This work employed numerical experiments simulating colloid and solute transport in single parallel-plate fractures, using the random walk particle tracking method, to demonstrate that (1) there exists an aspect ratio of the colloid radius to half the fracture aperture, delta(o), where the average velocities of colloids and solutes are similar. When delta>delta(o), the velocity distribution ass...

The food-borne pathogen Listeria monocytogenes proliferates at refrigeration temperatures, rendering refrigeration ineffective in the preservation of Listeria-contaminated foods. The uptake and intracellular accumulation of the potent compatible solutes glycine betaine and carnitine has been shown to be a key mediator of the pathogen's cold-tolerant phenotype. To date, three compatible solute s...

Methanogenic Archaea are found in a wide range of environments and use several strategies to adjust to changes in extracellular solute concentrations. One methanogenic archaeon, Methanosarcina thermophila TM-1, can adapt to various osmotic conditions by synthesis of alpha-glutamate and a newly discovered compatible solute, Ne-acetyl-beta-lysine, or by accumulation of glycine betaine (betaine) a...

In this paper we formulate a system of partial diierential equations that models the contamination of groundwater due to migration of dissolved contaminants through unsaturated to saturated zone. A closed form solution using singular perturbation techniques for the water ow and solute transport equations in the unsaturated zone is given. Indeed, the solution can be used as a tools to verify the...

It has been recognized that matrix diffusion is an important process for retarding solute transport in fractured rock. Based on analyses of tracer transport data from a number of field tests, we demonstrate that the effective matrix-diffusion coefficient may be scaledependent and generally increases with test scale. A preliminary theoretical explanation of this scale dependency is also presente...

Perfusion studies were performed in healthy volunteers to test the hypothesis that net fluid secretion induced by fatty acids is accompanied by parallel reduction in solute transport. Ricinoleic acid provoked a marked net secretion of fluid and concomitantly inhibited the absorption of all solutes tested; these included glucose, xylose, L-leucine, L-lysine, Folic acid, and 2-mono-olein. Oleic a...

Perfusion studies were performed in healthy volunteers to test the hypothesis that net fluid secretion induced by fatty acids is accompanied by parallel reduction in solute transport. Ricinoleic acid provoked a marked net secretion of fluid and concomitantly inhibited the absorption of all solutes tested; these included glucose, xylose, L-leucine, L-lysine, folic acid, and 2-mono-olein. Oleic a...

The permeability of frog skin under the influence of urea hyperosmolarity has been studied. Flux ratio asymmetry has been demonstrated again for tracer mannitol. The inhibitors DNP, CN(-), and ouabain have been used to eliminate active sodium transport and it was found that urea hyperosmolarity produces asymmetrical mannitol fluxes on frog skins having no short-circuit current. These findings s...

The present work solves two-dimensional Advection-Dispersion Equation (ADE) in a semi-infinite domain. A variable source concentration is regarded as the monotonic decreasing function at the source boundary (x=0). Depth-dependent variables are considered to incorporate real life situations in this modeling study, with zero flux condition assumed to occur at the exit boundary of the domain, i.e....

Hydrodynamic dispersion is an important factor controlling contaminant migration in the subsurface environment. However, few comprehensive data sets exist for evaluating the impact of travel distance and site heterogeneity on solute dispersion under non-uniform flow conditions. In addition, anionic tracers are often used to estimate physical transport parameters based on an erroneous assumption...