Proteus Technology: New Material Is Strong, Light and Non-Cuttable(scitechdaily.com)
scitechdaily.com
Proteus Technology: New Material Is Strong, Light and Non-Cuttable
https://scitechdaily.com/proteus-technology-new-material-is-strong-light-and-non-cuttable/
248 comments
This resists mechanical forces, but what about EDM milling or plasma ?
Link to scientific paper: https://www.nature.com/articles/s41598-020-65976-0
Waiting for this to exist in an Abus lock so my storage unit can stop being broken into my tweakers.
It only protects you from tweakers armed with cutters. Industrious tweakers with better tools at their disposal might be able to crush it or melt it.
Like, say, a Hytek 6000W fiber laser cutter?
At least it eliminates the majority from contention.
>industrious tweakers with better tools
They're probably breaking in hoping to steal tools to sell. If they had decent tools they would have already sold them. It's not impossible but well-equipped tweakers are far less likely than other kinds of thief.
On the other hand they're batshit crazy enough to try other means, why bother trying to break into a storage unit when you can chain the door handle to your (also stolen) car and rip the whole unit door off.
They're probably breaking in hoping to steal tools to sell. If they had decent tools they would have already sold them. It's not impossible but well-equipped tweakers are far less likely than other kinds of thief.
On the other hand they're batshit crazy enough to try other means, why bother trying to break into a storage unit when you can chain the door handle to your (also stolen) car and rip the whole unit door off.
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If it has a keyhole it can be picked, a lock made of diamond wouldn't resist.
> If it has a keyhole it can be picked
What if you can't get your picks into the keyhole?
I saw a lock that had a tubular key, and an airlock-like mechanism between the place the actual keyhole and the opening for you to insert the key. You would insert the key, and then activate the airlock-like mechanism which would transport the key to the keyhole.
There was then a mechanism to rotate the thing that was holding the key so as to unlock the lock.
The actual keyhole in this lock was never exposed to the outside.
What if you can't get your picks into the keyhole?
I saw a lock that had a tubular key, and an airlock-like mechanism between the place the actual keyhole and the opening for you to insert the key. You would insert the key, and then activate the airlock-like mechanism which would transport the key to the keyhole.
There was then a mechanism to rotate the thing that was holding the key so as to unlock the lock.
The actual keyhole in this lock was never exposed to the outside.
Bosnianbill's YouTube channel has featured some nifty "unpickable" designs:
* Inaccessible keyhole: https://invidio.us/watch?v=OLsJDELd4lo
Sounds related to the lock you describe, except this one is purely mechanical.
* Serpentine keyhole: https://invidio.us/watch?v=1ey2SFHbZV8
* Inaccessible keyhole: https://invidio.us/watch?v=OLsJDELd4lo
Sounds related to the lock you describe, except this one is purely mechanical.
* Serpentine keyhole: https://invidio.us/watch?v=1ey2SFHbZV8
Will this work as armor?
I believe that answer hinges on whether "cut proof" is the same as "puncture-proof".
Sword players will still be interested...
Not really. Armor made of this material has to be much thicker than ordinary steel plate. Furthermore, ordinary steel plate is entirely effective against swords, except at the joints and articulations.
> entirely effective against swords
Against the immediate cutting, probably. But it also bends. And with bending, it could damage you really bad, including the part that removing them could become quite a trouble.
Against the immediate cutting, probably. But it also bends. And with bending, it could damage you really bad, including the part that removing them could become quite a trouble.
True, but cutting is what we're talking about here, and since the material they've invented in this article is made of aluminum foam, it'll bend even easier than steel of the same thickness.
If your attacker is wielding a grinder or a drill, and you don't mind wearing a 2-inch-thick metal plate, then sure.
Porous Aluminum eh? Wonder how well it stands up to gallium, or acetylene, or MAP gas, or a grind wheel instead of a cutoff wheel.
the ceramic inside is alumina, so same material as both a cutoff wheel and a grinding wheel. They mention that it's not the best purity and hardness, but it's pretty good.
This non-cuttable metal material sounds extremely useful:
> "Security applications such as doors or barriers (as protection from forcible entry attacks) are obvious ones. However, our material technology could also be useful for enhancing the cutting resistance of shoe soles or protective clothing. Workers could benefit from non-cuttable elbow pads or forearm guards in environments with industrial tools."
As someone who cares so much about digital security, physical security feels good.
> "Security applications such as doors or barriers (as protection from forcible entry attacks) are obvious ones. However, our material technology could also be useful for enhancing the cutting resistance of shoe soles or protective clothing. Workers could benefit from non-cuttable elbow pads or forearm guards in environments with industrial tools."
As someone who cares so much about digital security, physical security feels good.
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This material is completely unsuited for making shoe soles or elbow pads; it's a two-inch-thick plate of aluminum foam with half-inch ceramic spheres embedded in it. Around that they welded steel plates to give it a uniform surface.
It'd make a very heavy but uncuttable door, but you can't make hinges or locks out of it. It would be a good material to make safes out of; those already have thick walls of composite materials designed to blunt drill bits.
It'd make a very heavy but uncuttable door, but you can't make hinges or locks out of it. It would be a good material to make safes out of; those already have thick walls of composite materials designed to blunt drill bits.
I think that's a premature judgement.
Is there any reason to think that it's impossible to scale it down? e.g. for PPE, 5mm ceramic spheres in a 1cm-thick Aluminimum foam with some 1mm steel plates on either side?
Is there any reason to think that it's impossible to scale it down? e.g. for PPE, 5mm ceramic spheres in a 1cm-thick Aluminimum foam with some 1mm steel plates on either side?
Yes, there is. They hypothesize that this material works because the ceramic spheres vibrate inside the flexible matrix of the aluminum foam, damaging the grinding wheel. A thinner foam will have less ability to flex, and smaller spheres will be have less momentum to use against the wheel.
Plus, if you watch the video of them grinding the material (https://static-content.springer.com/esm/art%3A10.1038%2Fs415...), you can see that the grinding wheel penetrates over half an inch before it begins to be destroyed.
Plus, if you watch the video of them grinding the material (https://static-content.springer.com/esm/art%3A10.1038%2Fs415...), you can see that the grinding wheel penetrates over half an inch before it begins to be destroyed.
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For comparison I was learning about medieval armor recently. Steel breastplates are about 2mm at their thickest, typically. So that's a rather heavy duty armor idea you have.
Real question then is how it would fare against bullets and piercing attacks. Cutting is only one possible threat, and usually not the biggest threat. Knife resistant bullet proof vest are already a thing, so how would this be better?
Real question then is how it would fare against bullets and piercing attacks. Cutting is only one possible threat, and usually not the biggest threat. Knife resistant bullet proof vest are already a thing, so how would this be better?
If you make a secure doorway with the hinges on the threat side, well, you're already toast. No need to make hinges out of anything special.
I want a bike lock made of this stuff
I'm sure lockpickinglawyer will still open it just fine.
Yeah but 99% of thieves can't do that. If they could then they'd likely have a real job. Lots of locks are invulnerable to the picking, especially serious digital ones.
They just use a Ramset gun. Thieves are generally quite smart. The dumb ones tend to end up in prison, or worse.
I’ve watched a bunch of lockpickinglawyer videos and there are locks he cannot pick at all, and locks which take a hell of a lot of punishment from a Ramset gun. It’s not out of the realm of possibility that you could build a bike lock which would effectively deter thieves. After all, it doesn’t have to be indestructible, it just has to convince the thief that your bike is not worth the time and risk of attracting attention.
One painful lesson I learned after having an expensive bike with an expensive lock stolen is that as you harden the lock at some point the weakest link shifts from being the lock to the thing the lock is attached to.
You didn't attach it to another lock?
Some bike racks are designed to maximize capacity, and you're supposed to roll your front wheel into the rack, between some very narrow vertical bars. You could probably cut the bars with any decent bolt cutter, and certainly with a hacksaw. The U shapes and up-and-down S shapes, where you can move your bike alongside a thick element and lock the frame, are fundamentally better but will still be cuttable.
I've seen thieves cut street signs and sturdy bike racks to take a bike. I don't really see this material working for relatively thin bars like a regular U-lock. The base material is aluminum which is relatively soft. Thieves would just switch to shearing action tools to cut through it and if the bar isn't very thick they'd probably only encounter 1 or 2 of the ceramic beads and push them away through the soft metal. They might even use a portable torch to soften it up before cutting.
Conceivably you could have a thick Proteus core with a thick hardened steel casing but it makes the lock either unwieldy or terribly expensive. Maybe they will be able to embed the ceramic beads directly in hardened steel, making it lighter and more resistant to cutting.
Conceivably you could have a thick Proteus core with a thick hardened steel casing but it makes the lock either unwieldy or terribly expensive. Maybe they will be able to embed the ceramic beads directly in hardened steel, making it lighter and more resistant to cutting.
Get some brightly coloured spray-paint. Neon pink, gold or whatever. Paint the whole bike with it, obviously try not to get it in the mechanically sensitive parts but otherwise coat the whole thing. No-one is going to steal that, it will still ride just as well.
This is a little disingenuous. There exist locks that he cannot pick, but the vast majority of his uploads are three minutes or fewer and include a successful picking attempt. More on-topic for this thread, a common LPL theme is that bike lock chains are made of high-quality hard-to-cut material, but the lock cores are still often commodity parts which are picked open by standard techniques and tools.
I would say that much more important for discussing LPL is that he has immense real-world experience, equivalent to a master locksmith, and he builds his own picks. I am not the best lockpicker, but I bet that even I could open bike locks as quickly as he does, if only I had "the tool that [he] and BosnianBill made" in my fingers. Indeed, the community has talked quite a bit about the tool, and perhaps we'll get a 2020 gift in either a commercially-available version or public specifications for building them at home [0].
[0] https://old.reddit.com/r/lockpicking/comments/atf3ef/so_that...
I would say that much more important for discussing LPL is that he has immense real-world experience, equivalent to a master locksmith, and he builds his own picks. I am not the best lockpicker, but I bet that even I could open bike locks as quickly as he does, if only I had "the tool that [he] and BosnianBill made" in my fingers. Indeed, the community has talked quite a bit about the tool, and perhaps we'll get a 2020 gift in either a commercially-available version or public specifications for building them at home [0].
[0] https://old.reddit.com/r/lockpicking/comments/atf3ef/so_that...
Ride something from the early 80s, before they went to neon colors.
I am highly entertained by this, because I just happened to find his videos a few weeks ago and have been watching a ton of them.
Since it uses an aluminum matrix, abrasive cutting may not work, but plasma or gas cutting certainly will. A propane tank and a torch aren’t too difficult to get if someone knew they would need them.
"Digital security" is now how I will refer to safety boots and gloves.
So how do you shape/use it during manufacturing?
Heat? Chemistry?
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> ... hardness may not be a fundamental property of a material but rather a composite one including yield strength, work hardening, true tensile strength, modulus of elasticity, and micro properties such as strength of atomic bonds.
Now that is pretty interesting.
It seems they tuned the material to resist the angle grinder, drill and water jet but it would be interesting to see its ballistic resistance.
Now that is pretty interesting.
It seems they tuned the material to resist the angle grinder, drill and water jet but it would be interesting to see its ballistic resistance.
I'm not sure why anyone would want cut resistant shoe soles, but I know lots and lots of people who want puncture resistant shoe soles. Isn't that a similar process to ballistics?
I note that they didn't really cover that territory, and wonder if that was lack of facilities or avoiding the tough questions.
I note that they didn't really cover that territory, and wonder if that was lack of facilities or avoiding the tough questions.
> Isn't [puncture] a similar process to ballistics?
Maybe in a sense, but I think not really. Bullet-proof vests aren't necessarily (usually?) stab proof. (And vice-versa of course.)
Maybe in a sense, but I think not really. Bullet-proof vests aren't necessarily (usually?) stab proof. (And vice-versa of course.)
Wonder what a blow torch or other commonly available chemical agents would do to it.
My first thought was "New bike lock material"
My second was:
"New non-cuttable bike lock defeated by ______"
{freezing, shock, heat, _ }
My second was:
"New non-cuttable bike lock defeated by ______"
{freezing, shock, heat, _ }
Defeated by small hydraulic jack
acid to disolve the aluminium in the structure
If you wanted to go the chemical route, galium would do it.
Yeah, I wanna see what happens when you thump it with a hammer.
This says nothing about the momentum of the cutting tool. My immediate instinct is: "New non-cuttable bike lock defeated by - Cable Cutters - "
Great engineering regardless, would love to work on a project like this.
Great engineering regardless, would love to work on a project like this.
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"... a tool bosnianbill and I made."
Ramset.
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How about a plasma cutter? I know a plasma cutter will cut through normal silica. (I cut through some steel plate laying right on top of large gravel.) Silicon dioxides melting point is 1700 C, and aluminum oxide is 2100 C, a little higher.
Isn't a plasma cutter actually melting an area out of a material and not actually cutting it?
It does both!
My point is that if you look at that definition of "cut", it's not just rendering one item into two pieces, other wise tearing or cracking something would be cutting it, and those aren't cutting either.
I doubt this material is impervious to shear force, or being lowered in temperature until it's brittle and cracked. But those aren't methods of cutting.
I doubt this material is impervious to shear force, or being lowered in temperature until it's brittle and cracked. But those aren't methods of cutting.
I mean, this material is only resistant to drilling and grinding. Saying you "cut" something with an angle grinder is a fair use of the term, yet grinding away at something probably isn't the first thought people have when you just say "cut". I'd say the truest form of cutting is shearing, as with shears.
I don't see the distinction. Everything but shears removes material at the cut. A plasma cut is no different in that respect from a saw, grinder, water-jet, laser, torch.
Cutting something with scissors, or in the case of thicker metal a press with a bit, doesn't remove material. Tearing something in two doesn't remove material. But you're right, any sawing type cut, as with a grinder, does remove material.
What I was really getting at though is that if you look at the definition of "cut" you'll see in most (all?) sources it defines it has being achieved through a sharp object or tool. I understand that's not often how it's used colloquially though.
What I was really getting at though is that if you look at the definition of "cut" you'll see in most (all?) sources it defines it has being achieved through a sharp object or tool. I understand that's not often how it's used colloquially though.
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This would be great for bike locks!
I'd bet against it. It seems to hold up well against abrasive tools, but an aluminum foam with ceramic balls embedded in it doesn't sound like the recipe for an all around robust lock shackle. How would it stand up against bolt cutters (shearing cuts, not abrasive cutting), a manually operated hacksaw, or impact? A hacksaw might have the finesse to thread the gap between the ceramic.
My guess is that the hacksaw wouldn't work particularly well, but the bolt cutters or anything else that just exerts a strong, steady force without much motion should work. At that point, it shouldn't be any stronger than just regular aluminium.
This could be a revolution in bike locks. Right now compact battery powered cutting tools can remove just about any bike lock quickly and can easily be concealed.
This is an absolutely amazing innovation, but bike thieves have already progressed to using powder-actuated pistons in order to break the internal mechanism of a lock. Much faster and easier than cutting anything.
In any major city really the solution is to never lock anything up in public that is worth more than $400 or so. I have two road bikes, the insurance replacement value of each would probably be $3000, and I wouldn't even dream of buying a lock. I literally don't even know where my lock is. The last time I saw a lock was when I put it in a box of stuff on a shelf in my garage 10+ years ago.
If you have a nice road bike with very clean tires people generally will not mind you bringing it into places with you consistently.
No matter how good your lock is, if somebody REALLY wants the bike (for the value of its components) they'll just saw the frame in half.
If you have a nice road bike with very clean tires people generally will not mind you bringing it into places with you consistently.
No matter how good your lock is, if somebody REALLY wants the bike (for the value of its components) they'll just saw the frame in half.
We definitely mind, we're just too polite to tell you. Knowing your friend spends thousands (plural) on their bike makes you feel bad about not wanting their "clean" tires, which definitely didn't roll through dog turds and cat pee on the way there, on your floors.
To clarify I did not mean taking a bike into peoples' houses, but commercial establishments that already see a high volume of foot traffic. The tread pattern and grip on any shoes collects far more feces and other dirt from sidewalks than a smooth treadless 700x23 tire.
On the plus side, multi-thousand-dollar bikes can be lifted with one hand and slung over your shoulder if you're a courteous rider.
Not most e-bikes. They're heavier than normal bikes. I just use multiple heavy-duty locks, through the frame and both wheels.
Yeah an ebike can be considerably more heavy. What I had in mind for my description was something like a full carbon road frame and fork, Shimano 105 current generation components or the sram equivalent, and a good quality lightweight wheelset.
yeah I definitely don't ride my bike through dog turds, and if I did you'd find evidence on my shoes before my tires (from which it would have already been rubbed off)
Not sure I follow, I take it by implication you have renter's or homeowner's insurance, in which case your replacement cost is the deductible - and $400 is a common deductible. Now, getting a bike set up the way you had yours is a pain, granted. I think it's pretty unlikely that even desperate thieves would saw through your frame, they want to be able to resell as much of the bike as they can, and the frame is a fairly valuable component...
I've managed to keep my bike locked up outside OVERNIGHT in San Francisco (Washington & Polk St.) for a year now. How I did it? The short version: one very good lock (Viro Euromonolith + Peewag security chain, $175), a second good lock (kryptonite, $90), and an okay lock (Abus, to keep them from stealing the basket, $60).
I've also had 3 bikes stolen, the rear wheel stolen, the basket stolen, the front brake stolen, the seat stolen, but now with all the locks there is much less stealing.
I've also had 3 bikes stolen, the rear wheel stolen, the basket stolen, the front brake stolen, the seat stolen, but now with all the locks there is much less stealing.
Geez, they stole your front brake? What the hell are they going to do with it?
What is the cost of it? A few bucks? I can’t even be bothered to sell my used crap on eBay.
What is the cost of it? A few bucks? I can’t even be bothered to sell my used crap on eBay.
A stolen front v brake / rim brake? They're going to trade it along with a few other choice bike parts they've collected for $15 worth of meth, crack or synthetic opiates.
If I may ask, what is the specification/purchase value of the bike? Is it cheap enough to not look like a juicy target?
The bike was around $700-$800 new (I bought it used for $500). It's a Public bike, and their closest current model is the PUBLIC M7i, which retails for $799.
It's a target, but it's certainly not a "juicy" target like, say, a $3k mountain bike.
The bike thieves continue to steal the small stuff, notably the rubber attachments which hold my bike lights, but haven't been able to steal the big stuff (frame, wheels, basket, seat) in a long time.
One of the strangest things that was stolen is the yellow electrician's tape I used to "dog" my seat with—they painstakingly peeled off the tape, but left the seat.
It's a target, but it's certainly not a "juicy" target like, say, a $3k mountain bike.
The bike thieves continue to steal the small stuff, notably the rubber attachments which hold my bike lights, but haven't been able to steal the big stuff (frame, wheels, basket, seat) in a long time.
One of the strangest things that was stolen is the yellow electrician's tape I used to "dog" my seat with—they painstakingly peeled off the tape, but left the seat.
How does that work?
Essentially, the powder actuated piston fires a blank round and uses the pressure in order to propel a mass, that hits the lock and, assuming that the lock is restrained in the opposite direction, creates an immense force that destroys the internals of the lock and forces it open, all in less than a second.
Is this sort of like the weapon the guy in No Country For Old Men was using?
That's a captive bolt gun. It's used to kill cattle for slaughter.
I don't remember the movie well enough, but it might have been a captive bolt gun (typically used for slaughtering livestock)?
Doesn't that use compressed air?
The one shown in that movie uses compressed air. Some other sorts use powder charges, just like a powder actuated nailgun.
Pneumatic
Maybe in YouTube videos but I have not heard of people using Ramsets to steal bike in real life. Firing a gun is a good way to get people call the cops.
Edit: I am wrong!
Edit: I am wrong!
The new Ramset guns are surprisingly quiet. Certainly, the police won't be called, and there's not much of a risk to the thief.
This is because unlike a gun, there is no need for the gases to release to the outside openly. Therefore, there is much, much less noise, and it doesn't sound like a gun at all.
This is because unlike a gun, there is no need for the gases to release to the outside openly. Therefore, there is much, much less noise, and it doesn't sound like a gun at all.
I wonder if the battery-powered propellant-free Hilti fastener shooter would work, those things are extremely quiet!
It's my understanding that the actual propulsion of a nail is no more powerful than a powder actuated tool, which use cartridges similar in power to the very small .22LR
Do you have lots of experience looking at reports of stolen bikes? I have heard exactly the opposite in my major metro area. My sources are law enforcement and bike clubs.
Nobody will stop you in San Francisco.
Not to mention pre-cutting bike racks themselves (and handrails, etc. that people lock their bikes to), and then putting some duct tape or something over the cut. When they get ready to take your bike they don't have to cut a thing. Just lift up the cut section, slip your chain/lock through the gap, and go.
Even without a pre-cut rack, its pretty common that whatever you've locked up to (sign post, bike rack, parking meter, handrail, etc) is a lower grade of steel than the ultra-hard stuff on the shackle of a good bike lock or chain anyways. No need to pre-cut that cheap galvanized steel sign post if you don't want to, a thief would have no problem getting through it quickly if something attractive was locked up.
I'll use about $100 worth of u-locks to lock up my not-super-visually-impressive $250 spare parts city errand bike as long as overnight (and this is in NYC).
But I think the strike point where spending more on heavier/fancier locks to secure a more valuable bike just stops making sense is right about at the price point I'm already at, most nicer bikes are simply too nice to leave unattended on city streets in the US or anywhere else where bike theft is a concern. Someone with a good set of pocket tools could rip $500 worth of parts off a well-locked frameset and wheels in 20 mins without making any noise... and I don't think a non-cuttable material helps that scenario, even if it does make very secure locks attainability light.
(Could be a really big deal for bike touring folks though, who often ride out with a cheap cable lock at best because anything better is too heavy to carry for days/weeks)
I'll use about $100 worth of u-locks to lock up my not-super-visually-impressive $250 spare parts city errand bike as long as overnight (and this is in NYC).
But I think the strike point where spending more on heavier/fancier locks to secure a more valuable bike just stops making sense is right about at the price point I'm already at, most nicer bikes are simply too nice to leave unattended on city streets in the US or anywhere else where bike theft is a concern. Someone with a good set of pocket tools could rip $500 worth of parts off a well-locked frameset and wheels in 20 mins without making any noise... and I don't think a non-cuttable material helps that scenario, even if it does make very secure locks attainability light.
(Could be a really big deal for bike touring folks though, who often ride out with a cheap cable lock at best because anything better is too heavy to carry for days/weeks)
> its pretty common that whatever you've locked up to (sign post, bike rack, parking meter, handrail, etc) is a lower grade of steel than the ultra-hard stuff on the shackle
Way back in highschool this always used to baffle me. You'd get kids spending $50+ on super fancy locks for their lockers, but all these locks equally were fastened to the locker with a flimsy little hasp that you could cut with a pair of tin snips, assuming you didn't just bend back the door of the locker itself.
Way back in highschool this always used to baffle me. You'd get kids spending $50+ on super fancy locks for their lockers, but all these locks equally were fastened to the locker with a flimsy little hasp that you could cut with a pair of tin snips, assuming you didn't just bend back the door of the locker itself.
Often, and notably in the case of school lockers, there is a huge difference in bypassing a lock using a method that leaves traces of your passage and using a method that renders your infraction undetectable - or at least undetected.
That's brilliant. It reminds me of people who have written about how disappointing magic tricks generally are when they're revealed, because you think "I could have thought of that" but you probably couldn't.
Locks should have a layer of explosive material inside, so firing the powder-actuated tool (PAT) may ignite the explosives and destroy the PAT itself, and it would help too by making some very strong noise so people may hear something is going on.
Are you going to make that explosive sensitive to shocks? Otherwise, how is it going to ignite? And if you would do so, you realize how dangerous that is, right?
Booby traps are illegal.
You can do whatever you want with your bike but I sure am not carrying something designed to be activated by a strong jolt on my bike when I bike through decaying city streets full of potholes and bumps and other fun stuff like that.
I’m sure the legal department of the lock manufacturer would recommend against that..
I hope this thread results in an FP post about this, because I am super curious now and there's only tidbits here ("engine pistons?" "what's a ramset?").
Prison cells (whose rooms are cast concrete over rebar). AT machines. Vaults, safes... Lots of things. Roll-up shutter doors... fences around construction equipment.
Not enough people are tunnelling their way out of prisons to justify the expense of building prisons out of anything like this. And it's too bulky for shutters or fences.
Safes and vaults might be a good application.
Safes and vaults might be a good application.
> Not enough people are tunnelling their way out of prison
If i am ever in jail i am going to correct this issue
If i am ever in jail i am going to correct this issue
Jail and prison are not the same thing. Jail is for light crimes - most people in jail leave every day to go to work, and then return to jail when work is over. It is easy to run, but odds are they will catch you (they know your family, job and friends...). It isn't uncommon for the windows to open without triggering even an alarm.
Prison is a level higher. You start out in a more secure setting where it is harder to do anything without getting caught. (if you only get 1cm of tunnel built it doesn't do you any good). If they suspect you are going to pull anything they move you to more secure prisons where you are watched closer.
You might be smart, but there have been lots of smart people in prison before you with nothing better to do than dream up every possible escape plan. They are gotten good at detecting and preventing them over the years. In short odds are against you getting out successfully, and the attempt will earn you more time in prison.
Prison is a level higher. You start out in a more secure setting where it is harder to do anything without getting caught. (if you only get 1cm of tunnel built it doesn't do you any good). If they suspect you are going to pull anything they move you to more secure prisons where you are watched closer.
You might be smart, but there have been lots of smart people in prison before you with nothing better to do than dream up every possible escape plan. They are gotten good at detecting and preventing them over the years. In short odds are against you getting out successfully, and the attempt will earn you more time in prison.
It's a joke.
I don't claim to be especially smart, and even if i were it does not neccesarily translate to 'succes in prison' or tunneling skills.
I don't claim to be especially smart, and even if i were it does not neccesarily translate to 'succes in prison' or tunneling skills.
What construction equipment could possibly need an indestructible fence surrounding it?? Most construction sites have chain link or orange plastic fences, and they’re not to prevent theft. You hire security or insure the equipment against theft to protect against theft.
Anyone that owns heavy equipment carries insurance covering damage, theft, and liability. Otherwise it’s rented and Sunbelt or whoever is on the hook to replace it.
Safe and vaults, sure.
Anyone that owns heavy equipment carries insurance covering damage, theft, and liability. Otherwise it’s rented and Sunbelt or whoever is on the hook to replace it.
Safe and vaults, sure.
The fence is to keep 5 year olds out. As the parent of a 5 year old I'm not sure this is strong enough to do the job.
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Looking at the paper, the material is 13mm ceramic spheres (about the width of a finger) suspended in a foam of aluminium and a small amount of titanium. The bike lock would have to be quite thick, particularly the armour around the locking mechanism.
Forget locks... just make my tires out of this.
Punctured tyres are not a problem in practice anymore. Puncture resistant tyres are fairly cheap and very reliable. I cycled thousands of kilometers without getting a flat.
They are very much a problem still, I've punctured a tire recently (the expansive puncture-resistant one). That's after several punctures last year (but that was on a regular old tires, that's why I switched). Before you ask - it's not a problem with the wheel or anything, I've had it checked.
I've never had a flat tire in the countryside trips, though. It's always on broken glass some jerks throw at bike lanes in bigger cities.
Also probably the fact I'm overweight is a factor.
BTW when I was about 7 I had a small bike with full-rubber tires. It was great, I wonder why it's not done for full-size bikes. It wasn't THAT much heavier.
I've never had a flat tire in the countryside trips, though. It's always on broken glass some jerks throw at bike lanes in bigger cities.
Also probably the fact I'm overweight is a factor.
BTW when I was about 7 I had a small bike with full-rubber tires. It was great, I wonder why it's not done for full-size bikes. It wasn't THAT much heavier.
I dug several mm long glass shards out of my Schwalbe Marathon+ without them penetrating to the tube, but if you want solid rubber, you can buy it: https://tannus.com/tires/
On cars they absolutely are still a problem in practice.
Why would you want aluminium foam tires?
Very good point. It's not an entirely serious suggestion. I just want tires made out of something indestructible.
watch the video its resistant to grinding and its resistance come from vibrating back at the grinder and for that it requires a hefty thickness, so far there's little indication it would resist at bike lock thickness or against bolt cutters
It's aluminium; it wouldn't stand a chance against a pair of bolt cutters or even a pry bar. It'll have weak tensile strength.
Of course, maybe a core of this stuff with an outer shell of hardened steel.
Of course, maybe a core of this stuff with an outer shell of hardened steel.
I wonder how well it handles cold.
I remember hearing about thieves spraying down those u-lock style locks with refrigerant, then tapping them with a hammer. They would shatter like glass.
I remember hearing about thieves spraying down those u-lock style locks with refrigerant, then tapping them with a hammer. They would shatter like glass.
I wish there were a way to get a sample of this to the lockpickinglawyer.
I was thinking of the Hydraulic Press Channel...
It's odd that the title says "non-cuttable" and the tests they carried out in the article are all attacking it from one side, when most people will think of something like scissors that exert a high compressive force to shear the material.
To me, this material sounds more like it's highly abrasion-resistant than "non-cuttable".
It's odd that the title says "non-cuttable" and the tests they carried out in the article are all attacking it from one side, when most people will think of something like scissors that exert a high compressive force to shear the material.
To me, this material sounds more like it's highly abrasion-resistant than "non-cuttable".
I'm guessing he'd bust out a blowtorch and make short work of it.
Or just pick the (literal weak link in the chain) cheapo lock attached to it. I'm pretty exhausted from listening to people boast about the amazing lock they put in their door, which has full-length windows on both sides. Or their super sturdy door with a generic kwikset lock. The evergreen penetration testing motto is appropriate here: the goal is simply to get on the other side of the door.
Nah, the hydraulic press will make short work of it, the material holding things together is just aluminium after all.
The ceramic balls though, hoo boy. Here's one with a ceramic bearing ball vs a high speed air ram: https://www.youtube.com/watch?v=A6nvM7pYBGc
The ceramic balls though, hoo boy. Here's one with a ceramic bearing ball vs a high speed air ram: https://www.youtube.com/watch?v=A6nvM7pYBGc
Physical shields for spacecraft?
Bullet proof vests?
Ammunition?
Bullet proof vests?
Ammunition?
Motorcycle protective gear.
Combined with an energy dissipating foam it would make for some interesting ballistic armor. Especially at 15% the density of steel.
In Star Trek, they called it transparent aluminium!
That's a real thing: https://en.m.wikipedia.org/wiki/Aluminium_oxynitride
Sounds amazing, but how will we dispose of this? Looks like 760 C is required to form this. I imagine it will need to be heated above this to dispose of.
Huh? Plenty of things go in landfills that won't go away for many lifetimes
That's hardly more than the melting point of aluminum (which is a large part of what this is made with.) It's much less than the melting point of copper, glass, or steel.
> The freefall of grapefruit from 10 m does not damage the pulp[1] because pomelo peel consists of vascular bundles and an open-pored cellular structure with the struts made of parenchymatic cells.
I have a Marsh grapefruit tree, fruiting now (southern hemisphere) as it happens, and I note that it produces particularly pithy progeny. (Ignoring for the moment that Pomelo is one of the parents of the modern grapefruit.)
I don't have a convenient 10 metre drop to test this, and while I have no reason to doubt the veracity of this citation, I'm now consumed with curiosity why this plant has evolved to have this feature.
I expect it's quite an expensive adaptation, and given that modern specimens are the result of a lot of cross-breeding over the years to have juicier pulp and a lower ratio of skin/pith to pulp (ie. reduced resistance to damage) it presumably was even more expensive in ancestor plants.
Standard fruit purpose is to have animals unwittingly propagate the plant -- entice something to eat the fruit, and some time / distance later, deposit the seeds in a fertiliser ball. How does protecting the pulp from these kind of damage assist with that -- unless ancestor trees were spectacularly tall, and ancestor consumers fantastically fastidious on fruit quality.
[1] https://doi.org/10.1088%2F1748-3190%2F11%2F4%2F045002
I have a Marsh grapefruit tree, fruiting now (southern hemisphere) as it happens, and I note that it produces particularly pithy progeny. (Ignoring for the moment that Pomelo is one of the parents of the modern grapefruit.)
I don't have a convenient 10 metre drop to test this, and while I have no reason to doubt the veracity of this citation, I'm now consumed with curiosity why this plant has evolved to have this feature.
I expect it's quite an expensive adaptation, and given that modern specimens are the result of a lot of cross-breeding over the years to have juicier pulp and a lower ratio of skin/pith to pulp (ie. reduced resistance to damage) it presumably was even more expensive in ancestor plants.
Standard fruit purpose is to have animals unwittingly propagate the plant -- entice something to eat the fruit, and some time / distance later, deposit the seeds in a fertiliser ball. How does protecting the pulp from these kind of damage assist with that -- unless ancestor trees were spectacularly tall, and ancestor consumers fantastically fastidious on fruit quality.
[1] https://doi.org/10.1088%2F1748-3190%2F11%2F4%2F045002
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> produces particularly pithy progeny
> fantastically fastidious on fruit quality
Great alliterations. Great writing all around. This just made my night.
> fantastically fastidious on fruit quality
Great alliterations. Great writing all around. This just made my night.
I'm always amazed by the Anglo-Saxon attraction for alliterations :-)
Amazing alliterations always achieve admiration.
Asonance also allows adulation.
Wow didn't realize it till you pointed out. It's like I just had a Princess Caroline moment watching Bojack Horseman
Don't miss proPagate the plant!
Seconded. This could have been written by Churchill.
Actual Churchill quote would be "My dear you are inedibly bitter, but tomorrow I shall be sober and you will still be inedibly bitter."
Not Churchill, alas. https://quoteinvestigator.com/2020/06/28/drunk/
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I have a 5-6m high grapefruit tree, and they... do not survive the fall. This material sounds cool but I hope it's better than my grapefruit.
Pomelo has a bit of a different ratio of rind to fruit than most grapefruit.
https://en.wikipedia.org/wiki/Pomelo#/media/File:Citrus_gran...
https://en.wikipedia.org/wiki/Pomelo#/media/File:Citrus_gran...
> This material sounds cool but I hope it's better than my grapefruit.
Flavor-wise it undoubtedly is.
Flavor-wise it undoubtedly is.
While researching a reply, I uncovered USDA Technical Bulletin No. 1413: "Thermal Properties and Heat Transfer Characteristics of Marsh Grapefruit". Please enjoy:
https://hortscans.ces.ncsu.edu/uploads/t/h/thermal__51bf44b0...
https://hortscans.ces.ncsu.edu/uploads/t/h/thermal__51bf44b0...
Goodness, that is interesting.
It's not clear why this matters from the paper, in that it sounds like (but not spelled out) that they are perhaps trying to refrigerate fruit for transport, where the transport itself is not actively refrigerated, merely insulated, so the reduction to target temperature has to occur before shipping. However this was published in 1970, and I'd assume in that part of the world refrigerated shipping and (large) storage was not uncommon?
Aside #1 - undamaged grapefruit will happily store at room temperature for 6 weeks or more, and be the tastier for it.
Aside #2 - received wisdom is that grapefruit, and perhaps most citrus, benefit from one or more frosts to 'sweeten up', though I have never understood the mechanisms for this claim, or how high-water fruit does not burst its vesicles and then deteriorate rapidly.
TFA and this paper you cited may speak to the latter (the fruit content does not freeze overnight as the thermal inertia is so high), and might partially debunk the former.
It's not clear why this matters from the paper, in that it sounds like (but not spelled out) that they are perhaps trying to refrigerate fruit for transport, where the transport itself is not actively refrigerated, merely insulated, so the reduction to target temperature has to occur before shipping. However this was published in 1970, and I'd assume in that part of the world refrigerated shipping and (large) storage was not uncommon?
Aside #1 - undamaged grapefruit will happily store at room temperature for 6 weeks or more, and be the tastier for it.
Aside #2 - received wisdom is that grapefruit, and perhaps most citrus, benefit from one or more frosts to 'sweeten up', though I have never understood the mechanisms for this claim, or how high-water fruit does not burst its vesicles and then deteriorate rapidly.
TFA and this paper you cited may speak to the latter (the fruit content does not freeze overnight as the thermal inertia is so high), and might partially debunk the former.
(absorbed by osmosis during my time at Zest, a JIT produce handling company)
Harvest time is extremely hectic. There's a very small window to get months worth of produce picked, sorted, cooled, packed and shipped. Cooling is a major bottleneck, because capital for refrigeration is not unlimited. Likewise any delay can be a major issue- if a truck is slow to load, how do you know whether or not you need to re-cool your produce first?
It's well known what temperatures produce does well at (can't be too hot or too cold without MAJORLY affecting end margins) because it's easy to test by setting a fridge to a given temperature. It's much harder to know, for a given type of produce, how fast it will cool or heat, and how long you need to spend doing that. It's not as simple as sticking a thermometer in it, which will create paths for heat to move into and out of the produce. Even then you still don't know what the heat distribution inside the produce is so you can optimize the temperature over as much of the plant as possible.
It's really quite tricky and stuff like this helps farmers a lot. IMO farmers do more actual number math more than almost any other occupation (ex: [1]). Much of it is rules of thumb and guesstimation, but they still are constantly balancing dozens of figures to make choices every day. They're always doing mental calculations in economics, biology and physics. Even if the job wasn't so physically and technically taxing, I would respect the hell out of them just because of the mental workload.
[1] https://youtu.be/ywBV6M7VOFU?t=630
Harvest time is extremely hectic. There's a very small window to get months worth of produce picked, sorted, cooled, packed and shipped. Cooling is a major bottleneck, because capital for refrigeration is not unlimited. Likewise any delay can be a major issue- if a truck is slow to load, how do you know whether or not you need to re-cool your produce first?
It's well known what temperatures produce does well at (can't be too hot or too cold without MAJORLY affecting end margins) because it's easy to test by setting a fridge to a given temperature. It's much harder to know, for a given type of produce, how fast it will cool or heat, and how long you need to spend doing that. It's not as simple as sticking a thermometer in it, which will create paths for heat to move into and out of the produce. Even then you still don't know what the heat distribution inside the produce is so you can optimize the temperature over as much of the plant as possible.
It's really quite tricky and stuff like this helps farmers a lot. IMO farmers do more actual number math more than almost any other occupation (ex: [1]). Much of it is rules of thumb and guesstimation, but they still are constantly balancing dozens of figures to make choices every day. They're always doing mental calculations in economics, biology and physics. Even if the job wasn't so physically and technically taxing, I would respect the hell out of them just because of the mental workload.
[1] https://youtu.be/ywBV6M7VOFU?t=630
And here am I the doofus who works in Accounting Software often saying "I should have done something with fruit" when my work involves too much math for my liking.
I'll try to stop using that from now on, thanks!
I'll try to stop using that from now on, thanks!
I heard (no refernece, sorry) that oranges do from green to orange when the temperature drops. Apparently colour change does not affect taste, nor necessarily indicate ripeness. Would anyone knowledgeable please chip in and correct or elaborate on this please.
"I'm now consumed with curiosity why this plant has evolved to have this feature."
Grapefruit didn't evolve naturally. In fact, it's only a couple of hundred years old. It's the way it is because of human intervention.
Grapefruit didn't evolve naturally. In fact, it's only a couple of hundred years old. It's the way it is because of human intervention.
Absolutely. I also have a pomelo tree, though it's still in a pot in the shadehouse, and produces a single (enormous) fruit each year.
Grapefruit are a cross, probably, of pomelo and a sweet orange - as you say, not all that long ago. While some grapefruit varieties are quite pithy, pomelos (that I've seen) are very pithy - hence the 'this can only have been even more expensive a protective layer in earlier versions of this plant'.
The question still stands - why is this adaptation useful, given it's probably expensive. (That assumption of mine may be entirely wrong.)
Early species would have been shorter, and all species in the history of this would have fruited long before the individual trees reached 10 metres (I'm guessing even in ideal conditions that implies 10+ years growth). Most would-be consumers of the fruit would be able to reach fruit within the first metre or so (if unable to climb or fly) and anywhere in the tree otherwise.
Grapefruit are a cross, probably, of pomelo and a sweet orange - as you say, not all that long ago. While some grapefruit varieties are quite pithy, pomelos (that I've seen) are very pithy - hence the 'this can only have been even more expensive a protective layer in earlier versions of this plant'.
The question still stands - why is this adaptation useful, given it's probably expensive. (That assumption of mine may be entirely wrong.)
Early species would have been shorter, and all species in the history of this would have fruited long before the individual trees reached 10 metres (I'm guessing even in ideal conditions that implies 10+ years growth). Most would-be consumers of the fruit would be able to reach fruit within the first metre or so (if unable to climb or fly) and anywhere in the tree otherwise.
Interesting. There are other fruit & seeds out there that develop strong exocarp or mesocarp (think coconut) and I believe it has to do with wanting the fruit to travel longer distances to encourage geographic spread. The plant probably "prefers" that the seedlings take hold some distance from the parent, so wants the seed preserved longer and taken away by certain kinds of animals (hairless apes!)
What kind of animals live, or lived, in wild citrus' native range? Now I'm curious. [EDIT: Himalayan foothills... Macaques? Elephants?]
Or it's selected for particular animals as spreaders? In wild grapes, for example, most are adapted for bird spread (small dark acidic berry, high up in a tree on dangling shoots) but there are a handful of species (vitis labrusca "fox grape" for example, and vitis rotundifolia aka muscadines) that have adapted for mammals and they are quite different: larger berry, lighter colours, strong smell (think Concord), lower acids, slip skin, and a tendency to "shell" (fall off the vine when ripe). They also tend to grow wild in shadier moister areas, e.g. the underbrush where foxes and skunks and racoons etc. will grab them, not birds.
What kind of animals live, or lived, in wild citrus' native range? Now I'm curious. [EDIT: Himalayan foothills... Macaques? Elephants?]
Or it's selected for particular animals as spreaders? In wild grapes, for example, most are adapted for bird spread (small dark acidic berry, high up in a tree on dangling shoots) but there are a handful of species (vitis labrusca "fox grape" for example, and vitis rotundifolia aka muscadines) that have adapted for mammals and they are quite different: larger berry, lighter colours, strong smell (think Concord), lower acids, slip skin, and a tendency to "shell" (fall off the vine when ripe). They also tend to grow wild in shadier moister areas, e.g. the underbrush where foxes and skunks and racoons etc. will grab them, not birds.
All I'm finding is 'south east Asia' as origin -- which is an enormous range of fauna.
I understand the 'travel far and wide', though of course evolution's not directed, and is there significant difference in fitness & success over the long term for a variation that allows a plant to produce offspring 1km away in one generation (say 5y), rather than taking 2 generations?
(And, of course, it's worse than that. The 10m drop potential isn't realised until the plant is probably 15 years old or more -- at which point the distance / propagation calculation is almost irrelevant, as that specimen would have produced fruit for at least 5 years whose seeds would have travelled the same distances, regardless of this (future) robustness capability.)
Sadly, though, I suspect plant archaeologists have more pressing concerns than this question.
I understand the 'travel far and wide', though of course evolution's not directed, and is there significant difference in fitness & success over the long term for a variation that allows a plant to produce offspring 1km away in one generation (say 5y), rather than taking 2 generations?
(And, of course, it's worse than that. The 10m drop potential isn't realised until the plant is probably 15 years old or more -- at which point the distance / propagation calculation is almost irrelevant, as that specimen would have produced fruit for at least 5 years whose seeds would have travelled the same distances, regardless of this (future) robustness capability.)
Sadly, though, I suspect plant archaeologists have more pressing concerns than this question.
Gotta love HN; I click comments and am met with screenfulls about grapefruit.
Also submitted here: https://news.ycombinator.com/item?id=23903596
> The blade is gradually eroded, and eventually rendered ineffective as the force and energy of the disc or the drill is turned back on itself, and it is weakened and destroyed by its own attack.
What about an angle grinder disc made of this new material?
What about an angle grinder disc made of this new material?
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There seems to by multiple different types of material incorporated, and I'm not sure that would work in a blade, where it's really the tip/edge that comes into contact.
They don’t mention what kind of blade was used in the experiment? Interested if it was a diamond blade or a conventional blade.
When pausing the video it looks like a conventional cut off wheel.
When pausing the video it looks like a conventional cut off wheel.
It's an alumina fiber reinforced blade, same ceramic as in the material. It's the most common grinding wheel material.
Diamond blades are not especially good at cutting. They only used when absolutely necessary, ie when your material is extremely hard. Diamond sublimates at low temperatures, it dulls quickly because of the fracture planes, and it's so weak and brittle that only tiny grains can survive being used to cut.
The alumina spheres they use are softer than diamond, but handle the cutting environment much better. Zirconia wheels handle cutting even better (up to 10x better) than alumina, but its softer. No idea what would be ideal.
Loading a power washer with some expensive abrasives would still cut this fairly quickly, and a thermic torch would cut it very quickly. Kind of requires you to not care about what's actually on the inside, though.
Diamond blades are not especially good at cutting. They only used when absolutely necessary, ie when your material is extremely hard. Diamond sublimates at low temperatures, it dulls quickly because of the fracture planes, and it's so weak and brittle that only tiny grains can survive being used to cut.
The alumina spheres they use are softer than diamond, but handle the cutting environment much better. Zirconia wheels handle cutting even better (up to 10x better) than alumina, but its softer. No idea what would be ideal.
Loading a power washer with some expensive abrasives would still cut this fairly quickly, and a thermic torch would cut it very quickly. Kind of requires you to not care about what's actually on the inside, though.
I use diamond metal blades because I don’t want my blade turning into shrapnel.
It would probably not be very good at cutting, and would just get very hot. Just because the blade doesn't wear away doesn't make it good at cutting.
One way to make something resist abrasives is for it to be/sustain very high temperatures. If you can survive a hotter temperature than the abrasive (quite low for diamond, higher for sapphire) then it will be much less effective.
One way to make something resist abrasives is for it to be/sustain very high temperatures. If you can survive a hotter temperature than the abrasive (quite low for diamond, higher for sapphire) then it will be much less effective.
Pretty sure once this new material gets hot enough the aluminium substrate will melt and it'll cut just as well as anything else.
You'd need direct heating, a conventional blade still would not work. The alumina spheres hold off the cutting edges and block heat flow from hotspots. A small amount of aluminum foam will melt, but once it's far enough away from the hot zone it'll just serve to conduct heat away from the ceramic much more rapidly than it otherwise would.
It's aluminium foam, meaning it wouldn't do very well with heat or tension.
Neat idea, very similar to concept of running a chain through a pipe to prevent cutting, but in three dimensions. I do wonder what effect freezing would have on it though.
>Neat idea, very similar to concept of running a chain through a pipe to prevent cutting
People do that? Also, how does it work?
People do that? Also, how does it work?
The grates that protect prison windows are often made of pipes with a bunch of loose rods inside. Cutting through the pipe itself is relatively easy, but the rods inside are unfastened, so they tend to roll under the cutting tools.
Edit: The principle is actually somewhat similar to the anti-drill protection on door locks - a small disc in front of the lock with a slit that the key goes through. The disc makes it hard to drill through the lock, because it spins together with the drill.
Edit: The principle is actually somewhat similar to the anti-drill protection on door locks - a small disc in front of the lock with a slit that the key goes through. The disc makes it hard to drill through the lock, because it spins together with the drill.
> The cellular structure showed significant deformability, exceeding 20% of engineering strain as expected from previous studies of cellular metals
This only talks about the cellular structure, not the overall material structure, but would this mean that the material would start to deform under a heavier strain? Does that mean it would make sense to not use this material alone, but rather with other materials to make a strong product, e.g. a bike lock with this material on the outside of a thin but rigid pure metal core?
This only talks about the cellular structure, not the overall material structure, but would this mean that the material would start to deform under a heavier strain? Does that mean it would make sense to not use this material alone, but rather with other materials to make a strong product, e.g. a bike lock with this material on the outside of a thin but rigid pure metal core?
>ceramic spheres encased in a cellular aluminum structure
sounds like the modern "ceramic in a metal matrix" tank armor:
https://en.wikipedia.org/wiki/Chobham_armour
"The (pulverised) ceramic also strongly abrades any penetrator. Against lighter projectiles the hardness of the tiles causes a "shatter gap" effect: a higher velocity will, within a certain velocity range (the "gap"), not lead to a deeper penetration but destroy the projectile itself instead."
From the article on the material
"Water jets were also found to be ineffective because the curved surfaces of the ceramic spheres widen the jet, which substantially reduces its speed and weakens its cutting capacity."
Not just water jet, the ceramic/metal armor withstands even shaped charge jet :
"Because the ceramic is so brittle the entrance channel of a shaped charge jet is not smooth—as it would be when penetrating a metal—but ragged, causing extreme asymmetric pressures which disturb the geometry of the jet, on which its penetrative capabilities are critically dependent as its mass is relatively low. This initiates a vicious circle as the disturbed jet causes still greater irregularities in the ceramic, until in the end it is defeated. The newer composites, though tougher, optimise this effect as tiles made with them have a layered internal structure conducive to it, causing "crack deflection".[2] This mechanism—using the jet's own energy against it—has caused the effects of Chobham to be compared to those of reactive armour."
sounds like the modern "ceramic in a metal matrix" tank armor:
https://en.wikipedia.org/wiki/Chobham_armour
"The (pulverised) ceramic also strongly abrades any penetrator. Against lighter projectiles the hardness of the tiles causes a "shatter gap" effect: a higher velocity will, within a certain velocity range (the "gap"), not lead to a deeper penetration but destroy the projectile itself instead."
From the article on the material
"Water jets were also found to be ineffective because the curved surfaces of the ceramic spheres widen the jet, which substantially reduces its speed and weakens its cutting capacity."
Not just water jet, the ceramic/metal armor withstands even shaped charge jet :
"Because the ceramic is so brittle the entrance channel of a shaped charge jet is not smooth—as it would be when penetrating a metal—but ragged, causing extreme asymmetric pressures which disturb the geometry of the jet, on which its penetrative capabilities are critically dependent as its mass is relatively low. This initiates a vicious circle as the disturbed jet causes still greater irregularities in the ceramic, until in the end it is defeated. The newer composites, though tougher, optimise this effect as tiles made with them have a layered internal structure conducive to it, causing "crack deflection".[2] This mechanism—using the jet's own energy against it—has caused the effects of Chobham to be compared to those of reactive armour."
it's more similar to older composite armour, the t64 used something similar before they switched to the multilayer armour with glass reinforced plastic
https://m.imgur.com/NA8gcCE
It was abandoned not because ineffectiveness but because construction difficulties, uniformity of the embedded spheres was hard to maintain
https://m.imgur.com/NA8gcCE
It was abandoned not because ineffectiveness but because construction difficulties, uniformity of the embedded spheres was hard to maintain
That’s pretty cool. can it be cut with bolt cutters or such?
They have used a cheap angle grinder disk, what would have happened if they took a proper diamond one?
I feel like it says a lot about the HN audience that the biggest reply chain is about bike locks, of all things.
Why? Bike locks are surely the most common thing people have experience of being cut that they don't want to be cut.
Did anyone actually read the article? The aluminum foam material has to be thick and the ceramic beads are large.
Also, even if you just looked at the angle grinder video, you can see the claims aren’t really as presented. It’s very cutable, it just happens to eventually dull the cutter eventually. That’s what, a 2” billet they have there?
For their demo on a similar thickness steel plate, I think that most people would have an extremely hard time getting that far in 17-4PH steel let alone SS6xx like Inconel or any one of 100 different steels.
Mostly you would stop from boredom even in a world where the grinder wasn’t similarly full or broken by the time you gave up.
Also, even if you just looked at the angle grinder video, you can see the claims aren’t really as presented. It’s very cutable, it just happens to eventually dull the cutter eventually. That’s what, a 2” billet they have there?
For their demo on a similar thickness steel plate, I think that most people would have an extremely hard time getting that far in 17-4PH steel let alone SS6xx like Inconel or any one of 100 different steels.
Mostly you would stop from boredom even in a world where the grinder wasn’t similarly full or broken by the time you gave up.
Yes I did watch the video, and yes I agree it would be fairly useless for bike locks. Though there is a very expensive bike lock that has an aluminium surround the try to foil small angle grinders (the idea is that it is too thick for the discs to get through). Would be useful for that.
What about cicular saw with diamond blade? You can cut cement, ceramics and granite with it... What about demolition hammer or hammer drill?
Looks like a conventional cut off wheel in the video, not a diamond blade.
Heard that one before https://www.dailymotion.com/video/x2p7a6d
Aluminum. A highly reactive metal prone to rapid decomposition in household drain cleaner. Yeah, this isn't going to revolutionize bike locks.
I can't see the improvement of this vs. walls of high end personal safes. They have used mixed material walls for ages, made from some hard small component (e.g. ceramic) embedded in a more flexible mass (hard rubber).
Being accepted in SciRep this material has to have some merit but I am unable to see it.
Is the structure even scalable to smaller objects? The other comments talking about bike looks did not read the paper it seems.
Being accepted in SciRep this material has to have some merit but I am unable to see it.
Is the structure even scalable to smaller objects? The other comments talking about bike looks did not read the paper it seems.
Nothing in there on its electrical properties. Can it be cut using a plasma cutter?
Given that its ceramic beads embedded in aluminum foam, I would guess any heat-based cutter would make short work of it. But then again, I would also guess a diamond blade meant for ceramics would go farther than the standard abrasive cut-off wheel meant for soft metals that they showed in the video.
I'm not sure "non-cuttable" is the best description, it is cuttable, but it messes the tools
"Cutting resistant" might be a better description, and it is an interesting material regardless
Sounds like it works for applications where you need something to absorb "stopping" energy but without wearing out (too much)
"Cutting resistant" might be a better description, and it is an interesting material regardless
Sounds like it works for applications where you need something to absorb "stopping" energy but without wearing out (too much)
Agreed - that angle grinder got through it fairly quickly I would say. I mean, slower than other material, sure. But it still cut it.
One may need to use an angle grinder correctly in a video to convince me. The demo where they plunge the angle grinder straight into the material is no different than the effect on hardened steel. Typically you would start at an edge to minimize the contact area of the cut. That's why lock shackles are rounded.
Yea. I can absolutely guarantee they wouldn’t get nearly as far as they did with a really hard steel like 600-series stainless (Inconel).
I’m certain this is a novel approach with their “jelly filled with nuggets” but it’s still jelly... let me know when they embed nugget in steel.
I’m certain this is a novel approach with their “jelly filled with nuggets” but it’s still jelly... let me know when they embed nugget in steel.
I think they are cutting into the steel plate that they welded to it. Doesn't look like they get that far into the actual material. I agree with the point about using the grinder correctly though.
You do not (cannot) weld steel to aluminum.
This looks like aluminum billet to me. And other than the grinder stopping, it looks like it’s cutting exactly like aluminum.
This looks like aluminum billet to me. And other than the grinder stopping, it looks like it’s cutting exactly like aluminum.
Sure, it doesn't really matter if it is steel or aluminum. They are cutting into the plate that is welded to the material. It still appears to stop once it gets through the plate.
Can Proteus be cut by Proteus?
Interesting. Now this is worthy of a patent.
So the material stops the cutting action, by having air sacs inside itself, where the particulate inside would melt from the friction, and cause the cutter blade to jam itself up.
So the material stops the cutting action, by having air sacs inside itself, where the particulate inside would melt from the friction, and cause the cutter blade to jam itself up.