Search Results (3,669)

Optimizing the operating temperature of lithium-ion batteries is critical for safe, reliable, and efficient cell operation. Manufacturers’ recommendations vary in this area, which is primarily determined by the cells’ chemical composition and internal structural characteristics. Most manufacturers define the maximum charging voltage level as the same or close to the same value, but there are significant differences in the lower threshold voltage. Lithium-ion cells exhibit increased internal resistance at lower state-of-charge levels, resulting in elevated heat generation during operation, with intensity proportional to the depth of discharge. However, using a too low voltage threshold causes a significant loss of usable capacity, which reduces the cell’s energy utilization. The present research aims to define and analyze the optimal value of the lower voltage threshold more precisely, considering both thermal development and usable capacity aspects. A further objective is to determine an optimal energy safety margin level that provides a suitable compromise for longer-term storage. Different 18650 and 21700 standard lithium-ion cell types were tested using various load profiles. The results show that the two cell formats have different electro-thermal behaviors. The 21700 cells show a clear increase in thermal efficiency at around 3.1 V. In contrast, the 18650 cells have a heating pattern that depends heavily on the load. This requires selecting a cutoff that adapts to the discharge rate to prevent excessive thermal stress. These findings indicate that a fixed lower threshold voltage for all cells is not ideal. Instead, we need cutoff strategies that are specific to each cell and can change dynamically. The TER-based evaluation introduced in this work provides a practical framework for defining these adaptive limits. It may improve control in battery management systems in real-world applications. Full article

Ischemic heart disease (IHD), the leading causes of cardiovascular morbidity and mortality worldwide, is currently treated though revascularization strategies such as pharmacological thrombolysis, coronary artery bypass grafting (CABG), and percutaneous coronary intervention (PCI). However, the restoration of blood flow often induces cardiac dysfunction, known as myocardial ischemia–reperfusion injury (MIRI). The pathogenesis of MIRI involves a complex, multifactorial process characterized by the interplay of diverse pathophysiological mechanisms, including oxidative stress, intracellular calcium overload, inflammatory cascade activation, apoptosis, autophagy, and microvascular endothelial dysfunction. In recent years, modified RNA (modRNA) technology has emerged as a novel therapeutic strategy for MIRI due to its enhanced molecular stability, reduced immunogenicity, and controllable transient protein expression. Studies have demonstrated that optimized modRNA delivery systems enable efficient, localized expression of therapeutic genes (e.g., antioxidant, anti-apoptotic, and pro-angiogenic factors) at injury sites, significantly mitigating MIRI-associated pathological damage. Nevertheless, significant challenges remain in clinical translation, such as delivery system targeting, transfection efficiency and cytotoxicity. This review focuses on recent advances in the development and application of modRNA-based delivery systems for MIRI treatment. Understanding the molecular mechanisms of MIRI and the structural characteristics and application of modRNA may encourage researchers to explore promising therapeutic modalities for addressing reperfusion-related cardiac injury. Full article

To address the issue of low efficiency in recovering low-frequency vibration energy during vehicle operation, this paper proposes a piezoelectric energy capture harvester based on wheel vibration. The device employs a parallel configuration of dual cantilever beam piezoelectric transducers in its mechanical structure, with additional mass blocks to optimize its resonant characteristics in the low-frequency range. A synchronous switch energy harvesting circuit was designed. By actively synchronizing the switch with the peak output voltage of the piezoelectric element, it effectively circumvents the turn-on voltage threshold limitations of diodes in bridge rectifier circuits, thereby enhancing energy conversion efficiency. A dynamic model of this device was established, and multiphysics simulation analysis was conducted using COMSOL-Multiphysics to investigate the modal characteristics, stress distribution, and output performance of the energy harvester. This revealed the influence of the piezoelectric vibrator’s thickness ratio and the mass block’s weight on its power generation capabilities. Experimental results indicate that under 20 Hz, 12 V sinusoidal excitation, the system achieves an average output power of 3.019 mW with an average open-circuit voltage reaching 16.70 V. Under simulated road test conditions at 70 km/h, the output voltage remained stable at 6.86 V, validating its feasibility in real-world applications. This study presents an efficient and reliable solution for self-powering in-vehicle wireless sensors and low-power electronic devices through mechatronic co-design. Full article

The development of China’s manganese (Mn) industries has caused severe water and soil pollution, threatening ecological and human health. Microbes are usually regarded as an important indicator of environmental pollution assessment. However, the current understanding of microbial community characteristics and their formation mechanisms in Mn production areas remains limited. In order to address this, soil properties and microbial structural characteristics across different functional zones in a typical Mn electrolysis plant in China’s “Manganese Triangle” were investigated via metagenomic sequencing. Results showed soil Mn levels significantly exceeded background values, indicating high environmental risk. Acidobacteria and Proteobacteria were dominant phyla. Microbial abundance was lowest in the adjacent natural reservoir, whereas diversity was highest in the sewage treatment plant. Correlation analyses identified Mn, nitrate nitrogen, ammonium nitrogen, pH, and moisture as key environmental drivers, with Mn being the primary one. Metagenomic analysis revealed abundant Mn resistance genes, enabling microbial survival under high Mn stress. This study demonstrated that excessive Mn exposure enriched Mn-resistant genes, thereby shaping unique microbial communities dominated by Mn-resistant bacteria. These findings clarified the structural characteristics and adaptive mechanisms of soil microbial communities in Mn-contaminated areas, providing a theoretical basis for ecological risk management and bioremediation. Full article

The enrichment laws and key controlling factors of coalbed methane (CBM) in the Xishanyao Formation of the Hedong mining area remain unclear, restricting exploration progress. Based on well data and experimental analyses, this study investigates CBM enrichment characteristics and geological controls using genetic identification diagrams. Results demonstrate that CBM exhibits a “high in northwest and low in southeast” planar distribution. Vertically, CBM content is extremely low above 360 m due to weathering oxidation and burnt zone effects, increases within the 360–950 m interval (peaking at 750–950 m), and declines from 950 to 1200 m because of limited gas contribution. Genetic analysis indicates predominantly primary biogenic gas, with a minor component of early thermogenic gas. Enrichment is controlled by structure and hydrogeology: the medium-depth range (358–936 m) on the northern syncline limb and western part of the northern monoclinal zone forms a high-efficiency enrichment zone due to compressive stress from reverse faults and high mineralization groundwater (TDS > 8000 mg/L). While the southern limb, characterized by high-angle tensile fractures and active groundwater runoff, suffers gas loss and generally low gas content (<3.5 m³/t). This study clarifies CBM enrichment laws and enrichment mechanisms, supporting exploration of low-rank CBM in the Hedong mining area. Full article

During preliminary reconnaissance at a hydropower station site in Southwestern China, a unique phenomenon of deep-seated fractures was identified within the slopes, which were symmetrically developed on both banks. These features occur within unloading zones and manifest as tensile fractures with deep-seated fractures exhibiting unloading characteristics. This study systematically analyzes the spatial distribution, developed patterns, and structural attributes of these deep fractures. Through numerical model of stress field dynamics during valley evolution, we investigate the relationship between stress states and deep fracture formation. Research demonstrates that these fractures result from energy release through unloading at stress-concentration zones in slope interiors, driven by rapid valley incision under high in situ stress conditions. This process is further conditioned by specific slope geometries, rock mass structures, and geomorphic settings. Crucially, river incision rate governs fracture depth, while the number of incision cycles significantly controls fracture aperture. These findings provide a theory for understanding deep-seated slope failure mechanisms and engineering mitigation in analogous geological environments. Full article

Rock slope toppling failure is a typical type of slope disaster. It is crucial for engineering practice to quickly and accurately evaluate the toppling stability of rock slopes under seismic loads. Based on Liu’s pseudo-continuous medium method, the geomechanical model for evaluating the stability of rock slope block toppling subjected to seismic loads, considering non-orthogonal characteristics of the structural planes, is established, and the analytical solution for toppling failure is proposed. The relationship between the normal and shear stresses acting at the block base is discussed, and the formula for determining the location of the failure mode transition point in different cases is deduced. Through programmed analysis, the impact of the seismic load on slope stability and the influence of key parameters on the critical seismic influence coefficient are systematically investigated. The research results indicate that the seismic load has a significant impact on slope stability. With increases in the seismic influence coefficient, or decreases in the angle between the seismic load and the horizontal plane, the supporting force required for slope stability increases, and the transition point from toppling to sliding moves towards the slope toe. It is also shown that, when the seismic influence coefficient reaches the critical value, the slope will slide as a whole without toppling. The value of the critical seismic influence coefficient is positively correlated with the internal friction angle of the block base, and negatively correlated with the direction of the seismic load, the internal friction angle of the block side and the dip angle of the block base. This study provides theoretical support for evaluating the block toppling stability of slopes in seismic-prone areas. Full article

Recent developments in machine learning have enabled prediction models that estimate not only hydrodynamic force coefficients but also full CFD fields. Unlike conventional surrogate models that focus primarily on integrated quantities, such approaches can provide real-time predictions of pressure and wall shear stress distributions, making them highly promising for applications in ship hydrodynamic design where detailed surface flow characteristics are essential. In this study, we address the low prediction accuracy observed near protruding appendages in U-Net-based field prediction models by introducing a positional encoding (PE)-enhanced data processing scheme and evaluating its performance across a dataset of 500 SUBOFF variants. While PE enhances prediction accuracy, especially for the sail, its effectiveness is constrained by the boundary discontinuity introduced at the 12 o’clock seam. To resolve this structural limitation and ensure consistent accuracy across components, the projection seam is relocated to the 6 o’clock position, where high-gradient flow features are less concentrated. This modification produces clear quantitative gains: the drag-integrated MAPE decreases from 3.61% to 1.85%, and the mean field-level errors of $∆{\mathrm{C}}_{\mathrm{p}}$ and $∆{\mathrm{C}}_{\mathrm{f}}$ are reduced by approximately 5.6% across the dataset. These results demonstrate that combining PE with seam relocation substantially enhances the model’s ability to reconstruct fine-scale flow features, improving the overall robustness and physical reliability of U-Net-based surface field prediction for submarine hull forms. Full article

Adhesively bonded joints are extensively utilized in structural assemblies involving metals, composites, and hybrid materials due to their favorable mechanical and manufacturing characteristics. However, their performance under high-velocity impacts—common in aerospace, automotive, and defense applications—remains insufficiently understood. This work investigates the high-velocity performance and subsequent tensile response of adhesively bonded single-lap joints (SLJs) by integrating experimental testing with numerical simulations. High-velocity impacts were applied to SLJs fabricated from 4 mm aluminum adherends with overlap lengths of 15 mm and 25 mm, using a 1.25 g projectile at 288 m/s, followed by quasi-static tensile assessment. Experimental findings revealed substantial degradation in tensile strength for the 15 mm overlap configuration (reduced the load-bearing capacity by about 33% (from ~12 kN to ~8 kN)), while the 25 mm overlap retained its structural integrity. Finite element simulations conducted in ABAQUS 2021 employed the Johnson–Cook constitutive model for the adherends and a cohesive zone model for the adhesive layer, successfully replicating damage evolution and stress distributions. The results highlight the critical role of geometric parameters—particularly overlap length and adherend thickness—in determining the damage tolerance and residual load-bearing capacity of SLJs subjected to high-velocity impacts. These insights contribute to the development of more robust bonded joint designs for impact-prone environments. Full article

Sulfonate greases, which have excellent performance characteristics—high dropping point, good mechanical and structural stability, water resistance, high thermal oxidation stability, and good anticorrosive properties—are widely used in various industries. The greases are exposed to water during operation: moisture in the environment, water-based coolants, operation in the presence of water vapor, etc. Water can affect the properties of the greases during operation. The subject of the study was a commercial complex grease thickened with overbased calcium sulfonate, with a water additive in amounts ranging from 1% to 50% by weight. This paper presents two standardized methods for testing the thermal oxidation stability of lubricants—according to ASTM D942 and ASTM D8206, in standard programs, and with an extension of oxidation duration to 100 h and a temperature increase to 100 °C. The aim of the study was to investigate how the addition of water affected the thermal oxidation stability of this grease. The presentation concludes with an analysis of FTIR differential spectra. The tests showed that as the water content in the grease samples increased, its resistance to oxidation decreased. Water also caused a change in the consistency of the grease at a concentration of just 1% by weight. Mechanical stress affected the thermal oxidation stability of the grease tested. Each method presented separate mechanisms of oxidation initiation, including different sample quantities during the test, the presence of water in the classic method, and different contact with oxygen as a catalyst for this reaction. The work provided a comprehensive presentation of the possibilities for testing the thermal oxidation resistance of greases and a detailed comparison of the two methods. Full article

The increasing global demand for cleaner transportation has intensified the importance of efficient AdBlue^® (AUS32) production, a key chemical in selective catalytic reduction (SCR) systems that reduces nitrogen oxides (NOx) emissions from diesel engines. This work presents a computational fluid dynamics (CFD) simulation study of the urea–water mixing process within a high shear mixer (HSM), aiming to enhance the sustainability of AdBlue^® manufacturing. The model evaluates the hydrodynamic characteristics critical to optimising the dissolution of urea pellets in deionised water, which conventionally requires significant preheating. Experimental validation was conducted by comparing pressure drop simulation results with operational data from an active industrial facility in the United Kingdom. Therefore, this study validates the CFD model against an industrial two-stage Rotor–stator under real operating conditions. The computational framework combines a refined mesh with the k-ω SST turbulent model to resolve flow structures and capture near-wall effects and shear stress transport in complex flow domains. The results reveal opportunities for process optimisation, particularly in reducing thermal energy input without compromising solubility, thus offering a more sustainable pathway for AdBlue^® production. The main contribution of this work is to close existing gaps in industrial practice and propose and computationally validate strategies to improve the numerical design of HSM for solid dissolution. Full article

Electric vehicle (EV) battery pack cases (BPCs) must withstand mechanical loads such as impact, compression, and vibration to ensure structural integrity and passenger safety. This study evaluates the mechanical durability of a full-scale aluminum BPC using combined experimental testing and finite element analysis (FEA). A bottom impact test, 200 kN compression test, and power spectral density (PSD)-based random vibration test were conducted to simulate representative operating and handling conditions. The numerical model replicated boundary conditions and load profiles identical to the experiments, enabling a direct comparison of stress distribution and deformation characteristics. The results demonstrated that stress and displacement trends predicted by FEA closely matched experimental observations, with stress concentrations appearing at corner and frame junction regions and less than 1 mm deformation recorded under peak compression loading. Vibration responses were most pronounced in the vertical direction, without bolt loosening or structural damage. These results verify the reliability of the proposed BPC design and provide quantitative evidence supporting simulation-driven lightweight battery enclosure development. Full article

The shale oil reservoirs of Member 7 of the Triassic Yanchang Formation in the Longdong Area of the Ordos Basin have attracted widespread attention due to their unique geological characteristics and enormous development potential. As the core factor controlling reservoir storage capacity and hydrocarbon flow efficiency, the precise characterization and quantitative analysis of pore structure are the prerequisite and key for reservoir evaluation and development plan optimization. All samples selected in this study were collected from the shale of Member 7 of the Triassic Yanchang Formation and were classified into two categories: medium-organic-rich shales (total organic carbon, TOC: 2–6%; TOC refers to the total organic carbon content in rocks, indicating organic matter abundance; unit: %) and high-organic-rich shales (TOC: >6%). The mineral composition and organic geochemical parameters of the shale were determined via X-ray diffraction (XRD) and Rock-Eval pyrolysis experiments, respectively. Meanwhile, pore structure characteristics were analyzed by combining low-temperature nitrogen adsorption–desorption experiments before and after extraction, and multifractal analysis was used to systematically investigate the differences in pore heterogeneity of shale and their influencing factors. The results show that the specific surface area (SSA) and total pore volume (TPV) of shale increased after extraction, while the change in average pore diameter (APD) varied. Multifractal analysis indicates that the micropores of shale both before and after extraction exhibit significant multifractal characteristics; after extraction, pore connectivity is improved, but the changes in pore heterogeneity are inconsistent. The pore connectivity of shale first increases and then decreases with the increase in TOC content and pyrolysis parameter S₂ content. The better the pore connectivity of shale, the lower the content of light-component saturated hydrocarbons and the relatively higher the content of heavy-component resins in the extractable organic matter (EOM). Brittle minerals can provide a rigid framework to inhibit compaction and are prone to forming natural microfractures under tectonic stress, thereby promoting pore connectivity. In contrast, clay minerals, due to their plasticity, are prone to deformation and filling pore throats during compaction, thus reducing pore connectivity. This study provides a theoretical basis for the evaluation and development of shale reservoirs in the Longdong Area. Full article

Valine-glutamine motif proteins (VQ), plant-specific transcriptional co-regulators harboring the conserved FxxhVQxhTG motif, play pivotal roles in coordinating plant stress adaptation through dynamic interactions with WRKY transcription factors (WRKY), mitogen-activated protein kinases (MAPKs) cascades, and hormone signaling pathways. Evolutionary analyses reveal the characteristics of their evolutionary protection and ancient origin, with lineage-specific expansion via genome duplication events. Structurally, compact genes lacking introns and the presence of intrinsic disordered regions (IDRs) facilitate rapid stress responses and versatile protein interactions. Functionally, VQ proteins orchestrate abiotic stress tolerance (e.g., drought, salinity, temperature extremes) by modulating reactive oxygen species (ROS) homeostasis, osmotic balance, and abscisic acid/salicylic acid (ABA/SA)-mediated signaling. Concurrently, they enhance biotic stress resistance via pathogen-responsive WRKY-VQ modules that regulate defense gene expression and hormone crosstalk. Despite advances, challenges persist in deciphering post-translational modifications, tissue-specific functions, and cross-stress integration mechanisms. Harnessing CRISPR-based editing and multi-omics approaches will accelerate the exploitation of VQ genes for developing climate-resilient crops. This review synthesizes the molecular architecture, evolutionary dynamics, and multifunctional regulatory networks of VQ proteins, providing a roadmap for their utilization in sustainable agriculture. Full article

Coronary artery bypass grafting (CABG) remains a cornerstone of treatment for patients with advanced or complex coronary artery disease, yet long-term success is influenced by graft patency, progression of native disease, and ventricular remodeling. Optimizing the follow-up of these patients requires a structured approach in which multimodality cardiovascular imaging plays a central role. Echocardiography remains the first-line modality, providing readily available assessment of ventricular function, valvular competence, and wall motion, while advanced techniques, such as strain imaging and myocardial work, enhance sensitivity for subclinical dysfunction. Coronary computed tomography angiography (CCTA) offers excellent diagnostic accuracy for graft patency and native coronary anatomy, with emerging applications of CT perfusion and fractional flow reserve derived from CT (FFR-CT) expanding its ability to assess lesion-specific ischemia. Cardiovascular magnetic resonance (CMR) provides comprehensive tissue characterization, quantifying scar burden, viability, and inducible ischemia, and stress CMR protocols have demonstrated both safety and independent prognostic value in post-CABG cohorts. Nuclear imaging with single-photon emission computed tomography (SPECT) and positron emission tomography (PET) remains essential for quantifying perfusion, viability, and absolute myocardial blood flow, with hybrid PET/CT approaches offering further refinement in patients with recurrent symptoms. In patients after CABG, multimodality imaging is tailored to the patient’s characteristics, symptoms, and pre-test probability of disease progression. In asymptomatic patients, imaging focuses on surveillance, risk stratification, and the early detection of subclinical abnormalities, whereas in symptomatic individuals, it focuses on establishing the diagnosis, defining prognosis, and guiding therapeutic interventions. Therefore, the aim of our review is to propose updated and comprehensive guidance on the crucial role of multimodality cardiovascular imaging in the evaluation and management of post-CABG patients and to provide a practical, evidence-based framework for optimizing outcomes. Full article