Using ultrasonic wave reflection to measure solution properties (original) (raw)
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Measurement Of The Nonlinear Ultrasonic Parameter In Aqueous Solutions
This paper deals with the measurement of the nonlinear ultrasound coefficient in aqueous solutions. Our aim is to show the possibility of using this parameter in ultrasound characterization of these solutions with the possibility of extending this technique to other complex media. The experimental determination of nonlinearity parameter is based on the quasi-linear approximation that allows us to derive an analytical expression of the second harmonic amplitude that takes into account the diffraction and the absorption effects. The experimental set up is composed of a piezoelectric disc transmitting at the fundamental frequency 2.2 MHz. The second harmonic is detected using a ring surrounding the disc and functioning at 4.4 MHz. The disc and the ring are both mounted on the same composed device and are both located in the same transversal plan to the propagation axis. The transmitted wave propagates through the sample and is detected by the receiver An appropriate signal processing...
The study of behaviour of propagation of ultrasonic waves in liquid system and solids is now rather well established as an effective means for examining certain physical properties of the materials. It is particularly well adapted to examine changes in such physical properties while they occur. The data obtained from ultrasonic propagation parameters such as ultrasonic velocity, adiabatic compressibility, molar volume, free length etc; and their variation with concentration of one of the component of the medium are useful in understanding the nature of molecular interaction in terms of physical parameters owing to the sensitivity to very low population densities at high energy states ultrasonic methods have been preferred and are reported to be complementary to other techniques like dielectric relaxation, I.R spectroscopy, N.M.R etc. Hence the author preferred to study the ultrasonic velocity and density measurement of aqueous solutions for NaCl and KCl of various concentrations. One of the important intermolecular properties of a liquid is the free length L f between the surfaces of two neighbouring molecules and in the distance covered by the propagating acoustic waves between the surfaces of the two neighbouring molecules. The non-linear variations are observed in acoustic parameters of NaCl and KCl solutions indicating the formation of complex ions. Molecular interactions can be studied through Rao's constants and Wada's constants which are constants in non interacting systems. The abrupt change observed in Rao's constant and Wada's constant shows existence of molecular interaction.
2014
Acoustic investigations make innovations in the study of molecular interactions of solute-solute, solute-solvent, solventsolvent in liquids. The ultrasonic parameters are directly related to a number of thermodynamic parameters. The interactions of urea and molecular dynamics, solute in solvent have been investigated by ultrasonic technique. The ultrasonic velocities and densities have been measured for aqueous solution of Gelatin as a function of concentration, at four different temperatures 298.15K, 303.15K, 308.15K and 313.15K and frequency 2MHz. The experimental data have been used to compute the thermodynamic properties namely adiabatic compressibility (), intermolecular free length () and specific acoustic impedance () for the binary mixtures with a view to investigate the solute-solute and solute-solvent interactions. These thermodynamic parameters have been further used to elicit the ion-ion and solutesolvent in the binary mixtures.
Use of ultrasonic baths for analytical applications: a new approach for optimisation conditions
Journal of the Brazilian Chemical Society, 2001
Com o emprego de um método simples e rápido, são propostas algumas condições de otimização para a obtenção de máxima intensidade de cavitação em banhos de ultra-som. Os parâmetros estudados foram: volume de água dentro do banho, temperatura, concentração de detergente, posição vertical e horizontal dos tubos no banho, número de tubos dentro do banho, tempo de sonicação e substituição da água do banho. Os resultados obtidos para os banhos de ultra-som estudados (Neytech e Cole-Parmer) permitiram estabelecer as seguintes condições para máxima intensidade de cavitação: 1 L de água à temperatura ambiente; 0,2 % (v/v) de detergente; posição central e ao fundo do banho. Somente 1 tubo deve ser usado por vez dentro do banho durante a aplicação do ultra-som. A intensidade de cavitação foi linear com o tempo de sonicação até 10 minutos e a substituição de água durante a sonicação melhorou a reprodutibilidade. Esse sistema de troca contínua de água permite a sonicação de até 6 amostras consecutivamente sem mudanças no volume total de água. Optimisation conditions for obtaining maximum cavitation intensity in ultrasonic baths are proposed using a simple and fast method. Parameters such as water volume, temperature, detergent concentration, horizontal and vertical positions, number of tubes in the bath, sonication time and bath water substitution were studied. The results obtained for both baths studied (Neytech and Cole-Parmer) lead to the following conditions for maximum cavitation intensity: 1 L of water at room temperature, 0.2 % (v/v) of detergent, central position on the bottom of the tank. Only one tube at a time should be used inside the bath during the ultrasound application. The cavitation intensity was linear with the sonication time up to 10 minutes and the water substitution during the sonication improved reproducibility. This system using continuous water change makes possible the sonication of 6 consecutive samples, without changes in the water volume.
Dependence of ultrasonic attenuation on the material properties
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2000
Ultrasonic spectroscopy is a promising measurement technique for the characterisation of emulsions and suspensions over a wide range of particle size and concentration. It appears highly suitable for on-line applications, in particular for dense nano-sized particle systems, where the system stability may be very sensitive to changes in the concentration. In the case of colloidal dispersions the particle sizes are usually smaller than the sound wavelength. Then dissipative processes rather than scattering govern the acoustic behaviour of such systems. The dissipative processes, however, are affected by several material properties, whose significance for the overall acoustic behaviour depends on the type of the material system, e.g. thermal properties are important in the case of emulsions and non-watery suspensions but not for watery suspensions. Often the information on these parameters is incomplete and not sufficiently accurate. In this paper the stability of ultrasonic particle size measurement against incorrect values of the relevant material properties is investigated. This was done firstly by analytical consideration. From this, the degree of influence of the respective material properties on the analysis of spectrometric measurements was derived for oil-water-emulsions, watery and non-watery suspensions. It could be shown that the single properties affect the analysis very differently. In a second step, the conclusions obtained analytically could be confirmed by analysing experimental attenuation spectra with slightly changed material property data. The paper is intended to give users of ultrasonic spectroscopy a practical guide for deciding which material properties have to be obtained with high accuracy and which can be estimated. : S 0 9 2 7 -7 7 5 7 ( 0 0 ) 0 0 5 7 1 -9
Absorption and velocity of acoustical waves in binary solutions of poly (ethylene glycol) and water
Journal of The Acoustical Society of America, 2008
The velocity and absorption of ultrasonic waves have been measured in aqueous solutions of poly (ethylene glycol). The velocity of ultrasonic waves was obtained in the frequency range 1MHz-12MHz over a wide range of temperature. The concentration (by weight) ranged from 1% to 10% of poly (ethylene glycol) in water. The shear viscosity was also measured. Measurements were carried out in the temperatures range 35 o C to 65 o C. It was observed that velocity of ultrasonic wave increases with temperature at a given concentration, while as concentration is increased at a given temperature, velocity was found to increase. The shear viscosity and density decreased with temperature
Acoustic spectroscopy: A powerful analytical method for the pharmaceutical field?
International Journal of Pharmaceutics, 2016
Acoustics is one of the emerging technologies developed to minimize processing, maximize quality and ensure the safety of pharmaceutical, food and chemical products. The operating principle of acoustic spectroscopy is the measurement of the ultrasound pulse intensity and phase after its propagation through a sample. The main goal of this technique is to characterise concentrated colloidal dispersions without dilution, in such a way as to be able to analyse non-transparent and even highly structured systems. This review presents the state of the art of ultrasound-based techniques in pharmaceutical preformulation and formulation steps, showing their potential, applicability and limits. It reports in a simplified version the theory behind acoustic spectroscopy, describes the most common equipment on the market, and finally overviews different studies performed on systems and materials used in the pharmaceutical or related fields.
Journal of Research in Engineering and Applied Sciences, 2017
The basic parameters like velocity (U), density(ρ) and viscosity (η) can be measured by ultrasonic Interferometer. From these parameters various thermodynamical and acoustical parameters such as adiabatic compressibility 's (β), specific acoustic impedance (Z), Solvation number (S), Intermolecular free length (L), have been estimated using standard relations from n f 0 0 measured values of Ultrasonic velocities, densities and viscosities in the wide range of concentrations at 35 C, 40 C and 0 45 C temperatures for Acetone + Propanol-2 +Toluene tertiary system. The solvent-solvent interactions are studied on the basis of increase or decrease in ultrasonic velocity, density, viscosity and other derived acoustical parameters in terms of structure making and structure breaking tendencies of various solvent molecules.