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Comment: Re: It's still reacting carbon and oxygen... (Score 1) 142

by dgatwood (#48438297) Attached to: Coal Plants Get New Lease On Life With Natural Gas

- the nuclear plants require a lot of sweet water for cooling, 24/7, and the world is running out

Not really. Only once-through nuclear plants require large amounts of fresh water continuously. Most plants use cooling towers instead. Some plants don't even use water in the recirculating parts of the cooling systems (e.g. molten salt reactors).

Also, once-through reactors, if designed to do so, can use salt water instead of fresh water.

- it's pretty much unflexible regarding any peaks or lows in consumption

Only because they aren't designed to do so. You can significantly reduce the output of a plant very quickly, but you can't speed it up quickly, currently, because of the buildup of Xenon-135 as a fission byproduct, which is a strong neutron absorber, and the only way to get beyond that is to pull the fuel rods out far more than is safe, and once the uranium fission restarts, the Xenon is quickly destroyed, resulting in a rapid increase in neutron levels in the core, which would overheat the reactor before you could bring it under control.

However, there are a couple of designs that don't suffer from that problem—integral fast reactors and molten fuel reactors both allow the xenon to be separated from the fuel. And I think pebble bed reactors could also be readily made to be largely immune to this effect by cycling in different fuel pellets in while the xenon in the recently used pellets slowly decays.

- the latest generation concrete housings' carbon foorprint takes a decade to offset

I think your numbers are way off. According to David MacKay, spread over a 25-year lifespan, it only comes to about 1.4 grams of CO2 per kWh. In other words, it offsets its construction cost compared with coal in just a little over a month, by my math.

Comment: Re:Oh god, no. (Score 1) 158

by dgatwood (#48427743) Attached to: Number of Coders In Congress To Triple (From One To Three)

Almost by definition, some of those scientists and technology exports would be industry scientists and technology experts, though some wouldn’t be. There’s your range of viewpoints. What I’m arguing is that the range of viewpoints on a science and technology committee need not include the anti-vaxxers, people who don’t believe in evolution, and people who truly think that computers work because of magic smoke. It should mostly or entirely consist of people with some science or technology background in the real world, because those folks are going to have the actual experience needed to understand how their decisions will affect things in practice.

Comment: Re:Oh god, no. (Score 2) 158

by dgatwood (#48422865) Attached to: Number of Coders In Congress To Triple (From One To Three)

The thing is coders are underrepresented as we have no reason to be there.

Actually, I would argue that science and technology committees should be populated almost entirely by people who understand science and technology, so to the extent that government is creating policy in those areas, there should be coders among the elected officials.

Comment: Re:IQ of congress (Score 1) 158

by dgatwood (#48422827) Attached to: Number of Coders In Congress To Triple (From One To Three)

Every change means more headaches when the bill goes to reconciliation between the two houses. That’s one of the big disadvantages of a bicameral legislature—there’s a strong disincentive to fixing problems by the time a bill gets out of committee, which means if you’re not on the committee, you usually have little to no say unless the problem with the bill is grave, in which case enough people vote against it (you hope) to keep it from passing, and the committee has to rethink it.

This also points to a serious flaw in the way committees operate. Instead of a committee consisting of everyone with an interest in an issue, with open discussion, the committees are carefully selected groups consisting of a proportional number of members of each party, and are not necessarily the people who are most interested in that particular issue, but rather the people who are ostensibly most interested in the broader topic of the committee (at best). This is pretty much the exact opposite of the way that things should be done, assuming the goal is to actually pass the best, most reasonable bill possible.

So yes, the entire system is pretty much broken from top to bottom, to such a degree that progress is always made in spite of the system, never because of it. And that’s part of the reason so many bills end up being basically prewritten by lobbyists.

Comment: Re:Change is coming, so... (Score 1, Interesting) 498

by dgatwood (#48414735) Attached to: Rooftop Solar Could Reach Price Parity In the US By 2016

Why? That’s just silly. Solar users sell power when prices are high and buy power when prices are low, but their billing is based on kWh, not cost, so the power that those customers get credit for during the day has a much higher value to the power company than the power that they get back at night. The power companies make a huge profit off of those solar users’ surplus power compared with what they would be paying for peaker plants. They can readily afford to absorb the infrastructure cost even if the customer is consistently producing more power than they consume.

If you’re going to go to that scheme, then to be fair, they should have to pay time-of-day rates, where every kWh that the solar panel users provide gives them three or four kWh at night in return. And no power company wants that.

Comment: Re:don't tax alternative energy and transportation (Score 5, Insightful) 498

by dgatwood (#48414707) Attached to: Rooftop Solar Could Reach Price Parity In the US By 2016

But we need to pay for infrastructure. SO we need to tax electricity to recoup lost revenue form the gas tax.

It would make more sense to crank up the diesel tax. Big trucks cause about three orders of magnitude more damage to roads than cars do anyway (one 18 wheeler does as much damage as 9,600 cars, according to the GAO), so it is only fair that trucking companies should pay essentially the entire cost of upkeep. If they raise the taxes high enough, perhaps we’ll see a resurgence in the use of trains for shipping (which is more energy efficient, too).

Comment: Re:Hail resistant? (Score 4, Informative) 498

by dgatwood (#48414677) Attached to: Rooftop Solar Could Reach Price Parity In the US By 2016

Are this things hail resistant? Lower prices are interesting only if won't be smashed by some pieces of ice falling from the sky

Generally speaking, yes. Anything complying with international standards is required to handle a 1 inch chunk of hail at terminal velocity (50 MPH). Many panels are rated up to 4x that, for added robustness, but I doubt those are the cheap ones. :-)

Comment: Re:My two cents... (Score 4, Insightful) 498

by dgatwood (#48414669) Attached to: Rooftop Solar Could Reach Price Parity In the US By 2016

Net metering is when it runs backwards? That's probably find in a single month. But to carry it out over the year doesn't seem fair because during winter months, the solar panel user really is taking advantage of the grid.

How is that not fair? As a solar panel user, you’re no different from any other generator company. If I’m producing power, I darn well expect the power company to pay me for it, just as I expect to pay them if I’m using more power than I produce. What would be unfair would be an arbitrary limit to how far ahead you can build up bill credits towards future bills, because that would mean that I produced power that the power company benefitted from, and sold to somebody else for more than they should have paid me for it, but then didn’t pay me for it. That’s called stealing where I come from.

Besides, on average, solar power users produce power during the day, when demand is high and the cost of production is relatively high (because peaker plants are expensive). They consume power mostly at night, when demand is low and the cost of production is low. So no matter how long a cycle you average it over, the power plants are making a big profit from buying relatively cheap solar power instead of expensive natural gas peaker plant power (while selling that power at the same price). That more than pays for the negligible marginal grid maintenance costs arising out of providing power to one extra home.

And if you produce more power than you consume for a whole year, the power company gets an even bigger windfall profit. In most places, net metering happens on a one-year cycle. They pay you if you use less power than you produce over the course of that one-year period, but at least here in California, they pay a whopping 3 to 4 cents per kWh (less than half the production cost for solar, last I checked). As a result, there’s really zero advantage to overbuilding; the goal is to get as close as possible to breaking even over the year, without going significantly over. And, of course, they resold your extra power at up to 38 cents per kWh....

Comment: Re:(Vorsicht vor den Vögel!) damn birds (Score 1) 150

I was about to make the same crack, but in English. Crank that baby up to solar furnace levels of energy. Then, when the bird tries to perch in front of the laser, it gets rapidly cooked and falls. As a bonus, you could start a KFC franchise right below the tower.

Alternatively (and more seriously), mount several lasers a few feet apart and use channel bonding. If one laser goes dark, turn off its mate in the opposite direction, and try again on a preset schedule. That way, the sending end immediately knows the link is down and can rate-limit the data flow and use fewer links until the problem corrects itself. You'll drop a couple of packets, but the link will hold.

Comment: Re:This isn't new (Score 5, Interesting) 326

by dgatwood (#48399251) Attached to: Apple Disables Trim Support On 3rd Party SSDs In OS X

The real problem here, as I see it, is that the developer of the TRIM enabler is writing bug reports that request a ridiculously complex solution that doesn't make much sense, rather than a very trivial solution that does.

The right way to solve this problem would be for Apple to add a single line of code that checks for a magic value in the device tree, and enables TRIM support if it finds it. Then, the TRIM enabler could write a codeless kext for any devices whose TRIM support seems to work, whose sole purpose is to add that magic value into the device tree, that matches at a higher priority than the Apple driver, modifies the device tree, and walks away from the table, allowing the Apple driver to attach, see the flag, and use TRIM support.

Heck, there's probably a flag like that in there already. Just looking at the device tree for my Apple-branded drive in 10.9, I see something pretty glaring:

"IOStorageFeatures" = {"Unmap"=Yes}

and thirty seconds later, found the documentation for that key here. Chances are, if you write a codeless kext that modifies the device tree to add this property to the device, and if you get your matching correct, the unmodified Apple driver will magically enable TRIM support. If so, then you just need to get a proper signing key from Apple, sign the codeless kext, and you're done. If not, file a bug asking for that approach (or a similar approach with a different key) to work.

If that approach doesn't work, then and only then should you even think about writing an actual chunk of kernel code.

Comment: Re:Anybody familiar with the manufacturing side? (Score 1) 111

by dgatwood (#48393431) Attached to: An Applied Investigation Into Graphics Card Coil Whine

I guess it depends on how bad the noise is. I could believe one in 10K or one in 100K. I'd have a hard time believing that a manufacturer would ship something with enough noise to bother one in 1K people. Usually I'd expect the noise to be in a frequency range where most adults either can't hear it or can barely hear it.

Comment: Re:Anybody familiar with the manufacturing side? (Score 1) 111

by dgatwood (#48393413) Attached to: An Applied Investigation Into Graphics Card Coil Whine

I'm deeply underqualified to tell you how DC-DC converters do work...

Me too, but I'll try anyway. After all, this is Slashdot. :-D

If I understand correctly, a buck (downstep) converter starts with an oscillator that drives a transistor. The transistor turns the power source on and off very rapidly. An inductor between the high source voltage (after the switch) and the low-voltage output effectively turns the resulting current cycling into a voltage drop, and a capacitor smooths the resulting power supply back into DC. A diode bypasses the source and switch, ensuring that current continues to flow when the switch is off.

The duty cycle of the oscillator determines the resulting output voltage, so if you're starting at 12V and need 3V, you would use a 25% duty cycle (an oscillator whose output is on 25% of the time, and off 75% of the time). The frequency of the oscillator must be well above the human hearing range for obvious acoustic reasons.

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