Search Results (3,751)

The Milano Cortina 2026 Winter Olympic Games represent a significant departure from traditional mega-event models due to their markedly polycentric territorial structure. This study investigates the sustainability of this “decentralized” model by analyzing the environmental impact of mobility flows across a vast geographic area. Adopting a methodological approach, the research integrates historical attendance data from previous Winter Games with official projections and travel time simulations to model the event’s carbon footprint. Specifically, the framework quantifies gas emissions by categorizing mobility flows into external international travel and internal inter-cluster transit. The analysis highlights a significant discrepancy between the stated sustainability objectives and the actual implementation of the infrastructural plan. Findings reveal that the total carbon debt is heavily driven by international travel, yet the localized impact on Alpine clusters remains critical due to a persistent reliance on road infrastructure over rail systems. The results suggest a “paradox of decentralized sustainability”, where the benefits of reusing existing sporting venues are offset by the environmental costs of connecting geographically fragmented sites. We conclude that without a robust and efficient public transport network, territorial dispersion acts as a catalyst for widespread anthropogenic pressure on fragile mountain ecosystems, challenging the long-term ecological legacy of the event. By empirically exposing these dynamics, this study offers a novel evaluative framework for assessing the true sustainability of distributed governance in future mega-events. Full article

During train operation, railway traction-returning current generates a power-frequency magnetic field around the rail, offering a potential energy source for self-powered trackside monitoring nodes. The H-shaped-core magnetic field energy harvester (MFEH) is attractive because it can be installed beneath the rail without enclosing the conductor, yet its output is strongly affected by the coupled rail-core-coil system. To clarify these effects, a three-dimensional electromagnetic-circuit-coupled finite-element model of an experimentally validated laminated-silicon-steel H-shaped-core MFEH was established to examine core and coil parameters. Increasing the center-leg and side-leg lengths weakens demagnetization but intensifies eddy-current losses, causing output power to approach saturation. Under a 50 Hz, 300 A current in a 54E1 rail and series-tuned matching, output power approaches 5.1 W beyond a center-leg length of 1000 mm and 3.25 W beyond a side-leg length of 700 mm. Within the investigated ranges, center-leg and side-leg lengths of approximately 800 and 400 mm provide the best power–volume performance, respectively. Increasing side-leg height or width also improves output. A larger coil span improves output by reducing internal resistance, whereas more turns yield diminishing gains because of higher winding and eddy-current losses. These findings provide a quantitative basis for parametric design of H-shaped-core MFEHs in railway environments. Full article

There is a typical coopetition relationship between the urban rail transit (URT) network scale and the urban development (UD) level. A reasonable URT network scale is essential for promoting sustainable UD. Currently, the determination of the URT network scale for planning primarily relies on qualitative approaches such as static estimation and analogical methods, which fail to dynamically reflect the coopetition relationship between URT and UD. An improved time-varying parameter Lotka–Volterra (LV) model derived from ecological theory is employed to describe the coopetition relationship between the URT network scale and the UD level. The sliding-window least squares method is applied to estimate parameters of the model. Based on the improved LV model, the lower bound of the URT network scale is obtained by solving for the minimum network scale required to promote sustainable UD under a cooperative relationship; the upper bound of the URT network scale is obtained by solving for the maximum network scale that urban resources can support under competitive conditions. The proposed model is validated using eight Chinese cities with different UD levels. The study offers quantitative theoretical insights for determining the reasonable URT network scale for planning. Full article

This study proposes a multi-criteria decision-making (MCDM) framework for the prioritization of railway switch maintenance in urban rail systems. Railway switches are critical infrastructure components subject to complex operational and structural conditions, making maintenance planning a challenging task. To address this problem, the proposed approach integrates the Analytic Hierarchy Process (AHP) for criteria weighting with TOPSIS and PROMETHEE methods for ranking alternatives. The methodology is applied to real-world data obtained from the urban rail system of Istanbul, Türkiye, including maintenance and failure records of railway switches over the period 2018–2023. Failure frequency is used as a performance indicator to evaluate the consistency of model-based rankings. The results indicate a high level of consistency between model-based and failure-based rankings, with most switches exhibiting only minor ranking deviations across methods. The proposed framework successfully identifies high-priority switches that correspond to those with the highest observed failure frequencies. Observed discrepancies are limited and can be attributed to external operational factors and data limitations. The findings demonstrate that the proposed framework provides a structured and data-informed approach for maintenance prioritization. By integrating multiple criteria with real operational data, the approach offers a practical alternative to conventional time-based maintenance strategies and supports more efficient resource allocation in urban rail systems. Full article

This work explores how graph theory and graph neural networks can support the strategic planning of rail network expansions using only publicly available city data, applied to the São Paulo Metropolitan Region. The methodology consolidates information from multiple public sources, develops a catchment-area formula to estimate potential passenger demand, applies Random Forest to identify the most relevant demographic features, and implements a GraphSAGE model that derives predictive capability from network topology together with socioeconomic features and origin–destination trips. The demand approximation was checked against observed station boardings, with predicted and observed rankings in agreement. The GraphSAGE model achieved an R² of 0.874 ± 0.042 when predicting the proxy demand indicator, with minimal overfitting, outperforming the Random Forest baseline and achieving accuracy comparable to an XGBoost baseline while overfitting substantially less; this performance remained stable under spatial cross-validation. The model is computationally efficient and requires no rail-system-specific information beyond topology, making it suitable for the fast, low-cost comparison of expansion proposals rather than as a replacement for detailed transport demand models. It was used to evaluate eleven real projects and proposals for the São Paulo Metropolitan Region. Employment, residences, and destinations where people go to eat together represent about 65% of the model’s predictive capacity. Full article

Background/Objectives: To evaluate the clinical feasibility and short-term radiographic outcomes of adapting a prosthesis-based guide system originally developed for single-implant placement for multi-implant placement in the edentulous maxilla, and to compare implant-level marginal bone change from prosthetic loading to one year between full-rough (IBT/IBNT/IBR) and hybrid-surface (MSC-IBT/MSC-IBNT) implants in a split-mouth design. Patient-reported outcomes were assessed with the OHIP-14 questionnaire. Methods: Fifteen patients with an edentulous maxilla received four or five maxillary implants placed flaplessly using a 3D-printed prosthesis-based guide incorporating polyether-ether-ketone (PEEK) rails and interchangeable angulation-correction sleeves (0°, 12°, 24°). Implants had either a fully roughened or a hybrid (rough apical and middle third with a machined coronal collar) surface. Side allocation was non-randomized: the hybrid side was assigned by alternating sequence and three patients received only full-rough implants for prosthetic reasons. All patients followed a delayed loading protocol and received a screw-retained zirconia fixed bridge. Standardized periapical radiographs were obtained at definitive prosthetic loading (baseline) and at the 12-month follow-up. Implant-level marginal bone loss was calculated as the mean of mesial and distal measurements per implant. All radiographic measurements were performed by two independent examiners (M.T. and T.M.); intra-rater reliability (M.T., remeasurement of 10 radiographs) and inter-rater reliability (M.T. versus T.M., full dataset) were quantified by intraclass correlation coefficient (ICC; two-way mixed effects, absolute-agreement, single-measurement). The primary split-mouth surface comparison was performed at the patient level by averaging implant-level change scores within each surface for each patient and comparing the paired patient-level means with a Wilcoxon signed-rank test. No a priori sample-size calculation was performed; the study was designed as a feasibility pilot. Results: Sixty-one implants were placed in 15 patients (seven male, eight female; mean age 62.5 ± 8.9 years; three current smokers). Four implants in three patients required removal and replacement during the observation period (three early failures, one late failure; per-implant early-failure rate of 3/61, 4.9%); one patient (P7) withdrew from clinical follow-up. Paired baseline and 12-month radiographs were available for 53 implants from 14 patients. Median implant-level marginal bone level increased from 0.38 mm (IQR 0.20–0.54) at baseline to 0.78 mm (IQR 0.47–1.32) at 12 months (paired Wilcoxon signed-rank, p < 0.001); two implants exceeded 4 mm of bone change at 12 months. In the patient-level paired surface comparison (n = 8 patients contributing at least one full-rough and one hybrid implant with paired data), full-rough implants showed less 12-month marginal bone change than hybrid implants in every paired patient (median paired difference full-rough hybrid of −0.49 mm; Hodges–Lehmann pseudo-median of 0.55 mm; paired Wilcoxon p = 0.012). OHIP-14 scores at one year (n = 14) showed a pronounced floor effect, with most patients scoring zero across most domains. Both intra-rater (M.T.) and inter-rater (M.T. versus T.M.) reliability showed good agreement (ICC = 0.85). Conclusions: A prosthesis-based guide system originally validated for single-implant placement can be feasibly adapted for flapless multi-implant rehabilitation of the edentulous maxilla, with early clinical and radiographic outcomes broadly consistent with comparable published series. Contrary to the design rationale that a machined coronal collar would limit early crestal remodeling, full-rough implants showed less 12-month within-patient bone change than hybrid implants in the eight paired patients; this finding is preliminary and hypothesis generating given the small, unbalanced paired sample and the contrast with larger published series. The approach is best characterized as a reduced infrastructure alternative to proprietary guided-surgery platforms, remains operator dependent, and requires confirmation in formally powered, balanced split-mouth trials with concealed allocation, placement anchored bone level measurement, postoperative CBCT for deviation quantification, and longer follow-up. Full article

This paper proposes a novel data-driven K-Gap metric method based on the Koopman operator for the detection and isolation of multiplicative faults in high-speed train suspension systems. A systematic comparison is conducted with a data-driven K-Gap approach implemented through the fuzzy modeling framework. First, Takagi–Sugeno (T–S) theory is employed to extend the K-Gap metric for nonlinear dynamic modeling of the suspension system. Subsequently, the Koopman operator framework is introduced to lift the system states into a high-dimensional observable space, enabling a globally linear representation of the system. Building upon Koopman-based stable kernel representation (SKR), a more accurate K-Gap residual metric is constructed. Finally, a unified fault diagnosis scheme is developed with the K-Gap metric as the core indicator, and the two approaches are experimentally compared in terms of their performance in detecting and isolating multiplicative faults. The experimental results demonstrate that the Koopman-based method significantly outperforms the T–S fuzzy model in terms of residual separability, fault classification accuracy, and diagnostic stability, confirming its effectiveness and superiority for fault diagnosis in complex nonlinear systems. Full article

To address the complex and highly variable wheel–rail adhesion behavior on high-speed railway curves, this study establishes a numerical wheel–rail rolling contact model based on starved elastohydrodynamic lubrication (EHL) theory and Herschel–Bulkley rheological characteristics. The model validation yielded RMSE = 0.0228, MAE = 0.0217, MAPE = 11.80%, R² = 0.828, and a 95% confidence interval of the mean residual of −0.0298 to −0.0136. The study focuses on the initial operational phase after application, systematically quantifying the fluid-dynamic regulation mechanisms of water-based friction modifiers once a thin, starved lubricating film has been formed on the rail surface under curving conditions. By analyzing rail profiles (CHN60 and CHN60N), operating parameters, and track geometry, this study shows how adhesion behavior on curved track sections is governed by the coupled effects of contact mechanics and lubrication. As the outer rail superelevation increases from 0 to 70 mm, the adhesion coefficient decreases by approximately 15–25%, mainly because the reduced normal force shifts the wheel–rail interface toward the Stribeck transition regime. Increasing axle load from 14 t to 30 t reduces the dimensionless film thickness, but the enlarged contact area contributes to a more stable adhesion level, with an increase of about 12%. Compared with the CHN60 profile, the CHN60N profile exhibits better geometric conformity, producing a lubricating film that is 10–15% thicker and leading to a lower and more stable adhesion coefficient, decreasing from approximately 0.35 to 0.1. The results also identify a critical lateral displacement of around −4 mm, beyond which the contact radius becomes stable and the adhesion coefficient reaches a minimum plateau. These findings clarify the competing effects of fluid entrainment and metallic asperity contact, and provide quantitative guidance for friction management and friction modifier application on curved track sections. Full article

Background: Strengthening, coordinating, and sustaining rail freight services is one of the most pressing yet neglected challenges for transport planners in developing economies. Focusing on the institutional context of Thai freight transport, we assess, contextualise, and rank the collaboration factors shaping rail freight competitiveness. Methods: MICMAC analysis was selected because it does not require a pre-defined hierarchical structure and it is computationally straightforward for small variable sets. A qualitative study comprising semi-structured interviews was conducted with participants from government transport agencies, the State Railway of Thailand (SRT), private logistics operators, and freight customers. Results: The analysis extracted six key factors: government policy, finance, infrastructure readiness, technology and innovation, information sharing, and human resource capacity. Government policy alone occupies the driving quadrant, exerting the strongest systemic influence. Finance and infrastructure readiness emerge as linkage factors, simultaneously shaping and being shaped by the wider network, whereas technology, information sharing, and human resources sit in the dependent quadrant and respond to change. Conclusions: This classification allows us to derive seven collaboration strategies matched with appropriate policy levers; the three highest-ranked are policy collaboration, economic instruments, and multimodal integration. Full article

In automated container terminals, Autonomous Rail-guided Transporters (ARTs) are responsible for horizontal transportation tasks between quay cranes and yard blocks during unloading operations. Their charging strategies directly affect operational continuity, charging resource utilization, and road traffic load. To improve the consistency between the simulation environment and the actual terminal layout, this study constructs a DXF-based directed traffic network based on the CAD/DXF layout of Tianjin Port Second Container Terminal. A coupled discrete-event simulation model integrating ART operations, charging behavior, and traffic dynamics is developed using SimPy. The study further compares several charging strategies, including threshold charging, conventional opportunity charging, safe opportunity charging, interval charging, and Distance-Aware Interval Charging (DAIC). The results indicate that the conventional opportunity charging strategy suffers from battery depletion failures under continuous unloading task flows due to the absence of mandatory low-battery protection. After introducing a safety threshold, the safe opportunity charging strategy effectively eliminates the risk of battery depletion. Considering comprehensive performance indicators, including operational success rate, task completion time, charging travel distance, charging frequency, minimum State of Charge (SOC), and road congestion level, the 40%/70% interval charging strategy demonstrates strong overall robustness, while the 40%/80% interval charging strategy shows advantages in completion time and charging resource utilization. Both strategies can therefore be regarded as key candidate charging schemes for ART operations in Tianjin Port Second Container Terminal. Full article

The virtually coupled train set (VCTS) system is a promising urban rail transit paradigm that replaces physical couplers with train-to-train (T2T) wireless communication, enabling dynamic marshaling to achieve the precise matching of transportation demand and resources. However, existing VCTS control strategies either assume perfect leader state availability, rely on continuous communication, or lack guaranteed transient/steady-state performance under Denial-of-Service (DoS) attacks. To address these critical limitations, this paper proposes a unified finite-time resilient event-triggered cooperative control framework for VCTSs against malicious DoS attacks. The proposed framework integrates three synergistic components: a distributed finite-time leader state estimator to reconstruct leader information under intermittent communication interruptions, a prescribed performance finite-time controller to bound tracking error fluctuations and accelerate convergence, and an adaptive event-triggered communication protocol to reduce controller update frequency. The closed-loop system stability, finite-time convergence, and prescribed performance guarantees are rigorously proven via Lyapunov analysis, and Zeno behavior is strictly excluded. Extensive comparative simulations demonstrate that the proposed framework outperforms representative state-of-the-art methods in terms of tracking accuracy, attack resilience, and communication efficiency, achieving a significance reduction of approximately 70% in controller update frequency while maintaining system stability under the considered DoS attack scenarios. Full article

Large-scale infrastructure projects routinely divide construction responsibilities across several specialized contractors whose scopes are simultaneously independent and mutually reliant, producing boundary zones where design changes, remedial obligations, and contractual disputes repeatedly emerge. This study examines how interface-related risks are distributed between civil construction contractors and core system contractors, drawing on fieldwork conducted within the Taiwan High Speed Rail (THSR) project. Questionnaire surveys were administered to 38 practitioners who held direct THSR involvement or comparable experience in analogous multi-party infrastructure projects, yielding a valid response rate of 63.3%. Using a weighted influence scoring approach, 37 risk factors grouped into seven interface categories were evaluated. Results show that Variation (top-ranked item A07, score 290/300), Care of Works (B01, 284/300), and Cooperation and Coordination (D04, 285/300) represent the three most consequential risk domains. Analysis of risk-initiation patterns indicates that project owners are the predominant source of variation-related risks, while core system contractors most frequently trigger care-of-works incidents. Structured comparison of FIDIC (1995), AIA/A201 (1997), NEC/ECC (1995), ENAA (1996), and THSR contractual documents uncovers a shared shortcoming: no examined standard form contains explicit provisions tying risk liability to the party whose conduct gave rise to the risk. Evidence from three documented THSR dispute cases is consistent with the survey data and illustrates the real-world consequences of this drafting gap. On this basis, the study proposes a risk-trigger principle as a potential framework for improving interface risk allocation in future multi-party infrastructure contracts. Full article

This study comparatively evaluated Raydent (here interpreted as a standard black chrome-type industrial condition in the present specimen context), DLC, and SiO₂ coatings for high-precision LM-guide applications as an application-oriented initial screening study. The emphasis was placed on dimensional preservation, surface integrity, and mechanical surface response rather than on complete coating-mechanism validation. Cross-sectional FE-SEM, EDS, Vickers hardness testing, surface profilometry, AFM, and SEM analyses were conducted to compare coating thickness, composite surface hardness, roughness, and morphology, and the influence of plasma pretreatment on the SiO₂ system was additionally investigated. Among the investigated coatings, SiO₂ exhibited the smallest thickness (1.03 μm), highest composite surface hardness (719.8 HV), and lowest average roughness (213.5 nm), suggesting favorable dimensional compatibility and surface integrity under the tested conditions. Plasma pretreatment increased the EDS-detected Si signal from 0.77 to 2.81 wt% and improved the composite surface hardness from 580 to 720 HV, suggesting an altered near-surface response and improvement in coating formation during pretreatment-assisted processing. AFM and SEM observations further indicated that the SiO₂ coating provided a more uniform and flatter surface morphology on the coupon specimens, whereas the DLC specimen prepared under the present commercial condition showed localized protrusions that may be associated with initial local contact disturbance. The comparative results suggest that SiO₂ coatings provide a favorable balance of thickness control, surface uniformity, composite surface hardness, and roughness for precision LM-guide applications. Although additional rolling-contact durability, adhesion, wear, friction-coefficient, and rolling-contact-fatigue studies are still required, the present findings should be interpreted as an initial screening result indicating that SiO₂ is a candidate coating condition for further engineering consideration in precision motion-guide systems, rather than as a direct validation of full tribological or long-term durability performance. Full article

(1) Introduction: Transit-oriented development is often framed as a strategy to expand opportunity and advance equitable transportation. However, evidence suggests it can also contribute to rising housing costs and displacement in historically marginalized communities. This study examines how a light rail expansion reshaped displacement risk in a Latina/o community in the U.S. Southwest, identifying early mechanisms through residents’ interpretations of the expansion during construction. (2) Materials and Methods: Using a qualitative, community-engaged design, the study draws on ten in-depth pláticas with Latina/o residents conducted during construction of a major rail expansion. Data were analyzed abductively and guided by Critical Race Ecological Systems Theory (CrEST) to identify multilevel mechanisms linking infrastructure policy to lived social conditions. (3) Results: Findings identify three mechanisms through which transit investment generated displacement risk prior to relocation. First, historical and intergenerational memory shaping anticipatory displacement. Second, place-based belonging intensifying psychosocial stress and loss. Third, policy-mediated mobility constraining residents’ ability to remain or benefit from reinvestment. (4) Discussion: Transit infrastructure operates as a structural policy intervention that reorganizes risk, belonging, and stability when histories of racialized disinvestment are not incorporated into policy design. These findings position infrastructure planning as a critical site for social work policy analysis and prevention-oriented intervention. Full article

With the increase in operation time of DC traction systems due to the environment of tunnel and stress rupture, the insulation between the rail and ground inevitably decreases, causing increased stray current leakage. In view of this, we present an analytical and electrochemical study of stray current behavior and its corrosion impact arising from local rail-to-ground insulation damage in DC urban rail systems. A two-layer rail–earth continuous model of stray current distribution is developed (unilateral and bilateral supply cases) using Kirchhoff network formulations with insulation damage boundary conditions. Numerical simulations quantify the effects of damage location and grounding resistance on rail potential shifts, abrupt changes in rail and stray currents, and total leakage. To assess electrochemical consequences for nearby buried pipelines, the electrical model is proposed in this work with an impedance-informed corrosion model and Monte Carlo sampling of operational and electrical uncertainties to estimate dynamic corrosion rates and pitting evolution. The results show that single–point insulation faults shift the rail zero potential toward the fault, leading to instantaneous jumps in leakage and rail currents whose magnitude grows as damaged-point resistance decreases, markedly increasing pipeline corrosion risk. The integrated electrical-electrochemical framework provides a tool for detection, risk assessment, and mitigation planning for stray current-induced pipeline corrosion. Full article