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 17 of 17 for “"Subsurface transport"”.
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Measurement of Soil and Water-Quality Parameters to Understand Subsurface Transport Processes
… toward a better understanding of the flow and transport dynamics in saturated and unsaturated soils. In the first phase of this study, we have focused on understanding the impacts of climate change driven hydrological processes such as excess rainfall and/or draught cycles on saltwater …
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Subsurface transport of fertilizer-applied nitrogen on the eastern shore of Virginia
… Root Zone Model) was used to simulate the transportation of nitrogen through the soil column, past the crop root zone to groundwater. Then MOC (Method of Characterization), a groundwater model, was used to transport the nitrogen that had reached the water table offsite. Results were …
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Numerical Solution Techniques for Reaction Parameter Sensitivity Coefficients in Multicomponent Subsurface Transport Models
For reactive transport, the state equations consist of a nonlinear PDE for each aqueous component and a nonlinear ODE for each immobile component; these differential equations are coupled together through reaction source/sink terms. The corresponding sensitivity equations take the form of a system …
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The effect of fluid acceleration on sediment transport in the surf zone
… consequences of this dissimilarity on sediment transport is not fully understood. This thesis develops methodologies to predict sediment transport under these asymmetric, skewed waves. Two different transport mechanisms are considered: bedload transport and "subsurface" transport. The potential …
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Modeling and monitoring pathogen transport through vegetated filter strips
… of vegetated filter strips (VFS) on surface and subsurface transport of fecal oviform (FC) surrogates for bacterial pathogens released from a surface - applied bovine/swine manure. The study included a field-based lysimeter equipped with multi-sensor moisture probes to monitor real-time water …
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Effect of atmospheric variations on subsurface flow and transport
… the effect of atmospheric variations on subsurface flow and transport at the proposed high level waste repository at Yucca Mountain, Nevada. The conditions of subsurface transport were simulated with NUFT (Nonisothermal Unsaturated-Saturated Flow and Transport model) modeling software …
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Anticipation nationwide risks to drinking water : predicting local scale contamination of community supply wells by gasoline additives
… MTBE has migrated in significant quantities from subsurface gasoline spills to a substantial number of community and private drinking water wells in a short period of time. For the purposes of this project, it was hypothesized that the tendency for gasoline additives to contaminate subsurface …
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Modeling Stormwater Pollutant Transport in a Karst Region--Bowling Green, Kentucky
… as it is transferred through conduits in the subsurface and the buildup of pollutants underneath can be detrimental to community and environmental health if not effectively mitigated. Because of the limited resources available to determine how stormwater runoff carries potential pollutants …
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Investigation of Partial Contributing Areas in Watersheds With a Conjunctive Surface Subsurface Flow Model
… two-dimensional surface three-dimensional subsurface transport to simulate the total runoff in watersheds. In conjunction with the CFM, an overland flow-tracking program (OFTP) was developed to compute the PCA under the proposed definitions. The model can compute the saturated area (SA), …
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Investigating uranium mobility using groundwater 238U/235U data and a reactive transport model
… understand chemical reactions affecting the subsurface transport of the widespread contaminant uranium (U), we present a numerical reactive transport model which explicitly incorporates variations in the 238U/235U isotope ratio. Bioremediation, the microbial reductive immobilization of …
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Concentration and distribution of organic phosphorus through a grassland catchment transfer continuum
… continuum from soils to surface and sub-surface transport pathways and ultimately into the stream water channel, within the River Eden catchment in Cumbria, England. The aims of the study were to: (i) quantify the magnitude of different P compounds, including DNA-P and PLD-P, in grassland …
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Numerical Modeling and Simulation of Mineral Dissolution in Fractured Carbonate Formations
Mineral dissolution plays important role in many subsurface transport processes including waterflooding, geological CO2 sequestration (GCS), and matrix acidizing in carbonate formations. Such a dissolution process could form the preferential pathways to cause a failure of waterflooding and GCS due …
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The Hillslope Hydrology of a Mountain Pasture: The Influence of Subsurface Flow on Nitrate and Ammonium Transport
… enter aquatic ecosystems through surface and subsurface hydrological transport that drain agricultural watersheds. The over-abundance of nitrogen within these watersheds is easily transported to receiving stream and rivers, and result in aquatic ecosystem degradation. In response to the …
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Structure-Preserving High Performance Computational Methods for Transport in Porous Media
… of numerical methods for large-scale subsurface transport applications. With increasing capacity and complexity of processors and memory systems, the need for improving the performance of subsurface flow and transport simulations has become an area of active research. Two of the most …
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Influence of pH and NOM on Sorption of Phenols onto Aquifer Material
… an important role as retardation mechanism in subsurface transport of organic water constituents. Geosorption behaviour of Ionisable Hydrophobic Organic compounds (IHOCs) especially influence of dissolved natural organic materials on their sorption coefficients is poorly investigated. In this …
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An analysis of solute transport on a harvested hillslope in the southern Appalachian Mountains
Interest in transport of dissolved nitrogen (N) and carbon (C) in forested ecosystems is growing because of potential effects of these solutes on streamwater quality and implications for C sequestration. Additional research will further the understanding about the dynamics of these soil solutes, …