With the increase of mining depth in coal mines, coal-rock-gas compound dynamic disasters are becoming more frequent. The unclear disaster mechanisms, inaccurate monitoring and early warning systems, incomplete evaluation frameworks, and relatively blind prevention and control measures urgently need to be addressed. This paper systematically reviews the disaster mechanisms of coal-rock-gas compound dynamic disasters, exploring the spatiotemporal coupling relationship between dynamic ground pressure and coal and gas outbursts in the compound disasters process. It proposes a chain-reactive, instantaneous model of “impact-induced outbursts” for hard coal seams and a long-period, guidance-type model of “outburst-induced dynamic pressure” for weak coal seams. In terms of monitoring methods for coal-rock-gas compound dynamic disasters, the paper provides a detailed discussion of structural monitoring, stress monitoring, and gas monitoring technologies, analyzing the impact of coal and rock physical-mechanical parameters and gas parameters on disaster risk. For risk assessment, the paper combines existing hazard evaluation models for dynamic ground pressure and coal and gas outbursts, introducing the concepts of intrinsic structural factors and engineering structural factors to construct a risk zoning system for coal-rock-gas compound dynamic disasters. Regarding prevention and control strategies, the paper centers on structural regulation for disaster mitigation, proposing active prevention and control measures by artificially adjusting the height of the caving zone and optimizing the roof angle. Finally, based on the current research progress, the paper offers prospects for future research directions and key challenges.

Bainite transformation has long been a major research focus in materials science, particularly the development of quantitative models for its transformation kinetics. In this study, the morphological evolution, kinetics, effects of prior austenite grain size (PAGS), and the influence of fast cooling rate on lower bainite (LB) transformation kinetics of a high-strength low-alloy steel were investigated. Laser scanning confocal microscopy, thermal simulation, and electron backscattered diffraction experiments were utilized. A specific kinetic equation for LB transformation was established. The results demonstrated that: (i) the kinetic constant was approximately proportional to the logarithmic volumetric PAGS and the square of cooling rate; (ii) the nucleation number per unit volume decreased with increasing PAGS; and (iii) the overall LB packet growth rate increased with both PAGS and cooling rate. The key factor in obtaining fine LB packets was to increase the nucleation number per unit volume of LB, which could be achieved through two approaches: reducing PAGS and modulating the cooling rate. However, reducing PAGS had a much stronger effect compared to modulating the cooling rate.

The differences in the microstructure, mechanical properties, and intergranular corrosion performance of three Al-Cu-Mg-Ag alloys with varying Cu content were analyzed. The results show that Cu content primarily affects the precipitation of intragranular Ω and S′ phases, as well as the type and distribution of grain boundary precipitates (GBPs). As the amount of Cu increases, the diameter and volume fraction of the Ω phase increase, while the proportion of the S′ phase first increases and then decreases. The alloy with high Cu content exhibits higher strength, mainly due to a larger contribution from precipitate strengthening (mainly the Ω phase) and strengthening provided by additional Cu atoms. However, the lower number density of the Ω phase results in poor fatigue resistance. The GBPs transition from the intermittently distributed S phase to the continuously distributed S and θ phases, which is the main reason for the decrease of intergranular corrosion resistance in high Cu alloys and also has some impact on the fatigue resistance of the alloy. Electrochemical characteristics also show that high Cu alloys have higher free corrosion current density and corrosion rate, lower polarization resistance, and smaller charge transfer resistance of the double layer and inductance values.

The effects of Al addition on microstructure and mechanical properties of an extruded Mg-Y-Zn-Co (MYZC) alloy were investigated. The addition of Al into the alloy refined dendrite of as-cast MYZC alloy, promoted the precipitation of a great number of long period stacking order (LPSO) phases with a 18R structure at dendritic boundaries and facilitated the formation of (Al,Zn)₂Y phases. After homogenization treatment, a fraction of the lamellar 18R-LPSO phases at grain boundaries transformed into the fine strip-like 14H-LPSO phases within the grains. During extrusion, compared with the extruded MYZC alloy, the extruded Mg-Y-Zn-Co-Al (MYZCA) alloy exhibited a finer grain size of ∼2.76 µm, and a weaker basal texture. Tensile test results indicated that the extruded MYZCA alloy exhibited the excellent strength-ductility synergy, whose yield strength, ultimate tensile strength, and elongation at fracture were 309.6 MPa, 398.5 MPa, and 22.2%, respectively. The high tensile strengths at room temperature were primarily attributed to grain refinement and secondary phase strengthening, while the good ductility was mainly owing to texture weakening and the activation of non-basal dislocations.

This study delved into the influence of pre-aging on the creep behavior and mechanical properties of an Al-Zn-Mg-Cu alloy subjected to high creep level. The creep strain was improved significantly for both pre-aged (120 °C for 6 h) and T4 samples under high creep stresses (280 MPa). Notably, pre-aging endowed the alloy with a long “peak-aging strengthening zone” during high-stress creep aging. This can effectively extend the creep aging time and enhance the creep strain while maintaining high strength of the alloy. This may stem from the additional consumption of vacancies and solute atoms by the pre-aging treatment, inhibiting the transformation of the η′phase into the η phase. Moreover, the pre-aging promotes the formation of fine, high density, and uniformly distributed η′ phase. It can also reduce the diffusion of solute atoms from inter grain to grain boundaries (GBs) during high-stress creep aging. This effectively impeded the coarsening of precipitates at GBs, reducing the width of the precipitation-free zone, and consequently minimized plasticity loss induced by high creep stress. Therefore, a suitable pre-aging can make the samples still maintain outstanding mechanical properties during the high-stress creep aging, which opens a new way of thinking to enhance the creep deformation behavior and aging-strengthening behavior in a synchronized manner. In particular, this provides a new approach to address the tendency of large rib-stiffened tank plates to develop high-stress zones during creep aging, leading to over-aging.

(AlCoCrFeNi_2.1)p/6061Al matrix composites were prepared by vacuum hot pressing sintering, and the mechanical properties and corrosion performance were investigated. Microstructural characterization reveals that a ring-like transition layer formed between the high-entropy alloy particle (HEAp) and the 6061Al matrix, there were some monoclinic structural phases distributed along the outside of the transition layer, and these are presumed to be Al₉ (CoCrFeNi)₂. With increasing sintering temperature, the hardness, densification and yield strength of composites improved. Compression morphology indicates that the existence of the transition layer is necessary to effectively prevent the expansion of crack in the 6061Al, resulting in composites that exhibit good plasticity. Galvanic coupling corrosion formed when the composites were tested in simulated seawater, the boundary between the transition layer and the 6061Al matrix was preferentially corroded to form a ring-shaped corrosion pit, and the thickness of the transition layer would affect the ring-shaped corrosion pit. It could be controlled within a certain thickness by adjusting the sintering temperature of the composites to improve the corrosion resistance. These findings demonstrate the critical role of the transition layer in balancing mechanical properties and corrosion resistance of HEAp-reinforced aluminum composites.

Ca-Mn based perovskites are particularly suitable for large-scale chemical looping applications due to their low cost and tunable performance characteristics in chemical looping with oxygen uncoupling (CLOU). However, these materials still struggle to simultaneously achieve long-term stability and efficient oxygen uncoupling performance. Herein, an innovative Co/Mg co-doping strategy was proposed. The optimization threshold for the single Co doped system could achieve 110% enhancement in oxygen uncoupling performance compared to undoped CaMnO₃, but exhibiting irreversible phase separation and severe sintering above 800 °C. The Co/Mg co-doped system was further developed to significantly improve high-temperature cycling stability, maintaining the superior oxygen uncoupling performance. It was found that Mg doping substantially enhanced the activity of the primary redox pairs (Mn⁴⁺/Mn³⁺, Co³⁺/Co²⁺), demonstrating the stable oxygen uncoupling capacity of 1.67 wt%–2.12 wt% at 900 °C. The developed Ca-Mn based perovskite oxygen carrier achieves an optimal balance between efficient oxygen uncoupling capacity and high-temperature structural stability, providing a novel material for enhanced fuel conversion for CLOU application.

The conversion of biomass-derived aldehydes via waste shell-derived catalysts is vital for sustainable chemistry, yet green batch synthesis of such catalysts from raw biomass remains underexplored. This study uses crab shells, a kitchen waste, combined with ZrCl₄ via non-toxic hydrothermal synthesis to scale-prepare Zr-containing polyphenolic biopolymer catalyst (Zr-Ch). Comprehensive characterizations revealed that the robust coordination between Zr⁴⁺ ions and phenolic hydroxyl groups in waste shell resulted in the formation of potent Lewis acid-base pair sites (Zr⁴⁺-O²⁻). The synergistic effect of diverse acid-base sites in Zr-Ch enabled exceptional catalytic efficiency for the Meerwein-Ponndorf-Verley (MPV) reaction of furfural (FF) to furfuryl alcohol (FA) with a remarkably lower activation energy of 22.2 kJ/mol, which greatly reduced the reaction temperature to 100 °C. Consequently, a quantitative yield of FA as high as 94.9% and a selectivity for FA of 98.9% were achieved. This research expanded waste shell applications and illuminated acid-base interaction mechanisms in biomass molecule reduction.

The effect of fluoride ions on the coordination properties and kinetic parameters of vanadium ions in molten salts was investigated. The competitive coordination process of V(III) with Cl⁻ and F⁻ and its mechanism were investigated by combining electrochemical and spectroscopic techniques and ab initio molecular dynamics (AIMD) simulations. The electrochemical behavior of V(III) in melt LiCl-KCl-KF with various F/V molar ratios was studied by cyclic voltammetry, square wave voltammetry and open circuit potentiometry at 823 K. The morphology of V(III) in the molten salt was observed by Raman spectroscopy. Combining mathematical calculations and AIMD simulations, it is concluded that VCl₄F₂³⁻ is the most stable complex in the melt at 823 K. In addition, the diffusion coefficients of V(III) were calculated to be between 6.79×10⁻⁵ cm/s and 2.68×10⁻⁴ cm/s under various contents of KF. The kinetic mechanism of V(III) was studied by electrochemical impedance spectroscopy and the exchange current density i₀=1.27–2.89 A/cm², and the reaction rate constant k₀=1.69×10⁻⁶–3.84×10⁻⁶ cm/s. This work aims to provide a theoretical basis for the mechanistic study and process optimization of vanadium electrolysis from molten salts.

The demand for accurate acetone gas sensors in low-concentration detection is rapidly increasing in applications such as air safety monitoring and non-invasive diabetes diagnosis. In this study, a freeze-drying strategy is developed to synthesize LaFeO₃ with abundant oxygen vacancies and enhanced specific area. The acetone sensors based on above LaFeO₃ exhibit high response and excellent selectivity. Typically, the response is 125 for 50 ppm acetone, nearly 1.5 times that of materials prepared by the sol-gel method, and the detection limit is 19.3 ppb. The ppb-level acetone detection of the freeze-dried LaFeO₃ nanoparticle sensor can be attributed to the abundant oxygen vacancies and enhanced specific surface area, which provides more active sites for sensing. This not only provides a promising strategy for improving acetone sensor performance, but also lays the foundation for tuning the micro-nanostructure to enhance gas sensor capabilities.

Oleic acid is a commonly used fatty acid collector in fluorite flotation, known for its effective collecting performance and cost-effectiveness, but with a limited selectivity. In this study, a novel collector, α-sulfonate group mixed acid (α-SMA), is introduced. The flotation test results demonstrate that the α-SMA collector provides significantly better selectivity in fluorite flotation. Specifically, the α-SMA collector exhibits a similar collecting ability to oleic acid for fluorite; however, its capacity to collect calcite is substantially lower. Zeta potential tests indicate that, under identical dosage conditions, α-SMA adsorbs in greater quantities on fluorite than on calcite. As a result, fluorite exhibits substantially higher flotation recoveries versus calcite with α-SMA collector. X-ray photoelectron spectroscopic analysis suggests that α-SMA facilitates a higher electron donation to Ca²⁺ ions on fluorite compared to calcite surface, forming stronger chemical bonds with fluorite surface. This enhanced interaction leads to stronger adsorption of α-SMA on fluorite. Furthermore, when α-SMA adsorbs solely through its sulfonic group, its carbon chain is positioned almost parallel to calcite surface. This configuration significantly reduces the hydrophobicity of the calcite surface, leading to very low calcite recovery rates with α-SMA collector.

As clean energy technologies advance, the engineering challenges caused by rapid thermal fluctuations are expected to become more complex. This study investigates the damage behavior of granite subjected to rapid heating and cooling, focusing on the underlying damage evolution processes. A range of experimental and computational methods, including nuclear magnetic resonance (NMR), synchronous thermal analyzer (STA), and discrete element method (DEM), were used. The results show that as temperature increases, material density, P-wave velocity, and dynamic elastic modulus decline exponentially, while the damage index and linear thermal expansion coefficient increase. Thermal damage primarily results from dehydration, thermal expansion, decarbonation, plasticization, phase changes, cracking, and decomposition. Thermal shock decreases the contribution of micropores to total porosity, while macropores grow above 200 °C. The study also improves the Schlumberger-Doll-Research (SDR) and Timur-Coates models, enhancing the accuracy of permeability predictions under different cooling conditions. High temperatures slightly reduce the fractal dimension of the pore structure, which negatively correlates with permeability. As temperature rises, pore coalescence and crack propagation increase, significantly altering permeability. DEM simulations show that cracks are mainly influenced by tensile stresses and thermal expansion and contraction stresses. Higher heating temperatures cause more extensive cracks, while crack contributions decrease during cooling at 600 °C. Thermal damage creates additional energy release paths, increasing local thermal resistance and hindering heat transfer. Finally, thermal cycling results in a more directional crack distribution and a notable decrease in contact angles at 600 °C, indicating microstructure rearrangement.

This study aims to analyze the influence of lateral stress coefficient k and anisotropy on the dynamic response and failure characteristics of deep jointed rock masses under contour blasting. Using phyllite as the test material, local contour blasting-unloading experiments are conducted under biaxial conditions. The analysis focuses on the failure characteristics of the tunnel surrounding rock under different k and joint orientations. Results indicate that when k=1, blasting-induced fractures preferentially propagate along the joint direction. As k decreases, these fractures can deviate from the joint direction and extend toward zones of higher local stress. This tendency is particularly evident when the high-stress direction aligns with the tunnel contour, enabling fracture penetration through closely spaced contour blastholes. During the unloading, blasting-induced circumferential fractures undergo further shear failure, while radial fractures are compacted and closed. The failure of tunnel sidewalls is primarily controlled by circumferential stress concentration and anisotropic compressive strength, whereas failure at the tunnel crown is mainly governed by blasting stresses and the anisotropic tensile strength of the rock mass. This study proposes conditions for the initiation and coalescence of blasting-induced fractures, providing a theoretical basis for contour blasting and support design in anisotropic rock masses.

Stress represents a critical determinant of dynamic hazards in underground coal mining operations. Heterogeneous geological features substantially influence stress distribution and magnitude throughout mining environments. To investigate the mechanical evolution and failure mechanisms of heterogeneous stratified composite coal-rock (CCR) under mining-induced stresses, three-point bending tests (TPBT) and numerical simulations are conducted on CCR specimens with varying homogeneity indices. Results show a significant positive correlation between CCR fracture strength and the homogeneity index (φ). Higher φ values are associated with more uniform displacement discontinuity zones during the fracturing process. Initial loading is observed to induce compressive strain at the upper coal-rock interface (UI), while tensile strain predominated at both the lower interface (LI) and boundary (LB). Interface strain magnitudes followed the pattern LB>LI>UI, with stability inversely proportional to strain intensity. As φ increases, interfacial stability is reduced, damage severity is amplified, and the critical strain energy release rate is elevated. These variations are primarily governed by the homogeneity-dependent redistribution of particle zones and the downward migration of resistant interfaces. These findings enhance our understanding of fracture propagation in heterogeneous CCR under mining stresses, thereby contributing to improved hazard forecasting and control strategies in coal mine composite roof systems.

The complex stress environment during underground space reuse in deep mines often leads to significant instability in the surrounding rock-lining support structure of roadways. To address this, a multi-component carbon-reinforced lining material (CGNC) was developed to improve the mechanical properties and self-sensing capabilities of the surrounding rock-lining support structure, enabling precise identification of precursor information related to surrounding rock-lining instability and failure. In this study, the failure precursor characteristics of the sample are obtained by analyzing the CGNC acoustic emission parameters, resistivity, and full-field main strain during the loading process. By combining the b-value, failure precursor resistivity, and strain monitoring, the precursor information is quantitatively characterized. Finally, a response mechanism for precursor information, based on the integration of “force-acoustic-electricity-graph” is established. The results are as follows: 1) The optimal content of carbon-based materials is 0.2% graphene (GPE), 0.3% nano-carbon black (NCB), and 0.15% carbon nanotube (CNT), which results in an 86.7% increase in the sample’s strength. The yield stress can serve as the “failure precursor” for the sample’s instability. As the content increases, the “failure precursor” is delayed accordingly. 2) As the stress level approaches the yield stress, the b-value decreases sharply, acoustic emission energy increases significantly, and the resistivity and main strain curves nearly synchronously reach the “inflection point”, which serves as the precursor to sample failure. 3) With increasing carbon-based material content, the synergistic effect of the three materials causes the failure mode of the sample to evolve from uniform single cracking and tensile failure to large-scale fracture and multi-crack tensile-shear composite failure, fundamentally explaining the modification mechanism of carbon-based materials in cement-based composites. These findings provide theoretical support for the instability failure mechanism and early warning system of CGNC.

Deep tunnels are often subjected to the combined effects of high geostress and dynamic disturbances, which results in more complex mechanical properties and failure modes compared to shallow tunnels. To study the failure characteristics of tunnel surrounding rock under static-dynamic coupled loading, dynamic tests were conducted using a typical split Hopkinson pressure bar (SHPB) apparatus at different strain rates. The fracture process was recorded using a high-speed camera, and the surrounding rock’s strain field evolution law was analyzed using digital image correlation (DIC) technology. Moreover, a series of numerical simulations under static-dynamic coupled effects were performed using the LS-DYNA software. The results indicate that as the strain rate increases, the main failure mode of the tunnel shifts from tensile failure to shear failure. Lateral pressure significantly suppresses the width and length expansion of cracks, while axial pressure promotes crack propagation, leading to an earlier crack initiation time and triggering more secondary cracks. The study also reveals that the lateral pressure coefficient (k) has an obvious inhibition on the tunnel damage process. Finally, through the analysis of the dynamic stress concentration factor (DSCF), it is found that the existence of confining pressure affects the stress concentration distribution of surrounding rock. The findings provide theoretical support for a deeper understanding of tunnel failure mechanisms and the optimization of tunnel design.

To analyse the collapse mode of the surrounding rock when a tunnel is excavated in a karst region, a scaled model test based on particle image velocimetry (PIV) is designed. The mix ratios of similar materials for different surrounding rock grades are determined via material testing. PIV is used to analyse the images of the surrounding rock deformation captured by a high-definition digital camera during the model experiment. Based on the displacement and velocity diagrams from the model experiment, the range and shape of the excavation-induced collapse of surrounding rock between the karst cave and the tunnel are obtained. Furthermore, the numerical simulation and upper bound theorem are employed to validate the results obtained from the model experiment. The good agreement of the surrounding rock collapse ranges among the model test, numerical simulation and theoretical calculation, showing that the model experiment results presented here is valid.

The evolution law of roadway plastic zone under three-dimensional stress field is of great significance to roadway stability control. The strength criterion is the basis for judging the surrounding rock failure. According to the rock energy theory, the energy strength criterion is established. Based on energy strength criterion and considering the roadway axial stress, the boundary equation of roadway plastic zone under three-dimensional stress field is derived. The results show that the distortion energy required for rock failure is positively correlated with confining pressure. The energy strength criterion can describe the strength characteristics of rock well and reflect the Lode angle effect and hydrostatic pressure effect. The plastic zone shape is mainly determined by the lateral pressure coefficient λ. When λ gradually increases, the plastic zone shape evolution shows ‘circular→elliptical→butterfly-shaped’. Axial stress mainly affects plastic zone size. The closer the axial stress is to horizontal stress, the smaller the plastic zone size. When the stress environment and roadway size are constant, the main factors affecting plastic zone expansion are the uniaxial compressive strength of coal-rock mass of roadway and the material parameter in the energy strength criterion. The plastic zone size decreases with the increase of the two.

Bedding structures significantly influence rock mass deformation and failure, challenging engineering stability. This study aimed to investigate the fracture mechanisms of layered rock masses by examining the effects of bedding and prefabricated fissure inclination angles on the mechanical behavior of layered Brazilian disc specimens. Layered rock-like Brazilian disc specimens were prepared by combining sand 3D printing technology with cement slurry as a bonding agent, enabling precise control of bedding features. Uniaxial compression tests, with a loading rate of 0.3 mm/min, coupled with digital image correlation (DIC) technology, were conducted to capture load-displacement curves and crack propagation processes, with two schemes designed to explore varying prefabricated fissure inclination angles (α) and bedding inclination angles (β). Additionally, the discrete element method (DEM) using particle flow code (PFC) with parallel bond (PB) and smooth-joint (SJ) models was employed for numerical simulation, with mesoscopic parameters calibrated against experimental data. The results showed that both α and β significantly affected crack propagation and failure modes: Increasing α led to a gradual increase in peak strength, with cracks initiating from fissure tips and propagating toward loading points; Increasing β caused the failure mode to transition from vertical splitting to bedding-controlled fracture, with peak strength first decreasing, and then increasing. PFC simulations effectively reproduced experimental load−displacement curves and crack morphologies, confirming numerical reliability. This study demonstrates that sand 3D printing with cement bonding is viable for fabricating layered rock-like specimens, and the combined experimental and numerical results provide insights into layered rock fracture mechanisms, offering references for understanding bedding and prefabricated fissure influences on rock mechanical behavior.

To underscore the overestimation of the ground bearing capacity by continuum-based numerical or analytical methods, the discrete element method (DEM), which may capture the microscopic characteristics of soil with graded particles, is used to study the ultimate bearing capacity of the ground (p_u). In this work, the rolling resistance linear model of contact is implemented by the DEM for the soil, so the ultimate bearing capacity of the ground can be predicted. During the loading process in the DEM test, the development of a failure zone (or shear band) in the ground can be observed. Numerical experiments reveal that there is a certain negative linear relationship between the footing’s ultimate rotation angle (α_u) and p_u, offering a novel perspective on the study of p_u. Due to the asymmetry of the DEM ground, a new modification factor η_p is defined for the ultimate bearing capacity. It is found that particularly for soils with a large mean particle size, narrow gradation or poor continuity of the particles, the effect of particle gradation characteristics on the ultimate bearing capacity should be appropriately evaluated.

Microwave fracturing is a promising technique for facilitating the efficient exploitation of deep earth resources while reducing energy consumption and cutter wear during mechanical excavation. In this study, the thermal properties of basalt under six power levels are investigated and the mechanism of microwave fracturing is elucidated through real-time monitoring and microstructural analysis. The results show that the failure modes of basalt can be categorized into high-temperature melting failure (>300 °C) and low-temperature burst failure (<200 °C). High-power microwave irradiation not only altered the failure mode but also modified the relationship between temperature rise and time. The temperature distribution exhibits a wave pattern, making it more prone to inducing transverse tensile cracks. Dehydration of basalt is triggered when the temperature exceeds 200 °C, which subsequently promotes the initiation of macroscopic cracks. Microscopically, microwave fracturing is mainly driven by thermal stresses, while steam pressure, especially under high-power conditions, plays a dominant role in the fracturing process. These results are anticipated to provide necessary theoretical and technical support for the efficient exploitation of deep earth resources.

Plant roots serve as a natural reinforcement method with the potential to significantly enhance slope stability. In engineering practice, roots can function synergistically with geosynthetics, reducing the reliance on artificial materials. Based on a three-dimensional (3D) rotational failure mechanism, this study proposes a novel framework to evaluate the influence of plant roots on the stability of geosynthetic-reinforced slopes. By integrating the hydrological effects of transpiration and the mechanical composite action of root – soil interaction, the reinforcing capacity of uniform root systems is comprehensively assessed. The required dimensionless reinforcement strength at the limit failure state is derived using the functional balance equation. The validity of the proposed method is confirmed through comparisons with existing two-dimensional (2D) solutions for vegetated slopes and 3D solutions for non-vegetated reinforced slopes. Furthermore, various parameter plots are provided to facilitate design analysis. The results indicate that accounting for 3D spatial effects and plant root reinforcement significantly reduces the required reinforcement strength, thereby lowering construction costs and enhancing overall slope safety.

The Western Dongting Lake area, a biodiversity hotspot under traditional farming, has long suffered heavy metal pollution. In this study, the concentrations of As, Cd, Cr, Hg, and Pb in agricultural soils were determined and ecological risks were evaluated using both the hazard quotient(HQ) model and the probabilistic ecological risk assessment(PERA) model. The results showed that HQ suggested slight or negligible risks, whereas PERA indicated consistently high and unacceptable risks. This discrepancy arose because HQ criteria are derived from human health thresholds and provide only deterministic estimates, whereas PERA incorporates species-specific predicted no-effect concentration(P_NEC), environmental variability, and uncertainty, thereby providing more precise and site-specific risk assessments and assigning probabilities. By applying a tiered PERA model, our study highlights its novelty and superiority in ecological risk characterization, providing critical guidance for soil management and ecological protection in contaminated farmlands.

The accuracy of wheel-rail rolling contact force is of great significance for vehicle dynamics simulation. A wheel-rail rolling contact behavior model considering wheelset yaw is proposed. The NORM algorithm is adopted to solve the wheel-rail normal contact problem. The extended creep force model (ECF) is used for the tangential contact problem, which considers different interfacial conditions, temperature in the contact area, and the elastoplastic behavior of the third body. A fatigue life prediction framework based on the critical plane method is introduced to evaluate the contact fatigue damage under the coupled influence of yaw angle and interfacial conditions. The effects of wheel yaw angle on the contact pressure and wheel-rail rolling contact fatigue life under dry and wet conditions are investigated. The results show that under both dry and wet conditions, increasing yaw angle leads to an increase in creepage, expansion of the sliding area, enhancement of creep force, and a simultaneous increase in the contact area temperature, thereby causing an increase in the fatigue parameter (FP). The wheel-rail rolling contact life with yaw angle is shortened compared to that without yaw, and the life decay rate under wet condition is slower than that under dry condition.

The sensorless control of surface-mounted permanent magnet synchronous motor (SPMSM) usually uses quadrature phase-locked loop (QPLL) to extract the phase information of the back electromotive force to realize the rotor angle estimation. However, the traditional QPLL has a convergence deviation of 180° when the motor is reversed, and the angle estimation error is obvious when the motor is accelerated and decelerated. To solve these problems, an enhanced QPLL (EQPLL) with polarity correction and high precision angle feedforward compensation is proposed. Firstly, the traditional phase discriminator is improved based on the two-phase stationary coordinate system, and the polarity correction function is designed by the error component of the improved phase discriminator to realize the non-convergent deviation angle estimation under the forward and reverse switching conditions of the motor. In addition, the error component of the improved phase discriminator is used as the feedforward compensation signal, and the enhanced generalized integrator is used to filter it, so as to realize the angle error compensation with low delay and low noise. Finally, the proposed scheme is verified by experiment on the motor platform, and compared with the existing scheme. The experimental results show that the proposed scheme can realize the polarity correction and angle error elimination, and at the same time, the noise mean square error is reduced by 24.33% compared with the existing angle feedforward compensation scheme.