I think the point that is counter to yours is that we are nowhere near the fundamental limits of energy density for batteries. It's probable we are near a fundamental limit for LiPo, but the point is that battery tech improves by changing technologies/chemistries. BEVs couldn't exist at all when the best rechargeable battery tech was lead-acid, but were enabled by LiPo. Theres most likely a type of battery you can't even imagine that has yet to be invented that could store >10x or more energy than current LiPo per unit cost or mass.
Hobovision
joined 2 years ago
I don't think closing threads is a great idea or in keeping with how this all works. I think it'd be nice to be able to mute a thread as an individual, but by its nature these discussions are open and shared with many instances. If we close it on kbin.social, other kbin instances, lemmy instances, and even places like mastodon and pixelfed could keep discussing, if I understand activity pub correctly.
Dude what the hell? You posted publicly in a public comment thread and are mad when the person you're talking about responded? You know this could happen on reddit too right? Creators are people too, you absolute dick.
I'm seeing a lot of misconceptions in the replies. You have it mainly right from a very high level.
The reason why prepreg "expires" is simply that the resin system is mixed before being impregnated into the fibers, so it starts the curing reaction immediately. These resin systems are usually designed to cure properly at high temperatures, typically 250-400F depending on end-use, but they'll still slowly react at lower temperatures. To further slow the reaction, prepreg is kept frozen. Prepreg also has two types of expirations: "shelf life" and "out life". Shelf life is how long it can last frozen. Out life is how long it can last at room temp.
Theres a few issues that can happen when using expired prepreg. It can be harder to laminate since it will be too stiff and not as sticky. It won't cure correctly causing failures in the resin.
Expired prepreg can be recertified by testing the material for those types of failures. Check if the prepreg can fold over a certain radius and stick to a certain angle without sliding off. Cure a sample and test it to see if cured properly.
PocketCasts was pretty much perfect for me for a long time and recently (past couple years maybe?) they did a big update which made it noticeably worse. I tried a few other apps and they had even bigger issues. I'm still using PocketCasts and they've fixed some of what they messed up but it isn't perfect.
They have a good library of podcasts built in but also allow you to add custom rss feeds for any smaller shows they don't have or if you have private feeds from patreon or elsewhere.
And we're already posting screenshots of reddit posts that are screenshots of tiktoks. Awesome
If we're talking approaching fundamental limits, Hydrogen fuel cell is not a great comparison. A high pressure tank can only get so light, even with linerless ultra high strength carbon fiber pressure vessels, the mass of the vessel is maybe 6-10x the mass of the hydrogen it carries. To increase specific energy there you need to go to cryogenics which is a whole technology leap and has its own set of challenges.
Battery tech has been improving more than you have seen, clearly. Since '08, lithium batteries have increased energy density by 8x (https://www.energy.gov/eere/vehicles/articles/fotw-1234-april-18-2022-volumetric-energy-density-lithium-ion-batteries). The best LiPo batteries are around 0.9MJ/kg right now, but there's no fundamental reason a battery couldn't achieve 9MJ/kg. Lithium-air batteries could theoretically achieve way higher energy density than that even (https://en.m.wikipedia.org/wiki/Lithium%E2%80%93air_battery), and have already been demonstrated in a lab to achieve more than 5x what current commercial automotive batteries are doing.