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Thesis (M.S.)--Brigham Young University. Dept. of Physics and Astronomy, 2003. / Includes bibliographical references (p. 57-59).

High-energy ion beam based proton induced x-ray (PIXE) is an ideal analytical tool suitable for simultaneous quantification of trace elements with high accuracy. The quantification of trace elements in solids using PIXE has been well established for over two decades. The main objective of this study is to extend this capability to solids with an inhomogeneous internal structure. In this study, pure GAC and PAC samples were soaked in known concentration of arsenic (As) solution and the trace amount of As uptake was determined during these exposures using PIXE, neutron activation analysis (NAA) and atomic absorption spectroscopy (AAS). There is a good agreement between the values and adsorption mechanisms derived from the NAA and pelletised PIXE measurements and some AAS measurements. Micro-PIXE was used to understand the discrepancies in the As adsorption on the pore and flat surfaces of GAC samples. / Master of Science (Hons) (Physics)

Mercury is an environmental contaminant that preferentially accumulates in the kidney. It has been previously shown using proton-induced X-ray emission analysis that mercury (HgCl2) accumulated in precision-cut rabbit renal cortical slices. In this study, the efficacy of seven chelating agents for the removal of Hg from renal dices has been examined. Rabbits were injected with HgCl2 (10 mg/kg) and 3 h later kidneys were sliced, or renal slices were exposed in vitro to a mildly toxic concentration of HgCl2 (5 x 10-5 M, 4 h). The slices were then treated in vitro with 10 mM concentrations of EDTA, lipoic acid (LA), penicillamine (PA), glutathione (GSH), 1,4-dithiothreitol (DTT), DMSA, or DMPS. DMPS proved to be the most effective in mobilizing Hg from in vivo or in vitro HgCl2-exposed renal tissue (>85% of control after 3 h incubation). Relative efficacies for the seven agents were DMPS > DMSA, PA > DTT, GSH > LA, EDTA. The use of renal slices appears to be a useful in vitro tool for assessing the efficacy of chelating agents on mobilizing accumulated Hg from renal tissue.

Thesis (M.Sc.)(Hons) -- University of Western Sydney, 2005. / "A thesis presented to the University of Western Sydney in fulfilment of the requirements for the degree of Master of Science (Honours) Physics" Bibliography: leaves 101-108.

Atmospheric haze, which builds up over South Africa including our study areas, Cape Town and the Mpumalanga Highveld under calm weather conditions, causes public concern. The scope of this study was to determine the concentration and composition of atmospheric aerosol at Khayelitsha (an urban site in the Western Cape) and Ferrobank (an industrial site in Witbank, Mpumalanga). Particulate matter was collected in Khayelitsha from 18 May 2007 to 20 July 2007 (i.e. 20 samples) using a Partisol-plus sampler and a Tapered Element Oscillating Microbalance (TEOM) sampler. Sampling took place at Ferrobank from 07 February 2008 to 11 March 2008 (6 samples) using a Partisol-plus sampler and an E-sampler. The gravimetric mass of each exposed sample was determined from pre- and post-sampling weighing. The elemental composition of the particulate matter was determined for 16 elements at Khayelitsha using Proton Induced X-ray Emission (PIXE). The concentration of the elements Al, Si, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Cu, Zn, As, Br, Sn, and Pb was determined by analysing the PIXE spectra obtained. In similar manner, the elemental composition of the particulate matter was determined for 15 elements at Ferrobank (Al, Si, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Cu, Zn, As, Br and Pb). The average aerosol mass concentrations for different days at the Khayelitsha site were found to vary between 8.5 μg/m3 and 124.38 μg/m3. At the Khayelitsha site on three occasions during the sampling campaign the average aerosol mass concentrations exceeded the current South African air quality standard of 75 μg/m3 over 24 h. At the Ferrobank site, there are no single days that exceeded the limit of the South African air quality standard during the sampling campaign. Enrichment factors for each element of the particles sampled with an aerodynamic diameter of less than 10 μm (PM10) samples have been calculated in order to identify their possible sources. The analysis yielded five potential sources of PM10 : soil dust, sea salt, gasoline emissions, domestic wood and coal combustion. Interestingly, enrichment factor values for the Khayelitsha samples show that sea salt constitutes a major source of emissions, while Ferrobank samples, the source apportionment by unique ratios (SPUR) indicate soil dust and coal emission are the major sources of pollution. The source apportionment at Khayelitsha shows that sea salt and biomass burning are major source of air pollution.

This master’s thesis is focused on the LIBS technique for compositional differentiation and relative hardness quantification of selected geological samples. The experimental part of this thesis was conducted at the National Institute of Laser Enhanced Sciences (NILES) in Cairo, Egypt where a simple LIBS system was constructed. In parallel to the experimental work, the literature review was surveyed with the aim to give a thorough view of the history, fundamentals and all the factors related to LIBS. LIBS is a developing analytical technique, which is used to perform qualitative and semi-quantitative elemental analysis of materials (solid, liquid and gas). The fast data collection and the lack of sample preparation made LIBS be an attractive technique to be used for geological samples. This study was done to improve analytical methods for geochemical analysis of samples during different exploration phases (Mining, filed analysis, etc.), as a real-time analysis method to save money and time spent in labs. For a generation of laser induced plasma, a Q-switched Nd: YAG laser operated at 10 Hz and wavelength of 1064 nm was employed on the surface of the samples. A spectrometer fitted with an intensified charge-coupled device (ICCD) was used to disperse and detect the spectrum; then fed to a computer for recording and further processing of the data. The sample set was compiled from samples collected from different areas (South Africa and Namibia). Using principal component analysis (PCA), it was found that LIBS was able to differentiate between the samples even those of the same area. The results from the LIBS technique were correlated with subsequent analysis of the same samples by Particle-induced X-ray emission (PIXE). The feasibility of relative hardness estimation using LIBS was done by measuring the plasma excitation temperature for different samples. LIBS with its advantages as an elemental analysis technique made it possible to estimate the hardness of geological samples. Based on theory and results, an analytical technique for compositional differentiation and quantification of relative hardness of geological samples is proposed. / National Research Foundation (South Africa) / Physics / M Sc. (Physics)