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
An aesthetic exploration of skin as the abject other
- Knickelbein, Jonel, Wentzel, Andrieta
- Authors: Knickelbein, Jonel , Wentzel, Andrieta
- 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/10948/55341 , vital:51913
- Description: The purpose of this dissertation is to explore the notion of skin, its functions, and dysfunctions as the basis for the conceptual as well as theoretical output of this work. The problem statement aims to establish whether cathartic relief can be achieved through the process of visualizing skin as the abject other. Every human and animal is born with skin. The epidermis is the outermost of three layers that make up the skin. This layer provides a barrier to infection from environmental pathogens and regulates the amount of water released from the body into the atmosphere through trans epidermal water loss (Bouwstra, 2003:34). Although the human skin serves as a protective barrier, the skin itself can be a source of physical as well as emotional pain. I was born with Epidermolysis Bullosa (EB), a rare and genetic skin condition that results in extensive blistering and wounding of the skin caused by mechanical trauma. The process of friction, wounding and healing has been a part of my physical being and daily affairs since I can remember. According to Cervero, ―Pain is our most powerful emotion, an essential learning tool, a major factor in our relationship with the world, and the source of much of our social behavior‖ (2012:34).I believe that my personal experience with EB has affected how I view the functions and importance of skin. In this study I explore the purposes and functions of skin through both a physical and psychological lense I also investigate the role skin plays in forming identity. The works of artists such as Frida Kahlo, Eva Hesse and Alina Szapocznikow are carefully considered in understanding different approaches and mediums used in engaging with the experience of catharsis. Investigations are made into theories on Abjection, the Skin-Ego, Materiality and Catharsis in order to sufficiently inform and shape the outcomes of the creative process. The creative and research processes have resulted in the body of artwork, entitled Skin- deep: transforming dysfunction into function, which is presented as a narrative installation and exhibition of abstract sculptural work. Ultimately, the body of work and research attempts to validate that the notion of skin (as the abject other skin) can be artistically explored to achieve cathartic relief. , Thesis (MA) -- Faculty of Humanities, School of Visual and Performing Arts, 2022
- Full Text: false
- Date Issued: 2022-04
- Authors: Knickelbein, Jonel , Wentzel, Andrieta
- 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/10948/55341 , vital:51913
- Description: The purpose of this dissertation is to explore the notion of skin, its functions, and dysfunctions as the basis for the conceptual as well as theoretical output of this work. The problem statement aims to establish whether cathartic relief can be achieved through the process of visualizing skin as the abject other. Every human and animal is born with skin. The epidermis is the outermost of three layers that make up the skin. This layer provides a barrier to infection from environmental pathogens and regulates the amount of water released from the body into the atmosphere through trans epidermal water loss (Bouwstra, 2003:34). Although the human skin serves as a protective barrier, the skin itself can be a source of physical as well as emotional pain. I was born with Epidermolysis Bullosa (EB), a rare and genetic skin condition that results in extensive blistering and wounding of the skin caused by mechanical trauma. The process of friction, wounding and healing has been a part of my physical being and daily affairs since I can remember. According to Cervero, ―Pain is our most powerful emotion, an essential learning tool, a major factor in our relationship with the world, and the source of much of our social behavior‖ (2012:34).I believe that my personal experience with EB has affected how I view the functions and importance of skin. In this study I explore the purposes and functions of skin through both a physical and psychological lense I also investigate the role skin plays in forming identity. The works of artists such as Frida Kahlo, Eva Hesse and Alina Szapocznikow are carefully considered in understanding different approaches and mediums used in engaging with the experience of catharsis. Investigations are made into theories on Abjection, the Skin-Ego, Materiality and Catharsis in order to sufficiently inform and shape the outcomes of the creative process. The creative and research processes have resulted in the body of artwork, entitled Skin- deep: transforming dysfunction into function, which is presented as a narrative installation and exhibition of abstract sculptural work. Ultimately, the body of work and research attempts to validate that the notion of skin (as the abject other skin) can be artistically explored to achieve cathartic relief. , Thesis (MA) -- Faculty of Humanities, School of Visual and Performing Arts, 2022
- Full Text: false
- Date Issued: 2022-04
An investigating of the causes of conflict in the department of employment and labour in Port Elizabeth
- Authors: Dlwati, Siphesihle
- 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/10948/55346 , vital:51914
- Description: The public sector in South Africa accounts for a huge amount of the public service jobs and it has been learnt that there is also a considerable amount of dysfunctional conflict that affects the public sector. The main aim of this study is to investigate the causes of conflict in the public sector, with specific reference to the department of Employment and Labour, in Port Elizabeth. The research objectives were as follows; firstly, to investigate the causes of conflict or potential conflict at the department of Employment and Labour in Port Elizabeth. Secondly, the research sought to ascertain government employees’ approach to conflict and how it affects their performance (management and subordinates) with specific reference to the department of Employment and Labour, in Port Elizabeth. Thirdly, the research also sought to come up with the recommendations with the view to address conflict or what might be causing conflict at the department of Employment and Labour in Port Elizabeth. Workplace conflict was used in this study as a conceptual framework to understand conflict in the department of Employment and Labour, in Port Elizabeth. The research has followed a qualitative approach to gather data. Using a purposive selection sampling technique, 12 semi-structured interviews were conducted with employees of the department of Employment and Labour, in Port Elizabeth. Ethical considerations were adhered to throughout the course of the study. The findings of this study have revealed that lack of consultation or lack of an inclusive or participative approach in dealing with matters is regarded as the main cause of conflict within the studied organisation. The organisations lack conflict management skills. This study can be of benefit to the organisation, in that its recommendations can assist the organisation place more attention on improving its conflict management skills, which may help reduce the negative impacts of unmanaged conflicts. , Thesis (MA) -- Faculty of Humanities, School of Governmental and Social Sciences, 2022
- Full Text: false
- Date Issued: 2022-04
- Authors: Dlwati, Siphesihle
- 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/10948/55346 , vital:51914
- Description: The public sector in South Africa accounts for a huge amount of the public service jobs and it has been learnt that there is also a considerable amount of dysfunctional conflict that affects the public sector. The main aim of this study is to investigate the causes of conflict in the public sector, with specific reference to the department of Employment and Labour, in Port Elizabeth. The research objectives were as follows; firstly, to investigate the causes of conflict or potential conflict at the department of Employment and Labour in Port Elizabeth. Secondly, the research sought to ascertain government employees’ approach to conflict and how it affects their performance (management and subordinates) with specific reference to the department of Employment and Labour, in Port Elizabeth. Thirdly, the research also sought to come up with the recommendations with the view to address conflict or what might be causing conflict at the department of Employment and Labour in Port Elizabeth. Workplace conflict was used in this study as a conceptual framework to understand conflict in the department of Employment and Labour, in Port Elizabeth. The research has followed a qualitative approach to gather data. Using a purposive selection sampling technique, 12 semi-structured interviews were conducted with employees of the department of Employment and Labour, in Port Elizabeth. Ethical considerations were adhered to throughout the course of the study. The findings of this study have revealed that lack of consultation or lack of an inclusive or participative approach in dealing with matters is regarded as the main cause of conflict within the studied organisation. The organisations lack conflict management skills. This study can be of benefit to the organisation, in that its recommendations can assist the organisation place more attention on improving its conflict management skills, which may help reduce the negative impacts of unmanaged conflicts. , Thesis (MA) -- Faculty of Humanities, School of Governmental and Social Sciences, 2022
- Full Text: false
- Date Issued: 2022-04
Classification and clustering based methods for outlier detection of solar resource data
- Authors: Abrahams, Waldo
- 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/10948/55423 , vital:51996
- Description: Almost 90% of the primary global energy demand is serviced from the burning of fossil fuels (Abas, Kalair & Khan, 2015). Owing to the detrimental environmental impact of this, a global energy transition to the use of renewable energy, including solar energy, is needed (Gielen et al., 2019). An important aspect that inhibits the growth of solar energy is accurate solar resource data. Such data is needed because knowledge of the future reliability and quality of energy production is required to analyse a system’s performance and determine financial implications (Sengupta et al., 2017). Existing methods used to detect outliers in solar resource data do not efficiently identify outliers and an accurate and robust approach is required (Eastwood, 2019). Using simulated and real-world data, this study investigates the use of several classification methods, along with a two-stage clustering-classification approach to accurately identify outliers in solar resource data. The Treebag method proves to be an adequate outlier detection method for solar resource data. , Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Abrahams, Waldo
- 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/10948/55423 , vital:51996
- Description: Almost 90% of the primary global energy demand is serviced from the burning of fossil fuels (Abas, Kalair & Khan, 2015). Owing to the detrimental environmental impact of this, a global energy transition to the use of renewable energy, including solar energy, is needed (Gielen et al., 2019). An important aspect that inhibits the growth of solar energy is accurate solar resource data. Such data is needed because knowledge of the future reliability and quality of energy production is required to analyse a system’s performance and determine financial implications (Sengupta et al., 2017). Existing methods used to detect outliers in solar resource data do not efficiently identify outliers and an accurate and robust approach is required (Eastwood, 2019). Using simulated and real-world data, this study investigates the use of several classification methods, along with a two-stage clustering-classification approach to accurately identify outliers in solar resource data. The Treebag method proves to be an adequate outlier detection method for solar resource data. , Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2022
- Full Text:
- Date Issued: 2022-04
Effect of fire severity on Afrotemperate forest tree survival
- Authors: Giddey, Brandon Louis
- 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/10948/55385 , vital:51988
- Description: Weather patterns have changed globally with increased fire danger weather conditions, along with poor management and fire suppression, likely contributing to the increase in prevalence of large wildfires. Ecosystems such as temperate broadleaved forests, where fire is limited by climatic conditions, are particularly at risk of altered fire regimes related to climate change. It is thus important to monitor the effects of fire in these ecosystems. Satellite remote sensing is a cost-effective way to assess spatial variability of fire effects on a landscape scale and has become an increasingly used tool for studying fire severity. In the southern Cape of South Africa during October-November 2018, a large wildfire burnt patches of Southern Cape Afrotemperate Forest (hereafter ‘Afrotemperate forest’). This provided an opportunity to investigate the accuracy of a satellite index for fire severity and the effect of fire on Afrotemperate forest survival. The first objective was to verify through field observations the accuracy of the differenced Normalised Burn Ratio (dNBR) as an index of fire severity derived from Sentinel 2 images in Afrotemperate forest. The second objective was to investigate the effect of fire severity and tree size on the post-fire survival of Afrotemperate forest tree species. For the first objective, stem fire severity, estimated from observed damage to the main stem, was recorded for 1 648 trees in 87 plots and linear regression used to test whether the observed measure of fire severity was related to dNBR. For the second objective, stem fire severity and tree survival 19-24 months post-fire were recorded for 40 species and 1 378 trees in 88 plots. Trees were considered to have survived if they resprouted from the main stem or had green foliage in the canopy. The survival response was assessed in relation to stem fire severity and tree size for all trees collectively and for 10 species (with sample size > 40) individually, using logistic regression. A strong linear relationship between dNBR and stem fire severity (r2 = 0.69, p < 0.001) confirmed the accuracy of dNBR as a measure of fire severity in Afrotemperate forest. In the fire investigated, 4 628 ha of Afrotemperate forest burnt of which 67% burnt at low severity, 21% at medium severity and 12% at high severity. The dNBR values associated with fire severity categories were comparable between Afrotemperate and North American forests, suggesting that dNBR values are relatively standard across forest types. Information on the distribution of fire severity facilitates investigation of further questions regarding past and future fire regimes and the fire ecology of Afrotemperate forest. The post-fire survival rate of Afrotemperate forest trees was 45% which is comparable to that in coniferous forests of North America but lower than that in temperate forests of Australia and Portugal and the neighbouring dune thicket which shares several species with Afrotemperate forest. Fire severity had a significant negative effect on survival and tree size a significant positive effect. Total variance explained by the model (for species collectively) was 40.8%, of which fire severity and tree size combined explained 13.2%, and species as random factor, 27.6%. Respective tree species showed differential survival responses – four species showed high survival (> 60% of individuals), while five species showed low survival (< 40%). This study was the first post-fire assessment of the resprouting ability of Afrotemperate forest trees and a third of the trees surveyed (for species collectively) resprouted from the stem. This suggested that resprouting from the stem is a primary means of post-fire recovery in Afrotemperate forest trees, in contrast with previous assertions that several common canopy species, including Podocarpus latifolius, Afrocarpus falcatus, Scutia myrtina, Scolopia mundii and Rapanea melanophloeos, are unable to resprout. Varying resilience to fire among species supports previous suggestions that fire affects species’ composition and diversity in these forests and calls for careful management of fire regimes in the face of global change. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2022
- Full Text: false
- Date Issued: 2022-04
- Authors: Giddey, Brandon Louis
- 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/10948/55385 , vital:51988
- Description: Weather patterns have changed globally with increased fire danger weather conditions, along with poor management and fire suppression, likely contributing to the increase in prevalence of large wildfires. Ecosystems such as temperate broadleaved forests, where fire is limited by climatic conditions, are particularly at risk of altered fire regimes related to climate change. It is thus important to monitor the effects of fire in these ecosystems. Satellite remote sensing is a cost-effective way to assess spatial variability of fire effects on a landscape scale and has become an increasingly used tool for studying fire severity. In the southern Cape of South Africa during October-November 2018, a large wildfire burnt patches of Southern Cape Afrotemperate Forest (hereafter ‘Afrotemperate forest’). This provided an opportunity to investigate the accuracy of a satellite index for fire severity and the effect of fire on Afrotemperate forest survival. The first objective was to verify through field observations the accuracy of the differenced Normalised Burn Ratio (dNBR) as an index of fire severity derived from Sentinel 2 images in Afrotemperate forest. The second objective was to investigate the effect of fire severity and tree size on the post-fire survival of Afrotemperate forest tree species. For the first objective, stem fire severity, estimated from observed damage to the main stem, was recorded for 1 648 trees in 87 plots and linear regression used to test whether the observed measure of fire severity was related to dNBR. For the second objective, stem fire severity and tree survival 19-24 months post-fire were recorded for 40 species and 1 378 trees in 88 plots. Trees were considered to have survived if they resprouted from the main stem or had green foliage in the canopy. The survival response was assessed in relation to stem fire severity and tree size for all trees collectively and for 10 species (with sample size > 40) individually, using logistic regression. A strong linear relationship between dNBR and stem fire severity (r2 = 0.69, p < 0.001) confirmed the accuracy of dNBR as a measure of fire severity in Afrotemperate forest. In the fire investigated, 4 628 ha of Afrotemperate forest burnt of which 67% burnt at low severity, 21% at medium severity and 12% at high severity. The dNBR values associated with fire severity categories were comparable between Afrotemperate and North American forests, suggesting that dNBR values are relatively standard across forest types. Information on the distribution of fire severity facilitates investigation of further questions regarding past and future fire regimes and the fire ecology of Afrotemperate forest. The post-fire survival rate of Afrotemperate forest trees was 45% which is comparable to that in coniferous forests of North America but lower than that in temperate forests of Australia and Portugal and the neighbouring dune thicket which shares several species with Afrotemperate forest. Fire severity had a significant negative effect on survival and tree size a significant positive effect. Total variance explained by the model (for species collectively) was 40.8%, of which fire severity and tree size combined explained 13.2%, and species as random factor, 27.6%. Respective tree species showed differential survival responses – four species showed high survival (> 60% of individuals), while five species showed low survival (< 40%). This study was the first post-fire assessment of the resprouting ability of Afrotemperate forest trees and a third of the trees surveyed (for species collectively) resprouted from the stem. This suggested that resprouting from the stem is a primary means of post-fire recovery in Afrotemperate forest trees, in contrast with previous assertions that several common canopy species, including Podocarpus latifolius, Afrocarpus falcatus, Scutia myrtina, Scolopia mundii and Rapanea melanophloeos, are unable to resprout. Varying resilience to fire among species supports previous suggestions that fire affects species’ composition and diversity in these forests and calls for careful management of fire regimes in the face of global change. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2022
- Full Text: false
- Date Issued: 2022-04
Encapsulation of flame retardants for lithium-ion battery safety
- Authors: Ntombela, Nompilo Princess
- 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/10948/55412 , vital:51993
- Description: Lithium-ion technology takes the lead in electric mobility systems, resulting in an increase in the global demand for Li-ion batteries; however, these batteries are associated with numerous safety concerns. Additionally, there are high costs, high energy and power issues which are some of its key limitations. Research efforts are focused on overcoming these obstacles, with different approaches being explored, such as the investigation of more stable salts, modification of active materials and organic solvents, and the use of electrolyte additives. This study focused specifically on electrolyte additives since the electrolyte is one of the most unstable components of the battery. The electrolyte’s decomposition is one of the reactions that occur inside a battery, which may occur due to overcharging or due to an internal short circuit, amongst others. The electrolyte’s decomposition occurs at the early stages of the thermal runaway process and forms part of the reactions that lead to fires and explosions. Thus, this research aims to develop suitable electrolyte additives to improve the safety aspects of Li-ion batteries. Flame retardant additives show great promise in reducing the flammability of the electrolyte in Li-ion batteries, since they serve to suppress the chemical reactions associated with battery ignition. They retard the fires by scavenging the active radical species formed during the decomposition reaction. In this study, the use of flame retardants was investigated. Flame retardant additives have shown to have flame impeding properties inside a battery; however, their direct addition to the electrolyte tends to cause adverse effects on the ionic conductivity and electrochemical performance of the cells. This study investigated an alternative option - the option to microencapsulate such additives into a neutral compound to ensure that the flame retardant has minimal/no effect on the performance of the battery. This investigation looked at tris(2-butoxyethyl) phosphate (TBP) and bis(2,2,2-trifluoroethyl) methylphosphonate (BFP) as flame retardant additives for the electrolyte. The TBP and BFP flame retardants were microencapsulated in poly(urea formaldehyde) (PUF) coating material via in situ polymerization method. The capsules were characterized using various analytical techniques - to prove it was successfully encapsulated. Electrochemical studies were further done on the capsules and neat flame retardants inside a coin cell. Self-extinguishing time (SET), which is the flammability test, proved that the additives have flame retarding abilities. Opto-digital microscopy (DSX) and scanning electron microscopy (SEM) did confirm the spherical shape of the microcapsules, where SEM also showed the smooth outer layer of the microcapsules and its hollow inner side. Fourier transform infrared spectroscopy (FTIR) proved the presence of the TBP and BFP inside the PUF resin by showing that the chemical composition of microcapsules consisted of both the PUF and flame retardant additives. Simultaneous DSC-TGA (DST) was also performed which showed that the microcapsules were stable before 200 °C, which indicates it would not decompose before the thermal runaway events are occurring. TGA analysis did show that the microcapsules underwent multiple decomposition steps upon heating. Additionally, 31P nuclear magnetic resonance (NMR) was used to quantify the amount of flame retardants additives encapsulated inside PUF shell, and also confirmed the stability of the microcapsules for one month in the electrolyte and at temperatures up to 200 °C. The ionic conductivity was vastly decreased when the flame retardants were added directly to the electrolyte. However, adding the flame retardants in a form of capsules had minimal effect on the ionic conductivity. The cycle capacities of the capsules were also improved when the capsules were added to the cell compared to that of neat flame retardants. The same effect was also noticed when doing Electrochemical Impedance Spectroscopy (EIS). This shows that microencapsulation improves the resistance of the cell caused by the flame retardant in comparison to when added directly to the electrolyte of the cell. , Thesis (MSC) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Ntombela, Nompilo Princess
- 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/10948/55412 , vital:51993
- Description: Lithium-ion technology takes the lead in electric mobility systems, resulting in an increase in the global demand for Li-ion batteries; however, these batteries are associated with numerous safety concerns. Additionally, there are high costs, high energy and power issues which are some of its key limitations. Research efforts are focused on overcoming these obstacles, with different approaches being explored, such as the investigation of more stable salts, modification of active materials and organic solvents, and the use of electrolyte additives. This study focused specifically on electrolyte additives since the electrolyte is one of the most unstable components of the battery. The electrolyte’s decomposition is one of the reactions that occur inside a battery, which may occur due to overcharging or due to an internal short circuit, amongst others. The electrolyte’s decomposition occurs at the early stages of the thermal runaway process and forms part of the reactions that lead to fires and explosions. Thus, this research aims to develop suitable electrolyte additives to improve the safety aspects of Li-ion batteries. Flame retardant additives show great promise in reducing the flammability of the electrolyte in Li-ion batteries, since they serve to suppress the chemical reactions associated with battery ignition. They retard the fires by scavenging the active radical species formed during the decomposition reaction. In this study, the use of flame retardants was investigated. Flame retardant additives have shown to have flame impeding properties inside a battery; however, their direct addition to the electrolyte tends to cause adverse effects on the ionic conductivity and electrochemical performance of the cells. This study investigated an alternative option - the option to microencapsulate such additives into a neutral compound to ensure that the flame retardant has minimal/no effect on the performance of the battery. This investigation looked at tris(2-butoxyethyl) phosphate (TBP) and bis(2,2,2-trifluoroethyl) methylphosphonate (BFP) as flame retardant additives for the electrolyte. The TBP and BFP flame retardants were microencapsulated in poly(urea formaldehyde) (PUF) coating material via in situ polymerization method. The capsules were characterized using various analytical techniques - to prove it was successfully encapsulated. Electrochemical studies were further done on the capsules and neat flame retardants inside a coin cell. Self-extinguishing time (SET), which is the flammability test, proved that the additives have flame retarding abilities. Opto-digital microscopy (DSX) and scanning electron microscopy (SEM) did confirm the spherical shape of the microcapsules, where SEM also showed the smooth outer layer of the microcapsules and its hollow inner side. Fourier transform infrared spectroscopy (FTIR) proved the presence of the TBP and BFP inside the PUF resin by showing that the chemical composition of microcapsules consisted of both the PUF and flame retardant additives. Simultaneous DSC-TGA (DST) was also performed which showed that the microcapsules were stable before 200 °C, which indicates it would not decompose before the thermal runaway events are occurring. TGA analysis did show that the microcapsules underwent multiple decomposition steps upon heating. Additionally, 31P nuclear magnetic resonance (NMR) was used to quantify the amount of flame retardants additives encapsulated inside PUF shell, and also confirmed the stability of the microcapsules for one month in the electrolyte and at temperatures up to 200 °C. The ionic conductivity was vastly decreased when the flame retardants were added directly to the electrolyte. However, adding the flame retardants in a form of capsules had minimal effect on the ionic conductivity. The cycle capacities of the capsules were also improved when the capsules were added to the cell compared to that of neat flame retardants. The same effect was also noticed when doing Electrochemical Impedance Spectroscopy (EIS). This shows that microencapsulation improves the resistance of the cell caused by the flame retardant in comparison to when added directly to the electrolyte of the cell. , Thesis (MSC) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2022
- Full Text:
- Date Issued: 2022-04
Exploring the nature and scope of food insecurity among postgraduate students: a case of Nelson Mandela University
- Authors: Kuguyo, Yeukai T
- 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/10948/55348 , vital:51916
- Description: This study explores the nature and scope of food insecurity among postgraduate students at Nelson Mandela University, South Africa. The study employed a mixed method approach to access postgraduate students and university officials to investigate the prevalence of food insecurity. The approach also assesses the demographic factors; academic and mental implications along with the coping mechanisms associated with the experiences of food insecurity in higher education South Africa. The study incorporates an adapted conceptual framework from Alaimo’s food insecurity socio-economic risk models (2005) to understand the higher education context. Alaimo’s model seeks to connect the household conditions and broader systematic socio-economic mechanisms that households adopt to secure food. This model was adapted and employed in understanding the data collected while using a mixed-method approach between June and August 2021. The study employed an online survey for only postgraduate students enrolled at Nelson Mandela University (NMU) during the time of the study. This was supplemented by semi-structured interviews with student affairs officials that are directly involved in the formulation of strategies used to alleviate food insecurity at NMU. With 78 postgraduate students responding to the online survey, the study seems to confirm some of the studies done in this field on the inadequacy of food banks and food gardens in addressing food challenges effectively on campus. Similarly, the study found that the experiences of food insecurity were prevalent amongst postgraduate students that identified as black, low-income, and making access of the campus clinic for food relief. The study concluded by recommending a collaborative and a multi-level systematic approach in alleviating food insecurity in higher education. , Thesis (MA) -- Faculty of Humanities, School of Governmental and Social Sciences, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Kuguyo, Yeukai T
- 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/10948/55348 , vital:51916
- Description: This study explores the nature and scope of food insecurity among postgraduate students at Nelson Mandela University, South Africa. The study employed a mixed method approach to access postgraduate students and university officials to investigate the prevalence of food insecurity. The approach also assesses the demographic factors; academic and mental implications along with the coping mechanisms associated with the experiences of food insecurity in higher education South Africa. The study incorporates an adapted conceptual framework from Alaimo’s food insecurity socio-economic risk models (2005) to understand the higher education context. Alaimo’s model seeks to connect the household conditions and broader systematic socio-economic mechanisms that households adopt to secure food. This model was adapted and employed in understanding the data collected while using a mixed-method approach between June and August 2021. The study employed an online survey for only postgraduate students enrolled at Nelson Mandela University (NMU) during the time of the study. This was supplemented by semi-structured interviews with student affairs officials that are directly involved in the formulation of strategies used to alleviate food insecurity at NMU. With 78 postgraduate students responding to the online survey, the study seems to confirm some of the studies done in this field on the inadequacy of food banks and food gardens in addressing food challenges effectively on campus. Similarly, the study found that the experiences of food insecurity were prevalent amongst postgraduate students that identified as black, low-income, and making access of the campus clinic for food relief. The study concluded by recommending a collaborative and a multi-level systematic approach in alleviating food insecurity in higher education. , Thesis (MA) -- Faculty of Humanities, School of Governmental and Social Sciences, 2022
- Full Text:
- Date Issued: 2022-04
Hydraulic vulnerability of Subtropical Thicket to drought : a remote sensing and physiological perspective
- Authors: Buttner, Daniel Harry
- 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/10948/55455 , vital:52017
- Description: Water availability is one of largest constraints on plant survival, growth, and species distribution globally. The recent escalation in tree mortality coupled with declining precipitation and amplified temperatures has implicated drought as a major cause behind many large-scale dieback events observed across the world. Raising the question, what makes some species more resistant and persist while others dwindle and vanish from the landscape? The observed variability in species drought susceptibility demonstrates the complexity of physiological responses of plants to changes in water availability. Hydraulic dysfunction in plants has been purported to be the key mechanism behind drought-induced mortality provoking interest in hydraulic traits and critical thresholds of xylem physiological function. The capability of species to maintain hydraulic functionality under drought strongly influences the survival and general productivity towards water deficits. Hence, two core objectives, and subsequently aims, of this thesis are firstly to investigate the effect of drought on Subtropical Thicket vegetation health and productivity, and secondly to examine the underpinning physiological mechanisms and functional thresholds relaying speciesspecific drought vulnerability within this semi-arid biome. In first data chapter, this thesis offers an assessment of vegetation change under drought and its influence on plant physiological function and productivity across a subsection of Subtropical Thicket distribution. Additionally, this chapter provides a regional scale perspective of drought on Subtropical Thicket flora in the Eastern Cape of South Africa. A severe anomalous dieback event, which coincided with extreme, accumulative drought conditions was observed in 2020. Employing a combination of field-based approaches and remote sensing, this chapter aimed to provide a comprehensive report of the extent and severity of crown defoliation and canopy dieback following this event, additionally describing predisposing and compounding factors. Based on Standardized Precipitation Evapotranspiration and Standardized Precipitation Indices this event began in 2015 and coincided with amplified temperatures, exacerbating evaporative demand. Aerial UAV surveys and field-based investigations were undertaken. Remotely sensed (RS) indices provided an avenue for extensive spatiotemporal investigations to uncover the extent of drought-related impact on vegetation productivity and discuss potential underpinning mechanisms behind drought-induced mortality in Subtropical Thicket. Leveraging long-term time series RS data, Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI), from Moderate Resolution Imaging Spectroradiometer (MODIS) satellites as a proxy vegetation physiological status in combination with SPI and SPEI describing drought condition and groundbased surveying defining canopy vitality condition this study incidentally addressed the aim of endeavoring to link drought-induced mortality and early warning symptoms observed in the field with RS time series data to describe drought impacts across Subtropical Thicket. Furthermore, the findings of this chapter demonstrate the spatial and temporal heterogeneity in drought impacts on Subtropical Thicket. The recent drought of 2015 till 2021 is the longest documented period for the past 50 years in which there has been no accumulated net positive water availability, this apparently perpetual state of water deficiency has enacted a high cost for vegetation productivity and growth for the study area, exhibited well by average NDVI values of less than -0.5 for over 70% of the research site. The findings of this chapter report, to the contrary of anecdotal suggestions in the literature, on the intrinsic tolerance of Subtropical Thicket and that ii drought has a far more significant role on overall vegetation productivity, growth, and mortality in this region. The second data chapter assess whole-plant physiological functionality during a drought event in the Eastern Cape, South Africa. This is the first study in Subtropical Thicket to quantify in situ hydraulic functional integrity under a natural drought event testing the leading hypothesis describing tree mortality – hydraulic dysfunction. This chapter firstly, investigates hydraulic traits (e.g., turgor loss point) and describe key physiological thresholds (e.g., P50) for maintaining function during drought. Secondly, levels of native embolism were determined under drought conditions and combined with measurements of xylem vulnerability to embolism providing an estimation of degree of hydraulic dysfunction experienced by six dominant woody canopy species in Subtropical Thicket – to quantify interspecific drought tolerance and susceptibility. Subtropical Thicket species exhibited remarkable tolerance towards desiccation (TLP from as low as -3MPa) and hydraulic functional resistance to embolism (P50 value as low as -7.89MPa). The observed unexpected drought resilience of subtropical derived lineages highlights the intrinsic evolutionary role aridification had, selecting for greater embolism resistance and community-level conservatism in drought resistance of Subtropical Thicket. The level of native embolism and hydraulic safety margins identified two species (Schotia latifolia and Polyagla myrtifolia) that were the most vulnerable, and a third (Pappea capensis) moderately vulnerable, then the remaining studied species – this could result in community-level adjustments in species composition and structure under future projected climate change scenarios where, increased frequencies of drought events are anticipated. This retrospective assessment of canopy vigor with physiological functional thresholds evokes hydraulic dysfunction as the principal mechanism of observed Subtropical Thicket dieback to drought. This chapter provides crucial in situ data for predictive assertions around drought-induced mortality risk in a phylogenetically diverse and climatically unique biome of southern Africa; and is the first to identify critical hydraulic thresholds for tree species within this region. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Buttner, Daniel Harry
- 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/10948/55455 , vital:52017
- Description: Water availability is one of largest constraints on plant survival, growth, and species distribution globally. The recent escalation in tree mortality coupled with declining precipitation and amplified temperatures has implicated drought as a major cause behind many large-scale dieback events observed across the world. Raising the question, what makes some species more resistant and persist while others dwindle and vanish from the landscape? The observed variability in species drought susceptibility demonstrates the complexity of physiological responses of plants to changes in water availability. Hydraulic dysfunction in plants has been purported to be the key mechanism behind drought-induced mortality provoking interest in hydraulic traits and critical thresholds of xylem physiological function. The capability of species to maintain hydraulic functionality under drought strongly influences the survival and general productivity towards water deficits. Hence, two core objectives, and subsequently aims, of this thesis are firstly to investigate the effect of drought on Subtropical Thicket vegetation health and productivity, and secondly to examine the underpinning physiological mechanisms and functional thresholds relaying speciesspecific drought vulnerability within this semi-arid biome. In first data chapter, this thesis offers an assessment of vegetation change under drought and its influence on plant physiological function and productivity across a subsection of Subtropical Thicket distribution. Additionally, this chapter provides a regional scale perspective of drought on Subtropical Thicket flora in the Eastern Cape of South Africa. A severe anomalous dieback event, which coincided with extreme, accumulative drought conditions was observed in 2020. Employing a combination of field-based approaches and remote sensing, this chapter aimed to provide a comprehensive report of the extent and severity of crown defoliation and canopy dieback following this event, additionally describing predisposing and compounding factors. Based on Standardized Precipitation Evapotranspiration and Standardized Precipitation Indices this event began in 2015 and coincided with amplified temperatures, exacerbating evaporative demand. Aerial UAV surveys and field-based investigations were undertaken. Remotely sensed (RS) indices provided an avenue for extensive spatiotemporal investigations to uncover the extent of drought-related impact on vegetation productivity and discuss potential underpinning mechanisms behind drought-induced mortality in Subtropical Thicket. Leveraging long-term time series RS data, Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI), from Moderate Resolution Imaging Spectroradiometer (MODIS) satellites as a proxy vegetation physiological status in combination with SPI and SPEI describing drought condition and groundbased surveying defining canopy vitality condition this study incidentally addressed the aim of endeavoring to link drought-induced mortality and early warning symptoms observed in the field with RS time series data to describe drought impacts across Subtropical Thicket. Furthermore, the findings of this chapter demonstrate the spatial and temporal heterogeneity in drought impacts on Subtropical Thicket. The recent drought of 2015 till 2021 is the longest documented period for the past 50 years in which there has been no accumulated net positive water availability, this apparently perpetual state of water deficiency has enacted a high cost for vegetation productivity and growth for the study area, exhibited well by average NDVI values of less than -0.5 for over 70% of the research site. The findings of this chapter report, to the contrary of anecdotal suggestions in the literature, on the intrinsic tolerance of Subtropical Thicket and that ii drought has a far more significant role on overall vegetation productivity, growth, and mortality in this region. The second data chapter assess whole-plant physiological functionality during a drought event in the Eastern Cape, South Africa. This is the first study in Subtropical Thicket to quantify in situ hydraulic functional integrity under a natural drought event testing the leading hypothesis describing tree mortality – hydraulic dysfunction. This chapter firstly, investigates hydraulic traits (e.g., turgor loss point) and describe key physiological thresholds (e.g., P50) for maintaining function during drought. Secondly, levels of native embolism were determined under drought conditions and combined with measurements of xylem vulnerability to embolism providing an estimation of degree of hydraulic dysfunction experienced by six dominant woody canopy species in Subtropical Thicket – to quantify interspecific drought tolerance and susceptibility. Subtropical Thicket species exhibited remarkable tolerance towards desiccation (TLP from as low as -3MPa) and hydraulic functional resistance to embolism (P50 value as low as -7.89MPa). The observed unexpected drought resilience of subtropical derived lineages highlights the intrinsic evolutionary role aridification had, selecting for greater embolism resistance and community-level conservatism in drought resistance of Subtropical Thicket. The level of native embolism and hydraulic safety margins identified two species (Schotia latifolia and Polyagla myrtifolia) that were the most vulnerable, and a third (Pappea capensis) moderately vulnerable, then the remaining studied species – this could result in community-level adjustments in species composition and structure under future projected climate change scenarios where, increased frequencies of drought events are anticipated. This retrospective assessment of canopy vigor with physiological functional thresholds evokes hydraulic dysfunction as the principal mechanism of observed Subtropical Thicket dieback to drought. This chapter provides crucial in situ data for predictive assertions around drought-induced mortality risk in a phylogenetically diverse and climatically unique biome of southern Africa; and is the first to identify critical hydraulic thresholds for tree species within this region. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-04
Ifuthe leelwimi kwimpumelelo yabafundi bebanga leshumi elinambini kwizifundo zejiyografi(sezelizwe) kwizikolo ezibini ezichongiweyo kwisithili saseMonti
- Authors: Gcaki, Nomnqakati
- 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/10948/55342 , vital:51915
- Description: Isahluko sokuqala sixoxa ngengxaki yophando esi siseko kolu phando, nemibuzo yophando kunye neenjongo zokuba isifundo esikhoyo sifuna ukufezekisa ntoni. Ngokunxulumene nengxaki ephandwayo, esi sahluko sigxile kuphononongo loncwadi ukuze kuhlolwe ubudlelwane phakathi kolwimi lokufundisa kunye nempumelelo yabafundi kwiBanga le-12 kwisifundo seJiyografi. Ukuhlolwa koncwadi kuthathwe kwimigaqo-nkqubo yokufundisa kunye neethiyori zophuhliso lokuqonda nenkcubeko. Inkqubo yeethiyori ezikhethiweyo zisetyenziselwa ukwenza ingqiqo yokuba ulwimi lokufundisa luba nefuthe njani ekufundiseni nasekukhuleni kwengqondo nokuqiqa komfundi. Ngophononongo loncwadi, umphandi unqwenela ukufumanisa ubunzima abahlangabezana nabo abafundi ekufundeni iJiyografi ngolwimi lwesiNgesi kwiBanga leshumi elinesibini. Olu phando luza kuphonononga nzulu ifuthe leelwimi kwimpumelelo yabafundi kwisifundo seJiyografi kubafundi besigaba seshumi elinambini kujoliswe kwindlela abaphumelela ngayo kwiimviwo zokuphela konyaka.Olu phando luza kujongwa kwizikolo ezibini kwiphondo leMpuma Koloni kwisithili saseMonti phakathi kweminyaka wama-2016 ukuya kuma-2018.Ngokophando esele lwenziwe, abafundi abalwimi lwabo lwasekhaya lusisiXhosa kufanele ukuba bafundiswa ngolwimi lwabo abazikhethele lona ukutsho oko isiXhosa kwaye bavavanywe kwangalo. Oku akunjalo njengoko amaphepha abo ovavanyo engolwimi lwesiNgesi, lwimi olo olufika lubabeke phantsi konxinzelelo olukhulu olubenza bangabinakho ukuzithemba nokuziva bekhululekile xa bephendula imibuzo emagumbini okufundela. Umphandi olu luvo uluseka ngengxelo ayifumene kumaxwebhu eSebe lezeMfundo (2018 NSC Chief Markers Report) yesifundo seJiyografi iphepha lokuqala. , Thesis (MA) -- Faculty of Humanities, School of Language, Media and Communication, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Gcaki, Nomnqakati
- 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/10948/55342 , vital:51915
- Description: Isahluko sokuqala sixoxa ngengxaki yophando esi siseko kolu phando, nemibuzo yophando kunye neenjongo zokuba isifundo esikhoyo sifuna ukufezekisa ntoni. Ngokunxulumene nengxaki ephandwayo, esi sahluko sigxile kuphononongo loncwadi ukuze kuhlolwe ubudlelwane phakathi kolwimi lokufundisa kunye nempumelelo yabafundi kwiBanga le-12 kwisifundo seJiyografi. Ukuhlolwa koncwadi kuthathwe kwimigaqo-nkqubo yokufundisa kunye neethiyori zophuhliso lokuqonda nenkcubeko. Inkqubo yeethiyori ezikhethiweyo zisetyenziselwa ukwenza ingqiqo yokuba ulwimi lokufundisa luba nefuthe njani ekufundiseni nasekukhuleni kwengqondo nokuqiqa komfundi. Ngophononongo loncwadi, umphandi unqwenela ukufumanisa ubunzima abahlangabezana nabo abafundi ekufundeni iJiyografi ngolwimi lwesiNgesi kwiBanga leshumi elinesibini. Olu phando luza kuphonononga nzulu ifuthe leelwimi kwimpumelelo yabafundi kwisifundo seJiyografi kubafundi besigaba seshumi elinambini kujoliswe kwindlela abaphumelela ngayo kwiimviwo zokuphela konyaka.Olu phando luza kujongwa kwizikolo ezibini kwiphondo leMpuma Koloni kwisithili saseMonti phakathi kweminyaka wama-2016 ukuya kuma-2018.Ngokophando esele lwenziwe, abafundi abalwimi lwabo lwasekhaya lusisiXhosa kufanele ukuba bafundiswa ngolwimi lwabo abazikhethele lona ukutsho oko isiXhosa kwaye bavavanywe kwangalo. Oku akunjalo njengoko amaphepha abo ovavanyo engolwimi lwesiNgesi, lwimi olo olufika lubabeke phantsi konxinzelelo olukhulu olubenza bangabinakho ukuzithemba nokuziva bekhululekile xa bephendula imibuzo emagumbini okufundela. Umphandi olu luvo uluseka ngengxelo ayifumene kumaxwebhu eSebe lezeMfundo (2018 NSC Chief Markers Report) yesifundo seJiyografi iphepha lokuqala. , Thesis (MA) -- Faculty of Humanities, School of Language, Media and Communication, 2022
- Full Text:
- Date Issued: 2022-04
Potential suppressive effects of alien Acacia melanoxylon on Afrotemperate Forest tree recruitment
- Miles, Bayleigh, Baard, Johan
- Authors: Miles, Bayleigh , Baard, Johan
- 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/10948/55391 , vital:51989
- Description: Acacia melanoxylon R.Br. is a prominent alien and invasive species in many parts of the world and evidence exists of its adverse effects on indigenous forest community composition through allelopathy and alteration of light regimes. The species also occurs extensively in Southern Cape Afrotemperate Forest (South Africa) and is thought to suppress indigenous Afrotemperate Forest tree seedlings through various mechanisms such as the alteration of natural light regimes or allelopathy, although this has not been rigorously verified. This study aimed to investigate whether Acacia melanoxylon has a suppressive effect on Afrotemperate Forest tree recruitment. Firstly, we assessed the potential allelopathic effect of Acacia melanoxylon and an indigenous Afrotemperate Forest species Olea capensis macrocarpa (C.H.Wright) I.Verd. on the germination of Acacia melanoxylon and three prominent indigenous tree species’ seedlings in a nursery trial. Germination of the indigenous species failed; however, we were able to compare the germination of Acacia melanoxylon among the three treatments, namely Acacia melanoxylon leachate, Olea capensis leachate, and no leachate. The average germination of Acacia melanoxylon was 67% and germination was marginally higher under Acacia melanoxylon leachate and Olea capensis leachate, respectively, than under the control. This suggested that germination of the species is improved, or at the least, unaffected, by leachates of itself or that of a common indigenous canopy species. We then critically evaluated the germination requirements of the indigenous test species to determine probable reasons why their germination failed in our trial. The most plausible explanation for the germination failure could be that the trial period did not encompass an entire winter season and may not have provided adequate cold stratification. We concluded that the lack of sensitivity of Acacia melanoxylon to leachates of itself or a common indigenous overstorey species likely contribute to its success as an invasive species in Southern Cape Afrotemperate Forest. Secondly, we investigated, through field surveys, whether Acacia melanoxylon affects indigenous Afrotemperate Forest tree sapling composition and light regimes underneath its canopy. Using a paired plot design, we compared light intensity, tree sapling species richness, diversity, and density underneath 30 overstorey Acacia melanoxylon trees and 30 indigenous counterparts. We recorded 2506 indigenous tree saplings from 29 species in the 60 plots and found that there were no significant differences in richness, diversity, or v density of saplings underneath Acacia melanoxylon compared to that under indigenous counterparts. Light intensity did not differ significantly underneath Acacia melanoxylon and indigenous canopies, however light intensity varied significantly more underneath the canopies of Acacia melanoxylon. Canonical correspondence analysis of the abundance of sapling species confirmed that sapling composition was not largely determined by the overstorey species. We concluded that Acacia melanoxylon does not significantly alter indigenous tree species composition underneath its canopy at the typical densities (<3 trees per hectare) at which it occurred in the forests of the Garden Route National Park that we surveyed. Nevertheless, populations of Acacia melanoxylon in the forest interior still act as a source of propagules for invasion in forest margins, riparian areas, and neighbouring fynbos shrubland. These invasive attributes need to be considered in the management of the species in the region at large. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Miles, Bayleigh , Baard, Johan
- 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/10948/55391 , vital:51989
- Description: Acacia melanoxylon R.Br. is a prominent alien and invasive species in many parts of the world and evidence exists of its adverse effects on indigenous forest community composition through allelopathy and alteration of light regimes. The species also occurs extensively in Southern Cape Afrotemperate Forest (South Africa) and is thought to suppress indigenous Afrotemperate Forest tree seedlings through various mechanisms such as the alteration of natural light regimes or allelopathy, although this has not been rigorously verified. This study aimed to investigate whether Acacia melanoxylon has a suppressive effect on Afrotemperate Forest tree recruitment. Firstly, we assessed the potential allelopathic effect of Acacia melanoxylon and an indigenous Afrotemperate Forest species Olea capensis macrocarpa (C.H.Wright) I.Verd. on the germination of Acacia melanoxylon and three prominent indigenous tree species’ seedlings in a nursery trial. Germination of the indigenous species failed; however, we were able to compare the germination of Acacia melanoxylon among the three treatments, namely Acacia melanoxylon leachate, Olea capensis leachate, and no leachate. The average germination of Acacia melanoxylon was 67% and germination was marginally higher under Acacia melanoxylon leachate and Olea capensis leachate, respectively, than under the control. This suggested that germination of the species is improved, or at the least, unaffected, by leachates of itself or that of a common indigenous canopy species. We then critically evaluated the germination requirements of the indigenous test species to determine probable reasons why their germination failed in our trial. The most plausible explanation for the germination failure could be that the trial period did not encompass an entire winter season and may not have provided adequate cold stratification. We concluded that the lack of sensitivity of Acacia melanoxylon to leachates of itself or a common indigenous overstorey species likely contribute to its success as an invasive species in Southern Cape Afrotemperate Forest. Secondly, we investigated, through field surveys, whether Acacia melanoxylon affects indigenous Afrotemperate Forest tree sapling composition and light regimes underneath its canopy. Using a paired plot design, we compared light intensity, tree sapling species richness, diversity, and density underneath 30 overstorey Acacia melanoxylon trees and 30 indigenous counterparts. We recorded 2506 indigenous tree saplings from 29 species in the 60 plots and found that there were no significant differences in richness, diversity, or v density of saplings underneath Acacia melanoxylon compared to that under indigenous counterparts. Light intensity did not differ significantly underneath Acacia melanoxylon and indigenous canopies, however light intensity varied significantly more underneath the canopies of Acacia melanoxylon. Canonical correspondence analysis of the abundance of sapling species confirmed that sapling composition was not largely determined by the overstorey species. We concluded that Acacia melanoxylon does not significantly alter indigenous tree species composition underneath its canopy at the typical densities (<3 trees per hectare) at which it occurred in the forests of the Garden Route National Park that we surveyed. Nevertheless, populations of Acacia melanoxylon in the forest interior still act as a source of propagules for invasion in forest margins, riparian areas, and neighbouring fynbos shrubland. These invasive attributes need to be considered in the management of the species in the region at large. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2022
- Full Text:
- Date Issued: 2022-04
Spatial modelling of accessibility to tuberculosis treatment: the case of Ngaka Modiri Molema District
- Authors: Ramotsongwa, Karabo Naome
- 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/10948/55435 , vital:52000
- Description: Accessibility to healthcare refers to the availability, or the provision of healthcare-byhealthcare professionals and stakeholders and individuals' ability to obtain care and treatment. It affects overall physical, social, and mental health; disease and disability prevention; detection and treatment of health conditions; standard of living; preventable death; and life expectancy, and it is crucial to the performance of health care systems around the world. If healthcare services are available and are in sufficient supply, people will be able to seek health care, and a population will have access to services. The leading cause of death globally is Tuberculosis (TB) and South Africa is amongst the top 5 countries most affected by TB. This is aggravated by high HIV/AIDS statistics. Children belowthe age of 4, between the ages of 4- 15, and women and men of working ages are highly affected by TB and it is the primary cause of death in these groups in the Ngaka Modiri Molema District. This study used study tools like Spatial Modelling, Geographic Information Systems and software like ArcGIS 10.5, TerrSet IDRISI 18.30, and secondary data from the North West Departmentof Health (Tier.net &DHIS) and also TB patients’ home addresses to investigate the accessibility of TB treatment in Ngaka Modiri Molema, in order to spatially visualize the distribution of a communicable disease like TB and public healthcare facilities in the Ngaka Modiri Molema (NMM) District and suggest optimum sites for hospital facilities. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Ramotsongwa, Karabo Naome
- 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/10948/55435 , vital:52000
- Description: Accessibility to healthcare refers to the availability, or the provision of healthcare-byhealthcare professionals and stakeholders and individuals' ability to obtain care and treatment. It affects overall physical, social, and mental health; disease and disability prevention; detection and treatment of health conditions; standard of living; preventable death; and life expectancy, and it is crucial to the performance of health care systems around the world. If healthcare services are available and are in sufficient supply, people will be able to seek health care, and a population will have access to services. The leading cause of death globally is Tuberculosis (TB) and South Africa is amongst the top 5 countries most affected by TB. This is aggravated by high HIV/AIDS statistics. Children belowthe age of 4, between the ages of 4- 15, and women and men of working ages are highly affected by TB and it is the primary cause of death in these groups in the Ngaka Modiri Molema District. This study used study tools like Spatial Modelling, Geographic Information Systems and software like ArcGIS 10.5, TerrSet IDRISI 18.30, and secondary data from the North West Departmentof Health (Tier.net &DHIS) and also TB patients’ home addresses to investigate the accessibility of TB treatment in Ngaka Modiri Molema, in order to spatially visualize the distribution of a communicable disease like TB and public healthcare facilities in the Ngaka Modiri Molema (NMM) District and suggest optimum sites for hospital facilities. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-04
The application of the prescription act in labour disputes
- Authors: Mncanca, Siyamthanda
- 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/10948/55498 , vital:52375
- Description: It is inevitable that in an employment relationship grievances and conflicts may emerge.1 This is attested to by the large volume of 193 732 disputes that were referred to the Commission for Conciliation, Mediation and Arbitration (CCMA) during the 2018/19 financial year.2 In the event where an employee is dismissed from work and he decides to challenge the dismissal, section 191 of the Labour Relations Act (LRA) grants the employee a right to refer the matter to the CCMA for conciliation or arbitration.3 The purpose of referring the disputes to the CCMA is to support an establishment of a voluntary, free of charge and expeditious mechanisms for labour disputes settlement and allow parties to resolve their disputes through a consensus based process before taking the route of a court process.4 There are time frames that are provided for the referral of disputes to the CCMA. Section 191 determines these time frames by stating that an employee must refer their alleged unfair dismissal to the CCMA within 30 days or 90 days when a dispute relates to an unfair labour practice in accordance with section 191(1)(b)(ii) of the LRA.5 The rationale behind these time frames was outlined in the Constitutional Court (CC) judgement of Toyota SA Motors (Pty) Ltd v CCMA,6 as a means to bring about the expeditious resolution of labour disputes which by their nature, require speedy resolution. , Thesis (L.L.M.) -- Faculty of Law, Mercantile Law, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Mncanca, Siyamthanda
- 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/10948/55498 , vital:52375
- Description: It is inevitable that in an employment relationship grievances and conflicts may emerge.1 This is attested to by the large volume of 193 732 disputes that were referred to the Commission for Conciliation, Mediation and Arbitration (CCMA) during the 2018/19 financial year.2 In the event where an employee is dismissed from work and he decides to challenge the dismissal, section 191 of the Labour Relations Act (LRA) grants the employee a right to refer the matter to the CCMA for conciliation or arbitration.3 The purpose of referring the disputes to the CCMA is to support an establishment of a voluntary, free of charge and expeditious mechanisms for labour disputes settlement and allow parties to resolve their disputes through a consensus based process before taking the route of a court process.4 There are time frames that are provided for the referral of disputes to the CCMA. Section 191 determines these time frames by stating that an employee must refer their alleged unfair dismissal to the CCMA within 30 days or 90 days when a dispute relates to an unfair labour practice in accordance with section 191(1)(b)(ii) of the LRA.5 The rationale behind these time frames was outlined in the Constitutional Court (CC) judgement of Toyota SA Motors (Pty) Ltd v CCMA,6 as a means to bring about the expeditious resolution of labour disputes which by their nature, require speedy resolution. , Thesis (L.L.M.) -- Faculty of Law, Mercantile Law, 2022
- Full Text:
- Date Issued: 2022-04
The use of psychometric test systems as a pre-selection tool for identifying successful harvesting machine operators
- Authors: Schwegman, Kylle
- Date: 2022-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/55246 , vital:51102
- Description: A shift towards fully mechanized forest activities, such as harvesting and, more recently, silviculture, has occurred from the early 2 000’s. The reason for mechanizing these activities differs for each country, although for most countries there is concern relating to the health and safety of forest workers. With mechanization in harvesting, the forest worker has moved away from the physical intensity of having to fell, debranch, debark and cross-cut trees into logs using either an axe or chainsaw, to operating a machine. Studies revolving around the human element (operator) have been conducted specifically relating to the ergonomics of the machines and how operators may influence machine productivity. Results showed that due to the repetitive nature of the work, the operators are exposed to associated stresses for longer periods. Typical injuries associated to these kinds of stressors are whole body vibrations (WBVs), repetitive hand and arm movements, non-neutral body postures and manual lifting, which lead to musculoskeletal symptoms in the lower back, neck and shoulders. However, as machine technology improves so does the ergonomic conditions which are experienced by machine operators. Machine productivity can be influenced by various factors, with the most influential being tree volume. However, a recent study showed that over 40% of variation in machine productivity has been observed amongst different machine operators operating similar machines. The specific reason for these differences has yet to be determined. However, decision making, motivation, planning capacity, concentration, memory, motor coordination, pattern recognition, logic reasoning, and spatial perception are abilities that have been described as important for successful harvesting work. The pre-selection of operators using psychometric and cognitive tests is not new to forestry, although very little information is available relating to the aptitude test known as the Vienna test system as well as the best possible demographic associated with successful harvesting operators. The overall aim of this study was to determine whether the high variation found amongst harvesting machine operators could be reduced initially through a preselection process which involves the use of aptitude tests (Vienna Test System) and demographic questionnaires. A study was implemented in Zululand, South Africa, testing whether there were significant productivity differences between nine machine operators. , Thesis (PhD) -- Faculty of Science, School of Natural Resource Management, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Schwegman, Kylle
- Date: 2022-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/55246 , vital:51102
- Description: A shift towards fully mechanized forest activities, such as harvesting and, more recently, silviculture, has occurred from the early 2 000’s. The reason for mechanizing these activities differs for each country, although for most countries there is concern relating to the health and safety of forest workers. With mechanization in harvesting, the forest worker has moved away from the physical intensity of having to fell, debranch, debark and cross-cut trees into logs using either an axe or chainsaw, to operating a machine. Studies revolving around the human element (operator) have been conducted specifically relating to the ergonomics of the machines and how operators may influence machine productivity. Results showed that due to the repetitive nature of the work, the operators are exposed to associated stresses for longer periods. Typical injuries associated to these kinds of stressors are whole body vibrations (WBVs), repetitive hand and arm movements, non-neutral body postures and manual lifting, which lead to musculoskeletal symptoms in the lower back, neck and shoulders. However, as machine technology improves so does the ergonomic conditions which are experienced by machine operators. Machine productivity can be influenced by various factors, with the most influential being tree volume. However, a recent study showed that over 40% of variation in machine productivity has been observed amongst different machine operators operating similar machines. The specific reason for these differences has yet to be determined. However, decision making, motivation, planning capacity, concentration, memory, motor coordination, pattern recognition, logic reasoning, and spatial perception are abilities that have been described as important for successful harvesting work. The pre-selection of operators using psychometric and cognitive tests is not new to forestry, although very little information is available relating to the aptitude test known as the Vienna test system as well as the best possible demographic associated with successful harvesting operators. The overall aim of this study was to determine whether the high variation found amongst harvesting machine operators could be reduced initially through a preselection process which involves the use of aptitude tests (Vienna Test System) and demographic questionnaires. A study was implemented in Zululand, South Africa, testing whether there were significant productivity differences between nine machine operators. , Thesis (PhD) -- Faculty of Science, School of Natural Resource Management, 2022
- Full Text:
- Date Issued: 2022-04
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