“…Referred to [17], if only one ultrasonic pulse is allowed to travel in an ultrasonic cell, the expression for the attenuated pulse, neglecting echoes, can be readily written as A is the wave amplitude after it has traveled the distance x , 0 A is the initial amplitude, α is the total attenuation coefficient which may possibly comprise viscous, thermal, scattering and relaxation losses, excluding the classical absorption due to low frequency limit [18]. The scattering effects can be negligible, if the wavelength of the ultrasonic wave is much greater than molecular sizes, [19][20].…”