Yucca Mountain, Nevada is the proposed site of a geologic repository for the disposal of spent nuclear fuel and high-level radioactive waste in the United States. In the event repository engineered barriers fail, the saturated alluvium located south of Yucca Mountain is expected to serve as a natural barrier to the migration of radionuclides to the accessible environment. The purpose of this study is to improve the characterization of uranium retardation in the saturated zone at Yucca Mountain to support refinement of an assessment model. The distribution of uranium desorption rates from alluvium obtained from Nye County bore holes EWDP-19IM1, EWDP-10SA, EWDP-22SA were studied to address inconsistencies between results from batch sorption and column transport experiments. The alluvium and groundwater were characterized to better understand the underlying mechanisms of the observed behavior. Desorption rate constants were obtained using an activity based mass balance equation and column desorption experiments were analyzed using a mathematical model utilizing multiple sorption sites with different first-order forward and reverse reaction rates. The uranium desorption rate constants decreased over time, suggesting that the alluvium has multiple types of active sorption sites with different affinities for uranium. While a significant fraction of the initially sorbed uranium desorbed …

This dissertation is organized in an alternate format. Several manuscripts which have already been published or are to be submitted for publication have been included as separate chapters. Chapter 1 is a general introduction which describes the dissertation organization and introduces the human bone and ceramic materials as bone substitute. Chapter 2 is the background and literature review on dissolution behavior of calcium phosphate, and discussion of motivation for this research. Chapter 3 is a manuscript entitled ''Si,Zn-modified tricalcium phosphate: a phase composition and crystal structure study'', which was published in ''Key Engineering Materials'' [1]. Chapter 4 gives more crystal structure details by neutron powder diffraction, which identifies the position for Si and Zn substitution and explains the stabilization mechanism of the structure. A manuscript entitled ''Crystal structure analysis of Si, Zn-modified Tricalcium phosphate by Neutron Powder Diffraction'' will be submitted to Biomaterials [2]. Chapter 5 is a manuscript, entitled ''Dissolution behavior and cytotoxicity test of Si, Zn-modified tricalcium phosphate'', which is to be submitted to Biomaterials [3]. This paper discusses the additives effect on the dissolution behavior of TCP, and cytotoxicity test result is also included. Chapter 6 is the study of hydrolysis process of {alpha}-tricalcium phosphate in the …

In a time of laissez-faire government, monopolistic businesses and political debauchery, William Andrews Clark played a significant role in the developing West, achieving financial success rivaling Jay Gould, George Hearst, Andrew Carnegie, and J. P. Morgan. Clark built railroads, ranches, factories, utilities, and developed timber and water resources, and was internationally known as a capitalist, philanthropist and art collector. Nonetheless, Clark is unjustly remembered for his bitter twelve-year political battle with copper baron Marcus Daly that culminated in a scandalous senatorial election in January 1899. The subsequent investigation was a judicial travesty based on personal hatred and illicit tactics. Clark's political career had national implications and lasting consequences. His enemies shaped his legacy, and for one hundred years historians have unquestioningly accepted it.

The effects of cranial electrotherapy stimulation (CES) on human EEG and brain current density were evaluated by quantitative electroencephalography (qEEG) and low resolution brain electromagnetic tomography (LORETA). A total of 72 research subjects were provided with a single session of CES, 38 were provided with 0.5 Hz CES while 34 were provided with 100 Hz CES. The qEEG paired t-tests revealed that in both frequencies of CES there was a significant (.05) increase in alpha relative power with concomitant decreases in delta and beta relative power. The 0.5 Hz CES decreased a wider frequency range of delta activity, while the 100 Hz CES decreased a wider frequency range of beta activity; suggesting some difference may exist in the EEG response to different frequencies of CES. The changes found in qEEG relative power were consistent with the affective and cognitive effects of CES reported in the literature, such as increased relaxation and decreased anxiety. Statistically significant changes for qEEG values other than relative power, such as coherence, amplitude asymmetry, phase lag and power ratios were also found. The LORETA paired t-tests found statistically significant (.05) increases in cortical and subcortical theta and alpha frequency current density with concomitant decreases in delta …