American hardness
a measure of hardness used in the USA. One degree is equal to 1 mg/l

Dictionary of ichthyology. 2009.

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  • hardness — I (New American Roget s College Thesaurus) Solidity Nouns 1. hardness, rigidity, inflexibility, temper, callosity; toughness; petrification, lapidification, lapidescence; vitrification, ossification; crystallization. See density, strength. 2.… …   English dictionary for students

  • hardness — water with a high mineral content, the name deriving from the fact that it is hard to develop a lather for cleaning. The concentration of calcium and magnesium ions in water is expressed as p.p.m. or mg/l of calcium carbonate equivalents. Soft… …   Dictionary of ichthyology

  • Mohs scale of mineral hardness — The Mohs scale of mineral hardness characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer material. It was created in 1812 by the German geologist and mineralogist Friedrich Mohs and… …   Wikipedia

  • degrees of water hardness — dGH (water hardness expressed in degrees of hardness. 0 4 is very soft, 5 8 soft, up to 30 which is extremely hard water). Note that different countries use different measures: 1 English (Clark) degree is 14.3 p.p.m. calcium carbonate, 1 American …   Dictionary of ichthyology

  • water hardness — the concentration of calcium and magnesium ions in water expressed as p.p.m. or mg/l of calcium carbonate equivalents. Water hardness expressed in degrees of hardness. 0 4 is very soft, 5 8 soft, up to 30 which is extremely hard water. Note that… …   Dictionary of ichthyology

  • international rubber hardness degree — (IRHD)    a unit used to measure the hardness of rubber and similar materials (technically known as elastomers). Measurements are made using an IRHD durometer, and the results are usually similar, but not identical, to readings made with the… …   Dictionary of units of measurement

  • knoop hardness — ˈnüp noun Usage: usually capitalized K Etymology: after F. Knoop, 20th century American chemist : the relative hardness of a material (as a metal) that is determined by the depth to which the bluntly pointed diamond pyramid of a special… …   Useful english dictionary

  • rockwell hardness — ˈräˌkwel , kwəl noun Usage: usually capitalized R Etymology: after Stanley P. Rockwell, 20th century American metallurgist : the hardness of a metal or alloy measured by an apparatus in which a diamond pointed cone is pressed into the metal to a… …   Useful english dictionary

  • shore hardness — ˈshō(ə)r , ˈshȯ(ə)r noun Usage: usually capitalized S Etymology: after Albert F. Shore, 20th century American manufacturer : hardness of metal or other material as measured by a Shore scleroscope …   Useful english dictionary

  • James, William — American pragmatism James J.E.Tiles THE BERKELEY LECTURE Pragmatism was introduced to society in a lecture given by William James1 to the Philosophical Union at the University of California in Berkeley on 26 August 1898.2 In his lecture James… …   History of philosophy

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