Typescript. / Thesis (Ph. D.)--University of Hawaii, 1969. / Bibliography: leaves [86]-87. / vii, 87 l illus

In this research project gibbsite is taken as a model for understanding and improving dewatering behaviour. The main aim of this study was to investigate primary process variables such as polymer functionality, charge type/density and molecular weight, pH and shear influence interfacial chemistry and particle interactions and the concomitant dewatering behaviour of gibbsite dispersions. In addition the study explored how using these variables, pulp dewaterability might be optimized. / Thesis (MEngineering)--University of South Australia, 2006.

The main aim of this study was to investigate how primary process variables such as clay mineral type, polymer functionality, agitation intensity and temperature influence flocculant-mediated interfacial chemistry and particle interactions and the concomitant dewatering behaviour of colloidally stable clay dispersions. It is also an arching aim to explore how using these variables, pulp detwaterability might be optimised. / Thesis (PhDApSc(MineralsandMaterials))--University of South Australia, 2006.

The broad aim of this research study was to investigate the influence of adsorbing polymers on surface wettability. In particular, the relationship between the properties of the adsorbed polymer layer (the adsorbed amount, layer thickness and morphology) and the surface wettability was elucidated. / Thesis (PhDApSc(MineralsandMaterials))--University of South Australia, 2005.

Thesis (PhD)--University of South Australia, 1997

Monolayer protected nanoparticles (MPNs) display fascinating size-dependent electronic, optical and catalytic properties. They are promising candidates to be used as building blocks with which to construct new generation nanoarchitectures and nanodevices for sensing, electronic and optoelectronic applications. The aggregation and dispersion of colloidal nanoparticles is one of the key issues closely related to their potential applications. Our knowledge of the colloid stability of nanoparticle dispersions with small sizes is still in its infancy, however, thymine is one of the bases in DNA, and is a pH sensitive and chromatic molecule. In the present study, thymine-functionalized self-assembled monolayer protected gold nanoparticles were synthesized. Their morphology and surface structure were characterized using TEM, UV-vis, FTIR, DSC-TGA and XPS techniques. The colloid stability of thymine-capped gold nanoparticle dispersions as a function of the type and concentration of monovalent salt, pH and particle size in alkaline aqueous solution were investigated. The manipulation of colloid stability with light was further explored. The results and conclusions are summarized inthis thesis.

No description available.

Surface spectroscopic techniques have been applied to facets of the flotation beneficiation and hydrometallurgical extraction of sulfide minerals to enhance the fundamental understanding of these industrially important processes. As a precursor to the determination of surface chemical composition, the sub-surface properties of some sulfide minerals that have not previously been fully characterised were also investigated. The electronic properties of ??-NiS and ??-NiS (millerite), Ni3S2 (heazlewoodite), (Ni,Fe)9S8 (pentlandite), CuFe2S3 (cubanite), CuFeS2 (chalcopyrite), Cu5FeS4 (bornite) and CuS (covellite) were investigated by conventional and synchrotron X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy augmented by ab initio density of state calculations and NEXAFS spectral simulations. Particular aspects studied included the relationship between sulfur coordination number and core electron binding energies, the higher than expected core electron binding energies for the sulfur in the metal-excess nickel sulfides, and the formal oxidation states of the Cu and Fe in Cu-Fe sulfides. It was concluded that the binding energy dependence on coordination number was less than previously believed, that Ni-Ni bonding was the most likely explanation for the unusual properties of the Ni sulfides, and that there was no convincing evidence for Cu(II) in sulfides as had been claimed. Most of the NEXAFS spectra simulated by the FEFF8 and WIEN2k ab initio codes agreed well with experimental spectra, and the calculated densities of states were useful in rationalising the observed properties. XPS, static secondary ion mass spectrometry (SIMS) and NEXAFS spectroscopy were used to investigate thiol flotation collector adsorption on several sulfides in order to determine the way in which the collector chemisorbs to the mineral surface, to differentiate monolayer from multilayer coverage, and to characterise the multilayer species. It was found that static SIMS alone was able to differentiate monolayer from multilayer coverage, and together with angle-resolved NEXAFS spectroscopy, was also able to confirm that 2-mercaptobenzothiazole interacted through both its N and exocyclic S atoms. The altered layers formed on chalcopyrite and heazlewoodite during acid leaching were examined primarily by means of threshold S KLL Auger electron spectroscopy, but no evidence for buried interfacial species was obtained.

x, 270 leaves, : ill., tables ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Electrical Engineering, 1975

The DC casting process used for the production of cast aluminium alloy products intended for processing by rolling, extrusion or forging is an economically important process with approximately 10 million tonnes of DC cast product being produced annually world wide [1]. Process productivity, particularly with respect to elimination of casting defects and hence process scrap is an important factor to DC cast product producers. The literature reporting the DC casting process, particularly with respect to the formation of defects on the cast surface, is reviewed and the mechanisms for the formation of such defects examined. A universally understood and accepted explanation was found for only one of the normal surface defects encountered in practice. A number of samples of commercially cast DC products were subject to detailed cast surface examination, particularly surface microstructures. The results of this examination and the literature survey identified molten metal surface tension as a possible contributing factor affecting the molten metal meniscus stability within the DC casting mould. Meniscus instability is linked with the formation of surface defects. The literature on surface tension of aluminium alloys provided only limited information hence the surface tension of a range of binary and ternary alloys, including commercial alloys was determined, producing data hitherto not available. Of the common alloying elements used in commercial aluminium alloys, iron and magnesium were found to significantly reduce the surface tension. Surface fracture also resulted in a reduction in surface tension for the majority of alloys tested. The surface tension data is combined with mould thermal and physical model calculations to propose a mechanism for the formation of the cast surface defects. The model proposes a maximum stable size for the meniscus according to the alloy and mould conditions. Conditions outside these limits result in meniscus instability and the formation of cast surface defects. The model suggests possible operating changes that may reduce the incidence of surface defect formation. The work also identifies a number of areas requiring further investigation before major practical process changes aimed at cast surface defect elimination, may be formulated.