Optical surface quality and molecular dynamics modelling of ultra-high precision optical silicon machining
- Authors: Abdulkadir, Lukman Niyi
- Date: 2019-04
- Subjects: Lasers -- Industrial applications , Manufacturing processes , Materials science
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/66551 , vital:75600
- Description: Hard and brittle materials, such as silicon, silicon carbide etc., are widely used in aerospace, integrated circuit, and other fields due to their excellent physical and chemical properties. However, these materials display poor machinability owing to hardness, brittleness, non-linearity in machining process and complexities in selecting suitable machining parameters and tool geometry. These leads to low quality lenses due to subsurface damage and surface micro-crack. Additionally, it is experimentally very difficult to observe all nanoscale physical phenomena due to in-process measurement problems, inaccessible contact area of tool and workpiece, and the difficulty of surface analysis. With the use of molecular dynamics (MD) which is a comprehensive nanoscale modelling technique, proper selection of process parameters, tool geometry and online monitoring techniques, production of freeform optics is possible through Ultra-high precision diamond turning (UHPDT). Though, depending on view point, machinability in UHPDT may be in terms of tool wear rate, hardness, chip morphology, surface roughness, and other benchmarks. These situations have called for more insights, which on the long run will help to achieve high precision manufacturing with predictability, repeatability, productivity and high infrared (IR) optical quality. In this thesis, UHPDT of monocrystalline silicon at atomistic scale was conducted to investigate combined effects of edge radius, feed rate, cutting speed, depth of cut, rake and clearance angles hitherto not done so far. Using appropriate potential functions with the MD algorithm, comprehensive analysis of thermal effects, diamond tool wear, phase change, cutting forces and machining stresses (normal, shear, hydrostatic and von Mises) were carried out. Dislocation extraction algorithm (DXA) and radial distribution function (RDF) were used to evaluate dislocation nucleation, variations in bond lengths, microstructural transformation and represents structural changes in histogram form. Selected parameters for optical quality surface roughness were afterwards compared and optimized through response surface methodology (RSM) based on Box Behnken (BBD) and Taguchi L9 methods. The results indicated that, silicon atoms in the chip formation zone undergo high pressure phase transformation (HPPT) at high hydrostatic pressure and temperature Silicon microstructure transformed from four-coordinated diamond cubic structure (Si-I) to unstable six-coordinated body-centered tetragonal structure (β-silicon) which then transformed to amorphous silicon atoms (a-Si) through amorphization. These resulted in plastic deformation and defects in the machining zone causing subsurface damage. Stress analysis indicated that the compressive stress in the machining zone (i.e.amorphous region) suppressed crack formation contributing to continuous plastic flow which is responsible for silicon ductile-mode cutting. Furthermore, formation of silicon carbide which constituted diamond wear was observed to be by sp3 - sp2 diamond carbon atom disorder and tribochemistry. The tribochemistry occurred through both multiphase and solid-state single-phase reaction between diamond tool and silicon workpiece at cutting temperatures above and below 959 K. Both the experimental findings and the simulation results reveal that, at edge radius less than uncut chip thickness, tool wear was more of rake wear than flank wear. Tool wear and kinetic friction reduced as the edge radius approached the uncut chip thickness while forces, stresses and SCE increased. When machining silicon at different ratio, silicon stress state, SCE, SSD, forces (reduced with increase in clearance angle), shear plane, chip velocity and chip ratio increased as edge radius and rake angle increased, while, kinetic friction, chip length and thickness reduced. The crystal lattice of the machined surfaces and subsurface deformed layer depth increased with increase in edge radius, feed and rake angle. Amongst all tested and analysed parameters, feed rate had the highest influence on surface quality while depth of cut showed the least. Acoustic emission was also monitored during machining and its results statistically analysed. The trends of the monitored acoustic emissions showed its capability to adequately represent and predict surface roughness results. Based on the developed simulation model a novel method for quantitative assessment of tool wear was proposed. The proposed model can be used to compare tool wear using graphitization and tribochemistry to decide the path and mode of the diamond tool wear. Finally, based on the experiment results and predictive model, a novel combination and hierarchical arrangement of the considered factors capable of suppressing tool wear and improve attainable machined surface roughness when turning hard-to-machine materials was proposed. , Thesis (PhD) -- Faculty of Engineering, the Built Environment, and Technology, School of Engineering, 2019
- Full Text:
- Date Issued: 2019-04
- Authors: Abdulkadir, Lukman Niyi
- Date: 2019-04
- Subjects: Lasers -- Industrial applications , Manufacturing processes , Materials science
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/66551 , vital:75600
- Description: Hard and brittle materials, such as silicon, silicon carbide etc., are widely used in aerospace, integrated circuit, and other fields due to their excellent physical and chemical properties. However, these materials display poor machinability owing to hardness, brittleness, non-linearity in machining process and complexities in selecting suitable machining parameters and tool geometry. These leads to low quality lenses due to subsurface damage and surface micro-crack. Additionally, it is experimentally very difficult to observe all nanoscale physical phenomena due to in-process measurement problems, inaccessible contact area of tool and workpiece, and the difficulty of surface analysis. With the use of molecular dynamics (MD) which is a comprehensive nanoscale modelling technique, proper selection of process parameters, tool geometry and online monitoring techniques, production of freeform optics is possible through Ultra-high precision diamond turning (UHPDT). Though, depending on view point, machinability in UHPDT may be in terms of tool wear rate, hardness, chip morphology, surface roughness, and other benchmarks. These situations have called for more insights, which on the long run will help to achieve high precision manufacturing with predictability, repeatability, productivity and high infrared (IR) optical quality. In this thesis, UHPDT of monocrystalline silicon at atomistic scale was conducted to investigate combined effects of edge radius, feed rate, cutting speed, depth of cut, rake and clearance angles hitherto not done so far. Using appropriate potential functions with the MD algorithm, comprehensive analysis of thermal effects, diamond tool wear, phase change, cutting forces and machining stresses (normal, shear, hydrostatic and von Mises) were carried out. Dislocation extraction algorithm (DXA) and radial distribution function (RDF) were used to evaluate dislocation nucleation, variations in bond lengths, microstructural transformation and represents structural changes in histogram form. Selected parameters for optical quality surface roughness were afterwards compared and optimized through response surface methodology (RSM) based on Box Behnken (BBD) and Taguchi L9 methods. The results indicated that, silicon atoms in the chip formation zone undergo high pressure phase transformation (HPPT) at high hydrostatic pressure and temperature Silicon microstructure transformed from four-coordinated diamond cubic structure (Si-I) to unstable six-coordinated body-centered tetragonal structure (β-silicon) which then transformed to amorphous silicon atoms (a-Si) through amorphization. These resulted in plastic deformation and defects in the machining zone causing subsurface damage. Stress analysis indicated that the compressive stress in the machining zone (i.e.amorphous region) suppressed crack formation contributing to continuous plastic flow which is responsible for silicon ductile-mode cutting. Furthermore, formation of silicon carbide which constituted diamond wear was observed to be by sp3 - sp2 diamond carbon atom disorder and tribochemistry. The tribochemistry occurred through both multiphase and solid-state single-phase reaction between diamond tool and silicon workpiece at cutting temperatures above and below 959 K. Both the experimental findings and the simulation results reveal that, at edge radius less than uncut chip thickness, tool wear was more of rake wear than flank wear. Tool wear and kinetic friction reduced as the edge radius approached the uncut chip thickness while forces, stresses and SCE increased. When machining silicon at different ratio, silicon stress state, SCE, SSD, forces (reduced with increase in clearance angle), shear plane, chip velocity and chip ratio increased as edge radius and rake angle increased, while, kinetic friction, chip length and thickness reduced. The crystal lattice of the machined surfaces and subsurface deformed layer depth increased with increase in edge radius, feed and rake angle. Amongst all tested and analysed parameters, feed rate had the highest influence on surface quality while depth of cut showed the least. Acoustic emission was also monitored during machining and its results statistically analysed. The trends of the monitored acoustic emissions showed its capability to adequately represent and predict surface roughness results. Based on the developed simulation model a novel method for quantitative assessment of tool wear was proposed. The proposed model can be used to compare tool wear using graphitization and tribochemistry to decide the path and mode of the diamond tool wear. Finally, based on the experiment results and predictive model, a novel combination and hierarchical arrangement of the considered factors capable of suppressing tool wear and improve attainable machined surface roughness when turning hard-to-machine materials was proposed. , Thesis (PhD) -- Faculty of Engineering, the Built Environment, and Technology, School of Engineering, 2019
- Full Text:
- Date Issued: 2019-04
Perceptions of social media as a tool for research: a study of postgraduate students, University of Fort Hare, Alice campus
- Authors: Abolanle, Ogunnubi Adeyemi
- Date: 2014-10
- Subjects: University of Fort Hare , Media literacy , Internet research
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/26381 , vital:65299
- Description: The study aimed at examining the perceptions of social media as a tool for research among postgraduate students at the University of Fort Hare, Alice campus. Data were collected using a quantitative research approach by administering structured questionnaires to 310 postgraduate students under the cluster sampling across different faculties and departments, and analysed by SPSS Statistical software and Chi-square test. 264 questionnaires were returned for analysis and these respondents maintained that they utilized social media platforms for their academic research. The findings further revealed that social media has to a large extent improved students‟ research activities as they frequently seek practical knowledge for demonstration and tutorship. Furthermore, the respondents regard social media as a good platform for research topics in audio and video formats, scholarly articles, journals and books. This study concluded that since students explore the social media platforms and search engines for various reasons, academic research inclusive, it therefore becomes imperative to create more links within the social media for students to explore books, scholarly journals and articles necessary for research and academic purposes. , Thesis (MSoc) -- Faculty of Social Sciences and Humanities, 2014
- Full Text:
- Date Issued: 2014-10
- Authors: Abolanle, Ogunnubi Adeyemi
- Date: 2014-10
- Subjects: University of Fort Hare , Media literacy , Internet research
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/26381 , vital:65299
- Description: The study aimed at examining the perceptions of social media as a tool for research among postgraduate students at the University of Fort Hare, Alice campus. Data were collected using a quantitative research approach by administering structured questionnaires to 310 postgraduate students under the cluster sampling across different faculties and departments, and analysed by SPSS Statistical software and Chi-square test. 264 questionnaires were returned for analysis and these respondents maintained that they utilized social media platforms for their academic research. The findings further revealed that social media has to a large extent improved students‟ research activities as they frequently seek practical knowledge for demonstration and tutorship. Furthermore, the respondents regard social media as a good platform for research topics in audio and video formats, scholarly articles, journals and books. This study concluded that since students explore the social media platforms and search engines for various reasons, academic research inclusive, it therefore becomes imperative to create more links within the social media for students to explore books, scholarly journals and articles necessary for research and academic purposes. , Thesis (MSoc) -- Faculty of Social Sciences and Humanities, 2014
- Full Text:
- Date Issued: 2014-10
Exploring targeted metagenomics and untargeted metabolomics for characterising aquaponics bacterial ecology and phytochemistry
- Authors: Abraham, Benjamin Melakail
- Date: 2021-10-29
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192453 , vital:45227
- Description: Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Abraham, Benjamin Melakail
- Date: 2021-10-29
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192453 , vital:45227
- Description: Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2021
- Full Text:
- Date Issued: 2021-10-29
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
Exploring the diverse racialised responses to the ‘Ashwin Willemse incident’ through theories of race and coloniality of being
- Authors: Accom, Abner
- Date: 2022-10-14
- Subjects: Willemse, Ashwin, 1981- , Ethnic attitudes South Africa , Race awareness South Africa , Postcolonialism South Africa , South Africa Race relations , Decolonization South Africa , Racism in sports South Africa
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/405908 , vital:70218
- Description: On 19 May 2018 Ashwin Willemse, a coloured Springbok rugby player walked off the SuperSport set, a DSTV sports program, during a live broadcast. He accused his white co-hosts Nick Mallet and Naas Botha (two white apartheid-era Springboks) of patronising him (SABC News, 2018; Eyewitness News, 2018). Responses to the Willemse incident reflected racial divisions in the country. It appeared that many white South Africans criticised Willemse’s behaviour, while many black South Africans stated that they could identify with his response to the subtle racisms experienced in everyday life, and which he claimed to have experienced on the SuperSport program (SABC News, 2018; Eyewitness News, 2018). The racialised media outcry led Professor Jonathan Jansen, to ask: “why do two groups of people, staring at the same event ‘see’ two different realities” (Maleka, 2018: 4)? This thesis probes possible answers to Jonathan Jansen’s question regarding the Ashwin Willemse walkout. The thesis explores and analyses the diverse racialised responses to the ‘Willemse walkout’ through race theories and ‘coloniality of being’. Qualitative research methods were used in the form of a reception analysis involving two racially homogenous (black and white) focus group interviews, two in-depth individual interviews with black research participants, three in-depth individual interviews with white research participants, and a sample of tweets from black and white commentators who had opinions about the ‘Willemse walkout’. The thesis concludes that most black research participants supported Willemse’s actions and most of the white people in the group disagreed with Willemse’s behaviour. Their various opinions were largely due to their different lived experiences which were a consequence of South Africa’s colonial history, apartheid, and racial discrimination. , Thesis (MA) -- Faculty of Humanities, School of Journalism and Media Studies, 2022
- Full Text:
- Date Issued: 2022-10-14
- Authors: Accom, Abner
- Date: 2022-10-14
- Subjects: Willemse, Ashwin, 1981- , Ethnic attitudes South Africa , Race awareness South Africa , Postcolonialism South Africa , South Africa Race relations , Decolonization South Africa , Racism in sports South Africa
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/405908 , vital:70218
- Description: On 19 May 2018 Ashwin Willemse, a coloured Springbok rugby player walked off the SuperSport set, a DSTV sports program, during a live broadcast. He accused his white co-hosts Nick Mallet and Naas Botha (two white apartheid-era Springboks) of patronising him (SABC News, 2018; Eyewitness News, 2018). Responses to the Willemse incident reflected racial divisions in the country. It appeared that many white South Africans criticised Willemse’s behaviour, while many black South Africans stated that they could identify with his response to the subtle racisms experienced in everyday life, and which he claimed to have experienced on the SuperSport program (SABC News, 2018; Eyewitness News, 2018). The racialised media outcry led Professor Jonathan Jansen, to ask: “why do two groups of people, staring at the same event ‘see’ two different realities” (Maleka, 2018: 4)? This thesis probes possible answers to Jonathan Jansen’s question regarding the Ashwin Willemse walkout. The thesis explores and analyses the diverse racialised responses to the ‘Willemse walkout’ through race theories and ‘coloniality of being’. Qualitative research methods were used in the form of a reception analysis involving two racially homogenous (black and white) focus group interviews, two in-depth individual interviews with black research participants, three in-depth individual interviews with white research participants, and a sample of tweets from black and white commentators who had opinions about the ‘Willemse walkout’. The thesis concludes that most black research participants supported Willemse’s actions and most of the white people in the group disagreed with Willemse’s behaviour. Their various opinions were largely due to their different lived experiences which were a consequence of South Africa’s colonial history, apartheid, and racial discrimination. , Thesis (MA) -- Faculty of Humanities, School of Journalism and Media Studies, 2022
- Full Text:
- Date Issued: 2022-10-14
The role of climate change on food security in Northern Uganda a case study of Lira district
- Authors: Aciro, Prudence Estel
- Date: 2022-04
- Subjects: Food security -- Uganda , Food security -- Climatic factors , Climatic changes
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/57513 , vital:58054
- Description: The study examines the effects of climate change in Northern Uganda to create food security solutions through the improvement of local resilience mechanisms and adaptation devices. The study adopted the interpretive paradigm within the qualitative research methodology as it investigated the subjective opinions of the respondents about the role of climate change on food security in the Lira district. The researcher used non-probability purposive sampling to identify nine officials that possessed knowledge on resilience mechanisms and also interacted directly with individual farmers. The researcher used semi-structured interviews as a tool to collect data and thematic analysis to make conclusions on findings based on the emerging themes. The findings from the study revealed that the four determinants of food security are greatly affected by climate events and these are: food utilisation, food production, food availability and access to food as well as the stability of food supply. Food storage is a problem facing the community of Lira due to extreme climate events. Climate change was found to affect food prices in such a way that when agricultural inputs are bought expensively, it leads the cost of producing crops to increase, which in turn makes food more expensive at the market. The findings also displayed that Lira’s local communities are trying to apply adaptive farming practices to ensure there is an adequate food supply, such as planting a local variety of seeds that withstand the effect of climate change, such as sorghum millet and cassava. Based on the findings, valuable recommendations are offered. These include the government rolling out a national irrigation scheme to ease the use of the drip irrigation mechanism. Also, there is a need for more interventions that support local resilience mechanisms such as the use of agricultural inputs, as these require subsidisation. It emerged from the findings of this study that there is a need for better interventions to deal with flooding. For future researchers, it was found that there is a need to explore the best post-harvest handling methods as well as food storage. , Thesis (MA) -- Faculty of Business and Economic Sciences, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Aciro, Prudence Estel
- Date: 2022-04
- Subjects: Food security -- Uganda , Food security -- Climatic factors , Climatic changes
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/57513 , vital:58054
- Description: The study examines the effects of climate change in Northern Uganda to create food security solutions through the improvement of local resilience mechanisms and adaptation devices. The study adopted the interpretive paradigm within the qualitative research methodology as it investigated the subjective opinions of the respondents about the role of climate change on food security in the Lira district. The researcher used non-probability purposive sampling to identify nine officials that possessed knowledge on resilience mechanisms and also interacted directly with individual farmers. The researcher used semi-structured interviews as a tool to collect data and thematic analysis to make conclusions on findings based on the emerging themes. The findings from the study revealed that the four determinants of food security are greatly affected by climate events and these are: food utilisation, food production, food availability and access to food as well as the stability of food supply. Food storage is a problem facing the community of Lira due to extreme climate events. Climate change was found to affect food prices in such a way that when agricultural inputs are bought expensively, it leads the cost of producing crops to increase, which in turn makes food more expensive at the market. The findings also displayed that Lira’s local communities are trying to apply adaptive farming practices to ensure there is an adequate food supply, such as planting a local variety of seeds that withstand the effect of climate change, such as sorghum millet and cassava. Based on the findings, valuable recommendations are offered. These include the government rolling out a national irrigation scheme to ease the use of the drip irrigation mechanism. Also, there is a need for more interventions that support local resilience mechanisms such as the use of agricultural inputs, as these require subsidisation. It emerged from the findings of this study that there is a need for better interventions to deal with flooding. For future researchers, it was found that there is a need to explore the best post-harvest handling methods as well as food storage. , Thesis (MA) -- Faculty of Business and Economic Sciences, 2022
- Full Text:
- Date Issued: 2022-04
IL-4/ IL-13 directed microglial activation and differentiation in response to LPS-induced neuroinflammation
- Authors: Ackerdien, Shiraz
- Date: 2024-04
- Subjects: Inflammation , Inflammation -- Treatment , Anti-inflammatory agents
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63606 , vital:73554
- Description: Microglia activation is a common hallmark of neuroinflammation that occurs during pathogen invasion or lipopolysaccharide (LPS)-induced inflammation. A neuroinflammatory response is elicited by the release of proinflammatory cytokines which stimulates microglia in an autocrine manner to be polarized into classically activated, pro-inflammatory M1 cells. Prolonged exposure to the inflammatory response can have disastrous effects on the central nervous system (CNS). However, microglia can alternatively be polarized into the activated M2 anti-inflammatory phenotype, but the exact molecular mechanism mediating this phenotypic switch remains poorly understood. Studies have shown that interleukin (IL)-4 can induce the M2 phenotype and activate the signal transducer and activator of the transcription 6 (STAT6) signalling pathway that in turn provokes a beneficial Th2 immune response. Since IL-4 and IL-13 share a common IL-4 receptor alpha (IL-4Rα) chain, it is possible that alternative microglia differentiation and its anti-inflammatory action also involve IL-13. This study aimed to investigate how IL-13 and STAT6 signalling orchestrates the microglial response and differentiation associated with LPS-induced inflammation. Furthermore, the molecular mechanisms that relieve LPS-induced neuroinflammation and neural protection through IL-13-enhanced BDNF signalling were also investigated. C8-B4 microglial cells were induced with LPS to exhibit an M1 pro-inflammatory phenotype or stimulated with IL-4 and/or IL-13 to exhibit an M2 anti-inflammatory microglial phenotype. The cell viability following LPS, IL-4, and/ or IL-13 exposure was determined. The LPS-induced neuroinflammatory response and the anti-inflammatory response induced by IL-4 and IL-13 which promotes STAT-6 signalling were determined by measuring TNFα, IL-1β, and BDNF protein concentrations using ELISA assays. The polarising effects of LPS and IL-4/IL-13 cytokines were also examined via changes in the expression of Iba-1, CD206, CD86, and STAT-6 determined by immunofluorescence analysis. These changes were further investigated by quantifying the mRNA transcripts of TNFα, IL-1 β, Arg-1, CD206, IL-4R, and STAT-6 and BDNF using qRT-PCR. , Thesis (MSc) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 2024
- Full Text:
- Date Issued: 2024-04
- Authors: Ackerdien, Shiraz
- Date: 2024-04
- Subjects: Inflammation , Inflammation -- Treatment , Anti-inflammatory agents
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63606 , vital:73554
- Description: Microglia activation is a common hallmark of neuroinflammation that occurs during pathogen invasion or lipopolysaccharide (LPS)-induced inflammation. A neuroinflammatory response is elicited by the release of proinflammatory cytokines which stimulates microglia in an autocrine manner to be polarized into classically activated, pro-inflammatory M1 cells. Prolonged exposure to the inflammatory response can have disastrous effects on the central nervous system (CNS). However, microglia can alternatively be polarized into the activated M2 anti-inflammatory phenotype, but the exact molecular mechanism mediating this phenotypic switch remains poorly understood. Studies have shown that interleukin (IL)-4 can induce the M2 phenotype and activate the signal transducer and activator of the transcription 6 (STAT6) signalling pathway that in turn provokes a beneficial Th2 immune response. Since IL-4 and IL-13 share a common IL-4 receptor alpha (IL-4Rα) chain, it is possible that alternative microglia differentiation and its anti-inflammatory action also involve IL-13. This study aimed to investigate how IL-13 and STAT6 signalling orchestrates the microglial response and differentiation associated with LPS-induced inflammation. Furthermore, the molecular mechanisms that relieve LPS-induced neuroinflammation and neural protection through IL-13-enhanced BDNF signalling were also investigated. C8-B4 microglial cells were induced with LPS to exhibit an M1 pro-inflammatory phenotype or stimulated with IL-4 and/or IL-13 to exhibit an M2 anti-inflammatory microglial phenotype. The cell viability following LPS, IL-4, and/ or IL-13 exposure was determined. The LPS-induced neuroinflammatory response and the anti-inflammatory response induced by IL-4 and IL-13 which promotes STAT-6 signalling were determined by measuring TNFα, IL-1β, and BDNF protein concentrations using ELISA assays. The polarising effects of LPS and IL-4/IL-13 cytokines were also examined via changes in the expression of Iba-1, CD206, CD86, and STAT-6 determined by immunofluorescence analysis. These changes were further investigated by quantifying the mRNA transcripts of TNFα, IL-1 β, Arg-1, CD206, IL-4R, and STAT-6 and BDNF using qRT-PCR. , Thesis (MSc) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 2024
- Full Text:
- Date Issued: 2024-04
The use of a rapid incineration field test for determining soil organic carbon in the Southern Cape Region
- Authors: Ackhurst, Albert Arthur
- Date: 2014-12
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/53336 , vital:45135
- Description: Knowledge of soil organic carbon levels is important both for agricultural effectiveness and soil carbon sequestration accounting, especially against the backdrop of increased climate change impacts and pressure on food production landscapes. However, current methods for soil carbon determination are expensive, energy intensive, time consuming and potentially hazardous leading to a call for alternative methods, which should be cheap, fast, simple, accurate, safe and usable where resources and soil analysis laboratories are limited. To this end the student invented a novel rapid incineration field test (RIFT) for determining soil organic carbon and tested its validity in this study. This method incorporates principles found in dry combustion as well as loss-on-ignition and quantifying organic carbon through gravimetric analysis. In order to illustrate effectiveness and accuracy it was necessary to correlate RIFT with a reference method, in this instance dry combustion with a Leco device as well as another commonly used indirect method namely the Walkley-Black wet chemical oxidation method. Samples from eleven soil forms were collected from the Southern Cape region and they were subjected to the three testing methods. It was found that RIFT is indeed as effective and in 72% of the soil forms even more effective than Walkley-Black. Furthermore, it was ascertained whether the accuracy of RIFT can be improved by correcting for clay content. The correlation of RIFT with clay % was not very significant and clay % as a variable was therefore not used in this study to obtain further refinement of RIFT predictions. Another finding was also that RIFT illustrated less variability than both the Leco and Walkley-Black methods. Lastly it was ascertained that the RIFT device and methodology is indeed cost effective, energy efficient, fast and safe in terms of the need to use potentially hazardous chemicals. , Thesis (MA) -- Faculty of Science, School of Natural Resource Management, 2021
- Full Text:
- Date Issued: 2014-12
- Authors: Ackhurst, Albert Arthur
- Date: 2014-12
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/53336 , vital:45135
- Description: Knowledge of soil organic carbon levels is important both for agricultural effectiveness and soil carbon sequestration accounting, especially against the backdrop of increased climate change impacts and pressure on food production landscapes. However, current methods for soil carbon determination are expensive, energy intensive, time consuming and potentially hazardous leading to a call for alternative methods, which should be cheap, fast, simple, accurate, safe and usable where resources and soil analysis laboratories are limited. To this end the student invented a novel rapid incineration field test (RIFT) for determining soil organic carbon and tested its validity in this study. This method incorporates principles found in dry combustion as well as loss-on-ignition and quantifying organic carbon through gravimetric analysis. In order to illustrate effectiveness and accuracy it was necessary to correlate RIFT with a reference method, in this instance dry combustion with a Leco device as well as another commonly used indirect method namely the Walkley-Black wet chemical oxidation method. Samples from eleven soil forms were collected from the Southern Cape region and they were subjected to the three testing methods. It was found that RIFT is indeed as effective and in 72% of the soil forms even more effective than Walkley-Black. Furthermore, it was ascertained whether the accuracy of RIFT can be improved by correcting for clay content. The correlation of RIFT with clay % was not very significant and clay % as a variable was therefore not used in this study to obtain further refinement of RIFT predictions. Another finding was also that RIFT illustrated less variability than both the Leco and Walkley-Black methods. Lastly it was ascertained that the RIFT device and methodology is indeed cost effective, energy efficient, fast and safe in terms of the need to use potentially hazardous chemicals. , Thesis (MA) -- Faculty of Science, School of Natural Resource Management, 2021
- Full Text:
- Date Issued: 2014-12
Investigation of the host potential of compounds derived from tartaric acid, succinic acid and 1,4-cyclohexanedioic acid
- Authors: Adam, Muhammad Ameen
- Date: 2024-04
- Subjects: Chemical reactions , Chemistry, Organic , Bacteriology
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63617 , vital:73562
- Description: The present investigation considered the host behaviour of three compounds, namely (+)-(2R,3R)-1,1,4,4-tetraphenylbutane-1,2,3,4-tetraol (H1), 1,1,4,4-tetraphenyl-1,4-butanediol (H2) and cyclohexane-1,4-diylbis(diphenylmethanol) (H3) in various guest mixtures. These host compounds were readily synthesized by means of Grignard addition reactions on the diesters of tartaric acid, succinic acid and 1,4-cyclohexanedioic acid. The guest mixtures included cyclopentanone, cyclohexanone, cycloheptanone and cyclooctanone, γ-butyrolactone, 2-pyrrolidone, N-methyl-2-pyrrolidone and N-ethyl-2-pyrrolidone, and pyridine, 2-methylpyridine, 3-methylpyridine and 4-methylpyridine. Crystals of (+)-(2R,3R)-1,1,4,4-tetraphenylbutane-1,2,3,4-tetraol (H1) were grown from cyclopentanone (5-ONE), cyclohexanone (6-ONE), cycloheptanone (7-ONE) and cyclooctanone (8-ONE,) producing 1:1 host:guest complexes in each instance. Thermal analysis showed the thermal stabilities of these complexes to be in the order 6-ONE > 7-ONE > 8-ONE > 5-ONE which correlated exactly with results from binary guest/guest competition experiments, where 6-ONE was always preferred by H1, while 5-ONE was consistently disfavoured. Single crystal X-ray diffraction (SCXRD) analyses demonstrated that each guest compound was retained in the crystals by means of a hydrogen bond with an alcohol moiety of the host compound. Furthermore, preferred guests 6- and 7-ONE produced crystals with greater densities than guests less favoured (5- and 8-ONE). A conformational analysis of the guest geometries in the four complexes with H1 revealed that the low energy guest conformers were present. The host selectivity for 6- and 7-ONE was proposed to be due to the improved molecular packing in the crystals of the complexes containing these two guest compounds, observed from their higher crystal densities. Hirshfeld surface analyses were not useful in explaining the preference of H1 for 6-ONE relative to 7-ONE (these types of analyses were not possible for the 5-ONE and 8-ONE-containing inclusion compounds due to the nature and degree of disorder present in the guest molecules). H1 was also crystallized from γ-butyrolactone (GBL), 2-pyrrolidone (NP), N-methyl-2-pyrrolidone (NMP) and N-ethyl-2-pyrrolidone (NEP), and 1H-NMR spectroscopy revealed that all but GBL were included. The host compound was also presented with these guest solvents in various mixtures, and it was observed that NMP was an extremely favoured guest solvent, followed by NEP and NP, with GBL being consistently disfavoured in every experiment. It was therefore shown that in certain instances, H1 may serve as an alternative tool for separating some of these mixtures through host-guest chemistry strategies. The hydrogen bonding motifs present in each of the successfully formed complexes were extensively investigated through SCXRD analysis, as was the thermal behaviour of these complexes. In the latter instance, the peak temperature of the endotherm (from the DSC trace) representing the guest release was greater for the inclusion compound with favoured NMP (145.5 °C) relative to the complexes with NP (139.8 °C) and NEP (120.5 °C). Host compounds H2 and H3 were revealed to have the ability to include each of pyridine (PYR), 2-methylpyridine (2MP), 3-methylpyridine (3MP) and 4-methylpyridine (4MP). H2 displayed selective behaviour for 3MP and 4MP when presented with mixtures of these guest compounds, whilst H3 preferred PYR. In the latter case, this PYR-containing inclusion compound was also the more stable one (the guest release onset temperature was highest, Ton 66.0 °C). It was demonstrated that H2 has the ability to separate very many binary mixtures of these pyridines on a practical platform, since K (the selectivity coefficient) values were 10 or greater in many instances. However, unfortunately, the more difficult-to-separate mixtures containing 3MP and 4MP cannot be purified or separated by employing H2 and supramolecular chemistry strategies. H3 was also shown to be a likely candidate for binary guest separations in very many of the guest solutions considered here, where K was also 10 or greater, and even infinity in many cases. SCXRD demonstrated that 2MP, 3MP and 4MP were retained in the crystals of their complexes by means of classical hydrogen bonds with the host compound. Satisfyingly, this hydrogen bond between 2MP and H2 (3.0213(18) Å) was significantly longer than that between this host compound and both disorder components of 3MP (2.875(2) and 2.825(9) Å) and that between H2 and 4MP (2.8458(13) Å). This observation explains the affinity of H2 for both 3MP and 4MP, and why 2MP was disfavoured. The results of thermal experiments did not wholly concur with observations from the guest/guest competition experiments. Hirshfeld surface analyses were also conducted but were not entirely conclusive with respect to explaining the host selectivity behaviour. In the case of H3, SCXRD analyses revealed that favoured PYR experienced a classical hydrogen bond with the host compound that was statistically significantly shorter (2.795(2) Å, 165°) than those between the other guest compounds and H3. Additionally, this guest compound was the only one to be involved in a (host)C−H···π(guest) interaction (2.91 Å, 139°) and also a non-classical hydrogen bond with the host compound ((host)C−H···N−C(guest), 2.77 Å (144°)). Finally, Hirshfeld surface analyses showed also that preferred PYR experienced a greater percentage of C···H/H···C (33.1%) and H···N/N···H (11.1%) interactions compared with the complexes with 2MP, 3MP and 4MP. However, it is not clear whether these Hirshfeld observations explain the affinity of H3 for PYR. , Thesis (MSc) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 2024
- Full Text:
- Date Issued: 2024-04
- Authors: Adam, Muhammad Ameen
- Date: 2024-04
- Subjects: Chemical reactions , Chemistry, Organic , Bacteriology
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63617 , vital:73562
- Description: The present investigation considered the host behaviour of three compounds, namely (+)-(2R,3R)-1,1,4,4-tetraphenylbutane-1,2,3,4-tetraol (H1), 1,1,4,4-tetraphenyl-1,4-butanediol (H2) and cyclohexane-1,4-diylbis(diphenylmethanol) (H3) in various guest mixtures. These host compounds were readily synthesized by means of Grignard addition reactions on the diesters of tartaric acid, succinic acid and 1,4-cyclohexanedioic acid. The guest mixtures included cyclopentanone, cyclohexanone, cycloheptanone and cyclooctanone, γ-butyrolactone, 2-pyrrolidone, N-methyl-2-pyrrolidone and N-ethyl-2-pyrrolidone, and pyridine, 2-methylpyridine, 3-methylpyridine and 4-methylpyridine. Crystals of (+)-(2R,3R)-1,1,4,4-tetraphenylbutane-1,2,3,4-tetraol (H1) were grown from cyclopentanone (5-ONE), cyclohexanone (6-ONE), cycloheptanone (7-ONE) and cyclooctanone (8-ONE,) producing 1:1 host:guest complexes in each instance. Thermal analysis showed the thermal stabilities of these complexes to be in the order 6-ONE > 7-ONE > 8-ONE > 5-ONE which correlated exactly with results from binary guest/guest competition experiments, where 6-ONE was always preferred by H1, while 5-ONE was consistently disfavoured. Single crystal X-ray diffraction (SCXRD) analyses demonstrated that each guest compound was retained in the crystals by means of a hydrogen bond with an alcohol moiety of the host compound. Furthermore, preferred guests 6- and 7-ONE produced crystals with greater densities than guests less favoured (5- and 8-ONE). A conformational analysis of the guest geometries in the four complexes with H1 revealed that the low energy guest conformers were present. The host selectivity for 6- and 7-ONE was proposed to be due to the improved molecular packing in the crystals of the complexes containing these two guest compounds, observed from their higher crystal densities. Hirshfeld surface analyses were not useful in explaining the preference of H1 for 6-ONE relative to 7-ONE (these types of analyses were not possible for the 5-ONE and 8-ONE-containing inclusion compounds due to the nature and degree of disorder present in the guest molecules). H1 was also crystallized from γ-butyrolactone (GBL), 2-pyrrolidone (NP), N-methyl-2-pyrrolidone (NMP) and N-ethyl-2-pyrrolidone (NEP), and 1H-NMR spectroscopy revealed that all but GBL were included. The host compound was also presented with these guest solvents in various mixtures, and it was observed that NMP was an extremely favoured guest solvent, followed by NEP and NP, with GBL being consistently disfavoured in every experiment. It was therefore shown that in certain instances, H1 may serve as an alternative tool for separating some of these mixtures through host-guest chemistry strategies. The hydrogen bonding motifs present in each of the successfully formed complexes were extensively investigated through SCXRD analysis, as was the thermal behaviour of these complexes. In the latter instance, the peak temperature of the endotherm (from the DSC trace) representing the guest release was greater for the inclusion compound with favoured NMP (145.5 °C) relative to the complexes with NP (139.8 °C) and NEP (120.5 °C). Host compounds H2 and H3 were revealed to have the ability to include each of pyridine (PYR), 2-methylpyridine (2MP), 3-methylpyridine (3MP) and 4-methylpyridine (4MP). H2 displayed selective behaviour for 3MP and 4MP when presented with mixtures of these guest compounds, whilst H3 preferred PYR. In the latter case, this PYR-containing inclusion compound was also the more stable one (the guest release onset temperature was highest, Ton 66.0 °C). It was demonstrated that H2 has the ability to separate very many binary mixtures of these pyridines on a practical platform, since K (the selectivity coefficient) values were 10 or greater in many instances. However, unfortunately, the more difficult-to-separate mixtures containing 3MP and 4MP cannot be purified or separated by employing H2 and supramolecular chemistry strategies. H3 was also shown to be a likely candidate for binary guest separations in very many of the guest solutions considered here, where K was also 10 or greater, and even infinity in many cases. SCXRD demonstrated that 2MP, 3MP and 4MP were retained in the crystals of their complexes by means of classical hydrogen bonds with the host compound. Satisfyingly, this hydrogen bond between 2MP and H2 (3.0213(18) Å) was significantly longer than that between this host compound and both disorder components of 3MP (2.875(2) and 2.825(9) Å) and that between H2 and 4MP (2.8458(13) Å). This observation explains the affinity of H2 for both 3MP and 4MP, and why 2MP was disfavoured. The results of thermal experiments did not wholly concur with observations from the guest/guest competition experiments. Hirshfeld surface analyses were also conducted but were not entirely conclusive with respect to explaining the host selectivity behaviour. In the case of H3, SCXRD analyses revealed that favoured PYR experienced a classical hydrogen bond with the host compound that was statistically significantly shorter (2.795(2) Å, 165°) than those between the other guest compounds and H3. Additionally, this guest compound was the only one to be involved in a (host)C−H···π(guest) interaction (2.91 Å, 139°) and also a non-classical hydrogen bond with the host compound ((host)C−H···N−C(guest), 2.77 Å (144°)). Finally, Hirshfeld surface analyses showed also that preferred PYR experienced a greater percentage of C···H/H···C (33.1%) and H···N/N···H (11.1%) interactions compared with the complexes with 2MP, 3MP and 4MP. However, it is not clear whether these Hirshfeld observations explain the affinity of H3 for PYR. , Thesis (MSc) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 2024
- Full Text:
- Date Issued: 2024-04
Exploring recurring dreams as a catalyst for image-making in Visual Art
- Authors: Adams, Demi
- Date: 2021-04
- Subjects: Dreams and the arts , Dreams in motion pictures
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52424 , vital:43640
- Description: The purpose of this study was to create a body of work which focused on the recurring dreams I have been experiencing since early childhood. I had dreams about a world which I could access through the back of my bedroom cupboard or a crack in my ceiling. This world is one which never experiences daytime; it is covered in various crystals and has its own inhabitants. I started keeping dream diaries to create my artworks, essentially creating a Paracosm. Paracosm is: “… a detailed imaginary world, especially one created by a child” (Your dictionary, 2020: 1). The problem of this study was thus: was it possible to recreate my Crystal-Lunar World (personal dream narrative) using visual art so others could experience it and which methods should be employed to substantiate these recurring dreams. Thus, the overarching research question is how do recurring personal dreams translate into visual art to sustain a language which manifests in an individual visual narrative. I made use of mixed media paintings and three-dimensional objects to illustrate scenes from my Crystal-Lunar World. I kept Dream Diaries to collect data on my recurring dreams and extract frequencies and group them into themes to create my artworks. The dream diaries also substantiated what I was painting and making. I also kept drawing journals to study the various crystals and to illustrate them and the creatures I see. , Thesis (MA) -- Faculty of Humanities, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Adams, Demi
- Date: 2021-04
- Subjects: Dreams and the arts , Dreams in motion pictures
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52424 , vital:43640
- Description: The purpose of this study was to create a body of work which focused on the recurring dreams I have been experiencing since early childhood. I had dreams about a world which I could access through the back of my bedroom cupboard or a crack in my ceiling. This world is one which never experiences daytime; it is covered in various crystals and has its own inhabitants. I started keeping dream diaries to create my artworks, essentially creating a Paracosm. Paracosm is: “… a detailed imaginary world, especially one created by a child” (Your dictionary, 2020: 1). The problem of this study was thus: was it possible to recreate my Crystal-Lunar World (personal dream narrative) using visual art so others could experience it and which methods should be employed to substantiate these recurring dreams. Thus, the overarching research question is how do recurring personal dreams translate into visual art to sustain a language which manifests in an individual visual narrative. I made use of mixed media paintings and three-dimensional objects to illustrate scenes from my Crystal-Lunar World. I kept Dream Diaries to collect data on my recurring dreams and extract frequencies and group them into themes to create my artworks. The dream diaries also substantiated what I was painting and making. I also kept drawing journals to study the various crystals and to illustrate them and the creatures I see. , Thesis (MA) -- Faculty of Humanities, 2021
- Full Text:
- Date Issued: 2021-04
Reasonable accommodation for persons with disabilities at the workplace
- Authors: Addae, Charles Kwadwo
- Date: 2024-04
- Subjects: Employment Equity Act 55 of 1998 , Disability rights , Disability in the work place
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/66140 , vital:74420
- Description: In recent years, there has been a growing recognition of the importance of inclusivity and equal opportunities for individuals with disabilities in the workplace. This thesis aims to contribute to this discourse by examining the issue of reasonable accommodation for disabled employees, with a specific focus on the South African context. The International Labour Organisation (ILO) and the United Nations (UN) Convention on the Rights of Persons with Disabilities provide important frameworks for promoting inclusivity and equal opportunities for disabled individuals in employment. These global standards emphasise the need for reasonable accommodation, which refers to the adjustments and modifications made to the work environment or job duties to enable disabled employees to perform their tasks effectively. In South Africa, the Employment Equity Act 55 of 1998 (EEA) and the Labour Relations Act 66 of 1995 (LRA) serve as the legal framework for addressing disability rights in the workplace. These acts outline the obligations of employers to provide reasonable accommodation and protect disabled employees from discrimination. By analysing the specific provisions within the EEA and LRA, this research aims to gain insights into how South Africa addresses and implements reasonable accommodation measures. By synthesizing the perspectives of the ILO, the UN Convention, and the South African legal framework, this study aims to provide a comprehensive understanding of the challenges, successes, and potential areas for improvement in achieving workplace inclusivity for individuals with disabilities. It will examine the barriers that disabled employees face in accessing reasonable accommodation, such as attitudinal barriers, lack of awareness, and financial constraints. Additionally, it will explore the strategies and initiatives that have been successful in promoting inclusivity and equal opportunities for disabled individuals in the South African workplace. , Thesis (MSc) -- Faculty of Law, Department of Mercantile law, 2024
- Full Text:
- Date Issued: 2024-04
- Authors: Addae, Charles Kwadwo
- Date: 2024-04
- Subjects: Employment Equity Act 55 of 1998 , Disability rights , Disability in the work place
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/66140 , vital:74420
- Description: In recent years, there has been a growing recognition of the importance of inclusivity and equal opportunities for individuals with disabilities in the workplace. This thesis aims to contribute to this discourse by examining the issue of reasonable accommodation for disabled employees, with a specific focus on the South African context. The International Labour Organisation (ILO) and the United Nations (UN) Convention on the Rights of Persons with Disabilities provide important frameworks for promoting inclusivity and equal opportunities for disabled individuals in employment. These global standards emphasise the need for reasonable accommodation, which refers to the adjustments and modifications made to the work environment or job duties to enable disabled employees to perform their tasks effectively. In South Africa, the Employment Equity Act 55 of 1998 (EEA) and the Labour Relations Act 66 of 1995 (LRA) serve as the legal framework for addressing disability rights in the workplace. These acts outline the obligations of employers to provide reasonable accommodation and protect disabled employees from discrimination. By analysing the specific provisions within the EEA and LRA, this research aims to gain insights into how South Africa addresses and implements reasonable accommodation measures. By synthesizing the perspectives of the ILO, the UN Convention, and the South African legal framework, this study aims to provide a comprehensive understanding of the challenges, successes, and potential areas for improvement in achieving workplace inclusivity for individuals with disabilities. It will examine the barriers that disabled employees face in accessing reasonable accommodation, such as attitudinal barriers, lack of awareness, and financial constraints. Additionally, it will explore the strategies and initiatives that have been successful in promoting inclusivity and equal opportunities for disabled individuals in the South African workplace. , Thesis (MSc) -- Faculty of Law, Department of Mercantile law, 2024
- Full Text:
- Date Issued: 2024-04
Parents’ involvement in education of their children: case study of two selected secondary schools in the Amathole West District
- Authors: Adelabu, O J
- Date: 2020-10
- Subjects: Education -- Parent participation , Parent-teacher relationships
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/19969 , vital:44857
- Description: Parents’ involvement is a very important element that has an influence on children’s education. However, research has shown that parents’ involvement is the biggest challenge facing South African schools. The study sought to investigate parents’ involvement in the education of their children at secondary school in Amathole West District, Eastern Cape Province of South Africa. The study was underpinned by Epstein’s theory of parental involvement and the Ecological framework. A qualitative approach was adopted in this study which was located within an interpretivist paradigm and used a case study approach with a sample of 26 participants which includes (2 school principals, 6 educators, 6 parents and 12 learners) were selected conveniently, data was collected using focus group discussions, interviews and document analysis. The study revealed that although schools have employed various strategies to improve parental involvement in their children’s education, there are still challenges which inhibit the effectiveness of these strategies. The study also revealed that most parents are unable to get involved as expected by the school due to some challenges such as poverty, unemployment, educational background, distance and illiteracy. Consequently, the study recommended that parents must be more actively involved in the school and collaborate with their children’s teacher in order to bring out the best in their children. Furthermore, to ensure effective parents’ involvement, schools may have activities that can develop, improve and encourage parents’ involvement in such areas as parenting, communication, learning at home, volunteering, decision making and community collaboration. , Thesis (MEd) -- Faculty of Education, 2020
- Full Text:
- Date Issued: 2020-10
- Authors: Adelabu, O J
- Date: 2020-10
- Subjects: Education -- Parent participation , Parent-teacher relationships
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/19969 , vital:44857
- Description: Parents’ involvement is a very important element that has an influence on children’s education. However, research has shown that parents’ involvement is the biggest challenge facing South African schools. The study sought to investigate parents’ involvement in the education of their children at secondary school in Amathole West District, Eastern Cape Province of South Africa. The study was underpinned by Epstein’s theory of parental involvement and the Ecological framework. A qualitative approach was adopted in this study which was located within an interpretivist paradigm and used a case study approach with a sample of 26 participants which includes (2 school principals, 6 educators, 6 parents and 12 learners) were selected conveniently, data was collected using focus group discussions, interviews and document analysis. The study revealed that although schools have employed various strategies to improve parental involvement in their children’s education, there are still challenges which inhibit the effectiveness of these strategies. The study also revealed that most parents are unable to get involved as expected by the school due to some challenges such as poverty, unemployment, educational background, distance and illiteracy. Consequently, the study recommended that parents must be more actively involved in the school and collaborate with their children’s teacher in order to bring out the best in their children. Furthermore, to ensure effective parents’ involvement, schools may have activities that can develop, improve and encourage parents’ involvement in such areas as parenting, communication, learning at home, volunteering, decision making and community collaboration. , Thesis (MEd) -- Faculty of Education, 2020
- Full Text:
- Date Issued: 2020-10
Ultraprecision Diamond Turning of Monocrystalline Germanium
- Authors: Adeleke, Adeniyi Kehinde
- Date: 2021-04
- Subjects: Precision , Diamond Turning
- Language: English
- Type: Master's theses , Thesis
- Identifier: http://hdl.handle.net/10948/44453 , vital:37835
- Description: Infrared lens production demands a surface with a high degree of accuracy and integrity. Surface roughness is a critical index of the measure of any product’s surface integrity. As a result of this, ultra-high machining technology has enjoyed extensive application, due to the continuous request for components within the range of 1 – 10nm roughness value. This technology has brought about the increased productivity and manufacture of quality products with a top-notch surface finish. Brittle materials such as germanium are hard to machine through the conventional processes such as lapping and polishing. Hence, the ultra-precision machining technology based on single point diamond turning (SPDT), is now been applied to machine germanium in the ductile mode, where material chip removal occurs by plastic deformation instead of a brittle fracture. During machining, selecting the optimal cutting conditions which includes cutting parameters and tool geometry, will not only improve productivity but ensure the minimisation of operating cost. In this research work, SPDT operation was used to conduct two experiments on a (monocrystalline germanium) workpiece. The first experiment was carried out using a diamond tool with a 1.5 mm nose radius, while the second experiment employed the use of a tool having a nose radius of 1.0 mm. A combination of machining parameters for each of the experimental runs were derived from a Box-Behnken method of design and the surface roughness was measured at each interval for both experiments with the aid of a Taylor Hopson PGI Dimension XL profilometer. Acoustic emission (AE) was also used as a quality sensing and tool-monitoring technique, to acquire signals and give indications of the expected surface roughness. Predictive models based on response surface methodology (RSM) and artificial neural networks (ANN), were developed for determining surface roughness. Optimisation was performed using RSM to determine the optimal set of machining factors, which results in optimal condition of the output response. Further investigations on the acquired signals were carried out using signal-processing techniques. Time-domain and time-frequency domain features acquired from the AE signals, together with the process parameters, were employed as input variables in the neural network design, having shown a good association with the surface roughness. ix Conclusively, it can be observed that the predictive model results and the experimental roughness measurements are in good agreement with each other. For accuracy and cost of computation, the RSM and ANN developed models for single-crystal germanium are compared using mean absolute error (MAE). , Thesis (M.Eng) -- Faculty of Engineering, the built environment & Information Technology, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Adeleke, Adeniyi Kehinde
- Date: 2021-04
- Subjects: Precision , Diamond Turning
- Language: English
- Type: Master's theses , Thesis
- Identifier: http://hdl.handle.net/10948/44453 , vital:37835
- Description: Infrared lens production demands a surface with a high degree of accuracy and integrity. Surface roughness is a critical index of the measure of any product’s surface integrity. As a result of this, ultra-high machining technology has enjoyed extensive application, due to the continuous request for components within the range of 1 – 10nm roughness value. This technology has brought about the increased productivity and manufacture of quality products with a top-notch surface finish. Brittle materials such as germanium are hard to machine through the conventional processes such as lapping and polishing. Hence, the ultra-precision machining technology based on single point diamond turning (SPDT), is now been applied to machine germanium in the ductile mode, where material chip removal occurs by plastic deformation instead of a brittle fracture. During machining, selecting the optimal cutting conditions which includes cutting parameters and tool geometry, will not only improve productivity but ensure the minimisation of operating cost. In this research work, SPDT operation was used to conduct two experiments on a (monocrystalline germanium) workpiece. The first experiment was carried out using a diamond tool with a 1.5 mm nose radius, while the second experiment employed the use of a tool having a nose radius of 1.0 mm. A combination of machining parameters for each of the experimental runs were derived from a Box-Behnken method of design and the surface roughness was measured at each interval for both experiments with the aid of a Taylor Hopson PGI Dimension XL profilometer. Acoustic emission (AE) was also used as a quality sensing and tool-monitoring technique, to acquire signals and give indications of the expected surface roughness. Predictive models based on response surface methodology (RSM) and artificial neural networks (ANN), were developed for determining surface roughness. Optimisation was performed using RSM to determine the optimal set of machining factors, which results in optimal condition of the output response. Further investigations on the acquired signals were carried out using signal-processing techniques. Time-domain and time-frequency domain features acquired from the AE signals, together with the process parameters, were employed as input variables in the neural network design, having shown a good association with the surface roughness. ix Conclusively, it can be observed that the predictive model results and the experimental roughness measurements are in good agreement with each other. For accuracy and cost of computation, the RSM and ANN developed models for single-crystal germanium are compared using mean absolute error (MAE). , Thesis (M.Eng) -- Faculty of Engineering, the built environment & Information Technology, 2021
- Full Text:
- Date Issued: 2021-04
The factors that contribute to students’ positive perceptions towards service quality in selected off-campus residences in Nelson Mandela Bay
- Authors: Adeleke, Thobile
- Date: 2021-04
- Subjects: SERVQUAL (Service quality framework) , Student housing -- Resident satisfaction -- South Africa , Consumer satisfaction -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/50922 , vital:43172
- Description: Post 1994 in South Africa there has been a notable increase in the number of students enrolled at different universities which offer student accommodation. Unfortunately, only 20% of the students can be accommodated in on-campus university accommodation, which results in most students seeking accommodation in off-campus student residences many of whom do not meet the quality requirements stipulated by the Department of Higher Education. This is what prompted this research study, whose aim was to investigate the perceptions of NMU students residing in off-campus residence, towards service quality. A literature review was conducted and focused on the service quality construct, delved into the definitions of services and quality and their benefits in all industries as well as within the student housing context. The different theoretical models used in the evaluation of service quality i.e., SERVQUAL, SERVPERF, the Gaps Model and Gronroos Model were discussed. A questionnaire based on the modified SERVQUAL tool was utilized in the evaluation of service quality levels in accredited NMU off-campus residences in Nelson Mandela Bay. Statistical evaluations were conducted on the five dimensions of SERVQUAL, namely, reliability; responsiveness; assurance; empathy and tangibles/physical attributes. The primary objective of this research was achieved, as the perceptions of students towards service quality in off-campus student accommodation were successfully measured using the SERVQUAL tool. Three service quality dimensions, namely, assurance, empathy and tangibles received positive assessments. On the other hand, the empirical research results clearly demonstrated two factors that scored low i.e., reliability and responsiveness, which reflects the respondents’ negative perceptions towards these two factors. Practical steps must be taken by off-campus residence management to ensure that the expectations versus perception service gap highlighted by the empirical findings of this study are addressed in order to keep their customers satisfied and remain competitive. Cronbach alpha coefficients above 0.80 were obtained for all the five variables, proving the SERVQUAL instrument’s internal consistency and reliability to be very good. , Thesis (MBA) -- Faculty of Business and Economic Science, Business Administration, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Adeleke, Thobile
- Date: 2021-04
- Subjects: SERVQUAL (Service quality framework) , Student housing -- Resident satisfaction -- South Africa , Consumer satisfaction -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/50922 , vital:43172
- Description: Post 1994 in South Africa there has been a notable increase in the number of students enrolled at different universities which offer student accommodation. Unfortunately, only 20% of the students can be accommodated in on-campus university accommodation, which results in most students seeking accommodation in off-campus student residences many of whom do not meet the quality requirements stipulated by the Department of Higher Education. This is what prompted this research study, whose aim was to investigate the perceptions of NMU students residing in off-campus residence, towards service quality. A literature review was conducted and focused on the service quality construct, delved into the definitions of services and quality and their benefits in all industries as well as within the student housing context. The different theoretical models used in the evaluation of service quality i.e., SERVQUAL, SERVPERF, the Gaps Model and Gronroos Model were discussed. A questionnaire based on the modified SERVQUAL tool was utilized in the evaluation of service quality levels in accredited NMU off-campus residences in Nelson Mandela Bay. Statistical evaluations were conducted on the five dimensions of SERVQUAL, namely, reliability; responsiveness; assurance; empathy and tangibles/physical attributes. The primary objective of this research was achieved, as the perceptions of students towards service quality in off-campus student accommodation were successfully measured using the SERVQUAL tool. Three service quality dimensions, namely, assurance, empathy and tangibles received positive assessments. On the other hand, the empirical research results clearly demonstrated two factors that scored low i.e., reliability and responsiveness, which reflects the respondents’ negative perceptions towards these two factors. Practical steps must be taken by off-campus residence management to ensure that the expectations versus perception service gap highlighted by the empirical findings of this study are addressed in order to keep their customers satisfied and remain competitive. Cronbach alpha coefficients above 0.80 were obtained for all the five variables, proving the SERVQUAL instrument’s internal consistency and reliability to be very good. , Thesis (MBA) -- Faculty of Business and Economic Science, Business Administration, 2021
- Full Text:
- Date Issued: 2021-04
A best practice model for international Financial feasibility in property Development
- Authors: Adendorff, Ryan Gregg
- Date: 2022-12
- Subjects: Built environment , Real estate development
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/59348 , vital:62073
- Description: Property development is a sector which provides economic benefits to many countries worldwide. Such economic benefits are employment provision and GDP contribution to the economy. Interestingly, financial feasibility is one of the tools that can be used to ensure property development projects’ success. It has been therefore recognised that some of the property development entrepreneurs lack financial feasibility know-how which could position their property development businesses into a competitive edge and sustainability in this continuous fluctuating property market. Hence, the aim of this study was to examine the key factors and variable that drive financial feasibility in property development and generate a financial feasibility model which can be used by property development entrepreneurs to analyse the financial feasibility of property development projects. Based on the aim of this study, an extended review of the literature relating to property business, property development, demand planning and risk management within the built environment discipline was conducted in identifying factors affecting the perceived success of financial feasibility for property development projects internationally. The research reviewed literature in the property development industry by identifying the variables for profitability, outside advice, trend analysis and real estate strategies. The research methodology approach that was used for this study, a qualitative explanatory multi-case study where embedded unit of analysis and valuable insight was provided for the success of financial feasibility in property development internationally. Semistructured interviews were conducted with various industry experts as indicated below: • Project Manager at Property Company; • Project Manager at developer; • Development Manager; • Owner of Property Group; • Part time lecturer at NMU Built Environment; • Development consulting company CEO; vi • Trustgro Developments (Pty) Ltd: Managing Director; • Tswaranang Consulting – Managing Director; • Capelo Development Company (Property Development) Director; and • NMBM - Senior Director: Land Planning and Management. The interview questions and primary and secondary propositions were defined together with the validity and reliability of the research. The purpose of the qualitative research was to unravel key factors that determine the perceived success of international financial feasibility of property development projects. Replication logic was used to generalise the results and the findings of this research effort suggested that the following variables emerging from qualitative themes, positively influences the perceived success of the financial feasibility in property development projects: profitability, risk management, outside advice, trend analysis, property cycles and demand planning. The implication arising from this study is that the perceived success of international financial feasibility in property development projects has the following positive influencing factors: profitability, risk management, outside (specialist) advice, trends analysis, property cycles and demand planning which must be considered by property developers and investors to ensure the success of their property development interventions. The curriculum of property development and real estate management practice should equally take into account the afore-mentioned factors. , Thesis (MA) -- Faculty of Engineering, the Built Environment, and Technology, 2022
- Full Text:
- Date Issued: 2022-12
- Authors: Adendorff, Ryan Gregg
- Date: 2022-12
- Subjects: Built environment , Real estate development
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/59348 , vital:62073
- Description: Property development is a sector which provides economic benefits to many countries worldwide. Such economic benefits are employment provision and GDP contribution to the economy. Interestingly, financial feasibility is one of the tools that can be used to ensure property development projects’ success. It has been therefore recognised that some of the property development entrepreneurs lack financial feasibility know-how which could position their property development businesses into a competitive edge and sustainability in this continuous fluctuating property market. Hence, the aim of this study was to examine the key factors and variable that drive financial feasibility in property development and generate a financial feasibility model which can be used by property development entrepreneurs to analyse the financial feasibility of property development projects. Based on the aim of this study, an extended review of the literature relating to property business, property development, demand planning and risk management within the built environment discipline was conducted in identifying factors affecting the perceived success of financial feasibility for property development projects internationally. The research reviewed literature in the property development industry by identifying the variables for profitability, outside advice, trend analysis and real estate strategies. The research methodology approach that was used for this study, a qualitative explanatory multi-case study where embedded unit of analysis and valuable insight was provided for the success of financial feasibility in property development internationally. Semistructured interviews were conducted with various industry experts as indicated below: • Project Manager at Property Company; • Project Manager at developer; • Development Manager; • Owner of Property Group; • Part time lecturer at NMU Built Environment; • Development consulting company CEO; vi • Trustgro Developments (Pty) Ltd: Managing Director; • Tswaranang Consulting – Managing Director; • Capelo Development Company (Property Development) Director; and • NMBM - Senior Director: Land Planning and Management. The interview questions and primary and secondary propositions were defined together with the validity and reliability of the research. The purpose of the qualitative research was to unravel key factors that determine the perceived success of international financial feasibility of property development projects. Replication logic was used to generalise the results and the findings of this research effort suggested that the following variables emerging from qualitative themes, positively influences the perceived success of the financial feasibility in property development projects: profitability, risk management, outside advice, trend analysis, property cycles and demand planning. The implication arising from this study is that the perceived success of international financial feasibility in property development projects has the following positive influencing factors: profitability, risk management, outside (specialist) advice, trends analysis, property cycles and demand planning which must be considered by property developers and investors to ensure the success of their property development interventions. The curriculum of property development and real estate management practice should equally take into account the afore-mentioned factors. , Thesis (MA) -- Faculty of Engineering, the Built Environment, and Technology, 2022
- Full Text:
- Date Issued: 2022-12
Risk factors associated with developing asthma and tuberculosis: a case study of a hospital, Lagos Nigeria
- Authors: Adeniji, Tolulope Olubunmi.
- Date: 2015-01
- Subjects: Diseases -- Risk factors -- Nigeria , Tuberculosis -- Nigeria -- Epidemiology , Asthma -- Treatment -- Nigeria
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/29010 , vital:76454
- Description: The purpose of the study is to assess risk factors associated with developing asthma and tuberculosis. A quantitative study was conducted on 133 randomly selected tuberculosis respondents, 91 of whom were suffering from TB at the time of the study. 120 respondents were also selected randomly for asthma of which 82 were asthmatic. Data were collected by using a self-structured questionnaire. The statistical analysis was done with the statistical package for social sciences SPSS, version 18 using the descriptive statistics and logistic regression model. Findings from the study show that a large percentage of the participants for both diseases were male, and the carriers of the diseases were also mostly male. Amongst the factors assessed, smoking, a weak immune system and a history of contact with tuberculosis infected persons were factors independently associated with developing tuberculosis. In the case of asthma, family history, smoking and exposure to allergen irritants were the factors independently associated with developing the disease.The findings highlight the need for increasing awareness through information, education and communication to address the risk factors of tuberculosis and asthma in order to decrease the rate of outspread. Factors triggering asthma among humans should be avoided. Since tuberculosis can be contracted through person to person contact, proper sanitation and regular medical attention are advocated for safeguarding personal and public health. , Thesis (MSc) -- Faculty of Science and Agriculture, 2015
- Full Text:
- Date Issued: 2015-01
- Authors: Adeniji, Tolulope Olubunmi.
- Date: 2015-01
- Subjects: Diseases -- Risk factors -- Nigeria , Tuberculosis -- Nigeria -- Epidemiology , Asthma -- Treatment -- Nigeria
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/29010 , vital:76454
- Description: The purpose of the study is to assess risk factors associated with developing asthma and tuberculosis. A quantitative study was conducted on 133 randomly selected tuberculosis respondents, 91 of whom were suffering from TB at the time of the study. 120 respondents were also selected randomly for asthma of which 82 were asthmatic. Data were collected by using a self-structured questionnaire. The statistical analysis was done with the statistical package for social sciences SPSS, version 18 using the descriptive statistics and logistic regression model. Findings from the study show that a large percentage of the participants for both diseases were male, and the carriers of the diseases were also mostly male. Amongst the factors assessed, smoking, a weak immune system and a history of contact with tuberculosis infected persons were factors independently associated with developing tuberculosis. In the case of asthma, family history, smoking and exposure to allergen irritants were the factors independently associated with developing the disease.The findings highlight the need for increasing awareness through information, education and communication to address the risk factors of tuberculosis and asthma in order to decrease the rate of outspread. Factors triggering asthma among humans should be avoided. Since tuberculosis can be contracted through person to person contact, proper sanitation and regular medical attention are advocated for safeguarding personal and public health. , Thesis (MSc) -- Faculty of Science and Agriculture, 2015
- Full Text:
- Date Issued: 2015-01
The determinants of renewable energy in South Africa
- Authors: Adeniyi, Bamidele Ojo
- Date: 2023-12
- Subjects: Renewable energy sources -- South Africa , Power resources -- South Africa , Sustainable development -- Research -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/65503 , vital:74163
- Description: The South African energy system to date has been dominated by the high consumption of fossil fuels and the resultant greenhouse gas emissions. Aside from this, the country has continued to witness incessant power outages, a shortfall in electricity supply, and high electricity prices due to the ageing infrastructure of coal-powered plant. Meanwhile, the United Nations’s Sustainable Development Agenda mandates countries to ensure a sustainable environment by embracing affordable and clean energy in order to mitigate unfavourable climate action by 2030. The attainment of most Sustainable Development Goals depends on renewable energy development which includes solar, wind, hydro, geothermal and biomass energy among others. Therefore, an empirical study of the socio-economic and environmental determinants of renewable energy consumption in South Africa is imperative. Based on Environmental Kuznetz curve and Khan’s sustainable development theories, this study employed the Autoregressive Distributed Lag (ARDL) and Vector Autoregressive (VAR) causality methods to analyse the long-run relationship between economic, environmental and social determinants of renewable energy. The quantile regression method examined the relationship between environmental degradation and economic growth in South Africa between 1985 to 2021. The study shows a long-run relationship between renewable energy and economic factors such as gross domestic product, energy imports, and exchange rate, while gross capital formation and average electricity prices indirectly impact renewable energy consumption. Moreover, there exists a unidirectional influence between gross domestic product and real effective exchange rate to renewable energy consumption. The study suggests that more investment in renewable infrastructures and technology would improve renewable energy consumption in South Africa. The long-run result between environmental factors and renewable energy shows that fossil fuels, deforestation, and carbon dioxide emission indirectly influence renewable energy, while energy depletion increases as renewable energy consumption increases. Meanwhile, a unidirectional causality runs from renewable energy consumption to fossil fuels and carbon dioxide emissions. This suggests that renewable energy consumption would improve environmental quality in South Africa.On the relationship between social factors and renewable energy consumption, the long-run result shows that educational spending and employment rate positively increases renewable energy consumption, while per capita income and urban growth is yet to positively influence renewable energy. Moreover, a bidirectional causal relationship exists between employment rate and renewable energy consumption. This suggests that renewable energy would create job opportunity or the other way round vice versa in South Africa. There is a positive relationship between environmental degradation and economic growth between quantile 10th to 75th, with a quick negative turning seen higher, at quantile 90th. The growth of per capita income also shows a positive relationship at the lower quantile, while an inverse relationship was seen at the higher quantile of 50th to 99th. Non-renewable energy shows a significant and positive relationship to carbon dioxide emission across the quantile curve, while renewable energy shows an inverse relationship to carbon dioxide emissions across the quantile curve; and a quick turn from 25th quantile showing that urban growth does not positively influence renewable energy. This suggests that non-renewable energy use damages the environment, while renewable energy consumption improves the quality of the environment in South Africa. The study recommends that a direct alteration of renewable energy consumption by government is a necessary condition to diffuse clean energy technology across the country. Also, increasing investment in renewable energy infrastructure through public, private and government participation is a necessary move to actualise the achievement of self-sufficiency in the renewable energy sector. Furthermore, since research is an engine room for technological innovation, government should prioritise learning in the form of research, formal and informal training, and short-term courses to equip citizens with the necessary renewable technology skills. It is hoped that the findings of this study would be beneficial to the policymakers in South Africa and also any country where renewable energy consumption is yet to be explored. , Thesis (PhD) -- Faculty of Business and Economic Sciences, School of Economics, Development and Tourism, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Adeniyi, Bamidele Ojo
- Date: 2023-12
- Subjects: Renewable energy sources -- South Africa , Power resources -- South Africa , Sustainable development -- Research -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/65503 , vital:74163
- Description: The South African energy system to date has been dominated by the high consumption of fossil fuels and the resultant greenhouse gas emissions. Aside from this, the country has continued to witness incessant power outages, a shortfall in electricity supply, and high electricity prices due to the ageing infrastructure of coal-powered plant. Meanwhile, the United Nations’s Sustainable Development Agenda mandates countries to ensure a sustainable environment by embracing affordable and clean energy in order to mitigate unfavourable climate action by 2030. The attainment of most Sustainable Development Goals depends on renewable energy development which includes solar, wind, hydro, geothermal and biomass energy among others. Therefore, an empirical study of the socio-economic and environmental determinants of renewable energy consumption in South Africa is imperative. Based on Environmental Kuznetz curve and Khan’s sustainable development theories, this study employed the Autoregressive Distributed Lag (ARDL) and Vector Autoregressive (VAR) causality methods to analyse the long-run relationship between economic, environmental and social determinants of renewable energy. The quantile regression method examined the relationship between environmental degradation and economic growth in South Africa between 1985 to 2021. The study shows a long-run relationship between renewable energy and economic factors such as gross domestic product, energy imports, and exchange rate, while gross capital formation and average electricity prices indirectly impact renewable energy consumption. Moreover, there exists a unidirectional influence between gross domestic product and real effective exchange rate to renewable energy consumption. The study suggests that more investment in renewable infrastructures and technology would improve renewable energy consumption in South Africa. The long-run result between environmental factors and renewable energy shows that fossil fuels, deforestation, and carbon dioxide emission indirectly influence renewable energy, while energy depletion increases as renewable energy consumption increases. Meanwhile, a unidirectional causality runs from renewable energy consumption to fossil fuels and carbon dioxide emissions. This suggests that renewable energy consumption would improve environmental quality in South Africa.On the relationship between social factors and renewable energy consumption, the long-run result shows that educational spending and employment rate positively increases renewable energy consumption, while per capita income and urban growth is yet to positively influence renewable energy. Moreover, a bidirectional causal relationship exists between employment rate and renewable energy consumption. This suggests that renewable energy would create job opportunity or the other way round vice versa in South Africa. There is a positive relationship between environmental degradation and economic growth between quantile 10th to 75th, with a quick negative turning seen higher, at quantile 90th. The growth of per capita income also shows a positive relationship at the lower quantile, while an inverse relationship was seen at the higher quantile of 50th to 99th. Non-renewable energy shows a significant and positive relationship to carbon dioxide emission across the quantile curve, while renewable energy shows an inverse relationship to carbon dioxide emissions across the quantile curve; and a quick turn from 25th quantile showing that urban growth does not positively influence renewable energy. This suggests that non-renewable energy use damages the environment, while renewable energy consumption improves the quality of the environment in South Africa. The study recommends that a direct alteration of renewable energy consumption by government is a necessary condition to diffuse clean energy technology across the country. Also, increasing investment in renewable energy infrastructure through public, private and government participation is a necessary move to actualise the achievement of self-sufficiency in the renewable energy sector. Furthermore, since research is an engine room for technological innovation, government should prioritise learning in the form of research, formal and informal training, and short-term courses to equip citizens with the necessary renewable technology skills. It is hoped that the findings of this study would be beneficial to the policymakers in South Africa and also any country where renewable energy consumption is yet to be explored. , Thesis (PhD) -- Faculty of Business and Economic Sciences, School of Economics, Development and Tourism, 2023
- Full Text:
- Date Issued: 2023-12
Evaluation of groundwater potential using geological and geophysical methods in the University of Fort Hare Alice Campus, Eastern Cape Province of South Africa
- Adesola, Gbenga Olamide https://orcid.org/0000-0002-4151-5305
- Authors: Adesola, Gbenga Olamide https://orcid.org/0000-0002-4151-5305
- Date: 2022-04
- Subjects: Groundwater , Geology, Structural -- South Africa , Geographical Information Systems
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22490 , vital:52344
- Description: Geological and geophysical methods were used to evaluate the groundwater potential in University of Fort Hare (Alice campus), Eastern Cape Province of South Africa. Methodologies adopted for obtaining these results included a comprehensive literature review, thin section analysis, scanning electron microscopy, Geographical Information Systems (GIS), remote sensing and geophysical investigations (magnetic survey and vertical electrical sounding). The geology of the study area belongs to the Balfour Formation, which forms part of the Beaufort Group in the Karoo Supergroup. The rocks within the study area are composed majorly of sandstone and mudstone. Lineaments were automatically extracted using the PCI Geomatica 2018 software. Fifteen samples were collected at various locations within the study area and were analyzed using the petrographic microscope while others were analyzed with the Scanning Electron Microscopic (SEM) combined with an Energy dispersive x-ray spectrometry. The results show that the rocks are fractured, porous and contained minerals such as quartz, feldspar, calcite, mica and clay minerals. The occurrence of these fractures helps to improve the groundwater storage capacity in the study area. Out of the twenty seven (27) rock samples collected in the field, ten (10) rock samples were selected for densities (dry, wet and grain densities) and porosity measurements in the laboratory. The rocks density values range from 2.5763 – 2.6978 g/cm3. The average porosities of the rocks range from 0.85 – 2.56 percent. The density of the sandstone ranges from 2.5908 – 2.6820 g/cm3 whilst the porosity range from 0.85 – 2.02 percent. The density of the mudstone ranges from 2.5763 – 2.6978 g/cm3 whilst the porosity ranges from 1.84 – 2.56 percent. About 8458 magnetic measurements were taken at about 20 m spacing along linear and non-linear paths and road. A variety of magnetic maps were generated. Several magnetic highs were observed and the linear highs were interpreted to be due to dolerite dykes whilst the broader high zones were inferred to be due to dolerite sills. These Karoo dolerites intruded the sediments at various depths and must have fractured the sediments causing them to be more porous and permeable. The depth slices of magnetic data reveal that near surface magnetic bodies occur within the depth of approximately 19 m from the surface while deep seated ones occur as deep as 31 m and maybe deeper. The knowledge of the dolerite intrusions enabled the location of drilling targets for groundwater. Electrical resistivity data were collected at 28 sites using the Schlumberger array and a maximum cable length (250 m) from the centre point which achieved a maximum depth penetration of about 70 m to 162 m. The results from 1D modelling using WINRESIST software showed that the vertical electric sounding curves are composed of HA and HK curve-types, which show four geoelectric layers. The resistivity of the first layer which is the topmost layer has values ranging from 20 - 5752 Ωm and the thickness is between 0.4 – 1.8 m. The second layer which consists of clay, mudstone and sandstone has resistivity values varying from 3 - 51 Ωm and thickness varying from 0.8 – 17.5 m. The third layer which is interpreted to be the aquiferous layer of the study area is made up majorly of sandstone with resistivity that varies from 136 – 352 Ωm and thickness range from 9.9 – 143.9 m. The fourth layer of resistivity varying from 44 to 60428 Ωm is made up of mudstone and sandstone, which are in some places intruded by dolerites. Groundwater potential is favourably high in some of the areas investigated. Furthermore, the results of the research indicated that secondary porosity is the main porosity for the reservoir rocks in the study area. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Adesola, Gbenga Olamide https://orcid.org/0000-0002-4151-5305
- Date: 2022-04
- Subjects: Groundwater , Geology, Structural -- South Africa , Geographical Information Systems
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22490 , vital:52344
- Description: Geological and geophysical methods were used to evaluate the groundwater potential in University of Fort Hare (Alice campus), Eastern Cape Province of South Africa. Methodologies adopted for obtaining these results included a comprehensive literature review, thin section analysis, scanning electron microscopy, Geographical Information Systems (GIS), remote sensing and geophysical investigations (magnetic survey and vertical electrical sounding). The geology of the study area belongs to the Balfour Formation, which forms part of the Beaufort Group in the Karoo Supergroup. The rocks within the study area are composed majorly of sandstone and mudstone. Lineaments were automatically extracted using the PCI Geomatica 2018 software. Fifteen samples were collected at various locations within the study area and were analyzed using the petrographic microscope while others were analyzed with the Scanning Electron Microscopic (SEM) combined with an Energy dispersive x-ray spectrometry. The results show that the rocks are fractured, porous and contained minerals such as quartz, feldspar, calcite, mica and clay minerals. The occurrence of these fractures helps to improve the groundwater storage capacity in the study area. Out of the twenty seven (27) rock samples collected in the field, ten (10) rock samples were selected for densities (dry, wet and grain densities) and porosity measurements in the laboratory. The rocks density values range from 2.5763 – 2.6978 g/cm3. The average porosities of the rocks range from 0.85 – 2.56 percent. The density of the sandstone ranges from 2.5908 – 2.6820 g/cm3 whilst the porosity range from 0.85 – 2.02 percent. The density of the mudstone ranges from 2.5763 – 2.6978 g/cm3 whilst the porosity ranges from 1.84 – 2.56 percent. About 8458 magnetic measurements were taken at about 20 m spacing along linear and non-linear paths and road. A variety of magnetic maps were generated. Several magnetic highs were observed and the linear highs were interpreted to be due to dolerite dykes whilst the broader high zones were inferred to be due to dolerite sills. These Karoo dolerites intruded the sediments at various depths and must have fractured the sediments causing them to be more porous and permeable. The depth slices of magnetic data reveal that near surface magnetic bodies occur within the depth of approximately 19 m from the surface while deep seated ones occur as deep as 31 m and maybe deeper. The knowledge of the dolerite intrusions enabled the location of drilling targets for groundwater. Electrical resistivity data were collected at 28 sites using the Schlumberger array and a maximum cable length (250 m) from the centre point which achieved a maximum depth penetration of about 70 m to 162 m. The results from 1D modelling using WINRESIST software showed that the vertical electric sounding curves are composed of HA and HK curve-types, which show four geoelectric layers. The resistivity of the first layer which is the topmost layer has values ranging from 20 - 5752 Ωm and the thickness is between 0.4 – 1.8 m. The second layer which consists of clay, mudstone and sandstone has resistivity values varying from 3 - 51 Ωm and thickness varying from 0.8 – 17.5 m. The third layer which is interpreted to be the aquiferous layer of the study area is made up majorly of sandstone with resistivity that varies from 136 – 352 Ωm and thickness range from 9.9 – 143.9 m. The fourth layer of resistivity varying from 44 to 60428 Ωm is made up of mudstone and sandstone, which are in some places intruded by dolerites. Groundwater potential is favourably high in some of the areas investigated. Furthermore, the results of the research indicated that secondary porosity is the main porosity for the reservoir rocks in the study area. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-04
A scoping review on problematic Internet use and Substance Use Disorder among men
- Authors: Adolph, Miché Tania
- Date: 2024-10-11
- Subjects: Internet addiction , Substance abuse , Men Mental health , Scoping review protocol , Compulsive behavior Sex differences
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/465788 , vital:76653
- Description: Problematic Internet Use (PIU) and Substance Use Disorder (SUD) interact in complex ways that influence the current mental health landscape. Concurrently, the advent of the digital era has presented new difficulties, one of which is the emergence of problematic internet use as a significant issue that negatively impacts mental health. The increasing popularity of internet use has led to an increasing number of reports highlighting the potential negative consequences of overuse, such as substance use. Thus, the study aimed to synthesise literature on problematic internet use and substance use disorder, including the way in which they affect men, given that prior research has predominantly focused on women. The methods employed follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) which is largely based on a PRISMA statement and checklist, the JBI methodological guidance, and other approaches for undertaking scoping reviews. A total of 16 studies were eligible for final review, and the themes identified from the reviewed studies were obtained using Braun and Clarke’s thematic analysis. An analysis of the articles showed a large focus on gender differences in addiction patterns, vulnerability to problematic internet use across age groups, associations between substance use and behavioural addictions, problematic internet use and mental health disorders, the psychological consequences of problematic internet use and substance use disorders, and the various risk factors associated with the development of problematic internet use and substance use disorder. A clear understanding and conceptualisation of this behavioural addiction is vital, including the development and utilisation of appropriate and validated diagnostic and screening tools to measure its presence and, in turn, address it as an emerging mental health disorder. Focus should be given to the assessment of problematic internet use by distinguishing the two different forms, namely the generalised and specific forms of problematic internet use. Additionally, given that there were very few to no qualitative studies conducted on the topic of problematic internet use, much less addressing the possible association with substance use disorder, an assessment of the individual’s experience, especially that of men, is lacking. Future research could therefore aim to incorporate more qualitative studies to address the above. Further research is also needed to clarify the nature of the relationship between problematic internet use and substance use disorder for the purpose of establishing possible causality, including the neurobiological substrates involved. , Thesis (MA) -- Faculty of Humanities, Psychology, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Adolph, Miché Tania
- Date: 2024-10-11
- Subjects: Internet addiction , Substance abuse , Men Mental health , Scoping review protocol , Compulsive behavior Sex differences
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/465788 , vital:76653
- Description: Problematic Internet Use (PIU) and Substance Use Disorder (SUD) interact in complex ways that influence the current mental health landscape. Concurrently, the advent of the digital era has presented new difficulties, one of which is the emergence of problematic internet use as a significant issue that negatively impacts mental health. The increasing popularity of internet use has led to an increasing number of reports highlighting the potential negative consequences of overuse, such as substance use. Thus, the study aimed to synthesise literature on problematic internet use and substance use disorder, including the way in which they affect men, given that prior research has predominantly focused on women. The methods employed follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) which is largely based on a PRISMA statement and checklist, the JBI methodological guidance, and other approaches for undertaking scoping reviews. A total of 16 studies were eligible for final review, and the themes identified from the reviewed studies were obtained using Braun and Clarke’s thematic analysis. An analysis of the articles showed a large focus on gender differences in addiction patterns, vulnerability to problematic internet use across age groups, associations between substance use and behavioural addictions, problematic internet use and mental health disorders, the psychological consequences of problematic internet use and substance use disorders, and the various risk factors associated with the development of problematic internet use and substance use disorder. A clear understanding and conceptualisation of this behavioural addiction is vital, including the development and utilisation of appropriate and validated diagnostic and screening tools to measure its presence and, in turn, address it as an emerging mental health disorder. Focus should be given to the assessment of problematic internet use by distinguishing the two different forms, namely the generalised and specific forms of problematic internet use. Additionally, given that there were very few to no qualitative studies conducted on the topic of problematic internet use, much less addressing the possible association with substance use disorder, an assessment of the individual’s experience, especially that of men, is lacking. Future research could therefore aim to incorporate more qualitative studies to address the above. Further research is also needed to clarify the nature of the relationship between problematic internet use and substance use disorder for the purpose of establishing possible causality, including the neurobiological substrates involved. , Thesis (MA) -- Faculty of Humanities, Psychology, 2024
- Full Text:
- Date Issued: 2024-10-11
The Effect of training and development on employee performance in the Buffalo City Municipality in the Eastern Cape of South Africa
- Authors: Adom, Richard Kwame
- Date: 2019-09
- Subjects: Employees -- Training of , Performance -- Management , Employees -- Rating of
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/20153 , vital:45377
- Description: Training and development are regarded as significant tools for any organisation to achieve the target goals and objectives. These goals and objectives are heavily and highly dependent on its workforce. In the literature, it is well documented that many organisations invest in employees’ training and development to enhance their performance and the growth of the organisation. Many organisations, however, including the Buffalo City Municipality, regard training and staff development as needless expenditure, and always do little, or make no effort to improve employees’ technical know-how. Such actions incapacitate staff to adapt to the ever-changing working environment and rapid technological innovation. This study employed purposive sampling technique to draw a sample of 70 employees from a total of 150, through structured interviews and a self-administered questionnaire, to examine the effect of training and development on employees’ performance in the Buffalo City Municipality, situated in the Eastern Cape of South Africa. The findings of the study generally revealed that training and development does not only increase employees’ performance, but assists in developing the overall personality of employees by making them more productive through building their senses of teamwork, boosting the attitude of staff which is the most critical component in attaining profit, and developing a cordial relationship and connectivity between management and the workforce. The study, therefore, recommended that the municipality, as a matter of urgency, earmarks a certain percentage of its resources for employees training and development, based on identified skills gaps to sharpen employees’ skills, competencies, capabilities and technical know-how, to capacitate them to cope with the ever-changing working environment and innovations, and to enhance their motivation, satisfaction and performance. , Thesis (MPA) -- Faculty of Management and Commerce, 2019
- Full Text:
- Date Issued: 2019-09
- Authors: Adom, Richard Kwame
- Date: 2019-09
- Subjects: Employees -- Training of , Performance -- Management , Employees -- Rating of
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/20153 , vital:45377
- Description: Training and development are regarded as significant tools for any organisation to achieve the target goals and objectives. These goals and objectives are heavily and highly dependent on its workforce. In the literature, it is well documented that many organisations invest in employees’ training and development to enhance their performance and the growth of the organisation. Many organisations, however, including the Buffalo City Municipality, regard training and staff development as needless expenditure, and always do little, or make no effort to improve employees’ technical know-how. Such actions incapacitate staff to adapt to the ever-changing working environment and rapid technological innovation. This study employed purposive sampling technique to draw a sample of 70 employees from a total of 150, through structured interviews and a self-administered questionnaire, to examine the effect of training and development on employees’ performance in the Buffalo City Municipality, situated in the Eastern Cape of South Africa. The findings of the study generally revealed that training and development does not only increase employees’ performance, but assists in developing the overall personality of employees by making them more productive through building their senses of teamwork, boosting the attitude of staff which is the most critical component in attaining profit, and developing a cordial relationship and connectivity between management and the workforce. The study, therefore, recommended that the municipality, as a matter of urgency, earmarks a certain percentage of its resources for employees training and development, based on identified skills gaps to sharpen employees’ skills, competencies, capabilities and technical know-how, to capacitate them to cope with the ever-changing working environment and innovations, and to enhance their motivation, satisfaction and performance. , Thesis (MPA) -- Faculty of Management and Commerce, 2019
- Full Text:
- Date Issued: 2019-09