National Institute of Technology Karnataka

www.nitk.ac.in
Mangalore, India

The National Institute of Technology Karnataka formerly known as Karnataka Regional Engineering College , is a public engineering college at Surathkal, about 20 kilometres north of Mangalore city. It was founded in 1960 as KREC while today, it is one of the 30 National Institutes of Technology in India and is recognised as an Institute of National Importance. It has a suburban campus, in close proximity to the Arabian Sea. National Highway 66 runs through the campus and serves as the major mode of access. Wikipedia.

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Ramesh M.,National Institute of Technology Karnataka | Nagaraja H.S.,National Institute of Technology Karnataka
Materials Today Chemistry | Year: 2017

The morphology of porous silicon (PS) layers produced by electrochemical etching of n-type (100) silicon (Si) at different low current densities was studied using SEM, image J analysis and WSxM software. From FTIR spectroscopy analysis, the Si dangling bonds of the as-prepared PS layer have large amount of Hydrogen to form weak Si–H bonds. From Raman analysis, a full width half maximum (FWHM) of the Raman peak was gradually increased with increased current density, shifted towards lower energies due to reduce of crystallite size, the crystallite size in the PS varied from 63 nm to 20 nm depending on the current density. The optical response of the PS layer has been performed by the absorbance and Photoluminescence was studied experimentally in the visible range. The optical absorption and photo luminescence in PS is due to excitonic recombination between the defect states as well as on the surface of nanocrystals, and this was attributed to the presence of silicon hydride species which are confirmed by FTIR spectra. The red shift was observed in absorbance and Photoluminescence due to decrease in the size of Si crystallites and growth of Si=O bonds. The contact angle varied from 76° to 120.1°. From the wettability studies, the surface nature of the PS was converted from hydrophilic to hydrophobic when the current density increased. © 2017 Elsevier Ltd


Nechipadappu S.K.,National Institute of Technology Karnataka | R. Trivedi D.,National Institute of Technology Karnataka
European Journal of Pharmaceutical Sciences | Year: 2017

Pharmaceutical salts of BCS class II second line anti-tuberculosis drug ethionamide (ETH) with various counter ions namely, 2-chloro-4-nitrobenzoic acid (CNB), 2,6-dihydroxybenzoic acid (2,6HBA), 2,3-dihydroxybenzoic acid (2,3HBA) and 2,4-dinitrobenzoic acid (DNB) were synthesized by crystal engineering approach. All the synthesized salts were characterized by various spectroscopic (NMR, FT-IR,), thermal (DSC & TGA) and PXRD techniques. The crystal structure of the synthesized salts was determined by single-crystal X-ray diffraction techniques. All the reported salts, except ETH-2,3HBA exhibited charge assisted acid pyridine heterosynthon. In ETH-2,3HBA hydoxyl pyridine heterosynthon is observed. In ETH-CNB salt, both ionic and neutral acid pyridine heterosynthon were observed in the asymmetric unit. ETH-DNB salt consists of both partial and complete proton transfer from DNB to ETH in the asymmetric unit. All the synthesized salts were found to be non-hygroscopic at accelerated humid condition (~ 75% RH). Solubility experiment has been performed in purified water and in 0.1 N HCl (pH = 1) solution and found that the solubility of ETH-CNB salt was about eight-fold higher soluble than ETH in purified water. The solubility of synthesized salts follows the order of ETH < ETH-2,3HBA < ETH-2,6HBA < ETH-CNB in purified water. © 2016 Elsevier B.V.


Subudhi B.,National Institute of Technology Rourkela | Jena D.,National Institute of Technology Karnataka
Applied Soft Computing Journal | Year: 2011

This paper addresses the effectiveness of soft computing approaches such as evolutionary computation (EC) and neural network (NN) to system identification of nonlinear systems. In this work, two evolutionary computing approaches namely differential evolution (DE) and opposition based differential evolution (ODE) combined with Levenberg Marquardt algorithm have been considered for training the feed-forward neural network applied for nonlinear system identification. Results obtained envisage that the proposed combined opposition based differential evolution neural network (ODE-NN) approach to identification of nonlinear system exhibits better model identification accuracy compared to differential evolution neural network (DE-NN) approach. The above method is finally tested on a one degree of freedom (1DOF) highly nonlinear twin rotor multi-input-multi-output system (TRMS) to verify the identification performance. © 2010 Elsevier B.V. All rights reserved.


Raghavendra S.,National Institute of Technology Karnataka | Deka P.C.,National Institute of Technology Karnataka
Applied Soft Computing Journal | Year: 2014

In the recent few decades there has been very significant developments in the theoretical understanding of Support vector machines (SVMs) as well as algorithmic strategies for implementing them, and applications of the approach to practical problems. SVMs introduced by Vapnik and others in the early 1990s are machine learning systems that utilize a hypothesis space of linear functions in a high dimensional feature space, trained with optimization algorithms that implements a learning bias derived from statistical learning theory. This paper reviews the state-of-the-art and focuses over a wide range of applications of SVMs in the field of hydrology. To use SVM aided hydrological models, which have increasingly extended during the last years; comprehensive knowledge about their theory and modelling approaches seems to be necessary. Furthermore, this review provides a brief synopsis of the techniques of SVMs and other emerging ones (hybrid models), which have proven useful in the analysis of the various hydrological parameters. Moreover, various examples of successful applications of SVMs for modelling different hydrological processes are also provided. © 2014 Elsevier B.V.


Satyanarayan,National Institute of Technology Karnataka | Prabhu K.N.,National Institute of Technology Karnataka
Advances in Colloid and Interface Science | Year: 2011

Lead free solders are increasingly being used in electronic applications. Eutectic Sn-Cu solder alloy is one of the most favored lead free alloys used for soldering in electronic applications. It is inexpensive and principally used in wave soldering. Wetting of liquid solder on a substrate is a case of reactive wetting and is accompanied by the formation of intermetallic compounds (IMCs) at the interface. Wettability of Sn-0.7Cu solder on metallic substrates is significantly affected by the temperature and the type of flux. The wettability and microstructural evolution of IMCs at the Sn-0.7Cu solder/substrate interfaces are reviewed in the present paper. The reliability of solder joints in electronic packaging is controlled by the type and morphology of interfacial IMCs formed between Sn-0.7Cu solder and substrates. The formation and growth mechanisms of interfacial IMCs are highlighted. Mechanical behavior of bulk solder alloy and solder joint interfaces are analyzed. The characteristics of the IMCs which have marked effect on the mechanical properties and fracture behavior as well as reliability of solder joints of the alloy are discussed. An attempt has also been made to discuss the effect of cooling rate and strain rate on shear strength, tensile properties and creep resistance of the solder alloy. It is recommended that future work should focus on evolving a standard procedure involving sequential assessment of wetting behavior, evolution of IMCs and mechanical properties. © 2011 Elsevier B.V.


Khanna A.,National Institute of Technology Karnataka | Shetty V.K.,National Institute of Technology Karnataka
Solar Energy | Year: 2014

Ag core-TiO2 shell (Ag@TiO2) structured nanoparticles with Ag to TiO2 molar ratio of 1:1.7 were synthesized using one pot synthesis method and post calcination was carried out at 450°C for 3h to convert it from amorphous to crystalline form. The Ag core and TiO2 shell formation was confirmed by TEM and AFM. The particle size analysis revealed the average size of Ag@TiO2 as approximately around 30nm. EDS spectra showed the presence of O, Ag, and Ti elements. The improvement in optical properties was proved by DRS which showed significant red shift by Ag core in visible region. Ag@TiO2 exhibited better photocatalytic activity as compared to Degussa P25-TiO2, synthesized TiO2, and the Ag doped TiO2 photocatalysts under UV and solar light irradiation for degradation of Reactive Blue 220 (RB-220) dye. Higher rate of photocatalysis of RB-220 with Ag@TiO2 was obtained under solar light irradiation as compared to UV light irradiation, confirming the capability of the catalyst to absorb both UV and visible light. The kinetics of degradation of dye was found to follow modified Langmuir Hinshelwood (L-H) kinetic model. Ag@TiO2 can be recycled without much decline in the efficacy. Ag@TiO2 has been found to be the effective photocatalyst for degradation of water contaminated with azo dyes under both UV and solar light irradiations. © 2013 Elsevier Ltd.


Swaminathan K.,National Institute of Technology Karnataka | Naveenkumar D.T.,National Institute of Technology Karnataka
European Journal of Mechanics, A/Solids | Year: 2014

Analytical formulations and solutions for the stability analysis of simply supported Functionally Graded Material (FGM) sandwich plates hitherto not reported in the literature based on two higher-order refined computational models available in the literature are presented. These computational models are based on Taylor's series expansion of the displacements in the thickness coordinate and incorporate the realistic parabolic distribution of transverse strains through the plate thickness. One of them with twelve degrees-of-freedom considers the effects of both transverse shear and normal strain/stress while the other with nine degrees-of-freedom includes only the effect of transverse shear deformation. In addition another higher-order model and the first-order model developed by other investigators and available in the literature are also considered for the evaluation purpose. For mathematical modeling purposes, the Poisson's ratio of the material is considered as constant whereas Young's modulus is assumed to vary through the thickness according to the power law function. The governing equations of equilibrium for buckling analysis are obtained using the Principle of Minimum Potential Energy (PMPE). Solutions are obtained in closed form using Navier's technique by solving the eigenvalue problem. The comparison of the present results with the available elasticity solutions and the results computed independently using the first-order and another higher-order theory available in the literature shows that the higher-order refined theory with 12 degrees-of-freedom predicts the critical buckling load more accurately than all other theories considered in this paper. After establishing the accuracy of prediction, extensive numerical results for FGM sandwich plates using all the models are presented which will serve as a benchmark for future investigations. © 2014 Elsevier Masson SAS. All rights reserved.


Suhasini,National Institute of Technology Karnataka
Journal of Electroanalytical Chemistry | Year: 2013

Manganese dioxide has been considered as a promising material for electrochemical supercapacitors. In order to obtain a high specific capacitance, MnO2 has been electrodeposited from an aqueous acidic solution of MnSO4 consisting of an ionic surfactant, namely, sodium lauryl sulphate (SLS) on stainless steel. The electrodeposited films of MnO2 in the presence of the surfactant possess greater porosity and hence greater surface area in relation to the films prepared in the absence of the surfactant. Cyclic voltammetry and galvanostatic charge-discharge cycling experiments reveal that specific capacitance is higher by about 22% due to the effect of SLS. © 2012 Published by Elsevier B.V.


Shivashankar R.,National Institute of Technology Karnataka | Jayaraj J.,LBS Institute of Technology for Women
Geotextiles and Geomembranes | Year: 2014

The effects of prestressing the reinforcement on the strength improvement and settlement reduction of a reinforced granular bed overlying weak soil are being investigated through a series of laboratory scale bearing capacity tests. The influences of parameters such as strength of underlying weak soil, thickness of granular bed, magnitude of prestressing force, direction of prestressing forces and number of layers of reinforcement are being examined. Finite element analyses are carried out using the FE program PLAXIS to study the effect of prestressing the reinforcement. Results obtained from finite element analyses are found to be in reasonably good agreement with the experimental results. © 2013 Elsevier Ltd.


Narayani M.,National Institute of Technology Karnataka | Shetty K.V.,National Institute of Technology Karnataka
Critical Reviews in Environmental Science and Technology | Year: 2013

The anthropogenic inputs of hexavalent chromium [Cr(VI)] have increased enormously during the past few decades and has become a challenge for life on earth and hence removal of this carcinogen has become the need of the hour. Cr(VI) removal through common physicochemical techniques is highly expensive and inappropriate at low concentration. Microbial reduction of Cr(VI) to trivalent form is considered a favorable technique for Cr(VI) removal from wastewater, as it reduces the highly toxic form of Cr to less toxic form and therefore the article conveys essential fundamental information on removal of Cr(VI) by bacteria. For efficient bioremoval of Cr(VI),the main machinery of the process, the microbes, and their conditions, which decide the fate of this heavy metal, should be appropriate. Hence, the authors cover vast information about the isolation of chromium-resistant bacteria from various environment and their Cr(VI) resistance capability. An extensive report is given on information pertaining to the factors such as cell density, pH, temperature, salt concentration, oxidation-reduction potential, electron donor, oxyanions, metabolic inhibitors, and other heavy metals that influence or affect the efficient Cr(VI) removal. Cr(VI) removal by immobilized bacterial cells and their advantages has also been summarized. In transferring this technology from laboratory to a large-scale application, better understanding of all these aspects is necessary. Hence, this developing biotechnological method that encompasses fields from genetic engineering to reactor engineering demands focused research in these directions, which may lead to implementation of this technology on a larger scale and drive it toward being the most opted-for technology. © 2013 Copyright Taylor and Francis Group, LLC.

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