Re: [Phys-L] no spin decay

[bernard cleyet <bernard@cleyet.org>]

> On 2017/Sep/17, at 13:38, David Bowman <David_Bowman@georgetowncollege.edu> wrote:
>
>
> OTTH, if one doesn't want to test for or model any particular underlying decay mechanism/model, but just wants mathematically represent how the decay happens one could simply fit the decay curve directly using an appropriately parameterized fitting function. 


That is what I've done.  It gives the relative proportion of the several “models”.  


An apposite discussion:  

 http://www.cleyet.org/Pendula,%20Horological%20and%20Otherwise/HSN/HSN%20published%20articles/PDFs/Q%20of%20a%20%22grand%20mother%22%20clock's%20pendulum.pdf  


bc,  amateur horologist


p.s. very nota bene:   My supposition that the end of the decay is characterized by da Vinci (Coulomb) dissipation is not correct.   It an artifact of the data collection [the flag (interrupter) becomes a significant proportion of the amplitude.]  David Drumheller has described a correction which requires beat (not period) data and assumes sinusoidality (of course at small amplitudes rather true)  

A = b/[2sinPi (  t / 2T ) ]  Where t is the beat of the current sample and T is the beat before and after the current sample.  The position of the photogate must be at BDC.  If not the correction algorithm is complicated.   {Horological Science Newsletter 2012-4, Sept. 2012}