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Degradation of surfaces of hydroturbine components caused by impact of abrasive particles carried by flowing water is a serious issue. To counteract the same, surface modification of turbine materials by the application of protective coatings is gaining popularity these days. In this work, Cr3C2–NiCr coating was deposited on CA6NM turbine steel by the HVOF spray process and studied with regard to its performance under different slurry erosion conditions. The effect of three parameters, namely average particle size of slurry particles, speed (rpm), and slurry concentration on slurry erosion of this coating material, was studied by using a high speed erosion test rig. The analysis of the surfaces of the samples before and after slurry erosion tests was done by using SEM. The HVOF sprayed Cr3C2–NiCr coating showed very good performance under slurry erosion in comparison with uncoated CA6NM steel.

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In this paper comparative analysis of R152a, R600, R600a, R410a, R290, R1234yf, R404a and R134a as refrigerants in two stage vapour compression refrigeration system has been done on the basis of energetic and exergetic performance. Performance parameters such as entropy generations, COP, exergetic efficiency, sustainability index were investigated at different ambient condition. It was found that both energy and exergy efficiencies of R134a is 8.97% and 5.38% lower than R152a and R600 respectively at -50 o C evaporating and 45 o C condensing temperatures. It was also observed that Irreversibility was minimal at higher evaporating temperatures and condenser was responsible for highest irreversibility or losses in two stage vapour compression refrigeration system. Sustainability index for R152a (1.96) was highest compared to other refrigerants.

Investigates the chemical resistance properties of lead silicate glasses suitable for compression‐type glass‐to‐metal (GM) seals, to aggressive solvents, containing different amounts of Na, K, and Ba as modifier ions, in acidic and alkaline media. In general attack rate was observed to be higher in alkaline medium, with maximum dissolution of 53.35 mg/cm2 compared to the maximum of 10.6mg/cm2 in acidic medium after 50 hour exposure. An increase in the concentration of BaO was found to decrease the degradation rate, while samples with higher molar amounts of either Na2O or K2O showed more though similar damage rates. The degradation rate was observed to be linear for higher BaO concentration in alkali solution, whereas in other cases accelerated rates were observed with longer exposure time. GM seals prepared with glass, having higher BaO content, were less susceptible to damage and had higher insulation resistances.