Janka hardness test Janka hardness test The Janka hardness test (from the Austrian-born emigrant Gabriel Janka, 1864-1932) measures the resistance of a sample of wood to denting and wear. It measures the force required to embed an diameter steel ball halfway into a sample of wood. A common use of Janka hardness ratings is to determine whether a species is suitable for use as flooring. The hardness of wood varies with the direction of the wood grain. Testing on the surface of a plank, perpendicular to the grain, is said to be of "side hardness". Testing the cut surface of a stump is
Bial's test published a procedure for simultaneous determination of pentoses and hexoses from measurements at two wavelengths. Various versions of this test are widely used for a quick chemical determination of RNA; in this context it is usually called the orcinol test. Bial's test Bial's test is a chemical test for the presence of pentoses. It is named after Manfred Bial, a German physician. The components include orcinol, hydrochloric acid, and ferric chloride. A pentose, if present, will be dehydrated to form furfural which then reacts with the orcinol to generate a colored substance. The solution will turn bluish and a precipitate