Search Results (2,172)

Goring during bullfights represents a penetrating trauma with a high risk of muscular, vascular, and vital injuries. Despite its frequency and severity, limited information is available on the immediate physiological response of the bullfighter at the moment of trauma. This case report describes the heart rate of a professional bullfighter who was gored during a bullfight, underwent surgery, and returned to fight the next bull. During the first fight, the bullfighter suffered a penetrating goring wound to the inner side of the lower third of his right thigh and a fracture of the ninth rib with intercostal rupture. Upon standing, he experienced a marked drop in heart rate and a feeling of loss of consciousness, possibly associated with vasovagal presyncope. He was transferred to the infirmary in hemodynamically stable condition. He was given local anesthesia, followed by surgical exploration, cleaning, and layered closure of the wound. After surgery, the bullfighter experienced a gradual increase in heart rate upon standing, possibly due to postural changes and postoperative sympathetic activation. He then returned to the bullring to resume activity. This case report highlights a possible vasovagal response to penetrating trauma, which may be relevant for trauma care, as a vasovagal or parasympathetic-predominant autonomic response could influence early clinical assessment. Full article

We study a hybrid stochastic SIS co-infection model for two primary strains and a co-infected class with Crowley–Martin incidence, Markovian regime switching, and Lévy jumps. The model is a four-dimensional regime-switching Lévy-driven SDE system with state-dependent diffusion and jump coefficients. Under natural integrability conditions on the jumps and a mild structural assumption on removal rates, we prove uniform high-order moment bounds for the total population, establish pathwise sublinear growth, and derive strong laws of large numbers for all Brownian and Lévy martingales, reducing the long-time analysis to deterministic time averages. Using logarithmic Lyapunov functionals for the infective classes, we introduce four noise-corrected effective growth parameters ${\lambda }_1,\dots ,{\lambda }_4$ and two interaction matrices $A,B$ that encode the combined impact of Crowley–Martin saturation, regime switching, and jump noise. In terms of explicit inequalities involving ${\lambda }_k$ and the entries of $A,B$, we obtain sharp almost-sure criteria for extinction of all infectives, persistence with competitive exclusion, and coexistence in mean of both primary strains, together with the induced long-term behaviour of the co-infected class. Numerical simulations with regime switching and compensated Poisson jumps illustrate and support these thresholds. This provides, to our knowledge, the first rigorous extinction-exclusion-coexistence theory for a multi-strain SIS co-infection model under the joint influence of Crowley–Martin incidence, Markov switching, and Lévy perturbations. Full article

The aerodynamic performance of unmanned aerial vehicles (UAVs) with non-conventional geometries is a growing area of interest, particularly for improving stability and maneuverability. This study investigates the influence of the dihedral angle on the aerodynamic behavior and overall performance of drones configured in an X-wing layout. Four configurations with dihedral angles of 0°, 15°, 30°, and 45° were analyzed to assess how varying the wing inclination affects flight characteristics. Computational fluid dynamics (CFD) simulations were conducted to evaluate the aerodynamic forces and moments acting on each configuration under controlled conditions. Following the aerodynamic analysis, a performance assessment was carried out to determine the implications of each dihedral angle on parameters such as range, endurance, rate of climb, angle of climb or turn rate. The results indicate that increasing the dihedral angle can enhance maneuverability but may lead to trade-offs in aerodynamic efficiency, particularly at higher angles. The 15° and 30° configurations demonstrated a favorable balance between maneuverability and performance. These findings provide insight into the design optimization of X-wing UAVs and highlight the potential of dihedral angle tuning as a means to tailor drone behavior for specific operational needs. Full article

The deltoid ligament (DL) is the primary stabilizer of the medial ankle; however, a limited understanding of the functional roles of its various bundles hinders rational surgical decision-making. This study aims to investigate the roles of individual DL bundles in maintaining ankle stability and articular contact pressure and thus seeks to guide decisions on whether reconstruction is required for specific injuries. A validated finite element foot model was used to simulate isolated and multiple deficiencies in the DL bundle. The articular displacements, rotations, and peak talar cartilage contact pressure were evaluated under anterior drawer force and under internal–external rotation, eversion, and plantarflexion–dorsiflexion moments. Compared with the intact model, anterior tibiotalar ligament (ATTL) deficiency resulted in the greatest anterior drawer displacement (increase: 29%). Talonavicular ligament (TNL) deficiency caused the largest internal–external rotation and plantarflexion (increases in external rotation: 69%; in internal rotation: 10%; in plantarflexion: 32%). Tibiocalcaneal ligament (TCL) deficiency caused the largest eversion (increase: 93%). Deep posterior tibiotalar ligament (dPTTL) deficiency caused the largest dorsiflexion (increase: 68%). The maximum talar cartilage contact pressure occurred in the TNL-deficient model under the plantarflexion condition. In conclusion, individual DL bundles exhibit specific functions in terms of controlling multidirectional ankle stability—the ATTL, TNL, TCL, and dPTTL are the primary stabilizers for anterior translation, rotation/plantarflexion, eversion, and dorsiflexion, respectively. These findings provide a biomechanical rationale for personalized surgical strategies. When comprehensive DL reconstruction is not feasible, clinicians can prioritize the reconstruction of specific bundles according to the patient’s instability severity and functional demands across degrees of freedom. Full article

Time-dependent reliability analysis (TRA) is essential for the life-cycle risk assessment of engineering systems. However, existing TRA methods often require extensive statistical data or computationally expensive surrogate models, which limit their applicability under sparse sampling conditions. This paper presents a novel TRA framework that integrates probability-weighted moments (PWMs), a maximum entropy-based quantile function, and a fourth-order moment saddle-point approximation (FMSPA). The PWM method provides asymptotically unbiased moment estimates for small samples, while the maximum entropy-based quantile function directly computes the first four central moments of random variables. Subsequently, the FMSPA method is extended for use in TRA to efficiently evaluate the cumulative failure probability at each time point. The effectiveness of the proposed method is demonstrated through three engineering examples. The results indicate that the method delivers accurate and efficient TRA under sparse sampling conditions. Full article

Operational expenditure in wind farms is heavily influenced by unplanned maintenance, much of which stems from undetected rotor system faults. Although many fault-detection methods have been proposed, most remain confined to laboratory test. Blade-root bending-moment measurements are among the few techniques applied in the field, yet their reliability is limited by strong sensitivity to varying operational and environmental conditions. This study presents a data-driven rotor health-monitoring framework that enhances the diagnostic value of blade bending-moments. Assuming that the wind speed profile remains approximately stationary over short intervals (e.g., 20 s), a machine-learning model is trained on bending-moment data from healthy blades to predict the incident wind-speed profile under a wide range of conditions. During operation, real-time bending-moment signals from each blade are independently processed by the trained model. A healthy rotor yields consistent wind-speed profile predictions across all three blades, whereas deviations for an individual blade indicate rotor asymmetry. In this study, the methodology is verified using high-fidelity OpenFAST simulations with controlled blade pitch misalignment as a representative fault case, providing simulation-based verification of the proposed framework. Results demonstrate that the proposed inverse-modeling and cross-blade consistency framework enables sensitive and robust detection and localization of pitch-related rotor faults. While only pitch misalignment is explicitly investigated here, the approach is inherently applicable to other rotor asymmetry mechanisms such as mass imbalance or aerodynamic degradation, supporting reliable condition monitoring and earlier maintenance interventions. Using OpenFAST simulations, the proposed framework reconstructs height-resolved wind profiles with RMSE below 0.15 m/s (R² > 0.997) under healthy conditions, and achieves up to 100% detection accuracy for moderate-to-severe pitch misalignment faults. Full article

This manuscript examines how distinct epistemic attitudes toward singularity and generality have been articulated in medical writing across different historical contexts, offering a conceptual and meta-historical analysis of two enduring genres in biomedical literature: the individualized case report and the systematically aggregated clinical trial. Hippocratic case narratives are considered as a particularly lucid articulation of a mode of inquiry that privileges detailed observation of individual patients, while medieval Aristotelian natural philosophy exemplifies a contrasting emphasis on regularity, intelligibility, and general explanation. Renaissance medical and philosophical traditions are treated as a mediating moment in which attention to anomaly, wonder, and singularity was explicitly re-legitimized within learned medicine. These historically situated articulations are not presented as stages in a progressive narrative, but as recurrent epistemic orientations that are repeatedly reconfigured under different theoretical, institutional, and technological conditions. The paper argues that the tension between attention to exceptional cases and the pursuit of generalizable knowledge continues to structure modern biomedical writing, where case reports remain essential for identifying rare, novel, or anomalous phenomena, while clinical trials formalize strategies for producing reproducible, population-level evidence. Full article

On 18 March 2025, a moderate earthquake with moment magnitude Mw 4.2 struck the Basilicata region in Southern Italy. The event occurred at 09:01:25 UTC with an epicentre located approximately 4 km northeast of the city of Potenza (PZ). The earthquake was clearly felt across the urban area and followed by a sequence of low-magnitude aftershocks. A few hours after the main shock, researchers from the University of Basilicata installed a temporary structural monitoring network to check the structural conditions of several buildings located in Potenza. This installation enabled the acquisition of accelerometric recordings of several aftershocks, providing a valuable dataset for preliminary observations on structural seismic response. The monitoring campaign focused on two adjacent twin buildings with similar geometry and structural layout but different seismic design strategies: one conventionally fixed at the base and the other equipped with seismic base isolation made by rubber bearings. Comparative analyses revealed distinct differences in dynamic response. The results highlight the need for refined regulatory tools to address near-epicentral conditions, particularly potential dynamic interactions among the vertical ground-motion component, the vertical vibration frequencies of the superstructure, and floor-system resonance. While not critical for ultimate limit states, these effects may influence comfort and performance in operational and damage limit states. Full article

Heterocyclic organic compounds, namely 1,1′-methylenebis(pyridinium) bromide (Inhibitor I) and 1,1′-ethylenebis(pyridinium) bromide (Inhibitor II), were investigated as corrosion inhibitors for mild steel in acidic wastewater (0.5 M H₂SO₄). The inhibition performance was evaluated using gravimetric weight-loss measurements and electrochemical techniques. The results show that increasing inhibitor concentration significantly reduces the corrosion rate and enhances the inhibition efficiency, reaching maximum values of 90.42% for Inhibitor I and 87.85% for Inhibitor II at 7.5 × 10⁻³ M. This improvement is associated with a notable decrease in corrosion current density, indicating adsorption of inhibitor molecules at the steel/electrolyte interface. Adsorption studies reveal that both inhibitors follow the Langmuir adsorption isotherm, suggesting a mixed physisorption–chemisorption mechanism. Density functional theory (DFT) calculations and molecular dynamics simulations provide qualitative insight into the adsorption behavior, emphasizing the contribution of heteroatoms and π-electron systems to inhibitor–metal interactions. Overall, Inhibitor I exhibits superior inhibition performance, which can be attributed to its higher molecular reactivity, lower HOMO–LUMO energy gap, and higher dipole moment. The combined experimental and theoretical results demonstrate that the investigated compounds exhibit high corrosion inhibition efficiency under the studied conditions for mild steel in acidic wastewater environments. Full article

Distributed-drive commercial vehicles are prone to skidding or rolling over when operating on low-friction roads or negotiating tight curves. To address this issue, this paper proposes a control strategy based on Adaptive Model Predictive Control (AMPC) to coordinate yaw and roll stability of distributed-drive commercial vehicles. By analyzing the improved $\beta -\dot{\beta }$ phase-plane boundary and the roll stability threshold, this study identifies the yaw rate, sideslip angle, and predicted lateral load transfer rate (PLTR) as key indicators for vehicle stability assessment. The AMPC controller employs these metrics to dynamically adjust the control weights associated with yaw and roll stability in real time, thereby calculating the required additional yaw moment, which is applied through optimal torque distribution among all four wheels to achieve coordinated control. Finally, experiments are conducted on a Simulink-TruckSim co-simulation platform to assess the performance of AMPC. Compared with the conventional MPC method, the proposed approach achieves obvious improvements in both roll and yaw stability under sinusoidal and fishhook operating conditions. Full article

The resummation of Stieltjes series remains a key challenge in mathematical physics, especially when Padé approximants fail, as in the case of superfactorially divergent series. Weniger’s $\delta$-transformation, which incorporates a priori structural information on Stieltjes series, offers a superior framework with respect to Padé. In the present work, the following fundamental question is addressed: Is the $\delta$-transformation, once it is applied to a typical Stieltjes series, capable of correctly simulating the branch cut structure of the corresponding Stieltjes function? Here, it is proved that the intrinsic log-convexity of the Stieltjes moment sequence (guaranteed via the positivity of Hankel’s determinants) allows the necessary condition for $\delta$ to have all real poles to be satisfied. The same condition, however, is not sufficient to guarantee this. In attempting to bridge such a gap, we propose a mechanism rooted in the iterative action of a specific linear differential operator acting on a class of suitable auxiliary log-concave polynomials. To this end, we show that the denominator of the $\delta$-approximants can always be recast as a high-order derivative of a log-concave polynomial. Then, on invoking the Gauss–Lucas theorem, a consistent geometrical justification of the $\delta$ pole positioning is proposed. Through such an approach, the pole alignment along the negative real axis can be viewed as the result of the progressive restriction of the convex hull under differentiation. Since a fully rigorous proof of this conjecture remains an open challenge, in order to substantiate it, a comprehensive numerical investigation across an extensive catalog of Stieltjes series is proposed. Our results provide systematic evidence of the potential $\delta$-transformation ability to mimic the singularity structure of several target functions, including those involving superfactorial divergences. Full article

Dense and complex underground structures impose stringent requirements on shield tunneling. In the close-proximity construction of super-large-diameter shield tunnels, challenges may arise, including adverse impacts on the normal operation of existing structures, as well as difficulties in ensuring the bearing capacity and deformation control of these structures during excavation. This study, based on the stratigraphic conditions of the Chengdu area, employs FLAC3D 7.0 version software to simulate the section where the Shuanghua Road Tunnel underpasses both Metro Line 10 and the Chengdu-Guiyang High-Speed Railway. The main conclusions are as follows: (1) Tunnel underpassing induces uneven settlement in the metro tunnel, with a maximum settlement reaching 47.7 mm. The settlement trough exhibits a twin-peak morphology during dual-line construction. When a single super-large-diameter tunnel line crosses the existing structural cluster, the maximum settlement is located directly above the crossing point. During dual-line crossing, the maximum settlement shifts towards the midpoint between the two new tunnel lines. (2) As the left line of the new tunnel approaches the existing structure, the cross-sectional deformation of the existing structure is “pulled” towards the direction of the excavated new tunnel. After the new left line moves away, the cross-sectional deformation gradually recovers to a bilaterally symmetrical state. (3) The tunnel cross-section undergoes dynamic “compression-tension” convergence changes during the construction process, with a maximum longitudinal tensile convergence of −1.28 mm. (4) During the underpassing of the existing structural cluster by the super-large-diameter tunnel, the maximum torsion angle is approximately −0.016°, occurring at the moment when the shield machine head first passes directly beneath, located directly above the new tunnel. The torsion angle of the existing structure is greatest during the first underpassing event, and the maximum torsion angle during the second underpassing is lower than that during the first. This study reveals the composite deformation mode of “settlement-convergence-torsion” during the underpassing of existing structural clusters by super-large-diameter shield tunnels, providing a theoretical basis for risk control in similar adjacent engineering projects. Full article

Frequency domain methods used in electromagnetic analyses, such as the Method of Auxiliary Sources (MAS) and the various Moment Methods (MoM), share many similarities but have notable differences in terms of numerical stability, accuracy, and computational cost. Computational cost differs from algorithmic complexity, which is easier to define. Consequently, it is rarely analyzed systematically in numerical studies. To this end, this work deals with the canonical problem of electromagnetic scattering from an externally excited circular cylinder of infinite conductivity and applies both MAS and MoM in order to assess their solutions and behaviors from the aforementioned perspectives. This problem is solved by meticulously applying MAS and two popular variants of MoM to achieve comparable stability and accuracy. Then, the methods are compared in terms of the associated computational cost, not only in solving the ensuing matrix equations, but also in computing the near and far fields at a large number of points. Full article

Aiming at analyzing the load characteristics and friction torque of triple-row hub bearings for new energy vehicles, this work established a comprehensive theoretical and experimental methodology for predicting the internal load distribution and friction torque. Firstly, considering the preload effect via an initial negative clearance, deformation coordination and force balance equations for the triple-row bearing under axial load were formulated, to analyze the external loads under various driving conditions. Based on contact deformation theory, a quasi-static model was developed to combine radial, axial, and moment loads. The Newton–Raphson iterative algorithm was employed to solve the ball load distribution equations, and the correctness was verified by using the finite element method. Furthermore, accounting for the elastic hysteresis, differential sliding, and spin sliding, the theoretical models for friction torque components were established, to investigate the influence of structural parameters and the total friction torque under different driving conditions. Finally, to confirm the effectiveness and the precision of the model, a finite element simulation and experimental measurements of friction torque were conducted, respectively, which showed good agreement with theoretical calculations. The main innovations include proposing a mechanical modeling method for triple-row hub bearings that accounts for preload effects, and establishing an integrated friction torque analysis model applicable to multiple driving conditions. This work provides theoretical support and a methodological foundation for the design of next-generation hub bearings for new energy vehicles. Full article

Top-and-seat angle connections (TSACs) exhibit inherently asymmetric and nonlinear moment–rotation behavior, which can significantly influence the global response of steel frames subjected to combined gravity and lateral loading. In this study, a three-dimensional finite element model of an unstiffened TSAC is developed and validated against experimental moment–rotation data from the literature under monotonic loading conditions. The validated model is then used to investigate the influence of key geometric parameters, including top angle thickness, bolt diameter, and beam depth, on the connection’s moment–rotation response in both positive and negative bending directions. Subsequently, the monotonic connection behavior is incorporated into nonlinear static analyses of steel portal frames to examine the effects of asymmetric connection response and moment reversal on frame-level stiffness degradation and capacity. A practical SAP2000 modeling workflow is proposed in which the finite element-derived monotonic moment–rotation curves are implemented using zero-length rotational link elements, allowing combined consideration of material, geometric, and connection nonlinearities at the structural level. The comparisons between Abaqus and SAP2000 results demonstrate consistent frame-level responses when identical monotonic connection characteristics are employed, highlighting the ability of the proposed workflow to reproduce detailed finite element predictions at the structural analysis level. The results indicate that increasing top angle thickness, bolt diameter, and beam depth enhances the lateral stiffness and base shear resistance of steel frames. Positive and negative bending directions are defined consistently with the applied gravity-plus-lateral loading sequence. Full article