The development of an arousal and anxiety control mental skills training programme for the Rhodes University archery club
- Authors: Chiweshe, Malvern Tatenda
- Date: 2013
- Subjects: Anxiety , Arousal , Mental skills , Training , Sports -- Psychological aspects -- Research -- South Africa , Archers -- Training of -- Research -- South Africa , Archers -- Psychological aspects -- Research -- South Africa , Psychology, Applied
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2917 , http://hdl.handle.net/10962/d1002082
- Description: Research on the development of Mental Skills Training (MST) programmes in sport psychology has largely increased as sport has become more competitive. MST programmes have been seen to improve the performance of athletes. This particular research study focuses on the development of an anxiety and arousal control MST programme designed specifically for, and tailored exclusively to, the needs of four archers from the Rhodes Archery Club in Grahamstown, Eastern Cape, South Africa. The development of the programme was guided by the Organisational Development Process model as the research methodology design. Data from two quantitative measures (CSAI-2 and Sport Grid-R), a focus group, and an individual interview were integrated with currently existing mental skills literature and theory to devise this particular MST programme. The results of the assessment phase showed that individual archers have different experiences in how anxiety and arousal affect their performances. The results also showed that archers have different zones in which they feel their performance is good. These zones depend on their subjective interpretations of anxiety and arousal. The results also showed that other factors that include personality differences, level of experience and level of expertise also influence how anxiety and arousal affect performance. The archers had previous exposure to MST programmes although they had not received systematic training in mental skills training. The programme was developed in the form of MST workshops that would run over a three week period. As part of the programme the archers would be given a mental skills manual to aid in the mental skills training. It is recommended in future that more research in MST programmes be done as a way of improving the performance of athletes in South Africa
- Full Text:
- Date Issued: 2013
- Authors: Chiweshe, Malvern Tatenda
- Date: 2013
- Subjects: Anxiety , Arousal , Mental skills , Training , Sports -- Psychological aspects -- Research -- South Africa , Archers -- Training of -- Research -- South Africa , Archers -- Psychological aspects -- Research -- South Africa , Psychology, Applied
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2917 , http://hdl.handle.net/10962/d1002082
- Description: Research on the development of Mental Skills Training (MST) programmes in sport psychology has largely increased as sport has become more competitive. MST programmes have been seen to improve the performance of athletes. This particular research study focuses on the development of an anxiety and arousal control MST programme designed specifically for, and tailored exclusively to, the needs of four archers from the Rhodes Archery Club in Grahamstown, Eastern Cape, South Africa. The development of the programme was guided by the Organisational Development Process model as the research methodology design. Data from two quantitative measures (CSAI-2 and Sport Grid-R), a focus group, and an individual interview were integrated with currently existing mental skills literature and theory to devise this particular MST programme. The results of the assessment phase showed that individual archers have different experiences in how anxiety and arousal affect their performances. The results also showed that archers have different zones in which they feel their performance is good. These zones depend on their subjective interpretations of anxiety and arousal. The results also showed that other factors that include personality differences, level of experience and level of expertise also influence how anxiety and arousal affect performance. The archers had previous exposure to MST programmes although they had not received systematic training in mental skills training. The programme was developed in the form of MST workshops that would run over a three week period. As part of the programme the archers would be given a mental skills manual to aid in the mental skills training. It is recommended in future that more research in MST programmes be done as a way of improving the performance of athletes in South Africa
- Full Text:
- Date Issued: 2013
The development of an e-Health system for health awareness campaigns in poor areas
- Gremu, Chikumbutso, Terzoli, Alfredo, Tsietsi, Mosiuoa
- Authors: Gremu, Chikumbutso , Terzoli, Alfredo , Tsietsi, Mosiuoa
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430638 , vital:72705 , 10.1109/ISTAFRICA.2015.7190527
- Description: This paper discusses work to develop an e-Health system called HealthAware to assist health service organisations to carry out targeted health awareness campaigns in poor areas. The system comprises two components called the Dashboard and the Health Messenger, which are web-based, Java applications that run in a peer-to-peer fashion. The Dashboard is used to create, manage, and publish awareness campaigns. The HealthMessenger facilitates end-users' access to the relevant awareness campaigns. A targeted communication strategy which splits the target population into subgroups based on their demo-graphic characteristics and geographic locations is used to determine relevant campaigns for a user. The HealthMessenger is hosted on an application service integration platform called TeleWeaver, while the Dashboard is hosted independently of TeleWeaver. Message queuing is used to ensure reliable communication between the Dashboard and the HealthMessenger. The implementation of HealthAware contributes knowledge on developing a system that ensures that users access only the information that is relevant to them. This addresses the challenge of sifting through potentially irrelevant information before arriving at the important information which is posed by generic materials.
- Full Text:
- Date Issued: 2015
- Authors: Gremu, Chikumbutso , Terzoli, Alfredo , Tsietsi, Mosiuoa
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430638 , vital:72705 , 10.1109/ISTAFRICA.2015.7190527
- Description: This paper discusses work to develop an e-Health system called HealthAware to assist health service organisations to carry out targeted health awareness campaigns in poor areas. The system comprises two components called the Dashboard and the Health Messenger, which are web-based, Java applications that run in a peer-to-peer fashion. The Dashboard is used to create, manage, and publish awareness campaigns. The HealthMessenger facilitates end-users' access to the relevant awareness campaigns. A targeted communication strategy which splits the target population into subgroups based on their demo-graphic characteristics and geographic locations is used to determine relevant campaigns for a user. The HealthMessenger is hosted on an application service integration platform called TeleWeaver, while the Dashboard is hosted independently of TeleWeaver. Message queuing is used to ensure reliable communication between the Dashboard and the HealthMessenger. The implementation of HealthAware contributes knowledge on developing a system that ensures that users access only the information that is relevant to them. This addresses the challenge of sifting through potentially irrelevant information before arriving at the important information which is posed by generic materials.
- Full Text:
- Date Issued: 2015
The development of an ecological model to determine flood release options for the management of the Phongolo floodplain in Kwazulu/Natal (South Africa)
- Authors: Weldrick, Sarah Katharine
- Date: 1996
- Subjects: Flood control -- Environmental aspects -- South Africa -- KwaZulu-Natal -- Pongolo floodplain , Fishes -- Behavior
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5258 , http://hdl.handle.net/10962/d1005102 , Flood control -- Environmental aspects -- South Africa -- KwaZulu-Natal -- Pongolo floodplain , Fishes -- Behavior
- Description: The Phongolo River floodplain in KwaZulu/Natal is a river-associated wetland which was subject to regular cycles of flooding in the past. The floods were associated with seasonal summer rainfall. Through the wet and dry cycles on the floodplain there was an alternation between the aquatic and terrestrial biomes. Many of the fishes on the floodplain are dependent on this cycle for their survival. The construction of the Pongolapoort Dam in 1969 has resulted in alterations to the timing, magnitudes and duration of the natural flooding events of the Phongolo River. This alteration has affected the fisheries. It is now necessary to simulate natural floods by artificial water releases from the dam. There are several demands on the water supply, so it has not always been possible to adhere to the natural flood regime. This necessitated the need for an integrated management programme to ensure the sustainability of the natural resources. A practical ecological model of the fishery was developed to determine an optimum flood release scenario for the floodplain. The relative abundances, distribution and species richness of the fishes were determined at various lakes and rivers on the floodplain. A community classification of the fishes was determined using TWINSPAN ordination. The potential yield of the fish at each site was calculated. Flood releases of varying magnitudes were simulated using Geographic Information Systems (GIS). This information was combined in a model which can be used by resource managers to estimate the percentage species compositions of fishes at each of the lakes, and to compare the actual harvest to the potential calculated sustainable yields of fishes for various flood release regimes. Subsistence agriculture and other beneficial ecological information can be incorporated into the model to determine the effect of different flood release options for the Phongolo floodplain.
- Full Text:
- Date Issued: 1996
- Authors: Weldrick, Sarah Katharine
- Date: 1996
- Subjects: Flood control -- Environmental aspects -- South Africa -- KwaZulu-Natal -- Pongolo floodplain , Fishes -- Behavior
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5258 , http://hdl.handle.net/10962/d1005102 , Flood control -- Environmental aspects -- South Africa -- KwaZulu-Natal -- Pongolo floodplain , Fishes -- Behavior
- Description: The Phongolo River floodplain in KwaZulu/Natal is a river-associated wetland which was subject to regular cycles of flooding in the past. The floods were associated with seasonal summer rainfall. Through the wet and dry cycles on the floodplain there was an alternation between the aquatic and terrestrial biomes. Many of the fishes on the floodplain are dependent on this cycle for their survival. The construction of the Pongolapoort Dam in 1969 has resulted in alterations to the timing, magnitudes and duration of the natural flooding events of the Phongolo River. This alteration has affected the fisheries. It is now necessary to simulate natural floods by artificial water releases from the dam. There are several demands on the water supply, so it has not always been possible to adhere to the natural flood regime. This necessitated the need for an integrated management programme to ensure the sustainability of the natural resources. A practical ecological model of the fishery was developed to determine an optimum flood release scenario for the floodplain. The relative abundances, distribution and species richness of the fishes were determined at various lakes and rivers on the floodplain. A community classification of the fishes was determined using TWINSPAN ordination. The potential yield of the fish at each site was calculated. Flood releases of varying magnitudes were simulated using Geographic Information Systems (GIS). This information was combined in a model which can be used by resource managers to estimate the percentage species compositions of fishes at each of the lakes, and to compare the actual harvest to the potential calculated sustainable yields of fishes for various flood release regimes. Subsistence agriculture and other beneficial ecological information can be incorporated into the model to determine the effect of different flood release options for the Phongolo floodplain.
- Full Text:
- Date Issued: 1996
The development of an electrochemical process for the production of para-substituted di-hydroxy benzenes
- Authors: Rautenbach, Daniel
- Date: 2005
- Subjects: Phenol , Benzene
- Language: English
- Type: Thesis , Doctoral , DTech (Science)
- Identifier: vital:10367 , http://hdl.handle.net/10948/159 , Phenol , Benzene
- Description: The project was concerned with the investigation of the electrochemical oxidation of various phenols, and to develop a viable reaction system for the production of the respective hydroquinones. Current production routes utilizing phenol as starting material have the limitations of using large amounts of acids, having to be stopped at low conversions and producing a mixture of the hydroquinones and catechols. Of the possible routes to the respective hydroquinones from the various phenols, the electrochemical oxidation of these phenols offers commercial and environmental advantages and hence formed the theme of the investigation. The synthetic possibilities proved to be more prevalent in a system when the electrochemical oxidation of these phenols was performed in an aqueous medium utilizing an organic co-solvent. Results obtained during this investigation made it possible to make certain predications about the mechanism taking place. This was found to depend on the anode material used for the oxidation. The results showed that the process developed for the electrochemical oxidation of these phenols, yields mainly the para-isomers of the respective hydroquinones and benzoquinones in good yields and selectivities, with fair current efficiencies and good mass balances at high conversions. For example: * Phenol (batch) 8 F: 345% current efficiency, 70% hydroquinone, 6% catechol, 9% benzoquinone, 9% phenol and 94 mass balance. * 2-Tert-butylphenol (flow) 10 F: 37% current efficiency, 65% hydroquinone, 33% benzoquinone, 2% phenol and 100% mass balance. * 2,6-Di-tert-butylphenol (flow) 11 F: 23% current efficiency, 92 % hydroquinone, 6% benzoquinone, 1% phenol and 99% mass balance. The developed electrochemical oxidation system offers the following advantages over previous and current methods: simplified isolation and extraction procedures, smaller amounts of acid usage, reasonably selective synthesis of the para-isomer and a less corrosive system all at high conversions.
- Full Text:
- Date Issued: 2005
- Authors: Rautenbach, Daniel
- Date: 2005
- Subjects: Phenol , Benzene
- Language: English
- Type: Thesis , Doctoral , DTech (Science)
- Identifier: vital:10367 , http://hdl.handle.net/10948/159 , Phenol , Benzene
- Description: The project was concerned with the investigation of the electrochemical oxidation of various phenols, and to develop a viable reaction system for the production of the respective hydroquinones. Current production routes utilizing phenol as starting material have the limitations of using large amounts of acids, having to be stopped at low conversions and producing a mixture of the hydroquinones and catechols. Of the possible routes to the respective hydroquinones from the various phenols, the electrochemical oxidation of these phenols offers commercial and environmental advantages and hence formed the theme of the investigation. The synthetic possibilities proved to be more prevalent in a system when the electrochemical oxidation of these phenols was performed in an aqueous medium utilizing an organic co-solvent. Results obtained during this investigation made it possible to make certain predications about the mechanism taking place. This was found to depend on the anode material used for the oxidation. The results showed that the process developed for the electrochemical oxidation of these phenols, yields mainly the para-isomers of the respective hydroquinones and benzoquinones in good yields and selectivities, with fair current efficiencies and good mass balances at high conversions. For example: * Phenol (batch) 8 F: 345% current efficiency, 70% hydroquinone, 6% catechol, 9% benzoquinone, 9% phenol and 94 mass balance. * 2-Tert-butylphenol (flow) 10 F: 37% current efficiency, 65% hydroquinone, 33% benzoquinone, 2% phenol and 100% mass balance. * 2,6-Di-tert-butylphenol (flow) 11 F: 23% current efficiency, 92 % hydroquinone, 6% benzoquinone, 1% phenol and 99% mass balance. The developed electrochemical oxidation system offers the following advantages over previous and current methods: simplified isolation and extraction procedures, smaller amounts of acid usage, reasonably selective synthesis of the para-isomer and a less corrosive system all at high conversions.
- Full Text:
- Date Issued: 2005
The development of an entrepreneurial management model to promote the survival and growth of family estate wine businesses in the South African wine industry
- Cullen, Margaret Diane Munro
- Authors: Cullen, Margaret Diane Munro
- Date: 2006
- Subjects: Family-owned business enterprises -- South Africa , Wine industry -- South Africa -- Management , Entrepreneurship
- Language: English
- Type: Thesis , Doctoral , DBA
- Identifier: vital:8766 , http://hdl.handle.net/10948/491 , http://hdl.handle.net/10948/d1011909 , Family-owned business enterprises -- South Africa , Wine industry -- South Africa -- Management , Entrepreneurship
- Description: The South African wine industry is polarised into the quantity-producing majority and the quality-conscious minority [Hughes, 2003]. The qualityproducing sector of the South African wine industry is dominated by family businesses. Research shows that there are approximately ninety familyowned wineries in South Africa. By international standards, South Africa is viewed as a quantity, not quality producing wine country, which will make it difficult to survive in an industry where quality is paramount for recognition. The ‘trailblazers’ of the international wine industry are family owned wineries [Robinson, 2000]. Twenty five percent of the 2003 five star South African wines were made by individuals or family wineries [Hughes, 2003], emphasising the growing importance of family wineries in the production of quality wines. It is important now, more than ever, with the industry opening up internationally, that survival of the family-owned wineries and their production of icon wines are promoted so that they can become flagship producers of the industry. The achievement of international status as a quality producing country, as well as building an industry based on the longevity of wine producing families, as well as a nation of wine lovers in South Africa should result.
- Full Text:
- Date Issued: 2006
- Authors: Cullen, Margaret Diane Munro
- Date: 2006
- Subjects: Family-owned business enterprises -- South Africa , Wine industry -- South Africa -- Management , Entrepreneurship
- Language: English
- Type: Thesis , Doctoral , DBA
- Identifier: vital:8766 , http://hdl.handle.net/10948/491 , http://hdl.handle.net/10948/d1011909 , Family-owned business enterprises -- South Africa , Wine industry -- South Africa -- Management , Entrepreneurship
- Description: The South African wine industry is polarised into the quantity-producing majority and the quality-conscious minority [Hughes, 2003]. The qualityproducing sector of the South African wine industry is dominated by family businesses. Research shows that there are approximately ninety familyowned wineries in South Africa. By international standards, South Africa is viewed as a quantity, not quality producing wine country, which will make it difficult to survive in an industry where quality is paramount for recognition. The ‘trailblazers’ of the international wine industry are family owned wineries [Robinson, 2000]. Twenty five percent of the 2003 five star South African wines were made by individuals or family wineries [Hughes, 2003], emphasising the growing importance of family wineries in the production of quality wines. It is important now, more than ever, with the industry opening up internationally, that survival of the family-owned wineries and their production of icon wines are promoted so that they can become flagship producers of the industry. The achievement of international status as a quality producing country, as well as building an industry based on the longevity of wine producing families, as well as a nation of wine lovers in South Africa should result.
- Full Text:
- Date Issued: 2006
The development of an immobilised-enzyme bioprobe for the detection of phenolic pollutants in water
- Authors: Russell, Ingrid Margaret
- Date: 1999
- Subjects: Pollutants -- Biodegradation , Pollutants , Chemical reactors , Membrane reactors , Fungi -- Biotechnology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4069 , http://hdl.handle.net/10962/d1006211 , Pollutants -- Biodegradation , Pollutants , Chemical reactors , Membrane reactors , Fungi -- Biotechnology
- Description: The possibility of developing an immobilised-enzyme bioprobe, based on mushroom polyphenol oxidase, for the purely biological detection and quantification of phenolic pollutants in water was investigated. Polyphenol oxidase catalyses the bioconversion of many phenolic compounds into quinone-related coloured products. Thus, in an immobilised form, the enzyme serves as a visible indicator of the presence and concentration of phenolic pollutants in water. The objective of this research was to develop a portable, disposable bioprobe incorporating polyphenol oxidase for this purpose. The intensity of the colour changes produced by the enzyme on reaction with p-cresol, p-chlorophenol and phenol was found to increase proportionally with increasing concentrations of these substrates in solution. Immobilisation of the enzyme on various supports did not appear to significantly affect the catalytic activity of the enzyme. The enzyme was immobilised by adsorption and cross-linking on polyethersulphone, nitrocellulose and nylon membranes with the production of various colour ranges on reaction with the phenolic substrates. The most successful immobilisation of the enzyme, in terms of quantity and distribution of enzyme immobilised and colour production, was obtained with the enzyme immobilised by adsorption on nylon membranes in the presence of 3-methyl-2-benzothiazolinone hydrazone (MBTH). The enzyme, immobilised using this method, produced ranges of maroon colours in phenolic solutions and orange colours in cresylic solutions. The colour intensities produced were found to increase proportionally with increasing substrate concentration after 5 minutes exposure to the substrates. The bioprobe had a broad substrate specificity and was sensitive to substrate concentrations down to 0.05 mg/L. The enzyme activity of the bioprobe was not significantly affected in a pH range from 4 to 10 and in a temperature range from 5-25⁰C. The bioprobe activity was not affected by various concentrations of salt and metal ions and the bioprobe was able to detect and semi-quantify phenolic substrates in industrial effluent samples. These features of the bioprobe indicate that the commercialisation of such a bioprobe is feasible and this technology has been patented (Patent No. SA 97/0227). , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 1999
- Authors: Russell, Ingrid Margaret
- Date: 1999
- Subjects: Pollutants -- Biodegradation , Pollutants , Chemical reactors , Membrane reactors , Fungi -- Biotechnology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4069 , http://hdl.handle.net/10962/d1006211 , Pollutants -- Biodegradation , Pollutants , Chemical reactors , Membrane reactors , Fungi -- Biotechnology
- Description: The possibility of developing an immobilised-enzyme bioprobe, based on mushroom polyphenol oxidase, for the purely biological detection and quantification of phenolic pollutants in water was investigated. Polyphenol oxidase catalyses the bioconversion of many phenolic compounds into quinone-related coloured products. Thus, in an immobilised form, the enzyme serves as a visible indicator of the presence and concentration of phenolic pollutants in water. The objective of this research was to develop a portable, disposable bioprobe incorporating polyphenol oxidase for this purpose. The intensity of the colour changes produced by the enzyme on reaction with p-cresol, p-chlorophenol and phenol was found to increase proportionally with increasing concentrations of these substrates in solution. Immobilisation of the enzyme on various supports did not appear to significantly affect the catalytic activity of the enzyme. The enzyme was immobilised by adsorption and cross-linking on polyethersulphone, nitrocellulose and nylon membranes with the production of various colour ranges on reaction with the phenolic substrates. The most successful immobilisation of the enzyme, in terms of quantity and distribution of enzyme immobilised and colour production, was obtained with the enzyme immobilised by adsorption on nylon membranes in the presence of 3-methyl-2-benzothiazolinone hydrazone (MBTH). The enzyme, immobilised using this method, produced ranges of maroon colours in phenolic solutions and orange colours in cresylic solutions. The colour intensities produced were found to increase proportionally with increasing substrate concentration after 5 minutes exposure to the substrates. The bioprobe had a broad substrate specificity and was sensitive to substrate concentrations down to 0.05 mg/L. The enzyme activity of the bioprobe was not significantly affected in a pH range from 4 to 10 and in a temperature range from 5-25⁰C. The bioprobe activity was not affected by various concentrations of salt and metal ions and the bioprobe was able to detect and semi-quantify phenolic substrates in industrial effluent samples. These features of the bioprobe indicate that the commercialisation of such a bioprobe is feasible and this technology has been patented (Patent No. SA 97/0227). , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 1999
The development of an improved coded-pulse, vertical-incidence ionosonde
- Authors: Cretchley, Brian Brind
- Date: 1979
- Subjects: Ionosondes Ionospheric sounds Computer simulation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5436 , http://hdl.handle.net/10962/d1001989
- Description: This thesis describes the theoretical development of a new ionospheric sounding system. The different types of ionosonde, their prime objectives, and their relative merits and demerits are discussed. The various types of code and their correlation functions are described. The essential requirements of the new system are listed, and suitable codes are found for it. Computer calculations and mathematical derivations demonstrate the (theoretical) suitability of these codes under all conditions. Essentials of the mode of operation of the system and details of its design are specified, and computer simulations are used to examine relevant aspects of its operation. Finally, since the construction of the system is not complete and results cannot therefore be presented, the present state of construction of the system is described
- Full Text:
- Date Issued: 1979
- Authors: Cretchley, Brian Brind
- Date: 1979
- Subjects: Ionosondes Ionospheric sounds Computer simulation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5436 , http://hdl.handle.net/10962/d1001989
- Description: This thesis describes the theoretical development of a new ionospheric sounding system. The different types of ionosonde, their prime objectives, and their relative merits and demerits are discussed. The various types of code and their correlation functions are described. The essential requirements of the new system are listed, and suitable codes are found for it. Computer calculations and mathematical derivations demonstrate the (theoretical) suitability of these codes under all conditions. Essentials of the mode of operation of the system and details of its design are specified, and computer simulations are used to examine relevant aspects of its operation. Finally, since the construction of the system is not complete and results cannot therefore be presented, the present state of construction of the system is described
- Full Text:
- Date Issued: 1979
The development of an in vitro system for the production of drug metabolites using microsomal enzymes from bovine liver
- Authors: Morrison, Roxanne
- Date: 2011
- Subjects: Drugs -- Metabolism , Xenobiotics -- Metabolism , Metabolites , Drugs -- Testing , Toxicity testing -- In vitro , Doping in horse racing -- Control -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4087 , http://hdl.handle.net/10962/d1007698 , Drugs -- Metabolism , Xenobiotics -- Metabolism , Metabolites , Drugs -- Testing , Toxicity testing -- In vitro , Doping in horse racing -- Control -- Research
- Description: Drug metabolism is a specialised subset of xenobiotic metabolism, pertaining to the breakdown and elimination of pharmaceutical drugs. The enzymes involved in these pathways are the cytochrome P450 family of isozymes. Metabolism is an important factor in determining the pharmacological effects of drugs. The main aim of this study was to develop a system whereby the major metabolites of drugs can be produced in vitro. An in vitro system was developed and optimised using commercially prepared microsomes from rat liver and coumarin (by monitoring its conversion to 7-hydroxycoumarin) as a model. The optimum running conditions for the incubations were 50 μM coumarin, 50 μg protein/ml microsomes, 1 mM NADP⁺, 5 mM G6P and 1U/ml G6PDH incubated for 30 minutes at 38℃. The HPLC method for the detection of coumarin and 7-hydroxycoumarin was also validated with respect to linearity, reproducibility, precision, accuracy and lower limits of detection and quantification. The system developed was then tested using microsomes prepared from fresh bovine liver on these ten drugs of interest in doping control in horse racing: diazepam, nordiazepam, oxazepam, promazine, acepromazine, chlorpromazine, morphine, codeine, etoricoxib and lumiracoxib. The bovine liver microsomes were prepared using differential centrifugation and had activity on a par with the commercial preparations. This in vitro system metabolised the drugs and produced both phase I and II metabolites, similar to those observed in humans and horses in vivo. For example, the major metabolites of the benzodiazepine drug, diazepam, nordiazepam, temazepam and oxazepam as well as the glucuronidated phase II products were all found after incubations with the bovine liver microsomes. The metabolism of the drugs was also investigated in silico using the computational procedure, MetaSite. MetaSite was able to successfully predict known metabolites for most of the drugs studied. Differences were observed from the in vitro incubations and this is most likely due to MetaSite using only human cytochrome P450s for analysis.
- Full Text:
- Date Issued: 2011
- Authors: Morrison, Roxanne
- Date: 2011
- Subjects: Drugs -- Metabolism , Xenobiotics -- Metabolism , Metabolites , Drugs -- Testing , Toxicity testing -- In vitro , Doping in horse racing -- Control -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4087 , http://hdl.handle.net/10962/d1007698 , Drugs -- Metabolism , Xenobiotics -- Metabolism , Metabolites , Drugs -- Testing , Toxicity testing -- In vitro , Doping in horse racing -- Control -- Research
- Description: Drug metabolism is a specialised subset of xenobiotic metabolism, pertaining to the breakdown and elimination of pharmaceutical drugs. The enzymes involved in these pathways are the cytochrome P450 family of isozymes. Metabolism is an important factor in determining the pharmacological effects of drugs. The main aim of this study was to develop a system whereby the major metabolites of drugs can be produced in vitro. An in vitro system was developed and optimised using commercially prepared microsomes from rat liver and coumarin (by monitoring its conversion to 7-hydroxycoumarin) as a model. The optimum running conditions for the incubations were 50 μM coumarin, 50 μg protein/ml microsomes, 1 mM NADP⁺, 5 mM G6P and 1U/ml G6PDH incubated for 30 minutes at 38℃. The HPLC method for the detection of coumarin and 7-hydroxycoumarin was also validated with respect to linearity, reproducibility, precision, accuracy and lower limits of detection and quantification. The system developed was then tested using microsomes prepared from fresh bovine liver on these ten drugs of interest in doping control in horse racing: diazepam, nordiazepam, oxazepam, promazine, acepromazine, chlorpromazine, morphine, codeine, etoricoxib and lumiracoxib. The bovine liver microsomes were prepared using differential centrifugation and had activity on a par with the commercial preparations. This in vitro system metabolised the drugs and produced both phase I and II metabolites, similar to those observed in humans and horses in vivo. For example, the major metabolites of the benzodiazepine drug, diazepam, nordiazepam, temazepam and oxazepam as well as the glucuronidated phase II products were all found after incubations with the bovine liver microsomes. The metabolism of the drugs was also investigated in silico using the computational procedure, MetaSite. MetaSite was able to successfully predict known metabolites for most of the drugs studied. Differences were observed from the in vitro incubations and this is most likely due to MetaSite using only human cytochrome P450s for analysis.
- Full Text:
- Date Issued: 2011
The development of an in-service training programme for mathematics teachers on the development and use of resource materials in black schools at the standard six-seven level
- Authors: Jiya, M A Yaliwe
- Date: 1984
- Subjects: Mathematics teachers -- In-service training -- South Africa Black people -- Education -- South Africa Mathematics -- Study and teaching (Secondary) -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1875 , http://hdl.handle.net/10962/d1005634
- Full Text:
- Date Issued: 1984
- Authors: Jiya, M A Yaliwe
- Date: 1984
- Subjects: Mathematics teachers -- In-service training -- South Africa Black people -- Education -- South Africa Mathematics -- Study and teaching (Secondary) -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1875 , http://hdl.handle.net/10962/d1005634
- Full Text:
- Date Issued: 1984
The development of an instrument to measure intrapreneurship: entrepreneurship within the corporate setting
- Authors: Hill, Marguerite Elizabeth
- Date: 2003
- Subjects: Entrepreneurship , Psychology, Industrial , Organizational change
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2991 , http://hdl.handle.net/10962/d1002500 , Entrepreneurship , Psychology, Industrial , Organizational change
- Description: “Intrapreneurship is not a choice, it is the only survival attitude” (Pinchot, 2000, p.75). In 1985 Pinchot coined the term ‘intrapreneurship’, short for intra-corporate entrepreneurship, which describes the practice of entrepreneurship within organisations. Intrapreneurship is increasingly becoming a term used in the business world to describe organisations that are willing to pursue opportunities, initiate actions, and emphasise new, innovative products or services. Due to the dynamic nature of modern organisations, it is imperative that organisations and their managers remain receptive to new ideas, approaches and attitudes. It is therefore the belief that rapid and cost-effective innovation is the primary source of lasting competitive advantage in the twenty-first century, leaving organisations no alternative but to become intrapreneurial or cease to exist. This thesis focuses on this need and examines ways in which intrapreneurship can be measured in organisations in order to provide a benchmark for further organisational development. A questionnaire (known as the Intrapreneurial Intensity Index) was designed and distributed to a sample of 500 employees working in large South African organisations, which classified themselves as ‘forward-thinking’ and aimed for an intrapreneurial ‘type of thinking’. The results obtained from these questionnaires underwent item analysis, after which the questionnaire was redesigned in an electronic format. A pilot case study was then conducted in order to test the reliability of the instrument. Finally the questionnaire was redistributed to a sample of six organisations that are viewed as being ‘intrapreneurial’ and two that are regarded as being ‘non-intrapreneurial’. The data from this sample was used to test the validity of the Intrapreneurial Intensity Index and to demonstrate its application. This study resulted in an instrument that can be used to ascertain the intensity of intrapreneurship present in a large organisation. Specifically, this instrument can provide an overall view of the organisation’s intrapreneurial ability, as well as identify the specific areas in the organisation that require change or modification in order to become more intrapreneurial. This instrument provides a valuable means of identifying areas in need of organisational change, by determining an organisation’s intrapreneurial properties in the organisation’s core areas.
- Full Text:
- Date Issued: 2003
- Authors: Hill, Marguerite Elizabeth
- Date: 2003
- Subjects: Entrepreneurship , Psychology, Industrial , Organizational change
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2991 , http://hdl.handle.net/10962/d1002500 , Entrepreneurship , Psychology, Industrial , Organizational change
- Description: “Intrapreneurship is not a choice, it is the only survival attitude” (Pinchot, 2000, p.75). In 1985 Pinchot coined the term ‘intrapreneurship’, short for intra-corporate entrepreneurship, which describes the practice of entrepreneurship within organisations. Intrapreneurship is increasingly becoming a term used in the business world to describe organisations that are willing to pursue opportunities, initiate actions, and emphasise new, innovative products or services. Due to the dynamic nature of modern organisations, it is imperative that organisations and their managers remain receptive to new ideas, approaches and attitudes. It is therefore the belief that rapid and cost-effective innovation is the primary source of lasting competitive advantage in the twenty-first century, leaving organisations no alternative but to become intrapreneurial or cease to exist. This thesis focuses on this need and examines ways in which intrapreneurship can be measured in organisations in order to provide a benchmark for further organisational development. A questionnaire (known as the Intrapreneurial Intensity Index) was designed and distributed to a sample of 500 employees working in large South African organisations, which classified themselves as ‘forward-thinking’ and aimed for an intrapreneurial ‘type of thinking’. The results obtained from these questionnaires underwent item analysis, after which the questionnaire was redesigned in an electronic format. A pilot case study was then conducted in order to test the reliability of the instrument. Finally the questionnaire was redistributed to a sample of six organisations that are viewed as being ‘intrapreneurial’ and two that are regarded as being ‘non-intrapreneurial’. The data from this sample was used to test the validity of the Intrapreneurial Intensity Index and to demonstrate its application. This study resulted in an instrument that can be used to ascertain the intensity of intrapreneurship present in a large organisation. Specifically, this instrument can provide an overall view of the organisation’s intrapreneurial ability, as well as identify the specific areas in the organisation that require change or modification in order to become more intrapreneurial. This instrument provides a valuable means of identifying areas in need of organisational change, by determining an organisation’s intrapreneurial properties in the organisation’s core areas.
- Full Text:
- Date Issued: 2003
The development of an integrated management model for occupational health and safety in medical institutions
- Authors: Du Toit, Willem Johannes
- Date: 2005
- Subjects: Industrial safety -- South Africa -- Management , Industrial hygiene -- South Africa -- Management , Health facilities -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8551 , http://hdl.handle.net/10948/1300 , Industrial safety -- South Africa -- Management , Industrial hygiene -- South Africa -- Management , Health facilities -- South Africa
- Description: Health and safety management forms part of the overall risk management of medical institutions, and deals with the responsibility of an organisation to provide a risk free environment for all who are exposed to the activities of such medical institutions. Affected people include health care workers, contractors, visitors, and patients. Medical institutions, and hospitals specifically, are uniquely distinct from other industries in that they employ highly skilled staff with specific specialised knowledge. These institutions are also increasingly making use of complex technology that requires specialist staff to operate medical machines and equipment. These specific aspects are accounted for in this research. The overall purpose of this research is to determine the need for an alternative approach to the management of health and safety in medical institutions. An appropriate model will be developed that can be integrated into the existing health and safety management system. The research methodology for this study comprises the following steps: Firstly, the health and safety environment was researched in relation to all stakeholders, external and internal, that are affected by medical institutions’ activities. The effect of these activities, and how it influences health and safety management, was evaluated in a South African context. Secondly, the overall risk management approach of medical institutions and the effect of organisational culture were researched to determine the effect on health and safety performance. Thirdly, a questionnaire was sent to selected staff of five hospitals in the Eastern and Western Cape to determine their perception and experience of health and safety management. Quantitative data on incidents in Netcare Hospitals were obtained, and a comparison of the questionnaire studies was done to determine the need for a health and safety model. The final step of this study entailed the development of a health and safety model using legislative requirements and the needs identified in the research. A proposal is made to integrate specialist functions and departments into the existing health and safety management system, in order to strengthen the managerial capabilities of such a system. The importance of improving the safety and compliance culture is indicated.
- Full Text:
- Date Issued: 2005
- Authors: Du Toit, Willem Johannes
- Date: 2005
- Subjects: Industrial safety -- South Africa -- Management , Industrial hygiene -- South Africa -- Management , Health facilities -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8551 , http://hdl.handle.net/10948/1300 , Industrial safety -- South Africa -- Management , Industrial hygiene -- South Africa -- Management , Health facilities -- South Africa
- Description: Health and safety management forms part of the overall risk management of medical institutions, and deals with the responsibility of an organisation to provide a risk free environment for all who are exposed to the activities of such medical institutions. Affected people include health care workers, contractors, visitors, and patients. Medical institutions, and hospitals specifically, are uniquely distinct from other industries in that they employ highly skilled staff with specific specialised knowledge. These institutions are also increasingly making use of complex technology that requires specialist staff to operate medical machines and equipment. These specific aspects are accounted for in this research. The overall purpose of this research is to determine the need for an alternative approach to the management of health and safety in medical institutions. An appropriate model will be developed that can be integrated into the existing health and safety management system. The research methodology for this study comprises the following steps: Firstly, the health and safety environment was researched in relation to all stakeholders, external and internal, that are affected by medical institutions’ activities. The effect of these activities, and how it influences health and safety management, was evaluated in a South African context. Secondly, the overall risk management approach of medical institutions and the effect of organisational culture were researched to determine the effect on health and safety performance. Thirdly, a questionnaire was sent to selected staff of five hospitals in the Eastern and Western Cape to determine their perception and experience of health and safety management. Quantitative data on incidents in Netcare Hospitals were obtained, and a comparison of the questionnaire studies was done to determine the need for a health and safety model. The final step of this study entailed the development of a health and safety model using legislative requirements and the needs identified in the research. A proposal is made to integrate specialist functions and departments into the existing health and safety management system, in order to strengthen the managerial capabilities of such a system. The importance of improving the safety and compliance culture is indicated.
- Full Text:
- Date Issued: 2005
The development of an integrated model for the implementation of a product data management system at Delta Motor Corporation
- Authors: Stroud, Trevor
- Date: 2003
- Subjects: Computer integrated manufacturing systems , Automobile industry and trade -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10873 , http://hdl.handle.net/10948/224 , Computer integrated manufacturing systems , Automobile industry and trade -- South Africa -- Port Elizabeth
- Description: Information technology in mature organisations is viewed as an enabler of teams working together in the product development process. Technology is no longer pursued as an end in itself, but for its contribution to cost control, product quality, and most importantly, time to profit. The focus of this research is the analysis of methodologies used to implement the Teamcenter Engineering Product Data Management (PDM) system at Delta Motor Corporation, which manages all of Delta’s CAD data. The main problem of this research is as follows: How can Delta Motor Corporation successfully implement the “Teamcentre Engineering” Product Data Management System? The main problem will be broken down into three distinct parts, namely the developing of a best practice process, analysing Delta’s implementation and making recommendations for improvement. The literature survey provides the basis for developing a best-practice process, which serves as a benchmark against which to evaluate the methodology used by Delta. Interviews were conducted with selected personnel who were involved in the implementation, and Tesch’s model for content analysis used to analyse the responses. The implementation process of Teamcenter Engineering at Delta was conducted in three phases and only the first was completed at the time of writing this research paper. For this reason, analysis revolves around the first phase of implementation, which was limited to the drawing office, while recommendations are made for the implementation of phase two and three, which roll-out this system to the rest of Delta and it’s supplier base.
- Full Text:
- Date Issued: 2003
- Authors: Stroud, Trevor
- Date: 2003
- Subjects: Computer integrated manufacturing systems , Automobile industry and trade -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10873 , http://hdl.handle.net/10948/224 , Computer integrated manufacturing systems , Automobile industry and trade -- South Africa -- Port Elizabeth
- Description: Information technology in mature organisations is viewed as an enabler of teams working together in the product development process. Technology is no longer pursued as an end in itself, but for its contribution to cost control, product quality, and most importantly, time to profit. The focus of this research is the analysis of methodologies used to implement the Teamcenter Engineering Product Data Management (PDM) system at Delta Motor Corporation, which manages all of Delta’s CAD data. The main problem of this research is as follows: How can Delta Motor Corporation successfully implement the “Teamcentre Engineering” Product Data Management System? The main problem will be broken down into three distinct parts, namely the developing of a best practice process, analysing Delta’s implementation and making recommendations for improvement. The literature survey provides the basis for developing a best-practice process, which serves as a benchmark against which to evaluate the methodology used by Delta. Interviews were conducted with selected personnel who were involved in the implementation, and Tesch’s model for content analysis used to analyse the responses. The implementation process of Teamcenter Engineering at Delta was conducted in three phases and only the first was completed at the time of writing this research paper. For this reason, analysis revolves around the first phase of implementation, which was limited to the drawing office, while recommendations are made for the implementation of phase two and three, which roll-out this system to the rest of Delta and it’s supplier base.
- Full Text:
- Date Issued: 2003
The development of an integrated value chain cost reduction methodology
- Welman, Abraham Jacobus Frederik
- Authors: Welman, Abraham Jacobus Frederik
- Date: 2013
- Subjects: Corporations -- Finance -- Management , Manufacturing industries -- Cost control , Industrial procurement
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:8775 , http://hdl.handle.net/10948/d1012954
- Description: The reason for the existence of any company is to make a profit, which means increasing turnover and keeping costs as low as possible. Optimisation of the Value Chain and Procurement were identified as the two largest contributors when one needs to improve the bottom line of any company. The purpose of this research was to develop an integrated Value Chain and Procurement cost reduction methodology and system specifications for a software solution which captures, tracks and accurately reports the impact of the improvement initiatives. The main research question was structured as follows: What should the specifications of a software solution be that will integrate the cost reduction processes of the Value Chain and of Procurement, in a manner that will ensure maximum sustainable bottom-line savings for companies in the manufacturing or service industries? The objective was to define the key phases in the Value Chain and Procurement cost reduction process and to determine how and where they integrate. It is important to note that according the literature review and the survey, both the Value Chain and Procurement cost reduction processes consist of seven phases. The phases of the Value Chain cost reduction process were: Phase 1: Budget/ABC costing and data analysis; Phase 2: Generate ideas; Phase 3: Evaluate and approve ideas; Phase 4: Implementation planning and approval; Phase 5: Development of project (idea) specific KPI's; Phase 6: Implementation of ideas; Phase 7: Track and report savings. The phases of the Procurement (Strategic Sourcing) cost reduction process were: Phase 1: Team selection/data collection/spend analysis/work plan development Phase 2: Access requirements/internal and external analysis; Phase 3: Develop strategy/shape value proposition; Phase 4: Screen suppliers, issue RFI/P/Q, implementation planning; Phase 5: Conduct commercial event/negotiate/finalise contract; Phase 6: Implement contract; Phase 7: Contract management/track and reporting. The above two cost reduction processes integrate at each phase of the respective processes and should thus be implemented at the same time due to their interdependencies. Based on the findings of the research it was clear that an integrated Value Chain and Procurement cost reduction process alone is not going to solve the cost reduction problems of companies. It is essential for the successful implementation of the integrated cost reduction process to develop skills and knowledgeable resources to implement the integrated cost reduction process, improve collaboration between the Value Chain and Procurement, and to implement a system to track and report performance during implementation. Further research should include how to adapt the current company processes, structures, procedures and systems in order to gain maximum benefit from the implementation of an integrated cost reduction process. The integrated Value Chain and Procurement cost reduction process, supported by a software system, should improve the success of cost reduction projects in companies. It is, however, important to note that the application of the methodology will vary between industries and that service-related industries might put more emphasis on Procurement cost reduction, while the manufacturing industries might place a bigger emphasis on cost reduction in operations. In conclusion, irrespective of the industries, it is evident that this methodology will enhance the cost reduction results previously obtained from similar efforts.
- Full Text:
- Date Issued: 2013
- Authors: Welman, Abraham Jacobus Frederik
- Date: 2013
- Subjects: Corporations -- Finance -- Management , Manufacturing industries -- Cost control , Industrial procurement
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:8775 , http://hdl.handle.net/10948/d1012954
- Description: The reason for the existence of any company is to make a profit, which means increasing turnover and keeping costs as low as possible. Optimisation of the Value Chain and Procurement were identified as the two largest contributors when one needs to improve the bottom line of any company. The purpose of this research was to develop an integrated Value Chain and Procurement cost reduction methodology and system specifications for a software solution which captures, tracks and accurately reports the impact of the improvement initiatives. The main research question was structured as follows: What should the specifications of a software solution be that will integrate the cost reduction processes of the Value Chain and of Procurement, in a manner that will ensure maximum sustainable bottom-line savings for companies in the manufacturing or service industries? The objective was to define the key phases in the Value Chain and Procurement cost reduction process and to determine how and where they integrate. It is important to note that according the literature review and the survey, both the Value Chain and Procurement cost reduction processes consist of seven phases. The phases of the Value Chain cost reduction process were: Phase 1: Budget/ABC costing and data analysis; Phase 2: Generate ideas; Phase 3: Evaluate and approve ideas; Phase 4: Implementation planning and approval; Phase 5: Development of project (idea) specific KPI's; Phase 6: Implementation of ideas; Phase 7: Track and report savings. The phases of the Procurement (Strategic Sourcing) cost reduction process were: Phase 1: Team selection/data collection/spend analysis/work plan development Phase 2: Access requirements/internal and external analysis; Phase 3: Develop strategy/shape value proposition; Phase 4: Screen suppliers, issue RFI/P/Q, implementation planning; Phase 5: Conduct commercial event/negotiate/finalise contract; Phase 6: Implement contract; Phase 7: Contract management/track and reporting. The above two cost reduction processes integrate at each phase of the respective processes and should thus be implemented at the same time due to their interdependencies. Based on the findings of the research it was clear that an integrated Value Chain and Procurement cost reduction process alone is not going to solve the cost reduction problems of companies. It is essential for the successful implementation of the integrated cost reduction process to develop skills and knowledgeable resources to implement the integrated cost reduction process, improve collaboration between the Value Chain and Procurement, and to implement a system to track and report performance during implementation. Further research should include how to adapt the current company processes, structures, procedures and systems in order to gain maximum benefit from the implementation of an integrated cost reduction process. The integrated Value Chain and Procurement cost reduction process, supported by a software system, should improve the success of cost reduction projects in companies. It is, however, important to note that the application of the methodology will vary between industries and that service-related industries might put more emphasis on Procurement cost reduction, while the manufacturing industries might place a bigger emphasis on cost reduction in operations. In conclusion, irrespective of the industries, it is evident that this methodology will enhance the cost reduction results previously obtained from similar efforts.
- Full Text:
- Date Issued: 2013
The development of an ionospheric storm-time index for the South African region
- Authors: Tshisaphungo, Mpho
- Date: 2021-04
- Subjects: Ionospheric storms -- South Africa , Global Positioning System , Neural networks (Computer science) , Regression analysis , Ionosondes , Auroral electrojet , Geomagnetic indexes , Magnetic storms -- South Africa
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/178409 , vital:42937 , 10.21504/10962/178409
- Description: This thesis presents the development of a regional ionospheric storm-time model which forms the foundation of an index to provide a quick view of the ionospheric storm effects over South African mid-latitude region. The model is based on the foF2 measurements from four South African ionosonde stations. The data coverage for the model development over Grahamstown (33.3◦S, 26.5◦E), Hermanus (34.42◦S, 19.22◦E), Louisvale (28.50◦S, 21.20◦E), and Madimbo (22.39◦S, 30.88◦E) is 1996-2016, 2009-2016, 2000-2016, and 2000-2016 respectively. Data from the Global Positioning System (GPS) and radio occultation (RO) technique were used during validation. As the measure of either positive or negative storm effect, the variation of the critical frequency of the F2 layer (foF2) from the monthly median values (denoted as _foF2) is modeled. The modeling of _foF2 is based on only storm time data with the criteria of Dst 6 -50 nT and Kp > 4. The modeling methods used in the study were artificial neural network (ANN), linear regression (LR) and polynomial functions. The approach taken was to first test the modeling techniques on a single station before expanding the study to cover the regional aspect. The single station modeling was developed based on ionosonde data over Grahamstown. The inputs for the model which related to seasonal variation, diurnal variation, geomagnetic activity and solar activity were considered. For the geomagnetic activity, three indices namely; the symmetric disturbance in the horizontal component of the Earth’s magnetic field (SYM − H), the Auroral Electrojet (AE) index and local geomagnetic index A, were included as inputs. The performance of a single station model revealed that, of the three geomagnetic indices, SYM − H index has the largest contribution of 41% and 54% based on ANN and LR techniques respectively. The average correlation coefficients (R) for both ANN and LR models was 0.8, when validated during the selected storms falling within the period of model development. When validated using storms that fall outside the period of model development, the model gave R values of 0.6 and 0.5 for ANN and LR respectively. In addition, the GPS total electron content (TEC) derived measurements were used to estimate foF2 data. This is because there are more GPS receivers than ionosonde locations and the utilisation of this data increases the spatial coverage of the regional model. The estimation of foF2 from GPS TEC was done at GPS-ionosonde co-locations using polynomial functions. The average R values of 0.69 and 0.65 were obtained between actual and derived _foF2 over the co-locations and other GPS stations respectively. Validation of GPS TEC derived foF2 with RO data over regions out of ionospheric pierce points coverage with respect to ionosonde locations gave R greater than 0.9 for the selected storm period of 4-8 August 2011. The regional storm-time model was then developed based on the ANN technique using the four South African ionosonde stations. The maximum and minimum R values of 0.6 and 0.5 were obtained over ionosonde and GPS locations respectively. This model forms the basis towards the regional ionospheric storm-time index. , Thesis (PhD) -- Faculty of Science, Physics and Electronics, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Tshisaphungo, Mpho
- Date: 2021-04
- Subjects: Ionospheric storms -- South Africa , Global Positioning System , Neural networks (Computer science) , Regression analysis , Ionosondes , Auroral electrojet , Geomagnetic indexes , Magnetic storms -- South Africa
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/178409 , vital:42937 , 10.21504/10962/178409
- Description: This thesis presents the development of a regional ionospheric storm-time model which forms the foundation of an index to provide a quick view of the ionospheric storm effects over South African mid-latitude region. The model is based on the foF2 measurements from four South African ionosonde stations. The data coverage for the model development over Grahamstown (33.3◦S, 26.5◦E), Hermanus (34.42◦S, 19.22◦E), Louisvale (28.50◦S, 21.20◦E), and Madimbo (22.39◦S, 30.88◦E) is 1996-2016, 2009-2016, 2000-2016, and 2000-2016 respectively. Data from the Global Positioning System (GPS) and radio occultation (RO) technique were used during validation. As the measure of either positive or negative storm effect, the variation of the critical frequency of the F2 layer (foF2) from the monthly median values (denoted as _foF2) is modeled. The modeling of _foF2 is based on only storm time data with the criteria of Dst 6 -50 nT and Kp > 4. The modeling methods used in the study were artificial neural network (ANN), linear regression (LR) and polynomial functions. The approach taken was to first test the modeling techniques on a single station before expanding the study to cover the regional aspect. The single station modeling was developed based on ionosonde data over Grahamstown. The inputs for the model which related to seasonal variation, diurnal variation, geomagnetic activity and solar activity were considered. For the geomagnetic activity, three indices namely; the symmetric disturbance in the horizontal component of the Earth’s magnetic field (SYM − H), the Auroral Electrojet (AE) index and local geomagnetic index A, were included as inputs. The performance of a single station model revealed that, of the three geomagnetic indices, SYM − H index has the largest contribution of 41% and 54% based on ANN and LR techniques respectively. The average correlation coefficients (R) for both ANN and LR models was 0.8, when validated during the selected storms falling within the period of model development. When validated using storms that fall outside the period of model development, the model gave R values of 0.6 and 0.5 for ANN and LR respectively. In addition, the GPS total electron content (TEC) derived measurements were used to estimate foF2 data. This is because there are more GPS receivers than ionosonde locations and the utilisation of this data increases the spatial coverage of the regional model. The estimation of foF2 from GPS TEC was done at GPS-ionosonde co-locations using polynomial functions. The average R values of 0.69 and 0.65 were obtained between actual and derived _foF2 over the co-locations and other GPS stations respectively. Validation of GPS TEC derived foF2 with RO data over regions out of ionospheric pierce points coverage with respect to ionosonde locations gave R greater than 0.9 for the selected storm period of 4-8 August 2011. The regional storm-time model was then developed based on the ANN technique using the four South African ionosonde stations. The maximum and minimum R values of 0.6 and 0.5 were obtained over ionosonde and GPS locations respectively. This model forms the basis towards the regional ionospheric storm-time index. , Thesis (PhD) -- Faculty of Science, Physics and Electronics, 2021
- Full Text:
- Date Issued: 2021-04
The development of an operations strategy for Eissmann South Africa that addresses market requirements and the needs of its customers
- Authors: Richards, Scott
- Date: 2002
- Subjects: Production management -- South Africa , Eissmmann South Africa (Firm) Customer services , Customer services -- Management
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10899 , http://hdl.handle.net/10948/88 , Production management -- South Africa , Eissmmann South Africa (Firm) Customer services , Customer services -- Management
- Description: With global competition becoming a key concept in the majority of companies worldwide, it is necessary for organisations to develop operations strategies that enable them to meet their customers‘ needs. Organisations will never be capable of reaching future goals without their customers. For this reason it is imperative for organisations to identify what competitive factors are required by the market, and which performance objectives are needed in order to increase the competitiveness of the organisation. In this research, Chapters 1 and 2 were used to identify the main and subproblems of the research, to delimit the research and to provide literature background to operations strategies and related operations topics. The empirical study in Chapter 3 was used to gather information pertaining to the specific requirements of ESA’s customers, and the operations performanceof ESA. Chapter 4 was used to analyse the data gathered from the empirical study. From this analysis it was possible for the researcher to identify the specific requirements of ESA’s customers and the operations performance of ESA. Chapter 5 was used to provide recommendations to bridge the performance gap between the customer requirements and the operations performance of ESA. By effectively implementing all of the recommendations suggested in this research, ESA will be able to improve its operation performance and meet the specific requirements of its market and its customers.
- Full Text:
- Date Issued: 2002
- Authors: Richards, Scott
- Date: 2002
- Subjects: Production management -- South Africa , Eissmmann South Africa (Firm) Customer services , Customer services -- Management
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10899 , http://hdl.handle.net/10948/88 , Production management -- South Africa , Eissmmann South Africa (Firm) Customer services , Customer services -- Management
- Description: With global competition becoming a key concept in the majority of companies worldwide, it is necessary for organisations to develop operations strategies that enable them to meet their customers‘ needs. Organisations will never be capable of reaching future goals without their customers. For this reason it is imperative for organisations to identify what competitive factors are required by the market, and which performance objectives are needed in order to increase the competitiveness of the organisation. In this research, Chapters 1 and 2 were used to identify the main and subproblems of the research, to delimit the research and to provide literature background to operations strategies and related operations topics. The empirical study in Chapter 3 was used to gather information pertaining to the specific requirements of ESA’s customers, and the operations performanceof ESA. Chapter 4 was used to analyse the data gathered from the empirical study. From this analysis it was possible for the researcher to identify the specific requirements of ESA’s customers and the operations performance of ESA. Chapter 5 was used to provide recommendations to bridge the performance gap between the customer requirements and the operations performance of ESA. By effectively implementing all of the recommendations suggested in this research, ESA will be able to improve its operation performance and meet the specific requirements of its market and its customers.
- Full Text:
- Date Issued: 2002
The development of an optimised decision based methodology for the replacement timing of frontline equipment utilised within the quarrying industry
- Authors: Basson, Kenneth Mervyn
- Date: 2018
- Subjects: Decision making , Industrial equipment Industrial equipment -- Maintenance and repair
- Language: English
- Type: Thesis , Doctoral , DBA
- Identifier: http://hdl.handle.net/10948/23647 , vital:30592
- Description: At present, frontline equipment employed at B&E International, and operating within the quarrying sector is typically replaced as soon as the operating expenses are deemed to be excessive. From a capital budgeting perspective, the trigger for signalling the replacement of equipment occurs when prescribed operating cost performance metrics are violated. In some instances, a further consideration for motivating the replacement of equipment is when the perception arises that the nonavailability of the equipment employed, results in financial losses being incurred by a company. It can therefore be argued that the current equipment replacement timing methodological approach adopted at B&E International is suboptimal in nature. The situation is further aggravated by the fact that in many instances, escalation of commitment manifests itself whereby unnecessary capital is repeatedly invested in order to extend the life of an asset resulting in a situation occurring whereby the required level of investment return is not achieved. In the event of these situations arising, the decision to replace an asset is prolonged as a result of the suboptimal investment decisions being made. The primary focus of this study is to provide a methodological equipment replacement framework that is based upon sound capital budgeting fundamentals. A comprehensive literature review of capital budgeting approaches that specifically focus on the optimal replacement timing of frontline quarrying equipment, did not yield any relevant studies that have been undertaken in this regard. This study did however investigate contemporary equipment replacement approaches based upon a capital budgeting paradigm and highlighted their respective limitations. Convincing evidence obtained, indicated that the most widely accepted method of identifying the optimal replacement timing of equipment occurs when the economic life of the asset is attained. This in itself would therefore infer that a cost minimisation approach is the most pervasive methodological approach adopted in order to identify the optimal replacement timing of equipment. When considering capital investment based decisions, it was found that the discounted cash flow based methodologies are the most widely used and accepted approach applied in the mining industry. Notwithstanding this, one major caveat manifests itself in that when considering the optimal replacement timing of front line equipment within the quarrying industry, the inclusion of uncertainty, flexibility and the associated financial risks was not evident. In order to model these effects, a probabilistic Net Present Value (NPV) approach was adopted and the required Discounted Cash Flow (DCF) models were constructed. Given the uncertainty of the expected cumulative R&M profiles for the asset classes constituting this study, an extensive statistical analysis was carried out in order to establish the required predictive Repair and Maintenance (R&M) models required for the DCF analysis by means of regression analysis. Further regression analyses were conducted in order to model the overall availability and utilisation metrics for the respective asset classes included in this study. The consequence of incurring downtime was investigated and the resultant DCF analysis yielded a significant impact on the Free Cash Flow (FCF) generated by the respective assets. The magnitude of the incurred consequential financial losses incurred as a result of the respective downtime was found to be significant when considering frontline equipment. In order to model the effect of, and the extent to which, the respective independent variables influence the static NPV outcome, a sensitivity analysis was performed. From this, the influence of the independent variables constituting the NPV model employed in this study, were observed. A Real Options Analysis (ROA) approach was initially employed in order to model the effects of FCF uncertainty and the results of carrying out this analysis indicated a minimal influence on the static NPV model referred to earlier. It was therefore concluded that from an equipment replacement timing perspective, the ROA approach did not provide a robust and accurate representation of the probabilistic NPV outcomes anticipated. In order to address these perceived shortcomings, an Monte Carlo Simulation (MCS) model was constructed and the requisite probability distribution functions representing the most influential independent variables determined from the sensitivity analysis were identified and subsequently analysed. The results of the MCS analysis yielded the expected NPV outcomes that were found to be far more conservative compared to the static NPV outcomes referred to previously. Furthermore, the concluding findings of this study indicate that in order to estimate the optimal time to dispose of an asset, a static NPV analysis must first be modelled and thereafter a probabilistic NPV analysis. The respective uncertainty aspects over the lifespan of the assets should be identified to be incorporated into the MCS model. This methodological approach therefore opposes the use of a strictly deterministic based approach and rather predicates the use of a probabilistic NPV based framework. This study further concluded that traditional DCF approaches fail to consider management flexibility in terms of adapting to uncertainty and to also reduce the possibility of “escalation of commitment” occurring as a result of sub-optimal equipment replacement timing decisions by management. The use and acceptance of the traditional DCF approaches are acknowledged, but in order to develop an equipment replacement methodological approach that considers uncertainty and risk on the one hand and also allows for the incorporation of real data over the assets lifetime on the other, the use of an MCS probabilistic NPV based model was found to be the optimal approach to be adopted. The result of updating the static NPV model with updated data as soon as it is obtained enables one to generate accurate probabilistic distribution functions required for the subsequent MCS analysis. By adopting this approach the study has concluded that one can obtain realistic and accurate NPV forecasts from the anticipated FCF estimates. The principal conclusion obtained from this study is that the optimal time in which to replace front line assets employed at B&E International is when the probabilistic net earnings profile, viz., NPV of the equipment is maximized.
- Full Text:
- Date Issued: 2018
- Authors: Basson, Kenneth Mervyn
- Date: 2018
- Subjects: Decision making , Industrial equipment Industrial equipment -- Maintenance and repair
- Language: English
- Type: Thesis , Doctoral , DBA
- Identifier: http://hdl.handle.net/10948/23647 , vital:30592
- Description: At present, frontline equipment employed at B&E International, and operating within the quarrying sector is typically replaced as soon as the operating expenses are deemed to be excessive. From a capital budgeting perspective, the trigger for signalling the replacement of equipment occurs when prescribed operating cost performance metrics are violated. In some instances, a further consideration for motivating the replacement of equipment is when the perception arises that the nonavailability of the equipment employed, results in financial losses being incurred by a company. It can therefore be argued that the current equipment replacement timing methodological approach adopted at B&E International is suboptimal in nature. The situation is further aggravated by the fact that in many instances, escalation of commitment manifests itself whereby unnecessary capital is repeatedly invested in order to extend the life of an asset resulting in a situation occurring whereby the required level of investment return is not achieved. In the event of these situations arising, the decision to replace an asset is prolonged as a result of the suboptimal investment decisions being made. The primary focus of this study is to provide a methodological equipment replacement framework that is based upon sound capital budgeting fundamentals. A comprehensive literature review of capital budgeting approaches that specifically focus on the optimal replacement timing of frontline quarrying equipment, did not yield any relevant studies that have been undertaken in this regard. This study did however investigate contemporary equipment replacement approaches based upon a capital budgeting paradigm and highlighted their respective limitations. Convincing evidence obtained, indicated that the most widely accepted method of identifying the optimal replacement timing of equipment occurs when the economic life of the asset is attained. This in itself would therefore infer that a cost minimisation approach is the most pervasive methodological approach adopted in order to identify the optimal replacement timing of equipment. When considering capital investment based decisions, it was found that the discounted cash flow based methodologies are the most widely used and accepted approach applied in the mining industry. Notwithstanding this, one major caveat manifests itself in that when considering the optimal replacement timing of front line equipment within the quarrying industry, the inclusion of uncertainty, flexibility and the associated financial risks was not evident. In order to model these effects, a probabilistic Net Present Value (NPV) approach was adopted and the required Discounted Cash Flow (DCF) models were constructed. Given the uncertainty of the expected cumulative R&M profiles for the asset classes constituting this study, an extensive statistical analysis was carried out in order to establish the required predictive Repair and Maintenance (R&M) models required for the DCF analysis by means of regression analysis. Further regression analyses were conducted in order to model the overall availability and utilisation metrics for the respective asset classes included in this study. The consequence of incurring downtime was investigated and the resultant DCF analysis yielded a significant impact on the Free Cash Flow (FCF) generated by the respective assets. The magnitude of the incurred consequential financial losses incurred as a result of the respective downtime was found to be significant when considering frontline equipment. In order to model the effect of, and the extent to which, the respective independent variables influence the static NPV outcome, a sensitivity analysis was performed. From this, the influence of the independent variables constituting the NPV model employed in this study, were observed. A Real Options Analysis (ROA) approach was initially employed in order to model the effects of FCF uncertainty and the results of carrying out this analysis indicated a minimal influence on the static NPV model referred to earlier. It was therefore concluded that from an equipment replacement timing perspective, the ROA approach did not provide a robust and accurate representation of the probabilistic NPV outcomes anticipated. In order to address these perceived shortcomings, an Monte Carlo Simulation (MCS) model was constructed and the requisite probability distribution functions representing the most influential independent variables determined from the sensitivity analysis were identified and subsequently analysed. The results of the MCS analysis yielded the expected NPV outcomes that were found to be far more conservative compared to the static NPV outcomes referred to previously. Furthermore, the concluding findings of this study indicate that in order to estimate the optimal time to dispose of an asset, a static NPV analysis must first be modelled and thereafter a probabilistic NPV analysis. The respective uncertainty aspects over the lifespan of the assets should be identified to be incorporated into the MCS model. This methodological approach therefore opposes the use of a strictly deterministic based approach and rather predicates the use of a probabilistic NPV based framework. This study further concluded that traditional DCF approaches fail to consider management flexibility in terms of adapting to uncertainty and to also reduce the possibility of “escalation of commitment” occurring as a result of sub-optimal equipment replacement timing decisions by management. The use and acceptance of the traditional DCF approaches are acknowledged, but in order to develop an equipment replacement methodological approach that considers uncertainty and risk on the one hand and also allows for the incorporation of real data over the assets lifetime on the other, the use of an MCS probabilistic NPV based model was found to be the optimal approach to be adopted. The result of updating the static NPV model with updated data as soon as it is obtained enables one to generate accurate probabilistic distribution functions required for the subsequent MCS analysis. By adopting this approach the study has concluded that one can obtain realistic and accurate NPV forecasts from the anticipated FCF estimates. The principal conclusion obtained from this study is that the optimal time in which to replace front line assets employed at B&E International is when the probabilistic net earnings profile, viz., NPV of the equipment is maximized.
- Full Text:
- Date Issued: 2018
The development of an optimised rotor software design tool to improve performance of small horizontal axis wind turbines
- Authors: Newey, Kerryn Brett
- Date: 2012
- Subjects: Wind turbines -- Design , Wind power , Turbines -- Design
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9620 , http://hdl.handle.net/10948/d1009431 , Wind turbines -- Design , Wind power , Turbines -- Design
- Description: Horizontal axis wind turbines are by far the most common and well understood forms of wind turbine. Typically a large amount of research and development has been invested in the technology of large scale wind turbines. Unfortunately, development of small machines (rotor diameter smaller than 10 metres) has not been as forthcoming. The advantages of small turbines are that they are accessible to the individual consumer and they are a very attractive project for the home builder. The disadvantage of small turbines is that due to the negative influence of economies of scale, they tend to be costly in relation to their power output and suffer from a long-term return on investment. Furthermore, trends in the wind industry have shown that smaller machines tend to be relatively simple devices that have been developed with very little research and development. As a result, small turbines can be inefficient, unreliable and expensive to maintain. In many cases rotor design is less than optimal, with very little blade refinement. This is especially critical for small rotors due to low Reynolds Number operation. Further exacerbating the problem is that the rotors are typically not well matched to the generator. In many cases the machines are not suited to the wind speed range in which they are designed to operate, reducing the financial viability due to poor performance. It is envisaged that by applying optimising techniques and automating some of the design complexities into a software design tool, more cost-effective and viable machines can be developed that will deliver improved performance and therefore become more financially viable.
- Full Text:
- Date Issued: 2012
- Authors: Newey, Kerryn Brett
- Date: 2012
- Subjects: Wind turbines -- Design , Wind power , Turbines -- Design
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9620 , http://hdl.handle.net/10948/d1009431 , Wind turbines -- Design , Wind power , Turbines -- Design
- Description: Horizontal axis wind turbines are by far the most common and well understood forms of wind turbine. Typically a large amount of research and development has been invested in the technology of large scale wind turbines. Unfortunately, development of small machines (rotor diameter smaller than 10 metres) has not been as forthcoming. The advantages of small turbines are that they are accessible to the individual consumer and they are a very attractive project for the home builder. The disadvantage of small turbines is that due to the negative influence of economies of scale, they tend to be costly in relation to their power output and suffer from a long-term return on investment. Furthermore, trends in the wind industry have shown that smaller machines tend to be relatively simple devices that have been developed with very little research and development. As a result, small turbines can be inefficient, unreliable and expensive to maintain. In many cases rotor design is less than optimal, with very little blade refinement. This is especially critical for small rotors due to low Reynolds Number operation. Further exacerbating the problem is that the rotors are typically not well matched to the generator. In many cases the machines are not suited to the wind speed range in which they are designed to operate, reducing the financial viability due to poor performance. It is envisaged that by applying optimising techniques and automating some of the design complexities into a software design tool, more cost-effective and viable machines can be developed that will deliver improved performance and therefore become more financially viable.
- Full Text:
- Date Issued: 2012
The development of an orodispersible sildenafil citrate tablet intended for paediatric use
- Authors: Dagnolo, Bianca
- Date: 2012
- Subjects: Drug development -- Children -- Research -- South Africa , Pulmonary hypertension -- Children -- Research , Tablets (Medicine) -- Development , Pharmaceutical chemistry -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3751 , http://hdl.handle.net/10962/d1003229 , Drug development -- Children -- Research -- South Africa , Pulmonary hypertension -- Children -- Research , Tablets (Medicine) -- Development , Pharmaceutical chemistry -- Research
- Description: Sildenafil citrate (SC) is a phosphodiesterase-5 inhibitor that is used to treat pulmonary hypertension (PH) in paediatric patients. The purpose of these studies was to develop a formulation and manufacture an orodispersible tablet (ODT) that can be easily administered to neonates and children with PH. The advantages of ODT dosage forms include ease of administration, rapid dissolution of the API, SC. Furthermore the dosage form can be taken without water which is beneficial to patients without immediate access to potable fluids. A simple, rapid, accurate, precise and selective reversed-phase HPLC method was developed and validated in accordance with International Conference on Harmonization (ICH) guidelines and was successfully used for the analysis of SC as raw material and in SC containing pharmaceutical dosage forms. Preformulation studies were performed on SC, alone and in combination with potential excipients that could be used to make tablets. Investigations into potential interactions between SC and the excipients were performed using Differential Scanning Calorimetry (DSC) and Infrared Spectroscopy (IR). DSC results revealed that SC was compatible with all potential excipients except mannitol and magnesium stearate. However these interactions were not observed with IR and therefore it was concluded that the interactions were induced by the high temperatures that DSC operates at. Particle size and shape was also established by use of Scanning Electron Microscopy (SEM) and flow properties were monitored by calculating Carr’s Index (CI) and the Hausner Ratio (HR). Direct compression was used as the method of manufacture for SC tablets as this approach is simple and the most economic production approach. The powder blends were assessed for bulk and tapped density and the CI and HR were used to determine the flowability of the blends. The quality attributes of the resultant tablets that were monitored included uniformity of weight, friability, crushing strength, tensile strength, disintegration, wetting and in vitro dispersion times. Design of Experiments is an efficient statistical approach that has become a popular tool used in the pharmaceutical industry to optimize formulation compositions, as it allows for the investigation of several input factors at the same time whilst not using the tedious and traditional “ modification of one variable at a time” approach. A Central composite experimental design was chosen as the most appropriate means to optimize the formulation as it produces more accurate results as opposed to other experimental designs approaches as input factors are investigated at five different levels. Through the use of mathematical modelling, optimum concentrations of disintegrant(s) and an appropriate blending time were established. Analysis of the data from the experimental design and mathematical modelling studies reveal that no changes in disintegrant concentration or blending time altered the disintegration time of the formulation to any significant extent. This result is most likely due to the fact that the critical disintegrant concentration has been reached and increasing the disintegrant concentration further has no effect on disintegration time. It was also established that a change in the concentration of CMS and CRP altered the wetting time of the tablet significantly. Finally it was noted that there was a linear relationship between blending time and the uniformity of content of the tablets produced in these studies. The optimized product was a white tablet with a diameter of 7.31 mm with a thickness of 2.80mm.The dosage form had no visible cracks or evidence of picking or sticking. The tablet exhibits suitable friability and tensile strength while exhibiting a disintegration time of only 8s. Therefore an orodispersible tablet containing SC intended for paediatric use has been successfully developed, manufactured and optimized through the use of preformulation studies, appropriate quality control monitoring and mathematical modelling. These formulations require further optimization in respect of addition of flavours and or additional sweetening agents.
- Full Text:
- Date Issued: 2012
- Authors: Dagnolo, Bianca
- Date: 2012
- Subjects: Drug development -- Children -- Research -- South Africa , Pulmonary hypertension -- Children -- Research , Tablets (Medicine) -- Development , Pharmaceutical chemistry -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3751 , http://hdl.handle.net/10962/d1003229 , Drug development -- Children -- Research -- South Africa , Pulmonary hypertension -- Children -- Research , Tablets (Medicine) -- Development , Pharmaceutical chemistry -- Research
- Description: Sildenafil citrate (SC) is a phosphodiesterase-5 inhibitor that is used to treat pulmonary hypertension (PH) in paediatric patients. The purpose of these studies was to develop a formulation and manufacture an orodispersible tablet (ODT) that can be easily administered to neonates and children with PH. The advantages of ODT dosage forms include ease of administration, rapid dissolution of the API, SC. Furthermore the dosage form can be taken without water which is beneficial to patients without immediate access to potable fluids. A simple, rapid, accurate, precise and selective reversed-phase HPLC method was developed and validated in accordance with International Conference on Harmonization (ICH) guidelines and was successfully used for the analysis of SC as raw material and in SC containing pharmaceutical dosage forms. Preformulation studies were performed on SC, alone and in combination with potential excipients that could be used to make tablets. Investigations into potential interactions between SC and the excipients were performed using Differential Scanning Calorimetry (DSC) and Infrared Spectroscopy (IR). DSC results revealed that SC was compatible with all potential excipients except mannitol and magnesium stearate. However these interactions were not observed with IR and therefore it was concluded that the interactions were induced by the high temperatures that DSC operates at. Particle size and shape was also established by use of Scanning Electron Microscopy (SEM) and flow properties were monitored by calculating Carr’s Index (CI) and the Hausner Ratio (HR). Direct compression was used as the method of manufacture for SC tablets as this approach is simple and the most economic production approach. The powder blends were assessed for bulk and tapped density and the CI and HR were used to determine the flowability of the blends. The quality attributes of the resultant tablets that were monitored included uniformity of weight, friability, crushing strength, tensile strength, disintegration, wetting and in vitro dispersion times. Design of Experiments is an efficient statistical approach that has become a popular tool used in the pharmaceutical industry to optimize formulation compositions, as it allows for the investigation of several input factors at the same time whilst not using the tedious and traditional “ modification of one variable at a time” approach. A Central composite experimental design was chosen as the most appropriate means to optimize the formulation as it produces more accurate results as opposed to other experimental designs approaches as input factors are investigated at five different levels. Through the use of mathematical modelling, optimum concentrations of disintegrant(s) and an appropriate blending time were established. Analysis of the data from the experimental design and mathematical modelling studies reveal that no changes in disintegrant concentration or blending time altered the disintegration time of the formulation to any significant extent. This result is most likely due to the fact that the critical disintegrant concentration has been reached and increasing the disintegrant concentration further has no effect on disintegration time. It was also established that a change in the concentration of CMS and CRP altered the wetting time of the tablet significantly. Finally it was noted that there was a linear relationship between blending time and the uniformity of content of the tablets produced in these studies. The optimized product was a white tablet with a diameter of 7.31 mm with a thickness of 2.80mm.The dosage form had no visible cracks or evidence of picking or sticking. The tablet exhibits suitable friability and tensile strength while exhibiting a disintegration time of only 8s. Therefore an orodispersible tablet containing SC intended for paediatric use has been successfully developed, manufactured and optimized through the use of preformulation studies, appropriate quality control monitoring and mathematical modelling. These formulations require further optimization in respect of addition of flavours and or additional sweetening agents.
- Full Text:
- Date Issued: 2012
The development of armature based ceramics using South African raw materials
- Authors: Luyt, Michelle
- Date: 2018
- Subjects: Pottery -- Research -- South Africa , Pottery craft -- South Africa -- Technique Ceramics in interior decoration -- South Africa
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: http://hdl.handle.net/10948/22618 , vital:30028
- Description: The purpose of the research was to develop a procedure by which South African ceramicists can use locally sourced ceramic materials to create armature based art forms, without having to rely on the importation of raw materials. The study also investigated the suitability of wire armatures as well as variable temperature ranges applicable to this investigation. It was found that commercial clay slip bodies purchased from South African suppliers tended to crack when coated over wire armatures during the firing process. It was shown that by substituting South African ceramic raw materials in the John W. Conrad’s C25 casting slip and Jeremy Dubber’s Ascent casting slip formulae with the addition of paper pulp and potassium feldspar, reduced the problem of the clay cracking when applied to wire armatures. The addition of paper fibres gave the clay bodies strong adhesive qualities which allowed the clay them to adhere onto the wire armatures which prevented the dry clay coatings from chipping off prior to and after firing. The addition of potassium feldspar helped with the maturing point of both the clay bodies and helped fuse the clay particles together which strengthened the clay coatings after being fired to their respective maturing temperatures. A further application of hydrochloric acid 30% or Pro Grip Key Coat ® to the three wire armature types, being galvanized binding wire, galvanized diamond mesh and Kanthal wire prior to coating with the above two formulae improved the adhesion of the clay slips to the armatures. This prevented them from the tendency to slide off the wire during the dipping and pouring process and helped eliminate any cracks that formed during the firing process. However, the glazing of the clay slips above proved to be problematic where it was sought as a further enhancement of the clay coated wire armatures. A general-purpose earthenware glaze caused the fired clay coating to crack probably due to the increased tension between the wire, clay body and the glaze. This problem was solved by developing a low firing transparent glaze. Other decorative effects were achieved by the inclusion of 0.5% cobalt oxide into the low firing transparent glaze which produced a blemish free deep blue colour. A further effect was achieved using binding copper wire over the bisque ware and then glazing with the low firing transparent glaze. A smoke firing technique as well an application of a copper oxide wash to the bisque fired ware and then re-firing to the required maturing temperature produced pleasing results.
- Full Text:
- Date Issued: 2018
- Authors: Luyt, Michelle
- Date: 2018
- Subjects: Pottery -- Research -- South Africa , Pottery craft -- South Africa -- Technique Ceramics in interior decoration -- South Africa
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: http://hdl.handle.net/10948/22618 , vital:30028
- Description: The purpose of the research was to develop a procedure by which South African ceramicists can use locally sourced ceramic materials to create armature based art forms, without having to rely on the importation of raw materials. The study also investigated the suitability of wire armatures as well as variable temperature ranges applicable to this investigation. It was found that commercial clay slip bodies purchased from South African suppliers tended to crack when coated over wire armatures during the firing process. It was shown that by substituting South African ceramic raw materials in the John W. Conrad’s C25 casting slip and Jeremy Dubber’s Ascent casting slip formulae with the addition of paper pulp and potassium feldspar, reduced the problem of the clay cracking when applied to wire armatures. The addition of paper fibres gave the clay bodies strong adhesive qualities which allowed the clay them to adhere onto the wire armatures which prevented the dry clay coatings from chipping off prior to and after firing. The addition of potassium feldspar helped with the maturing point of both the clay bodies and helped fuse the clay particles together which strengthened the clay coatings after being fired to their respective maturing temperatures. A further application of hydrochloric acid 30% or Pro Grip Key Coat ® to the three wire armature types, being galvanized binding wire, galvanized diamond mesh and Kanthal wire prior to coating with the above two formulae improved the adhesion of the clay slips to the armatures. This prevented them from the tendency to slide off the wire during the dipping and pouring process and helped eliminate any cracks that formed during the firing process. However, the glazing of the clay slips above proved to be problematic where it was sought as a further enhancement of the clay coated wire armatures. A general-purpose earthenware glaze caused the fired clay coating to crack probably due to the increased tension between the wire, clay body and the glaze. This problem was solved by developing a low firing transparent glaze. Other decorative effects were achieved by the inclusion of 0.5% cobalt oxide into the low firing transparent glaze which produced a blemish free deep blue colour. A further effect was achieved using binding copper wire over the bisque ware and then glazing with the low firing transparent glaze. A smoke firing technique as well an application of a copper oxide wash to the bisque fired ware and then re-firing to the required maturing temperature produced pleasing results.
- Full Text:
- Date Issued: 2018
The development of athletics in South Africa: 1814 to 1914
- Authors: Coghlan, Douglas Victor
- Date: 1987
- Subjects: Athletics -- South Africa -- History
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/60785 , vital:27830
- Description: The purpose of this study was to record the development of athletics in South Africa from 1814 to 1914. This period was chosen because sport and athletics originated and developed a social institution during that time and the First World brought progress to a temporary halt, after which there were many new developments. The Cape Colony became British in 1814, and it was British influence that played such a dominant role in the social history of the period.
- Full Text:
- Date Issued: 1987
- Authors: Coghlan, Douglas Victor
- Date: 1987
- Subjects: Athletics -- South Africa -- History
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/60785 , vital:27830
- Description: The purpose of this study was to record the development of athletics in South Africa from 1814 to 1914. This period was chosen because sport and athletics originated and developed a social institution during that time and the First World brought progress to a temporary halt, after which there were many new developments. The Cape Colony became British in 1814, and it was British influence that played such a dominant role in the social history of the period.
- Full Text:
- Date Issued: 1987