This study proposes a novel method for the rapid detection of compost moisture content. The effects of the test frequency (1 to 100 kHz), compost moisture content (5% to 35%), temperature (25 to 65 °C), and bulk density (665.6 to 874.3 kg/m³) on the dielectric properties (the dielectric constant ${\epsilon }^{\prime }$ and the loss factor ${\epsilon }^{″}$) in the compost consisting of fresh sheep and manure corn were investigated. The mechanism for the change in dielectric properties was analyzed. The feature variables of dielectric parameters (${\epsilon }^{\prime }$, ${\epsilon }^{″}$, and the combination of ${\epsilon }^{\prime }$ and ${\epsilon }^{″}$) were selected using principal component analysis (PCA), and the selected characteristic variables and the full-frequency variables were used to perform support vector machine regression (SVR) modeling. The results revealed that the increase in both temperature and bulk density in the frequency band from 1 to 100 kHz increased ${\epsilon }^{\prime }$ and ${\epsilon }^{″}$. The PCA–SVR model with both ${\epsilon }^{\prime }$ and ${\epsilon }^{″}$ combined variables achieved the best results, with a prediction set coefficient of determination of 0.9877 and a root mean square error of 0.0026. In conclusion, the method of predicting the moisture content based on the dielectric properties of compost is feasible.

A soil removal device for the root-soil complex of Gentian imitating the percussion function of a woodpecker was designed to improve the soil removal efficiency of harvesting devices for rhizome-type traditional Chinese herbal medicines. Based on the physical parameters of roots and the root-soil complex of Gentian, the structure parameters of the striking arm and the actual profile of the cam are determined according to the physical parameters when the woodpecker knocks on the tree. The key parameters that affect the working performance of the soil removal device and their suitable value ranges have been identified through the impact test and analysis of the root-soil complex of Gentian. The mass of the striking hammer, the swing angle of the striking arm, and the rotation speed of the cam were taken as the experimental factors and the soil removal rate and the energy consumption per hammer percussion were taken as the experimental indicators. The ternary quadratic orthogonal regression combination experiment was carried out using Design-Expert. The regression model of the influence factors and evaluation indicators was established through the analysis of variance. The interaction effects of the influence factors on the indicators were analyzed using the response surface method. Using multiobjective optimization method, the optimal parameter combination was obtained as that of the mass of the striking hammer of 0.9 kg, the swing angle of the striking arm of 47°, and the rotation speed of the cam of 100 r/min, then the soil removal rate was the maximum and the energy consumption of single-hammer knocking was the minimum, with the values of 89.12% and 31.21 J, respectively. This study can provide a reference for the design and optimization of soil removal devices for rhizome-type traditional Chinese herbal medicines.

The aim of this study was to detect the electrochemical characteristics of rice leaves under low‐temperature stress. This study uses the electrical impedance graph method and the electrolyte exostosis method under the condition of low‐temperature cold case study in the seedling stage of rice leaves, with a normal seedling stage of rice crops grown as controls. The shape of the electrical impedance map of rice leaves under low‐temperature stress and its change with the increase of low‐temperature stress were studied, and the change trend of electrical impedance map parameters with the increase of low‐temperature stress was statistically analyzed. At the same time, the two detection methods are discussed to establish the correlation. The results showed that the electrical impedance pattern was a complete, symmetrical, single half arc with rice leaves subjected to reversible damage. The left side of the arc starts to disappear with an irreversible injury. Rice tended to die when the arc on the right side of the impedance spectrum began to scatter. Moreover, the change in the electrical impedance spectrum was consistent with that of relative conductivity. When the rice was not dead, the extracellular resistance and relaxation time of leaves decreased with the increase of stress degree, and intracellular resistance increased. Indicating the electrical impedance spectroscopy (EIS) can be employed as a nondestructive testing method to detect physiological characteristics of rice leaves under low‐temperature stress.

Design and experiment of split-type tracked chassis applied in hilly and mountainous regions