A systematic review and document analysis on the prevention of mother-to-child programmes to prevent vertical transmission of human immuno-deficiency virus
- Authors: Sobetwa, Nwabisa Nokuzola
- Date: 2017
- Subjects: AIDS (Disease) in pregnancy , Maternal health services , HIV infections -- Children -- Transmission -- Prevention
- Language: English
- Type: Thesis , Masters , MSoc
- Identifier: http://hdl.handle.net/10353/7957 , vital:31282
- Description: Background: The National Strategic Plan 2012-2016 is advocating for zero new infections due to vertical transmission. This goal has not yet been achieved. This study evaluated whether the prevention of mother-to-child vertical transmission (PMTCT) of Human Immuno-deficiency Virus (HIV) programmes in South Africa are based on evidence. Aim: The aim of this study was to conduct a systematic review of the available literature comparing PMTCT antiretroviral regimens published between the years 2000 to 2015 and to do a document analysis of the current implemented PMTCT programme to evaluate if it is based on best evidence. Rational: The rational of the systematic review and the document analysis were to assess whether the latest PMTCT policy was based on evidence and to critically analyse published articles that addressed aspects related to efficacy and efficiency of PMTCT programmes to reduce transmission of HIV from mothers to their infants. Methods: Overall 25 randomised controlled trials and primary studies that assessed efficacy of ARV regimens to prevent mother-to-child transmission of the HIV during pregnancy, labour and the postnatal periods were systematically reviewed. In 1997 the first trial began and the last one ended in 2012. Twelve guidelines referring to PMTCT were sampled and they were published by WHO and Department of Health South Africa from 2001 to 2015. The document analysis was only based on National consolidated guidelines for the prevention of mother-to-child transmission of HIV (PMTCT) and the management of HIV in children, adolescents and adults April, 2015. Findings: The systematic review illustrated that significantly fewer infants tested HIV-positive when exposed to a longer ARV regime although there was no significant difference once the infants reached six months of age. Different ARVs have a similar Preamble effect on maternal deaths; however, a double or triple combination of ARVs is superior to monotherapy to decrease infant deaths. Common maternal adverse reactions to ARVs include anaemia, bronchopneumonia, and maculopapular rash. Infant adverse events included septicaemia, pneumonia, gastroenteritis, fever and maculopapular rash. The document analysis has shown that the PMTCT policy is mainly based on evidence from randomised controlled trials and systematic reviews. Occasionally some statements are still based on lower categories of evidence such as non-experimental descriptive studies. Conclusion: The systematic review showed that double and triple ARV therapy is superior to monotherapy and that the longer the mother and her infant are exposed to ARV therapy the better the results are to prevent MTCT. Adverse events are always posing a challenge and as with any other medication, caregivers must be aware of potential adverse reactions. The National consolidated guidelines for the prevention of mother-to-child transmission of HIV (PMTCT) and the management of HIV in children, adolescents and adults April 2015 is based on evidence, but the policy itself does not include any reference to evidence.
- Full Text:
- Date Issued: 2017
- Authors: Sobetwa, Nwabisa Nokuzola
- Date: 2017
- Subjects: AIDS (Disease) in pregnancy , Maternal health services , HIV infections -- Children -- Transmission -- Prevention
- Language: English
- Type: Thesis , Masters , MSoc
- Identifier: http://hdl.handle.net/10353/7957 , vital:31282
- Description: Background: The National Strategic Plan 2012-2016 is advocating for zero new infections due to vertical transmission. This goal has not yet been achieved. This study evaluated whether the prevention of mother-to-child vertical transmission (PMTCT) of Human Immuno-deficiency Virus (HIV) programmes in South Africa are based on evidence. Aim: The aim of this study was to conduct a systematic review of the available literature comparing PMTCT antiretroviral regimens published between the years 2000 to 2015 and to do a document analysis of the current implemented PMTCT programme to evaluate if it is based on best evidence. Rational: The rational of the systematic review and the document analysis were to assess whether the latest PMTCT policy was based on evidence and to critically analyse published articles that addressed aspects related to efficacy and efficiency of PMTCT programmes to reduce transmission of HIV from mothers to their infants. Methods: Overall 25 randomised controlled trials and primary studies that assessed efficacy of ARV regimens to prevent mother-to-child transmission of the HIV during pregnancy, labour and the postnatal periods were systematically reviewed. In 1997 the first trial began and the last one ended in 2012. Twelve guidelines referring to PMTCT were sampled and they were published by WHO and Department of Health South Africa from 2001 to 2015. The document analysis was only based on National consolidated guidelines for the prevention of mother-to-child transmission of HIV (PMTCT) and the management of HIV in children, adolescents and adults April, 2015. Findings: The systematic review illustrated that significantly fewer infants tested HIV-positive when exposed to a longer ARV regime although there was no significant difference once the infants reached six months of age. Different ARVs have a similar Preamble effect on maternal deaths; however, a double or triple combination of ARVs is superior to monotherapy to decrease infant deaths. Common maternal adverse reactions to ARVs include anaemia, bronchopneumonia, and maculopapular rash. Infant adverse events included septicaemia, pneumonia, gastroenteritis, fever and maculopapular rash. The document analysis has shown that the PMTCT policy is mainly based on evidence from randomised controlled trials and systematic reviews. Occasionally some statements are still based on lower categories of evidence such as non-experimental descriptive studies. Conclusion: The systematic review showed that double and triple ARV therapy is superior to monotherapy and that the longer the mother and her infant are exposed to ARV therapy the better the results are to prevent MTCT. Adverse events are always posing a challenge and as with any other medication, caregivers must be aware of potential adverse reactions. The National consolidated guidelines for the prevention of mother-to-child transmission of HIV (PMTCT) and the management of HIV in children, adolescents and adults April 2015 is based on evidence, but the policy itself does not include any reference to evidence.
- Full Text:
- Date Issued: 2017
Copycat
- Authors: Thomas, Adèle
- Date: 2014
- Subjects: Creative writing (Higher education) -- Research -- South Africa , Creative writing -- Fiction , South African fiction (English) -- Study and teaching (Higher) , South African fiction (English) -- 21st century
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5975 , http://hdl.handle.net/10962/d1012984
- Description: An exchange programme involving students and academics from Egoli University in Johannesburg and the University of Athens provides the conduit for the smuggling of Venetian Grossi coins discovered on the Cycladic island of Naxos. Thirty-five year old Delancey James, a Professor of Ethics at Egoli University, stumbles upon events associated with the murder of a post-graduate student. Through her investigation, she uncovers a web of intrigue that links the coin smuggling to corruption at the highest levels of the University, and, in the process, her life is placed in mortal danger.
- Full Text:
- Date Issued: 2014
- Authors: Thomas, Adèle
- Date: 2014
- Subjects: Creative writing (Higher education) -- Research -- South Africa , Creative writing -- Fiction , South African fiction (English) -- Study and teaching (Higher) , South African fiction (English) -- 21st century
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5975 , http://hdl.handle.net/10962/d1012984
- Description: An exchange programme involving students and academics from Egoli University in Johannesburg and the University of Athens provides the conduit for the smuggling of Venetian Grossi coins discovered on the Cycladic island of Naxos. Thirty-five year old Delancey James, a Professor of Ethics at Egoli University, stumbles upon events associated with the murder of a post-graduate student. Through her investigation, she uncovers a web of intrigue that links the coin smuggling to corruption at the highest levels of the University, and, in the process, her life is placed in mortal danger.
- Full Text:
- Date Issued: 2014
Enhancing learner centred education through the eco-schools framework: case studies of eco-schools practice in South Africa and Namibia
- Authors: Haingura, Rudolph
- Date: 2009
- Subjects: Education -- South Africa -- Case studies Education -- Namibia -- Case studies Educational change -- South Africa -- Case studies Educational change -- Namibia -- Case studies Teachers -- Training of -- South Africa -- Case studies Teachers -- Training of -- Namibia -- Case studies Environmental education -- South Africa -- Case studies Environmental education -- Namibia -- Case studies School improvement programs
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1509 , http://hdl.handle.net/10962/d1003391
- Description: Since the early 1990’s both South Africa and Namibia have been engaged in educational reform processes to address the discriminatory impacts and orientations of education under Bantu Education which were implemented in both countries prior to independence (Namibia in 1990, and South Africa in 1994). A feature of both educational reform processes is the underpinning theory of learning which draws on social constructivism, and which is articulated as learner centred education. This approach to teaching and learning infuses both policy frameworks. Another common feature is the introduction of environmental education into the formal education systems of both countries, a process which has been championed by development assistance, and which has been supported by programmes such as the Eco-Schools programme which is an international environmental education initiative started after the Rio Earth Summit in 1992, and implemented in a number of countries, including South Africa. The programme has also been piloted in some schools in Namibia. To date no research has been done on the way in which the Eco-Schools framework (its practices, organizing principles, evaluation processes etc.) enhance learner centred education. This study therefore aimed to investigate and understand how the Eco-Schools framework can enhance learner centred education. The study was conducted in 2007 in three Eco-Schools in Namibia and four Eco-Schools in South Africa in the context of the broader national programmes of implementing learner centred education policies, and environmental education histories. The study used a case study methodology, using observation, interviews, and document analysis as the main methods for data generation. The analytical process followed two stages: the first involved an inductive analysis using categories which were organized into a series of analytical memos. The second phase of data analysis involved recontextualising the data drawing on theory and contextual insights to provide insights that address the research question, using analytical statements. The main findings of the study are that the Eco-Schools framework provides numerous opportunities to enhance learner centred education, through contextualization of learning, through strengthening school-community interactions, and through enabling active involvement of learners in decision making and a range of contextually meaningful Eco-Schools practices. The study also showed that the Eco-Schools framework allows for empowerment of learners in relation to diverse needs, and also allows for learner initiated contributions, although this aspect was not well developed in the schools that were included in this study. The study also found that the benefits of Eco-Schools in terms of enhancing learner centred education were limited to only a few learners who were involved in club activities or who were being taught by enthusiastic teachers who were participating in the Eco-Schools programme. The study showed that these benefits can be more widely shared if more teachers were to get involved, and if the Eco-Schools programme were better understood in relation to the curriculum requirements of various subjects and learning areas, and if the Eco-Schools practices could be more successfully integrated across the curriculum. The study also showed that various forms of support were required for implementing the Eco-Schools programme, most notably the support of the Principal, and the Department of Education. The study also identified that parents and other stakeholders in the school were supportive of the Eco-Schools programme since it was perceived to have relevance to learning, as well as the community. The results broadly confirmed that the implementation of Eco-Schools using a whole school, values based and active learning approach promotes a school culture which enhances learner centred education more broadly across the school. The study also found that the Eco-Schools programme added a new dimension to existing discourses on learner centred education, which could be described as a community linked or situated approach to learner centred education.
- Full Text:
- Date Issued: 2009
- Authors: Haingura, Rudolph
- Date: 2009
- Subjects: Education -- South Africa -- Case studies Education -- Namibia -- Case studies Educational change -- South Africa -- Case studies Educational change -- Namibia -- Case studies Teachers -- Training of -- South Africa -- Case studies Teachers -- Training of -- Namibia -- Case studies Environmental education -- South Africa -- Case studies Environmental education -- Namibia -- Case studies School improvement programs
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1509 , http://hdl.handle.net/10962/d1003391
- Description: Since the early 1990’s both South Africa and Namibia have been engaged in educational reform processes to address the discriminatory impacts and orientations of education under Bantu Education which were implemented in both countries prior to independence (Namibia in 1990, and South Africa in 1994). A feature of both educational reform processes is the underpinning theory of learning which draws on social constructivism, and which is articulated as learner centred education. This approach to teaching and learning infuses both policy frameworks. Another common feature is the introduction of environmental education into the formal education systems of both countries, a process which has been championed by development assistance, and which has been supported by programmes such as the Eco-Schools programme which is an international environmental education initiative started after the Rio Earth Summit in 1992, and implemented in a number of countries, including South Africa. The programme has also been piloted in some schools in Namibia. To date no research has been done on the way in which the Eco-Schools framework (its practices, organizing principles, evaluation processes etc.) enhance learner centred education. This study therefore aimed to investigate and understand how the Eco-Schools framework can enhance learner centred education. The study was conducted in 2007 in three Eco-Schools in Namibia and four Eco-Schools in South Africa in the context of the broader national programmes of implementing learner centred education policies, and environmental education histories. The study used a case study methodology, using observation, interviews, and document analysis as the main methods for data generation. The analytical process followed two stages: the first involved an inductive analysis using categories which were organized into a series of analytical memos. The second phase of data analysis involved recontextualising the data drawing on theory and contextual insights to provide insights that address the research question, using analytical statements. The main findings of the study are that the Eco-Schools framework provides numerous opportunities to enhance learner centred education, through contextualization of learning, through strengthening school-community interactions, and through enabling active involvement of learners in decision making and a range of contextually meaningful Eco-Schools practices. The study also showed that the Eco-Schools framework allows for empowerment of learners in relation to diverse needs, and also allows for learner initiated contributions, although this aspect was not well developed in the schools that were included in this study. The study also found that the benefits of Eco-Schools in terms of enhancing learner centred education were limited to only a few learners who were involved in club activities or who were being taught by enthusiastic teachers who were participating in the Eco-Schools programme. The study showed that these benefits can be more widely shared if more teachers were to get involved, and if the Eco-Schools programme were better understood in relation to the curriculum requirements of various subjects and learning areas, and if the Eco-Schools practices could be more successfully integrated across the curriculum. The study also showed that various forms of support were required for implementing the Eco-Schools programme, most notably the support of the Principal, and the Department of Education. The study also identified that parents and other stakeholders in the school were supportive of the Eco-Schools programme since it was perceived to have relevance to learning, as well as the community. The results broadly confirmed that the implementation of Eco-Schools using a whole school, values based and active learning approach promotes a school culture which enhances learner centred education more broadly across the school. The study also found that the Eco-Schools programme added a new dimension to existing discourses on learner centred education, which could be described as a community linked or situated approach to learner centred education.
- Full Text:
- Date Issued: 2009
Social learning processes of HIV/AIDS women caregivers on their use of traditional foods and medicinal plants : the case of Raphael Centre and Keiskamma Art and Health Centre communities of practice, Eastern Cape Province, South Africa
- Authors: Shonhai, Venencia F
- Date: 2009
- Subjects: Keiskamma Art Project (South Africa) , Women caregivers -- South Africa -- Eastern Cape , HIV infections -- Study and teaching -- South Africa , AIDS (Disease) -- Study and teaching -- South Africa , HIV-positive persons -- Care -- South Africa -- Eastern Cape , Medicinal plants -- South Africa , Natural foods -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1768 , http://hdl.handle.net/10962/d1003653
- Description: The scale of people being infected by HIV/AIDS (Human Immunodeficiency Virus /Acquired Immune Deficiency Syndrome) has meant that the family and the community have had to become involved in caring for the sick (Van Dyk, 2005). This has inevitably led to the emergence of informal caregivers in the form of family members caring for their relatives (Kipp, Nkosi, Laing & Jhangri, 2006). The research investigated the social learning of women caregivers looking after people living with HIV/AIDS, with emphasis on caregiving practices related to how they use traditional foods and medicinal plants. The research was undertaken in Grahamstown at the Raphael Centre and in Hamburg at Keiskkamma Health Centre and Art Project, Eastern Cape, South Africa. Data was collected using interviews, focus group discussions and diaries written by participants. The data was analyzed in two phases: the first phase involved reading the interview transcripts and collating the responses into analytical memos that were captured into broad categories, while the second phase made use of the community of practice analytical framework to further analyze the data to get better understanding of the social learning processes. This study reveals that participating in a community of practice like Raphael Centre and Keiskamma Health Centre enables caregivers to learn about caregiving. It also reveals that within these communities of practice there are varied learning processes that take place, such as observational and collaborative learning. The research also revealed that caregivers learn from the communities from which they come, for example caregivers learn about traditional food and medicinal plants which they use from their family members, friends, other caregivers as well as non governmental organizations. The research found that caregivers are influenced in their learning and practices by a number of factors which include their own experiences, ambivalent messages from different stakeholders concerned with fighting HIV/AIDS and exposure to new information. The research recommends that diverse learning processes in a community of practice and outside a community of practice should be encouraged and strengthened. It also recommends that HIV/AIDS caregiving options should be strengthened by drawing on experience and knowledge of caregivers. Caregivers should be encouraged to be selfsustaining to improve their caregiving practices. Stakeholders in the field of HIV/AIDS should be alert to and address ambivalence on use of medicinal plants. Existing programmes that enable women to learn about new information on HIV/AIDS should be strengthened.
- Full Text:
- Date Issued: 2009
- Authors: Shonhai, Venencia F
- Date: 2009
- Subjects: Keiskamma Art Project (South Africa) , Women caregivers -- South Africa -- Eastern Cape , HIV infections -- Study and teaching -- South Africa , AIDS (Disease) -- Study and teaching -- South Africa , HIV-positive persons -- Care -- South Africa -- Eastern Cape , Medicinal plants -- South Africa , Natural foods -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1768 , http://hdl.handle.net/10962/d1003653
- Description: The scale of people being infected by HIV/AIDS (Human Immunodeficiency Virus /Acquired Immune Deficiency Syndrome) has meant that the family and the community have had to become involved in caring for the sick (Van Dyk, 2005). This has inevitably led to the emergence of informal caregivers in the form of family members caring for their relatives (Kipp, Nkosi, Laing & Jhangri, 2006). The research investigated the social learning of women caregivers looking after people living with HIV/AIDS, with emphasis on caregiving practices related to how they use traditional foods and medicinal plants. The research was undertaken in Grahamstown at the Raphael Centre and in Hamburg at Keiskkamma Health Centre and Art Project, Eastern Cape, South Africa. Data was collected using interviews, focus group discussions and diaries written by participants. The data was analyzed in two phases: the first phase involved reading the interview transcripts and collating the responses into analytical memos that were captured into broad categories, while the second phase made use of the community of practice analytical framework to further analyze the data to get better understanding of the social learning processes. This study reveals that participating in a community of practice like Raphael Centre and Keiskamma Health Centre enables caregivers to learn about caregiving. It also reveals that within these communities of practice there are varied learning processes that take place, such as observational and collaborative learning. The research also revealed that caregivers learn from the communities from which they come, for example caregivers learn about traditional food and medicinal plants which they use from their family members, friends, other caregivers as well as non governmental organizations. The research found that caregivers are influenced in their learning and practices by a number of factors which include their own experiences, ambivalent messages from different stakeholders concerned with fighting HIV/AIDS and exposure to new information. The research recommends that diverse learning processes in a community of practice and outside a community of practice should be encouraged and strengthened. It also recommends that HIV/AIDS caregiving options should be strengthened by drawing on experience and knowledge of caregivers. Caregivers should be encouraged to be selfsustaining to improve their caregiving practices. Stakeholders in the field of HIV/AIDS should be alert to and address ambivalence on use of medicinal plants. Existing programmes that enable women to learn about new information on HIV/AIDS should be strengthened.
- Full Text:
- Date Issued: 2009
The operation of letters of credit with particular reference to the doctrine of strict compliance, the principle of independence, the fraud exception and conflict of laws
- Makobe, Melanchton Phillip Malepe
- Authors: Makobe, Melanchton Phillip Malepe
- Date: 2001
- Subjects: Letters of credit Conflict of laws Fraud
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:3710 , http://hdl.handle.net/10962/d1007281
- Description: The thesis covers aspects of the law relating to letters of credit. It deals with the operation of letters of credit with particular reference to the doctrine of strict compliance, the principle of independence, the fraud exception and conflict of laws. According to the principle of independence, banks must make payment in terms of the letter of credit irrespective of any dispute that may exist between the buyer and the seller in an underlying contract or other contracts. Although the principle of independence is clearly established, it is not absolute. An exception occurs in the case of fraud. Thus, if the seller has committed fraud, such as tendering forged documents, the buyer can instruct the bank not to make payment in terms of the credit. If the bank refuses to dishonour the letter of credit, the buyer can apply to a court to interdict the bank from making payment. In South African law the buyer must establish that the seller was party to fraud in relation to the documents presented to the bank for payment before the court can grant an interdict. This thesis also examines the standard of proof of fraud required in letters of credit transactions and proposes a standard of proof which will not unduly favour the seller whose good faith is in dispute. The fast growing technology of computers and telecommunications is rapidly changing the methods of transacting business by paper documentation and letter of credit transactions are no exception. At present the buyer can apply to the bank to issue a letter of credit through the computer and banks also communicate letter of credit transactions through computer networks. However, the beneficiary still has to present documents to the bank for payment in paper form. It is proposed that the Uniform Custom and Practice For Documentary Credits (UCP) be amended to provide for fully computerised letters of credit transactions. Another objective of the thesis is to examine the doctrine of strict compliance. In terms of the doctrine of strict compliance documents presented under the credit must comply strictly with the requirements set out in the credit. If banks are satisfied that the documents presented by the seller strictly conform with the requirements of the credit they are obliged to make payment as required by the credit. It is proposed that the doctrine of strict compliance should not be applied strictly. In other words, the banks should make payment in terms of the credit if the discrepancy in the documents is trivial. The thesis also covers conflict of laws issues. As the UCP does not have rules dealing with conflict of laws, most jurisdictions have developed their own rules to be applied by the courts in cases of conflict of laws. The thesis examines the different rules of conflict of laws as developed and practiced by different jurisdictions.
- Full Text:
- Date Issued: 2001
- Authors: Makobe, Melanchton Phillip Malepe
- Date: 2001
- Subjects: Letters of credit Conflict of laws Fraud
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:3710 , http://hdl.handle.net/10962/d1007281
- Description: The thesis covers aspects of the law relating to letters of credit. It deals with the operation of letters of credit with particular reference to the doctrine of strict compliance, the principle of independence, the fraud exception and conflict of laws. According to the principle of independence, banks must make payment in terms of the letter of credit irrespective of any dispute that may exist between the buyer and the seller in an underlying contract or other contracts. Although the principle of independence is clearly established, it is not absolute. An exception occurs in the case of fraud. Thus, if the seller has committed fraud, such as tendering forged documents, the buyer can instruct the bank not to make payment in terms of the credit. If the bank refuses to dishonour the letter of credit, the buyer can apply to a court to interdict the bank from making payment. In South African law the buyer must establish that the seller was party to fraud in relation to the documents presented to the bank for payment before the court can grant an interdict. This thesis also examines the standard of proof of fraud required in letters of credit transactions and proposes a standard of proof which will not unduly favour the seller whose good faith is in dispute. The fast growing technology of computers and telecommunications is rapidly changing the methods of transacting business by paper documentation and letter of credit transactions are no exception. At present the buyer can apply to the bank to issue a letter of credit through the computer and banks also communicate letter of credit transactions through computer networks. However, the beneficiary still has to present documents to the bank for payment in paper form. It is proposed that the Uniform Custom and Practice For Documentary Credits (UCP) be amended to provide for fully computerised letters of credit transactions. Another objective of the thesis is to examine the doctrine of strict compliance. In terms of the doctrine of strict compliance documents presented under the credit must comply strictly with the requirements set out in the credit. If banks are satisfied that the documents presented by the seller strictly conform with the requirements of the credit they are obliged to make payment as required by the credit. It is proposed that the doctrine of strict compliance should not be applied strictly. In other words, the banks should make payment in terms of the credit if the discrepancy in the documents is trivial. The thesis also covers conflict of laws issues. As the UCP does not have rules dealing with conflict of laws, most jurisdictions have developed their own rules to be applied by the courts in cases of conflict of laws. The thesis examines the different rules of conflict of laws as developed and practiced by different jurisdictions.
- Full Text:
- Date Issued: 2001
Reduction of tungsten oxides with carbon and hydrogen
- Authors: Venables, Dean Stuart
- Date: 1996
- Subjects: Oxidation-reduction reaction , Tungsten , Hydrogen , Carbon
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4342 , http://hdl.handle.net/10962/d1005004 , Oxidation-reduction reaction , Tungsten , Hydrogen , Carbon
- Description: The reductions of WO₃ with hydrogen, with CO, and with carbon, as well as the reduction of WO₃/graphite mixtures with hydrogen, were studied using thermogravimetry, evolved gas analysis, X-ray powder diffraction, and scanning electron microscopy. The intermediate phases W₂₀O₅₈, W₁₈O₄₉ and WO₂, were observed in the reductions. The final product of the reductions with hydrogen and carbon was tungsten, and we was formed in the reduction with CO. The reaction paths in the overall processes were determined. The reactant/product gas ratio had a considerable influence on which reactions took place. The morphology of the sample was characterised at different stages of the reduction. The shape of the WO₃ particles was retained during the reduction. Particle growth was observed in the reduction with hydrogen and was attributed to the formation of WO₂(OH)₂(g). The kinetics of the reductions were investigated , and the reaction mechanisms determined. The reduction of WO₃ with CO was studied from 650 to 900°C, and occurred at a phase boundary with an activation energy of 40 kJ mol⁻¹ . The reduction of WO₂, was studied under the same conditions. The reaction also occurred at a phase boundary and had an activation energy of 62 kJ mol⁻¹. The reduction of WO₃ with carbon was studied from 935 to 1100°C and took place via CO and CO₂. Two stages were observed in the reduction . The first stage, which corresponded approximately to the formation of WO₂ had an activation energy of 66 kJ mol⁻¹ and was limited by diffusion through the porous reacting particles. The second stage was first order and had an activation energy of 40 kJ mol⁻¹. The reduction of WO₃ and WO₃ graphite mixtures with hydrogen were studied from 575 to 975 °C. The reactions were controlled by mass-transfer under the conditions investigated. The addition of carbon increased the rate of the reduction process , but did not affect the phases formed in the system. CO₂ was evolved mainly at the start, and CO mainly at the end of the process.
- Full Text:
- Date Issued: 1996
- Authors: Venables, Dean Stuart
- Date: 1996
- Subjects: Oxidation-reduction reaction , Tungsten , Hydrogen , Carbon
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4342 , http://hdl.handle.net/10962/d1005004 , Oxidation-reduction reaction , Tungsten , Hydrogen , Carbon
- Description: The reductions of WO₃ with hydrogen, with CO, and with carbon, as well as the reduction of WO₃/graphite mixtures with hydrogen, were studied using thermogravimetry, evolved gas analysis, X-ray powder diffraction, and scanning electron microscopy. The intermediate phases W₂₀O₅₈, W₁₈O₄₉ and WO₂, were observed in the reductions. The final product of the reductions with hydrogen and carbon was tungsten, and we was formed in the reduction with CO. The reaction paths in the overall processes were determined. The reactant/product gas ratio had a considerable influence on which reactions took place. The morphology of the sample was characterised at different stages of the reduction. The shape of the WO₃ particles was retained during the reduction. Particle growth was observed in the reduction with hydrogen and was attributed to the formation of WO₂(OH)₂(g). The kinetics of the reductions were investigated , and the reaction mechanisms determined. The reduction of WO₃ with CO was studied from 650 to 900°C, and occurred at a phase boundary with an activation energy of 40 kJ mol⁻¹ . The reduction of WO₂, was studied under the same conditions. The reaction also occurred at a phase boundary and had an activation energy of 62 kJ mol⁻¹. The reduction of WO₃ with carbon was studied from 935 to 1100°C and took place via CO and CO₂. Two stages were observed in the reduction . The first stage, which corresponded approximately to the formation of WO₂ had an activation energy of 66 kJ mol⁻¹ and was limited by diffusion through the porous reacting particles. The second stage was first order and had an activation energy of 40 kJ mol⁻¹. The reduction of WO₃ and WO₃ graphite mixtures with hydrogen were studied from 575 to 975 °C. The reactions were controlled by mass-transfer under the conditions investigated. The addition of carbon increased the rate of the reduction process , but did not affect the phases formed in the system. CO₂ was evolved mainly at the start, and CO mainly at the end of the process.
- Full Text:
- Date Issued: 1996
An investigation into the relationship between kinesthetic sensitivity and balancing ability in pre-school children
- Authors: Burger, Laetitia Mary
- Date: 1991
- Subjects: Motor ability in children Perception in children Preschool children
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1615 , http://hdl.handle.net/10962/d1003497
- Description: The purpose of this study was to explore the possibility of a linear relationship between kinesthetic sensitivity and balancing ability in pre-school children. Furthermore, the effects of age on kinesthetic sensitivity and balancing ability were investigated. Finally, the role of gender in kinesthetic sensitivity and balancing ability was examined. Fifty-one subjects, between the ages of three and six years, executed five trials on each of two kinesthetic sensitivity tests (an arm abduction test and a hip abduction test); two tests for static balance (on a balance board and on a balance stick) and two tests for dynamic balance (a beam walk test and a stepping stones test). Although the correlations between kinesthetic sensitivity and balancing ability were generally positive, they were very slight. These low correlations are probably an indication that different abilities are required for carrying out the different tasks. Generally, both balancing ability and kinesthetic sensitivity appeared to improve with age. From analysis of individual test results it was obvious that abilities varied from individual to individual (Appendix G). This could have been the result of developmental, motivational or experiential differences. Although the girls generally performed slightly better on most tests than the boys the correlations between test scores for boys were slightly higher than those for girls. At-test indicated that there were no significant differences between the mean scores of the boys and the girls on the balancing or the kinesthetic sensitivity tasks.
- Full Text:
- Date Issued: 1991
- Authors: Burger, Laetitia Mary
- Date: 1991
- Subjects: Motor ability in children Perception in children Preschool children
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1615 , http://hdl.handle.net/10962/d1003497
- Description: The purpose of this study was to explore the possibility of a linear relationship between kinesthetic sensitivity and balancing ability in pre-school children. Furthermore, the effects of age on kinesthetic sensitivity and balancing ability were investigated. Finally, the role of gender in kinesthetic sensitivity and balancing ability was examined. Fifty-one subjects, between the ages of three and six years, executed five trials on each of two kinesthetic sensitivity tests (an arm abduction test and a hip abduction test); two tests for static balance (on a balance board and on a balance stick) and two tests for dynamic balance (a beam walk test and a stepping stones test). Although the correlations between kinesthetic sensitivity and balancing ability were generally positive, they were very slight. These low correlations are probably an indication that different abilities are required for carrying out the different tasks. Generally, both balancing ability and kinesthetic sensitivity appeared to improve with age. From analysis of individual test results it was obvious that abilities varied from individual to individual (Appendix G). This could have been the result of developmental, motivational or experiential differences. Although the girls generally performed slightly better on most tests than the boys the correlations between test scores for boys were slightly higher than those for girls. At-test indicated that there were no significant differences between the mean scores of the boys and the girls on the balancing or the kinesthetic sensitivity tasks.
- Full Text:
- Date Issued: 1991
'n Marxisties-feministiese ondersoek van Wilma Stockenström se roman, Die kremetartekspedisie
- Authors: Gardner, Judy Hilary
- Date: 1989
- Subjects: Stockenström, Wilma -- Criticism and interpretation , Stockenström, Wilma. Kremetartekspedisie
- Language: Afrikaans
- Type: text , Thesis , Masters , MA
- Identifier: vital:3568 , http://hdl.handle.net/10962/d1002091
- Description: Chapter is an exploration of the meanings which may underly the title of this novel. I have tried initially to establish what kind of "expedition" is undertaken, and have come to the conclusion that "expedition" has a multidimensional meaning, that it implies a search, an expedition into different things: an expedition to the city of rose-quartz; the slave woman's expeditions from the baobab tree and back; an inner expedition to gain self-knowledge; an expedition into womanhood; an expedition into the history of Africa, into religion, into language. The second part of the chapter examines the nature of "baobab", since this tree, like the "Tree of Life", is regarded as one growing upside-down. It is this upside-down nature of the tree which led me to believe that many existing stereotypes and myths are turned upside-down in the novel: about slaves, about woman, language, the Afrikaans literary tradition, the "traditional" structure of the novel, culture transcending nature, the slave woman's language. In chapter 2 I have examined only one of these expeditions, viz. the slave woman's inner expeditions consisting of her experiences as a slave and her journeys of reminiscence. These journeys at the same time embrace all the other expeditions. Her inner expeditions are signified by a number of codes, which fulfil literally the function of processes of knowledge, of self- knowledge, as well as of systems in which meaning is contained. By undertaking this inner expedition, the woman gains greater clarity of vision concerning her own existence and the existence of man/woman in general. Chapter 3 deals mainly with the concept of possession/ownership, which results in two diametrically opposed groups: the owner class and the owned class. The peculiar institution of slavery has given rise to these two irreconcilable groups, and therefore a brief history of slavery is included in this chapter. The slave woman is initially one of the owned class, but through indoctrination, she too aspires to become a member of the owner class. In the second half of the chapter, then, the woman is discussed as owner. Her position becomes a reflection of the position of her owners, to illustrate the peculiarity of the capitalist system in which there will always be the rulers and the subjects, the oppressor and the oppressed, the owner and the owned.
- Full Text:
- Date Issued: 1989
- Authors: Gardner, Judy Hilary
- Date: 1989
- Subjects: Stockenström, Wilma -- Criticism and interpretation , Stockenström, Wilma. Kremetartekspedisie
- Language: Afrikaans
- Type: text , Thesis , Masters , MA
- Identifier: vital:3568 , http://hdl.handle.net/10962/d1002091
- Description: Chapter is an exploration of the meanings which may underly the title of this novel. I have tried initially to establish what kind of "expedition" is undertaken, and have come to the conclusion that "expedition" has a multidimensional meaning, that it implies a search, an expedition into different things: an expedition to the city of rose-quartz; the slave woman's expeditions from the baobab tree and back; an inner expedition to gain self-knowledge; an expedition into womanhood; an expedition into the history of Africa, into religion, into language. The second part of the chapter examines the nature of "baobab", since this tree, like the "Tree of Life", is regarded as one growing upside-down. It is this upside-down nature of the tree which led me to believe that many existing stereotypes and myths are turned upside-down in the novel: about slaves, about woman, language, the Afrikaans literary tradition, the "traditional" structure of the novel, culture transcending nature, the slave woman's language. In chapter 2 I have examined only one of these expeditions, viz. the slave woman's inner expeditions consisting of her experiences as a slave and her journeys of reminiscence. These journeys at the same time embrace all the other expeditions. Her inner expeditions are signified by a number of codes, which fulfil literally the function of processes of knowledge, of self- knowledge, as well as of systems in which meaning is contained. By undertaking this inner expedition, the woman gains greater clarity of vision concerning her own existence and the existence of man/woman in general. Chapter 3 deals mainly with the concept of possession/ownership, which results in two diametrically opposed groups: the owner class and the owned class. The peculiar institution of slavery has given rise to these two irreconcilable groups, and therefore a brief history of slavery is included in this chapter. The slave woman is initially one of the owned class, but through indoctrination, she too aspires to become a member of the owner class. In the second half of the chapter, then, the woman is discussed as owner. Her position becomes a reflection of the position of her owners, to illustrate the peculiarity of the capitalist system in which there will always be the rulers and the subjects, the oppressor and the oppressed, the owner and the owned.
- Full Text:
- Date Issued: 1989
Investigation leading to a process for the synthesis of hydrogen sulphide from sulphur and certain lubricating oils derived from petroleum
- Authors: Schauder, H
- Date: 1952
- Subjects: Hydrogen sulfide
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4499 , http://hdl.handle.net/10962/d1013160
- Description: The primary object of the present study was to provide a process adaptable to prevailing South African conditions, for the manufacture of hydrogen sulphide. Such a process would also be suitable for use in other countries where the gas is not obtainable naturally or from refinery operations or as a by-product from other industries. Early in the study it was found that the literature embodying prior work was very scattered in character and had to be sought in many different fields of research. It was therefore decided to make the record of prior work as comprehensive as possible so as to provide, at the same time, a starting point tor future workers on related subjects. Intro., p. 1.
- Full Text:
- Date Issued: 1952
- Authors: Schauder, H
- Date: 1952
- Subjects: Hydrogen sulfide
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4499 , http://hdl.handle.net/10962/d1013160
- Description: The primary object of the present study was to provide a process adaptable to prevailing South African conditions, for the manufacture of hydrogen sulphide. Such a process would also be suitable for use in other countries where the gas is not obtainable naturally or from refinery operations or as a by-product from other industries. Early in the study it was found that the literature embodying prior work was very scattered in character and had to be sought in many different fields of research. It was therefore decided to make the record of prior work as comprehensive as possible so as to provide, at the same time, a starting point tor future workers on related subjects. Intro., p. 1.
- Full Text:
- Date Issued: 1952
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