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Old 26th October 2022, 09:29 AM   #41
crescent
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Originally Posted by RecoveringYuppy View Post
I'd be pretty sure that some balloons can be floated with 60/50 or 50/50 especially if you don't care for how long. But that first guys claim of 20/80 seems off. I'll double check his numbers later.
I'm wondering if he's assuming regular air pressure. In a balloon the air pressure is higher - not a huge difference but enough to affect density.

Take a Mylar balloon that has lost enough helium to barely be buoyant. Put it in the shade, it sinks. Put it in full sun, it warms up and that can be enough to expand the gasses a bit and make it float again. It doesn't take much change in pressure to affect density enough to affect the lift of something as low-density as an inflated balloon.

Altitude would be at play as well. A mix that's just enough to float a balloon in Los Angeles might not be enough to float a balloon in Denver.
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Old 26th October 2022, 01:07 PM   #42
RecoveringYuppy
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Originally Posted by crescent View Post
I'm wondering if he's assuming regular air pressure.
That's one problem. Two of the articles are only assuming neutral buoyancy and no lift and not allowing for leakage. So not a satisfying customer experience. What's the point of helium balloon that isn't guaranteed to rise to the ceiling or lift a string and a small toy soldier?

However it's now pretty clear a precise answer to how much we can save in balloons isn't really relevant. Balloons are a small part of the issue and it's pretty clear that any helium supply that can satisfy our other needs is going to be be able to satisfy balloon demand as either a byproduct or recycled from primary uses.

The real issue is that a subsidized source has gone away couple with the problem that some current sources are being wasted rather than harvested.
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Old 26th October 2022, 07:54 PM   #43
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NMR spectroscopy and chemical research

Nuclear Magnetic Resonance (NMR) spectroscopy is a cousin of MRI, and it also requires liquid helium. With out NMR spectra, several branches of chemical research, especially organic chemistry, would drastically slow down.
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Old 30th October 2022, 03:07 PM   #44
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Originally Posted by casebro View Post
A mix of helium and hydrogen would be harder to light then pure hydrogen....
At the risk of nitpicking pure hydrogen won't ignite, it needs o be mixed with oxygen or another oxygenating agent, such as chlorine or fluorine. For standard air mix a mole% of 3.8 is generally taken to be the lower limit for explosive risk and 76 the upper limit.
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Old 30th October 2022, 03:15 PM   #45
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Originally Posted by RecoveringYuppy View Post
I'd be pretty sure that some balloons can be floated with 60/50 or 50/50 especially if you don't care for how long. But that first guys claim of 20/80 seems off. I'll double check his numbers later.
Assumptions: one mole of air is taken to be 29g, an average balloon to be 12 litres and weighing 6 grammes, and molar volume at RTP to be 24 litres.

Balloon holds one-half mole or 14.5 grammes air. To allow aerostatic lift this needs to be reduced to 8.5 grammes so what proportion of helium (4g/mol) needs to be substituted for the air?
A 50% mix will work (mass 8.25g) however that's about the minimum limit.
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Old 31st October 2022, 07:21 PM   #46
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medicinal chemistry would slow down

Originally Posted by Chris_Halkides View Post
Nuclear Magnetic Resonance (NMR) spectroscopy is a cousin of MRI, and it also requires liquid helium. With out NMR spectra, several branches of chemical research, especially organic chemistry, would drastically slow down.
It would be far more difficult to make the next Paxlovid or Remdesivir without H-1 or C-13 nuclear magnetic resonance spectroscopy. P-31 and F-19 are often helpful as well, but they are more limited in the number of compounds to which they can be applied. Mass spectrometry is a powerful technique in its own right; therefore, I won't say that it would be impossible to make the next generation of antivirals.
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Old 1st November 2022, 07:09 AM   #47
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Originally Posted by RecoveringYuppy View Post
I'd be pretty sure that some balloons can be floated with 60/50 or 50/50 especially if you don't care for how long.
This is why I realized that it's a mixture. The last He balloons we got only floated for about 12 hrs before they dropped. They used to last a lot longer than that, and would last for a day or more. It was clear that the He was diffusing away faster, and I didn't expect it to be a difference in balloons, so it must have been they started with less He.

It also made sense that the price hadn't gone up. Given the price of He these days (a 99.999% cylinder used to be $40 back in 1990, is not over $500), the way to keep prices done is to have less He
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Old 1st November 2022, 11:01 AM   #48
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Originally Posted by pgwenthold View Post
This is why I realized that it's a mixture. The last He balloons we got only floated for about 12 hrs before they dropped. They used to last a lot longer than that, and would last for a day or more. It was clear that the He was diffusing away faster, and I didn't expect it to be a difference in balloons, so it must have been they started with less He.

It also made sense that the price hadn't gone up. Given the price of He these days (a 99.999% cylinder used to be $40 back in 1990, is not over $500), the way to keep prices done is to have less He
Back in '99 I was at an Xmas party and discovered that an average balloon could lift an empty sort drink can. Some of them were still floating the new year.
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Old 6th November 2022, 02:10 PM   #49
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Pure hyperbole

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