15 Международная конференция по свойствам воды и водяного пара.

Wolfgang Wagner.
From the Beginning to this Day - My First Naive Ideas and the Research Results Achieved.

In the period from 1975 to 2006, the Chair of Thermodynamics at the Ruhr-University Bochum was working in the field of the calculation and experimental determination of thermodynamic properties of pure fluid substances and mixtures. The research projects have covered the fields of equations of state, very accurate density measurements with new types of densimeters, and the critical region of pure fluids. This article gives a survey of these research activities emphasizing the close interaction between the development of equations of state and very accurate density measurements (- data). Moreover, a statement on the critical exponents is given, and the development of a new equation of state for natural gases and other mixtures is described.

Since the establishment of the International Temperature Scale of 1990 (ITS-90), much progress has been made in the development of radiometers and blackbody sources. Cryogenic electrical-substitution radiometry is widely used in detector and radiometer calibrations, and stable, high-temperature metal–carbon eutectic blackbodies are under development. Radiation thermometers can be calibrated for absolute radiance responsivity, and blackbody temperatures determined from the amount of optical power without the use of any fixed points to directly measure thermodynamic temperatures. These thermodynamic temperatures can be measured with lower final uncertainties than the ITS-90 derived temperatures, and these developments will directly impact future international temperature scales.