Carbon nanotubes are one of the major research areas in the field of nanotechnology, due to its mechanical and electro-conductive properties in the field of engineering and medical sciences. This paper focuses on preparation of multi-walled carbon nanotubes (MWCNTs) for the mass production using thermal catalytic chemical vapour deposition method. The synthesis of MWCNTs was made by breakdown of acetylene (C₂H₂) gas and Fe/MgO acting as catalyst. The surface morphology and structure of MWCNTs were characterised by scanning electron microscopy (SEM). Also phase identification and crystalline size of the nanopowder were determined by XRD. The particle size of MWCNTs was verified by SEM analysis and it was in the range of 20–30 nm and elemental analysis was carried out through energy dispersive analysis X-ray. Furthermore, thermal decomposition of the material property was studied by thermogravimetric analysis.

Reducing wastewater contaminants is an emerging area of particular concern for many industrialized and developing countries in improving the ecological quality of their water sources.

This work is a performance study that investigated the nanorefrigerant CuO/AL₂O₃-R22 used in a refrigerator without any remodelling of the system. The refrigerator performance was then investigated using energy consumption test and enhancing heat transfer rate. The heat transfer enhancement was investigated on the surface of a refrigerator by using the nanorefrigerant Al₂O₃/CuO. The results indicate that CuO-R22 works normally and safely in a refrigerator and has better power consumption and heat transfer rate. Thus, using CuO-R22 as nanorefrigerant in domestic refrigerators is feasible for better heat transfer rate.

Conventional fluids such as water, ethylene glycol and mineral oils are normally used as heat transfer fluids. Various techniques are applied to enhance the heat transfer. Heat exchange of the coolant moving through the vehicle radiators is of incredible significance for the advancement of fuel utilisation. In this experiment, the heat transfer performance of the automobile radiator is evaluated experimentally. For this we have taken two different combinations of nanoparticles. Aluminium oxide (Al₂O₃) and magnesium oxide (MgO) nanoparticles are added to the base fluid (80% water + 20% ethylene glycol) at two concentrations 0.12% and 0.4% volume concentration considering the best pH for longer stability. Similarly, another combination with aluminium oxide (Al₂O₃) and titanium oxide (TiO₂) at the same volume concentrations of 0.12% and 0.4% in the base fluid is also prepared. Furthermore, this increases nanoparticle concentration, air velocity and nanofluid velocity and enhances the overall heat transfer coefficient.