Physical Sciences and Mathematics Commons^™

Estimating Permeability From The Grain-Size Distributions Of Natural Sediment, Lawrence Mastera

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Permeability, k, can be estimated using the Kozeny-Carman equation, given a grain-size distribution with any number of grain-size categories and the porosity of a sediment. A recursive method was developed to calculate the effective grain-size parameter, d, for sediment mixtures with more than three grain sizes. The method was tested on four sediment models of sand, gravelly sand, sandy gravel, and open-framework gravel created from grain-size distributions. The k estimated from the recursive method were consistent with physical measurements of k.

Dimethylmercury Production In Freshwater Sediments, David C. Kelly

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Dimethylmercury (DMHg) has been examined almost exclusively in marine environments to date, plays an uncertain role in the global cycling of Hg, and is produced by a currently unknown mechanism in natural systems. We examined DMHg production in microcosms containing 100 cm3 of freshwater sediment sampled from 3 wetlands and a lake near Dayton, Ohio. DMHg was produced from all sediments analyzed, and found that production is increased significantly by the addition of inorganic Hg from ~0.1pM to ~10pM, its production is unaffected by autoclaving the sediment, and organic carbon additions had no discernible effect on production. Its total concentrations …

Transport Through Georeservoirs: Spatial Entropy In Hydraulic Properties, And Temporal Entropy In Residence Time Distributions, Lumeng Huang

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The general principle of maximum entropy can be used to guide the construction of flow and transport models parameters when are uncertain. The principle states that the model which maximizes the entropy should be chosen so that the full multiplicity or uncertainty is represented in the model outcomes.

In models for flow and transport through georeservoirs, the principle would commonly be applicable to the uncertainty in the model outcome for the time of travel through the system, in order to represent the full range of multiplicity in the distribution of residence times. Importantly, the model which maximizes the entropy in …

How The Growth Of The Frampton Fold Affected The Growth Of The Green Knoll Diapir, John A. Zinck

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The growth of structural features formed by the movement of the Louann Salt within the study area follows a fold-first model (Rowan et al., 2000), in which the formation of the Frampton Fold predates the formation of the Green Knoll Diapir. The Frampton Fold was formed during two growth episodes driven by movement of the Louann Salt within the study area. The folding and faulting resulting from these growth episodes created a conduit through which the autochthonous Louann Salt was extruded to the sea floor during the Pliocene. Following a depositional episode consisting of the early sequences of the Mississippi …

Reservoir Analysis Of The Clinton Interval In Stark And Summit Counties, Ohio, Dominick Andrew Wytovich

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The characteristics of a sandstone reservoir of Silurian age (the "Clinton interval") were analyzed using 382 geophysical well logs from the Dominion Gas storage field located in Stark and Summit Counties, Ohio. These sandstones have long been identified by the informal drillers' terms, White, Red, and Stray Clinton. Gamma ray logs were used to analyze the distribution of net stand thickness and its relation to initial production through the construction of isopach and net sand isolith maps. I constructed eight cross sections to identify and correlate the tops of three prominent sandstones and two marine flooding surfaces to evaluate reservoir …

Functional Identification Of Microorganisms That Transform Mercury In Marine Sediments, Lisa Romas

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Monomethylmercury (MMHg) is the toxic form of mercury (Hg) that biomagnifies in food webs, and human exposure to MMHg occurs predominantly via consumption of fish. The primary source of MMHg to the marine environment is thought to be in situ sedimentary production by benthic microorganisms, namely sulfate-reducing bacteria (SRB). I collected sediments from the continental shelf (stations 2 and 6) and slope (station 9) of the NW Atlantic Ocean, and amended them with various inhibitor and promoter solutions to target specific functional groups capable of Hg transformations. I also added stable enriched Hg isotopes to quantify gross Hg methylation and …

Mercury Speciation In Temperate Tree Foliage, Melissa Danielle Tabatchnick

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Cycling of mercury (Hg) and monomethylmercury (MMHg) in forest ecosystems can affect exposures of terrestrial and aquatic wildlife within the watershed. Litterfall has been posited to be a major source of MMHg and total Hg to the forest floor; however, the origin of MMHg associated with tree foliage is largely unknown. I tested the hypothesis that leaf MMHg would be controlled by root uptake and thereby proportional to levels in soil. Fresh leaves and associated soil samples were sampled from nine tree species (deciduous and coniferous) at 30 locations spanning a 1145 km2 area in southwest Ohio, a region presumed …

Trace Metal Fluxes In Southwest Ohio Watersheds, Avani Naik

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Land-use and watershed characteristics affect the cycling and transport of trace metals in rivers. I investigated the influence of different land uses and water physicochemistry on loadings, partitioning, and speciation of Hg, Zn, Cr, Ni, V, Cd, Cu, and Pb in three contrasting watersheds near the Dayton, Ohio metropolitan area over a 13-month period; Wolf Creek (urban/residential), Holes Creek (urban/residential), and Little Miami River (agricultural). Metal concentrations were related positively to discharge in each stream. Dissolved organic ligands appear to influence trace-metal partitioning between filtered and particle phases, however, particle-associated metals were dominant in each site. Total Hg concentrations and …

Conversion Of Carbon Dioxide And Hydrogen Into Methane In Bench-Scale Microcosms And Packed Column Reactors, Brian Alexander Congiu

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Escalating energy demands, rising costs, and increasing awareness of the environmental impacts of current energy sources have created an immediate need for sustainable, alternative energy resources and innovative fuel technologies. It is believed that a potential carbon-neutral fuel source can be generated through the microbial production of methane gas by methanogenic archaea. Carbon dioxide captured from the atmosphere and renewable production of hydrogen can be used to support these microorganisms for the large-scale production of methane. Bench-scale investigations involving 160 mL serum bottle batch experiments and two 11L packed-column reactors were conducted to evaluate the feasibility and efficiency of microbial …