Posted for "Jim Nordin" <panelmaker@earthlink.net>:

 Bob,
 
 Thanks for the information but frankly you're over my head. I'm just a
 physical chemist with little metallurgical training and even less in the
 intricacies of these engines. I'm simply pointing out, we as owners and
 users of expensive machines, should rely on empirically derived decisions to
 save our hardware rather than theory or OWTs.
 
 I would never recommend coming to idle at 20,000' (or any very cold
 altitude) as a reasonable method of loosing altitude -- and I think all on
 the list would agree. I think all of us know gradual and calculated changes
 in our aircraft operations are preferred in all our activities excepting
 emergencies.
 
 Clearly your knowledge and experience of this subject is above my
 understanding. Thanks for sharing it with us.
 
 Jim