Description of REU Projects for Summer 2001

TITLE: Wetlands and Acid Mine Drainage - Encompasses The Following Titles

Dynamic Ecology in a Disturbed Environment
Does a Natural Wetland Improve Mine Drainage Water Quality
Hydrology of a Wetland Receiving Alkaline Mine Drainage

Natural wetlands may improve mine drainage water quality, however, high flow (wet weather) events must be included and dilution adjustments made. Metal concentrations in vegetation in mine drainage impacted wetlands exhibits significant temporal and spatial variability. Vegetation, macroinvertebrate and fish community structure in mine drainage impacted wetlands exhibit significant temporal and spatial variability. Hydrologic variability in mine drainage impacted wetlands may be substantial and require significant understanding. Top

TITLE: A Study On The Influence Of The Input Parameters On Subsurface Transport And Fate Processes

Abstract: The researcher located digital data from the Borden, Ontario, Canada test site. The project modelled subsurface contaminant transport using the computer codes MODFLOW and MT3DMS. Flow was also studied through porous media and subsurface contaminant transport. Top

TITLE: Interpretation of In-Situ Tests for Unsaturated Soils

Abstract: This project involved geotechnical engineering research with a calibration chamber designed for unsaturated soils. Specifically, unsaturated soil beds were prepared, including mixing and compaction; the chamber was assembled; instrumentation was installed ; the soil beds were stressed to achieve the desired state of total stress and matric suction while the soil bed deformations were monitored; and pressuremeter tests were conducted in the soil bed following equilibrium. One of the most significant accomplishments of this work was the development of a spreadsheet macro to iteratively back-calculate change in matric suction and volumetric strain in the plastic zone surrounding a pressuremeter by using actual pressuremeter results and laboratory-determined soil-water characteristic curves. Top

TITLE: Kinetics of Coalescence in Linker Modified Microemulsions

Abstract: This project conducted thermodynamic (equilibirum) studies on the use of linker molecules to improve surfactant microemulsion systems, which could be used to form more environmentally friendly cleaning solutions. This inquiry helped to expand ongoing work to evaluate the kinetic behavior of microemulsions made with linker molecules. It allowed us to demonstrate that linker molecules not only improve the equilibrium nature of microemulsion systems but also the kinetic behavior of these cleaning solutions. This is very important, as the typical wash cycle is only 10-15 minutes, even if the equilibrium behavior is better the system may not be viable if the kinetics are slower. Top

TITLE: Nonlinear, Dynamic Behavior of Compacted Soil

Abstract: This project studied the cyclic behavior of unsaturated soils to determine specific soil properties that would assist with intelligent compaction processes. Cyclic triaxial testing of unsaturated soil specimens in the University of Oklahoma laboratories was performed. Work with the Oklahoma Department of Transportation personnel helped to prepare uniform samples for testing. A macro using MS Excel to reduce the significant quantiity of data was developed. Through data analysis, the evolution of dynamic modulus and energy dissipation as a function of modeling moisture content and dry density was explored. The findings helped to advance the study into the use of soil for intelligent processes. Top

TITLE: The Degradation of Carbon Tetrachloride in NaHS-Enriched Iron Bearing Mineral Environments

The results of this research provided preliminary data showing that iron minerals amended with bisulfide are reactive in the transformation of chlorinated organic ground water pollutants. The results also showed that phthalate, a compound containing aromatic and carboxylic functional groups typical of natural organic matter, has the potential to increase pollutant degradation rates under some conditions. Together these preliminary results will be used to design additional experiments to determine whether modification of iron bearing soils by the addition of bisulfide, either chemically or through the action of sulfate-reducing bacteria, is a feasible method for remediating certain polluted ground waters. Completion of these additional experiments will lead to a publication in a peer reviewed journal. Top

TITLE: Development of a High-Speed Automated Device to Measure Surface Tension as a Function of Composition

The objective of this work was to design and construct an automated device for rapidly measuring surface tension while varying the composition of a liquid mixture. An intended application of the device was measurement of surface tension of surfactant mixtures for determining critical micelle concentrations. The objectives of this work required development of methods for solving two different sub-parts of the problem: 1. the reproducible titration of two fluids (to produce the variation in composition), and 2. measurement of surface tension. To titrate the fluids, a system was developed based on pneumatically-controlled reservoirs. For the surface tension measurement, several methods were considered, including bubble pressure and oscillating jet methods; ultimately, the drop weight method was selected, and a photo-sensitive drop counter was constructed. Ultimately, the drop counter proved to be very successful, allowing automation of surface tension measurements for a fluid. The titration system, however, was unstable and difficult to calibrate, likely as a result of the low-cost automated pressure regulators selected for the project. The photo-sensitive drop counter developed will be used for future automated measurements, in combination with an HPLC pump to control flow.

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