A little thing about Mass Metrology - Page 1
Forum section: electronics / general

author: SeanB
author_rank: Super Contributor
timestamp: September 30, 2012, 07:28:53 pm
content: Went and had a few masspieces verified and certificated. Nice is that they are the same as last time, which is good.Top is the small masspieces I have, and the certificate I got for them. I only wanted the 2 highest mass ones done, but all were done......... I now can be sure that I can accurately verify a 5 milligram massmeter to 3 decimal places......, or to the microgram.Some of the massmeters I have are so sensitive just breathing will show up, thankfully only one ( not used) is so sensitive that it reacts to body heat.The lower 5 are a few pictures of the calibration facility I used, with the small massmeter and the small masspieces they use to do the mid range testing. The mobile lifting frame is not an optional extra, the big cylinders are 1ton masspieces, and they are known to 10g. The biggest masspieces are not there, but sit on a rail siding in a shed, they are rail cars used to verify inline massbridges for the railways. 300 Tons.........There is a lot of shelving as well, containing confiscated goods that do not meet spec, awaiting the final trip to the crusher. Just because they burst into flame and explode................

author: Unknown
author_rank: Unknown
timestamp: September 30, 2012, 08:37:33 pm
content: Thanks for posting something a little different from the usual metrology stuff we see around here. A nice change of pace of the regular voltage and resistance standards.Quote from: SeanB on September 30, 2012, 07:28:53 pmHow much drift would you expect? I would assume they are handled carefully to prevent contamination or damage and are made of a substance that's not sensitive to corrosion. I guess changes in humidity would introduce uncertainty.Quote from: SeanB on September 30, 2012, 07:28:53 pmHow would the mass change with temperature? Evaporation/condensation of moisture?

author: IanB
author_rank: Super Contributor
timestamp: September 30, 2012, 08:49:51 pm
content: Quote from: alm on September 30, 2012, 08:37:33 pmI think he was saying the instrument (mass meter) would respond to the influence of body heat leading to uncertainty in the measurement.

author: saturation
author_rank: Super Contributor
timestamp: September 30, 2012, 10:28:58 pm
content: Most interesting, thanks for posting. What goods are these, mass meters or the mass references? I can understand electronic mass meters being off, but quality references must take a long time or abuse to need to be discarded.Quote from: SeanB on September 30, 2012, 07:28:53 pm

author: robrenz
author_rank: Super Contributor
timestamp: September 30, 2012, 11:51:19 pm
content: Thanks for posting. I find all areas of metrology very interesting.

author: SeanB
author_rank: Super Contributor
timestamp: October 01, 2012, 04:43:26 am
content: Drift depends on handling and storage, as the masspieces are brass and steel, so they oxidise or lose mass from rubbing if improperly handled.The shelves are full of cookers, lead/mercury containing face creams and other such stuff, all found to be substandard.As to massmeters responding to body heat, some are sensitive enough to measure down to the nanogram level, and are sensitive enough to actually detect the impact of radiation on them.