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It is a common problem that the glass panel falls due to the damage of silicone structural sealant used for the connection of the hidden frame glass curtain walls in the service life of the curtain walls. Most of the existing studies used dynamics methods to detect the debonding damage of curtain walls. However, these methods usually require additional load excitation, and the measured dynamic response data are susceptible to environmental noise, which makes it difficult to achieve reliable assessment of the safety condition of curtain walls. In order to solve the above problems, this paper proposes a method to detect the debonding damage of curtain wall units by using the deflection and rotation angles of the glass panel under the action of negative wind pressure. First, a series of debonding damage experiments of hidden frame glass curtain wall are designed to verify the feasibility of using deflection and rotation angle to detect the safety state of the curtain wall under wind load. Then, based on the experimental results, a safety risk monitoring system for hidden frame glass curtain walls is proposed, which can realize the real-time monitoring of curtain wall units and conduct rapid ide.pngication of debonding damage.

Aiming at the issue of large CPU costs and low calculation accuracy in the design of right-angle fasteners in scaffolding structures, prediction models of fastener anti-slip performance and torsion performance based on machine learning are proposed. A three-dimensional solid model of right-angle fasteners is established using the finite element method, the effectiveness of the numerical simulation method is verified through test results, and the comprehensive influence of various design parameters on the performance of fasteners is revealed by the parametric analysis method. The database is established by combining the test and numerical simulation results, and the fastener stiffness prediction models are proposed based on random forest (RF), support vector machine (SVM) and K-most proximity algorithm (K-NN), respectively. The expressions for the measured point displacement of the anti-slip model and the stiffness prediction of the torsion model are proposed in combination with genetic expression programming. The results indicate that SVM and GEP can predict the displacement and torsional stiffness of right-angle fasteners more accurately, which is important for guiding the safety design of fasteners in engineering scaffolding structures.

BackgroundWater is the primary resource required for the exploitation of lunar resources. Investigating the distribution of water on the surface of the moon has become a focal point in the lunar exploration plans of several nations.PurposeThis study aims to quantify the presence of hydrogen and analyze its spatial distribution on the lunar surface using data from the Chang'E-2 gamma-ray spectrometer (CE2-GRS).MethodsFirstly, an analytical method combining branch specific stripping with the nonlinear least-square fitting Gaussian function was proposed to subtract the characteristic γ rays of interfering nuclides (214Bi@2.204 MeV, 27Al@2.210 MeV, 49Ca@2.371 MeV) ranging from 2.1 MeV to 2.5 MeV. Then, a characteristic function between the abundance and counts of aluminum γ rays around the moon was established to subtract the counts of aluminum in the mixed peak. Finally, the spatial distribution of hydrogen γ rays for counts per 3 s on the whole lunar surface was obtained.ResultsThe analysis results show that high-value characteristics exhibited in some areas, including the Aiken basin, Mare Ingenii, Mare Imbrium, and Oceanus Procellarum, are approximately 2.6 times the average value of hydrogen counts among the 14 major maria. Comparison between the distribution characteristics of hydrogen elements on the lunar surface and the data of epithermal neutrons from Lunar Prospector (LP) reveals a highly negative correlation between the distribution characteristics of the two in these regions.ConclusionsThe distribution characteristics of hydrogen elements on the lunar surface further predict that there may be a large amount of structural water in the Mare Ingenii, Mare Imbrium, and Oceanus Procellarum, formed by the combination of hydroxyl groups or molecular hydrogen (H2), achieving a better understanding of the orbit γ deep mining and scientific application of energy spectrum data.

The infill wall has a significant influence on the progressive collapse resistance of the precast concrete (PC) frame, and there is no corresponding design method at present. In order to obtain a reliable calculation method for progressive collapse, a numerical and analytical analysis of progressive collapse resistance of PC frames with infill walls was conducted. According to the 3∶1 scale test of PC frames with and without infill walls after removing middle column, and considering the displacement of middle column under the asymmetric distribution of infill walls, a mechanical model based on equivalent strut was established by introducing asymmetry coefficient. Based on the finite element (FE), numerical models of the sub frames with the asymmetric infill walls were established, and displacement-load curves of the middle column were obtained, based on which, the analytical solutions were compared with the test results of bare, double, and single infill wall PC frames, and the results were found in good agreement. A comparison of the calculation results with the recommended values in current codes indicates that the displacement of PC frames under the peak load of catenary is increased when considering the infill wall. The recommended value of the displacement, whose middle column is 0.2 times of the span, is suitable for the bare PC frames, but conservative for the PC frames with infill walls. The results provide a basis for the calculation of the progressive collapse resistance of PC frames with infill walls.

Objectives: This study aimed to investigate the factors influencing the short‐term and long‐term efficacy of sclerotherapy for cystic thyroid nodules. Methods: Ninety‐nine cystic thyroid nodules that underwent ultrasound‐guided fine‐needle aspiration biopsy, detection of thyroglobulin in fine needle aspirate (Tg‐FNA), and ultrasound‐guided percutaneous lauromacrogol injection were retrospectively enrolled from July 2018 to July 2021. All nodules were followed up at 3 and 12 months after the procedure. Factors related to lauromacrogol injection efficacy, including initial volume, vascularity, pathological types, and Tg‐FNA level, were analyzed. The nodules were classified as non‐effective (VRR <50%) and effective groups (VRR ≥50%) at 3 months to evaluate short‐term prognosis, and non‐cured (VRR <90%) and cured groups (VRR ≥90%) at 12 months to evaluate long‐term prognosis. Results: The volume of cystic thyroid nodules tended to shrink during follow‐up. The resolution rate was 79.80% (79/99) at 3 months and 96.91% (94/97) at 12 months. The cure rate was 80.41% (78/97) at 12 months. Independent factors for the long‐term prognosis included Tg‐FNA level and vascularity (P <.05). Only Tg‐FNA level was an independent factor for the short‐term prognosis (P <.05). The area under the receiver operating characteristic curve for assessing the efficacy at 3 months was 0.79 (95% confidence interval [CI]: 0.65–0.89). With a cutoff value of Tg‐FNA 126.92 ng/mL, the specificity was 0.70, and the sensitivity was 0.85. Conclusions: Ultrasound‐guided percutaneous lauromacrogol injection is an effective treatment option for cystic thyroid nodules. It is less effective in viscous or vascular predominantly cystic nodules. [ABSTRACT FROM AUTHOR]