posted
Minutiaeman and I have been trying to figure out the density of antimatter as stored on starships and used in torpedo warheads. According to TNGTM, antideuterium is transported as a type of slush. If we assume, for the sake of simplicity, that antideuterium is stored under pressure, what is it's density? At what temperature does deuterium become a solid or slushy liquid?
(Show your work, please).
In a related question (asked previously I think), what's the explosive yield of 1.5 kg of antimatter (in joules or megatons of TNT or both)?
------------------ When you're in the Sol system, come visit the Starfleet Museum
posted
Let me tell you about some of the assumptions I was working with. I figure since antihydrogen would have the same physical properties as normal hydrogen, we can use the same storage specs.
According to the TNG:TM, they store deuterium at 13.8� Kelvin. So my guess would be that they store antimatter at the same temperature.
I was trying to use the Ideal Gas Law to determine either the volume or the amount (measured in moles) of antimatter that could be stored in a photon torpedo. The problem is that we have two variables: volume and pressure.
posted
So far, we have PV = nRT, where r = 0.082056 L*atm/(mol*K). Minutiae tells me that this gives a volume of 1.6851 cubic meters or 1685 liters at 1 atm. This seems a bit high to fit into a warhead and is still probably a gas (since it's less than 1% of the weight of water at room temperature). So, this means that the deuterium has to be under pressure. A pressure of 1000 atm would get that down to 1.6 liters, which seems like a nice little package, but is the pressure to high for safety?
------------------ When you're in the Sol system, come visit the Starfleet Museum
------------------ Star Trek Gamma Quadrant Average Rated 8.32 out of 10 Smileys by Fabrux (with seven eps posted) *** "Oh, yes, screw logic, let's go for a theory with no evidence!" -Omega 11:48am, Jan. 19th, 2001 *** Card-Carrying Member of the FlareAPAO *** "I think this reason why girls don't do well on multiple choice tests goes all the way back to the Bible, all the way back to Genesis, Adam and Eve. God said, 'All right, Eve, multiple choice or multiple orgasms, what's it going to be?' We all know what was chosen" - Rush Limbaugh, Feb. 23, 1994.
posted
By the way, we've also assumed that 1.5 kg of hydrogen is 1488.1 mol. That gives V (liters) = 1488.1 mol x 0.082056 L*atm/(mol*K) x 13.8 K = 1685 liters or 1.685 cubic meters. But I was wondering if antimatter is stored as antideuterium (that has an atomic weight of 2). Would that double the weight? I'm not up on the molecular forms of hydrogen isotopes.
------------------ When you're in the Sol system, come visit the Starfleet Museum
[This message has been edited by Masao (edited May 08, 2001).]
posted
Wait, under what impression is it that you think slush deuterium is a gas? I mean, if you have an explanation by all means, but "slush" in my mind means liquid. And at 13 K or whatever? That's really cold. Probably liquid. In which case you can't use PV=NRT, I'm afraid.
------------------ "A celibate clergy is an especially good idea because it tends to suppress any hereditary propensity toward fanaticism."
posted
Yes, I didn't know how to handle this phase change. Antideuterium is supposedly stored as a semiliquid/semisolid slush. So how do we calculate this properly? Any rocket scientists here with experience with liquid gases? Anyone with a LPG tank beside their house?
------------------ When you're in the Sol system, come visit the Starfleet Museum
quote:Wait, under what impression is it that you think slush deuterium is a gas? I mean, if you have an explanation by all means, but "slush" in my mind means liquid. And at 13 K or whatever? That's really cold. Probably liquid. In which case you can't use PV=NRT, I'm afraid.
Crap crap crap crap crap! That is so obvious, it's stupid!
posted
What you need to do is find the density of liquid hydrogen. Fluids are very difficult to compress, so the density of liquid hydrogen would be about the same at any pressure, assuming 1 atm. And (anti)deuteriun has an atomic mass of 2 since it's got a (anti-)proton and a (anti-)neutron. Just double the density since you now have twice the mass.
Take that info, and the fact that the density of solid deuterium would be slightly higher than the liquid since most liquids are slightly less dense than their solids. (Water being a notable exception.)
Also, when a solid melts, it will stay at it's melting point until it is completely liquid. So, increase the density of deuterium ever so slightly and you'll probably have a pretty close number to what it's density would be.
Some sice notes: According to my research, hydrogen melts at 14 K, and since deuteruim is heavier, I would assume it's melting point is a little different. So 13.8 K sounds right.
Also, the ideal gas law is pretty much worthless in this temp range. You would need the van der Waals equation:
posted
Ideal Gas Law are only meant for gas in an "ideal" situation.
"IF" antihydrogen have similar properties as hydrogen the we assume it exist in a gaseous form in its' nature state. However, in StarTrek, antihydrogen is stored in a liquid form (hence, slush). Ideal Gas Law can be be apply because the "gas compressibility" does not remain as a constant 1 or close to constant of 1 in extreme environment(curve line, instead of a straight line graph) but decrease or increase with different condition.
Different gas laws have to be applied.
Damn, I feel like a geek!!!
------------------ What is the difference between a terriorist and your girlfriend? - With terrorist, there is a chance of negotiation.
posted
Okay, with all the math: 1=1 What is the density of slush hydrogen?? There is your answer...
------------------ "One's ethics are determined by what we do when no one is looking" Nugget Star Trek: Gamma Quadrant Star Trek: Legacy Read them, rate them, got money, film them
"...and I remain on the far side of crazy, I remain the mortal enemy of man, no hundred dollar cure will save me..." WoV
posted
Deuterium is just like hydrogen. So it's a gas at room temp. Heavy water is just regular water, but with two deuteriums instead of hydrogens. It's about 10% heavier than regular water.
P.S. FYI: I have a bachlor's degree in chemistry.
------------------ It doesn't matter if you don't know what you're doing as long as you look good doing it.
Printer-friendly view of this topic
