constructional material
41Vault (architecture) — A Vault (French. voute, Italian. volta, German. Gewölbe, Polish. sklepienie , Spanish. bóveda ) is an architectural term for an arched form used to provide a space with a ceiling or roof. url=http://concise.britannica.com/ebc/article… …
42Y and Z Holes — The Y and Z Holes are two rings of concentric (though irregular) circuits of near identical pits cut around the outside of the Sarsen Circle at Stonehenge. The current view is that both circuits are contemporary. Radiocarbon dating of antlers… …
43rope — roper, n. ropelike, adj. /rohp/, n., v., roped, roping. n. 1. a strong, thick line or cord, commonly one composed of twisted or braided strands of hemp, flax, or the like, or of wire or other material. 2. a lasso. 3. ropes, a. the cords used to… …
44human embryology — ▪ biology Introduction the process encompassing the period from the formation of an embryo, through the development of a fetus, to birth. The human body, like that of most animals, develops from a single cell produced by the union of… …
45molybdenum processing — Introduction preparation of the ore for use in various products. Molybdenum (Mo) is a white, platinum like metal with a melting point of 2,610° C (4,730° F). In its pure state, it is tough and ductile and is characterized by moderate… …
46Noachian — MOLA colorized relief map of Noachis Terra, the type area for the Noachian System. Note the superficial resemblance to the lunar highlands. Colors indicate elevation, with red highest and blue violet lowest. The blue feature at bottom right is… …
47Water wheel — This article is about the machine for converting energy of flowing or falling water. For paddle wheels used to propel watercraft, see paddle wheel ship. For wheels used solely to lift water, see Noria. For factories or industries driven by water… …
48Choline — The N,N,N trimethylethanolammonium cation, with an undefined counteranion, X− Choline is a water soluble essential nutrient.[1][ …
49Pacific Ring of Fire — The Ring of Fire redirects here. For other uses of the term, see Ring of Fire (disambiguation). The Pacific Ring of Fire (see below) …
50Project Habakkuk — or Habbakuk (spelling varies; see below) was a plan by the British in World War II to construct an aircraft carrier out of pykrete (a mixture of wood pulp and ice), for use against German U boats in the mid Atlantic, which were beyond the flight… …
