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.
Think of food coloring that spreads out in a glass of water, or air freshener sprayed in a room. Selectively Permeable - membranes that allow some things through, the cell membrane is selectively permeable, water and oxygen move freely across the cell's membrane, by diffusion Words You Should Know: