J.C.MacSwell

I thought to myself how long it might take you to realize it if I brought it up...I figured under 10 seconds...so I saved some typing

You might want to rethink that

This is something akin to grabbing a tiger by the tail...generally best to keep your distance instead But it's a great question

Not sure. Do you mean when you succeed in getting the image?

I saw the Wiki on that (averted vision) Apparently Aristotle used the technique. I had not heard of it before. Not exactly what I was thinking but obviously related. I have heard that peripheral vision is better with movements, where the centre is of course better at definition.

My guess is that it is useful to defocus visually when you want to focus mentally on the periphery of your vision, possibly in one area of the periphery or possibly for the appearance of something, say when hunting or even fighting). I really have nothing to back that up other than to say I feel it works for me (not that I hunt or fight, but in a number of similar ways). It is a related technique to "glancing around" but I (feel again) it has advantages in some circumstances, and sometimes switching back and forth between the two techniques. I'm not sure everyone doesn't do this whether they realize it or not.

I did find this https://www.naturalnavigator.com/the-library/tidal-streams-and-tidal-currents Based on that your thinking seems to be a UK thing more so than scientific/non scientific But it is pretty much regarding our debate. I am still surprised I have never come across it before.

OK. I understand. Tidal stream is the better and more specific term. But seriously "currents" is a very generic term that covers it also. You are welcome to disagree, but also welcome to provide a link with a definition of tidal stream that does not use the word "current" in the definition. (note the Wiki above) Where I come from tidal currents or tidal stream are almost interchangeable, tidal stream just implying a larger flow (that part totally anecdotal and not that that has any bearing on this whatsoever but I stand by the above, with all due respect have never heard of "currents" being limited as you suggest, and have used and heard the term from many different contexts...I just got home from a shipyard...I don't know what else to say except I would be very interested in being corrected...feel free)

Gotcha...so it's not your heavy day workout for the week!

I think you can assume 100% humidity in those conditions. Since your source is at 1 bar and assuming it all goes in until it is 3 bar (2 bar gauge) wouldn't 2/3 of the vapour have condensed out once the tire gets back to ambient temperature? Edit: Manual pump for installing 4 tires? I wouldn't want to mess with you!

I would be telling you I have never heard of the term current excluded due to lack of permanence of any kind. Tidal currents, wind blown currents, etc. Are these not common terms? I have studied currents, for years racing sailboats, including internationally, and live near the Bay of Fundy. I have never heard of "currents" being restricted as you are suggesting. Tidal stream From Wikipedia, the free encyclopedia A tidal stream can refer to two different phenomena: in marine science it refers to the currents associated with the tides, generally near a coastline or harbor

Right so 2 bar gauge is 3 bar. Should the drop not then be closer to .45 bar? (22.5%)

Both are not currents? Where did you get this from? I would think tidal streams are a subset of currents.

If I am taking this correctly that is about a 30 percent drop in gauge pressure with just 2 percent attributed to change in state of water for the 45 degree drop. The problem is exacerbated at higher temperatures, especially when free moisture is available to vapourize. If you fill the tire using air at 35C (starting point for John Cs benefit) and 100 humidity a 10 degree change, plus or minus, can produce almost as much pressure difference again as in the case of dry air. If moisture still remains at 45C the effect can become equal or greater as the tire heats up further. I know free moisture should not to be in the tire but I suspect with many tires that could be the case (though more likely when the tire is cooler)

I knew you would get it...but +1 for explainining

I guess it is impossible to drive a combustion engine car at -25 C so the tires would not heat up anyway.

So you didn't understand? You thought I meant that it heated up, but stayed at the same temperature? That's what you got out of it?

OK. So you could not infer from my explanation that it was -25 C ambient condition and when the tire heated up, as it must, it (the tire) was...no longer -25C?

...on a typical -25 degree day...while/after driving...liquid moisture in tire...are you having trouble with the context of the wording or the science?

The effect is additive so can still be significant. Let's say you fill up your front tires with air from a compressor on a hot humid day in the summer time. You make sure to make the pressures equal. You do the right side of the vehicle with dried air but the left you simply compress air and pump it in moisture and all. Drive for a while and the pressure increases in both tires as they heat up but will be greater for that on the left. Wait for a cold day in the winter and both tires will have dropped in pressure but again the difference will be greater for the left, as some of the vapour will have condensed. The main point of course is that that left tire can in fact have liquid moisture in it at -25 C. It could be quite likely to under driving conditions after it is warmed up...something you assumed was not the case when you jumped on MigL...unless of course you knew it all along but thought it was still OK to think he claimed the "water is liquid at -25" when that was not what was stated, whether his wording was in error or not.

Non classical agreement...

Depending on the tires, speeds and loading, driving for half an hour at -25C could easily raise the tire temperature above the melting point of water. https://www.caranddriver.com/columns/a-look-behind-the-tire-hysteria

Are you trying to predict a point of collapse or trying to decide what is safe? A conservative approach, at least for any possible failure of the ceiling itself, would be to assume a simply supported beam. As Bender mentioned where the steel is incorporated is important, and also whether it is prestressed. I do this all the time for steel, other alloys or composites (usually grp/frp), sometimes wood, but rarely for concrete. I would expect picking safety factors would take a bit of experience, similar in some respects to composites (which it actually is)

I think we can trust swansont to air on the safe side.

I have to admit that made me laugh