joak

29 ms·

331.
Fusion Powered Helicity Drive at 2021 Mars Society Convention(youtube.com)
1 points by joak 4y ago|1 comments
332.
by joak 4y ago
Btw: people also invented hammocks (somewhere in South America). Hammocks are really comfortable, why comparing beds with sleeping on the ground? What's the point? Maybe to be able to tell something like "primitive people and gori
333.
by joak 4y ago
Previously discussed here: https://news.ycombinator.com/item?id=30842587
334.
by joak 4y ago
Grading students is probably an archaic way of teaching. You want them engaged not cheating. But ok, institutions want grades... What about this solution?: https://theconversation.com/i-no-longer-grade-my-students-wo...
335.
Zephyr solar-powered drone smashes record with 2-month-long flight(newscientist.com)
12 points by joak 4y ago|2 comments
336.
NASA mission to 16-Psyche, a Metal-Rich Asteroid Maybe Worth $10 quintillion(smithsonianmag.com)
5 points by joak 4y ago|0 comments
337.
by joak 4y ago
And another one here 5 days ago: https://news.ycombinator.com/item?id=32298994 It seems to me that the nuclear lobby is particularly active these days. My impression is that the window for nuclear is rapidly closing. The al
338.
by joak 4y ago
Wind and photovoltaics just skip the heat part in the cycle. Electricity is generated without converting heat to kinetic energy. This is also the case of helion energy fusion solution. Aneutronic fusion with direct energy conversion. No hea
339.
by joak 4y ago
Solar and wind have these economic properties: - the marginal cost of energy is zero (once the investment made producing a kWh is free) - fix costs are almost zero For the nuclear energy we have the following: - the marginal cost of energy
340.
by joak 4y ago
There is this idea that nuclear is not being deployed because people have a wrong perception of risks. However, the main reason is the economy. The costs of solar, wind and batteries are dropping exponentially but the costs of nuclear are n
341.
Lonsdaleite (Hexagonal Diamond)(en.wikipedia.org)
2 points by joak 4y ago|0 comments
342.
by joak 4y ago
Quantum computers are not faster classical computers. They solve some problems exponentially faster than classical computers. For example we can break RSA keys with a quantum computer because we have a quantum algorithm (Shor's algorit
343.
by joak 4y ago
Yep this is why I stopped using firefox for android, they restricted the list of extension they support. I had extensions I didn't want to stop using so I stopped using firefox on android and moved to chromium Too bad
344.
by joak 4y ago
Chrome for Android has no extensions at all. Most webpages are unusable on mobile without extensions like ublock origin or "I don't mind about cookies" (this last one is for removing the annoying warnings about cookies in EU)
345.
by joak 4y ago
I was using firefox for Android but they removed the support for extensions (actually there is a restricted subset of curated extensions that are allowed). So I moved to a chromium based browser. I was using firefox on my laptop because it
346.
by joak 4y ago
Also in Helion machine magnets coils are in aluminum. And because aluminum is (mostly) transparent to neutrons they don't get damaged. This is to be compared with the superconductors of tokamaks. So actually their idea is to put the sh
347.
by joak 4y ago
Exactly, if you build a coal power plant today, the LCOE is calculated assuming the facility will run, let's say, for 30 years at 80% capacity. But what happens if you have to stop your power plant in ten years because its (LCOE-estima
348.
by joak 4y ago
This conversation seems to me a bit outdated: building a fission reactor takes one or two decades and its kWh is costlier than alternatives. To get something cheaper, we need to wait for the next gen of technology, in one or two decades. Lu
349.
by joak 4y ago
And what about non-DT fusion? Helion, funded by Sam Altman, is doing DD/DHe3 fusion. Non-thermal fusion with direct energy conversion. They are attempting net electricity for 2024.
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by joak 4y ago
The total amount of waste heat is low. Thermal pollution is a local problem (rivers getting hot) but not a global issue.
351.
by joak 4y ago
And what about Helion Energy tech? Pulsed collision of plasmoids (FRC), with direct energy conversion. Deuterium helium3 aneutronic fusion, no neutrons. They've received $500M (lead by Sam Altman) to demo net electricity by 2024.
352.
by joak 4y ago
Geothermal, and all thermal power energy, have a big issue: thermal pollution. You need a lot of water for the cooling phase of the thermodynamic cycle that transform heat into electricity. That's why during drought episodes fission pl
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by joak 4y ago
Pretty cool startup. Digging 20km deep holes, and only in 3-4 months, this would be amazing.
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by joak 4y ago
The main issue with geothermal energy is that it needs cooling and that means water, a lot of water. I do not have the exact estimates for geothermal, but in the US the current numbers are 15 gallons to produce 1kWh of electricity. source:
355.
by joak 4y ago
Exactly, the neutron induced radioactivity is orders of magnitude lower than in fission by-products and is a minor issue. The problem is more with neutron embrittlement that weakens the materials exposed to fast neutron radiations. For DT f
356.
by joak 4y ago
As I understand the neutrons of the D+D->He3+n reaction are slow neutrons (2.45MeV) that won't damage too much the materials. These are not the fast neutrons of the DT fusion (14.06MeV) They claim it won't be worse than waste n
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by joak 4y ago
Actually their only primary fuel is deuterium. The fusion reactions are 2/3 of D+D and 1/3 of D+He3 D+D fusion reaction yields 50% of T+p (tritium and a proton) and 50% of He3 + neutron So in total their fusion reaction does not c
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by joak 4y ago
Actually they have raised (a round lead by Sam Altman) $500M to demo net electricity by 2024. Then their plans are to have a factory to build 20 50MW-generators per day. Each generator is shipping-container size. Link to the interview in lo
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Helion plans a manufacturing facility to produce 20 fusion generators a day(heraldnet.com)
5 points by joak 4y ago|4 comments
360.
by joak 4y ago
Strange loop à la Hofstadter

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