published_or_final_version / Chemistry / Master / Master of Philosophy

published_or_final_version / Chemistry / Master / Master of Philosophy

published_or_final_version / Chemistry / Master / Master of Philosophy

No description available.

No description available.

A multichannel detection system based on a linear photodiode array (PDA) is described. The design and construction of the detection system and a rapid slew-scan computer-controlled stepping motor grating drive system is detailed. The theoretical performance of an optimized PDA system is contrasted with the performance of photomultiplier tubes. A technique is described which allows the dynamic range of the PDA to be extended by one order of magnitude towards higher light levels. A wavelength calibration procedure is outlined which results in a wavelength prediction accuracy of (+OR-)0.003 nm. A theory for high resolution spatial image positioning is presented and the ability to detect varying degrees of spectral overlap is evaluated. Applications of the PDA to the measurement and characterization of transient signals is described.

No description available.

This study concerns the origin of a porphyry copper deposit. For the study 25 rock samples were taken from a porphyry copper deposit. Rock samples were analyzed for these trace elements: strontium, barium, copper, zinc, and vanadium. The results indicated that elevation correlations are not apparent for copper, zinc, and vanadium content, but definite correlations appear between strontium and barium content. This study determined that strontium is one of the trace elements which could be used as a possible exploration guide to porphyry copper mineralization. This study also provided that distribution of trace elements demonstrates the presence of a regional difference in the strontium and barium contents of the sample locations between the Dome Peak Quadrangle area and the Agnes Mountain area of the Cloudy Pass batholith; the volcanics of the former possess higher levels of strontium and barium concentrations.

Please read the abstract in the section 00front of this document / Dissertation (MSc (Chemistry))--University of Pretoria, 2006. / Chemistry / unrestricted

The accumulation of metal contaminants in the human environment has received a great deal of attention during the last several years as it has become apparent that their presence, in excess, represents a threat to human health. Biochemical assays to determine concentrations of metals in the human body have used such tissues as blood, bone, hair, nails and, more recently, teeth. The present study attempts to provide further evidence for the use of deciduous teeth as indicators of human exposure to concentrations of lead, copper and zinc as a result of ore smelting operations in Kamloops and Trail, British Columbia. Kamloops represents an area of minimum exposure to smelter operations in contrast to Trail where a lead/zinc smelter has been operating for many years. Concentrations of lead, copper and zinc in deciduous teeth from geographically-stable Kamloops children, aged 5 years to 12 years, were compared to concentrations found in a similar population of geographically-stable Trail children. Whole teeth were digested in nitric and perchloric acids and trace element concentrations were determined using inductively coupled plasma emission spectroscopy. Mean lead and zinc concentrations for Kamloops and Trail teeth, respectively, were: 31.6 ± 7.33 ppm and 48.2. ± 11.5 ppm for lead (p < 0.05) and 103.4 ± 23.6 ppm and 111.9 ± 15.4 ppm for zinc. Copper was undetectable at < 1 ppm in all teeth. Locally-grown foods from each area and foods grown elsewhere were also analyzed for lead, copper and zinc in an effort to establish the possible contribution of these elements from local food resources in Kamloops and Trail. Twenty-four hour diet composites were collected and analyzed for copper and zinc by atomic absorption spectroscopy. Mean copper and zinc concentrations for foods grown in Kamloops and Trail, respectively, were: 1.5 ± 0.4 ppm and 1.6 ± 0.9 ppm for copper and 3. 2 ± 1.3 ppm and 3.1 ± 0.9 ppm for zinc. Mean copper and zinc concentrations for non-locally grown foods collected from Kamloops and Trail, respectively, were: 1.1 ± 0.2 ppm and 1.6 ± 0.8 ppm for copper and 5.8 ± 1.9 ppm and 6.5 ± 0.3 ppm for zinc. Lead was determined by plasma emission spectroscopy, and was found to be undetectable at < 1 ppm in all food samples. To assess the extent of maximal consumption of locally-grown foods, selected home gardeners in the Brocklehurst district of Kamloops and the Genelle district of Trail were interviewed. Seasonal consumption and home food preservation practices were determined. In addition, 24-hour diet recalls were obtained from 177 Brocklehurst district children in September and April, 1977-78 to determine "typical" eating patterns of these children. . The amount of locally-grown foods consumed was dependent mainly on season of the year; however, choice of food by the children on the whole did not differ from fall to spring. The recalls also indicated that males consumed more food than females, particularly protein. Meals, especially breakfast, were frequently missed, and non-nutritious snacks were common to the diets of many of the children. Results from this study indicated that, although deciduous tooth lead concentrations were significantly (p<0.05) higher in Trail than in Kamloops, samples of locally-grown foods obtained in 1978 from these two communities were not excessively high in lead, zinc or copper. In fact, these elements in foods compared well to concentrations reported in other areas of North America. It would appear, then, that the higher concentrations of lead in Trail teeth are a result of increased intake from other environmental sources. Analyses of food consumption patterns of gardening families revealed that local foods comprised an important part of the diet. Measures should be taken to ensure the continued safety of foods in areas where mineral mining and smelting occur. / Land and Food Systems, Faculty of / Graduate