Hardness
61Mohs 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… …
62Barcol hardness test — The Barcol hardness test characterizes the indentation hardness of materials through the depth of penetration of an indentor, loaded on a material sample and compared to the penetration in a reference material. The method is most often used for… …
63Meyer hardness test — This graph shows the differences between the Brinell hardness test and the Meyer hardness test. Notice that the Brinell test can report the same hardness value for a given specimen twice depending on the load. The Meyer hardness test is a rarely… …
64Mohs hardness — Rough measure of the resistance of a smooth surface to scratching or abrasion, expressed in terms of a scale devised by German mineralogist Friedrich Mohs in 1812. Minerals are ranked in comparison with the Mohs scale, which is made up of 10… …
65Mohs hardness scale and observations on hardness of some additional materials — ▪ Table Mohs hardness scale and observations on hardness of some additional materials mineral Mohs hardness other materials observations on the minerals talc 1 very easily scratched by the fingernail; has a greasy feel gypsum 2 Mohs hardness… …
66Carbonate hardness — is the measure of Calcium and Magnesium and other hard ions associated with carbonate (CO32 ) and bicarbonate (HCO3 ) ions contained in a solution, usually water. It is usually expressed either as parts per million (ppm or mg/L), or in degrees… …
67Janka hardness test — hi The Janka hardness test measures the hardness of wood. It involves measuring the force required to embed a 11.28 millimeter (0.444 inch) steel ball into wood to half its diameter. This method was chosen so that the result would leave an… …
68Computational hardness assumption — In cryptography, a major goal is to create cryptographic primitives with provable security. In some cases cryptographic protocols are found to have information theoretic security, the one time pad is a common example. In many cases, information… …
69pencil hardness — a traditional measure of the hardness of the leads (actually made of graphite) in pencils. The hardness scale, from softer to harder, takes the form ..., 3B, 2B, B, HB, F, H, 2H, 3H, 4H, .... The letters stand for Black, Hard, and Firm. (There …
70Knoop hardness test — The Knoop hardness test is a microhardness test a test for mechanical hardness used particularly for very brittle materials or thin sheets, where only a small indentation may be made for testing purposes. A pyramidal diamond point is pressed into …
