Posts by G.R.L. Cowan, H2-to-B convert 22 publicly visible posts • joined 13 Feb 2008
Use the first source to fill a large array (65536 entries is good). Then use the second source to generate a 16-bit index into the array. The entry so found, you export, then replace with the first source's next output.
This is known as algorithm 'M'. It is mentioned in Cryptographic Shuffling of Random and Pseudorandom Sequences, a 2007 paper by Markus Dichtl.
"They will almost certainly receive fatal doses of radiation as they work around the clock."
The Japanese must still be using the 1960s-era KTN2060 "Annihilator" clocks, built of massive cobalt, and frequently passed through the core.
Why won't they learn? WHY WON'T THEY LEARN? Oh, the huMANity ...
"If 1KG takes it 240 miles, why not give it a 3KG tank? iI's not like it's a massive amount of weight...."
Actually it's exactly like that. One of GM's efforts along this line had a tank complex that massed 75 kg empty, 77 kg full.
(<em><a href="http://www.eagle.ca/~gcowan/">How fire can be domesticated</a></em>)
Scarce and expensive uranium? Who do they think they're kidding? It costs barely a dollar per BOE, a penny a BOE to find. If it were scarce and expensive, oil and gas money would not be threatened and antinuclearism would be its own reward.
"... the hydrogen isotopes which would be used for fusion are commonplace and could readily be extracted from seawater ..." as if uranium couldn't. Fukyu. Or more precisely, http://jolisfukyu.tokai-sc.jaea.go.jp/fukyu/mirai-en/2006/4_5.html
It may be possible for a nuclear aircraft to crash without harming the environment any more than the impact of any 2,000-tonne or heavier aircraft, without fuel, would do.
2,000-tonne? Maybe it could be as light as 1,500 tonnes if it's three or four reactors, with three or four no-fooling radiation shields, and hardly anything else. These shields would be like solid 12-foot balls of iron, except about twice heavier, because they'd be made of tungsten, with a cramped reactor compartment in the middle. They would bury themselves deeply in anything they were dropped on. That's not necessarily helpful, nor a hindrance, to their preventing radiation leakage; it's just the way it is.
Some high-temperature coolant, maybe lead or maybe heavy B2O3, would penetrate the thick heavy metal walls and come out again and have its heat transferred to air. The post-shutdown heat could be taken up in boiling the coolant that was inside at the time of a crash. It could work.
--- G.R.L. Cowan, H2 energy fan 'til ~1996
http://www.eagle.ca/~gcowan
Years ago air-breathing hydrogen fuel cells' efficiency, chemical-to-DC, was below 40 percent, even with a power-to-mass ratio such that a car would need 400 kg of fuel cell.
No-one ever puts a hydrogen ICE in one, and a hydrogen FCEV powertrain in in the other, of two otherwise identical cars, with identical hydrogen tanks, and sees whether, if the FCEV sets the pace, the burner ever drops back with fuel starvation. I suspect the FCEV thing runs out first.
So hydrogen cars are not intrinsically EVs. Nor would dedicated nuclear plants use electrolysis; they would use the S-I process, q.v.
--- G.R.L. Cowan, H2 energy fan 'til ~1996
http://www.eagle.ca/~gcowan/
Typical biofuel yields in strongly sunlit regions are 0.25 W/m^2, around 0.1 percent of sunlight in the tropics.
Fantastic algae are fantastic because they could conceivably yield 500 MILLIwatts per m^2 -- not 500 watts. That would be more energy out than sunlight in.
One must anticipate processing losses in the high 90s percent, and a true yield on the order, as with the oil crops, of 0.1 percent. Have you signed the cheque yet? Excellent. We anticipate attaining the promised 0.05 percent very soon. Barring unforeseen difficulties, we'll get you the 0.03 percent you've been counting on by the third quarter next year.
--- G.R.L. Cowan, H2 energy fan 'til ~1996
http://www.eagle.ca/~gcowan/boron_blast.html
Not that big of a deal compared to its total income, but still enough to totally wag the dog in as far as putative efforts to solve the motor fuel problem are concerned. To get government help, the proposed methods must be clearly inadequate. Thus, biofuel. A guaranteed non-solution.
The bit about uranium from seawater taking more energy to extract than it yields is wrong by several orders of magnitude; it probably originates in the non-peer-reviewed "Lying Dutchman" thing. Japanese experiments suggest costs are a few dollars per barrel-oil-equivalent (BOE). On the basis that for every 40 dollars spent on anything, three dollars are spent on fossil fuel, we can derive a <=$0.50 fuel cost for this 1-BOE fuel extraction, i.e. a net energy fraction not less than 0.996.
The reason the extraction is only experimental is that uranium continues to be found on land at a rate exceeding 100 million BOE per day, for a finding cost near $0.02 per BOE, and the market won't bear any price higher than $2.34 per BOE; and that's for long-term contracts. The spot market price has dropped to $1.48 per BOE, which by the 3/40 rule implies uranium extraction for non-long-term contracts now occurs only when its net energy fraction exceeds 0.999.
--- G.R.L. Cowan, H2 energy fan 'til ~1996
http://www.eagle.ca/~gcowan/boron_blast.html
and think they can be sufficiently far from the sources of their wealth. Realization that they cannot changes them; they realize they would rather have a nuclear plant over their back fence than a gas pipeline or a coal rail line, even if it does mean five-billion-plus-special-taxes in natural gas is replaced by 0.2 billion in uranium.
What Frank is missing about plutonium, aside from the fact that it can be removed from nuclear waste and burned, is that its radioactivity is of a kind with which all life is familiar. The top centimetre of the Earth's dry parts contains ten million tonnes of uranium, which like plutonium decays by emitting alpha particles; in the process of transforming to something more stable than itself, it emits eight of them where plutonium emits one.
Since it emits them over a much longer period, ten million tonnes of it are as alpha-active as only 400 tonnes of plutonium. If we someday choose to bury thousands of tonnes of the latter a kilometre or two down, we will then be in a position quite prudently to forget that it's down there, just as we are sensible not to worry that the saltshakers in the Titanic, if they lose containment, will render the oceans undrinkable.
--- G.R.L. Cowan
http://www.eagle.ca/~gcowan/boron_blast.html --
let the baby light matches in the fuel storage room!
Long-chain hydrocarbons might conceivably have a sooting problem, but not, I think, propane. Chilled propane is the best stuff ever; it can be as dense as gasoline but is 18 mass percent hydrogen!
--- G.R.L. Cowan
http://www.eagle.ca/~gcowan/boron_blast.html --
let the baby play with matches in the fuel storage room!
http://www.eagle.ca/~gcowan/boron_blast.html#Liquid_CO2
Large pressure tanks of CO2(l) are definitely hazardous. A tanker truck of this sort killed a lot of people sometime in the past year.
Best is not to have the CO2 at all, and not have any hydrogen either. Almost as good, just let the CO2 go; abundant minerals can and do pull it spontaneously out of air. They don't mind doing the work of unmixing.
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