A critical analysis of selected literary techniques in P.T. Mtuze’s prose narratives
- Authors: Kondowe, Zandile Ziyanda
- Date: 2016
- Subjects: Xhosa literature -- History and criticism Literary style
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/33217 , vital:32570
- Description: The main purpose of this study is to provide a critical analysis of selected literary techniques in P.T. Mtuze’s prose narratives. This study seeks to analyse his style of writing in all his texts. The aspects of his style under stylistic techniques and criticism will serve as a foundation theory that will link the study to the analysis of definitions and referencing under imagery and its aspects; including humour, satire, idioms, proverbs, literary techniques, and figures of speech. Mtuze is noted as one of the most prolific writers due to his ingenuity in language skills, especially in isiXhosa. Mtuze is one of the best humoristic writers; hence he is popular due to applying humour in the prose works he wrote. This study is divided into seven chapters, and the theory which is used for this study is also scrutinised in order to get a sense of what the author intended to deliver through his texts.
- Full Text:
- Date Issued: 2016
- Authors: Kondowe, Zandile Ziyanda
- Date: 2016
- Subjects: Xhosa literature -- History and criticism Literary style
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/33217 , vital:32570
- Description: The main purpose of this study is to provide a critical analysis of selected literary techniques in P.T. Mtuze’s prose narratives. This study seeks to analyse his style of writing in all his texts. The aspects of his style under stylistic techniques and criticism will serve as a foundation theory that will link the study to the analysis of definitions and referencing under imagery and its aspects; including humour, satire, idioms, proverbs, literary techniques, and figures of speech. Mtuze is noted as one of the most prolific writers due to his ingenuity in language skills, especially in isiXhosa. Mtuze is one of the best humoristic writers; hence he is popular due to applying humour in the prose works he wrote. This study is divided into seven chapters, and the theory which is used for this study is also scrutinised in order to get a sense of what the author intended to deliver through his texts.
- Full Text:
- Date Issued: 2016
A framework for enhancing trust for improved participation in electronic marketplaces accessed from mobile platforms
- Isabirye, Naomi Nabirye, Von Solms, R
- Authors: Isabirye, Naomi Nabirye , Von Solms, R
- Date: 2016
- Subjects: Information technology -- Economic aspects -- South Africa Agricultural innovations -- South Africa Agricultural systems -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/20019 , vital:29053
- Description: Information and communication technologies (ICTs) have been widely researched as a mechanism for improving the socio-economic status of disadvantaged, rural communities. In order to do this numerous technology-based initiatives have been introduced into disadvantaged, rural communities to assist them in various aspects of their lives. Unfortunately, even when the proposed benefit of a particular technology is clearly evident to its initiators, the adoption by the target users is often uncertain. This has also been the case with e-commerce in agriculture. Despite the numerous benefits of e-commerce for agricultural producers, the uptake has been low. Trust is a critical pre-condition for the adoption of e-marketplaces. E-marketplaces expose consumers to the risk of non-delivery or misrepresentation of goods ordered and the misuse of personal information by external parties. Additionally, the time investment needed to make a shift to e-marketplaces and the opinions of important reference groups affects the user’s willingness to trust and depend on an e-marketplace. This study was undertaken to assess the extent to which rural users with limited ICT experience would trust and, consequently, adopt an e-marketplace to support agricultural trade. A pragmatic philosophy was adopted in this study, indicating that the researcher’s view of reality is founded on the practical implications and outcomes that are observed. This study used a Canonical Action Research strategy to design, develop and deploy a voice based e-marketplace to assist the trading activities of a Western Cape based aloe community. The community was allowed to utilise thee-marketplace over a period of eight weeks. Thereafter, interviews were held with the participants to investigate their perceptions of the technology. As a result, a model proposing the factors that must be in place for trust to be achieved in a voice based e-marketplace was proposed. The study found that the trustworthiness of a technology results from the technology’s technical capability to satisfy the needs of its users reliably. Usability and security were found to be important determinants of the trustworthiness of a technology. Furthermore, the requirements elicitation process was found to be central to achieving trust as it defines the necessary criteria for developing secure, usable, functional, and reliable technologies that meet the needs of their users.
- Full Text:
- Date Issued: 2016
- Authors: Isabirye, Naomi Nabirye , Von Solms, R
- Date: 2016
- Subjects: Information technology -- Economic aspects -- South Africa Agricultural innovations -- South Africa Agricultural systems -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/20019 , vital:29053
- Description: Information and communication technologies (ICTs) have been widely researched as a mechanism for improving the socio-economic status of disadvantaged, rural communities. In order to do this numerous technology-based initiatives have been introduced into disadvantaged, rural communities to assist them in various aspects of their lives. Unfortunately, even when the proposed benefit of a particular technology is clearly evident to its initiators, the adoption by the target users is often uncertain. This has also been the case with e-commerce in agriculture. Despite the numerous benefits of e-commerce for agricultural producers, the uptake has been low. Trust is a critical pre-condition for the adoption of e-marketplaces. E-marketplaces expose consumers to the risk of non-delivery or misrepresentation of goods ordered and the misuse of personal information by external parties. Additionally, the time investment needed to make a shift to e-marketplaces and the opinions of important reference groups affects the user’s willingness to trust and depend on an e-marketplace. This study was undertaken to assess the extent to which rural users with limited ICT experience would trust and, consequently, adopt an e-marketplace to support agricultural trade. A pragmatic philosophy was adopted in this study, indicating that the researcher’s view of reality is founded on the practical implications and outcomes that are observed. This study used a Canonical Action Research strategy to design, develop and deploy a voice based e-marketplace to assist the trading activities of a Western Cape based aloe community. The community was allowed to utilise thee-marketplace over a period of eight weeks. Thereafter, interviews were held with the participants to investigate their perceptions of the technology. As a result, a model proposing the factors that must be in place for trust to be achieved in a voice based e-marketplace was proposed. The study found that the trustworthiness of a technology results from the technology’s technical capability to satisfy the needs of its users reliably. Usability and security were found to be important determinants of the trustworthiness of a technology. Furthermore, the requirements elicitation process was found to be central to achieving trust as it defines the necessary criteria for developing secure, usable, functional, and reliable technologies that meet the needs of their users.
- Full Text:
- Date Issued: 2016
A framework for grain commodity trading decision support in South Africa
- Authors: Ayankoya, Kayode Anthony
- Date: 2016
- Subjects: Grain trade -- South Africa Commodity exchanges -- South Africa Food industry and trade -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/11437 , vital:26925
- Description: In several countries around the world, grain commodities are traded as assets on stock exchanges. This indicate that the market and effectively the prices of the grain commodities in such countries, are controlled by several local and international economic, political and social factors that are rapidly changing. As a result, the prices of some grain commodities are volatile and trading in such commodities are prone to price-related risks. There are different trading strategies for minimising price-related risks and maximising profits. But empirical research suggests that making the right decision for effective grain commodities trading has been a difficult task for stakeholders due to high volatility of grain commodities prices. Studies have shown that this is more challenging among grain commodities farmers because of their lack of skills and the time to sift through and make sense of the datasets on the plethora of factors that influence the grain commodities market. This thesis focused on providing an answer for the main research problem that grain farmers in South Africa do not take full advantage of all the available strategies for trading their grain commodities because of the complexities associated with monitoring the large datasets that influence the grain commodities market. The main objective set by this study is to design a framework that can be followed to collect, integrate and analyse datasets that influence trading decisions of grain farmers in South Africa about grain commodities. This study takes advantage of the developments in Big Data and Data Science to achieve the set objective using the Design Science Research (DSR) methodology. The prediction of future prices of grain commodities for the different trading strategies was identified as an important factor for making better decisions when trading grain commodities and the key factors that influence the prices were identified. This was followed by a critical review of the literature to determine how the concepts of Big Data and Data Science can be leveraged for an effective grain commodities trading decision support. This resulted in a proposed framework for grain commodities trading. The proposed framework suggested an investigation of the factors that influence the prices of grain commodities as the basis for acquiring the relevant datasets. The proposed framework suggested the adoption of the Big Data approach in acquiring, preparing and integrating relevant datasets from several sources. Furthermore, it was suggested that algorithmic models for predicting grain commodities prices can be developed on top of the data layer of the proposed framework to provide real-time decision support. The proposed framework suggests the need for a carefully designed visualisation of the result and the collected data that promotes user experience. Lastly, the proposed framework included a technology consideration component to support the Big Data and Data Science approach of the framework. To demonstrate that the proposed framework addressed the main problem of this research, datasets from several sources on trading white maize in South Africa and the factors that influence market were streamed, integrated and analysed. Backpropagation Neural Network algorithm was used for modelling the prices of white maize for spot and futures trading strategies were predicted. There are other modelling techniques such as the Box-Jenkins statistical time series analysis methodology. But, Neural Networks was identified as more suitable for time series data with complex patterns and relationships. A demonstration system was setup to provide effective decision support by using near real-time data to provide a dynamic predictive analytics for the spot and December futures contract prices of white maize in South Africa. Comparative analysis of predictions made using the model from the proposed framework to actual data indicated a significant degree of accuracy. A further evaluation was carried out by asking experienced traders to make predictions for the spot and December futures contract prices of white maize. The result of the exercise indicated that the predictions from the developed model were much closer to the actual prices. This indicated that the proposed framework is technically capable and generally useful. It also shows that the proposed framework can be used to provide decision support about trading grain commodities to stakeholders with lesser skills, experience and resources. The practical contribution of this thesis is that relevant datasets from several sources can be streamed into an integrated data source in real-time, which can be used as input for a real-time learning algorithmic model for predicting grain commodities prices. This will make it possible for a predictive analytics that responds to market volatility thereby providing an effective decision support for grain commodities trading. Another practical contribution of this thesis is a proposed framework that can be followed for developing a Decision Support System for trading in grain commodities. This thesis made theoretical contributions by building on the information processing theory and the decision making theory. The theoretical contribution of this thesis consists of the identification of Big Data approach, tools and techniques for eradicating uncertainty and equivocality in grain commodities trading decision making process.
- Full Text:
- Date Issued: 2016
- Authors: Ayankoya, Kayode Anthony
- Date: 2016
- Subjects: Grain trade -- South Africa Commodity exchanges -- South Africa Food industry and trade -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/11437 , vital:26925
- Description: In several countries around the world, grain commodities are traded as assets on stock exchanges. This indicate that the market and effectively the prices of the grain commodities in such countries, are controlled by several local and international economic, political and social factors that are rapidly changing. As a result, the prices of some grain commodities are volatile and trading in such commodities are prone to price-related risks. There are different trading strategies for minimising price-related risks and maximising profits. But empirical research suggests that making the right decision for effective grain commodities trading has been a difficult task for stakeholders due to high volatility of grain commodities prices. Studies have shown that this is more challenging among grain commodities farmers because of their lack of skills and the time to sift through and make sense of the datasets on the plethora of factors that influence the grain commodities market. This thesis focused on providing an answer for the main research problem that grain farmers in South Africa do not take full advantage of all the available strategies for trading their grain commodities because of the complexities associated with monitoring the large datasets that influence the grain commodities market. The main objective set by this study is to design a framework that can be followed to collect, integrate and analyse datasets that influence trading decisions of grain farmers in South Africa about grain commodities. This study takes advantage of the developments in Big Data and Data Science to achieve the set objective using the Design Science Research (DSR) methodology. The prediction of future prices of grain commodities for the different trading strategies was identified as an important factor for making better decisions when trading grain commodities and the key factors that influence the prices were identified. This was followed by a critical review of the literature to determine how the concepts of Big Data and Data Science can be leveraged for an effective grain commodities trading decision support. This resulted in a proposed framework for grain commodities trading. The proposed framework suggested an investigation of the factors that influence the prices of grain commodities as the basis for acquiring the relevant datasets. The proposed framework suggested the adoption of the Big Data approach in acquiring, preparing and integrating relevant datasets from several sources. Furthermore, it was suggested that algorithmic models for predicting grain commodities prices can be developed on top of the data layer of the proposed framework to provide real-time decision support. The proposed framework suggests the need for a carefully designed visualisation of the result and the collected data that promotes user experience. Lastly, the proposed framework included a technology consideration component to support the Big Data and Data Science approach of the framework. To demonstrate that the proposed framework addressed the main problem of this research, datasets from several sources on trading white maize in South Africa and the factors that influence market were streamed, integrated and analysed. Backpropagation Neural Network algorithm was used for modelling the prices of white maize for spot and futures trading strategies were predicted. There are other modelling techniques such as the Box-Jenkins statistical time series analysis methodology. But, Neural Networks was identified as more suitable for time series data with complex patterns and relationships. A demonstration system was setup to provide effective decision support by using near real-time data to provide a dynamic predictive analytics for the spot and December futures contract prices of white maize in South Africa. Comparative analysis of predictions made using the model from the proposed framework to actual data indicated a significant degree of accuracy. A further evaluation was carried out by asking experienced traders to make predictions for the spot and December futures contract prices of white maize. The result of the exercise indicated that the predictions from the developed model were much closer to the actual prices. This indicated that the proposed framework is technically capable and generally useful. It also shows that the proposed framework can be used to provide decision support about trading grain commodities to stakeholders with lesser skills, experience and resources. The practical contribution of this thesis is that relevant datasets from several sources can be streamed into an integrated data source in real-time, which can be used as input for a real-time learning algorithmic model for predicting grain commodities prices. This will make it possible for a predictive analytics that responds to market volatility thereby providing an effective decision support for grain commodities trading. Another practical contribution of this thesis is a proposed framework that can be followed for developing a Decision Support System for trading in grain commodities. This thesis made theoretical contributions by building on the information processing theory and the decision making theory. The theoretical contribution of this thesis consists of the identification of Big Data approach, tools and techniques for eradicating uncertainty and equivocality in grain commodities trading decision making process.
- Full Text:
- Date Issued: 2016
A framework for the inclusion of students with visual impairments: a case of a Zimbabwe state university
- Authors: Manyumwa, Ennie
- Date: 2016
- Subjects: Inclusive education -- Zimbabwe Students with disabilities -- Education (Higher) -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/29805 , vital:30780
- Description: The aim of this study was to explore the experiences of students with visual impairments in a selected state university in Zimbabwe in order to develop a framework for their inclusion. The study was necessitated by the increased enrolment of students with visual impairments in universities worldwide in response to inclusion in education and the continuous search for the best placement model for students with disabilities. Studies conducted internationally show that students with visual impairments have unique learning needs which must be addressed if their inclusion in universities is to be successful. The study was informed by Bronfenbrenner’s ecological and Bandura’s agentic theories, both of which stress the bi-directional relationship between an individual and the environment. The transformative paradigm which guided this study, lays emphasis on the need to improve the social situation of individuals with disabilities in order to bring about a more equitable society. Since the study intended to gain an understanding of how students with visual impairments interpret their experiences within a selected state university in Zimbabwe which practices inclusion, the qualitative case study design was used. Purposeful sampling was also used in the selection of both the university studied and the participants. Data generation methods employed included the semi-structured interview, photo-voice, document analysis and observation. Data generated were analysed following emergent themes that were used to answer the research questions. Findings revealed that the university started enrolling students with visual impairments in 2004 and has since established a Disability Resource Centre which is equipped with assistive devices and is manned by caring staff. Findings revealed a glaring absence of a university policy on inclusion. The guiding principles used did not clearly articulate issues of inclusion. The students’ positive experiences resulted from single rooms allocated to them and the support received from friends and caring staff. Negative experiences emanated from bureaucratic admission procedures, challenges of adjusting to university life in the absence of orientation and mobility training, financial challenges, hostile social environment and the students’ perceptions of themselves. The students suggested that the university should assist them with fees and expressed their wish to be consulted on matters that concern them. They xviii also suggested close co-operation between the administration and the Disability Resource Centre. The conclusion reached was that although the university was sensitive to issues of inclusion, there were still some deficiencies in the system that were impacting negatively on the inclusion of students with visual impairments. The study recommended a framework which shows the different committees and support systems which can be formed at different levels to facilitate the development of a comprehensive policy on inclusion and expedite its implementation. The involvement of students with visual impairments in the different committees was also recommended. This would afford them the chance to exercise their agentic resources and be involved in matters which concern them, rather than rely on decisions made by sighted individuals who might not possess adequate knowledge of what visual impairment entails.
- Full Text:
- Date Issued: 2016
- Authors: Manyumwa, Ennie
- Date: 2016
- Subjects: Inclusive education -- Zimbabwe Students with disabilities -- Education (Higher) -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/29805 , vital:30780
- Description: The aim of this study was to explore the experiences of students with visual impairments in a selected state university in Zimbabwe in order to develop a framework for their inclusion. The study was necessitated by the increased enrolment of students with visual impairments in universities worldwide in response to inclusion in education and the continuous search for the best placement model for students with disabilities. Studies conducted internationally show that students with visual impairments have unique learning needs which must be addressed if their inclusion in universities is to be successful. The study was informed by Bronfenbrenner’s ecological and Bandura’s agentic theories, both of which stress the bi-directional relationship between an individual and the environment. The transformative paradigm which guided this study, lays emphasis on the need to improve the social situation of individuals with disabilities in order to bring about a more equitable society. Since the study intended to gain an understanding of how students with visual impairments interpret their experiences within a selected state university in Zimbabwe which practices inclusion, the qualitative case study design was used. Purposeful sampling was also used in the selection of both the university studied and the participants. Data generation methods employed included the semi-structured interview, photo-voice, document analysis and observation. Data generated were analysed following emergent themes that were used to answer the research questions. Findings revealed that the university started enrolling students with visual impairments in 2004 and has since established a Disability Resource Centre which is equipped with assistive devices and is manned by caring staff. Findings revealed a glaring absence of a university policy on inclusion. The guiding principles used did not clearly articulate issues of inclusion. The students’ positive experiences resulted from single rooms allocated to them and the support received from friends and caring staff. Negative experiences emanated from bureaucratic admission procedures, challenges of adjusting to university life in the absence of orientation and mobility training, financial challenges, hostile social environment and the students’ perceptions of themselves. The students suggested that the university should assist them with fees and expressed their wish to be consulted on matters that concern them. They xviii also suggested close co-operation between the administration and the Disability Resource Centre. The conclusion reached was that although the university was sensitive to issues of inclusion, there were still some deficiencies in the system that were impacting negatively on the inclusion of students with visual impairments. The study recommended a framework which shows the different committees and support systems which can be formed at different levels to facilitate the development of a comprehensive policy on inclusion and expedite its implementation. The involvement of students with visual impairments in the different committees was also recommended. This would afford them the chance to exercise their agentic resources and be involved in matters which concern them, rather than rely on decisions made by sighted individuals who might not possess adequate knowledge of what visual impairment entails.
- Full Text:
- Date Issued: 2016
A framework to evaluate user experience of end user application security features
- Authors: Shava, Fungai Bhunu
- Date: 2016
- Subjects: User interfaces (Computer systems) -- Design Web sites -- Design
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/12951 , vital:27137
- Description: The use of technology in society moved from satisfying the technical needs of users to giving a lasting user experience while interacting with the technology. The continuous technological advancements have led to a diversity of emerging security concerns. It is necessary to balance security issues with user interaction. As such, designers have adapted to this reality by practising user centred design during product development to cater for the experiential needs of user - product interaction. These User Centred Design best practices and standards ensure that security features are incorporated within End User Programs (EUP). The primary function of EUP is not security, and interaction with security features while performing a program related task does present the end user with an extra burden. Evaluation mechanisms exist to enumerate the performance of the EUP and the user’s experience of the product interaction. Security evaluation standards focus on the program code security as well as on security functionalities of programs designed for security. However, little attention has been paid to evaluating user experience of functionalities offered by embedded security features. A qualitative case study research using problem based and design science research approaches was used to address the lack of criteria to evaluate user experience with embedded security features. User study findings reflect poor user experience with EUP security features, mainly as a result of low awareness of their existence, their location and sometimes even of their importance. From the literature review of the information security and user experience domains and the user study survey findings, four components of the framework were identified, namely: end user characteristics, information security, user experience and end user program security features characteristics. This thesis focuses on developing a framework that can be used to evaluate the user experience of interacting with end user program security features. The framework was designed following the design science research method and was reviewed by peers and experts for its suitability to address the problem. Subject experts in the fields of information security and human computer interaction were engaged, as the research is multidisciplinary. This thesis contributes to the body of knowledge on information security and on user experience elements of human computer interaction security regarding how to evaluate user experience of embedded InfoSec features. The research adds uniquely to the literature in the area of Human Computer Interaction Security evaluation and measurement in general, and is specific to end user program security features. The proposed metrics for evaluating UX of interacting with EUP security features were used to propose intervention to influence UX in an academic setup. The framework, besides presenting UX evaluation strategies for EUP security features, also presents a platform for further academic research on human factors of information security. The impact can be evaluated by assessing security behaviour, and successful security breaches, as well as user experience of interaction with end user programs.
- Full Text:
- Date Issued: 2016
- Authors: Shava, Fungai Bhunu
- Date: 2016
- Subjects: User interfaces (Computer systems) -- Design Web sites -- Design
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/12951 , vital:27137
- Description: The use of technology in society moved from satisfying the technical needs of users to giving a lasting user experience while interacting with the technology. The continuous technological advancements have led to a diversity of emerging security concerns. It is necessary to balance security issues with user interaction. As such, designers have adapted to this reality by practising user centred design during product development to cater for the experiential needs of user - product interaction. These User Centred Design best practices and standards ensure that security features are incorporated within End User Programs (EUP). The primary function of EUP is not security, and interaction with security features while performing a program related task does present the end user with an extra burden. Evaluation mechanisms exist to enumerate the performance of the EUP and the user’s experience of the product interaction. Security evaluation standards focus on the program code security as well as on security functionalities of programs designed for security. However, little attention has been paid to evaluating user experience of functionalities offered by embedded security features. A qualitative case study research using problem based and design science research approaches was used to address the lack of criteria to evaluate user experience with embedded security features. User study findings reflect poor user experience with EUP security features, mainly as a result of low awareness of their existence, their location and sometimes even of their importance. From the literature review of the information security and user experience domains and the user study survey findings, four components of the framework were identified, namely: end user characteristics, information security, user experience and end user program security features characteristics. This thesis focuses on developing a framework that can be used to evaluate the user experience of interacting with end user program security features. The framework was designed following the design science research method and was reviewed by peers and experts for its suitability to address the problem. Subject experts in the fields of information security and human computer interaction were engaged, as the research is multidisciplinary. This thesis contributes to the body of knowledge on information security and on user experience elements of human computer interaction security regarding how to evaluate user experience of embedded InfoSec features. The research adds uniquely to the literature in the area of Human Computer Interaction Security evaluation and measurement in general, and is specific to end user program security features. The proposed metrics for evaluating UX of interacting with EUP security features were used to propose intervention to influence UX in an academic setup. The framework, besides presenting UX evaluation strategies for EUP security features, also presents a platform for further academic research on human factors of information security. The impact can be evaluated by assessing security behaviour, and successful security breaches, as well as user experience of interaction with end user programs.
- Full Text:
- Date Issued: 2016
A maturity grid-based method for assessing communication in business-IT alignment
- Authors: Coertze, Jacques Jacobus
- Date: 2016
- Subjects: Business communication , Management information systems
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/6740 , vital:21139
- Description: This thesis reports on the research undertaken to develop a method for organisations to assess human communication between their business and IT personnel as part of business–IT alignment. The research described in this thesis involves (i) a literature review in business–IT alignment and related fields, such as management studies and communication science; (ii) a Delphi study conducted among industry members, practitioners, and academics operating in the IT advisory, auditing and communication disciplines; and (iii) a case study of a public sector organisation in South Africa. By adopting a system-theoretic perspective on communication, this thesis proposes that communication in business–IT alignment can be seen as coordinating behaviour and a series of learning and reflection events, consequently culminating in increased mutual understanding. Various conceptualisations of communication are explored and, together with several industry elicited factors that influence communication in business–IT alignment, are incorporated into a conceptual model informing the assessment method. This research developed, applied, and tested a method whereby organisations can assess the quality of the human communication between their business and IT personnel as part of the business–IT alignment endeavour. The aim of this method is to trigger reflection on communication by considering communication philosophy and practices in business–IT alignment. The method, termed the ‘Business-IT Communication Alignment Maturity Improvement Communication Alignment Maturity Improvement (CAMI) method’, is based on a maturity grid-based approach, which stems originally from process improvement in software development and quality management. This thesis is most closely aligned with the research performed by Maier, Eckert, and Clarkson (2004, 2006), who successfully applied the maturity grid-based approach to investigate, audit and assess communication within the engineering design process. The question addressed in this thesis is whether this approach can be successfully extrapolated to the business–IT alignment context and whether it would yield similar benefits. Furthermore, the issue of whether it would offer a practical method for use in organisations is also addressed. Having applied the CAMI method at a public sector organisation, this thesis proposes that the maturity grid-based approach can indeed be extrapolated to iv the business–IT alignment context, consequently offering a viable and practical method for assessing communication in organisations. In particular, the CAMI method allows organisations to capture both their current and their desired communication situations and to expose discrepancies between the perceptions held by their business and IT personnel. These results form a basis for action planning, strategizing, and, ultimately, interventions for improvement. In conclusion, the thesis discusses further application and extension possibilities for the assessment method.
- Full Text:
- Date Issued: 2016
- Authors: Coertze, Jacques Jacobus
- Date: 2016
- Subjects: Business communication , Management information systems
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/6740 , vital:21139
- Description: This thesis reports on the research undertaken to develop a method for organisations to assess human communication between their business and IT personnel as part of business–IT alignment. The research described in this thesis involves (i) a literature review in business–IT alignment and related fields, such as management studies and communication science; (ii) a Delphi study conducted among industry members, practitioners, and academics operating in the IT advisory, auditing and communication disciplines; and (iii) a case study of a public sector organisation in South Africa. By adopting a system-theoretic perspective on communication, this thesis proposes that communication in business–IT alignment can be seen as coordinating behaviour and a series of learning and reflection events, consequently culminating in increased mutual understanding. Various conceptualisations of communication are explored and, together with several industry elicited factors that influence communication in business–IT alignment, are incorporated into a conceptual model informing the assessment method. This research developed, applied, and tested a method whereby organisations can assess the quality of the human communication between their business and IT personnel as part of the business–IT alignment endeavour. The aim of this method is to trigger reflection on communication by considering communication philosophy and practices in business–IT alignment. The method, termed the ‘Business-IT Communication Alignment Maturity Improvement Communication Alignment Maturity Improvement (CAMI) method’, is based on a maturity grid-based approach, which stems originally from process improvement in software development and quality management. This thesis is most closely aligned with the research performed by Maier, Eckert, and Clarkson (2004, 2006), who successfully applied the maturity grid-based approach to investigate, audit and assess communication within the engineering design process. The question addressed in this thesis is whether this approach can be successfully extrapolated to the business–IT alignment context and whether it would yield similar benefits. Furthermore, the issue of whether it would offer a practical method for use in organisations is also addressed. Having applied the CAMI method at a public sector organisation, this thesis proposes that the maturity grid-based approach can indeed be extrapolated to iv the business–IT alignment context, consequently offering a viable and practical method for assessing communication in organisations. In particular, the CAMI method allows organisations to capture both their current and their desired communication situations and to expose discrepancies between the perceptions held by their business and IT personnel. These results form a basis for action planning, strategizing, and, ultimately, interventions for improvement. In conclusion, the thesis discusses further application and extension possibilities for the assessment method.
- Full Text:
- Date Issued: 2016
A proposed Christian-based governing model to increase the success of entrepreneurial ventures in South Africa
- Authors: Boshoff, Leslie Ian
- Date: 2016
- Subjects: Entrepreneurship -- South Africa , Success in business -- South Africa , Business -- Religious aspects , Sustainable development -- South Africa
- Language: English
- Type: Thesis , Doctoral , DBA
- Identifier: http://hdl.handle.net/10948/4827 , vital:20712
- Description: The Republic of South Africa (RSA) became a democracy when the African National Congress (ANC) came to power in 1994. However, more than twenty years after the apartheid era, the people of the RSA are highly politicised and society still shows an extremely high level of inequality in income that is aggravated by the lack of formal job opportunities in the country. Disturbingly, early-stage entrepreneurial activity in the RSA declined from 7.8 percent in 2008 to 5 percent in 2009. As a result, the low levels of entrepreneurial activity are partly responsible for the stagnation in the structural transformation of the economy. The economy remains dependent on sectors such as agriculture and mining where looting, instability, violence and rent-seeking are endemic in spite of plentiful natural resources. As a consequence of these factors, manufacturing is becoming increasingly uncompetitive and the economy is becoming increasingly less innovative. The RSA‟s government leaders should have used the strengths of the country to minimise or rectify the weaknesses of the extremely high levels of inequality in income and the lack of formal job opportunities. Instead, these leaders identified their supporters, satisfied their short-term consumption demands, distributed jobs to the party faithful and provided social welfare to the poor. Additionally, the majority of school leavers are not pursuing tertiary studies but, with limited or little education, they still have to form part of the potential labour force of the future. The youth employment rate for 15 to 24 year-olds, in the RSA, is as low as 12.5 percent. Again, this highlights the importance of finding alternative ways to increase the population‟s participation in the economy, probably through some form of entrepreneurship. The purpose of this study was to develop a theoretical model with the main objective being to identify the factors (variables) that will promote growth, sustainability and good governance in Christian-owned Small, Micro and Medium Enterprises (SMME) within the RSA. Business is commonly viewed as a secular pursuit and religious people, particularly in Western societies, have a narrow view of the conceptual and practical application of their faith and spirituality in their businesses. As a result, the potential of businesses to influence communities, particularly with regard to issues such as social iniquities and cultural reform, good governance, responsible business behaviour, social capital, spiritual intelligence (SQ) and Christian entrepreneurship orientation appear to be, at worst, more or less irrelevant and, at best, greatly under-valued and under-utilised. The intersection of these constructs provides an understanding of how an entrepreneur‟s heightened consciousness in terms of his/her personal values and beliefs can affect his or her business activities and crucial characteristics of the entrepreneurial process, such as the recognition of opportunities, the creation of new ventures, as well as the operation and growth of these business ventures. This study uncovered a number of themes that shed light on how Christian SMME owner-managers rationalise the everyday dealings of their business lives as an expression of their faith. This study is an expression of a complex phenomenon that is extremely relevant in the present day and sharpens the focus on the important role that religious faith has to play in the field of business outcomes. Many Christian entrepreneurs express a motivational need to give back to their communities, customers and other stakeholders of the business venture. Christian entrepreneurs value intrinsic factors like purpose, passionate work and personal calling above wealth, fame, power, money, and recognition. A combination of Christian character traits forms the backbone of a Christian‟s internal power and purpose. God created people to glorify Him and this purpose is achieved through the fulfilling of a personal calling. A calling is often accompanied by a conviction of divine influence and the vocation in which one customarily engages. The call to the Christian entrepreneur is to be the salt and light in an environment (Mathew 5:13) like RSA, that is not conducive to entrepreneurial behaviour, where unemployment is very high, infrastructure is buckling under the pressures of bad management and corruption is rife.
- Full Text:
- Date Issued: 2016
- Authors: Boshoff, Leslie Ian
- Date: 2016
- Subjects: Entrepreneurship -- South Africa , Success in business -- South Africa , Business -- Religious aspects , Sustainable development -- South Africa
- Language: English
- Type: Thesis , Doctoral , DBA
- Identifier: http://hdl.handle.net/10948/4827 , vital:20712
- Description: The Republic of South Africa (RSA) became a democracy when the African National Congress (ANC) came to power in 1994. However, more than twenty years after the apartheid era, the people of the RSA are highly politicised and society still shows an extremely high level of inequality in income that is aggravated by the lack of formal job opportunities in the country. Disturbingly, early-stage entrepreneurial activity in the RSA declined from 7.8 percent in 2008 to 5 percent in 2009. As a result, the low levels of entrepreneurial activity are partly responsible for the stagnation in the structural transformation of the economy. The economy remains dependent on sectors such as agriculture and mining where looting, instability, violence and rent-seeking are endemic in spite of plentiful natural resources. As a consequence of these factors, manufacturing is becoming increasingly uncompetitive and the economy is becoming increasingly less innovative. The RSA‟s government leaders should have used the strengths of the country to minimise or rectify the weaknesses of the extremely high levels of inequality in income and the lack of formal job opportunities. Instead, these leaders identified their supporters, satisfied their short-term consumption demands, distributed jobs to the party faithful and provided social welfare to the poor. Additionally, the majority of school leavers are not pursuing tertiary studies but, with limited or little education, they still have to form part of the potential labour force of the future. The youth employment rate for 15 to 24 year-olds, in the RSA, is as low as 12.5 percent. Again, this highlights the importance of finding alternative ways to increase the population‟s participation in the economy, probably through some form of entrepreneurship. The purpose of this study was to develop a theoretical model with the main objective being to identify the factors (variables) that will promote growth, sustainability and good governance in Christian-owned Small, Micro and Medium Enterprises (SMME) within the RSA. Business is commonly viewed as a secular pursuit and religious people, particularly in Western societies, have a narrow view of the conceptual and practical application of their faith and spirituality in their businesses. As a result, the potential of businesses to influence communities, particularly with regard to issues such as social iniquities and cultural reform, good governance, responsible business behaviour, social capital, spiritual intelligence (SQ) and Christian entrepreneurship orientation appear to be, at worst, more or less irrelevant and, at best, greatly under-valued and under-utilised. The intersection of these constructs provides an understanding of how an entrepreneur‟s heightened consciousness in terms of his/her personal values and beliefs can affect his or her business activities and crucial characteristics of the entrepreneurial process, such as the recognition of opportunities, the creation of new ventures, as well as the operation and growth of these business ventures. This study uncovered a number of themes that shed light on how Christian SMME owner-managers rationalise the everyday dealings of their business lives as an expression of their faith. This study is an expression of a complex phenomenon that is extremely relevant in the present day and sharpens the focus on the important role that religious faith has to play in the field of business outcomes. Many Christian entrepreneurs express a motivational need to give back to their communities, customers and other stakeholders of the business venture. Christian entrepreneurs value intrinsic factors like purpose, passionate work and personal calling above wealth, fame, power, money, and recognition. A combination of Christian character traits forms the backbone of a Christian‟s internal power and purpose. God created people to glorify Him and this purpose is achieved through the fulfilling of a personal calling. A calling is often accompanied by a conviction of divine influence and the vocation in which one customarily engages. The call to the Christian entrepreneur is to be the salt and light in an environment (Mathew 5:13) like RSA, that is not conducive to entrepreneurial behaviour, where unemployment is very high, infrastructure is buckling under the pressures of bad management and corruption is rife.
- Full Text:
- Date Issued: 2016
Addressing gender-based violence in the age of Aids: rural youth engaging peers through social media
- Authors: Geldenhuys, Martha Maria
- Date: 2016
- Subjects: AIDS (Disease) in adolescence -- South Africa -- KwaZulu-Natal -- Attitudes , Violence -- Sex differences , Digital storytelling , Social media -- South Africa -- KwaZulu-Natal
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/12469 , vital:27069
- Description: This study responds to the following research question: How might rural school youth engage peers using social media in a participatory cultures framework to contribute to addressing gender-based violence in their community? This question is supported by the following secondary questions: How do rural school youth understand gender-based violence in their community. how might rural school youth use social media within a participatory cultures framework to engage peers in addressing GBV How can rural school youth engage with their peers via social media to facilitate youth agency in a participatory cultures framework This qualitative study is positioned in a critical paradigm and employs a visual participatory research methodology to contribute to addressing gender-based violence in the age of HIV and AIDS. The participants in this study are five learners (3 boys and 2 girls) with five of their peers (3 boys and 2 girls) from a secondary school in rural Vulindlela in KwaZulu-Natal, purposively selected from Grade 9 classes. Digital storytelling was employed as the main visual method of data generation to express the participants’ understanding of, and solutions to, genderbased violence. The stories were used by the participants to engage their peers around the topic via social media and to enable them to reflect on their own agency. The study draws on Jenkins’ theory of participatory cultures as a heoretical framework. Thematic analysis was applied to make meaning of the findings. The findings show that rural school youth understand gender-based violence (GBV) as a complex problem. Youthful learners are able to competently apply social media to address GBV and engage their peers through social media – hifting the power to participate as agents of change.The findings have implications for youth, the school, and the community. The youth are seen as knowledgeable actors who should inform intervention programmes aimed at social change. Social media can offer an engaging environment for peer learning and support. For digital participation, the youth need to acquire digital skills at school which could be integrated throughout the curriculum, drawing on participatory cultures. In the community, youth as knowledge producers are competent in leading, guiding, and instructing community members using social media spaces as more people have access to inexpensive digital technology that allows them to participate in community intervention programmes aimed at social change. I conclude by arguing that youth can express lived realties on GBV and solutions to GBV through visual methods such as digital storytelling. Their engagement on social media such as Facebook can be viewed as intervention by assuming agency through a guided process of solving community problems collaboratively with peers through the process of participatory cultures. This democratic process strengthens agency for community benefit and highlights a new youth and peer culture where youth circulate new and self-made content aimed at social action through their continuous reflection – a shift in power as the voices and actions of youth are acknowledged.
- Full Text:
- Date Issued: 2016
Addressing gender-based violence in the age of Aids: rural youth engaging peers through social media
- Authors: Geldenhuys, Martha Maria
- Date: 2016
- Subjects: AIDS (Disease) in adolescence -- South Africa -- KwaZulu-Natal -- Attitudes , Violence -- Sex differences , Digital storytelling , Social media -- South Africa -- KwaZulu-Natal
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/12469 , vital:27069
- Description: This study responds to the following research question: How might rural school youth engage peers using social media in a participatory cultures framework to contribute to addressing gender-based violence in their community? This question is supported by the following secondary questions: How do rural school youth understand gender-based violence in their community. how might rural school youth use social media within a participatory cultures framework to engage peers in addressing GBV How can rural school youth engage with their peers via social media to facilitate youth agency in a participatory cultures framework This qualitative study is positioned in a critical paradigm and employs a visual participatory research methodology to contribute to addressing gender-based violence in the age of HIV and AIDS. The participants in this study are five learners (3 boys and 2 girls) with five of their peers (3 boys and 2 girls) from a secondary school in rural Vulindlela in KwaZulu-Natal, purposively selected from Grade 9 classes. Digital storytelling was employed as the main visual method of data generation to express the participants’ understanding of, and solutions to, genderbased violence. The stories were used by the participants to engage their peers around the topic via social media and to enable them to reflect on their own agency. The study draws on Jenkins’ theory of participatory cultures as a heoretical framework. Thematic analysis was applied to make meaning of the findings. The findings show that rural school youth understand gender-based violence (GBV) as a complex problem. Youthful learners are able to competently apply social media to address GBV and engage their peers through social media – hifting the power to participate as agents of change.The findings have implications for youth, the school, and the community. The youth are seen as knowledgeable actors who should inform intervention programmes aimed at social change. Social media can offer an engaging environment for peer learning and support. For digital participation, the youth need to acquire digital skills at school which could be integrated throughout the curriculum, drawing on participatory cultures. In the community, youth as knowledge producers are competent in leading, guiding, and instructing community members using social media spaces as more people have access to inexpensive digital technology that allows them to participate in community intervention programmes aimed at social change. I conclude by arguing that youth can express lived realties on GBV and solutions to GBV through visual methods such as digital storytelling. Their engagement on social media such as Facebook can be viewed as intervention by assuming agency through a guided process of solving community problems collaboratively with peers through the process of participatory cultures. This democratic process strengthens agency for community benefit and highlights a new youth and peer culture where youth circulate new and self-made content aimed at social action through their continuous reflection – a shift in power as the voices and actions of youth are acknowledged.
- Full Text:
- Date Issued: 2016
Against all odds: the effect of electoral violence on the political participation of citizens: a case study of voters in Nairobi
- Authors: Plata, Stephanie
- Date: 2016
- Subjects: Elections -- Kenya -- Nairobi , Political participation -- Kenya -- Nairobi , Political violence -- Kenya -- Nairobi
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/5589 , vital:20913
- Description: Competitive national elections can play a significant role in the consolidation process of developing and established democracies alike. Nevertheless, if not handled adequately, they have the potential to bring long-existing, existential conflict lines to the surface. This electoral conflict, becoming manifest in election violence, has the potential to shy people off from voting and negatively affect their attitude towards elections and democracy in general. The present study examined the ways in which violent electoral conflict affected the political participation and the personal attitudes towards democracy of ordinary Kenyan citizens. Kenya has experienced violent electoral conflict repeatedly since the re-introduction of competitive elections in 1992 and became one of its prime examples due to the devastating 2008 post-election clashes. In order to answer the research questions, 32 semi-structured interviews with 34 victims of electoral violence coming from four main ‘hotspot areas’ of the 2008 post-election violence as well as four expert interviews were conducted. The study finds that the experience of violent electoral conflict led to diametrically opposed reactions in the behaviour of political participation among respondents. About two-thirds of them indicated a change in their behaviour of political participation. With 33% of the respondents found to be “participating more”, this group even outnumbers its “participating less” counterpart (30%). This finding is rather surprising as the experience of electoral violence is usually associated with the tendency to shy off from political participation, not only in Kenya. Based on their attitudinal dispositions towards democracy in general and towards democracy in Kenya more specifically, as well as towards Kenyan elections, politics and politicians, a fourfold typology of Kenyan citizens was developed from the sample. It includes: the voting citizen, the resigned citizen, the passive citizen, and the active citizen. The voting citizen with no further interest in politics or political participation was found to be the most prevalent type of citizen in the sample. Attention needs to be taken towards the resigned citizen, which could, in case of further violent electoral conflict and the continuing marginalization of specific ethnic groups, cause a threat to the stabilization process of Kenya’s democracy. Contributions of this study were in designing a destination identity framework as well as in discovering the identity of the city of Nelson Mandela Bay. Directions for future studies include the possibility to conduct a qualitative study on place identity so as to obtain a more nuanced understanding of sub-identities in the city.
- Full Text:
- Date Issued: 2016
- Authors: Plata, Stephanie
- Date: 2016
- Subjects: Elections -- Kenya -- Nairobi , Political participation -- Kenya -- Nairobi , Political violence -- Kenya -- Nairobi
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/5589 , vital:20913
- Description: Competitive national elections can play a significant role in the consolidation process of developing and established democracies alike. Nevertheless, if not handled adequately, they have the potential to bring long-existing, existential conflict lines to the surface. This electoral conflict, becoming manifest in election violence, has the potential to shy people off from voting and negatively affect their attitude towards elections and democracy in general. The present study examined the ways in which violent electoral conflict affected the political participation and the personal attitudes towards democracy of ordinary Kenyan citizens. Kenya has experienced violent electoral conflict repeatedly since the re-introduction of competitive elections in 1992 and became one of its prime examples due to the devastating 2008 post-election clashes. In order to answer the research questions, 32 semi-structured interviews with 34 victims of electoral violence coming from four main ‘hotspot areas’ of the 2008 post-election violence as well as four expert interviews were conducted. The study finds that the experience of violent electoral conflict led to diametrically opposed reactions in the behaviour of political participation among respondents. About two-thirds of them indicated a change in their behaviour of political participation. With 33% of the respondents found to be “participating more”, this group even outnumbers its “participating less” counterpart (30%). This finding is rather surprising as the experience of electoral violence is usually associated with the tendency to shy off from political participation, not only in Kenya. Based on their attitudinal dispositions towards democracy in general and towards democracy in Kenya more specifically, as well as towards Kenyan elections, politics and politicians, a fourfold typology of Kenyan citizens was developed from the sample. It includes: the voting citizen, the resigned citizen, the passive citizen, and the active citizen. The voting citizen with no further interest in politics or political participation was found to be the most prevalent type of citizen in the sample. Attention needs to be taken towards the resigned citizen, which could, in case of further violent electoral conflict and the continuing marginalization of specific ethnic groups, cause a threat to the stabilization process of Kenya’s democracy. Contributions of this study were in designing a destination identity framework as well as in discovering the identity of the city of Nelson Mandela Bay. Directions for future studies include the possibility to conduct a qualitative study on place identity so as to obtain a more nuanced understanding of sub-identities in the city.
- Full Text:
- Date Issued: 2016
An investigation of the morphological and electrochemical properties of spinel cathode oxide materials used in li-ion batteries
- Authors: Snyders, Charmelle
- Date: 2016
- Subjects: Lithium ion batteries Cathodes
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/12929 , vital:27135
- Description: Li-ion batteries have become the more dominant battery type used in portable electronic devices such as cell phones, computers and more recently their application in full electric vehicles (EV). Li-ion batteries have many advantages over the traditional rechargeable systems (Pb-acid and Ni-MH) such as their higher energy density, low self-discharge, long capacity cycle life and relatively maintenance free. Due to their commercial advantages, a lot of research is done in developing new novel Li-ion electrode materials, improving existing ones and to reduce manufacturing costs in order to make them more cost effective in their applications. This study looked at the cathode material chemistry that has a typical spinel manganese oxide (LiMn2O4) type structure. For comparison the study also considered the influence of doping the phase with various metals such as Al, Mg, Co and Ni that were made as precursors using various carboxylic acids (Citric, Ascorbic, Succinic and Poly-acrylic acid) from a sol-gel process. Traditional batch methods of synthesizing the electrode material is costly and do not necessarily provide optimized electrochemical performance. Alternative continuous less energy intensive methods would help reduce the costs of the preparation of the electrode materials. This study investigated the influence of two synthesis techniques on the materials physical and electrochemical characteristics. These synthesis methods included the use of a typical batch sol-gel method and the continuous spray-drying technique. The spinel materials were prepared and characterized by Powder X-Ray Diffraction (PXRD) to confirm the formation of various phases during the synthesis process. In addition, in-situ PXRD techniques were used to track the phase changes that occurred in the typical batch synthesis process from a sol-gel mixture to the final crystalline spinel oxide. The materials were also characterized by thermal gravimetric analysis (TGA), whereby the materials decomposition mechanisms were observed as the precursor was gradually heated to the final oxide. These synthesized materials prepared under various conditions were then used to build suitable Li-ion coin type of cells, whereby their electrochemical properties were tested by simple capacity tests and electrochemical impedance spectroscopy (EIS). EIS measurements were done on the built cells with the various materials at various charge voltages. TG analysis showed that the materials underwent multiple decomposition steps upon heating for the doped lithium manganese oxides, whereas the undoped oxide showed only a single decomposition step. The results showed that all the materials achieved their weight loss below 400 °C, and that the final spinel oxide had already formed. The in-situ PXRD analysis showed the progression of the phase transitions where certain of the materials changed from a crystalline precursor to an amorphous intermediate phase and then finally to the spinel cathode oxide (Li1.03Mg0.2Mn1.77O4, and LiCo1.09Mn0.91O4). For other materials, the precursor would start as an amorphous phase, and then upon heating, convert into an impure intermediate phase (Mn2O3) before forming the final spinel oxide (Li1.03Mn1.97O4 and LiNi0.5Mn1.5O4). The in-situ study also showed the increases in the materials respective lattice parameters of the crystalline unit cells upon heating and the significant increases in their crystallite sizes when heated above 600 °C. Hence the results implied that a type of sintering of the particles would occur at temperatures above 600 °C, thereby increasing the respective crystallite size. The study showed that the cathode active materials made by the sol-gel spray-drying method would give a material that had a significantly larger surface area and a smaller crystallite size when compared to the materials made by the batch process. The electrochemical analysis showed that there was only a slight increase in the discharge capacities of the cells made with the spray-drying technique when compared to the cells made with the materials from the batch sol-gel technique. Whereas, the EIS study showed that there were distinct differences in the charging behavior of the cells made with the various materials using different synthesis techniques. The EIS results showed that there was a general decrease in the cells charge transfer resistance (Rct) as the charge potential increased regardless of the synthesis method used for the various materials. The results also showed that the lithium-ion diffusion coefficient (DLi) obtained from EIS measurements were in most of the samples higher for the cathode materials that had a larger surface area. This implied that the Li-ion could diffuse at a faster rate through the bulk material. The study concluded that by optimizing the synthesis process in terms of the careful control of the thermal parameters, the Li-ion batteries‟ cathode active material of the manganese spinel type could be optimized and be manufactured by using a continuous flow micro spray process.
- Full Text:
- Date Issued: 2016
- Authors: Snyders, Charmelle
- Date: 2016
- Subjects: Lithium ion batteries Cathodes
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/12929 , vital:27135
- Description: Li-ion batteries have become the more dominant battery type used in portable electronic devices such as cell phones, computers and more recently their application in full electric vehicles (EV). Li-ion batteries have many advantages over the traditional rechargeable systems (Pb-acid and Ni-MH) such as their higher energy density, low self-discharge, long capacity cycle life and relatively maintenance free. Due to their commercial advantages, a lot of research is done in developing new novel Li-ion electrode materials, improving existing ones and to reduce manufacturing costs in order to make them more cost effective in their applications. This study looked at the cathode material chemistry that has a typical spinel manganese oxide (LiMn2O4) type structure. For comparison the study also considered the influence of doping the phase with various metals such as Al, Mg, Co and Ni that were made as precursors using various carboxylic acids (Citric, Ascorbic, Succinic and Poly-acrylic acid) from a sol-gel process. Traditional batch methods of synthesizing the electrode material is costly and do not necessarily provide optimized electrochemical performance. Alternative continuous less energy intensive methods would help reduce the costs of the preparation of the electrode materials. This study investigated the influence of two synthesis techniques on the materials physical and electrochemical characteristics. These synthesis methods included the use of a typical batch sol-gel method and the continuous spray-drying technique. The spinel materials were prepared and characterized by Powder X-Ray Diffraction (PXRD) to confirm the formation of various phases during the synthesis process. In addition, in-situ PXRD techniques were used to track the phase changes that occurred in the typical batch synthesis process from a sol-gel mixture to the final crystalline spinel oxide. The materials were also characterized by thermal gravimetric analysis (TGA), whereby the materials decomposition mechanisms were observed as the precursor was gradually heated to the final oxide. These synthesized materials prepared under various conditions were then used to build suitable Li-ion coin type of cells, whereby their electrochemical properties were tested by simple capacity tests and electrochemical impedance spectroscopy (EIS). EIS measurements were done on the built cells with the various materials at various charge voltages. TG analysis showed that the materials underwent multiple decomposition steps upon heating for the doped lithium manganese oxides, whereas the undoped oxide showed only a single decomposition step. The results showed that all the materials achieved their weight loss below 400 °C, and that the final spinel oxide had already formed. The in-situ PXRD analysis showed the progression of the phase transitions where certain of the materials changed from a crystalline precursor to an amorphous intermediate phase and then finally to the spinel cathode oxide (Li1.03Mg0.2Mn1.77O4, and LiCo1.09Mn0.91O4). For other materials, the precursor would start as an amorphous phase, and then upon heating, convert into an impure intermediate phase (Mn2O3) before forming the final spinel oxide (Li1.03Mn1.97O4 and LiNi0.5Mn1.5O4). The in-situ study also showed the increases in the materials respective lattice parameters of the crystalline unit cells upon heating and the significant increases in their crystallite sizes when heated above 600 °C. Hence the results implied that a type of sintering of the particles would occur at temperatures above 600 °C, thereby increasing the respective crystallite size. The study showed that the cathode active materials made by the sol-gel spray-drying method would give a material that had a significantly larger surface area and a smaller crystallite size when compared to the materials made by the batch process. The electrochemical analysis showed that there was only a slight increase in the discharge capacities of the cells made with the spray-drying technique when compared to the cells made with the materials from the batch sol-gel technique. Whereas, the EIS study showed that there were distinct differences in the charging behavior of the cells made with the various materials using different synthesis techniques. The EIS results showed that there was a general decrease in the cells charge transfer resistance (Rct) as the charge potential increased regardless of the synthesis method used for the various materials. The results also showed that the lithium-ion diffusion coefficient (DLi) obtained from EIS measurements were in most of the samples higher for the cathode materials that had a larger surface area. This implied that the Li-ion could diffuse at a faster rate through the bulk material. The study concluded that by optimizing the synthesis process in terms of the careful control of the thermal parameters, the Li-ion batteries‟ cathode active material of the manganese spinel type could be optimized and be manufactured by using a continuous flow micro spray process.
- Full Text:
- Date Issued: 2016
Anti-diabetic and phytochemical analysis of sutherlandia frutescens extracts
- Authors: Adefuye, Ogheneochuko Janet
- Date: 2016
- Subjects: Medicinal plants -- Africa , Traditional medicine -- Africa , Herbs -- Therapeutic use -- Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/3549 , vital:20441
- Description: In Africa, the importance of medicinal plants in folklore medicine and their contribution to primary healthcare is well recognized. Across the continent, local herbal mixtures still provide the only therapeutic option for about 80% of the population. The vast floral diversity and the intrinsic ethnobotanical knowledge has been the backbone of localized traditional herbal medical practices. In Africa, an estimated 5400 of the 60000 described plant taxa possess over 16300 therapeutic uses. Similarly, with a therapeutic flora comprising of approximately 650 species, herbal medical practitioners in South Africa, make use of a plethora of plants to treat different human diseases and infections. Over the years, studies have identified numerous plant species with potential against chronic metabolic diseases including type 2 diabetes mellitus (T2DM). Globally, the incidence and prevalence of T2DM have reached epidemic proportions affecting people of all ages, nationalities and ethnicity. Considered the fourth leading cause of deaths by disease, T2DM is a global health crisis with an estimated diagnosis and mortality frequency of 1 every 5 seconds and 1 every 7 seconds respectively. Though the exact pathophysiology of T2DM is not entirely understood, initial peripheral insulin resistance in adipose tissue, liver, and skeletal muscle with subsequent pancreatic β-cell dysfunction resulting from an attempt to compensate for insulin resistance is a common feature of the disease. The current approach to treating T2DM is the use of oral antidiabetic agents (OAAs), insulin, and incretin-based drugs in an attempt to achieve glycaemic control and maintain glucose homeostasis. However, conventional anti-T2DM drugs have been shown to have limited efficacies and serious adverse effects. Hence, the need for newer, more efficacious and safer anti-T2DM agents. Sutherlandia frutescens subsp. microphylla is a flowering shrub of the pea family (Fabaceae/Leguminaceae) found mainly in the Western Cape and Karoo regions of Southern Africa. Concoctions of various parts of the plant are used in the management of different ailments including T2DM. However, despite extensive biological and pharmacological studies, few analyses exist of the chemical constituents of S. frutescens and no Triple Time of Flight Liquid Chromatography with Mass Spectrometry (Triple TOF LC/MS/MS) analysis has been performed. The initial aim of this study was to investigate the phytochemical profile of hot aqueous, cold aqueous, 80% ethanolic, 100% ethanolic, 80% methanolic and 100% methanolic extracts of a single source S. frutescens plant material using colorimetric and spectrophotometric analysis. The hot aqueous extractant was found to be the best extractant for S. frutescens, yielding 1.99 g of crude extract from 16 g fresh powdered plant material. This data suggests that application of heat and water as the extractant (hot aqueous) could play a vital role in extraction of bioactive compounds from S. frutescens and also justifies the traditional use of a tea infusion of S. frutescens. Colorimetric analysis revealed the presence of flavonoids, flavonols, tannins, and phenols in all extracts with varying intensity. The organic extracts 100% methanol, 80% and 100% ethanol exhibited high color intensity (+++) for flavonoids and flavonols respectively, while all the extracts exhibited a moderate color intensity (++) for tannins and phenols. Spectrophotometric analysis of S. frutescens extracts revealed that all the organic extracts contained a significantly higher concentration (in mg/g of extract) of flavonols and tannins when compared to the aqueous extracts. All extracts contained approximately equal levels of phenols. These data confirm the presence of all four groups of bioactive phytocompounds in the S. frutescens extracts used in this study, and also confirm that different solvent extractants possess the capability to differentially extract specific groups of phytocompounds. in individual extracts. Further comparison of these compounds with online databases of anti-diabetic phytocompounds led to the preliminary identification of 10 possible anti-diabetic compounds; α-Pinene, Limonene, Sabinene, Carvone, Myricetin, Rutin, Stigmasterol, Emodin, Sarpagine and Hypoglycin B in crude and solid phase extraction (SPE) fractions of S. frutesecens. Furthermore, using two hepatic cell lines (Chang and HepG2) as an in-vtro model system, the anti-T2DM properties of crude aqueous and organic extracts of S. frutescents was investigated and compared. Both aqueous and organic extracts of S. frutescens were found to decrease gluconeogenesis, increase glucose uptake and decrease lipid accumulation (Triacylglycerol, Diacylglycerol, and Monoacylglycerol) in Chang and HepG2 hepatic cell cultures made insulin resistant (IR) following exposure to high concentration of insulin and fructose. Using real-time quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), the aqueous and organic extracts of S. frutescens were confirmed to regulate the expression of Vesicle-associated membrane protein 3 (VAMP3), Mitogen-activated protein kinase 8 (MAPK8), and Insulin receptor substrate 1 (IRS1) in insulin resistant hepatic cells. IR-mediated downregulation of VAMP3, MAPK8, and IRS1 mRNA in IR HepG2 hepatic cell cultures was reversed in the presence of aqueous and organic extracts of S. frutescens. The hot aqueous extract displayed the highest activity in all the assays, while all the organic extracts displayed similar potency. In conclusion, this study reports that aqueous and organic extracts of S. frutescens possess numerous anti-diabetic compounds that can be further investigated for the development of new, more efficacious and less toxic anti-diabetic agents. The presence of multiple compounds in a single extract does suggest a synergistic or combinatorial therapeutic effect. These findings support the burgeoning body of in-vivo and in-vitro literature evidence on the anti-diabetic properties of S. frutescens and its use in folklore medicine.
- Full Text:
- Date Issued: 2016
- Authors: Adefuye, Ogheneochuko Janet
- Date: 2016
- Subjects: Medicinal plants -- Africa , Traditional medicine -- Africa , Herbs -- Therapeutic use -- Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/3549 , vital:20441
- Description: In Africa, the importance of medicinal plants in folklore medicine and their contribution to primary healthcare is well recognized. Across the continent, local herbal mixtures still provide the only therapeutic option for about 80% of the population. The vast floral diversity and the intrinsic ethnobotanical knowledge has been the backbone of localized traditional herbal medical practices. In Africa, an estimated 5400 of the 60000 described plant taxa possess over 16300 therapeutic uses. Similarly, with a therapeutic flora comprising of approximately 650 species, herbal medical practitioners in South Africa, make use of a plethora of plants to treat different human diseases and infections. Over the years, studies have identified numerous plant species with potential against chronic metabolic diseases including type 2 diabetes mellitus (T2DM). Globally, the incidence and prevalence of T2DM have reached epidemic proportions affecting people of all ages, nationalities and ethnicity. Considered the fourth leading cause of deaths by disease, T2DM is a global health crisis with an estimated diagnosis and mortality frequency of 1 every 5 seconds and 1 every 7 seconds respectively. Though the exact pathophysiology of T2DM is not entirely understood, initial peripheral insulin resistance in adipose tissue, liver, and skeletal muscle with subsequent pancreatic β-cell dysfunction resulting from an attempt to compensate for insulin resistance is a common feature of the disease. The current approach to treating T2DM is the use of oral antidiabetic agents (OAAs), insulin, and incretin-based drugs in an attempt to achieve glycaemic control and maintain glucose homeostasis. However, conventional anti-T2DM drugs have been shown to have limited efficacies and serious adverse effects. Hence, the need for newer, more efficacious and safer anti-T2DM agents. Sutherlandia frutescens subsp. microphylla is a flowering shrub of the pea family (Fabaceae/Leguminaceae) found mainly in the Western Cape and Karoo regions of Southern Africa. Concoctions of various parts of the plant are used in the management of different ailments including T2DM. However, despite extensive biological and pharmacological studies, few analyses exist of the chemical constituents of S. frutescens and no Triple Time of Flight Liquid Chromatography with Mass Spectrometry (Triple TOF LC/MS/MS) analysis has been performed. The initial aim of this study was to investigate the phytochemical profile of hot aqueous, cold aqueous, 80% ethanolic, 100% ethanolic, 80% methanolic and 100% methanolic extracts of a single source S. frutescens plant material using colorimetric and spectrophotometric analysis. The hot aqueous extractant was found to be the best extractant for S. frutescens, yielding 1.99 g of crude extract from 16 g fresh powdered plant material. This data suggests that application of heat and water as the extractant (hot aqueous) could play a vital role in extraction of bioactive compounds from S. frutescens and also justifies the traditional use of a tea infusion of S. frutescens. Colorimetric analysis revealed the presence of flavonoids, flavonols, tannins, and phenols in all extracts with varying intensity. The organic extracts 100% methanol, 80% and 100% ethanol exhibited high color intensity (+++) for flavonoids and flavonols respectively, while all the extracts exhibited a moderate color intensity (++) for tannins and phenols. Spectrophotometric analysis of S. frutescens extracts revealed that all the organic extracts contained a significantly higher concentration (in mg/g of extract) of flavonols and tannins when compared to the aqueous extracts. All extracts contained approximately equal levels of phenols. These data confirm the presence of all four groups of bioactive phytocompounds in the S. frutescens extracts used in this study, and also confirm that different solvent extractants possess the capability to differentially extract specific groups of phytocompounds. in individual extracts. Further comparison of these compounds with online databases of anti-diabetic phytocompounds led to the preliminary identification of 10 possible anti-diabetic compounds; α-Pinene, Limonene, Sabinene, Carvone, Myricetin, Rutin, Stigmasterol, Emodin, Sarpagine and Hypoglycin B in crude and solid phase extraction (SPE) fractions of S. frutesecens. Furthermore, using two hepatic cell lines (Chang and HepG2) as an in-vtro model system, the anti-T2DM properties of crude aqueous and organic extracts of S. frutescents was investigated and compared. Both aqueous and organic extracts of S. frutescens were found to decrease gluconeogenesis, increase glucose uptake and decrease lipid accumulation (Triacylglycerol, Diacylglycerol, and Monoacylglycerol) in Chang and HepG2 hepatic cell cultures made insulin resistant (IR) following exposure to high concentration of insulin and fructose. Using real-time quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), the aqueous and organic extracts of S. frutescens were confirmed to regulate the expression of Vesicle-associated membrane protein 3 (VAMP3), Mitogen-activated protein kinase 8 (MAPK8), and Insulin receptor substrate 1 (IRS1) in insulin resistant hepatic cells. IR-mediated downregulation of VAMP3, MAPK8, and IRS1 mRNA in IR HepG2 hepatic cell cultures was reversed in the presence of aqueous and organic extracts of S. frutescens. The hot aqueous extract displayed the highest activity in all the assays, while all the organic extracts displayed similar potency. In conclusion, this study reports that aqueous and organic extracts of S. frutescens possess numerous anti-diabetic compounds that can be further investigated for the development of new, more efficacious and less toxic anti-diabetic agents. The presence of multiple compounds in a single extract does suggest a synergistic or combinatorial therapeutic effect. These findings support the burgeoning body of in-vivo and in-vitro literature evidence on the anti-diabetic properties of S. frutescens and its use in folklore medicine.
- Full Text:
- Date Issued: 2016
Benzoyl isothiocyanates derived ligands as potential HIV-1 protease inhibitors and their reactions with gold ions
- Authors: Odame, Felix
- Date: 2016
- Subjects: HIV (Viruses) -- Enzymes Enzyme inhibitors -- Research , Pharmaceutical chemistry Biochemistry
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/33228 , vital:32585
- Description: The synthesis and evaluation of benzoyl isothiocyanate derivatives as potential HIV-1 protease inhibitors is presented. The ligands were first designed to fit the protease active site using Autodock 4.2. The design was based on the deNOVO method of drug design in which the active site coordinates from the crystal structure of protease bound to ritonavir was used. An attempt to access the scaffolds designed initially led to the formation of 2,2,4-trimethyl 2,3-dihydro-1H-1,5-benzodiazepin-5-ium isophthalate and 2-2-(3-methylphenyl-1Hbenzimidazole which could not be converted to the desired intermediate. A further attempt led to formation of amino acid and amino acid ester derivatives of benzoyl isothiocyanates which have been fully characterized and the reasons why the desired intermediates were not readily accessible explained. Scaffolds based on the benzoyl isothiocyanate derivatives of structurally diverse diamines were then screened. Sixty compounds have been synthesized and fully characterized using elemental analysis, spectroscopy, GC-MS and twenty-six crystal structures have been discussed. The DFT transition state studies of 11-phenyl- 1,8,10,12-tetraazatricyclo[7.4.0.02,7]trideca-2(7),3,5,9,11-pentaene-13-thione (20), N-(1Hbenzimidazol-2-yl)benzamide (21), 3-(1,3-benzothiazol-2-yl)-1-(benzoyl)thiourea (23), and N-[(9E)-8,10,17-triazatetracyclo[8.7.0.02,7.011,16]heptadeca-1(17),2,4,6,11(16),12,14-heptaen-9-ylidene] benzamide (39), have been carried out and their detailed density functional theory reaction mechanism have be computed. The Bernly algorithm was used in the determination of saddle points (transtions states), and the intrinsic reaction coordinates leading to the determination of intermediates were traced and optimized to a global minimum or in some cases a local minimum was obtained. The cell viability tests of diamine derivatives which was done by exposing white blood cells to the compounds (inhibitors) at 37 °C and a pH of 7.4 showed that 1-(4-bromobenzoyl)-3-[2- ({[(4-bromophenyl)formamido]methanethioyl}amino)phenyl]thiourea (46), 1-(3-chloro benzoyl)-3-[2-({[(3-chlorophenyl)formamido]methanethioyl}amino)phenyl]thiourea (48), 1- (3-bromobenzoyl)-3-[2-({[(3-bromophenyl)formamido]methanethioyl}amino)phenyl] thiourea (49) and 3-benzoyl-1-(4-{[(phenylformamido)methanethioyl]amino}butyl)thiourea (54), in that group of compounds were cytotoxic with EC50 values of 17.04 ± 9.75 μM, 69.20± 38.16 μM, 35.90 ± 20.55 μM and 68.37 ± 26.45 μM, respectively. 4-Bromo-N-[(9E)-8,10,17-triazatetracyclo[8.7.0.02,7.011,16]heptadeca-1(17),2,4,6,11(16),12,14-heptaen-9-ylidene] benzamide (32), 4-methoxy-N-[(9E)-8,10,17-triazatetracyclo[8.7.0.02,7.011,16]heptadeca-1(17),2,4,6,11(16),12,14-heptaen-9-ylidene]benzamide (33) and 3-chloro-N-[(9E)-8,10,17-triazatetracyclo[8.7.0.02,7.011,16]heptadeca-1(17),2,4,6,11(16),12,14-heptaen-9-ylidene] benzamide (37) were also cytotoxic giving EC50 values of 45.47 ± 21.92, 45.09 ±13.79 and 74.94 ± 13.17 μM, respectively. 3-(1,3-Benzothiazol-2-yl)-1-(3-bromobenzoyl)thiourea (31) and 3-(1,3-benzothiazoyl-2-yl)-1-(4-nitrobenzoyl)thiourea (30) derivatives were also found to be cytotoxic with EC50 values of 1.207 ± 0.58 and 24.08 ±13.14 nM, respectively. 11-(4-Chlorophenyl-1,8,10, 12-tetraazatricyclo[7.4.0.02,7]trideca-2(7),3,5,9,11-pentaene-13-thione (12), 11-(4-methoxyphenyl)-1,8,10,12-tetraazatricyclo[7.4.0.02,7]trideca-2(7),3,9,1-pentaene-13-thione (14), and 11-phenyl-1,8,10,12-tetraazatricyclo[7.4.0.02,7]trideca-2(7),3,5,9,11-pentaene-13-thione (20), were found to be cytotoxic giving EC50 values of 0.152 ± 0.051, 37.96 ± 21.87 and 5.28 ± 2.95 μM, respectively. In the enzyme inhibition studies compound 49 gave a percentage inhibition of 97.03 ± 10.61% at 100 μM, but the fact that it is cytoxic might make it less useful, whilst compounds 19 and 16 had a percentage inhibition of 59.57 ± 13.59% (4-nitro derivative) and 79.97 ± 11.97% (3-nitro derivative) respectively at 100 μM of inhibitor and 20 μM of enzyme (HIV-1 protease). The results suggests that the presence of the nitro group at position 3 (16) and 4 (19) leads to an increase in activity against HIV-1 protease.
- Full Text:
- Date Issued: 2016
- Authors: Odame, Felix
- Date: 2016
- Subjects: HIV (Viruses) -- Enzymes Enzyme inhibitors -- Research , Pharmaceutical chemistry Biochemistry
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/33228 , vital:32585
- Description: The synthesis and evaluation of benzoyl isothiocyanate derivatives as potential HIV-1 protease inhibitors is presented. The ligands were first designed to fit the protease active site using Autodock 4.2. The design was based on the deNOVO method of drug design in which the active site coordinates from the crystal structure of protease bound to ritonavir was used. An attempt to access the scaffolds designed initially led to the formation of 2,2,4-trimethyl 2,3-dihydro-1H-1,5-benzodiazepin-5-ium isophthalate and 2-2-(3-methylphenyl-1Hbenzimidazole which could not be converted to the desired intermediate. A further attempt led to formation of amino acid and amino acid ester derivatives of benzoyl isothiocyanates which have been fully characterized and the reasons why the desired intermediates were not readily accessible explained. Scaffolds based on the benzoyl isothiocyanate derivatives of structurally diverse diamines were then screened. Sixty compounds have been synthesized and fully characterized using elemental analysis, spectroscopy, GC-MS and twenty-six crystal structures have been discussed. The DFT transition state studies of 11-phenyl- 1,8,10,12-tetraazatricyclo[7.4.0.02,7]trideca-2(7),3,5,9,11-pentaene-13-thione (20), N-(1Hbenzimidazol-2-yl)benzamide (21), 3-(1,3-benzothiazol-2-yl)-1-(benzoyl)thiourea (23), and N-[(9E)-8,10,17-triazatetracyclo[8.7.0.02,7.011,16]heptadeca-1(17),2,4,6,11(16),12,14-heptaen-9-ylidene] benzamide (39), have been carried out and their detailed density functional theory reaction mechanism have be computed. The Bernly algorithm was used in the determination of saddle points (transtions states), and the intrinsic reaction coordinates leading to the determination of intermediates were traced and optimized to a global minimum or in some cases a local minimum was obtained. The cell viability tests of diamine derivatives which was done by exposing white blood cells to the compounds (inhibitors) at 37 °C and a pH of 7.4 showed that 1-(4-bromobenzoyl)-3-[2- ({[(4-bromophenyl)formamido]methanethioyl}amino)phenyl]thiourea (46), 1-(3-chloro benzoyl)-3-[2-({[(3-chlorophenyl)formamido]methanethioyl}amino)phenyl]thiourea (48), 1- (3-bromobenzoyl)-3-[2-({[(3-bromophenyl)formamido]methanethioyl}amino)phenyl] thiourea (49) and 3-benzoyl-1-(4-{[(phenylformamido)methanethioyl]amino}butyl)thiourea (54), in that group of compounds were cytotoxic with EC50 values of 17.04 ± 9.75 μM, 69.20± 38.16 μM, 35.90 ± 20.55 μM and 68.37 ± 26.45 μM, respectively. 4-Bromo-N-[(9E)-8,10,17-triazatetracyclo[8.7.0.02,7.011,16]heptadeca-1(17),2,4,6,11(16),12,14-heptaen-9-ylidene] benzamide (32), 4-methoxy-N-[(9E)-8,10,17-triazatetracyclo[8.7.0.02,7.011,16]heptadeca-1(17),2,4,6,11(16),12,14-heptaen-9-ylidene]benzamide (33) and 3-chloro-N-[(9E)-8,10,17-triazatetracyclo[8.7.0.02,7.011,16]heptadeca-1(17),2,4,6,11(16),12,14-heptaen-9-ylidene] benzamide (37) were also cytotoxic giving EC50 values of 45.47 ± 21.92, 45.09 ±13.79 and 74.94 ± 13.17 μM, respectively. 3-(1,3-Benzothiazol-2-yl)-1-(3-bromobenzoyl)thiourea (31) and 3-(1,3-benzothiazoyl-2-yl)-1-(4-nitrobenzoyl)thiourea (30) derivatives were also found to be cytotoxic with EC50 values of 1.207 ± 0.58 and 24.08 ±13.14 nM, respectively. 11-(4-Chlorophenyl-1,8,10, 12-tetraazatricyclo[7.4.0.02,7]trideca-2(7),3,5,9,11-pentaene-13-thione (12), 11-(4-methoxyphenyl)-1,8,10,12-tetraazatricyclo[7.4.0.02,7]trideca-2(7),3,9,1-pentaene-13-thione (14), and 11-phenyl-1,8,10,12-tetraazatricyclo[7.4.0.02,7]trideca-2(7),3,5,9,11-pentaene-13-thione (20), were found to be cytotoxic giving EC50 values of 0.152 ± 0.051, 37.96 ± 21.87 and 5.28 ± 2.95 μM, respectively. In the enzyme inhibition studies compound 49 gave a percentage inhibition of 97.03 ± 10.61% at 100 μM, but the fact that it is cytoxic might make it less useful, whilst compounds 19 and 16 had a percentage inhibition of 59.57 ± 13.59% (4-nitro derivative) and 79.97 ± 11.97% (3-nitro derivative) respectively at 100 μM of inhibitor and 20 μM of enzyme (HIV-1 protease). The results suggests that the presence of the nitro group at position 3 (16) and 4 (19) leads to an increase in activity against HIV-1 protease.
- Full Text:
- Date Issued: 2016
Biocomposites from polyfurfuryl alcohol reinforced with microfibres and nanocellulose from flax fibres and maize stalks
- Mtibe, Asanda, Linganiso, Linda
- Authors: Mtibe, Asanda , Linganiso, Linda
- Date: 2016
- Subjects: Textile chemistry Textile chemicals Cellulose -- Chemistry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/12175 , vital:27041
- Description: This study is aimed at extracting cellulose and nanocelluloses (cellulose nanocrystals (CNCs) and cellulose nanofibres (CNFs)) from maize stalks and flax fibres. Both flax fibres and maize stalks are composed of cellulose, lignin, hemicellulose and extractives. The extraction of cellulose involves the removal of lignin, hemicellulose and extractives. The presence of these components in plant fibres hinders the extraction of cellulose and nanocelluloses. Prior to extraction of cellulose, the different concentrations (1 wt.%, 1.5 wt.% and 2 wt.%) of NaOH were optimised. However, chemical compositions and XRD results revealed that the treatment of flax fibres with 1.5 wt.% sodium hydroxide (NaOH) gives optimum results and this concentration was further selected for the extraction of cellulose. Cellulose was extracted by chemical treatments (sodium hydroxide (NaOH), sodium chlorite (NaClO2) and potassium hydroxide (KOH)) and a combination of chemical treatments and mechanical process (supermass colloider). The materials obtained after each treatment stage during the extraction process were characterised by different characterisation techniques such as Fourier transform infrared (FTIR) spectroscopy, environmental scanning electron microscopy (ESEM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The results from the aforementioned characterisation techniques confirmed that cellulose was successfully extracted from flax fibres and maize stalks. Cellulose nanocrystals (CNCs) were extracted by sulphuric acid hydrolysis accompanied with ultra-sonication from cellulose obtained from flax fibres and maize stalks. The extracted CNCs were rod-like material with diameters and lengths in nanoscale and microscale, respectively. On the other hand, cellulose nanofibres (CNFs) were extracted by mechanical process (supermass colloider). The extracted CNFs were web-like material with diameters and lengths in nanoscale and microscale, respectively. The dimensions of nanocelluloses were measured by atomic force microscopy (AFM). Their dispersion was investigated by light polarised microscopy. The extracted nanocelluloses and cellulose were used to produce nanopapers and micropaper. Nanopapers mimic the traditional paper, the only difference of the nanopapers is that they are produced from high aspect ratio nanomaterials. Both nanopapers and micropapers were prepared by solvent evaporating method. Their thermal, optical and mechanical properties were investigated and compared. The mechanical and thermal properties of nanopapers produced from CNFs were better than those produced from CNCs and micropapers. On the other hand, nanopapers produced from CNCs were more transparent in comparison to nanopapers produced from CNFs and micropapers. Cellulosic fibres have attracted a considerable attention in composite materials due to their high tensile strength and tensile modulus. This study is focused on the development of biocomposites of polyfurfuryl alcohol (PFA) by in-situ polymerisation in the presence of acid catalyst (p-toluene sulphonic acid). Biocomposites were produced by reinforcing PFA with flax fibres (untreated and treated), nanoparticles and CNCs. The biocomposites reinforced with CNCs and flax fibres showed an improvement in mechanical, thermal and thermo-mechanical properties. On the other hand, biocomposites reinforced with nanoparticles obtained from treated maize stalks showed an improvement in mechanical and thermal properties while biocomposites reinforced with nanoparticles obtained from untreated maize stalks showed lower mechanical properties and decreased thermal stability.
- Full Text:
- Date Issued: 2016
- Authors: Mtibe, Asanda , Linganiso, Linda
- Date: 2016
- Subjects: Textile chemistry Textile chemicals Cellulose -- Chemistry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/12175 , vital:27041
- Description: This study is aimed at extracting cellulose and nanocelluloses (cellulose nanocrystals (CNCs) and cellulose nanofibres (CNFs)) from maize stalks and flax fibres. Both flax fibres and maize stalks are composed of cellulose, lignin, hemicellulose and extractives. The extraction of cellulose involves the removal of lignin, hemicellulose and extractives. The presence of these components in plant fibres hinders the extraction of cellulose and nanocelluloses. Prior to extraction of cellulose, the different concentrations (1 wt.%, 1.5 wt.% and 2 wt.%) of NaOH were optimised. However, chemical compositions and XRD results revealed that the treatment of flax fibres with 1.5 wt.% sodium hydroxide (NaOH) gives optimum results and this concentration was further selected for the extraction of cellulose. Cellulose was extracted by chemical treatments (sodium hydroxide (NaOH), sodium chlorite (NaClO2) and potassium hydroxide (KOH)) and a combination of chemical treatments and mechanical process (supermass colloider). The materials obtained after each treatment stage during the extraction process were characterised by different characterisation techniques such as Fourier transform infrared (FTIR) spectroscopy, environmental scanning electron microscopy (ESEM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The results from the aforementioned characterisation techniques confirmed that cellulose was successfully extracted from flax fibres and maize stalks. Cellulose nanocrystals (CNCs) were extracted by sulphuric acid hydrolysis accompanied with ultra-sonication from cellulose obtained from flax fibres and maize stalks. The extracted CNCs were rod-like material with diameters and lengths in nanoscale and microscale, respectively. On the other hand, cellulose nanofibres (CNFs) were extracted by mechanical process (supermass colloider). The extracted CNFs were web-like material with diameters and lengths in nanoscale and microscale, respectively. The dimensions of nanocelluloses were measured by atomic force microscopy (AFM). Their dispersion was investigated by light polarised microscopy. The extracted nanocelluloses and cellulose were used to produce nanopapers and micropaper. Nanopapers mimic the traditional paper, the only difference of the nanopapers is that they are produced from high aspect ratio nanomaterials. Both nanopapers and micropapers were prepared by solvent evaporating method. Their thermal, optical and mechanical properties were investigated and compared. The mechanical and thermal properties of nanopapers produced from CNFs were better than those produced from CNCs and micropapers. On the other hand, nanopapers produced from CNCs were more transparent in comparison to nanopapers produced from CNFs and micropapers. Cellulosic fibres have attracted a considerable attention in composite materials due to their high tensile strength and tensile modulus. This study is focused on the development of biocomposites of polyfurfuryl alcohol (PFA) by in-situ polymerisation in the presence of acid catalyst (p-toluene sulphonic acid). Biocomposites were produced by reinforcing PFA with flax fibres (untreated and treated), nanoparticles and CNCs. The biocomposites reinforced with CNCs and flax fibres showed an improvement in mechanical, thermal and thermo-mechanical properties. On the other hand, biocomposites reinforced with nanoparticles obtained from treated maize stalks showed an improvement in mechanical and thermal properties while biocomposites reinforced with nanoparticles obtained from untreated maize stalks showed lower mechanical properties and decreased thermal stability.
- Full Text:
- Date Issued: 2016
Business ethics in Ugandan small and medium-sized enterprises
- Authors: Mayanja, Jamiah
- Date: 2016
- Subjects: Business ethics -- Uganda , Small business -- Uganda
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/8521 , vital:26400
- Description: SMEs have been acknowledged by governments globally as a prime source of economic growth and development. In Africa there has been a noticeable increase in the number of SME establishments. In Uganda, SMEs are the most popular business choice and play a major role in the national economy. Although SMEs significant economic contributions are generally acknowledged, being ethical and successful has become a challenge, as many SMEs in Uganda have not fully adopted and integrated ethics into their business strategies. Understanding the reasons for the increased unethical behaviour in SMEs is central to their continued business success. The primary objective of the study was to investigate the factors that influence ethical business conduct in Ugandan SMEs. From a comprehensive literature review, three main independent variables (staff-, business- and external environment factors) were identified as variables influencing ethical business conduct (dependent variable) of SMEs. A hypothetical model was developed to determine whether the independent variables have an influence on the dependent variable. Twelve hypotheses were formulated to test the relationships between three staff factors, five business factors, four external environment factors and ethical business conduct. The study sought the perceptions of SME owners or managers in the Kampala District and utilised the quantitative research paradigm. A survey was conducted with the aid of a structured self-administered questionnaire distributed by three fieldworkers. A combination of convenience and snowball sampling was utilised. The final sample comprised 384 respondents. The validity of the measuring instrument was ascertained by using exploratory factor analysis. The Cronbach‟s alpha values for reliability were calculated for each of the factors identified during the exploratory factor analysis. A total of ten valid and reliable factors were retained. Pearson product-moment correlation and multiple regression analysis were used to test the correlation and statistical significance of the relationships hypothesised between the various independent and dependent variables. One statistically significant relationship was found between the staff factors (employee attitude) and ethical business conduct. Two statistically significant relationships were found between the business factors (knowledge acquisition and management practices) and ethical business conduct. Three statistically significant relationships were found between the external environment factors (legal requirements, industry norm and media power) and ethical business conduct. External environmental factors seem to have a greater influence on SME ethical business conduct in Uganda. Multivariate Analysis of Variance (MANOVA) was used to identify if significant relationships exist between the eight demographic variables and seven reliable and valid independent variables. Furthermore, post-hoc Scheffé tests identified where the significant differences occurred between the different categories. Cohen‟s d-values were calculated in order to assess the practical significance of the mean scores. A total of twelve practical significant relationships were identified. SME owners or managers should consider employing staff with the right attitude to uphold sound ethical business values. They should implement ethical management practices to promote ethical business conduct amongst employees and ensure that employees are made aware of what is regarded as acceptable ethical business behaviour. SME owners or managers should adhere to legal requirements and industry norms to be known as businesses exhibiting ethical behaviour and utilise media to instil and guide ethical values in employees. Lastly, they must pay attention to the role that demographical variables such as: gender, level of education, current employment status, number of years in business and number of employees, play in behaving ethically in business.
- Full Text:
- Date Issued: 2016
- Authors: Mayanja, Jamiah
- Date: 2016
- Subjects: Business ethics -- Uganda , Small business -- Uganda
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/8521 , vital:26400
- Description: SMEs have been acknowledged by governments globally as a prime source of economic growth and development. In Africa there has been a noticeable increase in the number of SME establishments. In Uganda, SMEs are the most popular business choice and play a major role in the national economy. Although SMEs significant economic contributions are generally acknowledged, being ethical and successful has become a challenge, as many SMEs in Uganda have not fully adopted and integrated ethics into their business strategies. Understanding the reasons for the increased unethical behaviour in SMEs is central to their continued business success. The primary objective of the study was to investigate the factors that influence ethical business conduct in Ugandan SMEs. From a comprehensive literature review, three main independent variables (staff-, business- and external environment factors) were identified as variables influencing ethical business conduct (dependent variable) of SMEs. A hypothetical model was developed to determine whether the independent variables have an influence on the dependent variable. Twelve hypotheses were formulated to test the relationships between three staff factors, five business factors, four external environment factors and ethical business conduct. The study sought the perceptions of SME owners or managers in the Kampala District and utilised the quantitative research paradigm. A survey was conducted with the aid of a structured self-administered questionnaire distributed by three fieldworkers. A combination of convenience and snowball sampling was utilised. The final sample comprised 384 respondents. The validity of the measuring instrument was ascertained by using exploratory factor analysis. The Cronbach‟s alpha values for reliability were calculated for each of the factors identified during the exploratory factor analysis. A total of ten valid and reliable factors were retained. Pearson product-moment correlation and multiple regression analysis were used to test the correlation and statistical significance of the relationships hypothesised between the various independent and dependent variables. One statistically significant relationship was found between the staff factors (employee attitude) and ethical business conduct. Two statistically significant relationships were found between the business factors (knowledge acquisition and management practices) and ethical business conduct. Three statistically significant relationships were found between the external environment factors (legal requirements, industry norm and media power) and ethical business conduct. External environmental factors seem to have a greater influence on SME ethical business conduct in Uganda. Multivariate Analysis of Variance (MANOVA) was used to identify if significant relationships exist between the eight demographic variables and seven reliable and valid independent variables. Furthermore, post-hoc Scheffé tests identified where the significant differences occurred between the different categories. Cohen‟s d-values were calculated in order to assess the practical significance of the mean scores. A total of twelve practical significant relationships were identified. SME owners or managers should consider employing staff with the right attitude to uphold sound ethical business values. They should implement ethical management practices to promote ethical business conduct amongst employees and ensure that employees are made aware of what is regarded as acceptable ethical business behaviour. SME owners or managers should adhere to legal requirements and industry norms to be known as businesses exhibiting ethical behaviour and utilise media to instil and guide ethical values in employees. Lastly, they must pay attention to the role that demographical variables such as: gender, level of education, current employment status, number of years in business and number of employees, play in behaving ethically in business.
- Full Text:
- Date Issued: 2016
Causes of staff turnover in selected departments: province of the Eastern Cape
- Authors: Khelekethe, Eric Phathisile
- Date: 2016
- Subjects: Labor turnover -- South Africa -- Eastern Cape , Employee retention -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/8836 , vital:26434
- Description: This research focused on the impact of staff turnover in selected departments of the Province of the Eastern Cape Province. High staff turnover rate may jeopardise efforts to attain organisational objectives. In addition, `when an organisation loses a critical employee, there is a negative impact, on innovation; consistency in providing service to guests may be jeopardised, and major delays in the delivery of services to customers may occur. The research design used in this study contained elements of both the quantitative and qualitative approaches, which allowed the researcher to use structured questionnaires in data collection, on which space was provided for comments. This study was influenced and shaped by the concerns raised by a number of General Managers in the course of various provincial meetings. The main purpose of this research was to identify retention strategies that could be used by selected departments to reduce the turnover of their talented staff. The research also investigated methods to retain knowledge within departments that could possibly be lost due to a high turnover rate among talented staff. The first step used to resolve the issues discussed above was to conduct a full literature study. The literature study sought to reveal what characteristics were required in the departments that ensured that staff would be happy in those departments and remain there for a long time. The literature study also covered what knowledge management methods could be used in managing valuable knowledge. Secondly, the views of current staff and management of the selected departments on staff and knowledge management strategies were solicited in an empirical study, which involved the completion of structured questionnaires. It is the researcher’s aim that this study will, firstly, contribute to the existing body of knowledge of staff turnover and that the Provincial Departments will take into cognisance the problems that lead to employee turnover. Secondly, that it will contribute to an improvement in employee working conditions in various Provincial Government departments.
- Full Text:
- Date Issued: 2016
- Authors: Khelekethe, Eric Phathisile
- Date: 2016
- Subjects: Labor turnover -- South Africa -- Eastern Cape , Employee retention -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/8836 , vital:26434
- Description: This research focused on the impact of staff turnover in selected departments of the Province of the Eastern Cape Province. High staff turnover rate may jeopardise efforts to attain organisational objectives. In addition, `when an organisation loses a critical employee, there is a negative impact, on innovation; consistency in providing service to guests may be jeopardised, and major delays in the delivery of services to customers may occur. The research design used in this study contained elements of both the quantitative and qualitative approaches, which allowed the researcher to use structured questionnaires in data collection, on which space was provided for comments. This study was influenced and shaped by the concerns raised by a number of General Managers in the course of various provincial meetings. The main purpose of this research was to identify retention strategies that could be used by selected departments to reduce the turnover of their talented staff. The research also investigated methods to retain knowledge within departments that could possibly be lost due to a high turnover rate among talented staff. The first step used to resolve the issues discussed above was to conduct a full literature study. The literature study sought to reveal what characteristics were required in the departments that ensured that staff would be happy in those departments and remain there for a long time. The literature study also covered what knowledge management methods could be used in managing valuable knowledge. Secondly, the views of current staff and management of the selected departments on staff and knowledge management strategies were solicited in an empirical study, which involved the completion of structured questionnaires. It is the researcher’s aim that this study will, firstly, contribute to the existing body of knowledge of staff turnover and that the Provincial Departments will take into cognisance the problems that lead to employee turnover. Secondly, that it will contribute to an improvement in employee working conditions in various Provincial Government departments.
- Full Text:
- Date Issued: 2016
Conflict management in Kenyan electoral conflict: 2002-2012
- Muhindi, Solomon Peter Kavai
- Authors: Muhindi, Solomon Peter Kavai
- Date: 2016
- Subjects: Conflict management -- Africa Elections -- Kenya Kenya -- Politics and government
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/12286 , vital:27051
- Description: In the recent years, majority of African countries have been faced by conflicts during election periods. Some of the electoral related conflicts escalated into violence, and they have been transformed or managed. While other electoral related conflicts have just been prevented during the election periods but remain latent conflicts that would escalate triggered by future elections. This study focuses specifically on electoral conflicts in Kenya and its conflict management perspective from 2002-2013. To transform and manage the conflict, peacebuilding initiatives have been integrated in the study. The prime actors in Kenya electoral conflict includes the; the ruling party coalition, the leading opposition coalition and ethnic groupings affiliated to the ruling party and opposition. Other peripheral actors include: the Independent, Electoral and Boundary Commission (IEBC), the International Criminal Court (ICC) and the judiciary. Triangulation (the combination of two or more methods of collecting and analysing data) has been adopted both in data collection and analysis. Focus group interviews, selected individual interviews, and literature reviews were used to collect data, while research findings were analysed systematically using the constructivist grounded theory. Moreover, the liberal peace theory, Institutionalisation before Liberalisation (IBL) and findings from other researchers like (Elder, Stigant and Claes 2014:1-20), and the Afrobarometer research findings (Kivuva 2015) have been used to authenticate the research findings. Research findings indicates that claims of election rigging, numerous institutional failures, negative ethnicity and economic disparity, among other factors heighten the fear and anxiety that escalates during elections. Towards achieving peacebuilding and sustainable peace, the following reforms were undertaken: constitutional changes and reviews, electoral body reform, judicial reform, pursuit of transitional justice, extensive range of local initiatives reforms and police reforms. However, findings in the study also reveal that despite the latter reforms, peacebuilding measures have been short-term, temporal, and not fully successful, leaving behind a latent conflict that could be triggered again with future electoral conflicts. Besides that, negotiation, dialogue and mediation played a role in restoring trust and confidence in the democratic structures after escalated elections. We also recommend that multi-ethnic composition for electoral coalitions should also be adopted as a means to mitigate ethnic triggered conflicts.
- Full Text:
- Date Issued: 2016
- Authors: Muhindi, Solomon Peter Kavai
- Date: 2016
- Subjects: Conflict management -- Africa Elections -- Kenya Kenya -- Politics and government
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/12286 , vital:27051
- Description: In the recent years, majority of African countries have been faced by conflicts during election periods. Some of the electoral related conflicts escalated into violence, and they have been transformed or managed. While other electoral related conflicts have just been prevented during the election periods but remain latent conflicts that would escalate triggered by future elections. This study focuses specifically on electoral conflicts in Kenya and its conflict management perspective from 2002-2013. To transform and manage the conflict, peacebuilding initiatives have been integrated in the study. The prime actors in Kenya electoral conflict includes the; the ruling party coalition, the leading opposition coalition and ethnic groupings affiliated to the ruling party and opposition. Other peripheral actors include: the Independent, Electoral and Boundary Commission (IEBC), the International Criminal Court (ICC) and the judiciary. Triangulation (the combination of two or more methods of collecting and analysing data) has been adopted both in data collection and analysis. Focus group interviews, selected individual interviews, and literature reviews were used to collect data, while research findings were analysed systematically using the constructivist grounded theory. Moreover, the liberal peace theory, Institutionalisation before Liberalisation (IBL) and findings from other researchers like (Elder, Stigant and Claes 2014:1-20), and the Afrobarometer research findings (Kivuva 2015) have been used to authenticate the research findings. Research findings indicates that claims of election rigging, numerous institutional failures, negative ethnicity and economic disparity, among other factors heighten the fear and anxiety that escalates during elections. Towards achieving peacebuilding and sustainable peace, the following reforms were undertaken: constitutional changes and reviews, electoral body reform, judicial reform, pursuit of transitional justice, extensive range of local initiatives reforms and police reforms. However, findings in the study also reveal that despite the latter reforms, peacebuilding measures have been short-term, temporal, and not fully successful, leaving behind a latent conflict that could be triggered again with future electoral conflicts. Besides that, negotiation, dialogue and mediation played a role in restoring trust and confidence in the democratic structures after escalated elections. We also recommend that multi-ethnic composition for electoral coalitions should also be adopted as a means to mitigate ethnic triggered conflicts.
- Full Text:
- Date Issued: 2016
Continuous flow synthesis of silicon compounds as feedstock for solar-grade silicon production
- Authors: Chigondo, Fidelis
- Date: 2016
- Subjects: Silicon -- Synthesis , Homogeneous catalysis
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: http://hdl.handle.net/10948/4529 , vital:20613
- Description: This thesis describes the key steps in the production of high purity (solar-grade) silicon from metallurgical-grade silicon for use in the production of photovoltaic cells as alternative renewable, environmentally benign and cheap energy source. The initial part of the project involves the development and optimization of a small chemical production platform system capable of producing alkoxysilanes from metallurgical-grade silicon as green precursors to solar-grade silicon production. Specifically, the main aim of the study was to synthesize trialkoxysilanes in continuous flow mode, although the synthesis on monosilane was also done in batch mode. The alkoxylation reaction was carried out in a traditional slurry phase batch reactor, packed bed flow tubular reactor and also attempted in a continuous flow falling film tubular reactor. The effect of key parameters which affect the silicon conversion and selectivity for the desired trialkoxysilane were investigated and optimized using ethanol as a reagent model. The synthesis was then extended to the other alcohols namely methanol, n-propanol and n-butanol. Copper catalysts which were tested in the alkoxylation reaction included: CuCl, Cu(OH)2, CuO and CuSO4. CuCl and Cu(OH)2 showed comparable activity in the batch mode but the former was more efficient in the packed bed flow tubular reactor. Cu(OH)2 could be used as a non-halide catalyst but its activity is limited to short reaction cycles (<10 h). The uncatalysed reaction resulted in negligible reaction rates in both types of reactors. High temperature catalyst pre-heating (>500 oC) resulted in a lower rate of reaction and selectivity than when slightly lower temperatures are used (<350 oC) in both reactors, although much difference was noticed in the packed bed flow tubular reactor. Synthesis in the batch reactor needed longer silicon-catalyst activation time, higher pre-heating temperature and higher catalyst amounts as compare to the packed bed flow tubular reactor. Reaction temperature and alcohol flow rate influenced the reaction in both methods. The optimum reaction temperature range and alcohol flow rate was comparable in both reactors (230 to 240 oC) and 0.1mL/min respectively. The effect of alcohol R-group (C1 to C4) on the reaction revealed that conversion and selectivity generally decrease with an increase in carbon chain length in both methods. Ethanol showed highest selectivity (>95% in batch and >97% in flow) and conversion (about 88% in batch and about 64% in flow) as compared to all other alcohols studied showing that it could be the most efficient alkoxylation alcohol for this reaction. Overally, the packed bed flow tubular reactor resulted in higher selectivity to trialkoxysilanes than the batch system. Performing the reaction under pressure resulted in increased conversion but selectivity to the desire trialkoxysilane diminished. Synthesis in a continuous flow falling film tubular reactor was not successful as it resulted in very poor conversion and selectivity. Monosilane was successfully synthesized from the disproportionation of triethoxysilane using homogeneous and heterogeneous catalysts in batch mode. The results obtained from homogeneous catalysis showed that the reaction can be conducted at room temperature. The heterogeneous catalysis method resulted in slow conversion at room temperature but mild heating up to 55 oC greatly improved the reaction. Conducting the reaction under neat conditions produced comparable results to reactions which were carried out using solvents. The disproportionation reaction was best described by the first order kinetic model. The results obtained in this research indicate that the packed bed flow tubular reactor can be utilized with future modifications for continuous flow synthesis of alkoxysilanes as feedstock for the solar-grade silicon production.
- Full Text:
- Date Issued: 2016
- Authors: Chigondo, Fidelis
- Date: 2016
- Subjects: Silicon -- Synthesis , Homogeneous catalysis
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: http://hdl.handle.net/10948/4529 , vital:20613
- Description: This thesis describes the key steps in the production of high purity (solar-grade) silicon from metallurgical-grade silicon for use in the production of photovoltaic cells as alternative renewable, environmentally benign and cheap energy source. The initial part of the project involves the development and optimization of a small chemical production platform system capable of producing alkoxysilanes from metallurgical-grade silicon as green precursors to solar-grade silicon production. Specifically, the main aim of the study was to synthesize trialkoxysilanes in continuous flow mode, although the synthesis on monosilane was also done in batch mode. The alkoxylation reaction was carried out in a traditional slurry phase batch reactor, packed bed flow tubular reactor and also attempted in a continuous flow falling film tubular reactor. The effect of key parameters which affect the silicon conversion and selectivity for the desired trialkoxysilane were investigated and optimized using ethanol as a reagent model. The synthesis was then extended to the other alcohols namely methanol, n-propanol and n-butanol. Copper catalysts which were tested in the alkoxylation reaction included: CuCl, Cu(OH)2, CuO and CuSO4. CuCl and Cu(OH)2 showed comparable activity in the batch mode but the former was more efficient in the packed bed flow tubular reactor. Cu(OH)2 could be used as a non-halide catalyst but its activity is limited to short reaction cycles (<10 h). The uncatalysed reaction resulted in negligible reaction rates in both types of reactors. High temperature catalyst pre-heating (>500 oC) resulted in a lower rate of reaction and selectivity than when slightly lower temperatures are used (<350 oC) in both reactors, although much difference was noticed in the packed bed flow tubular reactor. Synthesis in the batch reactor needed longer silicon-catalyst activation time, higher pre-heating temperature and higher catalyst amounts as compare to the packed bed flow tubular reactor. Reaction temperature and alcohol flow rate influenced the reaction in both methods. The optimum reaction temperature range and alcohol flow rate was comparable in both reactors (230 to 240 oC) and 0.1mL/min respectively. The effect of alcohol R-group (C1 to C4) on the reaction revealed that conversion and selectivity generally decrease with an increase in carbon chain length in both methods. Ethanol showed highest selectivity (>95% in batch and >97% in flow) and conversion (about 88% in batch and about 64% in flow) as compared to all other alcohols studied showing that it could be the most efficient alkoxylation alcohol for this reaction. Overally, the packed bed flow tubular reactor resulted in higher selectivity to trialkoxysilanes than the batch system. Performing the reaction under pressure resulted in increased conversion but selectivity to the desire trialkoxysilane diminished. Synthesis in a continuous flow falling film tubular reactor was not successful as it resulted in very poor conversion and selectivity. Monosilane was successfully synthesized from the disproportionation of triethoxysilane using homogeneous and heterogeneous catalysts in batch mode. The results obtained from homogeneous catalysis showed that the reaction can be conducted at room temperature. The heterogeneous catalysis method resulted in slow conversion at room temperature but mild heating up to 55 oC greatly improved the reaction. Conducting the reaction under neat conditions produced comparable results to reactions which were carried out using solvents. The disproportionation reaction was best described by the first order kinetic model. The results obtained in this research indicate that the packed bed flow tubular reactor can be utilized with future modifications for continuous flow synthesis of alkoxysilanes as feedstock for the solar-grade silicon production.
- Full Text:
- Date Issued: 2016
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
Development of a small production platform for citronellal processing
- Mafu, Lubabalo Rowan, Zeelie, Ben
- Authors: Mafu, Lubabalo Rowan , Zeelie, Ben
- Date: 2016
- Subjects: Organic compounds -- Synthesis , Plasticizers
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/8488 , vital:26370
- Description: The aim of the project was to develop a small production platform for citronellal processing. The objective of the study was to develop a single continuous flow reactor system for the synthesis of novel derivatives of citronellal and isopulegol. The first step was to develop a continuous flow reactor system for the isopulegol synthesis. The stainless steel tubular fixed-bed reactor equipped with a reaction column (I.D: 9.53 mm and length: 120 mm) was used for the study. The reactor column was packed with H-ZMS-5 zeolite extrusion catalyst. The solvent-free cyclisation reaction of citronellal was investigated and at optimum conditions, 100% of citronellal conversion and almost 100% selectivity towards isopulegol was achieved. A good catalytic performance was observed from the H-ZSM-5 catalyst and proved to be stable for a prolonged reaction time. The second reaction step was to develop a continuous flow reactor system for the synthesis of isopulegyl-ether derivatives. A UniQsis FlowSyn reactor system equipped with a stainless steel reactor column was used for the study. The reactor column was packed with amberlyst-15 dry catalyst. Wherein, n-propanol was employed as a model etherifying agent and as a reaction solvent. At optimum reaction condition, only 30% selectivity of isopulegyl propoxy-ether was achieved. The reaction was found to depend highly on temperature and residence time. The increase of these parameters was found to increase the side reactions and reduced the selectivity of the desired product. Other heterogeneous catalysts such as H-beta zeolite, aluminium pillared clay, Aluminium oxide and H-ZSM-5 were also evaluated in the reaction. Among these catalysts, a catalytic activity was observed with H-beta zeolite (19%) and aluminium pillared clay (5%). Based on these results, none of the evaluated catalysts provided the desired selectivity (greater than 70%) towards the isopulegyl propoxy-ether, therefore the process was not investigated further. In light of this, the isopulegol etherification synthetic route was terminated. Consequently, another analogue of citronellal was used as an alternative intermediate in place of isopulegol, namely para-menthane-3,8-diol (PMD). The initial studies for the synthesis of the novel PMD di-esters from isopulegol were performed in the batch-scale reactor. In a solvent-free reaction, acetic anhydride was initially used as a model acetylating agent. The reaction was performed using polymer-bound scandium triflate (PS-Sc(OTf)3) catalyst. The effect of reaction parameters such as temperature, molar ratio, and reaction time were studied towards the PMD conversion and di-esters selectivity. At optimum reaction conditions, PMD conversion of 70% and di-acetate selectivity of 67% were observed. The reaction was found to follow the zeroth-order kinetics with respect to PMD conversion and obeyed the Arrhenius equation. Other types of di-ester derivatives were synthesized from PMD by varying the carbon chain length of the acetylating agent. The prepared compounds were separated from the product mixtures by vacuum distillation, purified on a column chromatography and characterised by FT-IR, GC-MS, and 1H-NMR, 13C-NMR. The developed methodology was optimised in flow by using an ArrheniumOne microwave-assisted continuous-flow fixed-bed reactor system. A detailed experimental design was used to carry-out the reactions. The reaction parameters such as temperature and flow-rate were studied towards the PMD conversion and di-ester selectivity. From the experimental design analysis, the di-ester selectivity was found to depend highly on the residence time (flow-rate) and significantly on temperature. The PMD conversion and di-ester selectivity were found to increase with decrease in the flow-rate. The conversion and selectivity achieved in the continuous flow process were significantly higher than the achieved in the batch-scale process with respect to the residence time.
- Full Text:
- Date Issued: 2016
- Authors: Mafu, Lubabalo Rowan , Zeelie, Ben
- Date: 2016
- Subjects: Organic compounds -- Synthesis , Plasticizers
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/8488 , vital:26370
- Description: The aim of the project was to develop a small production platform for citronellal processing. The objective of the study was to develop a single continuous flow reactor system for the synthesis of novel derivatives of citronellal and isopulegol. The first step was to develop a continuous flow reactor system for the isopulegol synthesis. The stainless steel tubular fixed-bed reactor equipped with a reaction column (I.D: 9.53 mm and length: 120 mm) was used for the study. The reactor column was packed with H-ZMS-5 zeolite extrusion catalyst. The solvent-free cyclisation reaction of citronellal was investigated and at optimum conditions, 100% of citronellal conversion and almost 100% selectivity towards isopulegol was achieved. A good catalytic performance was observed from the H-ZSM-5 catalyst and proved to be stable for a prolonged reaction time. The second reaction step was to develop a continuous flow reactor system for the synthesis of isopulegyl-ether derivatives. A UniQsis FlowSyn reactor system equipped with a stainless steel reactor column was used for the study. The reactor column was packed with amberlyst-15 dry catalyst. Wherein, n-propanol was employed as a model etherifying agent and as a reaction solvent. At optimum reaction condition, only 30% selectivity of isopulegyl propoxy-ether was achieved. The reaction was found to depend highly on temperature and residence time. The increase of these parameters was found to increase the side reactions and reduced the selectivity of the desired product. Other heterogeneous catalysts such as H-beta zeolite, aluminium pillared clay, Aluminium oxide and H-ZSM-5 were also evaluated in the reaction. Among these catalysts, a catalytic activity was observed with H-beta zeolite (19%) and aluminium pillared clay (5%). Based on these results, none of the evaluated catalysts provided the desired selectivity (greater than 70%) towards the isopulegyl propoxy-ether, therefore the process was not investigated further. In light of this, the isopulegol etherification synthetic route was terminated. Consequently, another analogue of citronellal was used as an alternative intermediate in place of isopulegol, namely para-menthane-3,8-diol (PMD). The initial studies for the synthesis of the novel PMD di-esters from isopulegol were performed in the batch-scale reactor. In a solvent-free reaction, acetic anhydride was initially used as a model acetylating agent. The reaction was performed using polymer-bound scandium triflate (PS-Sc(OTf)3) catalyst. The effect of reaction parameters such as temperature, molar ratio, and reaction time were studied towards the PMD conversion and di-esters selectivity. At optimum reaction conditions, PMD conversion of 70% and di-acetate selectivity of 67% were observed. The reaction was found to follow the zeroth-order kinetics with respect to PMD conversion and obeyed the Arrhenius equation. Other types of di-ester derivatives were synthesized from PMD by varying the carbon chain length of the acetylating agent. The prepared compounds were separated from the product mixtures by vacuum distillation, purified on a column chromatography and characterised by FT-IR, GC-MS, and 1H-NMR, 13C-NMR. The developed methodology was optimised in flow by using an ArrheniumOne microwave-assisted continuous-flow fixed-bed reactor system. A detailed experimental design was used to carry-out the reactions. The reaction parameters such as temperature and flow-rate were studied towards the PMD conversion and di-ester selectivity. From the experimental design analysis, the di-ester selectivity was found to depend highly on the residence time (flow-rate) and significantly on temperature. The PMD conversion and di-ester selectivity were found to increase with decrease in the flow-rate. The conversion and selectivity achieved in the continuous flow process were significantly higher than the achieved in the batch-scale process with respect to the residence time.
- Full Text:
- Date Issued: 2016
Digital capital: a mode of bridging capital for immigrant and refugee population
- Authors: Rosendahl, Patricia
- Date: 2016
- Subjects: Social capital (Sociology) -- United States , Immigrants -- United States
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/3645 , vital:20449
- Description: The resettlement of immigrant and refugee populations poses specific challenges to new host communities. Municipalities must find resources to assist these populations in transitioning into a new culture. Immediate needs are often adequate housing, health care, and primary schooling. While this transitioning process is still in play, the search for employment begins; often at the cost of consideration of longer-term needs, such as English or other host country language acquisition and planning for long-term career goals. Theorists in the field of social capital postulate that bonding and bridging social capital offers benefits for populations adjusting to new communities. Connections to like-minded individuals or pre-existing ethnic ties (bonding social capital) can provide support important to the well-being of individuals going through difficult social adjustments while connecting with new social groups (bridging social capital) can provide new information leading to expanding opportunities. The concept of bridging social capital for immigrant and refugee populations is the subject of this research study. It is situated within the context of our digital age in which information communication technology (ICT) is the primary mode of access to information and services. For the purpose of this thesis, the capability to exploit this mode of communication is thus identified as “digital capital.” As more and more governmental, educational, and social services are distributed within a technological environment, it is necessary to examine this mode of connection to information as a form of capital which can be viewed in a similar framework to other types of social capital. Access to technology and ICTs has been considered an integral element of the Development Goals as adopted by the United Nations for the Year 2000 Millennium Goals. Though later debates have questioned how ICTs may have benefited development goals, the pervasiveness of this form of information flow continues. Within Development Studies, Sen’s theory on the Capability Approach offers a valuable opportunity of connecting digital capital to development. Just as the Capabilities Approach accommodates the diversity of human values, characteristics, and functionings, so can digital capital provide flexibility through adaptation by the users to tailor the medium to meet specific needs. It is this freedom to adjust to individual needs and goals that allows this mode of bridging capital to hold a distinct advantage for immigrants and refugees who are searching for effective links into new social networks in the job search process. The role of the community college system has been at the forefront of providing educational training and social acclimation for this population in their quest for economic self-sufficiency in the resettlement process. A greater understanding of the role that technology plays in the success of immigrant and refugee resettlement is vitally important for the well-being of communities undergoing dynamic demographic change.
- Full Text:
- Date Issued: 2016
- Authors: Rosendahl, Patricia
- Date: 2016
- Subjects: Social capital (Sociology) -- United States , Immigrants -- United States
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/3645 , vital:20449
- Description: The resettlement of immigrant and refugee populations poses specific challenges to new host communities. Municipalities must find resources to assist these populations in transitioning into a new culture. Immediate needs are often adequate housing, health care, and primary schooling. While this transitioning process is still in play, the search for employment begins; often at the cost of consideration of longer-term needs, such as English or other host country language acquisition and planning for long-term career goals. Theorists in the field of social capital postulate that bonding and bridging social capital offers benefits for populations adjusting to new communities. Connections to like-minded individuals or pre-existing ethnic ties (bonding social capital) can provide support important to the well-being of individuals going through difficult social adjustments while connecting with new social groups (bridging social capital) can provide new information leading to expanding opportunities. The concept of bridging social capital for immigrant and refugee populations is the subject of this research study. It is situated within the context of our digital age in which information communication technology (ICT) is the primary mode of access to information and services. For the purpose of this thesis, the capability to exploit this mode of communication is thus identified as “digital capital.” As more and more governmental, educational, and social services are distributed within a technological environment, it is necessary to examine this mode of connection to information as a form of capital which can be viewed in a similar framework to other types of social capital. Access to technology and ICTs has been considered an integral element of the Development Goals as adopted by the United Nations for the Year 2000 Millennium Goals. Though later debates have questioned how ICTs may have benefited development goals, the pervasiveness of this form of information flow continues. Within Development Studies, Sen’s theory on the Capability Approach offers a valuable opportunity of connecting digital capital to development. Just as the Capabilities Approach accommodates the diversity of human values, characteristics, and functionings, so can digital capital provide flexibility through adaptation by the users to tailor the medium to meet specific needs. It is this freedom to adjust to individual needs and goals that allows this mode of bridging capital to hold a distinct advantage for immigrants and refugees who are searching for effective links into new social networks in the job search process. The role of the community college system has been at the forefront of providing educational training and social acclimation for this population in their quest for economic self-sufficiency in the resettlement process. A greater understanding of the role that technology plays in the success of immigrant and refugee resettlement is vitally important for the well-being of communities undergoing dynamic demographic change.
- Full Text:
- Date Issued: 2016