A mercury arc valve (mercury vapor rectifier) is a type of electrical rectifier which converts alternating current into direct current. Rectifiers of this type were used in electric motor power supplies for industry, in electric railways, streetcars and electric locomotives. They also found use in static inverter stations and...
This is a day for hangovers and sunburns, discarded sparklers and spent rockets smoking weakly on brown lawns. Yesterday was all euphoria and patriotism — a chance to forget about the unemployment rate, the deficit, the oil spill and whichever political party you hold responsible for the country’s sorry state. But now it’s time to sit around in...
If you are reading this article on a printed copy of the Guardian, what you have in your hand will, just 15 years from now, look as archaic as a Western Union telegram does today. In less than 50 years, according to Clay Shirky, it won't exist at all. The reason, he says, is very simple, and very obvious: if you are 25 or younger, you're probably...
