Determinants of rural households’ diversification of livelihood strategies: a case of Intsika Yethu farmers of the Eastern Cape province, South Africa
- Authors: Munhenga, Daniel
- Date: 2014
- Subjects: Sustainable development -- South Africa -- Eastern Cape , Economic development projects -- South Africa -- Eastern Cape , Farm management -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc Agric (Agricultural Economics)
- Identifier: vital:11220 , http://hdl.handle.net/10353/d1019818 , Sustainable development -- South Africa -- Eastern Cape , Economic development projects -- South Africa -- Eastern Cape , Farm management -- South Africa -- Eastern Cape
- Description: Despite the continuing perceived economic centrality of agriculture in Intsika Yethu local municipality, rural households engage and pursue diverse non-farm livelihood activities to cope with diverse challenges and risks such as drought. This study assessed the importance of existing livelihood strategies adopted by the different rural households in Intsika Yethu; the link between households’ ownership and access to different ‘assets’; factors determining households’ ability to adopt certain livelihood strategies in the area. A survey of 120 households in six administrative areas and informal discussions with key informants were used to collect demographic data, data on socio-economic activities and factors determining the choice of livelihood strategies of the households in Intsika Yethu. The research findings indicated that only about 10% of the interviewed households relied solely on on-farm livelihood strategy only. Credit, remittances, market distance, affiliating to cooperatives, education and household size have a potential of influencing households to shift from on-farm livelihood strategy to other livelihood strategies. The government may need to promote programs and awareness on how households can diversify their livelihood strategies as a way of coping with economic constraints in the area.
- Full Text:
- Date Issued: 2014
- Authors: Munhenga, Daniel
- Date: 2014
- Subjects: Sustainable development -- South Africa -- Eastern Cape , Economic development projects -- South Africa -- Eastern Cape , Farm management -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc Agric (Agricultural Economics)
- Identifier: vital:11220 , http://hdl.handle.net/10353/d1019818 , Sustainable development -- South Africa -- Eastern Cape , Economic development projects -- South Africa -- Eastern Cape , Farm management -- South Africa -- Eastern Cape
- Description: Despite the continuing perceived economic centrality of agriculture in Intsika Yethu local municipality, rural households engage and pursue diverse non-farm livelihood activities to cope with diverse challenges and risks such as drought. This study assessed the importance of existing livelihood strategies adopted by the different rural households in Intsika Yethu; the link between households’ ownership and access to different ‘assets’; factors determining households’ ability to adopt certain livelihood strategies in the area. A survey of 120 households in six administrative areas and informal discussions with key informants were used to collect demographic data, data on socio-economic activities and factors determining the choice of livelihood strategies of the households in Intsika Yethu. The research findings indicated that only about 10% of the interviewed households relied solely on on-farm livelihood strategy only. Credit, remittances, market distance, affiliating to cooperatives, education and household size have a potential of influencing households to shift from on-farm livelihood strategy to other livelihood strategies. The government may need to promote programs and awareness on how households can diversify their livelihood strategies as a way of coping with economic constraints in the area.
- Full Text:
- Date Issued: 2014
Determinants of the yield curve in South Africa
- Authors: Ngonyama, Nomasomi
- Date: 2014
- Language: English
- Type: Thesis , Masters , M Com
- Identifier: vital:11496
- Description: The yield curve has been the subject of many studies for some time, mainly in predicting recessions, economic growth and inflation. However, scant work is available on what drives the yield spread. Given this, the paper examines the determinants of the yield curve in South Africa by using time series econometric analysis over the period 2000-2012. Some key variables considered include inflation, economic growth, budget deficit, and monetary policy. To separate the long and short run effects, VECM was employed after ensuring stationarity of the series. The study found that a long run relationship exist between the yield spread, inflation, GDP, budget deficit, Repo rate, Real effective exchange rate and a money supply (M1). The Results of this thesis have implications for policy and academic work.
- Full Text:
- Date Issued: 2014
- Authors: Ngonyama, Nomasomi
- Date: 2014
- Language: English
- Type: Thesis , Masters , M Com
- Identifier: vital:11496
- Description: The yield curve has been the subject of many studies for some time, mainly in predicting recessions, economic growth and inflation. However, scant work is available on what drives the yield spread. Given this, the paper examines the determinants of the yield curve in South Africa by using time series econometric analysis over the period 2000-2012. Some key variables considered include inflation, economic growth, budget deficit, and monetary policy. To separate the long and short run effects, VECM was employed after ensuring stationarity of the series. The study found that a long run relationship exist between the yield spread, inflation, GDP, budget deficit, Repo rate, Real effective exchange rate and a money supply (M1). The Results of this thesis have implications for policy and academic work.
- Full Text:
- Date Issued: 2014
Determining factors influencing sales growth in business banking in Buffalo City municipality, South Africa
- Authors: Koneti, Boniswa
- Date: 2014
- Subjects: Direct selling Sales management Marketing channels
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/10993 , vital:26865
- Description: The increase in number of banks entering the South African banking sector has caused the big four banks to lose their market share to the new entrants. As a result, the new entrants in this sector have also had negative effects on the existing banks’ sales growth and net profits. Business banking, in particular, has been one of the departments which has become competitive as it is considered to generate the most revenue from all the different bank departments. Business clients have been targeted as their fees are high compared to normal individual clients and also, their investment sizes are big compared to individuals, hence the increased interest in this section. This then prompts the question, what are the factors influencing sales growth in business banking? This question then brings one to the following sub-problems: Is the pricing offered by the various banks to their business bank customers competitive enough to retain them?; How competent and knowledgeable is the staff dealing with business bank customers in ensuring good relationships with business banking clients?; is the technology used by the banks advanced enough to address the banking requirements of business banking customers? Are business banking customers loyal to their respective banks to ensure repetitive sales? In dealing with the above, the author undertook a research study to determine whether factors such as competitive pricing, competent staff, advanced technology and customer loyalty influence sales growth in business banking in Buffalo City Municipality “BCM”. The sample of 90 business banking customers who were given questionnaires to test the above were from a population of business banking customers in BCM. The author underwent a theoretical and an empirical investigation using the survey method through questionnaires. These questionnaires were distributed to the various financing institutions dealing with business banking clients. The findings of the empirical study suggest that through the use of the hypothesis test, it was concluded that of the four factors, advanced technology and customer loyalty influence sales growth in business banking in BCM. While pricing and competent staff do not influence sales revenue growth.
- Full Text:
- Date Issued: 2014
- Authors: Koneti, Boniswa
- Date: 2014
- Subjects: Direct selling Sales management Marketing channels
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/10993 , vital:26865
- Description: The increase in number of banks entering the South African banking sector has caused the big four banks to lose their market share to the new entrants. As a result, the new entrants in this sector have also had negative effects on the existing banks’ sales growth and net profits. Business banking, in particular, has been one of the departments which has become competitive as it is considered to generate the most revenue from all the different bank departments. Business clients have been targeted as their fees are high compared to normal individual clients and also, their investment sizes are big compared to individuals, hence the increased interest in this section. This then prompts the question, what are the factors influencing sales growth in business banking? This question then brings one to the following sub-problems: Is the pricing offered by the various banks to their business bank customers competitive enough to retain them?; How competent and knowledgeable is the staff dealing with business bank customers in ensuring good relationships with business banking clients?; is the technology used by the banks advanced enough to address the banking requirements of business banking customers? Are business banking customers loyal to their respective banks to ensure repetitive sales? In dealing with the above, the author undertook a research study to determine whether factors such as competitive pricing, competent staff, advanced technology and customer loyalty influence sales growth in business banking in Buffalo City Municipality “BCM”. The sample of 90 business banking customers who were given questionnaires to test the above were from a population of business banking customers in BCM. The author underwent a theoretical and an empirical investigation using the survey method through questionnaires. These questionnaires were distributed to the various financing institutions dealing with business banking clients. The findings of the empirical study suggest that through the use of the hypothesis test, it was concluded that of the four factors, advanced technology and customer loyalty influence sales growth in business banking in BCM. While pricing and competent staff do not influence sales revenue growth.
- Full Text:
- Date Issued: 2014
Determining guidelines for effectively leading culturally diverse teams at Volkswagen South Africa
- Authors: Nkholise, Martha
- Date: 2014
- Subjects: Diversity in the workplace -- South Africa -- Eastern Cape , Multiculturalism
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8732 , http://hdl.handle.net/10948/d1010077 , Diversity in the workplace -- South Africa -- Eastern Cape , Multiculturalism
- Description: South Africa is a society of diverse cultures, and the workplace is one of the few places that serve as a melting pot for these varied cultures. If managed well, cultural diversity has numerous benefits that can help an organisation gain a competitive advantage. However, failure to manage it can pose challenges that can have serious consequences for an organisation. The purpose of this study was to analyse the leadership of cultural diversity at Volkswagen South Africa (VWSA) and identify leadership guidelines to both enhance team performance and reduce the challenges faced by the organisation as a result of this cultural diversity. For the purpose of this study, a culturally diverse team was defined as a team of diverse individuals from different cultures or societies working together to achieve organisational success. The research was conducted by the use of questionnaire using a sample of 200 employees of the VWSA Paint Shop. The sample represents 42 percent of the total population of the Paint Shop. The study discusses the relationship of four leadership styles (Classical Leadership, Transactional Leadership, Transformational Leadership, and Visionary Leadership) with Cultural Diversity. Whilst strong cases were made for Transformational and Transactional Leadership style being the most suitable styles for leading culturally diverse teams, the researcher concluded that no single leadership style would be ideal for effectively leading culturally diverse teams at VWSA. The appropriate leadership style will instead be a hybrid of all leadership styles, thus being a leadership approach that works as a sort of “best practices” of various leadership styles.
- Full Text:
- Date Issued: 2014
- Authors: Nkholise, Martha
- Date: 2014
- Subjects: Diversity in the workplace -- South Africa -- Eastern Cape , Multiculturalism
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8732 , http://hdl.handle.net/10948/d1010077 , Diversity in the workplace -- South Africa -- Eastern Cape , Multiculturalism
- Description: South Africa is a society of diverse cultures, and the workplace is one of the few places that serve as a melting pot for these varied cultures. If managed well, cultural diversity has numerous benefits that can help an organisation gain a competitive advantage. However, failure to manage it can pose challenges that can have serious consequences for an organisation. The purpose of this study was to analyse the leadership of cultural diversity at Volkswagen South Africa (VWSA) and identify leadership guidelines to both enhance team performance and reduce the challenges faced by the organisation as a result of this cultural diversity. For the purpose of this study, a culturally diverse team was defined as a team of diverse individuals from different cultures or societies working together to achieve organisational success. The research was conducted by the use of questionnaire using a sample of 200 employees of the VWSA Paint Shop. The sample represents 42 percent of the total population of the Paint Shop. The study discusses the relationship of four leadership styles (Classical Leadership, Transactional Leadership, Transformational Leadership, and Visionary Leadership) with Cultural Diversity. Whilst strong cases were made for Transformational and Transactional Leadership style being the most suitable styles for leading culturally diverse teams, the researcher concluded that no single leadership style would be ideal for effectively leading culturally diverse teams at VWSA. The appropriate leadership style will instead be a hybrid of all leadership styles, thus being a leadership approach that works as a sort of “best practices” of various leadership styles.
- Full Text:
- Date Issued: 2014
Developing a relational perspective on intergenerational learning
- Authors: Schudel, Ingrid J
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/437161 , vital:73349 , ISBN 978-9086862528 , https://doi.org/10.3920/978-90-8686-802-5_16
- Description: This chapter argues for a critical perspective on the use of lo-cal knowledge and practices in teaching and learning, present-ing some pedagogical thinking tools for reviewing intergenera-tional teaching and learning processes. The chapter highlights five relational elements in teaching and learning processes, including the relationship between individual and community, social and historic contexts, school-based actions and local practices, local and regional/national/global concerns, and fi-nally between local knowledge and abstract school knowledge. These relational elements of learning illustrate how it is possi-ble to mitigate against conservative, over-simplistic or idealistic responses to environmental concerns. This argument is illus-trated through reference to a lesson designed and implement-ed by a school teacher participating in a Rhodes University ac-credited teacher professional development course–the Schools and Sustainability course. This teacher depended substantially on intergenerational communication for her les-son, which supported Grade 1 pupils to research the use of wild vegetables historically in their community and plant these vegetables in their school garden with the support of knowledgeable community members.
- Full Text:
- Date Issued: 2014
- Authors: Schudel, Ingrid J
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/437161 , vital:73349 , ISBN 978-9086862528 , https://doi.org/10.3920/978-90-8686-802-5_16
- Description: This chapter argues for a critical perspective on the use of lo-cal knowledge and practices in teaching and learning, present-ing some pedagogical thinking tools for reviewing intergenera-tional teaching and learning processes. The chapter highlights five relational elements in teaching and learning processes, including the relationship between individual and community, social and historic contexts, school-based actions and local practices, local and regional/national/global concerns, and fi-nally between local knowledge and abstract school knowledge. These relational elements of learning illustrate how it is possi-ble to mitigate against conservative, over-simplistic or idealistic responses to environmental concerns. This argument is illus-trated through reference to a lesson designed and implement-ed by a school teacher participating in a Rhodes University ac-credited teacher professional development course–the Schools and Sustainability course. This teacher depended substantially on intergenerational communication for her les-son, which supported Grade 1 pupils to research the use of wild vegetables historically in their community and plant these vegetables in their school garden with the support of knowledgeable community members.
- Full Text:
- Date Issued: 2014
Developing an understanding of the drivers of bat activity patterns relevant to wind turbines
- Authors: Thwaits, Tiffany Edan
- Date: 2014
- Subjects: Bats -- Behavior -- Climatic factors -- South Africa , Bats -- Ecology -- South Africa -- Eastern Cape , Wind power -- Environmental aspects
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10726 , http://hdl.handle.net/10948/d1020970
- Description: The increasing number of proposed wind farm developments in South Africa provides an immediate reason to assess bat activity and diversity, with the expectation of developing measures to mitigate for negative impacts. The overall aim of this thesis was contribute to an understanding of the drivers of bat activity, relevant to wind turbines, and to determine what factors (exogenous – environmental, or endogenous – intrinsic physiological processes) contributed to observed bat activity patterns, at the Metrowind Van Stadens Wind Farm in the Eastern Cape of South Africa. A combination of active (mist netting) and passive (acoustic) bat monitoring techniques were used to determine free-ranging bat activity patterns (Chapter 3). A total of 889 bat passes were recorded over 323 detector nights from the beginning of May 2012 to the end of December 2012. The Cape serotine bat (82 per cent) and the Egyptian free-tailed bat (97 per cent) made up the majority of all bat passes recorded on site. Large variations in bat activity per month and per hour were apparent, with bat activity peaking in May 2012 and during the first few hours after sunset (18:00-23:00). Patterns in nightly, free-ranging bat activity at the site were modelled against various environmental conditions. Month, temperature, wind speed and an interaction between month and rainfall were the most significant predictors of bat activity, explaining 80 per cent of the variation observed on free-ranging bat activity patterns. A total of eight Cape serotine bats (Table 4.1.) were caught in mist nets on site and changes in the resting metabolic rate (RMR) of torpid (n = 6), and normothermic (n = 2) bats, over a 24 hr period, were measured and used to predict free-ranging Cape serotine bat activity (Chapter 4). Cape serotine bats showed a high proclivity for torpor in the laboratory and peaks in RMR were observed at 18:00 (0.89 ± 0.95 VO2 mℓ.g-1.hr-1) and again from 20:00-21:00 (0.89 ± 0.91 VO2 mℓ.g-1.hr-1). Peaks in RMR of torpid individuals coincided with peaks in the average hourly free-ranging activity of the Cape serotine bat, and RMR explained 33 per cent of the variation and was a good predictor of free-ranging bat activity (R2 = 0.2914). This study showed that both exogenous (Chapter 3) and endogenous (Chapter 4) factors drive bat activity in the wild. Although this dissertation was not intended for wind turbine management, the information presented on the biology and activity of bats is important for managing interactions between bats and wind turbines. By determining what factors influence bat activity, we are able to predict when bats will be most active and thus can develop mitigation measures to reduce the potential impacts that wind turbines will have on the bat community. In order to conserve bats and reduce potential bat fatalities from occurring at the site, mitigation measures should be concentrated to those times when bats are most active (May and during the first few hours after sunset – 18:00 to 22:00).
- Full Text:
- Date Issued: 2014
- Authors: Thwaits, Tiffany Edan
- Date: 2014
- Subjects: Bats -- Behavior -- Climatic factors -- South Africa , Bats -- Ecology -- South Africa -- Eastern Cape , Wind power -- Environmental aspects
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10726 , http://hdl.handle.net/10948/d1020970
- Description: The increasing number of proposed wind farm developments in South Africa provides an immediate reason to assess bat activity and diversity, with the expectation of developing measures to mitigate for negative impacts. The overall aim of this thesis was contribute to an understanding of the drivers of bat activity, relevant to wind turbines, and to determine what factors (exogenous – environmental, or endogenous – intrinsic physiological processes) contributed to observed bat activity patterns, at the Metrowind Van Stadens Wind Farm in the Eastern Cape of South Africa. A combination of active (mist netting) and passive (acoustic) bat monitoring techniques were used to determine free-ranging bat activity patterns (Chapter 3). A total of 889 bat passes were recorded over 323 detector nights from the beginning of May 2012 to the end of December 2012. The Cape serotine bat (82 per cent) and the Egyptian free-tailed bat (97 per cent) made up the majority of all bat passes recorded on site. Large variations in bat activity per month and per hour were apparent, with bat activity peaking in May 2012 and during the first few hours after sunset (18:00-23:00). Patterns in nightly, free-ranging bat activity at the site were modelled against various environmental conditions. Month, temperature, wind speed and an interaction between month and rainfall were the most significant predictors of bat activity, explaining 80 per cent of the variation observed on free-ranging bat activity patterns. A total of eight Cape serotine bats (Table 4.1.) were caught in mist nets on site and changes in the resting metabolic rate (RMR) of torpid (n = 6), and normothermic (n = 2) bats, over a 24 hr period, were measured and used to predict free-ranging Cape serotine bat activity (Chapter 4). Cape serotine bats showed a high proclivity for torpor in the laboratory and peaks in RMR were observed at 18:00 (0.89 ± 0.95 VO2 mℓ.g-1.hr-1) and again from 20:00-21:00 (0.89 ± 0.91 VO2 mℓ.g-1.hr-1). Peaks in RMR of torpid individuals coincided with peaks in the average hourly free-ranging activity of the Cape serotine bat, and RMR explained 33 per cent of the variation and was a good predictor of free-ranging bat activity (R2 = 0.2914). This study showed that both exogenous (Chapter 3) and endogenous (Chapter 4) factors drive bat activity in the wild. Although this dissertation was not intended for wind turbine management, the information presented on the biology and activity of bats is important for managing interactions between bats and wind turbines. By determining what factors influence bat activity, we are able to predict when bats will be most active and thus can develop mitigation measures to reduce the potential impacts that wind turbines will have on the bat community. In order to conserve bats and reduce potential bat fatalities from occurring at the site, mitigation measures should be concentrated to those times when bats are most active (May and during the first few hours after sunset – 18:00 to 22:00).
- Full Text:
- Date Issued: 2014
Developing of a supply chain framework for civil engineering SMME's within the Nelson Mandela Bay Municipality
- Authors: Timotheus, Francois
- Date: 2014
- Subjects: Business logistics -- South Africa -- Nelson Mandela Bay Municipality Small business -- South Africa -- Nelson Mandela Bay Municipality
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/11242 , vital:26901
- Description: A lot of SMME development initiatives have been subsidised from the funds accumulated from taxpayers. In the promotion of sustainability and growth of SMMEs within developing countries particularly within the BRICS, South Africa is lagging despite its efforts over the past 17 years. According to STATS SA, SA’s unemployment rate for 2011 was between 24-36% and economic growth was 3.1%, the Eastern Cape Province is the poorest province within SA and therefore residence within the province is looking at start-up businesses to better their economic situation. The NMBM economic growth and employment is driven largely by its Integrated Development Plan (IDP) 2013/2014. Aims and objectives:To develop a supply chain management policy that addresses the challenges faced by infrastructure officials, supply chain management practitioners and ward councillors with regards to SMME engagement; and, Investigating the strengths, weaknesses and effectiveness of the current supply chain management policy employed within Nelson Mandela Bay Municipality with regards to SMME engagement. Research methodology: A questionnaire was used in this study to conduct quantitative research; the questionnaire was also used as a data collection tool. Valuable information was gathered from SMMEs residing in the Nelson Mandela Bay Municipal area who operate in the civil engineering field. These SMMEs formed the core research sample. Results: The findings suggest that the current supply chain management (SCM) policy of the Nelson Mandela Bay Municipality (NMBM) does not adequately address the challenges encountered by SMMEs. This suggests the SCM policy is inadequate and the policy must be amended to address its short falls:There is a need for a contractor development programme in the NMBM to assist the Potentially Emerging (PE) contractors within its boundaries;The NMBM is regulating the SMME market for competitiveness to some extent with its SCM policy;Even though the market is being regulated for competitiveness, it is not regulated with regards to new entries into the market; There is a need for the NMBM to provide business development services to SMME’s within its boundaries; The majority of SMME’s believed that there is no gender discrimination within the banking sector;The NMBM is an efficient government institution when it comes to settling their debt in a timely manner;The NMBM must appoint a committee to address the problems faced by SMME’s within its boundaries;South Africa’s National Credit Act (NCA) prevents SMME’s from acquiring an uncontrollable amount of debt. Conclusion: SMME’s within the NMBM enjoy a healthy credit record; these SMME’s also pay their suppliers in a timely fashion. Employees of these SMME’s are adequately compensated for their services. Some SMME’s service the equipment regularly and some do not. Some SMME’s are able to cover their overheads from the projects they undertake and some are not. SMME’s residing in the NMBM have experienced a growth in their business over the last financial year, even though they have not received substantial work over this period. The quality of the end product produced by some SMME’s meets the standard required by the NMBM. Recommendations: To address the development needs of the SMME’s the SCM policy needs to be amended to provide business development services and off-the-job training. To address the access to finance needs of the SMME’s the SCM policy needs to be amended to assist SMME’s in acquiring start-up capital, getting a reduced interest rate and creating work opportunities through micro-financing.
- Full Text:
- Date Issued: 2014
- Authors: Timotheus, Francois
- Date: 2014
- Subjects: Business logistics -- South Africa -- Nelson Mandela Bay Municipality Small business -- South Africa -- Nelson Mandela Bay Municipality
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/11242 , vital:26901
- Description: A lot of SMME development initiatives have been subsidised from the funds accumulated from taxpayers. In the promotion of sustainability and growth of SMMEs within developing countries particularly within the BRICS, South Africa is lagging despite its efforts over the past 17 years. According to STATS SA, SA’s unemployment rate for 2011 was between 24-36% and economic growth was 3.1%, the Eastern Cape Province is the poorest province within SA and therefore residence within the province is looking at start-up businesses to better their economic situation. The NMBM economic growth and employment is driven largely by its Integrated Development Plan (IDP) 2013/2014. Aims and objectives:To develop a supply chain management policy that addresses the challenges faced by infrastructure officials, supply chain management practitioners and ward councillors with regards to SMME engagement; and, Investigating the strengths, weaknesses and effectiveness of the current supply chain management policy employed within Nelson Mandela Bay Municipality with regards to SMME engagement. Research methodology: A questionnaire was used in this study to conduct quantitative research; the questionnaire was also used as a data collection tool. Valuable information was gathered from SMMEs residing in the Nelson Mandela Bay Municipal area who operate in the civil engineering field. These SMMEs formed the core research sample. Results: The findings suggest that the current supply chain management (SCM) policy of the Nelson Mandela Bay Municipality (NMBM) does not adequately address the challenges encountered by SMMEs. This suggests the SCM policy is inadequate and the policy must be amended to address its short falls:There is a need for a contractor development programme in the NMBM to assist the Potentially Emerging (PE) contractors within its boundaries;The NMBM is regulating the SMME market for competitiveness to some extent with its SCM policy;Even though the market is being regulated for competitiveness, it is not regulated with regards to new entries into the market; There is a need for the NMBM to provide business development services to SMME’s within its boundaries; The majority of SMME’s believed that there is no gender discrimination within the banking sector;The NMBM is an efficient government institution when it comes to settling their debt in a timely manner;The NMBM must appoint a committee to address the problems faced by SMME’s within its boundaries;South Africa’s National Credit Act (NCA) prevents SMME’s from acquiring an uncontrollable amount of debt. Conclusion: SMME’s within the NMBM enjoy a healthy credit record; these SMME’s also pay their suppliers in a timely fashion. Employees of these SMME’s are adequately compensated for their services. Some SMME’s service the equipment regularly and some do not. Some SMME’s are able to cover their overheads from the projects they undertake and some are not. SMME’s residing in the NMBM have experienced a growth in their business over the last financial year, even though they have not received substantial work over this period. The quality of the end product produced by some SMME’s meets the standard required by the NMBM. Recommendations: To address the development needs of the SMME’s the SCM policy needs to be amended to provide business development services and off-the-job training. To address the access to finance needs of the SMME’s the SCM policy needs to be amended to assist SMME’s in acquiring start-up capital, getting a reduced interest rate and creating work opportunities through micro-financing.
- Full Text:
- Date Issued: 2014
Development and assessment of sustained release stavudine loaded microparticles
- Authors: Zindove, Chiedza Cathrine
- Date: 2014
- Language: English
- Type: text , Thesis , Masters , MPharm
- Identifier: http://hdl.handle.net/10962/54722 , vital:26603
- Description:
Stavudine (D4T) has been used as first line treatment for HIV/AIDS and is part of highly active anti retroviral treatment (HAART). It is an affordable medicine and its use is beneficial in resource limited settings. However D4T exhibits dose dependent side effects that may lead to non-adherence in patients. This study was undertaken to formulate, develop and manufacture a dosage form that could reduce dose dependent side effects by decreasing the dose of D4T but still exhibit antiretroviral (ARV) activity. The use of sustained release (SR) formulations of D4T that ensure constant levels of the D4T in the body would not only optimize therapy but also reduce the incidence of side effects thereby increasing patient adherence. SR microparticles containing 30mg D4T were manufactured and loaded into size 3 hard gelatine capsules prior to analysis. The D4T microparticles were manufactured by microencapsulation using non-aqueous oil-in-oil solvent evaporation approach. D4T-excipient, excipient-excipient interactions and D4T purity were assessed using Infrared Spectroscopy (IR), Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). Copolymers synthesized from acrylic and methacrylic acid esters viz., Eudragit® RSPO and S100 were used as rate retardant materials and the effect of microcrystalline cellulose (Avicel® PH102) on the microparticles was also investigated. Magnesium stearate was used as a droplet stabilizer and n-hexane was added to harden the microspheres formed in a liquid paraffin continuous phase. The microparticles were optimized using a Box Behnken design and Response Surface Methodology (RSM). The microparticles were characterized in terms of their flow properties and encapsulation efficiency (% EE), in addition to visualization of the surface morphology with Scanning Electron Microscopy. In vitro D4T release studies were performed using USP Apparatus III in media of different pH and the samples were analysed using a validated High Performance Liquid Chromatographic (HPLC) method with ultraviolet (UV) detection that had been developed and optimized using a Central Composite Design (CCD). The method was validated according to ICH guidelines. The IR spectra and DSC thermographs revealed that D4T exhibited thermal stability and there was no evidence of D4T-excipient and excipient-excipient interactions. The microparticles that were produced were white, free flowing and were obtained in a high yield with high encapsulation efficiency. Scanning Electron Microscopy studies revealed that the microparticles were spherical and porous in nature. In vitro D4T release extended to 12 hours and the mechanism of release was established using model dependent methods by fitting the data to a Zero order, First order, Higuchi and Hixson Crowell model. It was observed that the mechanism of D4T release was diffusion-controlled and that the data was best fitted to the Higuchi model with correlation coefficients > 0.9. The release mechanism was confirmed using the Korsmeyer-Peppas model that revealed that most of the formulations exhibited anomalous transport kinetics with the release exponent, n, ranging from 0.5
- Full Text:
- Date Issued: 2014
- Authors: Zindove, Chiedza Cathrine
- Date: 2014
- Language: English
- Type: text , Thesis , Masters , MPharm
- Identifier: http://hdl.handle.net/10962/54722 , vital:26603
- Description:
Stavudine (D4T) has been used as first line treatment for HIV/AIDS and is part of highly active anti retroviral treatment (HAART). It is an affordable medicine and its use is beneficial in resource limited settings. However D4T exhibits dose dependent side effects that may lead to non-adherence in patients. This study was undertaken to formulate, develop and manufacture a dosage form that could reduce dose dependent side effects by decreasing the dose of D4T but still exhibit antiretroviral (ARV) activity. The use of sustained release (SR) formulations of D4T that ensure constant levels of the D4T in the body would not only optimize therapy but also reduce the incidence of side effects thereby increasing patient adherence. SR microparticles containing 30mg D4T were manufactured and loaded into size 3 hard gelatine capsules prior to analysis. The D4T microparticles were manufactured by microencapsulation using non-aqueous oil-in-oil solvent evaporation approach. D4T-excipient, excipient-excipient interactions and D4T purity were assessed using Infrared Spectroscopy (IR), Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). Copolymers synthesized from acrylic and methacrylic acid esters viz., Eudragit® RSPO and S100 were used as rate retardant materials and the effect of microcrystalline cellulose (Avicel® PH102) on the microparticles was also investigated. Magnesium stearate was used as a droplet stabilizer and n-hexane was added to harden the microspheres formed in a liquid paraffin continuous phase. The microparticles were optimized using a Box Behnken design and Response Surface Methodology (RSM). The microparticles were characterized in terms of their flow properties and encapsulation efficiency (% EE), in addition to visualization of the surface morphology with Scanning Electron Microscopy. In vitro D4T release studies were performed using USP Apparatus III in media of different pH and the samples were analysed using a validated High Performance Liquid Chromatographic (HPLC) method with ultraviolet (UV) detection that had been developed and optimized using a Central Composite Design (CCD). The method was validated according to ICH guidelines. The IR spectra and DSC thermographs revealed that D4T exhibited thermal stability and there was no evidence of D4T-excipient and excipient-excipient interactions. The microparticles that were produced were white, free flowing and were obtained in a high yield with high encapsulation efficiency. Scanning Electron Microscopy studies revealed that the microparticles were spherical and porous in nature. In vitro D4T release extended to 12 hours and the mechanism of release was established using model dependent methods by fitting the data to a Zero order, First order, Higuchi and Hixson Crowell model. It was observed that the mechanism of D4T release was diffusion-controlled and that the data was best fitted to the Higuchi model with correlation coefficients > 0.9. The release mechanism was confirmed using the Korsmeyer-Peppas model that revealed that most of the formulations exhibited anomalous transport kinetics with the release exponent, n, ranging from 0.5
- Full Text:
- Date Issued: 2014
Development and evaluation of pictograms on medication labels for patients with limited literacy skills in a culturally diverse multiethnic population:
- Kheir, Nadir, Awaisu, Ahmed, Radoui, Amina, El Badawi, Aya, Jean, Linda, Dowse, Roslind
- Authors: Kheir, Nadir , Awaisu, Ahmed , Radoui, Amina , El Badawi, Aya , Jean, Linda , Dowse, Roslind
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156720 , vital:40041 , https://doi.org/10.1016/j.sapharm.2013.11.003
- Description: Much of the migrant workforce in Qatar is of low literacy level and does not understand Arabic or English, presenting a significant challenge to health care professionals. Medicine labels are typically in Arabic and English and are therefore poorly understood by these migrant workers. To develop pictograms illustrating selected medicine label instructions and to evaluate comprehension of the pictograms or conventional text supported with verbal instructions in foreign workers with low literacy skills.
- Full Text:
- Date Issued: 2014
- Authors: Kheir, Nadir , Awaisu, Ahmed , Radoui, Amina , El Badawi, Aya , Jean, Linda , Dowse, Roslind
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156720 , vital:40041 , https://doi.org/10.1016/j.sapharm.2013.11.003
- Description: Much of the migrant workforce in Qatar is of low literacy level and does not understand Arabic or English, presenting a significant challenge to health care professionals. Medicine labels are typically in Arabic and English and are therefore poorly understood by these migrant workers. To develop pictograms illustrating selected medicine label instructions and to evaluate comprehension of the pictograms or conventional text supported with verbal instructions in foreign workers with low literacy skills.
- Full Text:
- Date Issued: 2014
Development finance in small and medium enterprises in Matjhabeng Municipality
- Babalola, Oluwanifesimi Omolade
- Authors: Babalola, Oluwanifesimi Omolade
- Date: 2014
- Subjects: Business enterprises -- South Africa -- Finance , Economic development -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:9187 , http://hdl.handle.net/10948/d1020215
- Description: It has been generally accepted within the developed and developing countries of the world that SMES contributes significantly to employment creation as the world population increases and that it also contributes to the economic growth of the areas they are situated in. Finance is the blood (life) of any business, for a business to be successful it needs steady successful access to funds and post financial support which leads to actualization of ideas, leads to investment and expansion, improves access to market amongst others. This is why the impact of development finance can never be over emphasized. The aims of the study are: To understand the extent to which small and medium businesses are supported through the availability of financial assistance in Matjabeng Municipality. To establish the survival rates of businesses that has been funded and or supported and whether they are or not sustainable. In achieving the aims and objectives of the research, the researcher looked at development funds both from the supply side and the demand side. The supply side which involved semi structured interviews with consultants of government parastatals (the FDC and DETEA) who are involved in financing Small Medium Enterprises in Matjhabeng municipality. The demand side involved administering of questionnaires to Entrepreneurs in the municipality who are registered with the Local Economic Department (LED), which led to the acceptance of the hypothesis of the research that development finance actually helps in the growth of small medium enterprises but in conjunction with post financial support such as bookkeeping, accounting, monitoring and evaluation. The researcher also discovered some findings amongst others which includes: The most effective ways entrepreneurs heard about funding in the municipality are through the media and word of mouth. Most of the entrepreneurs that received some type of funding are startups. More entrepreneurs that had access to funds also got some post financial business support. Financial assistance to entrepreneurs yielded improvements after respondents received financial assistance, the range of goods offered was improved and more jobs were created, entrepreneurs were able to obtain better business premises either by renting or buying and entrepreneurs had access to better equipment. Some of the recommendations of this study includes; The municipal government should help small and medium enterprises in the municipality by linking them to new markets. Effective monitoring and evaluation systems should be put in place by development funders and non-financial support services. Entrepreneurial skills development should be provided by the public and private agencies by organizing workshops for aspiring entrepreneurs in order to expose them to business opportunities that are sustainable and viable.
- Full Text:
- Date Issued: 2014
- Authors: Babalola, Oluwanifesimi Omolade
- Date: 2014
- Subjects: Business enterprises -- South Africa -- Finance , Economic development -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:9187 , http://hdl.handle.net/10948/d1020215
- Description: It has been generally accepted within the developed and developing countries of the world that SMES contributes significantly to employment creation as the world population increases and that it also contributes to the economic growth of the areas they are situated in. Finance is the blood (life) of any business, for a business to be successful it needs steady successful access to funds and post financial support which leads to actualization of ideas, leads to investment and expansion, improves access to market amongst others. This is why the impact of development finance can never be over emphasized. The aims of the study are: To understand the extent to which small and medium businesses are supported through the availability of financial assistance in Matjabeng Municipality. To establish the survival rates of businesses that has been funded and or supported and whether they are or not sustainable. In achieving the aims and objectives of the research, the researcher looked at development funds both from the supply side and the demand side. The supply side which involved semi structured interviews with consultants of government parastatals (the FDC and DETEA) who are involved in financing Small Medium Enterprises in Matjhabeng municipality. The demand side involved administering of questionnaires to Entrepreneurs in the municipality who are registered with the Local Economic Department (LED), which led to the acceptance of the hypothesis of the research that development finance actually helps in the growth of small medium enterprises but in conjunction with post financial support such as bookkeeping, accounting, monitoring and evaluation. The researcher also discovered some findings amongst others which includes: The most effective ways entrepreneurs heard about funding in the municipality are through the media and word of mouth. Most of the entrepreneurs that received some type of funding are startups. More entrepreneurs that had access to funds also got some post financial business support. Financial assistance to entrepreneurs yielded improvements after respondents received financial assistance, the range of goods offered was improved and more jobs were created, entrepreneurs were able to obtain better business premises either by renting or buying and entrepreneurs had access to better equipment. Some of the recommendations of this study includes; The municipal government should help small and medium enterprises in the municipality by linking them to new markets. Effective monitoring and evaluation systems should be put in place by development funders and non-financial support services. Entrepreneurial skills development should be provided by the public and private agencies by organizing workshops for aspiring entrepreneurs in order to expose them to business opportunities that are sustainable and viable.
- Full Text:
- Date Issued: 2014
Development NGOs : understanding participatory methods, accountability and effectiveness of World Vision in Zimbabwe with specific reference to Umzingwane District.
- Authors: Knight, Kayla Christine
- Date: 2014
- Subjects: World Vision International , Non-governmental organizations -- Zimbabwe , Non-governmental organizations -- Evaluation , Economic assistance -- Zimbabwe , Economic development -- Zimbabwe , Zimbabwe -- Politics and government -- 1980- , Zimbabwe -- Social conditions -- 1980- , Zimbabwe -- Economic conditions -- 1980-
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3376 , http://hdl.handle.net/10962/d1013135
- Description: Non-governmental Organizations (NGOs) have occupied a prominent role in the development of rural Zimbabwe since the time of its independence in 1980. NGO work in Zimbabwe currently takes place within the context of a tense and fluid political climate, an economy struggling to recover from crisis, international skepticism toward long-term donor investment in development, and global expectations about the methodologies and accountability measures carried out in intervention-based development work. In the light of the participatory methodologies and empowerment-based development frameworks that dominate the current global expectations for work within the NGO sector, this thesis focuses on the work of one particular NGO working in Zimbabwe, namely, World Vision. The main objective of the thesis is to understand and explain the participatory methods, accountability and effectiveness of World Vision in Zimbabwe (with particular reference to Umzingwane District) and, in doing so, to deepen the theoretical understanding of NGOs as constituting a particular organizational form. World Vision is a large-scale international NGO that has a pronounced presence in Zimbabwe and it is specifically active in Umzingwane District in Matabeleland South Province. The thesis argues that NGOs exist within a complex and tense condition entailing continuous responses to pressures from donors and states that structure their survival. Ultimately, in maneuvering through such pressures, NGOs tend to choose directions which best enable their own sustainability, often at the cost of the deep participatory forms that may heighten the legitimacy of their roles. World Vision Zimbabwe responds to donor trends, national and local expectations of the state and its own organizational expectations by building local government capacity in order to maintain the longevity and measureable outputs of its projects. In doing so, it redefines the concept of participation in pursuing efficient and practical approaches to ‘getting things done’. This compromises deep participatory methodologies and, in essence, alters the practices involved in participatory forms in order to maintain World Vision’s own organizational sustainability and presence in Zimbabwe.
- Full Text:
- Date Issued: 2014
- Authors: Knight, Kayla Christine
- Date: 2014
- Subjects: World Vision International , Non-governmental organizations -- Zimbabwe , Non-governmental organizations -- Evaluation , Economic assistance -- Zimbabwe , Economic development -- Zimbabwe , Zimbabwe -- Politics and government -- 1980- , Zimbabwe -- Social conditions -- 1980- , Zimbabwe -- Economic conditions -- 1980-
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3376 , http://hdl.handle.net/10962/d1013135
- Description: Non-governmental Organizations (NGOs) have occupied a prominent role in the development of rural Zimbabwe since the time of its independence in 1980. NGO work in Zimbabwe currently takes place within the context of a tense and fluid political climate, an economy struggling to recover from crisis, international skepticism toward long-term donor investment in development, and global expectations about the methodologies and accountability measures carried out in intervention-based development work. In the light of the participatory methodologies and empowerment-based development frameworks that dominate the current global expectations for work within the NGO sector, this thesis focuses on the work of one particular NGO working in Zimbabwe, namely, World Vision. The main objective of the thesis is to understand and explain the participatory methods, accountability and effectiveness of World Vision in Zimbabwe (with particular reference to Umzingwane District) and, in doing so, to deepen the theoretical understanding of NGOs as constituting a particular organizational form. World Vision is a large-scale international NGO that has a pronounced presence in Zimbabwe and it is specifically active in Umzingwane District in Matabeleland South Province. The thesis argues that NGOs exist within a complex and tense condition entailing continuous responses to pressures from donors and states that structure their survival. Ultimately, in maneuvering through such pressures, NGOs tend to choose directions which best enable their own sustainability, often at the cost of the deep participatory forms that may heighten the legitimacy of their roles. World Vision Zimbabwe responds to donor trends, national and local expectations of the state and its own organizational expectations by building local government capacity in order to maintain the longevity and measureable outputs of its projects. In doing so, it redefines the concept of participation in pursuing efficient and practical approaches to ‘getting things done’. This compromises deep participatory methodologies and, in essence, alters the practices involved in participatory forms in order to maintain World Vision’s own organizational sustainability and presence in Zimbabwe.
- Full Text:
- Date Issued: 2014
Development of a bench scale single batch biomass to liquid fuel facility
- Authors: Zhang, Yusheng
- Date: 2014
- Subjects: Biomass energy , Renewable energy sources , Energy conversion , Electric power production
- Language: English
- Type: Thesis , Masters , MSc (Chemistry)
- Identifier: http://hdl.handle.net/10353/811 , vital:26499 , Biomass energy , Renewable energy sources , Energy conversion , Electric power production
- Description: The research described in this dissertation was motivated by the global demand for energy that is not dependent on coal, oil, natural gas and other non-renewable fossil fuels. The technology used in this project is related to the use of biomass to produce a viable alternative to conventional sources of fuel. A bench scale biomass to liquid (BTL) facility was built and tested. This produced results confirming the feasibility of the BTL process. The findings of the pilot study outlined in this dissertation justified the conclusion that the next step will be to expand the capacity and productivity of the BTL pilot plant to an industrial scale. Biomass comes from a variety of renewable sources that are readily available. In this case, the material used in the fixed bed biomass gasification facility to generate wood gas was agricultural and forestry waste, such as straw and wood chips. The gasifier had the capacity to produce up to 10 cubic metres/hr of gas with a carbon monoxide and hydrogen content of between 20–40% by volume, when it was operated at ambient pressure and with air as the oxidizer. The gas, produced at a temperature above 700º C, was cooled in a quench/water scrubber in order to remove most of the mechanical impurities (tars and water-soluble inorganic particles), condensed and dried with corn cobs before being compressed in cylinders at over 100 bar (g) for use in the Fischer-Tropsch Synthesis (FTS). The syngas was subjected further to a series of refining processes which included removal of sulphur and oxygen. The sulphur removal technology chosen entailed applying modified activated carbon to adsorb H2S with the help of hydrolysis in order to convert organic sulphur impurities into H2S which reduced the sulphur content of the gas to less than 5 ppbv. Supported cobalt catalyst (100 grams), were loaded into a single-tube fixed bed FT reactor with an inner diameter of 50 mm. The reactor was fitted with a heating jacket through which, heated oil ran to cool the reactor during a normal reaction occurring at < 250 ºC, while nitrogen was used in the heating jacket during reduction, which occurred at temperatures up ~ 350 ºC. The FTS reaction was carried out at different pressures and temperatures. Liquid and wax products were produced from the facility. The properties of the liquid and solid hydrocarbons produced were found to be the same as FT products from other feed stocks, such as natural gas and coal.
- Full Text:
- Date Issued: 2014
- Authors: Zhang, Yusheng
- Date: 2014
- Subjects: Biomass energy , Renewable energy sources , Energy conversion , Electric power production
- Language: English
- Type: Thesis , Masters , MSc (Chemistry)
- Identifier: http://hdl.handle.net/10353/811 , vital:26499 , Biomass energy , Renewable energy sources , Energy conversion , Electric power production
- Description: The research described in this dissertation was motivated by the global demand for energy that is not dependent on coal, oil, natural gas and other non-renewable fossil fuels. The technology used in this project is related to the use of biomass to produce a viable alternative to conventional sources of fuel. A bench scale biomass to liquid (BTL) facility was built and tested. This produced results confirming the feasibility of the BTL process. The findings of the pilot study outlined in this dissertation justified the conclusion that the next step will be to expand the capacity and productivity of the BTL pilot plant to an industrial scale. Biomass comes from a variety of renewable sources that are readily available. In this case, the material used in the fixed bed biomass gasification facility to generate wood gas was agricultural and forestry waste, such as straw and wood chips. The gasifier had the capacity to produce up to 10 cubic metres/hr of gas with a carbon monoxide and hydrogen content of between 20–40% by volume, when it was operated at ambient pressure and with air as the oxidizer. The gas, produced at a temperature above 700º C, was cooled in a quench/water scrubber in order to remove most of the mechanical impurities (tars and water-soluble inorganic particles), condensed and dried with corn cobs before being compressed in cylinders at over 100 bar (g) for use in the Fischer-Tropsch Synthesis (FTS). The syngas was subjected further to a series of refining processes which included removal of sulphur and oxygen. The sulphur removal technology chosen entailed applying modified activated carbon to adsorb H2S with the help of hydrolysis in order to convert organic sulphur impurities into H2S which reduced the sulphur content of the gas to less than 5 ppbv. Supported cobalt catalyst (100 grams), were loaded into a single-tube fixed bed FT reactor with an inner diameter of 50 mm. The reactor was fitted with a heating jacket through which, heated oil ran to cool the reactor during a normal reaction occurring at < 250 ºC, while nitrogen was used in the heating jacket during reduction, which occurred at temperatures up ~ 350 ºC. The FTS reaction was carried out at different pressures and temperatures. Liquid and wax products were produced from the facility. The properties of the liquid and solid hydrocarbons produced were found to be the same as FT products from other feed stocks, such as natural gas and coal.
- Full Text:
- Date Issued: 2014
Development of a bulbine frutescens and carpobrotus edulis cream in collaboration with african traditional healers of the Nelson Mandela Metropole
- Authors: Keele, Mbali Zamathiyane
- Date: 2014
- Subjects: Drug development -- South Africa -- Port Elizabeth , Healers -- South Africa -- Port Elizabeth , Traditional medicine -- South Africa -- Port Elizabeth , Physicians -- Health -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10358 , http://hdl.handle.net/10948/d1021016
- Description: Collaborations between researchers and African traditional healers on medicinal plants need to go beyond the flow of information from African traditional healers to researchers. Mutual beneficiation wherein African traditional healers reap rewards due to the information they possess is necessary and has been legislated in South Africa. The manner in which such beneficiation occurs and how it will be distributed should be subject to negotiation between (a) the researchers and holders of indigenous knowledge and (b) among holders of indigenous knowledge themselves. Beneficiation can be in the form of access to information, monetary or through shares in commercialised products, amongst others. African traditional healers involved in the collaboration with researchers of the Department of Biochemistry and Microbiology and the Department of Pharmacy at the Nelson Mandela Metropolitan University beneficiated by having access to knowledge and medicinal plants cultivated in the medicinal garden. Beneficiation was expected to extend to monetary gains from the sale of sewn garments and plants from a medicinal plants nursery which was to be developed and from a herbal topical product which was also to be developed. The aim of this research project was to develop a wound healing herbal cream consisting of Bulbine frutescens and Carpobrotus edulis as active ingredients. B. frutescens demonstrated better wound closure properties when compared to C. edulis and the combined extracts. The scratch assay wound was completely closed after 24 hours at B. frutescens concentrations of 5 μg/ml and 10 μg/ml. B. frutescens was more toxic to 3t3-L1 cells than C. edulis, but it was less toxic than the combined extracts. None of the extracts were toxic to Vero cells and the combined extracts significantly promoted their proliferation. Antibacterial activity of all the extracts was low. C. edulis showed antiviral activity against human herpes simplex virus 1 at 62.5, 125 and 250 μg/ml, while the combined extracts were active at 250 μg/ml. The combined extracts exhibited synergistic antioxidant activity. A reverse phase, gradient, high performance liquid chromatography method was developed and validated and used to conduct quality control tests on the extracts and the finished product. It was concluded that the use of whole chromatographic data instead of common peaks data is best for analysis of medicinal plants. The cream that was developed used buffered cream as the base and was stable at 25 °C/65 percent RH for one month with regard to organoleptic and rheological properties and microbial preservation.
- Full Text:
- Date Issued: 2014
- Authors: Keele, Mbali Zamathiyane
- Date: 2014
- Subjects: Drug development -- South Africa -- Port Elizabeth , Healers -- South Africa -- Port Elizabeth , Traditional medicine -- South Africa -- Port Elizabeth , Physicians -- Health -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10358 , http://hdl.handle.net/10948/d1021016
- Description: Collaborations between researchers and African traditional healers on medicinal plants need to go beyond the flow of information from African traditional healers to researchers. Mutual beneficiation wherein African traditional healers reap rewards due to the information they possess is necessary and has been legislated in South Africa. The manner in which such beneficiation occurs and how it will be distributed should be subject to negotiation between (a) the researchers and holders of indigenous knowledge and (b) among holders of indigenous knowledge themselves. Beneficiation can be in the form of access to information, monetary or through shares in commercialised products, amongst others. African traditional healers involved in the collaboration with researchers of the Department of Biochemistry and Microbiology and the Department of Pharmacy at the Nelson Mandela Metropolitan University beneficiated by having access to knowledge and medicinal plants cultivated in the medicinal garden. Beneficiation was expected to extend to monetary gains from the sale of sewn garments and plants from a medicinal plants nursery which was to be developed and from a herbal topical product which was also to be developed. The aim of this research project was to develop a wound healing herbal cream consisting of Bulbine frutescens and Carpobrotus edulis as active ingredients. B. frutescens demonstrated better wound closure properties when compared to C. edulis and the combined extracts. The scratch assay wound was completely closed after 24 hours at B. frutescens concentrations of 5 μg/ml and 10 μg/ml. B. frutescens was more toxic to 3t3-L1 cells than C. edulis, but it was less toxic than the combined extracts. None of the extracts were toxic to Vero cells and the combined extracts significantly promoted their proliferation. Antibacterial activity of all the extracts was low. C. edulis showed antiviral activity against human herpes simplex virus 1 at 62.5, 125 and 250 μg/ml, while the combined extracts were active at 250 μg/ml. The combined extracts exhibited synergistic antioxidant activity. A reverse phase, gradient, high performance liquid chromatography method was developed and validated and used to conduct quality control tests on the extracts and the finished product. It was concluded that the use of whole chromatographic data instead of common peaks data is best for analysis of medicinal plants. The cream that was developed used buffered cream as the base and was stable at 25 °C/65 percent RH for one month with regard to organoleptic and rheological properties and microbial preservation.
- Full Text:
- Date Issued: 2014
Development of a mechatronic transmission control system for the drivetrain of the K71 project
- Authors: Nortemann, Alexander
- Date: 2014
- Subjects: Motor vehicles -- Transmission devices , Automobiles -- Power trains , Automobile driving -- Shifting gear
- Language: English
- Type: Thesis , Masters , MEngineering (Mechatronics)
- Identifier: vital:9659
- Description: The tractive force has to be interrupted during a gear-shifting operation in a manual vehicle transmission, leading into a decrease of speed while changing gears during the acceleration process. Therefore in a racing application, the shifting time has to be as short as possible so that the required performance of a racing car can be achieved. The following dissertation describes the development of a transmission control system to enable gear changes within a manual gearbox, which was designed for the Formula Student racing series. Various solutions were developed on the basis of reviewed literature, technical data of components and experiences of Formula Student teams. Following this, a comparison of the concepts by means of a utility analysis identified the pneumatic actuation of selector forks to be the most suitable concept. This was mainly due to the expected shifting time, the weight, and its advantageous energy supply requirement. After the selection of the actuators and the position sensors, the system was implemented into the drivetrain to check the tment and the technical feasibility. To draw conclusions regarding the shifting time and to prove the functionality of the system, an open test bench was constructed. Additionally, the hardware and software had to be developed to enable the test run. After the manufacturing and assembling of the test bench, the optimal settings for the test run were determined. By comparing the achieved shifting time of alternative solutions, an improvement in the driving performance of a Formula Student race car is probable.
- Full Text:
- Date Issued: 2014
- Authors: Nortemann, Alexander
- Date: 2014
- Subjects: Motor vehicles -- Transmission devices , Automobiles -- Power trains , Automobile driving -- Shifting gear
- Language: English
- Type: Thesis , Masters , MEngineering (Mechatronics)
- Identifier: vital:9659
- Description: The tractive force has to be interrupted during a gear-shifting operation in a manual vehicle transmission, leading into a decrease of speed while changing gears during the acceleration process. Therefore in a racing application, the shifting time has to be as short as possible so that the required performance of a racing car can be achieved. The following dissertation describes the development of a transmission control system to enable gear changes within a manual gearbox, which was designed for the Formula Student racing series. Various solutions were developed on the basis of reviewed literature, technical data of components and experiences of Formula Student teams. Following this, a comparison of the concepts by means of a utility analysis identified the pneumatic actuation of selector forks to be the most suitable concept. This was mainly due to the expected shifting time, the weight, and its advantageous energy supply requirement. After the selection of the actuators and the position sensors, the system was implemented into the drivetrain to check the tment and the technical feasibility. To draw conclusions regarding the shifting time and to prove the functionality of the system, an open test bench was constructed. Additionally, the hardware and software had to be developed to enable the test run. After the manufacturing and assembling of the test bench, the optimal settings for the test run were determined. By comparing the achieved shifting time of alternative solutions, an improvement in the driving performance of a Formula Student race car is probable.
- Full Text:
- Date Issued: 2014
Development of a theoretical model of integrated reporting for Johannesburg Stock Exchange (JSE) listed companies
- Authors: Ncemane, Zuko
- Date: 2014
- Subjects: Corporation reports -- South Africa -- Johannesburg
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/11265 , vital:26903
- Description: Purpose – The purpose of this case study research was to develop a theoretical model of integrated reporting for Johannesburg Stock Exchange (JSE) listed companies. Design/Methodology/Approach – The goal of this case study research was to understand how and why integrated reports are prepared, to develop a theoretical model of integrated reporting for JSE listed companies through literature review and analysis of published integrated reports. In addition, to investigate the perceived success of integrated reporting by examining its requirements, objectives, enforceability and implications to the listed companies. Based on the above, to determine how companies fulfil the requirements of integrated reporting and what those requirements are. To determine by comparing published integrated reports of companies, similarities or comparability of the information published on integrated reports ascertaining the measurability of the success of the application of integrated reporting. Practical implications – This case study research provides a useful insight into drivers of integrated reporting. Limitations to the study – The lack of responses from industry experts contacted for interviews considered a limitation in validating the outcome of the study. Originality/Value – This case study research looks at the current adoption and application of integrated reporting by JSE listed companies.
- Full Text:
- Date Issued: 2014
- Authors: Ncemane, Zuko
- Date: 2014
- Subjects: Corporation reports -- South Africa -- Johannesburg
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/11265 , vital:26903
- Description: Purpose – The purpose of this case study research was to develop a theoretical model of integrated reporting for Johannesburg Stock Exchange (JSE) listed companies. Design/Methodology/Approach – The goal of this case study research was to understand how and why integrated reports are prepared, to develop a theoretical model of integrated reporting for JSE listed companies through literature review and analysis of published integrated reports. In addition, to investigate the perceived success of integrated reporting by examining its requirements, objectives, enforceability and implications to the listed companies. Based on the above, to determine how companies fulfil the requirements of integrated reporting and what those requirements are. To determine by comparing published integrated reports of companies, similarities or comparability of the information published on integrated reports ascertaining the measurability of the success of the application of integrated reporting. Practical implications – This case study research provides a useful insight into drivers of integrated reporting. Limitations to the study – The lack of responses from industry experts contacted for interviews considered a limitation in validating the outcome of the study. Originality/Value – This case study research looks at the current adoption and application of integrated reporting by JSE listed companies.
- Full Text:
- Date Issued: 2014
Development of an ionospheric map for Africa
- Authors: Ssessanga, Nicholas
- Date: 2014
- Subjects: Ionosondes Ionosphere Ionosphere -- Observations Ionosphere -- Research -- Africa Ionospheric electron density -- Africa Ionospheric critical frequencies
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5519 , http://hdl.handle.net/10962/d1011498
- Description: This thesis presents research pertaining to the development of an African Ionospheric Map (AIM). An ionospheric map is a computer program that is able to display spatial and temporal representations of ionospheric parameters such as, electron density and critical plasma frequencies, for every geographical location on the map. The purpose of this development was to make the most optimum use of all available data sources, namely ionosondes, satellites and models, and to implement error minimisation techniques in order to obtain the best result at any given location on the African continent. The focus was placed on the accurate estimation of three upper atmosphere parameters which are important for radio communications: critical frequency of the F2 layer (foF2), Total Electron Content (TEC) and the maximum usable frequency over a distance of 3000 km (M3000F2). The results show that AIM provided a more accurate estimation of the three parameters than the internationally recognised and recommended ionosphere model (IRI-2012) when used on its own. Therefore, the AIM is a more accurate solution than single independent data sources for applications requiring ionospheric mapping over the African continent.
- Full Text:
- Date Issued: 2014
- Authors: Ssessanga, Nicholas
- Date: 2014
- Subjects: Ionosondes Ionosphere Ionosphere -- Observations Ionosphere -- Research -- Africa Ionospheric electron density -- Africa Ionospheric critical frequencies
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5519 , http://hdl.handle.net/10962/d1011498
- Description: This thesis presents research pertaining to the development of an African Ionospheric Map (AIM). An ionospheric map is a computer program that is able to display spatial and temporal representations of ionospheric parameters such as, electron density and critical plasma frequencies, for every geographical location on the map. The purpose of this development was to make the most optimum use of all available data sources, namely ionosondes, satellites and models, and to implement error minimisation techniques in order to obtain the best result at any given location on the African continent. The focus was placed on the accurate estimation of three upper atmosphere parameters which are important for radio communications: critical frequency of the F2 layer (foF2), Total Electron Content (TEC) and the maximum usable frequency over a distance of 3000 km (M3000F2). The results show that AIM provided a more accurate estimation of the three parameters than the internationally recognised and recommended ionosphere model (IRI-2012) when used on its own. Therefore, the AIM is a more accurate solution than single independent data sources for applications requiring ionospheric mapping over the African continent.
- Full Text:
- Date Issued: 2014
Development of an M-commerce security framework
- Murufu, Mufudzi Anesu Chapman
- Authors: Murufu, Mufudzi Anesu Chapman
- Date: 2014
- Subjects: Mobile commerce , Telecommunication systems
- Language: English
- Type: Thesis , Masters , MSc (Computer Science)
- Identifier: http://hdl.handle.net/10353/833 , vital:26501 , Mobile commerce , Telecommunication systems
- Description: Research shows how M-Commerce has managed to find its way to previously inaccessible parts of the world as a major Information and Communication Technologies (ICT) tool for development due to widespread introduction of mobile phones in remote areas. M-Commerce has offered valuable advantages: anytime, anywhere, more personal, more location-aware, more context-aware, more age aware, always online and instant connectivity. But this is not without its problems, of which security is high on the list. The security issues span the whole M-Commerce spectrum, from the top to the bottom layer of the OSI network protocol stack, from machines to humans. This research proposes a threat-mitigation modular framework to help address the security issues lurking in M-Commerce systems being used by marginalised rural community members. The research commences with a literature survey carried out to establish security aspects related to M-Commerce and to determine requirements for a security framework. The framework classifies M-Commerce security threat-vulnerability-risks into four levels: human behaviour and mobile device interaction security, mobile device security, M-Commerce access channel security, wireless network access security. This is followed by a review of the supporting structures or related frameworks that the proposed framework could leverage to address security issues on M-Commerce systems as ICT4D initiatives. The proposed security framework based on the requirements discovered is then presented. As a proof-of-concept, a case study was undertaken at the Siyakhula Living Lab at Dwesa in the Eastern Cape province of South Africa in order to validate the components of the proposed framework. Following the application of the framework in a case study, it can be argued that the proposed security framework allows for secure transacting by marginalised users using M-Commerce initiatives. The security framework is therefore useful in addressing the identified security requirements of M-Commerce in ICT4D contexts.
- Full Text:
- Date Issued: 2014
- Authors: Murufu, Mufudzi Anesu Chapman
- Date: 2014
- Subjects: Mobile commerce , Telecommunication systems
- Language: English
- Type: Thesis , Masters , MSc (Computer Science)
- Identifier: http://hdl.handle.net/10353/833 , vital:26501 , Mobile commerce , Telecommunication systems
- Description: Research shows how M-Commerce has managed to find its way to previously inaccessible parts of the world as a major Information and Communication Technologies (ICT) tool for development due to widespread introduction of mobile phones in remote areas. M-Commerce has offered valuable advantages: anytime, anywhere, more personal, more location-aware, more context-aware, more age aware, always online and instant connectivity. But this is not without its problems, of which security is high on the list. The security issues span the whole M-Commerce spectrum, from the top to the bottom layer of the OSI network protocol stack, from machines to humans. This research proposes a threat-mitigation modular framework to help address the security issues lurking in M-Commerce systems being used by marginalised rural community members. The research commences with a literature survey carried out to establish security aspects related to M-Commerce and to determine requirements for a security framework. The framework classifies M-Commerce security threat-vulnerability-risks into four levels: human behaviour and mobile device interaction security, mobile device security, M-Commerce access channel security, wireless network access security. This is followed by a review of the supporting structures or related frameworks that the proposed framework could leverage to address security issues on M-Commerce systems as ICT4D initiatives. The proposed security framework based on the requirements discovered is then presented. As a proof-of-concept, a case study was undertaken at the Siyakhula Living Lab at Dwesa in the Eastern Cape province of South Africa in order to validate the components of the proposed framework. Following the application of the framework in a case study, it can be argued that the proposed security framework allows for secure transacting by marginalised users using M-Commerce initiatives. The security framework is therefore useful in addressing the identified security requirements of M-Commerce in ICT4D contexts.
- Full Text:
- Date Issued: 2014
Development of conservation methods for gunnera perpensa l.: an overexploited medicinal plant in the Eastern Cape, South Africa
- Authors: Chigor, Chinyere Blessing
- Date: 2014
- Subjects: Gunnera -- South Africa -- Eastern Cape , Medicinal plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape , Medical anthropology -- South Africa -- Eastern Cape , Medical policy -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Botany)
- Identifier: vital:11311 , http://hdl.handle.net/10353/d1019832 , Gunnera -- South Africa -- Eastern Cape , Medicinal plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape , Medical anthropology -- South Africa -- Eastern Cape , Medical policy -- South Africa -- Eastern Cape
- Description: South Africa, many plants which are used in traditional medicines are collected from wild populations. The high demand for trade and use of these medicinal plants place an enormous pressure on their natural populations, especially because they are indiscriminately harvested. The most affected of these plant species are those harvested from their underground parts, among which is Gunnera perpensa L. Gunnera perpensa is of considerable ethnobotanical interest in traditional medicine because of its wide usage. The rhizomes are widely used and indiscriminately collected in large quantities from the wild to meet the ever increasing demand in traditional medicine markets. As a result, this valuable medicinal plant species is being endangered. According to the Red List of South African Plants, the conservation status of G. perpensa has been listed as ‘declining’. The ethnobotanical survey conducted as part of this research confirms the plant species as threatened. It is, therefore, important to develop propagation and conservation strategies for this medicinal plant. Clonal propagation of G. perpensa was conducted using varying lengths of the rhizome (1, 2, 3, 4 and 5 cm) segments as propagules. While regeneration was possible with all the rhizome lengths, most of the growth parameters were significantly higher in the 5 cm rhizomes than the other rhizome segments. The appropriate planting depth for the rhizomes was also determined and 4 or 5 cm planting depths were found appropriate. No significant difference was observed in the growth parameters amongst the planting depths; nevertheless, 4 cm depth gave higher growth and yield. The results of this study show that regenerating G. perpensa.
- Full Text:
- Date Issued: 2014
- Authors: Chigor, Chinyere Blessing
- Date: 2014
- Subjects: Gunnera -- South Africa -- Eastern Cape , Medicinal plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape , Medical anthropology -- South Africa -- Eastern Cape , Medical policy -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Botany)
- Identifier: vital:11311 , http://hdl.handle.net/10353/d1019832 , Gunnera -- South Africa -- Eastern Cape , Medicinal plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape , Medical anthropology -- South Africa -- Eastern Cape , Medical policy -- South Africa -- Eastern Cape
- Description: South Africa, many plants which are used in traditional medicines are collected from wild populations. The high demand for trade and use of these medicinal plants place an enormous pressure on their natural populations, especially because they are indiscriminately harvested. The most affected of these plant species are those harvested from their underground parts, among which is Gunnera perpensa L. Gunnera perpensa is of considerable ethnobotanical interest in traditional medicine because of its wide usage. The rhizomes are widely used and indiscriminately collected in large quantities from the wild to meet the ever increasing demand in traditional medicine markets. As a result, this valuable medicinal plant species is being endangered. According to the Red List of South African Plants, the conservation status of G. perpensa has been listed as ‘declining’. The ethnobotanical survey conducted as part of this research confirms the plant species as threatened. It is, therefore, important to develop propagation and conservation strategies for this medicinal plant. Clonal propagation of G. perpensa was conducted using varying lengths of the rhizome (1, 2, 3, 4 and 5 cm) segments as propagules. While regeneration was possible with all the rhizome lengths, most of the growth parameters were significantly higher in the 5 cm rhizomes than the other rhizome segments. The appropriate planting depth for the rhizomes was also determined and 4 or 5 cm planting depths were found appropriate. No significant difference was observed in the growth parameters amongst the planting depths; nevertheless, 4 cm depth gave higher growth and yield. The results of this study show that regenerating G. perpensa.
- Full Text:
- Date Issued: 2014
Development of Graphene/CdSe Quantum Dots‐Co Phthalocyanine Nanocomposite for Oxygen Reduction Reaction
- Nyoni, Stephen, Nyokong, Tebello
- Authors: Nyoni, Stephen , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189944 , vital:44950 , xlink:href="https://doi.org/10.1002/elan.201400372"
- Description: Nanocomposites containing CdSe quantum dots, tetra(4-(4,6-diaminopyrimidin-2-ylthio) phthalocyaninatocobalt(II)) (CoPyPc) and reduced graphene nanosheets (rGNS) were devoloped and used for the modification of a glassy carbon electrode. Characterization of the nanocomposites was done by transmission electron microscopy (TEM) and X-ray diffraction (XRD) analyses. Cyclic voltammetry (CV) was used for electrochemical characterization of the prepared nanocomposite for oxygen reduction reaction. The oxygen reduction activity for rGNS/CdSe-CoPyPc nanocomposite was found to be superior over the individual nanomaterials in this study. The activity of the nanocomposite towards oxygen reduction was also tested for tolerance to methanol crossover effect using chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) studies.
- Full Text:
- Date Issued: 2014
- Authors: Nyoni, Stephen , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189944 , vital:44950 , xlink:href="https://doi.org/10.1002/elan.201400372"
- Description: Nanocomposites containing CdSe quantum dots, tetra(4-(4,6-diaminopyrimidin-2-ylthio) phthalocyaninatocobalt(II)) (CoPyPc) and reduced graphene nanosheets (rGNS) were devoloped and used for the modification of a glassy carbon electrode. Characterization of the nanocomposites was done by transmission electron microscopy (TEM) and X-ray diffraction (XRD) analyses. Cyclic voltammetry (CV) was used for electrochemical characterization of the prepared nanocomposite for oxygen reduction reaction. The oxygen reduction activity for rGNS/CdSe-CoPyPc nanocomposite was found to be superior over the individual nanomaterials in this study. The activity of the nanocomposite towards oxygen reduction was also tested for tolerance to methanol crossover effect using chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) studies.
- Full Text:
- Date Issued: 2014
Development of polymer templates for ZnO nanorods
- Authors: Dobson, Stephen Robert
- Date: 2014
- Subjects: Polymers , Semiconductor industry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10556 , http://hdl.handle.net/10948/d1020805
- Description: One of the biggest challenges for the semiconductor industry is the development of nanofabrication techniques that allow for the fabrication of structures on a scale tens of nanometers in size. This provides greater potential functionality at reduced costs. Established conventional techniques, such as photolithography, are unable to achieve features below 30 nm due to the inherent limitations of the wavelength of light sources currently available. For this reason block copolymers received considerable attention in order to overcome these challenges in lithographic technology. Block copolymers have an inherent processing advantage of self assembling into various nanoscopic structures such as spheres, cylinders and lamellae amongst others on a scale below 50 nm. The dimensions and structures are readily tuneable based on molecular weights (Mw) and compositions of the copolymers. However, to be usable within industry a great deal more research still needs to be conducted on the use and nature of block copolymers. In this study the block copolymer of poly(styrene-block-methylmethacrylate) (PS-b-PMMA) was investigated as a potential nano-mask for semiconductor growth. Research was conducted on thin films of PS-b-PMMA by altering the parameters influencing the kinetics and thermodynamic effects on the thin films, in order to produce a structure of cylinders of PMMA perpendicular to the substrate within a PS matrix on a silicon (Si) substrate. It is shown that thermally annealing the PS-b-PMMA thin films under conditions where there is no preferential interaction of the substrate or open surface with either components of the block copolymer (i.e. PS or PMMA with Si or ambient) and at an appropriate thin film thickness, perpendicular cylinders of PMMA within a PS matrix form in the thin films. The determined ideal thin film thickness is 32 nm, with non-preferential interaction attained between block and substrate by coating a poly(styrene-random-methylmethacrylate) (PS-r-PMMA) on the Si substrate and annealing within a vacuum. Additionally, acetic acid, as a known selective solvent of PMMA, is used to further process the thin film of PS-b-PMMA. Thus a final PS nano-mask containing pores with a diameter tens of nanometers in size is produced. The pores are shown to have an average diameter of 13.5 nm. Measurements were taken throughout the investigation using a scanning probe microscope (SPM) to determine surface topography and phase morphology of the PS-b-PMMA thin films. X-ray reflectometry (XRR) is used to measure film thickness. The research in this study shows that thin films of PS containing hexagonally arranged pores can be produced and could find potential use as a nano-mask for semiconductor growth.
- Full Text:
- Date Issued: 2014
- Authors: Dobson, Stephen Robert
- Date: 2014
- Subjects: Polymers , Semiconductor industry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10556 , http://hdl.handle.net/10948/d1020805
- Description: One of the biggest challenges for the semiconductor industry is the development of nanofabrication techniques that allow for the fabrication of structures on a scale tens of nanometers in size. This provides greater potential functionality at reduced costs. Established conventional techniques, such as photolithography, are unable to achieve features below 30 nm due to the inherent limitations of the wavelength of light sources currently available. For this reason block copolymers received considerable attention in order to overcome these challenges in lithographic technology. Block copolymers have an inherent processing advantage of self assembling into various nanoscopic structures such as spheres, cylinders and lamellae amongst others on a scale below 50 nm. The dimensions and structures are readily tuneable based on molecular weights (Mw) and compositions of the copolymers. However, to be usable within industry a great deal more research still needs to be conducted on the use and nature of block copolymers. In this study the block copolymer of poly(styrene-block-methylmethacrylate) (PS-b-PMMA) was investigated as a potential nano-mask for semiconductor growth. Research was conducted on thin films of PS-b-PMMA by altering the parameters influencing the kinetics and thermodynamic effects on the thin films, in order to produce a structure of cylinders of PMMA perpendicular to the substrate within a PS matrix on a silicon (Si) substrate. It is shown that thermally annealing the PS-b-PMMA thin films under conditions where there is no preferential interaction of the substrate or open surface with either components of the block copolymer (i.e. PS or PMMA with Si or ambient) and at an appropriate thin film thickness, perpendicular cylinders of PMMA within a PS matrix form in the thin films. The determined ideal thin film thickness is 32 nm, with non-preferential interaction attained between block and substrate by coating a poly(styrene-random-methylmethacrylate) (PS-r-PMMA) on the Si substrate and annealing within a vacuum. Additionally, acetic acid, as a known selective solvent of PMMA, is used to further process the thin film of PS-b-PMMA. Thus a final PS nano-mask containing pores with a diameter tens of nanometers in size is produced. The pores are shown to have an average diameter of 13.5 nm. Measurements were taken throughout the investigation using a scanning probe microscope (SPM) to determine surface topography and phase morphology of the PS-b-PMMA thin films. X-ray reflectometry (XRR) is used to measure film thickness. The research in this study shows that thin films of PS containing hexagonally arranged pores can be produced and could find potential use as a nano-mask for semiconductor growth.
- Full Text:
- Date Issued: 2014