| Particle size is an important quality property which has major influence on the stability, solubility and flowbility of the finial product. In recent years, measurement of particle size distribution(PSD) in the suspensions and emulsions using ultrasound attenuation spectroscopy(UAS) method has received much attention in the pharmaceutical, petrochemical and food industries. UAS has demonstrated advantages of strong penetrability, wide frequency range, fast response speed and non-invasive, therefore it is suitable for measurement of high concentration slurry particle system of nanometer and micron range.Despite of that, it still needs further research to address some challenges facing the use of UAS. This paper firstly introduced the theoretical model and development of the principle of UAS. Based on a newly developed UAS probe in our group, this study focuses a few challenging issues facing the real industrial use of the UAS probe. Firstly, the reliability and stability of the device was investigated. This was conducted by reference to a nanometer titanium dioxide-water suspension and a micro silica-water suspension in different concentrations. Then the UAS spectrometer was used together with other PAT techniques in monitoring Aspirin crystallization.In addition, as a result of the difficulties in the measurement of physical parameters of continuous phase and dispersed phase used in models, this paper proposed a method for estimation of parameters with optimization algorithms. The results show that the deviation between the fitted values and the real value in the known system is very close. Meanwhile, the PSD obtained with the optimization results is almost the same with its real distribution. This method is an efficient tool to implement ultrasound attenuation into particle size measurement in complex systems. |
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