Ensuring the accuracy of free-field inversion is crucial in determining seismic excitation for soil-structure interaction (SSI) systems. Due to the spherical and cylindrical diffusion properties of body waves and surface waves, the near-fault zone presents distinct free-field responses compared to the far-fault zone. Consequently, existing far-fault free-field inversion techniques are insufficient for providing accurate seismic excitation for SSI systems within the near-fault zone. To address this limitation, a tailored near-fault free-field inversion method based on a multi-objective optimization algorithm is proposed in this study. The proposed method establishes an inversion framework for both spherical body waves and cylindrical surface waves and then transforms the overdetermined problem in inversion process into an optimization problem. Within the multi-objective optimization model, objective functions are formulated by minimizing the three-component waveform differences between the observation point and the delayed reference point. Additionally, constraint conditions are determined based on the attenuation property of propagating seismic waves. The accuracy of the proposed method is then verified through near-fault wave motion characteristics and validated against real downhole recordings. Finally, the application of the proposed method is investigated, with emphasis on examining the impulsive property of underground motions and analyzing the seismic responses of SSI systems. The results show that the proposed method refines the theoretical framework of near-fault inversion and accurately restores the free-field characteristics, particularly the impulsive features of near-fault motions, thereby providing reliable excitation for seismic response assessments of SSI systems.

Char and soot represent distinct types of elemental carbon (EC) with varying sources and physicochemical properties. However, quantitative studies in sources, atmospheric processes and light-absorbing capabilities between them remain scarce, greatly limiting the understanding of EC's climatic and environmental impacts. For in-depth analysis, concentrations, mass absorption efficiency (MAE) and stable carbon isotope were analyzed based on hourly samples collected during winter 2021 in Nanjing, China. Combining measurements, atmospheric transport model and radiative transfer model were employed to quantify the discrepancies between char-EC and soot-EC. The mass concentration ratio of char-EC to soot-EC (R-C/S) was 1.4 +/- 0.6 (mean +/- standard deviation), showing significant dependence on both source types and atmospheric processes. Case studies revealed that lower R-C/S may indicate enhanced fossil fuel contributions, and/or considerable proportions from long-range transport. Char-EC exhibited a stronger light-absorbing capability than soot-EC, as MAE(char) (7.8 +/- 6.7 m(2)g(-1)) was significantly higher than MAE(soot) (5.4 +/- 3.4 m(2)g(-1))(p < 0.001). Notably, MAE(char) was three times higher than MAE(soot) in fossil fuel emissions, while both were comparable in biomass burning emissions. Furthermore, MAE(soot) increased with aging processes, whereas MAE(char) exhibited a more complex trend due to combined effects of changes in coatings and morphology. Simulations of direct radiative forcing (DRF) for five sites indicated that neglecting the char-EC/soot-EC differentiation could cause a 10 % underestimation of EC's DRF, which further limit accurate assessments of regional air pollution and climate effects. This study underscores the necessity for separate parameterization of two types of EC for pollution mitigation and climate change evaluation.

Intervertebral disc degeneration (IVDD) is a globally prevalent disease, yet achieving dual repair of tissue and function presents significant challenges. Considering reactive oxygen species (ROS) is a primary cause of IVDD, and given the decrease of nucleus pulposus cells (NPCs) and extensive degradation of extracellular matrix (ECM) during IVDD development, the present study, inspired by the seeds-and-soil strategy, has developed NPCsloaded TBA@Gel&Chs hydrogel microspheres. These microspheres serve as exogenous supplements of NPCs and ECM analogs, replenishing seeds and soil for nucleus pulposus repair, and incorporating polyphenol antioxidant components to interrupt the oxidative stress-IVDD cycle, thereby constructing a microsphere system where NPCs and ECM support each other. Experiments proved that TBA@Gel&Chs exhibited significant extra-cellular ROS-scavenging antioxidant capabilities while effectively upregulating intracellular antioxidant proteins expression (Sirt3 and Sod2). This dual-action antioxidant capability effectively protects the vitality and physiological functions of NPCs. The therapeutic effects of microspheres on IVDD were also confirmed in rat models, which was found significantly restore histological structure and mechanical properties of degenerated discs. Additionally, RNA-seq results have provided evidences of antioxidant mechanism by which TBA@Gel&Chs protected NPCs from oxidative stress. Therefore, the NPCs-loaded TBA@Gel&Chs microspheres developed in this study have achieved excellent therapeutic effects, offering a paradigm using antioxidant biomaterials combined with cellular therapy for IVDD treatment.

Mesh-free methods, such as the Smooth Particle Hydrodynamics (SPH) method, have recently been successfully developed to model the entire wetting-induced slope collapse process, such as rainfall-induced landslides, from the onset to complete failure. However, the latest SPH developments still lack an advanced unsaturated constitutive model capable of capturing complex soil behaviour responses to wetting. This limitation reduces their ability to provide detailed insights into the failure processes and to correctly capture the complex behaviours of unsaturated soils. This paper addresses this research gap by incorporating an advanced unsaturated constitutive model for clay and sand (CASM-X) into a recently proposed fully coupled seepage flow-deformation SPH framework to simulate a field-scale wetting-induced slope collapse test. The CASM-X model is based on the unified critical state constitutive model for clay and sand (CASM) and incorporates a void-dependent water retention curve and a modified suction-dependent compression index law, enabling the accurate prediction various unsaturated soil behaviours. The integration of the proposed CASM-X model in the fully coupled flow deformation SPH framework enables the successful prediction of a field-scale wetting-induced slope collapse test, providing insights into slope failure mechanisms from initiation to post-failure responses.

Soil-plant-atmosphere interaction (SPAI) plays a significant role on the safety and serviceably of geotechnical infrastructure. The mechanical and hydraulic soil behaviour varies with the soil water content and pore water pressures (PWP), which are in turn affected by vegetation and weather conditions. Focusing on the hydraulic reinforcement that extraction of water through the plant roots offers, this study couples advances in ecohydrological modelling with advances in geotechnical modelling, overcoming previous crude assumptions around the application of climatic effects on the geotechnical analysis. A methodology for incorporating realistic ecohydrological effects in the geotechnical analysis is developed and validated, and applied in the case study of a cut slope in Newbury, UK, for which field monitoring data is available, to demonstrate its successful applicability in boundary value problems. The results demonstrate the positive effect of vegetation on the infrastructure by increasing the Factor of Safety. Finally, the effect of climate change and changes in slope vegetation cover are investigated. The analysis results demonstrate that slope behaviour depends on complex interactions between the climate and the soil hydraulic properties and cannot be solely anticipated based on climate data, but suctions and changes in suction need necessarily to be considered.

Excessive phosphorus emissions can result in the eutrophication of water bodies, causing severe environmental damage as well as influencing the efficiency of water treatment equipment. The impacts of carbon/phosphorus ratios on performance and mechanism of the upflow anaerobic sludge bed reactor remain unclear. Henrie, the effects of different carbon/phosphorus ratios (i.e., 80:1, 40:1, and 20:1) on the transformation of phosphorus in the biological treatment process of an upflow anaerobic sludge blanket (UASB) reactor were studied. The results showed that phosphines are of great importance in the phosphate reduction process. After a stable operation, the phosphine reached the highest 81.91 mg/m3 at a C/P ratio of 40:1. It was proved that the optimum operating condition of the reactor was carbon to phosphorus ratio of 40:1. Phosphate-reducing bacteria were present in the UASB reactor, and the relative abundance of Clostridia in the sludge was 1.90 % and 1.59 % when the C/P was 80:1 and 20:1, respectively. This implied that the low carbon to phosphorus ratio reduces the phosphorusreducing microbial activity in the reactor. Lower C/P values could inhibit the uptake and use of P in the phosphonate transport system and the transport of phosphate in the cell by the microbial Pst system, impeding the mineralization of organophosphates. The study provides new insights into improving the efficiency of treating phosphorus-rich wastewater.

Predicting cumulative surface slope displacements induced by rainfall infiltration is crucial for accurately assessing the risks to potentially affected infrastructure. In this paper the numerical modelling of the case history of Miscano slope is presented. Plaxis 2D code has been used adopting two constitutive laws: the linear elastoplastic model (Mohr-Coulomb, MC) and the Hardening Soil with small strain stiffness (HSsmall). The aim is to test the suitability of these constitutive laws in predicting the hydro-mechanical behaviour of clayey soil slope. Based on long-term field measurements, the parameters of MC and HSsmall have been determined by back analysing the first-year field measurements in terms of cumulative surficial horizontal displacements and pore water pressure. Subsequently, the numerical models have been validated against the analogous field measurements collected from the second year. The numerical models predict with a good agreement the field measurements for both years. In terms of cumulative surficial horizontal displacements, the HSsmall underestimates the field measurements by 21.2% at the end of the first year, while that based on MC exhibits a 32.8% overestimation. Moreover, the initialization procedure clearly affects the cumulative surficial horizontal displacements results obtained with both the HSsmall and MC models for the second year. In fact, the best results have been achieved when the second-year net rainfall have been applied starting from the initial phase used to generate the lithostatic stress state.

A novel iron-based phosphate cement (IPC), derived from iron-rich smelting slag (ISS), was developed as a sustainable and efficient binder for the stabilization/solidification of trivalent chromium (Cr3+). The mechanical properties, hydration behavior, microstructure, leaching toxicity, chromium chemical forms, and environmental safety of chromium-stabilized iron phosphate cement (CIPC) were thoroughly evaluated. The results showed that, with a mass ratio of ISS to ammonium dihydrogen phosphate (ADP) of 2.0, and even with the addition of 20 % chromium nitrate nonahydrate (CN), the compressive strength of CIPC reached 4.2 MPa after curing for 28 d. Furthermore, chromium leaching was well below 1 mg/L, significantly lower than the GB 5085.3-2007 standard limit of 15 mg/L, demonstrating the effective encapsulation of Cr3+ due to IPC's high early strength. In the IPC system, Cr3+ was primarily stabilized by forming CrPO4 and CrxFe1-x(OH)3 co-precipitates, which were further solidified through the physical encapsulation of IPC hydration products, such as (NH4)2Fe(PO3OH)2 center dot 4H2O, (NH4) (Mg,Ca)PO4 center dot H2O, and FePO4. This process resulted in a solidification efficiency of up to 99 %. BCR analysis confirmed that more than 98 % of the chromium in the CIPC remained in a stable residual form. Finally, the ecological risk index (PERT) was found to be 23.52, far below the safety threshold of 150, indicating the solidified material's long-term environmental safety. This study provides an innovative approach for the reutilization of ISS while effectively stabilizing/solidifying chromium.

Cyclic spherical stresses are prevalent in dynamic stress fields and significantly influence the dynamic behavior of loess, a material characterized by high compressibility and anisotropy. Previous research has primarily focused on shear stresses, often overlooking the impact of spherical stresses. This study investigated the deformation induced by cyclic spherical stress under different initial states. Irreversible and reversible components were identified from both volumetric and shear strains, and their variation patterns were analyzed. Shear strain is found to be generated by the material's anisotropy. The results indicate that the volume of the sample shrinks significantly under cyclic spherical stress, with irreversible volumetric strain increasing nonlinearly as the number of cycles increases. Irreversible shear strains can be categorized into two types based on their formation mechanisms. The first is when significant initial anisotropy leads to radial deformation greater than axial deformation under spherical stress, resulting in shear strain increasing in the negative direction. As consolidation stress increases, the initial anisotropy gradually diminishes. The second is when stress-induced anisotropy results in positive shear strain because consolidation deviatoric stress contributes to an increase in shear strain in the positive direction. As the stress ratio rises, the induced anisotropy is further enhanced. The axial reversible strain of the sample is minor, and the reversible components of volumetric and shear strains primarily arise from radial contraction and expansion. As the spherical stress increases, the sample volume shrinks (positive volumetric strain), whereas the initial anisotropy leads to negative shear strain, resulting in opposite signs. Finally, a method for predicting irreversible strain under cyclic spherical stress is established based on a memoryless geometric distribution.

Tetracycline (TC) is effectively used antibiotic in animal husbandry and healthcare, has damaged soil ecosystems due to its misuse and residues in the soil environment. Therefore, the main objective of this study was to abate TC in hyphosphere soil by inoculating soil with arbuscular mycorrhizal fungi (AMF) and to explore its potential mechanisms. The results showed that under TC stress, inoculation with AMF reduced the contents of soil organic carbon and total nitrogen, and increased the activities of beta-glucosidase and urease in hyphosphere soil. The relative abundance of bacterial genera such as Pseudomaricurvus in the hyphosphere soil increased significantly after AMF inoculation. In addition, four bacterial genera, Cellulosimicrobium, Roseibium, Citromicrobium, and Hephaestia, were uniquely present in AMF-inoculated soil, and the functional genes Unigene456231 and Unigene565663 were significantly enriched in the hyphosphere soil. This suggests that the reshaping of the bacterial community and the enrichment of functional genes in the hyphosphere soil led to changes in the bacterial community's functions, which promoted the gradual abatement of residual TC in the soil. It should be noted that this study was solely based on a single pot experiment, and its conclusions may have certain limitations in broader ecological application scenarios. Subsequent studies will further investigate the remediation effects under different environmental factors and field trials. This study provides new insights into the use of AMF as a biological agent for the remediation of TC-contaminated soils, offering new perspectives for promoting sustainable agricultural development.