How many weeks' holiday a year are there?
cheap valium online pharmacy According to the theoretical limit, the minimum time a bouncing droplet can stay in contact with a surface???first spreading out into a pancake-like shape, then pulling back inward due to surface tension and bouncing away???depends on the time period of oscillations in a vibrating drop, also known as the Rayleigh time. The way to achieve that minimum contact time, the conventional wisdom holds, is to minimize interaction between the water and the surface, such as by creating low-adhesion superhydrophobic surfaces.