The development of a commercial production process for p-menthane-3,8-diol
- Authors: Rust, Nico
- Date: 2009
- Subjects: Insect pests -- Control , Repellents
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:10427 , http://hdl.handle.net/10948/d1018273
- Description: The synthesis of p-menthane-3,8-diol via the acid-catalyzed cyclization of citronellal in a dilute aqueous sulphuric acid medium was investigated using conventional batch and continuous systems in order to develop a commercial production process for said p-menthane-3,8-diol (PMD). The batch studies conducted during the first part of this study showed that the formation of PMD from citronellal occurs via an intra-molecular Prins reaction that results in the formation of both the desired PMD product, as well as the partially hydrated isopulegol. It was shown that the formationof the by- product, PMD-acetal, results from the reaction between an intermediate, 5-methyl-2- isopropylcyclohexanol, and the citronellal starting material, and not from the reaction between PMD and citronellal as previously reported. Kinetic studies confirmed the existence of a complicated kinetic model. The formation of PMD from citronellal displayed typical pseudo first order kinetics up to conversions of 70 after which the kinetic model becomes complicated as the result of the establishment of quasi equilibrium reactions between PMD and isopulegol (dehydration of PMD and hydration of isopulegol) and between PMD the PMD-acetal, both systems being acid catalysed. The PMD-acetal formation reaction appears to be second order with respect to PMD. Scale-up studies of the batch process to 30L and 50L scales showed that it would be extremely difficult to limit the level of PMD-acetal formation below the desired level of 1 percent, even if citronellal conversions are restricted to about 50 percent. During studies conducted on a commercially availablemicro-structured organic synthesis plant (OSP) it was shown that it is possible to perform the PMD reaction as a continuous process. The results obtained showed that the use of a micro-mixer such as the caterpillar micro-mixer did not provide enough residence time in order for desirable conversions (- 40 percent) to be obtained. By combining themicro-mixer with delay-loops of different thicknesses and lengths, and using increasing reaction temperatures, it was shown that the conversion of citronellal could be improved to some extent, but compared poorly to the expected conversions for a well-stirred batch reactor. By packing selected delay loops with inert SiC particles, improved mass transfer was observed between the organic and aqueous phases as reflected in the increased conversion of citronellal. Using the observations that were made during the use of the OSP, a continuous-flow, tubular reactor system was designed and constructed. Advanced statistical techniques were used to investigate the effect of variables such as temperature, acid concentration, reactor length, flow rate and the organic to aqueous ratio on the rate and selectivity of the reaction. Mathematical models were derived for citronellal conversion, yield of PMD and yield of PMD- acetals, and used to predict the concentrations of citronellal, PMD and PMD-acetals at set experimental conditions. The results obtained showed that it was possible to obtain a product which approached desired specifications.Downstream processing of the PMD reaction mixture as it exits the reactor requires phase separation and neutralization of the acid catalyst solution, followed by further work-up to recover unreacted starting material and intermediates for recycle back to the synthesis reactor, followed by purification of crude PMD to the desired specification. The study showed that neutralization, prior or after phase separation, does not affect the selectivity of the PMD to such a great extent, but does influence the relative conversion due to extended contact of the catalyst with the organic phase after the reaction is terminated. Recovery of unreacted citronellal and isopulegol could be achieved by a simple vacuum evaporation step, which may either be carried out in a batch manner using traditional distillation equipment, or in a continuous process using wiped-film (short path) techniques. It was also shown that selective crystallization of PMD from the crude product mixture by addition of a solvent, such as heptanes or hexane proved to be the best way of achieving the desired product specification.
- Full Text:
- Date Issued: 2009
- Authors: Rust, Nico
- Date: 2009
- Subjects: Insect pests -- Control , Repellents
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:10427 , http://hdl.handle.net/10948/d1018273
- Description: The synthesis of p-menthane-3,8-diol via the acid-catalyzed cyclization of citronellal in a dilute aqueous sulphuric acid medium was investigated using conventional batch and continuous systems in order to develop a commercial production process for said p-menthane-3,8-diol (PMD). The batch studies conducted during the first part of this study showed that the formation of PMD from citronellal occurs via an intra-molecular Prins reaction that results in the formation of both the desired PMD product, as well as the partially hydrated isopulegol. It was shown that the formationof the by- product, PMD-acetal, results from the reaction between an intermediate, 5-methyl-2- isopropylcyclohexanol, and the citronellal starting material, and not from the reaction between PMD and citronellal as previously reported. Kinetic studies confirmed the existence of a complicated kinetic model. The formation of PMD from citronellal displayed typical pseudo first order kinetics up to conversions of 70 after which the kinetic model becomes complicated as the result of the establishment of quasi equilibrium reactions between PMD and isopulegol (dehydration of PMD and hydration of isopulegol) and between PMD the PMD-acetal, both systems being acid catalysed. The PMD-acetal formation reaction appears to be second order with respect to PMD. Scale-up studies of the batch process to 30L and 50L scales showed that it would be extremely difficult to limit the level of PMD-acetal formation below the desired level of 1 percent, even if citronellal conversions are restricted to about 50 percent. During studies conducted on a commercially availablemicro-structured organic synthesis plant (OSP) it was shown that it is possible to perform the PMD reaction as a continuous process. The results obtained showed that the use of a micro-mixer such as the caterpillar micro-mixer did not provide enough residence time in order for desirable conversions (- 40 percent) to be obtained. By combining themicro-mixer with delay-loops of different thicknesses and lengths, and using increasing reaction temperatures, it was shown that the conversion of citronellal could be improved to some extent, but compared poorly to the expected conversions for a well-stirred batch reactor. By packing selected delay loops with inert SiC particles, improved mass transfer was observed between the organic and aqueous phases as reflected in the increased conversion of citronellal. Using the observations that were made during the use of the OSP, a continuous-flow, tubular reactor system was designed and constructed. Advanced statistical techniques were used to investigate the effect of variables such as temperature, acid concentration, reactor length, flow rate and the organic to aqueous ratio on the rate and selectivity of the reaction. Mathematical models were derived for citronellal conversion, yield of PMD and yield of PMD- acetals, and used to predict the concentrations of citronellal, PMD and PMD-acetals at set experimental conditions. The results obtained showed that it was possible to obtain a product which approached desired specifications.Downstream processing of the PMD reaction mixture as it exits the reactor requires phase separation and neutralization of the acid catalyst solution, followed by further work-up to recover unreacted starting material and intermediates for recycle back to the synthesis reactor, followed by purification of crude PMD to the desired specification. The study showed that neutralization, prior or after phase separation, does not affect the selectivity of the PMD to such a great extent, but does influence the relative conversion due to extended contact of the catalyst with the organic phase after the reaction is terminated. Recovery of unreacted citronellal and isopulegol could be achieved by a simple vacuum evaporation step, which may either be carried out in a batch manner using traditional distillation equipment, or in a continuous process using wiped-film (short path) techniques. It was also shown that selective crystallization of PMD from the crude product mixture by addition of a solvent, such as heptanes or hexane proved to be the best way of achieving the desired product specification.
- Full Text:
- Date Issued: 2009
Customer satisfaction with the guesthouse experience in Ghana
- Authors: Amoah, Felix
- Date: 2016
- Subjects: Consumer satisfaction -- Ghana , Hospitality industry -- Ghana -- Management , Tourism -- Ghana -- Marketing
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: http://hdl.handle.net/10948/6073 , vital:21036
- Description: Guesthouse accommodation plays an important role in Ghana’s hospitality industry and was therefore the focus of this study as little research dealing with guesthouses in Ghana could be found. The number of guesthouses in Ghana continues to grow and they thus represent an important alternative to hotels. However, these establishments seem to perform poorly and face several challenges such as lack of managerial knowledge, insufficiently skilled employees, poor interaction with customers, and criticisms of the provision of low quality service. The main reason for undertaking this research was to provide guesthouse managers in Ghana with information that might assist them in making decisions about the experience they offer. Such knowledge could make this type of accommodation more competitive and eventually help the hospitality sector in Ghana attract tourists and grow. It is imperative that guesthouses focus on the experience they offer, because contemporary tourism and hospitality literature suggest that successful businesses require a shift from functional and financial interests to a more profound focus on total experiences which embody emotional aspects. It is thus argued that, if guesthouse managers in Ghana do not know how their guests perceive their guesthouse experience, they might make costly mistakes and allocate resources to aspects that already provide quality and value in a functional sense, instead of those elements perceived as providing quality and value in the total experience. Two dominating concepts, namely experience quality and experience value, formed the basis of the examination of guests’ experience with the guesthouses in Ghana. In addition, the relationships between the experience and satisfaction were also investigated. Four experience quality dimensions, namely hedonics, peace of mind, involvement, and recognition, and seven value dimensions were examined. The experience value dimensions included atmospherics, enjoyment, entertainment, efficiency, excellence, escape, and economic value. A proportional stratified random sampling procedure was followed to select the guesthouses for the study. Thereafter, a structured questionnaire was distributed to the guesthouse guests selected by means of convenience sampling. Five hundred and forty one useable questionnaires were received. The guesthouse guests formed the primary sampling unit for this study. The results of the empirical study showed a strong positive correlation between all the dimensions of experience quality and experience value, while the factor analysis confirmed that all these dimensions loaded on a single factor. Therefore, experience quality and experience value cannot be separated, and the resulting single multi-dimensional factor was subsequently renamed, overall experience. The results also indicated a positive relationship between hedonics, peace of mind, involvement, recognition, atmospherics, enjoyment, entertainment, efficiency, excellence, escape, economic value, and overall satisfaction. The inferentially established rank-order of the dimensions contributing to satisfaction can guide managers when allocating resources. Overall, atmospherics was ranked first, followed by economic value. Escape was the lowest ranked dimension. In addition, it was found that, except for escape, all the experience dimensions were perceived as basic satisfiers. This implies that guests will be dissatisfied when provision of these dimensions is inadequate. With regard to escape, listed as a performance factor, guests will be satisfied when performance is improved and dissatisfied when performance is low. A positive relationship was also found between overall experience and overall satisfaction. The latter include the likelihood of return and recommending the guesthouse to others. Finally, structural equation modelling confirmed a model representing the 11 experience dimensions (hedonics, peace of mind, involvement, recognition, atmospherics, enjoyment, entertainment, escape, efficiency, excellence, and economic value) and the relationships between overall experience and overall satisfaction pertaining to guesthouses in Ghana.
- Full Text:
- Date Issued: 2016
- Authors: Amoah, Felix
- Date: 2016
- Subjects: Consumer satisfaction -- Ghana , Hospitality industry -- Ghana -- Management , Tourism -- Ghana -- Marketing
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: http://hdl.handle.net/10948/6073 , vital:21036
- Description: Guesthouse accommodation plays an important role in Ghana’s hospitality industry and was therefore the focus of this study as little research dealing with guesthouses in Ghana could be found. The number of guesthouses in Ghana continues to grow and they thus represent an important alternative to hotels. However, these establishments seem to perform poorly and face several challenges such as lack of managerial knowledge, insufficiently skilled employees, poor interaction with customers, and criticisms of the provision of low quality service. The main reason for undertaking this research was to provide guesthouse managers in Ghana with information that might assist them in making decisions about the experience they offer. Such knowledge could make this type of accommodation more competitive and eventually help the hospitality sector in Ghana attract tourists and grow. It is imperative that guesthouses focus on the experience they offer, because contemporary tourism and hospitality literature suggest that successful businesses require a shift from functional and financial interests to a more profound focus on total experiences which embody emotional aspects. It is thus argued that, if guesthouse managers in Ghana do not know how their guests perceive their guesthouse experience, they might make costly mistakes and allocate resources to aspects that already provide quality and value in a functional sense, instead of those elements perceived as providing quality and value in the total experience. Two dominating concepts, namely experience quality and experience value, formed the basis of the examination of guests’ experience with the guesthouses in Ghana. In addition, the relationships between the experience and satisfaction were also investigated. Four experience quality dimensions, namely hedonics, peace of mind, involvement, and recognition, and seven value dimensions were examined. The experience value dimensions included atmospherics, enjoyment, entertainment, efficiency, excellence, escape, and economic value. A proportional stratified random sampling procedure was followed to select the guesthouses for the study. Thereafter, a structured questionnaire was distributed to the guesthouse guests selected by means of convenience sampling. Five hundred and forty one useable questionnaires were received. The guesthouse guests formed the primary sampling unit for this study. The results of the empirical study showed a strong positive correlation between all the dimensions of experience quality and experience value, while the factor analysis confirmed that all these dimensions loaded on a single factor. Therefore, experience quality and experience value cannot be separated, and the resulting single multi-dimensional factor was subsequently renamed, overall experience. The results also indicated a positive relationship between hedonics, peace of mind, involvement, recognition, atmospherics, enjoyment, entertainment, efficiency, excellence, escape, economic value, and overall satisfaction. The inferentially established rank-order of the dimensions contributing to satisfaction can guide managers when allocating resources. Overall, atmospherics was ranked first, followed by economic value. Escape was the lowest ranked dimension. In addition, it was found that, except for escape, all the experience dimensions were perceived as basic satisfiers. This implies that guests will be dissatisfied when provision of these dimensions is inadequate. With regard to escape, listed as a performance factor, guests will be satisfied when performance is improved and dissatisfied when performance is low. A positive relationship was also found between overall experience and overall satisfaction. The latter include the likelihood of return and recommending the guesthouse to others. Finally, structural equation modelling confirmed a model representing the 11 experience dimensions (hedonics, peace of mind, involvement, recognition, atmospherics, enjoyment, entertainment, escape, efficiency, excellence, and economic value) and the relationships between overall experience and overall satisfaction pertaining to guesthouses in Ghana.
- Full Text:
- Date Issued: 2016
The development of motivational strategies for public sector workers in Kenya
- Authors: Chepkilot, Ronald Kiprop
- Date: 2005
- Subjects: Public administration -- Kenya , Employee motivation , Civil service -- Kenya -- Personnel management
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:9380 , http://hdl.handle.net/10948/161 , Public administration -- Kenya , Employee motivation , Civil service -- Kenya -- Personnel management
- Description: The purpose of this study was to develop motivational strategies for motivating public sector workers in Kenya. To achieve this objective the following procedure was followed: • An examination of the public service was undertaken and the following factors were considered: The history of the public service; Past government reform programmes; The problem of corruption; Future government reform programmes; and The motivational climate in the service. iv • A literature survey was conducted on the approaches used by organisations in motivating employees. The findings were used to develop a motivational strategy model. On the basis of the strategies in the model, a questionnaire was developed for the empirical research study. • The empirical study was undertaken to examine the level of motivation in the public service and to identify the motivational strategies currently used in the public service in Kenya. The study also sought to determine the extent to which public sector managers agreed or disagreed that the motivational strategies developed by the study would be effective in motivating employees in their organisations. The results of the empirical study were incorporated into the integrated motivational strategy model presented in chapter six. The study established that the level of motivation among the public sector workers was extremely low. According to the research findings, 87 per cent of the respondents indicated that the level of motivation of employees in their organisation was low while 13 per cent indicated that it was high. It was also established that the climate in the public service was not conducive for motivating employees: the indicators were lack of job security; very low salaries; limited training and development opportunities; lack of career development programmes and lack of adequate working tools and equipment. It was further established that the government could no longer afford to make any substantial increases in salaries to the workers because the wage bill was extremely high at the level of 9.6 per cent of the GDP. It was observed that any further increases in salaries would v have a negative impact on the economy of the country. In view of the above, this study becomes extremely relevant as it suggests ways of enhancing the levels of motivation in the public service to improve service delivery in the public sector without allocation of vast financial resources. The study strongly recommends the application of the integrated motivational strategy model in its entirety; to enhance the level of employee’s motivation and work performance and achieve efficiency and effectiveness in service delivery. The study also recommends that further research be carried out to determine the effects of corruption on employee motivation and ways of eliminating the vice in the public service.
- Full Text:
- Date Issued: 2005
- Authors: Chepkilot, Ronald Kiprop
- Date: 2005
- Subjects: Public administration -- Kenya , Employee motivation , Civil service -- Kenya -- Personnel management
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:9380 , http://hdl.handle.net/10948/161 , Public administration -- Kenya , Employee motivation , Civil service -- Kenya -- Personnel management
- Description: The purpose of this study was to develop motivational strategies for motivating public sector workers in Kenya. To achieve this objective the following procedure was followed: • An examination of the public service was undertaken and the following factors were considered: The history of the public service; Past government reform programmes; The problem of corruption; Future government reform programmes; and The motivational climate in the service. iv • A literature survey was conducted on the approaches used by organisations in motivating employees. The findings were used to develop a motivational strategy model. On the basis of the strategies in the model, a questionnaire was developed for the empirical research study. • The empirical study was undertaken to examine the level of motivation in the public service and to identify the motivational strategies currently used in the public service in Kenya. The study also sought to determine the extent to which public sector managers agreed or disagreed that the motivational strategies developed by the study would be effective in motivating employees in their organisations. The results of the empirical study were incorporated into the integrated motivational strategy model presented in chapter six. The study established that the level of motivation among the public sector workers was extremely low. According to the research findings, 87 per cent of the respondents indicated that the level of motivation of employees in their organisation was low while 13 per cent indicated that it was high. It was also established that the climate in the public service was not conducive for motivating employees: the indicators were lack of job security; very low salaries; limited training and development opportunities; lack of career development programmes and lack of adequate working tools and equipment. It was further established that the government could no longer afford to make any substantial increases in salaries to the workers because the wage bill was extremely high at the level of 9.6 per cent of the GDP. It was observed that any further increases in salaries would v have a negative impact on the economy of the country. In view of the above, this study becomes extremely relevant as it suggests ways of enhancing the levels of motivation in the public service to improve service delivery in the public sector without allocation of vast financial resources. The study strongly recommends the application of the integrated motivational strategy model in its entirety; to enhance the level of employee’s motivation and work performance and achieve efficiency and effectiveness in service delivery. The study also recommends that further research be carried out to determine the effects of corruption on employee motivation and ways of eliminating the vice in the public service.
- Full Text:
- Date Issued: 2005
Trust building strategies to enhance collective bargaining processes in organisations
- Authors: Ngalo, Osmond Tolo
- Date: 2011
- Subjects: Trust , Collective bargaining
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:9398 , http://hdl.handle.net/10948/1312 , Trust , Collective bargaining
- Description: The main research problem in this study was to identify what trust-building strategies can be utilised by organisations to enhance collective bargaining processes. To achieve this objective a theoretical Institutional Arrangements-Based Model of trust-building was conceptualised, developed and presented in Chapter 5. The presentation of this model was the culmination of the research design phases outlined below: -The first phase consisted of a literature survey undertaken to discover the nature and dynamics of the concept "trust". -The second phase consisted of surveying the literature attempting to understand the nature of the collective bargaining process, its elements and types and the environmental factors that tend to impinge on it. -The final phase of the literature survey focused on various trust-building strategies, theories and models that can be utilised by organisations to ii enhance collective bargaining processes. Trust is generally acknowledged as a necessary requirement for effective and successful workplace relationships. Because of this factor it is crucial that South African employer-employee relationships are improved in a conscious and sustainable way in order for our businesses to remain competitive in the face of global competition. With this reality in mind there is still much in the South African labour relations environment that fosters conflict. One of the primary factors that impinge on trust in employer-employee relations in South Africa is the previous government‘s divisive and racist apartheid policies. These policies have resulted in serious structural imbalances in the economy, the skewed distribution of wealth and the general scarcity of resources to address these attendant challenges. Finnemore and van Rensburg (2002, p. 36) surveys the current labour relations scenario and comments about the extent to which it has been severely affected by apartheid. Some of its appalling outcomes are: racial divisions between skilled and unskilled workers, apartheid wage gaps, poorly educated workers, dictatorial management styles and a lack of protection for the most vulnerable workers. As revealed in this research study there are still widely divergent views at the workplace regarding the nature and levels of trust that are prevalent. The overwhelming view, however, is that there is, generally, a lack of trust between managerial and employee collective bargaining teams. This lack of trust which is evident between employer and employee parties will tend to result in collective bargaining processes being embarked upon in a climate imbued with the negative spirit of distrust. The recommended Institutional Arrangements-Based Model of trust-building advocates for a process of trust-building prior to any collective bargaining initiatives. This process, as depicted in the elements of the recommended model, needs to begin with phases which will focus on frame-alignment and the identification of all sources of distrust between the parties. These prescribed sessions seek to culminate in a common understanding, between the contesting parties, of their real divergent issues and concerns as well as their existing commonalities. The next phases of the recommended model entail the parties, jointly, developing proposals and policies that in the short and long term will aim at the resolution of the identified sources of distrust and thereby reduce the psychological distance between them. The final phase of the model entails the implementation of joint problem–solving resolutions and the development of appropriate policies i.e. institutional arrangements, to deal with all conflict-prone areas of the business operations. Simultaneously, there needs to be continuous evaluation and monitoring of organisational trust and the "agreed to" trust-building strategies to ensure that distrust is reduced or eliminated in the long term, allowing the organisation and the individual employees to perform at their optimum in order to achieve their common goals.
- Full Text:
- Date Issued: 2011
- Authors: Ngalo, Osmond Tolo
- Date: 2011
- Subjects: Trust , Collective bargaining
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:9398 , http://hdl.handle.net/10948/1312 , Trust , Collective bargaining
- Description: The main research problem in this study was to identify what trust-building strategies can be utilised by organisations to enhance collective bargaining processes. To achieve this objective a theoretical Institutional Arrangements-Based Model of trust-building was conceptualised, developed and presented in Chapter 5. The presentation of this model was the culmination of the research design phases outlined below: -The first phase consisted of a literature survey undertaken to discover the nature and dynamics of the concept "trust". -The second phase consisted of surveying the literature attempting to understand the nature of the collective bargaining process, its elements and types and the environmental factors that tend to impinge on it. -The final phase of the literature survey focused on various trust-building strategies, theories and models that can be utilised by organisations to ii enhance collective bargaining processes. Trust is generally acknowledged as a necessary requirement for effective and successful workplace relationships. Because of this factor it is crucial that South African employer-employee relationships are improved in a conscious and sustainable way in order for our businesses to remain competitive in the face of global competition. With this reality in mind there is still much in the South African labour relations environment that fosters conflict. One of the primary factors that impinge on trust in employer-employee relations in South Africa is the previous government‘s divisive and racist apartheid policies. These policies have resulted in serious structural imbalances in the economy, the skewed distribution of wealth and the general scarcity of resources to address these attendant challenges. Finnemore and van Rensburg (2002, p. 36) surveys the current labour relations scenario and comments about the extent to which it has been severely affected by apartheid. Some of its appalling outcomes are: racial divisions between skilled and unskilled workers, apartheid wage gaps, poorly educated workers, dictatorial management styles and a lack of protection for the most vulnerable workers. As revealed in this research study there are still widely divergent views at the workplace regarding the nature and levels of trust that are prevalent. The overwhelming view, however, is that there is, generally, a lack of trust between managerial and employee collective bargaining teams. This lack of trust which is evident between employer and employee parties will tend to result in collective bargaining processes being embarked upon in a climate imbued with the negative spirit of distrust. The recommended Institutional Arrangements-Based Model of trust-building advocates for a process of trust-building prior to any collective bargaining initiatives. This process, as depicted in the elements of the recommended model, needs to begin with phases which will focus on frame-alignment and the identification of all sources of distrust between the parties. These prescribed sessions seek to culminate in a common understanding, between the contesting parties, of their real divergent issues and concerns as well as their existing commonalities. The next phases of the recommended model entail the parties, jointly, developing proposals and policies that in the short and long term will aim at the resolution of the identified sources of distrust and thereby reduce the psychological distance between them. The final phase of the model entails the implementation of joint problem–solving resolutions and the development of appropriate policies i.e. institutional arrangements, to deal with all conflict-prone areas of the business operations. Simultaneously, there needs to be continuous evaluation and monitoring of organisational trust and the "agreed to" trust-building strategies to ensure that distrust is reduced or eliminated in the long term, allowing the organisation and the individual employees to perform at their optimum in order to achieve their common goals.
- Full Text:
- Date Issued: 2011
The development and evaluation of a new manufacturing process for β-sitosterol-D glucoside
- Mtyopo, Mthetheleli Bethwell
- Authors: Mtyopo, Mthetheleli Bethwell
- Date: 2016
- Subjects: Pharmaceutical chemistry Chemistry, Organic
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: http://hdl.handle.net/10948/45920 , vital:39320
- Description: The existing production sequence of β-sitosterol-D-glucoside, a glucoside used in an “over-the-counter” (OTC) preparation under the brand name of Moducare® comprises of three process steps with an overall yield of less than 20%. The low yield is partly due to the instability of intermediates at reaction temperatures > 0oC, and partly due to the thermodynamic equilibrium between two stereoisomers. An economically alternative process was developed, evaluated and scaled-up in a 2l reactor. The project was initiated with a specific limitation in terms of the starting material that comprised a mixture of plant sterols, which necessitated a study of the isolation and purification of the desired product from a rather complex reaction mixture. The use of silver as halide acceptor for the Koenigs-Knorr synthesis did not give statistically significant different results from the same approach but using cadmium as halide acceptor instead. However, using the direct O-glucosylation approach not only gave statistically significant higher results, but also resulted in a much more convenient procedure. Under optimum conditions, a yield of approximately 83% (isolated) of 2,3,4,6- tetra-О-acetyl-β-sitosterol-D-glucoside could be achieved, which was substantially higher than that achieved with the traditional Koenigs-Knorr methodology and above reported yields in the literature (60-80%) for direct glycosylation. Separation of 2,3,4,6-tetra-О-acetyl-β-sitosterol-D-glucoside (BSSGT) from a reaction mixture that contains 2,3,4,6-tetra-О-acetyl-campesterol-D-glucoside (CSGT), 2,3,4,6-tetra-О-acetyl campestanol-glucoside (CSSGT), and 2,3,4,6-tetra-О-acetyl-sitostanol-Dglucoside (SSGT) was investigated using column chromatography. When using silica gel particles, very good separation efficiency and product recovery could be achieved using hexane/ethyl hexane as eluent. The isolated 2,3,4,6-tetra-О-acetyl-β-sitosterol-Dglucoside was easily hydrolysed to β-sitosterol-D-glucoside in high yields (79%) using methanolic KOH. The process for the production of β-sitosterol-D-glucoside was scaled-up from the laboratory bench scale (250 cm3) to a laboratory scale of 2 l using the direct Oglycosylation method. The overall yields of the scaled reaction for β-sitosterol-D-glucoside was slightly above the literature reported values (59%, 8/92) for the KnoenigsKnorr synthesis and compares well above (62%, 0/100) the current production process (less than 20% yields). When using catalogue prices, the material costs (without recycling) for the direct Oglucosylation route is approximately 57% less for the synthesis of 1kg of β-sitosterol-Dglucoside compared to the Koenigs-Knorr route. Given further savings for recycling, the direct O-glucosylation route provides an attractive alternative route for the synthesis ofthe target compound.
- Full Text:
- Date Issued: 2016
- Authors: Mtyopo, Mthetheleli Bethwell
- Date: 2016
- Subjects: Pharmaceutical chemistry Chemistry, Organic
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: http://hdl.handle.net/10948/45920 , vital:39320
- Description: The existing production sequence of β-sitosterol-D-glucoside, a glucoside used in an “over-the-counter” (OTC) preparation under the brand name of Moducare® comprises of three process steps with an overall yield of less than 20%. The low yield is partly due to the instability of intermediates at reaction temperatures > 0oC, and partly due to the thermodynamic equilibrium between two stereoisomers. An economically alternative process was developed, evaluated and scaled-up in a 2l reactor. The project was initiated with a specific limitation in terms of the starting material that comprised a mixture of plant sterols, which necessitated a study of the isolation and purification of the desired product from a rather complex reaction mixture. The use of silver as halide acceptor for the Koenigs-Knorr synthesis did not give statistically significant different results from the same approach but using cadmium as halide acceptor instead. However, using the direct O-glucosylation approach not only gave statistically significant higher results, but also resulted in a much more convenient procedure. Under optimum conditions, a yield of approximately 83% (isolated) of 2,3,4,6- tetra-О-acetyl-β-sitosterol-D-glucoside could be achieved, which was substantially higher than that achieved with the traditional Koenigs-Knorr methodology and above reported yields in the literature (60-80%) for direct glycosylation. Separation of 2,3,4,6-tetra-О-acetyl-β-sitosterol-D-glucoside (BSSGT) from a reaction mixture that contains 2,3,4,6-tetra-О-acetyl-campesterol-D-glucoside (CSGT), 2,3,4,6-tetra-О-acetyl campestanol-glucoside (CSSGT), and 2,3,4,6-tetra-О-acetyl-sitostanol-Dglucoside (SSGT) was investigated using column chromatography. When using silica gel particles, very good separation efficiency and product recovery could be achieved using hexane/ethyl hexane as eluent. The isolated 2,3,4,6-tetra-О-acetyl-β-sitosterol-Dglucoside was easily hydrolysed to β-sitosterol-D-glucoside in high yields (79%) using methanolic KOH. The process for the production of β-sitosterol-D-glucoside was scaled-up from the laboratory bench scale (250 cm3) to a laboratory scale of 2 l using the direct Oglycosylation method. The overall yields of the scaled reaction for β-sitosterol-D-glucoside was slightly above the literature reported values (59%, 8/92) for the KnoenigsKnorr synthesis and compares well above (62%, 0/100) the current production process (less than 20% yields). When using catalogue prices, the material costs (without recycling) for the direct Oglucosylation route is approximately 57% less for the synthesis of 1kg of β-sitosterol-Dglucoside compared to the Koenigs-Knorr route. Given further savings for recycling, the direct O-glucosylation route provides an attractive alternative route for the synthesis ofthe target compound.
- Full Text:
- Date Issued: 2016
A chemo-enzymatic process for the production of beta-thymidine, a key intermediate in antiretrovirol manufacture
- Gordon, Gregory Ernest Robert
- Authors: Gordon, Gregory Ernest Robert
- Date: 2010
- Subjects: HIV infections -- Treatment -- South Africa , HIV infections -- South Africa -- Prevention , Antiretroviral agents
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:10423 , http://hdl.handle.net/10948/d1016217
- Description: The socio-economic impact of HIV/AIDS on South Africa has resulted in lower gross domestic product, loss of skills in key sectors such as education, and increased health-care costs in providing access to treatment. Currently active pharmaceutical ingredients (API’s) such as stavudine (d4T) and azidothymidine (AZT) are imported from India and China, while formulation is conducted locally. A strategy was initiated between CSIR Biosciences and LIFElab under the auspices of Arvir Technologies to investigate the feasibility of local antiretroviral manufacture (d4T and AZT) or the manufacture of a key intermediate such as β- thymidine (dT). Several advantages associated with successful implementation of this strategy include ensuring a local supply of API’s, thus reducing reliance on procurement from foreign sources and reducing the effect of foreign exchange rate fluctuations on providing cost effective access to treatment. A local supply source would also reduce the imports and thus aid the balance of payments deficit, and in addition to this, provide stimulus in the local pharmaceutical manufacturing industry (which has been in decline for several decades), resulting in increased skills and employment opportunities. This thesis describes the development of a superior chemo-enzymatic process for the production of β-thymidine (72 percent yield, prior to isolation), a key intermediate in the preparation of anti-retrovirals. Alternative processes based purely on chemical or bioprocess transformations to prepare either 5-methyluridine (5-MU) or dT suffer from several disadvantages: lengthy transformations due to protection/deprotection strategies, low selectivties and product yields (30 percent in the chemical process) and isolation of the product from dilute process streams requiring the use of large uneconomical reactors (bioprocesss). This contributes significantly to the cost of d4T and AZT manufacture. Our novel chemoenzymatic process comprises of a biocatalytic reaction for the production of 5-MU, with subsequent chemical transformation into dT (3 steps) negating and circumventing the limitations of the chemical or bioprocess routes. During the course of this project development, the β-thymidine selling price declined from 175 $/kg (2005) to 100 $/kg (2008). However, the process described in this work is still competitive based on the current β- thymidine selling price of 100 $/kg. The process economics show that with further optimization and increasing the isolated dT yield from 70 percent to 90 percent, the variable cost decreases from 136 $/kg to 110 $/kg. The increase in isolated yield is highly probable, based on solubility data of β-thymidine. The decrease in β-thymidine selling price and technological improvement in dT manufacture should translate into lower API manufacture costs and more cost effective access to treatment. Our novel biocatalytic process producing 5-MU uses a coupled enzyme system employing PNP, Purine Nucleoside Phosphorylase and PyNP, Pyrimidine Nucleoside Phosphorylase. The overall transglycosylation reaction may be decoupled into the phosphorolysis reaction (PNP) and synthesis reaction (PyNP). During the phosphorolysis reaction, guanosine is converted into guanine and ribose-1-phosphate (R-1-P) in the presence of PNP enzyme. The reaction intermediate R-1-P is then coupled to thymine in the presence of PyNP enzyme during the synthesis reaction, producing 5-MU. The process was scaled up from lab-scale to bench-scale (10 - 20 L) and demonstrated to be robust and reproducible. This is evident from the average guanosine conversion (94.7 percent ± 2.03) and 5-MU yield (88.2 percent ± 6.21) and mole balance (104 percent ± 7.61) which were obtained at bench-scale (3 replicates, 10 L). The reaction was carried out at reactor productivities of between 7 – 11 g.L-1.h-1. The integration of the biocatalytic process and chemical processes was successfully carried out, showing that 5-MU produced using our novel biocatalytic process behaved similarly to commercially available 5- MU (ex. Dayang Chemicals, China). A PCT patent application (Ref. No. P44422PC01) on this chemo-enzymatic process has been filed and currently public private partnerships are being explored through Arvir Technologies to evaluate and validate this technology at one ton scale.
- Full Text:
- Date Issued: 2010
- Authors: Gordon, Gregory Ernest Robert
- Date: 2010
- Subjects: HIV infections -- Treatment -- South Africa , HIV infections -- South Africa -- Prevention , Antiretroviral agents
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:10423 , http://hdl.handle.net/10948/d1016217
- Description: The socio-economic impact of HIV/AIDS on South Africa has resulted in lower gross domestic product, loss of skills in key sectors such as education, and increased health-care costs in providing access to treatment. Currently active pharmaceutical ingredients (API’s) such as stavudine (d4T) and azidothymidine (AZT) are imported from India and China, while formulation is conducted locally. A strategy was initiated between CSIR Biosciences and LIFElab under the auspices of Arvir Technologies to investigate the feasibility of local antiretroviral manufacture (d4T and AZT) or the manufacture of a key intermediate such as β- thymidine (dT). Several advantages associated with successful implementation of this strategy include ensuring a local supply of API’s, thus reducing reliance on procurement from foreign sources and reducing the effect of foreign exchange rate fluctuations on providing cost effective access to treatment. A local supply source would also reduce the imports and thus aid the balance of payments deficit, and in addition to this, provide stimulus in the local pharmaceutical manufacturing industry (which has been in decline for several decades), resulting in increased skills and employment opportunities. This thesis describes the development of a superior chemo-enzymatic process for the production of β-thymidine (72 percent yield, prior to isolation), a key intermediate in the preparation of anti-retrovirals. Alternative processes based purely on chemical or bioprocess transformations to prepare either 5-methyluridine (5-MU) or dT suffer from several disadvantages: lengthy transformations due to protection/deprotection strategies, low selectivties and product yields (30 percent in the chemical process) and isolation of the product from dilute process streams requiring the use of large uneconomical reactors (bioprocesss). This contributes significantly to the cost of d4T and AZT manufacture. Our novel chemoenzymatic process comprises of a biocatalytic reaction for the production of 5-MU, with subsequent chemical transformation into dT (3 steps) negating and circumventing the limitations of the chemical or bioprocess routes. During the course of this project development, the β-thymidine selling price declined from 175 $/kg (2005) to 100 $/kg (2008). However, the process described in this work is still competitive based on the current β- thymidine selling price of 100 $/kg. The process economics show that with further optimization and increasing the isolated dT yield from 70 percent to 90 percent, the variable cost decreases from 136 $/kg to 110 $/kg. The increase in isolated yield is highly probable, based on solubility data of β-thymidine. The decrease in β-thymidine selling price and technological improvement in dT manufacture should translate into lower API manufacture costs and more cost effective access to treatment. Our novel biocatalytic process producing 5-MU uses a coupled enzyme system employing PNP, Purine Nucleoside Phosphorylase and PyNP, Pyrimidine Nucleoside Phosphorylase. The overall transglycosylation reaction may be decoupled into the phosphorolysis reaction (PNP) and synthesis reaction (PyNP). During the phosphorolysis reaction, guanosine is converted into guanine and ribose-1-phosphate (R-1-P) in the presence of PNP enzyme. The reaction intermediate R-1-P is then coupled to thymine in the presence of PyNP enzyme during the synthesis reaction, producing 5-MU. The process was scaled up from lab-scale to bench-scale (10 - 20 L) and demonstrated to be robust and reproducible. This is evident from the average guanosine conversion (94.7 percent ± 2.03) and 5-MU yield (88.2 percent ± 6.21) and mole balance (104 percent ± 7.61) which were obtained at bench-scale (3 replicates, 10 L). The reaction was carried out at reactor productivities of between 7 – 11 g.L-1.h-1. The integration of the biocatalytic process and chemical processes was successfully carried out, showing that 5-MU produced using our novel biocatalytic process behaved similarly to commercially available 5- MU (ex. Dayang Chemicals, China). A PCT patent application (Ref. No. P44422PC01) on this chemo-enzymatic process has been filed and currently public private partnerships are being explored through Arvir Technologies to evaluate and validate this technology at one ton scale.
- Full Text:
- Date Issued: 2010
MISSTEV : model for information security shared tacit espoused values
- Authors: Thomson, Kerry-Lynn
- Date: 2007
- Subjects: Computer security -- Management , Management information systems -- Security measures , Data protection
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:9787 , http://hdl.handle.net/10948/717 , Computer security -- Management , Management information systems -- Security measures , Data protection
- Description: One of the most critical assets in most organisations is information. It is often described as the lifeblood of an organisation. For this reason, it is vital that this asset is protected through sound information security practices. However, the incorrect and indifferent behaviour of employees often leads to information assets becoming vulnerable. Incorrect employee behaviour could have an extremely negative impact on the protection of information. An information security solution should be a fundamental component in most organisations. It is, however, possible for an organisation to have the most comprehensive physical and technical information security controls in place, but the operational controls, and associated employee behaviour, have not received much consideration. Therefore, the issue of employee behaviour must be addressed in an organisation to assist in ensuring the protection of information assets. The corporate culture of an organisation is largely responsible for the actions and behaviour of employees. Therefore, to address operational information security controls, the corporate culture of an organisation should be considered. To ensure the integration of information security into the corporate culture of an organisation, the protection of information should become part of the way the employees conduct their everyday tasks – from senior management, right throughout the entire organisation. Therefore, information security should become an integral component of the corporate culture of the organisation. To address the integration of information security into the corporate culture of an organisation, a model was developed which depicted the learning stages and modes of knowledge creation necessary to transform the corporate culture into one that is information security aware.
- Full Text:
- Date Issued: 2007
- Authors: Thomson, Kerry-Lynn
- Date: 2007
- Subjects: Computer security -- Management , Management information systems -- Security measures , Data protection
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:9787 , http://hdl.handle.net/10948/717 , Computer security -- Management , Management information systems -- Security measures , Data protection
- Description: One of the most critical assets in most organisations is information. It is often described as the lifeblood of an organisation. For this reason, it is vital that this asset is protected through sound information security practices. However, the incorrect and indifferent behaviour of employees often leads to information assets becoming vulnerable. Incorrect employee behaviour could have an extremely negative impact on the protection of information. An information security solution should be a fundamental component in most organisations. It is, however, possible for an organisation to have the most comprehensive physical and technical information security controls in place, but the operational controls, and associated employee behaviour, have not received much consideration. Therefore, the issue of employee behaviour must be addressed in an organisation to assist in ensuring the protection of information assets. The corporate culture of an organisation is largely responsible for the actions and behaviour of employees. Therefore, to address operational information security controls, the corporate culture of an organisation should be considered. To ensure the integration of information security into the corporate culture of an organisation, the protection of information should become part of the way the employees conduct their everyday tasks – from senior management, right throughout the entire organisation. Therefore, information security should become an integral component of the corporate culture of the organisation. To address the integration of information security into the corporate culture of an organisation, a model was developed which depicted the learning stages and modes of knowledge creation necessary to transform the corporate culture into one that is information security aware.
- Full Text:
- Date Issued: 2007
Causal determinants of the public's attitudes towards hunting as a basis for strategies to improve the social legitimacy of hunting
- Coetzer, Wentzel Christoffel
- Authors: Coetzer, Wentzel Christoffel
- Date: 2014
- Subjects: Hunting -- South Africa , Wildlife management -- South Africa , Wildlife conservation -- South Africa
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:10759 , http://hdl.handle.net/10948/d1021164
- Description: It is widely acknowledged that the organised wildlife and hunting industry in South Africa contributes significantly to the country’s economy, as well as to the effective management and conservation of wildlife on privately owned land. Despite this, hunting has come under increasing attack by anti-hunting proponents who wish to bring a ban on hunting. A number of broad shifts across society at large and lobbying against hunting by anti-hunting proponents have given rise to legitimate concerns regarding the social acceptability of hunting. To maintain the social legitimacy of hunting, it is imperative to put strategies in place to actively broaden the base of public acceptance of hunting. Towards this aim, this study is an empirical investigation of the causal determinants of the public’s attitudes towards hunting and of the implications it holds for improving the social legitimacy of hunting. The study commenced by building a sound theoretical foundation from the available literature on the measurement of attitudes, the structure and formation of attitudes, the instrumental and experiential aspects of attitudes, attitudinal ambivalence, the psychology of strong attitudes, as well as the phenomenon of cognitive dissonance. Thereafter, the study turned to identify an adequate and empirically valid research approach for investigating attitudes and its causal determinants. A popular attitude theory in social psychology, namely the theory of reasoned action, was identified as a suitable conceptual framework for conducting this study. According to the reasoned action model, the salient behavioural beliefs people associate with a particular behaviour form the informational foundation (or cognitive foundation) on which their attitudes towards the behaviour are based. More specifically, the model suggests that peoples’ overall attitude towards a behaviour is a function of their perceived probability that a behaviour will produce certain outcomes (belief strength), as well as the degree to which they judge the perceived outcomes of the behaviour as positive or negative (outcome evaluation). The methodological design of the study’s empirical component was strictly based on the standard procedures prescribed by the theory of reasoned action. Two consecutive and methodologically interrelated surveys were conducted amongst members of the public to collect the study’s primary data. The main salient behavioural beliefs on which different attitudes towards hunting are based were identified and further investigated. The results were analysed from the perspective of the theory of reasoned action and a clear understanding of the causal determinants of different attitudes towards hunting were attained. Based on the findings of the study, a number of conclusions and recommendations were made that may guide the development of future strategies to improve the social legitimacy of hunting. Amongst other things, it was suggested that public education programmes should be developed to address the public’s misconceptions of hunting; that public relation campaigns be undertaken to improve the public’s negative image of hunters; and that hunter education programmes be put in place to make hunters aware of the role they could play at community level to improve the social acceptability of hunting. Detailed guidelines regarding the contents of such education programmes and public relation campaigns were provided.
- Full Text:
- Date Issued: 2014
- Authors: Coetzer, Wentzel Christoffel
- Date: 2014
- Subjects: Hunting -- South Africa , Wildlife management -- South Africa , Wildlife conservation -- South Africa
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:10759 , http://hdl.handle.net/10948/d1021164
- Description: It is widely acknowledged that the organised wildlife and hunting industry in South Africa contributes significantly to the country’s economy, as well as to the effective management and conservation of wildlife on privately owned land. Despite this, hunting has come under increasing attack by anti-hunting proponents who wish to bring a ban on hunting. A number of broad shifts across society at large and lobbying against hunting by anti-hunting proponents have given rise to legitimate concerns regarding the social acceptability of hunting. To maintain the social legitimacy of hunting, it is imperative to put strategies in place to actively broaden the base of public acceptance of hunting. Towards this aim, this study is an empirical investigation of the causal determinants of the public’s attitudes towards hunting and of the implications it holds for improving the social legitimacy of hunting. The study commenced by building a sound theoretical foundation from the available literature on the measurement of attitudes, the structure and formation of attitudes, the instrumental and experiential aspects of attitudes, attitudinal ambivalence, the psychology of strong attitudes, as well as the phenomenon of cognitive dissonance. Thereafter, the study turned to identify an adequate and empirically valid research approach for investigating attitudes and its causal determinants. A popular attitude theory in social psychology, namely the theory of reasoned action, was identified as a suitable conceptual framework for conducting this study. According to the reasoned action model, the salient behavioural beliefs people associate with a particular behaviour form the informational foundation (or cognitive foundation) on which their attitudes towards the behaviour are based. More specifically, the model suggests that peoples’ overall attitude towards a behaviour is a function of their perceived probability that a behaviour will produce certain outcomes (belief strength), as well as the degree to which they judge the perceived outcomes of the behaviour as positive or negative (outcome evaluation). The methodological design of the study’s empirical component was strictly based on the standard procedures prescribed by the theory of reasoned action. Two consecutive and methodologically interrelated surveys were conducted amongst members of the public to collect the study’s primary data. The main salient behavioural beliefs on which different attitudes towards hunting are based were identified and further investigated. The results were analysed from the perspective of the theory of reasoned action and a clear understanding of the causal determinants of different attitudes towards hunting were attained. Based on the findings of the study, a number of conclusions and recommendations were made that may guide the development of future strategies to improve the social legitimacy of hunting. Amongst other things, it was suggested that public education programmes should be developed to address the public’s misconceptions of hunting; that public relation campaigns be undertaken to improve the public’s negative image of hunters; and that hunter education programmes be put in place to make hunters aware of the role they could play at community level to improve the social acceptability of hunting. Detailed guidelines regarding the contents of such education programmes and public relation campaigns were provided.
- Full Text:
- Date Issued: 2014
Characterisation of dissimilar friction stir welds between 5754 Aluminium alloy and C11000 copper
- Authors: Akinlabi, Esther Titilayo
- Date: 2010
- Subjects: Friction stir welding , Aluminum alloys , Copper alloys
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:9629 , http://hdl.handle.net/10948/1536 , Friction stir welding , Aluminum alloys , Copper alloys
- Description: Friction Stir Welding (FSW) is a solid state welding process invented and patented by The Welding Institute (TWI) in 1991, for joining ferrous and non-ferrous materials1. The FSW of Aluminium and its alloys has been commercialised; and recent interest is focused on joining dissimilar materials. However, in order to commercialise the process, research studies are required to characterise and establish process windows. This research work through material characterisation of the welded joints establishes a process window for the Friction Stir welding of 5754 Aluminium Alloy and C11000 Copper. Furthermore, preliminary studies83,85 on the FSW of aluminium and copper have revealed the presence of intermetallic compounds which are detrimental to the weld qualities. This research work is also aimed at establishing process parameters that will result in limited or no intermetallic formation in the weld. The joint integrity of the resulting welds will also be correlated with the input process parameters. Based on the preliminary investigations conducted, a final weld matrix consisting of twenty seven welds was produced by varying the rotational speed between 600 and 1200 rpm, and the feed rate between 50 and 300 mm/min using three different shoulder diameter tools – 15, 18 and 25 mm to compare the heat input into the welds and to achieve the best results. The welds were characterised through microstructural evaluation, tensile testing, microhardness profiling, X-Ray Diffraction analysis, electrical resistivity and statistical analysis – in order to establish the interrelationship between the process parameters and the weld qualities. viii Microstructural evaluation of the weld samples revealed that the interfacial regions are characterised by mixture layers of aluminium and copper; while 33 percent of the tensile samples are within the acceptable range (> 75 percent joint efficiency). High Vickers microhardness values were measured at the joint interfaces, which corresponded with the intermetallic compounds. The Energy Dispersive Spectroscopy analysis revealed the presence of thin layers of intermetallics in nanoscale at the interfacial regions. The diffractograms of the X-Ray Diffraction analysis showed small peaks for intermetallics in some of the welds. Low electrical resistivities were measured at the joint interfaces. The statistical analysis showed that the downward vertical force, (Fz) can significantly influence the resulting weld qualities. An overall summary of the analysis of the weld qualities - with respect to the shoulder diameter tools employed showed that the 18 mm shoulder diameter tool is most appropriate among the three shoulder diameters considered, and a process window of medium spindle speed of 950 rpm and low-to-medium feed rate between 50 and 150 mm/min is established for FSW of Aluminium and Copper. Welds produced at 1200 rpm and 300 mm/min with low heat input did not have intermetallics formed at the joint interface.
- Full Text:
- Date Issued: 2010
- Authors: Akinlabi, Esther Titilayo
- Date: 2010
- Subjects: Friction stir welding , Aluminum alloys , Copper alloys
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:9629 , http://hdl.handle.net/10948/1536 , Friction stir welding , Aluminum alloys , Copper alloys
- Description: Friction Stir Welding (FSW) is a solid state welding process invented and patented by The Welding Institute (TWI) in 1991, for joining ferrous and non-ferrous materials1. The FSW of Aluminium and its alloys has been commercialised; and recent interest is focused on joining dissimilar materials. However, in order to commercialise the process, research studies are required to characterise and establish process windows. This research work through material characterisation of the welded joints establishes a process window for the Friction Stir welding of 5754 Aluminium Alloy and C11000 Copper. Furthermore, preliminary studies83,85 on the FSW of aluminium and copper have revealed the presence of intermetallic compounds which are detrimental to the weld qualities. This research work is also aimed at establishing process parameters that will result in limited or no intermetallic formation in the weld. The joint integrity of the resulting welds will also be correlated with the input process parameters. Based on the preliminary investigations conducted, a final weld matrix consisting of twenty seven welds was produced by varying the rotational speed between 600 and 1200 rpm, and the feed rate between 50 and 300 mm/min using three different shoulder diameter tools – 15, 18 and 25 mm to compare the heat input into the welds and to achieve the best results. The welds were characterised through microstructural evaluation, tensile testing, microhardness profiling, X-Ray Diffraction analysis, electrical resistivity and statistical analysis – in order to establish the interrelationship between the process parameters and the weld qualities. viii Microstructural evaluation of the weld samples revealed that the interfacial regions are characterised by mixture layers of aluminium and copper; while 33 percent of the tensile samples are within the acceptable range (> 75 percent joint efficiency). High Vickers microhardness values were measured at the joint interfaces, which corresponded with the intermetallic compounds. The Energy Dispersive Spectroscopy analysis revealed the presence of thin layers of intermetallics in nanoscale at the interfacial regions. The diffractograms of the X-Ray Diffraction analysis showed small peaks for intermetallics in some of the welds. Low electrical resistivities were measured at the joint interfaces. The statistical analysis showed that the downward vertical force, (Fz) can significantly influence the resulting weld qualities. An overall summary of the analysis of the weld qualities - with respect to the shoulder diameter tools employed showed that the 18 mm shoulder diameter tool is most appropriate among the three shoulder diameters considered, and a process window of medium spindle speed of 950 rpm and low-to-medium feed rate between 50 and 150 mm/min is established for FSW of Aluminium and Copper. Welds produced at 1200 rpm and 300 mm/min with low heat input did not have intermetallics formed at the joint interface.
- Full Text:
- Date Issued: 2010
A critical analysis of organisational strategies for employee engagement
- Authors: Poisat, Paul
- Date: 2006
- Subjects: Employees -- Attitudes , Employee motivation , Personnel management
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:9378 , http://hdl.handle.net/10948/466 , Employees -- Attitudes , Employee motivation , Personnel management
- Description: Organisations are continuously searching for ways to increase their competitiveness as a means to survive in the global economy. More recently approaches have focused on the role that people perform in bringing about competitive advantage. Research indicates that engaged employees contribute vastly to the financial bottom-line of the organisation (see section 3.2.2). The research problem in this study was to identify strategies that organisations can use to engage their employees. To achieve this objective a theoretical employee engagement model was presented. The presentation of the theoretical model consisted of the following sub-processes: § Firstly, a literature survey was conducted to determine the underlying drivers/constructs of employee engagement. Abstract iii § The second comprised surveying the literature dealing specifically with approaches for measuring employee engagement. § Thirdly, the literature was surveyed to identify strategies and models used by organisations for engaging employees. The theoretical employee engagement model served as a basis for the compilation of the survey questionnaire that determined the extent to which human resource practitioners and line managers agree with the theoretical model developed in this study. The questionnaire was administered to a random sample of individuals employed in the automotive cluster in the Nelson Mandela Metropolitan Municipality and the Buffalo City Metropole. The empirical results obtained from the survey indicated that respondents strongly concurred with the theoretical employee engagement model presented in the study. These results were included in the theoretical model, which lead to the development of the integrated organisational employee engagement model. The model comprises of four interrelated categories that all contribute to enhancing employees’ engagement. These categories are organisational leadership, organisational culture, organisational strategies and the manager’s role. From the literature survey and the study it became clear that the role of the manager, had the most significant impact on employee engagement of all the categories. In addition, the integrated organisational employee engagement model can be used by organisations as an applied strategy for the measurement of employee engagement. The main findings from this research are that 60 per cent of organisations that participated in the empirical study had implemented strategies to engage their employees. However, the majority of organisations reporting not having an engagement strategy were among organisations that employed less than 700 employees (smaller organisations). The study also highlighted certain variables that required special attention, especially when implementing employee engagement within the South African context. South African companies as compared to their overseas counterparts, rated organisational engagement variables such as remuneration, benefits and gain sharing lower. A further variable that was identified by the study requiring special attention was, ‘senior management shows a sincere interest in employees’ well-being’. A final point emanating from the study is that the implementation of employee engagement, as a strategy to enhance organisational competitiveness, must be viewed as a continuous process. Organisations should prior, to the implementation of an employee engagement strategy, consider whether they are prepared to share engagement results, take corrective action commensurate with the results and deal with employee expectations that may be incurred. The strategies espoused by the integrated organisational employee engagement model developed in this study, can be used by organisations to increase organisational competitiveness by improving their employees’ level of engagement.
- Full Text:
- Date Issued: 2006
- Authors: Poisat, Paul
- Date: 2006
- Subjects: Employees -- Attitudes , Employee motivation , Personnel management
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:9378 , http://hdl.handle.net/10948/466 , Employees -- Attitudes , Employee motivation , Personnel management
- Description: Organisations are continuously searching for ways to increase their competitiveness as a means to survive in the global economy. More recently approaches have focused on the role that people perform in bringing about competitive advantage. Research indicates that engaged employees contribute vastly to the financial bottom-line of the organisation (see section 3.2.2). The research problem in this study was to identify strategies that organisations can use to engage their employees. To achieve this objective a theoretical employee engagement model was presented. The presentation of the theoretical model consisted of the following sub-processes: § Firstly, a literature survey was conducted to determine the underlying drivers/constructs of employee engagement. Abstract iii § The second comprised surveying the literature dealing specifically with approaches for measuring employee engagement. § Thirdly, the literature was surveyed to identify strategies and models used by organisations for engaging employees. The theoretical employee engagement model served as a basis for the compilation of the survey questionnaire that determined the extent to which human resource practitioners and line managers agree with the theoretical model developed in this study. The questionnaire was administered to a random sample of individuals employed in the automotive cluster in the Nelson Mandela Metropolitan Municipality and the Buffalo City Metropole. The empirical results obtained from the survey indicated that respondents strongly concurred with the theoretical employee engagement model presented in the study. These results were included in the theoretical model, which lead to the development of the integrated organisational employee engagement model. The model comprises of four interrelated categories that all contribute to enhancing employees’ engagement. These categories are organisational leadership, organisational culture, organisational strategies and the manager’s role. From the literature survey and the study it became clear that the role of the manager, had the most significant impact on employee engagement of all the categories. In addition, the integrated organisational employee engagement model can be used by organisations as an applied strategy for the measurement of employee engagement. The main findings from this research are that 60 per cent of organisations that participated in the empirical study had implemented strategies to engage their employees. However, the majority of organisations reporting not having an engagement strategy were among organisations that employed less than 700 employees (smaller organisations). The study also highlighted certain variables that required special attention, especially when implementing employee engagement within the South African context. South African companies as compared to their overseas counterparts, rated organisational engagement variables such as remuneration, benefits and gain sharing lower. A further variable that was identified by the study requiring special attention was, ‘senior management shows a sincere interest in employees’ well-being’. A final point emanating from the study is that the implementation of employee engagement, as a strategy to enhance organisational competitiveness, must be viewed as a continuous process. Organisations should prior, to the implementation of an employee engagement strategy, consider whether they are prepared to share engagement results, take corrective action commensurate with the results and deal with employee expectations that may be incurred. The strategies espoused by the integrated organisational employee engagement model developed in this study, can be used by organisations to increase organisational competitiveness by improving their employees’ level of engagement.
- Full Text:
- Date Issued: 2006
The development of a framework to reduce water and energy consumption through the use of water and energy value stream mapping for the South African manufacturing industry
- Authors: Davies, Edward
- Date: 2015
- Subjects: Lean manufacturing -- South Africa , Stream mapping -- South Africa , Water consumption -- South Africa
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: http://hdl.handle.net/10948/4160 , vital:20564
- Description: The Republic of South Africa’s energy economy is under immense pressure and the main energy utility, Eskom, cannot reliably generate sufficient electrical energy to meet its customer demand. Water security in South Africa is also under threat as the country is currently amidst a water crisis. The South African manufacturing industry is the sector consuming the largest portion of the total energy consumption and second largest portion of the total water consumption (excluding urban use) nationally. Water and energy efficiency improvement is becoming imperative for organisational success as well as national economic sustainability. This is due to the significant increase in the cost of both electrical energy and water in recent years, and the drop in the reserve energy margin below the minimum level required for sustainable operation of energy utilities. The research objective therefore was to develop a Lean-based water and energy efficiency improvement framework for the manufacturing industry to encourage and realise a reduced demand for energy and water in it. A literature review was conducted on the water and energy landscape in South Africa, Lean manufacturing principles and their positive natural influence on water and energy efficiency, and the Value Stream Mapping tool. The survey of water and energy wastes in the manufacturing industry yielded the creation of standardised water and energy waste categories for use in conjunction with the conventional Lean wastes, tools and techniques. The literature survey indicated that the implementation of Lean manufacturing techniques naturally leads to the improvement of energy and water intensity. The researcher hypothesised that there is even greater potential for water and energy savings if a Lean-based tool is developed to specifically focus on the improvement of energy and water efficiency. A framework for this tool was developed through the literature survey. The tool is based on the Value Stream Mapping tool. A practical experiment was then conducted to establish the effectiveness of the tool in the South African manufacturing industry. The experiment design included an outline of the forecasting and statistical validation techniques to ensure the integrity of data utilised for approving or disproving the set hypotheses. The results of the practical experiment yielded positive results, confirming the hypothesis that the implementation of the developed framework will lead to improved energy and water efficiency in the manufacturing industry. After an explanation of the experimental results, the study concluded with recommendations and conclusions based on the findings.
- Full Text:
- Date Issued: 2015
- Authors: Davies, Edward
- Date: 2015
- Subjects: Lean manufacturing -- South Africa , Stream mapping -- South Africa , Water consumption -- South Africa
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: http://hdl.handle.net/10948/4160 , vital:20564
- Description: The Republic of South Africa’s energy economy is under immense pressure and the main energy utility, Eskom, cannot reliably generate sufficient electrical energy to meet its customer demand. Water security in South Africa is also under threat as the country is currently amidst a water crisis. The South African manufacturing industry is the sector consuming the largest portion of the total energy consumption and second largest portion of the total water consumption (excluding urban use) nationally. Water and energy efficiency improvement is becoming imperative for organisational success as well as national economic sustainability. This is due to the significant increase in the cost of both electrical energy and water in recent years, and the drop in the reserve energy margin below the minimum level required for sustainable operation of energy utilities. The research objective therefore was to develop a Lean-based water and energy efficiency improvement framework for the manufacturing industry to encourage and realise a reduced demand for energy and water in it. A literature review was conducted on the water and energy landscape in South Africa, Lean manufacturing principles and their positive natural influence on water and energy efficiency, and the Value Stream Mapping tool. The survey of water and energy wastes in the manufacturing industry yielded the creation of standardised water and energy waste categories for use in conjunction with the conventional Lean wastes, tools and techniques. The literature survey indicated that the implementation of Lean manufacturing techniques naturally leads to the improvement of energy and water intensity. The researcher hypothesised that there is even greater potential for water and energy savings if a Lean-based tool is developed to specifically focus on the improvement of energy and water efficiency. A framework for this tool was developed through the literature survey. The tool is based on the Value Stream Mapping tool. A practical experiment was then conducted to establish the effectiveness of the tool in the South African manufacturing industry. The experiment design included an outline of the forecasting and statistical validation techniques to ensure the integrity of data utilised for approving or disproving the set hypotheses. The results of the practical experiment yielded positive results, confirming the hypothesis that the implementation of the developed framework will lead to improved energy and water efficiency in the manufacturing industry. After an explanation of the experimental results, the study concluded with recommendations and conclusions based on the findings.
- Full Text:
- Date Issued: 2015
Tailoring a lean product development framework for the South African automotive industry
- Authors: Mund, Klaudia
- Date: 2011
- Subjects: Lean manufacturing , Automobile industry and trade -- South Africa , Production management -- South Africa , Globalization
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:8792 , http://hdl.handle.net/10948/d1015737
- Description: Globalization in the automotive industry exerts enormous pressure on automotive manufacturers and forces many global companies to expand into emerging markets, which results in adopting new ways to manage product design and development. Excellence in product design and development offers an opportunity to gain competitive advantage and can be achieved by implementing Toyota´s Lean Product Development System (LPDS). Although in the last three years Toyota has been severely challenged by the global economic crisis, by a series of recalls resulting in reputation damage and also by natural disasters such as the recent tsunamis - the world can still learn from Toyota´s successes embodied in the lean concept and practices, which are integral to Toyota´s ‘way of life’. The LPDS model (Morgan & Liker 2006) has captured the attention of academics worldwide (including this researcher) thanks to the following key characteristics: shorter development times, less engineering hours involved in development, lower manufacturing costs, higher customer satisfaction and fewer defects reported. In the academic world, lean product development (LPD) is a new field of exploration and thus relevant literature and numbers of studies available are limited. However, scientists are asking questions about successful adaptation and adoption of this model to other environments beyond Toyota. Similarly, the researcher aimed in this thesis to find answers to its main research question, namely: ‘What would be a suitable LPD model for the South African automotive industry?’ South Africa (SA) is a country with a strong manufacturing tradition and although the automotive sector is the third-largest segment in the South African economy and its vehicle market is the largest on the African continent in a global perspective SA´s contribution is relatively small as it produces only 0.61percent of the global motor vehicle volume (OICA 2011). While the country strives to secure sustainable development for the automotive industry and seeks to improve its global competitiveness, companies operating in SA are currently faced with several unique challenges and problems. Lean has been expanding slowly in SA and some companies in the local automotive industry have implemented the lean concept into production areas to improve their operational excellence and performance. However, it is a search for excellence in product development (PD) that could best contribute to improved sustainability for the automotive industry and also provide an important strategic spur towards global competitiveness. The primary intention of this research was to develop an integrated LPD framework tailored for SA´s automotive industry. Considering this, it was necessary to determine current PD capabilities at domestic and international companies operating in SA´s automotive industry so as to examine levels of adaptation of LPD practices. A questionnaire survey and personal interviews involving all seven locally operating Original Equipment Manufacturers (OEMs), including Toyota, as well as 36 local automotive suppliers provided an empirical base for this investigation. This study indicates that SA plays an important supportive role in the global PD context. In spite of a strong manufacturing focus and very limited PD capabilities, SA´s automotive companies have already achieved a high level of ‘leanness’ in product engineering processes. However, on the downside, it appears that industry leaders and senior managers are sceptical about current and future capabilities and opportunities for SA in the designing and developing of global products.
- Full Text:
- Date Issued: 2011
- Authors: Mund, Klaudia
- Date: 2011
- Subjects: Lean manufacturing , Automobile industry and trade -- South Africa , Production management -- South Africa , Globalization
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:8792 , http://hdl.handle.net/10948/d1015737
- Description: Globalization in the automotive industry exerts enormous pressure on automotive manufacturers and forces many global companies to expand into emerging markets, which results in adopting new ways to manage product design and development. Excellence in product design and development offers an opportunity to gain competitive advantage and can be achieved by implementing Toyota´s Lean Product Development System (LPDS). Although in the last three years Toyota has been severely challenged by the global economic crisis, by a series of recalls resulting in reputation damage and also by natural disasters such as the recent tsunamis - the world can still learn from Toyota´s successes embodied in the lean concept and practices, which are integral to Toyota´s ‘way of life’. The LPDS model (Morgan & Liker 2006) has captured the attention of academics worldwide (including this researcher) thanks to the following key characteristics: shorter development times, less engineering hours involved in development, lower manufacturing costs, higher customer satisfaction and fewer defects reported. In the academic world, lean product development (LPD) is a new field of exploration and thus relevant literature and numbers of studies available are limited. However, scientists are asking questions about successful adaptation and adoption of this model to other environments beyond Toyota. Similarly, the researcher aimed in this thesis to find answers to its main research question, namely: ‘What would be a suitable LPD model for the South African automotive industry?’ South Africa (SA) is a country with a strong manufacturing tradition and although the automotive sector is the third-largest segment in the South African economy and its vehicle market is the largest on the African continent in a global perspective SA´s contribution is relatively small as it produces only 0.61percent of the global motor vehicle volume (OICA 2011). While the country strives to secure sustainable development for the automotive industry and seeks to improve its global competitiveness, companies operating in SA are currently faced with several unique challenges and problems. Lean has been expanding slowly in SA and some companies in the local automotive industry have implemented the lean concept into production areas to improve their operational excellence and performance. However, it is a search for excellence in product development (PD) that could best contribute to improved sustainability for the automotive industry and also provide an important strategic spur towards global competitiveness. The primary intention of this research was to develop an integrated LPD framework tailored for SA´s automotive industry. Considering this, it was necessary to determine current PD capabilities at domestic and international companies operating in SA´s automotive industry so as to examine levels of adaptation of LPD practices. A questionnaire survey and personal interviews involving all seven locally operating Original Equipment Manufacturers (OEMs), including Toyota, as well as 36 local automotive suppliers provided an empirical base for this investigation. This study indicates that SA plays an important supportive role in the global PD context. In spite of a strong manufacturing focus and very limited PD capabilities, SA´s automotive companies have already achieved a high level of ‘leanness’ in product engineering processes. However, on the downside, it appears that industry leaders and senior managers are sceptical about current and future capabilities and opportunities for SA in the designing and developing of global products.
- Full Text:
- Date Issued: 2011
Development of a process for the preparation of linalool from CIS-2-pinanol
- Authors: Buddoo, Subash Ramnarain
- Date: 2009
- Subjects: Odors , Perfumes -- History , Perfumes -- Formulae , Fermentation
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:10425 , http://hdl.handle.net/10948/d1016219
- Description: Linalool is a key intermediate for the production of important fragrance chemicals such as geraniol, nerol, geranial, and neral. Linalool can be produced via a two-step process from α-pinene which is a major component of crude sulphated turpentine (CST) a foul-smelling, volatile waste product of the pulp and paper industry. The key step in this process is the pyrolysis step which involves the isomerisation of cis-2-pinanol to linalool and requires high temperatures (600-650°C) and is not very selective due to the decomposition of the product itself under these conditions. A client of the CSIR, Teubes Pty. Ltd., is a manufacturer of flavour and fragrance compounds for the local and international fragrance market and expressed an interest in producing linalool since the company would then gain access to other valuable fragrance chemicals via relatively simple processes. Earlier work conducted by AECI, R & D did not meet with much success since the selectivity to linalool was very poor and the process could hardly be deemed as scalable. The main objective of this project was therefore to develop a process for the selective isomerisation of cis-2-pinanol to linalool with minimum by-product formation and using process equipment that could be scaled to full-scale production. Since cis-2- pinanol could not be purchased in sufficient quantities for process development, a process had to be developed for the bench-scale preparation of kilogram quantities of cis-2-pinanol from α-pinene obtained from the client. Although this synthesis formed a minor part of this investigation, several process improvements and innovations were introduced to produce high quality cis-2-pinanol, in very good yields at kilogram scale. A major part of this investigation was the design and set up of a pyrolyis rig capable of operating at elevated temperatures (400 - 750°C) for the evaluation of various process parameters. Various vaporizer, reactor, and condensation systems were evaluated for their ability to cope with the demanding conditions on a consistent basis. The initial part of the investigation was a screening exercise to evaluate various process parameters as well as solvents, materials of construction, catalysts, etc. A comprehensive statistical design was also conducted to determine the critical process parameters and the model obtained was used to predict the optimum conditions required for the preparation of in-specification product on a consistent basis. These conditions were used in the preparation of a 1kg sample which was required by theclient for market evaluation purposes. The use of a novel microreactor system was also evaluated for the pinanol pyrolysis reaction. To our knowledge, this is the first time that a microreactor has been successfully used for this type of reaction in the Fragrance industry and a patent application is being filed by the CSIR. The kinetics of the reaction in both the tubular reactor system and the microreactor system was investigated. Computer modelling studies on both the systems were also conducted. The raw material cost to produce a kilogram of linalool is $1.40. There is a significant margin of 60.8 percent between the raw material cost of linalool and the current selling price ($3.57/kg). This clearly indicates that the project is potentially feasible from an economic point of view and we can now proceed with confidence to the next stage which is the engineering design, building and commissioning of the large scale pyrolysis rig. The rest of the process steps will be conducted on existing equipment currently present at the CSIR’s large scale facility (Imbiza in Isando, Gauteng).
- Full Text:
- Date Issued: 2009
- Authors: Buddoo, Subash Ramnarain
- Date: 2009
- Subjects: Odors , Perfumes -- History , Perfumes -- Formulae , Fermentation
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:10425 , http://hdl.handle.net/10948/d1016219
- Description: Linalool is a key intermediate for the production of important fragrance chemicals such as geraniol, nerol, geranial, and neral. Linalool can be produced via a two-step process from α-pinene which is a major component of crude sulphated turpentine (CST) a foul-smelling, volatile waste product of the pulp and paper industry. The key step in this process is the pyrolysis step which involves the isomerisation of cis-2-pinanol to linalool and requires high temperatures (600-650°C) and is not very selective due to the decomposition of the product itself under these conditions. A client of the CSIR, Teubes Pty. Ltd., is a manufacturer of flavour and fragrance compounds for the local and international fragrance market and expressed an interest in producing linalool since the company would then gain access to other valuable fragrance chemicals via relatively simple processes. Earlier work conducted by AECI, R & D did not meet with much success since the selectivity to linalool was very poor and the process could hardly be deemed as scalable. The main objective of this project was therefore to develop a process for the selective isomerisation of cis-2-pinanol to linalool with minimum by-product formation and using process equipment that could be scaled to full-scale production. Since cis-2- pinanol could not be purchased in sufficient quantities for process development, a process had to be developed for the bench-scale preparation of kilogram quantities of cis-2-pinanol from α-pinene obtained from the client. Although this synthesis formed a minor part of this investigation, several process improvements and innovations were introduced to produce high quality cis-2-pinanol, in very good yields at kilogram scale. A major part of this investigation was the design and set up of a pyrolyis rig capable of operating at elevated temperatures (400 - 750°C) for the evaluation of various process parameters. Various vaporizer, reactor, and condensation systems were evaluated for their ability to cope with the demanding conditions on a consistent basis. The initial part of the investigation was a screening exercise to evaluate various process parameters as well as solvents, materials of construction, catalysts, etc. A comprehensive statistical design was also conducted to determine the critical process parameters and the model obtained was used to predict the optimum conditions required for the preparation of in-specification product on a consistent basis. These conditions were used in the preparation of a 1kg sample which was required by theclient for market evaluation purposes. The use of a novel microreactor system was also evaluated for the pinanol pyrolysis reaction. To our knowledge, this is the first time that a microreactor has been successfully used for this type of reaction in the Fragrance industry and a patent application is being filed by the CSIR. The kinetics of the reaction in both the tubular reactor system and the microreactor system was investigated. Computer modelling studies on both the systems were also conducted. The raw material cost to produce a kilogram of linalool is $1.40. There is a significant margin of 60.8 percent between the raw material cost of linalool and the current selling price ($3.57/kg). This clearly indicates that the project is potentially feasible from an economic point of view and we can now proceed with confidence to the next stage which is the engineering design, building and commissioning of the large scale pyrolysis rig. The rest of the process steps will be conducted on existing equipment currently present at the CSIR’s large scale facility (Imbiza in Isando, Gauteng).
- Full Text:
- Date Issued: 2009
Product development as part of a positioning strategy for the hunting industry in the Eastern Cape
- Van Niekerk, Pieter du Preez
- Authors: Van Niekerk, Pieter du Preez
- Date: 2002
- Subjects: New products -- Marketing , Hunting -- South Africa -- Eastern Cape , Game farms -- South Africa -- Eastern Cape , Venison -- Marketing , Meat industry and trade -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:10894 , http://hdl.handle.net/10948/111 , New products -- Marketing , Hunting -- South Africa -- Eastern Cape , Game farms -- South Africa -- Eastern Cape , Venison -- Marketing , Meat industry and trade -- South Africa -- Eastern Cape
- Description: In this study on product development and positioning in the hunting industry in the Eastern Cape, two conceptual frameworks were developed, based on a literature study. These positioning and product development concepts were tested against primary and secondary information gathered about the hunting industry. The game and hunting industries were in a strong growth phase at the time of this study. These industries are playing an increasingly important role in the economy of the Eastern Cape, and more and more agricultural land is utilised for game ranching. From the perspective of obtaining a competitive advantage in an increasingly competitive environment, it is therefore important for hunting providers to develop suitable products, and to position these products correctly. It is also important to investigate the characteristics of the game and hunting industries in the Eastern Cape and to get information about the characteristics of the market in which product development and positioning take place. Hunting is the most important form of game utilisation in the Eastern Cape, followed by cropping of game and live game sales. At the time of this study, the total value of the game utilised annually in the Eastern Cape was in excess of R168 million. Game utilisation seemed to be taking place on a sustainable basis, as the number of animals utilised annually was less than the annual production. Kudu and springbok provide the biggest total income, and, together with mountain reedbuck, are the most abundant species in the Eastern Cape. The main game-producing areas in the Eastern Cape coincide with the areas where extensive beef, sheep and goat farming are practised. The hunting products on offer from hunting providers, differ in certain ways. Aspects like price, type of hunting provided, game species available for hunting, terrain where hunting takes place, and various other aspects in connection with the hunt, differ from hunting provider to hunting provider. Characteristics of the hunting experience that hunters desire may be divided into core and variable elements. The core elements include: · the conditions pertaining to the hunt being spelt out clearly; · the maintenance of safety standards; · reasonable day fees; · the presence of game in sufficient numbers; and · other aspects generally desired by hunters. In the study it was found that the needs of hunters also differ regarding certain aspects of the hunting experience. These variable elements include price levels, type and availability of accommodation, and the role of the hunting provider. The core aspects that hunters desire are as a rule part of the product offering. From a product development perspective, the variable elements provide an opportunity to customise products to hunter needs. The inclusion or exclusion of variable elements from the product offering give rise to certain unique product features, and therefore provide the opportunity for product differentiation. After development, products are positioned firstly by selecting a market segment to focus on. Secondly, the needs of hunters in the target segment should be clearly identified, followed by the development of suitable products based on hunter needs, and taking into account the features of competitive offerings. Decisions should also be taken about the features to be included in the product offering to achieve product differentiation. After development of a suitable product, an image or brand should be chosen for the product, and this image should be effectively communicated to the market. A number of possible positioning options were identified for hunting providers. It was found that factors like the physical features of the ranch, available infrastructure, the market segment chosen, desires of the hunting providers, and the perception of the needs of hunters, eventually influence decisions about product development and positioning. The final decisions on positioning should take the core competencies of the hunting provider into account and should ensure that the hunting provider has the ability to fill the chosen position in the market.
- Full Text:
- Date Issued: 2002
- Authors: Van Niekerk, Pieter du Preez
- Date: 2002
- Subjects: New products -- Marketing , Hunting -- South Africa -- Eastern Cape , Game farms -- South Africa -- Eastern Cape , Venison -- Marketing , Meat industry and trade -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:10894 , http://hdl.handle.net/10948/111 , New products -- Marketing , Hunting -- South Africa -- Eastern Cape , Game farms -- South Africa -- Eastern Cape , Venison -- Marketing , Meat industry and trade -- South Africa -- Eastern Cape
- Description: In this study on product development and positioning in the hunting industry in the Eastern Cape, two conceptual frameworks were developed, based on a literature study. These positioning and product development concepts were tested against primary and secondary information gathered about the hunting industry. The game and hunting industries were in a strong growth phase at the time of this study. These industries are playing an increasingly important role in the economy of the Eastern Cape, and more and more agricultural land is utilised for game ranching. From the perspective of obtaining a competitive advantage in an increasingly competitive environment, it is therefore important for hunting providers to develop suitable products, and to position these products correctly. It is also important to investigate the characteristics of the game and hunting industries in the Eastern Cape and to get information about the characteristics of the market in which product development and positioning take place. Hunting is the most important form of game utilisation in the Eastern Cape, followed by cropping of game and live game sales. At the time of this study, the total value of the game utilised annually in the Eastern Cape was in excess of R168 million. Game utilisation seemed to be taking place on a sustainable basis, as the number of animals utilised annually was less than the annual production. Kudu and springbok provide the biggest total income, and, together with mountain reedbuck, are the most abundant species in the Eastern Cape. The main game-producing areas in the Eastern Cape coincide with the areas where extensive beef, sheep and goat farming are practised. The hunting products on offer from hunting providers, differ in certain ways. Aspects like price, type of hunting provided, game species available for hunting, terrain where hunting takes place, and various other aspects in connection with the hunt, differ from hunting provider to hunting provider. Characteristics of the hunting experience that hunters desire may be divided into core and variable elements. The core elements include: · the conditions pertaining to the hunt being spelt out clearly; · the maintenance of safety standards; · reasonable day fees; · the presence of game in sufficient numbers; and · other aspects generally desired by hunters. In the study it was found that the needs of hunters also differ regarding certain aspects of the hunting experience. These variable elements include price levels, type and availability of accommodation, and the role of the hunting provider. The core aspects that hunters desire are as a rule part of the product offering. From a product development perspective, the variable elements provide an opportunity to customise products to hunter needs. The inclusion or exclusion of variable elements from the product offering give rise to certain unique product features, and therefore provide the opportunity for product differentiation. After development, products are positioned firstly by selecting a market segment to focus on. Secondly, the needs of hunters in the target segment should be clearly identified, followed by the development of suitable products based on hunter needs, and taking into account the features of competitive offerings. Decisions should also be taken about the features to be included in the product offering to achieve product differentiation. After development of a suitable product, an image or brand should be chosen for the product, and this image should be effectively communicated to the market. A number of possible positioning options were identified for hunting providers. It was found that factors like the physical features of the ranch, available infrastructure, the market segment chosen, desires of the hunting providers, and the perception of the needs of hunters, eventually influence decisions about product development and positioning. The final decisions on positioning should take the core competencies of the hunting provider into account and should ensure that the hunting provider has the ability to fill the chosen position in the market.
- Full Text:
- Date Issued: 2002
The selective dechlorination of poly-chlorophenols
- Authors: Thomas, Maxwell Paul
- Date: 2009
- Subjects: Sewage -- Purification -- Chlorination , Pesticides -- Toxicology , Chlorine -- Toxicology
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:10391 , http://hdl.handle.net/10948/1124 , Sewage -- Purification -- Chlorination , Pesticides -- Toxicology , Chlorine -- Toxicology
- Description: Liquid phase catalytic hydrodechlorinations can provide a convenient and environmentally friendly method for treating organic chlorinated compounds in waste streams generated during the manufacturing of agrochemicals. During such treatment hydrochloric acid is generated as a by-product, which can be easily neutralized employing a base to yield an inorganic salt. This work describes the results obtained during the liquid phase hydrodechlorination of 2,6-dichlorophenol (2,6-DCP) and 2,4,6-trichlorophenol (2,4,6-TCP). The hydrodechlorination of these chlorinated phenolic compounds in a mixture of methanol and water was investigated using supported and unsupported palladium catalysts to yield lower chlorinated phenols or phenol. Various parameters were investigated such as catalyst concentration, ammonium formate concentration, effect of base addition and effect of temperature. During this study two methods of hydrodechlorination were also investigated such as hydride-transfer hydrogenolysis, using ammonium formate, and hydrogenolysis, using dihydrogen. These methods offer a mild treatment in terms of the reaction temperature with temperatures used below 800C. A comparison of the palladium catalyst systems using these methods also showed that Pd/C produced the best results in terms of the hydrodechlorination rate and the selectivity towards phenol. When the ammonium formate method was used, complete hydrodechlorination of both substrates was achieved in 1h of reaction time at a selectivity of 100 percent towards phenol. A comparison of the method using dihydrogen and Pd/C showed that the reaction rate and the selectivity towards phenol during the hydrodechlorination of 2,6-DCP were 87.92 percent and 93.30 percent. Similarly, the reaction rate and selectivity during 2,4,6- TCP hydrodechlorination were 63.77 percent and 70.57 percent. These results were achieved in a reaction time of 3 hours. A high catalyst loading increases the reaction rate at the expense of selectivity, due to the formation of cyclohexanone, formed during further hydrogenation of phenol. The formation of cyclohexanone was limited at high temperatures (ca. 800C) with none detected during the hydrodechlorination of 2,6-DCP and 0.19 percent during the hydrodechlorination of 2,4,6-TCP. Evaluation of the hydrodechlorination parameters showed that the catalytic efficiency of the Pd/C catalysts was inhibited as the reaction proceeded due to the formation of HCl as by-product. A significant increase in the reaction rate was achieved when the reaction was performed in the presence of an inorganic base, which neutralized HCl.
- Full Text:
- Date Issued: 2009
- Authors: Thomas, Maxwell Paul
- Date: 2009
- Subjects: Sewage -- Purification -- Chlorination , Pesticides -- Toxicology , Chlorine -- Toxicology
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:10391 , http://hdl.handle.net/10948/1124 , Sewage -- Purification -- Chlorination , Pesticides -- Toxicology , Chlorine -- Toxicology
- Description: Liquid phase catalytic hydrodechlorinations can provide a convenient and environmentally friendly method for treating organic chlorinated compounds in waste streams generated during the manufacturing of agrochemicals. During such treatment hydrochloric acid is generated as a by-product, which can be easily neutralized employing a base to yield an inorganic salt. This work describes the results obtained during the liquid phase hydrodechlorination of 2,6-dichlorophenol (2,6-DCP) and 2,4,6-trichlorophenol (2,4,6-TCP). The hydrodechlorination of these chlorinated phenolic compounds in a mixture of methanol and water was investigated using supported and unsupported palladium catalysts to yield lower chlorinated phenols or phenol. Various parameters were investigated such as catalyst concentration, ammonium formate concentration, effect of base addition and effect of temperature. During this study two methods of hydrodechlorination were also investigated such as hydride-transfer hydrogenolysis, using ammonium formate, and hydrogenolysis, using dihydrogen. These methods offer a mild treatment in terms of the reaction temperature with temperatures used below 800C. A comparison of the palladium catalyst systems using these methods also showed that Pd/C produced the best results in terms of the hydrodechlorination rate and the selectivity towards phenol. When the ammonium formate method was used, complete hydrodechlorination of both substrates was achieved in 1h of reaction time at a selectivity of 100 percent towards phenol. A comparison of the method using dihydrogen and Pd/C showed that the reaction rate and the selectivity towards phenol during the hydrodechlorination of 2,6-DCP were 87.92 percent and 93.30 percent. Similarly, the reaction rate and selectivity during 2,4,6- TCP hydrodechlorination were 63.77 percent and 70.57 percent. These results were achieved in a reaction time of 3 hours. A high catalyst loading increases the reaction rate at the expense of selectivity, due to the formation of cyclohexanone, formed during further hydrogenation of phenol. The formation of cyclohexanone was limited at high temperatures (ca. 800C) with none detected during the hydrodechlorination of 2,6-DCP and 0.19 percent during the hydrodechlorination of 2,4,6-TCP. Evaluation of the hydrodechlorination parameters showed that the catalytic efficiency of the Pd/C catalysts was inhibited as the reaction proceeded due to the formation of HCl as by-product. A significant increase in the reaction rate was achieved when the reaction was performed in the presence of an inorganic base, which neutralized HCl.
- Full Text:
- Date Issued: 2009
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
Analysis processes as antecedents for decision-making related to growth strategies of South African Game Ranchers
- Authors: Van Eyk, Marlé
- Date: 2010
- Subjects: Tourism -- Marketing , Game farms -- South Africa
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:9356 , http://hdl.handle.net/10948/1546 , Tourism -- Marketing , Game farms -- South Africa
- Description: Game ranching offers an economic alternative to conventional stock farming and is a means of supplementing income derived from agricultural activities. Competition is intensifying as ranchers continuously look for ways to improve and expand their businesses and gain a competitive advantage. Ranchers consequently have to find strategies that can ensure growth. Since a reciprocal relationship and dependency exists between a game ranch and the environment in which it operates, it is essential that ranchers take cognizance of aspects in the marketing environment that can either limit, and hence encumber the choice of growth strategy, or stimulate the growth potential of game ranches. As the objective of marketing is to offer customers superior value, it is pertinent for ranchers to know and understand the needs, requirements and motivations of visitors. Failure to do so will cause visitors to patronise other game ranches, or alternative tourism offerings that meet their expectations. A literature review was conducted to define strategy and assist in identifying growth strategies available to a game ranch. The literature review assisted in categorising elements in the external, internal and customer analysis phases of strategic marketing management. Surveys were conducted by means of self-completion questionnaires which were distributed throughout South Africa. Two sets of questionnaires were distributed - one to respondents with prior experience of a game ranch, and one to respondents with no-prior experience. A qualifying question directed the fieldworker to decide which questionnaire should be completed by the respondent. The surveys were constructed in such a way as to determine to what extent various factors would persuade respondents to visit a ranch or extend their stay. Based on a factor analysis, an eight factor structure emerged which represented the personal values of respondents and their levels of expectation for each of the factors. The eight factors were stimulation, universalism, tradition, security, hedonism, power, socialisation, and self-direction. The study revealed the following. - The majority of respondents with no-prior experience of a game ranch is either unaware of the offerings of game ranches, or perceives them as too expensive. - The sustainable use of natural resources is not only essential for the existence of a game ranch, but is also an important motivator for respondents to either visit a game ranch or extend their stay at a ranch. - Staff play a critical role in the overall experience of visitors and act as an important motivator to either visit/revisit a game ranch or extend their stay at the ranch. - Clean and comfortable overnight facilities are deemed important by all respondents. - Respondents have a strong desire to relax and spend time with family and friends. A decision-making framework from which game ranches can select applicable growth strategies resulted from the study. The decision-making framework comprises a three-phase process; phase 1 is the identification of a game ranch's target market; phase 2 is the use of a simplistic framework to determine a possible growth strategy for a game ranch; phase 3 is the identification of ways to implement the selected strategy. As the game ranch industry makes significant contributions to the economic, social and ecological welfare of South Africa, this study added to the body of knowledge of game ranching in South Africa, particularly with regard to the growth options available to game ranches. Recommendations for consideration of future research included the following. - As the current study investigated hunting and tourism, future research on growth strategies for game ranches could also include other aspects of game ranching such as the sale of live game and game products. - More focused empirical research into external and internal strategic analysis should be considered to supplement the empirical research into customer analysis resulting from the current study. - Finally, additional information obtained on the external and internal strategic analysis process could lead to expanding the decision-making framework developed in this study into a more holistic tool to be used in selecting a growth strategy, or combination of strategies for a game ranch3.
- Full Text:
- Date Issued: 2010
- Authors: Van Eyk, Marlé
- Date: 2010
- Subjects: Tourism -- Marketing , Game farms -- South Africa
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:9356 , http://hdl.handle.net/10948/1546 , Tourism -- Marketing , Game farms -- South Africa
- Description: Game ranching offers an economic alternative to conventional stock farming and is a means of supplementing income derived from agricultural activities. Competition is intensifying as ranchers continuously look for ways to improve and expand their businesses and gain a competitive advantage. Ranchers consequently have to find strategies that can ensure growth. Since a reciprocal relationship and dependency exists between a game ranch and the environment in which it operates, it is essential that ranchers take cognizance of aspects in the marketing environment that can either limit, and hence encumber the choice of growth strategy, or stimulate the growth potential of game ranches. As the objective of marketing is to offer customers superior value, it is pertinent for ranchers to know and understand the needs, requirements and motivations of visitors. Failure to do so will cause visitors to patronise other game ranches, or alternative tourism offerings that meet their expectations. A literature review was conducted to define strategy and assist in identifying growth strategies available to a game ranch. The literature review assisted in categorising elements in the external, internal and customer analysis phases of strategic marketing management. Surveys were conducted by means of self-completion questionnaires which were distributed throughout South Africa. Two sets of questionnaires were distributed - one to respondents with prior experience of a game ranch, and one to respondents with no-prior experience. A qualifying question directed the fieldworker to decide which questionnaire should be completed by the respondent. The surveys were constructed in such a way as to determine to what extent various factors would persuade respondents to visit a ranch or extend their stay. Based on a factor analysis, an eight factor structure emerged which represented the personal values of respondents and their levels of expectation for each of the factors. The eight factors were stimulation, universalism, tradition, security, hedonism, power, socialisation, and self-direction. The study revealed the following. - The majority of respondents with no-prior experience of a game ranch is either unaware of the offerings of game ranches, or perceives them as too expensive. - The sustainable use of natural resources is not only essential for the existence of a game ranch, but is also an important motivator for respondents to either visit a game ranch or extend their stay at a ranch. - Staff play a critical role in the overall experience of visitors and act as an important motivator to either visit/revisit a game ranch or extend their stay at the ranch. - Clean and comfortable overnight facilities are deemed important by all respondents. - Respondents have a strong desire to relax and spend time with family and friends. A decision-making framework from which game ranches can select applicable growth strategies resulted from the study. The decision-making framework comprises a three-phase process; phase 1 is the identification of a game ranch's target market; phase 2 is the use of a simplistic framework to determine a possible growth strategy for a game ranch; phase 3 is the identification of ways to implement the selected strategy. As the game ranch industry makes significant contributions to the economic, social and ecological welfare of South Africa, this study added to the body of knowledge of game ranching in South Africa, particularly with regard to the growth options available to game ranches. Recommendations for consideration of future research included the following. - As the current study investigated hunting and tourism, future research on growth strategies for game ranches could also include other aspects of game ranching such as the sale of live game and game products. - More focused empirical research into external and internal strategic analysis should be considered to supplement the empirical research into customer analysis resulting from the current study. - Finally, additional information obtained on the external and internal strategic analysis process could lead to expanding the decision-making framework developed in this study into a more holistic tool to be used in selecting a growth strategy, or combination of strategies for a game ranch3.
- Full Text:
- Date Issued: 2010
The development of a self-disintegrating core-body for use in an art bronze-casting foundry which employs the ceramic-shell investment technique
- Authors: Lomax, Lawrence Talbot
- Date: 2004
- Subjects: Sculpture -- Technique , Bronze founding , Precision casting , Shell molding (Founding)
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:8499 , http://hdl.handle.net/10948/219 , Sculpture -- Technique , Bronze founding , Precision casting , Shell molding (Founding)
- Description: The development of a disintegrating core-body for use in an art bronze foundry, which employs the ceramic shell investment process, begins with an investigation of four principal materials that will constitute the core formula. The specifications for the disintegration of the designed core-body formula fall within the parameters that are normally set and used in the ceramic shell art bronze casting process. The raison d’ être for the disintegrating formula is based on the premise that cement breaks down (spalling) after being subjected to heat above a certain temperature. It was shown that pure cement in the form of naked test bars 100 mm x 20 mm x 20 mm does indeed break down into separate pieces when fired to and above 9000C; where 9000C is the lowest recommended temperature required for sintering the ceramic shell investment mould. The addition of calcium carbonate to pure cement in the form of naked test bars, produced a more unified formula that did not break into separate pieces when fired to 9450C. However this combination of cement and calcium carbonate had a slow setting time of 12 hours and a shrinkage value of 2,3%, which were both above the parameters being sought for a quick-setting formula with a shrinkage value of below 1%. The combination of cement, plaster of paris and silica produced formulae that set within six hours and had shrinkage values of less than 1% but did not disintegrate within 72 hours. It was only after the addition of calcium carbonate to the these mixes that formulae resulted that set within six hours, had relatively low shrinkage values and showed signs of breaking up after 60 hours. It was further shown that by altering the ratios of cement, plaster of paris, calcium carbonate and silica, that the parameters for quick-setting formulae with shrinkage values of 1% and below, that also disintegrated within 55 hours, could be achieved. xvi It was also proved by subjecting these formulae to higher relative humidity conditions that the disintegrating times could be reduced and brought to below 48 hours. Selected formulae were then subjected to temperatures of between 9000C and 10000C. It was found that as the temperatures were increased so the disintegration times were reduced and were even further reduced under higher relative humidity conditions. It was found from the above experiments that the selected formula determined to be suitable in all respects as a disintegrating core-body was too difficult to remove from the hollow bronze cast when subjected to an actual bronze pour. Further experimentation using increased proportions of silica in the formula resulted in a final core-body that could be quickly and easily removed from its bronze cast as soon as the core-body had cooled to room temperature. The selected core-body formula (F21D) that was used in the final set of bronze casting procedures was found to function optimally when fired to a temperature of 9000C and could be quickly and easily removed from the bronze casts leaving a clean inner bronze surface, free from any remnants of the fired core. The document concludes by recording the delimitations and advantages of the final core-body formula F21D, as well as making recommendations based on these parameters for further study relating to disintegrating core-body formulations.
- Full Text:
- Date Issued: 2004
- Authors: Lomax, Lawrence Talbot
- Date: 2004
- Subjects: Sculpture -- Technique , Bronze founding , Precision casting , Shell molding (Founding)
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:8499 , http://hdl.handle.net/10948/219 , Sculpture -- Technique , Bronze founding , Precision casting , Shell molding (Founding)
- Description: The development of a disintegrating core-body for use in an art bronze foundry, which employs the ceramic shell investment process, begins with an investigation of four principal materials that will constitute the core formula. The specifications for the disintegration of the designed core-body formula fall within the parameters that are normally set and used in the ceramic shell art bronze casting process. The raison d’ être for the disintegrating formula is based on the premise that cement breaks down (spalling) after being subjected to heat above a certain temperature. It was shown that pure cement in the form of naked test bars 100 mm x 20 mm x 20 mm does indeed break down into separate pieces when fired to and above 9000C; where 9000C is the lowest recommended temperature required for sintering the ceramic shell investment mould. The addition of calcium carbonate to pure cement in the form of naked test bars, produced a more unified formula that did not break into separate pieces when fired to 9450C. However this combination of cement and calcium carbonate had a slow setting time of 12 hours and a shrinkage value of 2,3%, which were both above the parameters being sought for a quick-setting formula with a shrinkage value of below 1%. The combination of cement, plaster of paris and silica produced formulae that set within six hours and had shrinkage values of less than 1% but did not disintegrate within 72 hours. It was only after the addition of calcium carbonate to the these mixes that formulae resulted that set within six hours, had relatively low shrinkage values and showed signs of breaking up after 60 hours. It was further shown that by altering the ratios of cement, plaster of paris, calcium carbonate and silica, that the parameters for quick-setting formulae with shrinkage values of 1% and below, that also disintegrated within 55 hours, could be achieved. xvi It was also proved by subjecting these formulae to higher relative humidity conditions that the disintegrating times could be reduced and brought to below 48 hours. Selected formulae were then subjected to temperatures of between 9000C and 10000C. It was found that as the temperatures were increased so the disintegration times were reduced and were even further reduced under higher relative humidity conditions. It was found from the above experiments that the selected formula determined to be suitable in all respects as a disintegrating core-body was too difficult to remove from the hollow bronze cast when subjected to an actual bronze pour. Further experimentation using increased proportions of silica in the formula resulted in a final core-body that could be quickly and easily removed from its bronze cast as soon as the core-body had cooled to room temperature. The selected core-body formula (F21D) that was used in the final set of bronze casting procedures was found to function optimally when fired to a temperature of 9000C and could be quickly and easily removed from the bronze casts leaving a clean inner bronze surface, free from any remnants of the fired core. The document concludes by recording the delimitations and advantages of the final core-body formula F21D, as well as making recommendations based on these parameters for further study relating to disintegrating core-body formulations.
- Full Text:
- Date Issued: 2004
The oxidative coupling of phenols using stoichiometric metal oxidants
- Authors: Hoffmann, Eric
- Date: 2005
- Subjects: Phenols , Oxidation , Stoichiometry
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:10977 , http://hdl.handle.net/10948/180 , Phenols , Oxidation , Stoichiometry
- Description: The oxidative coupling of 2,6-di-t-butylphenol under mild reaction conditions is well documented and the subject of many patents. However, the coupling of other monoand di- substituted phenols is not as well documented and thus there is scope for further investigation for providing a convenient, environmentally friendly and economically viable method for the oxidative coupling of these phenols. In this study, the oxidative coupling of a variety of alkylated phenolic substrates, 2-tbutylphenol, 2,6-di-t-butylphenol, 2,4 -di-t-butylphenol and ,4-dimethylphenol, using a range of different oxidizing agents, were investigated by means of experimental and/or theoretical means. The dibutylated aromatics provided the highest selectivities to their respective coupled products, with results obtained with the dimethyl analogue being only satisfactory, and that for 2 -t-butylphenol being totally inefficient. PM3 Molecular orbital (MO) calculations were used to predict the possible modes of coupling for the substrates 2,6 -di-t-butylphenol and 2,4-di-t-butylphenol, and these results were then compared with those obtained experimentally in the laboratory. Preliminarily, the coupling of unsubstituted phenolics was also assessed by means of MO calculations. Much emphasis was placed on Ce(IV) as the oxidant, and the reaction conditions under which it was used and the results that were obtained have not been reported before and are therefore novel. The oxidation of 2,4-di-t-butylphenol using Ce(IV) in the presence of methanesulphonic acid was optimized to afford high yields and selectivities to the desired ortho C-ortho C coupled product under mild reaction conditions. Various reaction parameters were also investigated in this case, such as varying the MeSO3H concentration, the solvent, the reaction temperature, the reaction time, the substrate loading, the rate of oxidant addition and the substrate to oxidant ratio. Ce(IV) also gave a high selectivity to the para C-para C coupled product when IX using 2,6-di-t-butylphenol as the substrate. However, it was not as effective with 2,4- dimethylphenol, and even less so with 2-t-butylphenol. The oxidation reactions of 2-t-butylphenol and 2,4-dimethylphenol with various coupling agents were also investigated with the intention of obtaining high selectivities to the respective desired coupled products. In these studies, 2-t-butylphenol afforded a large number of products, irrespective of the oxidant used. The dimethyl analogue was more selective, but results were not optimal. It was clear that the number of substituents on the phenol ring, their nature and their position with regards to the hydroxyl moiety was of great importance and made a significant impact on the preferred coupling mode of the substrate. It was observed that steric effects also played a major role in the outcome of these reactions: 2,6-di-t-butylphenol never afforded any C-O coupled products whereas 2-t-butylphenol, 2,4-di-t-butylphenol and 2,4-dimethylphenol all appeared to undergo some C-O coupling. Finally, reaction mechanisms were provided for both the K3Fe(CN)6 and Ce(IV) work, these reacting in basic and acidic media, respectively. It was proposed that both of these mechanisms operate through the initial formation of the phenoxyl radical.
- Full Text:
- Date Issued: 2005
- Authors: Hoffmann, Eric
- Date: 2005
- Subjects: Phenols , Oxidation , Stoichiometry
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:10977 , http://hdl.handle.net/10948/180 , Phenols , Oxidation , Stoichiometry
- Description: The oxidative coupling of 2,6-di-t-butylphenol under mild reaction conditions is well documented and the subject of many patents. However, the coupling of other monoand di- substituted phenols is not as well documented and thus there is scope for further investigation for providing a convenient, environmentally friendly and economically viable method for the oxidative coupling of these phenols. In this study, the oxidative coupling of a variety of alkylated phenolic substrates, 2-tbutylphenol, 2,6-di-t-butylphenol, 2,4 -di-t-butylphenol and ,4-dimethylphenol, using a range of different oxidizing agents, were investigated by means of experimental and/or theoretical means. The dibutylated aromatics provided the highest selectivities to their respective coupled products, with results obtained with the dimethyl analogue being only satisfactory, and that for 2 -t-butylphenol being totally inefficient. PM3 Molecular orbital (MO) calculations were used to predict the possible modes of coupling for the substrates 2,6 -di-t-butylphenol and 2,4-di-t-butylphenol, and these results were then compared with those obtained experimentally in the laboratory. Preliminarily, the coupling of unsubstituted phenolics was also assessed by means of MO calculations. Much emphasis was placed on Ce(IV) as the oxidant, and the reaction conditions under which it was used and the results that were obtained have not been reported before and are therefore novel. The oxidation of 2,4-di-t-butylphenol using Ce(IV) in the presence of methanesulphonic acid was optimized to afford high yields and selectivities to the desired ortho C-ortho C coupled product under mild reaction conditions. Various reaction parameters were also investigated in this case, such as varying the MeSO3H concentration, the solvent, the reaction temperature, the reaction time, the substrate loading, the rate of oxidant addition and the substrate to oxidant ratio. Ce(IV) also gave a high selectivity to the para C-para C coupled product when IX using 2,6-di-t-butylphenol as the substrate. However, it was not as effective with 2,4- dimethylphenol, and even less so with 2-t-butylphenol. The oxidation reactions of 2-t-butylphenol and 2,4-dimethylphenol with various coupling agents were also investigated with the intention of obtaining high selectivities to the respective desired coupled products. In these studies, 2-t-butylphenol afforded a large number of products, irrespective of the oxidant used. The dimethyl analogue was more selective, but results were not optimal. It was clear that the number of substituents on the phenol ring, their nature and their position with regards to the hydroxyl moiety was of great importance and made a significant impact on the preferred coupling mode of the substrate. It was observed that steric effects also played a major role in the outcome of these reactions: 2,6-di-t-butylphenol never afforded any C-O coupled products whereas 2-t-butylphenol, 2,4-di-t-butylphenol and 2,4-dimethylphenol all appeared to undergo some C-O coupling. Finally, reaction mechanisms were provided for both the K3Fe(CN)6 and Ce(IV) work, these reacting in basic and acidic media, respectively. It was proposed that both of these mechanisms operate through the initial formation of the phenoxyl radical.
- Full Text:
- Date Issued: 2005
Factors influencing survivor qualities after downsizing
- Authors: Chipunza, Crispen
- Date: 2009
- Subjects: Downsizing of organizations -- South Africa , Organizational change -- South Africa , Cost control , Unemployment -- Psychological aspects
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:9381 , http://hdl.handle.net/10948/1219 , Downsizing of organizations -- South Africa , Organizational change -- South Africa , Cost control , Unemployment -- Psychological aspects
- Description: Today organisations all over the world have to cope with the ever-increasing rate of local and global change. Those in developing countries have to cope with the inefficiencies engendered by state-led economic, developmental and political strategies, such as new government regulations. These have had an impact on the management of human resources and are exemplified by an increasing adoption of strategies meant to reduce pressure on costs and margins. An increasing popular management response to these challenges has been to engage in some form of organisational restructuring such as downsizing. Often employees who remain (survivors) after downsizing are not given much attention, yet the achievement of new strategic goals depends on the survivors having positive attitudes, relentless commitment and high motivation. Research indicates that employees who are motivated and committed contribute vastly to the financial-bottom-line of the organisation. Therefore, downsizing organisations should continuously search for ways to increase such qualities among their survivors. The objective of this study was to identify the factors that influence the attitudes, commitment and motivation of survivors in a developing economy with a volatile environment. To achieve this objective, a theoretical survivor quality model was presented. In order to present the model, firstly, a literature survey on the importance of survivor quality in terms of attitudes, commitment, and motivation among survivors was conducted. Secondly, literature survey pertaining to the drivers of survivor quality was done, and thirdly, literature dealing with strategies to deal with survivor quality was surveyed. The theoretical survivor quality model was used to compile the research instrument that determined the attitudinal, commitment and motivational levels of survivors, how the three constructs are related after downsizing, as well as the factors influencing the observed levels. The questionnaire was randomly distributed among survivors in the selected manufacturing organisations in Zimbabwe. The empirical results obtained from the study showed that survivors in a developing economy with a volatile environment had moderate levels of attitudes, commitment ad motivation. Two categories of factors were identified as important in influencing these levels. They were downsizing strategy and demographic factors. The downsizing strategy factors were communication and victim support, while education, age, and number of years employed emerged as the demographic factors. The study further highlighted that older survivors with less education contributed more to the moderate levels of attitude, commitment and motivation observed. The study highlights that these variables must be taken into consideration when implementing downsizing in an economically volatile environment in order to manage survivor quality. A further point emanating from the study is that prior to downsizing, organisations should adopt effective communication strategies throughout the process. The key factors identified as influencing survivor quality in this study were integrated into the survivor quality model which can be used by other organisations in a similar context to manage survivor quality in order to increase their efficiency, effectiveness, iv and competitive advantage after downsizing.
- Full Text:
- Date Issued: 2009
- Authors: Chipunza, Crispen
- Date: 2009
- Subjects: Downsizing of organizations -- South Africa , Organizational change -- South Africa , Cost control , Unemployment -- Psychological aspects
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:9381 , http://hdl.handle.net/10948/1219 , Downsizing of organizations -- South Africa , Organizational change -- South Africa , Cost control , Unemployment -- Psychological aspects
- Description: Today organisations all over the world have to cope with the ever-increasing rate of local and global change. Those in developing countries have to cope with the inefficiencies engendered by state-led economic, developmental and political strategies, such as new government regulations. These have had an impact on the management of human resources and are exemplified by an increasing adoption of strategies meant to reduce pressure on costs and margins. An increasing popular management response to these challenges has been to engage in some form of organisational restructuring such as downsizing. Often employees who remain (survivors) after downsizing are not given much attention, yet the achievement of new strategic goals depends on the survivors having positive attitudes, relentless commitment and high motivation. Research indicates that employees who are motivated and committed contribute vastly to the financial-bottom-line of the organisation. Therefore, downsizing organisations should continuously search for ways to increase such qualities among their survivors. The objective of this study was to identify the factors that influence the attitudes, commitment and motivation of survivors in a developing economy with a volatile environment. To achieve this objective, a theoretical survivor quality model was presented. In order to present the model, firstly, a literature survey on the importance of survivor quality in terms of attitudes, commitment, and motivation among survivors was conducted. Secondly, literature survey pertaining to the drivers of survivor quality was done, and thirdly, literature dealing with strategies to deal with survivor quality was surveyed. The theoretical survivor quality model was used to compile the research instrument that determined the attitudinal, commitment and motivational levels of survivors, how the three constructs are related after downsizing, as well as the factors influencing the observed levels. The questionnaire was randomly distributed among survivors in the selected manufacturing organisations in Zimbabwe. The empirical results obtained from the study showed that survivors in a developing economy with a volatile environment had moderate levels of attitudes, commitment ad motivation. Two categories of factors were identified as important in influencing these levels. They were downsizing strategy and demographic factors. The downsizing strategy factors were communication and victim support, while education, age, and number of years employed emerged as the demographic factors. The study further highlighted that older survivors with less education contributed more to the moderate levels of attitude, commitment and motivation observed. The study highlights that these variables must be taken into consideration when implementing downsizing in an economically volatile environment in order to manage survivor quality. A further point emanating from the study is that prior to downsizing, organisations should adopt effective communication strategies throughout the process. The key factors identified as influencing survivor quality in this study were integrated into the survivor quality model which can be used by other organisations in a similar context to manage survivor quality in order to increase their efficiency, effectiveness, iv and competitive advantage after downsizing.
- Full Text:
- Date Issued: 2009