81–90 of 97 posts
Can someone explain this? "generators spin in a sealed atmosphere of hydrogen gas", hydrogen, really?
Hydrogen offers low drag and good thermal conductivity: http://en.wikipedia.org/wiki/Hydrogen-cooled_turbo_generator
Earlier quoted context omitted.
For a lot of infrastructure, the ability to more accurately model and calculate the performance of structures has meant that they don't need to be overbuilt so much. The less you overbuild a structure, the less it weighs, and the less structure you need to build - a virtuous cycle. If you look at the last 400 years of bridge design you can see the transition from overbuilt compression structures to gossamer suspensio…
I agree that there is a vast increase in productivity and saved resources from better modelling and understanding of the materials. But you cannot ever convince me that our steel suspension bridges are going to last for centuries like our stone bridges from the 15th century and onwards.
Didn't realize nuclear reactors were that inefficient . But I get most of my power from hydro, so that's perhaps an unfair comparison.
Earlier quoted context omitted.
Hydrogen offers low drag and good thermal conductivity: http://en.wikipedia.org/wiki/Hydrogen-cooled_turbo_generator
Why wouldn't they spin instead in a near-vacuum, instead of an environment of hydrogen?
> This paper's findings suggest that an arbitrary Chinese policy that greatly increases total suspended particulates (TSPs) air pollution is causing the 500 million residents of Northern China to lose more than 2.5 billion life years of life expectancy. The quasi-experimental empirical approach is based on China’s Huai River policy, which provided free winter heating via the provision of coal for boilers in cities north of the Huai River but denied heat to the south. Using a regression discontinuity design based on distance from the Huai River, we find that ambient concentrations of TSPs are about 184 μg/m3 [95% confidence interval (CI): 61, 307] or 55% higher in the north. Further, the results indicate that life expectancies are about 5.5 y (95% CI: 0.8, 10.2) lower in the north...
Nothing like it will be built again because a) successive British governments over the last 30 years have buried their heads in the sand over energy policy[1] and b) we as a country don't do actual engineering anymore. Both a and b mean that our energy future likes wholly in the hands of France! [1] Say what you like about Thatcher, at least she had a halfway coherent energy story.
"we as a country don't do actual engineering anymore" Let's see - within a few miles of Edinburgh we have being built: - 65000 ton aircraft carriers - A new 2700m road bridge over the Firth of Forth - Eurofighter work - A new railway being open to the Borders (OK - reopening an old line) OK, I won't mention our trams, but there certainly seems to be a hell of a lot of "engineering" going on in the immediate vicinity.…
Edinburg sounds a lot like Hampton Roads, VA, where we build lots of defense stuff, including the 100k ton Gerald Ford class nuclear carriers, with the largest gantry crane in the western hemisphere - fun fact, they hoist the island of the carrier onto the flight deck. Amazing engineering work going on there!
An interesting counterpoint, in being submitted on the same day as http://www.pnas.org/content/early/2013/07/03/1300018110 "Evidence on the impact of sustained exposure to air pollution on life expectancy from China’s Huai River policy" starts getting publicity: > This paper's findings suggest that an arbitrary Chinese policy that greatly increases total suspended particulates (TSPs) air pollution is causing the 500…
Earlier quoted context omitted.
For a lot of infrastructure, the ability to more accurately model and calculate the performance of structures has meant that they don't need to be overbuilt so much. The less you overbuild a structure, the less it weighs, and the less structure you need to build - a virtuous cycle. If you look at the last 400 years of bridge design you can see the transition from overbuilt compression structures to gossamer suspensio…
I agree that there is a vast increase in productivity and saved resources from better modelling and understanding of the materials. But you cannot ever convince me that our steel suspension bridges are going to last for centuries like our stone bridges from the 15th century and onwards.
By the 1940s, a stone bridge that might take 100 man-years of labor to create could be replaced by a bailey bridge that goes into place overnight. I'm sure if we wanted to create a bridge that lasts 300 years, we could dedicate more resources to it, but it would be grossly wasteful to do so - you don't know how long the current requirements are going to even be relevant. It's better to build a bridge that lasts for 50-60 years, and have the option value of replacing it with a better structure down the road.
One often gets the "nothing like this will be built again" feeling around these kinds of engineering projects from the 20th century, since modern constructions tend to have a very different feel, more sleek and less massive. Also true with things like transit infrastructure: even though a modern subway or elevated train line, like the Copenhagen metro (which has both), is better in just about every way from the old s…
"with their massive steel columns and hundreds of thousands of rivets" We have a fantastic example of that near Edinburgh: https://en.wikipedia.org/wiki/Forth_Bridge
An interesting counterpoint, in being submitted on the same day as http://www.pnas.org/content/early/2013/07/03/1300018110 "Evidence on the impact of sustained exposure to air pollution on life expectancy from China’s Huai River policy" starts getting publicity: > This paper's findings suggest that an arbitrary Chinese policy that greatly increases total suspended particulates (TSPs) air pollution is causing the 500…
Love your writing, but how is this a counterpoint? The article claims no more AGR reactors will be built. It's bullish on nuclear reactors in general.