Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 45-54). Also available on the World Wide Web.

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

The effect of brine ionic composition on oil recovery was studied for a limestone reservoir rock at a high temperature. Contact angle, imbibition, core flood and ion analysis were used to find the brines that improve oil recovery and the associated mechanisms. Contact angle experiments showed that modified seawater containing Mg[superscript 2+] and SO4[superscript 2-] and diluted seawater change aged oil-wet calcite plates to more water-wet conditions. Seawater with Ca[superscript 2+], but without Mg[superscript 2+] or SO₄[superscript 2-] was unsuccessful in changing calcite wettability. Modified seawater containing Mg[superscript 2+] and SO₄[superscript 2-], and diluted seawater spontaneously imbibe into the originally oil-wet limestone cores. Modified seawater containing extra SO₄[superscript 2-] and diluted seawater improve oil recovery from 40% OOIP (for formation brine waterflood) to about 80% OOIP in both secondary and tertiary modes. The residual oil saturation to modified brine injection is approximately 20%. Multi ion exchange and mineral dissolution are responsible for desorption of organic acid groups which lead to more water-wet conditions. Further research is needed for scale-up of these mechanisms from cores to reservoirs. / text

published_or_final_version / Mechanical Engineering / Master / Master of Philosophy

Atlantic salmon (Salmo salar) parr-smolts were exposed to sublethal concentrations of cypermethrin, chlorothalonil, quintozene or atrazine to determine if they affected osmoregulation. After 96 h of exposure to a pesticide, Na+K+-ATPase, hematocrit, liver somatic index (LSI), plasma sodium, chloride, and cortisol concentrations were determined. There were no mortalities observed following a 24-h seawater challenge. No effects were seen with cypermethrin exposure. Chlorothalonil exposure resulted in increases in plasma Na+ concentrations following the seawater challenge in the 0.18 and 3.6 μg/L groups. For quintozene, decreases in LSI was seen at each concentration, and decreases in Na+K+-ATPase activity was seen at 0.55 μg/L as well as a decrease in Na+ concentrations at the highest exposure concentration. Atrazine exposure increased Na+K+-ATPase activity in the 1 and 100 μg/L groups, and plasma cortisol concentrations at100 μg/L. Overall, the pesticides examined had minimal effects on fish osmoregulation and stress at the concentrations tested.

No description available.

A primary goal of this thesis has been to demonstrate that stable, useful measurements of the orientation of the acoustic signal vector as a function of range and time can be obtained from ocean backscatter, and that this orientation, or acoustic phase, can be related to the local sound speed distribution. Such a measurement is quite distinct from the related problem of detecting the rate of phase change, which forms the basis of Doppler technology. Doppler measurements can be made using echoes from a single point, or a sparsely distributed set of targets. Consistent and useful measurement of absolute phase, is inherently more difficult, since it depends upon the positions of individual scatterers, which are normally random and sparse relative to the acoustic wavelength. / Graduate

The collection and analysis of a large number of belemnites and oysters with excellent biostratigraphic and diagenetic control has resulted in a highly detailed determination of the seawater Sr-isotope curve through the Jurassic and Early Cretaceous. The new data confirm the broad trends established by previous work, but the much sharper resolution of the new data allows the application of Sr-isotope stratigraphy with an optimal stratigraphic resolution of ± 1 to 4 ammonite subzones (± 0.5 to 2 Ma). The data show a general decline from the Hettangian (Early Jurassic) to a minimum in the Callovian and Oxfordian (Middle/Late Jurassic). This is followed by an increase through the Kimmeridgian (Late Jurassic) to a plateau reached in the Barremian (Early Cretaceous). In addition, there are major negative excursions in the Pliensbachian/Toarcian (Early Jurassic) and Aptian/Albian (Early Cretaceous). Stable isotope data collected from belemnites and oysters have resulted in the most extensive Jurassic δ¹³C and δ¹⁸O database to date. While both the carbon and oxygen data appear to give reasonable marine signals, the scatter in the data suggests that future research must document possible biological fractionation effects and develop better indicators for the diagenetic alteration of 613C and 6i 8O. The final chapter documents an unexpected correlation between sudden shifts in the Sr-isotope curve, the occurrence of positive 513C excursions, and the eruption of flood basalts. In the Jurassic and Cretaceous there is a correlation in time between sudden downward shifts in the Sr-isotope curve (Pliensbachian, Aptian, Cenomanian/Turonian), the occurance of positive 613C excursions, and the eruption of flood basalts. Each of these major downward shifts in the Sr-isotope curve is followed by a sudden upward shift, which although associated with a positive 613C excursion is not associated with an episode of flood basalt volcanism. In the Cenozoic the Sr-isotope curve no longer displays downward shifts, but the correlation continues between the occurrence of flood basalts and positive 513C excursions. Several lines of evidence suggest that the eruption of flood basalts is associated with pulses of hydrothermal activity, and that this hydrothermal activity brings about the conditions necessary for the genesis of carbon-burial events.

This thesis reports a research of the corrosion mechanism and corrosion rate of steel reinforcement in concrete. Experimental results are presented to compare the corrosion behaviours of steel reinforcement in two blended-cement concretes in seawater. The experimental program included a study of the influence of crack width on macrocell corrosion, an investigation of the procedure for the determination of polarisation curves of steel in concrete and, an evaluation of the corrosion rate of steel in concrete and the influence of crack width as determined by a new polarisation curve analysis. A mechanism is proposed to interpret the different influences, in both the short and long term, of concrete crack width on the macrocell corrosion rate. This mechanism is based on the finding that the corrosion-spread phenomenon is caused by polarisation effects. An oxygen-depletion mechanism is also proposed to explain the much lower macrocell corrosion rate in the slag cement concrete than that in the flyash cement concrete. The procedure for polarisation testing of steel in concrete is found to be critical to obtaining correct polarisation curves. A twotest procedure is verified to be an appropriate procedure and used in this investigation. Experimental polarisation curves of steel in concrete are found to be very different to those expressed by the kinetic Butler-Volmer equation and, this is considered to be a result of the influence of the passive film on the steel surface in concrete. An empirical polarisation formula is developed and its interpretation is based on the postulation of two parallel kinetic processes occurring at the steel/passive-film/concrete interface; one is the active corrosion process and the other is the film growth/dissolution process. The formula is used to model experimental polarisation curves of steel in concrete through curvefitting analyses. Good curve-fitting results are obtained between the polarisation test curves and model curves. The results are used for evaluation of the corrosion rate and Tafel behaviours of steel in the two concretes and for assessment of the influence of crack width on the corrosion rate within the crack zone.