usenet weirdness

I've often thought you were dubious - but perhaps you were just doubtful. :-)

LEDs should have a warning label "do not stare into LED". They damage retinas. There are various LED technologies.

You know, like the old, "microwave oven in use" signs.

The "resonance" in "nuclear magnetic resonance" is "resonance theory's".

"Structural" or "molecular" chemistry is another example involving resonance theory, like "organic" chemistry, "resonant bonds".

The Tacoma Narrows bridge was another example.

There are some steel trestle bridges that happen to result that driving over them involves more than vertigo.

Heh, "remotely useful".

The usual idea of cavity resonators is common to microwaves and lasers.

Yes, but we were talking about medical imaging, not nuclear magnetic resonance in general, and your assertion is the irrelevance here, as the text you snipped pointed out.

Here there's that Faraday rotation basically puts a spin on Maxwell equations that otherwise are crossing lines.

I.e., there's an idea that all waves are spirals and all spirals are waves, with usual useful notions of wave mechanics as incomplete.

Differential equations are said to have "solutions", integral equations have "plane curves" (isoclines).

Most anywhere that D.E.'s or Diff. Eq's show up in applications, there are integral equations of feedback involved, the "differintegro" and "integrodiffer". To a, ..., "first-order approximation" though it's pretty usual. "Successful" theories like Einstein's Relativity, often their greatest claim is "first-order approximation".

The identity line is the envelope of the integral equations the linear fractional equation, and also both Clairaut's and d'Alembert's integral equations. Sort of like zero is often a trivial solution to Diff. Eq.'s, the envelope of integral equations is not really outside the bounds so much as "is" the bounds.

Kodaira, Zariski, and Lescop have more about that.

I was responding to a half-wit. If you integrate the total magnetic field strength across the bore of super-conducting coil, it is determined by the current circulating around that coil, but you can make arrangements that permit the local field to vary from place to place within that area. Faraday did like to talk about flux lines - it does make the idea easier to get across. I didn't try back in 1979 - we were being told about what was going on by people who had a high opinion of their own expertise.

The Batavia/Baikal neutrinophone communicated directly through the Earth with neutrinos, in about zero time.

Muons are sort of like Cerenkov radiation or Brehmsstrahlung/braking radiation.

So, one could convert "muons" to "neutrinos" and back.

Have you have of "deBroglie-Bohm"? Basically their ideas (or, mostly Bohm) about "real wave collapse" about the usual quantum formalism the Heisenberg-Scroedinger piucture: make for a different than the usual Copenhagen interpretation of quantum mechanics ("It's..., random") that it's not random and it's not discontinuous, instead since continuum mechanics.

Often enough that was called "hidden variables", then the word "hidden variables" was publicly shamed, so these times sometimes it's called "supplementary variables", though, people who stuck by their own idea of why nature's perfection would demand a continuum mechanics still have it often enough "hidden variables" to reflect on Bohm's origins of the ideas and not give it to the old-wrapped-as-new sort who didn't have to stand up for anything.

There's an ambiguity there. Calling somebody "dubious" implies that you have doubts about them. I have doubts about a lot of the claims made here, and spell them out explicitly from time to time - I'm dubious about them. That doesn't make me a dubious character, but rather one who questions what he he is told - which is to say skeptical.

Keep at it. You may eventually qualify as level 5 literate.

(Thanks for writing, I'm long inured to petty abuse on open forums due essential misunderstandings, or the tragedy of the commons, so you'll find that my machismo and bravado are essentially forgiving and will always make a generous reading.)

NMR was a fairly popular analytical chemistry business for a while. We made pulsed-field gradient coil drivers and temperature controllers for Varian.

But superconductive magnets and liquid helium are expensive, and other techniques took over. It was common to visit a lab that had a giant magnet in the corner, warm and collecting dust. A similar mass spec technique, FTMS, died for the same reason... too expensive.

Agilent bought Varian to get their medical stuff but immediately killed the NMR operation. I think Bruker still does NMR.

Hospitals prefer cat scans to MRIs these days. Cat scans are much cheaper.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

But we were talking about muons, not neutrinos.

They elementary particles, not photons - Cerenkov and Brehmsstrahlung/braking radiation is photons - quanta of electromagentic radiation.

"Sort of like" isn't all that informative.

"Muon decay always produces an electron (or positron) and two types of neutrinos".

If you had the two different types of neutrino and the electron and could contrive that all three collided you could - in theory - reverse the decay and end up with a muon. With only one neutrino, you couldn't.

The usual source of muons is cosmic ray protons hitting atoms in the upper atmosphere. It produces energetic - 6 GeV muons - which lose energy on the way down ground level where the average energy is down to about 4 GeV.

If you want make some, a laser-driven electron accelerator can offer a compact and tolerably high intensity source, if not one that would let you fake 9/11.

Read up on Bell's inequalities.

About as useless as "t'Hooft's Ladder".

Radiation can be polarised, and the plane of polarisation can rotate quite rapidly, in whichever sense you chose.

Faraday showed that a magnetic field can rotate the plane of polarisation of radiation travelling through a birefringent material.

The dimensions of the resonant cavity are a bit shorter in lasers. The cavity magnetron hasn't got a lot on in common with a gas laser.

The dimensions of the cavity in a cavity magnetron are lot closer to the wavelenght of the radiation being generation than space between the mirrors in a gas laser or the cavity defining interfaces in a a diode laser.

Powerful ones do.

Never seen one. Domestic microwave ovens are well shielded.

Only in the sense that some nuclei have a magnetic moment. If you bash them at the right frequency in the right magnetic field you can get the magnetic pole rotating at that frequency. There no fancy resonance theory involved.

I've got a Ph.D., in chemistry and while we got lectures on nuclear magnetic resonance, there was no fancy resonance theory involved in that either.

"Resonant bonds" are just a bizarre way of describing de-localised electronic bonds. Benzene has six carbon atoms arranged in a flat hexagonal ring, with one hydrogen atom hanging off each carbon atom . Traditional descriptions say that there are three double bonds and three single bonds around the ring - but that would make the three double bonds shorter than the three single bonds, and all six bonds are of equal length. Lecturers who were stuck in the traditional mind set liked to claim that the molecule resonated between two states where the double bonds and the single bonds swapped places rapidly. It was nonsense, but it kept them happy.

It's a famous example of an under-damped mechanical resonance - nothing more.

You can build in dampers to prevent the resonance from storing a lot of energy or distorting the structure beyond it's elastic limits.

These days mechanical engineers rely on computer simulations to let them anticipate this sort of problem.

Your idea of what might be "remotely useful" reflects more wishful thinking than any clear grasp of what is actually going on.

The earth's field is enough. The hydrogen resonance is about 4 KHz/gauss.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics