The study of diffusion in macromolecular solutions is important in many biomedical applications such as separations, drug delivery, and cell encapsulation, and key for many biological processes such as protein assembly and interstitial transport. Not surprisingly, multiple models for the a-priori prediction of diffusion in macromolecular environments have been proposed. However, most models inc...

Two dimensionless parameters, the diffusional Deborah number, De, and the swelling interface number, Sw, were used as indicators of solvent and solute transport behavior in swellable hydrogel systems. Polymer relaxation and concentration-dependent diffusion led to dynamically swelling polymers which displayed Fickian, Case II, or anomalous transport behavior. Experimental systems studied includ...

INTRODUCTION: Solute transport within the intervertebral disc is critical for the disc functions. Small molecular-weight solutes, such as glucose, lactate and oxygen, are the components of the nutrient supply and the metabolic waste removal. Molecular weight of enzymes and chemical drugs for the disc therapy are usually within the order of thousands of Dalton. Larger solutes such as cytokines (...

This paper proposes groundwater flow simulation models based on explicit finite difference method (FDFLOW) and Galerkin finite element method (FEFLOW) and solute transport simulation models based on Galerkin finite element method (FESOLUTE), random walk method (RWSOLUTE) and modified method of characteristic (MMOCSOLUTE). These coupled flow and transport models are aimed at simulation of solute...

It is widely recognized that groundwater flow and solute transport in natural media are largely controlled by heterogeneities. In the last three decades, many studies have examined the effects of heterogeneous hydraulic conductivity fields on flow and transport processes, but there has been much less attention to the influence of heterogeneous porosity fields. In this study, we use porosity and...

BACKGROUND Patients on peritoneal dialysis (PD) with high small solute peritoneal membrane transport have an increased risk of morbidity and mortality. The membrane transport is currently assessed by peritoneal equilibration test (PET), usually performed after the first month of PD because of the early increase of membrane transport after the start of PD. The aim of this study was the assessmen...

Groundwater age distributions are used to estimate the parameters of Fickian, and non-Fickian, effective models of solute transport. Based on the similarities between the transport and age equations, we develop a deconvolution based approach that describes transport between two monitoring wells. We show that the proposed method gives exact estimates of the travel time distribution between two w...

The question of whether or not soil hydraulic parameters of dualpermeability models (DPM) can be properly identified by inverse analysis of preferential water flow data has not been resolved to date. We applied a DPM based on two coupled Richards’ equations to compare the performance of inverse and forward simulations of laboratory preferential flow data. Infiltration and drainage experiments w...

Previous studies of hyporheic zone focused largely on the net mass transfer of solutes between stream and streambed. Solute transport processes within the bed has attracted less investigation. In this study, we combined flume experiments and numerical simulations to examine solute transport processes in a streambed with periodic bedforms. Solute originating from the stream was subjected to adve...

The transport of solutes and colloids in porous media is influenced by a variety of physical and chemical nonequilibrium processes. A combined physical-chemical nonequilibrium (PCNE) model was therefore used to describe general mass transport. The model partitions the pore space into "mobile" and "immobile" flow regions with first-order mass transfer between these two regions (i.e, "physical" n...