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Cake day: August 6th, 2024

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  • glorkon@lemmy.worldtoScience Memes@mander.xyz*Permanently Deleted*
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    3 months ago

    Let’s do it:

    The phenomenon that causes divers to be trapped is called differential pressure, or Delta P. It requires surprisingly little Delta P to trap divers in such a way that they can’t free themselves.

    The formula is simple: F=Δp⋅A

    Δp = Differential pressure, A = the area the differential pressure acts on, in our case the cross sectional area of the pipe.

    Example:

    30 cm pipe => A = π⋅(0,15)² m²

    Delta P only (!!!) 0.1 bar (= 10 kPa).

    F = 10,000 Pa ⋅ 0.07 m² ≈ 700 N. This equals roughly 71 kg of weight.

    Now, let’s try this with the numbers above. Unfortunately, we don’t know the diameter of the pipe so let’s again assume 30 cm:

    Δp = 21.375 - 14.7 psi = 6.675 psi ≈ 0.46 bar = 46 kPA

    F = 46,000 Pa ⋅ 0.07 m² ≈ 3250 N.

    => You would be sucked to this pipe opening with a force of roughly 330 kg. In other words, you’re fucked.

    For fun, let’s assume a 50 cm diameter pipe:

    F = 46,000 Pa ⋅ 0.196 m² ≈ 9020 N.

    This equals roughly 920 kg of weight.

    => There is absolutely no escape here and I think it’s safe to assume the diver would be sucked through that pipe.

    And finally, to answer your question (I’ll skip the math here), a 10 cm diameter pipe with the same Delta P would mean 37 kg of weight. I think it would be possible to escape in this scenario, but it’ll not be effortless.










  • Oh, there can be all kinds of uses.

    For example, I own an LTO tape drive. Unfortunately, I couldn’t get the IBM drivers to compile on my particular flavor of Linux, but I do have a dual boot system.

    Now, Windows is a shitty, shitty OS that I only boot up when I really need to. It interferes with all kinds of stuff in ways I hate, for example - copying files. It just refuses to read large files in a continuous, reliable data stream without any interruptions from my SSD when backing them up to tape. This causes the LTO drive to slow down, speed up, rewind, which is not a good thing because it causes additional wear on the tape.

    Fix: Create a large RAM drive, copy files to RAM drive, run backup with RAM drive as source.



  • Actually, today’s Germany is quite happy to take anyone with some sort of qualification, no matter your family tree. If you are Jewish or not, that won’t really make a difference to immigration requirements, as far as I know.

    However, there is quite a bit of antisemitism going on in the Muslim communities, I’m afraid. As a German I’m really proud that our country is so open and welcoming to refugees and immigrants, but unfortunately people don’t just drop all of their own prejudices when crossing the border.

    Also, the rise of the extremist AfD party is a very worrying development. These Nazi thugs basically want to copy Trump’s policies and they also want Germany to leave the EU. If they somehow get voted into power, you would definitely regret having moved here.