Faculty Publications
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Item Controlled growth of 1D-ZnO nanotubes using one-step hot plate technique for CZTS heterojunction solar cells(Elsevier Ltd, 2020) Varadharajaperumal, S.; Alagarasan, D.; Ganesan, R.; Satyanarayan, M.N.; Hegde, G.Present work reports a simple, rapid, one-step hot plate technique for systematic growth transformation of highly oriented ZnO nanorods (ZNRs) into ZnO nanotubes (ZNTs). The controlled growth of ZnO nanostructures (nanorods and nanotubes) was achieved at low temperature (90 °C) in a short time (1hr) in a sealed weighing bottle (100 ml). It is observed that as the Zinc precursor concentration increases, a vertically grown ZnR morphology evolves into ZNT. The crystal structure of as-grown ZnO nanostructures, surface morphology, phase, and optical energy gap were respectively characterized by XRD, FESEM, Raman, XPS, CL and UV–Vis spectroscopy. Grown nanostructures are further explored for their application in CZTS based heterojunction photovoltaics. © 2019Item High power density and improved H2 evolution reaction on MoO3/Activated carbon composite(Elsevier Ltd, 2020) Sangeetha, D.N.; Holla, R.S.; Badekai Ramachandra, B.; Muthu, M.The formation of hexagonal MoO3 (h- MoO3) microrods was favoured at lower pH in the hydrothermal synthesis method. Symmetric and Hybrid supercapacitors were fabricated using h-MoO3/plastic bottle derived activated carbon (PAC) composite in 1 M Na2SO4 aqueous electrolyte. The operating voltage for the aqueous electrolyte was maximized to 1.6 V with this combination. The wide operating voltage led to a maximum specific capacitance of 211 Fg-1, power density of 287 W kg?1 and 79% efficiency even at 5000 charge-discharge cycles for the hybrid supercapacitor combination. The combined effect of PAC micropores along with the 1-D rod-shaped h-MoO3, helped in faster charge-transfer, hence increasing the efficiency of supercapacitors. Further, the composites of defective PAC (PDAC) together with the h-MoO3 when tested for hydrogen evolution reactions (HER), provided lesser onset potential and Tafel slope values of ?0.23 mV and ?93 mVdec?1. There was a change in the structural environment of carbon due to the heteroatom doping and dedoping producing defects in PAC, termed as PDAC. These defects together with the hexagonal microrods of MoO3 provided fast electron transfer towards hydrogen adsorption/desorption hence effectively producing H2. © 2019 Hydrogen Energy Publications LLCItem L, r-Stitch Unit: Encoder-Decoder-CNN Based Image-Mosaicing Mechanism for Stitching Non-Homogeneous Image Sequences(Institute of Electrical and Electronics Engineers Inc., 2021) Chilukuri, P.K.; Padala, P.; Padala, P.; Desanamukula, V.S.; Pvgd, P.R.Image-stitching (or) mosaicing is considered an active research-topic with numerous use-cases in computer-vision, AR/VR, computer-graphics domains, but maintaining homogeneity among the input image sequences during the stitching/mosaicing process is considered as a primary-limitation major-disadvantage. To tackle these limitations, this article has introduced a robust and reliable image stitching methodology (l,r-Stitch Unit), which considers multiple non-homogeneous image sequences as input to generate a reliable panoramically stitched wide view as the final output. The l,r-Stitch Unit further consists of a pre-processing, post-processing sub-modules a l,r-PanoED-network, where each sub-module is a robust ensemble of several deep-learning, computer-vision image-handling techniques. This article has also introduced a novel convolutional-encoder-decoder deep-neural-network (l,r-PanoED-network) with a unique split-encoding-network methodology, to stitch non-coherent input left, right stereo image pairs. The encoder-network of the proposed l,r-PanoED extracts semantically rich deep-feature-maps from the input to stitch/map them into a wide-panoramic domain, the feature-extraction feature-mapping operations are performed simultaneously in the l,r-PanoED's encoder-network based on the split-encoding-network methodology. The decoder-network of l,r-PanoED adaptively reconstructs the output panoramic-view from the encoder networks' bottle-neck feature-maps. The proposed l,r-Stitch Unit has been rigorously benchmarked with alternative image-stitching methodologies on our custom-built traffic dataset and several other public-datasets. Multiple evaluation metrics (SSIM, PSNR, MSE, L_{\alpha,\beta,\gamma } , FM-rate, Average-latency-time) wild-Conditions (rotational/color/intensity variances, noise, etc) were considered during the benchmarking analysis, and based on the results, our proposed method has outperformed among other image-stitching methodologies and has proved to be effective even in wild non-homogeneous inputs. © 2013 IEEE.Item Bioleaching of zinc from e-waste by A. aquatilis in fluidised bed bioreactor(Taylor and Francis Ltd., 2023) Minimol, M.; Shetty K, V.; Saidutta, M.B.Technological advancements with the use of new-generation electronic devices and accumulated electronic wastes (e-wastes) raise environmental concerns. E-waste, especially mobile phone Printed Circuit Boards (PCBs) is a rich source of metals. Bioleaching, a microbe-mediated metal dissolution process is employed for the recovery of metals. The operational parameters like particle size, inoculum percentage (v/v) and e-waste load (w/v) were optimised for Zn bioleaching by Alcaligenes aquatilis in shake flasks and fluidised bed bioreactor (FBR). The e-waste feed particle size of 0.175 mm and 5% inoculum was found to be the optimum for Zn bioleaching in both the shake flask and FBR. The optimum e-waste load was 5% in the shake flask and 2% in FBR. The maximum recovery of Zn was 0.6 mg/g (13.73%) in the shake flask and 0.57 mg/g (13%) in FBR, implying that FBR exhibits similar efficiency of Zn bioleaching as in the shake flask. Further three sequential batch runs increased the recovery to a maximum of 1.66 mg/g from 4.37 mg/g Zn present in the PCBs ie., 38% Zn recovery. This shows that efficient bioleaching of Zn on a larger scale can be achieved with sequential batches and applied for the simultaneous recovery of metals from PCBs. © 2023 Indian Institute of Chemical Engineers.Item Combustion modelling of sequential combustion in steam-methane reformation (SMR) furnace using adiabatic flamelet generated manifold(Elsevier Ltd, 2023) Joe, E.S.; Arumuga Perumal, D.A.Hydrogen as an energy vector of the future is being explored by many. Steam-methane reformation proves itself as a major source of hydrogen that is to play a major role in the electrification of the energy sector and decarbonization efforts. Detailed design and design optimization of SMR furnaces are required to maximize the production within a plant. Unit-operation level process of a cogeneration plant, producing both energy and hydrogen, have been studied by other researchers. Sequential combustion of natural gas/methane within the furnace of an SMR unit placed downstream of a power generating gas turbine is analysed within the present work using computational fluid dynamics. Flamelet generated manifolds as a means of combustion modelling for a large-eddy simulation is used to analyse the flow features, flame structure and the vortex-flame interaction. The fuel rich case features a stable flame although with a lower temperature, and the fuel lean case features an unstable flame. The outcomes of this study may be utilized by designers to study factors that bottle-neck production in the furnace. © 2023 Elsevier LtdItem Performance of Fluidized-Bed Bioreactor in Copper Bioleaching from Printed Circuit Boards using Alcaligenes aquatilis(Springer Science and Business Media B.V., 2024) Madhavan, M.; Shetty K, V.; Saidutta, M.B.Technological advancements have led to a demand for modern electronic gadgets and outdated ones discarded as electronic waste (e-waste). The printed circuit boards (PCBs) constitute a significant portion of these wastes that contain hazardous substances that mandate e-waste management. The rich source of precious and base metals makes it a resource for urban mining. Bioleaching, a process of biohydrometallurgy, an alternative to conventional heat and chemical-based metal recovery processes, can be efficiently applied for metal recovery from these wastes in an environmentally safe manner. The process parameters like particle size, inoculum size (v/v), and e-waste load (w/v) for bioleaching of Cu from PCBs in a Fluidized-Bed bioreactor (FBR) and shake flask using Alcaligenes aquatilis as bioleaching agent were optimized. The bioleaching of 47.99% and 37.54% of Cu from PCBs were achieved in shake flask and FBR, respectively. The optimal conditions of Cu bioleaching were 0.175 mm particle size, 5% (v/v) inoculum, and 2% (w/v) e-waste load with 169.45 mg/g and 132.55 mg/g of Cu recovery in shake flask and FBR at 84 and 96 h, respectively. Further, the Cu bioleaching was carried out in sequential batches to improve the recovery with the optimized conditions. There was a prominent increase in the cumulative %Cu bioleaching of about 80.02% after three sequential batch experiments from PCBs with an initial Cu concentration of 353.09 mg/g. The present study proves that sustainable heterotrophic bioleaching of Cu can be efficiently achieved in a Fluidized-bed bioreactor operated in sequential batch mode by Alcaligenes aquatilis. Graphical Abstract: (Figure presented.) © The Author(s), under exclusive licence to Springer Nature B.V. 2023. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.