In the sheet metal stamping process. during sliding contact between the tool and sheet. it is expected that severe events such as tool wear or fracture on the sheet generate acoustic emission (AE) burst waveforms. Attempts have been made in the literature to correlate the AE burst waveform with the wear mechanisms. https://www.chiggate.com/l-oreal-preference-permanent-hair-colour-4-tahiti-dark-brown-sale/