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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.
511

The Mineral Resources of the Sevier River Drainage, Central Utah

Sanders, David T. 01 May 1962 (has links)
A survey of the mineral resources, the economic rock products, and the ground-water reserves of that part of central Utah drained by the Sevier River system was undertaken by the author in the fall of 1960 as a continuation of a research project directed toward the stiumulation of economic growth in the state of Utah. The project was initiated in 1959 by Dr. Donald R. Olsen and Dr. J. Stewart Williams, who conducted a similar survey of a five county area in southwestern Utah (Olsen and Williams, 1960). Through a review of existing literature, preliminary field examination of most of the important areas, and communications with owners, operators, and consulting geologists, an attempt has been made to include in this survey all of the important economic mineral and rock deposits. A review of the ground-water supplies of the region and a discussion of related problems are also included. Each of the minerals and rock products is described alphabetically in a brief statement. This statement includes information concerning location, present status, present ownership, and geologic controls of accumulation. Where possible an estimate of the economic potential of each commodity is made. These estimates are based on accessibility, tonnage, grade, market value, etc. Each occurrence is also located on a map of the area.
512

Drainage of Land Overlying an Artesian Aquifer: Logan-Cache Airport

Riley, John Paul 01 May 1953 (has links)
Drainage problem Logan-Cache Airport is situated approximately 4 miles northwest of Logan, Utah, in sections 8, 9, 16, and 17, Township 12 north, Range 1 east, of Salt Lake Base and Meridian. The area of approximately 200 acres is a part of what is known as cache County Drainage District No.2. This district in itself contains more than 8,400 acres of waterlogged lands. Drainage of the se lands has, for many years, been a baffling and unsolved problem, complicated by 3 factors: (a) The whole of the valley in this area is underlain by an artesian ground-water reservoir. (b) The artesian aquifer is overlain by a layer of heavy clay of very lo~ permeability, ranging in depth from 40 to 70 feet. (c) Human relations with farmers within the area , who consider that drainage will deprive them of their plentiful groundwater Supply.
513

Sustainable urban pavement for cities affected by El Niño using porous concrete

Aguirre, B., Anchiraico, M., Rodríguez, J., García, F. 05 February 2021 (has links)
The El Niño phenomenon is caused by the change in atmospheric pressures, which produce the accumulation of hot surface waters on the eastern flank of the Pacific Ocean; causing intense rainfall that runs over the surface affecting the urban drainage of the city due to the lack of a permeable pavement; porous concrete allows infiltration of surface water runoff through its pores. The present investigation evaluates porous concrete in the range of w/c relationships of 0.30 and 0.32; the results indicate that the compressive strength, flexural strength and permeability coefficient increase; and that the surface runoff, cost, water footprint and carbon footprint are lower than conventional concrete.
514

Remediation Approach for Improving Acid Mine Drainage Conditions Using Slow Release Hydrogen Peroxide Systems

Wolbert, Ryan A. 02 June 2020 (has links)
No description available.
515

CONTAMINANTS REMOVAL AND RARE EARTH ELEMENTS RECOVERY FROM COAL MINE DRAINAGE BY USING (BIO)(ELECTRO) CHEMICAL METHODS

Peiravi, Meisam 01 August 2018 (has links) (PDF)
Mining activities, as essential as they are for our economy and our society, bring pollutants such as acid mine drainage (AMD) which contains dissolved metal(loid)s into the environment. There are different technologies currently being practiced to treat AMD, but many of these methods are prohibitive in industry due to high energy, material and labor requirements. This study investigated two emerging technologies to treat AMD with high removal rates of some metals. In addition, as AMD contains strategic metals such as rare earth elements (REEs), hydrometallurgical and biosorptive approaches were used to recover REEs from AMD, hydrometallurgical recovery method was also applied for coal by-products for the method developed. A two-chamber bioelectrochemical system (BES) was used to remove different types of metals from AMD. After 7 days, the pH of the cathode solution increased from 2.5 to 7.3. More than 99% of Al, Fe and Pb were removed, and removal rates of 93%, 91%, 89% and 69% were achieved for Cd, Zn, Mn, and Co, respectively, at the biocathode. Energy-dispersive X-ray spectroscopy (EDS) studies revealed the deposition of the various metals on the cathode surface, and some metals were detected in precipitates from the cathode chamber. During the BES operation, ~30-50 mV of closed circuit voltage was obtained for different conditions. A single-chambered BES study was conducted for the removal of Cd, Ni, and Mn in mine drainage. Compared to a double chamber, a single chamber BES is easier to design and operate. The removal process was studied with activated sludge from a local wastewater treatment plant. The effect of applied voltage, time, and initial concertation of these metals on their removal rate was studied. For Cd initial concentrations of 625 and 165 µg/L, 1.0 V showed the highest removal efficiency, and ~93 and 95% of Cd were removed, respectively. For a Ni initial concentration of 2,440 µg/L, 72% was removed under 1.0 V compared to the control of 77%. However, for a lower initial Ni concentration of 190 µg/L, 1.0 V was better compared than other conditions, and it removed 92% of Ni. For a Mn initial concentration of 1,800 µg/L, 1.0 V had a better result, however, only ~19% of the Mn was removed. For a lower Mn initial concentration of 390 µg/L, 1.0 V was favorable only at 24 h and the removal rate was ~37%. Nanoscale zerovalent iron (nZVI) was used to remove contaminants from AMD. These contaminants include transition metals (Co, Ni, Cu, Mn, and Zn), alkali and alkaline earth metals (Li, Mg, and Ca), metalloid (As), nonmetals (Se and S), and active metal (Al). Purchased nZVI in concentrations of 10-6500 mg/L was used for a reaction duration of up to 480 min. The pH of the AMD increased linearly with increasing concentrations of nZVI, with a maximum of 6.0±0.1 at 6500 mg/L of nZVI. Cu and Al had the highest removal rate among all other elements. With 10 mg/L of nZVI, ~100% of Cu was removed within 120 min. Up to ~98% of Al was removed with 5000 mg/L of nZVI in 480 min. Reuse of the purchased nZVI was studied for the first time for AMD treatment; however, after reuse in the second cycle, the nZVI was no longer effective. Lab-made nZVI by the precipitation method was tested for a longer time of 48 h. Removal rates for different elements did not change after ~8 h (e.g., 480 min), and in general, the lab-made nZVI had better removal efficiency compared to the purchased nZVI, with removal rate of ~28-79% when using 80 mg/L of the lab-made nZVI. Besides Cu, Al, Ni, and Co, successful removal of Mg and Ca, as well as S, Co, Li, As, and Se from AMD was reported for the first time by using nZVI. Different coal ranks were examined for REE concentration from coal ash. Maximum REE content of more than 700 mg/kg was observed for the highest-rank coal (anthracite) sample, and that was used for leaching and recovery studies. Hydrometallurgical processes including leaching, solvent extraction, stripping, and precipitation were performed to recover REEs from coal ash. Nitric acid leaching tests were conducted at 95 ℃ using a 4×2×2 factorial design. The results indicated that the highest rate of light REEs (LREEs) recovery was achieved at the highest molarity of the acid solution, lowest solids content and longest retention time. However, the highest rate of heavy REEs (HREEs) recovery needed only an intermediate level of acid molarity. The highest recovery rates of 90% for LREEs and 94% for HREEs were obtained. Recirculation of the leachate was conducted to prepare the REE-concentrated solution for the solvent extraction. After two stages of leaching, a 33 mg/L of TREE concentration was obtained in the leachate. Solvent extraction (SX) tests conducted using three different extractants, namely, TBP, D2EHPA and Cyanex 572, and their combinations showed that D2EHPA was the best extractant for recovering REEs from the nitric acid leachate solution with an extraction efficiency of 99%. Nitric acid and sulfuric acid and their mixture were used in the stripping tests. The effect of solvent concentration (in the SX process) was also studied in the stripping stage. When 50% solvent concentration was used, a maximum of 58% stripping recovery was obtained. Oxalic acid helped precipitate ~94% of total REEs (TREEs) from the above aqueous solution. Calcination of the product was performed to reach a final product of 0.8% rear earth oxides (REOs). The same process flowsheet was also successfully tested for another coal ash sample. To recover REEs from AMD, two different approaches were carried out including hydrometallurgical technique and more environmentally friendly approach- biosorptive recovery. A complete process flowsheet including either solvent extraction or biosorption, followed by stripping, and precipitation was developed to recover REEs from an unconventional source of AMD for the first time. At the natural pH of 2.5 almost all REEs were extracted from the solution. Metal-loaded organic solution was reused for three cycles, and it was shown that after three cycles, there was no major reduction in the capacity of the extractant. Striping with 6.0 M HNO3 recovered 23.9±0.7, 74.7±2.1, and 53.1±1.4% of LREEs, HREEs, and TREEs from the organic phase accordingly. Using oxalic acid, and for pH of 2.0, 92.9±2.8% of LREEs, 10±1.5% of HREEs, and 56.2±1.8% of TREEs were precipitated. In the biosorptive extraction, >99% of TREEs were extracted from the solution. The REE-bearing bacteria was also stripped with 6.0 M HNO3, 2871.3±114.8 µg/L (45.0±1.8%) LREEs, 3851.0±154.0 µg/L (65.0±2.6%) HREEs, and 6722.0±268.9 µg/L (50.0±2.0%) TREEs were obtained. Both hydrometallurgical and biosorptive methods extracted almost all of the REEs in the AMD, though pH was adjusted to 4.0 for the biosorptive method. After stripping, comparable amounts of TREEs were obtained by both methods.
516

Water quality monitoring and modeling studies of onarm water storage systems in a Mississippi Delta agricultural watershed

Perez-Gutierrez, Juan David 11 August 2017 (has links)
Federal and state programs have encouraged farmers in the Mississippi Delta region to implement best management practices (BMPs) to promote soil and water conservation. An onarm water storage (OFWS) system is a structural BMP that has several potential benefits, namely, the ability to capture and reuse rainwater and tailwater runoff, provide supplemental water for irrigation, reduce groundwater withdrawals, and improve downstream water quality. However, research demonstrating these benefits and providing new insights for downstream water quality improvement and nutrient-rich runoff management is limited. This dissertation addresses these research gaps by examining the ability of OFWS systems to mitigate off-site nutrient movement, analyzing the impacts of rainfall characteristics on the ability of OFWS systems to reduce NO3-N, studying the hydrological and physical-chemical characteristics of the volume of water exiting an OFWS system, and using the AnnAGNPS model to simulate runoff, nutrient, and sediment loads entering a tailwater recovery ditch and identify the critical contributing areas of non-point source pollution. Significant seasonal water quality improvements were observed at different locations throughout the OFWS system, and more importantly, highlight downstream nutrient reduction, particularly during winter and spring. However, recurrent and high intensity rainfall events can minimize the system’s effectiveness in reducing downstream nutrient pollution. The NO3-N concentrations observed in the ditch were strongly dependent on antecedent hydrological conditions with characteristics of next-to-last rainfall events playing a more influential role. The nutrient load was greater in winter, as this season produced the highest effluent discharge. Agricultural fields draining to the outlet of the system produced 7.1 kg NO3-N ha-1yr-1 and 2.3 kg TP ha-1yr-1 that was discharged with outflow events. AnnAGNPS simulations showed that larger fields coupled with poorly drained soils resulted in higher runoff, and this condition mirrored the annual rainfall patterns. High nitrogen loss was due to fertilization of corn and winter wheat. TP and sediment loss patterns were similar and influenced by the hydrological condition. This study can be used by stakeholders and agencies to better identify where these systems can be implemented to improve water quality and offer a supplemental source of surface water.
517

The nature of ochre deposition and drain blockage in a fine sandy loam soil.

Gameda, S. January 1981 (has links)
No description available.
518

Roughness factors and water conveyance capacities of corrugated plastic tubing

Pelletier, Marc-Antoine. January 1984 (has links)
No description available.
519

Investigations into the performance of a subsurface irrigation system in a clay soil

Plante, André January 1992 (has links)
No description available.
520

Use of soil and vegetative filter strips for reducing pesticide and nitrate pollution

Liaghat, Abdolmajid January 1997 (has links)
No description available.

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