Faculty Publications
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Publications by NITK Faculty
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Item Miscibility of polymethylmethacrylate and polyethyleneglycol blends in tetrahydrofuran(2009) Muthu, M.S.; Bhat, D.K.; Renganathan, N.G.The miscibility of polymethylmethacrylate (PMMA) and polyethyleneglycol (PEG) blends in tetrahydrofuran. (THF) has been investigated by viscosity, density, refractive index, and ultrasonic velocity studies. Various interaction parameters such as polymer-solvent and blend-solvent interaction parameters and heat of mixing have been calculated using the viscosity, density, and ultrasonic velocity data. The results indicated the existence of positive interactions in the blend polymer solutions and that they are miscible in THF in the entire composition range. The study also revealed that variation in the temperature does not affect the miscibility of PMMA and PEG blends in THF significantly. The presence of hydrogen bonding in the blends in the solid state has also been indicated by FTIR studies. © 2008 Wiley Periodicals, Inc.Item Ultrasonic velocities, densities, and viscosities of glycylglycine and CoCl2 in aqueous and aqueous ethanol systems at different temperatures(2010) Santosh, M.S.; Bhat, D.K.; Bhatt, A.S.Ultrasonic velocity (u), density (?), and viscosity (?) have been measured for glycylglycine and CoCl2 in aqueous and aqueous ethanol systems at T = (288.15 to 318.15) K. Using the experimental values, the adiabatic compressibility (?s), molar hydration number (nH), apparent molar compressibility (KS?), apparent molar volume (V?), limiting apparent molar compressibility (KS ?{symbol}0), limiting apparent molar volume (V?{symbol}0), their constants (SK, SV), viscosity coefficients of A and B parameters of Jones-Dole equation, relative viscosity (?r), and excess Gibbs free energy of activation (? G* E) were calculated and the results of all these parameters have been discussed in terms of solute-solvent and solute-solute interactions. © 2010 Elsevier Ltd. All rights reserved.Item Acoustical and compressibility parameters of glycylglycine-FeCl3 in aqueous ethanol mixture at T = (293.15, 303.15, and 313.15) K(2010) Santosh, M.S.; Bhat, D.K.Ultrasonic velocity measurement is a reliable procedure that allows quick and easy determination of solvent concentrations in mixtures. This paper presents data of ultrasonic velocities and isentropic compressibilities of (glycylglcyine-FeCl3) in aqueous ethanol mixture at T = (293.15, 303.15, and 313.15) K. Various acoustical parameters were calculated, because of their importance in the study of specific molecular interactions. A less-compressible phase of the fluid and a closer packing of molecules is observed with changes in the intermolecular free length. Quantitative investigation suggests that the mixing of ethanol with an aqueous glycylglycine-FeCl3 solution causes the rupture of hydrogen bonds, with increasing S and Lf values (where the former represents the change in isentropic compressibility and the latter represents the intermolecular free length). Theoretically computed values of isentropic compressibility in the studied mixture using different models indicate the superiority of the very complex procedure. © 2010 American Chemical Society.Item Molar volume, compressibility and excess properties of glycylglycine in aqueous NiCl2 solutions(2010) Santosh, M.S.; Bhat, D.K.Volumetric and acoustical parameters are reported for glycylglycine in aqueous NiCl2 solution at T=(288.15-318.15)K. The apparent molar volumes and isentropic compressibilities were calculated from the experimental data of ultrasonic velocity and density. Together with these, excess isentropic compressibility (?SE), excess free volume (VfE), excess intermolecular free length (LfE) and deviations of ultrasonic velocity (?u) were obtained. The results are interpreted in terms of molecular interactions. The results show that the cation and anion play a significant role in influencing the behavior of glycylglycine in aqueous solutions. These effects were also attributed to the doubly charged behavior of glycylglycine and to the formation of physically bonded ion-pairs between charged groups of glycylglycine and cation and anion of the electrolyte. © 2010 Elsevier B.V.Item Application of Prigogine-Flory-Patterson theory to volumetric, ultrasonic, and compressibility parameters of (glycylglycine + CuCl2) in aqueous ethanol mixtures(2011) Santosh, M.S.; Bhat, D.K.The molar volume and compressibility of (glycylglycine + CuCl2) in aqueous ethanol mixtures have been obtained at four different temperatures T = (288.15 to 318.15) K from ultrasonic velocity and density measurements. Excess molar volumes were found to be negative throughout the composition range indicating notable changes in hydrogen bonding and electrostatic interactions. Using the Prigogine-Flory-Patterson theory, quantitative estimation of different contributions, i.e. interactional, free volume, and P effect to VE have been obtained. The molar isentropic compressibility has been computed using the ultrasonic velocity and excess volume data. The trends in ?SE are affected by the size of the molecule leading to negative contributions. In order to compare the theoretical values of ultrasonic velocity, the equations of Nomoto and Junjie were used and found to predict the experimental data very well. © 2011 Elsevier Ltd. All rights reserved.Item Despeckling low SNR, low contrast ultrasound images via anisotropic level set diffusion(Kluwer Academic Publishers, 2014) Bini, A.A.; Bhat, M.S.Speckle is a form of multiplicative and locally correlated noise which degrades the signal-to-noise ratio (SNR) and contrast resolution of ultrasound images. This paper presents a new anisotropic level set method for despeckling low SNR, low contrast ultrasound images. The coefficient of variation, a speckle-robust edge detector is embedded in the well known geodesic "snakes" model to smooth the image level sets, while preserving and sharpening edges of a speckled image. The method achieves much better speckle suppression and edge preservation compared to the traditional anisotropic diffusion based despeckling filters. In addition, the performance of the filter is less sensitive to the speckle scale of the image and edge contrast parameter, which makes it more suitable for the detection of low contrast features in an ultrasound image. We validate the method using both synthetic and real ultrasound images and quantify the performance improvement over other state-of-the-art algorithms in terms of speckle noise reduction and edge preservation indices. © 2012 Springer Science+Business Media, LLC.Item Accurate lumen diameter measurement in curved vessels in carotid ultrasound: an iterative scale-space and spatial transformation approach(Springer Verlag service@springer.de, 2017) Krishna Kumar, P.; Araki, T.; Rajan, J.; Saba, L.; Lavra, F.; Ikeda, N.; Sharma, A.M.; Shafique, S.; Nicolaïdes, A.; Laird, J.R.; Gupta, A.; Suri, J.S.Monitoring of cerebrovascular diseases via carotid ultrasound has started to become a routine. The measurement of image-based lumen diameter (LD) or inter-adventitial diameter (IAD) is a promising approach for quantification of the degree of stenosis. The manual measurements of LD/IAD are not reliable, subjective and slow. The curvature associated with the vessels along with non-uniformity in the plaque growth poses further challenges. This study uses a novel and generalized approach for automated LD and IAD measurement based on a combination of spatial transformation and scale-space. In this iterative procedure, the scale-space is first used to get the lumen axis which is then used with spatial image transformation paradigm to get a transformed image. The scale-space is then reapplied to retrieve the lumen region and boundary in the transformed framework. Then, inverse transformation is applied to display the results in original image framework. Two hundred and two patients’ left and right common carotid artery (404 carotid images) B-mode ultrasound images were retrospectively analyzed. The validation of our algorithm has done against the two manual expert tracings. The coefficient of correlation between the two manual tracings for LD was 0.98 (p < 0.0001) and 0.99 (p < 0.0001), respectively. The precision of merit between the manual expert tracings and the automated system was 97.7 and 98.7%, respectively. The experimental analysis demonstrated superior performance of the proposed method over conventional approaches. Several statistical tests demonstrated the stability and reliability of the automated system. © 2016, International Federation for Medical and Biological Engineering.Item Agile and cost-effective ultrasonic module for people with visual impairment using a headphone jack: Implications for enhancing mobility aids(SAGE Publications Ltd, 2017) Keerthi Vasan, G.C.; Suresh, B.; Muniyandi, M.Over 80% of the world’s people with visual impairment are living in countries which are financially dire. And over 50% of them are above the age of 50 years. The need for a system or of technology that would enable this sector of people to perceive the world in much the same way as the rest of us is imminent. The article presents a novel way to eliminate the use of data acquisition system (DAQ) systems/micro-controllers by incorporating a headphone jack. With the aid of a headphone jack, a cost-effective wearable ultrasonic module that would enable people with visual impairment to virtually see is implemented. Unlike conventional walking canes or its derivatives that do not offer effective feedback, the ingenuity in the proposed module is that it offers audible feedback to the user. The ultrasonic sensor is coupled with the headphone jack and the output of the sensor is relayed to the earphones with the help of a free mobile app (Mic To Speaker). This substantially reduces the cost of the module (since no DAQs/micro-controllers are used) and the processing needed as well. © The Author(s) 2017.Item rGO/MnO2 nanowires for ultrasonic-combined Fenton assisted efficient degradation of Reactive Black 5(IWA Publishing 12 Caxton Street London SW1H 0QS, 2017) Ramesh, M.; Rao, M.P.; Rossignol, F.; Nagaraja, H.S.Reduced graphene oxide (rGO) coated manganese dioxide (MnO2) nanowires (NWs) were prepared by the hydrothermal method. Raman spectra confirmed the presence of rGO and the Brunauer-Emmett-Teller surface area of rGO/MnO2 NWs was found to be 59.1 m2g-1. The physico-chemical properties of prepared catalysts for the degradation of Reactive Black 5 (RB5) dye were investigated. 84% of RB5 dye in hydrogen peroxide solution was successfully degraded using rGO/MnO2 NWs, while only 63% was successfully degraded with pristine ?-MnO2 NWs in 60 min owing to the smaller crystallite size and large surface area. Further, the ultrasonic-combined Fenton process significantly enhanced the degradation rate to 95% of RB5 by the catalyst rGO/MnO2 NWs due to synergistic effects. The decomposition products identified using gas chromatography-mass spectrometry revealed a higher production rate of fragments in the ultrasonic-combined Fenton process. Therefore, rGO/MnO2 NWs with the ultrasonic-combined Fenton process is an efficient catalyst for the degradation of RB5, and may be used for environmental protection. © IWA Publishing 2017.Item Polystyrene-halloysite nano tube membranes for water purification(Korean Society of Industrial Engineering Chemistry A-803 Twin Bldg 275-3 Yangjae-Dong Seocho-Kul Seoul 137-130, 2018) Buruga, K.; Kalathi, J.T.; Kim, K.-H.; Ok, Y.S.; Boukhvalov, B.Membrane technologies are a sustainable solution for treatment of water and wastewater. Here, the technical feasibility of polystyrene-halloysite nanotube (PS-HNT) membranes, fabricated by an ultrasound-assisted solution casting method, was explored for water purification. To this end, the effects of various solvents on the structure, morphology, thermal, and mechanical properties of PS-HNT membranes were investigated. Introduction of HNTs (5 wt%) into the polystyrene matrix demonstrated excellent thermal and mechanical properties along with good water flux, rejection of unwanted components, recovery, and regeneration cycles. These membranes were overall useful enough to purify real wastewater collected from pulp and paper mill. © 2017 The Korean Society of Industrial and Engineering Chemistry