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Nuclear-Powered Cardiac Pacemakers

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Re: Nuclear-Powered Cardiac Pacemakers

#171

Post by clucas »

pxeger1 wrote: post #84
xtracto wrote: post #39

Earlier quoted context omitted.

Ooh, the Cobalt-60 incident in Mexico is also pretty crazy: https://en.wikipedia.org/wiki/Ciudad_Ju%C3%A1rez_cobalt-60_c... There were houses built of contaminated rebar! The story gets crazier the more you read about it.

It seems like an amazing coincidence that they were able to work out so much about how this happened. It makes you wonder how often this happens and noone finds out.

Nah, I think it would be more surprising if you couldn't track this stuff down. In the industrial and construction world, everything works off of POs and work orders. When a company buys or sells anything, there's almost always a paper trail, and usually some internal records showing what material went where. If you have the money to spend on the investigation (and an easy-to-detect signature in the material itself, like radioactivity) you can probably trace contamination all the way back to the hole in the ground it came out of.

Re: Nuclear-Powered Cardiac Pacemakers

#172

Post by bookofjoe »

ToddWBurgess wrote: post #50

If it is a dead body and it is being cremated you take it out so it doesn't explode in the crematorium. I say this as a former funeral director who had to remove them.

>Pacemaker explosions in crematoria: problems and possible solutions

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1279940/

Re: Nuclear-Powered Cardiac Pacemakers

#173

Post by xattt »

jackcarter wrote: post #64
OJFord wrote: post #32

Earlier quoted context omitted.

Just because you pay a positive non-zero amount for less than a quarter of the energy in, it does not mean that a device has greater than 100% efficiency, which is not possible. If heat pumps are 400% efficient then log burners in cabins in the woods are even better.

A heat pump warms a home more efficiently than using the same amount of electricity for resistive heating. It can do this because it's not generating the heat from scratch; it's moving heat from outside to inside. https://en.wikipedia.org/wiki/Heat_pump#Performance

A local company has developed a heat pump with a thermal energy storage system. Not sure how they do this, but I imagine there is some sort of insulated cinder blocks on a secondary loop that shuttles heat/cold to where it needs to go.

(1) https://stash.energy/en/product/

Re: Nuclear-Powered Cardiac Pacemakers

#174

Post by lucakiebel »

elliekelly wrote: post #170
ToddWBurgess wrote: post #50

If it is a dead body and it is being cremated you take it out so it doesn't explode in the crematorium. I say this as a former funeral director who had to remove them.

I'm curious whether it was standard practice for you to check for a pacemaker prior to cremation or whether the process relied on a family member informing you?

The doctors that sign off the cremation have to provide info on pacemakers/artificial joints and so on to the crematorium

Re: Nuclear-Powered Cardiac Pacemakers

#175

Post by MichaelCollins »

OJFord wrote: post #96
mminer237 wrote: post #55

Earlier quoted context omitted.

All energy from log burners comes from the fuel, and some ashes remain unburnt. They're under 100% efficient at converting fuel to heat. You put in x fuel and A heat pump takes heat from outside the system. You put in x fuel and you get >x heat. Getting more energy than you put in makes the efficiency over 100%.

I know. You can't just ignore the bulk of the input and still call it 'efficiency' though. Even manufacturers call this 'coefficient of performance', not efficiency.

Since precise use of language is so important to you:

> "You can't [...]"

He did, so obviously he can. You mean shouldn't, not can't.

Re: Nuclear-Powered Cardiac Pacemakers

#176

Post by jjk166 »

darwingr wrote: post #23

Could I use it to power my iPhone? Frankly I’m fed up with the need for charging.

For actual power, no it would be wildly impractical. However there is a concept of a nuclear top-off battery which keeps your main chemical battery from draining during long periods when not it use. So you could throw a charged phone in a drawer and come back months or years later and it's still good to go. Good for applications like an emergency kit.

Re: Nuclear-Powered Cardiac Pacemakers

#177

Post by sgtnoodle »

samstave wrote: post #159
sgtnoodle wrote: post #151

Earlier quoted context omitted.

Being pragmatic, that sounds way worse than just having a little ceramic 2.4ghz antenna and some extra silicon potted into the device!

https://www.dailymail.co.uk/news/article-2379009/Barnaby-Jac... - Oops - I didnt realize you were same poster from other comment

I don't think my particular pacemaker has the necessary circuitry to generate more than 5V, in pulses less than a few milliseconds. The voltage doesn't really matter much to the muscle.

If you got in you could probably put the leads into single-ended mode (so that there's more current path to cause mayhem) and pace my atrium and ventricles at 210bpm, and effectively give me a seizure. I can't imagine it would kill me before an EMS arrived with a magnet?

Perhaps a more nuanced attack would be to somehow use all the configuration parameters to intentionally bias the pulses so that there's net charge going into the muscle. Over a long time that would cause tissue damage.

If someone wanted to kill me overtly, a gun would be less work. A pacemaker malfunction that bad would be thoroughly investigated, and would be fixed in new devices within a year or two.

Re: Nuclear-Powered Cardiac Pacemakers

#179

Post by fennecfoxen »

NikolaNovak wrote: post #118
hwillis wrote: post #33

Earlier quoted context omitted.

You really should not. 60 beats per minute means that in ten years the leads of a pacemaker will be bent *315 million* times. That's an order of magnitude higher than we typically test fatigue resistance, and even if we were that confident about being able to produce flawless materials, there are millions of different enzymes and acids and temperature fluctuations in the body. Any one of those could impact the fatigu…

>>"changes size significantly when you sleep." Wait,what??

Brain neurons going into sleep mode eject some of the cell contents and shrink, which apparently also helps flush waste because the cerebrospinal fluid can flow better.

Re: Nuclear-Powered Cardiac Pacemakers

#180

Post by tengwar2 »

lake-view wrote: post #153
sgtnoodle wrote: post #98

Earlier quoted context omitted.

It sounds like you have quite a bit of knowledge on the subject. I had to get a pacemaker a couple years ago, and am an embedded engineer. I hope to live another 50 years at least, so this is an interesting subject for me. Maybe my cardiologist is just trying to make me feel good, but he says my leads will likely last 30-50 years. Intuitively that seems unlikely, but we'll see. It's got to be one of the most engineer…

> Maybe my cardiologist is just trying to make me feel good, but he says my leads will likely last 30-50 years. Intuitively that seems unlikely, but we'll see. It's got to be one of the most engineered cables in existence. One of my favorite learnings in school was about the "Endurance limit". Some materials, like aluminum, will eventually fail under cyclic loading even at tiny, tiny loads. This was a big problem whe…

Re passenger jets - I imagine you are thinking of the Comet 1? That was a more complex failure than is generally known. In brief, they did know about fatigue life at the time, and had ways of retiring aircraft before it was an issue (safe-life design, apparently introduced in the 19C for steam engines despite their being iron and steel). Ok, now you will be thinking "square windows, stress concentrators". Almost all pressurised aircraft use windows with angled corners in the cockpit. There isn't an intrinsic bar to square windows, and in fact the original design would probably have been ok. That used glued installation, avoiding stress concentrators. However a production engineer changed the design to use riveted installation, which caused the well-known problem with hull failure. Still, that would have been discovered if DH had not managed to resist government pressure to do fatigue testing on the pressure hull (because they were racing Boeing to be first to market, and fatigue testing takes time). They actually had the apparatus for repeatedly pressurising the hull in a bath, but only used it for testing static pressure.
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