UmbralRaptor changed the topic of #kspacademia to: https://gist.github.com/pdn4kd/164b9b85435d87afbec0c3a7e69d3e6d | Dogs are cats. Spiders are cat interferometers. | Космизм сегодня! | Document well, for tomorrow you may get mauled by a ネコバス. | <UmbralRaptor> … one of the other grad students just compared me to nomal O_o | <ferram4> I shall beat my problems to death with an engineer.
<SnoopJeDi>
Absolutely fantastic game
<SnoopJeDi>
Forgot how great the music is!
* UmbralRaptor
recalls a midi version of In the Hall of the Mountain King.
<kmath>
<ibogost> You go to Chick-fil-A, they serve you chicken. At Burger King, you get burgers. Taco Bell offers tacos. But at Panda Express... no panda.
<Ellied>
4-pin firewire connectors are borked. Why do they have that split down the bottom side of the jacket that makes the metal relax and prevents you from plugging it in unless you wiggle it just so?
<SnoopJeDi>
ooh, and Treasure MathStorm! I played an awful lot of that.
<egg>
!u ?
<Qboid>
U+1F4D5 CLOSED BOOK (?)
<SnoopJeDi>
I thought it was appropriate, egg
<egg>
indeed
<egg>
!wpn UmbralRaptor
* Qboid
gives UmbralRaptor a diffeomorphism
<egg>
!wpn SnoopJeDi
* Qboid
gives SnoopJeDi an antidisambiguated ORBAT
<egg>
!wpn bofh
* Qboid
gives bofh a BS 6008 ⚠
<egg>
!wpn Ellied
* Qboid
gives Ellied a sharp cathode ray tube
<SnoopJeDi>
!wpn egg
* Qboid
gives egg an alleged neutron anaconda
<UmbralRaptor>
!wpn egg
* Qboid
gives egg a Müller paraboloid
<UmbralRaptor>
!wpn -add:adj Soviet
<Qboid>
UmbralRaptor: Adjective already added!
<SnoopJeDi>
...and here I am at 6:21 PM on a Friday night watching "YungFlyyGaming" play part of my childhood
<UmbralRaptor>
(This means that there's a nonzero chance of getting a Soviet ORBAT)
<SnoopJeDi>
!wpn -add:adj Молния
<Qboid>
SnoopJeDi: Adjective added!
<egg>
huh why was it not there already
<SnoopJeDi>
Indeed!
<UmbralRaptor>
hm
<egg>
maybe it was in lowercase?
<SnoopJeDi>
list is a valid predicate, right?
<SnoopJeDi>
!wpn -list
* Qboid
gives -list a giant lamp
<egg>
SnoopJeDi: not for wpn
<egg>
should ask TheKosmonaut
<egg>
um
<egg>
Thomas:
* egg
pets UmbralRaptor with Лидов–古在
* UmbralRaptor
feels anxious
<UmbralRaptor>
!wpn -add:adj Лидов
<Qboid>
UmbralRaptor: Adjective already added!
<UmbralRaptor>
!wpn -add:adj 古在
<Qboid>
UmbralRaptor: Adjective already added!
<bofh>
grr, it's annoyingly hard to turn Gold into Lead. Okay, you can do it via neutron bombardment but I don't think hitting it with carbon nuclei works, the capture cross-section is too small and you're going to make either At-209... actually that's not too bad, you get Po-209 via \Beta^{-} decay from that (with a minor contribution of Bi-205) and after 125 years Pb-205 from the Po-209 via \alpha decay.
* UmbralRaptor
feels like context is missing.
<SnoopJeDi>
Knowing bofh such as I do I assume he means literal alchemy
<UmbralRaptor>
This expansion pack for Opus Magnum is wild.
<bofh>
I'm still amused that it's fairly easy to convert Mercury to Gold *if* you can enrich Mercury-196.
<SnoopJeDi>
bofh, spallation neutrons in a reflector geometry?
<SnoopJeDi>
let me just send you the MCNPX files for our ADS core ?
<bofh>
Since you can just bombard that with spallation neutrons (heck, even relatively slow neutrons suffice) to Hg-197 which decays to Au-197 (the only stable gold isotope) in about 2.5 days.
<bofh>
Problem is Hg-196, while stable, has an abundance of like 0.15%
<SnoopJeDi>
uh oh, I just opened an arxiv tab about triton bombardment of gold and the neutron σ
<bofh>
SnoopJeDi: and more like the inverse of alchemy, since I'm turning gold into lead (the context was seeing https://twitter.com/rygorous/status/934192014899363842 and realizing that lead and tin are actually more useful for short-term infrastructure rebuilds than gold, was wondering if I could do inverse-alchemy "easily")
<kmath>
<rygorous> Before you snark about that news item about doomsday preppers switching from gold to bitcoin, consider for a second… https://t.co/b7612eVZRS
<SnoopJeDi>
eh, anti-alchemy *is* alchemy as I see it :P
<SnoopJeDi>
(does that mean alchemy is a Majorana process?)
<bofh>
(LOL okay yes it is)
<UmbralRaptor>
pfft
<SnoopJeDi>
bofh, I identify so strongly with that thread. I listen to Fox most mornings (probably against my better judgement), and the gold commercials always tweak my inner prepper
<bofh>
and like, this isn't 100% impractical: you can already economically make Ruthenium from Molybdenum via slow-neutron capture Mo-100 -> Mo-101, Mo-101 decaying to Tc-101 after ~14mins, which decays to Ru-101 after another ~14mins.
<SnoopJeDi>
"it's gold you can carry in your wallet, so you always have something to trade?"
<SnoopJeDi>
look here laddie, if there's still a market for trading gold, it ain't the apocalypse
<bofh>
But this is made easy by Mo-100 being ~9.6% of mole fraction of stable natural Mo, as opposed to Hg-196 being ~0.15% mole fraction of the same.
<bofh>
rofl yep
<SnoopJeDi>
I really loved that thread about "we should move away from coal because it's apocalypse-insurance"
<bofh>
(also given how much the price of fucking Ruthenium has gone up lately, some of the chem labs might actually need to start doing that)
<SnoopJeDi>
from some months ago
<bofh>
(folks buy your Grubbs' Catalysts *now*, they're only going to get more expensive)
<SnoopJeDi>
bofh, yea, the main angle on our ADS pot is Mo-99 production
<bofh>
Like, I'll honestly take any reason to move further away from coal tbh.
<SnoopJeDi>
since a smallish cyclotron is a much smaller footprint than a breeder reactor and considerably less proliferationy
<SnoopJeDi>
also, same.
<bofh>
True, that it is.
<egg>
!wpn UmbralRaptor
* Qboid
gives UmbralRaptor a feline pin
<egg>
!wpn bofh
* Qboid
gives bofh an affine cotter pin
<egg>
pins!
* UmbralRaptor
is not too worried about proliferation, even if the US is the sort of country that would do a nuclear first strike.
<SnoopJeDi>
it's just less red-tape, which means it's actually a plausible model for medical isotopes
<SnoopJeDi>
we certainly aren't going to plop a breeder reactor down near every major hospital
<SnoopJeDi>
but it's well within the realm of imagination that facilities who do a lot of imaging would be able to produce for themselves on-site. All the machinery is already there since accelerators *already* run in hospitals
<bofh>
Wait, really? I would imagine a cyclotron would necessitate nontrivial surface area of land for it.
<SnoopJeDi>
my take is you'd likely just build a facility in major cities where it's called for, so I'm being a *little* disingenuous
<SnoopJeDi>
but like, cryo is already a problem hospitals have to deal with, so that one comes basically for free!
<bofh>
Again, assuming you have the space.
<SnoopJeDi>
power systems and all that yea, but they're tractable problems rather than "HAHAHAHAHAHAHAHAHA" problems
<bofh>
Granted, USA, so it might be feasible. And yeah. Agreed there.
<SnoopJeDi>
our K500/K150 "only" take up about a city block's worth of space
<SnoopJeDi>
and a lot of that is office space
<SnoopJeDi>
the 100 MeV design has a spatial footprint of 10 m, so yea you're well within striking distance of "it's in the basement"
<SnoopJeDi>
...of course, doing anything with that beam requires a Bunch of Other Stuff, so probably a dedicated production/distribution facility, yea
<bofh>
Huh, that's literally an order of magnitude smaller than I thought.
<SnoopJeDi>
yea even conventional machines are rather compact
<SnoopJeDi>
it's really easy to get lose in the numbers with accelerators, heh. particularly when LHC and gen3/4 storage rings are the major ones people talk about often (vs. linacs, FELs, cyclotrons, synchrotrons...)
<SnoopJeDi>
Hah, I'd never noticed the very conspicuous foil box visible in that photo
<egg>
awang: so btw, that stack overflow uncovered a really interesting bug in our integrator :D
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<whitequark>
SnoopJeDi: LOL FOIL BOX
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<egg>
the proximate cause was daftly recursive downsampling overflowing the stack when it didn't downsample much, but the reason it didn't downsample was that the velocity was inconsistent with the positions after going through a singularity
<SnoopJeDi>
probably the last thing people would expect most fundamental science to be based on
<egg>
that's because we stupidly kept the velocity *by incrementing it with Adams-Moulton of the accelerations* on an integrator that conjugate-symplectically gives you the positions
<egg>
this is daft :-p
<SnoopJeDi>
I'm fairly sure that a grad student spun a tale about how they bought all the foil in a store for some condensed matter lab, but it doesn't seem very true :P
<SnoopJeDi>
er, when I came here for my prospective visit that is
<egg>
!wpn whitequark
* Qboid
gives whitequark a tempered botfly
<bofh>
SnoopJeDi: rofl, the foil box is amazing
<bofh>
SnoopJeDi: and yeah, most of my mental idea of cyclotrons is recent-gen storage rings for i.e. Fermilab
<SnoopJeDi>
bofh, I shared the reply letter from SLAC to an "ugly architecture" columnist who suggested they could make better use of space by folding it up on several floors, right?
<bofh>
SnoopJeDi: not that I recall, link?
<SnoopJeDi>
will see if I can dredge it up with Twitter's godawful search
<kmath>
<SLAClab> #tbt 1987 Our historic 2-mile-long linac was runner up in @mercnews “Ugly Building Contest” for being “too long” https://t.co/6op4xuopwL
<SnoopJeDi>
"We will communicate this comment to the electrons."
<SnoopJeDi>
"... informational analysis adopts a somewhat purist mathematical viewpoint, whereby BLITs are considered to encode Gödelian "spoilers", implicit programs which the human equipment cannot safely run."
* Qboid
gives FluffyFoxeh a holomorphic pentode-like refractor
<egg>
!wpn SnoopJeDi
* Qboid
gives SnoopJeDi an alpha demi-culverin
<egg>
!wpn SnoopJeDi
* Qboid
gives SnoopJeDi an invisible inverter which vaguely resembles a delta function
<egg>
uh
<egg>
!wpn Snoozee
* Qboid
gives Snoozee a hatpin
<egg>
!wpn UmbralRaptor
* Qboid
gives UmbralRaptor a pythonic alternator
<egg>
!wpn whitequark
* Qboid
gives whitequark a term
<egg>
!wpn bofh
* Qboid
gives bofh a Trojan prediction
<egg>
Ellied: on your recent tweets, there's the case where you need a gender for grammatical purposes, because of some non-english languages; arbitrary strings are essentially unusable there http://site.icu-project.org/design/formatting/select
<egg>
Ellied: though tbh depending on select leads to combinatorial explosion of the work required of translators, so it's a bad idea in the first place
<egg>
Ellied: this requires the people writing the english strings to know what can't feasibly be translated from english though, which can be tricky
<egg>
it's probably the best solution for everyone involved, but it involves surprising constraints on what you can write
<kmath>
<minouette> When people notice Schroedinger’s Cat, I love pointing out it’s thermochromic and that Cat and poison disappear whe… https://t.co/ToFAtZJp7M
<egg>
UmbralRaptor: (because went, which I'll translate to passé composé, "es allé" (or "êtes allé" if I'm being formal), and because the verb is être, allé becomes allée in the feminine)
<egg>
UmbralRaptor: I mean I could use passé simple (allas, or allâtes) but then I sound like I'm recounting the epic of the raptor, not talking normally
<UmbralRaptor>
heh
<egg>
UmbralRaptor: you should go to ANBO though :-p
<UmbralRaptor>
To do: figure out a reason to go to Normandy?
<egg>
UmbralRaptor: petting cats is a reason right,
<UmbralRaptor>
:D
<soundnfury>
UmbralRaptor: only if you also call your LAN ports ð0, ð1 &c. ;)
<soundnfury>
!wpn UmbralRaptor
* Qboid
gives UmbralRaptor a Grothendieck detector
<UmbralRaptor>
soundnfury: time to submit a pull request!
<UmbralRaptor>
The Grothendieck detector cannot find examples.
<soundnfury>
I'd've thought that it would beep whenever pointed at any mathematical object
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<UmbralRaptor>
!wpn ferram4
* Qboid
gives ferram4 a bismuth Penrose eraser
<bofh>
soundnfury: or maybe any prime, but it always claims numbers of the form 3^k * 19^l, k, l >= 1 are prime too? :P
<bofh>
or maybe it *only* claims those are primes? :P
<UmbralRaptor>
;8ball Is this is like explaining factorials as a special case of the gamma function?
<kmath>
UmbralRaptor: Outlook not so good
<UmbralRaptor>
egg: that's the entirety of the question in Goldstein.
<egg>
UmbralRaptor: so I'm going to assume this is a time-dependent rotation, since there are time-dependent Euler angles (I see derivatives of the angles)
<egg>
UmbralRaptor: so you have the following functions: time -> Euler angles -> rotation in SO(3)
<egg>
UmbralRaptor: now, the time derivative of the rotation is an element of the Lie algebra ??(3)
<egg>
it's the angular velocity
<egg>
UmbralRaptor: and they ask you to express this derivative from the Euler angles and their derivatives
<egg>
this is at least conceptually what is happening here
<egg>
UmbralRaptor: do you know how angular velocities can be seen as antisymmetric matrices?
<egg>
!wpn UmbralRaptor
* Qboid
gives UmbralRaptor an ovoid hammer-like phototransistor
<UmbralRaptor>
soundnfury: why Hamiltonians use such intuitive letters.
<UmbralRaptor>
<egg> Henergy is a function of quosition and pomentum
<soundnfury>
:)
<UmbralRaptor>
*qosition
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<soundnfury>
*inquisition
ferram4 has quit [Read error: Connection reset by peer]
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<awang>
egg: Could you explain the "kept the velocity by incrementing it with Adams-Moulton of the accelerations on an integrator that conjugate-symplectically gives you the positions"?
<bofh>
I like how it's specifically *conjugate*-symplectic, not symplectic.
<soundnfury>
awang: it's very simple. A wizard did it.
* UmbralRaptor
? Euler, and gives up for the day.
<UmbralRaptor>
Now for export control training.
* UmbralRaptor
is reminded that he has consulted with Russians for rocket control algorithms.
<UmbralRaptor>
Whee, ITAR is mentioned.
<UmbralRaptor>
"There is no point in trying to regulate something that anyone can access." I have bad news for you about many things, narrator.
<bofh>
So I agree there's no point. People try, but there's still no damn point
<UmbralRaptor>
This example of an export controlled conference table P's amusing, though.
* UmbralRaptor
hopes eggsoplanets count as fundamental research.
<UmbralRaptor>
"even selling pencils to Iran is prohibited."