Bark (botany) rope, used for example in the rigging of Viking age longships. Among the commercial products made from bark are cork, cinnamon, quinine (from the bark of Cinchona) and aspirin (from the bark of willow trees). The bark of some trees notably oak ("Quercus robur") is a source of tannic acid, which is used in tanning. Bark chips generated as a by-product of lumber production are often used in bark mulch in western North America. Bark is important to the horticultural industry since in shredded form it is used for plants that do not thrive in ordinary soil, such as epiphytes.
Naturally aspirated engine Naturally aspirated engine A naturally aspirated engine is an internal combustion engine in which oxygen intake depends solely on atmospheric pressure and does not rely on forced induction through a turbocharger or a supercharger. Many sports cars specifically use naturally aspirated engines to avoid turbo lag. In a naturally aspirated engine, air for combustion (diesel cycle in a diesel engine or specific types of Otto cycle in petrol engines—namely petrol direct injection), or an air/fuel mixture (traditional Otto cycle petrol engines)—is drawn into the engine’s cylinders by atmospheric pressure acting against a partial vacuum that occurs as the piston travels