Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2006. / Edward Hoffman, Committee Member ; Nolan Hertel, Committee Member ; Weston Stacey, Committee Chair.

The groundwater travel time along the fastest path of likely radionuclide transport is a regulatory criterion used to assess the hydrogeologic quality of a high - level radioactive waste repository. Hydrologists and engineers are limited in their ability to define with confidence the fastest path, owing to the heterogeneous nature of geologic materials. Field measurements of hydraulic properties such as in test or observation wells, are inherently averages of properties at scales smaller than the scale of the field measurement. As a result of averaging, subscale information is lost and there is uncertainty in defining the fastest trajectory of groundwater. This scale problem is explained through a review of the continuum and REV concepts in groundwater hydrology. The application of hydrodynamic dispersion concepts is recommended as a means of incorporating the effect of subscale heterogeneity on the fastest groundwater travel time. Sources of uncertainties in predicting groundwater travel time are discussed in the report. The uncertainties are mainly attributed to the heterogeneous nature of geologic formations. The heterogeneity of geologic materials can, however, be characterized quantitatively using geostatistical methods. Important statistical parameters include mean and variance. as well as the spatial correlation structures of the hydrologic properties within the hydrogeologic system. These parameters may he obtained from limited data base. Stochastic methods, reviewed and explained in this report, can take advantage of the geostatistical characterization to predict large -scale groundwater flow and solute transport. Several examples from recent scientific literature are provided to illustrate the application of stochastic methods to the groundwater travel time analysis. Stochastic methods in subsurface hydrology have only recently been evaluated under field conditions for a few locations, and validation of the theories is incomplete, especially in unsaturated fractured rocks. Nevertheless, research efforts should continue to improve the state -of -the art. Geostatistics and stochastic methods will be valuable tools in addressing the groundwater travel time objective

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The microwave induced plasma was used to sinter synthetic Idaho Chemical Processing Plant (ICPP) alumina and zirconia based high level nuclear waste calcines in a nitrogen atmosphere. The sintering behavior of these nuclear waste calcines was observed with identification of the phases formed. A sintered density of higher than 3.20 g/cm3 was obtained within 10 minutes of plasma sintering of pure calcines. The addition of frit in pure calcines to form glass-ceramics resulted in a decrease of density to less than 2.0 g/cm3. This was attributed to the reaction between frit and volatile substances in both zirconia based and alumina based calcines. The removal of volatile substances before sintering increased the sintered density of calcines. The lower sintered density was obtained for the more volatile samples. The phases formed in the plasma sintering of calcines were identified as a function of temperature and amount of frit.

Cometabolic biodegradation processes are potentially useful for the bioremediation of hazardous waste sites. In this study the potential application of phenol-oxidizing and nitrifying bacteria as "priming biocatalysts" was examined in the degradation of polycyclic aromatic hydrocarbons (PAHs), aryl ethers, and aromatic ethers. We observed that a phenol-oxidizing Pseudomonas strain cometabolically degrades a range of 2- and 3-ringed PAHs. A sequencing batch reactor (SBR) was used to overcome the competitive effects between two substrates and the SBR was evaluated as a alternative technology to treat mixed contaminants including phenol and PAHs. We also have demonstrated that the nitrifying bacterium Nitrosomonas europaea can cometabolically degrade a wide range polycyclic aromatic hydrocarbons (PAHs), aryl ethers and aromatic ethers including naphthalene, acenaphthene, diphenyl ether, dibenzofuran, dibenzo-p-dioxin, and anisole. Our results indicated that all the compounds are transformed by N. europaea and that several unusual reactions are involved in these reactions. In the case of naphthalene oxidation, N. europaea generated predominantly 2-naphthol whereas other monooxygenases generate 1-naphthol as the major product. In the case of dibenzofuran oxidation, 3-hydroxydibenzofuran initially accumulated in the reaction medium and was then further transformed to 3-hydroxy nitrodibenzofuran in a pH- and nitrite-dependent abiotic reaction. A similar abiotic transformation reaction also was observed with other hydroxylated aryl ethers and PAHs. We also characterized the role of AMO in the degradation of aromatic ethers. Our results indicated that aromatic ethers including anisole were transformed by both 0-dealkylation or hydroxylation reactions. This research has led to the development of a rapid colorimetric assay to detect AMO activity. / Graduation date: 1998

Thesis (M.S.)--Middle East Technical University, 2003. / Keywords: Cleaner production, waste reduction, dairy, market milk processing.

Thesis (Ph. D.)--University of Oregon, 2000. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 169-178). Also available for download via the World Wide Web; free to University of Oregon users.

Thesis (M.S.)--Mississippi State University. Department of Agricultural and Biological Engineering. / Title from title screen. Includes bibliographical references.

Thesis (Ph. D.)--University of Alberta, 2009. / Title from PDF file main screen (viewed on Feb. 19, 2010). A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy, Department of Civil and Environmental Engineering, University of Alberta. Includes bibliographical references.

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