Petits récits: creative perspectives of Chinese encounters in Zambia
- Authors: Mwaba, Stary
- Date: 2020
- Subjects: Personal narratives , Lyotard, Jean-François, 1924-1998 , Art and society -- Zambia , Social practice (Art) -- Zambia , Art and globalization -- Zambia , China -- Relations -- Zambia , Storytelling in art , Colonization in art
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: http://hdl.handle.net/10962/146355 , vital:38518
- Description: This mini-thesis, which supports my MFA exhibition Black Mountain, articulates on-the- ground creative perspectives of the Zambia-China discourse, through the representation of little narratives - les petits récits - connected to personal experiences. Through my creative production as an artist, I respond to perceptions of the Chinese presence in Africa. I utilize historical and contemporary personal narratives to complicate existing perceptions of Chinese presence in my home context of Zambia. “Petit récits”, or “little narratives”, in Francois Lyotard’s term, refers to personal stories of individuals that subvert dominant master-narratives and their legitimization in social-cultural structure. In the case of China’s presence in Zambia, I refer to the dichotomized narratives in the media as metanarratives which pay little attention to the people on the ground and propose the approach of “little narratives” to foreground the lived experiences of Zambians who have individual encounters with Chinese in various social spaces. By employing the narratives of my family members through installations, paintings, and drawings, I intervene in a broader China-Africa discourse that is often driven by economics and politics, and I attach importance to the little narratives. In my thesis I divide my material into three chapters; each chapter grows out of an encounter with the presence of China (and Chinese people) in Zambia in relation to the very personal narratives of family members - Zoë my daughter, my grandma, and Ngolo my cousin. The first chapter focuses on my work Chinese Cabbage as my entry point to this topic, which is based on a school experiment I did with my daughter Zoë. In this chapter I also discuss the current discourses around China’s presence. Chapter two revisits the Zambian-Chinese historical encounters in memory of my grandma’s insaka stories about the construction of TAZARA Railway, and thus my works discussed in this chapter attach importance to the individual engagements from a historical perspective. Chapter three discusses in particular the controversial issues around Black Mountain and the works inspired by my cousin Ngolo’s stories of mining in Black Mountain and dealing with the Chinese traders.
- Full Text:
- Date Issued: 2020
- Authors: Mwaba, Stary
- Date: 2020
- Subjects: Personal narratives , Lyotard, Jean-François, 1924-1998 , Art and society -- Zambia , Social practice (Art) -- Zambia , Art and globalization -- Zambia , China -- Relations -- Zambia , Storytelling in art , Colonization in art
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: http://hdl.handle.net/10962/146355 , vital:38518
- Description: This mini-thesis, which supports my MFA exhibition Black Mountain, articulates on-the- ground creative perspectives of the Zambia-China discourse, through the representation of little narratives - les petits récits - connected to personal experiences. Through my creative production as an artist, I respond to perceptions of the Chinese presence in Africa. I utilize historical and contemporary personal narratives to complicate existing perceptions of Chinese presence in my home context of Zambia. “Petit récits”, or “little narratives”, in Francois Lyotard’s term, refers to personal stories of individuals that subvert dominant master-narratives and their legitimization in social-cultural structure. In the case of China’s presence in Zambia, I refer to the dichotomized narratives in the media as metanarratives which pay little attention to the people on the ground and propose the approach of “little narratives” to foreground the lived experiences of Zambians who have individual encounters with Chinese in various social spaces. By employing the narratives of my family members through installations, paintings, and drawings, I intervene in a broader China-Africa discourse that is often driven by economics and politics, and I attach importance to the little narratives. In my thesis I divide my material into three chapters; each chapter grows out of an encounter with the presence of China (and Chinese people) in Zambia in relation to the very personal narratives of family members - Zoë my daughter, my grandma, and Ngolo my cousin. The first chapter focuses on my work Chinese Cabbage as my entry point to this topic, which is based on a school experiment I did with my daughter Zoë. In this chapter I also discuss the current discourses around China’s presence. Chapter two revisits the Zambian-Chinese historical encounters in memory of my grandma’s insaka stories about the construction of TAZARA Railway, and thus my works discussed in this chapter attach importance to the individual engagements from a historical perspective. Chapter three discusses in particular the controversial issues around Black Mountain and the works inspired by my cousin Ngolo’s stories of mining in Black Mountain and dealing with the Chinese traders.
- 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
Chinese Cabbage:
- Authors: Mwaba, Stary
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146699 , vital:38549 , https://www.ru.ac.za/artsofafrica/latestnews/rhodesparticipatesintheafrica-chinasymposiumatthegoetheinstitute.html
- Description: Stary Mwaba, an MFA candidate in the Arts of Africa and the Global South research team in the Fine Art Department, presented a paper on his installation, Chinese Cabbage, which was first displayed in his solo exhibition, Life on Mars, at the Künstlerhaus Bethanien in Germany in 2015. At the Africa–China symposium, Mwaba talked about his personal inroad into the Zambia–China debate, which draws from a family history of living along the Tazara Railway that was built by the Chinese in the 1960s, as well as the experience of his daughter attending a Chinese-run international school in Lusaka. Mwaba is currently expanding this research as part of his MFA studies at Rhodes by collecting oral narratives along the line of rail in Zambia and by addressing, through his painting practice, issues pertinent to the controversial copper slug known as Black Mountain in Kitwe.
- Full Text:
- Date Issued: 2017
- Authors: Mwaba, Stary
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146699 , vital:38549 , https://www.ru.ac.za/artsofafrica/latestnews/rhodesparticipatesintheafrica-chinasymposiumatthegoetheinstitute.html
- Description: Stary Mwaba, an MFA candidate in the Arts of Africa and the Global South research team in the Fine Art Department, presented a paper on his installation, Chinese Cabbage, which was first displayed in his solo exhibition, Life on Mars, at the Künstlerhaus Bethanien in Germany in 2015. At the Africa–China symposium, Mwaba talked about his personal inroad into the Zambia–China debate, which draws from a family history of living along the Tazara Railway that was built by the Chinese in the 1960s, as well as the experience of his daughter attending a Chinese-run international school in Lusaka. Mwaba is currently expanding this research as part of his MFA studies at Rhodes by collecting oral narratives along the line of rail in Zambia and by addressing, through his painting practice, issues pertinent to the controversial copper slug known as Black Mountain in Kitwe.
- Full Text:
- Date Issued: 2017
Narratives and home: remembering an almost forgotten walk
- Bezuidenhout, Natasha Belinda
- Authors: Bezuidenhout, Natasha Belinda
- Date: 2019
- Subjects: Home in literature , Home in art , Artists -- South Africa
- Language: English
- Type: text , Thesis , Masters , MFA
- Identifier: http://hdl.handle.net/10962/115039 , vital:34072
- Description: The title of my exhibition Bittersoet alludes to the self-exploratory nature of my practice, as I interrogate the personal memories associated with objects that characterise the relationship between myself and my mother (mamma). This supporting document, Narratives and Home: Remembering an almost forgotten walk, considers the key conceptual concerns informing my practice. In this mini-thesis, I address the question: ‘What is a home?’. Drawing from my own Fine Art Practice, I explore how home can be examined as a product of the imagination, rather than only as a physical place. I consider how ‘home’ is constructed as the primary objective within an ideological framework defined by history, memory and narrative. Engaging beyond the idea of ‘home’ as a fixed structure or place, I examine the idea of ‘home’ as something fluid that is negotiated and defined by the interaction between objects and language. It is concerned with dialectics of memory and narrative as they pertain directly to an experience of both searching for and reimagining home through metaphorical representations. In particular, I explore how home can be seen as equally familiar and unfamiliar, existing in-between, always changing, never fixed, rather in a constant state of flux. The concept of home is addressed in a dialogical process by using Afrikaans as my mother tongue, I narrate informal conversations between myself and my mother. These conversations transform and expand into hybrid words, memories and narratives to form a layered continuous dialogue between my practice and research. This notion relates to exploring oneself and the ‘fictions’ of the past. The self being fundamental to the individual comprehension of both ‘place’ and ‘space’.
- Full Text:
- Date Issued: 2019
- Authors: Bezuidenhout, Natasha Belinda
- Date: 2019
- Subjects: Home in literature , Home in art , Artists -- South Africa
- Language: English
- Type: text , Thesis , Masters , MFA
- Identifier: http://hdl.handle.net/10962/115039 , vital:34072
- Description: The title of my exhibition Bittersoet alludes to the self-exploratory nature of my practice, as I interrogate the personal memories associated with objects that characterise the relationship between myself and my mother (mamma). This supporting document, Narratives and Home: Remembering an almost forgotten walk, considers the key conceptual concerns informing my practice. In this mini-thesis, I address the question: ‘What is a home?’. Drawing from my own Fine Art Practice, I explore how home can be examined as a product of the imagination, rather than only as a physical place. I consider how ‘home’ is constructed as the primary objective within an ideological framework defined by history, memory and narrative. Engaging beyond the idea of ‘home’ as a fixed structure or place, I examine the idea of ‘home’ as something fluid that is negotiated and defined by the interaction between objects and language. It is concerned with dialectics of memory and narrative as they pertain directly to an experience of both searching for and reimagining home through metaphorical representations. In particular, I explore how home can be seen as equally familiar and unfamiliar, existing in-between, always changing, never fixed, rather in a constant state of flux. The concept of home is addressed in a dialogical process by using Afrikaans as my mother tongue, I narrate informal conversations between myself and my mother. These conversations transform and expand into hybrid words, memories and narratives to form a layered continuous dialogue between my practice and research. This notion relates to exploring oneself and the ‘fictions’ of the past. The self being fundamental to the individual comprehension of both ‘place’ and ‘space’.
- Full Text:
- Date Issued: 2019
A musical exile
- Authors: Thomas, Cornelius
- Date: 2001-05-18
- Subjects: Butler, Jonathan Jazz musicians -- South Africa Guitarists -- South Africa Concerts -- South Africa
- Type: article
- Identifier: http://hdl.handle.net/10962/50102 , vital:25959 , This image is held at the Cory Library for Humanities Research at Rhodes University. For further information contact cory@ru.ac.za. The digitisation of this image was made possible through a generous grant received from the Andrew W. Mellon Foundation 2014-2017. , MS 20 048
- Description: Photocopied article from the newspaper The Daily Dispatch about Jonathan Butler
- Full Text:
- Date Issued: 2001-05-18
- Authors: Thomas, Cornelius
- Date: 2001-05-18
- Subjects: Butler, Jonathan Jazz musicians -- South Africa Guitarists -- South Africa Concerts -- South Africa
- Type: article
- Identifier: http://hdl.handle.net/10962/50102 , vital:25959 , This image is held at the Cory Library for Humanities Research at Rhodes University. For further information contact cory@ru.ac.za. The digitisation of this image was made possible through a generous grant received from the Andrew W. Mellon Foundation 2014-2017. , MS 20 048
- Description: Photocopied article from the newspaper The Daily Dispatch about Jonathan Butler
- Full Text:
- Date Issued: 2001-05-18
Contemporary Zambian art, conceptualism and the ‘global’ art world
- Authors: Mulenga, Andrew Mukuka
- Date: 2017
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: http://hdl.handle.net/10962/5187 , vital:20784
- Description: In Zambia, ‘contemporary art’ (as a category constructed by the European-dominated international art world), was introduced by the European settler community and continued within its preserve, remaining largely inaccessible to the indigenous community of Africans until Zambia’s independence in 1964. This thesis traces the integration of Africans into the contemporary art community and attributes the process, in part, to a small group of artists of European descent who played a significant role in engaging with Zambians, working side by side with them, subsequently influencing their art production and implicitly shaping the ways in which ‘Zambian’ art ‘ought to’ look for decades to come. The research traces the early days of contemporary art practice in Zambia to the Lusaka Art Society and Art Centre Foundation that was founded and run by an all-settler group of formally trained artists with a particular inclination towards sculpture and painting. In the wake of the integration however, art production in the formalist manner was further proliferated by the European diplomatic community which would also go as far as dictating artistic subject matter. This thesis argues that the Eurocentric and pre-eminently formalist approach to contemporary art has cost Zambian artists an international presence. I submit that the few instances where contemporary Zambian art practice has penetrated the ‘global art’ scene or caught the attention of international curators is due to artists adopting more radical conceptual approaches to art production, often creating tensions with local viewers. This thesis also examines conceptualism in contemporary Zambian art practice and examines the inequalities of the ‘global art’ world. I argue that conceptual art, although not generally accepted on the Zambian art scene, has played a vital role in helping Zambian artists enter the global art world, albeit modestly.
- Full Text:
- Date Issued: 2017
- Authors: Mulenga, Andrew Mukuka
- Date: 2017
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: http://hdl.handle.net/10962/5187 , vital:20784
- Description: In Zambia, ‘contemporary art’ (as a category constructed by the European-dominated international art world), was introduced by the European settler community and continued within its preserve, remaining largely inaccessible to the indigenous community of Africans until Zambia’s independence in 1964. This thesis traces the integration of Africans into the contemporary art community and attributes the process, in part, to a small group of artists of European descent who played a significant role in engaging with Zambians, working side by side with them, subsequently influencing their art production and implicitly shaping the ways in which ‘Zambian’ art ‘ought to’ look for decades to come. The research traces the early days of contemporary art practice in Zambia to the Lusaka Art Society and Art Centre Foundation that was founded and run by an all-settler group of formally trained artists with a particular inclination towards sculpture and painting. In the wake of the integration however, art production in the formalist manner was further proliferated by the European diplomatic community which would also go as far as dictating artistic subject matter. This thesis argues that the Eurocentric and pre-eminently formalist approach to contemporary art has cost Zambian artists an international presence. I submit that the few instances where contemporary Zambian art practice has penetrated the ‘global art’ scene or caught the attention of international curators is due to artists adopting more radical conceptual approaches to art production, often creating tensions with local viewers. This thesis also examines conceptualism in contemporary Zambian art practice and examines the inequalities of the ‘global art’ world. I argue that conceptual art, although not generally accepted on the Zambian art scene, has played a vital role in helping Zambian artists enter the global art world, albeit modestly.
- Full Text:
- Date Issued: 2017
Kuntanshi yamikalile (The Future): speculative nonconformity in the works of Zambian visual artists
- Authors: Mulenga,Andrew Mukuka
- Date: 2021
- Subjects: Future in art , Africa -- In art , Art, Zambian , Art, African , Artists -- Zambia , Nyandoro, Gareth
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/172203 , vital:42175 , 10.21504/10962/172203
- Description: In recent years, select African visual artists practising on the continent as well as in its diaspora have increasingly been attracted to themes that explore, portray or grapple with Africa’s future. Along with this increasing popularity of the ‘future’ or indeed ‘African futuristic’ themes by visual artists, such themes have also attracted academic consideration among various scholars, resulting primarily in topics described as ‘African Futurism’ or Afrofuturism. These are topics that may be used to disrupt what some scholars – across disciplines and in various contexts – have highlighted as the persistent presumptive notions that portray Africa as a hinterland (Hassan 1999; Sefa Dei, Hall and Goldin Rosenberg 2000; Simbao 2007; Soyinka-Airewele and Edozie 2010; Moyo 2013; Keita, L. 2014; Green 2014; Serpell 2016). This study makes an effort to critique certain aspects of ‘African Art History’ with regard to the representation of Africa, and raises the following question: How can an analysis of artistic portrayals of ‘the future’ portrayed in the works of select contemporary Zambian artists be used to critique the positioning of Africa as ‘backward’, an occurrence at the intersection of a dualistic framing of tradition versus modern. Furthermore, how can this be used to break down this dichotomy in order to challenge lingering perceptions of African belatedness? The study analyses ways in which this belatedness is challenged by the juxtaposition of traditional, contemporary and futuristic elements by discussing a series of topics and debates associated to African cultures and technology that may be deemed disconnected from the contemporary lived experiences of Africans based on the continent. The study acknowledges that there is no singular ‘African Art History’ that one can talk of and there have been various shifts in how it has been perceived. I argue that while currently the African art history that is written in the West does not simplistically position Africa as backward as it may have done in the past, there appear to be moments of a hangover of this perception (Lamp 1999:4). What started out as a largely Western scholarly discourse of African art history occurred in about the 1950s and the journal African Arts started in the 1960s. Even before contemporary African art became a big thing in the 1990s for the largely US- and Europe-based discourses there were many discussions in the US about how the ‘old’ art history tended to freeze time and that this was not appropriate (Drewal 1991 et al). In order to advance the discourse on contemporary African visual arts I present critical analyses of the select works of Zambian artists to develop interpretations of the broader uses of the aforementioned themes. The evidence that supports the core argument of this research is embedded in the images discussed throughout this dissertation. The artists featured in the study span several decades including artists who were active from the 1960s to the 1980s, such as Henry Tayali and Akwila Simpasa, as well as artists who have been practising since the 1980s, such as Chishimba Chansa and William Miko and those that are more current and have been producing work from the early 1990s and 2000s, such as Zenzele Chulu, Milumbe Haimbe, Stary Mwaba, Isaac Kalambata and Roy Jethro Phiri.
- Full Text:
- Date Issued: 2021
- Authors: Mulenga,Andrew Mukuka
- Date: 2021
- Subjects: Future in art , Africa -- In art , Art, Zambian , Art, African , Artists -- Zambia , Nyandoro, Gareth
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/172203 , vital:42175 , 10.21504/10962/172203
- Description: In recent years, select African visual artists practising on the continent as well as in its diaspora have increasingly been attracted to themes that explore, portray or grapple with Africa’s future. Along with this increasing popularity of the ‘future’ or indeed ‘African futuristic’ themes by visual artists, such themes have also attracted academic consideration among various scholars, resulting primarily in topics described as ‘African Futurism’ or Afrofuturism. These are topics that may be used to disrupt what some scholars – across disciplines and in various contexts – have highlighted as the persistent presumptive notions that portray Africa as a hinterland (Hassan 1999; Sefa Dei, Hall and Goldin Rosenberg 2000; Simbao 2007; Soyinka-Airewele and Edozie 2010; Moyo 2013; Keita, L. 2014; Green 2014; Serpell 2016). This study makes an effort to critique certain aspects of ‘African Art History’ with regard to the representation of Africa, and raises the following question: How can an analysis of artistic portrayals of ‘the future’ portrayed in the works of select contemporary Zambian artists be used to critique the positioning of Africa as ‘backward’, an occurrence at the intersection of a dualistic framing of tradition versus modern. Furthermore, how can this be used to break down this dichotomy in order to challenge lingering perceptions of African belatedness? The study analyses ways in which this belatedness is challenged by the juxtaposition of traditional, contemporary and futuristic elements by discussing a series of topics and debates associated to African cultures and technology that may be deemed disconnected from the contemporary lived experiences of Africans based on the continent. The study acknowledges that there is no singular ‘African Art History’ that one can talk of and there have been various shifts in how it has been perceived. I argue that while currently the African art history that is written in the West does not simplistically position Africa as backward as it may have done in the past, there appear to be moments of a hangover of this perception (Lamp 1999:4). What started out as a largely Western scholarly discourse of African art history occurred in about the 1950s and the journal African Arts started in the 1960s. Even before contemporary African art became a big thing in the 1990s for the largely US- and Europe-based discourses there were many discussions in the US about how the ‘old’ art history tended to freeze time and that this was not appropriate (Drewal 1991 et al). In order to advance the discourse on contemporary African visual arts I present critical analyses of the select works of Zambian artists to develop interpretations of the broader uses of the aforementioned themes. The evidence that supports the core argument of this research is embedded in the images discussed throughout this dissertation. The artists featured in the study span several decades including artists who were active from the 1960s to the 1980s, such as Henry Tayali and Akwila Simpasa, as well as artists who have been practising since the 1980s, such as Chishimba Chansa and William Miko and those that are more current and have been producing work from the early 1990s and 2000s, such as Zenzele Chulu, Milumbe Haimbe, Stary Mwaba, Isaac Kalambata and Roy Jethro Phiri.
- Full Text:
- Date Issued: 2021
Mulling over Art with Andrew Mulenga: UNZA, Hone students mitigate Zambia-China relations
- Authors: Mulenga, Andrew
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146837 , vital:38562 , https://www.themastonline.com/2019/10/01/mulling-overt-art-unza-hone-students-mitigate-zambia-china-relations/
- Description: China’s presence in Africa has been a contentious issue coupled with speculation that the Asian economic powerhouse is taking over the continent through some kind of neo-colonialism instigated by what some are calling the “Chinese Debt Trap”.
- Full Text:
- Date Issued: 2019
- Authors: Mulenga, Andrew
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146837 , vital:38562 , https://www.themastonline.com/2019/10/01/mulling-overt-art-unza-hone-students-mitigate-zambia-china-relations/
- Description: China’s presence in Africa has been a contentious issue coupled with speculation that the Asian economic powerhouse is taking over the continent through some kind of neo-colonialism instigated by what some are calling the “Chinese Debt Trap”.
- Full Text:
- Date Issued: 2019
Omics-based molecular techniques in oral pathology centred cancer: prospect and challenges in Africa
- Adeola, Henry A., Soyele, Olujide.O., Adefuye, Anthonio O., Jimoh, Sikiru A., Butali, Azeez
- Authors: Adeola, Henry A. , Soyele, Olujide.O. , Adefuye, Anthonio O. , Jimoh, Sikiru A. , Butali, Azeez
- Date: 2017
- Subjects: Eastern Cape, South Africa Oral mucosa--Cancer Oral Pathology Cancer Computer File
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/5857 , vital:44658 , https://DOI10.1186/s12935-017-0432-8
- Description: Background:The completion of the human genome project and the accomplished milestones in the human proteome project; as well as the progress made so far in computational bioinformatics and “big data” processing have contributed immensely to individualized/personalized medicine in the developed world.Main body:At the dawn of precision medicine, various omics-based therapies and bioengineering can now be applied accurately for the diagnosis, prognosis, treatment, and risk stratification of cancer in a manner that was hitherto not thought possible. The widespread introduction of genomics and other omics-based approaches into the postgraduate training curriculum of diverse medical and dental specialties, including pathology has improved the proficiency of practitioners in the use of novel molecular signatures in patient management. In addition, intricate details about disease disparity among different human populations are beginning to emerge. This would facilitate the use of tailor-made novel theranostic methods based on emerging molecular evidences.Conclusion:In this review, we examined the challenges and prospects of using currently available omics-based technologies vis-à-vis oral pathology as well as prompt cancer diagnosis and treatment in a resource limited setting.Keywords:Omics-based, Molecular, Developing world, Oral pathology, Challenges
- Full Text:
- Date Issued: 2017
Omics-based molecular techniques in oral pathology centred cancer: prospect and challenges in Africa
- Authors: Adeola, Henry A. , Soyele, Olujide.O. , Adefuye, Anthonio O. , Jimoh, Sikiru A. , Butali, Azeez
- Date: 2017
- Subjects: Eastern Cape, South Africa Oral mucosa--Cancer Oral Pathology Cancer Computer File
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/5857 , vital:44658 , https://DOI10.1186/s12935-017-0432-8
- Description: Background:The completion of the human genome project and the accomplished milestones in the human proteome project; as well as the progress made so far in computational bioinformatics and “big data” processing have contributed immensely to individualized/personalized medicine in the developed world.Main body:At the dawn of precision medicine, various omics-based therapies and bioengineering can now be applied accurately for the diagnosis, prognosis, treatment, and risk stratification of cancer in a manner that was hitherto not thought possible. The widespread introduction of genomics and other omics-based approaches into the postgraduate training curriculum of diverse medical and dental specialties, including pathology has improved the proficiency of practitioners in the use of novel molecular signatures in patient management. In addition, intricate details about disease disparity among different human populations are beginning to emerge. This would facilitate the use of tailor-made novel theranostic methods based on emerging molecular evidences.Conclusion:In this review, we examined the challenges and prospects of using currently available omics-based technologies vis-à-vis oral pathology as well as prompt cancer diagnosis and treatment in a resource limited setting.Keywords:Omics-based, Molecular, Developing world, Oral pathology, Challenges
- Full Text:
- Date Issued: 2017
Chirema Chine Mazano Chinotamba Chakazendama Madziro
- Authors: Mapondera, Wallen
- Date: 2020
- Subjects: Art, Zimbabwean , Art -- Economic aspects -- Zimbabwe , Artists -- Zimbabwe , Takadiwa, Moffet , Nyandoro, Gareth , Clottey, Serge Attiku , Mapondera, Wallen -- Exhibitions
- Language: English
- Type: text , Thesis , Masters , MFA
- Identifier: http://hdl.handle.net/10962/147457 , vital:38638
- Description: This mini-thesis has developed as a practice-based supporting document to the exhibition Chirema Chine Mazano Chinotamba Chakazendama Madziro. The exhibition responds to how people become innovative in finding alternative means of survival and staying relevant in an economically depressed country. Zimbabwe is often the first country that comes to mind when people talk about hyperinflation; the situation was and still is intolerable, but somehow its citizens find means to pull through. Unemployment and poverty are the main causes of physical and mental problems for an individual. With this thesis, I highlight the innovations employed by Zimbabweans as a way of keeping themselves busy. I approach this through analysing the Zimbabwean general public’s creative reactions, and by tracing Zimbabwean visual artists’ use of found objects as a reaction to the country’s economic hardships. As people have been pushed to find alternative ways of survival, Zimbabwean artists in particular also shifted from using conventional art materials due to their unavailability. They began to redefine what art material is by employing objects in their artworks that previously had a non-art function. As such, there is a growing need to recognise, classify and document the shifts and establish platforms to generate growth of these innovations. In this minithesis I discuss my own practice, and I analyse the works of Moffat Takadiwa, Gareth Nyandoro and Serge Attiku Clottey.
- Full Text:
- Date Issued: 2020
- Authors: Mapondera, Wallen
- Date: 2020
- Subjects: Art, Zimbabwean , Art -- Economic aspects -- Zimbabwe , Artists -- Zimbabwe , Takadiwa, Moffet , Nyandoro, Gareth , Clottey, Serge Attiku , Mapondera, Wallen -- Exhibitions
- Language: English
- Type: text , Thesis , Masters , MFA
- Identifier: http://hdl.handle.net/10962/147457 , vital:38638
- Description: This mini-thesis has developed as a practice-based supporting document to the exhibition Chirema Chine Mazano Chinotamba Chakazendama Madziro. The exhibition responds to how people become innovative in finding alternative means of survival and staying relevant in an economically depressed country. Zimbabwe is often the first country that comes to mind when people talk about hyperinflation; the situation was and still is intolerable, but somehow its citizens find means to pull through. Unemployment and poverty are the main causes of physical and mental problems for an individual. With this thesis, I highlight the innovations employed by Zimbabweans as a way of keeping themselves busy. I approach this through analysing the Zimbabwean general public’s creative reactions, and by tracing Zimbabwean visual artists’ use of found objects as a reaction to the country’s economic hardships. As people have been pushed to find alternative ways of survival, Zimbabwean artists in particular also shifted from using conventional art materials due to their unavailability. They began to redefine what art material is by employing objects in their artworks that previously had a non-art function. As such, there is a growing need to recognise, classify and document the shifts and establish platforms to generate growth of these innovations. In this minithesis I discuss my own practice, and I analyse the works of Moffat Takadiwa, Gareth Nyandoro and Serge Attiku Clottey.
- Full Text:
- Date Issued: 2020
Freshwater invertebrate fauna of the Tristan da Cunha islands (South Atlantic Ocean), with new records for Inaccessible and Nightingale Islands
- Authors: Barber-James, Helen M
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:7001 , http://hdl.handle.net/10962/d1008360
- Description: As part of a multidisciplinary floristic-faunistic study, a three week survey of the invertebrate fauna of Inaccessible Island (South Atlantic Ocean) was carried out in October / November 1989. In addition, one day of collecting was done on Nightingale Island. This paper deals only with the fauna associated with freshwater ecosystems from these islands, some of which are usually associated with marine or brackish conditions. On Inaccessible Island, five distinct types of freshwater body were identified - pH neutral streams, acidic streams (pH 5), an open pool of standing water (pH 6), areas of acidic bog, and seepages down rock faces. The survey, the most comprehensive for Inaccessible Island to date, has resulted in the discovery of 19 aquatic invertebrate species previously unrecorded on Inaccessible Island, two new to Nightingale Island, and 14 of which are new to the Tristan da Cunha archipelago. Many of the species are known from other parts of the world, indicating a low degree of endemicity within the freshwater invertebrate community. Recolonisation from the source populations, preventing an isolated gene pool, may account for the low endemicity. Several of the species have a degree of salinity tolerance, enabling them to withstand transportation across tracts of ocean, and others have marine origins.
- Full Text:
- Date Issued: 2007
- Authors: Barber-James, Helen M
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:7001 , http://hdl.handle.net/10962/d1008360
- Description: As part of a multidisciplinary floristic-faunistic study, a three week survey of the invertebrate fauna of Inaccessible Island (South Atlantic Ocean) was carried out in October / November 1989. In addition, one day of collecting was done on Nightingale Island. This paper deals only with the fauna associated with freshwater ecosystems from these islands, some of which are usually associated with marine or brackish conditions. On Inaccessible Island, five distinct types of freshwater body were identified - pH neutral streams, acidic streams (pH 5), an open pool of standing water (pH 6), areas of acidic bog, and seepages down rock faces. The survey, the most comprehensive for Inaccessible Island to date, has resulted in the discovery of 19 aquatic invertebrate species previously unrecorded on Inaccessible Island, two new to Nightingale Island, and 14 of which are new to the Tristan da Cunha archipelago. Many of the species are known from other parts of the world, indicating a low degree of endemicity within the freshwater invertebrate community. Recolonisation from the source populations, preventing an isolated gene pool, may account for the low endemicity. Several of the species have a degree of salinity tolerance, enabling them to withstand transportation across tracts of ocean, and others have marine origins.
- Full Text:
- Date Issued: 2007
Freshwater invertebrate fauna of the Tristan da Cunha islands (South Atlantic Ocean), with new records for Inaccessible and Nightingale Islands
- Barber-James, Helen Margaret
- Authors: Barber-James, Helen Margaret
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6940 , http://hdl.handle.net/10962/d1011964
- Description: As part of a multidisciplinary floristic-faunistic study, a three week survey of the invertebrate fauna of Inaccessible Island (South Atlantic Ocean) was carried out in October / November 1989. In addition, one day of collecting was done on Nightingale Island. This paper deals only with the fauna associated with freshwater ecosystems from these islands, some of which are usually associated with marine or brackish conditions. On Inaccessible Island, five distinct types of freshwater body were identified - pH neutral streams, acidic streams (pH 5), an open pool of standing water (pH 6), areas of acidic bog, and seepages down rock faces. The survey, the most comprehensive for Inaccessible Island to date, has resulted in the discovery of 19 aquatic invertebrate species previously unrecorded on Inaccessible Island, two new to Nightingale Island, and 14 of which are new to the Tristan da Cunha archipelago. Many of the species are known from other parts of the world, indicating a low degree of endemicity within the freshwater invertebrate community. Recolonisation from the source populations, preventing an isolated gene pool, may account for the low endemicity. Several of the species have a degree of salinity tolerance, enabling them to withstand transportation across tracts of ocean, and others have marine origins.
- Full Text:
- Date Issued: 2007
- Authors: Barber-James, Helen Margaret
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6940 , http://hdl.handle.net/10962/d1011964
- Description: As part of a multidisciplinary floristic-faunistic study, a three week survey of the invertebrate fauna of Inaccessible Island (South Atlantic Ocean) was carried out in October / November 1989. In addition, one day of collecting was done on Nightingale Island. This paper deals only with the fauna associated with freshwater ecosystems from these islands, some of which are usually associated with marine or brackish conditions. On Inaccessible Island, five distinct types of freshwater body were identified - pH neutral streams, acidic streams (pH 5), an open pool of standing water (pH 6), areas of acidic bog, and seepages down rock faces. The survey, the most comprehensive for Inaccessible Island to date, has resulted in the discovery of 19 aquatic invertebrate species previously unrecorded on Inaccessible Island, two new to Nightingale Island, and 14 of which are new to the Tristan da Cunha archipelago. Many of the species are known from other parts of the world, indicating a low degree of endemicity within the freshwater invertebrate community. Recolonisation from the source populations, preventing an isolated gene pool, may account for the low endemicity. Several of the species have a degree of salinity tolerance, enabling them to withstand transportation across tracts of ocean, and others have marine origins.
- Full Text:
- Date Issued: 2007
Bacterial degradation of waste coal
- Authors: Madikiza, Lwazikazi
- Date: 2014
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/54576 , vital:26590
- Description: As an energy source coal has one of the largest agglomerations in the world. Consequently mining of coal creates large volumes of waste in the form of low ranks coals. The complex structure of coal makes it difficult for the microorganisms to degrade and relatively few bacteria and fungi have been shown to break down coal. This study aimed to investigate bacteria not previously known to degrade coal. In this study bacteria were isolated from hydrocarbon contaminated sites and inoculated in coal medium where coal served as the only carbon source. Three strains produced a yellow – brown supernatant after 14 d of incubation at 30 °C. Bacteria generating a yellow – brown coloured supernatant were presumed to possess coal degrading capabilities and the best performing of these bacterial species was identified using 16s rDNA as Bacillus flexus. Scanning electron microscopy showed that there was a close association between the bacterium and substrate coal. The close association of bacteria to substrate suggested that these organisms were able to maximize solubilisation. FT-IR spectroscopic analysis demonstrated the addition of single bonded compounds COOH, OH, CN and CH that were absent prior to bacterial interaction. The increase in oxygen rich regions indicated degradation of the coal substrate. Elemental analysis showed that there was a decrease in carbon content from 47 % to 24 % during the 14 day incubation period. Reduction in coal carbon content was assumed to be due to bacterial utilization for metabolism and growth particularly as untreated coal substrate showed minimal loss of carbon. Analysis of the residual culture medium revealed that there was a linear increase in humic-like substance concentration for 8 d, coincident with increased coal biosolubilisation and colour change. Laccase activity was insignificant, and at 13 d enzyme activity was only 5×10-3 U/L suggesting that B. flexus may use a different mechanism to degrade coal. Residual culture medium remaining after bacterial action on the coal substrate appeared to possess plant growth promoting activity. This soluble biodegradation product with characteristics similar to humic acid-like substances was shown to impact growth of radish cotyledons. Expansion of isolated radish cotyledons was enhanced by 140% when incubated in coal biodegradation product. In conclusion, this study has yielded B. flexus and two other unidentified bacteria, isolated from polyaromatic hydrocarbon contaminated soils, and demonstrated the ability of these microorganisms to degrade waste coal. Further studies to elucidate the mechanism of coal breakdown by B. flexus, synergies with other coal degrading microorganisms, and incorporation of bacterium into Fungcoal bioprocess technology is imminent.
- Full Text:
- Date Issued: 2014
- Authors: Madikiza, Lwazikazi
- Date: 2014
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/54576 , vital:26590
- Description: As an energy source coal has one of the largest agglomerations in the world. Consequently mining of coal creates large volumes of waste in the form of low ranks coals. The complex structure of coal makes it difficult for the microorganisms to degrade and relatively few bacteria and fungi have been shown to break down coal. This study aimed to investigate bacteria not previously known to degrade coal. In this study bacteria were isolated from hydrocarbon contaminated sites and inoculated in coal medium where coal served as the only carbon source. Three strains produced a yellow – brown supernatant after 14 d of incubation at 30 °C. Bacteria generating a yellow – brown coloured supernatant were presumed to possess coal degrading capabilities and the best performing of these bacterial species was identified using 16s rDNA as Bacillus flexus. Scanning electron microscopy showed that there was a close association between the bacterium and substrate coal. The close association of bacteria to substrate suggested that these organisms were able to maximize solubilisation. FT-IR spectroscopic analysis demonstrated the addition of single bonded compounds COOH, OH, CN and CH that were absent prior to bacterial interaction. The increase in oxygen rich regions indicated degradation of the coal substrate. Elemental analysis showed that there was a decrease in carbon content from 47 % to 24 % during the 14 day incubation period. Reduction in coal carbon content was assumed to be due to bacterial utilization for metabolism and growth particularly as untreated coal substrate showed minimal loss of carbon. Analysis of the residual culture medium revealed that there was a linear increase in humic-like substance concentration for 8 d, coincident with increased coal biosolubilisation and colour change. Laccase activity was insignificant, and at 13 d enzyme activity was only 5×10-3 U/L suggesting that B. flexus may use a different mechanism to degrade coal. Residual culture medium remaining after bacterial action on the coal substrate appeared to possess plant growth promoting activity. This soluble biodegradation product with characteristics similar to humic acid-like substances was shown to impact growth of radish cotyledons. Expansion of isolated radish cotyledons was enhanced by 140% when incubated in coal biodegradation product. In conclusion, this study has yielded B. flexus and two other unidentified bacteria, isolated from polyaromatic hydrocarbon contaminated soils, and demonstrated the ability of these microorganisms to degrade waste coal. Further studies to elucidate the mechanism of coal breakdown by B. flexus, synergies with other coal degrading microorganisms, and incorporation of bacterium into Fungcoal bioprocess technology is imminent.
- Full Text:
- Date Issued: 2014
Differential regulation of wheat (Triticum aestivum) callose synthases during Russian wheat aphid (diuraphis noxia)infestation
- Authors: Ngwenya, Nompilo
- Date: 2017
- Subjects: Russian wheat aphid Wheat -- Diseases and pests
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8100 , vital:31522
- Description: Plant production serves as the primary food source for all living beings and is continuously being affected by many biotic and abiotic factors. Wheat, one of the most consumed cereal crops in the world and the second most cultivated crop after maize in South Africa, is continuously being affected by Russian wheat aphid (RWA) since 1978. To counteract the effect of this aphid, the first resistant wheat cultivar was developed in 1984 in South Africa containing the Dn1 resistance gene. However, the mechanism of action of the resistance is still not fully understood to date. The feeding of the RWA on the wheat induces callose deposition especially in susceptible wheat cultivars, linking the β-1.3-polysaccharide (callose) to the resistance mechanism. Callose is synthesized by callose synthases, also known as glucan synthase-like genes (GSL). Not much is known about the mechanism of action of callose synthases or how they are regulated in response to the RWA. Bioinformatics tools, such as those available at NCBI, were used to identify the wheat callose synthases genes. The proteins encoded by the identified wheat callose synthases genes, were then analyzed for conserved domain motifs using the MEME suite and InterproScan, sequence similarities using ClustaL Omega and transmembrane domains using HMMTOP and ProtCamp. These were then compared with those of the already characterized Arabidopsis callose synthase proteins in an attempt to identify the wheat callose synthase(s) that responds to aphid feeding. Further bioinformatics studies were carried out to identify the presence of biotic stress associated cis-acting regulatory elements found in the 1.5 kbp upstream region of the start codon of the Arabidopsis callose synthase genes. Eight partial wheat callose synthase sequences were identified and two of these (TaGSL2 and TaGSL22) showed high similarities to the AtGSL5, which is up-regulated in response to aphid feeding in Arabidopsis. Six of the wheat callose synthase genes were mediated to code for the functional callose synthases proteins: TaGSL3, 8, 12, 19, 22 and 23, and analyzed for conserved protein motifs. Based on the sequence similarities and conserved protein domains, TaGSL2 and TaGSL22 were found to be the most similar to AtGSL5 and most likely to respond to RWA infestation. Cis-acting regulatory element analyses confirmed the possibility of TaGSL22 being responsible for callose deposition in wheat as biotic stress associated cis-acting regulatory elements, Box W1, TC- rich element and W- box were all found in the 1.5 kbp upstream of the TaGSL22 coding region. Callose was quantified in both susceptible and resistant wheat cultivars using the aniline blue fluorescence method. When infested with RWA-SA1, the susceptible wheat cultivar (Tugela) deposited significantly higher amounts of callose, compared to the resistant wheat cultivar (Tugela DN), which deposited little, to no callose with respect to the control samples. Transcription analysis, of the TaGSL2 and TaGSL22 in RWA-SA2 infested Tugela and Tugela DN wheat cultivars, was performed using real time polymerase chain reaction (qPCR). Both TaGSL2 and TaGSL22 genes were up-regulated in Tugela and Tugela DN wheat cultivars in response to RWA-SA2 infestation, with TaGSL22 being more expressed than TaGSL2 in both cultivars, indicating that RWA-SA2 is able to overcome the resistance of Tugela DN and cause callose deposition. However, significantly higher expression of both genes was still observed in the susceptible, Tugela wheat cultivar. This study therefore confirms that callose deposition is associated with RWA-SA1 feeding, only in the susceptible wheat cultivar, Tugela and not the resistant cultivar, Tugela DN. However, during RWA-SA2 feeding, two of the eight identified callose synthases in wheat, are up-regulated in response to RWA-SA2 feeding, in both the resistant and susceptible wheat cultivars with higher levels observed in the susceptible wheat cultivar when compared to the resistant wheat cultivar. TaGSL2 and TaGSL22 are therefore implicated in the callose deposition observed in the susceptible and resistant wheat cultivars, after RWA-SA2 infestation. Further studies are required to confirm the differential regulation of the two wheat callose synthases proteins during RWA infestation and their possible role in the resistance mechanism of the resistant wheat cultivar, Tugela DN.
- Full Text:
- Date Issued: 2017
- Authors: Ngwenya, Nompilo
- Date: 2017
- Subjects: Russian wheat aphid Wheat -- Diseases and pests
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8100 , vital:31522
- Description: Plant production serves as the primary food source for all living beings and is continuously being affected by many biotic and abiotic factors. Wheat, one of the most consumed cereal crops in the world and the second most cultivated crop after maize in South Africa, is continuously being affected by Russian wheat aphid (RWA) since 1978. To counteract the effect of this aphid, the first resistant wheat cultivar was developed in 1984 in South Africa containing the Dn1 resistance gene. However, the mechanism of action of the resistance is still not fully understood to date. The feeding of the RWA on the wheat induces callose deposition especially in susceptible wheat cultivars, linking the β-1.3-polysaccharide (callose) to the resistance mechanism. Callose is synthesized by callose synthases, also known as glucan synthase-like genes (GSL). Not much is known about the mechanism of action of callose synthases or how they are regulated in response to the RWA. Bioinformatics tools, such as those available at NCBI, were used to identify the wheat callose synthases genes. The proteins encoded by the identified wheat callose synthases genes, were then analyzed for conserved domain motifs using the MEME suite and InterproScan, sequence similarities using ClustaL Omega and transmembrane domains using HMMTOP and ProtCamp. These were then compared with those of the already characterized Arabidopsis callose synthase proteins in an attempt to identify the wheat callose synthase(s) that responds to aphid feeding. Further bioinformatics studies were carried out to identify the presence of biotic stress associated cis-acting regulatory elements found in the 1.5 kbp upstream region of the start codon of the Arabidopsis callose synthase genes. Eight partial wheat callose synthase sequences were identified and two of these (TaGSL2 and TaGSL22) showed high similarities to the AtGSL5, which is up-regulated in response to aphid feeding in Arabidopsis. Six of the wheat callose synthase genes were mediated to code for the functional callose synthases proteins: TaGSL3, 8, 12, 19, 22 and 23, and analyzed for conserved protein motifs. Based on the sequence similarities and conserved protein domains, TaGSL2 and TaGSL22 were found to be the most similar to AtGSL5 and most likely to respond to RWA infestation. Cis-acting regulatory element analyses confirmed the possibility of TaGSL22 being responsible for callose deposition in wheat as biotic stress associated cis-acting regulatory elements, Box W1, TC- rich element and W- box were all found in the 1.5 kbp upstream of the TaGSL22 coding region. Callose was quantified in both susceptible and resistant wheat cultivars using the aniline blue fluorescence method. When infested with RWA-SA1, the susceptible wheat cultivar (Tugela) deposited significantly higher amounts of callose, compared to the resistant wheat cultivar (Tugela DN), which deposited little, to no callose with respect to the control samples. Transcription analysis, of the TaGSL2 and TaGSL22 in RWA-SA2 infested Tugela and Tugela DN wheat cultivars, was performed using real time polymerase chain reaction (qPCR). Both TaGSL2 and TaGSL22 genes were up-regulated in Tugela and Tugela DN wheat cultivars in response to RWA-SA2 infestation, with TaGSL22 being more expressed than TaGSL2 in both cultivars, indicating that RWA-SA2 is able to overcome the resistance of Tugela DN and cause callose deposition. However, significantly higher expression of both genes was still observed in the susceptible, Tugela wheat cultivar. This study therefore confirms that callose deposition is associated with RWA-SA1 feeding, only in the susceptible wheat cultivar, Tugela and not the resistant cultivar, Tugela DN. However, during RWA-SA2 feeding, two of the eight identified callose synthases in wheat, are up-regulated in response to RWA-SA2 feeding, in both the resistant and susceptible wheat cultivars with higher levels observed in the susceptible wheat cultivar when compared to the resistant wheat cultivar. TaGSL2 and TaGSL22 are therefore implicated in the callose deposition observed in the susceptible and resistant wheat cultivars, after RWA-SA2 infestation. Further studies are required to confirm the differential regulation of the two wheat callose synthases proteins during RWA infestation and their possible role in the resistance mechanism of the resistant wheat cultivar, Tugela DN.
- Full Text:
- Date Issued: 2017
Sex ratios of Coccophagus atratus compere (Hymenoptera:Aphelinidae) in relation to host availability
- Authors: Donaldson, John Sydney
- Date: 1985
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5632 , http://hdl.handle.net/10962/d1004933
- Description: The mode of sex determination in most Hymenoptera is that of arrhenotokous parthenogenesis, i.e. females originate from fertilised eggs and males develop parthenogenetically from unfertilised ones. Females can therefore determine the sex of each of their offspring by controlling fertilisation. This has led to much speculation about the factors that govern hymenopteran sex ratios. Many sex ratio theories predict that solitary Hymenoptera should produce male and female offspring in a ratio of 1:1. The limited data available on sex ratios in solitary Hymenoptera does not support this prediction. However, for various reasons, data may not be representative and few detailed studies have been done. The purpose of this study was, therefore, to examine sex ratios of Coccophagus atratus, a solitary hymenopteran parasitoid, to determine whether sex ratios in this species approach 1: 1. C. atratus is a suitable species for sex ratio studies because male and female eggs are deposited in different hosts. The sex of deposited eggs can, therefore, be determined at oviposition. This eliminates any possible effects of differential mortality. Laboratory experiments were designed to determine whether C. atratus females deposit male and female eggs in fixed proportions or in a set sequence. In addition, samples of hosts were collected from the field to assess C. atratus sex ratios under natural conditions. Results show that C. atratus females do not produce sex ratios that approach 1:1 and male and female eggs are not deposited in a set sequence. Sex ratios are variable and appear to be related to the relative abundance of hosts suitable for female development and for male development. These results are discussed in relation to current sex ratio theories.
- Full Text:
- Date Issued: 1985
Sex ratios of Coccophagus atratus compere (Hymenoptera:Aphelinidae) in relation to host availability
- Authors: Donaldson, John Sydney
- Date: 1985
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5632 , http://hdl.handle.net/10962/d1004933
- Description: The mode of sex determination in most Hymenoptera is that of arrhenotokous parthenogenesis, i.e. females originate from fertilised eggs and males develop parthenogenetically from unfertilised ones. Females can therefore determine the sex of each of their offspring by controlling fertilisation. This has led to much speculation about the factors that govern hymenopteran sex ratios. Many sex ratio theories predict that solitary Hymenoptera should produce male and female offspring in a ratio of 1:1. The limited data available on sex ratios in solitary Hymenoptera does not support this prediction. However, for various reasons, data may not be representative and few detailed studies have been done. The purpose of this study was, therefore, to examine sex ratios of Coccophagus atratus, a solitary hymenopteran parasitoid, to determine whether sex ratios in this species approach 1: 1. C. atratus is a suitable species for sex ratio studies because male and female eggs are deposited in different hosts. The sex of deposited eggs can, therefore, be determined at oviposition. This eliminates any possible effects of differential mortality. Laboratory experiments were designed to determine whether C. atratus females deposit male and female eggs in fixed proportions or in a set sequence. In addition, samples of hosts were collected from the field to assess C. atratus sex ratios under natural conditions. Results show that C. atratus females do not produce sex ratios that approach 1:1 and male and female eggs are not deposited in a set sequence. Sex ratios are variable and appear to be related to the relative abundance of hosts suitable for female development and for male development. These results are discussed in relation to current sex ratio theories.
- Full Text:
- Date Issued: 1985
Work in Progress Issue no.29 - Caught in the crossfire
- WIP
- Authors: WIP
- Date: July 1983
- Subjects: WIP
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/111411 , vital:33449
- Description: During July 1983? the Ciskei Transport Corporation (CTC) announced that it intended increasing bus fares on certain routes. A committee representing commuters objected to the proposed increases, arguing that commuters could not afford them, given the recent price rise in the cost of basic foodstuffs. The CTC - partly owned by the Ciskei government - dismissed these objections, and the committee duly called a boycott of all buses owned by the company. On 19 July the boycott began. The following day the press reported an 80% drop in the use of CTC buses. From this point on, police, the army, and a private army of vigilantes were used by the Ciskei administration to force commuters to use buses. In the past two months, Ciskeian authorities have indicated their willingness to use any official and unofficial, legal and extra-legal forms of violence to break the boycott. Violence has escalated, and the conflict has now become a test of strength between bantustan rulers and their unwilling subjects. The first concerted attempt to break the boycott was directed at private car owners and taxi drivers. Police established road blocks on routes in and out of Mdantsane. From then on, vigilantes under the control of police harassed car passengers, car drivers and taxi drivers. Police manhandled car passengers, using sjamboks on some occasions. Cars have been confiscated, and passengers forced to alight and return to bus stops. The brunt of the tactics used to break the bus boycott have been borne by train commuters. As with vehicle commuters, the means used to prevent them from catching trains appear to know no bounds. Civilians have been attacked, assaulted and fired on by police and vigilante groups under police control. Residents of Mdantsane put the death toll at over 60. By September, at least 67 people - most of them trade unionists - had been detained under Ciskei security legislation. In addition, over 1 000 commuters have been detained for technical offences such as curfew breaking. In September, the South African Allied Workers' Union was banned by the Sebe administration. On 4 August, the Ciskei's minister of justice declared a state of emergency. No person may be on the streets without permission between 22h00 and 04h00. No more than four people may congregate together in houses or on the streets. There have been numerous reports of assaults and torture of detainees held in the Ciskei, and a number of detainees have been admitted to hospital at various stages of their detention. As disturbing as are the number of people hospitalised are reports of the failure to hospitalise or treat other detainees injured in assaults. This is the context in which SARS, in conjunction with the Development Studies Group, is publishing a detailed report on the Ciskei. Produced by Nicholas Haysom, a research officer at the Centre for Applied Legal Studies, the report covers the political history of the Ciskei, security legislation, torture and repression in the past years, background to the current bus boycott, and methods used by the Ciskei administration to crush the boycott. There is also a section on the current schools boycott in the Ciskei, the involvement of South African security police and firms in the Ciskei crisis, and the response of people resident in the area. Subscribers to SARS publications will receive this report as part of their subscription. Copies will also be available at bookshops stocking Work In Progress, or directly from SARS
- Full Text:
- Date Issued: July 1983
- Authors: WIP
- Date: July 1983
- Subjects: WIP
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/111411 , vital:33449
- Description: During July 1983? the Ciskei Transport Corporation (CTC) announced that it intended increasing bus fares on certain routes. A committee representing commuters objected to the proposed increases, arguing that commuters could not afford them, given the recent price rise in the cost of basic foodstuffs. The CTC - partly owned by the Ciskei government - dismissed these objections, and the committee duly called a boycott of all buses owned by the company. On 19 July the boycott began. The following day the press reported an 80% drop in the use of CTC buses. From this point on, police, the army, and a private army of vigilantes were used by the Ciskei administration to force commuters to use buses. In the past two months, Ciskeian authorities have indicated their willingness to use any official and unofficial, legal and extra-legal forms of violence to break the boycott. Violence has escalated, and the conflict has now become a test of strength between bantustan rulers and their unwilling subjects. The first concerted attempt to break the boycott was directed at private car owners and taxi drivers. Police established road blocks on routes in and out of Mdantsane. From then on, vigilantes under the control of police harassed car passengers, car drivers and taxi drivers. Police manhandled car passengers, using sjamboks on some occasions. Cars have been confiscated, and passengers forced to alight and return to bus stops. The brunt of the tactics used to break the bus boycott have been borne by train commuters. As with vehicle commuters, the means used to prevent them from catching trains appear to know no bounds. Civilians have been attacked, assaulted and fired on by police and vigilante groups under police control. Residents of Mdantsane put the death toll at over 60. By September, at least 67 people - most of them trade unionists - had been detained under Ciskei security legislation. In addition, over 1 000 commuters have been detained for technical offences such as curfew breaking. In September, the South African Allied Workers' Union was banned by the Sebe administration. On 4 August, the Ciskei's minister of justice declared a state of emergency. No person may be on the streets without permission between 22h00 and 04h00. No more than four people may congregate together in houses or on the streets. There have been numerous reports of assaults and torture of detainees held in the Ciskei, and a number of detainees have been admitted to hospital at various stages of their detention. As disturbing as are the number of people hospitalised are reports of the failure to hospitalise or treat other detainees injured in assaults. This is the context in which SARS, in conjunction with the Development Studies Group, is publishing a detailed report on the Ciskei. Produced by Nicholas Haysom, a research officer at the Centre for Applied Legal Studies, the report covers the political history of the Ciskei, security legislation, torture and repression in the past years, background to the current bus boycott, and methods used by the Ciskei administration to crush the boycott. There is also a section on the current schools boycott in the Ciskei, the involvement of South African security police and firms in the Ciskei crisis, and the response of people resident in the area. Subscribers to SARS publications will receive this report as part of their subscription. Copies will also be available at bookshops stocking Work In Progress, or directly from SARS
- Full Text:
- Date Issued: July 1983
The Kinshasa-based Kin ArtStudio in the Democratic Republic of Congo: visual arts spaces and the potential to challenge global art's representative and legitimizing mechanisms
- Tshilumba Mukendi, Jean-Sylvain
- Authors: Tshilumba Mukendi, Jean-Sylvain
- Date: 2019
- Subjects: Space (Art) , Art -- Congo (Democratic Republic) , Art and globalization , Postcolonialism and the arts -- Congo (Democratic Republic) , Arts, Modern -- 21st century , Arts publicity , Arts, Modern -- 21st century -- Economic aspects , Arts, Modern -- 21st century -- Social aspects , Bondo, Vitshois Mwilambwe , Kin ArtStudio , Beauté Congo – 1926-2015 – Congo Kitoko
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/115050 , vital:34073
- Description: The emergence of visual art spaces over the past few decades on the African continent invites art practitioners, historians and critics to re-examine the conditions of production, diffusion and reception of contemporary art of Africa. In this thesis I critically engage with these conditions in relation to artworks and practices of the Democratic Republic of Congo, considering the curatorial logic that has governed the ‘global art world’. I focus on the Kin ArtStudio as my main case study. I undertook research within this art space in 2016, from the 10th of April to the 15th of June, and again from the 16th of July to the 12th of September. My position as a participant observer turned out to be as engaging as informative. The Kin ArtStudio is a Kinshasa-based visual art platform founded in 2011 by the Congolese artist Vitshois Mwilambwe Bondo. It was established out of the will to empower emerging artists in that specific context, and facilitate the negotiation that the legitimization of their creations entails in today’s global art and cultural dynamics. In order to evaluate the stakes of such negotiation, I start with reviewing the existing mechanisms, trends and networks that have legitimized visual art productions of the Democratic Republic of Congo on a global stage, as exemplified by the Beauté Congo – Congo Kitoko exhibition (2015). Then, my enquiry evolves towards specificity, towards the immediacy and the subjectivity that characterize Kinshasa's urban and socio-cultural context, and visual art practices therein. Subjectivity also applies to my four months immersive experience with that art space. Drawing from my observations, setbacks, hopes and recent academic and practical debates around contemporary art practices on the African continent, the role those art spaces can play in the curatorship, circulation, reception and commodification of contemporary art productions cannot be underestimated. While operating in lasting postcolonial settings, they are going through the negotiation of their global and translocal situatedness, which can in turn lead to new legitimizing narratives. These will more appropriately inform understandings of contemporary art practices of Africa, challenging the identifying prism sustained by the ‘global art world’.
- Full Text:
- Date Issued: 2019
- Authors: Tshilumba Mukendi, Jean-Sylvain
- Date: 2019
- Subjects: Space (Art) , Art -- Congo (Democratic Republic) , Art and globalization , Postcolonialism and the arts -- Congo (Democratic Republic) , Arts, Modern -- 21st century , Arts publicity , Arts, Modern -- 21st century -- Economic aspects , Arts, Modern -- 21st century -- Social aspects , Bondo, Vitshois Mwilambwe , Kin ArtStudio , Beauté Congo – 1926-2015 – Congo Kitoko
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/115050 , vital:34073
- Description: The emergence of visual art spaces over the past few decades on the African continent invites art practitioners, historians and critics to re-examine the conditions of production, diffusion and reception of contemporary art of Africa. In this thesis I critically engage with these conditions in relation to artworks and practices of the Democratic Republic of Congo, considering the curatorial logic that has governed the ‘global art world’. I focus on the Kin ArtStudio as my main case study. I undertook research within this art space in 2016, from the 10th of April to the 15th of June, and again from the 16th of July to the 12th of September. My position as a participant observer turned out to be as engaging as informative. The Kin ArtStudio is a Kinshasa-based visual art platform founded in 2011 by the Congolese artist Vitshois Mwilambwe Bondo. It was established out of the will to empower emerging artists in that specific context, and facilitate the negotiation that the legitimization of their creations entails in today’s global art and cultural dynamics. In order to evaluate the stakes of such negotiation, I start with reviewing the existing mechanisms, trends and networks that have legitimized visual art productions of the Democratic Republic of Congo on a global stage, as exemplified by the Beauté Congo – Congo Kitoko exhibition (2015). Then, my enquiry evolves towards specificity, towards the immediacy and the subjectivity that characterize Kinshasa's urban and socio-cultural context, and visual art practices therein. Subjectivity also applies to my four months immersive experience with that art space. Drawing from my observations, setbacks, hopes and recent academic and practical debates around contemporary art practices on the African continent, the role those art spaces can play in the curatorship, circulation, reception and commodification of contemporary art productions cannot be underestimated. While operating in lasting postcolonial settings, they are going through the negotiation of their global and translocal situatedness, which can in turn lead to new legitimizing narratives. These will more appropriately inform understandings of contemporary art practices of Africa, challenging the identifying prism sustained by the ‘global art world’.
- Full Text:
- Date Issued: 2019
Synthesis and characterization of group 12 dithiolate complexes as single source precursors for the preparation of hexadecylamine capped metal sulfide nanoparticles and polymer
- Authors: Osuntokun, Jejenija
- Date: 2016
- Subjects: Nanotechnology Nanoparticles Semiconductors
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/14060 , vital:39801
- Description: A series of heteroleptic mixed ligand complexes of some alkyl substituted thiourea, tetramethyl thiuram disulfide and 1-cyano-1-carboethoxy-2,2 ditholate of Zn(II) Cd(II) and Hg(II) have been synthesized by stoichiometry reactions of the ligands with respective metal salts. They have been characterized with analytical and spectroscopic techniques. Seven out of the 19 complexes synthesized are pyridine 2, 2 bipyridine and 1, 10 phenanthroline adducts of dissopropyl parent adducts of Zn(II) and Cd(II) complexes. All the complexes are proposed as four coordinate except the pyridine adducts, 2, 2’ bipyridine and 1, 10 phenanhroline adducts that are proposed as five and six coordinate respectively. All the complexes are solid, air stable and moisture stable for a many months. They are not soluble in common organic solvents but partially soluble in coordinating solvents like DMF and DMSO and due to their insolubility problems all attempts to grow single crystal of the complexes proved abortive. The complexes gave respective metal sulfide on thermal decomposition in TGA and this makes them to be potentially useful single source precursor for the synthesis of metal sulfide. All the complexes were invariably thermolysed in HDA to synthesis a series of HDA-capped ZnS, CdS and HgS nanoparticles. The optical properties of the nanoparticles reveal that they are all blue-shifted from the absorbance edge and this confirms quantum confinement of the nanoparticles. The transmittance electron microscope showed that the nanoparticles are in nanodimension. ZnS nanoparticles from the pyridine adducts gave HDA-capped ZnS nanoparticles with a mixture of hexagonal and cubic phases while the HDA capped CdS from the 2, 2 bipyridine and 1,10 phenanthroline gave anisotropic nanoparticles. The sizes of the CdS from the 1,10 phenanthroline adducts were also found to be biggest while CdS nanoparticles from 2,2 bipyridine adduct were also revealed to be bigger than the particle sizes obtained from the parent complex, (1-cyano-1 carboethoxyethylene-2,2-dithiolato- κ,S’S)-bis(N, N’-diisopropylthiourea -κS)cadmium(II). ZnS and CdS polymer encapsulated nanocomposites were also synthesized using a solution casting method. The polymers employed were; Polymethyl metharcrylate (PMMA), Poly(vinly alcohol) (PVA), and poly vinyl pyrrolidone (PVP). The structural and thermal properties of the pure polymers and the respective nanocomposites were investigated. It was observed that the ZnS/PVA and CdS/PVA were the most thermally stable composites when the thermal stability of the pure polymers were compared relative to the nanocomposites using data obtained from thermal decomposition results of the TGA.
- Full Text:
- Date Issued: 2016
- Authors: Osuntokun, Jejenija
- Date: 2016
- Subjects: Nanotechnology Nanoparticles Semiconductors
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/14060 , vital:39801
- Description: A series of heteroleptic mixed ligand complexes of some alkyl substituted thiourea, tetramethyl thiuram disulfide and 1-cyano-1-carboethoxy-2,2 ditholate of Zn(II) Cd(II) and Hg(II) have been synthesized by stoichiometry reactions of the ligands with respective metal salts. They have been characterized with analytical and spectroscopic techniques. Seven out of the 19 complexes synthesized are pyridine 2, 2 bipyridine and 1, 10 phenanthroline adducts of dissopropyl parent adducts of Zn(II) and Cd(II) complexes. All the complexes are proposed as four coordinate except the pyridine adducts, 2, 2’ bipyridine and 1, 10 phenanhroline adducts that are proposed as five and six coordinate respectively. All the complexes are solid, air stable and moisture stable for a many months. They are not soluble in common organic solvents but partially soluble in coordinating solvents like DMF and DMSO and due to their insolubility problems all attempts to grow single crystal of the complexes proved abortive. The complexes gave respective metal sulfide on thermal decomposition in TGA and this makes them to be potentially useful single source precursor for the synthesis of metal sulfide. All the complexes were invariably thermolysed in HDA to synthesis a series of HDA-capped ZnS, CdS and HgS nanoparticles. The optical properties of the nanoparticles reveal that they are all blue-shifted from the absorbance edge and this confirms quantum confinement of the nanoparticles. The transmittance electron microscope showed that the nanoparticles are in nanodimension. ZnS nanoparticles from the pyridine adducts gave HDA-capped ZnS nanoparticles with a mixture of hexagonal and cubic phases while the HDA capped CdS from the 2, 2 bipyridine and 1,10 phenanthroline gave anisotropic nanoparticles. The sizes of the CdS from the 1,10 phenanthroline adducts were also found to be biggest while CdS nanoparticles from 2,2 bipyridine adduct were also revealed to be bigger than the particle sizes obtained from the parent complex, (1-cyano-1 carboethoxyethylene-2,2-dithiolato- κ,S’S)-bis(N, N’-diisopropylthiourea -κS)cadmium(II). ZnS and CdS polymer encapsulated nanocomposites were also synthesized using a solution casting method. The polymers employed were; Polymethyl metharcrylate (PMMA), Poly(vinly alcohol) (PVA), and poly vinyl pyrrolidone (PVP). The structural and thermal properties of the pure polymers and the respective nanocomposites were investigated. It was observed that the ZnS/PVA and CdS/PVA were the most thermally stable composites when the thermal stability of the pure polymers were compared relative to the nanocomposites using data obtained from thermal decomposition results of the TGA.
- Full Text:
- Date Issued: 2016
Rhodeo, Vol. 22, No. 16
- Date: 1968-08-22
- Subjects: Grahamstown -- Newspapers , Journalism, Students -- South Africa , Rhodes University -- Activate , Rhodes University -- Students , Student newspapers and periodicals -- South Africa
- Language: English
- Type: Text
- Identifier: vital:14590 , http://hdl.handle.net/10962/d1019462
- Description: Rhodeo is the Independent Student Newspaper of Rhodes University. Located in Grahamstown, Rhodeo was established in 1947, and renamed in 1994 as Activate. During apartheid Rhodeo became an active part of the struggle for freedom of expression as part of the now defunct South African Student Press Union. Currently Activate is committed to informing Rhodes University students, staff and community members about relevant issues, mainly on campus. These issues range from hard news to more creative journalism. While Activate acts as a news source, one of its main objectives it to be accessible as a training ground for student journalists. The newspaper is run entirely by the students and is published twice a term. Activate is a free newspaper which receives an annual grant from the Rhodes University Student Representative Council, however, majority of its revenue is generated through advertising.
- Full Text:
- Date Issued: 1968-08-22
- Date: 1968-08-22
- Subjects: Grahamstown -- Newspapers , Journalism, Students -- South Africa , Rhodes University -- Activate , Rhodes University -- Students , Student newspapers and periodicals -- South Africa
- Language: English
- Type: Text
- Identifier: vital:14590 , http://hdl.handle.net/10962/d1019462
- Description: Rhodeo is the Independent Student Newspaper of Rhodes University. Located in Grahamstown, Rhodeo was established in 1947, and renamed in 1994 as Activate. During apartheid Rhodeo became an active part of the struggle for freedom of expression as part of the now defunct South African Student Press Union. Currently Activate is committed to informing Rhodes University students, staff and community members about relevant issues, mainly on campus. These issues range from hard news to more creative journalism. While Activate acts as a news source, one of its main objectives it to be accessible as a training ground for student journalists. The newspaper is run entirely by the students and is published twice a term. Activate is a free newspaper which receives an annual grant from the Rhodes University Student Representative Council, however, majority of its revenue is generated through advertising.
- Full Text:
- Date Issued: 1968-08-22
The adsorption of chelating reagents on oxide minerals
- Bryson, Michael Andrew Walker
- Authors: Bryson, Michael Andrew Walker
- Date: 1986
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:20969 , http://hdl.handle.net/10962/5729
- Description: This work constitutes a fundamental study of the interaction between chelating reagents and oxide minerals . The adsorption mechanisms have been elucidated for most of the systems generated by the oxides of copper(II) or iron(III) and chelating reagents octyl hydroxamate, N-phenylbenzohydroxamate, salicylaldoxime, 5-nitrosalicylaldoxime or 8-hydroxyquinoline. The results of the preliminary work on one of the systems, viz. the oxide-hydroxamate system, indicated that the classical type adsorption process, in which the reagent forms a uniform layer of chelate over the oxide surface was not applicable. Rather, the adsorption occurred via the formation of a discrete metal-chelate precipitate at the oxide surface. In order to better understand the associated with copper (II) oxide, adsorption process the oxide was recrystallized to produce a coarser material with a more uniform surface. This allowed the oxide surface to be viewed under the scanning electron microscope and also enabled the relative concentration of "surface" and "bulk" chelate to be assessed. A detailed investigation of the effect of the system variables; pH, conditioning period, concentration, temperature, surface area and dispersing reagent on the rate of precipitation of the copper chelate species of general form, Cu(chel)2' was made. In addition the chemical nature of the adsorbed species and the structural form of the precipitates were determined with the aid of infra-red spectroscopy and the scanning electron microscope. On the basis of these results a model has been formulated for the adsorption processes. In this model the adsorption dissolution, is considered to occur in stages: 1. Oxide dissolution, 2. metal complex formation, 3. Metal chelate precipitation at the oxide surface and 4. “bulk” chelate formation by post-precipitation processes. The precipitation process was examined in more detail by the study of the adsorption of chelate on copper metal. The results of this study showed that it was possible to relate the structural type of precipitate formed, ie. fibrous or platelike, to the degree of supersaturation of the metal complex in solution. Furthermore, it was found that the precipitate structure determined whether it remained attached to the surface or detached. Contact angle measurements of air bubbles on copper metal conditioned with chelate were related to the adsorption results in an attempt to isolate the optimum conditions for flotation of oxide minerals.
- Full Text:
- Date Issued: 1986
- Authors: Bryson, Michael Andrew Walker
- Date: 1986
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:20969 , http://hdl.handle.net/10962/5729
- Description: This work constitutes a fundamental study of the interaction between chelating reagents and oxide minerals . The adsorption mechanisms have been elucidated for most of the systems generated by the oxides of copper(II) or iron(III) and chelating reagents octyl hydroxamate, N-phenylbenzohydroxamate, salicylaldoxime, 5-nitrosalicylaldoxime or 8-hydroxyquinoline. The results of the preliminary work on one of the systems, viz. the oxide-hydroxamate system, indicated that the classical type adsorption process, in which the reagent forms a uniform layer of chelate over the oxide surface was not applicable. Rather, the adsorption occurred via the formation of a discrete metal-chelate precipitate at the oxide surface. In order to better understand the associated with copper (II) oxide, adsorption process the oxide was recrystallized to produce a coarser material with a more uniform surface. This allowed the oxide surface to be viewed under the scanning electron microscope and also enabled the relative concentration of "surface" and "bulk" chelate to be assessed. A detailed investigation of the effect of the system variables; pH, conditioning period, concentration, temperature, surface area and dispersing reagent on the rate of precipitation of the copper chelate species of general form, Cu(chel)2' was made. In addition the chemical nature of the adsorbed species and the structural form of the precipitates were determined with the aid of infra-red spectroscopy and the scanning electron microscope. On the basis of these results a model has been formulated for the adsorption processes. In this model the adsorption dissolution, is considered to occur in stages: 1. Oxide dissolution, 2. metal complex formation, 3. Metal chelate precipitation at the oxide surface and 4. “bulk” chelate formation by post-precipitation processes. The precipitation process was examined in more detail by the study of the adsorption of chelate on copper metal. The results of this study showed that it was possible to relate the structural type of precipitate formed, ie. fibrous or platelike, to the degree of supersaturation of the metal complex in solution. Furthermore, it was found that the precipitate structure determined whether it remained attached to the surface or detached. Contact angle measurements of air bubbles on copper metal conditioned with chelate were related to the adsorption results in an attempt to isolate the optimum conditions for flotation of oxide minerals.
- Full Text:
- Date Issued: 1986