Quantitative multielemental analysis using Particle Induced X-ray Emission (PIXE) using 1 and 2 MeV proton bombardment on thin targets has been achieved. The method is based on the calculation of atomic ratios from experimentally determined relative x-ray efficiency curves. Sample preparation techniques involving digestion and homogenous deposition of samples and standards with a minimum of contamination have been investigated. The accuracy of the method has been evaluated using five standard reference materials obtained from the National Bureau of Standards. The elimination of bremsstrahlung associated with the charging effect of non-conducting samples in PIXE analysis has been accomplished using thin carbon foils in the beam path. Applications of the PIXE technique to studies on deep-sea ferromanganese nodules were performed. The utility of PIXE in the analysis of noduoles and in the following of the distribution of a large number of elements through the various stages of a processing scheme were demonstrated.

No description available.

The phosphine(III) crown ethers, [4'-(N-phenylaza-15crown-5)]3P (1), [4'-(N-phenylaza-l8-crown-6)]3P (2), [4'-(Naza-18-crown-6)]2-Ph-P (3), and [4'-(benzo-15-crown-5)]3P (4) were synthesized by using an electrophilic bromination of the crown phenyl ring (with a tribromide ion) followed by the preparation of a lithium salt and subsequent reaction of the resulting lithiocrowns with P(III) reagents. The oxide of compound 1 was completely characterized by an X-ray diffraction study, which showed that structurally there is not a significant difference in P-O bond distances and OPC bond angles with [4'-(N-phenylaza-15-crown-5)]-Ph2-P=O. Thespectroscopic data of compound 1 and 2 were compared. It appears that 1 and 2 are similar in P environment; also they are more air sensitive than 3 and 4. In addition, a discussion about compounds 1-4, and a literature review of the preparation of phosphines are included. / Department of Chemistry

Typescript. / Thesis (Ph. D.)--University of Hawaii, 1970. / Bibliography: leaves [76]-79. / vi, 79 l maps, graphs, tables

Typescript. / Thesis (Ph. D.)--University of Hawaii, 1970. / Bibliography: leaves 183-192. / xiii, 192 l illus., graphs, tables

Thesis (Ph. D.)--Virginia Commonwealth University, 2010. / Prepared for: Dept.of Computer Science. Title from resource description page. Includes bibliographical references.

Thesis (Ph.D.)--OGI School of Science & Engineering at OHSU, Mar. 2006. / Includes bibliographical references (leaves 114-140).

Thesis (Ph. D.)--University of Missouri-Columbia, 2005. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (May 23, 2006) Vita. Includes bibliographical references.

Thesis (M.S.)--University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on September 14, 2007) Vita. Includes bibliographical references.

M.Sc. / Aerosol samples were collected at stations using simple filter unit, loaded with a 4 7 mm diameter pore size Nuclepore membrane filter. The sampling duration was 24 hours for each sample, with the total of 11 samples: seven for Thohoyandou and four for Bethlehem. The samples were analyzed with energy dispersive X-ray fluorescence spectrometry for up to 20 elements. Comparison for elemental concentrations of the data showed that the samples fall into three clusters on average (major: Ca, Cl, Si. S, Fe and AI; intermediate: K, Ti, Pb, Brand Zn; minor: Mn, Cr, As, Sr, Ni and Cu), with the samples collected from Bethlehem having high concentrations in all clusters. High concentrations in the samples collected on Bethlehem were attributed to entrainement of dust particles during the dry winter period. The results also show that the elements are associated with anthropogenic emissions. Therefore, the sampling station at Thohoyandou is considered as a background station due to the low aerosol concentration. The aerosol concentration levels at Thohoyandou can be attributed to biogenic sources because of the large presence of large forest areas in the region and in the vicinity of the sampling location. The samples collected in both regions reveal highly enriched sulphur, chlorine, zinc and lead. It is clearly proved that these elements come from local soil. Chromium and copper were both slightly enriched in Thohoyandou, but the concentration data for these two elements are not available. However it is supposed that these elements come from local soil as well. In another aerosol analysis, passive (diffusive) samplers were used to measure concentration levels for sulphur dioxide and nitrogen dioxide. The measurement campaign was carried out from Soweto in Johannesburg and Bohlokong in Bethlehem with the campaign lasting for two months during the w~nter season. A very clear result derived for sulphur dioxide was the dominating source contribution from use of coal for heating and cooking in both areas. For nitrogen dioxide, it was found that contribution from traffic in highly populated areas and from industrial activities in the neighbourhood of the two areas was the source. The role played by wood burning, is also another additional source used for domestic heating and even cooking.