Author Topic: Preparation for the new SI (kg, h, e, K, V, Ohm, A..)  (Read 1886 times)

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Offline Dr. FrankTopic starter

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Preparation for the new SI (kg, h, e, K, V, Ohm, A..)
« on: October 25, 2018, 07:21:18 pm »
Everything is ready for the inauguration of the new Système International, the new SI, starting with World Metrology Day, 20th May 2019.
https://www.bipm.org/en/measurement-units/rev-si/

NIST just announced a live celebration on November 2nd;

and https://www.nist.gov/si-redefinition

The bipm, bureau international des poids et mésures, already hosts all draft documents for the new, exact definition of several constants of  nature, h, e, k, NA, which will in turn redefine the kg, the Kelvin and the Ampère, and also several derived units, like our beloved Volt and Ohm, which will get exact definitions inside SI, with zero uncertainty.
https://www.bipm.org/utils/en/pdf/si-mep/MeP-a-2018.pdf

These two electrical units lived in sin as practical units, since January 1st 1990, when the last SI definition had gone live.

From 13th to 16th November 2018, the CGPM, Conférence Générale des Poids et Mesures, https://www.bipm.org/en/cgpm-2018/ will meet in Versailles, to officially and ceremonially decide the new SI.

The draft documents already contain the finalized values for the mentioned constants of nature, like h, e as derived from many experiments, ending July 1st 2017.

These contain the defintion of the constants and units of the new SI: https://www.bipm.org/utils/en/pdf/CGPM/Convocation-2018.pdf

The mise-en-pratique, or the practical realization also has been prepared, that are the cooking books, how to bring the units to real life.
This process is of course not 'exact', as these described experiments inherently have some uncertainties.

https://www.bipm.org/en/measurement-units/rev-si/#communication

There will be a live web cast, obviously during the final decision.

Frank

PS: Attached the latest version of the mise-en-pratique for the electrical units.
« Last Edit: October 25, 2018, 08:06:07 pm by Dr. Frank »
 
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Offline branadic

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Re: Preparation for the new SI (kg, h, e, K, V, Ohm, A..)
« Reply #1 on: November 05, 2018, 06:46:16 pm »
On 2. november the link to the video showed a new date for the celebration, 5th november 16:00 if I remember right. Now the link to the video has been removed... what's going on? Did they loose their units?  :-DD

-branadic-
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Online ataradov

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Re: Preparation for the new SI (kg, h, e, K, V, Ohm, A..)
« Reply #2 on: November 05, 2018, 07:05:11 pm »
Why does the document not capitalize units derived from the names? Is it a new thing? Or was it always like that?
Alex
 

Offline dacman

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Re: Preparation for the new SI (kg, h, e, K, V, Ohm, A..)
« Reply #3 on: November 06, 2018, 12:44:05 am »
Units derived from names are capitalized when used as units but not when spelled out in a sentence.  For example, the symbol for volts is V and the symbol for ohms is \$\Omega\$ (capital omega).  There are exceptions, such as if degrees Celsius is spelled out then Celsius is capitalized (with the excuse that the first letter in degrees is not capitalized).  If I were to have 15 Ohm, then I'm technically using units, although I once had an auditor that would tell me ohm is not a unit and should not be capitalized (and I should use the actual symbol because there is a book of what official units are).

https://www.bipm.org/en/publications/si-brochure/section5-2.html
« Last Edit: November 06, 2018, 01:03:00 am by dacman »
 


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