Surrey NanoSystems is famous for creating Vantablack, a material so black that it absorbs all but 0.035 percent of visible light. That?s a lot. Things basically disappear when coated with the Vantablack carbon nanotubes. And yet, they?ve somehow made the material even blacker. Yes, the blackest black material has become even blacker.
Can't see the light from a laser pointer reflect from it.
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Mikek
Does it reflect RADAR?
I didn't see any mention of that.
I was wondering about solar collectors, all the light is reflected around in the nanotubes until all is absorbed and... turned to heat. Can we get all the heat to the back plate? They say it is very expense.
Mikek
On Fri, 4 Mar 2016 19:16:49 -0600, amdx Gave us:
You racy pig! :-)
Depends on the backing. The absorber has to be several wavelengths deep. Old UHF Russian radars saw some of our early attempts at stealth.
That's easy. You can't see a laser pointer on an LCD screen, either.
It would be good for making steam from cold water using sunlight.
Great, if they could eliminate the gigantic parabolic reflectors and Fresnel lenses.
Yep, political correctness sucks!
Mikek
Years ago one of my kids science class was doing solar energy projects. I came in with a Fresnel lens from a large screen TV. I had built it into a frame on legs. I started wrong, I melted a penny, the teacher got extremely nervous.
Mikek
That is what 100% efficiency solar cell would look like.
Would converting that heat to electricity make the collector more efficient than standard solar?
On Sat, 05 Mar 2016 10:46:43 -0800, Robert Baer Gave us:
Peltier has that covered. Needs power robbing air handling for heat removal from the cool side to work well.
Of course. It is illegal to deface US currency.
No, for solar thermal collectors you want a material that is black in the wavelengths produced by the sun (including visible) (like vantablack), but you don't want to lose that energy by radiating it off in the far-infrared (e.g. 10um wavelength). Therefore you want the material to be shiny (low emissivity) in the far-infrared at the same time.
You can already buy such a material, it is sold for making solar thermal collectors.
The extra tiny amount that you could collect by using a blacker material (vantablack) would be more than lost due to the vantablack probably also being too black in the far-infrared, and radiating away your power.
On Sun, 6 Mar 2016 21:20:06 +1100, Chris Jones Gave us:
It would likely make a very nice uniformly heated black body source for instrument calibration.
A thin covering of it over an Aluminum ingot would likely be better than the current ingot sprayed with matte black "IR Paint" method.
I used to make just such "ovens" for the NIST and other such customers for IR instrument calibration. Most have a 6.5" diameter ingot about an inch behind a 6 inch hole in the chassis to keep room air currents from messing with the surface temp uniformity (as much). The ingot surface had concentric pyramidal rings cut into it.
This stuff could simply be applied to a flat ingot surface.
I think a hole looking into a hollow sphere is nearly a perfect black body if I remember correctly from a physics book 35 years ago. That kinda makes sense.
On Sun, 6 Mar 2016 03:35:35 -0800 (PST), snipped-for-privacy@gmail.com Gave us:
heaters formed around a basketball with an alumina tube to site into it through that were that.
But for low temp stuff (relatively speaking) between ambient and about
and used by the NIST as well.
Colder stuff used water baths as a source.
Seems to be specifically allowed, in the case of pennies and nickels.
On Sun, 06 Mar 2016 07:34:09 -0500, Spehro Pefhany Gave us:
Cannot apply to pennies anymore at all, since the friggin things are electroplated zinc.
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