Please create an account to participate in the Slashdot moderation system


Forgot your password?
DEAL: For $25 - Add A Second Phone Number To Your Smartphone for life! Use promo code SLASHDOT25. Also, Slashdot's Facebook page has a chat bot now. Message it for stories and more. Check out the new SourceForge HTML5 Internet speed test! ×

Comment With MagLev, Tunnels not needed (Score 1) 220

Fifty years ago, Drs. Gordon T. Danby and James R. Powell of Brookhaven National Labs on Long Island, New York, invented first-generation Superconducting Magnetic Levitation (SC MagLev) Rail, using dipole magnets. This was used for the current JR Central MagLev system in Japan. Since then, they have developed their far-superior second-generation system, using quadrupole magnets. In this system, the vehicles are not so much levitated above the rail, but suspended by the sides of the rail, so that any effort to move the vehicle up, down, or to the left or right, elicits strong restoring forces, meaning it can resist all but the strongest winds. Also, since the gap between the rail and the vehicle is about 4" (10 cm), if the rail gets iced up,it is only necessary to de-ice it to a depth of about 2½" (6 cm). Thus, second-generation MagLev is almost impervious to weather. Also, this MagLev system can handle the steep grades needed when crossing a mountain. With external propulsion power, as much energy as is needed can be used to raise each vehicle over the mountain, and most all that energy would be recovered as it descends the mountain on the other side. Thus, you could have ordinary MagLev vehicles, some as small as individual passenger cars, that could cross over the mountains on open-air MagLev monorails. For details, see, with links to Danby and Powell's work in Group A (Antecedents and Allies). Tunnels are expensive and of limited capacity. MagLev rails are a lot cheaper, and just as good.

Comment Alta Vista and Bayesian "Logic" (Score 1) 172

My experience with Alta Vista was that sometimes it seemed to go "off-track", answering, not my question, but a similar question. When I tried to refine my query, it still seemed stuck on what it thought I asked before, not what I was asking.

I later found out that they used "Bayesian Logic", where the answers to the previous questions guided the answer to the new question. No wonder I had this problem!

When Google came along, of course I went with them, and still do. They are still the #1 Search Engine, although some of their other services, like Google Maps, have become untrustworthy.

Comment I would invest in perfecting MagLev (Score 1) 842

If I had a billion dollars, I would invest in perfecting Danby-Powell superconducting MagLev. See For three-quarters of that amount, a test facility could be built in Nevada (see http://www.readinessresource.n...). This would eventually lead to a nationwide MagLev net that could bring MagLev depots to within ten miles of any point in any built-up (urban or suburban) area.

In ten years, this can replace existing passenger and freight rail, and displace a lot of air travel. In forty years, this could be a multi-trillion dollar industry satisfying most of the county's transportation needs cleanly and efficiently.

Comment Momentum of tachyon traveling at infinite speed (Score 1) 142

One of the strange things about a tachyon is that it can be traveling in one direction for some real inertial reference frame, and be traveling in another direction for some other inertial reference frame. For yet another reference frame intermediate between those two, the tachyon is traveling at infinite speed, yet has zero dynamic mass and a finite momentum of +/- i mc, where i is the square root of -1, m is the imaginary rest mass of the tachyon, and c is the speed of light.

The direction of the momentum vector is ambiguous.

Since this is a total contradiction, I assume that tachyons cannot exist.

Comment I use NoScript; I also have a weak connection (Score 1) 230

I use NoScript, and only allow Javascripts that I trust.
I am also a Comcast customer. The cable connection is through an old, weak cable that goes through the apartment downstairs, and it slows down my connection a bit, but that is tolerable. To fix it, they would have to rip apart the walls in a bedroom occupied by an eight-year-old girl, and I don't want to put any child through that trauma. If I allow Comcast to share my cable connection, then I might be slowed down to an unacceptable level.
Also, their new cable modems DO NOT come with a battery backup -- they make you buy the battery from them.
They say that nobody can take advantage of you without your permission. Well, I'm paying enough in cable bills, and I'm not going to let them. Unfortunately, FiOS is not available in my apartment complex, so Comcast has a monopoly.

Slashdot Top Deals

On the Internet, nobody knows you're a dog. -- Cartoon caption