Faculty Publications
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Item Visible-light-driven photocatalytic degradation of organic dyes over cubic-phase and hexagonal-phase CdS: a comparative study(Springer, 2023) Mahendra, K.; Anupriya, J.; Gajendra, N.; Madhusudhan, C.K.; Nagaraja, B.S.; Pattar, J.; Udayashankar, N.K.Organic effluents—the gift of industrial development is a critical menace to environs as well as raising a question mark toward the sustainability of humans. In such a scenario, achieving consistent sunlight-driven photocatalytic degradation gains widespread attention due to its eco-friendly low-cost approach with high efficiency. Herein, the CdS-cubic nanoparticles have been synthesized using a simple chemical precipitation technique and structural transition to CdS hexagonal is obtained through annealing. Morphology study has validated the reduction in particle size of CdS cubic and corresponding enhancement in the surface are put forth by BET analysis. The better degradation capability of CdS cubic is demonstrated through the visible-light-driven photocatalysis of MB dye with a degradation rate constant of k = 0.02/min. Meanwhile, CdS hexagonal possesses a rate constant k = 0.005/min. The scavenger study reveals the vital role of conduction band electron and superoxide radical in decolorization. Moreover, lesser carrier recombination with more charge transfer is observed from PL and EIS, respectively, emphasizing the CdS-cubic nanoparticle's catalytic activity. © 2023, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.Item A comparative study of NOx mitigating techniques EGR and spark delay on combustion and NOx emission of ammonia/hydrogen and hydrogen fuelled SI engine(Elsevier Ltd, 2023) Pandey, J.K.; Dinesh, M.H.; Kumar, G.N.IC engines, the backbone of the transportation sector is facing energy insecurity and stringent environmental norms motivating researchers to look for alternate ways of revival. In pursuit hydrogen and its careers are seen as promising option. Aiming the same comparative-study is performed on NH3/H2 (7:3) and hydrogen under varying ignition (from −24°CA to −12°CA) and EGR rates (till 25%). Results indicate improved combustion for NH3/H2 for a small range of ignition than hydrogen, ∂P/∂θ and ∂Q/∂θ is improved before TDC and deteriorates after it. Cycle-by-cycle variations increase for a longer ignition range for NH3/H2, but NOx drops more rapidly. At −24°CA, NH3/H2 has observed a minimal gap in peak pressure, CoV and performance from hydrogen. Though a small EGR helps reduce NOx, cycle-by-cycle variations and CA90 reduce due to improved combustion for NH3/H2. ∂P/∂θ and ∂Q/∂θ improve for the same range too. However, hydrogen suffers adverse effects due to EGR that intensify with increasing EGR-rate. At higher EGR, unstable combustion and heterogeneity prevail, resulting in increased cycle-by-cycle variations and a rapid drop in peak pressure. The prolonged combustion witnesses a massive decline in NOx for both fuels; however, the gap between NH3/H2 and hydrogen entities reduces. NH3/H2 shows better efficiency than hydrogen for an efficient NOx control. However, higher fuel NOx maintains a significant difference for NH3/H2 than hydrogen. The study limits quantitative analysis of it and also NH3 emissions, which is another primary concern. © 2023 Elsevier LtdItem Comparative study on low velocity impact behavior of natural hybrid and non hybrid flexible thermoplastic based composites(SAGE Publications Ltd, 2023) Kumbhare, K.; Mahesh, V.; Joladarashi, S.; Kulkarni, S.M.The current study attempts to evaluate the low-velocity impact (LVI) behavior of jute and banana fiber-based hybrid and non hybrid green composites. The proposed composites are fabricated using compression moulding method with variety of positioning of layers namely jute-rubber-jute-rubber-jute (JRJRJ), banana-rubber-banana-rubber-banana (BRBRB), jute-rubber-banana-rubber-jute (JRBRJ) and banana-rubber-jute-rubber-banana (BRJRB). Thus developed composites are subjected to LVI testing using conical and hemispherical shaped impactor in drop weight impact testing machine and different impact velocities of 5 m/s, 10 m/s and 15 m/s. Based on the ability of the proposed composites to absorb energy, coefficient of restitution (CoR), energy loss percentage (ELP), and failure behaviour, the suggested flexible composites’ performances are assessed. The study reveals that JRJRJ composite exhibits better energy absorption capability and BRBRB exhibits least energy absorption capability compared to its counterparts. The damage study reveals that hemispherical impactor leads to more damage area due to its larger contact area whereas, conical impactor results in local penetration. Results reveals that inclusion of jute fiber as reinforcement results in better LVI properties compared to banana fiber. It is also clear that the presence of a compliant matrix improves energy absorption and damage resistance in flexible composites. © The Author(s) 2022.Item Comparative Study of Plasma Spray and Friction Stir Processing on Wear Properties of Mg-Zn-Dy Alloy(Springer, 2024) Rokkala, U.; Gudala, S.; Ramesh, M.R.Mg alloys are becoming increasingly popular as lightweight materials in recent years. Wear resistance, on the other hand, is a severe issue with Mg alloys. Plasma spray and friction stir processing (FSP) are being investigated in this context for developing composite surfaces with improved surface characteristics. Scanning electron microscopy (SEM), energy dispersive spectroscopy, and x-ray diffraction are used to examine the microstructural changes and phase changes of all materials. After FSP, SEM analysis indicated that the coated particles were equally dispersed throughout the Mg matrix. The composite samples had the lowest wear rate as compared to other samples, according to the wear tests. In comparison to AC, the F-1 sample surface has much higher wear resistance. As a consequence, the findings of this investigation for the F-1 sample appear encouraging for biological wear resistant applications. © ASM International 2023.Item A Comparative Study and Regression Analysis on Physico-Thermal Properties using Pongamia Pinnata - Waste Cooking Oil Methyl Ester Mixture(Taylor and Francis Ltd., 2025) Khale, B.R.; Kunar, B.M.; Murthy, C.S.Development of alternative fuels over the past three decades is trending research for the replacement or supplement of the mineral-based fuels. In the present study, a combined biodiesel mixture was prepared volumetrically from methyl esters of pongamia pinnata and waste cooking oil (50:50). Physico-thermal properties (Density, viscosity and calorific value) for blends varying from 5 to 30% were determined, for both combined biodiesel blends and their respective sources. Further, a comparative study on the physico-thermal properties of combined biodiesel blends with their respective sources was made. Similar trends were observed between the combined biodiesel blends and their respective sources. i.e., density and kinematic viscosity increased with increase in blend percentage. Alternatively, a decreasing trend was observed in the calorific value. Statistical analysis using Minitab was carried out. Backward elimination method was used to develop a regression model to determine the coefficient of determination between the properties and the volumetric contribution of blends. The models were significant at a confidence interval of 95%. The R-Square value for predicting density, kinematic viscosity and the calorific value was 99.37%, 99.05% and 99.84% respectively. © 2021 Taylor & Francis Group, LLC.Item Prediction of thermal conductivity of quartz chlorite schist rocks: a comparative study of MLR and ridge regression(Inderscience Publishers, 2025) Tripathi, A.K.; Pal, S.K.; Dileep, G.; Raj, A.Thermal conductivity is a key physical property with broad applications in engineering and geosciences, particularly in energy-efficient building design, geothermal energy systems, and subsurface geological studies. Accurate determination of thermal conductivity is essential for understanding heat transfer mechanisms in rock materials. However, direct in-situ measurement is often impractical due to technical and logistical constraints. As a result, indirect estimation methods, which establish empirical relationships between thermal conductivity and various physico-mechanical properties, have gained attention. This study investigates the thermal conductivity of quartz chlorite schist through laboratory experiments, alongside measuring key physico-mechanical properties, including P-wave velocity, porosity, density, and uniaxial compressive strength (UCS). The objective is to analyse the correlations between thermal conductivity and these properties to develop a reliable predictive model. Multiple regression and ridge regression analysis are employed to derive an empirical equation for estimating thermal conductivity based on the measured parameters. The findings of this study contribute to improving indirect assessment techniques, which are valuable for geotechnical and geological applications where direct measurements are challenging. © © 2025 Inderscience Enterprises Ltd.Item Comparative study of diode laser welding of solid-solution/precipitation-strengthened Fe-Ni-Cr-based superalloys(Taylor and Francis Ltd., 2025) Kumar, H.; Banerjee, K.; Aqeel, M.; Shariff, S.M.This study investigates autogenous diode laser welding of two differently strengthened Fe-Ni-Cr superalloys: solid-solution strengthened Incoloy 800 and precipitation-strengthened Incoloy A286. Effects of laser power, welding speed, and defocusing distance on weld bead geometry, microstructure, and mechanical properties were comprehensively analyzed. Butt weld joints produced with optimum and similar heat input conditions achieved joint efficiencies comparable to their base metals. Microstructural analysis of fusion zone revealed columnar dendrites of ?-(Ni,Fe) in both alloys, with A286 showing segregation of Ti, Cr, and Mo intermetallics at interdendritic regions, while Incoloy 800 exhibited refined columnar/equiaxed dendrites with chromium carbides and Fe-Ni-Ti intermetallics. Mechanical testing indicated enhanced yield strength but reduced impact toughness and marginal hardness gain in A286 welds, whereas Incoloy 800 welds maintained similar hardness to the base material. Overall, the study demonstrated utilization of fiber-coupled diode laser welding for producing butt-joints in both superalloys, supporting their potential adoption in high-temperature applications. © 2025 Taylor & Francis Group, LLC.