In this study, friction stir welding (FSW) of commercially pure aluminium is carried out. The main defects existing in this process are cavity, irregular material flow due to unsuitable selection of welding parameters. In this study, to reduce the defects by selecting suitable parameter and welding quality determined by mechanical testing methods and non-destructive testing methods. Welding is done with preheating the base metals and without preheating the base metals and their effects are analyzed with similar parameter. The parameters considered for this work are spindle rotational speed (rpm), tool travel speed (mm/min) and axial force (kN). The experimental results are evaluated by Destructive Test and Nondestructive test methods. The characterization study is performed by Optical microscope and Scanning Electron microscopy (SEM).

Combustion characteristics of a fuel defines its performance and emission characteristics. Enhancement of combustion characteristics is feasible by improvisation of fuel properties. Fuel additives were used for varying fuel properties. The evolution of ‘nano-concept’ develops countless applications in the existing technologies. In this experiment silicon nanoparticles were synthesized by ball milling micron sized silicon particles for 45 hours. The elemental and structural characterizations for the additive material were carried out by EDS, SEM and TEM analysis. Silicon nano additive was mixed in three different weight proportions with diesel to prepare the test fuels. The fuel properties variation with the addition of nano additive were studied. Engine testing was carried out at constant 1200 rpm speed and varying load conditions. Diesel fuel added with 0.5 wt% Si nanoadditive (Si 0.5) showed maximum load carrying ability among the different test fuels. In comparison with diesel at 1200 rpm and 100% load condition, an increase in torque of 5.91% was observed and BTE was increased by 8.93% with a decrease in NOx emission by 27.3%. Variation in the performance and emission characteristics of the fuels were the results of change in heat release rate and combustion timing with the addition of nano additives which could be studied from the combustion characteristic curves.