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Only piston engines use AvGas, which contains lead but it's specifically Low Lead. They're slowy moving towards unleaded fuel but in aviation nothing moves fast. The risks are negligible compared to leaded fuel in cars.

I don't understand. What about the vast herds of migrating quadrupeds? They seem to manage pretty well.

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It is a good question. It is also true regarding both spinal disc herniation on nerve roots, and disc herniation on the spinal cord itself, that sensory pathways are involved far, far, earlier than motor pathways. And in fact, motor involvement is considered much more severe and is often what leads to surgical repair

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The other thing I frequently see called out about airplane engines is they run these power levels for hours on end. Typical car usage hits peak power for a very limited amount of time before dropping to something minimal.

Australia did have some megafauna. Thylacoleo was a masupial lion (101- 130 kg) roughly comparable to the weight of a lioness. They died out during the pleistocene and were Australia's largest known carnivorous mammal. There were also grazers such as Diprotodon (a kind of giant wombat), Palorchestes, plus a few others nearly all of which died out in the pleistocene

This whole thread started because someone brought up the potential future of EV planes. But people keep talking about todays solutions. Electric planes are in their infancy. Many battery technologies and other electrical energy storage technologies are rapidly solving the problems of today's batteries.

My best recollection is that sensory nerves are thinner and motor nerves are thicker. The short term paresthesia you get is actually from compression of arteries that give blood to the nerves. When the nerve has a loss of blood, it starts function poorly. The large motor nerves don’t get affected as quickly because there’s generally more blood flow to these and have more stores nutrients. Eventually though, a motor neuron will get affected, look up “Saturday night palsy” which is basically prolonged compression of the radial nerve I believe. Again, this is my recollection from PT school about 6 years ago, so it could be wrong🤷‍♂️

There’s already a non-leading alternate for 100LL AVGAS. As other people have stated, most really rich people do not fly in piston aircraft; they fly in jets which use a non-leaded diesel like fuel Jet-A. The new fuel has to be widely adopted, reach scale to reduce price, or there has to be a law outlawing leaded fuel in GA aircraft. We have laws banning leaded fuel for cars so creating a new law isn’t that far fetched.

This isn’t accurate. Motor and sensory nerves share a similar pathway. For example, look at the ulnar nerve (your funny bone). It splits at various points to give rise to partial sensation to your hand and partial to intrinsic musculature of your hand as well as some muscles of your forearm. This is just one example, but most spinal nerves have both sensory and motor function.

Isn't this the same as the Stanford lady and moving the light particles through empty space?

Sleeping on it is less likely to cause permanent damage because you're going to tend to move around enough that you probably won't cut off enough circulation or squeeze an individual nerve for long enough.

Where it can become an actual problem is for alcoholics and drug users who pass out to the point of total unconsciousness and don't move at all.

We don't go up to 96kHz because listeners can perceive it, but because it allows for the design of better filters, better processing, etc... which does result in better quality, but it'd be completely fine to then downsample in 48kHz right before sending to speakers.

It certainly can. It is all about how you look at things.

Someone can be concerned about drinking too much water, which I drink about 1 1/2 gallons a day and have never thought of, or someone can be concerned about all the alcohol people drink, how overweight everyone is becoming, or a number of things.

People were very concerned about covid and I'm still more concerned about driving than I ever was of covid. We all have our thing.

> So when talking about airliners, we're mostly talking about jet engines, which, by the way, are a subclass of turbines.

Turbine includes turboprops though, which are a significant minority of airliners and commercial aircraft.

Lots of gliders have done that in wave. Of course, that's off topic, since they typically have zero emissions.

ngl kinda seems like a r/GCSE question lol but the H+ ions are attracted by the charge through the water to the cathode where they gain electrons from the current to form H and covalent lay bond with other Hs form H2, and the rest of the water is a left as a hydroxide ion, OH-, which is turns into water and oxygen through the reaction: 4OH- -> H2O + O2 +2e-, so the oxygen is formed where the OH- ions react and the hydrogen is formed where the hydrogen ions gain electrons to become stable hydrogen molecules

Paresthesia due to compression is happening because nerves are compressed, not because of the sensory neurons in the skin. Thats the reason your feet are tingeling when you compress your upper legs by sitting on the toilet but you don't get paresthesia in your handy by carrying something heavy

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This is an interesting question! I knew a little bit about Transmissible Spongiform Encephalopathies from being a vet tech (scrapie in sheep & goats, CWD in deer, TME in mink and ferrets, and of course BSE/vCJD in cattle and humans— especially because I lived in Germany and the UK for big chunks of the 80’s and 90’s and so was banned from donating blood until very recently just in case I was a carrier myself!) but because I don’t work in a farm setting it’s not something I really need to keep up with so my knowledge is pretty shallow. This question got me googling and I found this interesting article:

Animals Resistant to Prion Disease: Intrinsic vs. Extrinsic Factors

https://www.frontiersin.org/articles/10.3389/fncel.2020.00254/full#h3

It’s super long and gets very technical at times so I will freely admit that I skimmed big chunks of it, but my “Today I Learned” takeaway is: horses, dogs, and rabbits are very highly resistant to prion disease, as in not developing disease even when injected directly into their brains, let alone when being fed contaminated material. I knew so many different species had their variants (though I also knew not all diseases seem to be able to cross to all species), and that we have evidence of cats and zoo animals becoming ill during the BSE outbreak, so I think in the back of my mind I had an assumption that all mammals would be at risk.

Dogs being resistant makes sense to me— they’re highly generalized scavengers whose whole schtick is being able to thrive on whatever garbage they find lying around, lol. But horses and rabbits are both infamous for being so medically fragile! I guess now I know what superpower they traded away everything else to gain… (/facetious in case that wasn’t clear!)

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Student pilot here, the industry is in the process of moving in that direction. There's a lot of barriers that are slow to get past.

The first thing to understand is that the aviation industry moves slowly and purposely. If a car dies on the highway you coast to the side of the road and usually don't cause an accident. When a plane's engine has a failure that plane is going to need to land somewhere. There's a much higher risk of that causing death and property destruction. Sometimes you're over farmland and get lucky, sometimes you're not. Just google "plane crashes into house" to get a sense of it. There's many many other things that can happen when a plane's engine dies. Because of this the FAA takes slow deliberate steps in changing regulations. One of these is how they certify which engine in which airframes using which gas are permitted. Changes to this need to be certified by someone and for a long time no one had the incentive to do this. I believe getting unleaded fuel certified for most general aviation planes and engines took a change in the way they regulated this, possibly from political pressure.

Next, someone needed to develop an unleaded fuel that can run in existing airplane engines, and there needs to be refinery and distribution capacity. Most planes need 100 octane fuel. While many engines could run 94 octane many need 100 octane. Development on 100 UL didn't start until 2010. FAA certification didn't happen until July 2021 for a single plane (Cessna 172) using a single engine manufacturer. Last September they finally certified it for all planes and engines, though the owner or operator of the plane needs to get a supplemental type certificate for their plane (don't ask me why). Every owner/operator of a piston engine aircraft needs to pony up about $600. Great, except it's not available yet. The developer of the fuel needs to ramp up production capacity and distribution. This is where we are currently at. It's expected to be available in California next year and around the country in 2026.

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The next thing is that airports need to start stocking unleaded fuel. Until there are absolutely no planes that require leaded fuel airports will need to stock leaded fuel. Airports serve a public purpose to the flying community by making fuel available. You don't want to leave a big gap in the us where a pilot flying from point A to point B can't get the fuel they need. Now they need to keep another type of fuel. This requires new tanks and either new pumps or trucks. This will be the next roadblock.

If you want to learn more about general aviation you can do what pilots all do and listen to AVWeb’s Paul Bertorelli.