As far as the tile roofs, they last a long time. It isn't the tile that is the issue, it's the felt (or paper) underneath that gets replaced. Mine is 25 years old, has not been replaced yet. Some neighbors have had theirs redone, but many have not as yet. 04-06-2011, 12:00 AM.
Particle Accelerators Could Be Used to Produce Energy (and Plutonium) Particle accelerators, which are not renowned for their real-world applications, could in fact be used to produce energy, according to a 34-year-old research paper that resurfaced this week.
The Van de Graaff generator was developed as a particle accelerator in physics research, its high potential is used to accelerate subatomic particles to high speeds in an evacuated tube. It was the most powerful type of accelerator in the 1930s until the cyclotron was developed.