Papers by Keyword: Ultrasonic Velocity

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Authors: S. Rajagopalan, S.J. Sharma, V.Y. Nanotkar
Abstract: In the present work, ultrasonic velocity measurements have been carried out in solutions of silver nanoparticles in the polymer matrix of poly(sodium, 4-styrene sulphonate) using Sing-Around technique, operated at 2 MHz.. The ultrasonic velocity of propagation shows an abnormal behaviour, indicating the existence of the phase separations in nano-colloidal solution. The effect of polymer is observed to be predominant in the phase separation at the lower concentrations of polymer in the mixture. At higher concentrations of the polymer in the mixture the phase separation seems to subside at higher temperature.
Authors: Masahiko Matsubara, A. Nitta, S. Sakai, N. Fujinawa
Authors: Selvi C. Senthamil, S. Ravichandran, C.P. Malliga, C. Thenmozhi, V. Kannappan
Abstract: Ultrasonic velocity and density of salicilaldehyde with iodine in hexane has been measured at 293.15K, 298.15K, 303.15K and 308.15K in different concentration. Ultrasonic velocity has been measured using single frequency interferometer at 2MHz (Model F-81). By using the Ultrasonic velocity (u), density (ρ) and coefficient of viscosity (η) and the other acoustical parameters adiabatic compressibility (κ), free length (Lf), interaction parameter (α), Free volume (Vf) were calculated. The addition of hexane with a mixture leads to a compact structure due to presence of dipolar type interaction. This contributes to the decrease in free volume values and the internal pressure shows an increasing trend. The results have been discussed in terms of solute-solute and solute-solvent interactions between the component and the compatibility of these methods in predicting the interactions in these mixtures has also been discussed.Key Words salicilaldehyde, iodine, hexane, Ultrasonic velocity, molecular interactions.
Authors: B. Rohini, Solomon Jeevaraj A. Kingson
Abstract: Ultrasonic parameters of CuO: Diethylamine-Isopropaonol binary nanofluids at six different concentrations have been reported at three different temperatures like 298K, 308K and 318K. The acoustical parameters such as Ultrasonic sound velocity (v), Compressibility (β), Inter molecular free length (Lf), Acoustic impedance (Z) are calculated from experimental data. The variation of these parameters with composition of the mixture helps us in understanding the nature and extent of interaction between particles and the binary liquid mixtures. Keywords Ultrasonic velocity, Compressibility, Acoustic impedance, Inter molecular free length, Nanofluids
Authors: Min Liu, De Ping Chen, Jing Yu Liu
Abstract: Carbon dioxide curing was adopted to accelerate the hydration of foam concrete samples with a lower bulk density level of around 450 kg/m3 and a higher level of around 1150 kg/m3. The bending strength, compressive strength and ultrasonic transmission velocity of carbonated harden foam concrete were tested, the hydration products were analyzed by means of XRD and TG/DSC. The results show as: (1) By comparing with standard curing samples, there are more than 47% increments of specific strengths of carbonated foam concrete with the higher density level at a certain curing time before 14d. However, for the lower density level one, there is just a significant improvement of specific bending strength obtained before 7d. (2) The carbonated foam concretes with the lower density level show lower ultrasonic transmission velocity than standard curing ones. The velocities have hardly difference for both carbonated and standard curing samples with the higher density level. (3) Vaterite can’t be found in carbonated foam concrete with the lower density level at curing time before 28d, while it becomes a common phase in 3d’s carbonated sample with the higher density level. Vaterite was considered to be an important factor that influences the ultrasonic transmission velocity.
Authors: Takeshi Fukami, M. Fukatani, Daisuke Okai, Tohru Yamasaki, Osami Haruyama, Akihisa Inoue
Abstract: In order to examine the correlation between a mechanical property and an excess free volume for metallic glass Pd44Cu31Ni8P17, longitudinal and transverse ultrasonic velocities were measured to estimate longitudinal and transverse elastic constants, c11 and c44. An as-quenched sample, an annealed one at a temperature just below a glass transition temperature Tg and a crystalline one were prepared. The as-quenched sample contains the excess free volume depending on the preparing process. The Young’s modulus E, the Poisson’s ratio, a bulk modulus and c12 are estimated using c11 and c44. The values of c11, c 44 , c12 and E of the as-quenched one are smaller than those of the annealed sample losing excess free volume by about 0.2 % and much smaller than those of the crystalline one. The Poisson’s ratio for the as-quenched sample and the annealed one are 0.389 and 0.387, respectively, which are much larger than that for the crystalline one with 0.349.
Authors: Jing Zhou Lu, Lin Chen, Xu Zhu, Na Xu, Gao Lin
Abstract: An experimental study of the damage behavior of two kinds of concrete with different strength grades has been performed using 100mm cubes subjected to increasing hydrostatic loading history, namely, the isotropic compression at high pressure. The compressive strength and ultrasonic velocity are measured before and after loading history, respectively. The damage degree of these cubes is defined as the reduction of compressive strength based on the continuum damage mechanics theory. Linear and exponential curve fit of experimental data is performed respectively to describe the evolution of damage as well as the descent of ultrasonic velocity with respect to the loading history. It can be seen that, the influence of hydrostatic loading history upon strength and ultrasonic velocity could really reflect that upon the degree of damage development. In general, ultrasonic inspection is convenient and applicable to estimation of damage of concrete due to loading history in engineering practice.
Authors: P. Palanichamy, M. Sivabharathy, K. Jeyadheepan, P. Kalyanasundaram, K. Ramachandran, C. Sanjeeviraja
Abstract: Alloy D9 is a candidate material for core components of fast breeder reactors. This alloy has been 20% cold worked and thermally aged at 1073 K for different time durations and their thermal properties have been studied using photoacoustic (PA) measurements. The results of the PA measurements have been correlated well with the ultrasonic velocity and hardness measurements.
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