Der Gehalt an gelösten Calcium- u. Magnesiumverbindungen. Nach den Deutschen Härtegraden gilt: 0 4 d sehr weich; 4 8 d weich; 8 18 d mittelhart; 18 30 d hart; < 30 d sehr hart. Hartes Wasser ist unerwünscht, weil Seifen mit den Calciumverbindungen unlösl. Salze bilden u. weil sich in Dampfkesseln Kesselstein absetzt.
ETYM AS. heardness.
The measure of a materials resistance to deformation by surface indentation or by abrasion.
1. The property of being rigid and resistant to pressure; not easily scratched.
2. The quality of being difficult to do.
Physical property of materials that governs their use. Methods of heat treatment can increase the hardness of metals. A scale of hardness was devised by German–Austrian mineralogist Friedrich Mohs in the 1800s, based upon the hardness of certain minerals from soft talc (Mohs' hardness 1) to diamond (10), the hardest of all materials.
See also Brinell hardness test. The hardness of water refers to the presence of dissolved minerals in it that prevent soap lathering, particularly compounds of calcium and magnesium. Treatment with a water softener may remove or neutralize them.
1. Harsh or rough to the ear; SYN. roughness.
2. The roughness of a substance that causes abrasions; SYN. abrasiveness, scratchiness.
Mercilessness characterized by an unwillingness to relent or let up; SYN. inexorability, inexorableness.
(Alternate spelling: rigour)
(Homonym: rigger)
1. Rigidity; stiffness.
2. A sense of chilliness, with contraction of the skin; a convulsive shuddering or tremor, as in the chill preceeding a fever.
Shiver; chill; rigidity; abbreviation of rigor mortis.
Medical term for shivering or rigidity. Rigor mortis is the stiffness that ensues in a corpse soon after death, owing to chemical changes in muscle tissue.
Alternate (chiefly British) spelling for rigor.
ETYM Latin severitas: cf. French sévérité.
Excessive sternness; SYN. harshness, inclemency, hardness, stiffness.
Quality of being stony, quality of being hard and cold; lack of pity and compassion
A measure of the energy absorbed before and during the fracture process; it is equal to the area under the tensile stress-strain curve.