The use of an analogy in conjunction with a conventional practical activity to mediate Grade 11 learners’ sense making of Ohm’s law
- Authors: Ramasike, Lineo Florence
- Date: 2017
- Subjects: Physical sciences -- Study and teaching (Secondary) -- South Africa Ohm's law Academic achievement
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/4558 , vital:20689
- Description: In most South African schools Grade 12 Physical Sciences learners are generally not performing well. As Examiners’ Reports reveal, they are particularly weak on the topic of electrical circuits. Because of this, the Examiners recommended that conventional practical activities and revision should be implemented to improve learners’ performance whilst they are in Grade 11. These factors contributed to the rationale of this study in using the ‘straw electricity’ analogy in conjunction with a conventional practical activity to mediate learners’ sense making of Ohm’s law. The study falls within the interpretive paradigm, whose focus is on the understanding of human world-views. Within the interpretive paradigm a qualitative case study approach was employed. It is a case study because it aimed to investigate a group of learners in a given context. This qualitative case study used purposive sampling to select participants. Various data gathering techniques were employed, namely, documents, observations and stimulated recall interviews. The gathered data was analysed so as to determine the indicators of how learners made sense of Ohm’s law. The findings of this study are that learners were able to construct new knowledge within a social context where the ‘straw electricity’ analogy, using easily accessible resources, was incorporated in tandem with a conventional practical classroom task. Moreover, the ‘straw electricity’ analogy enabled a better understanding of science concepts as it tested and supported different learning skills.
- Full Text:
- Date Issued: 2017
- Authors: Ramasike, Lineo Florence
- Date: 2017
- Subjects: Physical sciences -- Study and teaching (Secondary) -- South Africa Ohm's law Academic achievement
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/4558 , vital:20689
- Description: In most South African schools Grade 12 Physical Sciences learners are generally not performing well. As Examiners’ Reports reveal, they are particularly weak on the topic of electrical circuits. Because of this, the Examiners recommended that conventional practical activities and revision should be implemented to improve learners’ performance whilst they are in Grade 11. These factors contributed to the rationale of this study in using the ‘straw electricity’ analogy in conjunction with a conventional practical activity to mediate learners’ sense making of Ohm’s law. The study falls within the interpretive paradigm, whose focus is on the understanding of human world-views. Within the interpretive paradigm a qualitative case study approach was employed. It is a case study because it aimed to investigate a group of learners in a given context. This qualitative case study used purposive sampling to select participants. Various data gathering techniques were employed, namely, documents, observations and stimulated recall interviews. The gathered data was analysed so as to determine the indicators of how learners made sense of Ohm’s law. The findings of this study are that learners were able to construct new knowledge within a social context where the ‘straw electricity’ analogy, using easily accessible resources, was incorporated in tandem with a conventional practical classroom task. Moreover, the ‘straw electricity’ analogy enabled a better understanding of science concepts as it tested and supported different learning skills.
- Full Text:
- Date Issued: 2017
The use of behaviour, saliva cortisol and faecal glucocorticoid levels as stress indicators in beef cows
- Authors: Dzviti, Melody
- Date: 2017
- Subjects: Veterinary physiology Beef cattle -- Behavior Glucocorticoids
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8165 , vital:31634
- Description: The study evaluated the use of saliva as a minimally invasive technique for cortisol level determination. This was done by assessing the relationship between serum and saliva cortisol based on short sampling intervals. In addition, the study also determined the effect of successive handling on faecal glucocorticoid metabolites (FGM), rectal temperature (RT), avoidance distance (AD), chute and crush scores as well as urination, defaecation and vocalization in multiparous cows. For trial one six non-pregnant, clinically healthy Nguni cows were used. They were administered with standardised doses of adrenocorticotropic hormone on treatment days and saline was used as a placebo on alternative days. Simultaneously, blood and saliva samples were collected to quantify cortisol levels. No relationship (r = 0.0131, P>0.05) was observed between serum and saliva cortisol. However, results showed that there was adrenal stimulation in saliva coupled by significant (P<0.05) effects of sampling intervals. For the second study 21 non-pregnant and clinically healthy Nguni cows of one herd were used for the trial. They were divided into parity groups and their weights were used as a covariate in data analysis. For five consecutive weeks, fresh faecal samples were extracted and rectal temperatures measured. In addition, fear of approaching humans was assessed by AD scores and behaviour scores in the crush chute, as well as vocalisation, urination and defaecation were observed. The effect of successive handling significantly (P<0.05) affected the physiological parameters, namely FGM and RT. Contrariwise, Chi-square tests revealed that parities had a significant (χ2 < 0.05) influence on AD and crush scores as well as on the occurrence of excretory behaviour. It was concluded that saliva cortisol can be used as a stress indicator in beef cows. However, plasma cortisol can be significantly volatile thereby becoming less sensitive to changes across time. This can cause a lack of relationship between plasma and saliva cortisol. On the other hand, repetitive handling of beef cows has an influence on faecal stress levels. In addition, beef cows of differing parities behave differently to handling stress.
- Full Text:
- Date Issued: 2017
- Authors: Dzviti, Melody
- Date: 2017
- Subjects: Veterinary physiology Beef cattle -- Behavior Glucocorticoids
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8165 , vital:31634
- Description: The study evaluated the use of saliva as a minimally invasive technique for cortisol level determination. This was done by assessing the relationship between serum and saliva cortisol based on short sampling intervals. In addition, the study also determined the effect of successive handling on faecal glucocorticoid metabolites (FGM), rectal temperature (RT), avoidance distance (AD), chute and crush scores as well as urination, defaecation and vocalization in multiparous cows. For trial one six non-pregnant, clinically healthy Nguni cows were used. They were administered with standardised doses of adrenocorticotropic hormone on treatment days and saline was used as a placebo on alternative days. Simultaneously, blood and saliva samples were collected to quantify cortisol levels. No relationship (r = 0.0131, P>0.05) was observed between serum and saliva cortisol. However, results showed that there was adrenal stimulation in saliva coupled by significant (P<0.05) effects of sampling intervals. For the second study 21 non-pregnant and clinically healthy Nguni cows of one herd were used for the trial. They were divided into parity groups and their weights were used as a covariate in data analysis. For five consecutive weeks, fresh faecal samples were extracted and rectal temperatures measured. In addition, fear of approaching humans was assessed by AD scores and behaviour scores in the crush chute, as well as vocalisation, urination and defaecation were observed. The effect of successive handling significantly (P<0.05) affected the physiological parameters, namely FGM and RT. Contrariwise, Chi-square tests revealed that parities had a significant (χ2 < 0.05) influence on AD and crush scores as well as on the occurrence of excretory behaviour. It was concluded that saliva cortisol can be used as a stress indicator in beef cows. However, plasma cortisol can be significantly volatile thereby becoming less sensitive to changes across time. This can cause a lack of relationship between plasma and saliva cortisol. On the other hand, repetitive handling of beef cows has an influence on faecal stress levels. In addition, beef cows of differing parities behave differently to handling stress.
- Full Text:
- Date Issued: 2017
The use of competitive intelligence in the sustainability of SMMEs in the Buffalo City Metropolitan Municipality (BCMM)
- Authors: Fakir, Kiran
- Date: 2017
- Subjects: Business intelligence -- South Africa -- East London Business enterprises -- South Africa -- East London , Small business -- South Africa -- East London
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/15182 , vital:28176
- Description: The Buffalo City Metropolitan Municipality (BCMM), situated in the second largest province in South Africa, the Eastern Cape, is an unfortunate victim of low economic development and high unemployment. The South African Government, through the Department of Trade and Industry, identified the need for SMMEs to address these issues with the inception of the White Paper on National Strategy for the Development and Promotion of Small Business in South Africa over 20 years ago. SMMEs in South Africa are noted to have a failure rate of around 70% which does not bode well for the efforts to improve economic development and reduce unemployment through SMMEs. This research sets out to determine the significance of variables such as human resources, financial resources, information systems, government assistance and competitive intelligence on the sustainability of SMMEs. The researcher examined the literature relating to the challenges and issues faced by SMMEs with particular emphasis on the use of competitive intelligence as a tool to assist in sustainability. The literature review was followed by an analysis and interpretation of a qualitative study of SMMEs within the BCMM. Through an analysis of the results it was possible to determine the nature of the relationships between the independent variables and sustainability. Finally, the researcher was able to make recommendations based on the research.
- Full Text:
- Date Issued: 2017
- Authors: Fakir, Kiran
- Date: 2017
- Subjects: Business intelligence -- South Africa -- East London Business enterprises -- South Africa -- East London , Small business -- South Africa -- East London
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/15182 , vital:28176
- Description: The Buffalo City Metropolitan Municipality (BCMM), situated in the second largest province in South Africa, the Eastern Cape, is an unfortunate victim of low economic development and high unemployment. The South African Government, through the Department of Trade and Industry, identified the need for SMMEs to address these issues with the inception of the White Paper on National Strategy for the Development and Promotion of Small Business in South Africa over 20 years ago. SMMEs in South Africa are noted to have a failure rate of around 70% which does not bode well for the efforts to improve economic development and reduce unemployment through SMMEs. This research sets out to determine the significance of variables such as human resources, financial resources, information systems, government assistance and competitive intelligence on the sustainability of SMMEs. The researcher examined the literature relating to the challenges and issues faced by SMMEs with particular emphasis on the use of competitive intelligence as a tool to assist in sustainability. The literature review was followed by an analysis and interpretation of a qualitative study of SMMEs within the BCMM. Through an analysis of the results it was possible to determine the nature of the relationships between the independent variables and sustainability. Finally, the researcher was able to make recommendations based on the research.
- Full Text:
- Date Issued: 2017
The use of enterprise resource planning systems in three leading bakeries in South Africa
- Authors: Mokuena, Mpolokeng
- Date: 2017
- Subjects: Enterprise resource planning -- South Africa Business planning -- South Africa , Management information systems -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/19157 , vital:28778
- Description: There is a continued effort for organisations to invest in resources that enable them to reduce costs while increasing productivity to meet the needs of the customers in order to maximise profits. Such investments also empower them to gain competitive advantage in the market. In an endeavour to achieve this, organisations invest in implementing Information Technology (IT) software to assist in increasing efficiency. There are varieties of available software solutions that are used at various stages of the value-chain. One of these is the Enterprise Resource Planning (ERP) system. Bakeries are no exception in exploring ways in which operations can be run more efficiently to reduce costs in the various levels of the supply chain through use of ERP systems. Although bakeries have invested many funds in implementing this system, they fail to enjoy the full returns on their investment of this system. The study compares the use of ERP systems between three leading bakers in Port Elizabeth, as part of convenience sampling, to identify any possible ineffective business practice applications and recommend some applicable solutions. In pursuing this study, a qualitative research was conducted. A critical literature review drawing on academic sources was conducted on the Supply Chain Management SCM. It provides an overview of SCM, and the effectiveness of ERP is SCM. Additionally, it provides benefits of using ERP in SCM. Furthermore, various tools that are used in measuring effectiveness of ERP systems were discussed. These tools included, Perceived Ease of Use and Perceived Usefulness, part of the Technology Acceptance Model (TAM) and the balanced scored card. This was followed by a content analysis of web-based content of the three bakeries. Interview schedules were conducted using close-ended and open-ended questionnaires with the procurement, production, and distribution officers in the three bakeries to get a deeper understanding of the experience of the respondents. The questionnaires were distributed to twenty-seven (27) potential participants but interviews were conducted with only five (5) respondents. This constitutes a (5/27) 18.5% response rate. The questions on the questionnaires required a deeper understanding of the experiences of the respondents on their use of ERP. The questions were adopted from a balanced score card questionnaire that was previously used in measuring the performance of ERP systems.The study used Perceived Usefulness and Perceived Ease of Use within the Technology Acceptance Model (TAM) to measure the effectiveness of ERP systems that are used in bakeries The analysis revealed that some production departments did not use the ERP system altogether while others used it as an archive and stuck to manual tasks resulting in duplication of tasks, which increase the workload of the departments. It also discourages interdepartmental information integration because other departments do not have easy and quick access to information from their production department. This department must share information to other departments through email. It was discovered that some end-users do not undergo formal training that affect their use of the system making it ineffective. Some found that their system was not user-friendly and increased their workload. Recommendations are made to the management of the bakeries on how to make the use of ERP effective for those planning to upgrade their current baking management systems.
- Full Text:
- Date Issued: 2017
- Authors: Mokuena, Mpolokeng
- Date: 2017
- Subjects: Enterprise resource planning -- South Africa Business planning -- South Africa , Management information systems -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/19157 , vital:28778
- Description: There is a continued effort for organisations to invest in resources that enable them to reduce costs while increasing productivity to meet the needs of the customers in order to maximise profits. Such investments also empower them to gain competitive advantage in the market. In an endeavour to achieve this, organisations invest in implementing Information Technology (IT) software to assist in increasing efficiency. There are varieties of available software solutions that are used at various stages of the value-chain. One of these is the Enterprise Resource Planning (ERP) system. Bakeries are no exception in exploring ways in which operations can be run more efficiently to reduce costs in the various levels of the supply chain through use of ERP systems. Although bakeries have invested many funds in implementing this system, they fail to enjoy the full returns on their investment of this system. The study compares the use of ERP systems between three leading bakers in Port Elizabeth, as part of convenience sampling, to identify any possible ineffective business practice applications and recommend some applicable solutions. In pursuing this study, a qualitative research was conducted. A critical literature review drawing on academic sources was conducted on the Supply Chain Management SCM. It provides an overview of SCM, and the effectiveness of ERP is SCM. Additionally, it provides benefits of using ERP in SCM. Furthermore, various tools that are used in measuring effectiveness of ERP systems were discussed. These tools included, Perceived Ease of Use and Perceived Usefulness, part of the Technology Acceptance Model (TAM) and the balanced scored card. This was followed by a content analysis of web-based content of the three bakeries. Interview schedules were conducted using close-ended and open-ended questionnaires with the procurement, production, and distribution officers in the three bakeries to get a deeper understanding of the experience of the respondents. The questionnaires were distributed to twenty-seven (27) potential participants but interviews were conducted with only five (5) respondents. This constitutes a (5/27) 18.5% response rate. The questions on the questionnaires required a deeper understanding of the experiences of the respondents on their use of ERP. The questions were adopted from a balanced score card questionnaire that was previously used in measuring the performance of ERP systems.The study used Perceived Usefulness and Perceived Ease of Use within the Technology Acceptance Model (TAM) to measure the effectiveness of ERP systems that are used in bakeries The analysis revealed that some production departments did not use the ERP system altogether while others used it as an archive and stuck to manual tasks resulting in duplication of tasks, which increase the workload of the departments. It also discourages interdepartmental information integration because other departments do not have easy and quick access to information from their production department. This department must share information to other departments through email. It was discovered that some end-users do not undergo formal training that affect their use of the system making it ineffective. Some found that their system was not user-friendly and increased their workload. Recommendations are made to the management of the bakeries on how to make the use of ERP effective for those planning to upgrade their current baking management systems.
- Full Text:
- Date Issued: 2017
The use of experimental design for the development of a capillary zone electrophoresis method for the quantitation of captopril
- Mukozhiwa, S Y, Khamanga, Sandile M, Walker, Roderick B
- Authors: Mukozhiwa, S Y , Khamanga, Sandile M , Walker, Roderick B
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183828 , vital:44073 , xlink:href="https://doi.org/10.1691/ph.2017.7071"
- Description: A capillary zone electrophoresis (CZE) method for the quantitation of captopril (CPT) using UV detection was developed. Influence of electrolyte concentration and system variables on electrophoretic separation was evaluated and a central composite design (CCD) was used to optimize the method. Variables investigated were pH, molarity, applied voltage and capillary length. The influence of sodium metabisulphite on the stability of test solutions was also investigated. The use of sodium metabisulphite prevented degradation of CPT over 24 hours. A fused uncoated silica capillary of 67.5cm total and 57.5 cm effective length was used for analysis. The applied voltage and capillary length affected the migration time of CPT significantly. A 20 mM phosphate buffer adjusted to pH 7.0 was used as running buffer and an applied voltage of 23.90 kV was suitable to effect a separation. The optimized electrophoretic conditions produced sharp, well-resolved peaks for CPT and sodium metabisulphite. Linear regression analysis of the response for CPT standards revealed the method was linear (R2 = 0.9995) over the range 5-70 μg/mL. The limits of quantitation and detection were 5 and 1.5 μg/mL. A simple, rapid and reliable CZE method has been developed and successfully applied to the analysis of commercially available CPT products.
- Full Text:
- Date Issued: 2017
- Authors: Mukozhiwa, S Y , Khamanga, Sandile M , Walker, Roderick B
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183828 , vital:44073 , xlink:href="https://doi.org/10.1691/ph.2017.7071"
- Description: A capillary zone electrophoresis (CZE) method for the quantitation of captopril (CPT) using UV detection was developed. Influence of electrolyte concentration and system variables on electrophoretic separation was evaluated and a central composite design (CCD) was used to optimize the method. Variables investigated were pH, molarity, applied voltage and capillary length. The influence of sodium metabisulphite on the stability of test solutions was also investigated. The use of sodium metabisulphite prevented degradation of CPT over 24 hours. A fused uncoated silica capillary of 67.5cm total and 57.5 cm effective length was used for analysis. The applied voltage and capillary length affected the migration time of CPT significantly. A 20 mM phosphate buffer adjusted to pH 7.0 was used as running buffer and an applied voltage of 23.90 kV was suitable to effect a separation. The optimized electrophoretic conditions produced sharp, well-resolved peaks for CPT and sodium metabisulphite. Linear regression analysis of the response for CPT standards revealed the method was linear (R2 = 0.9995) over the range 5-70 μg/mL. The limits of quantitation and detection were 5 and 1.5 μg/mL. A simple, rapid and reliable CZE method has been developed and successfully applied to the analysis of commercially available CPT products.
- Full Text:
- Date Issued: 2017
The use of herbicides for the management of Eucalyptus coppice in South Africa
- Authors: Roberts, Jonathan Cecil
- Date: 2017
- Subjects: Eucalyptus grandis -- South Africa Herbicides -- South Africa
- Language: English
- Type: Thesis , Masters , Degree
- Identifier: http://hdl.handle.net/10948/20287 , vital:29205
- Description: The effectiveness and relatively low cost of herbicides has led to the near exclusion of non-herbicide methods for controlling weeds in commercial forestry plantations. However, any herbicide used within the forestry context has the potential to be toxic and/or alter ecosystem dynamics. In response to increased public concern, perceptions of risk, and compliance associated with forest certification standards and criterion, there is an increased need to provide alternative methods that can reduce reliance on herbicides. Even though adequate research has been implemented regarding herbicide use, little research has examined the implications of herbicide use or non-use throughout the full rotation. Since herbicide use is integrated within the management of eucalypt regeneration, it is critical that a comprehensive understanding of herbicide use be obtained before informed management decisions can be made. Only once this has been obtained, can reduced and judicious recourse to herbicide use be considered, both within the requirements of certification criteria and of good management practice (economic and site sustainability). The main objective of this thesis was to increase the understanding of herbicide use, as well the cost involved within the context of eucalypt coppice regimes in South Africa. Three field trials (two rotation-end, and one short-term) were implemented to achieve this objective, with herbicide use aimed at either killing eucalypt stumps if replanting, or control of secondary coppice regrowth if coppicing. The first trial was situated in Mpumalanga and evaluated which method of control would be best suited to reducing cost (cost-effective) and reliance on herbicides for killing eucalypt stumps and control of resulting coppice regrowth. Selected cut-stump and basal-frill treatments were included with triclopyr (480 g L-1 a.i.) applied to the cambium of difficult-to-kill Eucalyptus macarthurii H. Deane & Maiden stumps that had previously been coppiced multiple times. The resulting coppice regrowth was either manually removed, or glyphosate (360 g L-1 a.i.) applied to foliage. These treatments were integrated with non-chemical control methods, where E. dunnii Maiden seedlings were planted either between each stump row or within the row, to determine whether such treatments could further reduce the level of coppicing through shading. At rotation end, the different treatments tested had no significant influence on any of the E. dunnii growth variates. As there were no significant differences, the treatment with the lowest overall cost and herbicide used would be preferred. The application of triclopyr to the cut-surface following felling was the most cost-effective treatment. The differences in cost obtained is directly related to required follow-up coppice regrowth control operations and quantity of total herbicide applied (both triclopyr and glyphosate). It was hoped that the non-chemical control method (planting position of seedlings) would reduce the level of coppicing, however, within this trial, this did not occur. The second trial was situated in Zululand on Eucalyptus grandis x E. urophylla coppice that investigated different methods to control secondary coppice regrowth through either manual removal with a bush-knife, or the application of glyphosate (360 g L-1 a.i.) to the foliage. A range of herbicide rates (0.6%, 1.2% and 1.8%) was applied to the foliage of the secondary coppice regrowth when it reached a predetermined mean height (0.5 m, 1.0 m and 1.5 m). The objective was to determine the optimum rate and timing of control and to avoid glyphosate from being over-applied when managing this regrowth. No significant differences were detected between the different treatments for any of the growth variates at rotation end. The use of glyphosate, irrespective of rate and/or timing of application (as assessed by secondary coppice regrowth height) proved to be more cost-effective compared to manual removal of secondary coppice regrowth. Treatment efficacy in terms of treating secondary coppice regrowth increased with an increase in the rate of glyphosate applied (0% < 0.6% < 1.2% < 1 .8%), especially when treated at either 1.0 or 1.5 m in height. Although the volume of the glyphosate used increased with increasing secondary coppice regrowth height (0.5 m < 1.0 m < 1.5 m) due to the larger foliar spraying area, there was little difference in total glyphosate used when comparing the same herbicide rate across the three different heights. The most cost-effective treatment was that where glyphosate was applied at 1.2% when the secondary coppice regrowth was 1-1.5 m. The third trial (also located in Zululand on Eucalyptus grandis x E. urophylla) was implemented to test the knowledge gained in trial two, thereby determinng coppice management regimes that would facilitate mechanised harvesting. In this trial, coppice shoots were reduced to one stem per stump in one thinning operation (coppice reduction heights of 3.5 m, 4.5 m and 6.5 m), with the impact of increased secondary coppice regrowth monitored together with the testing of different control methods. An additional control treatment was included (current best operating practice) with coppice shoots thinned to two stems per stump at shoot height of 3.5 m, and thereafter to original stocking at stem height of 6.5 m. Herbicide rate and timing of application was based on the results obtained in the second trial, with glyphosate applied at 1.2% when the secondary coppice regrowth reached a mean height of approximately 1 m. At the final measurement date, the diameter at breast height for all three coppice reduction height treatments (3.5 m, 4.5 m and 6.5 m) were significantly larger than the additional control treatment. This can be attributed to the allocation of resources to the remaining stem at an earlier age, resulting in a growth benefit. For stocking, the 6.5 m coppice reduction height was significantly higher compared to both the 3.5 m and 4.5 m coppice reduction treatments, while not significantly different from the additional control. In this trial, secondary coppice regrowth had no effect on tree growth. Due to the short duration of this trial, a longer trial period would be necessary to obtain a full understanding of the impacts of the various coppice reduction treatments, and the resulting secondary coppice regrowth influence on selected coppice growth if left untreated. As several previous studies have shown the importance of controlling secondary coppice regrowth, it is recommended not to view the results of this present trial in isolation. On the basis of the results of this research, it can be concluded that the control of coppice regrowth with herbicides is more effective than any of the manual removal treatments in terms of cost, with manual control requiring more follow-up control operations. Even though the manual removal of coppice regrowth had no influence on growth of the remaining stems or planted trees, the potential injury to labourers or growing stock is still of concern. Therefore, the use of herbicides for controlling coppice regrowth would be preferable. However, if reduced herbicide-use is a major criterion, then coppice regrowth can be controlled manually, although at a higher cost.
- Full Text:
- Date Issued: 2017
- Authors: Roberts, Jonathan Cecil
- Date: 2017
- Subjects: Eucalyptus grandis -- South Africa Herbicides -- South Africa
- Language: English
- Type: Thesis , Masters , Degree
- Identifier: http://hdl.handle.net/10948/20287 , vital:29205
- Description: The effectiveness and relatively low cost of herbicides has led to the near exclusion of non-herbicide methods for controlling weeds in commercial forestry plantations. However, any herbicide used within the forestry context has the potential to be toxic and/or alter ecosystem dynamics. In response to increased public concern, perceptions of risk, and compliance associated with forest certification standards and criterion, there is an increased need to provide alternative methods that can reduce reliance on herbicides. Even though adequate research has been implemented regarding herbicide use, little research has examined the implications of herbicide use or non-use throughout the full rotation. Since herbicide use is integrated within the management of eucalypt regeneration, it is critical that a comprehensive understanding of herbicide use be obtained before informed management decisions can be made. Only once this has been obtained, can reduced and judicious recourse to herbicide use be considered, both within the requirements of certification criteria and of good management practice (economic and site sustainability). The main objective of this thesis was to increase the understanding of herbicide use, as well the cost involved within the context of eucalypt coppice regimes in South Africa. Three field trials (two rotation-end, and one short-term) were implemented to achieve this objective, with herbicide use aimed at either killing eucalypt stumps if replanting, or control of secondary coppice regrowth if coppicing. The first trial was situated in Mpumalanga and evaluated which method of control would be best suited to reducing cost (cost-effective) and reliance on herbicides for killing eucalypt stumps and control of resulting coppice regrowth. Selected cut-stump and basal-frill treatments were included with triclopyr (480 g L-1 a.i.) applied to the cambium of difficult-to-kill Eucalyptus macarthurii H. Deane & Maiden stumps that had previously been coppiced multiple times. The resulting coppice regrowth was either manually removed, or glyphosate (360 g L-1 a.i.) applied to foliage. These treatments were integrated with non-chemical control methods, where E. dunnii Maiden seedlings were planted either between each stump row or within the row, to determine whether such treatments could further reduce the level of coppicing through shading. At rotation end, the different treatments tested had no significant influence on any of the E. dunnii growth variates. As there were no significant differences, the treatment with the lowest overall cost and herbicide used would be preferred. The application of triclopyr to the cut-surface following felling was the most cost-effective treatment. The differences in cost obtained is directly related to required follow-up coppice regrowth control operations and quantity of total herbicide applied (both triclopyr and glyphosate). It was hoped that the non-chemical control method (planting position of seedlings) would reduce the level of coppicing, however, within this trial, this did not occur. The second trial was situated in Zululand on Eucalyptus grandis x E. urophylla coppice that investigated different methods to control secondary coppice regrowth through either manual removal with a bush-knife, or the application of glyphosate (360 g L-1 a.i.) to the foliage. A range of herbicide rates (0.6%, 1.2% and 1.8%) was applied to the foliage of the secondary coppice regrowth when it reached a predetermined mean height (0.5 m, 1.0 m and 1.5 m). The objective was to determine the optimum rate and timing of control and to avoid glyphosate from being over-applied when managing this regrowth. No significant differences were detected between the different treatments for any of the growth variates at rotation end. The use of glyphosate, irrespective of rate and/or timing of application (as assessed by secondary coppice regrowth height) proved to be more cost-effective compared to manual removal of secondary coppice regrowth. Treatment efficacy in terms of treating secondary coppice regrowth increased with an increase in the rate of glyphosate applied (0% < 0.6% < 1.2% < 1 .8%), especially when treated at either 1.0 or 1.5 m in height. Although the volume of the glyphosate used increased with increasing secondary coppice regrowth height (0.5 m < 1.0 m < 1.5 m) due to the larger foliar spraying area, there was little difference in total glyphosate used when comparing the same herbicide rate across the three different heights. The most cost-effective treatment was that where glyphosate was applied at 1.2% when the secondary coppice regrowth was 1-1.5 m. The third trial (also located in Zululand on Eucalyptus grandis x E. urophylla) was implemented to test the knowledge gained in trial two, thereby determinng coppice management regimes that would facilitate mechanised harvesting. In this trial, coppice shoots were reduced to one stem per stump in one thinning operation (coppice reduction heights of 3.5 m, 4.5 m and 6.5 m), with the impact of increased secondary coppice regrowth monitored together with the testing of different control methods. An additional control treatment was included (current best operating practice) with coppice shoots thinned to two stems per stump at shoot height of 3.5 m, and thereafter to original stocking at stem height of 6.5 m. Herbicide rate and timing of application was based on the results obtained in the second trial, with glyphosate applied at 1.2% when the secondary coppice regrowth reached a mean height of approximately 1 m. At the final measurement date, the diameter at breast height for all three coppice reduction height treatments (3.5 m, 4.5 m and 6.5 m) were significantly larger than the additional control treatment. This can be attributed to the allocation of resources to the remaining stem at an earlier age, resulting in a growth benefit. For stocking, the 6.5 m coppice reduction height was significantly higher compared to both the 3.5 m and 4.5 m coppice reduction treatments, while not significantly different from the additional control. In this trial, secondary coppice regrowth had no effect on tree growth. Due to the short duration of this trial, a longer trial period would be necessary to obtain a full understanding of the impacts of the various coppice reduction treatments, and the resulting secondary coppice regrowth influence on selected coppice growth if left untreated. As several previous studies have shown the importance of controlling secondary coppice regrowth, it is recommended not to view the results of this present trial in isolation. On the basis of the results of this research, it can be concluded that the control of coppice regrowth with herbicides is more effective than any of the manual removal treatments in terms of cost, with manual control requiring more follow-up control operations. Even though the manual removal of coppice regrowth had no influence on growth of the remaining stems or planted trees, the potential injury to labourers or growing stock is still of concern. Therefore, the use of herbicides for controlling coppice regrowth would be preferable. However, if reduced herbicide-use is a major criterion, then coppice regrowth can be controlled manually, although at a higher cost.
- Full Text:
- Date Issued: 2017
The use of risk management practices in achieving strategic objectives at the Eastern Cape Socio-Economic Consultative Council (ECSECC)
- Authors: Somniso, Nozuko
- Date: 2017
- Subjects: Risk management -- South Africa -- Eastern Cape Risk management -- Case studies , Strategic planning
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/14367 , vital:27575
- Description: The practices of risk management are important in business, because they allow organisations to improve communication with all stakeholders and to be upfront and proactive in dealing with risks. Risk management also supports the achievement of the organisation’s strategic objectives which leads to a controlled working environment characterised by quality, efficiency and effectiveness. As such it is necessary to understand risk management, its benefits, significance and importance in implementing an organisation’s responsibilities. This understanding is especially vital for ECSECC so that risk management is utilised to achieve strategic objectives in a more deliberate manner. This qualitative study was conducted to demonstrate how ECSECC uses risk management to achieve its strategic objectives by analysing ECSECC’s risk management initiatives, their effectiveness and ultimately to provide recommendations to improve the current practices. The total population of nine executive managers from ECSECC was sampled and the data was collected through personal interviews and the content analysis of ECSECC documents. The findings of the research showed that ECSECC was aware of its risk and risks were identified for 2015/2016 and recorded in ECSECC documents. This awareness was also confirmed by the interview findings. The interview findings also revealed that risk management is indeed embedded in ECSECC activities and there are various risk management interventions in place. However the risk management interventions in mitigating the identified risks were relatively ineffective as certain shortcomings were identified. The study is beneficial to ECSECC management in order to ensure that the current risk management initiatives are effective and that there is a clear connection between the utilisation of risk management in achieving ECSECC’s strategic objectives. Organisations similar to ECSECC can also learn the importance of managing risks effectively to achieve strategic objectives and the benefits of risk management as a management tool.
- Full Text:
- Date Issued: 2017
- Authors: Somniso, Nozuko
- Date: 2017
- Subjects: Risk management -- South Africa -- Eastern Cape Risk management -- Case studies , Strategic planning
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/14367 , vital:27575
- Description: The practices of risk management are important in business, because they allow organisations to improve communication with all stakeholders and to be upfront and proactive in dealing with risks. Risk management also supports the achievement of the organisation’s strategic objectives which leads to a controlled working environment characterised by quality, efficiency and effectiveness. As such it is necessary to understand risk management, its benefits, significance and importance in implementing an organisation’s responsibilities. This understanding is especially vital for ECSECC so that risk management is utilised to achieve strategic objectives in a more deliberate manner. This qualitative study was conducted to demonstrate how ECSECC uses risk management to achieve its strategic objectives by analysing ECSECC’s risk management initiatives, their effectiveness and ultimately to provide recommendations to improve the current practices. The total population of nine executive managers from ECSECC was sampled and the data was collected through personal interviews and the content analysis of ECSECC documents. The findings of the research showed that ECSECC was aware of its risk and risks were identified for 2015/2016 and recorded in ECSECC documents. This awareness was also confirmed by the interview findings. The interview findings also revealed that risk management is indeed embedded in ECSECC activities and there are various risk management interventions in place. However the risk management interventions in mitigating the identified risks were relatively ineffective as certain shortcomings were identified. The study is beneficial to ECSECC management in order to ensure that the current risk management initiatives are effective and that there is a clear connection between the utilisation of risk management in achieving ECSECC’s strategic objectives. Organisations similar to ECSECC can also learn the importance of managing risks effectively to achieve strategic objectives and the benefits of risk management as a management tool.
- Full Text:
- Date Issued: 2017
The use of strategy tools in the non-profit sector
- Authors: Mawila, Melba Hlulani
- Date: 2017
- Subjects: Nonprofit organizations -- South Africa -- Management Strategic planning , Social entrepreneurship
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10948/45453 , vital:38618
- Description: This study undertook to explore the use of strategy tools in the NPO sector and also to determine if there are any differences in the use of tools between social enterprises and traditional NPOs. This was achieved by a Qualitative research methodology, where semi-structured interviews were subsequently conducted to answer the set research questions. The findings of the study indicated that NPOs use a combination of conceptual, material and other strategy tools during their strategizing activities. The findings also suggest that strategy practitioners use strategy tools eclectically by adapting them for their specific context. Lastly, the findings revealed that there are no significant differences in the use of strategy tools between social enterprises and traditional NPOs. The level and pace of change in the business environment has been steadily increasing during the past decades. However, the collapse of the financial markets in 2008/2009 intensified the impact of this change for many organisations. Change impacts organisations in a number of ways. The impact is, amongst others, mostly felt by Non-profit organisations (NPOs). Unlike for-profit organisations, NPOs rely heavily on external funders to fulfil their mission and sustain their organisations. On the other hand, organisations now have to reduce their corporate social responsibility budgets, international funders and governments have to re-direct their funds and individual funders have to tighten their belts.
- Full Text:
- Date Issued: 2017
- Authors: Mawila, Melba Hlulani
- Date: 2017
- Subjects: Nonprofit organizations -- South Africa -- Management Strategic planning , Social entrepreneurship
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10948/45453 , vital:38618
- Description: This study undertook to explore the use of strategy tools in the NPO sector and also to determine if there are any differences in the use of tools between social enterprises and traditional NPOs. This was achieved by a Qualitative research methodology, where semi-structured interviews were subsequently conducted to answer the set research questions. The findings of the study indicated that NPOs use a combination of conceptual, material and other strategy tools during their strategizing activities. The findings also suggest that strategy practitioners use strategy tools eclectically by adapting them for their specific context. Lastly, the findings revealed that there are no significant differences in the use of strategy tools between social enterprises and traditional NPOs. The level and pace of change in the business environment has been steadily increasing during the past decades. However, the collapse of the financial markets in 2008/2009 intensified the impact of this change for many organisations. Change impacts organisations in a number of ways. The impact is, amongst others, mostly felt by Non-profit organisations (NPOs). Unlike for-profit organisations, NPOs rely heavily on external funders to fulfil their mission and sustain their organisations. On the other hand, organisations now have to reduce their corporate social responsibility budgets, international funders and governments have to re-direct their funds and individual funders have to tighten their belts.
- Full Text:
- Date Issued: 2017
The WTO agreement on technical barriers to trade : a critical appraisal of its implementation within the Southern African Development Community
- Authors: Chimeri, Vongai
- Date: 2017
- Subjects: Tariff -- Law and legislation Non-tariff trade barriers -- Law and legislation Foreign trade regulation
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: http://hdl.handle.net/10353/2855 , vital:28108
- Description: The World Trade Organisation Agreement on Technical Barriers to Trade (TBT Agreement) was crafted with the aim of ensuring that technical regulations, standards and conformity assessment procedure do not constitute unnecessary obstacles to international trade. Southern African Development Community (SADC) countries have since ratified this Agreement and took a step further to incorporate its principles into the Technical Barriers to Trade Annex to the SADC Protocol on Trade. Despite this effort, SADC countries are still grappling with implementing the TBT Agreement in their domestic frameworks. Consequently, technical barriers to trade have become impediments to both regional and international trade. It is in this context that this study aims to examine the implementation of the TBT Agreement within the SADC. The study answers the question what are the challenges facing SADC Member states to fully implement the TBT Agreement? The study demonstrates that SADC Member face challenges which include of lack adequate resources, technical expertise and enforcement mechanisms to effectively implement the TBT Agreement. In the finality, the study recommends SADC Member states to deepen regional integration in order to collaborate on matters relating to technical barriers to trade within the region. Member states should also share information and learn from the experiences of other countries on how to effectively implement the TBT Agreement. Further, government officials should be educated on trade-friendly regulations that do not compromise on the principles of the TBT Agreement. To this end, regulatory impact assessments should be established in order to assess the trade effects of both new and old regulations. Effective enforcement mechanisms should also be introduced in order to coerce Member states to comply with their regional obligations. By effecting these recommendations, SADC states have the opportunity to eradicate technical barriers to trade thereby increasing both regional and international trade.
- Full Text:
- Date Issued: 2017
- Authors: Chimeri, Vongai
- Date: 2017
- Subjects: Tariff -- Law and legislation Non-tariff trade barriers -- Law and legislation Foreign trade regulation
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: http://hdl.handle.net/10353/2855 , vital:28108
- Description: The World Trade Organisation Agreement on Technical Barriers to Trade (TBT Agreement) was crafted with the aim of ensuring that technical regulations, standards and conformity assessment procedure do not constitute unnecessary obstacles to international trade. Southern African Development Community (SADC) countries have since ratified this Agreement and took a step further to incorporate its principles into the Technical Barriers to Trade Annex to the SADC Protocol on Trade. Despite this effort, SADC countries are still grappling with implementing the TBT Agreement in their domestic frameworks. Consequently, technical barriers to trade have become impediments to both regional and international trade. It is in this context that this study aims to examine the implementation of the TBT Agreement within the SADC. The study answers the question what are the challenges facing SADC Member states to fully implement the TBT Agreement? The study demonstrates that SADC Member face challenges which include of lack adequate resources, technical expertise and enforcement mechanisms to effectively implement the TBT Agreement. In the finality, the study recommends SADC Member states to deepen regional integration in order to collaborate on matters relating to technical barriers to trade within the region. Member states should also share information and learn from the experiences of other countries on how to effectively implement the TBT Agreement. Further, government officials should be educated on trade-friendly regulations that do not compromise on the principles of the TBT Agreement. To this end, regulatory impact assessments should be established in order to assess the trade effects of both new and old regulations. Effective enforcement mechanisms should also be introduced in order to coerce Member states to comply with their regional obligations. By effecting these recommendations, SADC states have the opportunity to eradicate technical barriers to trade thereby increasing both regional and international trade.
- Full Text:
- Date Issued: 2017
The ‘decolonial turn’: what does it mean for academic staff development?
- Vorster, Jo-Anne, Quinn, Lynn
- Authors: Vorster, Jo-Anne , Quinn, Lynn
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66612 , vital:28971 , https://doi.org/10.17159/1947-9417/2017/853
- Description: publisher version , It has become increasingly evident that the discourse of transformation that has shaped the democratising of higher education institutions over the first two decades of the democratic dispensation in South Africa has now run its course. Over the past few years, and particularly during the tumultuous student protests of 2015 and 2016, students and some academics have been calling for the decolonisation of university structures and cultures, including curricula. Using concepts from Margaret Archer’s social realism we consider the failure of the discourse of transformation to lead to real change and examine a constellation of new discourses related to the decolonisation of universities that have emerged in South Africa recently. Furthermore, we critique the discourses that have underpinned our own practices as academic developers over the past two decades and then explore the implications of what could be termed a ‘decolonial turn’ 1 for academic developers and by implication for the academics with whom they work.
- Full Text:
- Date Issued: 2017
- Authors: Vorster, Jo-Anne , Quinn, Lynn
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66612 , vital:28971 , https://doi.org/10.17159/1947-9417/2017/853
- Description: publisher version , It has become increasingly evident that the discourse of transformation that has shaped the democratising of higher education institutions over the first two decades of the democratic dispensation in South Africa has now run its course. Over the past few years, and particularly during the tumultuous student protests of 2015 and 2016, students and some academics have been calling for the decolonisation of university structures and cultures, including curricula. Using concepts from Margaret Archer’s social realism we consider the failure of the discourse of transformation to lead to real change and examine a constellation of new discourses related to the decolonisation of universities that have emerged in South Africa recently. Furthermore, we critique the discourses that have underpinned our own practices as academic developers over the past two decades and then explore the implications of what could be termed a ‘decolonial turn’ 1 for academic developers and by implication for the academics with whom they work.
- Full Text:
- Date Issued: 2017
Therapist perceptions of narcissism in traditional cultural contexts
- Authors: Puckreesamy, Sashika
- Date: 2017
- Subjects: Narcissism -- South Africa Personality disorders -- South Africa , Psychotherapy-- South Africa Xhosa (African people) -- Psychology Xhosa (African people) -- Social life and customs
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/19872 , vital:28995
- Description: Narcissism, often linked to a sense of entitlement and inflated sense of self, is a complex condition that has been studied for approximately a century. It is typically associated with individualistic cultures, which place emphasis on the self. Although much is known about narcissism, there is far less knowledge on narcissism in collectivist cultures. The Xhosa culture is commonly seen as a collectivist culture. No research to date has been conducted on this construct with Xhosa-speaking South Africans. The aim of the study was to explore and describe therapist perceptions of narcissism in traditional cultural contexts. The objectives of the study included an investigation into how narcissism presents in the Xhosa culture, and an exploration of the narcissistic elements that manifest more prominently. A qualitative, exploratory descriptive research design was employed, and snowball sampling was used to identify psychologists from the Nelson Mandela Metropole for inclusion in the study. Semi-structured interviews were used to gather data, and data was analysed by thematic analysis. The findings of the thematic analysis consisted of six themes, which are thoughts on the Xhosa culture, culture and personality, contemporary Western theory lacking, traits, parenting, and interpersonal and personal difficulties. These themes reflect the participants’ experience, thoughts, and opinions on narcissism in individuals from the Xhosa culture.
- Full Text:
- Date Issued: 2017
- Authors: Puckreesamy, Sashika
- Date: 2017
- Subjects: Narcissism -- South Africa Personality disorders -- South Africa , Psychotherapy-- South Africa Xhosa (African people) -- Psychology Xhosa (African people) -- Social life and customs
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/19872 , vital:28995
- Description: Narcissism, often linked to a sense of entitlement and inflated sense of self, is a complex condition that has been studied for approximately a century. It is typically associated with individualistic cultures, which place emphasis on the self. Although much is known about narcissism, there is far less knowledge on narcissism in collectivist cultures. The Xhosa culture is commonly seen as a collectivist culture. No research to date has been conducted on this construct with Xhosa-speaking South Africans. The aim of the study was to explore and describe therapist perceptions of narcissism in traditional cultural contexts. The objectives of the study included an investigation into how narcissism presents in the Xhosa culture, and an exploration of the narcissistic elements that manifest more prominently. A qualitative, exploratory descriptive research design was employed, and snowball sampling was used to identify psychologists from the Nelson Mandela Metropole for inclusion in the study. Semi-structured interviews were used to gather data, and data was analysed by thematic analysis. The findings of the thematic analysis consisted of six themes, which are thoughts on the Xhosa culture, culture and personality, contemporary Western theory lacking, traits, parenting, and interpersonal and personal difficulties. These themes reflect the participants’ experience, thoughts, and opinions on narcissism in individuals from the Xhosa culture.
- Full Text:
- Date Issued: 2017
Thermally-assisted optically stimulated luminescence from deep electron traps in α-Al2O3: C, Mg
- Kalita, Jitumani M, Chithambo, Makaiko L, Polymeris, G S
- Authors: Kalita, Jitumani M , Chithambo, Makaiko L , Polymeris, G S
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/116133 , vital:34322 , https://doi.org/10.1016/j.nimb.2017.04.075
- Description: We report thermally-assisted optically stimulated luminescence (TA-OSL) in α-Al2O3:C,Mg. The OSL was measured at elevated temperatures between 50 and 240 °C from a sample preheated to 500 °C after irradiation to 100 Gy. That OSL could be measured even after the preheating is direct evidence of the existence of deep electron traps in α-Al2O3:C,Mg. The TA-OSL intensity goes through a peak with measurement temperature. The initial increase is ascribed to thermal assistance to optical stimulation whereas the subsequent decrease in intensity is deduced to reflect increasing incidences of non-radiative recombination, that is, thermal quenching. The activation energy for thermal assistance corresponding to a deep electron trap was estimated as 0.667 ± 0.006 eV whereas the activation energy for thermal quenching was calculated as 0.90 ± 0.04 eV. The intensity of the TA-OSL was also found to increase with irradiation dose. The dose response is sublinear from 25 to 150 Gy but saturates with further increase of dose. The TA-OSL dose response has been discussed by considering the competition for charges at the deep traps. This study incidentally shows that TA-OSL can be effectively used in dosimetry involving large doses.
- Full Text: false
- Date Issued: 2017
- Authors: Kalita, Jitumani M , Chithambo, Makaiko L , Polymeris, G S
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/116133 , vital:34322 , https://doi.org/10.1016/j.nimb.2017.04.075
- Description: We report thermally-assisted optically stimulated luminescence (TA-OSL) in α-Al2O3:C,Mg. The OSL was measured at elevated temperatures between 50 and 240 °C from a sample preheated to 500 °C after irradiation to 100 Gy. That OSL could be measured even after the preheating is direct evidence of the existence of deep electron traps in α-Al2O3:C,Mg. The TA-OSL intensity goes through a peak with measurement temperature. The initial increase is ascribed to thermal assistance to optical stimulation whereas the subsequent decrease in intensity is deduced to reflect increasing incidences of non-radiative recombination, that is, thermal quenching. The activation energy for thermal assistance corresponding to a deep electron trap was estimated as 0.667 ± 0.006 eV whereas the activation energy for thermal quenching was calculated as 0.90 ± 0.04 eV. The intensity of the TA-OSL was also found to increase with irradiation dose. The dose response is sublinear from 25 to 150 Gy but saturates with further increase of dose. The TA-OSL dose response has been discussed by considering the competition for charges at the deep traps. This study incidentally shows that TA-OSL can be effectively used in dosimetry involving large doses.
- Full Text: false
- Date Issued: 2017
Thermodynamic and electrical performance monitoring of a domestic split-type air conditioner and development of a simulation based R22 permanent replacement
- Authors: Bantan, Mafor Glory
- Date: 2017
- Subjects: Air conditioning
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/4857 , vital:28537
- Description: The difficulty that exists in accurately monitoring the performance of air conditioners has made performance prediction an arduous task. Nevertheless, the performance still needs to be monitored and predicted as it helps solve a lot of problems resulting from this technology like effect of the technology on the grid, energy consumption, water utilisation and GHGs emission. With the introduction of regression modelling as a means of system monitoring and prediction some years ago, the accuracy was still a call for concern. It is worth realising that increasing the number of predictors will enhance this method’s accuracy. As such, this document intends to increase the accuracy of this method’s monitoring and predicting ability by increasing the number of predictors to cut across system thermal, environmental and human behavioural variation. These predictors experimentally gotten are used to build an environ-behavioural model that monitors the coefficient of performance and energy consumption of a domestic split-type air conditioner with higher accuracy. Refrigerants have undergone evolution in the past decades in a bid to come up with a refrigerant that has zero ODP, lower – than – R22 GWP and much better than R22 thermodynamic performance. No pure refrigerant has been found to possess these qualities as such mixtures or blends are the best shot at the moment. R410A could stand the test of time to be the long term R22 replacement but for the fact that besides R410A’s higher GWP than that of R22, the former’s system performance is lower than that of the latter’s due to the lower thermodynamic performance of the former. This means the search continues. In this document, a combination of carefully chosen refrigerant components are carefully blended to come up with a simulation based R22 long term replacement, which will be referred to in this document as BTEP.
- Full Text:
- Date Issued: 2017
- Authors: Bantan, Mafor Glory
- Date: 2017
- Subjects: Air conditioning
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/4857 , vital:28537
- Description: The difficulty that exists in accurately monitoring the performance of air conditioners has made performance prediction an arduous task. Nevertheless, the performance still needs to be monitored and predicted as it helps solve a lot of problems resulting from this technology like effect of the technology on the grid, energy consumption, water utilisation and GHGs emission. With the introduction of regression modelling as a means of system monitoring and prediction some years ago, the accuracy was still a call for concern. It is worth realising that increasing the number of predictors will enhance this method’s accuracy. As such, this document intends to increase the accuracy of this method’s monitoring and predicting ability by increasing the number of predictors to cut across system thermal, environmental and human behavioural variation. These predictors experimentally gotten are used to build an environ-behavioural model that monitors the coefficient of performance and energy consumption of a domestic split-type air conditioner with higher accuracy. Refrigerants have undergone evolution in the past decades in a bid to come up with a refrigerant that has zero ODP, lower – than – R22 GWP and much better than R22 thermodynamic performance. No pure refrigerant has been found to possess these qualities as such mixtures or blends are the best shot at the moment. R410A could stand the test of time to be the long term R22 replacement but for the fact that besides R410A’s higher GWP than that of R22, the former’s system performance is lower than that of the latter’s due to the lower thermodynamic performance of the former. This means the search continues. In this document, a combination of carefully chosen refrigerant components are carefully blended to come up with a simulation based R22 long term replacement, which will be referred to in this document as BTEP.
- Full Text:
- Date Issued: 2017
Thermoluminescence of K-Mg-Al-Zn fluorophosphate glass
- Thomas, Sunil, Chithambo, Makaiko L
- Authors: Thomas, Sunil , Chithambo, Makaiko L
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124188 , vital:35574 , https://doi.org/10.1016/j.optmat.2016.12.035
- Description: The thermoluminescence of beta irradiated K-Mg-Al-Zn fluorophosphate glass is reported. A glow-curve corresponding to 10 Gy measured at 1 °C/s shows two peaks, a weaker-intensity one at 70 °C and a more prominent one at 235 °C, the subject of this report. The main peak was observed to fade with delay between irradiation and measurement and specifically, by 11% in 15 h. Its dose response is superlinear in the dose range 1–190 Gy although the change was linear for the initial 10 Gy. Regarding kinetic analysis, the activation energy of the higher temperature peak was evaluated as 1.31 eV and that of the lower temperature peak was found as 0.47 eV. It was also noted that the main peak is affected by thermal quenching with an activation energy for thermal quenching equal to 1.37 eV. It is proposed that the mechanism associated with the thermoluminescence in K-Mg-Al-Zn fluorophosphate glass is that electrons trapped by the metal cations are released during heating and then recombine with holes at oxygen sites.
- Full Text: false
- Date Issued: 2017
- Authors: Thomas, Sunil , Chithambo, Makaiko L
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124188 , vital:35574 , https://doi.org/10.1016/j.optmat.2016.12.035
- Description: The thermoluminescence of beta irradiated K-Mg-Al-Zn fluorophosphate glass is reported. A glow-curve corresponding to 10 Gy measured at 1 °C/s shows two peaks, a weaker-intensity one at 70 °C and a more prominent one at 235 °C, the subject of this report. The main peak was observed to fade with delay between irradiation and measurement and specifically, by 11% in 15 h. Its dose response is superlinear in the dose range 1–190 Gy although the change was linear for the initial 10 Gy. Regarding kinetic analysis, the activation energy of the higher temperature peak was evaluated as 1.31 eV and that of the lower temperature peak was found as 0.47 eV. It was also noted that the main peak is affected by thermal quenching with an activation energy for thermal quenching equal to 1.37 eV. It is proposed that the mechanism associated with the thermoluminescence in K-Mg-Al-Zn fluorophosphate glass is that electrons trapped by the metal cations are released during heating and then recombine with holes at oxygen sites.
- Full Text: false
- Date Issued: 2017
Thermoluminescence of SrAl2O4: Eu2+, Dy3+: kinetic analysis of a composite-peak
- Chithambo, Makaiko L, Wako, A H, Finch, A A
- Authors: Chithambo, Makaiko L , Wako, A H , Finch, A A
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124157 , vital:35571 , https://doi.org/10.1016/j.radmeas.2016.12.009
- Description: The kinetic analysis of thermoluminescence of beta-irradiated SrAl2O4:Eu2+,Dy3+ is reported. The glow-curve is dominated by an apparently-single peak. It has been demonstrated using a number of tests including partial dynamic-heating, isothermal heating, phosphorescence and, the effect of fading, that the peak and the glow-curve consists of a set of closely-spaced peaks. In view of the peak being complex, its first few components were abstracted and analysed and for comparison, the peak was also analysed assuming it is genuinely single.
- Full Text: false
- Date Issued: 2017
- Authors: Chithambo, Makaiko L , Wako, A H , Finch, A A
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124157 , vital:35571 , https://doi.org/10.1016/j.radmeas.2016.12.009
- Description: The kinetic analysis of thermoluminescence of beta-irradiated SrAl2O4:Eu2+,Dy3+ is reported. The glow-curve is dominated by an apparently-single peak. It has been demonstrated using a number of tests including partial dynamic-heating, isothermal heating, phosphorescence and, the effect of fading, that the peak and the glow-curve consists of a set of closely-spaced peaks. In view of the peak being complex, its first few components were abstracted and analysed and for comparison, the peak was also analysed assuming it is genuinely single.
- Full Text: false
- Date Issued: 2017
Thermoluminescence of synthetic quartz annealed beyond its second phase inversion temperature
- Authors: Mthwesi, Zuko
- Date: 2017
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/46077 , vital:25577
- Description: Thermoluminescence of synthetic quartz annealed at 1000 ºC for 10 minutes has been studied. The aim was to study mechanisms of thermoluminescence in annealed synthetic quartz and to discuss the results in terms of the physics of point defects. The sample was irradiated with a beta dose of 10 Gy of beta radiation and then heated at a linear heating rate of 1 ºC.s-1 up to 500 ºC. The thermoluminescence (TL) glow curve consists of three glow peaks. Peak I at 74 0C (main peak) with high intensity as compared to the other two peaks. Peak II at 144 ºC is more intense than peak III at 180 ºC. This study was on the main peak (MP) at 74 ºC and peak III at 180 ºC. Kinetic analysis was carried out to determine the trap depth E, frequency factor s and the order of kinetics b of both peaks using the initial rise, peak shape, variable heating rate, glow curve deconvolution and isothermal TL methods. The values of kinetic parameters obtained were around 0.7 to 1.0 eV for trap depth and in the interval of 108 to 1015 s-¹ for frequency factor for both peaks. The effect of heating rate from 0.5 to 5 ºC.s-¹ on the TL peak intensity and peak temperature was observed. Also the effect of thermal quenching was observed at high heating rates. Since the TL glow curve has overlapping TL peaks, the Tm-Tstop method from 54 ºC up to 64 ºC and E -Tstop methods were introduced where a first order single peak was observed. Phototransfered thermoluminescence (PTTL) was investigated and characterized by three peaks. First PTTL peak I at 72 ºC, peak II at 134 ºC and peak III at 176 ºC. Analysis was carried out on peaks I and III for the effect of dose dependence from 20-200 Gy. Thermal fading was observed on PTTL peaks I and III, after storage time of 30 minutes.
- Full Text:
- Date Issued: 2017
- Authors: Mthwesi, Zuko
- Date: 2017
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/46077 , vital:25577
- Description: Thermoluminescence of synthetic quartz annealed at 1000 ºC for 10 minutes has been studied. The aim was to study mechanisms of thermoluminescence in annealed synthetic quartz and to discuss the results in terms of the physics of point defects. The sample was irradiated with a beta dose of 10 Gy of beta radiation and then heated at a linear heating rate of 1 ºC.s-1 up to 500 ºC. The thermoluminescence (TL) glow curve consists of three glow peaks. Peak I at 74 0C (main peak) with high intensity as compared to the other two peaks. Peak II at 144 ºC is more intense than peak III at 180 ºC. This study was on the main peak (MP) at 74 ºC and peak III at 180 ºC. Kinetic analysis was carried out to determine the trap depth E, frequency factor s and the order of kinetics b of both peaks using the initial rise, peak shape, variable heating rate, glow curve deconvolution and isothermal TL methods. The values of kinetic parameters obtained were around 0.7 to 1.0 eV for trap depth and in the interval of 108 to 1015 s-¹ for frequency factor for both peaks. The effect of heating rate from 0.5 to 5 ºC.s-¹ on the TL peak intensity and peak temperature was observed. Also the effect of thermal quenching was observed at high heating rates. Since the TL glow curve has overlapping TL peaks, the Tm-Tstop method from 54 ºC up to 64 ºC and E -Tstop methods were introduced where a first order single peak was observed. Phototransfered thermoluminescence (PTTL) was investigated and characterized by three peaks. First PTTL peak I at 72 ºC, peak II at 134 ºC and peak III at 176 ºC. Analysis was carried out on peaks I and III for the effect of dose dependence from 20-200 Gy. Thermal fading was observed on PTTL peaks I and III, after storage time of 30 minutes.
- Full Text:
- Date Issued: 2017
Thermoluminescence of the main peak in SrAl2O4: Eu2+, Dy3+: spectral and kinetics features of secondary emission detected in the ultra-violet region
- Authors: Chithambo, Makaiko L
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124197 , vital:35575 , https://doi.org/10.1016/j.radmeas.2016.12.001
- Description: We report the thermoluminescence of SrAl2O4:Eu2+,Dy3+ measured in the ultra-violet region of the spectrum between 300 and 400 nm. Complementary measurements of X-ray excited optical luminescence confirm emission bands of stimulated luminescence in this region. As a further test, optically stimulated luminescence was also measured in this region. The glow curve measured at 1 °C s−1 following irradiation to various doses appears simple and single but is in reality a collection of several components. This was shown by results from the Tm-Tstop method on both ends of the peak, application of thermal cleaning beyond the peak maximum as well as the dependence of the peak on fading. The latter shows that new peaks appear as preceding ones fade. Kinetic analysis of some of the main peaks was carried out giving an activation energy of 0.6 eV. The implication of the results on measurement of phosphorescence, interpretation of dose response and fading is discussed.
- Full Text: false
- Date Issued: 2017
- Authors: Chithambo, Makaiko L
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124197 , vital:35575 , https://doi.org/10.1016/j.radmeas.2016.12.001
- Description: We report the thermoluminescence of SrAl2O4:Eu2+,Dy3+ measured in the ultra-violet region of the spectrum between 300 and 400 nm. Complementary measurements of X-ray excited optical luminescence confirm emission bands of stimulated luminescence in this region. As a further test, optically stimulated luminescence was also measured in this region. The glow curve measured at 1 °C s−1 following irradiation to various doses appears simple and single but is in reality a collection of several components. This was shown by results from the Tm-Tstop method on both ends of the peak, application of thermal cleaning beyond the peak maximum as well as the dependence of the peak on fading. The latter shows that new peaks appear as preceding ones fade. Kinetic analysis of some of the main peaks was carried out giving an activation energy of 0.6 eV. The implication of the results on measurement of phosphorescence, interpretation of dose response and fading is discussed.
- Full Text: false
- Date Issued: 2017
Thermoluminescence of α-Al2O3: C, Mg: kinetic analysis of the main glow peak
- Kalita, Jitumani M, Chithambo, Makaiko L
- Authors: Kalita, Jitumani M , Chithambo, Makaiko L
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/119844 , vital:34788 , https://doi.org/10.1016/j.jlumin.2016.10.031
- Description: The kinetic analysis of the thermoluminescence of aluminium oxide doped with carbon and co-doped with magnesium (α-Al2O3:C,Mg) is reported. Measurements were made at 1 °C/s following beta irradiation to 1 Gy. The glow curve consists of a dominant peak at a peak-maximum Tm of 161 °C and six secondary peaks of weaker intensity at 42, 72, 193, 279, 330 and 370 °C. Kinetic analysis of the main peak, the subject of this report, was carried out using initial rise, whole glow peak, peak shape, curve fitting and variable heating rate methods. The order of kinetics of the main peak was determined as first order using various methods including the Tm–Tstop technique and the dependence of Tm on irradiation dose. The activation energy of the peak is about ~1.36 eV and the frequency factor of the order of 1014 s−1. The peak area changes with heating rate in a manner that shows that the peak is affected by thermal quenching. The activation energy of thermal quenching was evaluated as 0.99±0.08 eV. A comparison of analytical results from the main peak before and after correction for thermal quenching show that the kinetic parameters of the main peak are not that affected by thermal quenching.
- Full Text: false
- Date Issued: 2017
- Authors: Kalita, Jitumani M , Chithambo, Makaiko L
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/119844 , vital:34788 , https://doi.org/10.1016/j.jlumin.2016.10.031
- Description: The kinetic analysis of the thermoluminescence of aluminium oxide doped with carbon and co-doped with magnesium (α-Al2O3:C,Mg) is reported. Measurements were made at 1 °C/s following beta irradiation to 1 Gy. The glow curve consists of a dominant peak at a peak-maximum Tm of 161 °C and six secondary peaks of weaker intensity at 42, 72, 193, 279, 330 and 370 °C. Kinetic analysis of the main peak, the subject of this report, was carried out using initial rise, whole glow peak, peak shape, curve fitting and variable heating rate methods. The order of kinetics of the main peak was determined as first order using various methods including the Tm–Tstop technique and the dependence of Tm on irradiation dose. The activation energy of the peak is about ~1.36 eV and the frequency factor of the order of 1014 s−1. The peak area changes with heating rate in a manner that shows that the peak is affected by thermal quenching. The activation energy of thermal quenching was evaluated as 0.99±0.08 eV. A comparison of analytical results from the main peak before and after correction for thermal quenching show that the kinetic parameters of the main peak are not that affected by thermal quenching.
- Full Text: false
- Date Issued: 2017
These aesthetics are not new: Post-Internet conditions and their effect on contemporary ideas of representation in Painting
- Authors: Grecia, Callan
- Date: 2017
- Subjects: Art and the internet , Digital media -- Philosophy , Technology and the arts , Aesthetics , Painting -- Philosophy
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: http://hdl.handle.net/10962/46333 , vital:25601
- Description: These Aesthetics Are Not New draws inspiration from the effect of digital technological progress on a consumer society. The Internet as a source of ubiquitous imagery reaffirms the idea that in a Post-Internet age there is nothing new, only conditions affected by a networked way of life. In this thesis I attempt to question contemporary ideas of representation and art making, specifically within the medium of oil paint, in a digitally consumed culture of instantaneous access. I interrogate the repetitive imagery that pervades our online experiences, and I speak about how I use my grasp of painterly knowledge and lexicon to replicate digital conditions in the real world to further cement my position that contemporary aesthetics, (digital, physical or both) are not new. I first introduce the reader to the idea of the Post-Internet, exploring the digital’s encroachment on our physical spaces and it’s relation to the politics of the medium of Oil Paint. I then address the concept of the Image-Object, and unpack this idea by comparing and contrasting emoji’s in relation to gestural mark making and the ascription of meaning through iconographic methods in Oil Painting. This culminates in an analysis of my physical practice in relation to these ideas, and concludes with my observations on the future of our ways of seeing, as affected by the Internet and technological progression.
- Full Text:
- Date Issued: 2017
- Authors: Grecia, Callan
- Date: 2017
- Subjects: Art and the internet , Digital media -- Philosophy , Technology and the arts , Aesthetics , Painting -- Philosophy
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: http://hdl.handle.net/10962/46333 , vital:25601
- Description: These Aesthetics Are Not New draws inspiration from the effect of digital technological progress on a consumer society. The Internet as a source of ubiquitous imagery reaffirms the idea that in a Post-Internet age there is nothing new, only conditions affected by a networked way of life. In this thesis I attempt to question contemporary ideas of representation and art making, specifically within the medium of oil paint, in a digitally consumed culture of instantaneous access. I interrogate the repetitive imagery that pervades our online experiences, and I speak about how I use my grasp of painterly knowledge and lexicon to replicate digital conditions in the real world to further cement my position that contemporary aesthetics, (digital, physical or both) are not new. I first introduce the reader to the idea of the Post-Internet, exploring the digital’s encroachment on our physical spaces and it’s relation to the politics of the medium of Oil Paint. I then address the concept of the Image-Object, and unpack this idea by comparing and contrasting emoji’s in relation to gestural mark making and the ascription of meaning through iconographic methods in Oil Painting. This culminates in an analysis of my physical practice in relation to these ideas, and concludes with my observations on the future of our ways of seeing, as affected by the Internet and technological progression.
- Full Text:
- Date Issued: 2017
The design of an adult skills development centre in Hillbrow, Johannesburg, Gauteng
- Authors: Lombard, Danielle
- Date: 2017
- Subjects: Community centers -- Designs and plans Community centers -- Gauteng -- Johannesburg -- Hillbrow --Designs and plans
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/38772 , vital:34964
- Description: This treatise is concerned with the design of an Adult Skills Development Centre in Hillbrow, Johannesburg. The project stems from a personal perception with an understanding of the city as a “place of community” and a perceived need to provide accessible adult education for previously disadvantage communities. The methodology employed in this study is qualitative in nature and the research is concerned with reaching some understanding of community and public space in city structure. This study identifies the broken link in the urban context of Johannesburg, which lacks welldefined public spaces. It, therefore, supports the need for an extension of the existing urban fabric by means of educational and community facilities and well-integrated and connected public spaces. The building within the city of Johannesburg will aim to create a sense of ‘place’ and identity within a multi-cultural society what might unlock the potential for future development in the Inner City. The Skills Development Centre could also act as a social catalyst for further development by activating the most pedestrianized routes along Klein Street and Pretoria Street which will strengthen the connection of the inner city. The difficulty of insensitively placing a new contemporary building into a defined urban context with a historical architectural fabric, was explored through acquiring a critical understanding of both the broader context of Johannesburg and the Inner City as well as its immediate surroundings. This was resolved in the development of a design that acknowledges both place and programme within, the past and present, in a coherent well defined architectural expression.
- Full Text:
- Date Issued: 2017
- Authors: Lombard, Danielle
- Date: 2017
- Subjects: Community centers -- Designs and plans Community centers -- Gauteng -- Johannesburg -- Hillbrow --Designs and plans
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/38772 , vital:34964
- Description: This treatise is concerned with the design of an Adult Skills Development Centre in Hillbrow, Johannesburg. The project stems from a personal perception with an understanding of the city as a “place of community” and a perceived need to provide accessible adult education for previously disadvantage communities. The methodology employed in this study is qualitative in nature and the research is concerned with reaching some understanding of community and public space in city structure. This study identifies the broken link in the urban context of Johannesburg, which lacks welldefined public spaces. It, therefore, supports the need for an extension of the existing urban fabric by means of educational and community facilities and well-integrated and connected public spaces. The building within the city of Johannesburg will aim to create a sense of ‘place’ and identity within a multi-cultural society what might unlock the potential for future development in the Inner City. The Skills Development Centre could also act as a social catalyst for further development by activating the most pedestrianized routes along Klein Street and Pretoria Street which will strengthen the connection of the inner city. The difficulty of insensitively placing a new contemporary building into a defined urban context with a historical architectural fabric, was explored through acquiring a critical understanding of both the broader context of Johannesburg and the Inner City as well as its immediate surroundings. This was resolved in the development of a design that acknowledges both place and programme within, the past and present, in a coherent well defined architectural expression.
- Full Text:
- Date Issued: 2017