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solrize

@ solrize @lemmy.ml

Posts
19
Comments
882
Joined
3 yr. ago

  • Scientists Build the First 3D Cloak That Makes Objects Invisible To Heat

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  • This sounds pretty neat. It sounds like it uses transformation optics, which I've just been reading about.

    You know how a lens bends light, i.e. a light ray enters the lens and travels at a different angle that depends on the lens's index of refraction? Now suppose the index of refraction changes continuously, like air's index of refraction changes with temperature. So if you have warm air near the ground that gets cooler with height, light can actually travel through it by a curved path. That's how mirages happen.

    Now suppose you can somehow control the index of refraction in a volume of material. So you can imagine an "invisibility cloak" where light coming in from behind you gets steered around you and comes out in front of you. People looking straight at you see the light from in back of you so it's like you're invisible. This doesn't seem technologically doable with visible light (at least for now) but it's been demonstrated in the lab at microwave frequencies, with small objects like a few centimeters. It's really cool how the math works.

    This sounds like they've done something similar with heat. They use a 3D printed heat sink with a special shape to make the temperature in front of something look like the temperature behind the thing, masking the heat source in the middle.

    If you look up "transformation optics" there's a lot of stuff about invisibility cloaks, maybe because there's military funding in the field and the army wants to make stuff invisible, lol. But the math and physics are interesting even if the applications are overstated. It turns out that the math used in studying how the materials curve light is similar to the math of general relativity, which is about how gravity bends light near stars and black holes. So that also leads to a bunch of breathless headlines about making black holes in the laboratory. It's not 100% bogus (they do get some cool effects) but yeah, of course it's an analogy, not an actual black hole.

    Here's a TED talk by one of the guys involved with this. I haven't watched it yet but maybe I will. I saw another youtube lecture by him and it was interesting. https://www.youtube.com/watch?v=v9d-EBgro50

  • What's something you know about philosophy?

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  • Time flies like an arrow. Fruit flies like an orange.

  • What's something you know about philosophy?

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  • I Regret Migrating to Codeberg

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  • I think a lot of Codeberg users are refugees from Github who didn't want Microsoft telling them what to do. Joke's on them, now they also don't want Codeberg telling them what to do. Self-hosting is the answer, but something like federation between self-hosted forges also seems like a good idea.

  • If the Fediverse became more popular, wouldn't it fall under the law's "Age Verifications" rules too?

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  • In one description I saw, part of the criterion was algorithmic feeds i.e. viewer manipulation. Lemmy has a fairly wimpy form of that compared to something like Facebook, and it could be shut off entirely without any loss. If it were up to me I'd shut it off either way.

  • Replacing a landline phone

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    1. I've had trouble getting Jami to work at all, I think because of incompatibilities between versions and whatever. You might have better luck with something like Linphone.
    2. I haven't tried a VOIP hardphone but I use Linphone on Android sometimes. I would say call quality is worse than normal cellular voice calls even those are certainly VOIP at some level too.
    3. VOIP is more crap to fool around with and periodically troubleshoot, but you can get it to work if you have to. I don't find landlines to be worth it any more (I just use mobile voice) but they're probably still the most reliable of the approaches, and I guess it depends somewhat on your family's discomfort level with technology.

    VOIP hardphones are nicer to use than mobiles, but I guess unlike traditional landlines, they don't work in power outages. All the ones I've seen rely on a power cube.

  • What's Your Ebook Automation Pipeline

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  • Epub is html with some crap wrapping it. Converting it to text follows the html formatting, like using the lynx browser.

  • What's Your Ebook Automation Pipeline

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  • Mostly pandoc (for epub to text) and a few stupid python scripts. I'm a luddite and prefer reading text files. I don't use any particular collection management beyond filenames and grep.

  • The inevitable "bias" when watching live chess – how do you handle it?

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  • It's fine, there's a whole industry trying to turn chess into a spectator sport based on the hopes that viewers will root for their favorite players and buy stuff from the advertisers, or whatever. Compared to competition level players I barely understand the game, but I still enjoy spectating. These days of course everyone roots for the evaluation bar.

  • What are some cute names for female vipers?

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  • There's a Harry Potter story where he had six pet basilisks called Madonna, Kip, Aqua, Marine, Delphi, and Sang. Maybe that's a start. He also had a gaboon viper named Kichaka. And there was a mention in a Roald Dahl book about using a viper for something, but "it must be a vindshield viper". That stayed with me even though I've forgotten the rest.

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    Why do so many no talent philensteins and crybabies choose to be apolitical?

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  • Or maybe Albert Einstein's layabout brother-in-law who couldn't even spell his own name.

  • The Email They Shouldn't Have Read

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  • This is like those AI slop youtube channels where they make up stories about celebrities with a suspicious lack of details. Sorry this needs names and specifics.

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    What do you think billionaires are preparing for?

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  • Pete Hegseth announces annual testosterone screenings for service members

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  • I thought TRT messes up your body's ability to produce testosterone naturally. Not good.

  • [Support] HDD diing or something else?

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  • Try smartctl -a on the drive (install smartmontools if needed), to see the error counts. Yeah, back up your stuff, which you should do anyway.

  • What do you do when you have a song stuck in your head?

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  • It's a sign that you're not sleeping enough. Catch some Z's.

  • money [problem or solution]

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  • One saying is that money can't buy happiness but it can definitely help relieve stress.

  • The Backlash Is So Strong That People With “Pervert Glasses” Are Afraid to Use Them in Public

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  • Being able to ruin a product presumes that it wasn't vile to begin with.

  • It's just C with two plus signs, how hard could it be?

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  • A garbage collector is just a monoid in the category of endofunctors, what's the problem?

  • Help choosing a good HDD for my home server?

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  • IDK really. I'm repeating what I saw someplace years ago. I would say do a real RAID if you manage it. Maybe RAID 5 on 3 drives.