Search Results (53)

Ground deformations induced by underground mining significantly affect the geometric condition and serviceability of buildings located in mining areas. Conventional assessments are commonly based on ground deformation indicators, which do not necessarily reflect the actual structural response. This study presents a terrestrial laser scanning (TLS)-based methodology for assessing the three-dimensional deformation of an eleven-storey residential building located in the Legnica–Głogów Copper District (LGCD), Poland. The analysis was performed using a high-density point cloud acquired from ten scanning positions. Following registration and filtering, building geometry was reconstructed and corner positions were determined from 123 horizontal cross-sections. Horizontal displacements, tilt profiles, and rotation about the vertical axis were subsequently analysed within a local coordinate system. The results revealed pronounced spatial variability in both displacement magnitude and direction. The maximum horizontal displacement reached approximately 0.18 m, corresponding to a local tilt of 5.9 mm/m. Corner displacements at the highest common observation level ranged from 8.6 mm to 178.3 mm, indicating that the observed geometry is inconsistent with a simple rigid-body model subjected to uniform tilting. Analysis of geometric changes with height further identified an overall increase in torsional rotation with height, accompanied by local variations. Comparison of TLS-derived geometry with a theoretical mining-induced ground deformation model showed that the measured structural response does not directly reproduce the underlying ground deformation pattern. The largest discrepancies occurred along the building longitudinal axis, indicating that structural stiffness and soil–foundation–structure interaction significantly modify the transfer of ground movements to the superstructure. These results demonstrate the capability of TLS for detailed assessment of mining-affected buildings and provide quantitative insight into the relationship between ground deformation and actual structural response. Full article

Background/Objectives: Age may influence myocardial recovery after acute myocardial infarction (AMI) beyond changes in left ventricular ejection fraction (LVEF). We investigated age-related patterns in ischemic delay, admission biomarkers, biventricular function, myocardial deformation, and exploratory patterns of prescribed heart failure guideline-directed medical therapy (HF-GDMT) classes after primary percutaneous coronary intervention (PCI). Methods: This prospective frequency-matched cohort study included 90 AMI patients treated with primary PCI, stratified into younger (25–44 years; n = 30) and older (≥45 years; n = 60) groups. Clinical data, ischemic time, cardiac biomarkers, serial echocardiography at baseline, 6, and 12 months, and HF-GDMT intensity were analyzed. Results: Older patients had longer pain-to-balloon time (720 [480–1230] vs. 540 [420–660] min; p = 0.021), higher hs-cTnI (p = 0.045), and higher NT-proBNP (4776 [3013–5952] vs. 833.5 [95.7–1939.5] pg/mL; p < 0.001). Baseline and 12-month LVEF were similar between groups. Younger patients showed greater 12-month global longitudinal strain (GLS) improvement (−3.7 [−5.1 to −1.9] vs. −2.3 [−3.0 to −1.3] percentage points; p = 0.002), despite comparable absolute GLS. In exploratory post hoc analyses, prescribed HF-GDMT drug-class count showed an association with LVEF change primarily in older patients, who also had significantly lower baseline LVEF (ρ = 0.59; p < 0.001). Conclusions: In this prospective exploratory cohort, 12-month conventional systolic recovery assessed by LVEF and absolute GLS was comparable between age groups after primary PCI. However, the older comparator group had longer ischemic delay and higher admission biomarkers reflecting cardiomyocyte injury and myocardial wall stress, while younger patients showed greater longitudinal GLS improvement over time. These findings suggest that age-stratified recovery after AMI is better characterized by ischemic timing, baseline biomarker profile, and deformation trajectory than by LVEF alone. Because infarct size was not directly quantified, admission biomarker differences should not be interpreted as evidence of larger infarcts. Full article

This study investigates the shear behavior and failure mechanisms of innovative hybrid structural beams fabricated by filling pultruded glass fiber-reinforced polymer (GFRP) box sections with waste rubber-reinforced concrete (RuC). Environmentally friendly concrete was produced by replacing natural aggregate with recycled tire-rubber fibers at proportions of 0%, 5%, 10%, and 15%. Twelve hybrid beam specimens were tested to evaluate the synergistic effects of rubber content and stirrup spacings of 16, 20, and 27 cm on shear capacity, ductility, and crack propagation. The experimental results revealed that the reference specimen (S16-0%) exhibited the maximum shear capacity of 154.41 kN and a brittle failure mode, while an increase in rubber content to 15%, combined with wider stirrup spacing, significantly reduced this capacity to a minimum of 96.89 kN (S27-15%). However, the 5% rubber replacement ratio achieved an optimal performance balance by preserving sufficient load-carrying capacity while enhancing flexural deformation and ductility, particularly in specimens with 16 cm stirrup spacing. Damage analysis demonstrated that longitudinal splitting cracks initiated in the mid-span tension zone at the bottom of the pultruded profiles, with final localized damage concentrated at the geometric corners of the box section. Crucially, the outer pultruded GFRP profiles provided substantial structural confinement, effectively mitigating the strength loss associated with high rubber incorporation and controlling the progression of sudden brittle failure. These findings highlight that combining pultruded GFRP profiles and optimized RuC offers a structurally viable and sustainable solution for modern infrastructure applications. Full article

Determining the optimal timing for support installation is of critical importance to the stability of surrounding rock in inclined mine roadways. Existing expressions for the longitudinal deformation profile (LDP) commonly overlook the coupled effects of spatial parameters and geomechanical parameters in inclined roadways. In this study, the LDP expression for a circular inclined roadway under three-dimensional in situ stress conditions is firstly derived analytically. Subsequently, the coupled influence of spatial and geomechanical parameters on the LDP is investigated using FLAC3D numerical simulations. Finally, building upon the work of Unlu and Gercek, a modified LDP formula tailored to circular inclined roadways is proposed. The results indicate the following: (1) The parameters exerting a significant influence on the LDP shape can be ranked in descending order of importance as cohesion, internal friction angle, β, and α. Parameter α affects the LDP curve within the range of X/R = −6 to 6. As α increases from 5° to 35°, the displacement release coefficient at the tunnel face (u₀*) drops sharply from 15.830% to 5.107%. In contrast, β, cohesion, and internal friction angle influence the LDP within the range of X/R = −6 to 9. Specifically, as β varies from 0° to 90°, u₀* decreases from 15.830% to 8.920%; as cohesion increases from 2 MPa to 3.5 MPa, u₀* declines from 18.80% to 14.38%; and as the internal friction angle rises from 20° to 35°, u₀* drops from 18.40% to 12.08%. (2) Poisson’s ratio, the axial lateral pressure coefficient, the horizontal lateral pressure coefficient, and the elastic modulus exhibit relatively minor effects. Poisson’s ratio primarily influences the displacement release coefficient in the vicinity of the excavation face, within the range of X/R = −1 to 3. As Poisson’s ratio increases from 0.2 to 0.35, u₀* decreases from 15.83% to 13.54%. Although its effect at the tunnel face is modest, it should not be disregarded. (3) Validation against existing LDP formulas and field data demonstrates that the proposed modified formula more effectively characterizes the spatiotemporal evolution of displacement release in the surrounding rock of circular inclined roadways, thereby providing a more reliable reference for determining the optimal support installation timing and optimizing the support design of inclined shafts. Full article

To reveal the differences in stratum response among different environmental sections and the influences of key construction parameters on deep soil deformation during river-crossing double-line shield tunneling, the paper takes the East Genshan Road River-Crossing Tunnel as the engineering case, and systematically investigates the stratum responses of the onshore and riverbed sections as well as the effects of construction parameters via field monitoring, measured construction parameter data and three-dimensional finite element simulation based on ABAQUS. The simulation results suggest that, compared with the onshore section, the riverbed section may present larger cumulative displacement, more intense deep soil response and a wider influence range of transverse settlement under the investigated high-water-pressure and saturated soft-soil conditions. These differences are more reasonably interpreted as the combined effects of burial depth, stratum composition, mechanical properties, hydraulic boundary conditions, surface boundary constraints and overburden conditions. Among these factors, the high-water-pressure and saturated soft-soil environment may contribute to the enhanced disturbance diffusion and cumulative deformation response observed in the riverbed section. The longitudinal displacement evolution of the riverbed section presents obvious stratified transmission characteristics, and its transverse settlement trough shows a typical double-peak W-shaped distribution with larger peak values, wider trough profile and slower far-field attenuation. The single-factor parametric analysis suggests that, within the investigated parameter ranges, cutterhead torque produced the largest absolute settlement variation, followed by total shield thrust and tunneling speed. The results of this study can provide a reference basis for settlement control and construction parameter optimization of river-crossing double-line shield tunneling in high-water-pressure and saturated soft soil strata. Full article

Ocular biomechanics may contribute to the variability of structural and functional outcomes in highly myopic eyes, but their role in myopic maculopathy remains unclear. This retrospective cohort study investigated whether in vivo corneal biomechanical parameters are associated with macular structural phenotypes and longitudinal functional changes. Fifty-four eyes with high myopia (≤−6 D; mean SE −15.6 ± 6.6 D) were evaluated at baseline and after 5.0 ± 0.1 years. Biomechanics were assessed with Corvis Scheimpflug Technology^®, macular structure was assessed with SD-OCT (6 × 6 mm), and function was assessed with Microperimeter MP-3 (CPS, dB). Foveoschisis was associated with higher A2 deformation amplitude (0.371 vs. 0.333 mm, p = 0.014) and SSI (0.986 vs. 0.827, p = 0.035). Staphyloma showed changes in the highest concavity radius (7.13 vs. 6.17 mm, p = 0.002), A1 deformation amplitude (0.150 vs. 0.132 mm, p = 0.001), and maximum deflection amplitude (1.03 vs. 1.19 mm, p = 0.013). Softer corneal parameters correlated with less functional loss, while stiffer parameters correlated with greater decline; similar trends were observed for fixation stability. These findings suggest that biomechanical profiles may vary across macular phenotypes and could be associated with functional evolution in highly myopic eyes. Full article

316LN stainless steel is widely used in critical nuclear fusion structural components due to its excellent mechanical properties and machinability. However, its high thermal expansion coefficient and low thermal conductivity promote welding distortion, while work hardening causes residual stress accumulation. Thermo-elastic–plastic finite element modeling (FEM) is the primary numerical method for predicting these effects. Yet, despite hardware advances, full-scale simulations—especially for thick plates with multi-pass welds—remain computationally expensive, hindering the balance between efficiency and accuracy. To address the inherent trade-off between welding efficiency and dimensional accuracy in multi-pass, multi-layer welding of thick-section components, this study employs MSC. Marc to develop a finite element model of a 15 mm thick butt-welded joint fabricated from 316LN stainless steel. Three distinct heat source models—instantaneous, enhanced moving, and moving element-set—are systematically implemented to simulate transient temperature fields, residual stress distributions, and welding deformation. All numerical predictions are rigorously validated against experimental measurements to comprehensively assess both accuracy and computational efficiency. Results indicate that: (i) the predicted molten pool geometries and characteristic thermal cycle profiles from all three models exhibit strong agreement with experimental observations; (ii) longitudinal residual stress distributions predicted by all models align closely with measured values; (iii) transverse residual stresses predicted by the moving element-set and enhanced moving heat sources agree well with experiments, whereas those from the instantaneous heat source show marked deviation; (iv) angular distortion predictions from the moving element-set heat source achieve over 90% conformity with experimental data, while the instantaneous heat source substantially underestimates angular distortion, and the enhanced moving heat source yields approximately 65% agreement; and (v) in terms of computational efficiency, the instantaneous heat source requires only ~40% of the computation time needed by the moving heat source. Full article

Background: Dentofacial deformities (DFDs) comprise heterogeneous sagittal, vertical, transverse, and asymmetry components, yet clinical severity is often summarized using isolated measurements. Objectives: To operationalize a reproducible composite DFD severity score and evaluate its cross-sectional associations with quality of life, function, airway-related screening indicators, and psychosocial burden. Methods: In this single-center cross-sectional study, consecutive adults assessed in an orthognathic surgery pathway underwent a prespecified 0–100 severity scoring framework integrating sagittal discrepancy (|Wits| and |ANB deviation|), vertical pattern (SN-MP angle), and asymmetry/transverse variables (chin deviation, asymmetry index, transverse discrepancy, and absolute overjet). Outcomes included the Oral Health Impact Profile-14 (OHIP-14), Orthognathic Quality of Life Questionnaire (OQLQ), FACE-Q facial appearance satisfaction scale, PHQ-9, GAD-7, STOP-Bang, functional testing, and CBCT-derived upper-airway metrics. Results: Severe DFDs had higher composite severity (62.9 ± 12.8 vs. 25.3 ± 10.9), larger sagittal discrepancy (|Wits| 6.3 ± 2.8 vs. 3.1 ± 1.8), and higher SN-MP angles (39.8 ± 7.4 vs. 34.7 ± 7.2) (all p < 0.001). Severe DFDs also had worse OQLQ (36.2 ± 6.2 vs. 24.1 ± 7.2), OHIP-14 (18.3 ± 4.2 vs. 12.4 ± 4.1), FACE-Q satisfaction (45.7 ± 10.3 vs. 67.6 ± 9.6), masticatory performance (59.4 ± 8.5 vs. 75.1 ± 7.5), and smaller airway area (126.7 ± 29.6 vs. 161.4 ± 27.7) (all p < 0.001). In multivariable logistic regression, |Wits|, SN-MP angle, asymmetry index, and lower airway area independently predicted severe status; PHQ-9 was associated with severity in unadjusted analyses but did not retain independent significance after multivariable adjustment. Model discrimination was high (AUC 0.91). Conclusions: This multidimensional severity framework captures clinically meaningful cross-sectional differences across morphologic, functional, airway-related, and psychosocial domains. Its interpretability remained stable in sensitivity analyses, but external and longitudinal validation is still required before broader implementation. Full article

Accurate assessment of tunnel lining deformations and stress distributions critically governs structural integrity, while miscalculations may trigger construction delays and budget overruns. A mechanical shell model for tunnel supports was developed, integrating the modified ellipsoid theory to analytically resolve vertical displacements and internal stresses. Numerical validation through finite element simulations confirmed model efficacy. The influence of key geometric and material parameters encompassing height-to-width ratio, burial depth, lining thickness, and elastic modulus on tunnel support displacement and stress distributions was systematically investigated. Parametric analysis revealed that vertical displacement exhibited greater sensitivity to height-to-width ratio variations compared to burial depth. Longitudinal distributions demonstrated similar trends axial force and vertical displacement, with bending moments and shear forces exhibiting analogous behavioral patterns. Transver sely, axial forces and vertical displacements adopted a symmetrical trough (U-shaped) profile, while bending moments and shear forces formed a bimodal (M-shaped) distribution with attenuated gradients near the crown region. This computational model establishes a practical analytical tool for evaluating post-support tunnel deformation and structural load distributions. Full article

To solve the problems of large deformation and poor welding quality commonly observed during the double-sided welding of Q355 thin plates, this study systematically investigated the effects of single-sided ultrasonic-assisted welding on the weld formation, microstructure, mechanical properties, and residual stresses of the plates, and compared this welding process with conventional ones. Experimental results indicate that ultrasonic assistance is associated with improved weld shape and quality, contributing to a flatter weld surface and more symmetric cross-sectional profile. In contrast to conventional welds, welds produced by single-sided ultrasonic-assisted gas metal arc welding show no obvious oxide inclusions and a reduced tendency for columnar grain growth. In a single tensile test for each welding condition, the measured tensile strength was 552 MPa for conventional welding and 575 MPa for single-sided ultrasonic-assisted gas metal arc welding. These tensile results should be interpreted as indicative trends and require replication to assess scatter and statistical significance. Furthermore, single-sided ultrasonic-assisted gas metal arc welding is associated with lower welding residual stresses, with peak stress values reduced by up to 36.23% along the longitudinal path. This technique provides an engineering reference for improving weld-quality consistency during the double-sided welding of Q355 thin plates without altering the welding specifications. Full article

Adolescence is a critical window for cardiovascular (CV) development, yet the molecular drivers of vascular adaptation to regular exercise in youth remain poorly understood. This cross-sectional study assessed vascular structure and function alongside endothelial, metabolic, and lipoprotein biomarkers in 203 healthy young athletes (aged 10–16). Vascular phenotyping included carotid intima-media thickness (IMT), pulse wave velocity, and carotid deformation indices (strain, strain rate). Circulating nitric oxide (NO), endothelin-1, free triiodothyronine (fT3), leptin, low-density lipoprotein, and high-density lipoprotein were analyzed. Associations were examined using hierarchically adjusted multivariable linear regression, mediation and moderation were tested and sex-stratified/matched analyses were conducted. While training volume was not associated with endothelial markers, leptin was correlated positively with NO and negatively with diastolic strain rate, suggesting dual vascular actions. fT3 was inversely associated with IMT, indicating a potential protective role in vascular remodeling. Lipoprotein profiles showed no independent associations with vascular parameters. Hemodynamic load, particularly systolic blood pressure, emerged as the dominant determinant of arterial stiffness. Sex-specific differences across biomarkers and vascular indices support a multifactorial model: in active youth, vascular phenotype reflects hemodynamics, body composition, and endocrine–metabolic signals more than training; longitudinal mechanistic studies should clarify causal pathways and guide individualized cardiovascular risk profiling. Full article

Structures with slender cylindrical geometries, such as subsea power cables are critical components of infrastructure systems. These structures are prone to bending deformation under load, which can ultimately cause structural failure. In this study, distributed optical fibre sensors are used to monitor the bending deformation in slender cylindrical structures. Brillouin optical time-domain reflectometry-based strain sensing was used to experimentally study three-point bending and approximately constant curvature bending of a 6 m long circular hollow section (CHS). Optical fibres were attached to the outer surface of the CHS in two different configurations: parallel to the longitudinal axis and helically wound around the CHS. Strain responses due to changing magnitudes of deformation and changing orientation of the optical fibre around the circumference of the CHS were studied. A finite element model was employed to simulate and interpret the observed strain responses. A strain response inverse analysis was conducted using the strain data obtained from the experimental study to reconstruct the deformed shapes of the CHS. Both the longitudinally aligned and helically wound fibres showed distinct strain profiles that differentiate the three-point bending and constant curvature bending behaviours. The results revealed the ability of optical fibre sensing to evaluate the type; magnitude; and orientation of the bending deformations. This fundamental understanding supports the design of sensing systems for critical cylindrical infrastructure. Full article

To address the conflicts between traditional composite slab reinforcement layouts and supports—which adversely affect construction quality and efficiency—and to fill the theoretical gap regarding end connections without projecting bars in terms of interface shear transfer, staged flexural behavior, and anchorage reliability, a grooved end-connection configuration for composite slabs is proposed. In this configuration, the longitudinal bars of the precast slab do not extend beyond the slab end. The precast slab end is formed with a recessed–protruding profile; the longitudinal bars are exposed within the groove, where additional reinforcement is pre-embedded (with a diameter not less than the area-equivalent of the longitudinal bars that would otherwise extend into the support). After erection, the additional bars are extended using straight-thread sleeves; short longitudinal bars within the groove are tied to the bottom longitudinal bars. Both the extended additional bars and the short longitudinal bars are anchored into the support by at least 5d and pass the support centerline. To evaluate the global flexural behavior of slabs with grooved end-connections, a two-span, full-scale specimen was tested under static loading. Failure characteristics, crack initiation and propagation, ultimate capacity, deflection, and ductility were investigated. The results indicate that, in the full-scale two-span test, the service load was 11.35 kN/m² (approximately 13.5% higher than the design value of 10.0 kN/m²); the midspan deflection was about L/110 (smaller than the L/50 limit); the first cracking and the pronounced nonlinearity inflection point occurred at approximately 4.25 kN/m² and ≥9.35 kN/m², respectively; and the maximum crack width was 1.66 mm. The test was terminated prior to reaching the durability and deformation limits, after which the load was increased to 22.20 kN/m². The specimen exhibited a ductile flexural failure governed by tensile reinforcement yielding; the top concrete did not crush, no shear failure was observed at the ends, and no delamination occurred at the composite interface, demonstrating favorable global flexural performance. Full article

Rotary swaging (RS) is applied for the manufacturing of bars, stepped shafts, tubes with complex internal profiles, bimetallic composites, and similar products. This process falls under the category of severe plastic deformation (SPD) methods, which produce ultrafine-grained materials that provide superior properties in service. Our study investigated the effect of cold RS on the structure, grain size, and microhardness of AISI 304 stainless steel and CK45 carbon steel. Tubular specimens were processed by RS with the purpose of obtaining conical parts with a closed end, achieving a maximum reduction of nearly 44%. Samples were taken by longitudinal sectioning along the diameter from three zones with different degrees of deformation and subjected to structural analysis using scanning electron microscopy (SEM). The investigations were complemented by microhardness measurements in the axial direction for samples of both steels. The resulting structures revealed material texturing and a continuous decrease in grain size with increasing swaging ratio. The average grain size was reduced by approximately 46% in AISI 304 steel and by around 50% in CK45 steel. The microhardness of the materials increased by about 179% for AISI 304 steel and by approximately 95% for CK45 steel. The obtained results are discussed, highlighting the effect of cold RS processing on the two steels studied. Full article

As a key component of aero transmission systems, internal splines suffer from problems of low efficiency and poor precision in traditional lapping processes due to geometric deformation and high hardness after heat treatment. To address this, this study proposes an ultrasonic vibration lapping technology, which combines the synergistic mechanism of high-frequency vibration and free abrasive particles to achieve efficient and precise machining of small-sized hardened internal splines. By establishing an abrasive grain impact trajectory model and a rolling abrasive grain material removal model, the mechanisms of micro-cutting and impact removal of abrasive particles under ultrasonic vibration are revealed. Based on the local resonance theory, a longitudinal ultrasonic vibration system is designed, and its resonant frequency is optimized through finite element modal analysis. An ultrasonic lapping experimental platform is built, and heat-treated 9310 internal spline samples are used for experimental verification. The results show that, compared with traditional manual lapping, ultrasonic vibration lapping significantly improves the tooth profile and tooth lead deviations. After measurement, following ultrasonic vibration lapping, both the total tooth profile deviation and tooth lead deviation of the internal spline meet the Grade 6 accuracy requirements specified in GB/T 3478.1-2008 Cylindrical straight-tooth involute splines (Metric Module, Tooth Side Fit)—Part 1: General. This study confirms that ultrasonic vibration lapping can effectively correct the geometric accuracy of tooth surfaces and suppress thermal damage, and provides an innovative solution for the high-quality repair of aero transmission components. Full article