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/sci/ - Science, Technology, Engineering, and Mathematics

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Anonymous 14/12/05(Fri)02:52 No. 15993 ID: 86e709 [Reply]

File 141774435457.jpg - (78.83KB , 1000x750 , formlabs-inline.jpg )

Welp, our rapid prototyping machine ist kill.

Time to get a 3D printer to use for moldmaking plugs.

Anyone have experience they'd like to share?

Sifted 14/09/26(Fri)02:55 No. 15892 ID: 96405d [Reply]

File 141169293046.jpg - (43.01KB , 290x399 , J8seKRxKdk6RNCK6ipzejQ2.jpg )

So for everyone out there I ask you what you think the universe would be like if attraction was different. If it was likes attract and opposites repulese, so two positive charges attract same with negative and then a positive and negative repulse. What do you all think?

3 posts omitted. Click Reply to view.
Anonymous 14/11/15(Sat)12:22 No. 15970 ID: c4fc35

My guess would be not much change at all in terms of how the universe works, entropy etc.

But would we exist in it? Probably not.

Effectively you are just switching the masses of electrons and protons. The atomic structure would remain relatively similar except for heavier electrons. Would this cause them to orbit much further from the nucleus? I don't know I'm not a physicist.

But yea, if atoms functioned similarly to how they do now then organic life would be very different. Depending on the properties of the new elements it would likely not be carbon based but rather a more suitable element

Anonymous 14/11/22(Sat)08:38 No. 15977 ID: abc87c

I think this was explored as a mathematical possibility in the early universe when antimatter still outnumbered matter a buttfucktruckload to one, and much weirdness abounded.

I forget what all went down but in short, that shit worked briefly, and then worked itself out. It... went away, OP.

Anonymous 14/12/01(Mon)17:08 No. 15992 ID: 972965

ITT: People not realising OP just asked "What happens if you reverse time"
>Reverse the big bang

Anonymous 14/07/25(Fri)22:51 No. 15766 ID: 86e709 [Reply]

Youtube  Everything I've read about Eugenics has been about how it's pseudoscience. Ok. but, by the sound of it, it was just a selective breeding program. If artificial selection works in every other species, and natural/artificial selection has produced us, ...where's the problem exactly? I have yet to see how a sophisticated selective breeding program couldn't produce a better human body or brain or both. It's what we do every time we pick a mate who we think will make us some primo offspring.

pic semi-related: Just try listening to this without clawing your eyeballs out (why are so many people so fucking retarded and how can we replace them with upgraded models?)

8 posts and 1 image omitted. Click Reply to view.
Anonymous 14/11/25(Tue)16:24 No. 15987 ID: e3615c

I think a better alternative would be like what appears in the movie Gattaca. You take many gamete samples from the future parents and fertilize them in vitro. You keep only the zygotes that meet certain criteria for health (optionally freezing a few in case of miscarriage or some other problem) and you implant one in the mother.

Anonymous 14/11/30(Sun)21:20 No. 15990 ID: 96b946

What about unintended consequences?

Like, for example," Oh hurray! We have bred sickle cell out of existence! But wait oh fuck now everyone is dying of malaria"

Or like how rainman idiot savants are a cunt hair away from being the next Issac Newtons.
Get rid of the retards, get rid of the possibility of greatness.

Anonymous 14/12/01(Mon)04:19 No. 15991 ID: 86e709

The downs side of that would be no greatness, unless, oh shit, a whole generation of autistic savants... because who cares, it eliminates war, and robots and androids unburden us from the shackles of menial tasks and physical labor, agriculture, maintenance, freeing us up to contemplate mathelamatiques and phirosophry and awwt aww day. They can all be sterile, finally uncoupling sex from our reckless primitive approach to reproduction, so people can mate purely for social purposes. Reproduction only happens when intended and it the parents are committed, stable, and financially sound to care for the young, in addition to engineered fetuses cleaner, healthier genomes.

Plus, bonus upside, all cunts can easily be hairless cunts.

Incredible sounds from the Universe collected by the NASA spacecrafts! MagikBit 14/11/27(Thu)22:44 No. 15989 ID: 318e23 [Reply]

File 141712468555.jpg - (5.55KB , 100x100 , bigbang.jpg )

Incredible sounds from the Universe collected by the NASA spacecrafts! They can be listen on:

Anonymous 14/11/22(Sat)00:15 No. 15973 ID: 7fa0bd [Reply]

File 141661174892.jpg - (104.70KB , 640x360 , portal dalek.jpg )


2 posts omitted. Click Reply to view.
Anonymous 14/11/22(Sat)23:44 No. 15980 ID: 5d199c

To me they look like portable life-support/coffins. Picture some 112 year old codger wrinkled up inside one guiding it round akin to a spaz marin dreadnought. That way the expired can enjoy 'normal' life well past their expectancy.

Anonymous 14/11/24(Mon)05:42 No. 15983 ID: c4e26c

So like, a Dalek then.

Anonymous 14/11/26(Wed)20:43 No. 15988 ID: ab4c09


lol ftw.

America VS the metric system Anonymous 11/11/28(Mon)22:57 No. 12847 ID: 2dcfee [Reply] [First 100 posts] [Last 50 posts]

File 132251746298.jpg - (33.63KB , 400x308 , FAT AMERICAN.jpg )

It’s hard to find comedy gold like this, however this is priceless


Apparently a true American tries to show the failures of this evil satanic scientific metric system and fails horribly.

Best parts:

1) Arguing that centimeters are not part of the metric system!
>"Centimeters, while in common usage, are NOT officially recognized metric units"

2) Actually trying to measure something using 0.1 mm obviously not understanding that this precision is not actually possible with human hands.
>"In metric notation this would be 1219.2mm by 2438.4mm."

126 posts and 10 images omitted. Click Reply to view.
Anonymous 14/11/22(Sat)16:27 No. 15979 ID: 287212


Are you saying that 3 meters = 9 feet?

Anonymous 14/11/23(Sun)09:48 No. 15981 ID: d2ef46

Why does this thread still exist. Every time I visit this board, it's on the front page, hosting a series of one retarded comment after another.

Just learn both. You assholes sound like those people who think everyone in the world should only speak one language. It's fucking stupid. Could a mod please lock this thread?

Anonymous 14/11/24(Mon)06:20 No. 15985 ID: c4e26c

The construction industry was the source of the backlash when the U.S. tried converting to metric in the 60s. Muh Two Bah Fer!!!

Well, a 2x4 was a convenient size, a 2x6 or 10 was as well. No one wanted to complicate matters. Forward to today, and lumber mfg's have repeatedly shaved so much material off their finished products, those numbers are nominal only. A 2x4 is actually roughly a 1.5x3.5, precision & tolerances depending on mfg's QC.

So these toothless bearded fags are already using screwey numbers... Running an entire project with tens of thousands of calculations made based on this idiocy, and all the fucking trouble it causes when the new guy builds shit based on the wrong sizes, they can live with, but calling a 2x4 what it actually is, a 4x9, 4cmx9cm, BLOWS THEIR FUCKING MINDS.

Further proof Europe sent its most retarded and stubborn inbred hicks to populate this country.

Anonymous 14/10/19(Sun)11:15 No. 15940 ID: e9758b [Reply]

File 141371012595.jpg - (61.35KB , 700x479 , 17775_lores.jpg )

How much money you reckon ebola raised for in the name of science? thanks little fella!

3 posts and 1 image omitted. Click Reply to view.
Woo. 14/11/01(Sat)16:07 No. 15959 ID: 2429da

File 141485445093.jpg - (95.39KB , 945x552 , ebola-body-bag.jpg )

Thank you, little buddies! :D

Anonymous 14/11/18(Tue)05:41 No. 15971 ID: a4fae5

>that one laughing nigger in the middle

Anonymous 14/12/26(Fri)12:41 No. 16011 ID: 243dac

I don't see anyone laughing because none of them are.

Parabolas in autodesk inventor Anonymous 14/11/04(Tue)17:45 No. 15963 ID: b2989d [Reply]

File 141511955922.png - (2.77KB , 197x256 , parabola.png )

I need to create a parabola in autodesk inventor for a school assignment, and the parabola needs to be shaped like the bottom of a circle (kind of like a lid) what do?

Anonymous 14/11/08(Sat)09:40 No. 15965 ID: 789203

>the parabola needs to be shaped like the bottom of a circle
Well, that's not a parabola then, is it? It's an arc.
arc(x, h, v) = (v / h) * sqrt(h^2 - x^2)
h being the radius of the horizontal elliptical axis, and v the same of the vertical one.

Anonymous 14/10/12(Sun)19:00 No. 15929 ID: b20a90 [Reply]

File 141313325435.png - (193.71KB , 450x450 , BT clients.png )

Hello /sci/!

Does anyone please know of a program that can analyze torrents? What I want it to do is to create a printout of all the files in the torrent. I also want to make comparisions of torrents; to see if two torrents have files with the same name and/or the same hash value.

Anonymous 14/10/16(Thu)11:00 No. 15936 ID: 789203

Yes, dumptorrent.

Hashes are computed per-block, not per-file. Meaning, the hashes a torrent contains will depend not just on its particular contents, but also the particular order in which they appear, and the block size that was used. It's very unlikely that two distinct torrents containing the same file will also share any hashes, even if the block sizes are the same. It's even less likely if the file in question is smaller than twice the block size.

Let n be the absolute offset of the file on the torrent A (given by the sum of all the file sizes that came before), and let m be the same on B, if file_size >= block_size * 2 and n is congruent to m modulo block_size, then there will be at least one duplicate hash between the two torrents. For randomly constructed torrents (a reasonable situation) with a random file_size the probability of the congruency condition being met is of 1/block_size. So for block_size = 4 MiB (a common block size), the probability is lower than four million to 1.

Anonymous 14/10/07(Tue)08:26 No. 15918 ID: 1b02b6 [Reply]

File 141266316925.png - (44.05KB , 993x834 , dfgdfgdfg.png )

2 questions. In photo,

Exhibit 1: A point charge q exerts its electric field over a spherical body. Along the flux lines diverging "radially" away from point charge, there exists 2 points at opposite ends of sphere's surface area (along diameter). The electric field, E, in accordance with Coulomb's law, is stronger towards the charge than away from it, the vector lengths of E indicating this ever dying weakness, and vectors, dA, normal to the area.

Told: That the total electric field on the body is zero, because the cross product of the electric field on both points are "equal" but opposite, cancelling each other out. This applies to all points along surface area of the sphere.

Question: What is wrong in my photo? It seems that they have completely forgotten about Coulomb's law, in that the closer you are to a body, the stronger the electric field. If the point charge was negative, I imagine the electric field vectors to be a lot larger along the sphere's hemisphere closest to the point charge, and smaller on the other hemisphere. Wouldn't all but the tiny difference between the electric field strengths remain after cancellation? Shouldn't the total electric field be in slight favour of the negative charge's force?


Exhibit 2: a. A point, p, inside charged sphere has an electric field, E, of zero.
b. A point, p, exists in the sphere of a charged similar body comprising a sphere with an attached appendage that loops around half the sphere, with same electric field as E in exhibit 2a.

Told: That in all closed surfaces, the net electric field, E, at any point in the closed system is zero.

Message too long. Click here to view the full text.

Anonymous 14/10/07(Tue)09:10 No. 15921 ID: 1b02b6

Also, why are the charges along the surface? Is it just easier to think that way after summing all the negligible point charges together?

Anonymous 14/10/10(Fri)03:15 No. 15926 ID: 789203

1. I don't see how the field strengths on the surface could possibly have opposite directions unless the point charge is inside the sphere.

2. I agree with you, it seems counter-intuitive. I could easily construct a closed fractal shape that has infinite surface area on one side of the charge and is nearly spherical on the other. I'm not in physics, so I don't know what to tell you. See if this link helps:

Anonymous 14/10/10(Fri)19:00 No. 15928 ID: 1b02b6

I worded it poorly. E isn't opposite on both ends, dA is (normal to the surface on opposite ends). I was just trying to say that the field dies off the farther you are away from charge.

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