Guilt and shame as intergroup emotions applied within the South African context
- Authors: Byrnes, Janet
- Date: 2009
- Subjects: Intergroup relations , Shame , Guilt
- Language: English
- Type: Thesis , Masters , M Soc Sc (Psych)
- Identifier: vital:11607 , http://hdl.handle.net/10353/154 , Intergroup relations , Shame , Guilt
- Description: The present paper will inform about three studies that seek to make a contribution to the area of self-conscious emotions, namely guilt and shame, and their consequences for intergroup relations in a South African context. As with previous research, this research investigated whether belonging to a particular group (i.e. being a white South African) is likely to evoke feelings of collective guilt and collective shame when reminded of the atrocities of Apartheid, even though the individual members did not personally contribute to their group’s negative history. The first study aimed to investigate experimentally the effects of experienced collective ingroup guilt and shame on the desire to make reparation. The second study aimed to test the relationship between guilt/shame and reparation of white South Africans in the field. Furthermore, the second study aimed to account for the dialectical aspects of the intergroup situation by exploring guilt/shame and reparation of white South Africans as expected by young black South Africans (as members of the previously oppressed group). The third study aimed to replicate the differences between experienced guilt/shame/reparation and reported ingroup identification by white South Africans and the expected guilt/shame/reparation from white South Africans and reported ingroup identification by black South Africans as found in the study 2. In addition, the third study aimed to control the antecedents for collective guilt and for collective shame. It also explored the impact knowledge about atrocities of the ingroup (white participants) has on emotions and reparation attitudes and whether perceived status relations at present and in the future impacts the emotions as well general reparation attitudes.
- Full Text:
- Date Issued: 2009
- Authors: Byrnes, Janet
- Date: 2009
- Subjects: Intergroup relations , Shame , Guilt
- Language: English
- Type: Thesis , Masters , M Soc Sc (Psych)
- Identifier: vital:11607 , http://hdl.handle.net/10353/154 , Intergroup relations , Shame , Guilt
- Description: The present paper will inform about three studies that seek to make a contribution to the area of self-conscious emotions, namely guilt and shame, and their consequences for intergroup relations in a South African context. As with previous research, this research investigated whether belonging to a particular group (i.e. being a white South African) is likely to evoke feelings of collective guilt and collective shame when reminded of the atrocities of Apartheid, even though the individual members did not personally contribute to their group’s negative history. The first study aimed to investigate experimentally the effects of experienced collective ingroup guilt and shame on the desire to make reparation. The second study aimed to test the relationship between guilt/shame and reparation of white South Africans in the field. Furthermore, the second study aimed to account for the dialectical aspects of the intergroup situation by exploring guilt/shame and reparation of white South Africans as expected by young black South Africans (as members of the previously oppressed group). The third study aimed to replicate the differences between experienced guilt/shame/reparation and reported ingroup identification by white South Africans and the expected guilt/shame/reparation from white South Africans and reported ingroup identification by black South Africans as found in the study 2. In addition, the third study aimed to control the antecedents for collective guilt and for collective shame. It also explored the impact knowledge about atrocities of the ingroup (white participants) has on emotions and reparation attitudes and whether perceived status relations at present and in the future impacts the emotions as well general reparation attitudes.
- Full Text:
- Date Issued: 2009
Curiosity first, applications later
- Berold, Robert, Limson, Janice L
- Authors: Berold, Robert , Limson, Janice L
- Date: 2009
- Subjects: Nyokong, Tebello
- Language: English
- Type: Article , text
- Identifier: vital:7188 , http://hdl.handle.net/10962/d1006281 , http://www.sajs.co.za/sites/default/files/publications/pdf/1-4-1-PB.pdf , Nyokong, Tebello
- Description: Tebello Nyokong speaks to Robert Berold and Janice Limson about her career as a chemist. Tebello Nyokong, who holds a research chair in medicinal chemistry and nanotechnology at Rhodes University, has become the first South African scientist to win the L’Oreal-UNESCO award for women in science, in the physical sciences. Only one laureate is selected from each of five world regions, and Nyokong is the 2009 laureate for Africa and the Arab states. She and the winners from the other four regions travel to Paris in March to each accept the award and a generous prize of close to R1 million. Nyokong now heads the new Nanotechnology Innovation Centre for medical sensors: the biggest single research investment in the history of Rhodes. Linked to other nanotechnology centres in the country, it is designed to bridge the gap between research and the market.
- Full Text:
- Date Issued: 2009
- Authors: Berold, Robert , Limson, Janice L
- Date: 2009
- Subjects: Nyokong, Tebello
- Language: English
- Type: Article , text
- Identifier: vital:7188 , http://hdl.handle.net/10962/d1006281 , http://www.sajs.co.za/sites/default/files/publications/pdf/1-4-1-PB.pdf , Nyokong, Tebello
- Description: Tebello Nyokong speaks to Robert Berold and Janice Limson about her career as a chemist. Tebello Nyokong, who holds a research chair in medicinal chemistry and nanotechnology at Rhodes University, has become the first South African scientist to win the L’Oreal-UNESCO award for women in science, in the physical sciences. Only one laureate is selected from each of five world regions, and Nyokong is the 2009 laureate for Africa and the Arab states. She and the winners from the other four regions travel to Paris in March to each accept the award and a generous prize of close to R1 million. Nyokong now heads the new Nanotechnology Innovation Centre for medical sensors: the biggest single research investment in the history of Rhodes. Linked to other nanotechnology centres in the country, it is designed to bridge the gap between research and the market.
- Full Text:
- Date Issued: 2009
An evaluation of the brand campus concept implemented at Mercedes-Benz South Africa: a case study
- Authors: Samkange, Tichaona
- Date: 2009
- Subjects: Mercedes-Benz of South Africa DaimlerChrysler -- South Africa Consumer satisfaction Case studies -- South Africa Product management Case studies -- South Africa Brand name products -- Management Case studies Brand name products -- Valuation Case studies Marketing Case studies -- South Africa Brand choices Case studies -- South Africa Customer preferences Case studies -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:741 , http://hdl.handle.net/10962/d1003861
- Description: Primarily, this research study was concerned with the evaluation of the brand campus concept implemented at then DaimlerChrysler South Africa in 2002, as a case study. Pretoria-based Mercedes-Benz South Africa (Pty) Ltd. (MBSA) is a subsidiary of global vehicle manufacturer Germany’s Daimler-Benz AG (DBAG). They are responsible for assembling, distributing and retailing, certain Mercedes-Benz and Mitsubishi vehicle brands, and spare parts. The landmark 1998 DaimlerChrysler global ‘merger of equals’ was preceded by the 1995 joint venture between Mercedes-Benz and Mitsubishi Motor Corporation. Consequently, three brands (Mercedes-Benz, Chrysler and Mitsubishi) were retailed and marketed under DaimlerChrysler South Africa (Pty) Ltd. (DCSA), positioned next to each other in the same showroom. This report identifies key challenges stemming from this approach, namely: brand strength dilution, more than 80 multi-franchised dealers and multi-branded showrooms, service capacity problems, old working environment and infrastructure, and perceived intra-brand competition. The research evidence suggests that these problems prompted then DCSA to launch the 2000 Dealer Network Strategy (DNS). In the grand scheme of things, the DNS intervention entailed partitioning the dealer network into five brand centres in five metro regions, and eighteen market centres in the rural areas. The brand campus concept was borne out of DNS and proved to be a masterstroke since, the primary focus was on streamlining the retail facilities for DCSA vehicle sales, service and spare parts for both the passenger and commercial vehicles. This study highlights key pillars of the brand campus concept, namely: profitability, brand focus, customer orientation and diversity. The challenge was to address seven major drivers of the brand campus concept, namely: after-sales vehicle support, vehicle service capacity, lead-times, spare parts availability, sales information propagation, behavior of sales personnel and the overall vehicle dealership appearance. Semi-structured interviews constituted part of the evaluation based on the perspectives of five customers, three dealer principals and two MBSA marketing executives. The research evidence, which also came from MBSA documentation and direct observation, shows that this innovative concept has been remarkably successful.
- Full Text:
- Date Issued: 2009
- Authors: Samkange, Tichaona
- Date: 2009
- Subjects: Mercedes-Benz of South Africa DaimlerChrysler -- South Africa Consumer satisfaction Case studies -- South Africa Product management Case studies -- South Africa Brand name products -- Management Case studies Brand name products -- Valuation Case studies Marketing Case studies -- South Africa Brand choices Case studies -- South Africa Customer preferences Case studies -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:741 , http://hdl.handle.net/10962/d1003861
- Description: Primarily, this research study was concerned with the evaluation of the brand campus concept implemented at then DaimlerChrysler South Africa in 2002, as a case study. Pretoria-based Mercedes-Benz South Africa (Pty) Ltd. (MBSA) is a subsidiary of global vehicle manufacturer Germany’s Daimler-Benz AG (DBAG). They are responsible for assembling, distributing and retailing, certain Mercedes-Benz and Mitsubishi vehicle brands, and spare parts. The landmark 1998 DaimlerChrysler global ‘merger of equals’ was preceded by the 1995 joint venture between Mercedes-Benz and Mitsubishi Motor Corporation. Consequently, three brands (Mercedes-Benz, Chrysler and Mitsubishi) were retailed and marketed under DaimlerChrysler South Africa (Pty) Ltd. (DCSA), positioned next to each other in the same showroom. This report identifies key challenges stemming from this approach, namely: brand strength dilution, more than 80 multi-franchised dealers and multi-branded showrooms, service capacity problems, old working environment and infrastructure, and perceived intra-brand competition. The research evidence suggests that these problems prompted then DCSA to launch the 2000 Dealer Network Strategy (DNS). In the grand scheme of things, the DNS intervention entailed partitioning the dealer network into five brand centres in five metro regions, and eighteen market centres in the rural areas. The brand campus concept was borne out of DNS and proved to be a masterstroke since, the primary focus was on streamlining the retail facilities for DCSA vehicle sales, service and spare parts for both the passenger and commercial vehicles. This study highlights key pillars of the brand campus concept, namely: profitability, brand focus, customer orientation and diversity. The challenge was to address seven major drivers of the brand campus concept, namely: after-sales vehicle support, vehicle service capacity, lead-times, spare parts availability, sales information propagation, behavior of sales personnel and the overall vehicle dealership appearance. Semi-structured interviews constituted part of the evaluation based on the perspectives of five customers, three dealer principals and two MBSA marketing executives. The research evidence, which also came from MBSA documentation and direct observation, shows that this innovative concept has been remarkably successful.
- Full Text:
- Date Issued: 2009
The development of sustainability criteria to facilitate the selection of sanitation technologies within the Buffalo City Municipality (Eastern Cape Province, South Africa)
- Authors: Hoossein, Shafick
- Date: 2009
- Subjects: Sanitation -- South Africa -- Buffalo City Sustainable development -- South Africa -- Buffalo City Water -- Purification -- South Africa -- Buffalo City Sewage disposal -- South Africa -- Buffalo City Water quality -- South Africa -- Buffalo City Environmental health -- South Africa -- Buffalo City Environmental management -- South Africa -- Buffalo City
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:32275 , http://hdl.handle.net/10962/d1004595
- Description: Two and a half billion people mostly in sub-Saharan Africa and southern Asia remain without improved sanitation facilities despite the Millennium Development Goal 7's target to halve this number by 2015. While it might be tempting for developing countries such as South Africa to implement the cheapest and most rapidly constructed sanitation services simply to meet the desired target, this could have significant negative implications on human health and the environment over the long-term. As a result, there is a need to ensure that the most appropriate sustainable sanitation technologies are selected during the planning stage. The purpose of this research was therefore to document the development and pilot application of a flexible context-specific decision-support tool for sustainable sanitation technology selection within Buffalo City Municipality (BCM) in the Eastern Cape Province of South Africa. The first step in the development process was to ascertain the current status of sanitation within the municipality, with a specific focus on the main challenges related to the provision, maintenance and performance of these technologies. Thereafter, a participatory approach was employed involving BCM stakeholders to develop a series of sustainability criteria and indicators that took into consideration economic, social, environmental and technical concerns as well as legal requirements. The development process resulted in a list of 38 BCM sustainable sanitation selection criteria that were applied in a pilot study involving rural, urban and peri-urban communities within BCM. Certain criteria related to topographical features and the availability of piped water and land were considered useful for 'coarse screening' while others were applied during 'fine screening'. In order to enhance the context specificity of criteria, each was weighted, through consultation with key BCM stakeholders. This research confirmed that the sanitation situation in BCM was poor and preliminary evidence indicated that sanitation systems were negatively impacting on the quality of water resources within BCM justifying the need for a sustainable sanitation decision support tool. Based on the pilot application of the BCM Sustainability Selection Criteria List, the urine diversion technology was considered the most sustainable technology option in each study site. There were however, certain social criteria that received relatively low sustainability scores and these would need to be addressed prior to the approval of this technology for implementation. The approach adopted in this thesis was considered highly context-specific yet flexible and appropriate for adoption not only by BCM but other municipalities on a range of spatial scales.
- Full Text:
- Date Issued: 2009
- Authors: Hoossein, Shafick
- Date: 2009
- Subjects: Sanitation -- South Africa -- Buffalo City Sustainable development -- South Africa -- Buffalo City Water -- Purification -- South Africa -- Buffalo City Sewage disposal -- South Africa -- Buffalo City Water quality -- South Africa -- Buffalo City Environmental health -- South Africa -- Buffalo City Environmental management -- South Africa -- Buffalo City
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:32275 , http://hdl.handle.net/10962/d1004595
- Description: Two and a half billion people mostly in sub-Saharan Africa and southern Asia remain without improved sanitation facilities despite the Millennium Development Goal 7's target to halve this number by 2015. While it might be tempting for developing countries such as South Africa to implement the cheapest and most rapidly constructed sanitation services simply to meet the desired target, this could have significant negative implications on human health and the environment over the long-term. As a result, there is a need to ensure that the most appropriate sustainable sanitation technologies are selected during the planning stage. The purpose of this research was therefore to document the development and pilot application of a flexible context-specific decision-support tool for sustainable sanitation technology selection within Buffalo City Municipality (BCM) in the Eastern Cape Province of South Africa. The first step in the development process was to ascertain the current status of sanitation within the municipality, with a specific focus on the main challenges related to the provision, maintenance and performance of these technologies. Thereafter, a participatory approach was employed involving BCM stakeholders to develop a series of sustainability criteria and indicators that took into consideration economic, social, environmental and technical concerns as well as legal requirements. The development process resulted in a list of 38 BCM sustainable sanitation selection criteria that were applied in a pilot study involving rural, urban and peri-urban communities within BCM. Certain criteria related to topographical features and the availability of piped water and land were considered useful for 'coarse screening' while others were applied during 'fine screening'. In order to enhance the context specificity of criteria, each was weighted, through consultation with key BCM stakeholders. This research confirmed that the sanitation situation in BCM was poor and preliminary evidence indicated that sanitation systems were negatively impacting on the quality of water resources within BCM justifying the need for a sustainable sanitation decision support tool. Based on the pilot application of the BCM Sustainability Selection Criteria List, the urine diversion technology was considered the most sustainable technology option in each study site. There were however, certain social criteria that received relatively low sustainability scores and these would need to be addressed prior to the approval of this technology for implementation. The approach adopted in this thesis was considered highly context-specific yet flexible and appropriate for adoption not only by BCM but other municipalities on a range of spatial scales.
- Full Text:
- Date Issued: 2009
Adherence and non-adherence to antiretroviral treatment in HIV people in Port Elizabeth
- Masokoane, Kgomotso Quentinne
- Authors: Masokoane, Kgomotso Quentinne
- Date: 2009
- Subjects: Antiretroviral agents -- South Africa -- Port Elizabeth , HIV infections -- Treatment -- South Africa -- Port Elizabeth , AIDS (Disease) -- Treatment -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9886 , http://hdl.handle.net/10948/1185 , Antiretroviral agents -- South Africa -- Port Elizabeth , HIV infections -- Treatment -- South Africa -- Port Elizabeth , AIDS (Disease) -- Treatment -- South Africa -- Port Elizabeth
- Description: The introduction of antiretroviral drugs (ARVs) in 1996 transformed the treatment of HIV and AIDS, improving the quality and greatly prolonging the lives of many infected people. HIV (Human Immunodeficiency Virus) is the virus that is believed to cause AIDS. AIDS (Acquired Immune Deficiency Syndrome) is the collection of illnesses or symptoms that ultimately results in death. Antiretroviral (ARVs) drugs or Highly Active Antiretroviral Therapy (HAART) is the treatment that has been applied to combat the HI virus in a bid to slow down the progression of AIDS and ultimately prolong the life of the infected individual. The study aimed to explore and describe the factors contributing to adherence and non-adherence to ARVs in individuals on treatment. A sample of 81 individuals who have been on ARV and HAART treatment for six months or more was used. The methodology used was exploratory-descriptive and the data obtained was quantitative in nature. A biographical questionnaire and questionnaire with questions aimed at ascertaining the possible factors that contribute to individuals either adhering to or defaulting on their treatment, such as side effects and cost of treatment, was administered. The data obtained was analysed by means of descriptive statistics and frequency counts. The results of the study showed that the sample had a fairly high level of adherence. The factors that could undermine adherence were identified as lack of support, as familial and health provider support acts as a motivator to adhere; substance abuse as it can lead to forgetting to take treatment; unemployment and poverty, as these can lead to an inability to return for follow up clinic visits or failure to have food to take with the pills; and the type of treatment regimen whereby the more complex the treatment is the more likely it is that adherence will be difficult to maintain. Suggestions were made as to future research involving antiretroviral therapy (ART). Finally the limitations as well as the value of the research were outlined.
- Full Text:
- Date Issued: 2009
- Authors: Masokoane, Kgomotso Quentinne
- Date: 2009
- Subjects: Antiretroviral agents -- South Africa -- Port Elizabeth , HIV infections -- Treatment -- South Africa -- Port Elizabeth , AIDS (Disease) -- Treatment -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9886 , http://hdl.handle.net/10948/1185 , Antiretroviral agents -- South Africa -- Port Elizabeth , HIV infections -- Treatment -- South Africa -- Port Elizabeth , AIDS (Disease) -- Treatment -- South Africa -- Port Elizabeth
- Description: The introduction of antiretroviral drugs (ARVs) in 1996 transformed the treatment of HIV and AIDS, improving the quality and greatly prolonging the lives of many infected people. HIV (Human Immunodeficiency Virus) is the virus that is believed to cause AIDS. AIDS (Acquired Immune Deficiency Syndrome) is the collection of illnesses or symptoms that ultimately results in death. Antiretroviral (ARVs) drugs or Highly Active Antiretroviral Therapy (HAART) is the treatment that has been applied to combat the HI virus in a bid to slow down the progression of AIDS and ultimately prolong the life of the infected individual. The study aimed to explore and describe the factors contributing to adherence and non-adherence to ARVs in individuals on treatment. A sample of 81 individuals who have been on ARV and HAART treatment for six months or more was used. The methodology used was exploratory-descriptive and the data obtained was quantitative in nature. A biographical questionnaire and questionnaire with questions aimed at ascertaining the possible factors that contribute to individuals either adhering to or defaulting on their treatment, such as side effects and cost of treatment, was administered. The data obtained was analysed by means of descriptive statistics and frequency counts. The results of the study showed that the sample had a fairly high level of adherence. The factors that could undermine adherence were identified as lack of support, as familial and health provider support acts as a motivator to adhere; substance abuse as it can lead to forgetting to take treatment; unemployment and poverty, as these can lead to an inability to return for follow up clinic visits or failure to have food to take with the pills; and the type of treatment regimen whereby the more complex the treatment is the more likely it is that adherence will be difficult to maintain. Suggestions were made as to future research involving antiretroviral therapy (ART). Finally the limitations as well as the value of the research were outlined.
- Full Text:
- Date Issued: 2009
The development of a commercial production process for p-menthane-3,8-diol
- Authors: Rust, Nico
- Date: 2009
- Subjects: Insect pests -- Control , Repellents
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:10427 , http://hdl.handle.net/10948/d1018273
- Description: The synthesis of p-menthane-3,8-diol via the acid-catalyzed cyclization of citronellal in a dilute aqueous sulphuric acid medium was investigated using conventional batch and continuous systems in order to develop a commercial production process for said p-menthane-3,8-diol (PMD). The batch studies conducted during the first part of this study showed that the formation of PMD from citronellal occurs via an intra-molecular Prins reaction that results in the formation of both the desired PMD product, as well as the partially hydrated isopulegol. It was shown that the formationof the by- product, PMD-acetal, results from the reaction between an intermediate, 5-methyl-2- isopropylcyclohexanol, and the citronellal starting material, and not from the reaction between PMD and citronellal as previously reported. Kinetic studies confirmed the existence of a complicated kinetic model. The formation of PMD from citronellal displayed typical pseudo first order kinetics up to conversions of 70 after which the kinetic model becomes complicated as the result of the establishment of quasi equilibrium reactions between PMD and isopulegol (dehydration of PMD and hydration of isopulegol) and between PMD the PMD-acetal, both systems being acid catalysed. The PMD-acetal formation reaction appears to be second order with respect to PMD. Scale-up studies of the batch process to 30L and 50L scales showed that it would be extremely difficult to limit the level of PMD-acetal formation below the desired level of 1 percent, even if citronellal conversions are restricted to about 50 percent. During studies conducted on a commercially availablemicro-structured organic synthesis plant (OSP) it was shown that it is possible to perform the PMD reaction as a continuous process. The results obtained showed that the use of a micro-mixer such as the caterpillar micro-mixer did not provide enough residence time in order for desirable conversions (- 40 percent) to be obtained. By combining themicro-mixer with delay-loops of different thicknesses and lengths, and using increasing reaction temperatures, it was shown that the conversion of citronellal could be improved to some extent, but compared poorly to the expected conversions for a well-stirred batch reactor. By packing selected delay loops with inert SiC particles, improved mass transfer was observed between the organic and aqueous phases as reflected in the increased conversion of citronellal. Using the observations that were made during the use of the OSP, a continuous-flow, tubular reactor system was designed and constructed. Advanced statistical techniques were used to investigate the effect of variables such as temperature, acid concentration, reactor length, flow rate and the organic to aqueous ratio on the rate and selectivity of the reaction. Mathematical models were derived for citronellal conversion, yield of PMD and yield of PMD- acetals, and used to predict the concentrations of citronellal, PMD and PMD-acetals at set experimental conditions. The results obtained showed that it was possible to obtain a product which approached desired specifications.Downstream processing of the PMD reaction mixture as it exits the reactor requires phase separation and neutralization of the acid catalyst solution, followed by further work-up to recover unreacted starting material and intermediates for recycle back to the synthesis reactor, followed by purification of crude PMD to the desired specification. The study showed that neutralization, prior or after phase separation, does not affect the selectivity of the PMD to such a great extent, but does influence the relative conversion due to extended contact of the catalyst with the organic phase after the reaction is terminated. Recovery of unreacted citronellal and isopulegol could be achieved by a simple vacuum evaporation step, which may either be carried out in a batch manner using traditional distillation equipment, or in a continuous process using wiped-film (short path) techniques. It was also shown that selective crystallization of PMD from the crude product mixture by addition of a solvent, such as heptanes or hexane proved to be the best way of achieving the desired product specification.
- Full Text:
- Date Issued: 2009
- Authors: Rust, Nico
- Date: 2009
- Subjects: Insect pests -- Control , Repellents
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:10427 , http://hdl.handle.net/10948/d1018273
- Description: The synthesis of p-menthane-3,8-diol via the acid-catalyzed cyclization of citronellal in a dilute aqueous sulphuric acid medium was investigated using conventional batch and continuous systems in order to develop a commercial production process for said p-menthane-3,8-diol (PMD). The batch studies conducted during the first part of this study showed that the formation of PMD from citronellal occurs via an intra-molecular Prins reaction that results in the formation of both the desired PMD product, as well as the partially hydrated isopulegol. It was shown that the formationof the by- product, PMD-acetal, results from the reaction between an intermediate, 5-methyl-2- isopropylcyclohexanol, and the citronellal starting material, and not from the reaction between PMD and citronellal as previously reported. Kinetic studies confirmed the existence of a complicated kinetic model. The formation of PMD from citronellal displayed typical pseudo first order kinetics up to conversions of 70 after which the kinetic model becomes complicated as the result of the establishment of quasi equilibrium reactions between PMD and isopulegol (dehydration of PMD and hydration of isopulegol) and between PMD the PMD-acetal, both systems being acid catalysed. The PMD-acetal formation reaction appears to be second order with respect to PMD. Scale-up studies of the batch process to 30L and 50L scales showed that it would be extremely difficult to limit the level of PMD-acetal formation below the desired level of 1 percent, even if citronellal conversions are restricted to about 50 percent. During studies conducted on a commercially availablemicro-structured organic synthesis plant (OSP) it was shown that it is possible to perform the PMD reaction as a continuous process. The results obtained showed that the use of a micro-mixer such as the caterpillar micro-mixer did not provide enough residence time in order for desirable conversions (- 40 percent) to be obtained. By combining themicro-mixer with delay-loops of different thicknesses and lengths, and using increasing reaction temperatures, it was shown that the conversion of citronellal could be improved to some extent, but compared poorly to the expected conversions for a well-stirred batch reactor. By packing selected delay loops with inert SiC particles, improved mass transfer was observed between the organic and aqueous phases as reflected in the increased conversion of citronellal. Using the observations that were made during the use of the OSP, a continuous-flow, tubular reactor system was designed and constructed. Advanced statistical techniques were used to investigate the effect of variables such as temperature, acid concentration, reactor length, flow rate and the organic to aqueous ratio on the rate and selectivity of the reaction. Mathematical models were derived for citronellal conversion, yield of PMD and yield of PMD- acetals, and used to predict the concentrations of citronellal, PMD and PMD-acetals at set experimental conditions. The results obtained showed that it was possible to obtain a product which approached desired specifications.Downstream processing of the PMD reaction mixture as it exits the reactor requires phase separation and neutralization of the acid catalyst solution, followed by further work-up to recover unreacted starting material and intermediates for recycle back to the synthesis reactor, followed by purification of crude PMD to the desired specification. The study showed that neutralization, prior or after phase separation, does not affect the selectivity of the PMD to such a great extent, but does influence the relative conversion due to extended contact of the catalyst with the organic phase after the reaction is terminated. Recovery of unreacted citronellal and isopulegol could be achieved by a simple vacuum evaporation step, which may either be carried out in a batch manner using traditional distillation equipment, or in a continuous process using wiped-film (short path) techniques. It was also shown that selective crystallization of PMD from the crude product mixture by addition of a solvent, such as heptanes or hexane proved to be the best way of achieving the desired product specification.
- Full Text:
- Date Issued: 2009
How can I create a stimulating environment to promote awareness of and love for reading in my classroom?
- Authors: Jantjies, Beverley Esther
- Date: 2009
- Subjects: Reading (Primary) , Reading (Early childhood) , Reading readiness , Reading -- Language experience approach
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:9523 , http://hdl.handle.net/10948/987 , Reading (Primary) , Reading (Early childhood) , Reading readiness , Reading -- Language experience approach
- Description: This study critically examines my classroom practice in teaching young learners aged four-and-a-half to six years old. It focuses on the following research question: How can I create a stimulating environment in my classroom to promote awareness of and a love for reading? My classroom-based action research methodology places me, the practitioner, at the centre of the investigation. The work examines closely my professional values and my strong belief in the capacity of learners to be curious, absorb and make sense of what they encounter and experience in a stimulating environment. It investigates how such an environment develops the potential of learners to love and embrace reading. The process of engaging reflectively and analytically in practitioner research has helped me to gain a better understanding of my learners’ needs and to improve the ways in which I promote reading in the reception year of formal schooling. I claim that the creating of a stimulating environment in my classroom is grounded in my ability to motivate, model and scaffold the learners to engage in reading confidently. Together, the learners and I have created a living theory of education, one that is open to further reflection and development. Ongoing interaction between theoretical discourse and practical experiences enable me to develop my professional knowledge and to synthesize my values and practice. The investigation continuously confirms the advantages of a print-rich environment and how it can be used to promote a love for reading amongst young learners. The claims and knowledge generated in this study are personal and true for me, while the living transformational process demonstrates how I have developed professionally.
- Full Text:
- Date Issued: 2009
- Authors: Jantjies, Beverley Esther
- Date: 2009
- Subjects: Reading (Primary) , Reading (Early childhood) , Reading readiness , Reading -- Language experience approach
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:9523 , http://hdl.handle.net/10948/987 , Reading (Primary) , Reading (Early childhood) , Reading readiness , Reading -- Language experience approach
- Description: This study critically examines my classroom practice in teaching young learners aged four-and-a-half to six years old. It focuses on the following research question: How can I create a stimulating environment in my classroom to promote awareness of and a love for reading? My classroom-based action research methodology places me, the practitioner, at the centre of the investigation. The work examines closely my professional values and my strong belief in the capacity of learners to be curious, absorb and make sense of what they encounter and experience in a stimulating environment. It investigates how such an environment develops the potential of learners to love and embrace reading. The process of engaging reflectively and analytically in practitioner research has helped me to gain a better understanding of my learners’ needs and to improve the ways in which I promote reading in the reception year of formal schooling. I claim that the creating of a stimulating environment in my classroom is grounded in my ability to motivate, model and scaffold the learners to engage in reading confidently. Together, the learners and I have created a living theory of education, one that is open to further reflection and development. Ongoing interaction between theoretical discourse and practical experiences enable me to develop my professional knowledge and to synthesize my values and practice. The investigation continuously confirms the advantages of a print-rich environment and how it can be used to promote a love for reading amongst young learners. The claims and knowledge generated in this study are personal and true for me, while the living transformational process demonstrates how I have developed professionally.
- Full Text:
- Date Issued: 2009
Students as Agents of Social Change-Student Initiatives at Rhodes University, South Africa
- Authors: Togo, Muchaiteyi
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/386561 , vital:68151 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122830"
- Description: Rhodes University has a diversity of sustainable development initiatives meant for students and in a range of cases activities are initiated by students themselves with the support of the university. Results of a sustainability assessment revealed the involvement of students in environmental societies, environmental awareness campaigns, campus sustainability initiatives and community sustainability projects. Though most of the projects are still in their infancy and some challenges are yet to be overcome, the sustainability initiatives are gaining momentum and have contributed to improving the overall picture of sustainability at the university. Based on the results of the Rhodes University case study, the underpinning viewpoint in this paper is that university students are not merely recipients of Education for Sustainable Development but have the capacity to become agents for social change.
- Full Text:
- Date Issued: 2009
- Authors: Togo, Muchaiteyi
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/386561 , vital:68151 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122830"
- Description: Rhodes University has a diversity of sustainable development initiatives meant for students and in a range of cases activities are initiated by students themselves with the support of the university. Results of a sustainability assessment revealed the involvement of students in environmental societies, environmental awareness campaigns, campus sustainability initiatives and community sustainability projects. Though most of the projects are still in their infancy and some challenges are yet to be overcome, the sustainability initiatives are gaining momentum and have contributed to improving the overall picture of sustainability at the university. Based on the results of the Rhodes University case study, the underpinning viewpoint in this paper is that university students are not merely recipients of Education for Sustainable Development but have the capacity to become agents for social change.
- Full Text:
- Date Issued: 2009
A social and cultural history of Grahamstown, 1812 to c1845
- Authors: Marshall, Richard Graham
- Date: 2009
- Subjects: Cities and towns -- Growth -- South Africa -- Eastern Cape Community development, Urban -- South Africa -- Eastern Cape Eastern Cape (South Africa) -- History -- 19th Century Grahamstown (South Africa) -- History -- 19th Century Grahamstown (South Africa) -- History -- Social aspects -- 19th Century Grahamstown (South Africa) -- Social conditions -- 19th Century Grahamstown (South Africa) -- Economic conditions -- 19th Century
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2549 , http://hdl.handle.net/10962/d1002401
- Description: This thesis examines the development of Grahamstown from its inception in 1812 to the mid-1840s, paying particular attention to the social and cultural life of the town. It traces the economic development of the town from a military outpost to a thriving commercial settlement, noting the essential factor of the town's proximity to the Cape frontier in this process. The economic interaction between diverse groups in the town mirrors the social and cultural interaction which occurred between British settlers, Khoekhoe and Africans. The result of these interactions was the creation of a new, distinctively South African urban society and culture, despite the desire of the white settlers to reproduce a “typical” English environment in their new home. The conflict between attempts to anglicise the urban environment and the realities of Grahamstown's situation on a colonial frontier was reflected in the architecture and layout of the town. Attempts to recreate an English social environment also failed. New classes arose in the town in response to the economic opportunities available on the frontier. Although some settlers prospered, many did not, and the presence of an impoverished white working class undermines settler historians' picture of settler success and affluence. The poorest people in the town, though, were the increasing numbers of Khoekhoe and Africans who migrated from the surrounding countryside, and who were unequally incorporated into the urban community as a colonial labouring class. In response to these unique circumstances, white settlers in Grahamstown developed a powerful political and propaganda machine, which helped lay the foundations of a distinct settler identity in the eastern Cape.
- Full Text:
- Date Issued: 2009
- Authors: Marshall, Richard Graham
- Date: 2009
- Subjects: Cities and towns -- Growth -- South Africa -- Eastern Cape Community development, Urban -- South Africa -- Eastern Cape Eastern Cape (South Africa) -- History -- 19th Century Grahamstown (South Africa) -- History -- 19th Century Grahamstown (South Africa) -- History -- Social aspects -- 19th Century Grahamstown (South Africa) -- Social conditions -- 19th Century Grahamstown (South Africa) -- Economic conditions -- 19th Century
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2549 , http://hdl.handle.net/10962/d1002401
- Description: This thesis examines the development of Grahamstown from its inception in 1812 to the mid-1840s, paying particular attention to the social and cultural life of the town. It traces the economic development of the town from a military outpost to a thriving commercial settlement, noting the essential factor of the town's proximity to the Cape frontier in this process. The economic interaction between diverse groups in the town mirrors the social and cultural interaction which occurred between British settlers, Khoekhoe and Africans. The result of these interactions was the creation of a new, distinctively South African urban society and culture, despite the desire of the white settlers to reproduce a “typical” English environment in their new home. The conflict between attempts to anglicise the urban environment and the realities of Grahamstown's situation on a colonial frontier was reflected in the architecture and layout of the town. Attempts to recreate an English social environment also failed. New classes arose in the town in response to the economic opportunities available on the frontier. Although some settlers prospered, many did not, and the presence of an impoverished white working class undermines settler historians' picture of settler success and affluence. The poorest people in the town, though, were the increasing numbers of Khoekhoe and Africans who migrated from the surrounding countryside, and who were unequally incorporated into the urban community as a colonial labouring class. In response to these unique circumstances, white settlers in Grahamstown developed a powerful political and propaganda machine, which helped lay the foundations of a distinct settler identity in the eastern Cape.
- Full Text:
- Date Issued: 2009
Synthesis and characterization of novel platinum complexes : their anticancer behaviour
- Authors: Myburgh, Jolanda
- Date: 2009
- Subjects: Complex compounds -- Synthesis , Platinum compounds , Antineoplastic agents
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10429 , http://hdl.handle.net/10948/d1018621
- Description: In this dissertation novel non-leaving groups were employed to synthesize platinum complexes which can contribute to the understanding or improvement of anticancer action. These complexes basically consist of (NS)-chelate and amineplatinum complexes. Bidentate (NS)-donor ligands were used as non-leaving ligands in the syntheses of platinum(II) complexes with iodide, chloride, bromide and oxalate anions as leaving groups. These complexes were synthesized and studied since many questions regarding the interaction of sulfur donors and platinum still exists. These relate to thermodynamic and kinetic factors and their influence on anticancer action. In this dissertation the properties of novel platinum(II) complexes of a bidentate ligand having an aromatic nitrogen-donor atom in combination with a thioethereal sulfur atom capable of forming a five membered ring with platinum(II) were studied. The general structure of the (NS) -ligands used were N-alkyl-2-methylthioalkyl imidazole. Alkyl groups used were methyl, ethyl and propyl. Although amine complexes of platinum have been extensively studied there are some new aspects of these that are worthwhile investigating. In this dissertation amines having planar attachments which will be at an angle with the coordination plane viz. benzylamine and amines having cyclic aliphatic groups namely cyclopropyl and cyclohexyl were investigated. Some of the (NS) - and amineplatinum(II) complexes were oxidised to their mononitroplatinum(IV) analogues . The motivation for the synthesis of these complexes was the greater kinetic stability of platinum(IV) and recent research has shown that a specific type of platinum(IV) compound shows suitable properties as an anticancer agent. These complexes were characterised by a variety of spectral means (IR, NMR, mass spectroscopy) as well as elemental analysis, solubility determinations, thermal analysis (TGA), ionization studies and finally their anticancer behaviour towards three different cell lines(Hela, MCF 7, Ht29) and in this process they were compared to the behaviour of cisplatin as a reference. A few have shown promising anticancer behaviour.
- Full Text:
- Date Issued: 2009
- Authors: Myburgh, Jolanda
- Date: 2009
- Subjects: Complex compounds -- Synthesis , Platinum compounds , Antineoplastic agents
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10429 , http://hdl.handle.net/10948/d1018621
- Description: In this dissertation novel non-leaving groups were employed to synthesize platinum complexes which can contribute to the understanding or improvement of anticancer action. These complexes basically consist of (NS)-chelate and amineplatinum complexes. Bidentate (NS)-donor ligands were used as non-leaving ligands in the syntheses of platinum(II) complexes with iodide, chloride, bromide and oxalate anions as leaving groups. These complexes were synthesized and studied since many questions regarding the interaction of sulfur donors and platinum still exists. These relate to thermodynamic and kinetic factors and their influence on anticancer action. In this dissertation the properties of novel platinum(II) complexes of a bidentate ligand having an aromatic nitrogen-donor atom in combination with a thioethereal sulfur atom capable of forming a five membered ring with platinum(II) were studied. The general structure of the (NS) -ligands used were N-alkyl-2-methylthioalkyl imidazole. Alkyl groups used were methyl, ethyl and propyl. Although amine complexes of platinum have been extensively studied there are some new aspects of these that are worthwhile investigating. In this dissertation amines having planar attachments which will be at an angle with the coordination plane viz. benzylamine and amines having cyclic aliphatic groups namely cyclopropyl and cyclohexyl were investigated. Some of the (NS) - and amineplatinum(II) complexes were oxidised to their mononitroplatinum(IV) analogues . The motivation for the synthesis of these complexes was the greater kinetic stability of platinum(IV) and recent research has shown that a specific type of platinum(IV) compound shows suitable properties as an anticancer agent. These complexes were characterised by a variety of spectral means (IR, NMR, mass spectroscopy) as well as elemental analysis, solubility determinations, thermal analysis (TGA), ionization studies and finally their anticancer behaviour towards three different cell lines(Hela, MCF 7, Ht29) and in this process they were compared to the behaviour of cisplatin as a reference. A few have shown promising anticancer behaviour.
- Full Text:
- Date Issued: 2009
Synthesis, photophysical and nonlinear optical properties of microwave synthesized 4-tetra and octa-substituted lead phthalocyanines
- Modibane, Desmond K, Nyokong, Tebello
- Authors: Modibane, Desmond K , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/263452 , vital:53629 , xlink:href="https://doi.org/10.1016/j.poly.2009.03.013"
- Description: This work presents the photophysical and nonlinear optical behaviour of newly synthesized complexes: 2,(3)-tetrakis(4-benzyloxyphenoxyphthalocyaninato) lead (5a) and 2,3-octakis(4-benzyloxyphenoxyphthalocyaninato) lead (6a). The nonlinear optical behaviour of complexes 5a and 6a are compared with those of 2,(3)-tetraphenoxyphthalocyaninato lead (5b), 2,(3)-tetrakis(4-t-butylphenoxyphthalocyaninato) lead (5c), 2,3-octaphenoxyphthalocyaninato lead (6b) and 2,3-octakis(4-t-butylphenoxyphthalocyaninato) lead (6c). The synthesis of 5a and 6a was performed using microwave irradiation. Photophysical properties were studied for these complexes in dimethylsulfoxide, dimethylformamide, toluene, tetrahydrofuran and chloroform. The fluorescence spectra were different from excitation spectra due to demetallation upon excitation. High triplet quantum yields ranging from 0.80 to 0.86 (in DMSO, DMF and toluene) and low triplet lifetimes (20–50 μs in DMSO, and more than 10 μs in the rest of the solvents) were observed due to the presence of heavy atom. Nonlinear optical properties were studied in dimethylsulfoxide. The optical limiting threshold intensity (Ilim) for the PbPc derivatives were calculated and ranged from 2.1 to 6.6 W/cm2.
- Full Text:
- Date Issued: 2009
- Authors: Modibane, Desmond K , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/263452 , vital:53629 , xlink:href="https://doi.org/10.1016/j.poly.2009.03.013"
- Description: This work presents the photophysical and nonlinear optical behaviour of newly synthesized complexes: 2,(3)-tetrakis(4-benzyloxyphenoxyphthalocyaninato) lead (5a) and 2,3-octakis(4-benzyloxyphenoxyphthalocyaninato) lead (6a). The nonlinear optical behaviour of complexes 5a and 6a are compared with those of 2,(3)-tetraphenoxyphthalocyaninato lead (5b), 2,(3)-tetrakis(4-t-butylphenoxyphthalocyaninato) lead (5c), 2,3-octaphenoxyphthalocyaninato lead (6b) and 2,3-octakis(4-t-butylphenoxyphthalocyaninato) lead (6c). The synthesis of 5a and 6a was performed using microwave irradiation. Photophysical properties were studied for these complexes in dimethylsulfoxide, dimethylformamide, toluene, tetrahydrofuran and chloroform. The fluorescence spectra were different from excitation spectra due to demetallation upon excitation. High triplet quantum yields ranging from 0.80 to 0.86 (in DMSO, DMF and toluene) and low triplet lifetimes (20–50 μs in DMSO, and more than 10 μs in the rest of the solvents) were observed due to the presence of heavy atom. Nonlinear optical properties were studied in dimethylsulfoxide. The optical limiting threshold intensity (Ilim) for the PbPc derivatives were calculated and ranged from 2.1 to 6.6 W/cm2.
- Full Text:
- Date Issued: 2009
On location: Narratives of the South African city of the late 1940s and 1950s in film and literature
- Authors: Baines, Gary F
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125397 , vital:35779 , https://doi.10.1080/02582470308671922
- Description: This article is about narratives, about the forms and meanings constructed by South African storytellers, especially writers and filmmakers. It examines the relationships between examples of these two different narrative forms of literature (fiction and non-fiction) and feature film. Following Turner, the point of departure is that the study of narrative has the potential to provide a framework within which such a two pronged approach can be undertaken. This is not to say that the production of meaning takes place within an exclusive literary or cinematic context. Rather, this approach will allow us to obtain a fuller picture of the narrative of the South African city than is possible by concentrating on one medium. It is based on the premise that narratives are ultimately produced by culture; thus these cultural constructions generate meanings, take on a significance, and assume forms that are articufations of the values, beliefs -the ideology - of the culture.' Literature and film offer specific forms for such narratives. By adopting an interdisciplinary approach which borrows insights from literary and film studies, this article attempts to make a contribution to the fledgling field of South African cultural studies.
- Full Text:
- Date Issued: 2009
On location: Narratives of the South African city of the late 1940s and 1950s in film and literature
- Authors: Baines, Gary F
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125397 , vital:35779 , https://doi.10.1080/02582470308671922
- Description: This article is about narratives, about the forms and meanings constructed by South African storytellers, especially writers and filmmakers. It examines the relationships between examples of these two different narrative forms of literature (fiction and non-fiction) and feature film. Following Turner, the point of departure is that the study of narrative has the potential to provide a framework within which such a two pronged approach can be undertaken. This is not to say that the production of meaning takes place within an exclusive literary or cinematic context. Rather, this approach will allow us to obtain a fuller picture of the narrative of the South African city than is possible by concentrating on one medium. It is based on the premise that narratives are ultimately produced by culture; thus these cultural constructions generate meanings, take on a significance, and assume forms that are articufations of the values, beliefs -the ideology - of the culture.' Literature and film offer specific forms for such narratives. By adopting an interdisciplinary approach which borrows insights from literary and film studies, this article attempts to make a contribution to the fledgling field of South African cultural studies.
- Full Text:
- Date Issued: 2009
The economic contribution of trout fly-fishing to the economy of the rhodes region
- Authors: Gatogang, Ballbo Patric
- Date: 2009
- Subjects: Trout fishing -- South Africa , Rainbow trout fisheries , Fishery management -- Economic aspects , Fishery management -- South Africa , Fly-fishing -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:8991 , http://hdl.handle.net/10948/919 , Trout fishing -- South Africa , Rainbow trout fisheries , Fishery management -- Economic aspects , Fishery management -- South Africa , Fly-fishing -- South Africa
- Description: Approximately 24 alien fish species, equivalent to 9 percent of all South African freshwater fish species, were introduced and established into South African waters during the 19th and 20th Centuries (Skelton, 2001). Of the 24 species introduced, the Rainbow trout and the Brown trout have over time become South Africa's most widely spread and used freshwater fish species (Bainbridge, Alletson, Davies, Lax and Mills, 2005). The National Environmental Management: Biodiversity Act, no.10 of 2004 has, however, cast considerable doubt on the future of trout as a food source and a recreational fishing resource in South Africa. More specifically, Section 64 of the Act has the following aims: “(a) to prevent the unauthorized introduction and spread of alien species and invasive species to ecosystems and habitats where they do not naturally occur; (b) to manage and control alien species and invasive species to prevent or minimize harm to the environment and to biodiversity in particular; and (c) to eradicate alien species and invasive species from ecosystems and habitats where they may harm such ecosystems or habitats.” The uncertainty surrounding the future of trout in South Africa is mainly underpinned by aim (c) of Section 64 of the Act. Regarding the eradication of trout and in keeping with aim (c) of Section 64 of the Act, three remarks can be made. First, there exists a paucity of published studies which offer validated proof of the impacts which may be ascribed entirely to the introduction of alien trout in South Africa, since no pre-stocking assessments were conducted (Bainbridge et al., 2005). Second, the elimination of trout is feasible in a few limited closed ecosystems, such as small dams, but is highly impractical and untenable from an environmental and cost perspective where open and established river systems are concerned (Bainbridge et al., x 2005). More specifically, there are no efficient or adequate eradication measures which may be used in wide-ranging open ecosystems, which selectively target alien fish species. Moreover, most, if not all, measures have the potential to cause considerable adverse impacts on indigenous aquafaunal species. Finally, the elimination of trout could undermine the tourism appeal of many upper catchment areas in South Africa. The trout fishing industry is well established and is a source of local and foreign income, as well as a job creator in the South African economy (Bainbridge et al., 2005; Hlatswako, 2000; Rogerson, 2002). In particular, the industry provides a two-tier service: first, in food production at the subsistence as well as commercial levels, and second, as an angling resource. Recreational angling, including fly-fishing for trout, is one of the fastest growing tourism attractions in South Africa. Furthermore, the trout fishing industry is sustained and underpinned by a considerable infrastructure consisting of tackle manufacturers and retailers, tourist operators, professional guides, hotels, lodges and B&Bs. The economic case for the trout fishing industry in South Africa has, however, not been convincingly made. The economic benefit provided by trout and trout fly-fishing is priced directly in the market place by expenditures made by fly-fishers, and indirectly in property values, which provide access to fly-fishing opportunities. The benefit of trout and trout fly-fishing can also be valued through non-market valuation techniques. Non-market valuation is used to calculate values for items that are not traded in markets, such as environmental services. There are several non-market valuation methods available to the researcher, namely those based on revealed preference and those based on stated preference. The former includes the hedonic pricing method and the travel cost method, while the latter includes the contingent valuation method and the choice modelling method. Of the available non-market valuation techniques, the travel cost method is the most suitable method for determining the value of trout and the trout fishing industry because travel cost is often the main expenditure incurred. xi The aim of this study is threefold: first, to value the economic contribution of trout and trout fly-fishing to the Rhodes region, North Eastern Cape; second, to determine the willingness-to-pay for a project that entails the rehabilitation and maintenance of trout streams and rivers in and around Rhodes village so as to increase their trout carrying capacity by 10 percent; third, to determine the willingness-to-pay for a project aimed at eradicating trout from streams and rivers in and around Rhodes village so as to prevent trout from harming the indigenous yellowfish habitat. The first aim was achieved by applying the travel cost method, whereas the second and third aims were achieved by applying the contingent valuation method. The study aimed to provide policy makers with information regarding the value of trout fishing in the Rhodes region, so as to create an awareness of the economic trade-offs associated with alien fish eradication. Through the application of the travel cost method, the consumer surplus per trout fly-fishermen was estimated to be R19 677.69, while the total consumer surplus was estimated to be R13 774 384.40. The median willingness-to-pay for a project to rehabilitate trout habitat was estimated to be R248.95, while the total willingness-to-pay amounted to R199 462.20. The median willingness-to-pay for a project to eradicate alien trout from the Rhodes region rivers and streams was estimated to be R41.18, while the total willingness-to-pay amounted to R28 829.36. This study concludes that trout and trout fly-fishing make a valuable economic contribution to the Rhodes region. The extent of the economic benefit provided by trout and trout fly-fishing services in the Rhodes region should be carefully considered in any stream management project.
- Full Text:
- Date Issued: 2009
- Authors: Gatogang, Ballbo Patric
- Date: 2009
- Subjects: Trout fishing -- South Africa , Rainbow trout fisheries , Fishery management -- Economic aspects , Fishery management -- South Africa , Fly-fishing -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:8991 , http://hdl.handle.net/10948/919 , Trout fishing -- South Africa , Rainbow trout fisheries , Fishery management -- Economic aspects , Fishery management -- South Africa , Fly-fishing -- South Africa
- Description: Approximately 24 alien fish species, equivalent to 9 percent of all South African freshwater fish species, were introduced and established into South African waters during the 19th and 20th Centuries (Skelton, 2001). Of the 24 species introduced, the Rainbow trout and the Brown trout have over time become South Africa's most widely spread and used freshwater fish species (Bainbridge, Alletson, Davies, Lax and Mills, 2005). The National Environmental Management: Biodiversity Act, no.10 of 2004 has, however, cast considerable doubt on the future of trout as a food source and a recreational fishing resource in South Africa. More specifically, Section 64 of the Act has the following aims: “(a) to prevent the unauthorized introduction and spread of alien species and invasive species to ecosystems and habitats where they do not naturally occur; (b) to manage and control alien species and invasive species to prevent or minimize harm to the environment and to biodiversity in particular; and (c) to eradicate alien species and invasive species from ecosystems and habitats where they may harm such ecosystems or habitats.” The uncertainty surrounding the future of trout in South Africa is mainly underpinned by aim (c) of Section 64 of the Act. Regarding the eradication of trout and in keeping with aim (c) of Section 64 of the Act, three remarks can be made. First, there exists a paucity of published studies which offer validated proof of the impacts which may be ascribed entirely to the introduction of alien trout in South Africa, since no pre-stocking assessments were conducted (Bainbridge et al., 2005). Second, the elimination of trout is feasible in a few limited closed ecosystems, such as small dams, but is highly impractical and untenable from an environmental and cost perspective where open and established river systems are concerned (Bainbridge et al., x 2005). More specifically, there are no efficient or adequate eradication measures which may be used in wide-ranging open ecosystems, which selectively target alien fish species. Moreover, most, if not all, measures have the potential to cause considerable adverse impacts on indigenous aquafaunal species. Finally, the elimination of trout could undermine the tourism appeal of many upper catchment areas in South Africa. The trout fishing industry is well established and is a source of local and foreign income, as well as a job creator in the South African economy (Bainbridge et al., 2005; Hlatswako, 2000; Rogerson, 2002). In particular, the industry provides a two-tier service: first, in food production at the subsistence as well as commercial levels, and second, as an angling resource. Recreational angling, including fly-fishing for trout, is one of the fastest growing tourism attractions in South Africa. Furthermore, the trout fishing industry is sustained and underpinned by a considerable infrastructure consisting of tackle manufacturers and retailers, tourist operators, professional guides, hotels, lodges and B&Bs. The economic case for the trout fishing industry in South Africa has, however, not been convincingly made. The economic benefit provided by trout and trout fly-fishing is priced directly in the market place by expenditures made by fly-fishers, and indirectly in property values, which provide access to fly-fishing opportunities. The benefit of trout and trout fly-fishing can also be valued through non-market valuation techniques. Non-market valuation is used to calculate values for items that are not traded in markets, such as environmental services. There are several non-market valuation methods available to the researcher, namely those based on revealed preference and those based on stated preference. The former includes the hedonic pricing method and the travel cost method, while the latter includes the contingent valuation method and the choice modelling method. Of the available non-market valuation techniques, the travel cost method is the most suitable method for determining the value of trout and the trout fishing industry because travel cost is often the main expenditure incurred. xi The aim of this study is threefold: first, to value the economic contribution of trout and trout fly-fishing to the Rhodes region, North Eastern Cape; second, to determine the willingness-to-pay for a project that entails the rehabilitation and maintenance of trout streams and rivers in and around Rhodes village so as to increase their trout carrying capacity by 10 percent; third, to determine the willingness-to-pay for a project aimed at eradicating trout from streams and rivers in and around Rhodes village so as to prevent trout from harming the indigenous yellowfish habitat. The first aim was achieved by applying the travel cost method, whereas the second and third aims were achieved by applying the contingent valuation method. The study aimed to provide policy makers with information regarding the value of trout fishing in the Rhodes region, so as to create an awareness of the economic trade-offs associated with alien fish eradication. Through the application of the travel cost method, the consumer surplus per trout fly-fishermen was estimated to be R19 677.69, while the total consumer surplus was estimated to be R13 774 384.40. The median willingness-to-pay for a project to rehabilitate trout habitat was estimated to be R248.95, while the total willingness-to-pay amounted to R199 462.20. The median willingness-to-pay for a project to eradicate alien trout from the Rhodes region rivers and streams was estimated to be R41.18, while the total willingness-to-pay amounted to R28 829.36. This study concludes that trout and trout fly-fishing make a valuable economic contribution to the Rhodes region. The extent of the economic benefit provided by trout and trout fly-fishing services in the Rhodes region should be carefully considered in any stream management project.
- Full Text:
- Date Issued: 2009
An investigation into the role of student participation in school governance : a Namibian perspective
- Authors: Shekupakela-Nelulu, Rauna
- Date: 2009
- Subjects: Education and state -- Namibia Education, Secondary -- Namibia Student government -- Namibia Student participation in administration -- Namibia School management and organization -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1923 , http://hdl.handle.net/10962/d1007449
- Description: The issue of student participation in school governance is not a new concept in Namibian schools. Student involvement dates back to the 1970's when the country's administration was under the South African apartheid regime. Back then the involvement of students in school affairs was seen by the regime as a political act and attempts by student leaders to involve themselves in educational issues were often quashed. When the country became independent student representation continued as Student Representative Councils (SRC's), later renamed Learners Representative Councils (LRCs). This study attempted to investigate the perceptions of LRCs and other stakeholders - narnely the school principals and the school board members - of the role of students in school governance. The study was conducted in three Senior Secondary Schools in the Kavango region in Namibia. The research respondents were school principals, chairpersons of the LRCs and one chairperson of a school board. The study was conducted in the interpretive paradigm employing the following three qualitative research methods interviews, observation and document analysis to collect data. Through triangulation it was possible to formulate a rich response to the research question. The study found that, although the notion of student participation in school governance was widely accepted, a number of challenges exist that hamper the effectiveness of LRCs in the schools. It was revealed that there was no national policy docunlent that outlined the roles and function of the LRCs. As a result schools had little direction about the LRCs and subsequently they were given little or no attention by the school authorities. This resulted in misunderstandings and in some cases conflict between learners and the school management. The most significant consequence of these problems was the fact that LRCs were not regarded as true role players in school governance. The study thus recommends that a national policy document that legitimates the role of students in school governance be drafted to provide direction and that schools embark on meaningful training programmes for LRC members. The study also calls for further research to address the gap in literature on this phenomenon, particularly in Namibia.
- Full Text:
- Date Issued: 2009
- Authors: Shekupakela-Nelulu, Rauna
- Date: 2009
- Subjects: Education and state -- Namibia Education, Secondary -- Namibia Student government -- Namibia Student participation in administration -- Namibia School management and organization -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1923 , http://hdl.handle.net/10962/d1007449
- Description: The issue of student participation in school governance is not a new concept in Namibian schools. Student involvement dates back to the 1970's when the country's administration was under the South African apartheid regime. Back then the involvement of students in school affairs was seen by the regime as a political act and attempts by student leaders to involve themselves in educational issues were often quashed. When the country became independent student representation continued as Student Representative Councils (SRC's), later renamed Learners Representative Councils (LRCs). This study attempted to investigate the perceptions of LRCs and other stakeholders - narnely the school principals and the school board members - of the role of students in school governance. The study was conducted in three Senior Secondary Schools in the Kavango region in Namibia. The research respondents were school principals, chairpersons of the LRCs and one chairperson of a school board. The study was conducted in the interpretive paradigm employing the following three qualitative research methods interviews, observation and document analysis to collect data. Through triangulation it was possible to formulate a rich response to the research question. The study found that, although the notion of student participation in school governance was widely accepted, a number of challenges exist that hamper the effectiveness of LRCs in the schools. It was revealed that there was no national policy docunlent that outlined the roles and function of the LRCs. As a result schools had little direction about the LRCs and subsequently they were given little or no attention by the school authorities. This resulted in misunderstandings and in some cases conflict between learners and the school management. The most significant consequence of these problems was the fact that LRCs were not regarded as true role players in school governance. The study thus recommends that a national policy document that legitimates the role of students in school governance be drafted to provide direction and that schools embark on meaningful training programmes for LRC members. The study also calls for further research to address the gap in literature on this phenomenon, particularly in Namibia.
- Full Text:
- Date Issued: 2009
A Speciation study of the chloro-hydroxo complexes of Pt(II)
- Authors: Davis, John Christopher
- Date: 2009
- Subjects: Platinum , Platinum -- Separation , Platinum compounds
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10388 , http://hdl.handle.net/10948/1213 , Platinum , Platinum -- Separation , Platinum compounds
- Description: In this study a method was developed to identify and quantify platinum(II) complexes of the type [PtCl4-n(OH)n]2- and [PtCl4-n(H2O)n]2-n. Separation of the various species was achieved with the aid of a hyphenated reversed phase HPLC-ICP-MS technique coupled with an ion-pairing reagent, HMHDCl2. The adsorption of HMHD2+ onto a C-18 column was investigated by generating a series of breakthrough curves. It was found that the selectivity for high charge density anions originates from its low surface coverage relative to TBA+, which on the other hand could not separate Pt(II) complexes. The peaks in the chromatographic traces were assigned by following the stepwise ligand substitution of [PtCl4]2- in hydroxide medium with UV/Vis spectrophotometry and HPLC-ICP-MS simultaneously. A computer program was written by the author to analyse chromatographic data by deconvoluting the chromatogram into its individual components and calculating the mole fraction of each component. The validity of the consecutive pseudo-first order model was validated by constructing 3D Mauser diagrams with the raw spectrophotometric data (A1 vs A2 vs A3). Additional software was used to simulate the raw spectrophotometric data and processed chromatographic data. The pseudo-first order rate constants obtained in both cases were in agreement with each other. Hence, peaks were assigned to [PtCl4]2-, [PtCl3(OH)]2-, [PtCl2(OH)2]2-, [PtCl3(H2O)]-. The molar extinction coefficient spectra of [PtCl3(OH)]2- and [PtCl2(OH)2]2- were obtained by simulating the spectrophotometric data at wavelengths from 280 to 450 nm. The reaction of [PtCl4]2- with sodium hydroxide was investigated with UV/Vis spectrophotometry at 25 °C. A rate constant consisting of a first and second order term was obtained. The first order term agreed with what has been reported in the literature for aquation of [PtCl4]2- at 25 degrees C. The influence of temperature was established by conducting the experiment at different temperatures. It was found that the reaction proceeds essentially via aquation at elevated temperatures.
- Full Text:
- Date Issued: 2009
- Authors: Davis, John Christopher
- Date: 2009
- Subjects: Platinum , Platinum -- Separation , Platinum compounds
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10388 , http://hdl.handle.net/10948/1213 , Platinum , Platinum -- Separation , Platinum compounds
- Description: In this study a method was developed to identify and quantify platinum(II) complexes of the type [PtCl4-n(OH)n]2- and [PtCl4-n(H2O)n]2-n. Separation of the various species was achieved with the aid of a hyphenated reversed phase HPLC-ICP-MS technique coupled with an ion-pairing reagent, HMHDCl2. The adsorption of HMHD2+ onto a C-18 column was investigated by generating a series of breakthrough curves. It was found that the selectivity for high charge density anions originates from its low surface coverage relative to TBA+, which on the other hand could not separate Pt(II) complexes. The peaks in the chromatographic traces were assigned by following the stepwise ligand substitution of [PtCl4]2- in hydroxide medium with UV/Vis spectrophotometry and HPLC-ICP-MS simultaneously. A computer program was written by the author to analyse chromatographic data by deconvoluting the chromatogram into its individual components and calculating the mole fraction of each component. The validity of the consecutive pseudo-first order model was validated by constructing 3D Mauser diagrams with the raw spectrophotometric data (A1 vs A2 vs A3). Additional software was used to simulate the raw spectrophotometric data and processed chromatographic data. The pseudo-first order rate constants obtained in both cases were in agreement with each other. Hence, peaks were assigned to [PtCl4]2-, [PtCl3(OH)]2-, [PtCl2(OH)2]2-, [PtCl3(H2O)]-. The molar extinction coefficient spectra of [PtCl3(OH)]2- and [PtCl2(OH)2]2- were obtained by simulating the spectrophotometric data at wavelengths from 280 to 450 nm. The reaction of [PtCl4]2- with sodium hydroxide was investigated with UV/Vis spectrophotometry at 25 °C. A rate constant consisting of a first and second order term was obtained. The first order term agreed with what has been reported in the literature for aquation of [PtCl4]2- at 25 degrees C. The influence of temperature was established by conducting the experiment at different temperatures. It was found that the reaction proceeds essentially via aquation at elevated temperatures.
- Full Text:
- Date Issued: 2009
Valuing preferences for freshwater inflows into selected Western and Southern Cape estuaries
- Authors: Akoto, William
- Date: 2009
- Subjects: Estuarine ecology -- South Africa , Freshwater ecology -- South Africa , Estuaries -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:8992 , http://hdl.handle.net/10948/915 , Estuarine ecology -- South Africa , Freshwater ecology -- South Africa , Estuaries -- South Africa
- Description: An estuary is the last stage of a river. It is where the river meets the sea. Estuaries are one of the most significant features of the South African coastline. In recent years, South Africa has witnessed an increase in the demand for freshwater for both industrial and domestic purposes. At the same time, there has been a gradual deterioration of river systems and their catchments. To add to this, there has been a gradual reduction in the amount of recorded rainfall, which is the primary source of freshwater for rivers. This has resulted in decreased freshwater inflow into estuaries, a situation which poses a serious threat to the biological functioning of these estuaries and the services rendered to its recreational users. A deterioration of estuary services reduces the yield for subsistence households and their appeal for recration. This study uses the contingent valuation method as its primary methodology to elicit users' willingness-to-pay to reduce the negative impacts of reduced freshwater inflow into selected western and southern Cape estuaries. Eight estuaries were selected for this study; the Breede, Duiwenhoks, Great Berg, Kleinemond West, Mhlathuze, Swartvlei and Olifants estuaries. The contingent valuation (CV) method is widely used for studies of this nature because of its ability to capture active, passive and non-use values. The CV method involves directly asking people how much they would be willing to pay for specific environmental services. In this case, users were asked what they would be willing to pay to sustain freshwater inflows into selected estuaries in order to prevent the negative impacts of reduced inflows. The travel cost method (TCM) was uesed to generate an alternative comparative set of values for the purposes of convergence testing. This is because convergence testing is highly desirable as a validity test for CV estimates.
- Full Text:
- Date Issued: 2009
- Authors: Akoto, William
- Date: 2009
- Subjects: Estuarine ecology -- South Africa , Freshwater ecology -- South Africa , Estuaries -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:8992 , http://hdl.handle.net/10948/915 , Estuarine ecology -- South Africa , Freshwater ecology -- South Africa , Estuaries -- South Africa
- Description: An estuary is the last stage of a river. It is where the river meets the sea. Estuaries are one of the most significant features of the South African coastline. In recent years, South Africa has witnessed an increase in the demand for freshwater for both industrial and domestic purposes. At the same time, there has been a gradual deterioration of river systems and their catchments. To add to this, there has been a gradual reduction in the amount of recorded rainfall, which is the primary source of freshwater for rivers. This has resulted in decreased freshwater inflow into estuaries, a situation which poses a serious threat to the biological functioning of these estuaries and the services rendered to its recreational users. A deterioration of estuary services reduces the yield for subsistence households and their appeal for recration. This study uses the contingent valuation method as its primary methodology to elicit users' willingness-to-pay to reduce the negative impacts of reduced freshwater inflow into selected western and southern Cape estuaries. Eight estuaries were selected for this study; the Breede, Duiwenhoks, Great Berg, Kleinemond West, Mhlathuze, Swartvlei and Olifants estuaries. The contingent valuation (CV) method is widely used for studies of this nature because of its ability to capture active, passive and non-use values. The CV method involves directly asking people how much they would be willing to pay for specific environmental services. In this case, users were asked what they would be willing to pay to sustain freshwater inflows into selected estuaries in order to prevent the negative impacts of reduced inflows. The travel cost method (TCM) was uesed to generate an alternative comparative set of values for the purposes of convergence testing. This is because convergence testing is highly desirable as a validity test for CV estimates.
- Full Text:
- Date Issued: 2009
Effects of the number of ring substituents of cobalt carboxyphthalocyanines on the electrocatalytic detection of nitrite, cysteine and melatonin
- Matemadombo, Fungisai, Sehlotho, Nthapo, Nyokong, Tebello
- Authors: Matemadombo, Fungisai , Sehlotho, Nthapo , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/263408 , vital:53625 , xlink:href="https://doi.org/10.1142/S108842460900125X"
- Description: Cobalt phthalocyanine (CoPc), cobalt tetracarboxy phthalocyanine (CoTCPc) and cobalt octacarboxy phthalocyanine (CoOCPc), adsorbed onto glassy carbon electrodes, have been used for the electrocatalytic detection of nitrite, L-cysteine and melatonin. The modified electrodes electrocatalytically detected nitrite around 800 mV vs.Ag|AgCl, a value less positive compared to that of an unmodified glassy carbon electrode (at 950 mV vs.Ag|AgCl) and also gave detection limits in the 10-7 M range for nitrite detection. L-cysteine was detected by the modified electrodes at potentials between 0.50 to 0.65 V vs.Ag|AgCl, with L-cysteine detection limits also in the 10-7 M range. The detection limits for melatonin ranged from 10-7 to 10-6 M. CoPc-modified electrodes displayed good separation of interferents (tryptophan and ascorbic acid) in the presence of melatonin. Analyses of commercial melatonin tablets using modified electrodes gave excellent agreement with manufacturer's value for all modified electrodes of this work.
- Full Text:
- Date Issued: 2009
- Authors: Matemadombo, Fungisai , Sehlotho, Nthapo , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/263408 , vital:53625 , xlink:href="https://doi.org/10.1142/S108842460900125X"
- Description: Cobalt phthalocyanine (CoPc), cobalt tetracarboxy phthalocyanine (CoTCPc) and cobalt octacarboxy phthalocyanine (CoOCPc), adsorbed onto glassy carbon electrodes, have been used for the electrocatalytic detection of nitrite, L-cysteine and melatonin. The modified electrodes electrocatalytically detected nitrite around 800 mV vs.Ag|AgCl, a value less positive compared to that of an unmodified glassy carbon electrode (at 950 mV vs.Ag|AgCl) and also gave detection limits in the 10-7 M range for nitrite detection. L-cysteine was detected by the modified electrodes at potentials between 0.50 to 0.65 V vs.Ag|AgCl, with L-cysteine detection limits also in the 10-7 M range. The detection limits for melatonin ranged from 10-7 to 10-6 M. CoPc-modified electrodes displayed good separation of interferents (tryptophan and ascorbic acid) in the presence of melatonin. Analyses of commercial melatonin tablets using modified electrodes gave excellent agreement with manufacturer's value for all modified electrodes of this work.
- Full Text:
- Date Issued: 2009
On the evaluation of spectral effects on photovoltaic modules performance parameters and hotspots in solar cells
- Authors: Simon, Michael
- Date: 2009
- Subjects: Photovoltaic cells , Energy dissipation , Electric power production , Photovoltaic power generation , Solar energy , Spectral energy distribution
- Language: English
- Type: Thesis , Doctoral , PhD (Physics)
- Identifier: vital:11593 , http://hdl.handle.net/10353/257 , Photovoltaic cells , Energy dissipation , Electric power production , Photovoltaic power generation , Solar energy , Spectral energy distribution
- Description: The performance of photovoltaic (PV) modules in terms of their ability to convert incident photon to electrical energy (efficiency) depends mostly on the spectral distribution of incident radiation from the sun. The incident spectrum finally perceived by the module depends strongly on the composition of the medium in which it has traveled. The composition of the earth’s atmosphere, which includes, amongst others, water vapour, gases such as carbon dioxide and oxygen, absorbs or scatters some of the sunlight. The incident solar spectrum is also modified by the diffuse aspect of radiation from the sky which strongly depends on aerosol concentration, cloudiness and local reflection of the earth’s surface. Although it is well known that the changes in outdoor spectrum affect device performance, little work has been conducted to support this theory. This is probably due to lack of spectral data or in certain instances where data is available, little knowledge of interpreting that data. The outdoor spectral data that one obtains in the field does not come clearly for just simple interpretation. Different analytical interpretation procedures have been proposed, all trying to explain and quantify the spectral influence on PV devices. In this study an assessment methodology for evaluating the effects of outdoor spectra on device performance parameters during the course of the day, seasons and or cloudy cover has been developed. The methodology consists of developing a device dependant concept, Weighted Useful Fraction (WUF) using the outdoor measured spectral data. For measuring PV module’s performance parameters, a current-voltage (I-V) tester was developed in order to monitor the performance of six different module technologies. The Gaussian distribution was used to interpret the data. For hot-spot analysis, different techniques were used, which include Infrared thermographic technique for identifying the hot-spots in the solar cells, SEM and EDX techniques. The AES technique was also used in order to identify other elements at hot-spots sites that could not be detected by the EDX technique. iii Results obtained indicate that multicrystalline modules performance is affected by the changes in the outdoor spectrum during summer or winter seasons. The modules prefer a spectrum characterized by WUF = 0.809 during summer season. This spectrum corresponds to AM 2.19 which is different from AM 1.5 used for device ratings. In winter, the mc-Si module’s WUF (0.7125) peaks at 13h00 at a value corresponding to AM 1.83. Although these devices have a wider wavelength range, they respond differently in real outdoor environment. Results for mono – Si module showed that the device performs best at WUF = 0.6457 which corresponds to AM 1.83 during summer season, while it operates optimally under a winter spectrum indicated by WUF of 0.5691 (AM2.58). The seasonal changes resulted in the shift in WUF during day time corresponding to the “preferred” spectrum. This shift indicates that these devices should be rated using AM values that correspond to the WUF values under which the device operates optimally. For poly-Si, it was also observed the WUF values are lower than the other two crystalline-Si counterparts. The pc-Si was observed to prefer a lower AM value indicated by WUF = 0.5813 during winter season while for summer it prefers a spectrum characterized by WUF = 0.5541 at AM 3.36. The performance of the single junction a-Si module degraded by 67 percent after an initial outdoor exposure of 16 kWh/m² while the HIT module did not exhibit the initial degradation regardless of their similarities in material composition. It was established that the WUF before degradation peaks at 15h00 at a value of 0.7130 corresponding to AM 4.50 while the WUF after degradation “prefers” the spectrum (WUF = 0.6578) experienced at 15h30 corresponding to AM value of 5.57. Comparing the before and after degradation scenarios of a-Si:H, it was observed that the device spends less time under the red spectrum which implies that the device “prefers” a full spectrum to operate optimally. The degradation of a-Si:H device revealed that the device spectral response was also shifted by a 7.7 percent after degradation. A higher percentage difference (61.8 percent) for spectral range for the HIT module is observed, but with no effects on device parameters. Seasonal changes (summer/winter) resulted in the outdoor spectrum of CuInSe2 to vary by WUF = 1.5 percent, which resulted in the decrease in Isc. This was ascertained by iv analyzing the percentage change in WUF and evaluating the corresponding change in Isc. The analysis showed that there was a large percentage difference of the module’s Isc as the outdoor spectrum changed during the course of the day. This confirmed that the 17 percent decrease in Isc was due to a WUF of 1.5 percent. In mc-Si solar cells used in this study, it was found that elemental composition across the entire solar cell was not homogenously distributed resulting in high concentration of transition metals which were detected at hot spot areas. The presence of transition metals causes hot-spot formation in crystalline solar cells. Although several transition elements exist at hot-spot regions, the presence of oxygen, carbon, iron and platinum was detected in high concentrations. From this study, it is highly recommended that transition elements and oxygen must be minimized so as to increase the life expectancy of these devices and improve overall systems reliability
- Full Text:
- Date Issued: 2009
- Authors: Simon, Michael
- Date: 2009
- Subjects: Photovoltaic cells , Energy dissipation , Electric power production , Photovoltaic power generation , Solar energy , Spectral energy distribution
- Language: English
- Type: Thesis , Doctoral , PhD (Physics)
- Identifier: vital:11593 , http://hdl.handle.net/10353/257 , Photovoltaic cells , Energy dissipation , Electric power production , Photovoltaic power generation , Solar energy , Spectral energy distribution
- Description: The performance of photovoltaic (PV) modules in terms of their ability to convert incident photon to electrical energy (efficiency) depends mostly on the spectral distribution of incident radiation from the sun. The incident spectrum finally perceived by the module depends strongly on the composition of the medium in which it has traveled. The composition of the earth’s atmosphere, which includes, amongst others, water vapour, gases such as carbon dioxide and oxygen, absorbs or scatters some of the sunlight. The incident solar spectrum is also modified by the diffuse aspect of radiation from the sky which strongly depends on aerosol concentration, cloudiness and local reflection of the earth’s surface. Although it is well known that the changes in outdoor spectrum affect device performance, little work has been conducted to support this theory. This is probably due to lack of spectral data or in certain instances where data is available, little knowledge of interpreting that data. The outdoor spectral data that one obtains in the field does not come clearly for just simple interpretation. Different analytical interpretation procedures have been proposed, all trying to explain and quantify the spectral influence on PV devices. In this study an assessment methodology for evaluating the effects of outdoor spectra on device performance parameters during the course of the day, seasons and or cloudy cover has been developed. The methodology consists of developing a device dependant concept, Weighted Useful Fraction (WUF) using the outdoor measured spectral data. For measuring PV module’s performance parameters, a current-voltage (I-V) tester was developed in order to monitor the performance of six different module technologies. The Gaussian distribution was used to interpret the data. For hot-spot analysis, different techniques were used, which include Infrared thermographic technique for identifying the hot-spots in the solar cells, SEM and EDX techniques. The AES technique was also used in order to identify other elements at hot-spots sites that could not be detected by the EDX technique. iii Results obtained indicate that multicrystalline modules performance is affected by the changes in the outdoor spectrum during summer or winter seasons. The modules prefer a spectrum characterized by WUF = 0.809 during summer season. This spectrum corresponds to AM 2.19 which is different from AM 1.5 used for device ratings. In winter, the mc-Si module’s WUF (0.7125) peaks at 13h00 at a value corresponding to AM 1.83. Although these devices have a wider wavelength range, they respond differently in real outdoor environment. Results for mono – Si module showed that the device performs best at WUF = 0.6457 which corresponds to AM 1.83 during summer season, while it operates optimally under a winter spectrum indicated by WUF of 0.5691 (AM2.58). The seasonal changes resulted in the shift in WUF during day time corresponding to the “preferred” spectrum. This shift indicates that these devices should be rated using AM values that correspond to the WUF values under which the device operates optimally. For poly-Si, it was also observed the WUF values are lower than the other two crystalline-Si counterparts. The pc-Si was observed to prefer a lower AM value indicated by WUF = 0.5813 during winter season while for summer it prefers a spectrum characterized by WUF = 0.5541 at AM 3.36. The performance of the single junction a-Si module degraded by 67 percent after an initial outdoor exposure of 16 kWh/m² while the HIT module did not exhibit the initial degradation regardless of their similarities in material composition. It was established that the WUF before degradation peaks at 15h00 at a value of 0.7130 corresponding to AM 4.50 while the WUF after degradation “prefers” the spectrum (WUF = 0.6578) experienced at 15h30 corresponding to AM value of 5.57. Comparing the before and after degradation scenarios of a-Si:H, it was observed that the device spends less time under the red spectrum which implies that the device “prefers” a full spectrum to operate optimally. The degradation of a-Si:H device revealed that the device spectral response was also shifted by a 7.7 percent after degradation. A higher percentage difference (61.8 percent) for spectral range for the HIT module is observed, but with no effects on device parameters. Seasonal changes (summer/winter) resulted in the outdoor spectrum of CuInSe2 to vary by WUF = 1.5 percent, which resulted in the decrease in Isc. This was ascertained by iv analyzing the percentage change in WUF and evaluating the corresponding change in Isc. The analysis showed that there was a large percentage difference of the module’s Isc as the outdoor spectrum changed during the course of the day. This confirmed that the 17 percent decrease in Isc was due to a WUF of 1.5 percent. In mc-Si solar cells used in this study, it was found that elemental composition across the entire solar cell was not homogenously distributed resulting in high concentration of transition metals which were detected at hot spot areas. The presence of transition metals causes hot-spot formation in crystalline solar cells. Although several transition elements exist at hot-spot regions, the presence of oxygen, carbon, iron and platinum was detected in high concentrations. From this study, it is highly recommended that transition elements and oxygen must be minimized so as to increase the life expectancy of these devices and improve overall systems reliability
- Full Text:
- Date Issued: 2009
Evolutionary development and functional role of plant natriuretic peptide (PNP)-B
- Authors: Hove, Runyararo Memory
- Date: 2009
- Subjects: Plant hormones , Peptides , Plant gene expression , Peptide hormones , Peptides -- Separation
- Language: English
- Type: Thesis , Masters , MSc (Biochemistry)
- Identifier: vital:11251 , http://hdl.handle.net/10353/155 , Plant hormones , Peptides , Plant gene expression , Peptide hormones , Peptides -- Separation
- Description: Plant natriuretic peptides (PNP) are novel peptides which, like in vertebrates, have been shown to have a function associated with water and salt homeostasis. Two PNP-encoding genes have been identified and isolated from Arabidopsis thaliana, namely; AtPNP-A and AtPNP-B. In this study, the focus was on PNP-B, which has not been extensively studied. Bioinformatic analysis was done on the AtPNP-B gene. This included the bioinformatic study of its primary structure, secondary structure, tertiary structure, transcription factor binding sites (TFBS) and its relation to other known proteins. The AtPNP-B gene was shown to be a 510 bp long, including a predicted 138 bp intron. AtPNP-B was also shown to have some sequence similarity with AtPNP-A and CjBAp12. The TFBS for AtPNP-B and OsJPNP-B were compared and they comprised of TFBS that are related to water homeostasis and pathogenesis. This suggested two possible functions; water stress and homeostasis and a pathogenesis related function for PNP-B. Following bioinformatic analysis, the heterologous expression of the AtPNP-B was attempted to investigate whether the AtPNP-B gene encoded a functional protein and to determine the functional role of PNP-B. However, expression was unsuccessful. An evolutionary study was then carried out which revealed that there were some plants without the intron such as, rice, leafy spurge, oilseed rape, onion, poplar, sugar cane, sunflower and tobacco. These plants would therefore be used for expression and functional studies in the future. The evolutionary studies also revealed that PNP-B had a relationship with expansins and the endoglucanase family 45. Other PNP-B related molecules were also obtained from other plant genomes and therefore used in the construction of a phylogenetic tree. The phylogenetic tree revealed that AtPNP-B clustered in the same group as CjBAp12 while AtPNP-A had its own cluster group. There were also other PNP-B like molecules that clustered in the same group as expansins (α- and β-). Thus, we postulate that, like PNP-A, PNP-B also has a possible function in water and salt homeostasis. However, due to the clustering iii of AtPNP-B into the same group as CjBAp12, a possible role of PNP-B in pathogenesis-related response is also postulated.
- Full Text:
- Date Issued: 2009
- Authors: Hove, Runyararo Memory
- Date: 2009
- Subjects: Plant hormones , Peptides , Plant gene expression , Peptide hormones , Peptides -- Separation
- Language: English
- Type: Thesis , Masters , MSc (Biochemistry)
- Identifier: vital:11251 , http://hdl.handle.net/10353/155 , Plant hormones , Peptides , Plant gene expression , Peptide hormones , Peptides -- Separation
- Description: Plant natriuretic peptides (PNP) are novel peptides which, like in vertebrates, have been shown to have a function associated with water and salt homeostasis. Two PNP-encoding genes have been identified and isolated from Arabidopsis thaliana, namely; AtPNP-A and AtPNP-B. In this study, the focus was on PNP-B, which has not been extensively studied. Bioinformatic analysis was done on the AtPNP-B gene. This included the bioinformatic study of its primary structure, secondary structure, tertiary structure, transcription factor binding sites (TFBS) and its relation to other known proteins. The AtPNP-B gene was shown to be a 510 bp long, including a predicted 138 bp intron. AtPNP-B was also shown to have some sequence similarity with AtPNP-A and CjBAp12. The TFBS for AtPNP-B and OsJPNP-B were compared and they comprised of TFBS that are related to water homeostasis and pathogenesis. This suggested two possible functions; water stress and homeostasis and a pathogenesis related function for PNP-B. Following bioinformatic analysis, the heterologous expression of the AtPNP-B was attempted to investigate whether the AtPNP-B gene encoded a functional protein and to determine the functional role of PNP-B. However, expression was unsuccessful. An evolutionary study was then carried out which revealed that there were some plants without the intron such as, rice, leafy spurge, oilseed rape, onion, poplar, sugar cane, sunflower and tobacco. These plants would therefore be used for expression and functional studies in the future. The evolutionary studies also revealed that PNP-B had a relationship with expansins and the endoglucanase family 45. Other PNP-B related molecules were also obtained from other plant genomes and therefore used in the construction of a phylogenetic tree. The phylogenetic tree revealed that AtPNP-B clustered in the same group as CjBAp12 while AtPNP-A had its own cluster group. There were also other PNP-B like molecules that clustered in the same group as expansins (α- and β-). Thus, we postulate that, like PNP-A, PNP-B also has a possible function in water and salt homeostasis. However, due to the clustering iii of AtPNP-B into the same group as CjBAp12, a possible role of PNP-B in pathogenesis-related response is also postulated.
- Full Text:
- Date Issued: 2009
Interpretation of regional geochemical data as an aid to exploration target generation in the North West Province South Africa
- Authors: Mapukule, Livhuwani Ernest
- Date: 2009
- Subjects: Ore deposits -- South Africa , Prospecting -- South Africa , Mines and mineral resources -- South Africa
- Language: English
- Type: Thesis , Masters , MSc (Geology)
- Identifier: vital:11519 , http://hdl.handle.net/10353/268 , Ore deposits -- South Africa , Prospecting -- South Africa , Mines and mineral resources -- South Africa
- Description: This study involves the application, interpretation and utilization of regional geochemical data for target generation in the North West Province, South Africa. A regional soil geochemical survey programme has been carried out by the Council of Geoscience South Africa since 1973. A number of 1:250 000 sheet areas have been completed, but there are no interpretative maps which could aid in mineral exploration and other purposes. In order to utilize the valuable and expensive data, the project was motivated through data acquisition and interpretation to generate exploration targets. The study area is confined to Mafikeng, Vryburg, Kuruman and Christiana in the Northwest Province, where potential exploration and mining opportunities exist in areas of great geological interest. These include geological events such as the Bushveld Complex, the Kalahari manganese field and the Kraaipan greenstone belts. The aim of this project was to utilize geochemical data together with geophysical and geological information to verify and identification of possible obscured ore bodies or zones of mineralization, and to generate targets. Another objective was the author to be trained in the techniques of geochemical data processing, interpretation and integration of techniques such as geophysics, in the understanding of the geology and economic geology of the areas. Approximately 5 kg of surface soil was collected per 1 km2 by CGS from foot traversing. Pellets of the samples were prepared and analyzed for TiO2, MnO and Fe2O3, Sc, V, Cr, Ni, Co, Cu, Zn, As, Y, Ba, Nb, Rb, Th, W, Zr, Pb, Sr and U using the simultaneous wavelengthdispersive X-ray fluorescence spectrometer technique at the Council for Geoscience, South Africa. For each element the mean +2 standard deviations were used as a threshold value to separate the negative from the positive anomalies. The integration of geological, geophysical and geochemical information was used to analyze and understand the areas of interest. A number of computer programmes were extensively used for data processing, manipulation, and presentation. These include Golden Software Surfer 8®, Arc-View 3.2a®, TNT-Mips®, JMP 8 ®, and Microsoft Excel®. Through geochemical data processing and interpretation, together with the low resolution aeromagnetic data, gravity data and geological data, seven (7) exploration target areas have been generated: These have been numbered A to G. It is concluded that there is good potential for Cr, PGMs, vanadium, nickel, iron, copper, manganese, uranium and niobium in the targets generated. The results provide some indication and guide for exploration in the target areas. In Target A, Cu, Cr, Fe, Ni and V anomalies from the lower chromitite zone of far western zone of the Bushveld Complex, which has be overlain buy the thick surface sand of the Gordonia Formation. Target B occurs over the diabase, norite, andesitic lava and andalusite muscovite hornfels of the Magaliesberg Formation. This target has the potential for Cu, Fe and Ni mineralization. The felsic rocks of the Kanye Formation and the Gaborone Granite in target C have shown some positive anomalies of niobium, uranium, yttrium and rubidium which give the area potential for Nb, REE and U exploration. Target D is located on the Allanridge Formation, and has significant potential for Ni-Cu mineralization, and is associated with the komatiitic lava at the base of the Allanridge Formation in the Christiana Area. The light green tholeiitic, calc-alkali basalt and andesitic rocks of the Rietgat Formation are characterized by a north-south trending yttrium anomaly with supporting Ba and Y anomalies (Target E). This makes the area a potential target for rare earth elements. Calcrete on the west of the Kuruman has a low b potential target for vanadium. It is believed that the area might be potential for potassium-uranium vanadate minerals, carnotite which is mostly found in calcrete deposits. This study has proved to be a useful and approach in utilizing the valuable geochemical data for exploration and future mining, generated by Council for Geoscience Science. It is recommended that further detailed soil, rock and geochemical surveys and ultimately diamond drilling be carried out in the exploration target areas generated by this study.
- Full Text:
- Date Issued: 2009
- Authors: Mapukule, Livhuwani Ernest
- Date: 2009
- Subjects: Ore deposits -- South Africa , Prospecting -- South Africa , Mines and mineral resources -- South Africa
- Language: English
- Type: Thesis , Masters , MSc (Geology)
- Identifier: vital:11519 , http://hdl.handle.net/10353/268 , Ore deposits -- South Africa , Prospecting -- South Africa , Mines and mineral resources -- South Africa
- Description: This study involves the application, interpretation and utilization of regional geochemical data for target generation in the North West Province, South Africa. A regional soil geochemical survey programme has been carried out by the Council of Geoscience South Africa since 1973. A number of 1:250 000 sheet areas have been completed, but there are no interpretative maps which could aid in mineral exploration and other purposes. In order to utilize the valuable and expensive data, the project was motivated through data acquisition and interpretation to generate exploration targets. The study area is confined to Mafikeng, Vryburg, Kuruman and Christiana in the Northwest Province, where potential exploration and mining opportunities exist in areas of great geological interest. These include geological events such as the Bushveld Complex, the Kalahari manganese field and the Kraaipan greenstone belts. The aim of this project was to utilize geochemical data together with geophysical and geological information to verify and identification of possible obscured ore bodies or zones of mineralization, and to generate targets. Another objective was the author to be trained in the techniques of geochemical data processing, interpretation and integration of techniques such as geophysics, in the understanding of the geology and economic geology of the areas. Approximately 5 kg of surface soil was collected per 1 km2 by CGS from foot traversing. Pellets of the samples were prepared and analyzed for TiO2, MnO and Fe2O3, Sc, V, Cr, Ni, Co, Cu, Zn, As, Y, Ba, Nb, Rb, Th, W, Zr, Pb, Sr and U using the simultaneous wavelengthdispersive X-ray fluorescence spectrometer technique at the Council for Geoscience, South Africa. For each element the mean +2 standard deviations were used as a threshold value to separate the negative from the positive anomalies. The integration of geological, geophysical and geochemical information was used to analyze and understand the areas of interest. A number of computer programmes were extensively used for data processing, manipulation, and presentation. These include Golden Software Surfer 8®, Arc-View 3.2a®, TNT-Mips®, JMP 8 ®, and Microsoft Excel®. Through geochemical data processing and interpretation, together with the low resolution aeromagnetic data, gravity data and geological data, seven (7) exploration target areas have been generated: These have been numbered A to G. It is concluded that there is good potential for Cr, PGMs, vanadium, nickel, iron, copper, manganese, uranium and niobium in the targets generated. The results provide some indication and guide for exploration in the target areas. In Target A, Cu, Cr, Fe, Ni and V anomalies from the lower chromitite zone of far western zone of the Bushveld Complex, which has be overlain buy the thick surface sand of the Gordonia Formation. Target B occurs over the diabase, norite, andesitic lava and andalusite muscovite hornfels of the Magaliesberg Formation. This target has the potential for Cu, Fe and Ni mineralization. The felsic rocks of the Kanye Formation and the Gaborone Granite in target C have shown some positive anomalies of niobium, uranium, yttrium and rubidium which give the area potential for Nb, REE and U exploration. Target D is located on the Allanridge Formation, and has significant potential for Ni-Cu mineralization, and is associated with the komatiitic lava at the base of the Allanridge Formation in the Christiana Area. The light green tholeiitic, calc-alkali basalt and andesitic rocks of the Rietgat Formation are characterized by a north-south trending yttrium anomaly with supporting Ba and Y anomalies (Target E). This makes the area a potential target for rare earth elements. Calcrete on the west of the Kuruman has a low b potential target for vanadium. It is believed that the area might be potential for potassium-uranium vanadate minerals, carnotite which is mostly found in calcrete deposits. This study has proved to be a useful and approach in utilizing the valuable geochemical data for exploration and future mining, generated by Council for Geoscience Science. It is recommended that further detailed soil, rock and geochemical surveys and ultimately diamond drilling be carried out in the exploration target areas generated by this study.
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- Date Issued: 2009