Effect of scanning speed on the laser metal deposited ti-6al-2sn-2mo-2cr-0,25si alloy
- Authors: Boshoman, Salaminah Bonolo
- Date: 2019
- Language: English
- Type: Master (Thesis)
- Identifier: http://hdl.handle.net/10210/399039 , uj:33245
- Description: Abstract : Please refer to full text to view abstract. , M.Tech. (Mechanical Engineering)
- Full Text:
- Authors: Boshoman, Salaminah Bonolo
- Date: 2019
- Language: English
- Type: Master (Thesis)
- Identifier: http://hdl.handle.net/10210/399039 , uj:33245
- Description: Abstract : Please refer to full text to view abstract. , M.Tech. (Mechanical Engineering)
- Full Text:
The development of a dendrimer-gold nanocomposite electrochemical sensor for the detection of lead (ii) ion in water
- Authors: Mokgwadi, Jalda Kgaogelo
- Date: 2019
- Subjects: Nanocomposites (Materials) , Electrochemical sensors , Drinking water|xLead content , Nanoscience
- Language: English
- Type: Master (Thesis)
- Identifier: http://hdl.handle.net/10210/401397 , uj:33543
- Description: Abstract : In South Africa, industrial development and mining sustain the economy. Unfortunately, the effluents from these industries introduce heavy metal pollutants such as lead (Pb2+) into the environmental water. Pb2+ is widely recognized as one of the highly toxic and non-biodegradable metal that poses serious health problems and even death. This study presents a method of heavy metal analysis by modifying glassy carbon electrode (GCE) with gold nanoparticles (AuNPs) and generation 2 (G2) poly(propyleneimine) dendrimer (PPI) to provide a highly sensitive electrochemical sensor for the determination of Pb2+ ions in water using square wave anodic stripping voltammetry (SWASV). The co-deposition of PPI and AuNPs on the surface of GCE was confirmed by atomic force microscopy (AFM). Voltammetric probing showed that the GCE-PPI/AuNPs platform exhibited reversible electrochemistry and conductivity in [Fe(CN)6]3 −/4 – redox probe. The electroactive surface area of the bare GCE, GCE-PPI, GCE-AuNPs and GCE-PPI/AuNPs were also estimated in order to illustrate that the prepared PPI/AuNPs nanocomposite could improve the surface area and conductivity of the GCE and was found to be 8.17 mm2 for bare GCE, 10.84 mm2 for GCE-PPI, 11.03 mm2 for GCE-AuNPs and 11.13 mm2 for GCE-PPI/AuNPs. The electroactive surface area of GCE-PPI/AuNPs modified electrode increased by approximately 36.23% as compared to bare GCE, which provided an effective evidence for the superior conductivity of PPI/AuNPs as expected. The effect of different electrochemical parameters on the sensitivity of the sensor for the Pb2+ detection was also scrutinized, including supporting electrolyte (HNO3), deposition potential (-800 mV) and deposition time (150s). The sensor was applied in the detection of different standard concentrations of Pb2+, linear range of (1 ppb-100 ppb) with detection limit of 0.96 ppb. The GCE-PPI/AuNPs sensor was then applied to detect Pb2+ in tap water whose results were validated with ICP-OES. , M.Sc. (Nanoscience)
- Full Text:
- Authors: Mokgwadi, Jalda Kgaogelo
- Date: 2019
- Subjects: Nanocomposites (Materials) , Electrochemical sensors , Drinking water|xLead content , Nanoscience
- Language: English
- Type: Master (Thesis)
- Identifier: http://hdl.handle.net/10210/401397 , uj:33543
- Description: Abstract : In South Africa, industrial development and mining sustain the economy. Unfortunately, the effluents from these industries introduce heavy metal pollutants such as lead (Pb2+) into the environmental water. Pb2+ is widely recognized as one of the highly toxic and non-biodegradable metal that poses serious health problems and even death. This study presents a method of heavy metal analysis by modifying glassy carbon electrode (GCE) with gold nanoparticles (AuNPs) and generation 2 (G2) poly(propyleneimine) dendrimer (PPI) to provide a highly sensitive electrochemical sensor for the determination of Pb2+ ions in water using square wave anodic stripping voltammetry (SWASV). The co-deposition of PPI and AuNPs on the surface of GCE was confirmed by atomic force microscopy (AFM). Voltammetric probing showed that the GCE-PPI/AuNPs platform exhibited reversible electrochemistry and conductivity in [Fe(CN)6]3 −/4 – redox probe. The electroactive surface area of the bare GCE, GCE-PPI, GCE-AuNPs and GCE-PPI/AuNPs were also estimated in order to illustrate that the prepared PPI/AuNPs nanocomposite could improve the surface area and conductivity of the GCE and was found to be 8.17 mm2 for bare GCE, 10.84 mm2 for GCE-PPI, 11.03 mm2 for GCE-AuNPs and 11.13 mm2 for GCE-PPI/AuNPs. The electroactive surface area of GCE-PPI/AuNPs modified electrode increased by approximately 36.23% as compared to bare GCE, which provided an effective evidence for the superior conductivity of PPI/AuNPs as expected. The effect of different electrochemical parameters on the sensitivity of the sensor for the Pb2+ detection was also scrutinized, including supporting electrolyte (HNO3), deposition potential (-800 mV) and deposition time (150s). The sensor was applied in the detection of different standard concentrations of Pb2+, linear range of (1 ppb-100 ppb) with detection limit of 0.96 ppb. The GCE-PPI/AuNPs sensor was then applied to detect Pb2+ in tap water whose results were validated with ICP-OES. , M.Sc. (Nanoscience)
- Full Text:
The economic impact of the Dobsonville Shopping Centre on the quality of lives of the local community
- Authors: Moerane, K. K.
- Date: 2019
- Subjects: Economic development - South Africa - Gauteng , Shopping centers - South Africa - Gauteng
- Language: English
- Type: Master (Thesis)
- Identifier: http://hdl.handle.net/10210/403329 , uj:33793
- Description: Abstract : This research project falls within the sphere of local economic development. With worldwide spending patterns on a constant increase, there is a demand for access to goods and services. For these goods and services consumers demand that their access be convenient and comfortable; shopping centres are built to address this demand by providing a convenient and comfortable retail structure for the customer’s benefit. This research project examined the economic impact of retail structures on the quality of lives of the local community, specifically the Dobsonville community in Soweto. The Dobsonville Shopping Centre was the first mall to be built in Soweto. It is a beacon of the first signs of economic development in the democratic South Africa. The retail sector has been identified as a factor that will aid in the economic development of the Soweto region. The objective of this research project was to establish the influence of the Dobsonville Shopping Centre on the quality of lives of the community. The literature review explored social and economic factors on the local economic development level. This was done by defining local economic development in the context of the retail structures and its related theories. These were the Central Place Theory and the Lift Cycle of Retail Development Theory; these place retail developments as the starting point and potential regenerator of local economic development. A survey was conducted with 60 Dobsonville community members and secondary data from StatsSA was used to determine the economic impact of the Dobsonville Shopping Centre on their quality of life. It was not conclusive if the Dobsonville Shopping Centre had any significant economic impact on the community in the areas of household income and employment. A secondary conclusion arising from the research project was that malls make communities more attractive for investment initiatives, thus effecting the economics of an area, thereby improving the quality of lives of community members. Shopping centres influence the community members’ iv perceptions of their local environment; thus, retail developments could be catalysts for investment and local economic development within this community. , M.Com. (Local Economic Development)
- Full Text:
- Authors: Moerane, K. K.
- Date: 2019
- Subjects: Economic development - South Africa - Gauteng , Shopping centers - South Africa - Gauteng
- Language: English
- Type: Master (Thesis)
- Identifier: http://hdl.handle.net/10210/403329 , uj:33793
- Description: Abstract : This research project falls within the sphere of local economic development. With worldwide spending patterns on a constant increase, there is a demand for access to goods and services. For these goods and services consumers demand that their access be convenient and comfortable; shopping centres are built to address this demand by providing a convenient and comfortable retail structure for the customer’s benefit. This research project examined the economic impact of retail structures on the quality of lives of the local community, specifically the Dobsonville community in Soweto. The Dobsonville Shopping Centre was the first mall to be built in Soweto. It is a beacon of the first signs of economic development in the democratic South Africa. The retail sector has been identified as a factor that will aid in the economic development of the Soweto region. The objective of this research project was to establish the influence of the Dobsonville Shopping Centre on the quality of lives of the community. The literature review explored social and economic factors on the local economic development level. This was done by defining local economic development in the context of the retail structures and its related theories. These were the Central Place Theory and the Lift Cycle of Retail Development Theory; these place retail developments as the starting point and potential regenerator of local economic development. A survey was conducted with 60 Dobsonville community members and secondary data from StatsSA was used to determine the economic impact of the Dobsonville Shopping Centre on their quality of life. It was not conclusive if the Dobsonville Shopping Centre had any significant economic impact on the community in the areas of household income and employment. A secondary conclusion arising from the research project was that malls make communities more attractive for investment initiatives, thus effecting the economics of an area, thereby improving the quality of lives of community members. Shopping centres influence the community members’ iv perceptions of their local environment; thus, retail developments could be catalysts for investment and local economic development within this community. , M.Com. (Local Economic Development)
- Full Text:
- «
- ‹
- 1
- ›
- »