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Cake day: June 17th, 2023

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  • cynar@lemmy.worldtoSelfhosted@lemmy.worldServer for a boat
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    12 days ago

    Your best bet might be to use a laptop as the basis. They are already designed with power efficiency in mind, and you won’t need an external screen and keyboard for local problem solving.

    I would also consider having a raspberry pi 3 or similar as a companion. Services that must be up all the time run on the pi (e.g. network admin). The main computer only gets kicked out of sleep mode when required. The pi 3 needs less power than the newer pis, while still having enough computing power to not lag unless pushed hard.

    I definitely agree with SSDs. HDDs don’t do well when rotated when running. Boats are less than a stable platform.





  • cynar@lemmy.worldtoScience Memes@mander.xyzBLOOD IS BLOOD
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    16 days ago

    I have a relative who has an unfortunate condition that causes internal bleeding. They’ve had enough blood transfusions that their antibodies are completely haywire.

    Multiple times, doctors have not listened to their protests, and given them O-. They turn an impressive shade of yellow (among other, more serious, issues).

    Last I heard, there were 2 compatible donors known, 1 in a different country. Thankfully, you can store blood longer term. It’s just not cost efficient to do in bulk. They have their own little stockpile of blood at their local hospital (mostly self donated).


  • That method is still mostly recommended, though mostly for younger children/babies. The Heimlich maneuver is difficult to perform on a small body. You either over squeeze, and cause harm, or are too tentative, and so not helping.

    With babies, you hold them lying on your forearm, facing downwards, and slap (open handed) hard. I’ve only seen it used once, but it worked perfectly then.


  • The best bet is to let your local aviation authority know. They are generally the ones with the actual powers, as well as the knowledge to apply them.

    At least in the UK, the laws cover anything that leaves the ground under an open sky. There are exceptions for RC toys and drones, but they have limits. One of the limits is you cannot fly within a certain distance of anyone or anything not under your control.

    Basically, most places require your permission to fly over, or near to your land. If they are overflying, they are breaking the rules.

    It’s worth noting, depending on the size of the system, it can be difficult to judge distances. The ones I work with are large. We regularly have officials insisting we are massively out of our flight area. GPS logs show that it was well within the entire time.


  • There’s a story, though I’m not 100% sure on how true it was. Queen victoria did a royal visit to the new lab overseen by Michael Faraday. She asked him what use this new “electricity” was? His response was along the lines of "mam, we’re not completely sure, that’s why we are researching it.

    As for actual uses. It could give us the theoretical key to room temperature super conductors. It could give us a foundation for exotic space drives. It could help crack new forms of fusion reaction.

    Ultimately, it’s a foundational block. What gets built on there is hard to predict. By comparison, GPS is not an obvious extension of relativity. However, without an understanding of relativity, GPS would basically be useless. It would drift km/day


  • The limiting factor is the bend. The subatomic particles want to go in a straight line. A magnetic field is used to bend the beam around into a circle. The faster the particles are moving however, the more energy is needed to bend them. A larger circle has less bend. This lets you get your particles faster.

    Since E^2 = M^2 C^4 + P^2 C^2 (the full form is E=MC^2 ). If you can force the particle to stop rapidly, then you can force the energy from momentum into mass. This is done by hitting 2 beams into each other. The faster the beams, the more energy is available to convert to mass.

    Most of the time, this creates a lot of mundane particles. However, ever so often it creates something interesting. They rapidly decay into mundane particles, but the shower they create tells us a lot about them. The catch is that all the energy needs to be present at once. You can’t use more particles, you need to make them move faster.

    As for why. The more particles we have to study, the more we can figure out about the underlying rules. We have a number of theories. They all agree at lower energy levels, but disagree at higher energy levels. By knowing which is correct, we can pry deeper into the workings of reality.








  • A desert is a very different environment to “normal”. Nievly you would think solar would be better.

    Unfortunately:

    • A lot more sand means a lot more cleaning, one of the few ongoing costs of solar.

    • Sand is ablative. A sand storm will scratch and erode the surface of the panel. This will reduce its efficiency.

    • Sandstorms can darken the sky. A lot of direct light can be lost to a sandstorm.

    • Solar panels don’t work well when hot. Deserts are generally quite hot, when the sun is shining.

    • Solder joints don’t like thermal stresses. The panels, ultimately need wiring together. The joints (cell to cell, and cell to wire) don’t like thermal stresses. Deserts get cold at night, and hot during the day. A lot more panels than normal will be lost to failed electrical connections.

    Wind, on the other hand, does well in a large open area. The only additional effects of sand would be blade ablation, and sand in moving parts. Both of these are easier to counter.


  • cynar@lemmy.worldtoScience Memes@mander.xyzMoon dust
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    2 months ago

    It’s sand that has never been exposed to water or oxygen. This leaves various reactive chemicals on the surface that would normally be broken down. The lack of water also means the particles haven’t been smoothed off as much. They are sharp and spiky.

    The combination of these effects makes the dust quite unique, compared to earth dust.