Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0851184 (thinning)
 11,252 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The creaming and rheology of fine n-tetradecane oil-in-water emulsions at pH 6.8 containing the commercial protein sodium caseinate and the ionic surfactant sodium dodecyl sulfate (SDS) have been studied, and an overview diagram relating surfactant composition and creaming stability has been constructed. The presence of both SDS and sodium caseinate in an emulsion system increases the overall stability with respect to creaming. Excess SDS promotes destabilization through fast creaming; this can be attributed to depletion flocculation brought about by unadsorbed surfactant micelles. Addition of sodium caseinate was found to reduce this effect, even at relatively high SDS concentrations. The behavior of the caseinate + SDS emulsions is thus different from the behavior of the previously reported caseinate + Tween 20 systems, where the combination of the two surface-active agents was found to reduce the emulsion stability, as indicated by fast creaming and shear-thinning rheology. Addition of sodium chloride was found to increase the extent of non-Newtonian behavior and to enhance the degree of creaming for SDS-containing emulsions. Increased caseinate levels in these systems seem to offer some stabilization through reduction of the shear-thinning character and improvement in creaming stability. These phenomena can be explained in terms of a considerable amount of SDS binding to the protein, which reduces the amount of SDS available to promote protein displacement and depletion flocculation. In contrast to the SDS systems, the properties of equivalent emulsions containing caseinate + nonionic surfactant Tween 20 are relatively insensitive to salt content. Copyright 2000 Academic Press.
 ...
PMID:Creaming and Rheology of Oil-in-Water Emulsions Containing Sodium Dodecyl Sulfate and Sodium Caseinate. 1070 4

The present study reports experimental data and scaling analysis for forced convection of foams and microfoams in laminar flow in circular and rectangular tubes as well as in tube bundles. Foams and microfoams are pseudoplastic (shear thinning) two-phase fluids consisting of tightly packed bubbles with diameters ranging from tens of microns to a few millimeters. They have found applications in separation processes, soil remediation, oil recovery, water treatment, food processes, as well as in fire fighting and in heat exchangers. First, aqueous solutions of surfactant Tween 20 with different concentrations were used to generate microfoams with various porosity, bubble size distribution, and rheological behavior. These different microfoams were flowed in uniformly heated circular tubes of different diameter instrumented with thermocouples. A wide range of heat fluxes and flow rates were explored. Experimental data were compared with analytical and semi-empirical expressions derived and validated for single-phase power-law fluids. These correlations were extended to two-phase foams by defining the Reynolds number based on the effective viscosity and density of microfoams. However, the local Nusselt and Prandtl numbers were defined based on the specific heat and thermal conductivity of water. Indeed, the heated wall was continuously in contact with a film of water controlling convective heat transfer to the microfoams. Overall, good agreement between experimental results and model predictions was obtained for all experimental conditions considered. Finally, the same approach was shown to be also valid for experimental data reported in the literature for laminar forced convection of microfoams in rectangular minichannels and of macrofoams across aligned and staggered tube bundles with constant wall heat flux.
 ...
PMID:Convective heat transfer in foams under laminar flow in pipes and tube bundles. 2555 45