Science Questions

From where do magnets obtain their "energy" ?

Sun, 3rd Oct 2010

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Martin Elbin asked:

Why dont magnets ever "run out of power" to attract or repel?  ferromagnets in specific, i understand why electric current magnets keep working as long as there is a current, but alignment in ferromagnets dont use current, so why do they keep working...isnt this a contradiction to entropy?






Dave -   Okay.  In order to create a magnet, you’ve actually got to put some energy in.  Certainly, a permanent magnet. You've got to rotate all the low atomic magnets inside the piece of metal, piece of iron and rotate them all up and line them all up so their magnetic fields all add together.  And that takes some energy and a magnet does have some energy.  But for that to keep on going doesn’t require any energy.  It’s a bit like saying, “Why does the earth keep attracting us forever?”  They're just forces which exist forever.  The actual magnetism in a piece of iron or in a permanent magnet is actually caused essentially by electrons orbiting in one direction more than the other, and the electrons are going to keep on orbiting, as far as we know, for billions of years, as far as we know forever, unless something interrupts them.  So the little atomic magnet is going to carry on forever.  There’s no reason why the magnet shouldn’t carry on.

Chris -   It’s basically not burning off any energy to make the field and it’s something interacting with the field that actually makes an effect rather than the other way around. 

Diana -   But why is it then that some magnets get demagnetised over time?

Dave -   Okay.  The atomic magnets would stay magnetised, but especially if you drop them, you can cause them to re-align a bit every time you drop them.  If they get very hot, they can get re-aligned as well.  So, the atomic magnets is still there, but instead of all pointing the same direction, they start to become more and more randomly organised, so the overall field is less and less, and less.



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martin elbin asked the Naked Scientists: why dont magnets ever "run out of power" to attract or repel?  ferromagnets in specific, i understand why electric current magnets keep working as long as there is a current, but alignment in ferromagnets dont use current, so why do they keep working...isnt this a contradiction to entropy? What do you think? martin elbin , Fri, 1st Oct 2010

From the bonded ordered structure of the unpaired electron magnetic fields in the atoms.  Using a magnet to create forces that stresses the bonds that enable the fields and so can weaken a magnet  this is why horseshoe magnets have keepers and bar magnets are usually stored in pairs stuck together. Soul Surfer, Fri, 1st Oct 2010

To create a permanent magnet energy must be supplied to suitable materiel by immersing it in a magnetic field normally supplied by an electromagnet syhprum, Fri, 1st Oct 2010

I don't think magnets actually "store" power, nor do they consume power when they are attracting ferrous objects.

As mentioned above, permanent magnets are maded by aligning the atoms in the same general direction so that the fields produced by each atom add together to produce the force we observe. Prior to aligning the atoms, the individual fields are still there, but because they all point in different directions, the fields tend to cancel each other out.

If you turn a steel nail into a magnet in the manner that Syhprum describes, you can randomize the alignment of the atoms again by giving the nail a few good raps with a hammer. Heating it up will have a similar effect.
Geezer, Fri, 1st Oct 2010

Permanent magnets do in fact store some energy, place the magnet within a coil and connect a load to it, if you cause the magnet to demagnetize by some means the collapsing field induces a current in the coil and power flows into the load. syhprum, Fri, 1st Oct 2010

I never knew that! I suppose the alignment process must create some stress in the structure of the magnet. Geezer, Fri, 1st Oct 2010

Magnets are not consuming energy; the spin of the electrons within the substance of the magnet creates a field around the magnet, similar in some ways to the Earth's gravitational field that arises because the planet has mass. In both cases, an object placed within that field can interact with it, such as a stone taken to the top of a building - it has gravitational potential energy, but the energy had to be supplied by the stone being carried up in the first place. Similarly, a magnet creates a magnetic hill down which ferromagnetic materials can fall.

Chris chris, Sat, 2nd Oct 2010

The LHC magnets store 3.056 MW hours of energy quite a lot to get loose if the refrigeration were to fail. syhprum, Sat, 2nd Oct 2010

I think the real thrust of Martin's question might be more along the lines of

"What produces the force that permanent magnets exert?"

If that is the case, then one answer is the atomic alignment, but that doesn't really explain the source of the fundamental force either.

I think the fundamental force emerges from a property of space itself. Geezer, Sat, 2nd Oct 2010

Entropy concerns the flow of energy to maintan a force entails no flow of energy unless movement is produced.
I presume the field is produced by the exchange of virtual photons in much the same way as the force between quarks is produced by Gluons and the force between masses is produced by (gravitons ?).
I think we need a scientist here I am only a technician! syhprum, Sat, 2nd Oct 2010

Me too! Geezer, Sun, 3rd Oct 2010

Domain theory is what we were taught.  But it fails to explain were the magnetic dark force comes from.  Is it a property of the spare spaces in the outer electron shell do you think? Can you prove or disprove it??
CliveS acsinuk, Wed, 6th Oct 2010

Moving charges make magnetic fields.  The spins of electrons generally account for "moving" charges on a subatomic level, as Chris said.  The magnet is most stable when it can align these spins, which is why they all add up to produce a field instead of cancelling out. 

The explanation for how a force gets from the magnet to a piece of metal nearby is the usual one for electromagnetic force: classically its a field in space, while quantum mechanically its virtual photons (which arise from the field in space).  Does that help with the question? jpetruccelli, Wed, 6th Oct 2010

When considering questions like this it is very important to remember that all materials are very dynamic and contain energy over and above the mass energy of the particles that make them up.  let me describe them in ascending order of magnitude

The smallest is the thermal energy of the atoms and molecules in the structure as a result of the not being at the absolute zero of temperature.

Then there is the bonding energy for solids and liquids which hods the molecules together. When the thermal energy exceeds this solids melt and liquids boil.

Then there is the energy that holds the electrons in their orbitals around the nuclei.  This is where the magnetic effects reside in unpaired electrons in the structure of the material. When the thermal energy exceeds this gases ionise to become a plasma like the outer regions of a star at thousands of degrees K.

Then there is the binding energy of the nucleons in the nucleus.  When the temperature exceeds millions of degrees K as in the centre of a star or fusion reactor nucleosynthesis is possible.

Finally there is the binding energy of the quarks inside the nucleons themselves.  These have so much energy inside their minute confined area that their velocities are relativistic and the mass energy is less than the kinetic energy.  To release these you have to go back to before the first second of the big bang or use equipment like the LHC to create a quark gluon plasma. Soul Surfer, Wed, 6th Oct 2010

Me too!

Thanks JP syhprum, Wed, 6th Oct 2010

Maybe this one might shed some light on it? Magnets and fractals.
As well as this one superconductor-fractals.

And this one too, maybe? Origin of magnetic fields may lie in special relativity's SpaceTime distortions. This one is, as far as I can see, a pure hypothesis though, not experimentally verified. And in that way differing from the ones I linked above, considering the fractal nature of magnets/superconductors that are experimentally verified, as I understands it.

In it the journalist comments. "To get around this constraint, scientists have more recently turned to non-ideal dynamics. Researchers have looked at non-ideal mechanisms ranging from something called the baroclinic effect to processes stemming from inflation" So what are those non-ideal dynamics? Simply non-linearity, the way our SpaceTime actually 'works'.

Interesting 'move of perspective' that one. "Among fluids, two rough broad divisions can be made: ideal and non-ideal fluids. An ideal fluid really does not exist, but in some calculations, the assumption is justifiable. An Ideal fluid is non viscous- offers no resistance whatsoever to a shearing force." From the wiki:Fluid mechanics

So, are we at last starting to accept non-linearity then?
Wonder what that will do to our 'normalizations' and 'cut offs'? 
As for there existing no 'ideal fluid' as seen from that definition?
How about the 'vacuum', or rather what hides in it?
Or maybe not?

When we speak of a magnetic 'force' applied to the idea of an 'permanent magnet' I'm not sure what it is we talk about? When we talk about 'electro magnetism' and the way different charges can show more or less magnetic 'forces' I can see the relation though. But magnets are very strange, and interesting. :)

=== Add this one.

"PROVIDENCE, R.I. — At the quantum level, the forces of magnetism and superconductivity exist in an uneasy relationship. Superconducting materials repel a magnetic field, so to create a superconducting current, the magnetic forces must be strong enough to overcome the natural repulsion and penetrate the body of the superconductor. But there's a limit: Apply too much magnetic force, and the superconductor’s capability is destroyed. This relationship is pretty well known. But why it is so remains mysterious. Now physicists at Brown University have documented for the first time a quantum-level phenomenon that occurs to electrons subjected to magnetism in a superconducting material. In a paper published in Physical Review Letters, Vesna Mitrovic, joined by other researchers at Brown and in France, report that at under certain conditions, electrons in a superconducting material form odd, fluctuating magnetic waves. Apply a little more magnetic force, and those fluctuations cease: The electronic magnets form repeated wave-like patterns promoted by superconductivity.

The discovery may help scientists understand more fully the relationship between magnetism and superconductivity at the quantum level. The insight also may help advance research into superconducting magnets, which are used in magnetic resonance imaging (MRI) and a host of other applications. “If you don’t understand the quantum , how can you design a more powerful magnet?” asked Mitrovic, assistant professor of physics. When a magnetic field is applied to a superconducting material, vortices measured in nanometers (1 billionth of a meter) pop up. These vortices, like super-miniature tornadoes, are areas where the magnetic field has overpowered the superconducting field state, essentially suppressing it. Crank up the magnetic field and more vortices appear. At some point, the vortices are so widespread the material loses its superconducting ability altogether.

At an even more basic level, sets of electrons called Cooper pairs (named for Brown physicist Leon Cooper, who shared a Nobel Prize for the discovery) form superconductivity. But scientists believe there also are other electrons that are magnetically oriented and spin on their own axes like little globes; these electrons are tilted at various angles on their imaginary axes and move in a repeating, linear pattern that resembles waves, Mitrovic and her colleagues have observed. “These funny waves most likely appear because of superconductivity, but the reason why is still unsettled,” Mitrovic said.

Adding to the mystery, Mitrovic and fellow researchers, including Brown graduate student Georgios Koutroulakis and former Brown postdoctoral associate Michael Stewart, saw that the waves fluctuated under certain conditions. After nearly three years of experiments at Brown and at the national magnetic field laboratory in Grenoble, France, Mitrovic’s team was able to produce the odd waves consistently when testing a superconducting material — cerium-cobalt-indium5 (CeCoIn5) — at temperatures close to absolute zero and at about 10 Tesla of magnetic force. The waves appeared to be sliding, Mitrovic said. “It’s as if people are yanking on the wave,” she added. Mitrovic and her colleagues also observed that when more magnetic energy is added, the fluctuations disappear and the waves resume their repeating, linear patterns.

The researchers next want to understand why these fluctuations occur and whether they crop up in other superconducting material. The research was funded by the National Science Foundation and a European Community grant, as well as the Alfred P. Sloan Foundation."

yor_on, Wed, 6th Oct 2010

To get an idea at what I'm aiming at here you can research Mitchell J. Feigenbaum. and his Feigenbaum Constant.

That constant is one of the most remarkable phenomena I know of, and it's a purely mathematical concept, even if relating to almost anything physical in our 'real world'. And he got to it researching clouds :) Well, that's what he called it I think? Taking trips with various commercial airlines looking through that small window, wondering how those clouds could be so similar and yet so different. For some other constants, mainly for those 'mathematically inclined' needing their daily feed, have a look here. Food for U 'mathgeeks' :)

And here is a cool pdf Introduction to Chaos in Deterministic Systems. presenting the ideas. yor_on, Wed, 6th Oct 2010

There's not a lot of dispute that magnetic materials are somehow drawn towards each other. Is this because of an attractive force, or is it due to the absence of some repulsive force?

Either way, what is it that's doing the attracting, or not doing the repulsing? Geezer, Thu, 7th Oct 2010

Well, that seems to have pretty much put the kibosh on this thread  Geezer, Thu, 7th Oct 2010

You done killed it.

It's the electromagnetic field interacting with charges that either pushes things apart or pulls them together.  This field can either attract or repel--something that's due to the fact that the field is generated by, and interacts with two kinds of charges, +/-.  A field acting on uncharged matter will produce no force, and you'll also get no force if you have charged matter, but no field.  Is that what you were asking about? jpetruccelli, Fri, 8th Oct 2010

You really didn't think it was going to be that easy, did you? I'm interested in understanding what it is that actually communicates the force.

Are there particles involved, or is there some distortion of space-time? The forces produced are considerable, so whatever it is that communicates the force must be working quite hard. Geezer, Fri, 8th Oct 2010

I think JP has already confirmed my hunch that the force is mediated by virtual photons. syhprum, Fri, 8th Oct 2010

Ah! Well, they must be busy little characters then, so we ought to be able to observe them doing their stuff.

Might I also posit that the force is mediated by virtual bungee cords?
Geezer, Fri, 8th Oct 2010

Bungee cords would also use virtual photons to transmit the forces between their atoms.

See syhprum, Fri, 8th Oct 2010

Please pardon my skepticism Syhprum, but whenever I hear "virtual" anything, I subconsciously substitute "we really don't know what the heck's going on, but hopefully this will blind 'em with science".

We seem to be sufficiently clueless about the nature of actual photons, so it seems to me like a bit of a stretch (any allusion to bungee cords being purely accidental) to invoke virtual photons to explain anything. Geezer, Fri, 8th Oct 2010

Part of it's the "shut-up-and-calculate" nature of quantum mechanics.  It's weird, not necessarily intuitive, but it gets incredibly accurate results. 

But then again, can we describe classical fields in an intuitive way?  They're these "things" spread out over space that exert actions at a distance between objects.  We can understand them, certainly, but they're not particularly intuitive.

So if you apply quantum mechanics to fields you're making things doubly odd.  Initially, you get the interaction between objects via fields as some nasty expressions involving both objects coupling to the field and therefore to each other through the way they modify the field.  Virtual particles come about by trying to simplify these nasty expressions by extracting the most important contributions to them and writing them as something more intuitive.  I still think there's not a lot intuitive about photons, let alone virtual photons, but they're still a lot nicer to deal with than the original integrals. jpetruccelli, Fri, 8th Oct 2010

This is getting off-topic, but in some sense getting virtual particles out of quantum fields is a lot like getting classical mechanics out of the quantum mechanical waves of matter.  The motion of matter is technically described in QM by a nasty integral expression involving all possible paths the object could take.  However, if the object is large enough, the most important contribution to this expression is the one described by classical mechanics. jpetruccelli, Fri, 8th Oct 2010

Ah ha! In other words, they're a fudge to make the math work!

Seriously though, doesn't this suggest that we really can't properly explain how the forces are communicated?

BTW, I suspect this is very much what the OP was hoping to find an answer for. I've been asking this question for fifty years. Geezer, Fri, 8th Oct 2010

I think QM is a bit like miracles to religious believers, if you believe in an Omnipotent being that can make anything happen the world becomes very simple you just say it happens that way because god wills it.
I think QM is the best explanation available to the ungodly I think we need some more forbidden fruit to help us understand. syhprum, Fri, 8th Oct 2010

I think they can explain it.  It's just that the explanation and solution often requires very complicated expressions, and isn't all that enlightening: It's just treating the fields with quantum mechanics, which means you end up with a lot of quantum mechanical wave integrals.  There happens to be a good approximation that can be made and that approximation happens to have a nice(r) interpretation as something that's particle-like. 

There's another thing I didn't mention above: that is that the type of integrals which can be approximated with virtual particles show up a lot in quantum mechanical calculations involving fields.  Talking about virtual particles is also useful shorthand for these complicated expressions. jpetruccelli, Fri, 8th Oct 2010

I think it has to do with our natural limitations. It's impressive that we are starting to create words and ideas describing things we can't observe, but that we expect to be 'there' anyway. Our universe is changing into a concept where its origin becomes something not 'existing' to us, creating what we see as the 'reality'.

And no, I'm not religious, that much :) yor_on, Thu, 2nd Dec 2010

Suppose that on the other side of that building there was a very deep hole (e.g. a mine shaft) and you released the stone over that. It would not stop at the top of the hole, so there must be more gravitational potential energy involved than was put into the stone by taking it up the building. Bill S, Sat, 4th Dec 2010

I must confess that I do not understand how a magnet works.  Could it be a form of natural storage of electricity?  Thanks for comments.  Joe L. Ogan Joe L. Ogan, Sun, 5th Dec 2010

You could see it one of two ways Joe, or more? Who knows :) Either as 'forces' forcing 'transitions', or as 'emergences' creating 'new properties'. The second viewpoint gathers under chaos theory.

If you're working with particle physics you have some maxims, unstated mostly as I see it. One of them is that there will be 'forces', and that they are 'real'. Another is that that everything is created from 'discrete events' in SpaceTime, including magnetism. And the third I think is the 'background' on which those 'discrete events' is seen to happen.

If you think of it as fractal principles you don't really need 'discrete events'. What you need is 'relations' leading up to 'emergences', although those 'emergences' to us will have a shape and so can be associated with 'forces', making both point of views 'convertible' when over Plank size to me, Except for the maxims preceding them.

I lean to a 'mind-space' of principles, found to be 'real' through mathematics and experimentations that proves them to work at a practical plane. To see what I mean you can think of that 'time dilation' and 'Lorenz contraction' both are shown to exist, but on a complementary plane. You will only be able to see one of them, never both together. Only when thinking of that spaceship can you 'experience' both effects. That's the 'mind-space' we work from, to me that is  :) yor_on, Sun, 5th Dec 2010

The important thing to understand there is that the 'relations' is 'SpaceTime', no 'background' needed to it. Also creating the idea we have of 'discrete events' when passing a certain 'size'. That makes us like some 'foam' on, or in, a ocean of 'something else'. And it also allows for what what we call 'forces' to be created, without what we call the 'arrow of time' involved, on that 'plane below/inside/outside' whatever :) that may exist.

And there are no real 'borders' between it and us, just principles 'forcing' us into a certain way of seeing and experiencing SpaceTime. It allows for a lot more unexplainable phenomena than magnetism if you look at that way as neither motion, the arrow of time, distances and matter space and light are exactly what we think they are. Not on that 'plane'.

And it have to be organizational principles that 'puzzles it all together' what we see. The nice thing is that it allows for different 'puzzles' to me, and that I expect that there will be a principle for their 'creations' too hidden somewhere, maybe found as some weird constant to us.

Also it explains the question of why the properties of 'thingies' can be so different at different 'sizes', all as I see it of course :) yor_on, Sun, 5th Dec 2010

Hi, yor_on.  Now that really clears everything up.  If I could get someone to explain what you said, I am sure that I would understand it even better.  LOL Thanks for comments.  Joe L. Ogan Joe L. Ogan, Sun, 5th Dec 2010


Try this. All atoms are electromagnetic in nature. In "magnetic" materials, like magnetized iron, the crystalline structure of the iron aligns many of the atoms in a particular direction, so, you have a magnet.

What I'm not very clear about is how those magnetic forces are communicated through space. Geezer, Sun, 5th Dec 2010

Heh, you might be right Joe :) yor_on, Mon, 6th Dec 2010

You could look at this way, maybe :), from my point of view.

The 'force' of magnetism if it was 'relations', could be like someone standing behind a mirror (of water:), 'throwing a pebble'. For you on the other side of the mirror the 'pebble' won't be seen, but its effects will still show itself. The 'pebbles' are thrown everywhere though, in every magnetic line you see, and with all that we call 'discrete events' coming to be in it.



But not really, 'distance' and 'times arrow' is concepts on this side of the mirror, but on that other side it doesn't need to exist. But if it doesn't there still is needed to be some equivalence to it, that at last 'emerge' as our arrow of time, and distance. yor_on, Mon, 6th Dec 2010

I'm afraid that, despite my PhD including a certain amount of work on "magnetic materials", I can't offer any great insights or explanations (especially not now, 10 years on).

What I will say is that magnetism (or magnetic fields) is fundamentally related to electricity - in as much as any moving charge, including a wire passing a current, generates a magnetic field and will experience a force if that wire or charge is placed within some other magnetic field. It's a bit like saying that the magnetic field is a special kind of "turbulence" or "gust" which is caused by the moving charge or current.

To demonstrate this, you can take any piece of wire (nice copper wire). You know copper is not magnetic, can move it near a compass and the compass won't move. Now short that wire between the terminals of a small battery (an alkaline AA cell, C cell or D cell), and you'll find the compass moves when the wire is close.

Please only short the battery momentarily (no more than a couple of seconds at a time), use regular "alkaline" batteries only.
Never ever do this with any kind of rechargeable battery (NiCd/NiMH/lithium-ion/lead-acid etc) as you will probably burn your fingers and may even have an explosion!!!

One way or another, permanent magnets can be considered as entities with never-ending circulating current-flows.

People worry about how a magnet "keeps going", but actually if you think about the force (especially repulsive force) as more like compressing a spring... well no-one asks how a spring keeps "pushing back" forever without getting tired!

How about static electricity (electric charges)? We know you can pick up small bits of paper with a rubbed balloon - or stick said balloon to ceiling. Is that any more or less 'mystical' than magnetism? I guess magnetism is commonly rather stronger so seems more impressive! techmind, Wed, 8th Dec 2010

Ok, here is what I've gleaned....

First lets look at electromagnets. 

Any wire carrying current will create a magnetic field.  If it is a straight wire, it will follow the "right hand rule" with the thumb pointing in the direction of current flow (+ to -) and the fingers wrapped around the wire representing the magnetic field.

If you loop the wire, so the current travels in a circle, all the magnetic fields inside the loop are in the same direction, and one gets an electro-magnet. 

On an atomic level, the electron cloud around certain types of atoms can be oriented so that the orbiting electrons also generate a magnetic field. 

Three types of magnetic fields are possible.

1. Ferromagnetic - This is what we think of a permanent magnet.  Exhibits a strong, lasting magnetic field.
2. Diamagnetic - Rather unique.  Creates an anti-magnetic field.  Repulsed by all magnetic fields.  Only exists when around magnets.  Superconductors are Diamagnetic.
3. Paramagnetic - Exhibits a weak magnetic field, attracted to magnets.  Field dissipates in absence of an external magnetic field.

So, the "Ferromagnets" often contain Iron Oxide, but not necessarily.  The magnetic field is usually induced by a stronger magnetic field.  And, it is maintained by the orbits of the electrons.

The question comes up...  what is the smallest magnet that can be made.

So, can a single Iron atom become a magnet?

This actually came up in another topic.  Hemoglobin is an excellent example where a single iron atom (ion) is held more or less in a rigid place by a protein.  Depending on the oxidation state, it can be either weakly diamagnetic or weakly paramagnetic.  But, there is no way for it to maintain its electron orbit, and thus the magnetic field dissipates in the absence of an externally applied field.

Most magnets are actually compounds, mixtures, alloys, and ceramics. 
An example would be the basic "Ceramic Magnet" which is a mixture of Iron Oxide and either Strontium Carbonate or Barium Carbonate.

So, the "basic element" of the ceramic magnet is Iron Oxide (one of several), one Barium Ion(Ba2+), and One Carbonate Ion (CO32-).  Or, in the case of Magnatite, just Iron Oxide (Fe3O4), but actually is a two part mixture of Iron II and Iron III oxide (FeO·Fe2O3)

My interpretation is that applying a magnetic field to the Iron Oxide ceramic creates a resonance structure in that the electron spins of neighboring atoms/molecular elements.  This fixes the spin so that they do not return to a random orientation.  And, barring an external force, this resonance should endure essentially forever.  The smallest magnet should be a few dozen molecules.

The ceramic is disordered.  A crystal such as Magnetite is ordered, and likely holds its magnetization better. 

My interpretation is that a permanent magnet is a resonance induced in electron spins. CliffordK, Thu, 9th Dec 2010

Very nice thedoc. Solid matter physics sort of, like we had different densities where 'matter' had one, 'virtual particles' another. Those densities observable as unchanging for us gaining different kind of 'properties', defined by the 'densities' we can't observe. I like that. yor_on, Fri, 31st Dec 2010

I n my opinion it is likely a yet to be fully understood relationship to the electromagnetic for carrier photons.. Conservation of energy must apply if a magnet does work lifting an iron filling off a table it may weaken yet over time and a constant temperature and pressure it should gain from background photon bombardment the energy necessary to replenish less loss due to Entropy it steady state values. Recall; we are not taking about electron orbital promotion but rather effects that would affect things spectral broadening and possibly generalized positional uncertainty as well as internal momentum uncertainties.To get an analogous insight into these notions study Mass-Spectrometry‎. This is my opinion - I do not have PhD. Tom, Mon, 9th Nov 2015

Dave definition isn't accurate at all,the mechanisms of magnetism are still a mystery,he did not address the question.physicist admit that we don't know why magnets work ,we only know that they do and it has to do with an unbalance of should Google it yourself. Dre314, Tue, 13th Sep 2016

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