M.Sc. (Zoology) / Please refer to full text to view abstract

This study aimed to determine the applicability of western migration models to the movement patterns of foreign migrant traders at the Hartebeespoort Dam. After reflecting on theoretical dimensions of migration and the informal sector, an overview was provided of the historical development of migration patterns to and within South Africa. The complex nature of migration phenomena ensures the application of qualitative and quantitative research methodologies. A snowball sampling technique was used to select 30 respondents for the purpose of the questionnaire survey. Information obtained from this survey was supplemented by five in-depth interviews. Descriptive statistical techniques were used to analyse the information obtained from the survey. The study concluded that western migration models do not offer adequate explanation for the migration patterns observed among foreign migrant traders at the Hartebeespoort Dam. The study also established the merit of the combined use of qualitative and quantitative research methodologies in migration studies. / Geography / M.A. (Geography)

This study aimed to determine the applicability of western migration models to the movement patterns of foreign migrant traders at the Hartebeespoort Dam. After reflecting on theoretical dimensions of migration and the informal sector, an overview was provided of the historical development of migration patterns to and within South Africa. The complex nature of migration phenomena ensures the application of qualitative and quantitative research methodologies. A snowball sampling technique was used to select 30 respondents for the purpose of the questionnaire survey. Information obtained from this survey was supplemented by five in-depth interviews. Descriptive statistical techniques were used to analyse the information obtained from the survey. The study concluded that western migration models do not offer adequate explanation for the migration patterns observed among foreign migrant traders at the Hartebeespoort Dam. The study also established the merit of the combined use of qualitative and quantitative research methodologies in migration studies. / Geography / M.A. (Geography)

The suitability of water hyacinth in biogas production was evaluated as a means of waste management in the interests of sustainable energy production. Batch anaerobic digestion (AD) of water hyacinth was conducted to determine the optimal pre-treatment method for maximum methane production. Physical pre-treatment methods produced a highest cumulative methane of 2.3 L during batch AD. The selected pre-treatment method, hand-cutting, was further evaluated in a semi-continuous AD using both mono- and co-digestion. The emphasis was on identifying microbial communities involved and their response to organic loading rates (OLRs). The Illumina Miseq results proved that bacterial communities were more sensitive to disturbances caused by irregular OLRs as compared to archaeal communities. In addition, the variation in substrate nutrients as a result of mono- and co-digestion of water hyacinth, contributed to variations in the bacterial diversity. For example, Bacteroides and Petrimonas diversity varied between mono- and co-digestion. Overall, the study verified that water hyacinth is a suitable feedstock for biogas production and the simple pre-treatment methods are recommended. Furthermore, OLRs influenced the microbial community structure and associated biogas yield. / National Research Foundation (South Africa) / Environmental Science / M. Sc. (Environmental Science)