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Eco-friendly machining processes are gaining importance to avoid environmental pollution. Even though cutting fluids have a reasonably low cost, their handling and carrying costs are very high and also, owing to their toxic nature, dumping of used fluids is a big problem because it can be hazardous to workers and also to the environment. To avoid these problems, a minimal-cutting-fluid technique called minimum quantity lubrication (MQL) was used in machining. Owing to the development of nanomaterials by nanotechnology techniques, the effectiveness of the cutting fluids can be increased by dispersing them. In the present work a vegetable-oil-based MQL with different volume fraction of Al 2 O 3 (aluminium oxide) nanoparticles is used as the cutting fluid for machining Inconel 600 alloy. Experimental results for three different conditions -dry, MQL, MQL + Al 2 O 3 nanoparticlesare plotted. It is observed that surface finish and temperature dissipation of the workpiece increase with different volume fractions of Al 2 O 3 nanoparticle addition. It is also possible to observe a decrease in cutting forces and tool wear rate, and a reduction in the negative environmental effects, owing to Al 2 O 3 nanoparticle addition to MQL in machining Inconel 600 alloy.

Nanofluids exhibits larger thermal conductivity due to the presence of suspended nanosized solid particles in them such as Al2O3, Cu, CuO,TiO2, etc. Varieties of models have been proposed by several authors to explain the heat transfer enhancement of fluids such as water, ethylene glycol, engine oil containing these particles. This paper presents a systematic literature survey to exploit the thermophysical characteristics of nanofluids. Based on the experimental data available in the literature empirical correlation to predict the thermal conductivity of Al2O3, Cu, CuO, and TiO2 nanoparticles with water and ethylene glycol as base fluid is developed and presented. Similarly the correlations to predict the Nusselt number under laminar and turbulent flow conditions is also developed and presented. These correlations are useful to predict the heat transfer ability of nanofluids and takes care of variations in volume fraction, nanoparticle size and fluid temperature. The improved thermophysical characteristics of a nanofluid make it excellently suitable for future heat exchange applications. .

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Grinding requires high specific energy which develops high temperatures at wheel work piece interface. High temperatures impair work piece quality by inducing tensile residual stress, burn, and micro cracks. Control of grinding temperature is achieved by providing effective cooling and lubrication. Conventional flood cooling is often ineffective due to enormous heat generation and improper heat dissipation. This paper deals with an investigation on using TRIM E709 emulsifier with Al2O3 nanoparticles to reduce the heat generated at grinding zone. An experimental setup has been developed for this and detailed comparison has been done with dry, TRIM E709 emulsifier and TRIM E709 emulsifier with Al2O3 nanoparticles in grinding EN-31 steel in terms of temperature distribution and surface finish. Results shows that surface roughness and heat penetration were decreased with addition of Al2O3 nanoparticles.

Tin dioxide (SnO 2 ) is one of the transparent conductive oxides that has aroused the interest of researchers due to its wide range of applications. SnO 2 exists in a variety of polymorphs with different atomic structures and Sn–O connectivity. However, there are no comprehensive studies on the physical and chemical properties of SnO 2 polymorphs. For the first time, we investigated the structural stability and ground-state properties of 20 polymorphs in the sequence of experimental structures determined by density functional theory. We used a systematic analytical method to determine the viability of polymorphs for practical applications. Among the structurally stable polymorphs, Fm 3̅ m , I 4 1 / amd , and Pnma-II are dynamically unstable. As far as we know, no previous research has investigated the electronic properties of SnO 2 polymorphs from the hybrid functional of Heyd, Scuseria, and Erhzerhof (HSE06) except P 4 2 / mnm , with calculated band gap values ranging from 2.15 to 3.35 eV. The dielectric properties of the polymorphs have been reported, suggesting that SnO 2 polymorphs are also suitable for energy storage applications. The bonding nature of the global minimum rutile structure is analyzed from charge density, charge transfer, and electron localization function. The Imma -SnO 2 polymorph is mechanically unstable, while the remaining polymorphs met all stability criteria. Further, we calculated Raman and IR spectra, elastic moduli, anisotropic factors, and the direction-dependent elastic moduli of stable polymorphs. Although there are many polymorphic forms of SnO 2 , rutile is a promising candidate for many applications; however, we investigated the feasibility of the remaining polymorphs for practical applications.

Composite material consisting of single walled carbon nanotubes (SWCNTs) and metal oxide nanoparticles has been prepared and their hydrogen storage performance is evaluated. Metal oxides such as tin oxide (SnO2), tungsten trioxide (WO3), and titanium dioxide (TiO2) are chosen as the composite constituents. The composites have been prepared by means of ultrasonication. Then, the composite samples are deposited on alumina substrates and at 100 °C in a Sieverts-like hydrogenation setup. Characterization techniques such as transmission electron microscopy (TEM), Raman spectroscopy, scanning electron microscopy (SEM), powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, energy dispersive spectroscopy (EDS), CHN elemental analysis, and thermogravimetric (TG) measurements are used to analyze the samples at various stages of experiments. Hydrogen storage capacity of the composites namely, SWCNT-SnO2, SWCNT-WO3, and SWCNT-TiO2 are found to be 1.1, 0.9, and 1.3 wt %, respectively. Hydrogenated composite samples are stable at room temperature and desorption of hydrogen is found to be 100% reversible. Desorption temperature ranges and binding energy ranges of hydrogen have been measured from the desorption studies. The hydrogenation, dehydrogenation temperature, and binding energy of hydrogen fall in the recommended range of a suitable hydrogen storage medium applicable for fuel cell applications. Reproducibility and deterioration level of the composite samples have also been examined.

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