Synthesis of modified zinc oxide nanoparticles using pneumatic spray pyrolysis for solar cell application
- Authors: Ntozakhe, Luyolo
- Date: 2017
- Subjects: Zinc oxide -- Synthesis Nanoparticles
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/5862 , vital:29408
- Description: In this work, the pneumatic spray pyrolysis was used to synthesize un-doped and carbon doped zinc oxide (ZnO) nanoparticles. The zinc acetate, tetrabutylammonium bromide and ethanol were used as starting materials for the desired ZnO nanoparticles and the prepared samples were annealed at 400 oC in the furnace. The as synthesized un-doped and carbon doped ZnO NPs were evaluated using X-ray diffraction (XRD), Scanning electron microscope (SEM), Energy dispersive x-ray spectroscopy (EDX), High-resolution transmission electron microscopy (HRTEM), Raman spectroscopy (RS) and Ultraviolet-visible spectroscopy (UV-Vis). XRD analysis of the synthesized NPs revealed peaks at 31.90°, 34.50°, 36.34°, 47.73°, 56.88°, 63.04°, 68.20°, and 77.33° belonging to the hexagonal Wurtzite ZnO crystal structure. The incorporation of C species into ZnO lattice was cross examined by monitoring the peak positions of the (100), (002) and (001) planes. These three main peaks of C-ZnO NPs show a peak shift to higher 2θ values which indicates substitutional carbon doping in ZnO NPs. SEM analysis has revealed that the as synthesized NPs have spherical shape and the morphology of the NPs change as the concentration of carbon increases. The EDX spectra of both un-doped and doped ZnO nanoparticles have revealed prominent peaks at 0.51 keV, 1.01 keV, 1.49 keV, 8.87 keV and 9.86 keV. Peaks at, X-ray energies of 0.51 keV and 1.01 keV respectively represent the emissions from the K-shell of oxygen and L-shell of zinc. The L-shell emission at 1.01 keV is considered as convolution of Zn 2p3/2 and Zn 2p1/2 photoelectron energies. The occurrence of these peaks in the EDX endorses the existence of Zn and O atoms in the PSP prepared samples. HRTEM analysis has revealed NPs size modal range from 6.65-14.21 nm for the PSP synthesized samples which is in mutual agreement with the XRD data calculated values. More over the selected area diffraction images displaying the fact that only the diffraction planes of (101), (002) and (100) are responsible for the diffraction pattern belonging to Wurtzite ZnO. RS analysis has revealed that the un-doped ZnO and doped ZnO samples have characteristic Raman vibration modes at 325 cm-1, and 434 cm-1 belonging to Wurtzite ZnO structure. Moreover, the prominent peak at 434 cm-1 which is the characteristic peak of E2(2) (high) mode of the Wurtzite ZnO and the E2(2) (high) has been red shifted by 4 cm-1, as compared to that found in the bulk ZnO. Additionally, the effect of carbon doping through Raman spectroscopy peak shifts of the E2(2) (high) mode, A1(LO) mode and multi-phonon has also been considered and discussed in detail. UV-Vis diffuse reflectance spectroscopy has revealed a red shift of the absorption edge with increase in C doping. Finally, the effect of nano-crystallite size and gradual prominence of C into ZnO lattice due to increase in C doping concentration in the PSP prepared nanoparticles was meticulously elaborated through Raman Spectroscopy analysis.
- Full Text:
- Authors: Ntozakhe, Luyolo
- Date: 2017
- Subjects: Zinc oxide -- Synthesis Nanoparticles
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/5862 , vital:29408
- Description: In this work, the pneumatic spray pyrolysis was used to synthesize un-doped and carbon doped zinc oxide (ZnO) nanoparticles. The zinc acetate, tetrabutylammonium bromide and ethanol were used as starting materials for the desired ZnO nanoparticles and the prepared samples were annealed at 400 oC in the furnace. The as synthesized un-doped and carbon doped ZnO NPs were evaluated using X-ray diffraction (XRD), Scanning electron microscope (SEM), Energy dispersive x-ray spectroscopy (EDX), High-resolution transmission electron microscopy (HRTEM), Raman spectroscopy (RS) and Ultraviolet-visible spectroscopy (UV-Vis). XRD analysis of the synthesized NPs revealed peaks at 31.90°, 34.50°, 36.34°, 47.73°, 56.88°, 63.04°, 68.20°, and 77.33° belonging to the hexagonal Wurtzite ZnO crystal structure. The incorporation of C species into ZnO lattice was cross examined by monitoring the peak positions of the (100), (002) and (001) planes. These three main peaks of C-ZnO NPs show a peak shift to higher 2θ values which indicates substitutional carbon doping in ZnO NPs. SEM analysis has revealed that the as synthesized NPs have spherical shape and the morphology of the NPs change as the concentration of carbon increases. The EDX spectra of both un-doped and doped ZnO nanoparticles have revealed prominent peaks at 0.51 keV, 1.01 keV, 1.49 keV, 8.87 keV and 9.86 keV. Peaks at, X-ray energies of 0.51 keV and 1.01 keV respectively represent the emissions from the K-shell of oxygen and L-shell of zinc. The L-shell emission at 1.01 keV is considered as convolution of Zn 2p3/2 and Zn 2p1/2 photoelectron energies. The occurrence of these peaks in the EDX endorses the existence of Zn and O atoms in the PSP prepared samples. HRTEM analysis has revealed NPs size modal range from 6.65-14.21 nm for the PSP synthesized samples which is in mutual agreement with the XRD data calculated values. More over the selected area diffraction images displaying the fact that only the diffraction planes of (101), (002) and (100) are responsible for the diffraction pattern belonging to Wurtzite ZnO. RS analysis has revealed that the un-doped ZnO and doped ZnO samples have characteristic Raman vibration modes at 325 cm-1, and 434 cm-1 belonging to Wurtzite ZnO structure. Moreover, the prominent peak at 434 cm-1 which is the characteristic peak of E2(2) (high) mode of the Wurtzite ZnO and the E2(2) (high) has been red shifted by 4 cm-1, as compared to that found in the bulk ZnO. Additionally, the effect of carbon doping through Raman spectroscopy peak shifts of the E2(2) (high) mode, A1(LO) mode and multi-phonon has also been considered and discussed in detail. UV-Vis diffuse reflectance spectroscopy has revealed a red shift of the absorption edge with increase in C doping. Finally, the effect of nano-crystallite size and gradual prominence of C into ZnO lattice due to increase in C doping concentration in the PSP prepared nanoparticles was meticulously elaborated through Raman Spectroscopy analysis.
- Full Text:
The contribution of communal sheep production to household welfare in Nyadeni local municipality under alternative extension regimes
- Authors: Ngqulana, Athenkosi
- Date: 2017
- Subjects: Sheep -- Breeding -- South Africa -- Eastern Cape Communal rangelands -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MAgric
- Identifier: http://hdl.handle.net/10353/13270 , vital:39629
- Description: Sheep farming seems to have a rich profile in the improvement of the livelihoods in the deprived parts of developing countries throughout the world. The broad objective of this study is to assess the contribution of sheep production to household welfare under alternative extension regimes. Specifically, this research investigated the methods used to deliver extension services, perceptions of communal sheep farmers towards extension delivery services and contribution of communal sheep production to household welfare. The study was conducted in Nyandeni Local Municipality in the Eastern Cape Province and employed survey data obtained from 105 households practising sheep production. Cross-sectional research design and purposive sampling technique was used. Descriptive statistics was used to examine socio-economic characteristics and extension methods used to improve sheep production. Likert scale was used to rate perceptions of sheep producers and extension services given And a T-test analyses was conducted to test its reliability. Linear multiple regression model was used to estimate the contribution of sheep production to rural household’s welfare. The descriptive statistics results show that males were dominant with a representation of 55.2 percent and 44.8 percent were females. Moreover, the majority of households were aged, being above 61 years on average. The results showed high levels of illiteracy amongst household sheep producers with 54 percent having no formal education and average number of years farmers spent in school was 7 years and less. About 62 percent of the households were married and 54 percent was found to be unemployed. Farming was found to be the major agricultural economic activity. The results also shows that there is one type of extension method used in the area which was the group method through the use of group meetings. This finding was surprising as it was different from the results that were expected given prior information obtained from the literature and extension service. Therefore the study was unable to conclude on which of the extension method was most effective since the households were not exposed to different regimes. From the Likert-scale analysis, although all households received extension services many (58 percent) of respondents were not satisfied with the services they received. In order to run the regression, diagnostic checks were done to check if multicollinearity existed in the variables. Linear multiple regression analysis results indicate that sheep production contributes to household income and welfare. However, household sheep production was influenced by a number of factors such as educational level, household size, number of sheep sold and sheep price while age was found to adversely affect sheep production in the study area. Farmers require to be trained on sheep production and necessary methods required for sheep production as to increase percent received extension services many (58 percent) of respondents were not satisfied with the services they received. In order to run the regression, diagnostic checks were done to check if multicollinearity existed in the variables. Linear multiple regression analysis results indicate that sheep production contributes to household income and welfare. However, household sheep production was influenced by a number of factors such as educational level, household size, number of sheep sold and sheep price while age was found to adversely affect sheep production in the study area. Farmers require to be trained on sheep production and necessary methods required for sheep production as to increase their household income and welfare through the improvement of the factors that affected sheep significantly. Also since the farmers were exposed on one regime there is a need for extension agents to use more than one extension regime to improve production.
- Full Text:
- Authors: Ngqulana, Athenkosi
- Date: 2017
- Subjects: Sheep -- Breeding -- South Africa -- Eastern Cape Communal rangelands -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MAgric
- Identifier: http://hdl.handle.net/10353/13270 , vital:39629
- Description: Sheep farming seems to have a rich profile in the improvement of the livelihoods in the deprived parts of developing countries throughout the world. The broad objective of this study is to assess the contribution of sheep production to household welfare under alternative extension regimes. Specifically, this research investigated the methods used to deliver extension services, perceptions of communal sheep farmers towards extension delivery services and contribution of communal sheep production to household welfare. The study was conducted in Nyandeni Local Municipality in the Eastern Cape Province and employed survey data obtained from 105 households practising sheep production. Cross-sectional research design and purposive sampling technique was used. Descriptive statistics was used to examine socio-economic characteristics and extension methods used to improve sheep production. Likert scale was used to rate perceptions of sheep producers and extension services given And a T-test analyses was conducted to test its reliability. Linear multiple regression model was used to estimate the contribution of sheep production to rural household’s welfare. The descriptive statistics results show that males were dominant with a representation of 55.2 percent and 44.8 percent were females. Moreover, the majority of households were aged, being above 61 years on average. The results showed high levels of illiteracy amongst household sheep producers with 54 percent having no formal education and average number of years farmers spent in school was 7 years and less. About 62 percent of the households were married and 54 percent was found to be unemployed. Farming was found to be the major agricultural economic activity. The results also shows that there is one type of extension method used in the area which was the group method through the use of group meetings. This finding was surprising as it was different from the results that were expected given prior information obtained from the literature and extension service. Therefore the study was unable to conclude on which of the extension method was most effective since the households were not exposed to different regimes. From the Likert-scale analysis, although all households received extension services many (58 percent) of respondents were not satisfied with the services they received. In order to run the regression, diagnostic checks were done to check if multicollinearity existed in the variables. Linear multiple regression analysis results indicate that sheep production contributes to household income and welfare. However, household sheep production was influenced by a number of factors such as educational level, household size, number of sheep sold and sheep price while age was found to adversely affect sheep production in the study area. Farmers require to be trained on sheep production and necessary methods required for sheep production as to increase percent received extension services many (58 percent) of respondents were not satisfied with the services they received. In order to run the regression, diagnostic checks were done to check if multicollinearity existed in the variables. Linear multiple regression analysis results indicate that sheep production contributes to household income and welfare. However, household sheep production was influenced by a number of factors such as educational level, household size, number of sheep sold and sheep price while age was found to adversely affect sheep production in the study area. Farmers require to be trained on sheep production and necessary methods required for sheep production as to increase their household income and welfare through the improvement of the factors that affected sheep significantly. Also since the farmers were exposed on one regime there is a need for extension agents to use more than one extension regime to improve production.
- Full Text:
The effect of gold price volatility on stock market returns in South Africa
- Authors: Gcadana, Nqabisa Mary
- Date: 2017
- Subjects: Stock exchanges --South Africa.
- Language: English
- Type: Thesis , Masters , MCom (Economics)
- Identifier: http://hdl.handle.net/10353/13359 , vital:39637
- Description: The South African stock market has become a major player in the African Securities Exchanges Association through its performance. Gold is one of the commodities that are traded at Johannesburg Stock Exchange, hence gold price fluctuations are the crucial factor that JSE needs to keep its eye on. The demand for gold in South Africa is continuously rising because gold has full security, less credit risk and is a highly liquid instrument. Based on the given background, the study examines the effect of gold price volatility on stock market returns in South Africa, employing the Generalised Autoregressive Conditional Heteroskedasticity (GARCH) (1.1) model. The study used monthly data covering the period from 2005 to 2017. The Storage model and discounted cash flows model which are the theories that connect gold price and stock market were specified. The research findings are supported by previous studies. The gold price volatility was found to have a negative effect on stock market returns, and the proxy of stock market returns is the All Share Index. The study will help to provide an understanding of how gold price volatility affects the stock market that will help policymakers to come up with policies that are relevant to volatility of gold price towards stock market.
- Full Text:
- Authors: Gcadana, Nqabisa Mary
- Date: 2017
- Subjects: Stock exchanges --South Africa.
- Language: English
- Type: Thesis , Masters , MCom (Economics)
- Identifier: http://hdl.handle.net/10353/13359 , vital:39637
- Description: The South African stock market has become a major player in the African Securities Exchanges Association through its performance. Gold is one of the commodities that are traded at Johannesburg Stock Exchange, hence gold price fluctuations are the crucial factor that JSE needs to keep its eye on. The demand for gold in South Africa is continuously rising because gold has full security, less credit risk and is a highly liquid instrument. Based on the given background, the study examines the effect of gold price volatility on stock market returns in South Africa, employing the Generalised Autoregressive Conditional Heteroskedasticity (GARCH) (1.1) model. The study used monthly data covering the period from 2005 to 2017. The Storage model and discounted cash flows model which are the theories that connect gold price and stock market were specified. The research findings are supported by previous studies. The gold price volatility was found to have a negative effect on stock market returns, and the proxy of stock market returns is the All Share Index. The study will help to provide an understanding of how gold price volatility affects the stock market that will help policymakers to come up with policies that are relevant to volatility of gold price towards stock market.
- Full Text:
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