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

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Magnetic Particle Inspection Anonymous 18/03/17(Sat)16:37 No. 16634 ID: bf1cc6 [Reply]

File 152130103222.jpg - (117.55KB , 563x422 , Magnetic Testing.jpg )

Anybody on this board done any MPI and has experience with different methods. Im newish and want to learn some new ways that are better suited to my work

Is cold air denser than hot air? Anonymous 18/02/27(Tue)19:46 No. 16630 ID: dfa669 [Reply]

File 151975716827.jpg - (92.68KB , 1024x768 , IMG_0592.jpg )

Plz help

Anonymous 18/02/28(Wed)01:07 No. 16631 ID: a5c275

Yes. You would have known that by now: hot air balloons rise due to the warm air being less dense. The molecules in warm air spread out, becoming less dense, conversely, cold air molecules remain close, making it dense.


Anonymous 18/03/02(Fri)04:56 No. 16632 ID: 6914e6

volume = mass / pressure * temperature * constant

If you hold all the variables on the right side but increase the temperature, the volume also increases, and since density = mass / volume, when the volume increases, the density decreases. So an ideal gas under constant pressure becomes less dense as the temperature increases.

Anonymous 17/08/28(Mon)20:04 No. 16539 ID: 269c1e [Reply]

File 150394348278.jpg - (28.69KB , 400x300 , bad-math-fotolia-29084487.jpg )

I'm hoping to return to college and do a second degree in math/a math related subject (ideally Computer Science). Unfortunately, I haven't done math in well over a decade, and when I did math previously it wasn't exactly the highest level math.

Can anyone recommend how I can best learn/re-learn/catch up to college level math and be ready and prepared?

11 posts and 3 images omitted. Click Reply to view.
Anonymous 18/01/22(Mon)00:19 No. 16617 ID: 7332e9

If he’s catching up to college level stuff he has to do highschool math first, best starting with analytic geometry ending somewhere in calculus I or II.
Arithmatic mastery will make the difference between doing well on a timed test, and the discipline from mastering arithmatic when used to master secondary school math concepts will make the difference between getting 80s n 90s vs getting 100s.

Anonymous 18/01/22(Mon)10:08 No. 16618 ID: 2a858b

>the discipline from mastering arithmatic when used to master secondary school math concepts
So please explain how arithmetic helps you solve quadratic equations, or systems of linear equations.
Like, if I need to find the exact roots of f(x) = -sqrt(pi) * x^2 + e*x + 10, how does it help me to know how run a multiplication algorithm by hand?

Anonymous 18/02/09(Fri)23:58 No. 16622 ID: bee93c

which one

start learning about computers Bigattao 16/03/10(Thu)06:19 No. 16297 ID: 00af9a [Reply]

File 14575871945.jpg - (186.25KB , 860x450 , Engenharia_de_Computacao-BLOG-860x450_c.jpg )

Hi sci,
I'm a noob about computers and going to do college of Computer Engineering. I don't know even how to start learning. Can somebody give a tip?

10 posts and 2 images omitted. Click Reply to view.
Arduino is a great place to start! Anonymous 16/12/30(Fri)09:26 No. 16404 ID: 01d2f8

Code academy and cybrary are pretty helpful sites but I really learned a lot building and programming little projects with the arduino mega2560. Jeremy Blum has some great tutorials on you tube to get you started. Also building raspberry pi projects is a great way to get your feet wet. Best of luck to you.

Nooby Anon 17/01/07(Sat)07:51 No. 16408 ID: 122f98

Also use Udemy if you have a little bit of money their courses are very informative and useful. Also very good for Python beginner courses.

Good luck bro

Anonymous 18/02/01(Thu)04:53 No. 16621 ID: fcbe0a

how good is cybrary? been told it's a meme and not too good

Overrated robot threat Anonymous 17/12/01(Fri)00:40 No. 16587 ID: e4210a [Reply]

File 151208524377.jpg - (54.24KB , 823x540 , 08902844.jpg )

So I've read the n:th alarmist article about how robots will replace some 800 M people before 2030 and so fucking on. It will be an endless summer citizen's wage afternoon until the AI exterminates us and so fucking on.

Tell you why this is not going to happen?

3 posts and 1 image omitted. Click Reply to view.
Anonymous 17/12/01(Fri)13:49 No. 16594 ID: e4210a

Easier, maybe. The wage is a strict union question. Maybe we have to re-assume a lot of things. The post-WW2 economy was founded on the assumption that there would be an constant growth. Then the financial markets got de-regulated and the financial sector grew too large. That was some 40 years ago and the unions haven't still caught up.

And another thing the unions have to catch up is the introduction of computers. I don't recall the name, but there was a french sociologist who in the 70-s warned that computerization would change the work. Back then computers was magic boxes that no one cared about.

Anonymous 18/01/20(Sat)22:51 No. 16614 ID: 7332e9

that would be relevant if he was doing college level math
but hes not
hes catching up to college level math
hes doing highschool analytic geometry and precalculus and basic calculus.

Anonymous 18/01/30(Tue)01:35 No. 16620 ID: a2a9aa

The idea of people losing jobs to machines is nothing new, it's when the machines appreciate the concept of currency that you will have a problem.

Earth Hole Anonymous 17/01/05(Thu)16:26 No. 16406 ID: 4318e8 [Reply]

File 148362999864.jpg - (6.12KB , 300x174 , hjjfokjfklerajogfiaejrgfaer.jpg )

Hello /sci/. If there was a giant hole in the earth leading from one end to the other and- if you jumped in- would you just be pulled to the other side, or just be trapped in the middle by gravity?
>Pic unrelated

4 posts omitted. Click Reply to view.
Anonymous 17/07/18(Tue)15:21 No. 16528 ID: 9eed6d

File 150038406684.jpg - (583.52KB , 8525x4795 , renakinblue - Copy.jpg )

You would bounce a view times around the center just like in that star wars spoof scene- like a jojo or what that crap is called...

Anonymous 17/11/10(Fri)21:43 No. 16576 ID: ea535a

you would be trapped like a spring

Anonymous 18/01/12(Fri)09:30 No. 16612 ID: 42dc73

>people still doesn't know how gravity doesn't work

If there was a hole like that then the planet would just merge back into a ball because o gravity. Let's say it doesn't then it means the whole planet somehow lost a lot of mass which means that the planet is going to fall to you because your gravity pulls it to you.

Difference between instruments playing the same note Anonymous 17/11/30(Thu)16:21 No. 16585 ID: 864454 [Reply]

File 15120552626.jpg - (85.73KB , 1180x613 , rd-2000_hero.jpg )

At the same pitch? I'm trying to create a piece of music from an advert since I cannot seem to pay anyone enough to recreate it as they fear copyright backlash as a piece of production music.

The original track uses several synthetic guitars



This is my reasonable attempt :

I'm an expert at the piano but unfortunately don't really know much about guitars and that's why despite me playing the same notes at the same pitch, it sounds almost entirely different.

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

Anonymous 17/11/30(Thu)17:03 No. 16586 ID: f9cb15

It's not possible to explain it in analogy to sine waves, because instruments are not sine wave generators. If instruments were capable of producing perfect sine waves at consistent phases, frequencies, and amplitudes then yes, they would all sound the same.

Comparing an electric guitar to a piano:
1. Plucking a string causes it to vibrate differently vs. striking it. For a given pitch, this generates differently shaped "main waves", which itself gives the sound different harmonics. Compare the sound of a piano to that of a harpsichord. The harpsichord has more harmonics.
2. The guitar doesn't have a resonance chamber, nor do its strings vibrate the air directly. Instead it uses electromagnets to measure the distance of a piece of metal several thousand times per second. Because the strings vibrate perpendicularly to the pickups, this adds a non-linear distortion to the wave, which adds harmonics.
3. Certain maneuvers are possible in a guitar but impossible in a piano. For example, a piano is not capable of doing a proper glissando, because it can only produce notes at discrete ranges. A guitar is also able to do tremolo, which I think it's impossible with a piano.
4. Finally, different mechanisms of producing sound cause the attack, decay, sustain, and release phases to have different lengths, which also affects the "feel" of the sound.

Anonymous 17/12/01(Fri)09:22 No. 16593 ID: 0c2267

i think some of your later notes are off
also it will sound slightly different if it's in the context of a chord or if there are other parts playing
i think i phrased that wrong
a phrase will sound different in terms of "mood" or "tone" (not tone as in timbre, etc) if it has accompanying notes
i think i phrased that wrong again
Also yes the timbre of an instrument and the harmonics/partials will effect how it is perceived
it probably shouldn't be so different that it sounds so wrong
try a different register, play higher
check your notes again

Request: Post HD images of technology Anonymous 17/10/08(Sun)00:10 No. 16561 ID: 864454 [Reply]

File 150741422126.jpg - (105.64KB , 640x966 , OracleExadataExalogic.jpg )

Hey guys, I recently started a computer science class in college and my networking teacher who is the head of the IT department wants us to impress him with the best personalization of our desktops.

> inb4 impress him with your computer programming skills as opposed to flashy images

No anons, No. The motto that he always repeats is that it's important to be "all rounded". He's seen lots of autist computer geeks who are geniuses at what they do but are pretty much mediocre/shit at nearly everything else in their life (social skills, organisation of themselves, writing CV's).

I would like to show off images that highlight an interest in tech along with high quality photography; so if I may ask you kindly to post your favorite images

> I would to the other chan but those fags banned me since June of this year and my shitty ISP hasn't renewed my "dynamic" I.P. address for 4 months.

4 posts and 2 images omitted. Click Reply to view.
Anonymous 17/10/27(Fri)02:12 No. 16569 ID: 43ed39

A modern computer is an adult's toy. It is a gateway to entertainment. If the computer is not pleasing to the eye of the user, then its entertaining value will be diminished. Smear a computer with feces, and most people won't even want to use it because it stinks so badly; in this case, the computer's usefulness has dropped to zero.

Anonymous 17/10/27(Fri)16:15 No. 16570 ID: 012486

Your entire argument hinges on the premise that a computer must be within eyesight of the user in order for them to use it, which is an undemonstrated assertion. You can always hide an unpleasant computer under a table, inside a cupboard, or even in a different room.

Additionally, this is a non sequitur:
>If the computer is not pleasing to the eye of the user, then its entertaining value will be diminished.
This is like saying that the quality of a movie is affected by the appearance of the theater's entrance.

Anonymous 17/12/01(Fri)08:53 No. 16591 ID: 86f262

personalization of the desktop doesn't sound like a assignment....

if you want to make it personal, you need to take the picture yourself. There is nothing special about a good quality pic from the web.

For offtopic, i second this guy -> >>16570
Offcourse i would choose the ugly powermachine instead of nice looking computer that barely even computes.

Anonymous 15/07/26(Sun)20:15 No. 16178 ID: c84a9c [Reply]

File 143793450731.jpg - (80.44KB , 8000x500 , solarsystem.jpg )

i just need to upload this somewhere
that fucking bitch tinypic breaks 8000 wide pics

3 posts omitted. Click Reply to view.
Anonymous 17/10/06(Fri)21:13 No. 16560 ID: 33427e

Do you mean the Latin alphabet?

Anonymous 17/11/23(Thu)02:48 No. 16582 ID: ca57ba

It's actually Polish, which uses the Latin alphabet. It's missing a lot of the marks over the letters though, like in księżyc for moon.

Anonymous 18/04/02(Mon)23:33 No. 16637 ID: 5d0ff5

i think you mean imgoat

Top 11 Worst Location Data Privacy Breaches aladin 17/10/04(Wed)10:58 No. 16559 ID: 4a193f [Reply]

File 150710751028.jpg - (46.50KB , 960x560 , Overview-of-Location-Data-Breach.jpg )

Although we think our data is safe, we often give chunks of it away to third parties without the proper knowledge of how that information is stored and used. And we also don’t have a clue about the most important thing of all, how do companies keep our data safe. In most cases, it was discovered that our data isn’t as safe as we thought. Just look at Yahoo, and the company’s two massive data leaks; back in 2013 and, 2014 more than 1.5 billion user accounts were affected by all kinds of personal data being compromised. Users’ real names, passwords, email addresses, dates of birth, and telephone numbers were stolen, making the breach the biggest one in history.

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