/sci/ - Science & Math

>>7584504
maybe. There is spirulina, but you can't eat it all the time or you get gout:
http://www.projectrho.com/public_html/rocket/lifesupport.php#id--Closed_Ecological_Systems--Growing_Plants--Algaculture


Algaeculture is a thing btw.

>>7580098
quadcopters are more inefficient than regular helicopters because of the higher disc loading.

>>7575679
Astronaut, because from what we understand.
1. you wouldn't be able to see shit
2. it'd be fucking hot
3. it'd be a one way trip
Oh look a paper on how to send something to the center of the Earth:
http://www.cmp.caltech.edu/refael/league/to-the-core.pdf

Did I mention the part where you'd need to detonate a bunch of nuclear bombs just to break a crack in Earth's crust and send something through

>>7576545
>>7576520
kek. We have not. We have found regions of magma that have a high water content, but they are certainly not oceans.

>>7565071
We should send a lander. A NUCLEAR LANDER! Pic related is a MITEE nuclear engine. It could get to pluto and maybe even send samples back to earth(provided it has system to mine ice, and electrolyze it to make hydrogen, etc, etc)

And it uses uranium which isn't in short supply instead of plutonium!

>>7535611
This is something of a sci-fi trope, in reality, submarines do not make very good spaceships:
http://www.projectrho.com/public_html/rocket/reactionlessdrive.php#id--Submarines_In_Space

>>7533650
Simply put, matter you can program. And by program, we mean able to change the shape, stiffness, porosity, thermal conductivity, acoustic properties, electrical properties, optical properties, on command.

Though most often it refers to self-reconfiguring modular robots. Wherein you make a bunch of really small robots that can hold on to each other and move over each other to transform into different shapes. GIF related should give you a pretty good idea of what this looks like.

If said robots are sufficiently small, you could make something like the liquid metal robot from the terminator movies.

I work in 'programmable matter.' Not the type that involves robots though...

>>7534591
The interesting thing is that current space elevator designs are less energy efficient than rockets, this is because it is inefficient to transmit electricity wirelessly over huge distances(0.5-2%).

Of course if one has two tethers, then one can use the tethers themselves to transfer power, but then you need two tethers!

This is not to say that space elevators are a bad idea, just that making an argument in terms of fuel cost is not sound.

>>7533737
cause you can't always bump up the voltage. You might exceed breakdown voltage or your application might not use that voltage.

higher capacity also means smaller, which is necessary for stuff like cellphones

>>7534150
listen kid, if you really wanna make a pulse laser, get an old abrams tank laser range finder, the type that uses a Nd YAG rod and flash lamp. Shit's like really powerful, like powerful enough to turn metal into a plasma(at a small distance with the appropriate lens not continous operation) and drive that.
more info here:
http://rommet.com/remco/misc/Don's%20Lights/members.misty.com/don/laserssl.htm#sslsy1

>>7530757
>>That's not entirely true.
No it is very true:
http://blogs.scientificamerican.com/guest-blog/helium-hokum-why-airships-will-never-be-part-of-our-transportation-infrastructure/

To answer your question: air pressure at 6,000 feet and air pressure is 81 kPa so air density is 1 kg/m^3.

So this means if you had 1 cubic meter of vacuum you could just lift 1 kilogram of ship.

at this pressure hydrogen has a density of 0.06696 kg/m^3, so if you use hydrogen then you can just lift 0.93 kg per cubic meter of hydrogen.

The interesting thing is gravity really doesn't matter here. Though if you really want flying battleships(you're writing a sci-fi novel aren't you), you should increase the density of the air. If you make your planet have an atmosphere that's like a combination of titan and venus. Dense, at high pressure, but cold so people don't get fried. Admittedly, you'd need to do some crazy world building to find an atmosphere that humans could live in.

To get you started there's this:
http://selenianboondocks.com/2013/11/venusian-rocket-floaties/

empty Rocket stages can pretty much just float on venus.

>>7519978
The truth of the matter is that we can't know what the weapons of the future will be like. Right now the future of war appears to be extreme asymmetric warfare. Instead of wars being fought between nations states, wars might be fought between nation states and random crazed individuals who just want to kill people for no reason.

https://www.wfs.org/Upload/PDFWFR/WFR_Fall2011_Kunstler.pdf

There is no way we can predict what the next big asymmetric threat will be.


>>7520166
>>I've read that the battery technology was increasing exponentially
it most certainly is not.

>>7520540
From what we understand, gravity can behave in analogous manner to electromagnetism. This is known as gravitoelectromagnetism and has been experimentally verified by Gravity Probe B
https://en.wikipedia.org/wiki/Gravitoelectromagnetism

>>7520537
Since you posted a touhou I am obligated to respond.

Ok, so since we know that gravity can behave analogously to electromagnetism, we can construct gravitational analogs of electromagnetic devices.

In electromagnetism, we can make an electric dipole by passing a changing electric current for a toroid.

We can make a gravitational dipole in a similar manner if we pass a changing "mass current" through a toroid. Of course for the effect to be large, one needs a lot of mass moving or ultradense matter. Oh and you need a changing mass current, so all this has to be continuously accelerating or decelerating....

See Robert L. Forward's guidelines to antigravity for more
http://u2.lege.net/culture.zapto.org_82_20080124/antigravidity/Robert%20L.Forward%20-%20Guidelines%20to%20Antigravity.pdf

>>7506864
>>Given all this, I think it's a safe bet to say that the thought and the movement are one - the thought *is* physical movement.
so if you anesthetize nerves going to your muscles, then you would not be able to think?

>>7506832
Neuroscience I think. I did learn about the motor primitives part in one of my robotics classes. I'm just some random autist though.

>>6622061
Good luck printing fissile materials much less obtaining them.

No, there isn't enough Americium in smoke detectors for you to make a bomb.

What's scarier is a future where everyone has a Mr. Fusion that can be modded into an ignitor for a hydrogen bomb.

Good thing fusion is so difficult!

>>6601220
now, there will be no ignoring of me, but you are correct!

There's still quite a bit of physics that needs to be worked out before we can do something even remotely like this.

Breeding/building a balrog, well that's just an engineering problem.

>>6597032
The fuck is the sims 3? Dammit can't you be like ever other nerd and ask about when we're gonna get the replicators from star trek!

We have something almost like that today, called food printing. It's currently only for the culinarily adventurous, but in the near future, it might be what old people eat in nursing homes.

Pic related was supposedly 3d printed, looks pretty tasty right? Well it is, but if you look closer, you'll notice that everything consist of a gel like substance. And that's why they're aiming this at old people, because old people have a hard time eating, but if you can print something pretty, you can supposedly improve quality of life.

what this gel like substance is, is not specified, but it's probably regular food that has been pureed and combined with a gelation agent. It might also be meat combined with yummy meat glue!

http://www.3ders.org//articles/20140530-german-3d-printed-smoothfood-actually-looks-and-tastes-pretty-good.html

Oh and if you want to 3d print some food, here's how to do it!

http://creativemachines.cornell.edu/sites/default/files/69-Lipton-Mutlimaterial%20food%20printing%20Final.pdf

>>6592272
Also, calling that 'skin 3d printed' is a bit tenuous, it's more like just printed skin, as it does not have any layers or 3d dimensional structure.

>>6592272
I don't know what all those abbreviations mean! However, bio-printing is currently still in development, so it's really hard to tell what careers for it might be in the future.

So whatever you do, don't overspecialize and don't specialize in 3d printing(the technology will change)!

Now there's quite a bit of process development that needs to be done to make bioprinting a reality which is going to involve fields as diverse as biomedical engineering, chemical engineering, and mechanical engineering.

However, we may turn out to not need bioprinting. The big thing everyone wants to do with bioprinting is make complex organs, and bioprinting is only one process that might enable us to do this.


We might be to figure out how to grow organs from scratch, or even grow said organ inside a patient's body.

We could figure out how to get cells to self-assemble into the organs we want, again this is one of many potential processes we could use.


TL;DR Don't specialize, bioprinting may become obsolete before it happens

>>6579949
ugh, why would you put a link in an image?

Also, who wants some 3d printing de-hype?

How about the fact that it could get hugely crippled by DRM? Like really bad DRM, built into the hardware.

>>6577498
Ahh, but that's the beauty of it, they aren't weapons until you need them to be.

>>6577478
>>gravity
gravity but no atmosphere, so mass drivers work great!
>Moon not ideal launch platform
Oh yeah, just wait till the US builds a self replicating robot factory that uses railguns to shoot seeds of itself all over the Moon.

Then then US has a huge network of mass drivers they can bombard the earth with, that is unless the chinese build one first!


www.niac.usra.edu/files/studies/final_report/880Chirikjian.pdf

>>6577334
Here have something that is not potato quality.
http://www.niac.usra.edu/files/library/meetings/annual/jun00/433Ignatiev.pdf

>>why
Because some Congressman found out about NTRS, and flipped the fuck out. He went "OMG, Chinese hackers can see all of NASA's SPEHS SEKRITS! SHUT IT DOWN!"

So NTRS was shut down, until all of the SPEHS SEKRITS(which weren't supposed to be secret anyway) were removed.

But NASA, who didn't have any money to comb through >9000 documents for space sekrits, did a really shoddy job, and NTRS has never been the same since.

Of course most of the stuff in NTRS was also published in other journals, so the Chinese could see it anyway.

So in short, the only people prevented from accessing SPEHS SEKRITs are you and me, all because some congress critter hates China.

http://nasawatch.com/archives/2013/05/wolf-and-bolden.html

>>6577272
>>6577280

>>Why haven't we covered the moon in factories yes?
Jimmy Carter wanted NASA to build a self replicating lunar factory in the 80s, but declined when he saw the price tag

See Advanced Automation for Space Missions:
http://www.islandone.org/MMSG/aasm/

It's quite possibly the last thing we'd need to send up to space aside from people.

Coincidentally, some 3d printing-like processes were proposed in it, just imagine if we had actually built it....

But it is more feasible today. In fact we've almost worked out how to PAVE solar cells onto the Moon using lunar regolith!
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20050110155.pdf
How about them apples solar roadways people?


>>6577205
>> I've been trying to put a DMLS printer
I don't want to discourage you, but sintering is hard! Sintering scales with T^4, which means it's really sensitive to small changes in temperature.

You should figure out how to do laser sintering with plastic first. But if you must build your own LS machine, figure out how to monitor the build and correct for errors in real time. If you can do this, you'd make big bucks

>>6577232
>>Also, to all of your doubts on the strength and level of detail on a DMLS printer, this should make you a bit less critical.

I've visited solidconcepts, I've seen the very machine that made the gun, and I'm still not impressed.

Ok I will admit, the sintering process is pretty cool with sparks flying everywhere.

>>you would not need support struts added into the model
Nope, you every much do, anything you print has to be printed onto the metal bed for heat dissipation.

>>post processing
And lots of it too. They probably HIP'd it too. Post processing really limits the usefulness of DMLS

>>level of detail
level of detail isn't the only problem. AM'd parts could have big fatigue problems because of internal porosity and voids, which as of yet we have no economical QA procedures for detecting.

And firing a couple magazines is certainly not enough to demonstrate fatigue properties.

Additive manufacturing still has a ways to go.