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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
481

Particle Separation Through Taylor-couette Flow And Dielectrophoretic Trapping

Bock, Christopher Paul 01 January 2010 (has links)
As the world population approaches seven billion, a greater strain is put on the resources necessary to sustain life. One of the most basic and essential resources is water and while two thirds of the earth is covered by water, the majority is either salt water (oceans and seas) or it is too contaminated to drink. The purpose of this project is to develop a portable device capable of testing whether a specific source of water (i.e. lake, river, well…) is potable. There are numerous filtration techniques that can remove contaminants and make even the dirtiest water clean enough for consumption but they are for the most part, very time consuming and immobile processes. The device is not a means of water purification but rather focuses on determining the content of the water and whether it is safe. Particles within the water are separated and trapped using a combination of a Taylor Couette fluid flow system and Dielectrophoretic electrodes. This paper explores Taylor Couette flow in a large gap and low aspect ratio system through theory and experimentation with early stage prototypes. Different inner cylinder radii, 2.12cm, 1.665cm and 1.075cm, were tested at different speeds approaching, at and passing the critical Taylor number, 3825, 4713 and 6923 respectively for each cylinder. Dielectrophoretic (DEP) electrodes were designed, fabricated, coated and tested using latex beads to determine the method of integrating them within the fluid flow system. Taylor Couette theory, in terms of the formation of vortices within the large gap, small aspect ratio system, was not validated during testing. The flow pattern generated was more akin to a chaotic circular Couette flow but still served to move the particles toward the outer wall. Fully integrated tests were run with limited success. Recommendations were made to pursue both circular Couette flow as the basis for iv particle separation and dimensional changes in the setup to allow for the formation of Taylor vortices by increasing the radius ratio but still allowing for a larger volume of fluid.
482

Effects of season and temperature on the susceptibility of stream insects to a common organophosphate insecticide/

Shank, Richard L., (Richard Leroy), January 1984 (has links)
No description available.
483

A Stormwater Overflow Control Device

Stalker, Richard Duke 01 January 1973 (has links) (PDF)
On Lake Eola, stormwater runoff has been identified as a major source of pollution. Other lakes in Central Florida are experiencing similar decay due to stormwater runoff. A device has been examined for diversion of the initial flows to treatment before discharge into the lake. A graphical aid was developed to select the proper volume required for the device and was applied to a Lake Eola existing collection basin. A laboratory model was designed and constructed based on the scaled-down version of a collecting basin on Lake Eola. This model was used to demonstrate the concept, as well as, indicate the effects of several critical design variables. Recommendations on design for a Lake Eola device were made for possible improvements in the system itself.
484

The Simulation and Water Quality Characterization of a Coal Slurry Involving Eastern Coal

Todd, Michael R. 01 January 1983 (has links) (PDF)
The water quality characteristics of a coal slurry were found to vary widely, depending upon the coal used and the use of a corrosion inhibitor. The coal-water interactions were evaluated in a pilot-plant closed-loop coal slurry pipeline. Pulverized coal from eastern Kentucky and tap water were slurred and pumped through a 40 foot (12.2 m) pipe loop for ten days. Slurry samples were collected at 3 hours, 7 hours, 1 day, 2 days, 4 days, 7 days and 10 days from the start of a run. The samples were filtered and analyzed for 29 water quality parameters, including 15 metals. Two runs were performed without adding a corrosion inhibitor and two runs were performed with the addition of a corrosion inhibitor. The coal slurry filtrate contained high levels of sulfates, total dissolved solids, conductivity, acidity, iron, magnesium, manganese, lead and aluminum. The pH dropped initially, depending upon the percent sulfur in the dry coal and the alkalinity in the slurry, but returned to 6-7 after 10 days in the pipeline. Metal concentrations were a function of the pH, which affected solubility. Organics in the filtrate were at low levels. The addition of a corrosion inhibitor increased the concentrations of most parameters.
485

Impact of Highway Bridge Runoff on Adjacent Receiving Water Bodies

Christopher, James E. 01 July 1980 (has links) (PDF)
Two locations, Lake Ivanhoe and the Maitland interchange of Interstate 4, were selected to study the impact of bridge runoff on receiving water bodies. The Lake Ivanhoe location includes two similar bridges, one without scuppers and one with scuppers. The Maitland interchange site has several borr ponds which drain to Lake Lucien. Samples were collected from Lake Ivanhoe below the bridges and in the open lake away from the bridges. Also samples were collected from the east pond, west pond, and lake Lucien, at the Maitland interchange. Samples included water, sediments, plants and benthos to detect differences, if any, in heavy metal concentration due to sampling location. Heavy metals tested included: ZN, Cu, Cr, Cd, Pb, As, Fe, and Ni. Dissolved oxygen, temperature profiles and secchi desk transparency were measured in the field. Additional water quality parameters such as pH, turbidity, carbon and phosphorus were evaluated. Results indicated significant differences in specific heavy metal concentrations exist between samples collected beneath a bridge with scuppers compared to samples collected beneath a bridge without scuppers. Also, the drainage ponds appear to contain more heavy metals than the adjacent Lake Lucien at the Maitland interchange.
486

A Study of Assimilative Capacities for Receiving Streams

Elmi, Hadi. 01 January 1975 (has links) (PDF)
Literature reviews on various stream processes which contribute to reoxygenation and deoxygenation was presented. These processes include atmospheric reaeration, photosynthesis-respiration, biochemical oxygen consumption, and benthic demand. Measuring these parameters in a selected stream is a complex and costly operation. On the other hand, prediction models developed are specific to particular location and environmental conditions and can only be applied to similar situations. Computer models such as "RIVER" are available and could be used to predict dissolved oxygen concentrations along a waterway for a specified set of stream conditions. The model "RIVER" was calibrated by using the existing conditions of flow and water quality parameters along Phillippi Creek, Sarasota County, Florida. Also treatment requirements which could eliminate dissolved oxygen violations were predicted.
487

Wastewater Characterization and Treatability for anEastern Coal Slurry

Flint, Mark J. 01 January 1984 (has links) (PDF)
A complete wastewater characterization study was performed on an eastern Kentucky coal slurry after a 10-day circulation period in a 40 foot (12.2 m) pilot-scale pipeline. The resulting wastewater was settled and decanted for additional lime and alum treatability studies. Easter coal slurries were characterized by high TDS, conductivity, sulfates and iron. Significant concentrations of a number of trace metals were also found; however, organics were very low. Wastewater quality varied considerably among several experiments and was presumed to be influenced by different properties of the coal and the addition of a corrosion inhibitor. The major treatment concern was removal of high concentrations of iron, manganese, and trace metals if wastewaters were to be discharged. Lime treatment was found to effectively remove iron, magnesium, manganese and many other trace metals from coal slurry wastewaters. Alum treatment methods were considerably less effective for metals removal; however, alum was more effective in removing organics, color and turbidity. The addition of a corrosion inhibitor was found to reduce treatment removals for both lime and alum treatment. Several alternative uses were proposed for slurry wastewaters based on predicted water quality and volumes.
488

Biotoxicity of Highway Runoff Metals to GAMBUSIA

Bateman, John M. 01 January 1984 (has links) (PDF)
A research study was conducted to examine the relationship between speciation of heavy metals (Zn, Cd, Pb, Cu) and their biotoxicity. Therefore, static bioassay experiments were designed to determine LC-50 values for those metals on mosquitofish, Gambusia affinis. The standard bioassay scheme consisted of twelve 16-liter all-glass aquaria that provided duplicates of five different metal concentrations and a control for each run. Deionized tap water and filtered retention/detention water from Maitland Pond were used for bioassays. The effects of various physiochemical parameters such as pH, alkalinity, hardness and organic complexation on metal toxicity were determined. Also, synergistic and antagonistic effects resulting from metal mixtures were examined. It was concluded that metals in pond water were considerably less toxic than in deionized water for mosquitofish. Also, copper was consistently the most toxic metal tested for both deionized water and pond water.
489

Spruce Creek Watershed Non-point Source Loading Model

Smoot, James L. 01 January 1977 (has links) (PDF)
The pollutant transport from watershed to receiving waters is modeled for Spruce Creek basin. The data requirements for such a model are: daily rainfall; monthly lake evaporation; soil and land use breakdown; water quality history for the main indicators, total nitrogen, total phosphorus, suspended solids, and total organic carbon; surface flow and interflow delay coefficients; channel flow time; daily flow gage records; and channel flow characteristics. The model uses the SCS runoff curve number method to generate rainfall excess where the antecedent conditions are varied daily by a water budget analysis. The direct runoff is delayed and routed by the CDET and Muskingum method respectively. Daily pollutant loading are generated by the use of pollutant loading functions which relate pollutant mass loading to average daily flow for the pollutants desired. These are totaled for each year of simulation to predict average pollutants loading from the water shed in pounds per acre per year for use in water quality planning.
490

Stormwater Runoff from Shopping Centers

Donigan, Thomas P. 01 January 1975 (has links) (PDF)
This is a brief investigation of stormwater runoff from a large shopping center located in Brevard County, Florida. Merritt Square Shopping Center has a parking area for 4,700 automobiles and is located on the shore of Newfound Harbor which is classified as recreation waters (Class III). A literature survey of runoff studies in other areas has been made for both "state of the art" and evaluation of findings. Water samples were initially collected from five locations. Review of the analysis of these samples indicated that while color and turbidity appeared to decrease linearly with time, organic and inorganic concentrations did not. During a later storm a second series of samples was taken from a single location at two minute intervals. In the analysis of these samples the organic and inorganic carbon concentrations decreased with time from the beginning of the storm. However, an upturn in concentration in the final stages of runoff may be noticed.

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