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Multistage synchronous induction coilgun (MSSICG) has higher launch efficiency than other electromagnetic guns due to excellent noncontact propulsion characteristics. However, the feeding of the coil array must be synchronized with the movement of the projectile to accelerate the load smoothly. Researchers usually adopt tedious step-by-step debugging to achieve the matching of trigger timing and other structural parameters, but lack of detailed derivation and demonstration of critical trigger criterion. Therefore, starting from the optimal coupling position of single-stage launcher, this article proposes the critical trigger criterion. Then, the extended trigger criterion is modified by analyzing the simplified conditions and adjustable parameters of MSSICG with different structural forms. The research aims to provide reference for the parameter design of MSSICG.

Accurate detection and measurement of hairline cracks on metal parts, typically less than 1 mm wide, are important for remanufacturing. However, this task remains challenging due to the small crack size, high reflectance of the metal surface, and the lack of reliable real-size measurement methods. This article proposes an image-based identification method that addresses these challenges and enables precise detection and measurement of hairline cracks on metal surfaces. This method establishes a controllable imaging system with a blue dome light source to capture uniformly illuminated and high-contrast images. This setup overcomes the primary difficulty of high reflectance associated with detecting cracks on metal surfaces. Furthermore, the imaging system incorporates camera calibration to convert pixel size to real size accurately, offering significant practical value beyond mere crack localization and segmentation at the pixel level. A new hairline crack identification algorithm based on morphology is developed to extract pixels of the hairline cracks directly, followed by real-size calculation. The experimental results validate the proposed method’s effectiveness, achieving an accuracy of approximately 97% and 90% for millimeter- and submillimeter-level hairline cracks, respectively. Moreover, the average error and standard deviation surpass those of previous crack measurement techniques, demonstrating the proposed method’s superiority.

Byline: Xiaobo. Niu, Hao. Peng Objective: The objective of this study is to investigate the effects of lipopolysaccharide (LPS) on the growth rate of MG-63 cells. Materials and Methods: MG-63 [...]