No abstract

No abstract

The protection of marine materials against corrosion using marine bacterial biofilms is a promising strategy. However, little is known about the mechanisms of this attractive corrosion prevention method. In this work, the corrosion behaviors of X80 carbon steel (CS) in the presence of three different marine Vibrio species were studied. The results demonstrated that all the three Vibrio spp. displayed significant corrosion protection with a weight loss reduction of up to 68%. Moreover, their corrosion prevention performance was tightly related to their abilities to form biofilms, which was in the order of Vibrio sp. EF187016 > Vibrio alginolyticus > Vibrio parahaemolyticus. To further investigate the corrosion prevention mechanism caused by marine biofilms, the extracellular polymeric substances (EPS) of Vibrio sp. EF187016 was extracted and added to 3.5 wt% NaCl for abiotic corrosion testing. The results suggested that the EPS inhibited corrosion, which means EPS can play a significant role in corrosion protection by biofilm.

No abstract

This paper mainly studies the obstacle avoidance and rapid reconstruction of UAV formations. A hybrid trajectory planning algorithm based on potential field fluid dynamic model and bidirectional fast search random tree is proposed to improve the ability of UAV formation to adapt to complex dynamic environment. Firstly, a dynamic system mathematical model based on fluid potential energy field is proposed; and the obstacle potential energy function and potential energy function between the formations modify the disturbance flow field. Secondly, IBi-directional Rapidly Exploring Random Tree (IBi-RRT) algorithm with adaptive step size is scheduled to solve the dispersive and convergent streamlines of disturbed flow field and to plan the trajectory. This method can clarify the flow field streamlines by adaptive step size combined with rolling detection method, which greatly improves the formation's ability to avoid dynamic threats. The experimental results show that the proposed improved fluid potential energy field dynamic system and IBi-RRT hybrid trajectory planning algorithm with adaptive step size can effectively improve the adaptive ability of UAV formation to the dynamic environment, and can plan the ideal trajectory in response to unexpected situations. INDEX TERMS Complex environment, fluid potential energy field, obstacles avoidance, sudden threats.