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Cake day: August 4th, 2023

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  • You have to search using language that papers might actually use though. “Parachute effectiveness” means what the satirical paper is exploring, whether it prevents death or not. The only serious studies that might have used that language would be old WW2 studies that threw people out of planes with different parachutes to see how many survived.

    If you want to know how to design an effective parachute, you should be looking at reference books like Parachute Recovery Systems instead.



  • Billion dollar costs aren’t rounding errors even at YouTube/Google’s scale. They’re a measurable percentage of total revenue. I agree that it slightly improves the user experience, it’s hard to imagine a worse cost/benefit tradeoff from an engineering perspective even at more realistic costs. It’s especially hard to justify when there’s an easy alternative for users in the form of downloading videos.







  • AlotOfReading@lemmy.worldtoxkcd@lemmy.worldxkcd #2948: Electric vs Gas
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    5 months ago

    Just did a quick eBay check. The cheapest 350hp ICE I could find was a rebuilt $3,000 Chevy engine. A new one is more like $6-8k. An equally powerful, brand new Siemens motor was $1,500.

    This makes sense when you think about it though. An electric motor is basically just steel with a bunch of coiled wire with some control electronics. An ICE is hundreds of pounds of precision cast and machined metal. The cost driver in electric vehicles is not the motor, it’s the batteries.



  • There’s probably a bunch of reasons for the multi wing design, but the big one is going to be improving lift/carrying capacity without increasing the width.

    The most efficient wings for low speeds are glider wings: as long and thin as possible. That makes them inconvenient to pack and folding joints are weak points. The second wing adds lift, but also problems: it’s less efficient than a single wing of the combined length would be and the front wing makes the rear wing less efficient. The winglet improves the situation somewhat. Facing downward also improves maneuverability.


  • That’s not how RF works. For one thing, microwaves run at 2.4GHz, which means they can’t “see” physical features smaller than a few centimeters (to greatly oversimplify what’s going on). The miniscule bubbles simply aren’t a big factor.

    Rather, what’s happening is that the ceramic (probably the glaze if we’re honest) has a higher cross section and/or lower specific heat than the food, especially when it’s frozen. It absorbs more energy and heats up faster.

    I would also expect far fewer and smaller bubbles with industrial slip casting (“pouring into a mold”) than manual production.



  • AlotOfReading@lemmy.worldtoAndroid@lemmy.worldUSB-C
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    1 year ago

    Apple was one of the major contributors to the USB-C standard, including the physical connectors.

    The tongue design was used because it makes high speed a lot easier. If your traces are in the center of the connector, you can do a cutout of the PCB and mount a “dumb” connector housing for the socket. You can also have a ground plane right in the middle and use both sides for differential pairs, which is exactly what happened. It also means you don’t have to deal with the pain of high frequency signals leaving the board into the air like other connectors.

    But yes, don’t shove screwdrivers into your USB sockets either.