Follow Slashdot blog updates by subscribing to our blog RSS feed


Forgot your password?

Comment Here's the thing... (Score 1) 295

We keep hearing about these interesting 3D-printed firearms, and the limitation is always along the lines of "everything works except the barrel, which blows up after X number of shots." The Shuty in the article uses a Glock barrel and other parts to get around this.

It seems that the obvious thing to do would be to design a firearm kit - a series of parts that you could combine with a standard item or two (a steel tube that you could buy anywhere and convert to a barrel with minimal work, plus a breech). Include a simple rifling jig in the plans, and you have a real firearm, instead of an "almost" gun. It might take a custom cartridge (if you can't find a suitable steel tube off the shelf). Or leave it smoothbore and make a shotgun.

Heck, you could make a modern Gyrojet if you could get the ammo, and the only steel you'd need would be the firing pin...

Comment Re:For a lower price... (Score 1) 407

In other words, "use expensive materials in a complex sandwich, plan on replacing the top layer on a regular basis, and hope it works for long enough to generate enough electricity to pay for itself."

They have NOT "solved the problem of slickness." They mentioned it in passing, and tested some textured surfaces that are better than nothing, but pretty much all of the solar road "solutions" are just handwaving - and expensive handwaving at that. Look at the initial "we could melt the snow off the road" claims (which turned out to be one of those "Laws of Thermodynamics" things that would never work).

Here's the kicker: as good as asphalt and concrete are at being road surfaces, they still break, a little. They're fault-tolerant. Take a good look at any road more than a few days old. It will have a lot of little cracks, divots, and other wear points that the glass roadway will not be able to handle. Glass cracks, you have to replace it. A seam opens up between panels, you need to seal it before water gets in. A foundation problem pops up (AKA a pothole)? Shut the road down for hours, pull the panel, rebuild the foundation, and replace the panel.

Nope. Sorry, it's still a supremely silly idea.

Comment Re:For a lower price... (Score 1) 407

The "extra strength" is just a matter of thicker materials and deeper foundations. We build lots of similar structures all over the world without any problem.

This is much, much, MUCH cheaper than engineering solar panels + glass to take the weight and impact of motor vehicles. Tempered glass, while nice and strong in many situations, isn't that good for roadways. Especially when you consider how slick glass is, even when textured.

The "solar bike path" they built in the Netherlands a couple of years ago cost about a hundred times what a similar "normal" solar installation would have. Even if adding stronger uprights cost twice as much, it's a better deal than driving on the solar cells themselves.

Comment Re:For a lower price... (Score 1) 407

The panels wouldn't have to be any more rugged than standard ones - they're going to be "up on the roof."

Also, your theory of "cars will run off the road and people will crash into the posts" isn't really supported by actual highway use. If you were right, then every tunnel or narrow road would be a horrible deathtrap - and they're not, by a large margin.

At worst, you just put a guard rail along the sides of the road. It would be insanely cheaper than the solar roads themselves.

You don't have to "roof" the highway, anyway - just build a one-sided overhang from the panels. By angling it, you get as much energy from a single eight foot wide panel as you would from a highway-width one. At worst, just build the thing ten feet off the side of the road, still on the right-of-way, and be done with it.

In any case, building a simple frame to hold relatively lightweight solar panels is certainly going to be much, much cheaper than completely re-engineering a modern two-lane highway with transparent materials and super-ruggedized solar panels, to boot. ...and while tempered glass is certainly a strong material in some senses, it becomes much, much weaker when it gets even mildly scratched, or when struck with a heavy object. Like when a car rolls along it with a few pieces of gravel stuck in its tires, or when something falls off a large truck. Asphalt and concrete are much more damage-tolerant in this respect.

Comment For a lower price... (Score 3, Interesting) 407

Build 1000 km of above-the-road arrays.

They wouldn't have to ruggedize the panels to let cars drive on them, they could angle them for better efficiency, and they could repair most of the things that will go wrong without having to shut down the roads.

For that matter, they could BUILD the damned thing without shutting down the roads.

Comment Of course... (Score 4, Insightful) 230

The FAS also claimed that more-precise weapons back in the 1970s, 1980s, and 1990s would cause nuclear war.

And that a missile defense system would cause nuclear war (except for the one the Soviets built and still use, of course).

Oddly enough, over the last half-century, none of the things the FAS said would increase the chances of a nuclear war actually caused a nuclear war. The things that nearly caused WWIII were things they never actually mentioned...

Comment Re:Nope. (Score 1) 412

I'm sorry, but which designs do you think use multiple A-bombs to trigger a fusion weapon?

Every single one ever fielded as a weapon used one (1) fission device to trigger a fusion reaction, which then caused more fission. That's just _how they work_.

Most of the weapons the US fielded over the last half-century were pretty small, in comparison, due to being more efficient and intended for use in air-launched/dropped weapons and ICBM warheads.

Now, maybe you got confused by the MIRV concept - where they used multiple fusion weapons in one missile - but no, that "multiple A-bombs to trigger fusion" thing is just wrong. I only mentioned the Tsar Bomba because it used multiple fission cores to boost the overall yield. It was never a useful device, in general.

Comment Nope. (Score 4, Informative) 412

If true, it's quite frightening. H bombs currently require multiple small A bombs to triggter, and the bomb casing is also typically made out of non-weapons grade uranium which reflects and focuses the A-bomb blasts onto the tritium and deuterium core.

First, no, you don't need "multiple small A bombs to trigger" a fusion detonation. You need one. You can make multi-stage weapons like the Tsar Bomba, nobody seems to nowadays.

Second, you can supposedly make the tamper out of a lot of different materials (even lead) - but even if you decided to use uranium, any country with a big enough program to make an A-bomb would have a crapload of uranium metal sitting around.

Comment Re:State doing the CYA thing (Score 2) 261

You do not understand how classified etc works. It's not about the markings it's about the content.

I beg to differ. Back when I was in the USN, I had a Secret clearance, and if it's been pulled, I've never been notified. (It certainly should have been by now, as I got out in early '73.) I never had access to the type of classified information we're talking about here, but I do know that for most people, if a document isn't marked as Classified, the default assumption is that it isn't.

If you had a Secret clearance back then, it was changed to "inactive" when you left the service. There's almost certainly a piece of paper that you signed when you got out. It's possible to reinstate that clearance within 24 months, but after that time lapses without an active clearance, you have to be re-cleared.

Most people may believe that part about "if it wasn't marked, it's not classified," but it's a false assumption, and when they gave you the initial briefings for that clearance way back when, they certainly told you.

More to the point, a lot of the information in the Clinton emails was initially classified and marked as such - but someone took the markings off when they sent it. For that matter, if you know something classified and merely re-type it into an email, it's still classified. In a position like Secretary of State, a LOT of things are "classified by nature."

Comment Re:...and the power goes where? (Score 2) 386

HVDC interconnectors work great, but not through areas where there are a lot of violent people who like blowing up things that belong to Europeans.

There are a few places they could install underwater HVDC lines, but it would be tough to find someone to fund the multiple billions of dollars in hardware it would take.

Comment ...and the power goes where? (Score 2) 386

To get any good out of that much electrical power, you'd need a huge market to sell it to.

Europe wouldn't be it - too far away, across the Mediterranean. The rest of Africa? Maybe once the political landscape settles down. No bets on that one, though.

Sell electricity to the locals? The poor ones? In a region where oil prices are naturally low?

Build a whole bunch of new industries to use it? You're in a chicken-and-the-egg situation there. Nobody would build the factories until the power was ready, and nobody is going to build the solar system until they know they can sell the power. Then, of course, you need to ship raw materials in, and train a whole generation of factory workers from scratch, in a relatively short period.

And, as others have mentioned, solar plants in deserts have the "sand question" to deal with. Beside the whole issue of sandblasted glass, you have to keep them clean, which means, in general, water. Which is in incredibly short supply in the Sahara.

Of course, the authors admit these issues, but handwave it with "state involvement," which means "we need to get governments to pay for this silly thing."

Comment Re:Surrounded? (Score 5, Insightful) 336

Because solar farms, while really cool-looking from the air, look like miles and miles of supporting hardware from ground level.

The plan is basically "turn a farm community into an island surrounded by several square miles of industrial plants." People move to the country to get away from such things, it's not surprising that they're resisting having their property values trashed because someone decides to take a bunch of government cash to build the darned things.

Slashdot Top Deals

Consider the postage stamp: its usefulness consists in the ability to stick to one thing till it gets there. -- Josh Billings