Search Results (1,107)

High-precision tunnel breakthroughs depend critically on the north-seeking accuracy of maglev gyroscopes. However, external disturbances during underground construction often introduce abrupt jumps into rotor current signals, significantly reducing the orientation reliability. Existing signal-processing methods either require manually defined segmentation windows or apply identical denoising strategies to both stationary and disturbed signal intervals, resulting in limited adaptability and suboptimal denoising performance. To overcome these limitations, this study proposes an improved rotor current denoising algorithm based on the MAF-ARIMA framework by incorporating the Bayesian ensemble algorithm for abrupt change, seasonality, and trend (BEAST) and an optimized wavelet transform (OWT). First, the BEAST is employed to automatically detect the structural change point of the rotor current signal, enabling the adaptive segmentation of stationary and jump intervals without manual intervention. Subsequently, empirical mode decomposition is performed, and the OWT applies different denoising parameters to the dominant components of the stationary and jump segments according to their distinct fluctuation characteristics. Finally, moving-average smoothing is adopted to preserve the signal continuity at the segmentation boundary, while the autoregressive integrated moving average (ARIMA) model reconstructs the missing trend component of the jump interval to obtain the complete denoised signal. Comparative experiments using 12 field-collected rotor current datasets demonstrated that the proposed method reduced the standard deviation of the denoised signal by 70.96% and the absolute azimuth error by 50.36% compared with the raw signal, outperforming the optimized Hilbert–Huang transform, HSA-KS, and the original MAF-ARIMA algorithm. By introducing adaptive change-point detection and segment-specific denoising into the existing MAF-ARIMA framework, the proposed method significantly improves the adaptability and denoising performance of maglev gyro rotor current processing under complex tunnel construction environments while preserving the signal continuity and reconstruction accuracy. Full article

Wildfire spread on a large scale is heavily driven by the transport of firebrands, as it leads to short- and long-range spotting. Detailed knowledge of terminal velocity can help predict firebrand transport and therefore overall wildfire spread modelling. The current work evaluates an approach to estimating terminal velocity based on CFD simulations with a detailed firebrand shape and assesses its impact on orientation. For the selected firebrand and simulation setup, a range of terminal velocities of approximately 5 to 11 m/s is calculated. This is based on 352 RANS simulations for one particular detailed firebrand at 11 different orientations and two turbulence models, with varying inlet velocities and two mesh refinements. DES and LES turbulence models are considered as a next step for a detailed comparison with wind tunnel measurements. Full article

Biodegradable magnesium (Mg)-based implants represent a paradigm shift in orthopedic biomaterials, offering temporary mechanical support, inherent osteogenic bioactivity, and elimination of hardware removal surgery. These properties are particularly attractive for sports orthopedic applications, including anterior cruciate ligament (ACL) reconstruction, rotator cuff repair, meniscal fixation, and osteochondral fragment refixation, where young, active patients demand rapid return to function and where permanent metallic hardware poses long-term risks of stress shielding, imaging artifact, and reoperation. Despite extensive preclinical evidence demonstrating that Mg-based interference screws promote fibrocartilaginous enthesis regeneration, attenuate peri-tunnel bone loss, and achieve biomechanical fixation comparable to titanium, no human clinical trial has yet evaluated Mg fixation devices for soft-tissue reconstruction in sports medicine. Meanwhile, clinical fracture fixation data from over 468 patients across multiple trials and a meta-analysis confirm complication rates equivalent to those of titanium. This narrative review synthesizes the current evidence on Mg alloy design, surface engineering strategies, preclinical sports medicine applications, clinical translation in fracture fixation, imaging compatibility, and the remaining barriers to clinical adoption in sports orthopedic surgery. By mapping the translational gap between promising animal data and the absence of clinical sports medicine trials, this review aims to guide future research priorities and accelerate the pathway toward clinical application of Mg-based devices in sports orthopedics. Full article

The Co₄₀Fe₄₀B₂₀ alloy is a key magnetic material that combines high saturation magnetization with excellent soft magnetic properties, offering broad application prospects in fields such as spintronic devices, magnetic tunnel junctions, and tunnel magnetoresistive sensors. Hot pressing can be used to produce fine-grained, highly dense CoFeB alloys. However, there is currently a lack of systematic research on the intrinsic mechanisms by which the particle size of gas-atomized CoFeB powders and their non-equilibrium solidification microstructure regulate phase transformations, microstructural evolution, and densification behavior during hot pressing and sintering—particularly regarding the microstructural inheritance effects of powders with different particle sizes. To address this issue, this study used vacuum induction melting and gas atomization technology to prepare Co₄₀Fe₄₀B₂₀ pre-alloyed powders in three particle size ranges: <38 μm, 38–74 μm, and 74–154 μm. Under identical process parameters, corresponding bulk alloys were produced via vacuum hot-press sintering, and the effects of initial powder particle size on phase transformations and microstructural evolution in the sintered bodies were systematically investigated. Microstructural characterization revealed the complete phase evolution of the alloy from the non-equilibrium solidified powder state to the sintered equilibrium state. During hot-press sintering, the metastable (Fe,Co)₃B phase in the powder completely decomposed, transforming into a stable body-centered cubic bcc-(Fe,Co) phase and a bcc-(Fe,Co)₂B second phase. The dispersed (Fe,Co)₂B phase precipitated after sintering strongly inhibits grain boundary migration via the Zener pinning effect, effectively hindering grain growth and resulting in a uniform, fine-grained, equiaxed microstructure. In coarse powders, due to the presence of a portion of the (Fe,Co)₂B phase, this phase aggregates and grows during sintering, weakening the pinning effect and leading to abnormal grain growth. The Hall–Petch fine-grain strengthening effect resulting from grain refinement couples with and offsets the weakening of second-phase strengthening caused by second-phase coarsening, ultimately leading to sintered bodies prepared from powders of different particle sizes exhibiting similar macroscopic density and hardness properties. Full article

During the floating transportation and installation of immersed tube tunnels, the mechanical stability of the mooring system is a key factor governing construction safety. Current conditions and mooring-line arrangements are two major factors controlling the magnitude and distribution of mooring-line tensions. However, their coupled effects and the applicability of different calculation methods remain insufficiently understood. Based on a large-cross-section immersed tube tunnel project, this study employed a semi-empirical method specified in the Chinese Code for Loads on Port Engineering and a three-dimensional floating-body-mooring numerical model established in ANSYS AQWA. Multiple combinations of current velocity and direction were considered to compare the mooring-line responses under five typical arrangements corresponding to different construction stages. The effects of current conditions and mooring configurations on the magnitude, distribution, and transfer of mooring-line loads were systematically examined. The results show that current velocity is the dominant factor controlling the magnitude of mooring-line tensions, which generally increase with the square of the current velocity. Changes in current direction directly alter the principal load-bearing mooring-line group, and a current velocity of 1.5 m/s during the falling tide represents the most unfavorable current condition throughout the construction process. The mooring-line arrangement governs the spatial distribution and concentration of the line loads. During the floating transportation and mooring stages with multi-line constraints, the maximum mooring-line tensions calculated using China’s code-based method are 18.5–25.2% higher than those obtained from the numerical simulations, indicating relatively conservative predictions. In contrast, during stages with weakened constraints, such as line release and positioning in the foundation trench, the numerical model captures more pronounced local load concentration, yielding maximum tensions 19.4–28.8% higher than those predicted by the code-based method. Across all operating conditions, the maximum mooring-line tensions calculated by the code-based method and numerical model are 924 and 750 kN, respectively. This study clarifies the coupled effects of current conditions and mooring-line arrangements on mooring-load transfer and identifies the applicable scenarios of the two calculation methods. The findings provide a quantitative basis for calculation-method selection, mooring-force assessment, and construction-safety management during immersed tube tunnel installation. Full article

The ultra-wide bandgap semiconductor β-Ga₂O₃ is a promising material for next-generation optoelectronic systems and hybrid nanodevices. However, high interface state densities and anomalous trap-assisted leakage severely restrict its performance and signal transduction capabilities. To resolve these fundamental limitations, we investigated a two-dimensional h-BN interlayer to construct a high-quality heterogeneous metal/h-BN/β-Ga₂O₃ structure using experimentally calibrated Sentaurus TCAD simulations. Energy-band analysis and validated I–V simulations reveal that the low-dimensional h-BN interlayer reconstructs the interfacial barrier, suppresses interface-assisted recombination, and shifts the dominant carrier transport from thermionic emission to Fowler–Nordheim tunneling. These effects markedly reduce the interface-state density and effectively suppress the Shockley–Read–Hall recombination current, mechanisms that are critical for minimizing dark current and improving device sensitivity. After systematically examining the effects of key parameters on the electrical characteristics of this hybrid architecture, we quantify the tradeoff between threshold voltage and on-resistance using a comprehensive figure of merit. Specifically, our results indicate that maximum device efficiency is achieved only when an optimal h-BN thickness of 3.56–5.88 nm (10–17 atomic layers) is strategically integrated with the appropriate metal work function and semiconductor doping. Overall, this work suggests the potential advantage of 2D h-BN in mitigating the interfacial bottleneck of traditional β-Ga₂O₃ platforms, providing quantitative design guidelines and theoretical support for the heterogeneous integration of next-generation optoelectronic devices. Full article

Transthyretin cardiac amyloidosis (ATTR-CA) is an increasingly recognized cause of cardiac dysfunction in adults, resulting from extracellular deposition of misfolded transthyretin fibrils and progressive myocardial impairment. Clinical expression and diagnostic yield differ substantially between sexes, contributing to systematic underdiagnosis in women, who often present with subtler myocardial remodeling, heart failure with preserved ejection fraction (HFpEF)–dominant phenotypes, and nonspecific systemic manifestations that fall below conventional diagnostic thresholds, particularly in early disease stages. Female patients, particularly those with ATTRwt, tend to present at older ages and more frequently show HFpEF-dominant phenotypes and nonspecific extracardiac manifestations. Carpal tunnel syndrome (CTS) is an important extracardiac red flag for ATTR-CM, but its interpretation in women requires caution because of the high background prevalence of idiopathic CTS in the general population. Evidence also suggests sex-related differences in diastolic function, right ventricular involvement, and overall progression. Despite these biological and phenotypic distinctions, women are markedly underrepresented in trials of disease-modifying therapies, limiting conclusions about sex-specific treatment effects and leaving uncertainty about whether current pharmacologic interventions provide comparable benefit. Hormonal influences, genetic background, and age-related mechanisms, comorbidities, and diagnostic pathways may contribute to the distinctive female phenotype, but underlying mechanisms remain insufficiently defined. This narrative review examines sex-associated differences in ATTR-CA, focusing on mechanisms of underdiagnosis, principal clinical and imaging features, and implications for therapeutic response, with the goal of improving diagnostic accuracy, guiding individualized management, and ultimately enhancing outcomes for women and all affected patients worldwide in clinical practice. Full article

To address the discrepancy between the constant-power fire sources currently used in cable fire-related research and cable fire protection product testing and actual cable fires, this paper proposes a cable equivalent combustion simulation method based on electrical fault fires. The cable tunnel experiment platform was built and, based on energy equivalence, used an igniter to simulate a fault arc’s thermal effect and ignite the cable, obtaining the temperature rise characteristics at multiple points in the fire source area. Based on the experimental data, a simulation model for the mixed combustion of multiple cable materials was established and revised, and the heat release rate (HRR) under different fire scenarios was calculated. Then, an equivalent fire source device capable of simulating the aforementioned HRR curve was designed. The results indicate that under ignition conditions with an igniter power of 400 kW and duration of 90 s, the cable fire development exhibits nonlinear dynamic evolution, with a flame height of 0.63 m. The peak temperature rise rate and peak temperature at the measurement point reach 3.27 °C/s and 926 °C, respectively. When 39.4% of the insulation layer material of the cable participates in combustion, and the fuel molecular formula is C_2.28H_5.70O_1.42N_0.08Si_0.65, the relative error between simulated and experimental temperatures during stable combustion is 3.0%. Heat release rates for mild, moderate, and severe fires stabilize near 350 kW, 420 kW, and 530 kW under this calibrated cable model. The relative error between the temperature curve from the fire source device during the stable combustion stage and that from the actual combustion experiment is 3.4%, indicating favorable equivalence. Full article

Patent foramen ovale (PFO) is a condition present in 20–25% of the general population and can rarely be associated with clinical conditions such as stroke, decompression sickness, desaturation, and migraine with aura. Screening for PFO for primary prevention is not recommended. Several trials have been published demonstrating the efficacy of percutaneous PFO closure in patients under 60 years of age with embolic stroke of unknown etiology. Such evidence has not been achieved in other patient groups, such as those with migraine with aura or decompression sickness. There is also a subset of patients, such as pregnant women or patients undergoing laparoscopic non-cardiac surgery, in whom an increased risk of paradoxical embolism requires preoperative stratification. In all cases, it is necessary to characterize the PFO based on the size of the shunt and the anatomy (e.g., the presence of a large tunnel, prominent Eustachian valve, atrial septal aneurysm), all factors that can increase the risk of paradoxical embolism. This review summarizes the current view on diagnostic and therapeutic work-up of PFO in light of the most recent international guidelines. Full article

Transparent soil technology (TST) provides a non-intrusive visualization approach for geotechnical model experiments by matching the refractive indices of transparent particles and pore fluids. This review systematically examines recent advances in TST, from material preparation to measurement methods and engineering applications. The preparation of transparent sand and transparent clay, pore-fluid matching, degassing treatment, and mechanical similarity with natural soils are summarized. The development of optical measurement and image analysis methods, including laser slicing, particle image velocimetry, digital image correlation, speckle imaging, and three-dimensional reconstruction, is then discussed to clarify the transition of TST from qualitative observation to quantitative full-field deformation measurement. Bibliometric keyword evolution further indicates that research has shifted from early material feasibility toward engineering-oriented applications and intelligent visualization. Current applications in pile–soil interaction, tunneling, slope instability, seepage, and erosion demonstrate the value of TST for revealing displacement-field evolution, strain localization, seepage-path development, particle migration, and shear-band propagation. Remaining challenges include limited mechanical similarity, optical stability, large-scale applicability, and efficient data processing. Future work should emphasize standardized material systems, high-resolution three-dimensional visualization, multiphysics coupling, and integration with artificial intelligence. Full article

Water-bearing faults pose critical hazards in tunnel excavation due to sudden water inrush, making reliable advance detection essential. This study presents a systematic forward modeling framework that integrates COMSOL Multiphysics and MATLAB to simulate three-dimensional direct current (DC) responses ahead of the tunnel face. A three-dimensional finite-element model was developed to investigate the influence of electrical anisotropy on apparent resistivity under controlled geological conditions. Electrical anisotropy of both surrounding rock and water-bearing faults is incorporated to evaluate its influence on apparent resistivity. Numerical experiments investigate the effects of surrounding-rock and fault anisotropy and reveal the mechanism behind hourglass-shaped low-resistivity anomalies. The results also reveal systematic biases when anisotropy is neglected, including forward-shifted anomaly positions, overestimated lateral extents, and more diffuse anomaly boundaries. When anisotropy is considered in both the surrounding rock and the fault, the simulated anomaly closely matches the preset fault location, demonstrating improved localization accuracy. The modeling results clarify the effects of key parameters on apparent resistivity responses and improve the interpretation of low-resistivity anomalies. They also provide a theoretical basis for enhancing the reliability of DC resistivity-based tunnel advance detection. Full article

To address the challenge of reconstructing statistical wind pressure fields of membrane structures under sparse measurement conditions, this study proposes an FF-Res-GP-PINN framework based on wind tunnel test data from a ridge–valley membrane structure. The proposed framework integrates Gaussian Fourier feature mapping, a residual network, spatial gradient penalty, and Laplacian smoothing regularization. The model takes the spatial coordinates and incoming wind direction as inputs and outputs the mean and fluctuating wind pressure coefficients. A total of 675 samples under three wind directions, namely 0°, 45°, and 90°, were used for training and validation. The results show that compared with the conventional PINN, the proposed FF-Res-GP-PINN reduces the validation MSE from 0.226 to 0.155, corresponding to a reduction of 31.4%. The ablation study indicates that Gaussian Fourier feature mapping contributes most significantly to the improvement of pointwise prediction accuracy, whereas the spatial gradient penalty and Laplacian smoothing regularization mainly enhance the spatial continuity of the predicted wind pressure field. Compared with the Fourier-MLP model, the FF-Res-GP-PINN reduces the average gradient norm, Laplacian smoothing residual, and spatial oscillation index by approximately 98.5%, 96.3% and 62.2%, respectively. The sensitivity analysis of regularization weights further demonstrates that increasing λ_grad and λ_lap can enhance spatial smoothness, but may also increase the pointwise prediction error. Therefore, λ_grad = 2 × 10⁻³ and λ_lap = 1 × 10⁻⁴ were adopted in this study as a compromise between prediction accuracy and spatial regularization for the current dataset. The findings indicate that the proposed framework provides a feasible approach for reconstructing statistical wind pressure fields of membrane structures with a specific geometry and tested wind directions. Nevertheless, its predictive capability for unseen wind directions, different structural geometries, and transient wind pressure fields requires further validation. Full article

The disengagement of contact wires in rigid overhead contact systems (ROCS) is a critical hazard to urban rail transit, potentially causing pantograph–catenary collisions, wire breakage, and large-scale catenary failures. To investigate its mechanical mechanism and detection approach, a three-dimensional solid and flexible multibody coupled model of a rigid pantograph–catenary system was established using finite element analysis and multibody dynamics simulation. The effects of train speed, contact force fluctuation, contact wire stress concentration, and disengagement degree on pantograph–catenary dynamic behavior were analyzed. The results show that the standard deviation of contact force at overlapping spans is significantly higher than that in other sections, indicating that overlapping spans are high-risk regions for disengagement. The peak stress of the contact wire is mainly concentrated at registration points and increases with train speed, which may promote abnormal wear and local deformation of the conductor rail jaw. Field-observed environmental degradation factors, such as tunnel water leakage, corrosion, and conductive grease deterioration, may further weaken the clamping performance of the conductor rail. Hazard simulations show that disengagement at overlapping spans deteriorates current collection quality and aggravates carbon strip wear, especially at the beginning of the subsequent overlapping span. Based on onboard inspection equipment, an engineering detection route integrating area-scan imaging, three-dimensional profile scanning, and line-scan imaging is proposed to support the inspection of severe and minor disengagement defects. Full article

Coupled shear wall systems are widely used in tall buildings due to their high lateral stiffness and effectiveness in controlling wind-induced serviceability responses. Reliable assessment of their behavior under realistic wind loading requires accurate load representation and properly calibrated numerical modeling. This study investigates the performance of coupled shear wall systems under wind loads derived from wind tunnel testing, where surface pressure time histories were extracted from the TPU Aerodynamic Database and used to generate equivalent full-scale, time-varying wind loads. The preliminary design of a 20-story building was established in ETABS based on current design codes. Detailed nonlinear time-history analyses were subsequently performed in OpenSees to assess the performance under three different wind hazards for the original and refined design, where shear walls were modeled using the Multiple-Vertical-Line-Element Model (MVLEM). Several wind demand indicators, including drift ratios, floor accelerations, and component and cladding performance were evaluated. The results demonstrate that the performance-based design framework enables the identification of critical vulnerabilities that may not be fully captured by conventional code-based drift and strength checks, particularly regarding localized damage accumulation and serviceability-related demands. Additionally, the refined configuration, while requiring only a 4.33% increase in total baseline concrete volume, effectively reduced peak roof drift by 60%, allowing reliable control of dynamic behavior and prevention of structural yielding, as well as ensuring the maintenance of both structural integrity and operational serviceability for the investigated high-rise configuration during severe wind events. Nevertheless, the findings are limited to the investigated building configuration and aerodynamic conditions considered in this study. Full article

Carbon nanotube (CNT) networks are promising candidate channel materials for thin-film transistors (TFTs). However, the charge trapping characteristics underlying the gate hysteresis effect still remain unclear. Herein, high-performance CNT TFTs with good consistencies were fabricated to investigate the hysteresis-induced performance variations and the dynamic charge trapping/releasing behaviors at different gate biases. Both the subthreshold and suprathreshold characteristics of the TFTs are remarkably changed under different gate sweeping directions. The origin of gate hysteresis was illustrated by comparing the effects of gas desorption and selective re-adsorption, and the adsorbed O₂ and H₂O make different contributions related to specific charge trapping characteristics. We further demonstrate that the dynamic charge trapping/releasing processes are governed by the applied gate biases, revealing the equivalency between the positive charge trapping and negative charge releasing processes, and vice versa. The time-dependent degradation of the on-state current has been fitted to perform a statistical analysis based on the measurement results of eight devices. Three characteristic time constants have been determined, corresponding to a multi-step trapping process that may be dominated by dielectric surface trapping and trap-assisted tunneling into the bulk defects in the dielectric layer near the CNTs and those in depth, respectively. Full article