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 12 of 12 for “"advection-dispersion equation"”.
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Assessment of scaling and information requirements of the classical advection dispersion equation and a temporal-nonlocal advection dispersion equation at the MADE site, An
The MacroDispersion Experiment (MADE) Site in Columbus, MS, is a research site where tracer tests have been performed to further understand transport processes in heterogeneous material. Tracer tests have exhibited anomalous plume behavior, including early arrival times and heavy, power-law …
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Quantifying non-Fickian transport in porous and fractured media using fractional-calculus based stochastic models
… from that described by the classical advection dispersion equation (ADE). The ADE describes the Fickian-type of transport, with symmetric snapshots like the Gaussian distribution in space (Berkowitz et al., 2006). Non-Fickian transport can be observed at all scales. Non-Fickian …
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Modeling event-based coupled hydrologic and mass transport in small urban watersheds
… The application of fractional calculus to the advection-dispersion equation was also investigated for the distributed system model. A novel mass transport model based on a unit pollutograph (UP) concept analogous to the unit hydrograph (UH) theory was proposed and successfully illustrated. A …
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Experimental analysis and modeling of transient dissolution of RDX through mass transfer processes
… employed to model the overall solute transport equation. The solute transport equation takes into account advection, dispersion, sorption, degradation, mobile-immobile sorption, and a mass transfer source term. Numerical code was developed and this model simulated the following: (1) flow rate, …
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Bacterial and Sediment Transport in an Artificial Sand Bed Stream During Unsteady Flow
… resuspension, we modeled the system using a 1-D advection-dispersion equation with added source/sink terms to account for sediment settling and resuspension. This experiment and its analysis may provide a methodology for determining coliform and suspended sediment inputs into total maximum daily …
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Solute transport in layered and heterogeneous soils
… dispersivities. Recently, a new governing equation, factional-order advection-dispersion equation (FADE) was proposed to describe transport processes in heterogeneous systems. We proposed a statistical method to justify the use of a FADE. A fractional order of 1.82 was confirmed to be …
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Lattice Boltzmann modeling for shallow water equations using high performance computing
… fields. The shallow water and mass transport equations have wide applications in ocean, coastal, and hydraulic engineering, which can benefit from the advantages of the LBM. The LBM has recently become an attractive numerical method to solve various fluid dynamics phenomena; however, it has …
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Development of a model for simulation of solute transport in a stream aquifer system
… The SSTM is coded based on the one-dimensional advection dispersion equation. The finite difference method is the numerical technique implemented in the SSTM. MSAST is used to simulate chloride transport in the stream-aquifer system of the Arkansas River and the Equus Beds Aquifer in …
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Efficiency of soil aquifer treatment in the removal of wastewater contaminants and endocrine disruptors. A study on the removal of triclocarban and estrogens and the effect of chemical oxygen demand and hydraulic loading rates on the reduction of organics and nutrients in the unsaturated and saturated zones of the aquifer.
… conditions was modelled successfully with the advection dispersion equation with coupled Monod kinetics. Empirical models were also developed for the removal of TCC and EE2 under saturated and unsaturated conditions respectively. The empirical models predicted the TCC and EE2 removal profiles …
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Stochastic modelling of contaminant transport in porous media
… impacts. This gives a stochastic differential equation for fluid displacements, and solute transport is obtained as the cumulative effect over all realisations of the stochastic path. It is shown that applying Dynkin’s equation to obtain expectation values over realisations, a time and space …
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Simulation and assessment of highly altered hydrologic system responses to anthropogenic and natural stressors at the watershed scale
Environmental stressors account for human activities and natural processes that provoke modification of an ecosystem and its behavior. These stressors are chemical, physical, or biological in nature and can have short- and long-term impacts on the ecosystem (EPA, 2017b). Watershed Management …
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Fate and impact of antibiotics in slow-rate biofiltration processes.
… batch experiments. A one-dimensional advection-dispersion equation (with linear sorption) model was validated against experimental results and used to compare antibiotic retardation in SSF, RBF, and rapid gravity biofiltration (RGBF) systems. Of the modeled systems, antibiotic …