3.2. THEORETICAL BACKGROUND OF PAMPA .................................................................................. 127 3.2.1. pH partition hypothesis ......................................................................................................... 128 3.2.2. The PAMPA assay ................................................................................................................

In this study, a chemical additive made by a combination of polymer, alkaline, and silica nanoparticles is used to control the oil recovery and relative permeability curves. Various parametersincluding the type and concentration of polymer, alkaline, and nanosilica particles have been studied.To evaluate the efficiency of these additives, we performed unsteady state displaceme...

A PEBAX-nano zeolite X mixed matrix membrane was fabricated and operationally characterized using single gas (CO2) permeation. X-ray diffraction (XRD) analysis was used to study the arrangement of polymer chains of mixed matrix membrane. The membranes were characterized by scanning electron microscopy (SEM) to study cross-sectional morphology. The single gas permeability were carried...

An efficient approach for the synthesis of norbuprenorphin derivatives through coupling of enkephalins and norbuprenorphine intermediate is described. Norbuprenorphine derivative was synthesized from thebaine and then, its reaction with succinic acid and phthalic acid was also studied. Meanwhile, the synthesis of enkephalins was done using solid phase peptide synthesis approach. Furthermore, af...

Gas reservoirs with low permeability (k<0.1 mD) are among the unconventional reservoirs and are commonly termed as "Tight Gas Reservoirs". In conventional gas reservoirs that have high permeability, the flow of gas is basically controlled by the reservoir permeability and it is calculated using the Darcy equation. In these reservoirs, gas flow due to gas diffusion is ignored compared to Dar...

[1] We report on laboratory experiments designed to investigate the influence of pore pressure oscillations on the effective permeability of fractured rock. Berea sandstone samples were fractured in situ under triaxial stresses of tens of megapascals, and deionized water was forced through the incipient fracture under conditions of steady and oscillating pore pressure. We find that short‐term p...

12 We report on laboratory experiments designed to investigate the effect of 13 dynamic stressing on permeability of fractured rock. Berea sandstone samples 14 were fractured in-situ under triaxial stresses of 10's of MPa, and deionized 15 water was forced through the incipient fracture under conditions of steady and 16 oscillating pore pressure. We find that dynamic stresses produced by pore 1...

Nystatin and amphotericin B increase the permeability of thin (<100 A) lipid membranes to ions, water, and nonelectrolytes. Water and nonelectrolyte permeability increase linearly with membrane conductance (i.e., ion permeability). In the unmodified membrane, the osmotic permeability coefficient, P(f), is equal to the tagged water permeability coefficient, (P(d))(w); in the nystatin- or amphote...

Brain tumor-associated cerebral edema arises because tumor capillaries lack normal blood-brain barrier function; vascular permeability factor (VPF, also known as vascular endothelial growth factor, VEGF) is a likely mediator of this phenomenon. Clinically, dexamethasone reduces brain tumor-associated vascular permeability through poorly understood mechanisms. Our goals were to determine if supp...

BACKGROUND Long-term non-steroidal anti-inflammatory drug (NSAID) intake may induce increased intestinal permeability, eventually resulting in enteropathy. Because increased permeability might be related to cell damage resulting from energy depletion, it was hypothesized that glutamine--the major energy source of the intestinal mucosal cell--might prevent permeability changes. METHODS The 6-h...