Coefficients of longitudinal and lateral dispersion were measured for steady uniform laminar flow through an isotropic porous medium. A unique experimental method for measuring lateral dispersion is described. It is found that the ratio of the coefficient of longitudinal dispersion D1 to the coefficient of lateral dispersion D2 is given by $\frac {D_1}{D_2} = \lambda \Re ^n$ where λ and n are dimensionless coefficients dependent upon the pore-system geometry, and [real ] is the Reynolds number based on the seepage velocity, the average grain diameter, and the kinematic viscosity.

Molecular diffusion is one of several phenomena contributing to establishment of rates of transfer of adsorbed materials from the exterior sites of a porous adsorbent to surfaces bounding inner pore spaces. For many applications of adsorption and ion exchange the rate of intraparticle transport in turn governs the over-all rate of removal of solute from solution. The present work represents an approach to partial characterization of intraparticle transport kinetics by separation and evaluation of component molecular diffusion parameters. Data have been collected for rates of adsorption in several dilute, aqueous, single-solute experimental systems, each comprised of a linear-chain sulfonated alkylbenzene in micromolar concentration as the adsorbate and porous granular carbon as the absorbent. From measurements of rate of removal of solute from bulk solution for each system, and from separate measurements of adsorption isotherms, values for the corresponding coefficients of molecular diffusion have been calculated by numerical integration of the conservation of diffusing mass equation, incorporating an expression for simultaneous adsorption according to the nonlinear Langmuir monolayer model for adsorption. Calculated values for the coefficients of diffusion for the respective solutes, of the order of 10-•-10 -7 square centimeter per second, derived from measurements in the experimental systems, agree with values cited in the literature for the same and similar solutes measured in aqueous solution. This accordance indicates that the postulated model for intraparticle transport may be valid for description of the rate-limiting process in agitated nonflow systems similar to those from which the experimental data have been derived. The technique further permits reduction of experimental data to a common parameter to facilitate system-to-system comparisons. NOMENCLATURE r, A, area of solution served by a unit length of a particle of adsorbent. S, a, radius of a cylindrical particle of adsorbent. S•, b, constant, expressive of energy of adsorption. s, C, concentration of diffusing solute; concen-T, tration of solute in solution. t, initial concentration of solute in solution. Vm, diffusion coefficient. z, diameter of cylindrical particle of ad-• sotbent. f],

The aim of this investigation was to determine the shape and the position of the interface between the seaward flowing fresh water and the underlying salt water in both the isotropic and nonhomogeneous and the anisotropic and nonhomogeneous coastal aquifers. A transformation for the nonharmonic anisotropic layer was introduced so that the governing equations and boundary conditions in the complex potential plane were satisfied. For the nonhomogeneous layers,. the homogeneous mathematical models were superimposed under the same dynamical conditions. Solutions of the flow patterns and interface locations have been presented in dimensionless form. It was assumed that the aquifers were anisotropic or nonhomogeneous only in the two-dimensional sense. From earlier studies it has been shown that the solutions obtained are valid for both the confined aquifer and the unconfined aquifer when the length of salt intrusion is greater than the depth of the aquifer. 1235 1236 RUMER AND SI-IIALT

A distorted hydraulic model of Lake Ontario has been constructed and operated in a rotating laboratory.The model study includes the cffccts of the earth's rotation, gravity, and hydraulic through-flow. Boundary shear in the model was checked against theoretical predictions of scichc decay. Wind shear was adjusted to achieve appropriately scaled drift velocities in the model. Observed surface and subsurface circulation patterns are presented for a homogeneous and stratified lake model with and without a westerly wind.

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