Majid Moosavi - Dept. of Chemistry, Ferdowsi University of Mashhad, Mashhad ۹۱۷۷۹, Iran
Elaheh K. Goharshadi - Dept. of Chemistry, Ferdowsi University of Mashhad, Mashhad ۹۱۷۷۹, Iran. Center of Nano Research, Ferdowsi University of Mashhad, Iran
Abbas Youssefi - Par-e-Taavous Research Institute, Mashhad, Iran

Nanofluids are a new kind of fluids containing a very small quantity of nanoparticles that are uniformly and stably suspended in a liquid. Choi [1] coined the term nanofluids for this new class of solid/liquid suspensions, developed primarily for heat transfer applications. The impact of nanofluid technology is expected to be significant, considering heat transfer performance is vital in numerous multibillion dollar industries. Nanofluid technology willthus be an exciting new technology of 21st century. Thermal conductivity of traditional heat transfer fluids such as lubricants, engines coolants, and water are inherently low. Metals and metal oxides in solid form have orders-of-magnitude higher thermal conductivities than those of fluids. The thermal conductivity of fluids that contain suspended solid metallic particles could be significantly higher than that of conventional heat transferfluids. Undoubtedly, the most important property of nanofluids is thermal conductivity. A large number of investigations have been reported for thermal conductivity of different nanofluids [2-4] but just a little work has been made on other properties such as viscosity [5,6] and surface tension of nanofluids. The use of nanofluids in other applications is under developing, for example, some nanofluids such as TiO2 and ZnO can be also used as antibacterial media [7,8].