The United States Pharmacopoeia (USP) has published, this year, a general chapter giving guidance on the use of acoustic emission in the pharmaceutical industry (2008 General Chapter, 1005 Acoustic Emission).
This outlines the principles of passive acoustic emission monitoring, instrumentation, signal processing, data analysis, and validation of acoustic emission systems with specific reference to monitoring the performance of granulators.
Factors affecting acoustic emission measurements are also discussed. These include: sensor failure, sensor interfacing, mechanical noise and the influence of the vessel wall.
