The Meyer hardness of wood pellets was also measured by the MTI
50 K press machine. TheMeyer hardness (HM)was applied to characterize
the durability of alfalfa cubes with a flat surface [14]. Penget al.modified
the Meyer hardness forwood pellets that laid horizontally on a flat
surface [9].With a 6.35 mmhemispherical probe on theMTI 50 K press
machine verticallymoving downward at a speed of 1 mm/min, both the
force and displacement of the probe were recorded by the MTI 50 K
press machine control system. The equation for calculating HM for a
hemispherical probe and a cylindrical pellet was given below