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fragariavescana

oh god oh fuck a giant seems to be devouring the sun

fragariavescana

dw it's fixed now

raginrayguns

Thinking about a particle in a box bouncing back and forth...

in a complete cycle the particle could start at x=0, go distance L to the right, reverse direction, go a distance L to the left.

So the whole cycle covers a distance 2L

trying to draw the cycle:

each point on this circle as a corresponding value of position x (higher towards the top of the page, lower towards the bottom)

It also has a corresponding velocity v (positive on the right, negative on the left; "s" stands for "speed")

I'm thinking my life will be easier if i think of this process in terms of a coordinate on this circle, ranging from 0 to 1, like " what fraction of the way through the cycle are you"

raginrayguns

@fragariavescana said:

Shouldn't it go in a square (maybe with dotted lines at the top and bottom)?

yeah, that way position would be linear with height, whereas i was thinking of it as linear with angle

a circle is what a mass on a spring would do

a mass on a spring is a circle in phase space...

oh! with the square idea, then horizontal position could represent velocity!

which is apparently such a natural idea that @manyblinkinglights thought i already drew it that way?

@manyblinkinglights said:

Wait, what? Why would it bounce back and forth like that, in a smooth circle? Surely the shape would be different. A back and forth bounce off walls with no gravity would be almost a step change, unless you’d… get some sort of spiral… of the velocity getting less and less as the bounce got used up like isn’t the velocity constant

Yeah I tried to draw a step change, velocity is +s on the right half of the circle, -s on the left half of the circle. I was just drawing some closed loop, i didn't think it mattered what shape...

fragariavescana

To tune steam engines they used to put a stylus on the end of a pressure gauge moving in the y axis then have it draw on a piece of graph paper with the x axis attached to the piston. The amount of energy delivered per cycle would be proportional to the area of the shape traced out on the paper.

You can't physically do this with an ICE or a jet engine but you can figure out what shape it would trace (for a turbine you plot the pressure and volume of an infinitesimal packet of gas moving through the system).

#this is what much of thermo for engineers is #the same thing works if you plot temperature vs entropy #a rectangular plot being a carnot engine and all real-life heat engines being some shape inside those bounds

oh god oh fuck a giant seems to be devouring the sun

#send help

amazoogle

we've sent 2,500 senior dogs to a six week Javascript bootcamp using the funds we raised from our ransomware operation. and that's just the beginning. starting next month every fruit will be different

anphivenas

i need to get into cars

dontsaythatillcry

they have doors which help with this

relevant-wikipedia-articles

#get out of the car

yesornopolls

do you know the arabic numerals?

Do you know the Arabic numerals?

Yes

Remaining time: 1 day 22 hours

fragariavescana

Here they are btw:

0: ٠

1: ١

2: ٢

3: ٣

4: ٤

5: ٥

6: ٦

7: ٧

8: ٨

9: ٩

aorish

i wonder how long the period of early human history was where they had figured out the usefulness of fire but not specifically how to start one, other than spreading it from an existing fire.

i also wonder how long they managed to keep one going for deliberately during this time. you could imagine that they'd realize fires found outside of caves could be brought into caves, which would prevent the rain and wind from putting them out, but that they'd still need constant maintenance from new fuel, which requires cooperation and night shifts to keep the precious flame burning.

perhaps different caves shared their fires with each other, and traded it for food or clothing or other goods? and maybe they sometimes fought each other over resources and put their opponents' cave fires out once they defeated them and took the fire for themselves...

aorish

Claims for the earliest evidence of using fire by a member of Homo range from as far back as 2.0 million years ago.[2]

...

The oldest definitive evidence for fire making (i.e. igniting a new fire) dates to ~400,000 years ago at a Neanderthal site in eastern England, where burnt soil was found along with fire-cracked flint handaxes and two fragments of iron pyrite, used to strike sparks with flint.[12][1][13]

okay so "fire-gathering" has been around for roughly five times as long as "fire-making."

so then most human and early hominid social groups were probably fairly preoccupied with the preservation and maintenance of fire. if it went out people probably died

fragariavescana

There are HG groups which have fires but don't know how to start them. And I can't blame them. It's so much easier to get a campfire going from an ember that is still barely smouldering than to make fire from scratch, even if you have dry cotton wool.

Being nomadic, they have devised ways to bundle up an ember and carry it to their next site.

There's no need to feed the fire overnight. A 6" ⌀ log will still be glowing in the morning. A group of 20-50 people will want to have several hearths going so any one going out is not a disaster.

andmaybegayer

A majority (57.0%) of the standard output generated by agriculture across the EU was from the combined farms in France (17.7%), Italy (14.9%), Germany (12.8%), and Spain (11.6%) in 2023. Although Romania accounted for about one third of the EU's farms, it accounted for only 3.7% of the EU's standard output

I am reading about European agriculture. It's normal here.

#we taught this chimpanzee to understand the EU common agricultural policy and he hanged himself

tanadrin

hmm. requiring accounts to access old.reddit.com now plausibly means i just never use that site again. weird change to make.

#if only there were some kind of api which could let you avoid the need for web scrapers

trixiebunnybundle

Liberals will never ever ever ever understand this, but propaganda can be a good thing. The entire reason public health has collapsed across the world is because we have been convinced it's immoral to publish things telling people that good things are good and help them.

trixiebunnybundle

"Propaganda is unnecessary because the results speak for themselves," the results do not speak for themselves if nobody knows the results happened. If you grew up in a world that does not have polio anymore it makes no sense to begin believing polio could come back. You have to be told about it. Propaganda in favor of medical science is a form of education. This applies to political ideology too, btw

loki-zen

I think that like. "Propaganda" is like "murder".

Almost everyone believes that there are some situations in which it would be justifiable to take actions which might cause the death of another person (such as if they're running towards some children with an axe and clear intent to hurt them and you have a gun), and almost no one would consider the actions they personally would approve of to be "murder".

Telling people that good things are good and will help them is education, because definitionally the message you're trying to spread there is true. I think when people hear "propaganda", that definitely implies that your message is, if not straightforwardly false, at minimum presented in a deliberately misleading way with the intention of getting people to believe stuff that's false, or purely ideological. "Propaganda" definitely suggests that it is in someone else's interests that the message is being spread - "education" is what it's called when you tell people something true for their own benefit.

fragariavescana

Also the idea of 'indoctrinating children'.

#you can't raise a tabula rasa #and if you tried you'd be indoctrinating them with blankness

archacovercosine

[to view this post, please refer to the print version of this blog]

#incredibly crusty PDF of OP's blog

maidthings

new nilered is actually one of the best things he's put out in a while. that said i do not care for his horrible-lab spanning carbon monoxide tube. i know chemists are squeamish about open flames in the lab but surely it'd be safer to just burn off the carbon monoxide and hydrogen on the spot than carry it 20 meters over to release in the oxygen-rich fumehood

fragariavescana

steal a catalytic converter like a normal person

archacovercosine

"sane defaults" is just code for "the dev teams idiosyncratic config for programs you're never going to run".

i'll pass, on any proper install any program is at most 2 terminal commands away anyway.

fragariavescana

Forget about your silly problem, let's take a look at some of the features of the VMS operating system.

1. Options. We've got lots of them. So many in fact, that you need two strong people to carry the documentation around. So many that it will be a cold day in hell before half of them are used. So many that you are probably not going to do your work right anyway. However, the number of options isn't all that important, because we picked some interesting values for the options and called them...

2. Defaults. We put a lot of thought into our defaults. We like them. If we didn't, we would have made something else be the default. So keep your cotton-picking hands off our defaults. Don't touch. Consider them mandatory. "Mandatory defaults" has a nice ring to it. Change them and your system crashes, tough. See figure 1.