Faculty Publications

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Publications by NITK Faculty

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    Comprehensive physical model study on wave transmission at plate structure
    (CAFET INNOVA Technical Society 1-2-18/103, Mohini Mansion, Gagan Mahal Road, Domalguda, Hyderabad 500029, 2011) Shirlal, K.G.; Rao, S.; Varghese, R.V.
    Investigators are increasingly concentrating their focus of research on coastal protection which is shifting from the hard measures to eco-friendly solutions with optimal usage of construction materials. A structure located near the water surface is known to be effective in bringing down the wave activity behind it, since; the energy of the waves is concentrated in the region close to the surface. This paper explains the comprehensive experimental study to evaluate the transmission coefficients (Kt) of various configurations of submerged plate structures. Kt for various plate configurations such as single plate, twin plate and combined plate are obtained. It is found that a single plate inclined at 60° to the horizontal is generally effective i. e. Kt ? 0.6 to a large extent. However, the twin and combined plate structures improved the performance. © 2011 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.
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    Eclipta prostrata leaf aqueous extract mediated synthesis of titanium dioxide nanoparticles
    (2012) Govindasamy, G.; Rahuman, A.A.; Priyamvada, B.; Khanna, V.G.; Devarepally, D.K.; Jose, P.J.
    Eco-friendly, nontoxic, inexpensive, abundantly available hitherto unreported Eclipta prostrata leaf extract is used for the biosynthesis of titanium dioxide nanoparticles (TiO 2 NPs). The TiO 2 NPs were characterized by FTIR, XRD, AFM and FESEM analysis. FTIR peak implicated the role of carboxyl group OH stretching amine NH stretch in the formation of TiO 2 NPs. XRD characterized in crystallographic plane of rutile phase. AFM showed uneven surface morphology which indicates the presence of both individual and agglomerated nanoparticles. FESEM analysis showed shape in spherical clusters, quite polydisperse and it ranges in size from 36 to 68 nm with calculated average size of 49.5 nm. In this paper, we have demonstrated a novel biological route for the synthesis of TiO 2 NPs. © 2011 Elsevier B.V. All rights reserved.
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    Durability studies on eco-friendly concrete mixes incorporating steel slag as coarse aggregates
    (Elsevier Ltd, 2016) Palankar, N.; Ravi Shankar, A.U.; Mithun, B.M.
    The present study discusses the durability performance of alkali activated concrete mixes containing steel slag as coarse aggregates. Steel slag aggregates, a waste product obtained from iron and steel industry are incorporated as coarse aggregates in alkali activated slag concrete (AASC) and alkali activated slag fly ash concrete (AASFC) by replacing traditional natural aggregates. The mix design for AASC and AASFC mixes are optimised to obtain sufficient strength for structural purposes and then steel slag coarse aggregates are incorporated at different replacement levels (0%, 50% and 100% by volume of total coarse aggregate content). Durability properties such as long term ageing performance, water absorption, volume of permeable voids, resistance to sulphuric acid attack and resistance to magnesium sulphate attack are studied in detail and compared with conventional Ordinary Portland Cement Concrete (OPCC). The ecological and economical analysis of concrete mixes is also carried out. It was found that the AASC and AASFC mixes displayed better durability performance as compared to OPCC. The inclusion of steel slag aggregates slightly reduced the durability performance of AASC and AASFC mixes. The AASC and AASFC with steel slag aggregates displayed lower energy requirement and lower production cost as compared to OPCC, thus proving it to be eco-friendly. © 2016 Elsevier Ltd. All rights reserved.
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    Eco-friendly benzimidazolium based ionic liquid as a corrosion inhibitor for aluminum alloy composite in acidic media
    (Elsevier B.V., 2017) Kshama, S.; Nityananda Shetty, A.N.
    A novel, relatively inexpensive ionic liquid, 1.3-bis[2-(4-methoxyphenyl)-2-oxoethyl]-1H–benzimidazol-3-ium bromide (MOBB), was synthesized and characterized using FTIR, NMR, LC-MS and single crystal XRD (SCXRD) techniques. MOBB was evaluated for its corrosion inhibition properties on 6061 Al-15 vol% SiC (P) composite in 0.1 M HCl and 0.1 M H2SO4 media at different temperatures (30–50 °C) by electrochemical impedance spectroscopy and potentiodynamic polarization methods. The adsorption of MOBB on the composite was predominantly through chemisorption, obeying Langmuir adsorption isotherm. Inhibition efficiencies of 98.7% in HCl and 98.8% in H2SO4 were obtained, MOBB acting as a mixed type of inhibitor with predominant cathodic control. © 2016
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    A study on the effect of rejuvenators in reclaimed asphalt pavement based stone mastic asphalt mixes
    (Springer, 2019) Durga Prashanth, L.; Palankar, N.; Ravi Shankar, A.U.
    The present paper focuses on the behavior of Stone Mastic Asphalt (SMA) mixes incorporating rejuvenated Reclaimed Asphalt Pavement (RAP) materials. The RAP materials were tested for its physical properties and later were rejuvenated using various rejuvenators such as waste cooking oil, waste engine oil and shredded plastics. The rejuvenated RAP materials were incorporated in the SMA mixes at various replacement levels i.e. 0%, 30%, 50% and 70% (by weight). Various binder properties such as viscosity, rheological properties and chemical composition were evaluated for the aged and rejuvenated material. The rejuvenators were incorporated at different dosage levels i.e. 2%, 4% and 6% (by weight of binder). The optimal rejuvenation dosage for each type of rejuvenator was identified and mix design for the SMA was optimized for evaluating its physical and mechanical properties. Based on the results, the optimum rejuvenator dosage was identified at 6% for waste cooking oil and waste engine oil, while 2% for shredded plastics. It was observed that the addition of rejuvenators improved the performance of RAP based SMA mixes. © 2019, Chinese Society of Pavement Engineering. Production and hosting by Springer Nature.
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    A Study on Elastic Deformation Behavior of Steel Fiber-Reinforced Concrete for Pavements
    (Springer, 2019) Chandrashekar, A.; Palankar, N.; Durga Prashanth, L.; Mithun, B.M.; Ravi Shankar, A.U.
    The present study discusses the experimental investigation of steel fiber-reinforced concrete slabs on ground under wheel load with the objective of understanding the stress behavior when subjected to central and edge wheel loading. The steel fiber-reinforced fly ash concrete slabs of 900 mm × 900 mm, 150 mm thickness were investigated in this study. Strain gauges and data acquisition system were used to measure the strains at the center and the edge of the slab under the action of the load. The load versus strain relationship under central and edge loading for reference concrete and steel fiber fly ash concrete showed a linear variation even up to the pressure of 2.5 MPa, which is much beyond the conventional tyre inflation pressure of 0.8 MPa. The load versus strain graphs clearly signify the higher modulus of elasticity of fly ash steel fiber-reinforced concrete. The stresses were calculated using IITRIGID software and ANSYS software and were found matching significantly. The value of modulus of elasticity of fly ash steel fiber-reinforced concrete (FS) using ANSYS model for experimental values of load and strains measured was approximated to 34,000 N/mm2 and was found to closely match with the experimentally obtained modulus of elasticity. No significant effect of Poisson’s ratio of concrete on load–strain characteristics was observed within the range 0.15–0.2 of concrete. © 2019, The Institution of Engineers (India).
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    Development of energy efficient organic bricks in construction using IOT and perlite
    (Taylor and Francis Ltd., 2021) Shubhananda Rao, P.; Ram Chandar, K.R.
    The study focuses on improvement of bricks in mechanical properties, reduction of energy consumption, making more economical and environmentally friendly by saving the depleting resources. The bricks were mixed in different proportions, by replacing sand with Iron Ore Tailings from 30 to 60 percent at 10 percent interval, cement from 10 to 20 percent at 5 percent interval and perlite at 2 and 5 percent to make bricks of 230 mm×112.5 mm×75 mm dimensions. The bricks were tested for compressive strength, water absorption and thermal conductivity. From these tests among different combinations, IOTs:Sand:Cement:Perlite 50:25:20:5 combinations have yielded better results by satisfying Indian Standard (IS) codes and this is taken as optimum dosage of raw materials. Model rooms are constructed using these bricks to access the effectiveness of thermal conductivity to compare with the ordinary conventional brick (fired brick) room, both rooms are of the same dimension and exposed to same environmental conditions. Thermal conductivity is assessed by measuring the temperature on walls of all sides of the room at different timings of the day. The results revealed that heat transferred from the outside to inside of the walls of the model room constructed with IOT-perlite bricks was at least 2°C less compared with that of ordinary bricks. Lower thermal conductivity leads to energy savings and results established 8 percent of energy savings with IOT-perlite bricks. The study proved the eco-friendly bricks by using the mine waste, lower thermal conductivity, good strength and light weight in structure. © 2020 Informa UK Limited, trading as Taylor & Francis Group.
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    Visible light mediated photocatalytic dye degradation using Ag2O/AgO-TiO2nanocomposite synthesized by extracellular bacterial mediated synthesis - An eco-friendly approach for pollution abatement
    (Elsevier Ltd, 2021) Kulal, D.; Shetty K, V.
    A large quantity of dyes released with textile industry effluents has raised a lot of concern due to their harmful and toxic effect on the ecosystem. The present study reports a novel method for the synthesis of visible light active photocatalyst by a bacterial based synthesis approach for the degradation of dyes. Ag2O/AgO-TiO2 nanocomposite particles with an average crystallite size of 38» nm, containing rutile TiO2 were synthesized using the cell free supernatant of the culture broth of Alcaligenes aquatilis. The particles were spherical, distinct with average particle size of 39.6» nm. The particles were found to be visible light active with the band gap energy value of 1.5» eV and photocatalytically active in the degradation of Reactive Blue 220 (RB 220). Around 96% of 100» ppm dye could be degraded in 90» min under visible light irradiation using the biosynthesized Ag2O/AgO-TiO2 nanocomposites. The biosynthesized nanocomposite exhibited good solar photocatalytic activity not only in the degradation of RB 220, but also in degrading the azo dyes, such as Acid Yellow 17 and Methyl Orange. The activity of biosynthesized nanocomposite was found to be better than that of Bio-TiO2. These results demonstrated an eco-friendly, potentially economical and greener method for the synthesis of Ag2O/AgO-TiO2 nanocomposites, with involvement of minimum technical challenges in terms of downstream processing and less energy consumption, with a broad scope of application in solar light mediated photocatalytic treatment of waste water. © 2021 Elsevier Ltd.
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    Hydraulic performance of perforated enlarged pile head breakwaters through laboratory investigation
    (Elsevier Ltd, 2021) Suvarna, P.S.; Hunasanahally Sathyanarayana, A.H.; Umesh, P.; Shirlal, K.G.
    An economical, ecofriendly and efficient breakwater system is vital for coastal protection and harbour tranquility. In this regard, various researchers are working to develop the appropriate solutions to encounter site-specific challenges. With this viewpoint, concept of enlarged pile head breakwater is developed. The study focuses on improving the hydraulic efficiency of pile breakwater by enlarging the structure near the free surface and providing it with perforations. Effect of percentage distribution of perforations, size of perforations and percentage of perforations on wave transmission, reflection and dissipation characteristics of the structure is investigated. The physical experiments are conducted in a two-dimensional wave flume under varying monochromatic wave climates. Results indicate that the pore size highly dominants the wave attenuation than considering the increasing percentage of perforations with the small size of the pore. Perforations effectively reduce the Kt of about 10%–18% to that of non-perforated pile head breakwater. Hydraulic efficiency of enlarged pile head breakwater is optimum when D/Hmax = 0.6, Y/Hmax = 1.0, b/D = 0.2, S = 0.25D, pa = 75% and P = 22.5 at 0.3 m water depth. A hybrid theoretical solution is developed based on the current set of experimental data for the quick estimate of hydraulic coefficients. The proposed hybrid equation for the perforated pile breakwater predicts more desirable values of Kt, Kr and Kd. The proposed concept of breakwater gives a reasonably enhanced hydraulic efficiency than the compared type of breakwaters. © 2021 Elsevier Ltd
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    A comprehensive review on performance and machinability of plant fiber polymer composites
    (John Wiley and Sons Inc, 2022) Hemath Kumar, H.; Rangappa, S.; Siengchin, S.; Gorbatyuk, S.; Manimaran, P.; Alka Kumari, C.; Khan, A.; Doddamani, M.
    In recent years, the revolutionary utilization of plant fibers in polymer laminates significantly influenced environmental effects. Presently, there is progression attention in advancing bio-based materials by acquiring plant fibers from lignocellulosic components for different applications like non-structural, structural laminates, automobile components, ballistics, flooring, household utensils, and aerospace parts. These bio-based, eco-friendly components have been recognized as next-generation contestants for higher-efficacy, sustainable, cheap, environmentally friendly, and lightweight composites. Different kinds of synthetic and natural biopolymers and bio-based nanoparticles have been applied to produce sustainable materials. Bio-based polymer composites manifest unique characteristics of both eco-reinforcement and sustainable resin. This review comprehensively communicates the general characteristics and principles of nanoparticles, polymers, and their respective composites. In addition to the machining characteristics, challenges and future perspectives of the polymer composites have also been reviewed. © 2021 Society of Plastics Engineers.