A foam is a space-filling cellular pattern, that can be decomposed into successive layers or strata. Each layer contains all cells at the same topological distance to an origin (cell, cluster of cells, or basal layer). The disorder of the underlying structure imposes a characteristic roughening...

Clear skies are important in predicting the peak solar irradiance and daylight illuminance levels for active solar energy utilisation and passive energy-efficient building designs. The clearness of a sky is affected by the clarity of the atmosphere which is usually expressed in terms of a...

We review some selected experimental and theoretical studies which relate to nonlinear phenomena in soap froth. These include the rigidity loss transition of a foam and the occurrence of a solitary wave in foam drainage.