This study investigates the extraction of hydrocarbons from oil sand using supercritical carbon dioxide (SC CO2). Experiments were carried out on three different types of oil sands. After some preliminary experiments, the feasibility of extracting hydrocarbons from oil sands by SC CO2 was confirmed and three experimental factors (pressure, temperature and mixing rate) were identified for further study. A two to the three factorial design was used to determine the significance of each factor and the significance of the interaction of the factors on the extraction efficiency. The extraction efficiency was calculated from Dean-Stark extraction analysis and was compared to the extraction efficiency based on gravimetric analysis. The results show that the extraction efficiency increased with pressure at a constant temperature. The effect of temperature on extraction efficiency is complex. The highest extraction efficiency was obtained at the high pressure (24.1MPa), high temperature (60C) and a mixing rate of 250rpm. / Environmental Science

Graduation date: 1998

The use of Digital Image Correlation (DIC) technique has become increasingly popular for displacement measurements and for characterizing localized material deformation. In this study, a three-dimensional digital image correlation analysis (3D-DIC) was performed to investigate the displacements on the surface of isotropically consolidated and drained sand specimens during triaxial compression tests. The deformation of a representative volume of the material captured by 3D-DIC is used for the estimation of the kinematic and volumetric conditions of the specimen at different stages of deformation, combined with the readings of the global axial compression of the specimen. This allowed for the characterization of a Mohr-Coulomb plasticity model with hardening and softening laws. In addition, a two-dimensional axisymmetric finite element model was built to simulate the actual experimental conditions, including both the global and local kinematics effects captured by 3D digital image correlation analysis on the boundary of the specimen. A comparison between the axisymmetic model predictions and the experimental observations showed good agreement, for both the global and local behavior, in the case of different sand specimen configuration, including loose, dense and half-loose half-dense specimens.

Typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1976. / Bibliography: leaves 404-427. / Microfiche. / vi, 427 leaves

The effects of differential irrigation treatments on the water use of broccoli (c.v. Indurance) and carrots (c.v. Stefano) were studied in the rainy, winter season from July to September 2006 and in the dry, summer period from November 2006 to March 2007, respectively. Broccoli and carrots are produced on the Swan Coastal Plain region on Grey Phase Karrakatta Sand. Such soils generally have water holding capacities as low as 10 to 13%. This soil is typical to the Swan Coastal Plain and requires irrigation to be applied at rates of up to 150% of class A pan evaporation (Epan) to optimise growth and quality. / High spatial uniformity (an average of 90%) of water distribution (DU) was achieved with the sprinkler irrigation system. The average irrigation water use efficiencies (Eu) in both the experiments were relatively high, at 78% and 95% in broccoli and carrot trials, respectively. The numerous rainy days during the winter season affected the results of water application efficiencies (Ea) of the broccoli experiment, which ranged from 35% to 43%. This contrasted with the carrot experiment where the water application efficiencies (Ea) of the 100% Epan and Crop Factor (CF) treatments were 81% and 78%, respectively. For the carrot experiment the water application efficiencies for the 100% Epan and crop factor treatments were 14% higher than the 150% Epan treatment. These results indicate that the sprinkler irrigation systems in both experiments showed good performance makes the system suitable for experimental purposes and also for vegetable production on soils of this nature. / Despite the differences in irrigation volume, soil water contents remained very high and did not differ among treatments in both the experiments. The differential soil water stress index (DSWSI) for the 100% Epan (T1) and variable water replacement (VR) (TVR) treatments ranged from 0.74 to 1.71 for both broccoli and carrot trials. There were only small soil water tension differences among all the irrigation treatments and ranged from -2.4 kPa to -7.6 kPa, which was within the range between saturation and field capacity for sandy soil (0 to -10 kPa). / In the broccoli experiment, even though the 150% Epan (T2) irrigation treatment received 46% and 61% more irrigation than the 100% Epan (T1) and variable water replacement (TVR) irrigation treatments respectively, the treatments appeared to be largely negated by the high incidence of rainfall during the growing season. For example, the total depth of water application at 150% Epan was 13.9% and 17.2% greater than 100% Epan and TVR treatments respectively. As such the yield, biomass components and nutritional value (ascorbic acid and carotenoid content) did not vary among the treatments. However, irrigation was still required based on the set scheduling parameters and when considered in isolation of rainfall the irrigation crop water use efficiency (WUEi) on T1 and TVR treatments increased by 1.6-fold compared to T2 treatment. / For the carrot experiment the total depth of water application (rainfall and irrigation) for the 150% Epan treatment was 33% and 23% greater than at 100% Epan and Crop factor (CF) treatments, respectively. The yield (carrot roots) on a fresh weight basis (FW) for plants irrigated with the 150% of Epan and Crop factor (CF) treatments were 16% and 20% higher than the yield for plants irrigated with the 100% Epan treatment. Total (root and shoot) fresh weight of carrot plants irrigated For the carrot experiment the total depth of water application (rainfall and irrigation) for the 150% Epan treatment was 33% and 23% greater than at 100% Epan and Crop factor (CF) treatments, respectively. The yield (carrot roots) on a fresh weight basis (FW) for plants irrigated with the 150% of Epan and Crop factor (CF) treatments were 16% and 20% higher than the yield for plants irrigated with the 100% Epan treatment. Total (root and shoot) fresh weight of carrot plants irrigated with the CF treatment was 17% higher than the total fresh weight of plants irrigated with the 100% Epan treatment. However, there were no significant differences between irrigation treatments for root and total (root and shoot) mass on a dry weight basis and the ratio of carrot root to shoot, on a fresh and dry weight basis. The root lengths for plants grown with the CF and 150% Epan irrigation treatments averaged 30 cm, and were 14% larger than the root lengths for the 100% Epan treatment. The plant height for plants grown with the CF irrigation treatment was 6% higher than at the 100% Epan irrigation treatment and leaf length at the CF irrigation treatment was 12% greater than at the 150% Epan irrigation treatment. The root diameter and leaf width of carrots were not significantly different for all treatments. There were no significant differences in ascorbic acid and total carotenoid content of carrot roots among the three irrigation treatments. The average values of antioxidant content from diphenylpicrylhydrazyl (DPPH) scavenging, ARP (anti radical power) and total trolox equivalent antioxidant capacity were 44.83%, 0.8789 and 1.056μmol TE/g, respectively. The reduction of the irrigation level treatment from the 150% Epan water replacement to the 100% Epan water replacement increased the percentage of the DPPH scavenging by 1.55%, and total antioxidant capacity (AOC) and ARP activities by 4.19%. / On a dry weight basis, the crop water use efficiencies (WUE) (irrigation plus rain water) of carrot plants irrigated with the 100% Epan and CF treatments, were the same (0.013 g/mm). However, these were 30% greater than the WUE values of carrots irrigated with the 150% Epan treatment. On a fresh weight basis, the WUE of carrot plants irrigated with the 100% Epan and CF (0.120 and 0.132 g/mm) treatments were 14% and 26% greater than the WUE of carrot plants irrigated with the 150% Epan treatment, respectively. / An example of the diurnal trends of the carrot’s physiological responses to the irrigation treatments showed that on average, the rate of photosynthesis, stomatal conductance and intercellular CO2 for carrot plants grown with the 150% Epan treatment was higher than the rate of photosynthesis, stomatal conductance and intercellular CO2 at both the 100% Epan and CF treatments. However, not all the physiology measurements showed a significant difference among all the treatments. The variation in the physiological measurements was predominantly influenced by the change of temperature during the diurnal hours. / This study has proven the hypothesis that, on a free draining sandy soil, the irrigation treatments did not affect the growth and yield. However, there was a potential to reduce irrigation volumes from standard industry levels to maximise the WUE without decreasing the yield and crop quality, especially for broccoli and carrot, in Western Australia.

[Truncated abstract] The axial performance of piles in sand remains an area of great uncertainty in geotechnical engineering. Over the years, database studies have shown that the existing method for offshore piles (e.g. API 2000) is unreliable. There is therefore a clear need for an improved predictive method, which incorporates the state-ofthe- art understanding of the underlying controlling mechanisms. This Thesis is dedicated to address the factors influencing the end bearing performance of displacement piles in siliceous sand with a view to proposing and justifying an improved design formulation. Firstly, a database of displacement pile load tests in sand with CPT data was compiled in collaboration with James Schneider (Schneider 2007). It features the widest database with also the latest available pile load test data (e.g. Euripides, Ras Tanajib, Drammen etc) in electronic form. Evaluation of the three new CPTbased methods (Fugro-05, ICP-05 & NGI-05) against this database has revealed a broadly similar predictive performance despite their end bearing formulations being remarkably different. This anomaly promoted the author to extend the database to include additional tests with base capacity measurements to form new base capacity databases for driven and jacked piles, which resulted in the UWA- 05 method for end bearing of displacement piles in sand. This method accounts for the pile effective area ratio, differentiates between driven and jacked piles, and employs a rational qc averaging technique. ... Field tests were performed in Shenton Park, Perth to supplement the database study and, in particular, to examine the effect of the incremental filling ratio (IFR). 10 open-ended and 2 closed-ended piles were tested in compression followed by tension. The test results provide strong support for the UWA-05 method for base capacity evaluation employing the CPT qc values and the effective area ratio. A series of jacked pile tests was carried out on the UWA beam centrifuge, to further explore the factors affecting pile base response. In total, four uniform and four layered centrifuge samples were prepared and tested at various stress levels and relative densities using three separate pile diameters. The resistance ratio (qb0.1/qc,avg) is found to be independent of the absolute pile diameter, effective stress and soil relative density. The tests in layered soil enabled quantification of the reduction in penetration resistance when a pile/cone approaches a weak layer and revealed the significant influence on base stiffness of underlying soft clay layers. The stiffness decay curves (G/GIN vs. w/D, where GIN is initial operational shear stiffness) measured in static load tests were found to vary with ratios of GIN/qc, while there was a unique relationship between G/GIN and qb/qc. A detailed parametric study was carried out (using the FE code PLAXIS) by idealising pile penetration using a spherical cavity expansion analogue in layered soil. The numerical predictions compare well with the centrifuge results and their generalization enabled guidelines to be established for end bearing in layered soil.

Thesis (Ph. D.)--Utrecht University, 2007. / Vita. Includes bibliographical references (p. 197-209).

Thesis (Ph.D.) -- McMaster University, 1998. / Includes bibliographical references (leaves 236-247). Also available via World Wide Web.

Thesis (M. A. in English)--Vanderbilt University, Aug. 2008. / Title from title screen. Includes bibliographical references.

Thesis (Ph.D.)--University of Western Australia, 2007.