EURAMET.M.D-S2 Final Report Final report

Transcription

1 Fnal report on ERAMET blateral comparson on volume of mass standards Project number: 1356 (ERAMET.M.D-S2) Volume of mass standards of 10g, 20 g, 200 g, 1 kg Zoltan Zelenka 1 ; Stuart Davdson 2 ; Cslla Vámossy 3, 1 Introducton Ths report descrbes a European regonal blateral comparson of volume determnaton of stanless steel standards of 10 g, 20 g, and 200 g and 1 kg carred out under the auspces of ERAMET (project 1356). It s regstered as ERAMET.M.D-S2. The objectves of the present comparson were to check the measurement capabltes of the partcpants n the feld of volume measurements of weghts and provde a bass for the calbraton measurement capabltes (CMC). BEV (Austra) was the plot laboratory and the provder of the transfer standards. MKEH was the other partcpant n the blateral comparson and NPL collected the measurement data ensurng the mpartalty. The tme schedule Ths comparson was agreed n February 2015 and was planned to complete n about 6 months. The project was slghtly delayed. The fnal schedule s detaled n table 1. Table 1: Tme schedule of the comparson Tme Acton February 2015 Fnalsaton of the techncal protocol March 2015 Selecton of the standards and mass measurements n BEV Aprl - July 2015 Measurements n MKEH and BEV August - September 2015 Draft A October - November 2015 Draft B December 2015 Fnal Draft 1 Bundesamt für Ech und Vermessungswesen, Arltgasse 35, 1160 Wen 2 Natonal Physcal Laboratory, Hampton Road, Teddngton, Mddlesex, TW11 0LW 3 Magyar Kereskedelm Engedélyezés Hvatal, 1124 Budapest, Németvölgy út page 1 of 6

2 Lst of contact persons The actual partcpatng laboratores and the contact persons are lsted n table 2. Table 2: Lst of contact persons Name Zoltan Zelenka Cslla Vamossy Stuart Davdson Address Bundesamt für Ech- und Vermessungswesen Arltgasse 35 A1160 Wen, Austra MKEH 1124 Budapest, Németvölgy út Hungary Natonal Physcal Laboratory Hampton Road, Teddngton, Mddlesex, TW11 0LW Tel e-mal zoltan.zelenka@bev.gv.at vamossycs@mkeh.hu stuart.davdson@npl.co.uk 2. Descrpton of the transfer standards The transfer standards were four mass standards wth s of 10 g, 20 g, 200 g and 1 kg. The coeffcents of volumetrc thermal expanson were measured for the mass standards 200 g and 1 kg n BEV whle for 10 g and 20 g t was estmated from the lterature. The conventonal mass of the mass standard was determned only by the plot laboratory because the contrbuton to the uncertanty of volume determnaton from the mass measurement s very small. The gravty heghts were also measured n BEV. The summary of these data s n table 3 whle table 4 contans the upper s of the magnetc propertes of the mass standards measured n BEV usng susceptometer method. Table 3: Data of transfer standards provded by the plot laboratory coeffcent of volumetrc thermal expanson (ncertanty) * Conventonal mass uncertanty of the conventonal mass Ar densty durng the conventonal mass calbraton uncertanty of the ar densty Centre of gravty heghts unt 1/ C mg kg/m 3 kg/m 3 mm 10 g 20 g 200 g 45x10-6 (3x10-6 ) 45x10-6 (3x10-6 ) 45x10-6 (2x10-6 ) 10 g + 0,066 mg 0,0025 1,173 0,003 8,4 20 g 0,032 mg 0,002 1,161 0,005 10, g + 0,013 mg 0,008 1,162 0,003 21,53 49,6x kg 1 kg + 0,180 mg 0,050 1,176 0,003 36,22 (1,0x10-6 ) * The coeffcent of volumetrc thermal expanson was measured for 1 kg and 200 g and estmated for 20 g and 10g. page 2 of 6

3 Table 4: Data of magnetc propertes magnetc susceptblty χ uncertanty u χ All weghts 0,004 0,001 The polarsaton was less than 0,15 µt for the 1 kg transfer standard. For the other weghts the polarsaton was not determned, because the uncertanty due to t was consdered to be neglgble. 3. Summary of results reported by the partcpants Stablty of the transfer standards The transfer standards were measured only once n BEV because no sgnfcant drft of volume can be expected. Measured s of mass and uncertantes MKEH calbrated the volume of the mass standards from 13 th of March to 10 th of Aprl usng water as reference densty. BEV determned the volume of the mass standards from the 21 st of May to 2 nd of June 2015 aganst sold volume standard (Slcon sphere, calbrated n PTB, Germany). The results have been expressed as the reported volume and the assocated expanded uncertanty. The uncertantes have to be calculated accordng to the Gude to the Expresson of ncertanty n Measurement [1]. The results are shown n Table 5 alongsde ther correspondng expanded uncertanty. Intally the uncertantes of MKEH were overestmated due to the uncertantes beng calculated usng the standard devaton nstead of the standard devaton of the mean. The orgnal submtted uncertantes were 1 mm 2 for 1 kg; 5 mm 2 for 200 g; 1,3 mm 2 for 20 g and 0,6 mm 2 for 10 g. page 3 of 6

4 Table 5: Reported volume and the assocated expanded uncertantes BEV MKEH Volume uncertanty Volume uncertanty cm 3 mm 3 cm 3 mm 3 1 kg 125,4961 0,44 125, , g 25,4372 0,2 25, ,67 20 g 2, ,12 2, ,61 10g 1, ,1 1, ,49 The uncertanty of the 200 g standard of the MKEH measurements are relatvely hgh. The laboratory reported as a known handlng effect by the 200 g weght n the measurng setup causng hgher standard devaton. Calculaton of reference s and the assocated uncertantes The reference s are the weghted mean s of the determned volumes of the partcpants. The uncertanty of the reference has been calculated wth the followng assumptons: The correlatons assocated wth measured s provded by the partcpants are neglgble, because of the dfferent standards and methods used n the comparson. ncertanty due to the nstablty of the travellng standards s neglgble. X ref = ( W x ) ; W ref 1 1 ( 95%) = ; wth W = 2 W ( where: - X ref s the reference of a mass standard n ths comparson - ref s the expanded uncertanty of the reference - x s the volume determned by the laboratory. - (x ) s the expanded uncertanty of the determned volume (x ). - W s the weghng factor of the determned volume (x ) X) page 4 of 6

5 Table 6: Reference s and the assocated expanded uncertantes Reference reference cm 3 mm 3 1 kg 125, , g 25, ,20 20 g 2, ,12 10g 1, ,10 4 Degree of equvalence, mass dfference and uncertanty between the measured s of BEV and the reference s The Degree of equvalence, D, s the dfference between the obtaned by the laboratory and the reference whle the assocated uncertanty s takng nto account the correlaton between the laboratory result and the reference calculated as: D = 2 (x ref 2 ) (x ) The degree of equvalence s defned [2] by two quanttes: frst the dfference between the obtaned by the laboratory and the reference and second the uncertanty of ths dfference at a level of 95 % confdence. The degree of equvalence can be found n table 7. Table 7: Degree of equvalence of the partcpatng laboratores wth the E n s D BEV D BEV E n D MKEH D MKEH mm 3 mm 3 - mm 3 mm 3 - E n 1 kg -0,18 0,20-0,90 0,68 0,75 0, g -0,017 0,024-0,73 1,2 1,7 0,73 20 g -0,004 0,023-0,19 0,12 0,60 0,19 10g 0,003 0,020 0,17-0,08 0,48-0,17 6. Dscusson For acceptable measurement results n a comparson the condton D < (D ) should be fulflled. Ths condton s fulflled n case of all the volume determnaton of the mass standards (see table 7).Therefore the objectves of the comparson (to check the measurement capabltes n the feld of volume determnaton of the mass standards to demonstrate the metrologcal equvalence of the partcpatng laboratores and to check and support the calbraton measurement capabltes) are acheved. page 5 of 6

6 8 References [1] Gude to the Expresson of ncertanty n Measurement, BIPM, IEC, IFCC, ISO, IPAC, IPAP, OIML, 1993 [2] Mutual recognton of natonal measurement standards and of calbraton and measurement certfcates ssued by natonal metrology nsttutes, BIPM, Pars, 14 October 1999 page 6 of 6