A new formulation for shape and topology optimization in a Stokes flow is introduced. The investigated problem minimizes the total potential power of the flow. By combining a porous medium and a phase field approach we obtain a well-posed problem in a diffuse interface setting that can be reformulated into a problem without state equations. We can derive a sharp interface problem with zero perm...

Water flow in porous media is strongly controlled by the microscale structure of pore space. Therefore, understanding dynamics at scale fundamental to better estimate and describe hydraulic properties phenomena associated water which are observed a macroscale such as field or laboratory experiments. Pore geometry plays key role since its variations cause modifications behaviour macroscale. In t...

Black widow spider venom (BWSV) stimulates transmitter release and depletes synaptic vesicles from muscles bathed in a sodium free medium containing 1 mM EGTA. However, frog neuromuscular junctions treated with BWSV in glucosamine Ringer's and post-treated with antivenin recover normal function. This suggests that probably the permanent block of neuromuscular transmission is due to changes in p...

The Casimir effect is considered for a wedge with opening angle α, with perfectly conducting walls, when the interior region is filled with an isotropic and nondispersive medium with permittivity ǫ and permeability μ. The electromagnetic energy-momentum tensor in the bulk is calculated, together with the surface stress on the walls. A discussion is given on the possibilities for measuring the i...

The study of hydromagnetic unsteady MHD flow of an incompressible, electrically conducting, viscous fluid past an infinite vertical porous plate along with porous medium of time dependent permeability under oscillatory suction velocity normal to the plate has been made. It is considered that the influence of the uniform magnetic field acts normal to the flow and the permeability of the porous m...

The problem of the slow viscous flow of a fluid through a random porous medium is considered. The macroscopic Darcy’s law, which defines the fluid permeability k, is first derived in an ensemble-average formulation using the method of homogenization. The fluid permeability is given explicitly in terms of a random boundary-value problem. General variational principles, different to ones suggeste...

PURPOSE The functional characteristics of tight junctions in the outer blood-retinal barrier change during embryonic development and in the presence of disease. A culture model of developing retinal pigment epithelium (RPE) was used to examine the regulation of the tight junctions. METHODS RPE from chick embryos was cultured on filters that separated the apical and basal medium compartments. ...

Development of borehole geophysics has recently focused on reservoir characterization. Within this effort, extensive full waveform acoustic surveys have demonstrated a correlation between the occurance of open fractures and attenuation of Stoneley waves. A relationship is obtained here between fracture permeability and attenuation of Stoneley waves, on the basis of a physical mechanism. This me...

The nonhomogeneous gas or fluid flowing through a nonhomogeneous porous medium is studied. An interesting phenomenon is discussed which shows that the state of the flow is not affected by the surrounding environment if some hypotheses are made on the porosity of the gas, the viscosity, and the permeability of the medium. Such a state is called an isolated environment. The conditions under which...

We give uniqueness theorem and reconstruction algorithm for the nonlinearized problem of finding the dielectric anisotropy f of the medium from non-overdetermined polarization tomography data. We assume that the medium has uniform background parameters and that the anisotropic (dielectric permeability) perturbation is described by symmetric and sufficiently small matrix-function f . On a pure m...