A common barrier to accurately predicting the fate of reactive contaminants is accurately describing the role of incomplete mixing. In this paper we develop a stochastic analytical framework for an irreversible kinetic bimolecular reaction in a system with anomalous transport, governed by the fractional advection– dispersion equation (fADE). The classical well-mixed (thermodynamic) solution dic...

determination of the best method to estimate the dispersion rate is very important to ensure accuracy of the computed data. the aim of this research is studying of transport length effects of dispersion of conservative tracer nacl in soils with different texture using several solute transport models including brigham, fried-combernous and solutions of the advection-dispersion equation with inve...

This paper deals with data reconstruction problem for a real disturbed soil-column experiment using an optimal perturbation regularization algorithm. A purpose of doing the experiment is to simulate and study transport behaviors of Ca2 , Na , Mg2 , K , SO 2− 4 , NO − 3 , HCO − 3 , and Cl − when they vertically penetrating through sandy soils. By data analysis to breakthrough data of the eight k...

The forward Fractional Advection Dispersion Equation (FADE) provides a useful model for non-Fickian transport in heterogeneous porous media. The space FADE captures the long leading tail, skewness, and fast spreading typically seen in concentration profiles from field data. This paper develops the corresponding backward FADE model, to identify source location and release time. The backward meth...

Mixing-transport of solute entering at sinkholes or from within the limestone matrix in cavernous conduits is an important process for contaminant migration in karst aquifers. This process may be described with a one-dimensional advection-dispersion equation incorporating the fluxes of solute and water across the conduit wall. For the dilution-dispersion equation, which does not include solute ...

We describe the continuous time random walk (CTRW) MATLAB toolbox, a collection of MATLAB scripts and functions that compute breakthrough curves (BTCs) and one-dimensional/two-dimensional (1D/2D) resident concentration profiles for passive tracer dispersion. The transport model is based on the CTRW theory. CTRW includes as special cases the classical Fickian dispersion based advection-dispersio...

Demand has increased for analytical solutions to determine the velocities and dispersion coefficients that describe solute transport with spatial, temporal, or spatiotemporal variations encountered in field. However, few have considered spatially, temporally, spatiotemporally dependent velocities. The proposed consider eight cases of velocities: both spatially dependent, temporally coefficient ...

The differential migration of ions in an applied electric field is the basis for separation of chemical species by capillary electrophoresis. Axial diffusion of the concentration peak limits the separation efficiency. Electromigration dispersion is observed when the concentration of sample ions is comparable to that of the background ions. Under such conditions, the local electrical conductivit...