The Measurement Of Basic Acoustic Parameters In Materials And Its Applications In Food Safety

The basic acoustic parameters of material include the velocity, attenuation coefficient and acoustic nonlinear parameter B/A, etc. They all play important roles in the non-destructive test, ultrasonic tissue-mimicking materials properties testing and medical imaging. In this paper the three parameters and their applications in food safety had been studied, the main work is as follows:1. Compare the measuring methods of velocity and attenuation coefficient. Use the insert substitution method to measure the two parameters, do the diffraction correction and the analysis of the uncertainty.2. Use the finite amplitude insert substitution method to measure the acoustic nonlinear parameter B/A, and do the correction and the uncertainty analysis. Studied the influencing effects of temperature, sound intensity and frequency on the acoustic nonlinear parameter B/A. The results show that the B/A value increases linearly with the temperature increase, the sound intensity has little effect on B/A, and B/A value decreases linearly with the increase of frequency.3. Applying the velocity and the attenuation coefficient to the detection of melamine in milk, the results show:As the melamine concentration in milk increases, the speed of sound shows a linearly downward trend, and the attenuation coefficient shows only a little slight downward trend. Using the acoustic nonlinear parameter B/A to monitor the deterioration process of milk, the result shows:With the growth of storage time, the B/A values are significantly changed.