Averaged Structural Units in Bituminous Coals Studied by Means of Ultrasonic Wave Velocity Measurements

摘要

The measurements of density and velocity of ultrasonic waves at frequency of 2.5 MH_z were made for coals of various rank (81.6-89.65 wt /100 of carbon). The ultrasonic suspension method was used for the ultrasonic wave velocity measurements. The simple empirical relation between ultrasonic velocity, density, and the mean atomic weight found by Pinnov for a wide range of crystalline materials was applied for coals.