A mobile based control system for smart homes
- Authors: Tshimanga, Danny Kazadi
- Date: 2022-03
- Subjects: Smart power grids , Home automation
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22632 , vital:52606
- Description: A Smart Home Control System can provide a secure home, convenience, comfort, and interactivity of life in a particular home. The system can enable the automatic controlling of a house via a Smart Phone. These systems are becoming vital and widely used in homes to improve conditions of life. Most commercial home automation systems are expensive and their maintenance would require experts who understand the underlying implementation of the systems. This study developed a mobile-based home automation system prototype. The system was developed using the waterfall model methodology. To evaluate the developed system, the study used a simulation method. Ten trials were conducted to determine the performance of the implemented system. The mean time to failure was used to evaluate the system’ reliability. The system’s performance analysis revealed that the developed system performed better than the two other approaches; the Bluetooth and ZigBee. The developed system showed a 0 percent error, while the Bluetooth had 8 percent error and ZigBee 6 percent error. The reliability results showed the average lifespan of assets in the system before they could fail. Knowing the lifespan of an asset before it fails can help in reducing downtime of the system by planning or scheduling maintenance and develop an improved maintenance strategy. , Thesis (MSc) -- Faculty of Science and Agriculture, 2021
- Full Text:
- Authors: Tshimanga, Danny Kazadi
- Date: 2022-03
- Subjects: Smart power grids , Home automation
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22632 , vital:52606
- Description: A Smart Home Control System can provide a secure home, convenience, comfort, and interactivity of life in a particular home. The system can enable the automatic controlling of a house via a Smart Phone. These systems are becoming vital and widely used in homes to improve conditions of life. Most commercial home automation systems are expensive and their maintenance would require experts who understand the underlying implementation of the systems. This study developed a mobile-based home automation system prototype. The system was developed using the waterfall model methodology. To evaluate the developed system, the study used a simulation method. Ten trials were conducted to determine the performance of the implemented system. The mean time to failure was used to evaluate the system’ reliability. The system’s performance analysis revealed that the developed system performed better than the two other approaches; the Bluetooth and ZigBee. The developed system showed a 0 percent error, while the Bluetooth had 8 percent error and ZigBee 6 percent error. The reliability results showed the average lifespan of assets in the system before they could fail. Knowing the lifespan of an asset before it fails can help in reducing downtime of the system by planning or scheduling maintenance and develop an improved maintenance strategy. , Thesis (MSc) -- Faculty of Science and Agriculture, 2021
- Full Text:
Assessment of soil erosion based on clustered geoinformatics approaches: a case study of Tyume River Catchment, Eastern Cape, South Africa
- Mbatyoti, Siyanda https://orcid.org/0000-0002-9736-5684
- Authors: Mbatyoti, Siyanda https://orcid.org/0000-0002-9736-5684
- Date: 2022-03
- Subjects: Soil erosion , Geoinformatics
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22852 , vital:52969
- Description: This research centres on the holistic assessments of spatial and temporal dimensions of soil erosion zones based on the parameters of geomorphometry, hydro-statistics, and land use/cover dynamics. The study used a case study approach based on a clustered framework model of soil erosion parameters in the Tyume River basin in Eastern Cape, South Africa. The methods adopted for the investigation are, namely; non-parametric time-series assessment of streamflow dataset, semidecadal assessment of land use/cover (LU/C) dynamics, geospatial analysis of geomorphometric variables, vulnerability analysis of soil erosion zones, regression analysis of determination coefficient, and Receiver Operating Characteristic Curve (ROC). The delineation of soil erosion zones was based on the integrated analysis of the parameters of geomorphometry, geology, hydrology, and land use/ cover. The result of the hydro-statistical analysis of the Tyume River reports a major decline in the inter-annual regime frequency of storm flow based on the Mann- Kendall (MK) test and Sen’s slope assessment in 1992 (p-value = 0.031), 1997 (p-value = 0.045), 2003 (p-value = 0.021), 2008 (p-value = 0.003), and 2016 (p-value = 0.002). The MK test depicted a recurrence of peak streamflow acceleration in every three years based on low-flow and highflow transition. The sensitivity of LU/C to temporal dynamics of streamflow trends shown by the coefficient of correlation of trends of the LU/C water bodies with streamflow semi-decadal acceleration indicates a moderately relevant relationship, R = 0.76. The temporal analysis of LU/C and hydro-statistical analysis shows that the Tyume basin was highly vulnerable to soil erosion by water in 1999, 2009, and 2019. The vulnerability of the Tyume River basin in 2019 is exceptional and this is due to the conversion of forested area (woodland) into a built-up environment and farmland, with a high vulnerability in 2019 due to the slump in the rate of change of woodland and precipitation, and the increase in the rate of built-up and agricultural activities. The soil erosion vulnerability mapping divides the river basin into the critical high, high, moderate, low, nonvulnerable zones that cover 40 km2, 135 km2, 209 km2, and 186 km2 respectively. Regression analysis shows that the areas of soil erosion in the Tyume basin are moderately represented by the model (R2 = 56) while the model performance assessment based on success rate and prediction rate estimation from the area under the ROC curve shows that the model is good, Area Under Curve of the ROC = 0.899, and 0.897. The analysis suggests that soil erosion is driven by the impact of land use/land cover change, particularly in areas of high drainage density. Significantly, high vegetation density played a vital role in lowering high-flow on the hill-slope and low topographic wetness area as well as in areas with erodible geologic properties. The study, therefore, recommends the advocacy of crop rotation method of agricultural practice in the highly critical areas of soil erosion and recommends the development of riparian forests around the Tyume River. The study provides important information for environmental stakeholders on degradable areas which may require the urgent implementation of sustainable development measures. , Thesis (MPhil) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Authors: Mbatyoti, Siyanda https://orcid.org/0000-0002-9736-5684
- Date: 2022-03
- Subjects: Soil erosion , Geoinformatics
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22852 , vital:52969
- Description: This research centres on the holistic assessments of spatial and temporal dimensions of soil erosion zones based on the parameters of geomorphometry, hydro-statistics, and land use/cover dynamics. The study used a case study approach based on a clustered framework model of soil erosion parameters in the Tyume River basin in Eastern Cape, South Africa. The methods adopted for the investigation are, namely; non-parametric time-series assessment of streamflow dataset, semidecadal assessment of land use/cover (LU/C) dynamics, geospatial analysis of geomorphometric variables, vulnerability analysis of soil erosion zones, regression analysis of determination coefficient, and Receiver Operating Characteristic Curve (ROC). The delineation of soil erosion zones was based on the integrated analysis of the parameters of geomorphometry, geology, hydrology, and land use/ cover. The result of the hydro-statistical analysis of the Tyume River reports a major decline in the inter-annual regime frequency of storm flow based on the Mann- Kendall (MK) test and Sen’s slope assessment in 1992 (p-value = 0.031), 1997 (p-value = 0.045), 2003 (p-value = 0.021), 2008 (p-value = 0.003), and 2016 (p-value = 0.002). The MK test depicted a recurrence of peak streamflow acceleration in every three years based on low-flow and highflow transition. The sensitivity of LU/C to temporal dynamics of streamflow trends shown by the coefficient of correlation of trends of the LU/C water bodies with streamflow semi-decadal acceleration indicates a moderately relevant relationship, R = 0.76. The temporal analysis of LU/C and hydro-statistical analysis shows that the Tyume basin was highly vulnerable to soil erosion by water in 1999, 2009, and 2019. The vulnerability of the Tyume River basin in 2019 is exceptional and this is due to the conversion of forested area (woodland) into a built-up environment and farmland, with a high vulnerability in 2019 due to the slump in the rate of change of woodland and precipitation, and the increase in the rate of built-up and agricultural activities. The soil erosion vulnerability mapping divides the river basin into the critical high, high, moderate, low, nonvulnerable zones that cover 40 km2, 135 km2, 209 km2, and 186 km2 respectively. Regression analysis shows that the areas of soil erosion in the Tyume basin are moderately represented by the model (R2 = 56) while the model performance assessment based on success rate and prediction rate estimation from the area under the ROC curve shows that the model is good, Area Under Curve of the ROC = 0.899, and 0.897. The analysis suggests that soil erosion is driven by the impact of land use/land cover change, particularly in areas of high drainage density. Significantly, high vegetation density played a vital role in lowering high-flow on the hill-slope and low topographic wetness area as well as in areas with erodible geologic properties. The study, therefore, recommends the advocacy of crop rotation method of agricultural practice in the highly critical areas of soil erosion and recommends the development of riparian forests around the Tyume River. The study provides important information for environmental stakeholders on degradable areas which may require the urgent implementation of sustainable development measures. , Thesis (MPhil) -- Faculty of Science and Agriculture, 2022
- Full Text:
Effects of climatic variability on maize productivity in South Africa from 1937-2018
- Awum Awum, Rudin https://orcid.org/ 0000-0002-8740-6163
- Authors: Awum Awum, Rudin https://orcid.org/ 0000-0002-8740-6163
- Date: 2022-03
- Subjects: Crops and climate , Climatic changes
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/21410 , vital:48576
- Description: Climate is an important factor in agricultural production. The world is facing climate change and variability, which result in high temperatures, low rainfall patterns, shortage of water and persistent droughts. Climate change poses a significant threat to South Africa’s water resources, food security, health, infrastructure, ecosystem services and biodiversity. Negative impacts of climate variability on agriculture, especially on maize the staple crop, will worsen the food security status of the nation as most of South Africa’s maize crop is produced in summer and highly depends on rainfall. This study attempted to assess the impact of climate on maize production in South Africa using secondary time series data for the period 1937 to 2018. Rainfall and temperature were used as proxies for climate variability. The Granger Causality Model was used to examine the causal linkages between climatic variables (temperature or rainfall) and maize output in South Africa for the study period. The major outcome of the analysis was that there is a two-way causal relationship between maize production and temperature. The results also indicated that there is uni-directional causality between maize yield and rainfall. Furthermore, the Variance Decomposition Model was used to forecast the relationship between climatic elements and maize production in South Africa. The result showed that all variables have an effect on maize yield, with temperature having the least effect. The last objective of the study was to profile the maize output trend for the period from 1937 to 2018. The main findings from the analysis indicate that maize production in South Africa has a general upward slope. The study recommends that the government should intensify the provision of irrigation systems for the farmers in the most vulnerable areas to mitigate the climate change. Government should also embark on massive campaigns using a variety of media to create the needed public awareness on climate change and its impact on food security. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Authors: Awum Awum, Rudin https://orcid.org/ 0000-0002-8740-6163
- Date: 2022-03
- Subjects: Crops and climate , Climatic changes
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/21410 , vital:48576
- Description: Climate is an important factor in agricultural production. The world is facing climate change and variability, which result in high temperatures, low rainfall patterns, shortage of water and persistent droughts. Climate change poses a significant threat to South Africa’s water resources, food security, health, infrastructure, ecosystem services and biodiversity. Negative impacts of climate variability on agriculture, especially on maize the staple crop, will worsen the food security status of the nation as most of South Africa’s maize crop is produced in summer and highly depends on rainfall. This study attempted to assess the impact of climate on maize production in South Africa using secondary time series data for the period 1937 to 2018. Rainfall and temperature were used as proxies for climate variability. The Granger Causality Model was used to examine the causal linkages between climatic variables (temperature or rainfall) and maize output in South Africa for the study period. The major outcome of the analysis was that there is a two-way causal relationship between maize production and temperature. The results also indicated that there is uni-directional causality between maize yield and rainfall. Furthermore, the Variance Decomposition Model was used to forecast the relationship between climatic elements and maize production in South Africa. The result showed that all variables have an effect on maize yield, with temperature having the least effect. The last objective of the study was to profile the maize output trend for the period from 1937 to 2018. The main findings from the analysis indicate that maize production in South Africa has a general upward slope. The study recommends that the government should intensify the provision of irrigation systems for the farmers in the most vulnerable areas to mitigate the climate change. Government should also embark on massive campaigns using a variety of media to create the needed public awareness on climate change and its impact on food security. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
Organophosphate flame retardant’s signatures in the Buffalo River Estuary and their removal using modified cyclodextrins
- Authors: Bika, Sinozuko Hope
- Date: 2022-03
- Subjects: Water purification chemicals industry , Organic water pollutants , Rivers
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27500 , vital:67363
- Description: The increasing scarcity of fresh and clean water in many places around the world is a major concern. Water is a basic need that must be availed to humans, plants and animals at any given time. It is a requirement that each human on earth should get between 20-50 L of fresh, clean and pure water a day. It is very difficult to keep up with this need due to drastic increase in global pollution by emerging contaminants. The increase is due to human activities, modern way of life, industrialization and improper disposal of materials that contain these OPFRs. Organophosphate flame retardants OPFRs are the organic pollutants considered in this study. OPFRs are semi volatile compounds SVOCs that are used in many industries as flame retardants and additives. They were developed because of environmental and health concerns of previously used brominated and chlorinated flame retardants FRs. They show acute toxicity and exhibit adverse effects such as neurotoxicity, they are also carcinogenic to humans and animals. In recent years, some researchers have started investigating the occurrence and distribution of OPFRs in South African rivers. The aim of this study was to identify signatures of OPFRs in the aquatic environment of Buffalo River Estuary, and soil from a nearby dumpsite: and to develop a method for their removal using modified cyclodextrins. In this study, the concentration of OPFRs were investigated in sediments and soil samples collected from Buffalo River Estuary. This estuary is located close to a major port in East London city in the Eastern Cape Province, South Africa. Collection of samples was done across two seasons i.e. winter and spring. OPFRs in sediment and soil samples in this study were extracted using ultrasonic extraction method. Solid-phase extraction SPE was employed for the cleanup of the extracts, in order to reduce potential matrix interference and also for sample purification. The congeners of interest in this study were Tris 2-Choroethyl phosphate TCEP and Tris 1,3-Dicloro-2-propyl phosphate (TDCP). Samples were air dried immediately on arrival at the laboratory after being stored in an ice chest at 4 ℃ and further processed for further analysis.The concentrations of OPFRs were determined using GC-μECD (gas chromatograph coupled with micro electron capture detector) from soil and sediments in that area and they were found high in winter compared to spring owing to high level of discharge of industrial and domestic waste into the aquatic system and also the nearby dumpsite. The total concentrationof OPFRs Ʃ 2OPFRs for sediments and soil for both seasons was 39935±7619 μg/g and 10376±601 μg/g, respectively. The dominant congener in the Buffalo River Estuary was TCEP. The ecological risk assessment was estimated for the study area, and TCEP moderate risk while TDCP presented low risk. From this study, it could be inferred that the Buffalo River Estuary and the nearby dumpsite in East London are polluted by emerging pollutants i.e. OPFRs. Hence, strict control measures should be put in place to monitor all activities contributing to such magnitude of pollution in the estuary, which is of great economic value to the country. Furthermore in this study, an insoluble and hydrophilic polymer EDTA-Cysteine-β-Cyclodextrin was prepared and synthesized for the remediation of OPFRs in soil and sediments. This newly developed method was tested for the removal of TDCP an OPFR congener and it was successful with an average removal rate of 77.49 percent. , Thesis (MSci) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Authors: Bika, Sinozuko Hope
- Date: 2022-03
- Subjects: Water purification chemicals industry , Organic water pollutants , Rivers
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27500 , vital:67363
- Description: The increasing scarcity of fresh and clean water in many places around the world is a major concern. Water is a basic need that must be availed to humans, plants and animals at any given time. It is a requirement that each human on earth should get between 20-50 L of fresh, clean and pure water a day. It is very difficult to keep up with this need due to drastic increase in global pollution by emerging contaminants. The increase is due to human activities, modern way of life, industrialization and improper disposal of materials that contain these OPFRs. Organophosphate flame retardants OPFRs are the organic pollutants considered in this study. OPFRs are semi volatile compounds SVOCs that are used in many industries as flame retardants and additives. They were developed because of environmental and health concerns of previously used brominated and chlorinated flame retardants FRs. They show acute toxicity and exhibit adverse effects such as neurotoxicity, they are also carcinogenic to humans and animals. In recent years, some researchers have started investigating the occurrence and distribution of OPFRs in South African rivers. The aim of this study was to identify signatures of OPFRs in the aquatic environment of Buffalo River Estuary, and soil from a nearby dumpsite: and to develop a method for their removal using modified cyclodextrins. In this study, the concentration of OPFRs were investigated in sediments and soil samples collected from Buffalo River Estuary. This estuary is located close to a major port in East London city in the Eastern Cape Province, South Africa. Collection of samples was done across two seasons i.e. winter and spring. OPFRs in sediment and soil samples in this study were extracted using ultrasonic extraction method. Solid-phase extraction SPE was employed for the cleanup of the extracts, in order to reduce potential matrix interference and also for sample purification. The congeners of interest in this study were Tris 2-Choroethyl phosphate TCEP and Tris 1,3-Dicloro-2-propyl phosphate (TDCP). Samples were air dried immediately on arrival at the laboratory after being stored in an ice chest at 4 ℃ and further processed for further analysis.The concentrations of OPFRs were determined using GC-μECD (gas chromatograph coupled with micro electron capture detector) from soil and sediments in that area and they were found high in winter compared to spring owing to high level of discharge of industrial and domestic waste into the aquatic system and also the nearby dumpsite. The total concentrationof OPFRs Ʃ 2OPFRs for sediments and soil for both seasons was 39935±7619 μg/g and 10376±601 μg/g, respectively. The dominant congener in the Buffalo River Estuary was TCEP. The ecological risk assessment was estimated for the study area, and TCEP moderate risk while TDCP presented low risk. From this study, it could be inferred that the Buffalo River Estuary and the nearby dumpsite in East London are polluted by emerging pollutants i.e. OPFRs. Hence, strict control measures should be put in place to monitor all activities contributing to such magnitude of pollution in the estuary, which is of great economic value to the country. Furthermore in this study, an insoluble and hydrophilic polymer EDTA-Cysteine-β-Cyclodextrin was prepared and synthesized for the remediation of OPFRs in soil and sediments. This newly developed method was tested for the removal of TDCP an OPFR congener and it was successful with an average removal rate of 77.49 percent. , Thesis (MSci) -- Faculty of Science and Agriculture, 2022
- Full Text:
Perceptions and determinants of genetically modified (GM) maize production among rural households: The case of Ngqushwa Local Municipality, South Africa
- Zamisa, Owethu https://orcid.org/0000-0002-7303-4469
- Authors: Zamisa, Owethu https://orcid.org/0000-0002-7303-4469
- Date: 2022-03
- Subjects: Genetically modified foods , Agricultural biotechnology , Sustainable agriculture -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22479 , vital:52343
- Description: Rural South Africa is faced with immense challenges including poverty, unemployment, low agriculture productivity, food and nutritional insecurity and inequalities. Against this background, enhancing rural agricultural productivity using proven technologies such as genetically modified (GM) maize production is suggested as a pathway to economic development and poverty reduction. Literature suggests that GM technology can increase crop yields, drought tolerance, reduced weeding labour costs and chemical spray costs. However, GM maize varieties available on the market currently were created to fit large-scale, capital-intensive, industrialised, and economically oriented agricultural systems. As a result, their uptake has been significantly slow especially in rural areas where several stakeholders are now questioning the potential of GM technology. With that background, this study aimed to understand determinants of gm maize production among rural farming households and their perceptions using the case of Ngqushwa Local Municipality. Specifically, the study sought to analyse types of maize varieties grown by rural households, associated yields, area allocation, rural households’ perceptions of GM maize, and to estimate factors that influence GM maize awareness, participation and intensity of production among this subsector. Using a cross-sectional survey research design, a sample size of 400 households was randomly selected and interviewed using a semi-structured questionnaire. The types of maize varieties grown by rural households, associated yields, area allocation and rural households’ perceptions of GM maize were analysed using descriptive statistics. Factors that influence GM maize awareness, participation, and intensity of production were estimated using a triple hurdle model where the 1st and 2nd hurdle were estimated using Probit regression, and 3rd hurdle a Tobit regression. The study revealed that landrace maize varieties are currently the most popular maize varieties grown by the majority of rural farming households from the study area producing higher yields (0.6t/ha) as compared to other hybrids (GM – 0.5t/ha, conventional hybrids -0.3t/ha and improved OPVs – 0.1t/ha). Descriptive statistics results also indicated that farming households from the study area allocated more land to landrace maize varieties (42percent) compared to other maize varieties (GM maize (30percent), hybrids (21percent) and improved OPVs (7percent) further supporting the notion that landrace maize varieties dominate the rural farming subsector. Perception results revealed that the majority (57percent) of the households perceived GM maize as an expensive variety which, however, has a potential to produce relatively higher yields than other hybrids on the market and eliminates several production problems (manual weeding, pest spraying) making farm management easier. Findings further indicate that the majority (52percent) of the farming households from the study area did not have sufficient knowledge of GM maize. Econometrics results revealed that GM maize awareness is negatively influenced by age and gender and positively influenced by marital status, employment status and number of years in school. Conditional on awareness of GM maize varieties, both participation and intensity of participation in GM maize production are positively influenced by land size, gender, group membership, size of arable land and negatively influenced by employment status and income. Against this background, the study concludes that farming households from the study area produced more compared to the other varieties. Furthermore, the study concludes that households get higher yields from landrace maize varieties and allocate more of their land to landrace maize production. In addition, the study also concludes that most rural farmers perceive participation in GM maize as beneficial especially towards elimination of farm management problems, produces higher yields, and makes farm management easier. Lastly, the study concludes that GM maize awareness is negatively influenced by age and gender and positively influenced by marital status, employment status and number of years in school. Both participation and intensity of participation in GM maize production are positively influenced by land size, gender, group membership, arable land and negatively influenced by employment status and income. The study recommends that priority should be given to these socio-economic and institutional factors and this may be addressed by targeting GM maize awareness campaigns and platforms more suited to female-headed, older, lowly educated and unemployed rural farming households. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Authors: Zamisa, Owethu https://orcid.org/0000-0002-7303-4469
- Date: 2022-03
- Subjects: Genetically modified foods , Agricultural biotechnology , Sustainable agriculture -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22479 , vital:52343
- Description: Rural South Africa is faced with immense challenges including poverty, unemployment, low agriculture productivity, food and nutritional insecurity and inequalities. Against this background, enhancing rural agricultural productivity using proven technologies such as genetically modified (GM) maize production is suggested as a pathway to economic development and poverty reduction. Literature suggests that GM technology can increase crop yields, drought tolerance, reduced weeding labour costs and chemical spray costs. However, GM maize varieties available on the market currently were created to fit large-scale, capital-intensive, industrialised, and economically oriented agricultural systems. As a result, their uptake has been significantly slow especially in rural areas where several stakeholders are now questioning the potential of GM technology. With that background, this study aimed to understand determinants of gm maize production among rural farming households and their perceptions using the case of Ngqushwa Local Municipality. Specifically, the study sought to analyse types of maize varieties grown by rural households, associated yields, area allocation, rural households’ perceptions of GM maize, and to estimate factors that influence GM maize awareness, participation and intensity of production among this subsector. Using a cross-sectional survey research design, a sample size of 400 households was randomly selected and interviewed using a semi-structured questionnaire. The types of maize varieties grown by rural households, associated yields, area allocation and rural households’ perceptions of GM maize were analysed using descriptive statistics. Factors that influence GM maize awareness, participation, and intensity of production were estimated using a triple hurdle model where the 1st and 2nd hurdle were estimated using Probit regression, and 3rd hurdle a Tobit regression. The study revealed that landrace maize varieties are currently the most popular maize varieties grown by the majority of rural farming households from the study area producing higher yields (0.6t/ha) as compared to other hybrids (GM – 0.5t/ha, conventional hybrids -0.3t/ha and improved OPVs – 0.1t/ha). Descriptive statistics results also indicated that farming households from the study area allocated more land to landrace maize varieties (42percent) compared to other maize varieties (GM maize (30percent), hybrids (21percent) and improved OPVs (7percent) further supporting the notion that landrace maize varieties dominate the rural farming subsector. Perception results revealed that the majority (57percent) of the households perceived GM maize as an expensive variety which, however, has a potential to produce relatively higher yields than other hybrids on the market and eliminates several production problems (manual weeding, pest spraying) making farm management easier. Findings further indicate that the majority (52percent) of the farming households from the study area did not have sufficient knowledge of GM maize. Econometrics results revealed that GM maize awareness is negatively influenced by age and gender and positively influenced by marital status, employment status and number of years in school. Conditional on awareness of GM maize varieties, both participation and intensity of participation in GM maize production are positively influenced by land size, gender, group membership, size of arable land and negatively influenced by employment status and income. Against this background, the study concludes that farming households from the study area produced more compared to the other varieties. Furthermore, the study concludes that households get higher yields from landrace maize varieties and allocate more of their land to landrace maize production. In addition, the study also concludes that most rural farmers perceive participation in GM maize as beneficial especially towards elimination of farm management problems, produces higher yields, and makes farm management easier. Lastly, the study concludes that GM maize awareness is negatively influenced by age and gender and positively influenced by marital status, employment status and number of years in school. Both participation and intensity of participation in GM maize production are positively influenced by land size, gender, group membership, arable land and negatively influenced by employment status and income. The study recommends that priority should be given to these socio-economic and institutional factors and this may be addressed by targeting GM maize awareness campaigns and platforms more suited to female-headed, older, lowly educated and unemployed rural farming households. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
Synthesis and evaluation of pyrene grafted onto zinc oxide nanoparticles for the removal of organic contaminants from wastewater
- Authors: Samuel, Zipho
- Date: 2022-03
- Subjects: Land treatment of wastewater , Zinc oxide , Water pollution control industry
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27754 , vital:69407
- Description: Drinking water scarcity is a global crisis even though water covers about three quarters of the earth. One of the major causes of this scarcity is water pollution, which is a result of human activities. This has been noticed and reported for a number of years but is still unsolved and intensifying. Hence, scientists are busy trying to find solutions to this global menace. In this study, zinc oxide nanoparticles were synthesised via co-precipitation, a cost reasonable method and functionalized by grafting a pyrene ligand on its surface in order to provide a scaffold to which many other functionalities can be adsorbed. By so doing, the efficiency and capacity of bare nanoparticles is improved. The synthesised pyrene ligand was successfully characterised with nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscope (FTIR). The adsorbent was characterized using X-ray diffractometer (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), FTIR, energy dispersive x-ray (EDX) and thermogravimetric analyzer (TGA). The choice of zinc oxide nanoparticles as preferred adsorbent was due to their exceptional properties including large surface area, thermal and chemical stabilities. These properties are the reason zinc oxide nanoparticles possess high adsorption efficiency and capacity. The results of characterization indicated a decreased particle size and improved thermal stabilities of the pyrene grafted zinc oxide nanoparticles compared to the zinc oxide nanoparticles, showing that this material can be employed even at higher temperatures. The average particle size of the bare nanoparticles decreased from 290 to 181 nm after functionalization. Thermal stability increased from 550oC in the bare nanoparticles to 650oC in the functionalized nanoparticles. Characteristic reflections of zinc oxide nanoparticles in the XRD analysis were maintained even after functionalization However, diffractogram roughness was noticed for the functionalized nanoparticles due to the introduction of the amorphous layer from the ligand. This novel material was employed for the removal of an herbicide, simazine as well as two dyes, methyl violet and brilliant green from aqueous solutions by batch adsorption experiments. The kinetics and isotherm studies of the different adsorption processes were carried out by using three of the commonly used kinetic and isotherm models (pseudo-first order, intraparticle diffusion and pseudo-second order) and (Langmuir, Temkin isotherms and Freundlich) respectively. From all batch adsorption experiments conducted for simazine removal, the adsorbent showed effectiveness and high adsorption capacity for the removal of simazine. The highest observed efficiency and capacity were 71.3 percent and 137 mg/g respectively at pH equals 2, time equals 60 minutes, adsorbent dose equals 20 mg and adsorbate conc equals 0. 281 mg/L. Kinetics study for the adsorption of simazine favoured pseudo-first order. However, Langmuir isotherm could also be applicable to understand the adsorption process. The material also showed reusability potential of up to three cycles for this contaminant indicating that this material can be re-used. In the case of the removal of methyl violet from aqueous solution, the adsorbent showed a reasonable adsorption maximum capacity (qmax) (31.5 mg/g) at contact time equals 360 min, adsorbent dose approximately equals 40 mg, temperature equals 20 plus 2oC and pH equals 6.5, when compared to other adsorbents previously reported for the removal of methyl violet (MV) in literature. Kinetics and isotherm studies indicated that the process for the removal of this pollutant with this pyrene grafted onto zinc oxide nanoparticles proceeded via pseudo-first order (R2 equals 0.931) and Langmuir isotherm models (R2 equals 0.980) respectively. These results indicated that this material could serve as alternate material to already established materials for the removal of recalcitrant organic pollutants from aqueous solutions. Moreover, the adsorbent also showed reusability potential for this contaminant. Similarly, the adsorbent showed high removal efficiency and capacity in all batch adsorption experiments for brilliant green (BG) adsorption. The highest adsorption efficiency of 88.8 percent was accomplished with 79.8 mg at pH 6.50 and temperature of 20 equals 2oC within 360 minutes. BG adsorption rate mechanism was best explained by the pseudo-first order kinetic model (R2 equals 0.903). Dye adsorption behaviour was best explained using Langmuir isotherm (R2 equals 0.980). Reusability of the adsorbent showed that the adsorbent is efficient after three runs. The overall results of adsorption by a way of comparison of the adsorption capacity of this novel material with respect to the contaminants is in this trend: brilliant green greater methyl violet greater simazine. This study indicates that this novel material can serve as new material for the removal of herbicides and dyes as well as vast variety of pollutants from wastewater considering its high adsorption efficiency and its recyclability. Thus, industries can explore the use of this material for the removal of varying pollutants from wastewater. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Authors: Samuel, Zipho
- Date: 2022-03
- Subjects: Land treatment of wastewater , Zinc oxide , Water pollution control industry
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27754 , vital:69407
- Description: Drinking water scarcity is a global crisis even though water covers about three quarters of the earth. One of the major causes of this scarcity is water pollution, which is a result of human activities. This has been noticed and reported for a number of years but is still unsolved and intensifying. Hence, scientists are busy trying to find solutions to this global menace. In this study, zinc oxide nanoparticles were synthesised via co-precipitation, a cost reasonable method and functionalized by grafting a pyrene ligand on its surface in order to provide a scaffold to which many other functionalities can be adsorbed. By so doing, the efficiency and capacity of bare nanoparticles is improved. The synthesised pyrene ligand was successfully characterised with nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscope (FTIR). The adsorbent was characterized using X-ray diffractometer (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), FTIR, energy dispersive x-ray (EDX) and thermogravimetric analyzer (TGA). The choice of zinc oxide nanoparticles as preferred adsorbent was due to their exceptional properties including large surface area, thermal and chemical stabilities. These properties are the reason zinc oxide nanoparticles possess high adsorption efficiency and capacity. The results of characterization indicated a decreased particle size and improved thermal stabilities of the pyrene grafted zinc oxide nanoparticles compared to the zinc oxide nanoparticles, showing that this material can be employed even at higher temperatures. The average particle size of the bare nanoparticles decreased from 290 to 181 nm after functionalization. Thermal stability increased from 550oC in the bare nanoparticles to 650oC in the functionalized nanoparticles. Characteristic reflections of zinc oxide nanoparticles in the XRD analysis were maintained even after functionalization However, diffractogram roughness was noticed for the functionalized nanoparticles due to the introduction of the amorphous layer from the ligand. This novel material was employed for the removal of an herbicide, simazine as well as two dyes, methyl violet and brilliant green from aqueous solutions by batch adsorption experiments. The kinetics and isotherm studies of the different adsorption processes were carried out by using three of the commonly used kinetic and isotherm models (pseudo-first order, intraparticle diffusion and pseudo-second order) and (Langmuir, Temkin isotherms and Freundlich) respectively. From all batch adsorption experiments conducted for simazine removal, the adsorbent showed effectiveness and high adsorption capacity for the removal of simazine. The highest observed efficiency and capacity were 71.3 percent and 137 mg/g respectively at pH equals 2, time equals 60 minutes, adsorbent dose equals 20 mg and adsorbate conc equals 0. 281 mg/L. Kinetics study for the adsorption of simazine favoured pseudo-first order. However, Langmuir isotherm could also be applicable to understand the adsorption process. The material also showed reusability potential of up to three cycles for this contaminant indicating that this material can be re-used. In the case of the removal of methyl violet from aqueous solution, the adsorbent showed a reasonable adsorption maximum capacity (qmax) (31.5 mg/g) at contact time equals 360 min, adsorbent dose approximately equals 40 mg, temperature equals 20 plus 2oC and pH equals 6.5, when compared to other adsorbents previously reported for the removal of methyl violet (MV) in literature. Kinetics and isotherm studies indicated that the process for the removal of this pollutant with this pyrene grafted onto zinc oxide nanoparticles proceeded via pseudo-first order (R2 equals 0.931) and Langmuir isotherm models (R2 equals 0.980) respectively. These results indicated that this material could serve as alternate material to already established materials for the removal of recalcitrant organic pollutants from aqueous solutions. Moreover, the adsorbent also showed reusability potential for this contaminant. Similarly, the adsorbent showed high removal efficiency and capacity in all batch adsorption experiments for brilliant green (BG) adsorption. The highest adsorption efficiency of 88.8 percent was accomplished with 79.8 mg at pH 6.50 and temperature of 20 equals 2oC within 360 minutes. BG adsorption rate mechanism was best explained by the pseudo-first order kinetic model (R2 equals 0.903). Dye adsorption behaviour was best explained using Langmuir isotherm (R2 equals 0.980). Reusability of the adsorbent showed that the adsorbent is efficient after three runs. The overall results of adsorption by a way of comparison of the adsorption capacity of this novel material with respect to the contaminants is in this trend: brilliant green greater methyl violet greater simazine. This study indicates that this novel material can serve as new material for the removal of herbicides and dyes as well as vast variety of pollutants from wastewater considering its high adsorption efficiency and its recyclability. Thus, industries can explore the use of this material for the removal of varying pollutants from wastewater. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
Threatened plant species in Vhembe Biosphere Reserve, Limpopo province, South Africa: Problems and prospects of conservation and utilization
- Ramarumo, Luambo Jeffrey https://orcid.org/0000-0002-2393-6982
- Authors: Ramarumo, Luambo Jeffrey https://orcid.org/0000-0002-2393-6982
- Date: 2022-03
- Subjects: Plants -- Extinction , Rare plants , Botany, Economic
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/22754 , vital:52738
- Description: Threatened plant species are those species that are vulnerable or at the risk of extinction. According to Version 3.1 of the International Union for Conservation of Nature (IUCN)’s Red List Categories and Criteria, the three categories of threat in order of increasing risk of extinction are: Vulnerable (VU), Endangered (EN) and Critically Endangered (CR). These species are oftenly protected by both national and international obligations. Scientific evidence suggests that threatened plants are disappearing at an alarming rate. The current expansion of agricultural land, urbanization, over-exploitation of biological resources, climate change and invasive alien species are regarded as major drivers of biodiversity loss and high rate of species extinction worldwide. Scientists and conservation managers are seeking to understand and monitor plant species that are likely to be on the verge of extinction. Monitoring of threatened plants can be better achieved through insights about indigenous knowledge dynamics associated with such species. Scientific scholars including botanists, ethnobotanists, conservationists and anthropologists, all share common interest about the use of indigenous knowledge for livelihoods, scientific and economic growth. As a result, there is a growing interest on indigenous knowledge researches, particularly involving utilization and conservation of plant species. Given the fact that recent scientific evidence suggests that such studies are lacking in South African Biosphere Reserves, as well as the fact that scientist and conservation managers are seeking to understand species likely to be on the verge of extinction risk. It is within this context that this study is aimed at investigating threatened plant species utilization, conservation statuses and distribution in the Vhembe Biosphere Reserve, Limpopo Province in South Africa. The hypothesis of this study states that traditional knowledge about utilization, distribution and conservation statuses of threatened plant species provide suggestions for appropriate conservation practices. Since the current study is ethnobotanical in nature that is focusing on human interactions with plants, the research methods used addressed multidisciplinary aspects and involved disciplinary integration. An integrated participatory research approach focusing on shared learning, forging collaborative relations with participants, analyzing and validating the shared knowledge was used to document ethnobotanical data within the study area. This research approach was selected as it is considered to be a quick and effective way of acquiring data associated with indigenous knowledge systems. To offset the elements of bias during data collection, the research technique was designed to accommodate core principles that interlinked participatory rural appraisal (PRA) and rapid rural appraisal (RRA). Furthermore, the integrated core principles of participatory rural appraisal and rapid rural appraisal were used with conventional methods such as field surveys and interviews using questionnaires. Therefore, ethnobotanical data were collected through interviews with 203 participants. The data associated with threatened plant’s population size were gathered through literal counting of individual plants as per the IUCN’s Red List Criteria. Data associated with the conservation statuses were gathered from both the South African National Biodiversity Institute and IUCN databases. A total of 13 useful threatened plants belonging to 12 families were recorded with their conservation statuses ranging from being Vulnerable to Critically Endangered. The majority of the threatened plant species (46.0percent) were used for medicinal purposes only, followed by species used for medicinal purposes and as ornamentals (23.0percent). The frequently cited useful threatened species with use values (UV) > 0.024, relative frequency citation (RFC) > 0.059 and fidelity level percentage (FLpercent) > 5.911percent, included Asparagus sekukuniensis, Bowiea volubilis, Brackenridgea zanguebarica, Ocotea bullata, Rhynchosia vendae, Siphonochilus aethiopicus and Warburgia salutaris. About 47.0percent of the recorded useful threatened plants were distributed in remote areas of the Thathe Vonḓo and its surroundings. Threatened plants with population size < 100 adult individuals constituted the majority (61.54percent). Birdlime-making plant species were also documented in the current study. A total of 12 birdlime-making plants belonging to six families were recorded, including threatened Huernia nouhuysii, which is categorized as Vulnerable in South Africa. Amongst the recorded families, Loranthaceae and Euphorbiaceae were categorized as the most frequently utilized families. Among the recorded species, six of them were reported to being used in the birdlime-making for the first time and these species include Euphorbia pulvinata (17.2percent), followed by Tapinanthus forbesii (8percent), Tapinanthus rubromarginatus (7.2percent), Erianthemum ngamicum (7.2percent), Englerophytum magalismon-tanum (3.6percent), Huernia nouhuysii (2.0percent), and Euphorbia tirucalli (0.8percent). Only three plant parts were utilized for birdlime-making. The milky latex was preferred plant part (58.3percent), followed by fruit (33.3percent) and root bark (8.4percent). Birdlime-making techniques involved crushing, which accounted for 55.7percent, followed by air blown (29.6percent) and boiling (14.7percent). Furthermore, the complementary contribution of birdlime toward human development included, being used for bird hunting or trapping small birds (45.8percent), adhesion (23.2percent), teeth cleaning (17.2percent) and roof-waterproofing (13.8percent). The indigenous conservation strategies employed by participants included harvesting of single lateral root per individual medicinal plant (15.3percent), medicinal and timber materials are only harvested during winter season (16.7percent), the use of moist soil to cover injured plant part after bark harvest (18.2percent), prohibit harvesting of and/ or from an injured plant (11.8percent), collection of dried or fallen plants for firewood (8.4percent), issuing of permits by traditional council through the chief or headman to allow collection of medicinal materials and timber (9.9percent), prohibit chopping down of medicinal plant species (13.8percent) and collection of some Critically Endangered plant species such as Brackenridgea zanguebarica and Siphonochilus aethiopicus during the night by authorized people only (5.9percent). The hypothesis which stated that traditional knowledge about utilization, distribution and conservation statuses of threatened plant species provide suggestions for appropriate conservation practices can therefore, not be rejected as there is room for further and more detailed ethnobotanical investigations that is focused on human interactions with threatened plant species. The data presented in this thesis could be used as baseline information for formulating new conservation strategies, monitoring and management plans of threatened plant species not only in the Vhembe Biosphere Reserve, but in other regions of South African. This study provided insights associated with ethnomedicinal uses of Asparagus sekukuniensis, Protea laetans and Encephalartos hirsutus. Results of this study could also stimulate interest in other scientific disciplines such as the phytochemistry, pharmacology, bioprocessing, conservation and anthropology involving documentation threatened plant species. , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Authors: Ramarumo, Luambo Jeffrey https://orcid.org/0000-0002-2393-6982
- Date: 2022-03
- Subjects: Plants -- Extinction , Rare plants , Botany, Economic
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/22754 , vital:52738
- Description: Threatened plant species are those species that are vulnerable or at the risk of extinction. According to Version 3.1 of the International Union for Conservation of Nature (IUCN)’s Red List Categories and Criteria, the three categories of threat in order of increasing risk of extinction are: Vulnerable (VU), Endangered (EN) and Critically Endangered (CR). These species are oftenly protected by both national and international obligations. Scientific evidence suggests that threatened plants are disappearing at an alarming rate. The current expansion of agricultural land, urbanization, over-exploitation of biological resources, climate change and invasive alien species are regarded as major drivers of biodiversity loss and high rate of species extinction worldwide. Scientists and conservation managers are seeking to understand and monitor plant species that are likely to be on the verge of extinction. Monitoring of threatened plants can be better achieved through insights about indigenous knowledge dynamics associated with such species. Scientific scholars including botanists, ethnobotanists, conservationists and anthropologists, all share common interest about the use of indigenous knowledge for livelihoods, scientific and economic growth. As a result, there is a growing interest on indigenous knowledge researches, particularly involving utilization and conservation of plant species. Given the fact that recent scientific evidence suggests that such studies are lacking in South African Biosphere Reserves, as well as the fact that scientist and conservation managers are seeking to understand species likely to be on the verge of extinction risk. It is within this context that this study is aimed at investigating threatened plant species utilization, conservation statuses and distribution in the Vhembe Biosphere Reserve, Limpopo Province in South Africa. The hypothesis of this study states that traditional knowledge about utilization, distribution and conservation statuses of threatened plant species provide suggestions for appropriate conservation practices. Since the current study is ethnobotanical in nature that is focusing on human interactions with plants, the research methods used addressed multidisciplinary aspects and involved disciplinary integration. An integrated participatory research approach focusing on shared learning, forging collaborative relations with participants, analyzing and validating the shared knowledge was used to document ethnobotanical data within the study area. This research approach was selected as it is considered to be a quick and effective way of acquiring data associated with indigenous knowledge systems. To offset the elements of bias during data collection, the research technique was designed to accommodate core principles that interlinked participatory rural appraisal (PRA) and rapid rural appraisal (RRA). Furthermore, the integrated core principles of participatory rural appraisal and rapid rural appraisal were used with conventional methods such as field surveys and interviews using questionnaires. Therefore, ethnobotanical data were collected through interviews with 203 participants. The data associated with threatened plant’s population size were gathered through literal counting of individual plants as per the IUCN’s Red List Criteria. Data associated with the conservation statuses were gathered from both the South African National Biodiversity Institute and IUCN databases. A total of 13 useful threatened plants belonging to 12 families were recorded with their conservation statuses ranging from being Vulnerable to Critically Endangered. The majority of the threatened plant species (46.0percent) were used for medicinal purposes only, followed by species used for medicinal purposes and as ornamentals (23.0percent). The frequently cited useful threatened species with use values (UV) > 0.024, relative frequency citation (RFC) > 0.059 and fidelity level percentage (FLpercent) > 5.911percent, included Asparagus sekukuniensis, Bowiea volubilis, Brackenridgea zanguebarica, Ocotea bullata, Rhynchosia vendae, Siphonochilus aethiopicus and Warburgia salutaris. About 47.0percent of the recorded useful threatened plants were distributed in remote areas of the Thathe Vonḓo and its surroundings. Threatened plants with population size < 100 adult individuals constituted the majority (61.54percent). Birdlime-making plant species were also documented in the current study. A total of 12 birdlime-making plants belonging to six families were recorded, including threatened Huernia nouhuysii, which is categorized as Vulnerable in South Africa. Amongst the recorded families, Loranthaceae and Euphorbiaceae were categorized as the most frequently utilized families. Among the recorded species, six of them were reported to being used in the birdlime-making for the first time and these species include Euphorbia pulvinata (17.2percent), followed by Tapinanthus forbesii (8percent), Tapinanthus rubromarginatus (7.2percent), Erianthemum ngamicum (7.2percent), Englerophytum magalismon-tanum (3.6percent), Huernia nouhuysii (2.0percent), and Euphorbia tirucalli (0.8percent). Only three plant parts were utilized for birdlime-making. The milky latex was preferred plant part (58.3percent), followed by fruit (33.3percent) and root bark (8.4percent). Birdlime-making techniques involved crushing, which accounted for 55.7percent, followed by air blown (29.6percent) and boiling (14.7percent). Furthermore, the complementary contribution of birdlime toward human development included, being used for bird hunting or trapping small birds (45.8percent), adhesion (23.2percent), teeth cleaning (17.2percent) and roof-waterproofing (13.8percent). The indigenous conservation strategies employed by participants included harvesting of single lateral root per individual medicinal plant (15.3percent), medicinal and timber materials are only harvested during winter season (16.7percent), the use of moist soil to cover injured plant part after bark harvest (18.2percent), prohibit harvesting of and/ or from an injured plant (11.8percent), collection of dried or fallen plants for firewood (8.4percent), issuing of permits by traditional council through the chief or headman to allow collection of medicinal materials and timber (9.9percent), prohibit chopping down of medicinal plant species (13.8percent) and collection of some Critically Endangered plant species such as Brackenridgea zanguebarica and Siphonochilus aethiopicus during the night by authorized people only (5.9percent). The hypothesis which stated that traditional knowledge about utilization, distribution and conservation statuses of threatened plant species provide suggestions for appropriate conservation practices can therefore, not be rejected as there is room for further and more detailed ethnobotanical investigations that is focused on human interactions with threatened plant species. The data presented in this thesis could be used as baseline information for formulating new conservation strategies, monitoring and management plans of threatened plant species not only in the Vhembe Biosphere Reserve, but in other regions of South African. This study provided insights associated with ethnomedicinal uses of Asparagus sekukuniensis, Protea laetans and Encephalartos hirsutus. Results of this study could also stimulate interest in other scientific disciplines such as the phytochemistry, pharmacology, bioprocessing, conservation and anthropology involving documentation threatened plant species. , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
- Full Text:
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