Values Of Sound Velocity Research Articles

Estimation of Theoretical Sound Velocity in the (Bio-Ternary) Liquid Systems (α-amylase + Galactose) at 298.15 K

Various theoretical models have been applied to evaluate the sound velocity values at 298.15 K for the ternary system of galactose with aqueous amylase and compared with experimental values. The validity of Nomoto (NR), Van Deal-Vangeal (IMR), Impedance dependence relation (IDR), Collision factor theory (CFT) and Nutsch-Kuhnkies (NK) methods is checked and a comparative study of these models is made. The non-ideal behavior of the systems is explained in terms of molecular interactions of the constituents of the mixture.

Does there exist an anomalous sound dispersion in supercooled water?

The acoustic sound velocity of water in the supercooled regime shows peculiar behaviour. According to the available data, the sound velocity displays complex behaviour below −15°C, where anomalous frequency dispersion phenomena seem to appear and need to be understood. In particular, lower-frequency data at a few tens of KHz show levelling-off of the sound velocity value below −25°C, with a possible minimum around −30°C. Other data at higher frequencies, around 1 GHz, in comparison with the low-frequency data, could instead suggest the existence of a ‘negative dispersion’; yet other high-frequency data show normal dispersion behaviour. To gain new insight into this topic, we made measurements of the acoustic sound velocity in bulk water in the liquid and supercooled phase down to −29°C by means of a heterodyne detected transient grating (TG) experiment at an unexplored frequency value around 100 MHz.

Macroscopic elastic anisotropy in tough ceramics from the single crystal elastic behaviour

The modern techniques for engineering analysis are based on a deep understanding of the proportional relationship between stress and strain and the description in terms of isotropic elastic constants, in many cases, is enough. In anisotropic materials the knowledge of the elastic constants is important for the manufacturing process and for micro mechanical modelling behaviour of the material to develop the new composite materials. Theoretical calculations of elastics constants and anisotropies are applied to tough ceramics ZrO2, HfO2 and in rutile TiO2 and SnO2. Their dependence of the residual hydrostatic stress in the crystal are given. The microscopic elastic anisotropy determined in this work, could be applied in the macro scale in the case the constituent grains have a preferred orientation in the crystal lattice or the grains shape is not spherical (faceted) and it is aligned to a common crystal axis. To cover the case where the grains are distributed at randomly, the Voigt-Reuss-Hill polycrystalline approach is applied to obtain the average values of Young, bulk, shear modules, Poisson coefficient and sound velocity in the transversal and longitudinal modes. These theoretical results, could be useful in the interpretation of experimental results obtained with the method known as diffraction elastic constant (DEC).

Evaluation of Sound Speed for Detection of Liver Fibrosis

The degree of liver fibrosis determines the prognosis and treatment of patients with chronic viral hepatitis. Transient elastography (TE) has been accepted as a noninvasive method for assessment of liver fibrosis. Sound velocity (SV) changes are also dependent on elastic properties of tissue. The aim of this pilot study was to evaluate whether SV estimation of liver tissue allows the determination of fibrosis stages in patients with chronic viral hepatitis. Prospectively, 50 healthy volunteers and 149 patients received stiffness (TE, 50-Hz vibrator, 5-MHz array) and SV (conventional ultrasound, C5-2-MHz transducer) measurements. Eighty-four patients received representative liver biopsies. The estimated SV and stiffness were compared using liver biopsy as a reference (METAVIR fibrosis stage [F] scoring system [Hepatology 1996; 24:289-293]). Descriptive statistics, analysis of variance, receiver operating characteristic curve analysis, and box plot analysis as well as intra-operator and interoperator reproducibility analyses were performed. The SV ranged from 1540 to 1650 m/s. The mean SV ± SD was significantly different between healthy volunteers (1559 ± 11 m/s) and patients with F0-F3 (1575 ± 21 mm/s) and F4 (1594 ± 18 m/s) disease (P < .001). For detection of liver cirrhosis, the area under the receiver operating characteristic curve for SV was 0.80 (95% confidence interval, 0.69-0.89). With a cutoff value of 1589 m/s, the sensitivity, specificity, and positive and negative predictive values of SV for detection of liver cirrhosis were 82%, 76%, 70%, and 86%, respectively. Sound velocity measurements were reproducible (15%) and had acceptable operator independence (19%). The SV of liver tissue depends on the fibrosis stage. An SV of 1589 m/s or higher detects cirrhosis with high sensitivity. Therefore, SV measurement appears to be a promising new method for noninvasive quantification of liver fibrosis.

Molecular Interactions in Binary Mixture of Polymethylmethacrylate with Acetic Acid

Solution is prepared by mixing Polymethylmethacrylate in solid form with acetic acid, which at differentconcentration were used to measure density, viscosity & ultrasonic velocity in the temperature range 300C-650C,using ultrasonic interferometer at 1MHz. Using these measured values of density, viscosity & sound velocity,different parameters like, adiabatic compressibility, acoustic impedance and relaxation time have been measuredfor solution of polymethylmethacrylate with acetic acid under different conditions of temperature andconcentration. Variations of above parameters with respect to temperature and concentration have beendiscussed in terms of molecular interactions.

Predictions for the Sound Velocity in Various Liquid Metals at Their Melting Point Temperatures

Sound velocity values for 32 liquid metals at their melting point temperatures have been predicted using two models that we presented; most of these metals are transition and rare earth metals. The sound velocities for most of these liquid metals have yet to be measured experimentally. Dimensionless common parameters, denoted by $$ \xi_{\text{T}}^{1/2} $$ and $$ \xi_{\text{E}}^{1/2} , $$ were determined on the basis of the predicted sound velocities. These common parameters, which characterize the liquid state (i.e., an atom’s hardness or softness and its anharmonic motions), allow for better predictions of several thermophysical properties (e.g., surface tension, viscosity, self-diffusivity, volume expansivity) of liquid metallic elements. The values of both the common parameters $$ \xi_{\text{T}}^{1/2} $$ and $$ \xi_{\text{E}}^{1/2} $$ vary periodically with atomic number. Using our viscosity model in terms of the parameter $$ \xi_{\text{T}}^{1/2} , $$ values of melting point viscosity were calculated for liquid molybdenum and platinum. The agreement obtained between calculated and experimental values is good when using predicted values of $$ \xi_{\text{T}}^{1/2} $$ to calculate their viscosities.

Predictive Models for the Velocity of Sound in Liquid Metallic Elements at Their Melting-Point Temperatures

Nowadays, accurate and reliable data for the thermophysical properties of almost all liquid metallic elements are indispensable in the field of materials process science (e.g., for computer simulation studies of the fluid flow in a vessel or the solidification of a metallic element). The dimensionless common parameters (denoted by ξ 1/2 and ξ 1/2 ), extracted from the velocity of sound, provide for better predictions of the thermophysical properties of liquid metallic elements such as surface tension, viscosity, self-diffusion, thermal expansion, and evaporation enthalpy, because these two parameters characterize the state of the liquid metallic atom (i.e., an atom’s hardness or softness and its anharmonic motions). The usefulness of reliable predictive models in many engineering situations is clear; in the field of materials process science and engineering, both “accuracy” and “universality” are required of any model for predicting the thermophysical properties of liquid metallic elements. In view of the accuracy and universality of a model, predictive models for the velocity of sound in liquid metallic elements at their melting-point temperatures were investigated; the performances of several models were evaluated by comparing experimental values for the melting-point sound velocity in various liquid metallic elements with those calculated from these models, using a relative standard deviation as a yardstick. Of these, two simple models in terms of well-known physical quantities, presented by the authors, give very good agreement with the experimental data. Excluding only a few metals, calculated sound-velocity values fall, or almost fall, within the range of uncertainties associated with experimental measurements of high-melting-point or reactive metals. It can safely be said that the two models for melting-point sound velocity in liquid metallic elements are endowed with the necessary conditions of being predictive.

Elastic Properties of Potassium Borate Glass in a Wide Composition Range Studied by Brillouin Scattering

The elastic properties of potassium borate glass, xK2O·(100 - x)B2O3, where x is the molar composition of K2O in mol %, have been investigated by Brillouin scattering spectroscopy over a wide composition range of 2 ≤x ≤42 mol %. From the observed values of longitudinal sound velocity, the elastic constant has been determined and compared with that of lithium borate glass. The sound velocity increases with increasing x below x = 30; however, for a further increase in x, it decreases owing to the softening caused by the formation and increase in the number of nonbridging oxygen atoms. The absorption coefficient also increases markedly above x = 30 owing to the scattering of acoustic waves by nonbridging oxygen atoms. The temperature dependences of both sound velocity and absorption coefficient of 14K2O·86B2O3 show a markedly change at approximately the glass transition temperature Tg of 395 °C.

Role of aniline in destructing the 1-propanol + toluene azeotrope

The separation of azeotropes is a major task in petrochemical industries. The role of aniline in destructing the toluene–1-propanol azeotrope is analyzed in the present work. Sound velocity and density values have been measured at 303 K in the binary and ternary systems containing aniline, 1-propanol, and toluene. From these data, adiabatic compressibility and its excess values have been estimated and used as the key parameter to analyze the ternary situation that exists in the system. The results are interpreted in terms of molecular interaction between the components of the mixtures that can ascertain the role of aniline in this process.

Effect of toluene in the dipolar interaction of some aliphatic alcohols

Sound velocity, density and viscosity values have been measured at 303 K in the three binary systems of toluene + methanol, ethanol, 1-propanol. From these data, acoustical parameters such as adiabatic compressibility, free length, free volume and internal pressure have been estimated using the standard relations. The results are interpreted in terms of molecular interaction between the components of the mixtures. Observed excess value in all the mixture indicates that the molecular symmetry existing in the system is highly disturbed by the non-polar toluene molecules and dipole–dipole type interactions exist in the systems.

Ultrasonic analysis in the ternary system of pyridine+benzene+2-butanol

Abstract The ternary situation in liquid mixtures is always associated with the functional group, the geometry and the polarity of the component molecules. The inherent nature of the functional group of 2-butanol that facilitates its separation in petrochemical industries is analyzed in this work. Sound velocity and density values have been measured at 303 K in the binary and ternary systems having pyridine, 2-butanol and benzene. From these data, adiabatic compressibility and its excess values have been estimated and used as the key parameter to analyze the ternary situation that exists in the system. The excess parameters are fitted to polynomial type Redlich–Kister and Cibulka equations and the coefficients of the fitting are found to support the present investigations.

The van der Waals gas EOS for the Lorentz contracted rigid spheres

The relativistic equation of state (EOS) of the van der Waals gas is suggested and analyzed. In contrast to the usual case, the Lorentz contraction of the sphere's volume is taken into account. It is proven that the suggested EOS obeys the causality in the limit of high densities, i.e., the value of sound velocity of such a media is subluminar. The pressure obtained for the high values of chemical potential has an interesting kinetic interpretation. The suggested EOS shows that for high densities the most probable configuration corresponds to the smallest value of the relativistic excluded volume. In other words, for high densities the configurations with the collinear velocities of the neighboring hard core particles are the most probable ones. This, perhaps, may shed light on the coalescence process of any relativistic hard core constituents.

Crossover between hydrodynamic and kinetic modes in binary liquid alloys

Inelastic x-ray scattering (IXS) measurements of the dynamic structure factor in liquid Na57K43, sensitive to the atomic-scale coarse graining, reveal a sound velocity value exceeding the long wavelength, continuum value and indicate the coexistence of two phonon-like modes. Applying Generalized Collective Mode (GCM) analysis scheme, we show that the positive dispersion of the sound velocity occurs in a wavelength region below the crossover from hydrodynamic to atom-type excitations and, therefore, it can not be explained as sound propagation over the light specie (Na) network. The present result experimentally proves the existence of positive dispersion in a binary mixture due to a relaxation process, as opposed to fast sound phenomena.

Effect of Isomerism in the Dipolar Interaction of Benzene with Butanol

Sound velocity, density, and viscosity values were measured at 303 K in four binary systems of benzene + 1-, 2-, tert-, or iso-butanol. From these data, acoustical parameters, such as adiabatic compressibility, free length, free volume, and internal pressure were estimated using the standard relations. The results are interpreted in terms of molecular interaction between the components of the mixtures. Observed excess value in all the mixture indicates that the molecular symmetry existing in the system is highly disturbed by the nonpolar benzene molecules. Interaction energy terms of the statistical mixing are also verified for these binary systems and the dipole-dipole interactions are found to be predominantly present and are sharply affected by the isomeric forms of butanol.

Evaluation of the efficiency of consolidants on Hungarian porous limestone by non-destructive test methods

Abstract Three types of porous limestone from Soskut quarry and two limestone types obtained directly from Matthias Church of Budapest (both in Hungary) were used to test the performance of five stone consolidants. The quarry specimens were treated under laboratory conditions by saturation. Three types of silicic acid ester, an aliphatic uretan resin and a polymethyl methacrylate were applied to the stone. Physical parameters such as density, porosity, ultrasonic sound velocity and Duroscope rebound value were measured on untreated and treated samples. The absorption rate of different consolidants was also detected. The physical properties of untreated and treated specimens were compared in order to analyze the performance of the consolidants. Duroscope tests have shown that after consolidation there is an increase in surface strength.

Ultrasonic investigation of molecular association in binary mixtures of aniline with aliphatic alcohols

Abstract Sound velocity, density and viscosity values have been measured at 303 K in the three binary systems of aniline + methanol, ethanol and 1-propanol. From these data, acoustical parameters such as adiabatic compressibility, free length, free volume and internal pressure have been estimated using the standard relations. The results are interpreted in terms of molecular interaction between the components of the mixtures. Observed excess value in all the mixtures indicates that the molecular symmetry existing in the system is highly disturbed by the polar alcohol molecules' dipole–dipole and induced dipole–dipole type interactions that are existing in the systems.

Sound propagation in a highly damped Mo6S3I6 nanowire network measured by femtosecond pump-probe spectroscopy

Using femtosecond pump-probe spectroscopy we have measured the propagation of sound in a randomly formed Mo6S3I6 nanowire network for the first time. The pump-probe technique allows us to measure the reflection of an optical pulse from a propagating acoustical disturbance in spite of very high sound damping in the rather porous network medium. We use a range of different laser wavelengths from 0.7 to 2.4 μm and a measurement of the refractive index n, to obtain a value of sound velocity v=1630±160 m∕s.

Ultrasonic Analysis of the Degree of Cure and Cohesive Properties of the Adhesive in a Bond Joint

Acoustic techniques have been used to monitor cure of thermoset adhesive during cure reaction and to evaluate cohesive properties of the material in the adhesive joint after cure. Longitudinal sound velocity and attenuation as well as adhesive's elastic moduli were monitored to investigate molecular network development during reaction at different temperatures. The ability of high-resolution acoustic microscopy to study development of adhesive microstructure during cure reactions was also demonstrated. Correlations of the value of sound velocity with cohesive properties of the material and with joint performance were demonstrated. This approach can be used to monitor development of the cohesive strength of the joint during the cure process in manufacturing.

Excess value studies in the mixture of aniline + 1-propanol + benzene

Sound velocity, density, and viscosity values have been measured at 303 K in the ternary system of aniline + 1-propanol + benzene. From these data, acoustical parameters such as adiabatic compressibility, free length, free volume, and internal pressu

The effects of oxygen partial pressure on the acoustic velocity in zirconia films studied by picosecond ultrasonics

We have performed a picosecond ultrasonic study of the effects of oxygen partial pressure on the acoustic velocity in zirconium oxide films made by radio frequency reactive sputtering. To derive more accurate and reliable values of sound velocity, various reflective layers were used to enhance the echo signals of acoustic pulses photoexcited by an ultrafast laser. It is found that the acoustic responses of the samples with a W reflective layer are much stronger than those with a Si or SiO 2 reflective layer. In addition, the W reflective layer generates extra photoacoustic waves, which can be utilized to improve the accuracy of velocity measurement. The thin film velocities we measured were 10∼24% less than the bulk value, and exhibited a strong dependence on the growth conditions and the microstructure of films.