Voltage across granular slip failure

Granular materials -- flour, sand, mortar -- exhibit peculiar behavior. Not quite solid and not liquid, you can pile these materials just as easily as you can pour them. When you do pour them, rather than flowing continuously, powder-like materials will tend to fracture, leaving a bulk of material to slip away; think of a mass of earth in a landslide, or snow in an avalanche. Rutgers researchers recently discovered that these types of defects in granular materials produce a voltage, and a high voltage at that, as many as several seconds before the material "breaks" and forms a crack, leaving the bulk of material to disconnect and flow away. Though the time scales are very short, this result could have wide applicability for applications involving granular materials (earth, concrete, for example), leading to advanced structural failure detection in situations where every second counts.