The influence of surface Rayleigh waves (SRWs) on the seismic behavior of three archetype nonconforming reinforced concrete (RC) buildings including weak first story with four, six, and eight stories when subjected to earthquake ground motions (EQGMs) recorded during the strong September 19, 2017 Mw7.1 earthquake in Mexico City, is discussed in this paper. For this purpose, ground acceleration time histories corresponding to the retrograde and prograde components of SRWs were extracted from EQGMs collected at the accelerographic stations placed at the transition and soft soil sites. It was found that the SWRs contribute to about 50% of the median maximum IDR demand (IDRmax) triggered by the as-recorded earthquake ground motions at the ground level of the four- and six-story building models, while their contribution is about 30% of IDRmax for the eight-story building model. It should be noted that that SRWs induce median IDRmax demands to the four-story building model larger than about 11% and 49% than those to the six- and eight-story models, respectively, for soft soil sites. Moreover, the prograde component can trigger IDRmax demands in the four-story building model larger than 73% and 45% than those for the six- and eight-story models, respectively, for the transition sites. Particularly, it was shown that SRWs induce median IDRmax demands in excess of 0.35% at the first level of the archetype building models, which is associated to the light cracking damage state of nonductile RC columns, and even in excess of IDRmax of 0.71% associated to the severe cracking damage state when the record-to-record variability is considered in the IDRmax demand (i.e. the 84th percentile of IDRmax). Although the earthquake ground motion component of the surface Rayleigh waves was negligible in the median IDRmax, this study showed that the effect of the directionality of IDRmax is important for the CH84 station, where significant polarity of spectral ordinates was identified in previous studies.

Airborne pesticide drift poses a substantial environmental threat in agriculture, affecting ecosystems far from the application sites. This process, in which up to 25% of applied pesticides are carried by air currents, can transport chemicals over hundreds or even thousands of kilometers. Drift rates peak during the summer months, reaching as high as 60%, and are influenced by various factors, including wind speed, temperature, humidity, and soil type. Pesticide volatilization is a significant concern, occurring 25 times more frequently than surface runoff. Under certain conditions, it can result in chemical losses of compounds like metolachlor and atrazine that are up to 150 times higher. These drifting pesticides have profound impacts on biodiversity, harming non-target plants, insects, fungi, and other organisms both near application sites and in distant ecosystems. Pesticide drift has been linked to over 50% reductions in wild plant diversity within 500 m of fields, reducing floral resources for pollinators. Despite growing evidence of these effects, the long-term consequences of airborne pesticides on biodiversity remain poorly understood, especially in complex field conditions with multiple pesticide applications. Addressing this requires urgent measures, such as improved meteorological tracking during applications, adoption of biopesticides, and integrated pest management strategies. This review highlights the pressing need for research to quantify airborne pesticides' ecological impacts, advocating for sustainable practices to mitigate environmental damage.

Insect infestation attacks in agricultural ecosystems are becoming more common because of global warming as well as farmland environmental circumstances, necessitating the development of new crop production technology. Pesticide application is one of the most common strategies for protecting the entire growing period of plants or shrubs against pests and pathogens in farms. The rapid, effective, and profitable application of plant control substances via unmanned aerial vehicle (UAV) crop spraying is anticipated to be a key new technique. When compared to ground spraying, UAV spraying saves chemicals, water, time, does not damage crop plants or balls of crop, and does not create soil compaction. When using UAV, pesticide drift and deposition must be managed in order to use pesticides safely, effectively, and efficiently. This paper focuses on agrochemical spraying by unmanned aerial vehicles and the key parameters that influence spray effectiveness, such as the operating parameters of nozzle type, flying speed, flight height, type of nozzle, and type of UAV model, for reducing drift and increasing application efficiency. The multirotor UAV is most suitable for spraying due to its fast operation, safety, not requiring a runway for takeoff and landing, and lower cost as compared to fixed-wing and VTOL. UAVs can also be used for crop disease identification, soil health monitoring, livestock monitoring, field mapping, etc. This paper aims to review the development of various UAV models, optimization of operating parameters, effect of nozzle on UAV spraying, characterization of droplet deposition, drift reduction technology, UAV-based remote sensing for plant protection, and cost comparison of UAV to conventional ground sprayer.

Large deformations of strata caused by shallow tunnel excavation in urban reclamation areas pose a serious threat to geological safety. In this paper, geo-mechanical model tests and numerical simulations were conducted to investigate the large deformation characteristics based on the Haicang tunnel in Xiamen, China. First, the tunnel excavation process using the double side drift method was simulated to reveal the large deformation characteristics and influencing factors. Then, geo-mechanical model tests were conducted to further investigate the deformation characteristics, stress release patterns and pore water pressure evolution. The results show that groundwater and the thickness of the backfill soil are the primary factors affecting the deformation behavior. Meanwhile, the stress release and pore water pressure dissipation resulting from the core construction procedure are direct causes of large deformation. The research results can serve as a reference for the prevention and control of large deformation in shallow buried tunnel construction.

Most existing seismic behavior analyses of underground structures simply consider a single earthquake. Meanwhile, the diaphragm wall, as an enclosure structure, is regarded as a security reserve and is always ignored in current studies. Herein, the characteristics of a diaphragm wall-subway station system with different connection modes under earthquake sequences were investigated using numerical simulation. The damage degree of the structural component was calculated through quantitative analysis of the tensile damage picture. The seismic damage level of the station structure was evaluated to characterize the damage transition effect induced by the aftershock according to the inter-story drift angle. Moreover, an empirical model for predicting the inter-story drift angle with respect to different peak accelerations was proposed. The research results indicate that the effect of the connection mode between the sidewall and the diaphragm wall on the damage evolution and deformation behavior of the station structure is significant. Compared with that of the compound wall structure, the seismic damage to the sidewall of the composite wall structure is much less severe, but the slabs become more vulnerable and suffer more severe damage. The accumulative damage triggered by aftershocks aggravates the extent of structural damage and even leads to damage transition. The conclusions illustrated in this paper contribute to a better understanding of the seismic resistance design of diaphragm wall-subway station systems under earthquake sequences.

All Nuclear power plants consist of several structures of varying importance that have to be designed for dynamic loading like earthquakes and impacts that they might be exposed to. Research on the influence of dynamic loading from blast events is still crucial to address to guarantee the general safety and integrity of nuclear plants. Conventional structural design approaches typically ignore the Soil-Structure Interaction (SSI) effect. However, studies show that the SSI effect is significant in structures exposed to dynamic loads such as wind and seismic loads. The present study is focused on evaluating the Soil-Structure Interaction effects on G + 11 storied reinforced concrete framed structure exposed to unconfined surface blast loads. The SSI effect for three flexible soil bases (i.e., Loose, Medium, and Dense) is evaluated by performing a Fast Non-linear (Time History) Analysis on a Two-Dimensional Finite Element Model developed in (Extended Three-Dimensional Analysis of Building System) ETABS software. Unconfined surface blast load of three different charge weights (i.e., 500 kg TNT, 1500 kg TNT, and 2500 kg TNT) at a standoff distance of 10 m are applied on the structure. Blast wave parameters are evaluated based on technical manual TM-5-1300. The blast response of the structure with and without the SSI effect is studied. It is concluded from this study that, there is a significant variation in dynamic response parameters of the structure with flexible soil bases compared to rigid or fixed base. For all magnitudes of surface blasts and soil base conditions, the ground floor is the most vulnerable floor against collapse. The study recommends measures to mitigate the damage due to unconfined surface blasts on multi-storey reinforced concrete structures.

Immersed tunnels, as a form of underwater transportation engineering offering numerous advantages, have been widely deployed in coastal and riverside cities. However, due to the shallow burial and underwater characteristics, immersed tunnels present significantly different surrounding soil and water environments compared to land-based tunnels. Currently, there is limited research on the seismic analysis of submarine immersed tunnels, raising questions about the direct application of the methods of land-based tunnels. In this study, the Davidenkov soil constitutive model is introduced to simulate the strong nonlinearity of deep sedimentary soil in marine areas. The Coupled Acoustic-Structure (CAS) method is employed to simulate the dynamic interaction between seawater and seabed. A time-history analysis model is developed to capture the coupling interactions between seawater, seabed, and tunnel structure. The effects of the soil-tunnel contact mode and seismic input method on the seismic responses of immersed tunnels are investigated in detail. Seismic response characteristics of immersed tunnels are analyzed from four perspectives: distribution of tensile damage in the tunnel, maximum inter-story drift ratio, maximum bending moment, and tunnel inclination angle in the cross-sectional direction. The results indicate that the overlying seawater and sand compaction piles negatively impact the seismic performance of immersed tunnels in the scenarios of this study. Furthermore, their impact pattern and extent are closely correlated with the intensity of the input seismic motion.

The objective of this study is to explore the seismic fragility of reinforced concrete bridges, specifically in response to the vertical components of ground motions, utilizing fragility surfaces. The examination of bridge responses involves the application of optimally selected intensity measures through three-dimensional nonlinear time-history analyses, encompassing uncertainties in both superstructure materials and soil-structure interaction effects. In this investigation, an extended Probabilistic Seismic Demand Model (e-PSDM) is employed, leveraging fragility surfaces to concurrently consider vertical and horizontal excitations. The results obtained from this approach are compared with traditional fragility curves. This study emphasizes Pile-cap displacement and drift ratio as pivotal engineering damage parameters, acknowledging their sensitivity to the influences of both soil-structure interaction effects and vertical ground motion. The fragility surfaces derived from the study reveal a correlation between increased vertical spectral accelerations and elevated probabilities of surpassing both slight damage and collapse limit states. These observations underscore the critical significance and practical utility of fragility surfaces in the context of performance-based seismic assessment and design for reinforced concrete bridges. The findings from this research contribute valuable insights into the nuanced behaviour of reinforced concrete bridges under seismic conditions, emphasizing the relevance of incorporating vertical components in fragility assessments for a more comprehensive understanding of structural vulnerability.

The utilization of mulch stands as a paramount approach in the management of wind erosion and the stabilization of soil and drifting sands. This study aimed to explore the impact of various concentrations of spent liquor (20 %, 30 %, and 50 % v/v) derived from SO2-ethanol-water (SEW) fractionation of Eucalyptus wood on the physical and mechanical properties of sand. These properties encompassed moisture content, thickness, temperature, electrical conductivity (EC), wind erodibility, penetration resistance, and seed germination. The findings revealed that the highest compressive strength (0.76 MPa) was attained with mulch consisting of 50 % SEW spent liquor, resulting in a 3.3-fold increase in penetration resistance compared to the control treatment. Furthermore, the 20 % concentration of spent liquor did not adversely affect the germination of black saxaul (Haloxylon ammodendron), whereas the lowest seed germination rate was associated with the 50 % concentration. Based on the measured parameters, the optimal mulch treatment for stabilizing drifting sands was identified as mulch with a 50 % (v/v) concentration. This study underscores the efficacy of SEW spent liquor in dust control and mitigating its environmental impacts, thus highlighting its potential in sustainable soil management practices.

Addition of microsilica improves the mechanical properties of mixtures containing Ca(OH)2 due to the chemical reaction between SiO2 in microsilica and Ca(OH)2 in the composition of prepared mixtures. This study aims to compare the efficiency of different microsilica-based mulches in sand stabilization. Several mixtures were prepared through combining microsilica with clay, lime, gypsum, and cement. Data were analyzed as a factorial experiment based on completely randomized design with treatments including: 1) mulch type: microsilica-clay-lime, microsilica-clay, microsilica-cement, microsilica-lime, microsilica-clay-gypsum, and microsilica-gypsum; 2) thickness: one- and two-layers, and 3) time (7 and 60 days) in 3 replications. Penetration resistance (PR), shear strength (SS), threshold friction velocity (V), and soil loss (SL) were measured. Results revealed that microsilica-clay-lime and microsilica-cement showed the highest PR (6.02 kgcm-2), SS (7.08 and 6.71 Ncm-2, respectively), and V (18.25 and 18.11 ms-1, respectively), and the lowest SL which makes them the most suitable mulches for sand stabilization.