Work (thermodynamics) of the energy went out as heat, and how much as work. This can be summarized by saying that heat and work are not state functions of the system. This is in contrast to classical mechanics, where net work exerted by a particle is a state function. Pressure–volume work (or "PV" work) occurs when the volume of a system changes. "PV" work is often measured in units of litre-atmospheres where = . However, the litre-atmosphere is not a recognised unit in the SI system of units, which measures P in Pascal (Pa), V in m, and PV in Joule (J),
Energy-Safety and Energy-Economy "Energy Safety and Energy Economy" publishes a quarterly appendix. "Energy Safety and Energy Economy" is a winner of the National Ecological Prize, Russian Energy Olympus contest, Social and Economic Significant Projects in Education, Culture and Ecology contest, Save Energy contest, and others. Energy-Safety and Energy-Economy Energy Safety and Energy Economy () is a peer-reviewed scientific and technical journal covering energy safety and economy, safety regulations, personnel training, innovation, and recent trends in alternative power sources research. The editor-in-chief is Svetlana Zernes (). It was established in 2005 as "Energy Safety in Documents and Facts Journal", obtaining its current title in