Foreign aid mix and manufactured exports performance in sub-Saharan Africa
- Authors: Ndalama, Jewel Stebbins
- Date: 2024-10-11
- Subjects: Manufactures , Economic assistance Africa, Sub-Saharan , Terms of trade , Comparative advantage (International trade) , Heckscher-Ohlin principle , Free trade , Import substitution , Foreign trade promotion
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466361 , vital:76721 , DOI 10.21504/10962/466361
- Description: This study aims at finding out effects of foreign aid mix on manufactured exports performance in Sub-Saharan Africa. This is important as the region has lagged behind on promotion of manufactured exports thereby relying on primary exports. For a country’s exports to be competitive internationally, and hence improve economically, it has to manufacture products part of which can be exported. Sub-Saharan African countries have relied on primary exports which fetch low prices at international market thereby bringing in low foreign exchange. This is why African countries have relied on foreign aid since they cannot generate enough foreign exchange which is needed to import goods and services they cannot produce domestically. African countries have to boost manufactured exports which fetch high prices at international market hence they bring in the much-needed foreign exchange. Reliance on foreign aid may not be sustainable as donors have their own priorities and may not be able to give aid indefinitely. African countries have to find sustainable ways of generating foreign exchange one of which is to boost manufactured exports. As boosting manufactured exports in these countries requires resources, foreign aid can be used to improve manufacturing and manufactured exports. In this case, the countries can later stop relying on foreign aid. This study first examines the impact of foreign aid on terms of trade. Holding price of imports constant, improvement in terms of trade means that either prices of primary exports have increased or there has been improvement in manufactured exports which are known to fetch high prices at international market. The study then examines the impact of foreign aid on manufactured exports. Most of the studies have dwelt on the impact of foreign aid on exports. This study has gone further to assess the impact of foreign aid on one of the components of exports namely manufactured exports. Thereafter, the study examines the impact of disaggregated foreign aid on manufactured exports. While some studies have criticised foreign aid as having little or no impact on recipient country, it is necessary to disaggregate the aid by sector since aid to some sectors may have positive impact on those sectors, and other sectors of the economy. The study has also examined asymmetric effects of various types of foreign aid, that is, whether or not, positive and negative changes of each type of aid have the same impact on manufactured exports. The study uses both panel and pooled data for 30 Sub-Saharan African countries for the period from 1970 to 2019. Models used include Autoregressive Distributed Lag (ARDL), Non-linear Autoregressive Distributed Lag (NARDL), Generalised Least Squares (GLS), among other models. The study has found that foreign aid has a negative and statistically significant impact on terms of trade. This means that foreign aid does not improve export prices relative to those of imports in the Sub-Saharan African countries. According to Prebisch-Singer Dependency Theory, price of primary commodities declines relative to the price of manufactured goods, causing terms of trade of primary product-based economies to deteriorate. This study has shown that foreign aid deteriorates terms of trade thereby worsening the situation of African countries which mainly export primary commodities and import manufactured products. This calls for African economies to diversify their export base to include manufactured exports, otherwise, foreign aid, which is one of the main sources of resources for African economies will keep on worsening the countries’ terms of trade. Further, the study finds that foreign aid has negative impact on manufactured exports. Like other studies that have disputed the impact of foreign aid on economic growth, this study has also found that foreign aid does not have a positive impact on manufactured exports, one of the most important factors influencing economic growth in any country. This calls for policy reform on building manufacturing capabilities in the Sub-Saharan African countries. Effectiveness of foreign aid also depends on dynamics of a country as country specific results show varying effects of foreign aid on manufactured exports, with some countries experiencing positive impact and others negative impact. Donors should therefore be assessing whether in the prospective recipient country, foreign aid will have a positive impact on manufactured exports especially if their aim is to boost manufactured exports. Though total aid has a negative and statistically insignificant impact on manufactured exports, disaggregating it shows that other types of aid such as grants, agricultural aid and health aid have positive and statistically significant impacts. Thus, criticising foreign aid is not proper as some of its components have positive impact on manufactured exports. Therefore, allocating foreign aid to sectors that can impact positively on manufactured exports will go a long way in boosting manufactured exports in these countries. In addition to assessing recipient countries, donors should assess sectors in each country to find out sectors which if funded can boost manufactured exports. Country-specific results show different impacts of different types of aid with some types having positive impact, and others negative impact on manufactured exports. This means that the effectiveness of different types of foreign aid depends on a country. The study has also shown that there are no asymmetric effects of all types of aid meaning that there are no significant differences in impacts of positive or negative changes in the types of aid. Fixed capital (proxy for infrastructure development), foreign direct investment, and openness are found to be positively related to manufactured exports and statistically significant regardless of model used, and whether data used is pooled or panel. This calls for other ways of improving manufactured exports in the region. Improving infrastructure (fixed capital), attracting foreign direct investment, and opening up Sub-Saharan African countries can go a long way in promoting manufactured exports in the region. The study also ran regressions after including private sector credit, and excluding Zimbabwe, a country that faced economic challenges during the study period especially towards the end of the study period to the extent that macroeconomic fundamentals were far from being normal. However, results are not much different from results without private sector credit, and inclusion of Zimbabwe. , Thesis (PhD) -- Faculty of Commerce, Economics and Economic History, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Ndalama, Jewel Stebbins
- Date: 2024-10-11
- Subjects: Manufactures , Economic assistance Africa, Sub-Saharan , Terms of trade , Comparative advantage (International trade) , Heckscher-Ohlin principle , Free trade , Import substitution , Foreign trade promotion
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466361 , vital:76721 , DOI 10.21504/10962/466361
- Description: This study aims at finding out effects of foreign aid mix on manufactured exports performance in Sub-Saharan Africa. This is important as the region has lagged behind on promotion of manufactured exports thereby relying on primary exports. For a country’s exports to be competitive internationally, and hence improve economically, it has to manufacture products part of which can be exported. Sub-Saharan African countries have relied on primary exports which fetch low prices at international market thereby bringing in low foreign exchange. This is why African countries have relied on foreign aid since they cannot generate enough foreign exchange which is needed to import goods and services they cannot produce domestically. African countries have to boost manufactured exports which fetch high prices at international market hence they bring in the much-needed foreign exchange. Reliance on foreign aid may not be sustainable as donors have their own priorities and may not be able to give aid indefinitely. African countries have to find sustainable ways of generating foreign exchange one of which is to boost manufactured exports. As boosting manufactured exports in these countries requires resources, foreign aid can be used to improve manufacturing and manufactured exports. In this case, the countries can later stop relying on foreign aid. This study first examines the impact of foreign aid on terms of trade. Holding price of imports constant, improvement in terms of trade means that either prices of primary exports have increased or there has been improvement in manufactured exports which are known to fetch high prices at international market. The study then examines the impact of foreign aid on manufactured exports. Most of the studies have dwelt on the impact of foreign aid on exports. This study has gone further to assess the impact of foreign aid on one of the components of exports namely manufactured exports. Thereafter, the study examines the impact of disaggregated foreign aid on manufactured exports. While some studies have criticised foreign aid as having little or no impact on recipient country, it is necessary to disaggregate the aid by sector since aid to some sectors may have positive impact on those sectors, and other sectors of the economy. The study has also examined asymmetric effects of various types of foreign aid, that is, whether or not, positive and negative changes of each type of aid have the same impact on manufactured exports. The study uses both panel and pooled data for 30 Sub-Saharan African countries for the period from 1970 to 2019. Models used include Autoregressive Distributed Lag (ARDL), Non-linear Autoregressive Distributed Lag (NARDL), Generalised Least Squares (GLS), among other models. The study has found that foreign aid has a negative and statistically significant impact on terms of trade. This means that foreign aid does not improve export prices relative to those of imports in the Sub-Saharan African countries. According to Prebisch-Singer Dependency Theory, price of primary commodities declines relative to the price of manufactured goods, causing terms of trade of primary product-based economies to deteriorate. This study has shown that foreign aid deteriorates terms of trade thereby worsening the situation of African countries which mainly export primary commodities and import manufactured products. This calls for African economies to diversify their export base to include manufactured exports, otherwise, foreign aid, which is one of the main sources of resources for African economies will keep on worsening the countries’ terms of trade. Further, the study finds that foreign aid has negative impact on manufactured exports. Like other studies that have disputed the impact of foreign aid on economic growth, this study has also found that foreign aid does not have a positive impact on manufactured exports, one of the most important factors influencing economic growth in any country. This calls for policy reform on building manufacturing capabilities in the Sub-Saharan African countries. Effectiveness of foreign aid also depends on dynamics of a country as country specific results show varying effects of foreign aid on manufactured exports, with some countries experiencing positive impact and others negative impact. Donors should therefore be assessing whether in the prospective recipient country, foreign aid will have a positive impact on manufactured exports especially if their aim is to boost manufactured exports. Though total aid has a negative and statistically insignificant impact on manufactured exports, disaggregating it shows that other types of aid such as grants, agricultural aid and health aid have positive and statistically significant impacts. Thus, criticising foreign aid is not proper as some of its components have positive impact on manufactured exports. Therefore, allocating foreign aid to sectors that can impact positively on manufactured exports will go a long way in boosting manufactured exports in these countries. In addition to assessing recipient countries, donors should assess sectors in each country to find out sectors which if funded can boost manufactured exports. Country-specific results show different impacts of different types of aid with some types having positive impact, and others negative impact on manufactured exports. This means that the effectiveness of different types of foreign aid depends on a country. The study has also shown that there are no asymmetric effects of all types of aid meaning that there are no significant differences in impacts of positive or negative changes in the types of aid. Fixed capital (proxy for infrastructure development), foreign direct investment, and openness are found to be positively related to manufactured exports and statistically significant regardless of model used, and whether data used is pooled or panel. This calls for other ways of improving manufactured exports in the region. Improving infrastructure (fixed capital), attracting foreign direct investment, and opening up Sub-Saharan African countries can go a long way in promoting manufactured exports in the region. The study also ran regressions after including private sector credit, and excluding Zimbabwe, a country that faced economic challenges during the study period especially towards the end of the study period to the extent that macroeconomic fundamentals were far from being normal. However, results are not much different from results without private sector credit, and inclusion of Zimbabwe. , Thesis (PhD) -- Faculty of Commerce, Economics and Economic History, 2024
- Full Text:
- Date Issued: 2024-10-11
Exploring senior phase teachers’ use of Kahoot! Gamification as a formative assessment tool to scaffold mathematical understanding
- Authors: Balele, Silence
- Date: 2024-04
- Subjects: Kahoot! Algebra by DragonBox , Mathematics Computer-assisted instruction , Pedagogical content knowledge , Mathematics Study and teaching (Secondary) South Africa , Gamification , Educational technology , Mathematics teachers Training of South Africa
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/423891 , vital:72102
- Description: In South Africa, digital technology, particularly gamification, continues to become an important teaching and learning tool. Its importance lies in scaffolding mathematical understanding, improving the quality of assessment, and developing twenty-first-century technological skills for effective mathematics assessment. To explore this importance, senior phase mathematics teachers are encouraged to adopt gamification technology such as Kahoot! in assessment. The study adopted a case study research design with a interpretivist research paradigm, as this method allows detailed exploration and understanding of a specific context through a close connection with the participants. Data was collected using semi-structured questionnaires, focus group interviews, non-participant observations, and reflective journals. The research involved ten purposively selected senior-phase mathematics teachers from two schools in the Sarah Baartman District, Eastern Cape Province, South Africa. The study drew upon Vygoysky's Sociocultural Theory for its theoretical framework, while the Technological, Pedagogical, and Content Knowledge was used for analysis. The data analysis pursued an inductive approach. Adopting a thematic analysis included coding participant responses, organizing codes into concepts and categories, and developing a theoretical framework from the resultant categories. A four-phase process was involved: coding, conceptualizing, categorizing, and theorizing, was employed. This process and using NVivo software for data organization and management helped identify patterns, themes, and significant concerns surrounding the study's core subject. The findings from the study were as follows: Firstly, it was revealed that most teachers have a positive perception and attitude towards using Kahoot! for formative assessment, believing that it enhances teaching and learning quality. However, they showed scepticism due to insufficient Information and Communication Technologies knowledge and training. Second, teachers' pedagogical and technological experiences were predominantly enjoyable. Kahoot! was accepted as beneficial for promoting collaboration, interaction, and immediate feedback. Third, the study identified enabling and constraining factors in using Kahoot! for formative assessment. The enabling factors include Kahoot!, which was convenient and accessible, promoted immediate feedback and fostered collaboration and interaction. The constraining factors include Information and Communication Technologies and network interference, which posed limitations. The research concluded that Kahoot! as a platform for formative assessment indeed scaffold mathematical understanding. The study recommends increasing teachers' access to educational technology, incorporating continuous professional development programs, providing subject-specific training, and encouraging teachers to adapt to emerging technologies. The study also provided recommendations for future research to explore learner perceptions, employ a mixed methods approach to help quantify learner performance and investigate the pedagogical and technological experiences of senior phase mathematics teachers regarding formative assessment. , Thesis (MEd) -- Faculty of Education, Secondary and Post-School Education, 2024
- Full Text:
- Date Issued: 2024-04
- Authors: Balele, Silence
- Date: 2024-04
- Subjects: Kahoot! Algebra by DragonBox , Mathematics Computer-assisted instruction , Pedagogical content knowledge , Mathematics Study and teaching (Secondary) South Africa , Gamification , Educational technology , Mathematics teachers Training of South Africa
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/423891 , vital:72102
- Description: In South Africa, digital technology, particularly gamification, continues to become an important teaching and learning tool. Its importance lies in scaffolding mathematical understanding, improving the quality of assessment, and developing twenty-first-century technological skills for effective mathematics assessment. To explore this importance, senior phase mathematics teachers are encouraged to adopt gamification technology such as Kahoot! in assessment. The study adopted a case study research design with a interpretivist research paradigm, as this method allows detailed exploration and understanding of a specific context through a close connection with the participants. Data was collected using semi-structured questionnaires, focus group interviews, non-participant observations, and reflective journals. The research involved ten purposively selected senior-phase mathematics teachers from two schools in the Sarah Baartman District, Eastern Cape Province, South Africa. The study drew upon Vygoysky's Sociocultural Theory for its theoretical framework, while the Technological, Pedagogical, and Content Knowledge was used for analysis. The data analysis pursued an inductive approach. Adopting a thematic analysis included coding participant responses, organizing codes into concepts and categories, and developing a theoretical framework from the resultant categories. A four-phase process was involved: coding, conceptualizing, categorizing, and theorizing, was employed. This process and using NVivo software for data organization and management helped identify patterns, themes, and significant concerns surrounding the study's core subject. The findings from the study were as follows: Firstly, it was revealed that most teachers have a positive perception and attitude towards using Kahoot! for formative assessment, believing that it enhances teaching and learning quality. However, they showed scepticism due to insufficient Information and Communication Technologies knowledge and training. Second, teachers' pedagogical and technological experiences were predominantly enjoyable. Kahoot! was accepted as beneficial for promoting collaboration, interaction, and immediate feedback. Third, the study identified enabling and constraining factors in using Kahoot! for formative assessment. The enabling factors include Kahoot!, which was convenient and accessible, promoted immediate feedback and fostered collaboration and interaction. The constraining factors include Information and Communication Technologies and network interference, which posed limitations. The research concluded that Kahoot! as a platform for formative assessment indeed scaffold mathematical understanding. The study recommends increasing teachers' access to educational technology, incorporating continuous professional development programs, providing subject-specific training, and encouraging teachers to adapt to emerging technologies. The study also provided recommendations for future research to explore learner perceptions, employ a mixed methods approach to help quantify learner performance and investigate the pedagogical and technological experiences of senior phase mathematics teachers regarding formative assessment. , Thesis (MEd) -- Faculty of Education, Secondary and Post-School Education, 2024
- Full Text:
- Date Issued: 2024-04
Exploring youth unemployment through entrepreneurship education: a case study of Biziniz in the box in Newcastle
- Ndlovu, Bonginkosi Siphelele
- Authors: Ndlovu, Bonginkosi Siphelele
- Date: 2024-04
- Subjects: Youth -- Employment -- South Africa -- KwaZulu Natal , Entrepreneurship -- South Africa -- KwaZulu Natal , Economic development -- South Africa -- KwaZulu Natal
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63386 , vital:73267
- Description: Youth unemployment is a long-standing social and economic issue in South Africa. One possible drive behind the ever-increasing rate of youth unemployment is the school curriculum that is still tainted by the so-called “bantu education” which is training learners to be job seekers rather than job creators. Government-led initiatives have served to empower the youth through capacity-building projects and financial assistance. One such example is the Bizniz in the Box initiative. Using a qualitative research methodology, and by examining Bizniz in the Box as a case study, this study sought to explore the types of methods, strategies, and outcomes that the Bizniz in the Box initiative used and produced, along with its role in imparting entrepreneurship knowledge and skill to its participants. Through such strategies, the study aimed also to find the possible role the government could have in the imparting of entrepreneurship education. By employing Vygotsky’s Activity Theory (1978) and drawing extensively on Paulo Freire’s Pedagogy of the Oppressed (1970), the study seeks to make recommendations on how government initiatives could critically engage with school curricula and the ways in which government intervention and initiatives can aid school teachers that are ill-trained to impart entrepreneurship skill and knowledge, which is vital to abate the problem of youth unemployment. , Thesis (MA) -- Faculty of Humanities, School of Governmental and Social Sciences, 2024
- Full Text:
- Date Issued: 2024-04
- Authors: Ndlovu, Bonginkosi Siphelele
- Date: 2024-04
- Subjects: Youth -- Employment -- South Africa -- KwaZulu Natal , Entrepreneurship -- South Africa -- KwaZulu Natal , Economic development -- South Africa -- KwaZulu Natal
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63386 , vital:73267
- Description: Youth unemployment is a long-standing social and economic issue in South Africa. One possible drive behind the ever-increasing rate of youth unemployment is the school curriculum that is still tainted by the so-called “bantu education” which is training learners to be job seekers rather than job creators. Government-led initiatives have served to empower the youth through capacity-building projects and financial assistance. One such example is the Bizniz in the Box initiative. Using a qualitative research methodology, and by examining Bizniz in the Box as a case study, this study sought to explore the types of methods, strategies, and outcomes that the Bizniz in the Box initiative used and produced, along with its role in imparting entrepreneurship knowledge and skill to its participants. Through such strategies, the study aimed also to find the possible role the government could have in the imparting of entrepreneurship education. By employing Vygotsky’s Activity Theory (1978) and drawing extensively on Paulo Freire’s Pedagogy of the Oppressed (1970), the study seeks to make recommendations on how government initiatives could critically engage with school curricula and the ways in which government intervention and initiatives can aid school teachers that are ill-trained to impart entrepreneurship skill and knowledge, which is vital to abate the problem of youth unemployment. , Thesis (MA) -- Faculty of Humanities, School of Governmental and Social Sciences, 2024
- Full Text:
- Date Issued: 2024-04
Third generation calibrations for Meerkat Observation of Saraswati Supercluster
- Authors: Kincaid, Robert Daniel
- Date: 2022-10-14
- Subjects: Square Kilometre Array (Project) , Superclusters , Saraswati Supercluster , Radio astronomy , MeerKAT , Calibration
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/362916 , vital:65374
- Description: The international collaboration of the Square Kilometre Array (SKA), which is one of the largest and most challenging science projects of the 21st century, will bring a revolution in radio astronomy in terms of sensitivity and resolution. The recent launch of several new radio instruments, combined with the subsequent developments in calibration and imaging techniques, has dramatically advanced this field over the past few years, thus enhancing our knowledge of the radio universe. Various SKA pathfinders around the world have been developed (and more are planned for construction) that have laid down a firm foundation for the SKA in terms of science while additionally giving insight into the technological requirements required for the projected data outputs to become manageable. South Africa has recently built the new MeerKAT telescope, which is a SKA precursor forming an integral part of SKA-mid component. The MeerKAT instrument has unprecedented sensitivity that can cater for the required science goals of the current and future SKA era. It is noticeable from MeerKAT and other precursors that the data produced by these instruments are significantly challenging to calibrate and image. Calibration-related artefacts intrinsic to bright sources are of major concern since, they limit the Dynamic Range (DR) and image fidelity of the resulting images and cause flux suppression of extended sources. Diffuse radio sources from galaxy clusters in the form of halos, relics and most recently bridges on the Mpc scale, because of their diffuse nature combined with wide field of view (FoV) observations, make them particularly good candidates for testing the different approaches of calibration. , Thesis (MSc) -- Faculty of Science, Physics and Electronics, 2022
- Full Text:
- Date Issued: 2022-10-14
- Authors: Kincaid, Robert Daniel
- Date: 2022-10-14
- Subjects: Square Kilometre Array (Project) , Superclusters , Saraswati Supercluster , Radio astronomy , MeerKAT , Calibration
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/362916 , vital:65374
- Description: The international collaboration of the Square Kilometre Array (SKA), which is one of the largest and most challenging science projects of the 21st century, will bring a revolution in radio astronomy in terms of sensitivity and resolution. The recent launch of several new radio instruments, combined with the subsequent developments in calibration and imaging techniques, has dramatically advanced this field over the past few years, thus enhancing our knowledge of the radio universe. Various SKA pathfinders around the world have been developed (and more are planned for construction) that have laid down a firm foundation for the SKA in terms of science while additionally giving insight into the technological requirements required for the projected data outputs to become manageable. South Africa has recently built the new MeerKAT telescope, which is a SKA precursor forming an integral part of SKA-mid component. The MeerKAT instrument has unprecedented sensitivity that can cater for the required science goals of the current and future SKA era. It is noticeable from MeerKAT and other precursors that the data produced by these instruments are significantly challenging to calibrate and image. Calibration-related artefacts intrinsic to bright sources are of major concern since, they limit the Dynamic Range (DR) and image fidelity of the resulting images and cause flux suppression of extended sources. Diffuse radio sources from galaxy clusters in the form of halos, relics and most recently bridges on the Mpc scale, because of their diffuse nature combined with wide field of view (FoV) observations, make them particularly good candidates for testing the different approaches of calibration. , Thesis (MSc) -- Faculty of Science, Physics and Electronics, 2022
- Full Text:
- Date Issued: 2022-10-14
Corrosion and hydrogen resistant modified zirlo surfaces for nuclear fuel cladding
- Authors: Ngongo, Sinoyolo
- Date: 2021-12
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/54077 , vital:46252
- Description: Zirconium (Zr) alloys are used as fuel cladding material in all modern water cooled commercial nuclear reactors. Zr alloys have many desirable properties for the nuclear reactor core environment, however, it also has a weakness in that overheated zirconium alloy fuel rods react with hot steam resulting in the release of hydrogen. High temperatures increase the oxidation rate and hence the hydrogen production rate which in turn increase the risk of a hydrogen gas explosion such as what is surmised to have happened in the 2011 Fukushima Daiichi nuclear plant incident. The some of the hydrogen produced will also diffuse into the zirconium alloy and form zirconium hydrides which will weaken the original zirconium alloy material. The development of accident tolerant fuel became a major focus area after the Fukushima event in March 2011 with the U.S. congress directing the U.S. Department of Energy to develop fuel with enhanced accident tolerance at high temperatures. The main objective in the case of zirconium alloy cladding has been the modification of cladding surface layers by coating or doping in order to reduce the oxidation rate and hydrogen generation rate by the reaction of steam with zirconium alloy cladding at high temperatures. This thesis focuses on two surface modifications to decrease the surface corrosion rate of ZIRLOTM (the Zr alloy used in this study) and reduce hydrogen uptake by ZIRLO. The first modification involves an oxidation-resistant nano-crystalline diamond (NCD) film deposited on ZIRLO. The NCD layer was deposited in a microwave plasma-enhanced linear antenna chemical vapor deposition (MW-LA-PECVD) system after immersion of the ZIRLO tubes in a water-based solution containing nanodiamonds. ZIRLO tube samples were coated with 200 nm and 500 nm thick NCD layers. The 200 nm thick NCD coated ZIRLO was kept as control sample whereas the 500 nm thick NCD coated ZIRLO was exposed to steam oxidation at 360 °C for 90 days. The results revealed that the NCD exfoliated in some areas leaving the ZIRLO exposed to the steam. In the areas where the diamond did not exfoliate, the diamond was still attached to the ZIRLO with an amorphous carbon layer present between the NCD and the zirconium oxide layer.The transmission electron microscopy (TEM) results of this study indicate the presence a sp3 – hybridised diamond phase for the NCD layer as well as an intermediate amorphous carbon layer between the NCD and ZrO2 layers. Analyses of the area where the NCD layer had exfoliated showed no evidence of an NCD layer. It is possible that the amorphous carbon layer between the diamond and the zirconium oxide is responsible for weak interfacial bonding leading to partial exfoliation during oxidation in steam 360 °C for 90 days. In the second modification, the effectiveness of a Cr doped ZrO2 layer to reduce the migration rate of hydrogen in ZrO2 was investigated. The ZIRLO tube used for this part of the study did not have a thin oxide passivation surface layer. Two different procedures were used to create chromium doped zirconium oxide surface layers on ZIRLO. The ZIRLO surface was coated with chromium using cathodic arc deposition followed compression plasma flow (CPF) treatment to facilitate intermixing of the Cr and the ZIRLO. In procedure 1, the surface modification was achieved through the incorporation of chromium into the zirconium surface layer using a compression plasma flow (CPF) technique, followed by the oxidation of the chromium doped zirconium. The oxidation process was conducted at 500 °C for 6 hours. In procedure 2, the chromium was incorporated into the zirconium oxide layer again using the CPF technique. Hydrogen desorption was measured from pure ZIRLO and CPF modified samples using a special gas reaction controller system. The key finding of the results is that the chromium doped (incorporated) zirconium oxide layer on ZIRLO sample exhibited the lowest hydrogen desorption rate of all the samples analysed. This indicates that H in the Cr doped zirconium oxide layer had the lowest mobility of all the samples investigated. This is consistent with the theoretical predictions that the doping of ZrO2 by Cr reduces the solubility of hydrogen in ZrO2. , Thesis (PhD) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2021
- Full Text: false
- Date Issued: 2021-12
- Authors: Ngongo, Sinoyolo
- Date: 2021-12
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/54077 , vital:46252
- Description: Zirconium (Zr) alloys are used as fuel cladding material in all modern water cooled commercial nuclear reactors. Zr alloys have many desirable properties for the nuclear reactor core environment, however, it also has a weakness in that overheated zirconium alloy fuel rods react with hot steam resulting in the release of hydrogen. High temperatures increase the oxidation rate and hence the hydrogen production rate which in turn increase the risk of a hydrogen gas explosion such as what is surmised to have happened in the 2011 Fukushima Daiichi nuclear plant incident. The some of the hydrogen produced will also diffuse into the zirconium alloy and form zirconium hydrides which will weaken the original zirconium alloy material. The development of accident tolerant fuel became a major focus area after the Fukushima event in March 2011 with the U.S. congress directing the U.S. Department of Energy to develop fuel with enhanced accident tolerance at high temperatures. The main objective in the case of zirconium alloy cladding has been the modification of cladding surface layers by coating or doping in order to reduce the oxidation rate and hydrogen generation rate by the reaction of steam with zirconium alloy cladding at high temperatures. This thesis focuses on two surface modifications to decrease the surface corrosion rate of ZIRLOTM (the Zr alloy used in this study) and reduce hydrogen uptake by ZIRLO. The first modification involves an oxidation-resistant nano-crystalline diamond (NCD) film deposited on ZIRLO. The NCD layer was deposited in a microwave plasma-enhanced linear antenna chemical vapor deposition (MW-LA-PECVD) system after immersion of the ZIRLO tubes in a water-based solution containing nanodiamonds. ZIRLO tube samples were coated with 200 nm and 500 nm thick NCD layers. The 200 nm thick NCD coated ZIRLO was kept as control sample whereas the 500 nm thick NCD coated ZIRLO was exposed to steam oxidation at 360 °C for 90 days. The results revealed that the NCD exfoliated in some areas leaving the ZIRLO exposed to the steam. In the areas where the diamond did not exfoliate, the diamond was still attached to the ZIRLO with an amorphous carbon layer present between the NCD and the zirconium oxide layer.The transmission electron microscopy (TEM) results of this study indicate the presence a sp3 – hybridised diamond phase for the NCD layer as well as an intermediate amorphous carbon layer between the NCD and ZrO2 layers. Analyses of the area where the NCD layer had exfoliated showed no evidence of an NCD layer. It is possible that the amorphous carbon layer between the diamond and the zirconium oxide is responsible for weak interfacial bonding leading to partial exfoliation during oxidation in steam 360 °C for 90 days. In the second modification, the effectiveness of a Cr doped ZrO2 layer to reduce the migration rate of hydrogen in ZrO2 was investigated. The ZIRLO tube used for this part of the study did not have a thin oxide passivation surface layer. Two different procedures were used to create chromium doped zirconium oxide surface layers on ZIRLO. The ZIRLO surface was coated with chromium using cathodic arc deposition followed compression plasma flow (CPF) treatment to facilitate intermixing of the Cr and the ZIRLO. In procedure 1, the surface modification was achieved through the incorporation of chromium into the zirconium surface layer using a compression plasma flow (CPF) technique, followed by the oxidation of the chromium doped zirconium. The oxidation process was conducted at 500 °C for 6 hours. In procedure 2, the chromium was incorporated into the zirconium oxide layer again using the CPF technique. Hydrogen desorption was measured from pure ZIRLO and CPF modified samples using a special gas reaction controller system. The key finding of the results is that the chromium doped (incorporated) zirconium oxide layer on ZIRLO sample exhibited the lowest hydrogen desorption rate of all the samples analysed. This indicates that H in the Cr doped zirconium oxide layer had the lowest mobility of all the samples investigated. This is consistent with the theoretical predictions that the doping of ZrO2 by Cr reduces the solubility of hydrogen in ZrO2. , Thesis (PhD) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2021
- Full Text: false
- Date Issued: 2021-12
Foraging ecology of Kelp Gulls in natural and anthropogenically modified environments
- Authors: Reusch, Katharina
- Date: 2021-12
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/54106 , vital:46303
- Description: Humans are having a profound impact on the natural environment through a myriad of activities, such as land use change or direct exploitation of resources. Some species are able to adapt to these changes and thrive in deeply modified environments. They are often considered winners of global change. Among these are Kelp GullsLarus dominicanus in South Africa, which have a generalist foraging nature. Despite their abundance and potential role in the ecosystem, knowledge on their foraging ecology is limited, with no understanding of the role of natural and anthropogenic food resources during breeding. The aim of this thesis was to assess the foraging movements, diet and health of Kelp Gulls breeding in seven different colonies varying in proximity to landfills. GPS loggers were deployed on incubating adults to assess foraging trip patterns, effort, and habitats. Diet and trophic ecology of adults and chicks was determined during the breeding season by combining conventional diet analysis (i.e. stomach content samples and regurgitated pellets) with stable isotope analysis of blood plasma. Finally, population health was estimated using indices of body condition for adults and chicks, and blood and faecal parasites were examined. The first successful tracking data from Kelp Gulls in South Africa revealed that birds from all colonies spent more time foraging in natural environments (marine, coastal and terrestrial) than in anthropogenically modified ones, irrelevant of the distance to the nearest landfill, potentially reflecting prey profitability or availability around thebreeding colonies. Gulls also had higher foraging effort when foraging at sea (longer travelling distance), which might be balanced by foraging on high energy prey in themarine environment (e.g. fish). Diet and trophic ecology data confirmed the wide range of resources Kelp Gulls were capable of exploiting. Anthropogenic items were important food sources at some colonies, while annual differences in trophic level targeted were apparent at some other colonies, possibly reflecting varying predation levels on other seabirds. Diet and trophic ecology generally differed between adults and chicks, with chicks being fed a more marine, i.e. fish, and higher trophic level diet, potentially due to the higher energy content of fish being important for chick growth. Despite differences between colonies in foraging effort and diet, body condition of both adults and chicks was similar across colonies. Birds from one of the urban colonies, foraging at the local landfill, tended to have slightly higher body condition values, possibly due to the high fat content of anthropogenic items, although this was not significant. Blood parasites were very scarce, with only one genus identified, Haemoproteus spp. Parasite abundance was significantly lower in chicks than in adults, implicating that adults might get infected in areas outside the colony. Faecal smears revealed the presence of yeast cells (Candida spp.) in birds, coinciding with higher body condition values, possibly linked to foraging habitat choice, as birds might ingest yeast cells when feeding in urban areas contaminated with human excrement.Kelp Gulls breeding in South Africa forage on a wide variety of resources and habitats, with limited apparent impact on their parasite load and body condition. All colonies foraged to some extend on natural sources, although some colonies located in very urban areas seemed to depend more closely on anthropogenic items as food resource. Therefore, changes in e.g. landfill management might cause changes in population dynamics, with possible repercussions on neighbouring bird populations. Theirgeneralist foraging nature, among others, makes Kelp Gulls winners of global change and is partly responsible for their increased population numbers. As they are often perceived as pests, information on the foraging ecology is important to manage gull populations effectively. , Thesis (PhD) -- Faculty of Sciences, School of Environmental Sciences, 2021
- Full Text:
- Date Issued: 2021-12
- Authors: Reusch, Katharina
- Date: 2021-12
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/54106 , vital:46303
- Description: Humans are having a profound impact on the natural environment through a myriad of activities, such as land use change or direct exploitation of resources. Some species are able to adapt to these changes and thrive in deeply modified environments. They are often considered winners of global change. Among these are Kelp GullsLarus dominicanus in South Africa, which have a generalist foraging nature. Despite their abundance and potential role in the ecosystem, knowledge on their foraging ecology is limited, with no understanding of the role of natural and anthropogenic food resources during breeding. The aim of this thesis was to assess the foraging movements, diet and health of Kelp Gulls breeding in seven different colonies varying in proximity to landfills. GPS loggers were deployed on incubating adults to assess foraging trip patterns, effort, and habitats. Diet and trophic ecology of adults and chicks was determined during the breeding season by combining conventional diet analysis (i.e. stomach content samples and regurgitated pellets) with stable isotope analysis of blood plasma. Finally, population health was estimated using indices of body condition for adults and chicks, and blood and faecal parasites were examined. The first successful tracking data from Kelp Gulls in South Africa revealed that birds from all colonies spent more time foraging in natural environments (marine, coastal and terrestrial) than in anthropogenically modified ones, irrelevant of the distance to the nearest landfill, potentially reflecting prey profitability or availability around thebreeding colonies. Gulls also had higher foraging effort when foraging at sea (longer travelling distance), which might be balanced by foraging on high energy prey in themarine environment (e.g. fish). Diet and trophic ecology data confirmed the wide range of resources Kelp Gulls were capable of exploiting. Anthropogenic items were important food sources at some colonies, while annual differences in trophic level targeted were apparent at some other colonies, possibly reflecting varying predation levels on other seabirds. Diet and trophic ecology generally differed between adults and chicks, with chicks being fed a more marine, i.e. fish, and higher trophic level diet, potentially due to the higher energy content of fish being important for chick growth. Despite differences between colonies in foraging effort and diet, body condition of both adults and chicks was similar across colonies. Birds from one of the urban colonies, foraging at the local landfill, tended to have slightly higher body condition values, possibly due to the high fat content of anthropogenic items, although this was not significant. Blood parasites were very scarce, with only one genus identified, Haemoproteus spp. Parasite abundance was significantly lower in chicks than in adults, implicating that adults might get infected in areas outside the colony. Faecal smears revealed the presence of yeast cells (Candida spp.) in birds, coinciding with higher body condition values, possibly linked to foraging habitat choice, as birds might ingest yeast cells when feeding in urban areas contaminated with human excrement.Kelp Gulls breeding in South Africa forage on a wide variety of resources and habitats, with limited apparent impact on their parasite load and body condition. All colonies foraged to some extend on natural sources, although some colonies located in very urban areas seemed to depend more closely on anthropogenic items as food resource. Therefore, changes in e.g. landfill management might cause changes in population dynamics, with possible repercussions on neighbouring bird populations. Theirgeneralist foraging nature, among others, makes Kelp Gulls winners of global change and is partly responsible for their increased population numbers. As they are often perceived as pests, information on the foraging ecology is important to manage gull populations effectively. , Thesis (PhD) -- Faculty of Sciences, School of Environmental Sciences, 2021
- Full Text:
- Date Issued: 2021-12
Elucidation of a novel role for HSP70/HSP90 organising protein (Hop) in mRNA processing
- Dingle, Laura Margaret Kirkpatrick
- Authors: Dingle, Laura Margaret Kirkpatrick
- Date: 2020
- Language: English
- Type: thesis , text , Doctoral , Ph.D
- Identifier: http://hdl.handle.net/10962/59173 , vital:27449 , doi:10.21504/10962/59173
- Description: Thesis (PhD.)--Rhodes University, Faculty of Science, Biochemistry and Microbiology, 2020.
- Full Text:
- Date Issued: 2020
- Authors: Dingle, Laura Margaret Kirkpatrick
- Date: 2020
- Language: English
- Type: thesis , text , Doctoral , Ph.D
- Identifier: http://hdl.handle.net/10962/59173 , vital:27449 , doi:10.21504/10962/59173
- Description: Thesis (PhD.)--Rhodes University, Faculty of Science, Biochemistry and Microbiology, 2020.
- Full Text:
- Date Issued: 2020
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