A statistical study of the errors involved in the sampling and chemical analysis of soils and plants, with particular reference to citrus and pineapples
- Steyn, Willem Johannes Abraham
- Authors: Steyn, Willem Johannes Abraham
- Date: 1958
- Subjects: Soil chemistry , Plants -- Analysis , Soils -- Analysis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4506 , http://hdl.handle.net/10962/d1013291
- Description: 1. Accurate and reproducible methods for the determination of N and acid- extractable P in soils are described. The variations in N, P, and K found by intensive sampling of three different soil types are presented. 3. Suggestions for the adequate sampling of soils for various purposes arc given. 4. A study is presented of the preparative stages in leaf analysis (washing, drying, grinding and storage) as applied to citrus and pineapple leaf material. Likely errors are pointed out and procedures whereby these may be minimised are described. 5. A reliable wet-ashing procedure for obtaining leaf solutions is described. 6. Accurate and reproducible methods for the determination of total N, P,. K, Ca, Mg, Na, Fe, Mn, Zn and Cu in citrus and pineapple leaves are presented. 7. It is shown that diurnal variations in nutrient concentrations occur in citrus and pineapple leaves. 8. The variations in N, P, K, Ca, Mg, Na, Fe, Mn, Zn and Cu, occurring from tree to tree in 3 different Navel orange blocks are presented. It is shown that if all these elements are to be represented . to within 10% of the mean values on a 19 : 1 probability level, all the trees in the blocks would have to be sampled. Reasonable sampling procedures for various purposes are suggested. 9. The variations in N, P, K, Ca, Mg, Fe, Mn, Zn and Cu, occurring in 3 different Cayenne pineapple plantations are presented and described. Suitable sampling procedures are suggested.
- Full Text:
- Date Issued: 1958
- Authors: Steyn, Willem Johannes Abraham
- Date: 1958
- Subjects: Soil chemistry , Plants -- Analysis , Soils -- Analysis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4506 , http://hdl.handle.net/10962/d1013291
- Description: 1. Accurate and reproducible methods for the determination of N and acid- extractable P in soils are described. The variations in N, P, and K found by intensive sampling of three different soil types are presented. 3. Suggestions for the adequate sampling of soils for various purposes arc given. 4. A study is presented of the preparative stages in leaf analysis (washing, drying, grinding and storage) as applied to citrus and pineapple leaf material. Likely errors are pointed out and procedures whereby these may be minimised are described. 5. A reliable wet-ashing procedure for obtaining leaf solutions is described. 6. Accurate and reproducible methods for the determination of total N, P,. K, Ca, Mg, Na, Fe, Mn, Zn and Cu in citrus and pineapple leaves are presented. 7. It is shown that diurnal variations in nutrient concentrations occur in citrus and pineapple leaves. 8. The variations in N, P, K, Ca, Mg, Na, Fe, Mn, Zn and Cu, occurring from tree to tree in 3 different Navel orange blocks are presented. It is shown that if all these elements are to be represented . to within 10% of the mean values on a 19 : 1 probability level, all the trees in the blocks would have to be sampled. Reasonable sampling procedures for various purposes are suggested. 9. The variations in N, P, K, Ca, Mg, Fe, Mn, Zn and Cu, occurring in 3 different Cayenne pineapple plantations are presented and described. Suitable sampling procedures are suggested.
- Full Text:
- Date Issued: 1958
Heterologous expression of the helicoverpa armigera stunt virus in Saccharomyces cerevisiae
- Authors: Venter, Philip Arno
- Date: 2002
- Subjects: Helicoverpa armigera Saccharomyces cerevisiae
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3895 , http://hdl.handle.net/10962/d1003811
- Description: Lepidopteran insects like Helicoverpa armigera, more commonly known as the cotton bollworm, are economically important pests of a wide variety of crops throughout the world. The Helicoverpa armigera stunt virus (HaSV), a tetravirus with a bipartite single-stranded positive-sense RNA genome, has great potential as a biological pesticide against H. armigera. The larger genomic strand of this virus (RNA1) encodes the viral replicase, while the other (RNA2) encodes the 71 kDa capsid protein precursor (p71). 240 copies of p71 assemble into a procapsid with the concomitant encapsidation of the viral RNA. This is followed by a complex maturation event that is characterized by the autoproteolytic cleavage of p71 into the 64 kDa capsid protein (P64) and a 7 kDa peptide (p7). The rearrangements that occur during maturation results in the formation of mature HaSV capsids that can thereupon deliver RNA to other susceptible host cells. The principal objective of the research described in this study was to demonstrate that this virus could be assembled in Saccharomyces cerevisiae. S. cerevisiae expression vectors were constructed for the production of p71. This protein was detected in cell lysates from two different strains of S. cerevisiae, both containing either chromosomal or episomal copies of an expression cassette for P71. A number of factors relating to the expression of P71 (e.g. strains used, expression loci and expression rate) and the preparation of protein extracts from S. cerevisiae (e.g. the presence of various protease inhibitors and salt concentrations) were examined to attain optimal levels of soluble p71. A small fraction of the optimized soluble p71 was shown to be in the form of virus-like particles (VLPs), with a yield of ≤10⁷ VLPs from a 1.5l culture of P71⁺ cells. These particles were exclusively in the procapsid form, had a similar buoyant density to that of wild-type HaSV and could undergo maturation when the pH was reduced to 5. S. cerevisiae vectors were constructed for the episomal expression of the HaSV genomic RNAs. These vectors directed the transcription of RNA1 and RNA2 transcripts, which had similar sizes to those of the HaSV genomic RNAs. Mature HaSV particles were purified from cells, transgenic for P71, RNA1 and RNA2, by way of two different virus purification protocols that were developed during this study. RT-PCR analyses on RNA-extracts from these particles demonstrated that RNA transcripts, which were produced in trans with p71, could be encapsidated by HaSV capsids in S. cerevisiae. A droplet-feed bioassay on H. armigera larvae demonstrated that the S. cerevisiae-derived HaSV particles caused impaired larval development. This response was correlated with the detection of HaSV RNA2 in RNA extractions from larvae that were used in this bioassay. The results that were generated through the course of this study, provided proof for the concept of the non-host production of infectious HaSV particles from S. cerevisiae. This work could serve as a foundation for future research on the development of an expression system for the large-scale production of this virus as a biopesticide.
- Full Text:
- Date Issued: 2002
- Authors: Venter, Philip Arno
- Date: 2002
- Subjects: Helicoverpa armigera Saccharomyces cerevisiae
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3895 , http://hdl.handle.net/10962/d1003811
- Description: Lepidopteran insects like Helicoverpa armigera, more commonly known as the cotton bollworm, are economically important pests of a wide variety of crops throughout the world. The Helicoverpa armigera stunt virus (HaSV), a tetravirus with a bipartite single-stranded positive-sense RNA genome, has great potential as a biological pesticide against H. armigera. The larger genomic strand of this virus (RNA1) encodes the viral replicase, while the other (RNA2) encodes the 71 kDa capsid protein precursor (p71). 240 copies of p71 assemble into a procapsid with the concomitant encapsidation of the viral RNA. This is followed by a complex maturation event that is characterized by the autoproteolytic cleavage of p71 into the 64 kDa capsid protein (P64) and a 7 kDa peptide (p7). The rearrangements that occur during maturation results in the formation of mature HaSV capsids that can thereupon deliver RNA to other susceptible host cells. The principal objective of the research described in this study was to demonstrate that this virus could be assembled in Saccharomyces cerevisiae. S. cerevisiae expression vectors were constructed for the production of p71. This protein was detected in cell lysates from two different strains of S. cerevisiae, both containing either chromosomal or episomal copies of an expression cassette for P71. A number of factors relating to the expression of P71 (e.g. strains used, expression loci and expression rate) and the preparation of protein extracts from S. cerevisiae (e.g. the presence of various protease inhibitors and salt concentrations) were examined to attain optimal levels of soluble p71. A small fraction of the optimized soluble p71 was shown to be in the form of virus-like particles (VLPs), with a yield of ≤10⁷ VLPs from a 1.5l culture of P71⁺ cells. These particles were exclusively in the procapsid form, had a similar buoyant density to that of wild-type HaSV and could undergo maturation when the pH was reduced to 5. S. cerevisiae vectors were constructed for the episomal expression of the HaSV genomic RNAs. These vectors directed the transcription of RNA1 and RNA2 transcripts, which had similar sizes to those of the HaSV genomic RNAs. Mature HaSV particles were purified from cells, transgenic for P71, RNA1 and RNA2, by way of two different virus purification protocols that were developed during this study. RT-PCR analyses on RNA-extracts from these particles demonstrated that RNA transcripts, which were produced in trans with p71, could be encapsidated by HaSV capsids in S. cerevisiae. A droplet-feed bioassay on H. armigera larvae demonstrated that the S. cerevisiae-derived HaSV particles caused impaired larval development. This response was correlated with the detection of HaSV RNA2 in RNA extractions from larvae that were used in this bioassay. The results that were generated through the course of this study, provided proof for the concept of the non-host production of infectious HaSV particles from S. cerevisiae. This work could serve as a foundation for future research on the development of an expression system for the large-scale production of this virus as a biopesticide.
- Full Text:
- Date Issued: 2002
An Investigation into Social Factors Contributing to Intimate Partner Violence. A Case Study of Tentergate Village, Enoch Mgijima Municipality
- Authors: Ndubane, Masimbonge
- Date: 2019
- Subjects: Intimate partner violence
- Language: English
- Type: Thesis , Masters , MSoc (Anthropology)
- Identifier: http://hdl.handle.net/10353/16474 , vital:40723
- Description: This study sought to investigate social factors contributing to intimate partner violence in Tentergate village. Intimate partner violence or intimate personal violence, a matter once considered private, has gained increased attention as a public health crisis. In their efforts to better understand and prevent this behavior, social science researchers have discovered the link between gender inequality, early exposure to violence, spousal abuse and family conflicts. This paper uses social feminist, social learning and family violence theory to explain intimate partner violence. Participants‘ perceptions were assessed through systematic analysis. Quantitative and qualitative analysis was done on data obtained from interviews conducted on 30 women informants. The study revealed that there are several social factors contributing to intimate partner violence. In the final analysis, it argues that effective treatment and prevention should include both criminal justice and public health strategies.
- Full Text:
- Date Issued: 2019
- Authors: Ndubane, Masimbonge
- Date: 2019
- Subjects: Intimate partner violence
- Language: English
- Type: Thesis , Masters , MSoc (Anthropology)
- Identifier: http://hdl.handle.net/10353/16474 , vital:40723
- Description: This study sought to investigate social factors contributing to intimate partner violence in Tentergate village. Intimate partner violence or intimate personal violence, a matter once considered private, has gained increased attention as a public health crisis. In their efforts to better understand and prevent this behavior, social science researchers have discovered the link between gender inequality, early exposure to violence, spousal abuse and family conflicts. This paper uses social feminist, social learning and family violence theory to explain intimate partner violence. Participants‘ perceptions were assessed through systematic analysis. Quantitative and qualitative analysis was done on data obtained from interviews conducted on 30 women informants. The study revealed that there are several social factors contributing to intimate partner violence. In the final analysis, it argues that effective treatment and prevention should include both criminal justice and public health strategies.
- Full Text:
- Date Issued: 2019
Intimate masculinities in the work of Paul Emmanuel
- Authors: Bronner, Irene Enslé
- Date: 2011
- Subjects: Emmanuel, Paul, 1969- Masculinity in art Identity (Psychology) in art Gender identity in art Art, South African -- 21st century
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2397 , http://hdl.handle.net/10962/d1002193
- Description: Paul Emmanuel is a South African artist who produces incised drawings, outdoor installations and prints (particularly intaglio etchings and manière noire lithographs). These focus on the representation of male bodies and experience. Having begun his career as a collaborative printmaker, since 2002, his work has become more ambitious as well as critically acclaimed. In 2010, his most recent body of work, Transitions, was exhibited at the Smithsonian Museum of African Art in Washington D.C. I propose that Emmanuel represents the male body as a presence that either is not easily seen or that actively disappears or erases itself. Its subjectivity, and the viewer’s engagement with it, may be characterised as one of intimacy, exposure, loss and vulnerability. Emmanuel’s work may be said to question conventions and ideals of masculinity while, at the same time, refusing any prescriptive interpretation. To develop this proposition, I examine specifically Emmanuel’s incising drawing technique that ‘holds open’ transitions in male lives. In these liminal moments, Emmanuel represents men as ‘seen’ to change state or status, thereby exposing the ongoing process of building masculine identities. Equally elucidatory is Emmanuel’s imprinting of his own body, which, in his use of “traces” that reveal the vacillation between presence and absence, makes contingently ‘visible’ this gendering process, and has particular implications for the expression of subjectivity in a contemporary South African context.
- Full Text:
- Date Issued: 2011
- Authors: Bronner, Irene Enslé
- Date: 2011
- Subjects: Emmanuel, Paul, 1969- Masculinity in art Identity (Psychology) in art Gender identity in art Art, South African -- 21st century
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2397 , http://hdl.handle.net/10962/d1002193
- Description: Paul Emmanuel is a South African artist who produces incised drawings, outdoor installations and prints (particularly intaglio etchings and manière noire lithographs). These focus on the representation of male bodies and experience. Having begun his career as a collaborative printmaker, since 2002, his work has become more ambitious as well as critically acclaimed. In 2010, his most recent body of work, Transitions, was exhibited at the Smithsonian Museum of African Art in Washington D.C. I propose that Emmanuel represents the male body as a presence that either is not easily seen or that actively disappears or erases itself. Its subjectivity, and the viewer’s engagement with it, may be characterised as one of intimacy, exposure, loss and vulnerability. Emmanuel’s work may be said to question conventions and ideals of masculinity while, at the same time, refusing any prescriptive interpretation. To develop this proposition, I examine specifically Emmanuel’s incising drawing technique that ‘holds open’ transitions in male lives. In these liminal moments, Emmanuel represents men as ‘seen’ to change state or status, thereby exposing the ongoing process of building masculine identities. Equally elucidatory is Emmanuel’s imprinting of his own body, which, in his use of “traces” that reveal the vacillation between presence and absence, makes contingently ‘visible’ this gendering process, and has particular implications for the expression of subjectivity in a contemporary South African context.
- Full Text:
- Date Issued: 2011
Female school principals=perceptions of leadership in a male dominated education environment
- Authors: Mwingi, Mweru P
- Date: 2000
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/326 , vital:19948
- Description: Many well-known studies on leadership have ignored the perspective of women yet bear an emphasis on the importance of portraying leadership in its entirety. This would mean that all leadership perspectives are included and that leaders are allowed to speak for themselves and about themselves. It is this connection I have sought to establish how women perceive leadership by relating the experiences of four women in school principalship. I have used a factual questionnaire to establish the background of each one but, it is the in-depth interviews that yield the leadership perceptions. Borrowing from phenomenological procedures, the leadership experiences are related as Natural Meaning Units (NMUS) whereby all prior knowledge and possible bias are bracketed out. Reinforced by their journal entries, it is only the voice of the women that is heard. My study reinforces the observation of researchers and feminist scholars that women leaders are not only marginalised but also viewed from a perspective that is not their own. From the study, however, the one element about leadership that emerges as unique is the functioning of transformational leadership elements among women leaders in educational set-ups that are inherently traditional, bureaucratic and hierarchical. This is significant because there is an indication that women leaders are inclined to transformational leadership because it favours their feminine qualities. There is also evidence that school principals can embrace leadership diversity and finally, that leadership and the structures of leadership operation are not developed from without but from within the person of the leader and this is an incorporation of their vision and beliefs. In the context of South Africa, this study should be of potential significance because of the change that is taking place in the development and training of school principals.
- Full Text:
- Date Issued: 2000
- Authors: Mwingi, Mweru P
- Date: 2000
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/326 , vital:19948
- Description: Many well-known studies on leadership have ignored the perspective of women yet bear an emphasis on the importance of portraying leadership in its entirety. This would mean that all leadership perspectives are included and that leaders are allowed to speak for themselves and about themselves. It is this connection I have sought to establish how women perceive leadership by relating the experiences of four women in school principalship. I have used a factual questionnaire to establish the background of each one but, it is the in-depth interviews that yield the leadership perceptions. Borrowing from phenomenological procedures, the leadership experiences are related as Natural Meaning Units (NMUS) whereby all prior knowledge and possible bias are bracketed out. Reinforced by their journal entries, it is only the voice of the women that is heard. My study reinforces the observation of researchers and feminist scholars that women leaders are not only marginalised but also viewed from a perspective that is not their own. From the study, however, the one element about leadership that emerges as unique is the functioning of transformational leadership elements among women leaders in educational set-ups that are inherently traditional, bureaucratic and hierarchical. This is significant because there is an indication that women leaders are inclined to transformational leadership because it favours their feminine qualities. There is also evidence that school principals can embrace leadership diversity and finally, that leadership and the structures of leadership operation are not developed from without but from within the person of the leader and this is an incorporation of their vision and beliefs. In the context of South Africa, this study should be of potential significance because of the change that is taking place in the development and training of school principals.
- Full Text:
- Date Issued: 2000
The role of information technology in the management of records in the Department of Sports, Recreation, Arts and Culture, Eastern Cape
- Authors: Mdingi, Nomaciko
- Date: 2019
- Subjects: Records -- Management Information technology
- Language: English
- Type: Thesis , Masters , M.LIS
- Identifier: http://hdl.handle.net/10353/17630 , vital:41130
- Description: Information Technology (IT) has offered new and different ways in the management of records and distribution of information. Due to IT, records and information are accessed easily, appropriately preserved, quickly retrieved and managed for operational decision-making. Consequently, the main aim of this study was to investigate the role of IT in the management of records with specific reference to the Department of Sports, Recreation, Arts, and Culture, King Williams Town, Eastern Cape. It further examined the types of records created by the department and the current status of its records, compliance to the legal framework for both paper-based and electronic records management, skills and knowledge of staff, archivists and records managers in relation to information technology and the management of electronic records and the constraints the Department of Sports, Recreation, Arts, and Culture encounter in the management of electronic records and recommend possible solutions. One major finding unearthed by this study is that the department is still manually storing records even though the information technology revolution has evolved. The study also found out that the department is faced with a number of challenges when it comes to the responsibility for the implementation of IT in the department. The study put forward a number of recommendations that had to be considered in an attempt to help the department and its employees manage electronic records and tone is mentioned here as this is a prerequisite. It will be beneficial if all the officials that deal with records take the course on records and archives management in institutions like University of Fort Hare so that they know more about the management of records as a whole package.
- Full Text:
- Date Issued: 2019
- Authors: Mdingi, Nomaciko
- Date: 2019
- Subjects: Records -- Management Information technology
- Language: English
- Type: Thesis , Masters , M.LIS
- Identifier: http://hdl.handle.net/10353/17630 , vital:41130
- Description: Information Technology (IT) has offered new and different ways in the management of records and distribution of information. Due to IT, records and information are accessed easily, appropriately preserved, quickly retrieved and managed for operational decision-making. Consequently, the main aim of this study was to investigate the role of IT in the management of records with specific reference to the Department of Sports, Recreation, Arts, and Culture, King Williams Town, Eastern Cape. It further examined the types of records created by the department and the current status of its records, compliance to the legal framework for both paper-based and electronic records management, skills and knowledge of staff, archivists and records managers in relation to information technology and the management of electronic records and the constraints the Department of Sports, Recreation, Arts, and Culture encounter in the management of electronic records and recommend possible solutions. One major finding unearthed by this study is that the department is still manually storing records even though the information technology revolution has evolved. The study also found out that the department is faced with a number of challenges when it comes to the responsibility for the implementation of IT in the department. The study put forward a number of recommendations that had to be considered in an attempt to help the department and its employees manage electronic records and tone is mentioned here as this is a prerequisite. It will be beneficial if all the officials that deal with records take the course on records and archives management in institutions like University of Fort Hare so that they know more about the management of records as a whole package.
- Full Text:
- Date Issued: 2019
'n Leesmoontlikheid van Jeanne Goosen se teks Louoond : die vrou as skrywer binne die Suid-Afrikaanse bestel
- Authors: Viljoen, Erika Valeska
- Date: 1989
- Subjects: Goosen, Jeanne -- Criticism and interpretation , Goosen, Jeanne -- Louoond
- Language: Afrikaans
- Type: Thesis , Masters , MA
- Identifier: vital:3573 , http://hdl.handle.net/10962/d1002096 , Goosen, Jeanne -- Criticism and interpretation , Goosen, Jeanne -- Louoond
- Description: This thesis investigates the narrative strategies of Jeanne Goosen, as employed in her short novel, Louoond. I regard this text as an excellent example of modern Afrikaans prose, and particular reference was made to her previous novel: Om 'n mens na te boots which indicates similarities to the text under scrutiny. Chapter One is a close reading of the first chapter of the novel, in order to identify certain prominent codes, and also to determine what the text itself prescribes. My presumption is that the text determines how it should be read, that no single, predetermined strategy can be rigidly applied to it. Thus I formulated my own individual possible reading from the first chapter, and I view it throughout as mere "speculation", since this possible reading remains only a possibility. Chapter Two contains the theoretical background that is necessary for a scientific study of this kind. I followed mainly the strategies of Roland Barthes and Jacques Derrida, who are pioneers in the post -modernistic theory. It was particularly important to investigate the role of the narrator: the narrator in Louoond presents herself as a writer, therefore it is the process that is paramount. In Chapter Three the code of writing, as identified in Chapter ʺOneʺ of Louoond, is followed closely throughout the text. In Louoond, which is metatextual, violence is textually inherent, and also part of the process of writing. This violence is definitely also part of the South African situation as it is signified in the novel. Throughout the narrator is in a state of tension about her own role in the ʺrevolutionʺ - in which also her own text is a revolution in language, but always within the NOW of South Africa. Chapter Four concerns itself mainly with the role of the woman as narrator, as muse, as primary protagonist. I discuss the code of woman in relation to prominent feminist writers, but it remains in context of the text. Each issue is in the first place determined by the text, the text therefore determines which feminist issues will be investigated. The South African situation, and specifically the Afrikaner situation, serves throughout as intertext for Louoond, as with the code of writing. Other intertextual references are important, because the text is never independent from anything outside itself, and could not exist in such independence. Music plays an important role, with Callas as muse and as fellow female artist, while George Sand functions as fellow writer. Woman, independent of man, is put forward as creator. In my reading, the text remains in the first place a fabrication/imitation of the South African reality, and the fInal scene reaffirms the ʺfinal catastropheʺ that is indicated in the motto as a ʺcondition of controlled hysteriaʺ
- Full Text:
- Date Issued: 1989
- Authors: Viljoen, Erika Valeska
- Date: 1989
- Subjects: Goosen, Jeanne -- Criticism and interpretation , Goosen, Jeanne -- Louoond
- Language: Afrikaans
- Type: Thesis , Masters , MA
- Identifier: vital:3573 , http://hdl.handle.net/10962/d1002096 , Goosen, Jeanne -- Criticism and interpretation , Goosen, Jeanne -- Louoond
- Description: This thesis investigates the narrative strategies of Jeanne Goosen, as employed in her short novel, Louoond. I regard this text as an excellent example of modern Afrikaans prose, and particular reference was made to her previous novel: Om 'n mens na te boots which indicates similarities to the text under scrutiny. Chapter One is a close reading of the first chapter of the novel, in order to identify certain prominent codes, and also to determine what the text itself prescribes. My presumption is that the text determines how it should be read, that no single, predetermined strategy can be rigidly applied to it. Thus I formulated my own individual possible reading from the first chapter, and I view it throughout as mere "speculation", since this possible reading remains only a possibility. Chapter Two contains the theoretical background that is necessary for a scientific study of this kind. I followed mainly the strategies of Roland Barthes and Jacques Derrida, who are pioneers in the post -modernistic theory. It was particularly important to investigate the role of the narrator: the narrator in Louoond presents herself as a writer, therefore it is the process that is paramount. In Chapter Three the code of writing, as identified in Chapter ʺOneʺ of Louoond, is followed closely throughout the text. In Louoond, which is metatextual, violence is textually inherent, and also part of the process of writing. This violence is definitely also part of the South African situation as it is signified in the novel. Throughout the narrator is in a state of tension about her own role in the ʺrevolutionʺ - in which also her own text is a revolution in language, but always within the NOW of South Africa. Chapter Four concerns itself mainly with the role of the woman as narrator, as muse, as primary protagonist. I discuss the code of woman in relation to prominent feminist writers, but it remains in context of the text. Each issue is in the first place determined by the text, the text therefore determines which feminist issues will be investigated. The South African situation, and specifically the Afrikaner situation, serves throughout as intertext for Louoond, as with the code of writing. Other intertextual references are important, because the text is never independent from anything outside itself, and could not exist in such independence. Music plays an important role, with Callas as muse and as fellow female artist, while George Sand functions as fellow writer. Woman, independent of man, is put forward as creator. In my reading, the text remains in the first place a fabrication/imitation of the South African reality, and the fInal scene reaffirms the ʺfinal catastropheʺ that is indicated in the motto as a ʺcondition of controlled hysteriaʺ
- Full Text:
- Date Issued: 1989
The design of an urban hydroponicum: an urban agriculture facility that remediates polluted storm water by utilizing biomimetic processes, that enables vast amounts of food to be grown
- Authors: Bagg, Timothy Kyle
- Date: 2017
- Subjects: Architecture, Industrial -- South Africa -- Port Elizabeth Architecture -- South Africa -- Port Elizabeth -- 21st century , Sustainable buildings Sustainable urban development
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/38783 , vital:34965
- Description: This treatise is founded in a belief that urban ecosystems should not be separate from natural ones and seeks to find ways in which existing urban systems can be reintegrated. This reintegration will be two-fold, providing a remedy for ecologically destructive urban systems as well as providing an opportunity to develop a holistic and sustainable alternative to current practices that generate waste and pollution. The treatise will focus on the management of polluted storm water, specifically along the Walmer catchment area which flows east into Airport Valley and Shark River Valley, and ways in which horticulture building systems can be utilised to achieve remedial action naturally, producing vast amounts of nutritious food for the surrounding community in the process. Impetus for this topic grew out of a concern that the author has for the current state of sustainable practices within South Africa, specifically regarding the relationship between water and agriculture (food). 60 – 70% of South Africa’s water demand is agricultural, with poor water management infrastructure and the current drought severely affecting the agricultural output (food supply) of the country. The increased demand puts immense pressure on South African farmers who have dwindling arable land and less water with which to cultivate crops. South Africa’s population is two thirds urbanised, meaning that most of the population lives in urban centres around the country. This treatise proposes that water-wise urban agricultural systems could be utilised to further cement food and water security in an urban setting by supplementing the food supply chain with local, city-grown produce. The research conducted will generate an architectural and urban intervention that marries the natural with the built environment in a strategically and intentionally designed relationship that exploits synergies between these two environments.
- Full Text:
- Date Issued: 2017
- Authors: Bagg, Timothy Kyle
- Date: 2017
- Subjects: Architecture, Industrial -- South Africa -- Port Elizabeth Architecture -- South Africa -- Port Elizabeth -- 21st century , Sustainable buildings Sustainable urban development
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/38783 , vital:34965
- Description: This treatise is founded in a belief that urban ecosystems should not be separate from natural ones and seeks to find ways in which existing urban systems can be reintegrated. This reintegration will be two-fold, providing a remedy for ecologically destructive urban systems as well as providing an opportunity to develop a holistic and sustainable alternative to current practices that generate waste and pollution. The treatise will focus on the management of polluted storm water, specifically along the Walmer catchment area which flows east into Airport Valley and Shark River Valley, and ways in which horticulture building systems can be utilised to achieve remedial action naturally, producing vast amounts of nutritious food for the surrounding community in the process. Impetus for this topic grew out of a concern that the author has for the current state of sustainable practices within South Africa, specifically regarding the relationship between water and agriculture (food). 60 – 70% of South Africa’s water demand is agricultural, with poor water management infrastructure and the current drought severely affecting the agricultural output (food supply) of the country. The increased demand puts immense pressure on South African farmers who have dwindling arable land and less water with which to cultivate crops. South Africa’s population is two thirds urbanised, meaning that most of the population lives in urban centres around the country. This treatise proposes that water-wise urban agricultural systems could be utilised to further cement food and water security in an urban setting by supplementing the food supply chain with local, city-grown produce. The research conducted will generate an architectural and urban intervention that marries the natural with the built environment in a strategically and intentionally designed relationship that exploits synergies between these two environments.
- Full Text:
- Date Issued: 2017
Effective management of an information technology professional's career
- Authors: Tedder, Derek
- Date: 2005
- Subjects: Information technology -- Vocational guidance , Information technology -- Management , Knowledge management , Career development , Computer Science -- Vocational guidance , System analysis -- Vocational guidance
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1148 , http://hdl.handle.net/10962/d1004543 , Information technology -- Vocational guidance , Information technology -- Management , Knowledge management , Career development , Computer Science -- Vocational guidance , System analysis -- Vocational guidance
- Description: The human resource is constantly cited as an organisation's greatest asset. In a rapidly changing technological environment this is most applicable to the Information Technology (IT) function. Organisations are experiencing IT human resource problems such as low satisfaction, early plateauing, high turnover, burnout, limited advancement potential, nominal corporate commitment, supervisory aversion, poor organisational culture, and exceptional compensation. These problems are directly related to the IT professional's career. There is a lack of information and awareness surrounding IT careers to deal effectively with these problems. The research aims to create increased awareness of IT careers and the inherent problems through the development of a career management model. The research aims to identify the factors that influence IT careers, provide career management with a means to measure compatibility of the factors, and suggest solutions to incompatibility. The solving of this problem will be of mutual benefit to both organisations and individuals as they seek to better manage IT careers. After reviewing research literature relating to career anchors, IT job types, IT skills portfolios, and career dynamics a model for Effective IT Career Management (EITCM) has been constructed. The model represents the dynamic interactions between individual, organisational, and dependent factors. The model examines the compatibility of these interacting factors by measuring the levels of relevant career variables. The model suggests appropriate career management techniques to increase the compatibility of the interacting factors. An empirical study was designed and launched online to provide data that would confirm the seven Critical Success Factors (CSF) relating to the proposed model. The responses from the members of the Computer Society of South Africa (CSSA) allowed the seven hypotheses derived from the CSFs to be tested. The results of the empirical study were positive but required modification to five of the CSFs before they could be confirmed. The EITCM model was modified to reflect the improved CSFs. An awareness of career influencing factors combined with active career management is advantageous to both IT professionals and their organisations.
- Full Text:
- Date Issued: 2005
- Authors: Tedder, Derek
- Date: 2005
- Subjects: Information technology -- Vocational guidance , Information technology -- Management , Knowledge management , Career development , Computer Science -- Vocational guidance , System analysis -- Vocational guidance
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1148 , http://hdl.handle.net/10962/d1004543 , Information technology -- Vocational guidance , Information technology -- Management , Knowledge management , Career development , Computer Science -- Vocational guidance , System analysis -- Vocational guidance
- Description: The human resource is constantly cited as an organisation's greatest asset. In a rapidly changing technological environment this is most applicable to the Information Technology (IT) function. Organisations are experiencing IT human resource problems such as low satisfaction, early plateauing, high turnover, burnout, limited advancement potential, nominal corporate commitment, supervisory aversion, poor organisational culture, and exceptional compensation. These problems are directly related to the IT professional's career. There is a lack of information and awareness surrounding IT careers to deal effectively with these problems. The research aims to create increased awareness of IT careers and the inherent problems through the development of a career management model. The research aims to identify the factors that influence IT careers, provide career management with a means to measure compatibility of the factors, and suggest solutions to incompatibility. The solving of this problem will be of mutual benefit to both organisations and individuals as they seek to better manage IT careers. After reviewing research literature relating to career anchors, IT job types, IT skills portfolios, and career dynamics a model for Effective IT Career Management (EITCM) has been constructed. The model represents the dynamic interactions between individual, organisational, and dependent factors. The model examines the compatibility of these interacting factors by measuring the levels of relevant career variables. The model suggests appropriate career management techniques to increase the compatibility of the interacting factors. An empirical study was designed and launched online to provide data that would confirm the seven Critical Success Factors (CSF) relating to the proposed model. The responses from the members of the Computer Society of South Africa (CSSA) allowed the seven hypotheses derived from the CSFs to be tested. The results of the empirical study were positive but required modification to five of the CSFs before they could be confirmed. The EITCM model was modified to reflect the improved CSFs. An awareness of career influencing factors combined with active career management is advantageous to both IT professionals and their organisations.
- Full Text:
- Date Issued: 2005
Malarial drug targets cysteine proteases as hemoglobinases
- Authors: Mokoena, Fortunate
- Date: 2012
- Subjects: Malaria -- Chemotherapy , Antimalarials , Hemoglobin , Proteolytic enzymes , Cysteine proteinases , Plasmodium falciparum , Plasmodium vivax , Papain
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4005 , http://hdl.handle.net/10962/d1004065 , Malaria -- Chemotherapy , Antimalarials , Hemoglobin , Proteolytic enzymes , Cysteine proteinases , Plasmodium falciparum , Plasmodium vivax , Papain
- Description: Malaria has consistently been rated as the worst parasitic disease in the world. This disease affects an estimated 5 billion households annually. Malaria has a high mortality rate leading to distorted socio-economic development of the world at large. The major challenge pertaining to malaria is its continuous and rapid spread together with the emergence of drug resistance in Plasmodium species (vector agent of the disease). For this reason, researchers throughout the world are following new leads for possible drug targets and therefore, investigating ways of curbing the spread of the disease. Cysteine proteases have emerged as potential antimalarial chemotherapeutic targets. These particular proteases are found in all living organisms, Plasmodium cysteine proteases are known to degrade host hemoglobin during the life cycle of the parasite within the human host. The main objective of this study was to use various in silico methods to analyze the hemoglobinase function of cysteine proteases in P. falciparum and P. vivax. Falcipain-2 (FP2) of P. falciparum is the best characterized of these enzymes, it is a validated drug target. Both the three-dimensional structures of FP2 and its close homologue falcipain-3 (FP3) have been solved by the experimental technique X-ray crystallography. However, the homologue falcipain-2 (FP2’)’ and orthologues from P.vivax vivapain-2 (VP2) and vivapain-3 (VP3) have yet to be elucidated by experimental techniques. In an effort to achieve the principal goal of the study, homology models of the protein structures not already elucidated by experimental methods (FP2’, VP2 and VP3) were calculated using the well known spatial restraint program MODELLER. The derived models, FP2 and FP3 were docked to hemoglobin (their natural substrate). The protein-protein docking was done using the unbound docking program ZDOCK. The substrate-enzyme interactions were analyzed and amino acids involved in binding were observed. It is anticipated that the results obtained from the study will help focus inhibitor design for potential drugs against malaria. The residues found in both the P. falciparum and P. vivax cysteine proteases involved in hemoglobin binding have been identified and some of these are proposed to be the main focus for the design of a peptidomimetric inhibitor.
- Full Text:
- Date Issued: 2012
- Authors: Mokoena, Fortunate
- Date: 2012
- Subjects: Malaria -- Chemotherapy , Antimalarials , Hemoglobin , Proteolytic enzymes , Cysteine proteinases , Plasmodium falciparum , Plasmodium vivax , Papain
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4005 , http://hdl.handle.net/10962/d1004065 , Malaria -- Chemotherapy , Antimalarials , Hemoglobin , Proteolytic enzymes , Cysteine proteinases , Plasmodium falciparum , Plasmodium vivax , Papain
- Description: Malaria has consistently been rated as the worst parasitic disease in the world. This disease affects an estimated 5 billion households annually. Malaria has a high mortality rate leading to distorted socio-economic development of the world at large. The major challenge pertaining to malaria is its continuous and rapid spread together with the emergence of drug resistance in Plasmodium species (vector agent of the disease). For this reason, researchers throughout the world are following new leads for possible drug targets and therefore, investigating ways of curbing the spread of the disease. Cysteine proteases have emerged as potential antimalarial chemotherapeutic targets. These particular proteases are found in all living organisms, Plasmodium cysteine proteases are known to degrade host hemoglobin during the life cycle of the parasite within the human host. The main objective of this study was to use various in silico methods to analyze the hemoglobinase function of cysteine proteases in P. falciparum and P. vivax. Falcipain-2 (FP2) of P. falciparum is the best characterized of these enzymes, it is a validated drug target. Both the three-dimensional structures of FP2 and its close homologue falcipain-3 (FP3) have been solved by the experimental technique X-ray crystallography. However, the homologue falcipain-2 (FP2’)’ and orthologues from P.vivax vivapain-2 (VP2) and vivapain-3 (VP3) have yet to be elucidated by experimental techniques. In an effort to achieve the principal goal of the study, homology models of the protein structures not already elucidated by experimental methods (FP2’, VP2 and VP3) were calculated using the well known spatial restraint program MODELLER. The derived models, FP2 and FP3 were docked to hemoglobin (their natural substrate). The protein-protein docking was done using the unbound docking program ZDOCK. The substrate-enzyme interactions were analyzed and amino acids involved in binding were observed. It is anticipated that the results obtained from the study will help focus inhibitor design for potential drugs against malaria. The residues found in both the P. falciparum and P. vivax cysteine proteases involved in hemoglobin binding have been identified and some of these are proposed to be the main focus for the design of a peptidomimetric inhibitor.
- Full Text:
- Date Issued: 2012
Lead-radium dating of two deep-water fishes from the southern hemisphere, Patagonian toothfish (Dissostichus eleginoides) and Orange Roughy (Hoplostethus atlanticus)
- Authors: Andrews, Allen Hia
- Date: 2009
- Subjects: Fishes -- Age determination , Fishes -- Southern hemisphere -- Longevity , Fishes -- Growth , Radioactive dating , Patagonian toothfish , Patagonian toothfish -- Fisheries , Orange roughy , Orange roughy -- Fisheries , Deep-sea fishes -- Southern hemisphere , Deep-sea fisheries , Deep-sea fisheries -- Southern hemisphere
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5295 , http://hdl.handle.net/10962/d1005140
- Description: Patagonian toothfish (Dissostichus eleginoides) or "Chilean sea bass" support a valuable and controversial fishery, but the life history is little known and longevity estimates range from ~20 to more than 40 or 50 yr. In this study, lead-radium dating provided validated age estimates from juveniles to older adults, supporting the use of otoliths as accurate indicators of age. The oldest age groups were near 30 yr, which provided support for age estimates exceeding 40 or 50 yr from grow zone counts in otolith sections. Hence, scale reading, which rarely exceeds 20 years, has the potential for age underestimation. Lead-radium dating revealed what may be minor differences in age interpretation between two facilities and findings may provide an age-validated opportunity for the CCAMLR Otolith Network to reassess otolith interpretations. Orange roughy (Hoplostethus atlanticus) support a major deep-sea fishery and stock assessments often depend on age analyses, but lifespan estimates range from ~20 to over 100 yr and validation of growth zone counts remained unresolved. An early application of lead-radium dating supported centenarian ages, but the findings were met with disbelief and some studies have attempted to discredit the technique and the long lifespan. In this study, an improved lead-radium dating technique used smaller samples than previously possible and circumvented assumptions that were previously necessary. Lead-radium dating of otolith cores, the first few years of growth, provided ratios that correlated well with the ingrowth curve. This provided robust support for age estimates from otolith thin sections. Use of radiometric ages as independent age estimates indicated the fish in the oldest group were at least 93 yr. Lead-radium dating has validated a centenarian lifespan for orange roughy. To date, radium-226 has been measured in otoliths of 39 fish species ranging from the northern Pacific and Atlantic Oceans to the Southern Ocean. In total, 367 reliable radium-226 measurements were made in 36 studies since the first lead-radium dating study on fish in 1982. The activity of radium-226 measurements ranged over 3 orders of magnitude (<0.001 to >1.0 dpm.g⁻¹). An analysis revealed ontogenetic differences in radium-226 uptake that may be attributed to changes in habitat or diet. Radiometric age from otolith core studies was used to describe a radium-226 uptake time-series for some species, which revealed interesting patterns over long periods. This synopsis provides information on the uptake of radium-226 to otoliths from an environmental perspective, which can be used as a basis for future studies.
- Full Text:
- Date Issued: 2009
- Authors: Andrews, Allen Hia
- Date: 2009
- Subjects: Fishes -- Age determination , Fishes -- Southern hemisphere -- Longevity , Fishes -- Growth , Radioactive dating , Patagonian toothfish , Patagonian toothfish -- Fisheries , Orange roughy , Orange roughy -- Fisheries , Deep-sea fishes -- Southern hemisphere , Deep-sea fisheries , Deep-sea fisheries -- Southern hemisphere
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5295 , http://hdl.handle.net/10962/d1005140
- Description: Patagonian toothfish (Dissostichus eleginoides) or "Chilean sea bass" support a valuable and controversial fishery, but the life history is little known and longevity estimates range from ~20 to more than 40 or 50 yr. In this study, lead-radium dating provided validated age estimates from juveniles to older adults, supporting the use of otoliths as accurate indicators of age. The oldest age groups were near 30 yr, which provided support for age estimates exceeding 40 or 50 yr from grow zone counts in otolith sections. Hence, scale reading, which rarely exceeds 20 years, has the potential for age underestimation. Lead-radium dating revealed what may be minor differences in age interpretation between two facilities and findings may provide an age-validated opportunity for the CCAMLR Otolith Network to reassess otolith interpretations. Orange roughy (Hoplostethus atlanticus) support a major deep-sea fishery and stock assessments often depend on age analyses, but lifespan estimates range from ~20 to over 100 yr and validation of growth zone counts remained unresolved. An early application of lead-radium dating supported centenarian ages, but the findings were met with disbelief and some studies have attempted to discredit the technique and the long lifespan. In this study, an improved lead-radium dating technique used smaller samples than previously possible and circumvented assumptions that were previously necessary. Lead-radium dating of otolith cores, the first few years of growth, provided ratios that correlated well with the ingrowth curve. This provided robust support for age estimates from otolith thin sections. Use of radiometric ages as independent age estimates indicated the fish in the oldest group were at least 93 yr. Lead-radium dating has validated a centenarian lifespan for orange roughy. To date, radium-226 has been measured in otoliths of 39 fish species ranging from the northern Pacific and Atlantic Oceans to the Southern Ocean. In total, 367 reliable radium-226 measurements were made in 36 studies since the first lead-radium dating study on fish in 1982. The activity of radium-226 measurements ranged over 3 orders of magnitude (<0.001 to >1.0 dpm.g⁻¹). An analysis revealed ontogenetic differences in radium-226 uptake that may be attributed to changes in habitat or diet. Radiometric age from otolith core studies was used to describe a radium-226 uptake time-series for some species, which revealed interesting patterns over long periods. This synopsis provides information on the uptake of radium-226 to otoliths from an environmental perspective, which can be used as a basis for future studies.
- Full Text:
- Date Issued: 2009
Evaluation of pre-treatment methods on production of bioethanol from bagasse and sugarcane trash
- Authors: Dodo, Charlie Marembo
- Date: 2019
- Subjects: Lignocellulose
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15387 , vital:40403
- Description: A variety of methods have been researched on for bioethanol preparation from different feedstocks. Amongst the available feedstock, one such feedstock is the sugarcane plant. In most of the research on bioethanol preparation with sugarcane the sugary juice has been widely used, with the bagasse and trash having been discarded as waste. The “waste” bagasse and trash are usually removed and thrown away or burnt during harvesting or in sugar mills to supplement energy requirements. This research on lignocellulosic bagasse and trash was done so as not to discard them but to rather find ways in which to use this biomass constructively. Alternatives to burning that can potentially add value to this biomass need to be researched on by evaluating their hydrolysis content. The different lignocellulose pretreatment methods of concentrated and dilute acid pretreatment, with subsequent enzyme hydrolysis as well as alkali and oxidative alkali pretreatment with enzyme hydrolysis were experimented on the bagasse and trash for hydrolysis efficiency and effectiveness. There are two types of acid hydrolysis which were investigated on which are concentrated and dilute sulphuric acid pretreatments. Use of concentrated sulphuric acid yielded the highest amounts of reducing sugars but also resulted in the highest amounts of downstream process inhibitors formation. This resulted in the need for neutralisation steps which in turn increase the overall costs of using this method to obtain reducing sugars. It has however the advantage of occurring at a faster rate, within minutes or hours, than using biological enzymes which took days, up to 72 hours to obtain the highest reducing sugar amounts. Dilute sulphuric acid pretreatment offered the advantage of using fewer chemicals which are therefore less severe on equipment and result in fewer fermentation inhibitors being formed. Dilute sulphuric acid hydrolysis also takes a relatively shorter period than biological methods of pretreatment. A challenge of fermentation inhibitors formed during acid hydrolysis was countered by using the methods of overliming (calcium hydroxide) and comparing it to neutralization with sodium hydroxide. Alkali pretreatment with sodium hydroxide was researched on by applying different pretreatment concentrations during experiments on the lignocellulosic biomass. There was an increase in the available quantities of cellulose with a significant reduction in lignin with pretreatment. Alkali pretreatment proved effective in exposing the cellulose which made v more cellulose surface area available to cellulase enzymes for enzyme hydrolysis. The highest yield of reducing sugars was obtained from hydrolysates pretreated with 0.25 M sodium hydroxide for 60 min and a period of 72 h of enzyme hydrolysis. In general the longer the pretreatment time the more reducing sugars were produced from the enzyme hydrolysis. Alkali peroxide pretreatment also resulted in significant reductions in lignin quantities of lignocellulose material. In this method sodium hydroxide in combination with hydrogen peroxide were used in pretreating the biomass. Hydrolysates with even fewer fermentation inhibitors were produced as a result. The highest percentage concentration of cellulose of 63% (g/g) was achieved after pretreatment of bagasse with 5% alkali hydrogen peroxide and trash with 0,25M sodium hydroxide pretreatment. Pretreatment of biomass using alkali with subsequent enzymatic hydrolysis gave the highest yields of fermentable sugars of 38% (g/g) using 7% (v/v) alkali peroxide pre-treated trash than 36% (g/g) for 5% (v/v) with the least inhibitors. Reducing sugar yields of 25% (g/g) and 22% (g/g) were obtained after pretreatment with concentrated and dilute acid respectively. Neutralization of the acid hydrolysates was necessary to reduce inhibitors formed with neutralisation by sodium hydroxide resulting in low dilutions and loss of fermentable sugars as unlike in the case of overliming. Subsequent steps of fermenting the reducing sugars resulting from pretreatment into bioethanol were based on using the yeast Saccharomyces cerevisae. Pretreatment hydrolysates from alkali peroxide experiments produced higher bioethanol yields of 13.7 (g/l) after enzyme hydrolysates versus 6.9 (g/l) bioethanol from dilute acid hydrolyzates. A comparison of the effects of time showed there was more bioethanol yield of 13.7 (g/l) after 72 h of fermentation with the yeast versus 7.0 (g/l) bioethanol after pretreatment for 24 h. The only drawback is the longer fermentation period which thus reduces the process and so reduces the value of the increase in yield
- Full Text:
- Date Issued: 2019
- Authors: Dodo, Charlie Marembo
- Date: 2019
- Subjects: Lignocellulose
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15387 , vital:40403
- Description: A variety of methods have been researched on for bioethanol preparation from different feedstocks. Amongst the available feedstock, one such feedstock is the sugarcane plant. In most of the research on bioethanol preparation with sugarcane the sugary juice has been widely used, with the bagasse and trash having been discarded as waste. The “waste” bagasse and trash are usually removed and thrown away or burnt during harvesting or in sugar mills to supplement energy requirements. This research on lignocellulosic bagasse and trash was done so as not to discard them but to rather find ways in which to use this biomass constructively. Alternatives to burning that can potentially add value to this biomass need to be researched on by evaluating their hydrolysis content. The different lignocellulose pretreatment methods of concentrated and dilute acid pretreatment, with subsequent enzyme hydrolysis as well as alkali and oxidative alkali pretreatment with enzyme hydrolysis were experimented on the bagasse and trash for hydrolysis efficiency and effectiveness. There are two types of acid hydrolysis which were investigated on which are concentrated and dilute sulphuric acid pretreatments. Use of concentrated sulphuric acid yielded the highest amounts of reducing sugars but also resulted in the highest amounts of downstream process inhibitors formation. This resulted in the need for neutralisation steps which in turn increase the overall costs of using this method to obtain reducing sugars. It has however the advantage of occurring at a faster rate, within minutes or hours, than using biological enzymes which took days, up to 72 hours to obtain the highest reducing sugar amounts. Dilute sulphuric acid pretreatment offered the advantage of using fewer chemicals which are therefore less severe on equipment and result in fewer fermentation inhibitors being formed. Dilute sulphuric acid hydrolysis also takes a relatively shorter period than biological methods of pretreatment. A challenge of fermentation inhibitors formed during acid hydrolysis was countered by using the methods of overliming (calcium hydroxide) and comparing it to neutralization with sodium hydroxide. Alkali pretreatment with sodium hydroxide was researched on by applying different pretreatment concentrations during experiments on the lignocellulosic biomass. There was an increase in the available quantities of cellulose with a significant reduction in lignin with pretreatment. Alkali pretreatment proved effective in exposing the cellulose which made v more cellulose surface area available to cellulase enzymes for enzyme hydrolysis. The highest yield of reducing sugars was obtained from hydrolysates pretreated with 0.25 M sodium hydroxide for 60 min and a period of 72 h of enzyme hydrolysis. In general the longer the pretreatment time the more reducing sugars were produced from the enzyme hydrolysis. Alkali peroxide pretreatment also resulted in significant reductions in lignin quantities of lignocellulose material. In this method sodium hydroxide in combination with hydrogen peroxide were used in pretreating the biomass. Hydrolysates with even fewer fermentation inhibitors were produced as a result. The highest percentage concentration of cellulose of 63% (g/g) was achieved after pretreatment of bagasse with 5% alkali hydrogen peroxide and trash with 0,25M sodium hydroxide pretreatment. Pretreatment of biomass using alkali with subsequent enzymatic hydrolysis gave the highest yields of fermentable sugars of 38% (g/g) using 7% (v/v) alkali peroxide pre-treated trash than 36% (g/g) for 5% (v/v) with the least inhibitors. Reducing sugar yields of 25% (g/g) and 22% (g/g) were obtained after pretreatment with concentrated and dilute acid respectively. Neutralization of the acid hydrolysates was necessary to reduce inhibitors formed with neutralisation by sodium hydroxide resulting in low dilutions and loss of fermentable sugars as unlike in the case of overliming. Subsequent steps of fermenting the reducing sugars resulting from pretreatment into bioethanol were based on using the yeast Saccharomyces cerevisae. Pretreatment hydrolysates from alkali peroxide experiments produced higher bioethanol yields of 13.7 (g/l) after enzyme hydrolysates versus 6.9 (g/l) bioethanol from dilute acid hydrolyzates. A comparison of the effects of time showed there was more bioethanol yield of 13.7 (g/l) after 72 h of fermentation with the yeast versus 7.0 (g/l) bioethanol after pretreatment for 24 h. The only drawback is the longer fermentation period which thus reduces the process and so reduces the value of the increase in yield
- Full Text:
- Date Issued: 2019
An evaluation of knowledge sharing as a knowledge management mechanism in public libraries in Cape Town, Western Cape Province , South Africa
- Authors: Tatana, Vuyokazi
- Date: 2015
- Subjects: Knowledge management Information services Organizational learning
- Language: English
- Type: Thesis , Masters , Degree
- Identifier: http://hdl.handle.net/10353/5138 , vital:29090
- Description: This study aimed to investigate into knowledge sharing as a mechanism for managing knowledge in the City of Cape Town public libraries, Western Cape, South Africa. The study sought to achieve the following objectives: To find out the extent to which knowledge sharing takes place in the City of Cape Town public libraries; To establish how knowledge is shared between the less experienced and the more experienced librarians; To explore the influence of knowledge sharing on service delivery in the City of Cape Town public libraries; To identify and discuss the impediments to knowledge sharing the City of Cape Town public libraries; The findings of the study would provide insight useful in addressing the challenges that confront public libraries as far as knowledge sharing and is concerned. This study would assist to maintain the best practices of knowledge sharing in the City of Cape Town public libraries.This study would also help the City of Cape Town policy makers and library management to come up with knowledge‐sharing/ knowledge management intervention measures from an informed point of view.
- Full Text:
- Date Issued: 2015
- Authors: Tatana, Vuyokazi
- Date: 2015
- Subjects: Knowledge management Information services Organizational learning
- Language: English
- Type: Thesis , Masters , Degree
- Identifier: http://hdl.handle.net/10353/5138 , vital:29090
- Description: This study aimed to investigate into knowledge sharing as a mechanism for managing knowledge in the City of Cape Town public libraries, Western Cape, South Africa. The study sought to achieve the following objectives: To find out the extent to which knowledge sharing takes place in the City of Cape Town public libraries; To establish how knowledge is shared between the less experienced and the more experienced librarians; To explore the influence of knowledge sharing on service delivery in the City of Cape Town public libraries; To identify and discuss the impediments to knowledge sharing the City of Cape Town public libraries; The findings of the study would provide insight useful in addressing the challenges that confront public libraries as far as knowledge sharing and is concerned. This study would assist to maintain the best practices of knowledge sharing in the City of Cape Town public libraries.This study would also help the City of Cape Town policy makers and library management to come up with knowledge‐sharing/ knowledge management intervention measures from an informed point of view.
- Full Text:
- Date Issued: 2015
An assessment of the Auditor General's contribution to good governance in the public service: a case of the Eastern Cape provincial administration
- Authors: Khashe, Sivuyile Churchill
- Date: 2015
- Subjects: Auditing -- South Africa -- Eastern Cape Civil service -- South Africa -- Eastern Cape Public administration -- South Africa -- Eastern Cape Political corruption -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , M Admin
- Identifier: http://hdl.handle.net/10353/1675 , vital:27544
- Description: The Office of the Auditor -General’s role is by no means minor, for it plays a major role in curbing corruption and acts as a ‘’watchdog’’ of the nation over public funds. Amidst high mismanagement and misuse of public resources, as well as corruption, especially in developing countries, the major question one asks is how effective the Auditor -General can be in ensuring good governance within state departments so as to improve service delivery. The gaps between approved budgets and the realisation of policy and development goals stand among key governance challenges in many developing countries. Supreme Audit Institutions (SAIs) play an important role in holding governments to account. However, many SAIs including AGSA face serious challenges when trying to evaluate the expenditures and performance of government agencies. Therefore this study suggests that more resources should be invested in the office of the AG so as to allow it to carry out its duties without impediments. Good governance and public finance accountability is becoming increasingly important in the public sector. One means of effecting good governance and accountability is through auditing. For this reason the Office of the Auditor-General through the Constitution of the Republic of South Africa 1996 (Act 108 of 1996 section 216 (1)) was established to facilitate and encourage good governance and effective accountability through auditing. To this end the study assesses the contribution made by the AGSA in encouraging good governance practices in government departments in the Eastern Cape Province.
- Full Text:
- Date Issued: 2015
- Authors: Khashe, Sivuyile Churchill
- Date: 2015
- Subjects: Auditing -- South Africa -- Eastern Cape Civil service -- South Africa -- Eastern Cape Public administration -- South Africa -- Eastern Cape Political corruption -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , M Admin
- Identifier: http://hdl.handle.net/10353/1675 , vital:27544
- Description: The Office of the Auditor -General’s role is by no means minor, for it plays a major role in curbing corruption and acts as a ‘’watchdog’’ of the nation over public funds. Amidst high mismanagement and misuse of public resources, as well as corruption, especially in developing countries, the major question one asks is how effective the Auditor -General can be in ensuring good governance within state departments so as to improve service delivery. The gaps between approved budgets and the realisation of policy and development goals stand among key governance challenges in many developing countries. Supreme Audit Institutions (SAIs) play an important role in holding governments to account. However, many SAIs including AGSA face serious challenges when trying to evaluate the expenditures and performance of government agencies. Therefore this study suggests that more resources should be invested in the office of the AG so as to allow it to carry out its duties without impediments. Good governance and public finance accountability is becoming increasingly important in the public sector. One means of effecting good governance and accountability is through auditing. For this reason the Office of the Auditor-General through the Constitution of the Republic of South Africa 1996 (Act 108 of 1996 section 216 (1)) was established to facilitate and encourage good governance and effective accountability through auditing. To this end the study assesses the contribution made by the AGSA in encouraging good governance practices in government departments in the Eastern Cape Province.
- Full Text:
- Date Issued: 2015
An assessment of the Auditor General's contribution to good governance in the public service: a case of the Eastern Cape provincial administration
- Authors: Khashe, Sivuyile Churchill
- Date: 2015
- Subjects: Auditing -- South Africa -- Eastern Cape , Civil service -- South Africa -- Eastern Cape Finance, Public -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MPA
- Identifier: http://hdl.handle.net/10353/1654 , vital:27500
- Description: The Office of the Auditor -General’s role is by no means minor, for it plays a major role in curbing corruption and acts as a ‘’watchdog’’ of the nation over public funds. Amidst high mismanagement and misuse of public resources, as well as corruption, especially in developing countries, the major question one asks is how effective the Auditor -General can be in ensuring good governance within state departments so as to improve service delivery. The gaps between approved budgets and the realisation of policy and development goals stand among key governance challenges in many developing countries. Supreme Audit Institutions (SAIs) play an important role in holding governments to account. However, many SAIs including AGSA face serious challenges when trying to evaluate the expenditures and performance of government agencies. Therefore this study suggests that more resources should be invested in the office of the AG so as to allow it to carry out its duties without impediments. Good governance and public finance accountability is becoming increasingly important in the public sector. One means of effecting good governance and accountability is through auditing. For this reason the Office of the Auditor-General through the Constitution of the Republic of South Africa 1996 (Act 108 of 1996 section 216 (1)) was established to facilitate and encourage good governance and effective accountability through auditing.
- Full Text:
- Date Issued: 2015
- Authors: Khashe, Sivuyile Churchill
- Date: 2015
- Subjects: Auditing -- South Africa -- Eastern Cape , Civil service -- South Africa -- Eastern Cape Finance, Public -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MPA
- Identifier: http://hdl.handle.net/10353/1654 , vital:27500
- Description: The Office of the Auditor -General’s role is by no means minor, for it plays a major role in curbing corruption and acts as a ‘’watchdog’’ of the nation over public funds. Amidst high mismanagement and misuse of public resources, as well as corruption, especially in developing countries, the major question one asks is how effective the Auditor -General can be in ensuring good governance within state departments so as to improve service delivery. The gaps between approved budgets and the realisation of policy and development goals stand among key governance challenges in many developing countries. Supreme Audit Institutions (SAIs) play an important role in holding governments to account. However, many SAIs including AGSA face serious challenges when trying to evaluate the expenditures and performance of government agencies. Therefore this study suggests that more resources should be invested in the office of the AG so as to allow it to carry out its duties without impediments. Good governance and public finance accountability is becoming increasingly important in the public sector. One means of effecting good governance and accountability is through auditing. For this reason the Office of the Auditor-General through the Constitution of the Republic of South Africa 1996 (Act 108 of 1996 section 216 (1)) was established to facilitate and encourage good governance and effective accountability through auditing.
- Full Text:
- Date Issued: 2015
Permaculture as an aspect of environmental learning: an investigation into secondary school communities in Zimbabwe
- Authors: Nyika, Mugove Walter
- Date: 2002
- Subjects: Permaculture -- Study and teaching (Secondary) -- Zimbabwe Land use -- Zimbabwe Land use -- Environmental aspects -- Zimbabwe Agriculture -- Zimbabwe Sustainable agriculture -- Zimbabawe
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1960 , http://hdl.handle.net/10962/d1008447
- Description: The Schools and Colleges Permaculture (SCOPE) Programme in Zimbabwe has developed a process for use by schools in planning for the sustainable management of their land. The process is called Integrated Land-Use Design (ILUD) and is based on Permaculture principles. The ILUD process has so far been implemented in 54 pilot schools where it has been used to facilitate the re-design of the school grounds through the active participation of the students, staff and parents. The aim of this research was to investigate what environmental learning takes place during the implementation of the ILUD process and related activities, with a view to informing the improvement of the process. The research was conducted within the interpretive paradigm with particular use being made of the Symbolic Interactionist theoretical framework to explore the social situations in which the ILUD process has been applied. A purposive sample of two schools and five form 4 (grade 11) pupils from each school was selected for the study. The main data collection method was the structured interview. Other data were collected from nonparticipant observations and the analysis of documents, particularly photographs. The data was analysed using the constant comparative method. The findings point towards a significant contribution from the Permaculture activities to the environmental knowledge, environmental management skills and the positive environmental attitudes of the pupils. The work done at the two schools indicates the usefulness of the ILUD process as a tool for environmental action in the schools but its application in the communities was found to be limited by constraints such as lack of resources and the limited capacity of teachers to work in the field of adult education and training. It is recommended that Permaculture should be integrated into the secondary school curriculum if the momentum of the progress made so far is to be maintained. The SCOPE Programme itself needs to be strengthened for its work with communities. There is, for example, a need for adult education and training methods if the introduction of ILUD to the communities is to be successful.
- Full Text:
- Date Issued: 2002
- Authors: Nyika, Mugove Walter
- Date: 2002
- Subjects: Permaculture -- Study and teaching (Secondary) -- Zimbabwe Land use -- Zimbabwe Land use -- Environmental aspects -- Zimbabwe Agriculture -- Zimbabwe Sustainable agriculture -- Zimbabawe
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1960 , http://hdl.handle.net/10962/d1008447
- Description: The Schools and Colleges Permaculture (SCOPE) Programme in Zimbabwe has developed a process for use by schools in planning for the sustainable management of their land. The process is called Integrated Land-Use Design (ILUD) and is based on Permaculture principles. The ILUD process has so far been implemented in 54 pilot schools where it has been used to facilitate the re-design of the school grounds through the active participation of the students, staff and parents. The aim of this research was to investigate what environmental learning takes place during the implementation of the ILUD process and related activities, with a view to informing the improvement of the process. The research was conducted within the interpretive paradigm with particular use being made of the Symbolic Interactionist theoretical framework to explore the social situations in which the ILUD process has been applied. A purposive sample of two schools and five form 4 (grade 11) pupils from each school was selected for the study. The main data collection method was the structured interview. Other data were collected from nonparticipant observations and the analysis of documents, particularly photographs. The data was analysed using the constant comparative method. The findings point towards a significant contribution from the Permaculture activities to the environmental knowledge, environmental management skills and the positive environmental attitudes of the pupils. The work done at the two schools indicates the usefulness of the ILUD process as a tool for environmental action in the schools but its application in the communities was found to be limited by constraints such as lack of resources and the limited capacity of teachers to work in the field of adult education and training. It is recommended that Permaculture should be integrated into the secondary school curriculum if the momentum of the progress made so far is to be maintained. The SCOPE Programme itself needs to be strengthened for its work with communities. There is, for example, a need for adult education and training methods if the introduction of ILUD to the communities is to be successful.
- Full Text:
- Date Issued: 2002
Dispersal of the cochineal insect Dactylopius Austrinus de Lotto (Homoptera : Dactylopiidae)
- Authors: Gunn, Brian Howard
- Date: 1979
- Subjects: Cochineal insect--South Africa , Cochineal insects , Biological control , Jointed cactus , South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5596 , http://hdl.handle.net/10962/d1002046
- Description: Dispersal of the cochineal insect Dactylopius austrinus De Lotto, introduced into South Africa in 1932 as a biological control agent against jointed cactus Opuntia aurantiaca Lindley, was investigated. Zimmermann et al. (l974) suggested that the apparent failure of this insect to control jointed cactus infestations is due to limited dispersal of the first instar nymphs (hereafter referred to as crawlers). Studies on crawler morphology have shown a clear sexual dimorphism in the pattern and development of filaments on the head, thorax and abdomen of male and female crawlers. This enabled differentiation between the sexes with respect to terminal velocities, behaviour and survival of crawlers which have shown that the crawlers, especially the females, are well adapted to dispersal. Long filaments on the head, thorax and abdomen of the female crawlers, that are restricted to dispersal in the crawler stage (as later instars are sessile) and a behaviour directed towards "take-off" enhance the potential for dispersal. The more sedentary males, with long filaments restricted to the abdomen, are able to disperse as winged adults. The principal factors influencing the timing of dispersal and number of crawlers blown from the host plant are wind and temperature; the latter determining the number of crawlers moving on the host plant. Dispersal is confined to the period between 06h00 and 20h00 and it was possible to correlate the pattern of crawler dispersal with wind patterns. The general equation of Taylor (1978) provided an adequate description of horizontal distribution of D.austrinus crawlers in all directions. Wind dispersal of the apterous crawlers is restricted by the low height of jointed cactus plants. Horizontal distribution is limited (generally less than 10 m) although a small proportion of crawlers carried vertically upwards by turbulence or convection currents are sufficiently hardy to survive long range displacement. It is suggested that the small size of the host plant will also reduce effective colonization as the canopy area provides a small target for the wind-blown crawlers. The limitation on dispersal due to the low height of the host plant suggested a system for artificially enhancing crawler dispersal from elevated towers in the field. Evaluation of this system confirmed that it would be practical to augment or introduce cochineal into jointed cactus infestations to enhance the biocontrol potential of this insect. This offers an alternative to chemical control, that has so far failed to control the spread of jointed cactus despite an intensive and expensive herbicide program
- Full Text:
- Date Issued: 1979
- Authors: Gunn, Brian Howard
- Date: 1979
- Subjects: Cochineal insect--South Africa , Cochineal insects , Biological control , Jointed cactus , South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5596 , http://hdl.handle.net/10962/d1002046
- Description: Dispersal of the cochineal insect Dactylopius austrinus De Lotto, introduced into South Africa in 1932 as a biological control agent against jointed cactus Opuntia aurantiaca Lindley, was investigated. Zimmermann et al. (l974) suggested that the apparent failure of this insect to control jointed cactus infestations is due to limited dispersal of the first instar nymphs (hereafter referred to as crawlers). Studies on crawler morphology have shown a clear sexual dimorphism in the pattern and development of filaments on the head, thorax and abdomen of male and female crawlers. This enabled differentiation between the sexes with respect to terminal velocities, behaviour and survival of crawlers which have shown that the crawlers, especially the females, are well adapted to dispersal. Long filaments on the head, thorax and abdomen of the female crawlers, that are restricted to dispersal in the crawler stage (as later instars are sessile) and a behaviour directed towards "take-off" enhance the potential for dispersal. The more sedentary males, with long filaments restricted to the abdomen, are able to disperse as winged adults. The principal factors influencing the timing of dispersal and number of crawlers blown from the host plant are wind and temperature; the latter determining the number of crawlers moving on the host plant. Dispersal is confined to the period between 06h00 and 20h00 and it was possible to correlate the pattern of crawler dispersal with wind patterns. The general equation of Taylor (1978) provided an adequate description of horizontal distribution of D.austrinus crawlers in all directions. Wind dispersal of the apterous crawlers is restricted by the low height of jointed cactus plants. Horizontal distribution is limited (generally less than 10 m) although a small proportion of crawlers carried vertically upwards by turbulence or convection currents are sufficiently hardy to survive long range displacement. It is suggested that the small size of the host plant will also reduce effective colonization as the canopy area provides a small target for the wind-blown crawlers. The limitation on dispersal due to the low height of the host plant suggested a system for artificially enhancing crawler dispersal from elevated towers in the field. Evaluation of this system confirmed that it would be practical to augment or introduce cochineal into jointed cactus infestations to enhance the biocontrol potential of this insect. This offers an alternative to chemical control, that has so far failed to control the spread of jointed cactus despite an intensive and expensive herbicide program
- Full Text:
- Date Issued: 1979
Social assistance strategies as means of addressing poverty: lessons for South Africa
- Authors: Mampuru, Tsebo
- Date: 2016
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/4098 , vital:20607
- Description: Poverty is a daily reality which a majority of South Africans live with. Social security in the form of cash grants has been the main poverty reduction instrument, albeit with limited success. The thesis aims to propose improvements which can be made in the government’s current social protection system and formulate alternative directions towards reducing poverty. An overview of the three most researched social security strategies around the world (i.e. Nordic, Latin American, and U.S. models) revealed two dominant instruments: conditionality and universalism. If applied in South Africa, universalism may be costly and unsustainable unless the right funding method is used. Attaching education and health attainment conditions to an adult grant would be inefficient and even burdensome to recipients. In terms of child grants, there is little evidence to suggest that the demand for and private levels of investment in education and health are insufficient. Therefore attaching health and education conditions to social grants may only serve to highlight the severe supply side inefficiencies in South Africa. Attaching marriage as an alternative condition may disadvantage poor and needy beneficiaries as marriage is an expensive institution in South Africa. Furthermore, enforcing the marriage condition would violate the constitutional rights of recipients who do not necessarily place a high value on the institution. To strengthen the poverty reduction efficiency of social grants and reduce dependency, the thesis suggests that social cash grants, regardless of whether universal and/or conditional or neither, should be temporary and used in conjunction with other strategies which encourage inclusive economic growth. Social assistance alone will not reduce poverty and ultimately, inclusive economic growth remains a more viable approach to reducing poverty. How to achieve the required inclusive economic growth in South Africa therefore provides further research opportunities.
- Full Text:
- Date Issued: 2016
- Authors: Mampuru, Tsebo
- Date: 2016
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/4098 , vital:20607
- Description: Poverty is a daily reality which a majority of South Africans live with. Social security in the form of cash grants has been the main poverty reduction instrument, albeit with limited success. The thesis aims to propose improvements which can be made in the government’s current social protection system and formulate alternative directions towards reducing poverty. An overview of the three most researched social security strategies around the world (i.e. Nordic, Latin American, and U.S. models) revealed two dominant instruments: conditionality and universalism. If applied in South Africa, universalism may be costly and unsustainable unless the right funding method is used. Attaching education and health attainment conditions to an adult grant would be inefficient and even burdensome to recipients. In terms of child grants, there is little evidence to suggest that the demand for and private levels of investment in education and health are insufficient. Therefore attaching health and education conditions to social grants may only serve to highlight the severe supply side inefficiencies in South Africa. Attaching marriage as an alternative condition may disadvantage poor and needy beneficiaries as marriage is an expensive institution in South Africa. Furthermore, enforcing the marriage condition would violate the constitutional rights of recipients who do not necessarily place a high value on the institution. To strengthen the poverty reduction efficiency of social grants and reduce dependency, the thesis suggests that social cash grants, regardless of whether universal and/or conditional or neither, should be temporary and used in conjunction with other strategies which encourage inclusive economic growth. Social assistance alone will not reduce poverty and ultimately, inclusive economic growth remains a more viable approach to reducing poverty. How to achieve the required inclusive economic growth in South Africa therefore provides further research opportunities.
- Full Text:
- Date Issued: 2016
Nonlinear optical studies of metallophtalocyanines and hemiporphyrazines in solution
- Authors: Britton, Jonathan
- Date: 2014
- Subjects: Phthalocyanines Photochemistry Nanoparticles Nanostructured materials Polymers Quantum dots
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4464 , http://hdl.handle.net/10962/d1011608
- Description: This thesis presents the study of the effects of CdTe-TGA quantum dots (QDs) on optical limiting ability of different phthalocyanine (Pc) complexes (5-12) containing Zn, Ga, In central metals and substituted with benzyloxyphenoxy, phenoxy, tertbutylphenoxy and amino groups in solution and in poly (methyl methacrylate) (PMMA) films. The optical limiting parameters of Pcs were higher for tertbutylphenoxy when compared to benzyloxyphenoxy and phenoxy substituents, in DMSO. Non-peripheral substitution decreased the optical limiting parameters. Third-order susceptibility (Im[χ⁽³⁾]/α) values of Pcs in the absence and presence of CdTe QDs were in the 10⁻¹² to 10⁻¹° esu cm range. Hyperpolarizabilities (γ) ranged from 10⁻³¹ to 10⁻²⁹ esu L for Pc alone or in mixture with QDs. The effect on the optical limiting abilities of twelve embedded phthalocyanines containing In, Ga, Zn and Al as central metals in polymer thin films was also examined. The effect of forming a covalent link zinc tetraamino phthalocyanine (12) with poly (methyl acrylic acid) (PMAA) and Zn (13) and OHAl (14) octacarboxy phthalocyanines to polyethylenimine (PEI) was also studied. The hyperpolarizability of the twelve phthalocyanines in polymer was found to be in the range of 10⁻²⁶ to 10⁻²⁴ esu.L. This is significantly higher than the hyperpolarizabilities of these phthalocyanines in solution. Non-linear optical (NLO) parameters were determined for phthalocyanine complexes containing In, Ga and Zn as central metals when embedded in PMMA polymer in the presence of quantum dots (QDs). The QDs mainly employed were CdTe-TGA (TGA = thioglylcolic acid). Triplet lifetimes increased as k (excited state (σex) to ground state (σg) absorption cross section ratio) values decreased with the addition of the CdTe-TGA to the phthalocyanines. The saturation energy density (Fsat) values were smaller in the films when compared to the solutions. Complex 7 tetrasubstituted with tert-butylphenoxy groups at non-peripheral positions was also studied in the presence of CdS-TGA, CdSe-TGA, fullerenes and single walled carbon nanotubes. There is a general improvement in optical limiting ability of Pc complexes in the presence of nanomaterials (NMs). Degradation studies seem to indicate that placing a phthalocyanine within a polymer thin film may protect it slightly from photo- and thermal degradation. 3(4), 15(16)-Bis-(4 -tert-butyl-phenoxy)-10, 22-diaminohemiporphyrazinato chloroindium hemiporphyrazine was synthesized from 1, 3, 5-triaminobenzene and 4-tert-butyl-phenoxyisoindoline. The structure of the complex was confirmed using mass, nuclear magnetic resonance and infrared spectroscopies. The nonlinear parameters of the compound was also analyzed in dimethylformamide and found to be significantly greater than previously analyzed phthalocyanines.
- Full Text:
- Date Issued: 2014
- Authors: Britton, Jonathan
- Date: 2014
- Subjects: Phthalocyanines Photochemistry Nanoparticles Nanostructured materials Polymers Quantum dots
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4464 , http://hdl.handle.net/10962/d1011608
- Description: This thesis presents the study of the effects of CdTe-TGA quantum dots (QDs) on optical limiting ability of different phthalocyanine (Pc) complexes (5-12) containing Zn, Ga, In central metals and substituted with benzyloxyphenoxy, phenoxy, tertbutylphenoxy and amino groups in solution and in poly (methyl methacrylate) (PMMA) films. The optical limiting parameters of Pcs were higher for tertbutylphenoxy when compared to benzyloxyphenoxy and phenoxy substituents, in DMSO. Non-peripheral substitution decreased the optical limiting parameters. Third-order susceptibility (Im[χ⁽³⁾]/α) values of Pcs in the absence and presence of CdTe QDs were in the 10⁻¹² to 10⁻¹° esu cm range. Hyperpolarizabilities (γ) ranged from 10⁻³¹ to 10⁻²⁹ esu L for Pc alone or in mixture with QDs. The effect on the optical limiting abilities of twelve embedded phthalocyanines containing In, Ga, Zn and Al as central metals in polymer thin films was also examined. The effect of forming a covalent link zinc tetraamino phthalocyanine (12) with poly (methyl acrylic acid) (PMAA) and Zn (13) and OHAl (14) octacarboxy phthalocyanines to polyethylenimine (PEI) was also studied. The hyperpolarizability of the twelve phthalocyanines in polymer was found to be in the range of 10⁻²⁶ to 10⁻²⁴ esu.L. This is significantly higher than the hyperpolarizabilities of these phthalocyanines in solution. Non-linear optical (NLO) parameters were determined for phthalocyanine complexes containing In, Ga and Zn as central metals when embedded in PMMA polymer in the presence of quantum dots (QDs). The QDs mainly employed were CdTe-TGA (TGA = thioglylcolic acid). Triplet lifetimes increased as k (excited state (σex) to ground state (σg) absorption cross section ratio) values decreased with the addition of the CdTe-TGA to the phthalocyanines. The saturation energy density (Fsat) values were smaller in the films when compared to the solutions. Complex 7 tetrasubstituted with tert-butylphenoxy groups at non-peripheral positions was also studied in the presence of CdS-TGA, CdSe-TGA, fullerenes and single walled carbon nanotubes. There is a general improvement in optical limiting ability of Pc complexes in the presence of nanomaterials (NMs). Degradation studies seem to indicate that placing a phthalocyanine within a polymer thin film may protect it slightly from photo- and thermal degradation. 3(4), 15(16)-Bis-(4 -tert-butyl-phenoxy)-10, 22-diaminohemiporphyrazinato chloroindium hemiporphyrazine was synthesized from 1, 3, 5-triaminobenzene and 4-tert-butyl-phenoxyisoindoline. The structure of the complex was confirmed using mass, nuclear magnetic resonance and infrared spectroscopies. The nonlinear parameters of the compound was also analyzed in dimethylformamide and found to be significantly greater than previously analyzed phthalocyanines.
- Full Text:
- Date Issued: 2014
The economic potential of small towns in the Eastern Cape Midlands
- Authors: Reynolds, Kian Andrew
- Date: 2009 , 2013-07-15
- Subjects: Small cities -- South Africa -- Eastern Cape Economic geography -- South Africa -- Eastern Cape Economic development -- South Africa -- Eastern Cape Rural development -- South Africa -- Eastern Cape Local government -- South Africa -- Eastern Cape Agriculture -- Economic aspects -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:1057 , http://hdl.handle.net/10962/d1007492
- Description: Small town economic decline has been experienced in many countries across the globe and can be explained through Geographical Economics, particularly the New Economic Geography, which suggests that agglomeration occurs as a natural outcome of high transportation and transactional costs. Yet despite the economic rationale behind their decline it is not an economic inevitability and there is evidence of towns in the United States, New Zealand and Canada that have reversed their economic fortunes. [n South Africa approximately 5 million people live in the 500 small towns and many more live in their rural hinterlands where povelty levels are extremely high within a national context. Within this context the thesis examines the current economic status and potential growth prospects of small towns in the Eastern Cape Midlands in South Africa in order to identify critical growth dri vers within small town economies. Five small towns were selected for the study via means of a purposive sample and were subjected to two regional modelling techniques, namely Shift-Share Analysis and Economic Base Theory to determine their current economic trends and past growth patterns, while a Social Accounting Matrix was utilised to identify important sectoral linkages, potential avenues for growth and evident leakages within small town economies. The sampled towns experienced negative economic growth trends between 1996 and 200 I, the primary loss in employment being accounted for by regional economic changes as opposed to national or industrial trends. The decline was more severely felt in primary/industrial sectors of the economy; evidence was found that manufacturing activities declined in all of the centres, despite the industry growing nationally. The Social Accounting Matrix highlighted strong links between the agricultural and services sectors within the national economy. Thus, considering that agriculture was identified as the primary economic driver within the region and the services sector the largest employer in all of the towns it is evident that the economic potential of the towns is to a certain extent linked to the success of agriculture in their hinterlands. Seven growth drivers, namely size, local economic development, existing markets, existing industries, infrastructure, municipal leadership and local entrepreneurs and were linked via means of a scoring framework to the sampled towns' economic potential. Whilst the results of actually determining a towns economic potential are not definitive the study does provide useful insights about the impact and potential role played by these drivers. Linked to this scoring framework and to Cook's (1971) hierarchy of places in the Eastern Cape Midlands four categories of towns were identified in the commercial falming areas and recommendations were made about appropriate developmental interventions at a municipal level, such as the need to retain local entrepreneurs and to invest in social amenities. Considering the evident need for development in rural areas the study provides critical insights into how to prioritise development strategies within small rural towns in commercial farming areas. In addition it would enable municipalities to critically reflect on their municipal Local Economic Development strategies and the relevance within the context of small towns. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2009
- Authors: Reynolds, Kian Andrew
- Date: 2009 , 2013-07-15
- Subjects: Small cities -- South Africa -- Eastern Cape Economic geography -- South Africa -- Eastern Cape Economic development -- South Africa -- Eastern Cape Rural development -- South Africa -- Eastern Cape Local government -- South Africa -- Eastern Cape Agriculture -- Economic aspects -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:1057 , http://hdl.handle.net/10962/d1007492
- Description: Small town economic decline has been experienced in many countries across the globe and can be explained through Geographical Economics, particularly the New Economic Geography, which suggests that agglomeration occurs as a natural outcome of high transportation and transactional costs. Yet despite the economic rationale behind their decline it is not an economic inevitability and there is evidence of towns in the United States, New Zealand and Canada that have reversed their economic fortunes. [n South Africa approximately 5 million people live in the 500 small towns and many more live in their rural hinterlands where povelty levels are extremely high within a national context. Within this context the thesis examines the current economic status and potential growth prospects of small towns in the Eastern Cape Midlands in South Africa in order to identify critical growth dri vers within small town economies. Five small towns were selected for the study via means of a purposive sample and were subjected to two regional modelling techniques, namely Shift-Share Analysis and Economic Base Theory to determine their current economic trends and past growth patterns, while a Social Accounting Matrix was utilised to identify important sectoral linkages, potential avenues for growth and evident leakages within small town economies. The sampled towns experienced negative economic growth trends between 1996 and 200 I, the primary loss in employment being accounted for by regional economic changes as opposed to national or industrial trends. The decline was more severely felt in primary/industrial sectors of the economy; evidence was found that manufacturing activities declined in all of the centres, despite the industry growing nationally. The Social Accounting Matrix highlighted strong links between the agricultural and services sectors within the national economy. Thus, considering that agriculture was identified as the primary economic driver within the region and the services sector the largest employer in all of the towns it is evident that the economic potential of the towns is to a certain extent linked to the success of agriculture in their hinterlands. Seven growth drivers, namely size, local economic development, existing markets, existing industries, infrastructure, municipal leadership and local entrepreneurs and were linked via means of a scoring framework to the sampled towns' economic potential. Whilst the results of actually determining a towns economic potential are not definitive the study does provide useful insights about the impact and potential role played by these drivers. Linked to this scoring framework and to Cook's (1971) hierarchy of places in the Eastern Cape Midlands four categories of towns were identified in the commercial falming areas and recommendations were made about appropriate developmental interventions at a municipal level, such as the need to retain local entrepreneurs and to invest in social amenities. Considering the evident need for development in rural areas the study provides critical insights into how to prioritise development strategies within small rural towns in commercial farming areas. In addition it would enable municipalities to critically reflect on their municipal Local Economic Development strategies and the relevance within the context of small towns. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2009