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This paper communicates the enhancement of heat transfer, friction characteristics and thermal performance of micro finned tube fitted with Left/Right and regular insert tape inserts using CNT and CNT/Al2O3 nanofluid. Two different concentrations of nanoparticles were used in the present investigation. In contrast, the CNT/Al2O3 nanoparticles are mixed in a weight ratio (50:50) and sonicated for about 2 hours using a bath type sonicator. The prepared nanofluids are stable for almost 48 hours without any sedimentation. Results show that the increase in nanoparticle concentration in the base fluid increases the performance index under turbulence flow regime while the Reynolds number in the range of 2000< Re<5500. Similarly, the Nusselt number and friction increase by 250% and 400%, respectively, with the maximum concentration of nanoparticle and minimum twist ratio. Results also reveal that the use of alternate arrangement increases the turbulence for maximum friction gain and improvement in the convective heat transfer coefficient. [ABSTRACT FROM AUTHOR]

Electro Chemical Machining (ECM) is a process that is used to machine extremely hard materials easily. It is a noncontact machining process. This ensures a higher tool life and no friction generated. The entire process is based on faradays laws of electrochemical process. With no heat affected zones (HAZ), this process holds a significant advantage over other high precision processes. This ensures that the material has neither thermal nor any other residual stresses. Nickel based alloys are known for their hardness and non-corrosive properties. This makes them unviable for machining using conventional methods as the overhead costs rise and makes them unproductive for use. ECM provides a better alternative comparatively. The alloy chosen for this analysis is Hastelloy C22. Its higher chromium content gives it better corrosion and pitting resistance. The objective of this analysis is to find the effects of various process parameters on MRR, surface finish, and dimensional deviation. The Taguchi technique has been used to investigate the effects of the ECMM process parameters and subsequently to predict sets of optimal parameters for maximum MRR and better surface finish. Grey analysis is done to find the optimal set of parameters for machining. [ABSTRACT FROM AUTHOR]

Internal combustion engines generate undesirable emissions during the combustion process. The NOX, HC, CO2 and CO emissions exhausted into the surroundings pollute the atmosphere that leads harming the human beings. The major causes of the emissions of pollutants are non-stoichiometric combustion, oxidation and reduction of nitrogen and impurities in the fuel and air. Thermal or catalytic converters and particulate traps are used for the post-treatment of exhaust gases [5]. In this investigation, an attempt has been made to control the engine exhaust emissions by using metal-oxide coated filters. The coating is performed by using vacuum coating unit over the surface of the mesh. The results obtained from the experiments using the filter coated with copper oxide, magnesium oxide, ferric oxide, cobalt oxide, copper oxide and their combinations were analyzed. The emission control achieved by adopting this technique was found to be effective. [ABSTRACT FROM AUTHOR]