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Joined 3 years ago
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Cake day: June 26th, 2023

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  • Rough surfaces can be more aerodynamic than smooth ones

    “For more than 80 years, the principle of “the surface of an object must be smooth” has been the basic premise of aeronautical engineering throughout the world in order to suppress the transition to turbulence and reduce aerodynamic drag. This premise was based on the results of a 1940 study by Ichiro Tani, a Japanese aerodynamicist who quantitatively demonstrated the relationship between “surface roughness” (an indicator of the state of the machined surface) and turbulent transition, arguing that surface roughness, which was unavoidable with the manufacturing technology of the time, prevented laminar flow from being realized.

    However, in 1989 Tani reinterpreted the experimental data on rough-surface pipes obtained by fluid engineer Johann Nikulase in the 1930s, bringing a new perspective that “roughness may not necessarily only promote turbulent transition and increase fluid resistance.” Inheriting this idea, a research group led by Yasuaki Kohama of Tohoku University experimentally demonstrated in the 1990s that fibrous rough surfaces, which have fine fibrous irregularities on their surface, have the effect of delaying transition under certain conditions.”





  • You’re half right. The way companies expect people to use passwords is unsustainable. People can remember a password. No one can remember a unique, hard-to-guess password for every login they have. So they re-use passwords. Password re-use is so common and unavoidable that losing a single password is disastrous. It should not be. This is one of the promises of FIDO and passkey, not relying on a password that can be stolen, guessed and re-used.


  • xylogx@lemmy.worldtoComic Strips@lemmy.world5.9/10
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    2 months ago

    IMDB reflects popular opinion. Everyone has unpopular opinions, heck I liked the Emoji movie. Also, for some niche movies the ratings are wildly skewed since only die hard fans are voting on them. And for some movies where there are strongly held opinions, many people will pile-on and vote on them without even having seen the movie.

    All that said, IMDB is a useful tool for getting read on popular opinion on movies. Also, IMDB is standing behind me with a gun to my head. Send help, please.