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 70 for “"Porewater"”.
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Seismic site response analysis with porewater pressure generation
Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2025-08-01
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Climatic Controls on the Porewater Chemistry of Mid-continental Wetlands
… for atmospheric carbon. The chemistry of wetland porewaters impacts near-surface biological communities and subsurface biogeochemical processes that influence carbon cycling in the environment. Wetland porewater chemistry is a dynamic byproduct of complex hydrogeological processes that cause …
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Polyethylene passive samplers for measuring hydrophobic organic chemical concentrations in sediment porewaters and their use in predicting bioaccumulation in soft-shell clams (Mya arenaria) from sites near Boston, MA
… PRCs, impregnated into the PE before use, allow porewater concentrations to be deduced after exposure times much shorter than would be required for sampler equilibration (days instead of months). Next, the method is expanded for measuring suites of compounds of the same class. A one-dimensional …
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Application of diffusive gradient in thin-film passive samplers to assess mercury availability and mobility in a fresh water river system
The accurate measurement of mercury in sediment porewater is a challenge using conventional sampling techniques which commonly require removal of sediment, transportation, and processing. Passive sampling is an alternative technique that measures sediment porewater concentrations in-situ and …
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Mercury in water, porewaters, sediments and fish from the Medway Estuary, Southeast England
… likely to cause adverse affects to organisms. Porewater mercury concentrations ranged between <0.01-1.75 µg L-1, and were not correlated with mercury in the solid phase. The lowest partition ratio between mercury concentrations in sediment and porewaters was observed at four locations in the …
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Effects of drift macroalgae on sediment nitrogen cycling in Thalassia testudinum beds of St. Joseph Bay, FL
… and macroalgae biomass measurements, and porewater chemistry were analyzed to compare sediments in areas with and without macroalgae cover. Seagrass aboveground and belowground biomass was significantly greater in areas with no macroalgae on June 18, and 26. Sediments at incubation sites …
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The combined effects of salinity and sulfide on the growth and physiology of the freshwater marsh plant Pancium hemitomon J.A. Schultes
… the combined effects of increased salinity and porewater sulfide concentrations. I conducted a series of experiments to address the primary hypothesis that growth of Panicum hemitomon is adversely affected by an interaction between salinity and sulfide stresses associated with saltwater …
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Soil-derived dissolved organic matter cycling at terrestrial-aquatic interfaces: Implications for wetland-dominated landscapes, stormwater control measures, and drinking water supply
… the concentration and composition of DOM in soil porewater. Porewater DOM concentrations were sustained over the 40-days, supporting the hypothesis that wetland soils can act as quasi-infinite sources of DOM. As experimental saturation progressed, DOM composition shifted towards more aromatic, …
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The Fate and Mobility of Heavy Metals in East Anglian Salt Marsh Sediments
… dichotomy that exists; the anoxic sedimentary porewater beneath ponds either contains high concentrations of ferrous iron or aqueous sulfide, which are somewhat comparable to the ferruginous and euxinic ocean sediments of the mid-Proterozoic respectively. I found that proximity of tidal creeks …
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Plant productivity and diversity in coastal wetlands in Mississippi – impact of hydrological extremes
… and diversity changed with elevation and soil porewater salinity, and linked vegetation productivity to spectral information of Landsat and Sentinel satellite images. I applied the models to hindcast vegetation productivity based on historical satellite images approximately during May and …
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Short term effects of hypoxia and anoxia on sediment biogeochemistry
… transport, oxygen uptake, nutrient fluxes, porewater chemistry, and enzyme activities) was quantified. Bromide used in solute transport assessments were analysed using inductively coupled plasma mass spectrometry and oxygen was measured using an oxygen minielectrode. Nutrient analysis was …
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Elemental content to rice grain related to growing regions and soil microbiology
… and As species in those samples. Soil and porewater chemical parameters such as pH, Eh, SOC were measured and kinked with element concentrations in soil and porewater. Moreover, bacterial DNA was extracted from paddy soils and log2 copy number of 16S rRNA and arsM genes were detected using …
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Mat Movement in Coastal Louisiana Marshes: Effect of Salinity and Inundation on Vegetation and Nutrient Levels
… as well as the nutrient distribution in the porewaters and sediment. The effects of the physical differences in the two marsh types on the ocurrence of the dominant emergent vegetation was discussed.</p> <p>The main difference in physical structure of the two marsh types was the presence of a …
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Compressibilidade unidimensional da argila cinza do Rio de Janeiro em Botafogo
… the use of back pressure and the measurement of porewater pressure on the non-drained surface. Comparisons are made between parameters from laboratory tests and those obtained from in situ observations. A method is presented for computation of the volumetric compressibility versus effective …
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Ground improvement using vacuum preloading together with prefabricated vertical drains
… of induced settlements, interpretation of porewater pressures, nature of lateral displacements, and increase in undrained shear strength due to vacuum preloading. As a consequence, modifications to existing consolidation theories and separate design procedures have been proposed to …
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Phosphate-mineral interactions and potential consequences for nutrient cycling
… to be the dominant phase associated with rapid porewater-solid P exchange. Additionally, a seasonal enrichment/depletion pattern of phosphate fluxes relative to total carbon was observed from the sediments. These observations established the behavior of phosphate in coastal sediments as …
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Phosphate-mineral interactions and potential consequences for nutrient cycling
… to be the dominant phase associated with rapid porewater-solid P exchange. Additionally, a seasonal enrichment/depletion pattern of phosphate fluxes relative to total carbon was observed from the sediments. These observations established the behavior of phosphate in coastal sediments as …
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The marine geochemistry of iron and iron isotopes
… tows, river samples, aerosol leachates, and porewater samples were measured for their iron isotopic composition using a GV Instruments IsoProbe Multi-collector ICPMS. The Fe isotopic composition of plankton tow samples vared by over 4% (in 56Fe/54Fe). North Pacific plankton tow samples had …
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