The laser-pulse method is a well-established nonsteady-state measurement technique for measuring the thermal diffusivity, a, of solid homogeneous isotropic opaque materials. BNM-LNE has developed its own bench based on the principle of this method in which the thermal diffusivity is identified according to the "partial time moments method." Uncertainties of thermal diffusivity by means of this method have been calculated according to the ISO/BIPM "Guide to the Expression of Uncertainty in Measurement." Results are presented for several cases (Armco iron, Pyroceram 9606) in the temperature range from 20 to 800 • C. The relative expanded (k = 2) uncertainty of the thermal diffusivity determination is estimated to be from ±3 to ±5%, depending on the material and the temperature.

LNE, NPL, and PTB decided in 2005 to join their research efforts in the framework of Euromet Project 857 with the aim of reducing the calibration uncertainty of noble metal and other high-temperature thermocouples by at least a factor of two. This ambitious target will be met through the development and implementation of robust high-temperature fixed points based on metal-carbon eutectic technology. The Euromet project is structured around five work packages and ensures good and efficient cooperation between the partners to meet the objectives within the project timeframe of four years. Furthermore, a formal cooperative research agreement has been established with the National Metrology Institute of Japan (NMIJ) to demonstrate, on a worldwide basis, that this new method is a significant improvement over current calibration methods. In summary, the project consists of (a) the development of sets of cells at the cobalt-carbon eutectic point (1,324 • C) and palladium-carbon eutectic point (1,492 • C) and (b) the construction of platinum/palladium (Pt/Pd) thermocouples carefully stabilized for use to these temperatures. Supplementary research to be undertaken as part of this project is the improvement of fixed-point construction and realization capabilities through high-temperature furnaces with low thermal gradients. This paper describes the European project and gives an overview of current progress.

A new reference calorimeter has been developed under a European research project and set-up by Physikalisch-Technische Bundesanstalt (PTB) in Germany. The objective of the project is to measure the superior calorific value (SCV) of methane and other pure gases with a measurement uncertainty of less than 0.05 %. This paper presents the measurement results obtained for methane. Nine repeatability measurements were made. The molar SCV obtained when the measurements were averaged is 890.578 kJ·mol −1 . This value agrees very accurately with the value of 890.63 kJ·mol −1 specified by ISO 6976 [Natural Gas-Calculation of Calorific Values, Density, Relative Density and Wobbe Index from Composition. International Standard ISO 6976, corrected and reprinted 1996-02-01]. Twice the standard deviation determined for the measurements is 0.023 % and is thus clearly lower than in previous 123 666 Int J Thermophys (2010) 31:665-679experiments. Two independent uncertainty analyses confirm that the envisaged total uncertainty of 0.05 % is achieved (95 % confidence level).

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This work investigates the effect of heating techniques on the realization of the ITS-90 fixed points above room temperature. For that purpose, LNE has constructed a new apparatus to realize the indium fixed point under adiabatic conditions using the "calorimetric" method. The adiabatic condition, in general, is established by maintaining a temperature difference between the fixed-point cell and its surroundings that is as small as possible. In this work, the indium fixed-point cell is located within thermally controlled heat shields whose walls also contain indium. Thus, the shields themselves are also indium cells. The experiments realizing the melting and freezing temperatures of indium using the calorimetric method are described. The results revealed the existence of thermal effects in the realization of the indium fixed-point cell by the conventional "continuous heat flux" method. The advantages of the "cell-withincell" technique are presented.