[HN Gopher] "Off switch" makes explosives safer
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"Off switch" makes explosives safer
Author : Someone
Score : 77 points
Date : 2023-03-21 16:07 UTC (6 hours ago)
(HTM) web link (physics.aps.org)
(TXT) w3m dump (physics.aps.org)
| Animats wrote:
| Safe until filled with water is probably not that useful. Water
| is everywhere and things in military use tend to get wet.
|
| There are binary explosives now, where both components are
| nonexplosive by themselves. Those are used commercially, for road
| work and such.
| exabrial wrote:
| Ah, yes, but think those olive drab steel Ammo Cans. These are
| a simple, cheap, tried-and-true tested method of preserving
| military supplies; heat proof, water proof, dust proof,
| (somewhat) nuke proof, biological proof, and fire proof.
| londons_explore wrote:
| Depends how it's designed. If it needs to be drenched to be
| explosive, then simple drains holes at the bottom keep it safe.
|
| Plug the holes and fill with a hose when you want to use it.
| andrewflnr wrote:
| Yeah, damp or drizzle isn't going to activate these, if I'm
| understanding them correctly. If anything, I was wondering at
| first how they were going to deal with air bubbles (but I
| suspect they're fine as long as there aren't too many).
| tomatotomato37 wrote:
| I believe this is more intended for civilian (mining,
| demolition) or combat engineering explosives than it is for
| actual armaments, where having to have lots of watertight
| storage available to store your low density explosives isn't
| that big of a concern.
| nullc wrote:
| > where both components are nonexplosive by themselves.
|
| in plenty of binary explosives the components are explosive,
| but less so and even harder to set off.
| chillingeffect wrote:
| Those are the names of Javascript libraries right?
| EamonnMR wrote:
| Water has a tendency to get into places it's not supposed to. I'd
| hate for a roof leak to cause a warehouse explosion.
| etskinner wrote:
| Presumably there would be more safeguards in place than just
| the water. All the safeguards that currently exist could still
| be used.
| exabrial wrote:
| > They used a 3D printer to produce......
|
| Wow really upping the pucker factor in one of my favorite
| hobbies.
| flangola7 wrote:
| You wouldn't download a shaped charge
| smilespray wrote:
| Tip: Don't heat the print bed when printing with TNT.
| jabl wrote:
| I recently read about the Oppau disaster
| (https://en.wikipedia.org/wiki/Oppau_explosion ), where the
| workers were getting bored with using pickaxes to break up a
| huge pile of compressed ammonium sulfate and ammonium
| nitrate, and decided to use dynamite to loosen it up. What
| could possibly go wrong?
| jandrese wrote:
| The crazy thing about that is they had broken up the
| Ammonium Sulfate/Ammonium Nitrate mixture thousands of
| times before the incident. It was incredible that they
| managed to do so for as long as they did. All it took was
| one day where the mixture wasn't mixed very well and
| everyone dies. An industrial version of Russian Roulette.
| Xylakant wrote:
| It was considered safe at the time because the mixture is
| usually not very sensitive. Hindsight is 20/20.
| renewiltord wrote:
| Famous saying in Safety Engineering: everything that can
| go wrong will go right most of the time.
| nibbleshifter wrote:
| Its melt castable and not the easiest thing to get going, so
| you probably _could_ print with it.
|
| Probably would also give you megacancer.
| wongarsu wrote:
| Apparently TNT melts at 80degC. If we are to believe [1],
| liquid TNT is quite sensitive while confined, and gets more
| sensitive the hotter it gets, but if allowed to flow it's
| actually very difficult to set off. Autoignition happens at
| about 265degC, according to [2], and again according to [1]
| temperature doesn't play a major role in the sensitivity of
| solid TNT.
|
| So I guess don't heat the print bed too much, and if you do
| make sure the TNT can flow freely until it solidifies again,
| and you should be fine.
|
| Edit: and as nibbleshifter suggests, you could print with it
| given these parameters, just be careful with the TNT in the
| hotend.
|
| 1: https://www.cdc.gov/niosh/mining/userfiles/works/pdfs/itas
| s....
|
| 2: https://www.govinfo.gov/content/pkg/GOVPUB-C13-36e8df81dfe
| 03...
| Arrath wrote:
| There are to this day many an explosive product that is
| cast by pouring molten explosive material into the shell.
| In some cases, poured by hand from jugs.
|
| Steady!!!
| dsfyu404ed wrote:
| Would be pretty cool to be able to order custom shapes
| SendCutSend style. Would be real useful in demolition and
| construction settings in cases where you don't do enough of
| a specific job to buy or rent expensive non-explosive
| equipment to do it.
| TylerE wrote:
| That's easy with plastic explosive. It's a putty like
| consistancy. It's explicitly designed to be sized and
| shaped in the field.
| loufe wrote:
| I work as a drilling and explosives engineer at an active mine. I
| don't see the value-add here, to be honest. Modern explosives
| management (in a mining context) is extraordinarily well managed.
| ANFO (ammonium nitrate fuel oil) which is the dominant explosive
| type is so hardy that you can hold a flame to it or shoot it with
| a firearm and you will not succeed in detonating it. 3-stage
| explosives systems (detonator-->booster-->ANFO) is a fantastic
| way of managing risk. Detonators cannot set off ANFO, the booster
| is required middle step.
|
| I won't pretend to have studied the phenomenon, but the only
| undesired detonations I've heard of so far in my career have all
| been a result of detonators inadvertantly set off. The latest
| examples I know of being wireless electric detonators (which are
| being phased out as they're inferior to electronic
| detonators,which offer more protection) set off because of
| malfunctioning devices emitting the required radio waves, yikes!
| The explosion in Beirut can hardly be considered in the same
| category as that was an explosion of explosive precursor,
| effectively unrelated.
|
| I'm struggling to understand what the target market for this type
| of innovation is. Is it bulk transport of explosive materials
| between the manufacturer (like Orica or Dyno-Nobel) and
| individual mine sites? That part is already extremely safe. You'd
| need specialized equipment at each mine to mix the water back in,
| with maintenance and calibration requirements. There's no way
| this could be between the surface and the holes into which the
| explosives are loaded, for so many reasons. I also wonder about
| the consistency and quality of the resulting product, the balance
| for these explosives is already such a tuned and precise.
| killjoywashere wrote:
| Ah, Los Alamos, exactly what I though. What this really is, is an
| external manifestation of the eternal struggle between the
| military, which wants the weapons to detonate on time every time,
| and the safety-minded engineers and politicos who would rather
| eat an occasional fail than start a nuclear war. The safety
| people being the engineers tend to keep finding new ways to be
| safe and applying them without necessarily securing the DoD's
| permission, but they don't always work out the way the engineers
| intended. For a period of time, there was a piece of cobalt tape
| on Trident missile warheads that would ensure they fizzle unless
| removed. Except the adhesive dried up and then the release force
| exceeded the torque of the motor intended to remove the tape, so
| something like 75% of the Trident missiles were duds for years.
|
| Read Eric Schlosser's Command and Control. Absolutely
| fascinating.
| XorNot wrote:
| > who would rather eat an occasional fail than start a nuclear
| war.
|
| A nuclear detonation on allied territory that originates from
| your own weapons isn't going to cause a nuclear war. The point
| at which a nuclear warheads needs to explode is "when it's
| about 1km above it's target". The war is already _happening_ if
| it got anywhere near there.
| perihelions wrote:
| I can't find anything on Google about cobalt tape or Trident
| missiles -- but there was a cadmium wire in the W47 warhead,
| the one for Polaris missiles, which has a story very similar to
| yours:
|
| - _" Because the test ban prohibited the testing needed for
| inherently safe one-point safe designs, a makeshift solution
| was adopted: a boron-cadmium wire was folded inside the pit
| during manufacture, and pulled out by a small motor during the
| warhead arming process. Unfortunately, this wire had a tendency
| to become brittle during storage, and break or get stuck during
| arming, which prevented complete removal and rendered the
| warhead a dud. It was estimated that 50-75% of warheads would
| fail. This required a complete rebuild of the W47
| primaries.[7]"_
|
| https://en.wikipedia.org/wiki/W47?useskin=vector#Reliability...
| wl wrote:
| Yeah, looks like boron coated cadmium tape. The relevant
| excerpt from _Command and Control_...
|
| > To avoid the embarrassment of relying on a Los Alamos
| design, Teller used Livermore's new core but added a
| mechanical safing device to it. A strip of cadmium tape
| coated with boron was placed in the center of the core.
| Cadmium and boron absorb neutrons, and the presence of the
| tape would stop a chain reaction, making a nuclear detonation
| impossible. During the warhead's arming sequence, the tape
| would be pulled out by a little motor before the core
| imploded. It seemed like a clever solution to the one-point
| safety problem--until a routine examination of the warheads
| in 1963 found that the tape corroded inside the cores. When
| the tape corroded, it got stuck. And the little motor didn't
| have enough torque to pull the tape out. Livermore's
| mechanical safing device had made the warheads too safe. A
| former director of the Navy's Strategic Systems Project
| Office Reentry Body Coordinating Committee explained the
| problem: there was "almost zero confidence that the warhead
| would work as intended." A large proportion of W-47 warheads,
| perhaps 75 percent or more, wouldn't detonate after being
| launched. The Polaris submarine, the weapon system that
| McNamara and Kennedy considered the cornerstone of the
| American arsenal, the ultimate deterrent, the guarantor of
| nuclear retaliation and controlled escalation and assured
| destruction, was full of duds. For the next four years,
| Livermore tried to fix the safety mechanism of the W-47,
| without success. The Navy was furious, and all the warheads
| had to be replaced. The new cores were inherently one-point
| safe.
| jabl wrote:
| > the military, which wants the weapons to detonate on time
| every time
|
| Well, the military sure is also concerned about avoiding non-
| intentional detonations due to accidents or by being hit by
| enemy fire. E.g. the IMX series of explosives that have
| apparently started to replace TNT and Comp B in some
| applications.
|
| https://en.wikipedia.org/wiki/IMX-101
| KptMarchewa wrote:
| As we've seen in Ukraine, sensitive munitions kill a lot of
| tank, IFV and artillery crews.
| bell-cot wrote:
| You might want to read a bit about the design of WWII-era
| conventional bombs, or WWI-era artillery shells, or magazines
| in sailing ships, or ...
|
| Militaries that have wanted to _win_ (vs. blow themselves up)
| have been laboriously working to make sure that explosives do
| not explode when they shouldn 't for _centuries_.
| TylerE wrote:
| They're pretty good at it, too.
|
| You can set RDX (the explosive in C-4) on fire, and it'll
| burn, not explode. Even small arms fire won't trigger it.
| Kon-Peki wrote:
| If such a thing can be scaled and made reliable, the implications
| are staggering.
|
| Imagine ammunition that fits in existing firearms and is fully
| self-contained, mixing into a viable round only when entering the
| chamber. And then made "smart", such that it can be geofenced and
| therefore refuse to mix near schools or stadiums or government
| buildings, etc.
|
| If this becomes _possible_ , then all traditional ammunition may
| become legislated or litigated out of existence.
| runnerup wrote:
| Ammo is really really safe as it is. Ammo doesn't accidentally
| go off. The modifications you're talking about would go on the
| gun, not the ammo.
| mrguyorama wrote:
| That "gun digitally safed" concept was tried before and
| pretty roundly rejected. Even electrically ignited primers
| were a market failure. Gun people are more paranoid than even
| InfoSec researchers when it comes to tech in their toys. If
| you truly believe your guns are for self defense, it makes a
| little more sense.
| xoxxala wrote:
| Forgotten Weapons on YouTube has a video on the Armatix iP1
| "smart" pistol, the technology behind it, it's development
| and why it was a commercial failure.
| GravitasFailure wrote:
| I haven't heard of any electrically ignited primers that
| made it to market, but every attempt that's gone through
| military trials have had abysmal reliability.
| gao8a wrote:
| See Remington EtronX
| https://www.youtube.com/watch?v=8qP6Q9ZEsEo (but it
| obviously was a commercial failure)
| GravitasFailure wrote:
| Interesting. I missed that one.
| ThrowawayR2 wrote:
| It's a little surprising to see all these replies with none of
| them mentioning that this discovery applies to high explosives,
| which aren't used in small arms ammunition. Ammunition uses
| propellants, which burn quickly (deflagration) but not as
| quickly as high explosives (detonation); the latter would burst
| the firearm. Therefore this discovery is unlikely to have any
| relevance to small arms ammunition.
| sidewndr46 wrote:
| There was at one point some research done on seeing if
| artillery could replace propellants with high explosive. From
| what I understand it concluded that is was completely
| impractical.
| LawTalkingGuy wrote:
| Liquid propellant could be useful in varying the amount used
| per shot. In some large guns (ship guns mainly) you put bags of
| propellant in the gun and you're limited to whole bags. If you
| need a half bag you have to vary your aim to get the desired
| target. It sounds very difficult but might be worth it for
| space savings and for not having explosive ammo laying around.
|
| As for making guns stop working in certain places, why wouldn't
| crime just target those places? My walk home passes malls, a
| school, government buildings, and two stadiums. Why would I
| accept a defensive tool that didn't work most of the time?
|
| If we make gun ownership too onerous we risk people ignoring
| the law altogether - after all the risk of being injured is
| more serious than being caught defending yourself - which would
| increase the black market and aid criminals.
| vkou wrote:
| 1. Why would you install all this into the ammo, rather than
| the gun? Any mechanically-inclined idiot with a garage workshop
| can make his own ammo.
|
| 2. Guns are a political problem, not a technological problem.
| If you want to reduce gun violence, ban handguns. If you want
| to reduce mass shootings, ban handguns and semi-automatic long
| guns. If you want to stop a dedicated idiot with a garage
| workshop from building his own pipe shotgun that he will use to
| execute an MLM cult leader, you can't, he's going to do that
| regardless.
| idiotsecant wrote:
| I'm not sure banning semi-automatic weapons is an effective
| way to stop mass shootings. California has one of the most
| restrictive semi-automatic weapon bans in the country and it
| has one of the higher rates of mass shootings. That seems to
| be pretty good evidence that this policy is restricting
| people who care about the law from possessing these weapons
| and not the people actually committing the crimes.
| vkou wrote:
| California's surrounded by 49 other states, most of which
| have no such restrictions, and does not have any border
| controls with any of them.
|
| The formula of access changes substantially when you don't
| have opportunities for jurisdictional arbitrage.
|
| Criminals don't sit in a pentagram and magick weapons up
| out of thin air, they source them (legally and otherwise)
| from legitimate owners. A few of them are also legitimate
| owners, who choose to use them for crime.
| TylerE wrote:
| If you really want to do something good, don't ban semi-
| autos, or long guns at all.
|
| Make it way harder to get a pistol. That's what's used in
| the vast majority of murders.
|
| Those two mass shootings in California earlier this year?
| Both pistols.
|
| I also think that concealed carry should generally be
| banned for most civilians, and open carry legal.
|
| My views on guns tend to generally annoy both sides...
| RajT88 wrote:
| I won't go so far as to say I'm on your side, but it's a
| valid way of looking at the issue. It's the statistical
| approach - target the biggest part of the problem.
|
| IIRC handguns are used in 75% of firearm deaths from all
| causes (homicide, suicide, accidents).
| nullc wrote:
| > IIRC handguns are used in 75% of firearm deaths from
| all causes (homicide, suicide, accidents).
|
| kind of a distorted figure there because suicide
| dominates by a wide margin, and gun availablity doesn't
| change the suicide rate. e.g. when controlling for
| latitude you get similar suicide rates in places without
| guns, people just use different means.
| throwanem wrote:
| That would require a battery, a GPS chipset, and either a
| sizable database or a cellular radio, in the base of every
| cartridge.
|
| I'm pretty sure ammo makers aren't shaking in their boots on
| this one.
| TylerE wrote:
| You could probably do it with something like Bluetooth LE in
| the bullet. You'd need some sort of base station, worn on a
| belt loop or something.
|
| Binary explosives certainly exist so it should be in theory
| possible. Not sure how well they "scale down" though, and I
| don't know if any have a blast velocity low enough to be
| workable. I'm not a gun guy, really, outside of my interest
| in naval warfare. 16" shells have slightly different design
| params though.
|
| Actually, thinking about it more would the barrel act like a
| faraday cage?
| A4ET8a8uTh0 wrote:
| Loved the read. I know I am on a list somewhere now, but I don't
| care. This is what HN is all about. Interesting knowledge.
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