Shantui (China)

This paper proposes a novel eddy current retarder (NECR) and thermal management method, aiming to solve the problems of low electromagnetic utilization rate, serious thermal decay of braking torque, and waste of braking energy in traditional eddy current retarder. The structure characteristics and working principle of NECR are introduced. The braking model is analyzed and calculated by using the equivalent magnetic circuit method. The transient magnetic field and temperature field of NECR are numerically simulated by finite element method. A thermal management method of NECR is proposed. And the braking force distribution strategy based on fuzzy control system is designed. And the braking force distribution strategy based on fuzzy control system is designed. The simulation results show that the heat generated by NECR can heat the electric bus cabin temperature to 19 °C. And the energy consumption of the vehicle is reduced by 28.8% compared to the use of electric energy to heat the cabin. The experimental results show that the average error between the experimental value and the simulation analysis value of braking torque is <5.8%. When the excitation current is 100 A and the rotating speed is 1500 rpm, the braking torque can reach a maximum of 2410 N·m. After continuous braking for 10 min, the braking torque decreases by only 13.7% and the temperature is stable within 100 °C.

Multi-cylinder synchronous control is critical for heavy machinery lifting operations, yet struggles to maintain precision under dynamic and asymmetric loads. Traditional strategies neglect the dynamic coupling between structural strain energy and hydraulic actuation, leading to energy accumulation and synchronization errors. This paper proposes a coordinated coupling control strategy based on dynamic strain energy balance. By decoupling lifting processes from synchronization control and integrating real-time strain energy feedback, the method dynamically compensates for deformation-induced deviations. A multi-physics co-simulation platform (MATLAB/AMESim-Adams) validates the approach, demonstrating significant improvements in synchronization accuracy and stability over conventional methods. Experimental results show the strategy reduces maximum synchronization errors by nearly half under variable loads while suppressing structural fatigue risks. This work advances high-precision multi-cylinder system design, with broader applications in heavy equipment requiring robust cooperative control.

Wet clutch, as a transmission system, plays a critical role in many mechanical applications, such as those in vehicles, ships, and helicopters. The performance of wet clutches significantly affects the overall transmission performance. Since their inception, wet multi-plate clutches have been a focal point of clutch research. With the widespread application of wet clutches, research in this area has become increasingly extensive and in-depth. Researchers have investigated the thermal characteristics of frictional pairs during engagement, by noting a sharp increase in frictional heat. To enhance vehicle smoothness during starting and shifting, friction and wear characteristics have also been studied. Additionally, considering the service life and safety of automobiles, researchers have conducted studies on life prediction of clutches. In wet dual-clutch systems, drag torque exists, impacting the control precision of torque transmission, vehicle transmission efficiency, and performance during starting and shifting. Researchers have also examined the characteristics of drag torque. This paper reviews recent advances in wet clutch research, analyzes the influence of friction plate groove structures on four research directions, and suggests that groove structure optimization should simultaneously consider its impact on all four areas.

Abstract As urbanization exposes wildlife to new challenging conditions and environmental pressures, species that exhibit a high degree of behavioral plasticity are considered potentially capable of colonizing and adapting to urban environments. However, differences in the behavior of populations that inhabit urban and suburban landscapes pose unprecedented challenges to traditional methods in wildlife management which often fail to consider a species’ needs or mitigate human–wildlife conflict due to changes in species behavior in response to intensive human interference. Here, we investigate differences in the home range, diel activity, movement, and diet of raccoon dogs (Nyctereutes procyonoides) between residential districts and forest park habitats in Shanghai, China. Using GPS tracking data from 22 individuals, we find that the home ranges of raccoon dogs in residential districts (10.4 ± 8.8 ha) was 91.26% smaller than those in forest parks (119.6 ± 135.4 ha). We also find that raccoon dogs in residential districts exhibited significantly lower nocturnal movement speeds (134.55 ± 50.68 m h−1) compared to their forest park counterparts (263.22 ± 84.972 m h−1). An analysis of 528 fecal samples showed a significantly higher intake of ingredients from human food in residential districts (χ 2 = 4.691, P = 0.026), which indicates that urban raccoon dog foraging strategies differ from the forest park population due to the presence of discarded human food, cat food, and wet garbage in residential districts. Based on our findings, we propose a community-based wildlife management strategy and suggest modifying the current design of residential districts. Our results underscore the importance of mammal behavior studies in urban biodiversity management and provide a scientific basis for mitigating human–wildlife conflicts in urban environments in and beyond our study area.

Abstract Human‐wildlife interactions become increasingly common in urban areas across all continents and ecosystem types. Depending on the context, human‐wildlife interactions can be categorized as harmonious, neutrality, or in conflict and raises cultural, economic and ecological challenges in maintaining urban biodiversity. Understanding the mechanism behind the tolerance of residents to the presence of wildlife is vital to promoting a harmonious coexistence between humans and wildlife in urban environments. To advance our knowledge of this mechanism, we developed a questionnaire to survey residents in Shanghai, China about their knowledge of and attitude towards raccoon dogs (Nyctereutes procyonoides), a species whose population is increasing in urban areas. Using 281 questionnaires, we conducted structural equation modelling to examine how relational values, including familiarity with raccoon dogs, perceived benefits and risks, together with residents' trust in wildlife management authorities, interactively influence the tolerance for this species. We found that the residents' familiarity with raccoon dogs positively influenced their tolerance, both directly and indirectly through increased perceived benefits and reduced perceived risks. Furthermore, trust in wildlife management authorities contributed to higher tolerance through perceived benefits. Our results suggested that education about the relational values of raccoon dogs to the public can reduce the traditional negative connotation for this species and promote the coexistence of people and raccoon dogs in Shanghai urban environment. Based on our understanding about how raccoon dogs were culturally constructed and the willingness of residents to share landscapes with the species, we advocate that relational values play an important role in future urban biodiversity conservation planning. We also advocate for education programs that familiarize the public with raccoon dogs as well as other species, which can turn urban human‐wildlife conflicts into harmonious relationships in Shanghai and other urban areas. Read the free Plain Language Summary for this article on the Journal blog.

In order to improve the overall performance of edge plates such as bulldozer blades, composition and heat treatment processes were optimized on the martensitic wear-resistant steel grade 400 HB. Steel billets were first obtained through smelting in a state of hot rolling, followed by quenching and tempering to obtained wear-resistant steel (HB400). Then, HB400 was subjected to metallographic observation, electron backscatter diffraction (EBSD) testing, and transmission electron microscope (TEM) characterization and property testing. The results showed that HB400 exhibited microstructural refinement, characterized by narrower martensite laths and finer grains. The EBSD results indicated a uniform microstructure with a low content of the residual austenite (0.5%), indicating good hardenability. TEM observation of the martensite matrix revealed the presence of substructures, i.e., numerous dislocations in martensite laths. The average Rockwell hardness (HRC) of HB400 was 46.3, and the average Brinell hardness (HB) was 402. A mechanical properties test demonstrated comprehensive properties, which showed that the ultimate tensile strength and yield strength of HB400 were 1495 MPa and 1345 MPa, respectively, with a relative elongation of 12%. Friction and wear experiments showed that the friction coefficient and wear rate in reciprocating mode decreased by 16.1% and 45.4%, respectively, while in rotating mode, they decreased by 27.6% and 2.1%, respectively, as the load increased from 100N to 300N. According to the wear morphology, the main wear mechanisms were identified as adhesive wear, abrasive wear, and oxidative wear. The lubricating effect of the oxide layer generated by wear was identified as the primary reason for the reduction in the friction coefficient. The relationship between microstructures and properties was discussed based on grain refinement strengthening and dislocation strengthening.