Fig xA Examples of different detected AE

During each of the performed experiments (Table 1) an extended set of AE signals was acquired. In order to further analyze and characterize SCC process by means of AE, it Refametinib was necessary to select AE bursts which had presumably been caused by events related to SCC. On the basis of the above observed characteristics of AE signals in time and frequency space, two different procedures of noise signals filtering were proposed, with the aim of selecting the SCC process related AE signals from the complete set of acquired AE signals. The filtering procedures are presented schematically in the block diagram shown in Fig. 4. The left branch of the block diagram presents manual filtering of the AE signals, based on the visually observed AE waveform characteristics, whereas in the right branch of the block diagram an automatic, a method for AE signal amplitude and average frequency based filtering is presented. In the visual inspection based procedure the signals detected during the performed change of specimen loading are first eliminated. Further in the procedure all signals bark do not poses the previously described characteristic waveform of an exponentially decaying burst are eliminated.