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Comment orly? (Score 2) 242

Is that actually true, though? I thought law enforcement, at least, identified fingerprints via a series of distinctive "features" rather than a full image of the fingerprint. In theory, couldn't these features be listed as to their presence/absence and coordinates relative to the center of the fingerprint, creating a consistent hashable value?

Comment Re:Both Sides Are Terrible (Score 2) 618

Let's talk tactical ethics. I don't follow this battle closely, but if I ignore the underlying issues and accept the facts as you present them, the MRAs' lack of concern about collateral damage means that both sides are *not* equally terrible.

Whatever the ethics of attacking your debate opponent's career, attacking their coworkers' careers is definitely not okay. Whichever side is doing it.

Comment Re:Use chemical energy, not thermal energy for sto (Score 1) 139

Even if salt doesn't have high efficiency, it's salt! Just use more. Salt is cheap and widely available...On the other hand batteries degrade over time, they are more complex, and have a lifetime (except for the most exotic designs) measured in a small number of years. Also batteries can short out or catch fire.

I chose a battery type for comparison that's made of dirt-cheap materials, which is highly reliable and very simple. (Far simpler than molten salt plumbing. Just imagine designing valves and pumps to carry a liquid that freezes unless the pipes are glowing red-hot.) You're right that batteries can short out and catch fire, but molten salt is basically on fire all the time, so I'm not sure it's a win.

Ultimately the engineers at this site chose a molten salt design. I think I'll trust their judgment over yours.

These guys aren't general electrical engineers picking the best of all options, it's a solar-thermal company filled with solar-thermal engineers who cut their teeth doing solar-thermal experimental projects, and are out to prove that solar-thermal can work. And sure, they might be right, but the fact that every solar thermal plant up until now has been unable to compete against other renewables and fossils doesn't give me hope.

Comment Use chemical energy, not thermal energy for storag (Score 1, Informative) 139

Molten salt is terrible for electricity storage.

Thermal energy capacity: 0.13 kWh/kg
Electrical conversion efficiency: 25% at best
Electrical storage capacity: 0.03 kWh/kg
Amount of mass to store 12 kWH (one household overnight): 400 kg
Amount of mass to power a large city overnight (1 million households): 1 Empire State Building

Sodium-sulfur battery electrical storage capacity: 0.5 kWh/kg
Charge/discharge efficiency: 80%
Useful storage capacity: 0.4 kWh/kg
Amount of mass to store 12 kWh (one household overnight): 30 kg
Amount of mass to power a large city overnight (1 million households): 1 large submarine

Both systems use cheap, common materials, both systems are proven reliable over decades, but you get about 10 times as much energy storage when you use chemistry.

Comment You can't rank these things. (Score 1) 330

This is about as useful as arguing about the most important person of the 20th century. The refrigerator was huge. So was the mass-produced automobile, the atomic bomb, the television, the transistor, digital communications, the list goes on. And all of these things enabled and depended on each other, so singling out one as the key to everything is stupid.

I do agree that refrigeration deserves more attention, though.

Comment Re:Power from hydrogen (Score 2) 230

Hydrogen is stupid.

The hydrogen engine *has* to be smaller and *has* to use less fuel, because if it carried enough fuel to match the power and range of a gasoline engine, the fuel tank would be as big as the car. (And that's not an exaggeration. OK not much. I did the math.)

Hydrogen has great energy per mass, but its energy per *volume* is terrible -- about equal to lithium batteries. Rather than dealing with synthesizing, transporting, storing, and burning an explosive super-pressurized gas, it's much easier to just use electricity.

Magnesium hydride doesn't help: since it stores only about 8% by weight of hydrogen gas, its energy per mass and per volume are both worse than compressed H2 gas. It might be safer, but it's not gonna solve the fuel tank problem.

Comment Re:Diesel electric would be better (Score 1) 230

What's the difference? I classify the "diesel electric" system used on trains, in which the engine turns a generator but delivers no direct power to the wheels, as just another sort of hybrid. An inferior sort, since directly powering the wheels can be more efficient at some points on the speed/power curve, so it's better to have that option.

Comment Diesel hybrids would be perfect for VW (Score 5, Interesting) 230

I did an obsessive amount of research on VW's clean diesel technology, and the engineering issues that motivated their decision to cheat. Going hybrid would solve all their problems. Well, the technical ones anyway.

The problem is that their patented "clean NOx trap" pollution control technology involves storing NOx pollution in a zeolite "molecular sponge". The sponge needs to be cleaned out periodically by changing the engine fuel-to-air ratio: when that happens (for a few seconds every minute or two), engine performance is drastically reduced. VW's engine computer tries to keep this from happening while the driver is accelerating, but apparently it wasn't good enough, so they programmed the computer to not bother with trap cleaning unless it's being tested in an EPA lab.

With a full hybrid system, the engine can run at optimum efficiency at all times, and can take a break to clean the NOx trap whenever it wants: the electric motor and batteries can take over.

"Survey says..." -- Richard Dawson, weenie, on "Family Feud"