Figure 1.

(a) At each boundary between two materials, part of the ultrasound wave is reflected. The proportion of the sound wave energy reflected is dependent on the acoustic impedance mismatch between the materials. The ultrasound wave of interest in this study is that reflecting back from the vessel–mixture interface to the transducer. (b) Diagram showing the position of the two ultrasound sensors on the vessel base to monitor honey-water blending. (c) Diagram showing the position of the two ultrasound sensors on the side of the mixing bowl to monitor the flour-water batter mixing.