Gray (unit) Gray (unit) The gray (symbol: Gy) is a derived unit of ionizing radiation dose in the International System of Units (SI). It is defined as the absorption of one joule of radiation energy per kilogram of matter. It is used as a unit of the radiation quantity absorbed dose which measures the energy deposited in a unit mass at a certain position, and of the radiation quantity kerma, which is the amount of energy that is transferred from photons to electrons per unit mass at a certain position. The corresponding cgs unit to the gray is the rad (equivalent to
The Quest: Energy, Security, and the Remaking of the Modern World The Quest: Energy, Security, and the Remaking of the Modern World The Quest: Energy, Security, and the Remaking of the Modern World is an international bestselling book by energy expert Daniel Yergin. The book was initially published on September 20, 2011 through Penguin Press and is considered to be the follow-up to Yergin’s 1992 Pulitzer Prize winning history of oil, "", and describes the development of the current energy system and prospects for the future. Upon its release, the book received praise and criticism both for its breadth of subject as well as for its impartiality. It is often suggested