How does ultrasound influence the thermal stability of wood?

How does ultrasound contribute to the migration of extractives inside Ailanthus altissima wood?

“…For example, Meullemiestre [30] found a 40 % increase in polyphenol content derived from marine pine sawdust compared to traditional extraction methods under the condition of ultrasound intensity of 0.67 W/cm 2 , processing temperature of 40 °C, and ultrasonic time of 43 min. Our previous research also revealed that both the organic and hot water extractives decreased under ultrasonic treatment with a frequency of 25 kHz and a power of 320 W [31] . Ultrasound also had an impact on the physicochemical properties of the wood.…”

“…As commonly acknowledged, ultrasound induces both mechanical effect and cavitation effect, generating in microjets with instantaneous high temperature and high pressure. Consequently, ultrasonic treatment has been shown to influence the distribution of chemical components within the cell wall of wood [44] , facilitate the migration of extractives, and decrease their relative content [31] . Based on this experiment, the migration model of extractives inside Ailanthus altissima wood during ultrasonic treatment was illustrated in Fig.…”