In this paper, an ultrasonic transducer (UT) is integrated onto the bottom of a specially designedfrozen bottle for the purpose of monitoring the freeze-drying process of water under various freezingrate. The temperature and visual observation made with a camera are then compared with thecorresponding ultrasonic signature. In order to evaluate the various freezing rate, two kinds of freezedryingprocesses are designed. The temperature and ultrasonic signals indicated the phase changeof cooling and freezing periods. These two periods are shorter when the shelf temperature is set ata lower value. However, only ultrasonic signals indicate the phase change of drying period. Thevisual observation indicates that the lower shelf temperature setting results in the smaller ice crystalnuclei. This study demonstrates an innovative frozen bottle with an integrated ultrasonic sensor usedto measure the freeze-drying process of water under the various freezing rates.
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