To quantify the seismic resilience of buildings, a method for evaluating functional loss from the component level to the overall building is proposed, and the dual-parameter seismic resilience assessment method based on postearthquake loss and recovery time is improved. A three-level function tree model is established, which can consider the dynamic changes in weight coefficients of different category of components relative to their functional losses. Bayesian networks are utilized to quantify the impact of weather conditions, construction technology levels, and worker skill levels on component repair time. A method for determining the real-time functional recovery curve of buildings based on the component repair process is proposed. Taking a three-story teaching building as an example, the seismic resilience indices under basic earthquakes and rare earthquakes are calculated. The results show that the seismic resilience grade of the teaching building is comprehensively judged as Grade Ⅲ, and its resilience grade is more significantly affected by postearthquake loss. The proposed method can be used to predict the seismic resilience of buildings prior to earthquakes, identify weak components within buildings, and provide guidance for taking measures to enhance the seismic resilience of buildings.

To ensure the operational safety of railways in the landslide-prone areas of mountainous regions, a large-scale model test and numerical simulation were conducted to study the bending moment distribution, internal force distribution, deformation development, and crack propagation characteristics of a framed anti-sliding structure (FAS) under landslide thrust up to the point of failure. Results show that the maximum bending moment and its increase rate in the fore pile are greater than those in the rear pile, with the maximum bending moment of the fore pile approximately 1.1 times that of the rear pile. When the FAS fails, the displacement at the top of the fore pile is significantly greater, about 1.27 times that of the rear pile in the experiment. Major cracks develop at locations corresponding to the peak bending moments. Small transverse cracks initially appear on the upper surface at the intersection between the primary beam and rear pile and then spread to the side of the structure. At the failure stage, major cracks are observed at the pil-beam intersections and near the anchor points. Strengthening flexural stiffness at intersections where major cracks occur can improve the overall thrust-deformation coordination of the FAS, thereby maximizing its performance.

Polyethylene glycol (PEG) with different chains was used to modify epoxy asphalt. Molecular models of PEG-modified epoxy asphalt were developed using molecular simulations (MS). The thermodynamic and mechanical properties of PEG-modified epoxy asphalt were analyzed, and its toughening mechanisms were explored. A method based on the Dijkstra algorithm was proposed to evaluate epoxy asphalt crosslinked networks. The results show that the introduction of PEG chains into epoxy asphalt can lower the glass transition temperature and enhance its toughness because of the extended length of the PEG chains, which can increase the free volume and improve the mobility of the epoxy resin in the epoxy asphalt. The crosslinked network quantitative evaluation method based on the Dijkstra algorithm can effectively evaluate the distribution of epoxy asphalt crosslinking bonds, providing further explanation of the toughening mechanism of PEG-modified epoxy asphalt. The feasibility of designing and screening epoxy asphalt materials by MS is verified, and a guide for toughening mechanism research of epoxy asphalt at the molecular level is provided.

Main cable displacement-controlled devices (DCDs) are key components for coordinating the vertical deformation of the main cable and main girder in the side span of continuous suspension bridges. To reveal the mechanical action mechanisms of DCD on bridge structures, a three-span continuous suspension bridge was taken as the engineering background in this study. The influence of different forms of DCD on the internal force and displacement of the components in the side span of the bridge and the structural dynamic characteristics were explored through numerical simulations. The results showed that the lack of DCD caused the main cable and main girder to have large vertical displacements. The stresses of other components were redistributed, and the safety factor of the suspenders at the side span was greatly reduced. The setting of DCD improved the vertical stiffness of the structure. The rigid DCD had larger internal forces, but its control effect on the internal forces at the side span was slightly better than that of the flexible DCD. Both forms of DCD effectively coordinated the deformation of the main cable and main girder and the stress distribution of components in the side span area. The choice of DCD form depends on the topographic factors of bridge sites and the design requirements of related components at the side span.

References

To investigate the wind-induced vibration response characteristics of multispan double-layer cable photovoltaic (PV) support structures, wind tunnel tests using an aeroelastic model were carried out to obtain the wind-induced vibration response data of a three-span four-row double-layer cable PV support system. The wind-induced vibration characteristics with different PV module tilt angles, wind speeds, and wind direction angles were analyzed. The results showed that the double-layer cable large-span flexible PV support can effectively control the wind-induced vibration response and prevent the occurrence of flutter under strong wind conditions. The maximum value of the wind-induced vibration displacement of the flexible PV support system occurs in the windward first row. The upstream module has a significant shading effect on the downstream module, with a maximum effect of 23%. The most unfavorable wind direction angles of the structure are 0° and 180°. The change of the wind direction angle in the range of 0° to 30° has little effect on the wind vibration response. The change in the tilt angle of the PV modules has a greater impact on the wind vibration in the downwind direction and a smaller impact in the upwind direction. Special attention should be paid to the structural wind-resistant design of such systems in the upwind side span.

To tackle the issue of notch frequency and center frequency drift of the L(0,1) mode guided wave in ultrasonic guided wave-based stress monitoring of prestressed steel strands, a method using higher-order mode plateau frequencies is adopted. First, the correlation between group velocity peaks and phase velocities at these plateau frequencies is analyzed. This analysis establishes a quantitative relationship between phase velocity and stress in the steel strand, providing a theoretical foundation for stress monitoring. Then the two-dimensional Fourier transform is employed to separate wave modes. Dynamic programming techniques are applied in the frequency-velocity domain to extract higher-order modes. By identifying the group velocity peaks of these separated higher-order modes, the plateau frequencies of guided waves are determined, enabling indirect measurement of stress in the steel strand. To validate this method, finite element simulations are conducted under three scenarios. Results show that the higher-order modes of transient signals from three different positions can be accurately extracted, leading to successful cable stress monitoring. This approach effectively circumvents the issue of guided wave frequency drift and improves stress monitoring accuracy. Consequently, it significantly improves the application of ultrasonic guided wave technology in structural health monitoring.

References

The fuzzy comfortability of a wind-sensitive super-high tower crane is critical to guarantee occupant health and improve construction efficiency. Therefore, the wind-resistant fuzzy comfortability of a super-high tower crane in the Ma’anshan Yangtze River (MYR) Bridge site is analyzed in this paper. First, the membership function model that represents fuzzy comfortability is introduced in the probability density evolution method (PDEM). Second, based on Fechner’s law, the membership function curves are constructed according to three acceleration thresholds in ISO 2631. Then, the fuzzy comfortability for the super-high tower crane under stochastic wind loads is assessed on the basis of different cut-set levels λ. Results show that the comfortability is over 0.9 under the required maximum operating wind velocity. The low sensitivity to λ can be observed in the reliability curves of ISO Ⅱ and Ⅲ membership functions. The reliability of the ISO Ⅰ membership function is not sensitive to λ when λ < 0.7, whereas it becomes sensitive to λ when λ > 0.7.

Practical applications of desulfurization gypsum are limited owing to its brittleness and low strength. To overcome these challenges, researchers have developed engineered desulfurization gypsum composites (EDGCs) by incorporating ultrahigh molecular weight polyethylene (UHMWPE) fiber and sulfoaluminate cement (SAC). The mix ratio was optimized using response surface methodology (RSM). Experimental testing of EDGC under compressive and tensile loads led to the creation of a regression model that investigates the influence of variables and their interactions on the material’s compressive and tensile strengths. Additionally, microscopic morphology and hydration product composition were analyzed to explore the influence mechanism. The results indicated that EDGC’s compressive strength increased by up to 38.4% owing to a decreased water-binder ratio and higher SAC content. Similarly, tensile strength increased by up to 38.6% owing to increased SAC and fiber content. Moreover, EDGC demonstrated excellent strain-hardening behavior and multiple cracking characteristics, achieving a maximum tensile strain of nearly 3%. The research findings provide valuable insights for optimizing the performance of desulfurization gypsum.

Currently, the BeiDou-3 (BDS-3) precise point positioning (PPP) service (PPP-B2b) mostly employs the ionosphere-free (IF) combination model for precise timing, which tends to amplify the noise in observation values. To address this issue, this paper proposes a real-time BDS-3 precise unidirectional timing model based on uncombined (UC) observations using the BDS-3 PPP-B2b service. This model resolves the challenge of the amplified observation noise inherent in the IF combination model. The experiment involved selecting eight global navigation satellite system (GNSS) observation stations within China and collecting continuous observation data for 15 d. A comparative analysis with the traditional dual-frequency IF combination PPP timing model showed that the BDS-3 UC PPP timing based on the BDS-3 PPP-B2b service can achieve a timing precision of 0.5 ns. In addition, it was found that due to global positioning system (GPS) satellite clock products in the BDS-3 PPP-B2b service not being unified to the standard time, the GPS IF PPP timing method based on the BDS-3 PPP-B2b service is not recommended for precise timing. In summary, the BDS-3 UC PPP timing model proposed in this paper is suitable for precise timing, providing observation values with smaller noise, and its timing accuracy is comparable to that of the BDS-3 IF PPP, with slightly better frequency stability.

A programmable low-profile array antenna based on nematic liquid crystals (NLCs) is proposed. Each antenna unit comprises a square patch radiating structure and a tunable NLC-based phase shifter capable of achieving a phase shift exceeding 360° with high linearity. First, the above 64 antenna units are periodically arranged into an 8 × 8 NLC-based antenna array, and the bias voltage of the NLC-based phase shifter loaded on the antenna unit is adjusted through the control of the field-programmable gate array (FPGA) programming sequences. This configuration enables precise phase changes for all 64 channels. Numerical simulation, sample processing, and experimental measurements of the antenna array are conducted to validate the performance of the antenna. The numerical and experimental results demonstrate that the proposed antenna performs well within the frequency range of 19.5-20.5 GHz, with a 3 dB relative bandwidth of 10% and a maximum main lobe gain of 14.1 dBi. A maximum scanning angle of ±34° is achieved through the adjustment of the FPGA programming sequence. This NLC-based programmable array antenna shows promising potential for applications in satellite communication.

A new method based on the iterative adaptive algorithm (IAA) and blocking matrix preprocessing (BMP) is proposed to study the suppression of multi-mainlobe interference. The algorithm is applied to precisely estimate the spatial spectrum and the directions of arrival (DOA) of interferences to overcome the drawbacks associated with conventional adaptive beamforming (ABF) methods. The mainlobe interferences are identified by calculating the correlation coefficients between direction steering vectors (SVs)and rejected by the BMP pretreatment. Then, IAA is subsequently employed to reconstruct a sidelobe interference-plus-noise covariance matrix for the preferable ABF and residual interference suppression. Simulation results demonstrate the excellence of the proposed method over normal methods based on BMP and eigen-projection matrix perprocessing (EMP) under both uncorrelated and coherent circumstances.

The presence of circles in the network maximum flow problem increases the complexity of the preflow algorithm. This study proposes a novel two-stage preflow algorithm to address this issue. First, this study proves that at least one zero-flow arc must be present when the flow of the network reaches its maximum value. This result indicates that the maximum flow of the network will remain constant if a zero-flow arc within a circle is removed; therefore, the maximum flow of each network without circles can be calculated. The first stage involves identifying the zero-flow arc in the circle when the network flow reaches its maximum. The second stage aims to remove the zero-flow arc identified and modified in the first stage, thereby producing a new network without circles. The maximum flow of the original looped network can be obtained by solving the maximum flow of the newly generated acyclic network. Finally, an example is provided to demonstrate the validity and feasibility of this algorithm. This algorithm not only improves computational efficiency but also provides new perspectives and tools for solving similar network optimization problems.

To explore the electrostatic discharge behavior of charged powders in industrial silos, discharge experiments are conducted based on a full-size industrial silo discharge platform. Electrostatic discharge mode, frequency, and energy are investigated for powders of different polarities. Although the powders have low charge-to-mass ratios (+0.087 μC/kg for the positively charged powders and -0.26 μC/kg for the negatively charged ones), electrostatic discharges occur approximately every 10 s, with the maximum discharge energy being 800 mJ. Powder polarity considerably influences discharge energy. The positive powders exhibit higher discharge energy than the negative ones, although discharge frequency remains similar for both. Effects of powder charge, humidity, and mass flow on discharge frequency and discharge energy are quantitatively analyzed, providing important insights for the improvement of safety in industrial powder handling.

A reasonable process plan is an important basis for implementing wire arc additive and subtractive hybrid manufacturing (ASHM), and a new optimization method is proposed. Firstly, the target parts and machining tools are modeled by level set functions. Secondly, the mathematical model of the additive direction optimization problem is established, and an improved particle swarm optimization algorithm is designed to decide the best additive direction. Then, the two-step strategy is used to plan the hybrid manufacturing alternating sequence. The target parts are directly divided into various processing regions; each processing region is optimized based on manufacturability and manufacturing efficiency, and the optimal hybrid manufacturing alternating sequence is obtained by merging some processing regions. Finally, the method is used to outline the process plan of the designed example model and applied to the actual hybrid manufacturing process of the model. The manufacturing result shows that the method can meet the main considerations in hybrid manufacturing. In addition, the degree of automation of process planning is high, and the dependence on manual intervention is low.

China’s healthcare system faces increasing challenges, including surging medical costs, resource allocation imbalances favoring large hospitals, and ineffective referral mechanisms. The lack of a unified strategy integrating standardized coverage with personalized payment compounds these issues. To this end, this study proposes a risk-sharing reform strategy that combines equal coverage for the same disease (ECSD) with an individualized out-of-pocket (I-OOP) model. Specifically, the study employs a Markov model to capture patient transitions across health states and care levels. The findings show that ECSD and I-OOP enhance equity by standardizing disease coverage while tailoring costs to patient income and facility type. This approach alleviates demand on high-tier hospitals, promoting primary care utilization and enabling balanced resource distribution. The study’s findings provide a reference for policymakers and healthcare administrators by presenting a scalable framework that is aligned with China’s development goals with the aim of fostering an efficient, sustainable healthcare system that is adaptable to regional needs.