ice9

@__ice9

I do quantitative things. Sometimes I think about society and economics.

Vrijeme pridruživanja: siječanj 2017.

Medijski sadržaj

  1. prije 6 sati
  2. 5. velj
    Odgovor korisniku/ci

    Arguably true, but only in theory. In practice, a number of other functional governments have shall-issue gun licensing. Moreover, I doubt there is much of a licensing process anywhere in the world with a weak rule of law, particularly in active conflict regions.

  3. 3. velj

    Apparently there may be significant numbers of free functioning mitochondria existing outside of cells in the bloodstream.

  4. 3. velj
    Odgovor korisnicima

    Hmm no, still seeing them.

  5. 30. sij

    Discussion of the proposed 'EARN IT' bill in Congress-- Another attempt to indirectly censor the Internet, set up tribunals on content quality, and reduce the use of strong encryption for messaging services run by media platform providers.

  6. 30. sij
  7. 29. sij
    Odgovor korisnicima i sljedećem broju korisnika:

    Was aluminum used on the basis that higher thermal conductivity for dumping heat to the coolant stream as rapidly as possible trumped the higher melting point but worse thermal conductivity of e.g. stainless? Then again, stainless still seems to be able to dissipate it--

  8. 29. sij
    Odgovor korisnicima i sljedećem broju korisnika:

    These oversized Schott flange reactors are more convenient than ordinary narrow necked flasks for chemically treating ceramic powders as well-- e.g. slip-casting can often produce stronger green forms if the material is acid-etched beforehand. Useful for containing volatiles.

  9. 29. sij
    Odgovor korisnicima

    C-type W-30Re in a tungsten sheath, but everything is so overwhelmingly radiative by then that emissivity vs thermal conductivity of the TC itself is an issue. Optical pyrometry is a better standard, but most pyrometers cap out below even S-type ceiling. Furnace interior like--

  10. 29. sij
    Odgovor korisnicima

    This is new information to me, and the result reported at the bottom here is rather astonishing. This reminds me of the much older known technique of slip-casting magnesia in alcohols instead of water. This is pressing-free...?

  11. 29. sij
    Odgovor korisnicima i sljedećem broju korisnika:

    A beautiful material. 3100 is above the melting point, though, even in Kelvin. Must be very reluctant to sinter. How did you contain the green forms? Powder bed of more B4C underneath? Did it take isostatic pressing?

  12. 29. sij
    Odgovor korisnicima

    So many flavors. Mind the NASA critical temperature range with CPSZ and never trust MSZ beyond 1000C in the long run. Oddly, YSZ doesn't care at all. The scandia kind is magical for Nernst elements, like SiC but for air, though it still needs preheat (less than YSZ).

  13. 29. sij
    Odgovor korisnicima i sljedećem broju korisnika:

    The physical evaporation of material from refractory metal heating elements can destroy them well below their melting points. This in turn can be greatly slowed by merely using argon shielding gas instead of a vacuum, or physically coating the element in e.g. thorium dioxide.

  14. 29. sij
    Odgovor korisnicima i sljedećem broju korisnika:

    At sufficiently elevated temperatures, oxygen becomes directly permeable through quartz glass, alumina, zirconia, and all other known oxide ceramics, making them increasingly useless as protective shielding for metals-- and conversely useful for solid oxide fuel cells.

  15. 27. sij
    Odgovor korisniku/ci

    Not sure about that per se, but I appreciated this excerpt--

  16. 27. sij
    Odgovor korisniku/ci
  17. 27. sij

    Much like "show more replies," it appears "hidden replies" has a convenient Streisand effect-- possibly an even stronger one, as it requires manual action by the author and only appears at all when such action has been taken.

  18. 27. sij

    Buried in this discussion of viable and non-viable regions in the state space of the dynamical system, there is an interesting point on the existence of conditions that will irretrievably result in a stall during autorotation.

  19. 27. sij
    Odgovor korisniku/ci

    The only places that still have an overpopulation issue are central Africa and parts of the Middle East. Literally: nowhere else in the world needs a lower fertility rate for societal, economic, or environmental sustainability.

  20. 24. sij

    The ancient Macedonians apparently had textile laminate armor, like a primitive sort of Kevlar vest--

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