Physical Sciences and Mathematics Commons^™

Air-Water Gas Exchange And The Carbon Cycle Of Green Bay, Lake Michigan, James Waples

Theses and Dissertations

The purpose of this study was to constrain estimates of the kinetics of gas transfer across the air-water interface as well as quantify the net flux of carbon between southern Green Bay (1635 km²) and the atmosphere.

In 1994 and 1995, over 3500 measurements of surface water CH₄ and CO₂ were made using a continuous sample disk equilibrator. Estimates of CH₄ flux from southern Green Bay to the atmosphere based on air-water concentration gradients, shear corrected wind speeds and the U/K (wind speed/transfer coefficient) relationship of Broecker et al. (1978) agreed to within ~10% of …

Effects Of Physical And Chemical Properties Of Bright And Dull Coal Lithotypes On The Formation Of Char Particles, Chad G. Tomforde

Theses and Dissertations

The Energy and Environmental Research Center is working with EPRI and a consortium of companies in partnership with DOE to determine factors causing sticky ash to blind or bridge hot-gas cleanup filters. In this study, bright and dull lithotypes were separated from bituminous, subbituminous and lignitic coals to determine physical and chemical properties that may lead to the formation of different charforms, and consequently, fine and sticky ash that is problematic in coal-fired combustion systems.

Proximate and ultimate, maceral, and energy dispersive X-ray fluorescence (EDXRF) analyses were used to characterize each lithotype. A bench-scale pressurized fluidized-bed reactor (PFBR) was used …

Determining Capture Zones For Three-Dimensional, Heterogeneous, Anisotropic Aquifers By Monte Carlo Analysis, Jon Paul Jones

Theses and Dissertations

Most methods of delineating capture zones for pump-and-treat remedial design and wellhead protection assume a two-dimensional, homogeneous aquifer. Aquifers, however, are three-dimensional and heterogeneous, thereby introducing uncertainty in capture zone analysis. This study used a Monte Carlo analysis of three sets of statistical parameters defining aquifer heterogeneity. Each set had a different variance for the mean natural log hydraulic conductivity, which varied among the sets by a factor of four. The ensemble means of the capture zones for each set were estimated from 10 randomly generated fields with 12 layers each which were superimposed on each other for a total …

Paleosols As Holocene Proxy Climate Indicators, Mclean County, North Dakota, Deborah L. Beck

Theses and Dissertations

An exposure with 15 buried A-horizons near Douglas Creek, Lake Sakakawea, central North Dakota, has provided an excellent opportunity for paleoclimate reconstruction. Analyses included texture, stable carbon, radiocarbon, pollen, and phytoliths. The variations in these properties between individual soil horizons served to reconstruct the former environments of each soil horizon.

The paleosols were developed in a sequence of deposits in a mile-long tributary to the Missouri River. The soils are in a shallow valley fill exposed by wave action along the north shore of Lake Sakakawea. The 1996 exposure was up to 4m high and 51.5m wide. There were up …

A Methodology For Studying Denitrification By Recently Formed Sulfides, Bethany A. Bolles

Theses and Dissertations

Nitrate (N03) contamination due to anthropogenic sources is a serious and widespread health problem. In many groundwater systems, N03-can be reduced to a harmless gas, N2, through the bacterially mediated process of denitrification. During this process, bacteria gain energy by transferring electrons from an "electron donor" to nitrate, the "electron acceptor". It is typically believed that organic carbon is the most important electron donor in the denitrification process; however, increasing amounts of research suggest the importance of inorganic electron donors. The most extensive studies involving the reduction ofN03- by inorganic species have focused on pyrite (FeS2) and Fe(II). Few studies …