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.
<bofh>
Yeah see I have somewhat bad essential tremor that's inexplicably *particularly* bad when soldering, so that's a lot of why I hate hand-soldering SMD.
<Ellied>
totally fair
<Ellied>
that'll be me someday
<Ellied>
my hands already shake if I haven't had enough food, or have got my caffeine/venlafaxine/bupropion balance wrong
<UmbralRaptor>
"Kollar-Kotelly [presiding judge] said in her opinion that the president’s directives are “not genuinely based on legitimate concerns regarding military effectiveness or budget constraints, but are instead driven by a desire to express disapproval of transgender people generally.”"
<bofh>
Well, the judge is kind of, erm, exactly correct there.
APlayer has joined #kspacademia
<UmbralRaptor>
It's still nice to get an official confirmation
icefire has quit [Read error: Connection reset by peer]
<kmath>
<paullicino> PLEASE check your children's candy VERY CAREFULLY this Halloween. I found an M4A3E8 Sherman tank in this box of Poc… https://t.co/Lo6gjAWc6c
<UmbralRaptor>
pffft
<Iskierka>
I think this person wins the race
<Ellied>
at least till someone manages to stage one of those with an actual nuclear warhead
<Iskierka>
... is there a museum with a replica tsar bomb?
<UmbralRaptor>
Not that I'm aware of, but Air&Space has at least 2 ICBMs. Also there's that nuclear museum in Albuquerque.
<kmath>
<bofh453> Ahh yes, eXtremely Large Magnetoresistance (XMR). Not to be confused with Giant MR (GMR), Colossal MR (CMR) or Extr… https://t.co/1f5OaFHoga
<UmbralRaptor>
"When M>>m, the reduced mass is approximately equal to m. Sometimes it is assumed that m = {\displaystyle \mu }. In the case of the planet Mercury this simplification introduces an error more than twice as large as the relativistic effect."
Iskierka has quit [Ping timeout: 198 seconds]
<egg|zzz|egg>
!wpn Fiora
* Qboid
gives Fiora a 22 AWG bad panzer which strongly resembles a bundle
<egg|zzz|egg>
!wpn UmbralRaptor
* Qboid
gives UmbralRaptor an abelian maser
<egg|zzz|egg>
!wpn bofh
* Qboid
gives bofh a 2N7000
Iskierka has joined #kspacademia
<Qboid>
APlayer: Ellied left a message for you in #kspacademia [30.10.2017 23:35:07]: "er, unless you're quite sure, you almost certainly do *not* want to buy something in the SOT-23 outline, that's like 2mm across and really hard to solder without a custom PCB with a pad to accept its shape and hot air station"
<Qboid>
APlayer: Ellied left a message for you in #kspacademia [30.10.2017 23:36:15]: "using SOT-23s on a solderless breadboard is basically impossible without first soldering them to a suitable breakout board, those things are *tiny*"
<APlayer>
!wpn everyone
<Qboid>
APlayer: Ellied left a message for you in #kspacademia [30.10.2017 23:38:33]: "That being said, those parts *do* look well-suited to the task, so if you are up for trying to mount such a small thing, they'd work. I think you'll find this is a common problem with component shopping; all the good stuff is microscopic. :P"
<APlayer>
Ellied: Uh, are the pins as short as they are in the picture?
<APlayer>
And what about the positive/negative voltages and currents?
<UmbralRaptor>
egg|work|egg: fine, I'll get off the ceiling.
<BPlayer>
!wpn egg
* Qboid
gives egg a pigeon-guided haloalkane
<UmbralRaptor>
e_14159: all hail cubehelix?
<egg|work|egg>
!seen rqou
<Qboid>
egg|work|egg: I last saw rqou on [30.10.2017 23:43:19] in #kspacademia saying: "solution: stop using breadboards :P"
<BPlayer>
!seen lamont
<Qboid>
BPlayer: I last saw lamont on [31.10.2017 06:42:56] in #RO saying: "steering and gravity losses don’t depend on the rotation of the planet below — think about an orbit over a spinning airless planet — so surfaceVelocity has to be incorrect"
<kmath>
<HazelCricket> @FakeUnicode on iOS, YouTube replies default to containing the other user's username https://t.co/xDkTzgjxzx
<BPlayer>
Uh, I asked in #kspofficial a while ago... Regarding rocket physics, if I use the equation s = 1/2 * a * t^2 + v * t and a changes in the process... May I just substitute a for F/ (m_0 - t * fuelConsumption)? UmbralRaptor said that it depends "on details", but he had to leave for a meeting. Anyone know what those details could be?
<SnoopJeDi>
That kinematic equation is predicated on the acceleration being constant, so the longer your time samples are, the worse an approximation it is.
<BPlayer>
Time samples?
<SnoopJeDi>
the interval over which you're pretending it is constant
<BPlayer>
Ah, wait, I think I have a flaw in my logic here
<SnoopJeDi>
the formula comes directly from integrating a(t) twice, with the assumption that a(t) = a_0
<BPlayer>
I am just substituting a(t) into the equation and assume the t on which a depends and the t already in the equation are the same
<SnoopJeDi>
right, that's not mathematically sound, because the formula itself is based on the assumption that a(t) is constant
<SnoopJeDi>
(this is why integrators exist)
<BPlayer>
So I need to integrate the formula indeed
<SnoopJeDi>
You're doing it anyway if you use a ballistic formula, you're just making assumptions which generally do not hold true
<BPlayer>
I am calculating a suicide burn with this. In particular, I wanted to start the burn when the burn duration was equal to the time to impact. The suicide burn happens in an atmosphere, and when I start it, I am moving at terminal velocity, so I assumed time to impact was altitude / velocity (since velocity would be nearly constant). However, this does not take into account that I am perfoming the suicide burn,
<BPlayer>
so the time to impact was off
<BPlayer>
Now I am trying to account for that this way
<kmath>
https://twitter.com/mcnees/status/925371446179876865 <mcnees> Hermite said of Weierstrass's construction: "I turn with terror and horror from this lamentable scourge of functions with no derivatives."
<SnoopJeDi>
Happy ℋalloween I guess :)
<BPlayer>
bofh: You're obliged to explain to me how Weierstrass' function works, now :P I've looked up and found that it is continuous but not differentiable. How does that work?
<SnoopJeDi>
it's got kinks everywhere
<BPlayer>
And how is it continuous in that case?
<SnoopJeDi>
in the same sense than f(x)=|x| is continuous but not differentiable at x=0
<BPlayer>
Okay, in what sense is |x| continuous at 0?
<kmath>
<scanlime> @TucoTheCat I think he just brought this down from the rafters https://t.co/fPqCuN9MNU
<BPlayer>
"a continuous function is a function for which sufficiently small changes in the input result in arbitrarily small changes in the output." I am currently thinking this
<kmath>
<scanlime> @TucoTheCat I think he just brought this down from the rafters https://t.co/fPqCuN9MNU
<bofh>
pretty much what egg|nomz|egg and SnoopJeDi said.
<SnoopJeDi>
BPlayer, another way to look at it is that continuity doesn't involve any "jumps"
<bofh>
(it's trivially continuous since it's the uniform limit of continuous functions)
<SnoopJeDi>
i.e. contrast |x| with the Heaviside function
<SnoopJeDi>
or 1/x or whatever
<egg|nomz|egg>
(unless there is a jump in the set from which you come of course)
<SnoopJeDi>
actually nevermind, 1/x is a bad example because of lack of a defined value
<egg|nomz|egg>
SnoopJeDi: yeah that's all very continuous on nonzero reals
<bofh>
1/x has a singularity at 0
<bofh>
I almost said "pole of order 1", but no, that's what 1/z has :P
* egg|nomz|egg
eggstends bofh to the complex plane
<bofh>
~*~ my home ~*~
<BPlayer>
Humm, yes
<BPlayer>
I think I get it
<BPlayer>
So Weierstrass' function has a sharp edge at every point?
<SnoopJeDi>
Correct
<bofh>
Indeed.
<Iskierka>
I assume this is just "can't differentiate to a continuous function"
<Iskierka>
as they do look like non-continuous functions would work fine
<BPlayer>
And how can an edge be at two neighbouring points? I mean, don't you need two lines to have an edge?
<egg|nomz|egg>
nope, not differentiable at all, Iskierka
<SnoopJeDi>
BPlayer, the original definition is a Fourier sum, so the lazy answer to that is "infinity is weird"
* BPlayer
shuts up
<SnoopJeDi>
I mean the answer is also "yes" you just have an infinite number of edges heh
<SnoopJeDi>
the images on the wiki article do a good job giving a quick view of it
<SnoopJeDi>
hah, the page for "Pathological (mathematics)" begins with ""Well behaved" redirects here. It is not to be confused with good behaviour."
<bofh>
ROFL
<BPlayer>
Ah, it is a fractal
<BPlayer>
That makes more sense to me
<bofh>
Also I love the "X (mathematics)" format.
<bofh>
(cf. "Pair of Pants (mathematics)")
<SnoopJeDi>
learning about the pants decomposition is the best thing I've gotten from A Capella Science
<egg|nomz|egg>
'<SnoopJeDi> BPlayer, another way to look at it is that continuity doesn't involve any "jumps"' << so unfortunately that doesn't actually work as a definition (even if we require the function to go between connected spaces), because https://en.wikipedia.org/wiki/Topologist%27s_sine_curve; you need the graph to be closed as well as connected
<SnoopJeDi>
that's why it wasn't presented as a definition egg|nomz|egg
<egg|nomz|egg>
I know
<egg|nomz|egg>
but it's a good idea to qualify these things with caveats
<BPlayer>
"Wikipedia does not have an article with this exact name. "
<SnoopJeDi>
pathological examples are for mathematicians ;P
<Ellied>
I guess it could be depletion mode or something but I'd expect them to make more of a big deal about that
<Ellied>
That N-channel one looks great; the P-channel one is *probably* fine but it looks like its gate threshold might be a little high.
<Ellied>
the maximum threshold is 4.0V; usually I'd be sure to clear the threshold by a bigger margin than that for a part that's seeing a lot of power
<Ellied>
no big deal if that's your best option, but I might shop around a little more
<bofh>
Fiora: the whole thing gets even more silly/insane when you realize Manafort was Victor Yanukovych's campaign manager before he was Tr*mp's.
<Ellied>
it should stay in the good ohmic region up to a little over 2A at 5V on the gate, which is enough for your purposes
<Ellied>
bofh: it's buried, in the very last interview log IIRC. If you haven't read that one through before, I recommend starting at the beginning; it's a great read.
<kmath>
<lx_rudis> sadly, all that remains of their culture are fragments; puzzling things such as this set of religious icons, no dou… https://t.co/MSjSCNSWct