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We measured the volume of hafnium at several pressures up to 67 GPa and at temperatures between 300 to 780 K using a resistively heated diamond anvil cell with synchrotron x-ray diffraction at the Advanced Photon Source. The measured data allows us to determine the P-V-T equation of state of hafnium. The previously described [Xia et al., Phys. Rev. B 42, 6736–6738 (1990)] phase transition from hcp (α) to simple hexagonal (ω) phase at 38 GPa at room temperature was not observed even up to 51 GPa. The ω phase was only observed at elevated temperatures. Our measurements have also improved the experimental constraint on the high P-T phase boundary between the ω phase and high pressure bcc (β) phase of hafnium. Isothermal room temperature bulk modulus and its pressure derivative for the α-phase of hafnium were measured to be B0 = 112.9 ± 0.5 GPa and B0′ = 3.29 ± 0.05, respectively. P-V-T data for the α-phase of hafnium was used to obtain a fit to a thermodynamic P-V-T equation of state based on model by Brosh et al. [CALPHAD 31, 173–185 (2007)].

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A premise was set up entailing the possibility of a synergistical combination of advantages of spectrophotometric and colorimetric matching procedures. Attempts were therefore made to test the performances of fifteen matching procedures, all based on the Kubelka-Munk theory, including two procedures utilizing the fundamental color stimulus R(FCS) of the spectral decomposition theory. Color differences CIE DeltaE(00) as well as concentration differences DeltaC(AVE) were used to theoretically rank the fifteen color matching procedures. Results showed that procedures based on R(FCS) were superior in accurately predicting colors and concentrations. Additionally, the metameric black component R(MB) of the decomposition theory also showed promise in predicting degrees of metamerism. This preliminary study, therefore, provides evidence for the premise of this investigation.