[1] The transport of bromide, a conservative tracer, and rhodamine WT (RWT), a photodegrading tracer, was evaluated in three wastewater-dependent wetlands near Phoenix, Arizona, using a solute transport model with transient storage. Coupled sodium bromide and RWT tracer tests were performed to establish conservative transport and reactive parameters in constructed wetlands with water losses ran...

Time domain reflectometry (TDR) is rapidly becoming a popular method for measuring solute concentrations in the laboratory as well as in the field. Success or failure of TDR to represent solute resident concentrations depends on the accuracy of the invoked calibration. In this study, we compared three commonly used calibration methods that relate the impedance, Z+ as measured with TDR, to the s...

The ventilation of burrows by tube-dwelling benthos is understood to be important in determining rates of exchange of solutes between the sediment and overlying water. However, few models have attempted to link the burrow ventilation behavior of tube-dwelling organisms with their geochemical consequences. The classic cylinder model of bioirrigation in muddy sediments (Aller, R.C., 1980. Quantif...

Water and solute flux from the subsurface drains of macroporous agricultural fields are simulated using two-dimensional single-porosity and dual-porosity models. Field-averaged (i.e. effective) parameters are calibrated from drainage outflow and validated for water flow and the transport of non-reactive solutes applied at discrete locations on the field. Both the singleporosity and the dual-por...

The objectives of this study were to: (i) examine the efficacy of two sampling techniques for characterizing solute transport under steady-state water flow, (ii) study the variation in transport model parameters with increasing depth of solute leaching, and (iii) perform model discrimination to examine the transport process operative within a field plot. Bromide, NO?, and Clwere applied sequent...

A new model describing transport across lipid membrane was developed based on the Statistical Rate Theory (SRT) of interfacial transfer. In our calculations we replaced lipid membrane with well-defined octanol membrane. According to SRT the rate of solute transfer across water/octanol interface depends on the ratio of solute concentration in the both phases and the water/octanol partition coeff...

To determine whether solute transport across yeast membranes was facilitated, we measured the water and solute permeations of vacuole-derived and late secretory vesicles in Saccharomyces cerevisiae; all permeations were consistent with passive diffusive flow. We also overexpressed Fps1p, the putative glycerol facilitator in S. cerevisiae, in secretory vesicles but observed no effect on water, g...

subsurface drainage systems are used to control the depth of the water table and to reduce or prevent soil salinity. water flow in these systems is described by the boussinesq equation, and the advection-dispersion equation coupled with the boussinesq equation is used to study the solute transport. the objective of this study was to propose a finite difference solution of the advection-dispersi...

LASSITER, WILLIAM E., CARL W. GOTTSCHALK, AND MARGARET MYLLE. Micropuncture study of net transtubular movement of water and urea in nondiuretic mammalian kidney. Am. J. Physiol. 200(6) : I 139-I 146. I g6 I .-Anesthetized, nondiuretic rats and hamsters were infused with C14-labeled inulin-carboxylic acid or urea, and fluid was subsequently collected by micropuncture from surface tubules in the ...