Search Results - "Valocchi, A.J"

Application of Jacobian-free Newton–Krylov with physics-based preconditioning to biogeochemical transport by Hammond, G.E., Valocchi, A.J., Lichtner, P.C.

“…Modern multicomponent geochemical transport models require the use of parallel computation for carrying out three-dimensional, field-scale simulations due to…”
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Quantitative Evaluation of the Enhancement of NAPL-Pool Dissolution by Flushing and Biodegradation by Seagren, Eric A, Rittmann, Bruce E, Valocchi, Albert J

“…Quantitative tools and criteria for assessing the effects of flushing and biodegradation of nonaqueous-phase liquid-pool dissolution are discussed. Evidence…”
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Two-dimensional concentration distribution for mixing-controlled bioreactive transport in steady state by Cirpka, Olaf A., Valocchi, Albert J.

“…Under steady-state conditions, the degradation of contaminant plumes introduced continuously into an aquifer is controlled by transverse dispersion when the…”
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A numerical framework for diffusion-controlled bimolecular-reactive systems to enforce maximum principles and the non-negative constraint by Nakshatrala, K.B., Mudunuru, M.K., Valocchi, A.J.

“…We present a novel computational framework for diffusive–reactive systems that satisfies the non-negative constraint and maximum principles on general…”
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Estimating transmissivity from the water level fluctuations of a sinusoidally forced well by Mehnert, E, Valocchi, A.J, Heidari, M, Kapoor, S.G, Kumar, P

“…The water levels in wells are known to fluctuate in response to earth tides and changes in atmospheric pressure. These water level fluctuations can be analyzed…”
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Non-negative mixed finite element formulations for a tensorial diffusion equation by Nakshatrala, K.B., Valocchi, A.J.

“…We consider the tensorial diffusion equation, and address the discrete maximum–minimum principle of mixed finite element formulations. In particular, we…”
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Pore-scale simulation of dispersion and reaction along a transverse mixing zone in two-dimensional porous media by Acharya, R.C, Valocchi, A.J, Werth, C.J, Willingham, T.W

“…Several studies have demonstrated that the success of natural and engineered in situ remediation of groundwater pollutants relies on the transverse mixing of…”
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Pore-scale simulation of biomass growth along the transverse mixing zone of a model two-dimensional porous medium by Knutson, C.E, Werth, C.J, Valocchi, A.J

“…The success of in situ bioremediation projects depends on the mixing of contaminants and nutrients in the presence of microbes. In this work, a pore-scale…”
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Finiteness of steady state plumes by Liedl, R, Valocchi, A.J, Dietrich, P, Grathwohl, P

“…The finite maximum length of a steady state contaminant plume is determined by developing and employing a new analytical solution which overcomes two drawbacks…”
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Effect of soil moisture dynamics on dense nonaqueous phase liquid (DNAPL) spill zone architecture in heterogeneous porous media by Yoon, Hongkyu, Valocchi, Albert J., Werth, Charles J.

“…The amount, location, and form of NAPL in contaminated vadose zones are controlled by the spatial distribution of water saturation and soil permeability, the…”
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Multicomponent transport with coupled geochemical and microbiological reactions: model description and example simulations by Tebes-Stevens, Caroline, J. Valocchi, Albert, VanBriesen, Jeanne M., Rittmann, Bruce E.

“…A reactive transport code (FEREACT) has been developed to examine the coupled effects of two-dimensional steady-state groundwater flow, equilibrium aqueous…”
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Magnetic resonance imaging of nonaqueous phase liquid during soil vapor extraction in heterogeneous porous media by Chu, Yanjie, Werth, Charles J., Valocchi, Albert J., Yoon, Hongkyu, Webb, Andrew G.

“…Soil vapor extraction (SVE) is commonly used to remediate nonaqueous phase liquids (NAPLs) from the vadose zone. This paper aims to determine the effect of…”
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An experimental investigation of NAPL pool dissolution enhancement by flushing by Seagren, Eric A., Rittmann, Bruce E., Valocchi, Albert J.

“…Experiments coupled with mathematical modeling are used to further elucidate the quantification of NAPL pool dissolution and its enhancement by water flushing…”
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Integrating data sources to improve hydraulic head predictions: A hierarchical machine learning approach by Michael, W.J, Minsker, B.S, Tcheng, D, Valocchi, A.J, Quinn, J.J

“…This study investigates how machine learning methods can be used to improve hydraulic head predictions by integrating different types of data, including data…”
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An improved dual porosity model for chemical transport in macroporous soils by Ray, Chittaranjan, Ellsworth, Timothy R, Valocchi, Albert J, Boast, Charles W

“…The often observed processes involved in preferential water flow and chemical transport in porous media appear to be realistically described using a…”
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Efficient numerical techniques for modeling multicomponent ground-water transport based upon simultaneous solution of strongly coupled subsets of chemical components by Robinson, Bruce A., Viswanathan, Hari S., Valocchi, Albert J.

“…An iterative solution technique for reactive transport problems is developed, which we call the selective coupling method, that represents a versatile…”
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Characterization of travelling waves and analytical estimation of pollutant removal in one-dimensional subsurface bioremediation modeling by Oya, S. (University of Illinois, Urbana.), Valocchi, A.J

“…We study the behavior of solute fronts for an in situ bioremediation scenario in which a sorbing substrate is degraded by indigenous microorganisms in the…”
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A critical evaluation of the local-equilibrium assumption in modeling NAPL-pool dissolution by Seagren, Eric A, Rittmann, Bruce E, Valocchi, Albert J

“…An analytical modeling analysis was used to assess when local equilibrium (LE) and nonequilibrium (NE) modeling approaches may be appropriate for describing…”
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Analytical approximation of biodegradation rate for in situ bioremediation of groundwater under ideal radial flow conditions by Oya, Shunji, Valocchi, Albert J.

“…We derive the long-term biodegradation rate of an organic contaminant (substrate) for an in situ bioremediation model with axisymmetric flow conditions. The…”
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Application of a reactive transport model for interpreting non-conservative tracer experiments: The Rio Maior case-study by Leitão, Teresa E., Lobo-Ferreira, J.P., Valocchi, Albert J.

“…The application of analytical groundwater solute transport models is presented in a case-study in the white-sand aquifer of Rio Maior, Portugal. Two…”
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