Anaerobic digestion (AD) is an effective way to utilize the abundant resource of corn stover (CS). In this light, Ca(OH)₂ pretreatment alone, steam explosion (SE) pretreatment alone, and co-pretreatment of Ca(OH)₂ and SE were applied to improve the digestion efficiency of CS. Results showed that AD of co-pretreated CS with 1.0% Ca(OH)₂ and SE at 1.5 MPa achieved the highest cumulative methane yield of , which was 61.54% significantly higher (p < .01) than untreated CS. The biodegradability value of CS after co-pretreatment enhanced from 43.03% to 69.52%. Methane yield could be well fitted by the first-order model and the modified Gompertz model. In addition, composition and structural changes of CS after pretreatment were analyzed by a fiber analyzer, scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. The validated results indicated that co-pretreatment of Ca(OH)₂ and SE was efficient to improve the digestion performance of CS and might be a suitable method for agricultural waste pretreatment in the future AD industry.

This paper focuses on the steering motion control of an in-wheel motor-drive robot. The influence of the pulse-width modulation (PWM) duty cycle on steering motion and the steering control method have not yet been proved. Thus, this study aimed to design a steering controller for the off-center steer-by-wire system of a robot. The influence of the PWM duty cycle on the steering motion under different conditions is firstly tested on a test bench. Based on the optimal duty cycles of different cases found in the test, a two-stage fuzzy controller of the duty cycle is designed for the steering system. The first stage of the controller is used to dynamically adjust the PWM duty cycle of the electromagnetic friction lock (EFL). The second stage is designed to realize the self-tuning of the fuzzy controller’s quantization factor and the scale factor. Through two-stage control, the motion of the in-wheel motor and the EFL can be coordinated to realize stable and rapid steering. Considering the robots’ primary application in field roads at present, road tests were ultimately conducted to verify the proposed method. The test results show that the angle response rate of the steering arm is elevated with the increase in the steering angle signal. The proposed controller can sensitively track the target angles with smaller overshoot, yaw rate and lateral acceleration, and better steering accuracy than the PID (proportional–integral–differential) controller under different working conditions.

In order to solve problems of raw materials present in the compost reactor are compacted blocks, poor ventilation performance, large ventilation resistance, and difficulty in homogenizing the product, a helical ribbon and screw impeller aerobic compost bioreactor was developed. Through numerical simulation of the flow field, it is proved that the helical ribbon and screw impeller has a good agitation and axial flow property. The results of the composting test show that the time above 55°C for the top, middle, and bottom layers is 5.2, 4.7, and 4.3 days. During the reaction, the oxygen concentration was over 8%, and the final seed germination index of each layer was over 88%, which proved that the experimental reactor can achieve homogenization and can be effectively harmless compost.

Simulated annealing optimization and experiments of a five-bar aerating mechanism for vertically aerating on salt-affected lands