one of the natural hazards in mountainous areas, which always cause great losses of life and financial damages, is the avalanche fall. since, survey the avalanche-prone areas for prevention the probable damages is considerably important, especially when the avalanche paths affect the residential areas or roads. in this research, based on local information, one of the avalanche paths in the chah...

Inelastic deformation of metallic glasses occurs via slip events with avalanche dynamics similar to those of earthquakes. For the first time in these materials, measurements have been obtained with sufficiently high temporal resolution to extract both the exponents and the scaling functions that describe the nature, statistics and dynamics of the slips according to a simple mean-field model. Th...

We study the avalanche dynamics of a system of globally coupled threshold elements receiving random input. The model belongs to the same universality class as the random-neighbor version of the Olami-Feder-Christensen stick-slip model. A closed expression for avalanche size distributions is derived for arbitrary system sizes N using geometrical arguments in the system's configuration space. For...

We report the sudden appearance of upconversion fluorescence and resonant increasing absorption above a threshold intensity in Tm:YALO 3 at room temperature. These effects are shown to arise from nonlinear, cooperative , excited-state dynamics. Comparison with quantum theory reveals essential roles both for pairwise cross relaxation and excitation migration among Tm impurity ions. Absorption fe...

The avalanche behavior of gravitationally forced granular layers on a rough inclined plane is investigated experimentally for different materials and for a variety of grain shapes ranging from spherical beads to highly anisotropic particles with dendritic shape. We measure the front velocity, area, and height of many avalanches and correlate the motion with the area and height. We also measure ...