nowdays, production of high quality engine oils is one of the worries of our country’s engine oil industry. in this study, the behavior of four commercial polymers used in nation motor oil industry in obtaining the best viscosity index improver was investigated. in this regard, viscometric behavior, shear stability and polymers’ performance for engine cranking were compared at low temperature. ...

flow characteristics and rheological parameters of “malas yazdi” pomegranate (punica granatum l.) juice were investigated using rotational viscometer at different temperatures (10, 20, 30, 40, 50, 60 and 70ºc) and concentrations (12, 22, 32, 42 and 52º brix). the experimental data had the best fitness with herschel-bulkley model and the values of flow behavior index (n) varied between 0.97 and ...

The subject of angular momentum transport is important in theories concerning accretion disks. The αmodel of Shakura and Sunyaev1) assumes outward transportation of angular momentum due to some viscous force. This viscosity is believed to originate from turbulence, because the molecular viscosity is far too small in this case. Because the viscosity formula for turbulence is not well known, gene...

Nearly all these materials have a viscosity that drops at higher rates of shear velocity resp, stress. This is the phenomenon of shear thinning which becomes progressively larger as the volume concentration of solid particles increases. At high concentration of solid content, the low shear rate viscosity region disappears completely, the material is yielding. Some materials show after the shear...

PURPOSE Artificial tear formulations typically contain a water-soluble polymer to enhance residence time, moisture retention, and binding to the mucin coat of the ocular surface, which facilitate corneal healing. This study investigated the potential advantages of combining carboxymethylcellulose (CMC) and hyaluronic acid (HA) polymers in a single formulation. MATERIALS AND METHODS Individual...

To evaluate the change of hemorheological indexes for patients with Alzheimer's disease (AD) at the early stages and to discuss effects of these changes on AD, high shear value of whole blood viscosity (etabh), reduced high shear value of whole blood viscosity (retabh), low shear value of whole blood viscosity (etabl), reduced low shear, value of whole blood viscosity (retabl), KT value of whol...

We measured the coefficients of viscosity, shear rates and shear stresses of chicken small intestinal and caecal contents, including solid particles, using a tube-flow viscometer. The coefficients of viscosity of chicken small intestinal and caecal contents were correlated negatively with their shear rates, a characteristic typical of non-Newtonian fluids. The coefficient of viscosity of the sm...

A non-Brownian suspension of micron scale rods exhibits reversible shear-driven formation of disordered aggregates resulting in dramatic viscosity enhancement at low shear rates. Aggregate formation is imaged using a combined rheometer and fluorescence microscope. The size and structure of these aggregates are found to be a function of shear rate and concentration, with larger aggregates presen...