We develop a model-based approach for studying the influence of polymers on drag reduction in a turbulent channel flow. Our simulation-free method utilizes turbulence modeling in conjunction with the analysis of stochastically forced linearized equations to capture the effect of velocity and polymer stress fluctuations on the turbulent viscosity and drag. We demonstrate that the essential drag-...

Plenty of natural polymers has been found effective to modulate the drug release. Numerous either alone or in combination with other were controlling In current study attempts made combine chitosan (degree deacetylation 88.42 %, Molecular weight 50,000 Da, and viscosity 93 CPS) HPMC K 15M retard release aceclofenac tablet formulation. The tablets prepared by wet granulation method evaluated for...

We suggest a model in which viscosity η is related to entropy of the system. The model successfully describes the dependence of viscosity on pressure. A master equation is developed that allows a comparison of data obtained at different temperatures. Earlier, in the framework of the same model we described the dependence of viscosity on temperature. The present treatment gives a simple interpre...

Replica molding of ultra-high-Q toroidal microresonators can produce polymer microresonators with material-limited quality factors (Q). This was demonstrated previously using polymers which cure thermally. In this work, high Q polymer microresonators were fabricated using the replica molding technique from previously uncharacterized polymers which require either a thermal or UV cure. The qualit...

background: the study of rheological properties of blood has special interest since it is a circulating fluid exposed to shear rates during its life time. this work aims to investigate the influence of whole body gamma irradiation on the rheological properties of rat’s blood. the applied shear rate was from 12 to 375 s-1. low shear viscosity (up to 100 s-1) depends mainly on the erythrocytes ag...

Measurements of the dynamic viscosity of various actin filament preparations under conditions of low and controlled shear: (a) confirm the shear rate dependence of F-actin viscosities and show that this dependence obeys the power law relationship observed for entangled synthetic polymers; (b) permit estimation of the extent to which shear artifact amplifies changes in the apparent viscosity of ...

Telechelic associating polymers (hydrophilic ethoxylated backbone, hydrophobic n-alkyl end-groups) form viscous solutions in water due to associations between the hydrophobes. The addition of alpha-, beta-, or gamma-cyclodextrin (CD) substantially reduces the solution viscosity because the CD molecules envelop and sequester the hydrophobes in their hydrophobic cavities. The present paper explor...

Polymerization and depolymerization of cytoskeletal elements maintaining cytoplasmic stiffness are key factors in the control of cell crawling. Rheometry is a significant tool in determining the mechanical properties of the single elements in vitro. Viscoelasticity of gels formed by these polymers strongly depends on both the length and the associations of the filaments (e.g. entanglements, ann...