Search Results (5,324)

Argillaceous siltstone forms water-sensitive weak layers in red-bed slopes, but its multiscale deterioration under wet–dry cycling remains incompletely understood. Specimens subjected to 0, 1, 3, 5, 7, and 9 cycles were examined through uniaxial compression, energy analysis, digital image correlation (DIC), and microstructural and mineralogical characterization. The mean unconfined compressive strength (UCS) decreased by 36.0% after the first cycle and then remained broadly stable, with modest fluctuations, from 1 to 5 cycles. At five cycles, the elastic modulus remained substantially below the natural-state value, and although total strain energy approached the natural-state level, elastic strain energy remained lower and the dissipated energy ratio more than doubled, indicating continued irreversible damage. The characteristic calcite diffraction peak was no longer detected in the X-ray diffraction (XRD) patterns, while microstructural observations showed redistributed fines within pores together with a temporary decrease in face porosity. With further cycling, the UCS declined again and was 59.0% below its initial level after nine cycles. Meanwhile, strain fields and failure patterns evolved from localized deformation and splitting to distributed cracking and surface spalling, while particle detachment reopened pores and increased face porosity to 14.37%. These observations are consistent with a dissolution–filling–detachment mechanism and suggest that the intermediate UCS stabilization reflected temporary maintenance of load-bearing capacity rather than recovery of the original rock skeleton. Full article

The vestibular system contributes to cardiovascular regulation during changes in gravitational load (e.g., postural transitions, microgravity), in vestibular disorders, and during vestibular stimulations. Studies employing sinusoidal galvanic vestibular stimulation (GVS) reported conflicting autonomic responses, and recent evidence suggests that vestibular afferents encode GVS in a non-linear fashion. Whether this non-linear encoding results in polarity-dependent autonomic responses and whether such responses interact with concurrent cognitive demand remains unknown. To investigate these issues, we used sinusoidal GVS to modulate vestibular input in 35 healthy individuals while physiological signals were recorded using a wearable device. Participants completed a working memory task, preceded and followed by rest periods, under three counterbalanced conditions: right-anodal/left-cathodal GVS (RGVS), left-anodal/right-cathodal GVS (LGVS), and Sham GVS. Perceived stress was repeatedly assessed. During task performance, heart rate increased with RGVS and decreased with LGVS relative to Sham (p = 0.001) and perceived stress increased across all conditions (p < 0.001). Post-task, heart rate remained elevated in RGVS compared to LGVS (p = 0.006), and stress ratings decreased in LGVS compared to the other conditions (p < 0.01). These findings indicate that sinusoidal GVS induces polarity-dependent autonomic effects, primarily during concurrent cognitive demand. This pattern may reflect non-linear vestibular encoding, with its emergence being potentially modulated by attentional shifts. Full article

Background and Objectives: Caries experience, plaque accumulation, gingival inflammation, and periodontal screening findings may coexist as manifestations of a shared oral-health burden. We examined whether these routinely recorded indicators form distinct multivariable profiles or primarily represent ordered levels along a common burden continuum in children and adolescents. Materials and Methods: This secondary exploratory analysis included 638 participants from a multicenter cross-sectional clinical database: 407 aged 6–12 years and 231 aged 13–19 years. Permanent-dentition Decayed, Missing, and Filled Teeth score, Plaque Index, Gingival Index, and Community Periodontal Index were standardized and analyzed separately by age stratum. Unsupervised K-means clustering compared solutions containing two to five groups to summarize participant-level patterns without imposing predefined clinical categories. Hierarchical Ward classification assessed algorithmic concordance; principal component analysis and a composite standardized burden score assessed dimensionality. Sensitivity analyses excluded the periodontal index or treated it as ordinal with Gower-distance partitioning around medoids, and 1000 repeated 80% subsamples assessed sampling stability using the adjusted Rand index. Results: A single principal component explained 91.0% of variance at 6–12 years and 91.8% at 13–19 years, with all four indicators loading strongly on the same dimension. Ordered cluster membership correlated closely with the composite burden score (Spearman ρ = 0.942 and 0.939; both p < 0.001). The retained low-, intermediate-, and high-burden groupings were highly consistent when the periodontal index was excluded or treated as ordinal and under repeated subsampling. In adolescents, a two-group alternative preserved the low- and high-burden extremes while dividing the intermediate group, indicating that the number of groups changes descriptive granularity rather than revealing a separate phenotype. Conclusions: The principal new finding is that four commonly used oral-health indicators converge on one dominant participant-level burden dimension rather than defining distinct clinical phenotypes. This supports an integrated epidemiological description of cumulative oral-health burden while cautioning against interpreting data-driven groups as diagnostic or treatment categories. The numerical group distributions are sample-specific and require external and longitudinal validation before being transferred to other populations or clinical decision-making. Full article

The structural instability of cylindrical shells has long attracted scholarly attention due to its inherently nonlinear response and extensive engineering relevance. Although numerous investigations have examined buckling phenomena arising from individual loading modes such as axial compression or pure torsion, the complex behavior of shells subjected to simultaneous torsional and axial actions remains comparatively underexplored. In this study, an integrated approach combining theoretical formulations and finite element analyses is employed to comprehensively characterize the buckling responses of cylindrical shells under coupled torsional–axial loading conditions. The theoretical framework is developed using Donnell’s shell theory and solved through the Galerkin approximation. The predicted results exhibit strong agreement with finite element simulations. It is demonstrated that the buckling evolution of cylindrical shells under combined loading markedly differs from that produced by a single load component. Specifically, shells under torsion with minor compression display a stable deformation mode, whereas higher compression induces a transition toward a diamond-shaped buckling pattern. Such findings elucidate the coupled torsion–compression/tension effects governing buckling instabilities in cylindrical shells, offering valuable insight for the design of load-responsive foldable and origami-inspired structures driven by combined mechanical actions. Full article

Reflective cracking is one of the primary causes of premature deterioration in asphalt-overlaid Portland cement concrete (PCC) pavements, reducing service life and increasing maintenance costs. Since crack initiation begins within the underlying PCC layer before becoming visible at the pavement surface, conventional inspection methods have limited capability for early damage detection and continuous monitoring. This study presents a hybrid experimental–numerical framework for monitoring and interpreting bottom-up reflective cracking by integrating Optical Frequency Domain Reflectometry (OFDR)-based Distributed Fiber-Optic Sensing (DFOS), laboratory-scale three-point bending tests, and finite element (ABAQUS) modeling. Rectangular and semi-cylindrical asphalt-overlaid PCC specimens were instrumented with surface-bonded distributed optical fibers arranged in a serpentine sensing layout with approximately 20 mm spacing to continuously monitor strain evolution during flexural loading. In both tested specimen configurations, the three-point bending tests produced bottom-up crack initiation at the predefined notch within the PCC layer, followed by crack propagation toward the asphalt overlay. Crack-width measurements showed that the maximum crack opening occurred near the notch and progressively decreased toward the asphalt overlay, consistent with the expected flexural stress distribution. The OFDR-based DFOS system successfully identified localized strain concentrations associated with crack initiation and propagation, demonstrating its capability for continuous distributed monitoring of fracture evolution. Finite-element simulations identified tensile stress and strain-localization patterns that showed good qualitative spatial correspondence with the experimentally observed cracking region and distributed strain measurements. The combined experimental, sensing, and numerical results demonstrate the proposed framework’s capability to monitor and interpret bottom-up reflective cracking and highlight the potential of OFDR-based distributed fiber-optic sensing for structural health monitoring, condition assessment, and future field-scale monitoring of rehabilitated concrete pavements. Full article

This study experimentally investigated the punching shear behavior of engineered cementitious composite flat-plate slabs incorporating cement kiln dust and crumb rubber. The considered criteria included replacing 50% of the rubber without treatment and treating the rubber at the same percentage; the flexural reinforcement ratio, whether in the bottom tensile reinforcement ratio or in the top compressive reinforcement; and the ECC cube compressive strength (f_cu). For this purpose, thirteen reinforced flat-plate slabs were cast and tested. All slabs had the same dimensions of 1100 × 1100 × 100 mm, with a central square column that had dimensions equal to 160 × 160 × 160 mm. The flexural RFT ratios in the tension and compression zones were 1.0, 1.2, and 1.6%. The tested slabs were cast with different values of f_cu of 50, 65, and 70 MPa. The study first presented and discussed the first cracking load, ultimate load, crack pattern, load–deflection response, stiffness, and RFT strain. The experimental results demonstrated that increasing the tensile reinforcement RFT ratio significantly improved punching shear capacity by up to 33%, while the concrete cube compressive strength only contributed an approximately 14.2% increase. Treated crumb rubber engineered cementitious composite slabs showed greater initial stiffness and reduced deflections under the same loads, along with higher post-cracking stiffness degradation compared to crumb rubber concrete engineered cementitious composite slabs. Increased tension reinforcement improved initial and post-cracking stiffness and reduced deflections, with more significant effects in crumb rubber concrete engineered cementitious composite slabs. The flexural tension had a more substantial impact on punching shear behavior than compression. Comparisons with building design codes (ECP 203-2020, ACI 318-25, and Eurocode 2) revealed that while these codes could estimate shear capacity, they were conservative, with Eurocode 2 providing the best predictions by considering flexural tension. Full article

High penetration of wind and photovoltaic generation reshapes power system net-load profiles and increases the computational burden of repeatedly solving security-constrained unit commitment problems under multiple renewable scenarios. This paper proposes a fast schedule generation method based on historical schedule transfer. A library is constructed by pairing feasible unit commitment schedules with their corresponding 24 h net-load trajectories. For a target day, hour-wise, standardized net-load trajectories are compared using Euclidean distance, and the Top-K most similar historical schedules are selected as candidates. Each candidate is verified under the target-day operating conditions. When no candidate satisfies the feasibility or economic requirements, a limited-perturbation model is applied to repair the retrieved schedule with minimal changes in unit statuses. Case studies show that the proposed method effectively transfers historical commitment patterns, maintains operational feasibility and near-optimal economic performance, and reduces the computational effort required for unit commitment schedule generation. Full article

In this work, a bandpass filter (BPF) based on a half-mode substrate integrated waveguide loaded with spoof surface plasmon polaritons (HMSIW-SSPP) is proposed. To explore the high-dimensional metallic pattern space of the SSPP loading region, an artificial intelligence (AI)-assisted surrogate optimization framework is developed. The editable SSPP loading region is discretized into 351 binary cells, and a frequency-weighted principal component analysis (PCA)-based convolutional neural network (CNN) surrogate is constructed to predict full-band electromagnetic responses while preserving key spectral features. Based on the trained surrogate, proximal policy optimization (PPO) is employed to optimize the binary pattern through a sequential keep-or-flip strategy. Full-wave simulations show that the optimized filter achieves a passband of 2.97–7.55 GHz, with return loss better than 12 dB and stopband suppression better than 20 dB. A prototype is fabricated and measured for validation, showing a passband of 2.95–7.52 GHz, a fractional bandwidth of 87.3%, a minimum insertion loss of 0.95 dB, and return loss better than 11.7 dB. These results verify the proposed HMSIW-SSPP topology and demonstrate the effectiveness of the frequency-weighted PCA-CNN-assisted PPO framework. Full article

The case of common ragweed (Ambrosia artemisiifolia) stands as a prime example of an invasive plant that links global change, biological invasion, aeroallergen exposure, and allergic airway disease. However, evidence remains fragmented across invasion biology, aerobiology, molecular allergology, and respiratory medicine. By separating plant occurrence, pollen abundance, molecular allergen dose, sensitisation, and airway disease, this review develops an integrated invasion–exposure–disease logic for interpreting ragweed-related health risk. We examine how climate change, land-use disturbance, repeated introductions, rapid adaptation, and air pollution influence plant distribution, flowering phenology, pollen production, airborne allergen load, and respiratory outcomes. Attention is given to Amb a 1 as the principal marker of genuine ragweed sensitisation, cross-reactivity with Artemisia and other weed pollens, allergen-bearing respirable particles, and the diagnostic limitations of extract-based immunoglobulin E (IgE) testing. The literature indicates that ragweed sensitisation follows a pronounced hotspot–gradient pattern in Europe, whereas patterns in other invaded regions remain more heterogeneous and incompletely characterised. Clinically relevant exposure depends not only on pollen concentration but also on airborne allergen load, pollen allergen potency, atmospheric transport, respirable particle fractions, meteorological conditions, and pollution. Ragweed-related airway disease is mediated by IgE-dependent type 2 immunity and amplified by epithelial danger signals, oxidative stress, protease activity, and innate immune pathways. Based on current evidence, we propose that an integrated surveillance framework linking plant distribution, pollen and airborne-allergen exposure, molecular sensitisation, symptoms, lung function, and asthma outcomes could strengthen risk forecasting, source attribution, prevention, and invasion control of the common ragweed. Full article

Chronic bee paralysis virus (CBPV) is a bipartite positive-sense RNA virus that causes significant colony losses in honey bees, yet its tissue-level infection dynamics remain poorly characterized. We performed tissue-resolved virome analysis of two naturally infected Apis mellifera apiaries during a CBPV outbreak in Shandong, China. The apiaries shared a queen source and overwintering site but were separated by over 80 km at the time of sampling and developed contrasting disease patterns. Symptomatic foragers showing characteristic clinical signs of CBPV infection, including trembling, flightlessness, crawling, and hairless dark cuticle, and asymptomatic foragers were collected. Head, thorax, and midgut tissues were then dissected and used for RNA sequencing, yielding 36 RNA-seq libraries. In symptomatic bees, CBPV dominated the virome, with viral loads highest in heads and lowest in midguts. The RNA1/RNA2 copy ratio revealed a conserved tissue-specific gradient, shifting from RNA2 predominance in heads and thoraces to RNA1 enrichment in midguts (p = 0.024 for each apiary). This directional imbalance was validated by multiple controls and conserved across two genetically distinguishable CBPV populations, implicating the host tissue environment as the primary driver. In asymptomatic bees, the two apiaries harbored markedly different covert viromes, with CBPV dominant in the heads and thoraces of one apiary and near-exclusive Lake Sinai virus dominance in the other. These findings reveal that CBPV segment stoichiometry is modulated in a tissue-dependent manner in vivo and that viral genetic composition and covert virome composition can diverge notably between epidemiologically connected apiaries, providing additional insight into the infection biology of CBPV under natural conditions. Full article

Material extrusion (MEX) enables rapid fabrication of single-use polymer casting patterns for foundry and mechanical engineering applications, where handling strength and surface texture are critical. This study examines how infill pattern, density, and orientation affect the mechanical and surface properties of samples printed from ELEGOO PLA on a Bambu Lab A1 using Bambu Studio 2.5.0. Two infill types (triangle, grid), two densities (50%, 70%), and five orientations were evaluated via uniaxial tension, fixed-deflection three-point bending, line-profile and areal surface texture measurements, and SEM fracture analysis. Tensile strength ranged from 23.60 to 29.19 MPa. Raising infill density from 50% to 70% increased mean tensile strength from 24.62 to 27.65 MPa. The highest tensile strength, 29.19 MPa, occurred for a 70% grid infill at 75° orientation; the highest bending load at 4 mm midspan deflection, 107.97 N, occurred for a 70% grid infill at 15°. Across the descriptive surface dataset, differences among the top, side, and bottom surfaces were greater than the variations associated with infill orientation. Top, side, and bottom surfaces formed via different mechanisms; the relatively high bottom-surface roughness arose from replication of the textured PEI build plate. The selected lower-density fracture surfaces exhibited more pronounced visible gaps and inter-bead discontinuities in the SEM images. Within the tested range, the 70% grid infill produced the best overall mechanical performance. These findings are specific to the ELEGOO PLA–Bambu Lab A1–Bambu Studio 2.5.0 system and should not be interpreted as intrinsic PLA properties, used for direct cross-material benchmarking, or assumed to represent behavior under industrial foundry conditions. Instead, they provide system-specific screening data for selecting candidate infill configurations and for the subsequent evaluation of this commercial MEX printing platform for producing single-use polymer casting patterns for complex-geometry components in mechanical engineering under representative foundry conditions. Full article

Background: Myocardial infarction (MI) causes spatially heterogeneous loss of contractility and progressive extracellular matrix remodeling, altering left ventricular mechanics from the acute phase through chronic remodeling. This review integrates current understanding of infarct, border-zone, and remote-myocardial microstructure with organ-scale mechanics and patient-specific computational modeling. Methods: A narrative review and perspective were conducted using the literature identified through PubMed/MEDLINE, Scopus, and Web of Science, supplemented by targeted searches of IEEE Xplore and Google Scholar. Experimental, imaging, computational, and translational studies were synthesised, with emphasis on post-MI constitutive behaviour, finite-element and growth-and-remodeling models, imaging-informed personalization, inverse parameter estimation, identifiability, model calibration, verification and validation, and uncertainty quantification. No quantitative synthesis was performed because of substantial heterogeneity in study populations, imaging modalities, constitutive formulations, boundary conditions, calibration procedures, and reported outcomes. Results: Contemporary post-MI models can reproduce ventricular volumes, regional strain patterns, and selected haemodynamic measures, while enabling counterfactual simulations of infarct stiffness, border-zone contractility, and loading interventions. However, clinically credible prediction remains constrained by limited in vivo observability of regional tissue properties, poor parameter identifiability, confounding between material properties and loading conditions, and incomplete treatment of measurement, parameter, and model-form uncertainty. Conclusions: The novelty of this review lies in framing post-MI patient-specific modeling as an identifiability- and uncertainty-limited inverse problem rather than solely as a model-fitting exercise. It proposes that translation toward decision-grade prediction requires parsimonious models aligned with a defined clinical context of use, constrained by microstructure-informed priors, multimodal pressure–volume–strain data, longitudinal validation, and routine reporting of parameter identifiability and predictive uncertainty. Full article

Background/Objectives: Autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) are frequently co-occurring neurodevelopmental conditions with partially overlapping neurophysiological profiles. Electroencephalography (EEG) provides non-invasive access to candidate biomarkers, yet the literature remains largely organized around single-diagnosis frameworks, limiting comparison across conditions and constraining translation into intervention selection. This review compares EEG signatures across ASD and ADHD from a transdiagnostic perspective and examines how such signatures might inform the selection of non-pharmacological interventions. Methods: A structured search of PubMed, Scopus, IEEE Xplore and Web of Science identified peer-reviewed studies published between 2010 and 2026 reporting EEG findings in ASD and/or ADHD, spanning resting-state, task-based, connectivity, event-related potential, machine learning and intervention studies. Sixty-eight sources were synthesized thematically. Given substantial heterogeneity in acquisition parameters and analytic pipelines, evidence was integrated interpretively rather than pooled quantitatively, and no formal risk-of-bias assessment was undertaken. Results: Shared features across both conditions frequently included low-frequency theta excess, reduced alpha modulation under cognitive load, and flattened aperiodic (1/f) slopes—a pattern compatible with, though not a direct measurement of, altered excitation/inhibition balance. While substantial heterogeneity exists, disorder-specific signatures often comprised the ASD “U-shaped” spectral profile alongside elevated epileptiform activity, and frontally pronounced theta/beta ratio elevation in subsets of individuals with ADHD. Machine-learning studies increasingly emphasize interpretable, multidomain feature sets over binary classification. Mindfulness-based and neurofeedback interventions converge on theta reduction and alpha enhancement, although reported effects are frequently conditional on responder status, task context, or outcome-rater blinding. Conclusions: Convergent EEG features support a transdiagnostic account of neurodevelopmental dysregulation. A biomarker-informed framework for intervention selection is proposed, which requires prospective validation before clinical application. Full article

River sediments act not only as important sinks for heavy metal pollution in watersheds, but also as potential secondary sources under changing environmental conditions. Heavy metals can enter river systems through industrial wastewater discharge, agricultural non-point runoff, urban stormwater and sewage inputs, mining and smelting activities, and atmospheric deposition. During adsorption onto suspended particles, sedimentation, and resuspension, metals such as Cd, Pb, Cr, Cu, Zn, Ni, As, and Hg progressively accumulate in sediments. Because heavy metals are persistent, non-degradable, and bioaccumulative, contaminated sediments can record historical watershed pollution while also releasing metals back into overlying water under hydrodynamic disturbance, pH and redox fluctuations, organic matter mineralization, benthic bioturbation, and dredging activities, thereby threatening aquatic ecosystem stability and human health. Using a global methodological framework with particular emphasis on Chinese river basins, this review systematically summarizes key issues in the study of heavy metal pollution in river sediments, including spatial–temporal distribution and operationally defined fractionation, pollution levels and ecological risk assessment, source apportionment, and remediation and management technologies. Current evidence indicates that heavy metal contamination in river sediments exhibits pronounced spatial heterogeneity and watershed-specific characteristics. Its distribution is jointly controlled by geological background, land use patterns, source input intensity, hydrodynamic conditions, sediment particle size composition, and organic matter content. Methodologically, the field has evolved from single total concentration monitoring and exceedance-based evaluation toward integrated assessment systems that combine total concentrations, operationally defined fractionation, bioavailability, ecological risk, health risk, and source contribution. The joint use of BCR sequential extraction, the geoaccumulation index (Igeo), the pollution load index (PLI), the potential ecological risk index (RI), the risk assessment code (RAC), sediment quality guidelines (SQGs), receptor models, isotope tracing, and machine learning has substantially improved pollution identification, risk zoning, and source apportionment. Overall, research on heavy metal pollution in river sediments has shifted from descriptive judgments of whether contamination exists toward mechanistic and management-oriented questions concerning pollution sources, risk evolution, and remediation strategies. However, important gaps remain in compound pollution transformation mechanisms, regional background values and evaluation benchmarks, uncertainty in model parameters, long-term dynamic monitoring, and engineering-scale verification of remediation technologies. Future studies should strengthen multi-media, multi-scale, and long-term monitoring and further integrate fractionation analysis, toxicological effects, source apportionment models, and remediation technologies to provide a scientific basis for watershed ecological security and precision management of contaminated sediments. Full article

Carbon fiber-reinforced polymer (CFRP) composites are widely used in curved aerospace structures, where riveting-induced interlaminar damage is a critical concern. Most existing studies have focused on flat laminates, while the influence of structural curvature on rivet load transfer and delamination tendency remains insufficiently understood. This study develops a three-dimensional finite element model in ANSYS Workbench to investigate the curvature–interference coupling effect on CFRP/Al single-lap riveted joints. Four curvature configurations with identical arc lengths (C0, C45, C90, and C180) are established, and riveting is simulated with upsetting displacements of 1.5–3.0 mm. Results show that curvature shifts the contact pressure from an axisymmetric pattern to a localized distribution on the convex side, while the deformation mode transitions from isotropic expansion to hoop-dominated behavior. The equivalent interlaminar shear stress increases nonlinearly with curvature and displacement. At 3.0 mm, the peak stress in C180 reaches 415.9 MPa, 1.86 times that of the flat laminate. Further analysis reveals that curvature induces membrane-bending coupling, which amplifies ply deformation incompatibility and increases delamination tendency. These findings indicate that riveting parameters developed for flat laminates cannot be directly transferred to curved structures, and curvature–interference coupling should be considered in damage-tolerant design. Full article