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Vogl J.,BAM | Kipphardt H.,BAM | Del Rocio Arvizu Torres M.,CENAM | Manzano J.V.L.,CENAM | And 15 more authors.

The measurement of the purity of zinc based on the determination of six analytes is reported. Each participant was asked to report one result for the sum of the six requested impurities and the individual results for the six impurities. The results had to be reported in mass fractions, accompanied by a full uncertainty statement including a combined standard uncertainty and an expanded uncertainty with a coverage factor applied. Each participant was free to use any suitable method(s) for the measurement of the individual impurities. In case several methods were used for one specific impurity, only one (composite) result had to be reported. For Cd and Ni a spread unusually high for IDMS was observed in parallel measurements. This spread is reflected in the relative uncertainties for Cd and Ni, which are untypically large for double IDMS analysis. For the purpose of impurity analysis in zinc, comparability of measurement results for aluminium as an analyte is possible within the target uncertainty of 30 %. Source

Kniel K.,PTB | Osawa S.,NMIJ | Chanthawong N.,NIMT | Frazer R.,NGML | And 2 more authors.

The EURAMET TC-Length decided to run an intercomparison of involute gear standards as a regional comparison with non-European involvement. From the beginning 4 NMIs and 2 competent measurement institutes with worldwide reputation for gear metrology participated at this international comparison. One of the measurement institutes (NGLM) was registered as DI during the comparison. The circulation of the standards was scheduled for 11 months starting on August 2008 with the participation of 6 NMIs. The comparison of the presented results shows that discrepancies of the values of the compared measurands of some participating NMIs in some cases were too big and below the expectations, which leaves room for further improvement. The mishandling of the standards demonstrated the needs to improve the metrological skill in some cases or to take better precautions to avoid the improper handling of the transfer standards. Source

Vogl J.,BAM | Yim Y.-H.,KRISS | Lee K.-S.,KRISS | Goenaga-Infante H.,LCG Group | And 12 more authors.

Pb, present in trace amounts in a metal matrix sample, provides a real world test of the whole chemical and instrumental procedure. By comparing the Pb isotope ratio results obtained for the bronze sample with the Pb isotope ratio results from the Pb solution, potential biases arising from the processing of the bronze sample could be effectively identified and separated from the instrumental effects arising from the measurement and data processing protocol. Each participant was free to use any method they deemed suitable for measuring the individual isotope ratios. When several methods could be used by a participant, only one composite result was to be reported. The materials were selected so that the Pb isotopic compositions of the samples were within the natural range of the Pb isotopic compositions as tabulated by IUPAC. The results showed that single collector instruments can provide accurate Pb isotope ratio results in real samples; however matrix separation must be carried out. MC-ICPMS and MC-TIMS data are consistent with each other and agree to within 0.05 %. The corresponding uncertainties can be considered as realistic uncertainties and mainly range from 0.02 % to 0.08 %. Source

Bailat C.J.,IRA | Keightley J.,NPL | Nedjadi Y.,IRA | Mo L.,Australian Nuclear Science and Technology Organization | And 21 more authors.

Detailed uncertainty reporting is imperative for proficiency tests and comparison exercises since uncertainties need to be comparable and trusted by all the participants. Even though participants do their best to follow the Guide to the Expression of Uncertainty in Measurement1, ambiguities and divergences about uncertainty evaluation remain. Consequently, to analyze the situation, the CCRI (II) Uncertainties Working Group proposed a comparison exercise (CCRI(II)-S7) about the uncertainty evaluation of a relatively simple primary activity measurement: The standardization of a 60Co source by coincidence counting. To be able to understand how various NMIs calculate coincidence counting uncertainties, our study focused on two of the dominant uncertainty components commonly quoted for 4 αβ-γ coincidence counting in the International Reference System (SIR) submissions and Key Comparison exercises: Efficiency-extrapolation and weighing. Participants from twelve different laboratories were sent the same set of measurement data from the analysis of a 60Co solution standardized at the National Physical Laboratory (NPL). Our study demonstrated the extent of the different interpretations of the uncertainty components. Some factors causing large discrepancies were isolated and are discussed. Further studies of other techniques using a similar approach would be beneficial for the metrology community. Source

Yu K.M.,Korea Research Institute of Standards and Science | Kim W.S.,Korea Research Institute of Standards and Science | Han K.S.,Korea Research Institute of Standards and Science | Hsu J.C.-M.,CMS | And 11 more authors.
CPEM Digest (Conference on Precision Electromagnetic Measurements)

A key comparison for the 10 Mo and 1 Go resistance, APMP.EM-K2, has been carried out by the Asia-Pacific Metrology Program(APMP) Regional Metrology Organization(RMO). The purpose is to establish the degree of equivalence of resistance among the national metrology institutes(NMIs) within APMP, in support of CIPM Mutual Recognition Agreement(MRA). The key comparison artifacts are three 10 Mo and three 1 Go resistance standards which was loaned from NIST and the 13 NMIs were participated in the comparison. The results will be presented at the conference. © 2014 IEEE. Source

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