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plastic

(Encyclopedia)plastic, any organic material with the ability to flow into a desired shape when heat and pressure are applied to it and to retain the shape when they are withdrawn. The first important plastic, cel...

radiosonde

(Encyclopedia)radiosonde rāˈdēōsŏnd [key], group of instruments for simultaneous measurement and radio transmission of meteorological data, including temperature, pressure, and humidity of the atmosphere. The ...

spinal puncture

(Encyclopedia)spinal puncture, surgical penetration of the spinal canal by a hollow needle introduced between two of the lumbar vertebrae. The arrangement permits injection of antibiotics or anesthetics (see anesth...

stellar structure

(Encyclopedia)stellar structure, physical properties of a star and the processes taking place within it. Except for that of the sun, astronomers must draw their conclusions regarding stellar structure on the basis ...

hypertension

(Encyclopedia)hypertension or high blood pressure, elevated blood pressure resulting from an increase in the amount of blood pumped by the heart or from increased resistance to the flow of blood through the small a...

fuel injection

(Encyclopedia)fuel injection, system in an internal-combustion engine that delivers fuel or a fuel-air mixture to the cylinders by means of pressure from a pump. It was originally used in diesel engines because of ...

nosebleed

(Encyclopedia)nosebleed, nasal hemorrhage occurring as the result of local injury or disturbance. Most nosebleeds are not serious and occur when one of the small veins of the septum (the partition between the nostr...

Bergius, Friedrich Karl Rudolf

(Encyclopedia)Bergius, Friedrich Karl Rudolf, 1884–1949, German chemist, Ph.D. Univ. of Leipzig, 1907. In 1910, Bergius set up a laboratory to carry out his research and in 1914 transferred the operation to the E...

kinetic-molecular theory of gases

(Encyclopedia)kinetic-molecular theory of gases, physical theory that explains the behavior of gases on the basis of the following assumptions: (1) Any gas is composed of a very large number of very tiny particles ...

Henry's law

(Encyclopedia)Henry's law, chemical law stating that the amount of a gas that dissolves in a liquid is proportional to the partial pressure of the gas over the liquid, provided no chemical reaction takes place betw...