Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 237 for “"Leached"”.
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Uranium Leached From Pre-1970's Ceramic Dinnerware
… radiation monitor. Results show that lead can be leached from the orange ceramics in excess of 100 times the maximum allowable ingestible limits. Uranium levels in the orange ceramicware leachates ranged as high as 30 times the maximum allowable intake of 4 mg per day. All three types of …
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The Leached Layer Formed On Wollastonite In An Acid Environment
… the rate of dissolution and the development of a leached layer on wollastonite. Each experiment ran for approximately 24 hours and the release rates of Si and Ca in the interval from 14 to 24 hours were analyzed. Each experiment began with an incongruent stage where Ca was released faster than the …
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Leached chrysotile asbestos : characterization, leaching mechanism and use in the synthesis of zeolites
… both silica gel (conventional method) and leached asbestos (new method). In a kinetic study of the crystallization of Na-A zeolite, it was found that leached asbestos is clearly more efficient than silica gel for the preparation of zeolites
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The elastic properties of calcium leached cement pastes and mortars : a multi-scale investigation
… on the elastic modulus of asymptotically leached cement paste and mortar. A combined qualitative-quantitative approach is adopted to characterize and quantify the chemical degradation at various length scales. The macroscopic elasticity (10-2 - 10-4 m) is measured using three different …
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Retardance of rainwater-leached metals from CCA-treated (chromated copper arsenate) wood ash in soil
The burning of wood treated with chromated copper arsenate (CCA) preservative produces an ash that contains high concentrations of copper, chromium, and arsenic. The subsequent leaching of these metals from burn sites can produce soil and water contamination. Soils have varying natural abilities to …
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Synthesis of Acid Leached Diatomaceous Earth/ Amine-Functionalized Activated Carbon Composite and its Potential Application in Oily Wastewater Treatment
… aim of this project is to synthesize acid-leached diatomaceous earth (DE) and amine-functionalized activated carbon composite adsorbent for the treatment of oily wastewater. Acid leached diatomaceous earth was synthesized by leaching the raw diatomaceous step-wisely in a 120 mL volume of …
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The chemical response of deep, leached and weathered soils of the Mpumalanga Highveld, South Africa, to irrigation with saline mine water
Coal mining in the Highveld region of Mpumalanga Province, South Africa generates between 14 and 30 million litres of waste water per day. Much of the water is saline (TDS> 2500 mg/I) and has high concentrations of dissolved SO₄²⁻, Ca²⁺ and Mg²⁺. Crop irrigation has been proposed as a useful way to …
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Toxicity characteristic leaching procedure analysis of dye containing sludges
… metals and other organic compounds which also leached were identified. Only small amounts of color were detected in the TCLP extracts; the mean ADMI color values for undigested and aerobically digested sludges were 240 and 156 ADMI color units respectively. Concentrations of individual dyes …
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Characterization of volcanic ash from 2010 Mt Merapi, Indonesia eruption by neutron activation analysis and leaching analysis
… activation analysis techniques. The ash was then leached into slightly acidic distilled water meant to simulate rainwater. This thesis focuses both on the methods used to identify the elements present in the ash, as well as the possible impacts of the results. The research included the use of both …
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Effect of urinary nitrogen, dairy shed effluent and nitrogen fertiliser on nitrate leaching from a pasture soil
… the concentrations and quantities of nitrate-N leached were determined from the two year lysimeter experiment. The role of macropore flow on nitrate-N leaching was determined in a second lysimeter experiment. The results from the two year experiment were also used to test the accuracy and the …
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Avaliação da qualidade de diferentes marcas de chá verde (Camellia sinensis) comercializadas em Salvador-Bahia
… carried through of: humidity, activity of water, leached ashes, insoluble leached ashes in acid, microscopical evaluation of dirtiness and confirmation of the identity. The gotten results indicate that the samples in sachets had presented superior quality in bulk those presented how much to the …
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Investigation of calcium orthophosphate chemical effects in a post-LOCA nuclear reactor containment
Calcium leached from NUKON fiberglass in containment following a Loss of Coolant Accident (LOCA) could lead to the formation of chemical precipitates that in turn cause head-loss increase due to filtering through a fibrous debris accumulation at the sump pump screens. Experiments conducted on the …
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Effects of Rain and Simulated Rain on Deoxynivalenol Levels in Grain and Chaff of Winter Wheat with Fusarium Head Blight
… spike tissues and to quantify the amount of DON leached from spikes. Field experiments were conducted on susceptible and moderately resistant wheat cultivars affected by FHB utilizing spike holders to catch water leaching through groups of spikes, rain shelters to protect plots from rain and …
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Chemomechanics of calcium leaching of cement-based materials at different scales : the role of CH-dissolution and C-S-H degradation on strength and durability performance of materials and structures
… nitrate solution to obtain asymptotically leached specimens in short times. An acceleration rate of 300 compared to natural leaching is obtained. The strength domain of leached cement pastes and mortars is evaluated through triaxial compression tests and uniaxial tension tests, revealing an …
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Fossil preservation and the effects of groundwater leaching on fossils in the Yorktown Formation (Upper Pliocene), Virginia
… and fossiliferous layers. Groundwater also leached the Yorktown sediments. This alteration caused a diagenetic stratification of the sediment, with unaltered greenish-gray silty fine sand along the base of the outcrop, overlain by leached yellowish-brown silty fine sand and areas of …
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Properties of Waste Resulting from Arsenic Removal Processes in Drinking Water Treatment
… to determine the amount of arsenic that was leached to the liquid portion over time. Toxicity testing was performed on the residuals at 20% and 100% after two months and six months of storage. Bench-scale sand drying beds were used to dewater residuals, and the leachates were analyzed to …
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Developing an understanding of the relationship between the durability of simplified and complex UK radioactive waste glasses
… After characterising these glasses, they were leached in a mechanistic study to investigate the effects of Li on chemical durability. In addition to 7Li MAS-NMR and 6Li-1H CP-NMR, comprehensive 11B and 23Na MAS-NMR studies and SEM imaging of the leached glass surfaces then took place to …
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Comparison of gold extraction yields by cyanide treatment vs. bioleaching procedure
… tailings of the Picacho mine in California were leached using NaCN and native bacteria, <em>Alcaligenes faecalis,</em> in column experiments to compare the gold recovery yields in the effluents. Four columns were treated with a different liquid: water, bacteria, NaCN and a mixture of cyanide and …
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Assessing Potential Solutions to Mitigate Pollution from Neonicotinoid Seed Coatings
… in soybeans. Soils with increased organic carbon leached less thiamethoxam and clothianidin during early growing season leaching peaks; however, at the end of the season, higher organic carbon content only decreased leached mass of clothianidin. The second study was to determine neonicotinoid …
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Evaluation of Phosphorus Transport and Transformations in GLEAMS 3.0
… analysis showed that GLEAMS prediction of leached P were extremely sensitive to changes in the P partitioning coefficient (CPKD). Runoff PO₄-P output was slightly to moderately sensitive, sediment PO₄-P was moderately sensitive to sensitive, and sediment organic P was moderately sensitive …
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