title: The kelvin redefinition and its mise en pratique.
abstract: In 2018, it is expected that there will be a major revision of the International System of Units (SI) which will result in all of the seven base units being defined by fixing the values of certain atomic or fundamental constants. As part of this revision, the kelvin, unit of thermodynamic temperature, will be redefined by assigning a value to the Boltzmann constant k. This explicit-constant definition will define the kelvin in terms of the SI derived unit of energy, the joule. It is sufficiently wide to encompass any form of thermometry. The planned redefinition has motivated the creation of an extended mise en pratique ('practical realization') of the definition of the kelvin (MeP-K), which describes how the new definition can be put into practice. The MeP-K incorporates both of the defined International Temperature Scales (ITS-90 and PLTS-2000) in current use and approved primary-thermometry methods for determining thermodynamic temperature values. The MeP-K is a guide that provides or makes reference to the information needed to perform measurements of temperature in accord with the SI at the highest level. In this article, the background and the content of the extended second version of the MeP-K are presented.
authors.affiliation: Department 7.4 Temperature, Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany bernd.fellmuth@ptb.de.
authors.forename: B
authors.initials: B
authors.lastname: Fellmuth
authors.affiliation: Department 7.4 Temperature, Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Fischer
authors.affiliation: Engineering Measurement, National Physical Laboratory (NPL), Teddington, Middlesex, UK.
authors.forename: G
authors.initials: G
authors.lastname: Machin
authors.affiliation: Bureau International des Poids et Mesures (BIPM), Sèvres, France.
authors.forename: S
authors.initials: S
authors.lastname: Picard
authors.affiliation: Istituto Nazionale di Ricerca Metrologica (INRIM), Turin, Italy.
authors.forename: P P M
authors.initials: PP
authors.lastname: Steur
authors.affiliation: National Metrology Institute of Japan (NMIJ), AIST, Ibaraki, Japan.
authors.forename: O
authors.initials: O
authors.lastname: Tamura
authors.affiliation: Measurement Standards Laboratory of New Zealand (MSL), Lower Hutt, New Zealand.
authors.forename: D R
authors.initials: DR
authors.lastname: White
authors.affiliation: National Institute of Standards and Technology (NIST), Gaithersburg, MD, USA.
authors.forename: H
authors.initials: H
authors.lastname: Yoon
keywords: International System of Units; kelvin; mise en pratique; temperature; temperature scale; thermodynamic temperature