m. eftekhar

Cobalt hydrogensulfate is an efficient catalyst for the condensation of β-naphthol, aromatic aldehydes and 5,5-dimethyl-1,3-cyclohexanedione at 120 °C to afford 9,9-dimethyl-12-phenyl-8,10,11,12-tetrahydro-9-H-benzo[a]xanthen-11-one derivatives in high yields. Also, polycondensation reactions of phenols with phthalic anhydride were carried out in the presence of cobalt hydrogensulphate under solvent-free conditions. Simple and convenient procedure, high conversion, reusability of catalyst, easy purification and short reaction time are the advantageous features of this method.

Running the industrial components at a proper temperature is always a big challenge for engineers. Internalcombustion engines are among these components in which temperature plays a big role in theirperformance and emissions. With the development of new technology in the fields of ‘nano-materials’ and‘nano-fluids’, it seems very promising to use this technology as a coolant in the internal combustionengines. In this study, a nano-fluid (Al2O3-Water/Ethylene Glycol (EG)) is used as an engine coolant alongwith an optimized heat exchanger to reduce the warm-up timing. The effect of nano-fluid concentration isconsidered here by using their corresponding governing equations, such as momentum and energy. Theengine coolant thermal behavior calculation is carried out based on the lumped method. The obtainedresults indicated that using different percentage of nano-fluid mixtures (by volume), such as Al2O3-Water/EG as engine coolant enhances the heat transfer coefficient and reduces the warm-up timing which,in turn, results in reduced emissions and fuel consumption.