Membrane rheology

Tubular membranes of 8 long were prepared from blend composition consisting of CA and PMMA and performance data for one month operation was collected. These datas show high product water flux (18-20 gfd.) with low flux decline slope. However, it was observed that these membranes initially showed fountains" which disappeared in about 30 minutes time. This was attributed to the peculiar membrane rheology and orientation of PMMA molecule with respect to CA molecule. This needed further study for confirmation. 

A different mechanism should account for the antioxidant ability of hydrophobic flavonoids, which can be incorporated into the bilayer where they can affect certain membrane physical properties. It is well-known that alterations in membrane rheology will affect the extension and rate of lipid oxidation. For example, increased lipid oxidation rates have been observed... 

The properties of ordered structures in block copolymer melts have yet to be fully exploited, but the structural and rheological anisotropy is likely to lead to applications not all of which can be envisaged yet. The precision self-assembly of block copolymers into ordered structures for thin film and interfacial applications has enormous potential. Other applications such as nanoscale templates, membranes and filters could exploit the self-assembly of block copolymers into domains with periods 10-100 nm. The possibilities are limited only by the molecular engineer s imagination. 

Chronic diseases include cystic fibrosis in which nasal mucus is thick and viscous as a result of abnormal chloride transport across the membrane of the epithelial cells, leading to reduced water secretion. Similarly, chronic sinusitis also reduces nasal mucociliary clearance due to an increase in the rheological properties of mucus. 

Change in rheologic properties of biological membrane due to mucolytic action... 

The parison is inflated fast, within seconds or less, at a predetermined rate such that it does not burst while expanding. It is a complex process that involves expansion of a nonuniform membrane-like element. Because the extension ratio is high (above 10), it is difficult to calculate the final thickness distribution. Naturally, much of the recent theoretical research on parison stretching and inflation (as in the case with thermoforming) focuses on FEM methods and the selection of the appropriate rheological constitutive models to predict parison shape, thickness, and temperature distribution during the inflation. 

Interaction between double layers, one of the building bricks of colloid stability, is an important theme planned for Volume IV. It has a large number of spin-offs, in, for instance ion exchange, thin wetting films, free films, membranes, association colloids, vesicles, polyelectroljdes, emulsions and rheology. The dramatic influence of electroljrtes on these phenomena finds its origin in the changes in the double layer, discussed in this chapter. 

Parallel-plate perfusion system have been also useful to evaluate the relative roles of purified plasma adhesive proteins or isolated components of the vessel wall. Receptors for all fiiese proteins are present in the membrane of platelets. Potentially, platelets can adhere to all of them, although this ability does not depend exclusively on the recognition of the q>ecific proteins by its receptor but also on rheological factors. In fact, there may be more one receptor for each of the adhesive proteins. Recognition by one or another receptor may also be affected by the presence of divalent cations and by the degree of platelet activation. The use of the parallel-plate perfusion chamber together with manipulation of the perfusates and variations in experimental conditions allow the detailed study of basic pathophysiological mechanisms involved in platelet-vessel interactions. 

Young T-H and Chen L-W. Pore formation mechanism of membranes from phase inversion process. Desalination 1995 103(3) 233-247. Han M-J and Nam S-T. Thermodynamic and rheological variation in polysulfone solution by PVP and its effect in the preparation of phase inversion membrane. J. Membr. Sci. 2002 202(l-2) 55-61. 

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