heat-producing element

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• Heat exchanger — An interchangeable plate heat exchanger Tubular heat exchan …   Wikipedia

• rare-earth element — /rair errth /, Chem. any of a group of closely related metallic elements, comprising the lanthanides, scandium, and yttrium, that are chemically similar by virtue of having the same number of valence electrons. Also called rare earth metal. [1955 …   Universalium

• chemical element — Introduction also called  element,         any substance that cannot be decomposed into simpler substances by ordinary chemical processes. Elements are the fundamental materials of which all matter is composed.       This article considers the… …   Universalium

• actinide element — ▪ chemical element group Introduction       any of a series of 15 consecutive chemical elements in the periodic table from actinium to lawrencium (atomic numbers 89–103). As a group they are significant largely because of their radioactivity.… …   Universalium

• transition element — Chem. any element in any of the series of elements with atomic numbers 21 29, 39 47, 57 79, and 89 107, that in a given inner orbital has less than a full quota of electrons. Also called transition metal. [1920 25] * * * Any chemical element with …   Universalium

• Transposable element — A bacterial DNA transposon Transposable elements (TEs) are sequences of DNA that can move or transpose themselves to new positions within the genome of a single cell. The mechanism of transposition can be either copy and paste or cut and paste .… …   Wikipedia

• nitrogen group element — ▪ chemical elements Introduction  any of the chemical elements that constitute Group Va of the periodic table (see Figure >). The group consists of nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), and bismuth (Bi). The elements share… …   Universalium

• oxygen group element — ▪ chemical element Introduction also called  chalcogen,    any of the five chemical elements making up Group 16 (VIa) of the periodic classification namely, oxygen, sulfur, selenium, tellurium, and polonium. (See Figure >.) A relationship among… …   Universalium

• KREEP — KREEP, an acronym built from the letters K (the atomic symbol for the element potassium), REE (Rare Earth Elements) and P (for phosphorus), is a geochemical component of some lunar impact melt breccia and basalt rocks. Its most significant… …   Wikipedia

• technology, history of — Introduction       the development over time of systematic techniques for making and doing things. The term technology, a combination of the Greek technē, “art, craft,” with logos, “word, speech,” meant in Greece a discourse on the arts, both… …   Universalium

• earth — /errth/, n. 1. (often cap.) the planet third in order from the sun, having an equatorial diameter of 7926 mi. (12,755 km) and a polar diameter of 7900 mi. (12,714 km), a mean distance from the sun of 92.9 million mi. (149.6 million km), and a… …   Universalium