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  • Author or Editor: Maria Santarelli x
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Abstract  

Use was made of thermal and other techniques to characterise three native asphalt samples. The purpose was to support archaeological investigations reconstructing their thermal history and composition. The first sample (from a Roman quarry in central Italy) proved to have 37% impurities, no sign of oxidation or degradation and to have never been heated to above 100°C. The second sample (from a Roman ship sunk south of France) was pure, but partially oxidised, with a saturated fraction in its structure. Analyses of the latter sample, obtained from the eye of a Thracian bronze head, revealed that the asphalt had been heated to over 100°C and then mixed with natural wax.

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Abstract  

Modulated DSC has been applied to the study of methane, ethane and propane hydrates at different hydrate and ice concentrations. The reversing component of the TMDSC curves, makes it possible to characterize such hydrates. Methane and ethane hydrates show the melting-decomposition peak at a temperatures higher than the ice contained in the sample, while propane hydrate melts and decomposes at lower temperature than the ice present in the sample. The hydrate peaks tend to disappear if the hydrate is stored at atmospheric pressure. Guest size and cavity occupation fix the heat of dissociation and stability of the hydrates, as confirmed by parallel tests on tetrahydrofurane hydrates.

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