Calibration services of five countries from the Sistema Interamericano de Metrología (SIM) region are compared through measurements of surface roughness and step height standards. A surface roughness standard with a nominal roughness average (Ra) value of 0.2 µm, a surface roughness standard with a nominal Ra value of 3 µm and a nominal spatial wavelength of 99 µm, and three step height standards with nominal values of 2.55 µm, 0.38 µm and 0.03 µm are compared. Special attention is paid to the influence of the long wavelength cutoff ratio of the measurements. Results are reported for Ra, maximum height of profile Rz, mean width of profile elements RSm, and step height d, depending on the sample measured. The initial reported results show that the laboratories agree on all of the measurements within their stated and published uncertainties. Observations are then discussed about the definition of Rz, the effect of instrument noise on Rz, the different step height parameters d and Pt, differences between the laboratories in reporting Type A statistical uncertainties, the method for calculating the uncertainty of the reference value, and the importance of accounting for correlations between the reference value and individual lab values when calculating the degrees of equivalence. After corrections and reanalysis the laboratories still agree well considering their stated uncertainties.

Mass calibration is an important activity for national metrology institutes because of the number of measurements on scientific, industrial and legal activities that have traceability to the national mass standards of each country.In order to evaluate the stated uncertainty and degree of equivalence between CENAM-Mexico and INTI-Argentina on mass calibration a bilateral comparison was agreed between the two laboratories. An additional objective of this bilateral comparison was to demonstrate capabilities in mass calibration by subdivision methods, which are widely used for calibration of weights of the highest accuracy classes.In order to reach such objectives, two weights of stainless steel were measured in both laboratories from April to June 2005. For the measurements both laboratories used their own facilities, equipment, mass standards and procedures. The measurements made in each laboratory are traceable to the prototype of CENAM and to the national mass standard of INTI, respectively.Results reported by both participants are consistent within the reported uncertainties, and the largest normalized error (calculated for 1 kg) is 0.89.Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by SIM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

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A regional supplementary comparison for the volume of liquid at 50 mL was conducted during October 2009 to June 2010 between the SIM members CENAM, INTI, INMETRO, INDECOPI and INTN. The transfer standard consisted of two 50 mL glass pycnometers, of the Gay Lussac type. CENAM acted as the pilot, collected the measurement results, analyzed the data and produced the comparison report.The median of all participants' results was used to calculate the regional comparison reference value because the result for one of the two pycnometers in one laboratory failed the chi-squared test at the 0.05 probability level. The measurements reported by the participants show an excellent overlap in four out of the five NMIs (−34×10−6 < Di < 29×10−6). The degree of equivalence obtained herein will be taken into account for the preparation of calibration and measurement capabilities claims from the participants.Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the SIM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

A set of statistical tools is proposed for the optimization of an alternating current-direct current voltage or current transfer step-up scheme. These tools are used to remove standards with level dependence and instabilities and to discard unusual measurements with the aim of minimizing the uncertainties. The method was applied to the new Instituto Nacional de Tecnologia Industrial current step-up.