The study of the damage effects resulting from the explosions of cylindrical charges holds significant importance in both military and civilian fields. In contrast to spherical charges, the explosive characteristics of the cylindrical charge exhibited spatial irregularities. To comprehensively quantify the influences of borehole diameter and buried depth on the damage effects, including the crater size and stress wave, experimental and numerical investigations on explosions induced by cylindrical charge are carried out in this paper. Firstly, a set of tests is conducted to provide fundamental data. Then, based on the meshfree method of Smoothed Particle Galerkin (SPG) and the K&C model, the variations in crater dimensions and the peak stress are fully simulated with a range of borehole diameters and buried depths. Finally, the influence of borehole and buried depth on the coupling factor is discussed. Both the buried depth and the borehole diameter impact the utilization of blast energy enormously. Furthermore, materials with distinct impedance values exert an influence on the distribution of the stress wave. Following the dimensional analysis, several empirical formulae expressing the crater size and peak stress are established, all of which can predict explosion damage rapidly and accurately.

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.

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.

Plant-parasitic nematodes pose a silent yet devastating threat to global agriculture, causing significant yield losses and economic damage. Traditional detection methods such as soil sampling, microscopy, and molecular diagnostics are slow, labor-intensive, and often ineffective in early-stage infestations. Nano biosensors: cuttingedge analytical tools that leverage nanomaterials like carbon nanotubes, graphene, and quantum dots to detect nematode-specific biochemical markers such as volatile organic compounds (VOCs) and oesophageal gland secretions, with unprecedented speed and accuracy. The real breakthrough lies in the fusion of artificial intelligence (AI) and nano-biosensor technology, forging a new frontier in precision agriculture. By integrating AI's powerful data analysis, pattern recognition, and predictive capabilities with the extraordinary sensitivity and specificity of nano-biosensors, it becomes possible to detect biomolecular changes in real-time, even at the earliest stages of disease progression. AI-driven nano biosensors can analyze real-time data, enhance detection precision, and provide actionable insights for farmers, enabling proactive and targeted pest management. This synergy revolutionizes nematode monitoring, paving the way for smarter, more sustainable agricultural practices. This review explores the transformative potential of AI-powered nano-biosensors in advancing precision agriculture. By integrating these technologies with smart farming systems, we move closer to real-time, costeffective, and field-deployable solutions, ushering in a new era of high-tech, eco-friendly crop protection.

Cadmium (Cd) accumulation in Solanum nigrum L. is known to occur mainly in cell walls and vesicles. However, limited research has been conducted on the toxic effects of Cd specifically targeting mitochondria in S. nigrum leaves. This study aims to delineate the impact of Cd accumulation on mitochondrial structure and function in S. nigrum leaves, thereby providing a theoretical foundation for enhancing its application in phytoremediation of Cd-polluted soils. The results showed that the Cd content in mitochondria would gradually reach saturation with the increase of Cd treatment concentration. However, the accumulation of Cd led to osmotic pressure imbalance and morphological changes within mitochondria, which in turn caused a series of impairments in mitochondrial function. Cd severely damaged the energy metabolism function of mitochondria, especially under 200 mu M CdCl2 stress, the mitochondrial ATP content decreased by 90.65 % and the activity of H+-ATPase decreased by 80.65 %. Furthermore, reactive oxygen species (ROS) in mitochondria accumulated mainly in the form of H2O2. Compared with the non-Cd control group, the H2O2 content in the Cd-treated groups (50, 100, and 200 mu M CdCl2) increased by 61.62 %, 186.69 %, and 405.81 %, respectively. The inhibition of cellular respiration by Cd and the sharp increase in ROS exacerbated the oxidative damage in mitochondria. Interestingly, the activities of mitochondrial peroxidase (POD) and dehydroascorbate reductase (DHAR) exhibit remarkable tolerance under Cd stress. Based on these results, we believe that Cd can cause dysfunction and oxidative damage to the mitochondria of S. nigrum leaves.

Pipe piles, such as offshore monopiles, may suffer from considerable damage at the pile tip during installation because of contact with an obstacle such as a boulder or a stiff soil layer but also because of amplification of a pre-deformation or pre-dent. This damage is often referred to as pile tip buckling initiation in the former situation and extrusion buckling in the latter. This paper reports on a series of model tests carried out to verify the numerical model and understand pile tip buckling during impact driving in saturated, dense sand. The test program includes three different scenarios: tests with an initial dent at the pile tip, tests with a fixed rigid body and tests with free-moving rigid bodies (boulders) placed at a certain depth in the sand. The results show that the soil stress level strongly influences pile tip buckling. At high soil stress levels, the penetration rate of the pile decreases progressively. Notably, the wall thickness of the pile has a significant effect on the penetration curve in the case of pre-dented piles. The tests with boulders at low soil stress levels show that the buckling behavior is strongly influenced by the shape of the boulder, by the point of initial contact and by the movement of the boulder. Only small deformations can be observed at the pile tip due to the contact with a spherical steel boulder, whereas the test with the imperfectly shaped stone boulder caused considerable damage to the pile under otherwise equal test conditions.

Satellite-derived land surface temperature (LST) is a directional variable and has significant angular anisotropy. This characteristic contributes to enhance the differences among different satellite-derived LST products, and therefore increases the challenge of using multi-sensor and multi-decadal data to provide a long-term and angleconsistent LST climate data record. The kernel-driven model can balance the interpretability and operability well, so that it is suitable for angular normalization of LST products. The calibration of the kernel-driven model depends on multi-angle data which is difficult to obtain due to the spatial-temporal heterogeneity of LST. In this study, a novel LST angular normalization method based on the kernel-driven model was proposed to correct the angular effect of satellite-derived LST product by constructing multi-angle LST dataset from one geostationary satellite (GOES-R/ABI) and four polar-orbiting satellites (Terra/MODIS, Aqua/MODIS, Metop/AVHRR, and SNPP/VIIRS). The dataset gathered more abundant angle information, i.e., LSTs from three different observation geometries for the same pixel. The kernel-driven model was calibrated using the multi-angle LST dataset in the Continental United States (CONUS) during the year 2020. The discrepancies of the root mean square difference between LST before and after angular normalization range from 0.14 K to 1.10 K over nine land cover types in the four seasons. Similar results are obtained when the calibrated kernel-driven model was further expanded to other years and areas (i.e., the CONUS in 2021 and East Asia in 2020). The LST angular normalization method was applied to correct the angular effect of MODIS LST product. The results indicate that there is a strong correlation between the spatial distribution of LST differences (LST before and after angular normalization) and view zenith angle (VZA). MODIS LSTs before and after angular normalization were compared with Landsat 8 LST and Sentinel-3 A LST in near-nadir viewing for January, April, July, and October 2020. The angular normalization reduced the root mean square error (RMSE) between MODIS LST and Landsat 8 LST by 0.94-2.06 K in different months and by 0.13-2.61 K over various land cover types. For Sentinel-3 A, the RMSE decreased by 0.30-0.64 K in different months. The accuracies of MODIS LST before and after angular normalization were further validated using in situ measurements at the six SURFRAD sites. There are large discrepancies between the RMSE of MODIS LST before and after angular normalization versus in situ LST for VZA >= 45 degrees. The largest discrepancy is up to approximately 1.3 K at the GWN site. The LST angular normalization method has the potential to provide an angle-consistent LST climate data record.

A novel approach to enhance wellbore stability was put forth, based on the wellbore rock properties and instability mechanism of the hydrate reservoir, given the issue of wellbore instability when using water-based drilling fluids (WBDFs) in drilling operations, in weakly cemented muddy fine silt reservoirs of natural gas hydrates in the South China Sea. Three main strategies were used to increase the stability of reservoirs: enhancing the underwater connection between sandstone particles and clay minerals, preventing clay hydration from spreading and expanding, and strengthening the stability of hydration skeleton structure. An appropriate drilling fluid system was built with soil phase containing wellbore stabilizer. Sulfonic acid groups and electrostatic interaction were introduced based on the characteristics of underwater adhesion of mussels. Through the process of free radical polymerization, a zwitterionic polymer containing catechol groups named DAAT was prepared for application in natural gas hydrate reservoir drilling. DAAT is composed of tannic acid (TA), dimethyl diallyl chloride ammonium chloride (DMDAAC), 2-acrylamide-2-methylpropanesulfonic acid (AMPS) and acrylamide (AM). Experimental results from mechanical property testing reveal an adhesion force of up to 4206 nN between SiO2 and 5 wt % DAAT, demonstrating its ability to bind quartz sand particles effectively. The compressive strength and cohesion of the cores treated with DAAT increased by 58.33 wt % and 53.26 wt %, respectively, at -10 degrees C, compared with pure ice particle cores. This demonstrates DAAT can significantly enhance the compressive strength and cohesion of the core. Furthermore, the adhesion force between DAAT and hydrate particles reaches up to 344.4 mN/m, significantly improving the structural stability between hydrate particles. It demonstrates excellent adhesive properties to hydrate particles. In addition to adsorbing clay minerals, rocks, and hydrate particles, DAAT also forms hydrogen bonds with argillaceous fine silt particles with its low temperature cohesiveness characteristic. As a result, it improves the cohesion between core particles, and enhances the adhesion between hydrates and rocks, thereby enhancing the stability of hydrate reservoirs. In summary, DAAT is characterized by a simple preparation process, cost-effectiveness, and environmental friendliness. It is an innovative and practical material for enhancing wellbore stability in WBDFs for natural gas hydrate exploration in the South China Sea.

With increasing water depth, marine drilling conductors exhibit higher slenderness ratios, significantly reducing their resistance to environmental loads in Arctic waters. These conductors, when subjected to combined wind, current, and ice loads, may experience substantial horizontal displacements and bending moments, potentially compromising offshore operational safety and wellhead stability. Additionally, soil disturbance near the mudline diminishes the conductor's bearing capacity, potentially rendering it inadequate for wellhead support and increasing operational risks. This study introduces a static analysis model based on plastic hinge theory to evaluate conductor survivability. The conductor analysis divides the structure into three segments: above waterline, submerged, and embedded below mudline. An idealized elastic-plastic p-y curve model characterizes soil behavior beneath the mudline, while the finite difference method (FDM) analyzes the conductor's mechanical response under complex pile-head boundary conditions. Numerical simulations using ABAQUS validate the plastic hinge approach against conventional methods, confirming its accuracy in predicting structural performance. These results provide valuable insights for optimizing installation depths and bearing capacity designs of marine drilling conductors in ice-prone regions.

Compared with the water-base drilling fluid, oil-based drilling fluid has always been one of the important technical guarantees in high temperature deep well, high-inclination directional well and all kinds of complex seismic exploration. With 5#white oil selected and taken as continuous phase, emulsifying agent, organic soil, tackifier, fluid loss agent, lime, other treatment agents and dosages are optimized and the optimal formula of oil-base drilling fluid is determined. This new type environmentally-friendly oil-base drilling fluid possesses good rheological properties, suspension capability, high temperature stability, stronger anti-pollution ability and common emulsion-breaking voltage of more than 2000 V. During the field application, this fluid possesses regular borehole diameter, good lubricity, stable borehole, simple preparation process, easy site maintenance and good reservoir protection features. Furthermore, it can solve complex formation, water expansion of clay shale, poor lubrication & drag reduction effect, poor reservoir protection effect and other technically-difficult problems.