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Comment Re: how is this relevant to /. (Score 1) 300

There's one strong Android player today. But there could have been two strong players, one of them being Nokia, had they tried entering that market. All those other Android players didn't have the reputation and cachet that Nokia had. Everyone always raved about the hardware quality on Nokias, even with their Lumias running Windows Phone, they just didn't like the software. No, it might not have been a slam-dunk success, it might not have ended well, but those are suppositions. I think it would have turned out a lot better than how it really did with WP. Nokia had a brand cachet that no one smartphone maker had, not even Samsung, which would have been incredibly valuable in western nations, especially Europe. But they didn't offer Android so everyone dumped them and went to various Asian phone makers (Samsung, HTC, LG, Sony) because those companies gave them what they wanted.

Comment Re:How is this newsworthy? (Score 1) 287

You don't have any natural rights to be free from tigers or from gravity. But you DO have the natural expectation that another rational being will understand that if they attack you, they are waiving their own claim on living peacefully. That you don't grasp this is pretty amazing, really.

You'll find that your idea of "rights" disappears quite quickly as soon as any functioning society breaks down.

My "idea" of rights exists at any scale and under any circumstances. That's the entire point. Irrational people do indeed look to take advantage circumstances in which they feel willing to take the chance that their use of violence will go unchallenged because of unpleasant or unexpected circumstances. Which doesn't change the fact that they lose their claim to life when they deny you yours. That's the right you naturally have: to use (or have used on your behalf) the violence necessary to defend your life. Why? Because rational people don't kill other people except in self defense. Those who initiate the violence waive their rights to live in peace.

You're confusing having a right with happening to have the power to defend it at some particular time. These are not the same thing.

Comment Re:sunfire / in my stellerator / makes me... happy (Score 1) 97

Fast neutron cross scattering sections in the couple MeV range barely vary over more than the range of 1-10 barns

1-10 barns is, of course, by definition, an order of magnitude. There is a massive difference between 10 barns and 1 barn. Tenfold, to be precise. ;)

More to the point, you can't just combine all cross sections like that. The energy imparted from an elastic collision isn't the same as from an inelastic collsiion, which isn't the same as an (n, gamma), and so forth. Elastic collisions are particularly low energy, particularly the higher Z the target. Taking them out of the equation yields much greater differences between materials in the range of a couple MeV. The upper end of the neutron energies are "somewhat" similar (up to about one order of magnitude), but down below 6 or 7 MeV or so there's quite a few orders of magnitude difference.

Likewise, total cross sections have no bearing on the accumulation of impurities in the material. The particular cross sections are relevant not only in terms of reaction rate, but also what sort of impurities you tend to accumulate and what effect they have on the properties of the material. Which of course varies greatly depending on what exactly they are.

Integration of annealing cycles into blanket design is not brought up enough in some design studies, but is a consideration to help

It's not a side issue, it's a fundamental issue to the design of a material designed for high temperature operation under a high neutron flux.

Blanket design is extremely constrained by tritium breeder ratio to ensure more tritium is produced than used, which squeezes volume allowed to be used by coolant, ... but they have much lower neutron flux to worry about. Gen 4 reactor designs are in the 500-1000 C temperature range, exceeding in some cases what is thought reasonable for fusion blanket design. ... Blanket replacement is considerably more complex than fuel replacement in a fission reactor

Perhaps they've been heading in a different direction since I was last reading on the topic, but I was under the impression that a prime blanket material under consideration was FLiBe. Which operates in a temperature range of 459-1430C, and is its own coolant. That doesn't change what the first wall has to tolerate, but as for the blanket itself, you have no "structural properties" to maintain, and cooling is only limited by the speed that you can cycle it.

The last paper I read on the subject also suggested that for breeding purposes one needs not only beryllium (they were reporting really poor results with high-Z multipliers), but the optimum ratio (to my surprise) worked out to be significantly more beryllium than lithium. So building structural elements out of beryllium serves double purpose, you don't have the excuse of "I need to use steel because it's cheaper" - you need the beryllium either way. It's strong, low density, similar melting point to steel, but retains strength better with heat, and highly thermally conductive. Beryllium swelling from helium accumulation stops at 750C+ as helium release occurs. So pairing a beryllium first wall with a FLiBe-based blanket seems like a very appropriate option.

Please don't get me wrong, I'm not at all disputing the great amount of engineering work left to do. I'm just more optimistic that appropriate solutions will be found. Perhaps I'm just naive in that regard ;)

Comment Re:Telemetry confirmed? (Score 1) 458

>Has anyone analyzed the data being sent? Or is this a big assumption?

That's a good question, but I think that a better one is why is Microsoft not coming clean about all this or addressing the issue people are having with it that their monopoly OS is doing things that the user isn't fully informed about or have any choice in, or control over.

Microsoft could clear all this up in a moment.

Comment Re:How is this newsworthy? (Score 1) 287

Exactly, because in the jungle there are no rights

Oh, I get it now. You think that human beings aren't any different in their cognitive abilities, capacity for reason, and ability to think abstractly and communicate than are, say, tigers or lemurs.

I don't need it, but I need a government to tell others that.

No, you can tell them yourself, and if they are too irrational to digest the concept, and you're too weak to defend against violent, irrational people, then you need a government to help you protect your rights.

Comment Re:Stupid design (Score 3, Informative) 122

The second one is the device is dropping voltage and consuming power. In standard USB with 500mA at 5V, if the MOSFET takes 1V, that's half a watt of power you're losing in the transistor. (And really, you just use a diode). USB-C with up to 100W, you're looking at losing a lot of power in your reverse protection components.

100% wrong.

The MOSFET is not a diode. Diodes DO cause a 0.6-1V drop. That's why they use a MOSFET instead here in applications where a diode drop is too much. The MOSFET only drops as much as its internal Ron on-resistance allows. For a high-grade MOSFET, that can be in the single milliohms, so it's effectively a dead short. Cheapo MOSFETs are still in the low tens of milliohms. So with 3A of power, that's 1/4W with a crappy 30mohm MOSFET, or 72mW with one with a 8mohm on-resistance. The only reason you'd leave this out if reverse polarity is at all possible is cheapness.

Comment Re:sunfire / in my stellerator / makes me... happy (Score 1) 97

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.

Verizon

Verizon's Mobile Video Won't Count Against Data Caps -- but Netflix Will (arstechnica.com) 103

Earthquake Retrofit writes: Ars Technica has a story about how Verizon Wireless is testing the limits of the Federal Communications Commission's net neutrality rules; Verizon has announced that it will exempt its own video service from mobile data caps—while counting data from competitors such as YouTube and Netflix against customers' caps.

Comment Re:How is this newsworthy? (Score 1) 287

So you think that just because you decided to kill them, they didn't have the right to live? That's really your take on things?

If you initiate violence, you are giving up your OWN claim on your right to live. You have the right up until you infringe on someone else's. That's simple, rational stuff. If you can't use reason in your world view, then you are by definition looking at things irrationally. If you act irrationally, and it results in you doing something like killing those 9 people, then you have waived your own right to your life. Do you get that? You don't need a government to tell you that. But if you can't figure it out without a government telling you that, please do the rest of us a favor and don't do anything dangerous like voting.

Comment Re:O RLY? (Score 1) 309

Any major manned project at this point is going to involve a lot of robotic probes and preparation.

Yeah, we're already doing that. We've sent robotic probes to the Moon, Mars, and the asteroid belt lately. Have you forgotten about all the hubbub over the bright spots they found on Ceres? We are *not* ignoring the asteroid belt.

But asteroids are a lot easier to get to and from than Mars, precisely because of their lack of gravity and lack of atmosphere.

I disagree. True, Mars has enough of an atmosphere to be a nuisance (because you need reentry shielding, but there's not enough there to be really useful for aerobraking), but it's also significantly closer than the belt. Farther = a longer journey. For a probe, a few extra months might not be that big a deal, but for humans, it is. Mars is already too far as it is (as in, "too long a journey for most people to want to sit in a spacecraft that long", plus the radiation concerns).

A lunar space elevator might be a nice project. But in the end, the moon is a really harsh environment, the resources it has are hard to get at, and it, too, has just too much gravity.

The environment isn't that harsh; it's 3 days away (super-close in celestial terms), and there's no annoying atmosphere, and just enough gravity so that we can operate on it without having to invent all-new methods for every simple little thing. But the gravity is low enough that a lunar space elevator should be quite doable, unlike Earth (where the gravity is way too high so we don't have good materials with enough strength, and we have a thick atmosphere that causes all kinds of problems with such an elevator).

The proximity of moon to earth also means that remotely operated robots are a reasonable alternative to manned exploration.

I disagree entirely. For simple probing around, sure, that'll work OK, but if you want to do any really serious work, you have to have boots on the ground. Remotely-operated vehicles are *not* going to build factories, mines, etc. We do *not* have that kind of technology yet. Some heavy-equipment stuff could definitely be converted to remote-control: dump trucks, shovels, etc. But that'll only work as long as nothing goes wrong. As soon as something breaks or gets stuck, you're going to need some people there to deal with it. So you could definitely get by with a lot less manpower on-site, by operating a lot of vehicles remotely, but you'll still need some. It's just like our UAVs ("drones") used by the US military: the planes are flown remotely, I think even by people stateside, but you still have to have real people on-site in the theater to refuel them, do maintenance work, etc., when they land. It'll be the same for heavy equipment on the Moon.

I still think our primary focus should be exploration of the asteroid belt, first with robotic probes, then towing asteroids into lunar orbits, creating habitats, and finally moving out there.

We're already exploring the asteroid belt. We could stand to do more though. But there's no reason we can't get started building habitats and industrial facilities on the Moon simultaneously. We already know there's a crapload of asteroids out there with valuable ores, so we might as well prepare for using them. And we should definitely be working right away on building the technology for capturing and towing these asteroids.

Comment Re:sunfire / in my stellerator / makes me... happy (Score 1) 97

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) 97

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:Fusion energy is impractical (Score 1) 97

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.

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