Science questions not worth a thread I: I'm a moron!
- Thread starter The Imp
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You have 46 chromosomes, but they're paired up in sets. Each chromosome is very similar to its pair, but not exactly the same, no. So normally you'll hear Chromosome 1 but that's actually a set of very similar chromosomes.
hobbsyoyo
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The same as would be lethal on earth. 1.5 bar might as well be 1 bar for your purposes. I can look up the lethal concentration of CO2 but IIRC it's like 2%.
Oxygen can cause you problems but it's generally not lethal in any quantity that's realistically found in an atmosphere. Oxygen is so reactive that at harmful concentrations it'll react itself out of the atmosphere and lower the concentration. Also there would be out of control fires which are a subset of the last sentence.
Oxygen can cause you problems but it's generally not lethal in any quantity that's realistically found in an atmosphere. Oxygen is so reactive that at harmful concentrations it'll react itself out of the atmosphere and lower the concentration. Also there would be out of control fires which are a subset of the last sentence.
As it is the partial pressure that count, that 1.5 bar lower the deadly concentration by 2/3. So its more like 1.3% instead of 2%.
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Ripping this from wiki:
Adaptation to increased levels of CO2 occurs in humans. Continuous inhalation of CO2 can be tolerated at three percent inspired concentrations for at least one month and four percent inspired concentrations for over a week. It was suggested that 2.0 percent inspired concentrations could be used for closed air spaces (e.g. a submarine) since the adaptation is physiological and reversible. Decrement in performance or in normal physical activity does not happen at this level.
I think uppi is right about the pressures. Toxicity is about how much CO2 you're breathing in, not its ratio to oxygen or other gasses.
Adaptation to increased levels of CO2 occurs in humans. Continuous inhalation of CO2 can be tolerated at three percent inspired concentrations for at least one month and four percent inspired concentrations for over a week. It was suggested that 2.0 percent inspired concentrations could be used for closed air spaces (e.g. a submarine) since the adaptation is physiological and reversible. Decrement in performance or in normal physical activity does not happen at this level.
I think uppi is right about the pressures. Toxicity is about how much CO2 you're breathing in, not its ratio to oxygen or other gasses.
The rate at which your lung can exchange gases in your blood with the air depends on the partial pressure of that gas. So the point where it is unable to breathe away the CO2 in your blood fast enough is at a certain partial pressure and not at a certain concentration.
Other effects of the higher pressure are unlikely to be relevant at this moderately increased pressure, so just scaling the toxic concentration inversely with the pressure is a good approximation.
Other effects of the higher pressure are unlikely to be relevant at this moderately increased pressure, so just scaling the toxic concentration inversely with the pressure is a good approximation.
PlutonianEmpire
King of the Plutonian Empire
I like the palindrome in the post number above. 
Anyways, what are the current (leading?) theories for in situ formation of close binaries (such as two sunlike stars in close orbit; less than 0.5 AU)? Can anyone point me to good info on such, if it exists?
Anyways, what are the current (leading?) theories for in situ formation of close binaries (such as two sunlike stars in close orbit; less than 0.5 AU)? Can anyone point me to good info on such, if it exists?
Disgustipated
Deity
Not sure if this has been asked in this thread, but someone explain 3D printing to me. I read the wiki entry, but one thing I didn't see mentioned is what material they use to "make" objects. I'm confused on this part. You can't make something out of nothing right? The news articles make it seem like something out of Star Trek. I keep seeing news articles about it, but they don't say how the "objects" are specifically created. You can't make an object out of ink. I'd imagine plastics would be fairly easy, but how can you put metal atoms on top of each other? I heard that one day they could even manufacture guns using this process. How? How can you put metal atoms on top of metal atoms? Where do they come from? How are they stored? How do the atoms flow from one place to another? Don't tell me they are created out of nothing.
It's a plastic powder and glue binder.
Instead of printing in 3D, think of it like printing in 2D thousands of times. A layer of powder gets bonded together by coloured glue, and then another layer is glued together and to it on top of it.
Instead of printing in 3D, think of it like printing in 2D thousands of times. A layer of powder gets bonded together by coloured glue, and then another layer is glued together and to it on top of it.
Most commercially available 3D printers use plastic as raw material.The plastic is stored similar to hot glue, in its solid form. When printing it is heated and the semi liquid plastic is forced through a nozzle on to a plate.
The trick is using a material that cools fast enough so it wont sag after it leaves the nozzle.
As for guns maybe using some kind of ceramic material would be feasible.
Also you're not really putting atoms on atoms, the scale at which 3D printers work are too big for that. You can put metal atoms on top of each other with an electron microscope. They'll even form nicely ordered structures. But the objects "build" are tiny.
The trick is using a material that cools fast enough so it wont sag after it leaves the nozzle.
As for guns maybe using some kind of ceramic material would be feasible.
Also you're not really putting atoms on atoms, the scale at which 3D printers work are too big for that. You can put metal atoms on top of each other with an electron microscope. They'll even form nicely ordered structures. But the objects "build" are tiny.
Bluemofia
F=ma
For metal, I believe it is similar to arc-welding layer after layer of metal powder to the correct shape. I recall them designing new spongy/porous engine blocks that are much more efficient at cooling, and are impossible to build in traditional methods.
Samez
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You can either use some kind of powder and sinter it in layers (for example with a laser) or you can go the indirect way and infiltrate some polymer based 3d structure made with an 3D Printer with silicon and sinter it afterwards (This way you would get some kind of SiC ceramic).
3D Printing is nice for creating prototypes and demonstrators and stuff like that, but the mechanical strength is very limited. This is the result of them being constructed by layers while each layer will create some kind of phase boundary/weakness.
3D Printing is nice for creating prototypes and demonstrators and stuff like that, but the mechanical strength is very limited. This is the result of them being constructed by layers while each layer will create some kind of phase boundary/weakness.
Disgustipated
Deity
yeah that's what I would think. I can't imagine it would be as strong as subtractive processes (machine down an item).
I'm waiting for the food printer so I never have to cook again: http://money.cnn.com/2011/01/24/technology/3D_food_printer/index.htm
HardRocker
Student.
I don't know if this is worth it's own thread, so I'll just put it here...
Does anyone know what a hydrogen fuel cell is? And if they do, is it an efficient power source?
Does anyone know what a hydrogen fuel cell is? And if they do, is it an efficient power source?
A fuel cell generates electricity directly from a chemical reaction of some fuel (usually hydrogen and oxygen) without burning it. It releases the same energy as a combustion of the fuel but mostly into electricity instead of heat. So it has the same function as an internal combustion engine hooked up to a generator.
Because it converts the chemical energy directly into electricity without converting it into heat first, it is not limited by the thermodynamic limits for converting heat into electricity and can reach higher efficiencies for the conversion.
Like any engine, it is not a power source per se, but converts the energy stored in the fuel into usable electric energy. So if you want to draw power from it, you need to supply it with fuel that needs to be generated or mined somehow.
Because it converts the chemical energy directly into electricity without converting it into heat first, it is not limited by the thermodynamic limits for converting heat into electricity and can reach higher efficiencies for the conversion.
Like any engine, it is not a power source per se, but converts the energy stored in the fuel into usable electric energy. So if you want to draw power from it, you need to supply it with fuel that needs to be generated or mined somehow.
HardRocker
Student.
Is it a reliable replacement for fossil fuels? I mean, it sounds like you could just run it on water if you had the capability to split it into it's perspective components then run it through a PEM or whatever you have to do, right?
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