Super cool! Looking forward to future posts in this series (any chance you're going to do one on metamaterials?)
Microscopy on an endoscope brings up another idea: could we record and control the brain better if we mounted fNIR or ultrasound hardware on a stentrode inserted into a blood vessel?
Kind of tangential, but here's something that confuses me. In the 80s people discovered high temperature superconductors, cooled by liquid nitrogen, rather than liquid helium. They were supposed to revolutionize things, but they didn't. I could imagine that they have serious drawbacks and literally no one uses them, but, actually, 10-20% of medical MRI machines use them. How can the two types coexist rather than one outcompeting the other? Is there some niche? Maybe smaller, relatively portable machines? Not the ones you're talking about, but a previous generation. As far as I can tell, they use helium, too. Perhaps some other niche?
I was wrong. Absolutely no one uses nitrogen cooled MRI machines. No one uses nitrogen cooled superconductors for any magnetic application. There are a handful of nitrogen cooled superconducting power lines, but almost all application of "high temperature superconductors" is actually at low temperature, to get different parameters than old-fashioned superconductors. I suggest that people say "ceramic superconductors" when the point is that they are different and not that they are operated at high temperatures. (Possibly the high critical temperature is relevant, in that operating very far below it is relevant.)
But it is true that 10-20% of medical MRI does not use cooling. I think the niche is for small clinics in rural areas that can't amortize the cost of cooling and instead use a high operating cost electromagnet. But I also hear about permanent magnets. If permanent magnets already had even 5% of the market, why wasn't that experience enough to expand into the ICU niche before now? I suspect the answer is that this could have been done 10 or 20 years ago.
Super cool! Looking forward to future posts in this series (any chance you're going to do one on metamaterials?)
Microscopy on an endoscope brings up another idea: could we record and control the brain better if we mounted fNIR or ultrasound hardware on a stentrode inserted into a blood vessel?
https://en.wikipedia.org/wiki/Stent-electrode_recording_array
Kind of tangential, but here's something that confuses me. In the 80s people discovered high temperature superconductors, cooled by liquid nitrogen, rather than liquid helium. They were supposed to revolutionize things, but they didn't. I could imagine that they have serious drawbacks and literally no one uses them, but, actually, 10-20% of medical MRI machines use them. How can the two types coexist rather than one outcompeting the other? Is there some niche? Maybe smaller, relatively portable machines? Not the ones you're talking about, but a previous generation. As far as I can tell, they use helium, too. Perhaps some other niche?
The high temperature ones have lower critical magnetic fields unfortunately
I was wrong. Absolutely no one uses nitrogen cooled MRI machines. No one uses nitrogen cooled superconductors for any magnetic application. There are a handful of nitrogen cooled superconducting power lines, but almost all application of "high temperature superconductors" is actually at low temperature, to get different parameters than old-fashioned superconductors. I suggest that people say "ceramic superconductors" when the point is that they are different and not that they are operated at high temperatures. (Possibly the high critical temperature is relevant, in that operating very far below it is relevant.)
But it is true that 10-20% of medical MRI does not use cooling. I think the niche is for small clinics in rural areas that can't amortize the cost of cooling and instead use a high operating cost electromagnet. But I also hear about permanent magnets. If permanent magnets already had even 5% of the market, why wasn't that experience enough to expand into the ICU niche before now? I suspect the answer is that this could have been done 10 or 20 years ago.
Excellent 🔥🔥