Superconducting NMR magnets

[douro20]

It's Rayleigh scattering. 

[LBpDC]

HOW DO THEY WORK!?

[BdanBlue]

I like your work :)

[sbscottmonkey]

Ln2 filling the dangerous way - using plastic hose. It can split when frozen - should use stainless steel braided hose instead.

[stefanmckinley]

Oh yeah! that's cool!

[7419635841635]

u think ur gonna get a +1 ? xD

[kworld01]

The cobwebs in some electric motors are the same as I find in my house. They are not done by spiders. Are we living in some kind of plasma field?

[kworld01]

Answer is the electric universe.

[twilight1138]

So, what IS your work ?

[wbeaty]

Electronics nerd, in the UW chem dept.

[darkcurrent]

hey, pretty cool.

I was using a oxford 400MHz NMR and I didn't see any liquid helium venting off... nor any of the valves condensing like yours... why?

[WoLpH]

Were you refilling the LN jackets? If not, than that's why ;)

[wbeaty]

Yep, LN refill. *Very* cold N2 gas is pushed out, and the entrained humid room air has a condensation cloud.

The blue color implies water droplet size of ~optical wavelength. Probably the immense temperature drop causes spontaneous condensation without nuclei. So rather than few large cloud-droplets, you get many smaller ones (more like molecule clusters than like droplets.)

Fog from the chilled metal looks white: fewer much larger droplets >> 700nM.

[wbeaty]

Idea to try: fill some hot wet air with condensation nuclei and pass it over chilled surface. Will the fog still be white?

[hyun0615]

Good Mr....

[Gicior]

I think Reyleigh scattering is the more commonly know name for it. If you want to get dirty with the equations perhaps name it Mie scattering.

[wbeaty]

> the electromagnetic radiaton like aged him 30 years in 30 seconds.

No, it's the eating dry ice that does it.

[glassspider66]

IN THE FIRST CLIP HE HAD HAIR!

the electromagnetic radiaton like aged him 30 years in 30 seconds.

see! science is EVIL....EVIIIIL i say!

burn him!!! burn the witch! :)

[chara1ampos]

LOL!

[ganjarific]

fuck yeah i love EM field theory. chem too!!!

super science forever muahahaha

[jasondubose2007]

MgB2 wire?

[nagualdesign]

So a magnetic field can strongly align a metallic object, whilst only weakly attracting it!

Are they two separate forces, then?

Fascinating stuff. ;-)

[wbeaty]

> Are they two separate forces, then?

Nope. If the magnetic field has about the same strength everywhere, then a ferrous object won't be pulled in any one direction. Yet if the field is strong, the object will be strongly torqued into alignment. Compasses twist into N-S alignment but are not attracted either north or south. Now if instead the flux lines spread radially outwards, then a ferrous object will be attracted, and will move towards the region of higher field.

[nagualdesign]

> Now if instead the flux lines spread radially outwards...

..As they do close to the source of flux, either end of a bar magenet, say? But further out the lines are more closely parallel? Or am I confused!

I've always had difficulty getting to grips with abstract concepts such as 'lines of force', somehow I'd be happier imagining particle densities or trajectories. You've got a pretty interesting job by the looks of it. Hope you love it. Thanks for the reply.

[wbeaty]

> ..As they do close to the source of flux, either end

> of a bar magnet

Exactly. But even with parallel field, if the lines are dense in one places and sparce immediately adjacent, then the attraction is strong. Math idea: "gradient of the field." A strong field can align iron objects, but it takes a field with strong GRADIENT to attract them. I always imagine that gradient means "spreading-ness" of the field, but parallel lines can also have high gradient.

[nagualdesign]

Thank you again, Waren!

[12creations]

0_0 I want one! How many teslas can this one go up to?

[SteelSpy1]

What are those superconducting magnets for?

[wbeaty]

They're used for Nuclear Magnetic Resonance analysis of tiny chemical samples. Sort of like MRI scanners, but with test tubes instead of entire human bodies. You can plot all sorts of resonance lines and electron coupling frequencies as 2D graphs, and in theory figure out the 3D shapes of molecules.

[SteelSpy1]

I find it fascinating that things this size are used to look at such tiny things... Just look at a molecule accellerator!!!

[ganjarific]

you dont need taht to figure out the shape of molecules just good knowledge of chemistry and ganja to help you think. wait scratch that, some things tooooo complex

[weezilla]

Typically, the spin states of protons (aka, hydrogen, +1/2 or -1/2) are equal in energy. The standard kind of proton NMR puts out a strong magnetic field, which creates forces on proton spin states so that they separate energies instead of being equal. Once the energies are "split," the NMR can send radiation through the molecules. Hydrogens in different types of molecules are split by different amounts, and absorb the frequencies based on how much they are split.