To study the failure mechanism of high ductile coagulation (HDC) under sulfate attack in cold saline soil area, cement-based cementing material (cement: fly ash: sand: water reducing agent: water = 1:1:0.72:0.03:0.58) and 2 % polyvinyl alcohol fiber (PVA) were used to prepare HDC sample, to increase the density and ductility of concrete. a 540-day sulfate-long-term immersion test was performed on HDC specimens under two low-temperature curing environments and different sulfate solution concentrations (5 %, 10 %). Using a combination of macro and microscopic methods, according to the principle of energy dissipation, To study the relationship between the evolution of energy (total damage energy U, dissipated energy Uds, elastic strain energy Ues) and the deterioration of strength and the change of pore structure during the compression process of HDC. According to the characteristics of stress-strain curves during HDC compression, the damage evolution characteristics of characteristic stress points during HDC compression are summarized, establish energy storage indicators Kel to evaluate the degree of internal damage of HDC. The results show that during the compression damage process of HDC after long-term soaking in sulfate solution under low temperature environment, Uds and Ues of HDC at characteristic stress points both increase first and then decrease, Kel are reduced first and then increased. The development trend of elastic strain energy and dissipative energy of HDC in 10 % sulfate solution is more drastic than that in 5 % sulfate solution. Compared with the other three groups, the D group energy storage level rises and falls more violently, and the HDC has a smaller ability to resist damage under this condition. Through the study of the correlation between macro and micro changes of HDC in cold saline soil areas and energy evolution, to provide a reference for the stable operation of highly ductile concrete in cold saline soil areas.

Anthropogenic activities enhance the concentration of trace elements in environment like highly carcinogenic Cadmium (Cd), which adversely affect the plant growth and development. They deliberately accumulate defense compounds e.g., flavonoids, terpenoids, and alkaloids to ensure resilience in such adverse conditions. Current study explores the adaptive evolution, structural complexity, and functional roles of Flavin Adenine Dinucleotide (FAD)-linked oxidase genes in widespread leading cash crop cotton. As a non-edible, hyperaccumulator halophyte crop, cotton is an excellent candidate for phytoremediation of Cd-polluted soils by manipulating stress resistant genetic material. They utilize FAD as a cofactor to drive oxidative reactions, including benzylisoquinoline alkaloid biosynthesis, which plays a critical role in cellular signaling pathways, stress responses and metabolic processes. A total of 387 FADs retrieved from four cotton species were distributed into seven families and twelve subfamilies. They underwent large scale expansion under intense purifying selection with lineagespecific gene loss and retention, reflecting their ongoing evolution for functional advancements to adopt altering environment. High throughput transcriptomic, functional enrichment and qRT-PCR validation revealed their multifaceted roles in growth, development and stress responses. Overexpression of GhBBE59 (BBE7) in Arabidopsis enhanced Cd tolerance by 25 % marked by a 20% reduction in malondiadehyde (MDA) and 25 % higher superoxide dismutase (SOD) activity compared to wild type plants. While its knockdown in cotton, reduced Proline accumulation by 60 % and increased electrolyte leakage by 2 fold, rendering plants hypersensitity to Cd stress. Transcriptomic and biochemical analyses demonstrated that BBE7 modulates redox homeostasis via 25% higher glutathione accumulation and hormonal crosstalk, mitigating oxidative damage. Functional analyses further revealed the pivotal role of BBE7 in regulation of oxidative stress, antioxidant production, epigenetic modifications and proline accumulation, thereby enhancing stress resilience. These findings hold substantial promise for reducing cadmium accumulation in soils, thereby mitigating its entry into the food chain and associated health risks. The implications of current study extend beyond fundamental research, addressing real-world challenges associated with environmental stresses and sustainable agriculture practices by enabling safer cultivation in polluted environments.

During the landfilling and resource utilization of solidified soil, it is inevitable that the material will be influenced by the surrounding water environment. Processes such as soaking and infiltration of both clean water and contaminated liquids can have an impact. This paper investigates the strength and structural stability of soil contaminated with a high concentration of lead or copper that has been solidified with red mud-carbide slag-phosphogypsum (RCP-Pb or RCP-Cu, respectively) in strongly acidic water, weakly acidic water, and pure water, as well as in two different modes of soaking and infiltration. The unconfined compressive strength, apparent and microscopic morphology, mineral composition, and functional groups of solidified soil before and after the action of different water solutions were compared, and the water and acid resistance of solidified soil was comprehensively analyzed. The results indicate that under the influence of a strongly acidic water environment, the strength of RCP-Pb and RCP-Cu can decrease by up to 26.4% and 18.5%, respectively, compared to the standard solidified specimens. Conversely, in a weakly acidic environment, the strength of the specimens can increase by a maximum of 21.1% and 32.8%, respectively. Under the two different water environment modes of action, RCP-Pb exhibits a greater increase in strength (39.8%) under soaking conditions, while RCP-Cu shows a greater increase (44.4%) under water infiltration. Based on the microscopic images, the pore counts in specimens in weakly acidic and pure water environments are greater than those in standard solidified specimens, while the porosity is less than that in standard solidified specimens. The surface of the particles exhibited increased roughness. A noticeable finding is that, under the infiltration of a strongly acidic water environment, the porosity of RCP-Pb increases to 20.22%, and the pore counts of RCP-Cu rise to 534. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analyses revealed that as the acidity of the water environment increased, the CaCO3 content significantly decreased. However, hydration products such as calcium silicate hydrate (C-S-H), calcium aluminate hydrate (C-A-H), calcium aluminosilicate hydrate (C-A-S-H), and ettringite (AFt) did not show significant differences. Consequently, the specimens maintained a stable strength and structure even under such a water environment.

Due to Paleo-clay's unique properties and widespread distribution throughout China, it is essential in geotechnical engineering. Rainfall frequently causes the deformation of Paleo-clay slopes, making slope instability prediction crucial for disaster prevention. This study explored Paleo-clay's strength degradation and slope stability under soaking and wet-dry cycles. Using Mohr-Coulomb failure envelopes from experiments, curve fitting was used to find the patterns of Paleo-clay strength degradation. Finite element simulations and the strength discounting method were used to analyze the stability and deformation of Paleo-clay slopes. The results indicate that wet-dry cycles impact them more than soaking. Paleo-clay's cohesion decreases exponentially as the number of wet-dry cycles and soaking times rise, but the internal friction angle changes very little. After 10 wet-dry cycles and 24 days of soaking, iron-bearing clay's cohesion decreased to 17% and 44% and reticular clay's to 32% and 48%. Based on the study area characteristics, three slope types were constructed. Their stability exhibited exponential decay. Under soaking, stability remained above 1.4; under wet-dry cycles, type I and II stability fell below 1.0, leading to deformation and failure. All types showed traction landslides with sliding zones transitioning from deep to shallow. Practical engineering should focus on the shallow failures of Paleo-clay slopes.

Climate change and rapid socioeconomic development have exacerbated the damage caused by hydrological droughts. To ensure effective drought defense and infrastructure development, it is essential to investigate variations in hydrological droughts. The primary objective of this study is to reconstruct the natural streamflow by using Soil and Water Assessment Tool (SWAT) hydrological modeling. The hydrological drought at different time scales (1, 3, 6, and 12 months) were measured using the streamflow drought index (SDI). The statistical parameters, including Nash-Sutcliffe Efficiency and the Coefficient of Determination, which yielded values of 0.84 and 0.82 during the calibration period and 0.78 and 0.76 during the validation period, respectively, showed a satisfactory SWAT model performance. Additionally, the Pettit test was used to identify a change point in streamflow within the 1991-2015 timeframe, leading to the division of the study period into two distinct phases: an undisturbed period (1991-1998) and a disturbed period (1999-2015). The SDI index-based analysis revealed 9.39% moderate drought and 3.13% severe drought during the undisturbed period, while 11.76% moderate drought and 7.35% severe drought may happen due to the human influences that occurred in the disturbed period. These findings enhance the understanding of the hydrological drought variations in the Soan River basin for optimizing the water resources management system and effectively preventing and mitigating drought-related damages.

This paper presents experimental studies on a compacted expansive soil, from Nanyang, China for investigating the at-rest lateral earth pressure sigma(L) of expansive soils. The key studies include (i) relationships between the aL and the vertical stress sigma(V) during soaking and consolidation, (ii) the influences of initial dry density p(d0) and moisture content w(0) on the vertical and lateral swelling pressures at no swelling strain (i.e. sigma(V0) and sigma(L0)), and (iii) evolution of the sigma(L) during five long-term wetting-drying cycles. Experimental results demonstrated that the post-soaking sigma(L)-sigma(V) relationships are piecewise linear and their slopes in the passive state (sigma(L) > sigma(V)) and active state (sigma(L) < sigma(V)) are similar to that of the consolidation sigma(L)-sigma(V) relationships in the normal- and over-consolidated states, respectively. The soaking sigma(L)-sigma(V) relationships converge to the consolidation sigma(L)-sigma(V) relationships at a threshold aV where the interparticle swelling is restrained. The sigma(L0) and sigma(V0) increase monotonically with p(d0); however, they show increasingthen-decreasing trends with the w(0). The extent of compaction-induced swelling anisotropy, which is evaluated by sigma(L0)/sigma(V0), reduces with an increase in the compaction energy and molding water content. The sigma(L) reduces over moisture cycles and the stress relaxation in the sigma(L) during soaking is observed. An approach was developed to predict the at-rest soaking sigma(L)-sigma(V) relationships, which requires conventional consolidation and shear strength properties and one measurement of the sigma(L)-sigma(V) relationships during soaking. The proposed approach was validated using the results of three different expansive soils available in the literature. (c) 2024 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

In salt-rich soft soil regions, as a backfill material, foamed lightweight soil (FLS) is often subjected to long-term chemical erosion of groundwater, which would lead to a continuous degradation of strength properties, and ultimately causes a risk to the long-term safety of infrastructures. Combining sulfate chemical soaking test and dry-wet cycle test, this paper investigates the durability changes of FLS under different densities of FLS, sulfate concentrations, and cation types of sulfate. The results indicate that the dynamic strength degradation of FLS under dry-wet cycles is much greater than that under sulfate soaking. When other influencing factors remain unchanged, the corrosiveness of Na2SO4 solution is greater than that of MgSO4 solution. Moreover, this paper establishes a dynamic strength degradation prediction model for FLS based on the experimental results, which can scientifically guide the durability changes of FLS under different influencing factors.

Biomass burning (BB) is an important source of primary organic aerosols (POA). These POA contain a significant fraction of semivolatile organic compounds, and can release them into the gas phase during the dilution process in transport. Such evaporated compounds were termed secondarily evaporated BB organic gases (SBB-OGs) to distinguish them from the more studied primary emissions. SBB-OGs contribute to the formation of secondary organic aerosols (SOA) through reactions with atmospheric oxidants, and thus may influence human health and the Earth's radiation budget. In this study, tar materials collected from wood pyrolysis were taken as proxies for POA from smoldering-phase BB and were used to release SBB-OGs constantly in the lab. OH-initiated oxidation of the SBB-OGs in the absence of NOx was investigated using an oxidation flow reactor, and the chemical, optical, and toxicological properties of SOA were comprehensively characterized. Carbonyl compounds were the most abundant species in identified SOA species. Human lung epithelial cells exposed to an environmentally relevant dose of the most aged SOA did not exhibit detectable cell mortality. The oxidative potential of SOA was characterized with the dithiothreitol (DTT) assay, and its DTT consumption rate was 15.5 +/- 0.5 pmol min 1 mu g(-1). The SOA present comparable light scattering to BB-POA, but have lower light absorption with imaginary refractive index less than 0.01 within the wavelength range of 360-600 nm. Calculations based on Mie theory show that pure airborne SOA with atmospherically relevant sizes of 50-400 nm have a cooling effect; when acting as the coating materials, these SOA can counteract the warming effect brought by airborne black carbon aerosol.

This study applies the nested-grid version of Goddard Earth Observing System (GEOS) chemical transport model (GEOS-Chem) to examine future changes (2000-2050) in SOA concentration and associated direct radiative forcing (DRF) over China under the Representative Concentration Pathways (RCPs). The projected changes in SOA concentrations over 2010-2050 generally follow future changes in emissions of toluene and xylene. On an annual mean basis, the largest increase in SOA over eastern China is simulated to be 25.1% in 2020 under RCP2.6, 20.4% in 2020 under RCP4.5, 56.3% in 2050 under RCP6.0, and 44.6% in 2030 under RCP8.5. The role of SOA in PM2.5 increases with each decade in 2010-2050 under RCP2.6, RCP4.5, and RCPS.5, with a maximum ratio of concentration of SOA to that of PM2.5 of 16.3% in 2050 under RCP4.5 as averaged over eastern China (20 degrees-45 degrees N, 100 degrees-125 degrees E). Concentrations of SOA are projected to be able to exceed those of sulfate, ammonium, and black carbon (BC) in the future. The future changes in SOA levels over eastern China are simulated to lead to domain-averaged (20 degrees-45 degrees N, 100 degrees-125 degrees E) DRI's of +0.19 W m(-2), +0.12 W m(-2), -0.28 W m(-2), and -0.17 W m(-2) in 2050 relative to 2000 under RCP2.6, RCP4.5, RCP6.0, and RCP8.5, respectively. Model results indicate that future changes in SOA owing to future changes in anthropogenic precursor emissions are important for future air quality planning and climate mitigation measures. (C) 2018 Elsevier B.V. All rights reserved.

Secondary organic aerosol (SOA) nearly always exists as an internal mixture, and the distribution of this mixture depends on the formation mechanism of SOA. A model is developed to examine the influence of using an internal mixing state based on the mechanism of formation and to estimate the radiative forcing of SOA in the future. For the present day, 66% of SOA is internally mixed with sulfate, while 34% is internally mixed with primary soot. Compared with using an external mixture, the direct effect of SOA is decreased due to the decrease in total aerosol surface area and the increase of absorption efficiency. Aerosol number concentrations are sharply reduced, and this is responsible for a large decrease in the cloud albedo effect. Internal mixing decreases the radiative effect of SOA by a factor of >4 compared with treating SOA as an external mixture. The future SOA burden increases by 24% due to CO2 increases and climate change, leading to a total (direct plus cloud albedo) radiative forcing of -0.05 W m(-2). When the combined effects of changes in climate, anthropogenic emissions, and land use are included, the SOA forcing is -0.07 W m(-2), even though the SOA burden only increases by 6.8%. This is caused by the substantial increase of SOA associated with sulfate in the Aitken mode. The Aitken mode increase contributes to the enhancement of first indirect radiative forcing, which dominates the total radiative forcing.