[HN Gopher] Smart METL airless metal bike tires use a "shape mem...
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Smart METL airless metal bike tires use a "shape memory alloy" for
deformation
Author : giuliomagnifico
Score : 46 points
Date : 2021-03-18 11:13 UTC (11 hours ago)
(HTM) web link (cyclingtips.com)
(TXT) w3m dump (cyclingtips.com)
| mc32 wrote:
| What happens when you go over sand or mud?
|
| Do things get trapped in there? Is it like a mix-master with
| thick dough and it gets all clogged up and you better wash it
| before lumpy things harden?
| c0nsumer wrote:
| Heck, it'd be terrible the moment some dirt or mud pushes
| through and makes the wheel heavy on one side.
| hugey010 wrote:
| One of the simplest and most common mods to off-road vehicles is
| called a tire mousse. It's basically foam or rubber that replaces
| the inflatable tube. The benefits are never getting a flat, and
| not having to carry a spare tube, tools, or patches. There's some
| efficiency loss which may be too much for a commuter bicycle, but
| it looks like they exist for mountain and e-bikes.
| yodelshady wrote:
| FYI, reasons why air works _really well_ as a suspension medium:
|
| * stiffness-to-weight is high and hysteresis low. That means a)
| easily adjusting the compliance for different weights, b)
| excellent traction, since the "spring" isn't fighting its own
| inertia.
|
| * in normal operations, essentially unlimited durability, because
| there's no long-range order to break down. Let's see how these do
| after a million or so cycles.
|
| * when something _does_ break your suspension, you 're literally
| surrounded by the repair material. Again, let's see airless
| compete with that. The road is a very hostile surface. I've seen
| more than one well-meaning group try "ruggedised" tyres that
| became useless well before I'd even expect a puncture from a
| decent road tyre.
| Valgrim wrote:
| You're absolutely right, but I'm still happy that someone
| created a full-size prototype of it outside the lab, and is
| testing it, tinkering with it and putting it out there so
| people can also try it and experiment with it. I don't know
| what this could lead to, maybe some sort of hybrid air-filled
| spring loaded undestructible bike tire, maybe it's going to
| end-up in a completely different application, such as
| wheelchairs or farming tractors or mining equipment.
| mdip wrote:
| Frankly, a tire that could maintain 80% of its performance
| under circumstances that a run-flat or standard tire would
| "blow-out" would be the difference between life and death on
| a motorcycle. Run-flat tires don't protect (enough) from
| blow-out, only puncture, which are handled well by most
| automotive/motorcycle tires, already. I realize the risk of
| blow-out is pretty low, but I've had it happen to me[0] --
| regardless of how low a risk, I'd pay 4-5 times as much per
| tire on my motorcycle for being able to increase my chances
| of survival should that happen.
|
| [0] I probably don't need to mention this happened to me in a
| _car_ since I 'm not writing this from the afterlife.
| ska wrote:
| It's an interesting idea, but the fraction of motorcycle
| fatalities caused by blow-outs is so minuscule it's far
| more likely the decreased performance overall of this tire
| would cause far more.
|
| Unless you are assuming equivalent performance, which seems
| unlikely. Modern motorcycle tires are incredibly good, even
| (with appropriate ones) in rain.
| zbrozek wrote:
| I'm also glad folks are tinkering. That said, bike tires are
| probably not where I would expect something like this to
| land. I would love these to replace the tires on things like
| utility carts, air compressors, etc that typically end up
| with solid tires. Those solid tires are awful, but pneumatic
| ones must be filled and that's annoying for infrequently used
| stuff.
| analog31 wrote:
| Agreed. I happen to enjoy the hobby of tinkering with old
| bikes, so my bikes are typically a few decades behind the
| latest technology. So I can adopt a wait-and-see
| philosophy.
|
| But still I remember a cynical comment by my dad, maybe 40
| years ago. They had just announced some new advanced
| material, and my dad said: "Mark my words, the first
| applications will be high end bikes and golf clubs." Also,
| improving on the bicycle is a very common capstone project
| for design students.
| mdip wrote:
| I have always wondered why we accept the risk of "the thing
| holding you to the road just falling apart underneath you". I
| suspected it had to be _really good at what it did when it
| worked_ but wasn 't sure what that is.
|
| So, today I learned what a _suspension medium_ and _hysteresis_
| is, but more importantly, why replacing "the tire" with
| something which eliminates the one safety issue would result in
| a number of other issues (some of which reduce safety in more
| serious ways than the risk of blow-out). Thanks for that!
| dasKrokodil wrote:
| I usually try to stay open-minded towards any new inventions, but
| there have been sooo many failed attempts at replacing pneumatic
| rubber tires that I'm very skeptical whenever a new one is made.
| Best of luck to them, but I'm not holding my breath.
| 0_____0 wrote:
| The bicycle itself is highly resistant to change as well. The
| overall concept basically hasn't changed for over a hundred
| years. Just small tweaks here and there.
| analog31 wrote:
| Oddly enough the human body also hasn't changed much. I've
| noticed this in some other technologies as well, such as the
| electric bass guitar, which I play. The electric bass settled
| on a fairly standardized geometry within a few years of it
| being invented. And while there have been some experiments
| and oddball instruments made over the years, the bread and
| butter instrument still looks pretty much like the original
| Fender bass with some tweaks. I've tried some of the
| modernizations, and they're physically awkward to play. There
| was a period of basses with sexy long necks and tiny little
| bodies, and they all suffered from "neck dive."
|
| Still, while I ride a bike that would not have looked out of
| place in 1890 when viewed from a distance, on closer
| inspection a lot of things have been improved. Perhaps most
| importantly, all of the newer materials are better, including
| high performance steel, aluminum, tires, and so forth.
| Hydroforming and carbon fiber layup have finally made it
| possible to experiment with more interesting frame shapes.
| jfengel wrote:
| There are a lot of alternative bike geometries that go a
| lot faster than the standard bike position. They reduce
| wind resistance and/or have better biomechanics. The lack
| of change has more to do with Union Cycliste Internationale
| rules than with optimization.
| analog31 wrote:
| Indeed, and in fact I see a lot of recumbents in my
| locale on the longer, flatter bike paths. Not so much in
| urban traffic. So a bike that's adapted to the human body
| doesn't mean there's not a better adaptation for some
| uses.
|
| And I'm certainly not averse to trying one someday -- N+1
| and all that. There's a shop in my locale dedicated to
| them. However, I think the mass market for bikes has
| diverged from the racing world. Most bikes sold today are
| of styles such as cruisers, hybrids, and low tech
| mountain bikes, that are unrelated to racing categories.
| Even many racing style bikes such as gravel and cyclo are
| bought with the intention of using them "off label" if
| you will, just because they look comfortable and rugged.
| So the UCI isn't holding us back any more.
|
| Hell, there's the whole category of e-bikes. That's
| probably the biggest threat to the market for more
| efficient human powered bikes.
| fanf2 wrote:
| That's mostly because the UCI has very strict rules about
| bicycle design. They banned recumbent bikes very early in the
| history of the sport; more recently they banned Graeme
| Obree's "superman" position and other changes to the geometry
| of a normal upright.
|
| http://www.wolfgang-menn.de/superpos.htm
|
| https://www.bikeradar.com/features/top-five-banned-tech-
| the-...
|
| Check out Mike Burrows for some interesting bike designs.
| Check out the Battle Mountain speed records for what the
| highest performance bikes look like.
| throwaway0a5e wrote:
| Not to mention that if bicycles ever get something like this
| it'll be 30yr after applications where puncture resistance is a
| high priority (i.e. everything you see using solid tires today)
| gets them.
| awelkie wrote:
| So the article says the technology was developed at NASA and then
| licensed to Smart via the "Space Act Agreement". It looks like
| the company has three patents already, one of which[0] seems (to
| me, after a brief glance) to cover the essential innovation
| behind the metal tires.
|
| Can anyone tell me how the Space Act Agreement works? Does the
| innovation developed by NASA end up as a patent for a chosen
| company? Or do these three patents represent work done by the
| company and not at NASA? If it's the former, does NASA get any
| money from this agreement?
|
| [0]: https://patents.google.com/patent/US10449804B1/en
| wil421 wrote:
| The patent you linked to is under NASA and the NASA employees
| who came up with the tech.
|
| What do the company's patents say and detail?
| awelkie wrote:
| Ah good catch! The reason I thought the patent was assigned
| to the Smart company was because they list it in their
| Wefunder page[0] (under the heading "Key Accomplishments").
| But actually all that's stated on that page is that "multiple
| patents protect this innovation", they don't actually claim
| that they have the patents.
|
| I'm still curious how the licensing from NASA works. Do they
| typically grant a monopoly to certain companies or can
| multiple competing companies license this technology?
|
| [0]: https://wefunder.com/the.smart.tire.company
| dpiers wrote:
| It depends. NASA will file a notice of intent to grant an
| exclusive or partial license - you can see the notices
| here[1].
|
| In this case it seems the patent is still available for
| anyone to license[2]. They have special licensing terms for
| startups that are pretty favorable[3].
|
| 1: https://www.federalregister.gov/documents/search?conditi
| ons%...
|
| 2: https://technology.nasa.gov/patent/LEW-TOPS-99
|
| 3: https://technology.nasa.gov/startup
| Mizza wrote:
| More importantly - why do innovations by NASA not go into the
| public domain?
|
| Our tax dollars paid for it, our homemade battlebots should be
| armored by it.
| V_Terranova_Jr wrote:
| NASA does publish on much of its research. See, e.g.:
| https://ntrs.nasa.gov/
|
| There are other forums in which they publish export-
| controlled information.
|
| They patent things for at least two reasons. One is
| monetization - some in Government believe that monetization
| helps recoup some of the taxpayer's R&D contributions by
| claiming a "rightful" share of the benefits to commercial
| entities. I'm not saying I agree with this, just that is it a
| commonly held viewpoint.
|
| Another, even in cases where the licensing is royalty-free,
| is for defensive purposes. It ensures a benevolent entity
| owns the patent and can license it for implementation in an
| equitable and non-discriminatory way.
|
| Practically speaking, if you were to implement NASA-patented
| technology in a non-commercial context (homemade battlebot),
| it's extremely unlikely NASA would come after you for patent
| infringement.
| geocrasher wrote:
| Yet another solution looking for a problem to solve. We don't
| need better tires. We have them. They're called 'pneumatic' and
| in the late 1800's they were a significant advancement in
| technology. They provide a great ride, great traction, and are
| straightforward to repair. I seriously doubt whether "Smart METL"
| airless tires meet those same marks.
| m463 wrote:
| I think there are significant usability problems with wheels
| and tires that can be tackled.
|
| For example, tires lose air on a daily basis and have to be
| pumped up. Additionally, even the best pumps require a bunch of
| fidding to attach and detach the hose to the air fitting.
|
| Tires and suspension are a tradeoff between comfort and
| efficiency. Lower rolling resistance means a stiffer/harsher
| ride. High pressure tires are narrow, have a very small contact
| patch and no "suspension travel"
|
| Even though it's cliche, I think reinventing the wheel might
| take us interesting places.
| jfengel wrote:
| Repair isn't that straightforward. It requires you to remove
| the wheel, and then the tire. You then replace the inner tube
| and re-mount the tire bead, which requires some practice to get
| right. Then you have to re-pump it. An expert can do it
| quickly, but it's a hassle for an amateur out for a cruise.
|
| It's also limited by the tubes and/or patches you've brought
| with you. If you blow a tube, you should have a spare. If you
| lose a second tube, you may be out of luck. Maybe it can be
| patched, though I've found patching unreliable. You may be in
| for a long walk, in your cycling shoes -- especially if you've
| ridden out of cell phone range.
|
| These are clearly going to be far beyond the price point of
| your casual rider, at least for a while. But if they can match
| the ride experience, and eventually lower the price, I could
| see these being wildly popular.
|
| Pneumatic tires are hard to beat, but there's a lot of room for
| improvement in their durability. Which is really important for
| something you depend on so much.
| jiofih wrote:
| > Polyurethanium. We have no idea what this is and Smart provided
| no detail.
|
| That was funny. The bad news: polyurethane is a type of plastic,
| already used as a replacement for rubber in some kinds of tires.
| AtlasBarfed wrote:
| I guess if the metal is doing 99% of the support work, then you
| might be able to "spray on" grip.
|
| This might be SUPER IMPORTANT if it's biodegradable, with all
| the stories about the noxious effects of car tire wear
| particles impacting the environment.
|
| Since the "grip" doesn't need to do the support job, we can use
| a more fragile compound.
| interestica wrote:
| Is there a company named "Smart" in every domain?
| cardiffspaceman wrote:
| And every such name is just waiting for someone who has a bad
| experience due to a flaw, and christens it 'Stupid'. To avoid
| this phenomenon name your "Smart Pointer" "RefCountingPointer"
| not "SmartPtr".
| ballenf wrote:
| I think this is more so just spring steel. Unless there's a heat
| source hidden in there.
|
| It's also kind of funny that they admit they'll have to wrap the
| metal in a rubbery substance for traction.
|
| So we're pretty much back at steel radial tires.
| mdip wrote:
| I wonder, though, if the rubber can be more rugged as a result.
|
| Materials/chemistry is so far out of my wheelhouse, I can't
| even imagine what that might be. But I'd imagine there might be
| a way to optimize the synthetic rubber for handling friction
| against the road surface while not having to optimize it for
| handling pneumatic pressure.
|
| Unfortunately, I suspect that the things done to make the tire
| survive road friction better also make it grip the road worse.
| And that there's likely not a chemical formula that one can
| apply which wouldn't work equally well under a pressurized
| tire... but hey, most things are evolution, not revolution,
| anyway, right?
| Robotbeat wrote:
| In a way, yeah it is a better spring steel. Many shape memory
| alloys, besides their famous shape-changing-under-heating
| behavior, can also have superelastic properties, meaning they
| can reversible handle much larger strains than typical alloys
| (by a reversible phase change in the material). This means they
| can work as a better spring alloy.
| https://en.wikipedia.org/wiki/Pseudoelasticity
| scythe wrote:
| Nitinol typically has tight compositional tolerances and is
| used for things like stents and catheters. It's nothing new
| in the medical field. But it'd be pretty damn impressive to
| manufacture something so finely structured out of nitinol at
| scale.
| Robotbeat wrote:
| Oh, it's not that uncommon. You can buy Nitinol wire pretty
| cheaply, although not the medical-approved stuff.
| itronitron wrote:
| I could see these being _much_ better for mountain bikes than
| for road bikes as the woven surface might actually improve
| traction on mountain bike trails.
| tyingq wrote:
| _" Polyurethanium"_ ???
|
| Surely there's a real word they could use there.
| meepmorp wrote:
| I keep reading it as 'poly-urethra-radium'
| dylan604 wrote:
| Like unobtanium? If they use a real word, they wouldn't be able
| to trade mark it and protect their brand. Sounds like people
| are taking cues from big pharma with naming, or silicon valley
| by taking real words and dropping vowels. It's a trend. Why is
| this surprising to you?
| 5560675260 wrote:
| Polyurethane [0] is a real world. Maybe that's what they meant?
|
| [0] https://en.wikipedia.org/wiki/Polyurethane
| tyingq wrote:
| No, they trademarked the term, so it's definitely on purpose.
| stdbrouw wrote:
| Also, if this is some kind of polyurethane, they're going to
| have a hard time convincing anyone that this is an
| environmentally friendly alternative to rubber tires.
| lolc wrote:
| Haha, they look so cool!
|
| Given that the mesh has an uneven surface though, I don't see how
| they could compare well to the resistance of a tire with a smooth
| surface.
|
| Also, it looks like the coating would have to be reapplied often
| because it's so thin.
|
| And small objects could start to accumulate inside, no?
|
| The more I think about them, the more impractical they seem.
| Would still love to try them though.
| Cthulhu_ wrote:
| These look like they'd be full of sand and rocks rattling around
| really fast.
| meepmorp wrote:
| The article specifically mentions that the exterior will be
| wrapped in some rubbery material, with the very silly name
| polyurethanium.
| senectus1 wrote:
| not only that but ruin your rims when you hit a kerb or
| something.
|
| Also I'd be really concerned about how much grip it'd retain on
| a sandy concrete corner..
| sandworm101 wrote:
| Mars? I think not. This woven-metal tire tech was around long
| before the mars rovers.
|
| https://airandspace.si.edu/collection-objects/wheel-lunar-ro...
|
| https://www.nasa.gov/specials/wheels/
|
| And can someone explain to me what "shape memory alloy" means in
| this context? Iirc that means a metal that will return to a shape
| _when heated_. So I blowtorch these bike tires every few days to
| iron out dents? Or are these just spring steel, metal that
| bounces back into shape so long as it isn 't push beyond its
| yield point?
| wil421 wrote:
| They developed the shape memory part recently while developing
| a new wheel for the Mars rover.
|
| From your NASA link:
|
| " In one particular moment of serendipity, Engineer Colin
| Creager and Materials Scientist Santo Padula had a conversation
| that completely changed the path forward.
|
| The game changing material that dramatically advanced the
| development of spring tires was nickel titanium, a shape memory
| alloy with amazing capabilities as explained by Santo Padula."
| brennanpeterson wrote:
| Woven metal tires are old. And nitinol is also old (it was not
| developed for the rover, a wiki check would show as much).
|
| But the combination is new. I imagine the conversation went
| 'hey I am working on chainmail tires' 'areny those heavy'
| 'well. We need them light, strong and elastic, and you only get
| two...' ' hol up, there is an option, you heard of nitinol?'
|
| And thus, cool history.
| musingsole wrote:
| Not a shape alloy expert, but the temperature that causes them
| to morph can be manipulated when they're formed (forged?). I
| have a few strands that just the heat from your hand is often
| enough to trigger them.
|
| So, the heat from friction is potentially an option.
| buescher wrote:
| Nickel-titanium ("nitinol") shape-memory alloys are also
| "superelastic", which means they have an additional range of
| deformation past normal elastic deformation before plastic
| deformation from which they return back to their original
| shape. So, not just spring steel.
| cbsks wrote:
| This video has a clear explanation of the shape metal alloy on
| the Mars rover wheel: https://youtu.be/2lv6Vs12jLc
|
| Short answer is that the material is super elastic, and will
| return to its original shape either when heat is applied, _or_
| when stress is applied.
| mdip wrote:
| I kind of takes tires for granted in a lot of ways. My assumption
| was that technology around the "tire" wasn't going to change
| substantially any time soon and there has to be a number of very
| good reasons I'm unaware of as to why we accept the risk of blow-
| out for the remaining benefits of the technology (the article
| mentions road grip, but yodelshady in the comments mentioning
| _suspension medium_ explained the reasoning really well).
|
| A lot of thought has been put toward reducing "blow-out" and
| other risks associated with "rolling around on a balloon". I
| started looking at "run-flat tires" after having suffered a blow-
| out on the road at 70MPH on defective (two-day old) tires and
| experiencing what it really is like to have your life "in God's
| hands" for twenty long seconds. I was in my car, that time -- had
| it been a blow-out on my motorcycle...
|
| After some research and discussion with a trusted mechanic, I
| opted to save $100-or-so/tire[0] and skip the technology. I
| _wanted_ tires that I wouldn 't have to concern myself with the
| pressure, I was being sold tires that handle a nail pretty well.
|
| Having suffered a blow-out in a car, it's something that's on my
| mind on my motorcycle. There's just _not_ a lot you can do -- the
| best tires are designed to prevent the typical causes of this but
| defects in the tire /chemicals involved can make it _impossible_
| to verify that the tire is safe to ride on prior to use for
| certain defects. Some won 't be an issue until the tire has been
| driven at speed enough for it to reach a certain temperature
| (that was my issue) and there won't be a scar or bubble on the
| tire where it's about to fail.
|
| So all of this to say -- this looks like a _really_ excellent
| thing if they can truly eliminate pressurized air and maintain
| the performance of a regular tire (while not costing an
| unrealistic amount -- that 's probably tricky). I doubt it would
| "eliminate the tire" in every application -- it makes sense to
| start with bikes -- but I'll be an early customer when they have
| a motorcycle tire replacement. :)
|
| [0] His explanation was that they'll let you get to the shop if
| you "roll over the business end of a screw". Regular tires are
| designed to handle punctures gracefully, already. Run flat will
| do a little better than a regular tire but they blow out,
| especially if the car doesn't have a pressure monitor because the
| tires don't appear to be as low as they are, causing the driver
| to damage the tire rapidly. He also confirmed my suspicion: "It's
| a pretty safe bet that if the tire has 1,000 miles on it, it
| won't blow out until after you should have replaced it" --
| basically, brand new and really old tires are the ones that just
| spontaneously "fall apart".
| dmayle wrote:
| I received a pair of Tannus Airless tires (
| https://tannustires.com/ ) for christmas, and have been waiting
| for good weather to install them.
|
| While they weigh more than regular tires, they weigh less than
| the combined weight of regular tires + pump + patch kit, so it's
| a net win on weight.
|
| For me, the biggest win is not about not worrying whether or not
| I get a flat, it's not having to pump the darn things up week in
| and week out before going out on my (admittedly city commuter)
| rides.
| c0nsumer wrote:
| The pump and patch kit are effectively static weight on a bike.
|
| What's referred to as rotating mass on a bike (usually talking
| about wheels+tires) is noticeable. Maybe not as much on your
| city bike, but the thing that usually makes a bike feel heavy
| is the weight of the wheels, not the overall bike itself.
|
| Best of luck with them.
| ubermonkey wrote:
| I can see these working for commuters, but being WAY less
| interesting for roadies where speed and acceleration are
| paramount.
| [deleted]
| tzs wrote:
| > While they weigh more than regular tires, they weigh less
| than the combined weight of regular tires + pump + patch kit,
| so it's a net win on weight.
|
| Larger moment of inertia, though, so not a complete win. I
| wonder how the trade off works--where is the breakeven point
| between trading tire mass for mass being carried in a fixed
| position on the frame?
| gameswithgo wrote:
| I have done the math, and the inertia issue is basically a
| non issue. Humans don't accelerate hard enough to have any
| significant impact.
|
| the issue with airless tires though is bot weight, but
| rolling resistance and handling. Both are much worse. It is
| going to feel horrible.
| stickmangallows wrote:
| I love my Tannus tires. I spent a lot of time and money fixing
| flats from puncture vine (goatheads) on my road bike before
| getting them. I don't feel like it added much bad weight
| because they are so narrow, unlike my airless mountain bike
| tires. Well worth it.
| ndsipa_pomu wrote:
| The biggest problem with airless tyres is that bumps on the
| road cause localised pressure changes whilst pneumatic tyres
| distribute those pressure changes around the wheel. In practise
| this means that you feel more of the bumps and for big potholes
| you can end up damaging the rim. There's also the problem of
| energy loss as part of the tyre is compressed - with pneumatic
| tyres you only really have the outside of the tyre that is
| deforming and so they have less rolling resistance.
|
| When I tried airless tyres (a long time ago though) the ride
| felt very "dead" and I haven't bothered with them since.
|
| Tubeless however - that's the best ride performance that I've
| tried and you very rarely get punctures that the sealant
| doesn't fix.
|
| The actual weight of the tyres won't make a huge amount of
| difference (i.e. the rotational mass) as it only really affects
| accelerating which is much less common than simply maintaining
| your speed.
| etcet wrote:
| The weight of your tires is in the worst place for rotational
| mass. You'll definitely feel it if you're doing city riding
| between frequent red lights but it could arguably be a benefit
| if you're cruising for long distances as it'll act like a fly
| wheel to some extent.
| FpUser wrote:
| Why spend $20 when you can spend many times more for the product
| without any real benefits.
|
| "Polyurethanium" - when normal tire wears off you just replace
| single piece of rubber, when this adamantium dies one will have
| to replace that whole metal wonder.
| dylan604 wrote:
| How do you "replace single piece of rubber"? I've either had to
| replace a tube, or replace the tire itself. How is this
| different?
| FpUser wrote:
| Yes on a regular bike you replace cheap (sometimes not) tire.
| With this contraption they put tire / protective layer on top
| of their metal wonder. Problem is that this protective layer
| will wear in no time and then you will have to replace the
| whole metal piece which is expensive proposition.
| mbreese wrote:
| If you want background on the material in question here
| (nitinol), The Verge had a good video explainer about the
| material and a bit about how the "space tire" aspect will work.
| It's really a fascinating video of you've never seen the metal in
| action. I can see why it would be chosen for the environment on
| Mars. I'm not sure if it would be better than air tires on Earth,
| but for the low atmosphere environment on Mars, it makes more
| sense.
|
| https://www.theverge.com/2021/3/17/22334611/nitinol-metal-sh...
|
| https://youtu.be/Pn-6bGORy0U
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(page generated 2021-03-18 23:02 UTC)