Quantitative analysis of the morphing wing mechanism of raptors: Bionic design of Falco Peregrinus wing skeleton.

The wing is one of the most important parts of a bird's locomotor system and is the inspiration origination for bionic wing design. During wing motions, the wing shape is closely related to the rotation angles of wing bones. Therefore, the research on the law of bone movement in the process of wing movement can be good guidance for the design of the bionic morphing wing. In this paper, the skeletal posture of the peregrine falcon wing during the extension/flexion is studied to obtain critical data on skeletal posture. Since an elbow joint and a wrist joint rotate correlatively to drive a wing to flex/extend, the wing skeleton is simplified as a four-bar mechanism in this paper. The degree of reproduction of wing skeleton postures was quantitatively analyzed using the four-bar mechanism model, and the bionic wing skeleton was designed. It is found that the wing motions have been reproduced with high precision.

The Performance and Mechanism of the Green Explosion Suppressant SGA for Coal Dust Explosion Suppression.

In recent years, coal processing is developing rapidly, but there are often hidden safety hazards such as coal dust explosions during coal processing. In order to ensure safe production and avoid coal dust explosion accidents, a carrier with unique micro-mesoporous structure (SG) based waste molecular sieves was prepared. After that, the carrier was loaded with (NH4)2C2O4(A) uniformly by ultrasound, which acted as an activity component for the first time. A novel micro-mesoporous coal dust explosion suppressant (SGA) is obtained. The law influence of different compositions of suppressant on the flame propagation of explosion was investigated. The results showed that the best ratio of waste molecular sieve, zirconium dioxide, and (NH4)2C2O4 of the suppressant is 1:7:2. The suppression performance increases with the increase of the addition of suppressant. When the addition amount is 70 wt %, the explosion loses the ability to continue to expand. Finally, combining the suppression performance with characterization results, the physical and chemical synergistic suppression mechanism is proposed, which reveals the reason why the suppressant has efficient suppression performance. The study could realize the green reuse of waste molecular sieves and provide guarantees for safe production of the coal processing industry.