Directed percolation, a class of nonequilibrium phase transitions as prominent as the Ising model in equilibrium statistical mechanics, is realized experimentally for the first time, after more than fifty years of research.
Scaling laws are a useful way to characterize fluid flow over a wide range of flow rates and experimental conditions. Theorists now explain several earlier experiments by finding a scaling law that describes how a liquid-liquid interface changes shape when driven by viscous forces.
High-intensity x-ray measurements show how suspended particles in a narrow channel are attracted to—or repelled from—the channel walls depending on the ionic concentration of the suspension. These results could have implications for the design of nanofluidic devices.
A shear force can melt a colloidal glass, causing it to flow in a highly nonlinear fashion. Physicists have now found a way to put the description of this type of flow on a more formal theoretical footing.
Phys. Rev. Focus21, 2 (2008) – Published January 15, 2008
A pair of colliding water droplets merges on the rebound, rather than when they’re squeezing against each other. The results should improve understanding of the separation process of oil-water mixtures important in industry.