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Old 05-01-2019, 05:45 PM
Pete VanderLaan's Avatar
Pete VanderLaan Pete VanderLaan is offline
The Old Gaffer
 
Join Date: Apr 2002
Location: Chocorua New Hampshire
Posts: 22,199
Pete VanderLaan is on a distinguished road
so, I've been asking myself a question all day and I've asked John and one of my students who took the class. It's pretty straight forward:

If we utilize the Hagy seal to make a sample indicator for differences in L.E.C., we need to recognize a few things: The seal is a sensitive sample that needs to be processed for interpretation in a really expensive tool, the Strainoptics Polarimeter, That tool cost me $2,000.00 dollars almost twenty years back. John has one and Penland borrowed one from the company for the class. It measures degrees of retardation very precisely and those variants can be converted into math differences in the expansion coefficient quite accurately.
So, John has it, I have it and I assume Penland is returning the borrowed one.

So what does the student do who wants to use hagy seals? What tool will accurately measure the retardation of light in the sample?

I taught the Hagy Seal and I taught the ring test and I taught the dilatometer. All of these tests are squishy but if one thinks about them, they should all be pointing in the same direction. Any time that mismatch tests are done, that should be the case.
What I want to know is that barring the possession of the Polarimeter, what are the other ways of using that seal? I can tell you that any sample, either Seal or ring is very far off that the sample will not survive.

I'm not trying to piss on the class at all. All accounts I've heard is that it was fabulous and John is a dear friend. I just want to know, since the Ring and pull tests were not pursued, how does one proceed? My belief is currently that the more methods, the better. No one method seals the deal.
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