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/sci/ - Science & Technology

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Anonymous 09/11/24(Tue)15:11 No. 6203 ID: 15987b [Reply] [First 100 posts] [Last 50 posts] Stickied
6203

File 125907191192.jpg - (15.84KB , 240x240 , resnickhalliday.jpg )

Up until a couple months ago, I had always thought that I sucked at physics, and had grades to corroborate. Then I found this book to the left: the Resnick/Halliday/Walker. All of a sudden things made sense in class and my grades shot up. Right now I'm lightyears of ahead of my class in physics. So my question textbooks does /sci/ reccomend for physics, chemistry and math?

This is now the textbook and and book request thread


124 posts and 17 images omitted. Click Reply to view.
>>
Anonymous 13/05/13(Mon)21:25 No. 15060 ID: fc1034

Could anyone recommend me a detailed book on quantum theories in physics?

Things like Spectral emissions and absorptions, wave-particle duality etc.

I'd appreciate it very much.




Anonymous 13/05/23(Thu)03:57 No. 15084 ID: c433fd [Reply]
15084

File 136927427192.jpg - (38.92KB , 500x355 , toblerone.jpg )

http://www.cclonline.com/product/74376/22919700/Blank-Backup-Tape/Maxell-LTO-Ultrium-4-800/1600GB-Data-Cartridge-Single-/MED0123/

>1.6TB storage capacity, 240MB/s write speed, not even £20
jesus fuck, could somebody please explain to me why magnetic tape storage is considered obsolete again, and why its not in greater use?


2 posts omitted. Click Reply to view.
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Anonymous 13/05/23(Thu)14:32 No. 15087 ID: 4fef91

It's not because they're fragile. It's because they are linear devices. They're amazing for achiving if you keep them in the right conditions but quite a few people who use them 'casually' don't know that.

Their biggest problem is, as mentioned, them being linear devices. This is great if you want to store rarely accessed information but if you want to access multiple files on it you have to wait ages for it to wind back and forth finding them.


>>
Anonymous 13/05/23(Thu)16:00 No. 15088 ID: 85dfcd

>>15087
Oh yea, it's been so long since we used em, I forgot about the waiting...

But we just threw out a pile of tapes that were unrecoverable because sometime between 1994 and now, the hvac went out. Optical media wasn't a whole lot better. At some point someone started buying cheap discs, and the 60-70 year lifespan of cdrs turned out to be more like 7-10 years. :/

We're a mid-size architecture firm, so what works for us might not work for you. We now utilize a selection of online services for collaboration & backup, depending on the type of the data, though each computer also saves delta backups locally to ext HD's (themselves backed up across the network at night) for general data and our windows VMs, simply via the built-in Time Machine software for quick recovery & version tracking.

If you're an individual, using Dropbox is probably the most bang for your buck. Try that & see.


>>
Anonymous 13/05/24(Fri)04:48 No. 15091 ID: ce40f2

>>15088
>At some point someone started buying cheap discs, and the 60-70 year lifespan of cdrs turned out to be more like 7-10 years.
Seriously. Optical discs can go suck a dick.

Myself, I've found that internal HDDs connected to a dock via eSATA have the best reliability/speed/price-per-GiB relation, as long as you only turn them on once in a while.




Anonymous 13/03/10(Sun)14:56 No. 14792 ID: 6d0b17 [Reply]
14792

File 136292376118.png - (35.87KB , 946x522 , repro life.png )

/sci/ WTF is this?

Genius or pedo-pseudoscience?


25 posts and 1 image omitted. Click Reply to view.
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Anonymous 13/05/17(Fri)06:51 No. 15071 ID: 54cc34

Up until the early 1900s it was the norm for girls to marry and start reproducing at about 15. Any woman older than 23 who hadn't found a husband was an 'old maid'. So yes, it's completely valid.


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CandleJack 13/05/18(Sat)02:21 No. 15074 ID: 2f260d

>>15068

Did you... did you seriously use a joke version of a tabletop RPG trait chart as a determiner for anal capacity in real humans?


>>
Anonymous 13/05/23(Thu)21:27 No. 15090 ID: c1bebf

>>15074

>joke version

I regret to be the one to have to inform you, but that's no joke. That table is part of a real roleplaying system, and is quite likely to actually be referred to in a game of FATAL.




Anonymous 13/03/18(Mon)09:16 No. 14823 ID: bff592 [Reply]
14823

File 136359456294.jpg - (135.01KB , 750x800 , image.jpg )

How does this board feel about the "singularity theory"?

Is it safe to assume some of the predictions about the time it will occur are true?
What repurcussions on society, culture, etc will this have if it happens?
Thoughts?


19 posts omitted. Click Reply to view.
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Anonymous 13/05/20(Mon)01:52 No. 15081 ID: ce40f2

>>15078
I made a couple mistakes:
1. The first output of answer() should be 2^32-2^8.
2.
>will likely output lists in different order each time it is run, even for the same output
Last word should be "input".

>>15079
>I understnad the theory, I just don't think it's going to work.
I can't say such inflexibility surprises me.

>No matter how complex the device, and how encompassing the program, there will always be limitations.
Humans have limitations, too. What does that imply?

>We will eventually make one capable of killing us
Message too long. Click here to view the full text.


>>
Anonymous 13/05/20(Mon)08:28 No. 15082 ID: ca12bb

there's 3 states of a binary function

0/1/-

power off, power on, the computer is made of bamboo and there's an electrical fire

the coin analogy is correct therefore

you wanted abstract, you can have abstract


>>
Anonymous 13/05/23(Thu)19:29 No. 15089 ID: c1bebf

>>15077

>the programs are still stuck on traditional mechanics.

Because programmers are still figuring out the possibilities and requirements of the new architecture.




Anonymous 12/11/06(Tue)15:04 No. 14344 ID: f98e47 [Reply]
14344

File 135221065037.jpg - (103.94KB , 500x359 , era1-nowmap.jpg )

Hi /sci/, I have a question,

I've been thinking about certain things a lot lately, and something that's been bothering me immensely is that the Big Bang Theory (the theory, not the fucking show) is so widely accepted and taken for granted, without there being any actual proof except for blue-redshift values.

What I'm trying to say here is, well, the Big Bang is an event, right? And any event is defined by a time, and location (4 dimensions, if you want me to be exact). Since it is so widely believed that the Big Bang also was the beginning of those 4 dimensions, how can you hope to define it as an event? And if it isn't an event, did it even happen?
Just to elaborate a bit; let us say that there were coordinates of the big bang. These would surely be time = 0 and the spatial xyz's also = 0.
Now, here's the problem. This indicates that these coordinates already existed before the Big Bang (thus nullifying the theory) or, more plausible, being created at the exact same moment as the BB. This would indicate that they were not created BY the BB, but rather simultaneously. Which would then render the BB redundant in any other aspect that origin of mass.

I've done my fair share of reading on multiple aspects of it (planck epoch etc), and can't seem to come to a conclusion. So what does /sci/ think?


39 posts omitted. Click Reply to view.
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sombr3toile 13/05/16(Thu)22:45 No. 15070 ID: f64411

I just read all the thread and I'm surprised : Inside the question, there are a lot of "parti-pris" (sorry, I'm french...)[position already decided will be a good approximation.]
"the Big Bang is an event. And any event is defined by a time, and location (4 dimensions, if you want me to be exact)"
What do you think about mass (and then gravitation...) ? about energy (this field is even more open...) ? about probability (does this event even existed...?) ?

for my eyes, trying to approaching the big band only with the ideas of location and time seems like trying to fly with a bicycle (you can jump but not fly !!!). It will be not really possible. You will approximate the idea but not be able to make the leap...
The thing is : there are ideas, constructs, abstractions created by the limited human who have naturally conscience only of space and time. Maybe this will be the enigma who will stay unsolved, the human brain doesn't have the capacity to understand this "abstraction/construction/event". This is a "godlike" thing for me ... poor human mind with human abstractions (wich be totally false, by the way !)


>>
Anonymous 13/05/18(Sat)08:01 No. 15076 ID: ce40f2

>>15070
>"the Big Bang is an event. And any event is defined by a time, and location (4 dimensions, if you want me to be exact)"
>What do you think about mass (and then gravitation...) ? about energy (this field is even more open...) ? about probability (does this event even existed...?) ?
What do I think about them? Well, first of all, they're not events. The mass of the sun doesn't occur at any point in time, nor does its output energy.

>or my eyes, trying to approaching the big band only with the ideas of location and time seems like trying to fly with a bicycle (you can jump but not fly !!!). It will be not really possible. You will approximate the idea but not be able to make the leap...
>The thing is : there are ideas, constructs, abstractions created by the limited human who have naturally conscience only of space and time. Maybe this will be the enigma who will stay unsolved, the human brain doesn't have the capacity to understand this "abstraction/construction/event". This is a "godlike" thing for me ... poor human mind with human abstractions (wich be totally false, by the way !)
This is just an excuse not to think.

If you'll excuse my use of (a modified) Pascal's Wager: We can either assume that a given cosmological object has fathomable or unfathomable properties. If we go with the latter option, we can't reason about the object, and whether right or wrong we're no closer to any truth; if we go with the former option and we're wrong, we're not worse off. If we're right, uncovering the mysteries of the universe is within our reach.


>>
Anonymous 13/05/21(Tue)22:35 No. 15083 ID: af5591

It is called bang because the universe came from an expanding high-energetic concentration of mass and energy. (By mass; I mean baryons. I dont know if they have any promising theories to explain if the extra baryons in the beginning was there in the first place or something breaks the baryon conservation in the early universe.) Explosion, is by definition, that. There was no conventional "explosion" as if something lit a fuse and it happened. Also; linearity of time is an illusion (you can also think the horizon problem); you need only consider the metric in appropriate ones, the t=0 disappears.

Without proof, though, its all conjecture. The only way to be sure is build a very good neutrino detector to gain more knowledge (neutrino decoupling was around t=10 sec i believe) of the early universe and try to do something with that.

Also; "creation" of coordinates at t=0 would imply the creation of information; which violates 2nd law of thermodynamics and since it is entropy that determines the direction of time flow, usual time progression ideas would not be valid anyway.




plane Anonymous 12/11/18(Sun)21:09 No. 14427 ID: fb908a [Reply]
14427

File 135326934614.jpg - (54.35KB , 384x288 , Futuristic_Plane[1].jpg )

Hi /sci/, I'm making a concept of a electric jet. What would you use as a energy storage. It should contain 3 MW/h and weight less then 400 kg.


3 posts omitted. Click Reply to view.
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Anonymous 12/11/19(Mon)06:26 No. 14435 ID: a15490

Is the 400kg including the passenger?


>>
Anonymous 12/11/19(Mon)09:21 No. 14436 ID: fb908a

>>14435
The whole plane including the passenger and extra equipment should weight ~1000 kg


>>
Anonymous 13/05/17(Fri)06:59 No. 15073 ID: 54cc34

Forget storing the electrical energy, what you need is to generate thrust spontaneously and consistently. Magnets.
http://theorydesignsjonl.blogspot.com/




SD or SATA 4 ATA? Anonymous 13/05/15(Wed)09:59 No. 15062 ID: 146fb8 [Reply]
15062

File 136860475822.jpg - (77.17KB , 800x600 , 800px-Pointing_stick.jpg )

Hello /sci/!

I'm considering buying an old ThinkPad and run Linux on it. It will only be used for coding and basic surfing. (Not even one single MP3 will touch the computer.) However, the weak link is probably the old HDD.

Is it possible to run a 2.5" SATA SSD on the ATA?

I've read about adapters that makes it possible to use a SD as HDD. Are And are SDs reliable enough to use for at least 40 hrs a week for 9 months without lagging or crashing?


>>
Anonymous 13/05/16(Thu)00:39 No. 15064 ID: 02c598

If you really wanted to use it for nothing but surfing you could get a budget microUSBdrive plug it into an avalible port and run linux off that. Set the HD for the temp files.

I've been doing this for over a year now with an old 1Gb stick I found in the bottom of my draw and yet to encounter problems.


>>
Anonymous 13/05/16(Thu)11:41 No. 15067 ID: 146fb8

>>15064
I have considered that. But I prefer to have as little stuff as possible. I stick to the rule one item-one use. (Ok, a coumputer can be pretty much exactly what you want it to be, but you get the idea.)

So has anyone managed to let a laptop use an internally mounted memorycard as a HDD?




how can i make a usb spike drive as 13/05/13(Mon)05:45 No. 15058 ID: 575447 [Reply]
15058

File 136841673860.jpg - (25.09KB , 400x400 , dinosaur-drive.jpg )

how can i make a usb spike drive i want to make 1 to understand it beater


>>
as 13/05/13(Mon)05:48 No. 15059 ID: 575447

getting in to computer security fild

also is there any laws ageist them




Anonymous 13/05/08(Wed)16:04 No. 15039 ID: cb9fa8 [Reply]
15039

File 136802186982.jpg - (71.87KB , 473x542 , 248196_10151877897823626_1791319101_n.jpg )

Physics state that time is not linear, how can we state initial conditions as a paramater for the non-biological dimensions?


>>
Anonymous 13/05/09(Thu)14:45 No. 15047 ID: 9d00be

Oh look! It's cb9fa8 again!


>>
Anonymous 13/05/12(Sun)20:01 No. 15056 ID: ad681f

Two things come to my mind. cb9fa8 either doesn't know that his questions are awkward and too numerous for 7chan's easy going culture, or cb9fa8 is some kind of student doing a social experiment where he asks these questions on purpose. Either way, I'm going to take a stab at this:

You claim that physics state that time is dynamic (despite there being theories which state otherwise, but let's ignore those for now), which means traveling back into the past and performing an action will have effects on all events afterward, like in Back to the Future or Terminator.

Next, you say "initial conditions as a parameter". This, to the lay man, means "the variables at the beginning as a determining effect". This makes little sense logically, so let's change it to "the way in which the variables at the beginning had a determining effect".

After that, you state "non-biological dimensions". This, as far as I know, refers to anything inorganic in general. They are the dimensions- the aspects- which are not biological. And since you don't specify a certain set of non-biological dimensions, you are actually referring to every single non-biological aspect in the universe.

So, what you're asking in lay man's terms, is:
"Since events in time can be changed by time travel, in what way can we say how the events at the beginning had some shaping effect in everything which isn't alive?" Another way to phrase it is "Since time travel changes things, how can we say that the big bang created everything?"

Kind of a non sequitur, but the answer to your question ought to be: Science.




REC Solar Rickrolled Taco 13/05/10(Fri)02:25 No. 15050 ID: b2c65e [Reply]
15050

File 136814552770.png - (16.63KB , 220x84 , 220px-Rec_solar_logo.png )

sup /sci/lons

instead of some of the shitposts that are frequent here due to all the summerfags, lets change it up a bit. I have a offer for you all to make some money.

I work for a solar home electric company by the name of REC Solar. We have a referral program were if you refer someone to us and they buy a system, I can get you $500. Obviously i'm not asking you to post names and personal information here for everyone to see.

Quick info on what we offer:
>> We try to offset your electricity by 100%. Obviously the way your roof is built and it's alignment to the sun will affect everything.
>> Return on investment is 7-8 years typically
>> 15 year warranty
>> Options to buy or lease.

My email is: rwtv1989@cox.net <-- send me your information and the person you're referring.


>>
Rickrolled+Taco 13/05/10(Fri)02:26 No. 15051 ID: b2c65e
15051

File 136814557479.gif - (67.47KB , 664x376 , contact-map_1_0.gif )

We're not located everywhere, so here is a map.
If you know someone in these areas though we can still give you the referral money.


>>
Anonymous 13/05/10(Fri)02:50 No. 15052 ID: 39770f

That's nice, OP. But how do I know I can trust you? Please post your full Name and Social Security Number so I can run a background check on you before I start giving you other peoples personal information.

Thank you.


>>
Rickrolled+Taco 13/05/10(Fri)09:06 No. 15053 ID: b2c65e

>>15052
lol, good point.

All I need is your name (nickname is fine), phone, and address.
No social security or any of that.




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