Application of a digital twin for highway tunnels based on multi-sensor and information fusion

Due to the harsh environment of highway tunnels and frequent breakdowns of various detection sensors and surveillance devices, the operational management of highway tunnels lacks effective data support. This paper analyzes the characteristics of operational surveillance data in highway tunnels. It proposes a multimodal information fusion method based on CNN–LSTM–attention and designs and develops a digital twin for highway tunnel operations. The system addresses issues such as insufficient development and coordination of the technical architecture of operation control systems, weak information service capabilities, and insufficient data application capabilities. The system also lacks intelligent decision-making and control capabilities. The developed system achieves closed-loop management of “accurate perception–risk assessment–decision warning–emergency management” for highway tunnel operations based on data-driven approaches. The engineering demonstration application underscores the system’s capacity to enhance tunnel traffic safety, diminish tunnel management costs, and elevate tunnel driving comfort

Enhanced YOLOv5s + DeepSORT method for highway vehicle speed detection and multi-sensor verification

Addressing the need for vehicle speed measurement in traffic surveillance, this study introduces an enhanced scheme combining YOLOv5s detection with Deep SORT tracking. Tailored to the characteristics of highway traffic and vehicle features, the dataset data augmentation process was initially optimized. To improve the detector’s recognition capabilities, the Swin Transformer Block module was incorporated, enhancing the model’s ability to capture local regions of interest. CIoU loss was employed as the loss function for the vehicle detection network, accelerating model convergence and achieving higher regression accuracy. The Mish activation function was utilized to reduce computational overhead and enhance convergence speed. The structure of the Deep SORT appearance feature extraction network was modified, and it was retrained on a vehicle re-identification dataset to mitigate identity switches due to obstructions. Subsequently, using known references in the image such as lane markers and contour labels, the transformation from image pixel coordinates to actual coordinates was accomplished. Finally, vehicle speed was measured by computing the average of instantaneous speeds across multiple frames. Through radar and video Multi-Sensor Verification, the experimental results show that the mean Average Precision (mAP) for target detection consistently exceeds 90%. The effective measurement distance for speed measurement is around 140 m, with the absolute speed error generally within 1–8 km/h, meeting the accuracy requirements for speed measurement. The proposed model is reliable and fully applicable to highway scenarios

Methylprednisolone as Adjunct to Endovascular Thrombectomy for Large-Vessel Occlusion Stroke

Importance It is uncertain whether intravenous methylprednisolone improves outcomes for patients with acute ischemic stroke due to large-vessel occlusion (LVO) undergoing endovascular thrombectomy. Objective To assess the efficacy and adverse events of adjunctive intravenous low-dose methylprednisolone to endovascular thrombectomy for acute ischemic stroke secondary to LVO. Design, Setting, and Participants This investigator-initiated, randomized, double-blind, placebo-controlled trial was implemented at 82 hospitals in China, enrolling 1680 patients with stroke and proximal intracranial LVO presenting within 24 hours of time last known to be well. Recruitment took place between February 9, 2022, and June 30, 2023, with a final follow-up on September 30, 2023.InterventionsEligible patients were randomly assigned to intravenous methylprednisolone (n = 839) at 2 mg/kg/d or placebo (n = 841) for 3 days adjunctive to endovascular thrombectomy. Main Outcomes and Measures The primary efficacy outcome was disability level at 90 days as measured by the overall distribution of the modified Rankin Scale scores (range, 0 [no symptoms] to 6 [death]). The primary safety outcomes included mortality at 90 days and the incidence of symptomatic intracranial hemorrhage within 48 hours. Results Among 1680 patients randomized (median age, 69 years; 727 female [43.3%]), 1673 (99.6%) completed the trial. The median 90-day modified Rankin Scale score was 3 (IQR, 1-5) in the methylprednisolone group vs 3 (IQR, 1-6) in the placebo group (adjusted generalized odds ratio for a lower level of disability, 1.10 [95% CI, 0.96-1.25]; P = .17). In the methylprednisolone group, there was a lower mortality rate (23.2% vs 28.5%; adjusted risk ratio, 0.84 [95% CI, 0.71-0.98]; P = .03) and a lower rate of symptomatic intracranial hemorrhage (8.6% vs 11.7%; adjusted risk ratio, 0.74 [95% CI, 0.55-0.99]; P = .04) compared with placebo. Conclusions and Relevance Among patients with acute ischemic stroke due to LVO undergoing endovascular thrombectomy, adjunctive methylprednisolone added to endovascular thrombectomy did not significantly improve the degree of overall disability.Trial RegistrationChiCTR.org.cn Identifier: ChiCTR210005172

Review and perspective of materials for flexible solar cells

Thin-film flexible solar cells are lightweight and mechanically robust. Along with rapidly advancing battery technology, flexible solar panels are expected to create niche products that require lightweight, mechanical flexibility, and moldability into complex shapes, such as roof-panel for electric automobiles, foldable umbrellas, camping tents, etc. In this paper, we provide a comprehensive assessment of relevant materials suitable for making flexible solar cells. Substrate materials reviewed include metals, ceramics, glasses, and plastics. For active materials, we focus primarily on emerging new semiconductors including small organic donor/acceptor molecules, conjugated donor/acceptor polymers, and organometal halide perovskites. For electrode materials, transparent conducting oxides, thin metal films/nanowires, nanocarbons, and conducting polymers are reviewed. We also discuss the merits, weaknesses, and future perspectives of these materials for developing next-generation flexible photovoltaics

Influence of Ventilation Duct Parameter Optimization on Pollutant Diffusion in Spiral Tunnels

The spiral tunnel could flexibly design the curvature and slope of the tunnel according to the geological structure, avoiding the adverse effect of complex terrain and topography, and had a strong advantage in engineering applications. Different from ordinary straight linear tunnels, spiral tunnels have a circular trend with obvious curvature and slope, which ensures certain differences between construction ventilation of the two types of tunnels, especially in terms of ventilation air flow field and pollutant diffusion. Relying on the actual spiral tunnel project, this paper studies the diffusion mechanism of ventilation pollutants in spiral tunnel construction. Optimization of the layout of the air duct based on numerical simulation and proposed pulsating ventilation method was performed to improve the ventilation and drainage effect of the tunnel. The time to reach the carbon monoxide concentration after blasting, and the dust concentration during the spraying process, were determined as indicators to measure the ventilation effect during the construction period. The hanging position of the air duct, the distance from the air duct outlet to the palm face, and the air speed were determined as the main factors affecting the ventilation effect. The main factors, the degree of influence and sensitivity of each influencing factor on the index, are studied, and the optimal air duct layout scheme suitable for the site is determined. The scheme can improve the ventilation effect and ventilation quality and provide effective reference for ventilation problems during the construction of other spiral tunnels. Meanwhile, more factors need to be examined to study the impact of pollutants in spiral tunnel construction, and physical models are needed to study the diffusion mechanism of pollutants in a spiral tunnel

Synthesis and Performance of Functionalized α-Zirconium Phosphate Modified with Octadecyl Isocyanate

The α-zirconium phosphate (α-ZrP) and hydrophobically modified α-zirconium phosphate (α-ZrP-I) were prepared. The grafting of octadecyl isocyanate was confirmed by Fourier transform infrared (FTIR) spectra, X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The dispersion of α-ZrP-I was studied by environmental scanning electron microscopy (SEM). The wettability of α-ZrP-I was determined by Kruss DSA30. Then, the effects of decompression and augmented injection of α-ZrP-I have been studied. The results of water flooding experiments show that the appropriate concentration of α-ZrP-I has an effect on the decrease of the water injection pressure

Influence of Ventilation Duct Parameter Optimization on Pollutant Diffusion in Spiral Tunnels

The spiral tunnel could flexibly design the curvature and slope of the tunnel according to the geological structure, avoiding the adverse effect of complex terrain and topography, and had a strong advantage in engineering applications. Different from ordinary straight linear tunnels, spiral tunnels have a circular trend with obvious curvature and slope, which ensures certain differences between construction ventilation of the two types of tunnels, especially in terms of ventilation air flow field and pollutant diffusion. Relying on the actual spiral tunnel project, this paper studies the diffusion mechanism of ventilation pollutants in spiral tunnel construction. Optimization of the layout of the air duct based on numerical simulation and proposed pulsating ventilation method was performed to improve the ventilation and drainage effect of the tunnel. The time to reach the carbon monoxide concentration after blasting, and the dust concentration during the spraying process, were determined as indicators to measure the ventilation effect during the construction period. The hanging position of the air duct, the distance from the air duct outlet to the palm face, and the air speed were determined as the main factors affecting the ventilation effect. The main factors, the degree of influence and sensitivity of each influencing factor on the index, are studied, and the optimal air duct layout scheme suitable for the site is determined. The scheme can improve the ventilation effect and ventilation quality and provide effective reference for ventilation problems during the construction of other spiral tunnels. Meanwhile, more factors need to be examined to study the impact of pollutants in spiral tunnel construction, and physical models are needed to study the diffusion mechanism of pollutants in a spiral tunnel

Uncertainty Quantification of Vibroacoustics with Deep Neural Networks and Catmull–Clark Subdivision Surfaces

This study proposes an uncertainty quantification method based on deep neural networks and Catmull–Clark subdivision surfaces for vibroacoustic problems. The deep neural networks are utilized as a surrogate model to efficiently generate samples for stochastic analysis. The training data are obtained from numerical simulation by coupling the isogeometric finite element method and the isogeometric boundary element method. In the simulation, the geometric models are constructed with Catmull–Clark subdivision surfaces, and meantime, the physical fields are discretized with the same spline functions as used in geometric modelling. Multiple deep neural networks are trained to predict the sound pressure response for various parameters with different numbers and dimensions in vibroacoustic problems. Numerical examples are provided to demonstrate the effectiveness of the proposed method