Faculty Publications
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Item Implication of concrete with chemical admixture cured in low temperature on strength, chloride permeability and microstructure(Springer, 2019) Ghosh, A.H.; Das, B.B.Concrete does not gain complete strength when cured in low temperature as the hydration of cement does not take place completely. The concrete cured in cold weather does not gain early strength and leads to improper setting and uneven strength gain due to the freezing of the water mixed with the cement. Hence, there are many strength-related problems faced at site due to cold weather particularly in parts of north India where the temperature reaches below freezing point of water during the winter season. The study focused on the effect of combination of accelerator, superplasticizer and air-entraining admixture on microstructure, compressive strength and chloride ion penetration of concrete cured at +5 °C and a comparative study with normal cured concrete with chemical admixture. Five different mixes were used containing varying amount of accelerators, superplasticizers and air-entraining admixture of a manufacturer which are available for use in India. The results for compression strength show that the concrete mix with higher dosage of accelerator had higher strength. The strength results were nearly the value of normal cured concrete with chemical admixture. Rapid chloride permeability test showed very low permeability for all of specimens of last mix, and results were nearly comparable to normal cured concrete. The microstructure study of concrete with admixture ensures a dense structure formation resulting in higher strength at low temperature. © Springer Nature Singapore Pte Ltd. 2019.Item Fast Setting Steel Fibre Geopolymer Mortar Cured Under Ambient Temperature(Springer, 2021) Prasanna, K.M.; Theodose, I.; Shivaprasad, K.N.; Das, B.B.Cement and cementitious materials are being used worldwide as the most popular multipurpose construction materials but the greenhouse gas such as carbon dioxide (CO2) produced during its manufacturing process creating a huge environmental hazard, thus efforts have been made for alternative binders. Geopolymer binder is new age binder alternative to ordinary Portland cement in infrastructure projects because it is produced from eco-friendly and industrial waste materials. This study was aimed to produce fast setting with ground-granulated blast-furnace slag (GGBS) in fly ash-based geopolymer mortar incorporated with steel fibres cured under ambient temperature. In this research, alkaline to binder ratio was varied from 0.5 to 0.8, crimped steel fibre are varied from 0.5 to 1.5% by total volume of binder and combination of fly ash (FA) and GGBS (100%:0%, 90%:10%, 80%:20%, 70%:30%, 60%:40% and 50%:50%) as binder were used for preparation of fibre geopolymer mortar. The tests conducted include stetting time and flowability of geopolymer mortar, compressive strength and microstructural characterisation of steel fibre geopolymer mortar. The tests for compressive strength were carried out on standard size of mortar samples at curing period of 3, 7 and 28 days. It is noted from the test results that increase in GGBS content setting times were decreased; however, the compressive strength of fly ash-based geopolymer mortar increased. The highest compressive strength at 28 days of curing period was found to be 69.5 MPa, which is obtained with content of 1% of steel fibres and alkaline to binder ratio of 0.6 with 50%:50% binder’s proportions. Further, it is observed that the incorporation of steel fibres in plain geopolymer mortar have enhanced the compressive strength and optimum dosage of fibres was found to be 1%. © 2021, Springer Nature Singapore Pte Ltd.Item Microstructural Aspects of Metal-Matrix Composites(Elsevier, 2021) Bhat Panemangalore, D.B.; Shabadi, R.Microstructures play a very important role in deciding the end properties of an alloy or a composite. Optimized microstructure could be obtained by a careful choice of processing technique and selection of materials. Metal-matrix composites (MMCs) that have been developed significantly over the last five decades possess valuable properties. MMCs can be tailored with myriad of variations to suit for a particular application and hence they belong to a unique class of materials. However, it is important to understand the microstructural aspects to understand the behavior of the component in different environmental and working conditions. This article presents an overview on different microstructural aspects of metal matrix composites. © 2021 Elsevier Ltd. All rights reserved.Item Factors Shaping Customer Perception in Online Food Delivery: A Smart PLS-Based Approach(Springer Science and Business Media Deutschland GmbH, 2025) Thonse Hawaldar, I.T.; Frederick, D.P.; Samartha, S.; Fernandes, A.S.This research investigates how different customer perceptions—assessed via “prior experience, perceived benefits, subjective norms, and system quality”—related to online food delivery services (OFDS) influence consumer perception. It examines the impact of these factors on customer attitudes and perceptions, proposing a solution in which the mediating variable (customer attitude) facilitates the connection between the independent variables and the dependent variable, namely consumer perception. Results reveal that consumer perceptions, including perceived advantages such as convenience, time-saving, food variety flexibility, and simplicity of use, greatly influence customer attitudes. The customer experience is significantly dependent on technology, mobile applications, and innovative delivery methods. Research indicates that understanding consumer requirements and using technology to improve quality is crucial. These results have significant implications for food delivery aggregators and restaurants regarding consumer perception. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2025.Item Mechanical and tribological behaviour of epoxy reinforced with nano-Al2O3 particles(Trans Tech Publications Ltd ttp@transtec.ch, 2014) Kurahatti, R.V.; Surendranathan, A.O.; Ramesh Kumar, A.V.; Auradi, V.; Wadageri, C.S.; Kori, S.A.In the present work systematic study has been conducted to investigate the matrix properties by introducing nanosize Al2O3 (particle size 100 nm, 0.5-10 wt %) fillers into an epoxy resin. High shear mixing process was employed to disperse the particles into the resin. The experimental results indicated that frictional coefficient and wear rate of epoxy can be reduced at rather low concentration of nano-Al2O3. The lowest specific wear rate 0.7 × 10-4 mm3/Nm is observed for the composites with 1 wt.% which is decreased by 65% as compared to unfilled epoxy. The reinforcement of Al2O3 particles leads to improved mechanical properties of the epoxy composites. The results have been supplemented with scanning electron micrographs to help understand the possible wear mechanisms. © (2014) Trans Tech Publications, Switzerland.Item Multilayer Zn-Ni-Al2O3 coatings for corrosion protection(Inderscience Publishers, 2014) Ullal, Y.; Hegde, A.C.The paper reports the development of composite coatings of Zn-Ni-Al2O3 by composition modulated multilayer (CMM) technique using m-aminophenol and gelatin as additives. The bath constituents and deposition parameters were optimised by conventional method. The role of gelatin and m-aminophenol in the bath was analysed by cyclic voltammetry (CV) study. Corrosion performance of the monolayer coatings was enhanced further by multilayer technique. The modulation in composition was effected by pulsing the DC in square-wave patterns. The coatings configurations were optimised for peak performance of the coatings against corrosion. It was found that corrosion resistance of CMM coatings increased with number of layers up to certain optimal numbers, and then decreased. Incorporation of Al2O3 particles into metal matrix was confirmed by EDAX. Formation of layered coating and their phase structures were analysed by scanning electron microscopy (SEM) and X-ray diffraction (XRD) study. Reasons responsible for better corrosion resistance of CMM composite coatings are analysed and results are discussed. Copyright © 2014 Inderscience Enterprises Ltd.Item Studies on corrosion of Mg-Al-Zn alloy in 30% aqueous ethylene glycol(Trans Tech Publications Ltd ttp@transtec.ch, 2015) Medhashree, H.; Nityananda Shetty, A.The Mg-Al-Zn alloy is used in the coolant systems of automobile engines. Corrosion of Mg-Al-Zn engine components by coolants, which consist of 30% aqueous ethylene glycol as a coolant composition, is an important issue in automobile industries. With this preview, in the present study it is intended to study the effect of environmental contaminant sulphate ions on the corrosion behavior of Mg-Al-Zn alloy in 30% (v/v) aqueous ethylene glycol solution. Electrochemical investigations were carried out by potentiodynamic polarization and electrochemical impedance spectroscopy techniques. Scanning electron microscopy (SEM) and energy dispersion X-ray analysis (EDX) were used to study the surface morphology and composition of the alloy. Activation parameters for the corrosion process were calculated by conducting the corrosion studies at different temperatures. It was observed that corrosion rate of the alloy in 30% (v/v) aqueous ethylene glycol increases with the increase in the concentration of sulphate ions and also with the increase in temperature. © (2015) Trans Tech Publications, Switzerland.Item Electrodeposited Ni-P alloy thin films for alkaline water splitting reaction(Institute of Physics Publishing michael.roberts@iop.org, 2016) Elias, L.; Damle, V.H.; Hegde, A.Ni-P alloy thin films was developed as a robust electrode material for alkaline water splitting for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), through electrodeposition technique. The influence of alloy composition, achieved through induced codeposition of the reluctant non-metal, i.e. phosphorous (P) on its electrocatalytic activity was studied, and arrived at the best composition of alloy for HER and OER. The water splitting efficacy of the alloy films was tested in 1.0 M KOH using electrochemical methods such as cyclic voltammetry and chronopotentiometry. The experimental observation shows that the alloy thin film with 9.0 wt.% of P and 4.2 wt.% of P are the best electrode materials for HER and OER, respectively. The electrocatalytic performance of alloy films towards HER and OER were related to its surface topography, composition and crystal structure through field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) analyses, respectively. © Published under licence by IOP Publishing Ltd.Item Effective role of P2O5 on in-vitro bioactivity of soda lime phosphosilicate glasses(Elsevier Ltd, 2017) Kiran, P.; Udayashankar, N.K.; Shashikala, H.D.In-vitro bio active properties have been studied on Sol-gel derived 58SiO2-33CaO-(5-X) Na2O-(4+X) P2O5 (where X=0, 5) bio glass samples soaked for seven days in a simulated body fluid (SBF) solution. X-ray diffraction studies indicated the presence of Hydroxyl Apatite (HA) crystalline phase in the synthesized samples. The spherical shaped hydroxyl carbonated apatite (HCA) nuclei were observed under scanning electron microscope. The Fourier transform infrared (FTIR) and Raman spectroscopic analysis confirmed the presence of carbonates in the glass matrix. In particular, larger concentration of P2O5 in the bioglass resulted in superior bioactivity compared to low concentration of P2O5. © 2017 Elsevier Ltd.Item Influence of Fineness of Mineral Admixtures on the Degree of Atmospheric Mineral Carbonation(Springer Science and Business Media Deutschland GmbH info@springer-sbm.com, 2021) Farsana, C.; Das, B.B.; Snehal, K.Global carbon dioxide concentration is rising at the rate of 2 ppm every year, which had led to the demand of sustainable development. In construction industry, manufacturing of cement is the main source of global anthropogenic carbon dioxide emissions. Carbon capture and storage is a recent technology which had helped to sequester carbon dioxide from atmosphere and thus helps in reducing the greenhouse effect to a certain extent. This study mainly focuses on the atmospheric mineral carbonation of mineral admixtures like fly ash (FA), ground granulated blast furnace slag (GGBS), and silica fume (SF), which are the industrial by-products and are being treated as waste. This study also focuses on the effect of fineness of different mineral admixtures on the degree of atmospheric mineral carbonation. Fly ash with three different levels of fineness (FA, FA I, and FA II), GGBS with three different levels of fineness (GGBS, GGBS I, and GGBS II), and silica fume were mixed with activators like lime and gypsum and were left for atmospheric mineral carbonation. Mineralogical characterisations were done using X-ray diffraction (XRD), thermo gravimetric analysis (TGA), and scanning electron microscopy (SEM). Degree of carbonation of the samples was analyzed and calculated using the TGA results. From the comparative analysis of all the samples, it was found that GGBS II had highest degree of carbonation. It was also observed that calcium-based compounds like calcite, aragonite, vaterite, calcite magnesium syn, gismondine, waikarite, calcium silicate hydrate, diopside, calcium sulfate, and portlandite were formed in the samples after 45 and 90 days of atmospheric mineral carbonation. However, it was observed that with increasing levels of fineness of mineral admixtures, there was no significant change in the degree of atmospheric mineral carbonation. © 2021, Springer Nature Singapore Pte Ltd.