Influence of the applied pressure of the transducer on the propagation speed of the ultrasonic wave in wood

The non-destructive wave propagation technique is used to estimate the wood’s modulus of elasticity. The propagation speed of ultrasonic waves is influenced by some factors, among them: the type of transducer used in the test, the form of coupling and the sensitivity of the transducers. The objective of the study was to evaluate the influence of the contact pressure of the transducers on the ultrasonic speed. Ninety-eight tests were carried out on specimens of the species Eucalyptus grandis, with dimensions of 120 × 120 × 50 mm. The calibration of the pressure exerted by the transducer was controlled by a pressure gauge using a previously calibrated load cell. The robust statistical analysis allowed to validate the experimental results and to obtain consistent conclusions. The results showed that the wave propagation speed is not influenced by the pressure exerted by the transducer.

Ultrasonic Investigation of Binary Solutions of Petrolium And Its Products

<p>Experiment values of densities and ultrasonic speed of petroleum product Gasoline (Petrol) and 2T Oil were taken in different volume concentrations from 5%, 10%------, and 95% at different temperatures from 298.15K to 318.15K having difference of 5K. From the experimental data, Apparent Molar Compressibility (<em>ϕ_K</em>), Relative Association (<em>R_A</em>), Solvation Number (<em>S_n</em>), Free Energy of Activation (<em>ΔE</em>), Excess Adiabatic Compressibility (<em>β_ad^E</em>), Excess Volume (<em>V^E</em>), Excess Free Length (<em>L_f^E</em>) have been computed. These parameters are used to focus light on the nature of component molecules of binary liquids and the excess functions are found to be sensitive to the nature and extent of the intermolecular interactions taking place in these binary mixtures.</p>

Evaluation of Thermodynamic and Optical Properties of Sixteen Ionic Liquids at Different Temperature

Based on the dimensional analysis ρ-u- thermodynamic and ρ-u- optical properties correlations have been applied to sixteen ionic liquids at different temperatures. The objective of the present work is to employ these relations to ionic liquids. The experimental values of ρ and u have been reported in the literature at different temperatures. We have computed thermal expansivity (α), isothermal compressibility (βT), heat capacities ratio (γ), internal pressure (Pint), pseudo-Grüneisen parameter (Г), energy of vaporization (ΔEV), enthalpy of vaporization (ΔHV), cohesive energy density (ced), solubility parameter (δ), refractive index (n), molar refraction (RM) and polarisability (αp) for these liquids. Results are found to quite satisfactory. Keeping in view of uncertainty in the experimental values of ρ and u, as well as some approximations used, the agreement between experimental and theoretical values is found to be quite satisfactory. The results are discussed critically. Introduction: In the present work, we are applying the ρ-u thermodynamic and ρ-u- optical properties correlations to sixteen ionic liquids to estimate thermodynamic and optical properties at different temperature. The experimental values of ρ and u have been reported in the literature at different temperatures. We have computed α, βT, γ, Pint, Г, ΔEV, ΔHV, ced, δ, n, RM and αp for these liquids. Method: Correlations between density-sound velocity and several thermodynamic properties have been derived on the basis of dimensional analysis On the basis of dimensional analysis, a number of useful and important thermodynamic relations were deduced in terms of density (ρ) and speed of sound (u). Result: Results are found to quite satisfactory. Keeping in view of uncertainty in the experimental values of ρ and u, as well as some approximations used, the agreement between experimental and theoretical values is found to be quite satisfactory. Discussion: Density (ρ) and ultrasonic speed (u) data of sixteen RTILs at different temperatures have been taken from the literature. Calculated values of α, βT, Pint, γ, CP-CV, and, Г obtained from empirical relations. The experimental values of α are given for making a comparative study. Conclusion: Based on the dimensional analysis our recently developed correlations between ρ-u- thermodynamic and ρ-uoptical properties have been found to be quite successful when applied to sixteen ionic liquids for the first time. α, βT, γ, Pint, ΔEVap, ΔHVap, ced, δ as well as RM and αp were calculated at various temperatures.

Characteristics and properties of Bitlis ignimbrites and their environmental implications

Bitlis rock is used as a construction material and comes from the lava emitted by volcanoes and their subsequent transformation into ignimbrites. This type of rocks has been characterized physically, chemi­cally, toxicologically and radioactively using different procedures including determination of the coefficient of thermal conductivity, gamma spectrometry, ultrasonic speed test, ICP masses and metal extraction. The results indicate that Bitlis rocks have an ACI greater than 1, although their content of radon is lower than other rocks of volcanic origin. Leaching of metals from these rocks indicates that Pb and Cd can provide an infiltration level in the field higher than the level permitted by TCLP and they have undesired toxicological risks. The percent­ages of extraction of other metals also point to this infiltration problem. Despite this, the material offers good qualities for usage as a building material such as its thermal coefficients.

Intermolecular Interaction of Aqueous Dextran with Urea

In this paper, the authors have given information regarding intermolecular interactions of aqueous dextran solution in urea. The behavior of dextran in urea has been examined by the help of ultrasonic interferometer working at frequency 5MHz at different temperatures ranging from 303 K to 323 K in 5K interval. Ultrasonic speed, density, viscosity measurements have been used for the evaluation of thermodynamic parameters like Gibb’s free energy (ΔG) as well as acoustical parameters are acoustic impedance (Z), isentropic compressibility (β), intermolecular free length (Lf ) and relaxation time (τ), etc. The results have been used to throw light on the nature of the interaction among solute and solvent, interpreted in the light of structural rearrangement occurs in the aqueous dextran and urea solution.

Research on Ion-Solvent Interactions in the Inorganic Liquid Mixtures by Ultrasonic Technique

Ultrasonic speed, density and viscosity of binary liquid mixtures of aqueous ammonium per sulphate with other sulphate solutions at 303.15 K have been measured. From these experimental data, the adiabatic compressibility, intermolecular free length, internal pressure, acoustic impedance, relaxation time, molar volume, classical absorption coefficient and surface tension have been computed. The excess viscosity, excess compressibility, excess intermolecular free length, excess acoustic impedance and excess molar volume values are evaluated to find the nature and the extent of the interactions between the constituent molecules of the liquid mixture systems