Journal of Pure and Applied Ultrasonics

Kailash ¹, K. M. Raju ¹, P. Yadav ¹

Affiliations
1 Department of Physics, Brahmanand Post-Graduate College, Rath, Hamirpur, UP, IN

Abstract

Milk is considered as an important food ingredient for a major sector of-population. Extensive study about milk quality has been reported in the recent past. Very little work has been done to study the quality of milk using ultrasonic techniques. This has motivated us to undertake the present study. In this paper, we have made detailed investigations of ultrasonic wave velocities in milk at different concentrations using single frequency ultrasonic interferometer.

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Kailash ¹, K. M. Raju ¹, Khare ¹

Affiliations
1 Department of Physics, Brahmanand Post-Graduate College, Rath, Hamirpur-210431, U.P., IN

Abstract

If the values of second order elastic constants and density at a particular temperature are known for any substance, one may obtain ultrasonic velocities for longitudinal and shear waves which give an important information about its anharmonic properties. For computing the second and third order elastic constants (SOECs & TOECs) at any temperature, a method have been developed, starting from nearest neighbour distance and hardness parameter assuming Coulomb and Born Mayer potentials for face centered cubic crystals. The anharmonic properties of lithium halides are evaluated at different temperatures (100 K to upto their melting points) using this formulation. The results obtained in present investigation are in reasonable agreement with other studies.

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Kailash ¹, K. M. Raju ¹, S. K. Shrivastava ², S. Kushwaha ³

Affiliations
1 Department of Physics, Brahmanand Post-Graduate College, Rath, Hamirpur-210431, UP, IN
2 Institute of Basic Sciences, Bundelkhand University, Jhansi-284128, UP, IN
3 Department of Physics, Pt. J.N. P.G. College, Banda-210001, UP, IN

Abstract

An effort has been made for obtaining the second order elastic constants of rocksalt structure solids starting from primary physical parameters viz. nearest neighbour and hardness parameter assuming long- and short-range potentials at an elevated temperature. When the values of the second order elastic constants are known for a crystal, many of the anharmonic properties of the crystal can be treated within the limit of the continuum approximation in quantitative manner. The ultrasonic velocity any crystal is directly related to their second order elastic constants (v-longitudianal=(C₁₁/d)^1/2, v-shear=(C₄₄/d)^1/2;d is density). In this study, second order elastic constants are computed upto their melting temperature for rocksalt structure solids, which are alkali cyanides, sodium and potassium halides. The results thus obtained are compared with experimental data and found in well agreement with present values.

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