Zinc, in commerce also spelter, is a chemical element; it has the symbol Zn and atomic number 30. It is the first element of group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is 2. Zinc is the 24th most abundant element in the Earth's crust and has five stable . The most common zinc ore is sphalerite (zinc blende), a zinc sulfide mineral. The largest mineable amounts are found in Australia, A..
Copper is a chemical element with the symbol Cu (from cuprum) and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; a freshly exposed surface has a reddish-orange color. It is used as a conductor of heat and electricity, a building material, and a constituent of various metal .
A social network is a social structure made up of a set of social actors (such as individuals or organizations), sets of dyadic ties, and other Social relation between actors. The social network perspective provides a set of methods for analyzing the structure of whole social entities as well as a variety of theories explaining the patterns observed in these structures. ξ1 The study of these structures uses social network analysis to identify local and global patterns, locate influential entities, and ..
Asbestos (pronounced , or ) is a set of six naturally occurring silicate minerals, which all have in common their eponymousasbestiformhabit: long (roughly 1:20 aspect ratio), thin fibrous, with each visible fiber composed of millions of microscopic "fibrils" that can be released by abrasion and other processes. They are commonly known by their colors, as blue asbestos, brown asbestos, white asbestos, and green asbestos.
