Faculty Publications
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Item Electrochemical investigation on the corrosion of 18%Ni M250 grade maraging steel under welded condition in sulfuric acid medium(2013) Kumar, P.; Nityananda Shetty, A.N.The corrosion behavior of welded maraging steel in sulfuric acid solutions has been studied over a range of acid concentrations and solution temperatures by electrochemical techniques such as Tafel extrapolation and electrochemical impedance spectroscopy. The studies have revealed that the corrosion rate of welded maraging steel increases with the increase in temperature and increase in concentration of sulfuric acid in the medium. The thermodynamic parameters such as activation energy, enthalpy of activation and entropy of activation for the corrosion process are calculated. The results obtained through the two techniques are in good agreement. The surface morphology and surface composition of the corroded samples have been examined by scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analysis, respectively. © 2013 Allerton Press, Inc.Item Development of Multifunctional Thin Film Based X-Ray Intensity Filters for Space-Based Payloads(Springer New York LLC barbara.b.bertram@gsk.com, 2019) Prajwal, K.; Dey, A.; Sudhakar, M.; Nandi, A.; Esther, A.C.M.; Sridhara, N.; Yougandar, B.; Kumar, P.; Arya, S.; Rajendra, A.We report the development, thorough characterizations and space worthiness studies of multifunctional aluminized film as x-ray intensity filter for space-based payloads, suitably designed to place in Sun–Earth Lagrangian (L1) point. The L1 point is the ideal location for uninterrupted observation of Sun to study the solar flares in hard x-rays. For our specific purpose, we make use of two different types of x-ray detectors (e.g., CdTe and CZT) which are generally used for hard x-ray studies in the energy band of 5 to 200 keV. Further, these aforesaid two detectors require specified thermal control characteristic for optimal performance. Aluminization of Kapton films is proposed which would satisfy the thermo-optical and x-ray transmission requirements of the proposed payload. The developed aluminized films are thoroughly studied by field emission scanning electron microscopy and atomic force microscopy techniques for micro-structural characteristic, x-ray diffraction for phase purity, nanoindentation for mechanical integrity at micro-structural length scale and spectrophotometer for thermo-optical properties. X-ray transmission test is carried out with two radioactive sources, namely 55Fe and 241Am, with various aluminized Kapton layer combinations. Finally, space worthiness of the aluminized Kapton films is examined by accelerated environments, e.g. humidity, thermal cycling and thermo-vacuum tests. © 2019, ASM International.Item Synthesis of BNiO3 Nanocomposites for Photocatalytic Hydrogen Production Applications(Springer, 2024) Choudhary, R.K.; Kumaraswamy, G.N.; Baitha, R.; Kumar, M.; Shekokar, S.R.; Kumar, A.; Hussain, M.H.; Kumar, P.The pursuit of sustainable and clean energy sources has prompted significant research efforts toward developing efficient photocatalytic materials for hydrogen production. In this study, we present a comprehensive review of the synthesis of BNiO3 nanocomposites and their potential application as efficient photocatalysts for hydrogen production. The synthesis of BNiO3 nanocomposites involves the integration of bismuth oxide (Bi2O3) and nickel oxide nanoparticles with boron nitride nanosheets. Various synthesis techniques have been employed to fabricate these nanocomposites, including sol–gel, hydrothermal, and co-precipitation methods. The choice of synthesis method significantly influences the nanocomposites' structural, morphological, and optical properties, thereby affecting their photocatalytic performance. The morphological characterization techniques, such as scanning electron microscopy, transmission electron microscopy, and X-ray diffraction, have been utilized to investigate the structural and morphological properties of BNiO3 nanocomposites. The photocatalytic activity of BNiO3 nanocomposites for hydrogen production has been extensively studied. The mechanism of hydrogen production involves the absorption of solar energy by the BNiO3 nanocomposites, followed by the generation of electron–hole pairs. This report provides valuable insights into the synthesis techniques, characterization methods, and photocatalytic performance of BNiO3 nanocomposites. Further research is warranted to optimize the synthesis parameters and explore novel strategies for enhancing the efficiency and stability of these nanocomposites, ultimately contributing to the development of sustainable energy solutions. © The Institution of Engineers (India) 2024.Item Green synthesis of CuO/MgO/ZnO nanoparticles using Costus pictus leaf extract for effective antibacterial applications(Elsevier B.V., 2024) Kumar, P.; Ramesh, M.R.; Doddamani, M.; Suresh, J.; Lingaraj, R.In recent years, environmentally friendly methods have garnered significant attention in developing novel nanoparticles (NPs). This study focuses on the green synthesis and characterisation of CuO/MgO/ZnO NPs using Costus pictus D. Don Plant extract as a green reducing and capping agent. X-ray diffraction (XRD) analysis was employed to assess the purity of NPs, whereas Fourier-transform infrared (FTIR) and UV–Vis spectroscopy were employed to study the chemical composition and absorption peaks of the synthesised NPs. The Field-emission scanning electron microscopy (FE-SEM) images revealed a distinctive flower-like morphology of NPs, and their stability and dispersion were supported by a negative zeta potential of −14.8 mV. The significant surface area (87.742 m2/g) of CuO/MgO/ZnO NPs was obtained from Brunauer-Emmett-Teller (BET) analysis. Transmission electron microscopy (TEM) and selected area electron diffraction (SAED) analysis confirmed that the particle size of NPs is nearly 50 nm and is poly-crystalline. Finally, the synthesised NPs were tested against the bacteria using the agar-well diffusion method. Notably, CuO/MgO/ZnO NPs exhibited better antibacterial activity against Pseudomonas aeruginosa, yielding a substantial inhibition zone of 23.33 ± 2.08 mm. © 2024 Elsevier B.V.Item Fabrication and Characterization of Silicon Dioxide-Reinforced Polydimethylsiloxane Composite Coating for Corrosion Protection of Galvanized Iron(SAE International, 2024) Kumar, P.; Ramesh, M.R.; Doddamani, M.The present work highlights the significance of nanocomposite coatings for their ease of processing and applicability in combating corrosion. Ongoing research is dedicated to the development of an effective nanocomposite hydrophobic coating. A hydrophobic nanocomposite coating was deposited on galvanized iron (GI) using a sol-gel route with polymethylsiloxane (PDMS) reinforced with nano-SiO2. Surface morphology and chemical composition analysis, conducted with scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDAX) and Fourier transform infrared spectroscopy (FTIR), revealed the coating's structural and compositional attributes. The resulting hydrophobic coating exhibits a water contact angle (WCA) of 104.1°, indicating a 30.45% increase compared to bare GI. Subsequent to these characterizations, the adhesion of the coated GI, rated as 4B per ASTM D3359, is followed by commendable resistance to corrosion, as evidenced by electrochemical tests. The corrosion rate for the coated GI sheet is notably low, at 62.78 × 10-3 mpy, underscoring its anti-corrosive efficacy. © 2024 SAE International.Item Green synthesis of fe/ni/cr oxide nanoparticles using costus pictus plant extract: Microstructure and biological properties(World Scientific, 2024) Kumar, P.; Ramesh, M.R.; Doddamani, M.; Suresh, J.Superior qualities to bulk material and larger surface area to volume ratio are some of the primary reasons that account for the wide use of nanoparticles (NPs) in biological applications. Advancements in molecular-level engineering and environmental and health concerns are driving factors in the green synthesis of NPs. Plant-based NP synthesis provides a good alternative compared to hazardous physical and chemical techniques of synthesis of NPs. An experimental study is carried out on the green synthesis of Fe/Ni/Cr oxide NPs using Costus pictus extract. The study encompassed an array of characterization techniques, including UV-visible spectroscopy for absorption properties, X-ray diffraction (XRD) for crystallinity assessment, and Fourier-transform infrared (FTIR) spectroscopy to probe the presence of phenolic groups in flavonoids that influence NP formation. Surface morphology and composition were elucidated using scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS), while transmission electron microscopy (TEM) affirmed the NPs' size (approximately 20 nm). The surface area of the NPs, 96.806 m2/g, was determined through BET analysis. Furthermore, the antibacterial potential of the NPs against various bacterial strains, including S. mutans, E. coli, P. aeruginosa, and S. aureus, was investigated using the agar well diffusion method. The NPs showed good antibacterial potential against bacterial species E. coli and P. aeruginosa. © 2024 World Scientific Publishing Company.Item Optimization of Processing Parameters and Wear Performance of B4C Reinforced AA6061 Composites Through Taguchi Methodology(Springer, 2025) Manjunatha, C.; Varun, K.R.; Nagaraja, K.C.; Soni, P.K.; Kumar, R.S.; Prasad, C.; Kumar, P.; Nithesh, K.G.Two or more elements with different physical and chemical characteristics make up the composite material. The composite may be prepared using a variety of methods, but stir casting is a popular choice since it is easy to use and reasonably priced. In this investigation, stir casting was used to create AA6061-Boron Carbide (B4C) composites. Composites with 10% weight percentage of B4C were selected for wear analysis. The Taguchi technique was applied to the wear study in order to identify the ideal values. Utilizing a Pin-on-Disk testing device under dry sliding circumstances, anthropological investigations were carried out. With B4C content and wear depth as the system output, the three factors load (N), sliding distance (SD), and sliding velocity (SV) were evaluated using the L27 orthogonal array. To comprehend the impact of factors and how they contribute to wear loss, analysis of variance was used. Experimental tests were conducted to validate the analysis results using the optimal values. Scanning Electron Microscopic (SEM) analysis of the samples revealed both abrasive and adhesive wear on the contact surfaces of the specimens, aiding in understanding the wear mechanisms in the composites. © The Institution of Engineers (India) 2024.