This paper presents a fault-tolerant flight control method for a multi-rotor UAV under actuator failure and external wind disturbances. The control method is based on an active disturbance rejection controller (ADRC) and spatio-temporal radial basis function neural networks, which can be used to achieve the stable control of the system when the parameters of the UAV mathematical model change. Firstly, an active disturbance rejection controller with an optimized parameter design is designed for rthe obust control of a multi-rotor vehicle. Secondly, a spatio-temporal radial basis function neural network with a new adaptive kernel is designed. In addition, the output of the novel radial basis function neural network is used to estimate fusion parameters containing actuator faults and model uncertainties and, consequently, to design an active fault-tolerant controller for a multi-rotor vehicle. Finally, fault injection experiments are carried out with the Qball-X4 quadrotor UAV as a specific research object, and the experimental results show the effectiveness of the proposed self-tolerant, fault-tolerant control method.

WC–12Co coatings were deposited on 16Cr5Ni stainless steel substrate by high-velocity oxygen fuel (HVOF) process, followed by a one-hour heat-treatment in a tube furnace with a nitrogen atmosphere at 650, 800, 950, and 1100 °C, respectively. The influence of heat-treatment temperature on properties and cavitation erosion resistance of as-sprayed and heat-treated WC–12Co coatings was studied. The cavitation erosion test was carried out with ultrasonic cavitation erosion equipment. The porosity, microhardness, phase composition, as well as surface and cross-section morphology of the coatings were characterized. The coating heat-treated at 800 °C showed three typical cavitation erosion stages and exhibited the best cavitation erosion resistance. The cavitation erosion resistance was closely related to the coating microstructure and heat-treatment process. 3D optical microscopy was used to analyze the eroded surface of the coatings. The cavitation erosion mechanism of the coatings was discussed.

The dynamic effect in capillary pressure during the displacement process in ultra-low permeability sandstone reservoirs

Belt dryer is commonly used in the production of the dried aquatic feed. Poor airflow distribution during the aquatic feed drying process leads to moisture content variation that could be lead to high energy consumption and poor feed quality. A newly designed belt dryer with improved drying efficiency was used to study airflow distribution. In order to analyze airflow distribution inside the dryer, a model for a new belt dryer was established. Airflow distribution under five different feed thicknesses (20 mm, 30 mm, 40 mm, 50 mm, 60 mm) were simulated using computational fluid dynamics (CFD) techniques and verified by experimental data. A finite volume method with porous media formulation was used to simulate airflow distribution inside the dryer. The experimental results showed that there was good consistency between the experimental and simulated values of airflow velocity. The airflow velocity on the feed layer range from 0.28 m/s to 0.98 m/s with a standard deviation of up to 0.17 m/s. Airflow distribution inside the dryer was affected by the feed thickness and air space size. When the feed thickness was 40 mm, the uniformity of the airflow velocity at the surfaces of the feed can reach the best results.

In this paper, a prediction method of the heat transfer coefficient of composite vacuum glazing (CVG) is proposed. By analyzing the heat transfer process of CVG, the theoretical calculation formula for the heat transfer coefficient of CVG is established. CVG temperature variation under the test conditions specified in the national standard is simulated using ANSYS. The CVG heat transfer coefficient is calculated by combining the theoretical formula and simulation results. The simulation results are then verified by comparison to a physical experiment. The results show that the deviations between the experimental and predicted values are ≤3.8%, verifying the accuracy of the simulation results and proving that the model can be used in engineering practice. Furthermore, the effects of different coating positions on the heat transfer performance of CVG are studied. The results show that different coating positions have a significant impact on the heat transfer coefficient of CVG. The heat transfer coefficient is shown to be lowest to highest under the following conditions: when the Low-E coatings are located on both sides of the vacuum layer (2LC-V), followed by Low-E coatings on the side of glass pane II near the vacuum layer (1LC-V), Low-E coatings located on the side of glass pane I near insulating layer (1LC-I), and finally, when there are no Low-E coatings (NLC) on the glass panes. Overall, this model is an effective and accurate analysis method of the heat transfer coefficient.

This study aimed to assess the feasibility of a novel weeding and fertilization scheme, namely, mechanical weeding plus a one-time deep application of a reduced amount of slow-release fertilizer for rice cultivation. The effects of the weeding and fertilization method on rice yield and quality were investigated using a split plot test as the research method. Two weeding methods, namely, chemical weeding (CW) and mechanical weeding (MW), and four fertilization methods were tested, including the conventional fertilization method (quantitative split broadcast application of fast-release N fertilizer (CK)), the quantitative split broadcast application of 80% fast-release N fertilizer (LCK), the one-time base application of slow-release fertilizer (SR), and the one-time deep application of 80% slow-release fertilizer (LSR). The results showed that the rice yield under MW with LSR treatment can maintain a high level—higher than 9.2 t ha⁻¹ per year. This was attributed to the slow-release fertilizer and deep fertilization, which increased the number of stems and tillers in the pre-fertility and spike rate, respectively, resulting in a high panicle number with a 20% reduction of N fertilizer. Furthermore, mechanical weeding improved the seed-setting rate, resulting in a higher number of grains per panicle, a higher panicle number, and an increased thousand-grain weight, thereby maintaining a high yield. At the same time, the quality of rice under MW with LSR treatment improved, specifically reflected in the significant improvement of the processing and appearance quality of rice, a slight increase in protein content, and a reduction in the amylose content, thereby improving its nutritional quality while maintaining good cooking quality.