Search Results (1,020)

In this study, the seismic vulnerability of the Ferdowsi School building in Tabriz is investigated. The research began with comprehensive fieldwork, during which exploratory surveys and in-depth technical inspections of all structural components were performed. Experimental testing of prismatic masonry specimens was carried out to evaluate their mechanical characteristics, and the resulting properties were then incorporated as input parameters into the numerical model. The seismic vulnerability assessment was then carried out using nonlinear static (pushover) analysis, applying a lateral load pattern proportional to the first vibration mode of the structure. For numerical simulation, the building was modeled in the ABAQUS finite element software using the macro-modeling technique. The results of the nonlinear static analysis indicated that the building does not possess sufficient load-bearing capacity at the target displacement. Damage was primarily concentrated in the form of cracking in the masonry walls as well as in the dome-shaped sections of the roof, requiring the implementation of a seismic retrofitting scheme to enhance the structure’s seismic performance. To rehabilitate the structure, horizontal and vertical reinforced concrete beams were introduced as confining elements for the masonry walls and subsequently applied in the strengthening project. Furthermore, due to the presence of a domed roof at the first-floor level, it was strengthened using FRP composite materials to enhance tensile capacity and ductility. At the second-floor level, where the roof structure is made of timber elements, a steel cable system was employed to improve its strength and diaphragm action. As for the third-floor timber truss roof, the connections were upgraded and reinforced to provide reliable force transmission and to maintain the overall integrity of the structural system. Following the implementation of the retrofitting measures, the structural model was re-analyzed using nonlinear static analysis. The results demonstrated that the proposed strengthening scheme successfully increased the structural capacity up to the target displacement level and satisfied the intended performance requirements. In the final section of the paper, the implementation details of the retrofitting interventions, as well as the practical experiences gained during the implementation process, are presented and discussed. Full article

Aiming at the problem that strip surcharge in coastal soft soil foundations causes lateral squeezing and endangers the safety of adjacent existing bridge pile foundations, the traditional Boussinesq elastic theory cannot reflect the true elastoplastic characteristics of the soil and tends to underestimate the actual horizontal additional stress. This paper establishes a two-dimensional plane strain finite element model and, based on the calibration of pure elastic theoretical solutions, carries out extensive comparative analyses under elastoplastic foundation conditions. Through Pearson correlation and random forest sensitivity analyses, it is clarified that the internal friction angle, load ratio, and normalized distance ratio are the core control variables affecting the redistribution of horizontal additional stress, thereby demonstrating the limitations of the influence of elastic modulus and cohesion. The study reveals the nonlinear amplification mechanism of horizontal stress transfer caused by the penetration of the deep plastic zone within the foundation, as well as the physical evolution law of the stress correction factor, which initially exhibits a Gaussian peak enhancement and subsequently decays exponentially with spatial distance. Based on these mechanisms, a combined prediction formula for the horizontal additional stress correction factor is proposed, achieving an R² = 0.903, and a safety evaluation chart for the correction factor is constructed to quantify high-risk areas. The results indicate that when the normalized distance ratio is greater than or equal to 4, the elastoplastic squeezing effect essentially dissipates. The proposed modification method effectively delineates the applicable boundary of the elastic solution and provides a theoretical basis for the bearing capacity calculation and safety control of passively loaded pile foundations in soft soil regions. Full article

This study comprehensively examines the whole-genome sequence and probiotic potential of Lacticaseibacillus paracasei RM081, a strain originally isolated from raw bovine milk. Whole-genome sequencing and in silico analyses provided a robust molecular basis for its functional traits. The L. paracasei RM081 genome harbors an extensive repertoire of carbohydrate-active enzymes, suggesting strong prebiotic utilization capabilities. Crucially, genomic mining identified key genetic determinants for postbiotic synthesis, including the potential to synthesize the anti-inflammatory metabolite 5-methoxytryptophan (5-MTP). Moreover, comprehensive safety evaluations confirmed the absence of transferable antimicrobial resistance genes, virulence factors, biogenic amine-producing genes, and plasmids, indicating a secure genomic architecture without horizontal gene transfer risks. These genomic predictions were further substantiated by valid in vitro phenotypic models. The strain exhibited strong tolerance to gastric acid, maintaining high viability at pH 3.5 and 2.5 after 4 h, and survived well at 0.1% bile salt concentration. Furthermore, L. paracasei RM081 demonstrated robust cell surface properties, with a high auto-aggregation rate (85.0 ± 0.7%), hydrophobicity (71.5 ± 2.4%), and 78.0 ± 4.8% adhesion to Caco-2 intestinal epithelial cells, supporting its potential for colonization. Regarding antioxidant capacity, the cell-free supernatant displayed the highest DPPH scavenging activity (37%), indicating the active secretion of antioxidative metabolites. Collectively, these findings establish L. paracasei RM081 as a highly promising, safe probiotic and postbiotic candidate with verified colonization potential and functional capabilities. Full article

Conventional masonry infill walls can significantly alter the seismic response of framed buildings and often produce damage patterns incompatible with resilience-based seismic design. Dry-jointed sliding masonry wall systems have therefore emerged as deformation-tolerant alternatives that accommodate drift through controlled interface motion rather than damage accumulation. This study investigates the sequential in-plane (IP) and out-of-plane (OOP) behavior of such systems considering wall thickness, openings, and boundary detailing. Six full-scale specimens were tested, including thick- and thin-wall reference specimens, thick-wall specimens with window openings, and thin-wall specimens with door openings. IP performance was evaluated using global hysteretic and energy-based response parameters, whereas OOP behavior was assessed through load–displacement response, an equivalent acceleration index, and selected image-based displacement fields. The results show that IP drift was mainly accommodated through distributed sliding along horizontal interfaces and local block rotation, without diagonal compression strut formation or brittle cracking, even at drift ratios up to approximately 3.5%. Wall thickness improved IP strength, stiffness, shear resistance, and cumulative energy dissipation, while openings mainly affected deformation compatibility and load-transfer continuity. Under OOP loading, wall thickness and boundary continuity increased stiffness and capacity while enabling resistance mobilization at smaller displacement levels. As inertia-based comparison indicators, boundary-enhanced thick- and thin-wall specimens reached equivalent acceleration capacities of 3.41 g and 1.64 g, respectively. Overall, the system reduced IP damage accumulation, but adequate OOP stability requires appropriate wall thickness, unit geometry, and boundary detailing. Full article

The exponential growth of AI-driven data traffic necessitates the evolution of Data Center Networks toward high bandwidths and sub-microsecond latency. While co-packaged optics (CPO) offer a pathway to reduced energy consumption and increased capacity, they introduce significant challenges in optical chip coupling and packaging complexity. This study explores monolithically integrated metasurfaces as an alternative for optical interfaces, potentially reducing the need for bulky external microlens arrays or extremely precise mechanical alignment. We design an amorphous silicon (a-Si) metasurface on a Silicon-On-Insulator (SOI) platform operating at 1310 nm. By spatially mapping nanopillar radii to satisfy a spherical phase profile, we achieved near-vertical beam emission with an emission angle of 0.88° focused at a focal length of 98.99 μm. Broadband characterization across a 20 nm band confirms stable focusing and a confined spot size with moderate roll-off toward the band edges. The sensitivity of the emission profile of the device to fabrication imperfections in pillar radius, height, and sidewall taper is quantified. The coupling to a polymer-based optical redistribution layer (ORDL) is also studied, and the corresponding modal analysis demonstrates a maximum coupling efficiency of 68.2% into an SU-8 polymer waveguide. Tolerance analysis results reveal deterioration of 0.9 dB and 0.4 dB for $\pm 0.6 \mathsf{\mu }\mathrm{m}$ horizontal and $\pm 1.5 \mathsf{\mu }\mathrm{m}$ vertical misalignment respectively, making the interface compatible with relaxed alignment assembly assumptions, although experimental packaging validation remains required. The methodology is further validated at 1550 nm, demonstrating its applicability across telecom bands. These results suggest that integrated metasurfaces may simplify the packaging stack and enhance density for next-generation CPO links by providing precise, on-chip wavefront manipulation. Full article

Climate warming, pavement heat storage and lateral heat intrusion accelerate active-layer deepening and uneven thaw settlement along permafrost transportation corridors. In wide asphalt embankments, heat is stored across a broad pavement-embankment section, while slope-aspect solar input drives asymmetric thermal erosion toward the sunny-side toe. Existing embankments protected by two-phase closed thermosyphons (TPCTs) are commonly evaluated by temperature reduction, maximum thaw depth or local cooling efficiency, but these metrics do not describe frozen-state continuity or residual weak zones. This study develops a three-dimensional hydrothermal model to compare a no-TPCT reference embankment, a conventional inclined TPCT layout and a base-arranged novel horizontal TPCT layout under long-term regional warming. Without TPCTs, the year-20 thaw depth reached 10.06 m at the sunny-side shoulder and 9.76 m beneath the centerline, with thermal disturbance propagating toward the sunny-side toe. Both TPCT layouts stabilized the 0 °C isotherm beneath the embankment. The inclined layout generated deep localized cooling, whereas the horizontal layout formed a more continuous shallow frozen zone, with longer operating durations and year-20 annual cumulative cooling capacities of 1870 and 1600 MJ on the sunny and shaded sides, respectively. The findings support an assessment based on frozen-state continuity, cross-sectional temperature uniformity and residual weak-zone development. Base-arranged novel horizontal TPCTs are better suited to shallow continuity, whereas inclined TPCTs remain useful for deep localized cooling. Full article

To study the soil moisture dynamics and rainfall infiltration characteristics of karst sloping farmland and their driving factors, an abandoned farmland was selected for this study, and five monitoring points (from the foot, S1, of the slope to the top, S5) were set along the terrain gradient. The volumetric water content data of the 0–40 cm soil layer was obtained through in situ monitoring for one year. The infiltration characteristics were quantified in combination with a staining tracer test, and the soil properties were determined. The results showed that the soil moisture content increased with the deepening of the soil layer, and there was significant slope differentiation. The moisture content in the downhill slopes (S1, S2) was significantly higher than that in the uphill slopes (S4, S5), and the annual average value of S5 was 27.4% lower than that of S1. The moisture difference (Δθ, the difference in moisture content between hillslope and flatland) changed from positive to negative from the foot of the slope to the top, indicating that moisture was transported downward along the slope surface. A dye tracer showed that from S1 to S5, the water transport pathway gradually shifted from exhibiting deeper vertical penetration and narrower lateral spread to showing shallower vertical penetration and wider lateral spread. The preferential flow index decreased from 46.6 ± 2.3% to 34.7 ± 2.1%, indicating a progressive reduction in rapid vertical channeling, while the lateral flow index reached its peak (21.4 ± 2.7%) in the middle of the slope (S3), suggesting enhanced horizontal water redistribution at this position. Correlation analysis indicated that soil bulk density was extremely significantly negatively associated with infiltration capacity, while capillary porosity, non-capillary porosity, total porosity, organic matter, and high aggregate content were extremely significantly positively associated with infiltration capacity. These results revealed that the topographic gradient affected soil moisture and water infiltration paths by regulating soil physical properties in this karst forest ecosystem. It should be noted that the research results are only applicable to one slope and should not be directly extended to all karst slope agricultural landscapes. Full article

In this paper, an innovative T-stub connection with square-neck one-side bolts (TS-SNUBC) is developed to improve the bearing capacity and construction reliability of the box column-H beam joint. Twelve T-stub specimens, considering variations in bolt type, flange thickness, and bolt hole orientation, were designed and tested under uniaxial tension. The failure modes, load–displacement responses, ultimate load-bearing capacities, and key quantitative mechanical indicators (initial stiffness, ductility index and cumulative energy dissipation) of the specimens were evaluated. The results indicate that all specimens failed due to the yielding of the thin flange. Specimens with conventional bolts demonstrated the highest load-bearing capacity, followed by those with TS-SNUBC and then slotted one-side bolts. Increasing the thin flange thickness significantly improved the ultimate bearing capacity of the TS-SNUBC specimens. Notably, TS-SNUBC specimens with thin flange thicknesses below 10 mm experienced tear-out failure. Furthermore, specimens with horizontally oriented bolt holes exhibited higher load-bearing capacity than those with vertically oriented holes. A thin flange thickness above 10 mm ensures high initial stiffness, and TF12H has a stiffness of 32.00 kN/mm. Ductility gradually reduces with the growth of thin flange thickness. Energy dissipation decreases sharply when the thin flange is thicker than 10 mm. The joint with 16 mm thick flange, 8 mm thin flange and horizontally arranged square-neck one-side bolts presents the best comprehensive performance. The proposed TS-SNUBC shows favorable bearing performance and initial stiffness, offering a promising solution for reliable and efficiently constructed connections between box columns and steel beams. Full article

Background: In youth football, sprint performance depends on the capacity to produce and orient force horizontally during acceleration. Resisted sprinting may preferentially target the force end of the sprint force–velocity profile, whereas free sprinting may favour velocity-oriented adaptations. Purpose: To compare the effects of resisted versus non-resisted sprint training on sprint performance and sprint force–velocity variables in youth footballers, while monitoring countermovement jump (CMJ) as a secondary outcome. Methods: This parallel-group randomised controlled trial included 44 players from two age categories (U14, n = 21; Youth, n = 23). Within each category, players were randomly allocated to resisted sprint training (RST; U14 n = 11, Youth n = 12) or non-resisted sprint training (NRST; U14 n = 10, Youth n = 11). Both groups completed two supervised sessions per week for six weeks. Outcomes were CMJ and sprint-derived variables including maximal theoretical horizontal force (F0), maximal theoretical velocity (V0), maximal power (Pmax), measured maximal sprint velocity (Vmax), peak ratio of horizontal force (RFpeak), decrease in RF with increasing velocity (DRF), and force–velocity slope (FV). Results: CMJ remained essentially unchanged in both age categories. Sprint performance improved over time, with the pattern of adaptation generally favouring RST for force-oriented sprint mechanical variables (F0, Pmax and RFpeak), whereas improvements in Vmax were observed in both groups. In the Youth category, the FV slope differed between groups post-test (p = 0.002). Overall, resisted sprint training tended to produce larger improvements in acceleration-oriented mechanical qualities, while non-resisted sprint training was associated with more velocity-oriented adaptations. Conclusions: Low-volume resisted sprint training using a sled load of ~20% body mass was associated with more favourable adaptations in force-oriented sprint mechanical variables, whereas non-resisted sprint training tended to favour velocity-oriented characteristics. CMJ performance remained unchanged in both groups. These findings should be interpreted cautiously given the small age-stratified subgroup sizes and the single-club nature of the study. Trial registration: This study was retrospectively registered at ClinicalTrials.gov (NCT07418892). Full article

The Huainan Mining Area features extensively developed, fragmented-soft and low-permeability coal seams, characterized by low porosity and permeability, complex geological structures, and significant difficulty in coalbed methane (CBM) drainage. Horizontal wells with staged fracturing in the coal seam roof have become a key method for regional gas control. To further enhance the volume fracturing stimulation effect and single-well gas production, this study targets the horizontal well group in the roof of the No. 8 coal seam in the Huainan Mining Area as the research object. A saturated volume fracturing technology for horizontal wells in the coal seam roof, centered on the concept of a high pump rate (18–20 m³/min) and a high proppant volume (>250 m³/stage), is proposed. This study investigates the fracture propagation mechanisms and fracturing parameter optimization of this technology, and conducts engineering application to verify its stimulation effect. Increasing the fracturing pump rate improves the proppant-carrying capacity of the fracturing fluid, successfully enabling high-rate and high-volume proppant placement. Optimization of the perforation parameters—12 holes per m per cluster and a cluster spacing of 15–25 m—utilizes high perforation friction and moderate stress interference to promote balanced initiation and propagation of multiple fractures within a stage. The optimized ‘saturated’ injection mode, with a single-stage fluid volume exceeding 2400 m³, a single-stage proppant volume exceeding 250 m³, and a maximum sand ratio exceeding 20%, combined with a multi-size proppant mixture, enables full propping of both main and branch fractures. Microseismic monitoring shows that the hydraulic fracture extension length increased by approximately 50% compared to conventional wells, significantly enlarging the stimulated reservoir volume (SRV). Saturated fracturing achieved stable gas production of 2000 to 3000 m³/d, with average production ramp-up rates of 21.47–26.40 m³/d (five times higher than the 5.34 m³/d of the conventional well), and the stable plateau period was notably extended from 36 days to over 150 days. The saturated volume fracturing technology proposed in this study provides an important reference for efficient CBM extraction and surface gas control in mining areas with similar geological conditions. Full article

The rapid transition toward renewable energy requires transparent and spatially explicit methods for identifying suitable photovoltaic (PV) development areas. This study develops a geospatial artificial intelligence (GeoAI) decision-support framework for PV site suitability assessment in Rajasthan, India. Eleven harmonized predictors were used: global horizontal irradiance (GHI), photovoltaic power output (PVOUT), temperature, wind speed, aerosol optical depth (AOD), elevation, slope, albedo, land use/land cover (LULC), distance to roads, and distance to power lines. Reference labels were generated from an explicit rule-derived suitability index, class thresholds, and exclusion logic; therefore, the machine-learning task was to reproduce a transparent suitability framework rather than to predict observed PV yield or project-level performance. Extreme Gradient Boosting (XGBoost) was compared with simpler baseline models, evaluated using random and spatial-block validation, and interpreted using SHapley Additive exPlanations (SHAP). Independent overlays with known solar-installation records, presence-background robustness testing, and uncertainty/sensitivity analysis were used to examine spatial plausibility, spatial autocorrelation, deterministic label effects, and parameter uncertainty. The resulting outputs include pixel-level suitability zones, contiguous candidate polygons, district-level capacity-oriented summaries, and planning-priority classes. The framework is intended as a risk-aware regional screening tool: high model agreement indicates consistency with the constructed suitability labels, while final project decisions require parcel-scale land, grid, environmental, social, and economic assessment. Full article

To scientifically explore the vehicle capacity characteristics of circular earthwork transportation routes in water conservancy projects, this paper takes the second-phase project of the Huaihe River Sea Entrance Channel as the research background. Key influencing factors such as road conditions, vehicle performance parameters, safe car-following distance, and earthwork loading–unloading duration are comprehensively considered, and a cellular automaton simulation model is constructed. Horizontal comparative verification is carried out with the Intelligent Driver Model, System Dynamics model, and field measured data to verify model accuracy. The results reveal that the cellular automaton (CA) model yields a total vehicle transport trip count of 606, with a MAPE of 0.66% when compared against the field-measured average of 602 trips. The simulated average travel speed reaches 16.71 km/h, corresponding to a MAPE of 2.89% relative to the field measurement of 16.24 km/h. The error metrics of these two indicators are markedly lower than those derived from alternative models. Due to differences in modeling paradigms and applicable mechanisms, the three models exhibit distinct characteristics in simulation performance. Among them, the cellular automaton model is more suitable for the circular earthwork transportation scenario of this study, which can accurately reflect the coupling characteristics of microscopic traffic behaviors such as multi-route confluence and node queuing, and has high consistency with actual engineering operation. Sensitivity analysis indicates that improving earth loading efficiency and reasonably arranging excavator quantity can significantly enhance the overall transportation efficiency. The modeling ideas and simulation analysis method adopted in this paper are not only applicable to the specific engineering scenario, but also can be extended to similar water conservancy earthwork transportation and large-scale engineering logistics transportation fields. It can provide theoretical basis and engineering reference for earthwork scheduling optimization and quantitative calculation of traffic capacity in water conservancy projects. Full article

Localized failures of structural components can lead to serious social, economic, and environmental consequences, such as the collapse of an entire structure or part of it. Therefore, it is important to thoroughly investigate and justify the acceptance criteria for these components, taking into account their performance in extreme conditions. However, the scientific literature lacks a systematic analysis of how various factors can affect the resistance of structures and influence acceptance criteria under extreme conditions. Therefore, this study investigates the typical substructures of reinforced concrete frame buildings in areas that are potentially prone to local collapse. To assess their resistance and structural robustness, an analytical model has been developed. The results of 22 tests on typical substructures of monolithic and precast frames, reported in various research studies, were used to validate this model. Further, this analytical model was used to conduct a parametric study on the impact of various factors on the performance of substructures under extreme conditions. These factors included the depth-to-span ratio of the beam, the strength of the bond between the steel reinforcement and the concrete, the stiffness of the horizontal bracing within the substructure, and the proportion of the effective depth to the total depth of the beam section. It has been found that the ultimate rotation angle in the plastic hinge of beams increases as the ratio of the beam’s cross-sectional depth to the span increases. An increase in the bond strength between the reinforcement and concrete leads to a decrease in the ultimate rotation angles in the plastic hinge at the flexural and arch stages of resistance and, in some cases, to reinforcement rupture without transitioning to the catenary stage of resistance. A decrease in the ratio of the effective depth of the beam section to its overall depth leads to an increase in the load-bearing capacity at the catenary stage of 19%. Full article

Optimizing the structural stability of foundations is challenging in modern geotechnical engineering. This study investigated the mechanism of geocell-reinforced foundations through discrete element modeling based on transparent soil model tests. A three-dimensional particle flow code (PFC^3D) model was developed to investigate the micromechanical soil–geocell interactions in both unreinforced and geocell-reinforced foundations under strip loading. Particle displacement, contact force distribution, and structural deformation within the foundation system were analyzed to quantify the performance of geocell reinforcement. The results show that geocell inclusion enhances structural performance by 2.1 times compared to an unreinforced foundation, increasing the bearing capacity from 60.6 to 126.8 kPa at a defined bearing capacity criterion. The geocell walls act as rigid physical boundaries that microscopically intercept the lateral migration and horizontal extrusion of soil particles. The kinematic trajectories of soil particles beneath the loading plate are forced into a downward realignment, decreasing the displacement vector rotation angle from 42° in the unreinforced soil to 27° in the reinforced soil and effectively mitigating the heave of adjacent surfaces. Furthermore, the quasi-rigid three-dimensional network completely interrupts the continuous steep contact force chains inherent in unreinforced foundations. Concentrated vertical stresses are converted into horizontal components through interfacial friction and mechanical interlocking, resulting in the lateral redistribution of the applied load by a distance of approximately 0.06 m. The geocell–soil composite considered as a flexible raft foundation extends load dispersion and reduces average subsoil pressure. A coupled tension and compression stress state in the horizontal plane is developed within the geocell structure. Forces are channeled along rigid paths by elevated bending moments and stress concentrations at the cell junctions. These findings provide micromechanical insights into the performance of geocell-reinforced-foundation systems. Full article

To investigate the influence of dry connection methods on the seismic behavior of assembled composite walls, four assembled composite walls were designed and tested. Various dry connection techniques were adopted for the horizontal interfaces, namely sleeve grouting connection, welding connection, box connection, and bolted connection. The failure process, failure mode, bearing capacity, rigidity, steel bar strain, and energy absorption performance of the specimens were investigated through quasi-static cyclic loading tests. The results indicate that all types of connectors can effectively transfer loads and satisfy the conceptual design principle of “strong joint and weak component”. The damage evolution of the specimens is essentially identical, and the limiting drift angles all exceed 1/90. In addition, the shear resistance of the specimens with different connection methods is preliminarily analyzed and estimated. Full article