Black holes, quasars and active galaxies. Black holes are objects so dense, and with so much mass, that even light cannot escape their gravity. The existence of black holes has been theorised for more than 200 years. It is impossible to observe them directly, and astronomers had no way to test their theories until Hubble arrived.
Sequence IIIG Test Method. Sequence IIIG testing for automotive engine oils. The Sequence IIIG Test is a fired-engine, dynamometer lubricant test for evaluating automotive engine oils for certain high-temperature performance characteristics, including oil thickening, varnish deposition, oil consumption, and engine wear.
Biuret test. The biuret test (Piotrowski's test) is a chemical test used for detecting the presence of peptide bonds. In the presence of peptides, a copper(II) ion forms violet-colored coordination complexes in an alkaline solution. Several variants on the test have been developed, such as the BCA test and the Modified Lowry test.