Search Results (510)

Tire pressure is a key factor influencing vehicle dynamic behavior, controllability, and handling performance. This study investigates the effect of tire pressure distribution on steady-state cornering and self-steering behavior near the handling limit. Experimental tests were performed on standardized constant-radius circular tracks at the ZalaZONE Dynamic Platform using winter and summer tires. Starting from the manufacturer-recommended reference pressure, the vehicle was tested at increasing speeds until the slip limit was approached. Symmetric and asymmetric front–rear tire pressure configurations were evaluated to assess their influence on steering demand, lateral acceleration, and handling balance. The results indicate pressure-dependent changes in steering angle demand, achievable lateral acceleration, and self-steering characteristics under the investigated test conditions. Asymmetric front–rear pressure distributions were found to modify the understeer–oversteer balance, highlighting the importance of tire pressure distribution in vehicle controllability near the handling limit. The findings provide practical trend-level insights for future studies on vehicle dynamics, stability control, and steering assistance functions, particularly in operating conditions where tire pressure may deviate from nominal values. Full article

Injuries to the posterolateral corner (PLC) of the knee represent a complex clinical entity that is frequently underdiagnosed and undertreated, often leading to persistent instability and failure of concomitant ligament reconstructions. Although open surgical approaches to the PLC have been extensively described, the role of arthroscopy in the diagnosis and management of these injuries remains less clearly defined despite increasingly encouraging clinical and biomechanical results. The aim of this narrative review was to analyze the role of knee arthroscopy in the diagnosis, evaluation, and treatment of PLC injuries. A comprehensive literature review was performed focusing on studies investigating arthroscopic findings, diagnostic signs, and arthroscopic or arthroscopy-assisted techniques for PLC management. Relevant clinical, anatomical, biomechanical, and surgical studies were analyzed to provide an integrated arthroscopy-oriented perspective. Arthroscopy enables direct visualization of key posterolateral structures and identification of characteristic diagnostic findings, such as the lateral drive-through sign, potentially improving detection of subtle or combined PLC injuries. In addition, arthroscopic assessment facilitates evaluation of associated intra-articular lesions and may contribute to more accurate characterization of injury patterns. Emerging arthroscopic and arthroscopy-assisted reconstruction techniques may offer advantages in selected cases by supporting tailored surgical strategies, accurate graft positioning, and reduced surgical morbidity. Knee arthroscopy is assuming an increasingly important role in the comprehensive management of PLC injuries, extending beyond the treatment of associated intra-articular pathology alone. Integration of arthroscopy into the diagnostic and therapeutic algorithm of PLC injuries may improve surgical decision-making and patient-specific management. Nevertheless, further high-quality clinical studies are required to establish standardized arthroscopic criteria and validate the long-term clinical advantages of arthroscopy-guided approaches. Full article

Biomass co-firing is an effective approach for improving the low-carbon and flexible operation of coal-fired boilers under deep peak-shaving conditions. In this study, a 3D CFD model was established for a subcritical four-corner tangentially fired boiler to investigate the effects of biomass blending percentage, injection position, and boiler load on combustion characteristics and NO formation. The results show that increasing the biomass blending percentage improves the uniformity of the flow and temperature fields, promotes more complete pulverized coal combustion, and enhances boiler combustion efficiency. Among the investigated load conditions, the 70% load shows a relatively more favorable combustion state in terms of flow field distribution, temperature level, and species distribution. Compared with B-layer primary air injection, BC-layer secondary air injection shows a stronger tendency to reduce NO formation under the simulated conditions. These results indicate that proper biomass blending and optimization of the injection position can effectively improve combustion uniformity and suppress NO formation. Full article

Leftover spaces, often associated with neglected urban corners, bear physical and conceptual similarities to ignored parts of designed wholes. This study proposes an analytical approach to develop resilient intervention strategies by analyzing the production of leftover spaces through users’ emotional experiences. An experimental pilot study was conducted along Söğütlüçeşme Street in Kadıköy, Istanbul, where all corner points were typologically classified based on morphological characteristics. To measure the impact of these configurations on spatial emotional characters, a survey was implemented using Plutchik’s wheel of emotions. Following a quantitative analysis of emotion frequencies and intensities, findings were visualized via radar charts and spatialized using QGIS 3.40 to generate an emotional map. The resulting emotional maps were further used to identify spatial vulnerabilities and resilience priorities across the study area. By making the gaps between point-based emotional clusters continuous through the IDW interpolation method, the emotional topography of the study area was modeled, thereby presenting an analytical framework that identifies emotional thresholds, spatial vulnerabilities, and resilience priorities. Results indicate that as the physical boundaries of corner voids expand, influenced by angling and massing decisions, public diversity increases, creating a positive emotional atmosphere. Conversely, compressed voids demonstrate a higher potential for producing leftover spaces. This study reveals that mapping user emotions as a data layer is critical for constructing more inclusive and resilient urban environments. Full article

Given the widespread application of multi-story modular container building structures, this article proposes a new seismic isolation system called the “sliding friction isolation system (IS)” that utilizes friction energy dissipation between containers. Firstly, lateral stiffness tests were conducted on a 20 ft container, a 40 ft container, and 20 ft connected containers. The constraint consists of four fixed-bottom corner pieces, and the load is achieved using a symmetrical longitudinal concentrated loading method. Their stiffness values were 58.07 kN/mm, 33.41 kN/mm, and 60.03 kN/mm, respectively, providing the necessary parameters for IS. Secondly, an IS model was established, and based on the theory of random vibration, the relationship between c_ei (the equivalent damping of i layer of the structure) and μ (the inter-layer friction coefficient) of the system was obtained. Thirdly, a nonlinear finite element model of a six-story container building was established. Namely, the non-isolation system with standard damping ratios (NIS-sdr), the non-isolation system with equivalent damping ratio (NIS-edr), and the IS. Elastic-plastic nonlinear time-history analyses were then conducted to study the dynamic responses of three systems under strong earthquakes. The analyses yielded the top displacement of the structure, each structural layer’s maximum displacement and displacement angle, the slip of each layer, the hysteresis loops, and the cumulative dissipated energy of IS. The results show that compared to NIS sdr and NIS edr, IS can effectively reduce the maximum interlayer displacement. The largest angular displacement between the structural layer of IS and NIS-edr is far less than that of NIS-sdr. The spectral characteristics of seismic waves (the EL-Centro wave, Taft wave, and artificial wave) can significantly affect the dynamic response of IS. Additionally, the length of the sliding hole on the corner piece can be set to 35 mm based on the displacement of each layer under the Taft wave to meet the standards for container houses (T/CECS 1932-2025). Full article

Facility agricultural robots operating in greenhouse environments often encounter narrow passages, dense obstacle distributions, and frequent path-direction changes, which increase the difficulty of achieving efficient and smooth autonomous navigation. Conventional A* algorithms usually suffer from redundant node expansion, dense turning-point distributions, and insufficient path continuity under such constrained conditions. To address these issues, this study proposes an improved A*-based path-planning framework that integrates adaptive heuristic weighting, dynamic corner correction, and Bézier-curve-based path smoothing. Rather than introducing an entirely new planning paradigm, the proposed method coordinates several existing optimization strategies within a unified framework to improve search efficiency, path regularity, and path continuity for facility agricultural scenarios. The adaptive heuristic weighting strategy dynamically adjusts the contribution of the heuristic term according to the relative distance between the current node and the target node, thereby improving global search guidance while reducing unnecessary exploration. Dynamic corner correction is introduced to suppress zigzag path structures and reduce redundant turning nodes in obstacle-dense regions, while Bézier-curve-based smoothing is employed to improve path continuity and compatibility with the kinematic characteristics of agricultural mobile robots. Simulation experiments were conducted on grid maps and greenhouse-like environments with different obstacle distributions, and comparative evaluations were performed against Dijkstra, RRT, and conventional A* algorithms. Under representative simulation scenarios, the proposed framework reduced the number of turning points by up to 53.7% and decreased computation time by approximately 19.4% compared with the conventional A* algorithm, based on the average results of repeated trials under identical conditions. In addition, physical platform experiments on a ROS2-based agricultural robot demonstrated that the planned trajectories maintained relatively stable navigation performance and smoother directional transitions in constrained greenhouse-like environments. The results indicate that the proposed framework achieves a more balanced trade-off between computational efficiency, path compactness, and path smoothness than the benchmark methods considered in this study. Nevertheless, the current validation remains limited to structured or semi-structured greenhouse environments under static obstacle conditions. Future work will focus on improving adaptability to dynamic agricultural scenarios and integrating the framework with real-time perception and motion-control systems for practical greenhouse deployment. Full article

The emergence of selective laser melting (SLM) has enabled the fabrication of complex structures with exceptional mechanical performance. However, process-induced defects, including porosity and geometric deviations, pose significant challenges to structural reliability, and their dynamic evolution under loading remains poorly understood. In this study, helical layered square honeycomb structures were fabricated via SLM. The effects of process conditions on defect characteristics, as well as the influence of porosity and wall thickness defects on mechanical properties, were investigated using X-ray computed tomography (CT), in situ loading tests, and finite element simulation. The results indicate that the investigated high-quality process conditions minimize porosity, optimize pore morphology, and improve wall thickness uniformity, thereby substantially reducing the adverse effects of pores on tensile properties. Under compressive loading, defect evolution, including pore expansion and wall thickness thinning, is primarily concentrated at structural corners, with more pronounced variations observed under coarse process conditions. Increased porosity, wall thickness reduction, and uneven thickness distribution all degrade the quasi-static compressive performance and medium to high-velocity impact resistance of the structure. Furthermore, thickness distribution exerts an independent influence on mechanical properties beyond the effect of overall average thickness. Full article

To investigate the flow characteristics of three-dimensional swept interactions, 3D steady Reynolds-averaged Navier–Stokes (RANS) simulations are conducted at an incoming Mach number of 3.5 and a Reynolds number of 30,955 based on the incoming boundary-layer thickness δ₀. Three independent compression configurations with a total compression angle of 18° are analyzed and compared: planar swept shocks, curved swept shocks featuring an initial 2° deflection step followed by a continuously curved compression surface, and continuous isentropic compression waves. The results demonstrate that, unlike the baseline planar case, the interactions induced by both curved swept shocks and isentropic compression waves depart from the canonical quasi-conical similarity and transcend existing topological classification frameworks. These non-planar interactions are characterized by large-scale primary vortices and small-scale corner vortices that evolve along curved trajectories downstream. Quantitatively, the curved shock interaction yields maximum normal scales of 5.4δ₀ for the primary vortex and 1.8δ₀ for the corner vortex—significantly more compact than the 6.7δ₀ and 7.5δ₀ observed in the planar-shock interaction. Furthermore, the specific modality of compression—whether by discrete shock or continuous wave—exerts a profound effect on aerodynamic performance. Under the present conditions, while isentropic compression achieves the highest compression efficiency and planar shocks provide superior mass flow capture, curved shock compression strikes a favorable balance between these competing metrics. Curved shock configurations may offer potential for improving integrated inlet performance through appropriate adjustment of the initial shock strength. Full article

Traditional coal mining methods have led to prominent issues of coal resource waste and large-scale solid waste emissions. The integrated “excavation–backfilling–retention” mining technology for inter-section coal pillars and gate roads is one of the key technologies to solve these problems. However, the excavation and mining process associated with this technology imposes higher requirements on the ventilation system. Aiming at addressing the ventilation challenges existing during the implementation of the “excavation–backfilling–retention” method, research on ventilation safety assurance technology for inter-section coal pillars was carried out. Using COMSOL5.5 software, a full-stage ventilation system design model was constructed, adopting a ventilation mode that combines full-air-pressure ventilation with auxiliary local ventilation. The dynamic variation characteristics of the ventilation system under the “excavation–backfilling–retention” method and its capability to prevent and control the risks of O₂ and CO gas accumulation and coal spontaneous combustion were studied. The results show that during the bypass excavation period, the air supply from the auxiliary fan is sufficient, and during the excavation period for the two gate roads, due to the increased ventilation distance, insufficient airflow occurs near the heading face, accompanied by temperature rise, O₂ concentration decrease, and local CO accumulation, posing risks of coal spontaneous combustion and toxic gas accumulation. During the inter-section coal pillar excavation period and the cyclic operation period, after the full-air-pressure ventilation system is established, the airflow becomes stable, ventilation resistance decreases, and both temperature and gas concentrations are controlled within safe limits. However, in the corner areas, auxiliary local ventilation measures are still required due to insufficient O₂ and CO accumulation. The study verifies the feasibility and safety of the integrated “excavation–backfilling–retention” ventilation system, providing a safe ventilation approach for the integrated mining method and supporting the green mining of coal mines and the synergistic development of coal-based solid waste resource utilization. Full article

Optical and Synthetic Aperture Radar (SAR) image registration is a fundamental task in remote sensing information fusion, yet it remains challenging due to significant differences in imaging mechanisms, radiation characteristics, and noise properties between the two modalities. Existing public datasets suffer from limited resolution, small scale, and insufficient scene diversity, and these limitations have hindered algorithm development. This paper constructs a large-scale, high-resolution optical–SAR registration dataset based on the HongTu-1 satellite 3-m SAR imagery and Google Earth optical imagery at zoom level 17, covering diverse scenes across China with a standardized pipeline including terrain correction, geometric alignment, standardized slicing, and quality filtering. Building upon this dataset, a hand-crafted keypoint-based cross-modal registration method is proposed, incorporating multi-level edge filtering and hybrid feature detection. Unlike conventional hand-crafted methods such as RIFT, SRIF, and LNIFT, which mainly refine keypoint detection, description, or matching within a SIFT-style pipeline, the core novelty of this work lies in SAR-specific preprocessing and multi-level hybrid filtering. These components are designed to suppress speckle while extracting more stable and discriminative shared edge responses for cross-modal registration. An improved Log-domain Total Variation (Log-TV) denoising model is introduced for SAR preprocessing. A hybrid edge filtering framework combining phase congruency analysis and Structured Random Forest (SRF) edge detection is constructed within a Gaussian scale space. A dual-branch feature detection scheme integrating blob and corner features is designed with a robust orientation assignment strategy. Feature description uses the Gradient Location–Orientation Histogram (GLOH) descriptor with Principal Component Analysis (PCA) reduction, while geometric estimation employs the Fast Sample Consensus (FSC) algorithm. Experiments on the self-constructed HT dataset and on the public OSdataset and SAR2Opt benchmarks show that the proposed method consistently achieves low RMSE and high success rates. It also maintains competitive efficiency among hand-crafted methods while retaining strong robustness to scale and rotation variations. Full article

Brush seals, as a fundamental dynamic sealing technology in the aerospace and energy propulsion industries, require performance enhancement through instantaneous adjustment of the friction coefficient and force analysis of brush filaments. This paper establishes an instantaneous friction coefficient correction method based on the open volume between bristles and the backing plate. The downstream section of the double-row brush wire (2.6 mm) was quantitatively identified as the maximum leakage point, and it was found that the vortex characteristic length in the downstream area is approximately 1–3 times the bristle gap, with an increasing pressure ratio enhancing downstream turbulence and reducing gas leakage. A cantilever beam structural model was developed to assess the motion, force, and hysteresis properties of a single filament. Additionally, a porous medium model was utilized to elucidate the flow field and temperature distribution within the seal. The results suggest that the lag angle increases linearly over the first one-third of the brush wire’s length from the free end to the fixed end and is directly proportional to the pressure difference ΔP, reaching a maximum of 10.18°. The viscous drag causes the radial force y-component F_xy to increase and then decrease near the free end. The rear baffle contact force, F_b, shows variable peaks at two-thirds of the filament length. The displacement at the brush filament’s free end, the deflection angle, and the bending moment are directly proportional to the pressure differential. As pressure increases, the deformed region propagates toward the fixed end, and the maximum displacement at the free end of the brush wire reaches 13.04 mm. The leakage rate increases nearly linearly with ΔP and its deformation, reaching a maximum of 0.00849 m²/s. The pressure gradient growth rates of 164%, 73%, and 29% at the front baffle corner demonstrate that adding pressure chambers on front and rear baffles is optimal for high-pressure scenarios (ΔP > 0.3 MPa), while the formation of vortices between bristles and rotor reduces tip friction force and front-row turbulent disturbance, providing design guidance for extending seal service life. Full article

Traditional Chinese brick-and-stone archways are not merely architectural products shaped by geographical constraints; they also embody a highly rational structural logic. Drawing on the unique earthen environment of the Loess Plateau and the region’s traditions of brick-and-stone construction, the Jinzhong region of China has developed a distinct system of archways. Consequently, to deconstruct the mechanical wisdom inherent in the traditional building techniques of the Jinzhong region, this study selected residential buildings in Qi County and Pingyao, as well as Qing Dynasty (1636–1912 AD) official architecture, as case studies. Through field investigations into the masonry techniques of three typical vault forms—the single-centre arch, the double-centre arch, and the four-centre arch—the study revealed their evolutionary characteristics in terms of geometric form. Static numerical simulation analysis was conducted using the Abaqus CAE 2025 (Dassault Systèmes, Vélizy-Villacoublay, France) platform. The study found that, under a simulated surface load of 0.027 N/mm², different arch profiles exhibited significant quantitative mechanical differences, and their stress distributions and deformation thresholds showed distinct scenario-specific tendencies. The results show that, compared to a semicircular arch, the official double-centred arch reduces maximum displacement by approximately 20%, and the maximum principal stress decreased from 1.35 MPa to 1.215 MPa, effectively mitigating the risk of cracking at the arch crown. With this high sectional stiffness and displacement-constraining capability, it supports the high load requirements of defensive city fortifications. Compared to the Pingyao gentle-type four-centre arch, its maximum displacement increased by only about 10%, and the maximum principal stress rose by only about 8%. Therefore, given similar mechanical performance but considering construction feasibility, the official double-centred arch was selected for the construction of defensive city fortifications. Furthermore, although the stress concentration at the corners (arch feet) of the Pingyao gentle-curved four-centred arch is approximately 4.8% higher than that of the pointed four-centred arch, its spatial utilization is improved by 15–20%; This geometric trade-off achieved through composite curvature maximizes interior clear space while maintaining structural stability, aligning with the functional requirements of guyao architecture for large-span living spaces. Meanwhile, the semicircular vaults of Qi County demonstrate universal value in low-load residential door and window components due to their low construction threshold. These quantitative data and qualitative observations indicate that the evolution of traditional forms is not merely an esthetic pursuit, but rather a precise optimization of structural performance within the constraints of material strength. This coupled relationship between “geometric form, load-bearing mechanism and usage context” confirms the inherent principles of resource efficiency and performance balance within traditional building systems. The quantitative assessment framework established in this study provides scientific guidance, grounded in construction logic, for the preventive conservation and precise reinforcement strategies of historic masonry structures. Full article

For autonomous vehicles, high-speed cornering can easily lead to degraded handling stability and increased risks of sideslip or even rollover. Therefore, vehicle phase-plane stability-region analysis has become an important topic in active safety-control research. However, most existing studies still construct phase-plane stability regions mainly based on simplified vehicle models, without sufficiently considering the influence of vertical load transfer during cornering on tire lateral forces and stability boundaries. To address this issue, this paper proposes a hierarchical control strategy based on phase-plane analysis for active inward tilt vehicles. This method adopts a three-degree-of-freedom vehicle dynamics model and a tire model. By carefully comparing the phase-plane stability regions of active inward tilt and passive roll vehicles and by further analyzing the state-trajectory convergence characteristics of active inward tilt vehicles under different longitudinal speeds, front wheel steering angles, and road adhesion coefficients, the effects of active inward tilt on stability-region expansion and vehicle-state convergence are revealed. Subsequently, a hierarchical control strategy is proposed as an integrated solution to improve vehicle handling stability. The upper-level controller dynamically adjusts the reference values and objective weights according to whether the vehicle state is located in the stable, critical, or dangerous region. The lower-level NMPC controller optimizes the front wheel steering angle and active suspension forces to achieve coordinated trajectory tracking and stability control. Double lane-change simulation results show that active inward tilt can improve the left–right vertical load distribution and expand the lateral stability region. Compared with passive roll and conventional active inward tilt control, the proposed strategy reduces the phase-plane state convergence area by 68% and 75%, respectively, thereby improving vehicle handling stability and active safety under extreme conditions. Full article

To investigate the wind-induced vibration of a single-axis solar tracker, this study employs a combination of rigid model pressure measurement wind tunnel tests and finite element calculations. This study addresses the critical gap of full-array wind-induced response analysis and provides region-specific dynamic amplification factor recommendations applicable to comparable tracker configurations. The wind load distribution on the solar tracker surface is obtained through rigid model pressure measurement tests; the natural frequency and mode of the solar tracker are determined via finite element calculations; and the wind-induced response of the solar tracker is computed by integrating the wind load and its self-vibration characteristics. At small tilt angles, a shielding effect is observed, with the wake region exhibiting a lower standard deviation of the torque coefficient than the windward region, whereas at large tilt angles, an amplification effect is observed, with the wake region exhibiting a higher standard deviation. The wind-induced vibration of the solar tracker is predominantly characterized by torsional vibration around the main axis, with larger torsional displacements observed in the end regions and the area between the two drive posts. Furthermore, recommended dynamic amplification factors are provided: 2.07~2.41 for the corner regions, 1.85~1.92 for the mid-span regions, and 1.98~2.23 for the end regions. Full article

This study analyzes the effects of different moonpool configurations on drillship hydrodynamics using the Reynolds-averaged Navier–Stokes (RANS) equations. A three-dimensional numerical wave tank is established to realize the prediction and validation of the hydrodynamic performance of irregular waves and the interaction between irregular waves and structures. Combined with the selection of the drillships with relatively favorable resistance performance among different moonpool configurations under calm-water navigation conditions, further studies are carried out on the motion characteristics and drag-reduction optimization of the rectangular- and square-moonpool drillships under irregular wave conditions. Comparative analysis of the numerical results shows that different moonpool shapes result in different drag-increase effects under calm-water conditions, and the moonpool-induced drag increase mainly originates from added residuary resistance. Relative to the non-moonpool baseline drillship, the installation of a moonpool under irregular wave conditions notably elevates the resistance amplitude and amplifies the heave and pitch responses, with a more prominent impact observed on pitch, while also modifying the natural frequency characteristics of the moonpool-equipped drillship. Introducing appropriate rounded corners at the bottom of the moonpool can effectively reduce the resistance of the moonpool drillship and significantly decrease the amplitudes of heave and pitch responses under irregular wave conditions. Based on the present study, a bottom rounded-corner radius of 40 mm effectively improves the hydrodynamic performance of the moonpool drillship in irregular waves. The numerical results provide direct theoretical and design guidance for drag reduction and motion-performance enhancement of moonpool-equipped drillships, highlighting their engineering applicability. Full article