R-410A than other refrigerants. R-410A systems thus require service personnel to use different tools, equipment, safety standards, and techniques. Equipment manufacturers are aware of these changes and require the certification of professionals installing R-410A systems. In addition, the AC&R Safety Coalition has been created to help educate professionals about R-410A systems. In accordance with terms and agreement reached in the Montreal Protocol (The Montreal Protocol on Substances that Deplete the Ozone Layer) the United States Environmental Protection Agency has mandated that production or import of R-22 along with other hydrochlorofluorocarbons (HCFCs) be phased out in the United States. In the EU
Radium, and other radioactive substances Radium, and other radioactive substances Radium, and Other Radio-active Substances; Polonium, Actinium, and Thorium is a book published in 1903 by William Joseph Hammer, when he was about 50 years old. The book is the text of a lecture delivered at a meeting of the American Institute of Electrical Engineers. The title of the lecture was "Radium and other radioactive substances with a consideration of phosphorescent and fluorescent substances. The properties and applications of selenium and the treatment of disease by the ultra violet light". The lecture was augmented by 38 lantern slides, which are reproduced in the book. In