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Neat stuff wot I have found

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tetsabb
1355983.  Sat Aug 15, 2020 6:00 am Reply with quote

Jenny wrote:
Another fascinating thing - a virtual model of the Antikythera mechanism, showing how it worked.

https://bigthink.com/robby-berman/an-ancient-device-too-advanced-to-be-real-gives-up-its-secrets-at-last


Should there not be a Pro-Kythera device, too?
😉

 
CB27
1355998.  Sat Aug 15, 2020 9:25 am Reply with quote

Not since they lost 48-52

 
Efros
1356330.  Wed Aug 19, 2020 3:37 am Reply with quote



Osprey Vortices.

 
Celebaelin
1356365.  Wed Aug 19, 2020 9:59 am Reply with quote

Water vapour condensing under pressure and then re-evaporating?

 
PDR
1356372.  Wed Aug 19, 2020 10:17 am Reply with quote

The opposite.

The pressure difference above and below the blade causes a powerful vortex to form at the tip of the blade. This vortex has a high rotational velocity which results in a pressure (and thus temperature) drop in the centre which is sufficient to drop the saturation humidity of the air. When humidity is high this will cause the relative humidity to get over 100%, so water condenses out as a cloud of droplets. As soon as the vortex expands the pressure/temperature equalises with the surrounding air, reducing the RH and allowing the water to evaporate again.

It's the same as an aircraft con-trail (although at very high cruising altitudes the water will condense into glistening ice rather than re-evaporating due to the low ambient air temps, and of course the osprey rotor vortices won't be injected with mind-controlling drugs like those of airliners.

PDR

 
Celebaelin
1356387.  Wed Aug 19, 2020 11:36 am Reply with quote

PDR wrote:
This vortex has a high rotational velocity which results in a pressure (and thus temperature) drop in the centre which is sufficient to drop the saturation humidity of the air.

My emphasis.

So why does the condensation occur peripherally rather than centrally?

 
PDR
1366305.  Wed Nov 25, 2020 9:42 am Reply with quote

CB27 wrote:
Not since they lost 48-52


Actually they won, as any dyed-in-the-hair attorney will confirm.

PDR

 
Efros
1372032.  Mon Jan 18, 2021 9:35 am Reply with quote

https://www.youtube.com/watch?v=EjM0RmnRiC4

from this

https://www.youtube.com/watch?v=uO4ZR1q3u4c


Snowball fight filmed by the Lumiere brothers colourized, reframed and significantly cleaned up.

 
Efros
1372350.  Wed Jan 20, 2021 2:50 pm Reply with quote

 
crissdee
1372352.  Wed Jan 20, 2021 2:56 pm Reply with quote

Amazing how consistent the curve is!

 
Efros
1372620.  Sat Jan 23, 2021 11:44 am Reply with quote

Salt crystals forming in real time, at the atomic level, actually ionic but anyway



More detail here.

 
bobwilson
1372747.  Sun Jan 24, 2021 6:05 pm Reply with quote

https://www.youtube.com/watch?v=Ezyd40kJFq0

Brings tears to the eyes - I mean, this is Pete fucking Seeger - still going, still pushing for Amnesty International - at 80 fucking 3

I mean, wow

 
Efros
1372839.  Mon Jan 25, 2021 4:55 pm Reply with quote



Shit the bed hot sauce, legit product.


Last edited by Efros on Tue Jan 26, 2021 4:10 am; edited 1 time in total

 
Awitt
1372841.  Mon Jan 25, 2021 5:31 pm Reply with quote

When I saw the first description, I thought I was reading something from an Australian summer and/or how things go with Covid fevers.

 
Efros
1373946.  Mon Feb 08, 2021 2:19 pm Reply with quote

https://i.imgur.com/msDHGyO.mp4

Lego Bridge Laying Tank

 

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