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Comment Re:Vacuum (Score 1) 143

... the logical conclusion to lighter-than-air flight: vacuum airships

Vacuum, of course, has less mass than either H2 or He. But mass is the wrong way to look at it. You should be looking at "bouyancy". H2 is half the weight of helium, so twice as good, right? Wrong. H2 is 7% the mass of air, so it gives a buoyancy of 93%. Helium gives a buoyancy of 86%. So that is only a 7% difference in lifting capacity. Vacuum gives a buoyancy of 100%, but that is only 7% better than H2. All the problems that come with maintaining the vacuum, and dealing with the pressure difference, is not going to be worth it for just a 7% gain. This is the reason that vacuum airships have never been built, and likely never will.

Comment Re:Helium (Score 2) 143

Interesting. Is that because hydrogen is diatomic, and thus always bigger than monoatomic helium even though the atoms themselves are smaller?

Basically, yes. H2 has a bigger radius than monoatomic helium. But H2 can be absorbed into metal, embrittling the metal in the process. The electrons will disassociate, and the protons can then drift through the metal and diffuse out the other side. So if the container is metal, the H2 will leak out faster, otherwise the helium will.

Disclaimer: I am a programmer, not a chemist. So if you are building a blimp or hydrogen storage facility, you might want to double check all of this.

Comment Re:Helium (Score 2) 143

The only reason these are necessary is that the residents live in sparsly populated areas.

They are deployed first where electricity is $1/kwh, but if they can be scaled up and mass produced, we could use them everywhere. If you go up high enough, you can almost always find strong winds. Unlike many other renewables, these could be used for steady baseload power. There is a lot of potential for this technology.

Comment Re:Helium (Score 2) 143

Hydrogen leaks easily

But less easily than helium through non-metallic materials. Even a party balloon will hold hydrogen for days. This thing will have less permeable material, and a much higher volume/surface ratio, so it should be able to stay up for weeks before needing a hydrogen top up. It might even be able to make its own H2 by collecting condensation and doing electrolysis.

every electrical contact in the generation systems is a potential ignition point.

It is suspended in a gale force wind. It is extremely unlikely that the hydrogen slowly diffusing through the covering will build up enough to ignite.

Comment Re:Customers may benefit... maybe (Score 1) 455

umm, 2 points do not a blip make... There is not enough data there to support either of you.

Read the study. There were a lot more than 2 data points. Wal-Mart was cheaper, month after month. Then, for one month, due to some sales, Target was cheaper. So the headline is about the "myth" of lower prices at Wal-Mart. The author of the article also blames Wal-Mart for killing Bangladeshi seamstresses, so she may be a little biased.

Comment Re:Customers may benefit... maybe (Score 4, Insightful) 455

IF the government would raise the minimum wage to a 'living' level then we'd see a slow move away from food stamps.

Unlikely. Raising the minimum wage would result in more automation, more outsourcing, and higher unemployment. Most people on food stamps have at least one household adult that is unemployed or underemployed. Young black men have an unemployment rate of 40%. The problem is not "low wages" but "lack of entry level jobs". It is unrealistic to expect an unskilled and poorly educated young man with no work history to compete for a $15/hour job. He isn't going to get it. Instead, he needs an $8/hour job to gain some experience, and learn some basic job skills, like showing up on time and dressing appropriately. Then he can move up. But that won't happen in you remove the bottom rung from the ladder.

Comment Re:Customers may benefit... maybe (Score 4, Interesting) 455

If you drill down to the actual study, what they found was that Target was cheaper than Wal-Mart by 0.46% for ONE MONTH. The preceding months, Wal-Mart had been cheaper by over 2%. So this was apparently a blip caused by some one-off sales at Target.

Comment Re:Helium (Score 4, Interesting) 143

While Hydrogen is significantly more dangerous ...

These are unmanned. So even if a tiny fraction burn up (due to lightning or whatever), I don't see how that would be much of a problem. Hydrogen burns very quickly, so would be consumed before it hit the ground. Just make sure they are tethered so they don't fall on a populated area.

Comment Re:Customers may benefit... maybe (Score 1, Interesting) 455

And because Wal-Mart's a horrible corporate "citizen", *we* get to make up the wage difference for their employees in the form of food stamps & other government assistance.

If they raised wages, we would have to pay more on food stamps, because they would hire different people, and their current employees would likely be unemployed. Have you ever been to Wal-Mart? My local store employs a woman in a wheelchair, and two people that appear to have Down's Syndrome. Most of their other employees don't look much brighter. These people get paid $10 per hour because that is what they are worth. If Wal-Mart is forced to raise wages, then they will pull more capable people from other more useful employment, and their current employees would get pink slips.

Comment Re:Customers may benefit... maybe (Score 4, Interesting) 455

Wal-Mart competes primarily on the illusion of price through loss leaders on a minority of items. The majority of their stock is actually the same or more expensive than many of their competitors.

Citation? There is a Safeway, Lucky's, and Wal-Mart equidistant from my house. I went to all three and priced out a typical cart of groceries, and Wal-Mart was significantly cheaper on EVERY SINGLE ITEM. Overall, I save about 20% by shopping there.

Comment Re:Space travel (Score 3, Insightful) 357

Depends upon your definition of "qualified"

There would be millions of volunteers. If you need a thousand, you could pick the top 0.1%. I would definitely want to go. If you look at history, there has never been a problem getting people to volunteer for dangerous, one-way missions. In the 1500's, there was no shortage of colonists heading out of Europe. The Polynesians colonized every speck of land in he Pacific. The Japanese Kamikaze attacks stopped because they ran out of planes, not pilots. In the aftermath of the Challenger explosion, of the dozens of astronaut candidates, ONE dropped out.

You have a very dim view of humanity if you think there would be a problem staffing a starship.

Comment Re:Well SURE! (Score 4, Insightful) 49

These changes seem reasonable to me. They are getting a warrant with judicial oversight. That is the way the system is supposed to work. If they have probable cause, then there is no reason that I can see for the warrant to specifically tie the search to a geographical location, or to require separate warrants for each machine. Car analogy: Should a search warrant for a vehicle specify that it can only be searched at the suspect's home, but not at his place of work? Should separate warrants be required for the glove compartment and trunk?

Comment Re:Space travel (Score 1) 357

To understand and maintain such technology you need educated people.

Or advanced robotics and a few terabytes of storage for the knowledge base.

Second, to have a stable population you need genetic diversity which also includes larger groups of people.

Or a bank of frozen ova and sperm. Or DNA sequences stored on a flash drive. Humans have 98% of their DNA in common, so you would only need to store the 2% of diffs. If properly compressed, all the genetic diversity of the entire human population of the earth would probably fit in a few terabytes.

Leaving you only with one problem: A large group of people to be willing to leave earth.

There are plenty of qualified people that would leap at the chance to go.

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