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[摘要]：Measurements of density, speed of sound, and viscosity have been carried out on liquid certified reference materials for biofuels as a function of temperature at ambient pressure. The samples included anhydrous and hydrated bioethanol and two biodiesel fuels from different feedstocks, soy and animal fat. The ethanol samples were measured from a maximum temperature of 60 to 5 degrees C (speed of sound) and to -10 degrees C (density and viscosity), respectively. The biodiesel samples were characterized from 100 degrees C (density and viscosity) and from 70 degrees C (speed of sound) to 10 degrees C (animal fat-based) and 5 degrees C (soy-based). Densities were measured with two vibrating-tube instruments of different accuracy. The speeds of sound were measured with a propagation-time method in an acoustic cell that was combined with one of the densimeters. Viscosities were measured with an open gravitational capillary viscometer and with a rotating concentric cylinder viscometer, according to Stabinger. The measurement results are reported with detailed uncertainty analyses. |
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