Faculty Publications
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Publications by NITK Faculty
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Item The effect of the addition of strontium and cerium modifiers on microstructure and mechanical properties of hypereutectic Al-Si (LM30) alloy(ASTM International, 2013) Vijayan, V.; Ravi, M.; Prabhu, K.The present work deals with the melt treatment of LM30 hypereutectic Al-Si alloy using cerium and strontium and the assessment of its effect on microstructure and properties of the alloy. The addition of cerium simultaneously modified both primary and eutectic silicon, leading to an increase in ultimate tensile strength, as well as the wear resistance of the alloy. It was found that the coefficient of thermal expansion of the alloy decreased on modification of the microstructure. © 2013 by ASTM International.Item Green Synthesis of Silver and Gold Nanoparticles Using Root Bark Extract of Mammea suriga: Characterization, Process Optimization, and Their Antibacterial Activity(Springer New York LLC barbara.b.bertram@gsk.com, 2016) Poojary, M.M.; Passamonti, P.; Vasudeva Adhikari, A.V.The present study reports the green synthesis of silver and gold nanoparticles (NPs) from their respective precursors AgNO3 and HAuCl4, using root bark extract of Mammea suriga. Further, it describes the influence of various reaction parameters, such as pH, temperature, precursor concentration, and volume of the extract, on the morphology and size of the newly synthesized NPs. The biosynthesized NPs were characterized using UV–Vis spectroscopy, SEM, EDX, XRD, and FTIR. The formation of Ag and Au NPs was confirmed by their UV–Vis spectra. Ag NPs were efficiently synthesized at pH 10, with precursor concentration of 1 mM of AgNO3 and a reaction temperature of 80 °C, while Au NPs were successfully obtained at pH 8, with precursor concentration of either 1 or 3 mM HAuCl4, and the reaction was maintained at room temperature. The SEM study revealed that the particle size decreases with an increase in the extract volume used in the reaction. The XRD analysis confirmed the formation of metallic Ag and Au NPs having an average size of 50 and 22 nm, respectively. Further, the FTIR spectral data established the role of various functional groups of biomolecules involved in bioreduction as well as capping of NPs. The in vitro antibacterial screening results indicated that the NPs are potential antibacterial agents. Conclusively, the overall study showed that the root bark extract of M. suriga is an excellent eco-friendly and non-toxic source for the synthesis of biologically active Ag and Au NPs at optimal conditions. © 2016, Springer Science+Business Media New York.Item A comparative study on the effectiveness of system parameters in monitoring pre-load loss in bolted joints(Springer Verlag service@springer.de, 2018) Anginthaya, K.; Kuchibhatla, S.A.R.; Gangadharan, K.V.; Kishan, A.This article presents the monitoring of bolt loosening in a single bolted lap joint between two steel beams. The bolt loosening is initially studied using system modal parameters for various boundary conditions. Natural frequency and modal damping ratio in lower modes were not found to be reliable. Transmissibility function was seen to have a more reliable trend to identify the state of the joint. An in-house setup was developed to produce loosening in the bolted joint. Testing configuration was optimized by structural analysis. Strain measurements were carried out using Fiber Bragg-grating sensors while sinusoidal load was applied on the test structure. The results have been used to discuss a viable approach to identify the health of, or recognize a loosening trend, in a bolted joint. © 2018, The Brazilian Society of Mechanical Sciences and Engineering.Item Analysis and optimization of uniform FBG structure for sensing and communication applications(Springer, 2020) Divya Shree, M.; Sangeetha, A.; Krishnan, P.A uniform fiber Bragg grating sensor is sketched and inspected by the finite-difference time-domain method in furtherance of obtaining ultimate transmission and reflection spectra by optimizing the FBG parameters like refractive index, grating height, grating width, wafer width, wafer length. The maximum transmission power spectrum is achieved as ? 7 dB for the refractive index of 3.005, and the maximum reflection spectra are obtained as 6 dB for the grating height of 1 ?m which is enhanced nine times than the precedent work. The proposed FBG is a simple, light-weight, low-cost uniform structure, and it offers high reflectivity and ease of handling. Therefore, it is highly useful in sensing and communication applications. © 2020, Springer Science+Business Media, LLC, part of Springer Nature.Item High-Resolution Fiber Optic Sensor based on Coated Linearly Chirped Bragg Grating(Elsevier GmbH, 2020) Singh, M.; Raghuwanshi, S.K.; Prakash, O.; Kumar, P.K.a fiber optic strain sensor is proposed and experimentally demonstrated using fiber Bragg grating (FBG) based interrogation scheme. Due to fast response time and better sensitivity of graphene oxide (GO) material, coated linearly chirped fiber Bragg grating (LCFBG) is used in this work. Interrogation scheme is used for the efficient strain sensing by placing LCFBG within the Sagnac loop (wavelength dependent receiver). The GO deposition is confirmed by ultraviolet–visible spectroscopy, atomic force microscopy (AFM), and field emission scanning electron micrograph (FESEM). Our proposed fiber optic strain sensor possesses better resolution, stable operation in the infra-red region. In addition, sensor demonstrates 5.25 ?? static strain and 0.645 ??/?Hz dynamic strain resolutions, respectively. © 2020 Elsevier GmbHItem Real-time interrogation of fiber optic biosensor using TiO2coated etched long-period grating(American Institute of Physics Inc., 2020) Singh, M.; Raghuwanshi, S.K.In this work, a TiO2 coated etched long-period grating (e-LPG) fiber optic biosensor is developed for the detection of Escherichia coli (E. coli) bacteria in food items. Label-free Escherichia coli bacteria monitoring is done over the detection range of 0 cfu/ml-50 cfu/ml using an advanced spectral interrogation mechanism. The thin film deposition of 40 nm TiO2 over the e-LPG is confirmed by the microscopy method, such as scanning electron microscopy. In our proposed biosensor design, T4-bacteriophage is covalently immobilized over the TiO2 coated fiber surface. This biosensor system has reached sensitivity at 2.55 nm/RIU. Our experiments confirm the resolution and the limit of detection (3?/S) of 0.0039 RIU and 10.05 ppm, respectively. The proposed biosensor with enhanced sensitivity is suitable for monitoring harmful pathogens/infectious agents in various food products. © 2020 Author(s).Item Plasmonic Elliptical Nanohole Array for On-Chip Human Blood Group Detection(Institute of Electrical and Electronics Engineers Inc., 2023) Sahu, S.K.; Singh, M.A novel refractive index (RI) plasmonic biosensor with high sensitivity for human blood group detection is proposed and numerically investigated in the visible and near-infrared (NIR) regime. The proposed structure is based on a metal-insulator-metal (MIM) waveguide with an array of elliptical nanoholes. These nanoholes are used as the sensing surface and support important optical properties, such as extraordinary optical transmission (EOT) and nanoscale confinement of light. We have simulated and optimized the biosensor using RF module of COMSOL Multiphysics software, predicting the sensitivity values of three blood groups (A, O, and B) as 64.26, 101.16, and 82.1 nm/RIU, respectively. High sensitivity, precision, and portability make the reported sensor highly valuable for point-of-care applications, emergency situations, and resource-limited settings. By reducing the time for blood typing procedures and small sample volume requirements, MIM biosensor has the potential to enhance patient care and streamline medical processes. © 2023 IEEE.