To provide a deeper insight about the damping effects produced by the viscoelasticity of non- Newtonian fluids during density measurements with oscillation-type density meters, and about how reference laboratories overcome these effects, an international comparison was performed, within the scope of the EMPIR Project 17RPT02 rhoLiq. The results of the comparison evidenced the possibility to measure density of viscoelastic samples by means of oscillation-type density meters with an uncertainty between 0.10 kg·m<sup>-3</sup> and 0.25 kg·m<sup>-3</sup>. However, these instruments may be able to reach lower uncertainties if compared with higher precision density measurement methods such as hydrostatic weighing.
The project 19RPT02 “Improvement of the realisation of the mass scale” (EMPIR Call 2019 – Energy, Environment, Normative and Research Potential) has just started.<br />Its aim is to improve the quality of one of the most important tasks in mass metrology, the realisation of the mass scale. After the new definition of the kilogram this technique is getting more important.
It was decided at the EURAMET TC-M meeting in Torino in 2006 to realize a comparison in gauge and absolute pressure up to 200 kPa as it would allow establishing a link to the CCM.P-K6 and CCM.P-K2 comparisons. This project from the beginning interested a lot of laboratories with participants, 22 of which have submitted results. The circulation of the transfer standard began on July 2009 and lasted until January 2012. No major problem occurred during the transport.The mesurand of the comparison is the effective area of a piston-cylinder determined in gauge and absolute pressure from 25 kPa to 200 kPa with pressure steps of 25 kPa. The transfer standard is a gas lubricated tungsten carbide piston-cylinder with an effective area of ~9.8 cm 2 , fabricated by DH Instruments and compatible with a PG-7601 pressure balance. Some participants used their own pressure balance while a pressure balance with a reference vacuum sensor has been circulated for the participants not equipped with this system.One participant (SMU, Slovakia) has never provided the measurement results and another participant (FORCE Technology, Denmark) submitted a revised set of measurement results after the pilot laboratory mentioned that the equivalence was not met.After the determination of the reference value, all the 22 participants who delivered the results in gauge pressure demonstrated equivalence respective to the reference value on most of the range. In absolute pressure the equivalence is demonstrated, for all nominal pressures, by all 17 participants who submitted results.
The eye-tonometers are the important medical devices with measuring function which are necessary for the screenings of the intraocular hypertension (a serious risk factor for the glaucoma). However, it is not an easy task to ensure their correct metrological traceability. There is needed not only a wide range of various equipment but also the relevant know-how. Hence, a training centre for this quantity was established at the Czech Metrology Institute (CMI) within the framework of a smart specialisation concept for the intraocular pressure (IOP) metrology. The paper briefly outlines its history, scope, methodologies and future development plans
Many laboratories within Euramet started a calibration service in medium and high vacuum recently and did not have the opportunity to take part to a comparison before. In order to assess the uncertainty budget and the quality of the measurement of these laboratories, an intercomparison, Euramet 1040 registered as Euramet.M.P-S7, from 0.1 mPa to 0.9 Pa has been organised. The participants are the CMI (Czech republic), EIM (Greece), IMT (Slovenia), INRIM (Italy), IMBIH (Bosnia Herzegovinia) and MIKES (Finland) while METAS (Switzerland) is pilot laboratory. Three laboratories (INRIM, CMI and METAS) involved in this work have a primary definition of the pressure. Two spinning rotor gauges and a control electronic are used as transfer standard. The circulation of the transfer standard is organised as a succession of loops with a measurement by the pilot between each participant. A reference value has been determined based on a weighted mean of the results of the primary laboratories. All the participants have demonstrated their equivalence in the definition of the pressure. This comparison has been used as pilot comparison for the CCM.P-K14 project which covers the same scope with similar transfer standards.
Main text
In order to demonstrate the equivalence in calibration of 500 kg mass standard, a supplementary comparison has been carried out by 20 members of EURAMET. The overall result shows a good consistency among the participants.
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 https://www.bipm.org/kcdb/.
The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
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