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. ...

rheological characteristics of al2o3, cuo and tio2 nano particles were investigated in oil asthe base fluid at 1 and 2 wt.%. constitutive relations for non-newtonian fluid were discussedbased on the power-law model. measured viscosities of each nanofluid were used to evaluatethe power-law and consistency index. results indicated that the nanofluid viscosity decreasedby increasing the concentrat...

density, viscosity and refractive index of pure, binary and ternary mixtures of diethanolamine (dea) and methyl diethanolamine (mdea) with water have been measured at different temperatures from 288.15 k to 323.15 k at atmospheric pressure. also, this study presents the effects of mixture composition and temperature upon these thermo- physical properties. to measure the density and refractive i...

in this research, seeds of iranian carob trees grown wild in kazeroon city (fars province) were used to extract iranian locust bean gum as a seed galactomannan. chemical composition, solubility, and rheological properties of crude and purified gums were investigated and compared with a commercial (sigma) locust bean gum (lbg) sample. chemical composition of the purified iranian lbg was similar ...

Engine oils are widely used for lubrication purposes in automobile and related industries. Viscosity Index (VI) improver has found its largest commercial applications as additives to engine oils. Examples are power steering fluid, aircraft piston engine oils, modern internal-combustion engines, turbine engine oils (stationary and aircraft), and industrial gear oils. Viscosity Index improvers ar...

Rheological characteristics of Al2O3, CuO and TiO2 nano particles were investigated in oil asthe base fluid at 1 and 2 wt.%. Constitutive relations for non-Newtonian fluid were discussedbased on the power-law model. Measured viscosities of each nanofluid were used to evaluatethe power-law and consistency index. Results indicated that the nanofluid viscosity decreasedby increasing the concentrat...

in this study, effects of multi walled carbon nanotubes and temperature on rheological behavior of engine oil (10w40) have been examined. for this purpose, the experiments were carried out in the temperature range of 5-55°c for several suspensions with solid volume fractions of 0.025%, 0.05%, 0.1%, 0.25%, 0.5% and 0.75%. the viscosity of all samples was measured in the shear rate range of 666s-...

We examined whether hemorheology and platelet function are affected in essential hypertensives (EHTs) of the World Health Organization stage I when complicated with metabolic syndrome (Mets). In 156 untreated EHTs, blood viscosity and platelet surface markers were determined. Blood viscosity was significantly elevated in 54 subjects with Mets compared with 102 subjects without Mets. Hematocrit ...

Let M be a Lagrangian manifold, let the 1-form pdx be globally exact on M and let S(x, p) be defined by dS = pdx on M. Let H(x, p) be convex in p for all x and vanish on M . Let V (x) = inf{S(x, p) : p such that (x, p) ∈ M}. Recent work in the literature has shown that (i) V is a viscosity solution of H(x, ∂V/∂x) = 0 provided V is locally Lipschitz, and (ii) V is locally Lipschitz outside the s...

The present study attempted deriving and solving the falling- cylinder governing equations for power law model non-Newtonian fluids. Based on this theoretical study, a novel falling- cylinder rheometer (FCR) was designed and constructed to measure the Theological properties of non-Newtonian fluids. Different falling cylinders with predesigned densities were used to determine the apparent viscos...