Asphalt driveways are typically less expensive than concrete, costing a minimum of about $2.50 per square foot. An asphalt driveway might last just 20 years; however, while a concrete driveway can last more than 30.
Semipermeable membrane. The diffusion of water through a selectively permeable membrane is called osmosis.This allows only certain particles to go through including water and leaving behind the solutes including salt and other contaminants. In the process of reverse osmosis, thin film composite membranes (TFC or TFM) are used.
selectively permeable (or differentially permeable), allowing some substances to pass through easily, while completely or partially excluding others. Although there are several methods by which solutes may enter or leave cells, the most common is diffusion. Diffusion is the movement of a substance (e.g. molecules and ions) from a region of higher