  Acoustic emission or crackling noise is measured from an experiment on
splitting or peeling of paper. The energy of the events follows a power-law,
with an exponent $\beta \sim 1.8\pm 0.2$. The event intervals have a wide
range, but superposed on scale-free statistics there is a time-scale, related
to the typical spatial scale of the microstructure (a bond between two fibers).
Since the peeling takes place via steady-state crack propagation, correlations
can be studied with ease and shown to exist in the series of acoustic events.

Disordered Systems and Neural Networks;Statistical Mechanics