Editorial
- Schudel, Ingrid J, Le Grange, Lesley, Reddy, Chris
- Authors: Schudel, Ingrid J , Le Grange, Lesley , Reddy, Chris
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/387193 , vital:68214 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/167508"
- Description: The unprecedented levels of human influence on the global enviroment have drawn the attention of scientists to the extent that in 2002, the Nobel Laureate, Paul Crutzen, helped in postulating a new geological epoch named the Anthropocene (Crutzen, 2002). This idea is not new and Crutzen describes an observation by an Italian geologist named Antonio Stoppani who, in 1873, spoke about an 'anthropozoic era'. Stoppani described this era as a 'new telluric force which in power and universality may be compared to the greater forces of earth' (Stoppani, 1873 in Crutzen, 2002).
- Full Text: false
- Date Issued: 2016
- Authors: Schudel, Ingrid J , Le Grange, Lesley , Reddy, Chris
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/387193 , vital:68214 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/167508"
- Description: The unprecedented levels of human influence on the global enviroment have drawn the attention of scientists to the extent that in 2002, the Nobel Laureate, Paul Crutzen, helped in postulating a new geological epoch named the Anthropocene (Crutzen, 2002). This idea is not new and Crutzen describes an observation by an Italian geologist named Antonio Stoppani who, in 1873, spoke about an 'anthropozoic era'. Stoppani described this era as a 'new telluric force which in power and universality may be compared to the greater forces of earth' (Stoppani, 1873 in Crutzen, 2002).
- Full Text: false
- Date Issued: 2016
Education: the transitional challenges of graduation to employment
- Authors: Mkosana, Nkululeko Cautious
- Date: 2016
- Subjects: College graduates -- Employment -- South Africa Education -- Economic aspects -- South Africa Labor supply -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/12198 , vital:27043
- Description: Graduate unemployment, more specifically the continued inability of young people to make a successful transition from institutions of higher learning to labour markets, remains a key concern and one of the most pressing socio-economic issues facing South Africa. Of similar concern, has been the inordinate length of time it takes for graduates (particularly black graduates) to acquire employment. This research study was undertaken in an attempt to understand employment trends among black graduates: its specific aim is to determine, the length of time it takes for black graduates to acquire employment after graduation. As a secondary aim the study also seeks to determine the underlying causes of long-lasting unemployment. The study investigated the employment circumstances involving a sample of 40 graduate participants from Motherwell Township: it was discovered that it took from 1-3 years for the respondents to acquire employment. The study also found that relative to their male counterparts it took much longer for female graduate participants to acquire employment. It also emerged that the type of qualification possessed by the graduates was a determining factor in the likelihood of their gaining employment timeously.
- Full Text:
- Date Issued: 2016
- Authors: Mkosana, Nkululeko Cautious
- Date: 2016
- Subjects: College graduates -- Employment -- South Africa Education -- Economic aspects -- South Africa Labor supply -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/12198 , vital:27043
- Description: Graduate unemployment, more specifically the continued inability of young people to make a successful transition from institutions of higher learning to labour markets, remains a key concern and one of the most pressing socio-economic issues facing South Africa. Of similar concern, has been the inordinate length of time it takes for graduates (particularly black graduates) to acquire employment. This research study was undertaken in an attempt to understand employment trends among black graduates: its specific aim is to determine, the length of time it takes for black graduates to acquire employment after graduation. As a secondary aim the study also seeks to determine the underlying causes of long-lasting unemployment. The study investigated the employment circumstances involving a sample of 40 graduate participants from Motherwell Township: it was discovered that it took from 1-3 years for the respondents to acquire employment. The study also found that relative to their male counterparts it took much longer for female graduate participants to acquire employment. It also emerged that the type of qualification possessed by the graduates was a determining factor in the likelihood of their gaining employment timeously.
- Full Text:
- Date Issued: 2016
Effect of lipid inclusion levels in aquafeed on carcass composition, quality change during storage and nutrient excretion in dusky kob (Argyrosomus japonicus)
- Authors: Ginindza, Nhlanhla Joseph
- Date: 2016
- Subjects: Aquaculture
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5387 , http://hdl.handle.net/10962/d1020854
- Description: Dusky kob, Argyrosomus japonicus, is an aquaculture species in South Africa that is in pilot commercial production. While the major nutrient requirements of the species are known, the advantages of incorporating formulated feeds into the diet of the species has yet to be fully explored. Research on formulated feed composition is required to: minimise input costs; improve the organoleptic properties and meat quality; and minimise nutrient loss, which contributes to environmental pollution. This study sought to test the impact of different lipid levels in aquafeeds fed to dusky kob juveniles by determining: (i) growth performance, feeding efficiency, proximate and fatty acid composition; (ii) chemical changes and shelf-life of refrigerated fish fillets; and (iii) metabolic rates and nitrogen excretion of juvenile dusky kob. And more...
- Full Text:
- Date Issued: 2016
- Authors: Ginindza, Nhlanhla Joseph
- Date: 2016
- Subjects: Aquaculture
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5387 , http://hdl.handle.net/10962/d1020854
- Description: Dusky kob, Argyrosomus japonicus, is an aquaculture species in South Africa that is in pilot commercial production. While the major nutrient requirements of the species are known, the advantages of incorporating formulated feeds into the diet of the species has yet to be fully explored. Research on formulated feed composition is required to: minimise input costs; improve the organoleptic properties and meat quality; and minimise nutrient loss, which contributes to environmental pollution. This study sought to test the impact of different lipid levels in aquafeeds fed to dusky kob juveniles by determining: (i) growth performance, feeding efficiency, proximate and fatty acid composition; (ii) chemical changes and shelf-life of refrigerated fish fillets; and (iii) metabolic rates and nitrogen excretion of juvenile dusky kob. And more...
- Full Text:
- Date Issued: 2016
Effect of Moringa oleifera leaf meal on growth performance, faecal ammonia emissions, carcass characteristics and the quality of meat from broiler chickens
- Authors: Mxunyelwa, Avela,
- Date: 2016
- Subjects: Moringa oleifera Meat -- Quality Broilers (Chickens)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/15034 , vital:40154
- Description: The objective of the study was to determine growth performance, faecal ammonia gas emission, carcass characteristics and physico-chemical meat traits from broilers fed one of the four dietary treatments, containing 0percent, 1percent, 3percent or 5percent Moringa oleifera leaf meal (MOLM) (T1, T2, T3, and T4, respectively). Dietary treatments were formulated to be isonitrogenous and isocaloric for a starter (0-14 days), grower (15-21days) and finisher (22-35 days). A total of 160 day old Cobb 500 broiler chickens, initially weighing an average of 45g were randomly allocated to each of the dietary treatments, each with four replicates, in 16 pens. Feed and water were offered ad libitum. Feed intakes (FI), average daily gain (ADG), body weight gain (BWG) and feed conversion efficiency (FCE) were measured weekly. At the end of the feeding trial, the feed was withdrawn from the birds for 12 hours with water available ad libitum and the birds were slaughtered using standard abattoir procedures. The breast muscle of each carcass was sampled for meat quality analysis. Organ and carcass weights differences were measured. Birds fed with T1 had the highest FI. Birds fed with T4 had the best FCE at day 14, 21 and 35. At day 7 and 35, there were no significant differences in FCE in all the treatments. At 0 to 35 days, faecal ammonia emission decreased (P<0.05) as MOLM concentration and age of birds increased. Moringa fed broilers had the highest body weights in all the periods despite the incorporation level in the diet. The results showed that inclusion of MOLM had a significant effect (P<0.05) on the heart, neck, and head weights but had no significant effect on liver, gizzard, intestine and feet. Broilers fed with T1 had heavier heart, neck and head weights compared to MOLM fed broilers. In terms of carcass traits, MOLM had a significant effect (P<0.05) on wings and thighs but had no significant effect (P>0.05) on breast and drumsticks. Moringa oleifera leaf meal had a significant effect on carcass weights, control diet had heavier weights (1185g ± 28.96) compared to chickens fed with MOLM diets (1121g±28.96, 1070g ± 28.96, 1030g± 28.96). Broilers fed with MOLM had higher values of lightness (L*) and (b*) values (P<0.05) at 45 minutes and 24 hours and no difference was observed in redness (a*) at 45 minutes and 24 hours. The L* values dropped at 24 hours for all the treatments and MOLM fed broilers had the lowest values (46.59 ± 0.76,46 ± 0.76,49 ± 0.76) compared to the control diet (50 ± 0.76). The pH levels were comparable after 24 hours; T2 had the highest pH values (5.95 ± 0.024) compared to other treatments (5.90 ± 0.024, 5.75 ± 0.024, 5.73 ± 0.024). The results of this study demonstrated that even though the FI was reduced in MOLM fed broilers, they efficiently consumed and used nutrients, as a result MOLM fed birds had higher weights and low ammonia concentration throughout the experiment, which may improve the house environment without affecting the quality of meat.
- Full Text:
- Date Issued: 2016
- Authors: Mxunyelwa, Avela,
- Date: 2016
- Subjects: Moringa oleifera Meat -- Quality Broilers (Chickens)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/15034 , vital:40154
- Description: The objective of the study was to determine growth performance, faecal ammonia gas emission, carcass characteristics and physico-chemical meat traits from broilers fed one of the four dietary treatments, containing 0percent, 1percent, 3percent or 5percent Moringa oleifera leaf meal (MOLM) (T1, T2, T3, and T4, respectively). Dietary treatments were formulated to be isonitrogenous and isocaloric for a starter (0-14 days), grower (15-21days) and finisher (22-35 days). A total of 160 day old Cobb 500 broiler chickens, initially weighing an average of 45g were randomly allocated to each of the dietary treatments, each with four replicates, in 16 pens. Feed and water were offered ad libitum. Feed intakes (FI), average daily gain (ADG), body weight gain (BWG) and feed conversion efficiency (FCE) were measured weekly. At the end of the feeding trial, the feed was withdrawn from the birds for 12 hours with water available ad libitum and the birds were slaughtered using standard abattoir procedures. The breast muscle of each carcass was sampled for meat quality analysis. Organ and carcass weights differences were measured. Birds fed with T1 had the highest FI. Birds fed with T4 had the best FCE at day 14, 21 and 35. At day 7 and 35, there were no significant differences in FCE in all the treatments. At 0 to 35 days, faecal ammonia emission decreased (P<0.05) as MOLM concentration and age of birds increased. Moringa fed broilers had the highest body weights in all the periods despite the incorporation level in the diet. The results showed that inclusion of MOLM had a significant effect (P<0.05) on the heart, neck, and head weights but had no significant effect on liver, gizzard, intestine and feet. Broilers fed with T1 had heavier heart, neck and head weights compared to MOLM fed broilers. In terms of carcass traits, MOLM had a significant effect (P<0.05) on wings and thighs but had no significant effect (P>0.05) on breast and drumsticks. Moringa oleifera leaf meal had a significant effect on carcass weights, control diet had heavier weights (1185g ± 28.96) compared to chickens fed with MOLM diets (1121g±28.96, 1070g ± 28.96, 1030g± 28.96). Broilers fed with MOLM had higher values of lightness (L*) and (b*) values (P<0.05) at 45 minutes and 24 hours and no difference was observed in redness (a*) at 45 minutes and 24 hours. The L* values dropped at 24 hours for all the treatments and MOLM fed broilers had the lowest values (46.59 ± 0.76,46 ± 0.76,49 ± 0.76) compared to the control diet (50 ± 0.76). The pH levels were comparable after 24 hours; T2 had the highest pH values (5.95 ± 0.024) compared to other treatments (5.90 ± 0.024, 5.75 ± 0.024, 5.73 ± 0.024). The results of this study demonstrated that even though the FI was reduced in MOLM fed broilers, they efficiently consumed and used nutrients, as a result MOLM fed birds had higher weights and low ammonia concentration throughout the experiment, which may improve the house environment without affecting the quality of meat.
- Full Text:
- Date Issued: 2016
Effect of organisational policies on school management teams' job performance at Maluti District, Eastern Cape , South Africa
- Authors: Leboea, Paulos Dipholo
- Date: 2016
- Subjects: School management teams Total quality management in higher education -- South Africa -- Eastern Cape Performance standards -- South Africa --Eastern Cape
- Language: English
- Type: Thesis , Doctoral , Degree
- Identifier: http://hdl.handle.net/10353/5315 , vital:29188
- Description: Most school management teams (SMTs) do not do their tasks either due to lack of time or inability to fulfil this obligation. Should this be true for South African schools, it would reflect negatively on the SMT job performance. This led to undertaking research in order to ascertain the fit between organisational policies of induction, mentoring, curriculum assessment training and curriculum supervision and the SMT job performance by way of establishing the effect of organisation policy on SMTs’ job performance. The research adopted a descriptive survey research design of the correlational type. Two sets of questionnaires, one for independent variables and the other for the dependent variable, were used to elicit information from the respondents. Some of the findings show that aspiring SMT members need some training so as to know what will be expected of them to do once they get selected as SMT members. It was further proven that common tests that are normally set at the provincial and district and/or school based levels are invariably not of the standard that the Department of Basic Education (DBE) prescribes nationally. The foregoing led to the conclusion that the SMT job practice is invariably not informed by the relevant organisational policies. Hence a cascade model of SMT training is recommended, as is the notion that training toward organisational policies under review should be done cohesively.
- Full Text:
- Date Issued: 2016
- Authors: Leboea, Paulos Dipholo
- Date: 2016
- Subjects: School management teams Total quality management in higher education -- South Africa -- Eastern Cape Performance standards -- South Africa --Eastern Cape
- Language: English
- Type: Thesis , Doctoral , Degree
- Identifier: http://hdl.handle.net/10353/5315 , vital:29188
- Description: Most school management teams (SMTs) do not do their tasks either due to lack of time or inability to fulfil this obligation. Should this be true for South African schools, it would reflect negatively on the SMT job performance. This led to undertaking research in order to ascertain the fit between organisational policies of induction, mentoring, curriculum assessment training and curriculum supervision and the SMT job performance by way of establishing the effect of organisation policy on SMTs’ job performance. The research adopted a descriptive survey research design of the correlational type. Two sets of questionnaires, one for independent variables and the other for the dependent variable, were used to elicit information from the respondents. Some of the findings show that aspiring SMT members need some training so as to know what will be expected of them to do once they get selected as SMT members. It was further proven that common tests that are normally set at the provincial and district and/or school based levels are invariably not of the standard that the Department of Basic Education (DBE) prescribes nationally. The foregoing led to the conclusion that the SMT job practice is invariably not informed by the relevant organisational policies. Hence a cascade model of SMT training is recommended, as is the notion that training toward organisational policies under review should be done cohesively.
- Full Text:
- Date Issued: 2016
Effect of organisational policies on school management teams' job performance at Maluti District, Eastern Cape , South Africa
- Authors: Leboea, Paulos Dipholo
- Date: 2016
- Subjects: School management teams School management and organization -- South Africa -- Eastern Cape Total quality management in higher education -- South Africa -- Eastern Cape Performance -- Management
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/2293 , vital:27748
- Description: Most school management teams (SMTs) do not do their tasks either due to lack of time or inability to fulfil this obligation. Should this be true for South African schools, it would reflect negatively on the SMT job performance. This led to undertaking research in order to ascertain the fit between organisational policies of induction, mentoring, curriculum assessment training and curriculum supervision and the SMT job performance by way of establishing the effect of organisation policy on SMTs’ job performance. The research adopted a descriptive survey research design of the correlational type. Two sets of questionnaires, one for independent variables and the other for the dependent variable, were used to elicit information from the respondents. Some of the findings show that aspiring SMT members need some training so as to know what will be expected of them to do once they get selected as SMT members. It was further proven that common tests that are normally set at the provincial and district and/or school based levels are invariably not of the standard that the Department of Basic Education (DBE) prescribes nationally. The foregoing led to the conclusion that the SMT job practice is invariably not informed by the relevant organisational policies. Hence a cascade model of SMT training is recommended, as is the notion that training toward organisational policies under review should be done cohesively.
- Full Text:
- Date Issued: 2016
- Authors: Leboea, Paulos Dipholo
- Date: 2016
- Subjects: School management teams School management and organization -- South Africa -- Eastern Cape Total quality management in higher education -- South Africa -- Eastern Cape Performance -- Management
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/2293 , vital:27748
- Description: Most school management teams (SMTs) do not do their tasks either due to lack of time or inability to fulfil this obligation. Should this be true for South African schools, it would reflect negatively on the SMT job performance. This led to undertaking research in order to ascertain the fit between organisational policies of induction, mentoring, curriculum assessment training and curriculum supervision and the SMT job performance by way of establishing the effect of organisation policy on SMTs’ job performance. The research adopted a descriptive survey research design of the correlational type. Two sets of questionnaires, one for independent variables and the other for the dependent variable, were used to elicit information from the respondents. Some of the findings show that aspiring SMT members need some training so as to know what will be expected of them to do once they get selected as SMT members. It was further proven that common tests that are normally set at the provincial and district and/or school based levels are invariably not of the standard that the Department of Basic Education (DBE) prescribes nationally. The foregoing led to the conclusion that the SMT job practice is invariably not informed by the relevant organisational policies. Hence a cascade model of SMT training is recommended, as is the notion that training toward organisational policies under review should be done cohesively.
- Full Text:
- Date Issued: 2016
Effect of phosphorus application on dry matter yield and nutrient content of Mucuna Pruriens (L) in Alice
- Authors: Tshwati, Nolubabalo
- Date: 2016
- Subjects: Legumes Phosphorus Fertilizers
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12326 , vital:39253
- Description: The use of herbaceous legumes such as Mucuna (Mucuna pruriens) can assist to recapitalize soil fertility depletion and improve livestock productivity in the small holder farming sector of South Africa. The objective of the study was to investigate the effect of phosphorus fertilizer application (0, 20, 40 and 60 kg P/ha) on the dry matter yield and nutritive value of Mucuna pruriens. The study was conducted at University of Fort Hare Research farm in Alice, South Africa. The research design was a randomized complete block design with three replicates per treatment. Data collection included biomass production and nutrient content of Mucuna pruriens. The forage legume was harvested at flowering stage of growth and analysed for chemical composition. The results showed that with the application of 60 kg P/ha Mucuna had the highest (P < 0.05) fresh and dry matter yield of 19.58 kg/ha and 5.41 kg/ha, respectively compared to other treatments. However, all the other treatments differed from one another. Similarly, the fresh stem and leaf fractions yield and their dry matter yields showed the same trend with application of 60 kg P/ha having the greatest yield compared to the other treatments. Nevertheless, all the treatments differed (P<0.05) from one another with P0 having the least yields. The leaf to stem ratio did not show any significant (P>0.05) difference among all the treatments ranging from 1.44 to 1.62 in fresh forage and ranging from 1.31 to 1.50 in the dry forage. In terms of dry matter content, the control treatment had the highest dry matter content of 37.78percent, however, all the other treatments did not differ significantly (P < 0.05) from each other. There was no significant effect of P application (P > 0.05) in terms of ash, EE, ADF, CP, Ca, Mg, K, Na, P, Zn, Cu, Mn and Fe of the whole plant forage among the treatments. The application of 40 kg P/ha fertilizer significantly (P < 0.05) increased the NDF (51.16percent) of the whole plant of Mucuna compared to the other treatments which did not differ (p>0.05) among themselves. Within the stem fraction there were no significant (P > 0.05) differences among the treatments for the ash, EE, ADF, NDF, and CP, hemicellulose, Ca, Mg, K, P, Zn, Cu, Mn and Fe contents. However, the application of 40 kg P/ha fertilizer significantly (P < 0.05) increased the Na (0.05percent) content of the Mucuna stem fraction. In the leaf fraction of Mucuna there was no significant (P > 0.05) differences in terms of ash, EE, ADF, NDF, CP, hemicellulose, Ca, K, P, Zn, Cu, Mn and Fe among the treatments. However, the application of 20 kg P/ha fertilizer significantly (P < 0.05) increased the Mg (0.52percent) of the Mucuna leaves compared to the other treatments. Therefore the study has shown that increase in P application (60 kg P/ha) has no major effect in the nutrient content of Mucuna. Furthermore, it is recommended that Mucuna can be grown as a protein supplement, based on the CP content values that were recorded in this study and to provide maintenance requirements for ruminants. It was therefore concluded that phosphorus fertilization particularly 60 kg P/ha is necessary and required for optimum growth of Mucuna pruriens in order to increase forage yield. Based on the nutrient content result it was concluded that there was no effect of P fertilizer application levels on the nutrient content of Mucuna pruriens in Alice.
- Full Text:
- Date Issued: 2016
- Authors: Tshwati, Nolubabalo
- Date: 2016
- Subjects: Legumes Phosphorus Fertilizers
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12326 , vital:39253
- Description: The use of herbaceous legumes such as Mucuna (Mucuna pruriens) can assist to recapitalize soil fertility depletion and improve livestock productivity in the small holder farming sector of South Africa. The objective of the study was to investigate the effect of phosphorus fertilizer application (0, 20, 40 and 60 kg P/ha) on the dry matter yield and nutritive value of Mucuna pruriens. The study was conducted at University of Fort Hare Research farm in Alice, South Africa. The research design was a randomized complete block design with three replicates per treatment. Data collection included biomass production and nutrient content of Mucuna pruriens. The forage legume was harvested at flowering stage of growth and analysed for chemical composition. The results showed that with the application of 60 kg P/ha Mucuna had the highest (P < 0.05) fresh and dry matter yield of 19.58 kg/ha and 5.41 kg/ha, respectively compared to other treatments. However, all the other treatments differed from one another. Similarly, the fresh stem and leaf fractions yield and their dry matter yields showed the same trend with application of 60 kg P/ha having the greatest yield compared to the other treatments. Nevertheless, all the treatments differed (P<0.05) from one another with P0 having the least yields. The leaf to stem ratio did not show any significant (P>0.05) difference among all the treatments ranging from 1.44 to 1.62 in fresh forage and ranging from 1.31 to 1.50 in the dry forage. In terms of dry matter content, the control treatment had the highest dry matter content of 37.78percent, however, all the other treatments did not differ significantly (P < 0.05) from each other. There was no significant effect of P application (P > 0.05) in terms of ash, EE, ADF, CP, Ca, Mg, K, Na, P, Zn, Cu, Mn and Fe of the whole plant forage among the treatments. The application of 40 kg P/ha fertilizer significantly (P < 0.05) increased the NDF (51.16percent) of the whole plant of Mucuna compared to the other treatments which did not differ (p>0.05) among themselves. Within the stem fraction there were no significant (P > 0.05) differences among the treatments for the ash, EE, ADF, NDF, and CP, hemicellulose, Ca, Mg, K, P, Zn, Cu, Mn and Fe contents. However, the application of 40 kg P/ha fertilizer significantly (P < 0.05) increased the Na (0.05percent) content of the Mucuna stem fraction. In the leaf fraction of Mucuna there was no significant (P > 0.05) differences in terms of ash, EE, ADF, NDF, CP, hemicellulose, Ca, K, P, Zn, Cu, Mn and Fe among the treatments. However, the application of 20 kg P/ha fertilizer significantly (P < 0.05) increased the Mg (0.52percent) of the Mucuna leaves compared to the other treatments. Therefore the study has shown that increase in P application (60 kg P/ha) has no major effect in the nutrient content of Mucuna. Furthermore, it is recommended that Mucuna can be grown as a protein supplement, based on the CP content values that were recorded in this study and to provide maintenance requirements for ruminants. It was therefore concluded that phosphorus fertilization particularly 60 kg P/ha is necessary and required for optimum growth of Mucuna pruriens in order to increase forage yield. Based on the nutrient content result it was concluded that there was no effect of P fertilizer application levels on the nutrient content of Mucuna pruriens in Alice.
- Full Text:
- Date Issued: 2016
Effects of frequent changes in curriculum on effective teaching and learning for creating safe, caring and child-friendly schools : a South African case study
- Authors: Makwarela, Mawela Convince
- Date: 2016
- Subjects: School discipline--South Africa School violence--South Africa School management and organization--South Africa
- Language: English
- Type: Thesis , Doctoral , Education
- Identifier: http://hdl.handle.net/10353/15594 , vital:40481
- Description: South Africa‟s government strategy for Child Protection Programmes is the pre-requisite that plans to articulate its work on school learner protection as a distinct area of programmatic intervention. Hence, this study explores an assessment of the implementation of DoE and UNICEF guidelines for creating safe, caring and child-friendly schools. A sequential mixed method approach was used in this study; both questionnaires and interviews were used. The design allows using both quantitative and qualitative data collection methods to elicit implicit and explicit information from the same case through pattern-matching; a technique linking several pieces when a holistic and in-depth investigation is required. The sample of the study consisted of 24 school principals, 24 HoDs, 24 SGB members, 24 educators, 24 educators‟ union members and 24 learners who were conveniently selected from 24 secondary schools across Vhembe District. Survey data were obtained from school principals, HoDs, SGB members, educators, educators‟ union members and learners regarding the ways and degree to which participants are involved in school incidents, decision-making processes, and their own experiences regarding safe, caring and child-friendly schools. In terms of data analysis, validation indicates concurrent and construct validity obtained by combining participant‟s responses from interviews and self-report questionnaires based on experiences of incidents from their schools. Statistically significant results point the way to validating the approaches taken as best practices. The findings reveals among others that the factors contributing to learner aggression include family factors, environmental factors and school-related factors, whilst the most common forms of learner incidents in schools are verbal violence, physical violence and bullying. The results also indicate that a safe school climate is not enough for learners to speak freely and report unwanted sexual experiences. The study concludes with the role that the school, parents and the Department of Education can play in addressing learner problems in schools.
- Full Text:
- Date Issued: 2016
- Authors: Makwarela, Mawela Convince
- Date: 2016
- Subjects: School discipline--South Africa School violence--South Africa School management and organization--South Africa
- Language: English
- Type: Thesis , Doctoral , Education
- Identifier: http://hdl.handle.net/10353/15594 , vital:40481
- Description: South Africa‟s government strategy for Child Protection Programmes is the pre-requisite that plans to articulate its work on school learner protection as a distinct area of programmatic intervention. Hence, this study explores an assessment of the implementation of DoE and UNICEF guidelines for creating safe, caring and child-friendly schools. A sequential mixed method approach was used in this study; both questionnaires and interviews were used. The design allows using both quantitative and qualitative data collection methods to elicit implicit and explicit information from the same case through pattern-matching; a technique linking several pieces when a holistic and in-depth investigation is required. The sample of the study consisted of 24 school principals, 24 HoDs, 24 SGB members, 24 educators, 24 educators‟ union members and 24 learners who were conveniently selected from 24 secondary schools across Vhembe District. Survey data were obtained from school principals, HoDs, SGB members, educators, educators‟ union members and learners regarding the ways and degree to which participants are involved in school incidents, decision-making processes, and their own experiences regarding safe, caring and child-friendly schools. In terms of data analysis, validation indicates concurrent and construct validity obtained by combining participant‟s responses from interviews and self-report questionnaires based on experiences of incidents from their schools. Statistically significant results point the way to validating the approaches taken as best practices. The findings reveals among others that the factors contributing to learner aggression include family factors, environmental factors and school-related factors, whilst the most common forms of learner incidents in schools are verbal violence, physical violence and bullying. The results also indicate that a safe school climate is not enough for learners to speak freely and report unwanted sexual experiences. The study concludes with the role that the school, parents and the Department of Education can play in addressing learner problems in schools.
- Full Text:
- Date Issued: 2016
Effects of grazing and housing management systems on greenhouse gas emissions, blood profiles and meat quality of Nguni goats
- Authors: Tapiwa, Chikwanda Allen
- Date: 2016
- Subjects: Goats Goats -- Feeding and feeds Greenhouse gas mitigation , Grazing -- Environmental aspects
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/2314 , vital:27752
- Description: The broad objective of this study was to evaluate the effects of grazing and housing management systems on greenhouse gas emissions, blood profiles and meat quality of Nguni goats. A total of 64 castrated Nguni goats were used and a housing structure was designed to accommodate the goats as well as evaluate effects of type of floor on greenhouse gases, meat quality, blood metabolites and fatty acid profiles. In the first experiment: Forty-eight castrated Nguni goats, at 6-7 months old were used for herding (H) or tethering (T) management systems and randomly allocated to pens with earth (E) or slatted (S) floors. Gas sampling was done using static chambers and analysed using a SRI 8610C gas chromatography machine. The highest CH4 fluxes were from the manure of herded goats on earth floors (HE). The highest CO2 fluxes were from manure of herded goats that were housed on slatted floors (HS): The highest N2O fluxes were from the manure of tethered goats that were sheltered on slatted floors (TS). It was concluded from the first experiment that goat manure is an important source of GHG that is influenced by grazing and floor type management systems. The second experiment was done to evaluate greenhouse gas (GHG) emission from disused (DP) vs occupied goat pens (OP) with earth (EF) or slatted (SF) floors. Eight previously occupied pens were used in this study. Sixteen goats were randomly put in the pens labelled occupied pens with earth floors (OPEF) and occupied pens with slatted floors (OPSF) resulting in four goats per OP. There were month by pen use; month by floor type; and use by floor type interaction effects (P < 0.05) on CH4 production. Floor type, use (DP vs OP) and month affected (P < 0.05) CH4 production. Manure on earth floors of occupied pens (OPEF) emitted the highest (P < 0.05) methane followed by earth floors of disused pens (DPEF). The least CH4 was emitted from DPSF. There was pen use (DP vs OP) by floor type interaction effect (P < 0.05) on CO2 emission. Floor type and pen use affected (P < 0.05) CO2 production. Manure in occupied pens with slatted floors (OPSF) produced the highest CO2 and the least CO2 was from disused pens with slatted floors (DPSF). Floor type and month influenced (P < 0.05) N2O production. It was concluded that continued use of goat pens increased GHG emissions. However, disused goat pens with manure remain an important source of GHG as they continued to emit quantifiable levels of CH4, CO2 and N2O. The third experiment was done to determine the effects of grazing and housing management systems on the concentrations of blood metabolites, activity of creatine kinase, body weight (BW), body condition score (BCS) and carcass characteristics using 48 castrated Nguni goats. Tethered goats had higher (P<0.05): urea, creatinine, total protein, globulin concentrations and more activity of CK than herded goats. On the other hand, herded goats had higher (P<0.05) plasma glucose (H: 3.39±0.020 vs T: 3.23±0.020 mmol/L), serum albumin (H: 15.30±0.147 vs T: 14.82±0.144 g/L) concentration. It was concluded that serum concentrations of all the metabolites and the activity of CK were sensitive to grazing system. Herding of goats promoted more glucose concentration and preservation of muscle protein and hence superior body weights and BCS than tethered goats. The fourth experiment was done to determine the effects of grazing and housing management systems on the activity of creatine kinase (CK) and cortisol concentration, and chevon quality. Further, the effect of muscle type [Muscularis longissimus thoracis et. Lumborum (LTL) and triceps brachii (TB)] on chevon quality was also investigated. Forty eight castrated Nguni goats aged 6- 7 months were randomly allocated to tethering (n=24) and herding (n=24) treatments. Floor type affected meat (P<0.05) pH24. Tethered goats had higher (P < 0.05) L* and CL percent than herded goats. Muscle type had a significant influence (P < 0.05) on a*, WBSF and pH. It was observed and concluded that T resulted in higher L* and more CL percent whilst SF lowered the pH24 of chevon; at the same time meat from the TB muscle was more tender, despite having a higher pH24 and more CL percent relative to LTH cuts. The fifth experiment was done to determine the effect of grazing and floor type on fatty acid composition of chevon from tethered and herded Nguni goats. Floor type had no effect on fatty acid composition. Oleic, stearic, palmitic and linoleic were the major fatty acids. Chevon from tethered goats had higher (P < 0.05) proportions of long chain polyunsaturated fatty acids (PUFAs): eicosapentaenoic, docosapentaenoic, docosahexaenoic, conjugated linoleic acid (CLA) and more total SFA, total PUFA, total Omega- 6 and total omega 3 fatty acids than herded goats. On the other hand, chevon from herded goats had more (P < 0.05) C18:1c9, C18:2t9, 12 (n-6), C20:3c11, 14, 17 (n-3) and total MUFA than tethered goats. However, there was no difference (P > 0.05) in the PUFA: SFA and n-6/n-3 fatty acid ratios between the herded and tethered goats. It was concluded that tethering promoted higher proportions of beneficial PUFAs which were more in TB than LTH muscle. The overall conclusions from the whole study were that goat manure is an important source of GHG with high CH4 being emitted from earth floors of herded goats. High CO2 and N2O are emitted from SF of herded and tethered goats, respectively. There were no major differences in meat quality between herded and tethered goats. However, herding promoted more live weight gain than tethering. On the other hand, tethering promoted more beneficial fatty acids. Therefore depending on the objective of the enterprise, smallholder farmers can safely tether or herd their goats. Further, there is need to develop technologies to harness CH4 from goat manure.
- Full Text:
- Date Issued: 2016
- Authors: Tapiwa, Chikwanda Allen
- Date: 2016
- Subjects: Goats Goats -- Feeding and feeds Greenhouse gas mitigation , Grazing -- Environmental aspects
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/2314 , vital:27752
- Description: The broad objective of this study was to evaluate the effects of grazing and housing management systems on greenhouse gas emissions, blood profiles and meat quality of Nguni goats. A total of 64 castrated Nguni goats were used and a housing structure was designed to accommodate the goats as well as evaluate effects of type of floor on greenhouse gases, meat quality, blood metabolites and fatty acid profiles. In the first experiment: Forty-eight castrated Nguni goats, at 6-7 months old were used for herding (H) or tethering (T) management systems and randomly allocated to pens with earth (E) or slatted (S) floors. Gas sampling was done using static chambers and analysed using a SRI 8610C gas chromatography machine. The highest CH4 fluxes were from the manure of herded goats on earth floors (HE). The highest CO2 fluxes were from manure of herded goats that were housed on slatted floors (HS): The highest N2O fluxes were from the manure of tethered goats that were sheltered on slatted floors (TS). It was concluded from the first experiment that goat manure is an important source of GHG that is influenced by grazing and floor type management systems. The second experiment was done to evaluate greenhouse gas (GHG) emission from disused (DP) vs occupied goat pens (OP) with earth (EF) or slatted (SF) floors. Eight previously occupied pens were used in this study. Sixteen goats were randomly put in the pens labelled occupied pens with earth floors (OPEF) and occupied pens with slatted floors (OPSF) resulting in four goats per OP. There were month by pen use; month by floor type; and use by floor type interaction effects (P < 0.05) on CH4 production. Floor type, use (DP vs OP) and month affected (P < 0.05) CH4 production. Manure on earth floors of occupied pens (OPEF) emitted the highest (P < 0.05) methane followed by earth floors of disused pens (DPEF). The least CH4 was emitted from DPSF. There was pen use (DP vs OP) by floor type interaction effect (P < 0.05) on CO2 emission. Floor type and pen use affected (P < 0.05) CO2 production. Manure in occupied pens with slatted floors (OPSF) produced the highest CO2 and the least CO2 was from disused pens with slatted floors (DPSF). Floor type and month influenced (P < 0.05) N2O production. It was concluded that continued use of goat pens increased GHG emissions. However, disused goat pens with manure remain an important source of GHG as they continued to emit quantifiable levels of CH4, CO2 and N2O. The third experiment was done to determine the effects of grazing and housing management systems on the concentrations of blood metabolites, activity of creatine kinase, body weight (BW), body condition score (BCS) and carcass characteristics using 48 castrated Nguni goats. Tethered goats had higher (P<0.05): urea, creatinine, total protein, globulin concentrations and more activity of CK than herded goats. On the other hand, herded goats had higher (P<0.05) plasma glucose (H: 3.39±0.020 vs T: 3.23±0.020 mmol/L), serum albumin (H: 15.30±0.147 vs T: 14.82±0.144 g/L) concentration. It was concluded that serum concentrations of all the metabolites and the activity of CK were sensitive to grazing system. Herding of goats promoted more glucose concentration and preservation of muscle protein and hence superior body weights and BCS than tethered goats. The fourth experiment was done to determine the effects of grazing and housing management systems on the activity of creatine kinase (CK) and cortisol concentration, and chevon quality. Further, the effect of muscle type [Muscularis longissimus thoracis et. Lumborum (LTL) and triceps brachii (TB)] on chevon quality was also investigated. Forty eight castrated Nguni goats aged 6- 7 months were randomly allocated to tethering (n=24) and herding (n=24) treatments. Floor type affected meat (P<0.05) pH24. Tethered goats had higher (P < 0.05) L* and CL percent than herded goats. Muscle type had a significant influence (P < 0.05) on a*, WBSF and pH. It was observed and concluded that T resulted in higher L* and more CL percent whilst SF lowered the pH24 of chevon; at the same time meat from the TB muscle was more tender, despite having a higher pH24 and more CL percent relative to LTH cuts. The fifth experiment was done to determine the effect of grazing and floor type on fatty acid composition of chevon from tethered and herded Nguni goats. Floor type had no effect on fatty acid composition. Oleic, stearic, palmitic and linoleic were the major fatty acids. Chevon from tethered goats had higher (P < 0.05) proportions of long chain polyunsaturated fatty acids (PUFAs): eicosapentaenoic, docosapentaenoic, docosahexaenoic, conjugated linoleic acid (CLA) and more total SFA, total PUFA, total Omega- 6 and total omega 3 fatty acids than herded goats. On the other hand, chevon from herded goats had more (P < 0.05) C18:1c9, C18:2t9, 12 (n-6), C20:3c11, 14, 17 (n-3) and total MUFA than tethered goats. However, there was no difference (P > 0.05) in the PUFA: SFA and n-6/n-3 fatty acid ratios between the herded and tethered goats. It was concluded that tethering promoted higher proportions of beneficial PUFAs which were more in TB than LTH muscle. The overall conclusions from the whole study were that goat manure is an important source of GHG with high CH4 being emitted from earth floors of herded goats. High CO2 and N2O are emitted from SF of herded and tethered goats, respectively. There were no major differences in meat quality between herded and tethered goats. However, herding promoted more live weight gain than tethering. On the other hand, tethering promoted more beneficial fatty acids. Therefore depending on the objective of the enterprise, smallholder farmers can safely tether or herd their goats. Further, there is need to develop technologies to harness CH4 from goat manure.
- Full Text:
- Date Issued: 2016
Effects of lethal management on black-backed jackal population structure and source-sink dynamics
- Authors: Minnie, Liaan
- Date: 2016
- Subjects: Black-backed jackal Carnivorous animals
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/12658 , vital:27104
- Description: Lethal carnivore management, aimed at reducing carnivore impacts, threatens the persistence of carnivores globally. The effects of killing carnivores will depend on their life histories and social structures. Smaller canids, like black-backed jackals (Canis mesomelas), are highly adaptable and display variable population-level responses to mortality sources, which may contribute to their success in fragmented landscapes. Jackals, the dominant predator of livestock in South Africa, are widely hunted to reduce this predation. This hunting is heterogeneous across the landscape, focussed on livestock and game farms, with nature reserves acting as refuges. The aim of this research was to investigate the ecology and population dynamics of jackals in response to heterogeneous anthropogenic mortality. I hypothesized that the spatial variation in hunting results in the formation of a source-sink population structure, which contributes to the persistence of jackals. I addressed this hypothesis by evaluating two criteria, essential for the formation of a source-sink system in larger mammals. Firstly, I confirm that hunting pressures result in the formation of distinct subpopulations with asymmetrical dispersal (i.e. compensatory immigration) from unhunted reserves to neighbouring hunted farms. Secondly, I show that jackal subpopulation display asynchronous demographics, with farm populations displaying a relatively younger age structure and an associated increase in reproductive output (i.e. compensatory reproduction). This confirms the formation of a hunting-induced source-sink system. additionally, I show that jackals have a catholic diet, which confers a level of adaptability to direct (anthropogenic mortality, prey provisioning) and indirect (alteration in prey base) habitat modifications. This dietary flexibility allows jackals to obtain the appropriate resources to achieve reproductive condition. The relatively better body condition of younger jackals in sink habitats allows for compensatory reproduction which contributes to the success of jackals on hunted farms. Based on my findings, I hypothesize that the compensatory life history responses of jackals to anthropogenic mortality may be ascribed to two interconnected mechanism. Dispersal is presumably driven by density-dependent interference competition, as dominant territorial pairs outcompete subordinates in high-density reserve areas, forcing them to disperse onto low-density farms (i.e. ideal despotic model). Additionally, farms likely represent attractive habitats, owing to a reduction in conspecifics and a concomitant increase in resource availability (including anthropogenic resource provisioning). Therefore, dispersing subordinates presumably select for farms which are perceived as good quality habitats, as the high risks of anthropogenic mortality cannot be perceived by dispersing individuals. This results in the formation of an attractive sink or ecological trap. These compensatory processes will continue to counter population management actions as long as recruitment from unmanaged areas persists. This hypothesis provides a conceptual framework for future research directions in understanding jackal persistence and management (i.e. specifically focussing on controlling dispersal) of jackal populations.
- Full Text:
- Date Issued: 2016
- Authors: Minnie, Liaan
- Date: 2016
- Subjects: Black-backed jackal Carnivorous animals
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/12658 , vital:27104
- Description: Lethal carnivore management, aimed at reducing carnivore impacts, threatens the persistence of carnivores globally. The effects of killing carnivores will depend on their life histories and social structures. Smaller canids, like black-backed jackals (Canis mesomelas), are highly adaptable and display variable population-level responses to mortality sources, which may contribute to their success in fragmented landscapes. Jackals, the dominant predator of livestock in South Africa, are widely hunted to reduce this predation. This hunting is heterogeneous across the landscape, focussed on livestock and game farms, with nature reserves acting as refuges. The aim of this research was to investigate the ecology and population dynamics of jackals in response to heterogeneous anthropogenic mortality. I hypothesized that the spatial variation in hunting results in the formation of a source-sink population structure, which contributes to the persistence of jackals. I addressed this hypothesis by evaluating two criteria, essential for the formation of a source-sink system in larger mammals. Firstly, I confirm that hunting pressures result in the formation of distinct subpopulations with asymmetrical dispersal (i.e. compensatory immigration) from unhunted reserves to neighbouring hunted farms. Secondly, I show that jackal subpopulation display asynchronous demographics, with farm populations displaying a relatively younger age structure and an associated increase in reproductive output (i.e. compensatory reproduction). This confirms the formation of a hunting-induced source-sink system. additionally, I show that jackals have a catholic diet, which confers a level of adaptability to direct (anthropogenic mortality, prey provisioning) and indirect (alteration in prey base) habitat modifications. This dietary flexibility allows jackals to obtain the appropriate resources to achieve reproductive condition. The relatively better body condition of younger jackals in sink habitats allows for compensatory reproduction which contributes to the success of jackals on hunted farms. Based on my findings, I hypothesize that the compensatory life history responses of jackals to anthropogenic mortality may be ascribed to two interconnected mechanism. Dispersal is presumably driven by density-dependent interference competition, as dominant territorial pairs outcompete subordinates in high-density reserve areas, forcing them to disperse onto low-density farms (i.e. ideal despotic model). Additionally, farms likely represent attractive habitats, owing to a reduction in conspecifics and a concomitant increase in resource availability (including anthropogenic resource provisioning). Therefore, dispersing subordinates presumably select for farms which are perceived as good quality habitats, as the high risks of anthropogenic mortality cannot be perceived by dispersing individuals. This results in the formation of an attractive sink or ecological trap. These compensatory processes will continue to counter population management actions as long as recruitment from unmanaged areas persists. This hypothesis provides a conceptual framework for future research directions in understanding jackal persistence and management (i.e. specifically focussing on controlling dispersal) of jackal populations.
- Full Text:
- Date Issued: 2016
Effects of pluronic silica nanoparticles on the photophysical and photodynamic therapy behavior of triphenyl-p-phenoxy benzoic acid metalloporphyrins
- Managa, Muthumuni, Britton, Jonathan, Prinsloo, Earl, Nyokong, Tebello
- Authors: Managa, Muthumuni , Britton, Jonathan , Prinsloo, Earl , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/239698 , vital:50756 , xlink:href="https://doi.org/10.1080/00958972.2016.1236372"
- Description: 5, 10, 15, Triphenyl-20-p-phenoxy benzoic acid porphyrins (P) containing Zn (ZnP), Ga (GaP), and Si (SiP) were synthesized and conjugated to pluronic-silica (PluS) nanoparticles (NPs) where the fluorescence and singlet oxygen generating behavior of the porphyrins were investigated. The highest singlet oxygen quantum yield (ΦΔ) was obtained for ZnP. When the porphyrins were conjugated to the PluS NPs, the ΦΔ was quenched and fluorescence was enhanced. The pore size of the NPs upon conjugation decreased from 18.9 nm for PluS NPs to 2.4 nm (for ZnP as an example) as determined by applying the Brunauer–Emmett–Teller method. The porphyrin complexes and their conjugates were tested for their photodynamic therapy (PDT) activity on MCF-7 breast cancer cells. It was found that ZnP and its conjugate showed the highest PDT activity. The p > 0.05 indicated that ZnP is significantly different than GaP and SiP.
- Full Text:
- Date Issued: 2016
- Authors: Managa, Muthumuni , Britton, Jonathan , Prinsloo, Earl , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/239698 , vital:50756 , xlink:href="https://doi.org/10.1080/00958972.2016.1236372"
- Description: 5, 10, 15, Triphenyl-20-p-phenoxy benzoic acid porphyrins (P) containing Zn (ZnP), Ga (GaP), and Si (SiP) were synthesized and conjugated to pluronic-silica (PluS) nanoparticles (NPs) where the fluorescence and singlet oxygen generating behavior of the porphyrins were investigated. The highest singlet oxygen quantum yield (ΦΔ) was obtained for ZnP. When the porphyrins were conjugated to the PluS NPs, the ΦΔ was quenched and fluorescence was enhanced. The pore size of the NPs upon conjugation decreased from 18.9 nm for PluS NPs to 2.4 nm (for ZnP as an example) as determined by applying the Brunauer–Emmett–Teller method. The porphyrin complexes and their conjugates were tested for their photodynamic therapy (PDT) activity on MCF-7 breast cancer cells. It was found that ZnP and its conjugate showed the highest PDT activity. The p > 0.05 indicated that ZnP is significantly different than GaP and SiP.
- Full Text:
- Date Issued: 2016
Effects of Pteronia incana (Blue bush) invasion on grass biomass production, soil chemical characteristics and peoples' livelihoods in Ngqushwa communal rangelands, Eastern Cape
- Authors: Ntutha, T
- Date: 2016
- Subjects: Invasive plants -- South Africa -- Eastern Cape Shrublands -- South Africa -- Eastern Cape Rangelands -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/4682 , vital:28493
- Description: The objective of the study was to assess the farmers’ knowledge and perceptions of P. incana invasion and impacts on rangeland, livestock production and livelihood in four communal grazing areas. Twenty households per village that own livestock were randomly selected to conduct an interview using an open and closed ended questionnaire. In each household, an old and knowledgeable respondent about P. incana invasion was used as a selection criterion. For scientific assessment of range condition, the experiment was conducted in a 270 m x 100 m trial plots that were established in 2014. The area was divided into 3 open and 3 fenced subplots each having an area of 45 m x 100 m established laid down a slope gradient. Each plot was divided into four equal subplots to apply the control treatments. Therefore, the trial layout was a stratified block experiment of four treatments replicated three times. The four control treatments applied to P. incana invasion were chopping and resting (CR), resting without chopping (RWOC), grazing and chopping (GC), grazing without chopping (GWOC). A step point method was applied in each transect to monitor species composition and P. incana cover. On the fenced plots two exclosures of 1mx1m size were randomly distributed to make sure that resting is maintained. Within exclosures 0.25 m2quadrates in each were put randomly to measure biomass. Density of P. incana was determined from 5 m x 5 m quadrates that were placed randomly within each sub-plot. The density and height of individual shrub plant was measured. All rooted live woody plants were recorded and counted in each quadrate. The results revealed that species composition was not affected (P>0.05) by the treatments applied. The herbage height and basal cover had greater values (P<0.05) under rested plus chopping (CR) treatment followed by grazed plus chopping (GC). Grass biomass production and essential nutrients showed a greater concentration (P<0.05) under CR treatment than any treatments applied. The results on perceptions revealed that goats had the highest mean household holding number than any other livestock species across the selected villages in all the villages. Respondents indicated that both goats and cattle had equal or more importance than sheep. Three out of four villages raised cattle primarily for income generation and secondarily for cultural purposes like slaughtering during weddings ceremonies, amazila and also during woman circumcisions (Ntonjane). Similarly, goats and sheep were primarily raised for cash income generation. The results revealed that livestock population decreased over ten to twenty years (one-two decades) and poor rangeland condition is assumed to be the cause of the situation as feed is the key factor for production. The area was dominated by the grasses rather than by browse woody species so the above results are possible as the P. incana is more competitive than grasses. It was concluded that P. incana is detrimental to both rangeland and animal production. Forage and animal performance as well as farmers’ economic status (livelihoods) were negatively affected by P. incana invasion and the scientific assessment reported it to be detrimental to agriculture. Thus chopping and resting (CR) treatment resulted in a greater improvement of the basal cover, biomass production, soil nutrients as well as grass height than the other treatments applied. Therefore it can be concluded that chopping and resting the veld invaded with P. incana can improve the range and consequently animal production.
- Full Text:
- Date Issued: 2016
- Authors: Ntutha, T
- Date: 2016
- Subjects: Invasive plants -- South Africa -- Eastern Cape Shrublands -- South Africa -- Eastern Cape Rangelands -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/4682 , vital:28493
- Description: The objective of the study was to assess the farmers’ knowledge and perceptions of P. incana invasion and impacts on rangeland, livestock production and livelihood in four communal grazing areas. Twenty households per village that own livestock were randomly selected to conduct an interview using an open and closed ended questionnaire. In each household, an old and knowledgeable respondent about P. incana invasion was used as a selection criterion. For scientific assessment of range condition, the experiment was conducted in a 270 m x 100 m trial plots that were established in 2014. The area was divided into 3 open and 3 fenced subplots each having an area of 45 m x 100 m established laid down a slope gradient. Each plot was divided into four equal subplots to apply the control treatments. Therefore, the trial layout was a stratified block experiment of four treatments replicated three times. The four control treatments applied to P. incana invasion were chopping and resting (CR), resting without chopping (RWOC), grazing and chopping (GC), grazing without chopping (GWOC). A step point method was applied in each transect to monitor species composition and P. incana cover. On the fenced plots two exclosures of 1mx1m size were randomly distributed to make sure that resting is maintained. Within exclosures 0.25 m2quadrates in each were put randomly to measure biomass. Density of P. incana was determined from 5 m x 5 m quadrates that were placed randomly within each sub-plot. The density and height of individual shrub plant was measured. All rooted live woody plants were recorded and counted in each quadrate. The results revealed that species composition was not affected (P>0.05) by the treatments applied. The herbage height and basal cover had greater values (P<0.05) under rested plus chopping (CR) treatment followed by grazed plus chopping (GC). Grass biomass production and essential nutrients showed a greater concentration (P<0.05) under CR treatment than any treatments applied. The results on perceptions revealed that goats had the highest mean household holding number than any other livestock species across the selected villages in all the villages. Respondents indicated that both goats and cattle had equal or more importance than sheep. Three out of four villages raised cattle primarily for income generation and secondarily for cultural purposes like slaughtering during weddings ceremonies, amazila and also during woman circumcisions (Ntonjane). Similarly, goats and sheep were primarily raised for cash income generation. The results revealed that livestock population decreased over ten to twenty years (one-two decades) and poor rangeland condition is assumed to be the cause of the situation as feed is the key factor for production. The area was dominated by the grasses rather than by browse woody species so the above results are possible as the P. incana is more competitive than grasses. It was concluded that P. incana is detrimental to both rangeland and animal production. Forage and animal performance as well as farmers’ economic status (livelihoods) were negatively affected by P. incana invasion and the scientific assessment reported it to be detrimental to agriculture. Thus chopping and resting (CR) treatment resulted in a greater improvement of the basal cover, biomass production, soil nutrients as well as grass height than the other treatments applied. Therefore it can be concluded that chopping and resting the veld invaded with P. incana can improve the range and consequently animal production.
- Full Text:
- Date Issued: 2016
Effects of substrate on essential fatty acids produced by phytobenthos in an austral temperate river system
- Dalu, Tatenda, Galloway, Aaron W E, Richoux, Nicole B, Froneman, P William
- Authors: Dalu, Tatenda , Galloway, Aaron W E , Richoux, Nicole B , Froneman, P William
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68002 , vital:29179 , https://doi.org/10.1086/688698
- Description: Publisher version , Aquatic and riparian habitats increasingly are affected by anthropogenic stressors, but the effects of these stressors on the nutritional quality of primary producers are often unknown. We compared essential fatty acids (EFAs) in the phytobenthos (benthic algae) growing on different substrate types (bricks, clay tiles, rocks, macrophytes, and sediments) at 2 river sites subject to differing anthropogenic stressors (using nutrient concentration as a proxy) in a temperate southern hemisphere location. We hypothesized that the fatty acid (FA) content of phytobenthos changes in response to shifts in local nutrient availability but not substrate type. EFA content (18∶2ω6, 18∶3ω3, 20∶4ω6, 20∶5ω3, and 22∶6ω3) in the phytobenthos differed overall among substrates, sites, and seasons and was generally greater in summer than in autumn and winter. EFA content was significantly greater on artificial than natural substrates and was greater at the nutrient-enriched downstream site than at the upstream site. The response of EFA content at the downstream site suggests that land use affected the synthesis of EFAs by phytobenthos and, hence, food quality for aquatic consumers. These findings indicate a potential link between physical factors, such as substrate availability and land management, and the quality of basal food resources available to primary consumers in aquatic food webs.
- Full Text: false
- Date Issued: 2016
- Authors: Dalu, Tatenda , Galloway, Aaron W E , Richoux, Nicole B , Froneman, P William
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68002 , vital:29179 , https://doi.org/10.1086/688698
- Description: Publisher version , Aquatic and riparian habitats increasingly are affected by anthropogenic stressors, but the effects of these stressors on the nutritional quality of primary producers are often unknown. We compared essential fatty acids (EFAs) in the phytobenthos (benthic algae) growing on different substrate types (bricks, clay tiles, rocks, macrophytes, and sediments) at 2 river sites subject to differing anthropogenic stressors (using nutrient concentration as a proxy) in a temperate southern hemisphere location. We hypothesized that the fatty acid (FA) content of phytobenthos changes in response to shifts in local nutrient availability but not substrate type. EFA content (18∶2ω6, 18∶3ω3, 20∶4ω6, 20∶5ω3, and 22∶6ω3) in the phytobenthos differed overall among substrates, sites, and seasons and was generally greater in summer than in autumn and winter. EFA content was significantly greater on artificial than natural substrates and was greater at the nutrient-enriched downstream site than at the upstream site. The response of EFA content at the downstream site suggests that land use affected the synthesis of EFAs by phytobenthos and, hence, food quality for aquatic consumers. These findings indicate a potential link between physical factors, such as substrate availability and land management, and the quality of basal food resources available to primary consumers in aquatic food webs.
- Full Text: false
- Date Issued: 2016
Effects of the biocontrol agent, coelocephalapion camarae kissinger, galling on petiole tissues, plant growth and stored reserves in plant parts of two lantana camara L.(verbenaceae) varieties
- Authors: Kistensamy, Yoganambal
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3126 , vital:20372
- Description: The agent evaluated in this study, Coelocephalapion camarae Kissinger (Brentidae), a petiole galling apionid, was released against Lantana camara L. (Verbenaceae) in South Africa and has the potential to significantly contribute to the control of this noxious weed. An important aspect of evaluating the effectiveness of a biocontrol agent; include the understanding of the mechanism in which the biocontrol agent causes damage to the plant and the plant’s response to this damage. Another aspect that was considered in evaluating the effects of the apionid was the varietal differences that exist within the weedy L. camara complex. Larval feeding of C. camarae damaged the tissue in the petioles causing gall formation and this was quantified on two common South African L. camara varieties (017 and 018). Up to 100% of the vascular tissue (xylem and phloem) of effected petioles was eaten by larvae, 25 days after ovipostion in both the L. camara varieties, effectively severing the vascular connection from the leaves. The effect of feeding and galling by different population densities of C. camarae, on biomass and total soluble sugar and starch concentrations of different plant parts was measured on these two varieties during autumn, and compared to a similar study, done during summer. Relatively low galling percentages were achieved in the experiments of this study. Plant growth was less affected by apionid feeding at similar galling levels, as higher galling densities in these trials were similar to those at low exposures in trials by Baars (2002). The dry weights of all individual and combined plant parts for lantana variety 017 was less for both adult density exposures after 70 days compared to the weights of its controls, although not statistically significant at P>0.05 The opposite effect, though barely noticeable was recorded for lantana variety 018; here, the dry weights of individual plant parts and as whole plants weighed more in the plants exposed to both densities of weevil feeding and galling after 70 days, compared to its controls. Coelocephalapion camarae herbivory may thus be more effective in inflicting damage on some L. camara varieties compared to others. The effects of late season carbohydrate storage revealed that, from early- to mid-autumn starch concentrations increased significantly in stems of both L. camara varieties and L. camara var. 018 had larger starch reserves for winter. In L. camara var. 018 stems, starch increased 52 times and concentrations doubled in stems of L. camara var 017. The increase in the sugar and decrease in starch concentrations in leaves of plants of both varieties exposed to apionids in this study was attributed to a possible reduction of available nitrogen and phosphorus, due to apionid feeding, whilst starch was reallocated within the plants to stems and roots. The increase in starch concentrations in stems of plants that were exposed to apionids may have been expected, as compensation for herbivory has been associated with, increases in photosynthetic rates and the mobilization of stored resources. Herbivory by the apionid early in the growing season may be easily compensated for by L. camara as there are nutrient flushes experienced by plants that allows the maximum uptake of nutrients facilitating recovery, whereas later in the season plants suffer lower nutrient availability and don’t recover so readily. Both early and late in the season the accumulated effects of C. camarae feeding over time will undoubtedly decrease fitness of most lantana varieties.
- Full Text:
- Date Issued: 2016
- Authors: Kistensamy, Yoganambal
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3126 , vital:20372
- Description: The agent evaluated in this study, Coelocephalapion camarae Kissinger (Brentidae), a petiole galling apionid, was released against Lantana camara L. (Verbenaceae) in South Africa and has the potential to significantly contribute to the control of this noxious weed. An important aspect of evaluating the effectiveness of a biocontrol agent; include the understanding of the mechanism in which the biocontrol agent causes damage to the plant and the plant’s response to this damage. Another aspect that was considered in evaluating the effects of the apionid was the varietal differences that exist within the weedy L. camara complex. Larval feeding of C. camarae damaged the tissue in the petioles causing gall formation and this was quantified on two common South African L. camara varieties (017 and 018). Up to 100% of the vascular tissue (xylem and phloem) of effected petioles was eaten by larvae, 25 days after ovipostion in both the L. camara varieties, effectively severing the vascular connection from the leaves. The effect of feeding and galling by different population densities of C. camarae, on biomass and total soluble sugar and starch concentrations of different plant parts was measured on these two varieties during autumn, and compared to a similar study, done during summer. Relatively low galling percentages were achieved in the experiments of this study. Plant growth was less affected by apionid feeding at similar galling levels, as higher galling densities in these trials were similar to those at low exposures in trials by Baars (2002). The dry weights of all individual and combined plant parts for lantana variety 017 was less for both adult density exposures after 70 days compared to the weights of its controls, although not statistically significant at P>0.05 The opposite effect, though barely noticeable was recorded for lantana variety 018; here, the dry weights of individual plant parts and as whole plants weighed more in the plants exposed to both densities of weevil feeding and galling after 70 days, compared to its controls. Coelocephalapion camarae herbivory may thus be more effective in inflicting damage on some L. camara varieties compared to others. The effects of late season carbohydrate storage revealed that, from early- to mid-autumn starch concentrations increased significantly in stems of both L. camara varieties and L. camara var. 018 had larger starch reserves for winter. In L. camara var. 018 stems, starch increased 52 times and concentrations doubled in stems of L. camara var 017. The increase in the sugar and decrease in starch concentrations in leaves of plants of both varieties exposed to apionids in this study was attributed to a possible reduction of available nitrogen and phosphorus, due to apionid feeding, whilst starch was reallocated within the plants to stems and roots. The increase in starch concentrations in stems of plants that were exposed to apionids may have been expected, as compensation for herbivory has been associated with, increases in photosynthetic rates and the mobilization of stored resources. Herbivory by the apionid early in the growing season may be easily compensated for by L. camara as there are nutrient flushes experienced by plants that allows the maximum uptake of nutrients facilitating recovery, whereas later in the season plants suffer lower nutrient availability and don’t recover so readily. Both early and late in the season the accumulated effects of C. camarae feeding over time will undoubtedly decrease fitness of most lantana varieties.
- Full Text:
- Date Issued: 2016
Effects of the invasive shrub, Lantana camara, on soil properties in the Eastern Cape, South Africa
- Ruwanza, Sheunesu, Shackleton, Charlie M
- Authors: Ruwanza, Sheunesu , Shackleton, Charlie M
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180459 , vital:43391 , xlink:href="https://doi.org/10.1111/wbm.12094"
- Description: Lantana camara L. is an invasive alien shrub of worldwide significance due to its impacts on biodiversity. It can alter the soil properties of invaded ecosystems and, as a result, affect management outcomes. However, knowledge on the impacts of L. camara on soil properties is scanty, especially in South Africa, despite the pervasive presence of the plant in the country. In this comparative study, the soils underneath L. camara were assessed in order to determine if they had different properties (soil physico-chemical properties, penetration resistance, infiltration, hydraulic conductivity and water repellency) in comparison to the soils in adjacent natural sites in the Eastern Cape, South Africa. Soil samples were collected from the top soil beneath the canopy of both L. camara-invaded and adjacent natural sites in five different locations over three summer months. The soils that were collected from underneath L. camara had a significantly higher total C, total P, gravimetric soil moisture (in November and December) and were repellent, compared to the soils in the adjacent natural sites. Soil penetration resistance was significantly higher in the natural sites than in the L. camara-invaded sites. The soil hydraulic conductivity, soil infiltration rate, soil pH, exchangeable cations and total N showed no significant difference between the invaded and the natural sites. It appears that the soils underneath L. camara have a high total C and total P, soil moisture and are repellent, thus influencing nutrient cycling, potentially making the soil properties underneath it ideal for its own growth. This could contribute to the success of L. camara as an invasive species.
- Full Text:
- Date Issued: 2016
- Authors: Ruwanza, Sheunesu , Shackleton, Charlie M
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180459 , vital:43391 , xlink:href="https://doi.org/10.1111/wbm.12094"
- Description: Lantana camara L. is an invasive alien shrub of worldwide significance due to its impacts on biodiversity. It can alter the soil properties of invaded ecosystems and, as a result, affect management outcomes. However, knowledge on the impacts of L. camara on soil properties is scanty, especially in South Africa, despite the pervasive presence of the plant in the country. In this comparative study, the soils underneath L. camara were assessed in order to determine if they had different properties (soil physico-chemical properties, penetration resistance, infiltration, hydraulic conductivity and water repellency) in comparison to the soils in adjacent natural sites in the Eastern Cape, South Africa. Soil samples were collected from the top soil beneath the canopy of both L. camara-invaded and adjacent natural sites in five different locations over three summer months. The soils that were collected from underneath L. camara had a significantly higher total C, total P, gravimetric soil moisture (in November and December) and were repellent, compared to the soils in the adjacent natural sites. Soil penetration resistance was significantly higher in the natural sites than in the L. camara-invaded sites. The soil hydraulic conductivity, soil infiltration rate, soil pH, exchangeable cations and total N showed no significant difference between the invaded and the natural sites. It appears that the soils underneath L. camara have a high total C and total P, soil moisture and are repellent, thus influencing nutrient cycling, potentially making the soil properties underneath it ideal for its own growth. This could contribute to the success of L. camara as an invasive species.
- Full Text:
- Date Issued: 2016
Efficiency analysis of electricity distribution by South African Municipalities: a cost frontier approach
- Gqwaka, Aviwe Phelele Sebatian
- Authors: Gqwaka, Aviwe Phelele Sebatian
- Date: 2016
- Subjects: Electric power distribution -- South Africa Public utilities -- South Africa Local government -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/10299 , vital:26650
- Description: Efficiency analysis in the public sector assesses the performance of municipal and government entities in their provision of services to the public. South Africa, in particular, has experienced a large degree of negative feedback with respect to the ability of the government and its municipal departments to provide basic services to citizens. This has led to a number of service delivery protests throughout the country. To remedy this, the ability of the municipality to provide basic services needs to be assessed in order for improvements to be made. A first step in this process would be to determine the efficiency with which municipalities are providing these services. This study focuses on a particular municipal service, namely electricity distribution. Primarily, the efficiency with which municipalities provide electricity to consumers is determined. This is achieved using the parametric cost frontier approach, which is appropriate since municipalities aim to reduce the costs incurred in distributing electricity. The municipalities are compared to a frontier (theoretical best practice) from which inferences on their performances can be made. Those municipalities whose performances are not optimal, deviate from the frontier. The deviations (errors) are then assumed to be caused by two factors, namely stochastic random noise and inefficiency. This composition accounts for effects for which municipalities cannot control (stochastic random noise) and those for which it can (inefficiency). The parametric nature of the cost frontier approach allows for distributional assumptions to be made on these factors. Stochastic random noise is always assumed to be normally distributed, while inefficiency is assumed to be one-sided and positively skewed.
- Full Text:
- Date Issued: 2016
- Authors: Gqwaka, Aviwe Phelele Sebatian
- Date: 2016
- Subjects: Electric power distribution -- South Africa Public utilities -- South Africa Local government -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/10299 , vital:26650
- Description: Efficiency analysis in the public sector assesses the performance of municipal and government entities in their provision of services to the public. South Africa, in particular, has experienced a large degree of negative feedback with respect to the ability of the government and its municipal departments to provide basic services to citizens. This has led to a number of service delivery protests throughout the country. To remedy this, the ability of the municipality to provide basic services needs to be assessed in order for improvements to be made. A first step in this process would be to determine the efficiency with which municipalities are providing these services. This study focuses on a particular municipal service, namely electricity distribution. Primarily, the efficiency with which municipalities provide electricity to consumers is determined. This is achieved using the parametric cost frontier approach, which is appropriate since municipalities aim to reduce the costs incurred in distributing electricity. The municipalities are compared to a frontier (theoretical best practice) from which inferences on their performances can be made. Those municipalities whose performances are not optimal, deviate from the frontier. The deviations (errors) are then assumed to be caused by two factors, namely stochastic random noise and inefficiency. This composition accounts for effects for which municipalities cannot control (stochastic random noise) and those for which it can (inefficiency). The parametric nature of the cost frontier approach allows for distributional assumptions to be made on these factors. Stochastic random noise is always assumed to be normally distributed, while inefficiency is assumed to be one-sided and positively skewed.
- Full Text:
- Date Issued: 2016
Efficient energy transfer in ethynyl bridged corrole–BODIPY dyads
- Yan, Yu, Wu, Fan, Qin, Jiawei, Xu, Haijun, Shi, Maohu, Zhou, Jingfeng, Mack, John, Fomo, Gertrude, Nyokong, Tebello, Shen, Zhen
- Authors: Yan, Yu , Wu, Fan , Qin, Jiawei , Xu, Haijun , Shi, Maohu , Zhou, Jingfeng , Mack, John , Fomo, Gertrude , Nyokong, Tebello , Shen, Zhen
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240899 , vital:50883 , xlink:href="https://doi.org/10.1039/C6RA12271J"
- Description: A series of new corrole–BODIPY dyads bridged by ethynyl linker moieties have been synthesized in high yields and fully characterized. The direction of energy transfer upon electronic excitation has been explored, and was found to be dependent on the number of corrole rings and their connection position on the BODIPY core. Intense bands in the absorption spectrum cover most of the visible region, which is potentially advantageous for capturing solar energy. Studies on the excitation spectra and lifetimes suggest that the energy transfer efficiency between the BODIPY and corrole moieties reaches almost 85%, which appears to be efficient in the context of energy transfer within the singlet manifold.
- Full Text:
- Date Issued: 2016
- Authors: Yan, Yu , Wu, Fan , Qin, Jiawei , Xu, Haijun , Shi, Maohu , Zhou, Jingfeng , Mack, John , Fomo, Gertrude , Nyokong, Tebello , Shen, Zhen
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240899 , vital:50883 , xlink:href="https://doi.org/10.1039/C6RA12271J"
- Description: A series of new corrole–BODIPY dyads bridged by ethynyl linker moieties have been synthesized in high yields and fully characterized. The direction of energy transfer upon electronic excitation has been explored, and was found to be dependent on the number of corrole rings and their connection position on the BODIPY core. Intense bands in the absorption spectrum cover most of the visible region, which is potentially advantageous for capturing solar energy. Studies on the excitation spectra and lifetimes suggest that the energy transfer efficiency between the BODIPY and corrole moieties reaches almost 85%, which appears to be efficient in the context of energy transfer within the singlet manifold.
- Full Text:
- Date Issued: 2016
Elder man mixing traditional beer
- Family members, McConnachie, Boudina
- Authors: Family members , McConnachie, Boudina
- Date: 2016
- Subjects: Keiskammahoek (South Africa)
- Type: Image
- Identifier: http://hdl.handle.net/10962/219808 , vital:48559 , KHP-189
- Description: Photograph of Elder man crouching in front of group of family members and Dr McConnachie to mix traditional beer in a tin. , Use of this resource is governed by the terms and conditions of the Creative Commons "Attribution-NonCommercial-ShareAlike" License (http://creativecommons.org/licenses/by-nc-sa/2.0/)
- Full Text: false
- Date Issued: 2016
- Authors: Family members , McConnachie, Boudina
- Date: 2016
- Subjects: Keiskammahoek (South Africa)
- Type: Image
- Identifier: http://hdl.handle.net/10962/219808 , vital:48559 , KHP-189
- Description: Photograph of Elder man crouching in front of group of family members and Dr McConnachie to mix traditional beer in a tin. , Use of this resource is governed by the terms and conditions of the Creative Commons "Attribution-NonCommercial-ShareAlike" License (http://creativecommons.org/licenses/by-nc-sa/2.0/)
- Full Text: false
- Date Issued: 2016
Electrical power output estimation model for a conical diffuser augmented wind turbine
- Authors: Masukume, Peace-Maker
- Date: 2016
- Subjects: Wind power , Wind turbines , Renewable energy sources
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/1517 , vital:27404
- Description: Energy is integral to the quality of life of any society. However, meeting the demand for energy sustainably is the main challenge facing humanity. In general, non-renewable energy resources are used to supply the ever increasing energy demand. However, the extraction and processing of these resources is accompanied by the production of wastes which are a health hazard and impact negatively on climate change. Considering the finite nature of non-renewable sources, the environmental concerns which are associated with their usage and ensuring energy security, renewable energy sources have been brought in the energy supply chain. Wind energy is one of the renewable energy sources which has been supplying electrical energy to the ever increasing energy demand of humanity. Wind energy technology is a mature technology which over and above the bare (conventional) wind turbine technology has seen the development of duct augmented wind turbines. Ducts are used to encase wind turbine rotors to augment the power output of wind turbines especially in low wind speed areas. Though the technology has been under study for decades now, research indicates that there is no known model to estimate the power output of a diffuser augmented wind turbine. This thesis presents the development of the conical Diffuser Augmented Wind Turbine (DAWT) power output estimation model and its validation.
- Full Text:
- Date Issued: 2016
- Authors: Masukume, Peace-Maker
- Date: 2016
- Subjects: Wind power , Wind turbines , Renewable energy sources
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/1517 , vital:27404
- Description: Energy is integral to the quality of life of any society. However, meeting the demand for energy sustainably is the main challenge facing humanity. In general, non-renewable energy resources are used to supply the ever increasing energy demand. However, the extraction and processing of these resources is accompanied by the production of wastes which are a health hazard and impact negatively on climate change. Considering the finite nature of non-renewable sources, the environmental concerns which are associated with their usage and ensuring energy security, renewable energy sources have been brought in the energy supply chain. Wind energy is one of the renewable energy sources which has been supplying electrical energy to the ever increasing energy demand of humanity. Wind energy technology is a mature technology which over and above the bare (conventional) wind turbine technology has seen the development of duct augmented wind turbines. Ducts are used to encase wind turbine rotors to augment the power output of wind turbines especially in low wind speed areas. Though the technology has been under study for decades now, research indicates that there is no known model to estimate the power output of a diffuser augmented wind turbine. This thesis presents the development of the conical Diffuser Augmented Wind Turbine (DAWT) power output estimation model and its validation.
- Full Text:
- Date Issued: 2016
Electrocatalytic activity of nanocomposites of sulphur doped graphene oxide and nanosized cobalt phthalocyanines
- Shumba, Munyaradzi, Nyokong, Tebello
- Authors: Shumba, Munyaradzi , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188530 , vital:44762 , xlink:href="https://doi.org/10.1002/elan.201600226"
- Description: In this work we explore the electrocatalytic activity of nanocomposites of reduced sulphur doped graphene oxide nanosheets (rSDGONS) and cobalt phthalocyanine (CoPc) or cobalt tetra amino phthalocyanine (CoTAPc) towards hydrogen peroxide. Transmission electron microscopy, scanning electron microscopy, X-ray photon spectroscopy, X-ray diffraction, chronoamperometry, linear scan voltammetry and cyclic voltammetry were used to characterize the nanocomposites. Nanosized CoPc showed superior (in terms of currents) electrocatalytic oxidation and reduction of hydrogen peroxide compared to CoTAPc nanoparticles (CoTAPcNP). The lowest detection limit was obtained for hydrogen peroxide oxidation on electrodes modified with CoPcNP-rSDGONS at 1.49 µM. The same electrode gave a high adsorption equilibrium constant of 1.27×103 mol−1 and a Gibbs free energy of −17.71 kJ/mol, indicative of a spontaneous reaction on the electrode surface.
- Full Text:
- Date Issued: 2016
- Authors: Shumba, Munyaradzi , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188530 , vital:44762 , xlink:href="https://doi.org/10.1002/elan.201600226"
- Description: In this work we explore the electrocatalytic activity of nanocomposites of reduced sulphur doped graphene oxide nanosheets (rSDGONS) and cobalt phthalocyanine (CoPc) or cobalt tetra amino phthalocyanine (CoTAPc) towards hydrogen peroxide. Transmission electron microscopy, scanning electron microscopy, X-ray photon spectroscopy, X-ray diffraction, chronoamperometry, linear scan voltammetry and cyclic voltammetry were used to characterize the nanocomposites. Nanosized CoPc showed superior (in terms of currents) electrocatalytic oxidation and reduction of hydrogen peroxide compared to CoTAPc nanoparticles (CoTAPcNP). The lowest detection limit was obtained for hydrogen peroxide oxidation on electrodes modified with CoPcNP-rSDGONS at 1.49 µM. The same electrode gave a high adsorption equilibrium constant of 1.27×103 mol−1 and a Gibbs free energy of −17.71 kJ/mol, indicative of a spontaneous reaction on the electrode surface.
- Full Text:
- Date Issued: 2016