Ultrasonic Properties in Au Nanoparticles Reinforced PVA Solution (original) (raw)

Sensitivity of Nanostructured Iron Metal on Ultrasonic Properties

The present investigation is focused on the influence of the nanocrystalline structure of pure iron metal on the ultrasonic properties in the temperature range 100 -300 K. The ultrasonic attenuation due to phononphonon interaction and thermoelastic relaxation phenomena has been evaluated for longitudinal and shear waves along <100>, <110> and <111> crystallographic directions. The second-and third-order elastic constants, ultrasonic velocities, thermal relaxation, anisotropy and acoustic coupling constants were also computed for the evaluation of ultrasonic attenuation in this temperature scale. The direction <111> is most appropriate to study longitudinal sound waves, while <100>, <110> direction are best to propagate shear waves due to lowest values of attenuation in these directions. Other physical properties correlated with obtained results have been discussed.

Ultrasonic Properties of Nanoparticles-liquid Suspensions

A polymer colloidal solution having dispersed nanoparticles of Cu and Au metals have been developed using a novel chemical method. Average size of the nanoparticles could be varied in the 4-10 nm range by conducting the reaction at an elevated temperature of 50-70°C. Colloidal solutions of representative concentrations of 0.1-2.0 wt% Cu/Au contents in the primary solutions are used to study the modified ultrasonic attenuation and ultrasonic velocity in PVA polymer molecules on incorporating the Cu/Au particles. A characteristic behaviour of the ultrasonic velocity and the attenuation are observed at the particular temperature/particle concentration. The results demonstrate that the primary reaction during the nanoparticles-PVA colloidal formation occurs in divided groups in small micelles. The results are analyzed predicting the enhanced thermal conductivity of the samples.

Ultrasonic Properties of Composites of Polymers and Inorganic Nanoparticles

Phys. Status Solidi A , 2013

The temperature dependencies of ultrasonic velocity and attenuation were measured in composites of inorganic nano-particles with two types of polymers, poly(urea) elastomer with inorganic Mo6S4I6nanowires and poly(e-caprolactone) (PCL)with Mo6S3I6nanowires. Below room temperature large ultrasonic relaxation attenuation maxima and velocity dispersion were observed. It was found that the attenuation peak in the elastomer shifted to higher temperatures after doping with nanoparticles and this behavior was related to the shift of glass transition temperature. The ultrasonic attenuation data were fitted to a relaxation equation with single temperature-dependent relaxation time. The thermal activation energy of the relaxation process, which was calculated from ultrasonic data, was found to increase in the poly(urea) elastomer doped with MoSI nanowires. The low-temperature ultrasonic velocity increased in the poly(urea) with nanowires added and is determined by the increase in elastic modulus. Similarultrasonic behavior was obtained for PCL composites with inorganic MoSI nanowires. In this case, the increase in elastic modulus was smaller in comparison to the composites of poly(urea) and nanowires. Therefore, the reinforcement of PCL was less pronounced.

Study of some mechanical and rheological properties of PVA/FeCl3 by ultrasonic

In this study some of the physical properties of polyvinyl alcohol dissolves in distilled water with different concentration (0.143%, 0.286%, 0.429%, 0.572%, and 0.715%) before and after mixing the appropriate amount of FeCl3 with aqueous PVA solutions, the Rheological properties such as shear viscosity, relative viscosity specific viscosity and reduced viscosity are measured, after that the ultrasonic velocity had been measured at frequency (40KHz). Other mechanical properties had been calculated such as absorption coefficient of ultrasonic waves, relaxation time, relaxation amplitude, specific acoustic impedance, bulk modules and compressibility. The results show that all these properties are affected with variation in density and viscosity because of the intermolecular interactions and network formation between the two types of molecules and the changes in wave pressure causes molecules to flow into vacancies in the lattice during compression phase and to return to their original positions in the lattice during rarefaction.

Study of some mechanical properties of PVA/TiO 2 composite at different ultrasonic frequencies

The PVA/TiO 2 composite polymer membranes were prepared by a sol-Gel casting method, the weight of PVA is constant (1gm) while the TiO 2 powder weights were (0.01, 0.02, 0.03, 0.04, 0.05) gm, the density of the samples were measured by the weight method. In order to evaluate the mechanical properties of PVA/TiO 2 composite the ultrasonic measurements were performed at the composites these properties are ultrasonic velocity, compressibility, acoustic impedance and bulk modulus at different frequencies (25,30,35,40) kHz , another acoustic mechanical properties were measured and calculated at a same time such as the ultrasonic wave amplitude before and after absorption by composite were measured using oscilloscope, then we calculated absorption coefficient and transmittance, shear viscosity , relaxation time and relaxation amplitude. It was found that there is significant relationship between ultrasonic velocity and material properties also results show that adding TiO 2 effect on the absorption of the ultrasonic waves inside the composites.

Effect of Platinum Addition to Coinage Metals on Their Ultrasonic Properties

Platinum Metals Review, 2010

Ultrasonic attenuation for the longitudinal and shear waves due to phonon-phonon interaction and due to thermoelastic relaxation mechanisms have been evaluated in bimetallic alloys of the coinage metals (copper, silver or gold) with 1, 2, 3 or 4 at% platinum.The evaluations were carried out along the 〈100〉, 〈111〉 and 〈110〉 crystallographic directions at room temperature. Second-and third-order elastic constants, ultrasonic velocities and thermal relaxation times have also been computed for these alloys. In each case, the addition of platinum to the coinage metal reduces the attenuation, which indicates that bimetallic alloys with a higher platinum content are more ductile and stable and contain fewer defects in their crystal structure than those with a lower platinum content. The predominant mechanism of attenuation of ultrasonic waves is phonon-phonon interaction rather than thermoelastic loss. The results are compared with available theoretical data and experimental measurements for the pure coinage metals.These results, in combination with other well-known physical properties, can be applied to the non-destructive testing of materials for various industrial applications.

Investigation of Stress and Temperature Effect on the Longitudinal Ultrasonic Waves in Polymers

Research in Nondestructive Evaluation, 2014

This work aims at establishing the effect of stress and temperature on the velocity of ultrasonic longitudinal waves in typical engineering polymers, and evaluating the potential of ultrasonic stress measurement in the evaluation of residual stresses in polymer parts. In order to estimate the effect of material morphology, two amorphous and two semicrystalline polymers have been considered. A series of tests are implemented, to determine the acoustoelastic constants and temperature constant of materials, by using the designed transducer fixtures for in situ measurement of longitudinal wave velocity. As expected, the velocity changes linearly with stress and temperature, and the temperature effect is as important as the acoustoelastic effect. It shows that this kind of nondestructive method is a valuable quantitative tool to estimate the residual stress in polymer products, but the material temperature influence must be considered during the estimation.

Ultrasonic Attenuation in Polycrystalline 5N Aluminium

Le Journal De Physique Colloques, 1987

The ultrasonic attenuation of 5N purity polycrystalline aluminium has been measured over the temperature range from 110 to 300K at a frequency of 10 MHz, using a conventional pulse echo technique with a single quartz transducer. Five specimens were used and each was subjected to a series of deformations by compression, the plastic strain ranging up to about 20%. For the higher deformations two dislocation relaxation peaks (Bordoni and Niblett-Wilks peaks) were observed at about 226 and 168K respectively, superimposed on attenuation due to other sources. The Bordoni peak was not observed after low levels of deformation, only the Niblett-Wilks peak being evident at these strains. Our results are compared with previous measurements on similarly-strained 5N aluminium at other frequencies and indicate that the activation energies for the Bordoni and Niblett-Wilks peaks are about 0.22 and 0.15 eV respectively.

Temperature dependent ultrasonic properties of aluminium nitride

Applied Acoustics, 2009

Hexagonal wurtzite structured aluminium nitride has been characterized by the theoretical calculation of ultrasonic attenuation, ultrasonic velocity, higher order elastic constants, thermal relaxation time, acoustic coupling constants and other related parameters in temperature range 200–800 K for wave propagation along the unique axis of the crystal. Higher order elastic constants of AlN at different temperatures are calculated using Lennard-Jones potential for the determination of ultrasonic attenuation. A decrease in ultrasonic velocity with temperature has been predicted, which is caused by reduction in higher order elastic constants with temperature. The temperature dependent ultrasonic properties have been discussed in correlation with higher order elastic constants, thermal relaxation time, thermal conductivity, acoustic coupling constants and thermal energy density. Anomalous behaviour of the attenuation is found at 400 K. On the basis of attenuation, the ductility and performance of AlN have been studied.

Acoustic properties of alumina colloidal/polymer nano-composite film on silicon

IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 2000

Alumina colloidal/polymer composite films on silicon substrates have been successfully fabricated using the sol-gel method, in which the crystallite sizes of alumina are between 20 and 50 nm. The density and ultrasonic phase velocities in these films with different alumina ratios from 14% to 32% were measured at the desired operating frequency. We have proved that the density, acoustic phase velocities, and hence the acoustic impedance of the nanocomposite films increase with the alumina content, which gives us another option of tailoring the acoustic impedance of the nano-composite film for making the matching layer of high-frequency medical ultrasonic transducers.