Search Results (5,130)

Accurate prediction of pile base resistance is essential for the safe and economical design of deep foundations, particularly in soft soils where load-transfer mechanisms are highly nonlinear and uncertain. This study develops a comparative, probabilistic, and interpretable machine learning framework for predicting pile unit base resistance using five input variables: applied load, settlement, effective pile length, axial stiffness, and SPT value. A Gaussian Process Regression model with an automatic relevance determination (ARD) Exponential kernel achieved the best performance, with RMSE = 262.11 kPa, R² = 0.943 on an independent test set, and 95% prediction intervals with 96.46% coverage. Beyond record-level evaluation, a leave-one-pile-out validation (the first grouped validation applied to this database) showed harder generalization to entirely unseen piles, driven mainly by a per-pile level offset rather than shape mismatch (within-pile correlation = 0.975). A sequential next-stage scheme, calibrating this level from a pile’s early loading stages, then predicted its remaining segments with consistently strong agreement (Willmott’s d = 0.76–0.83), supporting practical extension of partial load tests. Interpretability was assessed using ARD, SHAP, permutation/ablation importance, and partial dependence/accumulated local effects analysis, identifying settlement as the dominant predictor. The framework combines accuracy, calibrated uncertainty, interpretability, and validated segment-level extrapolation for reliability-oriented pile assessment. Full article

Geopolymers represent a promising material platform for extrusion-based 3D printing; however, current research remains largely focused on mix design, rheology, printability, buildability, and the relationship between process parameters and the resulting microstructure. This article therefore compares the behaviour of two 3D-printed geopolymer composite truss beams with reference cementitious composite beams developed within the 3D STAR project. The geopolymer elements, 2932 mm long, were designed for the same material volume and target geometry as the reference CC element; however, because of mixture spreading, they reached cross-sections of only approximately 140/250 mm and 170/250 mm. The first beam was printed without setting acceleration, while the second was locally treated with a hot-air gun. In four-point bending, GC-2 was loaded first and reached 22 kN, while GC-1 was loaded second and reached 29 kN; the reference cementitious beams reached 31 and 40 kN. The CC elements failed by rupture of the tensile reinforcement, while the GC elements failed by joint failure followed by deformation and local disintegration of the composite. The study thus shows that the main difference between the two systems lies not only in the achieved load-bearing capacity, but also in stiffness, the shape of the load-displacement diagrams, and the failure mechanism. Full article

Asphalt pavements undergo progressive mechanical changes during service life due to traffic loading, temperature variations, moisture and material ageing. Embedded strain sensors can support in-situ pavement performance monitoring, but their response is strongly affected by experimental variables that must be identified before reliable long-term ageing indicators can be established. This study establishes an in-situ baseline mechanical monitoring framework for asphalt pavements using embedded resistive strain transducers. KM-100HAS sensors were installed in an asphalt test section and evaluated through controlled field campaigns. A 17-point cross-pattern loading procedure was used to validate sensor location and orientation after construction. Load-free monitoring windows were analysed to estimate strain–temperature sensitivity and assess thermal correction of static loading–recovery tests. The results showed that loading position strongly conditions the measured strain response. Passive monitoring indicated that strain–temperature sensitivity depends on both temperature level and sensor location. In the mechanical tests, normalization of the recovery branch and logarithmic fitting over the first 200 s provided a consistent recovery-shape descriptor. The resulting slope, $b_{\mathrm{l}\mathrm{o}\mathrm{g}200}$, showed a strong linear relationship with the recovery percentage after 10 min (R² = 0.855). The proposed workflow provides a standardized baseline protocol for asphalt pavement monitoring and its mechanical evolution. Full article

Spacecraft and launch-vehicle structures require lightweight multipoint monitoring under combined mechanical, thermal, and environmental loads. This study presents an analytical fiber Bragg grating (FBG) sensor-network workflow integrating reference-grating temperature compensation, regional strain assessment, opposite-surface curvature sensing, wavelength-division-multiplexing allocation, and strain-to-shape reconstruction. The deterministic compensation case is used only as a self-consistency check, whereas practical robustness is assessed through 10,000 Monte Carlo trials incorporating packaged-coefficient mismatch, temperature nonuniformity, wavelength noise, strain-transfer variation, drift, and calibration uncertainty. The calibrated estimator achieved a median strain mean absolute error of 1.73 με and a 95th-percentile error of 4.22 με. The defined finite-element benchmarks produced a maximum engine-mount truss strain of 456.2 με under the defined loads and a median full-field panel-reconstruction normalized root-mean-square error of 1.29% for 18 sensing locations with 2 με noise. Conservative WDM analysis yielded 54, 13, and 16 channels for three operating envelopes, and the prescribed random-vibration spectrum produced 6.78 g_rms. These results demonstrate a reproducible numerical proof of concept and define practical limits for compensation, spectral allocation, curvature interpretation, and inverse reconstruction; they do not constitute experimental validation or flight qualification. Full article

The biological fate of lipid-based nanocarriers (LBNs) is shaped at the interface. Whereas core architecture governs cargo loading, protection, and baseline release, surface architecture mediates the carrier’s initial interactions with proteins, cells, extracellular matrices, and tissue barriers, thereby influencing colloidal stability, immune recognition, targeting, biodistribution, barrier transport, and release initiation. Layer-by-layer (LbL) engineering provides a modular strategy for programming this interface through sequentially assembled coatings in which functional components are spatially separated yet mechanistically coordinated. By integrating polymers, biomolecules—including peptides and nucleic acids—and stimuli-responsive materials, LbL systems can decouple functions that are difficult to regulate independently within conventional single-layer or compositionally mixed surface architectures. This review examines recent advances in LbL-engineered LBNs (LbL-LBNs), focusing on how multilayer surface architecture reshapes physicochemical properties, cargo localization and release, biological identity, cellular interactions, and transport across physiological barriers. Particular attention is given to the multilayer interface as a dynamic biointerfacial bridge between a cargo-specific core architecture and the surrounding biological environment, including its capacity for stimuli-responsive switching in pathological microenvironments. The discussion further extends to biomimetic hybrid interfaces and establishes a framework for translating hierarchical surface architectures into reproducible, clinically tractable platforms for precision therapeutic delivery. Full article

This study investigates the influence of diaphragm stiffness on the seismic vulnerability of low-rise masonry buildings using nonlinear static pushover analysis. Two limiting structural idealisations are considered: a rigid-diaphragm model and a conservative model with no effective in-plane diaphragm action. The models are applied to buildings with quasi-rectangular and U-shaped floor plans, and their responses are compared using capacity curves, vulnerability functions, and EMS-98 damage grades. The results show that rigid diaphragms improve the redistribution of seismic forces among load-bearing walls, increase global lateral capacity, reduce displacement demand, and produce a more uniform structural response. In contrast, the absence of effective diaphragm action leads to non-uniform force transfer, increased differential displacements, amplified torsional effects, and substantial reductions in lateral capacity, particularly in the U-shaped building. These effects become more pronounced under higher seismic demand. The results demonstrate that both diaphragm action and floor-plan regularity should be considered explicitly in the seismic assessment of low-rise masonry buildings. Full article

To address the difficulty in accurately evaluating the vertical bearing behavior of prestressed high-strength concrete (PHC) pipe pile-group foundations, this study investigated three single piles and an eight-pile group with a Wang-shaped irregular pile cap through field static loading tests and theoretical analysis. The measured ultimate bearing capacities of single piles D1/D2 and D3 were 7040 and 3000 kN, respectively. For the pile-group foundation, the ultimate bearing state was not reached under the maximum applied load of 15,000 kN, at which the settlement was only 3.52 mm. The pile-head load distribution followed the order corner piles > side piles > inner piles, with corresponding load proportions of approximately 13.9%, 12.9%, and 9.4%. The calibrated API and hyperbolic models predicted the single-pile bearing capacities with errors ranging from 0.23% to 3.40%. The API model better represented the steep-drop portion of the Q-s curve, whereas the hyperbolic model more accurately predicted the initial stiffness and low-load response. For pile-group foundations, the combined equivalent-pier and load-transfer method showed good applicability. The main contribution of this study is to provide field evidence for the vertical bearing and load-transfer behavior of a large-diameter PHC pipe pile group with a Wang-shaped irregular pile cap, extending existing studies that have mainly focused on single piles or conventional symmetric pile groups. The results also provide a quantitative basis for the analysis and design of PHC pipe pile-group foundations in highway bridge engineering. Full article

Driven by the engineering requirement for high acoustic stealth of unmanned underwater vehicles (UUVs), this paper investigates the electromagnetic vibration of an 8-pole, 48-slot, surface-mounted permanent magnet synchronous motor (SPMSM) employed in the propulsion system through multi-physics coupling analysis and experimental testing. First, analytical calculations of electromagnetic force waves are performed based on the Maxwell stress tensor method and the magnetomotive force–permeance method to analyze the spatial orders, temporal orders, and sources of the harmonics. Then, a two-dimensional motor model is established using ANSYS electromagnetic field simulation software to investigate the temporal and spatial characteristics of electromagnetic force waves under both no-load and on-load conditions. Fourier decomposition is applied to obtain the amplitude-frequency characteristics, thereby verifying the correctness of the analytical results. Subsequently, three-dimensional models of the stator core and the complete stator assembly are constructed in the physical field, and their modal frequencies and mode shapes are obtained through simulation. On this basis, harmonic response analysis is conducted by applying electromagnetic force waves to the stator teeth, and vibration simulations are performed in ANSYS Workbench to acquire vibration characteristics. Vibration experiments are then carried out at multiple rotational speeds, and the experimental results are compared with the simulation results to validate the feasibility and accuracy of the finite element modeling approach. Since the measured motor vibration results are influenced not only by electromagnetic excitation forces, but also by various factors such as mechanical structure, instrument installation, and fixture conditions, while the simulation model in this paper inevitably simplifies damping, housing details, inverter control effects, and considers only the effect of radial electromagnetic forces, there exists a certain discrepancy between the simulated and measured motor vibration acceleration results. However, the main vibration trends in the low-frequency range below 800 Hz are basically consistent, particularly at the second and fourth harmonic frequencies, where the vibrations are electromagnetic vibrations caused by radial electromagnetic force waves, with relative errors between the measured and simulated values of 18% and 25%, respectively. This finite element model can be used for preliminary design evaluation of PMSMs and rapid prediction of electromagnetic vibration, providing researchers with a convenient and practical research approach and methodology. Finally, by analyzing factors that may influence motor vibration, this paper proposes design modifications to the stator structure and air-gap width, providing an optimized solution for reducing electromagnetic vibration of the permanent magnet synchronous motor and avoiding resonance. Full article

The scientific problem addressed in this study is how a continuous mechanical architecture can maintain stable lettuce handling while improving treatment-medium access to irregular, overlapping leaf surfaces. We formulate this problem as a morphology-informed design and evaluation task. The proposed machine integrates soil removal, a reserved vision-based yellow-leaf detection and root-trimming station, multi-angle disinfection, water–air washing, combined airflow drying, film wrapping, weighing, and boxing modules on a chain-conveyor platform with bowl-shaped fixtures. The evaluation follows a design-to-evidence workflow: lettuce morphology and process requirements are mapped to module geometry; chain, lead-screw, gear, and motor parameters are checked analytically; an application-oriented geometric spray-coverage model tests fixed versus swinging bilateral nozzles; static finite element analysis screens the frame under defined design loads; and prototype assembly verifies spatial compatibility. The covered-surface proxy increased from 7.24% for fixed bilateral spraying to 13.58% for a ±35° swinging case under explicit screening assumptions, while the frame analysis gave 0.0224 mm maximum deformation and 7.30 MPa maximum von Mises stress. These outputs support a preliminary, mechanically feasible platform and a testable explanation for why adjustable spray orientation may improve access to complex lettuce surfaces. They do not constitute measured cleaning, microbial, trimming, drying, packaging, throughput, or reliability performance. Full article

The rapid growth of electric-vehicle charging demand has increased the need for reliable station-level congestion monitoring and early warning. Existing studies mainly predict charging demand, load, occupancy, or availability, whereas charging congestion pressure is usually shaped by multiple operational factors. This study proposes an interpretable station-level charging congestion pressure assessment and multi-horizon early-warning framework. A Charging Congestion Pressure Index (CCPI) is constructed by integrating occupancy, arrival pressure, charging or occupation duration, service volume, and price–time context into a unified station–hour pressure representation. Based on temporally aligned current, lagged, and rolling features, future high-pressure states are predicted at 1 h, 3 h, and 6 h horizons. Using 1423 charging stations and 6,181,512 station–hour observations from September 2022 to February 2023, this study evaluates whether the proposed station–hour pressure representation can support multi-horizon high-pressure warning under temporal and station-level validation settings. Results show that current pressure is a strong short-term persistence baseline, while learning-based models provide larger F1-score gains at longer horizons. Extreme Gradient Boosting (XGBoost) achieved F1 gains of +0.022, +0.040, and +0.068 over the persistence baseline at the 1 h, 3 h, and 6 h horizons, respectively. Ablation, temporal validation, station holdout validation, and block-bootstrap tests further support the stability of the proposed framework. These findings indicate that interpretable pressure-index construction and temporally consistent multi-horizon warning can provide an engineering decision-support basis for charging-infrastructure operation, station-level congestion monitoring, and proactive resource management. Full article

Electromechanical actuators (EMAs) are increasingly used in aerospace servo actuation because of their compact structure, high power density, and convenient integration with electric flight-control systems. However, load-side aerodynamic torque, friction, parameter perturbations, and unmodeled transmission effects enter the EMA dynamics through a channel different from the motor-current input, which leads to a mismatched disturbance rejection problem. This paper develops a feedback-linearization-assisted observer-based interconnection and damping assignment passivity-based control (IDA-PBC) method for EMA trajectory tracking. A fourth-order input–output feedback-linearized normal-coordinate model is first derived, through which the original load-side mismatched disturbance is transformed into a matched term acting on the highest-order channel. An extended state observer is then constructed to estimate the transformed disturbance. Based on the observer output, a desired Hamiltonian function is generated from a Lyapunov equation, and the interconnection and damping matrices are explicitly assigned so that the closed-loop tracking-error dynamics admit a dissipative port-Hamiltonian representation. A composite Lyapunov analysis proves closed-loop exponential stability under the assumption of slowly varying disturbance. The resulting framework combines the disturbance-channel-reshaping capability of feedback linearization with the energy-shaping interpretation of IDA-PBC, providing a systematic controller design for high-precision EMA servo systems subject to load-side disturbances. Full article

Transnational higher education (TNE) partnerships between Chinese and UK universities continue to expand. However, the structural conditions that shape teaching quality and the governance arrangements through which they are managed remain under-theorised from a faculty-centred perspective. Drawing on a survey-based mixed-methods cross-sectional study of 56 teaching staff (80% response rate) at a Sino-British dual-degree engineering programme in western China, this study provides single-case evidence that teaching workload was the strongest observed negative correlate of perceived institutional support/satisfaction. Total weekly teaching load was moderately and negatively associated with the overall support/satisfaction composite (Spearman’s ρ = −0.49, p < 0.001). Non-parametric paired comparisons showed that teaching facilities were the only support dimension that differed significantly between the two institutional contexts, with a moderate effect; the remaining dimensions showed no significant differences. Internal consistency was acceptable to good. Qualitative thematic analysis identified three faculty adaptation strategies: simplifying and contextualising course materials, using bilingual instructional resources, and scaffolding peer-based discussion. Exploratory teaching-method comparisons involving 13 paired tests, interpreted descriptively, indicated higher reported use of reflection exercises and project-based learning at the joint school campus. An exploratory, perception-based engagement paradox also emerged: faculty reported a higher proportion of students showing >75% active participation at the joint school campus (85.7%) than at the parent institution (70.4% of valid responses), despite rating joint-school infrastructure lower. This finding requires student-level validation. The study contributes an empirically grounded, faculty-centred account of workload governance in transnational partnerships, using the Sino-British case as an illustrative test site. Full article

In order to study the mechanical properties of L-shaped columns of recycled aggregate concrete-filled steel tubes (L-RACFST) with a recycled aggregate concrete (RAC) coarse aggregate replacement rate of 100%, three L-RACFST columns with a RAC coarse aggregate replacement rate of 100% were made to carry out axial compression and two-way bias point load tests. The finite element numerical model was verified on the basis of the test. ANSYS was used to investigate the influence of steel strength, steel thickness, width-to-thickness ratio, and eccentricity on the mechanical properties of L-RACFST columns. Results show that: (1) The eccentricity significantly affects the compressive bearing capacity of L-RACFST columns. Compared with the axial compression specimens, the ultimate bearing capacity of the specimens with eccentricities of 40 mm and 80 mm decreases by 18.67% and 24.84%, respectively. (2) An eccentric load will exacerbate the comprehensive bending deformation of the test specimen. (3) During parameter design, eccentricity has a significant effect on the compressive load-bearing capacity of L-RACFST columns with a 100% RAC replacement ratio. However, increasing the steel’s thickness and strength and reducing the width–thickness ratio can effectively compensate for the loss of compression performance caused by eccentricity. The findings of this study provide guidance for the engineering design and application of steel tube RAC composite special-shaped columns with a high replacement rate. Full article

Regular exercise mediates inter-tissue communication between skeletal muscle and the immune system through skeletal muscle-derived secretory factors, providing an important molecular basis for the beneficial effects of exercise on chronic inflammation, metabolic dysregulation, and impaired tissue repair. As key effector cells of the innate immune system, macrophages do not simply conform to a dichotomous classification of classically activated M1 macrophages and alternatively activated M2 macrophages; rather, their functional states constitute a dynamic spectrum shaped by exercise load, recovery time window, tissue microenvironment, and disease context. This review focuses on recent advances in exercise-induced skeletal muscle secretory factors involved in macrophage functional remodeling. Representative signals, including interleukin-6 (IL-6), irisin, meteorin-like protein (METRNL), fibroblast growth factor 21 (FGF21), oncostatin M (OSM), decorin, myostatin, chemokines, and extracellular vesicles, are systematically summarized in terms of their exercise responsiveness, evidence for skeletal muscle origin, and evidence supporting macrophage regulation. Based on these dimensions, an evidence-strength grading framework is further proposed. Moreover, this review integrates key signaling axes, including glycoprotein 130 (gp130)/Janus kinase (JAK)/signal transducer and activator of transcription (STAT), signal transducer and activator of transcription 6 (STAT6)/peroxisome proliferator-activated receptor gamma (PPARγ), AMP-activated protein kinase (AMPK)/nuclear factor erythroid 2-related factor 2 (Nrf2)/nuclear factor kappa B (NF-κB), transforming growth factor beta (TGF-β)/Smad, and chemokine receptor pathways, to explain how exercise-induced secretory networks participate in the dynamic regulation of the macrophage functional spectrum through immune cell recruitment, inflammatory clearance, immunometabolic reprogramming, matrix remodeling, and repair-niche formation. Current evidence indicates the translational potential of exercise-induced skeletal muscle secretory factors in skeletal muscle repair, metabolic inflammation, aging-related functional decline, and cancer rehabilitation. However, this field still faces several major challenges, including insufficient tracing of skeletal muscle-derived signals, limited direct causal validation, a lack of human tissue-level evidence, and unclear exercise dose–response relationships. Future studies should combine tissue-specific genetic interventions, receptor blockade, single-cell and spatial omics, metabolic flux analysis, and standardized human exercise interventions to further clarify the mechanistic basis and application boundaries of exercise-induced skeletal muscle–macrophage communication, thereby providing a theoretical foundation for precision exercise prescription and chronic inflammation intervention. Full article

To address the critical challenge of extracting short-period surface deformation signals induced by extreme floods from InSAR time series, this study focuses on the catastrophic flood that struck the Haihe River Basin in July 2023 (hereinafter referred to as the “23·7” flood, with a total duration of approximately 65 days) and proposes a novel method for transient deformation signal extraction. Using Sentinel-1A satellite data and the PS-InSAR technique, we constructed a multivariate composite fitting function comprising a linear trend term, annual and semi-annual seasonal terms, a step term, and a logarithmic decay term. Through nonlinear least-squares fitting, this approach achieves effective separation of long-term tectonic deformation, seasonal fluctuations, high-frequency noise, and transient flood-related signals. The results show that the W-shaped floodplain east of Xiong’an New Area does not exhibit the expected subsidence induced by water loading but instead features pronounced surface uplift of up to 30 mm. Multi-physics forward modeling reveals the underlying mechanism: the elastic subsidence caused by surface water loading, calculated via the LoadDef spherical loading theory, amounts to only ~2 mm. In contrast, forward modeling based on the GMS three-dimensional groundwater seepage model and the principle of effective stress indicates that the pore water rebound effect can produce surface uplift of up to ~36 mm. The superposition of these two effects is highly consistent with InSAR observations in terms of magnitude, direction, and spatial distribution, confirming that the flood-induced surface deformation is dominated by the pore water rebound effect driven by rapid groundwater recharge, rather than subsidence from water loading. The proposed framework extends the application potential of geodetic techniques for monitoring short-period extreme hydrological events. Full article