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Transport is an integral part of the nuclear fuel cycle. The procedures employed are designed and conducted to ensure the public and environment protection both routinely and when transport accidents occur. According to this, the purpose of this paper is to focus on a coupled thermal-drop impact analysis-based safety assessment of a nuclear fuel cask.

For the cask, high altitude falling and fire accidents are the two most serious accidents during its transportation. In this paper, a sequentially coupled thermal-drop impact analysis is performed by using a nuclear fuel cask model for safety assessment. High altitude falling and fire accidents of the nuclear fuel cask were conducted by using finite element simulations for coupled thermal-drop impact analysis.

Results showed that the cask can withstand a drop test and survive a fire of 800°C for 30 minutes. In addition, an improved design is explored and evaluated, which provides a reference for structural design and safety assessment of nuclear fuel casks.

A coupled thermal-drop impact analysis-based safety assessment procedure is developed for the nuclear fuel cask.

This study aims to design a controller which can improve the end-effector low-frequency chattering resulting from the measurement noise and the time delay in the on-orbit tasks. The rendezvous point will move along the rendezvous ring owing to the error of the camera, and the manipulators’ collision need be avoided. In addition, owing to the dynamics coupling, the manipulators’ motion will disturb the spacecraft, and the low tracking accuracy of the end-effector needs to be improved.

This paper proposes a minimum disturbance controller based on the synchronous and adaptive acceleration planning to improve the tracking error and the disturbance energy. The synchronous and adaptive acceleration planning method plans the optimal rendezvous point and designs synchronous approaching method and provides an estimation method of the rendezvous point acceleration. A minimum disturbance controller is designed based on the energy conservation to optimize the disturbance resulting from the manipulator’s motion.

The acceleration planning method avoids the collision of two end-effectors and reduces the error caused by the low-frequency chattering. The minimum disturbance controller minimizes the disturbance energy of the manipulators’ motion transferred to the spacecraft. Experiment results show that the proposed method improves the low-frequency chattering, and the average position tracking error reduces by 30%, and disturbance energy reduces by 30% at least. In addition, it has good performances in the synchronous motion and adaptive tracking.

Given the immeasurability of the target satellite acceleration in space, this paper proposes an estimation method of the acceleration. This paper proposes a synchronous and adaptive acceleration planning method. In addition, the rendezvous points are optimized to avoid the two end-effectors collisions. By the energy conservation, the minimum disturbance controller is designed to ensure a satisfying tracking error and reduce the disturbance energy resulting from the manipulators’ motion.

Autonomous mobile robots (AMRs) play a crucial role in industrial and service fields. The paper aims to build a LiDAR-based simultaneous localization and mapping (SLAM) system used by AMRs to overcome challenges in dynamic and changing environments.

This research introduces SLAM-RAMU, a lifelong SLAM system that addresses these challenges by providing precise and consistent relocalization and autonomous map updating (RAMU). During the mapping process, local odometry is obtained using iterative error state Kalman filtering, while back-end loop detection and global pose graph optimization are used for accurate trajectory correction. In addition, a fast point cloud segmentation module is incorporated to robustly distinguish between floor, walls and roof in the environment. The segmented point clouds are then used to generate a 2.5D grid map, with particular emphasis on floor detection to filter the prior map and eliminate dynamic artifacts. In the positioning process, an initial pose alignment method is designed, which combines 2D branch-and-bound search with 3D iterative closest point registration. This method ensures high accuracy even in scenes with similar characteristics. Subsequently, scan-to-map registration is performed using the segmented point cloud on the prior map. The system also includes a map updating module that takes into account historical point cloud segmentation results. It selectively incorporates or excludes new point cloud data to ensure consistent reflection of the real environment in the map.

The performance of the SLAM-RAMU system was evaluated in real-world environments and compared against state-of-the-art (SOTA) methods. The results demonstrate that SLAM-RAMU achieves higher mapping quality and relocalization accuracy and exhibits robustness against dynamic obstacles and environmental changes.

Compared to other SOTA methods in simulation and real environments, SLAM-RAMU showed higher mapping quality, faster initial aligning speed and higher repeated localization accuracy.

The purpose of this paper is to analyse how different strengths of simmelian ties affect knowledge spirals and investigate which major factors affect the influence of simmelian ties on knowledge spirals.

The empirical data in this paper were collected through e-mail and interview questionnaires to R&D teams in high-tech manufacturing enterprises in China. The authors obtained 132 teams' valid responses. The interval decision-making trial and evaluation laboratory (interval DEMATEL) method, differential evolution (DE) algorithm and Bayesian structural equation modelling (BSEM) were employed to test the theoretical framework developed for this paper.

The results show that strong simmelian ties have positive associations with high-performance work practices (HPWPs). Meanwhile, weak simmelian ties have positive associations with HPWPs. Furthermore, HPWPs and knowledge fermentation play a conducive role in the relationship between simmelian ties and knowledge spirals.

This paper contributes in three ways. First, it extends research on the relational antecedents of knowledge spirals. Second, this paper extends the study of social capital related to knowledge spirals. Third, this paper elucidates less familiar factors relating HPWPs to knowledge fermentation by testing the mediating role of HPWPs in knowledge fermentation.

The purpose of this paper is to clarify agricultural services into five categories, including agricultural materials supply service, financial service, technical service, machinery service and processing and sales service, and to examine the effect of agricultural services on cost saving of rice production in China.

Based on a three-year panel data set covering 3,421 rice farmers in 12 Chinese provinces collected from the state rice industry experiment stations’ fixed watch points of China Agriculture Research System, a stochastic frontier model which takes the price vectors of input variables into cost function is developed by stochastic frontier analysis method in the study.

There is a deviation between the actual cost and the minimum cost on rice production in China due to the loss of cost efficiency, whose score is 0.7983 at the mean. Agricultural services can help improve cost efficiency, thus contributing to cost saving. Specifically, the effect of technical service on cost saving is the highest, followed by processing and sales service, machinery service, financial service and agricultural materials supply service.

The results of this paper are of great significance to the effectiveness and efficiency of the targeted agricultural services and indicate implications for policy improvement under the context of clear upward trend of agricultural production costs.

An elasto‐viscoplastic analysis of anisotropic plates and shells is undertaken by means of the finite element displacement method. A thick shell formulation accounting for shear deformation is considered and a layered approach is adopted in order to model property changes through the shell thickness. In order to avoid ‘locking’ behaviour as the shell thickness is reduced, the nine‐node Lagrangian and heterosis elements are introduced into the present model. Viscoplastic yielding is based on the Huber—Mises criterion extended by Hill for anisotropic materials. Time integration of the strain rate equations is accomplished by both explicit and implicit algorithms and special consideration is given to the evaluation of the viscoplastic strain increment for anisotropic situations. The computer code developed is demonstrated by application to a range of numerical examples.

The purpose of this paper is to investigate the applicability of the smoothed particle hydrodynamics (SPH) method in the jet formation process of a cylindrical-shaped charge (CSC). Different SPH formulations, suggested in other works, to other applications, are brought together in order to build a model that represents the phenomenon of detonation of a CSC in a more realistic way.

A two-dimensional (2D) SPH formulation using cylindrical coordinates is adopted to simulate CSCs. The problem of fluid-solid interaction between the detonation wave of the explosive and the metal liner, numerically unstable due to the great difference in density between the phases, is resolved adopting the multi-phase strategy. A new proposition of artificial viscosity is incorporated in order to account the convergence effect of the liner particles toward the axis of symmetry of the charge. Two numerical examples are used to validate the formulation. In the first, the velocity and length differences between the jets formed from a CSC and a linear-shaped charge (LSC) using planar detonation on both are compared. In the second example, the effect of the conical cavity angle in the maximum jet velocity is evaluated, comparing the simulated results of CSC with four different cavity angles, with the experimental results.

The results show that the 2D SPH method in cylindrical coordinates is able to simulate the detonation process of a CSC. Accordingly with the formulations used, the following conclusions can be made: the multi-phase strategy is able to capture the multi-material interface of the fluid-solid interaction between the detonation wave and the metal liner; and in the cylindrical geometry, a second artificial viscosity is necessary in order to include the convergence effect of the particles toward the axis of symmetry and obtaining more realistic results for the jet velocity.

The applicability of the SPH method to simulate LSCs has been tested and verified in other works, but there are not references that address the application of the SPH method to simulate CSCs. CSCs are widely used in the defense industry and in the oil industries. In the oil industry, the perforating process may currently be the most common use of such a device. For this reason, it is believed that the proposed formulation in this paper is a good alternative to these specific applications.

The purpose of this paper is to develop a new rectilinear branch pipe‐routing algorithm for automatic generation of rectilinear branch pipe routes in constrained spaces of aero‐engines.

Rectilinear branch pipe routing that connects multiple terminals in a constrained space with obstacles can be formulated as a rectilinear Steiner minimum tree with obstacles (RSMTO) problem while meeting certain engineering rules, which has been proved to be an NP‐hard and discrete problem. This paper presents a discrete particle swarm optimization (PSO) algorithm for rectilinear branch pipe routing (DPSO‐RBPRA) problems, which adopts an attraction operator and an energy function to plan the shortest collision‐free connecting networks in a discrete graph space. Moreover, this paper integrates several existing techniques to evaluate particles for the RSMTO problem in discrete Manhattan spaces. Further, the DPSO‐RBPRA is extended to surface cases to adapt to requirements of routing pipes on the surfaces of aero‐engines.

Pipe routing numeral computations show that, DPSO‐RBPRA finds satisfactory connecting networks while considering several engineering rules, which demonstrates the effectiveness of the proposed method.

This paper applies the Steiner tree theory and develops a DPSO algorithm to plan the aero‐engine rectilinear branch pipe‐routing layouts.

A generalized displacement method has been previously presented for the analysis of thin plate‐shell structures with the use of bilinear 4‐node isoparametric shell elements. Following this approach, a procedure for the geometrically non‐linear analysis of thin plates and shells based on both updated and total Lagrangian formulations is developed. The results of some numerical examples are presented to show the versatility and effectiveness of the method.

Ant colony algorithm is widely used in recent years as a heuristic algorithm. It provides a new way to solve complicated combinatorial optimization problems. Having been enlightened by the behavior of ant colony's searching for food, positive feedback construction and distributed computing combined with certain heuristics are adopted in the algorithm, which makes it easier to find better solution. This paper introduces a series of ant colony algorithm and its improved algorithm of the basic principle, and discusses the ant colony algorithm application situation. Finally, several problems existing in the research and the development prospect of ACO are reviewed.