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Comment Re:Ignorance? (Score 1) 236

Yes, the food problem isn't entirely overpopulation-related. However, that's not the only problem mentioned on the page. You explained ONE in terms of it is caused by things outside of overpopulation, but what about all those other problems on the page? If you can't offer alternative explanations for all of them, then overpopulation is real.

Comment Re:Ignorance? (Score 4, Interesting) 236

There are two major types of ignorance, which we can call "passive" and "active".
Passive ignorance is the same as simply not-knowing something. Like, we are ignorant of whether or not there are any living organisms on Mars.
Active ignorance is the deliberate ignoring of facts. See the Flat Earth Society for an example of active ignorance, although there are plenty other offenders, like Creationists who claim the Earth is only a few thousand years old (so explain this), abortion opponents who claim the Earth isn't overpopulated (so explain this), etc.

Submission + - Persons, Exobiology, Dolphin Beings, and Humans->

VernonNemitz writes: On the assumption that many scientists are also nerds who read Slashdot, and knowing that scientists need precise and reliable definitions of words and phrases for accurate communications, I've written a blog article (you mean you haven't yet written one that has an alien-sex scene in it?) that identifies a couple of things that need to be fixed, and which is worthy of getting associated with the FireHose (a sexual thing associated with David Brin's solar-plasma aliens, right?), and might even be worthy of reaching the "front page" of Slashdot. You decide!
Link to Original Source

Comment Re:Efficiency (Score 1) 904

Steam cars lost out to gasoline engines because of the water problem --they couldn't build radiators good enough to condense all the water that had been turned to steam (after the steam had expanded in the engine). So they had to frequently fill a water tank, in addition to filling a fuel tank. Today, we might be able to build efficient-enough radiators, especially if we go the route of making only 20 HP steam engines in conjunction with something that allows rapid acceleration and storage of regenerative-braking energy, as described in prior posts. You make a 150 HP steam engine for a car even today, and you, too, will probably have to add water at regular intervals. And then there is the efficiency problem, in that car-sized steam engines are probably only/roughly 40% efficient (the steam engines in large power plants manage 50% efficiency partly because of size-scaling). Better things are available, for cars.

Comment Re:Efficiency (Score 2) 904

Flywheels can be charged up lots faster than batteries. But actually, my personal preference is for supercapacitors, with almost perfect charge/discharge efficiency, rapid charging rates, AND they never wear out. But so far as I know, nobody offers supercapacitors potent enough to be used in cars, even if only for acceleration-power and regenerative-braking energy storage (while a fuel cell is still superior to batteries for long range). That's why I never mentioned them in any of my prior posts here. Does anyone know if the supercapacitor total-capacity situation is likely to change soon?

Comment Re:Efficiency (Score 2) 904

Both the heavy battery pack and the motor-generator-plus-flywheel (I never called it magical or weightless, but this data suggests it can weigh a lot less than a battery pack) need at least one electric motor to drive the car wheels (did you know one electric motor can drive a pair of wheels without a mechanical differential?). If the battery charges/discharges at 90% efficiency, while the flywheel does it at 95% efficiency, guess which is superior? (And "rare earth" metals are not actually all that rare; the problem has been chemically separating them from each other, to get the particular ones we actually want to use, and the pollution associated with the process. Obviously that technology needs to be improved.)
Another poster has claimed that modern lithium batteries can have better-than-95% efficiency, making them better than a motor-generator-flywheel. If accurate, the only advantage a flywheel would have is a very fast charging time.

Comment Re:Efficiency (Score 1) 904

One other advantage of a flywheel over a battery is that it can be "charged" very rapidly. If you could get it charged near your workplace, a 50-mile range flywheel car could work for you. But I only brought up the subject because flywheels with motor-generators were so much more energy-efficient than any batteries I knew about, and wanted to work toward using them only for rapid acceleration and regenerative-braking storage.

Comment Re: Efficiency (Score 1) 904

That 95-99% efficiency is really good, and if accurate I would be glad to replace the suggested flywheel with a higher-energy-efficient battery, for quick acceleration. I would still want a fuel cell though, for long range, and less total weight (because of not carrying lots of oxidizer around inside the batteries).
Regarding "well to wheel" efficiency, thanks for the extra data to consider. Note that when ordinary coal-fired power plants generate the electricity for electric cars, we still have energy invested in digging and transporting coal. Charging batteries (or making fuel-cell fuel) from renewable resources is the best long-term way to go.

Comment Re:Efficiency (Score 1) 904

Color me slightly embarrassed. After posting the first of the two very-similar messages, it disappeared, and I thought maybe I hadn't actually posted it, but I most certainly had done a full-page-refresh. I didn't notice that the page had more than 250 comments, and that comment was one of the later ones, and therefore not part of the default display. So I ended up writing the message all over again...

Comment Re:Efficiency (Score 1) 904

Apparently the other guy didn't read all of what I wrote. I DID end up talking about using a flywheel in conjunction with a fuel cell. The fuel cell would provide steady low-level power (20 HP or less); the flywheel would accommodate rapid acceleration (and store energy from regenerative braking). There is no need for the flywheel to be so big/dangerous as one which is built to provide for significant-distance driving. And the main reason for using a flywheel instead of a battery is that 95% energy-conversion efficiency of motor-generators.

Comment Re:Efficiency (Score 2) 904

Yes, the danger of a broken flywheel has always been a concern. The recommended solution was to put it inside a shell that can "take it" --which is much easier to do if the flywheel is made of carbon fiber instead of steel. Also, the shell can be somewhat evacuated, to reduce air-resistance losses.

It is impossible to travel faster than light, and certainly not desirable, as one's hat keeps blowing off. -- Woody Allen