Fusion is the sun’s energy source. It is essentially inexhaustible, and that’s a major reason for the interest in developing fusion technology to generate power. In the sun, light nuclei such as hydrogen, under extreme gravitational pressure and excited by temperatures of 10 million to 20 million°C, collide with such force that they are fused into heavier ones. The fusion generates heat, maintaining the high temperature and keeping the reaction going. Slide Show Photo: Agence Iter France Related Links: International Program Aims To Develop Energy Supply Without Limit Fusion in earth’s lower pressure requires a much higher temperature of 100
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.