Re: [Phys-L] Q for band width is not valid. Was: Re: finding Q from band width?

[brian whatcott <betwys1@sbcglobal.net>]

On 10/21/2013 3:49 PM, Bernard Cleyet wrote [in small part]:
> some better clocks use silica pendula in addition to reduced thermal 
> sensitivity.
/snip/
> bc maths declined, so won't even try a trial solution.

I recall that a fused silica rod may be purchased at inconsiderable cost 
from a US source.
These shiny glass surfaces have a quasi-hygroscopic property which has 
apparently defeated some precise measurements of  small weights: still, 
the wooden pendulum has a thermal coefficient which may be quite low, 
but is also rather hygroscopic.     I recall some suggestions that 
miniature ball races cleaned of all lubricant can serve as relatively 
low-loss pivots, eliminating the flexure's variation in effective 
pendular length with amplitude and mass.

Brian Whatcott     Altus OK