It is possible to magnify objects just using a magnetic field?

Tau.Neutrino said:

It is possible to magnify objects just using a magnetic field?

I’ll have to think about that one. I’d need to consider at least three things. One is that light is an electromagnetic wave. Two is that metamaterials can do interesting things, including magnifying objects. A third is that interesting things can be done with evanescent waves in the now growing field of plasmonics.

mollwollfumble said:

Tau.Neutrino said:

It is possible to magnify objects just using a magnetic field?

I’ll have to think about that one. I’d need to consider at least three things. One is that light is an electromagnetic wave. Two is that metamaterials can do interesting things, including magnifying objects. A third is that interesting things can be done with evanescent waves in the now growing field of plasmonics.

Does an MRI qualify as an answer to that question? An MRI allows people to see tiny things just by using a magnetic field.

Ah wait, I should have checked my Google first.

“Magnetic Metamaterial Superlens” finds an article in Nature. There’s one which is free access.

“https://www.researchgate.net/profile/Yaroslav_Urzhumov/publication/259652224_Magnetic_Metamaterial_Superlens_for_Increased_Range_Wireless_Power_Transfer/links/00463536bdb12ea1f5000000/Magnetic-Metamaterial-Superlens-for-Increased-Range-Wireless-Power-Transfer.pdf:https://www.researchgate.net/profile/Yaroslav_Urzhumov/publication/259652224_Magnetic_Metamaterial_Superlens_for_Increased_Range_Wireless_Power_Transfer/links/00463536bdb12ea1f5000000/Magnetic-Metamaterial-Superlens-for-Increased-Range-Wireless-Power-Transfer.pdf

Now this is a magnetic lens that can be used for generating beamed radio transmissions. It would have to be microsized to be used in the optical range.

> The superlens, which can refocus not only propagating far-field waves but also non-propagating, near-field waves, has been one of the more provocative concepts to emerge from the field of metamaterials.A superlens comprises a medium whose electric permittivity and magnetic permeability both take on the value of -1. The superlens structure offers a means of controlling and manipulating the near-fields that would otherwise decay rapidly away from a source. Initially, the superlens was proposed in the context of optics, where its use was suggested as a means of forming an image with resolution greater than that implied by the diffraction limit. The superlens functions via the excitation of magnetic and electric surface modes that couple to the near fields of an object placed on one side of the slab, subsequently bringing them to a focus on the opposite side. Since electricity and magnetism are nearly decoupled in the near field, it was realized early on that a superlens with either epsilon = -1 or mu = -1 could focus the near field of electric or magnetic sources, respectively. Imaging with a superlens has been demonstrated at visible and infrared wavelengths using thin layers of materials such as silver or silicon carbide whose dielectric functions take the value of epsilon = -1 at particular wavelengths.

> At low frequencies, where magnetism is much more prevalent …

Yeah. That reminds me that detecting and generating an electromagnetic wave by its magnetic (rather than electric) signature works best at low frequencies. Low even by radio standards. It would be better to magnify objects using electric currents rather than magnetism.

While talking MRI, how did anyone ever raise the money to make the first prototype MRI scanner?

Just imagine, the original proposal must have sounded like pure madness. Cooled by liquid helium. An orbiting superconductor. Flipping the spins of hydrogen molecules. Reading the flipped spins. Robotic control. Mathematically converting the convoluted readings into something that actually makes sense. Completely safe. Every hospital will have one.

I would have called for the proposer to be taken away in a straight jacket.

But it works, and now we couldn’t live without it. So who was it who actually had the brilliance to fund this?

mollwollfumble said:

While talking MRI, how did anyone ever raise the money to make the first prototype MRI scanner?

Just imagine, the original proposal must have sounded like pure madness. Cooled by liquid helium. An orbiting superconductor. Flipping the spins of hydrogen molecules. Reading the flipped spins. Robotic control. Mathematically converting the convoluted readings into something that actually makes sense. Completely safe. Every hospital will have one.

I would have called for the proposer to be taken away in a straight jacket.

But it works, and now we couldn’t live without it. So who was it who actually had the brilliance to fund this?

First two off the rank of my search.

http://www.two-views.com/mri-imaging/history.html

http://www.economist.com/node/2246166

roughbarked said:

mollwollfumble said:

While talking MRI, how did anyone ever raise the money to make the first prototype MRI scanner?

Just imagine, the original proposal must have sounded like pure madness. Cooled by liquid helium. An orbiting superconductor. Flipping the spins of hydrogen molecules. Reading the flipped spins. Robotic control. Mathematically converting the convoluted readings into something that actually makes sense. Completely safe. Every hospital will have one.

I would have called for the proposer to be taken away in a straight jacket.

But it works, and now we couldn’t live without it. So who was it who actually had the brilliance to fund this?

First two off the rank of my search.

http://www.two-views.com/mri-imaging/history.html

http://www.economist.com/node/2246166

My search: First prototype MRI scanner. History

mollwollfumble said:

While talking MRI, how did anyone ever raise the money to make the first prototype MRI scanner?

Just imagine, the original proposal must have sounded like pure madness. Cooled by liquid helium. An orbiting superconductor. Flipping the spins of hydrogen molecules. Reading the flipped spins. Robotic control. Mathematically converting the convoluted readings into something that actually makes sense. Completely safe. Every hospital will have one.

I would have called for the proposer to be taken away in a straight jacket.

But it works, and now we couldn’t live without it. So who was it who actually had the brilliance to fund this?

I don’t think so. MRI was derived from the well-established technology of NMR spectroscopy.

mollwollfumble said:

While talking MRI, how did anyone ever raise the money to make the first prototype MRI scanner?

Just imagine, the original proposal must have sounded like pure madness. Cooled by liquid helium. An orbiting superconductor. Flipping the spins of hydrogen molecules. Reading the flipped spins. Robotic control. Mathematically converting the convoluted readings into something that actually makes sense. Completely safe. Every hospital will have one.

I would have called for the proposer to be taken away in a straight jacket.

But it works, and now we couldn’t live without it. So who was it who actually had the brilliance to fund this?

Cripes. The true story of the development of the MRI macine reads like a thriller novel. https://en.m.wikipedia.org/wiki/Raymond_Damadian

Starting with research into sodium and potassium in test tubes, Damadian (somehow) found that tumours could be detected that way. Followed by hard slog, patent, full size prototype, theft of IP, gradual imaging improvements, failure of the machine to sell, patent “fights aplenty”, 129 million dollar settlement, lifetime achievement award, etc.

Even now, the thriller story is not finished, because as recently as 2017 a court ruled an MRI patent ineligible because it’s an “abstract idea”.

KJW said:

mollwollfumble said:

While talking MRI, how did anyone ever raise the money to make the first prototype MRI scanner?

Just imagine, the original proposal must have sounded like pure madness. Cooled by liquid helium. An orbiting superconductor. Flipping the spins of hydrogen molecules. Reading the flipped spins. Robotic control. Mathematically converting the convoluted readings into something that actually makes sense. Completely safe. Every hospital will have one.

I would have called for the proposer to be taken away in a straight jacket.

But it works, and now we couldn’t live without it. So who was it who actually had the brilliance to fund this?

I don’t think so. MRI was derived from the well-established technology of NMR spectroscopy.

Checking history of NMR spectroscopy on web. Yes, was well known long before the MRI proposal in 1969.

> The Purcell group at Harvard University and the Bloch group at Stanford University independently developed NMR spectroscopy in the late 1940s and early 1950s. Edward Mills Purcell and Felix Bloch shared the 1952 Nobel Prize in Physics for their discoveries.

When did liquid helium become an essential part of NMR? Or was it developed for MRI first?

The first NMR was done without superconducting magnets. The first superconducting magnets big enough to fit a human inside had appeared “by the end of the 1970s”.

Whilst I know this is considered focussing, not magnification in particular, think of particle accelerators. eg SLAC Adjusting the magnetics focusses the sub-atomic particle beam onto the tiny target.

Also, consider a CRT TV tube, which uses similar principals.

mollwollfumble said:

The first NMR was done without superconducting magnets.

During my undergraduate chemistry studies, I did an experiment involving a crude NMR device that anyone could build at home using an ordinary permanent magnet. The experiment involved detecting the proton resonances of water. This was about the capability limit of the device. To be useful to an organic chemist, the magnet would have to be far more powerful. Even at 90MHz, the information obtainable is fairly limited, which is why the technology has strived to develop more powerful NMR devices using more powerful magnets.

KJW said:

mollwollfumble said:

The first NMR was done without superconducting magnets.

During my undergraduate chemistry studies, I did an experiment involving a crude NMR device that anyone could build at home using an ordinary permanent magnet. The experiment involved detecting the proton resonances of water. This was about the capability limit of the device. To be useful to an organic chemist, the magnet would have to be far more powerful. Even at 90MHz, the information obtainable is fairly limited, which is why the technology has strived to develop more powerful NMR devices using more powerful magnets.

KJW, how powerful would your magnets have been?