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Lightweight Radiation-proof Fabric?
kramer writes "New Scientist is reporting the creation of a lighweight radiation-proof fabric called Demron. Demron is being touted by its inventors as comparable to lead shielding at a fraction of the weight. Could be very useful for any future interplanetary space missions where the amount of radiation absorbed by the crew is a significant concern."
"The molecules are lined up to give the illusion of the presence of large atoms," says Hefler."
And hence the illusion of being protected...
What were you expecting?
I'm sure you meant the fabric takes up less volume, as I would hope that weight is not an issue in space.
Weight might not be a big issue once you are actually in space, however, it is a huge issue when it comes to getting there. The currently used number for launch price is around $10000 a pound to get into low earth orbit.
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So I guess we no longer have to worry about losing our magnetic field then?
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It seems reasonable that that gamma radiation (high energy photons) could be intercepted by a 'cloud of electrons' in the polymer in this material.
However, high energy neutrons would not interact with the electrons due to their high velocities. The relativistic effect of width/length contraction applies to these neutrons. This was the fundamental problem of early fission reactors - they had to moderate (reduce the speed of) the neutrons in order for them to appear big enough to interact with a nucleus. An electron is 1,836 times less massive than a proton. Thus you'd need 1836 electrons to equal one proton-with of neutron blocking power. I doubt they have that many electrons in the polymer's cloud!
However, any material that more effectively screens high energy photons is a welcome material. It would also be highly useful in creating X-Ray and Gamma-ray telescopes, methinks! NASA, you listening?
The article should have gone into which radiation types besides Alpha particles that it would block (Alphas I think are just Hydrogen nucleii - or is it Helium...).
Cosmic ray shielding would be useful on the ISS as well, but it would not stop relativistic particles, and it might break down under repeated insults of high energy collisions occurring regularly in space.
Any nuclear engineers out there who can comment better? go Navy?!?
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The researchers say it's comparable to lead shielding in terms of shielding radiation, but this does not quite address an important concern. Is it like lead shielding only with respect to nuclear radiation? Or x-rays and such as well?
I'm only asking because I'm trying to figure out whether Superman can see through it. Any help is appreciated.
-Lex.
Anyone know if a pair of pants made of this will set off the Airport metal detectors?
Can I stuff a duffle bag full of guns and make them not show up on that little thing?
For the cost it probably wouldn't be worth it though.
THERE IS NO DATA. THERE IS O
Low-energy alpha & beta are easily blocked with century-old technology. Their explanation of how they block X and gamma sounds like smoke & mirrors to me.
BTW, '0.00% of gamma gets through' may be worse than nothing, since the secondary shower (from whatever the gamma ray hit) is often worse than the gamma.
It's easy to make up & spread cool- and credible-sounding stuff. Finding & checking hard facts is hard work.
However, if this does pan out, it will probably help with the radiation issues they are currently having aboard the ISS. I would like to see lightweight fabrics, and other lightweight materials for that matter, become more prevalent in the future - as long as they are durable and protective! This is one important way we will be able to increase fuel efficiencies and with any luck see long-range space travel in our kids' lifetime.
I think with the interesting people, their lives can't possibly be wrapped up into a nice little package.
I can finally look fashionable while thwarting the cia's mind readers instead of that baked potato look I had going for me.
Interplanetary space missions? Uh, that's great. I'll be looking for a cell phone case made out of this stuff. And boxer briefs, of course.
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So when are they going to start making tighty whiteys outa this stuff I have to drive past a nuke plant everyday and I still want to have kids!
If you're that concerned about having kids, then why are you still wearing tighty-whiteys? Your body heat is doing more to drop yer counts than that power plant!
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Cell phones emit microwave radiation if I recall correctly (non ionizing radation regardless), aluminum will stop that. But thats not the point, the radiation if coming from the antenna. If you block that you cant transmit (or receive for that matter.
If you are really that woried, just wear your tin foil helmet. It will "protect" you.
Im not here now... Im out KILLING pepperoni
I was a Navy nuke, so I know a thing or two about radiation. What people think of as "radiation suits" are not designed to shield radiation. They are used to prevent contamination. The suit prevents radioactive material from getting on your skin and clothes, so that you don't take it home with you. There are several kinds of radiation. Alpha particles are helium nuclei (He4). These particles are not dangerous unless you ingest or breathe them into your lungs. The dead layer of skin on your hand is enough to stop them. If they get into your body, they cause serious harm, as there is no "dead layer" of anything to stop them. Beta particles are electrons. They are light and fast, so they penetrate more. They will give you a dose to your skin, but not much deeper than that. A contamination suit can probably stop Betas. Even the old ones. Gammas are photons/electromagnetic radiation. Whatever you want to call them. X-Rays, microwaves, and radio waves all fall into this general category. The real biological hazard comes from the high energy particles/waves. These will pass right through your skin and can affect your internal organs. A contamination suit is not expected to reduce the dose from gammas. neutrons are produced in fission and some rare decay events, mostly shortly after a fission event. Neutrons are the only thing that can make something ELSE radioactive. Neutrons have no charge, so shielding them is difficult. It takes LOTS of lead or iron or water, etc. I don't care what their material is made of, if it's light enough to wear, it will not shield neutrons well. The web site said that it shileds low energy gammas, alphas, and betas. Low energy gammas don't cause much harm. Unless you work with a low energy gamma source on a routine basis, this material is not going to change your life. Or your life expectancy. This is my first post. Is it WAY too long? Sorry. -John
I hope it comes in all kinds of gawdawful pastel colors so airlines can make nifty new uniforms for their flight crew.
The article doesn't mention anything about the secondary emission characteristics of this fabric.
Secondary emissions are a very real bane of shielding for interplanetary travel, due to the extremely high energies of cosmic rays. Even if you could launch lead shielding for a spacecraft, manageable thicknesses would cause secondary emissions that were even more dangerous to the occupants than the original cosmic rays.
They've tried a new type of radiation shielding on the ISS made of polyethylene that is supposed to block without creating secondaries, and I see that's part of this fabric. Unfortunately the new shields don't seem to be as effective as hoped.
Radiation is anticipated to be a big problem on a Mars mission. IIRC, the radiation exposure will have a cancer risk equivalent to a lifetime of smoking.
But you really know to be scared of cosmic rays if they make rapping noises on your spacecraft, and upon return to Earth you start stretching, bursting into flame, become invisible, or turn into a pile of muscular orange bricks.
The living have better things to do than to continue hating the dead.
To make clothing out of for those of us who live in areas that could potentially be hit by dirty bombs!!!!!
--psy
huzzah! now when the magnetic field of earth changes polarity and it dissapears for some time, we'll all be safe wearing our Demron jackets. I'll be the first to sell Demron Letter Jackets for highschool football teams!
moox. for a new generation.
I checked out their website a few days ago and as you've noticed, it has no details. You can get an idea of the technology from their granted patent (amended) 6,459,091 here. The idea in the patent is to impregnate cloth with a heavy metal such as barium salt, with a metal film layer or cloth woven from metal thread for additional protection. The technology mentioned in the New Scientist article sounds like a newer version that is still pat. pending. There's still no hard information about how well the suits actually work for the different radiation sources, e.g. Medical x-rays, airline cosmic rays, nuclear warfare. It's all marketing.
- Throw away your alarm clocks and wrist watch, the glowing hands give you 0.6 mrem/year.
- Or try giving up bananas, most people recieve about 40 mrems/year per year in Potassium-40 radiation
- But the absolute worst source of radiation, cigarettes- 1.5 packs per day = 8000 mrem/year
- And move away from coal fired plants; Uranium occurs naturally in coal, which when burned exposes you to 1-4 mrems/year
All thanks to having a girlfriend at a national lab (which probably means she radiates more than your wifeSig Nazi- "No Sig for you, come back 1 year."
> Strength, high density of electrons, flexibility
> (similar to tire rubber), and wearable?
Just like a plastic bag. And just as effective.
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
Check out their "test results." (PDF file) Go to page 3 to see the blocking power of their fabric.
Error #1: There is no such unit as a Kv. They mean KeV, as in Po-210 emits an alpha particle with 5,300 KeV of energy. But this is minor.
Error #2: X-rays and gamma rays are both photons; they're only distinguished by their energies. But the X-ray results and gamma ray results (which overlap in energy, which, in itself, makes no sense) contradict each other. For example, why does the fabric block only 52% of 60KeV gamma rays, but 82% and 72% of 50 and 70KeV X-rays respectively? Makes no sense, but this is nothing compared to...
Error #3: The real killer, and what makes me suspect this is fraud, rather than mere incompetence. They use 0.5 mm of lead as the comparison for their gamma emitter tests. The radiation-absorbing properties of lead are well known, and easily accessible in handy-dandy tables. For example, the half-value layer (the amount of material needed to block 50% of incoming radiation) for a Co-57 source is 0.15 mm of lead (ref here ), so 0.5 mm of lead should block more than 90% of the radiation, not just 52%. Proof positive that they're full of shit.
Fuck them, and fuck New Scientist. (Pardon my French.)
Heavy nuclei tend to stop particles, like alphas, betas, and neutrons, but electrons are opaque to em radiation like x-rays and gamma rays. So the "heavy nuclei, not electrons" is incorrect. But the argument remains the same.
and I meant "...why does the fabric block 100% of 60 KeV gamma rays, but only 82% and 72% of 50 and 70 KeV X-rays respectively?"
This stuff may really be a godsend to alien abduction victims. You could make hats out of it, and they wouldn't look silly like the tinfoil variety. It could also work for disabling the V-chip. How soon can I start a business selling this stuff?
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Tell that to the 5 inch tumor on my head. *POP* Oh wait, it was just a pimple.
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WWJD.... for a Klondike bar?
Where did you hear that? X-rays can indeed be man-made, but they are natural as well. Hence the X-rays that Chandra (the X-ray telescope) detects.
Even if you are right, there is still no difference in the photons themselves. We are talking about electromagnetic radiation, for which the only real defining characteristic is the energy (frequency, wavelength, and energy are all determined by each other). If the energies of the reported gamma rays and the energies of the so called X-rays overlap and the absorbency is way different, I would have to agree that these people are indeed full of shit, and that New Scientists does indeed deed to be f*cked.
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Maybe they can sell a bunch to India and Pakistan,
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