A global nonlinear stability analysis is performed for a couple-stress fluid layer heated from below saturating a porous medium with temperature-pressure dependent viscosity for different conducting boundary systems. Here, the global nonlinear stability threshold for convection is exactly the same as the linear instability boundary. This optimal result is important because it shows that lineari...

Change in the permeability of the mitochondrial membrane to proteins (cytochrome c and Smac) and protons is a critical step in apoptosis. Although the time from the induction of apoptosis to the change of mitochondrial permeability is variable over a period of hours, the release of proteins is an "all or none" phenomenon that is completed in an individual cell within minutes. Here, using single...

Alcohol consumption leads to the production of the highly reactive ethanol metabolite, acetaldehyde, which may affect intestinal tight junctions and increase paracellular permeability. We examined the effects of elevated acetaldehyde within the gastrointestinal tract on the permeability and bioavailability of hydrophilic markers and drug molecules of variable molecular weight and geometry. In v...

Hillslope scale runoff is generated as a result of interacting factors that include water influx rate, surface and subsurface properties, and antecedent saturation. Heterogeneity of these factors affects the existence and characteristics of runoff. This heterogeneity becomes an increasingly relevant consideration as hydrologic models are extended and employed to capture greater detail in runoff...

Permeability is an important parameter in the process of coalbed methane exploitation. To improve production efficiency and explore control mechanism gas flow law coal, permeability helium nitrogen same coal sample was tested under different effective stress (the difference between external pore pressure mass) by using seepage device. Based on theory, interaction stress, adsorption effect Klink...

BACKGROUND The aim of the present study was to analyze variations in permeability of albumin and immunoglobulin G (IgG) influx into cerebrospinal fluid (CSF) in a clinical setting. METHODS In a retrospective intra-individual comparison of CSF samples, we used the IgGIndex and its constituents to indicate alterations in IgG/albumin permeability. RESULTS We found altered IgGIndices in 25/64 p...

A new method for the determination of permeability fields in highly heterogeneous aquifers is proposed. It stems from the known relations between soil electric resistivity and permeability. Several cut-offs are made to electric resistivity probability distribution. These cut-offs are heuristic estimates about what classes of values of one variable should relate to what classes of values of the ...

The commonly used British Standard constant head triaxial permeability test for testing of finegrained soils is relatively time consuming. A reduction in the required time for soil permeability testing would provide potential cost savings to the construction industry, particularly in the construction quality assurance of landfill clay liners. The purpose of this paper is to evaluate an alternat...