fixed nitrogen
71metabolism — /meuh tab euh liz euhm/, n. 1. Biol., Physiol. the sum of the physical and chemical processes in an organism by which its material substance is produced, maintained, and destroyed, and by which energy is made available. Cf. anabolism, catabolism …
72coal utilization — Introduction combustion of coal or its conversion into useful solid, gaseous, and liquid products. By far the most important use of coal is in combustion, mainly to provide heat to the boilers of electric power plants. Metallurgical coke… …
73Scuba diving — Not to be confused with Self contained breathing apparatus, which describes breathing sets used out of water. Scuba diver Scuba diving ( SCUBA originally being an acronym for self contained underwater breathing apparatus, now widely considered a… …
74atom — /at euhm/, n. 1. Physics. a. the smallest component of an element having the chemical properties of the element, consisting of a nucleus containing combinations of neutrons and protons and one or more electrons bound to the nucleus by electrical… …
75photography, technology of — Introduction equipment, techniques, and processes used in the production of photographs. The most widely used photographic process is the black and white negative–positive system (Figure 1 >). In the camera the lens projects an image of… …
76Atomic theory — Atomic model redirects here. For the unrelated term in mathematical logic, see Atomic model (mathematical logic). This article is about the historical models of the atom. For a history of the study of how atoms combine to form molecules, see… …
77chemical compound — Introduction any substance composed of identical molecules consisting of atoms (atom) of two or more chemical elements (chemical element). All the matter in the universe is composed of the atoms of more than 100 different chemical elements …
78Carbon dioxide — Carbon dioxide …
79Saturn V Instrument Unit — The Saturn V Instrument Unit is a ring shaped structure fitted to the top of the Saturn V rocket s third stage (S IVB) and the Saturn IB s second stage (S IVB). It was immediately below the SLA (Spacecraft/Lunar Module Adapter) panels that… …
80Gas — This article is about the physical properties of gas as a state of matter. For the uses of gases, and other meanings, see Gas (disambiguation). Ga …
