Search Results (929)

In recent years, the increasing frequency of intense rainfall events has led to a surge in landslide occurrences, posing severe threats to human safety and ecological integrity. This study utilizes the Universal Distinct Element Code (UDEC) for discrete element numerical simulations, combined with field observation-based mechanism analysis, to examine the primary drivers of landslide formation: rainfall and underground mining. Focusing on the Zengziyan landslide in Chongqing as a case study, the research investigates the underlying instability mechanisms. The findings indicate that mining activities primarily compromise slope stability by modifying rock structures, diminishing supporting forces, and creating goaf areas. Notably, these goaf zones generate an overhanging effect on the overlying rock mass, promoting crack initiation and the propagation of structural planes. Under rainfall conditions, groundwater infiltration and elevated pore water pressure exert a more substantial destabilizing influence, markedly accelerating rock mass sliding and collapse. The analysis reveals that rainfall predominantly governs landslide initiation and evolution, particularly during the triggering and rapid acceleration phases of slope instability. The outcomes of this research offer valuable insights for post-mining slope management and monitoring, as well as for developing landslide early warning systems in rainy conditions. Full article

Background and Clinical Significance: Upadacitinib, a selective Janus kinase 1 (JAK1) inhibitor, is increasingly prescribed for autoimmune and inflammatory diseases. Although its therapeutic safety profile is well established, fatal intoxications have not been reported to date. Case Presentation: We describe the first fatal case of upadacitinib overdose in a 13-year-old girl. Following ingestion of approximately 600 mg (40 × 15 mg tablets Rinvoq^®), the patient presented with deep coma, profound bradycardia (~40 bpm) with third-degree atrioventricular block, conduction delay, hypotension, hypothermia, and metabolic acidosis. Laboratory tests showed hyperglycemia (17.8 mmol/L) and only minimal elevations in cardiac biomarkers (CK 57.03 U/L, CK-MB 30.64 U/L, troponin 0.003 ng/mL). Despite advanced resuscitation, the patient succumbed within a few hours. Forensic toxicology revealed extremely high concentrations of upadacitinib, 1.84 µg/mL (~1840 ng/mL) in blood and 70.3 µg/mL in gastric contents, far exceeding reported therapeutic plasma levels (Cmax 36.0 ± 8.8 ng/mL). This case establishes the first reported value for a lethal upadacitinib concentration in humans. The combination of conduction abnormalities, refractory shock, and minimal biomarker changes is consistent with an acute electrophysiological and hemodynamic collapse rather than myocardial infarction. Conclusions: The toxicity of upadacitinib in this case is characterized by profound central nervous system depression, severe cardiovascular (electrophysiological and hemodynamic) disturbances, and metabolic abnormalities (acidosis and hyperglycemia). These findings provide essential reference data for clinical and forensic toxicology, highlight the fatal potential of upadacitinib in overdose, and underscore the importance of secure medication storage and pharmacovigilance in households with adolescents. Full article

Construction safety remains a critical concern, with frequent accidents leading to fatalities, severe injuries, and significant economic losses. To address these challenges and enhance accident prevention, this study adopts a systems thinking approach to investigate the causal factors of construction safety accidents. First, drawing on Rasmussen’s risk management framework, this study developed a Construction Accident Causation System (CACS) model that comprises six hierarchical levels and 23 influencing factors. Through the analysis of 331 investigation reports of construction accidents in China, causal factor correlations were refined, and the topological structure and network parameters of the model were determined. This study integrates diagnostic reasoning, sensitivity analysis, and fuzzy mathematics within a Bayesian Network (BN) framework. Through this approach, it identifies the most probable accident pathways and highlights seven critical and three sensitive factors that jointly exacerbate construction safety risks. A real-world case of a formwork collapse in Baotou City is further analyzed to verify the model’s reliability and practical relevance. The results confirm that the integrated CACS and BN framework effectively captures the multi-level interactions among managerial, behavioral, and technical factors, providing a scientific basis for proactive safety management and accident prevention in the construction industry. Full article

While urban historic areas are most vulnerable to disasters, they offer insights into leveraging their features to mitigate risk. This study analyzes scientific approaches to evacuation simulations to assess the tolerance of historic areas. Using a heritage-led disaster risk reduction approach, this study uses a heritage site as a case study for evacuation. This study uses a GIS-based methodology to define various blockage risks, categorizing them as no-obstruction, rubble-obstruction, on-street vehicle obstruction, and combined obstruction. The input parameters were transferred from a GIS to a simulation application, with combined obstruction representing the worst-case scenario. No-obstruction served as a baseline for measuring historic area vulnerability. Statistical analysis evaluated time usage and the number of evacuees, while GIS identified vulnerable places and street congestion. Obstructions significantly increase evacuation risks, with combined obstructions posing a 3.8 times higher risk than the no obstruction scenario (2638 s compared to 683 s). Vehicle obstruction causes a vulnerability of 1404 s, while building collapse-related rubble obstruction causes a vulnerability of 1073.1 s, despite creating dead-end streets. The strategy of reinventing heritage sites as temporary evacuation sites appears viable. This approach can support evacuees during and after disaster responses and expand options for ensuring urban heritage resilience. Full article

Karst ground collapses triggered by groundwater fluctuations pose a significant threat to the safety and stability of tunnel engineering. In this study, taking the Yakouzai Tunnel as a case, a combination of physical model tests and numerical simulations was employed to investigate the mechanisms of groundwater-induced karst collapse. A self-designed physical model device reproduced the full process of soil cavity initiation, expansion, and roof failure. Numerical simulations were further conducted to analyze the evolution of pore water pressure, stress distribution, and displacement under both groundwater drawdown and rise conditions. The results indicate that concentrated seepage erosion at the cavity arch foot is the primary driver of cavity initiation, with cyclic suffusion promoting its progressive expansion. Rapid groundwater drawdown generates vacuum suction that markedly reduces roof stability and may induce sudden collapse, whereas groundwater rise, although providing partial support to the roof, intensifies shear stress concentration and leaves the cavity in an unstable state. The findings highlight that karst collapse is governed by the coupled effects of seepage erosion, arching degradation, differential settlement, and vacuum suction, providing a scientific basis for monitoring, prediction, and mitigation of karst hazards. Full article

The finite element method (FEM) and discrete element method (DEM) have been widely applied to analyze the deformation and failure processes of embankment slopes. Although both methods can produce promising results, the choice between them has long remained unresolved. In this study, a failure case of a granite residual soil (GRS) embankment was analyzed. FEM and DEM models were established to simulate the instability process of this embankment slope, and the applicability of both methods to GRS embankments was then evaluated. The main conclusions are as follows: (1) Geotechnical parameters of GRS were determined through laboratory testing, and FEM and DEM models were developed to reproduce the deformation and failure behavior of the embankment slope subjected to rainfall and vehicle loading. (2) Similar rainfall infiltration patterns were obtained from both FEM and DEM simulations; however, significant differences in deformation were observed. The FEM-predicted deformation was 0.075 m after rainfall, indicating that the embankment remained stable. In contrast, the DEM-predicted deformation reached 1.4 m, indicating that the embankment slope had already become unstable. (3) The DEM simulation closely reproduced the failure of the GRS embankment slope observed in the field. It realistically captures the process of particle disintegration in GRS caused by rainfall infiltration, as well as the subsequent slope collapse. Therefore, DEM can be regarded as the most appropriate approach for modeling the instability of GRS embankment slopes. Full article

In order to reduce the risk of collapse disasters during tunnel construction in mountainous areas and to make full use of the available data, a collapse risk assessment model for highway tunnel construction was established based on the WOA–XGBOOST algorithm. Three major categories of tunnel construction risk, namely engineering geological factors, survey and design factors, and construction management factors, were selected as the first-level indicators, and 14 secondary indicators were further specified as the input variables of the collapse risk assessment model for tunnel construction. The confusion matrix and accuracy metrics were employed to evaluate the training and prediction performance of the risk assessment model on both the training set and the test set. The results show that subjective weights derived from the G1 method were integrated with objective weights generated by the WOA–XGBOOST algorithm. A game-theory-based weight integration strategy was then applied to optimize the combined weights, effectively mitigating the biases inherent in single-method weighting approaches. Risk quantification was systematically conducted using a cloud model, while spatial risk distribution patterns were visualized through graphical cloud-mapping techniques. After completion of model training, the proposed model achieved a high accuracy of over 99% on the training set and around 95% on the held-out test set based on an available dataset of 100 collapse-prone tunnel construction sections. Case-based verification further suggests that, in the studied collapse scenarios, the predicted risk levels are generally consistent with the actual engineering risks, indicating that the model is a promising tool for assisting tunnel construction risk assessment under similar conditions. The research outcomes provide an efficient and reliable approach for assessing risks in tunnel construction, thereby offering a scientific basis for engineering decision-making processes. Full article

Abductive reasoning—the search for plausible explanations—has long been central to human inquiry, from forensics to medicine and scientific discovery. Yet formal approaches in AI have largely reduced abduction to eliminative search: hypotheses are treated as mutually exclusive, evaluated against consistency constraints or probability updates, and pruned until a single “best” explanation remains. This reductionist framing fails on two critical fronts. First, it overlooks how human reasoners naturally sustain multiple explanatory lines in suspension, navigate contradictions, and generate novel syntheses. Second, when applied to complex investigations in legal or scientific domains, it forces destructive competition between hypotheses that later prove compatible or even synergistic, as demonstrated by historical cases in physics, astronomy, and geology. This paper introduces quantum abduction, a non-classical paradigm that models hypotheses in superposition, allowing them to interfere constructively or destructively, and collapses only when coherence with evidence is reached. Grounded in quantum cognition and implemented with modern NLP embeddings and generative AI, the framework supports dynamic synthesis rather than premature elimination. For immediate decisions, it models expert cognitive processes; for extended investigations, it transforms competition into “co-opetition” where competing hypotheses strengthen each other. Case studies span historical mysteries (Ludwig II of Bavaria, the “Monster of Florence”), literary demonstrations (Murder on the Orient Express), medical diagnosis, and scientific theory change. Across these domains, quantum abduction proves more faithful to the constructive and multifaceted nature of human reasoning, while offering a pathway toward expressive and transparent AI reasoning systems. Full article

Corrosion in reinforced concrete (RC) structures increases seismic fragility by reducing strength, ductility, and bond integrity, which becomes critical in aging infrastructure. This study provides a systematic fragility comparison of intact, corroded, and FRP-strengthened structures across multiple corrosion levels under sequential earthquakes. The seismic fragility of corroded RC frames, with and without fiber-reinforced polymer (FRP) retrofitting, is investigated under both mainshock and aftershock loading conditions. A total of 508 real recorded mainshock–aftershock ground motion sequences are selected as seismic inputs to ensure the representation of earthquake demands. Nonlinear time history analyses are carried out to establish fragility curves for four limit states based on probabilistic demand–capacity relationships. The results show that corrosion significantly decreases the collapse prevention capacity (LS₄), with the maximum reduction reaching about 62%. FRP retrofitting restores seismic performance to varying degrees depending on corrosion severity. For the structure with a 10% corrosion rate, FRP retrofitting enhances the collapse capacity beyond that of the intact case. For the structure with a 20% corrosion rate, FRP retrofitting recovers approximately two-thirds of the lost capacity caused by reduced ductility. The consideration of aftershock effects further increases the fragility of corroded structures, yet FRP retrofitting continues to provide improvement by reducing cumulative damage and improving deformation capacity. The study confirms that the FRP confinement effectively enhances the seismic resilience of aging RC structures and provides a practical basis for performance-based retrofit strategies under sequential earthquake events. Full article

Type B aortic dissection (TBAD) requires management tailored to the disease phase and clinical presentation, with the subacute period representing a favorable window for endovascular intervention due to improved procedural safety and remodeling potential. We report the case of a 38-year-old male with hypertension, dyslipidemia, and bicuspid aortic valve disease who presented one month after symptom onset with persistent chest pain and progressive bilateral lower-limb numbness. Clinical examination suggested early spinal cord ischemia, while laboratory tests demonstrated acute hepatic and renal dysfunction. CT angiography revealed a subacute TBAD with a markedly expanded false lumen and near-complete compression of the true lumen, resulting in visceral, renal, and potential spinal malperfusion. Given the high-risk anatomy and evolving organ dysfunction, a staged hybrid strategy was undertaken. A left carotid–subclavian bypass was performed to secure proximal landing for endovascular repair, followed the next day by thoracic endovascular aortic repair (TEVAR) using two thoracic stent grafts. Postoperative recovery was favorable, with rapid resolution of neurological symptoms and normalization of hepatic and renal parameters, allowing discharge on postoperative day seven. This case underscores the importance of early recognition of malperfusion and timely hybrid intervention in subacute TBAD with severely compressed true lumen, demonstrating excellent early clinical outcomes. Full article

This manuscript examines the rotational dynamics of rigid bodies in five-dimensional Euclidean space. This results in ten coupled nonlinear differential equations for angular velocities. Restricting rotations along certain axes reduces the 5D equations to sets of 4D Euler equations, which collapse to the classical 3D Euler equations. This demonstrates consistency with established mechanics. For bodies with equal principal moments of inertia (e.g., hyperspheres and Platonic solids), the rotation velocities remain constant over time. In cases with six equal and four distinct inertia moments, the solutions exhibit harmonic oscillations with frequencies determined by the initial conditions. Rotations are stable when the body spins around an axis with the largest or smallest principal moment of inertia, thus extending classical stability criteria into higher dimensions. This study defines a 5D angular momentum operator and derives commutation relations, thereby generalizing the familiar 3D and 4D cases. Additionally, it discusses the role of Pauli matrices in 5D and the implications for spin as an intrinsic property. While mathematically consistent, the hypothesis of a fifth spatial dimension is ultimately rejected since it contradicts experimental evidence. This work is valuable mainly as a theoretical framework for understanding spin and symmetry. This paper extends Euler’s equations to five dimensions (5D), demonstrates their reduction to four dimensions (4D) and three dimensions (3D), provides closed-form and oscillatory solutions under specific inertia conditions, analyzes stability, and explores quantum mechanical implications. Ultimately, it concludes that 5D space is not physically viable. Full article

The structural performance of mid-rise buildings with a soft first story is a critical issue in earthquake-prone regions. This paper presents a detailed assessment of both the seismic performance and the structural reliability of a confined masonry mid-rise building with a soft reinforced-concrete first-story irregularity located in Mexico. This structure was designed according to outdated building codes to reflect construction practices that remain common in some parts of the country. Nonlinear dynamic analyses were conducted using ETABS v21. To simulate various seismic scenarios, ground motion records associated with return periods of 72, 475, and 975 years, respectively, were implemented. The results demonstrated that maximum inter-story drift is predominantly concentrated at the first story, exceeding the performance thresholds for immediate occupancy, life safety, and collapse prevention. Furthermore, a probabilistic performance assessment was developed considering the randomness of inter-story drift responses. Then, reliability index (β) was calculated for each seismic scenario. In all cases, β values remained consistently below the minimum recommended limit. These findings confirm the formation of a soft-story mechanism at the first level and are relevant for buildings designed under construction provisions like those used in the present case study. Full article

Poly(N-isopropylacrylamide) (PNIPAM) hydrogels are temperature-sensitive materials whose swelling is difficult to predict near the gel collapse temperature (GCT). A physics-informed neural network (PINN) was developed in which a stabilized free-energy model is embedded and sparse data for free and uniaxially constrained swelling are assimilated. Across datasets, the PINN reduces test RMSE by 44% at low crosslink density ($N\nu =0.0035$) and by 65% at higher density ($N\nu =0.02$), with coverage inside ±RMSE bands improving from 61.9% to 76.2% for free swelling at Nν = 0.0035. Under constraint, test relative error decreases from 19.95% to 11.86% ($n=1$) and from 9.19% to 5.90% ($n=3$), while preserving thermodynamic stability. The method sharpens the transition slope near the gel-collapse temperature and narrows prediction intervals without overfitting, capturing cold-regime plateaus and hot-side tails more faithfully. The framework integrates governing equations with data to deliver accurate swelling and stress predictions using only eight anchors and thirteen held-out points per case. These results position PINNs as a reliable surrogate for designing thermo-responsive hydrogels in soft actuators and biomedical systems. Full article

The ultimate strength of the hull girder represents one of the key criteria in the design of large thin-walled steel structures such as ships and aircrafts. For large ship structures, the hull girder’s ultimate strength is expressed as the maximum internal vertical bending moment that the hull structure can absorb before collapse. In this paper, a progressive collapse analysis of the hull girder has been performed for several different variants of large steel thin-walled box girders, taken from the literature as benchmark cases, using the nonlinear finite element method (NLFEM), considering both material and geometrical nonlinearity. Results from the performed calculations were compared to the numerical results of other researchers published in the literature, as well as the results of our physical experiment. The influence of initial geometrical imperfection on the value of the ultimate bending moment achieved with NLFEM has been investigated. Full article

The increasing penetration of inverter-based renewable generation has reduced rotational inertia in power systems worldwide, causing steeper frequency drops after severe contingencies and increasing the risk of load shedding. In the Honduran context, this study evaluates the dynamic response of the National Interconnected System (NIS) operating in island mode through detailed DIgSILENT PowerFactory simulations, explicitly incorporating the national Under-Frequency Load Shedding (UFLS) scheme. Five disturbance scenarios were analyzed, including generation losses of 100 MW, 200 MW, and 262 MW, to assess the frequency support provided by Battery Energy Storage Systems (BESSs) and Flywheel Energy Storage Systems (FESSs). Results show that, in the base case, frequency decreased to 55.3 Hz during a 200 MW loss, confirming the system’s high vulnerability. The integration of a 75 MW BESS improved frequency stability to 58.74 Hz, preventing UFLS activation, while a 320 MW equivalent FESS provided only short-term inertial support with limited effectiveness. Quantitatively, the BESS reduced the minimum frequency, delayed UFLS activation by approximately 3.5 s, and provided sustained support, whereas the FESS contributed mainly during the first 5 s of the disturbance. In the most severe contingency (262 MW generation loss), the combined operation of BESS and FESS prevented total system collapse, improving the frequency nadir to 58.6 Hz. These results confirm that BESS provides more robust and sustained frequency support than FESS under the analyzed conditions, highlighting its effectiveness for improving system stability in low-inertia networks such as Honduras. The findings offer useful insights for future studies on storage integration and frequency regulation strategies. Full article