Nat Schaeffer

https://nschaeff.bitbucket.io

Last Notes

2026-05-10 00:51:44 UTC

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which does not mean F is the smallest Lagrange number ?

2026-05-09 22:21:10 UTC

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sorry, I'm lost :
You say "the golden ratio has the smallest possible Lagrange number, namely √5", yet F > sqrt(5)...
And you also say, "F is a Lagrange number and F is the smallest with this property" (I understand 'this property' to be 'a lagrange number').
What did I misunderstand?

2025-09-08 19:42:38 UTC

A stably sratified layer can lead to magnetic field generation ! This is what we show in a new paper, accepted for publication :
https://arxiv.org/abs/2506.18521
#astrophysics
The stable layer is prone to double-diffusive unstability, which reconfigures the stable layer into 2 regions, one very stable, and one convective.

2025-01-15 21:10:29 UTC

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why is an infrared filter useful to reduce atmospheric turbulence ?

2025-01-09 09:49:48 UTC

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ok, I'm a bit disapointed because nobody seems to like liquid metals here!
While they are not plasmas they obey the MHD equations. They would lie somewhere near the P and Q of "Quantum Plasmas" or a little bit below.

2024-12-26 22:10:04 UTC

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it is because the fluid/plasma will respond to this force and move accordingly.
Then, the induction equation tells you that B is advected by the flow just as if it were material lines, and hence will evolve towards "straight lines".

2024-11-06 20:58:36 UTC

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try skred. No phone number or email needed. I find it easy to use.
Super secure, and not from the US.
https://www.skred.app

2024-10-29 19:57:31 UTC

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may I point out an obvious bias? Those who have knee problems do not bike so much, because ... of their knee problem.
Same for dose-response: you stop biking because of knee problems...

2024-08-02 12:43:01 UTC

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so my question is: what is the carbon intensity of solar power + 4-8 hours battery backup ?
Without battery backup it is already around 40 gCO2/kWh, which is 4x wind and 10x nuclear.

2024-08-02 08:25:19 UTC

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so you have 2 hours of solar power that can be stored on batteries ? How does that make a difference in:
1) satisfying power demand
2) carbon footprint of the whole system
For 1) it probably allows to use less fossils for the peak of daily demand.
For 2) it will have a negative impact at the fabrication level. Can 1) be enough to offset 2) completely? I don't know.
Anyway, 2h of battery backup does not help the seasonal problem at all...

2024-08-01 23:15:49 UTC

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What does "battery capacity to the tune of 10% of their maximum output" mean?
Battery capacity = energy (e.g. in Wh); power output is power (in W).
So is it 10% of annual energy output? Daily output? These are VERY different.
Solar electricity may be interesting because of a relatively low carbon footprint (although around 4x larger than wind and 10x larger than nuclear).
Adding batteries increases carbon footprint a lot.