Slashdot Mirror
FSU Sets 7 World Records In High Magnetics Research
spence calder writes "FSU's High Magnetic Field Lab, more specifically my Kenpo teacher, just broke 7 world records, and brought the record for a superconducting magnet to 25 Tesla. Check it out at FSView and a more detailed article here. Now if only our football team was that cool." And if you'd like your magnetic toys to shoot metal bits,
Jason Rollette points to his
railgun project, which looks like good, clean, high-voltage fun.
Jason's Blog has tons of cool pictures And video. I doubt it holds up.
That'll keep those damn Americans off my base.
FP
Anti-social? My code is just platform-specific.
Yep, Alfred Nobel probably said a similar thing when inventing dynamite.
Now if only our football team was that cool Are you sure you're a geek?
Everything seemed to be going so nice
'till the end of all beings punched right through the ice
is railgun.org
They have a detailed overview of the physics involved, too.
Rational thought is the only true freedom
Neither article got into any detail, but I get the impression this is just a "bigger better" thing, not any particular breakthrough. Just put a few more coils and you get something stronger...no big surprise? Or is there something I'm not seeing here?
Is that no material can take the EM pulse AND the physical abrasion. I guess levitating the object and magnetically containing it during its travel might work but no one has done that so far AFAIK. Every rail gun experiment I have seen needs to replace the rails every couple of shots if they try very high pulse energies.
There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.
Since they are working on a system called "Repeatable Access Denial System" they just have to be mentioned on slashdot!
No one knows the effects of an 25 Tesla magnet on biological tissues. In addition, in order to get useable information out of an MRI system, one must hit it with radiofrequency (RF) waves. The higher the static field is, the higher these frequencies are going to be. A 7-tesla magnet uses frequences around 300 MHz. Therefore, by extrapolation (which I believe is right, since I know that a 9T system uses about 383 MHz), a 25 Hz system would need about 1.1 GHz. This might very well be extremely detrimental to biological tissue. In other words, to do MRI, you'd have to cook your sample.
Finally, to truly achieve a resolution advantage, you will need very powerful gradients. The gradients one would need to take advantage of such a system would be gigantic, at least tens if not hundreds of Tesla per meter. This would be very difficult to design for samples as large as a human body, if not impossible with today's technology, and at the very least extremely expensive.
Personally, I can see a 25 Tesla magnet being useful, just not for MRI. Perhaps for NMR being using not for imaging purposes, but in the study of non-soft condensed matter systems (i.e. not biological or organic, but solid state). It would be useful for examining superconductivity also.
One electron has a charge of 1.6E-19 Coloumbs, so you are talking about the equivalent of 6.7E18 electrons moving at 1m/s. One coulomb is the amount of charge that passes through a point in a wire in one second which is carrying one Amp of current.
The instantaneous force being described would be perpendicular to both the motion of the particle and that of the magnetic field. Make a gun with your right hand, let your index finger point in the direction of the charge, let the field point in the direction of your thumb. Stick out your middle finger so it makes a right angle with both digits, and that is the direction of the force.
BTW, at smaller scales, things work a bit differently- it is much easier to make powerful gradients over a small distance (say a few millimeters, or hundreds of microns) than it is over larger ones (say a human torso, or even a forearm). I wish I could be more specific about this, but my theory background on MRI is still a work in progress- I hope I didn't screw anything up in my post above. Any MRI geeks out there, feel free to correct or add anything I missed.
http://www.fsunews.com/vnews/display.v?TARGET=sho
Thats one hell of a soldering iron.
Speaking at Defcon 12 - Credit Card Networks Revisted: Pen
If you are old enough to read this and comprehend words such as "carpal" you are most likely older than the whole magnetic scam - unless you include the last time this was done by discredited folks such as Mesmer well over a century back (yes - it was a joke then too and only belonged in horror novels).
yes this will also change the fridge magnet industry beyond recognition.
Bush and Blair ate my sig!
So it is kind of a matter of concentration. Your keys aren't going to flying out of your pocket b/c these magnets get turned on, nor will they affect your compass because you are too far away from the space that they affect. The earth on the other hand will affect your compass, because you are in its (fields) area of affect.
Just curiously, if these fields are being generated as 500,000 times stronger than tha earth's own... are they detectable from space?
Now, I may be just stupid, but I'd say the people at the
High Field Magnet Laboratory in Nijmegen have a much stronger claim
to world records... (33T continuous, 60T pulsed).
Where is the world record?
None of my credit cards seem to be working anymore...
It's possible to go to generate higher continuous (i.e. as opposed to pulsed) magnetic fields, using hydrids of superconducting and electromagnets.
I saw a hybrid magnet in the Insitutue of Materials Research (KINKEN) in Tohoku University (Sendai, Japan) with a maximum field of 31 T.
http://www.imr.tohoku.ac.jp
I got the impression that there are other devices (worldwide) with even higher continuous fields.
Why don't they just spike the football and turn this on at one end of the stadium?
To know that you know what you know, and that you do not know what you do not know, that is true wisdom. --Scooby Doo
In that case, the equivalent of Coulomb's Law becomes
F=q(E+v x B)
Here, F is force, q is the charge that is moving, E is the electric field (if present, you may remember something like E=kq/|r|, which is basically the force law you listed divided by a charge, giving units of Newtons/Coulomb), v is the velocity of the moving particle. All quantities in bold refer to vectors, so they not only have magnitude, but direction. In the case of the weber definition above, there is no electric field, so that part has no contribution. We are then left with:
F=q(v x B)
Here, the x does not just mean normal scalar multiplication but vector multiplication. All this means is to take into account the angles between the directions of the velocity and the magnetic field. Either way, the force will be perpendicular to both, so if you can imagine drawing lines indicating the velocity and magnetic field lying in a plane, the force the particle experiences points straight out of that plane. The more in line the velocity and field are (i.e. the smaller the angle they make relative to one another in that plane) than the smaller the force will be. If the particle is moving in the direction that the magnetic field points in, then it will experience no force- again, this is a result of the vector multiplication (better known as the cross product, where A x B=|A||B|Cos[theta], where theta is the angle between A and B.
Make sense? If you have questions, post them here.
By holding a piece of paper over it and sprinkling some iron filings?
"You lied to me! There is a Swansea!"
Perhaps, after the recent power outages in the US, the most important application of supercoducting magnets could be power storage. There seem to be 2 ways they are used - either to make friction-free magnetic bearings for traditional flywheel systems, or (more interesting) direct short-term storage of power. For situations where you need to temporarily store a *lot* of power this is an interesting technology alternative to batteries/hydro/etc.. Current devices seem to cover mainly very short term variations, but what about covering longer term regulation (hours/days) of variable power from a wind-farm, or solar, for example?
Anyone got more gen on this?
Try Superconducting Magnetic Energy Storage (SMES) Systems
This link describes a commercial device that stores 3 megawatt-seconds..
"You lied to me! There is a Swansea!"
Perhaps if you were only in the business of scanning plastic containers for contraband...and sort of ferromagnetic material that you would "scan" using a magnet in the multi-tesla reigon would be subject to becoming deadly projectiles.
This is a record field for the superconducting magnet, not for the whole system. FSU magnet lab does hold the record for hightest DC (constant) magnetic field 50T. This is achieved by putting a resistive magnet inside a superconducting magnet. Resistive magnet burns a lot of energy (10MW), but one cannot use superconducting alone; once the current (magnetic field is proportional to it) reaches a certain value, the superconducting material becomes normal. The record up to now has been something like 14T for superconducting magnet (outsert), the new outsert will allow the DC fields in that lab to go up to 60T.
Ya gotta love a town where you can buy draft beer by the gallon practically anywhere. BY the way FSU is one of the few universities with a full-time bail bondsman on staff.
Gay Goaters!!
To ensure perfect aim, shoot first and call whatever you hit the target
"FSU's High Magnetic Field Lab, more specifically my Kenpo teacher, just broke 7 world records, and brought the record for a superconducting magnet to 25 Tesla. Check it out at FSView and a more detailed article here. Now if only our football team was that cool."
What makes you think people here know something about 'football'?
You expect the arcing to be the familiar blue-violet glow, but instead, you see bright yellow arcing because of the residual helium, and some reds and greens from the vaporizing metals in the ceramic superconducting wire.
The heat of the electrical arc spreads the failure to the surrounding superconducting wire. It starts slowly, but the electrical fire seems to be spreading at an exponential rate. Through the thick pyrex view plate once so clear but now covered in places with an opaque layer of condensed metal smoke, and in others so foggy that all you can see is flashing yellow electrical arcs tinted in places with other colors, you see the immenent destruction of the whole lab. The heat will build pressure in the coil chamber the helium and vaporized metal plasma will weaken the three inch thick pyrex view plate, causing it to shatter. You run for it.
Outside you watch the side of the building for smoke, nothing, no sign of the disaster within. People rush out of the exits and gather next to the person - you - who was considerate enough to pull the fire alarm.
BANG!! The brick wall bursts, smoke, broken bricks, and glass, and a brief yellow flash. The glowing gas bubbles upward, ball shaped for an instant before disappearing.
You watch the smoke billow out of the building. The roof has not collapsed. You creep around a wide circle to see into the building you just destroyed. There is a loud buzz. You see a mean blue-violet-green stationary arc from the end of your 12 inch thick melting copper cable to the ground cable. Red hot copper has eaten it's way through the floor, and started a fire in the basement. Hopefully it doesn't fall on the huge tanks of fuel oil they use for heating.
BANG! They blow up. The fire pressurized the kerosene-like fuel in the tanks, causing them to explode. The normally benign hydrocarbon is atomized, hot volitile and well mixed with air. The entire building shatters spraying splintered, burning wood, and crumbled brick bits of wall for hundereds of feet in every direction. The billowing orange, no red, no black mushroom cloud rises into the sky, a beacon for the fire department to find. All eyes are on you. It was your lab that blew up. You melt backwards towards the parking lot and take off squealing your tires on the way to the newstand to look for another job..
Eat at Joe's.
But their plot to take over the world will ultimately be foiled by Jean Luc Picard.... errr..., wrong show, but you get the idea.
And another thing - where's the radiant electricity that they promised to beam from towers in 1900? Transmission lines and power cords - blech.
As someone who works next door to the FSU Mag Lab, and has taken a tour of the facilities, I have heard a couple things about it that boggle the mind... First, if they didn't contain the magnetic field that they are producing, they claim that it would erase everyone's floppies, hard drives, and credit cards in the entire city of Tallahassee. Second, they consume one quarter of the entire power consumption of Tallahassee to create the fields they are creating. The city of Tallahassee had to install a power generation station nearby just to get power to them easily. They apparently ramp up the magnets while everyone else is sleeping, in order to prevent brownouts during the day.
Out of curiosity, I just looked up their electric bill online, but it lumps the Mag Lab's usage with multiple other FSU buildings... The total bill was $500k this month, so it must be an amount less than that.
Slashdot's first reaction to VMware
Hrrmmm.... =/
First of all, you would have the slight problem of buildinga magnet with a bore large enough to fit a car through... Because the magnetic field strength is proportional to the inverse of the square of the distance, that would have to be a freakin powerfull magnet to fit a truck through.
Assuming that you could build a magnet that large, one would then have a slight problem that any and all ferrous-metallic parts in the car or truck would be attracted to the magnet. Essentially, the magnet would probably pick the car up, off the ground; the car would fly towards the magnet at a very fast velocity; there would be a very large crash; and the car and magnet would become one big mess of magnetic metal.
unfortunately, the only feasible method of implementing this idea would be to have all-plastic cars. also, one would need to implement laws and legislation to prevent anybody with a pacemaker, aneurism clips, or heart pump from driving a car...
anyhow, to make a MRI car scanner, one would probably need to design a low-field magnet (so the cars don't get pulled towards it), and extremely sensitive radio transmitters / receivers. The trick to building an MRI car scanner would be in designing the radio transmit/recieve coils (which could possibly be built in a tunnel kind of way). If I were to try building this type of scanner (and I happen to work with a 1.5 Tesla MRI cryomagnet every day) I'd try putting a 0.5 tesla magnet *under* the road.
However, one would need damn good lawyers in the case that somebody with a pacemaker was riding in the car being scanned, and the car scanner turned off their pacemaker. The litigation would be a nightmare, I'm sure.... Also, one has to worry about FDA licensing, highway & transportation authorities, etc. etc.
At FSU, Seminole Football pays the bills. This is the Magnet that Bobby Bowden built. Even if none of the revenue paid for this research directly, it paid for a lot of other programs that would have been competing for those dollars at budget time.
For those that would die defending it, Freedom
has a sweet taste that the protected will never know.
The wire used for helium-cooled supercon magnets (Nb-Sn or Nb-Bi alloys) has performance envelope that limits the conditions under which it will superconduct. The factors describing this envelope are
- the temperature
- the current
- the magnetic field
Getting to 20T was accomplished by- better alloys -- mainly higher Nb content iirc
- lower temperature -- achieved by cryopumping the liquid helium (LHe)
- more turns in the winding, allows higher magnetic field without increasing the current
Unfortunately, the critical field (the field at which the material goes non-superconducting) is around 20T. Since the innermost coils are sitting in a field near the field at the bore (these are toroidally wound magnets), you need to use a different material. In this case, that material is HTSC wire. This poses some big engineering problems, including making a sufficient length of the wire (measured in km), and making superconducting joints between the HTSC coil and the LTSC coils. It appears that this team has solved these problems, congrats to them.Your explanation of the cross product is sligtly wrong. I think you mean
| A x B | = |A| |B| sin[theta]
i.e. you forgot the magnitde on the left hand side and it's sin instead of cos