Exotic material boosts electromagnetism safely

Feb 29, 2012
This is an illustration of one of cells that make up the metamaterial structure. The yellow lines are copper. Credit: Wenchen Chen and Willie Padilla, Boston College.

Using exotic man-made materials, scientists from Duke University and Boston College believe they can greatly enhance the forces of electromagnetism (EM), one of the four fundamental forces of nature, without harming living beings or damaging electrical equipment.

This theoretical finding could have broad implications for such applications as magnetic levitation trains, which ride inches above the tracks without touching and are propelled by electro-magnets.

As the term indicates, EM is made up of two types of fields – electric and magnetic. Alternating current sources generate both electric and magnetic fields, and increasing one of them generally leads to the increase in the other. But electrical fields can cause problems if they get too high.

"For any EM applications dealing with things on the human scale, high-intensity EM fields needed for the generation of strong forces interfere with other devices and may be harmful to biological tissues, including humans," said Yaroslav Urzhumov, an assistant research professor in electrical and computer engineering at Duke's Pratt School of Engineering.

"The severity of this problem is substantially reduced if the fields are predominantly magnetic, since virtually all biological substances and the majority of conventional materials are transparent to magnetic fields," Urzhumov said. "While we can't suppress the electric field completely, a magnetically-active metamaterial could theoretically reduce the amount of current needed to generate a high enough , thus reducing parasitic electric fields in the environment and making high-power EM systems safer."

The results of Urzhumov's analysis were published online in the journal Physical Review B, and the team's research was supported by the Air Force Office of Scientific Research.

The solution to this problem comes from the recent ability to fabricate exotic composite materials known as metamaterials, which are not so much a single substance, but an entire man-made structure that can be engineered to exhibit properties not readily found in nature. These metamaterials can be fabricated into a limitless array of sizes, shapes and properties depending on their intended use.

In the magnetic levitation train example, conventional electromagnets could be supplemented by a metamaterial, which would have been designed to produce significantly higher intensities of magnetic fields using the same amount of electricity.

The Duke scientists came up with the theoretical underpinning for the metamaterial, which is being fabricated by collaborators at Boston College, led by Willie Padilla, associate professor of physics.

"The metamaterial should be able to increase the magnetic force without increasing the electric current in the source coil," Urzhumov said. "The phenomenon of magnetostatic surface resonance could allow systems to increase the mass of objects being levitated by one order of magnitude while using the same amount of electricity."

EM is currently being used in a host of devices and applications, ranging from subatomic "optical tweezers" scientists use to manipulate microscopic particles with laser beams, to potentially highly destructive weapons.

Urzhumov works in the laboratory of Duke's David R. Smith, William Bevan Professor of electrical and computer engineering and director of Duke's Center for Metamaterials and Integrated Plasmonics. Smith has previously demonstrated that similarly designed metamaterials could act as a "cloak" to different frequencies of light and other waves.

Wenchen Chen and Chris Bingham from Boston College's physics department were also members of the research team.

Explore further: Interfaces within materials can be patterned as a means of controlling the properties of composites

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Lurker2358
2.7 / 5 (6) Feb 29, 2012
The phenomenon of magnetostatic surface resonance could allow magnetic levitation systems to increase the mass of objects being levitated by one order of magnitude while using the same amount of electricity."


That's incredible.

That Navy Rail Gun? more power, less waste heat and electricity. Incredible. Redesign time if this works...

Trains, planes automobiles.

Why not have magnetically levitated aircraft which are already airborne, eliminating landing gear and friction, etc, at takeoff?

EM is currently being used in a host of devices and applications, ranging from subatomic "optical tweezers" scientists use to manipulate microscopic particles with laser beams, to potentially highly destructive weapons.


Yeah, the Rail gun, or a directed, hot/cold multi-layer plasma shield or plasma weapon contained in a magnetic field is the goal.
antialias_physorg
3.2 / 5 (6) Feb 29, 2012
since virtually all biological substances and the majority of conventional materials are transparent to magnetic fields

Hemoglobin? While it is true that almost all bilogical tissues are unaffected by magnetic fields that's a rather significant one that shouldn't be dismissed.

(Not dissing this research: The ability to boost magnetic field components while keeping electric field components in check is bound to have a plethora of uses)
sstritt
Feb 29, 2012
This comment has been removed by a moderator.
Lurker2358
3.7 / 5 (6) Feb 29, 2012
Wouldn't this be useful in M-RAM and storage media? I mean, if you can lift ten times as much for the same energy, wouldn't that imply being just as strong for ten times less energy?

Implies drastically reduced waste heat and cross-talk in any magnetic system.

Further, could some sort of reversed application be used to make more efficient electric motors? As well as generators for water and wind turbines?
lomed
5 / 5 (3) Feb 29, 2012
Hemoglobin? While it is true that almost all bilogical tissues are unaffected by magnetic fields that's a rather significant one that shouldn't be dismissed.
While the magnetic susceptibility of hemoglobin is considerably higher than water, its susceptibility per unity mass is lower. (ref: http://en.wikiped...tibility and http://adsabs.har.......180S ) It should also be noted that both hemoglobin and water are diamagnetic, so they align opposite to external magnetic fields, partially cancelling them.
SolidStateUniverse
not rated yet Feb 29, 2012
Isn't that just a flat inductor?

That would make it a sort of lense for magnetic field lines, then. Interesting.
Lurker2358
1.4 / 5 (7) Feb 29, 2012
Does anyone else find this article too good to be true?

I thought our electro-magnets were already nearly 100% efficient, since our electric motors are 80% to 85% efficient.

You can't get time times the lifting power out of something that is already supposedly 80% efficient, unless the previous metrics were wrong, or unless some new, freaky physics is involved.

What am I missing?

It's possible our existing electric motors or electro-magnets use a misleading metric of efficiency?

Then again, I have a disk of permanent magnets levitating above a reverse pole disk i.e. N on N, with a central axis holding it in place. It hasn't lost any noticeable life since I made it.

This implies that Gravity never depletes the magnetic field, such that the electricity actually does no "work" during times when the field is unchanging.

Maybe "nearly 100% efficient" electromagnetic machines are possible?
Lurker2358
1 / 5 (2) Feb 29, 2012
Isn't that just a flat inductor?

That would make it a sort of lense for magnetic field lines, then. Interesting.


That's what I was thinking a moment ago, but it seems so ridiculous and counter-intuitive that I feared to write it.

I don't understand how this obeys conservation laws for linear and angular momentum, unless it's somehow focusing an entire hemisphere of the magnetic field into a beam in each direction, with equal canceling taking place, but even that would require exotic physics and a re-write of text books...

It's borderline over-unity, unless this article is using poor wording.
Lurker2358
1.5 / 5 (4) Feb 29, 2012
On my post two posts ago, about the permanent magnet always negating gravity, with no depletion.

Shouldn't an electromagnet be able to "fake" this using some sort of spintronic or quantum entanglement effect?

Why not permanently magnetize the rail, and then it takes no electricity to lift the train at all? It always just hovers. Then you could use something ridiculous like a fan on the back for propulsion, much like an "air boat" or a hovercraft??

Why not?
SolidStateUniverse
4 / 5 (1) Feb 29, 2012
If you were to laminate the poles of the magnets with this sort of magnetic lensing system, it seems you can control the angle of the field lines exiting the system. Like a sort of magnetic field line laser. If the field requires a certain volume of space to for the magnets to cancel angular momentum and levitate a train against gravity, if you were to narrow the available width of the field for cancelling the seperation between the magnets must increase.

Well, thats how I'd see it.

I also see this being used in fusion reactors.
indio007
1 / 5 (1) Feb 29, 2012
Further reading.

Magnetic levitation of metamaterial bodies enhanced with magnetostatic surface resonances.
Yaroslav Urzhumov, Wenchen Chen, Chris Bingham, Willie Padilla, David R. Smith
http://arxiv.org/abs/1111.1695

The great thing about this is it doesn't take crazy technology to implement.
You could do it in your basement using stuff from the junk yard.
fmfbrestel
not rated yet Feb 29, 2012
Does seem particularly fantastic, but it did come from Duke and Boston College not some fly by night research team. potential uses seem to be everywhere.

Lurker: the magnet that is levitating is depleting, just very very slowly. That magnet will deplete at about the same rate as your table would if you sat the magnet on your table.
nkalanaga
not rated yet Feb 29, 2012
Lurker2358: Permanent magnetic maglev trains have been demonstrated as small scale models. The problem is that magnets large enough to levitate a full-scale train are much more expensive than electromagnets, and require scarce rare-earth elements. If cheaper permanent magnets were available it's likely no one would try to use the electromagnets.

The Germans before WW II built a conventional train powered by a propeller. It worked fine, but the air blast blew the ballast off the track, breaking windows along the line. There are ways around that, and a maglev could very well use a propeller.
SolidStateUniverse
not rated yet Feb 29, 2012
Ahhh.... I got it. It's like a magnetic yagi.
Demitroy
not rated yet Feb 29, 2012
I'm still in school, and still learning a lot of the basics that others probably take for granted, but does this have any implication in the search for room temperature super conductors? I guess I'm just wondering if being able to increase the magnetic field means it is possible that a lesser/warmer conductor could be used to the same effect as a supercooled conductor?
bewertow
not rated yet Feb 29, 2012
I'm still in school, and still learning a lot of the basics that others probably take for granted, but does this have any implication in the search for room temperature super conductors? I guess I'm just wondering if being able to increase the magnetic field means it is possible that a lesser/warmer conductor could be used to the same effect as a supercooled conductor?


Nope. As far as I can tell, this would have no impact on high Tc superconductors. Superconductivity is a quantum mechanical effect.
antialias_physorg
5 / 5 (1) Mar 01, 2012
I guess I'm just wondering if being able to increase the magnetic field means it is possible that a lesser/warmer conductor could be used to the same effect as a supercooled conductor?

Large magnetic fields inhibit superconduction. The exclusion of magnetic fields, though, might help. But even then Tc is still the main factor - and that is measured at a magnetic field of zero.
So unless someone finds a way to create 'negative magnetic fields' that's not going to help.
http://hyperphysi...cbc.html

The Germans before WW II built a conventional train powered by a propeller.

I had the model of that. But the real problem was the danger to bystanders and that it couldn't go up steep slopes.
http://en.wikiped...zeppelin
kaasinees
1 / 5 (2) Mar 01, 2012
What about electric cars? Someone should inform the lightning GT developers.
roboferret
not rated yet Mar 01, 2012


Why not permanently magnetize the rail, and then it takes no electricity to lift the train at all? It always just hovers. Then you could use something ridiculous like a fan on the back for propulsion, much like an "air boat" or a hovercraft??

Why not?


If you're magnetically levitating anyway, you may as well use linear induction motor. Simple and efficient, it doesn't need any moving parts. What does interest me is the concept of the vacuum maglev - running in an evacuated tunnel, they would be essentially frictionless, and could be accelerated to huge speeds with very little power. The power could even be recovered while using the linear inductor as an electromagnetic brake. It would be a colossal engineering task, but it would revolutionise transport and commerce. London - NY in an hour, not a problem, the speed is limited to the space and time you have to accelerate.
ab3a
not rated yet Mar 01, 2012
Thanks to indeo007's link, I see they're actually discussing a negative permeability material. The article failed to mention those words, so the rest of it made very little sense.

Paired with conventional permeability materials, one ought to be able to focus a magnetic field very tightly. Another thought is that this might help with getting Tokamak fusion reactors to work better.
antialias_physorg
5 / 5 (2) Mar 01, 2012
Why not permanently magnetize the rail, and then it takes no electricity to lift the train at all?

Because permanent magnets are far to weak for that. You need an electromagnet to get the field strengths necessary to lift a multi tonne object (at lest if you want it to have the surface area of a conventional train).

the concept of the vacuum maglev - running in an evacuated tunnel, they would be essentially frictionless, and could be accelerated to huge speeds with very little power.

While the friction would be reduced the power requirements to keep a long tunnel at near vacuum would be enormous. Also the train would need life support and, in the event of a hull breach, would be a fast-moving death trap. Then there's the problems of stations (how do you board such a vehicle?). Add to that the huge costs (because these only make sense on long range trips). Digging through 10km of rock takes a year at current rates - and that's not even sub oceanic but just accros the alps
Lurker2358
1 / 5 (2) Mar 01, 2012
Then there's the problems of stations (how do you board such a vehicle?).


Air lock. The train slows to a halt. An airlock room is evacuated of air and opens. the train enters the airlock which is re-pressurized. Passengers get on/off and the train is sealed again. The airlock is depressurized and opened onto the track again. This way, you don't need to depressurize the entire track every time.

Then again, engineering a tunnel to be air tight and survive -14.5 PSI while holding up the mass of the soil and water above it would require space station tolerances.

If you were going to make a trans-oceanic railroad, it's probably cheaper to use floating platforms with tethers to the sea floor, and run the rails on top of those.

Of course, you'd need to design it to allow shipping and large waves to pass through the spaces.

Floating bridges have been done before, as far back as the Greeks and Persians, even in war time.

need industrial scale mass production of carbon metamaterials
antialias_physorg
5 / 5 (3) Mar 01, 2012
Floating bridges have been done before, as far back as the Greeks and Persians, even in war time.

We're not talking rivers. We're talking oceans. You know: those little lakes with tsunamis, hurricanes, sea quakes, freak waves, ... and you want to build a pontoon bridge over that? Are you out of your friggin mind?

need industrial scale mass production of carbon metamaterials

Argh. Please. Stop. I'm sick of every idiot here just grabbing a technical term out of thin air and thinking that it applies everywhere.
If you want to sound smart then for the love of god at least google the tech term before you use it. Star-trek babble just makes you sound stupid.
This has nothing to do with metamaterials, whatsoever.
infinite_energy
1 / 5 (2) Mar 01, 2012
What does interest me is the concept of the vacuum maglev - running in an evacuated tunnel, they would be essentially frictionless, and could be accelerated to huge speeds with very little power.


This can easily be tested on the experimental Maglev track in Germany. They can/should build a polycarbonate tunnel on top of their ring track and vaccum it. Now the maglev speed could be supersonic.

antialias_physorg
not rated yet Mar 01, 2012
This can easily be tested on the experimental Maglev track in Germany

'easily'?

Do you even KNOW what the test track looks like?

Reality check: Project the cost of 'polycarbon' tunnel that can withstand a vacuum and either enclose the entire structure over the entire length or be free floating off the ground starting at the top level of the stilts.

I think you and I have a very different definition of what 'easily' means (probably also of what 'expensive' means).
infinite_energy
1 / 5 (2) Mar 01, 2012
This can easily be tested on the experimental Maglev track in Germany

'easily'?

Do you even KNOW what the test track looks like?

Reality check: Project the cost of 'polycarbon' tunnel that can withstand a vacuum and either enclose the entire structure over the entire length or be free floating off the ground starting at the top level of the stilts.

I think you and I have a very different definition of what 'easily' means (probably also of what 'expensive' means).


Not doing anything can not be more expensive either.
Air friction is the main waste of energy for high speed trains. You want to go faster you need to eliminate the air friction thus remove the air around the train.
Plus the train will be isolated from weather elements.

"One atmosphere (101 kPa or 14.7 psi) is the amount of pressure that can lift water approximately 10.3 m (34 ft). Thus, a diver 10.3 m underwater experiences a pressure of about 2 atmospheres (1 atm of air plus 1 atm of water)."
infinite_energy
1 / 5 (2) Mar 01, 2012
So the polycarbonate tunnel should be strong enough to resist ~15 m underwater pressure: easily doable if not with polycarbonate than with steel.
The tubes could also be build with concrete and semiburied in the ground.
antialias_physorg
3.7 / 5 (3) Mar 01, 2012
The question is: How many trillion would it cost to have something like this dug beneath the ocean (only to be destroyed in the first earthquake anywhere along the route)
As an example I give you the Eurotunnel (between France and the UK. 50km long, 40m deep beneath the English Channel. Total cost 12.5 billion Euros).
Despite exorbitant prices per ticket (higher than Paris-London by plane) and good capacity utilization it will never recuperate the cost of building it (it makes about 40 million a year surplus).

Now extrapolate 12.5 billion for 50km to almost 2850km (shortest distance accross the Atlantic Liberia-Brasil). And that at enormous depths. With specs (airtight, maglev, rescue points, HUGE power stations along the way...) that are MUCH more demanding than the Eurotunnel.

Even if we could miraculously get a 100fold cost savings: No way this makes sense.
jalmy
1 / 5 (2) Mar 01, 2012
So basically you put in the same amount of electricity and get out a bigger magnetic field. Very interesting. So it would also be true that to maintain a certain field it would take less electricity. So you you could make more efficient electric motors. I agree with some of the above posters, that could be very good news for auto makers where 1% is a huge deal when your trying to run a car on batteries. But what they don't mention is how hard this material is to manufacture, and how expensive it is.
roboferret
not rated yet Mar 02, 2012
The question is: How many trillion would it cost to have something like this dug beneath the ocean (only to be destroyed in the first earthquake anywhere along the route)

The proposals I've seen (no, it's no my crazy idea, Robert Goddard proposed a similar idea 100 years ago) have the system operate in buoyant tubes attached to the ocean floor. This removes a huge amount of cost, and problems such as earthquakes and continental drift are mitigated. Maintaining a vacuum isn't such a huge issue either. We're talking about a sealed tube, not a spacecraft with windows and hatches. We already have ocean floor pipelines for transporting oil and gas - maintaining a vacuum isn't a big deal when you're already sealed against high pressure water. I'm not saying it wouldn't be expensive, but it is technically possible, with current technology. In fact, the Chinese are developing one at the moment. (google vactrain)
Lurker2358
1 / 5 (2) Mar 03, 2012
I don't know man.

Maintaining a buoyant sub-surface track would seem impossible with ocean currents. Even though the velocity is only a few meters per second at most, that's a huge amount of strain that would constantly be on the structure, and then you have crap to worry about like harmonic resonances, like what destroyed the "galloping Girdy" suspension bridge. That might be cheaper than a full tunnel, but it sure doesn't look any safer...unless engineers could model that and design it perfectly. Plus we don't even know enough about sub-surface currents to even begin to speculate the behavior during all types of storms, as wave action influences currents by overturning water in terms of thermal and saline stratification, altering currents.

IN short, that would be an extremely chaotic system to model properly and design in a safe way to survive over long distances, for a respectable design life time.
Lurker2358
1 / 5 (2) Mar 03, 2012
Heck, it would be 1000 times easier to make vacuum trains all over the place on your own continent before you tried to make a trans-oceanic vacuum train.

I thought of using a magnetic propulsion system for SHIPS, which could be powered by enormous solar collection platforms. You'd put guide rails that the ships would float between, and the electromagnets would push against target plates on the ships, just like a maglev train works. This way you have off-board fuel and off-board engine for ships.

Unfortunately, it isn't very practical because the megastructure would still be expensive to build, though not as hard as a rail way. But large ships now use tugs when they get to port anyway, so their onboard engines are nearly useless on either end of the journey anyway.

So if you could power ships with off-board engines like this, you could save huge amount on fuel and cargo capacity.

It would take at least several decades for any such system to pay for itself.
jimbo92107
not rated yet Mar 04, 2012
Something about magnets gets all the boys talking crazy. I wrecked my grandma's TV with one of those things, so all I'm saying is, watch out!
TabulaMentis
1 / 5 (2) Mar 04, 2012
What about electric cars? Someone should inform the lightning GT developers.
Good point. That is one question many people would be interested in hearing an answer.