Real-time

on-line measurement of moisture content of particles has become one of the most important issues in drying process controlling.In this work

acoustic emission (AE) technique was applied to determine the moisture content.A characteristic frequency band of AE signals

which represents the moisture content

was obtained by using wavelet transform and spectral analysis.The analysis results showed that

with the decrease of moisture content

the 1st and 3rd energy fractions decreased and increased respectively

and the characteristic peak moved to lower frequency.Furthermore

a moisture prediction model based on the characteristic frequency analysis was constructed

which could quantitatively establish the relationship between the energy features and moisture.The root mean square error (RMSE) of the prediction model was 0.0422

indicating that the model predicted the moisture with high precision.The AE method is a non-intrusive and rapid technique that makes online measurement possible

which has a positive impact on process optimization and product upgrading.