with achieving sustainable development. Environmental education, specifically, can play a big role in how students deal with the natural environment. The primary aim of this qualitative research study was to examine first-year students’ environmental attitudes and knowledge in the School of Natural Resource Management at the Nelson Mandela University George Campus, South Africa. First-year students’ environmental attitudes and knowledge were examined as they entered the university, and then again at the end of the first semester once they had completed a module in ecology. More specifically, at the outset of the research the objectives were (1) to establish an understanding of the baseline environmental attitudes and knowledge of first-year students who were undertaking three ecological modules being offered by the School of Natural Resource Management; (2) to assess the changes in the first-year students’ environmental attitudes and knowledge, using a post-intervention strategy; (3) to understand what type of teaching approaches were used by the lecturers teaching the ecological modules; and (4) to evaluate how the teaching approaches of the lecturers influenced the baseline environmental attitudes and knowledge of the student group. This research took place in the midst of the Corona Virus pandemic, which had significantly influenced the teaching and learning environment. Multiple education systems, including those of the Nelson Mandela University George Campus, had to rapidly transition to online teaching and learning. So, although unplanned for, this research could not ignore the rapid transition to online teaching and learning and the role it played in shaping the first-year School of Natural Resource Management students’ environmental attitudes and knowledge. It also impacted the teaching approaches of the environmental lecturers. An additional objective in response to the rapid transition to online teaching and learning was, therefore, added: (5) to understand the experiences of the first-year School of Natural Resource Management students and the three environmental lecturers who had to rapidly transition to online teaching and learning. Data was collected via questionnaires and semi-structured interviews with students and staff in the School of Natural Resource Management at Nelson Mandela University George Campus within three different natural resource management programs, namely Agriculture, Nature Conservation, and Forestry. Baseline questionnaires were conducted with 107 students for a baseline assessment as the students entered the university. An online post-intervention questionnaire was conducted with 33 of the initial group of students at the end of the semester for a post-intervention assessment. In-depth semi-structured interviews were conducted with three environmental lectures before they taught their three ecology modules in each of the programs. Additional online semi-structured interviews were also done with the same three environmental lectures after the rapid transition to online teaching and learning took place. The significant findings from this research were analyzed and discussed. This included the baseline environmental attitudes and knowledge of the student body upon arrival at the university and the changes in their environmental attitudes and knowledge after they were exposed to the ecology modules taught in each of the programs. The discussion also included the teaching approaches adopted by the environmental lecturers and the influence their teaching approaches had on the students’ environmental attitudes and knowledge. In addition, the results shed light on the experiences of students and lecturers during the rapid transition to online teaching and learning. The main conclusions reached were that the first-year School of Natural Resource Management students did not have a deep understanding of ecological concepts prior to arriving at university, but they did show a concern for the natural environment. Their lack of understanding was reduced as the students progressed with the ecology module. A greater understanding resulted in a change in students’ perspectives on the ecological module, their program, and the industry they were preparing to enter after being exposed to the ecology module. The environmental lecturers’ teaching approaches contributed to improving the students’ environmental attitudes and knowledge. When it came to the rapid transition to online teaching and learning, both the first-year School of Natural Resource Management students and environmental lecturers experienced benefits and challenges. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2021
- Full Text:
- Date Issued: 2021-12
- Authors: Jooste, Eileen
- Date: 2021-12
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's , text
- Identifier: http://hdl.handle.net/10948/53666 , vital:45688
- Description: Available literature suggests that there is a need to gain more understanding of what students’ environmental attitudes and knowledge are and how they are developed by education systems. Education, in general, plays an important role in students’ attitudes and their knowledge of the world around them. It can shape students’ awareness of their natural environment and contribute to their understanding of environmental issues. Education can also strengthen students’ critical thinking, build awareness, stimulate problem solving, and promote sustainable practices. It has the potential to empower students to address global challenges from their own diverse perspectives and prepare them to uphold the economy. Education can improve and maintain societal wellbeing and can help students to maintain the natural environment, along with achieving sustainable development. Environmental education, specifically, can play a big role in how students deal with the natural environment. The primary aim of this qualitative research study was to examine first-year students’ environmental attitudes and knowledge in the School of Natural Resource Management at the Nelson Mandela University George Campus, South Africa. First-year students’ environmental attitudes and knowledge were examined as they entered the university, and then again at the end of the first semester once they had completed a module in ecology. More specifically, at the outset of the research the objectives were (1) to establish an understanding of the baseline environmental attitudes and knowledge of first-year students who were undertaking three ecological modules being offered by the School of Natural Resource Management; (2) to assess the changes in the first-year students’ environmental attitudes and knowledge, using a post-intervention strategy; (3) to understand what type of teaching approaches were used by the lecturers teaching the ecological modules; and (4) to evaluate how the teaching approaches of the lecturers influenced the baseline environmental attitudes and knowledge of the student group. This research took place in the midst of the Corona Virus pandemic, which had significantly influenced the teaching and learning environment. Multiple education systems, including those of the Nelson Mandela University George Campus, had to rapidly transition to online teaching and learning. So, although unplanned for, this research could not ignore the rapid transition to online teaching and learning and the role it played in shaping the first-year School of Natural Resource Management students’ environmental attitudes and knowledge. It also impacted the teaching approaches of the environmental lecturers. An additional objective in response to the rapid transition to online teaching and learning was, therefore, added: (5) to understand the experiences of the first-year School of Natural Resource Management students and the three environmental lecturers who had to rapidly transition to online teaching and learning. Data was collected via questionnaires and semi-structured interviews with students and staff in the School of Natural Resource Management at Nelson Mandela University George Campus within three different natural resource management programs, namely Agriculture, Nature Conservation, and Forestry. Baseline questionnaires were conducted with 107 students for a baseline assessment as the students entered the university. An online post-intervention questionnaire was conducted with 33 of the initial group of students at the end of the semester for a post-intervention assessment. In-depth semi-structured interviews were conducted with three environmental lectures before they taught their three ecology modules in each of the programs. Additional online semi-structured interviews were also done with the same three environmental lectures after the rapid transition to online teaching and learning took place. The significant findings from this research were analyzed and discussed. This included the baseline environmental attitudes and knowledge of the student body upon arrival at the university and the changes in their environmental attitudes and knowledge after they were exposed to the ecology modules taught in each of the programs. The discussion also included the teaching approaches adopted by the environmental lecturers and the influence their teaching approaches had on the students’ environmental attitudes and knowledge. In addition, the results shed light on the experiences of students and lecturers during the rapid transition to online teaching and learning. The main conclusions reached were that the first-year School of Natural Resource Management students did not have a deep understanding of ecological concepts prior to arriving at university, but they did show a concern for the natural environment. Their lack of understanding was reduced as the students progressed with the ecology module. A greater understanding resulted in a change in students’ perspectives on the ecological module, their program, and the industry they were preparing to enter after being exposed to the ecology module. The environmental lecturers’ teaching approaches contributed to improving the students’ environmental attitudes and knowledge. When it came to the rapid transition to online teaching and learning, both the first-year School of Natural Resource Management students and environmental lecturers experienced benefits and challenges. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2021
- Full Text:
- Date Issued: 2021-12
A data-driven decision-making model for the third-party logistics industry in Africa
- Authors: Moyo, Faith
- Date: 2021-12
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/53875 , vital:46022
- Description: Third-party logistics (3PL) providers have continued to be key players in the supply chain network and have witnessed a growth in the usage of information technology. This growth has enhanced the volume of structured and unstructured data that is collected at a high velocity, and is of rich variety, sometimes described as “Big Data”. Leaders in the 3PL industry are constantly seeking to effectively and efficiently mature their abilities to exploit this data to gain business value through data-driven decision-making (DDDM). DDDM helps the leaders to reduce the reliance they place on observations and intuition to make crucial business decisions in a volatile business environment. The aim of this research was to develop a prescriptive model for DDDM in 3PLs. The model consists of iterative elements that prescribe guidelines to decision-makers in the 3PL industry on how to adopt DDDM. A literature review of existing theoretical frameworks and models for DDDM was conducted to determine the extent to which they contribute towards DDDM for 3PLs. The Design-Science Research Methodology (DSRM) was followed to address the aim of the research and applied to pragmatically and iteratively develop and evaluate the artefact (the model for DDDM) in the real-world context of a 3PL. The literature findings revealed that the challenges with DDDM in organisations include three main categories of challenges related to data quality, data management, vision and capabilities. Once the challenges with DDDM were established, a prescriptive model was designed and developed for DDDM in 3PLs. Qualitative data was collected from semi-structured interviews to gain an understanding of the problems and possible solutions in the real-world context of 3PLs. An As-Is Analysis in the real-world case 3PL company confirmed the challenges identified in literature, and that data is still used in the 3PL company for descriptive and diagnostic analytics to aid with the decision-making processes. This highlights that there is still room for maturity into using data for predictive and prescriptive analytics that will, in turn, improve the decision-making process. An improved second version of the model was demonstrated to the participants (the targeted users), who had the opportunity to evaluate the model. The findings revealed that the model provided clear guidelines on how to make data-driven decisions and that the feedback loop and the data culture aspects highlighted in the design were some of the important features of the model. Some improvements were suggested by participants. A field study of three data analytics tools was conducted to identify the advantages and disadvantages of each as well as to highlight the status of DDDM at the real-world case 3PL. The limitations of the second version of the model, together with the recommendations from the participants were used to inform the improved and revised third version of the model. , Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2021
- Full Text:
- Date Issued: 2021-12
- Authors: Moyo, Faith
- Date: 2021-12
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/53875 , vital:46022
- Description: Third-party logistics (3PL) providers have continued to be key players in the supply chain network and have witnessed a growth in the usage of information technology. This growth has enhanced the volume of structured and unstructured data that is collected at a high velocity, and is of rich variety, sometimes described as “Big Data”. Leaders in the 3PL industry are constantly seeking to effectively and efficiently mature their abilities to exploit this data to gain business value through data-driven decision-making (DDDM). DDDM helps the leaders to reduce the reliance they place on observations and intuition to make crucial business decisions in a volatile business environment. The aim of this research was to develop a prescriptive model for DDDM in 3PLs. The model consists of iterative elements that prescribe guidelines to decision-makers in the 3PL industry on how to adopt DDDM. A literature review of existing theoretical frameworks and models for DDDM was conducted to determine the extent to which they contribute towards DDDM for 3PLs. The Design-Science Research Methodology (DSRM) was followed to address the aim of the research and applied to pragmatically and iteratively develop and evaluate the artefact (the model for DDDM) in the real-world context of a 3PL. The literature findings revealed that the challenges with DDDM in organisations include three main categories of challenges related to data quality, data management, vision and capabilities. Once the challenges with DDDM were established, a prescriptive model was designed and developed for DDDM in 3PLs. Qualitative data was collected from semi-structured interviews to gain an understanding of the problems and possible solutions in the real-world context of 3PLs. An As-Is Analysis in the real-world case 3PL company confirmed the challenges identified in literature, and that data is still used in the 3PL company for descriptive and diagnostic analytics to aid with the decision-making processes. This highlights that there is still room for maturity into using data for predictive and prescriptive analytics that will, in turn, improve the decision-making process. An improved second version of the model was demonstrated to the participants (the targeted users), who had the opportunity to evaluate the model. The findings revealed that the model provided clear guidelines on how to make data-driven decisions and that the feedback loop and the data culture aspects highlighted in the design were some of the important features of the model. Some improvements were suggested by participants. A field study of three data analytics tools was conducted to identify the advantages and disadvantages of each as well as to highlight the status of DDDM at the real-world case 3PL. The limitations of the second version of the model, together with the recommendations from the participants were used to inform the improved and revised third version of the model. , Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2021
- Full Text:
- Date Issued: 2021-12
A Functional Data Analysis approach to understand patterns imbedded within various data types
- Authors: Mangisa, Siphumlile
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Data mining
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/52091 , vital:43426
- Description: The thesis investigates the use of the novel Functional Data Analysis (FDA) methods in tackling various data types. Strong motivation is provided for the use of interesting opportunities offered by FDA to analyse not only economic data, but generally, data from any domain. The use of these methods is illustrated using three unique self-contained case-studies from econometrics. , Thesis (PhD) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2021
- Full Text: false
- Date Issued: 2021-04
- Authors: Mangisa, Siphumlile
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Data mining
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/52091 , vital:43426
- Description: The thesis investigates the use of the novel Functional Data Analysis (FDA) methods in tackling various data types. Strong motivation is provided for the use of interesting opportunities offered by FDA to analyse not only economic data, but generally, data from any domain. The use of these methods is illustrated using three unique self-contained case-studies from econometrics. , Thesis (PhD) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2021
- Full Text: false
- Date Issued: 2021-04
A model to predict the development of preeclampsia in South African women
- Authors: Smith, Nathan
- Date: 2022-12
- Subjects: Medical instruments and apparatus -- Design and construction , Hypertension in pregnancy -- measurements-- South Africa , Fetus -- Physiology
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/59980 , vital:62724
- Description: Preeclampsia is the new onset of hypertension and is one of the leading causes of maternal mortality in South Africa and the world. Preeclampsia is usually diagnosed after 20 weeks’ gestation. Due to South Africa’s poor level of antenatal care, the prediction of pregnant women at risk of developing preeclampsia can be an essential component of improving the level of antenatal. This study used an antenatal care dataset from a South African obstetrician. A review of the literature and existing systems was conducted to identify the eight risk factors. These risk factors are systolic blood pressure, diastolic blood pressure, maternal age, body mass index, diabetes status, hypertension history, nulliparity, and maternal disease. This study used antenatal care datasets from a South African obstetrician. Two models were developed that could accurately predict the development of preeclampsia, one before 16 weeks’ gestation and the other within three check-ups. The model was evaluated using five evaluation metrics: classification accuracy, area under the curve, precision, recall and F-Score. The results of this study show a promising future for the use of machine learning models in health care. To the researcher’s knowledge, this model is the first machine learning model for predicting preeclampsia using a South African dataset. Future work will revolve around validating the model on data collected from field studies in hospitals and clinics around South Africa , Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2022
- Full Text:
- Date Issued: 2022-12
- Authors: Smith, Nathan
- Date: 2022-12
- Subjects: Medical instruments and apparatus -- Design and construction , Hypertension in pregnancy -- measurements-- South Africa , Fetus -- Physiology
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/59980 , vital:62724
- Description: Preeclampsia is the new onset of hypertension and is one of the leading causes of maternal mortality in South Africa and the world. Preeclampsia is usually diagnosed after 20 weeks’ gestation. Due to South Africa’s poor level of antenatal care, the prediction of pregnant women at risk of developing preeclampsia can be an essential component of improving the level of antenatal. This study used an antenatal care dataset from a South African obstetrician. A review of the literature and existing systems was conducted to identify the eight risk factors. These risk factors are systolic blood pressure, diastolic blood pressure, maternal age, body mass index, diabetes status, hypertension history, nulliparity, and maternal disease. This study used antenatal care datasets from a South African obstetrician. Two models were developed that could accurately predict the development of preeclampsia, one before 16 weeks’ gestation and the other within three check-ups. The model was evaluated using five evaluation metrics: classification accuracy, area under the curve, precision, recall and F-Score. The results of this study show a promising future for the use of machine learning models in health care. To the researcher’s knowledge, this model is the first machine learning model for predicting preeclampsia using a South African dataset. Future work will revolve around validating the model on data collected from field studies in hospitals and clinics around South Africa , Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2022
- Full Text:
- Date Issued: 2022-12
A social media analytics framework for decision-making in citizen relationship management
- Authors: Yakobi, Khulekani
- Date: 2022-12
- Subjects: Social Media Analytics -- South Africa , Decision making --Mathematical models , Service delivery
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/60048 , vital:62815
- Description: Globally social media has shown unprecedented levels of adoption and Social Media Analytics (SMA) is a rapidly growing topic. For governments, SMA holds the promise of providing tools and frameworks to collect, monitor, analyse and visualise social media data, usually driven by specific requirements from a target application. However, social media data is noisy and unstructured, and organisations struggle to extract knowledge from this data, and convert it into actual intelligence. This study argues that SMA can support intelligent decision-making for Citizen Relationship Management (CzRM). CzRM is a growing effort of governments around the world to strive to respond rapidly to their citizens by fostering a closer relationship thereby creating more effective and efficient service delivery. However, there is a little evidence in literature on empirical studies of any existing decision-making framework for CzRM and SMA adoption. In particular, there is a gap with regards incorporating SMA into decision-making for CzRM of governments, particularly in developing countries like South Africa. The aim of this study was to develop a framework that provides guidelines, including methods and tools, incorporating SMA into decision-making for CzRM in the Gauteng Provincial Government (GPG) and the Free State Provincial Government (FSPG) of South Africa. A Systematic Literature Review (SLR) and conceptual analysis method was conducted to design the Social Media Analytics Framework for Decision-making in the context of CzRM (the SMAF). The findings from the literature review revealed several benefits and challenges with SMA, in particular the shortage of skills, guidelines, methods and tools for SMA. These challenges were used to draft guidelines that were included in the framework, which consists of five components that can be used to derive intelligent information from SMA. The pragmatic philosophy and a case study design was used to generate an in-depth, multifaceted understanding of the underlying problems in the case of the GPG and the FSPG. The German North-West Metropolitan region was used as a third case study to provide a more global perspective and a case of a developed country in terms of Gross Domestic Product. The scope of the study was limited to social media posts by provincial citizens related to CzRM and service delivery. Both formative and summative evaluations of the proposed theoretical framework were conducted. The formative evaluation was conducted v | Page as an Expert Review to receive feedback of the framework from the experts in the field of Computer Science and Information Systems. The findings validated the framework and some minor improvements were made based on the experts’ recommendations. Focus Group Discussions (FGDs) with participants from government managers and decision makers in the three cases were conducted. Case documents for the three cases were collected and reviewed. All collected data was analysed using the Qualitative Content Analysis (QCA) method and common categories and themes were identified. Summative evaluations were conducted in the form of a Field Study, which consisted of an analysis of Twitter data from the three cases, and a closing FGD with Business Intelligence (BI) experts at the primary case of the e-Government department of the GPG. The findings revealed that SMA has been adopted in all three cases; however, while their strategies are comprehensive their implementations are very much in their early stages. The findings also highlighted the status of SMA in government and some potential gaps and areas for implementing the framework. , Thesis (PhD) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2022
- Full Text:
- Date Issued: 2022-12
- Authors: Yakobi, Khulekani
- Date: 2022-12
- Subjects: Social Media Analytics -- South Africa , Decision making --Mathematical models , Service delivery
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/60048 , vital:62815
- Description: Globally social media has shown unprecedented levels of adoption and Social Media Analytics (SMA) is a rapidly growing topic. For governments, SMA holds the promise of providing tools and frameworks to collect, monitor, analyse and visualise social media data, usually driven by specific requirements from a target application. However, social media data is noisy and unstructured, and organisations struggle to extract knowledge from this data, and convert it into actual intelligence. This study argues that SMA can support intelligent decision-making for Citizen Relationship Management (CzRM). CzRM is a growing effort of governments around the world to strive to respond rapidly to their citizens by fostering a closer relationship thereby creating more effective and efficient service delivery. However, there is a little evidence in literature on empirical studies of any existing decision-making framework for CzRM and SMA adoption. In particular, there is a gap with regards incorporating SMA into decision-making for CzRM of governments, particularly in developing countries like South Africa. The aim of this study was to develop a framework that provides guidelines, including methods and tools, incorporating SMA into decision-making for CzRM in the Gauteng Provincial Government (GPG) and the Free State Provincial Government (FSPG) of South Africa. A Systematic Literature Review (SLR) and conceptual analysis method was conducted to design the Social Media Analytics Framework for Decision-making in the context of CzRM (the SMAF). The findings from the literature review revealed several benefits and challenges with SMA, in particular the shortage of skills, guidelines, methods and tools for SMA. These challenges were used to draft guidelines that were included in the framework, which consists of five components that can be used to derive intelligent information from SMA. The pragmatic philosophy and a case study design was used to generate an in-depth, multifaceted understanding of the underlying problems in the case of the GPG and the FSPG. The German North-West Metropolitan region was used as a third case study to provide a more global perspective and a case of a developed country in terms of Gross Domestic Product. The scope of the study was limited to social media posts by provincial citizens related to CzRM and service delivery. Both formative and summative evaluations of the proposed theoretical framework were conducted. The formative evaluation was conducted v | Page as an Expert Review to receive feedback of the framework from the experts in the field of Computer Science and Information Systems. The findings validated the framework and some minor improvements were made based on the experts’ recommendations. Focus Group Discussions (FGDs) with participants from government managers and decision makers in the three cases were conducted. Case documents for the three cases were collected and reviewed. All collected data was analysed using the Qualitative Content Analysis (QCA) method and common categories and themes were identified. Summative evaluations were conducted in the form of a Field Study, which consisted of an analysis of Twitter data from the three cases, and a closing FGD with Business Intelligence (BI) experts at the primary case of the e-Government department of the GPG. The findings revealed that SMA has been adopted in all three cases; however, while their strategies are comprehensive their implementations are very much in their early stages. The findings also highlighted the status of SMA in government and some potential gaps and areas for implementing the framework. , Thesis (PhD) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2022
- Full Text:
- Date Issued: 2022-12
A spatial assessment of riparian vegetation density and implications for streambank erosion in relation to land tenure in the Mgwalana Catchment, Eastern Cape Province, South Africa
- Authors: Maxama, Asakhile
- Date: 2021-12
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/53864 , vital:46026
- Description: Riparian vegetation provides an array of various ecosystem functions and has significantly shaped the conditions of catchments. It has strong controls on fluvial geomorphology and erosion processes. The Mgwalana catchment has been intensively studied over the years and the current environmental condition of the study has been linked to land use history. The catchment has been subjected to land use/cover changes (LUCC) over the years. However, spatial variations in riparian vegetation, their implications for stream bank stability and the contribution of land tenure systems to stream channel degradation are poorly understood. The study sought to assess the implications of the spatial variations in riparian vegetation density for stream bank erosion in relation to land tenure on a catchment scale. Land tenure units comprising the catchment of study are traditional and betterment villages (communal lands), and former white commercial farms. A three-pronged approach using GIS and remote sensing, field investigations and laboratory procedures for soil analysis was employed in this study. Variations of riparian vegetation density in the catchment were mapped using ArcGIS for the two land tenure units to assess the spatial variations of riparian density along stream reaches and to determine the spatial relationship between land tenure units and riparian vegetation diminution. Other mapped shape files include sediment accumulation zones to analyse the spatial relationship between riparian vegetation density and sediment sinks. LUCC classification and analysis of the Normalized Difference Vegetation Index (NDVI) were carried out in IDRISI Selva, using Landsat 8 TM imagery of 2018 to represent the current spatial riparian vegetation variations in the catchment. Field investigations were conducted to determine the coupling among hillslope gully erosion, riparian vegetation density and sink areas; and to assess physical characteristics of soil. This would permit an assessment of the implications of riparian vegetation for stream bank erosion and sediment accumulation within the tenure units. Soil samples were taken from scantily and densely vegetated stream reaches, as well as measurements of channel widths and depths. Analyses of soil physical properties viz; grain size distribution, bulk density, soil texture and aggregate stability were done. Results demonstrated that a sparse riparian vegetation distribution was consistent with the communal villages, confined to the upper catchment area. Dense riparian vegetation distribution was consistent with former commercial farms in the lower catchment area. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2021
- Full Text:
- Date Issued: 2021-12
- Authors: Maxama, Asakhile
- Date: 2021-12
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/53864 , vital:46026
- Description: Riparian vegetation provides an array of various ecosystem functions and has significantly shaped the conditions of catchments. It has strong controls on fluvial geomorphology and erosion processes. The Mgwalana catchment has been intensively studied over the years and the current environmental condition of the study has been linked to land use history. The catchment has been subjected to land use/cover changes (LUCC) over the years. However, spatial variations in riparian vegetation, their implications for stream bank stability and the contribution of land tenure systems to stream channel degradation are poorly understood. The study sought to assess the implications of the spatial variations in riparian vegetation density for stream bank erosion in relation to land tenure on a catchment scale. Land tenure units comprising the catchment of study are traditional and betterment villages (communal lands), and former white commercial farms. A three-pronged approach using GIS and remote sensing, field investigations and laboratory procedures for soil analysis was employed in this study. Variations of riparian vegetation density in the catchment were mapped using ArcGIS for the two land tenure units to assess the spatial variations of riparian density along stream reaches and to determine the spatial relationship between land tenure units and riparian vegetation diminution. Other mapped shape files include sediment accumulation zones to analyse the spatial relationship between riparian vegetation density and sediment sinks. LUCC classification and analysis of the Normalized Difference Vegetation Index (NDVI) were carried out in IDRISI Selva, using Landsat 8 TM imagery of 2018 to represent the current spatial riparian vegetation variations in the catchment. Field investigations were conducted to determine the coupling among hillslope gully erosion, riparian vegetation density and sink areas; and to assess physical characteristics of soil. This would permit an assessment of the implications of riparian vegetation for stream bank erosion and sediment accumulation within the tenure units. Soil samples were taken from scantily and densely vegetated stream reaches, as well as measurements of channel widths and depths. Analyses of soil physical properties viz; grain size distribution, bulk density, soil texture and aggregate stability were done. Results demonstrated that a sparse riparian vegetation distribution was consistent with the communal villages, confined to the upper catchment area. Dense riparian vegetation distribution was consistent with former commercial farms in the lower catchment area. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2021
- Full Text:
- Date Issued: 2021-12
A study of the airflow on the windward slope of a transverse dune in the Alexandria coastal dunefield
- Authors: Burkinshaw, Jennifer Ruth
- Date: 2021-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52734 , vital:43883
- Description: Our understanding of the evolution of dune morphology has been hampered by a lack of empirical observations of airflow behaviour over dune forms. Sand dunes intrude into the atmospheric boundary layer and convergence of streamlines results in an acceleration of airflow up the windward slopes of dunes. This study examines the airflow structure and corresponding bedform development on the windward slope of a 7 m high transverse dune on the edge of the Alexandria coastal dunefield, Algoa Bay, South Africa. The Alexandria dunefield is subjected to a trimodal wind regime, consisting of the dominant south-westerly which blows all year round, summer easterlies and winter northwesterlies. The morphology of the study dune, Dune13, is controlled by the easterlies and north-westerlies, and reverses seasonally with respect to these two winds. Seven section lines 30 m apart and normal to the dune crest were surveyed regularly over the period of a year to monitor the reversal process. Three detailed topographic surveys were also done during this period. Airflow behaviour was monitored during the year. Wind speed profiles on the windward slope of the dune were measured using 4 to 5 vertical arrays of anemometers positioned from the base of the dune to the crest on a 1 selected section line. Usually 4 to 5 anemometers were deployed in each vertical array, from a height of 6 to 10 cm above the surface, up to a height of 150 cm above the surface. Initially 8 microanemometers were available; ultimately 28 anemometers were run simultaneously. An independent weather station at an elevation of 6 m recorded the unaccelerated flow. Local gradient measurements and erosion and deposition rates were recorded along selected section lines. Strong summer easterly winds (14 m/sec at 1.4 m above the dune crest) were measured on a dune slope in the process of being transformed from a slipface to a stoss slope. The following winter, light north-westerly winds (typically B m/sec at 1.6 m above the dune crest) were measured on the new windward slope already reversed by the prevailing winter wind. Airflow data confirm the compression of airflow against the windward slope resulting in a non-logarithmic wind speed profile. Compression results in an increased shear velocity within 30 cm of the dune surface, and the dune slope is eroded. Higher up in the wind speed profile, shear velocity decreases to 0.1 m/sec. It is not known at what height the wind speed profile recovers from the intrusion of the dune into the boundary layer. High values of shear velocity (1.6 m/sec) above the rounded crestal area of the dune record the recovery of the wind speed profile from flow divergence, which is a response to the rapid reduction of dune gradient and is accompanied by deposition of sand in this region. 2 The erosion pin data act as a simple and sensitive test for changes in gradient, reflecting the dune's response to changes in the airflow regime. The shape of the dune plays a major role in determining the extent of the compression and the distribution of shear velocity up the slope. Increased shear velocity is experienced on that part of the slope which is nonaerodynamic with respect to the prevailing wind. Under unidirectional conditions, feedback between flow and form results ultimately in a slope with a curvature such that shear velocity increases systematically upslope. The survey data and erosion pin data record the reversal process as the dune achieves a new steady state during each wind season. The existence of a non-logarithmic wind speed profile makes it difficult to know what relevant measure of shear velocity is to be used in sand transport equations. Future work should include wind speed measurements within 10 cm of the surface. An ideal study modelling aeolian bedform development would utilise wind tunnel measurements, combined with field measurements such as obtained in this study, for comparison with numerical modelling. The study needs to be extended to 3-dimensional airflow measurements. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Burkinshaw, Jennifer Ruth
- Date: 2021-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52734 , vital:43883
- Description: Our understanding of the evolution of dune morphology has been hampered by a lack of empirical observations of airflow behaviour over dune forms. Sand dunes intrude into the atmospheric boundary layer and convergence of streamlines results in an acceleration of airflow up the windward slopes of dunes. This study examines the airflow structure and corresponding bedform development on the windward slope of a 7 m high transverse dune on the edge of the Alexandria coastal dunefield, Algoa Bay, South Africa. The Alexandria dunefield is subjected to a trimodal wind regime, consisting of the dominant south-westerly which blows all year round, summer easterlies and winter northwesterlies. The morphology of the study dune, Dune13, is controlled by the easterlies and north-westerlies, and reverses seasonally with respect to these two winds. Seven section lines 30 m apart and normal to the dune crest were surveyed regularly over the period of a year to monitor the reversal process. Three detailed topographic surveys were also done during this period. Airflow behaviour was monitored during the year. Wind speed profiles on the windward slope of the dune were measured using 4 to 5 vertical arrays of anemometers positioned from the base of the dune to the crest on a 1 selected section line. Usually 4 to 5 anemometers were deployed in each vertical array, from a height of 6 to 10 cm above the surface, up to a height of 150 cm above the surface. Initially 8 microanemometers were available; ultimately 28 anemometers were run simultaneously. An independent weather station at an elevation of 6 m recorded the unaccelerated flow. Local gradient measurements and erosion and deposition rates were recorded along selected section lines. Strong summer easterly winds (14 m/sec at 1.4 m above the dune crest) were measured on a dune slope in the process of being transformed from a slipface to a stoss slope. The following winter, light north-westerly winds (typically B m/sec at 1.6 m above the dune crest) were measured on the new windward slope already reversed by the prevailing winter wind. Airflow data confirm the compression of airflow against the windward slope resulting in a non-logarithmic wind speed profile. Compression results in an increased shear velocity within 30 cm of the dune surface, and the dune slope is eroded. Higher up in the wind speed profile, shear velocity decreases to 0.1 m/sec. It is not known at what height the wind speed profile recovers from the intrusion of the dune into the boundary layer. High values of shear velocity (1.6 m/sec) above the rounded crestal area of the dune record the recovery of the wind speed profile from flow divergence, which is a response to the rapid reduction of dune gradient and is accompanied by deposition of sand in this region. 2 The erosion pin data act as a simple and sensitive test for changes in gradient, reflecting the dune's response to changes in the airflow regime. The shape of the dune plays a major role in determining the extent of the compression and the distribution of shear velocity up the slope. Increased shear velocity is experienced on that part of the slope which is nonaerodynamic with respect to the prevailing wind. Under unidirectional conditions, feedback between flow and form results ultimately in a slope with a curvature such that shear velocity increases systematically upslope. The survey data and erosion pin data record the reversal process as the dune achieves a new steady state during each wind season. The existence of a non-logarithmic wind speed profile makes it difficult to know what relevant measure of shear velocity is to be used in sand transport equations. Future work should include wind speed measurements within 10 cm of the surface. An ideal study modelling aeolian bedform development would utilise wind tunnel measurements, combined with field measurements such as obtained in this study, for comparison with numerical modelling. The study needs to be extended to 3-dimensional airflow measurements. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2021
- Full Text:
- Date Issued: 2021-04
A theoretical study of alkoxyl radical and radical cation mediated cyclisation reactions in unsaturated alkanols
- Authors: Lee, Peter Mattison Clarke
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Density functionals
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/52130 , vital:43430
- Description: A large part of this computational study focussed on selectivity patterns for 4-penten- 1-oxyl radical 1,5- and 1,6-cyclisations and for those of analogous 5-hexenyl, 4- penten-1-aminyl, 4-penten-1-iminyl and 3-phenylpropan-1-oxyl radicals. The study furthermore included cyclisation reactions of the radical cations of 4-penten-1-ol and 3-phenylpropan-1-ol. Calculations were performed for all applicable species involved in the two cyclisation modes studied, i.e. 1,5- and 1,6-cyclisation. These species included radical and radical cation precursors, as well as relevant radical transition state structures and radical adducts. All cyclisation systems investigated used the Density Functional Theory (DFT) functional B3LYP with a combination of eight basis sets. Each basis set used was a progressively higher level of theory than B3LYP/6-31G* which was used as a starting point. Cyclisations for unsubstituted species, e.g. the 4-penten-1-oxyl radical 1,5- and 1,6-cyclisations, were also simulated using the ωB97X-D and ωB97X-V functionals which account for dispersive effects. The same set of eight basis sets were used with these two functionals. , Thesis (PhD) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2021
- Full Text: false
- Date Issued: 2021-04
- Authors: Lee, Peter Mattison Clarke
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Density functionals
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/52130 , vital:43430
- Description: A large part of this computational study focussed on selectivity patterns for 4-penten- 1-oxyl radical 1,5- and 1,6-cyclisations and for those of analogous 5-hexenyl, 4- penten-1-aminyl, 4-penten-1-iminyl and 3-phenylpropan-1-oxyl radicals. The study furthermore included cyclisation reactions of the radical cations of 4-penten-1-ol and 3-phenylpropan-1-ol. Calculations were performed for all applicable species involved in the two cyclisation modes studied, i.e. 1,5- and 1,6-cyclisation. These species included radical and radical cation precursors, as well as relevant radical transition state structures and radical adducts. All cyclisation systems investigated used the Density Functional Theory (DFT) functional B3LYP with a combination of eight basis sets. Each basis set used was a progressively higher level of theory than B3LYP/6-31G* which was used as a starting point. Cyclisations for unsubstituted species, e.g. the 4-penten-1-oxyl radical 1,5- and 1,6-cyclisations, were also simulated using the ωB97X-D and ωB97X-V functionals which account for dispersive effects. The same set of eight basis sets were used with these two functionals. , Thesis (PhD) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2021
- Full Text: false
- Date Issued: 2021-04
A value alignment smart city stakeholder model
- Van der Hoogen, Anthea Vivian
- Authors: Van der Hoogen, Anthea Vivian
- Date: 2021-12
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/54129 , vital:46309
- Description: The concept of a Smart City has evolved over the last three decades and has attracted the increasing interest of the scientific research community. Unfortunately, many Smart City projects and initiatives do not provide the value expected by all the stakeholders. Many of the reasons for this relate to a lack of data management, data integration, data access and stakeholder participation. People are an integral part of any city’s ecosystem, and the Smart City concept was introduced to address the challenges of an ever-growing global population leading to the risk of depletion of economic, environmental and social resources. The problem addressed in this study is based on the challenges preventing the creation of the value of smart cities or stakeholders. Limited research has been published on the status of Smart City initiatives or on the impact of various success factors on the potential value creation for stakeholders including citizens. Studies on initiatives in developing countries, such as South Africa are even less. Whilst some challenges and constraints related to smart cities in Africa have been reported, there are no studies reporting on initiatives across the data value chain that consider all types of stakeholders, nor the impact of these initiatives. This study addressed this gap in research and designed a theoretical Value Alignment Smart City Stakeholder (VASCS) Model based on a Systematic Literature Review and a review of related theories. The model has important components that should form part of any Smart City project or Smart City initiative. These five main components are: 1) nine Smart City dimensions with related success factors; 2) four stakeholder roles (enablers, providers, utilisers and users); 3) the data value chain; and 4) the five phases of stakeholder benefits/value realisation that can be linked to; 5) stakeholder value alignment. This study applied the VASCS Model to Smart City initiatives in two case studies in the Eastern Cape Province of South Africa, which were the Nelson Mandela Bay and Buffalo City to investigate and understand the status of such initiatives and the alignment of value thereof. The stakeholder interviews were conducted in two rounds with various stakeholders of Smart City initiatives, referred to as cases in the two case studies. An expert review of the VASCS Model was conducted with eight experts in the field of Information Systems and Smart Cities. The findings of this review served to confirm the components of the model, with only minor improvements recommended. It was confirmed that all of the components need to be considered in planning Smart City projects. The first round consisted of six interviews with enablers and providers and the second round consisted of 22 interviews with users, utilisers and citizens. The interviews investigated the value and impact experienced by stakeholders of these initiatives, with a particular focus on the users, utilisers and citizens of the cases. The interview data was transcribed and qualitatively analysed by using Atlas.tiand Excel. The data was analysed according to the Technological, Organisational and Environmental theory constructs and other identified themes. The interview analysis findings revealed several drivers for these initiatives, which were primarily cost reduction, integration and quality assurance. The results also highlighted access to resources, such as technical skills as a challenge. Another challenge identified was connectivity related to access to data and the digital and physical divide that can impact decision making. The main benefits of Smart City initiatives highlighted were the provision of infrastructure, education and training and digitalisation. The theoretical contribution of this study is the VASCS Model, which can assist other researchers and practitioners with knowledge of the factors, drivers, challenges and value obtained in Smart City initiatives. The model has two supplementary components: A Stakeholder Classification Model and a Smart City Success Factor Evaluation Template. The practical contribution of this study is the potential use of the VASCS Model by practitioners, city management, researchers and other stakeholders, who can use the model, with the related model and template for planning and evaluating Smart City initiatives. The model can be used to classify the digital activities according to a Smart City’s success factors while evaluating the value created by these activities. The impact of these initiatives can then be assessed through value realisation and alignment for stakeholders. The scientific contribution is the adoption of the model to the cases in the Eastern Cape. To reveal in depth, rich, interview findings that provide important lessons learnt relating to the value created for the stakeholders and the addition of these findings to the body of knowledge. , Thesis (PhD) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2021
- Full Text:
- Date Issued: 2021-12
- Authors: Van der Hoogen, Anthea Vivian
- Date: 2021-12
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/54129 , vital:46309
- Description: The concept of a Smart City has evolved over the last three decades and has attracted the increasing interest of the scientific research community. Unfortunately, many Smart City projects and initiatives do not provide the value expected by all the stakeholders. Many of the reasons for this relate to a lack of data management, data integration, data access and stakeholder participation. People are an integral part of any city’s ecosystem, and the Smart City concept was introduced to address the challenges of an ever-growing global population leading to the risk of depletion of economic, environmental and social resources. The problem addressed in this study is based on the challenges preventing the creation of the value of smart cities or stakeholders. Limited research has been published on the status of Smart City initiatives or on the impact of various success factors on the potential value creation for stakeholders including citizens. Studies on initiatives in developing countries, such as South Africa are even less. Whilst some challenges and constraints related to smart cities in Africa have been reported, there are no studies reporting on initiatives across the data value chain that consider all types of stakeholders, nor the impact of these initiatives. This study addressed this gap in research and designed a theoretical Value Alignment Smart City Stakeholder (VASCS) Model based on a Systematic Literature Review and a review of related theories. The model has important components that should form part of any Smart City project or Smart City initiative. These five main components are: 1) nine Smart City dimensions with related success factors; 2) four stakeholder roles (enablers, providers, utilisers and users); 3) the data value chain; and 4) the five phases of stakeholder benefits/value realisation that can be linked to; 5) stakeholder value alignment. This study applied the VASCS Model to Smart City initiatives in two case studies in the Eastern Cape Province of South Africa, which were the Nelson Mandela Bay and Buffalo City to investigate and understand the status of such initiatives and the alignment of value thereof. The stakeholder interviews were conducted in two rounds with various stakeholders of Smart City initiatives, referred to as cases in the two case studies. An expert review of the VASCS Model was conducted with eight experts in the field of Information Systems and Smart Cities. The findings of this review served to confirm the components of the model, with only minor improvements recommended. It was confirmed that all of the components need to be considered in planning Smart City projects. The first round consisted of six interviews with enablers and providers and the second round consisted of 22 interviews with users, utilisers and citizens. The interviews investigated the value and impact experienced by stakeholders of these initiatives, with a particular focus on the users, utilisers and citizens of the cases. The interview data was transcribed and qualitatively analysed by using Atlas.tiand Excel. The data was analysed according to the Technological, Organisational and Environmental theory constructs and other identified themes. The interview analysis findings revealed several drivers for these initiatives, which were primarily cost reduction, integration and quality assurance. The results also highlighted access to resources, such as technical skills as a challenge. Another challenge identified was connectivity related to access to data and the digital and physical divide that can impact decision making. The main benefits of Smart City initiatives highlighted were the provision of infrastructure, education and training and digitalisation. The theoretical contribution of this study is the VASCS Model, which can assist other researchers and practitioners with knowledge of the factors, drivers, challenges and value obtained in Smart City initiatives. The model has two supplementary components: A Stakeholder Classification Model and a Smart City Success Factor Evaluation Template. The practical contribution of this study is the potential use of the VASCS Model by practitioners, city management, researchers and other stakeholders, who can use the model, with the related model and template for planning and evaluating Smart City initiatives. The model can be used to classify the digital activities according to a Smart City’s success factors while evaluating the value created by these activities. The impact of these initiatives can then be assessed through value realisation and alignment for stakeholders. The scientific contribution is the adoption of the model to the cases in the Eastern Cape. To reveal in depth, rich, interview findings that provide important lessons learnt relating to the value created for the stakeholders and the addition of these findings to the body of knowledge. , Thesis (PhD) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2021
- Full Text:
- Date Issued: 2021-12
An assessment of different methods for measuring mammal diversity in two Southern African arid ecosystems.
- Authors: Burt, Chloe
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Biodiversity -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52338 , vital:43591
- Description: A current critical environmental problem is the loss of biodiversity. To allow for adaptive management and effective conservation interventions, reliable data needs to be readily available and effectively collected. To gather reliable data, the most appropriate method must be used. The aim of this thesis was to compare the effectiveness and efficiency of different mammal diversity sampling techniques, including discussing specificities and complementarity of each. I also assessed the limitation of methods in terms of the influence of species traits on detectability. I used standard mammal field methods such as block transects, camera traps, track plates, spotlight surveys, mist nets, acoustic surveys, and live traps for a wide range of mammal taxa, and also included the use of local knowledge in the comparison. I assessed the cost-efficiency of each method by determining the cost per species. The efficiency of each method was assessed by observing when the species accumulation curve reached an asymptote. The effectiveness was determined by the species richness and the taxonomic groups the method detected. My results indicated that block transects were the most efficient and effective method to assess species richness. However, a combination of methods allowed for a more comprehensive survey and my results indicate that block transects and live traps were the best combination. It is important to note, not only the effectiveness and efficiency of methods be assessed, but also their limitations. I therefore also assessed the influence of species traits on the detectability of five methods. The species traits that I tested were body size, diet, activity, and if they lived in groups. On both study areas, body size was the main trait that influenced detectability with most field methods. Diet and activity had varying influence on detectability depending on the method. Group living did not significantly influence detectability. Based on my results, I provide guidelines for choosing the most appropriate survey method for targeted studies on mammals in arid ecosystems as well as guidelines for choosing the most appropriate methods for a terrestrial mammal inventory. Survey methods selection and guidelines provided here can allow for effective monitoring and therefore effective and adaptive management and having reliable and repeatable outcomes from surveys. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2021
- Full Text: false
- Date Issued: 2021-04
- Authors: Burt, Chloe
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Biodiversity -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52338 , vital:43591
- Description: A current critical environmental problem is the loss of biodiversity. To allow for adaptive management and effective conservation interventions, reliable data needs to be readily available and effectively collected. To gather reliable data, the most appropriate method must be used. The aim of this thesis was to compare the effectiveness and efficiency of different mammal diversity sampling techniques, including discussing specificities and complementarity of each. I also assessed the limitation of methods in terms of the influence of species traits on detectability. I used standard mammal field methods such as block transects, camera traps, track plates, spotlight surveys, mist nets, acoustic surveys, and live traps for a wide range of mammal taxa, and also included the use of local knowledge in the comparison. I assessed the cost-efficiency of each method by determining the cost per species. The efficiency of each method was assessed by observing when the species accumulation curve reached an asymptote. The effectiveness was determined by the species richness and the taxonomic groups the method detected. My results indicated that block transects were the most efficient and effective method to assess species richness. However, a combination of methods allowed for a more comprehensive survey and my results indicate that block transects and live traps were the best combination. It is important to note, not only the effectiveness and efficiency of methods be assessed, but also their limitations. I therefore also assessed the influence of species traits on the detectability of five methods. The species traits that I tested were body size, diet, activity, and if they lived in groups. On both study areas, body size was the main trait that influenced detectability with most field methods. Diet and activity had varying influence on detectability depending on the method. Group living did not significantly influence detectability. Based on my results, I provide guidelines for choosing the most appropriate survey method for targeted studies on mammals in arid ecosystems as well as guidelines for choosing the most appropriate methods for a terrestrial mammal inventory. Survey methods selection and guidelines provided here can allow for effective monitoring and therefore effective and adaptive management and having reliable and repeatable outcomes from surveys. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2021
- Full Text: false
- Date Issued: 2021-04
An efficient approach for the synthesis of dolutegravir and its analogue exploiting flow chemistry
- Authors: Nqeketo, Sinazo
- Date: 2023-04
- Subjects: HIV (Viruses) – Enzymes –Inhibitors , Antiviral agents -- South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/${Handle} , vital:70635
- Description: Africa has the highest Human Immunodeficiency Virus (HIV) prevalence in the world and has invested heavily in running its HIV programmes and conducting research of medical significance. Despite efforts in combating this disease the production, distribution, cost, and availability of antiretroviral (ARV) generics remains a major problem as they are imported from China and India. Exploring the recently emerged “enabling technique”, namely flow chemistry in the production of APIs has gained a lot of attention. This study was devoted on exploring the application of flow chemistry on the synthesis of a newly approved anti-HIV drug dolutegravir (DTG); an integrase inhibitor with a high genetic barrier to resistance with a daily dosing scheduled compared to other ARVs and its third-generation inhibitor analogue, cabotegravir. Chapter one covers a comprehensive background and literature review of the HIV epidemic, an introduction of antiretroviral therapy as well as detailed dolutegravir and cabotegravir synthesis. A brief introduction of continuous flow technology with its advantages and disadvantages is discussed in this chapter. The efficient seven-step continuous flow procedure afforded dolutegravir and cabotegravir in improved reaction times and yields compared to the traditional batch procedure was demonstrated. The significant advantage of this flow process includes the reduction of the overall reaction time from step one to step seven, from prolonged 68 hours in batch to 34 minutes. The overall yield of each reaction step improved dramatically upon flow optimization. The yields of the second step (selective ester hydrolysis), fourth step (cyclization) and fifth step (amidation) increased from 64 %, 40 % and 33 % in batch to 98 %, 71 % and 100 % yield by HPLC respectively. Other than improved yields and residence times which was aided advantages of microreactor technology including intensive mixing, the flow process is also much better because it is cost effective. Most importantly, a novel process on the formation of pyridinone intermediate using ion-exchange resin catalysts towards the synthesis of dolutegravir and cabotegravir was described in this study , Thesis (PhD) -- Faculty of Science, School of Biomolecular and Chemical Science, 2023
- Full Text:
- Date Issued: 2023-04
- Authors: Nqeketo, Sinazo
- Date: 2023-04
- Subjects: HIV (Viruses) – Enzymes –Inhibitors , Antiviral agents -- South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/${Handle} , vital:70635
- Description: Africa has the highest Human Immunodeficiency Virus (HIV) prevalence in the world and has invested heavily in running its HIV programmes and conducting research of medical significance. Despite efforts in combating this disease the production, distribution, cost, and availability of antiretroviral (ARV) generics remains a major problem as they are imported from China and India. Exploring the recently emerged “enabling technique”, namely flow chemistry in the production of APIs has gained a lot of attention. This study was devoted on exploring the application of flow chemistry on the synthesis of a newly approved anti-HIV drug dolutegravir (DTG); an integrase inhibitor with a high genetic barrier to resistance with a daily dosing scheduled compared to other ARVs and its third-generation inhibitor analogue, cabotegravir. Chapter one covers a comprehensive background and literature review of the HIV epidemic, an introduction of antiretroviral therapy as well as detailed dolutegravir and cabotegravir synthesis. A brief introduction of continuous flow technology with its advantages and disadvantages is discussed in this chapter. The efficient seven-step continuous flow procedure afforded dolutegravir and cabotegravir in improved reaction times and yields compared to the traditional batch procedure was demonstrated. The significant advantage of this flow process includes the reduction of the overall reaction time from step one to step seven, from prolonged 68 hours in batch to 34 minutes. The overall yield of each reaction step improved dramatically upon flow optimization. The yields of the second step (selective ester hydrolysis), fourth step (cyclization) and fifth step (amidation) increased from 64 %, 40 % and 33 % in batch to 98 %, 71 % and 100 % yield by HPLC respectively. Other than improved yields and residence times which was aided advantages of microreactor technology including intensive mixing, the flow process is also much better because it is cost effective. Most importantly, a novel process on the formation of pyridinone intermediate using ion-exchange resin catalysts towards the synthesis of dolutegravir and cabotegravir was described in this study , Thesis (PhD) -- Faculty of Science, School of Biomolecular and Chemical Science, 2023
- Full Text:
- Date Issued: 2023-04
An evaluation of hibiscus sabdariffa gold nanoparticles for the treatment of triple negative breast cancer
- Authors: Reddy, Nireshini
- Date: 2022-12
- Subjects: Breast--Cancer--Treatment--Technological innovations , Nanomedicine – South Africa , Roselle
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/59945 , vital:62697
- Description: Cancer is responsible for the millions of deaths worldwide every year, being ranked as the second leading cause of mortality in the world. Triple negative breast cancer (TNBC) is the most severe type of breast cancer, as it is the most aggressive and difficult to treat. Current treatment methods involve surgery, hormonal-, radiation- and chemotherapy. These are costly and often have severe adverse effects. There has been increasing research in the development of alternative treatment methods to reduce the side effects of cancer therapeutics, as well as the cost. The rapidly growing field of nanotechnology has allowed for the incorporation of several diagnostic, targeting, and therapeutic agents into nanomaterials for cancer treatment. The application of gold nanoparticles (AuNPs) in the diagnosis and treatment of various types of cancers has been widely investigated. AuNPs vary in size, shape, and structure, allowing for the development of diverse formulations for various treatments. The use of green materials, particularly plant material, to synthesise nanomaterials has allowed for the safe, cost-friendly and eco-friendly production of AuNPs that can be used to treat TNBC. The aim of this study was to evaluate the efficiency of green AuNPs synthesised with Hibiscus sabdariffa to treat TNBC in a pilot murine model. Spherical AuNPs were synthesised using an aqueous extract of the calyces of this plant. The AuNPs were characterised using UV-Vis spectrometry, dynamic light scattering, high resolution – transmission electron microscopy, and in vitro stability testing. A cell viability assay showed that these AuNPs exhibited cytotoxicity towards E0771 cells in a dose-dependent manner, where cells treated with the highest concentration of AuNPs (250 µg/mL) exhibited the lowest cell viability (7%). During the in vivo pilot study, C57BL/6 mice were inoculated with TNBC using the E0771 cells. It was found that TNBC had rapidly spread, resulting in metastasis in the liver, as well as omentum and mesentery. This resulted in a number of mice dying; therefore, shortening treatment time of the AuNPs. It is suggested that AuNP treatment may have exacerbated mouse death by promoting ROS production in metastasised tissue, suggesting that AuNP treatment may not be suitable for stage 4 TNBC. Tumor analysis of caspase-3 content showed that the AuNPs exhibited potential pro-apoptotic activity in the tumours, prompting further research into the tumour uptake and apoptotic mechanism of these AuNPs. , Thesis (MSc) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2022
- Full Text:
- Date Issued: 2022-12
- Authors: Reddy, Nireshini
- Date: 2022-12
- Subjects: Breast--Cancer--Treatment--Technological innovations , Nanomedicine – South Africa , Roselle
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/59945 , vital:62697
- Description: Cancer is responsible for the millions of deaths worldwide every year, being ranked as the second leading cause of mortality in the world. Triple negative breast cancer (TNBC) is the most severe type of breast cancer, as it is the most aggressive and difficult to treat. Current treatment methods involve surgery, hormonal-, radiation- and chemotherapy. These are costly and often have severe adverse effects. There has been increasing research in the development of alternative treatment methods to reduce the side effects of cancer therapeutics, as well as the cost. The rapidly growing field of nanotechnology has allowed for the incorporation of several diagnostic, targeting, and therapeutic agents into nanomaterials for cancer treatment. The application of gold nanoparticles (AuNPs) in the diagnosis and treatment of various types of cancers has been widely investigated. AuNPs vary in size, shape, and structure, allowing for the development of diverse formulations for various treatments. The use of green materials, particularly plant material, to synthesise nanomaterials has allowed for the safe, cost-friendly and eco-friendly production of AuNPs that can be used to treat TNBC. The aim of this study was to evaluate the efficiency of green AuNPs synthesised with Hibiscus sabdariffa to treat TNBC in a pilot murine model. Spherical AuNPs were synthesised using an aqueous extract of the calyces of this plant. The AuNPs were characterised using UV-Vis spectrometry, dynamic light scattering, high resolution – transmission electron microscopy, and in vitro stability testing. A cell viability assay showed that these AuNPs exhibited cytotoxicity towards E0771 cells in a dose-dependent manner, where cells treated with the highest concentration of AuNPs (250 µg/mL) exhibited the lowest cell viability (7%). During the in vivo pilot study, C57BL/6 mice were inoculated with TNBC using the E0771 cells. It was found that TNBC had rapidly spread, resulting in metastasis in the liver, as well as omentum and mesentery. This resulted in a number of mice dying; therefore, shortening treatment time of the AuNPs. It is suggested that AuNP treatment may have exacerbated mouse death by promoting ROS production in metastasised tissue, suggesting that AuNP treatment may not be suitable for stage 4 TNBC. Tumor analysis of caspase-3 content showed that the AuNPs exhibited potential pro-apoptotic activity in the tumours, prompting further research into the tumour uptake and apoptotic mechanism of these AuNPs. , Thesis (MSc) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2022
- Full Text:
- Date Issued: 2022-12
An evaluation of the effectiveness of area-based conservation intervention in avoiding biodiversity loss in South Africa
- Authors: Van Straten, Maurice Oswald
- Date: 2023-04
- Subjects: Soil conservation -- South Africa , Livestock farms – South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/61132 , vital:69765
- Description: Habitat degradation, livestock farming, crop cultivation, rangeland overutilization and veld mismanagement are among the factors causing biodiversity loss worldwide. Rangelands in arid and semi-arid environments are no exception, as they are under stress from conversion into cropland and pressure from livestock farming. In these arid areas, rainfall is unpredictable and plant recruitment levels low, resulting in veld rehabilitation being a potentially expensive and time-consuming undertaking for landowners. Landowners implement different rehabilitation methods to increase overall vegetation cover and prevent further soil and vegetation degradation. These rehabilitation methods may include the creation of micro-catchments, mulching, brushpacking, ripping, geotextiles, stone cobbling and erosion control fences, individually or in combination with the addition of reseeding, replanting, and use of manure or fertilizer to supplement land rehabilitation. This study investigated the significance of three rehabilitation methods (hollows, brush packing and a combination of these two methods) on water infiltration rates, soil moisture content, and vegetation canopy cover with associated growth form canopy cover over a period of 17 months (March 2021 to August 2022). This study showed that rehabilitation methods implemented had no significant impact on water infiltration rates and vegetation canopy cover. However, rehabilitation methods had a significant impact on soil moisture content. The use of a hollows is recommended when attempting to increase the soil moisture content percentage when performing rehabilitation. Overall vegetation canopy cover is influenced more by seasonal changes than by the rehabilitation methods implemented. This study indicated that the creation of micro-catchments is an effective rehabilitation method to use in an arid area, as it promotes vegetation establishment and growth. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Science and Management , 2023
- Full Text:
- Date Issued: 2023-04
- Authors: Van Straten, Maurice Oswald
- Date: 2023-04
- Subjects: Soil conservation -- South Africa , Livestock farms – South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/61132 , vital:69765
- Description: Habitat degradation, livestock farming, crop cultivation, rangeland overutilization and veld mismanagement are among the factors causing biodiversity loss worldwide. Rangelands in arid and semi-arid environments are no exception, as they are under stress from conversion into cropland and pressure from livestock farming. In these arid areas, rainfall is unpredictable and plant recruitment levels low, resulting in veld rehabilitation being a potentially expensive and time-consuming undertaking for landowners. Landowners implement different rehabilitation methods to increase overall vegetation cover and prevent further soil and vegetation degradation. These rehabilitation methods may include the creation of micro-catchments, mulching, brushpacking, ripping, geotextiles, stone cobbling and erosion control fences, individually or in combination with the addition of reseeding, replanting, and use of manure or fertilizer to supplement land rehabilitation. This study investigated the significance of three rehabilitation methods (hollows, brush packing and a combination of these two methods) on water infiltration rates, soil moisture content, and vegetation canopy cover with associated growth form canopy cover over a period of 17 months (March 2021 to August 2022). This study showed that rehabilitation methods implemented had no significant impact on water infiltration rates and vegetation canopy cover. However, rehabilitation methods had a significant impact on soil moisture content. The use of a hollows is recommended when attempting to increase the soil moisture content percentage when performing rehabilitation. Overall vegetation canopy cover is influenced more by seasonal changes than by the rehabilitation methods implemented. This study indicated that the creation of micro-catchments is an effective rehabilitation method to use in an arid area, as it promotes vegetation establishment and growth. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Science and Management , 2023
- Full Text:
- Date Issued: 2023-04
An evaluation of the effectiveness of area-based conservation interventions in avoiding biodiversity loss in South Africa
- Authors: Von Staden, Lize
- Date: 2023-04
- Subjects: Environmental policy , Conservation of natural resources -- Government policy -- South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/61115 , vital:69762
- Description: Counterfactual impact evaluation studies form an important evidence base for the effectiveness of conservation projects, programs, and policies (collectively referred to as conservation interventions). In South Africa, counterfactual impact evaluation methods have rarely been applied to local conservation interventions, and therefore evidence for the effectiveness of key strategic national conservation approaches is lacking. This study evaluated three area-based interventions that together aim to avoid the loss of areas most important for the persistence of biodiversity in the terrestrial realm as evidence towards the effectiveness of South Africa’s landscape approach to biodiversity conservation. The first intervention, South Africa’s National Protected Area Expansion Strategy (NPAES), set ambitious targets to double the extent of South Africa’s protected area network while ensuring that the expansion preferentially occurs in areas of under-represented biodiversity. The strategy was evaluated in terms of its effectiveness in guiding protected area expansion towards more equitable representation of South Africa’s biodiversity through an assessment of changes in indicators of protected area expansion decision-making before and after the implementation of the strategy. The second intervention is the use of maps of biodiversity priorities to guide land use change decisions outside protected areas. Impact was evaluated as avoided loss of Critical Biodiversity Areas (CBAs), which need to remain in a natural condition to meet in situ conservation targets for species, ecosystems, and ecological processes. Avoided loss in CBAs was benchmarked against avoided loss in protected areas, to contextualize the effectiveness of land use planning as a conservation intervention. Lastly, the effectiveness of stricter land use regulations for threatened ecosystems to reduce land conversion pressure on these ecosystems was evaluated. Key findings were that protected areas are highly effective conservation interventions where they can be implemented, but their capacity for conservation impact is limited by severe constraints on strategic expansion. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-04
- Authors: Von Staden, Lize
- Date: 2023-04
- Subjects: Environmental policy , Conservation of natural resources -- Government policy -- South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/61115 , vital:69762
- Description: Counterfactual impact evaluation studies form an important evidence base for the effectiveness of conservation projects, programs, and policies (collectively referred to as conservation interventions). In South Africa, counterfactual impact evaluation methods have rarely been applied to local conservation interventions, and therefore evidence for the effectiveness of key strategic national conservation approaches is lacking. This study evaluated three area-based interventions that together aim to avoid the loss of areas most important for the persistence of biodiversity in the terrestrial realm as evidence towards the effectiveness of South Africa’s landscape approach to biodiversity conservation. The first intervention, South Africa’s National Protected Area Expansion Strategy (NPAES), set ambitious targets to double the extent of South Africa’s protected area network while ensuring that the expansion preferentially occurs in areas of under-represented biodiversity. The strategy was evaluated in terms of its effectiveness in guiding protected area expansion towards more equitable representation of South Africa’s biodiversity through an assessment of changes in indicators of protected area expansion decision-making before and after the implementation of the strategy. The second intervention is the use of maps of biodiversity priorities to guide land use change decisions outside protected areas. Impact was evaluated as avoided loss of Critical Biodiversity Areas (CBAs), which need to remain in a natural condition to meet in situ conservation targets for species, ecosystems, and ecological processes. Avoided loss in CBAs was benchmarked against avoided loss in protected areas, to contextualize the effectiveness of land use planning as a conservation intervention. Lastly, the effectiveness of stricter land use regulations for threatened ecosystems to reduce land conversion pressure on these ecosystems was evaluated. Key findings were that protected areas are highly effective conservation interventions where they can be implemented, but their capacity for conservation impact is limited by severe constraints on strategic expansion. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-04
An evolutionary algorithm approach to ecological optimal control problems
- Authors: Westcott, Amy-Rose
- Date: 2022-04
- Subjects: Mathematical optimization -- South africa , Evolutionary programming (Computer science)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55544 , vital:52812
- Description: There are several challenges associated with applying conventional (hereafter classic) optimal control (OC) methods to ecological optimal control problems (OCPs). Conditions required by these methods, including differentiability and convexity, for example, are not always met, and ecological problems do not always adhere to solvable OCP formulations. Moreover, mathematically optimal solutions do not always translate to optimal ecological strategies in practice. Despite this, alternative OC approaches are relatively under-explored. Evolutionary algorithms (EAs) circumvent many of the complex aspects of classic OC methods and have been successfully applied to diverse OCPs. Nevertheless, EAs have sel dom been applied to ecological OCPs. The viability of an EA approach to ecological OCPs was therefore investigated in the current study, facilitated by four case studies of increasing complexity and a genetic algorithm (GA) as a representative EA approach. To ascertain the accuracy of a GA approach, comparisons between a GA and classic OC methods were conducted in the first three case studies. The GA generated near-optima in these comparisons, comparable to the corresponding classical solutions, whilst avoiding non-trivial mathematical theory. Supported by these results, an unconventional OCP, that arguably cannot be solved using classic OC methods, was formulated in the fourth case study, and solved using a GA approach. The resulting solution was feasible and further conformed with strategies found to be successful in practice. Additionally, the GA approach was rela tively simple to apply in all case studies. These collective outcomes of demonstrated the viability of a GA as an OC method in eco logical OCPs, thereby supporting the use of an EA approach as an alternative to classic OC methods in ecological OCPs. The feasibility of an EA approach to atypical OCPs was further demonstrated, which may act to increase realism in OC applications. Further investigation in this regard is thus warranted by this study. , Thesis (MS) -- Faculty of Science, Mathematics and Applied Mathematics, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Westcott, Amy-Rose
- Date: 2022-04
- Subjects: Mathematical optimization -- South africa , Evolutionary programming (Computer science)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55544 , vital:52812
- Description: There are several challenges associated with applying conventional (hereafter classic) optimal control (OC) methods to ecological optimal control problems (OCPs). Conditions required by these methods, including differentiability and convexity, for example, are not always met, and ecological problems do not always adhere to solvable OCP formulations. Moreover, mathematically optimal solutions do not always translate to optimal ecological strategies in practice. Despite this, alternative OC approaches are relatively under-explored. Evolutionary algorithms (EAs) circumvent many of the complex aspects of classic OC methods and have been successfully applied to diverse OCPs. Nevertheless, EAs have sel dom been applied to ecological OCPs. The viability of an EA approach to ecological OCPs was therefore investigated in the current study, facilitated by four case studies of increasing complexity and a genetic algorithm (GA) as a representative EA approach. To ascertain the accuracy of a GA approach, comparisons between a GA and classic OC methods were conducted in the first three case studies. The GA generated near-optima in these comparisons, comparable to the corresponding classical solutions, whilst avoiding non-trivial mathematical theory. Supported by these results, an unconventional OCP, that arguably cannot be solved using classic OC methods, was formulated in the fourth case study, and solved using a GA approach. The resulting solution was feasible and further conformed with strategies found to be successful in practice. Additionally, the GA approach was rela tively simple to apply in all case studies. These collective outcomes of demonstrated the viability of a GA as an OC method in eco logical OCPs, thereby supporting the use of an EA approach as an alternative to classic OC methods in ecological OCPs. The feasibility of an EA approach to atypical OCPs was further demonstrated, which may act to increase realism in OC applications. Further investigation in this regard is thus warranted by this study. , Thesis (MS) -- Faculty of Science, Mathematics and Applied Mathematics, 2022
- Full Text:
- Date Issued: 2022-04
An exploration of the Participatory Guarantee System (PGS) facilitating the growth and certification of small-scale organic farmers: Giyani, Garden Route and Overberg case studies
- Authors: Mashele,N’wa-Jama
- Date: 2023-04
- Subjects: Organic farming – Case studies --South Africa , Organic farming research
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/60741 , vital:66574
- Description: In this study, I evaluated the Participatory Guarantee System (PGS) as a framework to support the growth and certification of small-scale organic farmers. I used the interpretivism and constructivism lenses to understand the PGS from the perspective of members of three PGS groups. The research was qualitative, treating the three PGS groups as case studies. I collected data using focus groups, semi-structured interviews, questionnaires, field notes and observations. The theoretical frameworks that guided the research and data analysis were Socio-ecological Systems (SES) based principles and the Multi-Level-Perspective (MLP) framework. The data were analysed using Atlas.ti content analysis software. The key results were grouped into four themes: capacity; market and logistics; learning process; and disturbance, shock and stress. The theme of ‘capacity’ dealt with the functioning of a PGS, where three categories were identified: group composition and capacity; resource limitations and institutional support; marketing and consumer education. The more diversity in age, education and culture of PGS stakeholders, the better performance and chances of continuity and propagation. PGS has limited capacity partly due to its voluntary nature and infancy. It needs institutional support to grow and be useful for members. Department of Agriculture extension officers knew little about organic farming, thus limiting their engagement and assistance to such farmers. The theme of ‘market and logistics’ looked at the various factors that influence the farmers’ market reach. The perception from the members was that there was minimal consumer awareness about organic agriculture and the PGS. The marketing of organic produce relied largely on the individual farmer’s efforts and ability to search for and secure markets. The theme of the ‘learning process’ was categorised into learning and knowledge exchange. Members of the PGS groups highly regarded the invaluable knowledge shared through farm visits and online platforms, such as their WhatsApp groups. This knowledge improved and informed their farming techniques and led to the growth of v their skill base and experimentation. They viewed the way knowledge was exchanged as non-threatening and highly useful. The fourth theme of ‘disturbance, shock and stress’ dealt with the effects of COVID19. The three groups were all affected by lockdown restrictions (at the time of data collection) and were initially cut off from their usual markets. This led to a loss of income, loss of farm staff and a loss of the desired growth of the farms. The group’s diverse farming practices bolstered their resilience, enabling them to adapt and try alternative marketing strategies. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2023
- Full Text:
- Date Issued: 2023-04
- Authors: Mashele,N’wa-Jama
- Date: 2023-04
- Subjects: Organic farming – Case studies --South Africa , Organic farming research
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/60741 , vital:66574
- Description: In this study, I evaluated the Participatory Guarantee System (PGS) as a framework to support the growth and certification of small-scale organic farmers. I used the interpretivism and constructivism lenses to understand the PGS from the perspective of members of three PGS groups. The research was qualitative, treating the three PGS groups as case studies. I collected data using focus groups, semi-structured interviews, questionnaires, field notes and observations. The theoretical frameworks that guided the research and data analysis were Socio-ecological Systems (SES) based principles and the Multi-Level-Perspective (MLP) framework. The data were analysed using Atlas.ti content analysis software. The key results were grouped into four themes: capacity; market and logistics; learning process; and disturbance, shock and stress. The theme of ‘capacity’ dealt with the functioning of a PGS, where three categories were identified: group composition and capacity; resource limitations and institutional support; marketing and consumer education. The more diversity in age, education and culture of PGS stakeholders, the better performance and chances of continuity and propagation. PGS has limited capacity partly due to its voluntary nature and infancy. It needs institutional support to grow and be useful for members. Department of Agriculture extension officers knew little about organic farming, thus limiting their engagement and assistance to such farmers. The theme of ‘market and logistics’ looked at the various factors that influence the farmers’ market reach. The perception from the members was that there was minimal consumer awareness about organic agriculture and the PGS. The marketing of organic produce relied largely on the individual farmer’s efforts and ability to search for and secure markets. The theme of the ‘learning process’ was categorised into learning and knowledge exchange. Members of the PGS groups highly regarded the invaluable knowledge shared through farm visits and online platforms, such as their WhatsApp groups. This knowledge improved and informed their farming techniques and led to the growth of v their skill base and experimentation. They viewed the way knowledge was exchanged as non-threatening and highly useful. The fourth theme of ‘disturbance, shock and stress’ dealt with the effects of COVID19. The three groups were all affected by lockdown restrictions (at the time of data collection) and were initially cut off from their usual markets. This led to a loss of income, loss of farm staff and a loss of the desired growth of the farms. The group’s diverse farming practices bolstered their resilience, enabling them to adapt and try alternative marketing strategies. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2023
- Full Text:
- Date Issued: 2023-04
An investigation into the effects of nano-carbons on the negative electrode morphology of lead acid batteries under high rate partial state of capacity cycling
- Authors: Bolo, Lukanyo
- Date: 2021-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/53324 , vital:45132
- Description: New technological developments in the field of Hybrid Electric Vehicles (HEV’s), vehicle stop-start applications and electrical power utility devices have brought about new demands on the use of energy storage devices such as the Pb-acid battery. These applications require a new understanding and research into the material chemistry of the battery where it has to functionin a Partial State of Capacity Cycling (PSoCC) or High Rate Partial State of Capacity Cycling (HRPSoCC)duty. The Pb-acid battery is well known for its use in the automotive industry where it had worked for decades as a typical Starter, Lighting and Ignition (SLI) power source. However, the conventional Pb-acid battery is not suitable for the new types of vehicle demands and applications. When the Pb-lead acid battery is subjected to PSoCC conditions, very quickly excessive amount of non-conducting PbSO4crystals are formed on the negative plates of the battery that then drastically reduce its useful life in application. Over the years, researchers have shown that the small addition of certain carbon types to the negative plate active material (NAM) during battery manufacturing can reduce the sulfation effect thereby increasing its use the modern vehicle applications. This study investigated industrial manufactured cells that contained up to 0.5 % by weight two types of carbons in the NAM. These were compared to standard built cells in terms of their standard achievable capacities at various rates, their Cold Cranking Ability (CCA), their Dynamic Charge Acceptance (DCA) and a simplified PSoCC test. The carbons were classified as an activated carbon and a carbon nano-fiber and were included as a dry weight additive during the standard paste manufacturing process of the negative plate. Cells were built with a 9-plate configuration using standard expanded grid positive plates with a nominal rated capacity of 36 Ah. The cells were formed and subjected to a number of electrochemical tests, of which selected negative plates were then studied using Scanning Electron Microscopy (SEM) and Electrochemical in-situ Atomic Force Microscopy (EC-AFM). The microscopic study was then used to try and relate the observed material characteristics of the NAM with the carbons to the electrochemical results observed when testing a built cell. , Thesis (MA) --Faculty of Science, School of Biomolecular and Chemical Sciences, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Bolo, Lukanyo
- Date: 2021-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/53324 , vital:45132
- Description: New technological developments in the field of Hybrid Electric Vehicles (HEV’s), vehicle stop-start applications and electrical power utility devices have brought about new demands on the use of energy storage devices such as the Pb-acid battery. These applications require a new understanding and research into the material chemistry of the battery where it has to functionin a Partial State of Capacity Cycling (PSoCC) or High Rate Partial State of Capacity Cycling (HRPSoCC)duty. The Pb-acid battery is well known for its use in the automotive industry where it had worked for decades as a typical Starter, Lighting and Ignition (SLI) power source. However, the conventional Pb-acid battery is not suitable for the new types of vehicle demands and applications. When the Pb-lead acid battery is subjected to PSoCC conditions, very quickly excessive amount of non-conducting PbSO4crystals are formed on the negative plates of the battery that then drastically reduce its useful life in application. Over the years, researchers have shown that the small addition of certain carbon types to the negative plate active material (NAM) during battery manufacturing can reduce the sulfation effect thereby increasing its use the modern vehicle applications. This study investigated industrial manufactured cells that contained up to 0.5 % by weight two types of carbons in the NAM. These were compared to standard built cells in terms of their standard achievable capacities at various rates, their Cold Cranking Ability (CCA), their Dynamic Charge Acceptance (DCA) and a simplified PSoCC test. The carbons were classified as an activated carbon and a carbon nano-fiber and were included as a dry weight additive during the standard paste manufacturing process of the negative plate. Cells were built with a 9-plate configuration using standard expanded grid positive plates with a nominal rated capacity of 36 Ah. The cells were formed and subjected to a number of electrochemical tests, of which selected negative plates were then studied using Scanning Electron Microscopy (SEM) and Electrochemical in-situ Atomic Force Microscopy (EC-AFM). The microscopic study was then used to try and relate the observed material characteristics of the NAM with the carbons to the electrochemical results observed when testing a built cell. , Thesis (MA) --Faculty of Science, School of Biomolecular and Chemical Sciences, 2021
- Full Text:
- Date Issued: 2021-04