2022 Update for the Differences Between Thermodynamic Temperature and ITS-90 Below 335 K

In 2011, a working group of the Consultative Committee for Thermometry published their best estimates of the differences between the thermodynamic temperature T and its approximation (T-90), the temperature according to the International Temperature Scale of 1990, ITS-90. These consensus estimates, in combination with measurements made in accordance with ITS-90, are an important alternative to primary thermometry for those requiring accurate measurements of thermodynamic temperature. Since 2011, there has been a change in the definition of the kelvin and significant improvements in primary thermometry. This paper updates the (T - T-90) estimates by combining and analyzing the data used for the 2011 estimates and data from more recent primary thermometry. The results of the analysis are presented as a 12th-order polynomial representing the updated consensus values for the differences and a sixth-order polynomial for their uncertainty estimates. (C) 2022 Author(s)

Sensors for safety and process control in hydrogen technologies

This book is about devices commonly called sensors. These devices are designed to measure physical or chemical quantities and to deliver an electrical output signal in relation to theses quantities. Sensors offer new possibilities for safety as well as process monitoring and control. They are to some extent in competition with traditional analytical instrumentation in terms of acceptance and perceived performance. Sensors have the potential to augment or even supplant traditional analytical instrumentation. These devices offer numerous advantages over so-called traditional analytical instrumentation because they are generally small sized, economical, and readily manufacturable. Sensors are compatible and integrable into electronic systems for on-site, real-time safety monitoring and process control. These features are of great importance for applications in current and emerging technologies, including hydrogen technologies, which is the topic of this book.JRC.F.2-Energy Conversion and Storage Technologie

EURAMET key comparison no. EURAMET.T-K1: realisations of the ITS-90 from 2.6 K to 24.5561 K, using rhodium-iron resistance thermometers

In the temperature range from 0.65 K to 24.5561 K, the ITS-90 is defined by specified vapour-pressure equations for 3He and 4He and interpolation equations for a constant-volume gas thermometer using 3He or 4He. The definitions are given in sections 3.1 and 3.2 of the ITS-90 text, and methods for realising the scale in this range are outlined in chapters 4 and 5 of the Guide to the Realization of the ITS-90 (formerly Supplementary Information for the ITS-90). Direct realisations of the ITS-90 by these methods require relatively sophisticated apparatus and time-consuming experiments, and consequently they are rarely carried out. The situation is acceptable in practice only because rhodium-iron resistance thermometers (RIRTs) are available that, once calibrated, are able to maintain their calibrations reliably for long periods of time. They are the practical thermometers on which realisations of the ITS-90 are most accurately maintained, disseminated and compared. The key comparison EURAMET.T-K1 is therefore a comparison of calibrated RIRTs