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The purpose of this paper is to model and predict suitable gait trajectories of lower-limb exoskeleton for wearer during rehabilitation walking. Lower-limb exoskeleton is widely used for assisting walk in rehabilitation field. One key problem for exoskeleton control is to model and predict suitable gait trajectories for wearer.

In this paper, the authors propose a Deep Spatial-Temporal Model (DSTM) for generating knee joint trajectory of lower-limb exoskeleton, which first leverages Long-Short Term Memory framework to learn the inherent spatial-temporal correlations of gait features.

With DSTM, the pathological knee joint trajectories can be predicted based on subject’s other joints. The energy expenditure is adopted for verifying the effectiveness of new recovery gait pattern by monitoring dynamic heart rate. The experimental results demonstrate that the subjects have less energy expenditure in new recovery gait pattern than in others’ normal gait patterns, which also means the new recovery gait is more suitable for subject.

Long-Short Term Memory framework is first used for modeling rehabilitation gait, and the deep spatial–temporal relationships between joints of gait data can obtained successfully.

Based on social cognitive theory, this study aims to explore the effect of authentic leadership on employee green creativity by studying the mediating role of reflection and rumination and the moderating role of psychological capital.

This study used experience sampling methodology to test hypothesis. Specifically, this study applied two-level path analysis to analyze 1,290 observations from 129 employees.

The results show that authentic leadership positively influences reflection but negatively influences rumination, which in turn impact employees’ green creativity. Psychological capital positively moderates the effects of authentic leadership on reflection and negatively moderates the effects of authentic leadership on rumination. Furthermore, psychological capital moderates the linkages between authentic leadership, self-reflection and employee green creativity.

Organizations should make efforts in promoting authentic leadership and recruiting employees who possess high psychological capital. Moreover, managers can make effective efforts to stimulate employees’ reflection and mitigate rumination, thereby facilitating organizational sustainable development.

In investigating green issues related to employees’ daily cognitive processes, this study focuses on within-personal reaction mechanism to authentic leadership, concerning the moderating effect of individual psychological capital.

The purpose of this paper is to explore the operating characteristics of gallium-based liquid metals (GLMs) by directly adding them as lubricants in real mechanical equipment.

This paper conducts an analysis of the rotor-bearing system under GLM lubrication using a constructed test rig, focusing on vibration signals, surface characteristics of the friction pair, contact resistance and temperature rise features.

The study reveals that GLM can effectively improve the lubrication condition of the tribo-pair, leading to a more stable vibration signal in the system. Surface analysis demonstrates that GLM can protect the sample surface from wear, and phase separation occurs during the experimental process. Test results of contact resistance indicate that, in addition to enhancing the interfacial conductivity, GLM also generates a fluid dynamic pressure effect. The high thermal conductivity and anti-wear effects of GLM can reduce the temperature rise of the tribo-pair, but precautions should be taken to prevent oxidation and the loss of its fluidity.

The overall operating characteristics of the rotor-bearing system under GLM lubrication were investigated to provide new ideas for the lubrication of the rotor-bearing system.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-03-2024-0067/

In the field of planetary exploration, the legged-type lander is a common landing buffer device. There are two important performance metrics for legged-type landers: the energy absorption capacity and landing stability. In this paper, a novel method is proposed to optimize the honeycomb buffer of a legged-type lander. Optimization design variables are the dimension parameters of honeycomb and the objective functions are the evaluation parameters of the above two performance metrics.

A multi-body dynamic model of a lander and a finite-element model of the metal honeycomb are established. Based on the simulation results of the finite-element model and the quartic polynomial, the surrogate models are established to evaluate the energy absorption capacity of honeycomb. Considering both the multi-body dynamic model and the surrogate models, the study designed the optimization flow of dimension parameters of honeycomb. Besides, the non-dominated sorting genetic algorithm II is used for iterative calculation.

Images of surrogate models show the monotonous functional relationship between the honeycomb’s energy absorption characteristics and its dimension parameters. Optimization results show an apparent contradiction among the objective functions. Besides, according to the simulation results, this method can significantly improve the comprehensive performance of the lander.

The novel method can effectively reduce the cost of honeycomb compression tests and improve the lander’s design. Therefore, it can be used for optimizing buffers of other types of legged-type landers.

This study aims to accurately simulate the tilting separation process of mask projection stereolithography (MPSL) and verify the tilting theory.

The finite element separation models of MPSL 3D printing process were established. The established models simulated both tilting and pulling-up separation process by changing the constraints and boundary conditions. The bilinear cohesive curves were used to define the separation interface. The stress distribution of the cured part and FEP film at different times during the whole separation process was extracted. Different orientations of pulling-up and tilting were also compared for stress distribution. The stress change was analyzed for the center and edge points of the upper surface of cured part.

The results showed that the stress increased with the separation speed, and the stress at the edge position of exposure area was greater than the internal position. The tilting traction stress distribution was affected by the exposure area function and the velocity distribution. Alternation of the exposure area function changed the cohesive stiffness. The non-coincidence of the calculated traction stress with the input bilinear cohesive curve reflected the influence of the material properties and the separation methods. The high-speed side of tilting had fast separation and high traction stress.

This study proposes a technical method for simulation tilting separation and verified the tilting theory. The cohesive zone model was proved applicable to the tilting traction stress calculation.

The purpose of this paper is to study the landing performance of the Mars lander considering uncertain landing conditions under two landing modes.

A dynamics analysis model for the legged Mars lander is established for landing simulation, where the nonlinear large-deformation flexible buffer rods are equivalently modeled with a rigid-body mechanism with external forces and movement limit. Sensitivities of the landing stability to various landing conditions are analyzed using the Quasi–Monte-Carlo-based Sobol’ method and computer-aided landing simulations. Moreover, based on the results of sensitivity analysis, sensitive parameters are selected for estimating the safe boundaries for stability indices of rotation and clearance.

It can be concluded from this study that the lander has excellent ability against overturning. The shutdown-before-touchdown strategy helps to maintain than landing pose, and the shutdown-at-touchdown strategy helps to prevent the nozzle from colliding with the surface of Mars.

This study provides a theoretical reference to choose the better landing strategies for Mars landers considering uncertain landing conditions.

A parameterized dynamics Mars lander model and a simplification method are proposed to simulate the landing on Mars. Uncertain landing conditions are parameterized and considered in the dynamics model. Sensitivity analysis and safe boundary methods are used to compare the landing performances with two landing strategies.

In the process of conveying the solid–liquid two-phase medium of the centrifugal slurry pump, the wear of the flow-passing parts is an important problem affecting its life and safe operation. Therefore, a numerical investigation on the wear characteristics of the centrifugal slurry pump under different particle conditions was conducted.

A solid-liquid two-phase model based on CFD-DEM coupling is established and used to analyze the flow field and the wear characteristics of the flow-passing parts with different particle densities, volume fractions and sizes.

Particle conditions will affect the pump flow field. To analyze the pump wear characteristics, the wear distribution, wear value and cumulative force laws of flow-passing parts under different particle conditions are obtained. In each flow-passing part, with the increase of particle density, volume fraction and size, the wear area is concentrated and the wear depth increases. Under different particle conditions, the wear is mainly on the volute chamber and the blade pressure surface, and the tangential cumulative force of flow-passing parts is much larger than the normal cumulative force.

An accurate model and a coupled simulation method for predicting the wear of the slurry pump are obtained, and the wear characteristic law can provide a reference for the design of the slurry pump to reduce friction.

This paper aims to investigate the damage evolution of bearing raceways under impact conditions from the perspective of three-dimensional (3D) surface morphology changes and to analyze the causal factors with the aid of simulation.

An experimental device containing an impact generating mechanism, a transmission mechanism and a torque load is designed for the experiments of impact damage to the outer raceway of a small needle roller bearing HK1208 without an inner ring. Microscopic images and height color maps of each experimental stage were obtained using a 3D laser measurement microscope. The characterization parameters of the surface 3D morphology were extracted and analyzed. Dynamics simulations of the impact condition were performed using the finite element method to investigate the variations and distribution characteristics of the roller forces on the raceway.

The changes in roughness and 3D micromorphology show that the surface flattening phenomenon caused by the flattening effect occurs before the surface of the bearing raceway is damaged. The result of dynamic simulations shows that the maximum load of the bearing under the impact state is obviously greater than that under a steady state, and the load distribution under the two conditions is significantly different.

This paper provides new ideas for analyzing the damage of bearings under impact conditions by analyzing the real 3D morphology of bearing raceways in combination with the finite element method.

The deposition of particles onto a substrate during the cold spraying (CS) process relies on severe plastic deformation, so there are various micro-defects induced by insufficient deformation and severe crushing. To solve the problems, many post-treat techniques have been used to improving the quality by eliminating the micro-defects. This paper aims to help scholars and engineers in this field a better and systematic understand of CS technology by summarizing the post-treatment technologies that have been investigated recently years.

This review summarizes the types of micro-defects and introduces the effect of micro-defects on the properties of CS coating/additive manufactured, illustrates the post-treatment technologies and its effect on the microstructure and performances, and finally outlooks the future development trends of post-treatments for CS.

There are significant discoveries in post-treatment technology to change the performance of cold spray deposits. There are also many limitations for post-treatment methods, including improved performance and limitations of use. Thus, there is still a strong requirement for further improvement. Hybrid post-treatment may be a more ideal method, as it can eliminate more defects than a single method. The proposed ultrasonic impact treatment could be an alternative method, as it can densify and flatten the CS deposits.

It is the first time to reveal the influence factors on the performances of CS deposits from the perspective of microdefects, and proposed corresponding well targeted post-treatment methods, which is more instructive for improving the performances of CS deposits.

The purpose of this paper is to examine the post-enactment status of China’s Labour Contract Law and Labour Dispute Mediation and Arbitration Law, focusing on the dramatic rise in remuneration litigation amidst much criticism of weak or ineffective implementation of these laws.

This paper deploys both quantitative and qualitative analysis methods to investigate the features of remuneration litigation. Remuneration judgments by Beijing People’s Courts from 1 January 2014 to 31 December 2017 provide the primary empirical data. The intrinsic features of remuneration disputes are investigated to delineate subcategories of claims. Several judges were also interviewed to further explore the nature of remuneration disputes.

Four types of remuneration claims were identified: regular wage, minimum wage, overtime and others (including subsidies and welfare). Examination of these four types, especially how they are processed until concluded by court adjudication, provides a fuller picture of the post-enactment status of these laws and yields objective and rational findings. To explain the continuing steady rise in the volume of remuneration claims, as more workers have knowledge of their rights and access to the courts, this study identifies an increase in the number of factually complicated cases (e.g. overtime claims) and abmiguity in the relevant law, leaving some remuneration disputes difficult, if not impossible, to adjudicate. Conversely, the study also finds significant positive trends following these laws’ enactment, particularly a reduction in straightforward cases, such as disputes concerning non-payment of wages/minimum wages, on which the law is clear. It is evidently imperative to improve the clarity of the current laws through further legislation, as the most appropriate next step in China’s juridification process of developing its own rule of Labour Law.

This study is purposely limited to examining remuneration litigation in Beijing’s courts from 2014 to 2017, which is representative of the national trend of dramatically rising remuneration disputes, and thus provides valuable insights. Future studies should cover a wider geographic territory and other categories of labour disputes to provide an even more comprehensive picture of the challenges and potential solutions.

By understanding the driving factors of rising labour remuneration disputes, the legislature, workers and employers can act accordingly to curb labour conflicts. The growing complexity and technicality of remuneration litigation indicates that the pressing need of labour juridification is to deploy a subtle, comprehensive method to improve legal clarity and judicial professionalism.

This study uniquely divides the types of remuneration litigation in Beijing, adopting methods and yielding findings absent from the prior literature. Both the progress and challenges in China’s rule of Labour Law process are reflected in this work, together with public policy and theoretical implications for further study.