Osmotic flow

In a detersive system containing a dilute surfactant solution and a substrate bearing a soHd polar sod, the first effect is adsorption of surfactant at the sod—bath interface. This adsorption is equivalent to the formation of a thin layer of relatively concentrated surfactant solution at the interface, which is continuously renewable and can penetrate the sod phase. Osmotic flow of water and the extmsion of myelin forms foHows the penetration, with ultimate formation of an equdibrium phase. This equdibrium phase may be microemulsion rather than Hquid crystalline, but in any event it is fluid and flushable... 

You should remember that RO uses a semi-permeable membrane. As such, the membrane is permeable to only very light molecules like water. Under atmospheric condirtions the fresh water flows into the solution which is called osmotic flow. But for purification purposes, this is no use, and hence we employ the reverse of osmotic flow. For this to happen, we need to apply external pressure in excess of osmotic pressure. The osmotic pressure is given by ... 

J. L. Anderson, D. M. Malone. Mechanisms of osmotic flow in porous membranes transport. Biophys 14 951, 1974. 

Total Salinity. The salinity control of oil-base mud is very important for stabilizing water-sensitive shales and clays. Depending upon the ionic concentration of the shale waters and of the mud water phase, an osmotic flow of pure water from the weaker salt concentration (in shale) to the stronger salt concentration (in mud) will occur. This may cause a dehydration of the shale and, consequently, affect its stabilization. 

In isotonic solution, red blood cells are spherical top). At higher ion concentration center), osmotic flow removes water from the cell interior, shrinking the cell. At lower ion concentration, osmotic flow pumps water into the cell and may cause it to burst bottom). 

Capillary electrophoresis (CE) has several unique advantages compared to HPLC, snch as higher efficiency dne to non-parabolic fronting, shorter analytical time, prodnction of no or much smaller amounts of organic solvents, and lower cost for capillary zone electrophoresis (CZE) and fused-silica capillary techniques. However, in CZE, the most popular separation mode for CE, the analytes are separated on the basis of differences in charge and molecular sizes, and therefore neutral compounds snch as carotenoids do not migrate and all co-elute with the electro-osmotic flow. 

Figure 2.47 Micro mixer based on the excitation of an electro-osmotic flow around a cylinder by an oscillatory electric field (top). The bottom of the figure shows particle traces on both sides of the liquid/liquid interface with no electric field (above) and with the electric field switched on (below), as described in [145].

Top plate material Polydimethyl-siloxane (PDMS) Tube for electro-osmotic flow inner diameter length 500 pm 20 mm... 

Table 2 Additives Frequently Used in HPCE for Electro-osmotic Flow (EOF) Modification...

Tsuda, T., Modification of electro-osmotic flow with cetyltrimethylammonium bromide in capillary zone electrophoresis, /. High Resolut. Chromatogr., 10,622, 1987. 

Landers, J. P., Oda, R. P., Madden, B. J., and Spelsberg, T. C., High-performance capillary electrophoresis of glycoproteins the use of modifiers of electro-osmotic flow for analysis of microheterogeneity, Anal. Biochem., 205, 115, 1992. 

GM Zentner, GS Rork, KJ Himmelstein. Osmotic flow through controlled porosity films An approach to the delivery of water soluble compounds. In JM Anderson, SW Kim, eds. Advances in Drug Delivery Systems. New York Elsevier, 1986, pp 217-230. 

Differential solute migration superimposed on electro-osmotic flow in... 

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