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Sure, I can easily imagine that by mentally substituting steel with jello - at some point you're tear it apart no matter how thick the walls are. However, that substitute also gives me the impression that most shapes we would normally consider for a vessel don't reach the maximum strength possible for the material.
Most vessels are spherical or cylindrical, which is already pretty good (intuitively, spherical vessels should be optimal for isotropic materials). You might want to take a look at the mechanics of thin-walled pressure vessels if you didn't already.
It's important to note that the radial stresses in cylindrical vessels are way smaller than the axial and hoop stresses (which, so to say, pull perpendicular to the "direction" of the pressure). This is also why wound fibers can increase the strength of such vessels.
In response to
Even better cryonics – because who needs nanites anyway?
Thanks for taking the time to write this up and putting numbers to things: it makes it actually possible to evaluate your idea critically.
The thing that jumped out at me was the amount of pressure required for human preservation. What kinds of devices can generate 100KBar of pressure?
Edit: changed GBar to KBar
Materials science undergraduate student here (not a mechanical engineer, my knowledge is limited in the area, I did not go to great lengths to ensure I'm right here, etc.).
A typical method to generate high pressures in research are diamond anvils. This is suitable for exploring the behavior of cells and microorganisms under high pressure.
For human preservation, however, you'd need a pressure vessel. As the yield strength of your typical steel is on the order of 100, maybe 300 MPa, you're really up against a wall here, materials-wise. I don't doubt that suitable alloys for human-sized pressure vessels at 350 MPa exist, however, such vessels will be expensive, and controlling processes within will be difficult. In any case, generating such pressures will probably not involve a moving piston.
I can't really tell whether or not the procedure you've outlined is viable, but I'm quite sure it's far from trivial, just from an engineering point of view.
The concerns of user passive_fist are also valid.
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Open Thread, Apr. 06 - Apr. 12, 2015
I think I’ve found a somewhat easy-to-make error that could pose a significant existential risk when making an AGI. This error can potentially be found in hierarchical planning agents, where each high-level action (HLA) is essentially its own intelligent agent that determines what lower-level actions to do. Each higher-level action agent would treat determining what lower-level action to do as a planning problem and would try to take the action that maximizes its own utility function (if its a utility-based agent) or (if it’s a goal-based agent) probability of accomplishing its goal while minimizing its cost function (UOCF).
For these agents, it is absolutely vital that each HLA’s UOCF prevents the HLA from doing anything to interfere with the highest-level action maximizing its utility function, for example by rewriting the utility function of higher-level actions or sending the higher-level actions deliberately false information. Failing to do so would result in an error that could significantly increase existential risk. To explain why, consider an agent whose highest-level action wants to maximize the number of fulfilling lives lived. In order to do this, the agent has a lower-level action whose goal is to go to a warehouse to get supplies. The cost function of this lower-level action is simply a function of, say, the amount of time it takes for the agent to reach the warehouse and the amount of money spent or money in damages done. In this situation, the lower-level action agent might realize that there is a chance that the higher-level action agent changes its mind and decides to do something other than go to the warehouse. This would cause the lower-level action to fail to accomplish its goal. To prevent this, this lower-level action may try to modify the utility function of the higher-level action to make it certain to continue trying to go to the warehouse. If this is done repeatedly by different lower-level actions, the resultant utility function could be quite different from the highest-level action’s original utility function and may pose a large existential risk. Even if the lower-level action can’t rewrite the utility function of higher-level actions, it may still sabotage the higher-level action in some other way to further its own goals, for example by sending false information to higher-level actions.
To prevent this, the utility function of the lower-level action can simply be to maximize the highest-level action’s utility, and it can see the UOCF it was provided with as a rough method of maximizing the highest-level action’s utility function. In order to make the UOCF accurately represent the highest-level action’s utility function, it would (obviously) need to place high cost on interfering with the highest-level action’s attempts to maximize its utility. Some basic ideas on how to do this is for there to be very high cost in changing the utility functions of higher-level actions or giving them deliberately false information. Additionally, the cost of this would need to increase when the agent is more powerful, as the more powerful the agent is, the greater damage a changed utility function could do. Note that although higher-level actions could learn through experience what the UOCFs of lower-level actions should be, great care would need to be taken to prevent the AGI from, when still inexperienced, accidentally creating a lower-level action that tries to sabotage higher-level actions.
Please insert some line-breaks at suitable points to make your comment be more readable. At the moment it's figuratively a wall of text.
Edit: Thank you.
I don't know what this means :(
If you make a joke on a day where jokes are made, but another person is not on the same day anymore, that person might not get the joke because they don't think the day matters.
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Thinking well
I hate april fool's jokes across time zones. You don't expect them on April 2nd, do you?
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Harry Potter and the Methods of Rationality discussion thread, March 2015, chapter 121
Ah, I see :)
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Harry Potter and the Methods of Rationality discussion thread, March 2015, chapter 121
Although honestly, what kind of idiot had the idea to order the date mm/dd/yyyy?
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Don't estimate your creative intelligence by your critical intelligence
I did post this to Discussion. And, I'm sorry to be so blunt, but why do you expect me to take orders from someone named Username with a total karma of 720? I've been a significant contributor to this site, and you have not. Go police somebody else.
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Don't estimate your creative intelligence by your critical intelligence
(paying a karma toll for this)
The username "Username" with password "password" can be used by anyone wishing to stay anonymous.
The following would be a better argument, IMO:
No, it wouldn't, because you are presupposing that one already understands why one would want to do such a difficult thing. The whole point of pointing out the implications of acceleration in mortality is to point out real mortality rates can imply very long lifespans and that squaring the curve would have major and desirable implications. Only once the potential benefits have been established does anyone care about how feasible fixing it would be. There are two blades to the idea of 'cost-benefit', and you are dismissing out of hand anyone even trying to roughly estimate the latter.
To use your atom example:
Right now, our power sources like coal and oil produces X joules per gram; but we can see by simply calculating E=MC^2 that the potential energy of somehow tapping into mass-energy conversion rather than normal chemical potentials would generate multiple orders of magnitude more energy than from normal strategies. This is tantalizing and even believable.
And someone else replying:
That's just not how the relevant model works. Thusly, I don't think the arguments brought forth are good enough to warrant the claim that atomic energy is possible.
Go back to the original article. Why are they discussing aging at all? To justify research like Calico into reducing it.
Jeez. Talk about missing the point.
The following would be a better argument, IMO: No, it wouldn't, because you are presupposing that one already understands why one would want to do such a difficult thing. The whole point of pointing out the implications of acceleration in mortality is to point out real mortality rates can imply very long lifespans and that squaring the curve would have major and desirable implications.
Making up numbers is not the way to do this, then. If you want to introduce people to the idea that very long and healthy lives are possible and desirable, a historical perspective would be good. Or you could discuss how we lead relatively healthy lives until about 60, and then somehow the decay kicks in - which is really a shame because we've been healthy for so long, and there shouldn't be a moral reason why it can't stay this way.
Only once the potential benefits have been established does anyone care about how feasible fixing it would be. There are two blades to the idea of 'cost-benefit', and you are dismissing out of hand anyone even trying to roughly estimate the latter.
No I'm not. I agree that living happily ever on would be an enormous win for most humans. And if the author must, they are free to write fiction on how much better the world would be.
Additionally, my point is not that it's ultra-mega-hard to extend the human lifespan, and that we shouldn't even try. But we have to take into account how the system actually works, and then start from there. That is, we have to build a model, then see if we can improve the situation (i.e. extend human lifespan to 1000 years) by varying parameters within the model.
If that's not possible (it's not possible if mortality follows a doubly-exponential curve with a hard cutoff around X years, where X might be extended by 50% - if things go well), we go see if we can circumvent the model, so that it doesn't apply anymore. Blood donations might be a stab at this. Calorie restriction isn't.
To use your atom example:
Right now, our power sources like coal and oil produces X joules per gram; but we can see by simply calculating E=MC^2 that the potential energy of somehow tapping into mass-energy conversion rather than normal chemical potentials would generate multiple orders of magnitude more energy than from normal strategies. This is tantalizing and even believable.
There's a difference between this, and the original writing. You already have a good reason why the real energy content of matter should be way higher than it appears to be. The only grounds on which someone would reply to this
That's just not how the relevant model works. Thusly, I don't think the arguments brought forth are good enough to warrant the claim that atomic energy is possible.
would be that the author of the piece on E=mc^2 then goes on discussing various techniques to increase the energy output of coal burning, perhaps using a novel oxidizer or special reaction conditions. That would be silly, after one has understood why chemical potential energy is so limited.
But, in a way, the author of the original article does exactly this by discussing the impact of various drugs or treatments like calorie restriction. Only that the limits set by the Gompertz model - not the parameters, but the model - and a way to overcome the Gompertz curve - are not discussed.
I have a feeling that I don't understand your point or how it relates to mine, or that I don't see that you would understand my point.
Also I'm getting a hostile vibe from your reply, so while you may answer and I will read your answer, I won't reply to that anymore as this kind of stress negatively impacts my expected lifespan.
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Theoretically, zero. However you're right that the structural demands of maintaining pressure over long term (and, especially, maintaining cryogenic temperatures and high pressures at the same time) are high and there is a large risk of unintended pressure release.
There's also leakage by diffusion of gasses, which might be non-negligible due to the high pressure gradient, although the diffusion coefficient e.g. of water through steel should be low. Not sure how that works out.