Vapor-compression refrigeration replaced, such as sulfur dioxide. Haloalkanes are also an order(s) of magnitude more expensive than petroleum derived flammable alkanes of similar or better cooling performance. Unfortunately, chlorine- and fluorine-bearing refrigerants reach the upper atmosphere when they escape. In the stratosphere, CFCs break up due to UV radiation, releasing their chlorine free radicals. These chlorine free radicals act as catalysts in the breakdown of ozone through chain reactions. One CFC molecule can cause thousands of ozone molecules to break down. This causes severe damage to the ozone layer that shields the Earth's surface from the Sun's strong UV radiation, and has
The City of the Sun to observe the stars and, using astronomical instruments, to take account of all their movements. It is their job to indicate the times most favorable for generation and for agricultural labors, acting in this way as intermediaries between God and human beings. In Trento's Civic Library, there is kept a 1602 manuscript of "The City of the Sun" (shelf mark BCT1-1538), discovered in 1943 by Italian historian Luigi Firpo. It is considered the most ancient manuscript copy that has survived to present time. The text arrived at the Library through the baron Antonio Mazzetti 's (1781–1841) bequest. He was a