Search Results (78)

Spilled hydrocarbons released from oil pipeline accidents can result in long-term environmental contamination and significant damage to habitats. In this regard, evaluating actions in response to vulnerability scenarios is fundamental to emergency management and groundwater integrity. To this end, understanding the trajectories and their influence on the various parameters and characteristics of the contaminant’s fate through accurate numerical simulations can aid in developing a rapid remediation strategy. This paper develops a numerical model using the CactusHydro code, which is based on a high-resolution shock-capturing (HRSC) conservative method that accurately follows sharp discontinuities and temporal dynamics for a three-phase fluid flow. We analyze nine different emergency scenarios that represent the breaking of a diesel oil onshore pipeline in a porous medium. These scenarios encompass conditions such as dry season rupture, rainfall-induced saturation, and varying pipeline failure pressures. The influence of the spilled oil pressure and water saturation in the unsaturated zone is analyzed by following the saturation contour profiles of the three-phase fluid flow. We follow with the high-accuracy formation of shock fronts of the advective part of the migration. Additionally, the mass distribution of the expelled contaminant along the porous medium during the emergency is analyzed and quantified for the various scenarios. The results obtained indicate that the aquifer contamination strongly depends on the pressure outflow in the vertical flow. For a fixed pressure value, as water saturation increases, the mass of contaminant decreases, while the contamination speed increases, allowing the contaminant to reach extended areas. This study suggests that, even for LNAPLs, the distribution of leaked oil depends strongly on the spill pressure. If the pressure reaches 20 atm at the time of pipeline failure, then contamination may extend as deep as two meters below the water table. Additionally, different seasonal conditions can influence the spread of contaminants. This insight could directly inform guidelines and remediation measures for spill accidents. The CactusHydro code is a valuable tool for such applications. Full article

Modeling and simulation of aneurysm formation, growth, and rupture plays an essential role in a wide spectrum of application scenarios, ranging from risk stratification to stability prediction, and from clinical decision-making to treatment innovation. Unfortunately, it remains a non-trivial task due to the difficulties imposed by the complex and under-researched pathophysiological mechanisms behind the different development stages of various aneurysms. In this paper, we present a novel computational method for aneurysm simulation using smoothed particle hydrodynamics (SPH). Firstly, we consider blood in a vessel as a kind of incompressible fluid and model its flow dynamics using the SPH method; and then, to simulate aneurysm growth and rupture, the relationship between the aneurysm development and the properties of fluid particles is established by solving the motion control equation. In view of the prevalence of aneurysms in bifurcation vessels, we further enhance the capability of the model by introducing a solution for bifurcation aneurysms simulation according to Murray’s law. In addition, a CUDA parallel computing scheme is also designed to speed up the simulation process. To evaluate the performance of the proposed method, we conduct extensive experiments with different physical parameters associated with morphological characteristics of an aneurysm. The experimental results demonstrate the effectiveness and efficiency of proposed method in modeling and simulating aneurysm formation, growth, and rupture. Full article

This paper presents a review of explosion mitigation techniques for road tunnels, with a focus on scenarios involving high-pressure hydrogen tank rupture under fire conditions. Both passive and active strategies are considered—including structural configurations (e.g., tunnel branching, vent openings, right-angle bends) and protective systems (e.g., drop-down perforated plates, high-performance fibre-reinforced cementitious composite (HPFRCC) panels)—to reduce blast impact on tunnel occupants and structures. The review highlights that while measures such as blast walls or energy-absorbing barriers can significantly attenuate blast pressures, an integrated approach addressing both blast load reduction and structural resilience is essential. This paper outlines how coupled computational fluid dynamics–finite element method (CFD–FEM) simulations can evaluate these mitigation methods, and we discuss design considerations (e.g., optimising barrier placement and tunnel geometry) for enhanced safety. The findings provide guidance for designing safer hydrogen vehicle tunnels, and they identify gaps for future research, including the need for experimental validation of combined CFD–FEM models in hydrogen fire–explosion scenarios. Full article

The water hammer phenomenon represents a significant challenge to the safe and efficient operation of pressurised water systems. This study investigates the application of hydro-pneumatic tanks (HPTs) as protective devices against transient flow events, with a particular focus on their integration into simplified modelling frameworks. Rigid and elastic water column models are examined, and their performance is evaluated through a representative case study. A multi-criteria decision matrix was employed to select a suitable simulation tool, leading to the adoption of the ALLIEVI software for implementing both modelling approaches. Comparative results indicate that the rigid water column model offers a favourable compromise between accuracy and computational efficiency under appropriate conditions. This supports its practical application in installing HPTs in design and operational scenarios. To further assess the predictive capacity of each model, a confusion matrix analysis was conducted across 57 scenarios. This approach proved effective in evaluating the models’ ability to anticipate pipeline rupture based on the initial configuration of the hydraulic installation. The elastic model achieved accuracy levels ranging from 90.7% to 100%, whereas the rigid water column model exhibited a slightly broader accuracy range, from 76.7% to 97.7%. These findings suggest that integrating machine learning techniques could enhance the rapid assessment of failure risks in water utility networks. Such tools may enable operators to determine in advance whether a given operating condition will likely lead to system failure, thus improving resilience and decision-making in managing pressurised pipeline systems. Full article

Purpose: Pickleball, the fastest-growing sport in the United States, has seen a rapid increase in participation across all age groups, particularly among older adults. However, the sport introduces specific risks for ocular injuries due to the unique dynamics of gameplay and the physical properties of the pickleball. This study aims to explore the mechanisms of pickleball-related eye injuries, utilizing finite element modeling (FEM) to simulate ocular trauma and better understand injury mechanisms. Methods: A multi-modal approach was employed to investigate pickleball-related ocular injuries. Finite element modeling (FEM) was used to simulate blunt trauma to the eye caused by a pickleball. The FEM incorporated detailed anatomical models of the periorbital structures, cornea, sclera, and vitreous body, using hyperelastic material properties derived from experimental data. The simulations evaluated various impact scenarios, including changes in ball velocity, angle of impact, and material stiffness, to determine the stress distribution, peak strain, and deformation in ocular structures. The FEM outputs were correlated with clinical findings to validate the injury mechanisms. Results: The FE analysis revealed that the rigid, hard-plastic construction of a pickleball results in concentrated stress and strain transfer to ocular structures upon impact. At velocities exceeding 30 mph, simulations showed significant corneal deformation, with peak stresses localized at the limbus and anterior sclera. Moreover, our results show a significant stress applied to lens zonules (as high as 0.35 MPa), leading to potential lens dislocation. Posterior segment deformation was also observed, with high strain levels in the retina and vitreous, consistent with clinical observations of retinal tears and vitreous hemorrhage. Validation against reported injuries confirmed the model’s accuracy in predicting both mild injuries (e.g., corneal abrasions) and severe outcomes (e.g., hyphema, globe rupture). Conclusions: Finite element analysis provides critical insights into the biomechanical mechanisms underlying pickleball-related ocular injuries. The findings underscore the need for preventive measures, particularly among older adults, who exhibit age-related vulnerabilities. Education on the importance of wearing protective eyewear and optimizing game rules to minimize high-risk scenarios, such as close-range volleys, is essential. Further refinement of the FEM, including parametric studies and integration of protective eyewear, can guide the development of safety standards and reduce the socio-economic burden of these injuries. Full article

Background: Vascular Ehlers–Danlos syndrome (vEDS) is a rare connective tissue disorder characterized by collagen type III deficiency, predisposing to spontaneous arterial, uterine, and intestinal ruptures. While intestinal complications are recognized in vEDS, intestinal failure (IF) secondary to these complications is a rare and potentially life-threatening occurrence. This study aimed to describe the clinical presentation, surgical management, and outcomes of pediatric patients with IF secondary to vEDS and to provide a comprehensive review of the limited existing literature on this challenging clinical scenario. Methods: This study comprises a case series of pediatric patients with IF due to vEDS complications and a comprehensive literature review. Clinical data were collected from medical records, including age at diagnosis, surgical history, complications, nutritional status, and long-term outcomes. A literature review was performed to identify studies reporting gastrointestinal complications, surgical outcomes in pediatric vEDS patients, and cases of intestinal failure. Results: Two pediatric patients with vEDS and IF were included. Both patients experienced intestinal perforations and surgical complications and required long-term parenteral nutrition (PN). One patient required PN for 18 months before achieving enteral autonomy, while the other remains dependent. The literature review included four articles and revealed a high risk of complications, including anastomotic leaks, fistulae, and recurrent perforations, in patients with vEDS undergoing intestinal surgery. Delayed diagnosis of vEDS was common. Conclusions: Intestinal complications in pediatric patients with vEDS can lead to severe short bowel syndrome and long-term PN dependence. Early diagnosis and a multidisciplinary approach are crucial for optimizing patient care and minimizing complications. Full article

The effects of a synthetic M 7.1 strike lateral earthquake are evaluated at five sites in Michoacan state, western Mexico. In this work, the ground motion simulation was applied using the empirical Green’s function method proposed by Irikura (1986) by scaling the recordings of an M 5.1 left-lateral event to a hypothetical M 7.1 event assuming the same source mechanism. An M 4.3 was used as a Green’s function to generate an M 5.1 synthetic earthquake. Comparing the observed and synthetic M 5.1 earthquake, parameters were adjusted in order to scale the M 7.1 earthquake. Seven scenarios were tested for which the corresponding PGA and PGV were calculated. The results show that the maximum intensities at each station depend on the proposed rupture starting point. The highest Peak Ground Acceleration was 74.1 cm/s² corresponding to an intensity MMI of V at FMIR station located 60 km from the epicenter. The synthetic results constitute a useful input for seismic hazard studies in a state with poor instrumental deployment, such as Michoacan, and for technical standards for earthquake design that could be considered in the corresponding construction regulations. Full article

The enhanced use of wood residues from the timber industry contributes to mitigating the global climate crisis. Currently, bark, a by-product of the timber industry, is primarily burned for thermal energy generation. However, with the growing demand for lignocellulosic products and the emphasis on extending life cycles, it would be more beneficial to prioritize substantial uses of bark over thermal utilization. Although numerous methods for substantial bark utilization have been explored, a significant untapped potential remains. The extractives obtained through water extraction, for instance, can be applied to various further uses like biopolymers or medical applications. This study investigates the impact of hot water extraction on the mechanical and physical properties of bark-based panels, with the aim of extending the life cycle of tree bark and its valorization in bio-based composites. The findings demonstrate that hot water extraction can enhance the bending properties (modulus of rupture, modulus of elasticity) of bark-based panels. Additionally, the extractives obtained from the process have potential applications in the pharmaceutical and adhesive industries. The study also includes an LCIA that highlights the differences between the three scenarios addressed in this research, namely energy generation from bark-based biomass, extraction of bark, and use of extracted bark residues in the production of bark-based particleboard. Full article

Background: Mycotic aneurysms of the subclavian artery are infrequent and pose significant diagnostic challenges, particularly in the context of recurrent methicillin-resistant Staphylococcus aureus (MRSA) bacteremia. The concomitant presence of upper extremity deep vein thrombosis (UEDVT) further complicates the management of bleeding risk and the necessity for anticoagulation therapy. Methods: This report discusses a 75-year-old male patient with a medical history of lung and skin cancer undergoing immunotherapy who presented with a swollen and painful right arm. Ultrasound examination identified deep vein thrombosis in the right axillary and basilic veins, and blood cultures confirmed MRSA infection. Subsequent imaging revealed bilateral subclavian artery aneurysms with contained ruptures involving previously placed stent grafts. Emergent endovascular interventions were performed to prevent catastrophic hemorrhage. Results: Despite the initial interventions, concerns regarding infected stent grafts persisted due to ongoing MRSA bacteremia and the presence of an endoleak. The complexity of balancing anticoagulation for DVT with the risk of aneurysm rupture necessitated the patient’s transfer to a tertiary care center for potential open surgical debridement. Conclusions: This case underscores the diagnostic and therapeutic challenges associated with the simultaneous occurrence of vascular infection, thrombosis, and aneurysmal pathology. Although emergency endovascular repair provided temporary hemostatic control, definitive management may require graft removal if stent infection is confirmed. Optimal care in such complex clinical scenarios demands a multidisciplinary approach and may necessitate advanced surgical interventions. Full article

Background: Completely thrombosed AAA (th-AAA) has been infrequently described in the literature. The present study evaluated the incidence and report the outcomes of open surgical repair (OSR) of a clinical series of th-AAAs. Methods: This is a single-center, observational cohort study of consecutive th-AAAs identified between 10 October 1998, and 31 January 2024. Open repair was carried out through a transperitoneal route, and Dacron knitted graft replacement. Follow-up included the clinical visit and duplex ultrasound at 30 days, and annually thereafter. The primary outcome was overall survival. The secondary outcome was the freedom from aorta-related reintervention. Results: Out of 2237 AAA repairs, we identified 16 (0.7%) th-AAAs. They were all men with a mean age of 74 years ± 8 (range, 54–89). The median of aneurysm diameter was 49 mm (IQR, 46–52). Rupture was the presenting scenario in four (25%) patients. Early mortality and major amputation did not occur. At a mean follow-up of 70 months ± 48 (range, 11–192), the freedom from aorta-related mortality was 100%, and graft-related complications were not observed. Conclusions: The incidence of th-AAA was <1%. Although rupture was the presenting scenario in nearly 25% of the cases, OSR was safe and effective due to the absence of aorta-related mortality and the long-term durability of the repair. Full article

A hydropower station, which has been in operation for over 50 years, has a penstock located in the plant’s open pipe section. Recently, concerns have been raised regarding the potential risks to the penstock’s safe operation due to wall thinning caused by abrasion. A series of stress tests, strength mathematical model analysis, and sediment erosion tests were performed on the penstock during turbine load rejection events. A stress and strain monitoring system for the steel pressure pipe was developed, enabling real-time monitoring and providing a warning function. The current wall thickness of the steel pressure pipe is about 28 mm. The results indicate that a pipe rupture is unlikely under any load rejection scenario. However, if the wall thickness is reduced to around 24 mm, the maximum equivalent stress of the pipe will approach the safety limit during load rejection. The sediment erosion test showed an erosion rate of 3.509 × 10^–5 mm/h at an average sediment concentration of 0.63 kg/m³. Assuming no other factors, such as an increase in river sediment concentration, and based on the design specifications of the steel pressure pipe and the annual average sediment concentration of 0.63 kg/m³, it is projected that the open pipe section can be operated for about 19 years before the wall thickness reaches 24 mm. It is recommended that once the wall thickness reaches 24 mm due to erosion or other factors, the pipeline system undergoes maintenance or replacement. The findings provide significant guidance for the operation of similar power stations. Full article

Background/Objectives: Kissing aneurysms, a rare and intriguing cerebrovascular anomaly, challenge even the most advanced neurosurgical techniques. These lesions, characterized by two intimately apposed aneurysms with shared arterial walls, often masquerade as single, irregular aneurysms. This report documents a case of ruptured kissing aneurysms in the M1 segment of the right middle cerebral artery (MCA), complicated by ischemic stroke and pulmonary thromboembolism (PTE)—a convergence of severe complications rarely encountered. The case underscores the importance of precise diagnostics, innovative surgical strategies, and multidisciplinary care. Methods: A 55-year-old female presented with subarachnoid hemorrhage, confirmed by advanced imaging to arise from ruptured kissing aneurysms in the M1 segment of the right MCA. Surgical intervention via a right frontotemporal craniotomy and microsurgical clipping achieved definitive aneurysmal exclusion. Postoperatively, the patient experienced ischemic stroke and PTE, necessitating dynamic adjustments in anticoagulation therapy, intensive care, and rehabilitation protocols. Results: The dual aneurysms were successfully clipped, as confirmed by intraoperative and postoperative imaging. Despite developing significant complications, including left-sided motor deficits and PTE, a carefully orchestrated treatment strategy enabled the patient’s full recovery, with marked neurological and systemic improvement by her three-month follow-up. This favorable outcome highlights the resilience of a multidisciplinary approach in navigating such high-risk scenarios. Conclusions: This case showcases the formidable challenges of managing kissing aneurysms, particularly when compounded by stroke and PTE. It emphasizes the transformative role of cutting-edge imaging and surgical techniques in achieving successful outcomes. By illustrating how precision medicine and collaborative care can overcome rare and complex cases, this report contributes valuable insights to the evolving field of cerebrovascular surgery and postoperative management. Full article

Background and Clinical Significance: Granulomatosis with polyangiitis (GPA) represents a rare autoimmune disease with granulomatous inflammation, tissue necrosis, and systemic vasculitis of the small and medium blood vessels. Although the clinical elements vary, aortic involvement is exceptional and it represents a challenge that requires a rapid intervention with the potential of displaying a fulminant evolution. Case Presentation: We report a 64-year-old male with an 18-year history of GPA who presented atypical low back pain. Following ultrasound and computed tomography exams, the initial suspicion was an intramural descending aorta hematoma, surrounded by a peri-aortic sleeve suggesting a chronic inflammation. Serial non-invasive assessments revealed a progressive lesion within the next 10 to 12 days to an aortic wall rupture, despite the absence of previous aneurysmal changes. The peri-aortic fibrous inflammatory sleeve was life-saving, and emergency minimally invasive surgery was successful, including the massive improvement in back pain. Conclusions: To our knowledge, this is a very rare scenario in GPA; we found only 18 other cases (the oldest report being from 1994). An interventional approach was mentioned in a few cases as seen in this instance. Glucocorticoid medication for GPA might act as a potential contributor to symptomatic osteoporotic fractures which require a prompt differential diagnosis. Unusual aortic manifestations (such as intramural aortic hematoma or aortic wall rupture) are difficult to recognize since the index of clinical suspicion is rather low. A prompt intervention may be life-saving and a multidisciplinary team is mandatory. Minimally invasive surgical correction of the aortic event represents an optimum management in the modern era. Such cases add to the limited data we have so far with respect to unusual outcomes in long-standing GPAs. Full article

This study is focused on developing a machine learning (ML) meta-model to predict the progression of a multiple steam generator tube rupture (MSGTR) accident in the APR1400 reactor. The accident was simulated using the thermal–hydraulic code RELAP5/SCDAPSIM/MOD3.4. The model incorporates a mitigation strategy executed through operator interventions. Following this, uncertainty quantification employing the Best Estimate Plus Uncertainty (BEPU) methodology was undertaken by coupling RELAP5/SCDAPSIM/MOD3.4 with the statistical software, DAKOTA 6.14.0. The analysis concentrated on critical safety parameters, including Reactor Coolant System (RCS) pressure and temperature, as well as reactor vessel upper head (RVUH) void fraction. These simulations generated a comprehensive dataset, which served as the foundation for training three ML architectures: Gated Recurrent Unit (GRU), Long Short-Term Memory (LSTM), and Convolutional LSTM (CNN+LSTM). Among these models, the CNN+LSTM hybrid configuration demonstrated superior performance, excelling in both predictive accuracy and computational efficiency. To bolster the model’s transparency and interpretability, Integrated Gradients (IGs)—an advanced Explainable AI (XAI) technique—was applied, elucidating the contribution of input features to the model’s predictions and enhancing its trustworthiness. Full article

This study investigates the use of cotton ropes (CRs) as a sustainable and cost-effective substitute for synthetic fiber-reinforced polymers for concrete confinement, offering significant environmental benefits such as lower CO₂ emissions and reduced energy consumption. The work evaluates the effectiveness of CR strips for confining concrete, including scenarios with recycled concrete aggregates (ReCA). Compressive strength improvements varied among specimens, with Specimen I-3F showing a 140.52% increase and Specimen II-3F achieving a 46.67% improvement. Strip configurations for Type I recycled aggregate concrete (RAC) outperformed full wraps on Type II RAC, exemplified by Specimen I-3S’s 84.51% improvement. Ultimate strain enhancements ranged from 915% to 4490.91%, driven by the significant rupture strain of cotton rope confinement. For Type I RAC, complete wrapping significantly outperformed strip configurations by 56%, 50%, and 32% in ultimate strength improvement for 1, 2, and 3 layers, respectively. The confinement ratio, varying from 0.10 to 0.70, greatly influenced the compressive behavior, with compressive strength normalized by unconfined strength increasing consistently with the confinement ratio. A minimum confinement ratio of roughly 0.40 is required to achieve an increasing second part in the compressive behavior. The initial parabolic branch was modeled using Popovics’ formulation, revealing an elastic modulus approximately 20% lower than ACI 318-19 predictions. The second branch was described using a linear approximation, and nonlinear regression analysis produced expressions for key points on the idealized compressive curve, enhancing model accuracy for CR-confined RAC. The $R^2$ values for the nonlinear regression analysis performed on experimental results were greater than 0.90. This study highlights the effectiveness of neural network expressions to predict the compressive strength of CR-confined concrete. A strength reduction (ratio of full wrap and strip wrap height CRs) factor of 0.67 was proposed and used for strip-wrapped specimens. It was seen that the neural network models also predicted the compressive strength of partially wrapped specimens with reasonable accuracy using the strength reduction factor. Full article