Hydroponic lettuce was prone to pest and disease problems after transplantation. Manual identification of the current growth status of each hydroponic lettuce not only consumed time and was prone to errors but also failed to meet the requirements of high-quality and efficient lettuce cultivation. In response to this issue, this paper proposed a method called YOLO-EfficientNet for identifying the growth status of hydroponic lettuce. Firstly, the video data of hydroponic lettuce were processed to obtain individual frame images. And 2240 images were selected from these frames as the image dataset A. Secondly, the YOLO-v8n object detection model was trained using image dataset A to detect the position of each hydroponic lettuce in the video data. After selecting the targets based on the predicted bounding boxes, 12,000 individual lettuce images were obtained by cropping, which served as image dataset B. Finally, the EfficientNet-v2s object classification model was trained using image dataset B to identify three growth statuses (Healthy, Diseases, and Pests) of hydroponic lettuce. The results showed that, after training image dataset A using the YOLO-v8n model, the accuracy and recall were consistently around 99%. After training image dataset B using the EfficientNet-v2s model, it achieved excellent scores of 95.78 for Val-acc, 94.68 for Test-acc, 96.02 for Recall, 96.32 for Precision, and 96.18 for F1-score. Thus, the method proposed in this paper had potential in the agricultural application of identifying and classifying the growth status in hydroponic lettuce.

Excess water seriously affects the performance and lifetime of proton exchange membrane fuel cells (PEMFCs). This study proposes a novel compound flow field, which is named the active drainage flow field (ADFF). The new design enhances the drainage performance by under-ribs flow, while the output performance is very close to that of the conventional serpentine flow field (CSFF). Additionally, the ADFF bipolar plate has been taken as a cathode while retaining CSFF as an anode; the combination shows a good output performance under high relative humidity. The peak power density has reached to 0.59 W/cm², which is 13% higher than that of the CSFF.

In order to grasp the particle flow characteristics and energy consumption of industrial fluidized spouted beds, we conduct numerical simulations on the basis of a Computational Particle Fluid Dynamics (CPFD) approach. In particular, the traction model of Wen-Yu-Ergun is used and different inlet conditions are considered. Using a low-speed fluidizing gas, the flow state of the particles is better and the amount of particles accumulated at the bottom of the bed wall becomes smaller. For the same air intake, the energy loss of a circular nozzle is larger than that of a square nozzle.

In this paper, a method to improve the performance of PEMFCs using porous material as a flow channel baffle is proposed. The results show that PEMFCs with four porous baffles flow channels have better performance at high current density compared with the traditional flow channel. The structural parameters of the flow channel explored in this study include porosity, the thickness of the baffle and the number of baffles, and their influence on the performance of PEMFCs. Sensitivity analysis results show that the performance of the PEMFCs with the porous baffle channel is the most sensitive to baffle thickness, and the thickness and baffle could be appropriately adjusted. The number of plates and porosity of the baffle are adjusted to improve the performance of the PEMFCs.

When cleaning the surface of a glass greenhouse, the washing machine often encounters slippery tracks or strong winds, in which case the washing machine is very likely to deviate from the axis of the greenhouse. In order to improve the stability and reliability of the glass greenhouse cleaner under different working conditions, this paper studies the controller of the glass greenhouse cleaner and puts forward a fuzzy PID control scheme optimized by the PSO algorithm. Using Adams and Matlab to jointly simulate the machine model, the results show that the particle swarm fuzzy PID controller has the best control effect and can make the cleaner adaptable to a variety of working conditions. The system overshoot was reduced by up to 35.5%, the response time by up to 3 s, and the difference between left and right wheel speeds by up to 0.086 deg/s.

In order to address the time-consuming and labor-intensive challenges as well as the suboptimal operational quality encountered in the conventional processes of fruit bagging within expansive orchards, an innovative end-of-bagging actuator is proposed, which can be installed on a fruit-production robot. Due to the excessive power sources required to complete the bagging operation, while also taking into account the quality and cost of the end effector, we have implemented a clutch transmission system to control individual motors, thereby achieving efficient bag-opening and collection actions. Through kinematic analysis of the bagging end effector, the optimal bag opening size is determined to be 40.3372 mm, with a deviation of 0.1428 mm from the design target and an error rate of 0.35%. This ensures the desired bag size for bagging juvenile fruits. Moreover, a dynamic simulation model comprising rigid drive components and a flexible clutch was developed. The simulation results demonstrate the system’s stable performance. However, it is evident that the gear speed falls below that of the flexible clutch, resulting in insufficient bag opening and bag gathering compared to the intended design target. The observed phenomenon is a result of the characteristics exhibited by the flexible clutch. Specifically, the demands for bagging and stretching can be accommodated by modifying the stiffness and geometric configuration of the flexible clutch, alongside the level of operational force. To conclude, the suggested end effector can successfully simulate the implementation of the manual bagging process. By taking into account the quality and cost of the end effector, a clutch drive system was utilized to regulate a single motor, resulting in efficient bag-opening and collection actions. This approach offers a more integrated and efficient solution compared to manual bagging and semi-automatic mechanically assisted bagging methods.