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In recent years, the damage caused by thrips has become a key factor impacting the winter and spring production of fruits and vegetables in Hainan Province, China. This study aimed to elucidate the effects of different pupation environments on pupal development and eclosion of chilli thrips (Scirtothrips dorsalis Hood) by analyzing pupal development and eclosion of chilli thrips in an indoor environment with simulated natural soils and water content. Soil type, soil water content, and temperature substantially affected the eclosion of chilli thrips during the pupal stage. Both a low soil water content of 1% and a high soil water content of 15% were not conducive to the pupation and eclosion of chilli thrips. Moreover, the results indicated an interaction between soil type and soil water and temperature and soil water content, affecting the eclosion of chilli thrips. Chilli thrips not only pupated in soil but also completed pupation and eclosion in other soil-less environments, such as tender mango leaves, stalks, plastic mulch, and weed fabric. This study suggests that in addition to adopting pest control measures that target the canopy layer of crops, appropriate measures such as increasing soil water content can also be implemented in the ground layer to enhance the overall effectiveness of pest control.

期刊论文 2024-12-12 DOI: 10.1093/ee/nvae123 ISSN: 0046-225X

Vegetation reinforcement is considered to be an environmentally friendly measure for slope improvement, which helps to prevent shallow landslides through roots' mechanical and hydrologic reinforcements. This study focuses on the mechanical reinforcement of the seedling roots of Ficus virens, a rich root system that is widely grown in the southern parts of China. Triaxial tests on the root-soil composite were carried out in silty clay and mixed soils to investigate the effects of root morphologies, including its layout and distribution angle of the main and lateral roots, on the stress-strain relationship, build-up of excess pore water pressure, and stress path. The test results indicate that two types of the soil reinforced by a curved main root and horizontal lateral root (CH) are proved to be the optimal scheme for yielding the best root reinforcement effect. Based on this scheme, the shear strength parameters are determined by fitting a straight-line tangent to Mohr circles under different cell pressures. It is found that soil shear strength is significantly improved by root reinforcement, with the root effect principally on soil cohesion, increasing up to 10 kPa, and negligible on internal friction angle. A modified equation is proposed for characterizing the critical state line of the rooted soil, and an additional cohesion term is proven to be valid for representing the root reinforcement. Different types of failure mechanism are observed in silty clay and mixed soils with/without roots. The findings provide novel insights into the shearing behavior of rooted soil and theoretical evidence for the improvement of slopes reinforced by Ficus virens.

期刊论文 2024-11-01 DOI: 10.1016/j.catena.2024.108407 ISSN: 0341-8162

During strong earthquakes, pounding may occur on large-span bridges and their approach bridges. The effect and mitigation measures of such pounding have rarely been explored in previous studies. This paper primarily uses finite element models to investigate the pounding effects at the expansion joints between the main cable-stayed bridge and its approach bridge. Friction pendulum bearings (FPBs) and fluid viscous dampers (FVDs) are used to alleviate poundings. Furthermore, a detailed analysis is conducted on how the pounding effect of the isolated main bridge with FPBs and FVDs is affected by the wave passage effect, ground motion type, and soil type. This study reveals that FPBs and FVDs can effectively reduce pounding effects and the associated risks. Even with the installation of FPBs and FVDs, lower seismic wave velocities and near-fault seismic motions with pulse effects can significantly increase the pounding effects between the cable-stayed bridge and its approach bridge.

期刊论文 2024-07-01 DOI: 10.3390/app14146220

Some soil characteristics, such as the shear wave velocity, the shear modulus, the Poisson ratio, and the porosity, affect how clay soils behave. The soil design parameters under loading, such as soil liquefaction induced by dynamic earthquake loading, employ the shear wave velocity and shear module with modest stress. In order to understand the pore saturation, the Poisson ratio and seismic velocity ratio are also utilized. Additionally, one of the most crucial physical characteristics for assessing permeability at the base of any engineering structure, resolving consolidation issues that may arise at the foundation of an engineering structure, and influencing the deformation behavior of soils is soil porosity. Predicting the porosity of clay soils is a crucial first step in tackling engineering and environmental issues that may arise in the soil after an earthquake or not. With the use of dynamic soil metrics such as seismic velocities, shear modules, bulk modules, seismic velocity ratios, and Poisson ratios, the current work aims to estimate soil porosity. Seismic refraction was used by various studies in the past to conduct in-situ geophysical research. The lithological characteristics of the soil (such as the grain size, shape, type, compaction, consolidation, and cementation of the grains) and the physical characteristics of the soil (such as porosity, permeability, density, anisotropy, saturation level, liquid-solid transition, pressure, and temperature), as well as the elasticity characteristics of the soil (such as shear modulus (G), bulk modulus (K), Young modulus (E), Poisson ratio (mu) and Lame constants (lambda) all have an impact on seismic waves passing through a medium.

期刊论文 2024-06-01 DOI: 10.1007/s11600-023-01180-8 ISSN: 1895-6572

Unpreventable constructional defects are the main issues in the case of steel Moment-Resisting Frames (MRFs) that mostly occur in the rigidities of beam-to-column connections. The present article aims to investigate the effects of different rigidities of structures and to propose Infill Masonry Walls (IMWs) as retrofitting strategy for the steel damaged buildings. A fault or failure to meet a certain consideration of the soil type beneath the building and the current rigidity of connections can cause mistake in determining the performance of building. Therefore, this study comprehensively explores different conditions of soil types, connection rigidities, and implementing IMWs on the 3-, 5-, 7-, and 9-story MRFs. Two nonlinear analyses, namely Nonlinear Dynamic Analysis (NDA) and Incremental Dynamic Analysis (IDA) were performed on 384 steel MRFs having different conditions of defects and the results of the analysis include 3456 performance curves assuming three ground motion subsets recommended by FEMA P695. The results confirm that the proposed retrofitting procedure can effectively improve the performance levels of MRFs, which the connections rigidity of 90 %, 80 %, 70 %, 60 %, and 50 % can reduce the collapse performance level by 2.86 %, 5.35 %, 9.31 %, 16.56 %, and 34.65 %, respectively.

期刊论文 2024-02-01 DOI: 10.1016/j.soildyn.2023.108396 ISSN: 0267-7261
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