The goal of this research was to define the controlling parameters affecting transport of drugs and proteins through poly(acrylic acid), PAA, and poly(acrylic acid-co-2-hydroxyethyl methacrylate), P(AA-co-HEMA). The hydrogel formulation variables investigated included the amount of crosslinking agent and non-ionizable comonomer (i.e. HEMA), which ultimately defined the mesh size available for s...

The role of high and low hydraulic conductivity (K) regions in heterogeneous flow fields with varying degrees of stratification and the subsequent effect of rate-dependent geochemical reactions is investigated. An example contamination scenario is used to to investigate potential impacts of kinetic sorption and local dispersion on plume migration and channeling. In this study, kinetic sorption ...

MOC3D is a general-purpose computer model developed by the U.S. Geological Survey (USGS) for simulation of three-dimensional solute transport in ground water (Konikow and others, 1996). The model is an update to the widely used USGS two-dimensional solutetransport model (MOC) and is implemented as an optional “package” for the ground-water flow model MODFLOW (Harbaugh and McDonald, 1996). Direc...

N. Toride, F. J. Leij, and M. Th. van Genuchten. The CXTFIT Code for Estimating Transport Parameters from Laboratory or Field Tracer Experiments, Version 2.0, Research Report No. 137, U. S. Salinity Laboratory, USDA, ARS, Riverside, CA. Successful predictions of the fate and transport of solutes in the subsurface hinges on the availability of accurate transport parameters. We modified and updat...

Researchers and practitioners alike often need to understand and characterize how water and solutes move through a stream in terms of the relative importance of in-stream and near-stream storage and transport processes. In-channel and subsurface storage processes are highly variable in space and time and difficult to measure. Storage estimates are commonly obtained using transient-storage model...

Fractured Gneiss aquifers present a challenge to hydrogeologists because of their geological complexity. Interpretation methods which can be applied to porous media cannot be applied to fractured Gneiss aquifers because flow and transport occur in fractures, joints, and conduits. In contrast, the rock matrix contribution to groundwater flow is not very important in Gneiss aquifers. Sodium chlor...

soil water retention curve is one of the crucial input parameters in any modeling study on water flow and solute transport in soils. direct measurement of soil water retention curve is time-consuming and costly. alternatively, pedotransfer functions (ptfs) may be used to indirectly estimate the soil water retention curve from easily measured soil properties. many equations for the soil water re...

The latent heat of fusion, L of the cryobiological media (a solute laden aqueous solution) is a crucial parameter in the cryopreservation process and has often been approximated to that of pure water ( 335 mJ=mgÞ. This study experimentally determines the magnitude and dynamics of latent heat during freezing of 14 different pre-nucleated solute laden aqueous systems using a differential scanning...

A fractal mobile-immobile (MIM in short) model for solute transport heterogeneous porous media is investigated from numerics. An implicit finite difference scheme set forth solving the coupled system, and stability convergence of are proved based on estimate spectral radius coefficient matrix. Numerical simulations with different parameters presented to reveal behaviors case.