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Comment Re:Boat still hasn't left port (Score 1) 255

Austrian approach does not view economics as science, rather as a deductive study.

Well, yes. It's a religion, or more appropriately a cult. It has a set of pre-determined conclusions and finds excuses for them. E.g.: "Economy is doing great - a good time to cut taxes on the rich and reduce social safety network!", "Economy is sputtering - need to reduce taxes on the rich and kick poor people more, so they work harder!", "Economy is crashing - that's because taxes were not reduced enough, cancel taxes on the rich and force all those lazy poor to work for slave wages!".

So answer this simple question: when is it a good time to raise taxes and improve social safety net?

You probably wanted to say "recessions happen because customers do not have money". Deflations (in the sense of falling price levels) occur in other situations too (for example increases in productivity that outpace the increase in the money supply) and don't necessarily have the effects associated with recession.

No. I was precise in my description. Deflation happens ONLY when consumers have no free money to spend. I've actually studied ALL the documented episodes of deflation in the last 120 years in all of the countries. Out of 60 cases there was only ONE exception (Sweden, 1992) where a nominal deflation coincided with economic recovery, and that's only because deflationary processes had been arrested by a quick and decisive stimulus actions, helped by increased export revenue.

Deflation does not always lead to Depression-scale slowdowns, but it's never associated with good times.

1. There are situations where a falling price level does not cause a recession (say in the consumer electronics sector, or the examples from the Atkeson/Kehoe paper I linked)?

There are no such situations.

Comment Re: Batteries just don't store enough energy... (Score 1) 194

Also, there's a lot of diversity in terms of aircraft electrification that one can take, it's not an all-or-nothing thing. There's lots of different proposals for varying degrees - for example, high bypass with electric turbofans, using onboard electricity to spin the compressor so that you don't have to have a turbine, and so forth.

Comment Re: Batteries just don't store enough energy... (Score 4, Insightful) 194

Yes. Also, you can't ignore comparative efficiencies of engines. Or engine mass to weight ratios. Or the length of time to market, and the expected level of battery change during that time period. Or side benefits (for example, the ability to have small, very light engines was made use of in one NASA experiment that placed numerous small engines along a wing, causing an effect that created drastically more lift at low speeds and allowing for a much shorter takeoff distance).

And beyond that, you can't ignore economics. Having reduced range but getting your fuel at a fraction of a cost may ultimately prove to be more desirable. It's a very complex issue that one can't just make all-encompassing statements based on a single figure like "energy density of batteries vs. energy density of fuel".

Anyway, this is hardly Elon's first time to mention it. Years ago he mentioned that he wants to be the first person to have an electric plane break the sound barrier. If there's anything one can say about Elon, it's that he sure doesn't set the bar low...

Comment Re: This is why we can't have nice things (Score 1) 194

That's why private property is a good idea. If the natives owned the property (the last monarch's corruption makes it worth a separate argument) , they'd probably want the rent. Or at least the builders would have known ahead of time that building the telescope was not worth their time. If the scientists owned the property then it would have just been built already. The idea of "public property" is what leads to these sorts of conflicts; low - IQ politicians are a far worse way to decide issues then rationally-enforced market discipline.

Comment Re:I disagree (Score 1) 131

I'd say so. Coding is design + typing + debugging. This removes the typing (and the need to learn syntax and wrestle with silly syntax errors) and much of the debugging.

If you like coding with most of the tedious annoying bits removed, you might like actual coding. Or at least for "top down" people, it's a good approach.

Comment Re:Icebergs float on glaciers (Score 5, Informative) 36

No, it does not form "one huge crystal". Nitrogen ices at these temperatures have little structural integrity. It was well known before we got to Pluto that if we saw any sort of relevant topography, we'd know immediately that it was from water ice, as nitrogen ices are so weak that they'd just flow slack over time.

Comment Re:Icebergs float on glaciers (Score 5, Informative) 36

Nitrogen ices at these temperatures, while crystalline, have rather low viscosity. If you put weight on them, they slowly diffuse around it until the object either sinks or is buoyantly balanced out. The latter happens in the case of water ice.

Also, it's worth noting that it's not pure nitrogen ices, it's a nitrogen-carbon monoxide-methane eutectic. Nitrogen is the most common component, however. Also, there are multiple crystal phases that can be taken, depending on the conditions. Nitrogen ices are most famous for having some rather "explosive" phase transitions between different states.

Comment Re:Look at past innovations (Score 1) 255

Secure?? How? If your Bitcoin wallet is compromised through buffer overflow in that nice NFC-handling code then your money is GONE. There's no way to rollback BTC transactions. If my credit card gets compromised, I get all my funds back and receive a new card by mail in a couple of days.

If a bitcoin merchant sends you a bobcat, you're screwed. If a credit card merchant sends me a bobcat, I simply issue a chargeback and get all my money back.

Where exactly is security?

Comment Re:Boat still hasn't left port (Score 1) 255

Austrian religion (it's not a "school"), as usual does not make predictions. It doesn't use models so it can't do that.

According to mainstream economy, deflation happens because consumers DO NOT HAVE MONEY to spend. So the producers have to cut prices to sell at least _something_. This in turn leads to wage decreases and layoffs. And this in turn leads to consumers having less money. Rinse, wash, repeat.

Reality is often a little bit messier - wages rarely fall in nominal values, they tend to stick at zero growth. So nominal deflation doesn't appear, instead no-flation (1% inflation) happens. See: "European Union", "Japan".

Comment Re:sunfire / in my stellerator / makes me... happy (Score 1) 98

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:sunfire / in my stellerator / makes me... happy (Score 1) 98

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:sunfire / in my stellerator / makes me... happy (Score 1) 98

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) 98

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.

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