The successes of infrastructure development in Nelson Mandela Bay
- Authors: Matolengwe, Nombasa
- Date: 2019
- Subjects: Infrastructure (Economics) -- South Africa -- Nelson Mandela Bay Municipality , Public works -- Finance Economic development Sustainable development -- Economic aspects
- Language: English
- Type: Thesis , Masters , MPhil
- Identifier: http://hdl.handle.net/10948/41010 , vital:36282
- Description: Lack of capacity in the former black areas of South Africa, including lack of proper infrastructure has proven to be one of the problems the country is facing. The apartheid system did not only separate the different racial groups in geographical terms, but also prevented black communities access to infrastructural services. Number of strategies have been undertaken to address the issue of infrastructure gap including Infrastructure Development Act signed by former President Jacob Zuma in 2014, the act was aimed at coordinating and facilitating public infrastructure development. Infrastructure development is significant to the National Development Plan, therefore greater levels of investment in infrastructure will continue into the future. An amount of R379 088 000 000 has been invested in infrastructure development in South African municipalities over the period of three years from 2015. The purpose of this study is to identify critical success factors of infrastructure development projects and to understand what is meant by the term project success in the local government context. The critical success factors in infrastructure development investigated in this study were identified through reviewing the existing literature on critical success factors from 1960’s to 2015, together with relevant municipal frameworks. A questionnaire was developed, focusing on factors for successful delivery of infrastructure development projects, interviews were conducted with Ward Councillors, Integrated Development Plans and Built Environment Performance Plans officials to investigate the meaning of project success in local government context. The study suggests that a project success definition in terms of local government should include community satisfaction, fulfilment of strategic objectives of the municipality and the completed project should serve the purpose it was intended for and must be bringing social change to the area it is being implemented in. The study finds no significant correlation between project success and identified individual critical success factors; however, it has been discovered that risk management, as one of the factors, has a significant positive correlation with other factors.
- Full Text:
- Date Issued: 2019
- Authors: Matolengwe, Nombasa
- Date: 2019
- Subjects: Infrastructure (Economics) -- South Africa -- Nelson Mandela Bay Municipality , Public works -- Finance Economic development Sustainable development -- Economic aspects
- Language: English
- Type: Thesis , Masters , MPhil
- Identifier: http://hdl.handle.net/10948/41010 , vital:36282
- Description: Lack of capacity in the former black areas of South Africa, including lack of proper infrastructure has proven to be one of the problems the country is facing. The apartheid system did not only separate the different racial groups in geographical terms, but also prevented black communities access to infrastructural services. Number of strategies have been undertaken to address the issue of infrastructure gap including Infrastructure Development Act signed by former President Jacob Zuma in 2014, the act was aimed at coordinating and facilitating public infrastructure development. Infrastructure development is significant to the National Development Plan, therefore greater levels of investment in infrastructure will continue into the future. An amount of R379 088 000 000 has been invested in infrastructure development in South African municipalities over the period of three years from 2015. The purpose of this study is to identify critical success factors of infrastructure development projects and to understand what is meant by the term project success in the local government context. The critical success factors in infrastructure development investigated in this study were identified through reviewing the existing literature on critical success factors from 1960’s to 2015, together with relevant municipal frameworks. A questionnaire was developed, focusing on factors for successful delivery of infrastructure development projects, interviews were conducted with Ward Councillors, Integrated Development Plans and Built Environment Performance Plans officials to investigate the meaning of project success in local government context. The study suggests that a project success definition in terms of local government should include community satisfaction, fulfilment of strategic objectives of the municipality and the completed project should serve the purpose it was intended for and must be bringing social change to the area it is being implemented in. The study finds no significant correlation between project success and identified individual critical success factors; however, it has been discovered that risk management, as one of the factors, has a significant positive correlation with other factors.
- Full Text:
- Date Issued: 2019
The suspended sediment yield and provenance of the Inxu River Catchment, Eastern Cape
- Authors: Nyamela, Namso
- Date: 2019
- Subjects: Suspended sediments -- South Africa -- Inxu River , Sedimentation and deposition -- South Africa -- Inxu River , Watershed management -- South Africa -- Inxu River , Erosion -- South Africa -- Inxu River , Soil erosion -- South Africa -- Inxu River
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/72150 , vital:30010
- Description: The excessive deposition and accumulation of suspended sediment leads to the degradation of water resources such as dams and rivers. For the purpose of preserving and protecting these resources, suspended sediment needs to be managed, and its management should be catchment-wide and catchment-specific. This is certainly the case for the eroded Inxu River Catchment, which has been identified as a major contributor of sediment to the planned Lalini Dam on the Tsitsa River (a tributary of the Mzimvubu River). Knowledge of suspended sediment flux and catchment sources will aid the design of relevant strategies to manage suspended sediment production. Suspended sediment flux was determined from sediment samples that were collected using citizen-based monitoring techniques at calendar- and event-based sampling frequency, along with discharges estimated using stage-discharge relationships. Sediment source areas were identified by determining the suspended sediment contribution from major sub-catchments and observing similarities in the characteristics of the sub-catchments that produced the most sediment. The Inxu River Catchment produced 5.5 t/ha/yr between 01 May 2016 and 30 April 2017. When compared to modelled sediment yield (7 t/ha/yr) from Le Roux et al. (2015), modelled output was not far off from the measured results and both measured and modelled results identified similar sediment source areas. Q-SSC relationships observed at the Inxu River Outlet indicated that sediment was eroded from local areas and sub-catchment sediment contribution confirmed that most of the sediment was from the lower Inxu River Catchment. Within this area, the Ncolosi and Qwakele River Sub-catchments were major sediment source areas and were subject to widespread gully erosion. Gully erosion was prominent on gentle slopes, foot slopes and valley-bottoms that have concave slope curvature and lie on the Tarkastad Formation. This Formation is associated with some of the most dispersive soils in the area. Moreover, the catchment is vulnerable to erosion due to cultivation and subsequent land abandonment, continuous grazing and dense rural populations. Other studies in the Mzimvubu catchment identified similar catchment characteristics that contribute to excessive erosion. This study has successfully measured sediment yield and identified areas that should be targeted and prioritised for rehabilitation within the Inxu River Catchment. The findings could be applied to a wider catchment scale. The study has successfully demonstrated the use of citizen-based monitoring and desktop techniques and has also identified some pitfalls of this approach.
- Full Text:
- Date Issued: 2019
- Authors: Nyamela, Namso
- Date: 2019
- Subjects: Suspended sediments -- South Africa -- Inxu River , Sedimentation and deposition -- South Africa -- Inxu River , Watershed management -- South Africa -- Inxu River , Erosion -- South Africa -- Inxu River , Soil erosion -- South Africa -- Inxu River
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/72150 , vital:30010
- Description: The excessive deposition and accumulation of suspended sediment leads to the degradation of water resources such as dams and rivers. For the purpose of preserving and protecting these resources, suspended sediment needs to be managed, and its management should be catchment-wide and catchment-specific. This is certainly the case for the eroded Inxu River Catchment, which has been identified as a major contributor of sediment to the planned Lalini Dam on the Tsitsa River (a tributary of the Mzimvubu River). Knowledge of suspended sediment flux and catchment sources will aid the design of relevant strategies to manage suspended sediment production. Suspended sediment flux was determined from sediment samples that were collected using citizen-based monitoring techniques at calendar- and event-based sampling frequency, along with discharges estimated using stage-discharge relationships. Sediment source areas were identified by determining the suspended sediment contribution from major sub-catchments and observing similarities in the characteristics of the sub-catchments that produced the most sediment. The Inxu River Catchment produced 5.5 t/ha/yr between 01 May 2016 and 30 April 2017. When compared to modelled sediment yield (7 t/ha/yr) from Le Roux et al. (2015), modelled output was not far off from the measured results and both measured and modelled results identified similar sediment source areas. Q-SSC relationships observed at the Inxu River Outlet indicated that sediment was eroded from local areas and sub-catchment sediment contribution confirmed that most of the sediment was from the lower Inxu River Catchment. Within this area, the Ncolosi and Qwakele River Sub-catchments were major sediment source areas and were subject to widespread gully erosion. Gully erosion was prominent on gentle slopes, foot slopes and valley-bottoms that have concave slope curvature and lie on the Tarkastad Formation. This Formation is associated with some of the most dispersive soils in the area. Moreover, the catchment is vulnerable to erosion due to cultivation and subsequent land abandonment, continuous grazing and dense rural populations. Other studies in the Mzimvubu catchment identified similar catchment characteristics that contribute to excessive erosion. This study has successfully measured sediment yield and identified areas that should be targeted and prioritised for rehabilitation within the Inxu River Catchment. The findings could be applied to a wider catchment scale. The study has successfully demonstrated the use of citizen-based monitoring and desktop techniques and has also identified some pitfalls of this approach.
- Full Text:
- Date Issued: 2019
The sustainability of international labour organisation’s youth empowerment programme in Harare
- Authors: Muradya, Thelma Irene
- Date: 2019
- Subjects: Youth in development -- Zimbabwe -- Harare , Youth -- Employment -- Zimbabwe -- Harare , Community development -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/41592 , vital:36543
- Description: The study evaluated the sustainability of the International Labour Organisation’s ‘Skills for youth employment and rural development’ programme in Harare. The purpose of the study was to understand the reasons behind the rise of youth unemployment despite many interventions targeting youth being implemented within the country. Youth contribute to the development of nations if presented with opportunities. Also, the economy of Zimbabwe is highly informal; hence the need to assess the long term impact made by strengthening the skills of the youth through informal apprenticeships and if there were possibilities of growth within their businesses. Sustainability issues were therefore critical in addressing problems faced by youth empowerment initiatives, so as to ensure that beneficiaries of programs attain long term benefits in future and that future programmes can also make sustainability their core focus. This mixed method study utilised interviews with youth beneficiaries and an ILO official in Harare as well as document analysis to gather data about the programme. The findings indicated that despite the programme achieving its targeted objectives and providing skills within the various sectors as well as business and leadership skills, majority of youth remain unemployed. This is mostly attributed to a lack of financial support to start or grow businesses, politicisation of programmes and the unstable state of the Zimbabwean economy which is not favourable for the survival and growth of small businesses. The researcher recommended increased government participation and collaboration with the private sector to promote youth businesses and tackle unemployment in a holistic manner. Promotion of economic growth and stability, depolitising empowerment programmes and strengthening monitoring and evaluation systems are also crucial to achieve real impact in youth development initiatives. Furthermore, providing financial support, will aid in starting and sustaining businesses, after training.
- Full Text:
- Date Issued: 2019
- Authors: Muradya, Thelma Irene
- Date: 2019
- Subjects: Youth in development -- Zimbabwe -- Harare , Youth -- Employment -- Zimbabwe -- Harare , Community development -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/41592 , vital:36543
- Description: The study evaluated the sustainability of the International Labour Organisation’s ‘Skills for youth employment and rural development’ programme in Harare. The purpose of the study was to understand the reasons behind the rise of youth unemployment despite many interventions targeting youth being implemented within the country. Youth contribute to the development of nations if presented with opportunities. Also, the economy of Zimbabwe is highly informal; hence the need to assess the long term impact made by strengthening the skills of the youth through informal apprenticeships and if there were possibilities of growth within their businesses. Sustainability issues were therefore critical in addressing problems faced by youth empowerment initiatives, so as to ensure that beneficiaries of programs attain long term benefits in future and that future programmes can also make sustainability their core focus. This mixed method study utilised interviews with youth beneficiaries and an ILO official in Harare as well as document analysis to gather data about the programme. The findings indicated that despite the programme achieving its targeted objectives and providing skills within the various sectors as well as business and leadership skills, majority of youth remain unemployed. This is mostly attributed to a lack of financial support to start or grow businesses, politicisation of programmes and the unstable state of the Zimbabwean economy which is not favourable for the survival and growth of small businesses. The researcher recommended increased government participation and collaboration with the private sector to promote youth businesses and tackle unemployment in a holistic manner. Promotion of economic growth and stability, depolitising empowerment programmes and strengthening monitoring and evaluation systems are also crucial to achieve real impact in youth development initiatives. Furthermore, providing financial support, will aid in starting and sustaining businesses, after training.
- Full Text:
- Date Issued: 2019
The sustainability of small, medium and micro enterprises within the Nelson Mandela Bay Metropole
- Authors: Taft, Giovanni Sinclair
- Date: 2019
- Subjects: Small business -- South Africa -- Nelson Mandela Bay Municipality , Business enterprises -- South Africa -- Nelson Mandela Bay Municipality Construction industry -- South Africa -- Nelson Mandela Bay Municipality
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/43911 , vital:37083
- Description: This research evaluates the sustainability of Small, Medium and Micro Enterprises (SMMEs) within the Nelson Mandela Bay Metropole. It seeks to identify whether the current government initiatives offered by the SEDA, DTI and CIDB are effectively addressing the major issues faced by SMMEs in order for them to remain sustainable. It seeks clarity on whether large construction companies should also take responsibility for keeping SMMEs sustainable. The challenges faced by SMMEs include limited financial resources, poor access to markets, little infrastructure, complex labour laws, rampant crime, shortage of skills and bureaucratic systems (SEDA 2016). Government has made concerted efforts to address these challenges so that affirmative action and Broad Based Black Economic Empowerment (B-BBEE) objectives are met. This led to the establishment of the SEDA, DTI and CIDB. Despite the above governments efforts, SMMEs are still failing, and the factors that contribute to this need to be identified. Not being sustainable restricts economic growth and further widens the gap between the haves and havenots. The research methodology included interviews with contractors, consultants and SMME employees. Data collected were analysed to establish patterns that emerged, and triangulation was employed to consolidate the analysis. The process was conducted against the backdrop of a literature review that explored definitions, international reviews of SMMEs, the experience of SMMEs in developing and developed nations and an evaluation of government support to SMMEs. The research confirmed that SMME employees were generally inexperienced, had a poor understanding of the construction industry and endured huge financial constraints. Appointed Professional Consultants did not include them in project planning, while large appointed Construction companies needed to acknowledge the vital role that they played in the overall state economy. Finally, recommendations are made to develop and sustain SMMEs so that they take their rightful place in the Nelson Mandela Bay Metropole.
- Full Text:
- Date Issued: 2019
- Authors: Taft, Giovanni Sinclair
- Date: 2019
- Subjects: Small business -- South Africa -- Nelson Mandela Bay Municipality , Business enterprises -- South Africa -- Nelson Mandela Bay Municipality Construction industry -- South Africa -- Nelson Mandela Bay Municipality
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/43911 , vital:37083
- Description: This research evaluates the sustainability of Small, Medium and Micro Enterprises (SMMEs) within the Nelson Mandela Bay Metropole. It seeks to identify whether the current government initiatives offered by the SEDA, DTI and CIDB are effectively addressing the major issues faced by SMMEs in order for them to remain sustainable. It seeks clarity on whether large construction companies should also take responsibility for keeping SMMEs sustainable. The challenges faced by SMMEs include limited financial resources, poor access to markets, little infrastructure, complex labour laws, rampant crime, shortage of skills and bureaucratic systems (SEDA 2016). Government has made concerted efforts to address these challenges so that affirmative action and Broad Based Black Economic Empowerment (B-BBEE) objectives are met. This led to the establishment of the SEDA, DTI and CIDB. Despite the above governments efforts, SMMEs are still failing, and the factors that contribute to this need to be identified. Not being sustainable restricts economic growth and further widens the gap between the haves and havenots. The research methodology included interviews with contractors, consultants and SMME employees. Data collected were analysed to establish patterns that emerged, and triangulation was employed to consolidate the analysis. The process was conducted against the backdrop of a literature review that explored definitions, international reviews of SMMEs, the experience of SMMEs in developing and developed nations and an evaluation of government support to SMMEs. The research confirmed that SMME employees were generally inexperienced, had a poor understanding of the construction industry and endured huge financial constraints. Appointed Professional Consultants did not include them in project planning, while large appointed Construction companies needed to acknowledge the vital role that they played in the overall state economy. Finally, recommendations are made to develop and sustain SMMEs so that they take their rightful place in the Nelson Mandela Bay Metropole.
- Full Text:
- Date Issued: 2019
The synthesis and assessment of thioxanthone- and xanthone- derived compounds as hosts for application in host-guest chemistry
- Authors: Greyling, Lizé
- Date: 2019
- Subjects: Chemistry, Organic , Biochemistry
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/42525 , vital:36665
- Description: In this work, the host capabilities of two structurally related compounds, N,N’-bis(9-phenyl-9- thioxanthenyl)ethylenediamine (H1) and N,N’-bis(9-phenyl-9-xanthenyl)ethylenediamine (H2) were compared in the presence of a wide variety of guest species. Additionally, the selectivity displayed by these host compounds were examined when exposed to mixtures of guests in order to ascertain whether it would be feasible to employ them in alternative separation strategies for the purification of industrially relevant chemicals. H1 and H2 were synthesized by reacting thioxanthone and xanthone with phenylmagnesium bromide. The resultant alcohol was then treated with perchloric acid and, finally, two of these molecules were effectively linked by utilizing ethylenediamine to afford the two host compounds. Initially, H1 and H2 were investigated for their inclusion abilities by recrystallizing each from a number of potential isomeric and non-isomeric guest compounds such as the xylenes and ethylbenzene, methylanisoles and anisole, methylpyridines and pyridine, methylcyclohexanones and cyclohexanone, heterocyclic five- and six- membered ring compounds, alkylsubstituted benzenes, anilines, and dihaloalkanes. H1 displayed excellent inclusion ability when presented with the above-mentioned compounds, and a 1:1 H:G ratio was consistently preferred in each case. H2 also proved to be successful in this regard but did not include the methylcyclohexanones and cyclohexanone nor the heterocyclic five-membered ring solvents. Furthermore, varying host:guest ratios were observed for the complexes formed with H2. Mixed competition experiments were carried out in the presence of either isomeric or related but non-isomeric guest species. When H1 and H2 were independently recrystallized from mixtures of the former, selectivity orders correlated for both hosts, but it was observed that H2 exhibited an enhanced selectivity for the preferred guests in each case, compared with H1. Interestingly, in mixtures of the latter, host behaviours were distinctly opposing (with the exception of the dihaloalkanes). H1, and even more so H2, demonstrated very high selectivities for p-xylene, aniline and N,Ndimethylaniline from the xylene and aniline guest series, respectively, where selectivities were found to be ~90% or higher for host recrystallization experiments from respective mixtures of these guests. Single crystal X-ray diffraction, Hirshfeld surface and thermal analyses were employed in order to elucidate the reasons for any selectivity observations. The inclusion of these guests was, in most cases, found to be as a result of interactions between host and guest species, which included π∙∙∙π stacking, C‒H∙∙∙π, hydrogen bonding and various other short contact types. Guest compounds were accommodated in either cavities or channels and this was dependent on the nature of the guest. The host molecule conformations showed H1 to adopt a bent tricyclic fused ring system with the N atoms of the linker in a synclinal arrangement, while in complexes with H2, the fused ring system was near-planar and the N atoms adopted an antiperiplanar geometry. These key differences resulted in a very ordered host‒host packing for H2 as a direct result of the more planar O-containing ring and linear linker; for H1, on the other hand, the buckled S-containing ring and gauche-orientated N atoms resulted in a less ordered packing, which ultimately related to the differences in the behaviour of the two host species. Hirshfeld surface analyses, in general, did not provide much information to explain the host selectivities, with the exception of complexes containing the five-membered ring guest heterocyclics. Thermal analyses were completed on all suitable host-guest complexes and, in most cases but not all, the onset and peak temperatures (terms Ton and Tp, respectively) were related to the thermal stability of the complexes, which were used to rationalize the selectivities of these host compounds.
- Full Text:
- Date Issued: 2019
- Authors: Greyling, Lizé
- Date: 2019
- Subjects: Chemistry, Organic , Biochemistry
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/42525 , vital:36665
- Description: In this work, the host capabilities of two structurally related compounds, N,N’-bis(9-phenyl-9- thioxanthenyl)ethylenediamine (H1) and N,N’-bis(9-phenyl-9-xanthenyl)ethylenediamine (H2) were compared in the presence of a wide variety of guest species. Additionally, the selectivity displayed by these host compounds were examined when exposed to mixtures of guests in order to ascertain whether it would be feasible to employ them in alternative separation strategies for the purification of industrially relevant chemicals. H1 and H2 were synthesized by reacting thioxanthone and xanthone with phenylmagnesium bromide. The resultant alcohol was then treated with perchloric acid and, finally, two of these molecules were effectively linked by utilizing ethylenediamine to afford the two host compounds. Initially, H1 and H2 were investigated for their inclusion abilities by recrystallizing each from a number of potential isomeric and non-isomeric guest compounds such as the xylenes and ethylbenzene, methylanisoles and anisole, methylpyridines and pyridine, methylcyclohexanones and cyclohexanone, heterocyclic five- and six- membered ring compounds, alkylsubstituted benzenes, anilines, and dihaloalkanes. H1 displayed excellent inclusion ability when presented with the above-mentioned compounds, and a 1:1 H:G ratio was consistently preferred in each case. H2 also proved to be successful in this regard but did not include the methylcyclohexanones and cyclohexanone nor the heterocyclic five-membered ring solvents. Furthermore, varying host:guest ratios were observed for the complexes formed with H2. Mixed competition experiments were carried out in the presence of either isomeric or related but non-isomeric guest species. When H1 and H2 were independently recrystallized from mixtures of the former, selectivity orders correlated for both hosts, but it was observed that H2 exhibited an enhanced selectivity for the preferred guests in each case, compared with H1. Interestingly, in mixtures of the latter, host behaviours were distinctly opposing (with the exception of the dihaloalkanes). H1, and even more so H2, demonstrated very high selectivities for p-xylene, aniline and N,Ndimethylaniline from the xylene and aniline guest series, respectively, where selectivities were found to be ~90% or higher for host recrystallization experiments from respective mixtures of these guests. Single crystal X-ray diffraction, Hirshfeld surface and thermal analyses were employed in order to elucidate the reasons for any selectivity observations. The inclusion of these guests was, in most cases, found to be as a result of interactions between host and guest species, which included π∙∙∙π stacking, C‒H∙∙∙π, hydrogen bonding and various other short contact types. Guest compounds were accommodated in either cavities or channels and this was dependent on the nature of the guest. The host molecule conformations showed H1 to adopt a bent tricyclic fused ring system with the N atoms of the linker in a synclinal arrangement, while in complexes with H2, the fused ring system was near-planar and the N atoms adopted an antiperiplanar geometry. These key differences resulted in a very ordered host‒host packing for H2 as a direct result of the more planar O-containing ring and linear linker; for H1, on the other hand, the buckled S-containing ring and gauche-orientated N atoms resulted in a less ordered packing, which ultimately related to the differences in the behaviour of the two host species. Hirshfeld surface analyses, in general, did not provide much information to explain the host selectivities, with the exception of complexes containing the five-membered ring guest heterocyclics. Thermal analyses were completed on all suitable host-guest complexes and, in most cases but not all, the onset and peak temperatures (terms Ton and Tp, respectively) were related to the thermal stability of the complexes, which were used to rationalize the selectivities of these host compounds.
- Full Text:
- Date Issued: 2019
The synthesis, characterization, and application of peptide-capped magnetite nanoparticles for the targeting of cancer cells
- Authors: Hickson, Matthew Victor
- Date: 2019
- Subjects: Nanomedicine -- Research , Nanostructured materials Cancer -- Alternative treatment
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/40172 , vital:35965
- Description: In this study, a comparative analysis was performed upon three co-precipitation techniques for the synthesis of capped magnetite nanoparticles as to optimize the approach to the highest quality nanoparticles. Three techniques were applied whereby the capping agent either introduced before the stage of nanoparticle precipitation, simultaneously to the stage of precipitation, or after the stage of precipitation. The resultant nanoparticles were tested in terms of their size, dispersity, crystallinity, and magnetic characteristics. The three techniques gave nanoparticles of varying sizes and characteristics. Out of the three synthetic techniques, the post precipitation introduction method gave the highest quality nanoparticles in terms of size distribution, crystallinity and magnetic character. Three novel peptides were synthesized, incorporating amino acids to varying degrees. Structure was confirmed via IR and NMR spectroscopy. The peptides were studied potentiometrically to explore their acid nature and were explored computationally as to discern possible modes of interaction with the nanoparticles. These three peptides were further used in the capping of magnetite nanoparticles. For this set of nanoparticles, a higher synthesis temperature and larger iron content were used as to obtain larger nanoparticles. For the capping procedure, the post precipitation technique was used due to its previous positive results, once again yielding high quality nanoparticles with low size dispersity, high crystallinity, and high magnetic saturations. The nanoparticles were also seen to display positive zeta potentials, which are beneficial for cellular interactions. The peptides and peptide-capped nanoparticles were tested for biological activity against the healthy MCF-10A and cancerous MCF-7 cell lines. The MTT assay displayed increased proliferation for both the cell lines treated with the nanoparticles, while the peptide treatments decreased the MCF-10A cell lines proliferation and increased the MCF-7 proliferation. TEM analysis displayed nanoparticles in the cellular sections. An ICP-OES analysis on the cells showed that the capped nanoparticles of similar zeta potentials were seen to be taken up excessively by cells as compared to the uncapped. The nanoparticles of lower zeta potentials but higher L-glutamine content were taken up to a lesser degree.
- Full Text:
- Date Issued: 2019
- Authors: Hickson, Matthew Victor
- Date: 2019
- Subjects: Nanomedicine -- Research , Nanostructured materials Cancer -- Alternative treatment
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/40172 , vital:35965
- Description: In this study, a comparative analysis was performed upon three co-precipitation techniques for the synthesis of capped magnetite nanoparticles as to optimize the approach to the highest quality nanoparticles. Three techniques were applied whereby the capping agent either introduced before the stage of nanoparticle precipitation, simultaneously to the stage of precipitation, or after the stage of precipitation. The resultant nanoparticles were tested in terms of their size, dispersity, crystallinity, and magnetic characteristics. The three techniques gave nanoparticles of varying sizes and characteristics. Out of the three synthetic techniques, the post precipitation introduction method gave the highest quality nanoparticles in terms of size distribution, crystallinity and magnetic character. Three novel peptides were synthesized, incorporating amino acids to varying degrees. Structure was confirmed via IR and NMR spectroscopy. The peptides were studied potentiometrically to explore their acid nature and were explored computationally as to discern possible modes of interaction with the nanoparticles. These three peptides were further used in the capping of magnetite nanoparticles. For this set of nanoparticles, a higher synthesis temperature and larger iron content were used as to obtain larger nanoparticles. For the capping procedure, the post precipitation technique was used due to its previous positive results, once again yielding high quality nanoparticles with low size dispersity, high crystallinity, and high magnetic saturations. The nanoparticles were also seen to display positive zeta potentials, which are beneficial for cellular interactions. The peptides and peptide-capped nanoparticles were tested for biological activity against the healthy MCF-10A and cancerous MCF-7 cell lines. The MTT assay displayed increased proliferation for both the cell lines treated with the nanoparticles, while the peptide treatments decreased the MCF-10A cell lines proliferation and increased the MCF-7 proliferation. TEM analysis displayed nanoparticles in the cellular sections. An ICP-OES analysis on the cells showed that the capped nanoparticles of similar zeta potentials were seen to be taken up excessively by cells as compared to the uncapped. The nanoparticles of lower zeta potentials but higher L-glutamine content were taken up to a lesser degree.
- Full Text:
- Date Issued: 2019
The taxation of the “sharing economy” in South Africa
- Authors: Gumbo, Wadzanai Charisma
- Date: 2019
- Subjects: Corporations -- Taxation Taxation -- South Africa Value-added tax -- Law and legislation -- South Africa Double taxation -- South Africa Tax evasion -- South Africa Income tax -- Law and legislation -- South Africa Tax administration and procedure -- South Africa
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/64045 , vital:28525
- Description: The research examined whether the services provided by the “sharing economy” platforms are adequately dealt with by the current South African tax systems. In addressing this main goal, the research analysed how the South African tax systems deal with the income and expenses of Uber, Airbnb and their respective service providers. The research also investigated how South Africa could classify “sharing economy” workers and how this would affect the deductibility of the worker’s expenses. A brief analysis was made of the taxation of the “sharing economy” businesses in Australia and the United States of America. These countries have implemented measures to effectively deal with regulating the “sharing economy” businesses. An interpretative research approach was used to provide clarity on the matter. Documentary data used for the research consists of tax legislation, case law, textbooks, commentaries, journal articles and theses. The research concluded that the current taxation systems have loopholes that are allowing participants in the “sharing economy” to avoid paying tax in South Africa. The thesis recommends that the legislature could adopt certain measures applied in Australia and the United States of America to more effectively regulate “sharing economy” in South African and remedy the leakages the current tax systems suffer, causing SARS to lose potential revenue.
- Full Text:
- Date Issued: 2019
- Authors: Gumbo, Wadzanai Charisma
- Date: 2019
- Subjects: Corporations -- Taxation Taxation -- South Africa Value-added tax -- Law and legislation -- South Africa Double taxation -- South Africa Tax evasion -- South Africa Income tax -- Law and legislation -- South Africa Tax administration and procedure -- South Africa
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/64045 , vital:28525
- Description: The research examined whether the services provided by the “sharing economy” platforms are adequately dealt with by the current South African tax systems. In addressing this main goal, the research analysed how the South African tax systems deal with the income and expenses of Uber, Airbnb and their respective service providers. The research also investigated how South Africa could classify “sharing economy” workers and how this would affect the deductibility of the worker’s expenses. A brief analysis was made of the taxation of the “sharing economy” businesses in Australia and the United States of America. These countries have implemented measures to effectively deal with regulating the “sharing economy” businesses. An interpretative research approach was used to provide clarity on the matter. Documentary data used for the research consists of tax legislation, case law, textbooks, commentaries, journal articles and theses. The research concluded that the current taxation systems have loopholes that are allowing participants in the “sharing economy” to avoid paying tax in South Africa. The thesis recommends that the legislature could adopt certain measures applied in Australia and the United States of America to more effectively regulate “sharing economy” in South African and remedy the leakages the current tax systems suffer, causing SARS to lose potential revenue.
- Full Text:
- Date Issued: 2019
The tertiary education institution of the future towards 2030: scenarios for skills transformation
- Authors: Chikoti, Patrick
- Date: 2019
- Subjects: Education, Higher -- South Africa , Universities and colleges -- Administration Education, Higher -- Aims and objectives -- South Africa Education, Higher -- Economic aspects -- South Africa Educational change -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/37958 , vital:34274
- Description: The research methodology used in this research was comprised of Inayatullah’s Six Pillars of Futures Studies, in which emphasis was placed on scenario planning and the creation of alternative scenarios for the tertiary education institutions in South Africa towards 2030. An environmental scan revealed the drivers of change in the education sector and in the world of work. Deepening of the future of education was done through Causal Layered Analysis (CLA) to facilitate the discerning of issues from various viewpoints in the creation and expansion of transformative stories so as to provide a window into possible futures for skills transformation. The four scenarios for the tertiary education institution of the future, namely “Stairway to Heaven”, “Highway to Hell”, “Bat out of Hell” and “Still Raining” were developed. These scenarios can be used as departure points by tertiary education providers to make strides towards the Global Sustainable Development Education 2030 targets and the attainment of South Africa’s Vision 2030 targets contained in the National Development Plan. Equally important, these scenarios make known what was previously unknown, exploring the possible and impossible, and encouraging new, innovative thinking for decision-makers. The “Stairway to Heaven” scenario supplies a future in which all stakeholders approve of and embrace the mandate of providing relevant skills and job readiness in a fast-changing world, and the benefits are maximised for all involved through co-creation. It is a scenario where industry, tertiary institutions and society have decided that the purpose of education should be lifelong learning for a viable, productive and sustainable world. The desired future of tertiary education is set against a backdrop of public and private sector collaboration, with the aim of turning the nation into an excellent hub for skills transformation. Furthermore, the scenario provides some insight on the vital measures required to embrace the innovation and the appropriate pedagogy. This research was motivated by the need to shine a light on the 21st century learner, rapidly obsoleting skills, no-collar worker, skills of the future, learning futures, and possible predictions about what new jobs may come into existence so that educationists can better prepare for the future. This research offers solutions on how institutions can prepare students for future jobs, especially considering the rapid changes in jobs and the unprecedented demise of certain jobs. The research closes a research gap through creating scenarios that offer various stakeholders in the tertiary education sector different insights and analysis into a number of interpretations of the potential paths that they can follow. The scenario application culminated in the formulation and creation of a “future vision of the tertiary education institution in South Africa towards 2030”, delivering a platform for skills transformation that will deliver adaptable workers, and sustainable and inclusive progress for all South Africans. To bring transformation into the present and design the future that embraces skills transformation, it is invaluable to interrogate the roles and choices that stakeholders of the educational sector make in determining the preferred future. The approach of this research makes it clear that, as the new world of work transpires, policymakers, students, labour, educational leaders, captains of industry and workers must proactively manage the workforce transitions. The focal issue is to discover the appropriate tools that will establish the confidence necessary to create the preferred future for skills transformation in tertiary institutions. This research has laid a platform for co-creation with various stakeholders in an effort to visualise a tertiary institution that contributes to skills development. The vision must accept that the South African jobs and skills historical profile is different from that of industrialised countries. Alternatively, the nation should respond to the double-barrelled challenge of participating in a high skills’ competitive environment on a global scale, as well as a local context that creates low-wage, blue-collar jobs to absorb the large numbers who are unemployed. The challenge is even greater for South Africa, because the economy – if highly service-oriented, with a big informal sector and a quality postgraduate education offering – is supported by a basic education system that is not producing enough critical thinkers who are equipped for university and work life. Thus, the system requires a double transformation to ensure student-centredness and meet the needs of a future worker.
- Full Text:
- Date Issued: 2019
- Authors: Chikoti, Patrick
- Date: 2019
- Subjects: Education, Higher -- South Africa , Universities and colleges -- Administration Education, Higher -- Aims and objectives -- South Africa Education, Higher -- Economic aspects -- South Africa Educational change -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/37958 , vital:34274
- Description: The research methodology used in this research was comprised of Inayatullah’s Six Pillars of Futures Studies, in which emphasis was placed on scenario planning and the creation of alternative scenarios for the tertiary education institutions in South Africa towards 2030. An environmental scan revealed the drivers of change in the education sector and in the world of work. Deepening of the future of education was done through Causal Layered Analysis (CLA) to facilitate the discerning of issues from various viewpoints in the creation and expansion of transformative stories so as to provide a window into possible futures for skills transformation. The four scenarios for the tertiary education institution of the future, namely “Stairway to Heaven”, “Highway to Hell”, “Bat out of Hell” and “Still Raining” were developed. These scenarios can be used as departure points by tertiary education providers to make strides towards the Global Sustainable Development Education 2030 targets and the attainment of South Africa’s Vision 2030 targets contained in the National Development Plan. Equally important, these scenarios make known what was previously unknown, exploring the possible and impossible, and encouraging new, innovative thinking for decision-makers. The “Stairway to Heaven” scenario supplies a future in which all stakeholders approve of and embrace the mandate of providing relevant skills and job readiness in a fast-changing world, and the benefits are maximised for all involved through co-creation. It is a scenario where industry, tertiary institutions and society have decided that the purpose of education should be lifelong learning for a viable, productive and sustainable world. The desired future of tertiary education is set against a backdrop of public and private sector collaboration, with the aim of turning the nation into an excellent hub for skills transformation. Furthermore, the scenario provides some insight on the vital measures required to embrace the innovation and the appropriate pedagogy. This research was motivated by the need to shine a light on the 21st century learner, rapidly obsoleting skills, no-collar worker, skills of the future, learning futures, and possible predictions about what new jobs may come into existence so that educationists can better prepare for the future. This research offers solutions on how institutions can prepare students for future jobs, especially considering the rapid changes in jobs and the unprecedented demise of certain jobs. The research closes a research gap through creating scenarios that offer various stakeholders in the tertiary education sector different insights and analysis into a number of interpretations of the potential paths that they can follow. The scenario application culminated in the formulation and creation of a “future vision of the tertiary education institution in South Africa towards 2030”, delivering a platform for skills transformation that will deliver adaptable workers, and sustainable and inclusive progress for all South Africans. To bring transformation into the present and design the future that embraces skills transformation, it is invaluable to interrogate the roles and choices that stakeholders of the educational sector make in determining the preferred future. The approach of this research makes it clear that, as the new world of work transpires, policymakers, students, labour, educational leaders, captains of industry and workers must proactively manage the workforce transitions. The focal issue is to discover the appropriate tools that will establish the confidence necessary to create the preferred future for skills transformation in tertiary institutions. This research has laid a platform for co-creation with various stakeholders in an effort to visualise a tertiary institution that contributes to skills development. The vision must accept that the South African jobs and skills historical profile is different from that of industrialised countries. Alternatively, the nation should respond to the double-barrelled challenge of participating in a high skills’ competitive environment on a global scale, as well as a local context that creates low-wage, blue-collar jobs to absorb the large numbers who are unemployed. The challenge is even greater for South Africa, because the economy – if highly service-oriented, with a big informal sector and a quality postgraduate education offering – is supported by a basic education system that is not producing enough critical thinkers who are equipped for university and work life. Thus, the system requires a double transformation to ensure student-centredness and meet the needs of a future worker.
- Full Text:
- Date Issued: 2019
The testing of natural and synthetic adjuvants to reduce herbicide-use and/or improve efficacy for the control of difficult-to-kill forest weeds
- Authors: Letaoana, Josias Tshukudu
- Date: 2019
- Subjects: Weeds -- Control , Invasive plants -- South Africa Invasive plants -- Ecology -- South Africa Forest ecology -- South Africa Forests and forestry -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/40371 , vital:36153
- Description: Commercial plantations within South Africa occur across diverse sites in terms of climate and physiography. Intensive silvicultural practices (site preparation, fertilisation, weed management etc.) are carried out during the establishment phase to ensure that the actual production of timber approximates the potential capacity for a site. Of these silvicultural practices, weed management is regarded as one of the most important, as if not carried out, competition from weeds may negatively influence seedling survival, growth and uniformity. During the establishment phase (planting to canopy closure), weed management operations are generally effective, as most competing species are still in a juvenile growth phase, and easily controlled. Due to limited weed-tree competition following canopy closure, weed management operations are reduced to a single event per annum (if necessary). This reduction in weed management often allows semi-shade/shade tolerant species to become established, together with an increase in the effort required for their control. The South African forest industry makes use of independent international auditing bodies to ensure that plantations are managed in a responsible, yet sustainable manner. Integrated management practices are considered the most effective as they reduce reliance on a single control method, such as the use of herbicides alone. In conjunction with integrated management, would be the need to reduce the overall quantities of herbicides used, yet at the same time ensuring improved efficacy of those herbicides that are used. The testing of these two aspects (reduced herbicide use and/or improved efficacy) was conducted on three diverse weeds that occur during the post-establishment phase within South African plantations, namely: Setaria megaphylla (setaria); Hedychium gardnerianum (wild ginger); and Solanum mauritianum (bugweed). The management of these species is considered problematic, as current herbicides and rates of application are not always completely effective. Four trials were implemented in KwaZulu-Natal (Midlands). Setaria megaphylla (setaria): Two trials were initiated (spring and autumn), to test the seasonal application of glyphosate + adjuvant combinations for improved efficacy (and hence reduced herbicide-use). A control (no herbicide applied), Select® (clethodim cyclohexanedione 120 g a.i. ℓ-1), Roundup® (glyphosate isopropylamine salt 360 g a.i. ℓ-1), and five Roundup® + adjuvant combinations were tested in both trials. iii The five adjuvants included three natural and two synthetic products that exhibited different properties and modes of action. At both sites, the eight treatments were replicated three times and laid out in a randomised complete blocks design. Setaria cover was assessed prior to spraying (0 days relative to spraying), and then again after two months (64 days relative spraying), with absolute changes in regrowth analysed. Although the application of Roundup® on its own provided good control within both trials, complete setaria control could not be obtained. Select® and the tested adjuvants did not improve Roundup® efficacy at the rates at which they were applied. The application of Roundup® in autumn (x̄ = 5.2% live cover) was more effective than the spring application (x̄ = 8.5% live cover), indicating that future studies should focus more on a combination of a season of application and subsequent follow-up operations, rather than the role of the adjuvants tested. Hedychium gardnerianum (wild ginger): Currently no herbicides are registered for the control of wild ginger in South Africa. One trial was implemented to test the potential for the control of wild ginger with herbicides applied to the foliage, cut-stems or rhizomes. In addition to an untreated control (no herbicide applied), Roundup® (glyphosate isopropylamine salt 360 g a.i. ℓ-1 at 4%) was applied as a foliar spray, either alone or with five adjuvants (three natural and two synthetic adjuvants). Brush- Off® (metsulfuron-methyl 6 g a.i. ℓ-1) or Roundup® was also applied to the cut-stems and rhizomes. Herbicide phytotoxicity was assessed up till 229 days after treatment application in terms of mortality, reduced and/or abnormal growth (of the resprouts) and foliar necrosis and/or discolouration. Although the foliar application of Roundup® (alone or with adjuvants) resulted in limited phytotoxicity, these treatments were ineffective in terms of killing wild ginger. The application of Roundup® or Brush-Off® to either the cut rhizome or cut-stems were equally effective, however, the cut-stem application would be preferred due to the reduced effort required. Future studies should further optimize the application of Roundup® (lowered rates + adjuvants) to the cut-stems/rhizome. Solanum mauritianum (bugweed): One trial was implemented on a stand of mature bugweed (located within a pine stand). The potential to reduce rates and/or improve the efficacy of Garlon® (triclopyr butoxyethyl ester 480 g a.i. ℓ-1®) was tested through the use of four adjuvants (two natural and two synthetic products) when applied as either a cut-surface or basal bark application. Two untreated controls (cut-surface or iv basal bark) were included for comparative purposes. The trial consisted of a 2 x 5 factorial arrangement of 10 treatments replicated three times and laid out as a randomized complete block design (RCBD). Although the cut-surface treatments were more effective than the basal bark treatments, no treatment provided complete control of bugweed. Of the cut-surface treatments, Garlon® + Break-Thru® (polyether-polymethylsiloxane-copolymer 1 000 g ℓ-1), Garlon® + Orosorb® (orange oil 50 g ℓ-1), and Garlon® + Actipron Super® (mineral oil 820 g ℓ-1) were equally effective, with Garlon® + Nu-Film P® (poly-1-menthene 975 g ℓ-1) the least effective. As the adjuvants tested did not improve the efficacy of Garlon® at the rates applied, the use of the most cost-effective and environmentally acceptable product would be preferable. For effective long-term control of mature bugweed, a cutsurface application is advisable, together with follow-up operations required. The results from these trials indicate that for bugweed and setaria, the currently registered herbicides remain the products of choice, albeit not 100% effective on wellestablished plants. In addition, the use of the adjuvants tested did not improve herbicide efficacy (and hence the opportunity for reducing rates of application) for all three species tested. However, Roundup® or Brush-Off® applied to either the cut rhizome or cut-stems were equally effective in terms of wild ginger control, indicating an opportunity for further testing to optimise rates of application.
- Full Text:
- Date Issued: 2019
- Authors: Letaoana, Josias Tshukudu
- Date: 2019
- Subjects: Weeds -- Control , Invasive plants -- South Africa Invasive plants -- Ecology -- South Africa Forest ecology -- South Africa Forests and forestry -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/40371 , vital:36153
- Description: Commercial plantations within South Africa occur across diverse sites in terms of climate and physiography. Intensive silvicultural practices (site preparation, fertilisation, weed management etc.) are carried out during the establishment phase to ensure that the actual production of timber approximates the potential capacity for a site. Of these silvicultural practices, weed management is regarded as one of the most important, as if not carried out, competition from weeds may negatively influence seedling survival, growth and uniformity. During the establishment phase (planting to canopy closure), weed management operations are generally effective, as most competing species are still in a juvenile growth phase, and easily controlled. Due to limited weed-tree competition following canopy closure, weed management operations are reduced to a single event per annum (if necessary). This reduction in weed management often allows semi-shade/shade tolerant species to become established, together with an increase in the effort required for their control. The South African forest industry makes use of independent international auditing bodies to ensure that plantations are managed in a responsible, yet sustainable manner. Integrated management practices are considered the most effective as they reduce reliance on a single control method, such as the use of herbicides alone. In conjunction with integrated management, would be the need to reduce the overall quantities of herbicides used, yet at the same time ensuring improved efficacy of those herbicides that are used. The testing of these two aspects (reduced herbicide use and/or improved efficacy) was conducted on three diverse weeds that occur during the post-establishment phase within South African plantations, namely: Setaria megaphylla (setaria); Hedychium gardnerianum (wild ginger); and Solanum mauritianum (bugweed). The management of these species is considered problematic, as current herbicides and rates of application are not always completely effective. Four trials were implemented in KwaZulu-Natal (Midlands). Setaria megaphylla (setaria): Two trials were initiated (spring and autumn), to test the seasonal application of glyphosate + adjuvant combinations for improved efficacy (and hence reduced herbicide-use). A control (no herbicide applied), Select® (clethodim cyclohexanedione 120 g a.i. ℓ-1), Roundup® (glyphosate isopropylamine salt 360 g a.i. ℓ-1), and five Roundup® + adjuvant combinations were tested in both trials. iii The five adjuvants included three natural and two synthetic products that exhibited different properties and modes of action. At both sites, the eight treatments were replicated three times and laid out in a randomised complete blocks design. Setaria cover was assessed prior to spraying (0 days relative to spraying), and then again after two months (64 days relative spraying), with absolute changes in regrowth analysed. Although the application of Roundup® on its own provided good control within both trials, complete setaria control could not be obtained. Select® and the tested adjuvants did not improve Roundup® efficacy at the rates at which they were applied. The application of Roundup® in autumn (x̄ = 5.2% live cover) was more effective than the spring application (x̄ = 8.5% live cover), indicating that future studies should focus more on a combination of a season of application and subsequent follow-up operations, rather than the role of the adjuvants tested. Hedychium gardnerianum (wild ginger): Currently no herbicides are registered for the control of wild ginger in South Africa. One trial was implemented to test the potential for the control of wild ginger with herbicides applied to the foliage, cut-stems or rhizomes. In addition to an untreated control (no herbicide applied), Roundup® (glyphosate isopropylamine salt 360 g a.i. ℓ-1 at 4%) was applied as a foliar spray, either alone or with five adjuvants (three natural and two synthetic adjuvants). Brush- Off® (metsulfuron-methyl 6 g a.i. ℓ-1) or Roundup® was also applied to the cut-stems and rhizomes. Herbicide phytotoxicity was assessed up till 229 days after treatment application in terms of mortality, reduced and/or abnormal growth (of the resprouts) and foliar necrosis and/or discolouration. Although the foliar application of Roundup® (alone or with adjuvants) resulted in limited phytotoxicity, these treatments were ineffective in terms of killing wild ginger. The application of Roundup® or Brush-Off® to either the cut rhizome or cut-stems were equally effective, however, the cut-stem application would be preferred due to the reduced effort required. Future studies should further optimize the application of Roundup® (lowered rates + adjuvants) to the cut-stems/rhizome. Solanum mauritianum (bugweed): One trial was implemented on a stand of mature bugweed (located within a pine stand). The potential to reduce rates and/or improve the efficacy of Garlon® (triclopyr butoxyethyl ester 480 g a.i. ℓ-1®) was tested through the use of four adjuvants (two natural and two synthetic products) when applied as either a cut-surface or basal bark application. Two untreated controls (cut-surface or iv basal bark) were included for comparative purposes. The trial consisted of a 2 x 5 factorial arrangement of 10 treatments replicated three times and laid out as a randomized complete block design (RCBD). Although the cut-surface treatments were more effective than the basal bark treatments, no treatment provided complete control of bugweed. Of the cut-surface treatments, Garlon® + Break-Thru® (polyether-polymethylsiloxane-copolymer 1 000 g ℓ-1), Garlon® + Orosorb® (orange oil 50 g ℓ-1), and Garlon® + Actipron Super® (mineral oil 820 g ℓ-1) were equally effective, with Garlon® + Nu-Film P® (poly-1-menthene 975 g ℓ-1) the least effective. As the adjuvants tested did not improve the efficacy of Garlon® at the rates applied, the use of the most cost-effective and environmentally acceptable product would be preferable. For effective long-term control of mature bugweed, a cutsurface application is advisable, together with follow-up operations required. The results from these trials indicate that for bugweed and setaria, the currently registered herbicides remain the products of choice, albeit not 100% effective on wellestablished plants. In addition, the use of the adjuvants tested did not improve herbicide efficacy (and hence the opportunity for reducing rates of application) for all three species tested. However, Roundup® or Brush-Off® applied to either the cut rhizome or cut-stems were equally effective in terms of wild ginger control, indicating an opportunity for further testing to optimise rates of application.
- Full Text:
- Date Issued: 2019
The thermal physiology of Stenopelmus rufinasus and Neohydronomus affinis (Coleoptera: Curculionidae), two biological control agents for the invasive alien aquatic weeds, Azolla filiculoides and Pistia stratiotes in South Africa.
- Mvandaba, Sisanda F, Owen, Candice A, Hill, Martin P, Coetzee, Julie A
- Authors: Mvandaba, Sisanda F , Owen, Candice A , Hill, Martin P , Coetzee, Julie A
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444467 , vital:74243 , https://doi.org/10.1080/09583157.2018.1525484
- Description: Water lettuce, Pistia stratiotes, and red water fern, Azolla filiculoides, are floating aquatic macrophytes that have become problematic in South Africa. Two weevils, Neohydronomus affinis and Stenopelmus rufinasus, are successful biological control agents of these two species in South Africa. The aim of this study was to investigate the thermal requirements of these two species to explain their establishment patterns in the field. Laboratory results showed that both weevils are widely tolerant to cold and warm temperatures.
- Full Text:
- Date Issued: 2019
- Authors: Mvandaba, Sisanda F , Owen, Candice A , Hill, Martin P , Coetzee, Julie A
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444467 , vital:74243 , https://doi.org/10.1080/09583157.2018.1525484
- Description: Water lettuce, Pistia stratiotes, and red water fern, Azolla filiculoides, are floating aquatic macrophytes that have become problematic in South Africa. Two weevils, Neohydronomus affinis and Stenopelmus rufinasus, are successful biological control agents of these two species in South Africa. The aim of this study was to investigate the thermal requirements of these two species to explain their establishment patterns in the field. Laboratory results showed that both weevils are widely tolerant to cold and warm temperatures.
- Full Text:
- Date Issued: 2019
The time course changes in selected fatigue indicators in moderately trained participants
- Authors: Maduna, Bongani Cyprian
- Date: 2019
- Subjects: Athletes -- Health and hygiene , Fatigue , Athletes -- Physiology
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/76354 , vital:30553
- Description: Background: During daily physical activities, individuals will encounter some level of fatigue. This is especially true for athletes who exert their bodies to achieve superior performance and attempt to delay the onset of fatigue as far as possible. However, fatigue is a progressive process that is part of physical exercise. It is therefore, important to understand the various factors associated with fatigue. Objective: The purpose of this research project was to observe the changes in perceptual, physiological responses, and workload while participants performed a fatiguing cycling exercise task. In order to observe the aforementioned changes, one of the three variables, either perceptual, physiological responses or workload was kept constant, while the other two were observed as dependent variables. There were three test conditions, which permitted each variable to be kept constant in at least one of the three test conditions. Methods: Thirty-six apparently healthy university students were recruited for the study. The exercise was of 35 minute duration for each condition, with the data collection for HR (physiological response), RPE (perceptual response), and power output (workload) occurring at two minute intervals from the eighth minute until the thirtieth minute. The participants were required to perform a peak-power-output test in order set the relative performance ranges for each participant in order to elicit an observable fatigue response from all the participants. The three conditions included constant HR response, constant workload, and constant RPE response where each participant performed all of the above conditions on separate days.Results: The perceptual (RPE) response increased significantly (p<0.05) over time in all three test conditions, even under the constant RPE condition where it was expected to remain unchanged throughout the test duration. The HR response only demonstrated a significant (p<0.05) increase over time under the constant workload condition. Lastly, workload remained constant in all three testing conditions. Conclusion: Participants may be able to exercise for longer periods during sub-maximal exercise if they disregard the RPE warning response. In the current study, the RPE response illustrated that participants were being exerted more over time; however, the participants still had physiological and workload capacity to continue exercising. This research project has confirmed the fact that fatigue is a multifaceted phenomenon. Furthermore, it has been illustrated that RPE response alone as an indicator of fatigue onset may be misleading as participants did not breach the HR and workload steady state during the current research. Therefore, it may be more appropriate to assess fatigue onset through the assessment of more than one fatigue variable in order to ensure increased accuracy of the participants’ fatigue state assessment.
- Full Text:
- Date Issued: 2019
- Authors: Maduna, Bongani Cyprian
- Date: 2019
- Subjects: Athletes -- Health and hygiene , Fatigue , Athletes -- Physiology
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/76354 , vital:30553
- Description: Background: During daily physical activities, individuals will encounter some level of fatigue. This is especially true for athletes who exert their bodies to achieve superior performance and attempt to delay the onset of fatigue as far as possible. However, fatigue is a progressive process that is part of physical exercise. It is therefore, important to understand the various factors associated with fatigue. Objective: The purpose of this research project was to observe the changes in perceptual, physiological responses, and workload while participants performed a fatiguing cycling exercise task. In order to observe the aforementioned changes, one of the three variables, either perceptual, physiological responses or workload was kept constant, while the other two were observed as dependent variables. There were three test conditions, which permitted each variable to be kept constant in at least one of the three test conditions. Methods: Thirty-six apparently healthy university students were recruited for the study. The exercise was of 35 minute duration for each condition, with the data collection for HR (physiological response), RPE (perceptual response), and power output (workload) occurring at two minute intervals from the eighth minute until the thirtieth minute. The participants were required to perform a peak-power-output test in order set the relative performance ranges for each participant in order to elicit an observable fatigue response from all the participants. The three conditions included constant HR response, constant workload, and constant RPE response where each participant performed all of the above conditions on separate days.Results: The perceptual (RPE) response increased significantly (p<0.05) over time in all three test conditions, even under the constant RPE condition where it was expected to remain unchanged throughout the test duration. The HR response only demonstrated a significant (p<0.05) increase over time under the constant workload condition. Lastly, workload remained constant in all three testing conditions. Conclusion: Participants may be able to exercise for longer periods during sub-maximal exercise if they disregard the RPE warning response. In the current study, the RPE response illustrated that participants were being exerted more over time; however, the participants still had physiological and workload capacity to continue exercising. This research project has confirmed the fact that fatigue is a multifaceted phenomenon. Furthermore, it has been illustrated that RPE response alone as an indicator of fatigue onset may be misleading as participants did not breach the HR and workload steady state during the current research. Therefore, it may be more appropriate to assess fatigue onset through the assessment of more than one fatigue variable in order to ensure increased accuracy of the participants’ fatigue state assessment.
- Full Text:
- Date Issued: 2019
The translation and adaptation of Alice’s Adventures in Wonderland into isiNdebele
- Authors: Nkomo, Dion
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/469470 , vital:77245 , https://doi.org/10.2989/16073614.2019.1617175
- Description: This article reflects on the translation of Lewis Carroll’s Alice’s Adventures in Wonderland into the isiNdebele language of Zimbabwe. The isiNdebele translation, Insumansumane zika-Alice, is one of the numerous translations produced towards the 150th commemorative exhibition of Carroll’s legacy following the publication of Wonderland in 1865. The translations resulted in Wonderland becoming one of the most translated English novels, thereby vindicating the ‘universal-child hypothesis’ propounded by Warren Weaver in an earlier appraisal of Wonderland translations fifty years earlier. Weaver regarded the translation of Wonderland as a measure of the popularity of the text among children, who are arguably fascinated by Alice, with whom they are assumed to identify. This article problematises this argument in the light of most translations being initiated by non-mother-tongue speakers of target languages. It is argued that Alice’s worldwide appeal should not be taken for granted as a universal one, partly because of her particular identity, which is different from the diverse target readers. Therefore, the question of whether Alice can really become African reflects on the domestication approach that was adopted by the isiNdebele translator, among others. Special attention is paid to proper nouns and other complex features characterising Carroll’s language usage.
- Full Text:
- Date Issued: 2019
- Authors: Nkomo, Dion
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/469470 , vital:77245 , https://doi.org/10.2989/16073614.2019.1617175
- Description: This article reflects on the translation of Lewis Carroll’s Alice’s Adventures in Wonderland into the isiNdebele language of Zimbabwe. The isiNdebele translation, Insumansumane zika-Alice, is one of the numerous translations produced towards the 150th commemorative exhibition of Carroll’s legacy following the publication of Wonderland in 1865. The translations resulted in Wonderland becoming one of the most translated English novels, thereby vindicating the ‘universal-child hypothesis’ propounded by Warren Weaver in an earlier appraisal of Wonderland translations fifty years earlier. Weaver regarded the translation of Wonderland as a measure of the popularity of the text among children, who are arguably fascinated by Alice, with whom they are assumed to identify. This article problematises this argument in the light of most translations being initiated by non-mother-tongue speakers of target languages. It is argued that Alice’s worldwide appeal should not be taken for granted as a universal one, partly because of her particular identity, which is different from the diverse target readers. Therefore, the question of whether Alice can really become African reflects on the domestication approach that was adopted by the isiNdebele translator, among others. Special attention is paid to proper nouns and other complex features characterising Carroll’s language usage.
- Full Text:
- Date Issued: 2019
The Trope of the Child: Rereading Trauma, Subjectivity and Embodiment in Contemporary Child-Centred African Narratives by Ahmadou Kourouma, Chris Abani, K. Sello Duiker and Yvonne Vera
- Authors: Njovane, Thandokazi
- Date: 2019
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/164557 , vital:41134 , doi:10.21504/10962/164557
- Description: Thesis (PhD)--Rhodes University, Humanities, Literary Studies in English, 2019
- Full Text:
- Date Issued: 2019
- Authors: Njovane, Thandokazi
- Date: 2019
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/164557 , vital:41134 , doi:10.21504/10962/164557
- Description: Thesis (PhD)--Rhodes University, Humanities, Literary Studies in English, 2019
- Full Text:
- Date Issued: 2019
The trophic and spatial ecology of a sympatric dasyatid community at a remote Atoll, Seychelles
- Authors: Elston, Chantel
- Date: 2019
- Subjects: Dasyatidae -- Seychelles -- Ecology , Rays (Fishes) -- Seychelles -- Ecology , Ecology -- Seychelles , Dasyatidae -- Seychelles -- Conservation , Pastinachus sephen , Urogymnus granulatus , Urogymnus asperrimus
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/95756 , vital:31196 , DOI https://doi.org/10.21504/10962/95756
- Description: Batoid populations are declining globally but the paucity of information makes management or conservation efforts difficult. Additionally, batoids are mesopredators and are hypothesised to play important ecological roles, but a comprehensive understanding of these roles is also limited. Therefore, information on batoid habitat use, foraging ecology, and resource partitioning is needed. St. Joseph Atoll is a relatively pristine ecosystem that hosts a sympatric dasyatid community (Pastinachus sephen, Urogymnus granulatus, and U. asperrimus). Passive acoustic telemetry identified high levels of long-term site affinity by both juvenile and adult dasyatids to St. Joseph Atoll. Dispersal from the atoll by larger juveniles was also evident. Juveniles displayed restricted horizontal movements in the atoll, but the extent of these movements differed seasonally. Stomach content and stable isotope analyses identified inter-specific prey partitioning (P. sephen juveniles were mollusc specialists and U. granulatus juveniles were crustacean specialists) and intra-specific prey partitioning. Juveniles were reliant upon a seagrass-based food web, whereas adults were reliant on phytoplankton-based food web. Adults fed at higher trophic levels compared to juveniles (mean of 4.6 and 3.4 respectively). Juvenile dasyatids preferentially selected the shallow reef at habitat of the atoll, where there was no evidence for inter-specific habitat partitioning (individuals co-occurred randomly with con-and hetero-specifics). Conversely, resident adults were more reliant on the deeper lagoon. Juveniles selected the reef at habitat likely because it provided refuge from predation and foraging opportunities. However, juveniles were also detected in the lagoon habitat and this appeared to be necessitated by physical factors as they were detected more frequently in the lagoon at low tides and when temperatures on the reef fats became too warm or too cold. All results together suggest that St. Joseph Atoll is a nursery area for these dasyatids. Juveniles may be limited by resources as prey was partitioned between species. However, top-down control by larger sharks was likely a significant influence on habitat selection, as was the physical effects of tide and temperature. Finally, St. Joseph Atoll is suitable for the designation of a Marine Protected Area, which would likely confer high conservation benefits to this dasyatid community.
- Full Text:
- Date Issued: 2019
- Authors: Elston, Chantel
- Date: 2019
- Subjects: Dasyatidae -- Seychelles -- Ecology , Rays (Fishes) -- Seychelles -- Ecology , Ecology -- Seychelles , Dasyatidae -- Seychelles -- Conservation , Pastinachus sephen , Urogymnus granulatus , Urogymnus asperrimus
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/95756 , vital:31196 , DOI https://doi.org/10.21504/10962/95756
- Description: Batoid populations are declining globally but the paucity of information makes management or conservation efforts difficult. Additionally, batoids are mesopredators and are hypothesised to play important ecological roles, but a comprehensive understanding of these roles is also limited. Therefore, information on batoid habitat use, foraging ecology, and resource partitioning is needed. St. Joseph Atoll is a relatively pristine ecosystem that hosts a sympatric dasyatid community (Pastinachus sephen, Urogymnus granulatus, and U. asperrimus). Passive acoustic telemetry identified high levels of long-term site affinity by both juvenile and adult dasyatids to St. Joseph Atoll. Dispersal from the atoll by larger juveniles was also evident. Juveniles displayed restricted horizontal movements in the atoll, but the extent of these movements differed seasonally. Stomach content and stable isotope analyses identified inter-specific prey partitioning (P. sephen juveniles were mollusc specialists and U. granulatus juveniles were crustacean specialists) and intra-specific prey partitioning. Juveniles were reliant upon a seagrass-based food web, whereas adults were reliant on phytoplankton-based food web. Adults fed at higher trophic levels compared to juveniles (mean of 4.6 and 3.4 respectively). Juvenile dasyatids preferentially selected the shallow reef at habitat of the atoll, where there was no evidence for inter-specific habitat partitioning (individuals co-occurred randomly with con-and hetero-specifics). Conversely, resident adults were more reliant on the deeper lagoon. Juveniles selected the reef at habitat likely because it provided refuge from predation and foraging opportunities. However, juveniles were also detected in the lagoon habitat and this appeared to be necessitated by physical factors as they were detected more frequently in the lagoon at low tides and when temperatures on the reef fats became too warm or too cold. All results together suggest that St. Joseph Atoll is a nursery area for these dasyatids. Juveniles may be limited by resources as prey was partitioned between species. However, top-down control by larger sharks was likely a significant influence on habitat selection, as was the physical effects of tide and temperature. Finally, St. Joseph Atoll is suitable for the designation of a Marine Protected Area, which would likely confer high conservation benefits to this dasyatid community.
- Full Text:
- Date Issued: 2019
The tropical environment and malaria in southwestern Nigeria, 1861 – 1960
- Authors: Adetiba, Adedamola Seun
- Date: 2019
- Subjects: Diseases and history -- Africa , Diseases and history -- Nigeria , Medical anthropology -- Africa , Medical anthropology -- Nigeria , Malaria -- Social aspects -- Nigeria , Malaria -- Nigeria -- History , Nigeria -- History , Imperialism -- Health aspects , Medicine -- Colonies -- Great Britain -- History
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/76564 , vital:30605
- Description: This thesis is a social history of malaria in southwestern Nigeria. It contributes to the burgeoning literature in the historiography of medicine, specifically the medicine and empire debate. Key to the issues raised in this thesis is the extent to which the limitations in colonial medical policies, most especially malaria control programmes, inspired critical and ingenious responses from African nationalists, doctors, patients, research volunteers, and indigenous medical practitioners. Challenged by a wide range of diseases and a paucity of health facilities and disease control schemes, African rural dwellers became medical pluralists in the ways they imagined and appropriated ideas of Western medicine alongside their indigenous medical practices. Beginning with a detailed historical exploration of the issues that informed the introduction of curative and preventive medicine in southwestern Nigeria, this thesis reveals the focus of colonial medicine. It exposes the one-sided nature of medical services in colonial spaces like southwestern Nigeria and the ways it shaped multifaceted responses from Africans, who were specifically side-lined till the 1950s when the rural medical service scheme was introduced. The focus of colonial medicine is drawn from relatively rich but often subjective historical evidence, such as a plethora of official reports of the department of medical and sanitary services, official correspondences within the colonial government in Lagos and Nigeria, and between the colonial government and the colonial office in the United Kingdom. Details of African responses to medical policies were garnered from newspaper publications and correspondences between the African public and the colonial government in Lagos. They reveal very interesting details of the ways Africans imagined, reimagined, and appropriated malaria control ideas and schemes. The central argument in this thesis is that attempts to control malaria in southwestern Nigeria till the 1950s, were shaped by a single concern to ameliorate the implications of the disease on the colonial state. It argues that this one-sided nature of malaria control programme informed the basis for medical pluralism in most rural spaces where African communities became patrons and sponsors of Western medicine and at the same time custodians of their indigenous medical practices. The series of justifications for the sustenance of these services were reinforced on the basis of the failure of the colonial state to guarantee the health needs of their colonial subjects. The aim of the thesis is to reinforce arguments that portray colonial medicine as a “tool of empire” but goes a bit further to explain the extent to which Africans related to this reality. It states quite categorically that Africans were not docile and silent, but that they acted decisively in ways that suited their varied interests and courses.
- Full Text:
- Date Issued: 2019
- Authors: Adetiba, Adedamola Seun
- Date: 2019
- Subjects: Diseases and history -- Africa , Diseases and history -- Nigeria , Medical anthropology -- Africa , Medical anthropology -- Nigeria , Malaria -- Social aspects -- Nigeria , Malaria -- Nigeria -- History , Nigeria -- History , Imperialism -- Health aspects , Medicine -- Colonies -- Great Britain -- History
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/76564 , vital:30605
- Description: This thesis is a social history of malaria in southwestern Nigeria. It contributes to the burgeoning literature in the historiography of medicine, specifically the medicine and empire debate. Key to the issues raised in this thesis is the extent to which the limitations in colonial medical policies, most especially malaria control programmes, inspired critical and ingenious responses from African nationalists, doctors, patients, research volunteers, and indigenous medical practitioners. Challenged by a wide range of diseases and a paucity of health facilities and disease control schemes, African rural dwellers became medical pluralists in the ways they imagined and appropriated ideas of Western medicine alongside their indigenous medical practices. Beginning with a detailed historical exploration of the issues that informed the introduction of curative and preventive medicine in southwestern Nigeria, this thesis reveals the focus of colonial medicine. It exposes the one-sided nature of medical services in colonial spaces like southwestern Nigeria and the ways it shaped multifaceted responses from Africans, who were specifically side-lined till the 1950s when the rural medical service scheme was introduced. The focus of colonial medicine is drawn from relatively rich but often subjective historical evidence, such as a plethora of official reports of the department of medical and sanitary services, official correspondences within the colonial government in Lagos and Nigeria, and between the colonial government and the colonial office in the United Kingdom. Details of African responses to medical policies were garnered from newspaper publications and correspondences between the African public and the colonial government in Lagos. They reveal very interesting details of the ways Africans imagined, reimagined, and appropriated malaria control ideas and schemes. The central argument in this thesis is that attempts to control malaria in southwestern Nigeria till the 1950s, were shaped by a single concern to ameliorate the implications of the disease on the colonial state. It argues that this one-sided nature of malaria control programme informed the basis for medical pluralism in most rural spaces where African communities became patrons and sponsors of Western medicine and at the same time custodians of their indigenous medical practices. The series of justifications for the sustenance of these services were reinforced on the basis of the failure of the colonial state to guarantee the health needs of their colonial subjects. The aim of the thesis is to reinforce arguments that portray colonial medicine as a “tool of empire” but goes a bit further to explain the extent to which Africans related to this reality. It states quite categorically that Africans were not docile and silent, but that they acted decisively in ways that suited their varied interests and courses.
- Full Text:
- Date Issued: 2019
The twice-told tale: Ethiopia, race, and the veil of signs
- Authors: Klopper, Dirk
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/458615 , vital:75756 , https://hdl.handle.net/10520/EJC-1b96674043
- Description: This paper examines the retelling of the story of Ethiopia in the Ethiopianist and pan-Africanist movements of the mid-nineteenth to mid-twentieth centuries. In this story, the trope of Ethiopia, which had been deployed in ancient history to signify Africa as racial other, is appropriated by Africans living on the continent and in the diaspora to signify the liberation of African people from both colonial rule and cultural alienation. Nevertheless, while Ethiopia is deployed as a trope of racial difference and race-based cultural aspirations, the demarcation it marks between self and other is indeterminate and ambiguous. This demarcation is unstable insofar as the trope of Ethiopia, and what it signifies in the world of the mid-nineteenth century to the mid-twentieth century, is defined not only by the cultural or religious meanings accrued over a period of almost thirty centuries, but also by the imperial politics of modern Ethiopia in the period under consideration. This politics crystallises around the coronation of Haile Selassie as emperor of Ethiopia in 1930, and marks both the culmination of the historical deployment of the Ethiopian trope and its moment of deconstruction.
- Full Text:
- Date Issued: 2019
- Authors: Klopper, Dirk
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/458615 , vital:75756 , https://hdl.handle.net/10520/EJC-1b96674043
- Description: This paper examines the retelling of the story of Ethiopia in the Ethiopianist and pan-Africanist movements of the mid-nineteenth to mid-twentieth centuries. In this story, the trope of Ethiopia, which had been deployed in ancient history to signify Africa as racial other, is appropriated by Africans living on the continent and in the diaspora to signify the liberation of African people from both colonial rule and cultural alienation. Nevertheless, while Ethiopia is deployed as a trope of racial difference and race-based cultural aspirations, the demarcation it marks between self and other is indeterminate and ambiguous. This demarcation is unstable insofar as the trope of Ethiopia, and what it signifies in the world of the mid-nineteenth century to the mid-twentieth century, is defined not only by the cultural or religious meanings accrued over a period of almost thirty centuries, but also by the imperial politics of modern Ethiopia in the period under consideration. This politics crystallises around the coronation of Haile Selassie as emperor of Ethiopia in 1930, and marks both the culmination of the historical deployment of the Ethiopian trope and its moment of deconstruction.
- Full Text:
- Date Issued: 2019
The use of filter-feeding fish (Clarias gariepinus and Oreochromis mossambicus) to remove microalgae from brewery effluent treatment ponds
- Authors: Nombembe, Lwazi
- Date: 2019
- Subjects: Clarias gariepinus -- Food , Mozambique tilapia -- Food , Water -- Purification -- South Africa , Algae -- Biotechnology -- South Africa , Microalgae -- Biotechnology-- South Africa , Brewery waste -- South Africa , Fish culture -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/95745 , vital:31194
- Description: The removal of microalgae from high rate algal ponds (HRAP) in waste-water treatment systems remains a constraint to their use in effluent treatment systems. Conventional algae harvesting methods often have high energy demands, take up lots of space, are expensive to operate or are time consuming. The aim of the study was to determine if fish such as Clarias gariepinus and Oreochromis mossambicus, could be used to remove microalgae from waste-water treatment ponds (in the absence/presence of a flocculent in the former and in the absence or presence of pH moderation in the latter), and to investigate the subsequent influence of algae concentration on several water quality parameters. The age of Clarias gariepinus (3-12 months) had a positive relationship with the distance between gill rakers (98.27 to 163.34 μm; y=90.576+4.823*x: R²=0.549; F(1,18)=21.867; p<0.001) and these data suggested that these fish might be efficient at removing algae from HRAP effluent. However, this was not the case, even with flocculent application (but this result might have been confounded by very high pH readings, at which flocculation is less likely to occur). Oreochromis mossambicus removed some of this algae, but the pH was too high for tilapia culture. It was not possible to moderate the increase in pH by keeping tanks in the dark and thus preventing photosynthesis; but pH fluctuation in HRAP effluent could be moderated using CO2 sparging in an attempt to make the environment more hospitable for tilapia (the average pH that was moderated with CO2 was 8.43±0.06, whereas the unmoderated average was 10.65±0.06). However, pH moderation using CO2 sparging did not increase the rate at which algae were removed by O. mossambicus; rather, it compromised O2 concentration which dropped to 4.17±1.26 mg/l after five hours of CO2 sparging, whereas it increased to 20.50±1.41 mg/l in treatments with unadjusted pH over the same period. Fish can be used to remove algae from treated effluent, and Oreochromis mossambicus remains a recommended species. Future work needs to investigate moderating fluctuations in pH and O2 concentration to further facilitate this method of algae removal.
- Full Text:
- Date Issued: 2019
- Authors: Nombembe, Lwazi
- Date: 2019
- Subjects: Clarias gariepinus -- Food , Mozambique tilapia -- Food , Water -- Purification -- South Africa , Algae -- Biotechnology -- South Africa , Microalgae -- Biotechnology-- South Africa , Brewery waste -- South Africa , Fish culture -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/95745 , vital:31194
- Description: The removal of microalgae from high rate algal ponds (HRAP) in waste-water treatment systems remains a constraint to their use in effluent treatment systems. Conventional algae harvesting methods often have high energy demands, take up lots of space, are expensive to operate or are time consuming. The aim of the study was to determine if fish such as Clarias gariepinus and Oreochromis mossambicus, could be used to remove microalgae from waste-water treatment ponds (in the absence/presence of a flocculent in the former and in the absence or presence of pH moderation in the latter), and to investigate the subsequent influence of algae concentration on several water quality parameters. The age of Clarias gariepinus (3-12 months) had a positive relationship with the distance between gill rakers (98.27 to 163.34 μm; y=90.576+4.823*x: R²=0.549; F(1,18)=21.867; p<0.001) and these data suggested that these fish might be efficient at removing algae from HRAP effluent. However, this was not the case, even with flocculent application (but this result might have been confounded by very high pH readings, at which flocculation is less likely to occur). Oreochromis mossambicus removed some of this algae, but the pH was too high for tilapia culture. It was not possible to moderate the increase in pH by keeping tanks in the dark and thus preventing photosynthesis; but pH fluctuation in HRAP effluent could be moderated using CO2 sparging in an attempt to make the environment more hospitable for tilapia (the average pH that was moderated with CO2 was 8.43±0.06, whereas the unmoderated average was 10.65±0.06). However, pH moderation using CO2 sparging did not increase the rate at which algae were removed by O. mossambicus; rather, it compromised O2 concentration which dropped to 4.17±1.26 mg/l after five hours of CO2 sparging, whereas it increased to 20.50±1.41 mg/l in treatments with unadjusted pH over the same period. Fish can be used to remove algae from treated effluent, and Oreochromis mossambicus remains a recommended species. Future work needs to investigate moderating fluctuations in pH and O2 concentration to further facilitate this method of algae removal.
- Full Text:
- Date Issued: 2019
The use of image processing to determine cell defects in polycrystalline solar modules
- Authors: Banda, Peter
- Date: 2019
- Subjects: Polycrystals
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/36573 , vital:33996
- Description: This research aims to use image processingtodetermine cell defects in polycrystalline solar modules. Image processing is a process of enhancing images for differentapplications. One domain that seems to not yet utilise the use of image processing, is photovoltaics. An increased use of fossil fuels is damaging the earth and a call to protect the earth has resulted in the emergence of pollutant-free technologies such as polycrystalline photovoltaic (PV) cells, which are connected to make up solar modules. However, defects often affect the performance of PV cells and consequently solar modules. Electroluminescence (EL) images are used to examine polycrystalline solar (PV) modules to determine if the modules are defective. The main research question that this research addressed is“How can an image processing technique be used to effectively identify defective polycrystalline PV cells from EL images of such cells?“. The experimental research methodology was used to address the main research question. The initial investigation into the problem revealed that certain sectors within industry, as well as the Physics Department at Nelson Mandela University(NMU), do not currently utiliseimage processing when examining EL images of solar modules. The current process is a tedious, manual process whereby solar modules are manually inspected. An analysis of the current processes enabled the identification of ways in which to automatically examine EL images of solar modules. An analysis of literatureprovided a better understanding of the different techniques that are used to examine solar modules, and it was identified how image processing can be applied to EL images. Further analysis of literatureprovided a better understanding of image processing and how image classification experiments using Deep Learning (DL) as an image processing technique can be used to address the main research question. The outcome of the experiments conducted in this research weredifferentadaptive models(LeNet, MobileNet, Xception)that can classify EL images of PV cellsaccording to known standardsused by the Physics Department at NMU. The known standards yielded four classes; normal, uncritical, critical and very critical, which were used for the classification of EL images of PV cells. The adaptive models were evaluated to obtain the precision, recall and F1–scoreof the models.The precession, recall, and F1–score were required to determine how effective the models were in identifying defective PV cells from EL images.The results indicated that an image processing technique canbe used to identify defective polycrystalline PV cells from EL images of such cells. However, further research needs to be conducted to improve the effectiveness of the adaptive models.
- Full Text:
- Date Issued: 2019
- Authors: Banda, Peter
- Date: 2019
- Subjects: Polycrystals
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/36573 , vital:33996
- Description: This research aims to use image processingtodetermine cell defects in polycrystalline solar modules. Image processing is a process of enhancing images for differentapplications. One domain that seems to not yet utilise the use of image processing, is photovoltaics. An increased use of fossil fuels is damaging the earth and a call to protect the earth has resulted in the emergence of pollutant-free technologies such as polycrystalline photovoltaic (PV) cells, which are connected to make up solar modules. However, defects often affect the performance of PV cells and consequently solar modules. Electroluminescence (EL) images are used to examine polycrystalline solar (PV) modules to determine if the modules are defective. The main research question that this research addressed is“How can an image processing technique be used to effectively identify defective polycrystalline PV cells from EL images of such cells?“. The experimental research methodology was used to address the main research question. The initial investigation into the problem revealed that certain sectors within industry, as well as the Physics Department at Nelson Mandela University(NMU), do not currently utiliseimage processing when examining EL images of solar modules. The current process is a tedious, manual process whereby solar modules are manually inspected. An analysis of the current processes enabled the identification of ways in which to automatically examine EL images of solar modules. An analysis of literatureprovided a better understanding of the different techniques that are used to examine solar modules, and it was identified how image processing can be applied to EL images. Further analysis of literatureprovided a better understanding of image processing and how image classification experiments using Deep Learning (DL) as an image processing technique can be used to address the main research question. The outcome of the experiments conducted in this research weredifferentadaptive models(LeNet, MobileNet, Xception)that can classify EL images of PV cellsaccording to known standardsused by the Physics Department at NMU. The known standards yielded four classes; normal, uncritical, critical and very critical, which were used for the classification of EL images of PV cells. The adaptive models were evaluated to obtain the precision, recall and F1–scoreof the models.The precession, recall, and F1–score were required to determine how effective the models were in identifying defective PV cells from EL images.The results indicated that an image processing technique canbe used to identify defective polycrystalline PV cells from EL images of such cells. However, further research needs to be conducted to improve the effectiveness of the adaptive models.
- Full Text:
- Date Issued: 2019
The use of insecticides and cultural control for the management of soil-borne pests during plantation establishment
- Authors: Siwela, Evidence Miyelani
- Date: 2019
- Subjects: Insecticides , Plant diseases Pests -- Control Pesticides
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/43446 , vital:36882
- Description: Over the past decades, the productivity of South African forestry plantations has been negatively impacted by abiotic (fire, hail, wind, frost, drought etc.) and biotic factors (pests and diseases). The biotic component of insect pests and pathogens cause significant loss to the forestry industry and this affects the productivity, financial viability and long-term sustainability of plantations. Common establishment insect pests and diseases in South Africa include the pine bark beetle (Hylastes angustatus), cutworms (Agrotis spp), white grubs (Scarabaeidae larvae), rhizina root rot (Rhizina undulata), fusarium pitch canker (Fusarium circinatum), and pine dieback (Diplodia pinea). Soil-borne pests, mainly white grubs and cutworms can contribute to high seedling mortality following the re-establishment of eucalypts and wattle. Synthetic insecticides used for their control include alpha-cypermethrin, deltamethrin, and imidacloprid. However, all these insecticides are considered highly hazardous to the environment and/or human health and can no longer be considered for use in South African plantations. A need has therefore arisen to find and screen alternative products (synthetic and/or natural), that are not only environmentally safe for use, but also effective for the control of soil-borne pests during plantation establishment. In addition, these products can then be combined with other control mechanisms (such as cultural and biological control) to form an integrated pest management strategy. To address the above, a series of research trials were implemented with the outcomes discussed below. Two trials were implemented in KwaZulu-Natal (Demagtenberg) and Mpumalanga (Klipkraal) to determine if seedling size in combination with, or without an insecticide would result in improved survival of Pinus Patula. The main factors tested were Root Plug Volume (36 cm3 versus 103 cm3), Seedling Age (Standard [smaller] versus Older [larger]), and Pesticide application (untreated versus treated). Seedling quality was assessed in terms of Shoot:Root ratio, optimum Height (Ht in cm), and root collar diameter (Rcd in mm) before planting, with tree growth variates measured at planting, and then at regular intervals. The final measurements were taken at 7 years and 2 months for Demagtenberg and 5 years and 1 month for Klipkraal. For both trials, the Root Growth Potential (RGP) and total Plant Quality Index (PQI) indicated that Root Plug Volume 36 cm3 and Seedling Age (SA)_Standard (smaller) had a better Sturdiness ratio and Shoot:Root ratio compared to that of Root Plug Volume 103 cm3 and Seedling Age (SA)_Older (larger), with these benefits translated into improved field performance. The diameter at breast height (Dbh), Basal area (BA), Stocking and Volume indicated that SA_Standard and Root Plug Volume 36 cm3 resulted in better survival and growth than that of SA_Older (larger) seedlings and Root Plug Volume 103 cm3. The application of a Pesticide resulted in improved survival and growth at Klipkraal, but not at Demagtenberg. This indicated the presence of soil-borne pests at this site. In addition, the interaction between Pesticide application and SA_Standard resulted in a significantly larger BA than all other treatments only at Klipkraal, which indicates that both improved seedling quality and pesticides contributed to improved performance. One trial was established to Eucalyptus dunnii William Dunn at Umvoti North to investigate the effectiveness of the synthetic insecticides (deltamethrin, clothianidin, imidacloprid, imidacloprid + fertilizer, imidacloprid + clothianidin + fertilizer) and two natural products (azadirachtin and potassium silicate) for the control of soil-borne pests following planting. Groundline diameter (Gld), Height (Ht) and survival were assessed over a six-month period. Despite the selection of a site known to have a high incidence of soil-borne pests, few soil-borne pest were detected on the site for the trial duration, with no treatment differences observed for any of the tree growth variates. Significant differences were observed for foliar discolouration (possible phytotoxicity), however, these results were inconclusive as majority of the affected treatments (those that survived) showed full recovery. Three-month results from 12 eucalypt trials in KwaZulu-Natal, South Africa were compared to determine the benefits (including costs) of insecticides for the control of soil-borne pests. The 12 trials were selected to represent different physiographic regions, mainly within the warm temperate regions where white grubs and cutworms are likely to occur. Data for the trials were obtained from previous management research (published documents) and included six where mortality was the only variate assessed, with the Ht and Gld also assessed in the remaining six trials. There was a ≥ 2.5% increase in survival in seven of the 12 trials through the use of insecticides relative to the control, although only four of these seven were statistically significant. Of the 12 trials, the use of insecticides resulted in > 90% survival compared to the control at Mistley (93 versus 83%), Bloemendal (96 versus 62%) and Enon (burn) (96 versus 89%). At Garfield, Vulindlela, and Baynesfield, survival in both the treated and untreated treatments was below 90%, whereas both the treated and untreated treatments were above 90% at Rustig, Greenhill, Enon (slash), Umvoti, Dargle and Umvoti North. This data indicates that where soil-borne pests are present, the application of an insecticide is beneficial. Due to the costs associated with insecticide application, the challenge will be to determine which are high-risk sites that require treatment with an insecticide. Results from these trials indicate that on sites where soil-borne pests are present (and active), the application of insecticides is beneficial. However, even if present, the level of impact is less obvious, and possibly influenced by life cycle stage, site management and climate. The testing of alternative and less highly hazardous insecticides indicated the potential future use of insecticides in terms of limited seedling phytotoxicity (some of the products tested). To understand more fully the extent of their efficacy, these products would need to be re-tested again on sites where soil-borne pests are active. Optimum establishment practices, together with the planting of quality seedlings and application of an approved insecticide, will all contribute to improved survival and growth. Perhaps the biggest challenge will be the determination of soil pest activity, such that the application of pesticides can be limited to those sites where control is necessary..
- Full Text:
- Date Issued: 2019
- Authors: Siwela, Evidence Miyelani
- Date: 2019
- Subjects: Insecticides , Plant diseases Pests -- Control Pesticides
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/43446 , vital:36882
- Description: Over the past decades, the productivity of South African forestry plantations has been negatively impacted by abiotic (fire, hail, wind, frost, drought etc.) and biotic factors (pests and diseases). The biotic component of insect pests and pathogens cause significant loss to the forestry industry and this affects the productivity, financial viability and long-term sustainability of plantations. Common establishment insect pests and diseases in South Africa include the pine bark beetle (Hylastes angustatus), cutworms (Agrotis spp), white grubs (Scarabaeidae larvae), rhizina root rot (Rhizina undulata), fusarium pitch canker (Fusarium circinatum), and pine dieback (Diplodia pinea). Soil-borne pests, mainly white grubs and cutworms can contribute to high seedling mortality following the re-establishment of eucalypts and wattle. Synthetic insecticides used for their control include alpha-cypermethrin, deltamethrin, and imidacloprid. However, all these insecticides are considered highly hazardous to the environment and/or human health and can no longer be considered for use in South African plantations. A need has therefore arisen to find and screen alternative products (synthetic and/or natural), that are not only environmentally safe for use, but also effective for the control of soil-borne pests during plantation establishment. In addition, these products can then be combined with other control mechanisms (such as cultural and biological control) to form an integrated pest management strategy. To address the above, a series of research trials were implemented with the outcomes discussed below. Two trials were implemented in KwaZulu-Natal (Demagtenberg) and Mpumalanga (Klipkraal) to determine if seedling size in combination with, or without an insecticide would result in improved survival of Pinus Patula. The main factors tested were Root Plug Volume (36 cm3 versus 103 cm3), Seedling Age (Standard [smaller] versus Older [larger]), and Pesticide application (untreated versus treated). Seedling quality was assessed in terms of Shoot:Root ratio, optimum Height (Ht in cm), and root collar diameter (Rcd in mm) before planting, with tree growth variates measured at planting, and then at regular intervals. The final measurements were taken at 7 years and 2 months for Demagtenberg and 5 years and 1 month for Klipkraal. For both trials, the Root Growth Potential (RGP) and total Plant Quality Index (PQI) indicated that Root Plug Volume 36 cm3 and Seedling Age (SA)_Standard (smaller) had a better Sturdiness ratio and Shoot:Root ratio compared to that of Root Plug Volume 103 cm3 and Seedling Age (SA)_Older (larger), with these benefits translated into improved field performance. The diameter at breast height (Dbh), Basal area (BA), Stocking and Volume indicated that SA_Standard and Root Plug Volume 36 cm3 resulted in better survival and growth than that of SA_Older (larger) seedlings and Root Plug Volume 103 cm3. The application of a Pesticide resulted in improved survival and growth at Klipkraal, but not at Demagtenberg. This indicated the presence of soil-borne pests at this site. In addition, the interaction between Pesticide application and SA_Standard resulted in a significantly larger BA than all other treatments only at Klipkraal, which indicates that both improved seedling quality and pesticides contributed to improved performance. One trial was established to Eucalyptus dunnii William Dunn at Umvoti North to investigate the effectiveness of the synthetic insecticides (deltamethrin, clothianidin, imidacloprid, imidacloprid + fertilizer, imidacloprid + clothianidin + fertilizer) and two natural products (azadirachtin and potassium silicate) for the control of soil-borne pests following planting. Groundline diameter (Gld), Height (Ht) and survival were assessed over a six-month period. Despite the selection of a site known to have a high incidence of soil-borne pests, few soil-borne pest were detected on the site for the trial duration, with no treatment differences observed for any of the tree growth variates. Significant differences were observed for foliar discolouration (possible phytotoxicity), however, these results were inconclusive as majority of the affected treatments (those that survived) showed full recovery. Three-month results from 12 eucalypt trials in KwaZulu-Natal, South Africa were compared to determine the benefits (including costs) of insecticides for the control of soil-borne pests. The 12 trials were selected to represent different physiographic regions, mainly within the warm temperate regions where white grubs and cutworms are likely to occur. Data for the trials were obtained from previous management research (published documents) and included six where mortality was the only variate assessed, with the Ht and Gld also assessed in the remaining six trials. There was a ≥ 2.5% increase in survival in seven of the 12 trials through the use of insecticides relative to the control, although only four of these seven were statistically significant. Of the 12 trials, the use of insecticides resulted in > 90% survival compared to the control at Mistley (93 versus 83%), Bloemendal (96 versus 62%) and Enon (burn) (96 versus 89%). At Garfield, Vulindlela, and Baynesfield, survival in both the treated and untreated treatments was below 90%, whereas both the treated and untreated treatments were above 90% at Rustig, Greenhill, Enon (slash), Umvoti, Dargle and Umvoti North. This data indicates that where soil-borne pests are present, the application of an insecticide is beneficial. Due to the costs associated with insecticide application, the challenge will be to determine which are high-risk sites that require treatment with an insecticide. Results from these trials indicate that on sites where soil-borne pests are present (and active), the application of insecticides is beneficial. However, even if present, the level of impact is less obvious, and possibly influenced by life cycle stage, site management and climate. The testing of alternative and less highly hazardous insecticides indicated the potential future use of insecticides in terms of limited seedling phytotoxicity (some of the products tested). To understand more fully the extent of their efficacy, these products would need to be re-tested again on sites where soil-borne pests are active. Optimum establishment practices, together with the planting of quality seedlings and application of an approved insecticide, will all contribute to improved survival and growth. Perhaps the biggest challenge will be the determination of soil pest activity, such that the application of pesticides can be limited to those sites where control is necessary..
- Full Text:
- Date Issued: 2019
The use of liquid petroleum gas (LPG) as an alternative automotive fuel in South Africa towards 2030
- Authors: Ognianov, Nadine
- Date: 2019
- Subjects: Automobiles -- Motors -- Exhaust gas -- Economic aspects -- South Africa , Automobiles -- Motors -- Exhaust gas -- Environmental aspects -- South Africa , Automobiles -- Fuel consumption -- Economic aspects -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/42979 , vital:36716
- Description: South Africa is considered to be the economic power house of Africa, yet still lags behind when implementing energy efficient solutions. This can be attributed to bureaucracy and red tape. South Africa is the smallest importer and user of liquefied petroleum gas in Africa. Algeria is the biggest importer and consumer on a domestic scale. The use of liquid petroleum gas as an automotive fuel is not a new concept, either on this continent or the rest of the world. Vehicles have been driving on autogas for many decades and have seen various technological changes and improvements along the way. The latest autogas technology has been tried, tested and improved to be in line with Euro 5 standards. The purpose of the paper is to highlight all the benefits to motorists and to encourage the adoption of liquid petroleum gas (Autogas) as an automotive fuel. The literature review highlights the financial and environmental benefits, as well as identifying the barriers to adoption as well as the critical success factors for adopting autogas as a transport fuel. This resulted in the identification of six independent variables, namely cost, environmental impact, government legislation, infrastructure, public demand and product availability. These variables were then used to construct a conceptual framework to test the perceived outcome, which was the dependant variable.
- Full Text:
- Date Issued: 2019
The use of liquid petroleum gas (LPG) as an alternative automotive fuel in South Africa towards 2030
- Authors: Ognianov, Nadine
- Date: 2019
- Subjects: Automobiles -- Motors -- Exhaust gas -- Economic aspects -- South Africa , Automobiles -- Motors -- Exhaust gas -- Environmental aspects -- South Africa , Automobiles -- Fuel consumption -- Economic aspects -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/42979 , vital:36716
- Description: South Africa is considered to be the economic power house of Africa, yet still lags behind when implementing energy efficient solutions. This can be attributed to bureaucracy and red tape. South Africa is the smallest importer and user of liquefied petroleum gas in Africa. Algeria is the biggest importer and consumer on a domestic scale. The use of liquid petroleum gas as an automotive fuel is not a new concept, either on this continent or the rest of the world. Vehicles have been driving on autogas for many decades and have seen various technological changes and improvements along the way. The latest autogas technology has been tried, tested and improved to be in line with Euro 5 standards. The purpose of the paper is to highlight all the benefits to motorists and to encourage the adoption of liquid petroleum gas (Autogas) as an automotive fuel. The literature review highlights the financial and environmental benefits, as well as identifying the barriers to adoption as well as the critical success factors for adopting autogas as a transport fuel. This resulted in the identification of six independent variables, namely cost, environmental impact, government legislation, infrastructure, public demand and product availability. These variables were then used to construct a conceptual framework to test the perceived outcome, which was the dependant variable.
- Full Text:
- Date Issued: 2019