Taurine (TAU) has recently been found to have an impactful role in regulating plant responses under abiotic stresses. This study presented the comparative effects of TAU seed priming and foliar spray application on chickpea plants exposed to hexavalent chromium. Taurine priming and foliar applications (1.6 and 2.4 mM) notably modulated morpho-physiological and biochemical responses of plants under Cr(VI) stress. Plants subjected to 25 mg kg-1 soil Cr in the form of potassium dichromate (K2Cr2O7) displayed a significant reduction in growth, chlorophyll, and uptake of essential nutrients (N, K, P, and Ca). Cr(VI) toxicity also resulted in a notable increase in osmolyte accumulation, lipid peroxidation, relative membrane permeability, ROS generation, antioxidant enzyme activities, antioxidant compounds, endogenous Cr levels, and aerial Cr translocation. Taurine abridged lipoxygenase activity to diminish lipid peroxidation owing to the overproduction of ROS initiated by a higher Cr content. The acquisition and assimilation of essential nutrients were augmented by the TAU-related decrease in leaf and root Cr levels. Consequently, TAU enhanced growth by mitigating oxidative damage, reducing Cr content in the aerial parts, and reinforcing the activities of antioxidant enzymes. Compared to foliar spray, TAU seed priming has demonstrated superior efficacy in mitigating Cr phytotoxicity in plants.
Correlations between the mechanical properties and surface scratch resistance of polylactic acid (PLA) are investigated via tensile and scratch tests on samples after degradation in soil for various times. The results show that the tensile yield strength of PLA is inversely proportional to the natural logarithm of the degradation time, and the scratch resistance and fracture toughness of PLA and the temperature rise near the indenter all increase and then decrease. The surface crystallinity of PLA also increases and then decreases, indicating that it and the scratch resistance are closely related. These findings provide useful information about how PLA behaves under degradation conditions. (c) 2025 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC) license (https://creativecommons.org/licenses/by-nc/4.0/).
Hydraulic conductivity plays a significant role in the evolution of liquefaction phenomena induced by seismic loading, influencing the pore water pressure buildup and dissipation, as well as the associated settlement during and after liquefaction. Experimental evidence indicates that hydraulic conductivity varies significantly during and after seismic excitation. However, most previous studies have focused on experimentally capturing soil hydraulic conductivity variations during the post-shaking phase, primarily based on the results at the stage of excess pore water pressure dissipation and consolidation of sand particles after liquefaction. This paper aims to quantify the variation of hydraulic conductivity during liquefaction, covering both the co-seismic and postshaking phases. Adopting a fully coupled solid-fluid formulation (u-p), a new back-analysis methodology is introduced which allows the direct estimation of the hydraulic conductivity of a soil deposit during liquefaction based on centrifuge data or field measurements. Data from eight well-documented free-field dynamic centrifuge tests are then analysed, revealing key characteristics of the variation of hydraulic conductivity during liquefaction. The results show that hydraulic conductivity increases rapidly at the onset of seismic shaking but gradually decreases despite high pore pressures persisting. The depicted trends are explained using the KozenyCarman equation, which highlights the combined effects of seismic shaking-induced agitation, liquefaction, and solidification on soil hydraulic conductivity during the co-seismic and post-shaking phases.
In performance-based design, it is crucial to understand deformation characteristics of geocell layers in soil under footing loads. To explore this, a series of laboratory loading tests were carried out to investigate the influence of varying parameters on the strain levels within the geocell layer in a sandy soil under axial strip footing loading. The results were analyzed in terms of maximum strain levels, strain variation along the geocell layer and the correlation between horizontal and vertical strains. In this study, the maximum observed strain levels for geocellreinforced strip footing systems reached 2.3 % for horizontal (tensile) strain and 1.4 % for vertical (compressive) strain. Furthermore, most strain levels were concentrated within a distance of 1.5 times the footing width from the axis of strip footing. In geocell-reinforced footing systems, the interaction between horizontal and vertical strains becomes a key factor, with the ratio of horizontal to vertical cell wall strains ranging approximately from 1 to 2.5. The outcomes of this study are expected to contribute to the practical applications of geocell-reinforced footing systems.
A realistic prediction of excess pore water pressure generation and the onset of liquefaction during earthquakes are crucial when performing effective seismic site response analysis. In the present research, the validation of two pore water pressure (PWP) models, namely energy-based GMP and strain-based VD models implemented in a one-dimensional site response analysis code, was conducted by comparing numerical predictions with highquality seismic centrifuge test measurements. A careful discussion on the selection of input soil parameters for numerical simulations was made with particular emphasis on the PWP model parameter calibration which was based on undrained stress-controlled/strain-controlled cyclic simple shear (CSS) tests carried out on the same sand used in the centrifuge test. The results of the study reveal that the energy-based model predicts at all depths peak pore water pressures and dissipation behaviour in a satisfactory way with respect to experimental measurements, whereas the strain-based model underestimates the PWP measurements at low depths. Further comparisons of the acceleration response spectra illustrate that both the strain- and energy-based models provide higher computed spectral accelerations near the ground surface compared with the recorded ones, whereas the agreement is reasonable at middle depth.
Open-ended pipe piles (OEPPs) are widely used in offshore foundations, yet accurately predicting their driving responses remains challenging due to soil plug complexities. Existing pile driving analysis models inadequately characterize the effects of soil plug, potentially leading to driving problems such as hammer refusal, pile running, and structural damage. This paper proposes an effective soil plug (ESP) model for OEPP driving analysis. The ESP model considers the effective range of soil plug, which exerts internal resistance that increases exponentially with depth while the beyond of effective range contributes only mass inertia. It also accounts for the relative slippage at the pile-soil plug interface. A differential iterative method is developed to solve the ESP model. Subsequently, investigations including the model validation and parameter analysis are conducted. Model validations against existing models and field measurements confirms the reliability of the ESP model. Parameters sensitivity analysis reveals the importance of soil plug length and distribution type of internal resistance on the pile dynamic responses. In addition, if soil plug slippage occurs, the displacement peak of soil plug increases with depth rather than one-dimensional wave attenuation. Furthermore, contrary to previous assumptions of continuous slippage, the soil plug experiences a discontinuous jump-sliding mode under long-duration impact loading. These findings provide theoretical basis for OEPP driving simulation and interpretations of high-strain dynamic test.
Large-diameter monopiles of offshore wind turbines are subjected to continuous multistage cyclic loads of different types (one-way or two-way) and loading amplitudes over time. The loading history is likely to affect the lateral response during the subsequent loading stage. This paper conducts a systematic study on the lateral response of monopiles with and without reinforcement in multilayer soil. Two groups of monotonic centrifuge tests of monopiles with and without reinforcement are carried out to compare and study the influence of reinforcement on the displacement, bending moment and earth pressure of monopile foundations. Local reinforcement in the shallow layer effectively improved the bearing capacity of the monopile foundation. The ultimate bearing capacity of monopile foundations in monotonic tests provides a load basis for cyclic tests. Four groups of continuous multistage cyclic centrifuge tests of monopiles with and without reinforcement with different cyclic modes and loading amplitudesare carried out to investigate the influence of loading history on the lateral cumulative displacement, unloading secant stiffness and bending moment. Empirical design recommendations for monopiles under continuous multistage cyclic loads with different cyclic modes and loading amplitudes are provided based on the results of the tests.
Drought and salt stress are two major abiotic factors significantly impacting crop growth and yield. Climate change leads to increasing drought and soil salinization issues, rising significant challenges to agricultural production. Amylases play a crucial role in enhancing the tolerance of crops to these stresses by regulating physiological and enzymatic activities. Previous study identified MeAMY1 and MeBAM3 as key genes involved in cassava starch metabolism under drought stress. To investigate their functions under drought and salt stress, MeAMY1 and MeBAM3 genes were cloned and over-expressed in Arabidopsis thaliana in the current study. Overexpression of MeAMY1 in Arabidopsis enhances amylase activities, promotes starch hydrolysis, releases soluble sugar and thus enhances osmotic balance in transgenic Arabidopsis. In the mean while, expression of BAM1 and SEX1 were depressed by MeAMY1 to maintain the protects cells closed under stress and preserved starch for adapting the stressful environments. Overexpression of the MeBAM3 in Arabidopsis can increase the expression levels of AMY3 and RVE1, promotes starch hydrolysis, releases soluble sugar from the chloroplasts to the cytoplasm and thus enhances osmoregulatory substance content, reducing stress-induced damage to antioxidant enzymes and cell membranes and improving stress tolerance. The principal component analysis further indicated that MeAMY1 and MeBAM3 overexpression lines responded similarly to drought stress, while MeBAM3 overexpression provided greater resilience to salt stress.
Subsea pipelines in Arctic environments face the risk of damage from ice gouging, where drifting ice keels scour the seabed. To ensure pipeline integrity, burial using methods like ploughs, mechanical trenchers, jetting, or hydraulic dredging is the conventional protection method. Each method has capabilities and limitations, resulting in different trench profiles and backfill characteristics. This study investigates the influence of these trenching methods and their associated trench geometries on pipeline response and seabed failure mechanisms during ice gouging events. Using advanced large deformation finite element (LDFE) analyses with a Coupled Eulerian-Lagrangian (CEL) algorithm, the complex soil behavior, including strain-rate dependency and strainsoftening effects, is modeled. The simulations explicitly incorporate the pipeline, enabling a detailed analysis of its behavior under ice gouging loads. The simulations analyze subgouge soil displacement, pipeline displacement, strains, and ovalization. The findings reveal a direct correlation between increasing trench wall angle and width and the intensification of the backfill removal mechanism. Trench geometry significantly influences the pipeline's horizontal and vertical displacement, while axial displacement and ovalization are less affected. This study emphasizes the crucial role of trenching technique selection and trench shape design in mitigating the risks of ice gouging, highlighting the value of numerical modeling in optimizing pipeline protection strategies in these challenging environments.
Large-span corrugated steel utility tunnels are widely used owing to their large spatial spans and excellent mechanical properties. However, under seismic forces, they may experience significant deformation, making repair challenging and posing a serious threat to personal safety. To study the seismic performance of corrugated steel utility tunnels, an equivalent orthotropic plate was introduced, and a simplified three-dimensional refined finite element model was proposed and established. Considering the site conditions of the structure, the structural parameters, and different seismic input conditions, a detailed analysis was conducted using the endurance time analysis method. The results indicated that the simplified model agreed well with the experimental results. The seismic input conditions significantly affected the relative deformation of the structure. Under the action of P waves (compression waves) and P + SV waves (compression and shear waves), the deformation of the upper part of the structure was relatively uniform, whereas under the action of SV waves (shear waves), the deformation of the crown was more evident. The greater the burial depth of the structure, the stronger the soil-structure interaction, and the smaller the increase in relative deformation. In soft soil, the structure was more likely to be damaged and should be carefully observed. Additionally, increasing the corrugation profile of the steel plates during the design process was highly effective in enhancing the overall stiffness of the structure. Based on the above calculation results, the relative deformation rate was proposed as a quantitative index of the seismic performance of the structure, and corresponding values were recommended.