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Comment: Re:Mythbusters and CRT monitors (Score 2) 87

by jamesc (#41180573) Attached to: IDT and Intel Join Forces For Wireless Charging
I cited Mythbusters for convenience. Plus, they actually try stuff and aren't afraid to admit that they got it wrong and retry in later episodes. That is a lot more scientific than certain groups I could name.

When they get a "Confirmed" result, that's real data. The proposed effect happened under those conditions. When they make a number of attempts, fail, and label a myth "Busted", is when they're the least scientific. Later episodes may prove them wrong. Kind of ironic for a show named Mythbusters.

Anyway, back to the topic. Yes, your 21" CRT does indeed produce large magnetic fields when it is first turned on. There's a degaussing coil wrapped around the front of the tube, inside the enclosure. It's there to erase any stray magnetic fields on the shadow mask. It only runs for a short time.

Thereafter, magnetic fields mess up the picture, as anyone who has held a bar magnet up to a color TV or monitor can confirm.

If we could manage all those years sitting in front of huge degaussing coils, I suspect that our mag-stripe cards are pretty safe. Just exercise a little care.

Comment: Re:mag field "leakage" problems anyone?? (Score 5, Informative) 87

by jamesc (#41180099) Attached to: IDT and Intel Join Forces For Wireless Charging

you have to figure that there should be a considerable magnetic field around these devices so how will this work with say Flash drives credit cards and other "stuff" that does not like being in a above background mag field??

The article stresses efficiency, so presumably it just sends out a periodic magnetic "ping" and doesn't turn on full power charging until a compatable device answers and completes a handshake. Note the 2-Way Secure Communication and Foreign Objection blocks in the block diagram.

Flash drives aren't based on magnetic media, so they don't care about mag fields until they're strong enough to be a concern for you as well. (See Diathermy.) Shouldn't be a problem at the power levels they're talking about.

Credit cards are magnetic, but are fairly resistant to being demagnetized. See the Mythbusters episode "Barrel of Bricks, Third Rail, Eelskin Wallet Demagnetize" on their Collection 1, disc 1, episode 3. It took a fairly strong and changing field to erase credit cards. I suppose I'd keep all my cards several inches away from the charging coil, just to be safe.

Floppies could be demagnitized, but they're curiosities now.

Bare disk drives maybe could be affected, since their cases are now mostly plastic. Not a problem for most people.

I'm not seeing much of a downside otherwise. As is often the case in such matters, convenience in charging stuff will likely outweigh the hassle of an occasional erased mag-stripe card.

Comment: Really cold fusion (Score 1) 114

by jamesc (#36731418) Attached to: Ask Slashdot: An Open Handheld Terminal For Retail Stores?

"Many recent experiments by other scientists in the field have shown that cold fusion can be controlled and predicted quite effectively"

If you have any links to such I would be very interested in seeing them.

As would I, so long as the are links to reproducible experiments, not just irreproducible anecdotes and oddities.

However, don't forget the real cold fusion: muon-catalyzed fusion. http://en.wikipedia.org/wiki/Muon-catalyzed_fusion It works best when truly cold -- like the temperature of liquid hydrogen. ;-)

Too bad that the energy cost to make the muons is much greater than that from the fusion....

Role Playing (Games)

+ - Unusual physics engine game ported to Linux->

Submitted by
christian.einfeldt
christian.einfeldt writes "Halloween has come early for Linux-loving gamers in the form of the scary Penumbra game trilogy, which has just recently been ported natively to GNU-Linux by the manufacturer, Frictional Games. The Penumbra games, named Overture, Black Plague, and Requiem, respectively, are first person survival horror and physics puzzle games which challenge the player to survive in a mine in Greenland which has been taken over by a monstrous infection/demon/cthulhu-esque thing. The graphics, sounds, and plot are all admirable in a scary sort of way. The protagonist is an ordinary human with no particular powers at all, who fumbles around in the dark mine fighting zombified dogs or fleeing from infected humans. But the game is remarkable for its physics engine — rather than just bump and acquire, the player must use the mouse to physically turn knobs and open doors; and the player can grab and throw pretty much anything in the environment. The physics engine drives objects to fly and fall exactly as one would expect. The porting of a game with such a deft physics engine natively to Linux might be one of the most noteworthy events for GNU-Linux gamers since the 'World of Goo' Linux port."
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