talkFestool  

Go Back   talkFestool > Social Club (Off Topic) > Woodworkers Cafe

Woodworkers Cafe General Chat

Reply
 
LinkBack Thread Tools Display Modes
  #21 (permalink)  
Old 09-02-2008, 07:36 PM
joraft's Avatar
Administrator
 
Join Date: Jul 2008
Location: San Fernando Valley (SoCal)
Posts: 6,575
Default Re: The Alvin submarine and effects of pressure

Quote:
Originally Posted by Poto View Post

... That meant that there was $35,000 less in each of their grants to do other things with. Ultimately, though, the American taxpayer paid.

Even though they're not working with their own money, I guess there's plenty of incentive to avoid such losses. So much work that may not get done because of one stupid and avoidable mistake.
__________________
John
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
  #22 (permalink)  
Old 09-02-2008, 08:07 PM
Poto's Avatar
Super Moderator
 
Join Date: Jul 2008
Location: San Diego, CA
Posts: 8,999
Default Re: The Alvin submarine and effects of pressure

You're right about that, John. I was pretty miffed that the mistake happened - you have to be super careful at sea, because bad things can happen very suddenly.

Still, though it was an expensive lesson, you can bet that those grad students won't make that mistake again!

And the crushed pressure case makes a great teaching tool!
__________________
I don't have as many Festools as Fred. Or Marcou's, or Brese's, or Lie-Nielsen's, or Lee Valley's, or Blue Spruce's, or Harold and Saxon's, or...
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
  #23 (permalink)  
Old 09-02-2008, 08:31 PM
BobSwenson's Avatar
Member
 
Join Date: Aug 2008
Location: The hub of Morris County, NJ
Posts: 580
Default Re: The Alvin submarine and effects of pressure

Poto
Aside from crushing instruments and shrinking cups there must be something
that the pressure can be used for, after all it's almost free. How much pressure does it take to squeeze carbon into a diamond. Go to sea with a little soot and come home with the loot. Yes, I know it won't work, but it could make a great story. You could flash one in class and con your students, Count them in, hot to sail. Bah, humbug, back to the drawing board.

Shrunken heads used to be popular.

Barnacle Bob

Your lucky your wife is so clever or you would still be b-s-en at lunch with your buddies.
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
  #24 (permalink)  
Old 09-02-2008, 10:13 PM
Poto's Avatar
Super Moderator
 
Join Date: Jul 2008
Location: San Diego, CA
Posts: 8,999
Default Re: The Alvin submarine and effects of pressure

Dear Barnacle;

I had a student last year who came up with this brilliant idea to stop the carbon dioxide accumulation in the atmosphere:
Keep making Americans fatter (they contain more organic carbon). When they die, crush them into diamonds. The carbon's locked up forever!

Brilliant!

Actually the idea of using gradients in the ocean to do something useful is an old one. I've not come across much that utilizes the pressure, but there are some clever devices that use the temperature and salt gradients (it's colder and saltier in the deep water). You can make a vertical pump just using the thermal gradient in the ocean.

We do something pretty clever, too: we have an instrument that profiles through the ocean using only the energy of the surface waves to run it. Picture a wire suspended from a float that's bobbing up and down with the waves. Then picture a cam mechanism (like an ascender in climbing) on the wire. Every time the float heaves up, the wire passes through the cam. Every time the wave goes down, the cam clamps on the wire. Eventually the cam will walk its way down the wire. At the bottom we put a little trip mechanism that releases the cam, and the cam (plus all the attached instrument) float up the wire to the surface. Then it all repeats. We can get profiles over 25 meters of wire about every 3 minutes, for weeks at a time. With no batteries! Pretty cool.
__________________
I don't have as many Festools as Fred. Or Marcou's, or Brese's, or Lie-Nielsen's, or Lee Valley's, or Blue Spruce's, or Harold and Saxon's, or...
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
  #25 (permalink)  
Old 09-02-2008, 11:16 PM
BobSwenson's Avatar
Member
 
Join Date: Aug 2008
Location: The hub of Morris County, NJ
Posts: 580
Default Re: The Alvin submarine and effects of pressure

Very clever, but what about the shrunken heads.

Barnacle Bob

I once suggested to a friend who owns a good hunk of Curacao that he could cool his hotel by sinking an insulated pipe off shore and pumping the cold water up to do the cooling. It's deep there. He just smiled at me, a lot of people seem do that. :p

All this water talk reminds me of a favorite cartoon

A deserted island with only one palm tree and an upright piano and two penguins. one penguin was sitting at the piano and the other was standing next to him dressed up with a top hat and a cane saying, "Lets get this right, it's our ticket our of here"
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
  #26 (permalink)  
Old 09-03-2008, 03:28 AM
MichaelKellough's Avatar
Member
 
Join Date: Jul 2008
Location: The northernmost end of the southernmost county of New York
Posts: 4,525
Default Re: The Alvin submarine and effects of pressure

Quote:
Originally Posted by Poto View Post
We had to be very careful getting the tube off the frame - it was a serious explosion hazard. If it filled with water at depth, it would be at extreme pressure when it surfaced. The explosion at depth could also have compromised the other instruments on the frame, so they all had to be handled like live bombs, and opened to relieve potential pressure buildups. Pretty scary!
Do you mean implosion? You mean when the pipe collapsed (and got wider) it could have caused adjacent things to leak and take on water at high pressure?

So how do you safely relive the pressure? Are instrument housings built with valves? Put it in an explosion proof cabinet and poke it with a long stick?
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
  #27 (permalink)  
Old 09-03-2008, 05:26 AM
Poto's Avatar
Super Moderator
 
Join Date: Jul 2008
Location: San Diego, CA
Posts: 8,999
Default Re: The Alvin submarine and effects of pressure

Oh, I constantly relive the pressure.

However, relieving the pressure is a different thing. For the most part, we don't as the pressure housings should not leak. So when the instrument comes up, it'll be back at atmospheric pressure.

If it does leak, the stick-poking method is approximately what we do.

Yes, it was an implosion - but a violent one. The pressure waves from it might have compromised the pressure housings of adjacent instruments. Turned out - in this case - it was not a problem.
__________________
I don't have as many Festools as Fred. Or Marcou's, or Brese's, or Lie-Nielsen's, or Lee Valley's, or Blue Spruce's, or Harold and Saxon's, or...
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Forum Jump


All times are GMT +1. The time now is 11:41 PM.