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.
Hysterosalpingography (HSG) is a radiologic procedure to investigate the shape of the uterine cavity and the shape and patency of the fallopian tubes. It entails the injection of a radio-opaque material into the cervical canal and usually fluoroscopy with image intensification.he procedure involves X-rays. It should be done in the follicular phase of the cycle. It is contraindicated in pregnancy. It is useful to diagnose uterine malformations, Asherman's syndrome, tubal occlusion and pelvic inflammatory disease and used extensively in the work-up of infertile women.