In this dissertation we use Lie symmetry analysis to obtain invariant solutions for certain soil water equations. These solutions are invariant under two-parameter symmetry groups obtained by the group classification of the governing equation. We also obtain all nontrivial conservation laws for a class of (2+1) nonlinear evolution partial differential equations which are related to the soil water equations. It is shown that nontrivial conservation laws exist for certain classes of equations which admit point symmetries. We note that one cannot invoke Noether's theorem here as there is no Lagrangian for these partial differential equations. / (M.Sc.) North-West University, Mafikeng Campus, 2003

Typescript (photocopy). / Digitized by Kansas Correctional Industries

M. Tech. Engineering Chemical. / Aims to investigate how the addition of impurities in a CO2 stream affects the adsorption capacity of CO2 on South African coals. To achieve this aim, the following objectives were carried out. 1. To measure the adsorption isotherms and adsorption capacities of pure CO2 and flue gas mixtures on various South African coals under in-seam conditions including pressures up to 88 bar and isothermal temperature of 35 &#x00BA%x;C; 2. To evaluate the effects of coal rank on the adsorption isotherms and adsorption capacities of pure CO2 and flue gas mixtures; 3. To do a comparative study to evaluate the effects of CO2 impurities on the adsorption capacity of pure CO2 on coal; 4. To study the degree of preferential sorption of the individual flue gas mixtures components on coal; 5. To determine the suitability of the Langmuir, Freundlich, and Temkin adsorption isotherm models in representing pure CO2 adsorption onto coal; and 6. To determine the suitability of Extended Langmuir (EL) adsorption models in representing the flue gas mixture adsorption onto coal.

Call number: LD2668 .T4 1985 L56 / Master of Science

Call number: LD2668 .T4 1986 K86 / Master of Science / Civil Engineering

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Bibliography: leaves [61-63]. / by Rosalyn A. Preston. / M.S.

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An experimental and numerical modeling investigation was conducted to study interactions between microbial dynamics and transport processes in variably saturated porous media. These interactions are important in a variety of applied problems such as water and wastewater treatment, bioremediation, and oil-field recovery operations. These processes and interactions also have great ecological significance, with global scale implications for carbon cycling in the environment and the related issue of climate change. Experiments were conducted under variably saturated flow conditions in columns and 2D light-transmission chambers packed with translucent quartz sand. A bioluminescent Pseudomonas fluorescens bacterium was utilized in the experiments and bioluminescence was used as a non-destructive measure of bacterial density and distribution. In the column experiments, pressure heads increased (became less negative) at all measured depths, but significant changes in apparent volumetric water contents were only observed in the upper 5 cm of the columns. Permeability was reduced by a factor of 40 within one week during growth on glucose. In the chamber experiments, aqueous-phase saturations decreased by 7-9% in the region of primary colonization and the capillary fringe dropped by 5 cm during the 6-day experiment. The colonized region expanded laterally by 15 cm and upward against the flow by about 7-8 cm. The desaturation phenomenon resulted in increased lateral spreading of solutes around the colonized region. A numerical model was developed and used to help interpret the experimental data. Water flow was modeled using the single-phase Richards equation. Solute and bacterial transport, cell growth, substrate consumption, and gas diffusion were modeled using advection-dispersion-reaction equations. Observed changes in saturations and pressure heads were reproduced approximately using fluid-media scaling to represent an apparent surface-tension lowering effect, which was assumed to be due to sorption of cells and/or biosurfactants at gas-liquid interfaces. Microbial dynamics, and substrate and oxygen consumption were represented using first-order reversible kinetics for cell attachment/detachment, and dual Monod-type kinetics for cell growth and substrate and oxygen consumption. Reasonably good matches were obtained between the observed and simulated results. / Graduation date: 2003

Graduation date: 1994