Amit Kumar

This study investigates the tool wear for turning Inconel-718 using the titanium nitride carbide tool inserts. This research work aims to compare the performance of processed images and acoustic waves used as an indirect technique for evaluating tool wear. The work targets to capture the tool wear and tool image after turning and acoustic wave during turning for each experimental run. The pixel area of the processed picture, the root-mean-square (RMS) of the acoustic wave, and the microscope tool wear of the tool maker were taken into consideration as output parameters for the change of operational parameters including feed, speed, and depth of cut. The performance of wear, pixel area, and RMS was compared using the Box Behnken method. Further, the correlation between the performance of tool wear, image processed pixel area, and RMS for the variation in input variable was obtained from interaction and main effects plots. The results demonstrated that at lower speeds (280[ ]rpm), lower feed rates (0.04[ ]mm/rev), and medium depth of cut (0.2[ ]mm), there was less wear, pixel area, and RMS. Wear, pixel area, and RMS have all decreased as a result of the tool and workpiece having less surface friction due to the reduced speed, feed, and medium depth of cut. From the analysis, it was also clear that the indirect evaluation of the wear can be successfully carried out using digital image pixel area and acoustic wave RMS for turning Inconel-718 using a titanium nitride-coated carbide tool.

This investigation delves into the behavior of copper oxide (CuO) as a solid lubricant inside zirconia toughened alumina (ZTA) ceramic composites. The investigation starts with the preparation of ZTA through co-precipitation followed by powder metallurgy to develop CuO (1.5 wt. %)/ZTA composites. In all cases, hot isotactic pressing is applied for densification. The fully densified samples are thoroughly mirror-polished to investigate the mechanical and tribological properties. A 1.8% reduction in micro-hardness and 6% improvement in fracture toughness are observed with incorporation of CuO into the ZTA matrices. The analysis reveals that the presence of ionic copper at the grain boundary leads to the formation of copper-rich phases, causing a decrease in hardness. However, the softer CuO particles contribute to crack bridging and crack deflection, enhancing fracture toughness. Subsequent investigation into the tribological properties highlights the positive influence of the softer CuO phases acting as a secondary component within the ZTA matrix. A significant enhancement of 39.34% in the Coefficient of Friction (COF) is achieved by incorporating CuO into the ZTA matrix. This improvement can be attributed to the formation of a patchy layer through smearing and squeezing actions on wear debris during sliding. The uniform patchy layer results in smoother and more polished surfaces, leading to an improvement in both the COF and specific wear rate. Further wear analysis reveals various phenomena contributing to surface wear, including pullout of grain particles, micro-fracture, high abrasions, and laminar removal of grains. Overall, the introduction of CuO proves to be beneficial, showcasing improved mechanical and tribological properties in the developed composites, with application in dies, inserts, sparkplugs, etc.

In a piping system, pipe bends are more flexible than straight pipes because of their curved geometry, supplemented by higher stress and strain concentration, leading to one of the crucial components in piping industries. Therefore, safe design of pipe bends is essential for smooth running of the piping system, and plastic collapse moment is one of its criteria. This paper utilizes three-dimensional finite element analyses to model empirical solutions for the plastic collapse moment for different angled pipe bends subjected to combined pressure and in-plane closing, in-plane opening, and out-of-plane bending moments. Plastic collapse moments for 30∘ to 180∘ pipe bends are determined for elastic perfectly plastic and strain hardening materials, employing large geometry change option and internal pressure effect. It is observed from results that pressure effect is more prominent in thinner pipe bends of larger bend angle under all bending cases. For in-plane opening and out-of-plane bending moments, collapse moment increases and then decreases with increase in pressure intensity for all sizes of pipe bend. However, for in-plane opening bending moment, collapse moments keep on decreasing for thicker ( r / t = 11.33) pipe bends. Finally, the study presents new improved plastic collapse moment solutions for different angled pipe bends under bending moment and internal pressure, derived from the finite element results of elastic perfectly plastic and strain hardening material models.

An overview of the significant innovations in photocatalysts for H2 development, photocatalyst selection criteria, and photocatalytic modifications to improve the photocatalytic activity was examined in this Review, as well as mechanisms and thermodynamics. A variety of semiconductors have been examined in a structured fashion, such as TiO2-, g-C3N4-, graphene-, sulfide-, oxide-, nitride-, oxysulfide-, oxynitrides, and cocatalyst-based photocatalysts. The techniques for enhancing the compatibility of metals and nonmetals is discussed in order to boost photoactivity within visible light irradiation. In particular, further deliberation has been carried out on the development of heterojunctions, such as type I, type II, and type III, along with Z-systems, and S-scheme systems. It is important to thoroughly investigate these issues in the sense of visible light irradiations to enhance the efficacy of photocatalytic action. In fact, another advancement in this area may include hiring mediators including grapheme oxide and metals to establish indirect Z-scheme montages with a correct band adjustment. The potential consideration of reaction chemology, mass transfer, kinetics of reactions, restriction of light diffusion, and the process and selection of suitable light and photoreactor also will optimize sustainable hydrogen output efficiency and selectivity.

The solar air heater’s thermal efficiency is relatively poor owing to the flat collector surface. This article’s primary objective is to increase the collectors’ thermal efficiency of rectangular ducts of solar air heater by adopting a novel V-shaped twisted rib element with staggering orientation. Experimentations are performed for various flow Reynolds numbers ranging from 3 k to 21 k, roughness pitch-to-rib height ratio ranging from 7 to 11, and staggering distance-to-rib height ratio between 2 and 6. Dispersion of Nusselt number over the collector surface is achieved through the liquid crystal thermography technique. Among the varied rib and flow constraints, it is observed that a maximum thermal performance enhancement index of 2.69 is observed, with the optimum value of the roughness parameter at a rib pitch-to-height ratio of 9 and a staggering distance-to-height ratio of 4. Mathematical correlation has also been developed using a regression model to estimate the Nusselt number in terms of non-dimensional roughness parameters. The percentage deviation between the Nusselt number attained from established relationships and the investigational results is found to be giving very satisfactory outcomes. The thermal efficiency of the smooth surface is recognized at 41.64% which increases for the roughened surface of twisted V-ribs to 73.63%. Hence employing twisted V-ribs as an artificial roughness element no doubt increases the Nusselt number, thermohydraulic performance enhancement index, and thermal efficiency, but it also exerts less frictional power of solar air heater.

The limitation of renewable energy is its fluctuation with time, season, and peak load demand. Hence, most of the research was carried using demand side management to reduce the actual consumption load to lower the peak load. This will also hamper the basic energy need of the facility. Therefore, the objective of the present study is to model a hybrid renewable energy system (HRES) to attain the specific consumption of a community health centre (CHC) in Yomcha, Arunachal Pradesh, with load shedding. The optimization of HRES is performed on HOMER® Pro software along with the demand side management algorithm and a maximum annual capacity shortage of 5%. Three different cases were compared based on feasibility, economics, and environmental basis to estimate the performance of the HRES. The results show that the proposed model is appropriate for the CHC over the previously proposed system. Moreover, HRES with (design-side management) DSM will reduce the overall cost and increase efficiency and reliability with an net present value of Rs. 3013482 and a cost of energy of Rs. 5.42/kW, renewable fraction 78%, internal rate of return 70%, return of investment 66%, and payback period of 1.4 years. Moreover, it reduces emissions, controls overloading during peak hours, and decreases load shifting. The study also supports the sustainable development goal (SDG)-7 set by the United Nation SDG Committee.