OICC Press Journal of Nanostructure in Chemistry 2193-8865 3 1 (December 2013) 2013 05 03 The effect of silver and aluminum oxide nanoparticles on thermophysical properties of nanofluids 10.1186/2193-8865-3-28 EN Heydar Maddah Shahrood Branch, Islamic Azad University, Shahrood, 3619995161, IR Mahdokht Rezazadeh Young Research Club, Saveh Branch, Islamic Azad University, Saveh, 39187/366, IR Mojtaba Maghsoudi Sama-Saveh Branch, Islamic Azad University, Saveh, 39187/366, IR Syamak NasiriKokhdan Kashan University, Kashan, 87314, IR Journal Article 2013 05 03 Abstract The present paper describes experimental and theoretical aspects of the effective thermal conductivity, electrical conductivity, and viscosity of nanofluids. The thermal conductivity, electrical conductivity, and viscosity of nanofluids increase with the nanoparticle volume fraction. The nanofluid was prepared by synthesizing Al 2 O 3 and Ag nanoparticles using microwave-assisted chemical precipitation method and then dispersed in distilled water using a sonicator. Water nanofluid with nominal diameters of 20 and 40 nm at various volume concentrations (0.25% to 5%) at a temperature of 15°C was used for the investigation. The thermal conductivity, electrical conductivity, and viscosity of nanofluids were measured, and it was found that the viscosity and electrical conductivity increase is substantially higher than the increase in thermal conductivity. The pure base fluid thermal conductivity displayed a Newtonian behavior at 15°C; it transformed to a non-Newtonian fluid with the addition of a small amount of nanoparticles φ > 3%.