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Showing content with the highest reputation on 10/29/20 in all areas

  1. There are two types of fluid flows in aero/hydrodynamics, compressible and incompressible. They can both be modelled by little springs between each fluid particle; when you push against one particle, it pushes against the next via the little interconnecting springs, and the fluid, in effect, compresses. If you push too fast, the little springs reach maximum compression, and the particles begin to 'pile up' into a bow wave. For air, this happens at Mach 1, and the air effectively becomes incompressible. Water is nearly incompressible from the get-go ( also, liquids and solids have transverse 'sound' waves as well as longitudinal ). That's why you see a bow wave on a boat doing 10 mph. That wave is the 'shock' of the particles bunching up because they can't move out of the way fast enough. Another ( huge ) problem would be cavitation. This is usually seen in pumps/propellers where the fluid can't flow fast enough into the area behind the pump/propeller blades, creating a low pressure area ( or even vacuum ) which tends to destroy equipment. For a plane the shock is the separation where supersonic air is drastically decelerated to subsonic ( inside the shock cone ), and it carries a lot of momentum/energy which is dissipated in the 'sonic boom'. If the 'sub' was at a shallow depth, with the surface close by, the spray pattern of the water shock into the air would be extremely interesting. to say the least. So the shock wave of travelling through water would be no different than through an incompressible fluid such as supersonic air, except for the cavitation problem, which I didn't consider on Sunday ( and which may make this idea a non-starter ).
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  2. Perhaps it’s because that’s not what the model proposes. You’ve even linked to pages that discuss the creation of particles Not what physics claims. Perhaps you could link to the statement (and its support) and not the author’s wikipedia page
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  3. Me The first PC (if you can call it that) I ever owned was a Commodore C16, featuring...wait for it...16kb of RAM. Yes, that's kilobytes. Taught myself BASIC back then...later I progressed to a ZX Sinclair, then to an Atari ST, where I taught myself C, MODULA-2, PASCAL, Assembler, and Lisp. Very nostalgic memories of spending days and nights trying to implement things that programmers nowadays would only laugh at! Was a great time, though.
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  4. You’re not looking for utopia. You’re looking for justification for your random religious beliefs. Religions have been around for thousands of years. If they were the path to utopia, one would expect us to be much closer to it by now.
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  5. You can buy solar laptop chargers, usually having some kind of battery included, that charge DC directly. I'm sure simple solar plus small "camping" inverter to local AC voltage/frequency is possible using standard plug in chargers. Having solar built in - back of fold out screen - would likely work too, but more for placing in sun when not in use, with more time like that than in use. It would not work so well during use.
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  6. One question only... Is the solar power for recharging the battery only, or do you want to run off it as well? -If you intend to run off solar, I assume you'll spend a lot of time outdoors. ; you're going to need a very bright screen. -You might wanna give yourself a little more than a month, as companies like Lenovo and Apple, with much higher development budgets than you, still haven't been able to accomplish this. -This pretty well limits you to very low power chips, based on the ARM architecture ( think Raspberry Pi and Arduino SoC ); you certainly can't use X86 architecture ( not even Atom ). -You would want the solar panel to have optimum orientation to the Sun; that would be screen/keyboard areas on a standard laptop form factor, so not particularly suitable. Even optimally, a 1/2 square foot ( 6 x12 inch, fairly large ) panel will produce a peak ( instantaneous ) of slightly better than 7 Watts. If solar is intended for recharging only, will you be using it only at night and re-charging during the day ? ( maybe this is the reason Lenovo or Apple aren't developing such an impractical product )
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  7. Along those same lines, many people don't realize that those beautiful pictures of nebulae, like the Orion nebula, are not something that a person could see no matter their location in space. Even if you were relatively close to the Orion nebula it would just look like a diffuse haziness in the night sky. Time lapsed and stacking of images makes the really nice pictures.
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  8. It's the age of the righteously indignant, it's far more nuanced than alternative facts... 🤒
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  9. The shock wave in water would be an interesting phenomenon. A problem with streamlining a submarine hull is that it's not the best shape for a pressure hull. Keeping out pressures above atmosphere are a priority for submarines, whereas planes never have to deal with a static difference greater than 1 atm, usually it's even less, and when it's an issue it's about keeping air in rather than being crushed. An autonomous or remotely-piloted vehicle would be required.
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  10. The XKCD one? https://what-if.xkcd.com/1/
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  11. Here’s the funny part. Humans ARE apes.
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  12. It might be friendly though and I want to give it a hug.
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  13. As a Christian I am to say no. God has that planned for us in the afterlife. Plus as that guy or she or she he said people have different views on utopia ,but can narrow down to the desires of the body, food and water for everyone , maybe AI women who look like models for brothels for sexual desires , maybe virtual world very realistic and it stimulates the mind, exercise for the body, maybe science can HELP in building a realistic uptopia , but through thinking I don't think that will happen, too muxh damage already and it is like snowball gathering snow falling down hill the future is that snow ball God bless homie
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