Technological domination and the future of workers in the labour market in the face of automation: a study of the automobile sector in South Africa
- Authors: Chigbu, Bianca Ifeoma
- Date: 2020
- Subjects: Office practice -- Automation Employees -- Technological innovations Organizational change
- Language: English
- Type: Thesis , Doctoral , PhD(Sociology)
- Identifier: http://hdl.handle.net/10353/17954 , vital:41996
- Description: This exploratory work investigated the principal aim of this study: the rate of technological domination in South Africa and the future of workers in the labour market in the face of automation. It also explored collaborative experiences between technology and human workers and how employees in the automobile sector compete with technologies in their work environment. The future-readiness of workers in this automation age and union influence with regards to technology adoption in the world of work were also examined. The study utilized a qualitative research method with in-depth interviews of data collection with 30 respondents consisting of two managers and five auto plant workers from Mercedes Benz; two shop stewards from Toyota Motors; two union representatives and nineteen workers working in the auto plant in Volkswagen South Africa (VWSA). A desktop data collection process was also employed in this study. Evolutionary Economics Theory, Labour Process Theory and Corporate Social Responsibility drove the whole analysis to explain the technological outcome in the workplace. The central argument of this study is that robots and human employees must each efficiently interface where they can best be put to good use. However, in an attempt to minimise product imperfection due to human inconsistencies and to increase productivity, the automobile industry has adopted more technologies to meet the needs of its customers and remained competitive. Nonetheless, the rate at which the technologies are adopted has increased the rate of job automation in the automobile sector and has also led to the deskilling of the auto workforce. Additionally, technology is outcompeting human workers because it has changed and evolved more rapidly than workers. The study argues that despite that automation increases productivity, it is a threat to low skilled workers in the sense that workers might end up underemployed or unemployed although highly skilled workers might be further upskilled. The findings further revealed that the workers are not ready for this change. Another revelation is that there is a unilateral workplace restructuring decision making, which neglects the input of workers and their union with regards to how work should be restructured. The findings call for sustainable corporate responsible management. The largest adopter of industrial robots in manufacturing processes is the automobile sector since global competition in the labour market commands uninterrupted modernisation and automation of production processes in the automobile industry. Each production process is not imaginable without automation today. In the quest to transform the workplace, improve iv productivity, the economy and develop communities with technological adoption, it is imperative to consider the short and long-term sustainable socio-economic development for all. It is argued that almost all sectors and working classes are vulnerable to automation. KozulWright (2016) during the United Nation’s Conference on Trade and Development concurs with other scholars that job disruption from automation affect routine tasks and its negative impact is much in the developing countries. It was recommended that a professional qualification should be incorporated with an academic qualification that aligns with technical and non-technical unautomable skills. Transparency and accountability are a must on the part of all the stakeholders involved in the automobile industry, particularly from management, to make a more sustainable economic decision that will benefit the development of workers. It is equally important for organisations, policymakers, workers, union and societies to develop feasible strategies to manage added concerns of job automation such as polarisation in the societies, the workforce and which may create societal breakdowns and conflicts. At the same time, as these machines will evolve in decades to come, we should expect to see a drastic transformation in workforce development. This study contributes to satisfactory ways to facilitate job automation transition to counteract any negative outcome with reference to those workers who might be affected by the changes in order to achieve a better society.
- Full Text:
- Date Issued: 2020
- Authors: Chigbu, Bianca Ifeoma
- Date: 2020
- Subjects: Office practice -- Automation Employees -- Technological innovations Organizational change
- Language: English
- Type: Thesis , Doctoral , PhD(Sociology)
- Identifier: http://hdl.handle.net/10353/17954 , vital:41996
- Description: This exploratory work investigated the principal aim of this study: the rate of technological domination in South Africa and the future of workers in the labour market in the face of automation. It also explored collaborative experiences between technology and human workers and how employees in the automobile sector compete with technologies in their work environment. The future-readiness of workers in this automation age and union influence with regards to technology adoption in the world of work were also examined. The study utilized a qualitative research method with in-depth interviews of data collection with 30 respondents consisting of two managers and five auto plant workers from Mercedes Benz; two shop stewards from Toyota Motors; two union representatives and nineteen workers working in the auto plant in Volkswagen South Africa (VWSA). A desktop data collection process was also employed in this study. Evolutionary Economics Theory, Labour Process Theory and Corporate Social Responsibility drove the whole analysis to explain the technological outcome in the workplace. The central argument of this study is that robots and human employees must each efficiently interface where they can best be put to good use. However, in an attempt to minimise product imperfection due to human inconsistencies and to increase productivity, the automobile industry has adopted more technologies to meet the needs of its customers and remained competitive. Nonetheless, the rate at which the technologies are adopted has increased the rate of job automation in the automobile sector and has also led to the deskilling of the auto workforce. Additionally, technology is outcompeting human workers because it has changed and evolved more rapidly than workers. The study argues that despite that automation increases productivity, it is a threat to low skilled workers in the sense that workers might end up underemployed or unemployed although highly skilled workers might be further upskilled. The findings further revealed that the workers are not ready for this change. Another revelation is that there is a unilateral workplace restructuring decision making, which neglects the input of workers and their union with regards to how work should be restructured. The findings call for sustainable corporate responsible management. The largest adopter of industrial robots in manufacturing processes is the automobile sector since global competition in the labour market commands uninterrupted modernisation and automation of production processes in the automobile industry. Each production process is not imaginable without automation today. In the quest to transform the workplace, improve iv productivity, the economy and develop communities with technological adoption, it is imperative to consider the short and long-term sustainable socio-economic development for all. It is argued that almost all sectors and working classes are vulnerable to automation. KozulWright (2016) during the United Nation’s Conference on Trade and Development concurs with other scholars that job disruption from automation affect routine tasks and its negative impact is much in the developing countries. It was recommended that a professional qualification should be incorporated with an academic qualification that aligns with technical and non-technical unautomable skills. Transparency and accountability are a must on the part of all the stakeholders involved in the automobile industry, particularly from management, to make a more sustainable economic decision that will benefit the development of workers. It is equally important for organisations, policymakers, workers, union and societies to develop feasible strategies to manage added concerns of job automation such as polarisation in the societies, the workforce and which may create societal breakdowns and conflicts. At the same time, as these machines will evolve in decades to come, we should expect to see a drastic transformation in workforce development. This study contributes to satisfactory ways to facilitate job automation transition to counteract any negative outcome with reference to those workers who might be affected by the changes in order to achieve a better society.
- Full Text:
- Date Issued: 2020
Personality in relation to work-family conflict among employees in a mining company in South Africa
- Authors: Ruzungunde, Vongai Sarah
- Date: 2019
- Subjects: Job stress Role conflict Work and family
- Language: English
- Type: Thesis , Doctoral , PhD (Industrial Psychology)
- Identifier: http://hdl.handle.net/10353/17007 , vital:40809
- Description: The study set out to investigate how the Big Five personality traits related to work family conflict, taking into consideration the different forms of work family conflict within the mining industry. The study made use of the quantitative design, with the sample consisting of 270 respondents from the selected mine in South Africa. Probability sampling was used to select respondents from the whole population. Data was analysed using descriptive statistical analysis. To examine the association between variables, linear regression analysis was used. Confirmatory analysis was used to measure validity for work-family conflict (WFC). To measure the validity for personality; face validity, construct and content validity were used. Reliability was measured using the Cronbach alpha. The results of the study showed a significant negative relationship between the personality traits and WFC except for the agreeableness trait. The results also showed significant negative correlations with the different forms of WFC, except for the agreeableness trait. Further, the results showed that, when combined, personality traits had greater variance on the experiences of WFC than each of them separately. The findings of this study are helpful to the mining industry as they assist in the implementation of procedures and policies that will help to reduce WFC and its consequences in the work environment.
- Full Text:
- Date Issued: 2019
- Authors: Ruzungunde, Vongai Sarah
- Date: 2019
- Subjects: Job stress Role conflict Work and family
- Language: English
- Type: Thesis , Doctoral , PhD (Industrial Psychology)
- Identifier: http://hdl.handle.net/10353/17007 , vital:40809
- Description: The study set out to investigate how the Big Five personality traits related to work family conflict, taking into consideration the different forms of work family conflict within the mining industry. The study made use of the quantitative design, with the sample consisting of 270 respondents from the selected mine in South Africa. Probability sampling was used to select respondents from the whole population. Data was analysed using descriptive statistical analysis. To examine the association between variables, linear regression analysis was used. Confirmatory analysis was used to measure validity for work-family conflict (WFC). To measure the validity for personality; face validity, construct and content validity were used. Reliability was measured using the Cronbach alpha. The results of the study showed a significant negative relationship between the personality traits and WFC except for the agreeableness trait. The results also showed significant negative correlations with the different forms of WFC, except for the agreeableness trait. Further, the results showed that, when combined, personality traits had greater variance on the experiences of WFC than each of them separately. The findings of this study are helpful to the mining industry as they assist in the implementation of procedures and policies that will help to reduce WFC and its consequences in the work environment.
- Full Text:
- Date Issued: 2019
Parental involvement and grade 8 learners' academic achievement in mathematics : a study of selected schools in East London, South Africa
- Authors: Eesuola, Omobola Foluke
- Date: 2018
- Subjects: Education -- Parent participation -- South Africa
- Language: English
- Type: Thesis , Doctoral , Education
- Identifier: http://hdl.handle.net/10353/10497 , vital:35497
- Description: This investigation springs from the realization that academic achievement is influenced by different environmental factors. The influence of parental involvement on learners’ academic achievement has been recognized globally by experts in the education industry. As integral as parental involvement is, education industry is yet to come to terms on the best type of parental involvement needed for the teaching and learning of Mathematics in high schools especially at the transition phase. The aim of this study was to establish the relationship between parental involvement and grade 8 learners’ academic achievement in Mathematics. Quantitative research method was used for data collection. The data was collected with the use of parental involvement questionnaire for learners (PIQL) and learners Mathematics academic achievement scores. The research was conducted in six schools (public and private) within the East London Education District. The total sample size was 460 Grade 8 learners who were randomly selected across the board. The outcomes of the investigation revealed that parental involvement enhances the academic achievement of grade 8 learners irrespective of a definition of it or the measure of achievement. Furthermore, the results of this findings indicate that good parenting styles, parental support and parental educational background (r = 0.54; P < 0.05), (r =0.20; P< 0.05), (r = 0.68; P < 0.05) respectively are prerequisite for learners’ academic achievement in mathematics, showing that the variables are significantly related to learners academic achievement in mathematics; while parental involvement in the area of communication and family structure were very weak (r = 0.05; P > 0.05), (R=0.09; R2=.005; P < 0.05). This study therefore, recommended that parental involvement should be beefed up especially in areas of communication and family structure, by both the parents and teachers in order to enhance learners’ academic achievement in Mathematics.
- Full Text:
- Date Issued: 2018
- Authors: Eesuola, Omobola Foluke
- Date: 2018
- Subjects: Education -- Parent participation -- South Africa
- Language: English
- Type: Thesis , Doctoral , Education
- Identifier: http://hdl.handle.net/10353/10497 , vital:35497
- Description: This investigation springs from the realization that academic achievement is influenced by different environmental factors. The influence of parental involvement on learners’ academic achievement has been recognized globally by experts in the education industry. As integral as parental involvement is, education industry is yet to come to terms on the best type of parental involvement needed for the teaching and learning of Mathematics in high schools especially at the transition phase. The aim of this study was to establish the relationship between parental involvement and grade 8 learners’ academic achievement in Mathematics. Quantitative research method was used for data collection. The data was collected with the use of parental involvement questionnaire for learners (PIQL) and learners Mathematics academic achievement scores. The research was conducted in six schools (public and private) within the East London Education District. The total sample size was 460 Grade 8 learners who were randomly selected across the board. The outcomes of the investigation revealed that parental involvement enhances the academic achievement of grade 8 learners irrespective of a definition of it or the measure of achievement. Furthermore, the results of this findings indicate that good parenting styles, parental support and parental educational background (r = 0.54; P < 0.05), (r =0.20; P< 0.05), (r = 0.68; P < 0.05) respectively are prerequisite for learners’ academic achievement in mathematics, showing that the variables are significantly related to learners academic achievement in mathematics; while parental involvement in the area of communication and family structure were very weak (r = 0.05; P > 0.05), (R=0.09; R2=.005; P < 0.05). This study therefore, recommended that parental involvement should be beefed up especially in areas of communication and family structure, by both the parents and teachers in order to enhance learners’ academic achievement in Mathematics.
- Full Text:
- Date Issued: 2018
Strategies teachers use to enhance grade 7 learners' reading comprehension skills in first additional language : four primary schools in Fort Beaufort
- Authors: Matakane, Euphimia Nobuzwe
- Date: 2018
- Subjects: English language -- Study and teaching -- South Africa -- Eastern Cape Reading comprehension -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , Education
- Identifier: http://hdl.handle.net/10353/9533 , vital:34363
- Description: This study focused on the strategies teachers use to enhance grade 7 learners’ reading comprehension skills in English First Additional Language at Fort Beaufort District. This study was impelled by low performance of learners in English language, where learners were unable to read and answer questions promptly due lack of understanding what they read. This study is qualitative in approach and underpinned interpretive paradigm position. Fort Beaufort Education District used as a case study whereby four schools were purposively selected and each with six grade seven learners, teachers and Subject Advisor. Qualitative data was gathered through semi-structured interviews, focus group interviews, observations and documents analysis. Interviews and focus groups discussions were taped, transcribed, analysed and the data was categorised into themes. The findings of this study disclosed the weak correlation between teachers’ knowledge and teaching practices and lack of support from the district. The participating teachers had limited understanding of reading comprehension strategies; as a result, they regarded teaching reading comprehension as a challenge since they do not know what comprehension strategies are, and how to apply them. Teachers lack theoretical knowledge and practice concerning the teaching of reading for comprehension resulted to a negative attitude and a total neglect towards teaching reading for comprehension. The participants showed dissatisfaction with the intervention of the Department of Education and the policies they impose on them. The Curriculum and Assessment Policy Statement has no clear guidelines on how to teach these strategies of reading comprehension, rather it places reading comprehension under three phases, namely: Pre-reading, During- reading and Post-reading. As they lack appropriate techniques to teach English comprehension effectively, more workshops should be done to empower them in order to become competent teachers. Teachers need more training on active approaches in order to change their comprehension instruction and to select texts that are relevant to learners’ life situations or experiences, in order for them to relate with the text and thus would cause them to read with understanding.
- Full Text:
- Date Issued: 2018
- Authors: Matakane, Euphimia Nobuzwe
- Date: 2018
- Subjects: English language -- Study and teaching -- South Africa -- Eastern Cape Reading comprehension -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , Education
- Identifier: http://hdl.handle.net/10353/9533 , vital:34363
- Description: This study focused on the strategies teachers use to enhance grade 7 learners’ reading comprehension skills in English First Additional Language at Fort Beaufort District. This study was impelled by low performance of learners in English language, where learners were unable to read and answer questions promptly due lack of understanding what they read. This study is qualitative in approach and underpinned interpretive paradigm position. Fort Beaufort Education District used as a case study whereby four schools were purposively selected and each with six grade seven learners, teachers and Subject Advisor. Qualitative data was gathered through semi-structured interviews, focus group interviews, observations and documents analysis. Interviews and focus groups discussions were taped, transcribed, analysed and the data was categorised into themes. The findings of this study disclosed the weak correlation between teachers’ knowledge and teaching practices and lack of support from the district. The participating teachers had limited understanding of reading comprehension strategies; as a result, they regarded teaching reading comprehension as a challenge since they do not know what comprehension strategies are, and how to apply them. Teachers lack theoretical knowledge and practice concerning the teaching of reading for comprehension resulted to a negative attitude and a total neglect towards teaching reading for comprehension. The participants showed dissatisfaction with the intervention of the Department of Education and the policies they impose on them. The Curriculum and Assessment Policy Statement has no clear guidelines on how to teach these strategies of reading comprehension, rather it places reading comprehension under three phases, namely: Pre-reading, During- reading and Post-reading. As they lack appropriate techniques to teach English comprehension effectively, more workshops should be done to empower them in order to become competent teachers. Teachers need more training on active approaches in order to change their comprehension instruction and to select texts that are relevant to learners’ life situations or experiences, in order for them to relate with the text and thus would cause them to read with understanding.
- Full Text:
- Date Issued: 2018
Reform-based approaches in the learning and teaching for conceptual understanding of calculus for diploma studies at south african university
- Authors: Coetzee, Johanna
- Date: 2017
- Subjects: Calculus Mathematics -- Study and teaching
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/4959 , vital:28878
- Description: This research tested whether Reform-Based Approaches (RBAs) in the learning and teaching of calculus could lead to improved conceptual understanding. The study adopted positivistic paradigm, quantitative approach and pre- and post-test in a quasi-experimental design. The theoretical framework was Constructivism. The interventions were grounded on learner-centred RBAs including Interactive Engagement (IE), Peer Discussion (PD) and Good Questions (GQ). The experimental group comprised 119 volunteering students from a population of 461 registered for Mathematics as a service subject for the National Diploma (ND) in science or engineering at a South African university. Those not in the experimental group were taught through teacher-centred traditional approaches which have been the norm. However, only 71 out of those in the traditionally taught cohort volunteered to write both Pre- and Post-tests. As such, the total number of subjects in the study was 190, i.e., 119 from the Reform-Based cohort and 71 from the Traditional cohort. The instrument, the Calculus Concept Inventory for Technicians (CCIT), consisted of 19 questions on functions, differentiation and integration. Based on a pilot test, the instrument was improved. The Reform-Based cohort did not receive any participation reward and test scores did not contribute to promotion scores. The students wrote Pre-tests in the second week after commencement of lectures and Post-tests during the last week of lectures. The data were analysed using various statistical tools, tests and measures such as Chi-squares, Student t-tests, Pearson’s Product Moment correlation, Cronbach alpha, KR-20, the Difficulty Index, and Item Discrimination Point Biserial Index (PBI). The raw gain and normalised gains were also employed in data analyses. The main finding of this study was that RBA made a significant impact on the conceptual understanding of calculus of the experimental group. The gain achieved by the experimental group was in a low range and corresponded to the low use of IE (25% of contact time). A combination of RBA with Traditional teaching is recommended. Also, RBA will be most successfully introduced if supplemented and complemented through supportive environments.
- Full Text:
- Date Issued: 2017
- Authors: Coetzee, Johanna
- Date: 2017
- Subjects: Calculus Mathematics -- Study and teaching
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/4959 , vital:28878
- Description: This research tested whether Reform-Based Approaches (RBAs) in the learning and teaching of calculus could lead to improved conceptual understanding. The study adopted positivistic paradigm, quantitative approach and pre- and post-test in a quasi-experimental design. The theoretical framework was Constructivism. The interventions were grounded on learner-centred RBAs including Interactive Engagement (IE), Peer Discussion (PD) and Good Questions (GQ). The experimental group comprised 119 volunteering students from a population of 461 registered for Mathematics as a service subject for the National Diploma (ND) in science or engineering at a South African university. Those not in the experimental group were taught through teacher-centred traditional approaches which have been the norm. However, only 71 out of those in the traditionally taught cohort volunteered to write both Pre- and Post-tests. As such, the total number of subjects in the study was 190, i.e., 119 from the Reform-Based cohort and 71 from the Traditional cohort. The instrument, the Calculus Concept Inventory for Technicians (CCIT), consisted of 19 questions on functions, differentiation and integration. Based on a pilot test, the instrument was improved. The Reform-Based cohort did not receive any participation reward and test scores did not contribute to promotion scores. The students wrote Pre-tests in the second week after commencement of lectures and Post-tests during the last week of lectures. The data were analysed using various statistical tools, tests and measures such as Chi-squares, Student t-tests, Pearson’s Product Moment correlation, Cronbach alpha, KR-20, the Difficulty Index, and Item Discrimination Point Biserial Index (PBI). The raw gain and normalised gains were also employed in data analyses. The main finding of this study was that RBA made a significant impact on the conceptual understanding of calculus of the experimental group. The gain achieved by the experimental group was in a low range and corresponded to the low use of IE (25% of contact time). A combination of RBA with Traditional teaching is recommended. Also, RBA will be most successfully introduced if supplemented and complemented through supportive environments.
- Full Text:
- Date Issued: 2017
Development and manufacture of sustained release captopril beads
- Authors: Mhaka, Farai Arthur
- Date: 2015
- Language: English
- Type: text , Thesis , Masters , MPharm
- Identifier: http://hdl.handle.net/10962/54712 , vital:26602
- Description: Hypertension has a high mortality rate in developing countries such as South Africa. Although the prevention and control of hypertension is a health priority, efforts to decrease the global burden of hypertension and improve control over the condition are inadequate. The use of angiotensin converting enzyme (ACE) inhibitors such as captopril (CPT) have been effective for the management of hypertension when used as first line therapy alone or in combination. Commercially available immediate release dosage forms containing 12.5, 25 and 50 mg of CPT are administered two or three times a day to treat hypertension. CPT degrades in aqueous media with the sulfhydryl functional moiety responsible for adverse effects such as hypersensitivity, taste disturbances and/or presenting with a dry hacking cough. CPT has a short elimination half-life of between 1.6 and 1.9 hours, which means that the compound is a suitable candidate for inclusion in sustained release (SR) dosage forms. Manufacturing a SR dosage form of coated beads for twice daily dosing may reduce the incidence and intensity of undesirable adverse effects, improve the stability of CPT and improve patient adherence. A stability indicating reversed-phase high performance liquid chromatographic (RP-HPLC) method was developed and optimised using a central composite design approach. As part of this approach the interactive effects of input factors, viz. pH, methanol (MeOH) content and column temperature on retention time, were investigated to achieve a separation with well-resolved and symmetrical peaks for CPT and salicylic acid. The method was validated using ICH guidelines and was found to be simple, linear, precise, accurate, selective and rapid for the in vitro quantitation of CPT. The method was successfully applied for the analysis of both commercially available and test formulations. Preformulation studies were undertaken to establish the physical and chemical properties of CPT, excipients and dosage forms to ensure the production of stabile and bioavailable products. Powder blends were assessed for flow properties using angle of repose (AOR), and bulk and tapped density, which were subsequently used to calculate Carr’s Index (CI) and the Hausner ratio (HR). The addition of talc resulted in the most powder blends with AOR, CI and HR that were within a range indicative of satisfactory to good flow properties. The use of talc was necessary to ensure that blending prior to wet granulation and extrusion-spheronisation would produce homogenous powders. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FT-IR) were used for the identification and purity of CPT alone and 1:1 binary mixtures with excipients in an effort to establish if CPT was likely to undergo physical and/or chemical modification during production. The DSC thermograms for all CPT-excipient mixtures revealed the presence of a melting endotherm that was wider, occurring at 110.93 °C (Tpeak for pure CPT). The characteristic peaks for specific functional groups were present in the FT-IR spectra for powder mixtures, indicating the absence of incompatibilities. Dialysis studies were used to investigate if the ammonium oleate present in Surelease® E-7-19010 interacted with CPT. The results suggests that an interaction between CPT and Surelease® E-7-19010 during processing of CPT beads was unlikely to occur. Preliminary investigations reveal that Methocel® K100M, Methocel® E4M, Avicel® PH102, Eudragit® RS PO, Surelease® E-7-19010 and talc are compatible with CPT and could be used for the manufacture of SR CPT beads. CPT beads were manufactured using extrusion-spheronisation and coated using a fluidised bed drier fitted with a Wurster insert. The amount of granulating fluid, coating levels, curing time and formulation composition were varied to achieve CPT release with specific criteria to develop a preliminary formulation. The coated beads met all desired quality attributes in respect of micromeritic and flow properties, content uniformity and friability. Response Surface Methodology was used to further optimise the SR CPT formulation. The Plackett-Burman design was used for this process to produce an SR dosage form with desirable quality attributes achieved by altering formulation composition, extrusion-spheronisation variables and coating parameters. ANOVA data revealed significant responses for yield, aspect ratio, sphericity, coating efficiency and cumulative percent CPT released at 2 and 12 hours. Formulations in which the high molecular weight HPMC were used in increased concentrations resulted in the formation of a sticky wet mass and extrudate, resulting in a decrease in yield. The application of a permeable, but insoluble Surelease® coat onto the surface of the beads formed a barrier that complements the activity of the hydrophilic matrix in preventing rapid dissolution and retarding the release of CPT from the beads. The amount of CPT released over 12 hours revealed that increasing the Methocel® K100M content entrapped CPT and retained it more efficiently in the hydrated matrix, resulting in a slow rate of CPT release. In vitro release data were fitted to a number of models in an attempt to elucidate mechanistic aspects of transport processes specific to CPT from the coated bead formulations. The results of fitting data from optimised batches revealed that the goodness of fit based on the adjusted correlation coefficient ranged between 0.953 and 0.976 for the Higuchi model, indicating that diffusion is a predominant factor that controls CPT release from the coated beads. The results of fitting data to the Korsmeyer-Peppas model suggest that the mechanism of CPT release includes transport of the dissolution medium from the vessel reservoir into the core of the bead due to osmotic potential, dissolution of CPT, mass transfer of the dissolved CPT within the core, partitioning between the solution and polymeric film, mass transfer of dissolved CPT through the film to ultimately reach the bulk dissolution fluid. A SR CPT bead formulation that has potential for further development and optimisation for scaled-up production using RSM approaches and Design of Experiments such as CCD or Box-Behnken has been successfully developed and manufactured using extrusion, spheronisation and coating processes. Assessment of all batches of beads manufactured exhibited satisfactory to good flow properties and demonstrated SR profiles over 12 hours that met USP criteria for SR dosage forms.
- Full Text:
- Date Issued: 2015
- Authors: Mhaka, Farai Arthur
- Date: 2015
- Language: English
- Type: text , Thesis , Masters , MPharm
- Identifier: http://hdl.handle.net/10962/54712 , vital:26602
- Description: Hypertension has a high mortality rate in developing countries such as South Africa. Although the prevention and control of hypertension is a health priority, efforts to decrease the global burden of hypertension and improve control over the condition are inadequate. The use of angiotensin converting enzyme (ACE) inhibitors such as captopril (CPT) have been effective for the management of hypertension when used as first line therapy alone or in combination. Commercially available immediate release dosage forms containing 12.5, 25 and 50 mg of CPT are administered two or three times a day to treat hypertension. CPT degrades in aqueous media with the sulfhydryl functional moiety responsible for adverse effects such as hypersensitivity, taste disturbances and/or presenting with a dry hacking cough. CPT has a short elimination half-life of between 1.6 and 1.9 hours, which means that the compound is a suitable candidate for inclusion in sustained release (SR) dosage forms. Manufacturing a SR dosage form of coated beads for twice daily dosing may reduce the incidence and intensity of undesirable adverse effects, improve the stability of CPT and improve patient adherence. A stability indicating reversed-phase high performance liquid chromatographic (RP-HPLC) method was developed and optimised using a central composite design approach. As part of this approach the interactive effects of input factors, viz. pH, methanol (MeOH) content and column temperature on retention time, were investigated to achieve a separation with well-resolved and symmetrical peaks for CPT and salicylic acid. The method was validated using ICH guidelines and was found to be simple, linear, precise, accurate, selective and rapid for the in vitro quantitation of CPT. The method was successfully applied for the analysis of both commercially available and test formulations. Preformulation studies were undertaken to establish the physical and chemical properties of CPT, excipients and dosage forms to ensure the production of stabile and bioavailable products. Powder blends were assessed for flow properties using angle of repose (AOR), and bulk and tapped density, which were subsequently used to calculate Carr’s Index (CI) and the Hausner ratio (HR). The addition of talc resulted in the most powder blends with AOR, CI and HR that were within a range indicative of satisfactory to good flow properties. The use of talc was necessary to ensure that blending prior to wet granulation and extrusion-spheronisation would produce homogenous powders. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FT-IR) were used for the identification and purity of CPT alone and 1:1 binary mixtures with excipients in an effort to establish if CPT was likely to undergo physical and/or chemical modification during production. The DSC thermograms for all CPT-excipient mixtures revealed the presence of a melting endotherm that was wider, occurring at 110.93 °C (Tpeak for pure CPT). The characteristic peaks for specific functional groups were present in the FT-IR spectra for powder mixtures, indicating the absence of incompatibilities. Dialysis studies were used to investigate if the ammonium oleate present in Surelease® E-7-19010 interacted with CPT. The results suggests that an interaction between CPT and Surelease® E-7-19010 during processing of CPT beads was unlikely to occur. Preliminary investigations reveal that Methocel® K100M, Methocel® E4M, Avicel® PH102, Eudragit® RS PO, Surelease® E-7-19010 and talc are compatible with CPT and could be used for the manufacture of SR CPT beads. CPT beads were manufactured using extrusion-spheronisation and coated using a fluidised bed drier fitted with a Wurster insert. The amount of granulating fluid, coating levels, curing time and formulation composition were varied to achieve CPT release with specific criteria to develop a preliminary formulation. The coated beads met all desired quality attributes in respect of micromeritic and flow properties, content uniformity and friability. Response Surface Methodology was used to further optimise the SR CPT formulation. The Plackett-Burman design was used for this process to produce an SR dosage form with desirable quality attributes achieved by altering formulation composition, extrusion-spheronisation variables and coating parameters. ANOVA data revealed significant responses for yield, aspect ratio, sphericity, coating efficiency and cumulative percent CPT released at 2 and 12 hours. Formulations in which the high molecular weight HPMC were used in increased concentrations resulted in the formation of a sticky wet mass and extrudate, resulting in a decrease in yield. The application of a permeable, but insoluble Surelease® coat onto the surface of the beads formed a barrier that complements the activity of the hydrophilic matrix in preventing rapid dissolution and retarding the release of CPT from the beads. The amount of CPT released over 12 hours revealed that increasing the Methocel® K100M content entrapped CPT and retained it more efficiently in the hydrated matrix, resulting in a slow rate of CPT release. In vitro release data were fitted to a number of models in an attempt to elucidate mechanistic aspects of transport processes specific to CPT from the coated bead formulations. The results of fitting data from optimised batches revealed that the goodness of fit based on the adjusted correlation coefficient ranged between 0.953 and 0.976 for the Higuchi model, indicating that diffusion is a predominant factor that controls CPT release from the coated beads. The results of fitting data to the Korsmeyer-Peppas model suggest that the mechanism of CPT release includes transport of the dissolution medium from the vessel reservoir into the core of the bead due to osmotic potential, dissolution of CPT, mass transfer of the dissolved CPT within the core, partitioning between the solution and polymeric film, mass transfer of dissolved CPT through the film to ultimately reach the bulk dissolution fluid. A SR CPT bead formulation that has potential for further development and optimisation for scaled-up production using RSM approaches and Design of Experiments such as CCD or Box-Behnken has been successfully developed and manufactured using extrusion, spheronisation and coating processes. Assessment of all batches of beads manufactured exhibited satisfactory to good flow properties and demonstrated SR profiles over 12 hours that met USP criteria for SR dosage forms.
- Full Text:
- Date Issued: 2015
A critical analysis of the grammar of isiXhosa as used in the Revised Union version of the Bible
- Oosthuysen, Jacobus Christiaan
- Authors: Oosthuysen, Jacobus Christiaan
- Date: 2013
- Subjects: Bible -- Xhosa -- Revised Union -- 1942 Xhosa language -- Grammar -- Research Xhosa language -- Texts
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3555 , http://hdl.handle.net/10962/d1001625
- Description: This study provides a description and critical analysis of the grammatical structure of isiXhosa as used in the Revised Union Version of the Bible, published in 1942 and republished in 1975. This translation records what was regarded as proper isiXhosa at the beginning of the 20th century, reflecting the consensus inter alia of prominent isiXhosa writers, such as W.B. Rubusana, J.H. Soga, C. Koti, Y. Mbali and D. D. T. Jabavu, who served on the committee that produced the revision. In this study isiXhosa is described in its own right, without approaching it with preconceived ideas derived from other languages. That is to say this is a phenomenological analysis describing the grammatical structures of isiXhosa as they present themselves to the analyst. It is comprehensive, with no structure being overlooked or being described in such a manner that it complicates an understanding of other structures. In the first chapter the context of the research and a brief outline of the historical growth in understanding the structure of isiXhosa are set out and the goals and the method followed in this study are described. In the following chapters the findings of this study are presented. The initial focus is on isiXhosa phonology and the orthography used to put it to writing. Then isiXhosa morphology and syntax is set out. Initially the substantives, i.e. the nouns and pronouns in their distinctive classes and forms, and how they are qualified, receive attention. Then the predicates are explored, i.e. the verbs and copulatives, as linked to the substantives with concords, and reflecting various moods, tenses, actualities and aspects. Finally attention is given to ideophones and interjections and words that can be grouped together as adverbs, conjunctions, avoidance words and numerals. In the concluding chapter consideration is given to the question of whether this study has in fact achieved the aim of setting out a description of the structure of isiXhosa based solely on the language itself, free of preconceived ideas, and attention is drawn to insights gained in respect of the true nature of the isiXhosa grammatical structures, such as, for example, the variable prefix qualificative nouns, traditionally referred to as adjectives. This study is therefore a revisionist study in the sense that it reinvents isiXhosa as a language in its own right, free from Western influenced perspectives.
- Full Text:
- Date Issued: 2013
- Authors: Oosthuysen, Jacobus Christiaan
- Date: 2013
- Subjects: Bible -- Xhosa -- Revised Union -- 1942 Xhosa language -- Grammar -- Research Xhosa language -- Texts
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3555 , http://hdl.handle.net/10962/d1001625
- Description: This study provides a description and critical analysis of the grammatical structure of isiXhosa as used in the Revised Union Version of the Bible, published in 1942 and republished in 1975. This translation records what was regarded as proper isiXhosa at the beginning of the 20th century, reflecting the consensus inter alia of prominent isiXhosa writers, such as W.B. Rubusana, J.H. Soga, C. Koti, Y. Mbali and D. D. T. Jabavu, who served on the committee that produced the revision. In this study isiXhosa is described in its own right, without approaching it with preconceived ideas derived from other languages. That is to say this is a phenomenological analysis describing the grammatical structures of isiXhosa as they present themselves to the analyst. It is comprehensive, with no structure being overlooked or being described in such a manner that it complicates an understanding of other structures. In the first chapter the context of the research and a brief outline of the historical growth in understanding the structure of isiXhosa are set out and the goals and the method followed in this study are described. In the following chapters the findings of this study are presented. The initial focus is on isiXhosa phonology and the orthography used to put it to writing. Then isiXhosa morphology and syntax is set out. Initially the substantives, i.e. the nouns and pronouns in their distinctive classes and forms, and how they are qualified, receive attention. Then the predicates are explored, i.e. the verbs and copulatives, as linked to the substantives with concords, and reflecting various moods, tenses, actualities and aspects. Finally attention is given to ideophones and interjections and words that can be grouped together as adverbs, conjunctions, avoidance words and numerals. In the concluding chapter consideration is given to the question of whether this study has in fact achieved the aim of setting out a description of the structure of isiXhosa based solely on the language itself, free of preconceived ideas, and attention is drawn to insights gained in respect of the true nature of the isiXhosa grammatical structures, such as, for example, the variable prefix qualificative nouns, traditionally referred to as adjectives. This study is therefore a revisionist study in the sense that it reinvents isiXhosa as a language in its own right, free from Western influenced perspectives.
- Full Text:
- Date Issued: 2013
An exploration of conditions enabling and constraining the infusion of service-learning into the curriculum at a South African research led university
- Authors: Hlengwa, Amanda Immaculate
- Date: 2013
- Subjects: Rhodes University -- Curricula -- Evaluation Service learning -- Research -- South Africa Education, Higher -- Curricula -- South Africa -- Evaluation Curriculum planning -- Research -- South Africa Experiential learning -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1888 , http://hdl.handle.net/10962/d1006036
- Description: Drawing on critical realist philosophy as a meta-theoretical framework, this study explores the conditions that enable and constrain the infusion of service-learning in university curricula. In this study, four discipline-based cases are analysed within the context of an overarching case of one South African university. The study reports on case study research into four disciplines, broadly representing the disciplinary array offered at Rhodes University, a small traditional research-intensive university in South Africa – four cases are thus embedded within a larger over-arching case. Margret Archer’s analytical dualism is used as an analytical lens for the inquiry. It offers tools for examining the conditions for the emergence of service learning and the form it takes in each case. Archer’s framework requires the artificial separation of structural, cultural and agential mechanisms for analytical purposes in order to establish the dominant factors impacting on the infusion of service-learning in curricula. An analysis of the interplay between structure, culture and agency uncovers insights into the conditions that enable or constrain the adoption of service learning as a pedagogic tool in specific disciplines. Curriculum decision-making is a central consideration in this study. Basil Bernstein’s theory of cultural transmission provides an external language of description to theorise the pedagogic choices made in specific contexts. This body of theory provides analytical tools for generating nuanced explanations of the significance of knowledge and curriculum structures as enabling and constraining mechanisms when pedagogic decisions are made. The study shows that the nature of the discipline has a significant influence on the emergence of service-learning and the form it takes in each context. Key agents draw on available structural and cultural mechanisms to either maintain the status quo or they exercise their personal properties and powers to mitigate existing conditions. The first case examines the emergence of service-learning in a ‘hard pure’ discipline where structural and cultural conditions constrain the emergence of innovative pedagogic tools. In this case a key agent draws on a confluence of personal, structural and cultural emergent properties to initiate a service-learning course at the honours level. Factors that make service-learning possible in this case include the key agent’s seniority within the institution, his status as a prolific researcher, the possibilities for application of disciplinary knowledge, and a strong institutional discourse of service to society (RU in Society) and an institutional and departmental discourse privileging academic freedom. In the second case the conditions in the ‘hard applied’ discipline are largely enabling, however the emergence of service-learning is facilitated by the interplay of the following agential, structural and cultural emergent properties: corporate agency taking advantage of the outward focus of the discipline (a region in Bernsteinian terms) and drawing on what is termed the RU in Society discourse. The third case represents a ‘soft pure’ discipline, where service-learning does not emerge within the formal curriculum, but in a largely marginalised departmental outreach programme. This discipline is inward facing and although its knowledge base draws on challenges and phenomena in society, it remains at an esoteric level accessible mainly to the discipline community. Agents in this department draw on the insular structure of the discipline, in conjunction with the strong Academic Freedom discourse to develop a form of service-learning that furthers disciplinary aims, albeit within the context of limited engagement beyond the boundaries of the discipline and the institution. In the case of the ‘soft applied’ discipline the structural and cultural conditions are largely enabling. However the emergence of service-learning in this discipline relies on the advocacy of a powerful social agent in the department with an interest in socially equitable practice; she draws on the RU in Society discourse to promote direct engagement with communities beyond the university boundaries. The study is set in a research-intensive university and it is perhaps not surprising that the service-learning courses in three of the four cases are framed by research projects. This suggests that in the context of this kind of institution it may be imperative to draw on research activities as the basis of infusing service-learning in the curriculum. The findings of this study challenge the implicit assumption in policy documents that it is possible to institute service-learning in all disciplines.
- Full Text:
- Date Issued: 2013
- Authors: Hlengwa, Amanda Immaculate
- Date: 2013
- Subjects: Rhodes University -- Curricula -- Evaluation Service learning -- Research -- South Africa Education, Higher -- Curricula -- South Africa -- Evaluation Curriculum planning -- Research -- South Africa Experiential learning -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1888 , http://hdl.handle.net/10962/d1006036
- Description: Drawing on critical realist philosophy as a meta-theoretical framework, this study explores the conditions that enable and constrain the infusion of service-learning in university curricula. In this study, four discipline-based cases are analysed within the context of an overarching case of one South African university. The study reports on case study research into four disciplines, broadly representing the disciplinary array offered at Rhodes University, a small traditional research-intensive university in South Africa – four cases are thus embedded within a larger over-arching case. Margret Archer’s analytical dualism is used as an analytical lens for the inquiry. It offers tools for examining the conditions for the emergence of service learning and the form it takes in each case. Archer’s framework requires the artificial separation of structural, cultural and agential mechanisms for analytical purposes in order to establish the dominant factors impacting on the infusion of service-learning in curricula. An analysis of the interplay between structure, culture and agency uncovers insights into the conditions that enable or constrain the adoption of service learning as a pedagogic tool in specific disciplines. Curriculum decision-making is a central consideration in this study. Basil Bernstein’s theory of cultural transmission provides an external language of description to theorise the pedagogic choices made in specific contexts. This body of theory provides analytical tools for generating nuanced explanations of the significance of knowledge and curriculum structures as enabling and constraining mechanisms when pedagogic decisions are made. The study shows that the nature of the discipline has a significant influence on the emergence of service-learning and the form it takes in each context. Key agents draw on available structural and cultural mechanisms to either maintain the status quo or they exercise their personal properties and powers to mitigate existing conditions. The first case examines the emergence of service-learning in a ‘hard pure’ discipline where structural and cultural conditions constrain the emergence of innovative pedagogic tools. In this case a key agent draws on a confluence of personal, structural and cultural emergent properties to initiate a service-learning course at the honours level. Factors that make service-learning possible in this case include the key agent’s seniority within the institution, his status as a prolific researcher, the possibilities for application of disciplinary knowledge, and a strong institutional discourse of service to society (RU in Society) and an institutional and departmental discourse privileging academic freedom. In the second case the conditions in the ‘hard applied’ discipline are largely enabling, however the emergence of service-learning is facilitated by the interplay of the following agential, structural and cultural emergent properties: corporate agency taking advantage of the outward focus of the discipline (a region in Bernsteinian terms) and drawing on what is termed the RU in Society discourse. The third case represents a ‘soft pure’ discipline, where service-learning does not emerge within the formal curriculum, but in a largely marginalised departmental outreach programme. This discipline is inward facing and although its knowledge base draws on challenges and phenomena in society, it remains at an esoteric level accessible mainly to the discipline community. Agents in this department draw on the insular structure of the discipline, in conjunction with the strong Academic Freedom discourse to develop a form of service-learning that furthers disciplinary aims, albeit within the context of limited engagement beyond the boundaries of the discipline and the institution. In the case of the ‘soft applied’ discipline the structural and cultural conditions are largely enabling. However the emergence of service-learning in this discipline relies on the advocacy of a powerful social agent in the department with an interest in socially equitable practice; she draws on the RU in Society discourse to promote direct engagement with communities beyond the university boundaries. The study is set in a research-intensive university and it is perhaps not surprising that the service-learning courses in three of the four cases are framed by research projects. This suggests that in the context of this kind of institution it may be imperative to draw on research activities as the basis of infusing service-learning in the curriculum. The findings of this study challenge the implicit assumption in policy documents that it is possible to institute service-learning in all disciplines.
- Full Text:
- Date Issued: 2013
The geochemistry of ore fluids and control of gold mineralization in banded iron-formation at the Kalahari Goldridge deposit, Kraaipan greenstone belt, South Africa
- Authors: Hammond, Napoleon Quaye
- Date: 2003
- Subjects: Gold ores -- Geology -- South Africa -- North-West Greenstone belts -- South Africa -- North-West Ore deposits -- South Africa -- North-West Geochemistry -- South Africa -- North-West
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5048 , http://hdl.handle.net/10962/d1008370
- Description: The Kalahari Goldridge mine is located within the Archaean Kraaipan Greenstone Belt about 60 km SW of Mafikeng in the Northwestern Province, South Africa. Several gold deposits are located within approximately north - south-striking banded iron-formation (BIF). Current opencast mining operations are focused on the largest of these (D Zone). The orebody is stratabound and hosted primarily in the BIF, which consists of alternating chert and magnetite-chloritestilpnomelane-sulphide-carbonate bands ranging from mm to cm scale. The ore body varies in thickness from 15 to 45 m along a strike length of about 1.5 km. The BlF is sandwiched between a sericite-carbonate-chlorite schist at the immediate footwall and carbonaceous meta-pelites in the hanging-wall. Further west in the footwall, the schists are underlain by mafic meta-volcanic amphibolite. Overlying the hanging-wall carbonaceous metapeiites are schist units and meta-greywackes that become increasingly conglomeratic up the stratigraphy. Stilpnomelane-, chlorite- and minnesotaite-bearing assemblages in the BlFs indicate metamorphic temperatures of 300 - 450°C and pressures of less than 5 kbars. The BIF generally strikes approximately 3400 and dips from 60 to 75°E. Brittle-ductile deformation is evidenced by small-scale isoclinal folds, brecciation, extension fractures and boudinaging of cherty BIF units. Fold axial planes are sub-parallel to the foliation orientation with sub-vertical plunges parallel to prominent rodding and mineral lineation in the footwall. Gold mineralization at the Kalahari Goldridge deposit is associated with two generations of subhorizontal quartz-carbonate veins dips approximately 20 to 40°W. The first generation consists of ladder vein sets (Group lIA) preferentially developed in Fe-rich meso bands, whilst the second generation consists of large quartz-carbonate veins (Group lIB), which crosscut the entire ore body extending into the footwall and hanging-wall in places. Major structures that control the ore body are related to meso-scale isoclinal folds with fold axes subparallel to mineral elongation lineations, which plunge approximately 067°E. These linear structures form orthogonal orientation with the plane of the mineralized shallowdipping veins indicating stretching and development of fluid - focusing conduits. A second-order controlling feature corresponds to the intersection of the mineralized veins and foliation planes of host rock, plunging approximately 008°N and trending 341°. G0ld is closely associated with sulphides, mainly pyrite and pyrrhotite and to a lesser extent with bismuth tellurides, and carbonate gangue. The ore fluid responsible for the gold deposition is in the C-O-H system with increased CH₄ contents attributed to localized hydrolysis reaction between interbedded carbonaceous sediment and ore fluid. The fluid is characterized by significant C0₂ contents and low salinities below 7.0 wt % NaCl equivalent (averages of 3.5 and 3.0 wt % NaCl equivalent for the first and second episodes of the mineralization respectively) . Calculated values of f0₂. ranging from 10⁻²⁹·⁹⁸ to 10⁻³²·⁹⁶ bars, bracket the C0₂-CH₄ and pyrite-pyrrhotite-magnetite buffer boundaries and reveal the reducing nature of the ore fluid at deposition. Calculated total sulphur content in the ore fluid (mΣs), ranges from 0.011 to 0.018M and is consistent with the range (10⁻³·⁵ to 10⁻¹M) reported for subamphibolite facies ore fluids. The close association of sulphides with the Au and nature of the fluid also give credence that the Au was carried in solution by the Au(HS)₂ - complex. Extensive epigenetic replacement of magnetite and chlorite in BIF and other meta-pelitic sediments in the deposit by sulphides and carbonates, both on meso scopic and microscopic scales gives evidence of an interaction by a CO₂- and H₂S-bearing fluid with the Fe-rich host rocks in the deposit. This facilitated Au precipitation due to changes in the physico-chemical conditions of the ore fluid such as a decrease in the mΣs and pH leading to the destabilization of the reduced sulphur complexes. Local gradients in f0₂ may account for gold precipitation in places within carbonaceous sediments. The fineness of the gold grams (1000*Au/(Au + Ag) ranges from 823 to 921. This compares favourably with the fineness reported for some Archaean BIFhosced deposits (851 - 970). Mass balance transfer calculations indicate that major chemical changes associated with the hydrothermal alteration of BIF include enrichment of Au, Ag, Bi, Te, volatiles (S and CO₂), MgO, Ba, K and Rb but significant depletion of SiO₂ and minor losses of Fe₂O₃. In addition, anomalous enrichment of Sc (average, 1247%) suggests its possible use as an exploration tool in the ferruginous sediments in the Kraaipan greenstone terrane. Evidence from light stable isotopes and fluid inclusions suggests that the mineralized veins crystallized from a single homogeneous fluid source during the two episodes of mineralization under the similar physicochemical conditions. Deposition occurred at temperatures rangmg from 350 to 400°C and fluid pressures ranging from 0.7 to 2.0kbars. Stable isotope constraints indicate the following range for the hydrothermal fluid; θ¹⁸H₂O = 6.65 to 10.48%0, 8¹³CΣc = -6.0 to -8.0 %0 and 8³⁴SΣs = + 1.69 to + 4.0%0 . These data do not offer conclusive evidence for the source of fluid associated with the mineralization at the Kalahari Goldridge deposit as they overlap the range prescribed for fluid derived from devolatization of deep-seated volcano-sedimentary piles near the brittle-ductile transition in greenstone belts during prograde metamorphism, and magmatic hydrothermal fluids. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2003
- Authors: Hammond, Napoleon Quaye
- Date: 2003
- Subjects: Gold ores -- Geology -- South Africa -- North-West Greenstone belts -- South Africa -- North-West Ore deposits -- South Africa -- North-West Geochemistry -- South Africa -- North-West
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5048 , http://hdl.handle.net/10962/d1008370
- Description: The Kalahari Goldridge mine is located within the Archaean Kraaipan Greenstone Belt about 60 km SW of Mafikeng in the Northwestern Province, South Africa. Several gold deposits are located within approximately north - south-striking banded iron-formation (BIF). Current opencast mining operations are focused on the largest of these (D Zone). The orebody is stratabound and hosted primarily in the BIF, which consists of alternating chert and magnetite-chloritestilpnomelane-sulphide-carbonate bands ranging from mm to cm scale. The ore body varies in thickness from 15 to 45 m along a strike length of about 1.5 km. The BlF is sandwiched between a sericite-carbonate-chlorite schist at the immediate footwall and carbonaceous meta-pelites in the hanging-wall. Further west in the footwall, the schists are underlain by mafic meta-volcanic amphibolite. Overlying the hanging-wall carbonaceous metapeiites are schist units and meta-greywackes that become increasingly conglomeratic up the stratigraphy. Stilpnomelane-, chlorite- and minnesotaite-bearing assemblages in the BlFs indicate metamorphic temperatures of 300 - 450°C and pressures of less than 5 kbars. The BIF generally strikes approximately 3400 and dips from 60 to 75°E. Brittle-ductile deformation is evidenced by small-scale isoclinal folds, brecciation, extension fractures and boudinaging of cherty BIF units. Fold axial planes are sub-parallel to the foliation orientation with sub-vertical plunges parallel to prominent rodding and mineral lineation in the footwall. Gold mineralization at the Kalahari Goldridge deposit is associated with two generations of subhorizontal quartz-carbonate veins dips approximately 20 to 40°W. The first generation consists of ladder vein sets (Group lIA) preferentially developed in Fe-rich meso bands, whilst the second generation consists of large quartz-carbonate veins (Group lIB), which crosscut the entire ore body extending into the footwall and hanging-wall in places. Major structures that control the ore body are related to meso-scale isoclinal folds with fold axes subparallel to mineral elongation lineations, which plunge approximately 067°E. These linear structures form orthogonal orientation with the plane of the mineralized shallowdipping veins indicating stretching and development of fluid - focusing conduits. A second-order controlling feature corresponds to the intersection of the mineralized veins and foliation planes of host rock, plunging approximately 008°N and trending 341°. G0ld is closely associated with sulphides, mainly pyrite and pyrrhotite and to a lesser extent with bismuth tellurides, and carbonate gangue. The ore fluid responsible for the gold deposition is in the C-O-H system with increased CH₄ contents attributed to localized hydrolysis reaction between interbedded carbonaceous sediment and ore fluid. The fluid is characterized by significant C0₂ contents and low salinities below 7.0 wt % NaCl equivalent (averages of 3.5 and 3.0 wt % NaCl equivalent for the first and second episodes of the mineralization respectively) . Calculated values of f0₂. ranging from 10⁻²⁹·⁹⁸ to 10⁻³²·⁹⁶ bars, bracket the C0₂-CH₄ and pyrite-pyrrhotite-magnetite buffer boundaries and reveal the reducing nature of the ore fluid at deposition. Calculated total sulphur content in the ore fluid (mΣs), ranges from 0.011 to 0.018M and is consistent with the range (10⁻³·⁵ to 10⁻¹M) reported for subamphibolite facies ore fluids. The close association of sulphides with the Au and nature of the fluid also give credence that the Au was carried in solution by the Au(HS)₂ - complex. Extensive epigenetic replacement of magnetite and chlorite in BIF and other meta-pelitic sediments in the deposit by sulphides and carbonates, both on meso scopic and microscopic scales gives evidence of an interaction by a CO₂- and H₂S-bearing fluid with the Fe-rich host rocks in the deposit. This facilitated Au precipitation due to changes in the physico-chemical conditions of the ore fluid such as a decrease in the mΣs and pH leading to the destabilization of the reduced sulphur complexes. Local gradients in f0₂ may account for gold precipitation in places within carbonaceous sediments. The fineness of the gold grams (1000*Au/(Au + Ag) ranges from 823 to 921. This compares favourably with the fineness reported for some Archaean BIFhosced deposits (851 - 970). Mass balance transfer calculations indicate that major chemical changes associated with the hydrothermal alteration of BIF include enrichment of Au, Ag, Bi, Te, volatiles (S and CO₂), MgO, Ba, K and Rb but significant depletion of SiO₂ and minor losses of Fe₂O₃. In addition, anomalous enrichment of Sc (average, 1247%) suggests its possible use as an exploration tool in the ferruginous sediments in the Kraaipan greenstone terrane. Evidence from light stable isotopes and fluid inclusions suggests that the mineralized veins crystallized from a single homogeneous fluid source during the two episodes of mineralization under the similar physicochemical conditions. Deposition occurred at temperatures rangmg from 350 to 400°C and fluid pressures ranging from 0.7 to 2.0kbars. Stable isotope constraints indicate the following range for the hydrothermal fluid; θ¹⁸H₂O = 6.65 to 10.48%0, 8¹³CΣc = -6.0 to -8.0 %0 and 8³⁴SΣs = + 1.69 to + 4.0%0 . These data do not offer conclusive evidence for the source of fluid associated with the mineralization at the Kalahari Goldridge deposit as they overlap the range prescribed for fluid derived from devolatization of deep-seated volcano-sedimentary piles near the brittle-ductile transition in greenstone belts during prograde metamorphism, and magmatic hydrothermal fluids. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2003
South African small business growth through interfirm linkages
- Authors: Toomey, David Colbert
- Date: 1999
- Subjects: Small business -- South Africa Interorganizational relations Small business -- South Africa -- Growth -- Case studies South Africa -- Economic policy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2836 , http://hdl.handle.net/10962/d1003046
- Description: Economic stagnation in sub-Saharan Africa since 1970 is well documented. While the causes are varied, the paradigm of nationalistic state-led economic development has changed. Economic development occurs in a global marketplace. Manufacturing has shifted from developed to less developed countries, an opportunity that was seized in Asia and Latin America. South Africa’s labour, unskilled and costly by world standards, is at a disadvantage as an agile and competitive world market seeks skilled labour at the lowest cost. South Africa’s Gear economic policy suggests that 300 000 new jobs need to be created annually until 2004 in order to reduce unemployment. Small, medium and microenterprise growth is central to meeting this target. Numerous government structures to assist small enterprises have been created. Few, however, assist small business with the demands of the marketplace. Most focus on generic skills training and questionable small business finance. This thesis suggests that interfirm linkages between large and small enterprises is one strategy that can assist the growth of small business, create employment and, increase labour skills. International experience shows that generic training is less effective in promoting small business than linking business training to actual market-demands. Interfirm linkages, most often through subcontracting, is a strategy used successfully in Taiwan, Indonesia, Malaysia and Brazil. Such linkages are usually government supported and provide incentives for both large and small businesses to work together productively. Three South African interfirm linkage case studies are critiqued. Case study findings indicate that interfirm linkages expose emerging businesses to market conditions, and can provide access to process technology training, low cost raw materials, creative finance, and new markets. Small business ‘learns by doing’ and also ‘learns while earning’. The state has a role in the development of a vibrant small, medium and microenterprise sector in South Africa. Current support strategies are largely unrelated to market conditions. Interfirm linkages are an approach that applies market forces in the development of small business. Government policy would be wisely directed to support such business interactions.
- Full Text:
- Date Issued: 1999
- Authors: Toomey, David Colbert
- Date: 1999
- Subjects: Small business -- South Africa Interorganizational relations Small business -- South Africa -- Growth -- Case studies South Africa -- Economic policy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2836 , http://hdl.handle.net/10962/d1003046
- Description: Economic stagnation in sub-Saharan Africa since 1970 is well documented. While the causes are varied, the paradigm of nationalistic state-led economic development has changed. Economic development occurs in a global marketplace. Manufacturing has shifted from developed to less developed countries, an opportunity that was seized in Asia and Latin America. South Africa’s labour, unskilled and costly by world standards, is at a disadvantage as an agile and competitive world market seeks skilled labour at the lowest cost. South Africa’s Gear economic policy suggests that 300 000 new jobs need to be created annually until 2004 in order to reduce unemployment. Small, medium and microenterprise growth is central to meeting this target. Numerous government structures to assist small enterprises have been created. Few, however, assist small business with the demands of the marketplace. Most focus on generic skills training and questionable small business finance. This thesis suggests that interfirm linkages between large and small enterprises is one strategy that can assist the growth of small business, create employment and, increase labour skills. International experience shows that generic training is less effective in promoting small business than linking business training to actual market-demands. Interfirm linkages, most often through subcontracting, is a strategy used successfully in Taiwan, Indonesia, Malaysia and Brazil. Such linkages are usually government supported and provide incentives for both large and small businesses to work together productively. Three South African interfirm linkage case studies are critiqued. Case study findings indicate that interfirm linkages expose emerging businesses to market conditions, and can provide access to process technology training, low cost raw materials, creative finance, and new markets. Small business ‘learns by doing’ and also ‘learns while earning’. The state has a role in the development of a vibrant small, medium and microenterprise sector in South Africa. Current support strategies are largely unrelated to market conditions. Interfirm linkages are an approach that applies market forces in the development of small business. Government policy would be wisely directed to support such business interactions.
- Full Text:
- Date Issued: 1999
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