discharging caps

Ask Professor Google.

The Varian NMR group did a little micro-imaging (we furnished the gradient drivers and temperature controllers) but most of the business was analytical chemistry, not imaging.

I think Bruker still does some analytical NMR.

Varian should have owned the medical imaging buisiness but blew that.

Kids often do NMR as a science project. The hydrogen line in water is huge.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

There was a lot of competition. There's a lot of money to be made in medical imaging, and the competition is cut-throat

On my calculator it was 0.2-(1/8) which is 0.075 and 1/0.075 is 13.33R. My Casio has an x^-1 key, which is handy. I think that was four keystrokes, but I didn't think too hard about it.

I've actually got an HP 10s scientific calculator in my desk drawer, but it relies on a solar cell to keep it charged, and I'd need to put it on the window sill in daylight for a few minutes to bring it back to life.

I'm pretty convinced NMR is alive and well. I wanted to hear from you what other technologies replaced it.

Jeroen Belleman

In your first part I see 9 keystrokes, then you need '=' to get the result. The last part if done retyping would need 7 + '='. If the calculator has memory, then presumably there is shorter seqence. On algebraic calculator with 1/x you need to type

Which is 7 keystrokes. On RPN calculator with 1/x you do

which indeed is 6 keystrokes. I do not think it matters much, people can press keys faster than they think. To say the truth, I use computer for similar calculations. I have command line history, so I can reuse previous commands, I can store results in variables, I can see several output together, I have real keyboard (and not tiny calculator keys). IMO much more convenient than what a calculator could provide.

You can do it at the Google command line too :)

As a sort of proof of intellectual life? John Larkin thinks that Donald Trump has "common sense". He's not exactly an intellectual power-house.

My first calculator was an HP9100

I still have one somewhere.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

One thing is tagging molecules with flourescent add-ons and counting single photons, on a surface or flowing though a capillary.

I've seen labs with a giant warm superconductive magnet in the corner collecting dust, because the budget couldn't afford liquid helium.

The big medical imagers are starting to include reliquifiers.

"Liquid nitrogen costs as much as beer and liquid helium costs as much as whiskey."

I spilled a lot of LN2 on the floor once and froze my knee.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

Probably just offered a good price for that division, by competitors.

A lot of that going on in biomedical diagnostics, with increasingly off-shore fab (like everything else).

RL

Well, rather you wouldn't want to go back.

I lost my 42s last year (left on site someplace) and was amazed at the prices they command on ebay. The swiss micro versions are cheaper than the originals, and are much more capable. However, they are still about £200 more than I would have liked to spend.

I ended up putting the rpn83 software on a TI-83 (cost about £10) and now use that when I'm out and about. Works very well. If I leave that somewhere it's no great loss.

I still have HP15's and HP48's in the office, but the HP42s was the goto.

That didn't work. I might take it apart, but I suspect that I won't bother.

You were lucky. There were hand-cranked mechanical calculators around the chemistry department, and we were required to use them to crank through at least one least squares data-fitting procedure (as well as collecting the raw data as experimental results). Melbourne University got it's own IBM 7040/44 about the time I became a graduate student, and as a graduate student I got to be a trained operator and could run it by myself on my own problems in the middle of the night. Technically we could book it from 11.00pm to 8:00am but the electronic engineers always booked the 11:00pm to 2:00am slot, and often the 6:00am to 8:00am slot.

Why?

It's not exactly an imaging technique. Single photon counting is slow.

Anybody sensible recirculates their helium.

But the atmosphere is full of nitrogen. Terrestrial helium is emitted as alpha particle by radioactive elements and can accumulate in in natural gas deposits (up to 7% by volume). There isn't all that much of it and you don't want to throw it away.

As a graduate student I kept the gas traps on my vacuum line cold with daily doses of liquid nitrogen

Nobody in the Melbourne University Chemistry Department was that clumsy. There was some spillage, but no frostbite that I knew of.

You must think and dream Trump all the time.

Sad.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

Medical MRI is such a beautiful invention. If there was something better, I'd expect to have heard of it.

Regarding the price of LHe, during the long shutdown of the LHC in 2019-2020, CERN *sold* its helium, and then bought it back when the LHC was about to be restarted! The LHC cryo system contains about 100 tons of LHe. I have no knowledge of the financial consequences of those transactions.

I don't know what they'll do this time around. The LHC was stopped in June and will undergo upgrades and repairs for three years to come.

Jeroen Belleman

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

Far from it. But his particular brand of ineptitude does resonate with yours. The local press does remind me about him from time to time - he does screw up remarkably frequently - but the US does have a lot of political clowns, and always has had. Weapons of mass destruction do come to mind.

It certainly would be, if it were true. Like most of your insulting speculations, it reflects your bizarre preoccupations, not mine.

Is that you?

I dare you to go a month without mentioning Trump.

Second dare, a month without insulting anyone. Or even a week.

Most of my non-winter preoccupations involve electronics. Yes, many are bizarre.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics