This study utilized individual and county-level analysis to examine the impact of demographic and distal factors on individual level mortality as well as spatial and county specific attributes on county death rates. The data used in the individual level analyses come from the linked NHANES NDI data set and the county level data come from multiple sources including spatially referenced sources. Findings suggest that having private or Federal insurance attenuates the mortality discrepancy between racial groups at the individual level and that spatial factors have an impact on county death rates that are not explained by county attributes. These analyses present questions about using common indicators to measure mortality at different levels suggesting that the variables used to understand mortality on the individual level are different from those that should be used to understand mortality at the county level.

Manufactured fine aggregates are a product created when rocks are crushed using a mechanical crusher. With the depletion of sources of natural sands, the usage of manufactured fine aggregates has increased. Manufactured fine aggregates have properties that differ from natural sands; for this reason, the plastic and hardened properties of concrete produced using manufactured fine aggregates differ from the properties of concrete made with natural sands. The main concrete properties affected by the usage of manufactured fine aggregates are skid resistance, workability, and finishability. The aim of this research project was to investigate how manufactured fine aggregates could be used in concrete pavements without causing workability or skid related issues. To improve the workability of concrete made with manufactured fine aggregates, the use of the optimized mixture proportioning method developed by the International Center for Aggregate Research (ICAR) was investigated. Results obtained from this testing were used to make recommendations on how the ICAR method for pavement concrete could be improved The goal of this research was to also develop laboratory tests that could reasonably predict skid performance of concrete pavements made with different types of sand. For this purpose concrete slabs made with different sands were evaluated for friction and texture using a circular texture meter (CTM), a dynamic friction tester (DFT), and a polisher. To ensure that the values obtained at the laboratory related to field performance, test sections constructed with 100% limestone sand and blended sands were evaluated. Laboratory and field test results for skid were used to identify aggregate tests that best correlates with concrete performance. Results show that the micro-Deval test for fine aggregates could be used to predict the polish resistance of concrete laboratory specimen. Results from field testing has shown that if limestone fine aggregates are not blended with siliceous sands, PCC pavements made with limestone sands on truck lanes could experience a large drop in skid resistance within a year of service. Results obtained from laboratory testing showed that blending a small quantity of siliceous sand with limestone sands considerably increased the skid resistance of concrete specimens. / text

The presence of coal tars in the subsurface associated with former manufactured gas plants (MGPs) offers a remediation challenge due to their complex chemical composition, dissolution behaviour and recalcitrant characteristics. A former MGP site in Clearwater Beach, Florida was characterized and bench-scale analyses were conducted to assess the potential for in situ chemical oxidation (ISCO) using persulfate to treat MGP residuals. Completion of a conceptual site model identified a homogeneous, silty sand aquifer, with an average hydraulic conductivity of approximately 2.3x10-3 cm/s and a groundwater flow rate of 2 cm/day in the direction of S20°E. Six source zones, three near the water table and three in the deep aquifer were estimated to have a total volume of 108 m3. A multi-level well transect was installed to monitor concentrations of dissolved compounds and to estimate mass discharge downgradient of the source zones over time. On average, the morphology of the aqueous concentrations remained consistent with time. A total mass discharge across the transect of 94 mg/day was estimated for site-specific compounds. Bench-scale tests were conducted on aquifer sediments and groundwater samples. The aquifer was determined to have a low buffering capacity, low chemical oxygen demand, and low natural oxidant interaction (NOI) with persulfate. Aqueous batch experiments identified the potential for iron (II) activated persulfate to reduce concentrations of BTEX and PAHs below method detection limits (MDLs). Unactivated persulfate was able to reduce BTEX concentrations to below MDLs after 14 days; however, the concentration of PAH compounds remained above MDLs after 14 days. Higher iron doses within the system were shown to be more effective in reducing BTEX and PAH compounds. Column experiments designed to mimic site conditions were used to evaluate the feasibility of persulfate treatment on impacted sediments from the Clearwater site. Two sets of column experiments were conducted: one using unactivated persulfate followed by alkaline activated persulfate; and one using iron (II) activated persulfate. On average, unactivated persulfate was able to reduce BTEX and PAH aqueous effluent concentrations by > 75% and 40%, respectively, after a total dose of 60 g/g soil. Two additional doses of alkaline activated persulfate (total persulfate dose of ~80g/g soil) in these columns were able to further reduce effluent BTEX and PAH concentrations by > 90% and > 75%, respectively. Iron (II) activated persulfate reduced effluent BTEX concentrations by > 70% and PAHs by > 65% after a total dose of 35 g/g soil. Average reductions in mass for BTEX and PAH compounds were approximately of 48% and 26% respectively in the iron (II) activated persulfate columns, and 24% and 10%, respectively in the alkaline activated persulfate columns. The potential for the ability to use in situ chemical oxidation using persulfate for the remediation of MGP residuals in the subsurface is evaluated using field measurements and bench-scale experimentation. The reductions observed in aqueous phase compounds in MGP groundwater as observed in the laboratory indicate the potential for reductions in groundwater concentrations at this and other contaminated former MGP sites. However, column experiments, indicating the inability for activated persulfate to reduce all identified compounds in the MGP NAPL suggest source treatment with activated persulfate would not reduce concentrations to below Florida Department of Environmental Protection natural attenuation concentrations.

Exotic amphibians are often detrimental to native biotas. In Florida, the exotic Cuban Treefrog (Osteopilus septentrionalis) eats native frogs and may outcompete them for resources. Cuban Treefrogs thrive in disturbed areas and around buildings, and often breed in manufactured wetlands such as retention ponds and borrow pits. This study identified limnological, landscape, and biotic characteristics that discouraged pond use by Cuban Treefrogs and promoted use by native amphibian species. I sampled natural and manufactured ponds in Orange County, Florida, for one year, using standard methods to estimate the species richness and relative abundance of amphibians and their potential fish and macroinvertebrate predators. I determined the relationship between the presence of Cuban Treefrogs and twelve limnological (% vegetation, slope, pond age, pH, % dissolved oxygen, air temperature, water temperature, turbidity, conductivity, depth, perimeter, and area) and seven landscape characteristics (% canopy closure over ponds, building density, distance to nearest building, road density, distance to nearest road, distance to nearest forest stand, and % forest cover), plus five biotic factors (native amphibian richness and abundance, fish richness and abundance, and macroinvertebrate abundance). No relationship existed between native amphibian abundance or species richness and the presence or absence of Cuban Treefrogs. Ponds with a greater percentage of vegetation, large perimeters, and low pH and turbidity had greater native amphibian species richness. Cuban Treefrogs were more likely to be found in ponds with a greater percentage of aquatic vegetation and small perimeters. My results show that building large retention ponds containing low-turbidity water will restrict colonization by Cuban Treefrogs and maintain species richness of native amphibians.

Implementations of numerical simulations for solving systems of partial differential equations are often not verified and are falsely assumed to work correctly. As a result, the implementations are prone to coding errors that could degrade the accuracy of the solution. In order to ensure that a code is written correctly, rigorous verification of all parts of the code is necessary. Code verification is the task of ascertaining whether a numerical algorithm is solving the governing equations of the problem correctly. If an exact solution existed for the governing equations then verification would be easier but these solutions are rare because of the non-linearity of common Computational Fluid Dynamics (CFD) problems. In the absence of exact solutions, grid refinement studies are the most commonly used methods to verify codes using simulations on a sequence of grids but even these studies have limitations. The Method of Manufactured Solutions (MMS) is a novel and a recently developed technique that verifies the observed order-ofuracy of the implementation of a numerical algorithm. The method is more general and overcomes many of the limitations of the method of exact solutions and grid refinement studies. The central idea is to modify the governing equations and the boundary conditions by adding forcing functions or source terms in order to drive the discrete solution to a prescribed or ``manufactured' solution chosen a priori. A grid convergence study is performed subsequently to determine the observed orders. Two methods of accuracy assessment are presented here - solution accuracy analysis and residual error analysis. The method based on the error in the spatial residual is computationally less expensive and proved to be a valuable debugging tool. In the present work, the Method of Manufactured Solutions (MMS) is implemented on a compressible flow solver that solves the two-dimensional Euler equations on structured grids and an incompressible code that solves the two-dimensional Navier-Stokes equations on unstructured meshes. Exponential functions are used to ``manufacture' steady solutions to the governing equations. Solution and residual error analyses are presented. The influence of grid non-uniformity on the numerical accuracy is studied.

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This dissertation explores the discursive production of, and response to, environmental disaster. The project is contextualized through the case of the 2010 Deepwater Horizon disaster in the Gulf of Mexico. By interrupting traditional perceptions of environmental disaster, this project frames socio-environmental disasters as a normal and increasingly experienced part of global hydrocarbon capitalism. The project purports that disaster is embedded within the current global economy and the high-]modernist ideologies that underlie it. As such, the strategies and techniques employed to respond to environmental disaster are intimately bound up within the same systemic processes that have created them in the first place. Moreover, because instrumentalist responses are quickly employed to mitigate disaster, the systemic factors productive of disaster remain concealed. Environmental disaster is thus a process of hydrocarbon capitalism rather than a product of it; as such it can, among other categories, be understood as manageable, profitable, and litigable. This research also highlights the normalization of chronic socio-environmental disaster though sensationalistic perspectives on acute disaster. This project explores the potential for resistance through artistic endeavors, highlighting how the discursive processes that construct traditional power/knowledge formations of environmental disaster might be subverted through non-traditional means. While the framework of eco-governmentality is especially useful in highlighting the problematic social relationships to nature, the project nonetheless acknowledges that counter-discourses for are likely to be appropriated by industry for the purpose of new enterprise and profit. / Ph. D.