Search Results (805)

The Mw 7.1 earthquake occurred in Wushi County on 22 January 2024, representing the largest earthquake in the southern Tianshan Orogen for more than a century. Together with two subsequent strong aftershocks, this sequence allows us to examine the geometry of the complex fault system and interactions of seismic and aseismic slip. Using InSAR observations, we resolved the coseismic and postseismic deformation to constrain the slip distributions associated with the earthquake sequence. The results show that the mainshock ruptured a northwest-dipping fault, with coseismic slip mainly concentrated at depths of 10–30 km and peaking at approximately 2.7 m near 16 km, releasing a geodetic moment of 4.9 × 10¹⁹ N·m (Mw 7.1). The 2024 Mw 5.7 aftershock ruptured a surface-reaching fault with a peak slip of approximately 1 m at approximately 2 km depth, whereas the 2025 Mw 5.8 aftershock ruptured a nearby blind fault at depths of 5–10 km. Afterslip during the first six months occurred predominantly on the mainshock fault, and was largely complementary to the large coseismic slip zone. The cumulative geodetic moment released by the ~six-month afterslip was estimated to be 5 × 10¹⁸ N·m, equivalent to approximately 10.2% of the mainshock moment. The Coulomb stress analysis shows that the mainshock produced positive stress changes of approximately 1.6 bar and approximately 2.6 bar at the hypocenters of the Mw 5.7 and Mw 5.8 aftershocks, respectively, bringing both faults closer to failure. In addition, positive stress changes induced by postseismic afterslip on the Mw 5.8 fault indicate that time-dependent stress redistribution further promoted its failure. These results reveal the spatial and temporal partitioning of seismic and aseismic slip within a multi-fault system and highlight the importance of integrating coseismic rupture, postseismic afterslip, and stress-transfer processes to better assess postseismic seismic hazard in continental thrust regions. Full article

Understanding the anisotropic mechanical behavior and pore–fracture structure (PFS) evolution of bedded coal under mining disturbance is critical for gas extraction and hazard prevention in deep coal mining. This study employed low-field nuclear magnetic resonance (NMR) and fractal analysis to characterize the PFS of water-saturated coal samples with bedding angles of 0°, 30°, 45°, 60°, and 90°. The pore system was classified into adsorption and seepage pores according to pore size distribution. Real-time triaxial NMR tests were further conducted to reveal the coupled evolution of mechanical responses and PFS under different bedding orientations. Results show that bedding inclination controls pore distribution, connectivity, and structural complexity, while influencing coal strength, deformation, and failure through stress redistribution and bedding-plane activation. The mechanical response and PFS evolution exhibit strong anisotropic coupling during loading. A fractional-order porosity model was established by incorporating bedding orientation, anisotropy, and stress memory based on pore geometry and stress decomposition. Model verification confirms its effectiveness in describing anisotropic porosity and PFS evolution under varying bedding angles. This study provides theoretical support for permeability prediction, stability assessment, and hazard control in deep-bedded coal seams. Full article

The shear behavior of corrugated steel web (CSW) composite girders near intermediate supports differs fundamentally from that of conventional beam segments due to the rigid restraint of concrete cross-beams, yet current design codes incorrectly assume the CSWs resist the entire shear force. This paper presents a refined analytical method, based on a three-beam composite model, that explicitly accounts for the cross-beam constraint effect. By assuming a quadratic parabolic distribution of the additional shear-flow intensity along the constraint zone, a closed-form expression for the effective shear force carried by the CSWs is derived. The proposed method is validated against three-dimensional finite element (FE) simulations and existing experimental data, and further corroborated by a parametric study covering varying structural configurations. The results confirm a shear redistribution mechanism characterized by “CSWs unloading and flange sharing.” At the section nearest to the cross-beam, the CSWs actually carry only 65.41% of the total shear force, while the flanges share approximately 35%. In contrast, the conventional code method, which neglects flange shear contribution, severely overestimates CSWs’ shear stress, producing an error as high as 35.29% at the section adjacent to the cross-beam. These findings demonstrate that the cross-beam constraint must be considered in shear design, especially near supports, and the proposed method offers a rational and accurate alternative to existing code provisions. Full article

Footwear geometry plays an important role in determining mechanical performance, plantar load distribution, comfort, and foot stability during gait. Understanding how constructive design parameters influence foot biomechanics is essential for developing footwear that improves comfort while reducing excessive mechanical loading. Although various finite element studies have investigated insole and outsole design, midsole materials, and plantar pressure redistribution, comparatively little attention has been paid to the influence of upper construction parameters, particularly vamp opening configuration, on the biomechanical behaviour of feet and footwear. This study investigates how the opening amplitude of the vamp affects the biomechanical response of three constructive variants—medium (M1), wide (M2), and narrow (M3) vamp openings—developed on a common shoe last derived from anthropometric data. Finite element analysis was conducted using ANSYS 17.2, with 3D models built in Delcam Crispin ShoeMaker Pro 2015 R2 for the three loading scenarios. Total deformation and von Mises stress were extracted as primary output parameters for both the foot and footwear. The results indicate that wider vamp openings increase structural flexibility, with M2 recording the highest total deformation across multiple scenarios, whereas narrower openings generate elevated stress concentrations, particularly in loading scenario 2. The medium vamp opening (M1) demonstrated the most favourable stress distribution overall, with a maximum stress of 1.838 Megapascals (MPa). Validation against experimental plantar pressure data confirmed that loading scenario 3 follows the same plantar pressure distribution trend as in the biomechanical study. The results confirm finite element analysis as an effective computational tool for footwear design evaluation and indicate that vamp amplitude should be considered alongside material selection and geometry as a key variable influencing comfort, fit, and structural performance. Full article

Lined rock caverns offer a promising option for underground hydrogen, helping to mitigate renewable intermittency and enhance system stability. Considering the geological characteristics of hard rock formations in Southern Ontario, Canada, this study establishes a thermo–gas–mechanical coupled framework that incorporates hydrogen mass and energy evolution in the cavern, gas–wall convective heat exchange, dynamic cavern-volume feedback, and the deformation behaviour of the sealing layer, concrete lining, and surrounding rock. The influences of cavern geometry, sealing material, and in situ stress on the short–term thermodynamic and mechanical responses are further examined. The results show that hydrogen temperature and pressure exhibit clear stage–dependent evolution during the charging–storage–discharging cycle. The comparison between the first and 20th operating cycles indicates that repeated operation mainly causes a moderate adjustment of the cyclic thermal state and temperature–pressure baseline, without changing the overall stage–dependent response pattern. During charging, temperature and pressure increase simultaneously; during storage, both gradually decrease as thermal energy is transferred to the cavern wall; and during discharging, expansion causes pronounced cooling and depressurization, followed by gradual recovery driven by heat transfer from the surrounding rock. Cavern geometry significantly affects stress redistribution around the cavern. The circular cavern shows a relatively uniform stress distribution, whereas the arched cavern is more prone to local stress concentration near the sidewall–floor transition zone. The sealing material mainly influences gas temperature fluctuations through its thermal conductivity. The fibre–reinforced plastic (FRP) sealing layer amplifies thermal fluctuations during cyclic operation, whereas the steel sealing layer promotes heat dissipation through the lining and surrounding rock, thereby moderating cavern–gas temperature variations. In situ stress difference further controls the directional distribution of stresses around the cavern. As the minimum horizontal principal stress increases, compressive stress concentration at the crown and invert becomes stronger, while relative stress release occurs near the sidewalls. These findings provide a thermo–mechanical basis for preliminary cavern–geometry design, comparison of sealing–layer thermal performance, and assessment of in situ stress adaptability for lined rock cavern hydrogen storage in Southern Ontario. Full article

Residual stresses generated during laser powder bed fusion (LPBF) can cause substantial distortion in slender structures, compromising dimensional accuracy and structural reliability. This study tests the hypothesis that, under identical nominal processing conditions, geometry-dependent stiffness and constraint govern how the evolving thermally induced stress field is redistributed and manifested as warpage after support removal. Bridge-type TA15 titanium alloy cantilever specimens with different spans, thicknesses, and support densities were fabricated by LPBF, and their post-cut warpage was quantified by three-dimensional scanning. A coupled thermo-mechanical finite element model was validated against the measured deformation profiles and subsequently used to examine simulated stress evolution during deposition and redistribution after support removal. Cantilevers with different spans approached similarly high simulated surface tensile-stress plateaus in the constrained as-built state but exhibited markedly different measured warpage after cutting, showing that the as-built stress magnitude alone does not reliably rank post-release deformation. Increasing span reduced global flexural resistance and enlarged the effective bending arm, whereas increasing thickness enhanced flexural rigidity and suppressed curvature even when relatively high localized stress was retained. With the total support volume held constant, changing support density altered the system-level constraint through the combined effects of support-leg stiffness, support spacing, local thermal and mechanical response, and deformation compatibility. Together, these results provide an experimentally supported process-structure interpretation of LPBF cantilever distortion across controlled variations in span, thickness, and support distribution. Full article

Global food systems must balance productivity with environmental sustainability amid climate change, geopolitical shocks, and unevenly distributed natural resources. This study introduces the Food Supply Sustainability Index (FSSI), a transparent, composite measure of the sustainability of a nation’s food production including international trade, and future climate-driven trade dynamics, with a distance-to-target method. Using FAO and IFPRI data, the FSSI categorises countries into five sustainability classes across three pillars: carbon footprint, soil degradation, and water stress. The results show high-income countries produce food less sustainably, while low-income countries do so more sustainably yet are more vulnerable to climate change and trade disruptions. The FSSI therefore recognises that trade redistributes rather than removes environmental risk, creating a more evenly distributed yet persistent global vulnerability to shocks. Under future climate scenarios, the index identifies that sustainability worsens in poorer regions, especially Sub-Saharan Africa, exposing countries to food insecurity. By combining multiple environmental dimensions into a single metric, the FSSI enables countries to benchmark sustainability performance and identify priority areas for intervention. The FSSI supports policies such as aligning imports with sustainability criteria, diversifying suppliers toward lower-impact origins, and supporting sustainable intensification in low-income settings. The FSSI provides a replicable, policy-relevant tool to assess, compare, and communicate global food system sustainability. Full article

A novel assembled integral multi-ribbed composite floor system consisting of precast panels and a cast in situ topping has previously been validated through full-scale one-way and two-way slab experiments. Although the global load capacity of the system was initially verified, the experiments reveal that the concrete-to-concrete interfacial behavior between the precast panel and the cast in situ topping is a critical factor governing internal force redistribution and its post-cracking performance. To uncover the governing interfacial mechanism, this study develops a refined three-dimensional nonlinear finite element model using a coupled cohesive–frictional interface interaction, where a surface-based cohesive interaction captures the initial interfacial debonding and a penalty-based Coulomb friction model describes the subsequent shear-slip behavior. The model reproduces the cracking patterns, load-deflection relationship, and failure modes, with the relative error of load capacity, initial stiffness and crack load all less than 15%. Parametric analyses further indicate that the interfacial shear-transfer mechanism governs post-cracking stress redistribution across the multi-ribbed section, preventing premature delamination and ensuring efficient mobilization of the section’s flexural resistance. To effectively restrain this interfacial slip, an improved shear-key configuration is proposed to activate an enhanced mechanical interlocking mechanism. Numerical results confirm that the improved configuration effectively suppresses macro-sliding and redistributes local stress concentrations, thereby enhancing the structural integrity and flexural efficiency of precast composite floor systems. Full article

Child-well stimulation design has become a central challenge in mature unconventional reservoirs, where infill wells are commonly completed in reservoirs that have already been modified by parent-well production. Prior depletion changes pore pressure, stress distribution, and fracture-propagation pathways, causing child-well treatments to behave differently from parent-well completions. As a result, increasing fluid volume, proppant loading, stage density, or pump rate does not necessarily produce proportional gains in recovery. This review synthesizes the comprehensive literature on child-well stimulation intensity with emphasis on well performance, fracture-driven interactions, pad-scale economics, diagnostics, and resource-use considerations. The analysis shows that the production response is highly conditional: larger treatments can enhance reservoir contact when fractures access underdrained rock; however they may lose effectiveness when depletion-induced stress changes redirect fracture growth toward parent-well drainage areas or pre-existing fracture networks. In such cases, higher nominal intensity can increase interwell communication, reduce completion efficiency, impair parent-well performance, and weaken pad-level economic value. A key outcome of this review is the distinction between nominal stimulation intensity, represented by the treatment pumped, and effective stimulation intensity, represented by the fraction of that treatment that creates incremental productive fracture area. This distinction reframes child-well optimization from a treatment-size problem to a depletion-aware fracture-placement problem. Diagnostics, coupled modeling, production analysis, and mitigation strategies are therefore necessary to determine whether added stimulation intensity improves recovery or primarily redistributes production within the pad. From an economic perspective, the pad rather than the individual child well is the correct unit for evaluating stimulation-intensity decisions, since pad-level net present value integrates incremental child-well recovery, parent-well degradation, protection costs, spacing effects, and completion capital. Produced-water reuse and lifecycle emission benchmarking represent practical tools for reducing the environmental footprint of child-well development programs while simultaneously lowering freshwater demand and disposal volumes. These economic and environmental dimensions are inseparable from the technical optimization of stimulation intensity and are addressed explicitly in this review. This review concludes that child-well stimulation intensity should be optimized within a pad-scale framework that integrates depletion state, spacing, landing-zone selection, parent-well management, and long-term value rather than being uniformly maximized. Full article

Ultra-supercritical (USC) steam turbines combine severe steam conditions with increasingly frequent start-up, shutdown, and load-following operations. Their main steam valves must preserve pressure boundary integrity, sealing, and rapid actuation while non-uniform heating, creep, cyclic plasticity, oxidation, wear, and contact redistribution alter component geometry. However, the relevant evidence remains fragmented across alloy development, component thermo-mechanics, valve aerodynamics, and lifetime monitoring. This short, mechanism-oriented review integrates these domains through a material structure–function framework in which deformation relative to assembly clearance governs jamming risk. It synthesizes evidence on heat-resistant body and surface materials, 9–12% Cr steel stability, weldability and repair sensitivity, and cold, warm, and hot start-up histories. It also evaluates creep–fatigue interaction, contact, flow-induced vibration, multi-physics modeling, validation, uncertainty, monitoring, and digital twins. The synthesis shows that neither peak equivalent stress nor steady-state temperature alone can establish functional reliability. Credible assessment requires temperature-dependent material data, realistic steam-side heat transfer, cyclic constitutive behavior, initial and residual clearances, manufacturing and assembly tolerances, state-dependent friction, uncertainty analysis, and corroborating plant or inspection evidence. The most consequential research needs are valve-level validation datasets, thermal contact testing, function-oriented life criteria, and uncertainty-aware digital twins that jointly inform materials, geometry, and transient operation. Full article

Low-slenderness-ratio, flat-ended autonomous underwater vehicles must balance hydrodynamic resistance against internal volume retention, yet classical slender-body criteria do not fully represent their coupled forebody wake response. A generalized Myring forebody was assessed for an AUV with L = 0.8 m, D = 0.2 m, and L/D = 4.0 using 53 steady three-dimensional Reynolds averaged Navier-Stokes simulations with the shear stress transport k-ω model. Gaussian process regression and the non-dominated sorting genetic algorithm II (NSGA-II) were used only for candidate-region screening; production grid direct CFD samples were used to determine nondominance. Strict fold-wise leave-one-out cross-validation gave ${\mathrm{Q}}^2$ = 0.173 globally and RMSE = 0.001399 and ${\mathrm{Q}}^2$ = 0.683 in the predefined 18-sample decision region, indicating local screening utility rather than global surrogate validation. The direct CFD audit identified 13 globally and seven locally nondominated samples; both previously selected test configurations were dominated after CFD back-substitution. Their three grid drag sequences were monotonic but non-asymptotic. Pressure drag comprised 75.88–79.20% of total drag. However, the reduction in the low-drag test configuration relative to the baseline arose mainly from a lower viscous contribution; axial pressure fields therefore indicate redistribution rather than exclusive drag-reduction causation. Paired CFD samples showed that the sign of the drag responded to N reversal between the two sampled ${\mathrm{L}}_{\mathrm{nose}}$ values, whereas analytical volume increased with N in both pairs. The results reveal a discrete, configuration-dependent drag volume trade-off and local N-${\mathrm{L}}_{\mathrm{nose}}$ coupling. The rectangular regions are sampling envelopes rather than validated optimum windows, and the conclusions are restricted to steady, deeply submerged, smooth-wall bare-hull conditions. Full article

Single-story unreinforced masonry rural houses along the Tanlu Earthquake Belt in Anhui Province are generally constructed without ring beams and tie columns, resulting in poor structural integrity and low seismic performance. This paper proposes a convenient single-sided High-Ductility Concrete Strip (HDCS) retrofitting method. Two 1:2 scaled test specimens, namely the unretrofitted model M1 and HDCS single-side retrofitted model M2, were fabricated for shaking table tests. Systematic analyses were carried out based on white noise sweep tests, failure modes, acceleration responses and inter-story displacement responses. The test results show that HDCS possesses excellent tensile capacity, which forms continuous confinement at wall joints and openings to boost structural stiffness and greatly restrain post-seismic stiffness degradation, as well as achieve more uniform structural deformation distribution. Under strong seismic excitations, the unretrofitted model suffers severe damage, including penetrating diagonal shear cracks and separation between gable walls and lower walls. In contrast, damage of the retrofitted model is concentrated within the HDCS overlay, realizing damage redistribution and preventing brittle failure of the main masonry. HDCS stabilizes the distribution of acceleration amplification factors and restrains wall rocking and stress concentration around openings. Although single-sided strengthening induces slight out-of-plane effects, its adverse influence is acceptable. Full article

Climate change and increasing instability in coastal marine environments have intensified stressors such as elevated temperature, hypoxia, salinity variation, and pollutant exposure, posing major challenges to the survival, health, and culture performance of bivalves. As economically important aquaculture species and key components of coastal ecosystems, bivalves are highly sensitive to environmental fluctuations, making their metabolic responses highly relevant to both physiological adaptation and aquaculture sustainability. Increasing evidence indicates that metabolic remodeling is an important adaptive strategy supporting bivalve tolerance to environmental stress, with amino acid metabolic remodeling emerging as one of its most sensitive and functionally important components. This review summarizes the major response patterns, key pathways, and potential regulatory mechanisms of amino acid metabolism in bivalves under different stress conditions. Different environmental stressors induce distinct yet integrated shifts in amino acid metabolism, including enhanced catabolism, carbon–nitrogen redistribution, osmotic regulation, and antioxidant defense, thereby supporting energy homeostasis and physiological stress tolerance in bivalves. By highlighting amino acid metabolic remodeling as a central mechanism of bivalve adaptation to environmental stress, this review provides insights into adaptive responses, metabolite-based indicators for monitoring aquaculture environments and bivalve health, and management strategies for improving resilience in bivalve aquaculture. Full article

Carbon fiber-reinforced polymer (CFRP) composites are widely used for strengthening concrete structures, but the bond behavior of CFRP–concrete interfaces in cracked concrete remains insufficiently understood. This study investigates the effect of saw-cut notch depth on the interfacial bond behavior between CFRP sheets and concrete through double-shear tests. Twelve specimens were prepared with saw-cut notch depths of 0, 10, 20, and 30 mm, where the crack width of the cracked specimens was fixed at 1 mm. The ultimate bearing capacity, CFRP strain transfer behavior, load-relative displacement response, interfacial bond shear stress distribution, and local bond–slip relationship were systematically analyzed. The results show that increasing saw-cut notch depth weakens both the bearing capacity and deformation capacity of the CFRP–concrete interface. Compared with the uncracked specimens, the average ultimate load decreased by approximately 5.0%, 9.2%, and 14.7% for crack depths of 10 mm, 20 mm and 30 mm. Deeper cracks promoted earlier expansion of the CFRP strain transfer region toward the free end and accelerated the development of interfacial relative displacement. The shear stress distribution further indicated that the saw-cut notch altered the interfacial stress transfer path and promoted earlier redistribution of bond shear stress along the bonded length. Based on the experimental results, an empirical normalized curve-shape function was developed to describe the effects of saw-cut notch depth and distance from the notch on the normalized local bond–slip response. Within the present dataset, the calculated curves showed general consistency with the experimental normalized curve trends, particularly in the post-peak descending branch. Full article

Background: Minor phytocannabinoids engage CB₁ and CB₂ receptors, as well as broader receptors and ion-channel targets. However, fragmented evidence limits translation into central nervous system (CNS) therapeutics. This review introduces pharmacological switching, defined as a dose-, state-, or model-dependent shift in the dominant determinant of a compound’s net effect that reverses the direction, rather than merely the magnitude, of that effect on a defined functional endpoint, as a framework for compound–indication matching. Unlike biased agonism, which redistributes downstream coupling without reversing direction, switching requires directional reversal between or within receptor systems. Methods: This narrative review integrates receptor pharmacology, preclinical CNS disease-model data, early-phase clinical evidence, and pharmacokinetics identified through a structured literature search. Results: Three mechanistic axes recurred: PPARγ/CB₂/Nrf2-linked neuroinflammatory modulation; TRP/GABA_A/5-HT₁A-linked control of neuronal excitability; and low-efficacy CB₁ antagonism with 5-HT₁A potentiation. Their expression was context-dependent: tetrahydrocannabivarin is reported to shift from CB₁ antagonism toward partial agonism as receptor occupancy rises, cannabidiolic acid shows stress-conditional anxiolytic and antiemetic activity, and cannabigerolic acid displays seizure-model-dependent bidirectionality. No instance yet meets all five defining criteria; each is graded provisional or proposed pending systematic testing. Human evidence remains limited: inconclusive cannabidivarin efficacy in epilepsy and neuropathic pain, proof-of-mechanism neuroimaging in autism, and early tetrahydrocannabivarin safety data. Conclusions: Minor phytocannabinoids are pharmacologically diverse but clinically underdeveloped. A tiered, biomarker-guided framework is proposed to match compound–indication pairs to the doses, formulations, and subgroups most likely to express their therapeutic pharmacology. Full article