The Mutation Analysis of Ultrasonic Acoustic Emission in Cavitation

Cavitation and embolization of plants accompanied by conduit vibration due to intermolecular adhesion of water or the adhesion of the conduit wall are signs of water stress. Ultrasonic acoustic emission (UAEs) was used to detect plant air pockets and embolic events transmitted by vibration. The UAEs could be detected in ultrasonic frequency between 100K Hz and 1 MHz. In general, the spatial location of UAEs sources for the influence of signal spatial distribution are greater than the UAEs signal wave shapes to the time. Using the electro-acoustic similarity theory, UAEs can be seen as the step voltage sources, the medium as the load, the water column rupture model (UAEs mutation model) in the plant conduit can be established by the analog circuit method. Without considering the change of plant stems medium density and ultrasonic velocity, the ultrasonic energy is proportional to square of the ultrasonic pressure. According to plant water stress relationships between ultrasonic energy release and ultrasonic energy, the UAEs ring counts or signal strength can be used to indicate the range and extent of plant conduits embolism, which can establish the model of UAEs and physiology by statistical laws. Studies have shown that the UAEs waves transmit in the plant fiber, signal attenuation in the fiber is a function of cell tissue hardness, and the approximate attenuation values are 1 dB/cm, 10 dB/cm and 20 dB/cm in hardwood, softwood and herbaceous plants, respectively.