The gas inside a standard party balloon is generally compressed 3% to inflate the balloon. This wipes out even the theoretical buoyancy of nitrogen. And trust me, there was never any practical buoyancy to begin with. You’d need a ridiculously large balloon in a room with impossibly still air and impossibly null thermal gradients to even measure the buoyancy of nitrogen vs air. The buoyancy of nitrogen vs air would never be perceptible to human senses in any real-world setting.
It would be the same as just filling the balloon with air.
I'm 20+ years out of college and I asked a question specifically because I was unsure. Give me a break. I'm sorry if "party balloon buoyancy physics" wasn't the part of my college classes that stuck with me.
You probably do, actually! People constantly underestimate the grand utility of their basic education.
At near-atmospheric pressure and typical ambient temperatures, the ideal gas equation (PV=nRT) from introductory physics works very well and indicates that a 3% overpressure would make gases 3% more dense (linear direct proportionality). At some threshold of high pressures/ low temperatures, you'd want to switch your equation of state (EOS) from ideal gas law to something else. Peng-Robinson would be a good choice for a non-polar gas like Nitrogen, if its >10-50 atm pressure and/or < -50C temperature.
At 20 degC, 1.00atm to 3kPa gauge pressure, ideal gas law predicts nitrogen would increase in density by 2.9608%. Whereas Peng-Robinson predicts it would increase in density by ever-so-slightly more, 2.9623%. This is truly negligible, so better to use the simples EOS for explainability (which would be the ideal gas law).
More than just from inflation? (sorry, not sorry!)
You have the entire collected knowledge of mankind at your fingertips. You could do 30 seconds of research and find an answer better than "I don't think that sounds right".
So could you, right?
(The form in which Christopher Hitchens actually stated "Hitchens' Razor" is more symmetrical but unfortunately wrong: "What can be asserted without evidence can be dismissed without evidence". Anything can be asserted without evidence! It's only when something actually has been, in a given context, that dismissing it is -- in the same context -- a reasonable course of action.)
In this case it would be reasonable to inquire about the basis of the original remark, or to reject based on personal knowledge, or to reject based on a concrete citation. But an arbitrary non-technical vibes based rejection doesn't fit with how things generally work here.
What is the reason that MRI needs grade 6 vs grade 4 helium? I'm imagining that the superconducting wire is within a cryostat filled with liquid helium. Doesn't seem like there would be any appreciably partial pressure of things like nitrogen or oxygen at 4 Kelvin. I imagine the reactivity of oxygen is pretty low at 4 K as well. How much dissolved oxygen or nitrogen can liquid helium support? And how much solidifies out and sinks to the bottom of the cryostat?
Turns out that you are right, some balloon gas is 80%. Specifically, the "Balloon Time" tanks you can buy at places like Target say "not less than 80%" helium.
On the other hand, I went to AirGas and a few other suppliers and they seemed to have 95%-97.0% helium gas as their definition for balloon grade.
Definitely worth knowing what you're getting, in any case, so you don't get ripped off, and so you can actually get that lawn chair contraption into the sky.
Obviously you can't have oxygen in welding gas; it would oxidize the shit out of everything.
A little bit of oxygen in party balloon gas is beneficial. Some kid will breathe it, and when they do, you didn't want them to asphyxiate themselves.
Grade 6 (6.0 helium = 99.9999% purity) The closest to 100% pure helium, 6.0 helium is used in the manufacturing of semiconductor chips – Grade 5.5 (5.5 helium = (99.9995% purity) Like 6.0 helium, 5.5 ultra pure helium gas is typically considered “research grade,” also used in chromatography and semiconductor processing
Grade 5 (5.0 helium = 99.999% purity) This high purity grade helium is also widely used for gas chromatography, mass spectrometry, and specific laboratory research when higher purity gases are not necessary, as well as for weather balloons and blimps.
Grade 4.8 (4.8 helium = 99.998% purity) The highest of the “industrial grade” heliums, 4.8 grade helium is often used by the military. The rest is classified...
Grade 4.7 (4.7 helium = 99.997% purity) A “Grade-A” industrial helium, 99.997% helium is mostly used in cryogenic applications and for pressurizing and purging
Grade 4.6 (4.6 helium = 99.996% purity) Grade 4.6 industrial helium is used for weather balloons, blimps, in leak detection
Grade 4.5 (4.5 helium = 99.995% purity) Often the grade most commonly referred to when people say “industrial grade,” 99.995% helium is most commonly used in the balloon industry
Grade 4 (4.0 helium and lower = 99.99% purity) Any helium that is 99.99% and down into the high 80 percents is within the range of purities referred to collectively as “balloon grade helium.”
"most distributors simply stick to the industry standard transport of Grade 5. That is why for and [sic] end user of helium, a lower grade can cost more than the higher grades."
Moar hydrogen party balloons. Making partying fun again!
It's been coopted, not necessarily capitalism means "everything should be private", the current flavour of capitalist ideology wants that but other versions of capitalism don't put that as a foundational Ideological tenet.
After 30 years of empirical reality demonstrating that if you want a government that is responsible with money, you must vote democrat, Donald Trump was still voted in because "He's good for the economy"
He is not.
In the 1980s, I assume getting rid of the "strategic reserve" of anything would have met more pushback, because of primal fear overriding greed.
Kidding aside, the US has had libertarian pipe dreams for the better part of its history. The aberration was the New Deal period up until the mid 60s.
– Georgi Arbatov, Soviet political scientist, 1988
Sounds like Obama kept the gas taps flowing, instead of locking it up because authorization to sell it had expired. Here is the whole record: https://www.congress.gov/bill/113th-congress/house-bill/527/...
> biden
uhm...
There are billions of people in the world, and you are one, and you have your one set of opinions out of billions.
Nobody endowed you or your opinions with any sort of infallibility or superiority over others.
Words have meaning. Someone a bit left of a Nazi is not on the Left even if they are to the left of the person speaking.
The Democrats are a right-wing party. They spend more energy attacking the left than they do, the Republicans. Look at what they did to the center-left Sanders and their constant lawfare to keep left parties, like the Greens and Peace and Freedom, off the ballot and out of the debates (last election, the Greens spent half their campaign funds fighting these frivolous lawsuits from the Democratic party who seek to subvert democracy [Republicans attack anyone more left/darker than them, through voter suppression and other techniques to also subvert democracy]). There is very little daylight between the two. They serve the same masters, Oligarchs and Israel.
The United States is also a one-party state but, with typical American extravagance, they have two of them. - Julius Nyerere
After sales paid off the debt that has been incurred from the expansion of scope of the helium program in the 1960 Helium Act, which was one of the main points of the HPA, it was update by the Helium Stewardship Act of 2013 (which passed the House 394-1, and the Senate 97-2, and was signed by President Obama).
https://radiology.ucsf.edu/patient-care/patient-safety/mri-s...
> If the scan room door is closed when a quench occurs and helium escapes into the scan room, the depletion of oxygen causes a critical increase in pressure in the room compared with the control area. This produces high pressure in the scan room, which may prevent opening of the door. If this should happen, the glass partition between the scan and control rooms should be broken to release the pressure. The scan room door can then be opened as usual and the patient evacuated. In such a case the patient should be immediately evacuated and evaluated for asphyxia, hypothermia and ruptured eardrums.
My point is that there's "maximally efficient / profitable" versus "can be made available as an emergency alternative".
Cooling to 14 K isn't the cheapest option, but it has very low complexity. You can "simply" pressurise the source gas, cool it to room temperature through an ordinary heat exchanger, then allow it to expand. The only issue is that if you do this naively, the expansion nozzle will get clogged with ice.
Obviously, this wastes a lot of Helium, but we have lots of it. If what's needed is high purity Helium, then throwing away even 90% to get 10% that's 6N pure should be no problem for an industrial nation.
However, any air (or gas) liquefaction / separation plant that is already making purified industrial gases from air or other sources could be adapted in a matter of weeks or at most a couple of months.
We have so much gas where I live that there are places it’s just flared off and burned, because it’s less greenhouse emissions than it escaping unburned.
https://www.britannica.com/science/chemical-element/Processe...
Granted, the flare gas probably doesn't reach the prerequisite 100M-200M kelvin. I suspect high pressure is also required so the Helium stays close to the heat source.
https://www.minnpost.com/other-nonprofit-media/2024/07/what-...
One’d think that they’d keep more than a couple of weeks’s supply of critical materials —to bad many copied Cook’s and others’s JIT inventory management for everything.