Response characteristics of shale permeability to cyclic loading under different gas pressures.

The permeability evolution characteristics of low-permeability shale layers directly influence shale gas development. However, the evolution law of shale reservoir permeability in complex environments remains unclear. Therefore, understanding the permeability characteristics of shale layers is of great significance.

Single-Sensor Impact Source Localization Method for Anisotropic Glass Fiber Composite Wind Turbine Blades.

The wind turbine blade is subject to multi-source impacts, such as bird strikes, lightning strikes, and hail, throughout its extended service. Accurate localization of those impact sources is a key technical link in structural health monitoring of the wind turbine blade. In this paper, a single-sensor impact source localization method is proposed.

Optimization Design of the Two-Stage Reduction Micro-Drive Mechanism Based on Particle Swarm Algorithm.

Achieving high-precision positioning operations in a small space was of great significance in aerospace, biomedical, and other fields. In order to obtain smaller displacements with higher accuracy, this paper focused on the design, optimization, and performance analysis of a two-stage reduction micro-drive mechanism. Using the principle of lever and the principle of balanced additional force, a two-stage reduction micro-motion mechanism without parasitic motion and non-motion directional force was designed, and the structure optimization of the mechanism was completed by employing the particle swarm algorithm.

Dynamic Error Modeling and Predictive Compensation for Direct-Drive Turntables Based on CEEMDAN-TPE-LightGBM-APC Algorithm.

The direct-drive turntable serves as the core actuator in high-precision macro-micro drive systems, where its positioning accuracy fundamentally determines overall system performance. Accurate error prediction and compensation technology represent a critical prerequisite for achieving continuous error compensation and predictive control in direct-drive turntables, making research on positioning error modeling, prediction, and compensation of vital importance. This study presents a dynamic continuous error compensation model for direct-drive turntables, based on an analysis of positioning error mechanisms and the implementation of a "decomposition-modeling-integration-correction" strategy, which features high flexibility, adaptability, and online prediction-correction capabilities.

The Research and Application of Ejectors in Managing Low Oxygen Levels in Workface Corners.

During routine retreat mining operations, the corners of mine workfaces are susceptible to low oxygen phenomena, which can pose breathing challenges and other health risks to workers. To address this issue, a prevention and control technique based on the principle of ejectors was developed and implemented. The study analyzed the working mechanism of ejectors in mitigating low oxygen conditions and integrated this technology into field applications.

An artificial intelligence modeling framework based on microbial community structure prediction enhances the pollutant removal efficiency of the algae-bacteria granular sludge system.

Algae-bacteria granular sludge (ABGS) technology is a new energy-saving and low-carbon water treatment technology based on the algae-bacteria symbiotic system. However, due to its complex internal microbial system, the regulation mechanism of ABGS is unclear. To address this issue, the present study constructed a two-stage optimal control model for the ABGS system, which includes prediction of microbial community structure and planning of pollutant removal efficiency.

Binocular vs. monocular 3D cues in multiple object tracking: expertise differences between soccer players and non-athletes.

Classical two-dimensional multiple object tracking (2D-MOT) measures the cognitive ability to track multiple moving elements in real-life-like scenarios. Stereo-three-dimensional MOT (S-3D-MOT), a more ecologically valid form of 2D-MOT, shows better tracking performance in soccer players. Its unique feature is the additional binocular and monocular 3D cues compared to 2D-MOT, but their individual contributions to MOT performance are unclear.

Recent Progress of Stereolithography-Based Additive Manufactured Electrodes for Supercapacitors: Materials, Structures, Performance, and Perspectives.

Stereolithography-based additive manufacturing techniques, leveraging their superior capability for high-precision fabrication of 3D structures with well-defined periodicity and complex geometries, have unlocked unprecedented opportunities in constructing architecturally engineered 3D electrodes for advanced supercapacitors. Over the past few years, a series of groundbreaking achievements in stereolithography-based additive manufactured 3D structural electrodes have been successively reported, fostering a comprehensive understanding of recent advances and a strategic re-evaluation of future research direction. In this review, the latest representative progress in stereolithography-based additive manufactured electrodes for supercapacitors, covering ceramic-based electrodes, carbon-based electrodes, resin-based electrodes, and carbon-ceramic-based electrodes, is first summarized.

Study on the effect of subway construction on adjacent architectural heritages and protection measures.

The construction of the subway threatens the safety of adjacent architectural heritages. This study investigates the effect of subway foundation pit excavation and train-induced vibrations on adjacent architectural heritage through a case study of the City Square Station in Shaoxing. A three-dimensional numerical model was established by MIDAS GTS.

Species richness prediction and priority conservation planning for rare Michelia species in China.

Numerous species are at risk of extinction due to habitat degradation caused by human activity and global warming. This study is based on ecological niche modeling (MaxEnt) and systematic conservation planning modeling (Marxan) to predict the distribution and conservation of rare Michelia species. The findings indicate that rare Michelia species are found in southern Yunnan Province, which exhibits the highest concentration.

Quantitative sources identification of gas emissions in mined-out area of coal seams in the Huanglong coalfield of the Ordos Basin, China.

This study integrates different geochemical analyses (chemical compositions, carbon isotopes) and a physical mixing model to quantitatively identify gas sources and migration mechanisms in the Nanchuan No.2 coal mine. Results reveal distinct isotopic signatures: gases from mine-out area exhibit intermediate δC values (- 55.

Liquid Metal-Based Capacitive Strain Sensor with Self-Shielding and Low-Hysteresis.

Soft capacitive strain sensors with soft conductive electrodes are advantageous for their ability to decouple resistance from the flexible electrodes, offering excellent repeatability, low hysteresis, low energy consumption, and good temperature stability. However, existing soft capacitive strain sensors utilize intrinsically stiff conductors as soft electrodes, limiting the sensitivity, repeatability, and hysteresis. To address these issues, this work proposes a soft capacitive strain sensor based on liquid metal.

High-Performance Textile Piezoresistive Sensor: Graded Contact Hollow Architecture with Synergistic Flame Retardancy, Superhydrophobicity, and Thermal Insulation.

To address the challenges of complex fabrication, low sensitivity under high pressure, and poor environmental tolerance in conventional textile pressure sensors, this study proposes an economical and effective graded contact hollow architecture sensor (CCHD) design. Through a multistage contact mechanism combining hollow cavities with gradient conductive carbon layers, the sensor's maximum sensitivity response range extends to 5 times (0-13.9 kPa, with a sensitivity of 4.

Toward Superior Electrochemical Capacitance with Hierarchically Nanostructured Polypyrrole/MXene Hybrid Hydrogel Modified by Lignosulfonate.

Although the TiC MXene has demonstrated exceptional promise for supercapacitor applications, its practical implementation is limited by its inherent tendency of undergoing restacking and oxidation. Herein, we propose a facile self-assembly strategy of in situ polymerization to construct lignosulfonate (LS)-modified polypyrrole (PPy)/MXene hybrid hydrogels with a hierarchical porous structure. The formed PPy nanoparticles and coating layer effectively prevent MXene restacking and oxidation, while enhancing electrical conductivity and electrochemical activity.

Experimental study of gas flow and coal deformation at different levels of axial/radial stress ratio.

CH flow dynamics in coal, governed primarily by adsorption, desorption, and seepage processes, are critical for determining gas extraction efficiency. Coal seam deformation under varying stress conditions further significantly impacts CH flow. Utilizing a self-developed coal solid-gas coupling test apparatus, this study conducted simultaneous measurements of CH flow and coal deformation under different axial-to-radial stress ratios.

High-intensity exercise training mitigates post-exercise orthostatic hypotension in men.

Whether high-intensity exercise training can effectively mitigate orthostatic-induced post-exercise hypotension (PEH) has not been satisfactory resolved to date. We therefore examined whether 2 weeks of high-intensity exercise training can effectively mitigate the orthostatic-induced PEH by conducting comparisons pre- and post-training at the same absolute and relative workloads. Eleven healthy men underwent 2 weeks of high-intensity exercise training within the severe intensity domain (i.

Design, modeling, and experimental evaluation of a piezoelectric actuator based on four-stage magnifying mechanism.

This study designs a novel piezoelectric actuator (PA) and models and experimentally evaluates it, which improves the output stroke and driving efficiency. A four-stage magnifying mechanism with an ingenious structure is utilized to magnify the displacements of the piezoelectric material stacks. Rhombic, lever, triangular, and lever mechanisms form the four-stage magnifying mechanism.

The propagation characteristics of acoustic surface waves and the applications of power ultrasound based on AlN/GaN piezoelectric thin films.

To address the growing need for high-frequency tunable surface acoustic wave (SAW) devices in power ultrasound applications, this study uses finite element method (FEM) for designing and simulation of an AlN/GaN composite heterogeneous piezoelectric thin film structure fabricated on a sapphire substrate. The configuration employs a double piezoelectric layer approach to significantly improve electromechanical conversion efficiency, achieving an electromechanical coupling coefficient of 0.42%.

Modification of Ni/Sepiolite with Ultrathin MnO Nanosheets Driving Superior CO Methanation: Synergistic Potentiation of Surface Alkalinity and Oxygen Vacancies.

Modification of monometallic Ni-based catalysts by transition metals may open a new window to compensate for their poor low-temperature activity and high-temperature deactivation in the CO methanation reaction. Here, some transition metals were incorporated into Ni/sepiolite (Sep) by a facile one-step coimpregnation process, where the ultrathin (1.5-2.

Principal stress rotation effect and multi-factor coupling support optimization in roadways of inclined coal seams.

Aiming at the effect of principal stress rotation (PSR) in gently inclined coal seam roadways, this study has established a strength criterion that comprehensively considers the coupling effects of multiple factors. Through integrated theoretical analysis, numerical simulation, and physical model testing, this study quantifies the influence of critical parameters on support stability, encompassing principal stress deflection angle, bolt support angle, damage factor, principal stress ratio, and friction coefficient. Quantitative analysis demonstrates that parameter sensitivity exhibits the following hierarchy: damage factor > principal stress deflection angle > principal stress ratio > friction coefficient.

Robust partial nitrification and anammox under low-strength nitrogen condition by regulating organic-induced symbiosis of denitrifiers and anammox bacteria.

Low-strength nitrogen usually limits the efficiency of partial nitrification and anaerobic ammonium oxidation (anammox). To address this challenge, an organic-induced regulation strategy based on microbial interaction characteristics was proposed. Short-range addition of acetate for bio-screening is essential for achieving this regulation.

Constitutive relationship between pore-permeability and molecular structure of bituminous coal based on the Kozeny-Carman equation.

The cell structure of three different densities of bituminous coal molecules was modeled and optimized by using Material Studio (MS) to reveal the mathematical relationship between the porosity and permeability of bituminous coal. The internal surface area was analyzed using the Connolly Surface module, and the specific surface area of the molecules was obtained by mass conversion; the grey processing method was used to evaluate the cell structure porosity, and the pore-permeability constitutive relationship of bituminous coal molecules was established by drawing on the Kozeny-Carman (KC) equation. The results show that the maximum value of 0.

Research on the migration patterns and termination pressure of grouting slurry in horizontal boreholes within deep limestone aquifers.

Because the law of slurry diffusion in horizontal grouting holes in deep limestone aquifers is unclear, and the key grouting parameters in grouting design and engineering practice lack a theoretical basis, the grouting process cannot be effectively controlled, and the grouting effect cannot be guaranteed. Therefore, this study comprehensively adopts laboratory tests, theoretical derivation, numerical analysis, comparative verification, and numerical simulation to study the influence characteristics of the theoretically calculated slurry diffusion form and inclination angle, which are similar to those of the physical model test and numerical simulation results. Under different grouting pressures, fracture inclinations (excluding 0°), fracture openings, and slurry water-cement ratios, the slurry diffusion form was approximately oval and symmetrical along the central vertical line, and the maximum and minimum slurry diffusion distances appeared at azimuths of 180°and 0°, respectively.

Carbon Dioxide Gas Sensor Based on Terahertz Metasurface with Asymmetric Cross-Shaped Holes Empowered by Quasi-Bound States in the Continuum.

In this paper, a novel type of polarization-insensitive terahertz metal metasurface with cross-shaped holes is presented, which is designed based on the theory of bound states in continuous media. The fundamental unit of the metasurface comprises a metal tungsten sheet with a cross-shaped hole structure. A thorough analysis of the optical properties and the quasi-BIC response is conducted using the finite element method.

Research on the type and expansion mechanism of internal cracks in rocks under the action of PDC.

The rock fragmentation mechanism of polycrystalline diamond compact (PDC) constitutes a fundamental research focus in petroleum and mining engineering. This study presents an experimental investigation into crack propagation failure characteristics during cutter-rock interaction. Through an integrated experimental approach combining mechanical testing with digital image correlation (DIC) monitoring, the complete failure process from microcrack initiation to macroscopic fracture network development was quantitatively characterized.