Differential Method of Measuring Ultrasonic Absorption in Liquids

Abstract

We give a new method of measuring the difference of ultrasonic absorption of two liquids. Two pulse generators excite two ultrasonic quartz transducers in two vessels. Having passed through the two vessels, the pulses are reflected from the opposite walls of the vessels and are received by the same quartz transducers. The received signals are amplified, detected, and then amplified again by a differential dc amplifier at the output of which there is a milliammeter. The milliammeter readings are proportional to the difference of two liquids absorption coefficients. The sensibility of the apparatus is evaluated by the value xΔα giving a current 1 ma (x—the double width of the vessel, Δα—the difference between absorption coefficients). For example, at x = 9 cm the sensibility equals Δα = 0.01 cm−1 per 1 ma. The accuracy of Δα measurement is nearly 3–5%. By means of the apparatus described in the foregoing, one can measure the absorption of ultrasonic diluted solutions, the temperature absorption coefficients of ultrasonic waves in liquids, coefficients of reflections from solid-liquid, liquid-liquid boundaries, and other applications.