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Comment Re:sunfire / in my stellerator / makes me... happy (Score 1) 94

So on average the fission reactor material only has about 10% of its atoms displaced over the lifetime, while the fusion reactor would have, on average, every atom displaced hundreds of times over the lifetime.

How can you make generalized statements like that? Cross sections vary by many orders of magnitude Fission reactors are generally made of steel, which is hardly setting any records in terms of low cross sections. The smaller the reactor, the less material you have to replace, and the more expensive the material you can use. And being "displaced" is not a fundamental universal material property effect, it depends on how the material responds to radiation damage, which varies greatly. Generally materials respond better at high temperatures (annealing), and fusion reactors operate of course at far higher temperatures than fission reactors.

I have trouble seeing how one would consider neutrons per square meter to matter more than neutrons per MeV. Because neutrons determine what you're going to have to replace, and energy determines how much money you get from selling the power to pay for said maintenance. You can spread it over a broad area and do infrequent replacements, or have it confined to a tight area and do frequent replacements, the same amount of material is effected. Some degree of downtime for maintenance is normal in power plants - even "high availablility" fission plans still only get ~85% uptime.

Comment Re:Power efficiency is good in some places, not al (Score 1) 281

John Cook (put his blog in your RSS feed if you don't already have it) made a very good point recently: The speed gains from Moore's Law are dwarfed by the speed gains from algorithmic improvements. And unlike Moore's Law, we're not yet seeing a limit approaching for better ways to solve stuff. The post in question: http://www.johndcook.com/blog/...

Comment Re:Power efficiency is good in some places, not al (Score 1) 281

A lot of tasks intrinsically don't scale, or scale only up to some limit. Some people are running into this already in the HPC world, were we have big parallel machines that they can't take full advantage of. Their simulations simply don't scale above a certain number of cores.

This problem is becoming steadily worse, since people want to make models with more detail (that tends to not parallelize well), and simulate much longer timeframes than before. If you're simulating protein interactions over one millisecond, then it might not matter if it takes an hour or two. But if you want to use that to understand LTP in neurons and simulate a second or two, then it becomes a very major problem if your model can't parallelize further and the per-core speed stays put.

Comment Re:last chance to buy quality Sharp products (Score 2) 40

Geeks are just as good the world over, whether Japan, Taiwan, EU, US or China. Product quality has nothing to do with the quality of the designers and builders and everything to do with the budget and time constraints they have to do their stuff. And that is all about where their company wants to position itself in the price/quality/reputation landscape.

Sharp has a well-deserved reputation for good quality and sometimes off-beat or niche products that delight a few even if they don't become huge sellers. And that's of course part reason why they've been in trouble for some years now. Foxconn doesn't have a reputation for premium products or for doing their own thing.

I share the worry that Sharp as we know it will disappear, and just become another nameplate pasted on bland, forgettable me-too stuff.

Comment Re:Two opposed postions on abortion, both libertar (Score 1) 422

No. It would make them sentient dolphins, not "non-human people".

Whatever you want to call them - do you think that they would not be entitled to, at the minimum, a right to life to the same degree as humans (i.e. killing them should be treated as murder)?

If so, then what determines who has that right and who doesn't? Sentience? But zygotes aren't sentient.

Easy peasy!

23 chromosomes is a normal number for humans, but not all humans have 23 chromosomes - Down syndrome, XYY males and XXX females etc.

Ultimately, all this is just accumulated mutations and selection of them over the course of that 6 million years of divergence. By itself, that's still a quantitative difference, not qualitative - i.e. we know that things are different, sure, but they're also different between humans on genetic level. The question is, what exactly about those missing or extra chromosomes and DNA difference is responsible for having or not having natural rights? If you could incrementally edit a chimp's genome to make it human, at which point during the process is it "human enough"?

Comment Re:sunfire / in my stellerator / makes me... happy (Score 1) 94

Hmm, thought... and honestly, I haven't kept up on fusion designs as much as I should have... but has there been any look into ionic liquids as a liquid diverter concept? In particular I'm thinking lithium or beryllium salts. They're vacuum-compatible, they should resist sputtering, they're basically part of your breeding blanket that you need already... just large amounts, flowing, and exposed. Do you know if there's been any work on this?

Comment Re:sunfire / in my stellerator / makes me... happy (Score 2) 94

The plasma facing material faces a flux of 1 neutron per 17,6Mev. By contrast, nuclear fuel cladding faces a flux of ~2,5 neutrons per 202,5 Mev, or 1 per 81 MeV. It's certainly higher, but it's not a whole different ballpark. And yes, you're dealing with higher energy neutrons but in a way that can help you - you've often got lower cross sections (for example), and in most cases you want the first wall to just let neutrons past.

There's a number of materials with acceptable properties. Graphite is fine (no wigner energy problems at those temperatures). Beryllium is great, and you need it anyway. In areas where the blanket isn't, boron carbide is great. Etc. These materials aren't perfect, but they're not things that get rapidly "converted into dust" by neutrons. Really, it's not the first wall in general anyway that I'd have concerns about, it's the divertor. The issue isn't so much that it takes a high neutron and alpha flux and "erodes" fast - that doesn't change the reactor's overall neutrons per unit power output ratio, and if you have a singular component that needs regular replacement, said replacement can be optimized. The issue is that you have to bear such an incredible thermal flux on one component. Generally you want to spread out thermal loads, it makes things a lot easier.

Comment Re:Two opposed postions on abortion, both libertar (Score 1) 422

Anyone intelligent enough to post on /. is intelligent enough to know that half the DNA isn't enough.

Enough for what? To eventually grow a human, sure. But to be a person? I don't know.

Thus, if self-awareness is the measure of humanity/personhood, it's just as ok to "put down" an eighteen month old human as it is to kill an unwanted dog.

You're correct - i.e. logically speaking, either both are okay, or neither is okay.

Or, possibly, the definition of "person" is more extensive than self-awareness. But I still don't see why it should have anything to do with DNA makeup.

I fail to see the difference between the two.

It's because the definition of "person" is not strict, and for most people who haven't given it consideration, it's basically "I know it when I see it". However, surely you can imagine a hypothetical non-human person, even under whatever subjective definition you subscribe to? E.g. suppose we do determine that dolphins are "intelligent enough", after all, and devise means to communicate with them with a full-fledged language - would that not make them persons?

"Human", on the other hand, is defined entirely in strict biological terms. It's still not a strict definition if you consider corner cases (which extinct hominids were human and which weren't, for example? and at which point the result of our future evolution can no longer be called "human" and becomes a different species?), but for practical purposes, you can just do a DNA test.

Where did I indicate such a thing???

You indicated that natural rights belong to humans, and humans are defined by DNA. I don't see why such differentiation by DNA is fundamentally different from differentiating within homo sapiens sapiens by DNA; the only difference is degree. Just as you can determine the difference between humans and chimps by comparing their genes, so you can determine the difference between different human populations by looking at some genetic markers or others (and yes, there are some that correlate pretty well with black skin, for example).

And don't pretend like the fact that one case straddles species boundary and the other one doesn't makes a huge difference - "species" themselves are a rather arbitrary human construct stemming from our desire to neatly label and categorize everything, but nature doesn't really care about such things. If you want to talk about objective facts, you'll have to show a difference in quality rather than quantity of differences (or demonstrate that some quantity is a threshold meaningful for some reason other than "because I said so").

It is relevant, because with it you boil the argument down to objective facts instead of philosophical and socio-political arguments.

You can't boil the argument down without agreeing on what the argument is about. This particular one is whether personhood or humanity is the defining factor for possessing natural rights, including right to life. Yes, if you arbitrarily resolve this question in favor of humanity, then you can boil it down to objective facts - DNA etc. But that first decision is arbitrary, and not everyone agrees to it.

Comment Re:Fusion energy is impractical (Score 1) 94

When a fast neutron hits an atom it knocks it out of its position and frequently changes it to a different element/isotope.

The same applies to slow neutrons, so....? Your average 14,1 MeV neutron is most likely to inelastic scatter down to the point where more exotic reactions than (n, gamma) are basically impossible (excepting a few specific cases, like 6Li(n,t)4He - again, not dangerous). Only a small percentage of your 14,1MeV neutrons (depending on the material they're passing through) have a chance of undergoing anything more than a standard (n, gamma) transmutation. Unless the system is specifically designed to cause that (for example, a beryllium multiplication in the lithium blanket). The standard case is inelastic scatter once or twice -> elastic scatter a bunch -> become partially or completely thermalized -> capture.

This turns a solid structural material into a radioactive powder

What happens depends entirely on what's being bombarded. Many materials are perfectly fine after long periods of exposure - slow or fast neutrons. Light ions in particular are usually either A) relatively unaffected (sometimes requiring sufficient heat for proper annealing, sometimes not), or B) incredibly good absorbers, leaving nothing dangerous behind. See a more detailed breakdown above.

Comment Re:Huh? (Score 2) 230

People don't tend to stay at those places long, but if you haven't been able to get other work it can help pay bills until you can.

Swiping wallets from tourists at a busy attraction can also help you pay the bills until you can, but I don't think that's a valid argument in favor of the person doing so.

Comment Re:Two opposed postions on abortion, both libertar (Score 1) 422

Answer, part #1: Because the the human brain develops naturally from that zygote.

Sure, but why start with zygote? Why not the egg? Why not before? Any point in this chain is pretty arbitrary, and even if you pick one (like you did with "has its own DNA"), it's not clear what it has to do with personhood.

Answer, part #2: Babies with severe microcephaly have no self-awareness, but are still humans.

Sure. And it's a valid question to ask whether they should have the same rights as a self-aware human being. Ditto for braindead people.

Because their DNA is not human.

But then you're not basing your definition of rights on whether someone is a person or not. You're basing it on whether they're human or not (or rather - because there isn't really a hard delimiter between species in general - on whether someone is "sufficiently human"). I don't see why this is, in principle, any better than denying on a scattering of other genetic markers that correspond to dark skin etc.

Biology is irrelevant here, because it does not really concern itself with issues such as "personhood" and "natural rights".

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