INTRODUCTION As a kind of common engineering structure, although there are many researches and practices for engineering design of transmission towers all over the world, windinduced collapse failures of transmission tower are still reported. According to the disaster investigation in the United States, Australia and South Africa, downburst is one of the main factors leading to the collapse of transmission towers. The reason is that damage may occur in some members of the tower subjected to the downburst, and eventually the damage accumulation may further lead to the failure of the tower. Therefore, many damage detection methods are proposed to prevent transmission tower from collapse. Albermani (1992 and 2002) predicted the collapse of the transmission tower by adopting nonlinear
In order to accurately explore the scientific layouts of glass bridges in tourist areas from the perspective of sustainable development, the literacy investigation method is applied and the obtained references are analyzed theoretically. The analysis results have shown that in terms of the scientific layouts of glass bridges, factors including topography and terrain, environmental capacity, tourist landscape perception, functional zoning and streamline design, integration of surrounding environment, tourist flow, styling and characteristic culture, detail design, safety issues, and tourist warnings are the key directions of the scientific layouts of the glass bridges. In summary, the scientific layouts of glass bridges in tourist areas from the perspective of sustainable development need to be considered at a very wide range; each direction is very important for the layouts of glass bridges; the layout design is a complete and complex systematic project. Therefore, the deep comprehension of the scientific layouts of the glass bridges would be referential to subsequent studies of the latecomers.
The method proposed in this paper identifies the loosen bolt of a transmission tower using the wavelet packet analysis and the neural net. First, the strain signal is measured. Second, the signal is decomposed by the wavelet packet (WP) analysis to extract the WP component energy, which is acted as the subset of the neural net. Finally, the loosen bolt is identified by the neural net. A three-level simple transmission tower is used as the experimental model, and the result show that the method can be effectively used to identify the loosen bolt of transmission tower.
Water bodies in urban parks are important for scenic and recreational areas, yet algal bloom problems seriously affect public use; therefore, it is important to study the features of algal density (AD) changes and environmental driving factors (EDFs) for water body management. In this study, five scenic water bodies in urban parks of Xinxiang City are taken as the objects for studying the AD and nine environmental indicators from March to October 2021, in accordance with time-series monitoring. The features of AD change in different layers of the water bodies are analyzed, and the main environmental impact factors of AD changes are screened by Pearson correlation analysis and principal components analysis (PCA), with main EDFs further extracted according to multiple linear regression analysis (MLRA), and multiple regression equation established. According to the data, ADs at different depth layers increase at first and then decrease with time, reaching the peak in August. According to the PCA, three principal components (PCs) are extracted in the 0.5 m and 1.0 m water layer, the variance contribution of which is 87.8% and 87.3%, respectively. The variance contribution of four PCs extracted in the 1.5 m water layer is 81.7%. After MLRA, it is found that the main EDFs of algal density in the 0.5 m water layer are electrical conductivity (EC), dissolved oxygen (DO), and water temperature (WT), in the 1.0 m water layer are WT and DO, and in the 1.5 m water layer are WT, DO, total nitrogen (TN), and EC. Generally speaking, WT and DO are decisive factors affecting AD. The EDFs’ leads to the AD changes in different water layers are analyzed, and it is proved that stratification occurs in scenic water bodies in urban parks. This study is expected to provide basic data and a theoretical basis for ecosystem system protection and water quality management of scenic water bodies in urban parks.
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