No description available.

Thesis (M.S.)--Wisconsin. / Includes bibliographical references (leaves 84-85).

Thesis (M.S.)--California Polytechnic State University, 2009. / Mode of access: Internet. Title from PDF title page; viewed on Jan. 7, 2010. Major professor: Dr. Sean Hurley. "Presented to the faculty of California Polytechnic State University, San Luis Obispo." "In partial fulfillment of the requirements for the degree of Master of Science in Agribusiness." "December 2009." Includes bibliographical references (p. 75-77).

Costs saving measures are important for South African gold producers due to increasing energy costs and decreasing production volumes. Demand Side Management (DSM) is an effective strategy to reduce electricity consumption and costs. DSM projects have been implemented widely on South African mining systems such as pumping, refrigeration, rock transport and compressed air. Implementations have, however, been limited on gold processing plants despite the significant amounts of energy that this section consumes. The main objective of gold processing plants is production orientated and energy management is not a primary focus. This rationale is re-evaluated owing to high electricity price inflation and availability of DSM incentives. This study investigated the cost saving potential of DSM interventions on gold plants. Electrical load management was identified as a key opportunity that can deliver substantial cost savings. These savings were shown to be feasible in respect of the required capital expenditure, effort of implementation and maintenance of operational targets. Investigation procedures were compiled to identify feasible load management opportunities. The most potential for electricity cost savings was identified on comminution equipment. Consequently, a methodology was developed to implement electrical load management on the identified sections. The methodology proposed simulation techniques that enabled load management and subsequent electricity cost optimisation through production planning. Two electrical load management case studies were successfully implemented on comminution equipment at two gold processing plants. Peak period load shift of 3.6 MW and 0.6 MW, respectively, was achieved on average for a period of three months. The annual cost savings of these applications could amount to R1.4-million and R 660 000. This results in specific electricity cost reductions of 3% and 7% for the two respective case studies. Results from the two case studies are an indication of potential for electrical load management on South African gold processing plants. If an average electricity cost saving of 5% is extrapolated across the South African gold processing industry, the potential cost savings amount to R 25-million per annum. Although the costs saving opportunities are feasible, it is influenced by the reliability of the equipment and the dynamics of ore supply. This insight plays a decisive role in determining the feasibility of DSM on gold processing plants. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2015

Costs saving measures are important for South African gold producers due to increasing energy costs and decreasing production volumes. Demand Side Management (DSM) is an effective strategy to reduce electricity consumption and costs. DSM projects have been implemented widely on South African mining systems such as pumping, refrigeration, rock transport and compressed air. Implementations have, however, been limited on gold processing plants despite the significant amounts of energy that this section consumes. The main objective of gold processing plants is production orientated and energy management is not a primary focus. This rationale is re-evaluated owing to high electricity price inflation and availability of DSM incentives. This study investigated the cost saving potential of DSM interventions on gold plants. Electrical load management was identified as a key opportunity that can deliver substantial cost savings. These savings were shown to be feasible in respect of the required capital expenditure, effort of implementation and maintenance of operational targets. Investigation procedures were compiled to identify feasible load management opportunities. The most potential for electricity cost savings was identified on comminution equipment. Consequently, a methodology was developed to implement electrical load management on the identified sections. The methodology proposed simulation techniques that enabled load management and subsequent electricity cost optimisation through production planning. Two electrical load management case studies were successfully implemented on comminution equipment at two gold processing plants. Peak period load shift of 3.6 MW and 0.6 MW, respectively, was achieved on average for a period of three months. The annual cost savings of these applications could amount to R1.4-million and R 660 000. This results in specific electricity cost reductions of 3% and 7% for the two respective case studies. Results from the two case studies are an indication of potential for electrical load management on South African gold processing plants. If an average electricity cost saving of 5% is extrapolated across the South African gold processing industry, the potential cost savings amount to R 25-million per annum. Although the costs saving opportunities are feasible, it is influenced by the reliability of the equipment and the dynamics of ore supply. This insight plays a decisive role in determining the feasibility of DSM on gold processing plants. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2015

Amostras de leite \'in natura\'coletados de diferentes latões foram analisadas por espectrofotometria de absorção atômica com forno de grafite, para determinação dos níveis residuais de cádmio, tendo sido selecionados latões com pontos de solda(L1), latões velhos(L2) e latões reestanhados(L3), perfazendo um total de 59 amostras, sendo o seguinte os valores médios encontrados: Latões com pontos de solda: 0,0169 ppm Latões velhos: 0,0168 ppm Latões reestanhados 0,0118 ppm Não foram encontradas diferenças significativas nos níveis residuais de cádmio considerando-se os diferentes tipos de latões, tendo-se efetuado o teste de Significância entre duas médias a um nível de garantia de 95 %. Os valores absolutos estiveram entre 0,0500 ppm e 0,0020 ppm de cádmio. Avaliaram-se os valores residuais de cádmio, considerando-se apenas a origem do leite, ou seja a propriedade rural, tendo-se observado valores médios variando de 0,0080 ppm a 0,0272 ppm. Foram encontradas diferenças significativas entre os níveis residuais de cádmio nas amostras de leite levando-se em conta a origem do produto. Coletaram-se amostras de leite de 05 animais diretamente na propriedade rural, e o valor médio encontrado foi de 0,01738 ppm, mais elevado do que a média encontrada nos diferentes latões. Pelos valores determinados por outros autores em diferentes países, quando comparados com os resultados da presente pesquisa, pode-se supor que os níveis aqui detectados, embora dentro dos padrões da legislação brasileira, podem estar elevados, colocando em risco a saúde de crianças e pessoas debilitadas, tendo em vista o potencial do metal pesado se acumular no organismo, causando-lhe danos irreversíveis. O autor sugere maiores pesquisas sobre os níveis residuais de metais pesados em órgãos de animais abatidos, utilizados na alimentação humana e na fabricação de rações animais. Sugere ainda pesquisas abrangentes nos adubos fosfóricos utilizados nas plantações e levantamentos epidemiológicos nas populações rurais que consomem produtos diretamente das propriedades onde ocorrem as contaminações. Não foram encontradas as fontes de contaminação do leite, porém vários autores asseveraram que pode estar ocorrendo uma contaminação natural de plantas e animais decorrentes do uso de produtos contaminados com metais pesados, podendo ainda ser uma contaminação casual e até do próprio solo, contaminado pelo cádmio. / A total of 64 samples of raw milk collected in a processing plant were analysed for the determination of cadmium levels, using the Atomic Absorption Spectrophotometry attached to a Carbon Rod atomizer.The cans used for milk transportation were selected as follow: soldered cans, older cans and tinned cans. The mean average of cadmium levels in milk sanples were: soldered cans- 0,0169 ppm, older cans- 0,0168 ppm tinned cans 0,0118 ppm There were no statistical differences amongst the cadmium levels in milk from different cans. The cadmium levels in milk were analysed to verify the statistical differences amongst the sites of production, and the mean values ranged from 0,0272 ppm to 0,0020 ppm. Statistical differences in cadmium levels related to the different sites of production were found. Samples of cows milk were collected and analysed for cadmium determination, and mean average level was 0,01738 ppm., higher tham the mean average levels from different cans. The mean cadmium values from this issue , and the values reported by other authors in papers ,allow us to say that probably the cadmium levels found in milk samples might be hight specially for children and older persons. These levels may be a Public Health hazard to those who consume products from animal sources The author suggests that more issues to determine the metal levels in animal organs consumed by the population and used for animal feedstuff should be made. In attempt to an epidemiological study in the population that uses milk and others products from farms, more studies should be made. Sources of milk contamination were not found, and authors claimmed that these metals are present in plants and soil with an unknown origin, probably due to environmental contamination.

Amostras de leite \'in natura\'coletados de diferentes latões foram analisadas por espectrofotometria de absorção atômica com forno de grafite, para determinação dos níveis residuais de cádmio, tendo sido selecionados latões com pontos de solda(L1), latões velhos(L2) e latões reestanhados(L3), perfazendo um total de 59 amostras, sendo o seguinte os valores médios encontrados: Latões com pontos de solda: 0,0169 ppm Latões velhos: 0,0168 ppm Latões reestanhados 0,0118 ppm Não foram encontradas diferenças significativas nos níveis residuais de cádmio considerando-se os diferentes tipos de latões, tendo-se efetuado o teste de Significância entre duas médias a um nível de garantia de 95 %. Os valores absolutos estiveram entre 0,0500 ppm e 0,0020 ppm de cádmio. Avaliaram-se os valores residuais de cádmio, considerando-se apenas a origem do leite, ou seja a propriedade rural, tendo-se observado valores médios variando de 0,0080 ppm a 0,0272 ppm. Foram encontradas diferenças significativas entre os níveis residuais de cádmio nas amostras de leite levando-se em conta a origem do produto. Coletaram-se amostras de leite de 05 animais diretamente na propriedade rural, e o valor médio encontrado foi de 0,01738 ppm, mais elevado do que a média encontrada nos diferentes latões. Pelos valores determinados por outros autores em diferentes países, quando comparados com os resultados da presente pesquisa, pode-se supor que os níveis aqui detectados, embora dentro dos padrões da legislação brasileira, podem estar elevados, colocando em risco a saúde de crianças e pessoas debilitadas, tendo em vista o potencial do metal pesado se acumular no organismo, causando-lhe danos irreversíveis. O autor sugere maiores pesquisas sobre os níveis residuais de metais pesados em órgãos de animais abatidos, utilizados na alimentação humana e na fabricação de rações animais. Sugere ainda pesquisas abrangentes nos adubos fosfóricos utilizados nas plantações e levantamentos epidemiológicos nas populações rurais que consomem produtos diretamente das propriedades onde ocorrem as contaminações. Não foram encontradas as fontes de contaminação do leite, porém vários autores asseveraram que pode estar ocorrendo uma contaminação natural de plantas e animais decorrentes do uso de produtos contaminados com metais pesados, podendo ainda ser uma contaminação casual e até do próprio solo, contaminado pelo cádmio. / A total of 64 samples of raw milk collected in a processing plant were analysed for the determination of cadmium levels, using the Atomic Absorption Spectrophotometry attached to a Carbon Rod atomizer.The cans used for milk transportation were selected as follow: soldered cans, older cans and tinned cans. The mean average of cadmium levels in milk sanples were: soldered cans- 0,0169 ppm, older cans- 0,0168 ppm tinned cans 0,0118 ppm There were no statistical differences amongst the cadmium levels in milk from different cans. The cadmium levels in milk were analysed to verify the statistical differences amongst the sites of production, and the mean values ranged from 0,0272 ppm to 0,0020 ppm. Statistical differences in cadmium levels related to the different sites of production were found. Samples of cows milk were collected and analysed for cadmium determination, and mean average level was 0,01738 ppm., higher tham the mean average levels from different cans. The mean cadmium values from this issue , and the values reported by other authors in papers ,allow us to say that probably the cadmium levels found in milk samples might be hight specially for children and older persons. These levels may be a Public Health hazard to those who consume products from animal sources The author suggests that more issues to determine the metal levels in animal organs consumed by the population and used for animal feedstuff should be made. In attempt to an epidemiological study in the population that uses milk and others products from farms, more studies should be made. Sources of milk contamination were not found, and authors claimmed that these metals are present in plants and soil with an unknown origin, probably due to environmental contamination.

No description available.

Thesis (doctoral)--Helsinki University of Technology, 2007. / Includes bibliographical references. Also available on the World Wide Web.

Thesis (Ph. D.)--Ohio State University, 2008. / Title from first page of PDF file. Includes bibliographical references (p. 79-86).