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Evacuators are key components of gun barrels, and their main function is to drain the gunpowder gas remaining in the gun bore from the muzzle by ejection. To design an efficient evacuator for the gun barrels, an optimization model with the mathematical expressions describing the working process of the evacuator was established. The four structural parameters that affect the efficiency of the evacuator, including the volume of the gas storage cylinder chamber, the distance of the nozzle from the muzzle end face, the cross-sectional area of the nozzles and the cross-sectional area of the valves, were optimized. The effective working time and reliability indicator of the optimized evacuator were improved. This work describes a framework for improving the design of highly efficient evacuators on gun barrels.

It is difficult to achieve a stably delicate operation in manual microsurgery, and the aim of this paper is to evaluate the robotic trephination that can open a promising perspective for the development of robotic microsurgical system for keratoplasty. A robot for corneal trephination integrating a force/torque sensor is designed based on manual trephine action. The manual experiments and the robotic experiments about penetrating trephination are performed in porcine eyes. The expected values of operational parameters that are references to the robotic trephination are obtained from the manual experiments using probability density functions (PDFs), including linear velocity, angular velocity, and rotating angle. Considering the meanings of the forces/torques, the results of the manual and robotic experiments such as trephine forces/torques and photomicrographs are compared to evaluate the effectiveness of robotic trephination. The manual trephination shows some randomness and this leads to large fluctuations in the trephine forces/torques during the surgery, but the robot may improve overall outcome of the graft, as it is able to carry out the operation stably and produce a uniform cutting margin. There is potential to improve the biomechanical properties in the delicate microsurgery by using the trephine robot and such devices can assist the surgeon to achieve a consistently high-quality result.