Faculty Publications
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Item Effect of High Temperature on the Compressional Wave Velocity of Two Sandstones with Different Grain Sizes(Springer Science and Business Media Deutschland GmbH, 2024) Manikanta, V.; Hasainar, H.; Badiger, N.K.; Kothari, V.; Bhat, A.; Srinivasan, V.Understanding rock behaviour at high temperatures can serve as vital information in restoring fire-damaged monumental structures. This knowledge is essential for engineering and construction purposes, as it allows for assessing rock stability and potential hazards and developing appropriate safety measures in areas with high temperatures. This study investigates the effect of different temperatures on two sandstones with varying grain sizes. The rock was first heated to a range of temperatures such as 35, 250, 500, 750, and 1000 °C. To identify the thermal damage of the rock samples, the Ultrasonic Pulse Velocity measurement instrument is used to identify the inner cracks. This research discusses the application of Ultrasonic Pulse velocity (UPV) to identify thermal damage and analyse related parameters of two different sandstones. The ultrasonic method is one of the simple and reliable techniques to understand the damage conditions of rocks. There were significant variations in the P-wave velocity with thermal treatment, it is observed that a negative trend developed in the primary wave velocity as the temperature increased. They give qualitative and quantitative inferences on the extent of damage caused by various environmental parameters, particularly heating. The data obtained from the present study were compared to check the confidence of regression models. The mean absolute percentage error method, the root mean square error method (RMSE), was carried out on thermal damage of rock samples. Probabilistic analysis was also conducted to estimate the damage on rocks at different confidence levels. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.Item Molecular interactions of polymethyl methacrylate and polyethyeleneglycol solutions in tetrahydrofuran(2008) Muthu, M.S.; Bhat, D.K.The ultrasonic velocity, density and viscosities of the polymethylmethacrylate (PMMA) and polyethyleneglycol (PEG) solutions in tetrahydrofuran (THF) have been measured in the temperature range 293-313K. Using these data, free energy of mixing, solvation number and different polymer-solvent interaction parameters for the solution systems have been calculated to know the presence of molecular interactions in the system. The trends in the variation of the solution property parameters indicate the existence of positive molecular interactions between the polymer and the solvent in solutions. The results also show the presence of higher degree of interaction between PEG and THF in solution compared to PMMA and THF.Item Miscibility of poly(methylmethacrelate) and cellulose acetate butyrate blends in dimethyl formamide(2008) Muthu, M.S.; Bhat, D.K.The miscibility of poly(methylmethacrelate) (PMMA) and cellulose acetate butyrate (CAB) blends in dimethyl formamide (DMF) have been investigated by viscosity, density, refractive index and ultrasonic velocity studies. The 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 dimethyl formamide in the entire composition range between 303-323 K. The study also revealed that variation in the temperature does not affect the miscibility of PMMA and CAB blends in DMF significantly. The presence of hydrogen bonding in the blends in the solid state has also been indicated by FTIR studies. SEM images also supported the miscibility of blends.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 Volumetric and ultrasonic investigation of glycylglycine in aqueous FeCl3 solutions(2010) Santosh, M.S.; Bhat, D.K.; Bhat, A.S.Viscosity, ultrasonic velocity and density measurements have been carried out for glycylglycine in aqueous FeCl3 solution as a function of molality at T=288.15 K, 298.15 K and 308.15 K. The experimental data have been used to derive properties such as isentropic compressibility (? S ), change in isentropic compressibility (?? S ), relative change in isentropic compressibility (?? S /? 0), apparent molar compressibility, volume and their limiting apparent molar quantities along with the constants S K, S V and viscosity B-coefficient. The obtained thermodynamic properties have been discussed in terms of molecular interactions. © 2010 Springer Science+Business Media, LLC.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 Miscibility of poly(vinylidene fluoride) and cellulose acetate blends in dimethyl formamide(Chemical Publishing Co., 2011) Muthu, M.S.; Bhat, D.K.The miscibility of poly(vinylidene fluoride) (PVDF) and cellulose acetate blends in dimethyl formamide has been investigated by viscosity, density, refractive index and ultrasonic velocity studies. The 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 dimethyl formamide in the entire composition range between 303-323 K. The study also revealed that the variation in the temperature does not affect the miscibility of poly(vinylidene fluoride) and cellulose acetate blends in DMF significantly. The presence of hydrogen bonding in the blends in the solid state has also been indicated by FTIR studies. SEM images also supported the miscibility of blends.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.