Adaptive Neuro-Fuzzy Inference System modelling of surface topology in ultra-high precision diamond turning of rapidly solidified aluminium grade (RSA 443)
- Authors: Zvikomborero, Hweju
- Date: 2020
- Subjects: Mechatronics Surface roughness -- Measurement
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/49441 , vital:41721
- Description: Surface roughness prediction is a crucial stage during product manufacturing since it acts as a quality indicator. This investigative research thesis presents an online surface roughness prediction, based on the Adaptive Neuro-Fuzzy Inference System (ANFIS) model during Ultra-High Precision Diamond Turning (UHPDT) of Rapidly Solidified Aluminium (RSA-443) using water and kerosene as coolants. Based on the Taguchi L9 orthogonal array, the cutting parameters (spindle speed, depth of cut and feed rate) are varied at three levels. Acoustic Emission (AE) signals are detected during the UHPDT process using a piezoelectric sensor. Spindle speed, depth of cut, feed rate, AE root mean square, prominent frequency and peak rate are considered as model inputs in this thesis. The experimental results reveal that a better surface finish is obtained using water coolant in comparison to kerosene coolant. Mean Absolute Percentage Error (MAPE) based comparison between ANFIS and Response Surface Method (RSM) is carried out. In this study, the ANFIS model has a prediction accuracy of 79.42% and 69.40% on water-based and kerosene-based results respectively. The RSM model yields higher prediction accuracies of 98.59% and 95.55% on water-based and kerosene-based results respectively.
- Full Text:
- Date Issued: 2020
- Authors: Zvikomborero, Hweju
- Date: 2020
- Subjects: Mechatronics Surface roughness -- Measurement
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/49441 , vital:41721
- Description: Surface roughness prediction is a crucial stage during product manufacturing since it acts as a quality indicator. This investigative research thesis presents an online surface roughness prediction, based on the Adaptive Neuro-Fuzzy Inference System (ANFIS) model during Ultra-High Precision Diamond Turning (UHPDT) of Rapidly Solidified Aluminium (RSA-443) using water and kerosene as coolants. Based on the Taguchi L9 orthogonal array, the cutting parameters (spindle speed, depth of cut and feed rate) are varied at three levels. Acoustic Emission (AE) signals are detected during the UHPDT process using a piezoelectric sensor. Spindle speed, depth of cut, feed rate, AE root mean square, prominent frequency and peak rate are considered as model inputs in this thesis. The experimental results reveal that a better surface finish is obtained using water coolant in comparison to kerosene coolant. Mean Absolute Percentage Error (MAPE) based comparison between ANFIS and Response Surface Method (RSM) is carried out. In this study, the ANFIS model has a prediction accuracy of 79.42% and 69.40% on water-based and kerosene-based results respectively. The RSM model yields higher prediction accuracies of 98.59% and 95.55% on water-based and kerosene-based results respectively.
- Full Text:
- Date Issued: 2020
Synthesis, structure and in vitro anti-trypanosomal activity of non-toxic Arylpyrrole-Based Chalcone derivatives:
- Zulu, Ayanda I, Oderinlo, Ogunyemi O, Kruger, Cuan, Isaacs, Michelle, Hoppe, Heinrich C, Smith, Vincent J, Veale, Clinton G L, Khanye, Setshaba D
- Authors: Zulu, Ayanda I , Oderinlo, Ogunyemi O , Kruger, Cuan , Isaacs, Michelle , Hoppe, Heinrich C , Smith, Vincent J , Veale, Clinton G L , Khanye, Setshaba D
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179017 , vital:40096 , https://doi.org/10.3390/molecules25071668
- Description: With an intention of identifying chalcone derivatives exhibiting anti-protozoal activity, a cohort of relatively unexplored arylpyrrole-based chalcone derivatives were synthesized in moderate to good yields. The resultant compounds were evaluated in vitro for their potential activity against a cultured Trypanosoma brucei brucei 427 strain. Several compounds displayed mostly modest in vitro anti-trypanosomal activity with compounds 10e and 10h emerging as active candidates with IC50 values of 4.09 and 5.11 µM, respectively. More importantly, a concomitant assessment of their activity against a human cervix adenocarcinoma (HeLa) cell line revealed that these compounds are non-toxic.
- Full Text:
- Date Issued: 2020
- Authors: Zulu, Ayanda I , Oderinlo, Ogunyemi O , Kruger, Cuan , Isaacs, Michelle , Hoppe, Heinrich C , Smith, Vincent J , Veale, Clinton G L , Khanye, Setshaba D
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179017 , vital:40096 , https://doi.org/10.3390/molecules25071668
- Description: With an intention of identifying chalcone derivatives exhibiting anti-protozoal activity, a cohort of relatively unexplored arylpyrrole-based chalcone derivatives were synthesized in moderate to good yields. The resultant compounds were evaluated in vitro for their potential activity against a cultured Trypanosoma brucei brucei 427 strain. Several compounds displayed mostly modest in vitro anti-trypanosomal activity with compounds 10e and 10h emerging as active candidates with IC50 values of 4.09 and 5.11 µM, respectively. More importantly, a concomitant assessment of their activity against a human cervix adenocarcinoma (HeLa) cell line revealed that these compounds are non-toxic.
- Full Text:
- Date Issued: 2020
A case study of how a leader shaped the culture of an organisation during a post-merger integration
- Authors: Zozi, Vuyokazi
- Date: 2020
- Subjects: Corporate culture -- South Africa -- East London , Leadership -- South Africa -- East London , Organizational behavior -- South Africa -- East London , Strategic planning -- South Africa -- East London , Mission statements -- South Africa -- East London , Government accountability -- South Africa -- East London , Government corporations -- South Africa -- East London , Consolidation and merger of corporations -- South Africa -- East London , Consolidation and merger of corporations -- Management , Crisis management -- South Africa -- East London , Core competencies -- South Africa -- East London , Resource allocation -- South Africa -- East London , Personnel management -- South Africa -- East London , Communication in management -- South Africa -- East London , Qualitative research
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/146643 , vital:38544
- Description: This research took the form of a case study of the post-merger integration of a government organisation. The study had four objectives, namely to: (1) describe the cultural value of accountability; (2) analyse how strategic leadership and relational leadership roles were exercised to address post-merger integration challenges; (3) analyse how a leader applied selected primary mechanisms to shape organisational culture; (4) analyse how strategic and relational leadership complemented each other in addressing the challenges of post-merger integration and thereby shaping a culture of accountability; and (5) describe how some of the secondary articulation and reinforcing mechanisms supported the culture that was created through primary mechanisms. The literature reviewed, identified some of the critical challenges that are experienced in a post-merger integration, and highlighted the role of leadership in culture formation. The critical challenges that were identified are as follows: What is the vision and organisational purpose? How does the leader structure the organisation? What kind of culture does the leader need to create? How does the leader maintain trust and keep communication with employees? How does a leader build new core competences and develop human capital? Two leadership approaches were adopted, namely strategic and relational leadership. These two leadership approaches were selected because, based on a review of the literature, they appeared to address these post-integration challenges. The roles associated with strategic leadership that were investigated, were creating a vision and purpose for the organisation, developing core competences and developing human capital. From the perspective of relational leadership, this study was concerned with how a leader communicated through regular formal and informal dialogues to keep employees abreast of things, and how the leader built trust. In reviewing the literature linking leadership and culture, the work of Schein (2010) featured prominently. Schein (2010) referred to primary embedding mechanisms that create culture and secondary articulation and reinforcing mechanisms that reinforce or support the culture being created through the primary mechanisms. This study looked at how that happens, and hence six propositions were crafted from the literature. These propositions are as follows: (1) Formal dialogues between the leader and employees demonstrate what the leader pays attention to, measures and controls, which then clarifies what the employees are accountable for. (2) What the leader pays attention to, measures and controls during regular informal interactions between the leader and employees, contributes to strong mutual relationships between them, which promotes ownership and accountability amongst employees for their actions. (3) A leader who behaves consistently when handling critical incidents and organisational crises, is trusted by employees, who then act responsibly and take full responsibility for their actions, and even their mistakes. (4) A leader creates a vision and sense of purpose for the organisation through what he pays attention to, measures and controls, thereby clarifying for employees what they are required to do. (5) A leader who pays attention to developing the organisational core competence and allocates resources to it, instils confidence in his employees with regards to carrying out their own responsibilities. (6) A leader who develops human capital through the allocation of additional resources, thereby instilling confidence in employees who are willing and able to realise or take up their responsibilities. This research adopted a qualitative approach. Data was collected through conducting interviews and the analysis of relevant documents. A deductive thematic analysis of the data was used for the purpose of identifying, analysing and reporting patterns, or themes within the data collected. The research confirmed these propositions as being relevant to the case study. It also confirmed that strategic and relational leadership as reflected in the propositions have complemented one another in the successful implementation of the post-merger integration, thereby shaping a particular culture. It was concluded that the challenges associated with a post-merger integration could not have been addressed through only one of the leadership approaches. The findings of the study also recognised that an architectural role was also required. That is, in a merger, the structure has to be carefully designed and not taken for granted. It was therefore recognised as a critical leadership role. The study considers the implications of the findings and makes recommendations for managers of this organisation, as well as for other organisations that are engaging in a post-merger integration. It further outlines the limitations, delimitations as well as the contribution that the study has made to the body of knowledge. Some of the recommendations made for further research were to analyse how other primary mechanisms that were not part of the propositions may shape the organisational culture; and to research how architectural leadership roles combine with strategic and relational leadership to address post-merger integration challenges. Lastly, this study has explained how leadership, through various mechanisms, shaped a culture of accountability. Other studies can be done using a similar design with different theories of leadership and other mechanisms that apply to shaping other kinds of cultural values.
- Full Text:
- Date Issued: 2020
- Authors: Zozi, Vuyokazi
- Date: 2020
- Subjects: Corporate culture -- South Africa -- East London , Leadership -- South Africa -- East London , Organizational behavior -- South Africa -- East London , Strategic planning -- South Africa -- East London , Mission statements -- South Africa -- East London , Government accountability -- South Africa -- East London , Government corporations -- South Africa -- East London , Consolidation and merger of corporations -- South Africa -- East London , Consolidation and merger of corporations -- Management , Crisis management -- South Africa -- East London , Core competencies -- South Africa -- East London , Resource allocation -- South Africa -- East London , Personnel management -- South Africa -- East London , Communication in management -- South Africa -- East London , Qualitative research
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/146643 , vital:38544
- Description: This research took the form of a case study of the post-merger integration of a government organisation. The study had four objectives, namely to: (1) describe the cultural value of accountability; (2) analyse how strategic leadership and relational leadership roles were exercised to address post-merger integration challenges; (3) analyse how a leader applied selected primary mechanisms to shape organisational culture; (4) analyse how strategic and relational leadership complemented each other in addressing the challenges of post-merger integration and thereby shaping a culture of accountability; and (5) describe how some of the secondary articulation and reinforcing mechanisms supported the culture that was created through primary mechanisms. The literature reviewed, identified some of the critical challenges that are experienced in a post-merger integration, and highlighted the role of leadership in culture formation. The critical challenges that were identified are as follows: What is the vision and organisational purpose? How does the leader structure the organisation? What kind of culture does the leader need to create? How does the leader maintain trust and keep communication with employees? How does a leader build new core competences and develop human capital? Two leadership approaches were adopted, namely strategic and relational leadership. These two leadership approaches were selected because, based on a review of the literature, they appeared to address these post-integration challenges. The roles associated with strategic leadership that were investigated, were creating a vision and purpose for the organisation, developing core competences and developing human capital. From the perspective of relational leadership, this study was concerned with how a leader communicated through regular formal and informal dialogues to keep employees abreast of things, and how the leader built trust. In reviewing the literature linking leadership and culture, the work of Schein (2010) featured prominently. Schein (2010) referred to primary embedding mechanisms that create culture and secondary articulation and reinforcing mechanisms that reinforce or support the culture being created through the primary mechanisms. This study looked at how that happens, and hence six propositions were crafted from the literature. These propositions are as follows: (1) Formal dialogues between the leader and employees demonstrate what the leader pays attention to, measures and controls, which then clarifies what the employees are accountable for. (2) What the leader pays attention to, measures and controls during regular informal interactions between the leader and employees, contributes to strong mutual relationships between them, which promotes ownership and accountability amongst employees for their actions. (3) A leader who behaves consistently when handling critical incidents and organisational crises, is trusted by employees, who then act responsibly and take full responsibility for their actions, and even their mistakes. (4) A leader creates a vision and sense of purpose for the organisation through what he pays attention to, measures and controls, thereby clarifying for employees what they are required to do. (5) A leader who pays attention to developing the organisational core competence and allocates resources to it, instils confidence in his employees with regards to carrying out their own responsibilities. (6) A leader who develops human capital through the allocation of additional resources, thereby instilling confidence in employees who are willing and able to realise or take up their responsibilities. This research adopted a qualitative approach. Data was collected through conducting interviews and the analysis of relevant documents. A deductive thematic analysis of the data was used for the purpose of identifying, analysing and reporting patterns, or themes within the data collected. The research confirmed these propositions as being relevant to the case study. It also confirmed that strategic and relational leadership as reflected in the propositions have complemented one another in the successful implementation of the post-merger integration, thereby shaping a particular culture. It was concluded that the challenges associated with a post-merger integration could not have been addressed through only one of the leadership approaches. The findings of the study also recognised that an architectural role was also required. That is, in a merger, the structure has to be carefully designed and not taken for granted. It was therefore recognised as a critical leadership role. The study considers the implications of the findings and makes recommendations for managers of this organisation, as well as for other organisations that are engaging in a post-merger integration. It further outlines the limitations, delimitations as well as the contribution that the study has made to the body of knowledge. Some of the recommendations made for further research were to analyse how other primary mechanisms that were not part of the propositions may shape the organisational culture; and to research how architectural leadership roles combine with strategic and relational leadership to address post-merger integration challenges. Lastly, this study has explained how leadership, through various mechanisms, shaped a culture of accountability. Other studies can be done using a similar design with different theories of leadership and other mechanisms that apply to shaping other kinds of cultural values.
- Full Text:
- Date Issued: 2020
Synthesis and characterization of binary and ternary palladium alloys for use as alternative counter electrode catalysts in dye sensitized solar cells
- Authors: Zingwe, Nyengerai Hillary
- Date: 2020
- Subjects: Electrocatalysis Chemistry
- Language: English
- Type: Thesis , Doctoral , PhD (Chemistry)
- Identifier: http://hdl.handle.net/10353/18513 , vital:42580
- Description: The dye sensitized solar cell counter electrode facilitates the regeneration of the dye molecules thereby ensuring the provision of higher sunlight to electricity conversion efficiency. The standard platinum electrode suffers from low efficiency due to corrosion by the redox mediator as well as being extremely expensive due to high demand. As an alternative this research study illustrates the efforts undertaken to replace the standard platinum counter electrode with palladium alloy counter electrodes. Application of palladium alloys ensures sustenance of high catalytic activity by palladium which is as effective as platinum. Although palladium is equally as expensive as platinum, its application in the form of alloys minimizes the amount required to produce an effective counter electrode to 0.001-0.004 moles thereby ensuring the provision of high efficiency at a lower cost. Furthermore, charge transfer from the other alloyed elements to the palladium atom increases active sites leading to higher catalytic activity than platinum. Additionally, changes in crystal structure due to alloying enhances resistance to corrosion thus enabling the longevity of the alloy counter electrode in the electrolyte ___________________________________________________________________________ Electrochemical analysis was conducted to determine the catalytic functionality of the developed alloys in cobalt, ferrocene and iodine redox mediators. The binary (PdNi-reduced graphene oxide (rGO) and PdCo-rGO) and ternary (PdNiCo-rGO) palladium alloys were fabricated via a hydrothermal method. In order to determine the composition which could provide the maximum activity, optimization was conducted through variation of the molar ratios of the precursor solutions. The properties of the synthesized palladium alloys were determined using various techniques including x-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The developed alloys were observed to comprise of palladium, nickel, cobalt, and carbon atoms. The particles were spherical in nature for all the unsupported alloys with the carbon supported alloys exhibiting spherical particle wholly surrounded by graphene sheets. Cyclic voltammetry and electrochemical impedance spectroscopy analysis showed that the carbon supported alloys PdNi-rGO, PdCo-rGO and PdNiCo-rGO produced the highest catalytic activities due to the synergy between their respective alloys and the incorporated reduced graphene oxide. The high catalytic effectiveness of these alloys yielded power conversion efficiency in the order PdNiCo-rGO (9.01) > PdNi-rGO (8.4.%) > PdCo-rGO (6.56%) > Pt (5.7%) which were better than the platinum efficiency in the cobalt redox mediator. The higher efficiency in the cobalt redox mediator relative to the iodine electrolyte illustrates that they are viable alternatives to the, corrosive and volatile iodine. Obtained results show that, the high recombination rates between the photogenerated electrons and the oxidized dye molecule which have been reported to reduce power conversion efficiency in one electron redox mediators did not affect the performance of the cell. However, these higher recombination rates affected the ferrocene electrolyte leading to extremely poor efficiency metrics. The obtained results indicated that reduced graphene oxide supported PdNi-rGO, PdNiCo-rGO as well as the unsupported PdNi3 alloys could successfully be implemented as substitutes to the platinum counter electrode in dye sensitized solar cells. The application of the palladium alloys is vital for improving stability and power conversion efficiency, as well as reducing cost.
- Full Text:
- Date Issued: 2020
- Authors: Zingwe, Nyengerai Hillary
- Date: 2020
- Subjects: Electrocatalysis Chemistry
- Language: English
- Type: Thesis , Doctoral , PhD (Chemistry)
- Identifier: http://hdl.handle.net/10353/18513 , vital:42580
- Description: The dye sensitized solar cell counter electrode facilitates the regeneration of the dye molecules thereby ensuring the provision of higher sunlight to electricity conversion efficiency. The standard platinum electrode suffers from low efficiency due to corrosion by the redox mediator as well as being extremely expensive due to high demand. As an alternative this research study illustrates the efforts undertaken to replace the standard platinum counter electrode with palladium alloy counter electrodes. Application of palladium alloys ensures sustenance of high catalytic activity by palladium which is as effective as platinum. Although palladium is equally as expensive as platinum, its application in the form of alloys minimizes the amount required to produce an effective counter electrode to 0.001-0.004 moles thereby ensuring the provision of high efficiency at a lower cost. Furthermore, charge transfer from the other alloyed elements to the palladium atom increases active sites leading to higher catalytic activity than platinum. Additionally, changes in crystal structure due to alloying enhances resistance to corrosion thus enabling the longevity of the alloy counter electrode in the electrolyte ___________________________________________________________________________ Electrochemical analysis was conducted to determine the catalytic functionality of the developed alloys in cobalt, ferrocene and iodine redox mediators. The binary (PdNi-reduced graphene oxide (rGO) and PdCo-rGO) and ternary (PdNiCo-rGO) palladium alloys were fabricated via a hydrothermal method. In order to determine the composition which could provide the maximum activity, optimization was conducted through variation of the molar ratios of the precursor solutions. The properties of the synthesized palladium alloys were determined using various techniques including x-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The developed alloys were observed to comprise of palladium, nickel, cobalt, and carbon atoms. The particles were spherical in nature for all the unsupported alloys with the carbon supported alloys exhibiting spherical particle wholly surrounded by graphene sheets. Cyclic voltammetry and electrochemical impedance spectroscopy analysis showed that the carbon supported alloys PdNi-rGO, PdCo-rGO and PdNiCo-rGO produced the highest catalytic activities due to the synergy between their respective alloys and the incorporated reduced graphene oxide. The high catalytic effectiveness of these alloys yielded power conversion efficiency in the order PdNiCo-rGO (9.01) > PdNi-rGO (8.4.%) > PdCo-rGO (6.56%) > Pt (5.7%) which were better than the platinum efficiency in the cobalt redox mediator. The higher efficiency in the cobalt redox mediator relative to the iodine electrolyte illustrates that they are viable alternatives to the, corrosive and volatile iodine. Obtained results show that, the high recombination rates between the photogenerated electrons and the oxidized dye molecule which have been reported to reduce power conversion efficiency in one electron redox mediators did not affect the performance of the cell. However, these higher recombination rates affected the ferrocene electrolyte leading to extremely poor efficiency metrics. The obtained results indicated that reduced graphene oxide supported PdNi-rGO, PdNiCo-rGO as well as the unsupported PdNi3 alloys could successfully be implemented as substitutes to the platinum counter electrode in dye sensitized solar cells. The application of the palladium alloys is vital for improving stability and power conversion efficiency, as well as reducing cost.
- Full Text:
- Date Issued: 2020
Visualising Chinese presence: an analysis of the contemporary arts of Zambia and Zimbabwe
- Authors: Zhang, Lifang
- Date: 2020
- Subjects: Art, Modern -- 21st century , Art, Modern -- 21st century -- Chinese influences , China -- Relations -- Zambia , China -- Relations -- Zimbabwe , Art and society -- Zambia , Social practice (Art) -- Zambia , Art and globalization -- Zambia , Art and society -- Zimbabwe , Social practice (Art) -- Zimbabwe , Art and globalization -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/146618 , vital:38542
- Description: With the revival and rapid growth of relations between China and African countries in the present century, the “China-Africa relationship” has become a topic of close attention globally and the media and politicians have been dominating the mainstream discourses with dichotomised narratives. China-Africa engagement has also spurred academic research, most of which is oriented toward large-scale economic, political, and strategic concerns. In this context, it is significant to conduct in-depth research exploring specific engagement between Chinese and African people on the ground. Contemporary artists based in Africa have started to represent, through artworks and performances, their experiences and expressions of relations between China and various African countries. However, an examination of twenty-first century connections between Africa and China in relation to the contemporary visual arts is a new area of study and only a limited number of scholarly works exist. To contribute to the research in this area, this thesis explores the ways in which artists engage with specific realities and lived-experiences of Chinese presence through their artistic practices, with a focus on a selection of artists from Zambia and Zimbabwe. Through visual analysis, interviews and field work, this thesis provides a systematic investigation of contemporary arts of Zambia and Zimbabwe in relation to Africa- China encounters, engaging with four aspects: the discursive field, the material presence, individual experiences of encounters, and the broader relational connections within the arts. This thesis argues that, motivated by the histories and realities of African societies, artists from Zambia and Zimbabwe, through their artistic practices, form part of the Africa-China engagement and insert their agencies in the south-south relations between Africans and Chinese. Therefore, this thesis demonstrates the value in approaching the broader discussion on Africa-China engagements from the perspective of contemporary art, arguing that, with the social concerns of the artists and the expressive capacity of creative forms, visual arts are able to embrace diversity, dynamics, complexities and contradictions, and, therefore, can develop the topic beyond the stereotypical narratives about Africa-China relations to a more nuanced understanding of African-Chinese encounters in specific contexts.
- Full Text:
- Date Issued: 2020
- Authors: Zhang, Lifang
- Date: 2020
- Subjects: Art, Modern -- 21st century , Art, Modern -- 21st century -- Chinese influences , China -- Relations -- Zambia , China -- Relations -- Zimbabwe , Art and society -- Zambia , Social practice (Art) -- Zambia , Art and globalization -- Zambia , Art and society -- Zimbabwe , Social practice (Art) -- Zimbabwe , Art and globalization -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/146618 , vital:38542
- Description: With the revival and rapid growth of relations between China and African countries in the present century, the “China-Africa relationship” has become a topic of close attention globally and the media and politicians have been dominating the mainstream discourses with dichotomised narratives. China-Africa engagement has also spurred academic research, most of which is oriented toward large-scale economic, political, and strategic concerns. In this context, it is significant to conduct in-depth research exploring specific engagement between Chinese and African people on the ground. Contemporary artists based in Africa have started to represent, through artworks and performances, their experiences and expressions of relations between China and various African countries. However, an examination of twenty-first century connections between Africa and China in relation to the contemporary visual arts is a new area of study and only a limited number of scholarly works exist. To contribute to the research in this area, this thesis explores the ways in which artists engage with specific realities and lived-experiences of Chinese presence through their artistic practices, with a focus on a selection of artists from Zambia and Zimbabwe. Through visual analysis, interviews and field work, this thesis provides a systematic investigation of contemporary arts of Zambia and Zimbabwe in relation to Africa- China encounters, engaging with four aspects: the discursive field, the material presence, individual experiences of encounters, and the broader relational connections within the arts. This thesis argues that, motivated by the histories and realities of African societies, artists from Zambia and Zimbabwe, through their artistic practices, form part of the Africa-China engagement and insert their agencies in the south-south relations between Africans and Chinese. Therefore, this thesis demonstrates the value in approaching the broader discussion on Africa-China engagements from the perspective of contemporary art, arguing that, with the social concerns of the artists and the expressive capacity of creative forms, visual arts are able to embrace diversity, dynamics, complexities and contradictions, and, therefore, can develop the topic beyond the stereotypical narratives about Africa-China relations to a more nuanced understanding of African-Chinese encounters in specific contexts.
- Full Text:
- Date Issued: 2020
The implementation of the back to basics programme by municipalities: a case of Raymond Mhlaba Municipality
- Zengethwa, Noluvuyo Precious
- Authors: Zengethwa, Noluvuyo Precious
- Date: 2020
- Subjects: Leadership Management
- Language: English
- Type: Thesis , Masters , MPA
- Identifier: http://hdl.handle.net/10353/18941 , vital:43001
- Description: The aim of the study was to investigate the implementation of the Back-to-Basics (B2B) programme in Raymond Mhlaba Municipality. The study used qualitative research design and data was collected using in-depth interviews. The finding of the study revealed that the municipality was able to sufficiently implement the appropriate B2B programme in the community areas. Moreover, the findings identified corruption and mismanagement of funds, improper understanding of the municipality’s IDP and the roles of different government departments, poor communication skills between the municipality ward councillors and the community members, as well as poor service delivery as some of the challenges faced by Raymond Mhlaba Municipality in implementing the Back-To-Basics programmes. Importantly, in respective community areas, the findings revealed that water crises, empty promises and unrealistic/fake promises are some of the negative impacts the community members experienced during the implementation of the B2B programme, which brought little growth and development to the communities. Besides, the findings revealed that the implementation of this programme created employment opportunities for the unemployed youths in the communities. The study, however, concluded that the municipality is not doing enough in the implementation of B2B programme as many communities still complain of poor service delivery. Hence, for effectiveness in the implementation of B2B programme, it is important that the municipality delegates powers to the ward councillors. Furthermore, municipality management needs to refrain from making empty promises to the communities, they must be honest and deliver qualitative services to communities. However, community members should show signs of appreciation to all municipal activities, as well be supportive and ii show lots of interest and willingness attending the municipality’s manifestoes. Finally, the municipality management should ensure transparency, effective communication with the community members, provision of good service delivery, fulfilment of promises, honesty, proper budgetary allocation and spending, effective monitoring and evaluation of the municipal officials, as well as avoiding of nepotism in awarding tenders for the purpose of achieving a smooth running of the municipality.
- Full Text:
- Date Issued: 2020
- Authors: Zengethwa, Noluvuyo Precious
- Date: 2020
- Subjects: Leadership Management
- Language: English
- Type: Thesis , Masters , MPA
- Identifier: http://hdl.handle.net/10353/18941 , vital:43001
- Description: The aim of the study was to investigate the implementation of the Back-to-Basics (B2B) programme in Raymond Mhlaba Municipality. The study used qualitative research design and data was collected using in-depth interviews. The finding of the study revealed that the municipality was able to sufficiently implement the appropriate B2B programme in the community areas. Moreover, the findings identified corruption and mismanagement of funds, improper understanding of the municipality’s IDP and the roles of different government departments, poor communication skills between the municipality ward councillors and the community members, as well as poor service delivery as some of the challenges faced by Raymond Mhlaba Municipality in implementing the Back-To-Basics programmes. Importantly, in respective community areas, the findings revealed that water crises, empty promises and unrealistic/fake promises are some of the negative impacts the community members experienced during the implementation of the B2B programme, which brought little growth and development to the communities. Besides, the findings revealed that the implementation of this programme created employment opportunities for the unemployed youths in the communities. The study, however, concluded that the municipality is not doing enough in the implementation of B2B programme as many communities still complain of poor service delivery. Hence, for effectiveness in the implementation of B2B programme, it is important that the municipality delegates powers to the ward councillors. Furthermore, municipality management needs to refrain from making empty promises to the communities, they must be honest and deliver qualitative services to communities. However, community members should show signs of appreciation to all municipal activities, as well be supportive and ii show lots of interest and willingness attending the municipality’s manifestoes. Finally, the municipality management should ensure transparency, effective communication with the community members, provision of good service delivery, fulfilment of promises, honesty, proper budgetary allocation and spending, effective monitoring and evaluation of the municipal officials, as well as avoiding of nepotism in awarding tenders for the purpose of achieving a smooth running of the municipality.
- Full Text:
- Date Issued: 2020
Development framework in the Mdantsane central business district
- Authors: Zenani, Pumzile
- Date: 2020
- Subjects: Central business district -- South Africa -- East London , City planning -- South Africa -- East London Public utilities -- Management
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/47292 , vital:39840
- Description: The study sought to investigate a development performance and management of Mdantsane CBD. The performance measurement framework may enhance the chances of economic success in the CBD. The study was conducted by means of a review of related literature and by conducting an empirical study. The empirical study was conducted using a quantitative approach by distributing research questionnaires to members falling within the sample population. The primary objective of the study was to develop a framework for perceived enhanced development for the Mdantsane CBD. A descriptive survey was conducted among the population within Mdantsane Township. The framework includes strategic factors of planning during apartheid era, reviewed strategic planning during democratic era and it provides an understanding of the current spatial and physical characteristics of the study area. Key issues such as spatial planning, infrastructure, environment, health, safety, economics and management of the CBD were also identified. Findings were based on the survey’s results from the community members. Findings suggest that the following variables: strategic factors (democratic); spatial development framework and infrastructure implementation; budget alignment; PESTEL factors (Political, Economic, Social, Technological, Ecological and Legal); environmental health and safety, transport and transport engineering, project management (body of knowledge) and the National Development Plan positively influenced the perceived enhanced development of Mdantsane CBD. All these variables were identified in the empirical framework affecting the perceived enhanced development of Mdantsane CBD. This study may contribute to the South African spatial and development planning body of knowledge by addressing factors which are faced by planners in development of the settlements.
- Full Text:
- Date Issued: 2020
- Authors: Zenani, Pumzile
- Date: 2020
- Subjects: Central business district -- South Africa -- East London , City planning -- South Africa -- East London Public utilities -- Management
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/47292 , vital:39840
- Description: The study sought to investigate a development performance and management of Mdantsane CBD. The performance measurement framework may enhance the chances of economic success in the CBD. The study was conducted by means of a review of related literature and by conducting an empirical study. The empirical study was conducted using a quantitative approach by distributing research questionnaires to members falling within the sample population. The primary objective of the study was to develop a framework for perceived enhanced development for the Mdantsane CBD. A descriptive survey was conducted among the population within Mdantsane Township. The framework includes strategic factors of planning during apartheid era, reviewed strategic planning during democratic era and it provides an understanding of the current spatial and physical characteristics of the study area. Key issues such as spatial planning, infrastructure, environment, health, safety, economics and management of the CBD were also identified. Findings were based on the survey’s results from the community members. Findings suggest that the following variables: strategic factors (democratic); spatial development framework and infrastructure implementation; budget alignment; PESTEL factors (Political, Economic, Social, Technological, Ecological and Legal); environmental health and safety, transport and transport engineering, project management (body of knowledge) and the National Development Plan positively influenced the perceived enhanced development of Mdantsane CBD. All these variables were identified in the empirical framework affecting the perceived enhanced development of Mdantsane CBD. This study may contribute to the South African spatial and development planning body of knowledge by addressing factors which are faced by planners in development of the settlements.
- Full Text:
- Date Issued: 2020
Developing a Machine Learning Algorithm for Outdoor Scene Image Segmentation
- Authors: Zangwa, Yamkela
- Date: 2020
- Subjects: Computational intelligence Computer science
- Language: English
- Type: Thesis , Masters , MSc (Computer Science )
- Identifier: http://hdl.handle.net/10353/12087 , vital:39150
- Description: Image segmentation is one of the major problems in image processing, computer vision and machine learning fields. The main reason for image segmentation existence is to reduce the gap between computer vision and human vision by training computers with different data. Outdoor image segmentation and classification has become very important in the field of computer vision with its applications in woodland-surveillance, defence and security. The task of assigning an input image to one class from a fixed set of categories seem to be a major problem in image segmentation. The main question that has been addressed in this research is how outdoor image classification algorithms can be improved using Region-based Convolutional Neural Network (R-CNN) architecture. There has been no one segmentation method that works best on any given problem. To determine the best segmentation method for a certain dataset, various tests have to be done in order to achieve the best performance. However deep learning models have often achieved increasing success due to the availability of massive datasets and the expanding model depth and parameterisation. In this research Convolutional Neural Network architecture is used in trying to improve the implementation of outdoor scene image segmentation algorithms, empirical research method was used to answer questions about existing image segmentation algorithms and the techniques used to achieve the best performance. Outdoor scene images were trained on a pre-trained region-based convolutional neural network with Visual Geometric Group-16 (VGG-16) architecture. A pre-trained R-CNN model was retrained on five different sample data, the samples had different sizes. Sample size increased from sample one to five, to increase the size on the last two samples the data was duplicated. 21 test images were used to evaluate all the models. Researchers has shown that deep learning methods perform better in image segmentation because of the increase and availability of datasets. The duplication of images did not yield the best results; however, the model performed well on the first three samples.
- Full Text:
- Date Issued: 2020
- Authors: Zangwa, Yamkela
- Date: 2020
- Subjects: Computational intelligence Computer science
- Language: English
- Type: Thesis , Masters , MSc (Computer Science )
- Identifier: http://hdl.handle.net/10353/12087 , vital:39150
- Description: Image segmentation is one of the major problems in image processing, computer vision and machine learning fields. The main reason for image segmentation existence is to reduce the gap between computer vision and human vision by training computers with different data. Outdoor image segmentation and classification has become very important in the field of computer vision with its applications in woodland-surveillance, defence and security. The task of assigning an input image to one class from a fixed set of categories seem to be a major problem in image segmentation. The main question that has been addressed in this research is how outdoor image classification algorithms can be improved using Region-based Convolutional Neural Network (R-CNN) architecture. There has been no one segmentation method that works best on any given problem. To determine the best segmentation method for a certain dataset, various tests have to be done in order to achieve the best performance. However deep learning models have often achieved increasing success due to the availability of massive datasets and the expanding model depth and parameterisation. In this research Convolutional Neural Network architecture is used in trying to improve the implementation of outdoor scene image segmentation algorithms, empirical research method was used to answer questions about existing image segmentation algorithms and the techniques used to achieve the best performance. Outdoor scene images were trained on a pre-trained region-based convolutional neural network with Visual Geometric Group-16 (VGG-16) architecture. A pre-trained R-CNN model was retrained on five different sample data, the samples had different sizes. Sample size increased from sample one to five, to increase the size on the last two samples the data was duplicated. 21 test images were used to evaluate all the models. Researchers has shown that deep learning methods perform better in image segmentation because of the increase and availability of datasets. The duplication of images did not yield the best results; however, the model performed well on the first three samples.
- Full Text:
- Date Issued: 2020
Experiences of community service nurses regarding supervision and support from professional nurses in primary health care clinics in Nelson Mandela Bay
- Authors: Zambodla, Ayanda
- Date: 2020
- Subjects: Primary health care -- South Africa
- Language: English
- Type: Thesis , Masters , MCur
- Identifier: http://hdl.handle.net/10948/46456 , vital:39604
- Description: Community servicenursesinSouthAfricaarenewly qualified nurses who have to undertake a one-year community service rotation in public healthcare facility. Recently qualified, they are not yet competent to work alone and require supervision Theobjectiveofthisstudywastoexploreanddescribetheexperiencesofcommunity service nurses with regards to the supervision and support they received from professional nurses at primary healthcare clinics inNelsonMandelaBay.The researcher utilised a qualitative research approach, with an explorative, descriptive and contextual research design inorder to achieve the objectives of this study. The research population comprised community service nurses who had completed their one-year community serviceduringthe2016-2017cycleinaprimary healthcarefacilityinNelsonMandelaBay.Purposivesamplingwasusedtoselectthe research sample. Data collection was done by conducting 10semi-structured interviews. Descriptive field notes supplemented the data. Tesch’smethod of qualitative data analysis was employed to analyse the data. Ethical considerations were applied throughout the study. Trustworthiness of the study was maintained by applyingGuba’s criteria of credibility, transferability, dependability and confirmability. Two main themes emerged from the study. Theme1 focused on the participant's experiences regarding the diverse needs related to the community service placement at primary healthcare clinics. Theme2 related to the participants expressed experiences with regard to social interaction during community service at primary healthcare clinics. The findings of the study enabled recommendations to be made for nursing practice, education and research.
- Full Text:
- Date Issued: 2020
- Authors: Zambodla, Ayanda
- Date: 2020
- Subjects: Primary health care -- South Africa
- Language: English
- Type: Thesis , Masters , MCur
- Identifier: http://hdl.handle.net/10948/46456 , vital:39604
- Description: Community servicenursesinSouthAfricaarenewly qualified nurses who have to undertake a one-year community service rotation in public healthcare facility. Recently qualified, they are not yet competent to work alone and require supervision Theobjectiveofthisstudywastoexploreanddescribetheexperiencesofcommunity service nurses with regards to the supervision and support they received from professional nurses at primary healthcare clinics inNelsonMandelaBay.The researcher utilised a qualitative research approach, with an explorative, descriptive and contextual research design inorder to achieve the objectives of this study. The research population comprised community service nurses who had completed their one-year community serviceduringthe2016-2017cycleinaprimary healthcarefacilityinNelsonMandelaBay.Purposivesamplingwasusedtoselectthe research sample. Data collection was done by conducting 10semi-structured interviews. Descriptive field notes supplemented the data. Tesch’smethod of qualitative data analysis was employed to analyse the data. Ethical considerations were applied throughout the study. Trustworthiness of the study was maintained by applyingGuba’s criteria of credibility, transferability, dependability and confirmability. Two main themes emerged from the study. Theme1 focused on the participant's experiences regarding the diverse needs related to the community service placement at primary healthcare clinics. Theme2 related to the participants expressed experiences with regard to social interaction during community service at primary healthcare clinics. The findings of the study enabled recommendations to be made for nursing practice, education and research.
- Full Text:
- Date Issued: 2020
Learning about volunteering: an exploration of literacy volunteers' experiences
- Authors: Yendall, Kaitlin Amy
- Date: 2020
- Subjects: Literacy -- Study and teaching -- South Africa , Literacy programs -- South Africa , Voluntarism -- South Africa , Volunteer workers in community development -- Training of , Service learning , Language and education -- South Africa , Language arts (Primary) , English language -- Study and teaching (Elementary) , Volunteer workers in Education -- Training of
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/138336 , vital:37623
- Description: After almost 25 years of democracy in South Africa, not everyone has access to the same quality education. The responsibility of creating a literate society however cannot rely on the national government and schools alone, but instead needs to fall on the shoulders of various stakeholders. Volunteers in particular have an important role to play in remedying the current literacy crisis experienced in South Africa. This study takes the form of a case study approach and examines the experiences of Project Read literacy volunteers. A telephonic survey and two focus group discussions were conducted in order to determine who it is that volunteers for the programme; what prompts these particular individuals to volunteer; the perceived benefits of volunteering; and how volunteers report on their volunteering experiences. Although the Project Read programme is focused on the early literacy development of learners, volunteers seemed to undergo a developmental process themselves – something they had not anticipated at the start of their volunteering journey. This study illustrates the power of meaningful relationships in breaking down artificial categories and in bringing about important change with regards to the perceptions and attitudes of individuals towards community engagement. It is hoped that the data generated through this study will assist in recruiting and retaining more literacy volunteers through feedback to the NGO. In this way more children will be assisted to enhance their literacy competencies, from which they can build and achieve.
- Full Text:
- Date Issued: 2020
- Authors: Yendall, Kaitlin Amy
- Date: 2020
- Subjects: Literacy -- Study and teaching -- South Africa , Literacy programs -- South Africa , Voluntarism -- South Africa , Volunteer workers in community development -- Training of , Service learning , Language and education -- South Africa , Language arts (Primary) , English language -- Study and teaching (Elementary) , Volunteer workers in Education -- Training of
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/138336 , vital:37623
- Description: After almost 25 years of democracy in South Africa, not everyone has access to the same quality education. The responsibility of creating a literate society however cannot rely on the national government and schools alone, but instead needs to fall on the shoulders of various stakeholders. Volunteers in particular have an important role to play in remedying the current literacy crisis experienced in South Africa. This study takes the form of a case study approach and examines the experiences of Project Read literacy volunteers. A telephonic survey and two focus group discussions were conducted in order to determine who it is that volunteers for the programme; what prompts these particular individuals to volunteer; the perceived benefits of volunteering; and how volunteers report on their volunteering experiences. Although the Project Read programme is focused on the early literacy development of learners, volunteers seemed to undergo a developmental process themselves – something they had not anticipated at the start of their volunteering journey. This study illustrates the power of meaningful relationships in breaking down artificial categories and in bringing about important change with regards to the perceptions and attitudes of individuals towards community engagement. It is hoped that the data generated through this study will assist in recruiting and retaining more literacy volunteers through feedback to the NGO. In this way more children will be assisted to enhance their literacy competencies, from which they can build and achieve.
- Full Text:
- Date Issued: 2020
National Wool Growers Association programme for communal farmers in Amahlathi local Municipality
- Authors: Yeki, Precious Nomantande
- Date: 2020
- Subjects: Farmers -- South Africa -- Eastern Cape , Wool industry – South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/50676 , vital:42331
- Description: By 2030, the majority of the world's population will live in urban areas and the farming populations we see today will be less. For the foreseeable future, meeting the needs of the future means confronting the problems that small farmers face in their daily struggle. The South African experience in relation to the agricultural sector is still principally dualistic, comprising of the large-scale commercial farming dominated by white farmers as well as small-scale sectors dominated by black farmers and this is distinctive in the local context of writings on agricultural and rural development. As a result, the government has adopted various approaches to promote Transformation in the sector, with mixed results. The well-known are the agricultural development programmes and black farmer empowerment programmes which also include land reform. This paper reviews one of the agricultural development programmes which seek to empower small holder farmers. The study assesses the impact of the National Wool Growers Association (NWGA) Wool Programme on the communal farmers productivity and agricultural income in Amahlathi Local Municipality. The NWGA has been the custodian for transformation and it has been a good vehicle to represent all wool producers in South Africa. The research discovered that the programme has a positive influence on productivity and agricultural income, yet there is a room for improvement both for the NWGA and the government. It was highlighted that the programme offers extension services, infrastructure for shearing shed, wool and carcass competition, shearing training to both shearers and wool farmers. The study also found that women and youth need to be included, in the programme.
- Full Text:
- Date Issued: 2020
- Authors: Yeki, Precious Nomantande
- Date: 2020
- Subjects: Farmers -- South Africa -- Eastern Cape , Wool industry – South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/50676 , vital:42331
- Description: By 2030, the majority of the world's population will live in urban areas and the farming populations we see today will be less. For the foreseeable future, meeting the needs of the future means confronting the problems that small farmers face in their daily struggle. The South African experience in relation to the agricultural sector is still principally dualistic, comprising of the large-scale commercial farming dominated by white farmers as well as small-scale sectors dominated by black farmers and this is distinctive in the local context of writings on agricultural and rural development. As a result, the government has adopted various approaches to promote Transformation in the sector, with mixed results. The well-known are the agricultural development programmes and black farmer empowerment programmes which also include land reform. This paper reviews one of the agricultural development programmes which seek to empower small holder farmers. The study assesses the impact of the National Wool Growers Association (NWGA) Wool Programme on the communal farmers productivity and agricultural income in Amahlathi Local Municipality. The NWGA has been the custodian for transformation and it has been a good vehicle to represent all wool producers in South Africa. The research discovered that the programme has a positive influence on productivity and agricultural income, yet there is a room for improvement both for the NWGA and the government. It was highlighted that the programme offers extension services, infrastructure for shearing shed, wool and carcass competition, shearing training to both shearers and wool farmers. The study also found that women and youth need to be included, in the programme.
- Full Text:
- Date Issued: 2020
Job characteristics and organisational citizenship behaviour among employees in a previously disadvantaged South African university
- Authors: Yawethe, Thozama
- Date: 2020
- Subjects: Organizational behavior
- Language: English
- Type: Thesis , Masters , MCom (Industrial Psychology)
- Identifier: http://hdl.handle.net/10353/18952 , vital:43002
- Description: This study examined job characteristics and organisational citizenship behaviour among employees in a previously disadvantaged South African University. A structured questionnaire was used to collect data from 149 randomly selected participants. A 5-point Likert scale job characteristics survey by Hackman and Oldham (1975) was used to measure job characteristics while, a 5-point Likert scale by Lee and Allen (2002) on organisational citizenship behaviour was used to measure employee’s organisational citizenship behaviour. Different statistical techniques such as Spearman rho correlation technique and Regression analysis were used to analyse data. The results showed that task significance, skills variety, autonomy and feedback are significantly positively related to organisational citizenship behaviour. There was a non-significant negative relationship between task identity and organisational citizenship behaviour. A combination of two or more job characteristics dimensions were found to report a higher proportion of variance in organisational citizenship behaviour than any one job characteristic separately. The study, thus, recommends that managers must design employees’ jobs or tasks that are more meaningful to stimulate the display of organisational citizenship behaviour. Initiatives that stimulate the use of a variety of skills, promotes feedback, promote task significance and autonomy were suggested as solutions to stimulate the display of OCB. The prevalence of such dimensions on one’s job increase motivation and satisfaction therefore contributing positively towards organisational citizenship behaviour.
- Full Text:
- Date Issued: 2020
- Authors: Yawethe, Thozama
- Date: 2020
- Subjects: Organizational behavior
- Language: English
- Type: Thesis , Masters , MCom (Industrial Psychology)
- Identifier: http://hdl.handle.net/10353/18952 , vital:43002
- Description: This study examined job characteristics and organisational citizenship behaviour among employees in a previously disadvantaged South African University. A structured questionnaire was used to collect data from 149 randomly selected participants. A 5-point Likert scale job characteristics survey by Hackman and Oldham (1975) was used to measure job characteristics while, a 5-point Likert scale by Lee and Allen (2002) on organisational citizenship behaviour was used to measure employee’s organisational citizenship behaviour. Different statistical techniques such as Spearman rho correlation technique and Regression analysis were used to analyse data. The results showed that task significance, skills variety, autonomy and feedback are significantly positively related to organisational citizenship behaviour. There was a non-significant negative relationship between task identity and organisational citizenship behaviour. A combination of two or more job characteristics dimensions were found to report a higher proportion of variance in organisational citizenship behaviour than any one job characteristic separately. The study, thus, recommends that managers must design employees’ jobs or tasks that are more meaningful to stimulate the display of organisational citizenship behaviour. Initiatives that stimulate the use of a variety of skills, promotes feedback, promote task significance and autonomy were suggested as solutions to stimulate the display of OCB. The prevalence of such dimensions on one’s job increase motivation and satisfaction therefore contributing positively towards organisational citizenship behaviour.
- Full Text:
- Date Issued: 2020
Navigating Blackness in the African Diaspora
- Authors: Yates, Sarah
- Date: 2020
- Subjects: Ellison, Ralph. Invisible man , Everett, Percival. Erasure , Wicomb, Zoe. Playing in the light , Bulawayo, NoViolet. We need new names , Africans in literature , Race in literature , African fiction (English) -- History and criticism
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/145720 , vital:38461
- Description: This thesis offers a comparative reading of Ralph Ellison’s Invisible Man, Percival Everett’s Erasure, Zoë Wicomb’s Playing in the Light and NoViolet Bulawayo’s We Need New Names in order to explore the diversity of subjectivities included within the terms ‘African’ and ‘black’ and to argue for the necessity of renewed definitions of Africa(nness) and blackness which allow for diverse and fluid representations. The diverse historical and political contexts in which these novels are published, as well as the critical and theoretical discussions which surround them demonstrate an evolution in literary portrayals of identity politics. As the categories of race and nation become more fluid, so too do narrative forms. In particular, this thesis is interested in the textual strategies authors use to navigate the various ways in which depictions of blackness continue to be restricted by racism, stereotypes, and the dynamics of a global literary market. As portrayals and discussions of identity politics proliferate in popular culture, they become increasingly commodified, and therefore increasingly restricted by the market.
- Full Text:
- Date Issued: 2020
- Authors: Yates, Sarah
- Date: 2020
- Subjects: Ellison, Ralph. Invisible man , Everett, Percival. Erasure , Wicomb, Zoe. Playing in the light , Bulawayo, NoViolet. We need new names , Africans in literature , Race in literature , African fiction (English) -- History and criticism
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/145720 , vital:38461
- Description: This thesis offers a comparative reading of Ralph Ellison’s Invisible Man, Percival Everett’s Erasure, Zoë Wicomb’s Playing in the Light and NoViolet Bulawayo’s We Need New Names in order to explore the diversity of subjectivities included within the terms ‘African’ and ‘black’ and to argue for the necessity of renewed definitions of Africa(nness) and blackness which allow for diverse and fluid representations. The diverse historical and political contexts in which these novels are published, as well as the critical and theoretical discussions which surround them demonstrate an evolution in literary portrayals of identity politics. As the categories of race and nation become more fluid, so too do narrative forms. In particular, this thesis is interested in the textual strategies authors use to navigate the various ways in which depictions of blackness continue to be restricted by racism, stereotypes, and the dynamics of a global literary market. As portrayals and discussions of identity politics proliferate in popular culture, they become increasingly commodified, and therefore increasingly restricted by the market.
- Full Text:
- Date Issued: 2020
The archival turn: rereading the Guy Butler Collection in the National English Literary Museum
- Authors: Wyrill, Beth
- Date: 2020
- Subjects: National English Literary Museum (South Africa) , Butler, Guy, 1918-2001 , Archives -- South Africa , Archives -- Philosophy , Memory (Philosophy)
- Language: English
- Type: Thesis , Doctoral , PHD
- Identifier: http://hdl.handle.net/10962/145746 , vital:38463
- Description: This thesis takes as its theoretical springboard the ‘archival turn’ in South African historical studies, a moment that arguably reached its culmination in 2002 with the publication of Refiguring the Archive. The archival turn posits that, rather than using it as an unproblematic source of original material, scholars might begin to investigate the archive itself, including its processes of construction and organisation. This theoretical model also proposes that the archive might reflect the cultural beliefs and epistemologies common to the era in which it was set up. It seems that the time is ripe for a reconsideration of the insights gleaned from this academic moment in South Africa, given the recent contestation over the meanings of history and our cultural markers of heritage in the public domain, largely grouped under the term ‘Fallism.’ As such, a fresh look at South African museums, which in this country are often rooted in colonial practices of knowledge production, seems apt. This work uses the case of Guy Butler, founder of many South African English cultural institutes and arts bodies, as a conduit and lens for thinking through these problematics. One of Butler’s institutional ‘offspring,’ born from his overarching work on behalf of the English cultural and literary cause in South Africa in the twentieth century, is the National English Literary Museum (NELM). Investigating the founding context and practices of NELM is a useful way of exploring the impact of Butler’s life’s work on literary heritage in South Africa. Issues such as the way in which NELM and Grahamstown continue to signify as loci of thought and practice in the contemporary South African literary landscape will be addressed. The study draws extensively on the Butler collection at NELM, and spends much time investigating Butler’s positioning in a South African literary historical context in the twentieth century, to better understand the forces at work during the time of NELM’s coming-into-being. Derrida’s seminal work on the function of archives, in Archive Fever, is mined for a theoretical basis for the study, as is Deleuze and Guattari’s thought on how bodies (taking the NELM institution here to represent a ‘body’) form, change, and interact, explicated in the work A Thousand Plateaus. The study offers some insights into how the NELM archive was formed, and which forces continue to shape its work in the South African spheres of English literature and heritage.
- Full Text:
- Date Issued: 2020
- Authors: Wyrill, Beth
- Date: 2020
- Subjects: National English Literary Museum (South Africa) , Butler, Guy, 1918-2001 , Archives -- South Africa , Archives -- Philosophy , Memory (Philosophy)
- Language: English
- Type: Thesis , Doctoral , PHD
- Identifier: http://hdl.handle.net/10962/145746 , vital:38463
- Description: This thesis takes as its theoretical springboard the ‘archival turn’ in South African historical studies, a moment that arguably reached its culmination in 2002 with the publication of Refiguring the Archive. The archival turn posits that, rather than using it as an unproblematic source of original material, scholars might begin to investigate the archive itself, including its processes of construction and organisation. This theoretical model also proposes that the archive might reflect the cultural beliefs and epistemologies common to the era in which it was set up. It seems that the time is ripe for a reconsideration of the insights gleaned from this academic moment in South Africa, given the recent contestation over the meanings of history and our cultural markers of heritage in the public domain, largely grouped under the term ‘Fallism.’ As such, a fresh look at South African museums, which in this country are often rooted in colonial practices of knowledge production, seems apt. This work uses the case of Guy Butler, founder of many South African English cultural institutes and arts bodies, as a conduit and lens for thinking through these problematics. One of Butler’s institutional ‘offspring,’ born from his overarching work on behalf of the English cultural and literary cause in South Africa in the twentieth century, is the National English Literary Museum (NELM). Investigating the founding context and practices of NELM is a useful way of exploring the impact of Butler’s life’s work on literary heritage in South Africa. Issues such as the way in which NELM and Grahamstown continue to signify as loci of thought and practice in the contemporary South African literary landscape will be addressed. The study draws extensively on the Butler collection at NELM, and spends much time investigating Butler’s positioning in a South African literary historical context in the twentieth century, to better understand the forces at work during the time of NELM’s coming-into-being. Derrida’s seminal work on the function of archives, in Archive Fever, is mined for a theoretical basis for the study, as is Deleuze and Guattari’s thought on how bodies (taking the NELM institution here to represent a ‘body’) form, change, and interact, explicated in the work A Thousand Plateaus. The study offers some insights into how the NELM archive was formed, and which forces continue to shape its work in the South African spheres of English literature and heritage.
- Full Text:
- Date Issued: 2020
A holistic approach in understanding the effects of dietary protein sources on the growth and reproductive development of farmed abalone, Haliotis midae
- Wu, Yu
- Authors: Wu, Yu
- Date: 2020
- Subjects: Abalones -- Nutrition , Abalones -- Reproduction , Abalones -- Growth , Abalone culture , Haliotis midae -- Nutrition , Haliotis midae -- Reproduction , Haliotis midae -- Growth , Haliotis midae fisheries
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167719 , vital:41506
- Description: The combination of fishmeal and soya in the formulated feed of farmed South African abalone, Haliotis midae, not only improved abalone growth, but also the sustainability of the compound diets by reducing the reliance on fishmeal. However, the presence of soya produced larger gonads compared to those of abalone fed kelp or single-source protein diets. There is an increasing drive to control sexual maturation and reduce undesirable spawning events in farmed abalone. However, the reasons for the reported effects of soya inclusion on the reproductive development of farmed H. midae remain unresolved. The aim of this research was to use a combination of techniques to contribute to the understanding of the relationship between growth, reproductive and nutritional physiology of farmed H. midae fed diets of varying protein sources. These techniques included stable isotope analysis (SIA), fatty acid analysis, gonad histological assessments and haemolymph sexsteroid hormone analysis. The objectives were to examine the allocation of protein and nutritional components to somatic and reproductive tissues. This study also included the first attempt to investigate the role that sex steroid hormones play during gametogenesis. Abalone (40 – 50 g abalone-1) were fed one of four diets: either a single-source protein-based diet, i.e., (1) fishmeal-only (FM) or (2) soya-only (S), or a combination diet of (3) fishmeal-soya (FM S) or (4) fishmeal-sunflower meal (FM SM). Sampling occurred in 45-day intervals over one year. Dietary protein source had an effect on the growth of abalone, with enhancements in growth linked to the combination of fishmeal and a plant-protein source. The fishmeal ingredient was the most utilised protein source throughout the temporal changes in protein allocation into somatic and reproductive tissue, followed by soya and then sunflower meal. The mean whole- body mass of abalone was significantly influenced by an interaction between time and dietary treatment, with average whole-body mass changing differently over time between treatments (RM-ANOVA, F(24, 96) = 2.13, p = 0.005). Overall, abalone that were fed FM S had higher mean whole-body mass values than abalone that were fed the single-protein based diets, while abalone that were fed FM SM were similar to animals from all dietary treatments (RMANOVA, F(3, 12) = 5.75, p = 0.01). Male abalone had significantly higher gonad bulk index (GBI) values compared to females (RM-ANOVA, F(1, 24) = 49.03, p < 0.001) and this was independent of dietary treatment. Within each sex, female abalone fed the FM S diet (15.92 ± 1.88 mm3 g-1) had significantly higher GBI values than abalone fed S (9.76 ± 1.08 mm3 g-1), while abalone fed FM (11.96 ± 1.71 mm3 g-1) and FM SM (11.90 ± 0.80 mm3 g-1) were similar to abalone from all other dietary treatments (Tukey’s HSD, p < 0.05). Male abalone fed the FM S (21.59 ± 2.10 mm3 g-1) and FM SM diet (19.30 ± 2.63 mm3 g-1) had similar GBI values and they were significantly higher than in abalone fed the S diet (14.74 ± 1.27 mm3 g-1), while abalone fed FM S had significantly higher GBI values than abalone that consumed the FM diet (15.08 ±1.63mm3 g-1) ( Tukey’s HSD, p < 0.05). Although sunflower meal was poorly utilised, it produced similar overall growth to abalone that were fed the FM S diets. Yet, feed conversion ratio values were significantly lower for abalone fed FM S (1.30 ± 0.13) compared to those in the other three treatments, with ratios ranging from 1.65 – 1.72 over the one-year. The fatty acid compositions of the somatic and gonadal tissues were similar between treatments (PERMANOVA, p = 0.21), while fatty acid composition was influenced by sampling day, tissue type and abalone sex (PERMANOVA, p < 0.05). The essential fatty acids (EFAs) eicosadienoic acid and a-linolenic acid were present in abalone tissue, but they were not detected in the diets, suggesting the important role that an alternate food source (e.g. farmed abalone also had access to diatoms) may have played and the ability that H. midae may have in converting long-chain polyunsaturated fatty acids from C18 precursors. A change in the abundance of EFAs in the gonad tissue during highest and lowest GBI values suggested that arachidonic, eicosapentaenoic, g-linolenic and linoleic acid were important in females, while eicosapentaenoic, eicosadienoic and a-linolenic acid were important for male reproductive development. Dietary protein sources had an effect on the frequency distribution of maturity stages, where females that were fed FM S produced more ripe gonads and more males that were fed FM SM contained testes that showed signs of ripeness over the one-year study. Although dietary protein influenced the sex steroid concentrations in females and males, exhibiting fluctuations throughout the one-year period, no distinct pattern linked to gametogenesis were observed. The results from this study illustrate: (1) the importance of conducting laboratory studies when implementing SIA and mixing models in aquaculture nutrition; (2) conducting nutritional studies on mature, grow-out abalone; and (3) assessing the importance of naturally occurring diatoms in their diet and their contribution to growth and reproduction. The novel contribution of this research towards abalone nutritional physiology, the implications of these findings to industry as well as potential considerations for future studies were addressed.
- Full Text:
- Date Issued: 2020
- Authors: Wu, Yu
- Date: 2020
- Subjects: Abalones -- Nutrition , Abalones -- Reproduction , Abalones -- Growth , Abalone culture , Haliotis midae -- Nutrition , Haliotis midae -- Reproduction , Haliotis midae -- Growth , Haliotis midae fisheries
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167719 , vital:41506
- Description: The combination of fishmeal and soya in the formulated feed of farmed South African abalone, Haliotis midae, not only improved abalone growth, but also the sustainability of the compound diets by reducing the reliance on fishmeal. However, the presence of soya produced larger gonads compared to those of abalone fed kelp or single-source protein diets. There is an increasing drive to control sexual maturation and reduce undesirable spawning events in farmed abalone. However, the reasons for the reported effects of soya inclusion on the reproductive development of farmed H. midae remain unresolved. The aim of this research was to use a combination of techniques to contribute to the understanding of the relationship between growth, reproductive and nutritional physiology of farmed H. midae fed diets of varying protein sources. These techniques included stable isotope analysis (SIA), fatty acid analysis, gonad histological assessments and haemolymph sexsteroid hormone analysis. The objectives were to examine the allocation of protein and nutritional components to somatic and reproductive tissues. This study also included the first attempt to investigate the role that sex steroid hormones play during gametogenesis. Abalone (40 – 50 g abalone-1) were fed one of four diets: either a single-source protein-based diet, i.e., (1) fishmeal-only (FM) or (2) soya-only (S), or a combination diet of (3) fishmeal-soya (FM S) or (4) fishmeal-sunflower meal (FM SM). Sampling occurred in 45-day intervals over one year. Dietary protein source had an effect on the growth of abalone, with enhancements in growth linked to the combination of fishmeal and a plant-protein source. The fishmeal ingredient was the most utilised protein source throughout the temporal changes in protein allocation into somatic and reproductive tissue, followed by soya and then sunflower meal. The mean whole- body mass of abalone was significantly influenced by an interaction between time and dietary treatment, with average whole-body mass changing differently over time between treatments (RM-ANOVA, F(24, 96) = 2.13, p = 0.005). Overall, abalone that were fed FM S had higher mean whole-body mass values than abalone that were fed the single-protein based diets, while abalone that were fed FM SM were similar to animals from all dietary treatments (RMANOVA, F(3, 12) = 5.75, p = 0.01). Male abalone had significantly higher gonad bulk index (GBI) values compared to females (RM-ANOVA, F(1, 24) = 49.03, p < 0.001) and this was independent of dietary treatment. Within each sex, female abalone fed the FM S diet (15.92 ± 1.88 mm3 g-1) had significantly higher GBI values than abalone fed S (9.76 ± 1.08 mm3 g-1), while abalone fed FM (11.96 ± 1.71 mm3 g-1) and FM SM (11.90 ± 0.80 mm3 g-1) were similar to abalone from all other dietary treatments (Tukey’s HSD, p < 0.05). Male abalone fed the FM S (21.59 ± 2.10 mm3 g-1) and FM SM diet (19.30 ± 2.63 mm3 g-1) had similar GBI values and they were significantly higher than in abalone fed the S diet (14.74 ± 1.27 mm3 g-1), while abalone fed FM S had significantly higher GBI values than abalone that consumed the FM diet (15.08 ±1.63mm3 g-1) ( Tukey’s HSD, p < 0.05). Although sunflower meal was poorly utilised, it produced similar overall growth to abalone that were fed the FM S diets. Yet, feed conversion ratio values were significantly lower for abalone fed FM S (1.30 ± 0.13) compared to those in the other three treatments, with ratios ranging from 1.65 – 1.72 over the one-year. The fatty acid compositions of the somatic and gonadal tissues were similar between treatments (PERMANOVA, p = 0.21), while fatty acid composition was influenced by sampling day, tissue type and abalone sex (PERMANOVA, p < 0.05). The essential fatty acids (EFAs) eicosadienoic acid and a-linolenic acid were present in abalone tissue, but they were not detected in the diets, suggesting the important role that an alternate food source (e.g. farmed abalone also had access to diatoms) may have played and the ability that H. midae may have in converting long-chain polyunsaturated fatty acids from C18 precursors. A change in the abundance of EFAs in the gonad tissue during highest and lowest GBI values suggested that arachidonic, eicosapentaenoic, g-linolenic and linoleic acid were important in females, while eicosapentaenoic, eicosadienoic and a-linolenic acid were important for male reproductive development. Dietary protein sources had an effect on the frequency distribution of maturity stages, where females that were fed FM S produced more ripe gonads and more males that were fed FM SM contained testes that showed signs of ripeness over the one-year study. Although dietary protein influenced the sex steroid concentrations in females and males, exhibiting fluctuations throughout the one-year period, no distinct pattern linked to gametogenesis were observed. The results from this study illustrate: (1) the importance of conducting laboratory studies when implementing SIA and mixing models in aquaculture nutrition; (2) conducting nutritional studies on mature, grow-out abalone; and (3) assessing the importance of naturally occurring diatoms in their diet and their contribution to growth and reproduction. The novel contribution of this research towards abalone nutritional physiology, the implications of these findings to industry as well as potential considerations for future studies were addressed.
- Full Text:
- Date Issued: 2020
Poor whites and the post-apartheid labour market: a study of perceptions and experiences of work among residents in a homeless shelter in Johannesburg
- Authors: Wollnik, Nadjeschda
- Date: 2020
- Subjects: Poor whites -- South Africa , Poor whites -- South Africa -- Atitudes , Shelters for the homeless -- South Africa , Unemployed -- South Africa -- Attitudes , Unemployed -- South Africa , South Africa -- Social conditions -- 1994- , South Africa -- Economic conditions -- 1991-
- Language: English
- Type: text , Thesis , Masters , MSocSci
- Identifier: http://hdl.handle.net/10962/148540 , vital:38748
- Description: Despite historical precedents, poverty among white people in South Africa remains an anomaly and a paradox. Likewise, the perceptions of work and employment among poor (under- and unemployed) whites in contemporary South Africa have received scant attention in the scholarly literature. Using the conceptual frameworks of critical whiteness studies and segmented labour market theory – as a way of combining subjective and objective considerations – this research seeks to describe and explain the perceptions and experiences of the labour market among poor whites living in a homeless shelter in Johannesburg. Eight respondents were chosen for extended, in-depth interviews in an effort to develop a fine-grained understanding of the pre-existing circumstances that affected their access to information and thus shaped their choices in the labour market, as well as to ascertain what they believed to be the barriers that they face in the labour market. The findings varied, with most of the interviewees seeing ‘being white’ as the reason for their poverty and unemployment, while others exhibited some awareness of the role of their lack of skills and qualifications in their capacity to compete in higher segments of the labour market. The findings were also varied in the sense that not all interviewees experienced poverty in the same manner, with some having been part of the middle class prior to becoming poor, while others having been poor their entire lives. It was also found that class or socio-economic status seemed to have a greater impact than race on the labour market prospects of the interviewees. It is argued that the perceptions of these poor whites, which are informed by their lack of information about the workings of the labour market, rather than their lack of qualifications or their race, most affected their prospects in the labour market. The mechanisms they rely on when seeking employment reveal a poor knowledge of the local labour market and the ways in which they think their skillsets match up to the types of jobs they desire. The lack of understanding of the South African labour market and the policies that are in place to redress the legacies of apartheid are among the factors influencing the lack of success these poor whites are experiencing in their search for work.
- Full Text:
- Date Issued: 2020
- Authors: Wollnik, Nadjeschda
- Date: 2020
- Subjects: Poor whites -- South Africa , Poor whites -- South Africa -- Atitudes , Shelters for the homeless -- South Africa , Unemployed -- South Africa -- Attitudes , Unemployed -- South Africa , South Africa -- Social conditions -- 1994- , South Africa -- Economic conditions -- 1991-
- Language: English
- Type: text , Thesis , Masters , MSocSci
- Identifier: http://hdl.handle.net/10962/148540 , vital:38748
- Description: Despite historical precedents, poverty among white people in South Africa remains an anomaly and a paradox. Likewise, the perceptions of work and employment among poor (under- and unemployed) whites in contemporary South Africa have received scant attention in the scholarly literature. Using the conceptual frameworks of critical whiteness studies and segmented labour market theory – as a way of combining subjective and objective considerations – this research seeks to describe and explain the perceptions and experiences of the labour market among poor whites living in a homeless shelter in Johannesburg. Eight respondents were chosen for extended, in-depth interviews in an effort to develop a fine-grained understanding of the pre-existing circumstances that affected their access to information and thus shaped their choices in the labour market, as well as to ascertain what they believed to be the barriers that they face in the labour market. The findings varied, with most of the interviewees seeing ‘being white’ as the reason for their poverty and unemployment, while others exhibited some awareness of the role of their lack of skills and qualifications in their capacity to compete in higher segments of the labour market. The findings were also varied in the sense that not all interviewees experienced poverty in the same manner, with some having been part of the middle class prior to becoming poor, while others having been poor their entire lives. It was also found that class or socio-economic status seemed to have a greater impact than race on the labour market prospects of the interviewees. It is argued that the perceptions of these poor whites, which are informed by their lack of information about the workings of the labour market, rather than their lack of qualifications or their race, most affected their prospects in the labour market. The mechanisms they rely on when seeking employment reveal a poor knowledge of the local labour market and the ways in which they think their skillsets match up to the types of jobs they desire. The lack of understanding of the South African labour market and the policies that are in place to redress the legacies of apartheid are among the factors influencing the lack of success these poor whites are experiencing in their search for work.
- Full Text:
- Date Issued: 2020
Formulation development, manufacture and evaluation of a lamivudine-zidovudine nano co-crystal thermo-responsive suspension
- Authors: Witika, Bwalya Angel
- Date: 2020
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/140546 , vital:37897 , http://dx.doi.org/10.21504/10962/140546
- Description: Expected release date-April 2021
- Full Text:
- Date Issued: 2020
- Authors: Witika, Bwalya Angel
- Date: 2020
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/140546 , vital:37897 , http://dx.doi.org/10.21504/10962/140546
- Description: Expected release date-April 2021
- Full Text:
- Date Issued: 2020
A comparative study of the effect of different stabilizers on the critical quality attributes of self-assembling nano co-crystals
- Witika, Bwalya A, Smith, Vincent J, Walker, Roderick B
- Authors: Witika, Bwalya A , Smith, Vincent J , Walker, Roderick B
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183224 , vital:43931 , xlink:href=" https://doi.org/10.3390/pharmaceutics12020182"
- Description: Lamivudine (3TC) and zidovudine (AZT) are antiviral agents used orally to manage HIV/AIDS infection. A pseudo one-solvent bottom-up approach was used to develop and produce nano co-crystals of 3TC and AZT. Equimolar amounts of 3TC dissolved in de-ionized water and AZT in methanol were rapidly injected into a pre-cooled vessel and sonicated at 4 °C. The resultant suspensions were characterized using a Zetasizer. The particle size, polydispersity index and Zeta potential were elucidated. Further characterization was undertaken using powder X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, and energy dispersive X-ray spectroscopy scanning electron microscopy. Different surfactants were assessed for their ability to stabilize the nano co-crystals and for their ability to produce nano co-crystals with specific and desirable critical quality attributes (CQA) including particle size (PS) less than 1000 nm, polydispersity index (PDI) less than 0.500 and Zeta potential (ZP) less than −30 mV. All surfactants produced co-crystals in the nanometer range. The PDI and PS are concentration-dependent for all nano co-crystals manufactured while only ZP was within specification when sodium dodecyl sulfate was used in the process.
- Full Text:
- Date Issued: 2020
- Authors: Witika, Bwalya A , Smith, Vincent J , Walker, Roderick B
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183224 , vital:43931 , xlink:href=" https://doi.org/10.3390/pharmaceutics12020182"
- Description: Lamivudine (3TC) and zidovudine (AZT) are antiviral agents used orally to manage HIV/AIDS infection. A pseudo one-solvent bottom-up approach was used to develop and produce nano co-crystals of 3TC and AZT. Equimolar amounts of 3TC dissolved in de-ionized water and AZT in methanol were rapidly injected into a pre-cooled vessel and sonicated at 4 °C. The resultant suspensions were characterized using a Zetasizer. The particle size, polydispersity index and Zeta potential were elucidated. Further characterization was undertaken using powder X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, and energy dispersive X-ray spectroscopy scanning electron microscopy. Different surfactants were assessed for their ability to stabilize the nano co-crystals and for their ability to produce nano co-crystals with specific and desirable critical quality attributes (CQA) including particle size (PS) less than 1000 nm, polydispersity index (PDI) less than 0.500 and Zeta potential (ZP) less than −30 mV. All surfactants produced co-crystals in the nanometer range. The PDI and PS are concentration-dependent for all nano co-crystals manufactured while only ZP was within specification when sodium dodecyl sulfate was used in the process.
- Full Text:
- Date Issued: 2020
Biocompatibility of biomaterials for nanoencapsulation: Current approaches
- Witika, Bwalya A, Makoni, Pedzisai A, Matafwali, Scott K, Chabalenge, Billy, Mwila, Chiluba, Kalungia, Aubrey C, Nkanga, Christian I, Bapolisi, Alain M, Walker, Roderick B
- Authors: Witika, Bwalya A , Makoni, Pedzisai A , Matafwali, Scott K , Chabalenge, Billy , Mwila, Chiluba , Kalungia, Aubrey C , Nkanga, Christian I , Bapolisi, Alain M , Walker, Roderick B
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183289 , vital:43939 , xlink:href="https://doi.org/10.3390/nano10091649"
- Description: Nanoencapsulation is an approach to circumvent shortcomings such as reduced bioavailability, undesirable side effects, frequent dosing and unpleasant organoleptic properties of conventional drug delivery systems. The process of nanoencapsulation involves the use of biomaterials such as surfactants and/or polymers, often in combination with charge inducers and/or ligands for targeting. The biomaterials selected for nanoencapsulation processes must be as biocompatible as possible. The type(s) of biomaterials used for different nanoencapsulation approaches are highlighted and their use and applicability with regard to haemo- and, histocompatibility, cytotoxicity, genotoxicity and carcinogenesis are discussed.
- Full Text:
- Date Issued: 2020
- Authors: Witika, Bwalya A , Makoni, Pedzisai A , Matafwali, Scott K , Chabalenge, Billy , Mwila, Chiluba , Kalungia, Aubrey C , Nkanga, Christian I , Bapolisi, Alain M , Walker, Roderick B
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183289 , vital:43939 , xlink:href="https://doi.org/10.3390/nano10091649"
- Description: Nanoencapsulation is an approach to circumvent shortcomings such as reduced bioavailability, undesirable side effects, frequent dosing and unpleasant organoleptic properties of conventional drug delivery systems. The process of nanoencapsulation involves the use of biomaterials such as surfactants and/or polymers, often in combination with charge inducers and/or ligands for targeting. The biomaterials selected for nanoencapsulation processes must be as biocompatible as possible. The type(s) of biomaterials used for different nanoencapsulation approaches are highlighted and their use and applicability with regard to haemo- and, histocompatibility, cytotoxicity, genotoxicity and carcinogenesis are discussed.
- Full Text:
- Date Issued: 2020
Quality by Design Optimization of Cold Sonochemical Synthesis of Zidovudine-Lamivudine Nanosuspensions:
- Witika, Bwalya A, Smith, Vincent J, Walker, Roderick B
- Authors: Witika, Bwalya A , Smith, Vincent J , Walker, Roderick B
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148424 , vital:38738 , https://doi.org/10.3390/pharmaceutics12040367
- Description: Lamivudine (3TC) and zidovudine (AZT) are antiviral agents used to manage HIV/AIDS infection. The compounds require frequent dosing, exhibit unpredictable bioavailability and a side effect profile that includes hepato- and haema-toxicity. A novel pseudo one-solvent bottom-up approach and Design of Experiments using sodium dodecyl sulphate (SDS) and α-tocopheryl polyethylene glycol succinate 1000 (TPGS 1000) to electrosterically stablize the nano co-crystals was used to develop, produce and optimize 3TC and AZT nano co-crystals. Equimolar solutions of 3TC in surfactant dissolved in de-ionised water and AZT in methanol were rapidly injected into a vessel and sonicated at 4 °C.
- Full Text:
- Date Issued: 2020
- Authors: Witika, Bwalya A , Smith, Vincent J , Walker, Roderick B
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148424 , vital:38738 , https://doi.org/10.3390/pharmaceutics12040367
- Description: Lamivudine (3TC) and zidovudine (AZT) are antiviral agents used to manage HIV/AIDS infection. The compounds require frequent dosing, exhibit unpredictable bioavailability and a side effect profile that includes hepato- and haema-toxicity. A novel pseudo one-solvent bottom-up approach and Design of Experiments using sodium dodecyl sulphate (SDS) and α-tocopheryl polyethylene glycol succinate 1000 (TPGS 1000) to electrosterically stablize the nano co-crystals was used to develop, produce and optimize 3TC and AZT nano co-crystals. Equimolar solutions of 3TC in surfactant dissolved in de-ionised water and AZT in methanol were rapidly injected into a vessel and sonicated at 4 °C.
- Full Text:
- Date Issued: 2020