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Conductive Concrete Offers Building Security
zdburke writes: "In a slightly different spin on the electromagnet-protected server room in Stephenson's Cryptonomicon, the folks at the National Research Council have developed concrete that conducts electricity, or 'percolates,' allowing it to serve as an electromagnetic shield. Current uses lean toward heated loading docks, non-freezing bridges, and grounding large-scale electrical equipment, but the counter-espionage idea is cool. The NYTimes has a brief story, and the folks at UN Omaha have some great pictures. It's not exactly new (it won a Popular Science prize in 1997) but it's still cool stuff."
I'm not a huge expert in the realm of physics (dammit, Jim, I'm a computer scientist!), but is this anything like a massive Faraday cage, which would prevent electromagnetic waves for entering and exiting?
:-)
I shudder to think of the day when we will work in protective buildings like these, keeping company secdrets safe from Van Eck phreakers and war drivers, but also keeping out the mellow, smooth sounds of Office Light Jazz 94.7.
Karma: Excellent Birds (mostly as a result of listening to Laurie Anderson)
I remember when a friend was recording a radio theatre show, the studio had chicken wire on all the walls (behind accoustic foam in most places) to minimize inteferrence from outside signals. You don't want your microphone cable picking up radio signals when recording a performance. This material could be ideal for construction in applications like that where you want to block out outside signals.
The most obvious use is heating.
But wouldn't it be cheaper and simpler to embed, say, a PVC 2-inch pipe in the concrete, and run warm water through that? Note that you can use this method with just about anything (dirt, asphalt, etc) and keep it from freezing.
If you want a method to directly heat it using electricity, run stainless steel pipe instead, and use it as a load.
I've frequently wondered why civil engineers haven't implemented either of the above techniques before. Chalked it up to "roads don't freeze enough".
Thoughts?
Don't sweat the petty things. But do pet the sweaty things.
Well for one thing where on earth is there going to be a road & highway department (in a country that can afford heatable concrete) that's going to let an inch of ICE fully form before they decide to do something about it?
For another thing two CM of ice is 12-40 CM of snow (depending on humidity). That's an awfully big dump for the majority of the world the majority of the time; most of the time in most of the world you'll be dealing with small fractions of this.
For another thing, why would you possibly need to melt all the ice that quickly (even assuming you were stupid enough to let that much form in the first place)? Why not just let the thing run at lower wattage 24x7 (when it is snowing, or at night)? It only needs to keep the snow that is there from refreezing, and to melt any new accumulation.
Finally, "assuming 100% efficiency" ?? So what? What if it's not 100% efficient? What else is the waste product going to be besides heat?
Actually, the concrete, if it is like normal concrete, would probably explode instead of melting...the little air pockets inside it expand until they break the structure. It's neat. Hold a blowtorch to some concrete sometime---it crackles!