TERMIUM Plus^®

Fiche 1,  Justifications,  Anglais

Record number: 1, Textual support number: 1 DEF

Phenomenon which arises as a result of the build-up of a layer of rejected solute at the membrane surface which impedes solvent flow. The resistance to flow due to this layer thus increases until a point is reached where the rate of diffusion of solute away from the polarization layer equals the rate of deposition. This phenomenon also explains why the solvent flux often becomes invariant with an increasing transmembrane pressure drop. Although solvent flux through a membrane is a hydraulic pressure-activated process and should increase with increasing pressure, a point is reached where the rate of build-up of the solute polarization layer is such that flow is impeded and further increases in pressure have no effect.  2, fiche 1, Anglais, - concentration%20polarization

Record number: 1, Textual support number: 1 CONT

Concentration is the only important application with regard to initial enzyme recovery. Coarse fractionation is rarely attempted on a large scale, mainly because concentration polarisation ... occurs during ultra-filtration, effectively preventing an adequate separation. Equally, removal of salts and low molecular weight species alone is not the prime consideration, although ultrafiltration is commonly used to this end later in enzyme purification processes.  4, fiche 1, Anglais, - concentration%20polarization

Fiche 1,  Justifications,  Français

Record number: 1, Textual support number: 1 CONT

Grâce à leurs propriétés plastiques, les supports membranaires peuvent équiper des réacteurs de conceptions technologiques très diverses. Dans certains cas, la membrane constitue une simple barrière physique retenant les macromolécules dans le compartiment réactionnel : c'est le principe des membranes d'ultrafiltration utilisées pour récupérer le biocatalyseur dans les réacteurs agités. [...] Le principal inconvénient de cette technique est le phénomène de "polarisation" qui se traduit par une accumulation des composés de haut poids moléculaire sur la face amont de la membrane et un colmatage des pores.  2, fiche 1, Français, - polarisation

Fiche 1,  Justifications,  Espagnol

Fiche 2,  Justifications,  Anglais

Record number: 2, Textual support number: 1 OBS

Electrolytic conduction is the predominating factor in most rocks (...), being the only form of conduction when no minerals are present and the frequency is low. Thus a rock structure must be somewhat porous to permit current flow when metallic minerals are absent. Most rock minerals have a net negative charge at the interface between the rock surface and pore fluid. Consequently positive ions are attracted towards, negative repelled from, this interface; (...)  1, fiche 2, Anglais, - membrane%20polarization

Fiche 2,  Justifications,  Français

Record number: 2, Textual support number: 1 OBS

La séparation des charges positives et négatives entre des minéraux de différentes conductivités électriques résulte en une concentration des charges en surface des grains mais pas à l'intérieur. La polarisation des interfaces est effective dans la région des basses fréquences.  1, fiche 2, Français, - polarisation%20des%20interfaces%20des%20grains%20ou%20cristaux

Fiche 2,  Justifications,  Espagnol