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Comment Re:I know its not an original idea (Score 3, Interesting) 29

Second order effects. The following is wrong and grossly oversimplified but gives some idea of how it works.

The 2.7K Cosmic Microwave Background (CMB) is understood to be red-shifted thermal emissions from a 3000K H/He plasma from when the universe was very young. The red shift is caused by the expansion of the universe. Dark matter can cause small variations in either the temperature or polarization of those thermal emissions by gravitationally making the plasma denser (and hotter) or less dense (and cooler). Detailed measurements of the CMB is what has really motivated most of the dark matter / dark energy picture.

Comment Re:Time for lead lined bras and skirts! (Score 1) 90

Nope - it's not the solar wind. The energy of the solar wind maxes out around 20keV. The Al skin of an airplane will completely absorb a charged particle (electron, proton, alpha) at that energy. We are talking about both solar and galactic cosmic rays. But to make sure my failing memory isn't the problem, I went and looked it up. In one of the original papers on this topic "Radiation exposure of aircrews", Occup Med. 2002 Apr-Jun;17(2):293-309 it says:

The principal ionizing radiation is galactic cosmic radiation. On infrequent occasions, radiation from the sun leads to an increase in the ionizing radiation at aircraft flight altitudes.

Or from the far more recent FAA technical report

Sources of ionizing radiation most likely to be encountered during air travel include galactic and solar cosmic radiations, radioactive cargo, radioactive substances released into the atmosphere, lightning, and terrestrial gamma-ray flashes."

The FAA paper also has this chestnut about the solar wind:

At its highest intensity, the solar wind can adversely affect telecommunication systems, but particle energies are too low to increase ionizing radiation levels at aircraft flight altitudes (Friedberg et al., 1992). Any environmental effect from the increased intensity of charged particles from the Sun is called space weather.

And this too:

Lower in the atmosphere, at 20,000 to 40,000 feet where subsonic air-carrier aircraft commonly cruise, neutrons, and electromagnetic shower components are most important.

So like I said in my first comment, a magnetic shield is going to do squat. Nearly all of the dose at aviation altitudes come from neutrons and gammas. Also, the cosmic ray flux is higher at the poles. That's only been understood for about 50 years.

Comment Re:Time for lead lined bras and skirts! (Score 1) 90

Of course - neutral cosmic particles are unaffected by the earth's magetic field. I think you missed my point. The presence of the atmosphere is what make a magnetic shield of limited use.

Most of the dose due to cosmic rays at typical aviation altitudes does not come from direct absorption/scattering of the cosmic ray in the human body or the aircraft. Instead, the majority of it comes from secondary particles created when the cosmic ray interacts with the large atmospheric column above the aircraft. The shower of secondary particles decays to protons, neutrons, gammas, electrons, and muons. Several papers (both modeling and direct measurements on aircraft) indicate that dose to humans is largely from secondary neutrons and gammas.

Comment Re:Time for lead lined bras and skirts! (Score 3, Informative) 90

Magnetic shielding has limited benefit in the atmosphere. Much of the dose at flying altitude is from secondary particles produced by cosmic ray air showers ( from cosmic rays that interacted with the atmosphere above the plane). Some of those secondaries are charged and could be magnetically deflected, but there are plenty of gammas and neutrons too. In space, a magnetic shield is a great idea.

Comment Re:Why so negative? (Score 1) 48

Exactly. On top of that, a typical apt update/upgrade takes less than a minute. For some users, the need for a reboot after a kernel update is a pain but you can do that when convenient.

Any windows update beyond antivirus seem to take at least 30 minutes, uses half the machines resources, and requires a reboot (or two sometimes).

Comment Re:DUV is a dead end (Score 4, Informative) 87

Never been in a fab I see.

For most processes, only the first few layers (out of 50 or more) are printed with the highest resolutions tools. As you move up the device stack, the layers have both larger dimensions and are thicker. Tools like EUV can print very small features but they also have a very small depth of focus. Because of this (and cost and throughput), a fab will have just a few of the highest resolution tools, and a bunch more of the lower resolution tools all the way up to non-DUV (365 nm I-line tools) that only have 300 nm resolution. Fabs will continue to have DUV tools for a long time to come.

I have no idea if this new machine is actually capable of anything, but they are claiming immersion DUV. This is the most advanced DUV technology utilizing a layer of water between the lens and the wafer to increase numerical aperture (and make smaller features). Immersion and EUV are both embargoed from China. The Chinese are able to purchase dry (non-immersion) DUV and UV machines from ASML.

Comment Re:playing devil's advocate (Score 1) 53

None of descriptions describe it this way, but it seems likely that their "wave spring" adjusts the resonance frequency of the system. They talk about getting vertical motion 3x the wave amplitude under normal conditions, so it must be something like that. Because it is on resonance, there are already big differences in the forces (during parts of each cycle) on the anchor under normal wave conditions than you would expect from buoyancy during wave motion.

I don't think they are applying breaking forces during a storm, they are adjusting the system to be off-resonance to the wave to minimize motion. There will be large forces on the anchor during a storm, but that seems like it would be one of the primary design parameters.

The closest mechanical analog (but not a great one) I can think of is paddle ball (a rubber ball attached to a wooden paddle with a rubber band). Off resonance the ball flops around randomly, and on resonance it has a very large amplitude.

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