An optical microscope coupled to a flow cell was used to investigate ice nucleation on five atmospherically relevant mineral dusts at temperatures ranging from 233 to 247 K. Kaolinite and muscovite particles were found to be efficient ice nuclei in the deposition mode, requiring relative humidities with respect to ice (RHi) below 112% in order to initiate ice crystal formation. Quartz and calcite particles, by contrast, were poor ice nuclei, requiring relative humidities close to water saturation before ice crystals would form. Montmorillonite particles were efficient ice nuclei at temperatures below 241 K, but poor ice nuclei at higher temperatures. In several cases, there was a lack of quantitative agreement between these data and previously published work. This can be explained by several factors including mineral source, particle size, observation time and surface area available for nucleation. Heterogeneous nucleation rates (Jhet) were calculated from the onset data. Jhet values ranged from 60 to 1100 cm-²s-¹ for the five minerals studied. These values were then used to calculate contact angles (θ) for each mineral according to classical nucleation theory. The contact angles measured for kaolinite and muscovite ranged from 6 to 12º; for quartz and calcite the contact angles were much higher, ranging from 25 to 27º. The contact angles measured for montmorillonite were less than 15º at temperatures below 241 K, and above 20º at higher temperatures. The reported Jhet and θ values may allow for a more direct comparison between laboratory studies and can be used when modeling ice cloud formation in the atmosphere. The roles of H₂SO₄ and (NH4)₂SO₄ coatings on the ice nucleating properties of kaolinite were also investigated. Onset data was collected for H₂SO₄ coated and (NH4)₂SO₄ coated kaolinite particles at temperatures ranging from 233 to 247 K. In contrast to uncoated kaolinite particles, which were effective ice nuclei, H₂SO₄ coated particles were found to be poor ice nuclei, requiring relative humidities close to water saturation before nucleating ice at all temperatures studied. (NH4)₂SO₄ coated particles were poor ice nuclei at 245 K, but effective ice nuclei at 236 K.

The surface stoichiometry of five samples, two semiconductors (GaAs and InP) and three minerals (galena (PbS), pyrite (FeS2) and sphalerite (Zn, Fe) S), has been determined by a range of surface analysis techniques: ToF-SIMS, XPS, RBS, NRA and PIXE. The strengths and limitations of the five surface and interface analytical techniques have also been assessed by challenging each technique with the above mentioned samples. As a result, a strategy tree for the quantitative surface analysis of real mixed mineral systems has been developed for novice investigators as an operational guide. ToF-SIMS is a technique able to detect species from hydrogen to very complex organic modules with very high sensitivity. SIMS is generally not a quantitative technique due primarily to the matrix effect, i.e. the strong dependence of secondary ion yields on the chemical composition of the sample. However, for well defined systema, quantitative analyses are possible if suitable calibration standards are accessible. / In this study, a preliminary RSF (Relative Sensitivity Factor) study has been conducted on five samples to give RSFs of the major constituents of each sample. XPS is broadly recognised as a surface analysis technique with the ability of determining the elemental composition near the surface region as well as chemical information, but the depth resolution of XPS is poor. RBS is capable of revealing the concentration depth profiles within the sample without destroying the solid surface. RBS is also considered a good quantitative analytical technique. The main disadvantages of RBS are the poor surface sensitivity and the low efficiency in detecting light elements in a high Z substrate. PIXE is a non-destructive multi-element analytical technique based on X-ray spectroscopy and good at detecting medium Z elements (Z~/= 20~30). By using L X-ray lines instead of K X-ray lines, PIXE is also able to detect high Z (>40) elements. However, due to the very low detection efficiency of Si (Li) detectors (typical PIXE detectors) at low X-ray energies, elements lighter than sodium can not be analysed. Another major shortcoming of PIXE is the lack of depth information. Various surface textures of pyrite have been studied in order to investigate the influence of surface conditions on the quantitative results for the individual techniques utilised in this study and the activation induced chemical alteration on pyrite surfaces has also been studied in detail. By comparing the results from these surface analysis techniques, a good understanding of the elemental composition of the mixed minerals has been achieved. / Thesis (PhD)--University of South Australia, 2004.

No description available.

Thesis (Ph.D.) -- McMaster University, 1998. / Includes bibliographical references (leaves 106-120). Also available via World Wide Web.

Thesis (M.S.)--Ohio University, November, 1987. / Title from PDF t.p.

Thesis (B.A.Hons.) from the Dept. of Politics, University of Adelaide. / Typescript (photocopy).

Thesis (B.Sc.(Hons.))--University of Adelaide, Dept. of Economic Geology, 1969. / Two folded maps in pocket on back cover. Includes bibliographical references (4 leaves).

Thesis --University of Adelaide, Faculty of Science. / Typewr. copy.

Thesis (M.A.). / Written for the Dept. of Integrated Studies in Education. Title from title page of PDF (viewed 2008/05/12). Includes bibliographical references.

Thesis (B.S.)--University of Missouri, School of Mines and Metallurgy, 1914. / The entire thesis text is included in file. Typescript. Illustrated by author. Title from title screen of thesis/dissertation PDF file (viewed April 7, 2009) Includes bibliographical references (p. 30).