The effect of compression ratio on combustion, performance, and emission characteristics of a direct injection single cylinder four stroke variable compression ratio multi fuel engine when fueled with corn oil methyl ester (COME) and palm oil methyl ester (POME) is investigated and compared with petroleum based diesel fuel (PBDF). The suitability of COME and POME as biofuels has been studied in this research. Biodiesels produced from corn oil and palm oil by transesterification process has been used in this study. Experiments were conducted at constant speed of 1500 rpm, full load, and at compression ratio of 17:1, 18:1, and 19:1. The effect of compression ratio on heat release rate, specific fuel consumption, and exhaust gas emissions has been investigated and presented. The fuels which gave best performance when used in engine have been identified by optimum compression ratio. The results indicate that shorter ignition delay, maximum rate of combustion pressure, and lower heat release rate at higher compression ratio were observed for POME when compared to PBDF. The brake thermal efficiency of POME was found to be maximum than PBDF at full load for all compression ratio. Exhaust gas temperature is low for biodiesels when compared to PBDF from compression ratio 17:1 to 19:1. The emission of CO, CO₂, and HC dropped with compression ratio 17:1 and it slightly increased when compression ratio is increased. The engine performance was found to be optimum when using POME as fuel, at compression ratio 19:1 during full load condition.

In this paper, the effect of gas tungsten arc welding (GTAW) parameters on the pitting corrosion on AISI 202 chromium manganese stainless steel was investigated. An empirical mathematical equation correlating pitting resistance equivalent number (PREN) with the welding parameters such as welding current, welding speed, welding gun angle and gas flow rate was developed. Central composite response surface methodology with four parameter and five levels was employed for conducting the experiments. The adequacy of the developed model was checked using ANOVA. The main effects of the process parameters on PREN of the welded joints were studied using surface and contour plots. The quality of the weld joint is also highly influenced by the microstructure of the weldment. The quality of the weldment gets deteriorated due to metallurgical changes such as micro-segregation, precipitation of secondary phases, presence of porosities, grain growth in the heat affected zone and loss of material by vaporization. This paper also investigates the influence of welding gun angle on the microstructure examination of the weldment. The microstructure study concentrated on the grain structure, presence of carbides and formation of ferrite, austenite and martensite in the weldment. The results obtained from the present investigation helps in quickly selecting the required process parameters to achieve the desired PREN and weld quality

The objective of this study is to investigate the effect of compression ratio on combustion characteristics of diesel engine with waste cooking oils methyl ester–diesel blends as fuel. The DI engine fuelled with Waste Cooking Rice Bran Methyl Ester (WCRBME) and Waste Cooking Cotton Seed Oil Methyl Ester (WCCSME) prepared by the transesterification process was investigated for its combustion and then compared with petroleum-based diesel fuel (PBDF). Experiments were conducted at a constant speed of 1500 rpm and maintained at a full-load condition for the compression ratio of 17:1, 18:1 and 19:1 and blending ratios B20, B40, B60 and B80.The fuel properties were strictly measured as per ASTM testing methods and these observed properties are verified to be well within the limits of ASTM D 6751 biodiesel standards. The combustion characteristics of heat release rate and combustion pressure of WCRBME & WCCSME were found closer to diesel.