Permaculture as an aspect of environmental learning: an investigation into secondary school communities in Zimbabwe
- Authors: Nyika, Mugove Walter
- Date: 2002
- Subjects: Permaculture -- Study and teaching (Secondary) -- Zimbabwe Land use -- Zimbabwe Land use -- Environmental aspects -- Zimbabwe Agriculture -- Zimbabwe Sustainable agriculture -- Zimbabawe
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1960 , http://hdl.handle.net/10962/d1008447
- Description: The Schools and Colleges Permaculture (SCOPE) Programme in Zimbabwe has developed a process for use by schools in planning for the sustainable management of their land. The process is called Integrated Land-Use Design (ILUD) and is based on Permaculture principles. The ILUD process has so far been implemented in 54 pilot schools where it has been used to facilitate the re-design of the school grounds through the active participation of the students, staff and parents. The aim of this research was to investigate what environmental learning takes place during the implementation of the ILUD process and related activities, with a view to informing the improvement of the process. The research was conducted within the interpretive paradigm with particular use being made of the Symbolic Interactionist theoretical framework to explore the social situations in which the ILUD process has been applied. A purposive sample of two schools and five form 4 (grade 11) pupils from each school was selected for the study. The main data collection method was the structured interview. Other data were collected from nonparticipant observations and the analysis of documents, particularly photographs. The data was analysed using the constant comparative method. The findings point towards a significant contribution from the Permaculture activities to the environmental knowledge, environmental management skills and the positive environmental attitudes of the pupils. The work done at the two schools indicates the usefulness of the ILUD process as a tool for environmental action in the schools but its application in the communities was found to be limited by constraints such as lack of resources and the limited capacity of teachers to work in the field of adult education and training. It is recommended that Permaculture should be integrated into the secondary school curriculum if the momentum of the progress made so far is to be maintained. The SCOPE Programme itself needs to be strengthened for its work with communities. There is, for example, a need for adult education and training methods if the introduction of ILUD to the communities is to be successful.
- Full Text:
- Date Issued: 2002
- Authors: Nyika, Mugove Walter
- Date: 2002
- Subjects: Permaculture -- Study and teaching (Secondary) -- Zimbabwe Land use -- Zimbabwe Land use -- Environmental aspects -- Zimbabwe Agriculture -- Zimbabwe Sustainable agriculture -- Zimbabawe
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1960 , http://hdl.handle.net/10962/d1008447
- Description: The Schools and Colleges Permaculture (SCOPE) Programme in Zimbabwe has developed a process for use by schools in planning for the sustainable management of their land. The process is called Integrated Land-Use Design (ILUD) and is based on Permaculture principles. The ILUD process has so far been implemented in 54 pilot schools where it has been used to facilitate the re-design of the school grounds through the active participation of the students, staff and parents. The aim of this research was to investigate what environmental learning takes place during the implementation of the ILUD process and related activities, with a view to informing the improvement of the process. The research was conducted within the interpretive paradigm with particular use being made of the Symbolic Interactionist theoretical framework to explore the social situations in which the ILUD process has been applied. A purposive sample of two schools and five form 4 (grade 11) pupils from each school was selected for the study. The main data collection method was the structured interview. Other data were collected from nonparticipant observations and the analysis of documents, particularly photographs. The data was analysed using the constant comparative method. The findings point towards a significant contribution from the Permaculture activities to the environmental knowledge, environmental management skills and the positive environmental attitudes of the pupils. The work done at the two schools indicates the usefulness of the ILUD process as a tool for environmental action in the schools but its application in the communities was found to be limited by constraints such as lack of resources and the limited capacity of teachers to work in the field of adult education and training. It is recommended that Permaculture should be integrated into the secondary school curriculum if the momentum of the progress made so far is to be maintained. The SCOPE Programme itself needs to be strengthened for its work with communities. There is, for example, a need for adult education and training methods if the introduction of ILUD to the communities is to be successful.
- Full Text:
- Date Issued: 2002
pH study of the electrocatalytic SO2 detection at a glassy carbon electrode modified with iron (II) tetrasulfophthalocyanine
- Thamae, Mamothibe, Westbroek, Philippe, Nyokong, Tebello
- Authors: Thamae, Mamothibe , Westbroek, Philippe , Nyokong, Tebello
- Date: 2002
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/304786 , vital:58490 , xlink:href="https://doi.org/10.1007/s00604-002-0914-8"
- Description: The electrocatalytic determination of SO2 is studied as a function of pH at a glassy carbon electrode modified with iron(II)tetrasulfophthalocyanine ([Fe(II)TSPc]4−). It was found in the literature that depending on pH, SO2·xH2O, HSO3 − and/or SO3 2− are the main compounds in solution, that these compounds behave differently at the electrode surface, and that the condition of the electrode surface is stable over the entire pH-range. The use of SO2(g) or sodium sulfite as starting material did result in identical curves except in the pH range from 7.5–9.0. A possible explanation could be given by proposing that SO2·xH2O is very unstable in the presence of SO3 2−. In strongly acidic medium, SO2·xH2O is the main compound, which can be oxidized as well as reduced with exchange of two electrons. HSO3 − is the main compound at pH = 4 and can also be oxidized and reduced with exchange of, respectively, two and four electrons. In alkaline solution sulfite is the main compound and can only be oxidized, also under exchange of two electrons. Detection limits are in the range of 4.0 ± 0.1 × 10−5 and 7.5 ± 0.1 × 10−5 mol L−1, dependent of pH and of the type of reaction (oxidation or reduction) used.
- Full Text:
- Date Issued: 2002
- Authors: Thamae, Mamothibe , Westbroek, Philippe , Nyokong, Tebello
- Date: 2002
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/304786 , vital:58490 , xlink:href="https://doi.org/10.1007/s00604-002-0914-8"
- Description: The electrocatalytic determination of SO2 is studied as a function of pH at a glassy carbon electrode modified with iron(II)tetrasulfophthalocyanine ([Fe(II)TSPc]4−). It was found in the literature that depending on pH, SO2·xH2O, HSO3 − and/or SO3 2− are the main compounds in solution, that these compounds behave differently at the electrode surface, and that the condition of the electrode surface is stable over the entire pH-range. The use of SO2(g) or sodium sulfite as starting material did result in identical curves except in the pH range from 7.5–9.0. A possible explanation could be given by proposing that SO2·xH2O is very unstable in the presence of SO3 2−. In strongly acidic medium, SO2·xH2O is the main compound, which can be oxidized as well as reduced with exchange of two electrons. HSO3 − is the main compound at pH = 4 and can also be oxidized and reduced with exchange of, respectively, two and four electrons. In alkaline solution sulfite is the main compound and can only be oxidized, also under exchange of two electrons. Detection limits are in the range of 4.0 ± 0.1 × 10−5 and 7.5 ± 0.1 × 10−5 mol L−1, dependent of pH and of the type of reaction (oxidation or reduction) used.
- Full Text:
- Date Issued: 2002
Physical and biological variability in the Antarctic Polar Frontal Zone: report on research cruise 103 of the MV SA Agulhas
- Froneman, P William, Ansorge, Isabelle J, Vumazonke, Lukhanyiso U, Gulekana, A, Bernard, Kim S, Webb, Arthur C M, Leukes, Winston D, Risien, C M, Thomalla, S, Hermes, Juliet, Knott, M, Anderson, D, Hargey, N, Jennings, Michael E, Veitch, J, Lutjeharms, Johan R E, McQuaid, Christopher D
- Authors: Froneman, P William , Ansorge, Isabelle J , Vumazonke, Lukhanyiso U , Gulekana, A , Bernard, Kim S , Webb, Arthur C M , Leukes, Winston D , Risien, C M , Thomalla, S , Hermes, Juliet , Knott, M , Anderson, D , Hargey, N , Jennings, Michael E , Veitch, J , Lutjeharms, Johan R E , McQuaid, Christopher D
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6910 , http://hdl.handle.net/10962/d1011863
- Description: A detailed hydrographic and biological survey was carried out in the region of the South-west Indian Ridge during April 2002. Hydrographic data revealed that the Andrew Bain Fracture Zone, centred at 30oE, 50oS, functions as an important choke point to the flow of the Antarctic Circumpolar Current, resulting in the convergence of the Antarctic Polar Front (APF) and the southern branch of the Sub-Antarctic Front (SSAF). Total chlorophyll-a concentration and zooplankton biomass were highest at stations occupied in the vicinity of two frontal features represented by the APF and SSAF. These data suggest that the region of the South-west Indian Ridge is an area of elevated biological activity and probably acts as an important offshore feeding area for the top predators on the Prince Edward Islands.
- Full Text:
- Date Issued: 2002
- Authors: Froneman, P William , Ansorge, Isabelle J , Vumazonke, Lukhanyiso U , Gulekana, A , Bernard, Kim S , Webb, Arthur C M , Leukes, Winston D , Risien, C M , Thomalla, S , Hermes, Juliet , Knott, M , Anderson, D , Hargey, N , Jennings, Michael E , Veitch, J , Lutjeharms, Johan R E , McQuaid, Christopher D
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6910 , http://hdl.handle.net/10962/d1011863
- Description: A detailed hydrographic and biological survey was carried out in the region of the South-west Indian Ridge during April 2002. Hydrographic data revealed that the Andrew Bain Fracture Zone, centred at 30oE, 50oS, functions as an important choke point to the flow of the Antarctic Circumpolar Current, resulting in the convergence of the Antarctic Polar Front (APF) and the southern branch of the Sub-Antarctic Front (SSAF). Total chlorophyll-a concentration and zooplankton biomass were highest at stations occupied in the vicinity of two frontal features represented by the APF and SSAF. These data suggest that the region of the South-west Indian Ridge is an area of elevated biological activity and probably acts as an important offshore feeding area for the top predators on the Prince Edward Islands.
- Full Text:
- Date Issued: 2002
Physiological and perceptual responses of SANDF personnel to varying combinations of marching speed and backpack load
- Authors: Christie, Candice Jo-Anne
- Date: 2002
- Subjects: Marching -- Physiological aspects , Walking -- Physiological aspects
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5128 , http://hdl.handle.net/10962/d1005207 , Marching -- Physiological aspects , Walking -- Physiological aspects
- Description: The objective of the present study was to establish effective combinations of marching speed and backpack load in order to meet specific military requirements. Thirty infantrymen from the South African National Defence Force (SANDF) comprised the sample and experimental procedures were conducted in a laboratory setting using a Cybex Trotter treadmill. Sixteen conditions were set up which included combinations of four speeds (3.5, 4.5, 5.5, and 6.5 km.h⁻¹) and four backpack loads (20, 35, 50, and 65kg). Each subject was required to complete 8 of the sixteen conditions, each consisting of a six-minute treadmill march. Physiological data (heart rate, ventilation and metabolic responses), kinematic gait responses (step-rate and stride length) and perceptions of exertion (“Central” and “Local” RPE) were collected during the third and sixth minutes of the treadmill march and areas of body discomfort were identified post-march. Responses revealed five distinct categories of exertional strain. Three marches constituted “nominal” (below 40% VO₂max) and three “excessive” strain (above 75% VO₂ max). These represent combinations of extreme military demands and are highly unlikely to be utilised by the military. Three “tolerable” levels of required effort were recommended and these 10 combinations were further divided into three sub-categories. The “moderate” stress marches were identified as “ideal” for prolonged marches and had statistically similar responses of working heart rates (range of 118 bt.min⁻¹ to 127 bt.min⁻¹), energy expenditure (26 kJ.min⁻¹ and 27 kJ.min⁻¹) and ratings of perceived exertion (“Central” ratings of 10 and 11). Thus, marching at 5.5 km.h⁻¹with 20kg, 4.5 km.h⁻¹ with 35kg or 3.5 km.h⁻¹ with 50kg all require a similar energy cost. Four “heavy” category marches were identified for possible use when the duration of the march is reduced. During these marches responses were statistically similar with heart rates ranging from 127 bt.min⁻¹ to 137 bt.min⁻¹, energy expenditure from 32 kJ.min⁻¹ to 37 kJ.min⁻¹ and “Central” ratings of perceived exertion were 12 and 13. When short, high intensity marches are necessary, then combinations from the “very heavy” category may be utilised but with caution. During these marches, soldiers were taxed between 65% and 75% of VO2 max. The results of this study clearly demonstrate that the interplay between speed and load needs to be adjusted when determining “ideal” combinations for specific military demands. Essentially, if speed is of the essence then load must be reduced, and if heavy loads need to be transported then speed must be reduced.
- Full Text:
- Date Issued: 2002
- Authors: Christie, Candice Jo-Anne
- Date: 2002
- Subjects: Marching -- Physiological aspects , Walking -- Physiological aspects
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5128 , http://hdl.handle.net/10962/d1005207 , Marching -- Physiological aspects , Walking -- Physiological aspects
- Description: The objective of the present study was to establish effective combinations of marching speed and backpack load in order to meet specific military requirements. Thirty infantrymen from the South African National Defence Force (SANDF) comprised the sample and experimental procedures were conducted in a laboratory setting using a Cybex Trotter treadmill. Sixteen conditions were set up which included combinations of four speeds (3.5, 4.5, 5.5, and 6.5 km.h⁻¹) and four backpack loads (20, 35, 50, and 65kg). Each subject was required to complete 8 of the sixteen conditions, each consisting of a six-minute treadmill march. Physiological data (heart rate, ventilation and metabolic responses), kinematic gait responses (step-rate and stride length) and perceptions of exertion (“Central” and “Local” RPE) were collected during the third and sixth minutes of the treadmill march and areas of body discomfort were identified post-march. Responses revealed five distinct categories of exertional strain. Three marches constituted “nominal” (below 40% VO₂max) and three “excessive” strain (above 75% VO₂ max). These represent combinations of extreme military demands and are highly unlikely to be utilised by the military. Three “tolerable” levels of required effort were recommended and these 10 combinations were further divided into three sub-categories. The “moderate” stress marches were identified as “ideal” for prolonged marches and had statistically similar responses of working heart rates (range of 118 bt.min⁻¹ to 127 bt.min⁻¹), energy expenditure (26 kJ.min⁻¹ and 27 kJ.min⁻¹) and ratings of perceived exertion (“Central” ratings of 10 and 11). Thus, marching at 5.5 km.h⁻¹with 20kg, 4.5 km.h⁻¹ with 35kg or 3.5 km.h⁻¹ with 50kg all require a similar energy cost. Four “heavy” category marches were identified for possible use when the duration of the march is reduced. During these marches responses were statistically similar with heart rates ranging from 127 bt.min⁻¹ to 137 bt.min⁻¹, energy expenditure from 32 kJ.min⁻¹ to 37 kJ.min⁻¹ and “Central” ratings of perceived exertion were 12 and 13. When short, high intensity marches are necessary, then combinations from the “very heavy” category may be utilised but with caution. During these marches, soldiers were taxed between 65% and 75% of VO2 max. The results of this study clearly demonstrate that the interplay between speed and load needs to be adjusted when determining “ideal” combinations for specific military demands. Essentially, if speed is of the essence then load must be reduced, and if heavy loads need to be transported then speed must be reduced.
- Full Text:
- Date Issued: 2002
Physiological and psychophysical responses of male soldiers to changes in marching gradient, speed and load
- Authors: Todd, Andrew Ivan
- Date: 2002
- Subjects: Soldiers -- South Africa -- Physiology , South Africa Army -- Physical training , Marching -- Physiological aspects , Psychophysiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5129 , http://hdl.handle.net/10962/d1005208 , Soldiers -- South Africa -- Physiology , South Africa Army -- Physical training , Marching -- Physiological aspects , Psychophysiology
- Description: The present study sought to investigate the effects of changes in gradient, under apparently optimal combinations of speed and load, on selected physiological, psychophysical and biophysical responses of military personnel. Subjects (n = 32) were required to march under level (0%), downhill (-10%) and uphill (+10%) conditions. Under each gradient, subjects marched with the following speed-load combinations: 4 km.h-1 carrying 50 kg, 5 km.h-1 carrying 35 kg and 6 km.h-1 carrying 20 kg, a total of nine experimental conditions. Subjects were required to march for six minutes under each condition. Physiological responses (HR, VO2, R, Br, VE, VT, EE) indicated that subjects were not overly taxed by the three speed-load combinations during level marching, which elicited submaximal demands. Furthermore, the results revealed that downhill marching with heavy loads results in similar responses to level marching, while lighter loads may result in significant reductions in physical demands compared to level marching. The physiological responses to uphill marching revealed that subjects were severely physically taxed under these conditions, regardless of speed-load combination. It is unlikely that soldiers would be able to maintain these intensities for an extended period without undue fatigue. It is evident from the psychophysical responses (Rating of Perceived Exertion and Body Discomfort) that subjects perceived the heavy load conditions, regardless of gradient, to be the most stressful on the cardiovascular and muscular systems. The positive gradient conditions also elicited elevated RPE and Body Discomfort responses, while lighter load downhill conditions were perceived to result in the least strain.
- Full Text:
- Date Issued: 2002
- Authors: Todd, Andrew Ivan
- Date: 2002
- Subjects: Soldiers -- South Africa -- Physiology , South Africa Army -- Physical training , Marching -- Physiological aspects , Psychophysiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5129 , http://hdl.handle.net/10962/d1005208 , Soldiers -- South Africa -- Physiology , South Africa Army -- Physical training , Marching -- Physiological aspects , Psychophysiology
- Description: The present study sought to investigate the effects of changes in gradient, under apparently optimal combinations of speed and load, on selected physiological, psychophysical and biophysical responses of military personnel. Subjects (n = 32) were required to march under level (0%), downhill (-10%) and uphill (+10%) conditions. Under each gradient, subjects marched with the following speed-load combinations: 4 km.h-1 carrying 50 kg, 5 km.h-1 carrying 35 kg and 6 km.h-1 carrying 20 kg, a total of nine experimental conditions. Subjects were required to march for six minutes under each condition. Physiological responses (HR, VO2, R, Br, VE, VT, EE) indicated that subjects were not overly taxed by the three speed-load combinations during level marching, which elicited submaximal demands. Furthermore, the results revealed that downhill marching with heavy loads results in similar responses to level marching, while lighter loads may result in significant reductions in physical demands compared to level marching. The physiological responses to uphill marching revealed that subjects were severely physically taxed under these conditions, regardless of speed-load combination. It is unlikely that soldiers would be able to maintain these intensities for an extended period without undue fatigue. It is evident from the psychophysical responses (Rating of Perceived Exertion and Body Discomfort) that subjects perceived the heavy load conditions, regardless of gradient, to be the most stressful on the cardiovascular and muscular systems. The positive gradient conditions also elicited elevated RPE and Body Discomfort responses, while lighter load downhill conditions were perceived to result in the least strain.
- Full Text:
- Date Issued: 2002
Policy and practice : an activity systems' analysis of a further diploma in education (technology)
- Thomen, Eva Christine Salzmann
- Authors: Thomen, Eva Christine Salzmann
- Date: 2002
- Subjects: Action theory Teachers -- Training of -- South Africa Technology -- Study and teaching -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1854 , http://hdl.handle.net/10962/d1004525
- Description: This research examines, within the interpretive paradigm, how emerging educational policy in an in-service educator education programme, namely, a Further Diploma in Education (Technology), is implemented and practiced by educators in the classroom. Technology is a new learning area in the South African curriculum that aims to develop learners' technological skills and promote the practical application of Science and Mathematics. Technology is seen as a way of developing a productive workforce that can design, realise and evaluate technological problems in a global economy. Engestrom's version of Activity Theory was used as the conceptual framework. Activity Theory focuses on 'activity' as a unit of analysis that captures the individual in context. This research focuses on the lecturers' and the students' actions in the programme, and the educators' and the learners' actions in the classroom. The research design was an eclectic case study consisting of two embedded cases within a single larger case namely, in-service educator education. Multiple single cases were selected within the two embedded cases. Trustworthiness and authenticity were addressed through the triangulation of data using mUltiple sources and methods of data collection. Data were analysed and interpreted in a hermeneutic-like process that emerged through gradual induction over time. The findings of the research suggest that the in-service educator education programme did not promote the effective implementation of educational policy. Major challenges to the effective implementation of educational policy include: the formulation and implementation of an INSET programme during rapid educational policy change, the under-preparedness and language difficulties of the participating educators that constrained policy implementation in the INSET programme and the classroom, the role of organisational rules in shaping the activities in the INSET programme and the classroom, and the broader community'S contribution to resource constraints in the classroom. This research suggests that the participating educators are not likely to be major change agents in the transformation of education in South Africa. This concurs with other research findings that suggest that educator education is a weak intervention incapable of overcoming the shortcomings of the educators' own personal schooling or the impact of work experience.
- Full Text:
- Date Issued: 2002
- Authors: Thomen, Eva Christine Salzmann
- Date: 2002
- Subjects: Action theory Teachers -- Training of -- South Africa Technology -- Study and teaching -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1854 , http://hdl.handle.net/10962/d1004525
- Description: This research examines, within the interpretive paradigm, how emerging educational policy in an in-service educator education programme, namely, a Further Diploma in Education (Technology), is implemented and practiced by educators in the classroom. Technology is a new learning area in the South African curriculum that aims to develop learners' technological skills and promote the practical application of Science and Mathematics. Technology is seen as a way of developing a productive workforce that can design, realise and evaluate technological problems in a global economy. Engestrom's version of Activity Theory was used as the conceptual framework. Activity Theory focuses on 'activity' as a unit of analysis that captures the individual in context. This research focuses on the lecturers' and the students' actions in the programme, and the educators' and the learners' actions in the classroom. The research design was an eclectic case study consisting of two embedded cases within a single larger case namely, in-service educator education. Multiple single cases were selected within the two embedded cases. Trustworthiness and authenticity were addressed through the triangulation of data using mUltiple sources and methods of data collection. Data were analysed and interpreted in a hermeneutic-like process that emerged through gradual induction over time. The findings of the research suggest that the in-service educator education programme did not promote the effective implementation of educational policy. Major challenges to the effective implementation of educational policy include: the formulation and implementation of an INSET programme during rapid educational policy change, the under-preparedness and language difficulties of the participating educators that constrained policy implementation in the INSET programme and the classroom, the role of organisational rules in shaping the activities in the INSET programme and the classroom, and the broader community'S contribution to resource constraints in the classroom. This research suggests that the participating educators are not likely to be major change agents in the transformation of education in South Africa. This concurs with other research findings that suggest that educator education is a weak intervention incapable of overcoming the shortcomings of the educators' own personal schooling or the impact of work experience.
- Full Text:
- Date Issued: 2002
Process for the preparation of vanillin from a mixed m-cresol/p-cresol stream
- Authors: Buddoo, Subash
- Date: 2002
- Subjects: Vanillin
- Language: English
- Type: Thesis , Masters , MTech (Chemistry)
- Identifier: vital:10968 , http://hdl.handle.net/10948/138 , Vanillin
- Description: The Vanillin project was undertaken by AECI as it was believed that with the raw materials available from SASOL i.e. cresols, it would be possible to develop a process that would be globally competitive. A process for preparing both vanillin and ethyl vanillin was developed by AECI’s Research and Development Department using a mixed m- and p-cresol stream as feed. The displacement of bromide by methoxide is very successful when using a dimethyl formamide (DMF)/alcohol solvent system and excellent conversions (>95%) and selectivities (>95%) may be obtained. However, the use of DMF, which poses a serious chronic health risk, is unacceptable in this process since the products are intended for use as food and flavouring chemicals. In view of the above the main objectives of this study were: · To find a suitable alternative solvent system, which could produce comparable results while still being economically viable; · To develop an appropriate experimental protocol in the laboratory based on the alternative solvent system; · To determine the important reaction variables by conducting statistically designed experiments; · To optimise the reaction to produce a reproducible and robust experimental protocol; and · To test the reaction thoroughly at bench-scale level and to obtain experimental data for scale-up to pilot plant The most promising alternative solvent system was a methanol/methyl acetate mixture, which produced satisfactory results in the preliminary assessment (conversion of 98.3% and selectivity of 92.0%). DMA and acetonitrile also produced promising results but were not considered for further investigation because of toxicity and cost issues. A set of statistically designed experiments was carried out on the methanol/methyl acetate solvent system where four variables were tested i.e., substrate concentration, temperature, catalyst loading, and methanol to methyl acetate volume ratio. The experimentally determined response surface model showed that the most important variable was catalyst loading (63.2%) for conversion. With respect to selectivity, the most important variables were catalyst loading (31.9%) and methanol to methyl acetate ratio (33.1%). The optimum reaction conditions were as follows: · Temperature: 120°C · Methanol:methyl acetate: 15:1 vol/vol · Catalyst loading: 8 mol % to substrate · Substrate concentration: 22 %m/m on solvent · Catalyst: Copper(I) bromide · Sodium Equivalents: 2.7 wrt substrate · Time: 3 hours The optimum conditions were tested for reproducibility in a 1 Labmax pressure reactor. Replicated reactions, two at a 10% and two at a 20% substrate concentration gave conversions and selectivities all greater than 90%. Although the reaction mixture was a slurry at these concentrations, the reactions were very fast and virtually complete within the first hour (~95% conversion). Initial scale-up studies were conducted in an 8 Parr reactor where five reactions were carried out using the optimum conditions described above. The conversion of substrate and vanillin selectivity was consistently high and compared favourably to the Labmax reactions. The average conversion was 97.3% (96.3 to 98.5%) at an average selectivity of 98.2% (97.4 to 99.1%). A study of the reaction kinetics confirmed that the reaction was first order with respect to the substrate as a plot of substrate concentration versus reaction rate gave a straight line. The rate constant was calculated as 1.1096 k(h-1). The reaction mechanism proposed for the copper assisted nucleophilic aromatic substitution involves the formation of an adduct between sodium methoxide, methyl acetate and copper(I) bromide. The formation of a transient intermediate with the substrate allows intramolecular delivery of the methoxide ion to the aryl moiety through a CuI – CuIII type cycle.
- Full Text:
- Date Issued: 2002
- Authors: Buddoo, Subash
- Date: 2002
- Subjects: Vanillin
- Language: English
- Type: Thesis , Masters , MTech (Chemistry)
- Identifier: vital:10968 , http://hdl.handle.net/10948/138 , Vanillin
- Description: The Vanillin project was undertaken by AECI as it was believed that with the raw materials available from SASOL i.e. cresols, it would be possible to develop a process that would be globally competitive. A process for preparing both vanillin and ethyl vanillin was developed by AECI’s Research and Development Department using a mixed m- and p-cresol stream as feed. The displacement of bromide by methoxide is very successful when using a dimethyl formamide (DMF)/alcohol solvent system and excellent conversions (>95%) and selectivities (>95%) may be obtained. However, the use of DMF, which poses a serious chronic health risk, is unacceptable in this process since the products are intended for use as food and flavouring chemicals. In view of the above the main objectives of this study were: · To find a suitable alternative solvent system, which could produce comparable results while still being economically viable; · To develop an appropriate experimental protocol in the laboratory based on the alternative solvent system; · To determine the important reaction variables by conducting statistically designed experiments; · To optimise the reaction to produce a reproducible and robust experimental protocol; and · To test the reaction thoroughly at bench-scale level and to obtain experimental data for scale-up to pilot plant The most promising alternative solvent system was a methanol/methyl acetate mixture, which produced satisfactory results in the preliminary assessment (conversion of 98.3% and selectivity of 92.0%). DMA and acetonitrile also produced promising results but were not considered for further investigation because of toxicity and cost issues. A set of statistically designed experiments was carried out on the methanol/methyl acetate solvent system where four variables were tested i.e., substrate concentration, temperature, catalyst loading, and methanol to methyl acetate volume ratio. The experimentally determined response surface model showed that the most important variable was catalyst loading (63.2%) for conversion. With respect to selectivity, the most important variables were catalyst loading (31.9%) and methanol to methyl acetate ratio (33.1%). The optimum reaction conditions were as follows: · Temperature: 120°C · Methanol:methyl acetate: 15:1 vol/vol · Catalyst loading: 8 mol % to substrate · Substrate concentration: 22 %m/m on solvent · Catalyst: Copper(I) bromide · Sodium Equivalents: 2.7 wrt substrate · Time: 3 hours The optimum conditions were tested for reproducibility in a 1 Labmax pressure reactor. Replicated reactions, two at a 10% and two at a 20% substrate concentration gave conversions and selectivities all greater than 90%. Although the reaction mixture was a slurry at these concentrations, the reactions were very fast and virtually complete within the first hour (~95% conversion). Initial scale-up studies were conducted in an 8 Parr reactor where five reactions were carried out using the optimum conditions described above. The conversion of substrate and vanillin selectivity was consistently high and compared favourably to the Labmax reactions. The average conversion was 97.3% (96.3 to 98.5%) at an average selectivity of 98.2% (97.4 to 99.1%). A study of the reaction kinetics confirmed that the reaction was first order with respect to the substrate as a plot of substrate concentration versus reaction rate gave a straight line. The rate constant was calculated as 1.1096 k(h-1). The reaction mechanism proposed for the copper assisted nucleophilic aromatic substitution involves the formation of an adduct between sodium methoxide, methyl acetate and copper(I) bromide. The formation of a transient intermediate with the substrate allows intramolecular delivery of the methoxide ion to the aryl moiety through a CuI – CuIII type cycle.
- Full Text:
- Date Issued: 2002
Processes of transformation in a group psychotherapy intervention for single mothers
- Authors: Spiro, Monica
- Date: 2002
- Subjects: Single mothers -- Psychological aspects Group psychotherapy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3100 , http://hdl.handle.net/10962/d1004375
- Description: South African and international statistics indicate that single mother families account for a large and growing proportion of the population. The economic, practical, and emotional stresses of single mothering have been documented and the experience of isolation that often accompanies their circumstances is noted in the literature. Group therapy has been utilised as a treatment plan with single mothers to provide social support and to help the women cope with stress. This thesis examines the experience of single mothers who attended a slow, open group therapy intervention for single mothers at the Child Guidance Clinic, University of Cape Town. The study is located in a feminist social constructionist tradition that recognises the multiplicity of social realities. It places the women's experiences at the foreground of the investigation so as to allow for insight into the socially constructed and first-order reality of the respondents. The research investigates the women's subjective experiences of single parenting; their experiences in the group and its impact on them; and their perceptions of group processes that may have facilitated transformation in their lives. Ten members of the single mother groups were selected for in-depth interviews. Five of the most recent graduates were interviewed and five more participants were selected as the five longest standing members currently participating in the groups. The participants' length of stay in the group at the time of interview varied between eight months and five years. The women were drawn from a range of race, class, cultural and educational backgrounds. The data was collected using individual semi-structured in -depth interviews. A constructivist grounded theory approach was employed to analyse the data. Results revealed the value of the group therapy intervention as a transformative experience for these women who face the challenges of being single parents. The participants highlighted the interpersonal factor of the group intervention as central to their experience and identified this relational aspect as the unique site of their emotional growth. The five interpersonal factors that were identified are: non-judgemental acceptance; support; commonality of experience; reciprocity; and challenge and confrontation between group members. Their accounts of personal changes brought about by participation in the group reflect internal intrapsychic transformations, which are understood in terms of increased se lf-acceptance, enhanced self-esteem, and improved self-confidence. Furthermore, their accounts of personal transformations include a reorganisation of their relational patterns from their immediate to their larger social context. The centrality of relational processes in this research reinforces contemporary theory of women's psychology, particularly theory emerging from the Stone Center, which offers a view of women's psychological growth as occurring in and through participation and engagement with others to achieve more mature and satisfying forms of relating. The accounts of personal and collective transformation provide further insight in to the concept of relational empowerment as it occurs in these groups and offer an understanding of the potentially restorative value of group therapy for single mothers. Future therapeutic interventions are considered and the need for further research in the field is discussed.
- Full Text:
- Date Issued: 2002
- Authors: Spiro, Monica
- Date: 2002
- Subjects: Single mothers -- Psychological aspects Group psychotherapy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3100 , http://hdl.handle.net/10962/d1004375
- Description: South African and international statistics indicate that single mother families account for a large and growing proportion of the population. The economic, practical, and emotional stresses of single mothering have been documented and the experience of isolation that often accompanies their circumstances is noted in the literature. Group therapy has been utilised as a treatment plan with single mothers to provide social support and to help the women cope with stress. This thesis examines the experience of single mothers who attended a slow, open group therapy intervention for single mothers at the Child Guidance Clinic, University of Cape Town. The study is located in a feminist social constructionist tradition that recognises the multiplicity of social realities. It places the women's experiences at the foreground of the investigation so as to allow for insight into the socially constructed and first-order reality of the respondents. The research investigates the women's subjective experiences of single parenting; their experiences in the group and its impact on them; and their perceptions of group processes that may have facilitated transformation in their lives. Ten members of the single mother groups were selected for in-depth interviews. Five of the most recent graduates were interviewed and five more participants were selected as the five longest standing members currently participating in the groups. The participants' length of stay in the group at the time of interview varied between eight months and five years. The women were drawn from a range of race, class, cultural and educational backgrounds. The data was collected using individual semi-structured in -depth interviews. A constructivist grounded theory approach was employed to analyse the data. Results revealed the value of the group therapy intervention as a transformative experience for these women who face the challenges of being single parents. The participants highlighted the interpersonal factor of the group intervention as central to their experience and identified this relational aspect as the unique site of their emotional growth. The five interpersonal factors that were identified are: non-judgemental acceptance; support; commonality of experience; reciprocity; and challenge and confrontation between group members. Their accounts of personal changes brought about by participation in the group reflect internal intrapsychic transformations, which are understood in terms of increased se lf-acceptance, enhanced self-esteem, and improved self-confidence. Furthermore, their accounts of personal transformations include a reorganisation of their relational patterns from their immediate to their larger social context. The centrality of relational processes in this research reinforces contemporary theory of women's psychology, particularly theory emerging from the Stone Center, which offers a view of women's psychological growth as occurring in and through participation and engagement with others to achieve more mature and satisfying forms of relating. The accounts of personal and collective transformation provide further insight in to the concept of relational empowerment as it occurs in these groups and offer an understanding of the potentially restorative value of group therapy for single mothers. Future therapeutic interventions are considered and the need for further research in the field is discussed.
- Full Text:
- Date Issued: 2002
Product development as part of a positioning strategy for the hunting industry in the Eastern Cape
- Van Niekerk, Pieter du Preez
- Authors: Van Niekerk, Pieter du Preez
- Date: 2002
- Subjects: New products -- Marketing , Hunting -- South Africa -- Eastern Cape , Game farms -- South Africa -- Eastern Cape , Venison -- Marketing , Meat industry and trade -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:10894 , http://hdl.handle.net/10948/111 , New products -- Marketing , Hunting -- South Africa -- Eastern Cape , Game farms -- South Africa -- Eastern Cape , Venison -- Marketing , Meat industry and trade -- South Africa -- Eastern Cape
- Description: In this study on product development and positioning in the hunting industry in the Eastern Cape, two conceptual frameworks were developed, based on a literature study. These positioning and product development concepts were tested against primary and secondary information gathered about the hunting industry. The game and hunting industries were in a strong growth phase at the time of this study. These industries are playing an increasingly important role in the economy of the Eastern Cape, and more and more agricultural land is utilised for game ranching. From the perspective of obtaining a competitive advantage in an increasingly competitive environment, it is therefore important for hunting providers to develop suitable products, and to position these products correctly. It is also important to investigate the characteristics of the game and hunting industries in the Eastern Cape and to get information about the characteristics of the market in which product development and positioning take place. Hunting is the most important form of game utilisation in the Eastern Cape, followed by cropping of game and live game sales. At the time of this study, the total value of the game utilised annually in the Eastern Cape was in excess of R168 million. Game utilisation seemed to be taking place on a sustainable basis, as the number of animals utilised annually was less than the annual production. Kudu and springbok provide the biggest total income, and, together with mountain reedbuck, are the most abundant species in the Eastern Cape. The main game-producing areas in the Eastern Cape coincide with the areas where extensive beef, sheep and goat farming are practised. The hunting products on offer from hunting providers, differ in certain ways. Aspects like price, type of hunting provided, game species available for hunting, terrain where hunting takes place, and various other aspects in connection with the hunt, differ from hunting provider to hunting provider. Characteristics of the hunting experience that hunters desire may be divided into core and variable elements. The core elements include: · the conditions pertaining to the hunt being spelt out clearly; · the maintenance of safety standards; · reasonable day fees; · the presence of game in sufficient numbers; and · other aspects generally desired by hunters. In the study it was found that the needs of hunters also differ regarding certain aspects of the hunting experience. These variable elements include price levels, type and availability of accommodation, and the role of the hunting provider. The core aspects that hunters desire are as a rule part of the product offering. From a product development perspective, the variable elements provide an opportunity to customise products to hunter needs. The inclusion or exclusion of variable elements from the product offering give rise to certain unique product features, and therefore provide the opportunity for product differentiation. After development, products are positioned firstly by selecting a market segment to focus on. Secondly, the needs of hunters in the target segment should be clearly identified, followed by the development of suitable products based on hunter needs, and taking into account the features of competitive offerings. Decisions should also be taken about the features to be included in the product offering to achieve product differentiation. After development of a suitable product, an image or brand should be chosen for the product, and this image should be effectively communicated to the market. A number of possible positioning options were identified for hunting providers. It was found that factors like the physical features of the ranch, available infrastructure, the market segment chosen, desires of the hunting providers, and the perception of the needs of hunters, eventually influence decisions about product development and positioning. The final decisions on positioning should take the core competencies of the hunting provider into account and should ensure that the hunting provider has the ability to fill the chosen position in the market.
- Full Text:
- Date Issued: 2002
- Authors: Van Niekerk, Pieter du Preez
- Date: 2002
- Subjects: New products -- Marketing , Hunting -- South Africa -- Eastern Cape , Game farms -- South Africa -- Eastern Cape , Venison -- Marketing , Meat industry and trade -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:10894 , http://hdl.handle.net/10948/111 , New products -- Marketing , Hunting -- South Africa -- Eastern Cape , Game farms -- South Africa -- Eastern Cape , Venison -- Marketing , Meat industry and trade -- South Africa -- Eastern Cape
- Description: In this study on product development and positioning in the hunting industry in the Eastern Cape, two conceptual frameworks were developed, based on a literature study. These positioning and product development concepts were tested against primary and secondary information gathered about the hunting industry. The game and hunting industries were in a strong growth phase at the time of this study. These industries are playing an increasingly important role in the economy of the Eastern Cape, and more and more agricultural land is utilised for game ranching. From the perspective of obtaining a competitive advantage in an increasingly competitive environment, it is therefore important for hunting providers to develop suitable products, and to position these products correctly. It is also important to investigate the characteristics of the game and hunting industries in the Eastern Cape and to get information about the characteristics of the market in which product development and positioning take place. Hunting is the most important form of game utilisation in the Eastern Cape, followed by cropping of game and live game sales. At the time of this study, the total value of the game utilised annually in the Eastern Cape was in excess of R168 million. Game utilisation seemed to be taking place on a sustainable basis, as the number of animals utilised annually was less than the annual production. Kudu and springbok provide the biggest total income, and, together with mountain reedbuck, are the most abundant species in the Eastern Cape. The main game-producing areas in the Eastern Cape coincide with the areas where extensive beef, sheep and goat farming are practised. The hunting products on offer from hunting providers, differ in certain ways. Aspects like price, type of hunting provided, game species available for hunting, terrain where hunting takes place, and various other aspects in connection with the hunt, differ from hunting provider to hunting provider. Characteristics of the hunting experience that hunters desire may be divided into core and variable elements. The core elements include: · the conditions pertaining to the hunt being spelt out clearly; · the maintenance of safety standards; · reasonable day fees; · the presence of game in sufficient numbers; and · other aspects generally desired by hunters. In the study it was found that the needs of hunters also differ regarding certain aspects of the hunting experience. These variable elements include price levels, type and availability of accommodation, and the role of the hunting provider. The core aspects that hunters desire are as a rule part of the product offering. From a product development perspective, the variable elements provide an opportunity to customise products to hunter needs. The inclusion or exclusion of variable elements from the product offering give rise to certain unique product features, and therefore provide the opportunity for product differentiation. After development, products are positioned firstly by selecting a market segment to focus on. Secondly, the needs of hunters in the target segment should be clearly identified, followed by the development of suitable products based on hunter needs, and taking into account the features of competitive offerings. Decisions should also be taken about the features to be included in the product offering to achieve product differentiation. After development of a suitable product, an image or brand should be chosen for the product, and this image should be effectively communicated to the market. A number of possible positioning options were identified for hunting providers. It was found that factors like the physical features of the ranch, available infrastructure, the market segment chosen, desires of the hunting providers, and the perception of the needs of hunters, eventually influence decisions about product development and positioning. The final decisions on positioning should take the core competencies of the hunting provider into account and should ensure that the hunting provider has the ability to fill the chosen position in the market.
- Full Text:
- Date Issued: 2002
Promotion of liberal values in South African foreign policy : beyond the structural imperatives of the international system?
- Authors: Mkalipi, Zanethemba
- Date: 2002
- Subjects: South Africa -- Foreign relations
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:2865 , http://hdl.handle.net/10962/d1007662 , South Africa -- Foreign relations
- Description: The end of the Cold War in the early 1990s led to a multilateral international system no longer divided by contending forces of capitalism and communism. In the context of South Africa, the end of the Cold War occurred at a juncture where the apartheid government was being challenged by pro-democracy forces that have fought against it for decades. The developments in the international system and in the country led to South Africa adopting universal liberal values not only in its constitution, but also in its international relations. Foreign policy documents and statements by the ministry of Foreign Affairs also reflected the country's aspiration of becoming a mediator, a facilitator for democracy and a peacemaker especially in the context of Africa. International expectation mounted as South Africa was perceived as possessing the capacity to act in a manner that advances democratic values and which gives voice to the weak nations of the world. However, the aura of a post-apartheid South Africa that would act not only in its interest, but also in the interest of the world community never fully materialised. South Africa failed to act in a manner consistent with its stated commitment to democratic values when it recognised Peoples Republic of China, an undemocratic and repressive government. It also marched into Lesotho in 1998, resulting in the destabilisation of this tiny Southern African country. These events led to an increasing criticism of the South African government. Some argued that South Africa was still inexperienced given its recent emergence as a world player. Others blamed the inconsistency on a too broad and ambitious foreign policy that set itself for failure. This study seeks to contribute to the conceptual understanding of the debate regarding the ambiguous nature of South Africa's foreign policy behaviour. It situates the conceptualisation of South Africa's foreign policy within the predominant debates in international relations between realism, political structuralism and pluralism. Firstly, it holds that the end of the Cold War and ascendancy of globalist conceptions of international relations did not lead to the inadequacy of political structuralism as an organising framework. Secondly, it attempts to clarify the gap between South Africa's foreign policy and foreign policy behaviour by employing the assumptions advanced by political structuralism, Thirdly, a case study of South Africa's foreign policy towards China, Lesotho, the Great Lakes and Swaziland is carried out. Here it is demonstrated that the ambiguities of South Africa's foreign policy are a function of the constraints imposed by the political and economic structure of the international system, It draws its conclusion by providing methodological recommendations to South Africa's foreign policy makers and future researchers in the field of foreign policy analysis.
- Full Text:
- Date Issued: 2002
- Authors: Mkalipi, Zanethemba
- Date: 2002
- Subjects: South Africa -- Foreign relations
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:2865 , http://hdl.handle.net/10962/d1007662 , South Africa -- Foreign relations
- Description: The end of the Cold War in the early 1990s led to a multilateral international system no longer divided by contending forces of capitalism and communism. In the context of South Africa, the end of the Cold War occurred at a juncture where the apartheid government was being challenged by pro-democracy forces that have fought against it for decades. The developments in the international system and in the country led to South Africa adopting universal liberal values not only in its constitution, but also in its international relations. Foreign policy documents and statements by the ministry of Foreign Affairs also reflected the country's aspiration of becoming a mediator, a facilitator for democracy and a peacemaker especially in the context of Africa. International expectation mounted as South Africa was perceived as possessing the capacity to act in a manner that advances democratic values and which gives voice to the weak nations of the world. However, the aura of a post-apartheid South Africa that would act not only in its interest, but also in the interest of the world community never fully materialised. South Africa failed to act in a manner consistent with its stated commitment to democratic values when it recognised Peoples Republic of China, an undemocratic and repressive government. It also marched into Lesotho in 1998, resulting in the destabilisation of this tiny Southern African country. These events led to an increasing criticism of the South African government. Some argued that South Africa was still inexperienced given its recent emergence as a world player. Others blamed the inconsistency on a too broad and ambitious foreign policy that set itself for failure. This study seeks to contribute to the conceptual understanding of the debate regarding the ambiguous nature of South Africa's foreign policy behaviour. It situates the conceptualisation of South Africa's foreign policy within the predominant debates in international relations between realism, political structuralism and pluralism. Firstly, it holds that the end of the Cold War and ascendancy of globalist conceptions of international relations did not lead to the inadequacy of political structuralism as an organising framework. Secondly, it attempts to clarify the gap between South Africa's foreign policy and foreign policy behaviour by employing the assumptions advanced by political structuralism, Thirdly, a case study of South Africa's foreign policy towards China, Lesotho, the Great Lakes and Swaziland is carried out. Here it is demonstrated that the ambiguities of South Africa's foreign policy are a function of the constraints imposed by the political and economic structure of the international system, It draws its conclusion by providing methodological recommendations to South Africa's foreign policy makers and future researchers in the field of foreign policy analysis.
- Full Text:
- Date Issued: 2002
Psychological resilience: the role of unconscious and conscious coping strategies in the mediation of stress in high risk occupational contexts
- Authors: Alexander, Debra Geraldine
- Date: 2002
- Subjects: Hazardous occupations , Teachers -- South Africa -- Job stress , Police -- South Africa -- Job stress , Emergency medical personnel -- South Africa -- Job stress , Stress (Psychology)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3092 , http://hdl.handle.net/10962/d1003059 , Hazardous occupations , Teachers -- South Africa -- Job stress , Police -- South Africa -- Job stress , Emergency medical personnel -- South Africa -- Job stress , Stress (Psychology)
- Description: This study investigates the role of unconscious and conscious coping strategies in the mediation of stress in high risk occupational contexts. The Social Readjustment Rating Scale, the Multidimensional Coping Inventory and the Defense Style Questionnaires were completed by 194 police, ambulance and teaching personnel. A sample of 37 teachers served as a non high risk occupation control group. Descriptive statistics, regression analysis, analysis of variance, analysis of difference and principal component analysis were performed on the data. Results indicated minimal significant between group differences. Within group variances were yielded. A minor relationship between levels of stress and usage of positive and negative mechanisms was observed. The significance of these findings is discussed and recommendations made for further study.
- Full Text:
- Date Issued: 2002
- Authors: Alexander, Debra Geraldine
- Date: 2002
- Subjects: Hazardous occupations , Teachers -- South Africa -- Job stress , Police -- South Africa -- Job stress , Emergency medical personnel -- South Africa -- Job stress , Stress (Psychology)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3092 , http://hdl.handle.net/10962/d1003059 , Hazardous occupations , Teachers -- South Africa -- Job stress , Police -- South Africa -- Job stress , Emergency medical personnel -- South Africa -- Job stress , Stress (Psychology)
- Description: This study investigates the role of unconscious and conscious coping strategies in the mediation of stress in high risk occupational contexts. The Social Readjustment Rating Scale, the Multidimensional Coping Inventory and the Defense Style Questionnaires were completed by 194 police, ambulance and teaching personnel. A sample of 37 teachers served as a non high risk occupation control group. Descriptive statistics, regression analysis, analysis of variance, analysis of difference and principal component analysis were performed on the data. Results indicated minimal significant between group differences. Within group variances were yielded. A minor relationship between levels of stress and usage of positive and negative mechanisms was observed. The significance of these findings is discussed and recommendations made for further study.
- Full Text:
- Date Issued: 2002
Quantification of corticosteroid-induced skin vasoconstriction: visual ranking, chromameter measurement or digital image analysis
- Smith, Eric W, Haigh, John M, Surber, Christian
- Authors: Smith, Eric W , Haigh, John M , Surber, Christian
- Date: 2002
- Language: English
- Type: text , Article
- Identifier: vital:6427 , http://hdl.handle.net/10962/d1006564
- Description: Topical corticosteroid formulations have been evaluated by visual grading protocols for many years. Toward a more objective methodology, several instrumental methods have been evaluated for applicability in quantifying the vasoconstriction side-effect that follows corticosteroid application to the skin. Although the chromameter has been adopted by regulatory bodies throughout the world as the current standard for topical bioequivalence determinations, there is considerable criticism of this instrument from several quarters. A preliminary comparison reported here indicates that digital image analysis provides statistically significant results that are similar to those obtained by visual assessment techniques, and shows considerably greater precision than that obtained by the chromameter. Continued evaluation of objective assessment techniques, such as digital imaging, and continued modernisation of regulatory bioequivalence requirements will assist in protecting patients and optimising clinical results.
- Full Text:
- Date Issued: 2002
- Authors: Smith, Eric W , Haigh, John M , Surber, Christian
- Date: 2002
- Language: English
- Type: text , Article
- Identifier: vital:6427 , http://hdl.handle.net/10962/d1006564
- Description: Topical corticosteroid formulations have been evaluated by visual grading protocols for many years. Toward a more objective methodology, several instrumental methods have been evaluated for applicability in quantifying the vasoconstriction side-effect that follows corticosteroid application to the skin. Although the chromameter has been adopted by regulatory bodies throughout the world as the current standard for topical bioequivalence determinations, there is considerable criticism of this instrument from several quarters. A preliminary comparison reported here indicates that digital image analysis provides statistically significant results that are similar to those obtained by visual assessment techniques, and shows considerably greater precision than that obtained by the chromameter. Continued evaluation of objective assessment techniques, such as digital imaging, and continued modernisation of regulatory bioequivalence requirements will assist in protecting patients and optimising clinical results.
- Full Text:
- Date Issued: 2002
Racializing teenage pregnancy : ‘culture’ and ‘tradition’ in the South African scientific literature
- Macleod, Catriona I, Durrheim, Kevin
- Authors: Macleod, Catriona I , Durrheim, Kevin
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6260 , http://hdl.handle.net/10962/d1007878
- Description: The signifiers, ‘race’, ‘culture’ or ‘ethnicity’ are utilized in the teenage pregnancy literature (1) to highlight ‘differences’ in adolescent sexual and reproductive behaviour and (2) as explanatory tools. When ‘white’ teenagers are the focus of research, psychological explanations are usually invoked, while for ‘black’ teenagers, explanations are socio-cultural in nature. In this paper, we explore how, through a process of racialization, the psycho-medical literature on teenage pregnancy in South Africa contributes to the entrenchment of ‘race’, ‘culture’ and ‘ethnicity’ as fixed, ‘natural’ signifiers. We utilize Derrida’s notion of différance, together with Phoenix and Woollett’s adaptation – ‘normalized absence/pathologized presence’ – to indicate how ‘black’ people are cast as the Other, the pathologized presence which relies on the normalized absent trace, ‘whiteness’, for definition. We analyse how the notions of ‘tradition’ and ‘culture’ are deployed to sanitize or disguise the underlying racializing project. ‘Black’ is exoticized and rendered strange and thus open to scrutiny, monitoring and intervention. ‘Culture’ and ‘tradition’ appeal to the myth of origin, thus providing pseudo-historical explanations which essentialize and naturalize racialized collectivities. , Rhodes University
- Full Text:
- Date Issued: 2002
Racializing teenage pregnancy : ‘culture’ and ‘tradition’ in the South African scientific literature
- Authors: Macleod, Catriona I , Durrheim, Kevin
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6260 , http://hdl.handle.net/10962/d1007878
- Description: The signifiers, ‘race’, ‘culture’ or ‘ethnicity’ are utilized in the teenage pregnancy literature (1) to highlight ‘differences’ in adolescent sexual and reproductive behaviour and (2) as explanatory tools. When ‘white’ teenagers are the focus of research, psychological explanations are usually invoked, while for ‘black’ teenagers, explanations are socio-cultural in nature. In this paper, we explore how, through a process of racialization, the psycho-medical literature on teenage pregnancy in South Africa contributes to the entrenchment of ‘race’, ‘culture’ and ‘ethnicity’ as fixed, ‘natural’ signifiers. We utilize Derrida’s notion of différance, together with Phoenix and Woollett’s adaptation – ‘normalized absence/pathologized presence’ – to indicate how ‘black’ people are cast as the Other, the pathologized presence which relies on the normalized absent trace, ‘whiteness’, for definition. We analyse how the notions of ‘tradition’ and ‘culture’ are deployed to sanitize or disguise the underlying racializing project. ‘Black’ is exoticized and rendered strange and thus open to scrutiny, monitoring and intervention. ‘Culture’ and ‘tradition’ appeal to the myth of origin, thus providing pseudo-historical explanations which essentialize and naturalize racialized collectivities. , Rhodes University
- Full Text:
- Date Issued: 2002
RADGIS - an improved architecture for runtime-extensible, distributed GIS applications
- Authors: Preston, Richard Michael
- Date: 2002
- Subjects: Geographic information systems
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4626 , http://hdl.handle.net/10962/d1006497
- Description: A number of GIS architectures and technologies have emerged recently to facilitate the visualisation and processing of geospatial data over the Web. The work presented in this dissertation builds on these efforts and undertakes to overcome some of the major problems with traditional GIS client architectures, including application bloat, lack of customisability, and lack of interoperability between GIS products. In this dissertation we describe how a new client-side GIS architecture was developed and implemented as a proof-of-concept application called RADGIS, which is based on open standards and emerging distributed component-based software paradigms. RADGIS reflects the current trend in development focus from Web browser-based applications to customised clients, based on open standards, that make use of distributed Web services. While much attention has been paid to exposing data on the Web, there is growing momentum towards providing “value-added” services. A good example of this is the tremendous industry interest in the provision of location-based services, which has been discussed as a special use-case of our RADGIS architecture. Thus, in the near future client applications will not simply be used to access data transparently, but will also become facilitators for the location-transparent invocation of local and remote services. This flexible architecture will ensure that data can be stored and processed independently of the location of the client that wishes to view or interact with it. Our RADGIS application enables content developers and end-users to create and/or customise GIS applications dynamically at runtime through the incorporation of GIS services. This ensures that the client application has the flexibility to withstand changing levels of expertise or user requirements. These GIS services are implemented as components that execute locally on the client machine, or as remote CORBA Objects or EJBs. Assembly and deployment of these components is achieved using a specialised XML descriptor. This XML descriptor is written using a markup language that we developed specifically for this purpose, called DGCML, which contains deployment information, as well as a GUI specification and links to an XML-based help system that can be merged with the RADGIS client application’s existing help system. Thus, no additional requirements are imposed on object developers by the RADGIS architecture, i.e. there is no need to rewrite existing objects since DGCML acts as a runtime-customisable wrapper, allowing existing objects to be utilised by RADGIS. While the focus of this thesis has been on overcoming the above-mentioned problems with traditional GIS applications, the work described here can also be applied in a much broader context, especially in the development of highly customisable client applications that are able to integrate Web services at runtime.
- Full Text:
- Date Issued: 2002
- Authors: Preston, Richard Michael
- Date: 2002
- Subjects: Geographic information systems
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4626 , http://hdl.handle.net/10962/d1006497
- Description: A number of GIS architectures and technologies have emerged recently to facilitate the visualisation and processing of geospatial data over the Web. The work presented in this dissertation builds on these efforts and undertakes to overcome some of the major problems with traditional GIS client architectures, including application bloat, lack of customisability, and lack of interoperability between GIS products. In this dissertation we describe how a new client-side GIS architecture was developed and implemented as a proof-of-concept application called RADGIS, which is based on open standards and emerging distributed component-based software paradigms. RADGIS reflects the current trend in development focus from Web browser-based applications to customised clients, based on open standards, that make use of distributed Web services. While much attention has been paid to exposing data on the Web, there is growing momentum towards providing “value-added” services. A good example of this is the tremendous industry interest in the provision of location-based services, which has been discussed as a special use-case of our RADGIS architecture. Thus, in the near future client applications will not simply be used to access data transparently, but will also become facilitators for the location-transparent invocation of local and remote services. This flexible architecture will ensure that data can be stored and processed independently of the location of the client that wishes to view or interact with it. Our RADGIS application enables content developers and end-users to create and/or customise GIS applications dynamically at runtime through the incorporation of GIS services. This ensures that the client application has the flexibility to withstand changing levels of expertise or user requirements. These GIS services are implemented as components that execute locally on the client machine, or as remote CORBA Objects or EJBs. Assembly and deployment of these components is achieved using a specialised XML descriptor. This XML descriptor is written using a markup language that we developed specifically for this purpose, called DGCML, which contains deployment information, as well as a GUI specification and links to an XML-based help system that can be merged with the RADGIS client application’s existing help system. Thus, no additional requirements are imposed on object developers by the RADGIS architecture, i.e. there is no need to rewrite existing objects since DGCML acts as a runtime-customisable wrapper, allowing existing objects to be utilised by RADGIS. While the focus of this thesis has been on overcoming the above-mentioned problems with traditional GIS applications, the work described here can also be applied in a much broader context, especially in the development of highly customisable client applications that are able to integrate Web services at runtime.
- Full Text:
- Date Issued: 2002
Radiocarbon dates and the Late Quaternary palaeogeography of the Province of the Eastern Cape, South Africa
- Authors: Lewis, Colin A
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6693 , http://hdl.handle.net/10962/d1006728
- Description: A total of 193 dates are listed from the Eastern Cape. Middle Stone Age hunter-gatherers existed in the Drakensberg prior to the rigours of cold climatic conditions after ca. 22,000 BP. These uplands were reoccupied under more favourable climatic conditions after ca. 12,600 BP but were apparently abandoned between ca. 6000 BP and 3000 BP. Hunter-gatherer occupation throughout the Holocene is indicated at lower altitudes, with in-migration of pastoralists ca. 1800 BP in the Fish River area, and with Iron Age farmers entering coastal districts and adjacent river valleys from ca. 1400 BP. Sand dunes accumulated in the Holocene adjacent to the Indian Ocean. Flood plain development in the early Holocene was succeeded by incision of rivers in the later Holocene. Flood plain deposition began again in the Southern Drakensberg ca. 1000 BP. Palynological studies evidence marked climatic oscillations around the Late Glacial/Holocene boundary, with apparent stability at high altitude subsequent to 2700 BP.
- Full Text:
- Date Issued: 2002
- Authors: Lewis, Colin A
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6693 , http://hdl.handle.net/10962/d1006728
- Description: A total of 193 dates are listed from the Eastern Cape. Middle Stone Age hunter-gatherers existed in the Drakensberg prior to the rigours of cold climatic conditions after ca. 22,000 BP. These uplands were reoccupied under more favourable climatic conditions after ca. 12,600 BP but were apparently abandoned between ca. 6000 BP and 3000 BP. Hunter-gatherer occupation throughout the Holocene is indicated at lower altitudes, with in-migration of pastoralists ca. 1800 BP in the Fish River area, and with Iron Age farmers entering coastal districts and adjacent river valleys from ca. 1400 BP. Sand dunes accumulated in the Holocene adjacent to the Indian Ocean. Flood plain development in the early Holocene was succeeded by incision of rivers in the later Holocene. Flood plain deposition began again in the Southern Drakensberg ca. 1000 BP. Palynological studies evidence marked climatic oscillations around the Late Glacial/Holocene boundary, with apparent stability at high altitude subsequent to 2700 BP.
- Full Text:
- Date Issued: 2002
Reading William Blake and T.S. Eliot: contrary poets, progressive vision
- Authors: Rayneard, Max James Anthony
- Date: 2002
- Subjects: Blake, William, 1757-1827 -- Criticism and interpretation , Eliot, T. S. (Thomas Stearns), 1888-1965 -- Criticism and interpretation
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2279 , http://hdl.handle.net/10962/d1007545 , Blake, William, 1757-1827 -- Criticism and interpretation , Eliot, T. S. (Thomas Stearns), 1888-1965 -- Criticism and interpretation
- Description: Many critics resort to explaining readers' experiences of poems like William Blake's Jerusalem and T.S. Eliot's Four Quartets in terms of "spirituality" or "religion". These experiences are broadly defined in this thesis as jouissance (after Roland Barthes' essay The Pleasure of the Text) or "experience qua experience". Critical attempts at the reduction of jouissance into abstract constructs serve merely as stopgap measures by which critics might avoid having to account for the limits of their own rational discourse. These poems, in particular, are deliberately structured to preserve the reader's experience of the poem from reduction to any particular meta-discursive construct, including "the spiritual". Through a broad application of Rezeption-Asthetik principles, this thesis demonstrates how the poems are structured to direct readers' faculties to engage with the hypothetical realm within which jouissance occurs, beyond the rationally abstractable. T.S. Eliot's poetic oeuvre appears to chart his growing confidence in non-rational, pre-critical faculties. Through "The Love Song of J. Alfred Prufrock", The Waste Land, and Four Quartets, Eliot's poetry becomes gradually less prescriptive of the terms to which the experience of his poetry might be reduced. In Four Quartets he finally entrusts readers with a great deal of responsibility for "co-creating" the poem's significance. Like T.S . Eliot, although more consistently throughout his oeuvre, William Blake is similarly concerned with the validation of the reader's subjective interpretative/creative faculties. Blake's Jerusalem is carefully structured on various intertwined levels to rouse and exercise in the reader what the poet calls the "All Glorious Imagination" (Keynes 1972: 679). The jouissance of Jerusalem or Four Quartets is located in the reader's efforts to co-create the significance of the poems. It is only during a direct engagement with this process, rather than in subsequent attempts to abstract it, that the "experience qua experience" may be understood.
- Full Text:
- Date Issued: 2002
- Authors: Rayneard, Max James Anthony
- Date: 2002
- Subjects: Blake, William, 1757-1827 -- Criticism and interpretation , Eliot, T. S. (Thomas Stearns), 1888-1965 -- Criticism and interpretation
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2279 , http://hdl.handle.net/10962/d1007545 , Blake, William, 1757-1827 -- Criticism and interpretation , Eliot, T. S. (Thomas Stearns), 1888-1965 -- Criticism and interpretation
- Description: Many critics resort to explaining readers' experiences of poems like William Blake's Jerusalem and T.S. Eliot's Four Quartets in terms of "spirituality" or "religion". These experiences are broadly defined in this thesis as jouissance (after Roland Barthes' essay The Pleasure of the Text) or "experience qua experience". Critical attempts at the reduction of jouissance into abstract constructs serve merely as stopgap measures by which critics might avoid having to account for the limits of their own rational discourse. These poems, in particular, are deliberately structured to preserve the reader's experience of the poem from reduction to any particular meta-discursive construct, including "the spiritual". Through a broad application of Rezeption-Asthetik principles, this thesis demonstrates how the poems are structured to direct readers' faculties to engage with the hypothetical realm within which jouissance occurs, beyond the rationally abstractable. T.S. Eliot's poetic oeuvre appears to chart his growing confidence in non-rational, pre-critical faculties. Through "The Love Song of J. Alfred Prufrock", The Waste Land, and Four Quartets, Eliot's poetry becomes gradually less prescriptive of the terms to which the experience of his poetry might be reduced. In Four Quartets he finally entrusts readers with a great deal of responsibility for "co-creating" the poem's significance. Like T.S . Eliot, although more consistently throughout his oeuvre, William Blake is similarly concerned with the validation of the reader's subjective interpretative/creative faculties. Blake's Jerusalem is carefully structured on various intertwined levels to rouse and exercise in the reader what the poet calls the "All Glorious Imagination" (Keynes 1972: 679). The jouissance of Jerusalem or Four Quartets is located in the reader's efforts to co-create the significance of the poems. It is only during a direct engagement with this process, rather than in subsequent attempts to abstract it, that the "experience qua experience" may be understood.
- Full Text:
- Date Issued: 2002
Reconciling Western and African philosophy : rationality, culture and communitarianism
- Authors: Vitsha, Xolisa
- Date: 2002
- Subjects: Philosophy, African , Africa -- Intellectual life , Philosophy, Comparative , Philosophy , Communitarianism , Self
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2838 , http://hdl.handle.net/10962/d1003807 , Philosophy, African , Africa -- Intellectual life , Philosophy, Comparative , Philosophy , Communitarianism , Self
- Description: This thesis attempts to reconcile Western and African philosophy with specific reference to the issues of rationality, culture and communitarianism. It also discusses the post-Enlightenment, Western philosophical concept of liberal "atomism" and the primacy of the individual and the emergence of a communitarian critique in response. This thesis intends exploring how Western notions of individuality and the communitarian response can be reconciled with contemporary African philosophy and African communitarian thought in particular. To do this, it is necessary to explore the problem of liberal individualism and how African communitarianism might reinforce the Western communitarian critique. African communitarianism has a processual understanding of personhood that underpins its conception of the Self. In contrast to this view, Western communitarianism has a relational conception of the individual Self. Thus, this thesis argues that African communitarianism has a more profound understanding of the constitution of the Self. To demonstrate these claims, this study discusses notions of rationality which inform each of the philosophical traditions. This will enable a comparative analysis of the above-mentioned philosophical traditions with the intention of uncovering the concepts that provide the platform for their reconciliation.
- Full Text:
- Date Issued: 2002
- Authors: Vitsha, Xolisa
- Date: 2002
- Subjects: Philosophy, African , Africa -- Intellectual life , Philosophy, Comparative , Philosophy , Communitarianism , Self
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2838 , http://hdl.handle.net/10962/d1003807 , Philosophy, African , Africa -- Intellectual life , Philosophy, Comparative , Philosophy , Communitarianism , Self
- Description: This thesis attempts to reconcile Western and African philosophy with specific reference to the issues of rationality, culture and communitarianism. It also discusses the post-Enlightenment, Western philosophical concept of liberal "atomism" and the primacy of the individual and the emergence of a communitarian critique in response. This thesis intends exploring how Western notions of individuality and the communitarian response can be reconciled with contemporary African philosophy and African communitarian thought in particular. To do this, it is necessary to explore the problem of liberal individualism and how African communitarianism might reinforce the Western communitarian critique. African communitarianism has a processual understanding of personhood that underpins its conception of the Self. In contrast to this view, Western communitarianism has a relational conception of the individual Self. Thus, this thesis argues that African communitarianism has a more profound understanding of the constitution of the Self. To demonstrate these claims, this study discusses notions of rationality which inform each of the philosophical traditions. This will enable a comparative analysis of the above-mentioned philosophical traditions with the intention of uncovering the concepts that provide the platform for their reconciliation.
- Full Text:
- Date Issued: 2002
Reengineering the business processes in small, medium and micro enterprises (SMME'S) in order to improve profitability
- Authors: Figg, Malcolm John
- Date: 2002
- Subjects: Reengineering (Management)
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10850 , http://hdl.handle.net/10948/112 , Reengineering (Management)
- Description: The research problem addressed in this study was to identify guidelines to improve business processes that will enhance the ability of Small, Medium, and Micro Enterprises (SMME’s) to be able to operate competitively in local and global markets. Reengineering of business processes (BPR) is necessary because of internal factors such as increasing global competition, increasing domestic competition, new technologies, industry overcapacity, shrinking markets and increasing pressure from suppliers. There are also various external factors that influence the necessity to reengineer business processes. These factors include increasing cost structure, declining profitability, declining sales, low productivity, inadequate employee skills and less efficiency in operations. In order to identify guidelines that will enhance SMME’s performance, questionnaires with relevant questions were used . The findings of the literature survey clearly highlights the specific areas where attention is required for improvements.
- Full Text:
- Date Issued: 2002
- Authors: Figg, Malcolm John
- Date: 2002
- Subjects: Reengineering (Management)
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10850 , http://hdl.handle.net/10948/112 , Reengineering (Management)
- Description: The research problem addressed in this study was to identify guidelines to improve business processes that will enhance the ability of Small, Medium, and Micro Enterprises (SMME’s) to be able to operate competitively in local and global markets. Reengineering of business processes (BPR) is necessary because of internal factors such as increasing global competition, increasing domestic competition, new technologies, industry overcapacity, shrinking markets and increasing pressure from suppliers. There are also various external factors that influence the necessity to reengineer business processes. These factors include increasing cost structure, declining profitability, declining sales, low productivity, inadequate employee skills and less efficiency in operations. In order to identify guidelines that will enhance SMME’s performance, questionnaires with relevant questions were used . The findings of the literature survey clearly highlights the specific areas where attention is required for improvements.
- Full Text:
- Date Issued: 2002
Relationship between temparament and linear body parameters of beef cattle under communal grazing system
- Authors: Nekhofhe, Avhasei Justice
- Date: 2002
- Subjects: Cattle , Grazing
- Language: English
- Type: Thesis , Masters , MTech (Agricultural Management)
- Identifier: vital:10965 , http://hdl.handle.net/10948/113 , Cattle , Grazing
- Description: Introduction : Indigenous cattle are mostly reared where the traditional farming is practiced including Northern Region of South Africa. The majority of farmers own Nguni type of cattle although other breeds are found in the region. They perform well under harsh conditions and they seem to produce better under intensive management. However, communal farmers are becoming aware and interested in indigenous breeds especially Nguni cattle type because of their adaptability. Beef cattle production and research require constant movement and handling of livestock (Erf et al., 1992 & Grandin, 1993). Dipping, castration, branding, ear-tagging and counting is commonly practiced as beef cattle management norms hence dehorning are partly practiced as some of the animals had horns which were disturbing them to pass through crushpens and as a result they increased bruising to other animals. At Matatani and Muledzhi areas animals including calves are packed in the crushpens, counted, weighed and temperament traits were also measured on the scale and this is done in order to document the information for this research and future use. Temperament is a behavioural response of animals as handled by man. It is important to be measured in beef cattle farmers under communal grazing conditions as it reduces farmer’s profit and it makes the stock man’s work unpleasant. Therefore, it is also needs to be improved for the improvement of beef cattle schemes. Management system of communal farmers was not conducive to better quality meat due to horns in some animals which ultimately cause bruising in other animals. However, exotic bulls were bought at random for the improvement of other breed types found in these two areas. The focus of this study is almost in Nguni cattle type managed under communal grazing system. Lastly, the purpose of this study is to determine behavioral response of beef cattle under communal management system at their dipping tanks.
- Full Text:
- Date Issued: 2002
- Authors: Nekhofhe, Avhasei Justice
- Date: 2002
- Subjects: Cattle , Grazing
- Language: English
- Type: Thesis , Masters , MTech (Agricultural Management)
- Identifier: vital:10965 , http://hdl.handle.net/10948/113 , Cattle , Grazing
- Description: Introduction : Indigenous cattle are mostly reared where the traditional farming is practiced including Northern Region of South Africa. The majority of farmers own Nguni type of cattle although other breeds are found in the region. They perform well under harsh conditions and they seem to produce better under intensive management. However, communal farmers are becoming aware and interested in indigenous breeds especially Nguni cattle type because of their adaptability. Beef cattle production and research require constant movement and handling of livestock (Erf et al., 1992 & Grandin, 1993). Dipping, castration, branding, ear-tagging and counting is commonly practiced as beef cattle management norms hence dehorning are partly practiced as some of the animals had horns which were disturbing them to pass through crushpens and as a result they increased bruising to other animals. At Matatani and Muledzhi areas animals including calves are packed in the crushpens, counted, weighed and temperament traits were also measured on the scale and this is done in order to document the information for this research and future use. Temperament is a behavioural response of animals as handled by man. It is important to be measured in beef cattle farmers under communal grazing conditions as it reduces farmer’s profit and it makes the stock man’s work unpleasant. Therefore, it is also needs to be improved for the improvement of beef cattle schemes. Management system of communal farmers was not conducive to better quality meat due to horns in some animals which ultimately cause bruising in other animals. However, exotic bulls were bought at random for the improvement of other breed types found in these two areas. The focus of this study is almost in Nguni cattle type managed under communal grazing system. Lastly, the purpose of this study is to determine behavioral response of beef cattle under communal management system at their dipping tanks.
- Full Text:
- Date Issued: 2002
Removal and recovery of gold and platinum from aqueous solutions utilising the non-viable biomass Asolla filiculoides
- Authors: Antunes, Ana Paula Martins
- Date: 2002
- Subjects: Azolla filiculoides Metal wastes -- Recycling Gold -- Recycling Platinum -- Recycling
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3894 , http://hdl.handle.net/10962/d1003726
- Description: Waste water from the mining industry is generally extremely complex and contains numerous species which influence the adsorption of the metals to any biomass. A variety of factors need to be addressed before treatment is considered viable. It is also beneficial to establish the binding characteristics of the metal of interest to maximise its interaction with the biomass to be utilised. Azalia filiculaides was investigated in the adsorption of gold(III), lead(II), iron(ID), copper(II) and platinum (IV). In batch studies, the optimum biomass and initial gold(III) concentrations were found to be 5 gIL and 8 mgIL respectively. The adsorption of gold(ID) is principally pH-dependent with optimal removal at pH 2. Lead(II), iron(III) and copper(II) did not compete with gold(III) adsorption under equimolar and simulated effluent conditions. Halides, with increasing affinity for gold (chloride < bromide < iodide), can affect gold uptake with the soft base, iodide, exhibiting the most inhibition (25%) and the hard base, chloride, O%. Mercaptoethanol (soft base) showed no interference in gold(III) adsorption while the presence of sulphate (hard base) and sulphite (borderline base) showed that concentrations in excess of 1 0 mM may adversely affect gold(ill) uptake, most likely due to competition for cationic sites on the biomass. Column studies, better suited to high volume treatment, indicated that a flow-rate of 5 mL/min and an initial gold(ill) concentration of 5 mgIL was optimal. Competitive effects between lead, iron, copper and gold again showed little or no interference. The halides, chloride, bromide and iodide, affect gold(ill) uptake similarly to the batch studies, while the bases mercaptoethanol and sulphate minimally affect gold(III) binding with sulphite severely hampering adsorption (70% inhibition). To optimise gold desorption, preliminary batch studies indicated that a ratio of 1:1 of adsorbentdesorbent was optimal, whilst gas purging of thiourea with oxygen, air and nitrogen decreased gold elution in proportion to decreased amounts of oxygen. A series of desorbents were utilised, in column studies, to optimise and determine the speciation of bound gold. The presence of an oxidant with thiourea enhanced desorption greater than 3 fold when compared with thiourea alone. Thiourea desorption studies, aided by the oxidant, suggest that gold is present in the + I and 0 oxidation states. Ultimately thiourea, perchloric acid and hydrochloric acid was found to be the most optimal elutant for gold (J 00% recovery). For selective metal recovery oflead and copper, pre-washing the plant material with water, utilising an acid (0.3 M nitric acid), pumping in an up-flow mode, and recycling the desorbent six times was found to be optimal elutant for gold (J 00% recovery). Cost analysis of utilising elutant versus incinerating the biomass for gold recovery indicated the latter as the most economical. Over a 5 cycle adsorption and desorption series, acid desorption before each adsorption cycle was found to result in greater than 92% desorption for lead and 96% for copper. Gold recovery was 97% with incineration. A preliminary study with gold effluent (Mine C) indicated that nickel and sulphate was removed in batch and column studies. Gold removal was found to be 100% and 4% in batch and column studies respectively. Adsorption of gold in the effluent study was accompanied by the release ofHt. Modifying the plant material with various reagents failed to identify the primary binding sites and the role of polysaccharides, proteins and lipids in gold(ill) uptake. The mode of gold binding is suggested as being initially ionic, this is very rapid, with the interaction of the anionic complex, [AuCI₄]". with the cationic biomass (PH 2). This eventually leads to the displacement of the chloride ligand(s) initiating covalent binding. Spectral studies of the chemical interaction between gold and the representative tannins indicated the protonated hydroxy groups to be responsible. All evidence suggests that the binding mechanisms of gold are not simple. Preliminary adsorption studies of platinum by Azalia filiculaides were conducted. Batch studies indicated that J gIL biomass concentration, initial platinum concentration of 20 mgIL and pH 2 are optimal, while the column studies indicated a flow-rate of! 0 rnL/min and initial platinum concentration of 20 mgIL as optimal. In the platinum effluent study, platinum showed a removal of 23 % and 2 J % for the batch and column studies respectively. Again adsorption was accompanied by //' release. Azalia filiculaides demonstrated its feasibility in the removal of gold and platinum from simulated as well as waste water solutions. Its potential viability as a biosorbent was demonstrated by the high recovery from synthetic solutions of greater than 99% for gold (2-10 mgIL), and greater than 89% for platinum (20 mgIL).
- Full Text:
- Date Issued: 2002
- Authors: Antunes, Ana Paula Martins
- Date: 2002
- Subjects: Azolla filiculoides Metal wastes -- Recycling Gold -- Recycling Platinum -- Recycling
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3894 , http://hdl.handle.net/10962/d1003726
- Description: Waste water from the mining industry is generally extremely complex and contains numerous species which influence the adsorption of the metals to any biomass. A variety of factors need to be addressed before treatment is considered viable. It is also beneficial to establish the binding characteristics of the metal of interest to maximise its interaction with the biomass to be utilised. Azalia filiculaides was investigated in the adsorption of gold(III), lead(II), iron(ID), copper(II) and platinum (IV). In batch studies, the optimum biomass and initial gold(III) concentrations were found to be 5 gIL and 8 mgIL respectively. The adsorption of gold(ID) is principally pH-dependent with optimal removal at pH 2. Lead(II), iron(III) and copper(II) did not compete with gold(III) adsorption under equimolar and simulated effluent conditions. Halides, with increasing affinity for gold (chloride < bromide < iodide), can affect gold uptake with the soft base, iodide, exhibiting the most inhibition (25%) and the hard base, chloride, O%. Mercaptoethanol (soft base) showed no interference in gold(III) adsorption while the presence of sulphate (hard base) and sulphite (borderline base) showed that concentrations in excess of 1 0 mM may adversely affect gold(ill) uptake, most likely due to competition for cationic sites on the biomass. Column studies, better suited to high volume treatment, indicated that a flow-rate of 5 mL/min and an initial gold(ill) concentration of 5 mgIL was optimal. Competitive effects between lead, iron, copper and gold again showed little or no interference. The halides, chloride, bromide and iodide, affect gold(ill) uptake similarly to the batch studies, while the bases mercaptoethanol and sulphate minimally affect gold(III) binding with sulphite severely hampering adsorption (70% inhibition). To optimise gold desorption, preliminary batch studies indicated that a ratio of 1:1 of adsorbentdesorbent was optimal, whilst gas purging of thiourea with oxygen, air and nitrogen decreased gold elution in proportion to decreased amounts of oxygen. A series of desorbents were utilised, in column studies, to optimise and determine the speciation of bound gold. The presence of an oxidant with thiourea enhanced desorption greater than 3 fold when compared with thiourea alone. Thiourea desorption studies, aided by the oxidant, suggest that gold is present in the + I and 0 oxidation states. Ultimately thiourea, perchloric acid and hydrochloric acid was found to be the most optimal elutant for gold (J 00% recovery). For selective metal recovery oflead and copper, pre-washing the plant material with water, utilising an acid (0.3 M nitric acid), pumping in an up-flow mode, and recycling the desorbent six times was found to be optimal elutant for gold (J 00% recovery). Cost analysis of utilising elutant versus incinerating the biomass for gold recovery indicated the latter as the most economical. Over a 5 cycle adsorption and desorption series, acid desorption before each adsorption cycle was found to result in greater than 92% desorption for lead and 96% for copper. Gold recovery was 97% with incineration. A preliminary study with gold effluent (Mine C) indicated that nickel and sulphate was removed in batch and column studies. Gold removal was found to be 100% and 4% in batch and column studies respectively. Adsorption of gold in the effluent study was accompanied by the release ofHt. Modifying the plant material with various reagents failed to identify the primary binding sites and the role of polysaccharides, proteins and lipids in gold(ill) uptake. The mode of gold binding is suggested as being initially ionic, this is very rapid, with the interaction of the anionic complex, [AuCI₄]". with the cationic biomass (PH 2). This eventually leads to the displacement of the chloride ligand(s) initiating covalent binding. Spectral studies of the chemical interaction between gold and the representative tannins indicated the protonated hydroxy groups to be responsible. All evidence suggests that the binding mechanisms of gold are not simple. Preliminary adsorption studies of platinum by Azalia filiculaides were conducted. Batch studies indicated that J gIL biomass concentration, initial platinum concentration of 20 mgIL and pH 2 are optimal, while the column studies indicated a flow-rate of! 0 rnL/min and initial platinum concentration of 20 mgIL as optimal. In the platinum effluent study, platinum showed a removal of 23 % and 2 J % for the batch and column studies respectively. Again adsorption was accompanied by //' release. Azalia filiculaides demonstrated its feasibility in the removal of gold and platinum from simulated as well as waste water solutions. Its potential viability as a biosorbent was demonstrated by the high recovery from synthetic solutions of greater than 99% for gold (2-10 mgIL), and greater than 89% for platinum (20 mgIL).
- Full Text:
- Date Issued: 2002