Using Al2O3 nanoparticles, de-ionized water, and different volume fractions of two surfactants, Al2O3/water nanofluids were prepared by a two-step method. Thermal conductivities of the nanofluids were measured by the thermal constants analyzer. The choice of surfactant used (either sodium dodecyl sulfate (SDS) or polyvinylpyrrolidone (PVP)) had an influence on the thermal and mechanical properties of the nanofluids. PVP was found to be better at stabilizing the nanofluid, ...