We study the Darcy problem with log-normal permeability, modeling the fluid flow in a heterogeneous porous medium. A perturbation approach is adopted, expanding the solution in Taylor series around the nominal value of the permeability. The resulting recursive deterministic problem satisfied by the expected value of the stochastic solution, analytically derived and studied in [4], is discretize...

Steady, Darcian, 1-D, 1-phase evaporation through a vertically inhomogeneous soil from a horizontal water table is simulated as an optimal control problem, i.e. the hydraulic properties of the porous medium (relative permeability of moisture and capillary water retention curve) are considered as control functions. The Richards nonlinear ordinary differential equation is integrated twice as a bo...

REPORTRAPPORT Entropy conditions for heterogeneity induced shocks in two-phase flow problems Abstract We study two-phase ow in a porous medium with piecewise smooth permeability. If capillary forces can not be neglected, the ow problem is parabolic. Without capillary forces this problem degenerates to a hyperbolic conservation law with a discontinuous ux function. The solution for this problem ...

We report the design and experimental measurement of a powered active magnetic metamaterial with tunable permeability. The unit cell is based on the combination of an embedded radiofrequency amplifier and a tunable phase shifter, which together control the response of the medium. The measurements show that a negative permeability metamaterial with zero loss or even gain can be achieved through ...

in this work a glass micromodel which its grains and pores are non-uniform in size, shape and distribution is considered as porous medium. a two-dimensional random network model of micromodel with non-uniform pores has been constructed. the non-uniformity of porous model is achieved by assigning parametric distribution functions to pores throat and pores length, which was measured using image a...

An in vitro model of the blood-brain barrier (BBB), consisting of porcine brain-derived microvascular endothelial cells (PBMEC), was used to evaluate the effect of astrocytes in the BBB disruption during hypoxia. Hypoxia-induced hyperpermeability was decreased significantly in a coculture model of astroglia cells, either astrocytes or C6 glioma cells, with PBMEC and, to the same extent, when gl...

Neurospora crassa conidia incubating in buffer at low water activities (a(w)) release a germination-essential component as well as 260-nm absorbing and ninhydrin-positive materials, regardless of whether an electrolyte or non-electrolyte is used to reduce a(w). Chloroform and antibiotics known to increase cell-membrane permeability have a similar effect. This suggests that membrane damage occur...

We present here the design of nano-inclusions made of properly arranged collections of plasmonic metallic nano-particles that may exhibit a resonant magnetic dipole collective response in the visible domain. When such inclusions are embedded in a host medium, they may provide metamaterials with negative effective permeability at optical frequencies. We also show how the same inclusions may prov...

The scope of this paper is to design and simulate a novel circular split ring structure having simultaneous negative permittivity and permeability so called double negative metamaterial or left handed material. The DNG structure consists of five circular split ring resonators on one side of dielectric medium and a couple of circular wires on other side. The complex permittivity, permeability, i...

The electrolytic conductance of living ceils has been used extensively as a measure of their permeability to electrolytes, and more particularly of the permeability of an hypothetical semipermeable plasma membrane supposed to delimit the protoplasm from the sur• rounding medium. There are, however, many possible sources of error in making such an interpretation, especially when suspensions of c...