Hi The primary standard of mass today is simply an arbitrary lump of metal sitting in Paris. There's no atom counting involved. There also is a Watt Balance project trying another approach to rectifying the issue. The only one that seems to be Time Nutty is the quartz resonator proposal.
Bob -----Original Message----- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bruce Griffiths Sent: Tuesday, January 22, 2013 3:30 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] One Kg Quartz Resonator But can the number and type of atoms in such a standard be counted? Otherwise its not a primary standard. Bruce Bob Camp wrote: > Hi > > The objective of the Avogadro Project seems to be getting to an accuracy of > 0.03 ppm from a current level of ~ 10X that. The suggestion in the paper is > that a quartz resonator could be monitored for change to a much tighter > level than that. > > Bob > > -----Original Message----- > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On > Behalf Of Bruce Griffiths > Sent: Tuesday, January 22, 2013 2:39 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] One Kg Quartz Resonator > > Poul-Henning Kamp wrote: > >> Content-Type: text/plain; charset=ISO-8859-1 >> -------- >> In message<7cc93b1acc5743a3b5536dbf798b7...@vectron.com>, "Bob Camp" >> > writes: > >> >> >>> There's a paper in the February IEEE UFFC transactions proposing that the >>> > SI > >>> standard of mass be replaced with a 1 KG quartz resonator. >>> >>> >> Has anybody ever studied if mono-isotopic quartz in the first place ? >> >> I pressume that would be a requirement in order to link it to the >> atomic weight unit ? >> >> >> >> > The current intention is to accurately measure Silicon 28 single crystal > spheres and use the result to refine the value for Avogadros number and > thus allow a redefinition of the kilogram using Avogadros number and the > mass of an atom: > > http://www.ptb.de/en/aktuelles/archiv/presseinfos/pi2011/pitext/pi110127.htm > l > > Essentially one would then measure mass of such standards by counting atoms. > > Bruce > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.