The revision of the SI—the result of three decades of progress in metrology

M Stock, R Davis, E de Mirandés, MJT Milton - Metrologia, 2019 - iopscience.iop.org
On 16 November 2018 a revision of the International System of Units (the SI) was agreed by
the General Conference on Weights and Measures. The definitions of the base units were …

New measurement of the Boltzmann constant k by acoustic thermometry of helium-4 gas

L Pitre, F Sparasci, L Risegari, C Guianvarc'h… - Metrologia, 2017 - iopscience.iop.org
The SI unit of temperature will soon be redefined in terms of a fixed value of the Boltzmann
constant k derived from an ensemble of measurements worldwide. We report on a new …

Advances in thermometry

MR Moldover, WL Tew, HW Yoon - Nature Physics, 2016 - nature.com
The past 25 years have seen tremendous progress in thermometry across the moderate
temperature range of 1 K to 1,235 K. Various primary thermometers, based on a wide range …

A determination of the molar gas constant R by acoustic thermometry in helium

RM Gavioso, DM Ripa, PPM Steur, C Gaiser… - Metrologia, 2015 - iopscience.iop.org
We have determined the acoustic and microwave frequencies of a misaligned spherical
resonator maintained near the temperature of the triple point of water and filled with helium …

Improved electronic measurement of the Boltzmann constant by Johnson noise thermometry

J Qu, SP Benz, A Pollarolo, H Rogalla, WL Tew… - Metrologia, 2015 - iopscience.iop.org
The unit of thermodynamic temperature, the kelvin, will be redefined in 2018 by fixing the
value of the Boltzmann constant, k. The present CODATA recommended value of k is …

[PDF][PDF] Standard platinum resistance thermometer calibrations from the Ar TP to the Ag FP

GF Strouse - NIST Special Publication, 2008 - nvlpubs.nist.gov
The National Institute of Standards and Technology (NIST) is in charge of realizing,
maintaining, and disseminating the International Scale of 1990 (ITS-90)[1-5]. The Standard …

Volume measurements of 28Si spheres using an interferometer with a flat etalon to determine the Avogadro constant

N Kuramoto, K Fujii, K Yamazawa - Metrologia, 2011 - iopscience.iop.org
The volumes of two 1 kg silicon spheres, AVO28-S5 and AVO28-S8, fabricated from a 28 Si-
enriched crystal were measured to determine the Avogadro constant by the x-ray crystal …

[HTML][HTML] Comparison of triple point of water cells with isotopic composition between NIM and PTB

X Yan, S Rudtsch, L Bünger, P Qiu, J Zhang - Measurement: Sensors, 2024 - Elsevier
The triple point of water (TPW) is the most important defining fixed point on the International
Temperature Scale of 1990 (ITS-90), because the uncertainty in the realization of the TPW is …

Measurement of pressures up to 7 MPa applying pressure balances for dielectric-constant gas thermometry

T Zandt, W Sabuga, C Gaiser, B Fellmuth - Metrologia, 2015 - iopscience.iop.org
For the determination of the Boltzmann constant by dielectric-constant gas thermometry, the
uncertainty of pressure measurements in helium up to 7 MPa has been decreased …

Uncertainty propagation of atomic weight measurement results

J Meija, Z Mester - Metrologia, 2008 - iopscience.iop.org
General theory for uncertainty propagations of atomic weight measurement results is
presented and the impact of correlation of input variables (isotope ratios and correction …