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Comment: Thermodynamically Impossible (Score 4, Interesting) 311

by Cassini2 (#47135321) Attached to: Solar Roadways Project Beats $1M Goal, Should Enter Production

Isn't it impossible for solar cells to melt significant snow?

The black road surface will effectively capture almost all of the sun's energy. In the northern U.S. and Canada, roads routinely get covered in snow.

The solar cell can capture a portion of the sun's incoming energy, and potentially use it to power heaters to melt the snow. This approach has several problems. Firstly, the solar cells / heater mechanism is less energy efficient than a black road surface. Secondly, if the snow falls when it is dark, the solar cell will stop working (unless it has some big batteries are present, and even they won't last long in a heavy snow fall.) Lastly, the best sun occurs in the summer, and the snow hits in the winter, when less solar energy is available.

About the only way a solar cell can keep up with incoming snow is if the solar array is much larger than the area of snow being melted. However, even then, you still have the problem of the solar array getting covered in snow ...

Comment: Re:No need for UPS to help (Score 1) 207

by Cassini2 (#47132737) Attached to: UPS Denies Helping the NSA 'Interdict' Packages

They also have custom's warehouses for out-going goods. On the U.S.-Canada border, there are warehouses for goods going in both directions. US bound goods get Canadian warehouses, and Canadian bound goods get Canadian warehouses. Both are easily accessed by persons with the right American security credentials. Treaties, special agreements, and informal arrangements are all up-and-working.

Times have changed. Canada is closely aligned with U.S. security policy. During the Vietnam war, draft-dodgers claimed refugee status in Canada. Starting with the new conflicts, fleeing soldiers are sent back as deserters.

Comment: Re:No need for UPS to help (Score 3, Interesting) 207

by Cassini2 (#47128351) Attached to: UPS Denies Helping the NSA 'Interdict' Packages

Many (all?) custom's warehouses are operated by third-party companies. This will be a little bit more complicated than inspecting luggage. However, the companies (subsidiaries) that operate those warehouses get their entire revenue from allowing people to transport goods across borders. I suspect the NSA can get away with almost anything in that environment.

Comment: Risk Statistics (Score 3) 333

by Cassini2 (#46938393) Attached to: NASA, France Skeptical of SpaceX Reusable Rocket Project

In the case of NASA, people were on-board for every shuttle launch, and each launch cost billions. The satellite payload could cost over $400 million each. If a $15,000 dollar component has a 1 in 10,000 chance of scuttling a launch, it was easy to justify fixing it. The space shuttle had many subsystems, and each and every subsystem was built from from many small individual components. Thus, NASA rebuilt, checked or replaced everything on the entire shuttle on every launch.

I don't think SpaceX is going after the same market. For human rated launches, ISS resupply missions, or expensive satellites, they can sell brand new rockets. For inexpensive payloads, it could pay to roll the dice. SpaceX rockets are designed to be much less expensive than the competitions.

Comment: Re:Efficiency? (Score 1) 234

The issue is weight. In a car, weight is an issue. A mechanical gear box is a very light method of adapting engine output for use at the wheels. Electricity cannot match the power/weight capabilities of a mechanical gear box.

On the other hand, a locomotive is a very different application. A train has a huge mass, and the electric generator/motor approach does not add significantly to the total weight of the train. Also, huge advantages exist in the electric generator/motor approach on a locomotive. The diesel engine can be operated at optimal fuel economy. It is possible to apply the maximum torque to the locomotive drive wheels while avoiding wheel slip. When accelerating very large masses, following the optimal acceleration curve is a big advantage. Also, a safety issue exists in trains where wheel failure (and hence derailment) can occur if excessive wheel-slip occurs. Hence a constant traction drive on a locomotive has benefits.

Comment: Re:Does the math work out? (Score 4, Insightful) 193

by Cassini2 (#46799459) Attached to: Why Tesla Really Needs a Gigafactory

GM and the other car makers do not make money on cars. These stats predate the collapse, but GM wasn't make any money manufacturing cars. GM was making money on financing. As such, GM didn't go broke until the banking crisis hit. Similarly, the auto dealers don't make money selling cars. They make money in add-ons and services (including repairs.) For instance, many dealers charge $200 dollars to transfer your ownership, over and above the charges at the DMV. These extra charges add up. I'm pretty sure the repair parts operation at a modern OEM makes far more than the original cars.

Comment: Re:Mathematics is a language, not a science (Score 1) 612

As I recall, many aspects of modern physics fit into the "mathematically inconsistent" category. The equations - as written - are not consistent with one another. Additionally, the equations don't agree with our understanding of reality, and know one knows why. As a result, many mathematician's look at the stuff that happens in physics and engineering as somewhat dubious. Physicists also recognize this problem, and for them, an important theoretical challenge is to generate mathamatical frameworks that both describe reality and are internally consistent (which is hard).

One of my mentors, a statistician, pointed out that if the mathematics yield useful predictions about the problem you are working on - then run with it. Almost all modern sceince and engineering is based on the "it yields effective predictions, therefore we use it" principle. I still find it odd that a statistician was the realist in the group ...

Comment: Re:Normal situation (Score 1) 103

by Cassini2 (#46557951) Attached to: French, Chinese Satellite Images May Show Malaysian Jet Debris

Yes. Lot's of stuff is floating around the ocean. It seems particularly unlikely that large pieces of aircraft fuselage are floating in the ocean, over two weeks after the plane went down, and after heavy storms. The satellite is probably finding wales, bits of long cap-sized ships, sea weed, parts of shipping containers lost at sea, etc. This is the third or fourth time in this search that the satellites have found objects at sea that have not come from MH370.

If they find smaller debris, like the parts of seats and life-preservers, then it is much more likely that they have found the aircraft crash site.

Another issue is that satellite bandwidth is expensive. I don't think the satellite providers bother to download surface scans of the Indian Ocean on a continuous basis. Thus, even if a satellite was in position to capture the crash, it is unlikely that it bothered to down-link the data.

Comment: Re:Hmmm... (Score 4, Informative) 983

by Cassini2 (#46463387) Attached to: How Do You Backup 20TB of Data?

At 10 characters per second, the backup would take 63,419 years(*) and require 659 TJ or 0.2 TWh of power to complete. I have a customer that still uses paper tape. It lasts and lasts, and I have only replaced the reader once. The punch needs a new power supply every 20 years or so.

However, 63,419 years is a long time to wait for a backup to complete.

(*) this assumes that 1 TB = 1,000,000,000,000 bytes. It takes almost 70,000 years if you add the extra 10%.

Comment: Re:Is Win 8.1 that bad? (Score 1) 392

by Cassini2 (#46375219) Attached to: Free (Gratis) Version of Windows Could Be a Reality Soon

The strange thing is: most users adapt to the programs they use, and the program becomes less annoying over time. Windows 8 appears to defy that rule. I hate Windows 8. I've been using it for 6 months now. I hated it at the beginning, and I hate it even more now. I simply cannot make Windows 8 do whatever it is I am trying to do.

A big problem is that Windows 8 does not work well with touch pads. Every other laptop, I use the touch pad. My Windows 8 laptop has a mouse at work, and a mouse at home.

Think of your family tonight. Try to crawl home after the computer crashes.

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