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Military Develops Liquid Body Armor
kai5263499 writes "Military.com has an article about a new liquid body armor the U.S. Army Research Laboratory has developed. According to Dr. Eric Wetzel, the project coordinator: 'The key component of liquid armor is a shear thickening fluid. STF is composed of hard particles suspended in a liquid. The liquid, polyethylene glycol, is non-toxic, and can withstand a wide range of temperatures. Hard, nano-particles of silica are the other components of STF. This combination of flowable and hard components results in a material with unusual properties'."
"Polyethylene glycol (PEG) is a water-soluble, waxy solid that is used extensively in the cosmetic and toiletry industry."
c ol&sourceid=mozilla-search&start=0&start=0&ie=utf- 8&oe=utf-8
http://www.google.com/search?q=Polyethylene%20Gly
That's from the first link.
'Standards' in computing only impress those who are impressed by things like 'standards'.
its resistance to stabbing has to be called into question
According to the article: "Liquid armor is much more stab resistant than conventional body armor. This capability is especially important for prison guards, who are most often attacked with handmade sharp weapons."
How in hell did this post get Modded "Insterestng"?
If you really want to know: look here
BTW, that was the first hit in google.
"poly" changes it completely. Binyl chloride is pretty nasty (much much worse than ethylene glycol), but polyvinyl chloride is PVC and that's all over the place. Generally when you polymerize a monomer you are using up the reactive sites that would normally cause toxicity to form bonds with other monomer molecules. The same thing goes for a whole lot of other monomers.
Polyethylene glycol is actually really bio-friendly. Proteins don't stick to it well so it can be used in the body. You can even eat the stuff. I can't think of specific products, but I know it's on the ingredient label of lots of things we eat.
Yeah, it does quite a bit. PEG is used in shampoos and drugs all the time to make them nice and goopy.
EG is toxic because it's metabolized by alcohol dehydrogenase to form glycolic acid, causing acidosis (too much acid in the bloodstream), or various other nasty downstream products. PEG isn't metabolized, so it's safe.
Ethylene Glycol: C2H6O2
Polyethylene Glycol: C2H4O
So they are pretty different from a chemical standpoint. Good old Ethylene Glycol melts at -13C, while the "poly" melts at 60C. However, when looking up an MSDS on this stuff, I get "May act as an irritant. Toxicology not fully investigated" so I wonder about it being completely non-toxic.
See link here.
Polyethylene glycol is found in a lot of cosmetics and even some foods. It is sometimes used to treat constipation. Remember, Google is your friend.
How am I supposed to fit a pithy, relevant quote into 120 characters?
And is used as a major component of both cough syrup and paintballs...
Yes, it does. Or at least can, I don't know about this specific case. Ethylene Glycol has an ethylene functional group in it, which is characterised by a reactive carbon-carbon double bond. That reactive bond is almost certainly related to its toxicity. The poly in polyethylene glycol refers to polymerization. In this process, that double bond is converted into a single bond, and attaches on either end to another ethylene glycol molecule, creating a long chain of single bonds, which are far less reactive and quite possibly nontoxic. I don't know about PEG in specific, but a modest knowledge of polymer chem suggests that is what's happening. I'm sure someone can correct me if I've got it wrong, though.
[Fuck Beta]
o0t!
Absolutely.
Ethylene glycol is OH-CH2-CH2-OH and is fairly toxic. I would suspect it behaves similarly to ethanol (CH3-CH2-OH) in the bloodstream, but I don't really know. Contrast this with propylene glycol, CH2-CH2-(CHOH)-OH which is pretty much completely non-toxic.
Polyethylene glycol is (-CH2-CH2-O-)n, where n is some large number. It's a polymer. There are different kinds of PEG, but glancing at the web, there appear to be a number of different kinds available, and they appear to be reasonably non-toxic.
that is exactly the parent's point. If its stab resistant how can it also be sewable. Since sewing is essentially stabbing a piece of cloth with a needle that has some thread going through it.
My days of not taking you seriously are certainly coming to a middle...
Yes, this is the same type of process. Fluid when handled gently, but it becomes rigid when subjected to a sharp impact.
If you jab it, it feels hard and your finger won't go in very far. You can pour it slowly, but you can grab a clump of it, almost as if it's a solid. This kind of fluid is called dilatant. It becomes more viscous when agitated or compressed.
The cornstarch mixture is sometime called ooblick.
Sadly this invention was too late to save Pat Tillman. Armor like this could save lives, and that's what it's all about. I'm all for it.
The dangers of knowledge trigger emotional distress in human beings.
Does the "poly" really change it all that much?
In a word, yes. Here are the Material Safety Data Sheets for both chemicals:
ethylene glycol
polyethylene glycol
I like my beverages with warning labels!
Your instructor was talking about the hard Kevlar for the PAGST helmets. Kevlar vests (which ironically usually aren't Kevlar anymore, rather some kind of Aramid fiber) are still a lattice or weave of fibers. They work on two priciples 1) Extending the moment of impact by stretching out, and 2) by spreading the force of the impact across a wider area. When a bullet hits a "Kevlar" vest, the vest doesn't stop it cold instantly, rather the vest fibers stretch and entangle the round and slow it's progress. (The vest and bullet do actually move back into the body cavity slightly, but not enough to do permanent damage).
The current limiting factor with soft armor is that it won't stop a rifle round (Due to its extreme speed). So to provide protection to NIJ III+ or IV levels (i.e stopping rifle rounds) hard armor plates (usually a ceramic and titanium composite) are inserted in over vital areas.
The advantage of the liquid armor is that much less fabric will be needed to provide the same level of protection, and the hard armor plates won't be necessary.
Hit www.galls.com 's body armor section for more info on levels of protection and whatnot.
-E2
(BTW: Shadowrun had the liquid armor idea waaayyy before Snow Crash came out.)
The evil monkey commands you to dance.
For a scientific paper on the subject, see Advanced Body Armor Utilizing Shear Thickening Fluids, by Y. S. Lee, R. G. Egres Jr. and N. J. Wagner, all of the Center for Composite Materials and Dept. of Chemical Engineering, U. of Delaware, and E. D. Wetzel of the Army Research Laboratory, Weapons and Materials Research Directorate Aberdeen Proving Ground.
For a University of Delaware Press Release (with photos), see here.
Only Women Bleed (Sex, Sharia remix)
The reason flack vests were invented was to protect against shrapnel wounds. During the second world war, a lot of data was accumulated about combat injuries, and it was found that a lot of casualties were caused by shrapnel. Shrapnel is generally low-velocity, as opposed to rifle bullets so flack vests aren't too good at stopping high velocity projectiles. The fact that the vests stopped (low velocity) pistol rounds was just a nice side effect, since during a war, you don't often employ pistols. Police agencies loved it though. Thus was born the flack vest.
http://en.wikipedia.org/wiki/Non-Newtonian_fluid
I can't believe that no one has mentioned the books by Larry Niven. I forget which one, exactly, but somewhere he describes armor almost exactly like this. It's soft and flexible, until you hit it, and it becomes very hard.
Beware of he who would deny you access to information, for in his heart he dreams himself your master.
Not only is it "non-toxic", but it's an ingredient of one of my favorite carbonated beverages, Dr Pepper.
For example, in urban combat, you are constantly looking up, and pointing your weapon up. As you crane your neck backward and move your non-firing hand above your head, with a traditional kevlar vest you reach a flexibility limitation. If you then have to contort your body laterally for some reason (and they always arise) your trunk is limited in flexiblity as well.
A vest that could incorporate greater flexiblity and some sort of heat-dissipation mechanism would be a real boon to soldiers who need body armor protection.
Read the EFF's Fair Use FAQ
All but one of the guys who dropped the nukes committed suicide. 3:250000. Respectable I suppose.
Slashdot is proof that Sturgeon's Law applies to mankind.
The main reason that Ethylene Glycol is toxic is that a metabolic byproduct is glycoaldehyde, a close relative of Formaldehyde, the acidosis is bad but would rarely be fatal on its own. The treatment for Ethylene Glycol poisoning is Ethanol ingestion because "Ethanol will competitively inhibit alcohol dehydrogenase", so if someone ingests EG give them a glass of Vodka and take em to the ER for observation.
There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.
Another scientific paper on the subject: "The ballistic impact characteristics of Kevlar (R)
woven fabrics impregnated with a colloidal
shear thickening fluid," JOURNAL OF MATERIALS SCIENCE 38 (2003) 2825 - 2833.
Only Women Bleed (Sex, Sharia remix)
This is straight off of Army News Service.
And they even have a picture!
As I understand the science, the kinetic energy of the bullet causes a state change in the material. It gets hard. It dissipates the energy (most likely as heat) and returns to its liquid state quickly.
--AC
at certain stages of metabolism, both of the products you and the parent poster mentioned are formed.
In years past, the only treatment was competitive enzyme inhibition via an alcohol drip (that's still the treatment in some places)... though fomepizole (Trade name is Antizol, I believe) is the safest treatment now, and a hell of a lot easier to get than persuading the pharmacy to mix up an ethanol drip.
Ethylene Glycol is a nasty poisoning... and thankfully not that common. I'm pretty thankful that I haven't taken care of a case of that in a few years.
Even if a man chops off your hand with a sword, you still have two nice, sharp bones to stick in his eyes.
of PEG... it's called Golytely... here's a bit of info.
It's commonly used by gastroenterologists to clean out the colon prior to endoscopy. You have to drink an entire gallon...it's usually referred to as a "bowel prep."
To those of us familiar with it, it's also affectionately known as "GoHeavily," "GoFrequently," or "GoEndlessly." I've also seen it used to treat bad constipation... ingestion of the required amount virtually guarantees an impressive "code brown."
Yes, I realize that's waaaaay more than you wanted to know. Sorry.
Even if a man chops off your hand with a sword, you still have two nice, sharp bones to stick in his eyes.
That was Dune, yes. Although this stuff reminds me more of Niven's "impact armor", a sort of jumpsuit that would go completely rigid upon impact. Padding on the inside would shield your body from the transferred kinetic energy. If the impact was localized, the rest of the suit retained mobility. With a full suit of this stuff it was possible to fall off a small building and land on your head. You'd be jostled and have a mild concussion, but you'd be alive and able to walk away in one piece.
End of lesson. You may press the button.
You're confusing Polyethylene Glycol with just Ethylene Glycol, which does taste sweet and dogs often lick up puddles of it as it is in antifreeze and ends up on driveways. Not good for fido.
-- What I don't have in intelligence, I make up for in a lack thereof.
Erm, wrong. Most antifreeze is Ethylene Glycol, not Propylene Glycol nor Polyethylene Glycol. Propylene Glycol is often found is candy and is the liquid used to make fog in fog machines.
-- What I don't have in intelligence, I make up for in a lack thereof.
My experience with MSDS sheets is that if it doesn't say it will rot your arm off, it's probably pretty damn safe. They try to cover all the bases, and relatively everyday materials wind up sounding alarmingly dangerous... Of course, you ought to check a MSDS before handling any material you're unfamiliar with -- but with a large enough grain of salt that you don't wind up paranoid of toching sand, or something. Seriously, look sand up -- dangerous stuff. :)
At least when they were new (dunno if it's changed, but don't really see how it could -- everybody in the GPs and WSB and AMA still wears leather, afaik), the big knock against the kevlar suits was that their coefficient of friction was too low -- you'd slide until you hit something immovable (guardrail, car, etc.). Wrapping yourself in cow is still just about the optimal compromise between slowing down quickly enough and not catching and starting to tumble.
:-)
Moo.
HO-CH2-CH2-OH
The repeat unit of polyethylene glycol looks like this:
-CH2-CH2-O-
So with polyethylene glycol, just attach that unit end-to-end over and over again. How many repeat units you have in the polymer will determine the melting point and many other properties. The MSDS you link to is for PEG-8000, which probably means it has a molecular weight of 8000.
Incidentally, you'll notice that the ethylene glycol unit (the monomer) is different from the PEG repeat unit by an H2O -- water is a byproduct of the polymerization.
Polymerization does make a huge difference in properties. Polyethylene is basically ethane (or, if you look at it another way, methane) attached end-to-end, but polyethylene, of course, is very different chemically from methane.
Finally, I get to post to Slashdot about a technical subject I know something about. Quick, someone, mod me up! It may never happen again! :)
PAG is definitely a glycol (poly-alkaline glycol) and is the recommended lubricant for basically all R-134a sytems. However, ester oil works just as well and is cheaper, as well as working just fine for R-12. One inexpensive product to carry makes life much easier.
Engine coolant is definitely glycol-based as well, and in some cases it does get pretty hot...
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
Actually, no, it doesn't.
(Very) brief lesson in fluid dynamics.. Newtonian fluids obey this "law:"
Shear stress = - viscosity * shear rate.
Imagine you have two panes of glass. You lay one out horizontally and pour a layer of liquid on to it (we'll pretend it stays on and doesn't run off onto the floor). Then you place the second pane of glass on top. You apply a constant, horizontal force to the top pane of glass, and it begins to move at a certain velocity.
shear stress = the force * the area of the glass
shear rate = the velocity / the distance between the two panes (not really, but close enough for our example)
Fluids with viscosities that don't depend on the shear rate are called Newtonian. Water is largely a Newtonian fluid. It's viscosity depends very strongly on temperature, but not much on shear rate. Doubling the shrear stress (the force) would result in a doubling of the shear rate.
Ketchup is a good example of a non-newtonian shear-thinning fluid. If you put ketchup between your glass panes, you'd find that smaller and smaller amounts of additional shear stress are necessary to increase the shear rate by equal amounts. This is easy to understand, b/c our everday experience with ketchup tells us that it can take a big shock to get it moving, but once it goes, it goes quickly. (The viscosity is high at low shear rates, like when it isn't moving, and so a lot of shear stress is required. Once it starts, the shear rate goes up, the viscosity decreases, and less shear stress is needed).
The fluid in these vests is the opposite of ketchup. It is shear-thickening. At the shear rates the armor is subjected to in ordinary movement, its viscosity presumably remains low, allowing the soldier to move. But when someone tries to stab through it (a fast, high shear movement) it thickens (its viscosity increases) and the blade/bullet/whatever is stopped.
I don't know how the stuff is sewn, but it could be sewn slowly without a problem. Remember, it's shear rate that makes it thicken up.
In my admittedly biased American oppinion, the people who have arrogance problems are the rest of the world.
Oh right, of course. It's EVERYBODY ELSE that's got the problem. Newflash: When all your friends start acting weird, it's not them that have lost the plot.
Forget thrust, drag, lift and weight. Airplanes fly because of money.
Obvioulsy you've never sewed before. Sewing isn't stabbing, it's fitting a needle in between threads of the fabric.
First, assume that your knife has a point that is to sharp it does fit between a couple of threads of the fabric. Next, when you push it farther in, it must cut the fabric or spread it apart, otherwise it won't go any further. I don't know of a knife that sharp that can hold an edge, so the first thing you'd have to do with the first stab is break a few strands of thread so you can start sliding in and cutting. (Yes, I realize the cutting itself is affected by the amount of force behind the blow)
Sewing and stabbing are two completely different actions and are not comparable in any way.
Like what I said? You might like my music
Exposing a metal structure (Let say, a tank) to a large dose of neutron radiation, makes it radioactive. FAFAIK A neutron bomb is a standard nuke without the depleted uranium shield to keep the neutrons inside the bomb until the bomb blasts apart.
It was designed as a countermeasure against the vast numbers of Soviet tanks. There were some places in Europe where those tanks would need to drive close together to pass and if a neutron bomb would be detonated above those tanks, it would turn the invading armor devisions into radioactive metal and death bodies.
in 1967 and 1968 at Ohio State University, I researched and used this property of thixotropes as both an acoustic coupler and as a high-pass filter. My department (Welding Engineering) was doing research on non-destructive testing of concrete highways -- contractors got paid for the average depth of the concrete emplaced, (nominally nine inches) and that had always been tested and documented with core samples.
.5 microsecond pulse gives a long train of harmonics athat were not only not useful to my purpose, but were, in fact a distraction.) It also filtered out the low frequency multi-path reflections within the concrete.
We attempted to do it with a sonar method. Basiclly, we whacked the concrete with a half microsecond, 2Mhz pulse from barium ferrite crystals mounted rigidly in a big aluminum ring, and measured the time in and out.
Problems were the aggregate nature of concrete, impedance of the interface, and both physical and acoustic coupling in and out.
I discovered that a tube of a hair grooming product called "Groom and Clean" rang when tapped. Curious as to why, and having all these neat acoustic toys to play with in our lab, I discovered several things.
First, what thixotropes are, (Groom and Clean was primarily methyl cellulose suspended in water) second, what other similar materials existed, third, what cheaper materials were available (bentonite) and what the stuff was good for.
All thixotropes have the property of flowing like liquids when moved gently., and acting like glass when shocked. IOW, you can stir it, but if you fire a projectile at it, or simply whack it with a hammer, it will shatter like flint or a big chunk of glass in a characteristic 'conchoidal' fracture. the key feature is though, that it *immediately* slumps into a liquid again!
OK, why is this? The composite material is small flakes of a wettable, but insoluble crystalline material. In bentonite it's plain old ordinary kaolin type clay, with a particular sheetlike structure. When this is wetted, and suspended in water, (I found early on, that plain old antifreese worked better, but I had trouble enough squeezing any cash out of the administrator, without having to beg for a 55 gal drum of propylene glycol), the result is just a big tub of gray glop (bear in mind these are all scientific terms of art.)
A projectile, or more to the point, in my research, any fast-onset shock, turned the plates up on edge, more quickly than they could flow out of the way of each other. The flakes, in touching each other, produced a temporary rigid matrix that acted like glass, or flint (both super-viscous liquids)
In retrospect, the intuitive leap required to soak a fabric in this stuff, and use it as armor should have been obvious, but it was not the focus of my interest, or needs. Oh well, the University would have had patent anyway, since I was just a lowly bench researcher
At any rate, the end result was that I could use it as a pysical acoustic coupler (the gooey characteristic) under my big aluminum ring, and and the glop also acted as an impedance transformer for the 2Mhz 'bong' from the piezo-electric crystals, because very high frequency pulses would pass through, selectively, more easily than the low frequency rumbles and internal reflections from inside the aluminum block. (a Fourier analysis for a single
The receiver, in a close fitting hole in the ring, got slathered on the sides and end with the bentonite as well. Before the drillers mud improvements, our oscilloscope had a lot of 'grass' that made spotting the echo difficult, and often times impossible. Knowing the mean trasnmission times thruogh various types of concrete was helpful, but not definitive. Our new ability to clean up both the input signal (the bong!) and the received echo made the return signal much more obvious in the now much reduced 'grass' on the oscilloscope.
I had previously worked with concrete (as the scion of a big readi-mix c
I'm armed and I haven't changed my patch, so don't start with me -- you *know* how I get!
From what my grandfather, a retired US Army E-9 told me, the major benefits of the Neutron bomb were that the radioactive materials created from the detonation of a Neutron Bomb had extremely short (In Terms of Radioactives) half-lives. So you can drop one on a country, then move in when it cools down. Also, the Neutron Radiation caused water to boil, which will destroy wood, concrete, paper, et cetera, et cetera. I'm guessing, though I'm no Physics Major, that it would also probably destroy the oil.
Edward@Tomato - /home/Edward/ man woman
man: no entry for woman in the manual.
"Qua!?"
Right. And the Palestinians so obey the laws. Really. They accept the roadmap unconditionally on the condition that they don't have to dismantle terror organizations. I am tired of hearing how everything is Israel's fault and none of the Palestinians. History showed differently. How many countries has Arafat got booted out for involvements in civil wars? Many people who just blame Israel know no history at all.
It takes one to make war. It takes two to make peace.
Israel has offered 95% of the territory. Where was Arafat's counter offer?
Disclaimer: No, I am not a Jew, an Israeli, a zionist nor an American.
Here are some references:
Showing the 45% figures
In graph form
When you look up figures, how fresh they are are vital. The Iraqi and Afghan war has substantially boosted the USA military spending.
Unless the US's GDP is THAT much higher than the 46 countries above us, your facts are wrong.
The answer to that is yes. The US GDP is indeed that much higher than most of the 46 countries above you (except China).
Another possibility is that the CIA is biased (or incompetent). As their recent record in Iraq shows, their intelligences obviously isn't that great (unless you reckon they deliberately mislead the public). See the discrepency between their figures (that US spends $280B/year and the other figures $420B/year. Part of this is also probably because the Afghan, Iraqi and war on terror figures haven't made their way into the CIA factbook. Military spending in dollar figures.
Anyway, my central contention holds, that the fear by Roosevelt of the military-industrial complex has become a fact. That such spending will over time lead to China, India, Indonesia and Europe increasing their spending without necessarily buying security for anyone -- you, me, the citizens of USA or other countries. We all lose, this is MAD. (pun intended)